1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra. 5 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>. 6 * Copyright 2009-2013 Konstantin Belousov <kib@FreeBSD.ORG>. 7 * Copyright 2012 John Marino <draco@marino.st>. 8 * Copyright 2014-2017 The FreeBSD Foundation 9 * All rights reserved. 10 * 11 * Portions of this software were developed by Konstantin Belousov 12 * under sponsorship from the FreeBSD Foundation. 13 * 14 * Redistribution and use in source and binary forms, with or without 15 * modification, are permitted provided that the following conditions 16 * are met: 17 * 1. Redistributions of source code must retain the above copyright 18 * notice, this list of conditions and the following disclaimer. 19 * 2. Redistributions in binary form must reproduce the above copyright 20 * notice, this list of conditions and the following disclaimer in the 21 * documentation and/or other materials provided with the distribution. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 25 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 26 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 27 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 28 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 29 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 30 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 31 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 32 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 33 */ 34 35 /* 36 * Dynamic linker for ELF. 37 * 38 * John Polstra <jdp@polstra.com>. 39 */ 40 41 #include <sys/cdefs.h> 42 __FBSDID("$FreeBSD$"); 43 44 #include <sys/param.h> 45 #include <sys/mount.h> 46 #include <sys/mman.h> 47 #include <sys/stat.h> 48 #include <sys/sysctl.h> 49 #include <sys/uio.h> 50 #include <sys/utsname.h> 51 #include <sys/ktrace.h> 52 53 #include <dlfcn.h> 54 #include <err.h> 55 #include <errno.h> 56 #include <fcntl.h> 57 #include <stdarg.h> 58 #include <stdio.h> 59 #include <stdlib.h> 60 #include <string.h> 61 #include <unistd.h> 62 63 #include "debug.h" 64 #include "rtld.h" 65 #include "libmap.h" 66 #include "paths.h" 67 #include "rtld_tls.h" 68 #include "rtld_printf.h" 69 #include "rtld_malloc.h" 70 #include "rtld_utrace.h" 71 #include "notes.h" 72 #include "rtld_libc.h" 73 74 /* Types. */ 75 typedef void (*func_ptr_type)(void); 76 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 77 78 79 /* Variables that cannot be static: */ 80 extern struct r_debug r_debug; /* For GDB */ 81 extern int _thread_autoinit_dummy_decl; 82 extern void (*__cleanup)(void); 83 84 85 /* 86 * Function declarations. 87 */ 88 static const char *basename(const char *); 89 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 90 const Elf_Dyn **, const Elf_Dyn **); 91 static bool digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *, 92 const Elf_Dyn *); 93 static bool digest_dynamic(Obj_Entry *, int); 94 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 95 static void distribute_static_tls(Objlist *, RtldLockState *); 96 static Obj_Entry *dlcheck(void *); 97 static int dlclose_locked(void *, RtldLockState *); 98 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, 99 int lo_flags, int mode, RtldLockState *lockstate); 100 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 101 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 102 static bool donelist_check(DoneList *, const Obj_Entry *); 103 static void errmsg_restore(char *); 104 static char *errmsg_save(void); 105 static void *fill_search_info(const char *, size_t, void *); 106 static char *find_library(const char *, const Obj_Entry *, int *); 107 static const char *gethints(bool); 108 static void hold_object(Obj_Entry *); 109 static void unhold_object(Obj_Entry *); 110 static void init_dag(Obj_Entry *); 111 static void init_marker(Obj_Entry *); 112 static void init_pagesizes(Elf_Auxinfo **aux_info); 113 static void init_rtld(caddr_t, Elf_Auxinfo **); 114 static void initlist_add_neededs(Needed_Entry *, Objlist *); 115 static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *); 116 static int initlist_objects_ifunc(Objlist *, bool, int, RtldLockState *); 117 static void linkmap_add(Obj_Entry *); 118 static void linkmap_delete(Obj_Entry *); 119 static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 120 static void unload_filtees(Obj_Entry *, RtldLockState *); 121 static int load_needed_objects(Obj_Entry *, int); 122 static int load_preload_objects(void); 123 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 124 static void map_stacks_exec(RtldLockState *); 125 static int obj_disable_relro(Obj_Entry *); 126 static int obj_enforce_relro(Obj_Entry *); 127 static Obj_Entry *obj_from_addr(const void *); 128 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 129 static void objlist_call_init(Objlist *, RtldLockState *); 130 static void objlist_clear(Objlist *); 131 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 132 static void objlist_init(Objlist *); 133 static void objlist_push_head(Objlist *, Obj_Entry *); 134 static void objlist_push_tail(Objlist *, Obj_Entry *); 135 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 136 static void objlist_remove(Objlist *, Obj_Entry *); 137 static int open_binary_fd(const char *argv0, bool search_in_path, 138 const char **binpath_res); 139 static int parse_args(char* argv[], int argc, bool *use_pathp, int *fdp, 140 const char **argv0); 141 static int parse_integer(const char *); 142 static void *path_enumerate(const char *, path_enum_proc, const char *, void *); 143 static void print_usage(const char *argv0); 144 static void release_object(Obj_Entry *); 145 static int relocate_object_dag(Obj_Entry *root, bool bind_now, 146 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 147 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 148 int flags, RtldLockState *lockstate); 149 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 150 RtldLockState *); 151 static int resolve_object_ifunc(Obj_Entry *, bool, int, RtldLockState *); 152 static int rtld_dirname(const char *, char *); 153 static int rtld_dirname_abs(const char *, char *); 154 static void *rtld_dlopen(const char *name, int fd, int mode); 155 static void rtld_exit(void); 156 static void rtld_nop_exit(void); 157 static char *search_library_path(const char *, const char *, const char *, 158 int *); 159 static char *search_library_pathfds(const char *, const char *, int *); 160 static const void **get_program_var_addr(const char *, RtldLockState *); 161 static void set_program_var(const char *, const void *); 162 static int symlook_default(SymLook *, const Obj_Entry *refobj); 163 static int symlook_global(SymLook *, DoneList *); 164 static void symlook_init_from_req(SymLook *, const SymLook *); 165 static int symlook_list(SymLook *, const Objlist *, DoneList *); 166 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 167 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 168 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 169 static void trace_loaded_objects(Obj_Entry *); 170 static void unlink_object(Obj_Entry *); 171 static void unload_object(Obj_Entry *, RtldLockState *lockstate); 172 static void unref_dag(Obj_Entry *); 173 static void ref_dag(Obj_Entry *); 174 static char *origin_subst_one(Obj_Entry *, char *, const char *, 175 const char *, bool); 176 static char *origin_subst(Obj_Entry *, const char *); 177 static bool obj_resolve_origin(Obj_Entry *obj); 178 static void preinit_main(void); 179 static int rtld_verify_versions(const Objlist *); 180 static int rtld_verify_object_versions(Obj_Entry *); 181 static void object_add_name(Obj_Entry *, const char *); 182 static int object_match_name(const Obj_Entry *, const char *); 183 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 184 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 185 struct dl_phdr_info *phdr_info); 186 static uint32_t gnu_hash(const char *); 187 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 188 const unsigned long); 189 190 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported; 191 void _r_debug_postinit(struct link_map *) __noinline __exported; 192 193 int __sys_openat(int, const char *, int, ...); 194 195 /* 196 * Data declarations. 197 */ 198 static char *error_message; /* Message for dlerror(), or NULL */ 199 struct r_debug r_debug __exported; /* for GDB; */ 200 static bool libmap_disable; /* Disable libmap */ 201 static bool ld_loadfltr; /* Immediate filters processing */ 202 static char *libmap_override; /* Maps to use in addition to libmap.conf */ 203 static bool trust; /* False for setuid and setgid programs */ 204 static bool dangerous_ld_env; /* True if environment variables have been 205 used to affect the libraries loaded */ 206 bool ld_bind_not; /* Disable PLT update */ 207 static char *ld_bind_now; /* Environment variable for immediate binding */ 208 static char *ld_debug; /* Environment variable for debugging */ 209 static char *ld_library_path; /* Environment variable for search path */ 210 static char *ld_library_dirs; /* Environment variable for library descriptors */ 211 static char *ld_preload; /* Environment variable for libraries to 212 load first */ 213 static const char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 214 static const char *ld_tracing; /* Called from ldd to print libs */ 215 static char *ld_utrace; /* Use utrace() to log events. */ 216 static struct obj_entry_q obj_list; /* Queue of all loaded objects */ 217 static Obj_Entry *obj_main; /* The main program shared object */ 218 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 219 static unsigned int obj_count; /* Number of objects in obj_list */ 220 static unsigned int obj_loads; /* Number of loads of objects (gen count) */ 221 222 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 223 STAILQ_HEAD_INITIALIZER(list_global); 224 static Objlist list_main = /* Objects loaded at program startup */ 225 STAILQ_HEAD_INITIALIZER(list_main); 226 static Objlist list_fini = /* Objects needing fini() calls */ 227 STAILQ_HEAD_INITIALIZER(list_fini); 228 229 Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 230 231 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 232 233 extern Elf_Dyn _DYNAMIC; 234 #pragma weak _DYNAMIC 235 236 int dlclose(void *) __exported; 237 char *dlerror(void) __exported; 238 void *dlopen(const char *, int) __exported; 239 void *fdlopen(int, int) __exported; 240 void *dlsym(void *, const char *) __exported; 241 dlfunc_t dlfunc(void *, const char *) __exported; 242 void *dlvsym(void *, const char *, const char *) __exported; 243 int dladdr(const void *, Dl_info *) __exported; 244 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *), 245 void (*)(void *), void (*)(void *), void (*)(void *)) __exported; 246 int dlinfo(void *, int , void *) __exported; 247 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported; 248 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported; 249 int _rtld_get_stack_prot(void) __exported; 250 int _rtld_is_dlopened(void *) __exported; 251 void _rtld_error(const char *, ...) __exported; 252 253 /* Only here to fix -Wmissing-prototypes warnings */ 254 int __getosreldate(void); 255 func_ptr_type _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp); 256 Elf_Addr _rtld_bind(Obj_Entry *obj, Elf_Size reloff); 257 258 259 int npagesizes; 260 static int osreldate; 261 size_t *pagesizes; 262 263 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 264 static int max_stack_flags; 265 266 /* 267 * Global declarations normally provided by crt1. The dynamic linker is 268 * not built with crt1, so we have to provide them ourselves. 269 */ 270 char *__progname; 271 char **environ; 272 273 /* 274 * Used to pass argc, argv to init functions. 275 */ 276 int main_argc; 277 char **main_argv; 278 279 /* 280 * Globals to control TLS allocation. 281 */ 282 size_t tls_last_offset; /* Static TLS offset of last module */ 283 size_t tls_last_size; /* Static TLS size of last module */ 284 size_t tls_static_space; /* Static TLS space allocated */ 285 static size_t tls_static_max_align; 286 Elf_Addr tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 287 int tls_max_index = 1; /* Largest module index allocated */ 288 289 static bool ld_library_path_rpath = false; 290 bool ld_fast_sigblock = false; 291 292 /* 293 * Globals for path names, and such 294 */ 295 const char *ld_elf_hints_default = _PATH_ELF_HINTS; 296 const char *ld_path_libmap_conf = _PATH_LIBMAP_CONF; 297 const char *ld_path_rtld = _PATH_RTLD; 298 const char *ld_standard_library_path = STANDARD_LIBRARY_PATH; 299 const char *ld_env_prefix = LD_; 300 301 static void (*rtld_exit_ptr)(void); 302 303 /* 304 * Fill in a DoneList with an allocation large enough to hold all of 305 * the currently-loaded objects. Keep this as a macro since it calls 306 * alloca and we want that to occur within the scope of the caller. 307 */ 308 #define donelist_init(dlp) \ 309 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 310 assert((dlp)->objs != NULL), \ 311 (dlp)->num_alloc = obj_count, \ 312 (dlp)->num_used = 0) 313 314 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 315 if (ld_utrace != NULL) \ 316 ld_utrace_log(e, h, mb, ms, r, n); \ 317 } while (0) 318 319 static void 320 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 321 int refcnt, const char *name) 322 { 323 struct utrace_rtld ut; 324 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG; 325 326 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig)); 327 ut.event = event; 328 ut.handle = handle; 329 ut.mapbase = mapbase; 330 ut.mapsize = mapsize; 331 ut.refcnt = refcnt; 332 bzero(ut.name, sizeof(ut.name)); 333 if (name) 334 strlcpy(ut.name, name, sizeof(ut.name)); 335 utrace(&ut, sizeof(ut)); 336 } 337 338 #ifdef RTLD_VARIANT_ENV_NAMES 339 /* 340 * construct the env variable based on the type of binary that's 341 * running. 342 */ 343 static inline const char * 344 _LD(const char *var) 345 { 346 static char buffer[128]; 347 348 strlcpy(buffer, ld_env_prefix, sizeof(buffer)); 349 strlcat(buffer, var, sizeof(buffer)); 350 return (buffer); 351 } 352 #else 353 #define _LD(x) LD_ x 354 #endif 355 356 /* 357 * Main entry point for dynamic linking. The first argument is the 358 * stack pointer. The stack is expected to be laid out as described 359 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 360 * Specifically, the stack pointer points to a word containing 361 * ARGC. Following that in the stack is a null-terminated sequence 362 * of pointers to argument strings. Then comes a null-terminated 363 * sequence of pointers to environment strings. Finally, there is a 364 * sequence of "auxiliary vector" entries. 365 * 366 * The second argument points to a place to store the dynamic linker's 367 * exit procedure pointer and the third to a place to store the main 368 * program's object. 369 * 370 * The return value is the main program's entry point. 371 */ 372 func_ptr_type 373 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 374 { 375 Elf_Auxinfo *aux, *auxp, *auxpf, *aux_info[AT_COUNT]; 376 Objlist_Entry *entry; 377 Obj_Entry *last_interposer, *obj, *preload_tail; 378 const Elf_Phdr *phdr; 379 Objlist initlist; 380 RtldLockState lockstate; 381 struct stat st; 382 Elf_Addr *argcp; 383 char **argv, **env, **envp, *kexecpath, *library_path_rpath; 384 const char *argv0, *binpath; 385 caddr_t imgentry; 386 char buf[MAXPATHLEN]; 387 int argc, fd, i, mib[4], old_osrel, osrel, phnum, rtld_argc; 388 size_t sz; 389 #ifdef __powerpc__ 390 int old_auxv_format = 1; 391 #endif 392 bool dir_enable, direct_exec, explicit_fd, search_in_path; 393 394 /* 395 * On entry, the dynamic linker itself has not been relocated yet. 396 * Be very careful not to reference any global data until after 397 * init_rtld has returned. It is OK to reference file-scope statics 398 * and string constants, and to call static and global functions. 399 */ 400 401 /* Find the auxiliary vector on the stack. */ 402 argcp = sp; 403 argc = *sp++; 404 argv = (char **) sp; 405 sp += argc + 1; /* Skip over arguments and NULL terminator */ 406 env = (char **) sp; 407 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 408 ; 409 aux = (Elf_Auxinfo *) sp; 410 411 /* Digest the auxiliary vector. */ 412 for (i = 0; i < AT_COUNT; i++) 413 aux_info[i] = NULL; 414 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 415 if (auxp->a_type < AT_COUNT) 416 aux_info[auxp->a_type] = auxp; 417 #ifdef __powerpc__ 418 if (auxp->a_type == 23) /* AT_STACKPROT */ 419 old_auxv_format = 0; 420 #endif 421 } 422 423 #ifdef __powerpc__ 424 if (old_auxv_format) { 425 /* Remap from old-style auxv numbers. */ 426 aux_info[23] = aux_info[21]; /* AT_STACKPROT */ 427 aux_info[21] = aux_info[19]; /* AT_PAGESIZESLEN */ 428 aux_info[19] = aux_info[17]; /* AT_NCPUS */ 429 aux_info[17] = aux_info[15]; /* AT_CANARYLEN */ 430 aux_info[15] = aux_info[13]; /* AT_EXECPATH */ 431 aux_info[13] = NULL; /* AT_GID */ 432 433 aux_info[20] = aux_info[18]; /* AT_PAGESIZES */ 434 aux_info[18] = aux_info[16]; /* AT_OSRELDATE */ 435 aux_info[16] = aux_info[14]; /* AT_CANARY */ 436 aux_info[14] = NULL; /* AT_EGID */ 437 } 438 #endif 439 440 /* Initialize and relocate ourselves. */ 441 assert(aux_info[AT_BASE] != NULL); 442 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 443 444 __progname = obj_rtld.path; 445 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 446 environ = env; 447 main_argc = argc; 448 main_argv = argv; 449 450 if (aux_info[AT_BSDFLAGS] != NULL && 451 (aux_info[AT_BSDFLAGS]->a_un.a_val & ELF_BSDF_SIGFASTBLK) != 0) 452 ld_fast_sigblock = true; 453 454 trust = !issetugid(); 455 direct_exec = false; 456 457 md_abi_variant_hook(aux_info); 458 459 fd = -1; 460 if (aux_info[AT_EXECFD] != NULL) { 461 fd = aux_info[AT_EXECFD]->a_un.a_val; 462 } else { 463 assert(aux_info[AT_PHDR] != NULL); 464 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr; 465 if (phdr == obj_rtld.phdr) { 466 if (!trust) { 467 _rtld_error("Tainted process refusing to run binary %s", 468 argv0); 469 rtld_die(); 470 } 471 direct_exec = true; 472 473 dbg("opening main program in direct exec mode"); 474 if (argc >= 2) { 475 rtld_argc = parse_args(argv, argc, &search_in_path, &fd, &argv0); 476 explicit_fd = (fd != -1); 477 binpath = NULL; 478 if (!explicit_fd) 479 fd = open_binary_fd(argv0, search_in_path, &binpath); 480 if (fstat(fd, &st) == -1) { 481 _rtld_error("Failed to fstat FD %d (%s): %s", fd, 482 explicit_fd ? "user-provided descriptor" : argv0, 483 rtld_strerror(errno)); 484 rtld_die(); 485 } 486 487 /* 488 * Rough emulation of the permission checks done by 489 * execve(2), only Unix DACs are checked, ACLs are 490 * ignored. Preserve the semantic of disabling owner 491 * to execute if owner x bit is cleared, even if 492 * others x bit is enabled. 493 * mmap(2) does not allow to mmap with PROT_EXEC if 494 * binary' file comes from noexec mount. We cannot 495 * set a text reference on the binary. 496 */ 497 dir_enable = false; 498 if (st.st_uid == geteuid()) { 499 if ((st.st_mode & S_IXUSR) != 0) 500 dir_enable = true; 501 } else if (st.st_gid == getegid()) { 502 if ((st.st_mode & S_IXGRP) != 0) 503 dir_enable = true; 504 } else if ((st.st_mode & S_IXOTH) != 0) { 505 dir_enable = true; 506 } 507 if (!dir_enable) { 508 _rtld_error("No execute permission for binary %s", 509 argv0); 510 rtld_die(); 511 } 512 513 /* 514 * For direct exec mode, argv[0] is the interpreter 515 * name, we must remove it and shift arguments left 516 * before invoking binary main. Since stack layout 517 * places environment pointers and aux vectors right 518 * after the terminating NULL, we must shift 519 * environment and aux as well. 520 */ 521 main_argc = argc - rtld_argc; 522 for (i = 0; i <= main_argc; i++) 523 argv[i] = argv[i + rtld_argc]; 524 *argcp -= rtld_argc; 525 environ = env = envp = argv + main_argc + 1; 526 dbg("move env from %p to %p", envp + rtld_argc, envp); 527 do { 528 *envp = *(envp + rtld_argc); 529 } while (*envp++ != NULL); 530 aux = auxp = (Elf_Auxinfo *)envp; 531 auxpf = (Elf_Auxinfo *)(envp + rtld_argc); 532 dbg("move aux from %p to %p", auxpf, aux); 533 /* XXXKIB insert place for AT_EXECPATH if not present */ 534 for (;; auxp++, auxpf++) { 535 *auxp = *auxpf; 536 if (auxp->a_type == AT_NULL) 537 break; 538 } 539 /* Since the auxiliary vector has moved, redigest it. */ 540 for (i = 0; i < AT_COUNT; i++) 541 aux_info[i] = NULL; 542 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 543 if (auxp->a_type < AT_COUNT) 544 aux_info[auxp->a_type] = auxp; 545 } 546 547 /* Point AT_EXECPATH auxv and aux_info to the binary path. */ 548 if (binpath == NULL) { 549 aux_info[AT_EXECPATH] = NULL; 550 } else { 551 if (aux_info[AT_EXECPATH] == NULL) { 552 aux_info[AT_EXECPATH] = xmalloc(sizeof(Elf_Auxinfo)); 553 aux_info[AT_EXECPATH]->a_type = AT_EXECPATH; 554 } 555 aux_info[AT_EXECPATH]->a_un.a_ptr = __DECONST(void *, 556 binpath); 557 } 558 } else { 559 _rtld_error("No binary"); 560 rtld_die(); 561 } 562 } 563 } 564 565 ld_bind_now = getenv(_LD("BIND_NOW")); 566 567 /* 568 * If the process is tainted, then we un-set the dangerous environment 569 * variables. The process will be marked as tainted until setuid(2) 570 * is called. If any child process calls setuid(2) we do not want any 571 * future processes to honor the potentially un-safe variables. 572 */ 573 if (!trust) { 574 if (unsetenv(_LD("PRELOAD")) || unsetenv(_LD("LIBMAP")) || 575 unsetenv(_LD("LIBRARY_PATH")) || unsetenv(_LD("LIBRARY_PATH_FDS")) || 576 unsetenv(_LD("LIBMAP_DISABLE")) || unsetenv(_LD("BIND_NOT")) || 577 unsetenv(_LD("DEBUG")) || unsetenv(_LD("ELF_HINTS_PATH")) || 578 unsetenv(_LD("LOADFLTR")) || unsetenv(_LD("LIBRARY_PATH_RPATH"))) { 579 _rtld_error("environment corrupt; aborting"); 580 rtld_die(); 581 } 582 } 583 ld_debug = getenv(_LD("DEBUG")); 584 if (ld_bind_now == NULL) 585 ld_bind_not = getenv(_LD("BIND_NOT")) != NULL; 586 libmap_disable = getenv(_LD("LIBMAP_DISABLE")) != NULL; 587 libmap_override = getenv(_LD("LIBMAP")); 588 ld_library_path = getenv(_LD("LIBRARY_PATH")); 589 ld_library_dirs = getenv(_LD("LIBRARY_PATH_FDS")); 590 ld_preload = getenv(_LD("PRELOAD")); 591 ld_elf_hints_path = getenv(_LD("ELF_HINTS_PATH")); 592 ld_loadfltr = getenv(_LD("LOADFLTR")) != NULL; 593 library_path_rpath = getenv(_LD("LIBRARY_PATH_RPATH")); 594 if (library_path_rpath != NULL) { 595 if (library_path_rpath[0] == 'y' || 596 library_path_rpath[0] == 'Y' || 597 library_path_rpath[0] == '1') 598 ld_library_path_rpath = true; 599 else 600 ld_library_path_rpath = false; 601 } 602 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 603 (ld_library_path != NULL) || (ld_preload != NULL) || 604 (ld_elf_hints_path != NULL) || ld_loadfltr; 605 ld_tracing = getenv(_LD("TRACE_LOADED_OBJECTS")); 606 ld_utrace = getenv(_LD("UTRACE")); 607 608 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 609 ld_elf_hints_path = ld_elf_hints_default; 610 611 if (ld_debug != NULL && *ld_debug != '\0') 612 debug = 1; 613 dbg("%s is initialized, base address = %p", __progname, 614 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 615 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 616 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 617 618 dbg("initializing thread locks"); 619 lockdflt_init(); 620 621 /* 622 * Load the main program, or process its program header if it is 623 * already loaded. 624 */ 625 if (fd != -1) { /* Load the main program. */ 626 dbg("loading main program"); 627 obj_main = map_object(fd, argv0, NULL); 628 close(fd); 629 if (obj_main == NULL) 630 rtld_die(); 631 max_stack_flags = obj_main->stack_flags; 632 } else { /* Main program already loaded. */ 633 dbg("processing main program's program header"); 634 assert(aux_info[AT_PHDR] != NULL); 635 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 636 assert(aux_info[AT_PHNUM] != NULL); 637 phnum = aux_info[AT_PHNUM]->a_un.a_val; 638 assert(aux_info[AT_PHENT] != NULL); 639 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 640 assert(aux_info[AT_ENTRY] != NULL); 641 imgentry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 642 if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) == NULL) 643 rtld_die(); 644 } 645 646 if (aux_info[AT_EXECPATH] != NULL && fd == -1) { 647 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 648 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 649 if (kexecpath[0] == '/') 650 obj_main->path = kexecpath; 651 else if (getcwd(buf, sizeof(buf)) == NULL || 652 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 653 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 654 obj_main->path = xstrdup(argv0); 655 else 656 obj_main->path = xstrdup(buf); 657 } else { 658 dbg("No AT_EXECPATH or direct exec"); 659 obj_main->path = xstrdup(argv0); 660 } 661 dbg("obj_main path %s", obj_main->path); 662 obj_main->mainprog = true; 663 664 if (aux_info[AT_STACKPROT] != NULL && 665 aux_info[AT_STACKPROT]->a_un.a_val != 0) 666 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 667 668 #ifndef COMPAT_32BIT 669 /* 670 * Get the actual dynamic linker pathname from the executable if 671 * possible. (It should always be possible.) That ensures that 672 * gdb will find the right dynamic linker even if a non-standard 673 * one is being used. 674 */ 675 if (obj_main->interp != NULL && 676 strcmp(obj_main->interp, obj_rtld.path) != 0) { 677 free(obj_rtld.path); 678 obj_rtld.path = xstrdup(obj_main->interp); 679 __progname = obj_rtld.path; 680 } 681 #endif 682 683 if (!digest_dynamic(obj_main, 0)) 684 rtld_die(); 685 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 686 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 687 obj_main->dynsymcount); 688 689 linkmap_add(obj_main); 690 linkmap_add(&obj_rtld); 691 692 /* Link the main program into the list of objects. */ 693 TAILQ_INSERT_HEAD(&obj_list, obj_main, next); 694 obj_count++; 695 obj_loads++; 696 697 /* Initialize a fake symbol for resolving undefined weak references. */ 698 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 699 sym_zero.st_shndx = SHN_UNDEF; 700 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 701 702 if (!libmap_disable) 703 libmap_disable = (bool)lm_init(libmap_override); 704 705 dbg("loading LD_PRELOAD libraries"); 706 if (load_preload_objects() == -1) 707 rtld_die(); 708 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 709 710 dbg("loading needed objects"); 711 if (load_needed_objects(obj_main, ld_tracing != NULL ? RTLD_LO_TRACE : 712 0) == -1) 713 rtld_die(); 714 715 /* Make a list of all objects loaded at startup. */ 716 last_interposer = obj_main; 717 TAILQ_FOREACH(obj, &obj_list, next) { 718 if (obj->marker) 719 continue; 720 if (obj->z_interpose && obj != obj_main) { 721 objlist_put_after(&list_main, last_interposer, obj); 722 last_interposer = obj; 723 } else { 724 objlist_push_tail(&list_main, obj); 725 } 726 obj->refcount++; 727 } 728 729 dbg("checking for required versions"); 730 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 731 rtld_die(); 732 733 if (ld_tracing) { /* We're done */ 734 trace_loaded_objects(obj_main); 735 exit(0); 736 } 737 738 if (getenv(_LD("DUMP_REL_PRE")) != NULL) { 739 dump_relocations(obj_main); 740 exit (0); 741 } 742 743 /* 744 * Processing tls relocations requires having the tls offsets 745 * initialized. Prepare offsets before starting initial 746 * relocation processing. 747 */ 748 dbg("initializing initial thread local storage offsets"); 749 STAILQ_FOREACH(entry, &list_main, link) { 750 /* 751 * Allocate all the initial objects out of the static TLS 752 * block even if they didn't ask for it. 753 */ 754 allocate_tls_offset(entry->obj); 755 } 756 757 if (relocate_objects(obj_main, 758 ld_bind_now != NULL && *ld_bind_now != '\0', 759 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 760 rtld_die(); 761 762 dbg("doing copy relocations"); 763 if (do_copy_relocations(obj_main) == -1) 764 rtld_die(); 765 766 if (getenv(_LD("DUMP_REL_POST")) != NULL) { 767 dump_relocations(obj_main); 768 exit (0); 769 } 770 771 ifunc_init(aux); 772 773 /* 774 * Setup TLS for main thread. This must be done after the 775 * relocations are processed, since tls initialization section 776 * might be the subject for relocations. 777 */ 778 dbg("initializing initial thread local storage"); 779 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list))); 780 781 dbg("initializing key program variables"); 782 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 783 set_program_var("environ", env); 784 set_program_var("__elf_aux_vector", aux); 785 786 /* Make a list of init functions to call. */ 787 objlist_init(&initlist); 788 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)), 789 preload_tail, &initlist); 790 791 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 792 793 map_stacks_exec(NULL); 794 795 if (!obj_main->crt_no_init) { 796 /* 797 * Make sure we don't call the main program's init and fini 798 * functions for binaries linked with old crt1 which calls 799 * _init itself. 800 */ 801 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 802 obj_main->preinit_array = obj_main->init_array = 803 obj_main->fini_array = (Elf_Addr)NULL; 804 } 805 806 if (direct_exec) { 807 /* Set osrel for direct-execed binary */ 808 mib[0] = CTL_KERN; 809 mib[1] = KERN_PROC; 810 mib[2] = KERN_PROC_OSREL; 811 mib[3] = getpid(); 812 osrel = obj_main->osrel; 813 sz = sizeof(old_osrel); 814 dbg("setting osrel to %d", osrel); 815 (void)sysctl(mib, 4, &old_osrel, &sz, &osrel, sizeof(osrel)); 816 } 817 818 wlock_acquire(rtld_bind_lock, &lockstate); 819 820 dbg("resolving ifuncs"); 821 if (initlist_objects_ifunc(&initlist, ld_bind_now != NULL && 822 *ld_bind_now != '\0', SYMLOOK_EARLY, &lockstate) == -1) 823 rtld_die(); 824 825 rtld_exit_ptr = rtld_exit; 826 if (obj_main->crt_no_init) 827 preinit_main(); 828 objlist_call_init(&initlist, &lockstate); 829 _r_debug_postinit(&obj_main->linkmap); 830 objlist_clear(&initlist); 831 dbg("loading filtees"); 832 TAILQ_FOREACH(obj, &obj_list, next) { 833 if (obj->marker) 834 continue; 835 if (ld_loadfltr || obj->z_loadfltr) 836 load_filtees(obj, 0, &lockstate); 837 } 838 839 dbg("enforcing main obj relro"); 840 if (obj_enforce_relro(obj_main) == -1) 841 rtld_die(); 842 843 lock_release(rtld_bind_lock, &lockstate); 844 845 dbg("transferring control to program entry point = %p", obj_main->entry); 846 847 /* Return the exit procedure and the program entry point. */ 848 *exit_proc = rtld_exit_ptr; 849 *objp = obj_main; 850 return (func_ptr_type) obj_main->entry; 851 } 852 853 void * 854 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 855 { 856 void *ptr; 857 Elf_Addr target; 858 859 ptr = (void *)make_function_pointer(def, obj); 860 target = call_ifunc_resolver(ptr); 861 return ((void *)target); 862 } 863 864 /* 865 * NB: MIPS uses a private version of this function (_mips_rtld_bind). 866 * Changes to this function should be applied there as well. 867 */ 868 Elf_Addr 869 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 870 { 871 const Elf_Rel *rel; 872 const Elf_Sym *def; 873 const Obj_Entry *defobj; 874 Elf_Addr *where; 875 Elf_Addr target; 876 RtldLockState lockstate; 877 878 rlock_acquire(rtld_bind_lock, &lockstate); 879 if (sigsetjmp(lockstate.env, 0) != 0) 880 lock_upgrade(rtld_bind_lock, &lockstate); 881 if (obj->pltrel) 882 rel = (const Elf_Rel *)((const char *)obj->pltrel + reloff); 883 else 884 rel = (const Elf_Rel *)((const char *)obj->pltrela + reloff); 885 886 where = (Elf_Addr *)(obj->relocbase + rel->r_offset); 887 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT, 888 NULL, &lockstate); 889 if (def == NULL) 890 rtld_die(); 891 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 892 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 893 else 894 target = (Elf_Addr)(defobj->relocbase + def->st_value); 895 896 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 897 defobj->strtab + def->st_name, 898 obj->path == NULL ? NULL : basename(obj->path), 899 (void *)target, 900 defobj->path == NULL ? NULL : basename(defobj->path)); 901 902 /* 903 * Write the new contents for the jmpslot. Note that depending on 904 * architecture, the value which we need to return back to the 905 * lazy binding trampoline may or may not be the target 906 * address. The value returned from reloc_jmpslot() is the value 907 * that the trampoline needs. 908 */ 909 target = reloc_jmpslot(where, target, defobj, obj, rel); 910 lock_release(rtld_bind_lock, &lockstate); 911 return target; 912 } 913 914 /* 915 * Error reporting function. Use it like printf. If formats the message 916 * into a buffer, and sets things up so that the next call to dlerror() 917 * will return the message. 918 */ 919 void 920 _rtld_error(const char *fmt, ...) 921 { 922 static char buf[512]; 923 va_list ap; 924 925 va_start(ap, fmt); 926 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 927 error_message = buf; 928 va_end(ap); 929 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, error_message); 930 } 931 932 /* 933 * Return a dynamically-allocated copy of the current error message, if any. 934 */ 935 static char * 936 errmsg_save(void) 937 { 938 return error_message == NULL ? NULL : xstrdup(error_message); 939 } 940 941 /* 942 * Restore the current error message from a copy which was previously saved 943 * by errmsg_save(). The copy is freed. 944 */ 945 static void 946 errmsg_restore(char *saved_msg) 947 { 948 if (saved_msg == NULL) 949 error_message = NULL; 950 else { 951 _rtld_error("%s", saved_msg); 952 free(saved_msg); 953 } 954 } 955 956 static const char * 957 basename(const char *name) 958 { 959 const char *p = strrchr(name, '/'); 960 return p != NULL ? p + 1 : name; 961 } 962 963 static struct utsname uts; 964 965 static char * 966 origin_subst_one(Obj_Entry *obj, char *real, const char *kw, 967 const char *subst, bool may_free) 968 { 969 char *p, *p1, *res, *resp; 970 int subst_len, kw_len, subst_count, old_len, new_len; 971 972 kw_len = strlen(kw); 973 974 /* 975 * First, count the number of the keyword occurrences, to 976 * preallocate the final string. 977 */ 978 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 979 p1 = strstr(p, kw); 980 if (p1 == NULL) 981 break; 982 } 983 984 /* 985 * If the keyword is not found, just return. 986 * 987 * Return non-substituted string if resolution failed. We 988 * cannot do anything more reasonable, the failure mode of the 989 * caller is unresolved library anyway. 990 */ 991 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj))) 992 return (may_free ? real : xstrdup(real)); 993 if (obj != NULL) 994 subst = obj->origin_path; 995 996 /* 997 * There is indeed something to substitute. Calculate the 998 * length of the resulting string, and allocate it. 999 */ 1000 subst_len = strlen(subst); 1001 old_len = strlen(real); 1002 new_len = old_len + (subst_len - kw_len) * subst_count; 1003 res = xmalloc(new_len + 1); 1004 1005 /* 1006 * Now, execute the substitution loop. 1007 */ 1008 for (p = real, resp = res, *resp = '\0';;) { 1009 p1 = strstr(p, kw); 1010 if (p1 != NULL) { 1011 /* Copy the prefix before keyword. */ 1012 memcpy(resp, p, p1 - p); 1013 resp += p1 - p; 1014 /* Keyword replacement. */ 1015 memcpy(resp, subst, subst_len); 1016 resp += subst_len; 1017 *resp = '\0'; 1018 p = p1 + kw_len; 1019 } else 1020 break; 1021 } 1022 1023 /* Copy to the end of string and finish. */ 1024 strcat(resp, p); 1025 if (may_free) 1026 free(real); 1027 return (res); 1028 } 1029 1030 static char * 1031 origin_subst(Obj_Entry *obj, const char *real) 1032 { 1033 char *res1, *res2, *res3, *res4; 1034 1035 if (obj == NULL || !trust) 1036 return (xstrdup(real)); 1037 if (uts.sysname[0] == '\0') { 1038 if (uname(&uts) != 0) { 1039 _rtld_error("utsname failed: %d", errno); 1040 return (NULL); 1041 } 1042 } 1043 /* __DECONST is safe here since without may_free real is unchanged */ 1044 res1 = origin_subst_one(obj, __DECONST(char *, real), "$ORIGIN", NULL, 1045 false); 1046 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true); 1047 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true); 1048 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true); 1049 return (res4); 1050 } 1051 1052 void 1053 rtld_die(void) 1054 { 1055 const char *msg = dlerror(); 1056 1057 if (msg == NULL) 1058 msg = "Fatal error"; 1059 rtld_fdputstr(STDERR_FILENO, _BASENAME_RTLD ": "); 1060 rtld_fdputstr(STDERR_FILENO, msg); 1061 rtld_fdputchar(STDERR_FILENO, '\n'); 1062 _exit(1); 1063 } 1064 1065 /* 1066 * Process a shared object's DYNAMIC section, and save the important 1067 * information in its Obj_Entry structure. 1068 */ 1069 static void 1070 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 1071 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 1072 { 1073 const Elf_Dyn *dynp; 1074 Needed_Entry **needed_tail = &obj->needed; 1075 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 1076 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 1077 const Elf_Hashelt *hashtab; 1078 const Elf32_Word *hashval; 1079 Elf32_Word bkt, nmaskwords; 1080 int bloom_size32; 1081 int plttype = DT_REL; 1082 1083 *dyn_rpath = NULL; 1084 *dyn_soname = NULL; 1085 *dyn_runpath = NULL; 1086 1087 obj->bind_now = false; 1088 dynp = obj->dynamic; 1089 if (dynp == NULL) 1090 return; 1091 for (; dynp->d_tag != DT_NULL; dynp++) { 1092 switch (dynp->d_tag) { 1093 1094 case DT_REL: 1095 obj->rel = (const Elf_Rel *)(obj->relocbase + dynp->d_un.d_ptr); 1096 break; 1097 1098 case DT_RELSZ: 1099 obj->relsize = dynp->d_un.d_val; 1100 break; 1101 1102 case DT_RELENT: 1103 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 1104 break; 1105 1106 case DT_JMPREL: 1107 obj->pltrel = (const Elf_Rel *) 1108 (obj->relocbase + dynp->d_un.d_ptr); 1109 break; 1110 1111 case DT_PLTRELSZ: 1112 obj->pltrelsize = dynp->d_un.d_val; 1113 break; 1114 1115 case DT_RELA: 1116 obj->rela = (const Elf_Rela *)(obj->relocbase + dynp->d_un.d_ptr); 1117 break; 1118 1119 case DT_RELASZ: 1120 obj->relasize = dynp->d_un.d_val; 1121 break; 1122 1123 case DT_RELAENT: 1124 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 1125 break; 1126 1127 case DT_PLTREL: 1128 plttype = dynp->d_un.d_val; 1129 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 1130 break; 1131 1132 case DT_SYMTAB: 1133 obj->symtab = (const Elf_Sym *) 1134 (obj->relocbase + dynp->d_un.d_ptr); 1135 break; 1136 1137 case DT_SYMENT: 1138 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 1139 break; 1140 1141 case DT_STRTAB: 1142 obj->strtab = (const char *)(obj->relocbase + dynp->d_un.d_ptr); 1143 break; 1144 1145 case DT_STRSZ: 1146 obj->strsize = dynp->d_un.d_val; 1147 break; 1148 1149 case DT_VERNEED: 1150 obj->verneed = (const Elf_Verneed *)(obj->relocbase + 1151 dynp->d_un.d_val); 1152 break; 1153 1154 case DT_VERNEEDNUM: 1155 obj->verneednum = dynp->d_un.d_val; 1156 break; 1157 1158 case DT_VERDEF: 1159 obj->verdef = (const Elf_Verdef *)(obj->relocbase + 1160 dynp->d_un.d_val); 1161 break; 1162 1163 case DT_VERDEFNUM: 1164 obj->verdefnum = dynp->d_un.d_val; 1165 break; 1166 1167 case DT_VERSYM: 1168 obj->versyms = (const Elf_Versym *)(obj->relocbase + 1169 dynp->d_un.d_val); 1170 break; 1171 1172 case DT_HASH: 1173 { 1174 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1175 dynp->d_un.d_ptr); 1176 obj->nbuckets = hashtab[0]; 1177 obj->nchains = hashtab[1]; 1178 obj->buckets = hashtab + 2; 1179 obj->chains = obj->buckets + obj->nbuckets; 1180 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 1181 obj->buckets != NULL; 1182 } 1183 break; 1184 1185 case DT_GNU_HASH: 1186 { 1187 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1188 dynp->d_un.d_ptr); 1189 obj->nbuckets_gnu = hashtab[0]; 1190 obj->symndx_gnu = hashtab[1]; 1191 nmaskwords = hashtab[2]; 1192 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1193 obj->maskwords_bm_gnu = nmaskwords - 1; 1194 obj->shift2_gnu = hashtab[3]; 1195 obj->bloom_gnu = (const Elf_Addr *)(hashtab + 4); 1196 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1197 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1198 obj->symndx_gnu; 1199 /* Number of bitmask words is required to be power of 2 */ 1200 obj->valid_hash_gnu = powerof2(nmaskwords) && 1201 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1202 } 1203 break; 1204 1205 case DT_NEEDED: 1206 if (!obj->rtld) { 1207 Needed_Entry *nep = NEW(Needed_Entry); 1208 nep->name = dynp->d_un.d_val; 1209 nep->obj = NULL; 1210 nep->next = NULL; 1211 1212 *needed_tail = nep; 1213 needed_tail = &nep->next; 1214 } 1215 break; 1216 1217 case DT_FILTER: 1218 if (!obj->rtld) { 1219 Needed_Entry *nep = NEW(Needed_Entry); 1220 nep->name = dynp->d_un.d_val; 1221 nep->obj = NULL; 1222 nep->next = NULL; 1223 1224 *needed_filtees_tail = nep; 1225 needed_filtees_tail = &nep->next; 1226 1227 if (obj->linkmap.l_refname == NULL) 1228 obj->linkmap.l_refname = (char *)dynp->d_un.d_val; 1229 } 1230 break; 1231 1232 case DT_AUXILIARY: 1233 if (!obj->rtld) { 1234 Needed_Entry *nep = NEW(Needed_Entry); 1235 nep->name = dynp->d_un.d_val; 1236 nep->obj = NULL; 1237 nep->next = NULL; 1238 1239 *needed_aux_filtees_tail = nep; 1240 needed_aux_filtees_tail = &nep->next; 1241 } 1242 break; 1243 1244 case DT_PLTGOT: 1245 obj->pltgot = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr); 1246 break; 1247 1248 case DT_TEXTREL: 1249 obj->textrel = true; 1250 break; 1251 1252 case DT_SYMBOLIC: 1253 obj->symbolic = true; 1254 break; 1255 1256 case DT_RPATH: 1257 /* 1258 * We have to wait until later to process this, because we 1259 * might not have gotten the address of the string table yet. 1260 */ 1261 *dyn_rpath = dynp; 1262 break; 1263 1264 case DT_SONAME: 1265 *dyn_soname = dynp; 1266 break; 1267 1268 case DT_RUNPATH: 1269 *dyn_runpath = dynp; 1270 break; 1271 1272 case DT_INIT: 1273 obj->init = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1274 break; 1275 1276 case DT_PREINIT_ARRAY: 1277 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1278 break; 1279 1280 case DT_PREINIT_ARRAYSZ: 1281 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1282 break; 1283 1284 case DT_INIT_ARRAY: 1285 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1286 break; 1287 1288 case DT_INIT_ARRAYSZ: 1289 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1290 break; 1291 1292 case DT_FINI: 1293 obj->fini = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1294 break; 1295 1296 case DT_FINI_ARRAY: 1297 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1298 break; 1299 1300 case DT_FINI_ARRAYSZ: 1301 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1302 break; 1303 1304 /* 1305 * Don't process DT_DEBUG on MIPS as the dynamic section 1306 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1307 */ 1308 1309 #ifndef __mips__ 1310 case DT_DEBUG: 1311 if (!early) 1312 dbg("Filling in DT_DEBUG entry"); 1313 (__DECONST(Elf_Dyn *, dynp))->d_un.d_ptr = (Elf_Addr)&r_debug; 1314 break; 1315 #endif 1316 1317 case DT_FLAGS: 1318 if (dynp->d_un.d_val & DF_ORIGIN) 1319 obj->z_origin = true; 1320 if (dynp->d_un.d_val & DF_SYMBOLIC) 1321 obj->symbolic = true; 1322 if (dynp->d_un.d_val & DF_TEXTREL) 1323 obj->textrel = true; 1324 if (dynp->d_un.d_val & DF_BIND_NOW) 1325 obj->bind_now = true; 1326 if (dynp->d_un.d_val & DF_STATIC_TLS) 1327 obj->static_tls = true; 1328 break; 1329 #ifdef __mips__ 1330 case DT_MIPS_LOCAL_GOTNO: 1331 obj->local_gotno = dynp->d_un.d_val; 1332 break; 1333 1334 case DT_MIPS_SYMTABNO: 1335 obj->symtabno = dynp->d_un.d_val; 1336 break; 1337 1338 case DT_MIPS_GOTSYM: 1339 obj->gotsym = dynp->d_un.d_val; 1340 break; 1341 1342 case DT_MIPS_RLD_MAP: 1343 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1344 break; 1345 1346 case DT_MIPS_RLD_MAP_REL: 1347 // The MIPS_RLD_MAP_REL tag stores the offset to the .rld_map 1348 // section relative to the address of the tag itself. 1349 *((Elf_Addr *)(__DECONST(char*, dynp) + dynp->d_un.d_val)) = 1350 (Elf_Addr) &r_debug; 1351 break; 1352 1353 case DT_MIPS_PLTGOT: 1354 obj->mips_pltgot = (Elf_Addr *)(obj->relocbase + 1355 dynp->d_un.d_ptr); 1356 break; 1357 1358 #endif 1359 1360 #ifdef __powerpc__ 1361 #ifdef __powerpc64__ 1362 case DT_PPC64_GLINK: 1363 obj->glink = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1364 break; 1365 #else 1366 case DT_PPC_GOT: 1367 obj->gotptr = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr); 1368 break; 1369 #endif 1370 #endif 1371 1372 case DT_FLAGS_1: 1373 if (dynp->d_un.d_val & DF_1_NOOPEN) 1374 obj->z_noopen = true; 1375 if (dynp->d_un.d_val & DF_1_ORIGIN) 1376 obj->z_origin = true; 1377 if (dynp->d_un.d_val & DF_1_GLOBAL) 1378 obj->z_global = true; 1379 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1380 obj->bind_now = true; 1381 if (dynp->d_un.d_val & DF_1_NODELETE) 1382 obj->z_nodelete = true; 1383 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1384 obj->z_loadfltr = true; 1385 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1386 obj->z_interpose = true; 1387 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1388 obj->z_nodeflib = true; 1389 if (dynp->d_un.d_val & DF_1_PIE) 1390 obj->z_pie = true; 1391 break; 1392 1393 default: 1394 if (!early) { 1395 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1396 (long)dynp->d_tag); 1397 } 1398 break; 1399 } 1400 } 1401 1402 obj->traced = false; 1403 1404 if (plttype == DT_RELA) { 1405 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1406 obj->pltrel = NULL; 1407 obj->pltrelasize = obj->pltrelsize; 1408 obj->pltrelsize = 0; 1409 } 1410 1411 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1412 if (obj->valid_hash_sysv) 1413 obj->dynsymcount = obj->nchains; 1414 else if (obj->valid_hash_gnu) { 1415 obj->dynsymcount = 0; 1416 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1417 if (obj->buckets_gnu[bkt] == 0) 1418 continue; 1419 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1420 do 1421 obj->dynsymcount++; 1422 while ((*hashval++ & 1u) == 0); 1423 } 1424 obj->dynsymcount += obj->symndx_gnu; 1425 } 1426 1427 if (obj->linkmap.l_refname != NULL) 1428 obj->linkmap.l_refname = obj->strtab + (unsigned long)obj-> 1429 linkmap.l_refname; 1430 } 1431 1432 static bool 1433 obj_resolve_origin(Obj_Entry *obj) 1434 { 1435 1436 if (obj->origin_path != NULL) 1437 return (true); 1438 obj->origin_path = xmalloc(PATH_MAX); 1439 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1); 1440 } 1441 1442 static bool 1443 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1444 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1445 { 1446 1447 if (obj->z_origin && !obj_resolve_origin(obj)) 1448 return (false); 1449 1450 if (dyn_runpath != NULL) { 1451 obj->runpath = (const char *)obj->strtab + dyn_runpath->d_un.d_val; 1452 obj->runpath = origin_subst(obj, obj->runpath); 1453 } else if (dyn_rpath != NULL) { 1454 obj->rpath = (const char *)obj->strtab + dyn_rpath->d_un.d_val; 1455 obj->rpath = origin_subst(obj, obj->rpath); 1456 } 1457 if (dyn_soname != NULL) 1458 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1459 return (true); 1460 } 1461 1462 static bool 1463 digest_dynamic(Obj_Entry *obj, int early) 1464 { 1465 const Elf_Dyn *dyn_rpath; 1466 const Elf_Dyn *dyn_soname; 1467 const Elf_Dyn *dyn_runpath; 1468 1469 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1470 return (digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath)); 1471 } 1472 1473 /* 1474 * Process a shared object's program header. This is used only for the 1475 * main program, when the kernel has already loaded the main program 1476 * into memory before calling the dynamic linker. It creates and 1477 * returns an Obj_Entry structure. 1478 */ 1479 static Obj_Entry * 1480 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1481 { 1482 Obj_Entry *obj; 1483 const Elf_Phdr *phlimit = phdr + phnum; 1484 const Elf_Phdr *ph; 1485 Elf_Addr note_start, note_end; 1486 int nsegs = 0; 1487 1488 obj = obj_new(); 1489 for (ph = phdr; ph < phlimit; ph++) { 1490 if (ph->p_type != PT_PHDR) 1491 continue; 1492 1493 obj->phdr = phdr; 1494 obj->phsize = ph->p_memsz; 1495 obj->relocbase = __DECONST(char *, phdr) - ph->p_vaddr; 1496 break; 1497 } 1498 1499 obj->stack_flags = PF_X | PF_R | PF_W; 1500 1501 for (ph = phdr; ph < phlimit; ph++) { 1502 switch (ph->p_type) { 1503 1504 case PT_INTERP: 1505 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1506 break; 1507 1508 case PT_LOAD: 1509 if (nsegs == 0) { /* First load segment */ 1510 obj->vaddrbase = trunc_page(ph->p_vaddr); 1511 obj->mapbase = obj->vaddrbase + obj->relocbase; 1512 } else { /* Last load segment */ 1513 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1514 obj->vaddrbase; 1515 } 1516 nsegs++; 1517 break; 1518 1519 case PT_DYNAMIC: 1520 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1521 break; 1522 1523 case PT_TLS: 1524 obj->tlsindex = 1; 1525 obj->tlssize = ph->p_memsz; 1526 obj->tlsalign = ph->p_align; 1527 obj->tlsinitsize = ph->p_filesz; 1528 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1529 obj->tlspoffset = ph->p_offset; 1530 break; 1531 1532 case PT_GNU_STACK: 1533 obj->stack_flags = ph->p_flags; 1534 break; 1535 1536 case PT_GNU_RELRO: 1537 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1538 obj->relro_size = round_page(ph->p_memsz); 1539 break; 1540 1541 case PT_NOTE: 1542 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1543 note_end = note_start + ph->p_filesz; 1544 digest_notes(obj, note_start, note_end); 1545 break; 1546 } 1547 } 1548 if (nsegs < 1) { 1549 _rtld_error("%s: too few PT_LOAD segments", path); 1550 return NULL; 1551 } 1552 1553 obj->entry = entry; 1554 return obj; 1555 } 1556 1557 void 1558 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1559 { 1560 const Elf_Note *note; 1561 const char *note_name; 1562 uintptr_t p; 1563 1564 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1565 note = (const Elf_Note *)((const char *)(note + 1) + 1566 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1567 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1568 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1569 note->n_descsz != sizeof(int32_t)) 1570 continue; 1571 if (note->n_type != NT_FREEBSD_ABI_TAG && 1572 note->n_type != NT_FREEBSD_FEATURE_CTL && 1573 note->n_type != NT_FREEBSD_NOINIT_TAG) 1574 continue; 1575 note_name = (const char *)(note + 1); 1576 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1577 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1578 continue; 1579 switch (note->n_type) { 1580 case NT_FREEBSD_ABI_TAG: 1581 /* FreeBSD osrel note */ 1582 p = (uintptr_t)(note + 1); 1583 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1584 obj->osrel = *(const int32_t *)(p); 1585 dbg("note osrel %d", obj->osrel); 1586 break; 1587 case NT_FREEBSD_FEATURE_CTL: 1588 /* FreeBSD ABI feature control note */ 1589 p = (uintptr_t)(note + 1); 1590 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1591 obj->fctl0 = *(const uint32_t *)(p); 1592 dbg("note fctl0 %#x", obj->fctl0); 1593 break; 1594 case NT_FREEBSD_NOINIT_TAG: 1595 /* FreeBSD 'crt does not call init' note */ 1596 obj->crt_no_init = true; 1597 dbg("note crt_no_init"); 1598 break; 1599 } 1600 } 1601 } 1602 1603 static Obj_Entry * 1604 dlcheck(void *handle) 1605 { 1606 Obj_Entry *obj; 1607 1608 TAILQ_FOREACH(obj, &obj_list, next) { 1609 if (obj == (Obj_Entry *) handle) 1610 break; 1611 } 1612 1613 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1614 _rtld_error("Invalid shared object handle %p", handle); 1615 return NULL; 1616 } 1617 return obj; 1618 } 1619 1620 /* 1621 * If the given object is already in the donelist, return true. Otherwise 1622 * add the object to the list and return false. 1623 */ 1624 static bool 1625 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1626 { 1627 unsigned int i; 1628 1629 for (i = 0; i < dlp->num_used; i++) 1630 if (dlp->objs[i] == obj) 1631 return true; 1632 /* 1633 * Our donelist allocation should always be sufficient. But if 1634 * our threads locking isn't working properly, more shared objects 1635 * could have been loaded since we allocated the list. That should 1636 * never happen, but we'll handle it properly just in case it does. 1637 */ 1638 if (dlp->num_used < dlp->num_alloc) 1639 dlp->objs[dlp->num_used++] = obj; 1640 return false; 1641 } 1642 1643 /* 1644 * Hash function for symbol table lookup. Don't even think about changing 1645 * this. It is specified by the System V ABI. 1646 */ 1647 unsigned long 1648 elf_hash(const char *name) 1649 { 1650 const unsigned char *p = (const unsigned char *) name; 1651 unsigned long h = 0; 1652 unsigned long g; 1653 1654 while (*p != '\0') { 1655 h = (h << 4) + *p++; 1656 if ((g = h & 0xf0000000) != 0) 1657 h ^= g >> 24; 1658 h &= ~g; 1659 } 1660 return h; 1661 } 1662 1663 /* 1664 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1665 * unsigned in case it's implemented with a wider type. 1666 */ 1667 static uint32_t 1668 gnu_hash(const char *s) 1669 { 1670 uint32_t h; 1671 unsigned char c; 1672 1673 h = 5381; 1674 for (c = *s; c != '\0'; c = *++s) 1675 h = h * 33 + c; 1676 return (h & 0xffffffff); 1677 } 1678 1679 1680 /* 1681 * Find the library with the given name, and return its full pathname. 1682 * The returned string is dynamically allocated. Generates an error 1683 * message and returns NULL if the library cannot be found. 1684 * 1685 * If the second argument is non-NULL, then it refers to an already- 1686 * loaded shared object, whose library search path will be searched. 1687 * 1688 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1689 * descriptor (which is close-on-exec) will be passed out via the third 1690 * argument. 1691 * 1692 * The search order is: 1693 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1694 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1695 * LD_LIBRARY_PATH 1696 * DT_RUNPATH in the referencing file 1697 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1698 * from list) 1699 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1700 * 1701 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1702 */ 1703 static char * 1704 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1705 { 1706 char *pathname, *refobj_path; 1707 const char *name; 1708 bool nodeflib, objgiven; 1709 1710 objgiven = refobj != NULL; 1711 1712 if (libmap_disable || !objgiven || 1713 (name = lm_find(refobj->path, xname)) == NULL) 1714 name = xname; 1715 1716 if (strchr(name, '/') != NULL) { /* Hard coded pathname */ 1717 if (name[0] != '/' && !trust) { 1718 _rtld_error("Absolute pathname required " 1719 "for shared object \"%s\"", name); 1720 return (NULL); 1721 } 1722 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1723 __DECONST(char *, name))); 1724 } 1725 1726 dbg(" Searching for \"%s\"", name); 1727 refobj_path = objgiven ? refobj->path : NULL; 1728 1729 /* 1730 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1731 * back to pre-conforming behaviour if user requested so with 1732 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1733 * nodeflib. 1734 */ 1735 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1736 pathname = search_library_path(name, ld_library_path, 1737 refobj_path, fdp); 1738 if (pathname != NULL) 1739 return (pathname); 1740 if (refobj != NULL) { 1741 pathname = search_library_path(name, refobj->rpath, 1742 refobj_path, fdp); 1743 if (pathname != NULL) 1744 return (pathname); 1745 } 1746 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1747 if (pathname != NULL) 1748 return (pathname); 1749 pathname = search_library_path(name, gethints(false), 1750 refobj_path, fdp); 1751 if (pathname != NULL) 1752 return (pathname); 1753 pathname = search_library_path(name, ld_standard_library_path, 1754 refobj_path, fdp); 1755 if (pathname != NULL) 1756 return (pathname); 1757 } else { 1758 nodeflib = objgiven ? refobj->z_nodeflib : false; 1759 if (objgiven) { 1760 pathname = search_library_path(name, refobj->rpath, 1761 refobj->path, fdp); 1762 if (pathname != NULL) 1763 return (pathname); 1764 } 1765 if (objgiven && refobj->runpath == NULL && refobj != obj_main) { 1766 pathname = search_library_path(name, obj_main->rpath, 1767 refobj_path, fdp); 1768 if (pathname != NULL) 1769 return (pathname); 1770 } 1771 pathname = search_library_path(name, ld_library_path, 1772 refobj_path, fdp); 1773 if (pathname != NULL) 1774 return (pathname); 1775 if (objgiven) { 1776 pathname = search_library_path(name, refobj->runpath, 1777 refobj_path, fdp); 1778 if (pathname != NULL) 1779 return (pathname); 1780 } 1781 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1782 if (pathname != NULL) 1783 return (pathname); 1784 pathname = search_library_path(name, gethints(nodeflib), 1785 refobj_path, fdp); 1786 if (pathname != NULL) 1787 return (pathname); 1788 if (objgiven && !nodeflib) { 1789 pathname = search_library_path(name, 1790 ld_standard_library_path, refobj_path, fdp); 1791 if (pathname != NULL) 1792 return (pathname); 1793 } 1794 } 1795 1796 if (objgiven && refobj->path != NULL) { 1797 _rtld_error("Shared object \"%s\" not found, " 1798 "required by \"%s\"", name, basename(refobj->path)); 1799 } else { 1800 _rtld_error("Shared object \"%s\" not found", name); 1801 } 1802 return (NULL); 1803 } 1804 1805 /* 1806 * Given a symbol number in a referencing object, find the corresponding 1807 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1808 * no definition was found. Returns a pointer to the Obj_Entry of the 1809 * defining object via the reference parameter DEFOBJ_OUT. 1810 */ 1811 const Elf_Sym * 1812 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1813 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1814 RtldLockState *lockstate) 1815 { 1816 const Elf_Sym *ref; 1817 const Elf_Sym *def; 1818 const Obj_Entry *defobj; 1819 const Ver_Entry *ve; 1820 SymLook req; 1821 const char *name; 1822 int res; 1823 1824 /* 1825 * If we have already found this symbol, get the information from 1826 * the cache. 1827 */ 1828 if (symnum >= refobj->dynsymcount) 1829 return NULL; /* Bad object */ 1830 if (cache != NULL && cache[symnum].sym != NULL) { 1831 *defobj_out = cache[symnum].obj; 1832 return cache[symnum].sym; 1833 } 1834 1835 ref = refobj->symtab + symnum; 1836 name = refobj->strtab + ref->st_name; 1837 def = NULL; 1838 defobj = NULL; 1839 ve = NULL; 1840 1841 /* 1842 * We don't have to do a full scale lookup if the symbol is local. 1843 * We know it will bind to the instance in this load module; to 1844 * which we already have a pointer (ie ref). By not doing a lookup, 1845 * we not only improve performance, but it also avoids unresolvable 1846 * symbols when local symbols are not in the hash table. This has 1847 * been seen with the ia64 toolchain. 1848 */ 1849 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1850 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1851 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1852 symnum); 1853 } 1854 symlook_init(&req, name); 1855 req.flags = flags; 1856 ve = req.ventry = fetch_ventry(refobj, symnum); 1857 req.lockstate = lockstate; 1858 res = symlook_default(&req, refobj); 1859 if (res == 0) { 1860 def = req.sym_out; 1861 defobj = req.defobj_out; 1862 } 1863 } else { 1864 def = ref; 1865 defobj = refobj; 1866 } 1867 1868 /* 1869 * If we found no definition and the reference is weak, treat the 1870 * symbol as having the value zero. 1871 */ 1872 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1873 def = &sym_zero; 1874 defobj = obj_main; 1875 } 1876 1877 if (def != NULL) { 1878 *defobj_out = defobj; 1879 /* Record the information in the cache to avoid subsequent lookups. */ 1880 if (cache != NULL) { 1881 cache[symnum].sym = def; 1882 cache[symnum].obj = defobj; 1883 } 1884 } else { 1885 if (refobj != &obj_rtld) 1886 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name, 1887 ve != NULL ? "@" : "", ve != NULL ? ve->name : ""); 1888 } 1889 return def; 1890 } 1891 1892 /* 1893 * Return the search path from the ldconfig hints file, reading it if 1894 * necessary. If nostdlib is true, then the default search paths are 1895 * not added to result. 1896 * 1897 * Returns NULL if there are problems with the hints file, 1898 * or if the search path there is empty. 1899 */ 1900 static const char * 1901 gethints(bool nostdlib) 1902 { 1903 static char *filtered_path; 1904 static const char *hints; 1905 static struct elfhints_hdr hdr; 1906 struct fill_search_info_args sargs, hargs; 1907 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1908 struct dl_serpath *SLPpath, *hintpath; 1909 char *p; 1910 struct stat hint_stat; 1911 unsigned int SLPndx, hintndx, fndx, fcount; 1912 int fd; 1913 size_t flen; 1914 uint32_t dl; 1915 bool skip; 1916 1917 /* First call, read the hints file */ 1918 if (hints == NULL) { 1919 /* Keep from trying again in case the hints file is bad. */ 1920 hints = ""; 1921 1922 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1923 return (NULL); 1924 1925 /* 1926 * Check of hdr.dirlistlen value against type limit 1927 * intends to pacify static analyzers. Further 1928 * paranoia leads to checks that dirlist is fully 1929 * contained in the file range. 1930 */ 1931 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1932 hdr.magic != ELFHINTS_MAGIC || 1933 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 || 1934 fstat(fd, &hint_stat) == -1) { 1935 cleanup1: 1936 close(fd); 1937 hdr.dirlistlen = 0; 1938 return (NULL); 1939 } 1940 dl = hdr.strtab; 1941 if (dl + hdr.dirlist < dl) 1942 goto cleanup1; 1943 dl += hdr.dirlist; 1944 if (dl + hdr.dirlistlen < dl) 1945 goto cleanup1; 1946 dl += hdr.dirlistlen; 1947 if (dl > hint_stat.st_size) 1948 goto cleanup1; 1949 p = xmalloc(hdr.dirlistlen + 1); 1950 if (pread(fd, p, hdr.dirlistlen + 1, 1951 hdr.strtab + hdr.dirlist) != (ssize_t)hdr.dirlistlen + 1 || 1952 p[hdr.dirlistlen] != '\0') { 1953 free(p); 1954 goto cleanup1; 1955 } 1956 hints = p; 1957 close(fd); 1958 } 1959 1960 /* 1961 * If caller agreed to receive list which includes the default 1962 * paths, we are done. Otherwise, if we still did not 1963 * calculated filtered result, do it now. 1964 */ 1965 if (!nostdlib) 1966 return (hints[0] != '\0' ? hints : NULL); 1967 if (filtered_path != NULL) 1968 goto filt_ret; 1969 1970 /* 1971 * Obtain the list of all configured search paths, and the 1972 * list of the default paths. 1973 * 1974 * First estimate the size of the results. 1975 */ 1976 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1977 smeta.dls_cnt = 0; 1978 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1979 hmeta.dls_cnt = 0; 1980 1981 sargs.request = RTLD_DI_SERINFOSIZE; 1982 sargs.serinfo = &smeta; 1983 hargs.request = RTLD_DI_SERINFOSIZE; 1984 hargs.serinfo = &hmeta; 1985 1986 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 1987 &sargs); 1988 path_enumerate(hints, fill_search_info, NULL, &hargs); 1989 1990 SLPinfo = xmalloc(smeta.dls_size); 1991 hintinfo = xmalloc(hmeta.dls_size); 1992 1993 /* 1994 * Next fetch both sets of paths. 1995 */ 1996 sargs.request = RTLD_DI_SERINFO; 1997 sargs.serinfo = SLPinfo; 1998 sargs.serpath = &SLPinfo->dls_serpath[0]; 1999 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 2000 2001 hargs.request = RTLD_DI_SERINFO; 2002 hargs.serinfo = hintinfo; 2003 hargs.serpath = &hintinfo->dls_serpath[0]; 2004 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 2005 2006 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 2007 &sargs); 2008 path_enumerate(hints, fill_search_info, NULL, &hargs); 2009 2010 /* 2011 * Now calculate the difference between two sets, by excluding 2012 * standard paths from the full set. 2013 */ 2014 fndx = 0; 2015 fcount = 0; 2016 filtered_path = xmalloc(hdr.dirlistlen + 1); 2017 hintpath = &hintinfo->dls_serpath[0]; 2018 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 2019 skip = false; 2020 SLPpath = &SLPinfo->dls_serpath[0]; 2021 /* 2022 * Check each standard path against current. 2023 */ 2024 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 2025 /* matched, skip the path */ 2026 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 2027 skip = true; 2028 break; 2029 } 2030 } 2031 if (skip) 2032 continue; 2033 /* 2034 * Not matched against any standard path, add the path 2035 * to result. Separate consequtive paths with ':'. 2036 */ 2037 if (fcount > 0) { 2038 filtered_path[fndx] = ':'; 2039 fndx++; 2040 } 2041 fcount++; 2042 flen = strlen(hintpath->dls_name); 2043 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 2044 fndx += flen; 2045 } 2046 filtered_path[fndx] = '\0'; 2047 2048 free(SLPinfo); 2049 free(hintinfo); 2050 2051 filt_ret: 2052 return (filtered_path[0] != '\0' ? filtered_path : NULL); 2053 } 2054 2055 static void 2056 init_dag(Obj_Entry *root) 2057 { 2058 const Needed_Entry *needed; 2059 const Objlist_Entry *elm; 2060 DoneList donelist; 2061 2062 if (root->dag_inited) 2063 return; 2064 donelist_init(&donelist); 2065 2066 /* Root object belongs to own DAG. */ 2067 objlist_push_tail(&root->dldags, root); 2068 objlist_push_tail(&root->dagmembers, root); 2069 donelist_check(&donelist, root); 2070 2071 /* 2072 * Add dependencies of root object to DAG in breadth order 2073 * by exploiting the fact that each new object get added 2074 * to the tail of the dagmembers list. 2075 */ 2076 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2077 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 2078 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 2079 continue; 2080 objlist_push_tail(&needed->obj->dldags, root); 2081 objlist_push_tail(&root->dagmembers, needed->obj); 2082 } 2083 } 2084 root->dag_inited = true; 2085 } 2086 2087 static void 2088 init_marker(Obj_Entry *marker) 2089 { 2090 2091 bzero(marker, sizeof(*marker)); 2092 marker->marker = true; 2093 } 2094 2095 Obj_Entry * 2096 globallist_curr(const Obj_Entry *obj) 2097 { 2098 2099 for (;;) { 2100 if (obj == NULL) 2101 return (NULL); 2102 if (!obj->marker) 2103 return (__DECONST(Obj_Entry *, obj)); 2104 obj = TAILQ_PREV(obj, obj_entry_q, next); 2105 } 2106 } 2107 2108 Obj_Entry * 2109 globallist_next(const Obj_Entry *obj) 2110 { 2111 2112 for (;;) { 2113 obj = TAILQ_NEXT(obj, next); 2114 if (obj == NULL) 2115 return (NULL); 2116 if (!obj->marker) 2117 return (__DECONST(Obj_Entry *, obj)); 2118 } 2119 } 2120 2121 /* Prevent the object from being unmapped while the bind lock is dropped. */ 2122 static void 2123 hold_object(Obj_Entry *obj) 2124 { 2125 2126 obj->holdcount++; 2127 } 2128 2129 static void 2130 unhold_object(Obj_Entry *obj) 2131 { 2132 2133 assert(obj->holdcount > 0); 2134 if (--obj->holdcount == 0 && obj->unholdfree) 2135 release_object(obj); 2136 } 2137 2138 static void 2139 process_z(Obj_Entry *root) 2140 { 2141 const Objlist_Entry *elm; 2142 Obj_Entry *obj; 2143 2144 /* 2145 * Walk over object DAG and process every dependent object 2146 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 2147 * to grow their own DAG. 2148 * 2149 * For DF_1_GLOBAL, DAG is required for symbol lookups in 2150 * symlook_global() to work. 2151 * 2152 * For DF_1_NODELETE, the DAG should have its reference upped. 2153 */ 2154 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2155 obj = elm->obj; 2156 if (obj == NULL) 2157 continue; 2158 if (obj->z_nodelete && !obj->ref_nodel) { 2159 dbg("obj %s -z nodelete", obj->path); 2160 init_dag(obj); 2161 ref_dag(obj); 2162 obj->ref_nodel = true; 2163 } 2164 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 2165 dbg("obj %s -z global", obj->path); 2166 objlist_push_tail(&list_global, obj); 2167 init_dag(obj); 2168 } 2169 } 2170 } 2171 2172 static void 2173 parse_rtld_phdr(Obj_Entry *obj) 2174 { 2175 const Elf_Phdr *ph; 2176 Elf_Addr note_start, note_end; 2177 2178 obj->stack_flags = PF_X | PF_R | PF_W; 2179 for (ph = obj->phdr; (const char *)ph < (const char *)obj->phdr + 2180 obj->phsize; ph++) { 2181 switch (ph->p_type) { 2182 case PT_GNU_STACK: 2183 obj->stack_flags = ph->p_flags; 2184 break; 2185 case PT_GNU_RELRO: 2186 obj->relro_page = obj->relocbase + 2187 trunc_page(ph->p_vaddr); 2188 obj->relro_size = round_page(ph->p_memsz); 2189 break; 2190 case PT_NOTE: 2191 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 2192 note_end = note_start + ph->p_filesz; 2193 digest_notes(obj, note_start, note_end); 2194 break; 2195 } 2196 } 2197 } 2198 2199 /* 2200 * Initialize the dynamic linker. The argument is the address at which 2201 * the dynamic linker has been mapped into memory. The primary task of 2202 * this function is to relocate the dynamic linker. 2203 */ 2204 static void 2205 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 2206 { 2207 Obj_Entry objtmp; /* Temporary rtld object */ 2208 const Elf_Ehdr *ehdr; 2209 const Elf_Dyn *dyn_rpath; 2210 const Elf_Dyn *dyn_soname; 2211 const Elf_Dyn *dyn_runpath; 2212 2213 #ifdef RTLD_INIT_PAGESIZES_EARLY 2214 /* The page size is required by the dynamic memory allocator. */ 2215 init_pagesizes(aux_info); 2216 #endif 2217 2218 /* 2219 * Conjure up an Obj_Entry structure for the dynamic linker. 2220 * 2221 * The "path" member can't be initialized yet because string constants 2222 * cannot yet be accessed. Below we will set it correctly. 2223 */ 2224 memset(&objtmp, 0, sizeof(objtmp)); 2225 objtmp.path = NULL; 2226 objtmp.rtld = true; 2227 objtmp.mapbase = mapbase; 2228 #ifdef PIC 2229 objtmp.relocbase = mapbase; 2230 #endif 2231 2232 objtmp.dynamic = rtld_dynamic(&objtmp); 2233 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 2234 assert(objtmp.needed == NULL); 2235 #if !defined(__mips__) 2236 /* MIPS has a bogus DT_TEXTREL. */ 2237 assert(!objtmp.textrel); 2238 #endif 2239 /* 2240 * Temporarily put the dynamic linker entry into the object list, so 2241 * that symbols can be found. 2242 */ 2243 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 2244 2245 ehdr = (Elf_Ehdr *)mapbase; 2246 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 2247 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 2248 2249 /* Initialize the object list. */ 2250 TAILQ_INIT(&obj_list); 2251 2252 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 2253 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 2254 2255 #ifndef RTLD_INIT_PAGESIZES_EARLY 2256 /* The page size is required by the dynamic memory allocator. */ 2257 init_pagesizes(aux_info); 2258 #endif 2259 2260 if (aux_info[AT_OSRELDATE] != NULL) 2261 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 2262 2263 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 2264 2265 /* Replace the path with a dynamically allocated copy. */ 2266 obj_rtld.path = xstrdup(ld_path_rtld); 2267 2268 parse_rtld_phdr(&obj_rtld); 2269 obj_enforce_relro(&obj_rtld); 2270 2271 r_debug.r_version = R_DEBUG_VERSION; 2272 r_debug.r_brk = r_debug_state; 2273 r_debug.r_state = RT_CONSISTENT; 2274 r_debug.r_ldbase = obj_rtld.relocbase; 2275 } 2276 2277 /* 2278 * Retrieve the array of supported page sizes. The kernel provides the page 2279 * sizes in increasing order. 2280 */ 2281 static void 2282 init_pagesizes(Elf_Auxinfo **aux_info) 2283 { 2284 static size_t psa[MAXPAGESIZES]; 2285 int mib[2]; 2286 size_t len, size; 2287 2288 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 2289 NULL) { 2290 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 2291 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 2292 } else { 2293 len = 2; 2294 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 2295 size = sizeof(psa); 2296 else { 2297 /* As a fallback, retrieve the base page size. */ 2298 size = sizeof(psa[0]); 2299 if (aux_info[AT_PAGESZ] != NULL) { 2300 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 2301 goto psa_filled; 2302 } else { 2303 mib[0] = CTL_HW; 2304 mib[1] = HW_PAGESIZE; 2305 len = 2; 2306 } 2307 } 2308 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 2309 _rtld_error("sysctl for hw.pagesize(s) failed"); 2310 rtld_die(); 2311 } 2312 psa_filled: 2313 pagesizes = psa; 2314 } 2315 npagesizes = size / sizeof(pagesizes[0]); 2316 /* Discard any invalid entries at the end of the array. */ 2317 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 2318 npagesizes--; 2319 } 2320 2321 /* 2322 * Add the init functions from a needed object list (and its recursive 2323 * needed objects) to "list". This is not used directly; it is a helper 2324 * function for initlist_add_objects(). The write lock must be held 2325 * when this function is called. 2326 */ 2327 static void 2328 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 2329 { 2330 /* Recursively process the successor needed objects. */ 2331 if (needed->next != NULL) 2332 initlist_add_neededs(needed->next, list); 2333 2334 /* Process the current needed object. */ 2335 if (needed->obj != NULL) 2336 initlist_add_objects(needed->obj, needed->obj, list); 2337 } 2338 2339 /* 2340 * Scan all of the DAGs rooted in the range of objects from "obj" to 2341 * "tail" and add their init functions to "list". This recurses over 2342 * the DAGs and ensure the proper init ordering such that each object's 2343 * needed libraries are initialized before the object itself. At the 2344 * same time, this function adds the objects to the global finalization 2345 * list "list_fini" in the opposite order. The write lock must be 2346 * held when this function is called. 2347 */ 2348 static void 2349 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2350 { 2351 Obj_Entry *nobj; 2352 2353 if (obj->init_scanned || obj->init_done) 2354 return; 2355 obj->init_scanned = true; 2356 2357 /* Recursively process the successor objects. */ 2358 nobj = globallist_next(obj); 2359 if (nobj != NULL && obj != tail) 2360 initlist_add_objects(nobj, tail, list); 2361 2362 /* Recursively process the needed objects. */ 2363 if (obj->needed != NULL) 2364 initlist_add_neededs(obj->needed, list); 2365 if (obj->needed_filtees != NULL) 2366 initlist_add_neededs(obj->needed_filtees, list); 2367 if (obj->needed_aux_filtees != NULL) 2368 initlist_add_neededs(obj->needed_aux_filtees, list); 2369 2370 /* Add the object to the init list. */ 2371 objlist_push_tail(list, obj); 2372 2373 /* Add the object to the global fini list in the reverse order. */ 2374 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2375 && !obj->on_fini_list) { 2376 objlist_push_head(&list_fini, obj); 2377 obj->on_fini_list = true; 2378 } 2379 } 2380 2381 #ifndef FPTR_TARGET 2382 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 2383 #endif 2384 2385 static void 2386 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate) 2387 { 2388 Needed_Entry *needed, *needed1; 2389 2390 for (needed = n; needed != NULL; needed = needed->next) { 2391 if (needed->obj != NULL) { 2392 dlclose_locked(needed->obj, lockstate); 2393 needed->obj = NULL; 2394 } 2395 } 2396 for (needed = n; needed != NULL; needed = needed1) { 2397 needed1 = needed->next; 2398 free(needed); 2399 } 2400 } 2401 2402 static void 2403 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate) 2404 { 2405 2406 free_needed_filtees(obj->needed_filtees, lockstate); 2407 obj->needed_filtees = NULL; 2408 free_needed_filtees(obj->needed_aux_filtees, lockstate); 2409 obj->needed_aux_filtees = NULL; 2410 obj->filtees_loaded = false; 2411 } 2412 2413 static void 2414 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2415 RtldLockState *lockstate) 2416 { 2417 2418 for (; needed != NULL; needed = needed->next) { 2419 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2420 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2421 RTLD_LOCAL, lockstate); 2422 } 2423 } 2424 2425 static void 2426 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2427 { 2428 2429 lock_restart_for_upgrade(lockstate); 2430 if (!obj->filtees_loaded) { 2431 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2432 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2433 obj->filtees_loaded = true; 2434 } 2435 } 2436 2437 static int 2438 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2439 { 2440 Obj_Entry *obj1; 2441 2442 for (; needed != NULL; needed = needed->next) { 2443 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2444 flags & ~RTLD_LO_NOLOAD); 2445 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2446 return (-1); 2447 } 2448 return (0); 2449 } 2450 2451 /* 2452 * Given a shared object, traverse its list of needed objects, and load 2453 * each of them. Returns 0 on success. Generates an error message and 2454 * returns -1 on failure. 2455 */ 2456 static int 2457 load_needed_objects(Obj_Entry *first, int flags) 2458 { 2459 Obj_Entry *obj; 2460 2461 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2462 if (obj->marker) 2463 continue; 2464 if (process_needed(obj, obj->needed, flags) == -1) 2465 return (-1); 2466 } 2467 return (0); 2468 } 2469 2470 static int 2471 load_preload_objects(void) 2472 { 2473 char *p = ld_preload; 2474 Obj_Entry *obj; 2475 static const char delim[] = " \t:;"; 2476 2477 if (p == NULL) 2478 return 0; 2479 2480 p += strspn(p, delim); 2481 while (*p != '\0') { 2482 size_t len = strcspn(p, delim); 2483 char savech; 2484 2485 savech = p[len]; 2486 p[len] = '\0'; 2487 obj = load_object(p, -1, NULL, 0); 2488 if (obj == NULL) 2489 return -1; /* XXX - cleanup */ 2490 obj->z_interpose = true; 2491 p[len] = savech; 2492 p += len; 2493 p += strspn(p, delim); 2494 } 2495 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2496 return 0; 2497 } 2498 2499 static const char * 2500 printable_path(const char *path) 2501 { 2502 2503 return (path == NULL ? "<unknown>" : path); 2504 } 2505 2506 /* 2507 * Load a shared object into memory, if it is not already loaded. The 2508 * object may be specified by name or by user-supplied file descriptor 2509 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2510 * duplicate is. 2511 * 2512 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2513 * on failure. 2514 */ 2515 static Obj_Entry * 2516 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2517 { 2518 Obj_Entry *obj; 2519 int fd; 2520 struct stat sb; 2521 char *path; 2522 2523 fd = -1; 2524 if (name != NULL) { 2525 TAILQ_FOREACH(obj, &obj_list, next) { 2526 if (obj->marker || obj->doomed) 2527 continue; 2528 if (object_match_name(obj, name)) 2529 return (obj); 2530 } 2531 2532 path = find_library(name, refobj, &fd); 2533 if (path == NULL) 2534 return (NULL); 2535 } else 2536 path = NULL; 2537 2538 if (fd >= 0) { 2539 /* 2540 * search_library_pathfds() opens a fresh file descriptor for the 2541 * library, so there is no need to dup(). 2542 */ 2543 } else if (fd_u == -1) { 2544 /* 2545 * If we didn't find a match by pathname, or the name is not 2546 * supplied, open the file and check again by device and inode. 2547 * This avoids false mismatches caused by multiple links or ".." 2548 * in pathnames. 2549 * 2550 * To avoid a race, we open the file and use fstat() rather than 2551 * using stat(). 2552 */ 2553 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { 2554 _rtld_error("Cannot open \"%s\"", path); 2555 free(path); 2556 return (NULL); 2557 } 2558 } else { 2559 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2560 if (fd == -1) { 2561 _rtld_error("Cannot dup fd"); 2562 free(path); 2563 return (NULL); 2564 } 2565 } 2566 if (fstat(fd, &sb) == -1) { 2567 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2568 close(fd); 2569 free(path); 2570 return NULL; 2571 } 2572 TAILQ_FOREACH(obj, &obj_list, next) { 2573 if (obj->marker || obj->doomed) 2574 continue; 2575 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2576 break; 2577 } 2578 if (obj != NULL && name != NULL) { 2579 object_add_name(obj, name); 2580 free(path); 2581 close(fd); 2582 return obj; 2583 } 2584 if (flags & RTLD_LO_NOLOAD) { 2585 free(path); 2586 close(fd); 2587 return (NULL); 2588 } 2589 2590 /* First use of this object, so we must map it in */ 2591 obj = do_load_object(fd, name, path, &sb, flags); 2592 if (obj == NULL) 2593 free(path); 2594 close(fd); 2595 2596 return obj; 2597 } 2598 2599 static Obj_Entry * 2600 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2601 int flags) 2602 { 2603 Obj_Entry *obj; 2604 struct statfs fs; 2605 2606 /* 2607 * but first, make sure that environment variables haven't been 2608 * used to circumvent the noexec flag on a filesystem. 2609 */ 2610 if (dangerous_ld_env) { 2611 if (fstatfs(fd, &fs) != 0) { 2612 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2613 return NULL; 2614 } 2615 if (fs.f_flags & MNT_NOEXEC) { 2616 _rtld_error("Cannot execute objects on %s", fs.f_mntonname); 2617 return NULL; 2618 } 2619 } 2620 dbg("loading \"%s\"", printable_path(path)); 2621 obj = map_object(fd, printable_path(path), sbp); 2622 if (obj == NULL) 2623 return NULL; 2624 2625 /* 2626 * If DT_SONAME is present in the object, digest_dynamic2 already 2627 * added it to the object names. 2628 */ 2629 if (name != NULL) 2630 object_add_name(obj, name); 2631 obj->path = path; 2632 if (!digest_dynamic(obj, 0)) 2633 goto errp; 2634 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2635 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2636 if (obj->z_pie && (flags & RTLD_LO_TRACE) == 0) { 2637 dbg("refusing to load PIE executable \"%s\"", obj->path); 2638 _rtld_error("Cannot load PIE binary %s as DSO", obj->path); 2639 goto errp; 2640 } 2641 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2642 RTLD_LO_DLOPEN) { 2643 dbg("refusing to load non-loadable \"%s\"", obj->path); 2644 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2645 goto errp; 2646 } 2647 2648 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2649 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2650 obj_count++; 2651 obj_loads++; 2652 linkmap_add(obj); /* for GDB & dlinfo() */ 2653 max_stack_flags |= obj->stack_flags; 2654 2655 dbg(" %p .. %p: %s", obj->mapbase, 2656 obj->mapbase + obj->mapsize - 1, obj->path); 2657 if (obj->textrel) 2658 dbg(" WARNING: %s has impure text", obj->path); 2659 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2660 obj->path); 2661 2662 return (obj); 2663 2664 errp: 2665 munmap(obj->mapbase, obj->mapsize); 2666 obj_free(obj); 2667 return (NULL); 2668 } 2669 2670 static Obj_Entry * 2671 obj_from_addr(const void *addr) 2672 { 2673 Obj_Entry *obj; 2674 2675 TAILQ_FOREACH(obj, &obj_list, next) { 2676 if (obj->marker) 2677 continue; 2678 if (addr < (void *) obj->mapbase) 2679 continue; 2680 if (addr < (void *)(obj->mapbase + obj->mapsize)) 2681 return obj; 2682 } 2683 return NULL; 2684 } 2685 2686 static void 2687 preinit_main(void) 2688 { 2689 Elf_Addr *preinit_addr; 2690 int index; 2691 2692 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2693 if (preinit_addr == NULL) 2694 return; 2695 2696 for (index = 0; index < obj_main->preinit_array_num; index++) { 2697 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2698 dbg("calling preinit function for %s at %p", obj_main->path, 2699 (void *)preinit_addr[index]); 2700 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2701 0, 0, obj_main->path); 2702 call_init_pointer(obj_main, preinit_addr[index]); 2703 } 2704 } 2705 } 2706 2707 /* 2708 * Call the finalization functions for each of the objects in "list" 2709 * belonging to the DAG of "root" and referenced once. If NULL "root" 2710 * is specified, every finalization function will be called regardless 2711 * of the reference count and the list elements won't be freed. All of 2712 * the objects are expected to have non-NULL fini functions. 2713 */ 2714 static void 2715 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2716 { 2717 Objlist_Entry *elm; 2718 char *saved_msg; 2719 Elf_Addr *fini_addr; 2720 int index; 2721 2722 assert(root == NULL || root->refcount == 1); 2723 2724 if (root != NULL) 2725 root->doomed = true; 2726 2727 /* 2728 * Preserve the current error message since a fini function might 2729 * call into the dynamic linker and overwrite it. 2730 */ 2731 saved_msg = errmsg_save(); 2732 do { 2733 STAILQ_FOREACH(elm, list, link) { 2734 if (root != NULL && (elm->obj->refcount != 1 || 2735 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2736 continue; 2737 /* Remove object from fini list to prevent recursive invocation. */ 2738 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2739 /* Ensure that new references cannot be acquired. */ 2740 elm->obj->doomed = true; 2741 2742 hold_object(elm->obj); 2743 lock_release(rtld_bind_lock, lockstate); 2744 /* 2745 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2746 * When this happens, DT_FINI_ARRAY is processed first. 2747 */ 2748 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2749 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2750 for (index = elm->obj->fini_array_num - 1; index >= 0; 2751 index--) { 2752 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2753 dbg("calling fini function for %s at %p", 2754 elm->obj->path, (void *)fini_addr[index]); 2755 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2756 (void *)fini_addr[index], 0, 0, elm->obj->path); 2757 call_initfini_pointer(elm->obj, fini_addr[index]); 2758 } 2759 } 2760 } 2761 if (elm->obj->fini != (Elf_Addr)NULL) { 2762 dbg("calling fini function for %s at %p", elm->obj->path, 2763 (void *)elm->obj->fini); 2764 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2765 0, 0, elm->obj->path); 2766 call_initfini_pointer(elm->obj, elm->obj->fini); 2767 } 2768 wlock_acquire(rtld_bind_lock, lockstate); 2769 unhold_object(elm->obj); 2770 /* No need to free anything if process is going down. */ 2771 if (root != NULL) 2772 free(elm); 2773 /* 2774 * We must restart the list traversal after every fini call 2775 * because a dlclose() call from the fini function or from 2776 * another thread might have modified the reference counts. 2777 */ 2778 break; 2779 } 2780 } while (elm != NULL); 2781 errmsg_restore(saved_msg); 2782 } 2783 2784 /* 2785 * Call the initialization functions for each of the objects in 2786 * "list". All of the objects are expected to have non-NULL init 2787 * functions. 2788 */ 2789 static void 2790 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2791 { 2792 Objlist_Entry *elm; 2793 Obj_Entry *obj; 2794 char *saved_msg; 2795 Elf_Addr *init_addr; 2796 void (*reg)(void (*)(void)); 2797 int index; 2798 2799 /* 2800 * Clean init_scanned flag so that objects can be rechecked and 2801 * possibly initialized earlier if any of vectors called below 2802 * cause the change by using dlopen. 2803 */ 2804 TAILQ_FOREACH(obj, &obj_list, next) { 2805 if (obj->marker) 2806 continue; 2807 obj->init_scanned = false; 2808 } 2809 2810 /* 2811 * Preserve the current error message since an init function might 2812 * call into the dynamic linker and overwrite it. 2813 */ 2814 saved_msg = errmsg_save(); 2815 STAILQ_FOREACH(elm, list, link) { 2816 if (elm->obj->init_done) /* Initialized early. */ 2817 continue; 2818 /* 2819 * Race: other thread might try to use this object before current 2820 * one completes the initialization. Not much can be done here 2821 * without better locking. 2822 */ 2823 elm->obj->init_done = true; 2824 hold_object(elm->obj); 2825 reg = NULL; 2826 if (elm->obj == obj_main && obj_main->crt_no_init) { 2827 reg = (void (*)(void (*)(void)))get_program_var_addr( 2828 "__libc_atexit", lockstate); 2829 } 2830 lock_release(rtld_bind_lock, lockstate); 2831 if (reg != NULL) { 2832 reg(rtld_exit); 2833 rtld_exit_ptr = rtld_nop_exit; 2834 } 2835 2836 /* 2837 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2838 * When this happens, DT_INIT is processed first. 2839 */ 2840 if (elm->obj->init != (Elf_Addr)NULL) { 2841 dbg("calling init function for %s at %p", elm->obj->path, 2842 (void *)elm->obj->init); 2843 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2844 0, 0, elm->obj->path); 2845 call_init_pointer(elm->obj, elm->obj->init); 2846 } 2847 init_addr = (Elf_Addr *)elm->obj->init_array; 2848 if (init_addr != NULL) { 2849 for (index = 0; index < elm->obj->init_array_num; index++) { 2850 if (init_addr[index] != 0 && init_addr[index] != 1) { 2851 dbg("calling init function for %s at %p", elm->obj->path, 2852 (void *)init_addr[index]); 2853 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2854 (void *)init_addr[index], 0, 0, elm->obj->path); 2855 call_init_pointer(elm->obj, init_addr[index]); 2856 } 2857 } 2858 } 2859 wlock_acquire(rtld_bind_lock, lockstate); 2860 unhold_object(elm->obj); 2861 } 2862 errmsg_restore(saved_msg); 2863 } 2864 2865 static void 2866 objlist_clear(Objlist *list) 2867 { 2868 Objlist_Entry *elm; 2869 2870 while (!STAILQ_EMPTY(list)) { 2871 elm = STAILQ_FIRST(list); 2872 STAILQ_REMOVE_HEAD(list, link); 2873 free(elm); 2874 } 2875 } 2876 2877 static Objlist_Entry * 2878 objlist_find(Objlist *list, const Obj_Entry *obj) 2879 { 2880 Objlist_Entry *elm; 2881 2882 STAILQ_FOREACH(elm, list, link) 2883 if (elm->obj == obj) 2884 return elm; 2885 return NULL; 2886 } 2887 2888 static void 2889 objlist_init(Objlist *list) 2890 { 2891 STAILQ_INIT(list); 2892 } 2893 2894 static void 2895 objlist_push_head(Objlist *list, Obj_Entry *obj) 2896 { 2897 Objlist_Entry *elm; 2898 2899 elm = NEW(Objlist_Entry); 2900 elm->obj = obj; 2901 STAILQ_INSERT_HEAD(list, elm, link); 2902 } 2903 2904 static void 2905 objlist_push_tail(Objlist *list, Obj_Entry *obj) 2906 { 2907 Objlist_Entry *elm; 2908 2909 elm = NEW(Objlist_Entry); 2910 elm->obj = obj; 2911 STAILQ_INSERT_TAIL(list, elm, link); 2912 } 2913 2914 static void 2915 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2916 { 2917 Objlist_Entry *elm, *listelm; 2918 2919 STAILQ_FOREACH(listelm, list, link) { 2920 if (listelm->obj == listobj) 2921 break; 2922 } 2923 elm = NEW(Objlist_Entry); 2924 elm->obj = obj; 2925 if (listelm != NULL) 2926 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2927 else 2928 STAILQ_INSERT_TAIL(list, elm, link); 2929 } 2930 2931 static void 2932 objlist_remove(Objlist *list, Obj_Entry *obj) 2933 { 2934 Objlist_Entry *elm; 2935 2936 if ((elm = objlist_find(list, obj)) != NULL) { 2937 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2938 free(elm); 2939 } 2940 } 2941 2942 /* 2943 * Relocate dag rooted in the specified object. 2944 * Returns 0 on success, or -1 on failure. 2945 */ 2946 2947 static int 2948 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2949 int flags, RtldLockState *lockstate) 2950 { 2951 Objlist_Entry *elm; 2952 int error; 2953 2954 error = 0; 2955 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2956 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2957 lockstate); 2958 if (error == -1) 2959 break; 2960 } 2961 return (error); 2962 } 2963 2964 /* 2965 * Prepare for, or clean after, relocating an object marked with 2966 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 2967 * segments are remapped read-write. After relocations are done, the 2968 * segment's permissions are returned back to the modes specified in 2969 * the phdrs. If any relocation happened, or always for wired 2970 * program, COW is triggered. 2971 */ 2972 static int 2973 reloc_textrel_prot(Obj_Entry *obj, bool before) 2974 { 2975 const Elf_Phdr *ph; 2976 void *base; 2977 size_t l, sz; 2978 int prot; 2979 2980 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 2981 l--, ph++) { 2982 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 2983 continue; 2984 base = obj->relocbase + trunc_page(ph->p_vaddr); 2985 sz = round_page(ph->p_vaddr + ph->p_filesz) - 2986 trunc_page(ph->p_vaddr); 2987 prot = before ? (PROT_READ | PROT_WRITE) : 2988 convert_prot(ph->p_flags); 2989 if (mprotect(base, sz, prot) == -1) { 2990 _rtld_error("%s: Cannot write-%sable text segment: %s", 2991 obj->path, before ? "en" : "dis", 2992 rtld_strerror(errno)); 2993 return (-1); 2994 } 2995 } 2996 return (0); 2997 } 2998 2999 /* 3000 * Relocate single object. 3001 * Returns 0 on success, or -1 on failure. 3002 */ 3003 static int 3004 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 3005 int flags, RtldLockState *lockstate) 3006 { 3007 3008 if (obj->relocated) 3009 return (0); 3010 obj->relocated = true; 3011 if (obj != rtldobj) 3012 dbg("relocating \"%s\"", obj->path); 3013 3014 if (obj->symtab == NULL || obj->strtab == NULL || 3015 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) 3016 dbg("object %s has no run-time symbol table", obj->path); 3017 3018 /* There are relocations to the write-protected text segment. */ 3019 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 3020 return (-1); 3021 3022 /* Process the non-PLT non-IFUNC relocations. */ 3023 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 3024 return (-1); 3025 3026 /* Re-protected the text segment. */ 3027 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 3028 return (-1); 3029 3030 /* Set the special PLT or GOT entries. */ 3031 init_pltgot(obj); 3032 3033 /* Process the PLT relocations. */ 3034 if (reloc_plt(obj, flags, lockstate) == -1) 3035 return (-1); 3036 /* Relocate the jump slots if we are doing immediate binding. */ 3037 if ((obj->bind_now || bind_now) && reloc_jmpslots(obj, flags, 3038 lockstate) == -1) 3039 return (-1); 3040 3041 if (!obj->mainprog && obj_enforce_relro(obj) == -1) 3042 return (-1); 3043 3044 /* 3045 * Set up the magic number and version in the Obj_Entry. These 3046 * were checked in the crt1.o from the original ElfKit, so we 3047 * set them for backward compatibility. 3048 */ 3049 obj->magic = RTLD_MAGIC; 3050 obj->version = RTLD_VERSION; 3051 3052 return (0); 3053 } 3054 3055 /* 3056 * Relocate newly-loaded shared objects. The argument is a pointer to 3057 * the Obj_Entry for the first such object. All objects from the first 3058 * to the end of the list of objects are relocated. Returns 0 on success, 3059 * or -1 on failure. 3060 */ 3061 static int 3062 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 3063 int flags, RtldLockState *lockstate) 3064 { 3065 Obj_Entry *obj; 3066 int error; 3067 3068 for (error = 0, obj = first; obj != NULL; 3069 obj = TAILQ_NEXT(obj, next)) { 3070 if (obj->marker) 3071 continue; 3072 error = relocate_object(obj, bind_now, rtldobj, flags, 3073 lockstate); 3074 if (error == -1) 3075 break; 3076 } 3077 return (error); 3078 } 3079 3080 /* 3081 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 3082 * referencing STT_GNU_IFUNC symbols is postponed till the other 3083 * relocations are done. The indirect functions specified as 3084 * ifunc are allowed to call other symbols, so we need to have 3085 * objects relocated before asking for resolution from indirects. 3086 * 3087 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 3088 * instead of the usual lazy handling of PLT slots. It is 3089 * consistent with how GNU does it. 3090 */ 3091 static int 3092 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 3093 RtldLockState *lockstate) 3094 { 3095 3096 if (obj->ifuncs_resolved) 3097 return (0); 3098 obj->ifuncs_resolved = true; 3099 if (!obj->irelative && !obj->irelative_nonplt && 3100 !((obj->bind_now || bind_now) && obj->gnu_ifunc) && 3101 !obj->non_plt_gnu_ifunc) 3102 return (0); 3103 if (obj_disable_relro(obj) == -1 || 3104 (obj->irelative && reloc_iresolve(obj, lockstate) == -1) || 3105 (obj->irelative_nonplt && reloc_iresolve_nonplt(obj, 3106 lockstate) == -1) || 3107 ((obj->bind_now || bind_now) && obj->gnu_ifunc && 3108 reloc_gnu_ifunc(obj, flags, lockstate) == -1) || 3109 (obj->non_plt_gnu_ifunc && reloc_non_plt(obj, &obj_rtld, 3110 flags | SYMLOOK_IFUNC, lockstate) == -1) || 3111 obj_enforce_relro(obj) == -1) 3112 return (-1); 3113 return (0); 3114 } 3115 3116 static int 3117 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 3118 RtldLockState *lockstate) 3119 { 3120 Objlist_Entry *elm; 3121 Obj_Entry *obj; 3122 3123 STAILQ_FOREACH(elm, list, link) { 3124 obj = elm->obj; 3125 if (obj->marker) 3126 continue; 3127 if (resolve_object_ifunc(obj, bind_now, flags, 3128 lockstate) == -1) 3129 return (-1); 3130 } 3131 return (0); 3132 } 3133 3134 /* 3135 * Cleanup procedure. It will be called (by the atexit mechanism) just 3136 * before the process exits. 3137 */ 3138 static void 3139 rtld_exit(void) 3140 { 3141 RtldLockState lockstate; 3142 3143 wlock_acquire(rtld_bind_lock, &lockstate); 3144 dbg("rtld_exit()"); 3145 objlist_call_fini(&list_fini, NULL, &lockstate); 3146 /* No need to remove the items from the list, since we are exiting. */ 3147 if (!libmap_disable) 3148 lm_fini(); 3149 lock_release(rtld_bind_lock, &lockstate); 3150 } 3151 3152 static void 3153 rtld_nop_exit(void) 3154 { 3155 } 3156 3157 /* 3158 * Iterate over a search path, translate each element, and invoke the 3159 * callback on the result. 3160 */ 3161 static void * 3162 path_enumerate(const char *path, path_enum_proc callback, 3163 const char *refobj_path, void *arg) 3164 { 3165 const char *trans; 3166 if (path == NULL) 3167 return (NULL); 3168 3169 path += strspn(path, ":;"); 3170 while (*path != '\0') { 3171 size_t len; 3172 char *res; 3173 3174 len = strcspn(path, ":;"); 3175 trans = lm_findn(refobj_path, path, len); 3176 if (trans) 3177 res = callback(trans, strlen(trans), arg); 3178 else 3179 res = callback(path, len, arg); 3180 3181 if (res != NULL) 3182 return (res); 3183 3184 path += len; 3185 path += strspn(path, ":;"); 3186 } 3187 3188 return (NULL); 3189 } 3190 3191 struct try_library_args { 3192 const char *name; 3193 size_t namelen; 3194 char *buffer; 3195 size_t buflen; 3196 int fd; 3197 }; 3198 3199 static void * 3200 try_library_path(const char *dir, size_t dirlen, void *param) 3201 { 3202 struct try_library_args *arg; 3203 int fd; 3204 3205 arg = param; 3206 if (*dir == '/' || trust) { 3207 char *pathname; 3208 3209 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 3210 return (NULL); 3211 3212 pathname = arg->buffer; 3213 strncpy(pathname, dir, dirlen); 3214 pathname[dirlen] = '/'; 3215 strcpy(pathname + dirlen + 1, arg->name); 3216 3217 dbg(" Trying \"%s\"", pathname); 3218 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY); 3219 if (fd >= 0) { 3220 dbg(" Opened \"%s\", fd %d", pathname, fd); 3221 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 3222 strcpy(pathname, arg->buffer); 3223 arg->fd = fd; 3224 return (pathname); 3225 } else { 3226 dbg(" Failed to open \"%s\": %s", 3227 pathname, rtld_strerror(errno)); 3228 } 3229 } 3230 return (NULL); 3231 } 3232 3233 static char * 3234 search_library_path(const char *name, const char *path, 3235 const char *refobj_path, int *fdp) 3236 { 3237 char *p; 3238 struct try_library_args arg; 3239 3240 if (path == NULL) 3241 return NULL; 3242 3243 arg.name = name; 3244 arg.namelen = strlen(name); 3245 arg.buffer = xmalloc(PATH_MAX); 3246 arg.buflen = PATH_MAX; 3247 arg.fd = -1; 3248 3249 p = path_enumerate(path, try_library_path, refobj_path, &arg); 3250 *fdp = arg.fd; 3251 3252 free(arg.buffer); 3253 3254 return (p); 3255 } 3256 3257 3258 /* 3259 * Finds the library with the given name using the directory descriptors 3260 * listed in the LD_LIBRARY_PATH_FDS environment variable. 3261 * 3262 * Returns a freshly-opened close-on-exec file descriptor for the library, 3263 * or -1 if the library cannot be found. 3264 */ 3265 static char * 3266 search_library_pathfds(const char *name, const char *path, int *fdp) 3267 { 3268 char *envcopy, *fdstr, *found, *last_token; 3269 size_t len; 3270 int dirfd, fd; 3271 3272 dbg("%s('%s', '%s', fdp)", __func__, name, path); 3273 3274 /* Don't load from user-specified libdirs into setuid binaries. */ 3275 if (!trust) 3276 return (NULL); 3277 3278 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 3279 if (path == NULL) 3280 return (NULL); 3281 3282 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 3283 if (name[0] == '/') { 3284 dbg("Absolute path (%s) passed to %s", name, __func__); 3285 return (NULL); 3286 } 3287 3288 /* 3289 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 3290 * copy of the path, as strtok_r rewrites separator tokens 3291 * with '\0'. 3292 */ 3293 found = NULL; 3294 envcopy = xstrdup(path); 3295 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 3296 fdstr = strtok_r(NULL, ":", &last_token)) { 3297 dirfd = parse_integer(fdstr); 3298 if (dirfd < 0) { 3299 _rtld_error("failed to parse directory FD: '%s'", 3300 fdstr); 3301 break; 3302 } 3303 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 3304 if (fd >= 0) { 3305 *fdp = fd; 3306 len = strlen(fdstr) + strlen(name) + 3; 3307 found = xmalloc(len); 3308 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 3309 _rtld_error("error generating '%d/%s'", 3310 dirfd, name); 3311 rtld_die(); 3312 } 3313 dbg("open('%s') => %d", found, fd); 3314 break; 3315 } 3316 } 3317 free(envcopy); 3318 3319 return (found); 3320 } 3321 3322 3323 int 3324 dlclose(void *handle) 3325 { 3326 RtldLockState lockstate; 3327 int error; 3328 3329 wlock_acquire(rtld_bind_lock, &lockstate); 3330 error = dlclose_locked(handle, &lockstate); 3331 lock_release(rtld_bind_lock, &lockstate); 3332 return (error); 3333 } 3334 3335 static int 3336 dlclose_locked(void *handle, RtldLockState *lockstate) 3337 { 3338 Obj_Entry *root; 3339 3340 root = dlcheck(handle); 3341 if (root == NULL) 3342 return -1; 3343 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 3344 root->path); 3345 3346 /* Unreference the object and its dependencies. */ 3347 root->dl_refcount--; 3348 3349 if (root->refcount == 1) { 3350 /* 3351 * The object will be no longer referenced, so we must unload it. 3352 * First, call the fini functions. 3353 */ 3354 objlist_call_fini(&list_fini, root, lockstate); 3355 3356 unref_dag(root); 3357 3358 /* Finish cleaning up the newly-unreferenced objects. */ 3359 GDB_STATE(RT_DELETE,&root->linkmap); 3360 unload_object(root, lockstate); 3361 GDB_STATE(RT_CONSISTENT,NULL); 3362 } else 3363 unref_dag(root); 3364 3365 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 3366 return 0; 3367 } 3368 3369 char * 3370 dlerror(void) 3371 { 3372 char *msg = error_message; 3373 error_message = NULL; 3374 return msg; 3375 } 3376 3377 /* 3378 * This function is deprecated and has no effect. 3379 */ 3380 void 3381 dllockinit(void *context, 3382 void *(*_lock_create)(void *context) __unused, 3383 void (*_rlock_acquire)(void *lock) __unused, 3384 void (*_wlock_acquire)(void *lock) __unused, 3385 void (*_lock_release)(void *lock) __unused, 3386 void (*_lock_destroy)(void *lock) __unused, 3387 void (*context_destroy)(void *context)) 3388 { 3389 static void *cur_context; 3390 static void (*cur_context_destroy)(void *); 3391 3392 /* Just destroy the context from the previous call, if necessary. */ 3393 if (cur_context_destroy != NULL) 3394 cur_context_destroy(cur_context); 3395 cur_context = context; 3396 cur_context_destroy = context_destroy; 3397 } 3398 3399 void * 3400 dlopen(const char *name, int mode) 3401 { 3402 3403 return (rtld_dlopen(name, -1, mode)); 3404 } 3405 3406 void * 3407 fdlopen(int fd, int mode) 3408 { 3409 3410 return (rtld_dlopen(NULL, fd, mode)); 3411 } 3412 3413 static void * 3414 rtld_dlopen(const char *name, int fd, int mode) 3415 { 3416 RtldLockState lockstate; 3417 int lo_flags; 3418 3419 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3420 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3421 if (ld_tracing != NULL) { 3422 rlock_acquire(rtld_bind_lock, &lockstate); 3423 if (sigsetjmp(lockstate.env, 0) != 0) 3424 lock_upgrade(rtld_bind_lock, &lockstate); 3425 environ = __DECONST(char **, *get_program_var_addr("environ", &lockstate)); 3426 lock_release(rtld_bind_lock, &lockstate); 3427 } 3428 lo_flags = RTLD_LO_DLOPEN; 3429 if (mode & RTLD_NODELETE) 3430 lo_flags |= RTLD_LO_NODELETE; 3431 if (mode & RTLD_NOLOAD) 3432 lo_flags |= RTLD_LO_NOLOAD; 3433 if (mode & RTLD_DEEPBIND) 3434 lo_flags |= RTLD_LO_DEEPBIND; 3435 if (ld_tracing != NULL) 3436 lo_flags |= RTLD_LO_TRACE | RTLD_LO_IGNSTLS; 3437 3438 return (dlopen_object(name, fd, obj_main, lo_flags, 3439 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3440 } 3441 3442 static void 3443 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate) 3444 { 3445 3446 obj->dl_refcount--; 3447 unref_dag(obj); 3448 if (obj->refcount == 0) 3449 unload_object(obj, lockstate); 3450 } 3451 3452 static Obj_Entry * 3453 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3454 int mode, RtldLockState *lockstate) 3455 { 3456 Obj_Entry *old_obj_tail; 3457 Obj_Entry *obj; 3458 Objlist initlist; 3459 RtldLockState mlockstate; 3460 int result; 3461 3462 dbg("dlopen_object name \"%s\" fd %d refobj \"%s\" lo_flags %#x mode %#x", 3463 name != NULL ? name : "<null>", fd, refobj == NULL ? "<null>" : 3464 refobj->path, lo_flags, mode); 3465 objlist_init(&initlist); 3466 3467 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3468 wlock_acquire(rtld_bind_lock, &mlockstate); 3469 lockstate = &mlockstate; 3470 } 3471 GDB_STATE(RT_ADD,NULL); 3472 3473 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 3474 obj = NULL; 3475 if (name == NULL && fd == -1) { 3476 obj = obj_main; 3477 obj->refcount++; 3478 } else { 3479 obj = load_object(name, fd, refobj, lo_flags); 3480 } 3481 3482 if (obj) { 3483 obj->dl_refcount++; 3484 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3485 objlist_push_tail(&list_global, obj); 3486 if (globallist_next(old_obj_tail) != NULL) { 3487 /* We loaded something new. */ 3488 assert(globallist_next(old_obj_tail) == obj); 3489 if ((lo_flags & RTLD_LO_DEEPBIND) != 0) 3490 obj->symbolic = true; 3491 result = 0; 3492 if ((lo_flags & (RTLD_LO_EARLY | RTLD_LO_IGNSTLS)) == 0 && 3493 obj->static_tls && !allocate_tls_offset(obj)) { 3494 _rtld_error("%s: No space available " 3495 "for static Thread Local Storage", obj->path); 3496 result = -1; 3497 } 3498 if (result != -1) 3499 result = load_needed_objects(obj, lo_flags & (RTLD_LO_DLOPEN | 3500 RTLD_LO_EARLY | RTLD_LO_IGNSTLS | RTLD_LO_TRACE)); 3501 init_dag(obj); 3502 ref_dag(obj); 3503 if (result != -1) 3504 result = rtld_verify_versions(&obj->dagmembers); 3505 if (result != -1 && ld_tracing) 3506 goto trace; 3507 if (result == -1 || relocate_object_dag(obj, 3508 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3509 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3510 lockstate) == -1) { 3511 dlopen_cleanup(obj, lockstate); 3512 obj = NULL; 3513 } else if (lo_flags & RTLD_LO_EARLY) { 3514 /* 3515 * Do not call the init functions for early loaded 3516 * filtees. The image is still not initialized enough 3517 * for them to work. 3518 * 3519 * Our object is found by the global object list and 3520 * will be ordered among all init calls done right 3521 * before transferring control to main. 3522 */ 3523 } else { 3524 /* Make list of init functions to call. */ 3525 initlist_add_objects(obj, obj, &initlist); 3526 } 3527 /* 3528 * Process all no_delete or global objects here, given 3529 * them own DAGs to prevent their dependencies from being 3530 * unloaded. This has to be done after we have loaded all 3531 * of the dependencies, so that we do not miss any. 3532 */ 3533 if (obj != NULL) 3534 process_z(obj); 3535 } else { 3536 /* 3537 * Bump the reference counts for objects on this DAG. If 3538 * this is the first dlopen() call for the object that was 3539 * already loaded as a dependency, initialize the dag 3540 * starting at it. 3541 */ 3542 init_dag(obj); 3543 ref_dag(obj); 3544 3545 if ((lo_flags & RTLD_LO_TRACE) != 0) 3546 goto trace; 3547 } 3548 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3549 obj->z_nodelete) && !obj->ref_nodel) { 3550 dbg("obj %s nodelete", obj->path); 3551 ref_dag(obj); 3552 obj->z_nodelete = obj->ref_nodel = true; 3553 } 3554 } 3555 3556 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3557 name); 3558 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3559 3560 if ((lo_flags & RTLD_LO_EARLY) == 0) { 3561 map_stacks_exec(lockstate); 3562 if (obj != NULL) 3563 distribute_static_tls(&initlist, lockstate); 3564 } 3565 3566 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3567 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3568 lockstate) == -1) { 3569 objlist_clear(&initlist); 3570 dlopen_cleanup(obj, lockstate); 3571 if (lockstate == &mlockstate) 3572 lock_release(rtld_bind_lock, lockstate); 3573 return (NULL); 3574 } 3575 3576 if (!(lo_flags & RTLD_LO_EARLY)) { 3577 /* Call the init functions. */ 3578 objlist_call_init(&initlist, lockstate); 3579 } 3580 objlist_clear(&initlist); 3581 if (lockstate == &mlockstate) 3582 lock_release(rtld_bind_lock, lockstate); 3583 return obj; 3584 trace: 3585 trace_loaded_objects(obj); 3586 if (lockstate == &mlockstate) 3587 lock_release(rtld_bind_lock, lockstate); 3588 exit(0); 3589 } 3590 3591 static void * 3592 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3593 int flags) 3594 { 3595 DoneList donelist; 3596 const Obj_Entry *obj, *defobj; 3597 const Elf_Sym *def; 3598 SymLook req; 3599 RtldLockState lockstate; 3600 tls_index ti; 3601 void *sym; 3602 int res; 3603 3604 def = NULL; 3605 defobj = NULL; 3606 symlook_init(&req, name); 3607 req.ventry = ve; 3608 req.flags = flags | SYMLOOK_IN_PLT; 3609 req.lockstate = &lockstate; 3610 3611 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3612 rlock_acquire(rtld_bind_lock, &lockstate); 3613 if (sigsetjmp(lockstate.env, 0) != 0) 3614 lock_upgrade(rtld_bind_lock, &lockstate); 3615 if (handle == NULL || handle == RTLD_NEXT || 3616 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3617 3618 if ((obj = obj_from_addr(retaddr)) == NULL) { 3619 _rtld_error("Cannot determine caller's shared object"); 3620 lock_release(rtld_bind_lock, &lockstate); 3621 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3622 return NULL; 3623 } 3624 if (handle == NULL) { /* Just the caller's shared object. */ 3625 res = symlook_obj(&req, obj); 3626 if (res == 0) { 3627 def = req.sym_out; 3628 defobj = req.defobj_out; 3629 } 3630 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3631 handle == RTLD_SELF) { /* ... caller included */ 3632 if (handle == RTLD_NEXT) 3633 obj = globallist_next(obj); 3634 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3635 if (obj->marker) 3636 continue; 3637 res = symlook_obj(&req, obj); 3638 if (res == 0) { 3639 if (def == NULL || 3640 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3641 def = req.sym_out; 3642 defobj = req.defobj_out; 3643 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3644 break; 3645 } 3646 } 3647 } 3648 /* 3649 * Search the dynamic linker itself, and possibly resolve the 3650 * symbol from there. This is how the application links to 3651 * dynamic linker services such as dlopen. 3652 */ 3653 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3654 res = symlook_obj(&req, &obj_rtld); 3655 if (res == 0) { 3656 def = req.sym_out; 3657 defobj = req.defobj_out; 3658 } 3659 } 3660 } else { 3661 assert(handle == RTLD_DEFAULT); 3662 res = symlook_default(&req, obj); 3663 if (res == 0) { 3664 defobj = req.defobj_out; 3665 def = req.sym_out; 3666 } 3667 } 3668 } else { 3669 if ((obj = dlcheck(handle)) == NULL) { 3670 lock_release(rtld_bind_lock, &lockstate); 3671 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3672 return NULL; 3673 } 3674 3675 donelist_init(&donelist); 3676 if (obj->mainprog) { 3677 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3678 res = symlook_global(&req, &donelist); 3679 if (res == 0) { 3680 def = req.sym_out; 3681 defobj = req.defobj_out; 3682 } 3683 /* 3684 * Search the dynamic linker itself, and possibly resolve the 3685 * symbol from there. This is how the application links to 3686 * dynamic linker services such as dlopen. 3687 */ 3688 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3689 res = symlook_obj(&req, &obj_rtld); 3690 if (res == 0) { 3691 def = req.sym_out; 3692 defobj = req.defobj_out; 3693 } 3694 } 3695 } 3696 else { 3697 /* Search the whole DAG rooted at the given object. */ 3698 res = symlook_list(&req, &obj->dagmembers, &donelist); 3699 if (res == 0) { 3700 def = req.sym_out; 3701 defobj = req.defobj_out; 3702 } 3703 } 3704 } 3705 3706 if (def != NULL) { 3707 lock_release(rtld_bind_lock, &lockstate); 3708 3709 /* 3710 * The value required by the caller is derived from the value 3711 * of the symbol. this is simply the relocated value of the 3712 * symbol. 3713 */ 3714 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3715 sym = make_function_pointer(def, defobj); 3716 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3717 sym = rtld_resolve_ifunc(defobj, def); 3718 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3719 ti.ti_module = defobj->tlsindex; 3720 ti.ti_offset = def->st_value; 3721 sym = __tls_get_addr(&ti); 3722 } else 3723 sym = defobj->relocbase + def->st_value; 3724 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3725 return (sym); 3726 } 3727 3728 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "", 3729 ve != NULL ? ve->name : ""); 3730 lock_release(rtld_bind_lock, &lockstate); 3731 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3732 return NULL; 3733 } 3734 3735 void * 3736 dlsym(void *handle, const char *name) 3737 { 3738 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3739 SYMLOOK_DLSYM); 3740 } 3741 3742 dlfunc_t 3743 dlfunc(void *handle, const char *name) 3744 { 3745 union { 3746 void *d; 3747 dlfunc_t f; 3748 } rv; 3749 3750 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3751 SYMLOOK_DLSYM); 3752 return (rv.f); 3753 } 3754 3755 void * 3756 dlvsym(void *handle, const char *name, const char *version) 3757 { 3758 Ver_Entry ventry; 3759 3760 ventry.name = version; 3761 ventry.file = NULL; 3762 ventry.hash = elf_hash(version); 3763 ventry.flags= 0; 3764 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3765 SYMLOOK_DLSYM); 3766 } 3767 3768 int 3769 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3770 { 3771 const Obj_Entry *obj; 3772 RtldLockState lockstate; 3773 3774 rlock_acquire(rtld_bind_lock, &lockstate); 3775 obj = obj_from_addr(addr); 3776 if (obj == NULL) { 3777 _rtld_error("No shared object contains address"); 3778 lock_release(rtld_bind_lock, &lockstate); 3779 return (0); 3780 } 3781 rtld_fill_dl_phdr_info(obj, phdr_info); 3782 lock_release(rtld_bind_lock, &lockstate); 3783 return (1); 3784 } 3785 3786 int 3787 dladdr(const void *addr, Dl_info *info) 3788 { 3789 const Obj_Entry *obj; 3790 const Elf_Sym *def; 3791 void *symbol_addr; 3792 unsigned long symoffset; 3793 RtldLockState lockstate; 3794 3795 rlock_acquire(rtld_bind_lock, &lockstate); 3796 obj = obj_from_addr(addr); 3797 if (obj == NULL) { 3798 _rtld_error("No shared object contains address"); 3799 lock_release(rtld_bind_lock, &lockstate); 3800 return 0; 3801 } 3802 info->dli_fname = obj->path; 3803 info->dli_fbase = obj->mapbase; 3804 info->dli_saddr = (void *)0; 3805 info->dli_sname = NULL; 3806 3807 /* 3808 * Walk the symbol list looking for the symbol whose address is 3809 * closest to the address sent in. 3810 */ 3811 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3812 def = obj->symtab + symoffset; 3813 3814 /* 3815 * For skip the symbol if st_shndx is either SHN_UNDEF or 3816 * SHN_COMMON. 3817 */ 3818 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3819 continue; 3820 3821 /* 3822 * If the symbol is greater than the specified address, or if it 3823 * is further away from addr than the current nearest symbol, 3824 * then reject it. 3825 */ 3826 symbol_addr = obj->relocbase + def->st_value; 3827 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3828 continue; 3829 3830 /* Update our idea of the nearest symbol. */ 3831 info->dli_sname = obj->strtab + def->st_name; 3832 info->dli_saddr = symbol_addr; 3833 3834 /* Exact match? */ 3835 if (info->dli_saddr == addr) 3836 break; 3837 } 3838 lock_release(rtld_bind_lock, &lockstate); 3839 return 1; 3840 } 3841 3842 int 3843 dlinfo(void *handle, int request, void *p) 3844 { 3845 const Obj_Entry *obj; 3846 RtldLockState lockstate; 3847 int error; 3848 3849 rlock_acquire(rtld_bind_lock, &lockstate); 3850 3851 if (handle == NULL || handle == RTLD_SELF) { 3852 void *retaddr; 3853 3854 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3855 if ((obj = obj_from_addr(retaddr)) == NULL) 3856 _rtld_error("Cannot determine caller's shared object"); 3857 } else 3858 obj = dlcheck(handle); 3859 3860 if (obj == NULL) { 3861 lock_release(rtld_bind_lock, &lockstate); 3862 return (-1); 3863 } 3864 3865 error = 0; 3866 switch (request) { 3867 case RTLD_DI_LINKMAP: 3868 *((struct link_map const **)p) = &obj->linkmap; 3869 break; 3870 case RTLD_DI_ORIGIN: 3871 error = rtld_dirname(obj->path, p); 3872 break; 3873 3874 case RTLD_DI_SERINFOSIZE: 3875 case RTLD_DI_SERINFO: 3876 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3877 break; 3878 3879 default: 3880 _rtld_error("Invalid request %d passed to dlinfo()", request); 3881 error = -1; 3882 } 3883 3884 lock_release(rtld_bind_lock, &lockstate); 3885 3886 return (error); 3887 } 3888 3889 static void 3890 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3891 { 3892 3893 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3894 phdr_info->dlpi_name = obj->path; 3895 phdr_info->dlpi_phdr = obj->phdr; 3896 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3897 phdr_info->dlpi_tls_modid = obj->tlsindex; 3898 phdr_info->dlpi_tls_data = obj->tlsinit; 3899 phdr_info->dlpi_adds = obj_loads; 3900 phdr_info->dlpi_subs = obj_loads - obj_count; 3901 } 3902 3903 int 3904 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3905 { 3906 struct dl_phdr_info phdr_info; 3907 Obj_Entry *obj, marker; 3908 RtldLockState bind_lockstate, phdr_lockstate; 3909 int error; 3910 3911 init_marker(&marker); 3912 error = 0; 3913 3914 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3915 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3916 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 3917 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 3918 rtld_fill_dl_phdr_info(obj, &phdr_info); 3919 hold_object(obj); 3920 lock_release(rtld_bind_lock, &bind_lockstate); 3921 3922 error = callback(&phdr_info, sizeof phdr_info, param); 3923 3924 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3925 unhold_object(obj); 3926 obj = globallist_next(&marker); 3927 TAILQ_REMOVE(&obj_list, &marker, next); 3928 if (error != 0) { 3929 lock_release(rtld_bind_lock, &bind_lockstate); 3930 lock_release(rtld_phdr_lock, &phdr_lockstate); 3931 return (error); 3932 } 3933 } 3934 3935 if (error == 0) { 3936 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3937 lock_release(rtld_bind_lock, &bind_lockstate); 3938 error = callback(&phdr_info, sizeof(phdr_info), param); 3939 } 3940 lock_release(rtld_phdr_lock, &phdr_lockstate); 3941 return (error); 3942 } 3943 3944 static void * 3945 fill_search_info(const char *dir, size_t dirlen, void *param) 3946 { 3947 struct fill_search_info_args *arg; 3948 3949 arg = param; 3950 3951 if (arg->request == RTLD_DI_SERINFOSIZE) { 3952 arg->serinfo->dls_cnt ++; 3953 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3954 } else { 3955 struct dl_serpath *s_entry; 3956 3957 s_entry = arg->serpath; 3958 s_entry->dls_name = arg->strspace; 3959 s_entry->dls_flags = arg->flags; 3960 3961 strncpy(arg->strspace, dir, dirlen); 3962 arg->strspace[dirlen] = '\0'; 3963 3964 arg->strspace += dirlen + 1; 3965 arg->serpath++; 3966 } 3967 3968 return (NULL); 3969 } 3970 3971 static int 3972 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3973 { 3974 struct dl_serinfo _info; 3975 struct fill_search_info_args args; 3976 3977 args.request = RTLD_DI_SERINFOSIZE; 3978 args.serinfo = &_info; 3979 3980 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3981 _info.dls_cnt = 0; 3982 3983 path_enumerate(obj->rpath, fill_search_info, NULL, &args); 3984 path_enumerate(ld_library_path, fill_search_info, NULL, &args); 3985 path_enumerate(obj->runpath, fill_search_info, NULL, &args); 3986 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args); 3987 if (!obj->z_nodeflib) 3988 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args); 3989 3990 3991 if (request == RTLD_DI_SERINFOSIZE) { 3992 info->dls_size = _info.dls_size; 3993 info->dls_cnt = _info.dls_cnt; 3994 return (0); 3995 } 3996 3997 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3998 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3999 return (-1); 4000 } 4001 4002 args.request = RTLD_DI_SERINFO; 4003 args.serinfo = info; 4004 args.serpath = &info->dls_serpath[0]; 4005 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 4006 4007 args.flags = LA_SER_RUNPATH; 4008 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL) 4009 return (-1); 4010 4011 args.flags = LA_SER_LIBPATH; 4012 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL) 4013 return (-1); 4014 4015 args.flags = LA_SER_RUNPATH; 4016 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL) 4017 return (-1); 4018 4019 args.flags = LA_SER_CONFIG; 4020 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args) 4021 != NULL) 4022 return (-1); 4023 4024 args.flags = LA_SER_DEFAULT; 4025 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path, 4026 fill_search_info, NULL, &args) != NULL) 4027 return (-1); 4028 return (0); 4029 } 4030 4031 static int 4032 rtld_dirname(const char *path, char *bname) 4033 { 4034 const char *endp; 4035 4036 /* Empty or NULL string gets treated as "." */ 4037 if (path == NULL || *path == '\0') { 4038 bname[0] = '.'; 4039 bname[1] = '\0'; 4040 return (0); 4041 } 4042 4043 /* Strip trailing slashes */ 4044 endp = path + strlen(path) - 1; 4045 while (endp > path && *endp == '/') 4046 endp--; 4047 4048 /* Find the start of the dir */ 4049 while (endp > path && *endp != '/') 4050 endp--; 4051 4052 /* Either the dir is "/" or there are no slashes */ 4053 if (endp == path) { 4054 bname[0] = *endp == '/' ? '/' : '.'; 4055 bname[1] = '\0'; 4056 return (0); 4057 } else { 4058 do { 4059 endp--; 4060 } while (endp > path && *endp == '/'); 4061 } 4062 4063 if (endp - path + 2 > PATH_MAX) 4064 { 4065 _rtld_error("Filename is too long: %s", path); 4066 return(-1); 4067 } 4068 4069 strncpy(bname, path, endp - path + 1); 4070 bname[endp - path + 1] = '\0'; 4071 return (0); 4072 } 4073 4074 static int 4075 rtld_dirname_abs(const char *path, char *base) 4076 { 4077 char *last; 4078 4079 if (realpath(path, base) == NULL) { 4080 _rtld_error("realpath \"%s\" failed (%s)", path, 4081 rtld_strerror(errno)); 4082 return (-1); 4083 } 4084 dbg("%s -> %s", path, base); 4085 last = strrchr(base, '/'); 4086 if (last == NULL) { 4087 _rtld_error("non-abs result from realpath \"%s\"", path); 4088 return (-1); 4089 } 4090 if (last != base) 4091 *last = '\0'; 4092 return (0); 4093 } 4094 4095 static void 4096 linkmap_add(Obj_Entry *obj) 4097 { 4098 struct link_map *l, *prev; 4099 4100 l = &obj->linkmap; 4101 l->l_name = obj->path; 4102 l->l_base = obj->mapbase; 4103 l->l_ld = obj->dynamic; 4104 l->l_addr = obj->relocbase; 4105 4106 if (r_debug.r_map == NULL) { 4107 r_debug.r_map = l; 4108 return; 4109 } 4110 4111 /* 4112 * Scan to the end of the list, but not past the entry for the 4113 * dynamic linker, which we want to keep at the very end. 4114 */ 4115 for (prev = r_debug.r_map; 4116 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 4117 prev = prev->l_next) 4118 ; 4119 4120 /* Link in the new entry. */ 4121 l->l_prev = prev; 4122 l->l_next = prev->l_next; 4123 if (l->l_next != NULL) 4124 l->l_next->l_prev = l; 4125 prev->l_next = l; 4126 } 4127 4128 static void 4129 linkmap_delete(Obj_Entry *obj) 4130 { 4131 struct link_map *l; 4132 4133 l = &obj->linkmap; 4134 if (l->l_prev == NULL) { 4135 if ((r_debug.r_map = l->l_next) != NULL) 4136 l->l_next->l_prev = NULL; 4137 return; 4138 } 4139 4140 if ((l->l_prev->l_next = l->l_next) != NULL) 4141 l->l_next->l_prev = l->l_prev; 4142 } 4143 4144 /* 4145 * Function for the debugger to set a breakpoint on to gain control. 4146 * 4147 * The two parameters allow the debugger to easily find and determine 4148 * what the runtime loader is doing and to whom it is doing it. 4149 * 4150 * When the loadhook trap is hit (r_debug_state, set at program 4151 * initialization), the arguments can be found on the stack: 4152 * 4153 * +8 struct link_map *m 4154 * +4 struct r_debug *rd 4155 * +0 RetAddr 4156 */ 4157 void 4158 r_debug_state(struct r_debug* rd __unused, struct link_map *m __unused) 4159 { 4160 /* 4161 * The following is a hack to force the compiler to emit calls to 4162 * this function, even when optimizing. If the function is empty, 4163 * the compiler is not obliged to emit any code for calls to it, 4164 * even when marked __noinline. However, gdb depends on those 4165 * calls being made. 4166 */ 4167 __compiler_membar(); 4168 } 4169 4170 /* 4171 * A function called after init routines have completed. This can be used to 4172 * break before a program's entry routine is called, and can be used when 4173 * main is not available in the symbol table. 4174 */ 4175 void 4176 _r_debug_postinit(struct link_map *m __unused) 4177 { 4178 4179 /* See r_debug_state(). */ 4180 __compiler_membar(); 4181 } 4182 4183 static void 4184 release_object(Obj_Entry *obj) 4185 { 4186 4187 if (obj->holdcount > 0) { 4188 obj->unholdfree = true; 4189 return; 4190 } 4191 munmap(obj->mapbase, obj->mapsize); 4192 linkmap_delete(obj); 4193 obj_free(obj); 4194 } 4195 4196 /* 4197 * Get address of the pointer variable in the main program. 4198 * Prefer non-weak symbol over the weak one. 4199 */ 4200 static const void ** 4201 get_program_var_addr(const char *name, RtldLockState *lockstate) 4202 { 4203 SymLook req; 4204 DoneList donelist; 4205 4206 symlook_init(&req, name); 4207 req.lockstate = lockstate; 4208 donelist_init(&donelist); 4209 if (symlook_global(&req, &donelist) != 0) 4210 return (NULL); 4211 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 4212 return ((const void **)make_function_pointer(req.sym_out, 4213 req.defobj_out)); 4214 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 4215 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 4216 else 4217 return ((const void **)(req.defobj_out->relocbase + 4218 req.sym_out->st_value)); 4219 } 4220 4221 /* 4222 * Set a pointer variable in the main program to the given value. This 4223 * is used to set key variables such as "environ" before any of the 4224 * init functions are called. 4225 */ 4226 static void 4227 set_program_var(const char *name, const void *value) 4228 { 4229 const void **addr; 4230 4231 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 4232 dbg("\"%s\": *%p <-- %p", name, addr, value); 4233 *addr = value; 4234 } 4235 } 4236 4237 /* 4238 * Search the global objects, including dependencies and main object, 4239 * for the given symbol. 4240 */ 4241 static int 4242 symlook_global(SymLook *req, DoneList *donelist) 4243 { 4244 SymLook req1; 4245 const Objlist_Entry *elm; 4246 int res; 4247 4248 symlook_init_from_req(&req1, req); 4249 4250 /* Search all objects loaded at program start up. */ 4251 if (req->defobj_out == NULL || 4252 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4253 res = symlook_list(&req1, &list_main, donelist); 4254 if (res == 0 && (req->defobj_out == NULL || 4255 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4256 req->sym_out = req1.sym_out; 4257 req->defobj_out = req1.defobj_out; 4258 assert(req->defobj_out != NULL); 4259 } 4260 } 4261 4262 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 4263 STAILQ_FOREACH(elm, &list_global, link) { 4264 if (req->defobj_out != NULL && 4265 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4266 break; 4267 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 4268 if (res == 0 && (req->defobj_out == NULL || 4269 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4270 req->sym_out = req1.sym_out; 4271 req->defobj_out = req1.defobj_out; 4272 assert(req->defobj_out != NULL); 4273 } 4274 } 4275 4276 return (req->sym_out != NULL ? 0 : ESRCH); 4277 } 4278 4279 /* 4280 * Given a symbol name in a referencing object, find the corresponding 4281 * definition of the symbol. Returns a pointer to the symbol, or NULL if 4282 * no definition was found. Returns a pointer to the Obj_Entry of the 4283 * defining object via the reference parameter DEFOBJ_OUT. 4284 */ 4285 static int 4286 symlook_default(SymLook *req, const Obj_Entry *refobj) 4287 { 4288 DoneList donelist; 4289 const Objlist_Entry *elm; 4290 SymLook req1; 4291 int res; 4292 4293 donelist_init(&donelist); 4294 symlook_init_from_req(&req1, req); 4295 4296 /* 4297 * Look first in the referencing object if linked symbolically, 4298 * and similarly handle protected symbols. 4299 */ 4300 res = symlook_obj(&req1, refobj); 4301 if (res == 0 && (refobj->symbolic || 4302 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) { 4303 req->sym_out = req1.sym_out; 4304 req->defobj_out = req1.defobj_out; 4305 assert(req->defobj_out != NULL); 4306 } 4307 if (refobj->symbolic || req->defobj_out != NULL) 4308 donelist_check(&donelist, refobj); 4309 4310 symlook_global(req, &donelist); 4311 4312 /* Search all dlopened DAGs containing the referencing object. */ 4313 STAILQ_FOREACH(elm, &refobj->dldags, link) { 4314 if (req->sym_out != NULL && 4315 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4316 break; 4317 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 4318 if (res == 0 && (req->sym_out == NULL || 4319 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4320 req->sym_out = req1.sym_out; 4321 req->defobj_out = req1.defobj_out; 4322 assert(req->defobj_out != NULL); 4323 } 4324 } 4325 4326 /* 4327 * Search the dynamic linker itself, and possibly resolve the 4328 * symbol from there. This is how the application links to 4329 * dynamic linker services such as dlopen. 4330 */ 4331 if (req->sym_out == NULL || 4332 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4333 res = symlook_obj(&req1, &obj_rtld); 4334 if (res == 0) { 4335 req->sym_out = req1.sym_out; 4336 req->defobj_out = req1.defobj_out; 4337 assert(req->defobj_out != NULL); 4338 } 4339 } 4340 4341 return (req->sym_out != NULL ? 0 : ESRCH); 4342 } 4343 4344 static int 4345 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 4346 { 4347 const Elf_Sym *def; 4348 const Obj_Entry *defobj; 4349 const Objlist_Entry *elm; 4350 SymLook req1; 4351 int res; 4352 4353 def = NULL; 4354 defobj = NULL; 4355 STAILQ_FOREACH(elm, objlist, link) { 4356 if (donelist_check(dlp, elm->obj)) 4357 continue; 4358 symlook_init_from_req(&req1, req); 4359 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 4360 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4361 def = req1.sym_out; 4362 defobj = req1.defobj_out; 4363 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4364 break; 4365 } 4366 } 4367 } 4368 if (def != NULL) { 4369 req->sym_out = def; 4370 req->defobj_out = defobj; 4371 return (0); 4372 } 4373 return (ESRCH); 4374 } 4375 4376 /* 4377 * Search the chain of DAGS cointed to by the given Needed_Entry 4378 * for a symbol of the given name. Each DAG is scanned completely 4379 * before advancing to the next one. Returns a pointer to the symbol, 4380 * or NULL if no definition was found. 4381 */ 4382 static int 4383 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 4384 { 4385 const Elf_Sym *def; 4386 const Needed_Entry *n; 4387 const Obj_Entry *defobj; 4388 SymLook req1; 4389 int res; 4390 4391 def = NULL; 4392 defobj = NULL; 4393 symlook_init_from_req(&req1, req); 4394 for (n = needed; n != NULL; n = n->next) { 4395 if (n->obj == NULL || 4396 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 4397 continue; 4398 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4399 def = req1.sym_out; 4400 defobj = req1.defobj_out; 4401 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4402 break; 4403 } 4404 } 4405 if (def != NULL) { 4406 req->sym_out = def; 4407 req->defobj_out = defobj; 4408 return (0); 4409 } 4410 return (ESRCH); 4411 } 4412 4413 /* 4414 * Search the symbol table of a single shared object for a symbol of 4415 * the given name and version, if requested. Returns a pointer to the 4416 * symbol, or NULL if no definition was found. If the object is 4417 * filter, return filtered symbol from filtee. 4418 * 4419 * The symbol's hash value is passed in for efficiency reasons; that 4420 * eliminates many recomputations of the hash value. 4421 */ 4422 int 4423 symlook_obj(SymLook *req, const Obj_Entry *obj) 4424 { 4425 DoneList donelist; 4426 SymLook req1; 4427 int flags, res, mres; 4428 4429 /* 4430 * If there is at least one valid hash at this point, we prefer to 4431 * use the faster GNU version if available. 4432 */ 4433 if (obj->valid_hash_gnu) 4434 mres = symlook_obj1_gnu(req, obj); 4435 else if (obj->valid_hash_sysv) 4436 mres = symlook_obj1_sysv(req, obj); 4437 else 4438 return (EINVAL); 4439 4440 if (mres == 0) { 4441 if (obj->needed_filtees != NULL) { 4442 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4443 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4444 donelist_init(&donelist); 4445 symlook_init_from_req(&req1, req); 4446 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 4447 if (res == 0) { 4448 req->sym_out = req1.sym_out; 4449 req->defobj_out = req1.defobj_out; 4450 } 4451 return (res); 4452 } 4453 if (obj->needed_aux_filtees != NULL) { 4454 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4455 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4456 donelist_init(&donelist); 4457 symlook_init_from_req(&req1, req); 4458 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 4459 if (res == 0) { 4460 req->sym_out = req1.sym_out; 4461 req->defobj_out = req1.defobj_out; 4462 return (res); 4463 } 4464 } 4465 } 4466 return (mres); 4467 } 4468 4469 /* Symbol match routine common to both hash functions */ 4470 static bool 4471 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4472 const unsigned long symnum) 4473 { 4474 Elf_Versym verndx; 4475 const Elf_Sym *symp; 4476 const char *strp; 4477 4478 symp = obj->symtab + symnum; 4479 strp = obj->strtab + symp->st_name; 4480 4481 switch (ELF_ST_TYPE(symp->st_info)) { 4482 case STT_FUNC: 4483 case STT_NOTYPE: 4484 case STT_OBJECT: 4485 case STT_COMMON: 4486 case STT_GNU_IFUNC: 4487 if (symp->st_value == 0) 4488 return (false); 4489 /* fallthrough */ 4490 case STT_TLS: 4491 if (symp->st_shndx != SHN_UNDEF) 4492 break; 4493 #ifndef __mips__ 4494 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4495 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4496 break; 4497 #endif 4498 /* fallthrough */ 4499 default: 4500 return (false); 4501 } 4502 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4503 return (false); 4504 4505 if (req->ventry == NULL) { 4506 if (obj->versyms != NULL) { 4507 verndx = VER_NDX(obj->versyms[symnum]); 4508 if (verndx > obj->vernum) { 4509 _rtld_error( 4510 "%s: symbol %s references wrong version %d", 4511 obj->path, obj->strtab + symnum, verndx); 4512 return (false); 4513 } 4514 /* 4515 * If we are not called from dlsym (i.e. this 4516 * is a normal relocation from unversioned 4517 * binary), accept the symbol immediately if 4518 * it happens to have first version after this 4519 * shared object became versioned. Otherwise, 4520 * if symbol is versioned and not hidden, 4521 * remember it. If it is the only symbol with 4522 * this name exported by the shared object, it 4523 * will be returned as a match by the calling 4524 * function. If symbol is global (verndx < 2) 4525 * accept it unconditionally. 4526 */ 4527 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4528 verndx == VER_NDX_GIVEN) { 4529 result->sym_out = symp; 4530 return (true); 4531 } 4532 else if (verndx >= VER_NDX_GIVEN) { 4533 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4534 == 0) { 4535 if (result->vsymp == NULL) 4536 result->vsymp = symp; 4537 result->vcount++; 4538 } 4539 return (false); 4540 } 4541 } 4542 result->sym_out = symp; 4543 return (true); 4544 } 4545 if (obj->versyms == NULL) { 4546 if (object_match_name(obj, req->ventry->name)) { 4547 _rtld_error("%s: object %s should provide version %s " 4548 "for symbol %s", obj_rtld.path, obj->path, 4549 req->ventry->name, obj->strtab + symnum); 4550 return (false); 4551 } 4552 } else { 4553 verndx = VER_NDX(obj->versyms[symnum]); 4554 if (verndx > obj->vernum) { 4555 _rtld_error("%s: symbol %s references wrong version %d", 4556 obj->path, obj->strtab + symnum, verndx); 4557 return (false); 4558 } 4559 if (obj->vertab[verndx].hash != req->ventry->hash || 4560 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4561 /* 4562 * Version does not match. Look if this is a 4563 * global symbol and if it is not hidden. If 4564 * global symbol (verndx < 2) is available, 4565 * use it. Do not return symbol if we are 4566 * called by dlvsym, because dlvsym looks for 4567 * a specific version and default one is not 4568 * what dlvsym wants. 4569 */ 4570 if ((req->flags & SYMLOOK_DLSYM) || 4571 (verndx >= VER_NDX_GIVEN) || 4572 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4573 return (false); 4574 } 4575 } 4576 result->sym_out = symp; 4577 return (true); 4578 } 4579 4580 /* 4581 * Search for symbol using SysV hash function. 4582 * obj->buckets is known not to be NULL at this point; the test for this was 4583 * performed with the obj->valid_hash_sysv assignment. 4584 */ 4585 static int 4586 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4587 { 4588 unsigned long symnum; 4589 Sym_Match_Result matchres; 4590 4591 matchres.sym_out = NULL; 4592 matchres.vsymp = NULL; 4593 matchres.vcount = 0; 4594 4595 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4596 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4597 if (symnum >= obj->nchains) 4598 return (ESRCH); /* Bad object */ 4599 4600 if (matched_symbol(req, obj, &matchres, symnum)) { 4601 req->sym_out = matchres.sym_out; 4602 req->defobj_out = obj; 4603 return (0); 4604 } 4605 } 4606 if (matchres.vcount == 1) { 4607 req->sym_out = matchres.vsymp; 4608 req->defobj_out = obj; 4609 return (0); 4610 } 4611 return (ESRCH); 4612 } 4613 4614 /* Search for symbol using GNU hash function */ 4615 static int 4616 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4617 { 4618 Elf_Addr bloom_word; 4619 const Elf32_Word *hashval; 4620 Elf32_Word bucket; 4621 Sym_Match_Result matchres; 4622 unsigned int h1, h2; 4623 unsigned long symnum; 4624 4625 matchres.sym_out = NULL; 4626 matchres.vsymp = NULL; 4627 matchres.vcount = 0; 4628 4629 /* Pick right bitmask word from Bloom filter array */ 4630 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4631 obj->maskwords_bm_gnu]; 4632 4633 /* Calculate modulus word size of gnu hash and its derivative */ 4634 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4635 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4636 4637 /* Filter out the "definitely not in set" queries */ 4638 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4639 return (ESRCH); 4640 4641 /* Locate hash chain and corresponding value element*/ 4642 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4643 if (bucket == 0) 4644 return (ESRCH); 4645 hashval = &obj->chain_zero_gnu[bucket]; 4646 do { 4647 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4648 symnum = hashval - obj->chain_zero_gnu; 4649 if (matched_symbol(req, obj, &matchres, symnum)) { 4650 req->sym_out = matchres.sym_out; 4651 req->defobj_out = obj; 4652 return (0); 4653 } 4654 } 4655 } while ((*hashval++ & 1) == 0); 4656 if (matchres.vcount == 1) { 4657 req->sym_out = matchres.vsymp; 4658 req->defobj_out = obj; 4659 return (0); 4660 } 4661 return (ESRCH); 4662 } 4663 4664 static void 4665 trace_loaded_objects(Obj_Entry *obj) 4666 { 4667 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4668 int c; 4669 4670 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL) 4671 main_local = ""; 4672 4673 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL) 4674 fmt1 = "\t%o => %p (%x)\n"; 4675 4676 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL) 4677 fmt2 = "\t%o (%x)\n"; 4678 4679 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL")); 4680 4681 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4682 Needed_Entry *needed; 4683 const char *name, *path; 4684 bool is_lib; 4685 4686 if (obj->marker) 4687 continue; 4688 if (list_containers && obj->needed != NULL) 4689 rtld_printf("%s:\n", obj->path); 4690 for (needed = obj->needed; needed; needed = needed->next) { 4691 if (needed->obj != NULL) { 4692 if (needed->obj->traced && !list_containers) 4693 continue; 4694 needed->obj->traced = true; 4695 path = needed->obj->path; 4696 } else 4697 path = "not found"; 4698 4699 name = obj->strtab + needed->name; 4700 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4701 4702 fmt = is_lib ? fmt1 : fmt2; 4703 while ((c = *fmt++) != '\0') { 4704 switch (c) { 4705 default: 4706 rtld_putchar(c); 4707 continue; 4708 case '\\': 4709 switch (c = *fmt) { 4710 case '\0': 4711 continue; 4712 case 'n': 4713 rtld_putchar('\n'); 4714 break; 4715 case 't': 4716 rtld_putchar('\t'); 4717 break; 4718 } 4719 break; 4720 case '%': 4721 switch (c = *fmt) { 4722 case '\0': 4723 continue; 4724 case '%': 4725 default: 4726 rtld_putchar(c); 4727 break; 4728 case 'A': 4729 rtld_putstr(main_local); 4730 break; 4731 case 'a': 4732 rtld_putstr(obj_main->path); 4733 break; 4734 case 'o': 4735 rtld_putstr(name); 4736 break; 4737 #if 0 4738 case 'm': 4739 rtld_printf("%d", sodp->sod_major); 4740 break; 4741 case 'n': 4742 rtld_printf("%d", sodp->sod_minor); 4743 break; 4744 #endif 4745 case 'p': 4746 rtld_putstr(path); 4747 break; 4748 case 'x': 4749 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4750 0); 4751 break; 4752 } 4753 break; 4754 } 4755 ++fmt; 4756 } 4757 } 4758 } 4759 } 4760 4761 /* 4762 * Unload a dlopened object and its dependencies from memory and from 4763 * our data structures. It is assumed that the DAG rooted in the 4764 * object has already been unreferenced, and that the object has a 4765 * reference count of 0. 4766 */ 4767 static void 4768 unload_object(Obj_Entry *root, RtldLockState *lockstate) 4769 { 4770 Obj_Entry marker, *obj, *next; 4771 4772 assert(root->refcount == 0); 4773 4774 /* 4775 * Pass over the DAG removing unreferenced objects from 4776 * appropriate lists. 4777 */ 4778 unlink_object(root); 4779 4780 /* Unmap all objects that are no longer referenced. */ 4781 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) { 4782 next = TAILQ_NEXT(obj, next); 4783 if (obj->marker || obj->refcount != 0) 4784 continue; 4785 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 4786 obj->mapsize, 0, obj->path); 4787 dbg("unloading \"%s\"", obj->path); 4788 /* 4789 * Unlink the object now to prevent new references from 4790 * being acquired while the bind lock is dropped in 4791 * recursive dlclose() invocations. 4792 */ 4793 TAILQ_REMOVE(&obj_list, obj, next); 4794 obj_count--; 4795 4796 if (obj->filtees_loaded) { 4797 if (next != NULL) { 4798 init_marker(&marker); 4799 TAILQ_INSERT_BEFORE(next, &marker, next); 4800 unload_filtees(obj, lockstate); 4801 next = TAILQ_NEXT(&marker, next); 4802 TAILQ_REMOVE(&obj_list, &marker, next); 4803 } else 4804 unload_filtees(obj, lockstate); 4805 } 4806 release_object(obj); 4807 } 4808 } 4809 4810 static void 4811 unlink_object(Obj_Entry *root) 4812 { 4813 Objlist_Entry *elm; 4814 4815 if (root->refcount == 0) { 4816 /* Remove the object from the RTLD_GLOBAL list. */ 4817 objlist_remove(&list_global, root); 4818 4819 /* Remove the object from all objects' DAG lists. */ 4820 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4821 objlist_remove(&elm->obj->dldags, root); 4822 if (elm->obj != root) 4823 unlink_object(elm->obj); 4824 } 4825 } 4826 } 4827 4828 static void 4829 ref_dag(Obj_Entry *root) 4830 { 4831 Objlist_Entry *elm; 4832 4833 assert(root->dag_inited); 4834 STAILQ_FOREACH(elm, &root->dagmembers, link) 4835 elm->obj->refcount++; 4836 } 4837 4838 static void 4839 unref_dag(Obj_Entry *root) 4840 { 4841 Objlist_Entry *elm; 4842 4843 assert(root->dag_inited); 4844 STAILQ_FOREACH(elm, &root->dagmembers, link) 4845 elm->obj->refcount--; 4846 } 4847 4848 /* 4849 * Common code for MD __tls_get_addr(). 4850 */ 4851 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4852 static void * 4853 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4854 { 4855 Elf_Addr *newdtv, *dtv; 4856 RtldLockState lockstate; 4857 int to_copy; 4858 4859 dtv = *dtvp; 4860 /* Check dtv generation in case new modules have arrived */ 4861 if (dtv[0] != tls_dtv_generation) { 4862 wlock_acquire(rtld_bind_lock, &lockstate); 4863 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4864 to_copy = dtv[1]; 4865 if (to_copy > tls_max_index) 4866 to_copy = tls_max_index; 4867 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4868 newdtv[0] = tls_dtv_generation; 4869 newdtv[1] = tls_max_index; 4870 free(dtv); 4871 lock_release(rtld_bind_lock, &lockstate); 4872 dtv = *dtvp = newdtv; 4873 } 4874 4875 /* Dynamically allocate module TLS if necessary */ 4876 if (dtv[index + 1] == 0) { 4877 /* Signal safe, wlock will block out signals. */ 4878 wlock_acquire(rtld_bind_lock, &lockstate); 4879 if (!dtv[index + 1]) 4880 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4881 lock_release(rtld_bind_lock, &lockstate); 4882 } 4883 return ((void *)(dtv[index + 1] + offset)); 4884 } 4885 4886 void * 4887 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4888 { 4889 Elf_Addr *dtv; 4890 4891 dtv = *dtvp; 4892 /* Check dtv generation in case new modules have arrived */ 4893 if (__predict_true(dtv[0] == tls_dtv_generation && 4894 dtv[index + 1] != 0)) 4895 return ((void *)(dtv[index + 1] + offset)); 4896 return (tls_get_addr_slow(dtvp, index, offset)); 4897 } 4898 4899 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \ 4900 defined(__powerpc__) || defined(__riscv) 4901 4902 /* 4903 * Return pointer to allocated TLS block 4904 */ 4905 static void * 4906 get_tls_block_ptr(void *tcb, size_t tcbsize) 4907 { 4908 size_t extra_size, post_size, pre_size, tls_block_size; 4909 size_t tls_init_align; 4910 4911 tls_init_align = MAX(obj_main->tlsalign, 1); 4912 4913 /* Compute fragments sizes. */ 4914 extra_size = tcbsize - TLS_TCB_SIZE; 4915 post_size = calculate_tls_post_size(tls_init_align); 4916 tls_block_size = tcbsize + post_size; 4917 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 4918 4919 return ((char *)tcb - pre_size - extra_size); 4920 } 4921 4922 /* 4923 * Allocate Static TLS using the Variant I method. 4924 * 4925 * For details on the layout, see lib/libc/gen/tls.c. 4926 * 4927 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as 4928 * it is based on tls_last_offset, and TLS offsets here are really TCB 4929 * offsets, whereas libc's tls_static_space is just the executable's static 4930 * TLS segment. 4931 */ 4932 void * 4933 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4934 { 4935 Obj_Entry *obj; 4936 char *tls_block; 4937 Elf_Addr *dtv, **tcb; 4938 Elf_Addr addr; 4939 Elf_Addr i; 4940 size_t extra_size, maxalign, post_size, pre_size, tls_block_size; 4941 size_t tls_init_align, tls_init_offset; 4942 4943 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4944 return (oldtcb); 4945 4946 assert(tcbsize >= TLS_TCB_SIZE); 4947 maxalign = MAX(tcbalign, tls_static_max_align); 4948 tls_init_align = MAX(obj_main->tlsalign, 1); 4949 4950 /* Compute fragmets sizes. */ 4951 extra_size = tcbsize - TLS_TCB_SIZE; 4952 post_size = calculate_tls_post_size(tls_init_align); 4953 tls_block_size = tcbsize + post_size; 4954 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 4955 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size; 4956 4957 /* Allocate whole TLS block */ 4958 tls_block = malloc_aligned(tls_block_size, maxalign, 0); 4959 tcb = (Elf_Addr **)(tls_block + pre_size + extra_size); 4960 4961 if (oldtcb != NULL) { 4962 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize), 4963 tls_static_space); 4964 free_aligned(get_tls_block_ptr(oldtcb, tcbsize)); 4965 4966 /* Adjust the DTV. */ 4967 dtv = tcb[0]; 4968 for (i = 0; i < dtv[1]; i++) { 4969 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4970 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4971 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tcb; 4972 } 4973 } 4974 } else { 4975 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4976 tcb[0] = dtv; 4977 dtv[0] = tls_dtv_generation; 4978 dtv[1] = tls_max_index; 4979 4980 for (obj = globallist_curr(objs); obj != NULL; 4981 obj = globallist_next(obj)) { 4982 if (obj->tlsoffset == 0) 4983 continue; 4984 tls_init_offset = obj->tlspoffset & (obj->tlsalign - 1); 4985 addr = (Elf_Addr)tcb + obj->tlsoffset; 4986 if (tls_init_offset > 0) 4987 memset((void *)addr, 0, tls_init_offset); 4988 if (obj->tlsinitsize > 0) { 4989 memcpy((void *)(addr + tls_init_offset), obj->tlsinit, 4990 obj->tlsinitsize); 4991 } 4992 if (obj->tlssize > obj->tlsinitsize) { 4993 memset((void *)(addr + tls_init_offset + obj->tlsinitsize), 4994 0, obj->tlssize - obj->tlsinitsize - tls_init_offset); 4995 } 4996 dtv[obj->tlsindex + 1] = addr; 4997 } 4998 } 4999 5000 return (tcb); 5001 } 5002 5003 void 5004 free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused) 5005 { 5006 Elf_Addr *dtv; 5007 Elf_Addr tlsstart, tlsend; 5008 size_t post_size; 5009 size_t dtvsize, i, tls_init_align; 5010 5011 assert(tcbsize >= TLS_TCB_SIZE); 5012 tls_init_align = MAX(obj_main->tlsalign, 1); 5013 5014 /* Compute fragments sizes. */ 5015 post_size = calculate_tls_post_size(tls_init_align); 5016 5017 tlsstart = (Elf_Addr)tcb + TLS_TCB_SIZE + post_size; 5018 tlsend = (Elf_Addr)tcb + tls_static_space; 5019 5020 dtv = *(Elf_Addr **)tcb; 5021 dtvsize = dtv[1]; 5022 for (i = 0; i < dtvsize; i++) { 5023 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 5024 free((void*)dtv[i+2]); 5025 } 5026 } 5027 free(dtv); 5028 free_aligned(get_tls_block_ptr(tcb, tcbsize)); 5029 } 5030 5031 #endif 5032 5033 #if defined(__i386__) || defined(__amd64__) 5034 5035 /* 5036 * Allocate Static TLS using the Variant II method. 5037 */ 5038 void * 5039 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 5040 { 5041 Obj_Entry *obj; 5042 size_t size, ralign; 5043 char *tls; 5044 Elf_Addr *dtv, *olddtv; 5045 Elf_Addr segbase, oldsegbase, addr; 5046 size_t i; 5047 5048 ralign = tcbalign; 5049 if (tls_static_max_align > ralign) 5050 ralign = tls_static_max_align; 5051 size = roundup(tls_static_space, ralign) + roundup(tcbsize, ralign); 5052 5053 assert(tcbsize >= 2*sizeof(Elf_Addr)); 5054 tls = malloc_aligned(size, ralign, 0 /* XXX */); 5055 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5056 5057 segbase = (Elf_Addr)(tls + roundup(tls_static_space, ralign)); 5058 ((Elf_Addr*)segbase)[0] = segbase; 5059 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 5060 5061 dtv[0] = tls_dtv_generation; 5062 dtv[1] = tls_max_index; 5063 5064 if (oldtls) { 5065 /* 5066 * Copy the static TLS block over whole. 5067 */ 5068 oldsegbase = (Elf_Addr) oldtls; 5069 memcpy((void *)(segbase - tls_static_space), 5070 (const void *)(oldsegbase - tls_static_space), 5071 tls_static_space); 5072 5073 /* 5074 * If any dynamic TLS blocks have been created tls_get_addr(), 5075 * move them over. 5076 */ 5077 olddtv = ((Elf_Addr**)oldsegbase)[1]; 5078 for (i = 0; i < olddtv[1]; i++) { 5079 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 5080 dtv[i+2] = olddtv[i+2]; 5081 olddtv[i+2] = 0; 5082 } 5083 } 5084 5085 /* 5086 * We assume that this block was the one we created with 5087 * allocate_initial_tls(). 5088 */ 5089 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 5090 } else { 5091 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 5092 if (obj->marker || obj->tlsoffset == 0) 5093 continue; 5094 addr = segbase - obj->tlsoffset; 5095 memset((void*)(addr + obj->tlsinitsize), 5096 0, obj->tlssize - obj->tlsinitsize); 5097 if (obj->tlsinit) { 5098 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 5099 obj->static_tls_copied = true; 5100 } 5101 dtv[obj->tlsindex + 1] = addr; 5102 } 5103 } 5104 5105 return (void*) segbase; 5106 } 5107 5108 void 5109 free_tls(void *tls, size_t tcbsize __unused, size_t tcbalign) 5110 { 5111 Elf_Addr* dtv; 5112 size_t size, ralign; 5113 int dtvsize, i; 5114 Elf_Addr tlsstart, tlsend; 5115 5116 /* 5117 * Figure out the size of the initial TLS block so that we can 5118 * find stuff which ___tls_get_addr() allocated dynamically. 5119 */ 5120 ralign = tcbalign; 5121 if (tls_static_max_align > ralign) 5122 ralign = tls_static_max_align; 5123 size = roundup(tls_static_space, ralign); 5124 5125 dtv = ((Elf_Addr**)tls)[1]; 5126 dtvsize = dtv[1]; 5127 tlsend = (Elf_Addr) tls; 5128 tlsstart = tlsend - size; 5129 for (i = 0; i < dtvsize; i++) { 5130 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 5131 free_aligned((void *)dtv[i + 2]); 5132 } 5133 } 5134 5135 free_aligned((void *)tlsstart); 5136 free((void*) dtv); 5137 } 5138 5139 #endif 5140 5141 /* 5142 * Allocate TLS block for module with given index. 5143 */ 5144 void * 5145 allocate_module_tls(int index) 5146 { 5147 Obj_Entry *obj; 5148 char *p; 5149 5150 TAILQ_FOREACH(obj, &obj_list, next) { 5151 if (obj->marker) 5152 continue; 5153 if (obj->tlsindex == index) 5154 break; 5155 } 5156 if (obj == NULL) { 5157 _rtld_error("Can't find module with TLS index %d", index); 5158 rtld_die(); 5159 } 5160 5161 p = malloc_aligned(obj->tlssize, obj->tlsalign, obj->tlspoffset); 5162 memcpy(p, obj->tlsinit, obj->tlsinitsize); 5163 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 5164 return (p); 5165 } 5166 5167 bool 5168 allocate_tls_offset(Obj_Entry *obj) 5169 { 5170 size_t off; 5171 5172 if (obj->tls_done) 5173 return true; 5174 5175 if (obj->tlssize == 0) { 5176 obj->tls_done = true; 5177 return true; 5178 } 5179 5180 if (tls_last_offset == 0) 5181 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign, 5182 obj->tlspoffset); 5183 else 5184 off = calculate_tls_offset(tls_last_offset, tls_last_size, 5185 obj->tlssize, obj->tlsalign, obj->tlspoffset); 5186 5187 /* 5188 * If we have already fixed the size of the static TLS block, we 5189 * must stay within that size. When allocating the static TLS, we 5190 * leave a small amount of space spare to be used for dynamically 5191 * loading modules which use static TLS. 5192 */ 5193 if (tls_static_space != 0) { 5194 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 5195 return false; 5196 } else if (obj->tlsalign > tls_static_max_align) { 5197 tls_static_max_align = obj->tlsalign; 5198 } 5199 5200 tls_last_offset = obj->tlsoffset = off; 5201 tls_last_size = obj->tlssize; 5202 obj->tls_done = true; 5203 5204 return true; 5205 } 5206 5207 void 5208 free_tls_offset(Obj_Entry *obj) 5209 { 5210 5211 /* 5212 * If we were the last thing to allocate out of the static TLS 5213 * block, we give our space back to the 'allocator'. This is a 5214 * simplistic workaround to allow libGL.so.1 to be loaded and 5215 * unloaded multiple times. 5216 */ 5217 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 5218 == calculate_tls_end(tls_last_offset, tls_last_size)) { 5219 tls_last_offset -= obj->tlssize; 5220 tls_last_size = 0; 5221 } 5222 } 5223 5224 void * 5225 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 5226 { 5227 void *ret; 5228 RtldLockState lockstate; 5229 5230 wlock_acquire(rtld_bind_lock, &lockstate); 5231 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 5232 tcbsize, tcbalign); 5233 lock_release(rtld_bind_lock, &lockstate); 5234 return (ret); 5235 } 5236 5237 void 5238 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 5239 { 5240 RtldLockState lockstate; 5241 5242 wlock_acquire(rtld_bind_lock, &lockstate); 5243 free_tls(tcb, tcbsize, tcbalign); 5244 lock_release(rtld_bind_lock, &lockstate); 5245 } 5246 5247 static void 5248 object_add_name(Obj_Entry *obj, const char *name) 5249 { 5250 Name_Entry *entry; 5251 size_t len; 5252 5253 len = strlen(name); 5254 entry = malloc(sizeof(Name_Entry) + len); 5255 5256 if (entry != NULL) { 5257 strcpy(entry->name, name); 5258 STAILQ_INSERT_TAIL(&obj->names, entry, link); 5259 } 5260 } 5261 5262 static int 5263 object_match_name(const Obj_Entry *obj, const char *name) 5264 { 5265 Name_Entry *entry; 5266 5267 STAILQ_FOREACH(entry, &obj->names, link) { 5268 if (strcmp(name, entry->name) == 0) 5269 return (1); 5270 } 5271 return (0); 5272 } 5273 5274 static Obj_Entry * 5275 locate_dependency(const Obj_Entry *obj, const char *name) 5276 { 5277 const Objlist_Entry *entry; 5278 const Needed_Entry *needed; 5279 5280 STAILQ_FOREACH(entry, &list_main, link) { 5281 if (object_match_name(entry->obj, name)) 5282 return entry->obj; 5283 } 5284 5285 for (needed = obj->needed; needed != NULL; needed = needed->next) { 5286 if (strcmp(obj->strtab + needed->name, name) == 0 || 5287 (needed->obj != NULL && object_match_name(needed->obj, name))) { 5288 /* 5289 * If there is DT_NEEDED for the name we are looking for, 5290 * we are all set. Note that object might not be found if 5291 * dependency was not loaded yet, so the function can 5292 * return NULL here. This is expected and handled 5293 * properly by the caller. 5294 */ 5295 return (needed->obj); 5296 } 5297 } 5298 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 5299 obj->path, name); 5300 rtld_die(); 5301 } 5302 5303 static int 5304 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 5305 const Elf_Vernaux *vna) 5306 { 5307 const Elf_Verdef *vd; 5308 const char *vername; 5309 5310 vername = refobj->strtab + vna->vna_name; 5311 vd = depobj->verdef; 5312 if (vd == NULL) { 5313 _rtld_error("%s: version %s required by %s not defined", 5314 depobj->path, vername, refobj->path); 5315 return (-1); 5316 } 5317 for (;;) { 5318 if (vd->vd_version != VER_DEF_CURRENT) { 5319 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5320 depobj->path, vd->vd_version); 5321 return (-1); 5322 } 5323 if (vna->vna_hash == vd->vd_hash) { 5324 const Elf_Verdaux *aux = (const Elf_Verdaux *) 5325 ((const char *)vd + vd->vd_aux); 5326 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 5327 return (0); 5328 } 5329 if (vd->vd_next == 0) 5330 break; 5331 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5332 } 5333 if (vna->vna_flags & VER_FLG_WEAK) 5334 return (0); 5335 _rtld_error("%s: version %s required by %s not found", 5336 depobj->path, vername, refobj->path); 5337 return (-1); 5338 } 5339 5340 static int 5341 rtld_verify_object_versions(Obj_Entry *obj) 5342 { 5343 const Elf_Verneed *vn; 5344 const Elf_Verdef *vd; 5345 const Elf_Verdaux *vda; 5346 const Elf_Vernaux *vna; 5347 const Obj_Entry *depobj; 5348 int maxvernum, vernum; 5349 5350 if (obj->ver_checked) 5351 return (0); 5352 obj->ver_checked = true; 5353 5354 maxvernum = 0; 5355 /* 5356 * Walk over defined and required version records and figure out 5357 * max index used by any of them. Do very basic sanity checking 5358 * while there. 5359 */ 5360 vn = obj->verneed; 5361 while (vn != NULL) { 5362 if (vn->vn_version != VER_NEED_CURRENT) { 5363 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 5364 obj->path, vn->vn_version); 5365 return (-1); 5366 } 5367 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5368 for (;;) { 5369 vernum = VER_NEED_IDX(vna->vna_other); 5370 if (vernum > maxvernum) 5371 maxvernum = vernum; 5372 if (vna->vna_next == 0) 5373 break; 5374 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5375 } 5376 if (vn->vn_next == 0) 5377 break; 5378 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5379 } 5380 5381 vd = obj->verdef; 5382 while (vd != NULL) { 5383 if (vd->vd_version != VER_DEF_CURRENT) { 5384 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5385 obj->path, vd->vd_version); 5386 return (-1); 5387 } 5388 vernum = VER_DEF_IDX(vd->vd_ndx); 5389 if (vernum > maxvernum) 5390 maxvernum = vernum; 5391 if (vd->vd_next == 0) 5392 break; 5393 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5394 } 5395 5396 if (maxvernum == 0) 5397 return (0); 5398 5399 /* 5400 * Store version information in array indexable by version index. 5401 * Verify that object version requirements are satisfied along the 5402 * way. 5403 */ 5404 obj->vernum = maxvernum + 1; 5405 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 5406 5407 vd = obj->verdef; 5408 while (vd != NULL) { 5409 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 5410 vernum = VER_DEF_IDX(vd->vd_ndx); 5411 assert(vernum <= maxvernum); 5412 vda = (const Elf_Verdaux *)((const char *)vd + vd->vd_aux); 5413 obj->vertab[vernum].hash = vd->vd_hash; 5414 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 5415 obj->vertab[vernum].file = NULL; 5416 obj->vertab[vernum].flags = 0; 5417 } 5418 if (vd->vd_next == 0) 5419 break; 5420 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5421 } 5422 5423 vn = obj->verneed; 5424 while (vn != NULL) { 5425 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 5426 if (depobj == NULL) 5427 return (-1); 5428 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5429 for (;;) { 5430 if (check_object_provided_version(obj, depobj, vna)) 5431 return (-1); 5432 vernum = VER_NEED_IDX(vna->vna_other); 5433 assert(vernum <= maxvernum); 5434 obj->vertab[vernum].hash = vna->vna_hash; 5435 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 5436 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 5437 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 5438 VER_INFO_HIDDEN : 0; 5439 if (vna->vna_next == 0) 5440 break; 5441 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5442 } 5443 if (vn->vn_next == 0) 5444 break; 5445 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5446 } 5447 return 0; 5448 } 5449 5450 static int 5451 rtld_verify_versions(const Objlist *objlist) 5452 { 5453 Objlist_Entry *entry; 5454 int rc; 5455 5456 rc = 0; 5457 STAILQ_FOREACH(entry, objlist, link) { 5458 /* 5459 * Skip dummy objects or objects that have their version requirements 5460 * already checked. 5461 */ 5462 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 5463 continue; 5464 if (rtld_verify_object_versions(entry->obj) == -1) { 5465 rc = -1; 5466 if (ld_tracing == NULL) 5467 break; 5468 } 5469 } 5470 if (rc == 0 || ld_tracing != NULL) 5471 rc = rtld_verify_object_versions(&obj_rtld); 5472 return rc; 5473 } 5474 5475 const Ver_Entry * 5476 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 5477 { 5478 Elf_Versym vernum; 5479 5480 if (obj->vertab) { 5481 vernum = VER_NDX(obj->versyms[symnum]); 5482 if (vernum >= obj->vernum) { 5483 _rtld_error("%s: symbol %s has wrong verneed value %d", 5484 obj->path, obj->strtab + symnum, vernum); 5485 } else if (obj->vertab[vernum].hash != 0) { 5486 return &obj->vertab[vernum]; 5487 } 5488 } 5489 return NULL; 5490 } 5491 5492 int 5493 _rtld_get_stack_prot(void) 5494 { 5495 5496 return (stack_prot); 5497 } 5498 5499 int 5500 _rtld_is_dlopened(void *arg) 5501 { 5502 Obj_Entry *obj; 5503 RtldLockState lockstate; 5504 int res; 5505 5506 rlock_acquire(rtld_bind_lock, &lockstate); 5507 obj = dlcheck(arg); 5508 if (obj == NULL) 5509 obj = obj_from_addr(arg); 5510 if (obj == NULL) { 5511 _rtld_error("No shared object contains address"); 5512 lock_release(rtld_bind_lock, &lockstate); 5513 return (-1); 5514 } 5515 res = obj->dlopened ? 1 : 0; 5516 lock_release(rtld_bind_lock, &lockstate); 5517 return (res); 5518 } 5519 5520 static int 5521 obj_remap_relro(Obj_Entry *obj, int prot) 5522 { 5523 5524 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size, 5525 prot) == -1) { 5526 _rtld_error("%s: Cannot set relro protection to %#x: %s", 5527 obj->path, prot, rtld_strerror(errno)); 5528 return (-1); 5529 } 5530 return (0); 5531 } 5532 5533 static int 5534 obj_disable_relro(Obj_Entry *obj) 5535 { 5536 5537 return (obj_remap_relro(obj, PROT_READ | PROT_WRITE)); 5538 } 5539 5540 static int 5541 obj_enforce_relro(Obj_Entry *obj) 5542 { 5543 5544 return (obj_remap_relro(obj, PROT_READ)); 5545 } 5546 5547 static void 5548 map_stacks_exec(RtldLockState *lockstate) 5549 { 5550 void (*thr_map_stacks_exec)(void); 5551 5552 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5553 return; 5554 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5555 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5556 if (thr_map_stacks_exec != NULL) { 5557 stack_prot |= PROT_EXEC; 5558 thr_map_stacks_exec(); 5559 } 5560 } 5561 5562 static void 5563 distribute_static_tls(Objlist *list, RtldLockState *lockstate) 5564 { 5565 Objlist_Entry *elm; 5566 Obj_Entry *obj; 5567 void (*distrib)(size_t, void *, size_t, size_t); 5568 5569 distrib = (void (*)(size_t, void *, size_t, size_t))(uintptr_t) 5570 get_program_var_addr("__pthread_distribute_static_tls", lockstate); 5571 if (distrib == NULL) 5572 return; 5573 STAILQ_FOREACH(elm, list, link) { 5574 obj = elm->obj; 5575 if (obj->marker || !obj->tls_done || obj->static_tls_copied) 5576 continue; 5577 distrib(obj->tlsoffset, obj->tlsinit, obj->tlsinitsize, 5578 obj->tlssize); 5579 obj->static_tls_copied = true; 5580 } 5581 } 5582 5583 void 5584 symlook_init(SymLook *dst, const char *name) 5585 { 5586 5587 bzero(dst, sizeof(*dst)); 5588 dst->name = name; 5589 dst->hash = elf_hash(name); 5590 dst->hash_gnu = gnu_hash(name); 5591 } 5592 5593 static void 5594 symlook_init_from_req(SymLook *dst, const SymLook *src) 5595 { 5596 5597 dst->name = src->name; 5598 dst->hash = src->hash; 5599 dst->hash_gnu = src->hash_gnu; 5600 dst->ventry = src->ventry; 5601 dst->flags = src->flags; 5602 dst->defobj_out = NULL; 5603 dst->sym_out = NULL; 5604 dst->lockstate = src->lockstate; 5605 } 5606 5607 static int 5608 open_binary_fd(const char *argv0, bool search_in_path, 5609 const char **binpath_res) 5610 { 5611 char *binpath, *pathenv, *pe, *res1; 5612 const char *res; 5613 int fd; 5614 5615 binpath = NULL; 5616 res = NULL; 5617 if (search_in_path && strchr(argv0, '/') == NULL) { 5618 binpath = xmalloc(PATH_MAX); 5619 pathenv = getenv("PATH"); 5620 if (pathenv == NULL) { 5621 _rtld_error("-p and no PATH environment variable"); 5622 rtld_die(); 5623 } 5624 pathenv = strdup(pathenv); 5625 if (pathenv == NULL) { 5626 _rtld_error("Cannot allocate memory"); 5627 rtld_die(); 5628 } 5629 fd = -1; 5630 errno = ENOENT; 5631 while ((pe = strsep(&pathenv, ":")) != NULL) { 5632 if (strlcpy(binpath, pe, PATH_MAX) >= PATH_MAX) 5633 continue; 5634 if (binpath[0] != '\0' && 5635 strlcat(binpath, "/", PATH_MAX) >= PATH_MAX) 5636 continue; 5637 if (strlcat(binpath, argv0, PATH_MAX) >= PATH_MAX) 5638 continue; 5639 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY); 5640 if (fd != -1 || errno != ENOENT) { 5641 res = binpath; 5642 break; 5643 } 5644 } 5645 free(pathenv); 5646 } else { 5647 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY); 5648 res = argv0; 5649 } 5650 5651 if (fd == -1) { 5652 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno)); 5653 rtld_die(); 5654 } 5655 if (res != NULL && res[0] != '/') { 5656 res1 = xmalloc(PATH_MAX); 5657 if (realpath(res, res1) != NULL) { 5658 if (res != argv0) 5659 free(__DECONST(char *, res)); 5660 res = res1; 5661 } else { 5662 free(res1); 5663 } 5664 } 5665 *binpath_res = res; 5666 return (fd); 5667 } 5668 5669 /* 5670 * Parse a set of command-line arguments. 5671 */ 5672 static int 5673 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp, 5674 const char **argv0) 5675 { 5676 const char *arg; 5677 char machine[64]; 5678 size_t sz; 5679 int arglen, fd, i, j, mib[2]; 5680 char opt; 5681 bool seen_b, seen_f; 5682 5683 dbg("Parsing command-line arguments"); 5684 *use_pathp = false; 5685 *fdp = -1; 5686 seen_b = seen_f = false; 5687 5688 for (i = 1; i < argc; i++ ) { 5689 arg = argv[i]; 5690 dbg("argv[%d]: '%s'", i, arg); 5691 5692 /* 5693 * rtld arguments end with an explicit "--" or with the first 5694 * non-prefixed argument. 5695 */ 5696 if (strcmp(arg, "--") == 0) { 5697 i++; 5698 break; 5699 } 5700 if (arg[0] != '-') 5701 break; 5702 5703 /* 5704 * All other arguments are single-character options that can 5705 * be combined, so we need to search through `arg` for them. 5706 */ 5707 arglen = strlen(arg); 5708 for (j = 1; j < arglen; j++) { 5709 opt = arg[j]; 5710 if (opt == 'h') { 5711 print_usage(argv[0]); 5712 _exit(0); 5713 } else if (opt == 'b') { 5714 if (seen_f) { 5715 _rtld_error("Both -b and -f specified"); 5716 rtld_die(); 5717 } 5718 i++; 5719 *argv0 = argv[i]; 5720 seen_b = true; 5721 break; 5722 } else if (opt == 'f') { 5723 if (seen_b) { 5724 _rtld_error("Both -b and -f specified"); 5725 rtld_die(); 5726 } 5727 5728 /* 5729 * -f XX can be used to specify a 5730 * descriptor for the binary named at 5731 * the command line (i.e., the later 5732 * argument will specify the process 5733 * name but the descriptor is what 5734 * will actually be executed). 5735 * 5736 * -f must be the last option in, e.g., -abcf. 5737 */ 5738 if (j != arglen - 1) { 5739 _rtld_error("Invalid options: %s", arg); 5740 rtld_die(); 5741 } 5742 i++; 5743 fd = parse_integer(argv[i]); 5744 if (fd == -1) { 5745 _rtld_error( 5746 "Invalid file descriptor: '%s'", 5747 argv[i]); 5748 rtld_die(); 5749 } 5750 *fdp = fd; 5751 seen_f = true; 5752 break; 5753 } else if (opt == 'p') { 5754 *use_pathp = true; 5755 } else if (opt == 'v') { 5756 machine[0] = '\0'; 5757 mib[0] = CTL_HW; 5758 mib[1] = HW_MACHINE; 5759 sz = sizeof(machine); 5760 sysctl(mib, nitems(mib), machine, &sz, NULL, 0); 5761 rtld_printf( 5762 "FreeBSD ld-elf.so.1 %s\n" 5763 "FreeBSD_version %d\n" 5764 "Default lib path %s\n" 5765 "Env prefix %s\n" 5766 "Hint file %s\n" 5767 "libmap file %s\n", 5768 machine, 5769 __FreeBSD_version, ld_standard_library_path, 5770 ld_env_prefix, ld_elf_hints_default, 5771 ld_path_libmap_conf); 5772 _exit(0); 5773 } else { 5774 _rtld_error("Invalid argument: '%s'", arg); 5775 print_usage(argv[0]); 5776 rtld_die(); 5777 } 5778 } 5779 } 5780 5781 if (!seen_b) 5782 *argv0 = argv[i]; 5783 return (i); 5784 } 5785 5786 /* 5787 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 5788 */ 5789 static int 5790 parse_integer(const char *str) 5791 { 5792 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 5793 const char *orig; 5794 int n; 5795 char c; 5796 5797 orig = str; 5798 n = 0; 5799 for (c = *str; c != '\0'; c = *++str) { 5800 if (c < '0' || c > '9') 5801 return (-1); 5802 5803 n *= RADIX; 5804 n += c - '0'; 5805 } 5806 5807 /* Make sure we actually parsed something. */ 5808 if (str == orig) 5809 return (-1); 5810 return (n); 5811 } 5812 5813 static void 5814 print_usage(const char *argv0) 5815 { 5816 5817 rtld_printf( 5818 "Usage: %s [-h] [-b <exe>] [-f <FD>] [-p] [--] <binary> [<args>]\n" 5819 "\n" 5820 "Options:\n" 5821 " -h Display this help message\n" 5822 " -b <exe> Execute <exe> instead of <binary>, arg0 is <binary>\n" 5823 " -f <FD> Execute <FD> instead of searching for <binary>\n" 5824 " -p Search in PATH for named binary\n" 5825 " -v Display identification information\n" 5826 " -- End of RTLD options\n" 5827 " <binary> Name of process to execute\n" 5828 " <args> Arguments to the executed process\n", argv0); 5829 } 5830 5831 /* 5832 * Overrides for libc_pic-provided functions. 5833 */ 5834 5835 int 5836 __getosreldate(void) 5837 { 5838 size_t len; 5839 int oid[2]; 5840 int error, osrel; 5841 5842 if (osreldate != 0) 5843 return (osreldate); 5844 5845 oid[0] = CTL_KERN; 5846 oid[1] = KERN_OSRELDATE; 5847 osrel = 0; 5848 len = sizeof(osrel); 5849 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 5850 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 5851 osreldate = osrel; 5852 return (osreldate); 5853 } 5854 const char * 5855 rtld_strerror(int errnum) 5856 { 5857 5858 if (errnum < 0 || errnum >= sys_nerr) 5859 return ("Unknown error"); 5860 return (sys_errlist[errnum]); 5861 } 5862 5863 /* malloc */ 5864 void * 5865 malloc(size_t nbytes) 5866 { 5867 5868 return (__crt_malloc(nbytes)); 5869 } 5870 5871 void * 5872 calloc(size_t num, size_t size) 5873 { 5874 5875 return (__crt_calloc(num, size)); 5876 } 5877 5878 void 5879 free(void *cp) 5880 { 5881 5882 __crt_free(cp); 5883 } 5884 5885 void * 5886 realloc(void *cp, size_t nbytes) 5887 { 5888 5889 return (__crt_realloc(cp, nbytes)); 5890 } 5891 5892 extern int _rtld_version__FreeBSD_version __exported; 5893 int _rtld_version__FreeBSD_version = __FreeBSD_version; 5894 5895 extern char _rtld_version_laddr_offset __exported; 5896 char _rtld_version_laddr_offset; 5897