1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra. 5 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>. 6 * Copyright 2009-2013 Konstantin Belousov <kib@FreeBSD.ORG>. 7 * Copyright 2012 John Marino <draco@marino.st>. 8 * Copyright 2014-2017 The FreeBSD Foundation 9 * All rights reserved. 10 * 11 * Portions of this software were developed by Konstantin Belousov 12 * under sponsorship from the FreeBSD Foundation. 13 * 14 * Redistribution and use in source and binary forms, with or without 15 * modification, are permitted provided that the following conditions 16 * are met: 17 * 1. Redistributions of source code must retain the above copyright 18 * notice, this list of conditions and the following disclaimer. 19 * 2. Redistributions in binary form must reproduce the above copyright 20 * notice, this list of conditions and the following disclaimer in the 21 * documentation and/or other materials provided with the distribution. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 25 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 26 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 27 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 28 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 29 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 30 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 31 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 32 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 33 */ 34 35 /* 36 * Dynamic linker for ELF. 37 * 38 * John Polstra <jdp@polstra.com>. 39 */ 40 41 #include <sys/cdefs.h> 42 __FBSDID("$FreeBSD$"); 43 44 #include <sys/param.h> 45 #include <sys/mount.h> 46 #include <sys/mman.h> 47 #include <sys/stat.h> 48 #include <sys/sysctl.h> 49 #include <sys/uio.h> 50 #include <sys/utsname.h> 51 #include <sys/ktrace.h> 52 53 #include <dlfcn.h> 54 #include <err.h> 55 #include <errno.h> 56 #include <fcntl.h> 57 #include <stdarg.h> 58 #include <stdio.h> 59 #include <stdlib.h> 60 #include <string.h> 61 #include <unistd.h> 62 63 #include "debug.h" 64 #include "rtld.h" 65 #include "libmap.h" 66 #include "paths.h" 67 #include "rtld_tls.h" 68 #include "rtld_printf.h" 69 #include "rtld_malloc.h" 70 #include "rtld_utrace.h" 71 #include "notes.h" 72 #include "rtld_libc.h" 73 74 /* Types. */ 75 typedef void (*func_ptr_type)(void); 76 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 77 78 79 /* Variables that cannot be static: */ 80 extern struct r_debug r_debug; /* For GDB */ 81 extern int _thread_autoinit_dummy_decl; 82 extern void (*__cleanup)(void); 83 84 85 /* 86 * Function declarations. 87 */ 88 static const char *basename(const char *); 89 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 90 const Elf_Dyn **, const Elf_Dyn **); 91 static bool digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *, 92 const Elf_Dyn *); 93 static bool digest_dynamic(Obj_Entry *, int); 94 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 95 static void distribute_static_tls(Objlist *, RtldLockState *); 96 static Obj_Entry *dlcheck(void *); 97 static int dlclose_locked(void *, RtldLockState *); 98 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, 99 int lo_flags, int mode, RtldLockState *lockstate); 100 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 101 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 102 static bool donelist_check(DoneList *, const Obj_Entry *); 103 static void errmsg_restore(char *); 104 static char *errmsg_save(void); 105 static void *fill_search_info(const char *, size_t, void *); 106 static char *find_library(const char *, const Obj_Entry *, int *); 107 static const char *gethints(bool); 108 static void hold_object(Obj_Entry *); 109 static void unhold_object(Obj_Entry *); 110 static void init_dag(Obj_Entry *); 111 static void init_marker(Obj_Entry *); 112 static void init_pagesizes(Elf_Auxinfo **aux_info); 113 static void init_rtld(caddr_t, Elf_Auxinfo **); 114 static void initlist_add_neededs(Needed_Entry *, Objlist *); 115 static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *); 116 static int initlist_objects_ifunc(Objlist *, bool, int, RtldLockState *); 117 static void linkmap_add(Obj_Entry *); 118 static void linkmap_delete(Obj_Entry *); 119 static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 120 static void unload_filtees(Obj_Entry *, RtldLockState *); 121 static int load_needed_objects(Obj_Entry *, int); 122 static int load_preload_objects(void); 123 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 124 static void map_stacks_exec(RtldLockState *); 125 static int obj_disable_relro(Obj_Entry *); 126 static int obj_enforce_relro(Obj_Entry *); 127 static Obj_Entry *obj_from_addr(const void *); 128 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 129 static void objlist_call_init(Objlist *, RtldLockState *); 130 static void objlist_clear(Objlist *); 131 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 132 static void objlist_init(Objlist *); 133 static void objlist_push_head(Objlist *, Obj_Entry *); 134 static void objlist_push_tail(Objlist *, Obj_Entry *); 135 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 136 static void objlist_remove(Objlist *, Obj_Entry *); 137 static int open_binary_fd(const char *argv0, bool search_in_path, 138 const char **binpath_res); 139 static int parse_args(char* argv[], int argc, bool *use_pathp, int *fdp, 140 const char **argv0); 141 static int parse_integer(const char *); 142 static void *path_enumerate(const char *, path_enum_proc, const char *, void *); 143 static void print_usage(const char *argv0); 144 static void release_object(Obj_Entry *); 145 static int relocate_object_dag(Obj_Entry *root, bool bind_now, 146 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 147 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 148 int flags, RtldLockState *lockstate); 149 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 150 RtldLockState *); 151 static int resolve_object_ifunc(Obj_Entry *, bool, int, RtldLockState *); 152 static int rtld_dirname(const char *, char *); 153 static int rtld_dirname_abs(const char *, char *); 154 static void *rtld_dlopen(const char *name, int fd, int mode); 155 static void rtld_exit(void); 156 static void rtld_nop_exit(void); 157 static char *search_library_path(const char *, const char *, const char *, 158 int *); 159 static char *search_library_pathfds(const char *, const char *, int *); 160 static const void **get_program_var_addr(const char *, RtldLockState *); 161 static void set_program_var(const char *, const void *); 162 static int symlook_default(SymLook *, const Obj_Entry *refobj); 163 static int symlook_global(SymLook *, DoneList *); 164 static void symlook_init_from_req(SymLook *, const SymLook *); 165 static int symlook_list(SymLook *, const Objlist *, DoneList *); 166 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 167 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 168 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 169 static void trace_loaded_objects(Obj_Entry *); 170 static void unlink_object(Obj_Entry *); 171 static void unload_object(Obj_Entry *, RtldLockState *lockstate); 172 static void unref_dag(Obj_Entry *); 173 static void ref_dag(Obj_Entry *); 174 static char *origin_subst_one(Obj_Entry *, char *, const char *, 175 const char *, bool); 176 static char *origin_subst(Obj_Entry *, const char *); 177 static bool obj_resolve_origin(Obj_Entry *obj); 178 static void preinit_main(void); 179 static int rtld_verify_versions(const Objlist *); 180 static int rtld_verify_object_versions(Obj_Entry *); 181 static void object_add_name(Obj_Entry *, const char *); 182 static int object_match_name(const Obj_Entry *, const char *); 183 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 184 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 185 struct dl_phdr_info *phdr_info); 186 static uint32_t gnu_hash(const char *); 187 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 188 const unsigned long); 189 190 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported; 191 void _r_debug_postinit(struct link_map *) __noinline __exported; 192 193 int __sys_openat(int, const char *, int, ...); 194 195 /* 196 * Data declarations. 197 */ 198 static char *error_message; /* Message for dlerror(), or NULL */ 199 struct r_debug r_debug __exported; /* for GDB; */ 200 static bool libmap_disable; /* Disable libmap */ 201 static bool ld_loadfltr; /* Immediate filters processing */ 202 static char *libmap_override; /* Maps to use in addition to libmap.conf */ 203 static bool trust; /* False for setuid and setgid programs */ 204 static bool dangerous_ld_env; /* True if environment variables have been 205 used to affect the libraries loaded */ 206 bool ld_bind_not; /* Disable PLT update */ 207 static char *ld_bind_now; /* Environment variable for immediate binding */ 208 static char *ld_debug; /* Environment variable for debugging */ 209 static char *ld_library_path; /* Environment variable for search path */ 210 static char *ld_library_dirs; /* Environment variable for library descriptors */ 211 static char *ld_preload; /* Environment variable for libraries to 212 load first */ 213 static const char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 214 static const char *ld_tracing; /* Called from ldd to print libs */ 215 static char *ld_utrace; /* Use utrace() to log events. */ 216 static struct obj_entry_q obj_list; /* Queue of all loaded objects */ 217 static Obj_Entry *obj_main; /* The main program shared object */ 218 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 219 static unsigned int obj_count; /* Number of objects in obj_list */ 220 static unsigned int obj_loads; /* Number of loads of objects (gen count) */ 221 222 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 223 STAILQ_HEAD_INITIALIZER(list_global); 224 static Objlist list_main = /* Objects loaded at program startup */ 225 STAILQ_HEAD_INITIALIZER(list_main); 226 static Objlist list_fini = /* Objects needing fini() calls */ 227 STAILQ_HEAD_INITIALIZER(list_fini); 228 229 Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 230 231 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 232 233 extern Elf_Dyn _DYNAMIC; 234 #pragma weak _DYNAMIC 235 236 int dlclose(void *) __exported; 237 char *dlerror(void) __exported; 238 void *dlopen(const char *, int) __exported; 239 void *fdlopen(int, int) __exported; 240 void *dlsym(void *, const char *) __exported; 241 dlfunc_t dlfunc(void *, const char *) __exported; 242 void *dlvsym(void *, const char *, const char *) __exported; 243 int dladdr(const void *, Dl_info *) __exported; 244 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *), 245 void (*)(void *), void (*)(void *), void (*)(void *)) __exported; 246 int dlinfo(void *, int , void *) __exported; 247 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported; 248 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported; 249 int _rtld_get_stack_prot(void) __exported; 250 int _rtld_is_dlopened(void *) __exported; 251 void _rtld_error(const char *, ...) __exported; 252 253 /* Only here to fix -Wmissing-prototypes warnings */ 254 int __getosreldate(void); 255 func_ptr_type _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp); 256 Elf_Addr _rtld_bind(Obj_Entry *obj, Elf_Size reloff); 257 258 259 int npagesizes; 260 static int osreldate; 261 size_t *pagesizes; 262 263 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 264 static int max_stack_flags; 265 266 /* 267 * Global declarations normally provided by crt1. The dynamic linker is 268 * not built with crt1, so we have to provide them ourselves. 269 */ 270 char *__progname; 271 char **environ; 272 273 /* 274 * Used to pass argc, argv to init functions. 275 */ 276 int main_argc; 277 char **main_argv; 278 279 /* 280 * Globals to control TLS allocation. 281 */ 282 size_t tls_last_offset; /* Static TLS offset of last module */ 283 size_t tls_last_size; /* Static TLS size of last module */ 284 size_t tls_static_space; /* Static TLS space allocated */ 285 static size_t tls_static_max_align; 286 Elf_Addr tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 287 int tls_max_index = 1; /* Largest module index allocated */ 288 289 static bool ld_library_path_rpath = false; 290 bool ld_fast_sigblock = false; 291 292 /* 293 * Globals for path names, and such 294 */ 295 const char *ld_elf_hints_default = _PATH_ELF_HINTS; 296 const char *ld_path_libmap_conf = _PATH_LIBMAP_CONF; 297 const char *ld_path_rtld = _PATH_RTLD; 298 const char *ld_standard_library_path = STANDARD_LIBRARY_PATH; 299 const char *ld_env_prefix = LD_; 300 301 static void (*rtld_exit_ptr)(void); 302 303 /* 304 * Fill in a DoneList with an allocation large enough to hold all of 305 * the currently-loaded objects. Keep this as a macro since it calls 306 * alloca and we want that to occur within the scope of the caller. 307 */ 308 #define donelist_init(dlp) \ 309 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 310 assert((dlp)->objs != NULL), \ 311 (dlp)->num_alloc = obj_count, \ 312 (dlp)->num_used = 0) 313 314 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 315 if (ld_utrace != NULL) \ 316 ld_utrace_log(e, h, mb, ms, r, n); \ 317 } while (0) 318 319 static void 320 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 321 int refcnt, const char *name) 322 { 323 struct utrace_rtld ut; 324 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG; 325 326 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig)); 327 ut.event = event; 328 ut.handle = handle; 329 ut.mapbase = mapbase; 330 ut.mapsize = mapsize; 331 ut.refcnt = refcnt; 332 bzero(ut.name, sizeof(ut.name)); 333 if (name) 334 strlcpy(ut.name, name, sizeof(ut.name)); 335 utrace(&ut, sizeof(ut)); 336 } 337 338 #ifdef RTLD_VARIANT_ENV_NAMES 339 /* 340 * construct the env variable based on the type of binary that's 341 * running. 342 */ 343 static inline const char * 344 _LD(const char *var) 345 { 346 static char buffer[128]; 347 348 strlcpy(buffer, ld_env_prefix, sizeof(buffer)); 349 strlcat(buffer, var, sizeof(buffer)); 350 return (buffer); 351 } 352 #else 353 #define _LD(x) LD_ x 354 #endif 355 356 /* 357 * Main entry point for dynamic linking. The first argument is the 358 * stack pointer. The stack is expected to be laid out as described 359 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 360 * Specifically, the stack pointer points to a word containing 361 * ARGC. Following that in the stack is a null-terminated sequence 362 * of pointers to argument strings. Then comes a null-terminated 363 * sequence of pointers to environment strings. Finally, there is a 364 * sequence of "auxiliary vector" entries. 365 * 366 * The second argument points to a place to store the dynamic linker's 367 * exit procedure pointer and the third to a place to store the main 368 * program's object. 369 * 370 * The return value is the main program's entry point. 371 */ 372 func_ptr_type 373 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 374 { 375 Elf_Auxinfo *aux, *auxp, *auxpf, *aux_info[AT_COUNT]; 376 Objlist_Entry *entry; 377 Obj_Entry *last_interposer, *obj, *preload_tail; 378 const Elf_Phdr *phdr; 379 Objlist initlist; 380 RtldLockState lockstate; 381 struct stat st; 382 Elf_Addr *argcp; 383 char **argv, **env, **envp, *kexecpath, *library_path_rpath; 384 const char *argv0, *binpath; 385 caddr_t imgentry; 386 char buf[MAXPATHLEN]; 387 int argc, fd, i, mib[4], old_osrel, osrel, phnum, rtld_argc; 388 size_t sz; 389 #ifdef __powerpc__ 390 int old_auxv_format = 1; 391 #endif 392 bool dir_enable, direct_exec, explicit_fd, search_in_path; 393 394 /* 395 * On entry, the dynamic linker itself has not been relocated yet. 396 * Be very careful not to reference any global data until after 397 * init_rtld has returned. It is OK to reference file-scope statics 398 * and string constants, and to call static and global functions. 399 */ 400 401 /* Find the auxiliary vector on the stack. */ 402 argcp = sp; 403 argc = *sp++; 404 argv = (char **) sp; 405 sp += argc + 1; /* Skip over arguments and NULL terminator */ 406 env = (char **) sp; 407 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 408 ; 409 aux = (Elf_Auxinfo *) sp; 410 411 /* Digest the auxiliary vector. */ 412 for (i = 0; i < AT_COUNT; i++) 413 aux_info[i] = NULL; 414 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 415 if (auxp->a_type < AT_COUNT) 416 aux_info[auxp->a_type] = auxp; 417 #ifdef __powerpc__ 418 if (auxp->a_type == 23) /* AT_STACKPROT */ 419 old_auxv_format = 0; 420 #endif 421 } 422 423 #ifdef __powerpc__ 424 if (old_auxv_format) { 425 /* Remap from old-style auxv numbers. */ 426 aux_info[23] = aux_info[21]; /* AT_STACKPROT */ 427 aux_info[21] = aux_info[19]; /* AT_PAGESIZESLEN */ 428 aux_info[19] = aux_info[17]; /* AT_NCPUS */ 429 aux_info[17] = aux_info[15]; /* AT_CANARYLEN */ 430 aux_info[15] = aux_info[13]; /* AT_EXECPATH */ 431 aux_info[13] = NULL; /* AT_GID */ 432 433 aux_info[20] = aux_info[18]; /* AT_PAGESIZES */ 434 aux_info[18] = aux_info[16]; /* AT_OSRELDATE */ 435 aux_info[16] = aux_info[14]; /* AT_CANARY */ 436 aux_info[14] = NULL; /* AT_EGID */ 437 } 438 #endif 439 440 /* Initialize and relocate ourselves. */ 441 assert(aux_info[AT_BASE] != NULL); 442 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 443 444 __progname = obj_rtld.path; 445 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 446 environ = env; 447 main_argc = argc; 448 main_argv = argv; 449 450 if (aux_info[AT_BSDFLAGS] != NULL && 451 (aux_info[AT_BSDFLAGS]->a_un.a_val & ELF_BSDF_SIGFASTBLK) != 0) 452 ld_fast_sigblock = true; 453 454 trust = !issetugid(); 455 direct_exec = false; 456 457 md_abi_variant_hook(aux_info); 458 459 fd = -1; 460 if (aux_info[AT_EXECFD] != NULL) { 461 fd = aux_info[AT_EXECFD]->a_un.a_val; 462 } else { 463 assert(aux_info[AT_PHDR] != NULL); 464 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr; 465 if (phdr == obj_rtld.phdr) { 466 if (!trust) { 467 _rtld_error("Tainted process refusing to run binary %s", 468 argv0); 469 rtld_die(); 470 } 471 direct_exec = true; 472 473 dbg("opening main program in direct exec mode"); 474 if (argc >= 2) { 475 rtld_argc = parse_args(argv, argc, &search_in_path, &fd, &argv0); 476 explicit_fd = (fd != -1); 477 binpath = NULL; 478 if (!explicit_fd) 479 fd = open_binary_fd(argv0, search_in_path, &binpath); 480 if (fstat(fd, &st) == -1) { 481 _rtld_error("Failed to fstat FD %d (%s): %s", fd, 482 explicit_fd ? "user-provided descriptor" : argv0, 483 rtld_strerror(errno)); 484 rtld_die(); 485 } 486 487 /* 488 * Rough emulation of the permission checks done by 489 * execve(2), only Unix DACs are checked, ACLs are 490 * ignored. Preserve the semantic of disabling owner 491 * to execute if owner x bit is cleared, even if 492 * others x bit is enabled. 493 * mmap(2) does not allow to mmap with PROT_EXEC if 494 * binary' file comes from noexec mount. We cannot 495 * set a text reference on the binary. 496 */ 497 dir_enable = false; 498 if (st.st_uid == geteuid()) { 499 if ((st.st_mode & S_IXUSR) != 0) 500 dir_enable = true; 501 } else if (st.st_gid == getegid()) { 502 if ((st.st_mode & S_IXGRP) != 0) 503 dir_enable = true; 504 } else if ((st.st_mode & S_IXOTH) != 0) { 505 dir_enable = true; 506 } 507 if (!dir_enable) { 508 _rtld_error("No execute permission for binary %s", 509 argv0); 510 rtld_die(); 511 } 512 513 /* 514 * For direct exec mode, argv[0] is the interpreter 515 * name, we must remove it and shift arguments left 516 * before invoking binary main. Since stack layout 517 * places environment pointers and aux vectors right 518 * after the terminating NULL, we must shift 519 * environment and aux as well. 520 */ 521 main_argc = argc - rtld_argc; 522 for (i = 0; i <= main_argc; i++) 523 argv[i] = argv[i + rtld_argc]; 524 *argcp -= rtld_argc; 525 environ = env = envp = argv + main_argc + 1; 526 dbg("move env from %p to %p", envp + rtld_argc, envp); 527 do { 528 *envp = *(envp + rtld_argc); 529 } while (*envp++ != NULL); 530 aux = auxp = (Elf_Auxinfo *)envp; 531 auxpf = (Elf_Auxinfo *)(envp + rtld_argc); 532 dbg("move aux from %p to %p", auxpf, aux); 533 /* XXXKIB insert place for AT_EXECPATH if not present */ 534 for (;; auxp++, auxpf++) { 535 *auxp = *auxpf; 536 if (auxp->a_type == AT_NULL) 537 break; 538 } 539 /* Since the auxiliary vector has moved, redigest it. */ 540 for (i = 0; i < AT_COUNT; i++) 541 aux_info[i] = NULL; 542 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 543 if (auxp->a_type < AT_COUNT) 544 aux_info[auxp->a_type] = auxp; 545 } 546 547 /* Point AT_EXECPATH auxv and aux_info to the binary path. */ 548 if (binpath == NULL) { 549 aux_info[AT_EXECPATH] = NULL; 550 } else { 551 if (aux_info[AT_EXECPATH] == NULL) { 552 aux_info[AT_EXECPATH] = xmalloc(sizeof(Elf_Auxinfo)); 553 aux_info[AT_EXECPATH]->a_type = AT_EXECPATH; 554 } 555 aux_info[AT_EXECPATH]->a_un.a_ptr = __DECONST(void *, 556 binpath); 557 } 558 } else { 559 _rtld_error("No binary"); 560 rtld_die(); 561 } 562 } 563 } 564 565 ld_bind_now = getenv(_LD("BIND_NOW")); 566 567 /* 568 * If the process is tainted, then we un-set the dangerous environment 569 * variables. The process will be marked as tainted until setuid(2) 570 * is called. If any child process calls setuid(2) we do not want any 571 * future processes to honor the potentially un-safe variables. 572 */ 573 if (!trust) { 574 if (unsetenv(_LD("PRELOAD")) || unsetenv(_LD("LIBMAP")) || 575 unsetenv(_LD("LIBRARY_PATH")) || unsetenv(_LD("LIBRARY_PATH_FDS")) || 576 unsetenv(_LD("LIBMAP_DISABLE")) || unsetenv(_LD("BIND_NOT")) || 577 unsetenv(_LD("DEBUG")) || unsetenv(_LD("ELF_HINTS_PATH")) || 578 unsetenv(_LD("LOADFLTR")) || unsetenv(_LD("LIBRARY_PATH_RPATH"))) { 579 _rtld_error("environment corrupt; aborting"); 580 rtld_die(); 581 } 582 } 583 ld_debug = getenv(_LD("DEBUG")); 584 if (ld_bind_now == NULL) 585 ld_bind_not = getenv(_LD("BIND_NOT")) != NULL; 586 libmap_disable = getenv(_LD("LIBMAP_DISABLE")) != NULL; 587 libmap_override = getenv(_LD("LIBMAP")); 588 ld_library_path = getenv(_LD("LIBRARY_PATH")); 589 ld_library_dirs = getenv(_LD("LIBRARY_PATH_FDS")); 590 ld_preload = getenv(_LD("PRELOAD")); 591 ld_elf_hints_path = getenv(_LD("ELF_HINTS_PATH")); 592 ld_loadfltr = getenv(_LD("LOADFLTR")) != NULL; 593 library_path_rpath = getenv(_LD("LIBRARY_PATH_RPATH")); 594 if (library_path_rpath != NULL) { 595 if (library_path_rpath[0] == 'y' || 596 library_path_rpath[0] == 'Y' || 597 library_path_rpath[0] == '1') 598 ld_library_path_rpath = true; 599 else 600 ld_library_path_rpath = false; 601 } 602 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 603 (ld_library_path != NULL) || (ld_preload != NULL) || 604 (ld_elf_hints_path != NULL) || ld_loadfltr; 605 ld_tracing = getenv(_LD("TRACE_LOADED_OBJECTS")); 606 ld_utrace = getenv(_LD("UTRACE")); 607 608 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 609 ld_elf_hints_path = ld_elf_hints_default; 610 611 if (ld_debug != NULL && *ld_debug != '\0') 612 debug = 1; 613 dbg("%s is initialized, base address = %p", __progname, 614 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 615 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 616 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 617 618 dbg("initializing thread locks"); 619 lockdflt_init(); 620 621 /* 622 * Load the main program, or process its program header if it is 623 * already loaded. 624 */ 625 if (fd != -1) { /* Load the main program. */ 626 dbg("loading main program"); 627 obj_main = map_object(fd, argv0, NULL); 628 close(fd); 629 if (obj_main == NULL) 630 rtld_die(); 631 max_stack_flags = obj_main->stack_flags; 632 } else { /* Main program already loaded. */ 633 dbg("processing main program's program header"); 634 assert(aux_info[AT_PHDR] != NULL); 635 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 636 assert(aux_info[AT_PHNUM] != NULL); 637 phnum = aux_info[AT_PHNUM]->a_un.a_val; 638 assert(aux_info[AT_PHENT] != NULL); 639 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 640 assert(aux_info[AT_ENTRY] != NULL); 641 imgentry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 642 if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) == NULL) 643 rtld_die(); 644 } 645 646 if (aux_info[AT_EXECPATH] != NULL && fd == -1) { 647 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 648 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 649 if (kexecpath[0] == '/') 650 obj_main->path = kexecpath; 651 else if (getcwd(buf, sizeof(buf)) == NULL || 652 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 653 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 654 obj_main->path = xstrdup(argv0); 655 else 656 obj_main->path = xstrdup(buf); 657 } else { 658 dbg("No AT_EXECPATH or direct exec"); 659 obj_main->path = xstrdup(argv0); 660 } 661 dbg("obj_main path %s", obj_main->path); 662 obj_main->mainprog = true; 663 664 if (aux_info[AT_STACKPROT] != NULL && 665 aux_info[AT_STACKPROT]->a_un.a_val != 0) 666 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 667 668 #ifndef COMPAT_32BIT 669 /* 670 * Get the actual dynamic linker pathname from the executable if 671 * possible. (It should always be possible.) That ensures that 672 * gdb will find the right dynamic linker even if a non-standard 673 * one is being used. 674 */ 675 if (obj_main->interp != NULL && 676 strcmp(obj_main->interp, obj_rtld.path) != 0) { 677 free(obj_rtld.path); 678 obj_rtld.path = xstrdup(obj_main->interp); 679 __progname = obj_rtld.path; 680 } 681 #endif 682 683 if (!digest_dynamic(obj_main, 0)) 684 rtld_die(); 685 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 686 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 687 obj_main->dynsymcount); 688 689 linkmap_add(obj_main); 690 linkmap_add(&obj_rtld); 691 692 /* Link the main program into the list of objects. */ 693 TAILQ_INSERT_HEAD(&obj_list, obj_main, next); 694 obj_count++; 695 obj_loads++; 696 697 /* Initialize a fake symbol for resolving undefined weak references. */ 698 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 699 sym_zero.st_shndx = SHN_UNDEF; 700 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 701 702 if (!libmap_disable) 703 libmap_disable = (bool)lm_init(libmap_override); 704 705 dbg("loading LD_PRELOAD libraries"); 706 if (load_preload_objects() == -1) 707 rtld_die(); 708 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 709 710 dbg("loading needed objects"); 711 if (load_needed_objects(obj_main, ld_tracing != NULL ? RTLD_LO_TRACE : 712 0) == -1) 713 rtld_die(); 714 715 /* Make a list of all objects loaded at startup. */ 716 last_interposer = obj_main; 717 TAILQ_FOREACH(obj, &obj_list, next) { 718 if (obj->marker) 719 continue; 720 if (obj->z_interpose && obj != obj_main) { 721 objlist_put_after(&list_main, last_interposer, obj); 722 last_interposer = obj; 723 } else { 724 objlist_push_tail(&list_main, obj); 725 } 726 obj->refcount++; 727 } 728 729 dbg("checking for required versions"); 730 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 731 rtld_die(); 732 733 if (ld_tracing) { /* We're done */ 734 trace_loaded_objects(obj_main); 735 exit(0); 736 } 737 738 if (getenv(_LD("DUMP_REL_PRE")) != NULL) { 739 dump_relocations(obj_main); 740 exit (0); 741 } 742 743 /* 744 * Processing tls relocations requires having the tls offsets 745 * initialized. Prepare offsets before starting initial 746 * relocation processing. 747 */ 748 dbg("initializing initial thread local storage offsets"); 749 STAILQ_FOREACH(entry, &list_main, link) { 750 /* 751 * Allocate all the initial objects out of the static TLS 752 * block even if they didn't ask for it. 753 */ 754 allocate_tls_offset(entry->obj); 755 } 756 757 if (relocate_objects(obj_main, 758 ld_bind_now != NULL && *ld_bind_now != '\0', 759 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 760 rtld_die(); 761 762 dbg("doing copy relocations"); 763 if (do_copy_relocations(obj_main) == -1) 764 rtld_die(); 765 766 if (getenv(_LD("DUMP_REL_POST")) != NULL) { 767 dump_relocations(obj_main); 768 exit (0); 769 } 770 771 ifunc_init(aux); 772 773 /* 774 * Setup TLS for main thread. This must be done after the 775 * relocations are processed, since tls initialization section 776 * might be the subject for relocations. 777 */ 778 dbg("initializing initial thread local storage"); 779 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list))); 780 781 dbg("initializing key program variables"); 782 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 783 set_program_var("environ", env); 784 set_program_var("__elf_aux_vector", aux); 785 786 /* Make a list of init functions to call. */ 787 objlist_init(&initlist); 788 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)), 789 preload_tail, &initlist); 790 791 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 792 793 map_stacks_exec(NULL); 794 795 if (!obj_main->crt_no_init) { 796 /* 797 * Make sure we don't call the main program's init and fini 798 * functions for binaries linked with old crt1 which calls 799 * _init itself. 800 */ 801 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 802 obj_main->preinit_array = obj_main->init_array = 803 obj_main->fini_array = (Elf_Addr)NULL; 804 } 805 806 /* 807 * Execute MD initializers required before we call the objects' 808 * init functions. 809 */ 810 pre_init(); 811 812 if (direct_exec) { 813 /* Set osrel for direct-execed binary */ 814 mib[0] = CTL_KERN; 815 mib[1] = KERN_PROC; 816 mib[2] = KERN_PROC_OSREL; 817 mib[3] = getpid(); 818 osrel = obj_main->osrel; 819 sz = sizeof(old_osrel); 820 dbg("setting osrel to %d", osrel); 821 (void)sysctl(mib, 4, &old_osrel, &sz, &osrel, sizeof(osrel)); 822 } 823 824 wlock_acquire(rtld_bind_lock, &lockstate); 825 826 dbg("resolving ifuncs"); 827 if (initlist_objects_ifunc(&initlist, ld_bind_now != NULL && 828 *ld_bind_now != '\0', SYMLOOK_EARLY, &lockstate) == -1) 829 rtld_die(); 830 831 rtld_exit_ptr = rtld_exit; 832 if (obj_main->crt_no_init) 833 preinit_main(); 834 objlist_call_init(&initlist, &lockstate); 835 _r_debug_postinit(&obj_main->linkmap); 836 objlist_clear(&initlist); 837 dbg("loading filtees"); 838 TAILQ_FOREACH(obj, &obj_list, next) { 839 if (obj->marker) 840 continue; 841 if (ld_loadfltr || obj->z_loadfltr) 842 load_filtees(obj, 0, &lockstate); 843 } 844 845 dbg("enforcing main obj relro"); 846 if (obj_enforce_relro(obj_main) == -1) 847 rtld_die(); 848 849 lock_release(rtld_bind_lock, &lockstate); 850 851 dbg("transferring control to program entry point = %p", obj_main->entry); 852 853 /* Return the exit procedure and the program entry point. */ 854 *exit_proc = rtld_exit_ptr; 855 *objp = obj_main; 856 return (func_ptr_type) obj_main->entry; 857 } 858 859 void * 860 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 861 { 862 void *ptr; 863 Elf_Addr target; 864 865 ptr = (void *)make_function_pointer(def, obj); 866 target = call_ifunc_resolver(ptr); 867 return ((void *)target); 868 } 869 870 /* 871 * NB: MIPS uses a private version of this function (_mips_rtld_bind). 872 * Changes to this function should be applied there as well. 873 */ 874 Elf_Addr 875 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 876 { 877 const Elf_Rel *rel; 878 const Elf_Sym *def; 879 const Obj_Entry *defobj; 880 Elf_Addr *where; 881 Elf_Addr target; 882 RtldLockState lockstate; 883 884 rlock_acquire(rtld_bind_lock, &lockstate); 885 if (sigsetjmp(lockstate.env, 0) != 0) 886 lock_upgrade(rtld_bind_lock, &lockstate); 887 if (obj->pltrel) 888 rel = (const Elf_Rel *)((const char *)obj->pltrel + reloff); 889 else 890 rel = (const Elf_Rel *)((const char *)obj->pltrela + reloff); 891 892 where = (Elf_Addr *)(obj->relocbase + rel->r_offset); 893 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT, 894 NULL, &lockstate); 895 if (def == NULL) 896 rtld_die(); 897 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 898 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 899 else 900 target = (Elf_Addr)(defobj->relocbase + def->st_value); 901 902 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 903 defobj->strtab + def->st_name, basename(obj->path), 904 (void *)target, basename(defobj->path)); 905 906 /* 907 * Write the new contents for the jmpslot. Note that depending on 908 * architecture, the value which we need to return back to the 909 * lazy binding trampoline may or may not be the target 910 * address. The value returned from reloc_jmpslot() is the value 911 * that the trampoline needs. 912 */ 913 target = reloc_jmpslot(where, target, defobj, obj, rel); 914 lock_release(rtld_bind_lock, &lockstate); 915 return target; 916 } 917 918 /* 919 * Error reporting function. Use it like printf. If formats the message 920 * into a buffer, and sets things up so that the next call to dlerror() 921 * will return the message. 922 */ 923 void 924 _rtld_error(const char *fmt, ...) 925 { 926 static char buf[512]; 927 va_list ap; 928 929 va_start(ap, fmt); 930 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 931 error_message = buf; 932 va_end(ap); 933 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, error_message); 934 } 935 936 /* 937 * Return a dynamically-allocated copy of the current error message, if any. 938 */ 939 static char * 940 errmsg_save(void) 941 { 942 return error_message == NULL ? NULL : xstrdup(error_message); 943 } 944 945 /* 946 * Restore the current error message from a copy which was previously saved 947 * by errmsg_save(). The copy is freed. 948 */ 949 static void 950 errmsg_restore(char *saved_msg) 951 { 952 if (saved_msg == NULL) 953 error_message = NULL; 954 else { 955 _rtld_error("%s", saved_msg); 956 free(saved_msg); 957 } 958 } 959 960 static const char * 961 basename(const char *name) 962 { 963 const char *p = strrchr(name, '/'); 964 return p != NULL ? p + 1 : name; 965 } 966 967 static struct utsname uts; 968 969 static char * 970 origin_subst_one(Obj_Entry *obj, char *real, const char *kw, 971 const char *subst, bool may_free) 972 { 973 char *p, *p1, *res, *resp; 974 int subst_len, kw_len, subst_count, old_len, new_len; 975 976 kw_len = strlen(kw); 977 978 /* 979 * First, count the number of the keyword occurrences, to 980 * preallocate the final string. 981 */ 982 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 983 p1 = strstr(p, kw); 984 if (p1 == NULL) 985 break; 986 } 987 988 /* 989 * If the keyword is not found, just return. 990 * 991 * Return non-substituted string if resolution failed. We 992 * cannot do anything more reasonable, the failure mode of the 993 * caller is unresolved library anyway. 994 */ 995 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj))) 996 return (may_free ? real : xstrdup(real)); 997 if (obj != NULL) 998 subst = obj->origin_path; 999 1000 /* 1001 * There is indeed something to substitute. Calculate the 1002 * length of the resulting string, and allocate it. 1003 */ 1004 subst_len = strlen(subst); 1005 old_len = strlen(real); 1006 new_len = old_len + (subst_len - kw_len) * subst_count; 1007 res = xmalloc(new_len + 1); 1008 1009 /* 1010 * Now, execute the substitution loop. 1011 */ 1012 for (p = real, resp = res, *resp = '\0';;) { 1013 p1 = strstr(p, kw); 1014 if (p1 != NULL) { 1015 /* Copy the prefix before keyword. */ 1016 memcpy(resp, p, p1 - p); 1017 resp += p1 - p; 1018 /* Keyword replacement. */ 1019 memcpy(resp, subst, subst_len); 1020 resp += subst_len; 1021 *resp = '\0'; 1022 p = p1 + kw_len; 1023 } else 1024 break; 1025 } 1026 1027 /* Copy to the end of string and finish. */ 1028 strcat(resp, p); 1029 if (may_free) 1030 free(real); 1031 return (res); 1032 } 1033 1034 static char * 1035 origin_subst(Obj_Entry *obj, const char *real) 1036 { 1037 char *res1, *res2, *res3, *res4; 1038 1039 if (obj == NULL || !trust) 1040 return (xstrdup(real)); 1041 if (uts.sysname[0] == '\0') { 1042 if (uname(&uts) != 0) { 1043 _rtld_error("utsname failed: %d", errno); 1044 return (NULL); 1045 } 1046 } 1047 /* __DECONST is safe here since without may_free real is unchanged */ 1048 res1 = origin_subst_one(obj, __DECONST(char *, real), "$ORIGIN", NULL, 1049 false); 1050 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true); 1051 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true); 1052 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true); 1053 return (res4); 1054 } 1055 1056 void 1057 rtld_die(void) 1058 { 1059 const char *msg = dlerror(); 1060 1061 if (msg == NULL) 1062 msg = "Fatal error"; 1063 rtld_fdputstr(STDERR_FILENO, _BASENAME_RTLD ": "); 1064 rtld_fdputstr(STDERR_FILENO, msg); 1065 rtld_fdputchar(STDERR_FILENO, '\n'); 1066 _exit(1); 1067 } 1068 1069 /* 1070 * Process a shared object's DYNAMIC section, and save the important 1071 * information in its Obj_Entry structure. 1072 */ 1073 static void 1074 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 1075 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 1076 { 1077 const Elf_Dyn *dynp; 1078 Needed_Entry **needed_tail = &obj->needed; 1079 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 1080 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 1081 const Elf_Hashelt *hashtab; 1082 const Elf32_Word *hashval; 1083 Elf32_Word bkt, nmaskwords; 1084 int bloom_size32; 1085 int plttype = DT_REL; 1086 1087 *dyn_rpath = NULL; 1088 *dyn_soname = NULL; 1089 *dyn_runpath = NULL; 1090 1091 obj->bind_now = false; 1092 dynp = obj->dynamic; 1093 if (dynp == NULL) 1094 return; 1095 for (; dynp->d_tag != DT_NULL; dynp++) { 1096 switch (dynp->d_tag) { 1097 1098 case DT_REL: 1099 obj->rel = (const Elf_Rel *)(obj->relocbase + dynp->d_un.d_ptr); 1100 break; 1101 1102 case DT_RELSZ: 1103 obj->relsize = dynp->d_un.d_val; 1104 break; 1105 1106 case DT_RELENT: 1107 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 1108 break; 1109 1110 case DT_JMPREL: 1111 obj->pltrel = (const Elf_Rel *) 1112 (obj->relocbase + dynp->d_un.d_ptr); 1113 break; 1114 1115 case DT_PLTRELSZ: 1116 obj->pltrelsize = dynp->d_un.d_val; 1117 break; 1118 1119 case DT_RELA: 1120 obj->rela = (const Elf_Rela *)(obj->relocbase + dynp->d_un.d_ptr); 1121 break; 1122 1123 case DT_RELASZ: 1124 obj->relasize = dynp->d_un.d_val; 1125 break; 1126 1127 case DT_RELAENT: 1128 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 1129 break; 1130 1131 case DT_PLTREL: 1132 plttype = dynp->d_un.d_val; 1133 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 1134 break; 1135 1136 case DT_SYMTAB: 1137 obj->symtab = (const Elf_Sym *) 1138 (obj->relocbase + dynp->d_un.d_ptr); 1139 break; 1140 1141 case DT_SYMENT: 1142 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 1143 break; 1144 1145 case DT_STRTAB: 1146 obj->strtab = (const char *)(obj->relocbase + dynp->d_un.d_ptr); 1147 break; 1148 1149 case DT_STRSZ: 1150 obj->strsize = dynp->d_un.d_val; 1151 break; 1152 1153 case DT_VERNEED: 1154 obj->verneed = (const Elf_Verneed *)(obj->relocbase + 1155 dynp->d_un.d_val); 1156 break; 1157 1158 case DT_VERNEEDNUM: 1159 obj->verneednum = dynp->d_un.d_val; 1160 break; 1161 1162 case DT_VERDEF: 1163 obj->verdef = (const Elf_Verdef *)(obj->relocbase + 1164 dynp->d_un.d_val); 1165 break; 1166 1167 case DT_VERDEFNUM: 1168 obj->verdefnum = dynp->d_un.d_val; 1169 break; 1170 1171 case DT_VERSYM: 1172 obj->versyms = (const Elf_Versym *)(obj->relocbase + 1173 dynp->d_un.d_val); 1174 break; 1175 1176 case DT_HASH: 1177 { 1178 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1179 dynp->d_un.d_ptr); 1180 obj->nbuckets = hashtab[0]; 1181 obj->nchains = hashtab[1]; 1182 obj->buckets = hashtab + 2; 1183 obj->chains = obj->buckets + obj->nbuckets; 1184 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 1185 obj->buckets != NULL; 1186 } 1187 break; 1188 1189 case DT_GNU_HASH: 1190 { 1191 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1192 dynp->d_un.d_ptr); 1193 obj->nbuckets_gnu = hashtab[0]; 1194 obj->symndx_gnu = hashtab[1]; 1195 nmaskwords = hashtab[2]; 1196 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1197 obj->maskwords_bm_gnu = nmaskwords - 1; 1198 obj->shift2_gnu = hashtab[3]; 1199 obj->bloom_gnu = (const Elf_Addr *)(hashtab + 4); 1200 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1201 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1202 obj->symndx_gnu; 1203 /* Number of bitmask words is required to be power of 2 */ 1204 obj->valid_hash_gnu = powerof2(nmaskwords) && 1205 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1206 } 1207 break; 1208 1209 case DT_NEEDED: 1210 if (!obj->rtld) { 1211 Needed_Entry *nep = NEW(Needed_Entry); 1212 nep->name = dynp->d_un.d_val; 1213 nep->obj = NULL; 1214 nep->next = NULL; 1215 1216 *needed_tail = nep; 1217 needed_tail = &nep->next; 1218 } 1219 break; 1220 1221 case DT_FILTER: 1222 if (!obj->rtld) { 1223 Needed_Entry *nep = NEW(Needed_Entry); 1224 nep->name = dynp->d_un.d_val; 1225 nep->obj = NULL; 1226 nep->next = NULL; 1227 1228 *needed_filtees_tail = nep; 1229 needed_filtees_tail = &nep->next; 1230 1231 if (obj->linkmap.l_refname == NULL) 1232 obj->linkmap.l_refname = (char *)dynp->d_un.d_val; 1233 } 1234 break; 1235 1236 case DT_AUXILIARY: 1237 if (!obj->rtld) { 1238 Needed_Entry *nep = NEW(Needed_Entry); 1239 nep->name = dynp->d_un.d_val; 1240 nep->obj = NULL; 1241 nep->next = NULL; 1242 1243 *needed_aux_filtees_tail = nep; 1244 needed_aux_filtees_tail = &nep->next; 1245 } 1246 break; 1247 1248 case DT_PLTGOT: 1249 obj->pltgot = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr); 1250 break; 1251 1252 case DT_TEXTREL: 1253 obj->textrel = true; 1254 break; 1255 1256 case DT_SYMBOLIC: 1257 obj->symbolic = true; 1258 break; 1259 1260 case DT_RPATH: 1261 /* 1262 * We have to wait until later to process this, because we 1263 * might not have gotten the address of the string table yet. 1264 */ 1265 *dyn_rpath = dynp; 1266 break; 1267 1268 case DT_SONAME: 1269 *dyn_soname = dynp; 1270 break; 1271 1272 case DT_RUNPATH: 1273 *dyn_runpath = dynp; 1274 break; 1275 1276 case DT_INIT: 1277 obj->init = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1278 break; 1279 1280 case DT_PREINIT_ARRAY: 1281 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1282 break; 1283 1284 case DT_PREINIT_ARRAYSZ: 1285 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1286 break; 1287 1288 case DT_INIT_ARRAY: 1289 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1290 break; 1291 1292 case DT_INIT_ARRAYSZ: 1293 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1294 break; 1295 1296 case DT_FINI: 1297 obj->fini = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1298 break; 1299 1300 case DT_FINI_ARRAY: 1301 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1302 break; 1303 1304 case DT_FINI_ARRAYSZ: 1305 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1306 break; 1307 1308 /* 1309 * Don't process DT_DEBUG on MIPS as the dynamic section 1310 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1311 */ 1312 1313 #ifndef __mips__ 1314 case DT_DEBUG: 1315 if (!early) 1316 dbg("Filling in DT_DEBUG entry"); 1317 (__DECONST(Elf_Dyn *, dynp))->d_un.d_ptr = (Elf_Addr)&r_debug; 1318 break; 1319 #endif 1320 1321 case DT_FLAGS: 1322 if (dynp->d_un.d_val & DF_ORIGIN) 1323 obj->z_origin = true; 1324 if (dynp->d_un.d_val & DF_SYMBOLIC) 1325 obj->symbolic = true; 1326 if (dynp->d_un.d_val & DF_TEXTREL) 1327 obj->textrel = true; 1328 if (dynp->d_un.d_val & DF_BIND_NOW) 1329 obj->bind_now = true; 1330 if (dynp->d_un.d_val & DF_STATIC_TLS) 1331 obj->static_tls = true; 1332 break; 1333 #ifdef __mips__ 1334 case DT_MIPS_LOCAL_GOTNO: 1335 obj->local_gotno = dynp->d_un.d_val; 1336 break; 1337 1338 case DT_MIPS_SYMTABNO: 1339 obj->symtabno = dynp->d_un.d_val; 1340 break; 1341 1342 case DT_MIPS_GOTSYM: 1343 obj->gotsym = dynp->d_un.d_val; 1344 break; 1345 1346 case DT_MIPS_RLD_MAP: 1347 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1348 break; 1349 1350 case DT_MIPS_RLD_MAP_REL: 1351 // The MIPS_RLD_MAP_REL tag stores the offset to the .rld_map 1352 // section relative to the address of the tag itself. 1353 *((Elf_Addr *)(__DECONST(char*, dynp) + dynp->d_un.d_val)) = 1354 (Elf_Addr) &r_debug; 1355 break; 1356 1357 case DT_MIPS_PLTGOT: 1358 obj->mips_pltgot = (Elf_Addr *)(obj->relocbase + 1359 dynp->d_un.d_ptr); 1360 break; 1361 1362 #endif 1363 1364 #ifdef __powerpc__ 1365 #ifdef __powerpc64__ 1366 case DT_PPC64_GLINK: 1367 obj->glink = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1368 break; 1369 #else 1370 case DT_PPC_GOT: 1371 obj->gotptr = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr); 1372 break; 1373 #endif 1374 #endif 1375 1376 case DT_FLAGS_1: 1377 if (dynp->d_un.d_val & DF_1_NOOPEN) 1378 obj->z_noopen = true; 1379 if (dynp->d_un.d_val & DF_1_ORIGIN) 1380 obj->z_origin = true; 1381 if (dynp->d_un.d_val & DF_1_GLOBAL) 1382 obj->z_global = true; 1383 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1384 obj->bind_now = true; 1385 if (dynp->d_un.d_val & DF_1_NODELETE) 1386 obj->z_nodelete = true; 1387 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1388 obj->z_loadfltr = true; 1389 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1390 obj->z_interpose = true; 1391 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1392 obj->z_nodeflib = true; 1393 if (dynp->d_un.d_val & DF_1_PIE) 1394 obj->z_pie = true; 1395 break; 1396 1397 default: 1398 if (!early) { 1399 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1400 (long)dynp->d_tag); 1401 } 1402 break; 1403 } 1404 } 1405 1406 obj->traced = false; 1407 1408 if (plttype == DT_RELA) { 1409 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1410 obj->pltrel = NULL; 1411 obj->pltrelasize = obj->pltrelsize; 1412 obj->pltrelsize = 0; 1413 } 1414 1415 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1416 if (obj->valid_hash_sysv) 1417 obj->dynsymcount = obj->nchains; 1418 else if (obj->valid_hash_gnu) { 1419 obj->dynsymcount = 0; 1420 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1421 if (obj->buckets_gnu[bkt] == 0) 1422 continue; 1423 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1424 do 1425 obj->dynsymcount++; 1426 while ((*hashval++ & 1u) == 0); 1427 } 1428 obj->dynsymcount += obj->symndx_gnu; 1429 } 1430 1431 if (obj->linkmap.l_refname != NULL) 1432 obj->linkmap.l_refname = obj->strtab + (unsigned long)obj-> 1433 linkmap.l_refname; 1434 } 1435 1436 static bool 1437 obj_resolve_origin(Obj_Entry *obj) 1438 { 1439 1440 if (obj->origin_path != NULL) 1441 return (true); 1442 obj->origin_path = xmalloc(PATH_MAX); 1443 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1); 1444 } 1445 1446 static bool 1447 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1448 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1449 { 1450 1451 if (obj->z_origin && !obj_resolve_origin(obj)) 1452 return (false); 1453 1454 if (dyn_runpath != NULL) { 1455 obj->runpath = (const char *)obj->strtab + dyn_runpath->d_un.d_val; 1456 obj->runpath = origin_subst(obj, obj->runpath); 1457 } else if (dyn_rpath != NULL) { 1458 obj->rpath = (const char *)obj->strtab + dyn_rpath->d_un.d_val; 1459 obj->rpath = origin_subst(obj, obj->rpath); 1460 } 1461 if (dyn_soname != NULL) 1462 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1463 return (true); 1464 } 1465 1466 static bool 1467 digest_dynamic(Obj_Entry *obj, int early) 1468 { 1469 const Elf_Dyn *dyn_rpath; 1470 const Elf_Dyn *dyn_soname; 1471 const Elf_Dyn *dyn_runpath; 1472 1473 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1474 return (digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath)); 1475 } 1476 1477 /* 1478 * Process a shared object's program header. This is used only for the 1479 * main program, when the kernel has already loaded the main program 1480 * into memory before calling the dynamic linker. It creates and 1481 * returns an Obj_Entry structure. 1482 */ 1483 static Obj_Entry * 1484 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1485 { 1486 Obj_Entry *obj; 1487 const Elf_Phdr *phlimit = phdr + phnum; 1488 const Elf_Phdr *ph; 1489 Elf_Addr note_start, note_end; 1490 int nsegs = 0; 1491 1492 obj = obj_new(); 1493 for (ph = phdr; ph < phlimit; ph++) { 1494 if (ph->p_type != PT_PHDR) 1495 continue; 1496 1497 obj->phdr = phdr; 1498 obj->phsize = ph->p_memsz; 1499 obj->relocbase = __DECONST(char *, phdr) - ph->p_vaddr; 1500 break; 1501 } 1502 1503 obj->stack_flags = PF_X | PF_R | PF_W; 1504 1505 for (ph = phdr; ph < phlimit; ph++) { 1506 switch (ph->p_type) { 1507 1508 case PT_INTERP: 1509 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1510 break; 1511 1512 case PT_LOAD: 1513 if (nsegs == 0) { /* First load segment */ 1514 obj->vaddrbase = trunc_page(ph->p_vaddr); 1515 obj->mapbase = obj->vaddrbase + obj->relocbase; 1516 } else { /* Last load segment */ 1517 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1518 obj->vaddrbase; 1519 } 1520 nsegs++; 1521 break; 1522 1523 case PT_DYNAMIC: 1524 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1525 break; 1526 1527 case PT_TLS: 1528 obj->tlsindex = 1; 1529 obj->tlssize = ph->p_memsz; 1530 obj->tlsalign = ph->p_align; 1531 obj->tlsinitsize = ph->p_filesz; 1532 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1533 obj->tlspoffset = ph->p_offset; 1534 break; 1535 1536 case PT_GNU_STACK: 1537 obj->stack_flags = ph->p_flags; 1538 break; 1539 1540 case PT_GNU_RELRO: 1541 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1542 obj->relro_size = round_page(ph->p_memsz); 1543 break; 1544 1545 case PT_NOTE: 1546 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1547 note_end = note_start + ph->p_filesz; 1548 digest_notes(obj, note_start, note_end); 1549 break; 1550 } 1551 } 1552 if (nsegs < 1) { 1553 _rtld_error("%s: too few PT_LOAD segments", path); 1554 return NULL; 1555 } 1556 1557 obj->entry = entry; 1558 return obj; 1559 } 1560 1561 void 1562 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1563 { 1564 const Elf_Note *note; 1565 const char *note_name; 1566 uintptr_t p; 1567 1568 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1569 note = (const Elf_Note *)((const char *)(note + 1) + 1570 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1571 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1572 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1573 note->n_descsz != sizeof(int32_t)) 1574 continue; 1575 if (note->n_type != NT_FREEBSD_ABI_TAG && 1576 note->n_type != NT_FREEBSD_FEATURE_CTL && 1577 note->n_type != NT_FREEBSD_NOINIT_TAG) 1578 continue; 1579 note_name = (const char *)(note + 1); 1580 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1581 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1582 continue; 1583 switch (note->n_type) { 1584 case NT_FREEBSD_ABI_TAG: 1585 /* FreeBSD osrel note */ 1586 p = (uintptr_t)(note + 1); 1587 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1588 obj->osrel = *(const int32_t *)(p); 1589 dbg("note osrel %d", obj->osrel); 1590 break; 1591 case NT_FREEBSD_FEATURE_CTL: 1592 /* FreeBSD ABI feature control note */ 1593 p = (uintptr_t)(note + 1); 1594 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1595 obj->fctl0 = *(const uint32_t *)(p); 1596 dbg("note fctl0 %#x", obj->fctl0); 1597 break; 1598 case NT_FREEBSD_NOINIT_TAG: 1599 /* FreeBSD 'crt does not call init' note */ 1600 obj->crt_no_init = true; 1601 dbg("note crt_no_init"); 1602 break; 1603 } 1604 } 1605 } 1606 1607 static Obj_Entry * 1608 dlcheck(void *handle) 1609 { 1610 Obj_Entry *obj; 1611 1612 TAILQ_FOREACH(obj, &obj_list, next) { 1613 if (obj == (Obj_Entry *) handle) 1614 break; 1615 } 1616 1617 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1618 _rtld_error("Invalid shared object handle %p", handle); 1619 return NULL; 1620 } 1621 return obj; 1622 } 1623 1624 /* 1625 * If the given object is already in the donelist, return true. Otherwise 1626 * add the object to the list and return false. 1627 */ 1628 static bool 1629 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1630 { 1631 unsigned int i; 1632 1633 for (i = 0; i < dlp->num_used; i++) 1634 if (dlp->objs[i] == obj) 1635 return true; 1636 /* 1637 * Our donelist allocation should always be sufficient. But if 1638 * our threads locking isn't working properly, more shared objects 1639 * could have been loaded since we allocated the list. That should 1640 * never happen, but we'll handle it properly just in case it does. 1641 */ 1642 if (dlp->num_used < dlp->num_alloc) 1643 dlp->objs[dlp->num_used++] = obj; 1644 return false; 1645 } 1646 1647 /* 1648 * Hash function for symbol table lookup. Don't even think about changing 1649 * this. It is specified by the System V ABI. 1650 */ 1651 unsigned long 1652 elf_hash(const char *name) 1653 { 1654 const unsigned char *p = (const unsigned char *) name; 1655 unsigned long h = 0; 1656 unsigned long g; 1657 1658 while (*p != '\0') { 1659 h = (h << 4) + *p++; 1660 if ((g = h & 0xf0000000) != 0) 1661 h ^= g >> 24; 1662 h &= ~g; 1663 } 1664 return h; 1665 } 1666 1667 /* 1668 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1669 * unsigned in case it's implemented with a wider type. 1670 */ 1671 static uint32_t 1672 gnu_hash(const char *s) 1673 { 1674 uint32_t h; 1675 unsigned char c; 1676 1677 h = 5381; 1678 for (c = *s; c != '\0'; c = *++s) 1679 h = h * 33 + c; 1680 return (h & 0xffffffff); 1681 } 1682 1683 1684 /* 1685 * Find the library with the given name, and return its full pathname. 1686 * The returned string is dynamically allocated. Generates an error 1687 * message and returns NULL if the library cannot be found. 1688 * 1689 * If the second argument is non-NULL, then it refers to an already- 1690 * loaded shared object, whose library search path will be searched. 1691 * 1692 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1693 * descriptor (which is close-on-exec) will be passed out via the third 1694 * argument. 1695 * 1696 * The search order is: 1697 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1698 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1699 * LD_LIBRARY_PATH 1700 * DT_RUNPATH in the referencing file 1701 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1702 * from list) 1703 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1704 * 1705 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1706 */ 1707 static char * 1708 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1709 { 1710 char *pathname, *refobj_path; 1711 const char *name; 1712 bool nodeflib, objgiven; 1713 1714 objgiven = refobj != NULL; 1715 1716 if (libmap_disable || !objgiven || 1717 (name = lm_find(refobj->path, xname)) == NULL) 1718 name = xname; 1719 1720 if (strchr(name, '/') != NULL) { /* Hard coded pathname */ 1721 if (name[0] != '/' && !trust) { 1722 _rtld_error("Absolute pathname required " 1723 "for shared object \"%s\"", name); 1724 return (NULL); 1725 } 1726 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1727 __DECONST(char *, name))); 1728 } 1729 1730 dbg(" Searching for \"%s\"", name); 1731 refobj_path = objgiven ? refobj->path : NULL; 1732 1733 /* 1734 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1735 * back to pre-conforming behaviour if user requested so with 1736 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1737 * nodeflib. 1738 */ 1739 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1740 pathname = search_library_path(name, ld_library_path, 1741 refobj_path, fdp); 1742 if (pathname != NULL) 1743 return (pathname); 1744 if (refobj != NULL) { 1745 pathname = search_library_path(name, refobj->rpath, 1746 refobj_path, fdp); 1747 if (pathname != NULL) 1748 return (pathname); 1749 } 1750 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1751 if (pathname != NULL) 1752 return (pathname); 1753 pathname = search_library_path(name, gethints(false), 1754 refobj_path, fdp); 1755 if (pathname != NULL) 1756 return (pathname); 1757 pathname = search_library_path(name, ld_standard_library_path, 1758 refobj_path, fdp); 1759 if (pathname != NULL) 1760 return (pathname); 1761 } else { 1762 nodeflib = objgiven ? refobj->z_nodeflib : false; 1763 if (objgiven) { 1764 pathname = search_library_path(name, refobj->rpath, 1765 refobj->path, fdp); 1766 if (pathname != NULL) 1767 return (pathname); 1768 } 1769 if (objgiven && refobj->runpath == NULL && refobj != obj_main) { 1770 pathname = search_library_path(name, obj_main->rpath, 1771 refobj_path, fdp); 1772 if (pathname != NULL) 1773 return (pathname); 1774 } 1775 pathname = search_library_path(name, ld_library_path, 1776 refobj_path, fdp); 1777 if (pathname != NULL) 1778 return (pathname); 1779 if (objgiven) { 1780 pathname = search_library_path(name, refobj->runpath, 1781 refobj_path, fdp); 1782 if (pathname != NULL) 1783 return (pathname); 1784 } 1785 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1786 if (pathname != NULL) 1787 return (pathname); 1788 pathname = search_library_path(name, gethints(nodeflib), 1789 refobj_path, fdp); 1790 if (pathname != NULL) 1791 return (pathname); 1792 if (objgiven && !nodeflib) { 1793 pathname = search_library_path(name, 1794 ld_standard_library_path, refobj_path, fdp); 1795 if (pathname != NULL) 1796 return (pathname); 1797 } 1798 } 1799 1800 if (objgiven && refobj->path != NULL) { 1801 _rtld_error("Shared object \"%s\" not found, " 1802 "required by \"%s\"", name, basename(refobj->path)); 1803 } else { 1804 _rtld_error("Shared object \"%s\" not found", name); 1805 } 1806 return (NULL); 1807 } 1808 1809 /* 1810 * Given a symbol number in a referencing object, find the corresponding 1811 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1812 * no definition was found. Returns a pointer to the Obj_Entry of the 1813 * defining object via the reference parameter DEFOBJ_OUT. 1814 */ 1815 const Elf_Sym * 1816 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1817 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1818 RtldLockState *lockstate) 1819 { 1820 const Elf_Sym *ref; 1821 const Elf_Sym *def; 1822 const Obj_Entry *defobj; 1823 const Ver_Entry *ve; 1824 SymLook req; 1825 const char *name; 1826 int res; 1827 1828 /* 1829 * If we have already found this symbol, get the information from 1830 * the cache. 1831 */ 1832 if (symnum >= refobj->dynsymcount) 1833 return NULL; /* Bad object */ 1834 if (cache != NULL && cache[symnum].sym != NULL) { 1835 *defobj_out = cache[symnum].obj; 1836 return cache[symnum].sym; 1837 } 1838 1839 ref = refobj->symtab + symnum; 1840 name = refobj->strtab + ref->st_name; 1841 def = NULL; 1842 defobj = NULL; 1843 ve = NULL; 1844 1845 /* 1846 * We don't have to do a full scale lookup if the symbol is local. 1847 * We know it will bind to the instance in this load module; to 1848 * which we already have a pointer (ie ref). By not doing a lookup, 1849 * we not only improve performance, but it also avoids unresolvable 1850 * symbols when local symbols are not in the hash table. This has 1851 * been seen with the ia64 toolchain. 1852 */ 1853 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1854 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1855 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1856 symnum); 1857 } 1858 symlook_init(&req, name); 1859 req.flags = flags; 1860 ve = req.ventry = fetch_ventry(refobj, symnum); 1861 req.lockstate = lockstate; 1862 res = symlook_default(&req, refobj); 1863 if (res == 0) { 1864 def = req.sym_out; 1865 defobj = req.defobj_out; 1866 } 1867 } else { 1868 def = ref; 1869 defobj = refobj; 1870 } 1871 1872 /* 1873 * If we found no definition and the reference is weak, treat the 1874 * symbol as having the value zero. 1875 */ 1876 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1877 def = &sym_zero; 1878 defobj = obj_main; 1879 } 1880 1881 if (def != NULL) { 1882 *defobj_out = defobj; 1883 /* Record the information in the cache to avoid subsequent lookups. */ 1884 if (cache != NULL) { 1885 cache[symnum].sym = def; 1886 cache[symnum].obj = defobj; 1887 } 1888 } else { 1889 if (refobj != &obj_rtld) 1890 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name, 1891 ve != NULL ? "@" : "", ve != NULL ? ve->name : ""); 1892 } 1893 return def; 1894 } 1895 1896 /* 1897 * Return the search path from the ldconfig hints file, reading it if 1898 * necessary. If nostdlib is true, then the default search paths are 1899 * not added to result. 1900 * 1901 * Returns NULL if there are problems with the hints file, 1902 * or if the search path there is empty. 1903 */ 1904 static const char * 1905 gethints(bool nostdlib) 1906 { 1907 static char *filtered_path; 1908 static const char *hints; 1909 static struct elfhints_hdr hdr; 1910 struct fill_search_info_args sargs, hargs; 1911 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1912 struct dl_serpath *SLPpath, *hintpath; 1913 char *p; 1914 struct stat hint_stat; 1915 unsigned int SLPndx, hintndx, fndx, fcount; 1916 int fd; 1917 size_t flen; 1918 uint32_t dl; 1919 bool skip; 1920 1921 /* First call, read the hints file */ 1922 if (hints == NULL) { 1923 /* Keep from trying again in case the hints file is bad. */ 1924 hints = ""; 1925 1926 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1927 return (NULL); 1928 1929 /* 1930 * Check of hdr.dirlistlen value against type limit 1931 * intends to pacify static analyzers. Further 1932 * paranoia leads to checks that dirlist is fully 1933 * contained in the file range. 1934 */ 1935 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1936 hdr.magic != ELFHINTS_MAGIC || 1937 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 || 1938 fstat(fd, &hint_stat) == -1) { 1939 cleanup1: 1940 close(fd); 1941 hdr.dirlistlen = 0; 1942 return (NULL); 1943 } 1944 dl = hdr.strtab; 1945 if (dl + hdr.dirlist < dl) 1946 goto cleanup1; 1947 dl += hdr.dirlist; 1948 if (dl + hdr.dirlistlen < dl) 1949 goto cleanup1; 1950 dl += hdr.dirlistlen; 1951 if (dl > hint_stat.st_size) 1952 goto cleanup1; 1953 p = xmalloc(hdr.dirlistlen + 1); 1954 if (pread(fd, p, hdr.dirlistlen + 1, 1955 hdr.strtab + hdr.dirlist) != (ssize_t)hdr.dirlistlen + 1 || 1956 p[hdr.dirlistlen] != '\0') { 1957 free(p); 1958 goto cleanup1; 1959 } 1960 hints = p; 1961 close(fd); 1962 } 1963 1964 /* 1965 * If caller agreed to receive list which includes the default 1966 * paths, we are done. Otherwise, if we still did not 1967 * calculated filtered result, do it now. 1968 */ 1969 if (!nostdlib) 1970 return (hints[0] != '\0' ? hints : NULL); 1971 if (filtered_path != NULL) 1972 goto filt_ret; 1973 1974 /* 1975 * Obtain the list of all configured search paths, and the 1976 * list of the default paths. 1977 * 1978 * First estimate the size of the results. 1979 */ 1980 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1981 smeta.dls_cnt = 0; 1982 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1983 hmeta.dls_cnt = 0; 1984 1985 sargs.request = RTLD_DI_SERINFOSIZE; 1986 sargs.serinfo = &smeta; 1987 hargs.request = RTLD_DI_SERINFOSIZE; 1988 hargs.serinfo = &hmeta; 1989 1990 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 1991 &sargs); 1992 path_enumerate(hints, fill_search_info, NULL, &hargs); 1993 1994 SLPinfo = xmalloc(smeta.dls_size); 1995 hintinfo = xmalloc(hmeta.dls_size); 1996 1997 /* 1998 * Next fetch both sets of paths. 1999 */ 2000 sargs.request = RTLD_DI_SERINFO; 2001 sargs.serinfo = SLPinfo; 2002 sargs.serpath = &SLPinfo->dls_serpath[0]; 2003 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 2004 2005 hargs.request = RTLD_DI_SERINFO; 2006 hargs.serinfo = hintinfo; 2007 hargs.serpath = &hintinfo->dls_serpath[0]; 2008 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 2009 2010 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 2011 &sargs); 2012 path_enumerate(hints, fill_search_info, NULL, &hargs); 2013 2014 /* 2015 * Now calculate the difference between two sets, by excluding 2016 * standard paths from the full set. 2017 */ 2018 fndx = 0; 2019 fcount = 0; 2020 filtered_path = xmalloc(hdr.dirlistlen + 1); 2021 hintpath = &hintinfo->dls_serpath[0]; 2022 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 2023 skip = false; 2024 SLPpath = &SLPinfo->dls_serpath[0]; 2025 /* 2026 * Check each standard path against current. 2027 */ 2028 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 2029 /* matched, skip the path */ 2030 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 2031 skip = true; 2032 break; 2033 } 2034 } 2035 if (skip) 2036 continue; 2037 /* 2038 * Not matched against any standard path, add the path 2039 * to result. Separate consequtive paths with ':'. 2040 */ 2041 if (fcount > 0) { 2042 filtered_path[fndx] = ':'; 2043 fndx++; 2044 } 2045 fcount++; 2046 flen = strlen(hintpath->dls_name); 2047 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 2048 fndx += flen; 2049 } 2050 filtered_path[fndx] = '\0'; 2051 2052 free(SLPinfo); 2053 free(hintinfo); 2054 2055 filt_ret: 2056 return (filtered_path[0] != '\0' ? filtered_path : NULL); 2057 } 2058 2059 static void 2060 init_dag(Obj_Entry *root) 2061 { 2062 const Needed_Entry *needed; 2063 const Objlist_Entry *elm; 2064 DoneList donelist; 2065 2066 if (root->dag_inited) 2067 return; 2068 donelist_init(&donelist); 2069 2070 /* Root object belongs to own DAG. */ 2071 objlist_push_tail(&root->dldags, root); 2072 objlist_push_tail(&root->dagmembers, root); 2073 donelist_check(&donelist, root); 2074 2075 /* 2076 * Add dependencies of root object to DAG in breadth order 2077 * by exploiting the fact that each new object get added 2078 * to the tail of the dagmembers list. 2079 */ 2080 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2081 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 2082 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 2083 continue; 2084 objlist_push_tail(&needed->obj->dldags, root); 2085 objlist_push_tail(&root->dagmembers, needed->obj); 2086 } 2087 } 2088 root->dag_inited = true; 2089 } 2090 2091 static void 2092 init_marker(Obj_Entry *marker) 2093 { 2094 2095 bzero(marker, sizeof(*marker)); 2096 marker->marker = true; 2097 } 2098 2099 Obj_Entry * 2100 globallist_curr(const Obj_Entry *obj) 2101 { 2102 2103 for (;;) { 2104 if (obj == NULL) 2105 return (NULL); 2106 if (!obj->marker) 2107 return (__DECONST(Obj_Entry *, obj)); 2108 obj = TAILQ_PREV(obj, obj_entry_q, next); 2109 } 2110 } 2111 2112 Obj_Entry * 2113 globallist_next(const Obj_Entry *obj) 2114 { 2115 2116 for (;;) { 2117 obj = TAILQ_NEXT(obj, next); 2118 if (obj == NULL) 2119 return (NULL); 2120 if (!obj->marker) 2121 return (__DECONST(Obj_Entry *, obj)); 2122 } 2123 } 2124 2125 /* Prevent the object from being unmapped while the bind lock is dropped. */ 2126 static void 2127 hold_object(Obj_Entry *obj) 2128 { 2129 2130 obj->holdcount++; 2131 } 2132 2133 static void 2134 unhold_object(Obj_Entry *obj) 2135 { 2136 2137 assert(obj->holdcount > 0); 2138 if (--obj->holdcount == 0 && obj->unholdfree) 2139 release_object(obj); 2140 } 2141 2142 static void 2143 process_z(Obj_Entry *root) 2144 { 2145 const Objlist_Entry *elm; 2146 Obj_Entry *obj; 2147 2148 /* 2149 * Walk over object DAG and process every dependent object 2150 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 2151 * to grow their own DAG. 2152 * 2153 * For DF_1_GLOBAL, DAG is required for symbol lookups in 2154 * symlook_global() to work. 2155 * 2156 * For DF_1_NODELETE, the DAG should have its reference upped. 2157 */ 2158 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2159 obj = elm->obj; 2160 if (obj == NULL) 2161 continue; 2162 if (obj->z_nodelete && !obj->ref_nodel) { 2163 dbg("obj %s -z nodelete", obj->path); 2164 init_dag(obj); 2165 ref_dag(obj); 2166 obj->ref_nodel = true; 2167 } 2168 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 2169 dbg("obj %s -z global", obj->path); 2170 objlist_push_tail(&list_global, obj); 2171 init_dag(obj); 2172 } 2173 } 2174 } 2175 2176 static void 2177 parse_rtld_phdr(Obj_Entry *obj) 2178 { 2179 const Elf_Phdr *ph; 2180 Elf_Addr note_start, note_end; 2181 2182 obj->stack_flags = PF_X | PF_R | PF_W; 2183 for (ph = obj->phdr; (const char *)ph < (const char *)obj->phdr + 2184 obj->phsize; ph++) { 2185 switch (ph->p_type) { 2186 case PT_GNU_STACK: 2187 obj->stack_flags = ph->p_flags; 2188 break; 2189 case PT_GNU_RELRO: 2190 obj->relro_page = obj->relocbase + 2191 trunc_page(ph->p_vaddr); 2192 obj->relro_size = round_page(ph->p_memsz); 2193 break; 2194 case PT_NOTE: 2195 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 2196 note_end = note_start + ph->p_filesz; 2197 digest_notes(obj, note_start, note_end); 2198 break; 2199 } 2200 } 2201 } 2202 2203 /* 2204 * Initialize the dynamic linker. The argument is the address at which 2205 * the dynamic linker has been mapped into memory. The primary task of 2206 * this function is to relocate the dynamic linker. 2207 */ 2208 static void 2209 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 2210 { 2211 Obj_Entry objtmp; /* Temporary rtld object */ 2212 const Elf_Ehdr *ehdr; 2213 const Elf_Dyn *dyn_rpath; 2214 const Elf_Dyn *dyn_soname; 2215 const Elf_Dyn *dyn_runpath; 2216 2217 #ifdef RTLD_INIT_PAGESIZES_EARLY 2218 /* The page size is required by the dynamic memory allocator. */ 2219 init_pagesizes(aux_info); 2220 #endif 2221 2222 /* 2223 * Conjure up an Obj_Entry structure for the dynamic linker. 2224 * 2225 * The "path" member can't be initialized yet because string constants 2226 * cannot yet be accessed. Below we will set it correctly. 2227 */ 2228 memset(&objtmp, 0, sizeof(objtmp)); 2229 objtmp.path = NULL; 2230 objtmp.rtld = true; 2231 objtmp.mapbase = mapbase; 2232 #ifdef PIC 2233 objtmp.relocbase = mapbase; 2234 #endif 2235 2236 objtmp.dynamic = rtld_dynamic(&objtmp); 2237 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 2238 assert(objtmp.needed == NULL); 2239 #if !defined(__mips__) 2240 /* MIPS has a bogus DT_TEXTREL. */ 2241 assert(!objtmp.textrel); 2242 #endif 2243 /* 2244 * Temporarily put the dynamic linker entry into the object list, so 2245 * that symbols can be found. 2246 */ 2247 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 2248 2249 ehdr = (Elf_Ehdr *)mapbase; 2250 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 2251 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 2252 2253 /* Initialize the object list. */ 2254 TAILQ_INIT(&obj_list); 2255 2256 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 2257 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 2258 2259 #ifndef RTLD_INIT_PAGESIZES_EARLY 2260 /* The page size is required by the dynamic memory allocator. */ 2261 init_pagesizes(aux_info); 2262 #endif 2263 2264 if (aux_info[AT_OSRELDATE] != NULL) 2265 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 2266 2267 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 2268 2269 /* Replace the path with a dynamically allocated copy. */ 2270 obj_rtld.path = xstrdup(ld_path_rtld); 2271 2272 parse_rtld_phdr(&obj_rtld); 2273 obj_enforce_relro(&obj_rtld); 2274 2275 r_debug.r_version = R_DEBUG_VERSION; 2276 r_debug.r_brk = r_debug_state; 2277 r_debug.r_state = RT_CONSISTENT; 2278 r_debug.r_ldbase = obj_rtld.relocbase; 2279 } 2280 2281 /* 2282 * Retrieve the array of supported page sizes. The kernel provides the page 2283 * sizes in increasing order. 2284 */ 2285 static void 2286 init_pagesizes(Elf_Auxinfo **aux_info) 2287 { 2288 static size_t psa[MAXPAGESIZES]; 2289 int mib[2]; 2290 size_t len, size; 2291 2292 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 2293 NULL) { 2294 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 2295 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 2296 } else { 2297 len = 2; 2298 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 2299 size = sizeof(psa); 2300 else { 2301 /* As a fallback, retrieve the base page size. */ 2302 size = sizeof(psa[0]); 2303 if (aux_info[AT_PAGESZ] != NULL) { 2304 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 2305 goto psa_filled; 2306 } else { 2307 mib[0] = CTL_HW; 2308 mib[1] = HW_PAGESIZE; 2309 len = 2; 2310 } 2311 } 2312 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 2313 _rtld_error("sysctl for hw.pagesize(s) failed"); 2314 rtld_die(); 2315 } 2316 psa_filled: 2317 pagesizes = psa; 2318 } 2319 npagesizes = size / sizeof(pagesizes[0]); 2320 /* Discard any invalid entries at the end of the array. */ 2321 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 2322 npagesizes--; 2323 } 2324 2325 /* 2326 * Add the init functions from a needed object list (and its recursive 2327 * needed objects) to "list". This is not used directly; it is a helper 2328 * function for initlist_add_objects(). The write lock must be held 2329 * when this function is called. 2330 */ 2331 static void 2332 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 2333 { 2334 /* Recursively process the successor needed objects. */ 2335 if (needed->next != NULL) 2336 initlist_add_neededs(needed->next, list); 2337 2338 /* Process the current needed object. */ 2339 if (needed->obj != NULL) 2340 initlist_add_objects(needed->obj, needed->obj, list); 2341 } 2342 2343 /* 2344 * Scan all of the DAGs rooted in the range of objects from "obj" to 2345 * "tail" and add their init functions to "list". This recurses over 2346 * the DAGs and ensure the proper init ordering such that each object's 2347 * needed libraries are initialized before the object itself. At the 2348 * same time, this function adds the objects to the global finalization 2349 * list "list_fini" in the opposite order. The write lock must be 2350 * held when this function is called. 2351 */ 2352 static void 2353 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2354 { 2355 Obj_Entry *nobj; 2356 2357 if (obj->init_scanned || obj->init_done) 2358 return; 2359 obj->init_scanned = true; 2360 2361 /* Recursively process the successor objects. */ 2362 nobj = globallist_next(obj); 2363 if (nobj != NULL && obj != tail) 2364 initlist_add_objects(nobj, tail, list); 2365 2366 /* Recursively process the needed objects. */ 2367 if (obj->needed != NULL) 2368 initlist_add_neededs(obj->needed, list); 2369 if (obj->needed_filtees != NULL) 2370 initlist_add_neededs(obj->needed_filtees, list); 2371 if (obj->needed_aux_filtees != NULL) 2372 initlist_add_neededs(obj->needed_aux_filtees, list); 2373 2374 /* Add the object to the init list. */ 2375 objlist_push_tail(list, obj); 2376 2377 /* Add the object to the global fini list in the reverse order. */ 2378 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2379 && !obj->on_fini_list) { 2380 objlist_push_head(&list_fini, obj); 2381 obj->on_fini_list = true; 2382 } 2383 } 2384 2385 #ifndef FPTR_TARGET 2386 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 2387 #endif 2388 2389 static void 2390 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate) 2391 { 2392 Needed_Entry *needed, *needed1; 2393 2394 for (needed = n; needed != NULL; needed = needed->next) { 2395 if (needed->obj != NULL) { 2396 dlclose_locked(needed->obj, lockstate); 2397 needed->obj = NULL; 2398 } 2399 } 2400 for (needed = n; needed != NULL; needed = needed1) { 2401 needed1 = needed->next; 2402 free(needed); 2403 } 2404 } 2405 2406 static void 2407 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate) 2408 { 2409 2410 free_needed_filtees(obj->needed_filtees, lockstate); 2411 obj->needed_filtees = NULL; 2412 free_needed_filtees(obj->needed_aux_filtees, lockstate); 2413 obj->needed_aux_filtees = NULL; 2414 obj->filtees_loaded = false; 2415 } 2416 2417 static void 2418 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2419 RtldLockState *lockstate) 2420 { 2421 2422 for (; needed != NULL; needed = needed->next) { 2423 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2424 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2425 RTLD_LOCAL, lockstate); 2426 } 2427 } 2428 2429 static void 2430 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2431 { 2432 2433 lock_restart_for_upgrade(lockstate); 2434 if (!obj->filtees_loaded) { 2435 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2436 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2437 obj->filtees_loaded = true; 2438 } 2439 } 2440 2441 static int 2442 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2443 { 2444 Obj_Entry *obj1; 2445 2446 for (; needed != NULL; needed = needed->next) { 2447 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2448 flags & ~RTLD_LO_NOLOAD); 2449 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2450 return (-1); 2451 } 2452 return (0); 2453 } 2454 2455 /* 2456 * Given a shared object, traverse its list of needed objects, and load 2457 * each of them. Returns 0 on success. Generates an error message and 2458 * returns -1 on failure. 2459 */ 2460 static int 2461 load_needed_objects(Obj_Entry *first, int flags) 2462 { 2463 Obj_Entry *obj; 2464 2465 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2466 if (obj->marker) 2467 continue; 2468 if (process_needed(obj, obj->needed, flags) == -1) 2469 return (-1); 2470 } 2471 return (0); 2472 } 2473 2474 static int 2475 load_preload_objects(void) 2476 { 2477 char *p = ld_preload; 2478 Obj_Entry *obj; 2479 static const char delim[] = " \t:;"; 2480 2481 if (p == NULL) 2482 return 0; 2483 2484 p += strspn(p, delim); 2485 while (*p != '\0') { 2486 size_t len = strcspn(p, delim); 2487 char savech; 2488 2489 savech = p[len]; 2490 p[len] = '\0'; 2491 obj = load_object(p, -1, NULL, 0); 2492 if (obj == NULL) 2493 return -1; /* XXX - cleanup */ 2494 obj->z_interpose = true; 2495 p[len] = savech; 2496 p += len; 2497 p += strspn(p, delim); 2498 } 2499 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2500 return 0; 2501 } 2502 2503 static const char * 2504 printable_path(const char *path) 2505 { 2506 2507 return (path == NULL ? "<unknown>" : path); 2508 } 2509 2510 /* 2511 * Load a shared object into memory, if it is not already loaded. The 2512 * object may be specified by name or by user-supplied file descriptor 2513 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2514 * duplicate is. 2515 * 2516 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2517 * on failure. 2518 */ 2519 static Obj_Entry * 2520 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2521 { 2522 Obj_Entry *obj; 2523 int fd; 2524 struct stat sb; 2525 char *path; 2526 2527 fd = -1; 2528 if (name != NULL) { 2529 TAILQ_FOREACH(obj, &obj_list, next) { 2530 if (obj->marker || obj->doomed) 2531 continue; 2532 if (object_match_name(obj, name)) 2533 return (obj); 2534 } 2535 2536 path = find_library(name, refobj, &fd); 2537 if (path == NULL) 2538 return (NULL); 2539 } else 2540 path = NULL; 2541 2542 if (fd >= 0) { 2543 /* 2544 * search_library_pathfds() opens a fresh file descriptor for the 2545 * library, so there is no need to dup(). 2546 */ 2547 } else if (fd_u == -1) { 2548 /* 2549 * If we didn't find a match by pathname, or the name is not 2550 * supplied, open the file and check again by device and inode. 2551 * This avoids false mismatches caused by multiple links or ".." 2552 * in pathnames. 2553 * 2554 * To avoid a race, we open the file and use fstat() rather than 2555 * using stat(). 2556 */ 2557 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { 2558 _rtld_error("Cannot open \"%s\"", path); 2559 free(path); 2560 return (NULL); 2561 } 2562 } else { 2563 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2564 if (fd == -1) { 2565 _rtld_error("Cannot dup fd"); 2566 free(path); 2567 return (NULL); 2568 } 2569 } 2570 if (fstat(fd, &sb) == -1) { 2571 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2572 close(fd); 2573 free(path); 2574 return NULL; 2575 } 2576 TAILQ_FOREACH(obj, &obj_list, next) { 2577 if (obj->marker || obj->doomed) 2578 continue; 2579 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2580 break; 2581 } 2582 if (obj != NULL && name != NULL) { 2583 object_add_name(obj, name); 2584 free(path); 2585 close(fd); 2586 return obj; 2587 } 2588 if (flags & RTLD_LO_NOLOAD) { 2589 free(path); 2590 close(fd); 2591 return (NULL); 2592 } 2593 2594 /* First use of this object, so we must map it in */ 2595 obj = do_load_object(fd, name, path, &sb, flags); 2596 if (obj == NULL) 2597 free(path); 2598 close(fd); 2599 2600 return obj; 2601 } 2602 2603 static Obj_Entry * 2604 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2605 int flags) 2606 { 2607 Obj_Entry *obj; 2608 struct statfs fs; 2609 2610 /* 2611 * but first, make sure that environment variables haven't been 2612 * used to circumvent the noexec flag on a filesystem. 2613 */ 2614 if (dangerous_ld_env) { 2615 if (fstatfs(fd, &fs) != 0) { 2616 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2617 return NULL; 2618 } 2619 if (fs.f_flags & MNT_NOEXEC) { 2620 _rtld_error("Cannot execute objects on %s", fs.f_mntonname); 2621 return NULL; 2622 } 2623 } 2624 dbg("loading \"%s\"", printable_path(path)); 2625 obj = map_object(fd, printable_path(path), sbp); 2626 if (obj == NULL) 2627 return NULL; 2628 2629 /* 2630 * If DT_SONAME is present in the object, digest_dynamic2 already 2631 * added it to the object names. 2632 */ 2633 if (name != NULL) 2634 object_add_name(obj, name); 2635 obj->path = path; 2636 if (!digest_dynamic(obj, 0)) 2637 goto errp; 2638 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2639 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2640 if (obj->z_pie && (flags & RTLD_LO_TRACE) == 0) { 2641 dbg("refusing to load PIE executable \"%s\"", obj->path); 2642 _rtld_error("Cannot load PIE binary %s as DSO", obj->path); 2643 goto errp; 2644 } 2645 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2646 RTLD_LO_DLOPEN) { 2647 dbg("refusing to load non-loadable \"%s\"", obj->path); 2648 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2649 goto errp; 2650 } 2651 2652 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2653 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2654 obj_count++; 2655 obj_loads++; 2656 linkmap_add(obj); /* for GDB & dlinfo() */ 2657 max_stack_flags |= obj->stack_flags; 2658 2659 dbg(" %p .. %p: %s", obj->mapbase, 2660 obj->mapbase + obj->mapsize - 1, obj->path); 2661 if (obj->textrel) 2662 dbg(" WARNING: %s has impure text", obj->path); 2663 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2664 obj->path); 2665 2666 return (obj); 2667 2668 errp: 2669 munmap(obj->mapbase, obj->mapsize); 2670 obj_free(obj); 2671 return (NULL); 2672 } 2673 2674 static Obj_Entry * 2675 obj_from_addr(const void *addr) 2676 { 2677 Obj_Entry *obj; 2678 2679 TAILQ_FOREACH(obj, &obj_list, next) { 2680 if (obj->marker) 2681 continue; 2682 if (addr < (void *) obj->mapbase) 2683 continue; 2684 if (addr < (void *)(obj->mapbase + obj->mapsize)) 2685 return obj; 2686 } 2687 return NULL; 2688 } 2689 2690 static void 2691 preinit_main(void) 2692 { 2693 Elf_Addr *preinit_addr; 2694 int index; 2695 2696 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2697 if (preinit_addr == NULL) 2698 return; 2699 2700 for (index = 0; index < obj_main->preinit_array_num; index++) { 2701 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2702 dbg("calling preinit function for %s at %p", obj_main->path, 2703 (void *)preinit_addr[index]); 2704 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2705 0, 0, obj_main->path); 2706 call_init_pointer(obj_main, preinit_addr[index]); 2707 } 2708 } 2709 } 2710 2711 /* 2712 * Call the finalization functions for each of the objects in "list" 2713 * belonging to the DAG of "root" and referenced once. If NULL "root" 2714 * is specified, every finalization function will be called regardless 2715 * of the reference count and the list elements won't be freed. All of 2716 * the objects are expected to have non-NULL fini functions. 2717 */ 2718 static void 2719 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2720 { 2721 Objlist_Entry *elm; 2722 char *saved_msg; 2723 Elf_Addr *fini_addr; 2724 int index; 2725 2726 assert(root == NULL || root->refcount == 1); 2727 2728 if (root != NULL) 2729 root->doomed = true; 2730 2731 /* 2732 * Preserve the current error message since a fini function might 2733 * call into the dynamic linker and overwrite it. 2734 */ 2735 saved_msg = errmsg_save(); 2736 do { 2737 STAILQ_FOREACH(elm, list, link) { 2738 if (root != NULL && (elm->obj->refcount != 1 || 2739 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2740 continue; 2741 /* Remove object from fini list to prevent recursive invocation. */ 2742 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2743 /* Ensure that new references cannot be acquired. */ 2744 elm->obj->doomed = true; 2745 2746 hold_object(elm->obj); 2747 lock_release(rtld_bind_lock, lockstate); 2748 /* 2749 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2750 * When this happens, DT_FINI_ARRAY is processed first. 2751 */ 2752 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2753 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2754 for (index = elm->obj->fini_array_num - 1; index >= 0; 2755 index--) { 2756 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2757 dbg("calling fini function for %s at %p", 2758 elm->obj->path, (void *)fini_addr[index]); 2759 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2760 (void *)fini_addr[index], 0, 0, elm->obj->path); 2761 call_initfini_pointer(elm->obj, fini_addr[index]); 2762 } 2763 } 2764 } 2765 if (elm->obj->fini != (Elf_Addr)NULL) { 2766 dbg("calling fini function for %s at %p", elm->obj->path, 2767 (void *)elm->obj->fini); 2768 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2769 0, 0, elm->obj->path); 2770 call_initfini_pointer(elm->obj, elm->obj->fini); 2771 } 2772 wlock_acquire(rtld_bind_lock, lockstate); 2773 unhold_object(elm->obj); 2774 /* No need to free anything if process is going down. */ 2775 if (root != NULL) 2776 free(elm); 2777 /* 2778 * We must restart the list traversal after every fini call 2779 * because a dlclose() call from the fini function or from 2780 * another thread might have modified the reference counts. 2781 */ 2782 break; 2783 } 2784 } while (elm != NULL); 2785 errmsg_restore(saved_msg); 2786 } 2787 2788 /* 2789 * Call the initialization functions for each of the objects in 2790 * "list". All of the objects are expected to have non-NULL init 2791 * functions. 2792 */ 2793 static void 2794 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2795 { 2796 Objlist_Entry *elm; 2797 Obj_Entry *obj; 2798 char *saved_msg; 2799 Elf_Addr *init_addr; 2800 void (*reg)(void (*)(void)); 2801 int index; 2802 2803 /* 2804 * Clean init_scanned flag so that objects can be rechecked and 2805 * possibly initialized earlier if any of vectors called below 2806 * cause the change by using dlopen. 2807 */ 2808 TAILQ_FOREACH(obj, &obj_list, next) { 2809 if (obj->marker) 2810 continue; 2811 obj->init_scanned = false; 2812 } 2813 2814 /* 2815 * Preserve the current error message since an init function might 2816 * call into the dynamic linker and overwrite it. 2817 */ 2818 saved_msg = errmsg_save(); 2819 STAILQ_FOREACH(elm, list, link) { 2820 if (elm->obj->init_done) /* Initialized early. */ 2821 continue; 2822 /* 2823 * Race: other thread might try to use this object before current 2824 * one completes the initialization. Not much can be done here 2825 * without better locking. 2826 */ 2827 elm->obj->init_done = true; 2828 hold_object(elm->obj); 2829 reg = NULL; 2830 if (elm->obj == obj_main && obj_main->crt_no_init) { 2831 reg = (void (*)(void (*)(void)))get_program_var_addr( 2832 "__libc_atexit", lockstate); 2833 } 2834 lock_release(rtld_bind_lock, lockstate); 2835 if (reg != NULL) { 2836 reg(rtld_exit); 2837 rtld_exit_ptr = rtld_nop_exit; 2838 } 2839 2840 /* 2841 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2842 * When this happens, DT_INIT is processed first. 2843 */ 2844 if (elm->obj->init != (Elf_Addr)NULL) { 2845 dbg("calling init function for %s at %p", elm->obj->path, 2846 (void *)elm->obj->init); 2847 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2848 0, 0, elm->obj->path); 2849 call_init_pointer(elm->obj, elm->obj->init); 2850 } 2851 init_addr = (Elf_Addr *)elm->obj->init_array; 2852 if (init_addr != NULL) { 2853 for (index = 0; index < elm->obj->init_array_num; index++) { 2854 if (init_addr[index] != 0 && init_addr[index] != 1) { 2855 dbg("calling init function for %s at %p", elm->obj->path, 2856 (void *)init_addr[index]); 2857 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2858 (void *)init_addr[index], 0, 0, elm->obj->path); 2859 call_init_pointer(elm->obj, init_addr[index]); 2860 } 2861 } 2862 } 2863 wlock_acquire(rtld_bind_lock, lockstate); 2864 unhold_object(elm->obj); 2865 } 2866 errmsg_restore(saved_msg); 2867 } 2868 2869 static void 2870 objlist_clear(Objlist *list) 2871 { 2872 Objlist_Entry *elm; 2873 2874 while (!STAILQ_EMPTY(list)) { 2875 elm = STAILQ_FIRST(list); 2876 STAILQ_REMOVE_HEAD(list, link); 2877 free(elm); 2878 } 2879 } 2880 2881 static Objlist_Entry * 2882 objlist_find(Objlist *list, const Obj_Entry *obj) 2883 { 2884 Objlist_Entry *elm; 2885 2886 STAILQ_FOREACH(elm, list, link) 2887 if (elm->obj == obj) 2888 return elm; 2889 return NULL; 2890 } 2891 2892 static void 2893 objlist_init(Objlist *list) 2894 { 2895 STAILQ_INIT(list); 2896 } 2897 2898 static void 2899 objlist_push_head(Objlist *list, Obj_Entry *obj) 2900 { 2901 Objlist_Entry *elm; 2902 2903 elm = NEW(Objlist_Entry); 2904 elm->obj = obj; 2905 STAILQ_INSERT_HEAD(list, elm, link); 2906 } 2907 2908 static void 2909 objlist_push_tail(Objlist *list, Obj_Entry *obj) 2910 { 2911 Objlist_Entry *elm; 2912 2913 elm = NEW(Objlist_Entry); 2914 elm->obj = obj; 2915 STAILQ_INSERT_TAIL(list, elm, link); 2916 } 2917 2918 static void 2919 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2920 { 2921 Objlist_Entry *elm, *listelm; 2922 2923 STAILQ_FOREACH(listelm, list, link) { 2924 if (listelm->obj == listobj) 2925 break; 2926 } 2927 elm = NEW(Objlist_Entry); 2928 elm->obj = obj; 2929 if (listelm != NULL) 2930 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2931 else 2932 STAILQ_INSERT_TAIL(list, elm, link); 2933 } 2934 2935 static void 2936 objlist_remove(Objlist *list, Obj_Entry *obj) 2937 { 2938 Objlist_Entry *elm; 2939 2940 if ((elm = objlist_find(list, obj)) != NULL) { 2941 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2942 free(elm); 2943 } 2944 } 2945 2946 /* 2947 * Relocate dag rooted in the specified object. 2948 * Returns 0 on success, or -1 on failure. 2949 */ 2950 2951 static int 2952 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2953 int flags, RtldLockState *lockstate) 2954 { 2955 Objlist_Entry *elm; 2956 int error; 2957 2958 error = 0; 2959 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2960 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2961 lockstate); 2962 if (error == -1) 2963 break; 2964 } 2965 return (error); 2966 } 2967 2968 /* 2969 * Prepare for, or clean after, relocating an object marked with 2970 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 2971 * segments are remapped read-write. After relocations are done, the 2972 * segment's permissions are returned back to the modes specified in 2973 * the phdrs. If any relocation happened, or always for wired 2974 * program, COW is triggered. 2975 */ 2976 static int 2977 reloc_textrel_prot(Obj_Entry *obj, bool before) 2978 { 2979 const Elf_Phdr *ph; 2980 void *base; 2981 size_t l, sz; 2982 int prot; 2983 2984 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 2985 l--, ph++) { 2986 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 2987 continue; 2988 base = obj->relocbase + trunc_page(ph->p_vaddr); 2989 sz = round_page(ph->p_vaddr + ph->p_filesz) - 2990 trunc_page(ph->p_vaddr); 2991 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0); 2992 if (mprotect(base, sz, prot) == -1) { 2993 _rtld_error("%s: Cannot write-%sable text segment: %s", 2994 obj->path, before ? "en" : "dis", 2995 rtld_strerror(errno)); 2996 return (-1); 2997 } 2998 } 2999 return (0); 3000 } 3001 3002 /* 3003 * Relocate single object. 3004 * Returns 0 on success, or -1 on failure. 3005 */ 3006 static int 3007 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 3008 int flags, RtldLockState *lockstate) 3009 { 3010 3011 if (obj->relocated) 3012 return (0); 3013 obj->relocated = true; 3014 if (obj != rtldobj) 3015 dbg("relocating \"%s\"", obj->path); 3016 3017 if (obj->symtab == NULL || obj->strtab == NULL || 3018 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) 3019 dbg("object %s has no run-time symbol table", obj->path); 3020 3021 /* There are relocations to the write-protected text segment. */ 3022 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 3023 return (-1); 3024 3025 /* Process the non-PLT non-IFUNC relocations. */ 3026 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 3027 return (-1); 3028 3029 /* Re-protected the text segment. */ 3030 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 3031 return (-1); 3032 3033 /* Set the special PLT or GOT entries. */ 3034 init_pltgot(obj); 3035 3036 /* Process the PLT relocations. */ 3037 if (reloc_plt(obj, flags, lockstate) == -1) 3038 return (-1); 3039 /* Relocate the jump slots if we are doing immediate binding. */ 3040 if ((obj->bind_now || bind_now) && reloc_jmpslots(obj, flags, 3041 lockstate) == -1) 3042 return (-1); 3043 3044 if (!obj->mainprog && obj_enforce_relro(obj) == -1) 3045 return (-1); 3046 3047 /* 3048 * Set up the magic number and version in the Obj_Entry. These 3049 * were checked in the crt1.o from the original ElfKit, so we 3050 * set them for backward compatibility. 3051 */ 3052 obj->magic = RTLD_MAGIC; 3053 obj->version = RTLD_VERSION; 3054 3055 return (0); 3056 } 3057 3058 /* 3059 * Relocate newly-loaded shared objects. The argument is a pointer to 3060 * the Obj_Entry for the first such object. All objects from the first 3061 * to the end of the list of objects are relocated. Returns 0 on success, 3062 * or -1 on failure. 3063 */ 3064 static int 3065 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 3066 int flags, RtldLockState *lockstate) 3067 { 3068 Obj_Entry *obj; 3069 int error; 3070 3071 for (error = 0, obj = first; obj != NULL; 3072 obj = TAILQ_NEXT(obj, next)) { 3073 if (obj->marker) 3074 continue; 3075 error = relocate_object(obj, bind_now, rtldobj, flags, 3076 lockstate); 3077 if (error == -1) 3078 break; 3079 } 3080 return (error); 3081 } 3082 3083 /* 3084 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 3085 * referencing STT_GNU_IFUNC symbols is postponed till the other 3086 * relocations are done. The indirect functions specified as 3087 * ifunc are allowed to call other symbols, so we need to have 3088 * objects relocated before asking for resolution from indirects. 3089 * 3090 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 3091 * instead of the usual lazy handling of PLT slots. It is 3092 * consistent with how GNU does it. 3093 */ 3094 static int 3095 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 3096 RtldLockState *lockstate) 3097 { 3098 3099 if (obj->ifuncs_resolved) 3100 return (0); 3101 obj->ifuncs_resolved = true; 3102 if (!obj->irelative && !obj->irelative_nonplt && 3103 !((obj->bind_now || bind_now) && obj->gnu_ifunc) && 3104 !obj->non_plt_gnu_ifunc) 3105 return (0); 3106 if (obj_disable_relro(obj) == -1 || 3107 (obj->irelative && reloc_iresolve(obj, lockstate) == -1) || 3108 (obj->irelative_nonplt && reloc_iresolve_nonplt(obj, 3109 lockstate) == -1) || 3110 ((obj->bind_now || bind_now) && obj->gnu_ifunc && 3111 reloc_gnu_ifunc(obj, flags, lockstate) == -1) || 3112 (obj->non_plt_gnu_ifunc && reloc_non_plt(obj, &obj_rtld, 3113 flags | SYMLOOK_IFUNC, lockstate) == -1) || 3114 obj_enforce_relro(obj) == -1) 3115 return (-1); 3116 return (0); 3117 } 3118 3119 static int 3120 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 3121 RtldLockState *lockstate) 3122 { 3123 Objlist_Entry *elm; 3124 Obj_Entry *obj; 3125 3126 STAILQ_FOREACH(elm, list, link) { 3127 obj = elm->obj; 3128 if (obj->marker) 3129 continue; 3130 if (resolve_object_ifunc(obj, bind_now, flags, 3131 lockstate) == -1) 3132 return (-1); 3133 } 3134 return (0); 3135 } 3136 3137 /* 3138 * Cleanup procedure. It will be called (by the atexit mechanism) just 3139 * before the process exits. 3140 */ 3141 static void 3142 rtld_exit(void) 3143 { 3144 RtldLockState lockstate; 3145 3146 wlock_acquire(rtld_bind_lock, &lockstate); 3147 dbg("rtld_exit()"); 3148 objlist_call_fini(&list_fini, NULL, &lockstate); 3149 /* No need to remove the items from the list, since we are exiting. */ 3150 if (!libmap_disable) 3151 lm_fini(); 3152 lock_release(rtld_bind_lock, &lockstate); 3153 } 3154 3155 static void 3156 rtld_nop_exit(void) 3157 { 3158 } 3159 3160 /* 3161 * Iterate over a search path, translate each element, and invoke the 3162 * callback on the result. 3163 */ 3164 static void * 3165 path_enumerate(const char *path, path_enum_proc callback, 3166 const char *refobj_path, void *arg) 3167 { 3168 const char *trans; 3169 if (path == NULL) 3170 return (NULL); 3171 3172 path += strspn(path, ":;"); 3173 while (*path != '\0') { 3174 size_t len; 3175 char *res; 3176 3177 len = strcspn(path, ":;"); 3178 trans = lm_findn(refobj_path, path, len); 3179 if (trans) 3180 res = callback(trans, strlen(trans), arg); 3181 else 3182 res = callback(path, len, arg); 3183 3184 if (res != NULL) 3185 return (res); 3186 3187 path += len; 3188 path += strspn(path, ":;"); 3189 } 3190 3191 return (NULL); 3192 } 3193 3194 struct try_library_args { 3195 const char *name; 3196 size_t namelen; 3197 char *buffer; 3198 size_t buflen; 3199 int fd; 3200 }; 3201 3202 static void * 3203 try_library_path(const char *dir, size_t dirlen, void *param) 3204 { 3205 struct try_library_args *arg; 3206 int fd; 3207 3208 arg = param; 3209 if (*dir == '/' || trust) { 3210 char *pathname; 3211 3212 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 3213 return (NULL); 3214 3215 pathname = arg->buffer; 3216 strncpy(pathname, dir, dirlen); 3217 pathname[dirlen] = '/'; 3218 strcpy(pathname + dirlen + 1, arg->name); 3219 3220 dbg(" Trying \"%s\"", pathname); 3221 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY); 3222 if (fd >= 0) { 3223 dbg(" Opened \"%s\", fd %d", pathname, fd); 3224 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 3225 strcpy(pathname, arg->buffer); 3226 arg->fd = fd; 3227 return (pathname); 3228 } else { 3229 dbg(" Failed to open \"%s\": %s", 3230 pathname, rtld_strerror(errno)); 3231 } 3232 } 3233 return (NULL); 3234 } 3235 3236 static char * 3237 search_library_path(const char *name, const char *path, 3238 const char *refobj_path, int *fdp) 3239 { 3240 char *p; 3241 struct try_library_args arg; 3242 3243 if (path == NULL) 3244 return NULL; 3245 3246 arg.name = name; 3247 arg.namelen = strlen(name); 3248 arg.buffer = xmalloc(PATH_MAX); 3249 arg.buflen = PATH_MAX; 3250 arg.fd = -1; 3251 3252 p = path_enumerate(path, try_library_path, refobj_path, &arg); 3253 *fdp = arg.fd; 3254 3255 free(arg.buffer); 3256 3257 return (p); 3258 } 3259 3260 3261 /* 3262 * Finds the library with the given name using the directory descriptors 3263 * listed in the LD_LIBRARY_PATH_FDS environment variable. 3264 * 3265 * Returns a freshly-opened close-on-exec file descriptor for the library, 3266 * or -1 if the library cannot be found. 3267 */ 3268 static char * 3269 search_library_pathfds(const char *name, const char *path, int *fdp) 3270 { 3271 char *envcopy, *fdstr, *found, *last_token; 3272 size_t len; 3273 int dirfd, fd; 3274 3275 dbg("%s('%s', '%s', fdp)", __func__, name, path); 3276 3277 /* Don't load from user-specified libdirs into setuid binaries. */ 3278 if (!trust) 3279 return (NULL); 3280 3281 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 3282 if (path == NULL) 3283 return (NULL); 3284 3285 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 3286 if (name[0] == '/') { 3287 dbg("Absolute path (%s) passed to %s", name, __func__); 3288 return (NULL); 3289 } 3290 3291 /* 3292 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 3293 * copy of the path, as strtok_r rewrites separator tokens 3294 * with '\0'. 3295 */ 3296 found = NULL; 3297 envcopy = xstrdup(path); 3298 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 3299 fdstr = strtok_r(NULL, ":", &last_token)) { 3300 dirfd = parse_integer(fdstr); 3301 if (dirfd < 0) { 3302 _rtld_error("failed to parse directory FD: '%s'", 3303 fdstr); 3304 break; 3305 } 3306 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 3307 if (fd >= 0) { 3308 *fdp = fd; 3309 len = strlen(fdstr) + strlen(name) + 3; 3310 found = xmalloc(len); 3311 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 3312 _rtld_error("error generating '%d/%s'", 3313 dirfd, name); 3314 rtld_die(); 3315 } 3316 dbg("open('%s') => %d", found, fd); 3317 break; 3318 } 3319 } 3320 free(envcopy); 3321 3322 return (found); 3323 } 3324 3325 3326 int 3327 dlclose(void *handle) 3328 { 3329 RtldLockState lockstate; 3330 int error; 3331 3332 wlock_acquire(rtld_bind_lock, &lockstate); 3333 error = dlclose_locked(handle, &lockstate); 3334 lock_release(rtld_bind_lock, &lockstate); 3335 return (error); 3336 } 3337 3338 static int 3339 dlclose_locked(void *handle, RtldLockState *lockstate) 3340 { 3341 Obj_Entry *root; 3342 3343 root = dlcheck(handle); 3344 if (root == NULL) 3345 return -1; 3346 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 3347 root->path); 3348 3349 /* Unreference the object and its dependencies. */ 3350 root->dl_refcount--; 3351 3352 if (root->refcount == 1) { 3353 /* 3354 * The object will be no longer referenced, so we must unload it. 3355 * First, call the fini functions. 3356 */ 3357 objlist_call_fini(&list_fini, root, lockstate); 3358 3359 unref_dag(root); 3360 3361 /* Finish cleaning up the newly-unreferenced objects. */ 3362 GDB_STATE(RT_DELETE,&root->linkmap); 3363 unload_object(root, lockstate); 3364 GDB_STATE(RT_CONSISTENT,NULL); 3365 } else 3366 unref_dag(root); 3367 3368 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 3369 return 0; 3370 } 3371 3372 char * 3373 dlerror(void) 3374 { 3375 char *msg = error_message; 3376 error_message = NULL; 3377 return msg; 3378 } 3379 3380 /* 3381 * This function is deprecated and has no effect. 3382 */ 3383 void 3384 dllockinit(void *context, 3385 void *(*_lock_create)(void *context) __unused, 3386 void (*_rlock_acquire)(void *lock) __unused, 3387 void (*_wlock_acquire)(void *lock) __unused, 3388 void (*_lock_release)(void *lock) __unused, 3389 void (*_lock_destroy)(void *lock) __unused, 3390 void (*context_destroy)(void *context)) 3391 { 3392 static void *cur_context; 3393 static void (*cur_context_destroy)(void *); 3394 3395 /* Just destroy the context from the previous call, if necessary. */ 3396 if (cur_context_destroy != NULL) 3397 cur_context_destroy(cur_context); 3398 cur_context = context; 3399 cur_context_destroy = context_destroy; 3400 } 3401 3402 void * 3403 dlopen(const char *name, int mode) 3404 { 3405 3406 return (rtld_dlopen(name, -1, mode)); 3407 } 3408 3409 void * 3410 fdlopen(int fd, int mode) 3411 { 3412 3413 return (rtld_dlopen(NULL, fd, mode)); 3414 } 3415 3416 static void * 3417 rtld_dlopen(const char *name, int fd, int mode) 3418 { 3419 RtldLockState lockstate; 3420 int lo_flags; 3421 3422 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3423 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3424 if (ld_tracing != NULL) { 3425 rlock_acquire(rtld_bind_lock, &lockstate); 3426 if (sigsetjmp(lockstate.env, 0) != 0) 3427 lock_upgrade(rtld_bind_lock, &lockstate); 3428 environ = __DECONST(char **, *get_program_var_addr("environ", &lockstate)); 3429 lock_release(rtld_bind_lock, &lockstate); 3430 } 3431 lo_flags = RTLD_LO_DLOPEN; 3432 if (mode & RTLD_NODELETE) 3433 lo_flags |= RTLD_LO_NODELETE; 3434 if (mode & RTLD_NOLOAD) 3435 lo_flags |= RTLD_LO_NOLOAD; 3436 if (mode & RTLD_DEEPBIND) 3437 lo_flags |= RTLD_LO_DEEPBIND; 3438 if (ld_tracing != NULL) 3439 lo_flags |= RTLD_LO_TRACE | RTLD_LO_IGNSTLS; 3440 3441 return (dlopen_object(name, fd, obj_main, lo_flags, 3442 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3443 } 3444 3445 static void 3446 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate) 3447 { 3448 3449 obj->dl_refcount--; 3450 unref_dag(obj); 3451 if (obj->refcount == 0) 3452 unload_object(obj, lockstate); 3453 } 3454 3455 static Obj_Entry * 3456 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3457 int mode, RtldLockState *lockstate) 3458 { 3459 Obj_Entry *old_obj_tail; 3460 Obj_Entry *obj; 3461 Objlist initlist; 3462 RtldLockState mlockstate; 3463 int result; 3464 3465 dbg("dlopen_object name \"%s\" fd %d refobj \"%s\" lo_flags %#x mode %#x", 3466 name != NULL ? name : "<null>", fd, refobj == NULL ? "<null>" : 3467 refobj->path, lo_flags, mode); 3468 objlist_init(&initlist); 3469 3470 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3471 wlock_acquire(rtld_bind_lock, &mlockstate); 3472 lockstate = &mlockstate; 3473 } 3474 GDB_STATE(RT_ADD,NULL); 3475 3476 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 3477 obj = NULL; 3478 if (name == NULL && fd == -1) { 3479 obj = obj_main; 3480 obj->refcount++; 3481 } else { 3482 obj = load_object(name, fd, refobj, lo_flags); 3483 } 3484 3485 if (obj) { 3486 obj->dl_refcount++; 3487 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3488 objlist_push_tail(&list_global, obj); 3489 if (globallist_next(old_obj_tail) != NULL) { 3490 /* We loaded something new. */ 3491 assert(globallist_next(old_obj_tail) == obj); 3492 if ((lo_flags & RTLD_LO_DEEPBIND) != 0) 3493 obj->symbolic = true; 3494 result = 0; 3495 if ((lo_flags & (RTLD_LO_EARLY | RTLD_LO_IGNSTLS)) == 0 && 3496 obj->static_tls && !allocate_tls_offset(obj)) { 3497 _rtld_error("%s: No space available " 3498 "for static Thread Local Storage", obj->path); 3499 result = -1; 3500 } 3501 if (result != -1) 3502 result = load_needed_objects(obj, lo_flags & (RTLD_LO_DLOPEN | 3503 RTLD_LO_EARLY | RTLD_LO_IGNSTLS | RTLD_LO_TRACE)); 3504 init_dag(obj); 3505 ref_dag(obj); 3506 if (result != -1) 3507 result = rtld_verify_versions(&obj->dagmembers); 3508 if (result != -1 && ld_tracing) 3509 goto trace; 3510 if (result == -1 || relocate_object_dag(obj, 3511 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3512 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3513 lockstate) == -1) { 3514 dlopen_cleanup(obj, lockstate); 3515 obj = NULL; 3516 } else if (lo_flags & RTLD_LO_EARLY) { 3517 /* 3518 * Do not call the init functions for early loaded 3519 * filtees. The image is still not initialized enough 3520 * for them to work. 3521 * 3522 * Our object is found by the global object list and 3523 * will be ordered among all init calls done right 3524 * before transferring control to main. 3525 */ 3526 } else { 3527 /* Make list of init functions to call. */ 3528 initlist_add_objects(obj, obj, &initlist); 3529 } 3530 /* 3531 * Process all no_delete or global objects here, given 3532 * them own DAGs to prevent their dependencies from being 3533 * unloaded. This has to be done after we have loaded all 3534 * of the dependencies, so that we do not miss any. 3535 */ 3536 if (obj != NULL) 3537 process_z(obj); 3538 } else { 3539 /* 3540 * Bump the reference counts for objects on this DAG. If 3541 * this is the first dlopen() call for the object that was 3542 * already loaded as a dependency, initialize the dag 3543 * starting at it. 3544 */ 3545 init_dag(obj); 3546 ref_dag(obj); 3547 3548 if ((lo_flags & RTLD_LO_TRACE) != 0) 3549 goto trace; 3550 } 3551 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3552 obj->z_nodelete) && !obj->ref_nodel) { 3553 dbg("obj %s nodelete", obj->path); 3554 ref_dag(obj); 3555 obj->z_nodelete = obj->ref_nodel = true; 3556 } 3557 } 3558 3559 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3560 name); 3561 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3562 3563 if ((lo_flags & RTLD_LO_EARLY) == 0) { 3564 map_stacks_exec(lockstate); 3565 if (obj != NULL) 3566 distribute_static_tls(&initlist, lockstate); 3567 } 3568 3569 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3570 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3571 lockstate) == -1) { 3572 objlist_clear(&initlist); 3573 dlopen_cleanup(obj, lockstate); 3574 if (lockstate == &mlockstate) 3575 lock_release(rtld_bind_lock, lockstate); 3576 return (NULL); 3577 } 3578 3579 if (!(lo_flags & RTLD_LO_EARLY)) { 3580 /* Call the init functions. */ 3581 objlist_call_init(&initlist, lockstate); 3582 } 3583 objlist_clear(&initlist); 3584 if (lockstate == &mlockstate) 3585 lock_release(rtld_bind_lock, lockstate); 3586 return obj; 3587 trace: 3588 trace_loaded_objects(obj); 3589 if (lockstate == &mlockstate) 3590 lock_release(rtld_bind_lock, lockstate); 3591 exit(0); 3592 } 3593 3594 static void * 3595 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3596 int flags) 3597 { 3598 DoneList donelist; 3599 const Obj_Entry *obj, *defobj; 3600 const Elf_Sym *def; 3601 SymLook req; 3602 RtldLockState lockstate; 3603 tls_index ti; 3604 void *sym; 3605 int res; 3606 3607 def = NULL; 3608 defobj = NULL; 3609 symlook_init(&req, name); 3610 req.ventry = ve; 3611 req.flags = flags | SYMLOOK_IN_PLT; 3612 req.lockstate = &lockstate; 3613 3614 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3615 rlock_acquire(rtld_bind_lock, &lockstate); 3616 if (sigsetjmp(lockstate.env, 0) != 0) 3617 lock_upgrade(rtld_bind_lock, &lockstate); 3618 if (handle == NULL || handle == RTLD_NEXT || 3619 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3620 3621 if ((obj = obj_from_addr(retaddr)) == NULL) { 3622 _rtld_error("Cannot determine caller's shared object"); 3623 lock_release(rtld_bind_lock, &lockstate); 3624 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3625 return NULL; 3626 } 3627 if (handle == NULL) { /* Just the caller's shared object. */ 3628 res = symlook_obj(&req, obj); 3629 if (res == 0) { 3630 def = req.sym_out; 3631 defobj = req.defobj_out; 3632 } 3633 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3634 handle == RTLD_SELF) { /* ... caller included */ 3635 if (handle == RTLD_NEXT) 3636 obj = globallist_next(obj); 3637 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3638 if (obj->marker) 3639 continue; 3640 res = symlook_obj(&req, obj); 3641 if (res == 0) { 3642 if (def == NULL || 3643 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3644 def = req.sym_out; 3645 defobj = req.defobj_out; 3646 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3647 break; 3648 } 3649 } 3650 } 3651 /* 3652 * Search the dynamic linker itself, and possibly resolve the 3653 * symbol from there. This is how the application links to 3654 * dynamic linker services such as dlopen. 3655 */ 3656 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3657 res = symlook_obj(&req, &obj_rtld); 3658 if (res == 0) { 3659 def = req.sym_out; 3660 defobj = req.defobj_out; 3661 } 3662 } 3663 } else { 3664 assert(handle == RTLD_DEFAULT); 3665 res = symlook_default(&req, obj); 3666 if (res == 0) { 3667 defobj = req.defobj_out; 3668 def = req.sym_out; 3669 } 3670 } 3671 } else { 3672 if ((obj = dlcheck(handle)) == NULL) { 3673 lock_release(rtld_bind_lock, &lockstate); 3674 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3675 return NULL; 3676 } 3677 3678 donelist_init(&donelist); 3679 if (obj->mainprog) { 3680 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3681 res = symlook_global(&req, &donelist); 3682 if (res == 0) { 3683 def = req.sym_out; 3684 defobj = req.defobj_out; 3685 } 3686 /* 3687 * Search the dynamic linker itself, and possibly resolve the 3688 * symbol from there. This is how the application links to 3689 * dynamic linker services such as dlopen. 3690 */ 3691 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3692 res = symlook_obj(&req, &obj_rtld); 3693 if (res == 0) { 3694 def = req.sym_out; 3695 defobj = req.defobj_out; 3696 } 3697 } 3698 } 3699 else { 3700 /* Search the whole DAG rooted at the given object. */ 3701 res = symlook_list(&req, &obj->dagmembers, &donelist); 3702 if (res == 0) { 3703 def = req.sym_out; 3704 defobj = req.defobj_out; 3705 } 3706 } 3707 } 3708 3709 if (def != NULL) { 3710 lock_release(rtld_bind_lock, &lockstate); 3711 3712 /* 3713 * The value required by the caller is derived from the value 3714 * of the symbol. this is simply the relocated value of the 3715 * symbol. 3716 */ 3717 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3718 sym = make_function_pointer(def, defobj); 3719 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3720 sym = rtld_resolve_ifunc(defobj, def); 3721 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3722 ti.ti_module = defobj->tlsindex; 3723 ti.ti_offset = def->st_value; 3724 sym = __tls_get_addr(&ti); 3725 } else 3726 sym = defobj->relocbase + def->st_value; 3727 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3728 return (sym); 3729 } 3730 3731 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "", 3732 ve != NULL ? ve->name : ""); 3733 lock_release(rtld_bind_lock, &lockstate); 3734 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3735 return NULL; 3736 } 3737 3738 void * 3739 dlsym(void *handle, const char *name) 3740 { 3741 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3742 SYMLOOK_DLSYM); 3743 } 3744 3745 dlfunc_t 3746 dlfunc(void *handle, const char *name) 3747 { 3748 union { 3749 void *d; 3750 dlfunc_t f; 3751 } rv; 3752 3753 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3754 SYMLOOK_DLSYM); 3755 return (rv.f); 3756 } 3757 3758 void * 3759 dlvsym(void *handle, const char *name, const char *version) 3760 { 3761 Ver_Entry ventry; 3762 3763 ventry.name = version; 3764 ventry.file = NULL; 3765 ventry.hash = elf_hash(version); 3766 ventry.flags= 0; 3767 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3768 SYMLOOK_DLSYM); 3769 } 3770 3771 int 3772 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3773 { 3774 const Obj_Entry *obj; 3775 RtldLockState lockstate; 3776 3777 rlock_acquire(rtld_bind_lock, &lockstate); 3778 obj = obj_from_addr(addr); 3779 if (obj == NULL) { 3780 _rtld_error("No shared object contains address"); 3781 lock_release(rtld_bind_lock, &lockstate); 3782 return (0); 3783 } 3784 rtld_fill_dl_phdr_info(obj, phdr_info); 3785 lock_release(rtld_bind_lock, &lockstate); 3786 return (1); 3787 } 3788 3789 int 3790 dladdr(const void *addr, Dl_info *info) 3791 { 3792 const Obj_Entry *obj; 3793 const Elf_Sym *def; 3794 void *symbol_addr; 3795 unsigned long symoffset; 3796 RtldLockState lockstate; 3797 3798 rlock_acquire(rtld_bind_lock, &lockstate); 3799 obj = obj_from_addr(addr); 3800 if (obj == NULL) { 3801 _rtld_error("No shared object contains address"); 3802 lock_release(rtld_bind_lock, &lockstate); 3803 return 0; 3804 } 3805 info->dli_fname = obj->path; 3806 info->dli_fbase = obj->mapbase; 3807 info->dli_saddr = (void *)0; 3808 info->dli_sname = NULL; 3809 3810 /* 3811 * Walk the symbol list looking for the symbol whose address is 3812 * closest to the address sent in. 3813 */ 3814 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3815 def = obj->symtab + symoffset; 3816 3817 /* 3818 * For skip the symbol if st_shndx is either SHN_UNDEF or 3819 * SHN_COMMON. 3820 */ 3821 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3822 continue; 3823 3824 /* 3825 * If the symbol is greater than the specified address, or if it 3826 * is further away from addr than the current nearest symbol, 3827 * then reject it. 3828 */ 3829 symbol_addr = obj->relocbase + def->st_value; 3830 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3831 continue; 3832 3833 /* Update our idea of the nearest symbol. */ 3834 info->dli_sname = obj->strtab + def->st_name; 3835 info->dli_saddr = symbol_addr; 3836 3837 /* Exact match? */ 3838 if (info->dli_saddr == addr) 3839 break; 3840 } 3841 lock_release(rtld_bind_lock, &lockstate); 3842 return 1; 3843 } 3844 3845 int 3846 dlinfo(void *handle, int request, void *p) 3847 { 3848 const Obj_Entry *obj; 3849 RtldLockState lockstate; 3850 int error; 3851 3852 rlock_acquire(rtld_bind_lock, &lockstate); 3853 3854 if (handle == NULL || handle == RTLD_SELF) { 3855 void *retaddr; 3856 3857 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3858 if ((obj = obj_from_addr(retaddr)) == NULL) 3859 _rtld_error("Cannot determine caller's shared object"); 3860 } else 3861 obj = dlcheck(handle); 3862 3863 if (obj == NULL) { 3864 lock_release(rtld_bind_lock, &lockstate); 3865 return (-1); 3866 } 3867 3868 error = 0; 3869 switch (request) { 3870 case RTLD_DI_LINKMAP: 3871 *((struct link_map const **)p) = &obj->linkmap; 3872 break; 3873 case RTLD_DI_ORIGIN: 3874 error = rtld_dirname(obj->path, p); 3875 break; 3876 3877 case RTLD_DI_SERINFOSIZE: 3878 case RTLD_DI_SERINFO: 3879 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3880 break; 3881 3882 default: 3883 _rtld_error("Invalid request %d passed to dlinfo()", request); 3884 error = -1; 3885 } 3886 3887 lock_release(rtld_bind_lock, &lockstate); 3888 3889 return (error); 3890 } 3891 3892 static void 3893 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3894 { 3895 3896 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3897 phdr_info->dlpi_name = obj->path; 3898 phdr_info->dlpi_phdr = obj->phdr; 3899 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3900 phdr_info->dlpi_tls_modid = obj->tlsindex; 3901 phdr_info->dlpi_tls_data = obj->tlsinit; 3902 phdr_info->dlpi_adds = obj_loads; 3903 phdr_info->dlpi_subs = obj_loads - obj_count; 3904 } 3905 3906 int 3907 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3908 { 3909 struct dl_phdr_info phdr_info; 3910 Obj_Entry *obj, marker; 3911 RtldLockState bind_lockstate, phdr_lockstate; 3912 int error; 3913 3914 init_marker(&marker); 3915 error = 0; 3916 3917 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3918 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3919 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 3920 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 3921 rtld_fill_dl_phdr_info(obj, &phdr_info); 3922 hold_object(obj); 3923 lock_release(rtld_bind_lock, &bind_lockstate); 3924 3925 error = callback(&phdr_info, sizeof phdr_info, param); 3926 3927 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3928 unhold_object(obj); 3929 obj = globallist_next(&marker); 3930 TAILQ_REMOVE(&obj_list, &marker, next); 3931 if (error != 0) { 3932 lock_release(rtld_bind_lock, &bind_lockstate); 3933 lock_release(rtld_phdr_lock, &phdr_lockstate); 3934 return (error); 3935 } 3936 } 3937 3938 if (error == 0) { 3939 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3940 lock_release(rtld_bind_lock, &bind_lockstate); 3941 error = callback(&phdr_info, sizeof(phdr_info), param); 3942 } 3943 lock_release(rtld_phdr_lock, &phdr_lockstate); 3944 return (error); 3945 } 3946 3947 static void * 3948 fill_search_info(const char *dir, size_t dirlen, void *param) 3949 { 3950 struct fill_search_info_args *arg; 3951 3952 arg = param; 3953 3954 if (arg->request == RTLD_DI_SERINFOSIZE) { 3955 arg->serinfo->dls_cnt ++; 3956 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3957 } else { 3958 struct dl_serpath *s_entry; 3959 3960 s_entry = arg->serpath; 3961 s_entry->dls_name = arg->strspace; 3962 s_entry->dls_flags = arg->flags; 3963 3964 strncpy(arg->strspace, dir, dirlen); 3965 arg->strspace[dirlen] = '\0'; 3966 3967 arg->strspace += dirlen + 1; 3968 arg->serpath++; 3969 } 3970 3971 return (NULL); 3972 } 3973 3974 static int 3975 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3976 { 3977 struct dl_serinfo _info; 3978 struct fill_search_info_args args; 3979 3980 args.request = RTLD_DI_SERINFOSIZE; 3981 args.serinfo = &_info; 3982 3983 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3984 _info.dls_cnt = 0; 3985 3986 path_enumerate(obj->rpath, fill_search_info, NULL, &args); 3987 path_enumerate(ld_library_path, fill_search_info, NULL, &args); 3988 path_enumerate(obj->runpath, fill_search_info, NULL, &args); 3989 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args); 3990 if (!obj->z_nodeflib) 3991 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args); 3992 3993 3994 if (request == RTLD_DI_SERINFOSIZE) { 3995 info->dls_size = _info.dls_size; 3996 info->dls_cnt = _info.dls_cnt; 3997 return (0); 3998 } 3999 4000 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 4001 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 4002 return (-1); 4003 } 4004 4005 args.request = RTLD_DI_SERINFO; 4006 args.serinfo = info; 4007 args.serpath = &info->dls_serpath[0]; 4008 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 4009 4010 args.flags = LA_SER_RUNPATH; 4011 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL) 4012 return (-1); 4013 4014 args.flags = LA_SER_LIBPATH; 4015 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL) 4016 return (-1); 4017 4018 args.flags = LA_SER_RUNPATH; 4019 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL) 4020 return (-1); 4021 4022 args.flags = LA_SER_CONFIG; 4023 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args) 4024 != NULL) 4025 return (-1); 4026 4027 args.flags = LA_SER_DEFAULT; 4028 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path, 4029 fill_search_info, NULL, &args) != NULL) 4030 return (-1); 4031 return (0); 4032 } 4033 4034 static int 4035 rtld_dirname(const char *path, char *bname) 4036 { 4037 const char *endp; 4038 4039 /* Empty or NULL string gets treated as "." */ 4040 if (path == NULL || *path == '\0') { 4041 bname[0] = '.'; 4042 bname[1] = '\0'; 4043 return (0); 4044 } 4045 4046 /* Strip trailing slashes */ 4047 endp = path + strlen(path) - 1; 4048 while (endp > path && *endp == '/') 4049 endp--; 4050 4051 /* Find the start of the dir */ 4052 while (endp > path && *endp != '/') 4053 endp--; 4054 4055 /* Either the dir is "/" or there are no slashes */ 4056 if (endp == path) { 4057 bname[0] = *endp == '/' ? '/' : '.'; 4058 bname[1] = '\0'; 4059 return (0); 4060 } else { 4061 do { 4062 endp--; 4063 } while (endp > path && *endp == '/'); 4064 } 4065 4066 if (endp - path + 2 > PATH_MAX) 4067 { 4068 _rtld_error("Filename is too long: %s", path); 4069 return(-1); 4070 } 4071 4072 strncpy(bname, path, endp - path + 1); 4073 bname[endp - path + 1] = '\0'; 4074 return (0); 4075 } 4076 4077 static int 4078 rtld_dirname_abs(const char *path, char *base) 4079 { 4080 char *last; 4081 4082 if (realpath(path, base) == NULL) { 4083 _rtld_error("realpath \"%s\" failed (%s)", path, 4084 rtld_strerror(errno)); 4085 return (-1); 4086 } 4087 dbg("%s -> %s", path, base); 4088 last = strrchr(base, '/'); 4089 if (last == NULL) { 4090 _rtld_error("non-abs result from realpath \"%s\"", path); 4091 return (-1); 4092 } 4093 if (last != base) 4094 *last = '\0'; 4095 return (0); 4096 } 4097 4098 static void 4099 linkmap_add(Obj_Entry *obj) 4100 { 4101 struct link_map *l, *prev; 4102 4103 l = &obj->linkmap; 4104 l->l_name = obj->path; 4105 l->l_base = obj->mapbase; 4106 l->l_ld = obj->dynamic; 4107 l->l_addr = obj->relocbase; 4108 4109 if (r_debug.r_map == NULL) { 4110 r_debug.r_map = l; 4111 return; 4112 } 4113 4114 /* 4115 * Scan to the end of the list, but not past the entry for the 4116 * dynamic linker, which we want to keep at the very end. 4117 */ 4118 for (prev = r_debug.r_map; 4119 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 4120 prev = prev->l_next) 4121 ; 4122 4123 /* Link in the new entry. */ 4124 l->l_prev = prev; 4125 l->l_next = prev->l_next; 4126 if (l->l_next != NULL) 4127 l->l_next->l_prev = l; 4128 prev->l_next = l; 4129 } 4130 4131 static void 4132 linkmap_delete(Obj_Entry *obj) 4133 { 4134 struct link_map *l; 4135 4136 l = &obj->linkmap; 4137 if (l->l_prev == NULL) { 4138 if ((r_debug.r_map = l->l_next) != NULL) 4139 l->l_next->l_prev = NULL; 4140 return; 4141 } 4142 4143 if ((l->l_prev->l_next = l->l_next) != NULL) 4144 l->l_next->l_prev = l->l_prev; 4145 } 4146 4147 /* 4148 * Function for the debugger to set a breakpoint on to gain control. 4149 * 4150 * The two parameters allow the debugger to easily find and determine 4151 * what the runtime loader is doing and to whom it is doing it. 4152 * 4153 * When the loadhook trap is hit (r_debug_state, set at program 4154 * initialization), the arguments can be found on the stack: 4155 * 4156 * +8 struct link_map *m 4157 * +4 struct r_debug *rd 4158 * +0 RetAddr 4159 */ 4160 void 4161 r_debug_state(struct r_debug* rd __unused, struct link_map *m __unused) 4162 { 4163 /* 4164 * The following is a hack to force the compiler to emit calls to 4165 * this function, even when optimizing. If the function is empty, 4166 * the compiler is not obliged to emit any code for calls to it, 4167 * even when marked __noinline. However, gdb depends on those 4168 * calls being made. 4169 */ 4170 __compiler_membar(); 4171 } 4172 4173 /* 4174 * A function called after init routines have completed. This can be used to 4175 * break before a program's entry routine is called, and can be used when 4176 * main is not available in the symbol table. 4177 */ 4178 void 4179 _r_debug_postinit(struct link_map *m __unused) 4180 { 4181 4182 /* See r_debug_state(). */ 4183 __compiler_membar(); 4184 } 4185 4186 static void 4187 release_object(Obj_Entry *obj) 4188 { 4189 4190 if (obj->holdcount > 0) { 4191 obj->unholdfree = true; 4192 return; 4193 } 4194 munmap(obj->mapbase, obj->mapsize); 4195 linkmap_delete(obj); 4196 obj_free(obj); 4197 } 4198 4199 /* 4200 * Get address of the pointer variable in the main program. 4201 * Prefer non-weak symbol over the weak one. 4202 */ 4203 static const void ** 4204 get_program_var_addr(const char *name, RtldLockState *lockstate) 4205 { 4206 SymLook req; 4207 DoneList donelist; 4208 4209 symlook_init(&req, name); 4210 req.lockstate = lockstate; 4211 donelist_init(&donelist); 4212 if (symlook_global(&req, &donelist) != 0) 4213 return (NULL); 4214 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 4215 return ((const void **)make_function_pointer(req.sym_out, 4216 req.defobj_out)); 4217 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 4218 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 4219 else 4220 return ((const void **)(req.defobj_out->relocbase + 4221 req.sym_out->st_value)); 4222 } 4223 4224 /* 4225 * Set a pointer variable in the main program to the given value. This 4226 * is used to set key variables such as "environ" before any of the 4227 * init functions are called. 4228 */ 4229 static void 4230 set_program_var(const char *name, const void *value) 4231 { 4232 const void **addr; 4233 4234 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 4235 dbg("\"%s\": *%p <-- %p", name, addr, value); 4236 *addr = value; 4237 } 4238 } 4239 4240 /* 4241 * Search the global objects, including dependencies and main object, 4242 * for the given symbol. 4243 */ 4244 static int 4245 symlook_global(SymLook *req, DoneList *donelist) 4246 { 4247 SymLook req1; 4248 const Objlist_Entry *elm; 4249 int res; 4250 4251 symlook_init_from_req(&req1, req); 4252 4253 /* Search all objects loaded at program start up. */ 4254 if (req->defobj_out == NULL || 4255 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4256 res = symlook_list(&req1, &list_main, donelist); 4257 if (res == 0 && (req->defobj_out == NULL || 4258 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4259 req->sym_out = req1.sym_out; 4260 req->defobj_out = req1.defobj_out; 4261 assert(req->defobj_out != NULL); 4262 } 4263 } 4264 4265 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 4266 STAILQ_FOREACH(elm, &list_global, link) { 4267 if (req->defobj_out != NULL && 4268 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4269 break; 4270 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 4271 if (res == 0 && (req->defobj_out == NULL || 4272 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4273 req->sym_out = req1.sym_out; 4274 req->defobj_out = req1.defobj_out; 4275 assert(req->defobj_out != NULL); 4276 } 4277 } 4278 4279 return (req->sym_out != NULL ? 0 : ESRCH); 4280 } 4281 4282 /* 4283 * Given a symbol name in a referencing object, find the corresponding 4284 * definition of the symbol. Returns a pointer to the symbol, or NULL if 4285 * no definition was found. Returns a pointer to the Obj_Entry of the 4286 * defining object via the reference parameter DEFOBJ_OUT. 4287 */ 4288 static int 4289 symlook_default(SymLook *req, const Obj_Entry *refobj) 4290 { 4291 DoneList donelist; 4292 const Objlist_Entry *elm; 4293 SymLook req1; 4294 int res; 4295 4296 donelist_init(&donelist); 4297 symlook_init_from_req(&req1, req); 4298 4299 /* 4300 * Look first in the referencing object if linked symbolically, 4301 * and similarly handle protected symbols. 4302 */ 4303 res = symlook_obj(&req1, refobj); 4304 if (res == 0 && (refobj->symbolic || 4305 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) { 4306 req->sym_out = req1.sym_out; 4307 req->defobj_out = req1.defobj_out; 4308 assert(req->defobj_out != NULL); 4309 } 4310 if (refobj->symbolic || req->defobj_out != NULL) 4311 donelist_check(&donelist, refobj); 4312 4313 symlook_global(req, &donelist); 4314 4315 /* Search all dlopened DAGs containing the referencing object. */ 4316 STAILQ_FOREACH(elm, &refobj->dldags, link) { 4317 if (req->sym_out != NULL && 4318 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4319 break; 4320 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 4321 if (res == 0 && (req->sym_out == NULL || 4322 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4323 req->sym_out = req1.sym_out; 4324 req->defobj_out = req1.defobj_out; 4325 assert(req->defobj_out != NULL); 4326 } 4327 } 4328 4329 /* 4330 * Search the dynamic linker itself, and possibly resolve the 4331 * symbol from there. This is how the application links to 4332 * dynamic linker services such as dlopen. 4333 */ 4334 if (req->sym_out == NULL || 4335 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4336 res = symlook_obj(&req1, &obj_rtld); 4337 if (res == 0) { 4338 req->sym_out = req1.sym_out; 4339 req->defobj_out = req1.defobj_out; 4340 assert(req->defobj_out != NULL); 4341 } 4342 } 4343 4344 return (req->sym_out != NULL ? 0 : ESRCH); 4345 } 4346 4347 static int 4348 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 4349 { 4350 const Elf_Sym *def; 4351 const Obj_Entry *defobj; 4352 const Objlist_Entry *elm; 4353 SymLook req1; 4354 int res; 4355 4356 def = NULL; 4357 defobj = NULL; 4358 STAILQ_FOREACH(elm, objlist, link) { 4359 if (donelist_check(dlp, elm->obj)) 4360 continue; 4361 symlook_init_from_req(&req1, req); 4362 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 4363 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4364 def = req1.sym_out; 4365 defobj = req1.defobj_out; 4366 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4367 break; 4368 } 4369 } 4370 } 4371 if (def != NULL) { 4372 req->sym_out = def; 4373 req->defobj_out = defobj; 4374 return (0); 4375 } 4376 return (ESRCH); 4377 } 4378 4379 /* 4380 * Search the chain of DAGS cointed to by the given Needed_Entry 4381 * for a symbol of the given name. Each DAG is scanned completely 4382 * before advancing to the next one. Returns a pointer to the symbol, 4383 * or NULL if no definition was found. 4384 */ 4385 static int 4386 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 4387 { 4388 const Elf_Sym *def; 4389 const Needed_Entry *n; 4390 const Obj_Entry *defobj; 4391 SymLook req1; 4392 int res; 4393 4394 def = NULL; 4395 defobj = NULL; 4396 symlook_init_from_req(&req1, req); 4397 for (n = needed; n != NULL; n = n->next) { 4398 if (n->obj == NULL || 4399 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 4400 continue; 4401 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4402 def = req1.sym_out; 4403 defobj = req1.defobj_out; 4404 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4405 break; 4406 } 4407 } 4408 if (def != NULL) { 4409 req->sym_out = def; 4410 req->defobj_out = defobj; 4411 return (0); 4412 } 4413 return (ESRCH); 4414 } 4415 4416 /* 4417 * Search the symbol table of a single shared object for a symbol of 4418 * the given name and version, if requested. Returns a pointer to the 4419 * symbol, or NULL if no definition was found. If the object is 4420 * filter, return filtered symbol from filtee. 4421 * 4422 * The symbol's hash value is passed in for efficiency reasons; that 4423 * eliminates many recomputations of the hash value. 4424 */ 4425 int 4426 symlook_obj(SymLook *req, const Obj_Entry *obj) 4427 { 4428 DoneList donelist; 4429 SymLook req1; 4430 int flags, res, mres; 4431 4432 /* 4433 * If there is at least one valid hash at this point, we prefer to 4434 * use the faster GNU version if available. 4435 */ 4436 if (obj->valid_hash_gnu) 4437 mres = symlook_obj1_gnu(req, obj); 4438 else if (obj->valid_hash_sysv) 4439 mres = symlook_obj1_sysv(req, obj); 4440 else 4441 return (EINVAL); 4442 4443 if (mres == 0) { 4444 if (obj->needed_filtees != NULL) { 4445 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4446 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4447 donelist_init(&donelist); 4448 symlook_init_from_req(&req1, req); 4449 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 4450 if (res == 0) { 4451 req->sym_out = req1.sym_out; 4452 req->defobj_out = req1.defobj_out; 4453 } 4454 return (res); 4455 } 4456 if (obj->needed_aux_filtees != NULL) { 4457 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4458 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4459 donelist_init(&donelist); 4460 symlook_init_from_req(&req1, req); 4461 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 4462 if (res == 0) { 4463 req->sym_out = req1.sym_out; 4464 req->defobj_out = req1.defobj_out; 4465 return (res); 4466 } 4467 } 4468 } 4469 return (mres); 4470 } 4471 4472 /* Symbol match routine common to both hash functions */ 4473 static bool 4474 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4475 const unsigned long symnum) 4476 { 4477 Elf_Versym verndx; 4478 const Elf_Sym *symp; 4479 const char *strp; 4480 4481 symp = obj->symtab + symnum; 4482 strp = obj->strtab + symp->st_name; 4483 4484 switch (ELF_ST_TYPE(symp->st_info)) { 4485 case STT_FUNC: 4486 case STT_NOTYPE: 4487 case STT_OBJECT: 4488 case STT_COMMON: 4489 case STT_GNU_IFUNC: 4490 if (symp->st_value == 0) 4491 return (false); 4492 /* fallthrough */ 4493 case STT_TLS: 4494 if (symp->st_shndx != SHN_UNDEF) 4495 break; 4496 #ifndef __mips__ 4497 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4498 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4499 break; 4500 #endif 4501 /* fallthrough */ 4502 default: 4503 return (false); 4504 } 4505 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4506 return (false); 4507 4508 if (req->ventry == NULL) { 4509 if (obj->versyms != NULL) { 4510 verndx = VER_NDX(obj->versyms[symnum]); 4511 if (verndx > obj->vernum) { 4512 _rtld_error( 4513 "%s: symbol %s references wrong version %d", 4514 obj->path, obj->strtab + symnum, verndx); 4515 return (false); 4516 } 4517 /* 4518 * If we are not called from dlsym (i.e. this 4519 * is a normal relocation from unversioned 4520 * binary), accept the symbol immediately if 4521 * it happens to have first version after this 4522 * shared object became versioned. Otherwise, 4523 * if symbol is versioned and not hidden, 4524 * remember it. If it is the only symbol with 4525 * this name exported by the shared object, it 4526 * will be returned as a match by the calling 4527 * function. If symbol is global (verndx < 2) 4528 * accept it unconditionally. 4529 */ 4530 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4531 verndx == VER_NDX_GIVEN) { 4532 result->sym_out = symp; 4533 return (true); 4534 } 4535 else if (verndx >= VER_NDX_GIVEN) { 4536 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4537 == 0) { 4538 if (result->vsymp == NULL) 4539 result->vsymp = symp; 4540 result->vcount++; 4541 } 4542 return (false); 4543 } 4544 } 4545 result->sym_out = symp; 4546 return (true); 4547 } 4548 if (obj->versyms == NULL) { 4549 if (object_match_name(obj, req->ventry->name)) { 4550 _rtld_error("%s: object %s should provide version %s " 4551 "for symbol %s", obj_rtld.path, obj->path, 4552 req->ventry->name, obj->strtab + symnum); 4553 return (false); 4554 } 4555 } else { 4556 verndx = VER_NDX(obj->versyms[symnum]); 4557 if (verndx > obj->vernum) { 4558 _rtld_error("%s: symbol %s references wrong version %d", 4559 obj->path, obj->strtab + symnum, verndx); 4560 return (false); 4561 } 4562 if (obj->vertab[verndx].hash != req->ventry->hash || 4563 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4564 /* 4565 * Version does not match. Look if this is a 4566 * global symbol and if it is not hidden. If 4567 * global symbol (verndx < 2) is available, 4568 * use it. Do not return symbol if we are 4569 * called by dlvsym, because dlvsym looks for 4570 * a specific version and default one is not 4571 * what dlvsym wants. 4572 */ 4573 if ((req->flags & SYMLOOK_DLSYM) || 4574 (verndx >= VER_NDX_GIVEN) || 4575 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4576 return (false); 4577 } 4578 } 4579 result->sym_out = symp; 4580 return (true); 4581 } 4582 4583 /* 4584 * Search for symbol using SysV hash function. 4585 * obj->buckets is known not to be NULL at this point; the test for this was 4586 * performed with the obj->valid_hash_sysv assignment. 4587 */ 4588 static int 4589 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4590 { 4591 unsigned long symnum; 4592 Sym_Match_Result matchres; 4593 4594 matchres.sym_out = NULL; 4595 matchres.vsymp = NULL; 4596 matchres.vcount = 0; 4597 4598 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4599 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4600 if (symnum >= obj->nchains) 4601 return (ESRCH); /* Bad object */ 4602 4603 if (matched_symbol(req, obj, &matchres, symnum)) { 4604 req->sym_out = matchres.sym_out; 4605 req->defobj_out = obj; 4606 return (0); 4607 } 4608 } 4609 if (matchres.vcount == 1) { 4610 req->sym_out = matchres.vsymp; 4611 req->defobj_out = obj; 4612 return (0); 4613 } 4614 return (ESRCH); 4615 } 4616 4617 /* Search for symbol using GNU hash function */ 4618 static int 4619 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4620 { 4621 Elf_Addr bloom_word; 4622 const Elf32_Word *hashval; 4623 Elf32_Word bucket; 4624 Sym_Match_Result matchres; 4625 unsigned int h1, h2; 4626 unsigned long symnum; 4627 4628 matchres.sym_out = NULL; 4629 matchres.vsymp = NULL; 4630 matchres.vcount = 0; 4631 4632 /* Pick right bitmask word from Bloom filter array */ 4633 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4634 obj->maskwords_bm_gnu]; 4635 4636 /* Calculate modulus word size of gnu hash and its derivative */ 4637 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4638 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4639 4640 /* Filter out the "definitely not in set" queries */ 4641 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4642 return (ESRCH); 4643 4644 /* Locate hash chain and corresponding value element*/ 4645 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4646 if (bucket == 0) 4647 return (ESRCH); 4648 hashval = &obj->chain_zero_gnu[bucket]; 4649 do { 4650 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4651 symnum = hashval - obj->chain_zero_gnu; 4652 if (matched_symbol(req, obj, &matchres, symnum)) { 4653 req->sym_out = matchres.sym_out; 4654 req->defobj_out = obj; 4655 return (0); 4656 } 4657 } 4658 } while ((*hashval++ & 1) == 0); 4659 if (matchres.vcount == 1) { 4660 req->sym_out = matchres.vsymp; 4661 req->defobj_out = obj; 4662 return (0); 4663 } 4664 return (ESRCH); 4665 } 4666 4667 static void 4668 trace_loaded_objects(Obj_Entry *obj) 4669 { 4670 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4671 int c; 4672 4673 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL) 4674 main_local = ""; 4675 4676 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL) 4677 fmt1 = "\t%o => %p (%x)\n"; 4678 4679 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL) 4680 fmt2 = "\t%o (%x)\n"; 4681 4682 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL")); 4683 4684 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4685 Needed_Entry *needed; 4686 const char *name, *path; 4687 bool is_lib; 4688 4689 if (obj->marker) 4690 continue; 4691 if (list_containers && obj->needed != NULL) 4692 rtld_printf("%s:\n", obj->path); 4693 for (needed = obj->needed; needed; needed = needed->next) { 4694 if (needed->obj != NULL) { 4695 if (needed->obj->traced && !list_containers) 4696 continue; 4697 needed->obj->traced = true; 4698 path = needed->obj->path; 4699 } else 4700 path = "not found"; 4701 4702 name = obj->strtab + needed->name; 4703 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4704 4705 fmt = is_lib ? fmt1 : fmt2; 4706 while ((c = *fmt++) != '\0') { 4707 switch (c) { 4708 default: 4709 rtld_putchar(c); 4710 continue; 4711 case '\\': 4712 switch (c = *fmt) { 4713 case '\0': 4714 continue; 4715 case 'n': 4716 rtld_putchar('\n'); 4717 break; 4718 case 't': 4719 rtld_putchar('\t'); 4720 break; 4721 } 4722 break; 4723 case '%': 4724 switch (c = *fmt) { 4725 case '\0': 4726 continue; 4727 case '%': 4728 default: 4729 rtld_putchar(c); 4730 break; 4731 case 'A': 4732 rtld_putstr(main_local); 4733 break; 4734 case 'a': 4735 rtld_putstr(obj_main->path); 4736 break; 4737 case 'o': 4738 rtld_putstr(name); 4739 break; 4740 #if 0 4741 case 'm': 4742 rtld_printf("%d", sodp->sod_major); 4743 break; 4744 case 'n': 4745 rtld_printf("%d", sodp->sod_minor); 4746 break; 4747 #endif 4748 case 'p': 4749 rtld_putstr(path); 4750 break; 4751 case 'x': 4752 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4753 0); 4754 break; 4755 } 4756 break; 4757 } 4758 ++fmt; 4759 } 4760 } 4761 } 4762 } 4763 4764 /* 4765 * Unload a dlopened object and its dependencies from memory and from 4766 * our data structures. It is assumed that the DAG rooted in the 4767 * object has already been unreferenced, and that the object has a 4768 * reference count of 0. 4769 */ 4770 static void 4771 unload_object(Obj_Entry *root, RtldLockState *lockstate) 4772 { 4773 Obj_Entry marker, *obj, *next; 4774 4775 assert(root->refcount == 0); 4776 4777 /* 4778 * Pass over the DAG removing unreferenced objects from 4779 * appropriate lists. 4780 */ 4781 unlink_object(root); 4782 4783 /* Unmap all objects that are no longer referenced. */ 4784 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) { 4785 next = TAILQ_NEXT(obj, next); 4786 if (obj->marker || obj->refcount != 0) 4787 continue; 4788 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 4789 obj->mapsize, 0, obj->path); 4790 dbg("unloading \"%s\"", obj->path); 4791 /* 4792 * Unlink the object now to prevent new references from 4793 * being acquired while the bind lock is dropped in 4794 * recursive dlclose() invocations. 4795 */ 4796 TAILQ_REMOVE(&obj_list, obj, next); 4797 obj_count--; 4798 4799 if (obj->filtees_loaded) { 4800 if (next != NULL) { 4801 init_marker(&marker); 4802 TAILQ_INSERT_BEFORE(next, &marker, next); 4803 unload_filtees(obj, lockstate); 4804 next = TAILQ_NEXT(&marker, next); 4805 TAILQ_REMOVE(&obj_list, &marker, next); 4806 } else 4807 unload_filtees(obj, lockstate); 4808 } 4809 release_object(obj); 4810 } 4811 } 4812 4813 static void 4814 unlink_object(Obj_Entry *root) 4815 { 4816 Objlist_Entry *elm; 4817 4818 if (root->refcount == 0) { 4819 /* Remove the object from the RTLD_GLOBAL list. */ 4820 objlist_remove(&list_global, root); 4821 4822 /* Remove the object from all objects' DAG lists. */ 4823 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4824 objlist_remove(&elm->obj->dldags, root); 4825 if (elm->obj != root) 4826 unlink_object(elm->obj); 4827 } 4828 } 4829 } 4830 4831 static void 4832 ref_dag(Obj_Entry *root) 4833 { 4834 Objlist_Entry *elm; 4835 4836 assert(root->dag_inited); 4837 STAILQ_FOREACH(elm, &root->dagmembers, link) 4838 elm->obj->refcount++; 4839 } 4840 4841 static void 4842 unref_dag(Obj_Entry *root) 4843 { 4844 Objlist_Entry *elm; 4845 4846 assert(root->dag_inited); 4847 STAILQ_FOREACH(elm, &root->dagmembers, link) 4848 elm->obj->refcount--; 4849 } 4850 4851 /* 4852 * Common code for MD __tls_get_addr(). 4853 */ 4854 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4855 static void * 4856 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4857 { 4858 Elf_Addr *newdtv, *dtv; 4859 RtldLockState lockstate; 4860 int to_copy; 4861 4862 dtv = *dtvp; 4863 /* Check dtv generation in case new modules have arrived */ 4864 if (dtv[0] != tls_dtv_generation) { 4865 wlock_acquire(rtld_bind_lock, &lockstate); 4866 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4867 to_copy = dtv[1]; 4868 if (to_copy > tls_max_index) 4869 to_copy = tls_max_index; 4870 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4871 newdtv[0] = tls_dtv_generation; 4872 newdtv[1] = tls_max_index; 4873 free(dtv); 4874 lock_release(rtld_bind_lock, &lockstate); 4875 dtv = *dtvp = newdtv; 4876 } 4877 4878 /* Dynamically allocate module TLS if necessary */ 4879 if (dtv[index + 1] == 0) { 4880 /* Signal safe, wlock will block out signals. */ 4881 wlock_acquire(rtld_bind_lock, &lockstate); 4882 if (!dtv[index + 1]) 4883 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4884 lock_release(rtld_bind_lock, &lockstate); 4885 } 4886 return ((void *)(dtv[index + 1] + offset)); 4887 } 4888 4889 void * 4890 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4891 { 4892 Elf_Addr *dtv; 4893 4894 dtv = *dtvp; 4895 /* Check dtv generation in case new modules have arrived */ 4896 if (__predict_true(dtv[0] == tls_dtv_generation && 4897 dtv[index + 1] != 0)) 4898 return ((void *)(dtv[index + 1] + offset)); 4899 return (tls_get_addr_slow(dtvp, index, offset)); 4900 } 4901 4902 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \ 4903 defined(__powerpc__) || defined(__riscv) 4904 4905 /* 4906 * Return pointer to allocated TLS block 4907 */ 4908 static void * 4909 get_tls_block_ptr(void *tcb, size_t tcbsize) 4910 { 4911 size_t extra_size, post_size, pre_size, tls_block_size; 4912 size_t tls_init_align; 4913 4914 tls_init_align = MAX(obj_main->tlsalign, 1); 4915 4916 /* Compute fragments sizes. */ 4917 extra_size = tcbsize - TLS_TCB_SIZE; 4918 post_size = calculate_tls_post_size(tls_init_align); 4919 tls_block_size = tcbsize + post_size; 4920 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 4921 4922 return ((char *)tcb - pre_size - extra_size); 4923 } 4924 4925 /* 4926 * Allocate Static TLS using the Variant I method. 4927 * 4928 * For details on the layout, see lib/libc/gen/tls.c. 4929 * 4930 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as 4931 * it is based on tls_last_offset, and TLS offsets here are really TCB 4932 * offsets, whereas libc's tls_static_space is just the executable's static 4933 * TLS segment. 4934 */ 4935 void * 4936 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4937 { 4938 Obj_Entry *obj; 4939 char *tls_block; 4940 Elf_Addr *dtv, **tcb; 4941 Elf_Addr addr; 4942 Elf_Addr i; 4943 size_t extra_size, maxalign, post_size, pre_size, tls_block_size; 4944 size_t tls_init_align, tls_init_offset; 4945 4946 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4947 return (oldtcb); 4948 4949 assert(tcbsize >= TLS_TCB_SIZE); 4950 maxalign = MAX(tcbalign, tls_static_max_align); 4951 tls_init_align = MAX(obj_main->tlsalign, 1); 4952 4953 /* Compute fragmets sizes. */ 4954 extra_size = tcbsize - TLS_TCB_SIZE; 4955 post_size = calculate_tls_post_size(tls_init_align); 4956 tls_block_size = tcbsize + post_size; 4957 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 4958 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size; 4959 4960 /* Allocate whole TLS block */ 4961 tls_block = malloc_aligned(tls_block_size, maxalign, 0); 4962 tcb = (Elf_Addr **)(tls_block + pre_size + extra_size); 4963 4964 if (oldtcb != NULL) { 4965 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize), 4966 tls_static_space); 4967 free_aligned(get_tls_block_ptr(oldtcb, tcbsize)); 4968 4969 /* Adjust the DTV. */ 4970 dtv = tcb[0]; 4971 for (i = 0; i < dtv[1]; i++) { 4972 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4973 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4974 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tcb; 4975 } 4976 } 4977 } else { 4978 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4979 tcb[0] = dtv; 4980 dtv[0] = tls_dtv_generation; 4981 dtv[1] = tls_max_index; 4982 4983 for (obj = globallist_curr(objs); obj != NULL; 4984 obj = globallist_next(obj)) { 4985 if (obj->tlsoffset == 0) 4986 continue; 4987 tls_init_offset = obj->tlspoffset & (obj->tlsalign - 1); 4988 addr = (Elf_Addr)tcb + obj->tlsoffset; 4989 if (tls_init_offset > 0) 4990 memset((void *)addr, 0, tls_init_offset); 4991 if (obj->tlsinitsize > 0) { 4992 memcpy((void *)(addr + tls_init_offset), obj->tlsinit, 4993 obj->tlsinitsize); 4994 } 4995 if (obj->tlssize > obj->tlsinitsize) { 4996 memset((void *)(addr + tls_init_offset + obj->tlsinitsize), 4997 0, obj->tlssize - obj->tlsinitsize - tls_init_offset); 4998 } 4999 dtv[obj->tlsindex + 1] = addr; 5000 } 5001 } 5002 5003 return (tcb); 5004 } 5005 5006 void 5007 free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused) 5008 { 5009 Elf_Addr *dtv; 5010 Elf_Addr tlsstart, tlsend; 5011 size_t post_size; 5012 size_t dtvsize, i, tls_init_align; 5013 5014 assert(tcbsize >= TLS_TCB_SIZE); 5015 tls_init_align = MAX(obj_main->tlsalign, 1); 5016 5017 /* Compute fragments sizes. */ 5018 post_size = calculate_tls_post_size(tls_init_align); 5019 5020 tlsstart = (Elf_Addr)tcb + TLS_TCB_SIZE + post_size; 5021 tlsend = (Elf_Addr)tcb + tls_static_space; 5022 5023 dtv = *(Elf_Addr **)tcb; 5024 dtvsize = dtv[1]; 5025 for (i = 0; i < dtvsize; i++) { 5026 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 5027 free((void*)dtv[i+2]); 5028 } 5029 } 5030 free(dtv); 5031 free_aligned(get_tls_block_ptr(tcb, tcbsize)); 5032 } 5033 5034 #endif 5035 5036 #if defined(__i386__) || defined(__amd64__) 5037 5038 /* 5039 * Allocate Static TLS using the Variant II method. 5040 */ 5041 void * 5042 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 5043 { 5044 Obj_Entry *obj; 5045 size_t size, ralign; 5046 char *tls; 5047 Elf_Addr *dtv, *olddtv; 5048 Elf_Addr segbase, oldsegbase, addr; 5049 size_t i; 5050 5051 ralign = tcbalign; 5052 if (tls_static_max_align > ralign) 5053 ralign = tls_static_max_align; 5054 size = roundup(tls_static_space, ralign) + roundup(tcbsize, ralign); 5055 5056 assert(tcbsize >= 2*sizeof(Elf_Addr)); 5057 tls = malloc_aligned(size, ralign, 0 /* XXX */); 5058 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5059 5060 segbase = (Elf_Addr)(tls + roundup(tls_static_space, ralign)); 5061 ((Elf_Addr*)segbase)[0] = segbase; 5062 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 5063 5064 dtv[0] = tls_dtv_generation; 5065 dtv[1] = tls_max_index; 5066 5067 if (oldtls) { 5068 /* 5069 * Copy the static TLS block over whole. 5070 */ 5071 oldsegbase = (Elf_Addr) oldtls; 5072 memcpy((void *)(segbase - tls_static_space), 5073 (const void *)(oldsegbase - tls_static_space), 5074 tls_static_space); 5075 5076 /* 5077 * If any dynamic TLS blocks have been created tls_get_addr(), 5078 * move them over. 5079 */ 5080 olddtv = ((Elf_Addr**)oldsegbase)[1]; 5081 for (i = 0; i < olddtv[1]; i++) { 5082 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 5083 dtv[i+2] = olddtv[i+2]; 5084 olddtv[i+2] = 0; 5085 } 5086 } 5087 5088 /* 5089 * We assume that this block was the one we created with 5090 * allocate_initial_tls(). 5091 */ 5092 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 5093 } else { 5094 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 5095 if (obj->marker || obj->tlsoffset == 0) 5096 continue; 5097 addr = segbase - obj->tlsoffset; 5098 memset((void*)(addr + obj->tlsinitsize), 5099 0, obj->tlssize - obj->tlsinitsize); 5100 if (obj->tlsinit) { 5101 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 5102 obj->static_tls_copied = true; 5103 } 5104 dtv[obj->tlsindex + 1] = addr; 5105 } 5106 } 5107 5108 return (void*) segbase; 5109 } 5110 5111 void 5112 free_tls(void *tls, size_t tcbsize __unused, size_t tcbalign) 5113 { 5114 Elf_Addr* dtv; 5115 size_t size, ralign; 5116 int dtvsize, i; 5117 Elf_Addr tlsstart, tlsend; 5118 5119 /* 5120 * Figure out the size of the initial TLS block so that we can 5121 * find stuff which ___tls_get_addr() allocated dynamically. 5122 */ 5123 ralign = tcbalign; 5124 if (tls_static_max_align > ralign) 5125 ralign = tls_static_max_align; 5126 size = roundup(tls_static_space, ralign); 5127 5128 dtv = ((Elf_Addr**)tls)[1]; 5129 dtvsize = dtv[1]; 5130 tlsend = (Elf_Addr) tls; 5131 tlsstart = tlsend - size; 5132 for (i = 0; i < dtvsize; i++) { 5133 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 5134 free_aligned((void *)dtv[i + 2]); 5135 } 5136 } 5137 5138 free_aligned((void *)tlsstart); 5139 free((void*) dtv); 5140 } 5141 5142 #endif 5143 5144 /* 5145 * Allocate TLS block for module with given index. 5146 */ 5147 void * 5148 allocate_module_tls(int index) 5149 { 5150 Obj_Entry *obj; 5151 char *p; 5152 5153 TAILQ_FOREACH(obj, &obj_list, next) { 5154 if (obj->marker) 5155 continue; 5156 if (obj->tlsindex == index) 5157 break; 5158 } 5159 if (obj == NULL) { 5160 _rtld_error("Can't find module with TLS index %d", index); 5161 rtld_die(); 5162 } 5163 5164 p = malloc_aligned(obj->tlssize, obj->tlsalign, obj->tlspoffset); 5165 memcpy(p, obj->tlsinit, obj->tlsinitsize); 5166 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 5167 return (p); 5168 } 5169 5170 bool 5171 allocate_tls_offset(Obj_Entry *obj) 5172 { 5173 size_t off; 5174 5175 if (obj->tls_done) 5176 return true; 5177 5178 if (obj->tlssize == 0) { 5179 obj->tls_done = true; 5180 return true; 5181 } 5182 5183 if (tls_last_offset == 0) 5184 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign, 5185 obj->tlspoffset); 5186 else 5187 off = calculate_tls_offset(tls_last_offset, tls_last_size, 5188 obj->tlssize, obj->tlsalign, obj->tlspoffset); 5189 5190 /* 5191 * If we have already fixed the size of the static TLS block, we 5192 * must stay within that size. When allocating the static TLS, we 5193 * leave a small amount of space spare to be used for dynamically 5194 * loading modules which use static TLS. 5195 */ 5196 if (tls_static_space != 0) { 5197 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 5198 return false; 5199 } else if (obj->tlsalign > tls_static_max_align) { 5200 tls_static_max_align = obj->tlsalign; 5201 } 5202 5203 tls_last_offset = obj->tlsoffset = off; 5204 tls_last_size = obj->tlssize; 5205 obj->tls_done = true; 5206 5207 return true; 5208 } 5209 5210 void 5211 free_tls_offset(Obj_Entry *obj) 5212 { 5213 5214 /* 5215 * If we were the last thing to allocate out of the static TLS 5216 * block, we give our space back to the 'allocator'. This is a 5217 * simplistic workaround to allow libGL.so.1 to be loaded and 5218 * unloaded multiple times. 5219 */ 5220 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 5221 == calculate_tls_end(tls_last_offset, tls_last_size)) { 5222 tls_last_offset -= obj->tlssize; 5223 tls_last_size = 0; 5224 } 5225 } 5226 5227 void * 5228 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 5229 { 5230 void *ret; 5231 RtldLockState lockstate; 5232 5233 wlock_acquire(rtld_bind_lock, &lockstate); 5234 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 5235 tcbsize, tcbalign); 5236 lock_release(rtld_bind_lock, &lockstate); 5237 return (ret); 5238 } 5239 5240 void 5241 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 5242 { 5243 RtldLockState lockstate; 5244 5245 wlock_acquire(rtld_bind_lock, &lockstate); 5246 free_tls(tcb, tcbsize, tcbalign); 5247 lock_release(rtld_bind_lock, &lockstate); 5248 } 5249 5250 static void 5251 object_add_name(Obj_Entry *obj, const char *name) 5252 { 5253 Name_Entry *entry; 5254 size_t len; 5255 5256 len = strlen(name); 5257 entry = malloc(sizeof(Name_Entry) + len); 5258 5259 if (entry != NULL) { 5260 strcpy(entry->name, name); 5261 STAILQ_INSERT_TAIL(&obj->names, entry, link); 5262 } 5263 } 5264 5265 static int 5266 object_match_name(const Obj_Entry *obj, const char *name) 5267 { 5268 Name_Entry *entry; 5269 5270 STAILQ_FOREACH(entry, &obj->names, link) { 5271 if (strcmp(name, entry->name) == 0) 5272 return (1); 5273 } 5274 return (0); 5275 } 5276 5277 static Obj_Entry * 5278 locate_dependency(const Obj_Entry *obj, const char *name) 5279 { 5280 const Objlist_Entry *entry; 5281 const Needed_Entry *needed; 5282 5283 STAILQ_FOREACH(entry, &list_main, link) { 5284 if (object_match_name(entry->obj, name)) 5285 return entry->obj; 5286 } 5287 5288 for (needed = obj->needed; needed != NULL; needed = needed->next) { 5289 if (strcmp(obj->strtab + needed->name, name) == 0 || 5290 (needed->obj != NULL && object_match_name(needed->obj, name))) { 5291 /* 5292 * If there is DT_NEEDED for the name we are looking for, 5293 * we are all set. Note that object might not be found if 5294 * dependency was not loaded yet, so the function can 5295 * return NULL here. This is expected and handled 5296 * properly by the caller. 5297 */ 5298 return (needed->obj); 5299 } 5300 } 5301 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 5302 obj->path, name); 5303 rtld_die(); 5304 } 5305 5306 static int 5307 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 5308 const Elf_Vernaux *vna) 5309 { 5310 const Elf_Verdef *vd; 5311 const char *vername; 5312 5313 vername = refobj->strtab + vna->vna_name; 5314 vd = depobj->verdef; 5315 if (vd == NULL) { 5316 _rtld_error("%s: version %s required by %s not defined", 5317 depobj->path, vername, refobj->path); 5318 return (-1); 5319 } 5320 for (;;) { 5321 if (vd->vd_version != VER_DEF_CURRENT) { 5322 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5323 depobj->path, vd->vd_version); 5324 return (-1); 5325 } 5326 if (vna->vna_hash == vd->vd_hash) { 5327 const Elf_Verdaux *aux = (const Elf_Verdaux *) 5328 ((const char *)vd + vd->vd_aux); 5329 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 5330 return (0); 5331 } 5332 if (vd->vd_next == 0) 5333 break; 5334 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5335 } 5336 if (vna->vna_flags & VER_FLG_WEAK) 5337 return (0); 5338 _rtld_error("%s: version %s required by %s not found", 5339 depobj->path, vername, refobj->path); 5340 return (-1); 5341 } 5342 5343 static int 5344 rtld_verify_object_versions(Obj_Entry *obj) 5345 { 5346 const Elf_Verneed *vn; 5347 const Elf_Verdef *vd; 5348 const Elf_Verdaux *vda; 5349 const Elf_Vernaux *vna; 5350 const Obj_Entry *depobj; 5351 int maxvernum, vernum; 5352 5353 if (obj->ver_checked) 5354 return (0); 5355 obj->ver_checked = true; 5356 5357 maxvernum = 0; 5358 /* 5359 * Walk over defined and required version records and figure out 5360 * max index used by any of them. Do very basic sanity checking 5361 * while there. 5362 */ 5363 vn = obj->verneed; 5364 while (vn != NULL) { 5365 if (vn->vn_version != VER_NEED_CURRENT) { 5366 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 5367 obj->path, vn->vn_version); 5368 return (-1); 5369 } 5370 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5371 for (;;) { 5372 vernum = VER_NEED_IDX(vna->vna_other); 5373 if (vernum > maxvernum) 5374 maxvernum = vernum; 5375 if (vna->vna_next == 0) 5376 break; 5377 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5378 } 5379 if (vn->vn_next == 0) 5380 break; 5381 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5382 } 5383 5384 vd = obj->verdef; 5385 while (vd != NULL) { 5386 if (vd->vd_version != VER_DEF_CURRENT) { 5387 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5388 obj->path, vd->vd_version); 5389 return (-1); 5390 } 5391 vernum = VER_DEF_IDX(vd->vd_ndx); 5392 if (vernum > maxvernum) 5393 maxvernum = vernum; 5394 if (vd->vd_next == 0) 5395 break; 5396 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5397 } 5398 5399 if (maxvernum == 0) 5400 return (0); 5401 5402 /* 5403 * Store version information in array indexable by version index. 5404 * Verify that object version requirements are satisfied along the 5405 * way. 5406 */ 5407 obj->vernum = maxvernum + 1; 5408 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 5409 5410 vd = obj->verdef; 5411 while (vd != NULL) { 5412 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 5413 vernum = VER_DEF_IDX(vd->vd_ndx); 5414 assert(vernum <= maxvernum); 5415 vda = (const Elf_Verdaux *)((const char *)vd + vd->vd_aux); 5416 obj->vertab[vernum].hash = vd->vd_hash; 5417 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 5418 obj->vertab[vernum].file = NULL; 5419 obj->vertab[vernum].flags = 0; 5420 } 5421 if (vd->vd_next == 0) 5422 break; 5423 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5424 } 5425 5426 vn = obj->verneed; 5427 while (vn != NULL) { 5428 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 5429 if (depobj == NULL) 5430 return (-1); 5431 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5432 for (;;) { 5433 if (check_object_provided_version(obj, depobj, vna)) 5434 return (-1); 5435 vernum = VER_NEED_IDX(vna->vna_other); 5436 assert(vernum <= maxvernum); 5437 obj->vertab[vernum].hash = vna->vna_hash; 5438 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 5439 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 5440 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 5441 VER_INFO_HIDDEN : 0; 5442 if (vna->vna_next == 0) 5443 break; 5444 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5445 } 5446 if (vn->vn_next == 0) 5447 break; 5448 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5449 } 5450 return 0; 5451 } 5452 5453 static int 5454 rtld_verify_versions(const Objlist *objlist) 5455 { 5456 Objlist_Entry *entry; 5457 int rc; 5458 5459 rc = 0; 5460 STAILQ_FOREACH(entry, objlist, link) { 5461 /* 5462 * Skip dummy objects or objects that have their version requirements 5463 * already checked. 5464 */ 5465 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 5466 continue; 5467 if (rtld_verify_object_versions(entry->obj) == -1) { 5468 rc = -1; 5469 if (ld_tracing == NULL) 5470 break; 5471 } 5472 } 5473 if (rc == 0 || ld_tracing != NULL) 5474 rc = rtld_verify_object_versions(&obj_rtld); 5475 return rc; 5476 } 5477 5478 const Ver_Entry * 5479 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 5480 { 5481 Elf_Versym vernum; 5482 5483 if (obj->vertab) { 5484 vernum = VER_NDX(obj->versyms[symnum]); 5485 if (vernum >= obj->vernum) { 5486 _rtld_error("%s: symbol %s has wrong verneed value %d", 5487 obj->path, obj->strtab + symnum, vernum); 5488 } else if (obj->vertab[vernum].hash != 0) { 5489 return &obj->vertab[vernum]; 5490 } 5491 } 5492 return NULL; 5493 } 5494 5495 int 5496 _rtld_get_stack_prot(void) 5497 { 5498 5499 return (stack_prot); 5500 } 5501 5502 int 5503 _rtld_is_dlopened(void *arg) 5504 { 5505 Obj_Entry *obj; 5506 RtldLockState lockstate; 5507 int res; 5508 5509 rlock_acquire(rtld_bind_lock, &lockstate); 5510 obj = dlcheck(arg); 5511 if (obj == NULL) 5512 obj = obj_from_addr(arg); 5513 if (obj == NULL) { 5514 _rtld_error("No shared object contains address"); 5515 lock_release(rtld_bind_lock, &lockstate); 5516 return (-1); 5517 } 5518 res = obj->dlopened ? 1 : 0; 5519 lock_release(rtld_bind_lock, &lockstate); 5520 return (res); 5521 } 5522 5523 static int 5524 obj_remap_relro(Obj_Entry *obj, int prot) 5525 { 5526 5527 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size, 5528 prot) == -1) { 5529 _rtld_error("%s: Cannot set relro protection to %#x: %s", 5530 obj->path, prot, rtld_strerror(errno)); 5531 return (-1); 5532 } 5533 return (0); 5534 } 5535 5536 static int 5537 obj_disable_relro(Obj_Entry *obj) 5538 { 5539 5540 return (obj_remap_relro(obj, PROT_READ | PROT_WRITE)); 5541 } 5542 5543 static int 5544 obj_enforce_relro(Obj_Entry *obj) 5545 { 5546 5547 return (obj_remap_relro(obj, PROT_READ)); 5548 } 5549 5550 static void 5551 map_stacks_exec(RtldLockState *lockstate) 5552 { 5553 void (*thr_map_stacks_exec)(void); 5554 5555 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5556 return; 5557 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5558 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5559 if (thr_map_stacks_exec != NULL) { 5560 stack_prot |= PROT_EXEC; 5561 thr_map_stacks_exec(); 5562 } 5563 } 5564 5565 static void 5566 distribute_static_tls(Objlist *list, RtldLockState *lockstate) 5567 { 5568 Objlist_Entry *elm; 5569 Obj_Entry *obj; 5570 void (*distrib)(size_t, void *, size_t, size_t); 5571 5572 distrib = (void (*)(size_t, void *, size_t, size_t))(uintptr_t) 5573 get_program_var_addr("__pthread_distribute_static_tls", lockstate); 5574 if (distrib == NULL) 5575 return; 5576 STAILQ_FOREACH(elm, list, link) { 5577 obj = elm->obj; 5578 if (obj->marker || !obj->tls_done || obj->static_tls_copied) 5579 continue; 5580 distrib(obj->tlsoffset, obj->tlsinit, obj->tlsinitsize, 5581 obj->tlssize); 5582 obj->static_tls_copied = true; 5583 } 5584 } 5585 5586 void 5587 symlook_init(SymLook *dst, const char *name) 5588 { 5589 5590 bzero(dst, sizeof(*dst)); 5591 dst->name = name; 5592 dst->hash = elf_hash(name); 5593 dst->hash_gnu = gnu_hash(name); 5594 } 5595 5596 static void 5597 symlook_init_from_req(SymLook *dst, const SymLook *src) 5598 { 5599 5600 dst->name = src->name; 5601 dst->hash = src->hash; 5602 dst->hash_gnu = src->hash_gnu; 5603 dst->ventry = src->ventry; 5604 dst->flags = src->flags; 5605 dst->defobj_out = NULL; 5606 dst->sym_out = NULL; 5607 dst->lockstate = src->lockstate; 5608 } 5609 5610 static int 5611 open_binary_fd(const char *argv0, bool search_in_path, 5612 const char **binpath_res) 5613 { 5614 char *binpath, *pathenv, *pe, *res1; 5615 const char *res; 5616 int fd; 5617 5618 binpath = NULL; 5619 res = NULL; 5620 if (search_in_path && strchr(argv0, '/') == NULL) { 5621 binpath = xmalloc(PATH_MAX); 5622 pathenv = getenv("PATH"); 5623 if (pathenv == NULL) { 5624 _rtld_error("-p and no PATH environment variable"); 5625 rtld_die(); 5626 } 5627 pathenv = strdup(pathenv); 5628 if (pathenv == NULL) { 5629 _rtld_error("Cannot allocate memory"); 5630 rtld_die(); 5631 } 5632 fd = -1; 5633 errno = ENOENT; 5634 while ((pe = strsep(&pathenv, ":")) != NULL) { 5635 if (strlcpy(binpath, pe, PATH_MAX) >= PATH_MAX) 5636 continue; 5637 if (binpath[0] != '\0' && 5638 strlcat(binpath, "/", PATH_MAX) >= PATH_MAX) 5639 continue; 5640 if (strlcat(binpath, argv0, PATH_MAX) >= PATH_MAX) 5641 continue; 5642 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY); 5643 if (fd != -1 || errno != ENOENT) { 5644 res = binpath; 5645 break; 5646 } 5647 } 5648 free(pathenv); 5649 } else { 5650 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY); 5651 res = argv0; 5652 } 5653 5654 if (fd == -1) { 5655 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno)); 5656 rtld_die(); 5657 } 5658 if (res != NULL && res[0] != '/') { 5659 res1 = xmalloc(PATH_MAX); 5660 if (realpath(res, res1) != NULL) { 5661 if (res != argv0) 5662 free(__DECONST(char *, res)); 5663 res = res1; 5664 } else { 5665 free(res1); 5666 } 5667 } 5668 *binpath_res = res; 5669 return (fd); 5670 } 5671 5672 /* 5673 * Parse a set of command-line arguments. 5674 */ 5675 static int 5676 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp, 5677 const char **argv0) 5678 { 5679 const char *arg; 5680 char machine[64]; 5681 size_t sz; 5682 int arglen, fd, i, j, mib[2]; 5683 char opt; 5684 bool seen_b, seen_f; 5685 5686 dbg("Parsing command-line arguments"); 5687 *use_pathp = false; 5688 *fdp = -1; 5689 seen_b = seen_f = false; 5690 5691 for (i = 1; i < argc; i++ ) { 5692 arg = argv[i]; 5693 dbg("argv[%d]: '%s'", i, arg); 5694 5695 /* 5696 * rtld arguments end with an explicit "--" or with the first 5697 * non-prefixed argument. 5698 */ 5699 if (strcmp(arg, "--") == 0) { 5700 i++; 5701 break; 5702 } 5703 if (arg[0] != '-') 5704 break; 5705 5706 /* 5707 * All other arguments are single-character options that can 5708 * be combined, so we need to search through `arg` for them. 5709 */ 5710 arglen = strlen(arg); 5711 for (j = 1; j < arglen; j++) { 5712 opt = arg[j]; 5713 if (opt == 'h') { 5714 print_usage(argv[0]); 5715 _exit(0); 5716 } else if (opt == 'b') { 5717 if (seen_f) { 5718 _rtld_error("Both -b and -f specified"); 5719 rtld_die(); 5720 } 5721 i++; 5722 *argv0 = argv[i]; 5723 seen_b = true; 5724 break; 5725 } else if (opt == 'f') { 5726 if (seen_b) { 5727 _rtld_error("Both -b and -f specified"); 5728 rtld_die(); 5729 } 5730 5731 /* 5732 * -f XX can be used to specify a 5733 * descriptor for the binary named at 5734 * the command line (i.e., the later 5735 * argument will specify the process 5736 * name but the descriptor is what 5737 * will actually be executed). 5738 * 5739 * -f must be the last option in, e.g., -abcf. 5740 */ 5741 if (j != arglen - 1) { 5742 _rtld_error("Invalid options: %s", arg); 5743 rtld_die(); 5744 } 5745 i++; 5746 fd = parse_integer(argv[i]); 5747 if (fd == -1) { 5748 _rtld_error( 5749 "Invalid file descriptor: '%s'", 5750 argv[i]); 5751 rtld_die(); 5752 } 5753 *fdp = fd; 5754 seen_f = true; 5755 break; 5756 } else if (opt == 'p') { 5757 *use_pathp = true; 5758 } else if (opt == 'v') { 5759 machine[0] = '\0'; 5760 mib[0] = CTL_HW; 5761 mib[1] = HW_MACHINE; 5762 sz = sizeof(machine); 5763 sysctl(mib, nitems(mib), machine, &sz, NULL, 0); 5764 rtld_printf( 5765 "FreeBSD ld-elf.so.1 %s\n" 5766 "FreeBSD_version %d\n" 5767 "Default lib path %s\n" 5768 "Env prefix %s\n" 5769 "Hint file %s\n" 5770 "libmap file %s\n", 5771 machine, 5772 __FreeBSD_version, ld_standard_library_path, 5773 ld_env_prefix, ld_elf_hints_default, 5774 ld_path_libmap_conf); 5775 _exit(0); 5776 } else { 5777 _rtld_error("Invalid argument: '%s'", arg); 5778 print_usage(argv[0]); 5779 rtld_die(); 5780 } 5781 } 5782 } 5783 5784 if (!seen_b) 5785 *argv0 = argv[i]; 5786 return (i); 5787 } 5788 5789 /* 5790 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 5791 */ 5792 static int 5793 parse_integer(const char *str) 5794 { 5795 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 5796 const char *orig; 5797 int n; 5798 char c; 5799 5800 orig = str; 5801 n = 0; 5802 for (c = *str; c != '\0'; c = *++str) { 5803 if (c < '0' || c > '9') 5804 return (-1); 5805 5806 n *= RADIX; 5807 n += c - '0'; 5808 } 5809 5810 /* Make sure we actually parsed something. */ 5811 if (str == orig) 5812 return (-1); 5813 return (n); 5814 } 5815 5816 static void 5817 print_usage(const char *argv0) 5818 { 5819 5820 rtld_printf( 5821 "Usage: %s [-h] [-b <exe>] [-f <FD>] [-p] [--] <binary> [<args>]\n" 5822 "\n" 5823 "Options:\n" 5824 " -h Display this help message\n" 5825 " -b <exe> Execute <exe> instead of <binary>, arg0 is <binary>\n" 5826 " -f <FD> Execute <FD> instead of searching for <binary>\n" 5827 " -p Search in PATH for named binary\n" 5828 " -v Display identification information\n" 5829 " -- End of RTLD options\n" 5830 " <binary> Name of process to execute\n" 5831 " <args> Arguments to the executed process\n", argv0); 5832 } 5833 5834 /* 5835 * Overrides for libc_pic-provided functions. 5836 */ 5837 5838 int 5839 __getosreldate(void) 5840 { 5841 size_t len; 5842 int oid[2]; 5843 int error, osrel; 5844 5845 if (osreldate != 0) 5846 return (osreldate); 5847 5848 oid[0] = CTL_KERN; 5849 oid[1] = KERN_OSRELDATE; 5850 osrel = 0; 5851 len = sizeof(osrel); 5852 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 5853 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 5854 osreldate = osrel; 5855 return (osreldate); 5856 } 5857 const char * 5858 rtld_strerror(int errnum) 5859 { 5860 5861 if (errnum < 0 || errnum >= sys_nerr) 5862 return ("Unknown error"); 5863 return (sys_errlist[errnum]); 5864 } 5865 5866 /* malloc */ 5867 void * 5868 malloc(size_t nbytes) 5869 { 5870 5871 return (__crt_malloc(nbytes)); 5872 } 5873 5874 void * 5875 calloc(size_t num, size_t size) 5876 { 5877 5878 return (__crt_calloc(num, size)); 5879 } 5880 5881 void 5882 free(void *cp) 5883 { 5884 5885 __crt_free(cp); 5886 } 5887 5888 void * 5889 realloc(void *cp, size_t nbytes) 5890 { 5891 5892 return (__crt_realloc(cp, nbytes)); 5893 } 5894 5895 extern int _rtld_version__FreeBSD_version __exported; 5896 int _rtld_version__FreeBSD_version = __FreeBSD_version; 5897 5898 extern char _rtld_version_laddr_offset __exported; 5899 char _rtld_version_laddr_offset; 5900