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 "rtld_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 struct dlerror_save { 85 int seen; 86 char *msg; 87 }; 88 89 /* 90 * Function declarations. 91 */ 92 static const char *basename(const char *); 93 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 94 const Elf_Dyn **, const Elf_Dyn **); 95 static bool digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *, 96 const Elf_Dyn *); 97 static bool digest_dynamic(Obj_Entry *, int); 98 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 99 static void distribute_static_tls(Objlist *, RtldLockState *); 100 static Obj_Entry *dlcheck(void *); 101 static int dlclose_locked(void *, RtldLockState *); 102 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, 103 int lo_flags, int mode, RtldLockState *lockstate); 104 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 105 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 106 static bool donelist_check(DoneList *, const Obj_Entry *); 107 static void dump_auxv(Elf_Auxinfo **aux_info); 108 static void errmsg_restore(struct dlerror_save *); 109 static struct dlerror_save *errmsg_save(void); 110 static void *fill_search_info(const char *, size_t, void *); 111 static char *find_library(const char *, const Obj_Entry *, int *); 112 static const char *gethints(bool); 113 static void hold_object(Obj_Entry *); 114 static void unhold_object(Obj_Entry *); 115 static void init_dag(Obj_Entry *); 116 static void init_marker(Obj_Entry *); 117 static void init_pagesizes(Elf_Auxinfo **aux_info); 118 static void init_rtld(caddr_t, Elf_Auxinfo **); 119 static void initlist_add_neededs(Needed_Entry *, Objlist *); 120 static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *); 121 static int initlist_objects_ifunc(Objlist *, bool, int, RtldLockState *); 122 static void linkmap_add(Obj_Entry *); 123 static void linkmap_delete(Obj_Entry *); 124 static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 125 static void unload_filtees(Obj_Entry *, RtldLockState *); 126 static int load_needed_objects(Obj_Entry *, int); 127 static int load_preload_objects(const char *, bool); 128 static int load_kpreload(const void *addr); 129 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 130 static void map_stacks_exec(RtldLockState *); 131 static int obj_disable_relro(Obj_Entry *); 132 static int obj_enforce_relro(Obj_Entry *); 133 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 134 static void objlist_call_init(Objlist *, RtldLockState *); 135 static void objlist_clear(Objlist *); 136 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 137 static void objlist_init(Objlist *); 138 static void objlist_push_head(Objlist *, Obj_Entry *); 139 static void objlist_push_tail(Objlist *, Obj_Entry *); 140 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 141 static void objlist_remove(Objlist *, Obj_Entry *); 142 static int open_binary_fd(const char *argv0, bool search_in_path, 143 const char **binpath_res); 144 static int parse_args(char* argv[], int argc, bool *use_pathp, int *fdp, 145 const char **argv0, bool *dir_ignore); 146 static int parse_integer(const char *); 147 static void *path_enumerate(const char *, path_enum_proc, const char *, void *); 148 static void print_usage(const char *argv0); 149 static void release_object(Obj_Entry *); 150 static int relocate_object_dag(Obj_Entry *root, bool bind_now, 151 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 152 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 153 int flags, RtldLockState *lockstate); 154 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 155 RtldLockState *); 156 static int resolve_object_ifunc(Obj_Entry *, bool, int, RtldLockState *); 157 static int rtld_dirname(const char *, char *); 158 static int rtld_dirname_abs(const char *, char *); 159 static void *rtld_dlopen(const char *name, int fd, int mode); 160 static void rtld_exit(void); 161 static void rtld_nop_exit(void); 162 static char *search_library_path(const char *, const char *, const char *, 163 int *); 164 static char *search_library_pathfds(const char *, const char *, int *); 165 static const void **get_program_var_addr(const char *, RtldLockState *); 166 static void set_program_var(const char *, const void *); 167 static int symlook_default(SymLook *, const Obj_Entry *refobj); 168 static int symlook_global(SymLook *, DoneList *); 169 static void symlook_init_from_req(SymLook *, const SymLook *); 170 static int symlook_list(SymLook *, const Objlist *, DoneList *); 171 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 172 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 173 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 174 static void *tls_get_addr_slow(Elf_Addr **, int, size_t, bool) __noinline; 175 static void trace_loaded_objects(Obj_Entry *); 176 static void unlink_object(Obj_Entry *); 177 static void unload_object(Obj_Entry *, RtldLockState *lockstate); 178 static void unref_dag(Obj_Entry *); 179 static void ref_dag(Obj_Entry *); 180 static char *origin_subst_one(Obj_Entry *, char *, const char *, 181 const char *, bool); 182 static char *origin_subst(Obj_Entry *, const char *); 183 static bool obj_resolve_origin(Obj_Entry *obj); 184 static void preinit_main(void); 185 static int rtld_verify_versions(const Objlist *); 186 static int rtld_verify_object_versions(Obj_Entry *); 187 static void object_add_name(Obj_Entry *, const char *); 188 static int object_match_name(const Obj_Entry *, const char *); 189 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 190 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 191 struct dl_phdr_info *phdr_info); 192 static uint32_t gnu_hash(const char *); 193 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 194 const unsigned long); 195 196 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported; 197 void _r_debug_postinit(struct link_map *) __noinline __exported; 198 199 int __sys_openat(int, const char *, int, ...); 200 201 /* 202 * Data declarations. 203 */ 204 struct r_debug r_debug __exported; /* for GDB; */ 205 static bool libmap_disable; /* Disable libmap */ 206 static bool ld_loadfltr; /* Immediate filters processing */ 207 static const char *libmap_override;/* Maps to use in addition to libmap.conf */ 208 static bool trust; /* False for setuid and setgid programs */ 209 static bool dangerous_ld_env; /* True if environment variables have been 210 used to affect the libraries loaded */ 211 bool ld_bind_not; /* Disable PLT update */ 212 static const char *ld_bind_now; /* Environment variable for immediate binding */ 213 static const char *ld_debug; /* Environment variable for debugging */ 214 static bool ld_dynamic_weak = true; /* True if non-weak definition overrides 215 weak definition */ 216 static const char *ld_library_path;/* Environment variable for search path */ 217 static const char *ld_library_dirs;/* Environment variable for library descriptors */ 218 static const char *ld_preload; /* Environment variable for libraries to 219 load first */ 220 static const char *ld_preload_fds;/* Environment variable for libraries represented by 221 descriptors */ 222 static const char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 223 static const char *ld_tracing; /* Called from ldd to print libs */ 224 static const char *ld_utrace; /* Use utrace() to log events. */ 225 static struct obj_entry_q obj_list; /* Queue of all loaded objects */ 226 static Obj_Entry *obj_main; /* The main program shared object */ 227 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 228 static unsigned int obj_count; /* Number of objects in obj_list */ 229 static unsigned int obj_loads; /* Number of loads of objects (gen count) */ 230 231 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 232 STAILQ_HEAD_INITIALIZER(list_global); 233 static Objlist list_main = /* Objects loaded at program startup */ 234 STAILQ_HEAD_INITIALIZER(list_main); 235 static Objlist list_fini = /* Objects needing fini() calls */ 236 STAILQ_HEAD_INITIALIZER(list_fini); 237 238 Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 239 240 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 241 242 extern Elf_Dyn _DYNAMIC; 243 #pragma weak _DYNAMIC 244 245 int dlclose(void *) __exported; 246 char *dlerror(void) __exported; 247 void *dlopen(const char *, int) __exported; 248 void *fdlopen(int, int) __exported; 249 void *dlsym(void *, const char *) __exported; 250 dlfunc_t dlfunc(void *, const char *) __exported; 251 void *dlvsym(void *, const char *, const char *) __exported; 252 int dladdr(const void *, Dl_info *) __exported; 253 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *), 254 void (*)(void *), void (*)(void *), void (*)(void *)) __exported; 255 int dlinfo(void *, int , void *) __exported; 256 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported; 257 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported; 258 int _rtld_get_stack_prot(void) __exported; 259 int _rtld_is_dlopened(void *) __exported; 260 void _rtld_error(const char *, ...) __exported; 261 262 /* Only here to fix -Wmissing-prototypes warnings */ 263 int __getosreldate(void); 264 func_ptr_type _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp); 265 Elf_Addr _rtld_bind(Obj_Entry *obj, Elf_Size reloff); 266 267 268 int npagesizes; 269 static int osreldate; 270 size_t *pagesizes; 271 272 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 273 static int max_stack_flags; 274 275 /* 276 * Global declarations normally provided by crt1. The dynamic linker is 277 * not built with crt1, so we have to provide them ourselves. 278 */ 279 char *__progname; 280 char **environ; 281 282 /* 283 * Used to pass argc, argv to init functions. 284 */ 285 int main_argc; 286 char **main_argv; 287 288 /* 289 * Globals to control TLS allocation. 290 */ 291 size_t tls_last_offset; /* Static TLS offset of last module */ 292 size_t tls_last_size; /* Static TLS size of last module */ 293 size_t tls_static_space; /* Static TLS space allocated */ 294 static size_t tls_static_max_align; 295 Elf_Addr tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 296 int tls_max_index = 1; /* Largest module index allocated */ 297 298 static bool ld_library_path_rpath = false; 299 bool ld_fast_sigblock = false; 300 301 /* 302 * Globals for path names, and such 303 */ 304 const char *ld_elf_hints_default = _PATH_ELF_HINTS; 305 const char *ld_path_libmap_conf = _PATH_LIBMAP_CONF; 306 const char *ld_path_rtld = _PATH_RTLD; 307 const char *ld_standard_library_path = STANDARD_LIBRARY_PATH; 308 const char *ld_env_prefix = LD_; 309 310 static void (*rtld_exit_ptr)(void); 311 312 /* 313 * Fill in a DoneList with an allocation large enough to hold all of 314 * the currently-loaded objects. Keep this as a macro since it calls 315 * alloca and we want that to occur within the scope of the caller. 316 */ 317 #define donelist_init(dlp) \ 318 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 319 assert((dlp)->objs != NULL), \ 320 (dlp)->num_alloc = obj_count, \ 321 (dlp)->num_used = 0) 322 323 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 324 if (ld_utrace != NULL) \ 325 ld_utrace_log(e, h, mb, ms, r, n); \ 326 } while (0) 327 328 static void 329 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 330 int refcnt, const char *name) 331 { 332 struct utrace_rtld ut; 333 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG; 334 335 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig)); 336 ut.event = event; 337 ut.handle = handle; 338 ut.mapbase = mapbase; 339 ut.mapsize = mapsize; 340 ut.refcnt = refcnt; 341 bzero(ut.name, sizeof(ut.name)); 342 if (name) 343 strlcpy(ut.name, name, sizeof(ut.name)); 344 utrace(&ut, sizeof(ut)); 345 } 346 347 enum { 348 LD_BIND_NOW = 0, 349 LD_PRELOAD, 350 LD_LIBMAP, 351 LD_LIBRARY_PATH, 352 LD_LIBRARY_PATH_FDS, 353 LD_LIBMAP_DISABLE, 354 LD_BIND_NOT, 355 LD_DEBUG, 356 LD_ELF_HINTS_PATH, 357 LD_LOADFLTR, 358 LD_LIBRARY_PATH_RPATH, 359 LD_PRELOAD_FDS, 360 LD_DYNAMIC_WEAK, 361 LD_TRACE_LOADED_OBJECTS, 362 LD_UTRACE, 363 LD_DUMP_REL_PRE, 364 LD_DUMP_REL_POST, 365 LD_TRACE_LOADED_OBJECTS_PROGNAME, 366 LD_TRACE_LOADED_OBJECTS_FMT1, 367 LD_TRACE_LOADED_OBJECTS_FMT2, 368 LD_TRACE_LOADED_OBJECTS_ALL, 369 LD_SHOW_AUXV, 370 }; 371 372 struct ld_env_var_desc { 373 const char * const n; 374 const char *val; 375 const bool unsecure; 376 }; 377 #define LD_ENV_DESC(var, unsec) \ 378 [LD_##var] = { .n = #var, .unsecure = unsec } 379 380 static struct ld_env_var_desc ld_env_vars[] = { 381 LD_ENV_DESC(BIND_NOW, false), 382 LD_ENV_DESC(PRELOAD, true), 383 LD_ENV_DESC(LIBMAP, true), 384 LD_ENV_DESC(LIBRARY_PATH, true), 385 LD_ENV_DESC(LIBRARY_PATH_FDS, true), 386 LD_ENV_DESC(LIBMAP_DISABLE, true), 387 LD_ENV_DESC(BIND_NOT, true), 388 LD_ENV_DESC(DEBUG, true), 389 LD_ENV_DESC(ELF_HINTS_PATH, true), 390 LD_ENV_DESC(LOADFLTR, true), 391 LD_ENV_DESC(LIBRARY_PATH_RPATH, true), 392 LD_ENV_DESC(PRELOAD_FDS, true), 393 LD_ENV_DESC(DYNAMIC_WEAK, true), 394 LD_ENV_DESC(TRACE_LOADED_OBJECTS, false), 395 LD_ENV_DESC(UTRACE, false), 396 LD_ENV_DESC(DUMP_REL_PRE, false), 397 LD_ENV_DESC(DUMP_REL_POST, false), 398 LD_ENV_DESC(TRACE_LOADED_OBJECTS_PROGNAME, false), 399 LD_ENV_DESC(TRACE_LOADED_OBJECTS_FMT1, false), 400 LD_ENV_DESC(TRACE_LOADED_OBJECTS_FMT2, false), 401 LD_ENV_DESC(TRACE_LOADED_OBJECTS_ALL, false), 402 LD_ENV_DESC(SHOW_AUXV, false), 403 }; 404 405 static const char * 406 ld_get_env_var(int idx) 407 { 408 return (ld_env_vars[idx].val); 409 } 410 411 static const char * 412 rtld_get_env_val(char **env, const char *name, size_t name_len) 413 { 414 char **m, *n, *v; 415 416 for (m = env; *m != NULL; m++) { 417 n = *m; 418 v = strchr(n, '='); 419 if (v == NULL) { 420 /* corrupt environment? */ 421 continue; 422 } 423 if (v - n == (ptrdiff_t)name_len && 424 strncmp(name, n, name_len) == 0) 425 return (v + 1); 426 } 427 return (NULL); 428 } 429 430 static void 431 rtld_init_env_vars_for_prefix(char **env, const char *env_prefix) 432 { 433 struct ld_env_var_desc *lvd; 434 size_t prefix_len, nlen; 435 char **m, *n, *v; 436 int i; 437 438 prefix_len = strlen(env_prefix); 439 for (m = env; *m != NULL; m++) { 440 n = *m; 441 if (strncmp(env_prefix, n, prefix_len) != 0) { 442 /* Not a rtld environment variable. */ 443 continue; 444 } 445 n += prefix_len; 446 v = strchr(n, '='); 447 if (v == NULL) { 448 /* corrupt environment? */ 449 continue; 450 } 451 for (i = 0; i < (int)nitems(ld_env_vars); i++) { 452 lvd = &ld_env_vars[i]; 453 if (lvd->val != NULL) { 454 /* Saw higher-priority variable name already. */ 455 continue; 456 } 457 nlen = strlen(lvd->n); 458 if (v - n == (ptrdiff_t)nlen && 459 strncmp(lvd->n, n, nlen) == 0) { 460 lvd->val = v + 1; 461 break; 462 } 463 } 464 } 465 } 466 467 static void 468 rtld_init_env_vars(char **env) 469 { 470 rtld_init_env_vars_for_prefix(env, ld_env_prefix); 471 } 472 473 static void 474 set_ld_elf_hints_path(void) 475 { 476 if (ld_elf_hints_path == NULL || strlen(ld_elf_hints_path) == 0) 477 ld_elf_hints_path = ld_elf_hints_default; 478 } 479 480 /* 481 * Main entry point for dynamic linking. The first argument is the 482 * stack pointer. The stack is expected to be laid out as described 483 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 484 * Specifically, the stack pointer points to a word containing 485 * ARGC. Following that in the stack is a null-terminated sequence 486 * of pointers to argument strings. Then comes a null-terminated 487 * sequence of pointers to environment strings. Finally, there is a 488 * sequence of "auxiliary vector" entries. 489 * 490 * The second argument points to a place to store the dynamic linker's 491 * exit procedure pointer and the third to a place to store the main 492 * program's object. 493 * 494 * The return value is the main program's entry point. 495 */ 496 func_ptr_type 497 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 498 { 499 Elf_Auxinfo *aux, *auxp, *auxpf, *aux_info[AT_COUNT]; 500 Objlist_Entry *entry; 501 Obj_Entry *last_interposer, *obj, *preload_tail; 502 const Elf_Phdr *phdr; 503 Objlist initlist; 504 RtldLockState lockstate; 505 struct stat st; 506 Elf_Addr *argcp; 507 char **argv, **env, **envp, *kexecpath; 508 const char *argv0, *binpath, *library_path_rpath; 509 struct ld_env_var_desc *lvd; 510 caddr_t imgentry; 511 char buf[MAXPATHLEN]; 512 int argc, fd, i, mib[4], old_osrel, osrel, phnum, rtld_argc; 513 size_t sz; 514 #ifdef __powerpc__ 515 int old_auxv_format = 1; 516 #endif 517 bool dir_enable, dir_ignore, direct_exec, explicit_fd, search_in_path; 518 519 /* 520 * On entry, the dynamic linker itself has not been relocated yet. 521 * Be very careful not to reference any global data until after 522 * init_rtld has returned. It is OK to reference file-scope statics 523 * and string constants, and to call static and global functions. 524 */ 525 526 /* Find the auxiliary vector on the stack. */ 527 argcp = sp; 528 argc = *sp++; 529 argv = (char **) sp; 530 sp += argc + 1; /* Skip over arguments and NULL terminator */ 531 env = (char **) sp; 532 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 533 ; 534 aux = (Elf_Auxinfo *) sp; 535 536 /* Digest the auxiliary vector. */ 537 for (i = 0; i < AT_COUNT; i++) 538 aux_info[i] = NULL; 539 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 540 if (auxp->a_type < AT_COUNT) 541 aux_info[auxp->a_type] = auxp; 542 #ifdef __powerpc__ 543 if (auxp->a_type == 23) /* AT_STACKPROT */ 544 old_auxv_format = 0; 545 #endif 546 } 547 548 #ifdef __powerpc__ 549 if (old_auxv_format) { 550 /* Remap from old-style auxv numbers. */ 551 aux_info[23] = aux_info[21]; /* AT_STACKPROT */ 552 aux_info[21] = aux_info[19]; /* AT_PAGESIZESLEN */ 553 aux_info[19] = aux_info[17]; /* AT_NCPUS */ 554 aux_info[17] = aux_info[15]; /* AT_CANARYLEN */ 555 aux_info[15] = aux_info[13]; /* AT_EXECPATH */ 556 aux_info[13] = NULL; /* AT_GID */ 557 558 aux_info[20] = aux_info[18]; /* AT_PAGESIZES */ 559 aux_info[18] = aux_info[16]; /* AT_OSRELDATE */ 560 aux_info[16] = aux_info[14]; /* AT_CANARY */ 561 aux_info[14] = NULL; /* AT_EGID */ 562 } 563 #endif 564 565 /* Initialize and relocate ourselves. */ 566 assert(aux_info[AT_BASE] != NULL); 567 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 568 569 dlerror_dflt_init(); 570 571 __progname = obj_rtld.path; 572 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 573 environ = env; 574 main_argc = argc; 575 main_argv = argv; 576 577 if (aux_info[AT_BSDFLAGS] != NULL && 578 (aux_info[AT_BSDFLAGS]->a_un.a_val & ELF_BSDF_SIGFASTBLK) != 0) 579 ld_fast_sigblock = true; 580 581 trust = !issetugid(); 582 direct_exec = false; 583 584 md_abi_variant_hook(aux_info); 585 rtld_init_env_vars(env); 586 587 fd = -1; 588 if (aux_info[AT_EXECFD] != NULL) { 589 fd = aux_info[AT_EXECFD]->a_un.a_val; 590 } else { 591 assert(aux_info[AT_PHDR] != NULL); 592 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr; 593 if (phdr == obj_rtld.phdr) { 594 if (!trust) { 595 _rtld_error("Tainted process refusing to run binary %s", 596 argv0); 597 rtld_die(); 598 } 599 direct_exec = true; 600 601 dbg("opening main program in direct exec mode"); 602 if (argc >= 2) { 603 rtld_argc = parse_args(argv, argc, &search_in_path, &fd, 604 &argv0, &dir_ignore); 605 explicit_fd = (fd != -1); 606 binpath = NULL; 607 if (!explicit_fd) 608 fd = open_binary_fd(argv0, search_in_path, &binpath); 609 if (fstat(fd, &st) == -1) { 610 _rtld_error("Failed to fstat FD %d (%s): %s", fd, 611 explicit_fd ? "user-provided descriptor" : argv0, 612 rtld_strerror(errno)); 613 rtld_die(); 614 } 615 616 /* 617 * Rough emulation of the permission checks done by 618 * execve(2), only Unix DACs are checked, ACLs are 619 * ignored. Preserve the semantic of disabling owner 620 * to execute if owner x bit is cleared, even if 621 * others x bit is enabled. 622 * mmap(2) does not allow to mmap with PROT_EXEC if 623 * binary' file comes from noexec mount. We cannot 624 * set a text reference on the binary. 625 */ 626 dir_enable = false; 627 if (st.st_uid == geteuid()) { 628 if ((st.st_mode & S_IXUSR) != 0) 629 dir_enable = true; 630 } else if (st.st_gid == getegid()) { 631 if ((st.st_mode & S_IXGRP) != 0) 632 dir_enable = true; 633 } else if ((st.st_mode & S_IXOTH) != 0) { 634 dir_enable = true; 635 } 636 if (!dir_enable && !dir_ignore) { 637 _rtld_error("No execute permission for binary %s", 638 argv0); 639 rtld_die(); 640 } 641 642 /* 643 * For direct exec mode, argv[0] is the interpreter 644 * name, we must remove it and shift arguments left 645 * before invoking binary main. Since stack layout 646 * places environment pointers and aux vectors right 647 * after the terminating NULL, we must shift 648 * environment and aux as well. 649 */ 650 main_argc = argc - rtld_argc; 651 for (i = 0; i <= main_argc; i++) 652 argv[i] = argv[i + rtld_argc]; 653 *argcp -= rtld_argc; 654 environ = env = envp = argv + main_argc + 1; 655 dbg("move env from %p to %p", envp + rtld_argc, envp); 656 do { 657 *envp = *(envp + rtld_argc); 658 } while (*envp++ != NULL); 659 aux = auxp = (Elf_Auxinfo *)envp; 660 auxpf = (Elf_Auxinfo *)(envp + rtld_argc); 661 dbg("move aux from %p to %p", auxpf, aux); 662 /* XXXKIB insert place for AT_EXECPATH if not present */ 663 for (;; auxp++, auxpf++) { 664 *auxp = *auxpf; 665 if (auxp->a_type == AT_NULL) 666 break; 667 } 668 /* Since the auxiliary vector has moved, redigest it. */ 669 for (i = 0; i < AT_COUNT; i++) 670 aux_info[i] = NULL; 671 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 672 if (auxp->a_type < AT_COUNT) 673 aux_info[auxp->a_type] = auxp; 674 } 675 676 /* Point AT_EXECPATH auxv and aux_info to the binary path. */ 677 if (binpath == NULL) { 678 aux_info[AT_EXECPATH] = NULL; 679 } else { 680 if (aux_info[AT_EXECPATH] == NULL) { 681 aux_info[AT_EXECPATH] = xmalloc(sizeof(Elf_Auxinfo)); 682 aux_info[AT_EXECPATH]->a_type = AT_EXECPATH; 683 } 684 aux_info[AT_EXECPATH]->a_un.a_ptr = __DECONST(void *, 685 binpath); 686 } 687 } else { 688 _rtld_error("No binary"); 689 rtld_die(); 690 } 691 } 692 } 693 694 ld_bind_now = ld_get_env_var(LD_BIND_NOW); 695 696 /* 697 * If the process is tainted, then we un-set the dangerous environment 698 * variables. The process will be marked as tainted until setuid(2) 699 * is called. If any child process calls setuid(2) we do not want any 700 * future processes to honor the potentially un-safe variables. 701 */ 702 if (!trust) { 703 for (i = 0; i < (int)nitems(ld_env_vars); i++) { 704 lvd = &ld_env_vars[i]; 705 if (lvd->unsecure) 706 lvd->val = NULL; 707 } 708 } 709 710 ld_debug = ld_get_env_var(LD_DEBUG); 711 if (ld_bind_now == NULL) 712 ld_bind_not = ld_get_env_var(LD_BIND_NOT) != NULL; 713 ld_dynamic_weak = ld_get_env_var(LD_DYNAMIC_WEAK) == NULL; 714 libmap_disable = ld_get_env_var(LD_LIBMAP_DISABLE) != NULL; 715 libmap_override = ld_get_env_var(LD_LIBMAP); 716 ld_library_path = ld_get_env_var(LD_LIBRARY_PATH); 717 ld_library_dirs = ld_get_env_var(LD_LIBRARY_PATH_FDS); 718 ld_preload = ld_get_env_var(LD_PRELOAD); 719 ld_preload_fds = ld_get_env_var(LD_PRELOAD_FDS); 720 ld_elf_hints_path = ld_get_env_var(LD_ELF_HINTS_PATH); 721 ld_loadfltr = ld_get_env_var(LD_LOADFLTR) != NULL; 722 library_path_rpath = ld_get_env_var(LD_LIBRARY_PATH_RPATH); 723 if (library_path_rpath != NULL) { 724 if (library_path_rpath[0] == 'y' || 725 library_path_rpath[0] == 'Y' || 726 library_path_rpath[0] == '1') 727 ld_library_path_rpath = true; 728 else 729 ld_library_path_rpath = false; 730 } 731 dangerous_ld_env = libmap_disable || libmap_override != NULL || 732 ld_library_path != NULL || ld_preload != NULL || 733 ld_elf_hints_path != NULL || ld_loadfltr || !ld_dynamic_weak; 734 ld_tracing = ld_get_env_var(LD_TRACE_LOADED_OBJECTS); 735 ld_utrace = ld_get_env_var(LD_UTRACE); 736 737 set_ld_elf_hints_path(); 738 if (ld_debug != NULL && *ld_debug != '\0') 739 debug = 1; 740 dbg("%s is initialized, base address = %p", __progname, 741 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 742 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 743 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 744 745 dbg("initializing thread locks"); 746 lockdflt_init(); 747 748 /* 749 * Load the main program, or process its program header if it is 750 * already loaded. 751 */ 752 if (fd != -1) { /* Load the main program. */ 753 dbg("loading main program"); 754 obj_main = map_object(fd, argv0, NULL); 755 close(fd); 756 if (obj_main == NULL) 757 rtld_die(); 758 max_stack_flags = obj_main->stack_flags; 759 } else { /* Main program already loaded. */ 760 dbg("processing main program's program header"); 761 assert(aux_info[AT_PHDR] != NULL); 762 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 763 assert(aux_info[AT_PHNUM] != NULL); 764 phnum = aux_info[AT_PHNUM]->a_un.a_val; 765 assert(aux_info[AT_PHENT] != NULL); 766 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 767 assert(aux_info[AT_ENTRY] != NULL); 768 imgentry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 769 if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) == NULL) 770 rtld_die(); 771 } 772 773 if (aux_info[AT_EXECPATH] != NULL && fd == -1) { 774 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 775 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 776 if (kexecpath[0] == '/') 777 obj_main->path = kexecpath; 778 else if (getcwd(buf, sizeof(buf)) == NULL || 779 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 780 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 781 obj_main->path = xstrdup(argv0); 782 else 783 obj_main->path = xstrdup(buf); 784 } else { 785 dbg("No AT_EXECPATH or direct exec"); 786 obj_main->path = xstrdup(argv0); 787 } 788 dbg("obj_main path %s", obj_main->path); 789 obj_main->mainprog = true; 790 791 if (aux_info[AT_STACKPROT] != NULL && 792 aux_info[AT_STACKPROT]->a_un.a_val != 0) 793 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 794 795 #ifndef COMPAT_32BIT 796 /* 797 * Get the actual dynamic linker pathname from the executable if 798 * possible. (It should always be possible.) That ensures that 799 * gdb will find the right dynamic linker even if a non-standard 800 * one is being used. 801 */ 802 if (obj_main->interp != NULL && 803 strcmp(obj_main->interp, obj_rtld.path) != 0) { 804 free(obj_rtld.path); 805 obj_rtld.path = xstrdup(obj_main->interp); 806 __progname = obj_rtld.path; 807 } 808 #endif 809 810 if (!digest_dynamic(obj_main, 0)) 811 rtld_die(); 812 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 813 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 814 obj_main->dynsymcount); 815 816 linkmap_add(obj_main); 817 linkmap_add(&obj_rtld); 818 819 /* Link the main program into the list of objects. */ 820 TAILQ_INSERT_HEAD(&obj_list, obj_main, next); 821 obj_count++; 822 obj_loads++; 823 824 /* Initialize a fake symbol for resolving undefined weak references. */ 825 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 826 sym_zero.st_shndx = SHN_UNDEF; 827 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 828 829 if (!libmap_disable) 830 libmap_disable = (bool)lm_init(libmap_override); 831 832 if (aux_info[AT_KPRELOAD] != NULL && 833 aux_info[AT_KPRELOAD]->a_un.a_ptr != NULL) { 834 dbg("loading kernel vdso"); 835 if (load_kpreload(aux_info[AT_KPRELOAD]->a_un.a_ptr) == -1) 836 rtld_die(); 837 } 838 839 dbg("loading LD_PRELOAD_FDS libraries"); 840 if (load_preload_objects(ld_preload_fds, true) == -1) 841 rtld_die(); 842 843 dbg("loading LD_PRELOAD libraries"); 844 if (load_preload_objects(ld_preload, false) == -1) 845 rtld_die(); 846 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 847 848 dbg("loading needed objects"); 849 if (load_needed_objects(obj_main, ld_tracing != NULL ? RTLD_LO_TRACE : 850 0) == -1) 851 rtld_die(); 852 853 /* Make a list of all objects loaded at startup. */ 854 last_interposer = obj_main; 855 TAILQ_FOREACH(obj, &obj_list, next) { 856 if (obj->marker) 857 continue; 858 if (obj->z_interpose && obj != obj_main) { 859 objlist_put_after(&list_main, last_interposer, obj); 860 last_interposer = obj; 861 } else { 862 objlist_push_tail(&list_main, obj); 863 } 864 obj->refcount++; 865 } 866 867 dbg("checking for required versions"); 868 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 869 rtld_die(); 870 871 if (ld_get_env_var(LD_SHOW_AUXV) != NULL) 872 dump_auxv(aux_info); 873 874 if (ld_tracing) { /* We're done */ 875 trace_loaded_objects(obj_main); 876 exit(0); 877 } 878 879 if (ld_get_env_var(LD_DUMP_REL_PRE) != NULL) { 880 dump_relocations(obj_main); 881 exit (0); 882 } 883 884 /* 885 * Processing tls relocations requires having the tls offsets 886 * initialized. Prepare offsets before starting initial 887 * relocation processing. 888 */ 889 dbg("initializing initial thread local storage offsets"); 890 STAILQ_FOREACH(entry, &list_main, link) { 891 /* 892 * Allocate all the initial objects out of the static TLS 893 * block even if they didn't ask for it. 894 */ 895 allocate_tls_offset(entry->obj); 896 } 897 898 if (relocate_objects(obj_main, 899 ld_bind_now != NULL && *ld_bind_now != '\0', 900 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 901 rtld_die(); 902 903 dbg("doing copy relocations"); 904 if (do_copy_relocations(obj_main) == -1) 905 rtld_die(); 906 907 if (ld_get_env_var(LD_DUMP_REL_POST) != NULL) { 908 dump_relocations(obj_main); 909 exit (0); 910 } 911 912 ifunc_init(aux); 913 914 /* 915 * Setup TLS for main thread. This must be done after the 916 * relocations are processed, since tls initialization section 917 * might be the subject for relocations. 918 */ 919 dbg("initializing initial thread local storage"); 920 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list))); 921 922 dbg("initializing key program variables"); 923 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 924 set_program_var("environ", env); 925 set_program_var("__elf_aux_vector", aux); 926 927 /* Make a list of init functions to call. */ 928 objlist_init(&initlist); 929 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)), 930 preload_tail, &initlist); 931 932 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 933 934 map_stacks_exec(NULL); 935 936 if (!obj_main->crt_no_init) { 937 /* 938 * Make sure we don't call the main program's init and fini 939 * functions for binaries linked with old crt1 which calls 940 * _init itself. 941 */ 942 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 943 obj_main->preinit_array = obj_main->init_array = 944 obj_main->fini_array = (Elf_Addr)NULL; 945 } 946 947 if (direct_exec) { 948 /* Set osrel for direct-execed binary */ 949 mib[0] = CTL_KERN; 950 mib[1] = KERN_PROC; 951 mib[2] = KERN_PROC_OSREL; 952 mib[3] = getpid(); 953 osrel = obj_main->osrel; 954 sz = sizeof(old_osrel); 955 dbg("setting osrel to %d", osrel); 956 (void)sysctl(mib, 4, &old_osrel, &sz, &osrel, sizeof(osrel)); 957 } 958 959 wlock_acquire(rtld_bind_lock, &lockstate); 960 961 dbg("resolving ifuncs"); 962 if (initlist_objects_ifunc(&initlist, ld_bind_now != NULL && 963 *ld_bind_now != '\0', SYMLOOK_EARLY, &lockstate) == -1) 964 rtld_die(); 965 966 rtld_exit_ptr = rtld_exit; 967 if (obj_main->crt_no_init) 968 preinit_main(); 969 objlist_call_init(&initlist, &lockstate); 970 _r_debug_postinit(&obj_main->linkmap); 971 objlist_clear(&initlist); 972 dbg("loading filtees"); 973 TAILQ_FOREACH(obj, &obj_list, next) { 974 if (obj->marker) 975 continue; 976 if (ld_loadfltr || obj->z_loadfltr) 977 load_filtees(obj, 0, &lockstate); 978 } 979 980 dbg("enforcing main obj relro"); 981 if (obj_enforce_relro(obj_main) == -1) 982 rtld_die(); 983 984 lock_release(rtld_bind_lock, &lockstate); 985 986 dbg("transferring control to program entry point = %p", obj_main->entry); 987 988 /* Return the exit procedure and the program entry point. */ 989 *exit_proc = rtld_exit_ptr; 990 *objp = obj_main; 991 return ((func_ptr_type)obj_main->entry); 992 } 993 994 void * 995 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 996 { 997 void *ptr; 998 Elf_Addr target; 999 1000 ptr = (void *)make_function_pointer(def, obj); 1001 target = call_ifunc_resolver(ptr); 1002 return ((void *)target); 1003 } 1004 1005 /* 1006 * NB: MIPS uses a private version of this function (_mips_rtld_bind). 1007 * Changes to this function should be applied there as well. 1008 */ 1009 Elf_Addr 1010 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 1011 { 1012 const Elf_Rel *rel; 1013 const Elf_Sym *def; 1014 const Obj_Entry *defobj; 1015 Elf_Addr *where; 1016 Elf_Addr target; 1017 RtldLockState lockstate; 1018 1019 rlock_acquire(rtld_bind_lock, &lockstate); 1020 if (sigsetjmp(lockstate.env, 0) != 0) 1021 lock_upgrade(rtld_bind_lock, &lockstate); 1022 if (obj->pltrel) 1023 rel = (const Elf_Rel *)((const char *)obj->pltrel + reloff); 1024 else 1025 rel = (const Elf_Rel *)((const char *)obj->pltrela + reloff); 1026 1027 where = (Elf_Addr *)(obj->relocbase + rel->r_offset); 1028 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT, 1029 NULL, &lockstate); 1030 if (def == NULL) 1031 rtld_die(); 1032 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 1033 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 1034 else 1035 target = (Elf_Addr)(defobj->relocbase + def->st_value); 1036 1037 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 1038 defobj->strtab + def->st_name, 1039 obj->path == NULL ? NULL : basename(obj->path), 1040 (void *)target, 1041 defobj->path == NULL ? NULL : basename(defobj->path)); 1042 1043 /* 1044 * Write the new contents for the jmpslot. Note that depending on 1045 * architecture, the value which we need to return back to the 1046 * lazy binding trampoline may or may not be the target 1047 * address. The value returned from reloc_jmpslot() is the value 1048 * that the trampoline needs. 1049 */ 1050 target = reloc_jmpslot(where, target, defobj, obj, rel); 1051 lock_release(rtld_bind_lock, &lockstate); 1052 return (target); 1053 } 1054 1055 /* 1056 * Error reporting function. Use it like printf. If formats the message 1057 * into a buffer, and sets things up so that the next call to dlerror() 1058 * will return the message. 1059 */ 1060 void 1061 _rtld_error(const char *fmt, ...) 1062 { 1063 va_list ap; 1064 1065 va_start(ap, fmt); 1066 rtld_vsnprintf(lockinfo.dlerror_loc(), lockinfo.dlerror_loc_sz, 1067 fmt, ap); 1068 va_end(ap); 1069 *lockinfo.dlerror_seen() = 0; 1070 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, lockinfo.dlerror_loc()); 1071 } 1072 1073 /* 1074 * Return a dynamically-allocated copy of the current error message, if any. 1075 */ 1076 static struct dlerror_save * 1077 errmsg_save(void) 1078 { 1079 struct dlerror_save *res; 1080 1081 res = xmalloc(sizeof(*res)); 1082 res->seen = *lockinfo.dlerror_seen(); 1083 if (res->seen == 0) 1084 res->msg = xstrdup(lockinfo.dlerror_loc()); 1085 return (res); 1086 } 1087 1088 /* 1089 * Restore the current error message from a copy which was previously saved 1090 * by errmsg_save(). The copy is freed. 1091 */ 1092 static void 1093 errmsg_restore(struct dlerror_save *saved_msg) 1094 { 1095 if (saved_msg == NULL || saved_msg->seen == 1) { 1096 *lockinfo.dlerror_seen() = 1; 1097 } else { 1098 *lockinfo.dlerror_seen() = 0; 1099 strlcpy(lockinfo.dlerror_loc(), saved_msg->msg, 1100 lockinfo.dlerror_loc_sz); 1101 free(saved_msg->msg); 1102 } 1103 free(saved_msg); 1104 } 1105 1106 static const char * 1107 basename(const char *name) 1108 { 1109 const char *p; 1110 1111 p = strrchr(name, '/'); 1112 return (p != NULL ? p + 1 : name); 1113 } 1114 1115 static struct utsname uts; 1116 1117 static char * 1118 origin_subst_one(Obj_Entry *obj, char *real, const char *kw, 1119 const char *subst, bool may_free) 1120 { 1121 char *p, *p1, *res, *resp; 1122 int subst_len, kw_len, subst_count, old_len, new_len; 1123 1124 kw_len = strlen(kw); 1125 1126 /* 1127 * First, count the number of the keyword occurrences, to 1128 * preallocate the final string. 1129 */ 1130 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 1131 p1 = strstr(p, kw); 1132 if (p1 == NULL) 1133 break; 1134 } 1135 1136 /* 1137 * If the keyword is not found, just return. 1138 * 1139 * Return non-substituted string if resolution failed. We 1140 * cannot do anything more reasonable, the failure mode of the 1141 * caller is unresolved library anyway. 1142 */ 1143 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj))) 1144 return (may_free ? real : xstrdup(real)); 1145 if (obj != NULL) 1146 subst = obj->origin_path; 1147 1148 /* 1149 * There is indeed something to substitute. Calculate the 1150 * length of the resulting string, and allocate it. 1151 */ 1152 subst_len = strlen(subst); 1153 old_len = strlen(real); 1154 new_len = old_len + (subst_len - kw_len) * subst_count; 1155 res = xmalloc(new_len + 1); 1156 1157 /* 1158 * Now, execute the substitution loop. 1159 */ 1160 for (p = real, resp = res, *resp = '\0';;) { 1161 p1 = strstr(p, kw); 1162 if (p1 != NULL) { 1163 /* Copy the prefix before keyword. */ 1164 memcpy(resp, p, p1 - p); 1165 resp += p1 - p; 1166 /* Keyword replacement. */ 1167 memcpy(resp, subst, subst_len); 1168 resp += subst_len; 1169 *resp = '\0'; 1170 p = p1 + kw_len; 1171 } else 1172 break; 1173 } 1174 1175 /* Copy to the end of string and finish. */ 1176 strcat(resp, p); 1177 if (may_free) 1178 free(real); 1179 return (res); 1180 } 1181 1182 static char * 1183 origin_subst(Obj_Entry *obj, const char *real) 1184 { 1185 char *res1, *res2, *res3, *res4; 1186 1187 if (obj == NULL || !trust) 1188 return (xstrdup(real)); 1189 if (uts.sysname[0] == '\0') { 1190 if (uname(&uts) != 0) { 1191 _rtld_error("utsname failed: %d", errno); 1192 return (NULL); 1193 } 1194 } 1195 /* __DECONST is safe here since without may_free real is unchanged */ 1196 res1 = origin_subst_one(obj, __DECONST(char *, real), "$ORIGIN", NULL, 1197 false); 1198 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true); 1199 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true); 1200 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true); 1201 return (res4); 1202 } 1203 1204 void 1205 rtld_die(void) 1206 { 1207 const char *msg = dlerror(); 1208 1209 if (msg == NULL) 1210 msg = "Fatal error"; 1211 rtld_fdputstr(STDERR_FILENO, _BASENAME_RTLD ": "); 1212 rtld_fdputstr(STDERR_FILENO, msg); 1213 rtld_fdputchar(STDERR_FILENO, '\n'); 1214 _exit(1); 1215 } 1216 1217 /* 1218 * Process a shared object's DYNAMIC section, and save the important 1219 * information in its Obj_Entry structure. 1220 */ 1221 static void 1222 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 1223 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 1224 { 1225 const Elf_Dyn *dynp; 1226 Needed_Entry **needed_tail = &obj->needed; 1227 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 1228 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 1229 const Elf_Hashelt *hashtab; 1230 const Elf32_Word *hashval; 1231 Elf32_Word bkt, nmaskwords; 1232 int bloom_size32; 1233 int plttype = DT_REL; 1234 1235 *dyn_rpath = NULL; 1236 *dyn_soname = NULL; 1237 *dyn_runpath = NULL; 1238 1239 obj->bind_now = false; 1240 dynp = obj->dynamic; 1241 if (dynp == NULL) 1242 return; 1243 for (; dynp->d_tag != DT_NULL; dynp++) { 1244 switch (dynp->d_tag) { 1245 1246 case DT_REL: 1247 obj->rel = (const Elf_Rel *)(obj->relocbase + dynp->d_un.d_ptr); 1248 break; 1249 1250 case DT_RELSZ: 1251 obj->relsize = dynp->d_un.d_val; 1252 break; 1253 1254 case DT_RELENT: 1255 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 1256 break; 1257 1258 case DT_JMPREL: 1259 obj->pltrel = (const Elf_Rel *) 1260 (obj->relocbase + dynp->d_un.d_ptr); 1261 break; 1262 1263 case DT_PLTRELSZ: 1264 obj->pltrelsize = dynp->d_un.d_val; 1265 break; 1266 1267 case DT_RELA: 1268 obj->rela = (const Elf_Rela *)(obj->relocbase + dynp->d_un.d_ptr); 1269 break; 1270 1271 case DT_RELASZ: 1272 obj->relasize = dynp->d_un.d_val; 1273 break; 1274 1275 case DT_RELAENT: 1276 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 1277 break; 1278 1279 case DT_RELR: 1280 obj->relr = (const Elf_Relr *)(obj->relocbase + dynp->d_un.d_ptr); 1281 break; 1282 1283 case DT_RELRSZ: 1284 obj->relrsize = dynp->d_un.d_val; 1285 break; 1286 1287 case DT_RELRENT: 1288 assert(dynp->d_un.d_val == sizeof(Elf_Relr)); 1289 break; 1290 1291 case DT_PLTREL: 1292 plttype = dynp->d_un.d_val; 1293 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 1294 break; 1295 1296 case DT_SYMTAB: 1297 obj->symtab = (const Elf_Sym *) 1298 (obj->relocbase + dynp->d_un.d_ptr); 1299 break; 1300 1301 case DT_SYMENT: 1302 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 1303 break; 1304 1305 case DT_STRTAB: 1306 obj->strtab = (const char *)(obj->relocbase + dynp->d_un.d_ptr); 1307 break; 1308 1309 case DT_STRSZ: 1310 obj->strsize = dynp->d_un.d_val; 1311 break; 1312 1313 case DT_VERNEED: 1314 obj->verneed = (const Elf_Verneed *)(obj->relocbase + 1315 dynp->d_un.d_val); 1316 break; 1317 1318 case DT_VERNEEDNUM: 1319 obj->verneednum = dynp->d_un.d_val; 1320 break; 1321 1322 case DT_VERDEF: 1323 obj->verdef = (const Elf_Verdef *)(obj->relocbase + 1324 dynp->d_un.d_val); 1325 break; 1326 1327 case DT_VERDEFNUM: 1328 obj->verdefnum = dynp->d_un.d_val; 1329 break; 1330 1331 case DT_VERSYM: 1332 obj->versyms = (const Elf_Versym *)(obj->relocbase + 1333 dynp->d_un.d_val); 1334 break; 1335 1336 case DT_HASH: 1337 { 1338 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1339 dynp->d_un.d_ptr); 1340 obj->nbuckets = hashtab[0]; 1341 obj->nchains = hashtab[1]; 1342 obj->buckets = hashtab + 2; 1343 obj->chains = obj->buckets + obj->nbuckets; 1344 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 1345 obj->buckets != NULL; 1346 } 1347 break; 1348 1349 case DT_GNU_HASH: 1350 { 1351 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1352 dynp->d_un.d_ptr); 1353 obj->nbuckets_gnu = hashtab[0]; 1354 obj->symndx_gnu = hashtab[1]; 1355 nmaskwords = hashtab[2]; 1356 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1357 obj->maskwords_bm_gnu = nmaskwords - 1; 1358 obj->shift2_gnu = hashtab[3]; 1359 obj->bloom_gnu = (const Elf_Addr *)(hashtab + 4); 1360 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1361 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1362 obj->symndx_gnu; 1363 /* Number of bitmask words is required to be power of 2 */ 1364 obj->valid_hash_gnu = powerof2(nmaskwords) && 1365 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1366 } 1367 break; 1368 1369 case DT_NEEDED: 1370 if (!obj->rtld) { 1371 Needed_Entry *nep = NEW(Needed_Entry); 1372 nep->name = dynp->d_un.d_val; 1373 nep->obj = NULL; 1374 nep->next = NULL; 1375 1376 *needed_tail = nep; 1377 needed_tail = &nep->next; 1378 } 1379 break; 1380 1381 case DT_FILTER: 1382 if (!obj->rtld) { 1383 Needed_Entry *nep = NEW(Needed_Entry); 1384 nep->name = dynp->d_un.d_val; 1385 nep->obj = NULL; 1386 nep->next = NULL; 1387 1388 *needed_filtees_tail = nep; 1389 needed_filtees_tail = &nep->next; 1390 1391 if (obj->linkmap.l_refname == NULL) 1392 obj->linkmap.l_refname = (char *)dynp->d_un.d_val; 1393 } 1394 break; 1395 1396 case DT_AUXILIARY: 1397 if (!obj->rtld) { 1398 Needed_Entry *nep = NEW(Needed_Entry); 1399 nep->name = dynp->d_un.d_val; 1400 nep->obj = NULL; 1401 nep->next = NULL; 1402 1403 *needed_aux_filtees_tail = nep; 1404 needed_aux_filtees_tail = &nep->next; 1405 } 1406 break; 1407 1408 case DT_PLTGOT: 1409 obj->pltgot = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr); 1410 break; 1411 1412 case DT_TEXTREL: 1413 obj->textrel = true; 1414 break; 1415 1416 case DT_SYMBOLIC: 1417 obj->symbolic = true; 1418 break; 1419 1420 case DT_RPATH: 1421 /* 1422 * We have to wait until later to process this, because we 1423 * might not have gotten the address of the string table yet. 1424 */ 1425 *dyn_rpath = dynp; 1426 break; 1427 1428 case DT_SONAME: 1429 *dyn_soname = dynp; 1430 break; 1431 1432 case DT_RUNPATH: 1433 *dyn_runpath = dynp; 1434 break; 1435 1436 case DT_INIT: 1437 obj->init = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1438 break; 1439 1440 case DT_PREINIT_ARRAY: 1441 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1442 break; 1443 1444 case DT_PREINIT_ARRAYSZ: 1445 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1446 break; 1447 1448 case DT_INIT_ARRAY: 1449 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1450 break; 1451 1452 case DT_INIT_ARRAYSZ: 1453 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1454 break; 1455 1456 case DT_FINI: 1457 obj->fini = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1458 break; 1459 1460 case DT_FINI_ARRAY: 1461 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1462 break; 1463 1464 case DT_FINI_ARRAYSZ: 1465 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1466 break; 1467 1468 /* 1469 * Don't process DT_DEBUG on MIPS as the dynamic section 1470 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1471 */ 1472 1473 #ifndef __mips__ 1474 case DT_DEBUG: 1475 if (!early) 1476 dbg("Filling in DT_DEBUG entry"); 1477 (__DECONST(Elf_Dyn *, dynp))->d_un.d_ptr = (Elf_Addr)&r_debug; 1478 break; 1479 #endif 1480 1481 case DT_FLAGS: 1482 if (dynp->d_un.d_val & DF_ORIGIN) 1483 obj->z_origin = true; 1484 if (dynp->d_un.d_val & DF_SYMBOLIC) 1485 obj->symbolic = true; 1486 if (dynp->d_un.d_val & DF_TEXTREL) 1487 obj->textrel = true; 1488 if (dynp->d_un.d_val & DF_BIND_NOW) 1489 obj->bind_now = true; 1490 if (dynp->d_un.d_val & DF_STATIC_TLS) 1491 obj->static_tls = true; 1492 break; 1493 #ifdef __mips__ 1494 case DT_MIPS_LOCAL_GOTNO: 1495 obj->local_gotno = dynp->d_un.d_val; 1496 break; 1497 1498 case DT_MIPS_SYMTABNO: 1499 obj->symtabno = dynp->d_un.d_val; 1500 break; 1501 1502 case DT_MIPS_GOTSYM: 1503 obj->gotsym = dynp->d_un.d_val; 1504 break; 1505 1506 case DT_MIPS_RLD_MAP: 1507 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1508 break; 1509 1510 case DT_MIPS_RLD_MAP_REL: 1511 // The MIPS_RLD_MAP_REL tag stores the offset to the .rld_map 1512 // section relative to the address of the tag itself. 1513 *((Elf_Addr *)(__DECONST(char*, dynp) + dynp->d_un.d_val)) = 1514 (Elf_Addr) &r_debug; 1515 break; 1516 1517 case DT_MIPS_PLTGOT: 1518 obj->mips_pltgot = (Elf_Addr *)(obj->relocbase + 1519 dynp->d_un.d_ptr); 1520 break; 1521 1522 #endif 1523 1524 #ifdef __powerpc__ 1525 #ifdef __powerpc64__ 1526 case DT_PPC64_GLINK: 1527 obj->glink = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1528 break; 1529 #else 1530 case DT_PPC_GOT: 1531 obj->gotptr = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr); 1532 break; 1533 #endif 1534 #endif 1535 1536 case DT_FLAGS_1: 1537 if (dynp->d_un.d_val & DF_1_NOOPEN) 1538 obj->z_noopen = true; 1539 if (dynp->d_un.d_val & DF_1_ORIGIN) 1540 obj->z_origin = true; 1541 if (dynp->d_un.d_val & DF_1_GLOBAL) 1542 obj->z_global = true; 1543 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1544 obj->bind_now = true; 1545 if (dynp->d_un.d_val & DF_1_NODELETE) 1546 obj->z_nodelete = true; 1547 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1548 obj->z_loadfltr = true; 1549 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1550 obj->z_interpose = true; 1551 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1552 obj->z_nodeflib = true; 1553 if (dynp->d_un.d_val & DF_1_PIE) 1554 obj->z_pie = true; 1555 break; 1556 1557 default: 1558 if (!early) { 1559 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1560 (long)dynp->d_tag); 1561 } 1562 break; 1563 } 1564 } 1565 1566 obj->traced = false; 1567 1568 if (plttype == DT_RELA) { 1569 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1570 obj->pltrel = NULL; 1571 obj->pltrelasize = obj->pltrelsize; 1572 obj->pltrelsize = 0; 1573 } 1574 1575 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1576 if (obj->valid_hash_sysv) 1577 obj->dynsymcount = obj->nchains; 1578 else if (obj->valid_hash_gnu) { 1579 obj->dynsymcount = 0; 1580 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1581 if (obj->buckets_gnu[bkt] == 0) 1582 continue; 1583 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1584 do 1585 obj->dynsymcount++; 1586 while ((*hashval++ & 1u) == 0); 1587 } 1588 obj->dynsymcount += obj->symndx_gnu; 1589 } 1590 1591 if (obj->linkmap.l_refname != NULL) 1592 obj->linkmap.l_refname = obj->strtab + (unsigned long)obj-> 1593 linkmap.l_refname; 1594 } 1595 1596 static bool 1597 obj_resolve_origin(Obj_Entry *obj) 1598 { 1599 1600 if (obj->origin_path != NULL) 1601 return (true); 1602 obj->origin_path = xmalloc(PATH_MAX); 1603 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1); 1604 } 1605 1606 static bool 1607 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1608 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1609 { 1610 1611 if (obj->z_origin && !obj_resolve_origin(obj)) 1612 return (false); 1613 1614 if (dyn_runpath != NULL) { 1615 obj->runpath = (const char *)obj->strtab + dyn_runpath->d_un.d_val; 1616 obj->runpath = origin_subst(obj, obj->runpath); 1617 } else if (dyn_rpath != NULL) { 1618 obj->rpath = (const char *)obj->strtab + dyn_rpath->d_un.d_val; 1619 obj->rpath = origin_subst(obj, obj->rpath); 1620 } 1621 if (dyn_soname != NULL) 1622 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1623 return (true); 1624 } 1625 1626 static bool 1627 digest_dynamic(Obj_Entry *obj, int early) 1628 { 1629 const Elf_Dyn *dyn_rpath; 1630 const Elf_Dyn *dyn_soname; 1631 const Elf_Dyn *dyn_runpath; 1632 1633 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1634 return (digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath)); 1635 } 1636 1637 /* 1638 * Process a shared object's program header. This is used only for the 1639 * main program, when the kernel has already loaded the main program 1640 * into memory before calling the dynamic linker. It creates and 1641 * returns an Obj_Entry structure. 1642 */ 1643 static Obj_Entry * 1644 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1645 { 1646 Obj_Entry *obj; 1647 const Elf_Phdr *phlimit = phdr + phnum; 1648 const Elf_Phdr *ph; 1649 Elf_Addr note_start, note_end; 1650 int nsegs = 0; 1651 1652 obj = obj_new(); 1653 for (ph = phdr; ph < phlimit; ph++) { 1654 if (ph->p_type != PT_PHDR) 1655 continue; 1656 1657 obj->phdr = phdr; 1658 obj->phsize = ph->p_memsz; 1659 obj->relocbase = __DECONST(char *, phdr) - ph->p_vaddr; 1660 break; 1661 } 1662 1663 obj->stack_flags = PF_X | PF_R | PF_W; 1664 1665 for (ph = phdr; ph < phlimit; ph++) { 1666 switch (ph->p_type) { 1667 1668 case PT_INTERP: 1669 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1670 break; 1671 1672 case PT_LOAD: 1673 if (nsegs == 0) { /* First load segment */ 1674 obj->vaddrbase = trunc_page(ph->p_vaddr); 1675 obj->mapbase = obj->vaddrbase + obj->relocbase; 1676 } else { /* Last load segment */ 1677 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1678 obj->vaddrbase; 1679 } 1680 nsegs++; 1681 break; 1682 1683 case PT_DYNAMIC: 1684 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1685 break; 1686 1687 case PT_TLS: 1688 obj->tlsindex = 1; 1689 obj->tlssize = ph->p_memsz; 1690 obj->tlsalign = ph->p_align; 1691 obj->tlsinitsize = ph->p_filesz; 1692 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1693 obj->tlspoffset = ph->p_offset; 1694 break; 1695 1696 case PT_GNU_STACK: 1697 obj->stack_flags = ph->p_flags; 1698 break; 1699 1700 case PT_GNU_RELRO: 1701 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1702 obj->relro_size = trunc_page(ph->p_vaddr + ph->p_memsz) - 1703 trunc_page(ph->p_vaddr); 1704 break; 1705 1706 case PT_NOTE: 1707 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1708 note_end = note_start + ph->p_filesz; 1709 digest_notes(obj, note_start, note_end); 1710 break; 1711 } 1712 } 1713 if (nsegs < 1) { 1714 _rtld_error("%s: too few PT_LOAD segments", path); 1715 return (NULL); 1716 } 1717 1718 obj->entry = entry; 1719 return (obj); 1720 } 1721 1722 void 1723 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1724 { 1725 const Elf_Note *note; 1726 const char *note_name; 1727 uintptr_t p; 1728 1729 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1730 note = (const Elf_Note *)((const char *)(note + 1) + 1731 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1732 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1733 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1734 note->n_descsz != sizeof(int32_t)) 1735 continue; 1736 if (note->n_type != NT_FREEBSD_ABI_TAG && 1737 note->n_type != NT_FREEBSD_FEATURE_CTL && 1738 note->n_type != NT_FREEBSD_NOINIT_TAG) 1739 continue; 1740 note_name = (const char *)(note + 1); 1741 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1742 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1743 continue; 1744 switch (note->n_type) { 1745 case NT_FREEBSD_ABI_TAG: 1746 /* FreeBSD osrel note */ 1747 p = (uintptr_t)(note + 1); 1748 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1749 obj->osrel = *(const int32_t *)(p); 1750 dbg("note osrel %d", obj->osrel); 1751 break; 1752 case NT_FREEBSD_FEATURE_CTL: 1753 /* FreeBSD ABI feature control note */ 1754 p = (uintptr_t)(note + 1); 1755 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1756 obj->fctl0 = *(const uint32_t *)(p); 1757 dbg("note fctl0 %#x", obj->fctl0); 1758 break; 1759 case NT_FREEBSD_NOINIT_TAG: 1760 /* FreeBSD 'crt does not call init' note */ 1761 obj->crt_no_init = true; 1762 dbg("note crt_no_init"); 1763 break; 1764 } 1765 } 1766 } 1767 1768 static Obj_Entry * 1769 dlcheck(void *handle) 1770 { 1771 Obj_Entry *obj; 1772 1773 TAILQ_FOREACH(obj, &obj_list, next) { 1774 if (obj == (Obj_Entry *) handle) 1775 break; 1776 } 1777 1778 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1779 _rtld_error("Invalid shared object handle %p", handle); 1780 return (NULL); 1781 } 1782 return (obj); 1783 } 1784 1785 /* 1786 * If the given object is already in the donelist, return true. Otherwise 1787 * add the object to the list and return false. 1788 */ 1789 static bool 1790 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1791 { 1792 unsigned int i; 1793 1794 for (i = 0; i < dlp->num_used; i++) 1795 if (dlp->objs[i] == obj) 1796 return (true); 1797 /* 1798 * Our donelist allocation should always be sufficient. But if 1799 * our threads locking isn't working properly, more shared objects 1800 * could have been loaded since we allocated the list. That should 1801 * never happen, but we'll handle it properly just in case it does. 1802 */ 1803 if (dlp->num_used < dlp->num_alloc) 1804 dlp->objs[dlp->num_used++] = obj; 1805 return (false); 1806 } 1807 1808 /* 1809 * Hash function for symbol table lookup. Don't even think about changing 1810 * this. It is specified by the System V ABI. 1811 */ 1812 unsigned long 1813 elf_hash(const char *name) 1814 { 1815 const unsigned char *p = (const unsigned char *) name; 1816 unsigned long h = 0; 1817 unsigned long g; 1818 1819 while (*p != '\0') { 1820 h = (h << 4) + *p++; 1821 if ((g = h & 0xf0000000) != 0) 1822 h ^= g >> 24; 1823 h &= ~g; 1824 } 1825 return (h); 1826 } 1827 1828 /* 1829 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1830 * unsigned in case it's implemented with a wider type. 1831 */ 1832 static uint32_t 1833 gnu_hash(const char *s) 1834 { 1835 uint32_t h; 1836 unsigned char c; 1837 1838 h = 5381; 1839 for (c = *s; c != '\0'; c = *++s) 1840 h = h * 33 + c; 1841 return (h & 0xffffffff); 1842 } 1843 1844 1845 /* 1846 * Find the library with the given name, and return its full pathname. 1847 * The returned string is dynamically allocated. Generates an error 1848 * message and returns NULL if the library cannot be found. 1849 * 1850 * If the second argument is non-NULL, then it refers to an already- 1851 * loaded shared object, whose library search path will be searched. 1852 * 1853 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1854 * descriptor (which is close-on-exec) will be passed out via the third 1855 * argument. 1856 * 1857 * The search order is: 1858 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1859 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1860 * LD_LIBRARY_PATH 1861 * DT_RUNPATH in the referencing file 1862 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1863 * from list) 1864 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1865 * 1866 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1867 */ 1868 static char * 1869 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1870 { 1871 char *pathname, *refobj_path; 1872 const char *name; 1873 bool nodeflib, objgiven; 1874 1875 objgiven = refobj != NULL; 1876 1877 if (libmap_disable || !objgiven || 1878 (name = lm_find(refobj->path, xname)) == NULL) 1879 name = xname; 1880 1881 if (strchr(name, '/') != NULL) { /* Hard coded pathname */ 1882 if (name[0] != '/' && !trust) { 1883 _rtld_error("Absolute pathname required " 1884 "for shared object \"%s\"", name); 1885 return (NULL); 1886 } 1887 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1888 __DECONST(char *, name))); 1889 } 1890 1891 dbg(" Searching for \"%s\"", name); 1892 refobj_path = objgiven ? refobj->path : NULL; 1893 1894 /* 1895 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1896 * back to pre-conforming behaviour if user requested so with 1897 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1898 * nodeflib. 1899 */ 1900 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1901 pathname = search_library_path(name, ld_library_path, 1902 refobj_path, fdp); 1903 if (pathname != NULL) 1904 return (pathname); 1905 if (refobj != NULL) { 1906 pathname = search_library_path(name, refobj->rpath, 1907 refobj_path, fdp); 1908 if (pathname != NULL) 1909 return (pathname); 1910 } 1911 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1912 if (pathname != NULL) 1913 return (pathname); 1914 pathname = search_library_path(name, gethints(false), 1915 refobj_path, fdp); 1916 if (pathname != NULL) 1917 return (pathname); 1918 pathname = search_library_path(name, ld_standard_library_path, 1919 refobj_path, fdp); 1920 if (pathname != NULL) 1921 return (pathname); 1922 } else { 1923 nodeflib = objgiven ? refobj->z_nodeflib : false; 1924 if (objgiven) { 1925 pathname = search_library_path(name, refobj->rpath, 1926 refobj->path, fdp); 1927 if (pathname != NULL) 1928 return (pathname); 1929 } 1930 if (objgiven && refobj->runpath == NULL && refobj != obj_main) { 1931 pathname = search_library_path(name, obj_main->rpath, 1932 refobj_path, fdp); 1933 if (pathname != NULL) 1934 return (pathname); 1935 } 1936 pathname = search_library_path(name, ld_library_path, 1937 refobj_path, fdp); 1938 if (pathname != NULL) 1939 return (pathname); 1940 if (objgiven) { 1941 pathname = search_library_path(name, refobj->runpath, 1942 refobj_path, fdp); 1943 if (pathname != NULL) 1944 return (pathname); 1945 } 1946 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1947 if (pathname != NULL) 1948 return (pathname); 1949 pathname = search_library_path(name, gethints(nodeflib), 1950 refobj_path, fdp); 1951 if (pathname != NULL) 1952 return (pathname); 1953 if (objgiven && !nodeflib) { 1954 pathname = search_library_path(name, 1955 ld_standard_library_path, refobj_path, fdp); 1956 if (pathname != NULL) 1957 return (pathname); 1958 } 1959 } 1960 1961 if (objgiven && refobj->path != NULL) { 1962 _rtld_error("Shared object \"%s\" not found, " 1963 "required by \"%s\"", name, basename(refobj->path)); 1964 } else { 1965 _rtld_error("Shared object \"%s\" not found", name); 1966 } 1967 return (NULL); 1968 } 1969 1970 /* 1971 * Given a symbol number in a referencing object, find the corresponding 1972 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1973 * no definition was found. Returns a pointer to the Obj_Entry of the 1974 * defining object via the reference parameter DEFOBJ_OUT. 1975 */ 1976 const Elf_Sym * 1977 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1978 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1979 RtldLockState *lockstate) 1980 { 1981 const Elf_Sym *ref; 1982 const Elf_Sym *def; 1983 const Obj_Entry *defobj; 1984 const Ver_Entry *ve; 1985 SymLook req; 1986 const char *name; 1987 int res; 1988 1989 /* 1990 * If we have already found this symbol, get the information from 1991 * the cache. 1992 */ 1993 if (symnum >= refobj->dynsymcount) 1994 return (NULL); /* Bad object */ 1995 if (cache != NULL && cache[symnum].sym != NULL) { 1996 *defobj_out = cache[symnum].obj; 1997 return (cache[symnum].sym); 1998 } 1999 2000 ref = refobj->symtab + symnum; 2001 name = refobj->strtab + ref->st_name; 2002 def = NULL; 2003 defobj = NULL; 2004 ve = NULL; 2005 2006 /* 2007 * We don't have to do a full scale lookup if the symbol is local. 2008 * We know it will bind to the instance in this load module; to 2009 * which we already have a pointer (ie ref). By not doing a lookup, 2010 * we not only improve performance, but it also avoids unresolvable 2011 * symbols when local symbols are not in the hash table. This has 2012 * been seen with the ia64 toolchain. 2013 */ 2014 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 2015 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 2016 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 2017 symnum); 2018 } 2019 symlook_init(&req, name); 2020 req.flags = flags; 2021 ve = req.ventry = fetch_ventry(refobj, symnum); 2022 req.lockstate = lockstate; 2023 res = symlook_default(&req, refobj); 2024 if (res == 0) { 2025 def = req.sym_out; 2026 defobj = req.defobj_out; 2027 } 2028 } else { 2029 def = ref; 2030 defobj = refobj; 2031 } 2032 2033 /* 2034 * If we found no definition and the reference is weak, treat the 2035 * symbol as having the value zero. 2036 */ 2037 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 2038 def = &sym_zero; 2039 defobj = obj_main; 2040 } 2041 2042 if (def != NULL) { 2043 *defobj_out = defobj; 2044 /* Record the information in the cache to avoid subsequent lookups. */ 2045 if (cache != NULL) { 2046 cache[symnum].sym = def; 2047 cache[symnum].obj = defobj; 2048 } 2049 } else { 2050 if (refobj != &obj_rtld) 2051 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name, 2052 ve != NULL ? "@" : "", ve != NULL ? ve->name : ""); 2053 } 2054 return (def); 2055 } 2056 2057 /* 2058 * Return the search path from the ldconfig hints file, reading it if 2059 * necessary. If nostdlib is true, then the default search paths are 2060 * not added to result. 2061 * 2062 * Returns NULL if there are problems with the hints file, 2063 * or if the search path there is empty. 2064 */ 2065 static const char * 2066 gethints(bool nostdlib) 2067 { 2068 static char *filtered_path; 2069 static const char *hints; 2070 static struct elfhints_hdr hdr; 2071 struct fill_search_info_args sargs, hargs; 2072 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 2073 struct dl_serpath *SLPpath, *hintpath; 2074 char *p; 2075 struct stat hint_stat; 2076 unsigned int SLPndx, hintndx, fndx, fcount; 2077 int fd; 2078 size_t flen; 2079 uint32_t dl; 2080 bool skip; 2081 2082 /* First call, read the hints file */ 2083 if (hints == NULL) { 2084 /* Keep from trying again in case the hints file is bad. */ 2085 hints = ""; 2086 2087 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 2088 return (NULL); 2089 2090 /* 2091 * Check of hdr.dirlistlen value against type limit 2092 * intends to pacify static analyzers. Further 2093 * paranoia leads to checks that dirlist is fully 2094 * contained in the file range. 2095 */ 2096 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 2097 hdr.magic != ELFHINTS_MAGIC || 2098 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 || 2099 fstat(fd, &hint_stat) == -1) { 2100 cleanup1: 2101 close(fd); 2102 hdr.dirlistlen = 0; 2103 return (NULL); 2104 } 2105 dl = hdr.strtab; 2106 if (dl + hdr.dirlist < dl) 2107 goto cleanup1; 2108 dl += hdr.dirlist; 2109 if (dl + hdr.dirlistlen < dl) 2110 goto cleanup1; 2111 dl += hdr.dirlistlen; 2112 if (dl > hint_stat.st_size) 2113 goto cleanup1; 2114 p = xmalloc(hdr.dirlistlen + 1); 2115 if (pread(fd, p, hdr.dirlistlen + 1, 2116 hdr.strtab + hdr.dirlist) != (ssize_t)hdr.dirlistlen + 1 || 2117 p[hdr.dirlistlen] != '\0') { 2118 free(p); 2119 goto cleanup1; 2120 } 2121 hints = p; 2122 close(fd); 2123 } 2124 2125 /* 2126 * If caller agreed to receive list which includes the default 2127 * paths, we are done. Otherwise, if we still did not 2128 * calculated filtered result, do it now. 2129 */ 2130 if (!nostdlib) 2131 return (hints[0] != '\0' ? hints : NULL); 2132 if (filtered_path != NULL) 2133 goto filt_ret; 2134 2135 /* 2136 * Obtain the list of all configured search paths, and the 2137 * list of the default paths. 2138 * 2139 * First estimate the size of the results. 2140 */ 2141 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2142 smeta.dls_cnt = 0; 2143 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2144 hmeta.dls_cnt = 0; 2145 2146 sargs.request = RTLD_DI_SERINFOSIZE; 2147 sargs.serinfo = &smeta; 2148 hargs.request = RTLD_DI_SERINFOSIZE; 2149 hargs.serinfo = &hmeta; 2150 2151 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 2152 &sargs); 2153 path_enumerate(hints, fill_search_info, NULL, &hargs); 2154 2155 SLPinfo = xmalloc(smeta.dls_size); 2156 hintinfo = xmalloc(hmeta.dls_size); 2157 2158 /* 2159 * Next fetch both sets of paths. 2160 */ 2161 sargs.request = RTLD_DI_SERINFO; 2162 sargs.serinfo = SLPinfo; 2163 sargs.serpath = &SLPinfo->dls_serpath[0]; 2164 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 2165 2166 hargs.request = RTLD_DI_SERINFO; 2167 hargs.serinfo = hintinfo; 2168 hargs.serpath = &hintinfo->dls_serpath[0]; 2169 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 2170 2171 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 2172 &sargs); 2173 path_enumerate(hints, fill_search_info, NULL, &hargs); 2174 2175 /* 2176 * Now calculate the difference between two sets, by excluding 2177 * standard paths from the full set. 2178 */ 2179 fndx = 0; 2180 fcount = 0; 2181 filtered_path = xmalloc(hdr.dirlistlen + 1); 2182 hintpath = &hintinfo->dls_serpath[0]; 2183 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 2184 skip = false; 2185 SLPpath = &SLPinfo->dls_serpath[0]; 2186 /* 2187 * Check each standard path against current. 2188 */ 2189 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 2190 /* matched, skip the path */ 2191 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 2192 skip = true; 2193 break; 2194 } 2195 } 2196 if (skip) 2197 continue; 2198 /* 2199 * Not matched against any standard path, add the path 2200 * to result. Separate consequtive paths with ':'. 2201 */ 2202 if (fcount > 0) { 2203 filtered_path[fndx] = ':'; 2204 fndx++; 2205 } 2206 fcount++; 2207 flen = strlen(hintpath->dls_name); 2208 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 2209 fndx += flen; 2210 } 2211 filtered_path[fndx] = '\0'; 2212 2213 free(SLPinfo); 2214 free(hintinfo); 2215 2216 filt_ret: 2217 return (filtered_path[0] != '\0' ? filtered_path : NULL); 2218 } 2219 2220 static void 2221 init_dag(Obj_Entry *root) 2222 { 2223 const Needed_Entry *needed; 2224 const Objlist_Entry *elm; 2225 DoneList donelist; 2226 2227 if (root->dag_inited) 2228 return; 2229 donelist_init(&donelist); 2230 2231 /* Root object belongs to own DAG. */ 2232 objlist_push_tail(&root->dldags, root); 2233 objlist_push_tail(&root->dagmembers, root); 2234 donelist_check(&donelist, root); 2235 2236 /* 2237 * Add dependencies of root object to DAG in breadth order 2238 * by exploiting the fact that each new object get added 2239 * to the tail of the dagmembers list. 2240 */ 2241 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2242 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 2243 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 2244 continue; 2245 objlist_push_tail(&needed->obj->dldags, root); 2246 objlist_push_tail(&root->dagmembers, needed->obj); 2247 } 2248 } 2249 root->dag_inited = true; 2250 } 2251 2252 static void 2253 init_marker(Obj_Entry *marker) 2254 { 2255 2256 bzero(marker, sizeof(*marker)); 2257 marker->marker = true; 2258 } 2259 2260 Obj_Entry * 2261 globallist_curr(const Obj_Entry *obj) 2262 { 2263 2264 for (;;) { 2265 if (obj == NULL) 2266 return (NULL); 2267 if (!obj->marker) 2268 return (__DECONST(Obj_Entry *, obj)); 2269 obj = TAILQ_PREV(obj, obj_entry_q, next); 2270 } 2271 } 2272 2273 Obj_Entry * 2274 globallist_next(const Obj_Entry *obj) 2275 { 2276 2277 for (;;) { 2278 obj = TAILQ_NEXT(obj, next); 2279 if (obj == NULL) 2280 return (NULL); 2281 if (!obj->marker) 2282 return (__DECONST(Obj_Entry *, obj)); 2283 } 2284 } 2285 2286 /* Prevent the object from being unmapped while the bind lock is dropped. */ 2287 static void 2288 hold_object(Obj_Entry *obj) 2289 { 2290 2291 obj->holdcount++; 2292 } 2293 2294 static void 2295 unhold_object(Obj_Entry *obj) 2296 { 2297 2298 assert(obj->holdcount > 0); 2299 if (--obj->holdcount == 0 && obj->unholdfree) 2300 release_object(obj); 2301 } 2302 2303 static void 2304 process_z(Obj_Entry *root) 2305 { 2306 const Objlist_Entry *elm; 2307 Obj_Entry *obj; 2308 2309 /* 2310 * Walk over object DAG and process every dependent object 2311 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 2312 * to grow their own DAG. 2313 * 2314 * For DF_1_GLOBAL, DAG is required for symbol lookups in 2315 * symlook_global() to work. 2316 * 2317 * For DF_1_NODELETE, the DAG should have its reference upped. 2318 */ 2319 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2320 obj = elm->obj; 2321 if (obj == NULL) 2322 continue; 2323 if (obj->z_nodelete && !obj->ref_nodel) { 2324 dbg("obj %s -z nodelete", obj->path); 2325 init_dag(obj); 2326 ref_dag(obj); 2327 obj->ref_nodel = true; 2328 } 2329 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 2330 dbg("obj %s -z global", obj->path); 2331 objlist_push_tail(&list_global, obj); 2332 init_dag(obj); 2333 } 2334 } 2335 } 2336 2337 static void 2338 parse_rtld_phdr(Obj_Entry *obj) 2339 { 2340 const Elf_Phdr *ph; 2341 Elf_Addr note_start, note_end; 2342 2343 obj->stack_flags = PF_X | PF_R | PF_W; 2344 for (ph = obj->phdr; (const char *)ph < (const char *)obj->phdr + 2345 obj->phsize; ph++) { 2346 switch (ph->p_type) { 2347 case PT_GNU_STACK: 2348 obj->stack_flags = ph->p_flags; 2349 break; 2350 case PT_GNU_RELRO: 2351 obj->relro_page = obj->relocbase + 2352 trunc_page(ph->p_vaddr); 2353 obj->relro_size = round_page(ph->p_memsz); 2354 break; 2355 case PT_NOTE: 2356 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 2357 note_end = note_start + ph->p_filesz; 2358 digest_notes(obj, note_start, note_end); 2359 break; 2360 } 2361 } 2362 } 2363 2364 /* 2365 * Initialize the dynamic linker. The argument is the address at which 2366 * the dynamic linker has been mapped into memory. The primary task of 2367 * this function is to relocate the dynamic linker. 2368 */ 2369 static void 2370 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 2371 { 2372 Obj_Entry objtmp; /* Temporary rtld object */ 2373 const Elf_Ehdr *ehdr; 2374 const Elf_Dyn *dyn_rpath; 2375 const Elf_Dyn *dyn_soname; 2376 const Elf_Dyn *dyn_runpath; 2377 2378 #ifdef RTLD_INIT_PAGESIZES_EARLY 2379 /* The page size is required by the dynamic memory allocator. */ 2380 init_pagesizes(aux_info); 2381 #endif 2382 2383 /* 2384 * Conjure up an Obj_Entry structure for the dynamic linker. 2385 * 2386 * The "path" member can't be initialized yet because string constants 2387 * cannot yet be accessed. Below we will set it correctly. 2388 */ 2389 memset(&objtmp, 0, sizeof(objtmp)); 2390 objtmp.path = NULL; 2391 objtmp.rtld = true; 2392 objtmp.mapbase = mapbase; 2393 #ifdef PIC 2394 objtmp.relocbase = mapbase; 2395 #endif 2396 2397 objtmp.dynamic = rtld_dynamic(&objtmp); 2398 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 2399 assert(objtmp.needed == NULL); 2400 #if !defined(__mips__) 2401 /* MIPS has a bogus DT_TEXTREL. */ 2402 assert(!objtmp.textrel); 2403 #endif 2404 /* 2405 * Temporarily put the dynamic linker entry into the object list, so 2406 * that symbols can be found. 2407 */ 2408 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 2409 2410 ehdr = (Elf_Ehdr *)mapbase; 2411 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 2412 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 2413 2414 /* Initialize the object list. */ 2415 TAILQ_INIT(&obj_list); 2416 2417 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 2418 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 2419 2420 #ifndef RTLD_INIT_PAGESIZES_EARLY 2421 /* The page size is required by the dynamic memory allocator. */ 2422 init_pagesizes(aux_info); 2423 #endif 2424 2425 if (aux_info[AT_OSRELDATE] != NULL) 2426 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 2427 2428 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 2429 2430 /* Replace the path with a dynamically allocated copy. */ 2431 obj_rtld.path = xstrdup(ld_path_rtld); 2432 2433 parse_rtld_phdr(&obj_rtld); 2434 if (obj_enforce_relro(&obj_rtld) == -1) 2435 rtld_die(); 2436 2437 r_debug.r_version = R_DEBUG_VERSION; 2438 r_debug.r_brk = r_debug_state; 2439 r_debug.r_state = RT_CONSISTENT; 2440 r_debug.r_ldbase = obj_rtld.relocbase; 2441 } 2442 2443 /* 2444 * Retrieve the array of supported page sizes. The kernel provides the page 2445 * sizes in increasing order. 2446 */ 2447 static void 2448 init_pagesizes(Elf_Auxinfo **aux_info) 2449 { 2450 static size_t psa[MAXPAGESIZES]; 2451 int mib[2]; 2452 size_t len, size; 2453 2454 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 2455 NULL) { 2456 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 2457 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 2458 } else { 2459 len = 2; 2460 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 2461 size = sizeof(psa); 2462 else { 2463 /* As a fallback, retrieve the base page size. */ 2464 size = sizeof(psa[0]); 2465 if (aux_info[AT_PAGESZ] != NULL) { 2466 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 2467 goto psa_filled; 2468 } else { 2469 mib[0] = CTL_HW; 2470 mib[1] = HW_PAGESIZE; 2471 len = 2; 2472 } 2473 } 2474 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 2475 _rtld_error("sysctl for hw.pagesize(s) failed"); 2476 rtld_die(); 2477 } 2478 psa_filled: 2479 pagesizes = psa; 2480 } 2481 npagesizes = size / sizeof(pagesizes[0]); 2482 /* Discard any invalid entries at the end of the array. */ 2483 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 2484 npagesizes--; 2485 } 2486 2487 /* 2488 * Add the init functions from a needed object list (and its recursive 2489 * needed objects) to "list". This is not used directly; it is a helper 2490 * function for initlist_add_objects(). The write lock must be held 2491 * when this function is called. 2492 */ 2493 static void 2494 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 2495 { 2496 /* Recursively process the successor needed objects. */ 2497 if (needed->next != NULL) 2498 initlist_add_neededs(needed->next, list); 2499 2500 /* Process the current needed object. */ 2501 if (needed->obj != NULL) 2502 initlist_add_objects(needed->obj, needed->obj, list); 2503 } 2504 2505 /* 2506 * Scan all of the DAGs rooted in the range of objects from "obj" to 2507 * "tail" and add their init functions to "list". This recurses over 2508 * the DAGs and ensure the proper init ordering such that each object's 2509 * needed libraries are initialized before the object itself. At the 2510 * same time, this function adds the objects to the global finalization 2511 * list "list_fini" in the opposite order. The write lock must be 2512 * held when this function is called. 2513 */ 2514 static void 2515 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2516 { 2517 Obj_Entry *nobj; 2518 2519 if (obj->init_scanned || obj->init_done) 2520 return; 2521 obj->init_scanned = true; 2522 2523 /* Recursively process the successor objects. */ 2524 nobj = globallist_next(obj); 2525 if (nobj != NULL && obj != tail) 2526 initlist_add_objects(nobj, tail, list); 2527 2528 /* Recursively process the needed objects. */ 2529 if (obj->needed != NULL) 2530 initlist_add_neededs(obj->needed, list); 2531 if (obj->needed_filtees != NULL) 2532 initlist_add_neededs(obj->needed_filtees, list); 2533 if (obj->needed_aux_filtees != NULL) 2534 initlist_add_neededs(obj->needed_aux_filtees, list); 2535 2536 /* Add the object to the init list. */ 2537 objlist_push_tail(list, obj); 2538 2539 /* Add the object to the global fini list in the reverse order. */ 2540 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2541 && !obj->on_fini_list) { 2542 objlist_push_head(&list_fini, obj); 2543 obj->on_fini_list = true; 2544 } 2545 } 2546 2547 #ifndef FPTR_TARGET 2548 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 2549 #endif 2550 2551 static void 2552 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate) 2553 { 2554 Needed_Entry *needed, *needed1; 2555 2556 for (needed = n; needed != NULL; needed = needed->next) { 2557 if (needed->obj != NULL) { 2558 dlclose_locked(needed->obj, lockstate); 2559 needed->obj = NULL; 2560 } 2561 } 2562 for (needed = n; needed != NULL; needed = needed1) { 2563 needed1 = needed->next; 2564 free(needed); 2565 } 2566 } 2567 2568 static void 2569 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate) 2570 { 2571 2572 free_needed_filtees(obj->needed_filtees, lockstate); 2573 obj->needed_filtees = NULL; 2574 free_needed_filtees(obj->needed_aux_filtees, lockstate); 2575 obj->needed_aux_filtees = NULL; 2576 obj->filtees_loaded = false; 2577 } 2578 2579 static void 2580 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2581 RtldLockState *lockstate) 2582 { 2583 2584 for (; needed != NULL; needed = needed->next) { 2585 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2586 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2587 RTLD_LOCAL, lockstate); 2588 } 2589 } 2590 2591 static void 2592 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2593 { 2594 2595 lock_restart_for_upgrade(lockstate); 2596 if (!obj->filtees_loaded) { 2597 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2598 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2599 obj->filtees_loaded = true; 2600 } 2601 } 2602 2603 static int 2604 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2605 { 2606 Obj_Entry *obj1; 2607 2608 for (; needed != NULL; needed = needed->next) { 2609 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2610 flags & ~RTLD_LO_NOLOAD); 2611 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2612 return (-1); 2613 } 2614 return (0); 2615 } 2616 2617 /* 2618 * Given a shared object, traverse its list of needed objects, and load 2619 * each of them. Returns 0 on success. Generates an error message and 2620 * returns -1 on failure. 2621 */ 2622 static int 2623 load_needed_objects(Obj_Entry *first, int flags) 2624 { 2625 Obj_Entry *obj; 2626 2627 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2628 if (obj->marker) 2629 continue; 2630 if (process_needed(obj, obj->needed, flags) == -1) 2631 return (-1); 2632 } 2633 return (0); 2634 } 2635 2636 static int 2637 load_preload_objects(const char *penv, bool isfd) 2638 { 2639 Obj_Entry *obj; 2640 const char *name; 2641 size_t len; 2642 char savech, *p, *psave; 2643 int fd; 2644 static const char delim[] = " \t:;"; 2645 2646 if (penv == NULL) 2647 return (0); 2648 2649 p = psave = xstrdup(penv); 2650 p += strspn(p, delim); 2651 while (*p != '\0') { 2652 len = strcspn(p, delim); 2653 2654 savech = p[len]; 2655 p[len] = '\0'; 2656 if (isfd) { 2657 name = NULL; 2658 fd = parse_integer(p); 2659 if (fd == -1) { 2660 free(psave); 2661 return (-1); 2662 } 2663 } else { 2664 name = p; 2665 fd = -1; 2666 } 2667 2668 obj = load_object(name, fd, NULL, 0); 2669 if (obj == NULL) { 2670 free(psave); 2671 return (-1); /* XXX - cleanup */ 2672 } 2673 obj->z_interpose = true; 2674 p[len] = savech; 2675 p += len; 2676 p += strspn(p, delim); 2677 } 2678 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2679 2680 free(psave); 2681 return (0); 2682 } 2683 2684 static const char * 2685 printable_path(const char *path) 2686 { 2687 2688 return (path == NULL ? "<unknown>" : path); 2689 } 2690 2691 /* 2692 * Load a shared object into memory, if it is not already loaded. The 2693 * object may be specified by name or by user-supplied file descriptor 2694 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2695 * duplicate is. 2696 * 2697 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2698 * on failure. 2699 */ 2700 static Obj_Entry * 2701 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2702 { 2703 Obj_Entry *obj; 2704 int fd; 2705 struct stat sb; 2706 char *path; 2707 2708 fd = -1; 2709 if (name != NULL) { 2710 TAILQ_FOREACH(obj, &obj_list, next) { 2711 if (obj->marker || obj->doomed) 2712 continue; 2713 if (object_match_name(obj, name)) 2714 return (obj); 2715 } 2716 2717 path = find_library(name, refobj, &fd); 2718 if (path == NULL) 2719 return (NULL); 2720 } else 2721 path = NULL; 2722 2723 if (fd >= 0) { 2724 /* 2725 * search_library_pathfds() opens a fresh file descriptor for the 2726 * library, so there is no need to dup(). 2727 */ 2728 } else if (fd_u == -1) { 2729 /* 2730 * If we didn't find a match by pathname, or the name is not 2731 * supplied, open the file and check again by device and inode. 2732 * This avoids false mismatches caused by multiple links or ".." 2733 * in pathnames. 2734 * 2735 * To avoid a race, we open the file and use fstat() rather than 2736 * using stat(). 2737 */ 2738 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { 2739 _rtld_error("Cannot open \"%s\"", path); 2740 free(path); 2741 return (NULL); 2742 } 2743 } else { 2744 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2745 if (fd == -1) { 2746 _rtld_error("Cannot dup fd"); 2747 free(path); 2748 return (NULL); 2749 } 2750 } 2751 if (fstat(fd, &sb) == -1) { 2752 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2753 close(fd); 2754 free(path); 2755 return (NULL); 2756 } 2757 TAILQ_FOREACH(obj, &obj_list, next) { 2758 if (obj->marker || obj->doomed) 2759 continue; 2760 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2761 break; 2762 } 2763 if (obj != NULL && name != NULL) { 2764 object_add_name(obj, name); 2765 free(path); 2766 close(fd); 2767 return (obj); 2768 } 2769 if (flags & RTLD_LO_NOLOAD) { 2770 free(path); 2771 close(fd); 2772 return (NULL); 2773 } 2774 2775 /* First use of this object, so we must map it in */ 2776 obj = do_load_object(fd, name, path, &sb, flags); 2777 if (obj == NULL) 2778 free(path); 2779 close(fd); 2780 2781 return (obj); 2782 } 2783 2784 static Obj_Entry * 2785 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2786 int flags) 2787 { 2788 Obj_Entry *obj; 2789 struct statfs fs; 2790 2791 /* 2792 * First, make sure that environment variables haven't been 2793 * used to circumvent the noexec flag on a filesystem. 2794 * We ignore fstatfs(2) failures, since fd might reference 2795 * not a file, e.g. shmfd. 2796 */ 2797 if (dangerous_ld_env && fstatfs(fd, &fs) == 0 && 2798 (fs.f_flags & MNT_NOEXEC) != 0) { 2799 _rtld_error("Cannot execute objects on %s", fs.f_mntonname); 2800 return (NULL); 2801 } 2802 2803 dbg("loading \"%s\"", printable_path(path)); 2804 obj = map_object(fd, printable_path(path), sbp); 2805 if (obj == NULL) 2806 return (NULL); 2807 2808 /* 2809 * If DT_SONAME is present in the object, digest_dynamic2 already 2810 * added it to the object names. 2811 */ 2812 if (name != NULL) 2813 object_add_name(obj, name); 2814 obj->path = path; 2815 if (!digest_dynamic(obj, 0)) 2816 goto errp; 2817 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2818 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2819 if (obj->z_pie && (flags & RTLD_LO_TRACE) == 0) { 2820 dbg("refusing to load PIE executable \"%s\"", obj->path); 2821 _rtld_error("Cannot load PIE binary %s as DSO", obj->path); 2822 goto errp; 2823 } 2824 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2825 RTLD_LO_DLOPEN) { 2826 dbg("refusing to load non-loadable \"%s\"", obj->path); 2827 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2828 goto errp; 2829 } 2830 2831 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2832 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2833 obj_count++; 2834 obj_loads++; 2835 linkmap_add(obj); /* for GDB & dlinfo() */ 2836 max_stack_flags |= obj->stack_flags; 2837 2838 dbg(" %p .. %p: %s", obj->mapbase, 2839 obj->mapbase + obj->mapsize - 1, obj->path); 2840 if (obj->textrel) 2841 dbg(" WARNING: %s has impure text", obj->path); 2842 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2843 obj->path); 2844 2845 return (obj); 2846 2847 errp: 2848 munmap(obj->mapbase, obj->mapsize); 2849 obj_free(obj); 2850 return (NULL); 2851 } 2852 2853 static int 2854 load_kpreload(const void *addr) 2855 { 2856 Obj_Entry *obj; 2857 const Elf_Ehdr *ehdr; 2858 const Elf_Phdr *phdr, *phlimit, *phdyn, *seg0, *segn; 2859 static const char kname[] = "[vdso]"; 2860 2861 ehdr = addr; 2862 if (!check_elf_headers(ehdr, "kpreload")) 2863 return (-1); 2864 obj = obj_new(); 2865 phdr = (const Elf_Phdr *)((const char *)addr + ehdr->e_phoff); 2866 obj->phdr = phdr; 2867 obj->phsize = ehdr->e_phnum * sizeof(*phdr); 2868 phlimit = phdr + ehdr->e_phnum; 2869 seg0 = segn = NULL; 2870 2871 for (; phdr < phlimit; phdr++) { 2872 switch (phdr->p_type) { 2873 case PT_DYNAMIC: 2874 phdyn = phdr; 2875 break; 2876 case PT_GNU_STACK: 2877 /* Absense of PT_GNU_STACK implies stack_flags == 0. */ 2878 obj->stack_flags = phdr->p_flags; 2879 break; 2880 case PT_LOAD: 2881 if (seg0 == NULL || seg0->p_vaddr > phdr->p_vaddr) 2882 seg0 = phdr; 2883 if (segn == NULL || segn->p_vaddr + segn->p_memsz < 2884 phdr->p_vaddr + phdr->p_memsz) 2885 segn = phdr; 2886 break; 2887 } 2888 } 2889 2890 obj->mapbase = __DECONST(caddr_t, addr); 2891 obj->mapsize = segn->p_vaddr + segn->p_memsz - (Elf_Addr)addr; 2892 obj->vaddrbase = 0; 2893 obj->relocbase = obj->mapbase; 2894 2895 object_add_name(obj, kname); 2896 obj->path = xstrdup(kname); 2897 obj->dynamic = (const Elf_Dyn *)(obj->relocbase + phdyn->p_vaddr); 2898 2899 if (!digest_dynamic(obj, 0)) { 2900 obj_free(obj); 2901 return (-1); 2902 } 2903 2904 /* 2905 * We assume that kernel-preloaded object does not need 2906 * relocation. It is currently written into read-only page, 2907 * handling relocations would mean we need to allocate at 2908 * least one additional page per AS. 2909 */ 2910 dbg("%s mapbase %p phdrs %p PT_LOAD phdr %p vaddr %p dynamic %p", 2911 obj->path, obj->mapbase, obj->phdr, seg0, 2912 obj->relocbase + seg0->p_vaddr, obj->dynamic); 2913 2914 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2915 obj_count++; 2916 obj_loads++; 2917 linkmap_add(obj); /* for GDB & dlinfo() */ 2918 max_stack_flags |= obj->stack_flags; 2919 2920 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, 0, 0, obj->path); 2921 return (0); 2922 } 2923 2924 Obj_Entry * 2925 obj_from_addr(const void *addr) 2926 { 2927 Obj_Entry *obj; 2928 2929 TAILQ_FOREACH(obj, &obj_list, next) { 2930 if (obj->marker) 2931 continue; 2932 if (addr < (void *) obj->mapbase) 2933 continue; 2934 if (addr < (void *)(obj->mapbase + obj->mapsize)) 2935 return obj; 2936 } 2937 return (NULL); 2938 } 2939 2940 static void 2941 preinit_main(void) 2942 { 2943 Elf_Addr *preinit_addr; 2944 int index; 2945 2946 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2947 if (preinit_addr == NULL) 2948 return; 2949 2950 for (index = 0; index < obj_main->preinit_array_num; index++) { 2951 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2952 dbg("calling preinit function for %s at %p", obj_main->path, 2953 (void *)preinit_addr[index]); 2954 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2955 0, 0, obj_main->path); 2956 call_init_pointer(obj_main, preinit_addr[index]); 2957 } 2958 } 2959 } 2960 2961 /* 2962 * Call the finalization functions for each of the objects in "list" 2963 * belonging to the DAG of "root" and referenced once. If NULL "root" 2964 * is specified, every finalization function will be called regardless 2965 * of the reference count and the list elements won't be freed. All of 2966 * the objects are expected to have non-NULL fini functions. 2967 */ 2968 static void 2969 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2970 { 2971 Objlist_Entry *elm; 2972 struct dlerror_save *saved_msg; 2973 Elf_Addr *fini_addr; 2974 int index; 2975 2976 assert(root == NULL || root->refcount == 1); 2977 2978 if (root != NULL) 2979 root->doomed = true; 2980 2981 /* 2982 * Preserve the current error message since a fini function might 2983 * call into the dynamic linker and overwrite it. 2984 */ 2985 saved_msg = errmsg_save(); 2986 do { 2987 STAILQ_FOREACH(elm, list, link) { 2988 if (root != NULL && (elm->obj->refcount != 1 || 2989 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2990 continue; 2991 /* Remove object from fini list to prevent recursive invocation. */ 2992 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2993 /* Ensure that new references cannot be acquired. */ 2994 elm->obj->doomed = true; 2995 2996 hold_object(elm->obj); 2997 lock_release(rtld_bind_lock, lockstate); 2998 /* 2999 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 3000 * When this happens, DT_FINI_ARRAY is processed first. 3001 */ 3002 fini_addr = (Elf_Addr *)elm->obj->fini_array; 3003 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 3004 for (index = elm->obj->fini_array_num - 1; index >= 0; 3005 index--) { 3006 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 3007 dbg("calling fini function for %s at %p", 3008 elm->obj->path, (void *)fini_addr[index]); 3009 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 3010 (void *)fini_addr[index], 0, 0, elm->obj->path); 3011 call_initfini_pointer(elm->obj, fini_addr[index]); 3012 } 3013 } 3014 } 3015 if (elm->obj->fini != (Elf_Addr)NULL) { 3016 dbg("calling fini function for %s at %p", elm->obj->path, 3017 (void *)elm->obj->fini); 3018 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 3019 0, 0, elm->obj->path); 3020 call_initfini_pointer(elm->obj, elm->obj->fini); 3021 } 3022 wlock_acquire(rtld_bind_lock, lockstate); 3023 unhold_object(elm->obj); 3024 /* No need to free anything if process is going down. */ 3025 if (root != NULL) 3026 free(elm); 3027 /* 3028 * We must restart the list traversal after every fini call 3029 * because a dlclose() call from the fini function or from 3030 * another thread might have modified the reference counts. 3031 */ 3032 break; 3033 } 3034 } while (elm != NULL); 3035 errmsg_restore(saved_msg); 3036 } 3037 3038 /* 3039 * Call the initialization functions for each of the objects in 3040 * "list". All of the objects are expected to have non-NULL init 3041 * functions. 3042 */ 3043 static void 3044 objlist_call_init(Objlist *list, RtldLockState *lockstate) 3045 { 3046 Objlist_Entry *elm; 3047 Obj_Entry *obj; 3048 struct dlerror_save *saved_msg; 3049 Elf_Addr *init_addr; 3050 void (*reg)(void (*)(void)); 3051 int index; 3052 3053 /* 3054 * Clean init_scanned flag so that objects can be rechecked and 3055 * possibly initialized earlier if any of vectors called below 3056 * cause the change by using dlopen. 3057 */ 3058 TAILQ_FOREACH(obj, &obj_list, next) { 3059 if (obj->marker) 3060 continue; 3061 obj->init_scanned = false; 3062 } 3063 3064 /* 3065 * Preserve the current error message since an init function might 3066 * call into the dynamic linker and overwrite it. 3067 */ 3068 saved_msg = errmsg_save(); 3069 STAILQ_FOREACH(elm, list, link) { 3070 if (elm->obj->init_done) /* Initialized early. */ 3071 continue; 3072 /* 3073 * Race: other thread might try to use this object before current 3074 * one completes the initialization. Not much can be done here 3075 * without better locking. 3076 */ 3077 elm->obj->init_done = true; 3078 hold_object(elm->obj); 3079 reg = NULL; 3080 if (elm->obj == obj_main && obj_main->crt_no_init) { 3081 reg = (void (*)(void (*)(void)))get_program_var_addr( 3082 "__libc_atexit", lockstate); 3083 } 3084 lock_release(rtld_bind_lock, lockstate); 3085 if (reg != NULL) { 3086 reg(rtld_exit); 3087 rtld_exit_ptr = rtld_nop_exit; 3088 } 3089 3090 /* 3091 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 3092 * When this happens, DT_INIT is processed first. 3093 */ 3094 if (elm->obj->init != (Elf_Addr)NULL) { 3095 dbg("calling init function for %s at %p", elm->obj->path, 3096 (void *)elm->obj->init); 3097 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 3098 0, 0, elm->obj->path); 3099 call_init_pointer(elm->obj, elm->obj->init); 3100 } 3101 init_addr = (Elf_Addr *)elm->obj->init_array; 3102 if (init_addr != NULL) { 3103 for (index = 0; index < elm->obj->init_array_num; index++) { 3104 if (init_addr[index] != 0 && init_addr[index] != 1) { 3105 dbg("calling init function for %s at %p", elm->obj->path, 3106 (void *)init_addr[index]); 3107 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 3108 (void *)init_addr[index], 0, 0, elm->obj->path); 3109 call_init_pointer(elm->obj, init_addr[index]); 3110 } 3111 } 3112 } 3113 wlock_acquire(rtld_bind_lock, lockstate); 3114 unhold_object(elm->obj); 3115 } 3116 errmsg_restore(saved_msg); 3117 } 3118 3119 static void 3120 objlist_clear(Objlist *list) 3121 { 3122 Objlist_Entry *elm; 3123 3124 while (!STAILQ_EMPTY(list)) { 3125 elm = STAILQ_FIRST(list); 3126 STAILQ_REMOVE_HEAD(list, link); 3127 free(elm); 3128 } 3129 } 3130 3131 static Objlist_Entry * 3132 objlist_find(Objlist *list, const Obj_Entry *obj) 3133 { 3134 Objlist_Entry *elm; 3135 3136 STAILQ_FOREACH(elm, list, link) 3137 if (elm->obj == obj) 3138 return elm; 3139 return (NULL); 3140 } 3141 3142 static void 3143 objlist_init(Objlist *list) 3144 { 3145 STAILQ_INIT(list); 3146 } 3147 3148 static void 3149 objlist_push_head(Objlist *list, Obj_Entry *obj) 3150 { 3151 Objlist_Entry *elm; 3152 3153 elm = NEW(Objlist_Entry); 3154 elm->obj = obj; 3155 STAILQ_INSERT_HEAD(list, elm, link); 3156 } 3157 3158 static void 3159 objlist_push_tail(Objlist *list, Obj_Entry *obj) 3160 { 3161 Objlist_Entry *elm; 3162 3163 elm = NEW(Objlist_Entry); 3164 elm->obj = obj; 3165 STAILQ_INSERT_TAIL(list, elm, link); 3166 } 3167 3168 static void 3169 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 3170 { 3171 Objlist_Entry *elm, *listelm; 3172 3173 STAILQ_FOREACH(listelm, list, link) { 3174 if (listelm->obj == listobj) 3175 break; 3176 } 3177 elm = NEW(Objlist_Entry); 3178 elm->obj = obj; 3179 if (listelm != NULL) 3180 STAILQ_INSERT_AFTER(list, listelm, elm, link); 3181 else 3182 STAILQ_INSERT_TAIL(list, elm, link); 3183 } 3184 3185 static void 3186 objlist_remove(Objlist *list, Obj_Entry *obj) 3187 { 3188 Objlist_Entry *elm; 3189 3190 if ((elm = objlist_find(list, obj)) != NULL) { 3191 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 3192 free(elm); 3193 } 3194 } 3195 3196 /* 3197 * Relocate dag rooted in the specified object. 3198 * Returns 0 on success, or -1 on failure. 3199 */ 3200 3201 static int 3202 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 3203 int flags, RtldLockState *lockstate) 3204 { 3205 Objlist_Entry *elm; 3206 int error; 3207 3208 error = 0; 3209 STAILQ_FOREACH(elm, &root->dagmembers, link) { 3210 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 3211 lockstate); 3212 if (error == -1) 3213 break; 3214 } 3215 return (error); 3216 } 3217 3218 /* 3219 * Prepare for, or clean after, relocating an object marked with 3220 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 3221 * segments are remapped read-write. After relocations are done, the 3222 * segment's permissions are returned back to the modes specified in 3223 * the phdrs. If any relocation happened, or always for wired 3224 * program, COW is triggered. 3225 */ 3226 static int 3227 reloc_textrel_prot(Obj_Entry *obj, bool before) 3228 { 3229 const Elf_Phdr *ph; 3230 void *base; 3231 size_t l, sz; 3232 int prot; 3233 3234 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 3235 l--, ph++) { 3236 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 3237 continue; 3238 base = obj->relocbase + trunc_page(ph->p_vaddr); 3239 sz = round_page(ph->p_vaddr + ph->p_filesz) - 3240 trunc_page(ph->p_vaddr); 3241 prot = before ? (PROT_READ | PROT_WRITE) : 3242 convert_prot(ph->p_flags); 3243 if (mprotect(base, sz, prot) == -1) { 3244 _rtld_error("%s: Cannot write-%sable text segment: %s", 3245 obj->path, before ? "en" : "dis", 3246 rtld_strerror(errno)); 3247 return (-1); 3248 } 3249 } 3250 return (0); 3251 } 3252 3253 /* Process RELR relative relocations. */ 3254 static void 3255 reloc_relr(Obj_Entry *obj) 3256 { 3257 const Elf_Relr *relr, *relrlim; 3258 Elf_Addr *where; 3259 3260 relrlim = (const Elf_Relr *)((const char *)obj->relr + obj->relrsize); 3261 for (relr = obj->relr; relr < relrlim; relr++) { 3262 Elf_Relr entry = *relr; 3263 3264 if ((entry & 1) == 0) { 3265 where = (Elf_Addr *)(obj->relocbase + entry); 3266 *where++ += (Elf_Addr)obj->relocbase; 3267 } else { 3268 for (long i = 0; (entry >>= 1) != 0; i++) 3269 if ((entry & 1) != 0) 3270 where[i] += (Elf_Addr)obj->relocbase; 3271 where += CHAR_BIT * sizeof(Elf_Relr) - 1; 3272 } 3273 } 3274 } 3275 3276 /* 3277 * Relocate single object. 3278 * Returns 0 on success, or -1 on failure. 3279 */ 3280 static int 3281 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 3282 int flags, RtldLockState *lockstate) 3283 { 3284 3285 if (obj->relocated) 3286 return (0); 3287 obj->relocated = true; 3288 if (obj != rtldobj) 3289 dbg("relocating \"%s\"", obj->path); 3290 3291 if (obj->symtab == NULL || obj->strtab == NULL || 3292 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) 3293 dbg("object %s has no run-time symbol table", obj->path); 3294 3295 /* There are relocations to the write-protected text segment. */ 3296 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 3297 return (-1); 3298 3299 /* Process the non-PLT non-IFUNC relocations. */ 3300 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 3301 return (-1); 3302 reloc_relr(obj); 3303 3304 /* Re-protected the text segment. */ 3305 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 3306 return (-1); 3307 3308 /* Set the special PLT or GOT entries. */ 3309 init_pltgot(obj); 3310 3311 /* Process the PLT relocations. */ 3312 if (reloc_plt(obj, flags, lockstate) == -1) 3313 return (-1); 3314 /* Relocate the jump slots if we are doing immediate binding. */ 3315 if ((obj->bind_now || bind_now) && reloc_jmpslots(obj, flags, 3316 lockstate) == -1) 3317 return (-1); 3318 3319 if (!obj->mainprog && obj_enforce_relro(obj) == -1) 3320 return (-1); 3321 3322 /* 3323 * Set up the magic number and version in the Obj_Entry. These 3324 * were checked in the crt1.o from the original ElfKit, so we 3325 * set them for backward compatibility. 3326 */ 3327 obj->magic = RTLD_MAGIC; 3328 obj->version = RTLD_VERSION; 3329 3330 return (0); 3331 } 3332 3333 /* 3334 * Relocate newly-loaded shared objects. The argument is a pointer to 3335 * the Obj_Entry for the first such object. All objects from the first 3336 * to the end of the list of objects are relocated. Returns 0 on success, 3337 * or -1 on failure. 3338 */ 3339 static int 3340 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 3341 int flags, RtldLockState *lockstate) 3342 { 3343 Obj_Entry *obj; 3344 int error; 3345 3346 for (error = 0, obj = first; obj != NULL; 3347 obj = TAILQ_NEXT(obj, next)) { 3348 if (obj->marker) 3349 continue; 3350 error = relocate_object(obj, bind_now, rtldobj, flags, 3351 lockstate); 3352 if (error == -1) 3353 break; 3354 } 3355 return (error); 3356 } 3357 3358 /* 3359 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 3360 * referencing STT_GNU_IFUNC symbols is postponed till the other 3361 * relocations are done. The indirect functions specified as 3362 * ifunc are allowed to call other symbols, so we need to have 3363 * objects relocated before asking for resolution from indirects. 3364 * 3365 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 3366 * instead of the usual lazy handling of PLT slots. It is 3367 * consistent with how GNU does it. 3368 */ 3369 static int 3370 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 3371 RtldLockState *lockstate) 3372 { 3373 3374 if (obj->ifuncs_resolved) 3375 return (0); 3376 obj->ifuncs_resolved = true; 3377 if (!obj->irelative && !obj->irelative_nonplt && 3378 !((obj->bind_now || bind_now) && obj->gnu_ifunc) && 3379 !obj->non_plt_gnu_ifunc) 3380 return (0); 3381 if (obj_disable_relro(obj) == -1 || 3382 (obj->irelative && reloc_iresolve(obj, lockstate) == -1) || 3383 (obj->irelative_nonplt && reloc_iresolve_nonplt(obj, 3384 lockstate) == -1) || 3385 ((obj->bind_now || bind_now) && obj->gnu_ifunc && 3386 reloc_gnu_ifunc(obj, flags, lockstate) == -1) || 3387 (obj->non_plt_gnu_ifunc && reloc_non_plt(obj, &obj_rtld, 3388 flags | SYMLOOK_IFUNC, lockstate) == -1) || 3389 obj_enforce_relro(obj) == -1) 3390 return (-1); 3391 return (0); 3392 } 3393 3394 static int 3395 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 3396 RtldLockState *lockstate) 3397 { 3398 Objlist_Entry *elm; 3399 Obj_Entry *obj; 3400 3401 STAILQ_FOREACH(elm, list, link) { 3402 obj = elm->obj; 3403 if (obj->marker) 3404 continue; 3405 if (resolve_object_ifunc(obj, bind_now, flags, 3406 lockstate) == -1) 3407 return (-1); 3408 } 3409 return (0); 3410 } 3411 3412 /* 3413 * Cleanup procedure. It will be called (by the atexit mechanism) just 3414 * before the process exits. 3415 */ 3416 static void 3417 rtld_exit(void) 3418 { 3419 RtldLockState lockstate; 3420 3421 wlock_acquire(rtld_bind_lock, &lockstate); 3422 dbg("rtld_exit()"); 3423 objlist_call_fini(&list_fini, NULL, &lockstate); 3424 /* No need to remove the items from the list, since we are exiting. */ 3425 if (!libmap_disable) 3426 lm_fini(); 3427 lock_release(rtld_bind_lock, &lockstate); 3428 } 3429 3430 static void 3431 rtld_nop_exit(void) 3432 { 3433 } 3434 3435 /* 3436 * Iterate over a search path, translate each element, and invoke the 3437 * callback on the result. 3438 */ 3439 static void * 3440 path_enumerate(const char *path, path_enum_proc callback, 3441 const char *refobj_path, void *arg) 3442 { 3443 const char *trans; 3444 if (path == NULL) 3445 return (NULL); 3446 3447 path += strspn(path, ":;"); 3448 while (*path != '\0') { 3449 size_t len; 3450 char *res; 3451 3452 len = strcspn(path, ":;"); 3453 trans = lm_findn(refobj_path, path, len); 3454 if (trans) 3455 res = callback(trans, strlen(trans), arg); 3456 else 3457 res = callback(path, len, arg); 3458 3459 if (res != NULL) 3460 return (res); 3461 3462 path += len; 3463 path += strspn(path, ":;"); 3464 } 3465 3466 return (NULL); 3467 } 3468 3469 struct try_library_args { 3470 const char *name; 3471 size_t namelen; 3472 char *buffer; 3473 size_t buflen; 3474 int fd; 3475 }; 3476 3477 static void * 3478 try_library_path(const char *dir, size_t dirlen, void *param) 3479 { 3480 struct try_library_args *arg; 3481 int fd; 3482 3483 arg = param; 3484 if (*dir == '/' || trust) { 3485 char *pathname; 3486 3487 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 3488 return (NULL); 3489 3490 pathname = arg->buffer; 3491 strncpy(pathname, dir, dirlen); 3492 pathname[dirlen] = '/'; 3493 strcpy(pathname + dirlen + 1, arg->name); 3494 3495 dbg(" Trying \"%s\"", pathname); 3496 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY); 3497 if (fd >= 0) { 3498 dbg(" Opened \"%s\", fd %d", pathname, fd); 3499 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 3500 strcpy(pathname, arg->buffer); 3501 arg->fd = fd; 3502 return (pathname); 3503 } else { 3504 dbg(" Failed to open \"%s\": %s", 3505 pathname, rtld_strerror(errno)); 3506 } 3507 } 3508 return (NULL); 3509 } 3510 3511 static char * 3512 search_library_path(const char *name, const char *path, 3513 const char *refobj_path, int *fdp) 3514 { 3515 char *p; 3516 struct try_library_args arg; 3517 3518 if (path == NULL) 3519 return (NULL); 3520 3521 arg.name = name; 3522 arg.namelen = strlen(name); 3523 arg.buffer = xmalloc(PATH_MAX); 3524 arg.buflen = PATH_MAX; 3525 arg.fd = -1; 3526 3527 p = path_enumerate(path, try_library_path, refobj_path, &arg); 3528 *fdp = arg.fd; 3529 3530 free(arg.buffer); 3531 3532 return (p); 3533 } 3534 3535 3536 /* 3537 * Finds the library with the given name using the directory descriptors 3538 * listed in the LD_LIBRARY_PATH_FDS environment variable. 3539 * 3540 * Returns a freshly-opened close-on-exec file descriptor for the library, 3541 * or -1 if the library cannot be found. 3542 */ 3543 static char * 3544 search_library_pathfds(const char *name, const char *path, int *fdp) 3545 { 3546 char *envcopy, *fdstr, *found, *last_token; 3547 size_t len; 3548 int dirfd, fd; 3549 3550 dbg("%s('%s', '%s', fdp)", __func__, name, path); 3551 3552 /* Don't load from user-specified libdirs into setuid binaries. */ 3553 if (!trust) 3554 return (NULL); 3555 3556 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 3557 if (path == NULL) 3558 return (NULL); 3559 3560 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 3561 if (name[0] == '/') { 3562 dbg("Absolute path (%s) passed to %s", name, __func__); 3563 return (NULL); 3564 } 3565 3566 /* 3567 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 3568 * copy of the path, as strtok_r rewrites separator tokens 3569 * with '\0'. 3570 */ 3571 found = NULL; 3572 envcopy = xstrdup(path); 3573 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 3574 fdstr = strtok_r(NULL, ":", &last_token)) { 3575 dirfd = parse_integer(fdstr); 3576 if (dirfd < 0) { 3577 _rtld_error("failed to parse directory FD: '%s'", 3578 fdstr); 3579 break; 3580 } 3581 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 3582 if (fd >= 0) { 3583 *fdp = fd; 3584 len = strlen(fdstr) + strlen(name) + 3; 3585 found = xmalloc(len); 3586 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 3587 _rtld_error("error generating '%d/%s'", 3588 dirfd, name); 3589 rtld_die(); 3590 } 3591 dbg("open('%s') => %d", found, fd); 3592 break; 3593 } 3594 } 3595 free(envcopy); 3596 3597 return (found); 3598 } 3599 3600 3601 int 3602 dlclose(void *handle) 3603 { 3604 RtldLockState lockstate; 3605 int error; 3606 3607 wlock_acquire(rtld_bind_lock, &lockstate); 3608 error = dlclose_locked(handle, &lockstate); 3609 lock_release(rtld_bind_lock, &lockstate); 3610 return (error); 3611 } 3612 3613 static int 3614 dlclose_locked(void *handle, RtldLockState *lockstate) 3615 { 3616 Obj_Entry *root; 3617 3618 root = dlcheck(handle); 3619 if (root == NULL) 3620 return (-1); 3621 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 3622 root->path); 3623 3624 /* Unreference the object and its dependencies. */ 3625 root->dl_refcount--; 3626 3627 if (root->refcount == 1) { 3628 /* 3629 * The object will be no longer referenced, so we must unload it. 3630 * First, call the fini functions. 3631 */ 3632 objlist_call_fini(&list_fini, root, lockstate); 3633 3634 unref_dag(root); 3635 3636 /* Finish cleaning up the newly-unreferenced objects. */ 3637 GDB_STATE(RT_DELETE,&root->linkmap); 3638 unload_object(root, lockstate); 3639 GDB_STATE(RT_CONSISTENT,NULL); 3640 } else 3641 unref_dag(root); 3642 3643 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 3644 return (0); 3645 } 3646 3647 char * 3648 dlerror(void) 3649 { 3650 if (*(lockinfo.dlerror_seen()) != 0) 3651 return (NULL); 3652 *lockinfo.dlerror_seen() = 1; 3653 return (lockinfo.dlerror_loc()); 3654 } 3655 3656 /* 3657 * This function is deprecated and has no effect. 3658 */ 3659 void 3660 dllockinit(void *context, 3661 void *(*_lock_create)(void *context) __unused, 3662 void (*_rlock_acquire)(void *lock) __unused, 3663 void (*_wlock_acquire)(void *lock) __unused, 3664 void (*_lock_release)(void *lock) __unused, 3665 void (*_lock_destroy)(void *lock) __unused, 3666 void (*context_destroy)(void *context)) 3667 { 3668 static void *cur_context; 3669 static void (*cur_context_destroy)(void *); 3670 3671 /* Just destroy the context from the previous call, if necessary. */ 3672 if (cur_context_destroy != NULL) 3673 cur_context_destroy(cur_context); 3674 cur_context = context; 3675 cur_context_destroy = context_destroy; 3676 } 3677 3678 void * 3679 dlopen(const char *name, int mode) 3680 { 3681 3682 return (rtld_dlopen(name, -1, mode)); 3683 } 3684 3685 void * 3686 fdlopen(int fd, int mode) 3687 { 3688 3689 return (rtld_dlopen(NULL, fd, mode)); 3690 } 3691 3692 static void * 3693 rtld_dlopen(const char *name, int fd, int mode) 3694 { 3695 RtldLockState lockstate; 3696 int lo_flags; 3697 3698 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3699 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3700 if (ld_tracing != NULL) { 3701 rlock_acquire(rtld_bind_lock, &lockstate); 3702 if (sigsetjmp(lockstate.env, 0) != 0) 3703 lock_upgrade(rtld_bind_lock, &lockstate); 3704 environ = __DECONST(char **, *get_program_var_addr("environ", &lockstate)); 3705 lock_release(rtld_bind_lock, &lockstate); 3706 } 3707 lo_flags = RTLD_LO_DLOPEN; 3708 if (mode & RTLD_NODELETE) 3709 lo_flags |= RTLD_LO_NODELETE; 3710 if (mode & RTLD_NOLOAD) 3711 lo_flags |= RTLD_LO_NOLOAD; 3712 if (mode & RTLD_DEEPBIND) 3713 lo_flags |= RTLD_LO_DEEPBIND; 3714 if (ld_tracing != NULL) 3715 lo_flags |= RTLD_LO_TRACE | RTLD_LO_IGNSTLS; 3716 3717 return (dlopen_object(name, fd, obj_main, lo_flags, 3718 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3719 } 3720 3721 static void 3722 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate) 3723 { 3724 3725 obj->dl_refcount--; 3726 unref_dag(obj); 3727 if (obj->refcount == 0) 3728 unload_object(obj, lockstate); 3729 } 3730 3731 static Obj_Entry * 3732 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3733 int mode, RtldLockState *lockstate) 3734 { 3735 Obj_Entry *old_obj_tail; 3736 Obj_Entry *obj; 3737 Objlist initlist; 3738 RtldLockState mlockstate; 3739 int result; 3740 3741 dbg("dlopen_object name \"%s\" fd %d refobj \"%s\" lo_flags %#x mode %#x", 3742 name != NULL ? name : "<null>", fd, refobj == NULL ? "<null>" : 3743 refobj->path, lo_flags, mode); 3744 objlist_init(&initlist); 3745 3746 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3747 wlock_acquire(rtld_bind_lock, &mlockstate); 3748 lockstate = &mlockstate; 3749 } 3750 GDB_STATE(RT_ADD,NULL); 3751 3752 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 3753 obj = NULL; 3754 if (name == NULL && fd == -1) { 3755 obj = obj_main; 3756 obj->refcount++; 3757 } else { 3758 obj = load_object(name, fd, refobj, lo_flags); 3759 } 3760 3761 if (obj) { 3762 obj->dl_refcount++; 3763 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3764 objlist_push_tail(&list_global, obj); 3765 if (globallist_next(old_obj_tail) != NULL) { 3766 /* We loaded something new. */ 3767 assert(globallist_next(old_obj_tail) == obj); 3768 if ((lo_flags & RTLD_LO_DEEPBIND) != 0) 3769 obj->symbolic = true; 3770 result = 0; 3771 if ((lo_flags & (RTLD_LO_EARLY | RTLD_LO_IGNSTLS)) == 0 && 3772 obj->static_tls && !allocate_tls_offset(obj)) { 3773 _rtld_error("%s: No space available " 3774 "for static Thread Local Storage", obj->path); 3775 result = -1; 3776 } 3777 if (result != -1) 3778 result = load_needed_objects(obj, lo_flags & (RTLD_LO_DLOPEN | 3779 RTLD_LO_EARLY | RTLD_LO_IGNSTLS | RTLD_LO_TRACE)); 3780 init_dag(obj); 3781 ref_dag(obj); 3782 if (result != -1) 3783 result = rtld_verify_versions(&obj->dagmembers); 3784 if (result != -1 && ld_tracing) 3785 goto trace; 3786 if (result == -1 || relocate_object_dag(obj, 3787 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3788 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3789 lockstate) == -1) { 3790 dlopen_cleanup(obj, lockstate); 3791 obj = NULL; 3792 } else if (lo_flags & RTLD_LO_EARLY) { 3793 /* 3794 * Do not call the init functions for early loaded 3795 * filtees. The image is still not initialized enough 3796 * for them to work. 3797 * 3798 * Our object is found by the global object list and 3799 * will be ordered among all init calls done right 3800 * before transferring control to main. 3801 */ 3802 } else { 3803 /* Make list of init functions to call. */ 3804 initlist_add_objects(obj, obj, &initlist); 3805 } 3806 /* 3807 * Process all no_delete or global objects here, given 3808 * them own DAGs to prevent their dependencies from being 3809 * unloaded. This has to be done after we have loaded all 3810 * of the dependencies, so that we do not miss any. 3811 */ 3812 if (obj != NULL) 3813 process_z(obj); 3814 } else { 3815 /* 3816 * Bump the reference counts for objects on this DAG. If 3817 * this is the first dlopen() call for the object that was 3818 * already loaded as a dependency, initialize the dag 3819 * starting at it. 3820 */ 3821 init_dag(obj); 3822 ref_dag(obj); 3823 3824 if ((lo_flags & RTLD_LO_TRACE) != 0) 3825 goto trace; 3826 } 3827 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3828 obj->z_nodelete) && !obj->ref_nodel) { 3829 dbg("obj %s nodelete", obj->path); 3830 ref_dag(obj); 3831 obj->z_nodelete = obj->ref_nodel = true; 3832 } 3833 } 3834 3835 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3836 name); 3837 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3838 3839 if ((lo_flags & RTLD_LO_EARLY) == 0) { 3840 map_stacks_exec(lockstate); 3841 if (obj != NULL) 3842 distribute_static_tls(&initlist, lockstate); 3843 } 3844 3845 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3846 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3847 lockstate) == -1) { 3848 objlist_clear(&initlist); 3849 dlopen_cleanup(obj, lockstate); 3850 if (lockstate == &mlockstate) 3851 lock_release(rtld_bind_lock, lockstate); 3852 return (NULL); 3853 } 3854 3855 if (!(lo_flags & RTLD_LO_EARLY)) { 3856 /* Call the init functions. */ 3857 objlist_call_init(&initlist, lockstate); 3858 } 3859 objlist_clear(&initlist); 3860 if (lockstate == &mlockstate) 3861 lock_release(rtld_bind_lock, lockstate); 3862 return (obj); 3863 trace: 3864 trace_loaded_objects(obj); 3865 if (lockstate == &mlockstate) 3866 lock_release(rtld_bind_lock, lockstate); 3867 exit(0); 3868 } 3869 3870 static void * 3871 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3872 int flags) 3873 { 3874 DoneList donelist; 3875 const Obj_Entry *obj, *defobj; 3876 const Elf_Sym *def; 3877 SymLook req; 3878 RtldLockState lockstate; 3879 tls_index ti; 3880 void *sym; 3881 int res; 3882 3883 def = NULL; 3884 defobj = NULL; 3885 symlook_init(&req, name); 3886 req.ventry = ve; 3887 req.flags = flags | SYMLOOK_IN_PLT; 3888 req.lockstate = &lockstate; 3889 3890 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3891 rlock_acquire(rtld_bind_lock, &lockstate); 3892 if (sigsetjmp(lockstate.env, 0) != 0) 3893 lock_upgrade(rtld_bind_lock, &lockstate); 3894 if (handle == NULL || handle == RTLD_NEXT || 3895 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3896 3897 if ((obj = obj_from_addr(retaddr)) == NULL) { 3898 _rtld_error("Cannot determine caller's shared object"); 3899 lock_release(rtld_bind_lock, &lockstate); 3900 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3901 return (NULL); 3902 } 3903 if (handle == NULL) { /* Just the caller's shared object. */ 3904 res = symlook_obj(&req, obj); 3905 if (res == 0) { 3906 def = req.sym_out; 3907 defobj = req.defobj_out; 3908 } 3909 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3910 handle == RTLD_SELF) { /* ... caller included */ 3911 if (handle == RTLD_NEXT) 3912 obj = globallist_next(obj); 3913 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3914 if (obj->marker) 3915 continue; 3916 res = symlook_obj(&req, obj); 3917 if (res == 0) { 3918 if (def == NULL || (ld_dynamic_weak && 3919 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK)) { 3920 def = req.sym_out; 3921 defobj = req.defobj_out; 3922 if (!ld_dynamic_weak || 3923 ELF_ST_BIND(def->st_info) != STB_WEAK) 3924 break; 3925 } 3926 } 3927 } 3928 /* 3929 * Search the dynamic linker itself, and possibly resolve the 3930 * symbol from there. This is how the application links to 3931 * dynamic linker services such as dlopen. 3932 * Note that we ignore ld_dynamic_weak == false case, 3933 * always overriding weak symbols by rtld definitions. 3934 */ 3935 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3936 res = symlook_obj(&req, &obj_rtld); 3937 if (res == 0) { 3938 def = req.sym_out; 3939 defobj = req.defobj_out; 3940 } 3941 } 3942 } else { 3943 assert(handle == RTLD_DEFAULT); 3944 res = symlook_default(&req, obj); 3945 if (res == 0) { 3946 defobj = req.defobj_out; 3947 def = req.sym_out; 3948 } 3949 } 3950 } else { 3951 if ((obj = dlcheck(handle)) == NULL) { 3952 lock_release(rtld_bind_lock, &lockstate); 3953 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3954 return (NULL); 3955 } 3956 3957 donelist_init(&donelist); 3958 if (obj->mainprog) { 3959 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3960 res = symlook_global(&req, &donelist); 3961 if (res == 0) { 3962 def = req.sym_out; 3963 defobj = req.defobj_out; 3964 } 3965 /* 3966 * Search the dynamic linker itself, and possibly resolve the 3967 * symbol from there. This is how the application links to 3968 * dynamic linker services such as dlopen. 3969 */ 3970 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3971 res = symlook_obj(&req, &obj_rtld); 3972 if (res == 0) { 3973 def = req.sym_out; 3974 defobj = req.defobj_out; 3975 } 3976 } 3977 } 3978 else { 3979 /* Search the whole DAG rooted at the given object. */ 3980 res = symlook_list(&req, &obj->dagmembers, &donelist); 3981 if (res == 0) { 3982 def = req.sym_out; 3983 defobj = req.defobj_out; 3984 } 3985 } 3986 } 3987 3988 if (def != NULL) { 3989 lock_release(rtld_bind_lock, &lockstate); 3990 3991 /* 3992 * The value required by the caller is derived from the value 3993 * of the symbol. this is simply the relocated value of the 3994 * symbol. 3995 */ 3996 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3997 sym = make_function_pointer(def, defobj); 3998 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3999 sym = rtld_resolve_ifunc(defobj, def); 4000 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 4001 ti.ti_module = defobj->tlsindex; 4002 ti.ti_offset = def->st_value; 4003 sym = __tls_get_addr(&ti); 4004 } else 4005 sym = defobj->relocbase + def->st_value; 4006 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 4007 return (sym); 4008 } 4009 4010 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "", 4011 ve != NULL ? ve->name : ""); 4012 lock_release(rtld_bind_lock, &lockstate); 4013 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 4014 return (NULL); 4015 } 4016 4017 void * 4018 dlsym(void *handle, const char *name) 4019 { 4020 return (do_dlsym(handle, name, __builtin_return_address(0), NULL, 4021 SYMLOOK_DLSYM)); 4022 } 4023 4024 dlfunc_t 4025 dlfunc(void *handle, const char *name) 4026 { 4027 union { 4028 void *d; 4029 dlfunc_t f; 4030 } rv; 4031 4032 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 4033 SYMLOOK_DLSYM); 4034 return (rv.f); 4035 } 4036 4037 void * 4038 dlvsym(void *handle, const char *name, const char *version) 4039 { 4040 Ver_Entry ventry; 4041 4042 ventry.name = version; 4043 ventry.file = NULL; 4044 ventry.hash = elf_hash(version); 4045 ventry.flags= 0; 4046 return (do_dlsym(handle, name, __builtin_return_address(0), &ventry, 4047 SYMLOOK_DLSYM)); 4048 } 4049 4050 int 4051 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 4052 { 4053 const Obj_Entry *obj; 4054 RtldLockState lockstate; 4055 4056 rlock_acquire(rtld_bind_lock, &lockstate); 4057 obj = obj_from_addr(addr); 4058 if (obj == NULL) { 4059 _rtld_error("No shared object contains address"); 4060 lock_release(rtld_bind_lock, &lockstate); 4061 return (0); 4062 } 4063 rtld_fill_dl_phdr_info(obj, phdr_info); 4064 lock_release(rtld_bind_lock, &lockstate); 4065 return (1); 4066 } 4067 4068 int 4069 dladdr(const void *addr, Dl_info *info) 4070 { 4071 const Obj_Entry *obj; 4072 const Elf_Sym *def; 4073 void *symbol_addr; 4074 unsigned long symoffset; 4075 RtldLockState lockstate; 4076 4077 rlock_acquire(rtld_bind_lock, &lockstate); 4078 obj = obj_from_addr(addr); 4079 if (obj == NULL) { 4080 _rtld_error("No shared object contains address"); 4081 lock_release(rtld_bind_lock, &lockstate); 4082 return (0); 4083 } 4084 info->dli_fname = obj->path; 4085 info->dli_fbase = obj->mapbase; 4086 info->dli_saddr = (void *)0; 4087 info->dli_sname = NULL; 4088 4089 /* 4090 * Walk the symbol list looking for the symbol whose address is 4091 * closest to the address sent in. 4092 */ 4093 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 4094 def = obj->symtab + symoffset; 4095 4096 /* 4097 * For skip the symbol if st_shndx is either SHN_UNDEF or 4098 * SHN_COMMON. 4099 */ 4100 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 4101 continue; 4102 4103 /* 4104 * If the symbol is greater than the specified address, or if it 4105 * is further away from addr than the current nearest symbol, 4106 * then reject it. 4107 */ 4108 symbol_addr = obj->relocbase + def->st_value; 4109 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 4110 continue; 4111 4112 /* Update our idea of the nearest symbol. */ 4113 info->dli_sname = obj->strtab + def->st_name; 4114 info->dli_saddr = symbol_addr; 4115 4116 /* Exact match? */ 4117 if (info->dli_saddr == addr) 4118 break; 4119 } 4120 lock_release(rtld_bind_lock, &lockstate); 4121 return (1); 4122 } 4123 4124 int 4125 dlinfo(void *handle, int request, void *p) 4126 { 4127 const Obj_Entry *obj; 4128 RtldLockState lockstate; 4129 int error; 4130 4131 rlock_acquire(rtld_bind_lock, &lockstate); 4132 4133 if (handle == NULL || handle == RTLD_SELF) { 4134 void *retaddr; 4135 4136 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 4137 if ((obj = obj_from_addr(retaddr)) == NULL) 4138 _rtld_error("Cannot determine caller's shared object"); 4139 } else 4140 obj = dlcheck(handle); 4141 4142 if (obj == NULL) { 4143 lock_release(rtld_bind_lock, &lockstate); 4144 return (-1); 4145 } 4146 4147 error = 0; 4148 switch (request) { 4149 case RTLD_DI_LINKMAP: 4150 *((struct link_map const **)p) = &obj->linkmap; 4151 break; 4152 case RTLD_DI_ORIGIN: 4153 error = rtld_dirname(obj->path, p); 4154 break; 4155 4156 case RTLD_DI_SERINFOSIZE: 4157 case RTLD_DI_SERINFO: 4158 error = do_search_info(obj, request, (struct dl_serinfo *)p); 4159 break; 4160 4161 default: 4162 _rtld_error("Invalid request %d passed to dlinfo()", request); 4163 error = -1; 4164 } 4165 4166 lock_release(rtld_bind_lock, &lockstate); 4167 4168 return (error); 4169 } 4170 4171 static void 4172 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 4173 { 4174 uintptr_t **dtvp; 4175 4176 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 4177 phdr_info->dlpi_name = obj->path; 4178 phdr_info->dlpi_phdr = obj->phdr; 4179 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 4180 phdr_info->dlpi_tls_modid = obj->tlsindex; 4181 dtvp = &_tcb_get()->tcb_dtv; 4182 phdr_info->dlpi_tls_data = (char *)tls_get_addr_slow(dtvp, 4183 obj->tlsindex, 0, true) + TLS_DTV_OFFSET; 4184 phdr_info->dlpi_adds = obj_loads; 4185 phdr_info->dlpi_subs = obj_loads - obj_count; 4186 } 4187 4188 int 4189 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 4190 { 4191 struct dl_phdr_info phdr_info; 4192 Obj_Entry *obj, marker; 4193 RtldLockState bind_lockstate, phdr_lockstate; 4194 int error; 4195 4196 init_marker(&marker); 4197 error = 0; 4198 4199 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 4200 wlock_acquire(rtld_bind_lock, &bind_lockstate); 4201 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 4202 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 4203 rtld_fill_dl_phdr_info(obj, &phdr_info); 4204 hold_object(obj); 4205 lock_release(rtld_bind_lock, &bind_lockstate); 4206 4207 error = callback(&phdr_info, sizeof phdr_info, param); 4208 4209 wlock_acquire(rtld_bind_lock, &bind_lockstate); 4210 unhold_object(obj); 4211 obj = globallist_next(&marker); 4212 TAILQ_REMOVE(&obj_list, &marker, next); 4213 if (error != 0) { 4214 lock_release(rtld_bind_lock, &bind_lockstate); 4215 lock_release(rtld_phdr_lock, &phdr_lockstate); 4216 return (error); 4217 } 4218 } 4219 4220 if (error == 0) { 4221 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 4222 lock_release(rtld_bind_lock, &bind_lockstate); 4223 error = callback(&phdr_info, sizeof(phdr_info), param); 4224 } 4225 lock_release(rtld_phdr_lock, &phdr_lockstate); 4226 return (error); 4227 } 4228 4229 static void * 4230 fill_search_info(const char *dir, size_t dirlen, void *param) 4231 { 4232 struct fill_search_info_args *arg; 4233 4234 arg = param; 4235 4236 if (arg->request == RTLD_DI_SERINFOSIZE) { 4237 arg->serinfo->dls_cnt ++; 4238 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 4239 } else { 4240 struct dl_serpath *s_entry; 4241 4242 s_entry = arg->serpath; 4243 s_entry->dls_name = arg->strspace; 4244 s_entry->dls_flags = arg->flags; 4245 4246 strncpy(arg->strspace, dir, dirlen); 4247 arg->strspace[dirlen] = '\0'; 4248 4249 arg->strspace += dirlen + 1; 4250 arg->serpath++; 4251 } 4252 4253 return (NULL); 4254 } 4255 4256 static int 4257 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 4258 { 4259 struct dl_serinfo _info; 4260 struct fill_search_info_args args; 4261 4262 args.request = RTLD_DI_SERINFOSIZE; 4263 args.serinfo = &_info; 4264 4265 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 4266 _info.dls_cnt = 0; 4267 4268 path_enumerate(obj->rpath, fill_search_info, NULL, &args); 4269 path_enumerate(ld_library_path, fill_search_info, NULL, &args); 4270 path_enumerate(obj->runpath, fill_search_info, NULL, &args); 4271 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args); 4272 if (!obj->z_nodeflib) 4273 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args); 4274 4275 4276 if (request == RTLD_DI_SERINFOSIZE) { 4277 info->dls_size = _info.dls_size; 4278 info->dls_cnt = _info.dls_cnt; 4279 return (0); 4280 } 4281 4282 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 4283 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 4284 return (-1); 4285 } 4286 4287 args.request = RTLD_DI_SERINFO; 4288 args.serinfo = info; 4289 args.serpath = &info->dls_serpath[0]; 4290 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 4291 4292 args.flags = LA_SER_RUNPATH; 4293 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL) 4294 return (-1); 4295 4296 args.flags = LA_SER_LIBPATH; 4297 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL) 4298 return (-1); 4299 4300 args.flags = LA_SER_RUNPATH; 4301 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL) 4302 return (-1); 4303 4304 args.flags = LA_SER_CONFIG; 4305 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args) 4306 != NULL) 4307 return (-1); 4308 4309 args.flags = LA_SER_DEFAULT; 4310 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path, 4311 fill_search_info, NULL, &args) != NULL) 4312 return (-1); 4313 return (0); 4314 } 4315 4316 static int 4317 rtld_dirname(const char *path, char *bname) 4318 { 4319 const char *endp; 4320 4321 /* Empty or NULL string gets treated as "." */ 4322 if (path == NULL || *path == '\0') { 4323 bname[0] = '.'; 4324 bname[1] = '\0'; 4325 return (0); 4326 } 4327 4328 /* Strip trailing slashes */ 4329 endp = path + strlen(path) - 1; 4330 while (endp > path && *endp == '/') 4331 endp--; 4332 4333 /* Find the start of the dir */ 4334 while (endp > path && *endp != '/') 4335 endp--; 4336 4337 /* Either the dir is "/" or there are no slashes */ 4338 if (endp == path) { 4339 bname[0] = *endp == '/' ? '/' : '.'; 4340 bname[1] = '\0'; 4341 return (0); 4342 } else { 4343 do { 4344 endp--; 4345 } while (endp > path && *endp == '/'); 4346 } 4347 4348 if (endp - path + 2 > PATH_MAX) 4349 { 4350 _rtld_error("Filename is too long: %s", path); 4351 return(-1); 4352 } 4353 4354 strncpy(bname, path, endp - path + 1); 4355 bname[endp - path + 1] = '\0'; 4356 return (0); 4357 } 4358 4359 static int 4360 rtld_dirname_abs(const char *path, char *base) 4361 { 4362 char *last; 4363 4364 if (realpath(path, base) == NULL) { 4365 _rtld_error("realpath \"%s\" failed (%s)", path, 4366 rtld_strerror(errno)); 4367 return (-1); 4368 } 4369 dbg("%s -> %s", path, base); 4370 last = strrchr(base, '/'); 4371 if (last == NULL) { 4372 _rtld_error("non-abs result from realpath \"%s\"", path); 4373 return (-1); 4374 } 4375 if (last != base) 4376 *last = '\0'; 4377 return (0); 4378 } 4379 4380 static void 4381 linkmap_add(Obj_Entry *obj) 4382 { 4383 struct link_map *l, *prev; 4384 4385 l = &obj->linkmap; 4386 l->l_name = obj->path; 4387 l->l_base = obj->mapbase; 4388 l->l_ld = obj->dynamic; 4389 l->l_addr = obj->relocbase; 4390 4391 if (r_debug.r_map == NULL) { 4392 r_debug.r_map = l; 4393 return; 4394 } 4395 4396 /* 4397 * Scan to the end of the list, but not past the entry for the 4398 * dynamic linker, which we want to keep at the very end. 4399 */ 4400 for (prev = r_debug.r_map; 4401 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 4402 prev = prev->l_next) 4403 ; 4404 4405 /* Link in the new entry. */ 4406 l->l_prev = prev; 4407 l->l_next = prev->l_next; 4408 if (l->l_next != NULL) 4409 l->l_next->l_prev = l; 4410 prev->l_next = l; 4411 } 4412 4413 static void 4414 linkmap_delete(Obj_Entry *obj) 4415 { 4416 struct link_map *l; 4417 4418 l = &obj->linkmap; 4419 if (l->l_prev == NULL) { 4420 if ((r_debug.r_map = l->l_next) != NULL) 4421 l->l_next->l_prev = NULL; 4422 return; 4423 } 4424 4425 if ((l->l_prev->l_next = l->l_next) != NULL) 4426 l->l_next->l_prev = l->l_prev; 4427 } 4428 4429 /* 4430 * Function for the debugger to set a breakpoint on to gain control. 4431 * 4432 * The two parameters allow the debugger to easily find and determine 4433 * what the runtime loader is doing and to whom it is doing it. 4434 * 4435 * When the loadhook trap is hit (r_debug_state, set at program 4436 * initialization), the arguments can be found on the stack: 4437 * 4438 * +8 struct link_map *m 4439 * +4 struct r_debug *rd 4440 * +0 RetAddr 4441 */ 4442 void 4443 r_debug_state(struct r_debug* rd __unused, struct link_map *m __unused) 4444 { 4445 /* 4446 * The following is a hack to force the compiler to emit calls to 4447 * this function, even when optimizing. If the function is empty, 4448 * the compiler is not obliged to emit any code for calls to it, 4449 * even when marked __noinline. However, gdb depends on those 4450 * calls being made. 4451 */ 4452 __compiler_membar(); 4453 } 4454 4455 /* 4456 * A function called after init routines have completed. This can be used to 4457 * break before a program's entry routine is called, and can be used when 4458 * main is not available in the symbol table. 4459 */ 4460 void 4461 _r_debug_postinit(struct link_map *m __unused) 4462 { 4463 4464 /* See r_debug_state(). */ 4465 __compiler_membar(); 4466 } 4467 4468 static void 4469 release_object(Obj_Entry *obj) 4470 { 4471 4472 if (obj->holdcount > 0) { 4473 obj->unholdfree = true; 4474 return; 4475 } 4476 munmap(obj->mapbase, obj->mapsize); 4477 linkmap_delete(obj); 4478 obj_free(obj); 4479 } 4480 4481 /* 4482 * Get address of the pointer variable in the main program. 4483 * Prefer non-weak symbol over the weak one. 4484 */ 4485 static const void ** 4486 get_program_var_addr(const char *name, RtldLockState *lockstate) 4487 { 4488 SymLook req; 4489 DoneList donelist; 4490 4491 symlook_init(&req, name); 4492 req.lockstate = lockstate; 4493 donelist_init(&donelist); 4494 if (symlook_global(&req, &donelist) != 0) 4495 return (NULL); 4496 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 4497 return ((const void **)make_function_pointer(req.sym_out, 4498 req.defobj_out)); 4499 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 4500 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 4501 else 4502 return ((const void **)(req.defobj_out->relocbase + 4503 req.sym_out->st_value)); 4504 } 4505 4506 /* 4507 * Set a pointer variable in the main program to the given value. This 4508 * is used to set key variables such as "environ" before any of the 4509 * init functions are called. 4510 */ 4511 static void 4512 set_program_var(const char *name, const void *value) 4513 { 4514 const void **addr; 4515 4516 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 4517 dbg("\"%s\": *%p <-- %p", name, addr, value); 4518 *addr = value; 4519 } 4520 } 4521 4522 /* 4523 * Search the global objects, including dependencies and main object, 4524 * for the given symbol. 4525 */ 4526 static int 4527 symlook_global(SymLook *req, DoneList *donelist) 4528 { 4529 SymLook req1; 4530 const Objlist_Entry *elm; 4531 int res; 4532 4533 symlook_init_from_req(&req1, req); 4534 4535 /* Search all objects loaded at program start up. */ 4536 if (req->defobj_out == NULL || (ld_dynamic_weak && 4537 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK)) { 4538 res = symlook_list(&req1, &list_main, donelist); 4539 if (res == 0 && (!ld_dynamic_weak || req->defobj_out == NULL || 4540 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4541 req->sym_out = req1.sym_out; 4542 req->defobj_out = req1.defobj_out; 4543 assert(req->defobj_out != NULL); 4544 } 4545 } 4546 4547 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 4548 STAILQ_FOREACH(elm, &list_global, link) { 4549 if (req->defobj_out != NULL && (!ld_dynamic_weak || 4550 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)) 4551 break; 4552 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 4553 if (res == 0 && (req->defobj_out == NULL || 4554 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4555 req->sym_out = req1.sym_out; 4556 req->defobj_out = req1.defobj_out; 4557 assert(req->defobj_out != NULL); 4558 } 4559 } 4560 4561 return (req->sym_out != NULL ? 0 : ESRCH); 4562 } 4563 4564 /* 4565 * Given a symbol name in a referencing object, find the corresponding 4566 * definition of the symbol. Returns a pointer to the symbol, or NULL if 4567 * no definition was found. Returns a pointer to the Obj_Entry of the 4568 * defining object via the reference parameter DEFOBJ_OUT. 4569 */ 4570 static int 4571 symlook_default(SymLook *req, const Obj_Entry *refobj) 4572 { 4573 DoneList donelist; 4574 const Objlist_Entry *elm; 4575 SymLook req1; 4576 int res; 4577 4578 donelist_init(&donelist); 4579 symlook_init_from_req(&req1, req); 4580 4581 /* 4582 * Look first in the referencing object if linked symbolically, 4583 * and similarly handle protected symbols. 4584 */ 4585 res = symlook_obj(&req1, refobj); 4586 if (res == 0 && (refobj->symbolic || 4587 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) { 4588 req->sym_out = req1.sym_out; 4589 req->defobj_out = req1.defobj_out; 4590 assert(req->defobj_out != NULL); 4591 } 4592 if (refobj->symbolic || req->defobj_out != NULL) 4593 donelist_check(&donelist, refobj); 4594 4595 symlook_global(req, &donelist); 4596 4597 /* Search all dlopened DAGs containing the referencing object. */ 4598 STAILQ_FOREACH(elm, &refobj->dldags, link) { 4599 if (req->sym_out != NULL && (!ld_dynamic_weak || 4600 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)) 4601 break; 4602 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 4603 if (res == 0 && (req->sym_out == NULL || 4604 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4605 req->sym_out = req1.sym_out; 4606 req->defobj_out = req1.defobj_out; 4607 assert(req->defobj_out != NULL); 4608 } 4609 } 4610 4611 /* 4612 * Search the dynamic linker itself, and possibly resolve the 4613 * symbol from there. This is how the application links to 4614 * dynamic linker services such as dlopen. 4615 */ 4616 if (req->sym_out == NULL || 4617 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4618 res = symlook_obj(&req1, &obj_rtld); 4619 if (res == 0) { 4620 req->sym_out = req1.sym_out; 4621 req->defobj_out = req1.defobj_out; 4622 assert(req->defobj_out != NULL); 4623 } 4624 } 4625 4626 return (req->sym_out != NULL ? 0 : ESRCH); 4627 } 4628 4629 static int 4630 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 4631 { 4632 const Elf_Sym *def; 4633 const Obj_Entry *defobj; 4634 const Objlist_Entry *elm; 4635 SymLook req1; 4636 int res; 4637 4638 def = NULL; 4639 defobj = NULL; 4640 STAILQ_FOREACH(elm, objlist, link) { 4641 if (donelist_check(dlp, elm->obj)) 4642 continue; 4643 symlook_init_from_req(&req1, req); 4644 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 4645 if (def == NULL || (ld_dynamic_weak && 4646 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4647 def = req1.sym_out; 4648 defobj = req1.defobj_out; 4649 if (!ld_dynamic_weak || ELF_ST_BIND(def->st_info) != STB_WEAK) 4650 break; 4651 } 4652 } 4653 } 4654 if (def != NULL) { 4655 req->sym_out = def; 4656 req->defobj_out = defobj; 4657 return (0); 4658 } 4659 return (ESRCH); 4660 } 4661 4662 /* 4663 * Search the chain of DAGS cointed to by the given Needed_Entry 4664 * for a symbol of the given name. Each DAG is scanned completely 4665 * before advancing to the next one. Returns a pointer to the symbol, 4666 * or NULL if no definition was found. 4667 */ 4668 static int 4669 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 4670 { 4671 const Elf_Sym *def; 4672 const Needed_Entry *n; 4673 const Obj_Entry *defobj; 4674 SymLook req1; 4675 int res; 4676 4677 def = NULL; 4678 defobj = NULL; 4679 symlook_init_from_req(&req1, req); 4680 for (n = needed; n != NULL; n = n->next) { 4681 if (n->obj == NULL || 4682 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 4683 continue; 4684 if (def == NULL || (ld_dynamic_weak && 4685 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4686 def = req1.sym_out; 4687 defobj = req1.defobj_out; 4688 if (!ld_dynamic_weak || ELF_ST_BIND(def->st_info) != STB_WEAK) 4689 break; 4690 } 4691 } 4692 if (def != NULL) { 4693 req->sym_out = def; 4694 req->defobj_out = defobj; 4695 return (0); 4696 } 4697 return (ESRCH); 4698 } 4699 4700 /* 4701 * Search the symbol table of a single shared object for a symbol of 4702 * the given name and version, if requested. Returns a pointer to the 4703 * symbol, or NULL if no definition was found. If the object is 4704 * filter, return filtered symbol from filtee. 4705 * 4706 * The symbol's hash value is passed in for efficiency reasons; that 4707 * eliminates many recomputations of the hash value. 4708 */ 4709 int 4710 symlook_obj(SymLook *req, const Obj_Entry *obj) 4711 { 4712 DoneList donelist; 4713 SymLook req1; 4714 int flags, res, mres; 4715 4716 /* 4717 * If there is at least one valid hash at this point, we prefer to 4718 * use the faster GNU version if available. 4719 */ 4720 if (obj->valid_hash_gnu) 4721 mres = symlook_obj1_gnu(req, obj); 4722 else if (obj->valid_hash_sysv) 4723 mres = symlook_obj1_sysv(req, obj); 4724 else 4725 return (EINVAL); 4726 4727 if (mres == 0) { 4728 if (obj->needed_filtees != NULL) { 4729 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4730 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4731 donelist_init(&donelist); 4732 symlook_init_from_req(&req1, req); 4733 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 4734 if (res == 0) { 4735 req->sym_out = req1.sym_out; 4736 req->defobj_out = req1.defobj_out; 4737 } 4738 return (res); 4739 } 4740 if (obj->needed_aux_filtees != NULL) { 4741 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4742 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4743 donelist_init(&donelist); 4744 symlook_init_from_req(&req1, req); 4745 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 4746 if (res == 0) { 4747 req->sym_out = req1.sym_out; 4748 req->defobj_out = req1.defobj_out; 4749 return (res); 4750 } 4751 } 4752 } 4753 return (mres); 4754 } 4755 4756 /* Symbol match routine common to both hash functions */ 4757 static bool 4758 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4759 const unsigned long symnum) 4760 { 4761 Elf_Versym verndx; 4762 const Elf_Sym *symp; 4763 const char *strp; 4764 4765 symp = obj->symtab + symnum; 4766 strp = obj->strtab + symp->st_name; 4767 4768 switch (ELF_ST_TYPE(symp->st_info)) { 4769 case STT_FUNC: 4770 case STT_NOTYPE: 4771 case STT_OBJECT: 4772 case STT_COMMON: 4773 case STT_GNU_IFUNC: 4774 if (symp->st_value == 0) 4775 return (false); 4776 /* fallthrough */ 4777 case STT_TLS: 4778 if (symp->st_shndx != SHN_UNDEF) 4779 break; 4780 #ifndef __mips__ 4781 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4782 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4783 break; 4784 #endif 4785 /* fallthrough */ 4786 default: 4787 return (false); 4788 } 4789 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4790 return (false); 4791 4792 if (req->ventry == NULL) { 4793 if (obj->versyms != NULL) { 4794 verndx = VER_NDX(obj->versyms[symnum]); 4795 if (verndx > obj->vernum) { 4796 _rtld_error( 4797 "%s: symbol %s references wrong version %d", 4798 obj->path, obj->strtab + symnum, verndx); 4799 return (false); 4800 } 4801 /* 4802 * If we are not called from dlsym (i.e. this 4803 * is a normal relocation from unversioned 4804 * binary), accept the symbol immediately if 4805 * it happens to have first version after this 4806 * shared object became versioned. Otherwise, 4807 * if symbol is versioned and not hidden, 4808 * remember it. If it is the only symbol with 4809 * this name exported by the shared object, it 4810 * will be returned as a match by the calling 4811 * function. If symbol is global (verndx < 2) 4812 * accept it unconditionally. 4813 */ 4814 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4815 verndx == VER_NDX_GIVEN) { 4816 result->sym_out = symp; 4817 return (true); 4818 } 4819 else if (verndx >= VER_NDX_GIVEN) { 4820 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4821 == 0) { 4822 if (result->vsymp == NULL) 4823 result->vsymp = symp; 4824 result->vcount++; 4825 } 4826 return (false); 4827 } 4828 } 4829 result->sym_out = symp; 4830 return (true); 4831 } 4832 if (obj->versyms == NULL) { 4833 if (object_match_name(obj, req->ventry->name)) { 4834 _rtld_error("%s: object %s should provide version %s " 4835 "for symbol %s", obj_rtld.path, obj->path, 4836 req->ventry->name, obj->strtab + symnum); 4837 return (false); 4838 } 4839 } else { 4840 verndx = VER_NDX(obj->versyms[symnum]); 4841 if (verndx > obj->vernum) { 4842 _rtld_error("%s: symbol %s references wrong version %d", 4843 obj->path, obj->strtab + symnum, verndx); 4844 return (false); 4845 } 4846 if (obj->vertab[verndx].hash != req->ventry->hash || 4847 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4848 /* 4849 * Version does not match. Look if this is a 4850 * global symbol and if it is not hidden. If 4851 * global symbol (verndx < 2) is available, 4852 * use it. Do not return symbol if we are 4853 * called by dlvsym, because dlvsym looks for 4854 * a specific version and default one is not 4855 * what dlvsym wants. 4856 */ 4857 if ((req->flags & SYMLOOK_DLSYM) || 4858 (verndx >= VER_NDX_GIVEN) || 4859 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4860 return (false); 4861 } 4862 } 4863 result->sym_out = symp; 4864 return (true); 4865 } 4866 4867 /* 4868 * Search for symbol using SysV hash function. 4869 * obj->buckets is known not to be NULL at this point; the test for this was 4870 * performed with the obj->valid_hash_sysv assignment. 4871 */ 4872 static int 4873 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4874 { 4875 unsigned long symnum; 4876 Sym_Match_Result matchres; 4877 4878 matchres.sym_out = NULL; 4879 matchres.vsymp = NULL; 4880 matchres.vcount = 0; 4881 4882 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4883 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4884 if (symnum >= obj->nchains) 4885 return (ESRCH); /* Bad object */ 4886 4887 if (matched_symbol(req, obj, &matchres, symnum)) { 4888 req->sym_out = matchres.sym_out; 4889 req->defobj_out = obj; 4890 return (0); 4891 } 4892 } 4893 if (matchres.vcount == 1) { 4894 req->sym_out = matchres.vsymp; 4895 req->defobj_out = obj; 4896 return (0); 4897 } 4898 return (ESRCH); 4899 } 4900 4901 /* Search for symbol using GNU hash function */ 4902 static int 4903 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4904 { 4905 Elf_Addr bloom_word; 4906 const Elf32_Word *hashval; 4907 Elf32_Word bucket; 4908 Sym_Match_Result matchres; 4909 unsigned int h1, h2; 4910 unsigned long symnum; 4911 4912 matchres.sym_out = NULL; 4913 matchres.vsymp = NULL; 4914 matchres.vcount = 0; 4915 4916 /* Pick right bitmask word from Bloom filter array */ 4917 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4918 obj->maskwords_bm_gnu]; 4919 4920 /* Calculate modulus word size of gnu hash and its derivative */ 4921 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4922 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4923 4924 /* Filter out the "definitely not in set" queries */ 4925 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4926 return (ESRCH); 4927 4928 /* Locate hash chain and corresponding value element*/ 4929 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4930 if (bucket == 0) 4931 return (ESRCH); 4932 hashval = &obj->chain_zero_gnu[bucket]; 4933 do { 4934 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4935 symnum = hashval - obj->chain_zero_gnu; 4936 if (matched_symbol(req, obj, &matchres, symnum)) { 4937 req->sym_out = matchres.sym_out; 4938 req->defobj_out = obj; 4939 return (0); 4940 } 4941 } 4942 } while ((*hashval++ & 1) == 0); 4943 if (matchres.vcount == 1) { 4944 req->sym_out = matchres.vsymp; 4945 req->defobj_out = obj; 4946 return (0); 4947 } 4948 return (ESRCH); 4949 } 4950 4951 static void 4952 trace_loaded_objects(Obj_Entry *obj) 4953 { 4954 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4955 int c; 4956 4957 if ((main_local = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_PROGNAME)) == 4958 NULL) 4959 main_local = ""; 4960 4961 if ((fmt1 = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT1)) == NULL) 4962 fmt1 = "\t%o => %p (%x)\n"; 4963 4964 if ((fmt2 = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT2)) == NULL) 4965 fmt2 = "\t%o (%x)\n"; 4966 4967 list_containers = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_ALL); 4968 4969 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4970 Needed_Entry *needed; 4971 const char *name, *path; 4972 bool is_lib; 4973 4974 if (obj->marker) 4975 continue; 4976 if (list_containers && obj->needed != NULL) 4977 rtld_printf("%s:\n", obj->path); 4978 for (needed = obj->needed; needed; needed = needed->next) { 4979 if (needed->obj != NULL) { 4980 if (needed->obj->traced && !list_containers) 4981 continue; 4982 needed->obj->traced = true; 4983 path = needed->obj->path; 4984 } else 4985 path = "not found"; 4986 4987 name = obj->strtab + needed->name; 4988 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4989 4990 fmt = is_lib ? fmt1 : fmt2; 4991 while ((c = *fmt++) != '\0') { 4992 switch (c) { 4993 default: 4994 rtld_putchar(c); 4995 continue; 4996 case '\\': 4997 switch (c = *fmt) { 4998 case '\0': 4999 continue; 5000 case 'n': 5001 rtld_putchar('\n'); 5002 break; 5003 case 't': 5004 rtld_putchar('\t'); 5005 break; 5006 } 5007 break; 5008 case '%': 5009 switch (c = *fmt) { 5010 case '\0': 5011 continue; 5012 case '%': 5013 default: 5014 rtld_putchar(c); 5015 break; 5016 case 'A': 5017 rtld_putstr(main_local); 5018 break; 5019 case 'a': 5020 rtld_putstr(obj_main->path); 5021 break; 5022 case 'o': 5023 rtld_putstr(name); 5024 break; 5025 #if 0 5026 case 'm': 5027 rtld_printf("%d", sodp->sod_major); 5028 break; 5029 case 'n': 5030 rtld_printf("%d", sodp->sod_minor); 5031 break; 5032 #endif 5033 case 'p': 5034 rtld_putstr(path); 5035 break; 5036 case 'x': 5037 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 5038 0); 5039 break; 5040 } 5041 break; 5042 } 5043 ++fmt; 5044 } 5045 } 5046 } 5047 } 5048 5049 /* 5050 * Unload a dlopened object and its dependencies from memory and from 5051 * our data structures. It is assumed that the DAG rooted in the 5052 * object has already been unreferenced, and that the object has a 5053 * reference count of 0. 5054 */ 5055 static void 5056 unload_object(Obj_Entry *root, RtldLockState *lockstate) 5057 { 5058 Obj_Entry marker, *obj, *next; 5059 5060 assert(root->refcount == 0); 5061 5062 /* 5063 * Pass over the DAG removing unreferenced objects from 5064 * appropriate lists. 5065 */ 5066 unlink_object(root); 5067 5068 /* Unmap all objects that are no longer referenced. */ 5069 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) { 5070 next = TAILQ_NEXT(obj, next); 5071 if (obj->marker || obj->refcount != 0) 5072 continue; 5073 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 5074 obj->mapsize, 0, obj->path); 5075 dbg("unloading \"%s\"", obj->path); 5076 /* 5077 * Unlink the object now to prevent new references from 5078 * being acquired while the bind lock is dropped in 5079 * recursive dlclose() invocations. 5080 */ 5081 TAILQ_REMOVE(&obj_list, obj, next); 5082 obj_count--; 5083 5084 if (obj->filtees_loaded) { 5085 if (next != NULL) { 5086 init_marker(&marker); 5087 TAILQ_INSERT_BEFORE(next, &marker, next); 5088 unload_filtees(obj, lockstate); 5089 next = TAILQ_NEXT(&marker, next); 5090 TAILQ_REMOVE(&obj_list, &marker, next); 5091 } else 5092 unload_filtees(obj, lockstate); 5093 } 5094 release_object(obj); 5095 } 5096 } 5097 5098 static void 5099 unlink_object(Obj_Entry *root) 5100 { 5101 Objlist_Entry *elm; 5102 5103 if (root->refcount == 0) { 5104 /* Remove the object from the RTLD_GLOBAL list. */ 5105 objlist_remove(&list_global, root); 5106 5107 /* Remove the object from all objects' DAG lists. */ 5108 STAILQ_FOREACH(elm, &root->dagmembers, link) { 5109 objlist_remove(&elm->obj->dldags, root); 5110 if (elm->obj != root) 5111 unlink_object(elm->obj); 5112 } 5113 } 5114 } 5115 5116 static void 5117 ref_dag(Obj_Entry *root) 5118 { 5119 Objlist_Entry *elm; 5120 5121 assert(root->dag_inited); 5122 STAILQ_FOREACH(elm, &root->dagmembers, link) 5123 elm->obj->refcount++; 5124 } 5125 5126 static void 5127 unref_dag(Obj_Entry *root) 5128 { 5129 Objlist_Entry *elm; 5130 5131 assert(root->dag_inited); 5132 STAILQ_FOREACH(elm, &root->dagmembers, link) 5133 elm->obj->refcount--; 5134 } 5135 5136 /* 5137 * Common code for MD __tls_get_addr(). 5138 */ 5139 static void * 5140 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset, bool locked) 5141 { 5142 Elf_Addr *newdtv, *dtv; 5143 RtldLockState lockstate; 5144 int to_copy; 5145 5146 dtv = *dtvp; 5147 /* Check dtv generation in case new modules have arrived */ 5148 if (dtv[0] != tls_dtv_generation) { 5149 if (!locked) 5150 wlock_acquire(rtld_bind_lock, &lockstate); 5151 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5152 to_copy = dtv[1]; 5153 if (to_copy > tls_max_index) 5154 to_copy = tls_max_index; 5155 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 5156 newdtv[0] = tls_dtv_generation; 5157 newdtv[1] = tls_max_index; 5158 free(dtv); 5159 if (!locked) 5160 lock_release(rtld_bind_lock, &lockstate); 5161 dtv = *dtvp = newdtv; 5162 } 5163 5164 /* Dynamically allocate module TLS if necessary */ 5165 if (dtv[index + 1] == 0) { 5166 /* Signal safe, wlock will block out signals. */ 5167 if (!locked) 5168 wlock_acquire(rtld_bind_lock, &lockstate); 5169 if (!dtv[index + 1]) 5170 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 5171 if (!locked) 5172 lock_release(rtld_bind_lock, &lockstate); 5173 } 5174 return ((void *)(dtv[index + 1] + offset)); 5175 } 5176 5177 void * 5178 tls_get_addr_common(uintptr_t **dtvp, int index, size_t offset) 5179 { 5180 uintptr_t *dtv; 5181 5182 dtv = *dtvp; 5183 /* Check dtv generation in case new modules have arrived */ 5184 if (__predict_true(dtv[0] == tls_dtv_generation && 5185 dtv[index + 1] != 0)) 5186 return ((void *)(dtv[index + 1] + offset)); 5187 return (tls_get_addr_slow(dtvp, index, offset, false)); 5188 } 5189 5190 #ifdef TLS_VARIANT_I 5191 5192 /* 5193 * Return pointer to allocated TLS block 5194 */ 5195 static void * 5196 get_tls_block_ptr(void *tcb, size_t tcbsize) 5197 { 5198 size_t extra_size, post_size, pre_size, tls_block_size; 5199 size_t tls_init_align; 5200 5201 tls_init_align = MAX(obj_main->tlsalign, 1); 5202 5203 /* Compute fragments sizes. */ 5204 extra_size = tcbsize - TLS_TCB_SIZE; 5205 post_size = calculate_tls_post_size(tls_init_align); 5206 tls_block_size = tcbsize + post_size; 5207 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 5208 5209 return ((char *)tcb - pre_size - extra_size); 5210 } 5211 5212 /* 5213 * Allocate Static TLS using the Variant I method. 5214 * 5215 * For details on the layout, see lib/libc/gen/tls.c. 5216 * 5217 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as 5218 * it is based on tls_last_offset, and TLS offsets here are really TCB 5219 * offsets, whereas libc's tls_static_space is just the executable's static 5220 * TLS segment. 5221 */ 5222 void * 5223 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 5224 { 5225 Obj_Entry *obj; 5226 char *tls_block; 5227 Elf_Addr *dtv, **tcb; 5228 Elf_Addr addr; 5229 Elf_Addr i; 5230 size_t extra_size, maxalign, post_size, pre_size, tls_block_size; 5231 size_t tls_init_align, tls_init_offset; 5232 5233 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 5234 return (oldtcb); 5235 5236 assert(tcbsize >= TLS_TCB_SIZE); 5237 maxalign = MAX(tcbalign, tls_static_max_align); 5238 tls_init_align = MAX(obj_main->tlsalign, 1); 5239 5240 /* Compute fragmets sizes. */ 5241 extra_size = tcbsize - TLS_TCB_SIZE; 5242 post_size = calculate_tls_post_size(tls_init_align); 5243 tls_block_size = tcbsize + post_size; 5244 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 5245 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size; 5246 5247 /* Allocate whole TLS block */ 5248 tls_block = malloc_aligned(tls_block_size, maxalign, 0); 5249 tcb = (Elf_Addr **)(tls_block + pre_size + extra_size); 5250 5251 if (oldtcb != NULL) { 5252 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize), 5253 tls_static_space); 5254 free_aligned(get_tls_block_ptr(oldtcb, tcbsize)); 5255 5256 /* Adjust the DTV. */ 5257 dtv = tcb[0]; 5258 for (i = 0; i < dtv[1]; i++) { 5259 if (dtv[i+2] >= (Elf_Addr)oldtcb && 5260 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 5261 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tcb; 5262 } 5263 } 5264 } else { 5265 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5266 tcb[0] = dtv; 5267 dtv[0] = tls_dtv_generation; 5268 dtv[1] = tls_max_index; 5269 5270 for (obj = globallist_curr(objs); obj != NULL; 5271 obj = globallist_next(obj)) { 5272 if (obj->tlsoffset == 0) 5273 continue; 5274 tls_init_offset = obj->tlspoffset & (obj->tlsalign - 1); 5275 addr = (Elf_Addr)tcb + obj->tlsoffset; 5276 if (tls_init_offset > 0) 5277 memset((void *)addr, 0, tls_init_offset); 5278 if (obj->tlsinitsize > 0) { 5279 memcpy((void *)(addr + tls_init_offset), obj->tlsinit, 5280 obj->tlsinitsize); 5281 } 5282 if (obj->tlssize > obj->tlsinitsize) { 5283 memset((void *)(addr + tls_init_offset + obj->tlsinitsize), 5284 0, obj->tlssize - obj->tlsinitsize - tls_init_offset); 5285 } 5286 dtv[obj->tlsindex + 1] = addr; 5287 } 5288 } 5289 5290 return (tcb); 5291 } 5292 5293 void 5294 free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused) 5295 { 5296 Elf_Addr *dtv; 5297 Elf_Addr tlsstart, tlsend; 5298 size_t post_size; 5299 size_t dtvsize, i, tls_init_align; 5300 5301 assert(tcbsize >= TLS_TCB_SIZE); 5302 tls_init_align = MAX(obj_main->tlsalign, 1); 5303 5304 /* Compute fragments sizes. */ 5305 post_size = calculate_tls_post_size(tls_init_align); 5306 5307 tlsstart = (Elf_Addr)tcb + TLS_TCB_SIZE + post_size; 5308 tlsend = (Elf_Addr)tcb + tls_static_space; 5309 5310 dtv = *(Elf_Addr **)tcb; 5311 dtvsize = dtv[1]; 5312 for (i = 0; i < dtvsize; i++) { 5313 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 5314 free((void*)dtv[i+2]); 5315 } 5316 } 5317 free(dtv); 5318 free_aligned(get_tls_block_ptr(tcb, tcbsize)); 5319 } 5320 5321 #endif /* TLS_VARIANT_I */ 5322 5323 #ifdef TLS_VARIANT_II 5324 5325 /* 5326 * Allocate Static TLS using the Variant II method. 5327 */ 5328 void * 5329 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 5330 { 5331 Obj_Entry *obj; 5332 size_t size, ralign; 5333 char *tls; 5334 Elf_Addr *dtv, *olddtv; 5335 Elf_Addr segbase, oldsegbase, addr; 5336 size_t i; 5337 5338 ralign = tcbalign; 5339 if (tls_static_max_align > ralign) 5340 ralign = tls_static_max_align; 5341 size = roundup(tls_static_space, ralign) + roundup(tcbsize, ralign); 5342 5343 assert(tcbsize >= 2*sizeof(Elf_Addr)); 5344 tls = malloc_aligned(size, ralign, 0 /* XXX */); 5345 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5346 5347 segbase = (Elf_Addr)(tls + roundup(tls_static_space, ralign)); 5348 ((Elf_Addr *)segbase)[0] = segbase; 5349 ((Elf_Addr *)segbase)[1] = (Elf_Addr) dtv; 5350 5351 dtv[0] = tls_dtv_generation; 5352 dtv[1] = tls_max_index; 5353 5354 if (oldtls) { 5355 /* 5356 * Copy the static TLS block over whole. 5357 */ 5358 oldsegbase = (Elf_Addr) oldtls; 5359 memcpy((void *)(segbase - tls_static_space), 5360 (const void *)(oldsegbase - tls_static_space), 5361 tls_static_space); 5362 5363 /* 5364 * If any dynamic TLS blocks have been created tls_get_addr(), 5365 * move them over. 5366 */ 5367 olddtv = ((Elf_Addr **)oldsegbase)[1]; 5368 for (i = 0; i < olddtv[1]; i++) { 5369 if (olddtv[i + 2] < oldsegbase - size || 5370 olddtv[i + 2] > oldsegbase) { 5371 dtv[i + 2] = olddtv[i + 2]; 5372 olddtv[i + 2] = 0; 5373 } 5374 } 5375 5376 /* 5377 * We assume that this block was the one we created with 5378 * allocate_initial_tls(). 5379 */ 5380 free_tls(oldtls, 2 * sizeof(Elf_Addr), sizeof(Elf_Addr)); 5381 } else { 5382 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 5383 if (obj->marker || obj->tlsoffset == 0) 5384 continue; 5385 addr = segbase - obj->tlsoffset; 5386 memset((void *)(addr + obj->tlsinitsize), 5387 0, obj->tlssize - obj->tlsinitsize); 5388 if (obj->tlsinit) { 5389 memcpy((void *)addr, obj->tlsinit, obj->tlsinitsize); 5390 obj->static_tls_copied = true; 5391 } 5392 dtv[obj->tlsindex + 1] = addr; 5393 } 5394 } 5395 5396 return ((void *)segbase); 5397 } 5398 5399 void 5400 free_tls(void *tls, size_t tcbsize __unused, size_t tcbalign) 5401 { 5402 Elf_Addr* dtv; 5403 size_t size, ralign; 5404 int dtvsize, i; 5405 Elf_Addr tlsstart, tlsend; 5406 5407 /* 5408 * Figure out the size of the initial TLS block so that we can 5409 * find stuff which ___tls_get_addr() allocated dynamically. 5410 */ 5411 ralign = tcbalign; 5412 if (tls_static_max_align > ralign) 5413 ralign = tls_static_max_align; 5414 size = roundup(tls_static_space, ralign); 5415 5416 dtv = ((Elf_Addr **)tls)[1]; 5417 dtvsize = dtv[1]; 5418 tlsend = (Elf_Addr)tls; 5419 tlsstart = tlsend - size; 5420 for (i = 0; i < dtvsize; i++) { 5421 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || 5422 dtv[i + 2] > tlsend)) { 5423 free_aligned((void *)dtv[i + 2]); 5424 } 5425 } 5426 5427 free_aligned((void *)tlsstart); 5428 free((void *)dtv); 5429 } 5430 5431 #endif /* TLS_VARIANT_II */ 5432 5433 /* 5434 * Allocate TLS block for module with given index. 5435 */ 5436 void * 5437 allocate_module_tls(int index) 5438 { 5439 Obj_Entry *obj; 5440 char *p; 5441 5442 TAILQ_FOREACH(obj, &obj_list, next) { 5443 if (obj->marker) 5444 continue; 5445 if (obj->tlsindex == index) 5446 break; 5447 } 5448 if (obj == NULL) { 5449 _rtld_error("Can't find module with TLS index %d", index); 5450 rtld_die(); 5451 } 5452 5453 p = malloc_aligned(obj->tlssize, obj->tlsalign, obj->tlspoffset); 5454 memcpy(p, obj->tlsinit, obj->tlsinitsize); 5455 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 5456 return (p); 5457 } 5458 5459 bool 5460 allocate_tls_offset(Obj_Entry *obj) 5461 { 5462 size_t off; 5463 5464 if (obj->tls_done) 5465 return (true); 5466 5467 if (obj->tlssize == 0) { 5468 obj->tls_done = true; 5469 return (true); 5470 } 5471 5472 if (tls_last_offset == 0) 5473 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign, 5474 obj->tlspoffset); 5475 else 5476 off = calculate_tls_offset(tls_last_offset, tls_last_size, 5477 obj->tlssize, obj->tlsalign, obj->tlspoffset); 5478 5479 obj->tlsoffset = off; 5480 #ifdef TLS_VARIANT_I 5481 off += obj->tlssize; 5482 #endif 5483 5484 /* 5485 * If we have already fixed the size of the static TLS block, we 5486 * must stay within that size. When allocating the static TLS, we 5487 * leave a small amount of space spare to be used for dynamically 5488 * loading modules which use static TLS. 5489 */ 5490 if (tls_static_space != 0) { 5491 if (off > tls_static_space) 5492 return (false); 5493 } else if (obj->tlsalign > tls_static_max_align) { 5494 tls_static_max_align = obj->tlsalign; 5495 } 5496 5497 tls_last_offset = off; 5498 tls_last_size = obj->tlssize; 5499 obj->tls_done = true; 5500 5501 return (true); 5502 } 5503 5504 void 5505 free_tls_offset(Obj_Entry *obj) 5506 { 5507 5508 /* 5509 * If we were the last thing to allocate out of the static TLS 5510 * block, we give our space back to the 'allocator'. This is a 5511 * simplistic workaround to allow libGL.so.1 to be loaded and 5512 * unloaded multiple times. 5513 */ 5514 size_t off = obj->tlsoffset; 5515 #ifdef TLS_VARIANT_I 5516 off += obj->tlssize; 5517 #endif 5518 if (off == tls_last_offset) { 5519 tls_last_offset -= obj->tlssize; 5520 tls_last_size = 0; 5521 } 5522 } 5523 5524 void * 5525 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 5526 { 5527 void *ret; 5528 RtldLockState lockstate; 5529 5530 wlock_acquire(rtld_bind_lock, &lockstate); 5531 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 5532 tcbsize, tcbalign); 5533 lock_release(rtld_bind_lock, &lockstate); 5534 return (ret); 5535 } 5536 5537 void 5538 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 5539 { 5540 RtldLockState lockstate; 5541 5542 wlock_acquire(rtld_bind_lock, &lockstate); 5543 free_tls(tcb, tcbsize, tcbalign); 5544 lock_release(rtld_bind_lock, &lockstate); 5545 } 5546 5547 static void 5548 object_add_name(Obj_Entry *obj, const char *name) 5549 { 5550 Name_Entry *entry; 5551 size_t len; 5552 5553 len = strlen(name); 5554 entry = malloc(sizeof(Name_Entry) + len); 5555 5556 if (entry != NULL) { 5557 strcpy(entry->name, name); 5558 STAILQ_INSERT_TAIL(&obj->names, entry, link); 5559 } 5560 } 5561 5562 static int 5563 object_match_name(const Obj_Entry *obj, const char *name) 5564 { 5565 Name_Entry *entry; 5566 5567 STAILQ_FOREACH(entry, &obj->names, link) { 5568 if (strcmp(name, entry->name) == 0) 5569 return (1); 5570 } 5571 return (0); 5572 } 5573 5574 static Obj_Entry * 5575 locate_dependency(const Obj_Entry *obj, const char *name) 5576 { 5577 const Objlist_Entry *entry; 5578 const Needed_Entry *needed; 5579 5580 STAILQ_FOREACH(entry, &list_main, link) { 5581 if (object_match_name(entry->obj, name)) 5582 return (entry->obj); 5583 } 5584 5585 for (needed = obj->needed; needed != NULL; needed = needed->next) { 5586 if (strcmp(obj->strtab + needed->name, name) == 0 || 5587 (needed->obj != NULL && object_match_name(needed->obj, name))) { 5588 /* 5589 * If there is DT_NEEDED for the name we are looking for, 5590 * we are all set. Note that object might not be found if 5591 * dependency was not loaded yet, so the function can 5592 * return NULL here. This is expected and handled 5593 * properly by the caller. 5594 */ 5595 return (needed->obj); 5596 } 5597 } 5598 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 5599 obj->path, name); 5600 rtld_die(); 5601 } 5602 5603 static int 5604 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 5605 const Elf_Vernaux *vna) 5606 { 5607 const Elf_Verdef *vd; 5608 const char *vername; 5609 5610 vername = refobj->strtab + vna->vna_name; 5611 vd = depobj->verdef; 5612 if (vd == NULL) { 5613 _rtld_error("%s: version %s required by %s not defined", 5614 depobj->path, vername, refobj->path); 5615 return (-1); 5616 } 5617 for (;;) { 5618 if (vd->vd_version != VER_DEF_CURRENT) { 5619 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5620 depobj->path, vd->vd_version); 5621 return (-1); 5622 } 5623 if (vna->vna_hash == vd->vd_hash) { 5624 const Elf_Verdaux *aux = (const Elf_Verdaux *) 5625 ((const char *)vd + vd->vd_aux); 5626 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 5627 return (0); 5628 } 5629 if (vd->vd_next == 0) 5630 break; 5631 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5632 } 5633 if (vna->vna_flags & VER_FLG_WEAK) 5634 return (0); 5635 _rtld_error("%s: version %s required by %s not found", 5636 depobj->path, vername, refobj->path); 5637 return (-1); 5638 } 5639 5640 static int 5641 rtld_verify_object_versions(Obj_Entry *obj) 5642 { 5643 const Elf_Verneed *vn; 5644 const Elf_Verdef *vd; 5645 const Elf_Verdaux *vda; 5646 const Elf_Vernaux *vna; 5647 const Obj_Entry *depobj; 5648 int maxvernum, vernum; 5649 5650 if (obj->ver_checked) 5651 return (0); 5652 obj->ver_checked = true; 5653 5654 maxvernum = 0; 5655 /* 5656 * Walk over defined and required version records and figure out 5657 * max index used by any of them. Do very basic sanity checking 5658 * while there. 5659 */ 5660 vn = obj->verneed; 5661 while (vn != NULL) { 5662 if (vn->vn_version != VER_NEED_CURRENT) { 5663 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 5664 obj->path, vn->vn_version); 5665 return (-1); 5666 } 5667 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5668 for (;;) { 5669 vernum = VER_NEED_IDX(vna->vna_other); 5670 if (vernum > maxvernum) 5671 maxvernum = vernum; 5672 if (vna->vna_next == 0) 5673 break; 5674 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5675 } 5676 if (vn->vn_next == 0) 5677 break; 5678 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5679 } 5680 5681 vd = obj->verdef; 5682 while (vd != NULL) { 5683 if (vd->vd_version != VER_DEF_CURRENT) { 5684 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5685 obj->path, vd->vd_version); 5686 return (-1); 5687 } 5688 vernum = VER_DEF_IDX(vd->vd_ndx); 5689 if (vernum > maxvernum) 5690 maxvernum = vernum; 5691 if (vd->vd_next == 0) 5692 break; 5693 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5694 } 5695 5696 if (maxvernum == 0) 5697 return (0); 5698 5699 /* 5700 * Store version information in array indexable by version index. 5701 * Verify that object version requirements are satisfied along the 5702 * way. 5703 */ 5704 obj->vernum = maxvernum + 1; 5705 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 5706 5707 vd = obj->verdef; 5708 while (vd != NULL) { 5709 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 5710 vernum = VER_DEF_IDX(vd->vd_ndx); 5711 assert(vernum <= maxvernum); 5712 vda = (const Elf_Verdaux *)((const char *)vd + vd->vd_aux); 5713 obj->vertab[vernum].hash = vd->vd_hash; 5714 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 5715 obj->vertab[vernum].file = NULL; 5716 obj->vertab[vernum].flags = 0; 5717 } 5718 if (vd->vd_next == 0) 5719 break; 5720 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5721 } 5722 5723 vn = obj->verneed; 5724 while (vn != NULL) { 5725 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 5726 if (depobj == NULL) 5727 return (-1); 5728 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5729 for (;;) { 5730 if (check_object_provided_version(obj, depobj, vna)) 5731 return (-1); 5732 vernum = VER_NEED_IDX(vna->vna_other); 5733 assert(vernum <= maxvernum); 5734 obj->vertab[vernum].hash = vna->vna_hash; 5735 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 5736 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 5737 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 5738 VER_INFO_HIDDEN : 0; 5739 if (vna->vna_next == 0) 5740 break; 5741 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5742 } 5743 if (vn->vn_next == 0) 5744 break; 5745 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5746 } 5747 return (0); 5748 } 5749 5750 static int 5751 rtld_verify_versions(const Objlist *objlist) 5752 { 5753 Objlist_Entry *entry; 5754 int rc; 5755 5756 rc = 0; 5757 STAILQ_FOREACH(entry, objlist, link) { 5758 /* 5759 * Skip dummy objects or objects that have their version requirements 5760 * already checked. 5761 */ 5762 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 5763 continue; 5764 if (rtld_verify_object_versions(entry->obj) == -1) { 5765 rc = -1; 5766 if (ld_tracing == NULL) 5767 break; 5768 } 5769 } 5770 if (rc == 0 || ld_tracing != NULL) 5771 rc = rtld_verify_object_versions(&obj_rtld); 5772 return (rc); 5773 } 5774 5775 const Ver_Entry * 5776 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 5777 { 5778 Elf_Versym vernum; 5779 5780 if (obj->vertab) { 5781 vernum = VER_NDX(obj->versyms[symnum]); 5782 if (vernum >= obj->vernum) { 5783 _rtld_error("%s: symbol %s has wrong verneed value %d", 5784 obj->path, obj->strtab + symnum, vernum); 5785 } else if (obj->vertab[vernum].hash != 0) { 5786 return (&obj->vertab[vernum]); 5787 } 5788 } 5789 return (NULL); 5790 } 5791 5792 int 5793 _rtld_get_stack_prot(void) 5794 { 5795 5796 return (stack_prot); 5797 } 5798 5799 int 5800 _rtld_is_dlopened(void *arg) 5801 { 5802 Obj_Entry *obj; 5803 RtldLockState lockstate; 5804 int res; 5805 5806 rlock_acquire(rtld_bind_lock, &lockstate); 5807 obj = dlcheck(arg); 5808 if (obj == NULL) 5809 obj = obj_from_addr(arg); 5810 if (obj == NULL) { 5811 _rtld_error("No shared object contains address"); 5812 lock_release(rtld_bind_lock, &lockstate); 5813 return (-1); 5814 } 5815 res = obj->dlopened ? 1 : 0; 5816 lock_release(rtld_bind_lock, &lockstate); 5817 return (res); 5818 } 5819 5820 static int 5821 obj_remap_relro(Obj_Entry *obj, int prot) 5822 { 5823 5824 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size, 5825 prot) == -1) { 5826 _rtld_error("%s: Cannot set relro protection to %#x: %s", 5827 obj->path, prot, rtld_strerror(errno)); 5828 return (-1); 5829 } 5830 return (0); 5831 } 5832 5833 static int 5834 obj_disable_relro(Obj_Entry *obj) 5835 { 5836 5837 return (obj_remap_relro(obj, PROT_READ | PROT_WRITE)); 5838 } 5839 5840 static int 5841 obj_enforce_relro(Obj_Entry *obj) 5842 { 5843 5844 return (obj_remap_relro(obj, PROT_READ)); 5845 } 5846 5847 static void 5848 map_stacks_exec(RtldLockState *lockstate) 5849 { 5850 void (*thr_map_stacks_exec)(void); 5851 5852 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5853 return; 5854 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5855 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5856 if (thr_map_stacks_exec != NULL) { 5857 stack_prot |= PROT_EXEC; 5858 thr_map_stacks_exec(); 5859 } 5860 } 5861 5862 static void 5863 distribute_static_tls(Objlist *list, RtldLockState *lockstate) 5864 { 5865 Objlist_Entry *elm; 5866 Obj_Entry *obj; 5867 void (*distrib)(size_t, void *, size_t, size_t); 5868 5869 distrib = (void (*)(size_t, void *, size_t, size_t))(uintptr_t) 5870 get_program_var_addr("__pthread_distribute_static_tls", lockstate); 5871 if (distrib == NULL) 5872 return; 5873 STAILQ_FOREACH(elm, list, link) { 5874 obj = elm->obj; 5875 if (obj->marker || !obj->tls_done || obj->static_tls_copied) 5876 continue; 5877 distrib(obj->tlsoffset, obj->tlsinit, obj->tlsinitsize, 5878 obj->tlssize); 5879 obj->static_tls_copied = true; 5880 } 5881 } 5882 5883 void 5884 symlook_init(SymLook *dst, const char *name) 5885 { 5886 5887 bzero(dst, sizeof(*dst)); 5888 dst->name = name; 5889 dst->hash = elf_hash(name); 5890 dst->hash_gnu = gnu_hash(name); 5891 } 5892 5893 static void 5894 symlook_init_from_req(SymLook *dst, const SymLook *src) 5895 { 5896 5897 dst->name = src->name; 5898 dst->hash = src->hash; 5899 dst->hash_gnu = src->hash_gnu; 5900 dst->ventry = src->ventry; 5901 dst->flags = src->flags; 5902 dst->defobj_out = NULL; 5903 dst->sym_out = NULL; 5904 dst->lockstate = src->lockstate; 5905 } 5906 5907 static int 5908 open_binary_fd(const char *argv0, bool search_in_path, 5909 const char **binpath_res) 5910 { 5911 char *binpath, *pathenv, *pe, *res1; 5912 const char *res; 5913 int fd; 5914 5915 binpath = NULL; 5916 res = NULL; 5917 if (search_in_path && strchr(argv0, '/') == NULL) { 5918 binpath = xmalloc(PATH_MAX); 5919 pathenv = getenv("PATH"); 5920 if (pathenv == NULL) { 5921 _rtld_error("-p and no PATH environment variable"); 5922 rtld_die(); 5923 } 5924 pathenv = strdup(pathenv); 5925 if (pathenv == NULL) { 5926 _rtld_error("Cannot allocate memory"); 5927 rtld_die(); 5928 } 5929 fd = -1; 5930 errno = ENOENT; 5931 while ((pe = strsep(&pathenv, ":")) != NULL) { 5932 if (strlcpy(binpath, pe, PATH_MAX) >= PATH_MAX) 5933 continue; 5934 if (binpath[0] != '\0' && 5935 strlcat(binpath, "/", PATH_MAX) >= PATH_MAX) 5936 continue; 5937 if (strlcat(binpath, argv0, PATH_MAX) >= PATH_MAX) 5938 continue; 5939 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY); 5940 if (fd != -1 || errno != ENOENT) { 5941 res = binpath; 5942 break; 5943 } 5944 } 5945 free(pathenv); 5946 } else { 5947 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY); 5948 res = argv0; 5949 } 5950 5951 if (fd == -1) { 5952 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno)); 5953 rtld_die(); 5954 } 5955 if (res != NULL && res[0] != '/') { 5956 res1 = xmalloc(PATH_MAX); 5957 if (realpath(res, res1) != NULL) { 5958 if (res != argv0) 5959 free(__DECONST(char *, res)); 5960 res = res1; 5961 } else { 5962 free(res1); 5963 } 5964 } 5965 *binpath_res = res; 5966 return (fd); 5967 } 5968 5969 /* 5970 * Parse a set of command-line arguments. 5971 */ 5972 static int 5973 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp, 5974 const char **argv0, bool *dir_ignore) 5975 { 5976 const char *arg; 5977 char machine[64]; 5978 size_t sz; 5979 int arglen, fd, i, j, mib[2]; 5980 char opt; 5981 bool seen_b, seen_f; 5982 5983 dbg("Parsing command-line arguments"); 5984 *use_pathp = false; 5985 *fdp = -1; 5986 *dir_ignore = false; 5987 seen_b = seen_f = false; 5988 5989 for (i = 1; i < argc; i++ ) { 5990 arg = argv[i]; 5991 dbg("argv[%d]: '%s'", i, arg); 5992 5993 /* 5994 * rtld arguments end with an explicit "--" or with the first 5995 * non-prefixed argument. 5996 */ 5997 if (strcmp(arg, "--") == 0) { 5998 i++; 5999 break; 6000 } 6001 if (arg[0] != '-') 6002 break; 6003 6004 /* 6005 * All other arguments are single-character options that can 6006 * be combined, so we need to search through `arg` for them. 6007 */ 6008 arglen = strlen(arg); 6009 for (j = 1; j < arglen; j++) { 6010 opt = arg[j]; 6011 if (opt == 'h') { 6012 print_usage(argv[0]); 6013 _exit(0); 6014 } else if (opt == 'b') { 6015 if (seen_f) { 6016 _rtld_error("Both -b and -f specified"); 6017 rtld_die(); 6018 } 6019 i++; 6020 *argv0 = argv[i]; 6021 seen_b = true; 6022 break; 6023 } else if (opt == 'd') { 6024 *dir_ignore = true; 6025 break; 6026 } else if (opt == 'f') { 6027 if (seen_b) { 6028 _rtld_error("Both -b and -f specified"); 6029 rtld_die(); 6030 } 6031 6032 /* 6033 * -f XX can be used to specify a 6034 * descriptor for the binary named at 6035 * the command line (i.e., the later 6036 * argument will specify the process 6037 * name but the descriptor is what 6038 * will actually be executed). 6039 * 6040 * -f must be the last option in, e.g., -abcf. 6041 */ 6042 if (j != arglen - 1) { 6043 _rtld_error("Invalid options: %s", arg); 6044 rtld_die(); 6045 } 6046 i++; 6047 fd = parse_integer(argv[i]); 6048 if (fd == -1) { 6049 _rtld_error( 6050 "Invalid file descriptor: '%s'", 6051 argv[i]); 6052 rtld_die(); 6053 } 6054 *fdp = fd; 6055 seen_f = true; 6056 break; 6057 } else if (opt == 'p') { 6058 *use_pathp = true; 6059 } else if (opt == 'u') { 6060 trust = false; 6061 } else if (opt == 'v') { 6062 machine[0] = '\0'; 6063 mib[0] = CTL_HW; 6064 mib[1] = HW_MACHINE; 6065 sz = sizeof(machine); 6066 sysctl(mib, nitems(mib), machine, &sz, NULL, 0); 6067 ld_elf_hints_path = ld_get_env_var( 6068 LD_ELF_HINTS_PATH); 6069 set_ld_elf_hints_path(); 6070 rtld_printf( 6071 "FreeBSD ld-elf.so.1 %s\n" 6072 "FreeBSD_version %d\n" 6073 "Default lib path %s\n" 6074 "Hints lib path %s\n" 6075 "Env prefix %s\n" 6076 "Default hint file %s\n" 6077 "Hint file %s\n" 6078 "libmap file %s\n", 6079 machine, 6080 __FreeBSD_version, ld_standard_library_path, 6081 gethints(false), 6082 ld_env_prefix, ld_elf_hints_default, 6083 ld_elf_hints_path, 6084 ld_path_libmap_conf); 6085 _exit(0); 6086 } else { 6087 _rtld_error("Invalid argument: '%s'", arg); 6088 print_usage(argv[0]); 6089 rtld_die(); 6090 } 6091 } 6092 } 6093 6094 if (!seen_b) 6095 *argv0 = argv[i]; 6096 return (i); 6097 } 6098 6099 /* 6100 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 6101 */ 6102 static int 6103 parse_integer(const char *str) 6104 { 6105 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 6106 const char *orig; 6107 int n; 6108 char c; 6109 6110 orig = str; 6111 n = 0; 6112 for (c = *str; c != '\0'; c = *++str) { 6113 if (c < '0' || c > '9') 6114 return (-1); 6115 6116 n *= RADIX; 6117 n += c - '0'; 6118 } 6119 6120 /* Make sure we actually parsed something. */ 6121 if (str == orig) 6122 return (-1); 6123 return (n); 6124 } 6125 6126 static void 6127 print_usage(const char *argv0) 6128 { 6129 6130 rtld_printf( 6131 "Usage: %s [-h] [-b <exe>] [-d] [-f <FD>] [-p] [--] <binary> [<args>]\n" 6132 "\n" 6133 "Options:\n" 6134 " -h Display this help message\n" 6135 " -b <exe> Execute <exe> instead of <binary>, arg0 is <binary>\n" 6136 " -d Ignore lack of exec permissions for the binary\n" 6137 " -f <FD> Execute <FD> instead of searching for <binary>\n" 6138 " -p Search in PATH for named binary\n" 6139 " -u Ignore LD_ environment variables\n" 6140 " -v Display identification information\n" 6141 " -- End of RTLD options\n" 6142 " <binary> Name of process to execute\n" 6143 " <args> Arguments to the executed process\n", argv0); 6144 } 6145 6146 #define AUXFMT(at, xfmt) [at] = { .name = #at, .fmt = xfmt } 6147 static const struct auxfmt { 6148 const char *name; 6149 const char *fmt; 6150 } auxfmts[] = { 6151 AUXFMT(AT_NULL, NULL), 6152 AUXFMT(AT_IGNORE, NULL), 6153 AUXFMT(AT_EXECFD, "%ld"), 6154 AUXFMT(AT_PHDR, "%p"), 6155 AUXFMT(AT_PHENT, "%lu"), 6156 AUXFMT(AT_PHNUM, "%lu"), 6157 AUXFMT(AT_PAGESZ, "%lu"), 6158 AUXFMT(AT_BASE, "%#lx"), 6159 AUXFMT(AT_FLAGS, "%#lx"), 6160 AUXFMT(AT_ENTRY, "%p"), 6161 AUXFMT(AT_NOTELF, NULL), 6162 AUXFMT(AT_UID, "%ld"), 6163 AUXFMT(AT_EUID, "%ld"), 6164 AUXFMT(AT_GID, "%ld"), 6165 AUXFMT(AT_EGID, "%ld"), 6166 AUXFMT(AT_EXECPATH, "%s"), 6167 AUXFMT(AT_CANARY, "%p"), 6168 AUXFMT(AT_CANARYLEN, "%lu"), 6169 AUXFMT(AT_OSRELDATE, "%lu"), 6170 AUXFMT(AT_NCPUS, "%lu"), 6171 AUXFMT(AT_PAGESIZES, "%p"), 6172 AUXFMT(AT_PAGESIZESLEN, "%lu"), 6173 AUXFMT(AT_TIMEKEEP, "%p"), 6174 AUXFMT(AT_STACKPROT, "%#lx"), 6175 AUXFMT(AT_EHDRFLAGS, "%#lx"), 6176 AUXFMT(AT_HWCAP, "%#lx"), 6177 AUXFMT(AT_HWCAP2, "%#lx"), 6178 AUXFMT(AT_BSDFLAGS, "%#lx"), 6179 AUXFMT(AT_ARGC, "%lu"), 6180 AUXFMT(AT_ARGV, "%p"), 6181 AUXFMT(AT_ENVC, "%p"), 6182 AUXFMT(AT_ENVV, "%p"), 6183 AUXFMT(AT_PS_STRINGS, "%p"), 6184 AUXFMT(AT_FXRNG, "%p"), 6185 AUXFMT(AT_KPRELOAD, "%p"), 6186 }; 6187 6188 static bool 6189 is_ptr_fmt(const char *fmt) 6190 { 6191 char last; 6192 6193 last = fmt[strlen(fmt) - 1]; 6194 return (last == 'p' || last == 's'); 6195 } 6196 6197 static void 6198 dump_auxv(Elf_Auxinfo **aux_info) 6199 { 6200 Elf_Auxinfo *auxp; 6201 const struct auxfmt *fmt; 6202 int i; 6203 6204 for (i = 0; i < AT_COUNT; i++) { 6205 auxp = aux_info[i]; 6206 if (auxp == NULL) 6207 continue; 6208 fmt = &auxfmts[i]; 6209 if (fmt->fmt == NULL) 6210 continue; 6211 rtld_fdprintf(STDOUT_FILENO, "%s:\t", fmt->name); 6212 if (is_ptr_fmt(fmt->fmt)) { 6213 rtld_fdprintfx(STDOUT_FILENO, fmt->fmt, 6214 auxp->a_un.a_ptr); 6215 } else { 6216 rtld_fdprintfx(STDOUT_FILENO, fmt->fmt, 6217 auxp->a_un.a_val); 6218 } 6219 rtld_fdprintf(STDOUT_FILENO, "\n"); 6220 } 6221 } 6222 6223 /* 6224 * Overrides for libc_pic-provided functions. 6225 */ 6226 6227 int 6228 __getosreldate(void) 6229 { 6230 size_t len; 6231 int oid[2]; 6232 int error, osrel; 6233 6234 if (osreldate != 0) 6235 return (osreldate); 6236 6237 oid[0] = CTL_KERN; 6238 oid[1] = KERN_OSRELDATE; 6239 osrel = 0; 6240 len = sizeof(osrel); 6241 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 6242 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 6243 osreldate = osrel; 6244 return (osreldate); 6245 } 6246 const char * 6247 rtld_strerror(int errnum) 6248 { 6249 6250 if (errnum < 0 || errnum >= sys_nerr) 6251 return ("Unknown error"); 6252 return (sys_errlist[errnum]); 6253 } 6254 6255 char * 6256 getenv(const char *name) 6257 { 6258 return (__DECONST(char *, rtld_get_env_val(environ, name, 6259 strlen(name)))); 6260 } 6261 6262 /* malloc */ 6263 void * 6264 malloc(size_t nbytes) 6265 { 6266 6267 return (__crt_malloc(nbytes)); 6268 } 6269 6270 void * 6271 calloc(size_t num, size_t size) 6272 { 6273 6274 return (__crt_calloc(num, size)); 6275 } 6276 6277 void 6278 free(void *cp) 6279 { 6280 6281 __crt_free(cp); 6282 } 6283 6284 void * 6285 realloc(void *cp, size_t nbytes) 6286 { 6287 6288 return (__crt_realloc(cp, nbytes)); 6289 } 6290 6291 extern int _rtld_version__FreeBSD_version __exported; 6292 int _rtld_version__FreeBSD_version = __FreeBSD_version; 6293 6294 extern char _rtld_version_laddr_offset __exported; 6295 char _rtld_version_laddr_offset; 6296 6297 extern char _rtld_version_dlpi_tls_data __exported; 6298 char _rtld_version_dlpi_tls_data; 6299