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