1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 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/param.h> 42 #include <sys/mount.h> 43 #include <sys/mman.h> 44 #include <sys/stat.h> 45 #include <sys/sysctl.h> 46 #include <sys/uio.h> 47 #include <sys/utsname.h> 48 #include <sys/ktrace.h> 49 50 #include <dlfcn.h> 51 #include <err.h> 52 #include <errno.h> 53 #include <fcntl.h> 54 #include <stdarg.h> 55 #include <stdio.h> 56 #include <stdlib.h> 57 #include <string.h> 58 #include <unistd.h> 59 60 #include "debug.h" 61 #include "rtld.h" 62 #include "libmap.h" 63 #include "rtld_paths.h" 64 #include "rtld_tls.h" 65 #include "rtld_printf.h" 66 #include "rtld_malloc.h" 67 #include "rtld_utrace.h" 68 #include "notes.h" 69 #include "rtld_libc.h" 70 71 /* Types. */ 72 typedef void (*func_ptr_type)(void); 73 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 74 75 76 /* Variables that cannot be static: */ 77 extern struct r_debug r_debug; /* For GDB */ 78 extern int _thread_autoinit_dummy_decl; 79 extern void (*__cleanup)(void); 80 81 struct dlerror_save { 82 int seen; 83 char *msg; 84 }; 85 86 /* 87 * Function declarations. 88 */ 89 static const char *basename(const char *); 90 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 91 const Elf_Dyn **, const Elf_Dyn **); 92 static bool digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *, 93 const Elf_Dyn *); 94 static bool digest_dynamic(Obj_Entry *, int); 95 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 96 static void distribute_static_tls(Objlist *, RtldLockState *); 97 static Obj_Entry *dlcheck(void *); 98 static int dlclose_locked(void *, RtldLockState *); 99 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, 100 int lo_flags, int mode, RtldLockState *lockstate); 101 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 102 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 103 static bool donelist_check(DoneList *, const Obj_Entry *); 104 static void dump_auxv(Elf_Auxinfo **aux_info); 105 static void errmsg_restore(struct dlerror_save *); 106 static struct dlerror_save *errmsg_save(void); 107 static void *fill_search_info(const char *, size_t, void *); 108 static char *find_library(const char *, const Obj_Entry *, int *); 109 static const char *gethints(bool); 110 static void hold_object(Obj_Entry *); 111 static void unhold_object(Obj_Entry *); 112 static void init_dag(Obj_Entry *); 113 static void init_marker(Obj_Entry *); 114 static void init_pagesizes(Elf_Auxinfo **aux_info); 115 static void init_rtld(caddr_t, Elf_Auxinfo **); 116 static void initlist_add_neededs(Needed_Entry *, Objlist *); 117 static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *); 118 static int initlist_objects_ifunc(Objlist *, bool, int, RtldLockState *); 119 static void linkmap_add(Obj_Entry *); 120 static void linkmap_delete(Obj_Entry *); 121 static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 122 static void unload_filtees(Obj_Entry *, RtldLockState *); 123 static int load_needed_objects(Obj_Entry *, int); 124 static int load_preload_objects(const char *, bool); 125 static int load_kpreload(const void *addr); 126 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 127 static void map_stacks_exec(RtldLockState *); 128 static int obj_disable_relro(Obj_Entry *); 129 static int obj_enforce_relro(Obj_Entry *); 130 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 131 static void objlist_call_init(Objlist *, RtldLockState *); 132 static void objlist_clear(Objlist *); 133 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 134 static void objlist_init(Objlist *); 135 static void objlist_push_head(Objlist *, Obj_Entry *); 136 static void objlist_push_tail(Objlist *, Obj_Entry *); 137 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 138 static void objlist_remove(Objlist *, Obj_Entry *); 139 static int open_binary_fd(const char *argv0, bool search_in_path, 140 const char **binpath_res); 141 static int parse_args(char* argv[], int argc, bool *use_pathp, int *fdp, 142 const char **argv0, bool *dir_ignore); 143 static int parse_integer(const char *); 144 static void *path_enumerate(const char *, path_enum_proc, const char *, void *); 145 static void print_usage(const char *argv0); 146 static void release_object(Obj_Entry *); 147 static int relocate_object_dag(Obj_Entry *root, bool bind_now, 148 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 149 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 150 int flags, RtldLockState *lockstate); 151 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 152 RtldLockState *); 153 static int resolve_object_ifunc(Obj_Entry *, bool, int, RtldLockState *); 154 static int rtld_dirname(const char *, char *); 155 static int rtld_dirname_abs(const char *, char *); 156 static void *rtld_dlopen(const char *name, int fd, int mode); 157 static void rtld_exit(void); 158 static void rtld_nop_exit(void); 159 static char *search_library_path(const char *, const char *, const char *, 160 int *); 161 static char *search_library_pathfds(const char *, const char *, int *); 162 static const void **get_program_var_addr(const char *, RtldLockState *); 163 static void set_program_var(const char *, const void *); 164 static int symlook_default(SymLook *, const Obj_Entry *refobj); 165 static int symlook_global(SymLook *, DoneList *); 166 static void symlook_init_from_req(SymLook *, const SymLook *); 167 static int symlook_list(SymLook *, const Objlist *, DoneList *); 168 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 169 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 170 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 171 static void *tls_get_addr_slow(Elf_Addr **, int, size_t, bool) __noinline; 172 static void trace_loaded_objects(Obj_Entry *, bool); 173 static void unlink_object(Obj_Entry *); 174 static void unload_object(Obj_Entry *, RtldLockState *lockstate); 175 static void unref_dag(Obj_Entry *); 176 static void ref_dag(Obj_Entry *); 177 static char *origin_subst_one(Obj_Entry *, char *, const char *, 178 const char *, bool); 179 static char *origin_subst(Obj_Entry *, const char *); 180 static bool obj_resolve_origin(Obj_Entry *obj); 181 static void preinit_main(void); 182 static int rtld_verify_versions(const Objlist *); 183 static int rtld_verify_object_versions(Obj_Entry *); 184 static void object_add_name(Obj_Entry *, const char *); 185 static int object_match_name(const Obj_Entry *, const char *); 186 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 187 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 188 struct dl_phdr_info *phdr_info); 189 static uint32_t gnu_hash(const char *); 190 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 191 const unsigned long); 192 193 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported; 194 void _r_debug_postinit(struct link_map *) __noinline __exported; 195 196 int __sys_openat(int, const char *, int, ...); 197 198 /* 199 * Data declarations. 200 */ 201 struct r_debug r_debug __exported; /* for GDB; */ 202 static bool libmap_disable; /* Disable libmap */ 203 static bool ld_loadfltr; /* Immediate filters processing */ 204 static const char *libmap_override;/* Maps to use in addition to libmap.conf */ 205 static bool trust; /* False for setuid and setgid programs */ 206 static bool dangerous_ld_env; /* True if environment variables have been 207 used to affect the libraries loaded */ 208 bool ld_bind_not; /* Disable PLT update */ 209 static const char *ld_bind_now; /* Environment variable for immediate binding */ 210 static const char *ld_debug; /* Environment variable for debugging */ 211 static bool ld_dynamic_weak = true; /* True if non-weak definition overrides 212 weak definition */ 213 static const char *ld_library_path;/* Environment variable for search path */ 214 static const char *ld_library_dirs;/* Environment variable for library descriptors */ 215 static const char *ld_preload; /* Environment variable for libraries to 216 load first */ 217 static const char *ld_preload_fds;/* Environment variable for libraries represented by 218 descriptors */ 219 static const char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 220 static const char *ld_tracing; /* Called from ldd to print libs */ 221 static const char *ld_utrace; /* Use utrace() to log events. */ 222 static struct obj_entry_q obj_list; /* Queue of all loaded objects */ 223 static Obj_Entry *obj_main; /* The main program shared object */ 224 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 225 static unsigned int obj_count; /* Number of objects in obj_list */ 226 static unsigned int obj_loads; /* Number of loads of objects (gen count) */ 227 size_t ld_static_tls_extra = /* Static TLS extra space (bytes) */ 228 RTLD_STATIC_TLS_EXTRA; 229 230 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 231 STAILQ_HEAD_INITIALIZER(list_global); 232 static Objlist list_main = /* Objects loaded at program startup */ 233 STAILQ_HEAD_INITIALIZER(list_main); 234 static Objlist list_fini = /* Objects needing fini() calls */ 235 STAILQ_HEAD_INITIALIZER(list_fini); 236 237 Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 238 239 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 240 241 extern Elf_Dyn _DYNAMIC; 242 #pragma weak _DYNAMIC 243 244 int dlclose(void *) __exported; 245 char *dlerror(void) __exported; 246 void *dlopen(const char *, int) __exported; 247 void *fdlopen(int, int) __exported; 248 void *dlsym(void *, const char *) __exported; 249 dlfunc_t dlfunc(void *, const char *) __exported; 250 void *dlvsym(void *, const char *, const char *) __exported; 251 int dladdr(const void *, Dl_info *) __exported; 252 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *), 253 void (*)(void *), void (*)(void *), void (*)(void *)) __exported; 254 int dlinfo(void *, int , void *) __exported; 255 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported; 256 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported; 257 int _rtld_get_stack_prot(void) __exported; 258 int _rtld_is_dlopened(void *) __exported; 259 void _rtld_error(const char *, ...) __exported; 260 261 /* Only here to fix -Wmissing-prototypes warnings */ 262 int __getosreldate(void); 263 func_ptr_type _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp); 264 Elf_Addr _rtld_bind(Obj_Entry *obj, Elf_Size reloff); 265 266 int npagesizes; 267 static int osreldate; 268 size_t *pagesizes; 269 size_t page_size; 270 271 static int stack_prot = PROT_READ | PROT_WRITE | PROT_EXEC; 272 static int max_stack_flags; 273 274 /* 275 * Global declarations normally provided by crt1. The dynamic linker is 276 * not built with crt1, so we have to provide them ourselves. 277 */ 278 char *__progname; 279 char **environ; 280 281 /* 282 * Used to pass argc, argv to init functions. 283 */ 284 int main_argc; 285 char **main_argv; 286 287 /* 288 * Globals to control TLS allocation. 289 */ 290 size_t tls_last_offset; /* Static TLS offset of last module */ 291 size_t tls_last_size; /* Static TLS size of last module */ 292 size_t tls_static_space; /* Static TLS space allocated */ 293 static size_t tls_static_max_align; 294 Elf_Addr tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 295 int tls_max_index = 1; /* Largest module index allocated */ 296 297 static bool ld_library_path_rpath = false; 298 bool ld_fast_sigblock = false; 299 300 /* 301 * Globals for path names, and such 302 */ 303 const char *ld_elf_hints_default = _PATH_ELF_HINTS; 304 const char *ld_path_libmap_conf = _PATH_LIBMAP_CONF; 305 const char *ld_path_rtld = _PATH_RTLD; 306 const char *ld_standard_library_path = STANDARD_LIBRARY_PATH; 307 const char *ld_env_prefix = LD_; 308 309 static void (*rtld_exit_ptr)(void); 310 311 /* 312 * Fill in a DoneList with an allocation large enough to hold all of 313 * the currently-loaded objects. Keep this as a macro since it calls 314 * alloca and we want that to occur within the scope of the caller. 315 */ 316 #define donelist_init(dlp) \ 317 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 318 assert((dlp)->objs != NULL), \ 319 (dlp)->num_alloc = obj_count, \ 320 (dlp)->num_used = 0) 321 322 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 323 if (ld_utrace != NULL) \ 324 ld_utrace_log(e, h, mb, ms, r, n); \ 325 } while (0) 326 327 static void 328 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 329 int refcnt, const char *name) 330 { 331 struct utrace_rtld ut; 332 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG; 333 334 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig)); 335 ut.event = event; 336 ut.handle = handle; 337 ut.mapbase = mapbase; 338 ut.mapsize = mapsize; 339 ut.refcnt = refcnt; 340 bzero(ut.name, sizeof(ut.name)); 341 if (name) 342 strlcpy(ut.name, name, sizeof(ut.name)); 343 utrace(&ut, sizeof(ut)); 344 } 345 346 enum { 347 LD_BIND_NOW = 0, 348 LD_PRELOAD, 349 LD_LIBMAP, 350 LD_LIBRARY_PATH, 351 LD_LIBRARY_PATH_FDS, 352 LD_LIBMAP_DISABLE, 353 LD_BIND_NOT, 354 LD_DEBUG, 355 LD_ELF_HINTS_PATH, 356 LD_LOADFLTR, 357 LD_LIBRARY_PATH_RPATH, 358 LD_PRELOAD_FDS, 359 LD_DYNAMIC_WEAK, 360 LD_TRACE_LOADED_OBJECTS, 361 LD_UTRACE, 362 LD_DUMP_REL_PRE, 363 LD_DUMP_REL_POST, 364 LD_TRACE_LOADED_OBJECTS_PROGNAME, 365 LD_TRACE_LOADED_OBJECTS_FMT1, 366 LD_TRACE_LOADED_OBJECTS_FMT2, 367 LD_TRACE_LOADED_OBJECTS_ALL, 368 LD_SHOW_AUXV, 369 LD_STATIC_TLS_EXTRA, 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 LD_ENV_DESC(STATIC_TLS_EXTRA, false), 404 }; 405 406 static const char * 407 ld_get_env_var(int idx) 408 { 409 return (ld_env_vars[idx].val); 410 } 411 412 static const char * 413 rtld_get_env_val(char **env, const char *name, size_t name_len) 414 { 415 char **m, *n, *v; 416 417 for (m = env; *m != NULL; m++) { 418 n = *m; 419 v = strchr(n, '='); 420 if (v == NULL) { 421 /* corrupt environment? */ 422 continue; 423 } 424 if (v - n == (ptrdiff_t)name_len && 425 strncmp(name, n, name_len) == 0) 426 return (v + 1); 427 } 428 return (NULL); 429 } 430 431 static void 432 rtld_init_env_vars_for_prefix(char **env, const char *env_prefix) 433 { 434 struct ld_env_var_desc *lvd; 435 size_t prefix_len, nlen; 436 char **m, *n, *v; 437 int i; 438 439 prefix_len = strlen(env_prefix); 440 for (m = env; *m != NULL; m++) { 441 n = *m; 442 if (strncmp(env_prefix, n, prefix_len) != 0) { 443 /* Not a rtld environment variable. */ 444 continue; 445 } 446 n += prefix_len; 447 v = strchr(n, '='); 448 if (v == NULL) { 449 /* corrupt environment? */ 450 continue; 451 } 452 for (i = 0; i < (int)nitems(ld_env_vars); i++) { 453 lvd = &ld_env_vars[i]; 454 if (lvd->val != NULL) { 455 /* Saw higher-priority variable name already. */ 456 continue; 457 } 458 nlen = strlen(lvd->n); 459 if (v - n == (ptrdiff_t)nlen && 460 strncmp(lvd->n, n, nlen) == 0) { 461 lvd->val = v + 1; 462 break; 463 } 464 } 465 } 466 } 467 468 static void 469 rtld_init_env_vars(char **env) 470 { 471 rtld_init_env_vars_for_prefix(env, ld_env_prefix); 472 } 473 474 static void 475 set_ld_elf_hints_path(void) 476 { 477 if (ld_elf_hints_path == NULL || strlen(ld_elf_hints_path) == 0) 478 ld_elf_hints_path = ld_elf_hints_default; 479 } 480 481 uintptr_t 482 rtld_round_page(uintptr_t x) 483 { 484 return (roundup2(x, page_size)); 485 } 486 487 uintptr_t 488 rtld_trunc_page(uintptr_t x) 489 { 490 return (rounddown2(x, page_size)); 491 } 492 493 /* 494 * Main entry point for dynamic linking. The first argument is the 495 * stack pointer. The stack is expected to be laid out as described 496 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 497 * Specifically, the stack pointer points to a word containing 498 * ARGC. Following that in the stack is a null-terminated sequence 499 * of pointers to argument strings. Then comes a null-terminated 500 * sequence of pointers to environment strings. Finally, there is a 501 * sequence of "auxiliary vector" entries. 502 * 503 * The second argument points to a place to store the dynamic linker's 504 * exit procedure pointer and the third to a place to store the main 505 * program's object. 506 * 507 * The return value is the main program's entry point. 508 */ 509 func_ptr_type 510 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 511 { 512 Elf_Auxinfo *aux, *auxp, *auxpf, *aux_info[AT_COUNT]; 513 Objlist_Entry *entry; 514 Obj_Entry *last_interposer, *obj, *preload_tail; 515 const Elf_Phdr *phdr; 516 Objlist initlist; 517 RtldLockState lockstate; 518 struct stat st; 519 Elf_Addr *argcp; 520 char **argv, **env, **envp, *kexecpath; 521 const char *argv0, *binpath, *library_path_rpath, *static_tls_extra; 522 struct ld_env_var_desc *lvd; 523 caddr_t imgentry; 524 char buf[MAXPATHLEN]; 525 int argc, fd, i, mib[4], old_osrel, osrel, phnum, rtld_argc; 526 size_t sz; 527 #ifdef __powerpc__ 528 int old_auxv_format = 1; 529 #endif 530 bool dir_enable, dir_ignore, direct_exec, explicit_fd, search_in_path; 531 532 /* 533 * On entry, the dynamic linker itself has not been relocated yet. 534 * Be very careful not to reference any global data until after 535 * init_rtld has returned. It is OK to reference file-scope statics 536 * and string constants, and to call static and global functions. 537 */ 538 539 /* Find the auxiliary vector on the stack. */ 540 argcp = sp; 541 argc = *sp++; 542 argv = (char **) sp; 543 sp += argc + 1; /* Skip over arguments and NULL terminator */ 544 env = (char **) sp; 545 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 546 ; 547 aux = (Elf_Auxinfo *) sp; 548 549 /* Digest the auxiliary vector. */ 550 for (i = 0; i < AT_COUNT; i++) 551 aux_info[i] = NULL; 552 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 553 if (auxp->a_type < AT_COUNT) 554 aux_info[auxp->a_type] = auxp; 555 #ifdef __powerpc__ 556 if (auxp->a_type == 23) /* AT_STACKPROT */ 557 old_auxv_format = 0; 558 #endif 559 } 560 561 #ifdef __powerpc__ 562 if (old_auxv_format) { 563 /* Remap from old-style auxv numbers. */ 564 aux_info[23] = aux_info[21]; /* AT_STACKPROT */ 565 aux_info[21] = aux_info[19]; /* AT_PAGESIZESLEN */ 566 aux_info[19] = aux_info[17]; /* AT_NCPUS */ 567 aux_info[17] = aux_info[15]; /* AT_CANARYLEN */ 568 aux_info[15] = aux_info[13]; /* AT_EXECPATH */ 569 aux_info[13] = NULL; /* AT_GID */ 570 571 aux_info[20] = aux_info[18]; /* AT_PAGESIZES */ 572 aux_info[18] = aux_info[16]; /* AT_OSRELDATE */ 573 aux_info[16] = aux_info[14]; /* AT_CANARY */ 574 aux_info[14] = NULL; /* AT_EGID */ 575 } 576 #endif 577 578 /* Initialize and relocate ourselves. */ 579 assert(aux_info[AT_BASE] != NULL); 580 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 581 582 dlerror_dflt_init(); 583 584 __progname = obj_rtld.path; 585 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 586 environ = env; 587 main_argc = argc; 588 main_argv = argv; 589 590 if (aux_info[AT_BSDFLAGS] != NULL && 591 (aux_info[AT_BSDFLAGS]->a_un.a_val & ELF_BSDF_SIGFASTBLK) != 0) 592 ld_fast_sigblock = true; 593 594 trust = !issetugid(); 595 direct_exec = false; 596 597 md_abi_variant_hook(aux_info); 598 rtld_init_env_vars(env); 599 600 fd = -1; 601 if (aux_info[AT_EXECFD] != NULL) { 602 fd = aux_info[AT_EXECFD]->a_un.a_val; 603 } else { 604 assert(aux_info[AT_PHDR] != NULL); 605 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr; 606 if (phdr == obj_rtld.phdr) { 607 if (!trust) { 608 _rtld_error("Tainted process refusing to run binary %s", 609 argv0); 610 rtld_die(); 611 } 612 direct_exec = true; 613 614 dbg("opening main program in direct exec mode"); 615 if (argc >= 2) { 616 rtld_argc = parse_args(argv, argc, &search_in_path, &fd, 617 &argv0, &dir_ignore); 618 explicit_fd = (fd != -1); 619 binpath = NULL; 620 if (!explicit_fd) 621 fd = open_binary_fd(argv0, search_in_path, &binpath); 622 if (fstat(fd, &st) == -1) { 623 _rtld_error("Failed to fstat FD %d (%s): %s", fd, 624 explicit_fd ? "user-provided descriptor" : argv0, 625 rtld_strerror(errno)); 626 rtld_die(); 627 } 628 629 /* 630 * Rough emulation of the permission checks done by 631 * execve(2), only Unix DACs are checked, ACLs are 632 * ignored. Preserve the semantic of disabling owner 633 * to execute if owner x bit is cleared, even if 634 * others x bit is enabled. 635 * mmap(2) does not allow to mmap with PROT_EXEC if 636 * binary' file comes from noexec mount. We cannot 637 * set a text reference on the binary. 638 */ 639 dir_enable = false; 640 if (st.st_uid == geteuid()) { 641 if ((st.st_mode & S_IXUSR) != 0) 642 dir_enable = true; 643 } else if (st.st_gid == getegid()) { 644 if ((st.st_mode & S_IXGRP) != 0) 645 dir_enable = true; 646 } else if ((st.st_mode & S_IXOTH) != 0) { 647 dir_enable = true; 648 } 649 if (!dir_enable && !dir_ignore) { 650 _rtld_error("No execute permission for binary %s", 651 argv0); 652 rtld_die(); 653 } 654 655 /* 656 * For direct exec mode, argv[0] is the interpreter 657 * name, we must remove it and shift arguments left 658 * before invoking binary main. Since stack layout 659 * places environment pointers and aux vectors right 660 * after the terminating NULL, we must shift 661 * environment and aux as well. 662 */ 663 main_argc = argc - rtld_argc; 664 for (i = 0; i <= main_argc; i++) 665 argv[i] = argv[i + rtld_argc]; 666 *argcp -= rtld_argc; 667 environ = env = envp = argv + main_argc + 1; 668 dbg("move env from %p to %p", envp + rtld_argc, envp); 669 do { 670 *envp = *(envp + rtld_argc); 671 } while (*envp++ != NULL); 672 aux = auxp = (Elf_Auxinfo *)envp; 673 auxpf = (Elf_Auxinfo *)(envp + rtld_argc); 674 dbg("move aux from %p to %p", auxpf, aux); 675 /* XXXKIB insert place for AT_EXECPATH if not present */ 676 for (;; auxp++, auxpf++) { 677 *auxp = *auxpf; 678 if (auxp->a_type == AT_NULL) 679 break; 680 } 681 /* Since the auxiliary vector has moved, redigest it. */ 682 for (i = 0; i < AT_COUNT; i++) 683 aux_info[i] = NULL; 684 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 685 if (auxp->a_type < AT_COUNT) 686 aux_info[auxp->a_type] = auxp; 687 } 688 689 /* Point AT_EXECPATH auxv and aux_info to the binary path. */ 690 if (binpath == NULL) { 691 aux_info[AT_EXECPATH] = NULL; 692 } else { 693 if (aux_info[AT_EXECPATH] == NULL) { 694 aux_info[AT_EXECPATH] = xmalloc(sizeof(Elf_Auxinfo)); 695 aux_info[AT_EXECPATH]->a_type = AT_EXECPATH; 696 } 697 aux_info[AT_EXECPATH]->a_un.a_ptr = __DECONST(void *, 698 binpath); 699 } 700 } else { 701 _rtld_error("No binary"); 702 rtld_die(); 703 } 704 } 705 } 706 707 ld_bind_now = ld_get_env_var(LD_BIND_NOW); 708 709 /* 710 * If the process is tainted, then we un-set the dangerous environment 711 * variables. The process will be marked as tainted until setuid(2) 712 * is called. If any child process calls setuid(2) we do not want any 713 * future processes to honor the potentially un-safe variables. 714 */ 715 if (!trust) { 716 for (i = 0; i < (int)nitems(ld_env_vars); i++) { 717 lvd = &ld_env_vars[i]; 718 if (lvd->unsecure) 719 lvd->val = NULL; 720 } 721 } 722 723 ld_debug = ld_get_env_var(LD_DEBUG); 724 if (ld_bind_now == NULL) 725 ld_bind_not = ld_get_env_var(LD_BIND_NOT) != NULL; 726 ld_dynamic_weak = ld_get_env_var(LD_DYNAMIC_WEAK) == NULL; 727 libmap_disable = ld_get_env_var(LD_LIBMAP_DISABLE) != NULL; 728 libmap_override = ld_get_env_var(LD_LIBMAP); 729 ld_library_path = ld_get_env_var(LD_LIBRARY_PATH); 730 ld_library_dirs = ld_get_env_var(LD_LIBRARY_PATH_FDS); 731 ld_preload = ld_get_env_var(LD_PRELOAD); 732 ld_preload_fds = ld_get_env_var(LD_PRELOAD_FDS); 733 ld_elf_hints_path = ld_get_env_var(LD_ELF_HINTS_PATH); 734 ld_loadfltr = ld_get_env_var(LD_LOADFLTR) != NULL; 735 library_path_rpath = ld_get_env_var(LD_LIBRARY_PATH_RPATH); 736 if (library_path_rpath != NULL) { 737 if (library_path_rpath[0] == 'y' || 738 library_path_rpath[0] == 'Y' || 739 library_path_rpath[0] == '1') 740 ld_library_path_rpath = true; 741 else 742 ld_library_path_rpath = false; 743 } 744 static_tls_extra = ld_get_env_var(LD_STATIC_TLS_EXTRA); 745 if (static_tls_extra != NULL && static_tls_extra[0] != '\0') { 746 sz = parse_integer(static_tls_extra); 747 if (sz >= RTLD_STATIC_TLS_EXTRA && sz <= SIZE_T_MAX) 748 ld_static_tls_extra = sz; 749 } 750 dangerous_ld_env = libmap_disable || libmap_override != NULL || 751 ld_library_path != NULL || ld_preload != NULL || 752 ld_elf_hints_path != NULL || ld_loadfltr || !ld_dynamic_weak || 753 static_tls_extra != NULL; 754 ld_tracing = ld_get_env_var(LD_TRACE_LOADED_OBJECTS); 755 ld_utrace = ld_get_env_var(LD_UTRACE); 756 757 set_ld_elf_hints_path(); 758 if (ld_debug != NULL && *ld_debug != '\0') 759 debug = 1; 760 dbg("%s is initialized, base address = %p", __progname, 761 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 762 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 763 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 764 765 dbg("initializing thread locks"); 766 lockdflt_init(); 767 768 /* 769 * Load the main program, or process its program header if it is 770 * already loaded. 771 */ 772 if (fd != -1) { /* Load the main program. */ 773 dbg("loading main program"); 774 obj_main = map_object(fd, argv0, NULL); 775 close(fd); 776 if (obj_main == NULL) 777 rtld_die(); 778 max_stack_flags = obj_main->stack_flags; 779 } else { /* Main program already loaded. */ 780 dbg("processing main program's program header"); 781 assert(aux_info[AT_PHDR] != NULL); 782 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 783 assert(aux_info[AT_PHNUM] != NULL); 784 phnum = aux_info[AT_PHNUM]->a_un.a_val; 785 assert(aux_info[AT_PHENT] != NULL); 786 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 787 assert(aux_info[AT_ENTRY] != NULL); 788 imgentry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 789 if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) == NULL) 790 rtld_die(); 791 } 792 793 if (aux_info[AT_EXECPATH] != NULL && fd == -1) { 794 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 795 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 796 if (kexecpath[0] == '/') 797 obj_main->path = kexecpath; 798 else if (getcwd(buf, sizeof(buf)) == NULL || 799 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 800 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 801 obj_main->path = xstrdup(argv0); 802 else 803 obj_main->path = xstrdup(buf); 804 } else { 805 dbg("No AT_EXECPATH or direct exec"); 806 obj_main->path = xstrdup(argv0); 807 } 808 dbg("obj_main path %s", obj_main->path); 809 obj_main->mainprog = true; 810 811 if (aux_info[AT_STACKPROT] != NULL && 812 aux_info[AT_STACKPROT]->a_un.a_val != 0) 813 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 814 815 #ifndef COMPAT_libcompat 816 /* 817 * Get the actual dynamic linker pathname from the executable if 818 * possible. (It should always be possible.) That ensures that 819 * gdb will find the right dynamic linker even if a non-standard 820 * one is being used. 821 */ 822 if (obj_main->interp != NULL && 823 strcmp(obj_main->interp, obj_rtld.path) != 0) { 824 free(obj_rtld.path); 825 obj_rtld.path = xstrdup(obj_main->interp); 826 __progname = obj_rtld.path; 827 } 828 #endif 829 830 if (!digest_dynamic(obj_main, 0)) 831 rtld_die(); 832 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 833 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 834 obj_main->dynsymcount); 835 836 linkmap_add(obj_main); 837 linkmap_add(&obj_rtld); 838 839 /* Link the main program into the list of objects. */ 840 TAILQ_INSERT_HEAD(&obj_list, obj_main, next); 841 obj_count++; 842 obj_loads++; 843 844 /* Initialize a fake symbol for resolving undefined weak references. */ 845 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 846 sym_zero.st_shndx = SHN_UNDEF; 847 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 848 849 if (!libmap_disable) 850 libmap_disable = (bool)lm_init(libmap_override); 851 852 if (aux_info[AT_KPRELOAD] != NULL && 853 aux_info[AT_KPRELOAD]->a_un.a_ptr != NULL) { 854 dbg("loading kernel vdso"); 855 if (load_kpreload(aux_info[AT_KPRELOAD]->a_un.a_ptr) == -1) 856 rtld_die(); 857 } 858 859 dbg("loading LD_PRELOAD_FDS libraries"); 860 if (load_preload_objects(ld_preload_fds, true) == -1) 861 rtld_die(); 862 863 dbg("loading LD_PRELOAD libraries"); 864 if (load_preload_objects(ld_preload, false) == -1) 865 rtld_die(); 866 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 867 868 dbg("loading needed objects"); 869 if (load_needed_objects(obj_main, ld_tracing != NULL ? RTLD_LO_TRACE : 870 0) == -1) 871 rtld_die(); 872 873 /* Make a list of all objects loaded at startup. */ 874 last_interposer = obj_main; 875 TAILQ_FOREACH(obj, &obj_list, next) { 876 if (obj->marker) 877 continue; 878 if (obj->z_interpose && obj != obj_main) { 879 objlist_put_after(&list_main, last_interposer, obj); 880 last_interposer = obj; 881 } else { 882 objlist_push_tail(&list_main, obj); 883 } 884 obj->refcount++; 885 } 886 887 dbg("checking for required versions"); 888 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 889 rtld_die(); 890 891 if (ld_get_env_var(LD_SHOW_AUXV) != NULL) 892 dump_auxv(aux_info); 893 894 if (ld_tracing) { /* We're done */ 895 trace_loaded_objects(obj_main, true); 896 exit(0); 897 } 898 899 if (ld_get_env_var(LD_DUMP_REL_PRE) != NULL) { 900 dump_relocations(obj_main); 901 exit (0); 902 } 903 904 /* 905 * Processing tls relocations requires having the tls offsets 906 * initialized. Prepare offsets before starting initial 907 * relocation processing. 908 */ 909 dbg("initializing initial thread local storage offsets"); 910 STAILQ_FOREACH(entry, &list_main, link) { 911 /* 912 * Allocate all the initial objects out of the static TLS 913 * block even if they didn't ask for it. 914 */ 915 allocate_tls_offset(entry->obj); 916 } 917 918 if (relocate_objects(obj_main, 919 ld_bind_now != NULL && *ld_bind_now != '\0', 920 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 921 rtld_die(); 922 923 dbg("doing copy relocations"); 924 if (do_copy_relocations(obj_main) == -1) 925 rtld_die(); 926 927 if (ld_get_env_var(LD_DUMP_REL_POST) != NULL) { 928 dump_relocations(obj_main); 929 exit (0); 930 } 931 932 ifunc_init(aux); 933 934 /* 935 * Setup TLS for main thread. This must be done after the 936 * relocations are processed, since tls initialization section 937 * might be the subject for relocations. 938 */ 939 dbg("initializing initial thread local storage"); 940 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list))); 941 942 dbg("initializing key program variables"); 943 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 944 set_program_var("environ", env); 945 set_program_var("__elf_aux_vector", aux); 946 947 /* Make a list of init functions to call. */ 948 objlist_init(&initlist); 949 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)), 950 preload_tail, &initlist); 951 952 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 953 954 map_stacks_exec(NULL); 955 956 if (!obj_main->crt_no_init) { 957 /* 958 * Make sure we don't call the main program's init and fini 959 * functions for binaries linked with old crt1 which calls 960 * _init itself. 961 */ 962 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 963 obj_main->preinit_array = obj_main->init_array = 964 obj_main->fini_array = (Elf_Addr)NULL; 965 } 966 967 if (direct_exec) { 968 /* Set osrel for direct-execed binary */ 969 mib[0] = CTL_KERN; 970 mib[1] = KERN_PROC; 971 mib[2] = KERN_PROC_OSREL; 972 mib[3] = getpid(); 973 osrel = obj_main->osrel; 974 sz = sizeof(old_osrel); 975 dbg("setting osrel to %d", osrel); 976 (void)sysctl(mib, 4, &old_osrel, &sz, &osrel, sizeof(osrel)); 977 } 978 979 wlock_acquire(rtld_bind_lock, &lockstate); 980 981 dbg("resolving ifuncs"); 982 if (initlist_objects_ifunc(&initlist, ld_bind_now != NULL && 983 *ld_bind_now != '\0', SYMLOOK_EARLY, &lockstate) == -1) 984 rtld_die(); 985 986 rtld_exit_ptr = rtld_exit; 987 if (obj_main->crt_no_init) 988 preinit_main(); 989 objlist_call_init(&initlist, &lockstate); 990 _r_debug_postinit(&obj_main->linkmap); 991 objlist_clear(&initlist); 992 dbg("loading filtees"); 993 TAILQ_FOREACH(obj, &obj_list, next) { 994 if (obj->marker) 995 continue; 996 if (ld_loadfltr || obj->z_loadfltr) 997 load_filtees(obj, 0, &lockstate); 998 } 999 1000 dbg("enforcing main obj relro"); 1001 if (obj_enforce_relro(obj_main) == -1) 1002 rtld_die(); 1003 1004 lock_release(rtld_bind_lock, &lockstate); 1005 1006 dbg("transferring control to program entry point = %p", obj_main->entry); 1007 1008 /* Return the exit procedure and the program entry point. */ 1009 *exit_proc = rtld_exit_ptr; 1010 *objp = obj_main; 1011 return ((func_ptr_type)obj_main->entry); 1012 } 1013 1014 void * 1015 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 1016 { 1017 void *ptr; 1018 Elf_Addr target; 1019 1020 ptr = (void *)make_function_pointer(def, obj); 1021 target = call_ifunc_resolver(ptr); 1022 return ((void *)target); 1023 } 1024 1025 Elf_Addr 1026 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 1027 { 1028 const Elf_Rel *rel; 1029 const Elf_Sym *def; 1030 const Obj_Entry *defobj; 1031 Elf_Addr *where; 1032 Elf_Addr target; 1033 RtldLockState lockstate; 1034 1035 rlock_acquire(rtld_bind_lock, &lockstate); 1036 if (sigsetjmp(lockstate.env, 0) != 0) 1037 lock_upgrade(rtld_bind_lock, &lockstate); 1038 if (obj->pltrel) 1039 rel = (const Elf_Rel *)((const char *)obj->pltrel + reloff); 1040 else 1041 rel = (const Elf_Rel *)((const char *)obj->pltrela + reloff); 1042 1043 where = (Elf_Addr *)(obj->relocbase + rel->r_offset); 1044 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT, 1045 NULL, &lockstate); 1046 if (def == NULL) 1047 rtld_die(); 1048 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 1049 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 1050 else 1051 target = (Elf_Addr)(defobj->relocbase + def->st_value); 1052 1053 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 1054 defobj->strtab + def->st_name, 1055 obj->path == NULL ? NULL : basename(obj->path), 1056 (void *)target, 1057 defobj->path == NULL ? NULL : basename(defobj->path)); 1058 1059 /* 1060 * Write the new contents for the jmpslot. Note that depending on 1061 * architecture, the value which we need to return back to the 1062 * lazy binding trampoline may or may not be the target 1063 * address. The value returned from reloc_jmpslot() is the value 1064 * that the trampoline needs. 1065 */ 1066 target = reloc_jmpslot(where, target, defobj, obj, rel); 1067 lock_release(rtld_bind_lock, &lockstate); 1068 return (target); 1069 } 1070 1071 /* 1072 * Error reporting function. Use it like printf. If formats the message 1073 * into a buffer, and sets things up so that the next call to dlerror() 1074 * will return the message. 1075 */ 1076 void 1077 _rtld_error(const char *fmt, ...) 1078 { 1079 va_list ap; 1080 1081 va_start(ap, fmt); 1082 rtld_vsnprintf(lockinfo.dlerror_loc(), lockinfo.dlerror_loc_sz, 1083 fmt, ap); 1084 va_end(ap); 1085 *lockinfo.dlerror_seen() = 0; 1086 dbg("rtld_error: %s", lockinfo.dlerror_loc()); 1087 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, lockinfo.dlerror_loc()); 1088 } 1089 1090 /* 1091 * Return a dynamically-allocated copy of the current error message, if any. 1092 */ 1093 static struct dlerror_save * 1094 errmsg_save(void) 1095 { 1096 struct dlerror_save *res; 1097 1098 res = xmalloc(sizeof(*res)); 1099 res->seen = *lockinfo.dlerror_seen(); 1100 if (res->seen == 0) 1101 res->msg = xstrdup(lockinfo.dlerror_loc()); 1102 return (res); 1103 } 1104 1105 /* 1106 * Restore the current error message from a copy which was previously saved 1107 * by errmsg_save(). The copy is freed. 1108 */ 1109 static void 1110 errmsg_restore(struct dlerror_save *saved_msg) 1111 { 1112 if (saved_msg == NULL || saved_msg->seen == 1) { 1113 *lockinfo.dlerror_seen() = 1; 1114 } else { 1115 *lockinfo.dlerror_seen() = 0; 1116 strlcpy(lockinfo.dlerror_loc(), saved_msg->msg, 1117 lockinfo.dlerror_loc_sz); 1118 free(saved_msg->msg); 1119 } 1120 free(saved_msg); 1121 } 1122 1123 static const char * 1124 basename(const char *name) 1125 { 1126 const char *p; 1127 1128 p = strrchr(name, '/'); 1129 return (p != NULL ? p + 1 : name); 1130 } 1131 1132 static struct utsname uts; 1133 1134 static char * 1135 origin_subst_one(Obj_Entry *obj, char *real, const char *kw, 1136 const char *subst, bool may_free) 1137 { 1138 char *p, *p1, *res, *resp; 1139 int subst_len, kw_len, subst_count, old_len, new_len; 1140 1141 kw_len = strlen(kw); 1142 1143 /* 1144 * First, count the number of the keyword occurrences, to 1145 * preallocate the final string. 1146 */ 1147 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 1148 p1 = strstr(p, kw); 1149 if (p1 == NULL) 1150 break; 1151 } 1152 1153 /* 1154 * If the keyword is not found, just return. 1155 * 1156 * Return non-substituted string if resolution failed. We 1157 * cannot do anything more reasonable, the failure mode of the 1158 * caller is unresolved library anyway. 1159 */ 1160 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj))) 1161 return (may_free ? real : xstrdup(real)); 1162 if (obj != NULL) 1163 subst = obj->origin_path; 1164 1165 /* 1166 * There is indeed something to substitute. Calculate the 1167 * length of the resulting string, and allocate it. 1168 */ 1169 subst_len = strlen(subst); 1170 old_len = strlen(real); 1171 new_len = old_len + (subst_len - kw_len) * subst_count; 1172 res = xmalloc(new_len + 1); 1173 1174 /* 1175 * Now, execute the substitution loop. 1176 */ 1177 for (p = real, resp = res, *resp = '\0';;) { 1178 p1 = strstr(p, kw); 1179 if (p1 != NULL) { 1180 /* Copy the prefix before keyword. */ 1181 memcpy(resp, p, p1 - p); 1182 resp += p1 - p; 1183 /* Keyword replacement. */ 1184 memcpy(resp, subst, subst_len); 1185 resp += subst_len; 1186 *resp = '\0'; 1187 p = p1 + kw_len; 1188 } else 1189 break; 1190 } 1191 1192 /* Copy to the end of string and finish. */ 1193 strcat(resp, p); 1194 if (may_free) 1195 free(real); 1196 return (res); 1197 } 1198 1199 static const struct { 1200 const char *kw; 1201 bool pass_obj; 1202 const char *subst; 1203 } tokens[] = { 1204 { .kw = "$ORIGIN", .pass_obj = true, .subst = NULL }, 1205 { .kw = "${ORIGIN}", .pass_obj = true, .subst = NULL }, 1206 { .kw = "$OSNAME", .pass_obj = false, .subst = uts.sysname }, 1207 { .kw = "${OSNAME}", .pass_obj = false, .subst = uts.sysname }, 1208 { .kw = "$OSREL", .pass_obj = false, .subst = uts.release }, 1209 { .kw = "${OSREL}", .pass_obj = false, .subst = uts.release }, 1210 { .kw = "$PLATFORM", .pass_obj = false, .subst = uts.machine }, 1211 { .kw = "${PLATFORM}", .pass_obj = false, .subst = uts.machine }, 1212 { .kw = "$LIB", .pass_obj = false, .subst = TOKEN_LIB }, 1213 { .kw = "${LIB}", .pass_obj = false, .subst = TOKEN_LIB }, 1214 }; 1215 1216 static char * 1217 origin_subst(Obj_Entry *obj, const char *real) 1218 { 1219 char *res; 1220 int i; 1221 1222 if (obj == NULL || !trust) 1223 return (xstrdup(real)); 1224 if (uts.sysname[0] == '\0') { 1225 if (uname(&uts) != 0) { 1226 _rtld_error("utsname failed: %d", errno); 1227 return (NULL); 1228 } 1229 } 1230 1231 /* __DECONST is safe here since without may_free real is unchanged */ 1232 res = __DECONST(char *, real); 1233 for (i = 0; i < (int)nitems(tokens); i++) { 1234 res = origin_subst_one(tokens[i].pass_obj ? obj : NULL, 1235 res, tokens[i].kw, tokens[i].subst, i != 0); 1236 } 1237 return (res); 1238 } 1239 1240 void 1241 rtld_die(void) 1242 { 1243 const char *msg = dlerror(); 1244 1245 if (msg == NULL) 1246 msg = "Fatal error"; 1247 rtld_fdputstr(STDERR_FILENO, _BASENAME_RTLD ": "); 1248 rtld_fdputstr(STDERR_FILENO, msg); 1249 rtld_fdputchar(STDERR_FILENO, '\n'); 1250 _exit(1); 1251 } 1252 1253 /* 1254 * Process a shared object's DYNAMIC section, and save the important 1255 * information in its Obj_Entry structure. 1256 */ 1257 static void 1258 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 1259 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 1260 { 1261 const Elf_Dyn *dynp; 1262 Needed_Entry **needed_tail = &obj->needed; 1263 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 1264 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 1265 const Elf_Hashelt *hashtab; 1266 const Elf32_Word *hashval; 1267 Elf32_Word bkt, nmaskwords; 1268 int bloom_size32; 1269 int plttype = DT_REL; 1270 1271 *dyn_rpath = NULL; 1272 *dyn_soname = NULL; 1273 *dyn_runpath = NULL; 1274 1275 obj->bind_now = false; 1276 dynp = obj->dynamic; 1277 if (dynp == NULL) 1278 return; 1279 for (; dynp->d_tag != DT_NULL; dynp++) { 1280 switch (dynp->d_tag) { 1281 1282 case DT_REL: 1283 obj->rel = (const Elf_Rel *)(obj->relocbase + dynp->d_un.d_ptr); 1284 break; 1285 1286 case DT_RELSZ: 1287 obj->relsize = dynp->d_un.d_val; 1288 break; 1289 1290 case DT_RELENT: 1291 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 1292 break; 1293 1294 case DT_JMPREL: 1295 obj->pltrel = (const Elf_Rel *) 1296 (obj->relocbase + dynp->d_un.d_ptr); 1297 break; 1298 1299 case DT_PLTRELSZ: 1300 obj->pltrelsize = dynp->d_un.d_val; 1301 break; 1302 1303 case DT_RELA: 1304 obj->rela = (const Elf_Rela *)(obj->relocbase + dynp->d_un.d_ptr); 1305 break; 1306 1307 case DT_RELASZ: 1308 obj->relasize = dynp->d_un.d_val; 1309 break; 1310 1311 case DT_RELAENT: 1312 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 1313 break; 1314 1315 case DT_RELR: 1316 obj->relr = (const Elf_Relr *)(obj->relocbase + dynp->d_un.d_ptr); 1317 break; 1318 1319 case DT_RELRSZ: 1320 obj->relrsize = dynp->d_un.d_val; 1321 break; 1322 1323 case DT_RELRENT: 1324 assert(dynp->d_un.d_val == sizeof(Elf_Relr)); 1325 break; 1326 1327 case DT_PLTREL: 1328 plttype = dynp->d_un.d_val; 1329 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 1330 break; 1331 1332 case DT_SYMTAB: 1333 obj->symtab = (const Elf_Sym *) 1334 (obj->relocbase + dynp->d_un.d_ptr); 1335 break; 1336 1337 case DT_SYMENT: 1338 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 1339 break; 1340 1341 case DT_STRTAB: 1342 obj->strtab = (const char *)(obj->relocbase + dynp->d_un.d_ptr); 1343 break; 1344 1345 case DT_STRSZ: 1346 obj->strsize = dynp->d_un.d_val; 1347 break; 1348 1349 case DT_VERNEED: 1350 obj->verneed = (const Elf_Verneed *)(obj->relocbase + 1351 dynp->d_un.d_val); 1352 break; 1353 1354 case DT_VERNEEDNUM: 1355 obj->verneednum = dynp->d_un.d_val; 1356 break; 1357 1358 case DT_VERDEF: 1359 obj->verdef = (const Elf_Verdef *)(obj->relocbase + 1360 dynp->d_un.d_val); 1361 break; 1362 1363 case DT_VERDEFNUM: 1364 obj->verdefnum = dynp->d_un.d_val; 1365 break; 1366 1367 case DT_VERSYM: 1368 obj->versyms = (const Elf_Versym *)(obj->relocbase + 1369 dynp->d_un.d_val); 1370 break; 1371 1372 case DT_HASH: 1373 { 1374 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1375 dynp->d_un.d_ptr); 1376 obj->nbuckets = hashtab[0]; 1377 obj->nchains = hashtab[1]; 1378 obj->buckets = hashtab + 2; 1379 obj->chains = obj->buckets + obj->nbuckets; 1380 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 1381 obj->buckets != NULL; 1382 } 1383 break; 1384 1385 case DT_GNU_HASH: 1386 { 1387 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1388 dynp->d_un.d_ptr); 1389 obj->nbuckets_gnu = hashtab[0]; 1390 obj->symndx_gnu = hashtab[1]; 1391 nmaskwords = hashtab[2]; 1392 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1393 obj->maskwords_bm_gnu = nmaskwords - 1; 1394 obj->shift2_gnu = hashtab[3]; 1395 obj->bloom_gnu = (const Elf_Addr *)(hashtab + 4); 1396 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1397 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1398 obj->symndx_gnu; 1399 /* Number of bitmask words is required to be power of 2 */ 1400 obj->valid_hash_gnu = powerof2(nmaskwords) && 1401 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1402 } 1403 break; 1404 1405 case DT_NEEDED: 1406 if (!obj->rtld) { 1407 Needed_Entry *nep = NEW(Needed_Entry); 1408 nep->name = dynp->d_un.d_val; 1409 nep->obj = NULL; 1410 nep->next = NULL; 1411 1412 *needed_tail = nep; 1413 needed_tail = &nep->next; 1414 } 1415 break; 1416 1417 case DT_FILTER: 1418 if (!obj->rtld) { 1419 Needed_Entry *nep = NEW(Needed_Entry); 1420 nep->name = dynp->d_un.d_val; 1421 nep->obj = NULL; 1422 nep->next = NULL; 1423 1424 *needed_filtees_tail = nep; 1425 needed_filtees_tail = &nep->next; 1426 1427 if (obj->linkmap.l_refname == NULL) 1428 obj->linkmap.l_refname = (char *)dynp->d_un.d_val; 1429 } 1430 break; 1431 1432 case DT_AUXILIARY: 1433 if (!obj->rtld) { 1434 Needed_Entry *nep = NEW(Needed_Entry); 1435 nep->name = dynp->d_un.d_val; 1436 nep->obj = NULL; 1437 nep->next = NULL; 1438 1439 *needed_aux_filtees_tail = nep; 1440 needed_aux_filtees_tail = &nep->next; 1441 } 1442 break; 1443 1444 case DT_PLTGOT: 1445 obj->pltgot = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr); 1446 break; 1447 1448 case DT_TEXTREL: 1449 obj->textrel = true; 1450 break; 1451 1452 case DT_SYMBOLIC: 1453 obj->symbolic = true; 1454 break; 1455 1456 case DT_RPATH: 1457 /* 1458 * We have to wait until later to process this, because we 1459 * might not have gotten the address of the string table yet. 1460 */ 1461 *dyn_rpath = dynp; 1462 break; 1463 1464 case DT_SONAME: 1465 *dyn_soname = dynp; 1466 break; 1467 1468 case DT_RUNPATH: 1469 *dyn_runpath = dynp; 1470 break; 1471 1472 case DT_INIT: 1473 obj->init = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1474 break; 1475 1476 case DT_PREINIT_ARRAY: 1477 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1478 break; 1479 1480 case DT_PREINIT_ARRAYSZ: 1481 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1482 break; 1483 1484 case DT_INIT_ARRAY: 1485 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1486 break; 1487 1488 case DT_INIT_ARRAYSZ: 1489 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1490 break; 1491 1492 case DT_FINI: 1493 obj->fini = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1494 break; 1495 1496 case DT_FINI_ARRAY: 1497 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1498 break; 1499 1500 case DT_FINI_ARRAYSZ: 1501 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1502 break; 1503 1504 case DT_DEBUG: 1505 if (!early) 1506 dbg("Filling in DT_DEBUG entry"); 1507 (__DECONST(Elf_Dyn *, dynp))->d_un.d_ptr = (Elf_Addr)&r_debug; 1508 break; 1509 1510 case DT_FLAGS: 1511 if (dynp->d_un.d_val & DF_ORIGIN) 1512 obj->z_origin = true; 1513 if (dynp->d_un.d_val & DF_SYMBOLIC) 1514 obj->symbolic = true; 1515 if (dynp->d_un.d_val & DF_TEXTREL) 1516 obj->textrel = true; 1517 if (dynp->d_un.d_val & DF_BIND_NOW) 1518 obj->bind_now = true; 1519 if (dynp->d_un.d_val & DF_STATIC_TLS) 1520 obj->static_tls = true; 1521 break; 1522 1523 #ifdef __powerpc__ 1524 #ifdef __powerpc64__ 1525 case DT_PPC64_GLINK: 1526 obj->glink = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1527 break; 1528 #else 1529 case DT_PPC_GOT: 1530 obj->gotptr = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr); 1531 break; 1532 #endif 1533 #endif 1534 1535 case DT_FLAGS_1: 1536 if (dynp->d_un.d_val & DF_1_NOOPEN) 1537 obj->z_noopen = true; 1538 if (dynp->d_un.d_val & DF_1_ORIGIN) 1539 obj->z_origin = true; 1540 if (dynp->d_un.d_val & DF_1_GLOBAL) 1541 obj->z_global = true; 1542 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1543 obj->bind_now = true; 1544 if (dynp->d_un.d_val & DF_1_NODELETE) 1545 obj->z_nodelete = true; 1546 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1547 obj->z_loadfltr = true; 1548 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1549 obj->z_interpose = true; 1550 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1551 obj->z_nodeflib = true; 1552 if (dynp->d_un.d_val & DF_1_PIE) 1553 obj->z_pie = true; 1554 break; 1555 1556 default: 1557 if (!early) { 1558 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1559 (long)dynp->d_tag); 1560 } 1561 break; 1562 } 1563 } 1564 1565 obj->traced = false; 1566 1567 if (plttype == DT_RELA) { 1568 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1569 obj->pltrel = NULL; 1570 obj->pltrelasize = obj->pltrelsize; 1571 obj->pltrelsize = 0; 1572 } 1573 1574 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1575 if (obj->valid_hash_sysv) 1576 obj->dynsymcount = obj->nchains; 1577 else if (obj->valid_hash_gnu) { 1578 obj->dynsymcount = 0; 1579 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1580 if (obj->buckets_gnu[bkt] == 0) 1581 continue; 1582 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1583 do 1584 obj->dynsymcount++; 1585 while ((*hashval++ & 1u) == 0); 1586 } 1587 obj->dynsymcount += obj->symndx_gnu; 1588 } 1589 1590 if (obj->linkmap.l_refname != NULL) 1591 obj->linkmap.l_refname = obj->strtab + (unsigned long)obj-> 1592 linkmap.l_refname; 1593 } 1594 1595 static bool 1596 obj_resolve_origin(Obj_Entry *obj) 1597 { 1598 1599 if (obj->origin_path != NULL) 1600 return (true); 1601 obj->origin_path = xmalloc(PATH_MAX); 1602 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1); 1603 } 1604 1605 static bool 1606 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1607 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1608 { 1609 1610 if (obj->z_origin && !obj_resolve_origin(obj)) 1611 return (false); 1612 1613 if (dyn_runpath != NULL) { 1614 obj->runpath = (const char *)obj->strtab + dyn_runpath->d_un.d_val; 1615 obj->runpath = origin_subst(obj, obj->runpath); 1616 } else if (dyn_rpath != NULL) { 1617 obj->rpath = (const char *)obj->strtab + dyn_rpath->d_un.d_val; 1618 obj->rpath = origin_subst(obj, obj->rpath); 1619 } 1620 if (dyn_soname != NULL) 1621 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1622 return (true); 1623 } 1624 1625 static bool 1626 digest_dynamic(Obj_Entry *obj, int early) 1627 { 1628 const Elf_Dyn *dyn_rpath; 1629 const Elf_Dyn *dyn_soname; 1630 const Elf_Dyn *dyn_runpath; 1631 1632 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1633 return (digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath)); 1634 } 1635 1636 /* 1637 * Process a shared object's program header. This is used only for the 1638 * main program, when the kernel has already loaded the main program 1639 * into memory before calling the dynamic linker. It creates and 1640 * returns an Obj_Entry structure. 1641 */ 1642 static Obj_Entry * 1643 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1644 { 1645 Obj_Entry *obj; 1646 const Elf_Phdr *phlimit = phdr + phnum; 1647 const Elf_Phdr *ph; 1648 Elf_Addr note_start, note_end; 1649 int nsegs = 0; 1650 1651 obj = obj_new(); 1652 for (ph = phdr; ph < phlimit; ph++) { 1653 if (ph->p_type != PT_PHDR) 1654 continue; 1655 1656 obj->phdr = phdr; 1657 obj->phsize = ph->p_memsz; 1658 obj->relocbase = __DECONST(char *, phdr) - ph->p_vaddr; 1659 break; 1660 } 1661 1662 obj->stack_flags = PF_X | PF_R | PF_W; 1663 1664 for (ph = phdr; ph < phlimit; ph++) { 1665 switch (ph->p_type) { 1666 1667 case PT_INTERP: 1668 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1669 break; 1670 1671 case PT_LOAD: 1672 if (nsegs == 0) { /* First load segment */ 1673 obj->vaddrbase = rtld_trunc_page(ph->p_vaddr); 1674 obj->mapbase = obj->vaddrbase + obj->relocbase; 1675 } else { /* Last load segment */ 1676 obj->mapsize = rtld_round_page(ph->p_vaddr + ph->p_memsz) - 1677 obj->vaddrbase; 1678 } 1679 nsegs++; 1680 break; 1681 1682 case PT_DYNAMIC: 1683 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1684 break; 1685 1686 case PT_TLS: 1687 obj->tlsindex = 1; 1688 obj->tlssize = ph->p_memsz; 1689 obj->tlsalign = ph->p_align; 1690 obj->tlsinitsize = ph->p_filesz; 1691 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1692 obj->tlspoffset = ph->p_offset; 1693 break; 1694 1695 case PT_GNU_STACK: 1696 obj->stack_flags = ph->p_flags; 1697 break; 1698 1699 case PT_GNU_RELRO: 1700 obj->relro_page = obj->relocbase + rtld_trunc_page(ph->p_vaddr); 1701 obj->relro_size = rtld_trunc_page(ph->p_vaddr + ph->p_memsz) - 1702 rtld_trunc_page(ph->p_vaddr); 1703 break; 1704 1705 case PT_NOTE: 1706 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1707 note_end = note_start + ph->p_filesz; 1708 digest_notes(obj, note_start, note_end); 1709 break; 1710 } 1711 } 1712 if (nsegs < 1) { 1713 _rtld_error("%s: too few PT_LOAD segments", path); 1714 return (NULL); 1715 } 1716 1717 obj->entry = entry; 1718 return (obj); 1719 } 1720 1721 void 1722 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1723 { 1724 const Elf_Note *note; 1725 const char *note_name; 1726 uintptr_t p; 1727 1728 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1729 note = (const Elf_Note *)((const char *)(note + 1) + 1730 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1731 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1732 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1733 note->n_descsz != sizeof(int32_t)) 1734 continue; 1735 if (note->n_type != NT_FREEBSD_ABI_TAG && 1736 note->n_type != NT_FREEBSD_FEATURE_CTL && 1737 note->n_type != NT_FREEBSD_NOINIT_TAG) 1738 continue; 1739 note_name = (const char *)(note + 1); 1740 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1741 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1742 continue; 1743 switch (note->n_type) { 1744 case NT_FREEBSD_ABI_TAG: 1745 /* FreeBSD osrel note */ 1746 p = (uintptr_t)(note + 1); 1747 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1748 obj->osrel = *(const int32_t *)(p); 1749 dbg("note osrel %d", obj->osrel); 1750 break; 1751 case NT_FREEBSD_FEATURE_CTL: 1752 /* FreeBSD ABI feature control note */ 1753 p = (uintptr_t)(note + 1); 1754 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1755 obj->fctl0 = *(const uint32_t *)(p); 1756 dbg("note fctl0 %#x", obj->fctl0); 1757 break; 1758 case NT_FREEBSD_NOINIT_TAG: 1759 /* FreeBSD 'crt does not call init' note */ 1760 obj->crt_no_init = true; 1761 dbg("note crt_no_init"); 1762 break; 1763 } 1764 } 1765 } 1766 1767 static Obj_Entry * 1768 dlcheck(void *handle) 1769 { 1770 Obj_Entry *obj; 1771 1772 TAILQ_FOREACH(obj, &obj_list, next) { 1773 if (obj == (Obj_Entry *) handle) 1774 break; 1775 } 1776 1777 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1778 _rtld_error("Invalid shared object handle %p", handle); 1779 return (NULL); 1780 } 1781 return (obj); 1782 } 1783 1784 /* 1785 * If the given object is already in the donelist, return true. Otherwise 1786 * add the object to the list and return false. 1787 */ 1788 static bool 1789 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1790 { 1791 unsigned int i; 1792 1793 for (i = 0; i < dlp->num_used; i++) 1794 if (dlp->objs[i] == obj) 1795 return (true); 1796 /* 1797 * Our donelist allocation should always be sufficient. But if 1798 * our threads locking isn't working properly, more shared objects 1799 * could have been loaded since we allocated the list. That should 1800 * never happen, but we'll handle it properly just in case it does. 1801 */ 1802 if (dlp->num_used < dlp->num_alloc) 1803 dlp->objs[dlp->num_used++] = obj; 1804 return (false); 1805 } 1806 1807 /* 1808 * SysV hash function for symbol table lookup. It is a slightly optimized 1809 * version of the hash specified by the System V ABI. 1810 */ 1811 Elf32_Word 1812 elf_hash(const char *name) 1813 { 1814 const unsigned char *p = (const unsigned char *)name; 1815 Elf32_Word h = 0; 1816 1817 while (*p != '\0') { 1818 h = (h << 4) + *p++; 1819 h ^= (h >> 24) & 0xf0; 1820 } 1821 return (h & 0x0fffffff); 1822 } 1823 1824 /* 1825 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1826 * unsigned in case it's implemented with a wider type. 1827 */ 1828 static uint32_t 1829 gnu_hash(const char *s) 1830 { 1831 uint32_t h; 1832 unsigned char c; 1833 1834 h = 5381; 1835 for (c = *s; c != '\0'; c = *++s) 1836 h = h * 33 + c; 1837 return (h & 0xffffffff); 1838 } 1839 1840 1841 /* 1842 * Find the library with the given name, and return its full pathname. 1843 * The returned string is dynamically allocated. Generates an error 1844 * message and returns NULL if the library cannot be found. 1845 * 1846 * If the second argument is non-NULL, then it refers to an already- 1847 * loaded shared object, whose library search path will be searched. 1848 * 1849 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1850 * descriptor (which is close-on-exec) will be passed out via the third 1851 * argument. 1852 * 1853 * The search order is: 1854 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1855 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1856 * LD_LIBRARY_PATH 1857 * DT_RUNPATH in the referencing file 1858 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1859 * from list) 1860 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1861 * 1862 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1863 */ 1864 static char * 1865 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1866 { 1867 char *pathname, *refobj_path; 1868 const char *name; 1869 bool nodeflib, objgiven; 1870 1871 objgiven = refobj != NULL; 1872 1873 if (libmap_disable || !objgiven || 1874 (name = lm_find(refobj->path, xname)) == NULL) 1875 name = xname; 1876 1877 if (strchr(name, '/') != NULL) { /* Hard coded pathname */ 1878 if (name[0] != '/' && !trust) { 1879 _rtld_error("Absolute pathname required " 1880 "for shared object \"%s\"", name); 1881 return (NULL); 1882 } 1883 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1884 __DECONST(char *, name))); 1885 } 1886 1887 dbg(" Searching for \"%s\"", name); 1888 refobj_path = objgiven ? refobj->path : NULL; 1889 1890 /* 1891 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1892 * back to pre-conforming behaviour if user requested so with 1893 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1894 * nodeflib. 1895 */ 1896 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1897 pathname = search_library_path(name, ld_library_path, 1898 refobj_path, fdp); 1899 if (pathname != NULL) 1900 return (pathname); 1901 if (refobj != NULL) { 1902 pathname = search_library_path(name, refobj->rpath, 1903 refobj_path, fdp); 1904 if (pathname != NULL) 1905 return (pathname); 1906 } 1907 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1908 if (pathname != NULL) 1909 return (pathname); 1910 pathname = search_library_path(name, gethints(false), 1911 refobj_path, fdp); 1912 if (pathname != NULL) 1913 return (pathname); 1914 pathname = search_library_path(name, ld_standard_library_path, 1915 refobj_path, fdp); 1916 if (pathname != NULL) 1917 return (pathname); 1918 } else { 1919 nodeflib = objgiven ? refobj->z_nodeflib : false; 1920 if (objgiven) { 1921 pathname = search_library_path(name, refobj->rpath, 1922 refobj->path, fdp); 1923 if (pathname != NULL) 1924 return (pathname); 1925 } 1926 if (objgiven && refobj->runpath == NULL && refobj != obj_main) { 1927 pathname = search_library_path(name, obj_main->rpath, 1928 refobj_path, fdp); 1929 if (pathname != NULL) 1930 return (pathname); 1931 } 1932 pathname = search_library_path(name, ld_library_path, 1933 refobj_path, fdp); 1934 if (pathname != NULL) 1935 return (pathname); 1936 if (objgiven) { 1937 pathname = search_library_path(name, refobj->runpath, 1938 refobj_path, fdp); 1939 if (pathname != NULL) 1940 return (pathname); 1941 } 1942 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1943 if (pathname != NULL) 1944 return (pathname); 1945 pathname = search_library_path(name, gethints(nodeflib), 1946 refobj_path, fdp); 1947 if (pathname != NULL) 1948 return (pathname); 1949 if (objgiven && !nodeflib) { 1950 pathname = search_library_path(name, 1951 ld_standard_library_path, refobj_path, fdp); 1952 if (pathname != NULL) 1953 return (pathname); 1954 } 1955 } 1956 1957 if (objgiven && refobj->path != NULL) { 1958 _rtld_error("Shared object \"%s\" not found, " 1959 "required by \"%s\"", name, basename(refobj->path)); 1960 } else { 1961 _rtld_error("Shared object \"%s\" not found", name); 1962 } 1963 return (NULL); 1964 } 1965 1966 /* 1967 * Given a symbol number in a referencing object, find the corresponding 1968 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1969 * no definition was found. Returns a pointer to the Obj_Entry of the 1970 * defining object via the reference parameter DEFOBJ_OUT. 1971 */ 1972 const Elf_Sym * 1973 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1974 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1975 RtldLockState *lockstate) 1976 { 1977 const Elf_Sym *ref; 1978 const Elf_Sym *def; 1979 const Obj_Entry *defobj; 1980 const Ver_Entry *ve; 1981 SymLook req; 1982 const char *name; 1983 int res; 1984 1985 /* 1986 * If we have already found this symbol, get the information from 1987 * the cache. 1988 */ 1989 if (symnum >= refobj->dynsymcount) 1990 return (NULL); /* Bad object */ 1991 if (cache != NULL && cache[symnum].sym != NULL) { 1992 *defobj_out = cache[symnum].obj; 1993 return (cache[symnum].sym); 1994 } 1995 1996 ref = refobj->symtab + symnum; 1997 name = refobj->strtab + ref->st_name; 1998 def = NULL; 1999 defobj = NULL; 2000 ve = NULL; 2001 2002 /* 2003 * We don't have to do a full scale lookup if the symbol is local. 2004 * We know it will bind to the instance in this load module; to 2005 * which we already have a pointer (ie ref). By not doing a lookup, 2006 * we not only improve performance, but it also avoids unresolvable 2007 * symbols when local symbols are not in the hash table. This has 2008 * been seen with the ia64 toolchain. 2009 */ 2010 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 2011 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 2012 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 2013 symnum); 2014 } 2015 symlook_init(&req, name); 2016 req.flags = flags; 2017 ve = req.ventry = fetch_ventry(refobj, symnum); 2018 req.lockstate = lockstate; 2019 res = symlook_default(&req, refobj); 2020 if (res == 0) { 2021 def = req.sym_out; 2022 defobj = req.defobj_out; 2023 } 2024 } else { 2025 def = ref; 2026 defobj = refobj; 2027 } 2028 2029 /* 2030 * If we found no definition and the reference is weak, treat the 2031 * symbol as having the value zero. 2032 */ 2033 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 2034 def = &sym_zero; 2035 defobj = obj_main; 2036 } 2037 2038 if (def != NULL) { 2039 *defobj_out = defobj; 2040 /* Record the information in the cache to avoid subsequent lookups. */ 2041 if (cache != NULL) { 2042 cache[symnum].sym = def; 2043 cache[symnum].obj = defobj; 2044 } 2045 } else { 2046 if (refobj != &obj_rtld) 2047 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name, 2048 ve != NULL ? "@" : "", ve != NULL ? ve->name : ""); 2049 } 2050 return (def); 2051 } 2052 2053 /* 2054 * Return the search path from the ldconfig hints file, reading it if 2055 * necessary. If nostdlib is true, then the default search paths are 2056 * not added to result. 2057 * 2058 * Returns NULL if there are problems with the hints file, 2059 * or if the search path there is empty. 2060 */ 2061 static const char * 2062 gethints(bool nostdlib) 2063 { 2064 static char *filtered_path; 2065 static const char *hints; 2066 static struct elfhints_hdr hdr; 2067 struct fill_search_info_args sargs, hargs; 2068 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 2069 struct dl_serpath *SLPpath, *hintpath; 2070 char *p; 2071 struct stat hint_stat; 2072 unsigned int SLPndx, hintndx, fndx, fcount; 2073 int fd; 2074 size_t flen; 2075 uint32_t dl; 2076 bool skip; 2077 2078 /* First call, read the hints file */ 2079 if (hints == NULL) { 2080 /* Keep from trying again in case the hints file is bad. */ 2081 hints = ""; 2082 2083 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 2084 return (NULL); 2085 2086 /* 2087 * Check of hdr.dirlistlen value against type limit 2088 * intends to pacify static analyzers. Further 2089 * paranoia leads to checks that dirlist is fully 2090 * contained in the file range. 2091 */ 2092 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 2093 hdr.magic != ELFHINTS_MAGIC || 2094 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 || 2095 fstat(fd, &hint_stat) == -1) { 2096 cleanup1: 2097 close(fd); 2098 hdr.dirlistlen = 0; 2099 return (NULL); 2100 } 2101 dl = hdr.strtab; 2102 if (dl + hdr.dirlist < dl) 2103 goto cleanup1; 2104 dl += hdr.dirlist; 2105 if (dl + hdr.dirlistlen < dl) 2106 goto cleanup1; 2107 dl += hdr.dirlistlen; 2108 if (dl > hint_stat.st_size) 2109 goto cleanup1; 2110 p = xmalloc(hdr.dirlistlen + 1); 2111 if (pread(fd, p, hdr.dirlistlen + 1, 2112 hdr.strtab + hdr.dirlist) != (ssize_t)hdr.dirlistlen + 1 || 2113 p[hdr.dirlistlen] != '\0') { 2114 free(p); 2115 goto cleanup1; 2116 } 2117 hints = p; 2118 close(fd); 2119 } 2120 2121 /* 2122 * If caller agreed to receive list which includes the default 2123 * paths, we are done. Otherwise, if we still did not 2124 * calculated filtered result, do it now. 2125 */ 2126 if (!nostdlib) 2127 return (hints[0] != '\0' ? hints : NULL); 2128 if (filtered_path != NULL) 2129 goto filt_ret; 2130 2131 /* 2132 * Obtain the list of all configured search paths, and the 2133 * list of the default paths. 2134 * 2135 * First estimate the size of the results. 2136 */ 2137 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2138 smeta.dls_cnt = 0; 2139 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2140 hmeta.dls_cnt = 0; 2141 2142 sargs.request = RTLD_DI_SERINFOSIZE; 2143 sargs.serinfo = &smeta; 2144 hargs.request = RTLD_DI_SERINFOSIZE; 2145 hargs.serinfo = &hmeta; 2146 2147 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 2148 &sargs); 2149 path_enumerate(hints, fill_search_info, NULL, &hargs); 2150 2151 SLPinfo = xmalloc(smeta.dls_size); 2152 hintinfo = xmalloc(hmeta.dls_size); 2153 2154 /* 2155 * Next fetch both sets of paths. 2156 */ 2157 sargs.request = RTLD_DI_SERINFO; 2158 sargs.serinfo = SLPinfo; 2159 sargs.serpath = &SLPinfo->dls_serpath[0]; 2160 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 2161 2162 hargs.request = RTLD_DI_SERINFO; 2163 hargs.serinfo = hintinfo; 2164 hargs.serpath = &hintinfo->dls_serpath[0]; 2165 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 2166 2167 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 2168 &sargs); 2169 path_enumerate(hints, fill_search_info, NULL, &hargs); 2170 2171 /* 2172 * Now calculate the difference between two sets, by excluding 2173 * standard paths from the full set. 2174 */ 2175 fndx = 0; 2176 fcount = 0; 2177 filtered_path = xmalloc(hdr.dirlistlen + 1); 2178 hintpath = &hintinfo->dls_serpath[0]; 2179 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 2180 skip = false; 2181 SLPpath = &SLPinfo->dls_serpath[0]; 2182 /* 2183 * Check each standard path against current. 2184 */ 2185 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 2186 /* matched, skip the path */ 2187 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 2188 skip = true; 2189 break; 2190 } 2191 } 2192 if (skip) 2193 continue; 2194 /* 2195 * Not matched against any standard path, add the path 2196 * to result. Separate consequtive paths with ':'. 2197 */ 2198 if (fcount > 0) { 2199 filtered_path[fndx] = ':'; 2200 fndx++; 2201 } 2202 fcount++; 2203 flen = strlen(hintpath->dls_name); 2204 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 2205 fndx += flen; 2206 } 2207 filtered_path[fndx] = '\0'; 2208 2209 free(SLPinfo); 2210 free(hintinfo); 2211 2212 filt_ret: 2213 return (filtered_path[0] != '\0' ? filtered_path : NULL); 2214 } 2215 2216 static void 2217 init_dag(Obj_Entry *root) 2218 { 2219 const Needed_Entry *needed; 2220 const Objlist_Entry *elm; 2221 DoneList donelist; 2222 2223 if (root->dag_inited) 2224 return; 2225 donelist_init(&donelist); 2226 2227 /* Root object belongs to own DAG. */ 2228 objlist_push_tail(&root->dldags, root); 2229 objlist_push_tail(&root->dagmembers, root); 2230 donelist_check(&donelist, root); 2231 2232 /* 2233 * Add dependencies of root object to DAG in breadth order 2234 * by exploiting the fact that each new object get added 2235 * to the tail of the dagmembers list. 2236 */ 2237 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2238 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 2239 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 2240 continue; 2241 objlist_push_tail(&needed->obj->dldags, root); 2242 objlist_push_tail(&root->dagmembers, needed->obj); 2243 } 2244 } 2245 root->dag_inited = true; 2246 } 2247 2248 static void 2249 init_marker(Obj_Entry *marker) 2250 { 2251 2252 bzero(marker, sizeof(*marker)); 2253 marker->marker = true; 2254 } 2255 2256 Obj_Entry * 2257 globallist_curr(const Obj_Entry *obj) 2258 { 2259 2260 for (;;) { 2261 if (obj == NULL) 2262 return (NULL); 2263 if (!obj->marker) 2264 return (__DECONST(Obj_Entry *, obj)); 2265 obj = TAILQ_PREV(obj, obj_entry_q, next); 2266 } 2267 } 2268 2269 Obj_Entry * 2270 globallist_next(const Obj_Entry *obj) 2271 { 2272 2273 for (;;) { 2274 obj = TAILQ_NEXT(obj, next); 2275 if (obj == NULL) 2276 return (NULL); 2277 if (!obj->marker) 2278 return (__DECONST(Obj_Entry *, obj)); 2279 } 2280 } 2281 2282 /* Prevent the object from being unmapped while the bind lock is dropped. */ 2283 static void 2284 hold_object(Obj_Entry *obj) 2285 { 2286 2287 obj->holdcount++; 2288 } 2289 2290 static void 2291 unhold_object(Obj_Entry *obj) 2292 { 2293 2294 assert(obj->holdcount > 0); 2295 if (--obj->holdcount == 0 && obj->unholdfree) 2296 release_object(obj); 2297 } 2298 2299 static void 2300 process_z(Obj_Entry *root) 2301 { 2302 const Objlist_Entry *elm; 2303 Obj_Entry *obj; 2304 2305 /* 2306 * Walk over object DAG and process every dependent object 2307 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 2308 * to grow their own DAG. 2309 * 2310 * For DF_1_GLOBAL, DAG is required for symbol lookups in 2311 * symlook_global() to work. 2312 * 2313 * For DF_1_NODELETE, the DAG should have its reference upped. 2314 */ 2315 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2316 obj = elm->obj; 2317 if (obj == NULL) 2318 continue; 2319 if (obj->z_nodelete && !obj->ref_nodel) { 2320 dbg("obj %s -z nodelete", obj->path); 2321 init_dag(obj); 2322 ref_dag(obj); 2323 obj->ref_nodel = true; 2324 } 2325 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 2326 dbg("obj %s -z global", obj->path); 2327 objlist_push_tail(&list_global, obj); 2328 init_dag(obj); 2329 } 2330 } 2331 } 2332 2333 static void 2334 parse_rtld_phdr(Obj_Entry *obj) 2335 { 2336 const Elf_Phdr *ph; 2337 Elf_Addr note_start, note_end; 2338 2339 obj->stack_flags = PF_X | PF_R | PF_W; 2340 for (ph = obj->phdr; (const char *)ph < (const char *)obj->phdr + 2341 obj->phsize; ph++) { 2342 switch (ph->p_type) { 2343 case PT_GNU_STACK: 2344 obj->stack_flags = ph->p_flags; 2345 break; 2346 case PT_GNU_RELRO: 2347 obj->relro_page = obj->relocbase + 2348 rtld_trunc_page(ph->p_vaddr); 2349 obj->relro_size = rtld_round_page(ph->p_memsz); 2350 break; 2351 case PT_NOTE: 2352 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 2353 note_end = note_start + ph->p_filesz; 2354 digest_notes(obj, note_start, note_end); 2355 break; 2356 } 2357 } 2358 } 2359 2360 /* 2361 * Initialize the dynamic linker. The argument is the address at which 2362 * the dynamic linker has been mapped into memory. The primary task of 2363 * this function is to relocate the dynamic linker. 2364 */ 2365 static void 2366 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 2367 { 2368 Obj_Entry objtmp; /* Temporary rtld object */ 2369 const Elf_Ehdr *ehdr; 2370 const Elf_Dyn *dyn_rpath; 2371 const Elf_Dyn *dyn_soname; 2372 const Elf_Dyn *dyn_runpath; 2373 2374 #ifdef RTLD_INIT_PAGESIZES_EARLY 2375 /* The page size is required by the dynamic memory allocator. */ 2376 init_pagesizes(aux_info); 2377 #endif 2378 2379 /* 2380 * Conjure up an Obj_Entry structure for the dynamic linker. 2381 * 2382 * The "path" member can't be initialized yet because string constants 2383 * cannot yet be accessed. Below we will set it correctly. 2384 */ 2385 memset(&objtmp, 0, sizeof(objtmp)); 2386 objtmp.path = NULL; 2387 objtmp.rtld = true; 2388 objtmp.mapbase = mapbase; 2389 #ifdef PIC 2390 objtmp.relocbase = mapbase; 2391 #endif 2392 2393 objtmp.dynamic = rtld_dynamic(&objtmp); 2394 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 2395 assert(objtmp.needed == NULL); 2396 assert(!objtmp.textrel); 2397 /* 2398 * Temporarily put the dynamic linker entry into the object list, so 2399 * that symbols can be found. 2400 */ 2401 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 2402 2403 ehdr = (Elf_Ehdr *)mapbase; 2404 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 2405 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 2406 2407 /* Initialize the object list. */ 2408 TAILQ_INIT(&obj_list); 2409 2410 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 2411 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 2412 2413 #ifndef RTLD_INIT_PAGESIZES_EARLY 2414 /* The page size is required by the dynamic memory allocator. */ 2415 init_pagesizes(aux_info); 2416 #endif 2417 2418 if (aux_info[AT_OSRELDATE] != NULL) 2419 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 2420 2421 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 2422 2423 /* Replace the path with a dynamically allocated copy. */ 2424 obj_rtld.path = xstrdup(ld_path_rtld); 2425 2426 parse_rtld_phdr(&obj_rtld); 2427 if (obj_enforce_relro(&obj_rtld) == -1) 2428 rtld_die(); 2429 2430 r_debug.r_version = R_DEBUG_VERSION; 2431 r_debug.r_brk = r_debug_state; 2432 r_debug.r_state = RT_CONSISTENT; 2433 r_debug.r_ldbase = obj_rtld.relocbase; 2434 } 2435 2436 /* 2437 * Retrieve the array of supported page sizes. The kernel provides the page 2438 * sizes in increasing order. 2439 */ 2440 static void 2441 init_pagesizes(Elf_Auxinfo **aux_info) 2442 { 2443 static size_t psa[MAXPAGESIZES]; 2444 int mib[2]; 2445 size_t len, size; 2446 2447 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 2448 NULL) { 2449 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 2450 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 2451 } else { 2452 len = 2; 2453 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 2454 size = sizeof(psa); 2455 else { 2456 /* As a fallback, retrieve the base page size. */ 2457 size = sizeof(psa[0]); 2458 if (aux_info[AT_PAGESZ] != NULL) { 2459 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 2460 goto psa_filled; 2461 } else { 2462 mib[0] = CTL_HW; 2463 mib[1] = HW_PAGESIZE; 2464 len = 2; 2465 } 2466 } 2467 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 2468 _rtld_error("sysctl for hw.pagesize(s) failed"); 2469 rtld_die(); 2470 } 2471 psa_filled: 2472 pagesizes = psa; 2473 } 2474 npagesizes = size / sizeof(pagesizes[0]); 2475 /* Discard any invalid entries at the end of the array. */ 2476 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 2477 npagesizes--; 2478 2479 page_size = pagesizes[0]; 2480 } 2481 2482 /* 2483 * Add the init functions from a needed object list (and its recursive 2484 * needed objects) to "list". This is not used directly; it is a helper 2485 * function for initlist_add_objects(). The write lock must be held 2486 * when this function is called. 2487 */ 2488 static void 2489 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 2490 { 2491 /* Recursively process the successor needed objects. */ 2492 if (needed->next != NULL) 2493 initlist_add_neededs(needed->next, list); 2494 2495 /* Process the current needed object. */ 2496 if (needed->obj != NULL) 2497 initlist_add_objects(needed->obj, needed->obj, list); 2498 } 2499 2500 /* 2501 * Scan all of the DAGs rooted in the range of objects from "obj" to 2502 * "tail" and add their init functions to "list". This recurses over 2503 * the DAGs and ensure the proper init ordering such that each object's 2504 * needed libraries are initialized before the object itself. At the 2505 * same time, this function adds the objects to the global finalization 2506 * list "list_fini" in the opposite order. The write lock must be 2507 * held when this function is called. 2508 */ 2509 static void 2510 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2511 { 2512 Obj_Entry *nobj; 2513 2514 if (obj->init_scanned || obj->init_done) 2515 return; 2516 obj->init_scanned = true; 2517 2518 /* Recursively process the successor objects. */ 2519 nobj = globallist_next(obj); 2520 if (nobj != NULL && obj != tail) 2521 initlist_add_objects(nobj, tail, list); 2522 2523 /* Recursively process the needed objects. */ 2524 if (obj->needed != NULL) 2525 initlist_add_neededs(obj->needed, list); 2526 if (obj->needed_filtees != NULL) 2527 initlist_add_neededs(obj->needed_filtees, list); 2528 if (obj->needed_aux_filtees != NULL) 2529 initlist_add_neededs(obj->needed_aux_filtees, list); 2530 2531 /* Add the object to the init list. */ 2532 objlist_push_tail(list, obj); 2533 2534 /* Add the object to the global fini list in the reverse order. */ 2535 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2536 && !obj->on_fini_list) { 2537 objlist_push_head(&list_fini, obj); 2538 obj->on_fini_list = true; 2539 } 2540 } 2541 2542 static void 2543 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate) 2544 { 2545 Needed_Entry *needed, *needed1; 2546 2547 for (needed = n; needed != NULL; needed = needed->next) { 2548 if (needed->obj != NULL) { 2549 dlclose_locked(needed->obj, lockstate); 2550 needed->obj = NULL; 2551 } 2552 } 2553 for (needed = n; needed != NULL; needed = needed1) { 2554 needed1 = needed->next; 2555 free(needed); 2556 } 2557 } 2558 2559 static void 2560 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate) 2561 { 2562 2563 free_needed_filtees(obj->needed_filtees, lockstate); 2564 obj->needed_filtees = NULL; 2565 free_needed_filtees(obj->needed_aux_filtees, lockstate); 2566 obj->needed_aux_filtees = NULL; 2567 obj->filtees_loaded = false; 2568 } 2569 2570 static void 2571 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2572 RtldLockState *lockstate) 2573 { 2574 2575 for (; needed != NULL; needed = needed->next) { 2576 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2577 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2578 RTLD_LOCAL, lockstate); 2579 } 2580 } 2581 2582 static void 2583 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2584 { 2585 2586 lock_restart_for_upgrade(lockstate); 2587 if (!obj->filtees_loaded) { 2588 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2589 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2590 obj->filtees_loaded = true; 2591 } 2592 } 2593 2594 static int 2595 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2596 { 2597 Obj_Entry *obj1; 2598 2599 for (; needed != NULL; needed = needed->next) { 2600 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2601 flags & ~RTLD_LO_NOLOAD); 2602 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2603 return (-1); 2604 } 2605 return (0); 2606 } 2607 2608 /* 2609 * Given a shared object, traverse its list of needed objects, and load 2610 * each of them. Returns 0 on success. Generates an error message and 2611 * returns -1 on failure. 2612 */ 2613 static int 2614 load_needed_objects(Obj_Entry *first, int flags) 2615 { 2616 Obj_Entry *obj; 2617 2618 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2619 if (obj->marker) 2620 continue; 2621 if (process_needed(obj, obj->needed, flags) == -1) 2622 return (-1); 2623 } 2624 return (0); 2625 } 2626 2627 static int 2628 load_preload_objects(const char *penv, bool isfd) 2629 { 2630 Obj_Entry *obj; 2631 const char *name; 2632 size_t len; 2633 char savech, *p, *psave; 2634 int fd; 2635 static const char delim[] = " \t:;"; 2636 2637 if (penv == NULL) 2638 return (0); 2639 2640 p = psave = xstrdup(penv); 2641 p += strspn(p, delim); 2642 while (*p != '\0') { 2643 len = strcspn(p, delim); 2644 2645 savech = p[len]; 2646 p[len] = '\0'; 2647 if (isfd) { 2648 name = NULL; 2649 fd = parse_integer(p); 2650 if (fd == -1) { 2651 free(psave); 2652 return (-1); 2653 } 2654 } else { 2655 name = p; 2656 fd = -1; 2657 } 2658 2659 obj = load_object(name, fd, NULL, 0); 2660 if (obj == NULL) { 2661 free(psave); 2662 return (-1); /* XXX - cleanup */ 2663 } 2664 obj->z_interpose = true; 2665 p[len] = savech; 2666 p += len; 2667 p += strspn(p, delim); 2668 } 2669 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2670 2671 free(psave); 2672 return (0); 2673 } 2674 2675 static const char * 2676 printable_path(const char *path) 2677 { 2678 2679 return (path == NULL ? "<unknown>" : path); 2680 } 2681 2682 /* 2683 * Load a shared object into memory, if it is not already loaded. The 2684 * object may be specified by name or by user-supplied file descriptor 2685 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2686 * duplicate is. 2687 * 2688 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2689 * on failure. 2690 */ 2691 static Obj_Entry * 2692 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2693 { 2694 Obj_Entry *obj; 2695 int fd; 2696 struct stat sb; 2697 char *path; 2698 2699 fd = -1; 2700 if (name != NULL) { 2701 TAILQ_FOREACH(obj, &obj_list, next) { 2702 if (obj->marker || obj->doomed) 2703 continue; 2704 if (object_match_name(obj, name)) 2705 return (obj); 2706 } 2707 2708 path = find_library(name, refobj, &fd); 2709 if (path == NULL) 2710 return (NULL); 2711 } else 2712 path = NULL; 2713 2714 if (fd >= 0) { 2715 /* 2716 * search_library_pathfds() opens a fresh file descriptor for the 2717 * library, so there is no need to dup(). 2718 */ 2719 } else if (fd_u == -1) { 2720 /* 2721 * If we didn't find a match by pathname, or the name is not 2722 * supplied, open the file and check again by device and inode. 2723 * This avoids false mismatches caused by multiple links or ".." 2724 * in pathnames. 2725 * 2726 * To avoid a race, we open the file and use fstat() rather than 2727 * using stat(). 2728 */ 2729 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { 2730 _rtld_error("Cannot open \"%s\"", path); 2731 free(path); 2732 return (NULL); 2733 } 2734 } else { 2735 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2736 if (fd == -1) { 2737 _rtld_error("Cannot dup fd"); 2738 free(path); 2739 return (NULL); 2740 } 2741 } 2742 if (fstat(fd, &sb) == -1) { 2743 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2744 close(fd); 2745 free(path); 2746 return (NULL); 2747 } 2748 TAILQ_FOREACH(obj, &obj_list, next) { 2749 if (obj->marker || obj->doomed) 2750 continue; 2751 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2752 break; 2753 } 2754 if (obj != NULL && name != NULL) { 2755 object_add_name(obj, name); 2756 free(path); 2757 close(fd); 2758 return (obj); 2759 } 2760 if (flags & RTLD_LO_NOLOAD) { 2761 free(path); 2762 close(fd); 2763 return (NULL); 2764 } 2765 2766 /* First use of this object, so we must map it in */ 2767 obj = do_load_object(fd, name, path, &sb, flags); 2768 if (obj == NULL) 2769 free(path); 2770 close(fd); 2771 2772 return (obj); 2773 } 2774 2775 static Obj_Entry * 2776 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2777 int flags) 2778 { 2779 Obj_Entry *obj; 2780 struct statfs fs; 2781 2782 /* 2783 * First, make sure that environment variables haven't been 2784 * used to circumvent the noexec flag on a filesystem. 2785 * We ignore fstatfs(2) failures, since fd might reference 2786 * not a file, e.g. shmfd. 2787 */ 2788 if (dangerous_ld_env && fstatfs(fd, &fs) == 0 && 2789 (fs.f_flags & MNT_NOEXEC) != 0) { 2790 _rtld_error("Cannot execute objects on %s", fs.f_mntonname); 2791 return (NULL); 2792 } 2793 2794 dbg("loading \"%s\"", printable_path(path)); 2795 obj = map_object(fd, printable_path(path), sbp); 2796 if (obj == NULL) 2797 return (NULL); 2798 2799 /* 2800 * If DT_SONAME is present in the object, digest_dynamic2 already 2801 * added it to the object names. 2802 */ 2803 if (name != NULL) 2804 object_add_name(obj, name); 2805 obj->path = path; 2806 if (!digest_dynamic(obj, 0)) 2807 goto errp; 2808 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2809 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2810 if (obj->z_pie && (flags & RTLD_LO_TRACE) == 0) { 2811 dbg("refusing to load PIE executable \"%s\"", obj->path); 2812 _rtld_error("Cannot load PIE binary %s as DSO", obj->path); 2813 goto errp; 2814 } 2815 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2816 RTLD_LO_DLOPEN) { 2817 dbg("refusing to load non-loadable \"%s\"", obj->path); 2818 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2819 goto errp; 2820 } 2821 2822 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2823 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2824 obj_count++; 2825 obj_loads++; 2826 linkmap_add(obj); /* for GDB & dlinfo() */ 2827 max_stack_flags |= obj->stack_flags; 2828 2829 dbg(" %p .. %p: %s", obj->mapbase, 2830 obj->mapbase + obj->mapsize - 1, obj->path); 2831 if (obj->textrel) 2832 dbg(" WARNING: %s has impure text", obj->path); 2833 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2834 obj->path); 2835 2836 return (obj); 2837 2838 errp: 2839 munmap(obj->mapbase, obj->mapsize); 2840 obj_free(obj); 2841 return (NULL); 2842 } 2843 2844 static int 2845 load_kpreload(const void *addr) 2846 { 2847 Obj_Entry *obj; 2848 const Elf_Ehdr *ehdr; 2849 const Elf_Phdr *phdr, *phlimit, *phdyn, *seg0, *segn; 2850 static const char kname[] = "[vdso]"; 2851 2852 ehdr = addr; 2853 if (!check_elf_headers(ehdr, "kpreload")) 2854 return (-1); 2855 obj = obj_new(); 2856 phdr = (const Elf_Phdr *)((const char *)addr + ehdr->e_phoff); 2857 obj->phdr = phdr; 2858 obj->phsize = ehdr->e_phnum * sizeof(*phdr); 2859 phlimit = phdr + ehdr->e_phnum; 2860 seg0 = segn = NULL; 2861 2862 for (; phdr < phlimit; phdr++) { 2863 switch (phdr->p_type) { 2864 case PT_DYNAMIC: 2865 phdyn = phdr; 2866 break; 2867 case PT_GNU_STACK: 2868 /* Absense of PT_GNU_STACK implies stack_flags == 0. */ 2869 obj->stack_flags = phdr->p_flags; 2870 break; 2871 case PT_LOAD: 2872 if (seg0 == NULL || seg0->p_vaddr > phdr->p_vaddr) 2873 seg0 = phdr; 2874 if (segn == NULL || segn->p_vaddr + segn->p_memsz < 2875 phdr->p_vaddr + phdr->p_memsz) 2876 segn = phdr; 2877 break; 2878 } 2879 } 2880 2881 obj->mapbase = __DECONST(caddr_t, addr); 2882 obj->mapsize = segn->p_vaddr + segn->p_memsz - (Elf_Addr)addr; 2883 obj->vaddrbase = 0; 2884 obj->relocbase = obj->mapbase; 2885 2886 object_add_name(obj, kname); 2887 obj->path = xstrdup(kname); 2888 obj->dynamic = (const Elf_Dyn *)(obj->relocbase + phdyn->p_vaddr); 2889 2890 if (!digest_dynamic(obj, 0)) { 2891 obj_free(obj); 2892 return (-1); 2893 } 2894 2895 /* 2896 * We assume that kernel-preloaded object does not need 2897 * relocation. It is currently written into read-only page, 2898 * handling relocations would mean we need to allocate at 2899 * least one additional page per AS. 2900 */ 2901 dbg("%s mapbase %p phdrs %p PT_LOAD phdr %p vaddr %p dynamic %p", 2902 obj->path, obj->mapbase, obj->phdr, seg0, 2903 obj->relocbase + seg0->p_vaddr, obj->dynamic); 2904 2905 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2906 obj_count++; 2907 obj_loads++; 2908 linkmap_add(obj); /* for GDB & dlinfo() */ 2909 max_stack_flags |= obj->stack_flags; 2910 2911 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, 0, 0, obj->path); 2912 return (0); 2913 } 2914 2915 Obj_Entry * 2916 obj_from_addr(const void *addr) 2917 { 2918 Obj_Entry *obj; 2919 2920 TAILQ_FOREACH(obj, &obj_list, next) { 2921 if (obj->marker) 2922 continue; 2923 if (addr < (void *) obj->mapbase) 2924 continue; 2925 if (addr < (void *)(obj->mapbase + obj->mapsize)) 2926 return obj; 2927 } 2928 return (NULL); 2929 } 2930 2931 static void 2932 preinit_main(void) 2933 { 2934 Elf_Addr *preinit_addr; 2935 int index; 2936 2937 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2938 if (preinit_addr == NULL) 2939 return; 2940 2941 for (index = 0; index < obj_main->preinit_array_num; index++) { 2942 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2943 dbg("calling preinit function for %s at %p", obj_main->path, 2944 (void *)preinit_addr[index]); 2945 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2946 0, 0, obj_main->path); 2947 call_init_pointer(obj_main, preinit_addr[index]); 2948 } 2949 } 2950 } 2951 2952 /* 2953 * Call the finalization functions for each of the objects in "list" 2954 * belonging to the DAG of "root" and referenced once. If NULL "root" 2955 * is specified, every finalization function will be called regardless 2956 * of the reference count and the list elements won't be freed. All of 2957 * the objects are expected to have non-NULL fini functions. 2958 */ 2959 static void 2960 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2961 { 2962 Objlist_Entry *elm; 2963 struct dlerror_save *saved_msg; 2964 Elf_Addr *fini_addr; 2965 int index; 2966 2967 assert(root == NULL || root->refcount == 1); 2968 2969 if (root != NULL) 2970 root->doomed = true; 2971 2972 /* 2973 * Preserve the current error message since a fini function might 2974 * call into the dynamic linker and overwrite it. 2975 */ 2976 saved_msg = errmsg_save(); 2977 do { 2978 STAILQ_FOREACH(elm, list, link) { 2979 if (root != NULL && (elm->obj->refcount != 1 || 2980 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2981 continue; 2982 /* Remove object from fini list to prevent recursive invocation. */ 2983 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2984 /* Ensure that new references cannot be acquired. */ 2985 elm->obj->doomed = true; 2986 2987 hold_object(elm->obj); 2988 lock_release(rtld_bind_lock, lockstate); 2989 /* 2990 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2991 * When this happens, DT_FINI_ARRAY is processed first. 2992 */ 2993 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2994 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2995 for (index = elm->obj->fini_array_num - 1; index >= 0; 2996 index--) { 2997 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2998 dbg("calling fini function for %s at %p", 2999 elm->obj->path, (void *)fini_addr[index]); 3000 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 3001 (void *)fini_addr[index], 0, 0, elm->obj->path); 3002 call_initfini_pointer(elm->obj, fini_addr[index]); 3003 } 3004 } 3005 } 3006 if (elm->obj->fini != (Elf_Addr)NULL) { 3007 dbg("calling fini function for %s at %p", elm->obj->path, 3008 (void *)elm->obj->fini); 3009 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 3010 0, 0, elm->obj->path); 3011 call_initfini_pointer(elm->obj, elm->obj->fini); 3012 } 3013 wlock_acquire(rtld_bind_lock, lockstate); 3014 unhold_object(elm->obj); 3015 /* No need to free anything if process is going down. */ 3016 if (root != NULL) 3017 free(elm); 3018 /* 3019 * We must restart the list traversal after every fini call 3020 * because a dlclose() call from the fini function or from 3021 * another thread might have modified the reference counts. 3022 */ 3023 break; 3024 } 3025 } while (elm != NULL); 3026 errmsg_restore(saved_msg); 3027 } 3028 3029 /* 3030 * Call the initialization functions for each of the objects in 3031 * "list". All of the objects are expected to have non-NULL init 3032 * functions. 3033 */ 3034 static void 3035 objlist_call_init(Objlist *list, RtldLockState *lockstate) 3036 { 3037 Objlist_Entry *elm; 3038 Obj_Entry *obj; 3039 struct dlerror_save *saved_msg; 3040 Elf_Addr *init_addr; 3041 void (*reg)(void (*)(void)); 3042 int index; 3043 3044 /* 3045 * Clean init_scanned flag so that objects can be rechecked and 3046 * possibly initialized earlier if any of vectors called below 3047 * cause the change by using dlopen. 3048 */ 3049 TAILQ_FOREACH(obj, &obj_list, next) { 3050 if (obj->marker) 3051 continue; 3052 obj->init_scanned = false; 3053 } 3054 3055 /* 3056 * Preserve the current error message since an init function might 3057 * call into the dynamic linker and overwrite it. 3058 */ 3059 saved_msg = errmsg_save(); 3060 STAILQ_FOREACH(elm, list, link) { 3061 if (elm->obj->init_done) /* Initialized early. */ 3062 continue; 3063 /* 3064 * Race: other thread might try to use this object before current 3065 * one completes the initialization. Not much can be done here 3066 * without better locking. 3067 */ 3068 elm->obj->init_done = true; 3069 hold_object(elm->obj); 3070 reg = NULL; 3071 if (elm->obj == obj_main && obj_main->crt_no_init) { 3072 reg = (void (*)(void (*)(void)))get_program_var_addr( 3073 "__libc_atexit", lockstate); 3074 } 3075 lock_release(rtld_bind_lock, lockstate); 3076 if (reg != NULL) { 3077 reg(rtld_exit); 3078 rtld_exit_ptr = rtld_nop_exit; 3079 } 3080 3081 /* 3082 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 3083 * When this happens, DT_INIT is processed first. 3084 */ 3085 if (elm->obj->init != (Elf_Addr)NULL) { 3086 dbg("calling init function for %s at %p", elm->obj->path, 3087 (void *)elm->obj->init); 3088 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 3089 0, 0, elm->obj->path); 3090 call_init_pointer(elm->obj, elm->obj->init); 3091 } 3092 init_addr = (Elf_Addr *)elm->obj->init_array; 3093 if (init_addr != NULL) { 3094 for (index = 0; index < elm->obj->init_array_num; index++) { 3095 if (init_addr[index] != 0 && init_addr[index] != 1) { 3096 dbg("calling init function for %s at %p", elm->obj->path, 3097 (void *)init_addr[index]); 3098 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 3099 (void *)init_addr[index], 0, 0, elm->obj->path); 3100 call_init_pointer(elm->obj, init_addr[index]); 3101 } 3102 } 3103 } 3104 wlock_acquire(rtld_bind_lock, lockstate); 3105 unhold_object(elm->obj); 3106 } 3107 errmsg_restore(saved_msg); 3108 } 3109 3110 static void 3111 objlist_clear(Objlist *list) 3112 { 3113 Objlist_Entry *elm; 3114 3115 while (!STAILQ_EMPTY(list)) { 3116 elm = STAILQ_FIRST(list); 3117 STAILQ_REMOVE_HEAD(list, link); 3118 free(elm); 3119 } 3120 } 3121 3122 static Objlist_Entry * 3123 objlist_find(Objlist *list, const Obj_Entry *obj) 3124 { 3125 Objlist_Entry *elm; 3126 3127 STAILQ_FOREACH(elm, list, link) 3128 if (elm->obj == obj) 3129 return elm; 3130 return (NULL); 3131 } 3132 3133 static void 3134 objlist_init(Objlist *list) 3135 { 3136 STAILQ_INIT(list); 3137 } 3138 3139 static void 3140 objlist_push_head(Objlist *list, Obj_Entry *obj) 3141 { 3142 Objlist_Entry *elm; 3143 3144 elm = NEW(Objlist_Entry); 3145 elm->obj = obj; 3146 STAILQ_INSERT_HEAD(list, elm, link); 3147 } 3148 3149 static void 3150 objlist_push_tail(Objlist *list, Obj_Entry *obj) 3151 { 3152 Objlist_Entry *elm; 3153 3154 elm = NEW(Objlist_Entry); 3155 elm->obj = obj; 3156 STAILQ_INSERT_TAIL(list, elm, link); 3157 } 3158 3159 static void 3160 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 3161 { 3162 Objlist_Entry *elm, *listelm; 3163 3164 STAILQ_FOREACH(listelm, list, link) { 3165 if (listelm->obj == listobj) 3166 break; 3167 } 3168 elm = NEW(Objlist_Entry); 3169 elm->obj = obj; 3170 if (listelm != NULL) 3171 STAILQ_INSERT_AFTER(list, listelm, elm, link); 3172 else 3173 STAILQ_INSERT_TAIL(list, elm, link); 3174 } 3175 3176 static void 3177 objlist_remove(Objlist *list, Obj_Entry *obj) 3178 { 3179 Objlist_Entry *elm; 3180 3181 if ((elm = objlist_find(list, obj)) != NULL) { 3182 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 3183 free(elm); 3184 } 3185 } 3186 3187 /* 3188 * Relocate dag rooted in the specified object. 3189 * Returns 0 on success, or -1 on failure. 3190 */ 3191 3192 static int 3193 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 3194 int flags, RtldLockState *lockstate) 3195 { 3196 Objlist_Entry *elm; 3197 int error; 3198 3199 error = 0; 3200 STAILQ_FOREACH(elm, &root->dagmembers, link) { 3201 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 3202 lockstate); 3203 if (error == -1) 3204 break; 3205 } 3206 return (error); 3207 } 3208 3209 /* 3210 * Prepare for, or clean after, relocating an object marked with 3211 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 3212 * segments are remapped read-write. After relocations are done, the 3213 * segment's permissions are returned back to the modes specified in 3214 * the phdrs. If any relocation happened, or always for wired 3215 * program, COW is triggered. 3216 */ 3217 static int 3218 reloc_textrel_prot(Obj_Entry *obj, bool before) 3219 { 3220 const Elf_Phdr *ph; 3221 void *base; 3222 size_t l, sz; 3223 int prot; 3224 3225 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 3226 l--, ph++) { 3227 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 3228 continue; 3229 base = obj->relocbase + rtld_trunc_page(ph->p_vaddr); 3230 sz = rtld_round_page(ph->p_vaddr + ph->p_filesz) - 3231 rtld_trunc_page(ph->p_vaddr); 3232 prot = before ? (PROT_READ | PROT_WRITE) : 3233 convert_prot(ph->p_flags); 3234 if (mprotect(base, sz, prot) == -1) { 3235 _rtld_error("%s: Cannot write-%sable text segment: %s", 3236 obj->path, before ? "en" : "dis", 3237 rtld_strerror(errno)); 3238 return (-1); 3239 } 3240 } 3241 return (0); 3242 } 3243 3244 /* Process RELR relative relocations. */ 3245 static void 3246 reloc_relr(Obj_Entry *obj) 3247 { 3248 const Elf_Relr *relr, *relrlim; 3249 Elf_Addr *where; 3250 3251 relrlim = (const Elf_Relr *)((const char *)obj->relr + obj->relrsize); 3252 for (relr = obj->relr; relr < relrlim; relr++) { 3253 Elf_Relr entry = *relr; 3254 3255 if ((entry & 1) == 0) { 3256 where = (Elf_Addr *)(obj->relocbase + entry); 3257 *where++ += (Elf_Addr)obj->relocbase; 3258 } else { 3259 for (long i = 0; (entry >>= 1) != 0; i++) 3260 if ((entry & 1) != 0) 3261 where[i] += (Elf_Addr)obj->relocbase; 3262 where += CHAR_BIT * sizeof(Elf_Relr) - 1; 3263 } 3264 } 3265 } 3266 3267 /* 3268 * Relocate single object. 3269 * Returns 0 on success, or -1 on failure. 3270 */ 3271 static int 3272 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 3273 int flags, RtldLockState *lockstate) 3274 { 3275 3276 if (obj->relocated) 3277 return (0); 3278 obj->relocated = true; 3279 if (obj != rtldobj) 3280 dbg("relocating \"%s\"", obj->path); 3281 3282 if (obj->symtab == NULL || obj->strtab == NULL || 3283 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) 3284 dbg("object %s has no run-time symbol table", obj->path); 3285 3286 /* There are relocations to the write-protected text segment. */ 3287 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 3288 return (-1); 3289 3290 /* Process the non-PLT non-IFUNC relocations. */ 3291 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 3292 return (-1); 3293 reloc_relr(obj); 3294 3295 /* Re-protected the text segment. */ 3296 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 3297 return (-1); 3298 3299 /* Set the special PLT or GOT entries. */ 3300 init_pltgot(obj); 3301 3302 /* Process the PLT relocations. */ 3303 if (reloc_plt(obj, flags, lockstate) == -1) 3304 return (-1); 3305 /* Relocate the jump slots if we are doing immediate binding. */ 3306 if ((obj->bind_now || bind_now) && reloc_jmpslots(obj, flags, 3307 lockstate) == -1) 3308 return (-1); 3309 3310 if (!obj->mainprog && obj_enforce_relro(obj) == -1) 3311 return (-1); 3312 3313 /* 3314 * Set up the magic number and version in the Obj_Entry. These 3315 * were checked in the crt1.o from the original ElfKit, so we 3316 * set them for backward compatibility. 3317 */ 3318 obj->magic = RTLD_MAGIC; 3319 obj->version = RTLD_VERSION; 3320 3321 return (0); 3322 } 3323 3324 /* 3325 * Relocate newly-loaded shared objects. The argument is a pointer to 3326 * the Obj_Entry for the first such object. All objects from the first 3327 * to the end of the list of objects are relocated. Returns 0 on success, 3328 * or -1 on failure. 3329 */ 3330 static int 3331 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 3332 int flags, RtldLockState *lockstate) 3333 { 3334 Obj_Entry *obj; 3335 int error; 3336 3337 for (error = 0, obj = first; obj != NULL; 3338 obj = TAILQ_NEXT(obj, next)) { 3339 if (obj->marker) 3340 continue; 3341 error = relocate_object(obj, bind_now, rtldobj, flags, 3342 lockstate); 3343 if (error == -1) 3344 break; 3345 } 3346 return (error); 3347 } 3348 3349 /* 3350 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 3351 * referencing STT_GNU_IFUNC symbols is postponed till the other 3352 * relocations are done. The indirect functions specified as 3353 * ifunc are allowed to call other symbols, so we need to have 3354 * objects relocated before asking for resolution from indirects. 3355 * 3356 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 3357 * instead of the usual lazy handling of PLT slots. It is 3358 * consistent with how GNU does it. 3359 */ 3360 static int 3361 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 3362 RtldLockState *lockstate) 3363 { 3364 3365 if (obj->ifuncs_resolved) 3366 return (0); 3367 obj->ifuncs_resolved = true; 3368 if (!obj->irelative && !obj->irelative_nonplt && 3369 !((obj->bind_now || bind_now) && obj->gnu_ifunc) && 3370 !obj->non_plt_gnu_ifunc) 3371 return (0); 3372 if (obj_disable_relro(obj) == -1 || 3373 (obj->irelative && reloc_iresolve(obj, lockstate) == -1) || 3374 (obj->irelative_nonplt && reloc_iresolve_nonplt(obj, 3375 lockstate) == -1) || 3376 ((obj->bind_now || bind_now) && obj->gnu_ifunc && 3377 reloc_gnu_ifunc(obj, flags, lockstate) == -1) || 3378 (obj->non_plt_gnu_ifunc && reloc_non_plt(obj, &obj_rtld, 3379 flags | SYMLOOK_IFUNC, lockstate) == -1) || 3380 obj_enforce_relro(obj) == -1) 3381 return (-1); 3382 return (0); 3383 } 3384 3385 static int 3386 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 3387 RtldLockState *lockstate) 3388 { 3389 Objlist_Entry *elm; 3390 Obj_Entry *obj; 3391 3392 STAILQ_FOREACH(elm, list, link) { 3393 obj = elm->obj; 3394 if (obj->marker) 3395 continue; 3396 if (resolve_object_ifunc(obj, bind_now, flags, 3397 lockstate) == -1) 3398 return (-1); 3399 } 3400 return (0); 3401 } 3402 3403 /* 3404 * Cleanup procedure. It will be called (by the atexit mechanism) just 3405 * before the process exits. 3406 */ 3407 static void 3408 rtld_exit(void) 3409 { 3410 RtldLockState lockstate; 3411 3412 wlock_acquire(rtld_bind_lock, &lockstate); 3413 dbg("rtld_exit()"); 3414 objlist_call_fini(&list_fini, NULL, &lockstate); 3415 /* No need to remove the items from the list, since we are exiting. */ 3416 if (!libmap_disable) 3417 lm_fini(); 3418 lock_release(rtld_bind_lock, &lockstate); 3419 } 3420 3421 static void 3422 rtld_nop_exit(void) 3423 { 3424 } 3425 3426 /* 3427 * Iterate over a search path, translate each element, and invoke the 3428 * callback on the result. 3429 */ 3430 static void * 3431 path_enumerate(const char *path, path_enum_proc callback, 3432 const char *refobj_path, void *arg) 3433 { 3434 const char *trans; 3435 if (path == NULL) 3436 return (NULL); 3437 3438 path += strspn(path, ":;"); 3439 while (*path != '\0') { 3440 size_t len; 3441 char *res; 3442 3443 len = strcspn(path, ":;"); 3444 trans = lm_findn(refobj_path, path, len); 3445 if (trans) 3446 res = callback(trans, strlen(trans), arg); 3447 else 3448 res = callback(path, len, arg); 3449 3450 if (res != NULL) 3451 return (res); 3452 3453 path += len; 3454 path += strspn(path, ":;"); 3455 } 3456 3457 return (NULL); 3458 } 3459 3460 struct try_library_args { 3461 const char *name; 3462 size_t namelen; 3463 char *buffer; 3464 size_t buflen; 3465 int fd; 3466 }; 3467 3468 static void * 3469 try_library_path(const char *dir, size_t dirlen, void *param) 3470 { 3471 struct try_library_args *arg; 3472 int fd; 3473 3474 arg = param; 3475 if (*dir == '/' || trust) { 3476 char *pathname; 3477 3478 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 3479 return (NULL); 3480 3481 pathname = arg->buffer; 3482 strncpy(pathname, dir, dirlen); 3483 pathname[dirlen] = '/'; 3484 strcpy(pathname + dirlen + 1, arg->name); 3485 3486 dbg(" Trying \"%s\"", pathname); 3487 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY); 3488 if (fd >= 0) { 3489 dbg(" Opened \"%s\", fd %d", pathname, fd); 3490 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 3491 strcpy(pathname, arg->buffer); 3492 arg->fd = fd; 3493 return (pathname); 3494 } else { 3495 dbg(" Failed to open \"%s\": %s", 3496 pathname, rtld_strerror(errno)); 3497 } 3498 } 3499 return (NULL); 3500 } 3501 3502 static char * 3503 search_library_path(const char *name, const char *path, 3504 const char *refobj_path, int *fdp) 3505 { 3506 char *p; 3507 struct try_library_args arg; 3508 3509 if (path == NULL) 3510 return (NULL); 3511 3512 arg.name = name; 3513 arg.namelen = strlen(name); 3514 arg.buffer = xmalloc(PATH_MAX); 3515 arg.buflen = PATH_MAX; 3516 arg.fd = -1; 3517 3518 p = path_enumerate(path, try_library_path, refobj_path, &arg); 3519 *fdp = arg.fd; 3520 3521 free(arg.buffer); 3522 3523 return (p); 3524 } 3525 3526 3527 /* 3528 * Finds the library with the given name using the directory descriptors 3529 * listed in the LD_LIBRARY_PATH_FDS environment variable. 3530 * 3531 * Returns a freshly-opened close-on-exec file descriptor for the library, 3532 * or -1 if the library cannot be found. 3533 */ 3534 static char * 3535 search_library_pathfds(const char *name, const char *path, int *fdp) 3536 { 3537 char *envcopy, *fdstr, *found, *last_token; 3538 size_t len; 3539 int dirfd, fd; 3540 3541 dbg("%s('%s', '%s', fdp)", __func__, name, path); 3542 3543 /* Don't load from user-specified libdirs into setuid binaries. */ 3544 if (!trust) 3545 return (NULL); 3546 3547 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 3548 if (path == NULL) 3549 return (NULL); 3550 3551 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 3552 if (name[0] == '/') { 3553 dbg("Absolute path (%s) passed to %s", name, __func__); 3554 return (NULL); 3555 } 3556 3557 /* 3558 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 3559 * copy of the path, as strtok_r rewrites separator tokens 3560 * with '\0'. 3561 */ 3562 found = NULL; 3563 envcopy = xstrdup(path); 3564 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 3565 fdstr = strtok_r(NULL, ":", &last_token)) { 3566 dirfd = parse_integer(fdstr); 3567 if (dirfd < 0) { 3568 _rtld_error("failed to parse directory FD: '%s'", 3569 fdstr); 3570 break; 3571 } 3572 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 3573 if (fd >= 0) { 3574 *fdp = fd; 3575 len = strlen(fdstr) + strlen(name) + 3; 3576 found = xmalloc(len); 3577 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 3578 _rtld_error("error generating '%d/%s'", 3579 dirfd, name); 3580 rtld_die(); 3581 } 3582 dbg("open('%s') => %d", found, fd); 3583 break; 3584 } 3585 } 3586 free(envcopy); 3587 3588 return (found); 3589 } 3590 3591 3592 int 3593 dlclose(void *handle) 3594 { 3595 RtldLockState lockstate; 3596 int error; 3597 3598 wlock_acquire(rtld_bind_lock, &lockstate); 3599 error = dlclose_locked(handle, &lockstate); 3600 lock_release(rtld_bind_lock, &lockstate); 3601 return (error); 3602 } 3603 3604 static int 3605 dlclose_locked(void *handle, RtldLockState *lockstate) 3606 { 3607 Obj_Entry *root; 3608 3609 root = dlcheck(handle); 3610 if (root == NULL) 3611 return (-1); 3612 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 3613 root->path); 3614 3615 /* Unreference the object and its dependencies. */ 3616 root->dl_refcount--; 3617 3618 if (root->refcount == 1) { 3619 /* 3620 * The object will be no longer referenced, so we must unload it. 3621 * First, call the fini functions. 3622 */ 3623 objlist_call_fini(&list_fini, root, lockstate); 3624 3625 unref_dag(root); 3626 3627 /* Finish cleaning up the newly-unreferenced objects. */ 3628 GDB_STATE(RT_DELETE,&root->linkmap); 3629 unload_object(root, lockstate); 3630 GDB_STATE(RT_CONSISTENT,NULL); 3631 } else 3632 unref_dag(root); 3633 3634 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 3635 return (0); 3636 } 3637 3638 char * 3639 dlerror(void) 3640 { 3641 if (*(lockinfo.dlerror_seen()) != 0) 3642 return (NULL); 3643 *lockinfo.dlerror_seen() = 1; 3644 return (lockinfo.dlerror_loc()); 3645 } 3646 3647 /* 3648 * This function is deprecated and has no effect. 3649 */ 3650 void 3651 dllockinit(void *context, 3652 void *(*_lock_create)(void *context) __unused, 3653 void (*_rlock_acquire)(void *lock) __unused, 3654 void (*_wlock_acquire)(void *lock) __unused, 3655 void (*_lock_release)(void *lock) __unused, 3656 void (*_lock_destroy)(void *lock) __unused, 3657 void (*context_destroy)(void *context)) 3658 { 3659 static void *cur_context; 3660 static void (*cur_context_destroy)(void *); 3661 3662 /* Just destroy the context from the previous call, if necessary. */ 3663 if (cur_context_destroy != NULL) 3664 cur_context_destroy(cur_context); 3665 cur_context = context; 3666 cur_context_destroy = context_destroy; 3667 } 3668 3669 void * 3670 dlopen(const char *name, int mode) 3671 { 3672 3673 return (rtld_dlopen(name, -1, mode)); 3674 } 3675 3676 void * 3677 fdlopen(int fd, int mode) 3678 { 3679 3680 return (rtld_dlopen(NULL, fd, mode)); 3681 } 3682 3683 static void * 3684 rtld_dlopen(const char *name, int fd, int mode) 3685 { 3686 RtldLockState lockstate; 3687 int lo_flags; 3688 3689 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3690 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3691 if (ld_tracing != NULL) { 3692 rlock_acquire(rtld_bind_lock, &lockstate); 3693 if (sigsetjmp(lockstate.env, 0) != 0) 3694 lock_upgrade(rtld_bind_lock, &lockstate); 3695 environ = __DECONST(char **, *get_program_var_addr("environ", &lockstate)); 3696 lock_release(rtld_bind_lock, &lockstate); 3697 } 3698 lo_flags = RTLD_LO_DLOPEN; 3699 if (mode & RTLD_NODELETE) 3700 lo_flags |= RTLD_LO_NODELETE; 3701 if (mode & RTLD_NOLOAD) 3702 lo_flags |= RTLD_LO_NOLOAD; 3703 if (mode & RTLD_DEEPBIND) 3704 lo_flags |= RTLD_LO_DEEPBIND; 3705 if (ld_tracing != NULL) 3706 lo_flags |= RTLD_LO_TRACE | RTLD_LO_IGNSTLS; 3707 3708 return (dlopen_object(name, fd, obj_main, lo_flags, 3709 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3710 } 3711 3712 static void 3713 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate) 3714 { 3715 3716 obj->dl_refcount--; 3717 unref_dag(obj); 3718 if (obj->refcount == 0) 3719 unload_object(obj, lockstate); 3720 } 3721 3722 static Obj_Entry * 3723 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3724 int mode, RtldLockState *lockstate) 3725 { 3726 Obj_Entry *obj; 3727 Objlist initlist; 3728 RtldLockState mlockstate; 3729 int result; 3730 3731 dbg("dlopen_object name \"%s\" fd %d refobj \"%s\" lo_flags %#x mode %#x", 3732 name != NULL ? name : "<null>", fd, refobj == NULL ? "<null>" : 3733 refobj->path, lo_flags, mode); 3734 objlist_init(&initlist); 3735 3736 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3737 wlock_acquire(rtld_bind_lock, &mlockstate); 3738 lockstate = &mlockstate; 3739 } 3740 GDB_STATE(RT_ADD,NULL); 3741 3742 obj = NULL; 3743 if (name == NULL && fd == -1) { 3744 obj = obj_main; 3745 obj->refcount++; 3746 } else { 3747 obj = load_object(name, fd, refobj, lo_flags); 3748 } 3749 3750 if (obj) { 3751 obj->dl_refcount++; 3752 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3753 objlist_push_tail(&list_global, obj); 3754 3755 if (!obj->init_done) { 3756 /* We loaded something new and have to init something. */ 3757 if ((lo_flags & RTLD_LO_DEEPBIND) != 0) 3758 obj->deepbind = true; 3759 result = 0; 3760 if ((lo_flags & (RTLD_LO_EARLY | RTLD_LO_IGNSTLS)) == 0 && 3761 obj->static_tls && !allocate_tls_offset(obj)) { 3762 _rtld_error("%s: No space available " 3763 "for static Thread Local Storage", obj->path); 3764 result = -1; 3765 } 3766 if (result != -1) 3767 result = load_needed_objects(obj, lo_flags & (RTLD_LO_DLOPEN | 3768 RTLD_LO_EARLY | RTLD_LO_IGNSTLS | RTLD_LO_TRACE)); 3769 init_dag(obj); 3770 ref_dag(obj); 3771 if (result != -1) 3772 result = rtld_verify_versions(&obj->dagmembers); 3773 if (result != -1 && ld_tracing) 3774 goto trace; 3775 if (result == -1 || relocate_object_dag(obj, 3776 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3777 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3778 lockstate) == -1) { 3779 dlopen_cleanup(obj, lockstate); 3780 obj = NULL; 3781 } else if (lo_flags & RTLD_LO_EARLY) { 3782 /* 3783 * Do not call the init functions for early loaded 3784 * filtees. The image is still not initialized enough 3785 * for them to work. 3786 * 3787 * Our object is found by the global object list and 3788 * will be ordered among all init calls done right 3789 * before transferring control to main. 3790 */ 3791 } else { 3792 /* Make list of init functions to call. */ 3793 initlist_add_objects(obj, obj, &initlist); 3794 } 3795 /* 3796 * Process all no_delete or global objects here, given 3797 * them own DAGs to prevent their dependencies from being 3798 * unloaded. This has to be done after we have loaded all 3799 * of the dependencies, so that we do not miss any. 3800 */ 3801 if (obj != NULL) 3802 process_z(obj); 3803 } else { 3804 /* 3805 * Bump the reference counts for objects on this DAG. If 3806 * this is the first dlopen() call for the object that was 3807 * already loaded as a dependency, initialize the dag 3808 * starting at it. 3809 */ 3810 init_dag(obj); 3811 ref_dag(obj); 3812 3813 if ((lo_flags & RTLD_LO_TRACE) != 0) 3814 goto trace; 3815 } 3816 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3817 obj->z_nodelete) && !obj->ref_nodel) { 3818 dbg("obj %s nodelete", obj->path); 3819 ref_dag(obj); 3820 obj->z_nodelete = obj->ref_nodel = true; 3821 } 3822 } 3823 3824 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3825 name); 3826 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3827 3828 if ((lo_flags & RTLD_LO_EARLY) == 0) { 3829 map_stacks_exec(lockstate); 3830 if (obj != NULL) 3831 distribute_static_tls(&initlist, lockstate); 3832 } 3833 3834 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3835 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3836 lockstate) == -1) { 3837 objlist_clear(&initlist); 3838 dlopen_cleanup(obj, lockstate); 3839 if (lockstate == &mlockstate) 3840 lock_release(rtld_bind_lock, lockstate); 3841 return (NULL); 3842 } 3843 3844 if (!(lo_flags & RTLD_LO_EARLY)) { 3845 /* Call the init functions. */ 3846 objlist_call_init(&initlist, lockstate); 3847 } 3848 objlist_clear(&initlist); 3849 if (lockstate == &mlockstate) 3850 lock_release(rtld_bind_lock, lockstate); 3851 return (obj); 3852 trace: 3853 trace_loaded_objects(obj, false); 3854 if (lockstate == &mlockstate) 3855 lock_release(rtld_bind_lock, lockstate); 3856 exit(0); 3857 } 3858 3859 static void * 3860 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3861 int flags) 3862 { 3863 DoneList donelist; 3864 const Obj_Entry *obj, *defobj; 3865 const Elf_Sym *def; 3866 SymLook req; 3867 RtldLockState lockstate; 3868 tls_index ti; 3869 void *sym; 3870 int res; 3871 3872 def = NULL; 3873 defobj = NULL; 3874 symlook_init(&req, name); 3875 req.ventry = ve; 3876 req.flags = flags | SYMLOOK_IN_PLT; 3877 req.lockstate = &lockstate; 3878 3879 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3880 rlock_acquire(rtld_bind_lock, &lockstate); 3881 if (sigsetjmp(lockstate.env, 0) != 0) 3882 lock_upgrade(rtld_bind_lock, &lockstate); 3883 if (handle == NULL || handle == RTLD_NEXT || 3884 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3885 3886 if ((obj = obj_from_addr(retaddr)) == NULL) { 3887 _rtld_error("Cannot determine caller's shared object"); 3888 lock_release(rtld_bind_lock, &lockstate); 3889 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3890 return (NULL); 3891 } 3892 if (handle == NULL) { /* Just the caller's shared object. */ 3893 res = symlook_obj(&req, obj); 3894 if (res == 0) { 3895 def = req.sym_out; 3896 defobj = req.defobj_out; 3897 } 3898 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3899 handle == RTLD_SELF) { /* ... caller included */ 3900 if (handle == RTLD_NEXT) 3901 obj = globallist_next(obj); 3902 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3903 if (obj->marker) 3904 continue; 3905 res = symlook_obj(&req, obj); 3906 if (res == 0) { 3907 if (def == NULL || (ld_dynamic_weak && 3908 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK)) { 3909 def = req.sym_out; 3910 defobj = req.defobj_out; 3911 if (!ld_dynamic_weak || 3912 ELF_ST_BIND(def->st_info) != STB_WEAK) 3913 break; 3914 } 3915 } 3916 } 3917 /* 3918 * Search the dynamic linker itself, and possibly resolve the 3919 * symbol from there. This is how the application links to 3920 * dynamic linker services such as dlopen. 3921 * Note that we ignore ld_dynamic_weak == false case, 3922 * always overriding weak symbols by rtld definitions. 3923 */ 3924 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3925 res = symlook_obj(&req, &obj_rtld); 3926 if (res == 0) { 3927 def = req.sym_out; 3928 defobj = req.defobj_out; 3929 } 3930 } 3931 } else { 3932 assert(handle == RTLD_DEFAULT); 3933 res = symlook_default(&req, obj); 3934 if (res == 0) { 3935 defobj = req.defobj_out; 3936 def = req.sym_out; 3937 } 3938 } 3939 } else { 3940 if ((obj = dlcheck(handle)) == NULL) { 3941 lock_release(rtld_bind_lock, &lockstate); 3942 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3943 return (NULL); 3944 } 3945 3946 donelist_init(&donelist); 3947 if (obj->mainprog) { 3948 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3949 res = symlook_global(&req, &donelist); 3950 if (res == 0) { 3951 def = req.sym_out; 3952 defobj = req.defobj_out; 3953 } 3954 /* 3955 * Search the dynamic linker itself, and possibly resolve the 3956 * symbol from there. This is how the application links to 3957 * dynamic linker services such as dlopen. 3958 */ 3959 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3960 res = symlook_obj(&req, &obj_rtld); 3961 if (res == 0) { 3962 def = req.sym_out; 3963 defobj = req.defobj_out; 3964 } 3965 } 3966 } 3967 else { 3968 /* Search the whole DAG rooted at the given object. */ 3969 res = symlook_list(&req, &obj->dagmembers, &donelist); 3970 if (res == 0) { 3971 def = req.sym_out; 3972 defobj = req.defobj_out; 3973 } 3974 } 3975 } 3976 3977 if (def != NULL) { 3978 lock_release(rtld_bind_lock, &lockstate); 3979 3980 /* 3981 * The value required by the caller is derived from the value 3982 * of the symbol. this is simply the relocated value of the 3983 * symbol. 3984 */ 3985 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3986 sym = make_function_pointer(def, defobj); 3987 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3988 sym = rtld_resolve_ifunc(defobj, def); 3989 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3990 ti.ti_module = defobj->tlsindex; 3991 ti.ti_offset = def->st_value; 3992 sym = __tls_get_addr(&ti); 3993 } else 3994 sym = defobj->relocbase + def->st_value; 3995 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3996 return (sym); 3997 } 3998 3999 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "", 4000 ve != NULL ? ve->name : ""); 4001 lock_release(rtld_bind_lock, &lockstate); 4002 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 4003 return (NULL); 4004 } 4005 4006 void * 4007 dlsym(void *handle, const char *name) 4008 { 4009 return (do_dlsym(handle, name, __builtin_return_address(0), NULL, 4010 SYMLOOK_DLSYM)); 4011 } 4012 4013 dlfunc_t 4014 dlfunc(void *handle, const char *name) 4015 { 4016 union { 4017 void *d; 4018 dlfunc_t f; 4019 } rv; 4020 4021 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 4022 SYMLOOK_DLSYM); 4023 return (rv.f); 4024 } 4025 4026 void * 4027 dlvsym(void *handle, const char *name, const char *version) 4028 { 4029 Ver_Entry ventry; 4030 4031 ventry.name = version; 4032 ventry.file = NULL; 4033 ventry.hash = elf_hash(version); 4034 ventry.flags= 0; 4035 return (do_dlsym(handle, name, __builtin_return_address(0), &ventry, 4036 SYMLOOK_DLSYM)); 4037 } 4038 4039 int 4040 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 4041 { 4042 const Obj_Entry *obj; 4043 RtldLockState lockstate; 4044 4045 rlock_acquire(rtld_bind_lock, &lockstate); 4046 obj = obj_from_addr(addr); 4047 if (obj == NULL) { 4048 _rtld_error("No shared object contains address"); 4049 lock_release(rtld_bind_lock, &lockstate); 4050 return (0); 4051 } 4052 rtld_fill_dl_phdr_info(obj, phdr_info); 4053 lock_release(rtld_bind_lock, &lockstate); 4054 return (1); 4055 } 4056 4057 int 4058 dladdr(const void *addr, Dl_info *info) 4059 { 4060 const Obj_Entry *obj; 4061 const Elf_Sym *def; 4062 void *symbol_addr; 4063 unsigned long symoffset; 4064 RtldLockState lockstate; 4065 4066 rlock_acquire(rtld_bind_lock, &lockstate); 4067 obj = obj_from_addr(addr); 4068 if (obj == NULL) { 4069 _rtld_error("No shared object contains address"); 4070 lock_release(rtld_bind_lock, &lockstate); 4071 return (0); 4072 } 4073 info->dli_fname = obj->path; 4074 info->dli_fbase = obj->mapbase; 4075 info->dli_saddr = (void *)0; 4076 info->dli_sname = NULL; 4077 4078 /* 4079 * Walk the symbol list looking for the symbol whose address is 4080 * closest to the address sent in. 4081 */ 4082 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 4083 def = obj->symtab + symoffset; 4084 4085 /* 4086 * For skip the symbol if st_shndx is either SHN_UNDEF or 4087 * SHN_COMMON. 4088 */ 4089 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 4090 continue; 4091 4092 /* 4093 * If the symbol is greater than the specified address, or if it 4094 * is further away from addr than the current nearest symbol, 4095 * then reject it. 4096 */ 4097 symbol_addr = obj->relocbase + def->st_value; 4098 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 4099 continue; 4100 4101 /* Update our idea of the nearest symbol. */ 4102 info->dli_sname = obj->strtab + def->st_name; 4103 info->dli_saddr = symbol_addr; 4104 4105 /* Exact match? */ 4106 if (info->dli_saddr == addr) 4107 break; 4108 } 4109 lock_release(rtld_bind_lock, &lockstate); 4110 return (1); 4111 } 4112 4113 int 4114 dlinfo(void *handle, int request, void *p) 4115 { 4116 const Obj_Entry *obj; 4117 RtldLockState lockstate; 4118 int error; 4119 4120 rlock_acquire(rtld_bind_lock, &lockstate); 4121 4122 if (handle == NULL || handle == RTLD_SELF) { 4123 void *retaddr; 4124 4125 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 4126 if ((obj = obj_from_addr(retaddr)) == NULL) 4127 _rtld_error("Cannot determine caller's shared object"); 4128 } else 4129 obj = dlcheck(handle); 4130 4131 if (obj == NULL) { 4132 lock_release(rtld_bind_lock, &lockstate); 4133 return (-1); 4134 } 4135 4136 error = 0; 4137 switch (request) { 4138 case RTLD_DI_LINKMAP: 4139 *((struct link_map const **)p) = &obj->linkmap; 4140 break; 4141 case RTLD_DI_ORIGIN: 4142 error = rtld_dirname(obj->path, p); 4143 break; 4144 4145 case RTLD_DI_SERINFOSIZE: 4146 case RTLD_DI_SERINFO: 4147 error = do_search_info(obj, request, (struct dl_serinfo *)p); 4148 break; 4149 4150 default: 4151 _rtld_error("Invalid request %d passed to dlinfo()", request); 4152 error = -1; 4153 } 4154 4155 lock_release(rtld_bind_lock, &lockstate); 4156 4157 return (error); 4158 } 4159 4160 static void 4161 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 4162 { 4163 uintptr_t **dtvp; 4164 4165 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 4166 phdr_info->dlpi_name = obj->path; 4167 phdr_info->dlpi_phdr = obj->phdr; 4168 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 4169 phdr_info->dlpi_tls_modid = obj->tlsindex; 4170 dtvp = &_tcb_get()->tcb_dtv; 4171 phdr_info->dlpi_tls_data = (char *)tls_get_addr_slow(dtvp, 4172 obj->tlsindex, 0, true) + TLS_DTV_OFFSET; 4173 phdr_info->dlpi_adds = obj_loads; 4174 phdr_info->dlpi_subs = obj_loads - obj_count; 4175 } 4176 4177 int 4178 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 4179 { 4180 struct dl_phdr_info phdr_info; 4181 Obj_Entry *obj, marker; 4182 RtldLockState bind_lockstate, phdr_lockstate; 4183 int error; 4184 4185 init_marker(&marker); 4186 error = 0; 4187 4188 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 4189 wlock_acquire(rtld_bind_lock, &bind_lockstate); 4190 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 4191 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 4192 rtld_fill_dl_phdr_info(obj, &phdr_info); 4193 hold_object(obj); 4194 lock_release(rtld_bind_lock, &bind_lockstate); 4195 4196 error = callback(&phdr_info, sizeof phdr_info, param); 4197 4198 wlock_acquire(rtld_bind_lock, &bind_lockstate); 4199 unhold_object(obj); 4200 obj = globallist_next(&marker); 4201 TAILQ_REMOVE(&obj_list, &marker, next); 4202 if (error != 0) { 4203 lock_release(rtld_bind_lock, &bind_lockstate); 4204 lock_release(rtld_phdr_lock, &phdr_lockstate); 4205 return (error); 4206 } 4207 } 4208 4209 if (error == 0) { 4210 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 4211 lock_release(rtld_bind_lock, &bind_lockstate); 4212 error = callback(&phdr_info, sizeof(phdr_info), param); 4213 } 4214 lock_release(rtld_phdr_lock, &phdr_lockstate); 4215 return (error); 4216 } 4217 4218 static void * 4219 fill_search_info(const char *dir, size_t dirlen, void *param) 4220 { 4221 struct fill_search_info_args *arg; 4222 4223 arg = param; 4224 4225 if (arg->request == RTLD_DI_SERINFOSIZE) { 4226 arg->serinfo->dls_cnt ++; 4227 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 4228 } else { 4229 struct dl_serpath *s_entry; 4230 4231 s_entry = arg->serpath; 4232 s_entry->dls_name = arg->strspace; 4233 s_entry->dls_flags = arg->flags; 4234 4235 strncpy(arg->strspace, dir, dirlen); 4236 arg->strspace[dirlen] = '\0'; 4237 4238 arg->strspace += dirlen + 1; 4239 arg->serpath++; 4240 } 4241 4242 return (NULL); 4243 } 4244 4245 static int 4246 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 4247 { 4248 struct dl_serinfo _info; 4249 struct fill_search_info_args args; 4250 4251 args.request = RTLD_DI_SERINFOSIZE; 4252 args.serinfo = &_info; 4253 4254 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 4255 _info.dls_cnt = 0; 4256 4257 path_enumerate(obj->rpath, fill_search_info, NULL, &args); 4258 path_enumerate(ld_library_path, fill_search_info, NULL, &args); 4259 path_enumerate(obj->runpath, fill_search_info, NULL, &args); 4260 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args); 4261 if (!obj->z_nodeflib) 4262 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args); 4263 4264 4265 if (request == RTLD_DI_SERINFOSIZE) { 4266 info->dls_size = _info.dls_size; 4267 info->dls_cnt = _info.dls_cnt; 4268 return (0); 4269 } 4270 4271 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 4272 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 4273 return (-1); 4274 } 4275 4276 args.request = RTLD_DI_SERINFO; 4277 args.serinfo = info; 4278 args.serpath = &info->dls_serpath[0]; 4279 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 4280 4281 args.flags = LA_SER_RUNPATH; 4282 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL) 4283 return (-1); 4284 4285 args.flags = LA_SER_LIBPATH; 4286 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL) 4287 return (-1); 4288 4289 args.flags = LA_SER_RUNPATH; 4290 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL) 4291 return (-1); 4292 4293 args.flags = LA_SER_CONFIG; 4294 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args) 4295 != NULL) 4296 return (-1); 4297 4298 args.flags = LA_SER_DEFAULT; 4299 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path, 4300 fill_search_info, NULL, &args) != NULL) 4301 return (-1); 4302 return (0); 4303 } 4304 4305 static int 4306 rtld_dirname(const char *path, char *bname) 4307 { 4308 const char *endp; 4309 4310 /* Empty or NULL string gets treated as "." */ 4311 if (path == NULL || *path == '\0') { 4312 bname[0] = '.'; 4313 bname[1] = '\0'; 4314 return (0); 4315 } 4316 4317 /* Strip trailing slashes */ 4318 endp = path + strlen(path) - 1; 4319 while (endp > path && *endp == '/') 4320 endp--; 4321 4322 /* Find the start of the dir */ 4323 while (endp > path && *endp != '/') 4324 endp--; 4325 4326 /* Either the dir is "/" or there are no slashes */ 4327 if (endp == path) { 4328 bname[0] = *endp == '/' ? '/' : '.'; 4329 bname[1] = '\0'; 4330 return (0); 4331 } else { 4332 do { 4333 endp--; 4334 } while (endp > path && *endp == '/'); 4335 } 4336 4337 if (endp - path + 2 > PATH_MAX) 4338 { 4339 _rtld_error("Filename is too long: %s", path); 4340 return(-1); 4341 } 4342 4343 strncpy(bname, path, endp - path + 1); 4344 bname[endp - path + 1] = '\0'; 4345 return (0); 4346 } 4347 4348 static int 4349 rtld_dirname_abs(const char *path, char *base) 4350 { 4351 char *last; 4352 4353 if (realpath(path, base) == NULL) { 4354 _rtld_error("realpath \"%s\" failed (%s)", path, 4355 rtld_strerror(errno)); 4356 return (-1); 4357 } 4358 dbg("%s -> %s", path, base); 4359 last = strrchr(base, '/'); 4360 if (last == NULL) { 4361 _rtld_error("non-abs result from realpath \"%s\"", path); 4362 return (-1); 4363 } 4364 if (last != base) 4365 *last = '\0'; 4366 return (0); 4367 } 4368 4369 static void 4370 linkmap_add(Obj_Entry *obj) 4371 { 4372 struct link_map *l, *prev; 4373 4374 l = &obj->linkmap; 4375 l->l_name = obj->path; 4376 l->l_base = obj->mapbase; 4377 l->l_ld = obj->dynamic; 4378 l->l_addr = obj->relocbase; 4379 4380 if (r_debug.r_map == NULL) { 4381 r_debug.r_map = l; 4382 return; 4383 } 4384 4385 /* 4386 * Scan to the end of the list, but not past the entry for the 4387 * dynamic linker, which we want to keep at the very end. 4388 */ 4389 for (prev = r_debug.r_map; 4390 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 4391 prev = prev->l_next) 4392 ; 4393 4394 /* Link in the new entry. */ 4395 l->l_prev = prev; 4396 l->l_next = prev->l_next; 4397 if (l->l_next != NULL) 4398 l->l_next->l_prev = l; 4399 prev->l_next = l; 4400 } 4401 4402 static void 4403 linkmap_delete(Obj_Entry *obj) 4404 { 4405 struct link_map *l; 4406 4407 l = &obj->linkmap; 4408 if (l->l_prev == NULL) { 4409 if ((r_debug.r_map = l->l_next) != NULL) 4410 l->l_next->l_prev = NULL; 4411 return; 4412 } 4413 4414 if ((l->l_prev->l_next = l->l_next) != NULL) 4415 l->l_next->l_prev = l->l_prev; 4416 } 4417 4418 /* 4419 * Function for the debugger to set a breakpoint on to gain control. 4420 * 4421 * The two parameters allow the debugger to easily find and determine 4422 * what the runtime loader is doing and to whom it is doing it. 4423 * 4424 * When the loadhook trap is hit (r_debug_state, set at program 4425 * initialization), the arguments can be found on the stack: 4426 * 4427 * +8 struct link_map *m 4428 * +4 struct r_debug *rd 4429 * +0 RetAddr 4430 */ 4431 void 4432 r_debug_state(struct r_debug* rd __unused, struct link_map *m __unused) 4433 { 4434 /* 4435 * The following is a hack to force the compiler to emit calls to 4436 * this function, even when optimizing. If the function is empty, 4437 * the compiler is not obliged to emit any code for calls to it, 4438 * even when marked __noinline. However, gdb depends on those 4439 * calls being made. 4440 */ 4441 __compiler_membar(); 4442 } 4443 4444 /* 4445 * A function called after init routines have completed. This can be used to 4446 * break before a program's entry routine is called, and can be used when 4447 * main is not available in the symbol table. 4448 */ 4449 void 4450 _r_debug_postinit(struct link_map *m __unused) 4451 { 4452 4453 /* See r_debug_state(). */ 4454 __compiler_membar(); 4455 } 4456 4457 static void 4458 release_object(Obj_Entry *obj) 4459 { 4460 4461 if (obj->holdcount > 0) { 4462 obj->unholdfree = true; 4463 return; 4464 } 4465 munmap(obj->mapbase, obj->mapsize); 4466 linkmap_delete(obj); 4467 obj_free(obj); 4468 } 4469 4470 /* 4471 * Get address of the pointer variable in the main program. 4472 * Prefer non-weak symbol over the weak one. 4473 */ 4474 static const void ** 4475 get_program_var_addr(const char *name, RtldLockState *lockstate) 4476 { 4477 SymLook req; 4478 DoneList donelist; 4479 4480 symlook_init(&req, name); 4481 req.lockstate = lockstate; 4482 donelist_init(&donelist); 4483 if (symlook_global(&req, &donelist) != 0) 4484 return (NULL); 4485 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 4486 return ((const void **)make_function_pointer(req.sym_out, 4487 req.defobj_out)); 4488 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 4489 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 4490 else 4491 return ((const void **)(req.defobj_out->relocbase + 4492 req.sym_out->st_value)); 4493 } 4494 4495 /* 4496 * Set a pointer variable in the main program to the given value. This 4497 * is used to set key variables such as "environ" before any of the 4498 * init functions are called. 4499 */ 4500 static void 4501 set_program_var(const char *name, const void *value) 4502 { 4503 const void **addr; 4504 4505 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 4506 dbg("\"%s\": *%p <-- %p", name, addr, value); 4507 *addr = value; 4508 } 4509 } 4510 4511 /* 4512 * Search the global objects, including dependencies and main object, 4513 * for the given symbol. 4514 */ 4515 static int 4516 symlook_global(SymLook *req, DoneList *donelist) 4517 { 4518 SymLook req1; 4519 const Objlist_Entry *elm; 4520 int res; 4521 4522 symlook_init_from_req(&req1, req); 4523 4524 /* Search all objects loaded at program start up. */ 4525 if (req->defobj_out == NULL || (ld_dynamic_weak && 4526 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK)) { 4527 res = symlook_list(&req1, &list_main, donelist); 4528 if (res == 0 && (!ld_dynamic_weak || req->defobj_out == NULL || 4529 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4530 req->sym_out = req1.sym_out; 4531 req->defobj_out = req1.defobj_out; 4532 assert(req->defobj_out != NULL); 4533 } 4534 } 4535 4536 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 4537 STAILQ_FOREACH(elm, &list_global, link) { 4538 if (req->defobj_out != NULL && (!ld_dynamic_weak || 4539 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)) 4540 break; 4541 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 4542 if (res == 0 && (req->defobj_out == NULL || 4543 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4544 req->sym_out = req1.sym_out; 4545 req->defobj_out = req1.defobj_out; 4546 assert(req->defobj_out != NULL); 4547 } 4548 } 4549 4550 return (req->sym_out != NULL ? 0 : ESRCH); 4551 } 4552 4553 /* 4554 * Given a symbol name in a referencing object, find the corresponding 4555 * definition of the symbol. Returns a pointer to the symbol, or NULL if 4556 * no definition was found. Returns a pointer to the Obj_Entry of the 4557 * defining object via the reference parameter DEFOBJ_OUT. 4558 */ 4559 static int 4560 symlook_default(SymLook *req, const Obj_Entry *refobj) 4561 { 4562 DoneList donelist; 4563 const Objlist_Entry *elm; 4564 SymLook req1; 4565 int res; 4566 4567 donelist_init(&donelist); 4568 symlook_init_from_req(&req1, req); 4569 4570 /* 4571 * Look first in the referencing object if linked symbolically, 4572 * and similarly handle protected symbols. 4573 */ 4574 res = symlook_obj(&req1, refobj); 4575 if (res == 0 && (refobj->symbolic || 4576 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) { 4577 req->sym_out = req1.sym_out; 4578 req->defobj_out = req1.defobj_out; 4579 assert(req->defobj_out != NULL); 4580 } 4581 if (refobj->symbolic || req->defobj_out != NULL) 4582 donelist_check(&donelist, refobj); 4583 4584 if (!refobj->deepbind) 4585 symlook_global(req, &donelist); 4586 4587 /* Search all dlopened DAGs containing the referencing object. */ 4588 STAILQ_FOREACH(elm, &refobj->dldags, link) { 4589 if (req->sym_out != NULL && (!ld_dynamic_weak || 4590 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)) 4591 break; 4592 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 4593 if (res == 0 && (req->sym_out == NULL || 4594 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4595 req->sym_out = req1.sym_out; 4596 req->defobj_out = req1.defobj_out; 4597 assert(req->defobj_out != NULL); 4598 } 4599 } 4600 4601 if (refobj->deepbind) 4602 symlook_global(req, &donelist); 4603 4604 /* 4605 * Search the dynamic linker itself, and possibly resolve the 4606 * symbol from there. This is how the application links to 4607 * dynamic linker services such as dlopen. 4608 */ 4609 if (req->sym_out == NULL || 4610 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4611 res = symlook_obj(&req1, &obj_rtld); 4612 if (res == 0) { 4613 req->sym_out = req1.sym_out; 4614 req->defobj_out = req1.defobj_out; 4615 assert(req->defobj_out != NULL); 4616 } 4617 } 4618 4619 return (req->sym_out != NULL ? 0 : ESRCH); 4620 } 4621 4622 static int 4623 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 4624 { 4625 const Elf_Sym *def; 4626 const Obj_Entry *defobj; 4627 const Objlist_Entry *elm; 4628 SymLook req1; 4629 int res; 4630 4631 def = NULL; 4632 defobj = NULL; 4633 STAILQ_FOREACH(elm, objlist, link) { 4634 if (donelist_check(dlp, elm->obj)) 4635 continue; 4636 symlook_init_from_req(&req1, req); 4637 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 4638 if (def == NULL || (ld_dynamic_weak && 4639 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4640 def = req1.sym_out; 4641 defobj = req1.defobj_out; 4642 if (!ld_dynamic_weak || ELF_ST_BIND(def->st_info) != STB_WEAK) 4643 break; 4644 } 4645 } 4646 } 4647 if (def != NULL) { 4648 req->sym_out = def; 4649 req->defobj_out = defobj; 4650 return (0); 4651 } 4652 return (ESRCH); 4653 } 4654 4655 /* 4656 * Search the chain of DAGS cointed to by the given Needed_Entry 4657 * for a symbol of the given name. Each DAG is scanned completely 4658 * before advancing to the next one. Returns a pointer to the symbol, 4659 * or NULL if no definition was found. 4660 */ 4661 static int 4662 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 4663 { 4664 const Elf_Sym *def; 4665 const Needed_Entry *n; 4666 const Obj_Entry *defobj; 4667 SymLook req1; 4668 int res; 4669 4670 def = NULL; 4671 defobj = NULL; 4672 symlook_init_from_req(&req1, req); 4673 for (n = needed; n != NULL; n = n->next) { 4674 if (n->obj == NULL || 4675 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 4676 continue; 4677 if (def == NULL || (ld_dynamic_weak && 4678 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4679 def = req1.sym_out; 4680 defobj = req1.defobj_out; 4681 if (!ld_dynamic_weak || ELF_ST_BIND(def->st_info) != STB_WEAK) 4682 break; 4683 } 4684 } 4685 if (def != NULL) { 4686 req->sym_out = def; 4687 req->defobj_out = defobj; 4688 return (0); 4689 } 4690 return (ESRCH); 4691 } 4692 4693 /* 4694 * Search the symbol table of a single shared object for a symbol of 4695 * the given name and version, if requested. Returns a pointer to the 4696 * symbol, or NULL if no definition was found. If the object is 4697 * filter, return filtered symbol from filtee. 4698 * 4699 * The symbol's hash value is passed in for efficiency reasons; that 4700 * eliminates many recomputations of the hash value. 4701 */ 4702 int 4703 symlook_obj(SymLook *req, const Obj_Entry *obj) 4704 { 4705 DoneList donelist; 4706 SymLook req1; 4707 int flags, res, mres; 4708 4709 /* 4710 * If there is at least one valid hash at this point, we prefer to 4711 * use the faster GNU version if available. 4712 */ 4713 if (obj->valid_hash_gnu) 4714 mres = symlook_obj1_gnu(req, obj); 4715 else if (obj->valid_hash_sysv) 4716 mres = symlook_obj1_sysv(req, obj); 4717 else 4718 return (EINVAL); 4719 4720 if (mres == 0) { 4721 if (obj->needed_filtees != NULL) { 4722 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4723 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4724 donelist_init(&donelist); 4725 symlook_init_from_req(&req1, req); 4726 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 4727 if (res == 0) { 4728 req->sym_out = req1.sym_out; 4729 req->defobj_out = req1.defobj_out; 4730 } 4731 return (res); 4732 } 4733 if (obj->needed_aux_filtees != NULL) { 4734 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4735 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4736 donelist_init(&donelist); 4737 symlook_init_from_req(&req1, req); 4738 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 4739 if (res == 0) { 4740 req->sym_out = req1.sym_out; 4741 req->defobj_out = req1.defobj_out; 4742 return (res); 4743 } 4744 } 4745 } 4746 return (mres); 4747 } 4748 4749 /* Symbol match routine common to both hash functions */ 4750 static bool 4751 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4752 const unsigned long symnum) 4753 { 4754 Elf_Versym verndx; 4755 const Elf_Sym *symp; 4756 const char *strp; 4757 4758 symp = obj->symtab + symnum; 4759 strp = obj->strtab + symp->st_name; 4760 4761 switch (ELF_ST_TYPE(symp->st_info)) { 4762 case STT_FUNC: 4763 case STT_NOTYPE: 4764 case STT_OBJECT: 4765 case STT_COMMON: 4766 case STT_GNU_IFUNC: 4767 if (symp->st_value == 0) 4768 return (false); 4769 /* fallthrough */ 4770 case STT_TLS: 4771 if (symp->st_shndx != SHN_UNDEF) 4772 break; 4773 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4774 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4775 break; 4776 /* fallthrough */ 4777 default: 4778 return (false); 4779 } 4780 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4781 return (false); 4782 4783 if (req->ventry == NULL) { 4784 if (obj->versyms != NULL) { 4785 verndx = VER_NDX(obj->versyms[symnum]); 4786 if (verndx > obj->vernum) { 4787 _rtld_error( 4788 "%s: symbol %s references wrong version %d", 4789 obj->path, obj->strtab + symnum, verndx); 4790 return (false); 4791 } 4792 /* 4793 * If we are not called from dlsym (i.e. this 4794 * is a normal relocation from unversioned 4795 * binary), accept the symbol immediately if 4796 * it happens to have first version after this 4797 * shared object became versioned. Otherwise, 4798 * if symbol is versioned and not hidden, 4799 * remember it. If it is the only symbol with 4800 * this name exported by the shared object, it 4801 * will be returned as a match by the calling 4802 * function. If symbol is global (verndx < 2) 4803 * accept it unconditionally. 4804 */ 4805 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4806 verndx == VER_NDX_GIVEN) { 4807 result->sym_out = symp; 4808 return (true); 4809 } 4810 else if (verndx >= VER_NDX_GIVEN) { 4811 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4812 == 0) { 4813 if (result->vsymp == NULL) 4814 result->vsymp = symp; 4815 result->vcount++; 4816 } 4817 return (false); 4818 } 4819 } 4820 result->sym_out = symp; 4821 return (true); 4822 } 4823 if (obj->versyms == NULL) { 4824 if (object_match_name(obj, req->ventry->name)) { 4825 _rtld_error("%s: object %s should provide version %s " 4826 "for symbol %s", obj_rtld.path, obj->path, 4827 req->ventry->name, obj->strtab + symnum); 4828 return (false); 4829 } 4830 } else { 4831 verndx = VER_NDX(obj->versyms[symnum]); 4832 if (verndx > obj->vernum) { 4833 _rtld_error("%s: symbol %s references wrong version %d", 4834 obj->path, obj->strtab + symnum, verndx); 4835 return (false); 4836 } 4837 if (obj->vertab[verndx].hash != req->ventry->hash || 4838 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4839 /* 4840 * Version does not match. Look if this is a 4841 * global symbol and if it is not hidden. If 4842 * global symbol (verndx < 2) is available, 4843 * use it. Do not return symbol if we are 4844 * called by dlvsym, because dlvsym looks for 4845 * a specific version and default one is not 4846 * what dlvsym wants. 4847 */ 4848 if ((req->flags & SYMLOOK_DLSYM) || 4849 (verndx >= VER_NDX_GIVEN) || 4850 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4851 return (false); 4852 } 4853 } 4854 result->sym_out = symp; 4855 return (true); 4856 } 4857 4858 /* 4859 * Search for symbol using SysV hash function. 4860 * obj->buckets is known not to be NULL at this point; the test for this was 4861 * performed with the obj->valid_hash_sysv assignment. 4862 */ 4863 static int 4864 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4865 { 4866 unsigned long symnum; 4867 Sym_Match_Result matchres; 4868 4869 matchres.sym_out = NULL; 4870 matchres.vsymp = NULL; 4871 matchres.vcount = 0; 4872 4873 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4874 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4875 if (symnum >= obj->nchains) 4876 return (ESRCH); /* Bad object */ 4877 4878 if (matched_symbol(req, obj, &matchres, symnum)) { 4879 req->sym_out = matchres.sym_out; 4880 req->defobj_out = obj; 4881 return (0); 4882 } 4883 } 4884 if (matchres.vcount == 1) { 4885 req->sym_out = matchres.vsymp; 4886 req->defobj_out = obj; 4887 return (0); 4888 } 4889 return (ESRCH); 4890 } 4891 4892 /* Search for symbol using GNU hash function */ 4893 static int 4894 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4895 { 4896 Elf_Addr bloom_word; 4897 const Elf32_Word *hashval; 4898 Elf32_Word bucket; 4899 Sym_Match_Result matchres; 4900 unsigned int h1, h2; 4901 unsigned long symnum; 4902 4903 matchres.sym_out = NULL; 4904 matchres.vsymp = NULL; 4905 matchres.vcount = 0; 4906 4907 /* Pick right bitmask word from Bloom filter array */ 4908 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4909 obj->maskwords_bm_gnu]; 4910 4911 /* Calculate modulus word size of gnu hash and its derivative */ 4912 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4913 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4914 4915 /* Filter out the "definitely not in set" queries */ 4916 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4917 return (ESRCH); 4918 4919 /* Locate hash chain and corresponding value element*/ 4920 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4921 if (bucket == 0) 4922 return (ESRCH); 4923 hashval = &obj->chain_zero_gnu[bucket]; 4924 do { 4925 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4926 symnum = hashval - obj->chain_zero_gnu; 4927 if (matched_symbol(req, obj, &matchres, symnum)) { 4928 req->sym_out = matchres.sym_out; 4929 req->defobj_out = obj; 4930 return (0); 4931 } 4932 } 4933 } while ((*hashval++ & 1) == 0); 4934 if (matchres.vcount == 1) { 4935 req->sym_out = matchres.vsymp; 4936 req->defobj_out = obj; 4937 return (0); 4938 } 4939 return (ESRCH); 4940 } 4941 4942 static void 4943 trace_calc_fmts(const char **main_local, const char **fmt1, const char **fmt2) 4944 { 4945 *main_local = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_PROGNAME); 4946 if (*main_local == NULL) 4947 *main_local = ""; 4948 4949 *fmt1 = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT1); 4950 if (*fmt1 == NULL) 4951 *fmt1 = "\t%o => %p (%x)\n"; 4952 4953 *fmt2 = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT2); 4954 if (*fmt2 == NULL) 4955 *fmt2 = "\t%o (%x)\n"; 4956 } 4957 4958 static void 4959 trace_print_obj(Obj_Entry *obj, const char *name, const char *path, 4960 const char *main_local, const char *fmt1, const char *fmt2) 4961 { 4962 const char *fmt; 4963 int c; 4964 4965 if (fmt1 == NULL) 4966 fmt = fmt2; 4967 else 4968 /* XXX bogus */ 4969 fmt = strncmp(name, "lib", 3) == 0 ? fmt1 : fmt2; 4970 4971 while ((c = *fmt++) != '\0') { 4972 switch (c) { 4973 default: 4974 rtld_putchar(c); 4975 continue; 4976 case '\\': 4977 switch (c = *fmt) { 4978 case '\0': 4979 continue; 4980 case 'n': 4981 rtld_putchar('\n'); 4982 break; 4983 case 't': 4984 rtld_putchar('\t'); 4985 break; 4986 } 4987 break; 4988 case '%': 4989 switch (c = *fmt) { 4990 case '\0': 4991 continue; 4992 case '%': 4993 default: 4994 rtld_putchar(c); 4995 break; 4996 case 'A': 4997 rtld_putstr(main_local); 4998 break; 4999 case 'a': 5000 rtld_putstr(obj_main->path); 5001 break; 5002 case 'o': 5003 rtld_putstr(name); 5004 break; 5005 case 'p': 5006 rtld_putstr(path); 5007 break; 5008 case 'x': 5009 rtld_printf("%p", obj != NULL ? 5010 obj->mapbase : NULL); 5011 break; 5012 } 5013 break; 5014 } 5015 ++fmt; 5016 } 5017 } 5018 5019 static void 5020 trace_loaded_objects(Obj_Entry *obj, bool show_preload) 5021 { 5022 const char *fmt1, *fmt2, *main_local; 5023 const char *name, *path; 5024 bool first_spurious, list_containers; 5025 5026 trace_calc_fmts(&main_local, &fmt1, &fmt2); 5027 list_containers = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_ALL) != NULL; 5028 5029 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 5030 Needed_Entry *needed; 5031 5032 if (obj->marker) 5033 continue; 5034 if (list_containers && obj->needed != NULL) 5035 rtld_printf("%s:\n", obj->path); 5036 for (needed = obj->needed; needed; needed = needed->next) { 5037 if (needed->obj != NULL) { 5038 if (needed->obj->traced && !list_containers) 5039 continue; 5040 needed->obj->traced = true; 5041 path = needed->obj->path; 5042 } else 5043 path = "not found"; 5044 5045 name = obj->strtab + needed->name; 5046 trace_print_obj(needed->obj, name, path, main_local, 5047 fmt1, fmt2); 5048 } 5049 } 5050 5051 if (show_preload) { 5052 if (ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT2) == NULL) 5053 fmt2 = "\t%p (%x)\n"; 5054 first_spurious = true; 5055 5056 TAILQ_FOREACH(obj, &obj_list, next) { 5057 if (obj->marker || obj == obj_main || obj->traced) 5058 continue; 5059 5060 if (list_containers && first_spurious) { 5061 rtld_printf("[preloaded]\n"); 5062 first_spurious = false; 5063 } 5064 5065 Name_Entry *fname = STAILQ_FIRST(&obj->names); 5066 name = fname == NULL ? "<unknown>" : fname->name; 5067 trace_print_obj(obj, name, obj->path, main_local, 5068 NULL, fmt2); 5069 } 5070 } 5071 } 5072 5073 /* 5074 * Unload a dlopened object and its dependencies from memory and from 5075 * our data structures. It is assumed that the DAG rooted in the 5076 * object has already been unreferenced, and that the object has a 5077 * reference count of 0. 5078 */ 5079 static void 5080 unload_object(Obj_Entry *root, RtldLockState *lockstate) 5081 { 5082 Obj_Entry marker, *obj, *next; 5083 5084 assert(root->refcount == 0); 5085 5086 /* 5087 * Pass over the DAG removing unreferenced objects from 5088 * appropriate lists. 5089 */ 5090 unlink_object(root); 5091 5092 /* Unmap all objects that are no longer referenced. */ 5093 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) { 5094 next = TAILQ_NEXT(obj, next); 5095 if (obj->marker || obj->refcount != 0) 5096 continue; 5097 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 5098 obj->mapsize, 0, obj->path); 5099 dbg("unloading \"%s\"", obj->path); 5100 /* 5101 * Unlink the object now to prevent new references from 5102 * being acquired while the bind lock is dropped in 5103 * recursive dlclose() invocations. 5104 */ 5105 TAILQ_REMOVE(&obj_list, obj, next); 5106 obj_count--; 5107 5108 if (obj->filtees_loaded) { 5109 if (next != NULL) { 5110 init_marker(&marker); 5111 TAILQ_INSERT_BEFORE(next, &marker, next); 5112 unload_filtees(obj, lockstate); 5113 next = TAILQ_NEXT(&marker, next); 5114 TAILQ_REMOVE(&obj_list, &marker, next); 5115 } else 5116 unload_filtees(obj, lockstate); 5117 } 5118 release_object(obj); 5119 } 5120 } 5121 5122 static void 5123 unlink_object(Obj_Entry *root) 5124 { 5125 Objlist_Entry *elm; 5126 5127 if (root->refcount == 0) { 5128 /* Remove the object from the RTLD_GLOBAL list. */ 5129 objlist_remove(&list_global, root); 5130 5131 /* Remove the object from all objects' DAG lists. */ 5132 STAILQ_FOREACH(elm, &root->dagmembers, link) { 5133 objlist_remove(&elm->obj->dldags, root); 5134 if (elm->obj != root) 5135 unlink_object(elm->obj); 5136 } 5137 } 5138 } 5139 5140 static void 5141 ref_dag(Obj_Entry *root) 5142 { 5143 Objlist_Entry *elm; 5144 5145 assert(root->dag_inited); 5146 STAILQ_FOREACH(elm, &root->dagmembers, link) 5147 elm->obj->refcount++; 5148 } 5149 5150 static void 5151 unref_dag(Obj_Entry *root) 5152 { 5153 Objlist_Entry *elm; 5154 5155 assert(root->dag_inited); 5156 STAILQ_FOREACH(elm, &root->dagmembers, link) 5157 elm->obj->refcount--; 5158 } 5159 5160 /* 5161 * Common code for MD __tls_get_addr(). 5162 */ 5163 static void * 5164 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset, bool locked) 5165 { 5166 Elf_Addr *newdtv, *dtv; 5167 RtldLockState lockstate; 5168 int to_copy; 5169 5170 dtv = *dtvp; 5171 /* Check dtv generation in case new modules have arrived */ 5172 if (dtv[0] != tls_dtv_generation) { 5173 if (!locked) 5174 wlock_acquire(rtld_bind_lock, &lockstate); 5175 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5176 to_copy = dtv[1]; 5177 if (to_copy > tls_max_index) 5178 to_copy = tls_max_index; 5179 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 5180 newdtv[0] = tls_dtv_generation; 5181 newdtv[1] = tls_max_index; 5182 free(dtv); 5183 if (!locked) 5184 lock_release(rtld_bind_lock, &lockstate); 5185 dtv = *dtvp = newdtv; 5186 } 5187 5188 /* Dynamically allocate module TLS if necessary */ 5189 if (dtv[index + 1] == 0) { 5190 /* Signal safe, wlock will block out signals. */ 5191 if (!locked) 5192 wlock_acquire(rtld_bind_lock, &lockstate); 5193 if (!dtv[index + 1]) 5194 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 5195 if (!locked) 5196 lock_release(rtld_bind_lock, &lockstate); 5197 } 5198 return ((void *)(dtv[index + 1] + offset)); 5199 } 5200 5201 void * 5202 tls_get_addr_common(uintptr_t **dtvp, int index, size_t offset) 5203 { 5204 uintptr_t *dtv; 5205 5206 dtv = *dtvp; 5207 /* Check dtv generation in case new modules have arrived */ 5208 if (__predict_true(dtv[0] == tls_dtv_generation && 5209 dtv[index + 1] != 0)) 5210 return ((void *)(dtv[index + 1] + offset)); 5211 return (tls_get_addr_slow(dtvp, index, offset, false)); 5212 } 5213 5214 #ifdef TLS_VARIANT_I 5215 5216 /* 5217 * Return pointer to allocated TLS block 5218 */ 5219 static void * 5220 get_tls_block_ptr(void *tcb, size_t tcbsize) 5221 { 5222 size_t extra_size, post_size, pre_size, tls_block_size; 5223 size_t tls_init_align; 5224 5225 tls_init_align = MAX(obj_main->tlsalign, 1); 5226 5227 /* Compute fragments sizes. */ 5228 extra_size = tcbsize - TLS_TCB_SIZE; 5229 post_size = calculate_tls_post_size(tls_init_align); 5230 tls_block_size = tcbsize + post_size; 5231 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 5232 5233 return ((char *)tcb - pre_size - extra_size); 5234 } 5235 5236 /* 5237 * Allocate Static TLS using the Variant I method. 5238 * 5239 * For details on the layout, see lib/libc/gen/tls.c. 5240 * 5241 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as 5242 * it is based on tls_last_offset, and TLS offsets here are really TCB 5243 * offsets, whereas libc's tls_static_space is just the executable's static 5244 * TLS segment. 5245 */ 5246 void * 5247 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 5248 { 5249 Obj_Entry *obj; 5250 char *tls_block; 5251 Elf_Addr *dtv, **tcb; 5252 Elf_Addr addr; 5253 Elf_Addr i; 5254 size_t extra_size, maxalign, post_size, pre_size, tls_block_size; 5255 size_t tls_init_align, tls_init_offset; 5256 5257 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 5258 return (oldtcb); 5259 5260 assert(tcbsize >= TLS_TCB_SIZE); 5261 maxalign = MAX(tcbalign, tls_static_max_align); 5262 tls_init_align = MAX(obj_main->tlsalign, 1); 5263 5264 /* Compute fragmets sizes. */ 5265 extra_size = tcbsize - TLS_TCB_SIZE; 5266 post_size = calculate_tls_post_size(tls_init_align); 5267 tls_block_size = tcbsize + post_size; 5268 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 5269 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size; 5270 5271 /* Allocate whole TLS block */ 5272 tls_block = xmalloc_aligned(tls_block_size, maxalign, 0); 5273 tcb = (Elf_Addr **)(tls_block + pre_size + extra_size); 5274 5275 if (oldtcb != NULL) { 5276 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize), 5277 tls_static_space); 5278 free(get_tls_block_ptr(oldtcb, tcbsize)); 5279 5280 /* Adjust the DTV. */ 5281 dtv = tcb[0]; 5282 for (i = 0; i < dtv[1]; i++) { 5283 if (dtv[i+2] >= (Elf_Addr)oldtcb && 5284 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 5285 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tcb; 5286 } 5287 } 5288 } else { 5289 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5290 tcb[0] = dtv; 5291 dtv[0] = tls_dtv_generation; 5292 dtv[1] = tls_max_index; 5293 5294 for (obj = globallist_curr(objs); obj != NULL; 5295 obj = globallist_next(obj)) { 5296 if (obj->tlsoffset == 0) 5297 continue; 5298 tls_init_offset = obj->tlspoffset & (obj->tlsalign - 1); 5299 addr = (Elf_Addr)tcb + obj->tlsoffset; 5300 if (tls_init_offset > 0) 5301 memset((void *)addr, 0, tls_init_offset); 5302 if (obj->tlsinitsize > 0) { 5303 memcpy((void *)(addr + tls_init_offset), obj->tlsinit, 5304 obj->tlsinitsize); 5305 } 5306 if (obj->tlssize > obj->tlsinitsize) { 5307 memset((void *)(addr + tls_init_offset + obj->tlsinitsize), 5308 0, obj->tlssize - obj->tlsinitsize - tls_init_offset); 5309 } 5310 dtv[obj->tlsindex + 1] = addr; 5311 } 5312 } 5313 5314 return (tcb); 5315 } 5316 5317 void 5318 free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused) 5319 { 5320 Elf_Addr *dtv; 5321 Elf_Addr tlsstart, tlsend; 5322 size_t post_size; 5323 size_t dtvsize, i, tls_init_align __unused; 5324 5325 assert(tcbsize >= TLS_TCB_SIZE); 5326 tls_init_align = MAX(obj_main->tlsalign, 1); 5327 5328 /* Compute fragments sizes. */ 5329 post_size = calculate_tls_post_size(tls_init_align); 5330 5331 tlsstart = (Elf_Addr)tcb + TLS_TCB_SIZE + post_size; 5332 tlsend = (Elf_Addr)tcb + tls_static_space; 5333 5334 dtv = *(Elf_Addr **)tcb; 5335 dtvsize = dtv[1]; 5336 for (i = 0; i < dtvsize; i++) { 5337 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 5338 free((void*)dtv[i+2]); 5339 } 5340 } 5341 free(dtv); 5342 free(get_tls_block_ptr(tcb, tcbsize)); 5343 } 5344 5345 #endif /* TLS_VARIANT_I */ 5346 5347 #ifdef TLS_VARIANT_II 5348 5349 /* 5350 * Allocate Static TLS using the Variant II method. 5351 */ 5352 void * 5353 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 5354 { 5355 Obj_Entry *obj; 5356 size_t size, ralign; 5357 char *tls; 5358 Elf_Addr *dtv, *olddtv; 5359 Elf_Addr segbase, oldsegbase, addr; 5360 size_t i; 5361 5362 ralign = tcbalign; 5363 if (tls_static_max_align > ralign) 5364 ralign = tls_static_max_align; 5365 size = roundup(tls_static_space, ralign) + roundup(tcbsize, ralign); 5366 5367 assert(tcbsize >= 2*sizeof(Elf_Addr)); 5368 tls = xmalloc_aligned(size, ralign, 0 /* XXX */); 5369 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5370 5371 segbase = (Elf_Addr)(tls + roundup(tls_static_space, ralign)); 5372 ((Elf_Addr *)segbase)[0] = segbase; 5373 ((Elf_Addr *)segbase)[1] = (Elf_Addr) dtv; 5374 5375 dtv[0] = tls_dtv_generation; 5376 dtv[1] = tls_max_index; 5377 5378 if (oldtls) { 5379 /* 5380 * Copy the static TLS block over whole. 5381 */ 5382 oldsegbase = (Elf_Addr) oldtls; 5383 memcpy((void *)(segbase - tls_static_space), 5384 (const void *)(oldsegbase - tls_static_space), 5385 tls_static_space); 5386 5387 /* 5388 * If any dynamic TLS blocks have been created tls_get_addr(), 5389 * move them over. 5390 */ 5391 olddtv = ((Elf_Addr **)oldsegbase)[1]; 5392 for (i = 0; i < olddtv[1]; i++) { 5393 if (olddtv[i + 2] < oldsegbase - size || 5394 olddtv[i + 2] > oldsegbase) { 5395 dtv[i + 2] = olddtv[i + 2]; 5396 olddtv[i + 2] = 0; 5397 } 5398 } 5399 5400 /* 5401 * We assume that this block was the one we created with 5402 * allocate_initial_tls(). 5403 */ 5404 free_tls(oldtls, 2 * sizeof(Elf_Addr), sizeof(Elf_Addr)); 5405 } else { 5406 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 5407 if (obj->marker || obj->tlsoffset == 0) 5408 continue; 5409 addr = segbase - obj->tlsoffset; 5410 memset((void *)(addr + obj->tlsinitsize), 5411 0, obj->tlssize - obj->tlsinitsize); 5412 if (obj->tlsinit) { 5413 memcpy((void *)addr, obj->tlsinit, obj->tlsinitsize); 5414 obj->static_tls_copied = true; 5415 } 5416 dtv[obj->tlsindex + 1] = addr; 5417 } 5418 } 5419 5420 return ((void *)segbase); 5421 } 5422 5423 void 5424 free_tls(void *tls, size_t tcbsize __unused, size_t tcbalign) 5425 { 5426 Elf_Addr* dtv; 5427 size_t size, ralign; 5428 int dtvsize, i; 5429 Elf_Addr tlsstart, tlsend; 5430 5431 /* 5432 * Figure out the size of the initial TLS block so that we can 5433 * find stuff which ___tls_get_addr() allocated dynamically. 5434 */ 5435 ralign = tcbalign; 5436 if (tls_static_max_align > ralign) 5437 ralign = tls_static_max_align; 5438 size = roundup(tls_static_space, ralign); 5439 5440 dtv = ((Elf_Addr **)tls)[1]; 5441 dtvsize = dtv[1]; 5442 tlsend = (Elf_Addr)tls; 5443 tlsstart = tlsend - size; 5444 for (i = 0; i < dtvsize; i++) { 5445 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || 5446 dtv[i + 2] > tlsend)) { 5447 free((void *)dtv[i + 2]); 5448 } 5449 } 5450 5451 free((void *)tlsstart); 5452 free((void *)dtv); 5453 } 5454 5455 #endif /* TLS_VARIANT_II */ 5456 5457 /* 5458 * Allocate TLS block for module with given index. 5459 */ 5460 void * 5461 allocate_module_tls(int index) 5462 { 5463 Obj_Entry *obj; 5464 char *p; 5465 5466 TAILQ_FOREACH(obj, &obj_list, next) { 5467 if (obj->marker) 5468 continue; 5469 if (obj->tlsindex == index) 5470 break; 5471 } 5472 if (obj == NULL) { 5473 _rtld_error("Can't find module with TLS index %d", index); 5474 rtld_die(); 5475 } 5476 5477 if (obj->tls_static) { 5478 #ifdef TLS_VARIANT_I 5479 p = (char *)_tcb_get() + obj->tlsoffset + TLS_TCB_SIZE; 5480 #else 5481 p = (char *)_tcb_get() - obj->tlsoffset; 5482 #endif 5483 return (p); 5484 } 5485 5486 obj->tls_dynamic = true; 5487 5488 p = xmalloc_aligned(obj->tlssize, obj->tlsalign, obj->tlspoffset); 5489 memcpy(p, obj->tlsinit, obj->tlsinitsize); 5490 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 5491 return (p); 5492 } 5493 5494 bool 5495 allocate_tls_offset(Obj_Entry *obj) 5496 { 5497 size_t off; 5498 5499 if (obj->tls_dynamic) 5500 return (false); 5501 5502 if (obj->tls_static) 5503 return (true); 5504 5505 if (obj->tlssize == 0) { 5506 obj->tls_static = true; 5507 return (true); 5508 } 5509 5510 if (tls_last_offset == 0) 5511 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign, 5512 obj->tlspoffset); 5513 else 5514 off = calculate_tls_offset(tls_last_offset, tls_last_size, 5515 obj->tlssize, obj->tlsalign, obj->tlspoffset); 5516 5517 obj->tlsoffset = off; 5518 #ifdef TLS_VARIANT_I 5519 off += obj->tlssize; 5520 #endif 5521 5522 /* 5523 * If we have already fixed the size of the static TLS block, we 5524 * must stay within that size. When allocating the static TLS, we 5525 * leave a small amount of space spare to be used for dynamically 5526 * loading modules which use static TLS. 5527 */ 5528 if (tls_static_space != 0) { 5529 if (off > tls_static_space) 5530 return (false); 5531 } else if (obj->tlsalign > tls_static_max_align) { 5532 tls_static_max_align = obj->tlsalign; 5533 } 5534 5535 tls_last_offset = off; 5536 tls_last_size = obj->tlssize; 5537 obj->tls_static = true; 5538 5539 return (true); 5540 } 5541 5542 void 5543 free_tls_offset(Obj_Entry *obj) 5544 { 5545 5546 /* 5547 * If we were the last thing to allocate out of the static TLS 5548 * block, we give our space back to the 'allocator'. This is a 5549 * simplistic workaround to allow libGL.so.1 to be loaded and 5550 * unloaded multiple times. 5551 */ 5552 size_t off = obj->tlsoffset; 5553 #ifdef TLS_VARIANT_I 5554 off += obj->tlssize; 5555 #endif 5556 if (off == tls_last_offset) { 5557 tls_last_offset -= obj->tlssize; 5558 tls_last_size = 0; 5559 } 5560 } 5561 5562 void * 5563 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 5564 { 5565 void *ret; 5566 RtldLockState lockstate; 5567 5568 wlock_acquire(rtld_bind_lock, &lockstate); 5569 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 5570 tcbsize, tcbalign); 5571 lock_release(rtld_bind_lock, &lockstate); 5572 return (ret); 5573 } 5574 5575 void 5576 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 5577 { 5578 RtldLockState lockstate; 5579 5580 wlock_acquire(rtld_bind_lock, &lockstate); 5581 free_tls(tcb, tcbsize, tcbalign); 5582 lock_release(rtld_bind_lock, &lockstate); 5583 } 5584 5585 static void 5586 object_add_name(Obj_Entry *obj, const char *name) 5587 { 5588 Name_Entry *entry; 5589 size_t len; 5590 5591 len = strlen(name); 5592 entry = malloc(sizeof(Name_Entry) + len); 5593 5594 if (entry != NULL) { 5595 strcpy(entry->name, name); 5596 STAILQ_INSERT_TAIL(&obj->names, entry, link); 5597 } 5598 } 5599 5600 static int 5601 object_match_name(const Obj_Entry *obj, const char *name) 5602 { 5603 Name_Entry *entry; 5604 5605 STAILQ_FOREACH(entry, &obj->names, link) { 5606 if (strcmp(name, entry->name) == 0) 5607 return (1); 5608 } 5609 return (0); 5610 } 5611 5612 static Obj_Entry * 5613 locate_dependency(const Obj_Entry *obj, const char *name) 5614 { 5615 const Objlist_Entry *entry; 5616 const Needed_Entry *needed; 5617 5618 STAILQ_FOREACH(entry, &list_main, link) { 5619 if (object_match_name(entry->obj, name)) 5620 return (entry->obj); 5621 } 5622 5623 for (needed = obj->needed; needed != NULL; needed = needed->next) { 5624 if (strcmp(obj->strtab + needed->name, name) == 0 || 5625 (needed->obj != NULL && object_match_name(needed->obj, name))) { 5626 /* 5627 * If there is DT_NEEDED for the name we are looking for, 5628 * we are all set. Note that object might not be found if 5629 * dependency was not loaded yet, so the function can 5630 * return NULL here. This is expected and handled 5631 * properly by the caller. 5632 */ 5633 return (needed->obj); 5634 } 5635 } 5636 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 5637 obj->path, name); 5638 rtld_die(); 5639 } 5640 5641 static int 5642 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 5643 const Elf_Vernaux *vna) 5644 { 5645 const Elf_Verdef *vd; 5646 const char *vername; 5647 5648 vername = refobj->strtab + vna->vna_name; 5649 vd = depobj->verdef; 5650 if (vd == NULL) { 5651 _rtld_error("%s: version %s required by %s not defined", 5652 depobj->path, vername, refobj->path); 5653 return (-1); 5654 } 5655 for (;;) { 5656 if (vd->vd_version != VER_DEF_CURRENT) { 5657 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5658 depobj->path, vd->vd_version); 5659 return (-1); 5660 } 5661 if (vna->vna_hash == vd->vd_hash) { 5662 const Elf_Verdaux *aux = (const Elf_Verdaux *) 5663 ((const char *)vd + vd->vd_aux); 5664 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 5665 return (0); 5666 } 5667 if (vd->vd_next == 0) 5668 break; 5669 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5670 } 5671 if (vna->vna_flags & VER_FLG_WEAK) 5672 return (0); 5673 _rtld_error("%s: version %s required by %s not found", 5674 depobj->path, vername, refobj->path); 5675 return (-1); 5676 } 5677 5678 static int 5679 rtld_verify_object_versions(Obj_Entry *obj) 5680 { 5681 const Elf_Verneed *vn; 5682 const Elf_Verdef *vd; 5683 const Elf_Verdaux *vda; 5684 const Elf_Vernaux *vna; 5685 const Obj_Entry *depobj; 5686 int maxvernum, vernum; 5687 5688 if (obj->ver_checked) 5689 return (0); 5690 obj->ver_checked = true; 5691 5692 maxvernum = 0; 5693 /* 5694 * Walk over defined and required version records and figure out 5695 * max index used by any of them. Do very basic sanity checking 5696 * while there. 5697 */ 5698 vn = obj->verneed; 5699 while (vn != NULL) { 5700 if (vn->vn_version != VER_NEED_CURRENT) { 5701 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 5702 obj->path, vn->vn_version); 5703 return (-1); 5704 } 5705 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5706 for (;;) { 5707 vernum = VER_NEED_IDX(vna->vna_other); 5708 if (vernum > maxvernum) 5709 maxvernum = vernum; 5710 if (vna->vna_next == 0) 5711 break; 5712 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5713 } 5714 if (vn->vn_next == 0) 5715 break; 5716 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5717 } 5718 5719 vd = obj->verdef; 5720 while (vd != NULL) { 5721 if (vd->vd_version != VER_DEF_CURRENT) { 5722 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5723 obj->path, vd->vd_version); 5724 return (-1); 5725 } 5726 vernum = VER_DEF_IDX(vd->vd_ndx); 5727 if (vernum > maxvernum) 5728 maxvernum = vernum; 5729 if (vd->vd_next == 0) 5730 break; 5731 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5732 } 5733 5734 if (maxvernum == 0) 5735 return (0); 5736 5737 /* 5738 * Store version information in array indexable by version index. 5739 * Verify that object version requirements are satisfied along the 5740 * way. 5741 */ 5742 obj->vernum = maxvernum + 1; 5743 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 5744 5745 vd = obj->verdef; 5746 while (vd != NULL) { 5747 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 5748 vernum = VER_DEF_IDX(vd->vd_ndx); 5749 assert(vernum <= maxvernum); 5750 vda = (const Elf_Verdaux *)((const char *)vd + vd->vd_aux); 5751 obj->vertab[vernum].hash = vd->vd_hash; 5752 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 5753 obj->vertab[vernum].file = NULL; 5754 obj->vertab[vernum].flags = 0; 5755 } 5756 if (vd->vd_next == 0) 5757 break; 5758 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5759 } 5760 5761 vn = obj->verneed; 5762 while (vn != NULL) { 5763 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 5764 if (depobj == NULL) 5765 return (-1); 5766 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5767 for (;;) { 5768 if (check_object_provided_version(obj, depobj, vna)) 5769 return (-1); 5770 vernum = VER_NEED_IDX(vna->vna_other); 5771 assert(vernum <= maxvernum); 5772 obj->vertab[vernum].hash = vna->vna_hash; 5773 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 5774 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 5775 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 5776 VER_INFO_HIDDEN : 0; 5777 if (vna->vna_next == 0) 5778 break; 5779 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5780 } 5781 if (vn->vn_next == 0) 5782 break; 5783 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5784 } 5785 return (0); 5786 } 5787 5788 static int 5789 rtld_verify_versions(const Objlist *objlist) 5790 { 5791 Objlist_Entry *entry; 5792 int rc; 5793 5794 rc = 0; 5795 STAILQ_FOREACH(entry, objlist, link) { 5796 /* 5797 * Skip dummy objects or objects that have their version requirements 5798 * already checked. 5799 */ 5800 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 5801 continue; 5802 if (rtld_verify_object_versions(entry->obj) == -1) { 5803 rc = -1; 5804 if (ld_tracing == NULL) 5805 break; 5806 } 5807 } 5808 if (rc == 0 || ld_tracing != NULL) 5809 rc = rtld_verify_object_versions(&obj_rtld); 5810 return (rc); 5811 } 5812 5813 const Ver_Entry * 5814 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 5815 { 5816 Elf_Versym vernum; 5817 5818 if (obj->vertab) { 5819 vernum = VER_NDX(obj->versyms[symnum]); 5820 if (vernum >= obj->vernum) { 5821 _rtld_error("%s: symbol %s has wrong verneed value %d", 5822 obj->path, obj->strtab + symnum, vernum); 5823 } else if (obj->vertab[vernum].hash != 0) { 5824 return (&obj->vertab[vernum]); 5825 } 5826 } 5827 return (NULL); 5828 } 5829 5830 int 5831 _rtld_get_stack_prot(void) 5832 { 5833 5834 return (stack_prot); 5835 } 5836 5837 int 5838 _rtld_is_dlopened(void *arg) 5839 { 5840 Obj_Entry *obj; 5841 RtldLockState lockstate; 5842 int res; 5843 5844 rlock_acquire(rtld_bind_lock, &lockstate); 5845 obj = dlcheck(arg); 5846 if (obj == NULL) 5847 obj = obj_from_addr(arg); 5848 if (obj == NULL) { 5849 _rtld_error("No shared object contains address"); 5850 lock_release(rtld_bind_lock, &lockstate); 5851 return (-1); 5852 } 5853 res = obj->dlopened ? 1 : 0; 5854 lock_release(rtld_bind_lock, &lockstate); 5855 return (res); 5856 } 5857 5858 static int 5859 obj_remap_relro(Obj_Entry *obj, int prot) 5860 { 5861 5862 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size, 5863 prot) == -1) { 5864 _rtld_error("%s: Cannot set relro protection to %#x: %s", 5865 obj->path, prot, rtld_strerror(errno)); 5866 return (-1); 5867 } 5868 return (0); 5869 } 5870 5871 static int 5872 obj_disable_relro(Obj_Entry *obj) 5873 { 5874 5875 return (obj_remap_relro(obj, PROT_READ | PROT_WRITE)); 5876 } 5877 5878 static int 5879 obj_enforce_relro(Obj_Entry *obj) 5880 { 5881 5882 return (obj_remap_relro(obj, PROT_READ)); 5883 } 5884 5885 static void 5886 map_stacks_exec(RtldLockState *lockstate) 5887 { 5888 void (*thr_map_stacks_exec)(void); 5889 5890 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5891 return; 5892 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5893 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5894 if (thr_map_stacks_exec != NULL) { 5895 stack_prot |= PROT_EXEC; 5896 thr_map_stacks_exec(); 5897 } 5898 } 5899 5900 static void 5901 distribute_static_tls(Objlist *list, RtldLockState *lockstate) 5902 { 5903 Objlist_Entry *elm; 5904 Obj_Entry *obj; 5905 void (*distrib)(size_t, void *, size_t, size_t); 5906 5907 distrib = (void (*)(size_t, void *, size_t, size_t))(uintptr_t) 5908 get_program_var_addr("__pthread_distribute_static_tls", lockstate); 5909 if (distrib == NULL) 5910 return; 5911 STAILQ_FOREACH(elm, list, link) { 5912 obj = elm->obj; 5913 if (obj->marker || !obj->tls_static || obj->static_tls_copied) 5914 continue; 5915 lock_release(rtld_bind_lock, lockstate); 5916 distrib(obj->tlsoffset, obj->tlsinit, obj->tlsinitsize, 5917 obj->tlssize); 5918 wlock_acquire(rtld_bind_lock, lockstate); 5919 obj->static_tls_copied = true; 5920 } 5921 } 5922 5923 void 5924 symlook_init(SymLook *dst, const char *name) 5925 { 5926 5927 bzero(dst, sizeof(*dst)); 5928 dst->name = name; 5929 dst->hash = elf_hash(name); 5930 dst->hash_gnu = gnu_hash(name); 5931 } 5932 5933 static void 5934 symlook_init_from_req(SymLook *dst, const SymLook *src) 5935 { 5936 5937 dst->name = src->name; 5938 dst->hash = src->hash; 5939 dst->hash_gnu = src->hash_gnu; 5940 dst->ventry = src->ventry; 5941 dst->flags = src->flags; 5942 dst->defobj_out = NULL; 5943 dst->sym_out = NULL; 5944 dst->lockstate = src->lockstate; 5945 } 5946 5947 static int 5948 open_binary_fd(const char *argv0, bool search_in_path, 5949 const char **binpath_res) 5950 { 5951 char *binpath, *pathenv, *pe, *res1; 5952 const char *res; 5953 int fd; 5954 5955 binpath = NULL; 5956 res = NULL; 5957 if (search_in_path && strchr(argv0, '/') == NULL) { 5958 binpath = xmalloc(PATH_MAX); 5959 pathenv = getenv("PATH"); 5960 if (pathenv == NULL) { 5961 _rtld_error("-p and no PATH environment variable"); 5962 rtld_die(); 5963 } 5964 pathenv = strdup(pathenv); 5965 if (pathenv == NULL) { 5966 _rtld_error("Cannot allocate memory"); 5967 rtld_die(); 5968 } 5969 fd = -1; 5970 errno = ENOENT; 5971 while ((pe = strsep(&pathenv, ":")) != NULL) { 5972 if (strlcpy(binpath, pe, PATH_MAX) >= PATH_MAX) 5973 continue; 5974 if (binpath[0] != '\0' && 5975 strlcat(binpath, "/", PATH_MAX) >= PATH_MAX) 5976 continue; 5977 if (strlcat(binpath, argv0, PATH_MAX) >= PATH_MAX) 5978 continue; 5979 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY); 5980 if (fd != -1 || errno != ENOENT) { 5981 res = binpath; 5982 break; 5983 } 5984 } 5985 free(pathenv); 5986 } else { 5987 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY); 5988 res = argv0; 5989 } 5990 5991 if (fd == -1) { 5992 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno)); 5993 rtld_die(); 5994 } 5995 if (res != NULL && res[0] != '/') { 5996 res1 = xmalloc(PATH_MAX); 5997 if (realpath(res, res1) != NULL) { 5998 if (res != argv0) 5999 free(__DECONST(char *, res)); 6000 res = res1; 6001 } else { 6002 free(res1); 6003 } 6004 } 6005 *binpath_res = res; 6006 return (fd); 6007 } 6008 6009 /* 6010 * Parse a set of command-line arguments. 6011 */ 6012 static int 6013 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp, 6014 const char **argv0, bool *dir_ignore) 6015 { 6016 const char *arg; 6017 char machine[64]; 6018 size_t sz; 6019 int arglen, fd, i, j, mib[2]; 6020 char opt; 6021 bool seen_b, seen_f; 6022 6023 dbg("Parsing command-line arguments"); 6024 *use_pathp = false; 6025 *fdp = -1; 6026 *dir_ignore = false; 6027 seen_b = seen_f = false; 6028 6029 for (i = 1; i < argc; i++ ) { 6030 arg = argv[i]; 6031 dbg("argv[%d]: '%s'", i, arg); 6032 6033 /* 6034 * rtld arguments end with an explicit "--" or with the first 6035 * non-prefixed argument. 6036 */ 6037 if (strcmp(arg, "--") == 0) { 6038 i++; 6039 break; 6040 } 6041 if (arg[0] != '-') 6042 break; 6043 6044 /* 6045 * All other arguments are single-character options that can 6046 * be combined, so we need to search through `arg` for them. 6047 */ 6048 arglen = strlen(arg); 6049 for (j = 1; j < arglen; j++) { 6050 opt = arg[j]; 6051 if (opt == 'h') { 6052 print_usage(argv[0]); 6053 _exit(0); 6054 } else if (opt == 'b') { 6055 if (seen_f) { 6056 _rtld_error("Both -b and -f specified"); 6057 rtld_die(); 6058 } 6059 if (j != arglen - 1) { 6060 _rtld_error("Invalid options: %s", arg); 6061 rtld_die(); 6062 } 6063 i++; 6064 *argv0 = argv[i]; 6065 seen_b = true; 6066 break; 6067 } else if (opt == 'd') { 6068 *dir_ignore = true; 6069 } else if (opt == 'f') { 6070 if (seen_b) { 6071 _rtld_error("Both -b and -f specified"); 6072 rtld_die(); 6073 } 6074 6075 /* 6076 * -f XX can be used to specify a 6077 * descriptor for the binary named at 6078 * the command line (i.e., the later 6079 * argument will specify the process 6080 * name but the descriptor is what 6081 * will actually be executed). 6082 * 6083 * -f must be the last option in the 6084 * group, e.g., -abcf <fd>. 6085 */ 6086 if (j != arglen - 1) { 6087 _rtld_error("Invalid options: %s", arg); 6088 rtld_die(); 6089 } 6090 i++; 6091 fd = parse_integer(argv[i]); 6092 if (fd == -1) { 6093 _rtld_error( 6094 "Invalid file descriptor: '%s'", 6095 argv[i]); 6096 rtld_die(); 6097 } 6098 *fdp = fd; 6099 seen_f = true; 6100 break; 6101 } else if (opt == 'p') { 6102 *use_pathp = true; 6103 } else if (opt == 'u') { 6104 trust = false; 6105 } else if (opt == 'v') { 6106 machine[0] = '\0'; 6107 mib[0] = CTL_HW; 6108 mib[1] = HW_MACHINE; 6109 sz = sizeof(machine); 6110 sysctl(mib, nitems(mib), machine, &sz, NULL, 0); 6111 ld_elf_hints_path = ld_get_env_var( 6112 LD_ELF_HINTS_PATH); 6113 set_ld_elf_hints_path(); 6114 rtld_printf( 6115 "FreeBSD ld-elf.so.1 %s\n" 6116 "FreeBSD_version %d\n" 6117 "Default lib path %s\n" 6118 "Hints lib path %s\n" 6119 "Env prefix %s\n" 6120 "Default hint file %s\n" 6121 "Hint file %s\n" 6122 "libmap file %s\n" 6123 "Optional static TLS size %zd bytes\n", 6124 machine, 6125 __FreeBSD_version, ld_standard_library_path, 6126 gethints(false), 6127 ld_env_prefix, ld_elf_hints_default, 6128 ld_elf_hints_path, 6129 ld_path_libmap_conf, 6130 ld_static_tls_extra); 6131 _exit(0); 6132 } else { 6133 _rtld_error("Invalid argument: '%s'", arg); 6134 print_usage(argv[0]); 6135 rtld_die(); 6136 } 6137 } 6138 } 6139 6140 if (!seen_b) 6141 *argv0 = argv[i]; 6142 return (i); 6143 } 6144 6145 /* 6146 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 6147 */ 6148 static int 6149 parse_integer(const char *str) 6150 { 6151 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 6152 const char *orig; 6153 int n; 6154 char c; 6155 6156 orig = str; 6157 n = 0; 6158 for (c = *str; c != '\0'; c = *++str) { 6159 if (c < '0' || c > '9') 6160 return (-1); 6161 6162 n *= RADIX; 6163 n += c - '0'; 6164 } 6165 6166 /* Make sure we actually parsed something. */ 6167 if (str == orig) 6168 return (-1); 6169 return (n); 6170 } 6171 6172 static void 6173 print_usage(const char *argv0) 6174 { 6175 6176 rtld_printf( 6177 "Usage: %s [-h] [-b <exe>] [-d] [-f <FD>] [-p] [--] <binary> [<args>]\n" 6178 "\n" 6179 "Options:\n" 6180 " -h Display this help message\n" 6181 " -b <exe> Execute <exe> instead of <binary>, arg0 is <binary>\n" 6182 " -d Ignore lack of exec permissions for the binary\n" 6183 " -f <FD> Execute <FD> instead of searching for <binary>\n" 6184 " -p Search in PATH for named binary\n" 6185 " -u Ignore LD_ environment variables\n" 6186 " -v Display identification information\n" 6187 " -- End of RTLD options\n" 6188 " <binary> Name of process to execute\n" 6189 " <args> Arguments to the executed process\n", argv0); 6190 } 6191 6192 #define AUXFMT(at, xfmt) [at] = { .name = #at, .fmt = xfmt } 6193 static const struct auxfmt { 6194 const char *name; 6195 const char *fmt; 6196 } auxfmts[] = { 6197 AUXFMT(AT_NULL, NULL), 6198 AUXFMT(AT_IGNORE, NULL), 6199 AUXFMT(AT_EXECFD, "%ld"), 6200 AUXFMT(AT_PHDR, "%p"), 6201 AUXFMT(AT_PHENT, "%lu"), 6202 AUXFMT(AT_PHNUM, "%lu"), 6203 AUXFMT(AT_PAGESZ, "%lu"), 6204 AUXFMT(AT_BASE, "%#lx"), 6205 AUXFMT(AT_FLAGS, "%#lx"), 6206 AUXFMT(AT_ENTRY, "%p"), 6207 AUXFMT(AT_NOTELF, NULL), 6208 AUXFMT(AT_UID, "%ld"), 6209 AUXFMT(AT_EUID, "%ld"), 6210 AUXFMT(AT_GID, "%ld"), 6211 AUXFMT(AT_EGID, "%ld"), 6212 AUXFMT(AT_EXECPATH, "%s"), 6213 AUXFMT(AT_CANARY, "%p"), 6214 AUXFMT(AT_CANARYLEN, "%lu"), 6215 AUXFMT(AT_OSRELDATE, "%lu"), 6216 AUXFMT(AT_NCPUS, "%lu"), 6217 AUXFMT(AT_PAGESIZES, "%p"), 6218 AUXFMT(AT_PAGESIZESLEN, "%lu"), 6219 AUXFMT(AT_TIMEKEEP, "%p"), 6220 AUXFMT(AT_STACKPROT, "%#lx"), 6221 AUXFMT(AT_EHDRFLAGS, "%#lx"), 6222 AUXFMT(AT_HWCAP, "%#lx"), 6223 AUXFMT(AT_HWCAP2, "%#lx"), 6224 AUXFMT(AT_BSDFLAGS, "%#lx"), 6225 AUXFMT(AT_ARGC, "%lu"), 6226 AUXFMT(AT_ARGV, "%p"), 6227 AUXFMT(AT_ENVC, "%p"), 6228 AUXFMT(AT_ENVV, "%p"), 6229 AUXFMT(AT_PS_STRINGS, "%p"), 6230 AUXFMT(AT_FXRNG, "%p"), 6231 AUXFMT(AT_KPRELOAD, "%p"), 6232 AUXFMT(AT_USRSTACKBASE, "%#lx"), 6233 AUXFMT(AT_USRSTACKLIM, "%#lx"), 6234 }; 6235 6236 static bool 6237 is_ptr_fmt(const char *fmt) 6238 { 6239 char last; 6240 6241 last = fmt[strlen(fmt) - 1]; 6242 return (last == 'p' || last == 's'); 6243 } 6244 6245 static void 6246 dump_auxv(Elf_Auxinfo **aux_info) 6247 { 6248 Elf_Auxinfo *auxp; 6249 const struct auxfmt *fmt; 6250 int i; 6251 6252 for (i = 0; i < AT_COUNT; i++) { 6253 auxp = aux_info[i]; 6254 if (auxp == NULL) 6255 continue; 6256 fmt = &auxfmts[i]; 6257 if (fmt->fmt == NULL) 6258 continue; 6259 rtld_fdprintf(STDOUT_FILENO, "%s:\t", fmt->name); 6260 if (is_ptr_fmt(fmt->fmt)) { 6261 rtld_fdprintfx(STDOUT_FILENO, fmt->fmt, 6262 auxp->a_un.a_ptr); 6263 } else { 6264 rtld_fdprintfx(STDOUT_FILENO, fmt->fmt, 6265 auxp->a_un.a_val); 6266 } 6267 rtld_fdprintf(STDOUT_FILENO, "\n"); 6268 } 6269 } 6270 6271 /* 6272 * Overrides for libc_pic-provided functions. 6273 */ 6274 6275 int 6276 __getosreldate(void) 6277 { 6278 size_t len; 6279 int oid[2]; 6280 int error, osrel; 6281 6282 if (osreldate != 0) 6283 return (osreldate); 6284 6285 oid[0] = CTL_KERN; 6286 oid[1] = KERN_OSRELDATE; 6287 osrel = 0; 6288 len = sizeof(osrel); 6289 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 6290 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 6291 osreldate = osrel; 6292 return (osreldate); 6293 } 6294 const char * 6295 rtld_strerror(int errnum) 6296 { 6297 6298 if (errnum < 0 || errnum >= sys_nerr) 6299 return ("Unknown error"); 6300 return (sys_errlist[errnum]); 6301 } 6302 6303 char * 6304 getenv(const char *name) 6305 { 6306 return (__DECONST(char *, rtld_get_env_val(environ, name, 6307 strlen(name)))); 6308 } 6309 6310 /* malloc */ 6311 void * 6312 malloc(size_t nbytes) 6313 { 6314 6315 return (__crt_malloc(nbytes)); 6316 } 6317 6318 void * 6319 calloc(size_t num, size_t size) 6320 { 6321 6322 return (__crt_calloc(num, size)); 6323 } 6324 6325 void 6326 free(void *cp) 6327 { 6328 6329 __crt_free(cp); 6330 } 6331 6332 void * 6333 realloc(void *cp, size_t nbytes) 6334 { 6335 6336 return (__crt_realloc(cp, nbytes)); 6337 } 6338 6339 extern int _rtld_version__FreeBSD_version __exported; 6340 int _rtld_version__FreeBSD_version = __FreeBSD_version; 6341 6342 extern char _rtld_version_laddr_offset __exported; 6343 char _rtld_version_laddr_offset; 6344 6345 extern char _rtld_version_dlpi_tls_data __exported; 6346 char _rtld_version_dlpi_tls_data; 6347