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 /* Convert between native byte order and forced little resp. big endian. */ 2054 #define COND_SWAP(n) (is_le ? le32toh(n) : be32toh(n)) 2055 2056 /* 2057 * Return the search path from the ldconfig hints file, reading it if 2058 * necessary. If nostdlib is true, then the default search paths are 2059 * not added to result. 2060 * 2061 * Returns NULL if there are problems with the hints file, 2062 * or if the search path there is empty. 2063 */ 2064 static const char * 2065 gethints(bool nostdlib) 2066 { 2067 static char *filtered_path; 2068 static const char *hints; 2069 static struct elfhints_hdr hdr; 2070 struct fill_search_info_args sargs, hargs; 2071 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 2072 struct dl_serpath *SLPpath, *hintpath; 2073 char *p; 2074 struct stat hint_stat; 2075 unsigned int SLPndx, hintndx, fndx, fcount; 2076 int fd; 2077 size_t flen; 2078 uint32_t dl; 2079 uint32_t magic; /* Magic number */ 2080 uint32_t version; /* File version (1) */ 2081 uint32_t strtab; /* Offset of string table in file */ 2082 uint32_t dirlist; /* Offset of directory list in string table */ 2083 uint32_t dirlistlen; /* strlen(dirlist) */ 2084 bool is_le; 2085 bool skip; 2086 2087 /* First call, read the hints file */ 2088 if (hints == NULL) { 2089 /* Keep from trying again in case the hints file is bad. */ 2090 hints = ""; 2091 2092 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) { 2093 dbg("failed to open hints file \"%s\"", ld_elf_hints_path); 2094 return (NULL); 2095 } 2096 2097 /* 2098 * Check of hdr.dirlistlen value against type limit 2099 * intends to pacify static analyzers. Further 2100 * paranoia leads to checks that dirlist is fully 2101 * contained in the file range. 2102 */ 2103 if (read(fd, &hdr, sizeof hdr) != sizeof hdr) { 2104 dbg("failed to read %lu bytes from hints file \"%s\"", 2105 (u_long)sizeof hdr, ld_elf_hints_path); 2106 cleanup1: 2107 close(fd); 2108 hdr.dirlistlen = 0; 2109 return (NULL); 2110 } 2111 is_le = /*le32toh(1) == 1 || */ hdr.magic == ELFHINTS_MAGIC; 2112 dbg("host byte-order: %s-endian", le32toh(1) == 1 ? "little" : "big"); 2113 dbg("hints file byte-order: %s-endian", is_le ? "little" : "big"); 2114 dbg("verify swap macros: le32toh(0x12345678) == %#010x, " 2115 "be32toh(0x12345678) == %#010x", 2116 le32toh(0x12345678), be32toh(0x12345678)); 2117 magic = COND_SWAP(hdr.magic); 2118 version = COND_SWAP(hdr.version); 2119 strtab = COND_SWAP(hdr.strtab); 2120 dirlist = COND_SWAP(hdr.dirlist); 2121 dirlistlen = COND_SWAP(hdr.dirlistlen); 2122 if (magic != ELFHINTS_MAGIC) { 2123 dbg("invalid magic number %#08x (expected: %#08x)", 2124 magic, ELFHINTS_MAGIC); 2125 goto cleanup1; 2126 } 2127 if (version != 1) { 2128 dbg("hints file version %d (expected: 1)", version); 2129 goto cleanup1; 2130 } 2131 if (dirlistlen > UINT_MAX / 2) { 2132 dbg("directory list is to long: %d > %d", 2133 dirlistlen, UINT_MAX / 2); 2134 goto cleanup1; 2135 } 2136 if (fstat(fd, &hint_stat) == -1) { 2137 dbg("failed to find length of hints file \"%s\"", 2138 ld_elf_hints_path); 2139 goto cleanup1; 2140 } 2141 dl = strtab; 2142 if (dl + dirlist < dl) { 2143 dbg("invalid string table position %d", dl); 2144 goto cleanup1; 2145 } 2146 dl += dirlist; 2147 if (dl + dirlistlen < dl) { 2148 dbg("invalid directory list offset %d", dirlist); 2149 goto cleanup1; 2150 } 2151 dl += dirlistlen; 2152 if (dl > hint_stat.st_size) { 2153 dbg("hints file \"%s\" is truncated (%d vs. %jd bytes)", 2154 ld_elf_hints_path, dl, (uintmax_t)hint_stat.st_size); 2155 goto cleanup1; 2156 } 2157 p = xmalloc(dirlistlen + 1); 2158 if (pread(fd, p, dirlistlen + 1, 2159 strtab + dirlist) != (ssize_t)dirlistlen + 1 || 2160 p[dirlistlen] != '\0') { 2161 free(p); 2162 dbg("failed to read %d bytes starting at %d from hints file \"%s\"", 2163 dirlistlen + 1, strtab + dirlist, ld_elf_hints_path); 2164 goto cleanup1; 2165 } 2166 hints = p; 2167 close(fd); 2168 } 2169 2170 /* 2171 * If caller agreed to receive list which includes the default 2172 * paths, we are done. Otherwise, if we still did not 2173 * calculated filtered result, do it now. 2174 */ 2175 if (!nostdlib) 2176 return (hints[0] != '\0' ? hints : NULL); 2177 if (filtered_path != NULL) 2178 goto filt_ret; 2179 2180 /* 2181 * Obtain the list of all configured search paths, and the 2182 * list of the default paths. 2183 * 2184 * First estimate the size of the results. 2185 */ 2186 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2187 smeta.dls_cnt = 0; 2188 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2189 hmeta.dls_cnt = 0; 2190 2191 sargs.request = RTLD_DI_SERINFOSIZE; 2192 sargs.serinfo = &smeta; 2193 hargs.request = RTLD_DI_SERINFOSIZE; 2194 hargs.serinfo = &hmeta; 2195 2196 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 2197 &sargs); 2198 path_enumerate(hints, fill_search_info, NULL, &hargs); 2199 2200 SLPinfo = xmalloc(smeta.dls_size); 2201 hintinfo = xmalloc(hmeta.dls_size); 2202 2203 /* 2204 * Next fetch both sets of paths. 2205 */ 2206 sargs.request = RTLD_DI_SERINFO; 2207 sargs.serinfo = SLPinfo; 2208 sargs.serpath = &SLPinfo->dls_serpath[0]; 2209 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 2210 2211 hargs.request = RTLD_DI_SERINFO; 2212 hargs.serinfo = hintinfo; 2213 hargs.serpath = &hintinfo->dls_serpath[0]; 2214 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 2215 2216 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 2217 &sargs); 2218 path_enumerate(hints, fill_search_info, NULL, &hargs); 2219 2220 /* 2221 * Now calculate the difference between two sets, by excluding 2222 * standard paths from the full set. 2223 */ 2224 fndx = 0; 2225 fcount = 0; 2226 filtered_path = xmalloc(dirlistlen + 1); 2227 hintpath = &hintinfo->dls_serpath[0]; 2228 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 2229 skip = false; 2230 SLPpath = &SLPinfo->dls_serpath[0]; 2231 /* 2232 * Check each standard path against current. 2233 */ 2234 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 2235 /* matched, skip the path */ 2236 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 2237 skip = true; 2238 break; 2239 } 2240 } 2241 if (skip) 2242 continue; 2243 /* 2244 * Not matched against any standard path, add the path 2245 * to result. Separate consequtive paths with ':'. 2246 */ 2247 if (fcount > 0) { 2248 filtered_path[fndx] = ':'; 2249 fndx++; 2250 } 2251 fcount++; 2252 flen = strlen(hintpath->dls_name); 2253 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 2254 fndx += flen; 2255 } 2256 filtered_path[fndx] = '\0'; 2257 2258 free(SLPinfo); 2259 free(hintinfo); 2260 2261 filt_ret: 2262 return (filtered_path[0] != '\0' ? filtered_path : NULL); 2263 } 2264 2265 static void 2266 init_dag(Obj_Entry *root) 2267 { 2268 const Needed_Entry *needed; 2269 const Objlist_Entry *elm; 2270 DoneList donelist; 2271 2272 if (root->dag_inited) 2273 return; 2274 donelist_init(&donelist); 2275 2276 /* Root object belongs to own DAG. */ 2277 objlist_push_tail(&root->dldags, root); 2278 objlist_push_tail(&root->dagmembers, root); 2279 donelist_check(&donelist, root); 2280 2281 /* 2282 * Add dependencies of root object to DAG in breadth order 2283 * by exploiting the fact that each new object get added 2284 * to the tail of the dagmembers list. 2285 */ 2286 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2287 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 2288 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 2289 continue; 2290 objlist_push_tail(&needed->obj->dldags, root); 2291 objlist_push_tail(&root->dagmembers, needed->obj); 2292 } 2293 } 2294 root->dag_inited = true; 2295 } 2296 2297 static void 2298 init_marker(Obj_Entry *marker) 2299 { 2300 2301 bzero(marker, sizeof(*marker)); 2302 marker->marker = true; 2303 } 2304 2305 Obj_Entry * 2306 globallist_curr(const Obj_Entry *obj) 2307 { 2308 2309 for (;;) { 2310 if (obj == NULL) 2311 return (NULL); 2312 if (!obj->marker) 2313 return (__DECONST(Obj_Entry *, obj)); 2314 obj = TAILQ_PREV(obj, obj_entry_q, next); 2315 } 2316 } 2317 2318 Obj_Entry * 2319 globallist_next(const Obj_Entry *obj) 2320 { 2321 2322 for (;;) { 2323 obj = TAILQ_NEXT(obj, next); 2324 if (obj == NULL) 2325 return (NULL); 2326 if (!obj->marker) 2327 return (__DECONST(Obj_Entry *, obj)); 2328 } 2329 } 2330 2331 /* Prevent the object from being unmapped while the bind lock is dropped. */ 2332 static void 2333 hold_object(Obj_Entry *obj) 2334 { 2335 2336 obj->holdcount++; 2337 } 2338 2339 static void 2340 unhold_object(Obj_Entry *obj) 2341 { 2342 2343 assert(obj->holdcount > 0); 2344 if (--obj->holdcount == 0 && obj->unholdfree) 2345 release_object(obj); 2346 } 2347 2348 static void 2349 process_z(Obj_Entry *root) 2350 { 2351 const Objlist_Entry *elm; 2352 Obj_Entry *obj; 2353 2354 /* 2355 * Walk over object DAG and process every dependent object 2356 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 2357 * to grow their own DAG. 2358 * 2359 * For DF_1_GLOBAL, DAG is required for symbol lookups in 2360 * symlook_global() to work. 2361 * 2362 * For DF_1_NODELETE, the DAG should have its reference upped. 2363 */ 2364 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2365 obj = elm->obj; 2366 if (obj == NULL) 2367 continue; 2368 if (obj->z_nodelete && !obj->ref_nodel) { 2369 dbg("obj %s -z nodelete", obj->path); 2370 init_dag(obj); 2371 ref_dag(obj); 2372 obj->ref_nodel = true; 2373 } 2374 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 2375 dbg("obj %s -z global", obj->path); 2376 objlist_push_tail(&list_global, obj); 2377 init_dag(obj); 2378 } 2379 } 2380 } 2381 2382 static void 2383 parse_rtld_phdr(Obj_Entry *obj) 2384 { 2385 const Elf_Phdr *ph; 2386 Elf_Addr note_start, note_end; 2387 2388 obj->stack_flags = PF_X | PF_R | PF_W; 2389 for (ph = obj->phdr; (const char *)ph < (const char *)obj->phdr + 2390 obj->phsize; ph++) { 2391 switch (ph->p_type) { 2392 case PT_GNU_STACK: 2393 obj->stack_flags = ph->p_flags; 2394 break; 2395 case PT_GNU_RELRO: 2396 obj->relro_page = obj->relocbase + 2397 rtld_trunc_page(ph->p_vaddr); 2398 obj->relro_size = rtld_round_page(ph->p_memsz); 2399 break; 2400 case PT_NOTE: 2401 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 2402 note_end = note_start + ph->p_filesz; 2403 digest_notes(obj, note_start, note_end); 2404 break; 2405 } 2406 } 2407 } 2408 2409 /* 2410 * Initialize the dynamic linker. The argument is the address at which 2411 * the dynamic linker has been mapped into memory. The primary task of 2412 * this function is to relocate the dynamic linker. 2413 */ 2414 static void 2415 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 2416 { 2417 Obj_Entry objtmp; /* Temporary rtld object */ 2418 const Elf_Ehdr *ehdr; 2419 const Elf_Dyn *dyn_rpath; 2420 const Elf_Dyn *dyn_soname; 2421 const Elf_Dyn *dyn_runpath; 2422 2423 #ifdef RTLD_INIT_PAGESIZES_EARLY 2424 /* The page size is required by the dynamic memory allocator. */ 2425 init_pagesizes(aux_info); 2426 #endif 2427 2428 /* 2429 * Conjure up an Obj_Entry structure for the dynamic linker. 2430 * 2431 * The "path" member can't be initialized yet because string constants 2432 * cannot yet be accessed. Below we will set it correctly. 2433 */ 2434 memset(&objtmp, 0, sizeof(objtmp)); 2435 objtmp.path = NULL; 2436 objtmp.rtld = true; 2437 objtmp.mapbase = mapbase; 2438 #ifdef PIC 2439 objtmp.relocbase = mapbase; 2440 #endif 2441 2442 objtmp.dynamic = rtld_dynamic(&objtmp); 2443 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 2444 assert(objtmp.needed == NULL); 2445 assert(!objtmp.textrel); 2446 /* 2447 * Temporarily put the dynamic linker entry into the object list, so 2448 * that symbols can be found. 2449 */ 2450 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 2451 2452 ehdr = (Elf_Ehdr *)mapbase; 2453 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 2454 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 2455 2456 /* Initialize the object list. */ 2457 TAILQ_INIT(&obj_list); 2458 2459 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 2460 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 2461 2462 #ifndef RTLD_INIT_PAGESIZES_EARLY 2463 /* The page size is required by the dynamic memory allocator. */ 2464 init_pagesizes(aux_info); 2465 #endif 2466 2467 if (aux_info[AT_OSRELDATE] != NULL) 2468 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 2469 2470 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 2471 2472 /* Replace the path with a dynamically allocated copy. */ 2473 obj_rtld.path = xstrdup(ld_path_rtld); 2474 2475 parse_rtld_phdr(&obj_rtld); 2476 if (obj_enforce_relro(&obj_rtld) == -1) 2477 rtld_die(); 2478 2479 r_debug.r_version = R_DEBUG_VERSION; 2480 r_debug.r_brk = r_debug_state; 2481 r_debug.r_state = RT_CONSISTENT; 2482 r_debug.r_ldbase = obj_rtld.relocbase; 2483 } 2484 2485 /* 2486 * Retrieve the array of supported page sizes. The kernel provides the page 2487 * sizes in increasing order. 2488 */ 2489 static void 2490 init_pagesizes(Elf_Auxinfo **aux_info) 2491 { 2492 static size_t psa[MAXPAGESIZES]; 2493 int mib[2]; 2494 size_t len, size; 2495 2496 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 2497 NULL) { 2498 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 2499 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 2500 } else { 2501 len = 2; 2502 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 2503 size = sizeof(psa); 2504 else { 2505 /* As a fallback, retrieve the base page size. */ 2506 size = sizeof(psa[0]); 2507 if (aux_info[AT_PAGESZ] != NULL) { 2508 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 2509 goto psa_filled; 2510 } else { 2511 mib[0] = CTL_HW; 2512 mib[1] = HW_PAGESIZE; 2513 len = 2; 2514 } 2515 } 2516 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 2517 _rtld_error("sysctl for hw.pagesize(s) failed"); 2518 rtld_die(); 2519 } 2520 psa_filled: 2521 pagesizes = psa; 2522 } 2523 npagesizes = size / sizeof(pagesizes[0]); 2524 /* Discard any invalid entries at the end of the array. */ 2525 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 2526 npagesizes--; 2527 2528 page_size = pagesizes[0]; 2529 } 2530 2531 /* 2532 * Add the init functions from a needed object list (and its recursive 2533 * needed objects) to "list". This is not used directly; it is a helper 2534 * function for initlist_add_objects(). The write lock must be held 2535 * when this function is called. 2536 */ 2537 static void 2538 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 2539 { 2540 /* Recursively process the successor needed objects. */ 2541 if (needed->next != NULL) 2542 initlist_add_neededs(needed->next, list); 2543 2544 /* Process the current needed object. */ 2545 if (needed->obj != NULL) 2546 initlist_add_objects(needed->obj, needed->obj, list); 2547 } 2548 2549 /* 2550 * Scan all of the DAGs rooted in the range of objects from "obj" to 2551 * "tail" and add their init functions to "list". This recurses over 2552 * the DAGs and ensure the proper init ordering such that each object's 2553 * needed libraries are initialized before the object itself. At the 2554 * same time, this function adds the objects to the global finalization 2555 * list "list_fini" in the opposite order. The write lock must be 2556 * held when this function is called. 2557 */ 2558 static void 2559 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2560 { 2561 Obj_Entry *nobj; 2562 2563 if (obj->init_scanned || obj->init_done) 2564 return; 2565 obj->init_scanned = true; 2566 2567 /* Recursively process the successor objects. */ 2568 nobj = globallist_next(obj); 2569 if (nobj != NULL && obj != tail) 2570 initlist_add_objects(nobj, tail, list); 2571 2572 /* Recursively process the needed objects. */ 2573 if (obj->needed != NULL) 2574 initlist_add_neededs(obj->needed, list); 2575 if (obj->needed_filtees != NULL) 2576 initlist_add_neededs(obj->needed_filtees, list); 2577 if (obj->needed_aux_filtees != NULL) 2578 initlist_add_neededs(obj->needed_aux_filtees, list); 2579 2580 /* Add the object to the init list. */ 2581 objlist_push_tail(list, obj); 2582 2583 /* Add the object to the global fini list in the reverse order. */ 2584 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2585 && !obj->on_fini_list) { 2586 objlist_push_head(&list_fini, obj); 2587 obj->on_fini_list = true; 2588 } 2589 } 2590 2591 static void 2592 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate) 2593 { 2594 Needed_Entry *needed, *needed1; 2595 2596 for (needed = n; needed != NULL; needed = needed->next) { 2597 if (needed->obj != NULL) { 2598 dlclose_locked(needed->obj, lockstate); 2599 needed->obj = NULL; 2600 } 2601 } 2602 for (needed = n; needed != NULL; needed = needed1) { 2603 needed1 = needed->next; 2604 free(needed); 2605 } 2606 } 2607 2608 static void 2609 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate) 2610 { 2611 2612 free_needed_filtees(obj->needed_filtees, lockstate); 2613 obj->needed_filtees = NULL; 2614 free_needed_filtees(obj->needed_aux_filtees, lockstate); 2615 obj->needed_aux_filtees = NULL; 2616 obj->filtees_loaded = false; 2617 } 2618 2619 static void 2620 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2621 RtldLockState *lockstate) 2622 { 2623 2624 for (; needed != NULL; needed = needed->next) { 2625 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2626 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2627 RTLD_LOCAL, lockstate); 2628 } 2629 } 2630 2631 static void 2632 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2633 { 2634 if (obj->filtees_loaded || obj->filtees_loading) 2635 return; 2636 lock_restart_for_upgrade(lockstate); 2637 obj->filtees_loading = true; 2638 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2639 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2640 obj->filtees_loaded = true; 2641 obj->filtees_loading = false; 2642 } 2643 2644 static int 2645 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2646 { 2647 Obj_Entry *obj1; 2648 2649 for (; needed != NULL; needed = needed->next) { 2650 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2651 flags & ~RTLD_LO_NOLOAD); 2652 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2653 return (-1); 2654 } 2655 return (0); 2656 } 2657 2658 /* 2659 * Given a shared object, traverse its list of needed objects, and load 2660 * each of them. Returns 0 on success. Generates an error message and 2661 * returns -1 on failure. 2662 */ 2663 static int 2664 load_needed_objects(Obj_Entry *first, int flags) 2665 { 2666 Obj_Entry *obj; 2667 2668 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2669 if (obj->marker) 2670 continue; 2671 if (process_needed(obj, obj->needed, flags) == -1) 2672 return (-1); 2673 } 2674 return (0); 2675 } 2676 2677 static int 2678 load_preload_objects(const char *penv, bool isfd) 2679 { 2680 Obj_Entry *obj; 2681 const char *name; 2682 size_t len; 2683 char savech, *p, *psave; 2684 int fd; 2685 static const char delim[] = " \t:;"; 2686 2687 if (penv == NULL) 2688 return (0); 2689 2690 p = psave = xstrdup(penv); 2691 p += strspn(p, delim); 2692 while (*p != '\0') { 2693 len = strcspn(p, delim); 2694 2695 savech = p[len]; 2696 p[len] = '\0'; 2697 if (isfd) { 2698 name = NULL; 2699 fd = parse_integer(p); 2700 if (fd == -1) { 2701 free(psave); 2702 return (-1); 2703 } 2704 } else { 2705 name = p; 2706 fd = -1; 2707 } 2708 2709 obj = load_object(name, fd, NULL, 0); 2710 if (obj == NULL) { 2711 free(psave); 2712 return (-1); /* XXX - cleanup */ 2713 } 2714 obj->z_interpose = true; 2715 p[len] = savech; 2716 p += len; 2717 p += strspn(p, delim); 2718 } 2719 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2720 2721 free(psave); 2722 return (0); 2723 } 2724 2725 static const char * 2726 printable_path(const char *path) 2727 { 2728 2729 return (path == NULL ? "<unknown>" : path); 2730 } 2731 2732 /* 2733 * Load a shared object into memory, if it is not already loaded. The 2734 * object may be specified by name or by user-supplied file descriptor 2735 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2736 * duplicate is. 2737 * 2738 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2739 * on failure. 2740 */ 2741 static Obj_Entry * 2742 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2743 { 2744 Obj_Entry *obj; 2745 int fd; 2746 struct stat sb; 2747 char *path; 2748 2749 fd = -1; 2750 if (name != NULL) { 2751 TAILQ_FOREACH(obj, &obj_list, next) { 2752 if (obj->marker || obj->doomed) 2753 continue; 2754 if (object_match_name(obj, name)) 2755 return (obj); 2756 } 2757 2758 path = find_library(name, refobj, &fd); 2759 if (path == NULL) 2760 return (NULL); 2761 } else 2762 path = NULL; 2763 2764 if (fd >= 0) { 2765 /* 2766 * search_library_pathfds() opens a fresh file descriptor for the 2767 * library, so there is no need to dup(). 2768 */ 2769 } else if (fd_u == -1) { 2770 /* 2771 * If we didn't find a match by pathname, or the name is not 2772 * supplied, open the file and check again by device and inode. 2773 * This avoids false mismatches caused by multiple links or ".." 2774 * in pathnames. 2775 * 2776 * To avoid a race, we open the file and use fstat() rather than 2777 * using stat(). 2778 */ 2779 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { 2780 _rtld_error("Cannot open \"%s\"", path); 2781 free(path); 2782 return (NULL); 2783 } 2784 } else { 2785 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2786 if (fd == -1) { 2787 _rtld_error("Cannot dup fd"); 2788 free(path); 2789 return (NULL); 2790 } 2791 } 2792 if (fstat(fd, &sb) == -1) { 2793 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2794 close(fd); 2795 free(path); 2796 return (NULL); 2797 } 2798 TAILQ_FOREACH(obj, &obj_list, next) { 2799 if (obj->marker || obj->doomed) 2800 continue; 2801 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2802 break; 2803 } 2804 if (obj != NULL) { 2805 if (name != NULL) 2806 object_add_name(obj, name); 2807 free(path); 2808 close(fd); 2809 return (obj); 2810 } 2811 if (flags & RTLD_LO_NOLOAD) { 2812 free(path); 2813 close(fd); 2814 return (NULL); 2815 } 2816 2817 /* First use of this object, so we must map it in */ 2818 obj = do_load_object(fd, name, path, &sb, flags); 2819 if (obj == NULL) 2820 free(path); 2821 close(fd); 2822 2823 return (obj); 2824 } 2825 2826 static Obj_Entry * 2827 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2828 int flags) 2829 { 2830 Obj_Entry *obj; 2831 struct statfs fs; 2832 2833 /* 2834 * First, make sure that environment variables haven't been 2835 * used to circumvent the noexec flag on a filesystem. 2836 * We ignore fstatfs(2) failures, since fd might reference 2837 * not a file, e.g. shmfd. 2838 */ 2839 if (dangerous_ld_env && fstatfs(fd, &fs) == 0 && 2840 (fs.f_flags & MNT_NOEXEC) != 0) { 2841 _rtld_error("Cannot execute objects on %s", fs.f_mntonname); 2842 return (NULL); 2843 } 2844 2845 dbg("loading \"%s\"", printable_path(path)); 2846 obj = map_object(fd, printable_path(path), sbp); 2847 if (obj == NULL) 2848 return (NULL); 2849 2850 /* 2851 * If DT_SONAME is present in the object, digest_dynamic2 already 2852 * added it to the object names. 2853 */ 2854 if (name != NULL) 2855 object_add_name(obj, name); 2856 obj->path = path; 2857 if (!digest_dynamic(obj, 0)) 2858 goto errp; 2859 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2860 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2861 if (obj->z_pie && (flags & RTLD_LO_TRACE) == 0) { 2862 dbg("refusing to load PIE executable \"%s\"", obj->path); 2863 _rtld_error("Cannot load PIE binary %s as DSO", obj->path); 2864 goto errp; 2865 } 2866 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2867 RTLD_LO_DLOPEN) { 2868 dbg("refusing to load non-loadable \"%s\"", obj->path); 2869 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2870 goto errp; 2871 } 2872 2873 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2874 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2875 obj_count++; 2876 obj_loads++; 2877 linkmap_add(obj); /* for GDB & dlinfo() */ 2878 max_stack_flags |= obj->stack_flags; 2879 2880 dbg(" %p .. %p: %s", obj->mapbase, 2881 obj->mapbase + obj->mapsize - 1, obj->path); 2882 if (obj->textrel) 2883 dbg(" WARNING: %s has impure text", obj->path); 2884 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2885 obj->path); 2886 2887 return (obj); 2888 2889 errp: 2890 munmap(obj->mapbase, obj->mapsize); 2891 obj_free(obj); 2892 return (NULL); 2893 } 2894 2895 static int 2896 load_kpreload(const void *addr) 2897 { 2898 Obj_Entry *obj; 2899 const Elf_Ehdr *ehdr; 2900 const Elf_Phdr *phdr, *phlimit, *phdyn, *seg0, *segn; 2901 static const char kname[] = "[vdso]"; 2902 2903 ehdr = addr; 2904 if (!check_elf_headers(ehdr, "kpreload")) 2905 return (-1); 2906 obj = obj_new(); 2907 phdr = (const Elf_Phdr *)((const char *)addr + ehdr->e_phoff); 2908 obj->phdr = phdr; 2909 obj->phsize = ehdr->e_phnum * sizeof(*phdr); 2910 phlimit = phdr + ehdr->e_phnum; 2911 seg0 = segn = NULL; 2912 2913 for (; phdr < phlimit; phdr++) { 2914 switch (phdr->p_type) { 2915 case PT_DYNAMIC: 2916 phdyn = phdr; 2917 break; 2918 case PT_GNU_STACK: 2919 /* Absense of PT_GNU_STACK implies stack_flags == 0. */ 2920 obj->stack_flags = phdr->p_flags; 2921 break; 2922 case PT_LOAD: 2923 if (seg0 == NULL || seg0->p_vaddr > phdr->p_vaddr) 2924 seg0 = phdr; 2925 if (segn == NULL || segn->p_vaddr + segn->p_memsz < 2926 phdr->p_vaddr + phdr->p_memsz) 2927 segn = phdr; 2928 break; 2929 } 2930 } 2931 2932 obj->mapbase = __DECONST(caddr_t, addr); 2933 obj->mapsize = segn->p_vaddr + segn->p_memsz - (Elf_Addr)addr; 2934 obj->vaddrbase = 0; 2935 obj->relocbase = obj->mapbase; 2936 2937 object_add_name(obj, kname); 2938 obj->path = xstrdup(kname); 2939 obj->dynamic = (const Elf_Dyn *)(obj->relocbase + phdyn->p_vaddr); 2940 2941 if (!digest_dynamic(obj, 0)) { 2942 obj_free(obj); 2943 return (-1); 2944 } 2945 2946 /* 2947 * We assume that kernel-preloaded object does not need 2948 * relocation. It is currently written into read-only page, 2949 * handling relocations would mean we need to allocate at 2950 * least one additional page per AS. 2951 */ 2952 dbg("%s mapbase %p phdrs %p PT_LOAD phdr %p vaddr %p dynamic %p", 2953 obj->path, obj->mapbase, obj->phdr, seg0, 2954 obj->relocbase + seg0->p_vaddr, obj->dynamic); 2955 2956 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2957 obj_count++; 2958 obj_loads++; 2959 linkmap_add(obj); /* for GDB & dlinfo() */ 2960 max_stack_flags |= obj->stack_flags; 2961 2962 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, 0, 0, obj->path); 2963 return (0); 2964 } 2965 2966 Obj_Entry * 2967 obj_from_addr(const void *addr) 2968 { 2969 Obj_Entry *obj; 2970 2971 TAILQ_FOREACH(obj, &obj_list, next) { 2972 if (obj->marker) 2973 continue; 2974 if (addr < (void *) obj->mapbase) 2975 continue; 2976 if (addr < (void *)(obj->mapbase + obj->mapsize)) 2977 return obj; 2978 } 2979 return (NULL); 2980 } 2981 2982 static void 2983 preinit_main(void) 2984 { 2985 Elf_Addr *preinit_addr; 2986 int index; 2987 2988 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2989 if (preinit_addr == NULL) 2990 return; 2991 2992 for (index = 0; index < obj_main->preinit_array_num; index++) { 2993 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2994 dbg("calling preinit function for %s at %p", obj_main->path, 2995 (void *)preinit_addr[index]); 2996 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2997 0, 0, obj_main->path); 2998 call_init_pointer(obj_main, preinit_addr[index]); 2999 } 3000 } 3001 } 3002 3003 /* 3004 * Call the finalization functions for each of the objects in "list" 3005 * belonging to the DAG of "root" and referenced once. If NULL "root" 3006 * is specified, every finalization function will be called regardless 3007 * of the reference count and the list elements won't be freed. All of 3008 * the objects are expected to have non-NULL fini functions. 3009 */ 3010 static void 3011 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 3012 { 3013 Objlist_Entry *elm; 3014 struct dlerror_save *saved_msg; 3015 Elf_Addr *fini_addr; 3016 int index; 3017 3018 assert(root == NULL || root->refcount == 1); 3019 3020 if (root != NULL) 3021 root->doomed = true; 3022 3023 /* 3024 * Preserve the current error message since a fini function might 3025 * call into the dynamic linker and overwrite it. 3026 */ 3027 saved_msg = errmsg_save(); 3028 do { 3029 STAILQ_FOREACH(elm, list, link) { 3030 if (root != NULL && (elm->obj->refcount != 1 || 3031 objlist_find(&root->dagmembers, elm->obj) == NULL)) 3032 continue; 3033 /* Remove object from fini list to prevent recursive invocation. */ 3034 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 3035 /* Ensure that new references cannot be acquired. */ 3036 elm->obj->doomed = true; 3037 3038 hold_object(elm->obj); 3039 lock_release(rtld_bind_lock, lockstate); 3040 /* 3041 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 3042 * When this happens, DT_FINI_ARRAY is processed first. 3043 */ 3044 fini_addr = (Elf_Addr *)elm->obj->fini_array; 3045 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 3046 for (index = elm->obj->fini_array_num - 1; index >= 0; 3047 index--) { 3048 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 3049 dbg("calling fini function for %s at %p", 3050 elm->obj->path, (void *)fini_addr[index]); 3051 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 3052 (void *)fini_addr[index], 0, 0, elm->obj->path); 3053 call_initfini_pointer(elm->obj, fini_addr[index]); 3054 } 3055 } 3056 } 3057 if (elm->obj->fini != (Elf_Addr)NULL) { 3058 dbg("calling fini function for %s at %p", elm->obj->path, 3059 (void *)elm->obj->fini); 3060 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 3061 0, 0, elm->obj->path); 3062 call_initfini_pointer(elm->obj, elm->obj->fini); 3063 } 3064 wlock_acquire(rtld_bind_lock, lockstate); 3065 unhold_object(elm->obj); 3066 /* No need to free anything if process is going down. */ 3067 if (root != NULL) 3068 free(elm); 3069 /* 3070 * We must restart the list traversal after every fini call 3071 * because a dlclose() call from the fini function or from 3072 * another thread might have modified the reference counts. 3073 */ 3074 break; 3075 } 3076 } while (elm != NULL); 3077 errmsg_restore(saved_msg); 3078 } 3079 3080 /* 3081 * Call the initialization functions for each of the objects in 3082 * "list". All of the objects are expected to have non-NULL init 3083 * functions. 3084 */ 3085 static void 3086 objlist_call_init(Objlist *list, RtldLockState *lockstate) 3087 { 3088 Objlist_Entry *elm; 3089 Obj_Entry *obj; 3090 struct dlerror_save *saved_msg; 3091 Elf_Addr *init_addr; 3092 void (*reg)(void (*)(void)); 3093 int index; 3094 3095 /* 3096 * Clean init_scanned flag so that objects can be rechecked and 3097 * possibly initialized earlier if any of vectors called below 3098 * cause the change by using dlopen. 3099 */ 3100 TAILQ_FOREACH(obj, &obj_list, next) { 3101 if (obj->marker) 3102 continue; 3103 obj->init_scanned = false; 3104 } 3105 3106 /* 3107 * Preserve the current error message since an init function might 3108 * call into the dynamic linker and overwrite it. 3109 */ 3110 saved_msg = errmsg_save(); 3111 STAILQ_FOREACH(elm, list, link) { 3112 if (elm->obj->init_done) /* Initialized early. */ 3113 continue; 3114 /* 3115 * Race: other thread might try to use this object before current 3116 * one completes the initialization. Not much can be done here 3117 * without better locking. 3118 */ 3119 elm->obj->init_done = true; 3120 hold_object(elm->obj); 3121 reg = NULL; 3122 if (elm->obj == obj_main && obj_main->crt_no_init) { 3123 reg = (void (*)(void (*)(void)))get_program_var_addr( 3124 "__libc_atexit", lockstate); 3125 } 3126 lock_release(rtld_bind_lock, lockstate); 3127 if (reg != NULL) { 3128 reg(rtld_exit); 3129 rtld_exit_ptr = rtld_nop_exit; 3130 } 3131 3132 /* 3133 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 3134 * When this happens, DT_INIT is processed first. 3135 */ 3136 if (elm->obj->init != (Elf_Addr)NULL) { 3137 dbg("calling init function for %s at %p", elm->obj->path, 3138 (void *)elm->obj->init); 3139 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 3140 0, 0, elm->obj->path); 3141 call_init_pointer(elm->obj, elm->obj->init); 3142 } 3143 init_addr = (Elf_Addr *)elm->obj->init_array; 3144 if (init_addr != NULL) { 3145 for (index = 0; index < elm->obj->init_array_num; index++) { 3146 if (init_addr[index] != 0 && init_addr[index] != 1) { 3147 dbg("calling init function for %s at %p", elm->obj->path, 3148 (void *)init_addr[index]); 3149 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 3150 (void *)init_addr[index], 0, 0, elm->obj->path); 3151 call_init_pointer(elm->obj, init_addr[index]); 3152 } 3153 } 3154 } 3155 wlock_acquire(rtld_bind_lock, lockstate); 3156 unhold_object(elm->obj); 3157 } 3158 errmsg_restore(saved_msg); 3159 } 3160 3161 static void 3162 objlist_clear(Objlist *list) 3163 { 3164 Objlist_Entry *elm; 3165 3166 while (!STAILQ_EMPTY(list)) { 3167 elm = STAILQ_FIRST(list); 3168 STAILQ_REMOVE_HEAD(list, link); 3169 free(elm); 3170 } 3171 } 3172 3173 static Objlist_Entry * 3174 objlist_find(Objlist *list, const Obj_Entry *obj) 3175 { 3176 Objlist_Entry *elm; 3177 3178 STAILQ_FOREACH(elm, list, link) 3179 if (elm->obj == obj) 3180 return elm; 3181 return (NULL); 3182 } 3183 3184 static void 3185 objlist_init(Objlist *list) 3186 { 3187 STAILQ_INIT(list); 3188 } 3189 3190 static void 3191 objlist_push_head(Objlist *list, Obj_Entry *obj) 3192 { 3193 Objlist_Entry *elm; 3194 3195 elm = NEW(Objlist_Entry); 3196 elm->obj = obj; 3197 STAILQ_INSERT_HEAD(list, elm, link); 3198 } 3199 3200 static void 3201 objlist_push_tail(Objlist *list, Obj_Entry *obj) 3202 { 3203 Objlist_Entry *elm; 3204 3205 elm = NEW(Objlist_Entry); 3206 elm->obj = obj; 3207 STAILQ_INSERT_TAIL(list, elm, link); 3208 } 3209 3210 static void 3211 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 3212 { 3213 Objlist_Entry *elm, *listelm; 3214 3215 STAILQ_FOREACH(listelm, list, link) { 3216 if (listelm->obj == listobj) 3217 break; 3218 } 3219 elm = NEW(Objlist_Entry); 3220 elm->obj = obj; 3221 if (listelm != NULL) 3222 STAILQ_INSERT_AFTER(list, listelm, elm, link); 3223 else 3224 STAILQ_INSERT_TAIL(list, elm, link); 3225 } 3226 3227 static void 3228 objlist_remove(Objlist *list, Obj_Entry *obj) 3229 { 3230 Objlist_Entry *elm; 3231 3232 if ((elm = objlist_find(list, obj)) != NULL) { 3233 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 3234 free(elm); 3235 } 3236 } 3237 3238 /* 3239 * Relocate dag rooted in the specified object. 3240 * Returns 0 on success, or -1 on failure. 3241 */ 3242 3243 static int 3244 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 3245 int flags, RtldLockState *lockstate) 3246 { 3247 Objlist_Entry *elm; 3248 int error; 3249 3250 error = 0; 3251 STAILQ_FOREACH(elm, &root->dagmembers, link) { 3252 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 3253 lockstate); 3254 if (error == -1) 3255 break; 3256 } 3257 return (error); 3258 } 3259 3260 /* 3261 * Prepare for, or clean after, relocating an object marked with 3262 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 3263 * segments are remapped read-write. After relocations are done, the 3264 * segment's permissions are returned back to the modes specified in 3265 * the phdrs. If any relocation happened, or always for wired 3266 * program, COW is triggered. 3267 */ 3268 static int 3269 reloc_textrel_prot(Obj_Entry *obj, bool before) 3270 { 3271 const Elf_Phdr *ph; 3272 void *base; 3273 size_t l, sz; 3274 int prot; 3275 3276 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 3277 l--, ph++) { 3278 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 3279 continue; 3280 base = obj->relocbase + rtld_trunc_page(ph->p_vaddr); 3281 sz = rtld_round_page(ph->p_vaddr + ph->p_filesz) - 3282 rtld_trunc_page(ph->p_vaddr); 3283 prot = before ? (PROT_READ | PROT_WRITE) : 3284 convert_prot(ph->p_flags); 3285 if (mprotect(base, sz, prot) == -1) { 3286 _rtld_error("%s: Cannot write-%sable text segment: %s", 3287 obj->path, before ? "en" : "dis", 3288 rtld_strerror(errno)); 3289 return (-1); 3290 } 3291 } 3292 return (0); 3293 } 3294 3295 /* Process RELR relative relocations. */ 3296 static void 3297 reloc_relr(Obj_Entry *obj) 3298 { 3299 const Elf_Relr *relr, *relrlim; 3300 Elf_Addr *where; 3301 3302 relrlim = (const Elf_Relr *)((const char *)obj->relr + obj->relrsize); 3303 for (relr = obj->relr; relr < relrlim; relr++) { 3304 Elf_Relr entry = *relr; 3305 3306 if ((entry & 1) == 0) { 3307 where = (Elf_Addr *)(obj->relocbase + entry); 3308 *where++ += (Elf_Addr)obj->relocbase; 3309 } else { 3310 for (long i = 0; (entry >>= 1) != 0; i++) 3311 if ((entry & 1) != 0) 3312 where[i] += (Elf_Addr)obj->relocbase; 3313 where += CHAR_BIT * sizeof(Elf_Relr) - 1; 3314 } 3315 } 3316 } 3317 3318 /* 3319 * Relocate single object. 3320 * Returns 0 on success, or -1 on failure. 3321 */ 3322 static int 3323 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 3324 int flags, RtldLockState *lockstate) 3325 { 3326 3327 if (obj->relocated) 3328 return (0); 3329 obj->relocated = true; 3330 if (obj != rtldobj) 3331 dbg("relocating \"%s\"", obj->path); 3332 3333 if (obj->symtab == NULL || obj->strtab == NULL || 3334 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) 3335 dbg("object %s has no run-time symbol table", obj->path); 3336 3337 /* There are relocations to the write-protected text segment. */ 3338 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 3339 return (-1); 3340 3341 /* Process the non-PLT non-IFUNC relocations. */ 3342 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 3343 return (-1); 3344 reloc_relr(obj); 3345 3346 /* Re-protected the text segment. */ 3347 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 3348 return (-1); 3349 3350 /* Set the special PLT or GOT entries. */ 3351 init_pltgot(obj); 3352 3353 /* Process the PLT relocations. */ 3354 if (reloc_plt(obj, flags, lockstate) == -1) 3355 return (-1); 3356 /* Relocate the jump slots if we are doing immediate binding. */ 3357 if ((obj->bind_now || bind_now) && reloc_jmpslots(obj, flags, 3358 lockstate) == -1) 3359 return (-1); 3360 3361 if (!obj->mainprog && obj_enforce_relro(obj) == -1) 3362 return (-1); 3363 3364 /* 3365 * Set up the magic number and version in the Obj_Entry. These 3366 * were checked in the crt1.o from the original ElfKit, so we 3367 * set them for backward compatibility. 3368 */ 3369 obj->magic = RTLD_MAGIC; 3370 obj->version = RTLD_VERSION; 3371 3372 return (0); 3373 } 3374 3375 /* 3376 * Relocate newly-loaded shared objects. The argument is a pointer to 3377 * the Obj_Entry for the first such object. All objects from the first 3378 * to the end of the list of objects are relocated. Returns 0 on success, 3379 * or -1 on failure. 3380 */ 3381 static int 3382 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 3383 int flags, RtldLockState *lockstate) 3384 { 3385 Obj_Entry *obj; 3386 int error; 3387 3388 for (error = 0, obj = first; obj != NULL; 3389 obj = TAILQ_NEXT(obj, next)) { 3390 if (obj->marker) 3391 continue; 3392 error = relocate_object(obj, bind_now, rtldobj, flags, 3393 lockstate); 3394 if (error == -1) 3395 break; 3396 } 3397 return (error); 3398 } 3399 3400 /* 3401 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 3402 * referencing STT_GNU_IFUNC symbols is postponed till the other 3403 * relocations are done. The indirect functions specified as 3404 * ifunc are allowed to call other symbols, so we need to have 3405 * objects relocated before asking for resolution from indirects. 3406 * 3407 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 3408 * instead of the usual lazy handling of PLT slots. It is 3409 * consistent with how GNU does it. 3410 */ 3411 static int 3412 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 3413 RtldLockState *lockstate) 3414 { 3415 3416 if (obj->ifuncs_resolved) 3417 return (0); 3418 obj->ifuncs_resolved = true; 3419 if (!obj->irelative && !obj->irelative_nonplt && 3420 !((obj->bind_now || bind_now) && obj->gnu_ifunc) && 3421 !obj->non_plt_gnu_ifunc) 3422 return (0); 3423 if (obj_disable_relro(obj) == -1 || 3424 (obj->irelative && reloc_iresolve(obj, lockstate) == -1) || 3425 (obj->irelative_nonplt && reloc_iresolve_nonplt(obj, 3426 lockstate) == -1) || 3427 ((obj->bind_now || bind_now) && obj->gnu_ifunc && 3428 reloc_gnu_ifunc(obj, flags, lockstate) == -1) || 3429 (obj->non_plt_gnu_ifunc && reloc_non_plt(obj, &obj_rtld, 3430 flags | SYMLOOK_IFUNC, lockstate) == -1) || 3431 obj_enforce_relro(obj) == -1) 3432 return (-1); 3433 return (0); 3434 } 3435 3436 static int 3437 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 3438 RtldLockState *lockstate) 3439 { 3440 Objlist_Entry *elm; 3441 Obj_Entry *obj; 3442 3443 STAILQ_FOREACH(elm, list, link) { 3444 obj = elm->obj; 3445 if (obj->marker) 3446 continue; 3447 if (resolve_object_ifunc(obj, bind_now, flags, 3448 lockstate) == -1) 3449 return (-1); 3450 } 3451 return (0); 3452 } 3453 3454 /* 3455 * Cleanup procedure. It will be called (by the atexit mechanism) just 3456 * before the process exits. 3457 */ 3458 static void 3459 rtld_exit(void) 3460 { 3461 RtldLockState lockstate; 3462 3463 wlock_acquire(rtld_bind_lock, &lockstate); 3464 dbg("rtld_exit()"); 3465 objlist_call_fini(&list_fini, NULL, &lockstate); 3466 /* No need to remove the items from the list, since we are exiting. */ 3467 if (!libmap_disable) 3468 lm_fini(); 3469 lock_release(rtld_bind_lock, &lockstate); 3470 } 3471 3472 static void 3473 rtld_nop_exit(void) 3474 { 3475 } 3476 3477 /* 3478 * Iterate over a search path, translate each element, and invoke the 3479 * callback on the result. 3480 */ 3481 static void * 3482 path_enumerate(const char *path, path_enum_proc callback, 3483 const char *refobj_path, void *arg) 3484 { 3485 const char *trans; 3486 if (path == NULL) 3487 return (NULL); 3488 3489 path += strspn(path, ":;"); 3490 while (*path != '\0') { 3491 size_t len; 3492 char *res; 3493 3494 len = strcspn(path, ":;"); 3495 trans = lm_findn(refobj_path, path, len); 3496 if (trans) 3497 res = callback(trans, strlen(trans), arg); 3498 else 3499 res = callback(path, len, arg); 3500 3501 if (res != NULL) 3502 return (res); 3503 3504 path += len; 3505 path += strspn(path, ":;"); 3506 } 3507 3508 return (NULL); 3509 } 3510 3511 struct try_library_args { 3512 const char *name; 3513 size_t namelen; 3514 char *buffer; 3515 size_t buflen; 3516 int fd; 3517 }; 3518 3519 static void * 3520 try_library_path(const char *dir, size_t dirlen, void *param) 3521 { 3522 struct try_library_args *arg; 3523 int fd; 3524 3525 arg = param; 3526 if (*dir == '/' || trust) { 3527 char *pathname; 3528 3529 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 3530 return (NULL); 3531 3532 pathname = arg->buffer; 3533 strncpy(pathname, dir, dirlen); 3534 pathname[dirlen] = '/'; 3535 strcpy(pathname + dirlen + 1, arg->name); 3536 3537 dbg(" Trying \"%s\"", pathname); 3538 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY); 3539 if (fd >= 0) { 3540 dbg(" Opened \"%s\", fd %d", pathname, fd); 3541 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 3542 strcpy(pathname, arg->buffer); 3543 arg->fd = fd; 3544 return (pathname); 3545 } else { 3546 dbg(" Failed to open \"%s\": %s", 3547 pathname, rtld_strerror(errno)); 3548 } 3549 } 3550 return (NULL); 3551 } 3552 3553 static char * 3554 search_library_path(const char *name, const char *path, 3555 const char *refobj_path, int *fdp) 3556 { 3557 char *p; 3558 struct try_library_args arg; 3559 3560 if (path == NULL) 3561 return (NULL); 3562 3563 arg.name = name; 3564 arg.namelen = strlen(name); 3565 arg.buffer = xmalloc(PATH_MAX); 3566 arg.buflen = PATH_MAX; 3567 arg.fd = -1; 3568 3569 p = path_enumerate(path, try_library_path, refobj_path, &arg); 3570 *fdp = arg.fd; 3571 3572 free(arg.buffer); 3573 3574 return (p); 3575 } 3576 3577 3578 /* 3579 * Finds the library with the given name using the directory descriptors 3580 * listed in the LD_LIBRARY_PATH_FDS environment variable. 3581 * 3582 * Returns a freshly-opened close-on-exec file descriptor for the library, 3583 * or -1 if the library cannot be found. 3584 */ 3585 static char * 3586 search_library_pathfds(const char *name, const char *path, int *fdp) 3587 { 3588 char *envcopy, *fdstr, *found, *last_token; 3589 size_t len; 3590 int dirfd, fd; 3591 3592 dbg("%s('%s', '%s', fdp)", __func__, name, path); 3593 3594 /* Don't load from user-specified libdirs into setuid binaries. */ 3595 if (!trust) 3596 return (NULL); 3597 3598 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 3599 if (path == NULL) 3600 return (NULL); 3601 3602 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 3603 if (name[0] == '/') { 3604 dbg("Absolute path (%s) passed to %s", name, __func__); 3605 return (NULL); 3606 } 3607 3608 /* 3609 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 3610 * copy of the path, as strtok_r rewrites separator tokens 3611 * with '\0'. 3612 */ 3613 found = NULL; 3614 envcopy = xstrdup(path); 3615 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 3616 fdstr = strtok_r(NULL, ":", &last_token)) { 3617 dirfd = parse_integer(fdstr); 3618 if (dirfd < 0) { 3619 _rtld_error("failed to parse directory FD: '%s'", 3620 fdstr); 3621 break; 3622 } 3623 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 3624 if (fd >= 0) { 3625 *fdp = fd; 3626 len = strlen(fdstr) + strlen(name) + 3; 3627 found = xmalloc(len); 3628 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 3629 _rtld_error("error generating '%d/%s'", 3630 dirfd, name); 3631 rtld_die(); 3632 } 3633 dbg("open('%s') => %d", found, fd); 3634 break; 3635 } 3636 } 3637 free(envcopy); 3638 3639 return (found); 3640 } 3641 3642 3643 int 3644 dlclose(void *handle) 3645 { 3646 RtldLockState lockstate; 3647 int error; 3648 3649 wlock_acquire(rtld_bind_lock, &lockstate); 3650 error = dlclose_locked(handle, &lockstate); 3651 lock_release(rtld_bind_lock, &lockstate); 3652 return (error); 3653 } 3654 3655 static int 3656 dlclose_locked(void *handle, RtldLockState *lockstate) 3657 { 3658 Obj_Entry *root; 3659 3660 root = dlcheck(handle); 3661 if (root == NULL) 3662 return (-1); 3663 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 3664 root->path); 3665 3666 /* Unreference the object and its dependencies. */ 3667 root->dl_refcount--; 3668 3669 if (root->refcount == 1) { 3670 /* 3671 * The object will be no longer referenced, so we must unload it. 3672 * First, call the fini functions. 3673 */ 3674 objlist_call_fini(&list_fini, root, lockstate); 3675 3676 unref_dag(root); 3677 3678 /* Finish cleaning up the newly-unreferenced objects. */ 3679 GDB_STATE(RT_DELETE,&root->linkmap); 3680 unload_object(root, lockstate); 3681 GDB_STATE(RT_CONSISTENT,NULL); 3682 } else 3683 unref_dag(root); 3684 3685 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 3686 return (0); 3687 } 3688 3689 char * 3690 dlerror(void) 3691 { 3692 if (*(lockinfo.dlerror_seen()) != 0) 3693 return (NULL); 3694 *lockinfo.dlerror_seen() = 1; 3695 return (lockinfo.dlerror_loc()); 3696 } 3697 3698 /* 3699 * This function is deprecated and has no effect. 3700 */ 3701 void 3702 dllockinit(void *context, 3703 void *(*_lock_create)(void *context) __unused, 3704 void (*_rlock_acquire)(void *lock) __unused, 3705 void (*_wlock_acquire)(void *lock) __unused, 3706 void (*_lock_release)(void *lock) __unused, 3707 void (*_lock_destroy)(void *lock) __unused, 3708 void (*context_destroy)(void *context)) 3709 { 3710 static void *cur_context; 3711 static void (*cur_context_destroy)(void *); 3712 3713 /* Just destroy the context from the previous call, if necessary. */ 3714 if (cur_context_destroy != NULL) 3715 cur_context_destroy(cur_context); 3716 cur_context = context; 3717 cur_context_destroy = context_destroy; 3718 } 3719 3720 void * 3721 dlopen(const char *name, int mode) 3722 { 3723 3724 return (rtld_dlopen(name, -1, mode)); 3725 } 3726 3727 void * 3728 fdlopen(int fd, int mode) 3729 { 3730 3731 return (rtld_dlopen(NULL, fd, mode)); 3732 } 3733 3734 static void * 3735 rtld_dlopen(const char *name, int fd, int mode) 3736 { 3737 RtldLockState lockstate; 3738 int lo_flags; 3739 3740 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3741 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3742 if (ld_tracing != NULL) { 3743 rlock_acquire(rtld_bind_lock, &lockstate); 3744 if (sigsetjmp(lockstate.env, 0) != 0) 3745 lock_upgrade(rtld_bind_lock, &lockstate); 3746 environ = __DECONST(char **, *get_program_var_addr("environ", &lockstate)); 3747 lock_release(rtld_bind_lock, &lockstate); 3748 } 3749 lo_flags = RTLD_LO_DLOPEN; 3750 if (mode & RTLD_NODELETE) 3751 lo_flags |= RTLD_LO_NODELETE; 3752 if (mode & RTLD_NOLOAD) 3753 lo_flags |= RTLD_LO_NOLOAD; 3754 if (mode & RTLD_DEEPBIND) 3755 lo_flags |= RTLD_LO_DEEPBIND; 3756 if (ld_tracing != NULL) 3757 lo_flags |= RTLD_LO_TRACE | RTLD_LO_IGNSTLS; 3758 3759 return (dlopen_object(name, fd, obj_main, lo_flags, 3760 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3761 } 3762 3763 static void 3764 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate) 3765 { 3766 3767 obj->dl_refcount--; 3768 unref_dag(obj); 3769 if (obj->refcount == 0) 3770 unload_object(obj, lockstate); 3771 } 3772 3773 static Obj_Entry * 3774 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3775 int mode, RtldLockState *lockstate) 3776 { 3777 Obj_Entry *obj; 3778 Objlist initlist; 3779 RtldLockState mlockstate; 3780 int result; 3781 3782 dbg("dlopen_object name \"%s\" fd %d refobj \"%s\" lo_flags %#x mode %#x", 3783 name != NULL ? name : "<null>", fd, refobj == NULL ? "<null>" : 3784 refobj->path, lo_flags, mode); 3785 objlist_init(&initlist); 3786 3787 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3788 wlock_acquire(rtld_bind_lock, &mlockstate); 3789 lockstate = &mlockstate; 3790 } 3791 GDB_STATE(RT_ADD,NULL); 3792 3793 obj = NULL; 3794 if (name == NULL && fd == -1) { 3795 obj = obj_main; 3796 obj->refcount++; 3797 } else { 3798 obj = load_object(name, fd, refobj, lo_flags); 3799 } 3800 3801 if (obj) { 3802 obj->dl_refcount++; 3803 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3804 objlist_push_tail(&list_global, obj); 3805 3806 if (!obj->init_done) { 3807 /* We loaded something new and have to init something. */ 3808 if ((lo_flags & RTLD_LO_DEEPBIND) != 0) 3809 obj->deepbind = true; 3810 result = 0; 3811 if ((lo_flags & (RTLD_LO_EARLY | RTLD_LO_IGNSTLS)) == 0 && 3812 obj->static_tls && !allocate_tls_offset(obj)) { 3813 _rtld_error("%s: No space available " 3814 "for static Thread Local Storage", obj->path); 3815 result = -1; 3816 } 3817 if (result != -1) 3818 result = load_needed_objects(obj, lo_flags & (RTLD_LO_DLOPEN | 3819 RTLD_LO_EARLY | RTLD_LO_IGNSTLS | RTLD_LO_TRACE)); 3820 init_dag(obj); 3821 ref_dag(obj); 3822 if (result != -1) 3823 result = rtld_verify_versions(&obj->dagmembers); 3824 if (result != -1 && ld_tracing) 3825 goto trace; 3826 if (result == -1 || relocate_object_dag(obj, 3827 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3828 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3829 lockstate) == -1) { 3830 dlopen_cleanup(obj, lockstate); 3831 obj = NULL; 3832 } else if (lo_flags & RTLD_LO_EARLY) { 3833 /* 3834 * Do not call the init functions for early loaded 3835 * filtees. The image is still not initialized enough 3836 * for them to work. 3837 * 3838 * Our object is found by the global object list and 3839 * will be ordered among all init calls done right 3840 * before transferring control to main. 3841 */ 3842 } else { 3843 /* Make list of init functions to call. */ 3844 initlist_add_objects(obj, obj, &initlist); 3845 } 3846 /* 3847 * Process all no_delete or global objects here, given 3848 * them own DAGs to prevent their dependencies from being 3849 * unloaded. This has to be done after we have loaded all 3850 * of the dependencies, so that we do not miss any. 3851 */ 3852 if (obj != NULL) 3853 process_z(obj); 3854 } else { 3855 /* 3856 * Bump the reference counts for objects on this DAG. If 3857 * this is the first dlopen() call for the object that was 3858 * already loaded as a dependency, initialize the dag 3859 * starting at it. 3860 */ 3861 init_dag(obj); 3862 ref_dag(obj); 3863 3864 if ((lo_flags & RTLD_LO_TRACE) != 0) 3865 goto trace; 3866 } 3867 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3868 obj->z_nodelete) && !obj->ref_nodel) { 3869 dbg("obj %s nodelete", obj->path); 3870 ref_dag(obj); 3871 obj->z_nodelete = obj->ref_nodel = true; 3872 } 3873 } 3874 3875 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3876 name); 3877 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3878 3879 if ((lo_flags & RTLD_LO_EARLY) == 0) { 3880 map_stacks_exec(lockstate); 3881 if (obj != NULL) 3882 distribute_static_tls(&initlist, lockstate); 3883 } 3884 3885 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3886 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3887 lockstate) == -1) { 3888 objlist_clear(&initlist); 3889 dlopen_cleanup(obj, lockstate); 3890 if (lockstate == &mlockstate) 3891 lock_release(rtld_bind_lock, lockstate); 3892 return (NULL); 3893 } 3894 3895 if (!(lo_flags & RTLD_LO_EARLY)) { 3896 /* Call the init functions. */ 3897 objlist_call_init(&initlist, lockstate); 3898 } 3899 objlist_clear(&initlist); 3900 if (lockstate == &mlockstate) 3901 lock_release(rtld_bind_lock, lockstate); 3902 return (obj); 3903 trace: 3904 trace_loaded_objects(obj, false); 3905 if (lockstate == &mlockstate) 3906 lock_release(rtld_bind_lock, lockstate); 3907 exit(0); 3908 } 3909 3910 static void * 3911 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3912 int flags) 3913 { 3914 DoneList donelist; 3915 const Obj_Entry *obj, *defobj; 3916 const Elf_Sym *def; 3917 SymLook req; 3918 RtldLockState lockstate; 3919 tls_index ti; 3920 void *sym; 3921 int res; 3922 3923 def = NULL; 3924 defobj = NULL; 3925 symlook_init(&req, name); 3926 req.ventry = ve; 3927 req.flags = flags | SYMLOOK_IN_PLT; 3928 req.lockstate = &lockstate; 3929 3930 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3931 rlock_acquire(rtld_bind_lock, &lockstate); 3932 if (sigsetjmp(lockstate.env, 0) != 0) 3933 lock_upgrade(rtld_bind_lock, &lockstate); 3934 if (handle == NULL || handle == RTLD_NEXT || 3935 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3936 3937 if ((obj = obj_from_addr(retaddr)) == NULL) { 3938 _rtld_error("Cannot determine caller's shared object"); 3939 lock_release(rtld_bind_lock, &lockstate); 3940 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3941 return (NULL); 3942 } 3943 if (handle == NULL) { /* Just the caller's shared object. */ 3944 res = symlook_obj(&req, obj); 3945 if (res == 0) { 3946 def = req.sym_out; 3947 defobj = req.defobj_out; 3948 } 3949 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3950 handle == RTLD_SELF) { /* ... caller included */ 3951 if (handle == RTLD_NEXT) 3952 obj = globallist_next(obj); 3953 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3954 if (obj->marker) 3955 continue; 3956 res = symlook_obj(&req, obj); 3957 if (res == 0) { 3958 if (def == NULL || (ld_dynamic_weak && 3959 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK)) { 3960 def = req.sym_out; 3961 defobj = req.defobj_out; 3962 if (!ld_dynamic_weak || 3963 ELF_ST_BIND(def->st_info) != STB_WEAK) 3964 break; 3965 } 3966 } 3967 } 3968 /* 3969 * Search the dynamic linker itself, and possibly resolve the 3970 * symbol from there. This is how the application links to 3971 * dynamic linker services such as dlopen. 3972 * Note that we ignore ld_dynamic_weak == false case, 3973 * always overriding weak symbols by rtld definitions. 3974 */ 3975 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3976 res = symlook_obj(&req, &obj_rtld); 3977 if (res == 0) { 3978 def = req.sym_out; 3979 defobj = req.defobj_out; 3980 } 3981 } 3982 } else { 3983 assert(handle == RTLD_DEFAULT); 3984 res = symlook_default(&req, obj); 3985 if (res == 0) { 3986 defobj = req.defobj_out; 3987 def = req.sym_out; 3988 } 3989 } 3990 } else { 3991 if ((obj = dlcheck(handle)) == NULL) { 3992 lock_release(rtld_bind_lock, &lockstate); 3993 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3994 return (NULL); 3995 } 3996 3997 donelist_init(&donelist); 3998 if (obj->mainprog) { 3999 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 4000 res = symlook_global(&req, &donelist); 4001 if (res == 0) { 4002 def = req.sym_out; 4003 defobj = req.defobj_out; 4004 } 4005 /* 4006 * Search the dynamic linker itself, and possibly resolve the 4007 * symbol from there. This is how the application links to 4008 * dynamic linker services such as dlopen. 4009 */ 4010 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 4011 res = symlook_obj(&req, &obj_rtld); 4012 if (res == 0) { 4013 def = req.sym_out; 4014 defobj = req.defobj_out; 4015 } 4016 } 4017 } 4018 else { 4019 /* Search the whole DAG rooted at the given object. */ 4020 res = symlook_list(&req, &obj->dagmembers, &donelist); 4021 if (res == 0) { 4022 def = req.sym_out; 4023 defobj = req.defobj_out; 4024 } 4025 } 4026 } 4027 4028 if (def != NULL) { 4029 lock_release(rtld_bind_lock, &lockstate); 4030 4031 /* 4032 * The value required by the caller is derived from the value 4033 * of the symbol. this is simply the relocated value of the 4034 * symbol. 4035 */ 4036 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 4037 sym = make_function_pointer(def, defobj); 4038 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 4039 sym = rtld_resolve_ifunc(defobj, def); 4040 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 4041 ti.ti_module = defobj->tlsindex; 4042 ti.ti_offset = def->st_value; 4043 sym = __tls_get_addr(&ti); 4044 } else 4045 sym = defobj->relocbase + def->st_value; 4046 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 4047 return (sym); 4048 } 4049 4050 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "", 4051 ve != NULL ? ve->name : ""); 4052 lock_release(rtld_bind_lock, &lockstate); 4053 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 4054 return (NULL); 4055 } 4056 4057 void * 4058 dlsym(void *handle, const char *name) 4059 { 4060 return (do_dlsym(handle, name, __builtin_return_address(0), NULL, 4061 SYMLOOK_DLSYM)); 4062 } 4063 4064 dlfunc_t 4065 dlfunc(void *handle, const char *name) 4066 { 4067 union { 4068 void *d; 4069 dlfunc_t f; 4070 } rv; 4071 4072 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 4073 SYMLOOK_DLSYM); 4074 return (rv.f); 4075 } 4076 4077 void * 4078 dlvsym(void *handle, const char *name, const char *version) 4079 { 4080 Ver_Entry ventry; 4081 4082 ventry.name = version; 4083 ventry.file = NULL; 4084 ventry.hash = elf_hash(version); 4085 ventry.flags= 0; 4086 return (do_dlsym(handle, name, __builtin_return_address(0), &ventry, 4087 SYMLOOK_DLSYM)); 4088 } 4089 4090 int 4091 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 4092 { 4093 const Obj_Entry *obj; 4094 RtldLockState lockstate; 4095 4096 rlock_acquire(rtld_bind_lock, &lockstate); 4097 obj = obj_from_addr(addr); 4098 if (obj == NULL) { 4099 _rtld_error("No shared object contains address"); 4100 lock_release(rtld_bind_lock, &lockstate); 4101 return (0); 4102 } 4103 rtld_fill_dl_phdr_info(obj, phdr_info); 4104 lock_release(rtld_bind_lock, &lockstate); 4105 return (1); 4106 } 4107 4108 int 4109 dladdr(const void *addr, Dl_info *info) 4110 { 4111 const Obj_Entry *obj; 4112 const Elf_Sym *def; 4113 void *symbol_addr; 4114 unsigned long symoffset; 4115 RtldLockState lockstate; 4116 4117 rlock_acquire(rtld_bind_lock, &lockstate); 4118 obj = obj_from_addr(addr); 4119 if (obj == NULL) { 4120 _rtld_error("No shared object contains address"); 4121 lock_release(rtld_bind_lock, &lockstate); 4122 return (0); 4123 } 4124 info->dli_fname = obj->path; 4125 info->dli_fbase = obj->mapbase; 4126 info->dli_saddr = (void *)0; 4127 info->dli_sname = NULL; 4128 4129 /* 4130 * Walk the symbol list looking for the symbol whose address is 4131 * closest to the address sent in. 4132 */ 4133 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 4134 def = obj->symtab + symoffset; 4135 4136 /* 4137 * For skip the symbol if st_shndx is either SHN_UNDEF or 4138 * SHN_COMMON. 4139 */ 4140 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 4141 continue; 4142 4143 /* 4144 * If the symbol is greater than the specified address, or if it 4145 * is further away from addr than the current nearest symbol, 4146 * then reject it. 4147 */ 4148 symbol_addr = obj->relocbase + def->st_value; 4149 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 4150 continue; 4151 4152 /* Update our idea of the nearest symbol. */ 4153 info->dli_sname = obj->strtab + def->st_name; 4154 info->dli_saddr = symbol_addr; 4155 4156 /* Exact match? */ 4157 if (info->dli_saddr == addr) 4158 break; 4159 } 4160 lock_release(rtld_bind_lock, &lockstate); 4161 return (1); 4162 } 4163 4164 int 4165 dlinfo(void *handle, int request, void *p) 4166 { 4167 const Obj_Entry *obj; 4168 RtldLockState lockstate; 4169 int error; 4170 4171 rlock_acquire(rtld_bind_lock, &lockstate); 4172 4173 if (handle == NULL || handle == RTLD_SELF) { 4174 void *retaddr; 4175 4176 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 4177 if ((obj = obj_from_addr(retaddr)) == NULL) 4178 _rtld_error("Cannot determine caller's shared object"); 4179 } else 4180 obj = dlcheck(handle); 4181 4182 if (obj == NULL) { 4183 lock_release(rtld_bind_lock, &lockstate); 4184 return (-1); 4185 } 4186 4187 error = 0; 4188 switch (request) { 4189 case RTLD_DI_LINKMAP: 4190 *((struct link_map const **)p) = &obj->linkmap; 4191 break; 4192 case RTLD_DI_ORIGIN: 4193 error = rtld_dirname(obj->path, p); 4194 break; 4195 4196 case RTLD_DI_SERINFOSIZE: 4197 case RTLD_DI_SERINFO: 4198 error = do_search_info(obj, request, (struct dl_serinfo *)p); 4199 break; 4200 4201 default: 4202 _rtld_error("Invalid request %d passed to dlinfo()", request); 4203 error = -1; 4204 } 4205 4206 lock_release(rtld_bind_lock, &lockstate); 4207 4208 return (error); 4209 } 4210 4211 static void 4212 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 4213 { 4214 uintptr_t **dtvp; 4215 4216 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 4217 phdr_info->dlpi_name = obj->path; 4218 phdr_info->dlpi_phdr = obj->phdr; 4219 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 4220 phdr_info->dlpi_tls_modid = obj->tlsindex; 4221 dtvp = &_tcb_get()->tcb_dtv; 4222 phdr_info->dlpi_tls_data = (char *)tls_get_addr_slow(dtvp, 4223 obj->tlsindex, 0, true) + TLS_DTV_OFFSET; 4224 phdr_info->dlpi_adds = obj_loads; 4225 phdr_info->dlpi_subs = obj_loads - obj_count; 4226 } 4227 4228 int 4229 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 4230 { 4231 struct dl_phdr_info phdr_info; 4232 Obj_Entry *obj, marker; 4233 RtldLockState bind_lockstate, phdr_lockstate; 4234 int error; 4235 4236 init_marker(&marker); 4237 error = 0; 4238 4239 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 4240 wlock_acquire(rtld_bind_lock, &bind_lockstate); 4241 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 4242 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 4243 rtld_fill_dl_phdr_info(obj, &phdr_info); 4244 hold_object(obj); 4245 lock_release(rtld_bind_lock, &bind_lockstate); 4246 4247 error = callback(&phdr_info, sizeof phdr_info, param); 4248 4249 wlock_acquire(rtld_bind_lock, &bind_lockstate); 4250 unhold_object(obj); 4251 obj = globallist_next(&marker); 4252 TAILQ_REMOVE(&obj_list, &marker, next); 4253 if (error != 0) { 4254 lock_release(rtld_bind_lock, &bind_lockstate); 4255 lock_release(rtld_phdr_lock, &phdr_lockstate); 4256 return (error); 4257 } 4258 } 4259 4260 if (error == 0) { 4261 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 4262 lock_release(rtld_bind_lock, &bind_lockstate); 4263 error = callback(&phdr_info, sizeof(phdr_info), param); 4264 } 4265 lock_release(rtld_phdr_lock, &phdr_lockstate); 4266 return (error); 4267 } 4268 4269 static void * 4270 fill_search_info(const char *dir, size_t dirlen, void *param) 4271 { 4272 struct fill_search_info_args *arg; 4273 4274 arg = param; 4275 4276 if (arg->request == RTLD_DI_SERINFOSIZE) { 4277 arg->serinfo->dls_cnt ++; 4278 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 4279 } else { 4280 struct dl_serpath *s_entry; 4281 4282 s_entry = arg->serpath; 4283 s_entry->dls_name = arg->strspace; 4284 s_entry->dls_flags = arg->flags; 4285 4286 strncpy(arg->strspace, dir, dirlen); 4287 arg->strspace[dirlen] = '\0'; 4288 4289 arg->strspace += dirlen + 1; 4290 arg->serpath++; 4291 } 4292 4293 return (NULL); 4294 } 4295 4296 static int 4297 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 4298 { 4299 struct dl_serinfo _info; 4300 struct fill_search_info_args args; 4301 4302 args.request = RTLD_DI_SERINFOSIZE; 4303 args.serinfo = &_info; 4304 4305 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 4306 _info.dls_cnt = 0; 4307 4308 path_enumerate(obj->rpath, fill_search_info, NULL, &args); 4309 path_enumerate(ld_library_path, fill_search_info, NULL, &args); 4310 path_enumerate(obj->runpath, fill_search_info, NULL, &args); 4311 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args); 4312 if (!obj->z_nodeflib) 4313 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args); 4314 4315 4316 if (request == RTLD_DI_SERINFOSIZE) { 4317 info->dls_size = _info.dls_size; 4318 info->dls_cnt = _info.dls_cnt; 4319 return (0); 4320 } 4321 4322 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 4323 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 4324 return (-1); 4325 } 4326 4327 args.request = RTLD_DI_SERINFO; 4328 args.serinfo = info; 4329 args.serpath = &info->dls_serpath[0]; 4330 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 4331 4332 args.flags = LA_SER_RUNPATH; 4333 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL) 4334 return (-1); 4335 4336 args.flags = LA_SER_LIBPATH; 4337 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL) 4338 return (-1); 4339 4340 args.flags = LA_SER_RUNPATH; 4341 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL) 4342 return (-1); 4343 4344 args.flags = LA_SER_CONFIG; 4345 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args) 4346 != NULL) 4347 return (-1); 4348 4349 args.flags = LA_SER_DEFAULT; 4350 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path, 4351 fill_search_info, NULL, &args) != NULL) 4352 return (-1); 4353 return (0); 4354 } 4355 4356 static int 4357 rtld_dirname(const char *path, char *bname) 4358 { 4359 const char *endp; 4360 4361 /* Empty or NULL string gets treated as "." */ 4362 if (path == NULL || *path == '\0') { 4363 bname[0] = '.'; 4364 bname[1] = '\0'; 4365 return (0); 4366 } 4367 4368 /* Strip trailing slashes */ 4369 endp = path + strlen(path) - 1; 4370 while (endp > path && *endp == '/') 4371 endp--; 4372 4373 /* Find the start of the dir */ 4374 while (endp > path && *endp != '/') 4375 endp--; 4376 4377 /* Either the dir is "/" or there are no slashes */ 4378 if (endp == path) { 4379 bname[0] = *endp == '/' ? '/' : '.'; 4380 bname[1] = '\0'; 4381 return (0); 4382 } else { 4383 do { 4384 endp--; 4385 } while (endp > path && *endp == '/'); 4386 } 4387 4388 if (endp - path + 2 > PATH_MAX) 4389 { 4390 _rtld_error("Filename is too long: %s", path); 4391 return(-1); 4392 } 4393 4394 strncpy(bname, path, endp - path + 1); 4395 bname[endp - path + 1] = '\0'; 4396 return (0); 4397 } 4398 4399 static int 4400 rtld_dirname_abs(const char *path, char *base) 4401 { 4402 char *last; 4403 4404 if (realpath(path, base) == NULL) { 4405 _rtld_error("realpath \"%s\" failed (%s)", path, 4406 rtld_strerror(errno)); 4407 return (-1); 4408 } 4409 dbg("%s -> %s", path, base); 4410 last = strrchr(base, '/'); 4411 if (last == NULL) { 4412 _rtld_error("non-abs result from realpath \"%s\"", path); 4413 return (-1); 4414 } 4415 if (last != base) 4416 *last = '\0'; 4417 return (0); 4418 } 4419 4420 static void 4421 linkmap_add(Obj_Entry *obj) 4422 { 4423 struct link_map *l, *prev; 4424 4425 l = &obj->linkmap; 4426 l->l_name = obj->path; 4427 l->l_base = obj->mapbase; 4428 l->l_ld = obj->dynamic; 4429 l->l_addr = obj->relocbase; 4430 4431 if (r_debug.r_map == NULL) { 4432 r_debug.r_map = l; 4433 return; 4434 } 4435 4436 /* 4437 * Scan to the end of the list, but not past the entry for the 4438 * dynamic linker, which we want to keep at the very end. 4439 */ 4440 for (prev = r_debug.r_map; 4441 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 4442 prev = prev->l_next) 4443 ; 4444 4445 /* Link in the new entry. */ 4446 l->l_prev = prev; 4447 l->l_next = prev->l_next; 4448 if (l->l_next != NULL) 4449 l->l_next->l_prev = l; 4450 prev->l_next = l; 4451 } 4452 4453 static void 4454 linkmap_delete(Obj_Entry *obj) 4455 { 4456 struct link_map *l; 4457 4458 l = &obj->linkmap; 4459 if (l->l_prev == NULL) { 4460 if ((r_debug.r_map = l->l_next) != NULL) 4461 l->l_next->l_prev = NULL; 4462 return; 4463 } 4464 4465 if ((l->l_prev->l_next = l->l_next) != NULL) 4466 l->l_next->l_prev = l->l_prev; 4467 } 4468 4469 /* 4470 * Function for the debugger to set a breakpoint on to gain control. 4471 * 4472 * The two parameters allow the debugger to easily find and determine 4473 * what the runtime loader is doing and to whom it is doing it. 4474 * 4475 * When the loadhook trap is hit (r_debug_state, set at program 4476 * initialization), the arguments can be found on the stack: 4477 * 4478 * +8 struct link_map *m 4479 * +4 struct r_debug *rd 4480 * +0 RetAddr 4481 */ 4482 void 4483 r_debug_state(struct r_debug* rd __unused, struct link_map *m __unused) 4484 { 4485 /* 4486 * The following is a hack to force the compiler to emit calls to 4487 * this function, even when optimizing. If the function is empty, 4488 * the compiler is not obliged to emit any code for calls to it, 4489 * even when marked __noinline. However, gdb depends on those 4490 * calls being made. 4491 */ 4492 __compiler_membar(); 4493 } 4494 4495 /* 4496 * A function called after init routines have completed. This can be used to 4497 * break before a program's entry routine is called, and can be used when 4498 * main is not available in the symbol table. 4499 */ 4500 void 4501 _r_debug_postinit(struct link_map *m __unused) 4502 { 4503 4504 /* See r_debug_state(). */ 4505 __compiler_membar(); 4506 } 4507 4508 static void 4509 release_object(Obj_Entry *obj) 4510 { 4511 4512 if (obj->holdcount > 0) { 4513 obj->unholdfree = true; 4514 return; 4515 } 4516 munmap(obj->mapbase, obj->mapsize); 4517 linkmap_delete(obj); 4518 obj_free(obj); 4519 } 4520 4521 /* 4522 * Get address of the pointer variable in the main program. 4523 * Prefer non-weak symbol over the weak one. 4524 */ 4525 static const void ** 4526 get_program_var_addr(const char *name, RtldLockState *lockstate) 4527 { 4528 SymLook req; 4529 DoneList donelist; 4530 4531 symlook_init(&req, name); 4532 req.lockstate = lockstate; 4533 donelist_init(&donelist); 4534 if (symlook_global(&req, &donelist) != 0) 4535 return (NULL); 4536 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 4537 return ((const void **)make_function_pointer(req.sym_out, 4538 req.defobj_out)); 4539 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 4540 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 4541 else 4542 return ((const void **)(req.defobj_out->relocbase + 4543 req.sym_out->st_value)); 4544 } 4545 4546 /* 4547 * Set a pointer variable in the main program to the given value. This 4548 * is used to set key variables such as "environ" before any of the 4549 * init functions are called. 4550 */ 4551 static void 4552 set_program_var(const char *name, const void *value) 4553 { 4554 const void **addr; 4555 4556 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 4557 dbg("\"%s\": *%p <-- %p", name, addr, value); 4558 *addr = value; 4559 } 4560 } 4561 4562 /* 4563 * Search the global objects, including dependencies and main object, 4564 * for the given symbol. 4565 */ 4566 static int 4567 symlook_global(SymLook *req, DoneList *donelist) 4568 { 4569 SymLook req1; 4570 const Objlist_Entry *elm; 4571 int res; 4572 4573 symlook_init_from_req(&req1, req); 4574 4575 /* Search all objects loaded at program start up. */ 4576 if (req->defobj_out == NULL || (ld_dynamic_weak && 4577 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK)) { 4578 res = symlook_list(&req1, &list_main, donelist); 4579 if (res == 0 && (!ld_dynamic_weak || req->defobj_out == NULL || 4580 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4581 req->sym_out = req1.sym_out; 4582 req->defobj_out = req1.defobj_out; 4583 assert(req->defobj_out != NULL); 4584 } 4585 } 4586 4587 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 4588 STAILQ_FOREACH(elm, &list_global, link) { 4589 if (req->defobj_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->defobj_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 return (req->sym_out != NULL ? 0 : ESRCH); 4602 } 4603 4604 /* 4605 * Given a symbol name in a referencing object, find the corresponding 4606 * definition of the symbol. Returns a pointer to the symbol, or NULL if 4607 * no definition was found. Returns a pointer to the Obj_Entry of the 4608 * defining object via the reference parameter DEFOBJ_OUT. 4609 */ 4610 static int 4611 symlook_default(SymLook *req, const Obj_Entry *refobj) 4612 { 4613 DoneList donelist; 4614 const Objlist_Entry *elm; 4615 SymLook req1; 4616 int res; 4617 4618 donelist_init(&donelist); 4619 symlook_init_from_req(&req1, req); 4620 4621 /* 4622 * Look first in the referencing object if linked symbolically, 4623 * and similarly handle protected symbols. 4624 */ 4625 res = symlook_obj(&req1, refobj); 4626 if (res == 0 && (refobj->symbolic || 4627 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) { 4628 req->sym_out = req1.sym_out; 4629 req->defobj_out = req1.defobj_out; 4630 assert(req->defobj_out != NULL); 4631 } 4632 if (refobj->symbolic || req->defobj_out != NULL) 4633 donelist_check(&donelist, refobj); 4634 4635 if (!refobj->deepbind) 4636 symlook_global(req, &donelist); 4637 4638 /* Search all dlopened DAGs containing the referencing object. */ 4639 STAILQ_FOREACH(elm, &refobj->dldags, link) { 4640 if (req->sym_out != NULL && (!ld_dynamic_weak || 4641 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)) 4642 break; 4643 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 4644 if (res == 0 && (req->sym_out == NULL || 4645 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4646 req->sym_out = req1.sym_out; 4647 req->defobj_out = req1.defobj_out; 4648 assert(req->defobj_out != NULL); 4649 } 4650 } 4651 4652 if (refobj->deepbind) 4653 symlook_global(req, &donelist); 4654 4655 /* 4656 * Search the dynamic linker itself, and possibly resolve the 4657 * symbol from there. This is how the application links to 4658 * dynamic linker services such as dlopen. 4659 */ 4660 if (req->sym_out == NULL || 4661 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4662 res = symlook_obj(&req1, &obj_rtld); 4663 if (res == 0) { 4664 req->sym_out = req1.sym_out; 4665 req->defobj_out = req1.defobj_out; 4666 assert(req->defobj_out != NULL); 4667 } 4668 } 4669 4670 return (req->sym_out != NULL ? 0 : ESRCH); 4671 } 4672 4673 static int 4674 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 4675 { 4676 const Elf_Sym *def; 4677 const Obj_Entry *defobj; 4678 const Objlist_Entry *elm; 4679 SymLook req1; 4680 int res; 4681 4682 def = NULL; 4683 defobj = NULL; 4684 STAILQ_FOREACH(elm, objlist, link) { 4685 if (donelist_check(dlp, elm->obj)) 4686 continue; 4687 symlook_init_from_req(&req1, req); 4688 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 4689 if (def == NULL || (ld_dynamic_weak && 4690 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4691 def = req1.sym_out; 4692 defobj = req1.defobj_out; 4693 if (!ld_dynamic_weak || ELF_ST_BIND(def->st_info) != STB_WEAK) 4694 break; 4695 } 4696 } 4697 } 4698 if (def != NULL) { 4699 req->sym_out = def; 4700 req->defobj_out = defobj; 4701 return (0); 4702 } 4703 return (ESRCH); 4704 } 4705 4706 /* 4707 * Search the chain of DAGS cointed to by the given Needed_Entry 4708 * for a symbol of the given name. Each DAG is scanned completely 4709 * before advancing to the next one. Returns a pointer to the symbol, 4710 * or NULL if no definition was found. 4711 */ 4712 static int 4713 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 4714 { 4715 const Elf_Sym *def; 4716 const Needed_Entry *n; 4717 const Obj_Entry *defobj; 4718 SymLook req1; 4719 int res; 4720 4721 def = NULL; 4722 defobj = NULL; 4723 symlook_init_from_req(&req1, req); 4724 for (n = needed; n != NULL; n = n->next) { 4725 if (n->obj == NULL || 4726 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 4727 continue; 4728 if (def == NULL || (ld_dynamic_weak && 4729 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4730 def = req1.sym_out; 4731 defobj = req1.defobj_out; 4732 if (!ld_dynamic_weak || ELF_ST_BIND(def->st_info) != STB_WEAK) 4733 break; 4734 } 4735 } 4736 if (def != NULL) { 4737 req->sym_out = def; 4738 req->defobj_out = defobj; 4739 return (0); 4740 } 4741 return (ESRCH); 4742 } 4743 4744 static int 4745 symlook_obj_load_filtees(SymLook *req, SymLook *req1, const Obj_Entry *obj, 4746 Needed_Entry *needed) 4747 { 4748 DoneList donelist; 4749 int flags; 4750 4751 flags = (req->flags & SYMLOOK_EARLY) != 0 ? RTLD_LO_EARLY : 0; 4752 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4753 donelist_init(&donelist); 4754 symlook_init_from_req(req1, req); 4755 return (symlook_needed(req1, needed, &donelist)); 4756 } 4757 4758 /* 4759 * Search the symbol table of a single shared object for a symbol of 4760 * the given name and version, if requested. Returns a pointer to the 4761 * symbol, or NULL if no definition was found. If the object is 4762 * filter, return filtered symbol from filtee. 4763 * 4764 * The symbol's hash value is passed in for efficiency reasons; that 4765 * eliminates many recomputations of the hash value. 4766 */ 4767 int 4768 symlook_obj(SymLook *req, const Obj_Entry *obj) 4769 { 4770 SymLook req1; 4771 int res, mres; 4772 4773 /* 4774 * If there is at least one valid hash at this point, we prefer to 4775 * use the faster GNU version if available. 4776 */ 4777 if (obj->valid_hash_gnu) 4778 mres = symlook_obj1_gnu(req, obj); 4779 else if (obj->valid_hash_sysv) 4780 mres = symlook_obj1_sysv(req, obj); 4781 else 4782 return (EINVAL); 4783 4784 if (mres == 0) { 4785 if (obj->needed_filtees != NULL) { 4786 res = symlook_obj_load_filtees(req, &req1, obj, 4787 obj->needed_filtees); 4788 if (res == 0) { 4789 req->sym_out = req1.sym_out; 4790 req->defobj_out = req1.defobj_out; 4791 } 4792 return (res); 4793 } 4794 if (obj->needed_aux_filtees != NULL) { 4795 res = symlook_obj_load_filtees(req, &req1, obj, 4796 obj->needed_aux_filtees); 4797 if (res == 0) { 4798 req->sym_out = req1.sym_out; 4799 req->defobj_out = req1.defobj_out; 4800 return (res); 4801 } 4802 } 4803 } 4804 return (mres); 4805 } 4806 4807 /* Symbol match routine common to both hash functions */ 4808 static bool 4809 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4810 const unsigned long symnum) 4811 { 4812 Elf_Versym verndx; 4813 const Elf_Sym *symp; 4814 const char *strp; 4815 4816 symp = obj->symtab + symnum; 4817 strp = obj->strtab + symp->st_name; 4818 4819 switch (ELF_ST_TYPE(symp->st_info)) { 4820 case STT_FUNC: 4821 case STT_NOTYPE: 4822 case STT_OBJECT: 4823 case STT_COMMON: 4824 case STT_GNU_IFUNC: 4825 if (symp->st_value == 0) 4826 return (false); 4827 /* fallthrough */ 4828 case STT_TLS: 4829 if (symp->st_shndx != SHN_UNDEF) 4830 break; 4831 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4832 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4833 break; 4834 /* fallthrough */ 4835 default: 4836 return (false); 4837 } 4838 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4839 return (false); 4840 4841 if (req->ventry == NULL) { 4842 if (obj->versyms != NULL) { 4843 verndx = VER_NDX(obj->versyms[symnum]); 4844 if (verndx > obj->vernum) { 4845 _rtld_error( 4846 "%s: symbol %s references wrong version %d", 4847 obj->path, obj->strtab + symnum, verndx); 4848 return (false); 4849 } 4850 /* 4851 * If we are not called from dlsym (i.e. this 4852 * is a normal relocation from unversioned 4853 * binary), accept the symbol immediately if 4854 * it happens to have first version after this 4855 * shared object became versioned. Otherwise, 4856 * if symbol is versioned and not hidden, 4857 * remember it. If it is the only symbol with 4858 * this name exported by the shared object, it 4859 * will be returned as a match by the calling 4860 * function. If symbol is global (verndx < 2) 4861 * accept it unconditionally. 4862 */ 4863 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4864 verndx == VER_NDX_GIVEN) { 4865 result->sym_out = symp; 4866 return (true); 4867 } 4868 else if (verndx >= VER_NDX_GIVEN) { 4869 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4870 == 0) { 4871 if (result->vsymp == NULL) 4872 result->vsymp = symp; 4873 result->vcount++; 4874 } 4875 return (false); 4876 } 4877 } 4878 result->sym_out = symp; 4879 return (true); 4880 } 4881 if (obj->versyms == NULL) { 4882 if (object_match_name(obj, req->ventry->name)) { 4883 _rtld_error("%s: object %s should provide version %s " 4884 "for symbol %s", obj_rtld.path, obj->path, 4885 req->ventry->name, obj->strtab + symnum); 4886 return (false); 4887 } 4888 } else { 4889 verndx = VER_NDX(obj->versyms[symnum]); 4890 if (verndx > obj->vernum) { 4891 _rtld_error("%s: symbol %s references wrong version %d", 4892 obj->path, obj->strtab + symnum, verndx); 4893 return (false); 4894 } 4895 if (obj->vertab[verndx].hash != req->ventry->hash || 4896 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4897 /* 4898 * Version does not match. Look if this is a 4899 * global symbol and if it is not hidden. If 4900 * global symbol (verndx < 2) is available, 4901 * use it. Do not return symbol if we are 4902 * called by dlvsym, because dlvsym looks for 4903 * a specific version and default one is not 4904 * what dlvsym wants. 4905 */ 4906 if ((req->flags & SYMLOOK_DLSYM) || 4907 (verndx >= VER_NDX_GIVEN) || 4908 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4909 return (false); 4910 } 4911 } 4912 result->sym_out = symp; 4913 return (true); 4914 } 4915 4916 /* 4917 * Search for symbol using SysV hash function. 4918 * obj->buckets is known not to be NULL at this point; the test for this was 4919 * performed with the obj->valid_hash_sysv assignment. 4920 */ 4921 static int 4922 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4923 { 4924 unsigned long symnum; 4925 Sym_Match_Result matchres; 4926 4927 matchres.sym_out = NULL; 4928 matchres.vsymp = NULL; 4929 matchres.vcount = 0; 4930 4931 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4932 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4933 if (symnum >= obj->nchains) 4934 return (ESRCH); /* Bad object */ 4935 4936 if (matched_symbol(req, obj, &matchres, symnum)) { 4937 req->sym_out = matchres.sym_out; 4938 req->defobj_out = obj; 4939 return (0); 4940 } 4941 } 4942 if (matchres.vcount == 1) { 4943 req->sym_out = matchres.vsymp; 4944 req->defobj_out = obj; 4945 return (0); 4946 } 4947 return (ESRCH); 4948 } 4949 4950 /* Search for symbol using GNU hash function */ 4951 static int 4952 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4953 { 4954 Elf_Addr bloom_word; 4955 const Elf32_Word *hashval; 4956 Elf32_Word bucket; 4957 Sym_Match_Result matchres; 4958 unsigned int h1, h2; 4959 unsigned long symnum; 4960 4961 matchres.sym_out = NULL; 4962 matchres.vsymp = NULL; 4963 matchres.vcount = 0; 4964 4965 /* Pick right bitmask word from Bloom filter array */ 4966 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4967 obj->maskwords_bm_gnu]; 4968 4969 /* Calculate modulus word size of gnu hash and its derivative */ 4970 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4971 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4972 4973 /* Filter out the "definitely not in set" queries */ 4974 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4975 return (ESRCH); 4976 4977 /* Locate hash chain and corresponding value element*/ 4978 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4979 if (bucket == 0) 4980 return (ESRCH); 4981 hashval = &obj->chain_zero_gnu[bucket]; 4982 do { 4983 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4984 symnum = hashval - obj->chain_zero_gnu; 4985 if (matched_symbol(req, obj, &matchres, symnum)) { 4986 req->sym_out = matchres.sym_out; 4987 req->defobj_out = obj; 4988 return (0); 4989 } 4990 } 4991 } while ((*hashval++ & 1) == 0); 4992 if (matchres.vcount == 1) { 4993 req->sym_out = matchres.vsymp; 4994 req->defobj_out = obj; 4995 return (0); 4996 } 4997 return (ESRCH); 4998 } 4999 5000 static void 5001 trace_calc_fmts(const char **main_local, const char **fmt1, const char **fmt2) 5002 { 5003 *main_local = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_PROGNAME); 5004 if (*main_local == NULL) 5005 *main_local = ""; 5006 5007 *fmt1 = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT1); 5008 if (*fmt1 == NULL) 5009 *fmt1 = "\t%o => %p (%x)\n"; 5010 5011 *fmt2 = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT2); 5012 if (*fmt2 == NULL) 5013 *fmt2 = "\t%o (%x)\n"; 5014 } 5015 5016 static void 5017 trace_print_obj(Obj_Entry *obj, const char *name, const char *path, 5018 const char *main_local, const char *fmt1, const char *fmt2) 5019 { 5020 const char *fmt; 5021 int c; 5022 5023 if (fmt1 == NULL) 5024 fmt = fmt2; 5025 else 5026 /* XXX bogus */ 5027 fmt = strncmp(name, "lib", 3) == 0 ? fmt1 : fmt2; 5028 5029 while ((c = *fmt++) != '\0') { 5030 switch (c) { 5031 default: 5032 rtld_putchar(c); 5033 continue; 5034 case '\\': 5035 switch (c = *fmt) { 5036 case '\0': 5037 continue; 5038 case 'n': 5039 rtld_putchar('\n'); 5040 break; 5041 case 't': 5042 rtld_putchar('\t'); 5043 break; 5044 } 5045 break; 5046 case '%': 5047 switch (c = *fmt) { 5048 case '\0': 5049 continue; 5050 case '%': 5051 default: 5052 rtld_putchar(c); 5053 break; 5054 case 'A': 5055 rtld_putstr(main_local); 5056 break; 5057 case 'a': 5058 rtld_putstr(obj_main->path); 5059 break; 5060 case 'o': 5061 rtld_putstr(name); 5062 break; 5063 case 'p': 5064 rtld_putstr(path); 5065 break; 5066 case 'x': 5067 rtld_printf("%p", obj != NULL ? 5068 obj->mapbase : NULL); 5069 break; 5070 } 5071 break; 5072 } 5073 ++fmt; 5074 } 5075 } 5076 5077 static void 5078 trace_loaded_objects(Obj_Entry *obj, bool show_preload) 5079 { 5080 const char *fmt1, *fmt2, *main_local; 5081 const char *name, *path; 5082 bool first_spurious, list_containers; 5083 5084 trace_calc_fmts(&main_local, &fmt1, &fmt2); 5085 list_containers = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_ALL) != NULL; 5086 5087 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 5088 Needed_Entry *needed; 5089 5090 if (obj->marker) 5091 continue; 5092 if (list_containers && obj->needed != NULL) 5093 rtld_printf("%s:\n", obj->path); 5094 for (needed = obj->needed; needed; needed = needed->next) { 5095 if (needed->obj != NULL) { 5096 if (needed->obj->traced && !list_containers) 5097 continue; 5098 needed->obj->traced = true; 5099 path = needed->obj->path; 5100 } else 5101 path = "not found"; 5102 5103 name = obj->strtab + needed->name; 5104 trace_print_obj(needed->obj, name, path, main_local, 5105 fmt1, fmt2); 5106 } 5107 } 5108 5109 if (show_preload) { 5110 if (ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT2) == NULL) 5111 fmt2 = "\t%p (%x)\n"; 5112 first_spurious = true; 5113 5114 TAILQ_FOREACH(obj, &obj_list, next) { 5115 if (obj->marker || obj == obj_main || obj->traced) 5116 continue; 5117 5118 if (list_containers && first_spurious) { 5119 rtld_printf("[preloaded]\n"); 5120 first_spurious = false; 5121 } 5122 5123 Name_Entry *fname = STAILQ_FIRST(&obj->names); 5124 name = fname == NULL ? "<unknown>" : fname->name; 5125 trace_print_obj(obj, name, obj->path, main_local, 5126 NULL, fmt2); 5127 } 5128 } 5129 } 5130 5131 /* 5132 * Unload a dlopened object and its dependencies from memory and from 5133 * our data structures. It is assumed that the DAG rooted in the 5134 * object has already been unreferenced, and that the object has a 5135 * reference count of 0. 5136 */ 5137 static void 5138 unload_object(Obj_Entry *root, RtldLockState *lockstate) 5139 { 5140 Obj_Entry marker, *obj, *next; 5141 5142 assert(root->refcount == 0); 5143 5144 /* 5145 * Pass over the DAG removing unreferenced objects from 5146 * appropriate lists. 5147 */ 5148 unlink_object(root); 5149 5150 /* Unmap all objects that are no longer referenced. */ 5151 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) { 5152 next = TAILQ_NEXT(obj, next); 5153 if (obj->marker || obj->refcount != 0) 5154 continue; 5155 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 5156 obj->mapsize, 0, obj->path); 5157 dbg("unloading \"%s\"", obj->path); 5158 /* 5159 * Unlink the object now to prevent new references from 5160 * being acquired while the bind lock is dropped in 5161 * recursive dlclose() invocations. 5162 */ 5163 TAILQ_REMOVE(&obj_list, obj, next); 5164 obj_count--; 5165 5166 if (obj->filtees_loaded) { 5167 if (next != NULL) { 5168 init_marker(&marker); 5169 TAILQ_INSERT_BEFORE(next, &marker, next); 5170 unload_filtees(obj, lockstate); 5171 next = TAILQ_NEXT(&marker, next); 5172 TAILQ_REMOVE(&obj_list, &marker, next); 5173 } else 5174 unload_filtees(obj, lockstate); 5175 } 5176 release_object(obj); 5177 } 5178 } 5179 5180 static void 5181 unlink_object(Obj_Entry *root) 5182 { 5183 Objlist_Entry *elm; 5184 5185 if (root->refcount == 0) { 5186 /* Remove the object from the RTLD_GLOBAL list. */ 5187 objlist_remove(&list_global, root); 5188 5189 /* Remove the object from all objects' DAG lists. */ 5190 STAILQ_FOREACH(elm, &root->dagmembers, link) { 5191 objlist_remove(&elm->obj->dldags, root); 5192 if (elm->obj != root) 5193 unlink_object(elm->obj); 5194 } 5195 } 5196 } 5197 5198 static void 5199 ref_dag(Obj_Entry *root) 5200 { 5201 Objlist_Entry *elm; 5202 5203 assert(root->dag_inited); 5204 STAILQ_FOREACH(elm, &root->dagmembers, link) 5205 elm->obj->refcount++; 5206 } 5207 5208 static void 5209 unref_dag(Obj_Entry *root) 5210 { 5211 Objlist_Entry *elm; 5212 5213 assert(root->dag_inited); 5214 STAILQ_FOREACH(elm, &root->dagmembers, link) 5215 elm->obj->refcount--; 5216 } 5217 5218 /* 5219 * Common code for MD __tls_get_addr(). 5220 */ 5221 static void * 5222 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset, bool locked) 5223 { 5224 Elf_Addr *newdtv, *dtv; 5225 RtldLockState lockstate; 5226 int to_copy; 5227 5228 dtv = *dtvp; 5229 /* Check dtv generation in case new modules have arrived */ 5230 if (dtv[0] != tls_dtv_generation) { 5231 if (!locked) 5232 wlock_acquire(rtld_bind_lock, &lockstate); 5233 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5234 to_copy = dtv[1]; 5235 if (to_copy > tls_max_index) 5236 to_copy = tls_max_index; 5237 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 5238 newdtv[0] = tls_dtv_generation; 5239 newdtv[1] = tls_max_index; 5240 free(dtv); 5241 if (!locked) 5242 lock_release(rtld_bind_lock, &lockstate); 5243 dtv = *dtvp = newdtv; 5244 } 5245 5246 /* Dynamically allocate module TLS if necessary */ 5247 if (dtv[index + 1] == 0) { 5248 /* Signal safe, wlock will block out signals. */ 5249 if (!locked) 5250 wlock_acquire(rtld_bind_lock, &lockstate); 5251 if (!dtv[index + 1]) 5252 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 5253 if (!locked) 5254 lock_release(rtld_bind_lock, &lockstate); 5255 } 5256 return ((void *)(dtv[index + 1] + offset)); 5257 } 5258 5259 void * 5260 tls_get_addr_common(uintptr_t **dtvp, int index, size_t offset) 5261 { 5262 uintptr_t *dtv; 5263 5264 dtv = *dtvp; 5265 /* Check dtv generation in case new modules have arrived */ 5266 if (__predict_true(dtv[0] == tls_dtv_generation && 5267 dtv[index + 1] != 0)) 5268 return ((void *)(dtv[index + 1] + offset)); 5269 return (tls_get_addr_slow(dtvp, index, offset, false)); 5270 } 5271 5272 #ifdef TLS_VARIANT_I 5273 5274 /* 5275 * Return pointer to allocated TLS block 5276 */ 5277 static void * 5278 get_tls_block_ptr(void *tcb, size_t tcbsize) 5279 { 5280 size_t extra_size, post_size, pre_size, tls_block_size; 5281 size_t tls_init_align; 5282 5283 tls_init_align = MAX(obj_main->tlsalign, 1); 5284 5285 /* Compute fragments sizes. */ 5286 extra_size = tcbsize - TLS_TCB_SIZE; 5287 post_size = calculate_tls_post_size(tls_init_align); 5288 tls_block_size = tcbsize + post_size; 5289 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 5290 5291 return ((char *)tcb - pre_size - extra_size); 5292 } 5293 5294 /* 5295 * Allocate Static TLS using the Variant I method. 5296 * 5297 * For details on the layout, see lib/libc/gen/tls.c. 5298 * 5299 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as 5300 * it is based on tls_last_offset, and TLS offsets here are really TCB 5301 * offsets, whereas libc's tls_static_space is just the executable's static 5302 * TLS segment. 5303 */ 5304 void * 5305 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 5306 { 5307 Obj_Entry *obj; 5308 char *tls_block; 5309 Elf_Addr *dtv, **tcb; 5310 Elf_Addr addr; 5311 Elf_Addr i; 5312 size_t extra_size, maxalign, post_size, pre_size, tls_block_size; 5313 size_t tls_init_align, tls_init_offset; 5314 5315 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 5316 return (oldtcb); 5317 5318 assert(tcbsize >= TLS_TCB_SIZE); 5319 maxalign = MAX(tcbalign, tls_static_max_align); 5320 tls_init_align = MAX(obj_main->tlsalign, 1); 5321 5322 /* Compute fragmets sizes. */ 5323 extra_size = tcbsize - TLS_TCB_SIZE; 5324 post_size = calculate_tls_post_size(tls_init_align); 5325 tls_block_size = tcbsize + post_size; 5326 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 5327 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size; 5328 5329 /* Allocate whole TLS block */ 5330 tls_block = xmalloc_aligned(tls_block_size, maxalign, 0); 5331 tcb = (Elf_Addr **)(tls_block + pre_size + extra_size); 5332 5333 if (oldtcb != NULL) { 5334 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize), 5335 tls_static_space); 5336 free(get_tls_block_ptr(oldtcb, tcbsize)); 5337 5338 /* Adjust the DTV. */ 5339 dtv = tcb[0]; 5340 for (i = 0; i < dtv[1]; i++) { 5341 if (dtv[i+2] >= (Elf_Addr)oldtcb && 5342 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 5343 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tcb; 5344 } 5345 } 5346 } else { 5347 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5348 tcb[0] = dtv; 5349 dtv[0] = tls_dtv_generation; 5350 dtv[1] = tls_max_index; 5351 5352 for (obj = globallist_curr(objs); obj != NULL; 5353 obj = globallist_next(obj)) { 5354 if (obj->tlsoffset == 0) 5355 continue; 5356 tls_init_offset = obj->tlspoffset & (obj->tlsalign - 1); 5357 addr = (Elf_Addr)tcb + obj->tlsoffset; 5358 if (tls_init_offset > 0) 5359 memset((void *)addr, 0, tls_init_offset); 5360 if (obj->tlsinitsize > 0) { 5361 memcpy((void *)(addr + tls_init_offset), obj->tlsinit, 5362 obj->tlsinitsize); 5363 } 5364 if (obj->tlssize > obj->tlsinitsize) { 5365 memset((void *)(addr + tls_init_offset + obj->tlsinitsize), 5366 0, obj->tlssize - obj->tlsinitsize - tls_init_offset); 5367 } 5368 dtv[obj->tlsindex + 1] = addr; 5369 } 5370 } 5371 5372 return (tcb); 5373 } 5374 5375 void 5376 free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused) 5377 { 5378 Elf_Addr *dtv; 5379 Elf_Addr tlsstart, tlsend; 5380 size_t post_size; 5381 size_t dtvsize, i, tls_init_align __unused; 5382 5383 assert(tcbsize >= TLS_TCB_SIZE); 5384 tls_init_align = MAX(obj_main->tlsalign, 1); 5385 5386 /* Compute fragments sizes. */ 5387 post_size = calculate_tls_post_size(tls_init_align); 5388 5389 tlsstart = (Elf_Addr)tcb + TLS_TCB_SIZE + post_size; 5390 tlsend = (Elf_Addr)tcb + tls_static_space; 5391 5392 dtv = *(Elf_Addr **)tcb; 5393 dtvsize = dtv[1]; 5394 for (i = 0; i < dtvsize; i++) { 5395 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 5396 free((void*)dtv[i+2]); 5397 } 5398 } 5399 free(dtv); 5400 free(get_tls_block_ptr(tcb, tcbsize)); 5401 } 5402 5403 #endif /* TLS_VARIANT_I */ 5404 5405 #ifdef TLS_VARIANT_II 5406 5407 /* 5408 * Allocate Static TLS using the Variant II method. 5409 */ 5410 void * 5411 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 5412 { 5413 Obj_Entry *obj; 5414 size_t size, ralign; 5415 char *tls; 5416 Elf_Addr *dtv, *olddtv; 5417 Elf_Addr segbase, oldsegbase, addr; 5418 size_t i; 5419 5420 ralign = tcbalign; 5421 if (tls_static_max_align > ralign) 5422 ralign = tls_static_max_align; 5423 size = roundup(tls_static_space, ralign) + roundup(tcbsize, ralign); 5424 5425 assert(tcbsize >= 2*sizeof(Elf_Addr)); 5426 tls = xmalloc_aligned(size, ralign, 0 /* XXX */); 5427 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5428 5429 segbase = (Elf_Addr)(tls + roundup(tls_static_space, ralign)); 5430 ((Elf_Addr *)segbase)[0] = segbase; 5431 ((Elf_Addr *)segbase)[1] = (Elf_Addr) dtv; 5432 5433 dtv[0] = tls_dtv_generation; 5434 dtv[1] = tls_max_index; 5435 5436 if (oldtls) { 5437 /* 5438 * Copy the static TLS block over whole. 5439 */ 5440 oldsegbase = (Elf_Addr) oldtls; 5441 memcpy((void *)(segbase - tls_static_space), 5442 (const void *)(oldsegbase - tls_static_space), 5443 tls_static_space); 5444 5445 /* 5446 * If any dynamic TLS blocks have been created tls_get_addr(), 5447 * move them over. 5448 */ 5449 olddtv = ((Elf_Addr **)oldsegbase)[1]; 5450 for (i = 0; i < olddtv[1]; i++) { 5451 if (olddtv[i + 2] < oldsegbase - size || 5452 olddtv[i + 2] > oldsegbase) { 5453 dtv[i + 2] = olddtv[i + 2]; 5454 olddtv[i + 2] = 0; 5455 } 5456 } 5457 5458 /* 5459 * We assume that this block was the one we created with 5460 * allocate_initial_tls(). 5461 */ 5462 free_tls(oldtls, 2 * sizeof(Elf_Addr), sizeof(Elf_Addr)); 5463 } else { 5464 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 5465 if (obj->marker || obj->tlsoffset == 0) 5466 continue; 5467 addr = segbase - obj->tlsoffset; 5468 memset((void *)(addr + obj->tlsinitsize), 5469 0, obj->tlssize - obj->tlsinitsize); 5470 if (obj->tlsinit) { 5471 memcpy((void *)addr, obj->tlsinit, obj->tlsinitsize); 5472 obj->static_tls_copied = true; 5473 } 5474 dtv[obj->tlsindex + 1] = addr; 5475 } 5476 } 5477 5478 return ((void *)segbase); 5479 } 5480 5481 void 5482 free_tls(void *tls, size_t tcbsize __unused, size_t tcbalign) 5483 { 5484 Elf_Addr* dtv; 5485 size_t size, ralign; 5486 int dtvsize, i; 5487 Elf_Addr tlsstart, tlsend; 5488 5489 /* 5490 * Figure out the size of the initial TLS block so that we can 5491 * find stuff which ___tls_get_addr() allocated dynamically. 5492 */ 5493 ralign = tcbalign; 5494 if (tls_static_max_align > ralign) 5495 ralign = tls_static_max_align; 5496 size = roundup(tls_static_space, ralign); 5497 5498 dtv = ((Elf_Addr **)tls)[1]; 5499 dtvsize = dtv[1]; 5500 tlsend = (Elf_Addr)tls; 5501 tlsstart = tlsend - size; 5502 for (i = 0; i < dtvsize; i++) { 5503 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || 5504 dtv[i + 2] > tlsend)) { 5505 free((void *)dtv[i + 2]); 5506 } 5507 } 5508 5509 free((void *)tlsstart); 5510 free((void *)dtv); 5511 } 5512 5513 #endif /* TLS_VARIANT_II */ 5514 5515 /* 5516 * Allocate TLS block for module with given index. 5517 */ 5518 void * 5519 allocate_module_tls(int index) 5520 { 5521 Obj_Entry *obj; 5522 char *p; 5523 5524 TAILQ_FOREACH(obj, &obj_list, next) { 5525 if (obj->marker) 5526 continue; 5527 if (obj->tlsindex == index) 5528 break; 5529 } 5530 if (obj == NULL) { 5531 _rtld_error("Can't find module with TLS index %d", index); 5532 rtld_die(); 5533 } 5534 5535 if (obj->tls_static) { 5536 #ifdef TLS_VARIANT_I 5537 p = (char *)_tcb_get() + obj->tlsoffset + TLS_TCB_SIZE; 5538 #else 5539 p = (char *)_tcb_get() - obj->tlsoffset; 5540 #endif 5541 return (p); 5542 } 5543 5544 obj->tls_dynamic = true; 5545 5546 p = xmalloc_aligned(obj->tlssize, obj->tlsalign, obj->tlspoffset); 5547 memcpy(p, obj->tlsinit, obj->tlsinitsize); 5548 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 5549 return (p); 5550 } 5551 5552 bool 5553 allocate_tls_offset(Obj_Entry *obj) 5554 { 5555 size_t off; 5556 5557 if (obj->tls_dynamic) 5558 return (false); 5559 5560 if (obj->tls_static) 5561 return (true); 5562 5563 if (obj->tlssize == 0) { 5564 obj->tls_static = true; 5565 return (true); 5566 } 5567 5568 if (tls_last_offset == 0) 5569 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign, 5570 obj->tlspoffset); 5571 else 5572 off = calculate_tls_offset(tls_last_offset, tls_last_size, 5573 obj->tlssize, obj->tlsalign, obj->tlspoffset); 5574 5575 obj->tlsoffset = off; 5576 #ifdef TLS_VARIANT_I 5577 off += obj->tlssize; 5578 #endif 5579 5580 /* 5581 * If we have already fixed the size of the static TLS block, we 5582 * must stay within that size. When allocating the static TLS, we 5583 * leave a small amount of space spare to be used for dynamically 5584 * loading modules which use static TLS. 5585 */ 5586 if (tls_static_space != 0) { 5587 if (off > tls_static_space) 5588 return (false); 5589 } else if (obj->tlsalign > tls_static_max_align) { 5590 tls_static_max_align = obj->tlsalign; 5591 } 5592 5593 tls_last_offset = off; 5594 tls_last_size = obj->tlssize; 5595 obj->tls_static = true; 5596 5597 return (true); 5598 } 5599 5600 void 5601 free_tls_offset(Obj_Entry *obj) 5602 { 5603 5604 /* 5605 * If we were the last thing to allocate out of the static TLS 5606 * block, we give our space back to the 'allocator'. This is a 5607 * simplistic workaround to allow libGL.so.1 to be loaded and 5608 * unloaded multiple times. 5609 */ 5610 size_t off = obj->tlsoffset; 5611 #ifdef TLS_VARIANT_I 5612 off += obj->tlssize; 5613 #endif 5614 if (off == tls_last_offset) { 5615 tls_last_offset -= obj->tlssize; 5616 tls_last_size = 0; 5617 } 5618 } 5619 5620 void * 5621 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 5622 { 5623 void *ret; 5624 RtldLockState lockstate; 5625 5626 wlock_acquire(rtld_bind_lock, &lockstate); 5627 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 5628 tcbsize, tcbalign); 5629 lock_release(rtld_bind_lock, &lockstate); 5630 return (ret); 5631 } 5632 5633 void 5634 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 5635 { 5636 RtldLockState lockstate; 5637 5638 wlock_acquire(rtld_bind_lock, &lockstate); 5639 free_tls(tcb, tcbsize, tcbalign); 5640 lock_release(rtld_bind_lock, &lockstate); 5641 } 5642 5643 static void 5644 object_add_name(Obj_Entry *obj, const char *name) 5645 { 5646 Name_Entry *entry; 5647 size_t len; 5648 5649 len = strlen(name); 5650 entry = malloc(sizeof(Name_Entry) + len); 5651 5652 if (entry != NULL) { 5653 strcpy(entry->name, name); 5654 STAILQ_INSERT_TAIL(&obj->names, entry, link); 5655 } 5656 } 5657 5658 static int 5659 object_match_name(const Obj_Entry *obj, const char *name) 5660 { 5661 Name_Entry *entry; 5662 5663 STAILQ_FOREACH(entry, &obj->names, link) { 5664 if (strcmp(name, entry->name) == 0) 5665 return (1); 5666 } 5667 return (0); 5668 } 5669 5670 static Obj_Entry * 5671 locate_dependency(const Obj_Entry *obj, const char *name) 5672 { 5673 const Objlist_Entry *entry; 5674 const Needed_Entry *needed; 5675 5676 STAILQ_FOREACH(entry, &list_main, link) { 5677 if (object_match_name(entry->obj, name)) 5678 return (entry->obj); 5679 } 5680 5681 for (needed = obj->needed; needed != NULL; needed = needed->next) { 5682 if (strcmp(obj->strtab + needed->name, name) == 0 || 5683 (needed->obj != NULL && object_match_name(needed->obj, name))) { 5684 /* 5685 * If there is DT_NEEDED for the name we are looking for, 5686 * we are all set. Note that object might not be found if 5687 * dependency was not loaded yet, so the function can 5688 * return NULL here. This is expected and handled 5689 * properly by the caller. 5690 */ 5691 return (needed->obj); 5692 } 5693 } 5694 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 5695 obj->path, name); 5696 rtld_die(); 5697 } 5698 5699 static int 5700 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 5701 const Elf_Vernaux *vna) 5702 { 5703 const Elf_Verdef *vd; 5704 const char *vername; 5705 5706 vername = refobj->strtab + vna->vna_name; 5707 vd = depobj->verdef; 5708 if (vd == NULL) { 5709 _rtld_error("%s: version %s required by %s not defined", 5710 depobj->path, vername, refobj->path); 5711 return (-1); 5712 } 5713 for (;;) { 5714 if (vd->vd_version != VER_DEF_CURRENT) { 5715 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5716 depobj->path, vd->vd_version); 5717 return (-1); 5718 } 5719 if (vna->vna_hash == vd->vd_hash) { 5720 const Elf_Verdaux *aux = (const Elf_Verdaux *) 5721 ((const char *)vd + vd->vd_aux); 5722 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 5723 return (0); 5724 } 5725 if (vd->vd_next == 0) 5726 break; 5727 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5728 } 5729 if (vna->vna_flags & VER_FLG_WEAK) 5730 return (0); 5731 _rtld_error("%s: version %s required by %s not found", 5732 depobj->path, vername, refobj->path); 5733 return (-1); 5734 } 5735 5736 static int 5737 rtld_verify_object_versions(Obj_Entry *obj) 5738 { 5739 const Elf_Verneed *vn; 5740 const Elf_Verdef *vd; 5741 const Elf_Verdaux *vda; 5742 const Elf_Vernaux *vna; 5743 const Obj_Entry *depobj; 5744 int maxvernum, vernum; 5745 5746 if (obj->ver_checked) 5747 return (0); 5748 obj->ver_checked = true; 5749 5750 maxvernum = 0; 5751 /* 5752 * Walk over defined and required version records and figure out 5753 * max index used by any of them. Do very basic sanity checking 5754 * while there. 5755 */ 5756 vn = obj->verneed; 5757 while (vn != NULL) { 5758 if (vn->vn_version != VER_NEED_CURRENT) { 5759 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 5760 obj->path, vn->vn_version); 5761 return (-1); 5762 } 5763 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5764 for (;;) { 5765 vernum = VER_NEED_IDX(vna->vna_other); 5766 if (vernum > maxvernum) 5767 maxvernum = vernum; 5768 if (vna->vna_next == 0) 5769 break; 5770 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5771 } 5772 if (vn->vn_next == 0) 5773 break; 5774 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5775 } 5776 5777 vd = obj->verdef; 5778 while (vd != NULL) { 5779 if (vd->vd_version != VER_DEF_CURRENT) { 5780 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5781 obj->path, vd->vd_version); 5782 return (-1); 5783 } 5784 vernum = VER_DEF_IDX(vd->vd_ndx); 5785 if (vernum > maxvernum) 5786 maxvernum = vernum; 5787 if (vd->vd_next == 0) 5788 break; 5789 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5790 } 5791 5792 if (maxvernum == 0) 5793 return (0); 5794 5795 /* 5796 * Store version information in array indexable by version index. 5797 * Verify that object version requirements are satisfied along the 5798 * way. 5799 */ 5800 obj->vernum = maxvernum + 1; 5801 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 5802 5803 vd = obj->verdef; 5804 while (vd != NULL) { 5805 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 5806 vernum = VER_DEF_IDX(vd->vd_ndx); 5807 assert(vernum <= maxvernum); 5808 vda = (const Elf_Verdaux *)((const char *)vd + vd->vd_aux); 5809 obj->vertab[vernum].hash = vd->vd_hash; 5810 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 5811 obj->vertab[vernum].file = NULL; 5812 obj->vertab[vernum].flags = 0; 5813 } 5814 if (vd->vd_next == 0) 5815 break; 5816 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5817 } 5818 5819 vn = obj->verneed; 5820 while (vn != NULL) { 5821 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 5822 if (depobj == NULL) 5823 return (-1); 5824 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5825 for (;;) { 5826 if (check_object_provided_version(obj, depobj, vna)) 5827 return (-1); 5828 vernum = VER_NEED_IDX(vna->vna_other); 5829 assert(vernum <= maxvernum); 5830 obj->vertab[vernum].hash = vna->vna_hash; 5831 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 5832 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 5833 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 5834 VER_INFO_HIDDEN : 0; 5835 if (vna->vna_next == 0) 5836 break; 5837 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5838 } 5839 if (vn->vn_next == 0) 5840 break; 5841 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5842 } 5843 return (0); 5844 } 5845 5846 static int 5847 rtld_verify_versions(const Objlist *objlist) 5848 { 5849 Objlist_Entry *entry; 5850 int rc; 5851 5852 rc = 0; 5853 STAILQ_FOREACH(entry, objlist, link) { 5854 /* 5855 * Skip dummy objects or objects that have their version requirements 5856 * already checked. 5857 */ 5858 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 5859 continue; 5860 if (rtld_verify_object_versions(entry->obj) == -1) { 5861 rc = -1; 5862 if (ld_tracing == NULL) 5863 break; 5864 } 5865 } 5866 if (rc == 0 || ld_tracing != NULL) 5867 rc = rtld_verify_object_versions(&obj_rtld); 5868 return (rc); 5869 } 5870 5871 const Ver_Entry * 5872 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 5873 { 5874 Elf_Versym vernum; 5875 5876 if (obj->vertab) { 5877 vernum = VER_NDX(obj->versyms[symnum]); 5878 if (vernum >= obj->vernum) { 5879 _rtld_error("%s: symbol %s has wrong verneed value %d", 5880 obj->path, obj->strtab + symnum, vernum); 5881 } else if (obj->vertab[vernum].hash != 0) { 5882 return (&obj->vertab[vernum]); 5883 } 5884 } 5885 return (NULL); 5886 } 5887 5888 int 5889 _rtld_get_stack_prot(void) 5890 { 5891 5892 return (stack_prot); 5893 } 5894 5895 int 5896 _rtld_is_dlopened(void *arg) 5897 { 5898 Obj_Entry *obj; 5899 RtldLockState lockstate; 5900 int res; 5901 5902 rlock_acquire(rtld_bind_lock, &lockstate); 5903 obj = dlcheck(arg); 5904 if (obj == NULL) 5905 obj = obj_from_addr(arg); 5906 if (obj == NULL) { 5907 _rtld_error("No shared object contains address"); 5908 lock_release(rtld_bind_lock, &lockstate); 5909 return (-1); 5910 } 5911 res = obj->dlopened ? 1 : 0; 5912 lock_release(rtld_bind_lock, &lockstate); 5913 return (res); 5914 } 5915 5916 static int 5917 obj_remap_relro(Obj_Entry *obj, int prot) 5918 { 5919 5920 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size, 5921 prot) == -1) { 5922 _rtld_error("%s: Cannot set relro protection to %#x: %s", 5923 obj->path, prot, rtld_strerror(errno)); 5924 return (-1); 5925 } 5926 return (0); 5927 } 5928 5929 static int 5930 obj_disable_relro(Obj_Entry *obj) 5931 { 5932 5933 return (obj_remap_relro(obj, PROT_READ | PROT_WRITE)); 5934 } 5935 5936 static int 5937 obj_enforce_relro(Obj_Entry *obj) 5938 { 5939 5940 return (obj_remap_relro(obj, PROT_READ)); 5941 } 5942 5943 static void 5944 map_stacks_exec(RtldLockState *lockstate) 5945 { 5946 void (*thr_map_stacks_exec)(void); 5947 5948 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5949 return; 5950 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5951 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5952 if (thr_map_stacks_exec != NULL) { 5953 stack_prot |= PROT_EXEC; 5954 thr_map_stacks_exec(); 5955 } 5956 } 5957 5958 static void 5959 distribute_static_tls(Objlist *list, RtldLockState *lockstate) 5960 { 5961 Objlist_Entry *elm; 5962 Obj_Entry *obj; 5963 void (*distrib)(size_t, void *, size_t, size_t); 5964 5965 distrib = (void (*)(size_t, void *, size_t, size_t))(uintptr_t) 5966 get_program_var_addr("__pthread_distribute_static_tls", lockstate); 5967 if (distrib == NULL) 5968 return; 5969 STAILQ_FOREACH(elm, list, link) { 5970 obj = elm->obj; 5971 if (obj->marker || !obj->tls_static || obj->static_tls_copied) 5972 continue; 5973 lock_release(rtld_bind_lock, lockstate); 5974 distrib(obj->tlsoffset, obj->tlsinit, obj->tlsinitsize, 5975 obj->tlssize); 5976 wlock_acquire(rtld_bind_lock, lockstate); 5977 obj->static_tls_copied = true; 5978 } 5979 } 5980 5981 void 5982 symlook_init(SymLook *dst, const char *name) 5983 { 5984 5985 bzero(dst, sizeof(*dst)); 5986 dst->name = name; 5987 dst->hash = elf_hash(name); 5988 dst->hash_gnu = gnu_hash(name); 5989 } 5990 5991 static void 5992 symlook_init_from_req(SymLook *dst, const SymLook *src) 5993 { 5994 5995 dst->name = src->name; 5996 dst->hash = src->hash; 5997 dst->hash_gnu = src->hash_gnu; 5998 dst->ventry = src->ventry; 5999 dst->flags = src->flags; 6000 dst->defobj_out = NULL; 6001 dst->sym_out = NULL; 6002 dst->lockstate = src->lockstate; 6003 } 6004 6005 static int 6006 open_binary_fd(const char *argv0, bool search_in_path, 6007 const char **binpath_res) 6008 { 6009 char *binpath, *pathenv, *pe, *res1; 6010 const char *res; 6011 int fd; 6012 6013 binpath = NULL; 6014 res = NULL; 6015 if (search_in_path && strchr(argv0, '/') == NULL) { 6016 binpath = xmalloc(PATH_MAX); 6017 pathenv = getenv("PATH"); 6018 if (pathenv == NULL) { 6019 _rtld_error("-p and no PATH environment variable"); 6020 rtld_die(); 6021 } 6022 pathenv = strdup(pathenv); 6023 if (pathenv == NULL) { 6024 _rtld_error("Cannot allocate memory"); 6025 rtld_die(); 6026 } 6027 fd = -1; 6028 errno = ENOENT; 6029 while ((pe = strsep(&pathenv, ":")) != NULL) { 6030 if (strlcpy(binpath, pe, PATH_MAX) >= PATH_MAX) 6031 continue; 6032 if (binpath[0] != '\0' && 6033 strlcat(binpath, "/", PATH_MAX) >= PATH_MAX) 6034 continue; 6035 if (strlcat(binpath, argv0, PATH_MAX) >= PATH_MAX) 6036 continue; 6037 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY); 6038 if (fd != -1 || errno != ENOENT) { 6039 res = binpath; 6040 break; 6041 } 6042 } 6043 free(pathenv); 6044 } else { 6045 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY); 6046 res = argv0; 6047 } 6048 6049 if (fd == -1) { 6050 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno)); 6051 rtld_die(); 6052 } 6053 if (res != NULL && res[0] != '/') { 6054 res1 = xmalloc(PATH_MAX); 6055 if (realpath(res, res1) != NULL) { 6056 if (res != argv0) 6057 free(__DECONST(char *, res)); 6058 res = res1; 6059 } else { 6060 free(res1); 6061 } 6062 } 6063 *binpath_res = res; 6064 return (fd); 6065 } 6066 6067 /* 6068 * Parse a set of command-line arguments. 6069 */ 6070 static int 6071 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp, 6072 const char **argv0, bool *dir_ignore) 6073 { 6074 const char *arg; 6075 char machine[64]; 6076 size_t sz; 6077 int arglen, fd, i, j, mib[2]; 6078 char opt; 6079 bool seen_b, seen_f; 6080 6081 dbg("Parsing command-line arguments"); 6082 *use_pathp = false; 6083 *fdp = -1; 6084 *dir_ignore = false; 6085 seen_b = seen_f = false; 6086 6087 for (i = 1; i < argc; i++ ) { 6088 arg = argv[i]; 6089 dbg("argv[%d]: '%s'", i, arg); 6090 6091 /* 6092 * rtld arguments end with an explicit "--" or with the first 6093 * non-prefixed argument. 6094 */ 6095 if (strcmp(arg, "--") == 0) { 6096 i++; 6097 break; 6098 } 6099 if (arg[0] != '-') 6100 break; 6101 6102 /* 6103 * All other arguments are single-character options that can 6104 * be combined, so we need to search through `arg` for them. 6105 */ 6106 arglen = strlen(arg); 6107 for (j = 1; j < arglen; j++) { 6108 opt = arg[j]; 6109 if (opt == 'h') { 6110 print_usage(argv[0]); 6111 _exit(0); 6112 } else if (opt == 'b') { 6113 if (seen_f) { 6114 _rtld_error("Both -b and -f specified"); 6115 rtld_die(); 6116 } 6117 if (j != arglen - 1) { 6118 _rtld_error("Invalid options: %s", arg); 6119 rtld_die(); 6120 } 6121 i++; 6122 *argv0 = argv[i]; 6123 seen_b = true; 6124 break; 6125 } else if (opt == 'd') { 6126 *dir_ignore = true; 6127 } else if (opt == 'f') { 6128 if (seen_b) { 6129 _rtld_error("Both -b and -f specified"); 6130 rtld_die(); 6131 } 6132 6133 /* 6134 * -f XX can be used to specify a 6135 * descriptor for the binary named at 6136 * the command line (i.e., the later 6137 * argument will specify the process 6138 * name but the descriptor is what 6139 * will actually be executed). 6140 * 6141 * -f must be the last option in the 6142 * group, e.g., -abcf <fd>. 6143 */ 6144 if (j != arglen - 1) { 6145 _rtld_error("Invalid options: %s", arg); 6146 rtld_die(); 6147 } 6148 i++; 6149 fd = parse_integer(argv[i]); 6150 if (fd == -1) { 6151 _rtld_error( 6152 "Invalid file descriptor: '%s'", 6153 argv[i]); 6154 rtld_die(); 6155 } 6156 *fdp = fd; 6157 seen_f = true; 6158 break; 6159 } else if (opt == 'p') { 6160 *use_pathp = true; 6161 } else if (opt == 'u') { 6162 trust = false; 6163 } else if (opt == 'v') { 6164 machine[0] = '\0'; 6165 mib[0] = CTL_HW; 6166 mib[1] = HW_MACHINE; 6167 sz = sizeof(machine); 6168 sysctl(mib, nitems(mib), machine, &sz, NULL, 0); 6169 ld_elf_hints_path = ld_get_env_var( 6170 LD_ELF_HINTS_PATH); 6171 set_ld_elf_hints_path(); 6172 rtld_printf( 6173 "FreeBSD ld-elf.so.1 %s\n" 6174 "FreeBSD_version %d\n" 6175 "Default lib path %s\n" 6176 "Hints lib path %s\n" 6177 "Env prefix %s\n" 6178 "Default hint file %s\n" 6179 "Hint file %s\n" 6180 "libmap file %s\n" 6181 "Optional static TLS size %zd bytes\n", 6182 machine, 6183 __FreeBSD_version, ld_standard_library_path, 6184 gethints(false), 6185 ld_env_prefix, ld_elf_hints_default, 6186 ld_elf_hints_path, 6187 ld_path_libmap_conf, 6188 ld_static_tls_extra); 6189 _exit(0); 6190 } else { 6191 _rtld_error("Invalid argument: '%s'", arg); 6192 print_usage(argv[0]); 6193 rtld_die(); 6194 } 6195 } 6196 } 6197 6198 if (!seen_b) 6199 *argv0 = argv[i]; 6200 return (i); 6201 } 6202 6203 /* 6204 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 6205 */ 6206 static int 6207 parse_integer(const char *str) 6208 { 6209 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 6210 const char *orig; 6211 int n; 6212 char c; 6213 6214 orig = str; 6215 n = 0; 6216 for (c = *str; c != '\0'; c = *++str) { 6217 if (c < '0' || c > '9') 6218 return (-1); 6219 6220 n *= RADIX; 6221 n += c - '0'; 6222 } 6223 6224 /* Make sure we actually parsed something. */ 6225 if (str == orig) 6226 return (-1); 6227 return (n); 6228 } 6229 6230 static void 6231 print_usage(const char *argv0) 6232 { 6233 6234 rtld_printf( 6235 "Usage: %s [-h] [-b <exe>] [-d] [-f <FD>] [-p] [--] <binary> [<args>]\n" 6236 "\n" 6237 "Options:\n" 6238 " -h Display this help message\n" 6239 " -b <exe> Execute <exe> instead of <binary>, arg0 is <binary>\n" 6240 " -d Ignore lack of exec permissions for the binary\n" 6241 " -f <FD> Execute <FD> instead of searching for <binary>\n" 6242 " -p Search in PATH for named binary\n" 6243 " -u Ignore LD_ environment variables\n" 6244 " -v Display identification information\n" 6245 " -- End of RTLD options\n" 6246 " <binary> Name of process to execute\n" 6247 " <args> Arguments to the executed process\n", argv0); 6248 } 6249 6250 #define AUXFMT(at, xfmt) [at] = { .name = #at, .fmt = xfmt } 6251 static const struct auxfmt { 6252 const char *name; 6253 const char *fmt; 6254 } auxfmts[] = { 6255 AUXFMT(AT_NULL, NULL), 6256 AUXFMT(AT_IGNORE, NULL), 6257 AUXFMT(AT_EXECFD, "%ld"), 6258 AUXFMT(AT_PHDR, "%p"), 6259 AUXFMT(AT_PHENT, "%lu"), 6260 AUXFMT(AT_PHNUM, "%lu"), 6261 AUXFMT(AT_PAGESZ, "%lu"), 6262 AUXFMT(AT_BASE, "%#lx"), 6263 AUXFMT(AT_FLAGS, "%#lx"), 6264 AUXFMT(AT_ENTRY, "%p"), 6265 AUXFMT(AT_NOTELF, NULL), 6266 AUXFMT(AT_UID, "%ld"), 6267 AUXFMT(AT_EUID, "%ld"), 6268 AUXFMT(AT_GID, "%ld"), 6269 AUXFMT(AT_EGID, "%ld"), 6270 AUXFMT(AT_EXECPATH, "%s"), 6271 AUXFMT(AT_CANARY, "%p"), 6272 AUXFMT(AT_CANARYLEN, "%lu"), 6273 AUXFMT(AT_OSRELDATE, "%lu"), 6274 AUXFMT(AT_NCPUS, "%lu"), 6275 AUXFMT(AT_PAGESIZES, "%p"), 6276 AUXFMT(AT_PAGESIZESLEN, "%lu"), 6277 AUXFMT(AT_TIMEKEEP, "%p"), 6278 AUXFMT(AT_STACKPROT, "%#lx"), 6279 AUXFMT(AT_EHDRFLAGS, "%#lx"), 6280 AUXFMT(AT_HWCAP, "%#lx"), 6281 AUXFMT(AT_HWCAP2, "%#lx"), 6282 AUXFMT(AT_BSDFLAGS, "%#lx"), 6283 AUXFMT(AT_ARGC, "%lu"), 6284 AUXFMT(AT_ARGV, "%p"), 6285 AUXFMT(AT_ENVC, "%p"), 6286 AUXFMT(AT_ENVV, "%p"), 6287 AUXFMT(AT_PS_STRINGS, "%p"), 6288 AUXFMT(AT_FXRNG, "%p"), 6289 AUXFMT(AT_KPRELOAD, "%p"), 6290 AUXFMT(AT_USRSTACKBASE, "%#lx"), 6291 AUXFMT(AT_USRSTACKLIM, "%#lx"), 6292 }; 6293 6294 static bool 6295 is_ptr_fmt(const char *fmt) 6296 { 6297 char last; 6298 6299 last = fmt[strlen(fmt) - 1]; 6300 return (last == 'p' || last == 's'); 6301 } 6302 6303 static void 6304 dump_auxv(Elf_Auxinfo **aux_info) 6305 { 6306 Elf_Auxinfo *auxp; 6307 const struct auxfmt *fmt; 6308 int i; 6309 6310 for (i = 0; i < AT_COUNT; i++) { 6311 auxp = aux_info[i]; 6312 if (auxp == NULL) 6313 continue; 6314 fmt = &auxfmts[i]; 6315 if (fmt->fmt == NULL) 6316 continue; 6317 rtld_fdprintf(STDOUT_FILENO, "%s:\t", fmt->name); 6318 if (is_ptr_fmt(fmt->fmt)) { 6319 rtld_fdprintfx(STDOUT_FILENO, fmt->fmt, 6320 auxp->a_un.a_ptr); 6321 } else { 6322 rtld_fdprintfx(STDOUT_FILENO, fmt->fmt, 6323 auxp->a_un.a_val); 6324 } 6325 rtld_fdprintf(STDOUT_FILENO, "\n"); 6326 } 6327 } 6328 6329 /* 6330 * Overrides for libc_pic-provided functions. 6331 */ 6332 6333 int 6334 __getosreldate(void) 6335 { 6336 size_t len; 6337 int oid[2]; 6338 int error, osrel; 6339 6340 if (osreldate != 0) 6341 return (osreldate); 6342 6343 oid[0] = CTL_KERN; 6344 oid[1] = KERN_OSRELDATE; 6345 osrel = 0; 6346 len = sizeof(osrel); 6347 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 6348 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 6349 osreldate = osrel; 6350 return (osreldate); 6351 } 6352 const char * 6353 rtld_strerror(int errnum) 6354 { 6355 6356 if (errnum < 0 || errnum >= sys_nerr) 6357 return ("Unknown error"); 6358 return (sys_errlist[errnum]); 6359 } 6360 6361 char * 6362 getenv(const char *name) 6363 { 6364 return (__DECONST(char *, rtld_get_env_val(environ, name, 6365 strlen(name)))); 6366 } 6367 6368 /* malloc */ 6369 void * 6370 malloc(size_t nbytes) 6371 { 6372 6373 return (__crt_malloc(nbytes)); 6374 } 6375 6376 void * 6377 calloc(size_t num, size_t size) 6378 { 6379 6380 return (__crt_calloc(num, size)); 6381 } 6382 6383 void 6384 free(void *cp) 6385 { 6386 6387 __crt_free(cp); 6388 } 6389 6390 void * 6391 realloc(void *cp, size_t nbytes) 6392 { 6393 6394 return (__crt_realloc(cp, nbytes)); 6395 } 6396 6397 extern int _rtld_version__FreeBSD_version __exported; 6398 int _rtld_version__FreeBSD_version = __FreeBSD_version; 6399 6400 extern char _rtld_version_laddr_offset __exported; 6401 char _rtld_version_laddr_offset; 6402 6403 extern char _rtld_version_dlpi_tls_data __exported; 6404 char _rtld_version_dlpi_tls_data; 6405