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 (arch_digest_note(obj, note)) 1733 continue; 1734 1735 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1736 note->n_descsz != sizeof(int32_t)) 1737 continue; 1738 if (note->n_type != NT_FREEBSD_ABI_TAG && 1739 note->n_type != NT_FREEBSD_FEATURE_CTL && 1740 note->n_type != NT_FREEBSD_NOINIT_TAG) 1741 continue; 1742 note_name = (const char *)(note + 1); 1743 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1744 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1745 continue; 1746 switch (note->n_type) { 1747 case NT_FREEBSD_ABI_TAG: 1748 /* FreeBSD osrel note */ 1749 p = (uintptr_t)(note + 1); 1750 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1751 obj->osrel = *(const int32_t *)(p); 1752 dbg("note osrel %d", obj->osrel); 1753 break; 1754 case NT_FREEBSD_FEATURE_CTL: 1755 /* FreeBSD ABI feature control note */ 1756 p = (uintptr_t)(note + 1); 1757 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1758 obj->fctl0 = *(const uint32_t *)(p); 1759 dbg("note fctl0 %#x", obj->fctl0); 1760 break; 1761 case NT_FREEBSD_NOINIT_TAG: 1762 /* FreeBSD 'crt does not call init' note */ 1763 obj->crt_no_init = true; 1764 dbg("note crt_no_init"); 1765 break; 1766 } 1767 } 1768 } 1769 1770 static Obj_Entry * 1771 dlcheck(void *handle) 1772 { 1773 Obj_Entry *obj; 1774 1775 TAILQ_FOREACH(obj, &obj_list, next) { 1776 if (obj == (Obj_Entry *) handle) 1777 break; 1778 } 1779 1780 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1781 _rtld_error("Invalid shared object handle %p", handle); 1782 return (NULL); 1783 } 1784 return (obj); 1785 } 1786 1787 /* 1788 * If the given object is already in the donelist, return true. Otherwise 1789 * add the object to the list and return false. 1790 */ 1791 static bool 1792 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1793 { 1794 unsigned int i; 1795 1796 for (i = 0; i < dlp->num_used; i++) 1797 if (dlp->objs[i] == obj) 1798 return (true); 1799 /* 1800 * Our donelist allocation should always be sufficient. But if 1801 * our threads locking isn't working properly, more shared objects 1802 * could have been loaded since we allocated the list. That should 1803 * never happen, but we'll handle it properly just in case it does. 1804 */ 1805 if (dlp->num_used < dlp->num_alloc) 1806 dlp->objs[dlp->num_used++] = obj; 1807 return (false); 1808 } 1809 1810 /* 1811 * SysV hash function for symbol table lookup. It is a slightly optimized 1812 * version of the hash specified by the System V ABI. 1813 */ 1814 Elf32_Word 1815 elf_hash(const char *name) 1816 { 1817 const unsigned char *p = (const unsigned char *)name; 1818 Elf32_Word h = 0; 1819 1820 while (*p != '\0') { 1821 h = (h << 4) + *p++; 1822 h ^= (h >> 24) & 0xf0; 1823 } 1824 return (h & 0x0fffffff); 1825 } 1826 1827 /* 1828 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1829 * unsigned in case it's implemented with a wider type. 1830 */ 1831 static uint32_t 1832 gnu_hash(const char *s) 1833 { 1834 uint32_t h; 1835 unsigned char c; 1836 1837 h = 5381; 1838 for (c = *s; c != '\0'; c = *++s) 1839 h = h * 33 + c; 1840 return (h & 0xffffffff); 1841 } 1842 1843 1844 /* 1845 * Find the library with the given name, and return its full pathname. 1846 * The returned string is dynamically allocated. Generates an error 1847 * message and returns NULL if the library cannot be found. 1848 * 1849 * If the second argument is non-NULL, then it refers to an already- 1850 * loaded shared object, whose library search path will be searched. 1851 * 1852 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1853 * descriptor (which is close-on-exec) will be passed out via the third 1854 * argument. 1855 * 1856 * The search order is: 1857 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1858 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1859 * LD_LIBRARY_PATH 1860 * DT_RUNPATH in the referencing file 1861 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1862 * from list) 1863 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1864 * 1865 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1866 */ 1867 static char * 1868 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1869 { 1870 char *pathname, *refobj_path; 1871 const char *name; 1872 bool nodeflib, objgiven; 1873 1874 objgiven = refobj != NULL; 1875 1876 if (libmap_disable || !objgiven || 1877 (name = lm_find(refobj->path, xname)) == NULL) 1878 name = xname; 1879 1880 if (strchr(name, '/') != NULL) { /* Hard coded pathname */ 1881 if (name[0] != '/' && !trust) { 1882 _rtld_error("Absolute pathname required " 1883 "for shared object \"%s\"", name); 1884 return (NULL); 1885 } 1886 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1887 __DECONST(char *, name))); 1888 } 1889 1890 dbg(" Searching for \"%s\"", name); 1891 refobj_path = objgiven ? refobj->path : NULL; 1892 1893 /* 1894 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1895 * back to pre-conforming behaviour if user requested so with 1896 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1897 * nodeflib. 1898 */ 1899 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1900 pathname = search_library_path(name, ld_library_path, 1901 refobj_path, fdp); 1902 if (pathname != NULL) 1903 return (pathname); 1904 if (refobj != NULL) { 1905 pathname = search_library_path(name, refobj->rpath, 1906 refobj_path, fdp); 1907 if (pathname != NULL) 1908 return (pathname); 1909 } 1910 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1911 if (pathname != NULL) 1912 return (pathname); 1913 pathname = search_library_path(name, gethints(false), 1914 refobj_path, fdp); 1915 if (pathname != NULL) 1916 return (pathname); 1917 pathname = search_library_path(name, ld_standard_library_path, 1918 refobj_path, fdp); 1919 if (pathname != NULL) 1920 return (pathname); 1921 } else { 1922 nodeflib = objgiven ? refobj->z_nodeflib : false; 1923 if (objgiven) { 1924 pathname = search_library_path(name, refobj->rpath, 1925 refobj->path, fdp); 1926 if (pathname != NULL) 1927 return (pathname); 1928 } 1929 if (objgiven && refobj->runpath == NULL && refobj != obj_main) { 1930 pathname = search_library_path(name, obj_main->rpath, 1931 refobj_path, fdp); 1932 if (pathname != NULL) 1933 return (pathname); 1934 } 1935 pathname = search_library_path(name, ld_library_path, 1936 refobj_path, fdp); 1937 if (pathname != NULL) 1938 return (pathname); 1939 if (objgiven) { 1940 pathname = search_library_path(name, refobj->runpath, 1941 refobj_path, fdp); 1942 if (pathname != NULL) 1943 return (pathname); 1944 } 1945 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1946 if (pathname != NULL) 1947 return (pathname); 1948 pathname = search_library_path(name, gethints(nodeflib), 1949 refobj_path, fdp); 1950 if (pathname != NULL) 1951 return (pathname); 1952 if (objgiven && !nodeflib) { 1953 pathname = search_library_path(name, 1954 ld_standard_library_path, refobj_path, fdp); 1955 if (pathname != NULL) 1956 return (pathname); 1957 } 1958 } 1959 1960 if (objgiven && refobj->path != NULL) { 1961 _rtld_error("Shared object \"%s\" not found, " 1962 "required by \"%s\"", name, basename(refobj->path)); 1963 } else { 1964 _rtld_error("Shared object \"%s\" not found", name); 1965 } 1966 return (NULL); 1967 } 1968 1969 /* 1970 * Given a symbol number in a referencing object, find the corresponding 1971 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1972 * no definition was found. Returns a pointer to the Obj_Entry of the 1973 * defining object via the reference parameter DEFOBJ_OUT. 1974 */ 1975 const Elf_Sym * 1976 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1977 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1978 RtldLockState *lockstate) 1979 { 1980 const Elf_Sym *ref; 1981 const Elf_Sym *def; 1982 const Obj_Entry *defobj; 1983 const Ver_Entry *ve; 1984 SymLook req; 1985 const char *name; 1986 int res; 1987 1988 /* 1989 * If we have already found this symbol, get the information from 1990 * the cache. 1991 */ 1992 if (symnum >= refobj->dynsymcount) 1993 return (NULL); /* Bad object */ 1994 if (cache != NULL && cache[symnum].sym != NULL) { 1995 *defobj_out = cache[symnum].obj; 1996 return (cache[symnum].sym); 1997 } 1998 1999 ref = refobj->symtab + symnum; 2000 name = refobj->strtab + ref->st_name; 2001 def = NULL; 2002 defobj = NULL; 2003 ve = NULL; 2004 2005 /* 2006 * We don't have to do a full scale lookup if the symbol is local. 2007 * We know it will bind to the instance in this load module; to 2008 * which we already have a pointer (ie ref). By not doing a lookup, 2009 * we not only improve performance, but it also avoids unresolvable 2010 * symbols when local symbols are not in the hash table. This has 2011 * been seen with the ia64 toolchain. 2012 */ 2013 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 2014 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 2015 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 2016 symnum); 2017 } 2018 symlook_init(&req, name); 2019 req.flags = flags; 2020 ve = req.ventry = fetch_ventry(refobj, symnum); 2021 req.lockstate = lockstate; 2022 res = symlook_default(&req, refobj); 2023 if (res == 0) { 2024 def = req.sym_out; 2025 defobj = req.defobj_out; 2026 } 2027 } else { 2028 def = ref; 2029 defobj = refobj; 2030 } 2031 2032 /* 2033 * If we found no definition and the reference is weak, treat the 2034 * symbol as having the value zero. 2035 */ 2036 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 2037 def = &sym_zero; 2038 defobj = obj_main; 2039 } 2040 2041 if (def != NULL) { 2042 *defobj_out = defobj; 2043 /* Record the information in the cache to avoid subsequent lookups. */ 2044 if (cache != NULL) { 2045 cache[symnum].sym = def; 2046 cache[symnum].obj = defobj; 2047 } 2048 } else { 2049 if (refobj != &obj_rtld) 2050 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name, 2051 ve != NULL ? "@" : "", ve != NULL ? ve->name : ""); 2052 } 2053 return (def); 2054 } 2055 2056 /* Convert between native byte order and forced little resp. big endian. */ 2057 #define COND_SWAP(n) (is_le ? le32toh(n) : be32toh(n)) 2058 2059 /* 2060 * Return the search path from the ldconfig hints file, reading it if 2061 * necessary. If nostdlib is true, then the default search paths are 2062 * not added to result. 2063 * 2064 * Returns NULL if there are problems with the hints file, 2065 * or if the search path there is empty. 2066 */ 2067 static const char * 2068 gethints(bool nostdlib) 2069 { 2070 static char *filtered_path; 2071 static const char *hints; 2072 static struct elfhints_hdr hdr; 2073 struct fill_search_info_args sargs, hargs; 2074 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 2075 struct dl_serpath *SLPpath, *hintpath; 2076 char *p; 2077 struct stat hint_stat; 2078 unsigned int SLPndx, hintndx, fndx, fcount; 2079 int fd; 2080 size_t flen; 2081 uint32_t dl; 2082 uint32_t magic; /* Magic number */ 2083 uint32_t version; /* File version (1) */ 2084 uint32_t strtab; /* Offset of string table in file */ 2085 uint32_t dirlist; /* Offset of directory list in string table */ 2086 uint32_t dirlistlen; /* strlen(dirlist) */ 2087 bool is_le; /* Does the hints file use little endian */ 2088 bool skip; 2089 2090 /* First call, read the hints file */ 2091 if (hints == NULL) { 2092 /* Keep from trying again in case the hints file is bad. */ 2093 hints = ""; 2094 2095 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) { 2096 dbg("failed to open hints file \"%s\"", ld_elf_hints_path); 2097 return (NULL); 2098 } 2099 2100 /* 2101 * Check of hdr.dirlistlen value against type limit 2102 * intends to pacify static analyzers. Further 2103 * paranoia leads to checks that dirlist is fully 2104 * contained in the file range. 2105 */ 2106 if (read(fd, &hdr, sizeof hdr) != sizeof hdr) { 2107 dbg("failed to read %lu bytes from hints file \"%s\"", 2108 (u_long)sizeof hdr, ld_elf_hints_path); 2109 cleanup1: 2110 close(fd); 2111 hdr.dirlistlen = 0; 2112 return (NULL); 2113 } 2114 dbg("host byte-order: %s-endian", le32toh(1) == 1 ? "little" : "big"); 2115 dbg("hints file byte-order: %s-endian", 2116 hdr.magic == htole32(ELFHINTS_MAGIC) ? "little" : "big"); 2117 is_le = /*htole32(1) == 1 || */ hdr.magic == htole32(ELFHINTS_MAGIC); 2118 magic = COND_SWAP(hdr.magic); 2119 version = COND_SWAP(hdr.version); 2120 strtab = COND_SWAP(hdr.strtab); 2121 dirlist = COND_SWAP(hdr.dirlist); 2122 dirlistlen = COND_SWAP(hdr.dirlistlen); 2123 if (magic != ELFHINTS_MAGIC) { 2124 dbg("invalid magic number %#08x (expected: %#08x)", 2125 magic, ELFHINTS_MAGIC); 2126 goto cleanup1; 2127 } 2128 if (version != 1) { 2129 dbg("hints file version %d (expected: 1)", version); 2130 goto cleanup1; 2131 } 2132 if (dirlistlen > UINT_MAX / 2) { 2133 dbg("directory list is to long: %d > %d", 2134 dirlistlen, UINT_MAX / 2); 2135 goto cleanup1; 2136 } 2137 if (fstat(fd, &hint_stat) == -1) { 2138 dbg("failed to find length of hints file \"%s\"", 2139 ld_elf_hints_path); 2140 goto cleanup1; 2141 } 2142 dl = strtab; 2143 if (dl + dirlist < dl) { 2144 dbg("invalid string table position %d", dl); 2145 goto cleanup1; 2146 } 2147 dl += dirlist; 2148 if (dl + dirlistlen < dl) { 2149 dbg("invalid directory list offset %d", dirlist); 2150 goto cleanup1; 2151 } 2152 dl += dirlistlen; 2153 if (dl > hint_stat.st_size) { 2154 dbg("hints file \"%s\" is truncated (%d vs. %jd bytes)", 2155 ld_elf_hints_path, dl, (uintmax_t)hint_stat.st_size); 2156 goto cleanup1; 2157 } 2158 p = xmalloc(dirlistlen + 1); 2159 if (pread(fd, p, dirlistlen + 1, 2160 strtab + dirlist) != (ssize_t)dirlistlen + 1 || 2161 p[dirlistlen] != '\0') { 2162 free(p); 2163 dbg("failed to read %d bytes starting at %d from hints file \"%s\"", 2164 dirlistlen + 1, strtab + dirlist, ld_elf_hints_path); 2165 goto cleanup1; 2166 } 2167 hints = p; 2168 close(fd); 2169 } 2170 2171 /* 2172 * If caller agreed to receive list which includes the default 2173 * paths, we are done. Otherwise, if we still did not 2174 * calculated filtered result, do it now. 2175 */ 2176 if (!nostdlib) 2177 return (hints[0] != '\0' ? hints : NULL); 2178 if (filtered_path != NULL) 2179 goto filt_ret; 2180 2181 /* 2182 * Obtain the list of all configured search paths, and the 2183 * list of the default paths. 2184 * 2185 * First estimate the size of the results. 2186 */ 2187 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2188 smeta.dls_cnt = 0; 2189 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2190 hmeta.dls_cnt = 0; 2191 2192 sargs.request = RTLD_DI_SERINFOSIZE; 2193 sargs.serinfo = &smeta; 2194 hargs.request = RTLD_DI_SERINFOSIZE; 2195 hargs.serinfo = &hmeta; 2196 2197 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 2198 &sargs); 2199 path_enumerate(hints, fill_search_info, NULL, &hargs); 2200 2201 SLPinfo = xmalloc(smeta.dls_size); 2202 hintinfo = xmalloc(hmeta.dls_size); 2203 2204 /* 2205 * Next fetch both sets of paths. 2206 */ 2207 sargs.request = RTLD_DI_SERINFO; 2208 sargs.serinfo = SLPinfo; 2209 sargs.serpath = &SLPinfo->dls_serpath[0]; 2210 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 2211 2212 hargs.request = RTLD_DI_SERINFO; 2213 hargs.serinfo = hintinfo; 2214 hargs.serpath = &hintinfo->dls_serpath[0]; 2215 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 2216 2217 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 2218 &sargs); 2219 path_enumerate(hints, fill_search_info, NULL, &hargs); 2220 2221 /* 2222 * Now calculate the difference between two sets, by excluding 2223 * standard paths from the full set. 2224 */ 2225 fndx = 0; 2226 fcount = 0; 2227 filtered_path = xmalloc(dirlistlen + 1); 2228 hintpath = &hintinfo->dls_serpath[0]; 2229 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 2230 skip = false; 2231 SLPpath = &SLPinfo->dls_serpath[0]; 2232 /* 2233 * Check each standard path against current. 2234 */ 2235 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 2236 /* matched, skip the path */ 2237 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 2238 skip = true; 2239 break; 2240 } 2241 } 2242 if (skip) 2243 continue; 2244 /* 2245 * Not matched against any standard path, add the path 2246 * to result. Separate consequtive paths with ':'. 2247 */ 2248 if (fcount > 0) { 2249 filtered_path[fndx] = ':'; 2250 fndx++; 2251 } 2252 fcount++; 2253 flen = strlen(hintpath->dls_name); 2254 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 2255 fndx += flen; 2256 } 2257 filtered_path[fndx] = '\0'; 2258 2259 free(SLPinfo); 2260 free(hintinfo); 2261 2262 filt_ret: 2263 return (filtered_path[0] != '\0' ? filtered_path : NULL); 2264 } 2265 2266 static void 2267 init_dag(Obj_Entry *root) 2268 { 2269 const Needed_Entry *needed; 2270 const Objlist_Entry *elm; 2271 DoneList donelist; 2272 2273 if (root->dag_inited) 2274 return; 2275 donelist_init(&donelist); 2276 2277 /* Root object belongs to own DAG. */ 2278 objlist_push_tail(&root->dldags, root); 2279 objlist_push_tail(&root->dagmembers, root); 2280 donelist_check(&donelist, root); 2281 2282 /* 2283 * Add dependencies of root object to DAG in breadth order 2284 * by exploiting the fact that each new object get added 2285 * to the tail of the dagmembers list. 2286 */ 2287 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2288 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 2289 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 2290 continue; 2291 objlist_push_tail(&needed->obj->dldags, root); 2292 objlist_push_tail(&root->dagmembers, needed->obj); 2293 } 2294 } 2295 root->dag_inited = true; 2296 } 2297 2298 static void 2299 init_marker(Obj_Entry *marker) 2300 { 2301 2302 bzero(marker, sizeof(*marker)); 2303 marker->marker = true; 2304 } 2305 2306 Obj_Entry * 2307 globallist_curr(const Obj_Entry *obj) 2308 { 2309 2310 for (;;) { 2311 if (obj == NULL) 2312 return (NULL); 2313 if (!obj->marker) 2314 return (__DECONST(Obj_Entry *, obj)); 2315 obj = TAILQ_PREV(obj, obj_entry_q, next); 2316 } 2317 } 2318 2319 Obj_Entry * 2320 globallist_next(const Obj_Entry *obj) 2321 { 2322 2323 for (;;) { 2324 obj = TAILQ_NEXT(obj, next); 2325 if (obj == NULL) 2326 return (NULL); 2327 if (!obj->marker) 2328 return (__DECONST(Obj_Entry *, obj)); 2329 } 2330 } 2331 2332 /* Prevent the object from being unmapped while the bind lock is dropped. */ 2333 static void 2334 hold_object(Obj_Entry *obj) 2335 { 2336 2337 obj->holdcount++; 2338 } 2339 2340 static void 2341 unhold_object(Obj_Entry *obj) 2342 { 2343 2344 assert(obj->holdcount > 0); 2345 if (--obj->holdcount == 0 && obj->unholdfree) 2346 release_object(obj); 2347 } 2348 2349 static void 2350 process_z(Obj_Entry *root) 2351 { 2352 const Objlist_Entry *elm; 2353 Obj_Entry *obj; 2354 2355 /* 2356 * Walk over object DAG and process every dependent object 2357 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 2358 * to grow their own DAG. 2359 * 2360 * For DF_1_GLOBAL, DAG is required for symbol lookups in 2361 * symlook_global() to work. 2362 * 2363 * For DF_1_NODELETE, the DAG should have its reference upped. 2364 */ 2365 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2366 obj = elm->obj; 2367 if (obj == NULL) 2368 continue; 2369 if (obj->z_nodelete && !obj->ref_nodel) { 2370 dbg("obj %s -z nodelete", obj->path); 2371 init_dag(obj); 2372 ref_dag(obj); 2373 obj->ref_nodel = true; 2374 } 2375 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 2376 dbg("obj %s -z global", obj->path); 2377 objlist_push_tail(&list_global, obj); 2378 init_dag(obj); 2379 } 2380 } 2381 } 2382 2383 static void 2384 parse_rtld_phdr(Obj_Entry *obj) 2385 { 2386 const Elf_Phdr *ph; 2387 Elf_Addr note_start, note_end; 2388 2389 obj->stack_flags = PF_X | PF_R | PF_W; 2390 for (ph = obj->phdr; (const char *)ph < (const char *)obj->phdr + 2391 obj->phsize; ph++) { 2392 switch (ph->p_type) { 2393 case PT_GNU_STACK: 2394 obj->stack_flags = ph->p_flags; 2395 break; 2396 case PT_GNU_RELRO: 2397 obj->relro_page = obj->relocbase + 2398 rtld_trunc_page(ph->p_vaddr); 2399 obj->relro_size = rtld_round_page(ph->p_memsz); 2400 break; 2401 case PT_NOTE: 2402 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 2403 note_end = note_start + ph->p_filesz; 2404 digest_notes(obj, note_start, note_end); 2405 break; 2406 } 2407 } 2408 } 2409 2410 /* 2411 * Initialize the dynamic linker. The argument is the address at which 2412 * the dynamic linker has been mapped into memory. The primary task of 2413 * this function is to relocate the dynamic linker. 2414 */ 2415 static void 2416 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 2417 { 2418 Obj_Entry objtmp; /* Temporary rtld object */ 2419 const Elf_Ehdr *ehdr; 2420 const Elf_Dyn *dyn_rpath; 2421 const Elf_Dyn *dyn_soname; 2422 const Elf_Dyn *dyn_runpath; 2423 2424 #ifdef RTLD_INIT_PAGESIZES_EARLY 2425 /* The page size is required by the dynamic memory allocator. */ 2426 init_pagesizes(aux_info); 2427 #endif 2428 2429 /* 2430 * Conjure up an Obj_Entry structure for the dynamic linker. 2431 * 2432 * The "path" member can't be initialized yet because string constants 2433 * cannot yet be accessed. Below we will set it correctly. 2434 */ 2435 memset(&objtmp, 0, sizeof(objtmp)); 2436 objtmp.path = NULL; 2437 objtmp.rtld = true; 2438 objtmp.mapbase = mapbase; 2439 #ifdef PIC 2440 objtmp.relocbase = mapbase; 2441 #endif 2442 2443 objtmp.dynamic = rtld_dynamic(&objtmp); 2444 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 2445 assert(objtmp.needed == NULL); 2446 assert(!objtmp.textrel); 2447 /* 2448 * Temporarily put the dynamic linker entry into the object list, so 2449 * that symbols can be found. 2450 */ 2451 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 2452 2453 ehdr = (Elf_Ehdr *)mapbase; 2454 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 2455 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 2456 2457 /* Initialize the object list. */ 2458 TAILQ_INIT(&obj_list); 2459 2460 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 2461 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 2462 2463 #ifndef RTLD_INIT_PAGESIZES_EARLY 2464 /* The page size is required by the dynamic memory allocator. */ 2465 init_pagesizes(aux_info); 2466 #endif 2467 2468 if (aux_info[AT_OSRELDATE] != NULL) 2469 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 2470 2471 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 2472 2473 /* Replace the path with a dynamically allocated copy. */ 2474 obj_rtld.path = xstrdup(ld_path_rtld); 2475 2476 parse_rtld_phdr(&obj_rtld); 2477 if (obj_enforce_relro(&obj_rtld) == -1) 2478 rtld_die(); 2479 2480 r_debug.r_version = R_DEBUG_VERSION; 2481 r_debug.r_brk = r_debug_state; 2482 r_debug.r_state = RT_CONSISTENT; 2483 r_debug.r_ldbase = obj_rtld.relocbase; 2484 } 2485 2486 /* 2487 * Retrieve the array of supported page sizes. The kernel provides the page 2488 * sizes in increasing order. 2489 */ 2490 static void 2491 init_pagesizes(Elf_Auxinfo **aux_info) 2492 { 2493 static size_t psa[MAXPAGESIZES]; 2494 int mib[2]; 2495 size_t len, size; 2496 2497 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 2498 NULL) { 2499 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 2500 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 2501 } else { 2502 len = 2; 2503 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 2504 size = sizeof(psa); 2505 else { 2506 /* As a fallback, retrieve the base page size. */ 2507 size = sizeof(psa[0]); 2508 if (aux_info[AT_PAGESZ] != NULL) { 2509 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 2510 goto psa_filled; 2511 } else { 2512 mib[0] = CTL_HW; 2513 mib[1] = HW_PAGESIZE; 2514 len = 2; 2515 } 2516 } 2517 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 2518 _rtld_error("sysctl for hw.pagesize(s) failed"); 2519 rtld_die(); 2520 } 2521 psa_filled: 2522 pagesizes = psa; 2523 } 2524 npagesizes = size / sizeof(pagesizes[0]); 2525 /* Discard any invalid entries at the end of the array. */ 2526 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 2527 npagesizes--; 2528 2529 page_size = pagesizes[0]; 2530 } 2531 2532 /* 2533 * Add the init functions from a needed object list (and its recursive 2534 * needed objects) to "list". This is not used directly; it is a helper 2535 * function for initlist_add_objects(). The write lock must be held 2536 * when this function is called. 2537 */ 2538 static void 2539 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 2540 { 2541 /* Recursively process the successor needed objects. */ 2542 if (needed->next != NULL) 2543 initlist_add_neededs(needed->next, list); 2544 2545 /* Process the current needed object. */ 2546 if (needed->obj != NULL) 2547 initlist_add_objects(needed->obj, needed->obj, list); 2548 } 2549 2550 /* 2551 * Scan all of the DAGs rooted in the range of objects from "obj" to 2552 * "tail" and add their init functions to "list". This recurses over 2553 * the DAGs and ensure the proper init ordering such that each object's 2554 * needed libraries are initialized before the object itself. At the 2555 * same time, this function adds the objects to the global finalization 2556 * list "list_fini" in the opposite order. The write lock must be 2557 * held when this function is called. 2558 */ 2559 static void 2560 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2561 { 2562 Obj_Entry *nobj; 2563 2564 if (obj->init_scanned || obj->init_done) 2565 return; 2566 obj->init_scanned = true; 2567 2568 /* Recursively process the successor objects. */ 2569 nobj = globallist_next(obj); 2570 if (nobj != NULL && obj != tail) 2571 initlist_add_objects(nobj, tail, list); 2572 2573 /* Recursively process the needed objects. */ 2574 if (obj->needed != NULL) 2575 initlist_add_neededs(obj->needed, list); 2576 if (obj->needed_filtees != NULL) 2577 initlist_add_neededs(obj->needed_filtees, list); 2578 if (obj->needed_aux_filtees != NULL) 2579 initlist_add_neededs(obj->needed_aux_filtees, list); 2580 2581 /* Add the object to the init list. */ 2582 objlist_push_tail(list, obj); 2583 2584 /* Add the object to the global fini list in the reverse order. */ 2585 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2586 && !obj->on_fini_list) { 2587 objlist_push_head(&list_fini, obj); 2588 obj->on_fini_list = true; 2589 } 2590 } 2591 2592 static void 2593 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate) 2594 { 2595 Needed_Entry *needed, *needed1; 2596 2597 for (needed = n; needed != NULL; needed = needed->next) { 2598 if (needed->obj != NULL) { 2599 dlclose_locked(needed->obj, lockstate); 2600 needed->obj = NULL; 2601 } 2602 } 2603 for (needed = n; needed != NULL; needed = needed1) { 2604 needed1 = needed->next; 2605 free(needed); 2606 } 2607 } 2608 2609 static void 2610 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate) 2611 { 2612 2613 free_needed_filtees(obj->needed_filtees, lockstate); 2614 obj->needed_filtees = NULL; 2615 free_needed_filtees(obj->needed_aux_filtees, lockstate); 2616 obj->needed_aux_filtees = NULL; 2617 obj->filtees_loaded = false; 2618 } 2619 2620 static void 2621 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2622 RtldLockState *lockstate) 2623 { 2624 2625 for (; needed != NULL; needed = needed->next) { 2626 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2627 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2628 RTLD_LOCAL, lockstate); 2629 } 2630 } 2631 2632 static void 2633 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2634 { 2635 if (obj->filtees_loaded || obj->filtees_loading) 2636 return; 2637 lock_restart_for_upgrade(lockstate); 2638 obj->filtees_loading = true; 2639 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2640 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2641 obj->filtees_loaded = true; 2642 obj->filtees_loading = false; 2643 } 2644 2645 static int 2646 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2647 { 2648 Obj_Entry *obj1; 2649 2650 for (; needed != NULL; needed = needed->next) { 2651 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2652 flags & ~RTLD_LO_NOLOAD); 2653 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2654 return (-1); 2655 } 2656 return (0); 2657 } 2658 2659 /* 2660 * Given a shared object, traverse its list of needed objects, and load 2661 * each of them. Returns 0 on success. Generates an error message and 2662 * returns -1 on failure. 2663 */ 2664 static int 2665 load_needed_objects(Obj_Entry *first, int flags) 2666 { 2667 Obj_Entry *obj; 2668 2669 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2670 if (obj->marker) 2671 continue; 2672 if (process_needed(obj, obj->needed, flags) == -1) 2673 return (-1); 2674 } 2675 return (0); 2676 } 2677 2678 static int 2679 load_preload_objects(const char *penv, bool isfd) 2680 { 2681 Obj_Entry *obj; 2682 const char *name; 2683 size_t len; 2684 char savech, *p, *psave; 2685 int fd; 2686 static const char delim[] = " \t:;"; 2687 2688 if (penv == NULL) 2689 return (0); 2690 2691 p = psave = xstrdup(penv); 2692 p += strspn(p, delim); 2693 while (*p != '\0') { 2694 len = strcspn(p, delim); 2695 2696 savech = p[len]; 2697 p[len] = '\0'; 2698 if (isfd) { 2699 name = NULL; 2700 fd = parse_integer(p); 2701 if (fd == -1) { 2702 free(psave); 2703 return (-1); 2704 } 2705 } else { 2706 name = p; 2707 fd = -1; 2708 } 2709 2710 obj = load_object(name, fd, NULL, 0); 2711 if (obj == NULL) { 2712 free(psave); 2713 return (-1); /* XXX - cleanup */ 2714 } 2715 obj->z_interpose = true; 2716 p[len] = savech; 2717 p += len; 2718 p += strspn(p, delim); 2719 } 2720 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2721 2722 free(psave); 2723 return (0); 2724 } 2725 2726 static const char * 2727 printable_path(const char *path) 2728 { 2729 2730 return (path == NULL ? "<unknown>" : path); 2731 } 2732 2733 /* 2734 * Load a shared object into memory, if it is not already loaded. The 2735 * object may be specified by name or by user-supplied file descriptor 2736 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2737 * duplicate is. 2738 * 2739 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2740 * on failure. 2741 */ 2742 static Obj_Entry * 2743 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2744 { 2745 Obj_Entry *obj; 2746 int fd; 2747 struct stat sb; 2748 char *path; 2749 2750 fd = -1; 2751 if (name != NULL) { 2752 TAILQ_FOREACH(obj, &obj_list, next) { 2753 if (obj->marker || obj->doomed) 2754 continue; 2755 if (object_match_name(obj, name)) 2756 return (obj); 2757 } 2758 2759 path = find_library(name, refobj, &fd); 2760 if (path == NULL) 2761 return (NULL); 2762 } else 2763 path = NULL; 2764 2765 if (fd >= 0) { 2766 /* 2767 * search_library_pathfds() opens a fresh file descriptor for the 2768 * library, so there is no need to dup(). 2769 */ 2770 } else if (fd_u == -1) { 2771 /* 2772 * If we didn't find a match by pathname, or the name is not 2773 * supplied, open the file and check again by device and inode. 2774 * This avoids false mismatches caused by multiple links or ".." 2775 * in pathnames. 2776 * 2777 * To avoid a race, we open the file and use fstat() rather than 2778 * using stat(). 2779 */ 2780 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { 2781 _rtld_error("Cannot open \"%s\"", path); 2782 free(path); 2783 return (NULL); 2784 } 2785 } else { 2786 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2787 if (fd == -1) { 2788 _rtld_error("Cannot dup fd"); 2789 free(path); 2790 return (NULL); 2791 } 2792 } 2793 if (fstat(fd, &sb) == -1) { 2794 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2795 close(fd); 2796 free(path); 2797 return (NULL); 2798 } 2799 TAILQ_FOREACH(obj, &obj_list, next) { 2800 if (obj->marker || obj->doomed) 2801 continue; 2802 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2803 break; 2804 } 2805 if (obj != NULL) { 2806 if (name != NULL) 2807 object_add_name(obj, name); 2808 free(path); 2809 close(fd); 2810 return (obj); 2811 } 2812 if (flags & RTLD_LO_NOLOAD) { 2813 free(path); 2814 close(fd); 2815 return (NULL); 2816 } 2817 2818 /* First use of this object, so we must map it in */ 2819 obj = do_load_object(fd, name, path, &sb, flags); 2820 if (obj == NULL) 2821 free(path); 2822 close(fd); 2823 2824 return (obj); 2825 } 2826 2827 static Obj_Entry * 2828 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2829 int flags) 2830 { 2831 Obj_Entry *obj; 2832 struct statfs fs; 2833 2834 /* 2835 * First, make sure that environment variables haven't been 2836 * used to circumvent the noexec flag on a filesystem. 2837 * We ignore fstatfs(2) failures, since fd might reference 2838 * not a file, e.g. shmfd. 2839 */ 2840 if (dangerous_ld_env && fstatfs(fd, &fs) == 0 && 2841 (fs.f_flags & MNT_NOEXEC) != 0) { 2842 _rtld_error("Cannot execute objects on %s", fs.f_mntonname); 2843 return (NULL); 2844 } 2845 2846 dbg("loading \"%s\"", printable_path(path)); 2847 obj = map_object(fd, printable_path(path), sbp); 2848 if (obj == NULL) 2849 return (NULL); 2850 2851 /* 2852 * If DT_SONAME is present in the object, digest_dynamic2 already 2853 * added it to the object names. 2854 */ 2855 if (name != NULL) 2856 object_add_name(obj, name); 2857 obj->path = path; 2858 if (!digest_dynamic(obj, 0)) 2859 goto errp; 2860 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2861 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2862 if (obj->z_pie && (flags & RTLD_LO_TRACE) == 0) { 2863 dbg("refusing to load PIE executable \"%s\"", obj->path); 2864 _rtld_error("Cannot load PIE binary %s as DSO", obj->path); 2865 goto errp; 2866 } 2867 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2868 RTLD_LO_DLOPEN) { 2869 dbg("refusing to load non-loadable \"%s\"", obj->path); 2870 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2871 goto errp; 2872 } 2873 2874 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2875 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2876 obj_count++; 2877 obj_loads++; 2878 linkmap_add(obj); /* for GDB & dlinfo() */ 2879 max_stack_flags |= obj->stack_flags; 2880 2881 dbg(" %p .. %p: %s", obj->mapbase, 2882 obj->mapbase + obj->mapsize - 1, obj->path); 2883 if (obj->textrel) 2884 dbg(" WARNING: %s has impure text", obj->path); 2885 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2886 obj->path); 2887 2888 return (obj); 2889 2890 errp: 2891 munmap(obj->mapbase, obj->mapsize); 2892 obj_free(obj); 2893 return (NULL); 2894 } 2895 2896 static int 2897 load_kpreload(const void *addr) 2898 { 2899 Obj_Entry *obj; 2900 const Elf_Ehdr *ehdr; 2901 const Elf_Phdr *phdr, *phlimit, *phdyn, *seg0, *segn; 2902 static const char kname[] = "[vdso]"; 2903 2904 ehdr = addr; 2905 if (!check_elf_headers(ehdr, "kpreload")) 2906 return (-1); 2907 obj = obj_new(); 2908 phdr = (const Elf_Phdr *)((const char *)addr + ehdr->e_phoff); 2909 obj->phdr = phdr; 2910 obj->phsize = ehdr->e_phnum * sizeof(*phdr); 2911 phlimit = phdr + ehdr->e_phnum; 2912 seg0 = segn = NULL; 2913 2914 for (; phdr < phlimit; phdr++) { 2915 switch (phdr->p_type) { 2916 case PT_DYNAMIC: 2917 phdyn = phdr; 2918 break; 2919 case PT_GNU_STACK: 2920 /* Absense of PT_GNU_STACK implies stack_flags == 0. */ 2921 obj->stack_flags = phdr->p_flags; 2922 break; 2923 case PT_LOAD: 2924 if (seg0 == NULL || seg0->p_vaddr > phdr->p_vaddr) 2925 seg0 = phdr; 2926 if (segn == NULL || segn->p_vaddr + segn->p_memsz < 2927 phdr->p_vaddr + phdr->p_memsz) 2928 segn = phdr; 2929 break; 2930 } 2931 } 2932 2933 obj->mapbase = __DECONST(caddr_t, addr); 2934 obj->mapsize = segn->p_vaddr + segn->p_memsz - (Elf_Addr)addr; 2935 obj->vaddrbase = 0; 2936 obj->relocbase = obj->mapbase; 2937 2938 object_add_name(obj, kname); 2939 obj->path = xstrdup(kname); 2940 obj->dynamic = (const Elf_Dyn *)(obj->relocbase + phdyn->p_vaddr); 2941 2942 if (!digest_dynamic(obj, 0)) { 2943 obj_free(obj); 2944 return (-1); 2945 } 2946 2947 /* 2948 * We assume that kernel-preloaded object does not need 2949 * relocation. It is currently written into read-only page, 2950 * handling relocations would mean we need to allocate at 2951 * least one additional page per AS. 2952 */ 2953 dbg("%s mapbase %p phdrs %p PT_LOAD phdr %p vaddr %p dynamic %p", 2954 obj->path, obj->mapbase, obj->phdr, seg0, 2955 obj->relocbase + seg0->p_vaddr, obj->dynamic); 2956 2957 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2958 obj_count++; 2959 obj_loads++; 2960 linkmap_add(obj); /* for GDB & dlinfo() */ 2961 max_stack_flags |= obj->stack_flags; 2962 2963 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, 0, 0, obj->path); 2964 return (0); 2965 } 2966 2967 Obj_Entry * 2968 obj_from_addr(const void *addr) 2969 { 2970 Obj_Entry *obj; 2971 2972 TAILQ_FOREACH(obj, &obj_list, next) { 2973 if (obj->marker) 2974 continue; 2975 if (addr < (void *) obj->mapbase) 2976 continue; 2977 if (addr < (void *)(obj->mapbase + obj->mapsize)) 2978 return obj; 2979 } 2980 return (NULL); 2981 } 2982 2983 static void 2984 preinit_main(void) 2985 { 2986 Elf_Addr *preinit_addr; 2987 int index; 2988 2989 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2990 if (preinit_addr == NULL) 2991 return; 2992 2993 for (index = 0; index < obj_main->preinit_array_num; index++) { 2994 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2995 dbg("calling preinit function for %s at %p", obj_main->path, 2996 (void *)preinit_addr[index]); 2997 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2998 0, 0, obj_main->path); 2999 call_init_pointer(obj_main, preinit_addr[index]); 3000 } 3001 } 3002 } 3003 3004 /* 3005 * Call the finalization functions for each of the objects in "list" 3006 * belonging to the DAG of "root" and referenced once. If NULL "root" 3007 * is specified, every finalization function will be called regardless 3008 * of the reference count and the list elements won't be freed. All of 3009 * the objects are expected to have non-NULL fini functions. 3010 */ 3011 static void 3012 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 3013 { 3014 Objlist_Entry *elm; 3015 struct dlerror_save *saved_msg; 3016 Elf_Addr *fini_addr; 3017 int index; 3018 3019 assert(root == NULL || root->refcount == 1); 3020 3021 if (root != NULL) 3022 root->doomed = true; 3023 3024 /* 3025 * Preserve the current error message since a fini function might 3026 * call into the dynamic linker and overwrite it. 3027 */ 3028 saved_msg = errmsg_save(); 3029 do { 3030 STAILQ_FOREACH(elm, list, link) { 3031 if (root != NULL && (elm->obj->refcount != 1 || 3032 objlist_find(&root->dagmembers, elm->obj) == NULL)) 3033 continue; 3034 /* Remove object from fini list to prevent recursive invocation. */ 3035 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 3036 /* Ensure that new references cannot be acquired. */ 3037 elm->obj->doomed = true; 3038 3039 hold_object(elm->obj); 3040 lock_release(rtld_bind_lock, lockstate); 3041 /* 3042 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 3043 * When this happens, DT_FINI_ARRAY is processed first. 3044 */ 3045 fini_addr = (Elf_Addr *)elm->obj->fini_array; 3046 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 3047 for (index = elm->obj->fini_array_num - 1; index >= 0; 3048 index--) { 3049 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 3050 dbg("calling fini function for %s at %p", 3051 elm->obj->path, (void *)fini_addr[index]); 3052 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 3053 (void *)fini_addr[index], 0, 0, elm->obj->path); 3054 call_initfini_pointer(elm->obj, fini_addr[index]); 3055 } 3056 } 3057 } 3058 if (elm->obj->fini != (Elf_Addr)NULL) { 3059 dbg("calling fini function for %s at %p", elm->obj->path, 3060 (void *)elm->obj->fini); 3061 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 3062 0, 0, elm->obj->path); 3063 call_initfini_pointer(elm->obj, elm->obj->fini); 3064 } 3065 wlock_acquire(rtld_bind_lock, lockstate); 3066 unhold_object(elm->obj); 3067 /* No need to free anything if process is going down. */ 3068 if (root != NULL) 3069 free(elm); 3070 /* 3071 * We must restart the list traversal after every fini call 3072 * because a dlclose() call from the fini function or from 3073 * another thread might have modified the reference counts. 3074 */ 3075 break; 3076 } 3077 } while (elm != NULL); 3078 errmsg_restore(saved_msg); 3079 } 3080 3081 /* 3082 * Call the initialization functions for each of the objects in 3083 * "list". All of the objects are expected to have non-NULL init 3084 * functions. 3085 */ 3086 static void 3087 objlist_call_init(Objlist *list, RtldLockState *lockstate) 3088 { 3089 Objlist_Entry *elm; 3090 Obj_Entry *obj; 3091 struct dlerror_save *saved_msg; 3092 Elf_Addr *init_addr; 3093 void (*reg)(void (*)(void)); 3094 int index; 3095 3096 /* 3097 * Clean init_scanned flag so that objects can be rechecked and 3098 * possibly initialized earlier if any of vectors called below 3099 * cause the change by using dlopen. 3100 */ 3101 TAILQ_FOREACH(obj, &obj_list, next) { 3102 if (obj->marker) 3103 continue; 3104 obj->init_scanned = false; 3105 } 3106 3107 /* 3108 * Preserve the current error message since an init function might 3109 * call into the dynamic linker and overwrite it. 3110 */ 3111 saved_msg = errmsg_save(); 3112 STAILQ_FOREACH(elm, list, link) { 3113 if (elm->obj->init_done) /* Initialized early. */ 3114 continue; 3115 /* 3116 * Race: other thread might try to use this object before current 3117 * one completes the initialization. Not much can be done here 3118 * without better locking. 3119 */ 3120 elm->obj->init_done = true; 3121 hold_object(elm->obj); 3122 reg = NULL; 3123 if (elm->obj == obj_main && obj_main->crt_no_init) { 3124 reg = (void (*)(void (*)(void)))get_program_var_addr( 3125 "__libc_atexit", lockstate); 3126 } 3127 lock_release(rtld_bind_lock, lockstate); 3128 if (reg != NULL) { 3129 reg(rtld_exit); 3130 rtld_exit_ptr = rtld_nop_exit; 3131 } 3132 3133 /* 3134 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 3135 * When this happens, DT_INIT is processed first. 3136 */ 3137 if (elm->obj->init != (Elf_Addr)NULL) { 3138 dbg("calling init function for %s at %p", elm->obj->path, 3139 (void *)elm->obj->init); 3140 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 3141 0, 0, elm->obj->path); 3142 call_init_pointer(elm->obj, elm->obj->init); 3143 } 3144 init_addr = (Elf_Addr *)elm->obj->init_array; 3145 if (init_addr != NULL) { 3146 for (index = 0; index < elm->obj->init_array_num; index++) { 3147 if (init_addr[index] != 0 && init_addr[index] != 1) { 3148 dbg("calling init function for %s at %p", elm->obj->path, 3149 (void *)init_addr[index]); 3150 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 3151 (void *)init_addr[index], 0, 0, elm->obj->path); 3152 call_init_pointer(elm->obj, init_addr[index]); 3153 } 3154 } 3155 } 3156 wlock_acquire(rtld_bind_lock, lockstate); 3157 unhold_object(elm->obj); 3158 } 3159 errmsg_restore(saved_msg); 3160 } 3161 3162 static void 3163 objlist_clear(Objlist *list) 3164 { 3165 Objlist_Entry *elm; 3166 3167 while (!STAILQ_EMPTY(list)) { 3168 elm = STAILQ_FIRST(list); 3169 STAILQ_REMOVE_HEAD(list, link); 3170 free(elm); 3171 } 3172 } 3173 3174 static Objlist_Entry * 3175 objlist_find(Objlist *list, const Obj_Entry *obj) 3176 { 3177 Objlist_Entry *elm; 3178 3179 STAILQ_FOREACH(elm, list, link) 3180 if (elm->obj == obj) 3181 return elm; 3182 return (NULL); 3183 } 3184 3185 static void 3186 objlist_init(Objlist *list) 3187 { 3188 STAILQ_INIT(list); 3189 } 3190 3191 static void 3192 objlist_push_head(Objlist *list, Obj_Entry *obj) 3193 { 3194 Objlist_Entry *elm; 3195 3196 elm = NEW(Objlist_Entry); 3197 elm->obj = obj; 3198 STAILQ_INSERT_HEAD(list, elm, link); 3199 } 3200 3201 static void 3202 objlist_push_tail(Objlist *list, Obj_Entry *obj) 3203 { 3204 Objlist_Entry *elm; 3205 3206 elm = NEW(Objlist_Entry); 3207 elm->obj = obj; 3208 STAILQ_INSERT_TAIL(list, elm, link); 3209 } 3210 3211 static void 3212 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 3213 { 3214 Objlist_Entry *elm, *listelm; 3215 3216 STAILQ_FOREACH(listelm, list, link) { 3217 if (listelm->obj == listobj) 3218 break; 3219 } 3220 elm = NEW(Objlist_Entry); 3221 elm->obj = obj; 3222 if (listelm != NULL) 3223 STAILQ_INSERT_AFTER(list, listelm, elm, link); 3224 else 3225 STAILQ_INSERT_TAIL(list, elm, link); 3226 } 3227 3228 static void 3229 objlist_remove(Objlist *list, Obj_Entry *obj) 3230 { 3231 Objlist_Entry *elm; 3232 3233 if ((elm = objlist_find(list, obj)) != NULL) { 3234 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 3235 free(elm); 3236 } 3237 } 3238 3239 /* 3240 * Relocate dag rooted in the specified object. 3241 * Returns 0 on success, or -1 on failure. 3242 */ 3243 3244 static int 3245 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 3246 int flags, RtldLockState *lockstate) 3247 { 3248 Objlist_Entry *elm; 3249 int error; 3250 3251 error = 0; 3252 STAILQ_FOREACH(elm, &root->dagmembers, link) { 3253 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 3254 lockstate); 3255 if (error == -1) 3256 break; 3257 } 3258 return (error); 3259 } 3260 3261 /* 3262 * Prepare for, or clean after, relocating an object marked with 3263 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 3264 * segments are remapped read-write. After relocations are done, the 3265 * segment's permissions are returned back to the modes specified in 3266 * the phdrs. If any relocation happened, or always for wired 3267 * program, COW is triggered. 3268 */ 3269 static int 3270 reloc_textrel_prot(Obj_Entry *obj, bool before) 3271 { 3272 const Elf_Phdr *ph; 3273 void *base; 3274 size_t l, sz; 3275 int prot; 3276 3277 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 3278 l--, ph++) { 3279 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 3280 continue; 3281 base = obj->relocbase + rtld_trunc_page(ph->p_vaddr); 3282 sz = rtld_round_page(ph->p_vaddr + ph->p_filesz) - 3283 rtld_trunc_page(ph->p_vaddr); 3284 prot = before ? (PROT_READ | PROT_WRITE) : 3285 convert_prot(ph->p_flags); 3286 if (mprotect(base, sz, prot) == -1) { 3287 _rtld_error("%s: Cannot write-%sable text segment: %s", 3288 obj->path, before ? "en" : "dis", 3289 rtld_strerror(errno)); 3290 return (-1); 3291 } 3292 } 3293 return (0); 3294 } 3295 3296 /* Process RELR relative relocations. */ 3297 static void 3298 reloc_relr(Obj_Entry *obj) 3299 { 3300 const Elf_Relr *relr, *relrlim; 3301 Elf_Addr *where; 3302 3303 relrlim = (const Elf_Relr *)((const char *)obj->relr + obj->relrsize); 3304 for (relr = obj->relr; relr < relrlim; relr++) { 3305 Elf_Relr entry = *relr; 3306 3307 if ((entry & 1) == 0) { 3308 where = (Elf_Addr *)(obj->relocbase + entry); 3309 *where++ += (Elf_Addr)obj->relocbase; 3310 } else { 3311 for (long i = 0; (entry >>= 1) != 0; i++) 3312 if ((entry & 1) != 0) 3313 where[i] += (Elf_Addr)obj->relocbase; 3314 where += CHAR_BIT * sizeof(Elf_Relr) - 1; 3315 } 3316 } 3317 } 3318 3319 /* 3320 * Relocate single object. 3321 * Returns 0 on success, or -1 on failure. 3322 */ 3323 static int 3324 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 3325 int flags, RtldLockState *lockstate) 3326 { 3327 3328 if (obj->relocated) 3329 return (0); 3330 obj->relocated = true; 3331 if (obj != rtldobj) 3332 dbg("relocating \"%s\"", obj->path); 3333 3334 if (obj->symtab == NULL || obj->strtab == NULL || 3335 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) 3336 dbg("object %s has no run-time symbol table", obj->path); 3337 3338 /* There are relocations to the write-protected text segment. */ 3339 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 3340 return (-1); 3341 3342 /* Process the non-PLT non-IFUNC relocations. */ 3343 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 3344 return (-1); 3345 reloc_relr(obj); 3346 3347 /* Re-protected the text segment. */ 3348 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 3349 return (-1); 3350 3351 /* Set the special PLT or GOT entries. */ 3352 init_pltgot(obj); 3353 3354 /* Process the PLT relocations. */ 3355 if (reloc_plt(obj, flags, lockstate) == -1) 3356 return (-1); 3357 /* Relocate the jump slots if we are doing immediate binding. */ 3358 if ((obj->bind_now || bind_now) && reloc_jmpslots(obj, flags, 3359 lockstate) == -1) 3360 return (-1); 3361 3362 if (!obj->mainprog && obj_enforce_relro(obj) == -1) 3363 return (-1); 3364 3365 /* 3366 * Set up the magic number and version in the Obj_Entry. These 3367 * were checked in the crt1.o from the original ElfKit, so we 3368 * set them for backward compatibility. 3369 */ 3370 obj->magic = RTLD_MAGIC; 3371 obj->version = RTLD_VERSION; 3372 3373 return (0); 3374 } 3375 3376 /* 3377 * Relocate newly-loaded shared objects. The argument is a pointer to 3378 * the Obj_Entry for the first such object. All objects from the first 3379 * to the end of the list of objects are relocated. Returns 0 on success, 3380 * or -1 on failure. 3381 */ 3382 static int 3383 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 3384 int flags, RtldLockState *lockstate) 3385 { 3386 Obj_Entry *obj; 3387 int error; 3388 3389 for (error = 0, obj = first; obj != NULL; 3390 obj = TAILQ_NEXT(obj, next)) { 3391 if (obj->marker) 3392 continue; 3393 error = relocate_object(obj, bind_now, rtldobj, flags, 3394 lockstate); 3395 if (error == -1) 3396 break; 3397 } 3398 return (error); 3399 } 3400 3401 /* 3402 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 3403 * referencing STT_GNU_IFUNC symbols is postponed till the other 3404 * relocations are done. The indirect functions specified as 3405 * ifunc are allowed to call other symbols, so we need to have 3406 * objects relocated before asking for resolution from indirects. 3407 * 3408 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 3409 * instead of the usual lazy handling of PLT slots. It is 3410 * consistent with how GNU does it. 3411 */ 3412 static int 3413 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 3414 RtldLockState *lockstate) 3415 { 3416 3417 if (obj->ifuncs_resolved) 3418 return (0); 3419 obj->ifuncs_resolved = true; 3420 if (!obj->irelative && !obj->irelative_nonplt && 3421 !((obj->bind_now || bind_now) && obj->gnu_ifunc) && 3422 !obj->non_plt_gnu_ifunc) 3423 return (0); 3424 if (obj_disable_relro(obj) == -1 || 3425 (obj->irelative && reloc_iresolve(obj, lockstate) == -1) || 3426 (obj->irelative_nonplt && reloc_iresolve_nonplt(obj, 3427 lockstate) == -1) || 3428 ((obj->bind_now || bind_now) && obj->gnu_ifunc && 3429 reloc_gnu_ifunc(obj, flags, lockstate) == -1) || 3430 (obj->non_plt_gnu_ifunc && reloc_non_plt(obj, &obj_rtld, 3431 flags | SYMLOOK_IFUNC, lockstate) == -1) || 3432 obj_enforce_relro(obj) == -1) 3433 return (-1); 3434 return (0); 3435 } 3436 3437 static int 3438 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 3439 RtldLockState *lockstate) 3440 { 3441 Objlist_Entry *elm; 3442 Obj_Entry *obj; 3443 3444 STAILQ_FOREACH(elm, list, link) { 3445 obj = elm->obj; 3446 if (obj->marker) 3447 continue; 3448 if (resolve_object_ifunc(obj, bind_now, flags, 3449 lockstate) == -1) 3450 return (-1); 3451 } 3452 return (0); 3453 } 3454 3455 /* 3456 * Cleanup procedure. It will be called (by the atexit mechanism) just 3457 * before the process exits. 3458 */ 3459 static void 3460 rtld_exit(void) 3461 { 3462 RtldLockState lockstate; 3463 3464 wlock_acquire(rtld_bind_lock, &lockstate); 3465 dbg("rtld_exit()"); 3466 objlist_call_fini(&list_fini, NULL, &lockstate); 3467 /* No need to remove the items from the list, since we are exiting. */ 3468 if (!libmap_disable) 3469 lm_fini(); 3470 lock_release(rtld_bind_lock, &lockstate); 3471 } 3472 3473 static void 3474 rtld_nop_exit(void) 3475 { 3476 } 3477 3478 /* 3479 * Iterate over a search path, translate each element, and invoke the 3480 * callback on the result. 3481 */ 3482 static void * 3483 path_enumerate(const char *path, path_enum_proc callback, 3484 const char *refobj_path, void *arg) 3485 { 3486 const char *trans; 3487 if (path == NULL) 3488 return (NULL); 3489 3490 path += strspn(path, ":;"); 3491 while (*path != '\0') { 3492 size_t len; 3493 char *res; 3494 3495 len = strcspn(path, ":;"); 3496 trans = lm_findn(refobj_path, path, len); 3497 if (trans) 3498 res = callback(trans, strlen(trans), arg); 3499 else 3500 res = callback(path, len, arg); 3501 3502 if (res != NULL) 3503 return (res); 3504 3505 path += len; 3506 path += strspn(path, ":;"); 3507 } 3508 3509 return (NULL); 3510 } 3511 3512 struct try_library_args { 3513 const char *name; 3514 size_t namelen; 3515 char *buffer; 3516 size_t buflen; 3517 int fd; 3518 }; 3519 3520 static void * 3521 try_library_path(const char *dir, size_t dirlen, void *param) 3522 { 3523 struct try_library_args *arg; 3524 int fd; 3525 3526 arg = param; 3527 if (*dir == '/' || trust) { 3528 char *pathname; 3529 3530 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 3531 return (NULL); 3532 3533 pathname = arg->buffer; 3534 strncpy(pathname, dir, dirlen); 3535 pathname[dirlen] = '/'; 3536 strcpy(pathname + dirlen + 1, arg->name); 3537 3538 dbg(" Trying \"%s\"", pathname); 3539 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY); 3540 if (fd >= 0) { 3541 dbg(" Opened \"%s\", fd %d", pathname, fd); 3542 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 3543 strcpy(pathname, arg->buffer); 3544 arg->fd = fd; 3545 return (pathname); 3546 } else { 3547 dbg(" Failed to open \"%s\": %s", 3548 pathname, rtld_strerror(errno)); 3549 } 3550 } 3551 return (NULL); 3552 } 3553 3554 static char * 3555 search_library_path(const char *name, const char *path, 3556 const char *refobj_path, int *fdp) 3557 { 3558 char *p; 3559 struct try_library_args arg; 3560 3561 if (path == NULL) 3562 return (NULL); 3563 3564 arg.name = name; 3565 arg.namelen = strlen(name); 3566 arg.buffer = xmalloc(PATH_MAX); 3567 arg.buflen = PATH_MAX; 3568 arg.fd = -1; 3569 3570 p = path_enumerate(path, try_library_path, refobj_path, &arg); 3571 *fdp = arg.fd; 3572 3573 free(arg.buffer); 3574 3575 return (p); 3576 } 3577 3578 3579 /* 3580 * Finds the library with the given name using the directory descriptors 3581 * listed in the LD_LIBRARY_PATH_FDS environment variable. 3582 * 3583 * Returns a freshly-opened close-on-exec file descriptor for the library, 3584 * or -1 if the library cannot be found. 3585 */ 3586 static char * 3587 search_library_pathfds(const char *name, const char *path, int *fdp) 3588 { 3589 char *envcopy, *fdstr, *found, *last_token; 3590 size_t len; 3591 int dirfd, fd; 3592 3593 dbg("%s('%s', '%s', fdp)", __func__, name, path); 3594 3595 /* Don't load from user-specified libdirs into setuid binaries. */ 3596 if (!trust) 3597 return (NULL); 3598 3599 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 3600 if (path == NULL) 3601 return (NULL); 3602 3603 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 3604 if (name[0] == '/') { 3605 dbg("Absolute path (%s) passed to %s", name, __func__); 3606 return (NULL); 3607 } 3608 3609 /* 3610 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 3611 * copy of the path, as strtok_r rewrites separator tokens 3612 * with '\0'. 3613 */ 3614 found = NULL; 3615 envcopy = xstrdup(path); 3616 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 3617 fdstr = strtok_r(NULL, ":", &last_token)) { 3618 dirfd = parse_integer(fdstr); 3619 if (dirfd < 0) { 3620 _rtld_error("failed to parse directory FD: '%s'", 3621 fdstr); 3622 break; 3623 } 3624 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 3625 if (fd >= 0) { 3626 *fdp = fd; 3627 len = strlen(fdstr) + strlen(name) + 3; 3628 found = xmalloc(len); 3629 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 3630 _rtld_error("error generating '%d/%s'", 3631 dirfd, name); 3632 rtld_die(); 3633 } 3634 dbg("open('%s') => %d", found, fd); 3635 break; 3636 } 3637 } 3638 free(envcopy); 3639 3640 return (found); 3641 } 3642 3643 3644 int 3645 dlclose(void *handle) 3646 { 3647 RtldLockState lockstate; 3648 int error; 3649 3650 wlock_acquire(rtld_bind_lock, &lockstate); 3651 error = dlclose_locked(handle, &lockstate); 3652 lock_release(rtld_bind_lock, &lockstate); 3653 return (error); 3654 } 3655 3656 static int 3657 dlclose_locked(void *handle, RtldLockState *lockstate) 3658 { 3659 Obj_Entry *root; 3660 3661 root = dlcheck(handle); 3662 if (root == NULL) 3663 return (-1); 3664 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 3665 root->path); 3666 3667 /* Unreference the object and its dependencies. */ 3668 root->dl_refcount--; 3669 3670 if (root->refcount == 1) { 3671 /* 3672 * The object will be no longer referenced, so we must unload it. 3673 * First, call the fini functions. 3674 */ 3675 objlist_call_fini(&list_fini, root, lockstate); 3676 3677 unref_dag(root); 3678 3679 /* Finish cleaning up the newly-unreferenced objects. */ 3680 GDB_STATE(RT_DELETE,&root->linkmap); 3681 unload_object(root, lockstate); 3682 GDB_STATE(RT_CONSISTENT,NULL); 3683 } else 3684 unref_dag(root); 3685 3686 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 3687 return (0); 3688 } 3689 3690 char * 3691 dlerror(void) 3692 { 3693 if (*(lockinfo.dlerror_seen()) != 0) 3694 return (NULL); 3695 *lockinfo.dlerror_seen() = 1; 3696 return (lockinfo.dlerror_loc()); 3697 } 3698 3699 /* 3700 * This function is deprecated and has no effect. 3701 */ 3702 void 3703 dllockinit(void *context, 3704 void *(*_lock_create)(void *context) __unused, 3705 void (*_rlock_acquire)(void *lock) __unused, 3706 void (*_wlock_acquire)(void *lock) __unused, 3707 void (*_lock_release)(void *lock) __unused, 3708 void (*_lock_destroy)(void *lock) __unused, 3709 void (*context_destroy)(void *context)) 3710 { 3711 static void *cur_context; 3712 static void (*cur_context_destroy)(void *); 3713 3714 /* Just destroy the context from the previous call, if necessary. */ 3715 if (cur_context_destroy != NULL) 3716 cur_context_destroy(cur_context); 3717 cur_context = context; 3718 cur_context_destroy = context_destroy; 3719 } 3720 3721 void * 3722 dlopen(const char *name, int mode) 3723 { 3724 3725 return (rtld_dlopen(name, -1, mode)); 3726 } 3727 3728 void * 3729 fdlopen(int fd, int mode) 3730 { 3731 3732 return (rtld_dlopen(NULL, fd, mode)); 3733 } 3734 3735 static void * 3736 rtld_dlopen(const char *name, int fd, int mode) 3737 { 3738 RtldLockState lockstate; 3739 int lo_flags; 3740 3741 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3742 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3743 if (ld_tracing != NULL) { 3744 rlock_acquire(rtld_bind_lock, &lockstate); 3745 if (sigsetjmp(lockstate.env, 0) != 0) 3746 lock_upgrade(rtld_bind_lock, &lockstate); 3747 environ = __DECONST(char **, *get_program_var_addr("environ", &lockstate)); 3748 lock_release(rtld_bind_lock, &lockstate); 3749 } 3750 lo_flags = RTLD_LO_DLOPEN; 3751 if (mode & RTLD_NODELETE) 3752 lo_flags |= RTLD_LO_NODELETE; 3753 if (mode & RTLD_NOLOAD) 3754 lo_flags |= RTLD_LO_NOLOAD; 3755 if (mode & RTLD_DEEPBIND) 3756 lo_flags |= RTLD_LO_DEEPBIND; 3757 if (ld_tracing != NULL) 3758 lo_flags |= RTLD_LO_TRACE | RTLD_LO_IGNSTLS; 3759 3760 return (dlopen_object(name, fd, obj_main, lo_flags, 3761 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3762 } 3763 3764 static void 3765 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate) 3766 { 3767 3768 obj->dl_refcount--; 3769 unref_dag(obj); 3770 if (obj->refcount == 0) 3771 unload_object(obj, lockstate); 3772 } 3773 3774 static Obj_Entry * 3775 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3776 int mode, RtldLockState *lockstate) 3777 { 3778 Obj_Entry *obj; 3779 Objlist initlist; 3780 RtldLockState mlockstate; 3781 int result; 3782 3783 dbg("dlopen_object name \"%s\" fd %d refobj \"%s\" lo_flags %#x mode %#x", 3784 name != NULL ? name : "<null>", fd, refobj == NULL ? "<null>" : 3785 refobj->path, lo_flags, mode); 3786 objlist_init(&initlist); 3787 3788 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3789 wlock_acquire(rtld_bind_lock, &mlockstate); 3790 lockstate = &mlockstate; 3791 } 3792 GDB_STATE(RT_ADD,NULL); 3793 3794 obj = NULL; 3795 if (name == NULL && fd == -1) { 3796 obj = obj_main; 3797 obj->refcount++; 3798 } else { 3799 obj = load_object(name, fd, refobj, lo_flags); 3800 } 3801 3802 if (obj) { 3803 obj->dl_refcount++; 3804 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3805 objlist_push_tail(&list_global, obj); 3806 3807 if (!obj->init_done) { 3808 /* We loaded something new and have to init something. */ 3809 if ((lo_flags & RTLD_LO_DEEPBIND) != 0) 3810 obj->deepbind = true; 3811 result = 0; 3812 if ((lo_flags & (RTLD_LO_EARLY | RTLD_LO_IGNSTLS)) == 0 && 3813 obj->static_tls && !allocate_tls_offset(obj)) { 3814 _rtld_error("%s: No space available " 3815 "for static Thread Local Storage", obj->path); 3816 result = -1; 3817 } 3818 if (result != -1) 3819 result = load_needed_objects(obj, lo_flags & (RTLD_LO_DLOPEN | 3820 RTLD_LO_EARLY | RTLD_LO_IGNSTLS | RTLD_LO_TRACE)); 3821 init_dag(obj); 3822 ref_dag(obj); 3823 if (result != -1) 3824 result = rtld_verify_versions(&obj->dagmembers); 3825 if (result != -1 && ld_tracing) 3826 goto trace; 3827 if (result == -1 || relocate_object_dag(obj, 3828 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3829 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3830 lockstate) == -1) { 3831 dlopen_cleanup(obj, lockstate); 3832 obj = NULL; 3833 } else if (lo_flags & RTLD_LO_EARLY) { 3834 /* 3835 * Do not call the init functions for early loaded 3836 * filtees. The image is still not initialized enough 3837 * for them to work. 3838 * 3839 * Our object is found by the global object list and 3840 * will be ordered among all init calls done right 3841 * before transferring control to main. 3842 */ 3843 } else { 3844 /* Make list of init functions to call. */ 3845 initlist_add_objects(obj, obj, &initlist); 3846 } 3847 /* 3848 * Process all no_delete or global objects here, given 3849 * them own DAGs to prevent their dependencies from being 3850 * unloaded. This has to be done after we have loaded all 3851 * of the dependencies, so that we do not miss any. 3852 */ 3853 if (obj != NULL) 3854 process_z(obj); 3855 } else { 3856 /* 3857 * Bump the reference counts for objects on this DAG. If 3858 * this is the first dlopen() call for the object that was 3859 * already loaded as a dependency, initialize the dag 3860 * starting at it. 3861 */ 3862 init_dag(obj); 3863 ref_dag(obj); 3864 3865 if ((lo_flags & RTLD_LO_TRACE) != 0) 3866 goto trace; 3867 } 3868 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3869 obj->z_nodelete) && !obj->ref_nodel) { 3870 dbg("obj %s nodelete", obj->path); 3871 ref_dag(obj); 3872 obj->z_nodelete = obj->ref_nodel = true; 3873 } 3874 } 3875 3876 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3877 name); 3878 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3879 3880 if ((lo_flags & RTLD_LO_EARLY) == 0) { 3881 map_stacks_exec(lockstate); 3882 if (obj != NULL) 3883 distribute_static_tls(&initlist, lockstate); 3884 } 3885 3886 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3887 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3888 lockstate) == -1) { 3889 objlist_clear(&initlist); 3890 dlopen_cleanup(obj, lockstate); 3891 if (lockstate == &mlockstate) 3892 lock_release(rtld_bind_lock, lockstate); 3893 return (NULL); 3894 } 3895 3896 if (!(lo_flags & RTLD_LO_EARLY)) { 3897 /* Call the init functions. */ 3898 objlist_call_init(&initlist, lockstate); 3899 } 3900 objlist_clear(&initlist); 3901 if (lockstate == &mlockstate) 3902 lock_release(rtld_bind_lock, lockstate); 3903 return (obj); 3904 trace: 3905 trace_loaded_objects(obj, false); 3906 if (lockstate == &mlockstate) 3907 lock_release(rtld_bind_lock, lockstate); 3908 exit(0); 3909 } 3910 3911 static void * 3912 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3913 int flags) 3914 { 3915 DoneList donelist; 3916 const Obj_Entry *obj, *defobj; 3917 const Elf_Sym *def; 3918 SymLook req; 3919 RtldLockState lockstate; 3920 tls_index ti; 3921 void *sym; 3922 int res; 3923 3924 def = NULL; 3925 defobj = NULL; 3926 symlook_init(&req, name); 3927 req.ventry = ve; 3928 req.flags = flags | SYMLOOK_IN_PLT; 3929 req.lockstate = &lockstate; 3930 3931 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3932 rlock_acquire(rtld_bind_lock, &lockstate); 3933 if (sigsetjmp(lockstate.env, 0) != 0) 3934 lock_upgrade(rtld_bind_lock, &lockstate); 3935 if (handle == NULL || handle == RTLD_NEXT || 3936 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3937 3938 if ((obj = obj_from_addr(retaddr)) == NULL) { 3939 _rtld_error("Cannot determine caller's shared object"); 3940 lock_release(rtld_bind_lock, &lockstate); 3941 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3942 return (NULL); 3943 } 3944 if (handle == NULL) { /* Just the caller's shared object. */ 3945 res = symlook_obj(&req, obj); 3946 if (res == 0) { 3947 def = req.sym_out; 3948 defobj = req.defobj_out; 3949 } 3950 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3951 handle == RTLD_SELF) { /* ... caller included */ 3952 if (handle == RTLD_NEXT) 3953 obj = globallist_next(obj); 3954 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3955 if (obj->marker) 3956 continue; 3957 res = symlook_obj(&req, obj); 3958 if (res == 0) { 3959 if (def == NULL || (ld_dynamic_weak && 3960 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK)) { 3961 def = req.sym_out; 3962 defobj = req.defobj_out; 3963 if (!ld_dynamic_weak || 3964 ELF_ST_BIND(def->st_info) != STB_WEAK) 3965 break; 3966 } 3967 } 3968 } 3969 /* 3970 * Search the dynamic linker itself, and possibly resolve the 3971 * symbol from there. This is how the application links to 3972 * dynamic linker services such as dlopen. 3973 * Note that we ignore ld_dynamic_weak == false case, 3974 * always overriding weak symbols by rtld definitions. 3975 */ 3976 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3977 res = symlook_obj(&req, &obj_rtld); 3978 if (res == 0) { 3979 def = req.sym_out; 3980 defobj = req.defobj_out; 3981 } 3982 } 3983 } else { 3984 assert(handle == RTLD_DEFAULT); 3985 res = symlook_default(&req, obj); 3986 if (res == 0) { 3987 defobj = req.defobj_out; 3988 def = req.sym_out; 3989 } 3990 } 3991 } else { 3992 if ((obj = dlcheck(handle)) == NULL) { 3993 lock_release(rtld_bind_lock, &lockstate); 3994 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3995 return (NULL); 3996 } 3997 3998 donelist_init(&donelist); 3999 if (obj->mainprog) { 4000 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 4001 res = symlook_global(&req, &donelist); 4002 if (res == 0) { 4003 def = req.sym_out; 4004 defobj = req.defobj_out; 4005 } 4006 /* 4007 * Search the dynamic linker itself, and possibly resolve the 4008 * symbol from there. This is how the application links to 4009 * dynamic linker services such as dlopen. 4010 */ 4011 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 4012 res = symlook_obj(&req, &obj_rtld); 4013 if (res == 0) { 4014 def = req.sym_out; 4015 defobj = req.defobj_out; 4016 } 4017 } 4018 } 4019 else { 4020 /* Search the whole DAG rooted at the given object. */ 4021 res = symlook_list(&req, &obj->dagmembers, &donelist); 4022 if (res == 0) { 4023 def = req.sym_out; 4024 defobj = req.defobj_out; 4025 } 4026 } 4027 } 4028 4029 if (def != NULL) { 4030 lock_release(rtld_bind_lock, &lockstate); 4031 4032 /* 4033 * The value required by the caller is derived from the value 4034 * of the symbol. this is simply the relocated value of the 4035 * symbol. 4036 */ 4037 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 4038 sym = make_function_pointer(def, defobj); 4039 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 4040 sym = rtld_resolve_ifunc(defobj, def); 4041 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 4042 ti.ti_module = defobj->tlsindex; 4043 ti.ti_offset = def->st_value; 4044 sym = __tls_get_addr(&ti); 4045 } else 4046 sym = defobj->relocbase + def->st_value; 4047 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 4048 return (sym); 4049 } 4050 4051 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "", 4052 ve != NULL ? ve->name : ""); 4053 lock_release(rtld_bind_lock, &lockstate); 4054 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 4055 return (NULL); 4056 } 4057 4058 void * 4059 dlsym(void *handle, const char *name) 4060 { 4061 return (do_dlsym(handle, name, __builtin_return_address(0), NULL, 4062 SYMLOOK_DLSYM)); 4063 } 4064 4065 dlfunc_t 4066 dlfunc(void *handle, const char *name) 4067 { 4068 union { 4069 void *d; 4070 dlfunc_t f; 4071 } rv; 4072 4073 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 4074 SYMLOOK_DLSYM); 4075 return (rv.f); 4076 } 4077 4078 void * 4079 dlvsym(void *handle, const char *name, const char *version) 4080 { 4081 Ver_Entry ventry; 4082 4083 ventry.name = version; 4084 ventry.file = NULL; 4085 ventry.hash = elf_hash(version); 4086 ventry.flags= 0; 4087 return (do_dlsym(handle, name, __builtin_return_address(0), &ventry, 4088 SYMLOOK_DLSYM)); 4089 } 4090 4091 int 4092 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 4093 { 4094 const Obj_Entry *obj; 4095 RtldLockState lockstate; 4096 4097 rlock_acquire(rtld_bind_lock, &lockstate); 4098 obj = obj_from_addr(addr); 4099 if (obj == NULL) { 4100 _rtld_error("No shared object contains address"); 4101 lock_release(rtld_bind_lock, &lockstate); 4102 return (0); 4103 } 4104 rtld_fill_dl_phdr_info(obj, phdr_info); 4105 lock_release(rtld_bind_lock, &lockstate); 4106 return (1); 4107 } 4108 4109 int 4110 dladdr(const void *addr, Dl_info *info) 4111 { 4112 const Obj_Entry *obj; 4113 const Elf_Sym *def; 4114 void *symbol_addr; 4115 unsigned long symoffset; 4116 RtldLockState lockstate; 4117 4118 rlock_acquire(rtld_bind_lock, &lockstate); 4119 obj = obj_from_addr(addr); 4120 if (obj == NULL) { 4121 _rtld_error("No shared object contains address"); 4122 lock_release(rtld_bind_lock, &lockstate); 4123 return (0); 4124 } 4125 info->dli_fname = obj->path; 4126 info->dli_fbase = obj->mapbase; 4127 info->dli_saddr = (void *)0; 4128 info->dli_sname = NULL; 4129 4130 /* 4131 * Walk the symbol list looking for the symbol whose address is 4132 * closest to the address sent in. 4133 */ 4134 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 4135 def = obj->symtab + symoffset; 4136 4137 /* 4138 * For skip the symbol if st_shndx is either SHN_UNDEF or 4139 * SHN_COMMON. 4140 */ 4141 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 4142 continue; 4143 4144 /* 4145 * If the symbol is greater than the specified address, or if it 4146 * is further away from addr than the current nearest symbol, 4147 * then reject it. 4148 */ 4149 symbol_addr = obj->relocbase + def->st_value; 4150 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 4151 continue; 4152 4153 /* Update our idea of the nearest symbol. */ 4154 info->dli_sname = obj->strtab + def->st_name; 4155 info->dli_saddr = symbol_addr; 4156 4157 /* Exact match? */ 4158 if (info->dli_saddr == addr) 4159 break; 4160 } 4161 lock_release(rtld_bind_lock, &lockstate); 4162 return (1); 4163 } 4164 4165 int 4166 dlinfo(void *handle, int request, void *p) 4167 { 4168 const Obj_Entry *obj; 4169 RtldLockState lockstate; 4170 int error; 4171 4172 rlock_acquire(rtld_bind_lock, &lockstate); 4173 4174 if (handle == NULL || handle == RTLD_SELF) { 4175 void *retaddr; 4176 4177 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 4178 if ((obj = obj_from_addr(retaddr)) == NULL) 4179 _rtld_error("Cannot determine caller's shared object"); 4180 } else 4181 obj = dlcheck(handle); 4182 4183 if (obj == NULL) { 4184 lock_release(rtld_bind_lock, &lockstate); 4185 return (-1); 4186 } 4187 4188 error = 0; 4189 switch (request) { 4190 case RTLD_DI_LINKMAP: 4191 *((struct link_map const **)p) = &obj->linkmap; 4192 break; 4193 case RTLD_DI_ORIGIN: 4194 error = rtld_dirname(obj->path, p); 4195 break; 4196 4197 case RTLD_DI_SERINFOSIZE: 4198 case RTLD_DI_SERINFO: 4199 error = do_search_info(obj, request, (struct dl_serinfo *)p); 4200 break; 4201 4202 default: 4203 _rtld_error("Invalid request %d passed to dlinfo()", request); 4204 error = -1; 4205 } 4206 4207 lock_release(rtld_bind_lock, &lockstate); 4208 4209 return (error); 4210 } 4211 4212 static void 4213 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 4214 { 4215 uintptr_t **dtvp; 4216 4217 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 4218 phdr_info->dlpi_name = obj->path; 4219 phdr_info->dlpi_phdr = obj->phdr; 4220 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 4221 phdr_info->dlpi_tls_modid = obj->tlsindex; 4222 dtvp = &_tcb_get()->tcb_dtv; 4223 phdr_info->dlpi_tls_data = (char *)tls_get_addr_slow(dtvp, 4224 obj->tlsindex, 0, true) + TLS_DTV_OFFSET; 4225 phdr_info->dlpi_adds = obj_loads; 4226 phdr_info->dlpi_subs = obj_loads - obj_count; 4227 } 4228 4229 int 4230 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 4231 { 4232 struct dl_phdr_info phdr_info; 4233 Obj_Entry *obj, marker; 4234 RtldLockState bind_lockstate, phdr_lockstate; 4235 int error; 4236 4237 init_marker(&marker); 4238 error = 0; 4239 4240 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 4241 wlock_acquire(rtld_bind_lock, &bind_lockstate); 4242 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 4243 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 4244 rtld_fill_dl_phdr_info(obj, &phdr_info); 4245 hold_object(obj); 4246 lock_release(rtld_bind_lock, &bind_lockstate); 4247 4248 error = callback(&phdr_info, sizeof phdr_info, param); 4249 4250 wlock_acquire(rtld_bind_lock, &bind_lockstate); 4251 unhold_object(obj); 4252 obj = globallist_next(&marker); 4253 TAILQ_REMOVE(&obj_list, &marker, next); 4254 if (error != 0) { 4255 lock_release(rtld_bind_lock, &bind_lockstate); 4256 lock_release(rtld_phdr_lock, &phdr_lockstate); 4257 return (error); 4258 } 4259 } 4260 4261 if (error == 0) { 4262 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 4263 lock_release(rtld_bind_lock, &bind_lockstate); 4264 error = callback(&phdr_info, sizeof(phdr_info), param); 4265 } 4266 lock_release(rtld_phdr_lock, &phdr_lockstate); 4267 return (error); 4268 } 4269 4270 static void * 4271 fill_search_info(const char *dir, size_t dirlen, void *param) 4272 { 4273 struct fill_search_info_args *arg; 4274 4275 arg = param; 4276 4277 if (arg->request == RTLD_DI_SERINFOSIZE) { 4278 arg->serinfo->dls_cnt ++; 4279 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 4280 } else { 4281 struct dl_serpath *s_entry; 4282 4283 s_entry = arg->serpath; 4284 s_entry->dls_name = arg->strspace; 4285 s_entry->dls_flags = arg->flags; 4286 4287 strncpy(arg->strspace, dir, dirlen); 4288 arg->strspace[dirlen] = '\0'; 4289 4290 arg->strspace += dirlen + 1; 4291 arg->serpath++; 4292 } 4293 4294 return (NULL); 4295 } 4296 4297 static int 4298 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 4299 { 4300 struct dl_serinfo _info; 4301 struct fill_search_info_args args; 4302 4303 args.request = RTLD_DI_SERINFOSIZE; 4304 args.serinfo = &_info; 4305 4306 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 4307 _info.dls_cnt = 0; 4308 4309 path_enumerate(obj->rpath, fill_search_info, NULL, &args); 4310 path_enumerate(ld_library_path, fill_search_info, NULL, &args); 4311 path_enumerate(obj->runpath, fill_search_info, NULL, &args); 4312 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args); 4313 if (!obj->z_nodeflib) 4314 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args); 4315 4316 4317 if (request == RTLD_DI_SERINFOSIZE) { 4318 info->dls_size = _info.dls_size; 4319 info->dls_cnt = _info.dls_cnt; 4320 return (0); 4321 } 4322 4323 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 4324 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 4325 return (-1); 4326 } 4327 4328 args.request = RTLD_DI_SERINFO; 4329 args.serinfo = info; 4330 args.serpath = &info->dls_serpath[0]; 4331 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 4332 4333 args.flags = LA_SER_RUNPATH; 4334 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL) 4335 return (-1); 4336 4337 args.flags = LA_SER_LIBPATH; 4338 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL) 4339 return (-1); 4340 4341 args.flags = LA_SER_RUNPATH; 4342 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL) 4343 return (-1); 4344 4345 args.flags = LA_SER_CONFIG; 4346 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args) 4347 != NULL) 4348 return (-1); 4349 4350 args.flags = LA_SER_DEFAULT; 4351 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path, 4352 fill_search_info, NULL, &args) != NULL) 4353 return (-1); 4354 return (0); 4355 } 4356 4357 static int 4358 rtld_dirname(const char *path, char *bname) 4359 { 4360 const char *endp; 4361 4362 /* Empty or NULL string gets treated as "." */ 4363 if (path == NULL || *path == '\0') { 4364 bname[0] = '.'; 4365 bname[1] = '\0'; 4366 return (0); 4367 } 4368 4369 /* Strip trailing slashes */ 4370 endp = path + strlen(path) - 1; 4371 while (endp > path && *endp == '/') 4372 endp--; 4373 4374 /* Find the start of the dir */ 4375 while (endp > path && *endp != '/') 4376 endp--; 4377 4378 /* Either the dir is "/" or there are no slashes */ 4379 if (endp == path) { 4380 bname[0] = *endp == '/' ? '/' : '.'; 4381 bname[1] = '\0'; 4382 return (0); 4383 } else { 4384 do { 4385 endp--; 4386 } while (endp > path && *endp == '/'); 4387 } 4388 4389 if (endp - path + 2 > PATH_MAX) 4390 { 4391 _rtld_error("Filename is too long: %s", path); 4392 return(-1); 4393 } 4394 4395 strncpy(bname, path, endp - path + 1); 4396 bname[endp - path + 1] = '\0'; 4397 return (0); 4398 } 4399 4400 static int 4401 rtld_dirname_abs(const char *path, char *base) 4402 { 4403 char *last; 4404 4405 if (realpath(path, base) == NULL) { 4406 _rtld_error("realpath \"%s\" failed (%s)", path, 4407 rtld_strerror(errno)); 4408 return (-1); 4409 } 4410 dbg("%s -> %s", path, base); 4411 last = strrchr(base, '/'); 4412 if (last == NULL) { 4413 _rtld_error("non-abs result from realpath \"%s\"", path); 4414 return (-1); 4415 } 4416 if (last != base) 4417 *last = '\0'; 4418 return (0); 4419 } 4420 4421 static void 4422 linkmap_add(Obj_Entry *obj) 4423 { 4424 struct link_map *l, *prev; 4425 4426 l = &obj->linkmap; 4427 l->l_name = obj->path; 4428 l->l_base = obj->mapbase; 4429 l->l_ld = obj->dynamic; 4430 l->l_addr = obj->relocbase; 4431 4432 if (r_debug.r_map == NULL) { 4433 r_debug.r_map = l; 4434 return; 4435 } 4436 4437 /* 4438 * Scan to the end of the list, but not past the entry for the 4439 * dynamic linker, which we want to keep at the very end. 4440 */ 4441 for (prev = r_debug.r_map; 4442 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 4443 prev = prev->l_next) 4444 ; 4445 4446 /* Link in the new entry. */ 4447 l->l_prev = prev; 4448 l->l_next = prev->l_next; 4449 if (l->l_next != NULL) 4450 l->l_next->l_prev = l; 4451 prev->l_next = l; 4452 } 4453 4454 static void 4455 linkmap_delete(Obj_Entry *obj) 4456 { 4457 struct link_map *l; 4458 4459 l = &obj->linkmap; 4460 if (l->l_prev == NULL) { 4461 if ((r_debug.r_map = l->l_next) != NULL) 4462 l->l_next->l_prev = NULL; 4463 return; 4464 } 4465 4466 if ((l->l_prev->l_next = l->l_next) != NULL) 4467 l->l_next->l_prev = l->l_prev; 4468 } 4469 4470 /* 4471 * Function for the debugger to set a breakpoint on to gain control. 4472 * 4473 * The two parameters allow the debugger to easily find and determine 4474 * what the runtime loader is doing and to whom it is doing it. 4475 * 4476 * When the loadhook trap is hit (r_debug_state, set at program 4477 * initialization), the arguments can be found on the stack: 4478 * 4479 * +8 struct link_map *m 4480 * +4 struct r_debug *rd 4481 * +0 RetAddr 4482 */ 4483 void 4484 r_debug_state(struct r_debug* rd __unused, struct link_map *m __unused) 4485 { 4486 /* 4487 * The following is a hack to force the compiler to emit calls to 4488 * this function, even when optimizing. If the function is empty, 4489 * the compiler is not obliged to emit any code for calls to it, 4490 * even when marked __noinline. However, gdb depends on those 4491 * calls being made. 4492 */ 4493 __compiler_membar(); 4494 } 4495 4496 /* 4497 * A function called after init routines have completed. This can be used to 4498 * break before a program's entry routine is called, and can be used when 4499 * main is not available in the symbol table. 4500 */ 4501 void 4502 _r_debug_postinit(struct link_map *m __unused) 4503 { 4504 4505 /* See r_debug_state(). */ 4506 __compiler_membar(); 4507 } 4508 4509 static void 4510 release_object(Obj_Entry *obj) 4511 { 4512 4513 if (obj->holdcount > 0) { 4514 obj->unholdfree = true; 4515 return; 4516 } 4517 munmap(obj->mapbase, obj->mapsize); 4518 linkmap_delete(obj); 4519 obj_free(obj); 4520 } 4521 4522 /* 4523 * Get address of the pointer variable in the main program. 4524 * Prefer non-weak symbol over the weak one. 4525 */ 4526 static const void ** 4527 get_program_var_addr(const char *name, RtldLockState *lockstate) 4528 { 4529 SymLook req; 4530 DoneList donelist; 4531 4532 symlook_init(&req, name); 4533 req.lockstate = lockstate; 4534 donelist_init(&donelist); 4535 if (symlook_global(&req, &donelist) != 0) 4536 return (NULL); 4537 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 4538 return ((const void **)make_function_pointer(req.sym_out, 4539 req.defobj_out)); 4540 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 4541 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 4542 else 4543 return ((const void **)(req.defobj_out->relocbase + 4544 req.sym_out->st_value)); 4545 } 4546 4547 /* 4548 * Set a pointer variable in the main program to the given value. This 4549 * is used to set key variables such as "environ" before any of the 4550 * init functions are called. 4551 */ 4552 static void 4553 set_program_var(const char *name, const void *value) 4554 { 4555 const void **addr; 4556 4557 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 4558 dbg("\"%s\": *%p <-- %p", name, addr, value); 4559 *addr = value; 4560 } 4561 } 4562 4563 /* 4564 * Search the global objects, including dependencies and main object, 4565 * for the given symbol. 4566 */ 4567 static int 4568 symlook_global(SymLook *req, DoneList *donelist) 4569 { 4570 SymLook req1; 4571 const Objlist_Entry *elm; 4572 int res; 4573 4574 symlook_init_from_req(&req1, req); 4575 4576 /* Search all objects loaded at program start up. */ 4577 if (req->defobj_out == NULL || (ld_dynamic_weak && 4578 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK)) { 4579 res = symlook_list(&req1, &list_main, donelist); 4580 if (res == 0 && (!ld_dynamic_weak || req->defobj_out == NULL || 4581 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4582 req->sym_out = req1.sym_out; 4583 req->defobj_out = req1.defobj_out; 4584 assert(req->defobj_out != NULL); 4585 } 4586 } 4587 4588 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 4589 STAILQ_FOREACH(elm, &list_global, link) { 4590 if (req->defobj_out != NULL && (!ld_dynamic_weak || 4591 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)) 4592 break; 4593 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 4594 if (res == 0 && (req->defobj_out == NULL || 4595 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4596 req->sym_out = req1.sym_out; 4597 req->defobj_out = req1.defobj_out; 4598 assert(req->defobj_out != NULL); 4599 } 4600 } 4601 4602 return (req->sym_out != NULL ? 0 : ESRCH); 4603 } 4604 4605 /* 4606 * Given a symbol name in a referencing object, find the corresponding 4607 * definition of the symbol. Returns a pointer to the symbol, or NULL if 4608 * no definition was found. Returns a pointer to the Obj_Entry of the 4609 * defining object via the reference parameter DEFOBJ_OUT. 4610 */ 4611 static int 4612 symlook_default(SymLook *req, const Obj_Entry *refobj) 4613 { 4614 DoneList donelist; 4615 const Objlist_Entry *elm; 4616 SymLook req1; 4617 int res; 4618 4619 donelist_init(&donelist); 4620 symlook_init_from_req(&req1, req); 4621 4622 /* 4623 * Look first in the referencing object if linked symbolically, 4624 * and similarly handle protected symbols. 4625 */ 4626 res = symlook_obj(&req1, refobj); 4627 if (res == 0 && (refobj->symbolic || 4628 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) { 4629 req->sym_out = req1.sym_out; 4630 req->defobj_out = req1.defobj_out; 4631 assert(req->defobj_out != NULL); 4632 } 4633 if (refobj->symbolic || req->defobj_out != NULL) 4634 donelist_check(&donelist, refobj); 4635 4636 if (!refobj->deepbind) 4637 symlook_global(req, &donelist); 4638 4639 /* Search all dlopened DAGs containing the referencing object. */ 4640 STAILQ_FOREACH(elm, &refobj->dldags, link) { 4641 if (req->sym_out != NULL && (!ld_dynamic_weak || 4642 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)) 4643 break; 4644 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 4645 if (res == 0 && (req->sym_out == NULL || 4646 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4647 req->sym_out = req1.sym_out; 4648 req->defobj_out = req1.defobj_out; 4649 assert(req->defobj_out != NULL); 4650 } 4651 } 4652 4653 if (refobj->deepbind) 4654 symlook_global(req, &donelist); 4655 4656 /* 4657 * Search the dynamic linker itself, and possibly resolve the 4658 * symbol from there. This is how the application links to 4659 * dynamic linker services such as dlopen. 4660 */ 4661 if (req->sym_out == NULL || 4662 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4663 res = symlook_obj(&req1, &obj_rtld); 4664 if (res == 0) { 4665 req->sym_out = req1.sym_out; 4666 req->defobj_out = req1.defobj_out; 4667 assert(req->defobj_out != NULL); 4668 } 4669 } 4670 4671 return (req->sym_out != NULL ? 0 : ESRCH); 4672 } 4673 4674 static int 4675 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 4676 { 4677 const Elf_Sym *def; 4678 const Obj_Entry *defobj; 4679 const Objlist_Entry *elm; 4680 SymLook req1; 4681 int res; 4682 4683 def = NULL; 4684 defobj = NULL; 4685 STAILQ_FOREACH(elm, objlist, link) { 4686 if (donelist_check(dlp, elm->obj)) 4687 continue; 4688 symlook_init_from_req(&req1, req); 4689 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 4690 if (def == NULL || (ld_dynamic_weak && 4691 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4692 def = req1.sym_out; 4693 defobj = req1.defobj_out; 4694 if (!ld_dynamic_weak || ELF_ST_BIND(def->st_info) != STB_WEAK) 4695 break; 4696 } 4697 } 4698 } 4699 if (def != NULL) { 4700 req->sym_out = def; 4701 req->defobj_out = defobj; 4702 return (0); 4703 } 4704 return (ESRCH); 4705 } 4706 4707 /* 4708 * Search the chain of DAGS cointed to by the given Needed_Entry 4709 * for a symbol of the given name. Each DAG is scanned completely 4710 * before advancing to the next one. Returns a pointer to the symbol, 4711 * or NULL if no definition was found. 4712 */ 4713 static int 4714 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 4715 { 4716 const Elf_Sym *def; 4717 const Needed_Entry *n; 4718 const Obj_Entry *defobj; 4719 SymLook req1; 4720 int res; 4721 4722 def = NULL; 4723 defobj = NULL; 4724 symlook_init_from_req(&req1, req); 4725 for (n = needed; n != NULL; n = n->next) { 4726 if (n->obj == NULL || 4727 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 4728 continue; 4729 if (def == NULL || (ld_dynamic_weak && 4730 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4731 def = req1.sym_out; 4732 defobj = req1.defobj_out; 4733 if (!ld_dynamic_weak || ELF_ST_BIND(def->st_info) != STB_WEAK) 4734 break; 4735 } 4736 } 4737 if (def != NULL) { 4738 req->sym_out = def; 4739 req->defobj_out = defobj; 4740 return (0); 4741 } 4742 return (ESRCH); 4743 } 4744 4745 static int 4746 symlook_obj_load_filtees(SymLook *req, SymLook *req1, const Obj_Entry *obj, 4747 Needed_Entry *needed) 4748 { 4749 DoneList donelist; 4750 int flags; 4751 4752 flags = (req->flags & SYMLOOK_EARLY) != 0 ? RTLD_LO_EARLY : 0; 4753 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4754 donelist_init(&donelist); 4755 symlook_init_from_req(req1, req); 4756 return (symlook_needed(req1, needed, &donelist)); 4757 } 4758 4759 /* 4760 * Search the symbol table of a single shared object for a symbol of 4761 * the given name and version, if requested. Returns a pointer to the 4762 * symbol, or NULL if no definition was found. If the object is 4763 * filter, return filtered symbol from filtee. 4764 * 4765 * The symbol's hash value is passed in for efficiency reasons; that 4766 * eliminates many recomputations of the hash value. 4767 */ 4768 int 4769 symlook_obj(SymLook *req, const Obj_Entry *obj) 4770 { 4771 SymLook req1; 4772 int res, mres; 4773 4774 /* 4775 * If there is at least one valid hash at this point, we prefer to 4776 * use the faster GNU version if available. 4777 */ 4778 if (obj->valid_hash_gnu) 4779 mres = symlook_obj1_gnu(req, obj); 4780 else if (obj->valid_hash_sysv) 4781 mres = symlook_obj1_sysv(req, obj); 4782 else 4783 return (EINVAL); 4784 4785 if (mres == 0) { 4786 if (obj->needed_filtees != NULL) { 4787 res = symlook_obj_load_filtees(req, &req1, obj, 4788 obj->needed_filtees); 4789 if (res == 0) { 4790 req->sym_out = req1.sym_out; 4791 req->defobj_out = req1.defobj_out; 4792 } 4793 return (res); 4794 } 4795 if (obj->needed_aux_filtees != NULL) { 4796 res = symlook_obj_load_filtees(req, &req1, obj, 4797 obj->needed_aux_filtees); 4798 if (res == 0) { 4799 req->sym_out = req1.sym_out; 4800 req->defobj_out = req1.defobj_out; 4801 return (res); 4802 } 4803 } 4804 } 4805 return (mres); 4806 } 4807 4808 /* Symbol match routine common to both hash functions */ 4809 static bool 4810 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4811 const unsigned long symnum) 4812 { 4813 Elf_Versym verndx; 4814 const Elf_Sym *symp; 4815 const char *strp; 4816 4817 symp = obj->symtab + symnum; 4818 strp = obj->strtab + symp->st_name; 4819 4820 switch (ELF_ST_TYPE(symp->st_info)) { 4821 case STT_FUNC: 4822 case STT_NOTYPE: 4823 case STT_OBJECT: 4824 case STT_COMMON: 4825 case STT_GNU_IFUNC: 4826 if (symp->st_value == 0) 4827 return (false); 4828 /* fallthrough */ 4829 case STT_TLS: 4830 if (symp->st_shndx != SHN_UNDEF) 4831 break; 4832 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4833 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4834 break; 4835 /* fallthrough */ 4836 default: 4837 return (false); 4838 } 4839 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4840 return (false); 4841 4842 if (req->ventry == NULL) { 4843 if (obj->versyms != NULL) { 4844 verndx = VER_NDX(obj->versyms[symnum]); 4845 if (verndx > obj->vernum) { 4846 _rtld_error( 4847 "%s: symbol %s references wrong version %d", 4848 obj->path, obj->strtab + symnum, verndx); 4849 return (false); 4850 } 4851 /* 4852 * If we are not called from dlsym (i.e. this 4853 * is a normal relocation from unversioned 4854 * binary), accept the symbol immediately if 4855 * it happens to have first version after this 4856 * shared object became versioned. Otherwise, 4857 * if symbol is versioned and not hidden, 4858 * remember it. If it is the only symbol with 4859 * this name exported by the shared object, it 4860 * will be returned as a match by the calling 4861 * function. If symbol is global (verndx < 2) 4862 * accept it unconditionally. 4863 */ 4864 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4865 verndx == VER_NDX_GIVEN) { 4866 result->sym_out = symp; 4867 return (true); 4868 } 4869 else if (verndx >= VER_NDX_GIVEN) { 4870 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4871 == 0) { 4872 if (result->vsymp == NULL) 4873 result->vsymp = symp; 4874 result->vcount++; 4875 } 4876 return (false); 4877 } 4878 } 4879 result->sym_out = symp; 4880 return (true); 4881 } 4882 if (obj->versyms == NULL) { 4883 if (object_match_name(obj, req->ventry->name)) { 4884 _rtld_error("%s: object %s should provide version %s " 4885 "for symbol %s", obj_rtld.path, obj->path, 4886 req->ventry->name, obj->strtab + symnum); 4887 return (false); 4888 } 4889 } else { 4890 verndx = VER_NDX(obj->versyms[symnum]); 4891 if (verndx > obj->vernum) { 4892 _rtld_error("%s: symbol %s references wrong version %d", 4893 obj->path, obj->strtab + symnum, verndx); 4894 return (false); 4895 } 4896 if (obj->vertab[verndx].hash != req->ventry->hash || 4897 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4898 /* 4899 * Version does not match. Look if this is a 4900 * global symbol and if it is not hidden. If 4901 * global symbol (verndx < 2) is available, 4902 * use it. Do not return symbol if we are 4903 * called by dlvsym, because dlvsym looks for 4904 * a specific version and default one is not 4905 * what dlvsym wants. 4906 */ 4907 if ((req->flags & SYMLOOK_DLSYM) || 4908 (verndx >= VER_NDX_GIVEN) || 4909 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4910 return (false); 4911 } 4912 } 4913 result->sym_out = symp; 4914 return (true); 4915 } 4916 4917 /* 4918 * Search for symbol using SysV hash function. 4919 * obj->buckets is known not to be NULL at this point; the test for this was 4920 * performed with the obj->valid_hash_sysv assignment. 4921 */ 4922 static int 4923 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4924 { 4925 unsigned long symnum; 4926 Sym_Match_Result matchres; 4927 4928 matchres.sym_out = NULL; 4929 matchres.vsymp = NULL; 4930 matchres.vcount = 0; 4931 4932 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4933 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4934 if (symnum >= obj->nchains) 4935 return (ESRCH); /* Bad object */ 4936 4937 if (matched_symbol(req, obj, &matchres, symnum)) { 4938 req->sym_out = matchres.sym_out; 4939 req->defobj_out = obj; 4940 return (0); 4941 } 4942 } 4943 if (matchres.vcount == 1) { 4944 req->sym_out = matchres.vsymp; 4945 req->defobj_out = obj; 4946 return (0); 4947 } 4948 return (ESRCH); 4949 } 4950 4951 /* Search for symbol using GNU hash function */ 4952 static int 4953 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4954 { 4955 Elf_Addr bloom_word; 4956 const Elf32_Word *hashval; 4957 Elf32_Word bucket; 4958 Sym_Match_Result matchres; 4959 unsigned int h1, h2; 4960 unsigned long symnum; 4961 4962 matchres.sym_out = NULL; 4963 matchres.vsymp = NULL; 4964 matchres.vcount = 0; 4965 4966 /* Pick right bitmask word from Bloom filter array */ 4967 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4968 obj->maskwords_bm_gnu]; 4969 4970 /* Calculate modulus word size of gnu hash and its derivative */ 4971 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4972 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4973 4974 /* Filter out the "definitely not in set" queries */ 4975 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4976 return (ESRCH); 4977 4978 /* Locate hash chain and corresponding value element*/ 4979 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4980 if (bucket == 0) 4981 return (ESRCH); 4982 hashval = &obj->chain_zero_gnu[bucket]; 4983 do { 4984 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4985 symnum = hashval - obj->chain_zero_gnu; 4986 if (matched_symbol(req, obj, &matchres, symnum)) { 4987 req->sym_out = matchres.sym_out; 4988 req->defobj_out = obj; 4989 return (0); 4990 } 4991 } 4992 } while ((*hashval++ & 1) == 0); 4993 if (matchres.vcount == 1) { 4994 req->sym_out = matchres.vsymp; 4995 req->defobj_out = obj; 4996 return (0); 4997 } 4998 return (ESRCH); 4999 } 5000 5001 static void 5002 trace_calc_fmts(const char **main_local, const char **fmt1, const char **fmt2) 5003 { 5004 *main_local = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_PROGNAME); 5005 if (*main_local == NULL) 5006 *main_local = ""; 5007 5008 *fmt1 = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT1); 5009 if (*fmt1 == NULL) 5010 *fmt1 = "\t%o => %p (%x)\n"; 5011 5012 *fmt2 = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT2); 5013 if (*fmt2 == NULL) 5014 *fmt2 = "\t%o (%x)\n"; 5015 } 5016 5017 static void 5018 trace_print_obj(Obj_Entry *obj, const char *name, const char *path, 5019 const char *main_local, const char *fmt1, const char *fmt2) 5020 { 5021 const char *fmt; 5022 int c; 5023 5024 if (fmt1 == NULL) 5025 fmt = fmt2; 5026 else 5027 /* XXX bogus */ 5028 fmt = strncmp(name, "lib", 3) == 0 ? fmt1 : fmt2; 5029 5030 while ((c = *fmt++) != '\0') { 5031 switch (c) { 5032 default: 5033 rtld_putchar(c); 5034 continue; 5035 case '\\': 5036 switch (c = *fmt) { 5037 case '\0': 5038 continue; 5039 case 'n': 5040 rtld_putchar('\n'); 5041 break; 5042 case 't': 5043 rtld_putchar('\t'); 5044 break; 5045 } 5046 break; 5047 case '%': 5048 switch (c = *fmt) { 5049 case '\0': 5050 continue; 5051 case '%': 5052 default: 5053 rtld_putchar(c); 5054 break; 5055 case 'A': 5056 rtld_putstr(main_local); 5057 break; 5058 case 'a': 5059 rtld_putstr(obj_main->path); 5060 break; 5061 case 'o': 5062 rtld_putstr(name); 5063 break; 5064 case 'p': 5065 rtld_putstr(path); 5066 break; 5067 case 'x': 5068 rtld_printf("%p", obj != NULL ? 5069 obj->mapbase : NULL); 5070 break; 5071 } 5072 break; 5073 } 5074 ++fmt; 5075 } 5076 } 5077 5078 static void 5079 trace_loaded_objects(Obj_Entry *obj, bool show_preload) 5080 { 5081 const char *fmt1, *fmt2, *main_local; 5082 const char *name, *path; 5083 bool first_spurious, list_containers; 5084 5085 trace_calc_fmts(&main_local, &fmt1, &fmt2); 5086 list_containers = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_ALL) != NULL; 5087 5088 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 5089 Needed_Entry *needed; 5090 5091 if (obj->marker) 5092 continue; 5093 if (list_containers && obj->needed != NULL) 5094 rtld_printf("%s:\n", obj->path); 5095 for (needed = obj->needed; needed; needed = needed->next) { 5096 if (needed->obj != NULL) { 5097 if (needed->obj->traced && !list_containers) 5098 continue; 5099 needed->obj->traced = true; 5100 path = needed->obj->path; 5101 } else 5102 path = "not found"; 5103 5104 name = obj->strtab + needed->name; 5105 trace_print_obj(needed->obj, name, path, main_local, 5106 fmt1, fmt2); 5107 } 5108 } 5109 5110 if (show_preload) { 5111 if (ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT2) == NULL) 5112 fmt2 = "\t%p (%x)\n"; 5113 first_spurious = true; 5114 5115 TAILQ_FOREACH(obj, &obj_list, next) { 5116 if (obj->marker || obj == obj_main || obj->traced) 5117 continue; 5118 5119 if (list_containers && first_spurious) { 5120 rtld_printf("[preloaded]\n"); 5121 first_spurious = false; 5122 } 5123 5124 Name_Entry *fname = STAILQ_FIRST(&obj->names); 5125 name = fname == NULL ? "<unknown>" : fname->name; 5126 trace_print_obj(obj, name, obj->path, main_local, 5127 NULL, fmt2); 5128 } 5129 } 5130 } 5131 5132 /* 5133 * Unload a dlopened object and its dependencies from memory and from 5134 * our data structures. It is assumed that the DAG rooted in the 5135 * object has already been unreferenced, and that the object has a 5136 * reference count of 0. 5137 */ 5138 static void 5139 unload_object(Obj_Entry *root, RtldLockState *lockstate) 5140 { 5141 Obj_Entry marker, *obj, *next; 5142 5143 assert(root->refcount == 0); 5144 5145 /* 5146 * Pass over the DAG removing unreferenced objects from 5147 * appropriate lists. 5148 */ 5149 unlink_object(root); 5150 5151 /* Unmap all objects that are no longer referenced. */ 5152 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) { 5153 next = TAILQ_NEXT(obj, next); 5154 if (obj->marker || obj->refcount != 0) 5155 continue; 5156 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 5157 obj->mapsize, 0, obj->path); 5158 dbg("unloading \"%s\"", obj->path); 5159 /* 5160 * Unlink the object now to prevent new references from 5161 * being acquired while the bind lock is dropped in 5162 * recursive dlclose() invocations. 5163 */ 5164 TAILQ_REMOVE(&obj_list, obj, next); 5165 obj_count--; 5166 5167 if (obj->filtees_loaded) { 5168 if (next != NULL) { 5169 init_marker(&marker); 5170 TAILQ_INSERT_BEFORE(next, &marker, next); 5171 unload_filtees(obj, lockstate); 5172 next = TAILQ_NEXT(&marker, next); 5173 TAILQ_REMOVE(&obj_list, &marker, next); 5174 } else 5175 unload_filtees(obj, lockstate); 5176 } 5177 release_object(obj); 5178 } 5179 } 5180 5181 static void 5182 unlink_object(Obj_Entry *root) 5183 { 5184 Objlist_Entry *elm; 5185 5186 if (root->refcount == 0) { 5187 /* Remove the object from the RTLD_GLOBAL list. */ 5188 objlist_remove(&list_global, root); 5189 5190 /* Remove the object from all objects' DAG lists. */ 5191 STAILQ_FOREACH(elm, &root->dagmembers, link) { 5192 objlist_remove(&elm->obj->dldags, root); 5193 if (elm->obj != root) 5194 unlink_object(elm->obj); 5195 } 5196 } 5197 } 5198 5199 static void 5200 ref_dag(Obj_Entry *root) 5201 { 5202 Objlist_Entry *elm; 5203 5204 assert(root->dag_inited); 5205 STAILQ_FOREACH(elm, &root->dagmembers, link) 5206 elm->obj->refcount++; 5207 } 5208 5209 static void 5210 unref_dag(Obj_Entry *root) 5211 { 5212 Objlist_Entry *elm; 5213 5214 assert(root->dag_inited); 5215 STAILQ_FOREACH(elm, &root->dagmembers, link) 5216 elm->obj->refcount--; 5217 } 5218 5219 /* 5220 * Common code for MD __tls_get_addr(). 5221 */ 5222 static void * 5223 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset, bool locked) 5224 { 5225 Elf_Addr *newdtv, *dtv; 5226 RtldLockState lockstate; 5227 int to_copy; 5228 5229 dtv = *dtvp; 5230 /* Check dtv generation in case new modules have arrived */ 5231 if (dtv[0] != tls_dtv_generation) { 5232 if (!locked) 5233 wlock_acquire(rtld_bind_lock, &lockstate); 5234 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5235 to_copy = dtv[1]; 5236 if (to_copy > tls_max_index) 5237 to_copy = tls_max_index; 5238 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 5239 newdtv[0] = tls_dtv_generation; 5240 newdtv[1] = tls_max_index; 5241 free(dtv); 5242 if (!locked) 5243 lock_release(rtld_bind_lock, &lockstate); 5244 dtv = *dtvp = newdtv; 5245 } 5246 5247 /* Dynamically allocate module TLS if necessary */ 5248 if (dtv[index + 1] == 0) { 5249 /* Signal safe, wlock will block out signals. */ 5250 if (!locked) 5251 wlock_acquire(rtld_bind_lock, &lockstate); 5252 if (!dtv[index + 1]) 5253 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 5254 if (!locked) 5255 lock_release(rtld_bind_lock, &lockstate); 5256 } 5257 return ((void *)(dtv[index + 1] + offset)); 5258 } 5259 5260 void * 5261 tls_get_addr_common(uintptr_t **dtvp, int index, size_t offset) 5262 { 5263 uintptr_t *dtv; 5264 5265 dtv = *dtvp; 5266 /* Check dtv generation in case new modules have arrived */ 5267 if (__predict_true(dtv[0] == tls_dtv_generation && 5268 dtv[index + 1] != 0)) 5269 return ((void *)(dtv[index + 1] + offset)); 5270 return (tls_get_addr_slow(dtvp, index, offset, false)); 5271 } 5272 5273 #ifdef TLS_VARIANT_I 5274 5275 /* 5276 * Return pointer to allocated TLS block 5277 */ 5278 static void * 5279 get_tls_block_ptr(void *tcb, size_t tcbsize) 5280 { 5281 size_t extra_size, post_size, pre_size, tls_block_size; 5282 size_t tls_init_align; 5283 5284 tls_init_align = MAX(obj_main->tlsalign, 1); 5285 5286 /* Compute fragments sizes. */ 5287 extra_size = tcbsize - TLS_TCB_SIZE; 5288 post_size = calculate_tls_post_size(tls_init_align); 5289 tls_block_size = tcbsize + post_size; 5290 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 5291 5292 return ((char *)tcb - pre_size - extra_size); 5293 } 5294 5295 /* 5296 * Allocate Static TLS using the Variant I method. 5297 * 5298 * For details on the layout, see lib/libc/gen/tls.c. 5299 * 5300 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as 5301 * it is based on tls_last_offset, and TLS offsets here are really TCB 5302 * offsets, whereas libc's tls_static_space is just the executable's static 5303 * TLS segment. 5304 */ 5305 void * 5306 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 5307 { 5308 Obj_Entry *obj; 5309 char *tls_block; 5310 Elf_Addr *dtv, **tcb; 5311 Elf_Addr addr; 5312 Elf_Addr i; 5313 size_t extra_size, maxalign, post_size, pre_size, tls_block_size; 5314 size_t tls_init_align, tls_init_offset; 5315 5316 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 5317 return (oldtcb); 5318 5319 assert(tcbsize >= TLS_TCB_SIZE); 5320 maxalign = MAX(tcbalign, tls_static_max_align); 5321 tls_init_align = MAX(obj_main->tlsalign, 1); 5322 5323 /* Compute fragmets sizes. */ 5324 extra_size = tcbsize - TLS_TCB_SIZE; 5325 post_size = calculate_tls_post_size(tls_init_align); 5326 tls_block_size = tcbsize + post_size; 5327 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 5328 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size; 5329 5330 /* Allocate whole TLS block */ 5331 tls_block = xmalloc_aligned(tls_block_size, maxalign, 0); 5332 tcb = (Elf_Addr **)(tls_block + pre_size + extra_size); 5333 5334 if (oldtcb != NULL) { 5335 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize), 5336 tls_static_space); 5337 free(get_tls_block_ptr(oldtcb, tcbsize)); 5338 5339 /* Adjust the DTV. */ 5340 dtv = tcb[0]; 5341 for (i = 0; i < dtv[1]; i++) { 5342 if (dtv[i+2] >= (Elf_Addr)oldtcb && 5343 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 5344 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tcb; 5345 } 5346 } 5347 } else { 5348 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5349 tcb[0] = dtv; 5350 dtv[0] = tls_dtv_generation; 5351 dtv[1] = tls_max_index; 5352 5353 for (obj = globallist_curr(objs); obj != NULL; 5354 obj = globallist_next(obj)) { 5355 if (obj->tlsoffset == 0) 5356 continue; 5357 tls_init_offset = obj->tlspoffset & (obj->tlsalign - 1); 5358 addr = (Elf_Addr)tcb + obj->tlsoffset; 5359 if (tls_init_offset > 0) 5360 memset((void *)addr, 0, tls_init_offset); 5361 if (obj->tlsinitsize > 0) { 5362 memcpy((void *)(addr + tls_init_offset), obj->tlsinit, 5363 obj->tlsinitsize); 5364 } 5365 if (obj->tlssize > obj->tlsinitsize) { 5366 memset((void *)(addr + tls_init_offset + obj->tlsinitsize), 5367 0, obj->tlssize - obj->tlsinitsize - tls_init_offset); 5368 } 5369 dtv[obj->tlsindex + 1] = addr; 5370 } 5371 } 5372 5373 return (tcb); 5374 } 5375 5376 void 5377 free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused) 5378 { 5379 Elf_Addr *dtv; 5380 Elf_Addr tlsstart, tlsend; 5381 size_t post_size; 5382 size_t dtvsize, i, tls_init_align __unused; 5383 5384 assert(tcbsize >= TLS_TCB_SIZE); 5385 tls_init_align = MAX(obj_main->tlsalign, 1); 5386 5387 /* Compute fragments sizes. */ 5388 post_size = calculate_tls_post_size(tls_init_align); 5389 5390 tlsstart = (Elf_Addr)tcb + TLS_TCB_SIZE + post_size; 5391 tlsend = (Elf_Addr)tcb + tls_static_space; 5392 5393 dtv = *(Elf_Addr **)tcb; 5394 dtvsize = dtv[1]; 5395 for (i = 0; i < dtvsize; i++) { 5396 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 5397 free((void*)dtv[i+2]); 5398 } 5399 } 5400 free(dtv); 5401 free(get_tls_block_ptr(tcb, tcbsize)); 5402 } 5403 5404 #endif /* TLS_VARIANT_I */ 5405 5406 #ifdef TLS_VARIANT_II 5407 5408 /* 5409 * Allocate Static TLS using the Variant II method. 5410 */ 5411 void * 5412 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 5413 { 5414 Obj_Entry *obj; 5415 size_t size, ralign; 5416 char *tls; 5417 Elf_Addr *dtv, *olddtv; 5418 Elf_Addr segbase, oldsegbase, addr; 5419 size_t i; 5420 5421 ralign = tcbalign; 5422 if (tls_static_max_align > ralign) 5423 ralign = tls_static_max_align; 5424 size = roundup(tls_static_space, ralign) + roundup(tcbsize, ralign); 5425 5426 assert(tcbsize >= 2*sizeof(Elf_Addr)); 5427 tls = xmalloc_aligned(size, ralign, 0 /* XXX */); 5428 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5429 5430 segbase = (Elf_Addr)(tls + roundup(tls_static_space, ralign)); 5431 ((Elf_Addr *)segbase)[0] = segbase; 5432 ((Elf_Addr *)segbase)[1] = (Elf_Addr) dtv; 5433 5434 dtv[0] = tls_dtv_generation; 5435 dtv[1] = tls_max_index; 5436 5437 if (oldtls) { 5438 /* 5439 * Copy the static TLS block over whole. 5440 */ 5441 oldsegbase = (Elf_Addr) oldtls; 5442 memcpy((void *)(segbase - tls_static_space), 5443 (const void *)(oldsegbase - tls_static_space), 5444 tls_static_space); 5445 5446 /* 5447 * If any dynamic TLS blocks have been created tls_get_addr(), 5448 * move them over. 5449 */ 5450 olddtv = ((Elf_Addr **)oldsegbase)[1]; 5451 for (i = 0; i < olddtv[1]; i++) { 5452 if (olddtv[i + 2] < oldsegbase - size || 5453 olddtv[i + 2] > oldsegbase) { 5454 dtv[i + 2] = olddtv[i + 2]; 5455 olddtv[i + 2] = 0; 5456 } 5457 } 5458 5459 /* 5460 * We assume that this block was the one we created with 5461 * allocate_initial_tls(). 5462 */ 5463 free_tls(oldtls, 2 * sizeof(Elf_Addr), sizeof(Elf_Addr)); 5464 } else { 5465 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 5466 if (obj->marker || obj->tlsoffset == 0) 5467 continue; 5468 addr = segbase - obj->tlsoffset; 5469 memset((void *)(addr + obj->tlsinitsize), 5470 0, obj->tlssize - obj->tlsinitsize); 5471 if (obj->tlsinit) { 5472 memcpy((void *)addr, obj->tlsinit, obj->tlsinitsize); 5473 obj->static_tls_copied = true; 5474 } 5475 dtv[obj->tlsindex + 1] = addr; 5476 } 5477 } 5478 5479 return ((void *)segbase); 5480 } 5481 5482 void 5483 free_tls(void *tls, size_t tcbsize __unused, size_t tcbalign) 5484 { 5485 Elf_Addr* dtv; 5486 size_t size, ralign; 5487 int dtvsize, i; 5488 Elf_Addr tlsstart, tlsend; 5489 5490 /* 5491 * Figure out the size of the initial TLS block so that we can 5492 * find stuff which ___tls_get_addr() allocated dynamically. 5493 */ 5494 ralign = tcbalign; 5495 if (tls_static_max_align > ralign) 5496 ralign = tls_static_max_align; 5497 size = roundup(tls_static_space, ralign); 5498 5499 dtv = ((Elf_Addr **)tls)[1]; 5500 dtvsize = dtv[1]; 5501 tlsend = (Elf_Addr)tls; 5502 tlsstart = tlsend - size; 5503 for (i = 0; i < dtvsize; i++) { 5504 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || 5505 dtv[i + 2] > tlsend)) { 5506 free((void *)dtv[i + 2]); 5507 } 5508 } 5509 5510 free((void *)tlsstart); 5511 free((void *)dtv); 5512 } 5513 5514 #endif /* TLS_VARIANT_II */ 5515 5516 /* 5517 * Allocate TLS block for module with given index. 5518 */ 5519 void * 5520 allocate_module_tls(int index) 5521 { 5522 Obj_Entry *obj; 5523 char *p; 5524 5525 TAILQ_FOREACH(obj, &obj_list, next) { 5526 if (obj->marker) 5527 continue; 5528 if (obj->tlsindex == index) 5529 break; 5530 } 5531 if (obj == NULL) { 5532 _rtld_error("Can't find module with TLS index %d", index); 5533 rtld_die(); 5534 } 5535 5536 if (obj->tls_static) { 5537 #ifdef TLS_VARIANT_I 5538 p = (char *)_tcb_get() + obj->tlsoffset + TLS_TCB_SIZE; 5539 #else 5540 p = (char *)_tcb_get() - obj->tlsoffset; 5541 #endif 5542 return (p); 5543 } 5544 5545 obj->tls_dynamic = true; 5546 5547 p = xmalloc_aligned(obj->tlssize, obj->tlsalign, obj->tlspoffset); 5548 memcpy(p, obj->tlsinit, obj->tlsinitsize); 5549 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 5550 return (p); 5551 } 5552 5553 bool 5554 allocate_tls_offset(Obj_Entry *obj) 5555 { 5556 size_t off; 5557 5558 if (obj->tls_dynamic) 5559 return (false); 5560 5561 if (obj->tls_static) 5562 return (true); 5563 5564 if (obj->tlssize == 0) { 5565 obj->tls_static = true; 5566 return (true); 5567 } 5568 5569 if (tls_last_offset == 0) 5570 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign, 5571 obj->tlspoffset); 5572 else 5573 off = calculate_tls_offset(tls_last_offset, tls_last_size, 5574 obj->tlssize, obj->tlsalign, obj->tlspoffset); 5575 5576 obj->tlsoffset = off; 5577 #ifdef TLS_VARIANT_I 5578 off += obj->tlssize; 5579 #endif 5580 5581 /* 5582 * If we have already fixed the size of the static TLS block, we 5583 * must stay within that size. When allocating the static TLS, we 5584 * leave a small amount of space spare to be used for dynamically 5585 * loading modules which use static TLS. 5586 */ 5587 if (tls_static_space != 0) { 5588 if (off > tls_static_space) 5589 return (false); 5590 } else if (obj->tlsalign > tls_static_max_align) { 5591 tls_static_max_align = obj->tlsalign; 5592 } 5593 5594 tls_last_offset = off; 5595 tls_last_size = obj->tlssize; 5596 obj->tls_static = true; 5597 5598 return (true); 5599 } 5600 5601 void 5602 free_tls_offset(Obj_Entry *obj) 5603 { 5604 5605 /* 5606 * If we were the last thing to allocate out of the static TLS 5607 * block, we give our space back to the 'allocator'. This is a 5608 * simplistic workaround to allow libGL.so.1 to be loaded and 5609 * unloaded multiple times. 5610 */ 5611 size_t off = obj->tlsoffset; 5612 #ifdef TLS_VARIANT_I 5613 off += obj->tlssize; 5614 #endif 5615 if (off == tls_last_offset) { 5616 tls_last_offset -= obj->tlssize; 5617 tls_last_size = 0; 5618 } 5619 } 5620 5621 void * 5622 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 5623 { 5624 void *ret; 5625 RtldLockState lockstate; 5626 5627 wlock_acquire(rtld_bind_lock, &lockstate); 5628 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 5629 tcbsize, tcbalign); 5630 lock_release(rtld_bind_lock, &lockstate); 5631 return (ret); 5632 } 5633 5634 void 5635 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 5636 { 5637 RtldLockState lockstate; 5638 5639 wlock_acquire(rtld_bind_lock, &lockstate); 5640 free_tls(tcb, tcbsize, tcbalign); 5641 lock_release(rtld_bind_lock, &lockstate); 5642 } 5643 5644 static void 5645 object_add_name(Obj_Entry *obj, const char *name) 5646 { 5647 Name_Entry *entry; 5648 size_t len; 5649 5650 len = strlen(name); 5651 entry = malloc(sizeof(Name_Entry) + len); 5652 5653 if (entry != NULL) { 5654 strcpy(entry->name, name); 5655 STAILQ_INSERT_TAIL(&obj->names, entry, link); 5656 } 5657 } 5658 5659 static int 5660 object_match_name(const Obj_Entry *obj, const char *name) 5661 { 5662 Name_Entry *entry; 5663 5664 STAILQ_FOREACH(entry, &obj->names, link) { 5665 if (strcmp(name, entry->name) == 0) 5666 return (1); 5667 } 5668 return (0); 5669 } 5670 5671 static Obj_Entry * 5672 locate_dependency(const Obj_Entry *obj, const char *name) 5673 { 5674 const Objlist_Entry *entry; 5675 const Needed_Entry *needed; 5676 5677 STAILQ_FOREACH(entry, &list_main, link) { 5678 if (object_match_name(entry->obj, name)) 5679 return (entry->obj); 5680 } 5681 5682 for (needed = obj->needed; needed != NULL; needed = needed->next) { 5683 if (strcmp(obj->strtab + needed->name, name) == 0 || 5684 (needed->obj != NULL && object_match_name(needed->obj, name))) { 5685 /* 5686 * If there is DT_NEEDED for the name we are looking for, 5687 * we are all set. Note that object might not be found if 5688 * dependency was not loaded yet, so the function can 5689 * return NULL here. This is expected and handled 5690 * properly by the caller. 5691 */ 5692 return (needed->obj); 5693 } 5694 } 5695 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 5696 obj->path, name); 5697 rtld_die(); 5698 } 5699 5700 static int 5701 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 5702 const Elf_Vernaux *vna) 5703 { 5704 const Elf_Verdef *vd; 5705 const char *vername; 5706 5707 vername = refobj->strtab + vna->vna_name; 5708 vd = depobj->verdef; 5709 if (vd == NULL) { 5710 _rtld_error("%s: version %s required by %s not defined", 5711 depobj->path, vername, refobj->path); 5712 return (-1); 5713 } 5714 for (;;) { 5715 if (vd->vd_version != VER_DEF_CURRENT) { 5716 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5717 depobj->path, vd->vd_version); 5718 return (-1); 5719 } 5720 if (vna->vna_hash == vd->vd_hash) { 5721 const Elf_Verdaux *aux = (const Elf_Verdaux *) 5722 ((const char *)vd + vd->vd_aux); 5723 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 5724 return (0); 5725 } 5726 if (vd->vd_next == 0) 5727 break; 5728 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5729 } 5730 if (vna->vna_flags & VER_FLG_WEAK) 5731 return (0); 5732 _rtld_error("%s: version %s required by %s not found", 5733 depobj->path, vername, refobj->path); 5734 return (-1); 5735 } 5736 5737 static int 5738 rtld_verify_object_versions(Obj_Entry *obj) 5739 { 5740 const Elf_Verneed *vn; 5741 const Elf_Verdef *vd; 5742 const Elf_Verdaux *vda; 5743 const Elf_Vernaux *vna; 5744 const Obj_Entry *depobj; 5745 int maxvernum, vernum; 5746 5747 if (obj->ver_checked) 5748 return (0); 5749 obj->ver_checked = true; 5750 5751 maxvernum = 0; 5752 /* 5753 * Walk over defined and required version records and figure out 5754 * max index used by any of them. Do very basic sanity checking 5755 * while there. 5756 */ 5757 vn = obj->verneed; 5758 while (vn != NULL) { 5759 if (vn->vn_version != VER_NEED_CURRENT) { 5760 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 5761 obj->path, vn->vn_version); 5762 return (-1); 5763 } 5764 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5765 for (;;) { 5766 vernum = VER_NEED_IDX(vna->vna_other); 5767 if (vernum > maxvernum) 5768 maxvernum = vernum; 5769 if (vna->vna_next == 0) 5770 break; 5771 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5772 } 5773 if (vn->vn_next == 0) 5774 break; 5775 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5776 } 5777 5778 vd = obj->verdef; 5779 while (vd != NULL) { 5780 if (vd->vd_version != VER_DEF_CURRENT) { 5781 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5782 obj->path, vd->vd_version); 5783 return (-1); 5784 } 5785 vernum = VER_DEF_IDX(vd->vd_ndx); 5786 if (vernum > maxvernum) 5787 maxvernum = vernum; 5788 if (vd->vd_next == 0) 5789 break; 5790 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5791 } 5792 5793 if (maxvernum == 0) 5794 return (0); 5795 5796 /* 5797 * Store version information in array indexable by version index. 5798 * Verify that object version requirements are satisfied along the 5799 * way. 5800 */ 5801 obj->vernum = maxvernum + 1; 5802 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 5803 5804 vd = obj->verdef; 5805 while (vd != NULL) { 5806 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 5807 vernum = VER_DEF_IDX(vd->vd_ndx); 5808 assert(vernum <= maxvernum); 5809 vda = (const Elf_Verdaux *)((const char *)vd + vd->vd_aux); 5810 obj->vertab[vernum].hash = vd->vd_hash; 5811 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 5812 obj->vertab[vernum].file = NULL; 5813 obj->vertab[vernum].flags = 0; 5814 } 5815 if (vd->vd_next == 0) 5816 break; 5817 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5818 } 5819 5820 vn = obj->verneed; 5821 while (vn != NULL) { 5822 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 5823 if (depobj == NULL) 5824 return (-1); 5825 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5826 for (;;) { 5827 if (check_object_provided_version(obj, depobj, vna)) 5828 return (-1); 5829 vernum = VER_NEED_IDX(vna->vna_other); 5830 assert(vernum <= maxvernum); 5831 obj->vertab[vernum].hash = vna->vna_hash; 5832 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 5833 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 5834 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 5835 VER_INFO_HIDDEN : 0; 5836 if (vna->vna_next == 0) 5837 break; 5838 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5839 } 5840 if (vn->vn_next == 0) 5841 break; 5842 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5843 } 5844 return (0); 5845 } 5846 5847 static int 5848 rtld_verify_versions(const Objlist *objlist) 5849 { 5850 Objlist_Entry *entry; 5851 int rc; 5852 5853 rc = 0; 5854 STAILQ_FOREACH(entry, objlist, link) { 5855 /* 5856 * Skip dummy objects or objects that have their version requirements 5857 * already checked. 5858 */ 5859 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 5860 continue; 5861 if (rtld_verify_object_versions(entry->obj) == -1) { 5862 rc = -1; 5863 if (ld_tracing == NULL) 5864 break; 5865 } 5866 } 5867 if (rc == 0 || ld_tracing != NULL) 5868 rc = rtld_verify_object_versions(&obj_rtld); 5869 return (rc); 5870 } 5871 5872 const Ver_Entry * 5873 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 5874 { 5875 Elf_Versym vernum; 5876 5877 if (obj->vertab) { 5878 vernum = VER_NDX(obj->versyms[symnum]); 5879 if (vernum >= obj->vernum) { 5880 _rtld_error("%s: symbol %s has wrong verneed value %d", 5881 obj->path, obj->strtab + symnum, vernum); 5882 } else if (obj->vertab[vernum].hash != 0) { 5883 return (&obj->vertab[vernum]); 5884 } 5885 } 5886 return (NULL); 5887 } 5888 5889 int 5890 _rtld_get_stack_prot(void) 5891 { 5892 5893 return (stack_prot); 5894 } 5895 5896 int 5897 _rtld_is_dlopened(void *arg) 5898 { 5899 Obj_Entry *obj; 5900 RtldLockState lockstate; 5901 int res; 5902 5903 rlock_acquire(rtld_bind_lock, &lockstate); 5904 obj = dlcheck(arg); 5905 if (obj == NULL) 5906 obj = obj_from_addr(arg); 5907 if (obj == NULL) { 5908 _rtld_error("No shared object contains address"); 5909 lock_release(rtld_bind_lock, &lockstate); 5910 return (-1); 5911 } 5912 res = obj->dlopened ? 1 : 0; 5913 lock_release(rtld_bind_lock, &lockstate); 5914 return (res); 5915 } 5916 5917 static int 5918 obj_remap_relro(Obj_Entry *obj, int prot) 5919 { 5920 5921 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size, 5922 prot) == -1) { 5923 _rtld_error("%s: Cannot set relro protection to %#x: %s", 5924 obj->path, prot, rtld_strerror(errno)); 5925 return (-1); 5926 } 5927 return (0); 5928 } 5929 5930 static int 5931 obj_disable_relro(Obj_Entry *obj) 5932 { 5933 5934 return (obj_remap_relro(obj, PROT_READ | PROT_WRITE)); 5935 } 5936 5937 static int 5938 obj_enforce_relro(Obj_Entry *obj) 5939 { 5940 5941 return (obj_remap_relro(obj, PROT_READ)); 5942 } 5943 5944 static void 5945 map_stacks_exec(RtldLockState *lockstate) 5946 { 5947 void (*thr_map_stacks_exec)(void); 5948 5949 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5950 return; 5951 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5952 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5953 if (thr_map_stacks_exec != NULL) { 5954 stack_prot |= PROT_EXEC; 5955 thr_map_stacks_exec(); 5956 } 5957 } 5958 5959 static void 5960 distribute_static_tls(Objlist *list, RtldLockState *lockstate) 5961 { 5962 Objlist_Entry *elm; 5963 Obj_Entry *obj; 5964 void (*distrib)(size_t, void *, size_t, size_t); 5965 5966 distrib = (void (*)(size_t, void *, size_t, size_t))(uintptr_t) 5967 get_program_var_addr("__pthread_distribute_static_tls", lockstate); 5968 if (distrib == NULL) 5969 return; 5970 STAILQ_FOREACH(elm, list, link) { 5971 obj = elm->obj; 5972 if (obj->marker || !obj->tls_static || obj->static_tls_copied) 5973 continue; 5974 lock_release(rtld_bind_lock, lockstate); 5975 distrib(obj->tlsoffset, obj->tlsinit, obj->tlsinitsize, 5976 obj->tlssize); 5977 wlock_acquire(rtld_bind_lock, lockstate); 5978 obj->static_tls_copied = true; 5979 } 5980 } 5981 5982 void 5983 symlook_init(SymLook *dst, const char *name) 5984 { 5985 5986 bzero(dst, sizeof(*dst)); 5987 dst->name = name; 5988 dst->hash = elf_hash(name); 5989 dst->hash_gnu = gnu_hash(name); 5990 } 5991 5992 static void 5993 symlook_init_from_req(SymLook *dst, const SymLook *src) 5994 { 5995 5996 dst->name = src->name; 5997 dst->hash = src->hash; 5998 dst->hash_gnu = src->hash_gnu; 5999 dst->ventry = src->ventry; 6000 dst->flags = src->flags; 6001 dst->defobj_out = NULL; 6002 dst->sym_out = NULL; 6003 dst->lockstate = src->lockstate; 6004 } 6005 6006 static int 6007 open_binary_fd(const char *argv0, bool search_in_path, 6008 const char **binpath_res) 6009 { 6010 char *binpath, *pathenv, *pe, *res1; 6011 const char *res; 6012 int fd; 6013 6014 binpath = NULL; 6015 res = NULL; 6016 if (search_in_path && strchr(argv0, '/') == NULL) { 6017 binpath = xmalloc(PATH_MAX); 6018 pathenv = getenv("PATH"); 6019 if (pathenv == NULL) { 6020 _rtld_error("-p and no PATH environment variable"); 6021 rtld_die(); 6022 } 6023 pathenv = strdup(pathenv); 6024 if (pathenv == NULL) { 6025 _rtld_error("Cannot allocate memory"); 6026 rtld_die(); 6027 } 6028 fd = -1; 6029 errno = ENOENT; 6030 while ((pe = strsep(&pathenv, ":")) != NULL) { 6031 if (strlcpy(binpath, pe, PATH_MAX) >= PATH_MAX) 6032 continue; 6033 if (binpath[0] != '\0' && 6034 strlcat(binpath, "/", PATH_MAX) >= PATH_MAX) 6035 continue; 6036 if (strlcat(binpath, argv0, PATH_MAX) >= PATH_MAX) 6037 continue; 6038 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY); 6039 if (fd != -1 || errno != ENOENT) { 6040 res = binpath; 6041 break; 6042 } 6043 } 6044 free(pathenv); 6045 } else { 6046 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY); 6047 res = argv0; 6048 } 6049 6050 if (fd == -1) { 6051 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno)); 6052 rtld_die(); 6053 } 6054 if (res != NULL && res[0] != '/') { 6055 res1 = xmalloc(PATH_MAX); 6056 if (realpath(res, res1) != NULL) { 6057 if (res != argv0) 6058 free(__DECONST(char *, res)); 6059 res = res1; 6060 } else { 6061 free(res1); 6062 } 6063 } 6064 *binpath_res = res; 6065 return (fd); 6066 } 6067 6068 /* 6069 * Parse a set of command-line arguments. 6070 */ 6071 static int 6072 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp, 6073 const char **argv0, bool *dir_ignore) 6074 { 6075 const char *arg; 6076 char machine[64]; 6077 size_t sz; 6078 int arglen, fd, i, j, mib[2]; 6079 char opt; 6080 bool seen_b, seen_f; 6081 6082 dbg("Parsing command-line arguments"); 6083 *use_pathp = false; 6084 *fdp = -1; 6085 *dir_ignore = false; 6086 seen_b = seen_f = false; 6087 6088 for (i = 1; i < argc; i++ ) { 6089 arg = argv[i]; 6090 dbg("argv[%d]: '%s'", i, arg); 6091 6092 /* 6093 * rtld arguments end with an explicit "--" or with the first 6094 * non-prefixed argument. 6095 */ 6096 if (strcmp(arg, "--") == 0) { 6097 i++; 6098 break; 6099 } 6100 if (arg[0] != '-') 6101 break; 6102 6103 /* 6104 * All other arguments are single-character options that can 6105 * be combined, so we need to search through `arg` for them. 6106 */ 6107 arglen = strlen(arg); 6108 for (j = 1; j < arglen; j++) { 6109 opt = arg[j]; 6110 if (opt == 'h') { 6111 print_usage(argv[0]); 6112 _exit(0); 6113 } else if (opt == 'b') { 6114 if (seen_f) { 6115 _rtld_error("Both -b and -f specified"); 6116 rtld_die(); 6117 } 6118 if (j != arglen - 1) { 6119 _rtld_error("Invalid options: %s", arg); 6120 rtld_die(); 6121 } 6122 i++; 6123 *argv0 = argv[i]; 6124 seen_b = true; 6125 break; 6126 } else if (opt == 'd') { 6127 *dir_ignore = true; 6128 } else if (opt == 'f') { 6129 if (seen_b) { 6130 _rtld_error("Both -b and -f specified"); 6131 rtld_die(); 6132 } 6133 6134 /* 6135 * -f XX can be used to specify a 6136 * descriptor for the binary named at 6137 * the command line (i.e., the later 6138 * argument will specify the process 6139 * name but the descriptor is what 6140 * will actually be executed). 6141 * 6142 * -f must be the last option in the 6143 * group, e.g., -abcf <fd>. 6144 */ 6145 if (j != arglen - 1) { 6146 _rtld_error("Invalid options: %s", arg); 6147 rtld_die(); 6148 } 6149 i++; 6150 fd = parse_integer(argv[i]); 6151 if (fd == -1) { 6152 _rtld_error( 6153 "Invalid file descriptor: '%s'", 6154 argv[i]); 6155 rtld_die(); 6156 } 6157 *fdp = fd; 6158 seen_f = true; 6159 break; 6160 } else if (opt == 'o') { 6161 struct ld_env_var_desc *l; 6162 char *n, *v; 6163 u_int ll; 6164 6165 if (j != arglen - 1) { 6166 _rtld_error("Invalid options: %s", arg); 6167 rtld_die(); 6168 } 6169 i++; 6170 n = argv[i]; 6171 v = strchr(n, '='); 6172 if (v == NULL) { 6173 _rtld_error("No '=' in -o parameter"); 6174 rtld_die(); 6175 } 6176 for (ll = 0; ll < nitems(ld_env_vars); ll++) { 6177 l = &ld_env_vars[ll]; 6178 if (v - n == (ptrdiff_t)strlen(l->n) && 6179 strncmp(n, l->n, v - n) == 0) { 6180 l->val = v + 1; 6181 break; 6182 } 6183 } 6184 if (ll == nitems(ld_env_vars)) { 6185 _rtld_error("Unknown LD_ option %s", 6186 n); 6187 rtld_die(); 6188 } 6189 } else if (opt == 'p') { 6190 *use_pathp = true; 6191 } else if (opt == 'u') { 6192 u_int ll; 6193 6194 for (ll = 0; ll < nitems(ld_env_vars); ll++) 6195 ld_env_vars[ll].val = NULL; 6196 } else if (opt == 'v') { 6197 machine[0] = '\0'; 6198 mib[0] = CTL_HW; 6199 mib[1] = HW_MACHINE; 6200 sz = sizeof(machine); 6201 sysctl(mib, nitems(mib), machine, &sz, NULL, 0); 6202 ld_elf_hints_path = ld_get_env_var( 6203 LD_ELF_HINTS_PATH); 6204 set_ld_elf_hints_path(); 6205 rtld_printf( 6206 "FreeBSD ld-elf.so.1 %s\n" 6207 "FreeBSD_version %d\n" 6208 "Default lib path %s\n" 6209 "Hints lib path %s\n" 6210 "Env prefix %s\n" 6211 "Default hint file %s\n" 6212 "Hint file %s\n" 6213 "libmap file %s\n" 6214 "Optional static TLS size %zd bytes\n", 6215 machine, 6216 __FreeBSD_version, ld_standard_library_path, 6217 gethints(false), 6218 ld_env_prefix, ld_elf_hints_default, 6219 ld_elf_hints_path, 6220 ld_path_libmap_conf, 6221 ld_static_tls_extra); 6222 _exit(0); 6223 } else { 6224 _rtld_error("Invalid argument: '%s'", arg); 6225 print_usage(argv[0]); 6226 rtld_die(); 6227 } 6228 } 6229 } 6230 6231 if (!seen_b) 6232 *argv0 = argv[i]; 6233 return (i); 6234 } 6235 6236 /* 6237 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 6238 */ 6239 static int 6240 parse_integer(const char *str) 6241 { 6242 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 6243 const char *orig; 6244 int n; 6245 char c; 6246 6247 orig = str; 6248 n = 0; 6249 for (c = *str; c != '\0'; c = *++str) { 6250 if (c < '0' || c > '9') 6251 return (-1); 6252 6253 n *= RADIX; 6254 n += c - '0'; 6255 } 6256 6257 /* Make sure we actually parsed something. */ 6258 if (str == orig) 6259 return (-1); 6260 return (n); 6261 } 6262 6263 static void 6264 print_usage(const char *argv0) 6265 { 6266 6267 rtld_printf( 6268 "Usage: %s [-h] [-b <exe>] [-d] [-f <FD>] [-p] [--] <binary> [<args>]\n" 6269 "\n" 6270 "Options:\n" 6271 " -h Display this help message\n" 6272 " -b <exe> Execute <exe> instead of <binary>, arg0 is <binary>\n" 6273 " -d Ignore lack of exec permissions for the binary\n" 6274 " -f <FD> Execute <FD> instead of searching for <binary>\n" 6275 " -o <OPT>=<VAL> Set LD_<OPT> to <VAL>, without polluting env\n" 6276 " -p Search in PATH for named binary\n" 6277 " -u Ignore LD_ environment variables\n" 6278 " -v Display identification information\n" 6279 " -- End of RTLD options\n" 6280 " <binary> Name of process to execute\n" 6281 " <args> Arguments to the executed process\n", argv0); 6282 } 6283 6284 #define AUXFMT(at, xfmt) [at] = { .name = #at, .fmt = xfmt } 6285 static const struct auxfmt { 6286 const char *name; 6287 const char *fmt; 6288 } auxfmts[] = { 6289 AUXFMT(AT_NULL, NULL), 6290 AUXFMT(AT_IGNORE, NULL), 6291 AUXFMT(AT_EXECFD, "%ld"), 6292 AUXFMT(AT_PHDR, "%p"), 6293 AUXFMT(AT_PHENT, "%lu"), 6294 AUXFMT(AT_PHNUM, "%lu"), 6295 AUXFMT(AT_PAGESZ, "%lu"), 6296 AUXFMT(AT_BASE, "%#lx"), 6297 AUXFMT(AT_FLAGS, "%#lx"), 6298 AUXFMT(AT_ENTRY, "%p"), 6299 AUXFMT(AT_NOTELF, NULL), 6300 AUXFMT(AT_UID, "%ld"), 6301 AUXFMT(AT_EUID, "%ld"), 6302 AUXFMT(AT_GID, "%ld"), 6303 AUXFMT(AT_EGID, "%ld"), 6304 AUXFMT(AT_EXECPATH, "%s"), 6305 AUXFMT(AT_CANARY, "%p"), 6306 AUXFMT(AT_CANARYLEN, "%lu"), 6307 AUXFMT(AT_OSRELDATE, "%lu"), 6308 AUXFMT(AT_NCPUS, "%lu"), 6309 AUXFMT(AT_PAGESIZES, "%p"), 6310 AUXFMT(AT_PAGESIZESLEN, "%lu"), 6311 AUXFMT(AT_TIMEKEEP, "%p"), 6312 AUXFMT(AT_STACKPROT, "%#lx"), 6313 AUXFMT(AT_EHDRFLAGS, "%#lx"), 6314 AUXFMT(AT_HWCAP, "%#lx"), 6315 AUXFMT(AT_HWCAP2, "%#lx"), 6316 AUXFMT(AT_BSDFLAGS, "%#lx"), 6317 AUXFMT(AT_ARGC, "%lu"), 6318 AUXFMT(AT_ARGV, "%p"), 6319 AUXFMT(AT_ENVC, "%p"), 6320 AUXFMT(AT_ENVV, "%p"), 6321 AUXFMT(AT_PS_STRINGS, "%p"), 6322 AUXFMT(AT_FXRNG, "%p"), 6323 AUXFMT(AT_KPRELOAD, "%p"), 6324 AUXFMT(AT_USRSTACKBASE, "%#lx"), 6325 AUXFMT(AT_USRSTACKLIM, "%#lx"), 6326 }; 6327 6328 static bool 6329 is_ptr_fmt(const char *fmt) 6330 { 6331 char last; 6332 6333 last = fmt[strlen(fmt) - 1]; 6334 return (last == 'p' || last == 's'); 6335 } 6336 6337 static void 6338 dump_auxv(Elf_Auxinfo **aux_info) 6339 { 6340 Elf_Auxinfo *auxp; 6341 const struct auxfmt *fmt; 6342 int i; 6343 6344 for (i = 0; i < AT_COUNT; i++) { 6345 auxp = aux_info[i]; 6346 if (auxp == NULL) 6347 continue; 6348 fmt = &auxfmts[i]; 6349 if (fmt->fmt == NULL) 6350 continue; 6351 rtld_fdprintf(STDOUT_FILENO, "%s:\t", fmt->name); 6352 if (is_ptr_fmt(fmt->fmt)) { 6353 rtld_fdprintfx(STDOUT_FILENO, fmt->fmt, 6354 auxp->a_un.a_ptr); 6355 } else { 6356 rtld_fdprintfx(STDOUT_FILENO, fmt->fmt, 6357 auxp->a_un.a_val); 6358 } 6359 rtld_fdprintf(STDOUT_FILENO, "\n"); 6360 } 6361 } 6362 6363 /* 6364 * Overrides for libc_pic-provided functions. 6365 */ 6366 6367 int 6368 __getosreldate(void) 6369 { 6370 size_t len; 6371 int oid[2]; 6372 int error, osrel; 6373 6374 if (osreldate != 0) 6375 return (osreldate); 6376 6377 oid[0] = CTL_KERN; 6378 oid[1] = KERN_OSRELDATE; 6379 osrel = 0; 6380 len = sizeof(osrel); 6381 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 6382 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 6383 osreldate = osrel; 6384 return (osreldate); 6385 } 6386 const char * 6387 rtld_strerror(int errnum) 6388 { 6389 6390 if (errnum < 0 || errnum >= sys_nerr) 6391 return ("Unknown error"); 6392 return (sys_errlist[errnum]); 6393 } 6394 6395 char * 6396 getenv(const char *name) 6397 { 6398 return (__DECONST(char *, rtld_get_env_val(environ, name, 6399 strlen(name)))); 6400 } 6401 6402 /* malloc */ 6403 void * 6404 malloc(size_t nbytes) 6405 { 6406 6407 return (__crt_malloc(nbytes)); 6408 } 6409 6410 void * 6411 calloc(size_t num, size_t size) 6412 { 6413 6414 return (__crt_calloc(num, size)); 6415 } 6416 6417 void 6418 free(void *cp) 6419 { 6420 6421 __crt_free(cp); 6422 } 6423 6424 void * 6425 realloc(void *cp, size_t nbytes) 6426 { 6427 6428 return (__crt_realloc(cp, nbytes)); 6429 } 6430 6431 extern int _rtld_version__FreeBSD_version __exported; 6432 int _rtld_version__FreeBSD_version = __FreeBSD_version; 6433 6434 extern char _rtld_version_laddr_offset __exported; 6435 char _rtld_version_laddr_offset; 6436 6437 extern char _rtld_version_dlpi_tls_data __exported; 6438 char _rtld_version_dlpi_tls_data; 6439