1 /*- 2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra. 3 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>. 4 * Copyright 2009-2012 Konstantin Belousov <kib@FreeBSD.ORG>. 5 * Copyright 2012 John Marino <draco@marino.st>. 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 * 28 * $FreeBSD$ 29 */ 30 31 /* 32 * Dynamic linker for ELF. 33 * 34 * John Polstra <jdp@polstra.com>. 35 */ 36 37 #ifndef __GNUC__ 38 #error "GCC is needed to compile this file" 39 #endif 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_tls.h" 64 #include "rtld_printf.h" 65 #include "notes.h" 66 67 #ifndef COMPAT_32BIT 68 #define PATH_RTLD "/libexec/ld-elf.so.1" 69 #else 70 #define PATH_RTLD "/libexec/ld-elf32.so.1" 71 #endif 72 73 /* Types. */ 74 typedef void (*func_ptr_type)(); 75 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 76 77 /* 78 * Function declarations. 79 */ 80 static const char *basename(const char *); 81 static void die(void) __dead2; 82 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 83 const Elf_Dyn **, const Elf_Dyn **); 84 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *, 85 const Elf_Dyn *); 86 static void digest_dynamic(Obj_Entry *, int); 87 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 88 static Obj_Entry *dlcheck(void *); 89 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, 90 int lo_flags, int mode, RtldLockState *lockstate); 91 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 92 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 93 static bool donelist_check(DoneList *, const Obj_Entry *); 94 static void errmsg_restore(char *); 95 static char *errmsg_save(void); 96 static void *fill_search_info(const char *, size_t, void *); 97 static char *find_library(const char *, const Obj_Entry *, int *); 98 static const char *gethints(bool); 99 static void init_dag(Obj_Entry *); 100 static void init_pagesizes(Elf_Auxinfo **aux_info); 101 static void init_rtld(caddr_t, Elf_Auxinfo **); 102 static void initlist_add_neededs(Needed_Entry *, Objlist *); 103 static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *); 104 static void linkmap_add(Obj_Entry *); 105 static void linkmap_delete(Obj_Entry *); 106 static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 107 static void unload_filtees(Obj_Entry *); 108 static int load_needed_objects(Obj_Entry *, int); 109 static int load_preload_objects(void); 110 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 111 static void map_stacks_exec(RtldLockState *); 112 static Obj_Entry *obj_from_addr(const void *); 113 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 114 static void objlist_call_init(Objlist *, RtldLockState *); 115 static void objlist_clear(Objlist *); 116 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 117 static void objlist_init(Objlist *); 118 static void objlist_push_head(Objlist *, Obj_Entry *); 119 static void objlist_push_tail(Objlist *, Obj_Entry *); 120 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 121 static void objlist_remove(Objlist *, Obj_Entry *); 122 static int parse_libdir(const char *); 123 static void *path_enumerate(const char *, path_enum_proc, void *); 124 static int relocate_object_dag(Obj_Entry *root, bool bind_now, 125 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 126 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 127 int flags, RtldLockState *lockstate); 128 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 129 RtldLockState *); 130 static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now, 131 int flags, RtldLockState *lockstate); 132 static int rtld_dirname(const char *, char *); 133 static int rtld_dirname_abs(const char *, char *); 134 static void *rtld_dlopen(const char *name, int fd, int mode); 135 static void rtld_exit(void); 136 static char *search_library_path(const char *, const char *); 137 static char *search_library_pathfds(const char *, const char *, int *); 138 static const void **get_program_var_addr(const char *, RtldLockState *); 139 static void set_program_var(const char *, const void *); 140 static int symlook_default(SymLook *, const Obj_Entry *refobj); 141 static int symlook_global(SymLook *, DoneList *); 142 static void symlook_init_from_req(SymLook *, const SymLook *); 143 static int symlook_list(SymLook *, const Objlist *, DoneList *); 144 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 145 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 146 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 147 static void trace_loaded_objects(Obj_Entry *); 148 static void unlink_object(Obj_Entry *); 149 static void unload_object(Obj_Entry *); 150 static void unref_dag(Obj_Entry *); 151 static void ref_dag(Obj_Entry *); 152 static char *origin_subst_one(char *, const char *, const char *, bool); 153 static char *origin_subst(char *, const char *); 154 static void preinit_main(void); 155 static int rtld_verify_versions(const Objlist *); 156 static int rtld_verify_object_versions(Obj_Entry *); 157 static void object_add_name(Obj_Entry *, const char *); 158 static int object_match_name(const Obj_Entry *, const char *); 159 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 160 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 161 struct dl_phdr_info *phdr_info); 162 static uint32_t gnu_hash(const char *); 163 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 164 const unsigned long); 165 166 void r_debug_state(struct r_debug *, struct link_map *) __noinline; 167 void _r_debug_postinit(struct link_map *) __noinline; 168 169 /* 170 * Data declarations. 171 */ 172 static char *error_message; /* Message for dlerror(), or NULL */ 173 struct r_debug r_debug; /* for GDB; */ 174 static bool libmap_disable; /* Disable libmap */ 175 static bool ld_loadfltr; /* Immediate filters processing */ 176 static char *libmap_override; /* Maps to use in addition to libmap.conf */ 177 static bool trust; /* False for setuid and setgid programs */ 178 static bool dangerous_ld_env; /* True if environment variables have been 179 used to affect the libraries loaded */ 180 static char *ld_bind_now; /* Environment variable for immediate binding */ 181 static char *ld_debug; /* Environment variable for debugging */ 182 static char *ld_library_path; /* Environment variable for search path */ 183 static char *ld_library_dirs; /* Environment variable for library descriptors */ 184 static char *ld_preload; /* Environment variable for libraries to 185 load first */ 186 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 187 static char *ld_tracing; /* Called from ldd to print libs */ 188 static char *ld_utrace; /* Use utrace() to log events. */ 189 static Obj_Entry *obj_list; /* Head of linked list of shared objects */ 190 static Obj_Entry **obj_tail; /* Link field of last object in list */ 191 static Obj_Entry *obj_main; /* The main program shared object */ 192 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 193 static unsigned int obj_count; /* Number of objects in obj_list */ 194 static unsigned int obj_loads; /* Number of objects in obj_list */ 195 196 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 197 STAILQ_HEAD_INITIALIZER(list_global); 198 static Objlist list_main = /* Objects loaded at program startup */ 199 STAILQ_HEAD_INITIALIZER(list_main); 200 static Objlist list_fini = /* Objects needing fini() calls */ 201 STAILQ_HEAD_INITIALIZER(list_fini); 202 203 Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 204 205 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 206 207 extern Elf_Dyn _DYNAMIC; 208 #pragma weak _DYNAMIC 209 #ifndef RTLD_IS_DYNAMIC 210 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL) 211 #endif 212 213 int npagesizes, osreldate; 214 size_t *pagesizes; 215 216 long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0}; 217 218 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 219 static int max_stack_flags; 220 221 /* 222 * Global declarations normally provided by crt1. The dynamic linker is 223 * not built with crt1, so we have to provide them ourselves. 224 */ 225 char *__progname; 226 char **environ; 227 228 /* 229 * Used to pass argc, argv to init functions. 230 */ 231 int main_argc; 232 char **main_argv; 233 234 /* 235 * Globals to control TLS allocation. 236 */ 237 size_t tls_last_offset; /* Static TLS offset of last module */ 238 size_t tls_last_size; /* Static TLS size of last module */ 239 size_t tls_static_space; /* Static TLS space allocated */ 240 size_t tls_static_max_align; 241 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 242 int tls_max_index = 1; /* Largest module index allocated */ 243 244 bool ld_library_path_rpath = false; 245 246 /* 247 * Fill in a DoneList with an allocation large enough to hold all of 248 * the currently-loaded objects. Keep this as a macro since it calls 249 * alloca and we want that to occur within the scope of the caller. 250 */ 251 #define donelist_init(dlp) \ 252 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 253 assert((dlp)->objs != NULL), \ 254 (dlp)->num_alloc = obj_count, \ 255 (dlp)->num_used = 0) 256 257 #define UTRACE_DLOPEN_START 1 258 #define UTRACE_DLOPEN_STOP 2 259 #define UTRACE_DLCLOSE_START 3 260 #define UTRACE_DLCLOSE_STOP 4 261 #define UTRACE_LOAD_OBJECT 5 262 #define UTRACE_UNLOAD_OBJECT 6 263 #define UTRACE_ADD_RUNDEP 7 264 #define UTRACE_PRELOAD_FINISHED 8 265 #define UTRACE_INIT_CALL 9 266 #define UTRACE_FINI_CALL 10 267 268 struct utrace_rtld { 269 char sig[4]; /* 'RTLD' */ 270 int event; 271 void *handle; 272 void *mapbase; /* Used for 'parent' and 'init/fini' */ 273 size_t mapsize; 274 int refcnt; /* Used for 'mode' */ 275 char name[MAXPATHLEN]; 276 }; 277 278 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 279 if (ld_utrace != NULL) \ 280 ld_utrace_log(e, h, mb, ms, r, n); \ 281 } while (0) 282 283 static void 284 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 285 int refcnt, const char *name) 286 { 287 struct utrace_rtld ut; 288 289 ut.sig[0] = 'R'; 290 ut.sig[1] = 'T'; 291 ut.sig[2] = 'L'; 292 ut.sig[3] = 'D'; 293 ut.event = event; 294 ut.handle = handle; 295 ut.mapbase = mapbase; 296 ut.mapsize = mapsize; 297 ut.refcnt = refcnt; 298 bzero(ut.name, sizeof(ut.name)); 299 if (name) 300 strlcpy(ut.name, name, sizeof(ut.name)); 301 utrace(&ut, sizeof(ut)); 302 } 303 304 /* 305 * Main entry point for dynamic linking. The first argument is the 306 * stack pointer. The stack is expected to be laid out as described 307 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 308 * Specifically, the stack pointer points to a word containing 309 * ARGC. Following that in the stack is a null-terminated sequence 310 * of pointers to argument strings. Then comes a null-terminated 311 * sequence of pointers to environment strings. Finally, there is a 312 * sequence of "auxiliary vector" entries. 313 * 314 * The second argument points to a place to store the dynamic linker's 315 * exit procedure pointer and the third to a place to store the main 316 * program's object. 317 * 318 * The return value is the main program's entry point. 319 */ 320 func_ptr_type 321 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 322 { 323 Elf_Auxinfo *aux_info[AT_COUNT]; 324 int i; 325 int argc; 326 char **argv; 327 char **env; 328 Elf_Auxinfo *aux; 329 Elf_Auxinfo *auxp; 330 const char *argv0; 331 Objlist_Entry *entry; 332 Obj_Entry *obj; 333 Obj_Entry **preload_tail; 334 Obj_Entry *last_interposer; 335 Objlist initlist; 336 RtldLockState lockstate; 337 char *library_path_rpath; 338 int mib[2]; 339 size_t len; 340 341 /* 342 * On entry, the dynamic linker itself has not been relocated yet. 343 * Be very careful not to reference any global data until after 344 * init_rtld has returned. It is OK to reference file-scope statics 345 * and string constants, and to call static and global functions. 346 */ 347 348 /* Find the auxiliary vector on the stack. */ 349 argc = *sp++; 350 argv = (char **) sp; 351 sp += argc + 1; /* Skip over arguments and NULL terminator */ 352 env = (char **) sp; 353 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 354 ; 355 aux = (Elf_Auxinfo *) sp; 356 357 /* Digest the auxiliary vector. */ 358 for (i = 0; i < AT_COUNT; i++) 359 aux_info[i] = NULL; 360 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 361 if (auxp->a_type < AT_COUNT) 362 aux_info[auxp->a_type] = auxp; 363 } 364 365 /* Initialize and relocate ourselves. */ 366 assert(aux_info[AT_BASE] != NULL); 367 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 368 369 __progname = obj_rtld.path; 370 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 371 environ = env; 372 main_argc = argc; 373 main_argv = argv; 374 375 if (aux_info[AT_CANARY] != NULL && 376 aux_info[AT_CANARY]->a_un.a_ptr != NULL) { 377 i = aux_info[AT_CANARYLEN]->a_un.a_val; 378 if (i > sizeof(__stack_chk_guard)) 379 i = sizeof(__stack_chk_guard); 380 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i); 381 } else { 382 mib[0] = CTL_KERN; 383 mib[1] = KERN_ARND; 384 385 len = sizeof(__stack_chk_guard); 386 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 || 387 len != sizeof(__stack_chk_guard)) { 388 /* If sysctl was unsuccessful, use the "terminator canary". */ 389 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0; 390 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0; 391 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n'; 392 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255; 393 } 394 } 395 396 trust = !issetugid(); 397 398 ld_bind_now = getenv(LD_ "BIND_NOW"); 399 /* 400 * If the process is tainted, then we un-set the dangerous environment 401 * variables. The process will be marked as tainted until setuid(2) 402 * is called. If any child process calls setuid(2) we do not want any 403 * future processes to honor the potentially un-safe variables. 404 */ 405 if (!trust) { 406 if (unsetenv(LD_ "PRELOAD") || unsetenv(LD_ "LIBMAP") || 407 unsetenv(LD_ "LIBRARY_PATH") || unsetenv(LD_ "LIBRARY_PATH_FDS") || 408 unsetenv(LD_ "LIBMAP_DISABLE") || 409 unsetenv(LD_ "DEBUG") || unsetenv(LD_ "ELF_HINTS_PATH") || 410 unsetenv(LD_ "LOADFLTR") || unsetenv(LD_ "LIBRARY_PATH_RPATH")) { 411 _rtld_error("environment corrupt; aborting"); 412 die(); 413 } 414 } 415 ld_debug = getenv(LD_ "DEBUG"); 416 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL; 417 libmap_override = getenv(LD_ "LIBMAP"); 418 ld_library_path = getenv(LD_ "LIBRARY_PATH"); 419 ld_library_dirs = getenv(LD_ "LIBRARY_PATH_FDS"); 420 ld_preload = getenv(LD_ "PRELOAD"); 421 ld_elf_hints_path = getenv(LD_ "ELF_HINTS_PATH"); 422 ld_loadfltr = getenv(LD_ "LOADFLTR") != NULL; 423 library_path_rpath = getenv(LD_ "LIBRARY_PATH_RPATH"); 424 if (library_path_rpath != NULL) { 425 if (library_path_rpath[0] == 'y' || 426 library_path_rpath[0] == 'Y' || 427 library_path_rpath[0] == '1') 428 ld_library_path_rpath = true; 429 else 430 ld_library_path_rpath = false; 431 } 432 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 433 (ld_library_path != NULL) || (ld_preload != NULL) || 434 (ld_elf_hints_path != NULL) || ld_loadfltr; 435 ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS"); 436 ld_utrace = getenv(LD_ "UTRACE"); 437 438 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 439 ld_elf_hints_path = _PATH_ELF_HINTS; 440 441 if (ld_debug != NULL && *ld_debug != '\0') 442 debug = 1; 443 dbg("%s is initialized, base address = %p", __progname, 444 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 445 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 446 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 447 448 dbg("initializing thread locks"); 449 lockdflt_init(); 450 451 /* 452 * Load the main program, or process its program header if it is 453 * already loaded. 454 */ 455 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */ 456 int fd = aux_info[AT_EXECFD]->a_un.a_val; 457 dbg("loading main program"); 458 obj_main = map_object(fd, argv0, NULL); 459 close(fd); 460 if (obj_main == NULL) 461 die(); 462 max_stack_flags = obj->stack_flags; 463 } else { /* Main program already loaded. */ 464 const Elf_Phdr *phdr; 465 int phnum; 466 caddr_t entry; 467 468 dbg("processing main program's program header"); 469 assert(aux_info[AT_PHDR] != NULL); 470 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 471 assert(aux_info[AT_PHNUM] != NULL); 472 phnum = aux_info[AT_PHNUM]->a_un.a_val; 473 assert(aux_info[AT_PHENT] != NULL); 474 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 475 assert(aux_info[AT_ENTRY] != NULL); 476 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 477 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL) 478 die(); 479 } 480 481 if (aux_info[AT_EXECPATH] != 0) { 482 char *kexecpath; 483 char buf[MAXPATHLEN]; 484 485 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 486 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 487 if (kexecpath[0] == '/') 488 obj_main->path = kexecpath; 489 else if (getcwd(buf, sizeof(buf)) == NULL || 490 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 491 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 492 obj_main->path = xstrdup(argv0); 493 else 494 obj_main->path = xstrdup(buf); 495 } else { 496 dbg("No AT_EXECPATH"); 497 obj_main->path = xstrdup(argv0); 498 } 499 dbg("obj_main path %s", obj_main->path); 500 obj_main->mainprog = true; 501 502 if (aux_info[AT_STACKPROT] != NULL && 503 aux_info[AT_STACKPROT]->a_un.a_val != 0) 504 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 505 506 /* 507 * Get the actual dynamic linker pathname from the executable if 508 * possible. (It should always be possible.) That ensures that 509 * gdb will find the right dynamic linker even if a non-standard 510 * one is being used. 511 */ 512 if (obj_main->interp != NULL && 513 strcmp(obj_main->interp, obj_rtld.path) != 0) { 514 free(obj_rtld.path); 515 obj_rtld.path = xstrdup(obj_main->interp); 516 __progname = obj_rtld.path; 517 } 518 519 digest_dynamic(obj_main, 0); 520 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 521 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 522 obj_main->dynsymcount); 523 524 linkmap_add(obj_main); 525 linkmap_add(&obj_rtld); 526 527 /* Link the main program into the list of objects. */ 528 *obj_tail = obj_main; 529 obj_tail = &obj_main->next; 530 obj_count++; 531 obj_loads++; 532 533 /* Initialize a fake symbol for resolving undefined weak references. */ 534 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 535 sym_zero.st_shndx = SHN_UNDEF; 536 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 537 538 if (!libmap_disable) 539 libmap_disable = (bool)lm_init(libmap_override); 540 541 dbg("loading LD_PRELOAD libraries"); 542 if (load_preload_objects() == -1) 543 die(); 544 preload_tail = obj_tail; 545 546 dbg("loading needed objects"); 547 if (load_needed_objects(obj_main, 0) == -1) 548 die(); 549 550 /* Make a list of all objects loaded at startup. */ 551 last_interposer = obj_main; 552 for (obj = obj_list; obj != NULL; obj = obj->next) { 553 if (obj->z_interpose && obj != obj_main) { 554 objlist_put_after(&list_main, last_interposer, obj); 555 last_interposer = obj; 556 } else { 557 objlist_push_tail(&list_main, obj); 558 } 559 obj->refcount++; 560 } 561 562 dbg("checking for required versions"); 563 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 564 die(); 565 566 if (ld_tracing) { /* We're done */ 567 trace_loaded_objects(obj_main); 568 exit(0); 569 } 570 571 if (getenv(LD_ "DUMP_REL_PRE") != NULL) { 572 dump_relocations(obj_main); 573 exit (0); 574 } 575 576 /* 577 * Processing tls relocations requires having the tls offsets 578 * initialized. Prepare offsets before starting initial 579 * relocation processing. 580 */ 581 dbg("initializing initial thread local storage offsets"); 582 STAILQ_FOREACH(entry, &list_main, link) { 583 /* 584 * Allocate all the initial objects out of the static TLS 585 * block even if they didn't ask for it. 586 */ 587 allocate_tls_offset(entry->obj); 588 } 589 590 if (relocate_objects(obj_main, 591 ld_bind_now != NULL && *ld_bind_now != '\0', 592 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 593 die(); 594 595 dbg("doing copy relocations"); 596 if (do_copy_relocations(obj_main) == -1) 597 die(); 598 599 if (getenv(LD_ "DUMP_REL_POST") != NULL) { 600 dump_relocations(obj_main); 601 exit (0); 602 } 603 604 /* 605 * Setup TLS for main thread. This must be done after the 606 * relocations are processed, since tls initialization section 607 * might be the subject for relocations. 608 */ 609 dbg("initializing initial thread local storage"); 610 allocate_initial_tls(obj_list); 611 612 dbg("initializing key program variables"); 613 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 614 set_program_var("environ", env); 615 set_program_var("__elf_aux_vector", aux); 616 617 /* Make a list of init functions to call. */ 618 objlist_init(&initlist); 619 initlist_add_objects(obj_list, preload_tail, &initlist); 620 621 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 622 623 map_stacks_exec(NULL); 624 625 dbg("resolving ifuncs"); 626 if (resolve_objects_ifunc(obj_main, 627 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY, 628 NULL) == -1) 629 die(); 630 631 if (!obj_main->crt_no_init) { 632 /* 633 * Make sure we don't call the main program's init and fini 634 * functions for binaries linked with old crt1 which calls 635 * _init itself. 636 */ 637 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 638 obj_main->preinit_array = obj_main->init_array = 639 obj_main->fini_array = (Elf_Addr)NULL; 640 } 641 642 wlock_acquire(rtld_bind_lock, &lockstate); 643 if (obj_main->crt_no_init) 644 preinit_main(); 645 objlist_call_init(&initlist, &lockstate); 646 _r_debug_postinit(&obj_main->linkmap); 647 objlist_clear(&initlist); 648 dbg("loading filtees"); 649 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 650 if (ld_loadfltr || obj->z_loadfltr) 651 load_filtees(obj, 0, &lockstate); 652 } 653 lock_release(rtld_bind_lock, &lockstate); 654 655 dbg("transferring control to program entry point = %p", obj_main->entry); 656 657 /* Return the exit procedure and the program entry point. */ 658 *exit_proc = rtld_exit; 659 *objp = obj_main; 660 return (func_ptr_type) obj_main->entry; 661 } 662 663 void * 664 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 665 { 666 void *ptr; 667 Elf_Addr target; 668 669 ptr = (void *)make_function_pointer(def, obj); 670 target = ((Elf_Addr (*)(void))ptr)(); 671 return ((void *)target); 672 } 673 674 Elf_Addr 675 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 676 { 677 const Elf_Rel *rel; 678 const Elf_Sym *def; 679 const Obj_Entry *defobj; 680 Elf_Addr *where; 681 Elf_Addr target; 682 RtldLockState lockstate; 683 684 rlock_acquire(rtld_bind_lock, &lockstate); 685 if (sigsetjmp(lockstate.env, 0) != 0) 686 lock_upgrade(rtld_bind_lock, &lockstate); 687 if (obj->pltrel) 688 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 689 else 690 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 691 692 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 693 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL, 694 &lockstate); 695 if (def == NULL) 696 die(); 697 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 698 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 699 else 700 target = (Elf_Addr)(defobj->relocbase + def->st_value); 701 702 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 703 defobj->strtab + def->st_name, basename(obj->path), 704 (void *)target, basename(defobj->path)); 705 706 /* 707 * Write the new contents for the jmpslot. Note that depending on 708 * architecture, the value which we need to return back to the 709 * lazy binding trampoline may or may not be the target 710 * address. The value returned from reloc_jmpslot() is the value 711 * that the trampoline needs. 712 */ 713 target = reloc_jmpslot(where, target, defobj, obj, rel); 714 lock_release(rtld_bind_lock, &lockstate); 715 return target; 716 } 717 718 /* 719 * Error reporting function. Use it like printf. If formats the message 720 * into a buffer, and sets things up so that the next call to dlerror() 721 * will return the message. 722 */ 723 void 724 _rtld_error(const char *fmt, ...) 725 { 726 static char buf[512]; 727 va_list ap; 728 729 va_start(ap, fmt); 730 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 731 error_message = buf; 732 va_end(ap); 733 } 734 735 /* 736 * Return a dynamically-allocated copy of the current error message, if any. 737 */ 738 static char * 739 errmsg_save(void) 740 { 741 return error_message == NULL ? NULL : xstrdup(error_message); 742 } 743 744 /* 745 * Restore the current error message from a copy which was previously saved 746 * by errmsg_save(). The copy is freed. 747 */ 748 static void 749 errmsg_restore(char *saved_msg) 750 { 751 if (saved_msg == NULL) 752 error_message = NULL; 753 else { 754 _rtld_error("%s", saved_msg); 755 free(saved_msg); 756 } 757 } 758 759 static const char * 760 basename(const char *name) 761 { 762 const char *p = strrchr(name, '/'); 763 return p != NULL ? p + 1 : name; 764 } 765 766 static struct utsname uts; 767 768 static char * 769 origin_subst_one(char *real, const char *kw, const char *subst, 770 bool may_free) 771 { 772 char *p, *p1, *res, *resp; 773 int subst_len, kw_len, subst_count, old_len, new_len; 774 775 kw_len = strlen(kw); 776 777 /* 778 * First, count the number of the keyword occurences, to 779 * preallocate the final string. 780 */ 781 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 782 p1 = strstr(p, kw); 783 if (p1 == NULL) 784 break; 785 } 786 787 /* 788 * If the keyword is not found, just return. 789 */ 790 if (subst_count == 0) 791 return (may_free ? real : xstrdup(real)); 792 793 /* 794 * There is indeed something to substitute. Calculate the 795 * length of the resulting string, and allocate it. 796 */ 797 subst_len = strlen(subst); 798 old_len = strlen(real); 799 new_len = old_len + (subst_len - kw_len) * subst_count; 800 res = xmalloc(new_len + 1); 801 802 /* 803 * Now, execute the substitution loop. 804 */ 805 for (p = real, resp = res, *resp = '\0';;) { 806 p1 = strstr(p, kw); 807 if (p1 != NULL) { 808 /* Copy the prefix before keyword. */ 809 memcpy(resp, p, p1 - p); 810 resp += p1 - p; 811 /* Keyword replacement. */ 812 memcpy(resp, subst, subst_len); 813 resp += subst_len; 814 *resp = '\0'; 815 p = p1 + kw_len; 816 } else 817 break; 818 } 819 820 /* Copy to the end of string and finish. */ 821 strcat(resp, p); 822 if (may_free) 823 free(real); 824 return (res); 825 } 826 827 static char * 828 origin_subst(char *real, const char *origin_path) 829 { 830 char *res1, *res2, *res3, *res4; 831 832 if (uts.sysname[0] == '\0') { 833 if (uname(&uts) != 0) { 834 _rtld_error("utsname failed: %d", errno); 835 return (NULL); 836 } 837 } 838 res1 = origin_subst_one(real, "$ORIGIN", origin_path, false); 839 res2 = origin_subst_one(res1, "$OSNAME", uts.sysname, true); 840 res3 = origin_subst_one(res2, "$OSREL", uts.release, true); 841 res4 = origin_subst_one(res3, "$PLATFORM", uts.machine, true); 842 return (res4); 843 } 844 845 static void 846 die(void) 847 { 848 const char *msg = dlerror(); 849 850 if (msg == NULL) 851 msg = "Fatal error"; 852 rtld_fdputstr(STDERR_FILENO, msg); 853 rtld_fdputchar(STDERR_FILENO, '\n'); 854 _exit(1); 855 } 856 857 /* 858 * Process a shared object's DYNAMIC section, and save the important 859 * information in its Obj_Entry structure. 860 */ 861 static void 862 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 863 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 864 { 865 const Elf_Dyn *dynp; 866 Needed_Entry **needed_tail = &obj->needed; 867 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 868 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 869 const Elf_Hashelt *hashtab; 870 const Elf32_Word *hashval; 871 Elf32_Word bkt, nmaskwords; 872 int bloom_size32; 873 bool nmw_power2; 874 int plttype = DT_REL; 875 876 *dyn_rpath = NULL; 877 *dyn_soname = NULL; 878 *dyn_runpath = NULL; 879 880 obj->bind_now = false; 881 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 882 switch (dynp->d_tag) { 883 884 case DT_REL: 885 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 886 break; 887 888 case DT_RELSZ: 889 obj->relsize = dynp->d_un.d_val; 890 break; 891 892 case DT_RELENT: 893 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 894 break; 895 896 case DT_JMPREL: 897 obj->pltrel = (const Elf_Rel *) 898 (obj->relocbase + dynp->d_un.d_ptr); 899 break; 900 901 case DT_PLTRELSZ: 902 obj->pltrelsize = dynp->d_un.d_val; 903 break; 904 905 case DT_RELA: 906 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 907 break; 908 909 case DT_RELASZ: 910 obj->relasize = dynp->d_un.d_val; 911 break; 912 913 case DT_RELAENT: 914 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 915 break; 916 917 case DT_PLTREL: 918 plttype = dynp->d_un.d_val; 919 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 920 break; 921 922 case DT_SYMTAB: 923 obj->symtab = (const Elf_Sym *) 924 (obj->relocbase + dynp->d_un.d_ptr); 925 break; 926 927 case DT_SYMENT: 928 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 929 break; 930 931 case DT_STRTAB: 932 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 933 break; 934 935 case DT_STRSZ: 936 obj->strsize = dynp->d_un.d_val; 937 break; 938 939 case DT_VERNEED: 940 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 941 dynp->d_un.d_val); 942 break; 943 944 case DT_VERNEEDNUM: 945 obj->verneednum = dynp->d_un.d_val; 946 break; 947 948 case DT_VERDEF: 949 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 950 dynp->d_un.d_val); 951 break; 952 953 case DT_VERDEFNUM: 954 obj->verdefnum = dynp->d_un.d_val; 955 break; 956 957 case DT_VERSYM: 958 obj->versyms = (const Elf_Versym *)(obj->relocbase + 959 dynp->d_un.d_val); 960 break; 961 962 case DT_HASH: 963 { 964 hashtab = (const Elf_Hashelt *)(obj->relocbase + 965 dynp->d_un.d_ptr); 966 obj->nbuckets = hashtab[0]; 967 obj->nchains = hashtab[1]; 968 obj->buckets = hashtab + 2; 969 obj->chains = obj->buckets + obj->nbuckets; 970 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 971 obj->buckets != NULL; 972 } 973 break; 974 975 case DT_GNU_HASH: 976 { 977 hashtab = (const Elf_Hashelt *)(obj->relocbase + 978 dynp->d_un.d_ptr); 979 obj->nbuckets_gnu = hashtab[0]; 980 obj->symndx_gnu = hashtab[1]; 981 nmaskwords = hashtab[2]; 982 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 983 /* Number of bitmask words is required to be power of 2 */ 984 nmw_power2 = ((nmaskwords & (nmaskwords - 1)) == 0); 985 obj->maskwords_bm_gnu = nmaskwords - 1; 986 obj->shift2_gnu = hashtab[3]; 987 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4); 988 obj->buckets_gnu = hashtab + 4 + bloom_size32; 989 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 990 obj->symndx_gnu; 991 obj->valid_hash_gnu = nmw_power2 && obj->nbuckets_gnu > 0 && 992 obj->buckets_gnu != NULL; 993 } 994 break; 995 996 case DT_NEEDED: 997 if (!obj->rtld) { 998 Needed_Entry *nep = NEW(Needed_Entry); 999 nep->name = dynp->d_un.d_val; 1000 nep->obj = NULL; 1001 nep->next = NULL; 1002 1003 *needed_tail = nep; 1004 needed_tail = &nep->next; 1005 } 1006 break; 1007 1008 case DT_FILTER: 1009 if (!obj->rtld) { 1010 Needed_Entry *nep = NEW(Needed_Entry); 1011 nep->name = dynp->d_un.d_val; 1012 nep->obj = NULL; 1013 nep->next = NULL; 1014 1015 *needed_filtees_tail = nep; 1016 needed_filtees_tail = &nep->next; 1017 } 1018 break; 1019 1020 case DT_AUXILIARY: 1021 if (!obj->rtld) { 1022 Needed_Entry *nep = NEW(Needed_Entry); 1023 nep->name = dynp->d_un.d_val; 1024 nep->obj = NULL; 1025 nep->next = NULL; 1026 1027 *needed_aux_filtees_tail = nep; 1028 needed_aux_filtees_tail = &nep->next; 1029 } 1030 break; 1031 1032 case DT_PLTGOT: 1033 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 1034 break; 1035 1036 case DT_TEXTREL: 1037 obj->textrel = true; 1038 break; 1039 1040 case DT_SYMBOLIC: 1041 obj->symbolic = true; 1042 break; 1043 1044 case DT_RPATH: 1045 /* 1046 * We have to wait until later to process this, because we 1047 * might not have gotten the address of the string table yet. 1048 */ 1049 *dyn_rpath = dynp; 1050 break; 1051 1052 case DT_SONAME: 1053 *dyn_soname = dynp; 1054 break; 1055 1056 case DT_RUNPATH: 1057 *dyn_runpath = dynp; 1058 break; 1059 1060 case DT_INIT: 1061 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1062 break; 1063 1064 case DT_PREINIT_ARRAY: 1065 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1066 break; 1067 1068 case DT_PREINIT_ARRAYSZ: 1069 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1070 break; 1071 1072 case DT_INIT_ARRAY: 1073 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1074 break; 1075 1076 case DT_INIT_ARRAYSZ: 1077 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1078 break; 1079 1080 case DT_FINI: 1081 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1082 break; 1083 1084 case DT_FINI_ARRAY: 1085 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1086 break; 1087 1088 case DT_FINI_ARRAYSZ: 1089 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1090 break; 1091 1092 /* 1093 * Don't process DT_DEBUG on MIPS as the dynamic section 1094 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1095 */ 1096 1097 #ifndef __mips__ 1098 case DT_DEBUG: 1099 /* XXX - not implemented yet */ 1100 if (!early) 1101 dbg("Filling in DT_DEBUG entry"); 1102 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 1103 break; 1104 #endif 1105 1106 case DT_FLAGS: 1107 if ((dynp->d_un.d_val & DF_ORIGIN) && trust) 1108 obj->z_origin = true; 1109 if (dynp->d_un.d_val & DF_SYMBOLIC) 1110 obj->symbolic = true; 1111 if (dynp->d_un.d_val & DF_TEXTREL) 1112 obj->textrel = true; 1113 if (dynp->d_un.d_val & DF_BIND_NOW) 1114 obj->bind_now = true; 1115 /*if (dynp->d_un.d_val & DF_STATIC_TLS) 1116 ;*/ 1117 break; 1118 #ifdef __mips__ 1119 case DT_MIPS_LOCAL_GOTNO: 1120 obj->local_gotno = dynp->d_un.d_val; 1121 break; 1122 1123 case DT_MIPS_SYMTABNO: 1124 obj->symtabno = dynp->d_un.d_val; 1125 break; 1126 1127 case DT_MIPS_GOTSYM: 1128 obj->gotsym = dynp->d_un.d_val; 1129 break; 1130 1131 case DT_MIPS_RLD_MAP: 1132 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1133 break; 1134 #endif 1135 1136 case DT_FLAGS_1: 1137 if (dynp->d_un.d_val & DF_1_NOOPEN) 1138 obj->z_noopen = true; 1139 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust) 1140 obj->z_origin = true; 1141 /*if (dynp->d_un.d_val & DF_1_GLOBAL) 1142 XXX ;*/ 1143 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1144 obj->bind_now = true; 1145 if (dynp->d_un.d_val & DF_1_NODELETE) 1146 obj->z_nodelete = true; 1147 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1148 obj->z_loadfltr = true; 1149 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1150 obj->z_interpose = true; 1151 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1152 obj->z_nodeflib = true; 1153 break; 1154 1155 default: 1156 if (!early) { 1157 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1158 (long)dynp->d_tag); 1159 } 1160 break; 1161 } 1162 } 1163 1164 obj->traced = false; 1165 1166 if (plttype == DT_RELA) { 1167 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1168 obj->pltrel = NULL; 1169 obj->pltrelasize = obj->pltrelsize; 1170 obj->pltrelsize = 0; 1171 } 1172 1173 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1174 if (obj->valid_hash_sysv) 1175 obj->dynsymcount = obj->nchains; 1176 else if (obj->valid_hash_gnu) { 1177 obj->dynsymcount = 0; 1178 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1179 if (obj->buckets_gnu[bkt] == 0) 1180 continue; 1181 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1182 do 1183 obj->dynsymcount++; 1184 while ((*hashval++ & 1u) == 0); 1185 } 1186 obj->dynsymcount += obj->symndx_gnu; 1187 } 1188 } 1189 1190 static void 1191 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1192 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1193 { 1194 1195 if (obj->z_origin && obj->origin_path == NULL) { 1196 obj->origin_path = xmalloc(PATH_MAX); 1197 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1) 1198 die(); 1199 } 1200 1201 if (dyn_runpath != NULL) { 1202 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val; 1203 if (obj->z_origin) 1204 obj->runpath = origin_subst(obj->runpath, obj->origin_path); 1205 } 1206 else if (dyn_rpath != NULL) { 1207 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 1208 if (obj->z_origin) 1209 obj->rpath = origin_subst(obj->rpath, obj->origin_path); 1210 } 1211 1212 if (dyn_soname != NULL) 1213 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1214 } 1215 1216 static void 1217 digest_dynamic(Obj_Entry *obj, int early) 1218 { 1219 const Elf_Dyn *dyn_rpath; 1220 const Elf_Dyn *dyn_soname; 1221 const Elf_Dyn *dyn_runpath; 1222 1223 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1224 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath); 1225 } 1226 1227 /* 1228 * Process a shared object's program header. This is used only for the 1229 * main program, when the kernel has already loaded the main program 1230 * into memory before calling the dynamic linker. It creates and 1231 * returns an Obj_Entry structure. 1232 */ 1233 static Obj_Entry * 1234 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1235 { 1236 Obj_Entry *obj; 1237 const Elf_Phdr *phlimit = phdr + phnum; 1238 const Elf_Phdr *ph; 1239 Elf_Addr note_start, note_end; 1240 int nsegs = 0; 1241 1242 obj = obj_new(); 1243 for (ph = phdr; ph < phlimit; ph++) { 1244 if (ph->p_type != PT_PHDR) 1245 continue; 1246 1247 obj->phdr = phdr; 1248 obj->phsize = ph->p_memsz; 1249 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1250 break; 1251 } 1252 1253 obj->stack_flags = PF_X | PF_R | PF_W; 1254 1255 for (ph = phdr; ph < phlimit; ph++) { 1256 switch (ph->p_type) { 1257 1258 case PT_INTERP: 1259 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1260 break; 1261 1262 case PT_LOAD: 1263 if (nsegs == 0) { /* First load segment */ 1264 obj->vaddrbase = trunc_page(ph->p_vaddr); 1265 obj->mapbase = obj->vaddrbase + obj->relocbase; 1266 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1267 obj->vaddrbase; 1268 } else { /* Last load segment */ 1269 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1270 obj->vaddrbase; 1271 } 1272 nsegs++; 1273 break; 1274 1275 case PT_DYNAMIC: 1276 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1277 break; 1278 1279 case PT_TLS: 1280 obj->tlsindex = 1; 1281 obj->tlssize = ph->p_memsz; 1282 obj->tlsalign = ph->p_align; 1283 obj->tlsinitsize = ph->p_filesz; 1284 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1285 break; 1286 1287 case PT_GNU_STACK: 1288 obj->stack_flags = ph->p_flags; 1289 break; 1290 1291 case PT_GNU_RELRO: 1292 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1293 obj->relro_size = round_page(ph->p_memsz); 1294 break; 1295 1296 case PT_NOTE: 1297 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1298 note_end = note_start + ph->p_filesz; 1299 digest_notes(obj, note_start, note_end); 1300 break; 1301 } 1302 } 1303 if (nsegs < 1) { 1304 _rtld_error("%s: too few PT_LOAD segments", path); 1305 return NULL; 1306 } 1307 1308 obj->entry = entry; 1309 return obj; 1310 } 1311 1312 void 1313 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1314 { 1315 const Elf_Note *note; 1316 const char *note_name; 1317 uintptr_t p; 1318 1319 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1320 note = (const Elf_Note *)((const char *)(note + 1) + 1321 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1322 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1323 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1324 note->n_descsz != sizeof(int32_t)) 1325 continue; 1326 if (note->n_type != ABI_NOTETYPE && 1327 note->n_type != CRT_NOINIT_NOTETYPE) 1328 continue; 1329 note_name = (const char *)(note + 1); 1330 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1331 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1332 continue; 1333 switch (note->n_type) { 1334 case ABI_NOTETYPE: 1335 /* FreeBSD osrel note */ 1336 p = (uintptr_t)(note + 1); 1337 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1338 obj->osrel = *(const int32_t *)(p); 1339 dbg("note osrel %d", obj->osrel); 1340 break; 1341 case CRT_NOINIT_NOTETYPE: 1342 /* FreeBSD 'crt does not call init' note */ 1343 obj->crt_no_init = true; 1344 dbg("note crt_no_init"); 1345 break; 1346 } 1347 } 1348 } 1349 1350 static Obj_Entry * 1351 dlcheck(void *handle) 1352 { 1353 Obj_Entry *obj; 1354 1355 for (obj = obj_list; obj != NULL; obj = obj->next) 1356 if (obj == (Obj_Entry *) handle) 1357 break; 1358 1359 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1360 _rtld_error("Invalid shared object handle %p", handle); 1361 return NULL; 1362 } 1363 return obj; 1364 } 1365 1366 /* 1367 * If the given object is already in the donelist, return true. Otherwise 1368 * add the object to the list and return false. 1369 */ 1370 static bool 1371 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1372 { 1373 unsigned int i; 1374 1375 for (i = 0; i < dlp->num_used; i++) 1376 if (dlp->objs[i] == obj) 1377 return true; 1378 /* 1379 * Our donelist allocation should always be sufficient. But if 1380 * our threads locking isn't working properly, more shared objects 1381 * could have been loaded since we allocated the list. That should 1382 * never happen, but we'll handle it properly just in case it does. 1383 */ 1384 if (dlp->num_used < dlp->num_alloc) 1385 dlp->objs[dlp->num_used++] = obj; 1386 return false; 1387 } 1388 1389 /* 1390 * Hash function for symbol table lookup. Don't even think about changing 1391 * this. It is specified by the System V ABI. 1392 */ 1393 unsigned long 1394 elf_hash(const char *name) 1395 { 1396 const unsigned char *p = (const unsigned char *) name; 1397 unsigned long h = 0; 1398 unsigned long g; 1399 1400 while (*p != '\0') { 1401 h = (h << 4) + *p++; 1402 if ((g = h & 0xf0000000) != 0) 1403 h ^= g >> 24; 1404 h &= ~g; 1405 } 1406 return h; 1407 } 1408 1409 /* 1410 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1411 * unsigned in case it's implemented with a wider type. 1412 */ 1413 static uint32_t 1414 gnu_hash(const char *s) 1415 { 1416 uint32_t h; 1417 unsigned char c; 1418 1419 h = 5381; 1420 for (c = *s; c != '\0'; c = *++s) 1421 h = h * 33 + c; 1422 return (h & 0xffffffff); 1423 } 1424 1425 1426 /* 1427 * Find the library with the given name, and return its full pathname. 1428 * The returned string is dynamically allocated. Generates an error 1429 * message and returns NULL if the library cannot be found. 1430 * 1431 * If the second argument is non-NULL, then it refers to an already- 1432 * loaded shared object, whose library search path will be searched. 1433 * 1434 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1435 * descriptor (which is close-on-exec) will be passed out via the third 1436 * argument. 1437 * 1438 * The search order is: 1439 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1440 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1441 * LD_LIBRARY_PATH 1442 * DT_RUNPATH in the referencing file 1443 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1444 * from list) 1445 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1446 * 1447 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1448 */ 1449 static char * 1450 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1451 { 1452 char *pathname; 1453 char *name; 1454 bool nodeflib, objgiven; 1455 1456 objgiven = refobj != NULL; 1457 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */ 1458 if (xname[0] != '/' && !trust) { 1459 _rtld_error("Absolute pathname required for shared object \"%s\"", 1460 xname); 1461 return NULL; 1462 } 1463 if (objgiven && refobj->z_origin) { 1464 return (origin_subst(__DECONST(char *, xname), 1465 refobj->origin_path)); 1466 } else { 1467 return (xstrdup(xname)); 1468 } 1469 } 1470 1471 if (libmap_disable || !objgiven || 1472 (name = lm_find(refobj->path, xname)) == NULL) 1473 name = (char *)xname; 1474 1475 dbg(" Searching for \"%s\"", name); 1476 1477 /* 1478 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1479 * back to pre-conforming behaviour if user requested so with 1480 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1481 * nodeflib. 1482 */ 1483 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1484 if ((pathname = search_library_path(name, ld_library_path)) != NULL || 1485 (refobj != NULL && 1486 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1487 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL || 1488 (pathname = search_library_path(name, gethints(false))) != NULL || 1489 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL) 1490 return (pathname); 1491 } else { 1492 nodeflib = objgiven ? refobj->z_nodeflib : false; 1493 if ((objgiven && 1494 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1495 (objgiven && refobj->runpath == NULL && refobj != obj_main && 1496 (pathname = search_library_path(name, obj_main->rpath)) != NULL) || 1497 (pathname = search_library_path(name, ld_library_path)) != NULL || 1498 (objgiven && 1499 (pathname = search_library_path(name, refobj->runpath)) != NULL) || 1500 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL || 1501 (pathname = search_library_path(name, gethints(nodeflib))) != NULL || 1502 (objgiven && !nodeflib && 1503 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)) 1504 return (pathname); 1505 } 1506 1507 if (objgiven && refobj->path != NULL) { 1508 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 1509 name, basename(refobj->path)); 1510 } else { 1511 _rtld_error("Shared object \"%s\" not found", name); 1512 } 1513 return NULL; 1514 } 1515 1516 /* 1517 * Given a symbol number in a referencing object, find the corresponding 1518 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1519 * no definition was found. Returns a pointer to the Obj_Entry of the 1520 * defining object via the reference parameter DEFOBJ_OUT. 1521 */ 1522 const Elf_Sym * 1523 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1524 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1525 RtldLockState *lockstate) 1526 { 1527 const Elf_Sym *ref; 1528 const Elf_Sym *def; 1529 const Obj_Entry *defobj; 1530 SymLook req; 1531 const char *name; 1532 int res; 1533 1534 /* 1535 * If we have already found this symbol, get the information from 1536 * the cache. 1537 */ 1538 if (symnum >= refobj->dynsymcount) 1539 return NULL; /* Bad object */ 1540 if (cache != NULL && cache[symnum].sym != NULL) { 1541 *defobj_out = cache[symnum].obj; 1542 return cache[symnum].sym; 1543 } 1544 1545 ref = refobj->symtab + symnum; 1546 name = refobj->strtab + ref->st_name; 1547 def = NULL; 1548 defobj = NULL; 1549 1550 /* 1551 * We don't have to do a full scale lookup if the symbol is local. 1552 * We know it will bind to the instance in this load module; to 1553 * which we already have a pointer (ie ref). By not doing a lookup, 1554 * we not only improve performance, but it also avoids unresolvable 1555 * symbols when local symbols are not in the hash table. This has 1556 * been seen with the ia64 toolchain. 1557 */ 1558 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1559 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1560 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1561 symnum); 1562 } 1563 symlook_init(&req, name); 1564 req.flags = flags; 1565 req.ventry = fetch_ventry(refobj, symnum); 1566 req.lockstate = lockstate; 1567 res = symlook_default(&req, refobj); 1568 if (res == 0) { 1569 def = req.sym_out; 1570 defobj = req.defobj_out; 1571 } 1572 } else { 1573 def = ref; 1574 defobj = refobj; 1575 } 1576 1577 /* 1578 * If we found no definition and the reference is weak, treat the 1579 * symbol as having the value zero. 1580 */ 1581 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1582 def = &sym_zero; 1583 defobj = obj_main; 1584 } 1585 1586 if (def != NULL) { 1587 *defobj_out = defobj; 1588 /* Record the information in the cache to avoid subsequent lookups. */ 1589 if (cache != NULL) { 1590 cache[symnum].sym = def; 1591 cache[symnum].obj = defobj; 1592 } 1593 } else { 1594 if (refobj != &obj_rtld) 1595 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name); 1596 } 1597 return def; 1598 } 1599 1600 /* 1601 * Return the search path from the ldconfig hints file, reading it if 1602 * necessary. If nostdlib is true, then the default search paths are 1603 * not added to result. 1604 * 1605 * Returns NULL if there are problems with the hints file, 1606 * or if the search path there is empty. 1607 */ 1608 static const char * 1609 gethints(bool nostdlib) 1610 { 1611 static char *hints, *filtered_path; 1612 struct elfhints_hdr hdr; 1613 struct fill_search_info_args sargs, hargs; 1614 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1615 struct dl_serpath *SLPpath, *hintpath; 1616 char *p; 1617 unsigned int SLPndx, hintndx, fndx, fcount; 1618 int fd; 1619 size_t flen; 1620 bool skip; 1621 1622 /* First call, read the hints file */ 1623 if (hints == NULL) { 1624 /* Keep from trying again in case the hints file is bad. */ 1625 hints = ""; 1626 1627 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1628 return (NULL); 1629 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1630 hdr.magic != ELFHINTS_MAGIC || 1631 hdr.version != 1) { 1632 close(fd); 1633 return (NULL); 1634 } 1635 p = xmalloc(hdr.dirlistlen + 1); 1636 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1637 read(fd, p, hdr.dirlistlen + 1) != 1638 (ssize_t)hdr.dirlistlen + 1) { 1639 free(p); 1640 close(fd); 1641 return (NULL); 1642 } 1643 hints = p; 1644 close(fd); 1645 } 1646 1647 /* 1648 * If caller agreed to receive list which includes the default 1649 * paths, we are done. Otherwise, if we still did not 1650 * calculated filtered result, do it now. 1651 */ 1652 if (!nostdlib) 1653 return (hints[0] != '\0' ? hints : NULL); 1654 if (filtered_path != NULL) 1655 goto filt_ret; 1656 1657 /* 1658 * Obtain the list of all configured search paths, and the 1659 * list of the default paths. 1660 * 1661 * First estimate the size of the results. 1662 */ 1663 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1664 smeta.dls_cnt = 0; 1665 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1666 hmeta.dls_cnt = 0; 1667 1668 sargs.request = RTLD_DI_SERINFOSIZE; 1669 sargs.serinfo = &smeta; 1670 hargs.request = RTLD_DI_SERINFOSIZE; 1671 hargs.serinfo = &hmeta; 1672 1673 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1674 path_enumerate(p, fill_search_info, &hargs); 1675 1676 SLPinfo = xmalloc(smeta.dls_size); 1677 hintinfo = xmalloc(hmeta.dls_size); 1678 1679 /* 1680 * Next fetch both sets of paths. 1681 */ 1682 sargs.request = RTLD_DI_SERINFO; 1683 sargs.serinfo = SLPinfo; 1684 sargs.serpath = &SLPinfo->dls_serpath[0]; 1685 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1686 1687 hargs.request = RTLD_DI_SERINFO; 1688 hargs.serinfo = hintinfo; 1689 hargs.serpath = &hintinfo->dls_serpath[0]; 1690 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1691 1692 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1693 path_enumerate(p, fill_search_info, &hargs); 1694 1695 /* 1696 * Now calculate the difference between two sets, by excluding 1697 * standard paths from the full set. 1698 */ 1699 fndx = 0; 1700 fcount = 0; 1701 filtered_path = xmalloc(hdr.dirlistlen + 1); 1702 hintpath = &hintinfo->dls_serpath[0]; 1703 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1704 skip = false; 1705 SLPpath = &SLPinfo->dls_serpath[0]; 1706 /* 1707 * Check each standard path against current. 1708 */ 1709 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1710 /* matched, skip the path */ 1711 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1712 skip = true; 1713 break; 1714 } 1715 } 1716 if (skip) 1717 continue; 1718 /* 1719 * Not matched against any standard path, add the path 1720 * to result. Separate consequtive paths with ':'. 1721 */ 1722 if (fcount > 0) { 1723 filtered_path[fndx] = ':'; 1724 fndx++; 1725 } 1726 fcount++; 1727 flen = strlen(hintpath->dls_name); 1728 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1729 fndx += flen; 1730 } 1731 filtered_path[fndx] = '\0'; 1732 1733 free(SLPinfo); 1734 free(hintinfo); 1735 1736 filt_ret: 1737 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1738 } 1739 1740 static void 1741 init_dag(Obj_Entry *root) 1742 { 1743 const Needed_Entry *needed; 1744 const Objlist_Entry *elm; 1745 DoneList donelist; 1746 1747 if (root->dag_inited) 1748 return; 1749 donelist_init(&donelist); 1750 1751 /* Root object belongs to own DAG. */ 1752 objlist_push_tail(&root->dldags, root); 1753 objlist_push_tail(&root->dagmembers, root); 1754 donelist_check(&donelist, root); 1755 1756 /* 1757 * Add dependencies of root object to DAG in breadth order 1758 * by exploiting the fact that each new object get added 1759 * to the tail of the dagmembers list. 1760 */ 1761 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1762 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1763 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1764 continue; 1765 objlist_push_tail(&needed->obj->dldags, root); 1766 objlist_push_tail(&root->dagmembers, needed->obj); 1767 } 1768 } 1769 root->dag_inited = true; 1770 } 1771 1772 static void 1773 process_nodelete(Obj_Entry *root) 1774 { 1775 const Objlist_Entry *elm; 1776 1777 /* 1778 * Walk over object DAG and process every dependent object that 1779 * is marked as DF_1_NODELETE. They need to grow their own DAG, 1780 * which then should have its reference upped separately. 1781 */ 1782 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1783 if (elm->obj != NULL && elm->obj->z_nodelete && 1784 !elm->obj->ref_nodel) { 1785 dbg("obj %s nodelete", elm->obj->path); 1786 init_dag(elm->obj); 1787 ref_dag(elm->obj); 1788 elm->obj->ref_nodel = true; 1789 } 1790 } 1791 } 1792 /* 1793 * Initialize the dynamic linker. The argument is the address at which 1794 * the dynamic linker has been mapped into memory. The primary task of 1795 * this function is to relocate the dynamic linker. 1796 */ 1797 static void 1798 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 1799 { 1800 Obj_Entry objtmp; /* Temporary rtld object */ 1801 const Elf_Dyn *dyn_rpath; 1802 const Elf_Dyn *dyn_soname; 1803 const Elf_Dyn *dyn_runpath; 1804 1805 #ifdef RTLD_INIT_PAGESIZES_EARLY 1806 /* The page size is required by the dynamic memory allocator. */ 1807 init_pagesizes(aux_info); 1808 #endif 1809 1810 /* 1811 * Conjure up an Obj_Entry structure for the dynamic linker. 1812 * 1813 * The "path" member can't be initialized yet because string constants 1814 * cannot yet be accessed. Below we will set it correctly. 1815 */ 1816 memset(&objtmp, 0, sizeof(objtmp)); 1817 objtmp.path = NULL; 1818 objtmp.rtld = true; 1819 objtmp.mapbase = mapbase; 1820 #ifdef PIC 1821 objtmp.relocbase = mapbase; 1822 #endif 1823 if (RTLD_IS_DYNAMIC()) { 1824 objtmp.dynamic = rtld_dynamic(&objtmp); 1825 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 1826 assert(objtmp.needed == NULL); 1827 #if !defined(__mips__) 1828 /* MIPS has a bogus DT_TEXTREL. */ 1829 assert(!objtmp.textrel); 1830 #endif 1831 1832 /* 1833 * Temporarily put the dynamic linker entry into the object list, so 1834 * that symbols can be found. 1835 */ 1836 1837 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 1838 } 1839 1840 /* Initialize the object list. */ 1841 obj_tail = &obj_list; 1842 1843 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1844 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1845 1846 #ifndef RTLD_INIT_PAGESIZES_EARLY 1847 /* The page size is required by the dynamic memory allocator. */ 1848 init_pagesizes(aux_info); 1849 #endif 1850 1851 if (aux_info[AT_OSRELDATE] != NULL) 1852 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 1853 1854 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 1855 1856 /* Replace the path with a dynamically allocated copy. */ 1857 obj_rtld.path = xstrdup(PATH_RTLD); 1858 1859 r_debug.r_brk = r_debug_state; 1860 r_debug.r_state = RT_CONSISTENT; 1861 } 1862 1863 /* 1864 * Retrieve the array of supported page sizes. The kernel provides the page 1865 * sizes in increasing order. 1866 */ 1867 static void 1868 init_pagesizes(Elf_Auxinfo **aux_info) 1869 { 1870 static size_t psa[MAXPAGESIZES]; 1871 int mib[2]; 1872 size_t len, size; 1873 1874 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 1875 NULL) { 1876 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 1877 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 1878 } else { 1879 len = 2; 1880 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 1881 size = sizeof(psa); 1882 else { 1883 /* As a fallback, retrieve the base page size. */ 1884 size = sizeof(psa[0]); 1885 if (aux_info[AT_PAGESZ] != NULL) { 1886 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 1887 goto psa_filled; 1888 } else { 1889 mib[0] = CTL_HW; 1890 mib[1] = HW_PAGESIZE; 1891 len = 2; 1892 } 1893 } 1894 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 1895 _rtld_error("sysctl for hw.pagesize(s) failed"); 1896 die(); 1897 } 1898 psa_filled: 1899 pagesizes = psa; 1900 } 1901 npagesizes = size / sizeof(pagesizes[0]); 1902 /* Discard any invalid entries at the end of the array. */ 1903 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 1904 npagesizes--; 1905 } 1906 1907 /* 1908 * Add the init functions from a needed object list (and its recursive 1909 * needed objects) to "list". This is not used directly; it is a helper 1910 * function for initlist_add_objects(). The write lock must be held 1911 * when this function is called. 1912 */ 1913 static void 1914 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 1915 { 1916 /* Recursively process the successor needed objects. */ 1917 if (needed->next != NULL) 1918 initlist_add_neededs(needed->next, list); 1919 1920 /* Process the current needed object. */ 1921 if (needed->obj != NULL) 1922 initlist_add_objects(needed->obj, &needed->obj->next, list); 1923 } 1924 1925 /* 1926 * Scan all of the DAGs rooted in the range of objects from "obj" to 1927 * "tail" and add their init functions to "list". This recurses over 1928 * the DAGs and ensure the proper init ordering such that each object's 1929 * needed libraries are initialized before the object itself. At the 1930 * same time, this function adds the objects to the global finalization 1931 * list "list_fini" in the opposite order. The write lock must be 1932 * held when this function is called. 1933 */ 1934 static void 1935 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list) 1936 { 1937 1938 if (obj->init_scanned || obj->init_done) 1939 return; 1940 obj->init_scanned = true; 1941 1942 /* Recursively process the successor objects. */ 1943 if (&obj->next != tail) 1944 initlist_add_objects(obj->next, tail, list); 1945 1946 /* Recursively process the needed objects. */ 1947 if (obj->needed != NULL) 1948 initlist_add_neededs(obj->needed, list); 1949 if (obj->needed_filtees != NULL) 1950 initlist_add_neededs(obj->needed_filtees, list); 1951 if (obj->needed_aux_filtees != NULL) 1952 initlist_add_neededs(obj->needed_aux_filtees, list); 1953 1954 /* Add the object to the init list. */ 1955 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL || 1956 obj->init_array != (Elf_Addr)NULL) 1957 objlist_push_tail(list, obj); 1958 1959 /* Add the object to the global fini list in the reverse order. */ 1960 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 1961 && !obj->on_fini_list) { 1962 objlist_push_head(&list_fini, obj); 1963 obj->on_fini_list = true; 1964 } 1965 } 1966 1967 #ifndef FPTR_TARGET 1968 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 1969 #endif 1970 1971 static void 1972 free_needed_filtees(Needed_Entry *n) 1973 { 1974 Needed_Entry *needed, *needed1; 1975 1976 for (needed = n; needed != NULL; needed = needed->next) { 1977 if (needed->obj != NULL) { 1978 dlclose(needed->obj); 1979 needed->obj = NULL; 1980 } 1981 } 1982 for (needed = n; needed != NULL; needed = needed1) { 1983 needed1 = needed->next; 1984 free(needed); 1985 } 1986 } 1987 1988 static void 1989 unload_filtees(Obj_Entry *obj) 1990 { 1991 1992 free_needed_filtees(obj->needed_filtees); 1993 obj->needed_filtees = NULL; 1994 free_needed_filtees(obj->needed_aux_filtees); 1995 obj->needed_aux_filtees = NULL; 1996 obj->filtees_loaded = false; 1997 } 1998 1999 static void 2000 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2001 RtldLockState *lockstate) 2002 { 2003 2004 for (; needed != NULL; needed = needed->next) { 2005 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2006 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2007 RTLD_LOCAL, lockstate); 2008 } 2009 } 2010 2011 static void 2012 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2013 { 2014 2015 lock_restart_for_upgrade(lockstate); 2016 if (!obj->filtees_loaded) { 2017 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2018 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2019 obj->filtees_loaded = true; 2020 } 2021 } 2022 2023 static int 2024 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2025 { 2026 Obj_Entry *obj1; 2027 2028 for (; needed != NULL; needed = needed->next) { 2029 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2030 flags & ~RTLD_LO_NOLOAD); 2031 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2032 return (-1); 2033 } 2034 return (0); 2035 } 2036 2037 /* 2038 * Given a shared object, traverse its list of needed objects, and load 2039 * each of them. Returns 0 on success. Generates an error message and 2040 * returns -1 on failure. 2041 */ 2042 static int 2043 load_needed_objects(Obj_Entry *first, int flags) 2044 { 2045 Obj_Entry *obj; 2046 2047 for (obj = first; obj != NULL; obj = obj->next) { 2048 if (process_needed(obj, obj->needed, flags) == -1) 2049 return (-1); 2050 } 2051 return (0); 2052 } 2053 2054 static int 2055 load_preload_objects(void) 2056 { 2057 char *p = ld_preload; 2058 Obj_Entry *obj; 2059 static const char delim[] = " \t:;"; 2060 2061 if (p == NULL) 2062 return 0; 2063 2064 p += strspn(p, delim); 2065 while (*p != '\0') { 2066 size_t len = strcspn(p, delim); 2067 char savech; 2068 2069 savech = p[len]; 2070 p[len] = '\0'; 2071 obj = load_object(p, -1, NULL, 0); 2072 if (obj == NULL) 2073 return -1; /* XXX - cleanup */ 2074 obj->z_interpose = true; 2075 p[len] = savech; 2076 p += len; 2077 p += strspn(p, delim); 2078 } 2079 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2080 return 0; 2081 } 2082 2083 static const char * 2084 printable_path(const char *path) 2085 { 2086 2087 return (path == NULL ? "<unknown>" : path); 2088 } 2089 2090 /* 2091 * Load a shared object into memory, if it is not already loaded. The 2092 * object may be specified by name or by user-supplied file descriptor 2093 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2094 * duplicate is. 2095 * 2096 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2097 * on failure. 2098 */ 2099 static Obj_Entry * 2100 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2101 { 2102 Obj_Entry *obj; 2103 int fd; 2104 struct stat sb; 2105 char *path; 2106 2107 fd = -1; 2108 if (name != NULL) { 2109 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 2110 if (object_match_name(obj, name)) 2111 return (obj); 2112 } 2113 2114 path = find_library(name, refobj, &fd); 2115 if (path == NULL) 2116 return (NULL); 2117 } else 2118 path = NULL; 2119 2120 if (fd >= 0) { 2121 /* 2122 * search_library_pathfds() opens a fresh file descriptor for the 2123 * library, so there is no need to dup(). 2124 */ 2125 } else if (fd_u == -1) { 2126 /* 2127 * If we didn't find a match by pathname, or the name is not 2128 * supplied, open the file and check again by device and inode. 2129 * This avoids false mismatches caused by multiple links or ".." 2130 * in pathnames. 2131 * 2132 * To avoid a race, we open the file and use fstat() rather than 2133 * using stat(). 2134 */ 2135 if ((fd = open(path, O_RDONLY | O_CLOEXEC)) == -1) { 2136 _rtld_error("Cannot open \"%s\"", path); 2137 free(path); 2138 return (NULL); 2139 } 2140 } else { 2141 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2142 if (fd == -1) { 2143 _rtld_error("Cannot dup fd"); 2144 free(path); 2145 return (NULL); 2146 } 2147 } 2148 if (fstat(fd, &sb) == -1) { 2149 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2150 close(fd); 2151 free(path); 2152 return NULL; 2153 } 2154 for (obj = obj_list->next; obj != NULL; obj = obj->next) 2155 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2156 break; 2157 if (obj != NULL && name != NULL) { 2158 object_add_name(obj, name); 2159 free(path); 2160 close(fd); 2161 return obj; 2162 } 2163 if (flags & RTLD_LO_NOLOAD) { 2164 free(path); 2165 close(fd); 2166 return (NULL); 2167 } 2168 2169 /* First use of this object, so we must map it in */ 2170 obj = do_load_object(fd, name, path, &sb, flags); 2171 if (obj == NULL) 2172 free(path); 2173 close(fd); 2174 2175 return obj; 2176 } 2177 2178 static Obj_Entry * 2179 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2180 int flags) 2181 { 2182 Obj_Entry *obj; 2183 struct statfs fs; 2184 2185 /* 2186 * but first, make sure that environment variables haven't been 2187 * used to circumvent the noexec flag on a filesystem. 2188 */ 2189 if (dangerous_ld_env) { 2190 if (fstatfs(fd, &fs) != 0) { 2191 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2192 return NULL; 2193 } 2194 if (fs.f_flags & MNT_NOEXEC) { 2195 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 2196 return NULL; 2197 } 2198 } 2199 dbg("loading \"%s\"", printable_path(path)); 2200 obj = map_object(fd, printable_path(path), sbp); 2201 if (obj == NULL) 2202 return NULL; 2203 2204 /* 2205 * If DT_SONAME is present in the object, digest_dynamic2 already 2206 * added it to the object names. 2207 */ 2208 if (name != NULL) 2209 object_add_name(obj, name); 2210 obj->path = path; 2211 digest_dynamic(obj, 0); 2212 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2213 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2214 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2215 RTLD_LO_DLOPEN) { 2216 dbg("refusing to load non-loadable \"%s\"", obj->path); 2217 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2218 munmap(obj->mapbase, obj->mapsize); 2219 obj_free(obj); 2220 return (NULL); 2221 } 2222 2223 *obj_tail = obj; 2224 obj_tail = &obj->next; 2225 obj_count++; 2226 obj_loads++; 2227 linkmap_add(obj); /* for GDB & dlinfo() */ 2228 max_stack_flags |= obj->stack_flags; 2229 2230 dbg(" %p .. %p: %s", obj->mapbase, 2231 obj->mapbase + obj->mapsize - 1, obj->path); 2232 if (obj->textrel) 2233 dbg(" WARNING: %s has impure text", obj->path); 2234 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2235 obj->path); 2236 2237 return obj; 2238 } 2239 2240 static Obj_Entry * 2241 obj_from_addr(const void *addr) 2242 { 2243 Obj_Entry *obj; 2244 2245 for (obj = obj_list; obj != NULL; obj = obj->next) { 2246 if (addr < (void *) obj->mapbase) 2247 continue; 2248 if (addr < (void *) (obj->mapbase + obj->mapsize)) 2249 return obj; 2250 } 2251 return NULL; 2252 } 2253 2254 static void 2255 preinit_main(void) 2256 { 2257 Elf_Addr *preinit_addr; 2258 int index; 2259 2260 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2261 if (preinit_addr == NULL) 2262 return; 2263 2264 for (index = 0; index < obj_main->preinit_array_num; index++) { 2265 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2266 dbg("calling preinit function for %s at %p", obj_main->path, 2267 (void *)preinit_addr[index]); 2268 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2269 0, 0, obj_main->path); 2270 call_init_pointer(obj_main, preinit_addr[index]); 2271 } 2272 } 2273 } 2274 2275 /* 2276 * Call the finalization functions for each of the objects in "list" 2277 * belonging to the DAG of "root" and referenced once. If NULL "root" 2278 * is specified, every finalization function will be called regardless 2279 * of the reference count and the list elements won't be freed. All of 2280 * the objects are expected to have non-NULL fini functions. 2281 */ 2282 static void 2283 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2284 { 2285 Objlist_Entry *elm; 2286 char *saved_msg; 2287 Elf_Addr *fini_addr; 2288 int index; 2289 2290 assert(root == NULL || root->refcount == 1); 2291 2292 /* 2293 * Preserve the current error message since a fini function might 2294 * call into the dynamic linker and overwrite it. 2295 */ 2296 saved_msg = errmsg_save(); 2297 do { 2298 STAILQ_FOREACH(elm, list, link) { 2299 if (root != NULL && (elm->obj->refcount != 1 || 2300 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2301 continue; 2302 /* Remove object from fini list to prevent recursive invocation. */ 2303 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2304 /* 2305 * XXX: If a dlopen() call references an object while the 2306 * fini function is in progress, we might end up trying to 2307 * unload the referenced object in dlclose() or the object 2308 * won't be unloaded although its fini function has been 2309 * called. 2310 */ 2311 lock_release(rtld_bind_lock, lockstate); 2312 2313 /* 2314 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2315 * When this happens, DT_FINI_ARRAY is processed first. 2316 */ 2317 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2318 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2319 for (index = elm->obj->fini_array_num - 1; index >= 0; 2320 index--) { 2321 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2322 dbg("calling fini function for %s at %p", 2323 elm->obj->path, (void *)fini_addr[index]); 2324 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2325 (void *)fini_addr[index], 0, 0, elm->obj->path); 2326 call_initfini_pointer(elm->obj, fini_addr[index]); 2327 } 2328 } 2329 } 2330 if (elm->obj->fini != (Elf_Addr)NULL) { 2331 dbg("calling fini function for %s at %p", elm->obj->path, 2332 (void *)elm->obj->fini); 2333 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2334 0, 0, elm->obj->path); 2335 call_initfini_pointer(elm->obj, elm->obj->fini); 2336 } 2337 wlock_acquire(rtld_bind_lock, lockstate); 2338 /* No need to free anything if process is going down. */ 2339 if (root != NULL) 2340 free(elm); 2341 /* 2342 * We must restart the list traversal after every fini call 2343 * because a dlclose() call from the fini function or from 2344 * another thread might have modified the reference counts. 2345 */ 2346 break; 2347 } 2348 } while (elm != NULL); 2349 errmsg_restore(saved_msg); 2350 } 2351 2352 /* 2353 * Call the initialization functions for each of the objects in 2354 * "list". All of the objects are expected to have non-NULL init 2355 * functions. 2356 */ 2357 static void 2358 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2359 { 2360 Objlist_Entry *elm; 2361 Obj_Entry *obj; 2362 char *saved_msg; 2363 Elf_Addr *init_addr; 2364 int index; 2365 2366 /* 2367 * Clean init_scanned flag so that objects can be rechecked and 2368 * possibly initialized earlier if any of vectors called below 2369 * cause the change by using dlopen. 2370 */ 2371 for (obj = obj_list; obj != NULL; obj = obj->next) 2372 obj->init_scanned = false; 2373 2374 /* 2375 * Preserve the current error message since an init function might 2376 * call into the dynamic linker and overwrite it. 2377 */ 2378 saved_msg = errmsg_save(); 2379 STAILQ_FOREACH(elm, list, link) { 2380 if (elm->obj->init_done) /* Initialized early. */ 2381 continue; 2382 /* 2383 * Race: other thread might try to use this object before current 2384 * one completes the initilization. Not much can be done here 2385 * without better locking. 2386 */ 2387 elm->obj->init_done = true; 2388 lock_release(rtld_bind_lock, lockstate); 2389 2390 /* 2391 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2392 * When this happens, DT_INIT is processed first. 2393 */ 2394 if (elm->obj->init != (Elf_Addr)NULL) { 2395 dbg("calling init function for %s at %p", elm->obj->path, 2396 (void *)elm->obj->init); 2397 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2398 0, 0, elm->obj->path); 2399 call_initfini_pointer(elm->obj, elm->obj->init); 2400 } 2401 init_addr = (Elf_Addr *)elm->obj->init_array; 2402 if (init_addr != NULL) { 2403 for (index = 0; index < elm->obj->init_array_num; index++) { 2404 if (init_addr[index] != 0 && init_addr[index] != 1) { 2405 dbg("calling init function for %s at %p", elm->obj->path, 2406 (void *)init_addr[index]); 2407 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2408 (void *)init_addr[index], 0, 0, elm->obj->path); 2409 call_init_pointer(elm->obj, init_addr[index]); 2410 } 2411 } 2412 } 2413 wlock_acquire(rtld_bind_lock, lockstate); 2414 } 2415 errmsg_restore(saved_msg); 2416 } 2417 2418 static void 2419 objlist_clear(Objlist *list) 2420 { 2421 Objlist_Entry *elm; 2422 2423 while (!STAILQ_EMPTY(list)) { 2424 elm = STAILQ_FIRST(list); 2425 STAILQ_REMOVE_HEAD(list, link); 2426 free(elm); 2427 } 2428 } 2429 2430 static Objlist_Entry * 2431 objlist_find(Objlist *list, const Obj_Entry *obj) 2432 { 2433 Objlist_Entry *elm; 2434 2435 STAILQ_FOREACH(elm, list, link) 2436 if (elm->obj == obj) 2437 return elm; 2438 return NULL; 2439 } 2440 2441 static void 2442 objlist_init(Objlist *list) 2443 { 2444 STAILQ_INIT(list); 2445 } 2446 2447 static void 2448 objlist_push_head(Objlist *list, Obj_Entry *obj) 2449 { 2450 Objlist_Entry *elm; 2451 2452 elm = NEW(Objlist_Entry); 2453 elm->obj = obj; 2454 STAILQ_INSERT_HEAD(list, elm, link); 2455 } 2456 2457 static void 2458 objlist_push_tail(Objlist *list, Obj_Entry *obj) 2459 { 2460 Objlist_Entry *elm; 2461 2462 elm = NEW(Objlist_Entry); 2463 elm->obj = obj; 2464 STAILQ_INSERT_TAIL(list, elm, link); 2465 } 2466 2467 static void 2468 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2469 { 2470 Objlist_Entry *elm, *listelm; 2471 2472 STAILQ_FOREACH(listelm, list, link) { 2473 if (listelm->obj == listobj) 2474 break; 2475 } 2476 elm = NEW(Objlist_Entry); 2477 elm->obj = obj; 2478 if (listelm != NULL) 2479 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2480 else 2481 STAILQ_INSERT_TAIL(list, elm, link); 2482 } 2483 2484 static void 2485 objlist_remove(Objlist *list, Obj_Entry *obj) 2486 { 2487 Objlist_Entry *elm; 2488 2489 if ((elm = objlist_find(list, obj)) != NULL) { 2490 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2491 free(elm); 2492 } 2493 } 2494 2495 /* 2496 * Relocate dag rooted in the specified object. 2497 * Returns 0 on success, or -1 on failure. 2498 */ 2499 2500 static int 2501 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2502 int flags, RtldLockState *lockstate) 2503 { 2504 Objlist_Entry *elm; 2505 int error; 2506 2507 error = 0; 2508 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2509 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2510 lockstate); 2511 if (error == -1) 2512 break; 2513 } 2514 return (error); 2515 } 2516 2517 /* 2518 * Relocate single object. 2519 * Returns 0 on success, or -1 on failure. 2520 */ 2521 static int 2522 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2523 int flags, RtldLockState *lockstate) 2524 { 2525 2526 if (obj->relocated) 2527 return (0); 2528 obj->relocated = true; 2529 if (obj != rtldobj) 2530 dbg("relocating \"%s\"", obj->path); 2531 2532 if (obj->symtab == NULL || obj->strtab == NULL || 2533 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2534 _rtld_error("%s: Shared object has no run-time symbol table", 2535 obj->path); 2536 return (-1); 2537 } 2538 2539 if (obj->textrel) { 2540 /* There are relocations to the write-protected text segment. */ 2541 if (mprotect(obj->mapbase, obj->textsize, 2542 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) { 2543 _rtld_error("%s: Cannot write-enable text segment: %s", 2544 obj->path, rtld_strerror(errno)); 2545 return (-1); 2546 } 2547 } 2548 2549 /* Process the non-PLT non-IFUNC relocations. */ 2550 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2551 return (-1); 2552 2553 if (obj->textrel) { /* Re-protected the text segment. */ 2554 if (mprotect(obj->mapbase, obj->textsize, 2555 PROT_READ|PROT_EXEC) == -1) { 2556 _rtld_error("%s: Cannot write-protect text segment: %s", 2557 obj->path, rtld_strerror(errno)); 2558 return (-1); 2559 } 2560 } 2561 2562 /* Set the special PLT or GOT entries. */ 2563 init_pltgot(obj); 2564 2565 /* Process the PLT relocations. */ 2566 if (reloc_plt(obj) == -1) 2567 return (-1); 2568 /* Relocate the jump slots if we are doing immediate binding. */ 2569 if (obj->bind_now || bind_now) 2570 if (reloc_jmpslots(obj, flags, lockstate) == -1) 2571 return (-1); 2572 2573 /* 2574 * Process the non-PLT IFUNC relocations. The relocations are 2575 * processed in two phases, because IFUNC resolvers may 2576 * reference other symbols, which must be readily processed 2577 * before resolvers are called. 2578 */ 2579 if (obj->non_plt_gnu_ifunc && 2580 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate)) 2581 return (-1); 2582 2583 if (obj->relro_size > 0) { 2584 if (mprotect(obj->relro_page, obj->relro_size, 2585 PROT_READ) == -1) { 2586 _rtld_error("%s: Cannot enforce relro protection: %s", 2587 obj->path, rtld_strerror(errno)); 2588 return (-1); 2589 } 2590 } 2591 2592 /* 2593 * Set up the magic number and version in the Obj_Entry. These 2594 * were checked in the crt1.o from the original ElfKit, so we 2595 * set them for backward compatibility. 2596 */ 2597 obj->magic = RTLD_MAGIC; 2598 obj->version = RTLD_VERSION; 2599 2600 return (0); 2601 } 2602 2603 /* 2604 * Relocate newly-loaded shared objects. The argument is a pointer to 2605 * the Obj_Entry for the first such object. All objects from the first 2606 * to the end of the list of objects are relocated. Returns 0 on success, 2607 * or -1 on failure. 2608 */ 2609 static int 2610 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2611 int flags, RtldLockState *lockstate) 2612 { 2613 Obj_Entry *obj; 2614 int error; 2615 2616 for (error = 0, obj = first; obj != NULL; obj = obj->next) { 2617 error = relocate_object(obj, bind_now, rtldobj, flags, 2618 lockstate); 2619 if (error == -1) 2620 break; 2621 } 2622 return (error); 2623 } 2624 2625 /* 2626 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2627 * referencing STT_GNU_IFUNC symbols is postponed till the other 2628 * relocations are done. The indirect functions specified as 2629 * ifunc are allowed to call other symbols, so we need to have 2630 * objects relocated before asking for resolution from indirects. 2631 * 2632 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2633 * instead of the usual lazy handling of PLT slots. It is 2634 * consistent with how GNU does it. 2635 */ 2636 static int 2637 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2638 RtldLockState *lockstate) 2639 { 2640 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2641 return (-1); 2642 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2643 reloc_gnu_ifunc(obj, flags, lockstate) == -1) 2644 return (-1); 2645 return (0); 2646 } 2647 2648 static int 2649 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags, 2650 RtldLockState *lockstate) 2651 { 2652 Obj_Entry *obj; 2653 2654 for (obj = first; obj != NULL; obj = obj->next) { 2655 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1) 2656 return (-1); 2657 } 2658 return (0); 2659 } 2660 2661 static int 2662 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2663 RtldLockState *lockstate) 2664 { 2665 Objlist_Entry *elm; 2666 2667 STAILQ_FOREACH(elm, list, link) { 2668 if (resolve_object_ifunc(elm->obj, bind_now, flags, 2669 lockstate) == -1) 2670 return (-1); 2671 } 2672 return (0); 2673 } 2674 2675 /* 2676 * Cleanup procedure. It will be called (by the atexit mechanism) just 2677 * before the process exits. 2678 */ 2679 static void 2680 rtld_exit(void) 2681 { 2682 RtldLockState lockstate; 2683 2684 wlock_acquire(rtld_bind_lock, &lockstate); 2685 dbg("rtld_exit()"); 2686 objlist_call_fini(&list_fini, NULL, &lockstate); 2687 /* No need to remove the items from the list, since we are exiting. */ 2688 if (!libmap_disable) 2689 lm_fini(); 2690 lock_release(rtld_bind_lock, &lockstate); 2691 } 2692 2693 /* 2694 * Iterate over a search path, translate each element, and invoke the 2695 * callback on the result. 2696 */ 2697 static void * 2698 path_enumerate(const char *path, path_enum_proc callback, void *arg) 2699 { 2700 const char *trans; 2701 if (path == NULL) 2702 return (NULL); 2703 2704 path += strspn(path, ":;"); 2705 while (*path != '\0') { 2706 size_t len; 2707 char *res; 2708 2709 len = strcspn(path, ":;"); 2710 trans = lm_findn(NULL, path, len); 2711 if (trans) 2712 res = callback(trans, strlen(trans), arg); 2713 else 2714 res = callback(path, len, arg); 2715 2716 if (res != NULL) 2717 return (res); 2718 2719 path += len; 2720 path += strspn(path, ":;"); 2721 } 2722 2723 return (NULL); 2724 } 2725 2726 struct try_library_args { 2727 const char *name; 2728 size_t namelen; 2729 char *buffer; 2730 size_t buflen; 2731 }; 2732 2733 static void * 2734 try_library_path(const char *dir, size_t dirlen, void *param) 2735 { 2736 struct try_library_args *arg; 2737 2738 arg = param; 2739 if (*dir == '/' || trust) { 2740 char *pathname; 2741 2742 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 2743 return (NULL); 2744 2745 pathname = arg->buffer; 2746 strncpy(pathname, dir, dirlen); 2747 pathname[dirlen] = '/'; 2748 strcpy(pathname + dirlen + 1, arg->name); 2749 2750 dbg(" Trying \"%s\"", pathname); 2751 if (access(pathname, F_OK) == 0) { /* We found it */ 2752 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 2753 strcpy(pathname, arg->buffer); 2754 return (pathname); 2755 } 2756 } 2757 return (NULL); 2758 } 2759 2760 static char * 2761 search_library_path(const char *name, const char *path) 2762 { 2763 char *p; 2764 struct try_library_args arg; 2765 2766 if (path == NULL) 2767 return NULL; 2768 2769 arg.name = name; 2770 arg.namelen = strlen(name); 2771 arg.buffer = xmalloc(PATH_MAX); 2772 arg.buflen = PATH_MAX; 2773 2774 p = path_enumerate(path, try_library_path, &arg); 2775 2776 free(arg.buffer); 2777 2778 return (p); 2779 } 2780 2781 2782 /* 2783 * Finds the library with the given name using the directory descriptors 2784 * listed in the LD_LIBRARY_PATH_FDS environment variable. 2785 * 2786 * Returns a freshly-opened close-on-exec file descriptor for the library, 2787 * or -1 if the library cannot be found. 2788 */ 2789 static char * 2790 search_library_pathfds(const char *name, const char *path, int *fdp) 2791 { 2792 char *envcopy, *fdstr, *found, *last_token; 2793 size_t len; 2794 int dirfd, fd; 2795 2796 dbg("%s('%s', '%s', fdp)", __func__, name, path); 2797 2798 /* Don't load from user-specified libdirs into setuid binaries. */ 2799 if (!trust) 2800 return (NULL); 2801 2802 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 2803 if (path == NULL) 2804 return (NULL); 2805 2806 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 2807 if (name[0] == '/') { 2808 dbg("Absolute path (%s) passed to %s", name, __func__); 2809 return (NULL); 2810 } 2811 2812 /* 2813 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 2814 * copy of the path, as strtok_r rewrites separator tokens 2815 * with '\0'. 2816 */ 2817 found = NULL; 2818 envcopy = xstrdup(path); 2819 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 2820 fdstr = strtok_r(NULL, ":", &last_token)) { 2821 dirfd = parse_libdir(fdstr); 2822 if (dirfd < 0) 2823 break; 2824 fd = openat(dirfd, name, O_RDONLY | O_CLOEXEC); 2825 if (fd >= 0) { 2826 *fdp = fd; 2827 len = strlen(fdstr) + strlen(name) + 3; 2828 found = xmalloc(len); 2829 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 2830 _rtld_error("error generating '%d/%s'", 2831 dirfd, name); 2832 die(); 2833 } 2834 dbg("open('%s') => %d", found, fd); 2835 break; 2836 } 2837 } 2838 free(envcopy); 2839 2840 return (found); 2841 } 2842 2843 2844 int 2845 dlclose(void *handle) 2846 { 2847 Obj_Entry *root; 2848 RtldLockState lockstate; 2849 2850 wlock_acquire(rtld_bind_lock, &lockstate); 2851 root = dlcheck(handle); 2852 if (root == NULL) { 2853 lock_release(rtld_bind_lock, &lockstate); 2854 return -1; 2855 } 2856 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 2857 root->path); 2858 2859 /* Unreference the object and its dependencies. */ 2860 root->dl_refcount--; 2861 2862 if (root->refcount == 1) { 2863 /* 2864 * The object will be no longer referenced, so we must unload it. 2865 * First, call the fini functions. 2866 */ 2867 objlist_call_fini(&list_fini, root, &lockstate); 2868 2869 unref_dag(root); 2870 2871 /* Finish cleaning up the newly-unreferenced objects. */ 2872 GDB_STATE(RT_DELETE,&root->linkmap); 2873 unload_object(root); 2874 GDB_STATE(RT_CONSISTENT,NULL); 2875 } else 2876 unref_dag(root); 2877 2878 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 2879 lock_release(rtld_bind_lock, &lockstate); 2880 return 0; 2881 } 2882 2883 char * 2884 dlerror(void) 2885 { 2886 char *msg = error_message; 2887 error_message = NULL; 2888 return msg; 2889 } 2890 2891 /* 2892 * This function is deprecated and has no effect. 2893 */ 2894 void 2895 dllockinit(void *context, 2896 void *(*lock_create)(void *context), 2897 void (*rlock_acquire)(void *lock), 2898 void (*wlock_acquire)(void *lock), 2899 void (*lock_release)(void *lock), 2900 void (*lock_destroy)(void *lock), 2901 void (*context_destroy)(void *context)) 2902 { 2903 static void *cur_context; 2904 static void (*cur_context_destroy)(void *); 2905 2906 /* Just destroy the context from the previous call, if necessary. */ 2907 if (cur_context_destroy != NULL) 2908 cur_context_destroy(cur_context); 2909 cur_context = context; 2910 cur_context_destroy = context_destroy; 2911 } 2912 2913 void * 2914 dlopen(const char *name, int mode) 2915 { 2916 2917 return (rtld_dlopen(name, -1, mode)); 2918 } 2919 2920 void * 2921 fdlopen(int fd, int mode) 2922 { 2923 2924 return (rtld_dlopen(NULL, fd, mode)); 2925 } 2926 2927 static void * 2928 rtld_dlopen(const char *name, int fd, int mode) 2929 { 2930 RtldLockState lockstate; 2931 int lo_flags; 2932 2933 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 2934 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 2935 if (ld_tracing != NULL) { 2936 rlock_acquire(rtld_bind_lock, &lockstate); 2937 if (sigsetjmp(lockstate.env, 0) != 0) 2938 lock_upgrade(rtld_bind_lock, &lockstate); 2939 environ = (char **)*get_program_var_addr("environ", &lockstate); 2940 lock_release(rtld_bind_lock, &lockstate); 2941 } 2942 lo_flags = RTLD_LO_DLOPEN; 2943 if (mode & RTLD_NODELETE) 2944 lo_flags |= RTLD_LO_NODELETE; 2945 if (mode & RTLD_NOLOAD) 2946 lo_flags |= RTLD_LO_NOLOAD; 2947 if (ld_tracing != NULL) 2948 lo_flags |= RTLD_LO_TRACE; 2949 2950 return (dlopen_object(name, fd, obj_main, lo_flags, 2951 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 2952 } 2953 2954 static void 2955 dlopen_cleanup(Obj_Entry *obj) 2956 { 2957 2958 obj->dl_refcount--; 2959 unref_dag(obj); 2960 if (obj->refcount == 0) 2961 unload_object(obj); 2962 } 2963 2964 static Obj_Entry * 2965 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 2966 int mode, RtldLockState *lockstate) 2967 { 2968 Obj_Entry **old_obj_tail; 2969 Obj_Entry *obj; 2970 Objlist initlist; 2971 RtldLockState mlockstate; 2972 int result; 2973 2974 objlist_init(&initlist); 2975 2976 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 2977 wlock_acquire(rtld_bind_lock, &mlockstate); 2978 lockstate = &mlockstate; 2979 } 2980 GDB_STATE(RT_ADD,NULL); 2981 2982 old_obj_tail = obj_tail; 2983 obj = NULL; 2984 if (name == NULL && fd == -1) { 2985 obj = obj_main; 2986 obj->refcount++; 2987 } else { 2988 obj = load_object(name, fd, refobj, lo_flags); 2989 } 2990 2991 if (obj) { 2992 obj->dl_refcount++; 2993 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 2994 objlist_push_tail(&list_global, obj); 2995 if (*old_obj_tail != NULL) { /* We loaded something new. */ 2996 assert(*old_obj_tail == obj); 2997 result = load_needed_objects(obj, 2998 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 2999 init_dag(obj); 3000 ref_dag(obj); 3001 if (result != -1) 3002 result = rtld_verify_versions(&obj->dagmembers); 3003 if (result != -1 && ld_tracing) 3004 goto trace; 3005 if (result == -1 || relocate_object_dag(obj, 3006 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3007 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3008 lockstate) == -1) { 3009 dlopen_cleanup(obj); 3010 obj = NULL; 3011 } else if (lo_flags & RTLD_LO_EARLY) { 3012 /* 3013 * Do not call the init functions for early loaded 3014 * filtees. The image is still not initialized enough 3015 * for them to work. 3016 * 3017 * Our object is found by the global object list and 3018 * will be ordered among all init calls done right 3019 * before transferring control to main. 3020 */ 3021 } else { 3022 /* Make list of init functions to call. */ 3023 initlist_add_objects(obj, &obj->next, &initlist); 3024 } 3025 /* 3026 * Process all no_delete objects here, given them own 3027 * DAGs to prevent their dependencies from being unloaded. 3028 * This has to be done after we have loaded all of the 3029 * dependencies, so that we do not miss any. 3030 */ 3031 if (obj != NULL) 3032 process_nodelete(obj); 3033 } else { 3034 /* 3035 * Bump the reference counts for objects on this DAG. If 3036 * this is the first dlopen() call for the object that was 3037 * already loaded as a dependency, initialize the dag 3038 * starting at it. 3039 */ 3040 init_dag(obj); 3041 ref_dag(obj); 3042 3043 if ((lo_flags & RTLD_LO_TRACE) != 0) 3044 goto trace; 3045 } 3046 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3047 obj->z_nodelete) && !obj->ref_nodel) { 3048 dbg("obj %s nodelete", obj->path); 3049 ref_dag(obj); 3050 obj->z_nodelete = obj->ref_nodel = true; 3051 } 3052 } 3053 3054 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3055 name); 3056 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3057 3058 if (!(lo_flags & RTLD_LO_EARLY)) { 3059 map_stacks_exec(lockstate); 3060 } 3061 3062 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3063 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3064 lockstate) == -1) { 3065 objlist_clear(&initlist); 3066 dlopen_cleanup(obj); 3067 if (lockstate == &mlockstate) 3068 lock_release(rtld_bind_lock, lockstate); 3069 return (NULL); 3070 } 3071 3072 if (!(lo_flags & RTLD_LO_EARLY)) { 3073 /* Call the init functions. */ 3074 objlist_call_init(&initlist, lockstate); 3075 } 3076 objlist_clear(&initlist); 3077 if (lockstate == &mlockstate) 3078 lock_release(rtld_bind_lock, lockstate); 3079 return obj; 3080 trace: 3081 trace_loaded_objects(obj); 3082 if (lockstate == &mlockstate) 3083 lock_release(rtld_bind_lock, lockstate); 3084 exit(0); 3085 } 3086 3087 static void * 3088 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3089 int flags) 3090 { 3091 DoneList donelist; 3092 const Obj_Entry *obj, *defobj; 3093 const Elf_Sym *def; 3094 SymLook req; 3095 RtldLockState lockstate; 3096 tls_index ti; 3097 int res; 3098 3099 def = NULL; 3100 defobj = NULL; 3101 symlook_init(&req, name); 3102 req.ventry = ve; 3103 req.flags = flags | SYMLOOK_IN_PLT; 3104 req.lockstate = &lockstate; 3105 3106 rlock_acquire(rtld_bind_lock, &lockstate); 3107 if (sigsetjmp(lockstate.env, 0) != 0) 3108 lock_upgrade(rtld_bind_lock, &lockstate); 3109 if (handle == NULL || handle == RTLD_NEXT || 3110 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3111 3112 if ((obj = obj_from_addr(retaddr)) == NULL) { 3113 _rtld_error("Cannot determine caller's shared object"); 3114 lock_release(rtld_bind_lock, &lockstate); 3115 return NULL; 3116 } 3117 if (handle == NULL) { /* Just the caller's shared object. */ 3118 res = symlook_obj(&req, obj); 3119 if (res == 0) { 3120 def = req.sym_out; 3121 defobj = req.defobj_out; 3122 } 3123 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3124 handle == RTLD_SELF) { /* ... caller included */ 3125 if (handle == RTLD_NEXT) 3126 obj = obj->next; 3127 for (; obj != NULL; obj = obj->next) { 3128 res = symlook_obj(&req, obj); 3129 if (res == 0) { 3130 if (def == NULL || 3131 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3132 def = req.sym_out; 3133 defobj = req.defobj_out; 3134 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3135 break; 3136 } 3137 } 3138 } 3139 /* 3140 * Search the dynamic linker itself, and possibly resolve the 3141 * symbol from there. This is how the application links to 3142 * dynamic linker services such as dlopen. 3143 */ 3144 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3145 res = symlook_obj(&req, &obj_rtld); 3146 if (res == 0) { 3147 def = req.sym_out; 3148 defobj = req.defobj_out; 3149 } 3150 } 3151 } else { 3152 assert(handle == RTLD_DEFAULT); 3153 res = symlook_default(&req, obj); 3154 if (res == 0) { 3155 defobj = req.defobj_out; 3156 def = req.sym_out; 3157 } 3158 } 3159 } else { 3160 if ((obj = dlcheck(handle)) == NULL) { 3161 lock_release(rtld_bind_lock, &lockstate); 3162 return NULL; 3163 } 3164 3165 donelist_init(&donelist); 3166 if (obj->mainprog) { 3167 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3168 res = symlook_global(&req, &donelist); 3169 if (res == 0) { 3170 def = req.sym_out; 3171 defobj = req.defobj_out; 3172 } 3173 /* 3174 * Search the dynamic linker itself, and possibly resolve the 3175 * symbol from there. This is how the application links to 3176 * dynamic linker services such as dlopen. 3177 */ 3178 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3179 res = symlook_obj(&req, &obj_rtld); 3180 if (res == 0) { 3181 def = req.sym_out; 3182 defobj = req.defobj_out; 3183 } 3184 } 3185 } 3186 else { 3187 /* Search the whole DAG rooted at the given object. */ 3188 res = symlook_list(&req, &obj->dagmembers, &donelist); 3189 if (res == 0) { 3190 def = req.sym_out; 3191 defobj = req.defobj_out; 3192 } 3193 } 3194 } 3195 3196 if (def != NULL) { 3197 lock_release(rtld_bind_lock, &lockstate); 3198 3199 /* 3200 * The value required by the caller is derived from the value 3201 * of the symbol. this is simply the relocated value of the 3202 * symbol. 3203 */ 3204 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3205 return (make_function_pointer(def, defobj)); 3206 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3207 return (rtld_resolve_ifunc(defobj, def)); 3208 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3209 ti.ti_module = defobj->tlsindex; 3210 ti.ti_offset = def->st_value; 3211 return (__tls_get_addr(&ti)); 3212 } else 3213 return (defobj->relocbase + def->st_value); 3214 } 3215 3216 _rtld_error("Undefined symbol \"%s\"", name); 3217 lock_release(rtld_bind_lock, &lockstate); 3218 return NULL; 3219 } 3220 3221 void * 3222 dlsym(void *handle, const char *name) 3223 { 3224 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3225 SYMLOOK_DLSYM); 3226 } 3227 3228 dlfunc_t 3229 dlfunc(void *handle, const char *name) 3230 { 3231 union { 3232 void *d; 3233 dlfunc_t f; 3234 } rv; 3235 3236 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3237 SYMLOOK_DLSYM); 3238 return (rv.f); 3239 } 3240 3241 void * 3242 dlvsym(void *handle, const char *name, const char *version) 3243 { 3244 Ver_Entry ventry; 3245 3246 ventry.name = version; 3247 ventry.file = NULL; 3248 ventry.hash = elf_hash(version); 3249 ventry.flags= 0; 3250 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3251 SYMLOOK_DLSYM); 3252 } 3253 3254 int 3255 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3256 { 3257 const Obj_Entry *obj; 3258 RtldLockState lockstate; 3259 3260 rlock_acquire(rtld_bind_lock, &lockstate); 3261 obj = obj_from_addr(addr); 3262 if (obj == NULL) { 3263 _rtld_error("No shared object contains address"); 3264 lock_release(rtld_bind_lock, &lockstate); 3265 return (0); 3266 } 3267 rtld_fill_dl_phdr_info(obj, phdr_info); 3268 lock_release(rtld_bind_lock, &lockstate); 3269 return (1); 3270 } 3271 3272 int 3273 dladdr(const void *addr, Dl_info *info) 3274 { 3275 const Obj_Entry *obj; 3276 const Elf_Sym *def; 3277 void *symbol_addr; 3278 unsigned long symoffset; 3279 RtldLockState lockstate; 3280 3281 rlock_acquire(rtld_bind_lock, &lockstate); 3282 obj = obj_from_addr(addr); 3283 if (obj == NULL) { 3284 _rtld_error("No shared object contains address"); 3285 lock_release(rtld_bind_lock, &lockstate); 3286 return 0; 3287 } 3288 info->dli_fname = obj->path; 3289 info->dli_fbase = obj->mapbase; 3290 info->dli_saddr = (void *)0; 3291 info->dli_sname = NULL; 3292 3293 /* 3294 * Walk the symbol list looking for the symbol whose address is 3295 * closest to the address sent in. 3296 */ 3297 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3298 def = obj->symtab + symoffset; 3299 3300 /* 3301 * For skip the symbol if st_shndx is either SHN_UNDEF or 3302 * SHN_COMMON. 3303 */ 3304 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3305 continue; 3306 3307 /* 3308 * If the symbol is greater than the specified address, or if it 3309 * is further away from addr than the current nearest symbol, 3310 * then reject it. 3311 */ 3312 symbol_addr = obj->relocbase + def->st_value; 3313 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3314 continue; 3315 3316 /* Update our idea of the nearest symbol. */ 3317 info->dli_sname = obj->strtab + def->st_name; 3318 info->dli_saddr = symbol_addr; 3319 3320 /* Exact match? */ 3321 if (info->dli_saddr == addr) 3322 break; 3323 } 3324 lock_release(rtld_bind_lock, &lockstate); 3325 return 1; 3326 } 3327 3328 int 3329 dlinfo(void *handle, int request, void *p) 3330 { 3331 const Obj_Entry *obj; 3332 RtldLockState lockstate; 3333 int error; 3334 3335 rlock_acquire(rtld_bind_lock, &lockstate); 3336 3337 if (handle == NULL || handle == RTLD_SELF) { 3338 void *retaddr; 3339 3340 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3341 if ((obj = obj_from_addr(retaddr)) == NULL) 3342 _rtld_error("Cannot determine caller's shared object"); 3343 } else 3344 obj = dlcheck(handle); 3345 3346 if (obj == NULL) { 3347 lock_release(rtld_bind_lock, &lockstate); 3348 return (-1); 3349 } 3350 3351 error = 0; 3352 switch (request) { 3353 case RTLD_DI_LINKMAP: 3354 *((struct link_map const **)p) = &obj->linkmap; 3355 break; 3356 case RTLD_DI_ORIGIN: 3357 error = rtld_dirname(obj->path, p); 3358 break; 3359 3360 case RTLD_DI_SERINFOSIZE: 3361 case RTLD_DI_SERINFO: 3362 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3363 break; 3364 3365 default: 3366 _rtld_error("Invalid request %d passed to dlinfo()", request); 3367 error = -1; 3368 } 3369 3370 lock_release(rtld_bind_lock, &lockstate); 3371 3372 return (error); 3373 } 3374 3375 static void 3376 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3377 { 3378 3379 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3380 phdr_info->dlpi_name = obj->path; 3381 phdr_info->dlpi_phdr = obj->phdr; 3382 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3383 phdr_info->dlpi_tls_modid = obj->tlsindex; 3384 phdr_info->dlpi_tls_data = obj->tlsinit; 3385 phdr_info->dlpi_adds = obj_loads; 3386 phdr_info->dlpi_subs = obj_loads - obj_count; 3387 } 3388 3389 int 3390 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3391 { 3392 struct dl_phdr_info phdr_info; 3393 const Obj_Entry *obj; 3394 RtldLockState bind_lockstate, phdr_lockstate; 3395 int error; 3396 3397 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3398 rlock_acquire(rtld_bind_lock, &bind_lockstate); 3399 3400 error = 0; 3401 3402 for (obj = obj_list; obj != NULL; obj = obj->next) { 3403 rtld_fill_dl_phdr_info(obj, &phdr_info); 3404 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0) 3405 break; 3406 3407 } 3408 if (error == 0) { 3409 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3410 error = callback(&phdr_info, sizeof(phdr_info), param); 3411 } 3412 3413 lock_release(rtld_bind_lock, &bind_lockstate); 3414 lock_release(rtld_phdr_lock, &phdr_lockstate); 3415 3416 return (error); 3417 } 3418 3419 static void * 3420 fill_search_info(const char *dir, size_t dirlen, void *param) 3421 { 3422 struct fill_search_info_args *arg; 3423 3424 arg = param; 3425 3426 if (arg->request == RTLD_DI_SERINFOSIZE) { 3427 arg->serinfo->dls_cnt ++; 3428 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3429 } else { 3430 struct dl_serpath *s_entry; 3431 3432 s_entry = arg->serpath; 3433 s_entry->dls_name = arg->strspace; 3434 s_entry->dls_flags = arg->flags; 3435 3436 strncpy(arg->strspace, dir, dirlen); 3437 arg->strspace[dirlen] = '\0'; 3438 3439 arg->strspace += dirlen + 1; 3440 arg->serpath++; 3441 } 3442 3443 return (NULL); 3444 } 3445 3446 static int 3447 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3448 { 3449 struct dl_serinfo _info; 3450 struct fill_search_info_args args; 3451 3452 args.request = RTLD_DI_SERINFOSIZE; 3453 args.serinfo = &_info; 3454 3455 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3456 _info.dls_cnt = 0; 3457 3458 path_enumerate(obj->rpath, fill_search_info, &args); 3459 path_enumerate(ld_library_path, fill_search_info, &args); 3460 path_enumerate(obj->runpath, fill_search_info, &args); 3461 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args); 3462 if (!obj->z_nodeflib) 3463 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 3464 3465 3466 if (request == RTLD_DI_SERINFOSIZE) { 3467 info->dls_size = _info.dls_size; 3468 info->dls_cnt = _info.dls_cnt; 3469 return (0); 3470 } 3471 3472 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3473 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3474 return (-1); 3475 } 3476 3477 args.request = RTLD_DI_SERINFO; 3478 args.serinfo = info; 3479 args.serpath = &info->dls_serpath[0]; 3480 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3481 3482 args.flags = LA_SER_RUNPATH; 3483 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 3484 return (-1); 3485 3486 args.flags = LA_SER_LIBPATH; 3487 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 3488 return (-1); 3489 3490 args.flags = LA_SER_RUNPATH; 3491 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL) 3492 return (-1); 3493 3494 args.flags = LA_SER_CONFIG; 3495 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args) 3496 != NULL) 3497 return (-1); 3498 3499 args.flags = LA_SER_DEFAULT; 3500 if (!obj->z_nodeflib && 3501 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 3502 return (-1); 3503 return (0); 3504 } 3505 3506 static int 3507 rtld_dirname(const char *path, char *bname) 3508 { 3509 const char *endp; 3510 3511 /* Empty or NULL string gets treated as "." */ 3512 if (path == NULL || *path == '\0') { 3513 bname[0] = '.'; 3514 bname[1] = '\0'; 3515 return (0); 3516 } 3517 3518 /* Strip trailing slashes */ 3519 endp = path + strlen(path) - 1; 3520 while (endp > path && *endp == '/') 3521 endp--; 3522 3523 /* Find the start of the dir */ 3524 while (endp > path && *endp != '/') 3525 endp--; 3526 3527 /* Either the dir is "/" or there are no slashes */ 3528 if (endp == path) { 3529 bname[0] = *endp == '/' ? '/' : '.'; 3530 bname[1] = '\0'; 3531 return (0); 3532 } else { 3533 do { 3534 endp--; 3535 } while (endp > path && *endp == '/'); 3536 } 3537 3538 if (endp - path + 2 > PATH_MAX) 3539 { 3540 _rtld_error("Filename is too long: %s", path); 3541 return(-1); 3542 } 3543 3544 strncpy(bname, path, endp - path + 1); 3545 bname[endp - path + 1] = '\0'; 3546 return (0); 3547 } 3548 3549 static int 3550 rtld_dirname_abs(const char *path, char *base) 3551 { 3552 char base_rel[PATH_MAX]; 3553 3554 if (rtld_dirname(path, base) == -1) 3555 return (-1); 3556 if (base[0] == '/') 3557 return (0); 3558 if (getcwd(base_rel, sizeof(base_rel)) == NULL || 3559 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) || 3560 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel)) 3561 return (-1); 3562 strcpy(base, base_rel); 3563 return (0); 3564 } 3565 3566 static void 3567 linkmap_add(Obj_Entry *obj) 3568 { 3569 struct link_map *l = &obj->linkmap; 3570 struct link_map *prev; 3571 3572 obj->linkmap.l_name = obj->path; 3573 obj->linkmap.l_addr = obj->mapbase; 3574 obj->linkmap.l_ld = obj->dynamic; 3575 #ifdef __mips__ 3576 /* GDB needs load offset on MIPS to use the symbols */ 3577 obj->linkmap.l_offs = obj->relocbase; 3578 #endif 3579 3580 if (r_debug.r_map == NULL) { 3581 r_debug.r_map = l; 3582 return; 3583 } 3584 3585 /* 3586 * Scan to the end of the list, but not past the entry for the 3587 * dynamic linker, which we want to keep at the very end. 3588 */ 3589 for (prev = r_debug.r_map; 3590 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3591 prev = prev->l_next) 3592 ; 3593 3594 /* Link in the new entry. */ 3595 l->l_prev = prev; 3596 l->l_next = prev->l_next; 3597 if (l->l_next != NULL) 3598 l->l_next->l_prev = l; 3599 prev->l_next = l; 3600 } 3601 3602 static void 3603 linkmap_delete(Obj_Entry *obj) 3604 { 3605 struct link_map *l = &obj->linkmap; 3606 3607 if (l->l_prev == NULL) { 3608 if ((r_debug.r_map = l->l_next) != NULL) 3609 l->l_next->l_prev = NULL; 3610 return; 3611 } 3612 3613 if ((l->l_prev->l_next = l->l_next) != NULL) 3614 l->l_next->l_prev = l->l_prev; 3615 } 3616 3617 /* 3618 * Function for the debugger to set a breakpoint on to gain control. 3619 * 3620 * The two parameters allow the debugger to easily find and determine 3621 * what the runtime loader is doing and to whom it is doing it. 3622 * 3623 * When the loadhook trap is hit (r_debug_state, set at program 3624 * initialization), the arguments can be found on the stack: 3625 * 3626 * +8 struct link_map *m 3627 * +4 struct r_debug *rd 3628 * +0 RetAddr 3629 */ 3630 void 3631 r_debug_state(struct r_debug* rd, struct link_map *m) 3632 { 3633 /* 3634 * The following is a hack to force the compiler to emit calls to 3635 * this function, even when optimizing. If the function is empty, 3636 * the compiler is not obliged to emit any code for calls to it, 3637 * even when marked __noinline. However, gdb depends on those 3638 * calls being made. 3639 */ 3640 __compiler_membar(); 3641 } 3642 3643 /* 3644 * A function called after init routines have completed. This can be used to 3645 * break before a program's entry routine is called, and can be used when 3646 * main is not available in the symbol table. 3647 */ 3648 void 3649 _r_debug_postinit(struct link_map *m) 3650 { 3651 3652 /* See r_debug_state(). */ 3653 __compiler_membar(); 3654 } 3655 3656 /* 3657 * Get address of the pointer variable in the main program. 3658 * Prefer non-weak symbol over the weak one. 3659 */ 3660 static const void ** 3661 get_program_var_addr(const char *name, RtldLockState *lockstate) 3662 { 3663 SymLook req; 3664 DoneList donelist; 3665 3666 symlook_init(&req, name); 3667 req.lockstate = lockstate; 3668 donelist_init(&donelist); 3669 if (symlook_global(&req, &donelist) != 0) 3670 return (NULL); 3671 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 3672 return ((const void **)make_function_pointer(req.sym_out, 3673 req.defobj_out)); 3674 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 3675 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 3676 else 3677 return ((const void **)(req.defobj_out->relocbase + 3678 req.sym_out->st_value)); 3679 } 3680 3681 /* 3682 * Set a pointer variable in the main program to the given value. This 3683 * is used to set key variables such as "environ" before any of the 3684 * init functions are called. 3685 */ 3686 static void 3687 set_program_var(const char *name, const void *value) 3688 { 3689 const void **addr; 3690 3691 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 3692 dbg("\"%s\": *%p <-- %p", name, addr, value); 3693 *addr = value; 3694 } 3695 } 3696 3697 /* 3698 * Search the global objects, including dependencies and main object, 3699 * for the given symbol. 3700 */ 3701 static int 3702 symlook_global(SymLook *req, DoneList *donelist) 3703 { 3704 SymLook req1; 3705 const Objlist_Entry *elm; 3706 int res; 3707 3708 symlook_init_from_req(&req1, req); 3709 3710 /* Search all objects loaded at program start up. */ 3711 if (req->defobj_out == NULL || 3712 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3713 res = symlook_list(&req1, &list_main, donelist); 3714 if (res == 0 && (req->defobj_out == NULL || 3715 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3716 req->sym_out = req1.sym_out; 3717 req->defobj_out = req1.defobj_out; 3718 assert(req->defobj_out != NULL); 3719 } 3720 } 3721 3722 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 3723 STAILQ_FOREACH(elm, &list_global, link) { 3724 if (req->defobj_out != NULL && 3725 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3726 break; 3727 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 3728 if (res == 0 && (req->defobj_out == NULL || 3729 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3730 req->sym_out = req1.sym_out; 3731 req->defobj_out = req1.defobj_out; 3732 assert(req->defobj_out != NULL); 3733 } 3734 } 3735 3736 return (req->sym_out != NULL ? 0 : ESRCH); 3737 } 3738 3739 /* 3740 * Given a symbol name in a referencing object, find the corresponding 3741 * definition of the symbol. Returns a pointer to the symbol, or NULL if 3742 * no definition was found. Returns a pointer to the Obj_Entry of the 3743 * defining object via the reference parameter DEFOBJ_OUT. 3744 */ 3745 static int 3746 symlook_default(SymLook *req, const Obj_Entry *refobj) 3747 { 3748 DoneList donelist; 3749 const Objlist_Entry *elm; 3750 SymLook req1; 3751 int res; 3752 3753 donelist_init(&donelist); 3754 symlook_init_from_req(&req1, req); 3755 3756 /* Look first in the referencing object if linked symbolically. */ 3757 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 3758 res = symlook_obj(&req1, refobj); 3759 if (res == 0) { 3760 req->sym_out = req1.sym_out; 3761 req->defobj_out = req1.defobj_out; 3762 assert(req->defobj_out != NULL); 3763 } 3764 } 3765 3766 symlook_global(req, &donelist); 3767 3768 /* Search all dlopened DAGs containing the referencing object. */ 3769 STAILQ_FOREACH(elm, &refobj->dldags, link) { 3770 if (req->sym_out != NULL && 3771 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3772 break; 3773 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 3774 if (res == 0 && (req->sym_out == NULL || 3775 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3776 req->sym_out = req1.sym_out; 3777 req->defobj_out = req1.defobj_out; 3778 assert(req->defobj_out != NULL); 3779 } 3780 } 3781 3782 /* 3783 * Search the dynamic linker itself, and possibly resolve the 3784 * symbol from there. This is how the application links to 3785 * dynamic linker services such as dlopen. 3786 */ 3787 if (req->sym_out == NULL || 3788 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3789 res = symlook_obj(&req1, &obj_rtld); 3790 if (res == 0) { 3791 req->sym_out = req1.sym_out; 3792 req->defobj_out = req1.defobj_out; 3793 assert(req->defobj_out != NULL); 3794 } 3795 } 3796 3797 return (req->sym_out != NULL ? 0 : ESRCH); 3798 } 3799 3800 static int 3801 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 3802 { 3803 const Elf_Sym *def; 3804 const Obj_Entry *defobj; 3805 const Objlist_Entry *elm; 3806 SymLook req1; 3807 int res; 3808 3809 def = NULL; 3810 defobj = NULL; 3811 STAILQ_FOREACH(elm, objlist, link) { 3812 if (donelist_check(dlp, elm->obj)) 3813 continue; 3814 symlook_init_from_req(&req1, req); 3815 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 3816 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3817 def = req1.sym_out; 3818 defobj = req1.defobj_out; 3819 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3820 break; 3821 } 3822 } 3823 } 3824 if (def != NULL) { 3825 req->sym_out = def; 3826 req->defobj_out = defobj; 3827 return (0); 3828 } 3829 return (ESRCH); 3830 } 3831 3832 /* 3833 * Search the chain of DAGS cointed to by the given Needed_Entry 3834 * for a symbol of the given name. Each DAG is scanned completely 3835 * before advancing to the next one. Returns a pointer to the symbol, 3836 * or NULL if no definition was found. 3837 */ 3838 static int 3839 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 3840 { 3841 const Elf_Sym *def; 3842 const Needed_Entry *n; 3843 const Obj_Entry *defobj; 3844 SymLook req1; 3845 int res; 3846 3847 def = NULL; 3848 defobj = NULL; 3849 symlook_init_from_req(&req1, req); 3850 for (n = needed; n != NULL; n = n->next) { 3851 if (n->obj == NULL || 3852 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 3853 continue; 3854 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3855 def = req1.sym_out; 3856 defobj = req1.defobj_out; 3857 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3858 break; 3859 } 3860 } 3861 if (def != NULL) { 3862 req->sym_out = def; 3863 req->defobj_out = defobj; 3864 return (0); 3865 } 3866 return (ESRCH); 3867 } 3868 3869 /* 3870 * Search the symbol table of a single shared object for a symbol of 3871 * the given name and version, if requested. Returns a pointer to the 3872 * symbol, or NULL if no definition was found. If the object is 3873 * filter, return filtered symbol from filtee. 3874 * 3875 * The symbol's hash value is passed in for efficiency reasons; that 3876 * eliminates many recomputations of the hash value. 3877 */ 3878 int 3879 symlook_obj(SymLook *req, const Obj_Entry *obj) 3880 { 3881 DoneList donelist; 3882 SymLook req1; 3883 int flags, res, mres; 3884 3885 /* 3886 * If there is at least one valid hash at this point, we prefer to 3887 * use the faster GNU version if available. 3888 */ 3889 if (obj->valid_hash_gnu) 3890 mres = symlook_obj1_gnu(req, obj); 3891 else if (obj->valid_hash_sysv) 3892 mres = symlook_obj1_sysv(req, obj); 3893 else 3894 return (EINVAL); 3895 3896 if (mres == 0) { 3897 if (obj->needed_filtees != NULL) { 3898 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3899 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3900 donelist_init(&donelist); 3901 symlook_init_from_req(&req1, req); 3902 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 3903 if (res == 0) { 3904 req->sym_out = req1.sym_out; 3905 req->defobj_out = req1.defobj_out; 3906 } 3907 return (res); 3908 } 3909 if (obj->needed_aux_filtees != NULL) { 3910 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3911 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3912 donelist_init(&donelist); 3913 symlook_init_from_req(&req1, req); 3914 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 3915 if (res == 0) { 3916 req->sym_out = req1.sym_out; 3917 req->defobj_out = req1.defobj_out; 3918 return (res); 3919 } 3920 } 3921 } 3922 return (mres); 3923 } 3924 3925 /* Symbol match routine common to both hash functions */ 3926 static bool 3927 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 3928 const unsigned long symnum) 3929 { 3930 Elf_Versym verndx; 3931 const Elf_Sym *symp; 3932 const char *strp; 3933 3934 symp = obj->symtab + symnum; 3935 strp = obj->strtab + symp->st_name; 3936 3937 switch (ELF_ST_TYPE(symp->st_info)) { 3938 case STT_FUNC: 3939 case STT_NOTYPE: 3940 case STT_OBJECT: 3941 case STT_COMMON: 3942 case STT_GNU_IFUNC: 3943 if (symp->st_value == 0) 3944 return (false); 3945 /* fallthrough */ 3946 case STT_TLS: 3947 if (symp->st_shndx != SHN_UNDEF) 3948 break; 3949 #ifndef __mips__ 3950 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 3951 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 3952 break; 3953 /* fallthrough */ 3954 #endif 3955 default: 3956 return (false); 3957 } 3958 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 3959 return (false); 3960 3961 if (req->ventry == NULL) { 3962 if (obj->versyms != NULL) { 3963 verndx = VER_NDX(obj->versyms[symnum]); 3964 if (verndx > obj->vernum) { 3965 _rtld_error( 3966 "%s: symbol %s references wrong version %d", 3967 obj->path, obj->strtab + symnum, verndx); 3968 return (false); 3969 } 3970 /* 3971 * If we are not called from dlsym (i.e. this 3972 * is a normal relocation from unversioned 3973 * binary), accept the symbol immediately if 3974 * it happens to have first version after this 3975 * shared object became versioned. Otherwise, 3976 * if symbol is versioned and not hidden, 3977 * remember it. If it is the only symbol with 3978 * this name exported by the shared object, it 3979 * will be returned as a match by the calling 3980 * function. If symbol is global (verndx < 2) 3981 * accept it unconditionally. 3982 */ 3983 if ((req->flags & SYMLOOK_DLSYM) == 0 && 3984 verndx == VER_NDX_GIVEN) { 3985 result->sym_out = symp; 3986 return (true); 3987 } 3988 else if (verndx >= VER_NDX_GIVEN) { 3989 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 3990 == 0) { 3991 if (result->vsymp == NULL) 3992 result->vsymp = symp; 3993 result->vcount++; 3994 } 3995 return (false); 3996 } 3997 } 3998 result->sym_out = symp; 3999 return (true); 4000 } 4001 if (obj->versyms == NULL) { 4002 if (object_match_name(obj, req->ventry->name)) { 4003 _rtld_error("%s: object %s should provide version %s " 4004 "for symbol %s", obj_rtld.path, obj->path, 4005 req->ventry->name, obj->strtab + symnum); 4006 return (false); 4007 } 4008 } else { 4009 verndx = VER_NDX(obj->versyms[symnum]); 4010 if (verndx > obj->vernum) { 4011 _rtld_error("%s: symbol %s references wrong version %d", 4012 obj->path, obj->strtab + symnum, verndx); 4013 return (false); 4014 } 4015 if (obj->vertab[verndx].hash != req->ventry->hash || 4016 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4017 /* 4018 * Version does not match. Look if this is a 4019 * global symbol and if it is not hidden. If 4020 * global symbol (verndx < 2) is available, 4021 * use it. Do not return symbol if we are 4022 * called by dlvsym, because dlvsym looks for 4023 * a specific version and default one is not 4024 * what dlvsym wants. 4025 */ 4026 if ((req->flags & SYMLOOK_DLSYM) || 4027 (verndx >= VER_NDX_GIVEN) || 4028 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4029 return (false); 4030 } 4031 } 4032 result->sym_out = symp; 4033 return (true); 4034 } 4035 4036 /* 4037 * Search for symbol using SysV hash function. 4038 * obj->buckets is known not to be NULL at this point; the test for this was 4039 * performed with the obj->valid_hash_sysv assignment. 4040 */ 4041 static int 4042 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4043 { 4044 unsigned long symnum; 4045 Sym_Match_Result matchres; 4046 4047 matchres.sym_out = NULL; 4048 matchres.vsymp = NULL; 4049 matchres.vcount = 0; 4050 4051 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4052 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4053 if (symnum >= obj->nchains) 4054 return (ESRCH); /* Bad object */ 4055 4056 if (matched_symbol(req, obj, &matchres, symnum)) { 4057 req->sym_out = matchres.sym_out; 4058 req->defobj_out = obj; 4059 return (0); 4060 } 4061 } 4062 if (matchres.vcount == 1) { 4063 req->sym_out = matchres.vsymp; 4064 req->defobj_out = obj; 4065 return (0); 4066 } 4067 return (ESRCH); 4068 } 4069 4070 /* Search for symbol using GNU hash function */ 4071 static int 4072 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4073 { 4074 Elf_Addr bloom_word; 4075 const Elf32_Word *hashval; 4076 Elf32_Word bucket; 4077 Sym_Match_Result matchres; 4078 unsigned int h1, h2; 4079 unsigned long symnum; 4080 4081 matchres.sym_out = NULL; 4082 matchres.vsymp = NULL; 4083 matchres.vcount = 0; 4084 4085 /* Pick right bitmask word from Bloom filter array */ 4086 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4087 obj->maskwords_bm_gnu]; 4088 4089 /* Calculate modulus word size of gnu hash and its derivative */ 4090 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4091 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4092 4093 /* Filter out the "definitely not in set" queries */ 4094 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4095 return (ESRCH); 4096 4097 /* Locate hash chain and corresponding value element*/ 4098 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4099 if (bucket == 0) 4100 return (ESRCH); 4101 hashval = &obj->chain_zero_gnu[bucket]; 4102 do { 4103 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4104 symnum = hashval - obj->chain_zero_gnu; 4105 if (matched_symbol(req, obj, &matchres, symnum)) { 4106 req->sym_out = matchres.sym_out; 4107 req->defobj_out = obj; 4108 return (0); 4109 } 4110 } 4111 } while ((*hashval++ & 1) == 0); 4112 if (matchres.vcount == 1) { 4113 req->sym_out = matchres.vsymp; 4114 req->defobj_out = obj; 4115 return (0); 4116 } 4117 return (ESRCH); 4118 } 4119 4120 static void 4121 trace_loaded_objects(Obj_Entry *obj) 4122 { 4123 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4124 int c; 4125 4126 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 4127 main_local = ""; 4128 4129 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL) 4130 fmt1 = "\t%o => %p (%x)\n"; 4131 4132 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL) 4133 fmt2 = "\t%o (%x)\n"; 4134 4135 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL"); 4136 4137 for (; obj; obj = obj->next) { 4138 Needed_Entry *needed; 4139 char *name, *path; 4140 bool is_lib; 4141 4142 if (list_containers && obj->needed != NULL) 4143 rtld_printf("%s:\n", obj->path); 4144 for (needed = obj->needed; needed; needed = needed->next) { 4145 if (needed->obj != NULL) { 4146 if (needed->obj->traced && !list_containers) 4147 continue; 4148 needed->obj->traced = true; 4149 path = needed->obj->path; 4150 } else 4151 path = "not found"; 4152 4153 name = (char *)obj->strtab + needed->name; 4154 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4155 4156 fmt = is_lib ? fmt1 : fmt2; 4157 while ((c = *fmt++) != '\0') { 4158 switch (c) { 4159 default: 4160 rtld_putchar(c); 4161 continue; 4162 case '\\': 4163 switch (c = *fmt) { 4164 case '\0': 4165 continue; 4166 case 'n': 4167 rtld_putchar('\n'); 4168 break; 4169 case 't': 4170 rtld_putchar('\t'); 4171 break; 4172 } 4173 break; 4174 case '%': 4175 switch (c = *fmt) { 4176 case '\0': 4177 continue; 4178 case '%': 4179 default: 4180 rtld_putchar(c); 4181 break; 4182 case 'A': 4183 rtld_putstr(main_local); 4184 break; 4185 case 'a': 4186 rtld_putstr(obj_main->path); 4187 break; 4188 case 'o': 4189 rtld_putstr(name); 4190 break; 4191 #if 0 4192 case 'm': 4193 rtld_printf("%d", sodp->sod_major); 4194 break; 4195 case 'n': 4196 rtld_printf("%d", sodp->sod_minor); 4197 break; 4198 #endif 4199 case 'p': 4200 rtld_putstr(path); 4201 break; 4202 case 'x': 4203 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4204 0); 4205 break; 4206 } 4207 break; 4208 } 4209 ++fmt; 4210 } 4211 } 4212 } 4213 } 4214 4215 /* 4216 * Unload a dlopened object and its dependencies from memory and from 4217 * our data structures. It is assumed that the DAG rooted in the 4218 * object has already been unreferenced, and that the object has a 4219 * reference count of 0. 4220 */ 4221 static void 4222 unload_object(Obj_Entry *root) 4223 { 4224 Obj_Entry *obj; 4225 Obj_Entry **linkp; 4226 4227 assert(root->refcount == 0); 4228 4229 /* 4230 * Pass over the DAG removing unreferenced objects from 4231 * appropriate lists. 4232 */ 4233 unlink_object(root); 4234 4235 /* Unmap all objects that are no longer referenced. */ 4236 linkp = &obj_list->next; 4237 while ((obj = *linkp) != NULL) { 4238 if (obj->refcount == 0) { 4239 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 4240 obj->path); 4241 dbg("unloading \"%s\"", obj->path); 4242 unload_filtees(root); 4243 munmap(obj->mapbase, obj->mapsize); 4244 linkmap_delete(obj); 4245 *linkp = obj->next; 4246 obj_count--; 4247 obj_free(obj); 4248 } else 4249 linkp = &obj->next; 4250 } 4251 obj_tail = linkp; 4252 } 4253 4254 static void 4255 unlink_object(Obj_Entry *root) 4256 { 4257 Objlist_Entry *elm; 4258 4259 if (root->refcount == 0) { 4260 /* Remove the object from the RTLD_GLOBAL list. */ 4261 objlist_remove(&list_global, root); 4262 4263 /* Remove the object from all objects' DAG lists. */ 4264 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4265 objlist_remove(&elm->obj->dldags, root); 4266 if (elm->obj != root) 4267 unlink_object(elm->obj); 4268 } 4269 } 4270 } 4271 4272 static void 4273 ref_dag(Obj_Entry *root) 4274 { 4275 Objlist_Entry *elm; 4276 4277 assert(root->dag_inited); 4278 STAILQ_FOREACH(elm, &root->dagmembers, link) 4279 elm->obj->refcount++; 4280 } 4281 4282 static void 4283 unref_dag(Obj_Entry *root) 4284 { 4285 Objlist_Entry *elm; 4286 4287 assert(root->dag_inited); 4288 STAILQ_FOREACH(elm, &root->dagmembers, link) 4289 elm->obj->refcount--; 4290 } 4291 4292 /* 4293 * Common code for MD __tls_get_addr(). 4294 */ 4295 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4296 static void * 4297 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4298 { 4299 Elf_Addr *newdtv, *dtv; 4300 RtldLockState lockstate; 4301 int to_copy; 4302 4303 dtv = *dtvp; 4304 /* Check dtv generation in case new modules have arrived */ 4305 if (dtv[0] != tls_dtv_generation) { 4306 wlock_acquire(rtld_bind_lock, &lockstate); 4307 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4308 to_copy = dtv[1]; 4309 if (to_copy > tls_max_index) 4310 to_copy = tls_max_index; 4311 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4312 newdtv[0] = tls_dtv_generation; 4313 newdtv[1] = tls_max_index; 4314 free(dtv); 4315 lock_release(rtld_bind_lock, &lockstate); 4316 dtv = *dtvp = newdtv; 4317 } 4318 4319 /* Dynamically allocate module TLS if necessary */ 4320 if (dtv[index + 1] == 0) { 4321 /* Signal safe, wlock will block out signals. */ 4322 wlock_acquire(rtld_bind_lock, &lockstate); 4323 if (!dtv[index + 1]) 4324 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4325 lock_release(rtld_bind_lock, &lockstate); 4326 } 4327 return ((void *)(dtv[index + 1] + offset)); 4328 } 4329 4330 void * 4331 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4332 { 4333 Elf_Addr *dtv; 4334 4335 dtv = *dtvp; 4336 /* Check dtv generation in case new modules have arrived */ 4337 if (__predict_true(dtv[0] == tls_dtv_generation && 4338 dtv[index + 1] != 0)) 4339 return ((void *)(dtv[index + 1] + offset)); 4340 return (tls_get_addr_slow(dtvp, index, offset)); 4341 } 4342 4343 #if defined(__arm__) || defined(__mips__) || defined(__powerpc__) 4344 4345 /* 4346 * Allocate Static TLS using the Variant I method. 4347 */ 4348 void * 4349 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4350 { 4351 Obj_Entry *obj; 4352 char *tcb; 4353 Elf_Addr **tls; 4354 Elf_Addr *dtv; 4355 Elf_Addr addr; 4356 int i; 4357 4358 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4359 return (oldtcb); 4360 4361 assert(tcbsize >= TLS_TCB_SIZE); 4362 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 4363 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 4364 4365 if (oldtcb != NULL) { 4366 memcpy(tls, oldtcb, tls_static_space); 4367 free(oldtcb); 4368 4369 /* Adjust the DTV. */ 4370 dtv = tls[0]; 4371 for (i = 0; i < dtv[1]; i++) { 4372 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4373 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4374 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 4375 } 4376 } 4377 } else { 4378 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4379 tls[0] = dtv; 4380 dtv[0] = tls_dtv_generation; 4381 dtv[1] = tls_max_index; 4382 4383 for (obj = objs; obj; obj = obj->next) { 4384 if (obj->tlsoffset > 0) { 4385 addr = (Elf_Addr)tls + obj->tlsoffset; 4386 if (obj->tlsinitsize > 0) 4387 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4388 if (obj->tlssize > obj->tlsinitsize) 4389 memset((void*) (addr + obj->tlsinitsize), 0, 4390 obj->tlssize - obj->tlsinitsize); 4391 dtv[obj->tlsindex + 1] = addr; 4392 } 4393 } 4394 } 4395 4396 return (tcb); 4397 } 4398 4399 void 4400 free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4401 { 4402 Elf_Addr *dtv; 4403 Elf_Addr tlsstart, tlsend; 4404 int dtvsize, i; 4405 4406 assert(tcbsize >= TLS_TCB_SIZE); 4407 4408 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 4409 tlsend = tlsstart + tls_static_space; 4410 4411 dtv = *(Elf_Addr **)tlsstart; 4412 dtvsize = dtv[1]; 4413 for (i = 0; i < dtvsize; i++) { 4414 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4415 free((void*)dtv[i+2]); 4416 } 4417 } 4418 free(dtv); 4419 free(tcb); 4420 } 4421 4422 #endif 4423 4424 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 4425 4426 /* 4427 * Allocate Static TLS using the Variant II method. 4428 */ 4429 void * 4430 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4431 { 4432 Obj_Entry *obj; 4433 size_t size, ralign; 4434 char *tls; 4435 Elf_Addr *dtv, *olddtv; 4436 Elf_Addr segbase, oldsegbase, addr; 4437 int i; 4438 4439 ralign = tcbalign; 4440 if (tls_static_max_align > ralign) 4441 ralign = tls_static_max_align; 4442 size = round(tls_static_space, ralign) + round(tcbsize, ralign); 4443 4444 assert(tcbsize >= 2*sizeof(Elf_Addr)); 4445 tls = malloc_aligned(size, ralign); 4446 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4447 4448 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign)); 4449 ((Elf_Addr*)segbase)[0] = segbase; 4450 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 4451 4452 dtv[0] = tls_dtv_generation; 4453 dtv[1] = tls_max_index; 4454 4455 if (oldtls) { 4456 /* 4457 * Copy the static TLS block over whole. 4458 */ 4459 oldsegbase = (Elf_Addr) oldtls; 4460 memcpy((void *)(segbase - tls_static_space), 4461 (const void *)(oldsegbase - tls_static_space), 4462 tls_static_space); 4463 4464 /* 4465 * If any dynamic TLS blocks have been created tls_get_addr(), 4466 * move them over. 4467 */ 4468 olddtv = ((Elf_Addr**)oldsegbase)[1]; 4469 for (i = 0; i < olddtv[1]; i++) { 4470 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 4471 dtv[i+2] = olddtv[i+2]; 4472 olddtv[i+2] = 0; 4473 } 4474 } 4475 4476 /* 4477 * We assume that this block was the one we created with 4478 * allocate_initial_tls(). 4479 */ 4480 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 4481 } else { 4482 for (obj = objs; obj; obj = obj->next) { 4483 if (obj->tlsoffset) { 4484 addr = segbase - obj->tlsoffset; 4485 memset((void*) (addr + obj->tlsinitsize), 4486 0, obj->tlssize - obj->tlsinitsize); 4487 if (obj->tlsinit) 4488 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4489 dtv[obj->tlsindex + 1] = addr; 4490 } 4491 } 4492 } 4493 4494 return (void*) segbase; 4495 } 4496 4497 void 4498 free_tls(void *tls, size_t tcbsize, size_t tcbalign) 4499 { 4500 Elf_Addr* dtv; 4501 size_t size, ralign; 4502 int dtvsize, i; 4503 Elf_Addr tlsstart, tlsend; 4504 4505 /* 4506 * Figure out the size of the initial TLS block so that we can 4507 * find stuff which ___tls_get_addr() allocated dynamically. 4508 */ 4509 ralign = tcbalign; 4510 if (tls_static_max_align > ralign) 4511 ralign = tls_static_max_align; 4512 size = round(tls_static_space, ralign); 4513 4514 dtv = ((Elf_Addr**)tls)[1]; 4515 dtvsize = dtv[1]; 4516 tlsend = (Elf_Addr) tls; 4517 tlsstart = tlsend - size; 4518 for (i = 0; i < dtvsize; i++) { 4519 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 4520 free_aligned((void *)dtv[i + 2]); 4521 } 4522 } 4523 4524 free_aligned((void *)tlsstart); 4525 free((void*) dtv); 4526 } 4527 4528 #endif 4529 4530 /* 4531 * Allocate TLS block for module with given index. 4532 */ 4533 void * 4534 allocate_module_tls(int index) 4535 { 4536 Obj_Entry* obj; 4537 char* p; 4538 4539 for (obj = obj_list; obj; obj = obj->next) { 4540 if (obj->tlsindex == index) 4541 break; 4542 } 4543 if (!obj) { 4544 _rtld_error("Can't find module with TLS index %d", index); 4545 die(); 4546 } 4547 4548 p = malloc_aligned(obj->tlssize, obj->tlsalign); 4549 memcpy(p, obj->tlsinit, obj->tlsinitsize); 4550 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 4551 4552 return p; 4553 } 4554 4555 bool 4556 allocate_tls_offset(Obj_Entry *obj) 4557 { 4558 size_t off; 4559 4560 if (obj->tls_done) 4561 return true; 4562 4563 if (obj->tlssize == 0) { 4564 obj->tls_done = true; 4565 return true; 4566 } 4567 4568 if (obj->tlsindex == 1) 4569 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 4570 else 4571 off = calculate_tls_offset(tls_last_offset, tls_last_size, 4572 obj->tlssize, obj->tlsalign); 4573 4574 /* 4575 * If we have already fixed the size of the static TLS block, we 4576 * must stay within that size. When allocating the static TLS, we 4577 * leave a small amount of space spare to be used for dynamically 4578 * loading modules which use static TLS. 4579 */ 4580 if (tls_static_space != 0) { 4581 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 4582 return false; 4583 } else if (obj->tlsalign > tls_static_max_align) { 4584 tls_static_max_align = obj->tlsalign; 4585 } 4586 4587 tls_last_offset = obj->tlsoffset = off; 4588 tls_last_size = obj->tlssize; 4589 obj->tls_done = true; 4590 4591 return true; 4592 } 4593 4594 void 4595 free_tls_offset(Obj_Entry *obj) 4596 { 4597 4598 /* 4599 * If we were the last thing to allocate out of the static TLS 4600 * block, we give our space back to the 'allocator'. This is a 4601 * simplistic workaround to allow libGL.so.1 to be loaded and 4602 * unloaded multiple times. 4603 */ 4604 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 4605 == calculate_tls_end(tls_last_offset, tls_last_size)) { 4606 tls_last_offset -= obj->tlssize; 4607 tls_last_size = 0; 4608 } 4609 } 4610 4611 void * 4612 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 4613 { 4614 void *ret; 4615 RtldLockState lockstate; 4616 4617 wlock_acquire(rtld_bind_lock, &lockstate); 4618 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign); 4619 lock_release(rtld_bind_lock, &lockstate); 4620 return (ret); 4621 } 4622 4623 void 4624 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4625 { 4626 RtldLockState lockstate; 4627 4628 wlock_acquire(rtld_bind_lock, &lockstate); 4629 free_tls(tcb, tcbsize, tcbalign); 4630 lock_release(rtld_bind_lock, &lockstate); 4631 } 4632 4633 static void 4634 object_add_name(Obj_Entry *obj, const char *name) 4635 { 4636 Name_Entry *entry; 4637 size_t len; 4638 4639 len = strlen(name); 4640 entry = malloc(sizeof(Name_Entry) + len); 4641 4642 if (entry != NULL) { 4643 strcpy(entry->name, name); 4644 STAILQ_INSERT_TAIL(&obj->names, entry, link); 4645 } 4646 } 4647 4648 static int 4649 object_match_name(const Obj_Entry *obj, const char *name) 4650 { 4651 Name_Entry *entry; 4652 4653 STAILQ_FOREACH(entry, &obj->names, link) { 4654 if (strcmp(name, entry->name) == 0) 4655 return (1); 4656 } 4657 return (0); 4658 } 4659 4660 static Obj_Entry * 4661 locate_dependency(const Obj_Entry *obj, const char *name) 4662 { 4663 const Objlist_Entry *entry; 4664 const Needed_Entry *needed; 4665 4666 STAILQ_FOREACH(entry, &list_main, link) { 4667 if (object_match_name(entry->obj, name)) 4668 return entry->obj; 4669 } 4670 4671 for (needed = obj->needed; needed != NULL; needed = needed->next) { 4672 if (strcmp(obj->strtab + needed->name, name) == 0 || 4673 (needed->obj != NULL && object_match_name(needed->obj, name))) { 4674 /* 4675 * If there is DT_NEEDED for the name we are looking for, 4676 * we are all set. Note that object might not be found if 4677 * dependency was not loaded yet, so the function can 4678 * return NULL here. This is expected and handled 4679 * properly by the caller. 4680 */ 4681 return (needed->obj); 4682 } 4683 } 4684 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 4685 obj->path, name); 4686 die(); 4687 } 4688 4689 static int 4690 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 4691 const Elf_Vernaux *vna) 4692 { 4693 const Elf_Verdef *vd; 4694 const char *vername; 4695 4696 vername = refobj->strtab + vna->vna_name; 4697 vd = depobj->verdef; 4698 if (vd == NULL) { 4699 _rtld_error("%s: version %s required by %s not defined", 4700 depobj->path, vername, refobj->path); 4701 return (-1); 4702 } 4703 for (;;) { 4704 if (vd->vd_version != VER_DEF_CURRENT) { 4705 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4706 depobj->path, vd->vd_version); 4707 return (-1); 4708 } 4709 if (vna->vna_hash == vd->vd_hash) { 4710 const Elf_Verdaux *aux = (const Elf_Verdaux *) 4711 ((char *)vd + vd->vd_aux); 4712 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 4713 return (0); 4714 } 4715 if (vd->vd_next == 0) 4716 break; 4717 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4718 } 4719 if (vna->vna_flags & VER_FLG_WEAK) 4720 return (0); 4721 _rtld_error("%s: version %s required by %s not found", 4722 depobj->path, vername, refobj->path); 4723 return (-1); 4724 } 4725 4726 static int 4727 rtld_verify_object_versions(Obj_Entry *obj) 4728 { 4729 const Elf_Verneed *vn; 4730 const Elf_Verdef *vd; 4731 const Elf_Verdaux *vda; 4732 const Elf_Vernaux *vna; 4733 const Obj_Entry *depobj; 4734 int maxvernum, vernum; 4735 4736 if (obj->ver_checked) 4737 return (0); 4738 obj->ver_checked = true; 4739 4740 maxvernum = 0; 4741 /* 4742 * Walk over defined and required version records and figure out 4743 * max index used by any of them. Do very basic sanity checking 4744 * while there. 4745 */ 4746 vn = obj->verneed; 4747 while (vn != NULL) { 4748 if (vn->vn_version != VER_NEED_CURRENT) { 4749 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 4750 obj->path, vn->vn_version); 4751 return (-1); 4752 } 4753 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4754 for (;;) { 4755 vernum = VER_NEED_IDX(vna->vna_other); 4756 if (vernum > maxvernum) 4757 maxvernum = vernum; 4758 if (vna->vna_next == 0) 4759 break; 4760 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4761 } 4762 if (vn->vn_next == 0) 4763 break; 4764 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4765 } 4766 4767 vd = obj->verdef; 4768 while (vd != NULL) { 4769 if (vd->vd_version != VER_DEF_CURRENT) { 4770 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4771 obj->path, vd->vd_version); 4772 return (-1); 4773 } 4774 vernum = VER_DEF_IDX(vd->vd_ndx); 4775 if (vernum > maxvernum) 4776 maxvernum = vernum; 4777 if (vd->vd_next == 0) 4778 break; 4779 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4780 } 4781 4782 if (maxvernum == 0) 4783 return (0); 4784 4785 /* 4786 * Store version information in array indexable by version index. 4787 * Verify that object version requirements are satisfied along the 4788 * way. 4789 */ 4790 obj->vernum = maxvernum + 1; 4791 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 4792 4793 vd = obj->verdef; 4794 while (vd != NULL) { 4795 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 4796 vernum = VER_DEF_IDX(vd->vd_ndx); 4797 assert(vernum <= maxvernum); 4798 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 4799 obj->vertab[vernum].hash = vd->vd_hash; 4800 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 4801 obj->vertab[vernum].file = NULL; 4802 obj->vertab[vernum].flags = 0; 4803 } 4804 if (vd->vd_next == 0) 4805 break; 4806 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4807 } 4808 4809 vn = obj->verneed; 4810 while (vn != NULL) { 4811 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 4812 if (depobj == NULL) 4813 return (-1); 4814 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4815 for (;;) { 4816 if (check_object_provided_version(obj, depobj, vna)) 4817 return (-1); 4818 vernum = VER_NEED_IDX(vna->vna_other); 4819 assert(vernum <= maxvernum); 4820 obj->vertab[vernum].hash = vna->vna_hash; 4821 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 4822 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 4823 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 4824 VER_INFO_HIDDEN : 0; 4825 if (vna->vna_next == 0) 4826 break; 4827 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4828 } 4829 if (vn->vn_next == 0) 4830 break; 4831 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4832 } 4833 return 0; 4834 } 4835 4836 static int 4837 rtld_verify_versions(const Objlist *objlist) 4838 { 4839 Objlist_Entry *entry; 4840 int rc; 4841 4842 rc = 0; 4843 STAILQ_FOREACH(entry, objlist, link) { 4844 /* 4845 * Skip dummy objects or objects that have their version requirements 4846 * already checked. 4847 */ 4848 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 4849 continue; 4850 if (rtld_verify_object_versions(entry->obj) == -1) { 4851 rc = -1; 4852 if (ld_tracing == NULL) 4853 break; 4854 } 4855 } 4856 if (rc == 0 || ld_tracing != NULL) 4857 rc = rtld_verify_object_versions(&obj_rtld); 4858 return rc; 4859 } 4860 4861 const Ver_Entry * 4862 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 4863 { 4864 Elf_Versym vernum; 4865 4866 if (obj->vertab) { 4867 vernum = VER_NDX(obj->versyms[symnum]); 4868 if (vernum >= obj->vernum) { 4869 _rtld_error("%s: symbol %s has wrong verneed value %d", 4870 obj->path, obj->strtab + symnum, vernum); 4871 } else if (obj->vertab[vernum].hash != 0) { 4872 return &obj->vertab[vernum]; 4873 } 4874 } 4875 return NULL; 4876 } 4877 4878 int 4879 _rtld_get_stack_prot(void) 4880 { 4881 4882 return (stack_prot); 4883 } 4884 4885 static void 4886 map_stacks_exec(RtldLockState *lockstate) 4887 { 4888 void (*thr_map_stacks_exec)(void); 4889 4890 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 4891 return; 4892 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 4893 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 4894 if (thr_map_stacks_exec != NULL) { 4895 stack_prot |= PROT_EXEC; 4896 thr_map_stacks_exec(); 4897 } 4898 } 4899 4900 void 4901 symlook_init(SymLook *dst, const char *name) 4902 { 4903 4904 bzero(dst, sizeof(*dst)); 4905 dst->name = name; 4906 dst->hash = elf_hash(name); 4907 dst->hash_gnu = gnu_hash(name); 4908 } 4909 4910 static void 4911 symlook_init_from_req(SymLook *dst, const SymLook *src) 4912 { 4913 4914 dst->name = src->name; 4915 dst->hash = src->hash; 4916 dst->hash_gnu = src->hash_gnu; 4917 dst->ventry = src->ventry; 4918 dst->flags = src->flags; 4919 dst->defobj_out = NULL; 4920 dst->sym_out = NULL; 4921 dst->lockstate = src->lockstate; 4922 } 4923 4924 4925 /* 4926 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 4927 */ 4928 static int 4929 parse_libdir(const char *str) 4930 { 4931 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 4932 const char *orig; 4933 int fd; 4934 char c; 4935 4936 orig = str; 4937 fd = 0; 4938 for (c = *str; c != '\0'; c = *++str) { 4939 if (c < '0' || c > '9') 4940 return (-1); 4941 4942 fd *= RADIX; 4943 fd += c - '0'; 4944 } 4945 4946 /* Make sure we actually parsed something. */ 4947 if (str == orig) { 4948 _rtld_error("failed to parse directory FD from '%s'", str); 4949 return (-1); 4950 } 4951 return (fd); 4952 } 4953 4954 /* 4955 * Overrides for libc_pic-provided functions. 4956 */ 4957 4958 int 4959 __getosreldate(void) 4960 { 4961 size_t len; 4962 int oid[2]; 4963 int error, osrel; 4964 4965 if (osreldate != 0) 4966 return (osreldate); 4967 4968 oid[0] = CTL_KERN; 4969 oid[1] = KERN_OSRELDATE; 4970 osrel = 0; 4971 len = sizeof(osrel); 4972 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 4973 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 4974 osreldate = osrel; 4975 return (osreldate); 4976 } 4977 4978 void 4979 exit(int status) 4980 { 4981 4982 _exit(status); 4983 } 4984 4985 void (*__cleanup)(void); 4986 int __isthreaded = 0; 4987 int _thread_autoinit_dummy_decl = 1; 4988 4989 /* 4990 * No unresolved symbols for rtld. 4991 */ 4992 void 4993 __pthread_cxa_finalize(struct dl_phdr_info *a) 4994 { 4995 } 4996 4997 void 4998 __stack_chk_fail(void) 4999 { 5000 5001 _rtld_error("stack overflow detected; terminated"); 5002 die(); 5003 } 5004 __weak_reference(__stack_chk_fail, __stack_chk_fail_local); 5005 5006 void 5007 __chk_fail(void) 5008 { 5009 5010 _rtld_error("buffer overflow detected; terminated"); 5011 die(); 5012 } 5013 5014 const char * 5015 rtld_strerror(int errnum) 5016 { 5017 5018 if (errnum < 0 || errnum >= sys_nerr) 5019 return ("Unknown error"); 5020 return (sys_errlist[errnum]); 5021 } 5022