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 #ifndef COMPAT_32BIT 507 /* 508 * Get the actual dynamic linker pathname from the executable if 509 * possible. (It should always be possible.) That ensures that 510 * gdb will find the right dynamic linker even if a non-standard 511 * one is being used. 512 */ 513 if (obj_main->interp != NULL && 514 strcmp(obj_main->interp, obj_rtld.path) != 0) { 515 free(obj_rtld.path); 516 obj_rtld.path = xstrdup(obj_main->interp); 517 __progname = obj_rtld.path; 518 } 519 #endif 520 521 digest_dynamic(obj_main, 0); 522 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 523 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 524 obj_main->dynsymcount); 525 526 linkmap_add(obj_main); 527 linkmap_add(&obj_rtld); 528 529 /* Link the main program into the list of objects. */ 530 *obj_tail = obj_main; 531 obj_tail = &obj_main->next; 532 obj_count++; 533 obj_loads++; 534 535 /* Initialize a fake symbol for resolving undefined weak references. */ 536 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 537 sym_zero.st_shndx = SHN_UNDEF; 538 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 539 540 if (!libmap_disable) 541 libmap_disable = (bool)lm_init(libmap_override); 542 543 dbg("loading LD_PRELOAD libraries"); 544 if (load_preload_objects() == -1) 545 die(); 546 preload_tail = obj_tail; 547 548 dbg("loading needed objects"); 549 if (load_needed_objects(obj_main, 0) == -1) 550 die(); 551 552 /* Make a list of all objects loaded at startup. */ 553 last_interposer = obj_main; 554 for (obj = obj_list; obj != NULL; obj = obj->next) { 555 if (obj->z_interpose && obj != obj_main) { 556 objlist_put_after(&list_main, last_interposer, obj); 557 last_interposer = obj; 558 } else { 559 objlist_push_tail(&list_main, obj); 560 } 561 obj->refcount++; 562 } 563 564 dbg("checking for required versions"); 565 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 566 die(); 567 568 if (ld_tracing) { /* We're done */ 569 trace_loaded_objects(obj_main); 570 exit(0); 571 } 572 573 if (getenv(LD_ "DUMP_REL_PRE") != NULL) { 574 dump_relocations(obj_main); 575 exit (0); 576 } 577 578 /* 579 * Processing tls relocations requires having the tls offsets 580 * initialized. Prepare offsets before starting initial 581 * relocation processing. 582 */ 583 dbg("initializing initial thread local storage offsets"); 584 STAILQ_FOREACH(entry, &list_main, link) { 585 /* 586 * Allocate all the initial objects out of the static TLS 587 * block even if they didn't ask for it. 588 */ 589 allocate_tls_offset(entry->obj); 590 } 591 592 if (relocate_objects(obj_main, 593 ld_bind_now != NULL && *ld_bind_now != '\0', 594 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 595 die(); 596 597 dbg("doing copy relocations"); 598 if (do_copy_relocations(obj_main) == -1) 599 die(); 600 601 if (getenv(LD_ "DUMP_REL_POST") != NULL) { 602 dump_relocations(obj_main); 603 exit (0); 604 } 605 606 /* 607 * Setup TLS for main thread. This must be done after the 608 * relocations are processed, since tls initialization section 609 * might be the subject for relocations. 610 */ 611 dbg("initializing initial thread local storage"); 612 allocate_initial_tls(obj_list); 613 614 dbg("initializing key program variables"); 615 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 616 set_program_var("environ", env); 617 set_program_var("__elf_aux_vector", aux); 618 619 /* Make a list of init functions to call. */ 620 objlist_init(&initlist); 621 initlist_add_objects(obj_list, preload_tail, &initlist); 622 623 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 624 625 map_stacks_exec(NULL); 626 627 dbg("resolving ifuncs"); 628 if (resolve_objects_ifunc(obj_main, 629 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY, 630 NULL) == -1) 631 die(); 632 633 if (!obj_main->crt_no_init) { 634 /* 635 * Make sure we don't call the main program's init and fini 636 * functions for binaries linked with old crt1 which calls 637 * _init itself. 638 */ 639 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 640 obj_main->preinit_array = obj_main->init_array = 641 obj_main->fini_array = (Elf_Addr)NULL; 642 } 643 644 wlock_acquire(rtld_bind_lock, &lockstate); 645 if (obj_main->crt_no_init) 646 preinit_main(); 647 objlist_call_init(&initlist, &lockstate); 648 _r_debug_postinit(&obj_main->linkmap); 649 objlist_clear(&initlist); 650 dbg("loading filtees"); 651 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 652 if (ld_loadfltr || obj->z_loadfltr) 653 load_filtees(obj, 0, &lockstate); 654 } 655 lock_release(rtld_bind_lock, &lockstate); 656 657 dbg("transferring control to program entry point = %p", obj_main->entry); 658 659 /* Return the exit procedure and the program entry point. */ 660 *exit_proc = rtld_exit; 661 *objp = obj_main; 662 return (func_ptr_type) obj_main->entry; 663 } 664 665 void * 666 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 667 { 668 void *ptr; 669 Elf_Addr target; 670 671 ptr = (void *)make_function_pointer(def, obj); 672 target = ((Elf_Addr (*)(void))ptr)(); 673 return ((void *)target); 674 } 675 676 Elf_Addr 677 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 678 { 679 const Elf_Rel *rel; 680 const Elf_Sym *def; 681 const Obj_Entry *defobj; 682 Elf_Addr *where; 683 Elf_Addr target; 684 RtldLockState lockstate; 685 686 rlock_acquire(rtld_bind_lock, &lockstate); 687 if (sigsetjmp(lockstate.env, 0) != 0) 688 lock_upgrade(rtld_bind_lock, &lockstate); 689 if (obj->pltrel) 690 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 691 else 692 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 693 694 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 695 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL, 696 &lockstate); 697 if (def == NULL) 698 die(); 699 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 700 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 701 else 702 target = (Elf_Addr)(defobj->relocbase + def->st_value); 703 704 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 705 defobj->strtab + def->st_name, basename(obj->path), 706 (void *)target, basename(defobj->path)); 707 708 /* 709 * Write the new contents for the jmpslot. Note that depending on 710 * architecture, the value which we need to return back to the 711 * lazy binding trampoline may or may not be the target 712 * address. The value returned from reloc_jmpslot() is the value 713 * that the trampoline needs. 714 */ 715 target = reloc_jmpslot(where, target, defobj, obj, rel); 716 lock_release(rtld_bind_lock, &lockstate); 717 return target; 718 } 719 720 /* 721 * Error reporting function. Use it like printf. If formats the message 722 * into a buffer, and sets things up so that the next call to dlerror() 723 * will return the message. 724 */ 725 void 726 _rtld_error(const char *fmt, ...) 727 { 728 static char buf[512]; 729 va_list ap; 730 731 va_start(ap, fmt); 732 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 733 error_message = buf; 734 va_end(ap); 735 } 736 737 /* 738 * Return a dynamically-allocated copy of the current error message, if any. 739 */ 740 static char * 741 errmsg_save(void) 742 { 743 return error_message == NULL ? NULL : xstrdup(error_message); 744 } 745 746 /* 747 * Restore the current error message from a copy which was previously saved 748 * by errmsg_save(). The copy is freed. 749 */ 750 static void 751 errmsg_restore(char *saved_msg) 752 { 753 if (saved_msg == NULL) 754 error_message = NULL; 755 else { 756 _rtld_error("%s", saved_msg); 757 free(saved_msg); 758 } 759 } 760 761 static const char * 762 basename(const char *name) 763 { 764 const char *p = strrchr(name, '/'); 765 return p != NULL ? p + 1 : name; 766 } 767 768 static struct utsname uts; 769 770 static char * 771 origin_subst_one(char *real, const char *kw, const char *subst, 772 bool may_free) 773 { 774 char *p, *p1, *res, *resp; 775 int subst_len, kw_len, subst_count, old_len, new_len; 776 777 kw_len = strlen(kw); 778 779 /* 780 * First, count the number of the keyword occurences, to 781 * preallocate the final string. 782 */ 783 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 784 p1 = strstr(p, kw); 785 if (p1 == NULL) 786 break; 787 } 788 789 /* 790 * If the keyword is not found, just return. 791 */ 792 if (subst_count == 0) 793 return (may_free ? real : xstrdup(real)); 794 795 /* 796 * There is indeed something to substitute. Calculate the 797 * length of the resulting string, and allocate it. 798 */ 799 subst_len = strlen(subst); 800 old_len = strlen(real); 801 new_len = old_len + (subst_len - kw_len) * subst_count; 802 res = xmalloc(new_len + 1); 803 804 /* 805 * Now, execute the substitution loop. 806 */ 807 for (p = real, resp = res, *resp = '\0';;) { 808 p1 = strstr(p, kw); 809 if (p1 != NULL) { 810 /* Copy the prefix before keyword. */ 811 memcpy(resp, p, p1 - p); 812 resp += p1 - p; 813 /* Keyword replacement. */ 814 memcpy(resp, subst, subst_len); 815 resp += subst_len; 816 *resp = '\0'; 817 p = p1 + kw_len; 818 } else 819 break; 820 } 821 822 /* Copy to the end of string and finish. */ 823 strcat(resp, p); 824 if (may_free) 825 free(real); 826 return (res); 827 } 828 829 static char * 830 origin_subst(char *real, const char *origin_path) 831 { 832 char *res1, *res2, *res3, *res4; 833 834 if (uts.sysname[0] == '\0') { 835 if (uname(&uts) != 0) { 836 _rtld_error("utsname failed: %d", errno); 837 return (NULL); 838 } 839 } 840 res1 = origin_subst_one(real, "$ORIGIN", origin_path, false); 841 res2 = origin_subst_one(res1, "$OSNAME", uts.sysname, true); 842 res3 = origin_subst_one(res2, "$OSREL", uts.release, true); 843 res4 = origin_subst_one(res3, "$PLATFORM", uts.machine, true); 844 return (res4); 845 } 846 847 static void 848 die(void) 849 { 850 const char *msg = dlerror(); 851 852 if (msg == NULL) 853 msg = "Fatal error"; 854 rtld_fdputstr(STDERR_FILENO, msg); 855 rtld_fdputchar(STDERR_FILENO, '\n'); 856 _exit(1); 857 } 858 859 /* 860 * Process a shared object's DYNAMIC section, and save the important 861 * information in its Obj_Entry structure. 862 */ 863 static void 864 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 865 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 866 { 867 const Elf_Dyn *dynp; 868 Needed_Entry **needed_tail = &obj->needed; 869 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 870 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 871 const Elf_Hashelt *hashtab; 872 const Elf32_Word *hashval; 873 Elf32_Word bkt, nmaskwords; 874 int bloom_size32; 875 bool nmw_power2; 876 int plttype = DT_REL; 877 878 *dyn_rpath = NULL; 879 *dyn_soname = NULL; 880 *dyn_runpath = NULL; 881 882 obj->bind_now = false; 883 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 884 switch (dynp->d_tag) { 885 886 case DT_REL: 887 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 888 break; 889 890 case DT_RELSZ: 891 obj->relsize = dynp->d_un.d_val; 892 break; 893 894 case DT_RELENT: 895 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 896 break; 897 898 case DT_JMPREL: 899 obj->pltrel = (const Elf_Rel *) 900 (obj->relocbase + dynp->d_un.d_ptr); 901 break; 902 903 case DT_PLTRELSZ: 904 obj->pltrelsize = dynp->d_un.d_val; 905 break; 906 907 case DT_RELA: 908 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 909 break; 910 911 case DT_RELASZ: 912 obj->relasize = dynp->d_un.d_val; 913 break; 914 915 case DT_RELAENT: 916 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 917 break; 918 919 case DT_PLTREL: 920 plttype = dynp->d_un.d_val; 921 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 922 break; 923 924 case DT_SYMTAB: 925 obj->symtab = (const Elf_Sym *) 926 (obj->relocbase + dynp->d_un.d_ptr); 927 break; 928 929 case DT_SYMENT: 930 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 931 break; 932 933 case DT_STRTAB: 934 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 935 break; 936 937 case DT_STRSZ: 938 obj->strsize = dynp->d_un.d_val; 939 break; 940 941 case DT_VERNEED: 942 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 943 dynp->d_un.d_val); 944 break; 945 946 case DT_VERNEEDNUM: 947 obj->verneednum = dynp->d_un.d_val; 948 break; 949 950 case DT_VERDEF: 951 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 952 dynp->d_un.d_val); 953 break; 954 955 case DT_VERDEFNUM: 956 obj->verdefnum = dynp->d_un.d_val; 957 break; 958 959 case DT_VERSYM: 960 obj->versyms = (const Elf_Versym *)(obj->relocbase + 961 dynp->d_un.d_val); 962 break; 963 964 case DT_HASH: 965 { 966 hashtab = (const Elf_Hashelt *)(obj->relocbase + 967 dynp->d_un.d_ptr); 968 obj->nbuckets = hashtab[0]; 969 obj->nchains = hashtab[1]; 970 obj->buckets = hashtab + 2; 971 obj->chains = obj->buckets + obj->nbuckets; 972 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 973 obj->buckets != NULL; 974 } 975 break; 976 977 case DT_GNU_HASH: 978 { 979 hashtab = (const Elf_Hashelt *)(obj->relocbase + 980 dynp->d_un.d_ptr); 981 obj->nbuckets_gnu = hashtab[0]; 982 obj->symndx_gnu = hashtab[1]; 983 nmaskwords = hashtab[2]; 984 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 985 /* Number of bitmask words is required to be power of 2 */ 986 nmw_power2 = ((nmaskwords & (nmaskwords - 1)) == 0); 987 obj->maskwords_bm_gnu = nmaskwords - 1; 988 obj->shift2_gnu = hashtab[3]; 989 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4); 990 obj->buckets_gnu = hashtab + 4 + bloom_size32; 991 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 992 obj->symndx_gnu; 993 obj->valid_hash_gnu = nmw_power2 && obj->nbuckets_gnu > 0 && 994 obj->buckets_gnu != NULL; 995 } 996 break; 997 998 case DT_NEEDED: 999 if (!obj->rtld) { 1000 Needed_Entry *nep = NEW(Needed_Entry); 1001 nep->name = dynp->d_un.d_val; 1002 nep->obj = NULL; 1003 nep->next = NULL; 1004 1005 *needed_tail = nep; 1006 needed_tail = &nep->next; 1007 } 1008 break; 1009 1010 case DT_FILTER: 1011 if (!obj->rtld) { 1012 Needed_Entry *nep = NEW(Needed_Entry); 1013 nep->name = dynp->d_un.d_val; 1014 nep->obj = NULL; 1015 nep->next = NULL; 1016 1017 *needed_filtees_tail = nep; 1018 needed_filtees_tail = &nep->next; 1019 } 1020 break; 1021 1022 case DT_AUXILIARY: 1023 if (!obj->rtld) { 1024 Needed_Entry *nep = NEW(Needed_Entry); 1025 nep->name = dynp->d_un.d_val; 1026 nep->obj = NULL; 1027 nep->next = NULL; 1028 1029 *needed_aux_filtees_tail = nep; 1030 needed_aux_filtees_tail = &nep->next; 1031 } 1032 break; 1033 1034 case DT_PLTGOT: 1035 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 1036 break; 1037 1038 case DT_TEXTREL: 1039 obj->textrel = true; 1040 break; 1041 1042 case DT_SYMBOLIC: 1043 obj->symbolic = true; 1044 break; 1045 1046 case DT_RPATH: 1047 /* 1048 * We have to wait until later to process this, because we 1049 * might not have gotten the address of the string table yet. 1050 */ 1051 *dyn_rpath = dynp; 1052 break; 1053 1054 case DT_SONAME: 1055 *dyn_soname = dynp; 1056 break; 1057 1058 case DT_RUNPATH: 1059 *dyn_runpath = dynp; 1060 break; 1061 1062 case DT_INIT: 1063 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1064 break; 1065 1066 case DT_PREINIT_ARRAY: 1067 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1068 break; 1069 1070 case DT_PREINIT_ARRAYSZ: 1071 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1072 break; 1073 1074 case DT_INIT_ARRAY: 1075 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1076 break; 1077 1078 case DT_INIT_ARRAYSZ: 1079 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1080 break; 1081 1082 case DT_FINI: 1083 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1084 break; 1085 1086 case DT_FINI_ARRAY: 1087 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1088 break; 1089 1090 case DT_FINI_ARRAYSZ: 1091 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1092 break; 1093 1094 /* 1095 * Don't process DT_DEBUG on MIPS as the dynamic section 1096 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1097 */ 1098 1099 #ifndef __mips__ 1100 case DT_DEBUG: 1101 /* XXX - not implemented yet */ 1102 if (!early) 1103 dbg("Filling in DT_DEBUG entry"); 1104 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 1105 break; 1106 #endif 1107 1108 case DT_FLAGS: 1109 if ((dynp->d_un.d_val & DF_ORIGIN) && trust) 1110 obj->z_origin = true; 1111 if (dynp->d_un.d_val & DF_SYMBOLIC) 1112 obj->symbolic = true; 1113 if (dynp->d_un.d_val & DF_TEXTREL) 1114 obj->textrel = true; 1115 if (dynp->d_un.d_val & DF_BIND_NOW) 1116 obj->bind_now = true; 1117 /*if (dynp->d_un.d_val & DF_STATIC_TLS) 1118 ;*/ 1119 break; 1120 #ifdef __mips__ 1121 case DT_MIPS_LOCAL_GOTNO: 1122 obj->local_gotno = dynp->d_un.d_val; 1123 break; 1124 1125 case DT_MIPS_SYMTABNO: 1126 obj->symtabno = dynp->d_un.d_val; 1127 break; 1128 1129 case DT_MIPS_GOTSYM: 1130 obj->gotsym = dynp->d_un.d_val; 1131 break; 1132 1133 case DT_MIPS_RLD_MAP: 1134 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1135 break; 1136 #endif 1137 1138 case DT_FLAGS_1: 1139 if (dynp->d_un.d_val & DF_1_NOOPEN) 1140 obj->z_noopen = true; 1141 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust) 1142 obj->z_origin = true; 1143 /*if (dynp->d_un.d_val & DF_1_GLOBAL) 1144 XXX ;*/ 1145 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1146 obj->bind_now = true; 1147 if (dynp->d_un.d_val & DF_1_NODELETE) 1148 obj->z_nodelete = true; 1149 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1150 obj->z_loadfltr = true; 1151 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1152 obj->z_interpose = true; 1153 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1154 obj->z_nodeflib = true; 1155 break; 1156 1157 default: 1158 if (!early) { 1159 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1160 (long)dynp->d_tag); 1161 } 1162 break; 1163 } 1164 } 1165 1166 obj->traced = false; 1167 1168 if (plttype == DT_RELA) { 1169 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1170 obj->pltrel = NULL; 1171 obj->pltrelasize = obj->pltrelsize; 1172 obj->pltrelsize = 0; 1173 } 1174 1175 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1176 if (obj->valid_hash_sysv) 1177 obj->dynsymcount = obj->nchains; 1178 else if (obj->valid_hash_gnu) { 1179 obj->dynsymcount = 0; 1180 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1181 if (obj->buckets_gnu[bkt] == 0) 1182 continue; 1183 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1184 do 1185 obj->dynsymcount++; 1186 while ((*hashval++ & 1u) == 0); 1187 } 1188 obj->dynsymcount += obj->symndx_gnu; 1189 } 1190 } 1191 1192 static void 1193 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1194 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1195 { 1196 1197 if (obj->z_origin && obj->origin_path == NULL) { 1198 obj->origin_path = xmalloc(PATH_MAX); 1199 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1) 1200 die(); 1201 } 1202 1203 if (dyn_runpath != NULL) { 1204 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val; 1205 if (obj->z_origin) 1206 obj->runpath = origin_subst(obj->runpath, obj->origin_path); 1207 } 1208 else if (dyn_rpath != NULL) { 1209 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 1210 if (obj->z_origin) 1211 obj->rpath = origin_subst(obj->rpath, obj->origin_path); 1212 } 1213 1214 if (dyn_soname != NULL) 1215 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1216 } 1217 1218 static void 1219 digest_dynamic(Obj_Entry *obj, int early) 1220 { 1221 const Elf_Dyn *dyn_rpath; 1222 const Elf_Dyn *dyn_soname; 1223 const Elf_Dyn *dyn_runpath; 1224 1225 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1226 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath); 1227 } 1228 1229 /* 1230 * Process a shared object's program header. This is used only for the 1231 * main program, when the kernel has already loaded the main program 1232 * into memory before calling the dynamic linker. It creates and 1233 * returns an Obj_Entry structure. 1234 */ 1235 static Obj_Entry * 1236 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1237 { 1238 Obj_Entry *obj; 1239 const Elf_Phdr *phlimit = phdr + phnum; 1240 const Elf_Phdr *ph; 1241 Elf_Addr note_start, note_end; 1242 int nsegs = 0; 1243 1244 obj = obj_new(); 1245 for (ph = phdr; ph < phlimit; ph++) { 1246 if (ph->p_type != PT_PHDR) 1247 continue; 1248 1249 obj->phdr = phdr; 1250 obj->phsize = ph->p_memsz; 1251 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1252 break; 1253 } 1254 1255 obj->stack_flags = PF_X | PF_R | PF_W; 1256 1257 for (ph = phdr; ph < phlimit; ph++) { 1258 switch (ph->p_type) { 1259 1260 case PT_INTERP: 1261 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1262 break; 1263 1264 case PT_LOAD: 1265 if (nsegs == 0) { /* First load segment */ 1266 obj->vaddrbase = trunc_page(ph->p_vaddr); 1267 obj->mapbase = obj->vaddrbase + obj->relocbase; 1268 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1269 obj->vaddrbase; 1270 } else { /* Last load segment */ 1271 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1272 obj->vaddrbase; 1273 } 1274 nsegs++; 1275 break; 1276 1277 case PT_DYNAMIC: 1278 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1279 break; 1280 1281 case PT_TLS: 1282 obj->tlsindex = 1; 1283 obj->tlssize = ph->p_memsz; 1284 obj->tlsalign = ph->p_align; 1285 obj->tlsinitsize = ph->p_filesz; 1286 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1287 break; 1288 1289 case PT_GNU_STACK: 1290 obj->stack_flags = ph->p_flags; 1291 break; 1292 1293 case PT_GNU_RELRO: 1294 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1295 obj->relro_size = round_page(ph->p_memsz); 1296 break; 1297 1298 case PT_NOTE: 1299 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1300 note_end = note_start + ph->p_filesz; 1301 digest_notes(obj, note_start, note_end); 1302 break; 1303 } 1304 } 1305 if (nsegs < 1) { 1306 _rtld_error("%s: too few PT_LOAD segments", path); 1307 return NULL; 1308 } 1309 1310 obj->entry = entry; 1311 return obj; 1312 } 1313 1314 void 1315 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1316 { 1317 const Elf_Note *note; 1318 const char *note_name; 1319 uintptr_t p; 1320 1321 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1322 note = (const Elf_Note *)((const char *)(note + 1) + 1323 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1324 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1325 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1326 note->n_descsz != sizeof(int32_t)) 1327 continue; 1328 if (note->n_type != ABI_NOTETYPE && 1329 note->n_type != CRT_NOINIT_NOTETYPE) 1330 continue; 1331 note_name = (const char *)(note + 1); 1332 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1333 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1334 continue; 1335 switch (note->n_type) { 1336 case ABI_NOTETYPE: 1337 /* FreeBSD osrel note */ 1338 p = (uintptr_t)(note + 1); 1339 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1340 obj->osrel = *(const int32_t *)(p); 1341 dbg("note osrel %d", obj->osrel); 1342 break; 1343 case CRT_NOINIT_NOTETYPE: 1344 /* FreeBSD 'crt does not call init' note */ 1345 obj->crt_no_init = true; 1346 dbg("note crt_no_init"); 1347 break; 1348 } 1349 } 1350 } 1351 1352 static Obj_Entry * 1353 dlcheck(void *handle) 1354 { 1355 Obj_Entry *obj; 1356 1357 for (obj = obj_list; obj != NULL; obj = obj->next) 1358 if (obj == (Obj_Entry *) handle) 1359 break; 1360 1361 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1362 _rtld_error("Invalid shared object handle %p", handle); 1363 return NULL; 1364 } 1365 return obj; 1366 } 1367 1368 /* 1369 * If the given object is already in the donelist, return true. Otherwise 1370 * add the object to the list and return false. 1371 */ 1372 static bool 1373 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1374 { 1375 unsigned int i; 1376 1377 for (i = 0; i < dlp->num_used; i++) 1378 if (dlp->objs[i] == obj) 1379 return true; 1380 /* 1381 * Our donelist allocation should always be sufficient. But if 1382 * our threads locking isn't working properly, more shared objects 1383 * could have been loaded since we allocated the list. That should 1384 * never happen, but we'll handle it properly just in case it does. 1385 */ 1386 if (dlp->num_used < dlp->num_alloc) 1387 dlp->objs[dlp->num_used++] = obj; 1388 return false; 1389 } 1390 1391 /* 1392 * Hash function for symbol table lookup. Don't even think about changing 1393 * this. It is specified by the System V ABI. 1394 */ 1395 unsigned long 1396 elf_hash(const char *name) 1397 { 1398 const unsigned char *p = (const unsigned char *) name; 1399 unsigned long h = 0; 1400 unsigned long g; 1401 1402 while (*p != '\0') { 1403 h = (h << 4) + *p++; 1404 if ((g = h & 0xf0000000) != 0) 1405 h ^= g >> 24; 1406 h &= ~g; 1407 } 1408 return h; 1409 } 1410 1411 /* 1412 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1413 * unsigned in case it's implemented with a wider type. 1414 */ 1415 static uint32_t 1416 gnu_hash(const char *s) 1417 { 1418 uint32_t h; 1419 unsigned char c; 1420 1421 h = 5381; 1422 for (c = *s; c != '\0'; c = *++s) 1423 h = h * 33 + c; 1424 return (h & 0xffffffff); 1425 } 1426 1427 1428 /* 1429 * Find the library with the given name, and return its full pathname. 1430 * The returned string is dynamically allocated. Generates an error 1431 * message and returns NULL if the library cannot be found. 1432 * 1433 * If the second argument is non-NULL, then it refers to an already- 1434 * loaded shared object, whose library search path will be searched. 1435 * 1436 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1437 * descriptor (which is close-on-exec) will be passed out via the third 1438 * argument. 1439 * 1440 * The search order is: 1441 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1442 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1443 * LD_LIBRARY_PATH 1444 * DT_RUNPATH in the referencing file 1445 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1446 * from list) 1447 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1448 * 1449 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1450 */ 1451 static char * 1452 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1453 { 1454 char *pathname; 1455 char *name; 1456 bool nodeflib, objgiven; 1457 1458 objgiven = refobj != NULL; 1459 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */ 1460 if (xname[0] != '/' && !trust) { 1461 _rtld_error("Absolute pathname required for shared object \"%s\"", 1462 xname); 1463 return NULL; 1464 } 1465 if (objgiven && refobj->z_origin) { 1466 return (origin_subst(__DECONST(char *, xname), 1467 refobj->origin_path)); 1468 } else { 1469 return (xstrdup(xname)); 1470 } 1471 } 1472 1473 if (libmap_disable || !objgiven || 1474 (name = lm_find(refobj->path, xname)) == NULL) 1475 name = (char *)xname; 1476 1477 dbg(" Searching for \"%s\"", name); 1478 1479 /* 1480 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1481 * back to pre-conforming behaviour if user requested so with 1482 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1483 * nodeflib. 1484 */ 1485 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1486 if ((pathname = search_library_path(name, ld_library_path)) != NULL || 1487 (refobj != NULL && 1488 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1489 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL || 1490 (pathname = search_library_path(name, gethints(false))) != NULL || 1491 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL) 1492 return (pathname); 1493 } else { 1494 nodeflib = objgiven ? refobj->z_nodeflib : false; 1495 if ((objgiven && 1496 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1497 (objgiven && refobj->runpath == NULL && refobj != obj_main && 1498 (pathname = search_library_path(name, obj_main->rpath)) != NULL) || 1499 (pathname = search_library_path(name, ld_library_path)) != NULL || 1500 (objgiven && 1501 (pathname = search_library_path(name, refobj->runpath)) != NULL) || 1502 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL || 1503 (pathname = search_library_path(name, gethints(nodeflib))) != NULL || 1504 (objgiven && !nodeflib && 1505 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)) 1506 return (pathname); 1507 } 1508 1509 if (objgiven && refobj->path != NULL) { 1510 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 1511 name, basename(refobj->path)); 1512 } else { 1513 _rtld_error("Shared object \"%s\" not found", name); 1514 } 1515 return NULL; 1516 } 1517 1518 /* 1519 * Given a symbol number in a referencing object, find the corresponding 1520 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1521 * no definition was found. Returns a pointer to the Obj_Entry of the 1522 * defining object via the reference parameter DEFOBJ_OUT. 1523 */ 1524 const Elf_Sym * 1525 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1526 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1527 RtldLockState *lockstate) 1528 { 1529 const Elf_Sym *ref; 1530 const Elf_Sym *def; 1531 const Obj_Entry *defobj; 1532 SymLook req; 1533 const char *name; 1534 int res; 1535 1536 /* 1537 * If we have already found this symbol, get the information from 1538 * the cache. 1539 */ 1540 if (symnum >= refobj->dynsymcount) 1541 return NULL; /* Bad object */ 1542 if (cache != NULL && cache[symnum].sym != NULL) { 1543 *defobj_out = cache[symnum].obj; 1544 return cache[symnum].sym; 1545 } 1546 1547 ref = refobj->symtab + symnum; 1548 name = refobj->strtab + ref->st_name; 1549 def = NULL; 1550 defobj = NULL; 1551 1552 /* 1553 * We don't have to do a full scale lookup if the symbol is local. 1554 * We know it will bind to the instance in this load module; to 1555 * which we already have a pointer (ie ref). By not doing a lookup, 1556 * we not only improve performance, but it also avoids unresolvable 1557 * symbols when local symbols are not in the hash table. This has 1558 * been seen with the ia64 toolchain. 1559 */ 1560 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1561 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1562 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1563 symnum); 1564 } 1565 symlook_init(&req, name); 1566 req.flags = flags; 1567 req.ventry = fetch_ventry(refobj, symnum); 1568 req.lockstate = lockstate; 1569 res = symlook_default(&req, refobj); 1570 if (res == 0) { 1571 def = req.sym_out; 1572 defobj = req.defobj_out; 1573 } 1574 } else { 1575 def = ref; 1576 defobj = refobj; 1577 } 1578 1579 /* 1580 * If we found no definition and the reference is weak, treat the 1581 * symbol as having the value zero. 1582 */ 1583 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1584 def = &sym_zero; 1585 defobj = obj_main; 1586 } 1587 1588 if (def != NULL) { 1589 *defobj_out = defobj; 1590 /* Record the information in the cache to avoid subsequent lookups. */ 1591 if (cache != NULL) { 1592 cache[symnum].sym = def; 1593 cache[symnum].obj = defobj; 1594 } 1595 } else { 1596 if (refobj != &obj_rtld) 1597 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name); 1598 } 1599 return def; 1600 } 1601 1602 /* 1603 * Return the search path from the ldconfig hints file, reading it if 1604 * necessary. If nostdlib is true, then the default search paths are 1605 * not added to result. 1606 * 1607 * Returns NULL if there are problems with the hints file, 1608 * or if the search path there is empty. 1609 */ 1610 static const char * 1611 gethints(bool nostdlib) 1612 { 1613 static char *hints, *filtered_path; 1614 struct elfhints_hdr hdr; 1615 struct fill_search_info_args sargs, hargs; 1616 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1617 struct dl_serpath *SLPpath, *hintpath; 1618 char *p; 1619 unsigned int SLPndx, hintndx, fndx, fcount; 1620 int fd; 1621 size_t flen; 1622 bool skip; 1623 1624 /* First call, read the hints file */ 1625 if (hints == NULL) { 1626 /* Keep from trying again in case the hints file is bad. */ 1627 hints = ""; 1628 1629 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1630 return (NULL); 1631 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1632 hdr.magic != ELFHINTS_MAGIC || 1633 hdr.version != 1) { 1634 close(fd); 1635 return (NULL); 1636 } 1637 p = xmalloc(hdr.dirlistlen + 1); 1638 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1639 read(fd, p, hdr.dirlistlen + 1) != 1640 (ssize_t)hdr.dirlistlen + 1) { 1641 free(p); 1642 close(fd); 1643 return (NULL); 1644 } 1645 hints = p; 1646 close(fd); 1647 } 1648 1649 /* 1650 * If caller agreed to receive list which includes the default 1651 * paths, we are done. Otherwise, if we still did not 1652 * calculated filtered result, do it now. 1653 */ 1654 if (!nostdlib) 1655 return (hints[0] != '\0' ? hints : NULL); 1656 if (filtered_path != NULL) 1657 goto filt_ret; 1658 1659 /* 1660 * Obtain the list of all configured search paths, and the 1661 * list of the default paths. 1662 * 1663 * First estimate the size of the results. 1664 */ 1665 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1666 smeta.dls_cnt = 0; 1667 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1668 hmeta.dls_cnt = 0; 1669 1670 sargs.request = RTLD_DI_SERINFOSIZE; 1671 sargs.serinfo = &smeta; 1672 hargs.request = RTLD_DI_SERINFOSIZE; 1673 hargs.serinfo = &hmeta; 1674 1675 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1676 path_enumerate(p, fill_search_info, &hargs); 1677 1678 SLPinfo = xmalloc(smeta.dls_size); 1679 hintinfo = xmalloc(hmeta.dls_size); 1680 1681 /* 1682 * Next fetch both sets of paths. 1683 */ 1684 sargs.request = RTLD_DI_SERINFO; 1685 sargs.serinfo = SLPinfo; 1686 sargs.serpath = &SLPinfo->dls_serpath[0]; 1687 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1688 1689 hargs.request = RTLD_DI_SERINFO; 1690 hargs.serinfo = hintinfo; 1691 hargs.serpath = &hintinfo->dls_serpath[0]; 1692 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1693 1694 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1695 path_enumerate(p, fill_search_info, &hargs); 1696 1697 /* 1698 * Now calculate the difference between two sets, by excluding 1699 * standard paths from the full set. 1700 */ 1701 fndx = 0; 1702 fcount = 0; 1703 filtered_path = xmalloc(hdr.dirlistlen + 1); 1704 hintpath = &hintinfo->dls_serpath[0]; 1705 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1706 skip = false; 1707 SLPpath = &SLPinfo->dls_serpath[0]; 1708 /* 1709 * Check each standard path against current. 1710 */ 1711 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1712 /* matched, skip the path */ 1713 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1714 skip = true; 1715 break; 1716 } 1717 } 1718 if (skip) 1719 continue; 1720 /* 1721 * Not matched against any standard path, add the path 1722 * to result. Separate consequtive paths with ':'. 1723 */ 1724 if (fcount > 0) { 1725 filtered_path[fndx] = ':'; 1726 fndx++; 1727 } 1728 fcount++; 1729 flen = strlen(hintpath->dls_name); 1730 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1731 fndx += flen; 1732 } 1733 filtered_path[fndx] = '\0'; 1734 1735 free(SLPinfo); 1736 free(hintinfo); 1737 1738 filt_ret: 1739 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1740 } 1741 1742 static void 1743 init_dag(Obj_Entry *root) 1744 { 1745 const Needed_Entry *needed; 1746 const Objlist_Entry *elm; 1747 DoneList donelist; 1748 1749 if (root->dag_inited) 1750 return; 1751 donelist_init(&donelist); 1752 1753 /* Root object belongs to own DAG. */ 1754 objlist_push_tail(&root->dldags, root); 1755 objlist_push_tail(&root->dagmembers, root); 1756 donelist_check(&donelist, root); 1757 1758 /* 1759 * Add dependencies of root object to DAG in breadth order 1760 * by exploiting the fact that each new object get added 1761 * to the tail of the dagmembers list. 1762 */ 1763 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1764 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1765 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1766 continue; 1767 objlist_push_tail(&needed->obj->dldags, root); 1768 objlist_push_tail(&root->dagmembers, needed->obj); 1769 } 1770 } 1771 root->dag_inited = true; 1772 } 1773 1774 static void 1775 process_nodelete(Obj_Entry *root) 1776 { 1777 const Objlist_Entry *elm; 1778 1779 /* 1780 * Walk over object DAG and process every dependent object that 1781 * is marked as DF_1_NODELETE. They need to grow their own DAG, 1782 * which then should have its reference upped separately. 1783 */ 1784 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1785 if (elm->obj != NULL && elm->obj->z_nodelete && 1786 !elm->obj->ref_nodel) { 1787 dbg("obj %s nodelete", elm->obj->path); 1788 init_dag(elm->obj); 1789 ref_dag(elm->obj); 1790 elm->obj->ref_nodel = true; 1791 } 1792 } 1793 } 1794 /* 1795 * Initialize the dynamic linker. The argument is the address at which 1796 * the dynamic linker has been mapped into memory. The primary task of 1797 * this function is to relocate the dynamic linker. 1798 */ 1799 static void 1800 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 1801 { 1802 Obj_Entry objtmp; /* Temporary rtld object */ 1803 const Elf_Dyn *dyn_rpath; 1804 const Elf_Dyn *dyn_soname; 1805 const Elf_Dyn *dyn_runpath; 1806 1807 #ifdef RTLD_INIT_PAGESIZES_EARLY 1808 /* The page size is required by the dynamic memory allocator. */ 1809 init_pagesizes(aux_info); 1810 #endif 1811 1812 /* 1813 * Conjure up an Obj_Entry structure for the dynamic linker. 1814 * 1815 * The "path" member can't be initialized yet because string constants 1816 * cannot yet be accessed. Below we will set it correctly. 1817 */ 1818 memset(&objtmp, 0, sizeof(objtmp)); 1819 objtmp.path = NULL; 1820 objtmp.rtld = true; 1821 objtmp.mapbase = mapbase; 1822 #ifdef PIC 1823 objtmp.relocbase = mapbase; 1824 #endif 1825 if (RTLD_IS_DYNAMIC()) { 1826 objtmp.dynamic = rtld_dynamic(&objtmp); 1827 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 1828 assert(objtmp.needed == NULL); 1829 #if !defined(__mips__) 1830 /* MIPS has a bogus DT_TEXTREL. */ 1831 assert(!objtmp.textrel); 1832 #endif 1833 1834 /* 1835 * Temporarily put the dynamic linker entry into the object list, so 1836 * that symbols can be found. 1837 */ 1838 1839 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 1840 } 1841 1842 /* Initialize the object list. */ 1843 obj_tail = &obj_list; 1844 1845 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1846 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1847 1848 #ifndef RTLD_INIT_PAGESIZES_EARLY 1849 /* The page size is required by the dynamic memory allocator. */ 1850 init_pagesizes(aux_info); 1851 #endif 1852 1853 if (aux_info[AT_OSRELDATE] != NULL) 1854 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 1855 1856 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 1857 1858 /* Replace the path with a dynamically allocated copy. */ 1859 obj_rtld.path = xstrdup(PATH_RTLD); 1860 1861 r_debug.r_brk = r_debug_state; 1862 r_debug.r_state = RT_CONSISTENT; 1863 } 1864 1865 /* 1866 * Retrieve the array of supported page sizes. The kernel provides the page 1867 * sizes in increasing order. 1868 */ 1869 static void 1870 init_pagesizes(Elf_Auxinfo **aux_info) 1871 { 1872 static size_t psa[MAXPAGESIZES]; 1873 int mib[2]; 1874 size_t len, size; 1875 1876 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 1877 NULL) { 1878 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 1879 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 1880 } else { 1881 len = 2; 1882 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 1883 size = sizeof(psa); 1884 else { 1885 /* As a fallback, retrieve the base page size. */ 1886 size = sizeof(psa[0]); 1887 if (aux_info[AT_PAGESZ] != NULL) { 1888 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 1889 goto psa_filled; 1890 } else { 1891 mib[0] = CTL_HW; 1892 mib[1] = HW_PAGESIZE; 1893 len = 2; 1894 } 1895 } 1896 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 1897 _rtld_error("sysctl for hw.pagesize(s) failed"); 1898 die(); 1899 } 1900 psa_filled: 1901 pagesizes = psa; 1902 } 1903 npagesizes = size / sizeof(pagesizes[0]); 1904 /* Discard any invalid entries at the end of the array. */ 1905 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 1906 npagesizes--; 1907 } 1908 1909 /* 1910 * Add the init functions from a needed object list (and its recursive 1911 * needed objects) to "list". This is not used directly; it is a helper 1912 * function for initlist_add_objects(). The write lock must be held 1913 * when this function is called. 1914 */ 1915 static void 1916 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 1917 { 1918 /* Recursively process the successor needed objects. */ 1919 if (needed->next != NULL) 1920 initlist_add_neededs(needed->next, list); 1921 1922 /* Process the current needed object. */ 1923 if (needed->obj != NULL) 1924 initlist_add_objects(needed->obj, &needed->obj->next, list); 1925 } 1926 1927 /* 1928 * Scan all of the DAGs rooted in the range of objects from "obj" to 1929 * "tail" and add their init functions to "list". This recurses over 1930 * the DAGs and ensure the proper init ordering such that each object's 1931 * needed libraries are initialized before the object itself. At the 1932 * same time, this function adds the objects to the global finalization 1933 * list "list_fini" in the opposite order. The write lock must be 1934 * held when this function is called. 1935 */ 1936 static void 1937 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list) 1938 { 1939 1940 if (obj->init_scanned || obj->init_done) 1941 return; 1942 obj->init_scanned = true; 1943 1944 /* Recursively process the successor objects. */ 1945 if (&obj->next != tail) 1946 initlist_add_objects(obj->next, tail, list); 1947 1948 /* Recursively process the needed objects. */ 1949 if (obj->needed != NULL) 1950 initlist_add_neededs(obj->needed, list); 1951 if (obj->needed_filtees != NULL) 1952 initlist_add_neededs(obj->needed_filtees, list); 1953 if (obj->needed_aux_filtees != NULL) 1954 initlist_add_neededs(obj->needed_aux_filtees, list); 1955 1956 /* Add the object to the init list. */ 1957 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL || 1958 obj->init_array != (Elf_Addr)NULL) 1959 objlist_push_tail(list, obj); 1960 1961 /* Add the object to the global fini list in the reverse order. */ 1962 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 1963 && !obj->on_fini_list) { 1964 objlist_push_head(&list_fini, obj); 1965 obj->on_fini_list = true; 1966 } 1967 } 1968 1969 #ifndef FPTR_TARGET 1970 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 1971 #endif 1972 1973 static void 1974 free_needed_filtees(Needed_Entry *n) 1975 { 1976 Needed_Entry *needed, *needed1; 1977 1978 for (needed = n; needed != NULL; needed = needed->next) { 1979 if (needed->obj != NULL) { 1980 dlclose(needed->obj); 1981 needed->obj = NULL; 1982 } 1983 } 1984 for (needed = n; needed != NULL; needed = needed1) { 1985 needed1 = needed->next; 1986 free(needed); 1987 } 1988 } 1989 1990 static void 1991 unload_filtees(Obj_Entry *obj) 1992 { 1993 1994 free_needed_filtees(obj->needed_filtees); 1995 obj->needed_filtees = NULL; 1996 free_needed_filtees(obj->needed_aux_filtees); 1997 obj->needed_aux_filtees = NULL; 1998 obj->filtees_loaded = false; 1999 } 2000 2001 static void 2002 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2003 RtldLockState *lockstate) 2004 { 2005 2006 for (; needed != NULL; needed = needed->next) { 2007 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2008 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2009 RTLD_LOCAL, lockstate); 2010 } 2011 } 2012 2013 static void 2014 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2015 { 2016 2017 lock_restart_for_upgrade(lockstate); 2018 if (!obj->filtees_loaded) { 2019 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2020 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2021 obj->filtees_loaded = true; 2022 } 2023 } 2024 2025 static int 2026 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2027 { 2028 Obj_Entry *obj1; 2029 2030 for (; needed != NULL; needed = needed->next) { 2031 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2032 flags & ~RTLD_LO_NOLOAD); 2033 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2034 return (-1); 2035 } 2036 return (0); 2037 } 2038 2039 /* 2040 * Given a shared object, traverse its list of needed objects, and load 2041 * each of them. Returns 0 on success. Generates an error message and 2042 * returns -1 on failure. 2043 */ 2044 static int 2045 load_needed_objects(Obj_Entry *first, int flags) 2046 { 2047 Obj_Entry *obj; 2048 2049 for (obj = first; obj != NULL; obj = obj->next) { 2050 if (process_needed(obj, obj->needed, flags) == -1) 2051 return (-1); 2052 } 2053 return (0); 2054 } 2055 2056 static int 2057 load_preload_objects(void) 2058 { 2059 char *p = ld_preload; 2060 Obj_Entry *obj; 2061 static const char delim[] = " \t:;"; 2062 2063 if (p == NULL) 2064 return 0; 2065 2066 p += strspn(p, delim); 2067 while (*p != '\0') { 2068 size_t len = strcspn(p, delim); 2069 char savech; 2070 2071 savech = p[len]; 2072 p[len] = '\0'; 2073 obj = load_object(p, -1, NULL, 0); 2074 if (obj == NULL) 2075 return -1; /* XXX - cleanup */ 2076 obj->z_interpose = true; 2077 p[len] = savech; 2078 p += len; 2079 p += strspn(p, delim); 2080 } 2081 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2082 return 0; 2083 } 2084 2085 static const char * 2086 printable_path(const char *path) 2087 { 2088 2089 return (path == NULL ? "<unknown>" : path); 2090 } 2091 2092 /* 2093 * Load a shared object into memory, if it is not already loaded. The 2094 * object may be specified by name or by user-supplied file descriptor 2095 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2096 * duplicate is. 2097 * 2098 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2099 * on failure. 2100 */ 2101 static Obj_Entry * 2102 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2103 { 2104 Obj_Entry *obj; 2105 int fd; 2106 struct stat sb; 2107 char *path; 2108 2109 fd = -1; 2110 if (name != NULL) { 2111 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 2112 if (object_match_name(obj, name)) 2113 return (obj); 2114 } 2115 2116 path = find_library(name, refobj, &fd); 2117 if (path == NULL) 2118 return (NULL); 2119 } else 2120 path = NULL; 2121 2122 if (fd >= 0) { 2123 /* 2124 * search_library_pathfds() opens a fresh file descriptor for the 2125 * library, so there is no need to dup(). 2126 */ 2127 } else if (fd_u == -1) { 2128 /* 2129 * If we didn't find a match by pathname, or the name is not 2130 * supplied, open the file and check again by device and inode. 2131 * This avoids false mismatches caused by multiple links or ".." 2132 * in pathnames. 2133 * 2134 * To avoid a race, we open the file and use fstat() rather than 2135 * using stat(). 2136 */ 2137 if ((fd = open(path, O_RDONLY | O_CLOEXEC)) == -1) { 2138 _rtld_error("Cannot open \"%s\"", path); 2139 free(path); 2140 return (NULL); 2141 } 2142 } else { 2143 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2144 if (fd == -1) { 2145 _rtld_error("Cannot dup fd"); 2146 free(path); 2147 return (NULL); 2148 } 2149 } 2150 if (fstat(fd, &sb) == -1) { 2151 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2152 close(fd); 2153 free(path); 2154 return NULL; 2155 } 2156 for (obj = obj_list->next; obj != NULL; obj = obj->next) 2157 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2158 break; 2159 if (obj != NULL && name != NULL) { 2160 object_add_name(obj, name); 2161 free(path); 2162 close(fd); 2163 return obj; 2164 } 2165 if (flags & RTLD_LO_NOLOAD) { 2166 free(path); 2167 close(fd); 2168 return (NULL); 2169 } 2170 2171 /* First use of this object, so we must map it in */ 2172 obj = do_load_object(fd, name, path, &sb, flags); 2173 if (obj == NULL) 2174 free(path); 2175 close(fd); 2176 2177 return obj; 2178 } 2179 2180 static Obj_Entry * 2181 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2182 int flags) 2183 { 2184 Obj_Entry *obj; 2185 struct statfs fs; 2186 2187 /* 2188 * but first, make sure that environment variables haven't been 2189 * used to circumvent the noexec flag on a filesystem. 2190 */ 2191 if (dangerous_ld_env) { 2192 if (fstatfs(fd, &fs) != 0) { 2193 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2194 return NULL; 2195 } 2196 if (fs.f_flags & MNT_NOEXEC) { 2197 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 2198 return NULL; 2199 } 2200 } 2201 dbg("loading \"%s\"", printable_path(path)); 2202 obj = map_object(fd, printable_path(path), sbp); 2203 if (obj == NULL) 2204 return NULL; 2205 2206 /* 2207 * If DT_SONAME is present in the object, digest_dynamic2 already 2208 * added it to the object names. 2209 */ 2210 if (name != NULL) 2211 object_add_name(obj, name); 2212 obj->path = path; 2213 digest_dynamic(obj, 0); 2214 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2215 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2216 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2217 RTLD_LO_DLOPEN) { 2218 dbg("refusing to load non-loadable \"%s\"", obj->path); 2219 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2220 munmap(obj->mapbase, obj->mapsize); 2221 obj_free(obj); 2222 return (NULL); 2223 } 2224 2225 *obj_tail = obj; 2226 obj_tail = &obj->next; 2227 obj_count++; 2228 obj_loads++; 2229 linkmap_add(obj); /* for GDB & dlinfo() */ 2230 max_stack_flags |= obj->stack_flags; 2231 2232 dbg(" %p .. %p: %s", obj->mapbase, 2233 obj->mapbase + obj->mapsize - 1, obj->path); 2234 if (obj->textrel) 2235 dbg(" WARNING: %s has impure text", obj->path); 2236 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2237 obj->path); 2238 2239 return obj; 2240 } 2241 2242 static Obj_Entry * 2243 obj_from_addr(const void *addr) 2244 { 2245 Obj_Entry *obj; 2246 2247 for (obj = obj_list; obj != NULL; obj = obj->next) { 2248 if (addr < (void *) obj->mapbase) 2249 continue; 2250 if (addr < (void *) (obj->mapbase + obj->mapsize)) 2251 return obj; 2252 } 2253 return NULL; 2254 } 2255 2256 static void 2257 preinit_main(void) 2258 { 2259 Elf_Addr *preinit_addr; 2260 int index; 2261 2262 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2263 if (preinit_addr == NULL) 2264 return; 2265 2266 for (index = 0; index < obj_main->preinit_array_num; index++) { 2267 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2268 dbg("calling preinit function for %s at %p", obj_main->path, 2269 (void *)preinit_addr[index]); 2270 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2271 0, 0, obj_main->path); 2272 call_init_pointer(obj_main, preinit_addr[index]); 2273 } 2274 } 2275 } 2276 2277 /* 2278 * Call the finalization functions for each of the objects in "list" 2279 * belonging to the DAG of "root" and referenced once. If NULL "root" 2280 * is specified, every finalization function will be called regardless 2281 * of the reference count and the list elements won't be freed. All of 2282 * the objects are expected to have non-NULL fini functions. 2283 */ 2284 static void 2285 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2286 { 2287 Objlist_Entry *elm; 2288 char *saved_msg; 2289 Elf_Addr *fini_addr; 2290 int index; 2291 2292 assert(root == NULL || root->refcount == 1); 2293 2294 /* 2295 * Preserve the current error message since a fini function might 2296 * call into the dynamic linker and overwrite it. 2297 */ 2298 saved_msg = errmsg_save(); 2299 do { 2300 STAILQ_FOREACH(elm, list, link) { 2301 if (root != NULL && (elm->obj->refcount != 1 || 2302 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2303 continue; 2304 /* Remove object from fini list to prevent recursive invocation. */ 2305 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2306 /* 2307 * XXX: If a dlopen() call references an object while the 2308 * fini function is in progress, we might end up trying to 2309 * unload the referenced object in dlclose() or the object 2310 * won't be unloaded although its fini function has been 2311 * called. 2312 */ 2313 lock_release(rtld_bind_lock, lockstate); 2314 2315 /* 2316 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2317 * When this happens, DT_FINI_ARRAY is processed first. 2318 */ 2319 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2320 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2321 for (index = elm->obj->fini_array_num - 1; index >= 0; 2322 index--) { 2323 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2324 dbg("calling fini function for %s at %p", 2325 elm->obj->path, (void *)fini_addr[index]); 2326 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2327 (void *)fini_addr[index], 0, 0, elm->obj->path); 2328 call_initfini_pointer(elm->obj, fini_addr[index]); 2329 } 2330 } 2331 } 2332 if (elm->obj->fini != (Elf_Addr)NULL) { 2333 dbg("calling fini function for %s at %p", elm->obj->path, 2334 (void *)elm->obj->fini); 2335 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2336 0, 0, elm->obj->path); 2337 call_initfini_pointer(elm->obj, elm->obj->fini); 2338 } 2339 wlock_acquire(rtld_bind_lock, lockstate); 2340 /* No need to free anything if process is going down. */ 2341 if (root != NULL) 2342 free(elm); 2343 /* 2344 * We must restart the list traversal after every fini call 2345 * because a dlclose() call from the fini function or from 2346 * another thread might have modified the reference counts. 2347 */ 2348 break; 2349 } 2350 } while (elm != NULL); 2351 errmsg_restore(saved_msg); 2352 } 2353 2354 /* 2355 * Call the initialization functions for each of the objects in 2356 * "list". All of the objects are expected to have non-NULL init 2357 * functions. 2358 */ 2359 static void 2360 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2361 { 2362 Objlist_Entry *elm; 2363 Obj_Entry *obj; 2364 char *saved_msg; 2365 Elf_Addr *init_addr; 2366 int index; 2367 2368 /* 2369 * Clean init_scanned flag so that objects can be rechecked and 2370 * possibly initialized earlier if any of vectors called below 2371 * cause the change by using dlopen. 2372 */ 2373 for (obj = obj_list; obj != NULL; obj = obj->next) 2374 obj->init_scanned = false; 2375 2376 /* 2377 * Preserve the current error message since an init function might 2378 * call into the dynamic linker and overwrite it. 2379 */ 2380 saved_msg = errmsg_save(); 2381 STAILQ_FOREACH(elm, list, link) { 2382 if (elm->obj->init_done) /* Initialized early. */ 2383 continue; 2384 /* 2385 * Race: other thread might try to use this object before current 2386 * one completes the initilization. Not much can be done here 2387 * without better locking. 2388 */ 2389 elm->obj->init_done = true; 2390 lock_release(rtld_bind_lock, lockstate); 2391 2392 /* 2393 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2394 * When this happens, DT_INIT is processed first. 2395 */ 2396 if (elm->obj->init != (Elf_Addr)NULL) { 2397 dbg("calling init function for %s at %p", elm->obj->path, 2398 (void *)elm->obj->init); 2399 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2400 0, 0, elm->obj->path); 2401 call_initfini_pointer(elm->obj, elm->obj->init); 2402 } 2403 init_addr = (Elf_Addr *)elm->obj->init_array; 2404 if (init_addr != NULL) { 2405 for (index = 0; index < elm->obj->init_array_num; index++) { 2406 if (init_addr[index] != 0 && init_addr[index] != 1) { 2407 dbg("calling init function for %s at %p", elm->obj->path, 2408 (void *)init_addr[index]); 2409 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2410 (void *)init_addr[index], 0, 0, elm->obj->path); 2411 call_init_pointer(elm->obj, init_addr[index]); 2412 } 2413 } 2414 } 2415 wlock_acquire(rtld_bind_lock, lockstate); 2416 } 2417 errmsg_restore(saved_msg); 2418 } 2419 2420 static void 2421 objlist_clear(Objlist *list) 2422 { 2423 Objlist_Entry *elm; 2424 2425 while (!STAILQ_EMPTY(list)) { 2426 elm = STAILQ_FIRST(list); 2427 STAILQ_REMOVE_HEAD(list, link); 2428 free(elm); 2429 } 2430 } 2431 2432 static Objlist_Entry * 2433 objlist_find(Objlist *list, const Obj_Entry *obj) 2434 { 2435 Objlist_Entry *elm; 2436 2437 STAILQ_FOREACH(elm, list, link) 2438 if (elm->obj == obj) 2439 return elm; 2440 return NULL; 2441 } 2442 2443 static void 2444 objlist_init(Objlist *list) 2445 { 2446 STAILQ_INIT(list); 2447 } 2448 2449 static void 2450 objlist_push_head(Objlist *list, Obj_Entry *obj) 2451 { 2452 Objlist_Entry *elm; 2453 2454 elm = NEW(Objlist_Entry); 2455 elm->obj = obj; 2456 STAILQ_INSERT_HEAD(list, elm, link); 2457 } 2458 2459 static void 2460 objlist_push_tail(Objlist *list, Obj_Entry *obj) 2461 { 2462 Objlist_Entry *elm; 2463 2464 elm = NEW(Objlist_Entry); 2465 elm->obj = obj; 2466 STAILQ_INSERT_TAIL(list, elm, link); 2467 } 2468 2469 static void 2470 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2471 { 2472 Objlist_Entry *elm, *listelm; 2473 2474 STAILQ_FOREACH(listelm, list, link) { 2475 if (listelm->obj == listobj) 2476 break; 2477 } 2478 elm = NEW(Objlist_Entry); 2479 elm->obj = obj; 2480 if (listelm != NULL) 2481 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2482 else 2483 STAILQ_INSERT_TAIL(list, elm, link); 2484 } 2485 2486 static void 2487 objlist_remove(Objlist *list, Obj_Entry *obj) 2488 { 2489 Objlist_Entry *elm; 2490 2491 if ((elm = objlist_find(list, obj)) != NULL) { 2492 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2493 free(elm); 2494 } 2495 } 2496 2497 /* 2498 * Relocate dag rooted in the specified object. 2499 * Returns 0 on success, or -1 on failure. 2500 */ 2501 2502 static int 2503 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2504 int flags, RtldLockState *lockstate) 2505 { 2506 Objlist_Entry *elm; 2507 int error; 2508 2509 error = 0; 2510 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2511 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2512 lockstate); 2513 if (error == -1) 2514 break; 2515 } 2516 return (error); 2517 } 2518 2519 /* 2520 * Relocate single object. 2521 * Returns 0 on success, or -1 on failure. 2522 */ 2523 static int 2524 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2525 int flags, RtldLockState *lockstate) 2526 { 2527 2528 if (obj->relocated) 2529 return (0); 2530 obj->relocated = true; 2531 if (obj != rtldobj) 2532 dbg("relocating \"%s\"", obj->path); 2533 2534 if (obj->symtab == NULL || obj->strtab == NULL || 2535 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2536 _rtld_error("%s: Shared object has no run-time symbol table", 2537 obj->path); 2538 return (-1); 2539 } 2540 2541 if (obj->textrel) { 2542 /* There are relocations to the write-protected text segment. */ 2543 if (mprotect(obj->mapbase, obj->textsize, 2544 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) { 2545 _rtld_error("%s: Cannot write-enable text segment: %s", 2546 obj->path, rtld_strerror(errno)); 2547 return (-1); 2548 } 2549 } 2550 2551 /* Process the non-PLT non-IFUNC relocations. */ 2552 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2553 return (-1); 2554 2555 if (obj->textrel) { /* Re-protected the text segment. */ 2556 if (mprotect(obj->mapbase, obj->textsize, 2557 PROT_READ|PROT_EXEC) == -1) { 2558 _rtld_error("%s: Cannot write-protect text segment: %s", 2559 obj->path, rtld_strerror(errno)); 2560 return (-1); 2561 } 2562 } 2563 2564 /* Set the special PLT or GOT entries. */ 2565 init_pltgot(obj); 2566 2567 /* Process the PLT relocations. */ 2568 if (reloc_plt(obj) == -1) 2569 return (-1); 2570 /* Relocate the jump slots if we are doing immediate binding. */ 2571 if (obj->bind_now || bind_now) 2572 if (reloc_jmpslots(obj, flags, lockstate) == -1) 2573 return (-1); 2574 2575 /* 2576 * Process the non-PLT IFUNC relocations. The relocations are 2577 * processed in two phases, because IFUNC resolvers may 2578 * reference other symbols, which must be readily processed 2579 * before resolvers are called. 2580 */ 2581 if (obj->non_plt_gnu_ifunc && 2582 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate)) 2583 return (-1); 2584 2585 if (obj->relro_size > 0) { 2586 if (mprotect(obj->relro_page, obj->relro_size, 2587 PROT_READ) == -1) { 2588 _rtld_error("%s: Cannot enforce relro protection: %s", 2589 obj->path, rtld_strerror(errno)); 2590 return (-1); 2591 } 2592 } 2593 2594 /* 2595 * Set up the magic number and version in the Obj_Entry. These 2596 * were checked in the crt1.o from the original ElfKit, so we 2597 * set them for backward compatibility. 2598 */ 2599 obj->magic = RTLD_MAGIC; 2600 obj->version = RTLD_VERSION; 2601 2602 return (0); 2603 } 2604 2605 /* 2606 * Relocate newly-loaded shared objects. The argument is a pointer to 2607 * the Obj_Entry for the first such object. All objects from the first 2608 * to the end of the list of objects are relocated. Returns 0 on success, 2609 * or -1 on failure. 2610 */ 2611 static int 2612 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2613 int flags, RtldLockState *lockstate) 2614 { 2615 Obj_Entry *obj; 2616 int error; 2617 2618 for (error = 0, obj = first; obj != NULL; obj = obj->next) { 2619 error = relocate_object(obj, bind_now, rtldobj, flags, 2620 lockstate); 2621 if (error == -1) 2622 break; 2623 } 2624 return (error); 2625 } 2626 2627 /* 2628 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2629 * referencing STT_GNU_IFUNC symbols is postponed till the other 2630 * relocations are done. The indirect functions specified as 2631 * ifunc are allowed to call other symbols, so we need to have 2632 * objects relocated before asking for resolution from indirects. 2633 * 2634 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2635 * instead of the usual lazy handling of PLT slots. It is 2636 * consistent with how GNU does it. 2637 */ 2638 static int 2639 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2640 RtldLockState *lockstate) 2641 { 2642 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2643 return (-1); 2644 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2645 reloc_gnu_ifunc(obj, flags, lockstate) == -1) 2646 return (-1); 2647 return (0); 2648 } 2649 2650 static int 2651 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags, 2652 RtldLockState *lockstate) 2653 { 2654 Obj_Entry *obj; 2655 2656 for (obj = first; obj != NULL; obj = obj->next) { 2657 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1) 2658 return (-1); 2659 } 2660 return (0); 2661 } 2662 2663 static int 2664 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2665 RtldLockState *lockstate) 2666 { 2667 Objlist_Entry *elm; 2668 2669 STAILQ_FOREACH(elm, list, link) { 2670 if (resolve_object_ifunc(elm->obj, bind_now, flags, 2671 lockstate) == -1) 2672 return (-1); 2673 } 2674 return (0); 2675 } 2676 2677 /* 2678 * Cleanup procedure. It will be called (by the atexit mechanism) just 2679 * before the process exits. 2680 */ 2681 static void 2682 rtld_exit(void) 2683 { 2684 RtldLockState lockstate; 2685 2686 wlock_acquire(rtld_bind_lock, &lockstate); 2687 dbg("rtld_exit()"); 2688 objlist_call_fini(&list_fini, NULL, &lockstate); 2689 /* No need to remove the items from the list, since we are exiting. */ 2690 if (!libmap_disable) 2691 lm_fini(); 2692 lock_release(rtld_bind_lock, &lockstate); 2693 } 2694 2695 /* 2696 * Iterate over a search path, translate each element, and invoke the 2697 * callback on the result. 2698 */ 2699 static void * 2700 path_enumerate(const char *path, path_enum_proc callback, void *arg) 2701 { 2702 const char *trans; 2703 if (path == NULL) 2704 return (NULL); 2705 2706 path += strspn(path, ":;"); 2707 while (*path != '\0') { 2708 size_t len; 2709 char *res; 2710 2711 len = strcspn(path, ":;"); 2712 trans = lm_findn(NULL, path, len); 2713 if (trans) 2714 res = callback(trans, strlen(trans), arg); 2715 else 2716 res = callback(path, len, arg); 2717 2718 if (res != NULL) 2719 return (res); 2720 2721 path += len; 2722 path += strspn(path, ":;"); 2723 } 2724 2725 return (NULL); 2726 } 2727 2728 struct try_library_args { 2729 const char *name; 2730 size_t namelen; 2731 char *buffer; 2732 size_t buflen; 2733 }; 2734 2735 static void * 2736 try_library_path(const char *dir, size_t dirlen, void *param) 2737 { 2738 struct try_library_args *arg; 2739 2740 arg = param; 2741 if (*dir == '/' || trust) { 2742 char *pathname; 2743 2744 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 2745 return (NULL); 2746 2747 pathname = arg->buffer; 2748 strncpy(pathname, dir, dirlen); 2749 pathname[dirlen] = '/'; 2750 strcpy(pathname + dirlen + 1, arg->name); 2751 2752 dbg(" Trying \"%s\"", pathname); 2753 if (access(pathname, F_OK) == 0) { /* We found it */ 2754 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 2755 strcpy(pathname, arg->buffer); 2756 return (pathname); 2757 } 2758 } 2759 return (NULL); 2760 } 2761 2762 static char * 2763 search_library_path(const char *name, const char *path) 2764 { 2765 char *p; 2766 struct try_library_args arg; 2767 2768 if (path == NULL) 2769 return NULL; 2770 2771 arg.name = name; 2772 arg.namelen = strlen(name); 2773 arg.buffer = xmalloc(PATH_MAX); 2774 arg.buflen = PATH_MAX; 2775 2776 p = path_enumerate(path, try_library_path, &arg); 2777 2778 free(arg.buffer); 2779 2780 return (p); 2781 } 2782 2783 2784 /* 2785 * Finds the library with the given name using the directory descriptors 2786 * listed in the LD_LIBRARY_PATH_FDS environment variable. 2787 * 2788 * Returns a freshly-opened close-on-exec file descriptor for the library, 2789 * or -1 if the library cannot be found. 2790 */ 2791 static char * 2792 search_library_pathfds(const char *name, const char *path, int *fdp) 2793 { 2794 char *envcopy, *fdstr, *found, *last_token; 2795 size_t len; 2796 int dirfd, fd; 2797 2798 dbg("%s('%s', '%s', fdp)", __func__, name, path); 2799 2800 /* Don't load from user-specified libdirs into setuid binaries. */ 2801 if (!trust) 2802 return (NULL); 2803 2804 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 2805 if (path == NULL) 2806 return (NULL); 2807 2808 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 2809 if (name[0] == '/') { 2810 dbg("Absolute path (%s) passed to %s", name, __func__); 2811 return (NULL); 2812 } 2813 2814 /* 2815 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 2816 * copy of the path, as strtok_r rewrites separator tokens 2817 * with '\0'. 2818 */ 2819 found = NULL; 2820 envcopy = xstrdup(path); 2821 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 2822 fdstr = strtok_r(NULL, ":", &last_token)) { 2823 dirfd = parse_libdir(fdstr); 2824 if (dirfd < 0) 2825 break; 2826 fd = openat(dirfd, name, O_RDONLY | O_CLOEXEC); 2827 if (fd >= 0) { 2828 *fdp = fd; 2829 len = strlen(fdstr) + strlen(name) + 3; 2830 found = xmalloc(len); 2831 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 2832 _rtld_error("error generating '%d/%s'", 2833 dirfd, name); 2834 die(); 2835 } 2836 dbg("open('%s') => %d", found, fd); 2837 break; 2838 } 2839 } 2840 free(envcopy); 2841 2842 return (found); 2843 } 2844 2845 2846 int 2847 dlclose(void *handle) 2848 { 2849 Obj_Entry *root; 2850 RtldLockState lockstate; 2851 2852 wlock_acquire(rtld_bind_lock, &lockstate); 2853 root = dlcheck(handle); 2854 if (root == NULL) { 2855 lock_release(rtld_bind_lock, &lockstate); 2856 return -1; 2857 } 2858 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 2859 root->path); 2860 2861 /* Unreference the object and its dependencies. */ 2862 root->dl_refcount--; 2863 2864 if (root->refcount == 1) { 2865 /* 2866 * The object will be no longer referenced, so we must unload it. 2867 * First, call the fini functions. 2868 */ 2869 objlist_call_fini(&list_fini, root, &lockstate); 2870 2871 unref_dag(root); 2872 2873 /* Finish cleaning up the newly-unreferenced objects. */ 2874 GDB_STATE(RT_DELETE,&root->linkmap); 2875 unload_object(root); 2876 GDB_STATE(RT_CONSISTENT,NULL); 2877 } else 2878 unref_dag(root); 2879 2880 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 2881 lock_release(rtld_bind_lock, &lockstate); 2882 return 0; 2883 } 2884 2885 char * 2886 dlerror(void) 2887 { 2888 char *msg = error_message; 2889 error_message = NULL; 2890 return msg; 2891 } 2892 2893 /* 2894 * This function is deprecated and has no effect. 2895 */ 2896 void 2897 dllockinit(void *context, 2898 void *(*lock_create)(void *context), 2899 void (*rlock_acquire)(void *lock), 2900 void (*wlock_acquire)(void *lock), 2901 void (*lock_release)(void *lock), 2902 void (*lock_destroy)(void *lock), 2903 void (*context_destroy)(void *context)) 2904 { 2905 static void *cur_context; 2906 static void (*cur_context_destroy)(void *); 2907 2908 /* Just destroy the context from the previous call, if necessary. */ 2909 if (cur_context_destroy != NULL) 2910 cur_context_destroy(cur_context); 2911 cur_context = context; 2912 cur_context_destroy = context_destroy; 2913 } 2914 2915 void * 2916 dlopen(const char *name, int mode) 2917 { 2918 2919 return (rtld_dlopen(name, -1, mode)); 2920 } 2921 2922 void * 2923 fdlopen(int fd, int mode) 2924 { 2925 2926 return (rtld_dlopen(NULL, fd, mode)); 2927 } 2928 2929 static void * 2930 rtld_dlopen(const char *name, int fd, int mode) 2931 { 2932 RtldLockState lockstate; 2933 int lo_flags; 2934 2935 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 2936 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 2937 if (ld_tracing != NULL) { 2938 rlock_acquire(rtld_bind_lock, &lockstate); 2939 if (sigsetjmp(lockstate.env, 0) != 0) 2940 lock_upgrade(rtld_bind_lock, &lockstate); 2941 environ = (char **)*get_program_var_addr("environ", &lockstate); 2942 lock_release(rtld_bind_lock, &lockstate); 2943 } 2944 lo_flags = RTLD_LO_DLOPEN; 2945 if (mode & RTLD_NODELETE) 2946 lo_flags |= RTLD_LO_NODELETE; 2947 if (mode & RTLD_NOLOAD) 2948 lo_flags |= RTLD_LO_NOLOAD; 2949 if (ld_tracing != NULL) 2950 lo_flags |= RTLD_LO_TRACE; 2951 2952 return (dlopen_object(name, fd, obj_main, lo_flags, 2953 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 2954 } 2955 2956 static void 2957 dlopen_cleanup(Obj_Entry *obj) 2958 { 2959 2960 obj->dl_refcount--; 2961 unref_dag(obj); 2962 if (obj->refcount == 0) 2963 unload_object(obj); 2964 } 2965 2966 static Obj_Entry * 2967 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 2968 int mode, RtldLockState *lockstate) 2969 { 2970 Obj_Entry **old_obj_tail; 2971 Obj_Entry *obj; 2972 Objlist initlist; 2973 RtldLockState mlockstate; 2974 int result; 2975 2976 objlist_init(&initlist); 2977 2978 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 2979 wlock_acquire(rtld_bind_lock, &mlockstate); 2980 lockstate = &mlockstate; 2981 } 2982 GDB_STATE(RT_ADD,NULL); 2983 2984 old_obj_tail = obj_tail; 2985 obj = NULL; 2986 if (name == NULL && fd == -1) { 2987 obj = obj_main; 2988 obj->refcount++; 2989 } else { 2990 obj = load_object(name, fd, refobj, lo_flags); 2991 } 2992 2993 if (obj) { 2994 obj->dl_refcount++; 2995 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 2996 objlist_push_tail(&list_global, obj); 2997 if (*old_obj_tail != NULL) { /* We loaded something new. */ 2998 assert(*old_obj_tail == obj); 2999 result = load_needed_objects(obj, 3000 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 3001 init_dag(obj); 3002 ref_dag(obj); 3003 if (result != -1) 3004 result = rtld_verify_versions(&obj->dagmembers); 3005 if (result != -1 && ld_tracing) 3006 goto trace; 3007 if (result == -1 || relocate_object_dag(obj, 3008 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3009 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3010 lockstate) == -1) { 3011 dlopen_cleanup(obj); 3012 obj = NULL; 3013 } else if (lo_flags & RTLD_LO_EARLY) { 3014 /* 3015 * Do not call the init functions for early loaded 3016 * filtees. The image is still not initialized enough 3017 * for them to work. 3018 * 3019 * Our object is found by the global object list and 3020 * will be ordered among all init calls done right 3021 * before transferring control to main. 3022 */ 3023 } else { 3024 /* Make list of init functions to call. */ 3025 initlist_add_objects(obj, &obj->next, &initlist); 3026 } 3027 /* 3028 * Process all no_delete objects here, given them own 3029 * DAGs to prevent their dependencies from being unloaded. 3030 * This has to be done after we have loaded all of the 3031 * dependencies, so that we do not miss any. 3032 */ 3033 if (obj != NULL) 3034 process_nodelete(obj); 3035 } else { 3036 /* 3037 * Bump the reference counts for objects on this DAG. If 3038 * this is the first dlopen() call for the object that was 3039 * already loaded as a dependency, initialize the dag 3040 * starting at it. 3041 */ 3042 init_dag(obj); 3043 ref_dag(obj); 3044 3045 if ((lo_flags & RTLD_LO_TRACE) != 0) 3046 goto trace; 3047 } 3048 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3049 obj->z_nodelete) && !obj->ref_nodel) { 3050 dbg("obj %s nodelete", obj->path); 3051 ref_dag(obj); 3052 obj->z_nodelete = obj->ref_nodel = true; 3053 } 3054 } 3055 3056 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3057 name); 3058 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3059 3060 if (!(lo_flags & RTLD_LO_EARLY)) { 3061 map_stacks_exec(lockstate); 3062 } 3063 3064 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3065 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3066 lockstate) == -1) { 3067 objlist_clear(&initlist); 3068 dlopen_cleanup(obj); 3069 if (lockstate == &mlockstate) 3070 lock_release(rtld_bind_lock, lockstate); 3071 return (NULL); 3072 } 3073 3074 if (!(lo_flags & RTLD_LO_EARLY)) { 3075 /* Call the init functions. */ 3076 objlist_call_init(&initlist, lockstate); 3077 } 3078 objlist_clear(&initlist); 3079 if (lockstate == &mlockstate) 3080 lock_release(rtld_bind_lock, lockstate); 3081 return obj; 3082 trace: 3083 trace_loaded_objects(obj); 3084 if (lockstate == &mlockstate) 3085 lock_release(rtld_bind_lock, lockstate); 3086 exit(0); 3087 } 3088 3089 static void * 3090 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3091 int flags) 3092 { 3093 DoneList donelist; 3094 const Obj_Entry *obj, *defobj; 3095 const Elf_Sym *def; 3096 SymLook req; 3097 RtldLockState lockstate; 3098 tls_index ti; 3099 int res; 3100 3101 def = NULL; 3102 defobj = NULL; 3103 symlook_init(&req, name); 3104 req.ventry = ve; 3105 req.flags = flags | SYMLOOK_IN_PLT; 3106 req.lockstate = &lockstate; 3107 3108 rlock_acquire(rtld_bind_lock, &lockstate); 3109 if (sigsetjmp(lockstate.env, 0) != 0) 3110 lock_upgrade(rtld_bind_lock, &lockstate); 3111 if (handle == NULL || handle == RTLD_NEXT || 3112 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3113 3114 if ((obj = obj_from_addr(retaddr)) == NULL) { 3115 _rtld_error("Cannot determine caller's shared object"); 3116 lock_release(rtld_bind_lock, &lockstate); 3117 return NULL; 3118 } 3119 if (handle == NULL) { /* Just the caller's shared object. */ 3120 res = symlook_obj(&req, obj); 3121 if (res == 0) { 3122 def = req.sym_out; 3123 defobj = req.defobj_out; 3124 } 3125 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3126 handle == RTLD_SELF) { /* ... caller included */ 3127 if (handle == RTLD_NEXT) 3128 obj = obj->next; 3129 for (; obj != NULL; obj = obj->next) { 3130 res = symlook_obj(&req, obj); 3131 if (res == 0) { 3132 if (def == NULL || 3133 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3134 def = req.sym_out; 3135 defobj = req.defobj_out; 3136 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3137 break; 3138 } 3139 } 3140 } 3141 /* 3142 * Search the dynamic linker itself, and possibly resolve the 3143 * symbol from there. This is how the application links to 3144 * dynamic linker services such as dlopen. 3145 */ 3146 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3147 res = symlook_obj(&req, &obj_rtld); 3148 if (res == 0) { 3149 def = req.sym_out; 3150 defobj = req.defobj_out; 3151 } 3152 } 3153 } else { 3154 assert(handle == RTLD_DEFAULT); 3155 res = symlook_default(&req, obj); 3156 if (res == 0) { 3157 defobj = req.defobj_out; 3158 def = req.sym_out; 3159 } 3160 } 3161 } else { 3162 if ((obj = dlcheck(handle)) == NULL) { 3163 lock_release(rtld_bind_lock, &lockstate); 3164 return NULL; 3165 } 3166 3167 donelist_init(&donelist); 3168 if (obj->mainprog) { 3169 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3170 res = symlook_global(&req, &donelist); 3171 if (res == 0) { 3172 def = req.sym_out; 3173 defobj = req.defobj_out; 3174 } 3175 /* 3176 * Search the dynamic linker itself, and possibly resolve the 3177 * symbol from there. This is how the application links to 3178 * dynamic linker services such as dlopen. 3179 */ 3180 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3181 res = symlook_obj(&req, &obj_rtld); 3182 if (res == 0) { 3183 def = req.sym_out; 3184 defobj = req.defobj_out; 3185 } 3186 } 3187 } 3188 else { 3189 /* Search the whole DAG rooted at the given object. */ 3190 res = symlook_list(&req, &obj->dagmembers, &donelist); 3191 if (res == 0) { 3192 def = req.sym_out; 3193 defobj = req.defobj_out; 3194 } 3195 } 3196 } 3197 3198 if (def != NULL) { 3199 lock_release(rtld_bind_lock, &lockstate); 3200 3201 /* 3202 * The value required by the caller is derived from the value 3203 * of the symbol. this is simply the relocated value of the 3204 * symbol. 3205 */ 3206 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3207 return (make_function_pointer(def, defobj)); 3208 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3209 return (rtld_resolve_ifunc(defobj, def)); 3210 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3211 ti.ti_module = defobj->tlsindex; 3212 ti.ti_offset = def->st_value; 3213 return (__tls_get_addr(&ti)); 3214 } else 3215 return (defobj->relocbase + def->st_value); 3216 } 3217 3218 _rtld_error("Undefined symbol \"%s\"", name); 3219 lock_release(rtld_bind_lock, &lockstate); 3220 return NULL; 3221 } 3222 3223 void * 3224 dlsym(void *handle, const char *name) 3225 { 3226 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3227 SYMLOOK_DLSYM); 3228 } 3229 3230 dlfunc_t 3231 dlfunc(void *handle, const char *name) 3232 { 3233 union { 3234 void *d; 3235 dlfunc_t f; 3236 } rv; 3237 3238 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3239 SYMLOOK_DLSYM); 3240 return (rv.f); 3241 } 3242 3243 void * 3244 dlvsym(void *handle, const char *name, const char *version) 3245 { 3246 Ver_Entry ventry; 3247 3248 ventry.name = version; 3249 ventry.file = NULL; 3250 ventry.hash = elf_hash(version); 3251 ventry.flags= 0; 3252 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3253 SYMLOOK_DLSYM); 3254 } 3255 3256 int 3257 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3258 { 3259 const Obj_Entry *obj; 3260 RtldLockState lockstate; 3261 3262 rlock_acquire(rtld_bind_lock, &lockstate); 3263 obj = obj_from_addr(addr); 3264 if (obj == NULL) { 3265 _rtld_error("No shared object contains address"); 3266 lock_release(rtld_bind_lock, &lockstate); 3267 return (0); 3268 } 3269 rtld_fill_dl_phdr_info(obj, phdr_info); 3270 lock_release(rtld_bind_lock, &lockstate); 3271 return (1); 3272 } 3273 3274 int 3275 dladdr(const void *addr, Dl_info *info) 3276 { 3277 const Obj_Entry *obj; 3278 const Elf_Sym *def; 3279 void *symbol_addr; 3280 unsigned long symoffset; 3281 RtldLockState lockstate; 3282 3283 rlock_acquire(rtld_bind_lock, &lockstate); 3284 obj = obj_from_addr(addr); 3285 if (obj == NULL) { 3286 _rtld_error("No shared object contains address"); 3287 lock_release(rtld_bind_lock, &lockstate); 3288 return 0; 3289 } 3290 info->dli_fname = obj->path; 3291 info->dli_fbase = obj->mapbase; 3292 info->dli_saddr = (void *)0; 3293 info->dli_sname = NULL; 3294 3295 /* 3296 * Walk the symbol list looking for the symbol whose address is 3297 * closest to the address sent in. 3298 */ 3299 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3300 def = obj->symtab + symoffset; 3301 3302 /* 3303 * For skip the symbol if st_shndx is either SHN_UNDEF or 3304 * SHN_COMMON. 3305 */ 3306 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3307 continue; 3308 3309 /* 3310 * If the symbol is greater than the specified address, or if it 3311 * is further away from addr than the current nearest symbol, 3312 * then reject it. 3313 */ 3314 symbol_addr = obj->relocbase + def->st_value; 3315 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3316 continue; 3317 3318 /* Update our idea of the nearest symbol. */ 3319 info->dli_sname = obj->strtab + def->st_name; 3320 info->dli_saddr = symbol_addr; 3321 3322 /* Exact match? */ 3323 if (info->dli_saddr == addr) 3324 break; 3325 } 3326 lock_release(rtld_bind_lock, &lockstate); 3327 return 1; 3328 } 3329 3330 int 3331 dlinfo(void *handle, int request, void *p) 3332 { 3333 const Obj_Entry *obj; 3334 RtldLockState lockstate; 3335 int error; 3336 3337 rlock_acquire(rtld_bind_lock, &lockstate); 3338 3339 if (handle == NULL || handle == RTLD_SELF) { 3340 void *retaddr; 3341 3342 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3343 if ((obj = obj_from_addr(retaddr)) == NULL) 3344 _rtld_error("Cannot determine caller's shared object"); 3345 } else 3346 obj = dlcheck(handle); 3347 3348 if (obj == NULL) { 3349 lock_release(rtld_bind_lock, &lockstate); 3350 return (-1); 3351 } 3352 3353 error = 0; 3354 switch (request) { 3355 case RTLD_DI_LINKMAP: 3356 *((struct link_map const **)p) = &obj->linkmap; 3357 break; 3358 case RTLD_DI_ORIGIN: 3359 error = rtld_dirname(obj->path, p); 3360 break; 3361 3362 case RTLD_DI_SERINFOSIZE: 3363 case RTLD_DI_SERINFO: 3364 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3365 break; 3366 3367 default: 3368 _rtld_error("Invalid request %d passed to dlinfo()", request); 3369 error = -1; 3370 } 3371 3372 lock_release(rtld_bind_lock, &lockstate); 3373 3374 return (error); 3375 } 3376 3377 static void 3378 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3379 { 3380 3381 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3382 phdr_info->dlpi_name = obj->path; 3383 phdr_info->dlpi_phdr = obj->phdr; 3384 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3385 phdr_info->dlpi_tls_modid = obj->tlsindex; 3386 phdr_info->dlpi_tls_data = obj->tlsinit; 3387 phdr_info->dlpi_adds = obj_loads; 3388 phdr_info->dlpi_subs = obj_loads - obj_count; 3389 } 3390 3391 int 3392 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3393 { 3394 struct dl_phdr_info phdr_info; 3395 const Obj_Entry *obj; 3396 RtldLockState bind_lockstate, phdr_lockstate; 3397 int error; 3398 3399 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3400 rlock_acquire(rtld_bind_lock, &bind_lockstate); 3401 3402 error = 0; 3403 3404 for (obj = obj_list; obj != NULL; obj = obj->next) { 3405 rtld_fill_dl_phdr_info(obj, &phdr_info); 3406 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0) 3407 break; 3408 3409 } 3410 if (error == 0) { 3411 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3412 error = callback(&phdr_info, sizeof(phdr_info), param); 3413 } 3414 3415 lock_release(rtld_bind_lock, &bind_lockstate); 3416 lock_release(rtld_phdr_lock, &phdr_lockstate); 3417 3418 return (error); 3419 } 3420 3421 static void * 3422 fill_search_info(const char *dir, size_t dirlen, void *param) 3423 { 3424 struct fill_search_info_args *arg; 3425 3426 arg = param; 3427 3428 if (arg->request == RTLD_DI_SERINFOSIZE) { 3429 arg->serinfo->dls_cnt ++; 3430 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3431 } else { 3432 struct dl_serpath *s_entry; 3433 3434 s_entry = arg->serpath; 3435 s_entry->dls_name = arg->strspace; 3436 s_entry->dls_flags = arg->flags; 3437 3438 strncpy(arg->strspace, dir, dirlen); 3439 arg->strspace[dirlen] = '\0'; 3440 3441 arg->strspace += dirlen + 1; 3442 arg->serpath++; 3443 } 3444 3445 return (NULL); 3446 } 3447 3448 static int 3449 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3450 { 3451 struct dl_serinfo _info; 3452 struct fill_search_info_args args; 3453 3454 args.request = RTLD_DI_SERINFOSIZE; 3455 args.serinfo = &_info; 3456 3457 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3458 _info.dls_cnt = 0; 3459 3460 path_enumerate(obj->rpath, fill_search_info, &args); 3461 path_enumerate(ld_library_path, fill_search_info, &args); 3462 path_enumerate(obj->runpath, fill_search_info, &args); 3463 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args); 3464 if (!obj->z_nodeflib) 3465 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 3466 3467 3468 if (request == RTLD_DI_SERINFOSIZE) { 3469 info->dls_size = _info.dls_size; 3470 info->dls_cnt = _info.dls_cnt; 3471 return (0); 3472 } 3473 3474 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3475 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3476 return (-1); 3477 } 3478 3479 args.request = RTLD_DI_SERINFO; 3480 args.serinfo = info; 3481 args.serpath = &info->dls_serpath[0]; 3482 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3483 3484 args.flags = LA_SER_RUNPATH; 3485 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 3486 return (-1); 3487 3488 args.flags = LA_SER_LIBPATH; 3489 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 3490 return (-1); 3491 3492 args.flags = LA_SER_RUNPATH; 3493 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL) 3494 return (-1); 3495 3496 args.flags = LA_SER_CONFIG; 3497 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args) 3498 != NULL) 3499 return (-1); 3500 3501 args.flags = LA_SER_DEFAULT; 3502 if (!obj->z_nodeflib && 3503 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 3504 return (-1); 3505 return (0); 3506 } 3507 3508 static int 3509 rtld_dirname(const char *path, char *bname) 3510 { 3511 const char *endp; 3512 3513 /* Empty or NULL string gets treated as "." */ 3514 if (path == NULL || *path == '\0') { 3515 bname[0] = '.'; 3516 bname[1] = '\0'; 3517 return (0); 3518 } 3519 3520 /* Strip trailing slashes */ 3521 endp = path + strlen(path) - 1; 3522 while (endp > path && *endp == '/') 3523 endp--; 3524 3525 /* Find the start of the dir */ 3526 while (endp > path && *endp != '/') 3527 endp--; 3528 3529 /* Either the dir is "/" or there are no slashes */ 3530 if (endp == path) { 3531 bname[0] = *endp == '/' ? '/' : '.'; 3532 bname[1] = '\0'; 3533 return (0); 3534 } else { 3535 do { 3536 endp--; 3537 } while (endp > path && *endp == '/'); 3538 } 3539 3540 if (endp - path + 2 > PATH_MAX) 3541 { 3542 _rtld_error("Filename is too long: %s", path); 3543 return(-1); 3544 } 3545 3546 strncpy(bname, path, endp - path + 1); 3547 bname[endp - path + 1] = '\0'; 3548 return (0); 3549 } 3550 3551 static int 3552 rtld_dirname_abs(const char *path, char *base) 3553 { 3554 char base_rel[PATH_MAX]; 3555 3556 if (rtld_dirname(path, base) == -1) 3557 return (-1); 3558 if (base[0] == '/') 3559 return (0); 3560 if (getcwd(base_rel, sizeof(base_rel)) == NULL || 3561 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) || 3562 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel)) 3563 return (-1); 3564 strcpy(base, base_rel); 3565 return (0); 3566 } 3567 3568 static void 3569 linkmap_add(Obj_Entry *obj) 3570 { 3571 struct link_map *l = &obj->linkmap; 3572 struct link_map *prev; 3573 3574 obj->linkmap.l_name = obj->path; 3575 obj->linkmap.l_addr = obj->mapbase; 3576 obj->linkmap.l_ld = obj->dynamic; 3577 #ifdef __mips__ 3578 /* GDB needs load offset on MIPS to use the symbols */ 3579 obj->linkmap.l_offs = obj->relocbase; 3580 #endif 3581 3582 if (r_debug.r_map == NULL) { 3583 r_debug.r_map = l; 3584 return; 3585 } 3586 3587 /* 3588 * Scan to the end of the list, but not past the entry for the 3589 * dynamic linker, which we want to keep at the very end. 3590 */ 3591 for (prev = r_debug.r_map; 3592 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3593 prev = prev->l_next) 3594 ; 3595 3596 /* Link in the new entry. */ 3597 l->l_prev = prev; 3598 l->l_next = prev->l_next; 3599 if (l->l_next != NULL) 3600 l->l_next->l_prev = l; 3601 prev->l_next = l; 3602 } 3603 3604 static void 3605 linkmap_delete(Obj_Entry *obj) 3606 { 3607 struct link_map *l = &obj->linkmap; 3608 3609 if (l->l_prev == NULL) { 3610 if ((r_debug.r_map = l->l_next) != NULL) 3611 l->l_next->l_prev = NULL; 3612 return; 3613 } 3614 3615 if ((l->l_prev->l_next = l->l_next) != NULL) 3616 l->l_next->l_prev = l->l_prev; 3617 } 3618 3619 /* 3620 * Function for the debugger to set a breakpoint on to gain control. 3621 * 3622 * The two parameters allow the debugger to easily find and determine 3623 * what the runtime loader is doing and to whom it is doing it. 3624 * 3625 * When the loadhook trap is hit (r_debug_state, set at program 3626 * initialization), the arguments can be found on the stack: 3627 * 3628 * +8 struct link_map *m 3629 * +4 struct r_debug *rd 3630 * +0 RetAddr 3631 */ 3632 void 3633 r_debug_state(struct r_debug* rd, struct link_map *m) 3634 { 3635 /* 3636 * The following is a hack to force the compiler to emit calls to 3637 * this function, even when optimizing. If the function is empty, 3638 * the compiler is not obliged to emit any code for calls to it, 3639 * even when marked __noinline. However, gdb depends on those 3640 * calls being made. 3641 */ 3642 __compiler_membar(); 3643 } 3644 3645 /* 3646 * A function called after init routines have completed. This can be used to 3647 * break before a program's entry routine is called, and can be used when 3648 * main is not available in the symbol table. 3649 */ 3650 void 3651 _r_debug_postinit(struct link_map *m) 3652 { 3653 3654 /* See r_debug_state(). */ 3655 __compiler_membar(); 3656 } 3657 3658 /* 3659 * Get address of the pointer variable in the main program. 3660 * Prefer non-weak symbol over the weak one. 3661 */ 3662 static const void ** 3663 get_program_var_addr(const char *name, RtldLockState *lockstate) 3664 { 3665 SymLook req; 3666 DoneList donelist; 3667 3668 symlook_init(&req, name); 3669 req.lockstate = lockstate; 3670 donelist_init(&donelist); 3671 if (symlook_global(&req, &donelist) != 0) 3672 return (NULL); 3673 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 3674 return ((const void **)make_function_pointer(req.sym_out, 3675 req.defobj_out)); 3676 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 3677 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 3678 else 3679 return ((const void **)(req.defobj_out->relocbase + 3680 req.sym_out->st_value)); 3681 } 3682 3683 /* 3684 * Set a pointer variable in the main program to the given value. This 3685 * is used to set key variables such as "environ" before any of the 3686 * init functions are called. 3687 */ 3688 static void 3689 set_program_var(const char *name, const void *value) 3690 { 3691 const void **addr; 3692 3693 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 3694 dbg("\"%s\": *%p <-- %p", name, addr, value); 3695 *addr = value; 3696 } 3697 } 3698 3699 /* 3700 * Search the global objects, including dependencies and main object, 3701 * for the given symbol. 3702 */ 3703 static int 3704 symlook_global(SymLook *req, DoneList *donelist) 3705 { 3706 SymLook req1; 3707 const Objlist_Entry *elm; 3708 int res; 3709 3710 symlook_init_from_req(&req1, req); 3711 3712 /* Search all objects loaded at program start up. */ 3713 if (req->defobj_out == NULL || 3714 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3715 res = symlook_list(&req1, &list_main, donelist); 3716 if (res == 0 && (req->defobj_out == NULL || 3717 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3718 req->sym_out = req1.sym_out; 3719 req->defobj_out = req1.defobj_out; 3720 assert(req->defobj_out != NULL); 3721 } 3722 } 3723 3724 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 3725 STAILQ_FOREACH(elm, &list_global, link) { 3726 if (req->defobj_out != NULL && 3727 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3728 break; 3729 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 3730 if (res == 0 && (req->defobj_out == NULL || 3731 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3732 req->sym_out = req1.sym_out; 3733 req->defobj_out = req1.defobj_out; 3734 assert(req->defobj_out != NULL); 3735 } 3736 } 3737 3738 return (req->sym_out != NULL ? 0 : ESRCH); 3739 } 3740 3741 /* 3742 * Given a symbol name in a referencing object, find the corresponding 3743 * definition of the symbol. Returns a pointer to the symbol, or NULL if 3744 * no definition was found. Returns a pointer to the Obj_Entry of the 3745 * defining object via the reference parameter DEFOBJ_OUT. 3746 */ 3747 static int 3748 symlook_default(SymLook *req, const Obj_Entry *refobj) 3749 { 3750 DoneList donelist; 3751 const Objlist_Entry *elm; 3752 SymLook req1; 3753 int res; 3754 3755 donelist_init(&donelist); 3756 symlook_init_from_req(&req1, req); 3757 3758 /* Look first in the referencing object if linked symbolically. */ 3759 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 3760 res = symlook_obj(&req1, refobj); 3761 if (res == 0) { 3762 req->sym_out = req1.sym_out; 3763 req->defobj_out = req1.defobj_out; 3764 assert(req->defobj_out != NULL); 3765 } 3766 } 3767 3768 symlook_global(req, &donelist); 3769 3770 /* Search all dlopened DAGs containing the referencing object. */ 3771 STAILQ_FOREACH(elm, &refobj->dldags, link) { 3772 if (req->sym_out != NULL && 3773 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3774 break; 3775 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 3776 if (res == 0 && (req->sym_out == NULL || 3777 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3778 req->sym_out = req1.sym_out; 3779 req->defobj_out = req1.defobj_out; 3780 assert(req->defobj_out != NULL); 3781 } 3782 } 3783 3784 /* 3785 * Search the dynamic linker itself, and possibly resolve the 3786 * symbol from there. This is how the application links to 3787 * dynamic linker services such as dlopen. 3788 */ 3789 if (req->sym_out == NULL || 3790 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3791 res = symlook_obj(&req1, &obj_rtld); 3792 if (res == 0) { 3793 req->sym_out = req1.sym_out; 3794 req->defobj_out = req1.defobj_out; 3795 assert(req->defobj_out != NULL); 3796 } 3797 } 3798 3799 return (req->sym_out != NULL ? 0 : ESRCH); 3800 } 3801 3802 static int 3803 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 3804 { 3805 const Elf_Sym *def; 3806 const Obj_Entry *defobj; 3807 const Objlist_Entry *elm; 3808 SymLook req1; 3809 int res; 3810 3811 def = NULL; 3812 defobj = NULL; 3813 STAILQ_FOREACH(elm, objlist, link) { 3814 if (donelist_check(dlp, elm->obj)) 3815 continue; 3816 symlook_init_from_req(&req1, req); 3817 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 3818 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3819 def = req1.sym_out; 3820 defobj = req1.defobj_out; 3821 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3822 break; 3823 } 3824 } 3825 } 3826 if (def != NULL) { 3827 req->sym_out = def; 3828 req->defobj_out = defobj; 3829 return (0); 3830 } 3831 return (ESRCH); 3832 } 3833 3834 /* 3835 * Search the chain of DAGS cointed to by the given Needed_Entry 3836 * for a symbol of the given name. Each DAG is scanned completely 3837 * before advancing to the next one. Returns a pointer to the symbol, 3838 * or NULL if no definition was found. 3839 */ 3840 static int 3841 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 3842 { 3843 const Elf_Sym *def; 3844 const Needed_Entry *n; 3845 const Obj_Entry *defobj; 3846 SymLook req1; 3847 int res; 3848 3849 def = NULL; 3850 defobj = NULL; 3851 symlook_init_from_req(&req1, req); 3852 for (n = needed; n != NULL; n = n->next) { 3853 if (n->obj == NULL || 3854 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 3855 continue; 3856 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3857 def = req1.sym_out; 3858 defobj = req1.defobj_out; 3859 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3860 break; 3861 } 3862 } 3863 if (def != NULL) { 3864 req->sym_out = def; 3865 req->defobj_out = defobj; 3866 return (0); 3867 } 3868 return (ESRCH); 3869 } 3870 3871 /* 3872 * Search the symbol table of a single shared object for a symbol of 3873 * the given name and version, if requested. Returns a pointer to the 3874 * symbol, or NULL if no definition was found. If the object is 3875 * filter, return filtered symbol from filtee. 3876 * 3877 * The symbol's hash value is passed in for efficiency reasons; that 3878 * eliminates many recomputations of the hash value. 3879 */ 3880 int 3881 symlook_obj(SymLook *req, const Obj_Entry *obj) 3882 { 3883 DoneList donelist; 3884 SymLook req1; 3885 int flags, res, mres; 3886 3887 /* 3888 * If there is at least one valid hash at this point, we prefer to 3889 * use the faster GNU version if available. 3890 */ 3891 if (obj->valid_hash_gnu) 3892 mres = symlook_obj1_gnu(req, obj); 3893 else if (obj->valid_hash_sysv) 3894 mres = symlook_obj1_sysv(req, obj); 3895 else 3896 return (EINVAL); 3897 3898 if (mres == 0) { 3899 if (obj->needed_filtees != NULL) { 3900 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3901 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3902 donelist_init(&donelist); 3903 symlook_init_from_req(&req1, req); 3904 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 3905 if (res == 0) { 3906 req->sym_out = req1.sym_out; 3907 req->defobj_out = req1.defobj_out; 3908 } 3909 return (res); 3910 } 3911 if (obj->needed_aux_filtees != NULL) { 3912 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3913 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3914 donelist_init(&donelist); 3915 symlook_init_from_req(&req1, req); 3916 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 3917 if (res == 0) { 3918 req->sym_out = req1.sym_out; 3919 req->defobj_out = req1.defobj_out; 3920 return (res); 3921 } 3922 } 3923 } 3924 return (mres); 3925 } 3926 3927 /* Symbol match routine common to both hash functions */ 3928 static bool 3929 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 3930 const unsigned long symnum) 3931 { 3932 Elf_Versym verndx; 3933 const Elf_Sym *symp; 3934 const char *strp; 3935 3936 symp = obj->symtab + symnum; 3937 strp = obj->strtab + symp->st_name; 3938 3939 switch (ELF_ST_TYPE(symp->st_info)) { 3940 case STT_FUNC: 3941 case STT_NOTYPE: 3942 case STT_OBJECT: 3943 case STT_COMMON: 3944 case STT_GNU_IFUNC: 3945 if (symp->st_value == 0) 3946 return (false); 3947 /* fallthrough */ 3948 case STT_TLS: 3949 if (symp->st_shndx != SHN_UNDEF) 3950 break; 3951 #ifndef __mips__ 3952 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 3953 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 3954 break; 3955 /* fallthrough */ 3956 #endif 3957 default: 3958 return (false); 3959 } 3960 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 3961 return (false); 3962 3963 if (req->ventry == NULL) { 3964 if (obj->versyms != NULL) { 3965 verndx = VER_NDX(obj->versyms[symnum]); 3966 if (verndx > obj->vernum) { 3967 _rtld_error( 3968 "%s: symbol %s references wrong version %d", 3969 obj->path, obj->strtab + symnum, verndx); 3970 return (false); 3971 } 3972 /* 3973 * If we are not called from dlsym (i.e. this 3974 * is a normal relocation from unversioned 3975 * binary), accept the symbol immediately if 3976 * it happens to have first version after this 3977 * shared object became versioned. Otherwise, 3978 * if symbol is versioned and not hidden, 3979 * remember it. If it is the only symbol with 3980 * this name exported by the shared object, it 3981 * will be returned as a match by the calling 3982 * function. If symbol is global (verndx < 2) 3983 * accept it unconditionally. 3984 */ 3985 if ((req->flags & SYMLOOK_DLSYM) == 0 && 3986 verndx == VER_NDX_GIVEN) { 3987 result->sym_out = symp; 3988 return (true); 3989 } 3990 else if (verndx >= VER_NDX_GIVEN) { 3991 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 3992 == 0) { 3993 if (result->vsymp == NULL) 3994 result->vsymp = symp; 3995 result->vcount++; 3996 } 3997 return (false); 3998 } 3999 } 4000 result->sym_out = symp; 4001 return (true); 4002 } 4003 if (obj->versyms == NULL) { 4004 if (object_match_name(obj, req->ventry->name)) { 4005 _rtld_error("%s: object %s should provide version %s " 4006 "for symbol %s", obj_rtld.path, obj->path, 4007 req->ventry->name, obj->strtab + symnum); 4008 return (false); 4009 } 4010 } else { 4011 verndx = VER_NDX(obj->versyms[symnum]); 4012 if (verndx > obj->vernum) { 4013 _rtld_error("%s: symbol %s references wrong version %d", 4014 obj->path, obj->strtab + symnum, verndx); 4015 return (false); 4016 } 4017 if (obj->vertab[verndx].hash != req->ventry->hash || 4018 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4019 /* 4020 * Version does not match. Look if this is a 4021 * global symbol and if it is not hidden. If 4022 * global symbol (verndx < 2) is available, 4023 * use it. Do not return symbol if we are 4024 * called by dlvsym, because dlvsym looks for 4025 * a specific version and default one is not 4026 * what dlvsym wants. 4027 */ 4028 if ((req->flags & SYMLOOK_DLSYM) || 4029 (verndx >= VER_NDX_GIVEN) || 4030 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4031 return (false); 4032 } 4033 } 4034 result->sym_out = symp; 4035 return (true); 4036 } 4037 4038 /* 4039 * Search for symbol using SysV hash function. 4040 * obj->buckets is known not to be NULL at this point; the test for this was 4041 * performed with the obj->valid_hash_sysv assignment. 4042 */ 4043 static int 4044 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4045 { 4046 unsigned long symnum; 4047 Sym_Match_Result matchres; 4048 4049 matchres.sym_out = NULL; 4050 matchres.vsymp = NULL; 4051 matchres.vcount = 0; 4052 4053 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4054 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4055 if (symnum >= obj->nchains) 4056 return (ESRCH); /* Bad object */ 4057 4058 if (matched_symbol(req, obj, &matchres, symnum)) { 4059 req->sym_out = matchres.sym_out; 4060 req->defobj_out = obj; 4061 return (0); 4062 } 4063 } 4064 if (matchres.vcount == 1) { 4065 req->sym_out = matchres.vsymp; 4066 req->defobj_out = obj; 4067 return (0); 4068 } 4069 return (ESRCH); 4070 } 4071 4072 /* Search for symbol using GNU hash function */ 4073 static int 4074 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4075 { 4076 Elf_Addr bloom_word; 4077 const Elf32_Word *hashval; 4078 Elf32_Word bucket; 4079 Sym_Match_Result matchres; 4080 unsigned int h1, h2; 4081 unsigned long symnum; 4082 4083 matchres.sym_out = NULL; 4084 matchres.vsymp = NULL; 4085 matchres.vcount = 0; 4086 4087 /* Pick right bitmask word from Bloom filter array */ 4088 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4089 obj->maskwords_bm_gnu]; 4090 4091 /* Calculate modulus word size of gnu hash and its derivative */ 4092 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4093 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4094 4095 /* Filter out the "definitely not in set" queries */ 4096 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4097 return (ESRCH); 4098 4099 /* Locate hash chain and corresponding value element*/ 4100 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4101 if (bucket == 0) 4102 return (ESRCH); 4103 hashval = &obj->chain_zero_gnu[bucket]; 4104 do { 4105 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4106 symnum = hashval - obj->chain_zero_gnu; 4107 if (matched_symbol(req, obj, &matchres, symnum)) { 4108 req->sym_out = matchres.sym_out; 4109 req->defobj_out = obj; 4110 return (0); 4111 } 4112 } 4113 } while ((*hashval++ & 1) == 0); 4114 if (matchres.vcount == 1) { 4115 req->sym_out = matchres.vsymp; 4116 req->defobj_out = obj; 4117 return (0); 4118 } 4119 return (ESRCH); 4120 } 4121 4122 static void 4123 trace_loaded_objects(Obj_Entry *obj) 4124 { 4125 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4126 int c; 4127 4128 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 4129 main_local = ""; 4130 4131 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL) 4132 fmt1 = "\t%o => %p (%x)\n"; 4133 4134 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL) 4135 fmt2 = "\t%o (%x)\n"; 4136 4137 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL"); 4138 4139 for (; obj; obj = obj->next) { 4140 Needed_Entry *needed; 4141 char *name, *path; 4142 bool is_lib; 4143 4144 if (list_containers && obj->needed != NULL) 4145 rtld_printf("%s:\n", obj->path); 4146 for (needed = obj->needed; needed; needed = needed->next) { 4147 if (needed->obj != NULL) { 4148 if (needed->obj->traced && !list_containers) 4149 continue; 4150 needed->obj->traced = true; 4151 path = needed->obj->path; 4152 } else 4153 path = "not found"; 4154 4155 name = (char *)obj->strtab + needed->name; 4156 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4157 4158 fmt = is_lib ? fmt1 : fmt2; 4159 while ((c = *fmt++) != '\0') { 4160 switch (c) { 4161 default: 4162 rtld_putchar(c); 4163 continue; 4164 case '\\': 4165 switch (c = *fmt) { 4166 case '\0': 4167 continue; 4168 case 'n': 4169 rtld_putchar('\n'); 4170 break; 4171 case 't': 4172 rtld_putchar('\t'); 4173 break; 4174 } 4175 break; 4176 case '%': 4177 switch (c = *fmt) { 4178 case '\0': 4179 continue; 4180 case '%': 4181 default: 4182 rtld_putchar(c); 4183 break; 4184 case 'A': 4185 rtld_putstr(main_local); 4186 break; 4187 case 'a': 4188 rtld_putstr(obj_main->path); 4189 break; 4190 case 'o': 4191 rtld_putstr(name); 4192 break; 4193 #if 0 4194 case 'm': 4195 rtld_printf("%d", sodp->sod_major); 4196 break; 4197 case 'n': 4198 rtld_printf("%d", sodp->sod_minor); 4199 break; 4200 #endif 4201 case 'p': 4202 rtld_putstr(path); 4203 break; 4204 case 'x': 4205 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4206 0); 4207 break; 4208 } 4209 break; 4210 } 4211 ++fmt; 4212 } 4213 } 4214 } 4215 } 4216 4217 /* 4218 * Unload a dlopened object and its dependencies from memory and from 4219 * our data structures. It is assumed that the DAG rooted in the 4220 * object has already been unreferenced, and that the object has a 4221 * reference count of 0. 4222 */ 4223 static void 4224 unload_object(Obj_Entry *root) 4225 { 4226 Obj_Entry *obj; 4227 Obj_Entry **linkp; 4228 4229 assert(root->refcount == 0); 4230 4231 /* 4232 * Pass over the DAG removing unreferenced objects from 4233 * appropriate lists. 4234 */ 4235 unlink_object(root); 4236 4237 /* Unmap all objects that are no longer referenced. */ 4238 linkp = &obj_list->next; 4239 while ((obj = *linkp) != NULL) { 4240 if (obj->refcount == 0) { 4241 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 4242 obj->path); 4243 dbg("unloading \"%s\"", obj->path); 4244 unload_filtees(root); 4245 munmap(obj->mapbase, obj->mapsize); 4246 linkmap_delete(obj); 4247 *linkp = obj->next; 4248 obj_count--; 4249 obj_free(obj); 4250 } else 4251 linkp = &obj->next; 4252 } 4253 obj_tail = linkp; 4254 } 4255 4256 static void 4257 unlink_object(Obj_Entry *root) 4258 { 4259 Objlist_Entry *elm; 4260 4261 if (root->refcount == 0) { 4262 /* Remove the object from the RTLD_GLOBAL list. */ 4263 objlist_remove(&list_global, root); 4264 4265 /* Remove the object from all objects' DAG lists. */ 4266 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4267 objlist_remove(&elm->obj->dldags, root); 4268 if (elm->obj != root) 4269 unlink_object(elm->obj); 4270 } 4271 } 4272 } 4273 4274 static void 4275 ref_dag(Obj_Entry *root) 4276 { 4277 Objlist_Entry *elm; 4278 4279 assert(root->dag_inited); 4280 STAILQ_FOREACH(elm, &root->dagmembers, link) 4281 elm->obj->refcount++; 4282 } 4283 4284 static void 4285 unref_dag(Obj_Entry *root) 4286 { 4287 Objlist_Entry *elm; 4288 4289 assert(root->dag_inited); 4290 STAILQ_FOREACH(elm, &root->dagmembers, link) 4291 elm->obj->refcount--; 4292 } 4293 4294 /* 4295 * Common code for MD __tls_get_addr(). 4296 */ 4297 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4298 static void * 4299 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4300 { 4301 Elf_Addr *newdtv, *dtv; 4302 RtldLockState lockstate; 4303 int to_copy; 4304 4305 dtv = *dtvp; 4306 /* Check dtv generation in case new modules have arrived */ 4307 if (dtv[0] != tls_dtv_generation) { 4308 wlock_acquire(rtld_bind_lock, &lockstate); 4309 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4310 to_copy = dtv[1]; 4311 if (to_copy > tls_max_index) 4312 to_copy = tls_max_index; 4313 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4314 newdtv[0] = tls_dtv_generation; 4315 newdtv[1] = tls_max_index; 4316 free(dtv); 4317 lock_release(rtld_bind_lock, &lockstate); 4318 dtv = *dtvp = newdtv; 4319 } 4320 4321 /* Dynamically allocate module TLS if necessary */ 4322 if (dtv[index + 1] == 0) { 4323 /* Signal safe, wlock will block out signals. */ 4324 wlock_acquire(rtld_bind_lock, &lockstate); 4325 if (!dtv[index + 1]) 4326 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4327 lock_release(rtld_bind_lock, &lockstate); 4328 } 4329 return ((void *)(dtv[index + 1] + offset)); 4330 } 4331 4332 void * 4333 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4334 { 4335 Elf_Addr *dtv; 4336 4337 dtv = *dtvp; 4338 /* Check dtv generation in case new modules have arrived */ 4339 if (__predict_true(dtv[0] == tls_dtv_generation && 4340 dtv[index + 1] != 0)) 4341 return ((void *)(dtv[index + 1] + offset)); 4342 return (tls_get_addr_slow(dtvp, index, offset)); 4343 } 4344 4345 #if defined(__arm__) || defined(__mips__) || defined(__powerpc__) 4346 4347 /* 4348 * Allocate Static TLS using the Variant I method. 4349 */ 4350 void * 4351 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4352 { 4353 Obj_Entry *obj; 4354 char *tcb; 4355 Elf_Addr **tls; 4356 Elf_Addr *dtv; 4357 Elf_Addr addr; 4358 int i; 4359 4360 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4361 return (oldtcb); 4362 4363 assert(tcbsize >= TLS_TCB_SIZE); 4364 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 4365 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 4366 4367 if (oldtcb != NULL) { 4368 memcpy(tls, oldtcb, tls_static_space); 4369 free(oldtcb); 4370 4371 /* Adjust the DTV. */ 4372 dtv = tls[0]; 4373 for (i = 0; i < dtv[1]; i++) { 4374 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4375 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4376 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 4377 } 4378 } 4379 } else { 4380 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4381 tls[0] = dtv; 4382 dtv[0] = tls_dtv_generation; 4383 dtv[1] = tls_max_index; 4384 4385 for (obj = objs; obj; obj = obj->next) { 4386 if (obj->tlsoffset > 0) { 4387 addr = (Elf_Addr)tls + obj->tlsoffset; 4388 if (obj->tlsinitsize > 0) 4389 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4390 if (obj->tlssize > obj->tlsinitsize) 4391 memset((void*) (addr + obj->tlsinitsize), 0, 4392 obj->tlssize - obj->tlsinitsize); 4393 dtv[obj->tlsindex + 1] = addr; 4394 } 4395 } 4396 } 4397 4398 return (tcb); 4399 } 4400 4401 void 4402 free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4403 { 4404 Elf_Addr *dtv; 4405 Elf_Addr tlsstart, tlsend; 4406 int dtvsize, i; 4407 4408 assert(tcbsize >= TLS_TCB_SIZE); 4409 4410 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 4411 tlsend = tlsstart + tls_static_space; 4412 4413 dtv = *(Elf_Addr **)tlsstart; 4414 dtvsize = dtv[1]; 4415 for (i = 0; i < dtvsize; i++) { 4416 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4417 free((void*)dtv[i+2]); 4418 } 4419 } 4420 free(dtv); 4421 free(tcb); 4422 } 4423 4424 #endif 4425 4426 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 4427 4428 /* 4429 * Allocate Static TLS using the Variant II method. 4430 */ 4431 void * 4432 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4433 { 4434 Obj_Entry *obj; 4435 size_t size, ralign; 4436 char *tls; 4437 Elf_Addr *dtv, *olddtv; 4438 Elf_Addr segbase, oldsegbase, addr; 4439 int i; 4440 4441 ralign = tcbalign; 4442 if (tls_static_max_align > ralign) 4443 ralign = tls_static_max_align; 4444 size = round(tls_static_space, ralign) + round(tcbsize, ralign); 4445 4446 assert(tcbsize >= 2*sizeof(Elf_Addr)); 4447 tls = malloc_aligned(size, ralign); 4448 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4449 4450 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign)); 4451 ((Elf_Addr*)segbase)[0] = segbase; 4452 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 4453 4454 dtv[0] = tls_dtv_generation; 4455 dtv[1] = tls_max_index; 4456 4457 if (oldtls) { 4458 /* 4459 * Copy the static TLS block over whole. 4460 */ 4461 oldsegbase = (Elf_Addr) oldtls; 4462 memcpy((void *)(segbase - tls_static_space), 4463 (const void *)(oldsegbase - tls_static_space), 4464 tls_static_space); 4465 4466 /* 4467 * If any dynamic TLS blocks have been created tls_get_addr(), 4468 * move them over. 4469 */ 4470 olddtv = ((Elf_Addr**)oldsegbase)[1]; 4471 for (i = 0; i < olddtv[1]; i++) { 4472 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 4473 dtv[i+2] = olddtv[i+2]; 4474 olddtv[i+2] = 0; 4475 } 4476 } 4477 4478 /* 4479 * We assume that this block was the one we created with 4480 * allocate_initial_tls(). 4481 */ 4482 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 4483 } else { 4484 for (obj = objs; obj; obj = obj->next) { 4485 if (obj->tlsoffset) { 4486 addr = segbase - obj->tlsoffset; 4487 memset((void*) (addr + obj->tlsinitsize), 4488 0, obj->tlssize - obj->tlsinitsize); 4489 if (obj->tlsinit) 4490 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4491 dtv[obj->tlsindex + 1] = addr; 4492 } 4493 } 4494 } 4495 4496 return (void*) segbase; 4497 } 4498 4499 void 4500 free_tls(void *tls, size_t tcbsize, size_t tcbalign) 4501 { 4502 Elf_Addr* dtv; 4503 size_t size, ralign; 4504 int dtvsize, i; 4505 Elf_Addr tlsstart, tlsend; 4506 4507 /* 4508 * Figure out the size of the initial TLS block so that we can 4509 * find stuff which ___tls_get_addr() allocated dynamically. 4510 */ 4511 ralign = tcbalign; 4512 if (tls_static_max_align > ralign) 4513 ralign = tls_static_max_align; 4514 size = round(tls_static_space, ralign); 4515 4516 dtv = ((Elf_Addr**)tls)[1]; 4517 dtvsize = dtv[1]; 4518 tlsend = (Elf_Addr) tls; 4519 tlsstart = tlsend - size; 4520 for (i = 0; i < dtvsize; i++) { 4521 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 4522 free_aligned((void *)dtv[i + 2]); 4523 } 4524 } 4525 4526 free_aligned((void *)tlsstart); 4527 free((void*) dtv); 4528 } 4529 4530 #endif 4531 4532 /* 4533 * Allocate TLS block for module with given index. 4534 */ 4535 void * 4536 allocate_module_tls(int index) 4537 { 4538 Obj_Entry* obj; 4539 char* p; 4540 4541 for (obj = obj_list; obj; obj = obj->next) { 4542 if (obj->tlsindex == index) 4543 break; 4544 } 4545 if (!obj) { 4546 _rtld_error("Can't find module with TLS index %d", index); 4547 die(); 4548 } 4549 4550 p = malloc_aligned(obj->tlssize, obj->tlsalign); 4551 memcpy(p, obj->tlsinit, obj->tlsinitsize); 4552 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 4553 4554 return p; 4555 } 4556 4557 bool 4558 allocate_tls_offset(Obj_Entry *obj) 4559 { 4560 size_t off; 4561 4562 if (obj->tls_done) 4563 return true; 4564 4565 if (obj->tlssize == 0) { 4566 obj->tls_done = true; 4567 return true; 4568 } 4569 4570 if (obj->tlsindex == 1) 4571 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 4572 else 4573 off = calculate_tls_offset(tls_last_offset, tls_last_size, 4574 obj->tlssize, obj->tlsalign); 4575 4576 /* 4577 * If we have already fixed the size of the static TLS block, we 4578 * must stay within that size. When allocating the static TLS, we 4579 * leave a small amount of space spare to be used for dynamically 4580 * loading modules which use static TLS. 4581 */ 4582 if (tls_static_space != 0) { 4583 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 4584 return false; 4585 } else if (obj->tlsalign > tls_static_max_align) { 4586 tls_static_max_align = obj->tlsalign; 4587 } 4588 4589 tls_last_offset = obj->tlsoffset = off; 4590 tls_last_size = obj->tlssize; 4591 obj->tls_done = true; 4592 4593 return true; 4594 } 4595 4596 void 4597 free_tls_offset(Obj_Entry *obj) 4598 { 4599 4600 /* 4601 * If we were the last thing to allocate out of the static TLS 4602 * block, we give our space back to the 'allocator'. This is a 4603 * simplistic workaround to allow libGL.so.1 to be loaded and 4604 * unloaded multiple times. 4605 */ 4606 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 4607 == calculate_tls_end(tls_last_offset, tls_last_size)) { 4608 tls_last_offset -= obj->tlssize; 4609 tls_last_size = 0; 4610 } 4611 } 4612 4613 void * 4614 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 4615 { 4616 void *ret; 4617 RtldLockState lockstate; 4618 4619 wlock_acquire(rtld_bind_lock, &lockstate); 4620 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign); 4621 lock_release(rtld_bind_lock, &lockstate); 4622 return (ret); 4623 } 4624 4625 void 4626 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4627 { 4628 RtldLockState lockstate; 4629 4630 wlock_acquire(rtld_bind_lock, &lockstate); 4631 free_tls(tcb, tcbsize, tcbalign); 4632 lock_release(rtld_bind_lock, &lockstate); 4633 } 4634 4635 static void 4636 object_add_name(Obj_Entry *obj, const char *name) 4637 { 4638 Name_Entry *entry; 4639 size_t len; 4640 4641 len = strlen(name); 4642 entry = malloc(sizeof(Name_Entry) + len); 4643 4644 if (entry != NULL) { 4645 strcpy(entry->name, name); 4646 STAILQ_INSERT_TAIL(&obj->names, entry, link); 4647 } 4648 } 4649 4650 static int 4651 object_match_name(const Obj_Entry *obj, const char *name) 4652 { 4653 Name_Entry *entry; 4654 4655 STAILQ_FOREACH(entry, &obj->names, link) { 4656 if (strcmp(name, entry->name) == 0) 4657 return (1); 4658 } 4659 return (0); 4660 } 4661 4662 static Obj_Entry * 4663 locate_dependency(const Obj_Entry *obj, const char *name) 4664 { 4665 const Objlist_Entry *entry; 4666 const Needed_Entry *needed; 4667 4668 STAILQ_FOREACH(entry, &list_main, link) { 4669 if (object_match_name(entry->obj, name)) 4670 return entry->obj; 4671 } 4672 4673 for (needed = obj->needed; needed != NULL; needed = needed->next) { 4674 if (strcmp(obj->strtab + needed->name, name) == 0 || 4675 (needed->obj != NULL && object_match_name(needed->obj, name))) { 4676 /* 4677 * If there is DT_NEEDED for the name we are looking for, 4678 * we are all set. Note that object might not be found if 4679 * dependency was not loaded yet, so the function can 4680 * return NULL here. This is expected and handled 4681 * properly by the caller. 4682 */ 4683 return (needed->obj); 4684 } 4685 } 4686 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 4687 obj->path, name); 4688 die(); 4689 } 4690 4691 static int 4692 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 4693 const Elf_Vernaux *vna) 4694 { 4695 const Elf_Verdef *vd; 4696 const char *vername; 4697 4698 vername = refobj->strtab + vna->vna_name; 4699 vd = depobj->verdef; 4700 if (vd == NULL) { 4701 _rtld_error("%s: version %s required by %s not defined", 4702 depobj->path, vername, refobj->path); 4703 return (-1); 4704 } 4705 for (;;) { 4706 if (vd->vd_version != VER_DEF_CURRENT) { 4707 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4708 depobj->path, vd->vd_version); 4709 return (-1); 4710 } 4711 if (vna->vna_hash == vd->vd_hash) { 4712 const Elf_Verdaux *aux = (const Elf_Verdaux *) 4713 ((char *)vd + vd->vd_aux); 4714 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 4715 return (0); 4716 } 4717 if (vd->vd_next == 0) 4718 break; 4719 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4720 } 4721 if (vna->vna_flags & VER_FLG_WEAK) 4722 return (0); 4723 _rtld_error("%s: version %s required by %s not found", 4724 depobj->path, vername, refobj->path); 4725 return (-1); 4726 } 4727 4728 static int 4729 rtld_verify_object_versions(Obj_Entry *obj) 4730 { 4731 const Elf_Verneed *vn; 4732 const Elf_Verdef *vd; 4733 const Elf_Verdaux *vda; 4734 const Elf_Vernaux *vna; 4735 const Obj_Entry *depobj; 4736 int maxvernum, vernum; 4737 4738 if (obj->ver_checked) 4739 return (0); 4740 obj->ver_checked = true; 4741 4742 maxvernum = 0; 4743 /* 4744 * Walk over defined and required version records and figure out 4745 * max index used by any of them. Do very basic sanity checking 4746 * while there. 4747 */ 4748 vn = obj->verneed; 4749 while (vn != NULL) { 4750 if (vn->vn_version != VER_NEED_CURRENT) { 4751 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 4752 obj->path, vn->vn_version); 4753 return (-1); 4754 } 4755 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4756 for (;;) { 4757 vernum = VER_NEED_IDX(vna->vna_other); 4758 if (vernum > maxvernum) 4759 maxvernum = vernum; 4760 if (vna->vna_next == 0) 4761 break; 4762 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4763 } 4764 if (vn->vn_next == 0) 4765 break; 4766 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4767 } 4768 4769 vd = obj->verdef; 4770 while (vd != NULL) { 4771 if (vd->vd_version != VER_DEF_CURRENT) { 4772 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4773 obj->path, vd->vd_version); 4774 return (-1); 4775 } 4776 vernum = VER_DEF_IDX(vd->vd_ndx); 4777 if (vernum > maxvernum) 4778 maxvernum = vernum; 4779 if (vd->vd_next == 0) 4780 break; 4781 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4782 } 4783 4784 if (maxvernum == 0) 4785 return (0); 4786 4787 /* 4788 * Store version information in array indexable by version index. 4789 * Verify that object version requirements are satisfied along the 4790 * way. 4791 */ 4792 obj->vernum = maxvernum + 1; 4793 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 4794 4795 vd = obj->verdef; 4796 while (vd != NULL) { 4797 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 4798 vernum = VER_DEF_IDX(vd->vd_ndx); 4799 assert(vernum <= maxvernum); 4800 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 4801 obj->vertab[vernum].hash = vd->vd_hash; 4802 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 4803 obj->vertab[vernum].file = NULL; 4804 obj->vertab[vernum].flags = 0; 4805 } 4806 if (vd->vd_next == 0) 4807 break; 4808 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4809 } 4810 4811 vn = obj->verneed; 4812 while (vn != NULL) { 4813 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 4814 if (depobj == NULL) 4815 return (-1); 4816 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4817 for (;;) { 4818 if (check_object_provided_version(obj, depobj, vna)) 4819 return (-1); 4820 vernum = VER_NEED_IDX(vna->vna_other); 4821 assert(vernum <= maxvernum); 4822 obj->vertab[vernum].hash = vna->vna_hash; 4823 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 4824 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 4825 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 4826 VER_INFO_HIDDEN : 0; 4827 if (vna->vna_next == 0) 4828 break; 4829 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4830 } 4831 if (vn->vn_next == 0) 4832 break; 4833 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4834 } 4835 return 0; 4836 } 4837 4838 static int 4839 rtld_verify_versions(const Objlist *objlist) 4840 { 4841 Objlist_Entry *entry; 4842 int rc; 4843 4844 rc = 0; 4845 STAILQ_FOREACH(entry, objlist, link) { 4846 /* 4847 * Skip dummy objects or objects that have their version requirements 4848 * already checked. 4849 */ 4850 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 4851 continue; 4852 if (rtld_verify_object_versions(entry->obj) == -1) { 4853 rc = -1; 4854 if (ld_tracing == NULL) 4855 break; 4856 } 4857 } 4858 if (rc == 0 || ld_tracing != NULL) 4859 rc = rtld_verify_object_versions(&obj_rtld); 4860 return rc; 4861 } 4862 4863 const Ver_Entry * 4864 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 4865 { 4866 Elf_Versym vernum; 4867 4868 if (obj->vertab) { 4869 vernum = VER_NDX(obj->versyms[symnum]); 4870 if (vernum >= obj->vernum) { 4871 _rtld_error("%s: symbol %s has wrong verneed value %d", 4872 obj->path, obj->strtab + symnum, vernum); 4873 } else if (obj->vertab[vernum].hash != 0) { 4874 return &obj->vertab[vernum]; 4875 } 4876 } 4877 return NULL; 4878 } 4879 4880 int 4881 _rtld_get_stack_prot(void) 4882 { 4883 4884 return (stack_prot); 4885 } 4886 4887 static void 4888 map_stacks_exec(RtldLockState *lockstate) 4889 { 4890 void (*thr_map_stacks_exec)(void); 4891 4892 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 4893 return; 4894 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 4895 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 4896 if (thr_map_stacks_exec != NULL) { 4897 stack_prot |= PROT_EXEC; 4898 thr_map_stacks_exec(); 4899 } 4900 } 4901 4902 void 4903 symlook_init(SymLook *dst, const char *name) 4904 { 4905 4906 bzero(dst, sizeof(*dst)); 4907 dst->name = name; 4908 dst->hash = elf_hash(name); 4909 dst->hash_gnu = gnu_hash(name); 4910 } 4911 4912 static void 4913 symlook_init_from_req(SymLook *dst, const SymLook *src) 4914 { 4915 4916 dst->name = src->name; 4917 dst->hash = src->hash; 4918 dst->hash_gnu = src->hash_gnu; 4919 dst->ventry = src->ventry; 4920 dst->flags = src->flags; 4921 dst->defobj_out = NULL; 4922 dst->sym_out = NULL; 4923 dst->lockstate = src->lockstate; 4924 } 4925 4926 4927 /* 4928 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 4929 */ 4930 static int 4931 parse_libdir(const char *str) 4932 { 4933 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 4934 const char *orig; 4935 int fd; 4936 char c; 4937 4938 orig = str; 4939 fd = 0; 4940 for (c = *str; c != '\0'; c = *++str) { 4941 if (c < '0' || c > '9') 4942 return (-1); 4943 4944 fd *= RADIX; 4945 fd += c - '0'; 4946 } 4947 4948 /* Make sure we actually parsed something. */ 4949 if (str == orig) { 4950 _rtld_error("failed to parse directory FD from '%s'", str); 4951 return (-1); 4952 } 4953 return (fd); 4954 } 4955 4956 /* 4957 * Overrides for libc_pic-provided functions. 4958 */ 4959 4960 int 4961 __getosreldate(void) 4962 { 4963 size_t len; 4964 int oid[2]; 4965 int error, osrel; 4966 4967 if (osreldate != 0) 4968 return (osreldate); 4969 4970 oid[0] = CTL_KERN; 4971 oid[1] = KERN_OSRELDATE; 4972 osrel = 0; 4973 len = sizeof(osrel); 4974 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 4975 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 4976 osreldate = osrel; 4977 return (osreldate); 4978 } 4979 4980 void 4981 exit(int status) 4982 { 4983 4984 _exit(status); 4985 } 4986 4987 void (*__cleanup)(void); 4988 int __isthreaded = 0; 4989 int _thread_autoinit_dummy_decl = 1; 4990 4991 /* 4992 * No unresolved symbols for rtld. 4993 */ 4994 void 4995 __pthread_cxa_finalize(struct dl_phdr_info *a) 4996 { 4997 } 4998 4999 void 5000 __stack_chk_fail(void) 5001 { 5002 5003 _rtld_error("stack overflow detected; terminated"); 5004 die(); 5005 } 5006 __weak_reference(__stack_chk_fail, __stack_chk_fail_local); 5007 5008 void 5009 __chk_fail(void) 5010 { 5011 5012 _rtld_error("buffer overflow detected; terminated"); 5013 die(); 5014 } 5015 5016 const char * 5017 rtld_strerror(int errnum) 5018 { 5019 5020 if (errnum < 0 || errnum >= sys_nerr) 5021 return ("Unknown error"); 5022 return (sys_errlist[errnum]); 5023 } 5024