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 int __sys_openat(int, const char *, int, ...); 170 171 /* 172 * Data declarations. 173 */ 174 static char *error_message; /* Message for dlerror(), or NULL */ 175 struct r_debug r_debug; /* for GDB; */ 176 static bool libmap_disable; /* Disable libmap */ 177 static bool ld_loadfltr; /* Immediate filters processing */ 178 static char *libmap_override; /* Maps to use in addition to libmap.conf */ 179 static bool trust; /* False for setuid and setgid programs */ 180 static bool dangerous_ld_env; /* True if environment variables have been 181 used to affect the libraries loaded */ 182 static char *ld_bind_now; /* Environment variable for immediate binding */ 183 static char *ld_debug; /* Environment variable for debugging */ 184 static char *ld_library_path; /* Environment variable for search path */ 185 static char *ld_library_dirs; /* Environment variable for library descriptors */ 186 static char *ld_preload; /* Environment variable for libraries to 187 load first */ 188 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 189 static char *ld_tracing; /* Called from ldd to print libs */ 190 static char *ld_utrace; /* Use utrace() to log events. */ 191 static Obj_Entry *obj_list; /* Head of linked list of shared objects */ 192 static Obj_Entry **obj_tail; /* Link field of last object in list */ 193 static Obj_Entry *obj_main; /* The main program shared object */ 194 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 195 static unsigned int obj_count; /* Number of objects in obj_list */ 196 static unsigned int obj_loads; /* Number of objects in obj_list */ 197 198 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 199 STAILQ_HEAD_INITIALIZER(list_global); 200 static Objlist list_main = /* Objects loaded at program startup */ 201 STAILQ_HEAD_INITIALIZER(list_main); 202 static Objlist list_fini = /* Objects needing fini() calls */ 203 STAILQ_HEAD_INITIALIZER(list_fini); 204 205 Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 206 207 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 208 209 extern Elf_Dyn _DYNAMIC; 210 #pragma weak _DYNAMIC 211 #ifndef RTLD_IS_DYNAMIC 212 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL) 213 #endif 214 215 int npagesizes, osreldate; 216 size_t *pagesizes; 217 218 long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0}; 219 220 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 221 static int max_stack_flags; 222 223 /* 224 * Global declarations normally provided by crt1. The dynamic linker is 225 * not built with crt1, so we have to provide them ourselves. 226 */ 227 char *__progname; 228 char **environ; 229 230 /* 231 * Used to pass argc, argv to init functions. 232 */ 233 int main_argc; 234 char **main_argv; 235 236 /* 237 * Globals to control TLS allocation. 238 */ 239 size_t tls_last_offset; /* Static TLS offset of last module */ 240 size_t tls_last_size; /* Static TLS size of last module */ 241 size_t tls_static_space; /* Static TLS space allocated */ 242 size_t tls_static_max_align; 243 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 244 int tls_max_index = 1; /* Largest module index allocated */ 245 246 bool ld_library_path_rpath = false; 247 248 /* 249 * Fill in a DoneList with an allocation large enough to hold all of 250 * the currently-loaded objects. Keep this as a macro since it calls 251 * alloca and we want that to occur within the scope of the caller. 252 */ 253 #define donelist_init(dlp) \ 254 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 255 assert((dlp)->objs != NULL), \ 256 (dlp)->num_alloc = obj_count, \ 257 (dlp)->num_used = 0) 258 259 #define UTRACE_DLOPEN_START 1 260 #define UTRACE_DLOPEN_STOP 2 261 #define UTRACE_DLCLOSE_START 3 262 #define UTRACE_DLCLOSE_STOP 4 263 #define UTRACE_LOAD_OBJECT 5 264 #define UTRACE_UNLOAD_OBJECT 6 265 #define UTRACE_ADD_RUNDEP 7 266 #define UTRACE_PRELOAD_FINISHED 8 267 #define UTRACE_INIT_CALL 9 268 #define UTRACE_FINI_CALL 10 269 #define UTRACE_DLSYM_START 11 270 #define UTRACE_DLSYM_STOP 12 271 272 struct utrace_rtld { 273 char sig[4]; /* 'RTLD' */ 274 int event; 275 void *handle; 276 void *mapbase; /* Used for 'parent' and 'init/fini' */ 277 size_t mapsize; 278 int refcnt; /* Used for 'mode' */ 279 char name[MAXPATHLEN]; 280 }; 281 282 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 283 if (ld_utrace != NULL) \ 284 ld_utrace_log(e, h, mb, ms, r, n); \ 285 } while (0) 286 287 static void 288 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 289 int refcnt, const char *name) 290 { 291 struct utrace_rtld ut; 292 293 ut.sig[0] = 'R'; 294 ut.sig[1] = 'T'; 295 ut.sig[2] = 'L'; 296 ut.sig[3] = 'D'; 297 ut.event = event; 298 ut.handle = handle; 299 ut.mapbase = mapbase; 300 ut.mapsize = mapsize; 301 ut.refcnt = refcnt; 302 bzero(ut.name, sizeof(ut.name)); 303 if (name) 304 strlcpy(ut.name, name, sizeof(ut.name)); 305 utrace(&ut, sizeof(ut)); 306 } 307 308 /* 309 * Main entry point for dynamic linking. The first argument is the 310 * stack pointer. The stack is expected to be laid out as described 311 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 312 * Specifically, the stack pointer points to a word containing 313 * ARGC. Following that in the stack is a null-terminated sequence 314 * of pointers to argument strings. Then comes a null-terminated 315 * sequence of pointers to environment strings. Finally, there is a 316 * sequence of "auxiliary vector" entries. 317 * 318 * The second argument points to a place to store the dynamic linker's 319 * exit procedure pointer and the third to a place to store the main 320 * program's object. 321 * 322 * The return value is the main program's entry point. 323 */ 324 func_ptr_type 325 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 326 { 327 Elf_Auxinfo *aux_info[AT_COUNT]; 328 int i; 329 int argc; 330 char **argv; 331 char **env; 332 Elf_Auxinfo *aux; 333 Elf_Auxinfo *auxp; 334 const char *argv0; 335 Objlist_Entry *entry; 336 Obj_Entry *obj; 337 Obj_Entry **preload_tail; 338 Obj_Entry *last_interposer; 339 Objlist initlist; 340 RtldLockState lockstate; 341 char *library_path_rpath; 342 int mib[2]; 343 size_t len; 344 345 /* 346 * On entry, the dynamic linker itself has not been relocated yet. 347 * Be very careful not to reference any global data until after 348 * init_rtld has returned. It is OK to reference file-scope statics 349 * and string constants, and to call static and global functions. 350 */ 351 352 /* Find the auxiliary vector on the stack. */ 353 argc = *sp++; 354 argv = (char **) sp; 355 sp += argc + 1; /* Skip over arguments and NULL terminator */ 356 env = (char **) sp; 357 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 358 ; 359 aux = (Elf_Auxinfo *) sp; 360 361 /* Digest the auxiliary vector. */ 362 for (i = 0; i < AT_COUNT; i++) 363 aux_info[i] = NULL; 364 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 365 if (auxp->a_type < AT_COUNT) 366 aux_info[auxp->a_type] = auxp; 367 } 368 369 /* Initialize and relocate ourselves. */ 370 assert(aux_info[AT_BASE] != NULL); 371 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 372 373 __progname = obj_rtld.path; 374 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 375 environ = env; 376 main_argc = argc; 377 main_argv = argv; 378 379 if (aux_info[AT_CANARY] != NULL && 380 aux_info[AT_CANARY]->a_un.a_ptr != NULL) { 381 i = aux_info[AT_CANARYLEN]->a_un.a_val; 382 if (i > sizeof(__stack_chk_guard)) 383 i = sizeof(__stack_chk_guard); 384 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i); 385 } else { 386 mib[0] = CTL_KERN; 387 mib[1] = KERN_ARND; 388 389 len = sizeof(__stack_chk_guard); 390 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 || 391 len != sizeof(__stack_chk_guard)) { 392 /* If sysctl was unsuccessful, use the "terminator canary". */ 393 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0; 394 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0; 395 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n'; 396 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255; 397 } 398 } 399 400 trust = !issetugid(); 401 402 ld_bind_now = getenv(LD_ "BIND_NOW"); 403 /* 404 * If the process is tainted, then we un-set the dangerous environment 405 * variables. The process will be marked as tainted until setuid(2) 406 * is called. If any child process calls setuid(2) we do not want any 407 * future processes to honor the potentially un-safe variables. 408 */ 409 if (!trust) { 410 if (unsetenv(LD_ "PRELOAD") || unsetenv(LD_ "LIBMAP") || 411 unsetenv(LD_ "LIBRARY_PATH") || unsetenv(LD_ "LIBRARY_PATH_FDS") || 412 unsetenv(LD_ "LIBMAP_DISABLE") || 413 unsetenv(LD_ "DEBUG") || unsetenv(LD_ "ELF_HINTS_PATH") || 414 unsetenv(LD_ "LOADFLTR") || unsetenv(LD_ "LIBRARY_PATH_RPATH")) { 415 _rtld_error("environment corrupt; aborting"); 416 die(); 417 } 418 } 419 ld_debug = getenv(LD_ "DEBUG"); 420 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL; 421 libmap_override = getenv(LD_ "LIBMAP"); 422 ld_library_path = getenv(LD_ "LIBRARY_PATH"); 423 ld_library_dirs = getenv(LD_ "LIBRARY_PATH_FDS"); 424 ld_preload = getenv(LD_ "PRELOAD"); 425 ld_elf_hints_path = getenv(LD_ "ELF_HINTS_PATH"); 426 ld_loadfltr = getenv(LD_ "LOADFLTR") != NULL; 427 library_path_rpath = getenv(LD_ "LIBRARY_PATH_RPATH"); 428 if (library_path_rpath != NULL) { 429 if (library_path_rpath[0] == 'y' || 430 library_path_rpath[0] == 'Y' || 431 library_path_rpath[0] == '1') 432 ld_library_path_rpath = true; 433 else 434 ld_library_path_rpath = false; 435 } 436 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 437 (ld_library_path != NULL) || (ld_preload != NULL) || 438 (ld_elf_hints_path != NULL) || ld_loadfltr; 439 ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS"); 440 ld_utrace = getenv(LD_ "UTRACE"); 441 442 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 443 ld_elf_hints_path = _PATH_ELF_HINTS; 444 445 if (ld_debug != NULL && *ld_debug != '\0') 446 debug = 1; 447 dbg("%s is initialized, base address = %p", __progname, 448 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 449 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 450 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 451 452 dbg("initializing thread locks"); 453 lockdflt_init(); 454 455 /* 456 * Load the main program, or process its program header if it is 457 * already loaded. 458 */ 459 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */ 460 int fd = aux_info[AT_EXECFD]->a_un.a_val; 461 dbg("loading main program"); 462 obj_main = map_object(fd, argv0, NULL); 463 close(fd); 464 if (obj_main == NULL) 465 die(); 466 max_stack_flags = obj->stack_flags; 467 } else { /* Main program already loaded. */ 468 const Elf_Phdr *phdr; 469 int phnum; 470 caddr_t entry; 471 472 dbg("processing main program's program header"); 473 assert(aux_info[AT_PHDR] != NULL); 474 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 475 assert(aux_info[AT_PHNUM] != NULL); 476 phnum = aux_info[AT_PHNUM]->a_un.a_val; 477 assert(aux_info[AT_PHENT] != NULL); 478 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 479 assert(aux_info[AT_ENTRY] != NULL); 480 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 481 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL) 482 die(); 483 } 484 485 if (aux_info[AT_EXECPATH] != 0) { 486 char *kexecpath; 487 char buf[MAXPATHLEN]; 488 489 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 490 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 491 if (kexecpath[0] == '/') 492 obj_main->path = kexecpath; 493 else if (getcwd(buf, sizeof(buf)) == NULL || 494 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 495 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 496 obj_main->path = xstrdup(argv0); 497 else 498 obj_main->path = xstrdup(buf); 499 } else { 500 dbg("No AT_EXECPATH"); 501 obj_main->path = xstrdup(argv0); 502 } 503 dbg("obj_main path %s", obj_main->path); 504 obj_main->mainprog = true; 505 506 if (aux_info[AT_STACKPROT] != NULL && 507 aux_info[AT_STACKPROT]->a_un.a_val != 0) 508 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 509 510 #ifndef COMPAT_32BIT 511 /* 512 * Get the actual dynamic linker pathname from the executable if 513 * possible. (It should always be possible.) That ensures that 514 * gdb will find the right dynamic linker even if a non-standard 515 * one is being used. 516 */ 517 if (obj_main->interp != NULL && 518 strcmp(obj_main->interp, obj_rtld.path) != 0) { 519 free(obj_rtld.path); 520 obj_rtld.path = xstrdup(obj_main->interp); 521 __progname = obj_rtld.path; 522 } 523 #endif 524 525 digest_dynamic(obj_main, 0); 526 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 527 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 528 obj_main->dynsymcount); 529 530 linkmap_add(obj_main); 531 linkmap_add(&obj_rtld); 532 533 /* Link the main program into the list of objects. */ 534 *obj_tail = obj_main; 535 obj_tail = &obj_main->next; 536 obj_count++; 537 obj_loads++; 538 539 /* Initialize a fake symbol for resolving undefined weak references. */ 540 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 541 sym_zero.st_shndx = SHN_UNDEF; 542 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 543 544 if (!libmap_disable) 545 libmap_disable = (bool)lm_init(libmap_override); 546 547 dbg("loading LD_PRELOAD libraries"); 548 if (load_preload_objects() == -1) 549 die(); 550 preload_tail = obj_tail; 551 552 dbg("loading needed objects"); 553 if (load_needed_objects(obj_main, 0) == -1) 554 die(); 555 556 /* Make a list of all objects loaded at startup. */ 557 last_interposer = obj_main; 558 for (obj = obj_list; obj != NULL; obj = obj->next) { 559 if (obj->z_interpose && obj != obj_main) { 560 objlist_put_after(&list_main, last_interposer, obj); 561 last_interposer = obj; 562 } else { 563 objlist_push_tail(&list_main, obj); 564 } 565 obj->refcount++; 566 } 567 568 dbg("checking for required versions"); 569 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 570 die(); 571 572 if (ld_tracing) { /* We're done */ 573 trace_loaded_objects(obj_main); 574 exit(0); 575 } 576 577 if (getenv(LD_ "DUMP_REL_PRE") != NULL) { 578 dump_relocations(obj_main); 579 exit (0); 580 } 581 582 /* 583 * Processing tls relocations requires having the tls offsets 584 * initialized. Prepare offsets before starting initial 585 * relocation processing. 586 */ 587 dbg("initializing initial thread local storage offsets"); 588 STAILQ_FOREACH(entry, &list_main, link) { 589 /* 590 * Allocate all the initial objects out of the static TLS 591 * block even if they didn't ask for it. 592 */ 593 allocate_tls_offset(entry->obj); 594 } 595 596 if (relocate_objects(obj_main, 597 ld_bind_now != NULL && *ld_bind_now != '\0', 598 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 599 die(); 600 601 dbg("doing copy relocations"); 602 if (do_copy_relocations(obj_main) == -1) 603 die(); 604 605 if (getenv(LD_ "DUMP_REL_POST") != NULL) { 606 dump_relocations(obj_main); 607 exit (0); 608 } 609 610 /* 611 * Setup TLS for main thread. This must be done after the 612 * relocations are processed, since tls initialization section 613 * might be the subject for relocations. 614 */ 615 dbg("initializing initial thread local storage"); 616 allocate_initial_tls(obj_list); 617 618 dbg("initializing key program variables"); 619 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 620 set_program_var("environ", env); 621 set_program_var("__elf_aux_vector", aux); 622 623 /* Make a list of init functions to call. */ 624 objlist_init(&initlist); 625 initlist_add_objects(obj_list, preload_tail, &initlist); 626 627 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 628 629 map_stacks_exec(NULL); 630 631 dbg("resolving ifuncs"); 632 if (resolve_objects_ifunc(obj_main, 633 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY, 634 NULL) == -1) 635 die(); 636 637 if (!obj_main->crt_no_init) { 638 /* 639 * Make sure we don't call the main program's init and fini 640 * functions for binaries linked with old crt1 which calls 641 * _init itself. 642 */ 643 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 644 obj_main->preinit_array = obj_main->init_array = 645 obj_main->fini_array = (Elf_Addr)NULL; 646 } 647 648 wlock_acquire(rtld_bind_lock, &lockstate); 649 if (obj_main->crt_no_init) 650 preinit_main(); 651 objlist_call_init(&initlist, &lockstate); 652 _r_debug_postinit(&obj_main->linkmap); 653 objlist_clear(&initlist); 654 dbg("loading filtees"); 655 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 656 if (ld_loadfltr || obj->z_loadfltr) 657 load_filtees(obj, 0, &lockstate); 658 } 659 lock_release(rtld_bind_lock, &lockstate); 660 661 dbg("transferring control to program entry point = %p", obj_main->entry); 662 663 /* Return the exit procedure and the program entry point. */ 664 *exit_proc = rtld_exit; 665 *objp = obj_main; 666 return (func_ptr_type) obj_main->entry; 667 } 668 669 void * 670 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 671 { 672 void *ptr; 673 Elf_Addr target; 674 675 ptr = (void *)make_function_pointer(def, obj); 676 target = ((Elf_Addr (*)(void))ptr)(); 677 return ((void *)target); 678 } 679 680 Elf_Addr 681 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 682 { 683 const Elf_Rel *rel; 684 const Elf_Sym *def; 685 const Obj_Entry *defobj; 686 Elf_Addr *where; 687 Elf_Addr target; 688 RtldLockState lockstate; 689 690 rlock_acquire(rtld_bind_lock, &lockstate); 691 if (sigsetjmp(lockstate.env, 0) != 0) 692 lock_upgrade(rtld_bind_lock, &lockstate); 693 if (obj->pltrel) 694 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 695 else 696 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 697 698 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 699 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL, 700 &lockstate); 701 if (def == NULL) 702 die(); 703 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 704 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 705 else 706 target = (Elf_Addr)(defobj->relocbase + def->st_value); 707 708 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 709 defobj->strtab + def->st_name, basename(obj->path), 710 (void *)target, basename(defobj->path)); 711 712 /* 713 * Write the new contents for the jmpslot. Note that depending on 714 * architecture, the value which we need to return back to the 715 * lazy binding trampoline may or may not be the target 716 * address. The value returned from reloc_jmpslot() is the value 717 * that the trampoline needs. 718 */ 719 target = reloc_jmpslot(where, target, defobj, obj, rel); 720 lock_release(rtld_bind_lock, &lockstate); 721 return target; 722 } 723 724 /* 725 * Error reporting function. Use it like printf. If formats the message 726 * into a buffer, and sets things up so that the next call to dlerror() 727 * will return the message. 728 */ 729 void 730 _rtld_error(const char *fmt, ...) 731 { 732 static char buf[512]; 733 va_list ap; 734 735 va_start(ap, fmt); 736 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 737 error_message = buf; 738 va_end(ap); 739 } 740 741 /* 742 * Return a dynamically-allocated copy of the current error message, if any. 743 */ 744 static char * 745 errmsg_save(void) 746 { 747 return error_message == NULL ? NULL : xstrdup(error_message); 748 } 749 750 /* 751 * Restore the current error message from a copy which was previously saved 752 * by errmsg_save(). The copy is freed. 753 */ 754 static void 755 errmsg_restore(char *saved_msg) 756 { 757 if (saved_msg == NULL) 758 error_message = NULL; 759 else { 760 _rtld_error("%s", saved_msg); 761 free(saved_msg); 762 } 763 } 764 765 static const char * 766 basename(const char *name) 767 { 768 const char *p = strrchr(name, '/'); 769 return p != NULL ? p + 1 : name; 770 } 771 772 static struct utsname uts; 773 774 static char * 775 origin_subst_one(char *real, const char *kw, const char *subst, 776 bool may_free) 777 { 778 char *p, *p1, *res, *resp; 779 int subst_len, kw_len, subst_count, old_len, new_len; 780 781 kw_len = strlen(kw); 782 783 /* 784 * First, count the number of the keyword occurences, to 785 * preallocate the final string. 786 */ 787 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 788 p1 = strstr(p, kw); 789 if (p1 == NULL) 790 break; 791 } 792 793 /* 794 * If the keyword is not found, just return. 795 */ 796 if (subst_count == 0) 797 return (may_free ? real : xstrdup(real)); 798 799 /* 800 * There is indeed something to substitute. Calculate the 801 * length of the resulting string, and allocate it. 802 */ 803 subst_len = strlen(subst); 804 old_len = strlen(real); 805 new_len = old_len + (subst_len - kw_len) * subst_count; 806 res = xmalloc(new_len + 1); 807 808 /* 809 * Now, execute the substitution loop. 810 */ 811 for (p = real, resp = res, *resp = '\0';;) { 812 p1 = strstr(p, kw); 813 if (p1 != NULL) { 814 /* Copy the prefix before keyword. */ 815 memcpy(resp, p, p1 - p); 816 resp += p1 - p; 817 /* Keyword replacement. */ 818 memcpy(resp, subst, subst_len); 819 resp += subst_len; 820 *resp = '\0'; 821 p = p1 + kw_len; 822 } else 823 break; 824 } 825 826 /* Copy to the end of string and finish. */ 827 strcat(resp, p); 828 if (may_free) 829 free(real); 830 return (res); 831 } 832 833 static char * 834 origin_subst(char *real, const char *origin_path) 835 { 836 char *res1, *res2, *res3, *res4; 837 838 if (uts.sysname[0] == '\0') { 839 if (uname(&uts) != 0) { 840 _rtld_error("utsname failed: %d", errno); 841 return (NULL); 842 } 843 } 844 res1 = origin_subst_one(real, "$ORIGIN", origin_path, false); 845 res2 = origin_subst_one(res1, "$OSNAME", uts.sysname, true); 846 res3 = origin_subst_one(res2, "$OSREL", uts.release, true); 847 res4 = origin_subst_one(res3, "$PLATFORM", uts.machine, true); 848 return (res4); 849 } 850 851 static void 852 die(void) 853 { 854 const char *msg = dlerror(); 855 856 if (msg == NULL) 857 msg = "Fatal error"; 858 rtld_fdputstr(STDERR_FILENO, msg); 859 rtld_fdputchar(STDERR_FILENO, '\n'); 860 _exit(1); 861 } 862 863 /* 864 * Process a shared object's DYNAMIC section, and save the important 865 * information in its Obj_Entry structure. 866 */ 867 static void 868 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 869 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 870 { 871 const Elf_Dyn *dynp; 872 Needed_Entry **needed_tail = &obj->needed; 873 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 874 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 875 const Elf_Hashelt *hashtab; 876 const Elf32_Word *hashval; 877 Elf32_Word bkt, nmaskwords; 878 int bloom_size32; 879 bool nmw_power2; 880 int plttype = DT_REL; 881 882 *dyn_rpath = NULL; 883 *dyn_soname = NULL; 884 *dyn_runpath = NULL; 885 886 obj->bind_now = false; 887 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 888 switch (dynp->d_tag) { 889 890 case DT_REL: 891 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 892 break; 893 894 case DT_RELSZ: 895 obj->relsize = dynp->d_un.d_val; 896 break; 897 898 case DT_RELENT: 899 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 900 break; 901 902 case DT_JMPREL: 903 obj->pltrel = (const Elf_Rel *) 904 (obj->relocbase + dynp->d_un.d_ptr); 905 break; 906 907 case DT_PLTRELSZ: 908 obj->pltrelsize = dynp->d_un.d_val; 909 break; 910 911 case DT_RELA: 912 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 913 break; 914 915 case DT_RELASZ: 916 obj->relasize = dynp->d_un.d_val; 917 break; 918 919 case DT_RELAENT: 920 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 921 break; 922 923 case DT_PLTREL: 924 plttype = dynp->d_un.d_val; 925 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 926 break; 927 928 case DT_SYMTAB: 929 obj->symtab = (const Elf_Sym *) 930 (obj->relocbase + dynp->d_un.d_ptr); 931 break; 932 933 case DT_SYMENT: 934 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 935 break; 936 937 case DT_STRTAB: 938 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 939 break; 940 941 case DT_STRSZ: 942 obj->strsize = dynp->d_un.d_val; 943 break; 944 945 case DT_VERNEED: 946 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 947 dynp->d_un.d_val); 948 break; 949 950 case DT_VERNEEDNUM: 951 obj->verneednum = dynp->d_un.d_val; 952 break; 953 954 case DT_VERDEF: 955 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 956 dynp->d_un.d_val); 957 break; 958 959 case DT_VERDEFNUM: 960 obj->verdefnum = dynp->d_un.d_val; 961 break; 962 963 case DT_VERSYM: 964 obj->versyms = (const Elf_Versym *)(obj->relocbase + 965 dynp->d_un.d_val); 966 break; 967 968 case DT_HASH: 969 { 970 hashtab = (const Elf_Hashelt *)(obj->relocbase + 971 dynp->d_un.d_ptr); 972 obj->nbuckets = hashtab[0]; 973 obj->nchains = hashtab[1]; 974 obj->buckets = hashtab + 2; 975 obj->chains = obj->buckets + obj->nbuckets; 976 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 977 obj->buckets != NULL; 978 } 979 break; 980 981 case DT_GNU_HASH: 982 { 983 hashtab = (const Elf_Hashelt *)(obj->relocbase + 984 dynp->d_un.d_ptr); 985 obj->nbuckets_gnu = hashtab[0]; 986 obj->symndx_gnu = hashtab[1]; 987 nmaskwords = hashtab[2]; 988 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 989 /* Number of bitmask words is required to be power of 2 */ 990 nmw_power2 = ((nmaskwords & (nmaskwords - 1)) == 0); 991 obj->maskwords_bm_gnu = nmaskwords - 1; 992 obj->shift2_gnu = hashtab[3]; 993 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4); 994 obj->buckets_gnu = hashtab + 4 + bloom_size32; 995 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 996 obj->symndx_gnu; 997 obj->valid_hash_gnu = nmw_power2 && obj->nbuckets_gnu > 0 && 998 obj->buckets_gnu != NULL; 999 } 1000 break; 1001 1002 case DT_NEEDED: 1003 if (!obj->rtld) { 1004 Needed_Entry *nep = NEW(Needed_Entry); 1005 nep->name = dynp->d_un.d_val; 1006 nep->obj = NULL; 1007 nep->next = NULL; 1008 1009 *needed_tail = nep; 1010 needed_tail = &nep->next; 1011 } 1012 break; 1013 1014 case DT_FILTER: 1015 if (!obj->rtld) { 1016 Needed_Entry *nep = NEW(Needed_Entry); 1017 nep->name = dynp->d_un.d_val; 1018 nep->obj = NULL; 1019 nep->next = NULL; 1020 1021 *needed_filtees_tail = nep; 1022 needed_filtees_tail = &nep->next; 1023 } 1024 break; 1025 1026 case DT_AUXILIARY: 1027 if (!obj->rtld) { 1028 Needed_Entry *nep = NEW(Needed_Entry); 1029 nep->name = dynp->d_un.d_val; 1030 nep->obj = NULL; 1031 nep->next = NULL; 1032 1033 *needed_aux_filtees_tail = nep; 1034 needed_aux_filtees_tail = &nep->next; 1035 } 1036 break; 1037 1038 case DT_PLTGOT: 1039 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 1040 break; 1041 1042 case DT_TEXTREL: 1043 obj->textrel = true; 1044 break; 1045 1046 case DT_SYMBOLIC: 1047 obj->symbolic = true; 1048 break; 1049 1050 case DT_RPATH: 1051 /* 1052 * We have to wait until later to process this, because we 1053 * might not have gotten the address of the string table yet. 1054 */ 1055 *dyn_rpath = dynp; 1056 break; 1057 1058 case DT_SONAME: 1059 *dyn_soname = dynp; 1060 break; 1061 1062 case DT_RUNPATH: 1063 *dyn_runpath = dynp; 1064 break; 1065 1066 case DT_INIT: 1067 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1068 break; 1069 1070 case DT_PREINIT_ARRAY: 1071 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1072 break; 1073 1074 case DT_PREINIT_ARRAYSZ: 1075 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1076 break; 1077 1078 case DT_INIT_ARRAY: 1079 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1080 break; 1081 1082 case DT_INIT_ARRAYSZ: 1083 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1084 break; 1085 1086 case DT_FINI: 1087 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1088 break; 1089 1090 case DT_FINI_ARRAY: 1091 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1092 break; 1093 1094 case DT_FINI_ARRAYSZ: 1095 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1096 break; 1097 1098 /* 1099 * Don't process DT_DEBUG on MIPS as the dynamic section 1100 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1101 */ 1102 1103 #ifndef __mips__ 1104 case DT_DEBUG: 1105 /* XXX - not implemented yet */ 1106 if (!early) 1107 dbg("Filling in DT_DEBUG entry"); 1108 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 1109 break; 1110 #endif 1111 1112 case DT_FLAGS: 1113 if ((dynp->d_un.d_val & DF_ORIGIN) && trust) 1114 obj->z_origin = true; 1115 if (dynp->d_un.d_val & DF_SYMBOLIC) 1116 obj->symbolic = true; 1117 if (dynp->d_un.d_val & DF_TEXTREL) 1118 obj->textrel = true; 1119 if (dynp->d_un.d_val & DF_BIND_NOW) 1120 obj->bind_now = true; 1121 /*if (dynp->d_un.d_val & DF_STATIC_TLS) 1122 ;*/ 1123 break; 1124 #ifdef __mips__ 1125 case DT_MIPS_LOCAL_GOTNO: 1126 obj->local_gotno = dynp->d_un.d_val; 1127 break; 1128 1129 case DT_MIPS_SYMTABNO: 1130 obj->symtabno = dynp->d_un.d_val; 1131 break; 1132 1133 case DT_MIPS_GOTSYM: 1134 obj->gotsym = dynp->d_un.d_val; 1135 break; 1136 1137 case DT_MIPS_RLD_MAP: 1138 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1139 break; 1140 #endif 1141 1142 case DT_FLAGS_1: 1143 if (dynp->d_un.d_val & DF_1_NOOPEN) 1144 obj->z_noopen = true; 1145 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust) 1146 obj->z_origin = true; 1147 /*if (dynp->d_un.d_val & DF_1_GLOBAL) 1148 XXX ;*/ 1149 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1150 obj->bind_now = true; 1151 if (dynp->d_un.d_val & DF_1_NODELETE) 1152 obj->z_nodelete = true; 1153 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1154 obj->z_loadfltr = true; 1155 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1156 obj->z_interpose = true; 1157 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1158 obj->z_nodeflib = true; 1159 break; 1160 1161 default: 1162 if (!early) { 1163 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1164 (long)dynp->d_tag); 1165 } 1166 break; 1167 } 1168 } 1169 1170 obj->traced = false; 1171 1172 if (plttype == DT_RELA) { 1173 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1174 obj->pltrel = NULL; 1175 obj->pltrelasize = obj->pltrelsize; 1176 obj->pltrelsize = 0; 1177 } 1178 1179 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1180 if (obj->valid_hash_sysv) 1181 obj->dynsymcount = obj->nchains; 1182 else if (obj->valid_hash_gnu) { 1183 obj->dynsymcount = 0; 1184 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1185 if (obj->buckets_gnu[bkt] == 0) 1186 continue; 1187 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1188 do 1189 obj->dynsymcount++; 1190 while ((*hashval++ & 1u) == 0); 1191 } 1192 obj->dynsymcount += obj->symndx_gnu; 1193 } 1194 } 1195 1196 static void 1197 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1198 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1199 { 1200 1201 if (obj->z_origin && obj->origin_path == NULL) { 1202 obj->origin_path = xmalloc(PATH_MAX); 1203 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1) 1204 die(); 1205 } 1206 1207 if (dyn_runpath != NULL) { 1208 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val; 1209 if (obj->z_origin) 1210 obj->runpath = origin_subst(obj->runpath, obj->origin_path); 1211 } 1212 else if (dyn_rpath != NULL) { 1213 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 1214 if (obj->z_origin) 1215 obj->rpath = origin_subst(obj->rpath, obj->origin_path); 1216 } 1217 1218 if (dyn_soname != NULL) 1219 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1220 } 1221 1222 static void 1223 digest_dynamic(Obj_Entry *obj, int early) 1224 { 1225 const Elf_Dyn *dyn_rpath; 1226 const Elf_Dyn *dyn_soname; 1227 const Elf_Dyn *dyn_runpath; 1228 1229 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1230 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath); 1231 } 1232 1233 /* 1234 * Process a shared object's program header. This is used only for the 1235 * main program, when the kernel has already loaded the main program 1236 * into memory before calling the dynamic linker. It creates and 1237 * returns an Obj_Entry structure. 1238 */ 1239 static Obj_Entry * 1240 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1241 { 1242 Obj_Entry *obj; 1243 const Elf_Phdr *phlimit = phdr + phnum; 1244 const Elf_Phdr *ph; 1245 Elf_Addr note_start, note_end; 1246 int nsegs = 0; 1247 1248 obj = obj_new(); 1249 for (ph = phdr; ph < phlimit; ph++) { 1250 if (ph->p_type != PT_PHDR) 1251 continue; 1252 1253 obj->phdr = phdr; 1254 obj->phsize = ph->p_memsz; 1255 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1256 break; 1257 } 1258 1259 obj->stack_flags = PF_X | PF_R | PF_W; 1260 1261 for (ph = phdr; ph < phlimit; ph++) { 1262 switch (ph->p_type) { 1263 1264 case PT_INTERP: 1265 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1266 break; 1267 1268 case PT_LOAD: 1269 if (nsegs == 0) { /* First load segment */ 1270 obj->vaddrbase = trunc_page(ph->p_vaddr); 1271 obj->mapbase = obj->vaddrbase + obj->relocbase; 1272 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1273 obj->vaddrbase; 1274 } else { /* Last load segment */ 1275 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1276 obj->vaddrbase; 1277 } 1278 nsegs++; 1279 break; 1280 1281 case PT_DYNAMIC: 1282 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1283 break; 1284 1285 case PT_TLS: 1286 obj->tlsindex = 1; 1287 obj->tlssize = ph->p_memsz; 1288 obj->tlsalign = ph->p_align; 1289 obj->tlsinitsize = ph->p_filesz; 1290 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1291 break; 1292 1293 case PT_GNU_STACK: 1294 obj->stack_flags = ph->p_flags; 1295 break; 1296 1297 case PT_GNU_RELRO: 1298 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1299 obj->relro_size = round_page(ph->p_memsz); 1300 break; 1301 1302 case PT_NOTE: 1303 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1304 note_end = note_start + ph->p_filesz; 1305 digest_notes(obj, note_start, note_end); 1306 break; 1307 } 1308 } 1309 if (nsegs < 1) { 1310 _rtld_error("%s: too few PT_LOAD segments", path); 1311 return NULL; 1312 } 1313 1314 obj->entry = entry; 1315 return obj; 1316 } 1317 1318 void 1319 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1320 { 1321 const Elf_Note *note; 1322 const char *note_name; 1323 uintptr_t p; 1324 1325 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1326 note = (const Elf_Note *)((const char *)(note + 1) + 1327 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1328 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1329 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1330 note->n_descsz != sizeof(int32_t)) 1331 continue; 1332 if (note->n_type != ABI_NOTETYPE && 1333 note->n_type != CRT_NOINIT_NOTETYPE) 1334 continue; 1335 note_name = (const char *)(note + 1); 1336 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1337 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1338 continue; 1339 switch (note->n_type) { 1340 case ABI_NOTETYPE: 1341 /* FreeBSD osrel note */ 1342 p = (uintptr_t)(note + 1); 1343 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1344 obj->osrel = *(const int32_t *)(p); 1345 dbg("note osrel %d", obj->osrel); 1346 break; 1347 case CRT_NOINIT_NOTETYPE: 1348 /* FreeBSD 'crt does not call init' note */ 1349 obj->crt_no_init = true; 1350 dbg("note crt_no_init"); 1351 break; 1352 } 1353 } 1354 } 1355 1356 static Obj_Entry * 1357 dlcheck(void *handle) 1358 { 1359 Obj_Entry *obj; 1360 1361 for (obj = obj_list; obj != NULL; obj = obj->next) 1362 if (obj == (Obj_Entry *) handle) 1363 break; 1364 1365 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1366 _rtld_error("Invalid shared object handle %p", handle); 1367 return NULL; 1368 } 1369 return obj; 1370 } 1371 1372 /* 1373 * If the given object is already in the donelist, return true. Otherwise 1374 * add the object to the list and return false. 1375 */ 1376 static bool 1377 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1378 { 1379 unsigned int i; 1380 1381 for (i = 0; i < dlp->num_used; i++) 1382 if (dlp->objs[i] == obj) 1383 return true; 1384 /* 1385 * Our donelist allocation should always be sufficient. But if 1386 * our threads locking isn't working properly, more shared objects 1387 * could have been loaded since we allocated the list. That should 1388 * never happen, but we'll handle it properly just in case it does. 1389 */ 1390 if (dlp->num_used < dlp->num_alloc) 1391 dlp->objs[dlp->num_used++] = obj; 1392 return false; 1393 } 1394 1395 /* 1396 * Hash function for symbol table lookup. Don't even think about changing 1397 * this. It is specified by the System V ABI. 1398 */ 1399 unsigned long 1400 elf_hash(const char *name) 1401 { 1402 const unsigned char *p = (const unsigned char *) name; 1403 unsigned long h = 0; 1404 unsigned long g; 1405 1406 while (*p != '\0') { 1407 h = (h << 4) + *p++; 1408 if ((g = h & 0xf0000000) != 0) 1409 h ^= g >> 24; 1410 h &= ~g; 1411 } 1412 return h; 1413 } 1414 1415 /* 1416 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1417 * unsigned in case it's implemented with a wider type. 1418 */ 1419 static uint32_t 1420 gnu_hash(const char *s) 1421 { 1422 uint32_t h; 1423 unsigned char c; 1424 1425 h = 5381; 1426 for (c = *s; c != '\0'; c = *++s) 1427 h = h * 33 + c; 1428 return (h & 0xffffffff); 1429 } 1430 1431 1432 /* 1433 * Find the library with the given name, and return its full pathname. 1434 * The returned string is dynamically allocated. Generates an error 1435 * message and returns NULL if the library cannot be found. 1436 * 1437 * If the second argument is non-NULL, then it refers to an already- 1438 * loaded shared object, whose library search path will be searched. 1439 * 1440 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1441 * descriptor (which is close-on-exec) will be passed out via the third 1442 * argument. 1443 * 1444 * The search order is: 1445 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1446 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1447 * LD_LIBRARY_PATH 1448 * DT_RUNPATH in the referencing file 1449 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1450 * from list) 1451 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1452 * 1453 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1454 */ 1455 static char * 1456 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1457 { 1458 char *pathname; 1459 char *name; 1460 bool nodeflib, objgiven; 1461 1462 objgiven = refobj != NULL; 1463 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */ 1464 if (xname[0] != '/' && !trust) { 1465 _rtld_error("Absolute pathname required for shared object \"%s\"", 1466 xname); 1467 return NULL; 1468 } 1469 if (objgiven && refobj->z_origin) { 1470 return (origin_subst(__DECONST(char *, xname), 1471 refobj->origin_path)); 1472 } else { 1473 return (xstrdup(xname)); 1474 } 1475 } 1476 1477 if (libmap_disable || !objgiven || 1478 (name = lm_find(refobj->path, xname)) == NULL) 1479 name = (char *)xname; 1480 1481 dbg(" Searching for \"%s\"", name); 1482 1483 /* 1484 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1485 * back to pre-conforming behaviour if user requested so with 1486 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1487 * nodeflib. 1488 */ 1489 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1490 if ((pathname = search_library_path(name, ld_library_path)) != NULL || 1491 (refobj != NULL && 1492 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1493 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL || 1494 (pathname = search_library_path(name, gethints(false))) != NULL || 1495 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL) 1496 return (pathname); 1497 } else { 1498 nodeflib = objgiven ? refobj->z_nodeflib : false; 1499 if ((objgiven && 1500 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1501 (objgiven && refobj->runpath == NULL && refobj != obj_main && 1502 (pathname = search_library_path(name, obj_main->rpath)) != NULL) || 1503 (pathname = search_library_path(name, ld_library_path)) != NULL || 1504 (objgiven && 1505 (pathname = search_library_path(name, refobj->runpath)) != NULL) || 1506 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL || 1507 (pathname = search_library_path(name, gethints(nodeflib))) != NULL || 1508 (objgiven && !nodeflib && 1509 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)) 1510 return (pathname); 1511 } 1512 1513 if (objgiven && refobj->path != NULL) { 1514 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 1515 name, basename(refobj->path)); 1516 } else { 1517 _rtld_error("Shared object \"%s\" not found", name); 1518 } 1519 return NULL; 1520 } 1521 1522 /* 1523 * Given a symbol number in a referencing object, find the corresponding 1524 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1525 * no definition was found. Returns a pointer to the Obj_Entry of the 1526 * defining object via the reference parameter DEFOBJ_OUT. 1527 */ 1528 const Elf_Sym * 1529 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1530 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1531 RtldLockState *lockstate) 1532 { 1533 const Elf_Sym *ref; 1534 const Elf_Sym *def; 1535 const Obj_Entry *defobj; 1536 SymLook req; 1537 const char *name; 1538 int res; 1539 1540 /* 1541 * If we have already found this symbol, get the information from 1542 * the cache. 1543 */ 1544 if (symnum >= refobj->dynsymcount) 1545 return NULL; /* Bad object */ 1546 if (cache != NULL && cache[symnum].sym != NULL) { 1547 *defobj_out = cache[symnum].obj; 1548 return cache[symnum].sym; 1549 } 1550 1551 ref = refobj->symtab + symnum; 1552 name = refobj->strtab + ref->st_name; 1553 def = NULL; 1554 defobj = NULL; 1555 1556 /* 1557 * We don't have to do a full scale lookup if the symbol is local. 1558 * We know it will bind to the instance in this load module; to 1559 * which we already have a pointer (ie ref). By not doing a lookup, 1560 * we not only improve performance, but it also avoids unresolvable 1561 * symbols when local symbols are not in the hash table. This has 1562 * been seen with the ia64 toolchain. 1563 */ 1564 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1565 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1566 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1567 symnum); 1568 } 1569 symlook_init(&req, name); 1570 req.flags = flags; 1571 req.ventry = fetch_ventry(refobj, symnum); 1572 req.lockstate = lockstate; 1573 res = symlook_default(&req, refobj); 1574 if (res == 0) { 1575 def = req.sym_out; 1576 defobj = req.defobj_out; 1577 } 1578 } else { 1579 def = ref; 1580 defobj = refobj; 1581 } 1582 1583 /* 1584 * If we found no definition and the reference is weak, treat the 1585 * symbol as having the value zero. 1586 */ 1587 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1588 def = &sym_zero; 1589 defobj = obj_main; 1590 } 1591 1592 if (def != NULL) { 1593 *defobj_out = defobj; 1594 /* Record the information in the cache to avoid subsequent lookups. */ 1595 if (cache != NULL) { 1596 cache[symnum].sym = def; 1597 cache[symnum].obj = defobj; 1598 } 1599 } else { 1600 if (refobj != &obj_rtld) 1601 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name); 1602 } 1603 return def; 1604 } 1605 1606 /* 1607 * Return the search path from the ldconfig hints file, reading it if 1608 * necessary. If nostdlib is true, then the default search paths are 1609 * not added to result. 1610 * 1611 * Returns NULL if there are problems with the hints file, 1612 * or if the search path there is empty. 1613 */ 1614 static const char * 1615 gethints(bool nostdlib) 1616 { 1617 static char *hints, *filtered_path; 1618 struct elfhints_hdr hdr; 1619 struct fill_search_info_args sargs, hargs; 1620 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1621 struct dl_serpath *SLPpath, *hintpath; 1622 char *p; 1623 unsigned int SLPndx, hintndx, fndx, fcount; 1624 int fd; 1625 size_t flen; 1626 bool skip; 1627 1628 /* First call, read the hints file */ 1629 if (hints == NULL) { 1630 /* Keep from trying again in case the hints file is bad. */ 1631 hints = ""; 1632 1633 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1634 return (NULL); 1635 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1636 hdr.magic != ELFHINTS_MAGIC || 1637 hdr.version != 1) { 1638 close(fd); 1639 return (NULL); 1640 } 1641 p = xmalloc(hdr.dirlistlen + 1); 1642 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1643 read(fd, p, hdr.dirlistlen + 1) != 1644 (ssize_t)hdr.dirlistlen + 1) { 1645 free(p); 1646 close(fd); 1647 return (NULL); 1648 } 1649 hints = p; 1650 close(fd); 1651 } 1652 1653 /* 1654 * If caller agreed to receive list which includes the default 1655 * paths, we are done. Otherwise, if we still did not 1656 * calculated filtered result, do it now. 1657 */ 1658 if (!nostdlib) 1659 return (hints[0] != '\0' ? hints : NULL); 1660 if (filtered_path != NULL) 1661 goto filt_ret; 1662 1663 /* 1664 * Obtain the list of all configured search paths, and the 1665 * list of the default paths. 1666 * 1667 * First estimate the size of the results. 1668 */ 1669 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1670 smeta.dls_cnt = 0; 1671 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1672 hmeta.dls_cnt = 0; 1673 1674 sargs.request = RTLD_DI_SERINFOSIZE; 1675 sargs.serinfo = &smeta; 1676 hargs.request = RTLD_DI_SERINFOSIZE; 1677 hargs.serinfo = &hmeta; 1678 1679 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1680 path_enumerate(p, fill_search_info, &hargs); 1681 1682 SLPinfo = xmalloc(smeta.dls_size); 1683 hintinfo = xmalloc(hmeta.dls_size); 1684 1685 /* 1686 * Next fetch both sets of paths. 1687 */ 1688 sargs.request = RTLD_DI_SERINFO; 1689 sargs.serinfo = SLPinfo; 1690 sargs.serpath = &SLPinfo->dls_serpath[0]; 1691 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1692 1693 hargs.request = RTLD_DI_SERINFO; 1694 hargs.serinfo = hintinfo; 1695 hargs.serpath = &hintinfo->dls_serpath[0]; 1696 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1697 1698 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1699 path_enumerate(p, fill_search_info, &hargs); 1700 1701 /* 1702 * Now calculate the difference between two sets, by excluding 1703 * standard paths from the full set. 1704 */ 1705 fndx = 0; 1706 fcount = 0; 1707 filtered_path = xmalloc(hdr.dirlistlen + 1); 1708 hintpath = &hintinfo->dls_serpath[0]; 1709 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1710 skip = false; 1711 SLPpath = &SLPinfo->dls_serpath[0]; 1712 /* 1713 * Check each standard path against current. 1714 */ 1715 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1716 /* matched, skip the path */ 1717 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1718 skip = true; 1719 break; 1720 } 1721 } 1722 if (skip) 1723 continue; 1724 /* 1725 * Not matched against any standard path, add the path 1726 * to result. Separate consequtive paths with ':'. 1727 */ 1728 if (fcount > 0) { 1729 filtered_path[fndx] = ':'; 1730 fndx++; 1731 } 1732 fcount++; 1733 flen = strlen(hintpath->dls_name); 1734 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1735 fndx += flen; 1736 } 1737 filtered_path[fndx] = '\0'; 1738 1739 free(SLPinfo); 1740 free(hintinfo); 1741 1742 filt_ret: 1743 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1744 } 1745 1746 static void 1747 init_dag(Obj_Entry *root) 1748 { 1749 const Needed_Entry *needed; 1750 const Objlist_Entry *elm; 1751 DoneList donelist; 1752 1753 if (root->dag_inited) 1754 return; 1755 donelist_init(&donelist); 1756 1757 /* Root object belongs to own DAG. */ 1758 objlist_push_tail(&root->dldags, root); 1759 objlist_push_tail(&root->dagmembers, root); 1760 donelist_check(&donelist, root); 1761 1762 /* 1763 * Add dependencies of root object to DAG in breadth order 1764 * by exploiting the fact that each new object get added 1765 * to the tail of the dagmembers list. 1766 */ 1767 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1768 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1769 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1770 continue; 1771 objlist_push_tail(&needed->obj->dldags, root); 1772 objlist_push_tail(&root->dagmembers, needed->obj); 1773 } 1774 } 1775 root->dag_inited = true; 1776 } 1777 1778 static void 1779 process_nodelete(Obj_Entry *root) 1780 { 1781 const Objlist_Entry *elm; 1782 1783 /* 1784 * Walk over object DAG and process every dependent object that 1785 * is marked as DF_1_NODELETE. They need to grow their own DAG, 1786 * which then should have its reference upped separately. 1787 */ 1788 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1789 if (elm->obj != NULL && elm->obj->z_nodelete && 1790 !elm->obj->ref_nodel) { 1791 dbg("obj %s nodelete", elm->obj->path); 1792 init_dag(elm->obj); 1793 ref_dag(elm->obj); 1794 elm->obj->ref_nodel = true; 1795 } 1796 } 1797 } 1798 /* 1799 * Initialize the dynamic linker. The argument is the address at which 1800 * the dynamic linker has been mapped into memory. The primary task of 1801 * this function is to relocate the dynamic linker. 1802 */ 1803 static void 1804 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 1805 { 1806 Obj_Entry objtmp; /* Temporary rtld object */ 1807 const Elf_Dyn *dyn_rpath; 1808 const Elf_Dyn *dyn_soname; 1809 const Elf_Dyn *dyn_runpath; 1810 1811 #ifdef RTLD_INIT_PAGESIZES_EARLY 1812 /* The page size is required by the dynamic memory allocator. */ 1813 init_pagesizes(aux_info); 1814 #endif 1815 1816 /* 1817 * Conjure up an Obj_Entry structure for the dynamic linker. 1818 * 1819 * The "path" member can't be initialized yet because string constants 1820 * cannot yet be accessed. Below we will set it correctly. 1821 */ 1822 memset(&objtmp, 0, sizeof(objtmp)); 1823 objtmp.path = NULL; 1824 objtmp.rtld = true; 1825 objtmp.mapbase = mapbase; 1826 #ifdef PIC 1827 objtmp.relocbase = mapbase; 1828 #endif 1829 if (RTLD_IS_DYNAMIC()) { 1830 objtmp.dynamic = rtld_dynamic(&objtmp); 1831 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 1832 assert(objtmp.needed == NULL); 1833 #if !defined(__mips__) 1834 /* MIPS has a bogus DT_TEXTREL. */ 1835 assert(!objtmp.textrel); 1836 #endif 1837 1838 /* 1839 * Temporarily put the dynamic linker entry into the object list, so 1840 * that symbols can be found. 1841 */ 1842 1843 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 1844 } 1845 1846 /* Initialize the object list. */ 1847 obj_tail = &obj_list; 1848 1849 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1850 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1851 1852 #ifndef RTLD_INIT_PAGESIZES_EARLY 1853 /* The page size is required by the dynamic memory allocator. */ 1854 init_pagesizes(aux_info); 1855 #endif 1856 1857 if (aux_info[AT_OSRELDATE] != NULL) 1858 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 1859 1860 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 1861 1862 /* Replace the path with a dynamically allocated copy. */ 1863 obj_rtld.path = xstrdup(PATH_RTLD); 1864 1865 r_debug.r_brk = r_debug_state; 1866 r_debug.r_state = RT_CONSISTENT; 1867 } 1868 1869 /* 1870 * Retrieve the array of supported page sizes. The kernel provides the page 1871 * sizes in increasing order. 1872 */ 1873 static void 1874 init_pagesizes(Elf_Auxinfo **aux_info) 1875 { 1876 static size_t psa[MAXPAGESIZES]; 1877 int mib[2]; 1878 size_t len, size; 1879 1880 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 1881 NULL) { 1882 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 1883 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 1884 } else { 1885 len = 2; 1886 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 1887 size = sizeof(psa); 1888 else { 1889 /* As a fallback, retrieve the base page size. */ 1890 size = sizeof(psa[0]); 1891 if (aux_info[AT_PAGESZ] != NULL) { 1892 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 1893 goto psa_filled; 1894 } else { 1895 mib[0] = CTL_HW; 1896 mib[1] = HW_PAGESIZE; 1897 len = 2; 1898 } 1899 } 1900 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 1901 _rtld_error("sysctl for hw.pagesize(s) failed"); 1902 die(); 1903 } 1904 psa_filled: 1905 pagesizes = psa; 1906 } 1907 npagesizes = size / sizeof(pagesizes[0]); 1908 /* Discard any invalid entries at the end of the array. */ 1909 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 1910 npagesizes--; 1911 } 1912 1913 /* 1914 * Add the init functions from a needed object list (and its recursive 1915 * needed objects) to "list". This is not used directly; it is a helper 1916 * function for initlist_add_objects(). The write lock must be held 1917 * when this function is called. 1918 */ 1919 static void 1920 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 1921 { 1922 /* Recursively process the successor needed objects. */ 1923 if (needed->next != NULL) 1924 initlist_add_neededs(needed->next, list); 1925 1926 /* Process the current needed object. */ 1927 if (needed->obj != NULL) 1928 initlist_add_objects(needed->obj, &needed->obj->next, list); 1929 } 1930 1931 /* 1932 * Scan all of the DAGs rooted in the range of objects from "obj" to 1933 * "tail" and add their init functions to "list". This recurses over 1934 * the DAGs and ensure the proper init ordering such that each object's 1935 * needed libraries are initialized before the object itself. At the 1936 * same time, this function adds the objects to the global finalization 1937 * list "list_fini" in the opposite order. The write lock must be 1938 * held when this function is called. 1939 */ 1940 static void 1941 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list) 1942 { 1943 1944 if (obj->init_scanned || obj->init_done) 1945 return; 1946 obj->init_scanned = true; 1947 1948 /* Recursively process the successor objects. */ 1949 if (&obj->next != tail) 1950 initlist_add_objects(obj->next, tail, list); 1951 1952 /* Recursively process the needed objects. */ 1953 if (obj->needed != NULL) 1954 initlist_add_neededs(obj->needed, list); 1955 if (obj->needed_filtees != NULL) 1956 initlist_add_neededs(obj->needed_filtees, list); 1957 if (obj->needed_aux_filtees != NULL) 1958 initlist_add_neededs(obj->needed_aux_filtees, list); 1959 1960 /* Add the object to the init list. */ 1961 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL || 1962 obj->init_array != (Elf_Addr)NULL) 1963 objlist_push_tail(list, obj); 1964 1965 /* Add the object to the global fini list in the reverse order. */ 1966 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 1967 && !obj->on_fini_list) { 1968 objlist_push_head(&list_fini, obj); 1969 obj->on_fini_list = true; 1970 } 1971 } 1972 1973 #ifndef FPTR_TARGET 1974 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 1975 #endif 1976 1977 static void 1978 free_needed_filtees(Needed_Entry *n) 1979 { 1980 Needed_Entry *needed, *needed1; 1981 1982 for (needed = n; needed != NULL; needed = needed->next) { 1983 if (needed->obj != NULL) { 1984 dlclose(needed->obj); 1985 needed->obj = NULL; 1986 } 1987 } 1988 for (needed = n; needed != NULL; needed = needed1) { 1989 needed1 = needed->next; 1990 free(needed); 1991 } 1992 } 1993 1994 static void 1995 unload_filtees(Obj_Entry *obj) 1996 { 1997 1998 free_needed_filtees(obj->needed_filtees); 1999 obj->needed_filtees = NULL; 2000 free_needed_filtees(obj->needed_aux_filtees); 2001 obj->needed_aux_filtees = NULL; 2002 obj->filtees_loaded = false; 2003 } 2004 2005 static void 2006 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2007 RtldLockState *lockstate) 2008 { 2009 2010 for (; needed != NULL; needed = needed->next) { 2011 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2012 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2013 RTLD_LOCAL, lockstate); 2014 } 2015 } 2016 2017 static void 2018 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2019 { 2020 2021 lock_restart_for_upgrade(lockstate); 2022 if (!obj->filtees_loaded) { 2023 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2024 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2025 obj->filtees_loaded = true; 2026 } 2027 } 2028 2029 static int 2030 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2031 { 2032 Obj_Entry *obj1; 2033 2034 for (; needed != NULL; needed = needed->next) { 2035 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2036 flags & ~RTLD_LO_NOLOAD); 2037 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2038 return (-1); 2039 } 2040 return (0); 2041 } 2042 2043 /* 2044 * Given a shared object, traverse its list of needed objects, and load 2045 * each of them. Returns 0 on success. Generates an error message and 2046 * returns -1 on failure. 2047 */ 2048 static int 2049 load_needed_objects(Obj_Entry *first, int flags) 2050 { 2051 Obj_Entry *obj; 2052 2053 for (obj = first; obj != NULL; obj = obj->next) { 2054 if (process_needed(obj, obj->needed, flags) == -1) 2055 return (-1); 2056 } 2057 return (0); 2058 } 2059 2060 static int 2061 load_preload_objects(void) 2062 { 2063 char *p = ld_preload; 2064 Obj_Entry *obj; 2065 static const char delim[] = " \t:;"; 2066 2067 if (p == NULL) 2068 return 0; 2069 2070 p += strspn(p, delim); 2071 while (*p != '\0') { 2072 size_t len = strcspn(p, delim); 2073 char savech; 2074 2075 savech = p[len]; 2076 p[len] = '\0'; 2077 obj = load_object(p, -1, NULL, 0); 2078 if (obj == NULL) 2079 return -1; /* XXX - cleanup */ 2080 obj->z_interpose = true; 2081 p[len] = savech; 2082 p += len; 2083 p += strspn(p, delim); 2084 } 2085 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2086 return 0; 2087 } 2088 2089 static const char * 2090 printable_path(const char *path) 2091 { 2092 2093 return (path == NULL ? "<unknown>" : path); 2094 } 2095 2096 /* 2097 * Load a shared object into memory, if it is not already loaded. The 2098 * object may be specified by name or by user-supplied file descriptor 2099 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2100 * duplicate is. 2101 * 2102 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2103 * on failure. 2104 */ 2105 static Obj_Entry * 2106 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2107 { 2108 Obj_Entry *obj; 2109 int fd; 2110 struct stat sb; 2111 char *path; 2112 2113 fd = -1; 2114 if (name != NULL) { 2115 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 2116 if (object_match_name(obj, name)) 2117 return (obj); 2118 } 2119 2120 path = find_library(name, refobj, &fd); 2121 if (path == NULL) 2122 return (NULL); 2123 } else 2124 path = NULL; 2125 2126 if (fd >= 0) { 2127 /* 2128 * search_library_pathfds() opens a fresh file descriptor for the 2129 * library, so there is no need to dup(). 2130 */ 2131 } else if (fd_u == -1) { 2132 /* 2133 * If we didn't find a match by pathname, or the name is not 2134 * supplied, open the file and check again by device and inode. 2135 * This avoids false mismatches caused by multiple links or ".." 2136 * in pathnames. 2137 * 2138 * To avoid a race, we open the file and use fstat() rather than 2139 * using stat(). 2140 */ 2141 if ((fd = open(path, O_RDONLY | O_CLOEXEC)) == -1) { 2142 _rtld_error("Cannot open \"%s\"", path); 2143 free(path); 2144 return (NULL); 2145 } 2146 } else { 2147 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2148 if (fd == -1) { 2149 _rtld_error("Cannot dup fd"); 2150 free(path); 2151 return (NULL); 2152 } 2153 } 2154 if (fstat(fd, &sb) == -1) { 2155 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2156 close(fd); 2157 free(path); 2158 return NULL; 2159 } 2160 for (obj = obj_list->next; obj != NULL; obj = obj->next) 2161 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2162 break; 2163 if (obj != NULL && name != NULL) { 2164 object_add_name(obj, name); 2165 free(path); 2166 close(fd); 2167 return obj; 2168 } 2169 if (flags & RTLD_LO_NOLOAD) { 2170 free(path); 2171 close(fd); 2172 return (NULL); 2173 } 2174 2175 /* First use of this object, so we must map it in */ 2176 obj = do_load_object(fd, name, path, &sb, flags); 2177 if (obj == NULL) 2178 free(path); 2179 close(fd); 2180 2181 return obj; 2182 } 2183 2184 static Obj_Entry * 2185 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2186 int flags) 2187 { 2188 Obj_Entry *obj; 2189 struct statfs fs; 2190 2191 /* 2192 * but first, make sure that environment variables haven't been 2193 * used to circumvent the noexec flag on a filesystem. 2194 */ 2195 if (dangerous_ld_env) { 2196 if (fstatfs(fd, &fs) != 0) { 2197 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2198 return NULL; 2199 } 2200 if (fs.f_flags & MNT_NOEXEC) { 2201 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 2202 return NULL; 2203 } 2204 } 2205 dbg("loading \"%s\"", printable_path(path)); 2206 obj = map_object(fd, printable_path(path), sbp); 2207 if (obj == NULL) 2208 return NULL; 2209 2210 /* 2211 * If DT_SONAME is present in the object, digest_dynamic2 already 2212 * added it to the object names. 2213 */ 2214 if (name != NULL) 2215 object_add_name(obj, name); 2216 obj->path = path; 2217 digest_dynamic(obj, 0); 2218 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2219 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2220 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2221 RTLD_LO_DLOPEN) { 2222 dbg("refusing to load non-loadable \"%s\"", obj->path); 2223 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2224 munmap(obj->mapbase, obj->mapsize); 2225 obj_free(obj); 2226 return (NULL); 2227 } 2228 2229 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2230 *obj_tail = obj; 2231 obj_tail = &obj->next; 2232 obj_count++; 2233 obj_loads++; 2234 linkmap_add(obj); /* for GDB & dlinfo() */ 2235 max_stack_flags |= obj->stack_flags; 2236 2237 dbg(" %p .. %p: %s", obj->mapbase, 2238 obj->mapbase + obj->mapsize - 1, obj->path); 2239 if (obj->textrel) 2240 dbg(" WARNING: %s has impure text", obj->path); 2241 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2242 obj->path); 2243 2244 return obj; 2245 } 2246 2247 static Obj_Entry * 2248 obj_from_addr(const void *addr) 2249 { 2250 Obj_Entry *obj; 2251 2252 for (obj = obj_list; obj != NULL; obj = obj->next) { 2253 if (addr < (void *) obj->mapbase) 2254 continue; 2255 if (addr < (void *) (obj->mapbase + obj->mapsize)) 2256 return obj; 2257 } 2258 return NULL; 2259 } 2260 2261 static void 2262 preinit_main(void) 2263 { 2264 Elf_Addr *preinit_addr; 2265 int index; 2266 2267 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2268 if (preinit_addr == NULL) 2269 return; 2270 2271 for (index = 0; index < obj_main->preinit_array_num; index++) { 2272 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2273 dbg("calling preinit function for %s at %p", obj_main->path, 2274 (void *)preinit_addr[index]); 2275 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2276 0, 0, obj_main->path); 2277 call_init_pointer(obj_main, preinit_addr[index]); 2278 } 2279 } 2280 } 2281 2282 /* 2283 * Call the finalization functions for each of the objects in "list" 2284 * belonging to the DAG of "root" and referenced once. If NULL "root" 2285 * is specified, every finalization function will be called regardless 2286 * of the reference count and the list elements won't be freed. All of 2287 * the objects are expected to have non-NULL fini functions. 2288 */ 2289 static void 2290 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2291 { 2292 Objlist_Entry *elm; 2293 char *saved_msg; 2294 Elf_Addr *fini_addr; 2295 int index; 2296 2297 assert(root == NULL || root->refcount == 1); 2298 2299 /* 2300 * Preserve the current error message since a fini function might 2301 * call into the dynamic linker and overwrite it. 2302 */ 2303 saved_msg = errmsg_save(); 2304 do { 2305 STAILQ_FOREACH(elm, list, link) { 2306 if (root != NULL && (elm->obj->refcount != 1 || 2307 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2308 continue; 2309 /* Remove object from fini list to prevent recursive invocation. */ 2310 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2311 /* 2312 * XXX: If a dlopen() call references an object while the 2313 * fini function is in progress, we might end up trying to 2314 * unload the referenced object in dlclose() or the object 2315 * won't be unloaded although its fini function has been 2316 * called. 2317 */ 2318 lock_release(rtld_bind_lock, lockstate); 2319 2320 /* 2321 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2322 * When this happens, DT_FINI_ARRAY is processed first. 2323 */ 2324 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2325 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2326 for (index = elm->obj->fini_array_num - 1; index >= 0; 2327 index--) { 2328 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2329 dbg("calling fini function for %s at %p", 2330 elm->obj->path, (void *)fini_addr[index]); 2331 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2332 (void *)fini_addr[index], 0, 0, elm->obj->path); 2333 call_initfini_pointer(elm->obj, fini_addr[index]); 2334 } 2335 } 2336 } 2337 if (elm->obj->fini != (Elf_Addr)NULL) { 2338 dbg("calling fini function for %s at %p", elm->obj->path, 2339 (void *)elm->obj->fini); 2340 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2341 0, 0, elm->obj->path); 2342 call_initfini_pointer(elm->obj, elm->obj->fini); 2343 } 2344 wlock_acquire(rtld_bind_lock, lockstate); 2345 /* No need to free anything if process is going down. */ 2346 if (root != NULL) 2347 free(elm); 2348 /* 2349 * We must restart the list traversal after every fini call 2350 * because a dlclose() call from the fini function or from 2351 * another thread might have modified the reference counts. 2352 */ 2353 break; 2354 } 2355 } while (elm != NULL); 2356 errmsg_restore(saved_msg); 2357 } 2358 2359 /* 2360 * Call the initialization functions for each of the objects in 2361 * "list". All of the objects are expected to have non-NULL init 2362 * functions. 2363 */ 2364 static void 2365 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2366 { 2367 Objlist_Entry *elm; 2368 Obj_Entry *obj; 2369 char *saved_msg; 2370 Elf_Addr *init_addr; 2371 int index; 2372 2373 /* 2374 * Clean init_scanned flag so that objects can be rechecked and 2375 * possibly initialized earlier if any of vectors called below 2376 * cause the change by using dlopen. 2377 */ 2378 for (obj = obj_list; obj != NULL; obj = obj->next) 2379 obj->init_scanned = false; 2380 2381 /* 2382 * Preserve the current error message since an init function might 2383 * call into the dynamic linker and overwrite it. 2384 */ 2385 saved_msg = errmsg_save(); 2386 STAILQ_FOREACH(elm, list, link) { 2387 if (elm->obj->init_done) /* Initialized early. */ 2388 continue; 2389 /* 2390 * Race: other thread might try to use this object before current 2391 * one completes the initilization. Not much can be done here 2392 * without better locking. 2393 */ 2394 elm->obj->init_done = true; 2395 lock_release(rtld_bind_lock, lockstate); 2396 2397 /* 2398 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2399 * When this happens, DT_INIT is processed first. 2400 */ 2401 if (elm->obj->init != (Elf_Addr)NULL) { 2402 dbg("calling init function for %s at %p", elm->obj->path, 2403 (void *)elm->obj->init); 2404 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2405 0, 0, elm->obj->path); 2406 call_initfini_pointer(elm->obj, elm->obj->init); 2407 } 2408 init_addr = (Elf_Addr *)elm->obj->init_array; 2409 if (init_addr != NULL) { 2410 for (index = 0; index < elm->obj->init_array_num; index++) { 2411 if (init_addr[index] != 0 && init_addr[index] != 1) { 2412 dbg("calling init function for %s at %p", elm->obj->path, 2413 (void *)init_addr[index]); 2414 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2415 (void *)init_addr[index], 0, 0, elm->obj->path); 2416 call_init_pointer(elm->obj, init_addr[index]); 2417 } 2418 } 2419 } 2420 wlock_acquire(rtld_bind_lock, lockstate); 2421 } 2422 errmsg_restore(saved_msg); 2423 } 2424 2425 static void 2426 objlist_clear(Objlist *list) 2427 { 2428 Objlist_Entry *elm; 2429 2430 while (!STAILQ_EMPTY(list)) { 2431 elm = STAILQ_FIRST(list); 2432 STAILQ_REMOVE_HEAD(list, link); 2433 free(elm); 2434 } 2435 } 2436 2437 static Objlist_Entry * 2438 objlist_find(Objlist *list, const Obj_Entry *obj) 2439 { 2440 Objlist_Entry *elm; 2441 2442 STAILQ_FOREACH(elm, list, link) 2443 if (elm->obj == obj) 2444 return elm; 2445 return NULL; 2446 } 2447 2448 static void 2449 objlist_init(Objlist *list) 2450 { 2451 STAILQ_INIT(list); 2452 } 2453 2454 static void 2455 objlist_push_head(Objlist *list, Obj_Entry *obj) 2456 { 2457 Objlist_Entry *elm; 2458 2459 elm = NEW(Objlist_Entry); 2460 elm->obj = obj; 2461 STAILQ_INSERT_HEAD(list, elm, link); 2462 } 2463 2464 static void 2465 objlist_push_tail(Objlist *list, Obj_Entry *obj) 2466 { 2467 Objlist_Entry *elm; 2468 2469 elm = NEW(Objlist_Entry); 2470 elm->obj = obj; 2471 STAILQ_INSERT_TAIL(list, elm, link); 2472 } 2473 2474 static void 2475 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2476 { 2477 Objlist_Entry *elm, *listelm; 2478 2479 STAILQ_FOREACH(listelm, list, link) { 2480 if (listelm->obj == listobj) 2481 break; 2482 } 2483 elm = NEW(Objlist_Entry); 2484 elm->obj = obj; 2485 if (listelm != NULL) 2486 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2487 else 2488 STAILQ_INSERT_TAIL(list, elm, link); 2489 } 2490 2491 static void 2492 objlist_remove(Objlist *list, Obj_Entry *obj) 2493 { 2494 Objlist_Entry *elm; 2495 2496 if ((elm = objlist_find(list, obj)) != NULL) { 2497 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2498 free(elm); 2499 } 2500 } 2501 2502 /* 2503 * Relocate dag rooted in the specified object. 2504 * Returns 0 on success, or -1 on failure. 2505 */ 2506 2507 static int 2508 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2509 int flags, RtldLockState *lockstate) 2510 { 2511 Objlist_Entry *elm; 2512 int error; 2513 2514 error = 0; 2515 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2516 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2517 lockstate); 2518 if (error == -1) 2519 break; 2520 } 2521 return (error); 2522 } 2523 2524 /* 2525 * Relocate single object. 2526 * Returns 0 on success, or -1 on failure. 2527 */ 2528 static int 2529 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2530 int flags, RtldLockState *lockstate) 2531 { 2532 2533 if (obj->relocated) 2534 return (0); 2535 obj->relocated = true; 2536 if (obj != rtldobj) 2537 dbg("relocating \"%s\"", obj->path); 2538 2539 if (obj->symtab == NULL || obj->strtab == NULL || 2540 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2541 _rtld_error("%s: Shared object has no run-time symbol table", 2542 obj->path); 2543 return (-1); 2544 } 2545 2546 if (obj->textrel) { 2547 /* There are relocations to the write-protected text segment. */ 2548 if (mprotect(obj->mapbase, obj->textsize, 2549 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) { 2550 _rtld_error("%s: Cannot write-enable text segment: %s", 2551 obj->path, rtld_strerror(errno)); 2552 return (-1); 2553 } 2554 } 2555 2556 /* Process the non-PLT non-IFUNC relocations. */ 2557 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2558 return (-1); 2559 2560 if (obj->textrel) { /* Re-protected the text segment. */ 2561 if (mprotect(obj->mapbase, obj->textsize, 2562 PROT_READ|PROT_EXEC) == -1) { 2563 _rtld_error("%s: Cannot write-protect text segment: %s", 2564 obj->path, rtld_strerror(errno)); 2565 return (-1); 2566 } 2567 } 2568 2569 /* Set the special PLT or GOT entries. */ 2570 init_pltgot(obj); 2571 2572 /* Process the PLT relocations. */ 2573 if (reloc_plt(obj) == -1) 2574 return (-1); 2575 /* Relocate the jump slots if we are doing immediate binding. */ 2576 if (obj->bind_now || bind_now) 2577 if (reloc_jmpslots(obj, flags, lockstate) == -1) 2578 return (-1); 2579 2580 /* 2581 * Process the non-PLT IFUNC relocations. The relocations are 2582 * processed in two phases, because IFUNC resolvers may 2583 * reference other symbols, which must be readily processed 2584 * before resolvers are called. 2585 */ 2586 if (obj->non_plt_gnu_ifunc && 2587 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate)) 2588 return (-1); 2589 2590 if (obj->relro_size > 0) { 2591 if (mprotect(obj->relro_page, obj->relro_size, 2592 PROT_READ) == -1) { 2593 _rtld_error("%s: Cannot enforce relro protection: %s", 2594 obj->path, rtld_strerror(errno)); 2595 return (-1); 2596 } 2597 } 2598 2599 /* 2600 * Set up the magic number and version in the Obj_Entry. These 2601 * were checked in the crt1.o from the original ElfKit, so we 2602 * set them for backward compatibility. 2603 */ 2604 obj->magic = RTLD_MAGIC; 2605 obj->version = RTLD_VERSION; 2606 2607 return (0); 2608 } 2609 2610 /* 2611 * Relocate newly-loaded shared objects. The argument is a pointer to 2612 * the Obj_Entry for the first such object. All objects from the first 2613 * to the end of the list of objects are relocated. Returns 0 on success, 2614 * or -1 on failure. 2615 */ 2616 static int 2617 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2618 int flags, RtldLockState *lockstate) 2619 { 2620 Obj_Entry *obj; 2621 int error; 2622 2623 for (error = 0, obj = first; obj != NULL; obj = obj->next) { 2624 error = relocate_object(obj, bind_now, rtldobj, flags, 2625 lockstate); 2626 if (error == -1) 2627 break; 2628 } 2629 return (error); 2630 } 2631 2632 /* 2633 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2634 * referencing STT_GNU_IFUNC symbols is postponed till the other 2635 * relocations are done. The indirect functions specified as 2636 * ifunc are allowed to call other symbols, so we need to have 2637 * objects relocated before asking for resolution from indirects. 2638 * 2639 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2640 * instead of the usual lazy handling of PLT slots. It is 2641 * consistent with how GNU does it. 2642 */ 2643 static int 2644 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2645 RtldLockState *lockstate) 2646 { 2647 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2648 return (-1); 2649 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2650 reloc_gnu_ifunc(obj, flags, lockstate) == -1) 2651 return (-1); 2652 return (0); 2653 } 2654 2655 static int 2656 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags, 2657 RtldLockState *lockstate) 2658 { 2659 Obj_Entry *obj; 2660 2661 for (obj = first; obj != NULL; obj = obj->next) { 2662 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1) 2663 return (-1); 2664 } 2665 return (0); 2666 } 2667 2668 static int 2669 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2670 RtldLockState *lockstate) 2671 { 2672 Objlist_Entry *elm; 2673 2674 STAILQ_FOREACH(elm, list, link) { 2675 if (resolve_object_ifunc(elm->obj, bind_now, flags, 2676 lockstate) == -1) 2677 return (-1); 2678 } 2679 return (0); 2680 } 2681 2682 /* 2683 * Cleanup procedure. It will be called (by the atexit mechanism) just 2684 * before the process exits. 2685 */ 2686 static void 2687 rtld_exit(void) 2688 { 2689 RtldLockState lockstate; 2690 2691 wlock_acquire(rtld_bind_lock, &lockstate); 2692 dbg("rtld_exit()"); 2693 objlist_call_fini(&list_fini, NULL, &lockstate); 2694 /* No need to remove the items from the list, since we are exiting. */ 2695 if (!libmap_disable) 2696 lm_fini(); 2697 lock_release(rtld_bind_lock, &lockstate); 2698 } 2699 2700 /* 2701 * Iterate over a search path, translate each element, and invoke the 2702 * callback on the result. 2703 */ 2704 static void * 2705 path_enumerate(const char *path, path_enum_proc callback, void *arg) 2706 { 2707 const char *trans; 2708 if (path == NULL) 2709 return (NULL); 2710 2711 path += strspn(path, ":;"); 2712 while (*path != '\0') { 2713 size_t len; 2714 char *res; 2715 2716 len = strcspn(path, ":;"); 2717 trans = lm_findn(NULL, path, len); 2718 if (trans) 2719 res = callback(trans, strlen(trans), arg); 2720 else 2721 res = callback(path, len, arg); 2722 2723 if (res != NULL) 2724 return (res); 2725 2726 path += len; 2727 path += strspn(path, ":;"); 2728 } 2729 2730 return (NULL); 2731 } 2732 2733 struct try_library_args { 2734 const char *name; 2735 size_t namelen; 2736 char *buffer; 2737 size_t buflen; 2738 }; 2739 2740 static void * 2741 try_library_path(const char *dir, size_t dirlen, void *param) 2742 { 2743 struct try_library_args *arg; 2744 2745 arg = param; 2746 if (*dir == '/' || trust) { 2747 char *pathname; 2748 2749 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 2750 return (NULL); 2751 2752 pathname = arg->buffer; 2753 strncpy(pathname, dir, dirlen); 2754 pathname[dirlen] = '/'; 2755 strcpy(pathname + dirlen + 1, arg->name); 2756 2757 dbg(" Trying \"%s\"", pathname); 2758 if (access(pathname, F_OK) == 0) { /* We found it */ 2759 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 2760 strcpy(pathname, arg->buffer); 2761 return (pathname); 2762 } 2763 } 2764 return (NULL); 2765 } 2766 2767 static char * 2768 search_library_path(const char *name, const char *path) 2769 { 2770 char *p; 2771 struct try_library_args arg; 2772 2773 if (path == NULL) 2774 return NULL; 2775 2776 arg.name = name; 2777 arg.namelen = strlen(name); 2778 arg.buffer = xmalloc(PATH_MAX); 2779 arg.buflen = PATH_MAX; 2780 2781 p = path_enumerate(path, try_library_path, &arg); 2782 2783 free(arg.buffer); 2784 2785 return (p); 2786 } 2787 2788 2789 /* 2790 * Finds the library with the given name using the directory descriptors 2791 * listed in the LD_LIBRARY_PATH_FDS environment variable. 2792 * 2793 * Returns a freshly-opened close-on-exec file descriptor for the library, 2794 * or -1 if the library cannot be found. 2795 */ 2796 static char * 2797 search_library_pathfds(const char *name, const char *path, int *fdp) 2798 { 2799 char *envcopy, *fdstr, *found, *last_token; 2800 size_t len; 2801 int dirfd, fd; 2802 2803 dbg("%s('%s', '%s', fdp)", __func__, name, path); 2804 2805 /* Don't load from user-specified libdirs into setuid binaries. */ 2806 if (!trust) 2807 return (NULL); 2808 2809 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 2810 if (path == NULL) 2811 return (NULL); 2812 2813 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 2814 if (name[0] == '/') { 2815 dbg("Absolute path (%s) passed to %s", name, __func__); 2816 return (NULL); 2817 } 2818 2819 /* 2820 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 2821 * copy of the path, as strtok_r rewrites separator tokens 2822 * with '\0'. 2823 */ 2824 found = NULL; 2825 envcopy = xstrdup(path); 2826 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 2827 fdstr = strtok_r(NULL, ":", &last_token)) { 2828 dirfd = parse_libdir(fdstr); 2829 if (dirfd < 0) 2830 break; 2831 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC); 2832 if (fd >= 0) { 2833 *fdp = fd; 2834 len = strlen(fdstr) + strlen(name) + 3; 2835 found = xmalloc(len); 2836 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 2837 _rtld_error("error generating '%d/%s'", 2838 dirfd, name); 2839 die(); 2840 } 2841 dbg("open('%s') => %d", found, fd); 2842 break; 2843 } 2844 } 2845 free(envcopy); 2846 2847 return (found); 2848 } 2849 2850 2851 int 2852 dlclose(void *handle) 2853 { 2854 Obj_Entry *root; 2855 RtldLockState lockstate; 2856 2857 wlock_acquire(rtld_bind_lock, &lockstate); 2858 root = dlcheck(handle); 2859 if (root == NULL) { 2860 lock_release(rtld_bind_lock, &lockstate); 2861 return -1; 2862 } 2863 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 2864 root->path); 2865 2866 /* Unreference the object and its dependencies. */ 2867 root->dl_refcount--; 2868 2869 if (root->refcount == 1) { 2870 /* 2871 * The object will be no longer referenced, so we must unload it. 2872 * First, call the fini functions. 2873 */ 2874 objlist_call_fini(&list_fini, root, &lockstate); 2875 2876 unref_dag(root); 2877 2878 /* Finish cleaning up the newly-unreferenced objects. */ 2879 GDB_STATE(RT_DELETE,&root->linkmap); 2880 unload_object(root); 2881 GDB_STATE(RT_CONSISTENT,NULL); 2882 } else 2883 unref_dag(root); 2884 2885 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 2886 lock_release(rtld_bind_lock, &lockstate); 2887 return 0; 2888 } 2889 2890 char * 2891 dlerror(void) 2892 { 2893 char *msg = error_message; 2894 error_message = NULL; 2895 return msg; 2896 } 2897 2898 /* 2899 * This function is deprecated and has no effect. 2900 */ 2901 void 2902 dllockinit(void *context, 2903 void *(*lock_create)(void *context), 2904 void (*rlock_acquire)(void *lock), 2905 void (*wlock_acquire)(void *lock), 2906 void (*lock_release)(void *lock), 2907 void (*lock_destroy)(void *lock), 2908 void (*context_destroy)(void *context)) 2909 { 2910 static void *cur_context; 2911 static void (*cur_context_destroy)(void *); 2912 2913 /* Just destroy the context from the previous call, if necessary. */ 2914 if (cur_context_destroy != NULL) 2915 cur_context_destroy(cur_context); 2916 cur_context = context; 2917 cur_context_destroy = context_destroy; 2918 } 2919 2920 void * 2921 dlopen(const char *name, int mode) 2922 { 2923 2924 return (rtld_dlopen(name, -1, mode)); 2925 } 2926 2927 void * 2928 fdlopen(int fd, int mode) 2929 { 2930 2931 return (rtld_dlopen(NULL, fd, mode)); 2932 } 2933 2934 static void * 2935 rtld_dlopen(const char *name, int fd, int mode) 2936 { 2937 RtldLockState lockstate; 2938 int lo_flags; 2939 2940 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 2941 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 2942 if (ld_tracing != NULL) { 2943 rlock_acquire(rtld_bind_lock, &lockstate); 2944 if (sigsetjmp(lockstate.env, 0) != 0) 2945 lock_upgrade(rtld_bind_lock, &lockstate); 2946 environ = (char **)*get_program_var_addr("environ", &lockstate); 2947 lock_release(rtld_bind_lock, &lockstate); 2948 } 2949 lo_flags = RTLD_LO_DLOPEN; 2950 if (mode & RTLD_NODELETE) 2951 lo_flags |= RTLD_LO_NODELETE; 2952 if (mode & RTLD_NOLOAD) 2953 lo_flags |= RTLD_LO_NOLOAD; 2954 if (ld_tracing != NULL) 2955 lo_flags |= RTLD_LO_TRACE; 2956 2957 return (dlopen_object(name, fd, obj_main, lo_flags, 2958 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 2959 } 2960 2961 static void 2962 dlopen_cleanup(Obj_Entry *obj) 2963 { 2964 2965 obj->dl_refcount--; 2966 unref_dag(obj); 2967 if (obj->refcount == 0) 2968 unload_object(obj); 2969 } 2970 2971 static Obj_Entry * 2972 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 2973 int mode, RtldLockState *lockstate) 2974 { 2975 Obj_Entry **old_obj_tail; 2976 Obj_Entry *obj; 2977 Objlist initlist; 2978 RtldLockState mlockstate; 2979 int result; 2980 2981 objlist_init(&initlist); 2982 2983 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 2984 wlock_acquire(rtld_bind_lock, &mlockstate); 2985 lockstate = &mlockstate; 2986 } 2987 GDB_STATE(RT_ADD,NULL); 2988 2989 old_obj_tail = obj_tail; 2990 obj = NULL; 2991 if (name == NULL && fd == -1) { 2992 obj = obj_main; 2993 obj->refcount++; 2994 } else { 2995 obj = load_object(name, fd, refobj, lo_flags); 2996 } 2997 2998 if (obj) { 2999 obj->dl_refcount++; 3000 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3001 objlist_push_tail(&list_global, obj); 3002 if (*old_obj_tail != NULL) { /* We loaded something new. */ 3003 assert(*old_obj_tail == obj); 3004 result = load_needed_objects(obj, 3005 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 3006 init_dag(obj); 3007 ref_dag(obj); 3008 if (result != -1) 3009 result = rtld_verify_versions(&obj->dagmembers); 3010 if (result != -1 && ld_tracing) 3011 goto trace; 3012 if (result == -1 || relocate_object_dag(obj, 3013 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3014 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3015 lockstate) == -1) { 3016 dlopen_cleanup(obj); 3017 obj = NULL; 3018 } else if (lo_flags & RTLD_LO_EARLY) { 3019 /* 3020 * Do not call the init functions for early loaded 3021 * filtees. The image is still not initialized enough 3022 * for them to work. 3023 * 3024 * Our object is found by the global object list and 3025 * will be ordered among all init calls done right 3026 * before transferring control to main. 3027 */ 3028 } else { 3029 /* Make list of init functions to call. */ 3030 initlist_add_objects(obj, &obj->next, &initlist); 3031 } 3032 /* 3033 * Process all no_delete objects here, given them own 3034 * DAGs to prevent their dependencies from being unloaded. 3035 * This has to be done after we have loaded all of the 3036 * dependencies, so that we do not miss any. 3037 */ 3038 if (obj != NULL) 3039 process_nodelete(obj); 3040 } else { 3041 /* 3042 * Bump the reference counts for objects on this DAG. If 3043 * this is the first dlopen() call for the object that was 3044 * already loaded as a dependency, initialize the dag 3045 * starting at it. 3046 */ 3047 init_dag(obj); 3048 ref_dag(obj); 3049 3050 if ((lo_flags & RTLD_LO_TRACE) != 0) 3051 goto trace; 3052 } 3053 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3054 obj->z_nodelete) && !obj->ref_nodel) { 3055 dbg("obj %s nodelete", obj->path); 3056 ref_dag(obj); 3057 obj->z_nodelete = obj->ref_nodel = true; 3058 } 3059 } 3060 3061 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3062 name); 3063 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3064 3065 if (!(lo_flags & RTLD_LO_EARLY)) { 3066 map_stacks_exec(lockstate); 3067 } 3068 3069 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3070 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3071 lockstate) == -1) { 3072 objlist_clear(&initlist); 3073 dlopen_cleanup(obj); 3074 if (lockstate == &mlockstate) 3075 lock_release(rtld_bind_lock, lockstate); 3076 return (NULL); 3077 } 3078 3079 if (!(lo_flags & RTLD_LO_EARLY)) { 3080 /* Call the init functions. */ 3081 objlist_call_init(&initlist, lockstate); 3082 } 3083 objlist_clear(&initlist); 3084 if (lockstate == &mlockstate) 3085 lock_release(rtld_bind_lock, lockstate); 3086 return obj; 3087 trace: 3088 trace_loaded_objects(obj); 3089 if (lockstate == &mlockstate) 3090 lock_release(rtld_bind_lock, lockstate); 3091 exit(0); 3092 } 3093 3094 static void * 3095 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3096 int flags) 3097 { 3098 DoneList donelist; 3099 const Obj_Entry *obj, *defobj; 3100 const Elf_Sym *def; 3101 SymLook req; 3102 RtldLockState lockstate; 3103 tls_index ti; 3104 void *sym; 3105 int res; 3106 3107 def = NULL; 3108 defobj = NULL; 3109 symlook_init(&req, name); 3110 req.ventry = ve; 3111 req.flags = flags | SYMLOOK_IN_PLT; 3112 req.lockstate = &lockstate; 3113 3114 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3115 rlock_acquire(rtld_bind_lock, &lockstate); 3116 if (sigsetjmp(lockstate.env, 0) != 0) 3117 lock_upgrade(rtld_bind_lock, &lockstate); 3118 if (handle == NULL || handle == RTLD_NEXT || 3119 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3120 3121 if ((obj = obj_from_addr(retaddr)) == NULL) { 3122 _rtld_error("Cannot determine caller's shared object"); 3123 lock_release(rtld_bind_lock, &lockstate); 3124 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3125 return NULL; 3126 } 3127 if (handle == NULL) { /* Just the caller's shared object. */ 3128 res = symlook_obj(&req, obj); 3129 if (res == 0) { 3130 def = req.sym_out; 3131 defobj = req.defobj_out; 3132 } 3133 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3134 handle == RTLD_SELF) { /* ... caller included */ 3135 if (handle == RTLD_NEXT) 3136 obj = obj->next; 3137 for (; obj != NULL; obj = obj->next) { 3138 res = symlook_obj(&req, obj); 3139 if (res == 0) { 3140 if (def == NULL || 3141 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3142 def = req.sym_out; 3143 defobj = req.defobj_out; 3144 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3145 break; 3146 } 3147 } 3148 } 3149 /* 3150 * Search the dynamic linker itself, and possibly resolve the 3151 * symbol from there. This is how the application links to 3152 * dynamic linker services such as dlopen. 3153 */ 3154 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3155 res = symlook_obj(&req, &obj_rtld); 3156 if (res == 0) { 3157 def = req.sym_out; 3158 defobj = req.defobj_out; 3159 } 3160 } 3161 } else { 3162 assert(handle == RTLD_DEFAULT); 3163 res = symlook_default(&req, obj); 3164 if (res == 0) { 3165 defobj = req.defobj_out; 3166 def = req.sym_out; 3167 } 3168 } 3169 } else { 3170 if ((obj = dlcheck(handle)) == NULL) { 3171 lock_release(rtld_bind_lock, &lockstate); 3172 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3173 return NULL; 3174 } 3175 3176 donelist_init(&donelist); 3177 if (obj->mainprog) { 3178 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3179 res = symlook_global(&req, &donelist); 3180 if (res == 0) { 3181 def = req.sym_out; 3182 defobj = req.defobj_out; 3183 } 3184 /* 3185 * Search the dynamic linker itself, and possibly resolve the 3186 * symbol from there. This is how the application links to 3187 * dynamic linker services such as dlopen. 3188 */ 3189 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3190 res = symlook_obj(&req, &obj_rtld); 3191 if (res == 0) { 3192 def = req.sym_out; 3193 defobj = req.defobj_out; 3194 } 3195 } 3196 } 3197 else { 3198 /* Search the whole DAG rooted at the given object. */ 3199 res = symlook_list(&req, &obj->dagmembers, &donelist); 3200 if (res == 0) { 3201 def = req.sym_out; 3202 defobj = req.defobj_out; 3203 } 3204 } 3205 } 3206 3207 if (def != NULL) { 3208 lock_release(rtld_bind_lock, &lockstate); 3209 3210 /* 3211 * The value required by the caller is derived from the value 3212 * of the symbol. this is simply the relocated value of the 3213 * symbol. 3214 */ 3215 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3216 sym = make_function_pointer(def, defobj); 3217 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3218 sym = rtld_resolve_ifunc(defobj, def); 3219 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3220 ti.ti_module = defobj->tlsindex; 3221 ti.ti_offset = def->st_value; 3222 sym = __tls_get_addr(&ti); 3223 } else 3224 sym = defobj->relocbase + def->st_value; 3225 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3226 return (sym); 3227 } 3228 3229 _rtld_error("Undefined symbol \"%s\"", name); 3230 lock_release(rtld_bind_lock, &lockstate); 3231 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3232 return NULL; 3233 } 3234 3235 void * 3236 dlsym(void *handle, const char *name) 3237 { 3238 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3239 SYMLOOK_DLSYM); 3240 } 3241 3242 dlfunc_t 3243 dlfunc(void *handle, const char *name) 3244 { 3245 union { 3246 void *d; 3247 dlfunc_t f; 3248 } rv; 3249 3250 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3251 SYMLOOK_DLSYM); 3252 return (rv.f); 3253 } 3254 3255 void * 3256 dlvsym(void *handle, const char *name, const char *version) 3257 { 3258 Ver_Entry ventry; 3259 3260 ventry.name = version; 3261 ventry.file = NULL; 3262 ventry.hash = elf_hash(version); 3263 ventry.flags= 0; 3264 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3265 SYMLOOK_DLSYM); 3266 } 3267 3268 int 3269 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3270 { 3271 const Obj_Entry *obj; 3272 RtldLockState lockstate; 3273 3274 rlock_acquire(rtld_bind_lock, &lockstate); 3275 obj = obj_from_addr(addr); 3276 if (obj == NULL) { 3277 _rtld_error("No shared object contains address"); 3278 lock_release(rtld_bind_lock, &lockstate); 3279 return (0); 3280 } 3281 rtld_fill_dl_phdr_info(obj, phdr_info); 3282 lock_release(rtld_bind_lock, &lockstate); 3283 return (1); 3284 } 3285 3286 int 3287 dladdr(const void *addr, Dl_info *info) 3288 { 3289 const Obj_Entry *obj; 3290 const Elf_Sym *def; 3291 void *symbol_addr; 3292 unsigned long symoffset; 3293 RtldLockState lockstate; 3294 3295 rlock_acquire(rtld_bind_lock, &lockstate); 3296 obj = obj_from_addr(addr); 3297 if (obj == NULL) { 3298 _rtld_error("No shared object contains address"); 3299 lock_release(rtld_bind_lock, &lockstate); 3300 return 0; 3301 } 3302 info->dli_fname = obj->path; 3303 info->dli_fbase = obj->mapbase; 3304 info->dli_saddr = (void *)0; 3305 info->dli_sname = NULL; 3306 3307 /* 3308 * Walk the symbol list looking for the symbol whose address is 3309 * closest to the address sent in. 3310 */ 3311 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3312 def = obj->symtab + symoffset; 3313 3314 /* 3315 * For skip the symbol if st_shndx is either SHN_UNDEF or 3316 * SHN_COMMON. 3317 */ 3318 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3319 continue; 3320 3321 /* 3322 * If the symbol is greater than the specified address, or if it 3323 * is further away from addr than the current nearest symbol, 3324 * then reject it. 3325 */ 3326 symbol_addr = obj->relocbase + def->st_value; 3327 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3328 continue; 3329 3330 /* Update our idea of the nearest symbol. */ 3331 info->dli_sname = obj->strtab + def->st_name; 3332 info->dli_saddr = symbol_addr; 3333 3334 /* Exact match? */ 3335 if (info->dli_saddr == addr) 3336 break; 3337 } 3338 lock_release(rtld_bind_lock, &lockstate); 3339 return 1; 3340 } 3341 3342 int 3343 dlinfo(void *handle, int request, void *p) 3344 { 3345 const Obj_Entry *obj; 3346 RtldLockState lockstate; 3347 int error; 3348 3349 rlock_acquire(rtld_bind_lock, &lockstate); 3350 3351 if (handle == NULL || handle == RTLD_SELF) { 3352 void *retaddr; 3353 3354 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3355 if ((obj = obj_from_addr(retaddr)) == NULL) 3356 _rtld_error("Cannot determine caller's shared object"); 3357 } else 3358 obj = dlcheck(handle); 3359 3360 if (obj == NULL) { 3361 lock_release(rtld_bind_lock, &lockstate); 3362 return (-1); 3363 } 3364 3365 error = 0; 3366 switch (request) { 3367 case RTLD_DI_LINKMAP: 3368 *((struct link_map const **)p) = &obj->linkmap; 3369 break; 3370 case RTLD_DI_ORIGIN: 3371 error = rtld_dirname(obj->path, p); 3372 break; 3373 3374 case RTLD_DI_SERINFOSIZE: 3375 case RTLD_DI_SERINFO: 3376 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3377 break; 3378 3379 default: 3380 _rtld_error("Invalid request %d passed to dlinfo()", request); 3381 error = -1; 3382 } 3383 3384 lock_release(rtld_bind_lock, &lockstate); 3385 3386 return (error); 3387 } 3388 3389 static void 3390 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3391 { 3392 3393 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3394 phdr_info->dlpi_name = obj->path; 3395 phdr_info->dlpi_phdr = obj->phdr; 3396 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3397 phdr_info->dlpi_tls_modid = obj->tlsindex; 3398 phdr_info->dlpi_tls_data = obj->tlsinit; 3399 phdr_info->dlpi_adds = obj_loads; 3400 phdr_info->dlpi_subs = obj_loads - obj_count; 3401 } 3402 3403 int 3404 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3405 { 3406 struct dl_phdr_info phdr_info; 3407 const Obj_Entry *obj; 3408 RtldLockState bind_lockstate, phdr_lockstate; 3409 int error; 3410 3411 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3412 rlock_acquire(rtld_bind_lock, &bind_lockstate); 3413 3414 error = 0; 3415 3416 for (obj = obj_list; obj != NULL; obj = obj->next) { 3417 rtld_fill_dl_phdr_info(obj, &phdr_info); 3418 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0) 3419 break; 3420 3421 } 3422 if (error == 0) { 3423 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3424 error = callback(&phdr_info, sizeof(phdr_info), param); 3425 } 3426 3427 lock_release(rtld_bind_lock, &bind_lockstate); 3428 lock_release(rtld_phdr_lock, &phdr_lockstate); 3429 3430 return (error); 3431 } 3432 3433 static void * 3434 fill_search_info(const char *dir, size_t dirlen, void *param) 3435 { 3436 struct fill_search_info_args *arg; 3437 3438 arg = param; 3439 3440 if (arg->request == RTLD_DI_SERINFOSIZE) { 3441 arg->serinfo->dls_cnt ++; 3442 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3443 } else { 3444 struct dl_serpath *s_entry; 3445 3446 s_entry = arg->serpath; 3447 s_entry->dls_name = arg->strspace; 3448 s_entry->dls_flags = arg->flags; 3449 3450 strncpy(arg->strspace, dir, dirlen); 3451 arg->strspace[dirlen] = '\0'; 3452 3453 arg->strspace += dirlen + 1; 3454 arg->serpath++; 3455 } 3456 3457 return (NULL); 3458 } 3459 3460 static int 3461 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3462 { 3463 struct dl_serinfo _info; 3464 struct fill_search_info_args args; 3465 3466 args.request = RTLD_DI_SERINFOSIZE; 3467 args.serinfo = &_info; 3468 3469 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3470 _info.dls_cnt = 0; 3471 3472 path_enumerate(obj->rpath, fill_search_info, &args); 3473 path_enumerate(ld_library_path, fill_search_info, &args); 3474 path_enumerate(obj->runpath, fill_search_info, &args); 3475 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args); 3476 if (!obj->z_nodeflib) 3477 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 3478 3479 3480 if (request == RTLD_DI_SERINFOSIZE) { 3481 info->dls_size = _info.dls_size; 3482 info->dls_cnt = _info.dls_cnt; 3483 return (0); 3484 } 3485 3486 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3487 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3488 return (-1); 3489 } 3490 3491 args.request = RTLD_DI_SERINFO; 3492 args.serinfo = info; 3493 args.serpath = &info->dls_serpath[0]; 3494 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3495 3496 args.flags = LA_SER_RUNPATH; 3497 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 3498 return (-1); 3499 3500 args.flags = LA_SER_LIBPATH; 3501 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 3502 return (-1); 3503 3504 args.flags = LA_SER_RUNPATH; 3505 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL) 3506 return (-1); 3507 3508 args.flags = LA_SER_CONFIG; 3509 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args) 3510 != NULL) 3511 return (-1); 3512 3513 args.flags = LA_SER_DEFAULT; 3514 if (!obj->z_nodeflib && 3515 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 3516 return (-1); 3517 return (0); 3518 } 3519 3520 static int 3521 rtld_dirname(const char *path, char *bname) 3522 { 3523 const char *endp; 3524 3525 /* Empty or NULL string gets treated as "." */ 3526 if (path == NULL || *path == '\0') { 3527 bname[0] = '.'; 3528 bname[1] = '\0'; 3529 return (0); 3530 } 3531 3532 /* Strip trailing slashes */ 3533 endp = path + strlen(path) - 1; 3534 while (endp > path && *endp == '/') 3535 endp--; 3536 3537 /* Find the start of the dir */ 3538 while (endp > path && *endp != '/') 3539 endp--; 3540 3541 /* Either the dir is "/" or there are no slashes */ 3542 if (endp == path) { 3543 bname[0] = *endp == '/' ? '/' : '.'; 3544 bname[1] = '\0'; 3545 return (0); 3546 } else { 3547 do { 3548 endp--; 3549 } while (endp > path && *endp == '/'); 3550 } 3551 3552 if (endp - path + 2 > PATH_MAX) 3553 { 3554 _rtld_error("Filename is too long: %s", path); 3555 return(-1); 3556 } 3557 3558 strncpy(bname, path, endp - path + 1); 3559 bname[endp - path + 1] = '\0'; 3560 return (0); 3561 } 3562 3563 static int 3564 rtld_dirname_abs(const char *path, char *base) 3565 { 3566 char base_rel[PATH_MAX]; 3567 3568 if (rtld_dirname(path, base) == -1) 3569 return (-1); 3570 if (base[0] == '/') 3571 return (0); 3572 if (getcwd(base_rel, sizeof(base_rel)) == NULL || 3573 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) || 3574 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel)) 3575 return (-1); 3576 strcpy(base, base_rel); 3577 return (0); 3578 } 3579 3580 static void 3581 linkmap_add(Obj_Entry *obj) 3582 { 3583 struct link_map *l = &obj->linkmap; 3584 struct link_map *prev; 3585 3586 obj->linkmap.l_name = obj->path; 3587 obj->linkmap.l_addr = obj->mapbase; 3588 obj->linkmap.l_ld = obj->dynamic; 3589 #ifdef __mips__ 3590 /* GDB needs load offset on MIPS to use the symbols */ 3591 obj->linkmap.l_offs = obj->relocbase; 3592 #endif 3593 3594 if (r_debug.r_map == NULL) { 3595 r_debug.r_map = l; 3596 return; 3597 } 3598 3599 /* 3600 * Scan to the end of the list, but not past the entry for the 3601 * dynamic linker, which we want to keep at the very end. 3602 */ 3603 for (prev = r_debug.r_map; 3604 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3605 prev = prev->l_next) 3606 ; 3607 3608 /* Link in the new entry. */ 3609 l->l_prev = prev; 3610 l->l_next = prev->l_next; 3611 if (l->l_next != NULL) 3612 l->l_next->l_prev = l; 3613 prev->l_next = l; 3614 } 3615 3616 static void 3617 linkmap_delete(Obj_Entry *obj) 3618 { 3619 struct link_map *l = &obj->linkmap; 3620 3621 if (l->l_prev == NULL) { 3622 if ((r_debug.r_map = l->l_next) != NULL) 3623 l->l_next->l_prev = NULL; 3624 return; 3625 } 3626 3627 if ((l->l_prev->l_next = l->l_next) != NULL) 3628 l->l_next->l_prev = l->l_prev; 3629 } 3630 3631 /* 3632 * Function for the debugger to set a breakpoint on to gain control. 3633 * 3634 * The two parameters allow the debugger to easily find and determine 3635 * what the runtime loader is doing and to whom it is doing it. 3636 * 3637 * When the loadhook trap is hit (r_debug_state, set at program 3638 * initialization), the arguments can be found on the stack: 3639 * 3640 * +8 struct link_map *m 3641 * +4 struct r_debug *rd 3642 * +0 RetAddr 3643 */ 3644 void 3645 r_debug_state(struct r_debug* rd, struct link_map *m) 3646 { 3647 /* 3648 * The following is a hack to force the compiler to emit calls to 3649 * this function, even when optimizing. If the function is empty, 3650 * the compiler is not obliged to emit any code for calls to it, 3651 * even when marked __noinline. However, gdb depends on those 3652 * calls being made. 3653 */ 3654 __compiler_membar(); 3655 } 3656 3657 /* 3658 * A function called after init routines have completed. This can be used to 3659 * break before a program's entry routine is called, and can be used when 3660 * main is not available in the symbol table. 3661 */ 3662 void 3663 _r_debug_postinit(struct link_map *m) 3664 { 3665 3666 /* See r_debug_state(). */ 3667 __compiler_membar(); 3668 } 3669 3670 /* 3671 * Get address of the pointer variable in the main program. 3672 * Prefer non-weak symbol over the weak one. 3673 */ 3674 static const void ** 3675 get_program_var_addr(const char *name, RtldLockState *lockstate) 3676 { 3677 SymLook req; 3678 DoneList donelist; 3679 3680 symlook_init(&req, name); 3681 req.lockstate = lockstate; 3682 donelist_init(&donelist); 3683 if (symlook_global(&req, &donelist) != 0) 3684 return (NULL); 3685 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 3686 return ((const void **)make_function_pointer(req.sym_out, 3687 req.defobj_out)); 3688 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 3689 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 3690 else 3691 return ((const void **)(req.defobj_out->relocbase + 3692 req.sym_out->st_value)); 3693 } 3694 3695 /* 3696 * Set a pointer variable in the main program to the given value. This 3697 * is used to set key variables such as "environ" before any of the 3698 * init functions are called. 3699 */ 3700 static void 3701 set_program_var(const char *name, const void *value) 3702 { 3703 const void **addr; 3704 3705 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 3706 dbg("\"%s\": *%p <-- %p", name, addr, value); 3707 *addr = value; 3708 } 3709 } 3710 3711 /* 3712 * Search the global objects, including dependencies and main object, 3713 * for the given symbol. 3714 */ 3715 static int 3716 symlook_global(SymLook *req, DoneList *donelist) 3717 { 3718 SymLook req1; 3719 const Objlist_Entry *elm; 3720 int res; 3721 3722 symlook_init_from_req(&req1, req); 3723 3724 /* Search all objects loaded at program start up. */ 3725 if (req->defobj_out == NULL || 3726 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3727 res = symlook_list(&req1, &list_main, donelist); 3728 if (res == 0 && (req->defobj_out == NULL || 3729 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3730 req->sym_out = req1.sym_out; 3731 req->defobj_out = req1.defobj_out; 3732 assert(req->defobj_out != NULL); 3733 } 3734 } 3735 3736 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 3737 STAILQ_FOREACH(elm, &list_global, link) { 3738 if (req->defobj_out != NULL && 3739 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3740 break; 3741 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 3742 if (res == 0 && (req->defobj_out == NULL || 3743 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3744 req->sym_out = req1.sym_out; 3745 req->defobj_out = req1.defobj_out; 3746 assert(req->defobj_out != NULL); 3747 } 3748 } 3749 3750 return (req->sym_out != NULL ? 0 : ESRCH); 3751 } 3752 3753 /* 3754 * Given a symbol name in a referencing object, find the corresponding 3755 * definition of the symbol. Returns a pointer to the symbol, or NULL if 3756 * no definition was found. Returns a pointer to the Obj_Entry of the 3757 * defining object via the reference parameter DEFOBJ_OUT. 3758 */ 3759 static int 3760 symlook_default(SymLook *req, const Obj_Entry *refobj) 3761 { 3762 DoneList donelist; 3763 const Objlist_Entry *elm; 3764 SymLook req1; 3765 int res; 3766 3767 donelist_init(&donelist); 3768 symlook_init_from_req(&req1, req); 3769 3770 /* Look first in the referencing object if linked symbolically. */ 3771 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 3772 res = symlook_obj(&req1, refobj); 3773 if (res == 0) { 3774 req->sym_out = req1.sym_out; 3775 req->defobj_out = req1.defobj_out; 3776 assert(req->defobj_out != NULL); 3777 } 3778 } 3779 3780 symlook_global(req, &donelist); 3781 3782 /* Search all dlopened DAGs containing the referencing object. */ 3783 STAILQ_FOREACH(elm, &refobj->dldags, link) { 3784 if (req->sym_out != NULL && 3785 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3786 break; 3787 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 3788 if (res == 0 && (req->sym_out == NULL || 3789 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3790 req->sym_out = req1.sym_out; 3791 req->defobj_out = req1.defobj_out; 3792 assert(req->defobj_out != NULL); 3793 } 3794 } 3795 3796 /* 3797 * Search the dynamic linker itself, and possibly resolve the 3798 * symbol from there. This is how the application links to 3799 * dynamic linker services such as dlopen. 3800 */ 3801 if (req->sym_out == NULL || 3802 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3803 res = symlook_obj(&req1, &obj_rtld); 3804 if (res == 0) { 3805 req->sym_out = req1.sym_out; 3806 req->defobj_out = req1.defobj_out; 3807 assert(req->defobj_out != NULL); 3808 } 3809 } 3810 3811 return (req->sym_out != NULL ? 0 : ESRCH); 3812 } 3813 3814 static int 3815 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 3816 { 3817 const Elf_Sym *def; 3818 const Obj_Entry *defobj; 3819 const Objlist_Entry *elm; 3820 SymLook req1; 3821 int res; 3822 3823 def = NULL; 3824 defobj = NULL; 3825 STAILQ_FOREACH(elm, objlist, link) { 3826 if (donelist_check(dlp, elm->obj)) 3827 continue; 3828 symlook_init_from_req(&req1, req); 3829 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 3830 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3831 def = req1.sym_out; 3832 defobj = req1.defobj_out; 3833 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3834 break; 3835 } 3836 } 3837 } 3838 if (def != NULL) { 3839 req->sym_out = def; 3840 req->defobj_out = defobj; 3841 return (0); 3842 } 3843 return (ESRCH); 3844 } 3845 3846 /* 3847 * Search the chain of DAGS cointed to by the given Needed_Entry 3848 * for a symbol of the given name. Each DAG is scanned completely 3849 * before advancing to the next one. Returns a pointer to the symbol, 3850 * or NULL if no definition was found. 3851 */ 3852 static int 3853 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 3854 { 3855 const Elf_Sym *def; 3856 const Needed_Entry *n; 3857 const Obj_Entry *defobj; 3858 SymLook req1; 3859 int res; 3860 3861 def = NULL; 3862 defobj = NULL; 3863 symlook_init_from_req(&req1, req); 3864 for (n = needed; n != NULL; n = n->next) { 3865 if (n->obj == NULL || 3866 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 3867 continue; 3868 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3869 def = req1.sym_out; 3870 defobj = req1.defobj_out; 3871 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3872 break; 3873 } 3874 } 3875 if (def != NULL) { 3876 req->sym_out = def; 3877 req->defobj_out = defobj; 3878 return (0); 3879 } 3880 return (ESRCH); 3881 } 3882 3883 /* 3884 * Search the symbol table of a single shared object for a symbol of 3885 * the given name and version, if requested. Returns a pointer to the 3886 * symbol, or NULL if no definition was found. If the object is 3887 * filter, return filtered symbol from filtee. 3888 * 3889 * The symbol's hash value is passed in for efficiency reasons; that 3890 * eliminates many recomputations of the hash value. 3891 */ 3892 int 3893 symlook_obj(SymLook *req, const Obj_Entry *obj) 3894 { 3895 DoneList donelist; 3896 SymLook req1; 3897 int flags, res, mres; 3898 3899 /* 3900 * If there is at least one valid hash at this point, we prefer to 3901 * use the faster GNU version if available. 3902 */ 3903 if (obj->valid_hash_gnu) 3904 mres = symlook_obj1_gnu(req, obj); 3905 else if (obj->valid_hash_sysv) 3906 mres = symlook_obj1_sysv(req, obj); 3907 else 3908 return (EINVAL); 3909 3910 if (mres == 0) { 3911 if (obj->needed_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_filtees, &donelist); 3917 if (res == 0) { 3918 req->sym_out = req1.sym_out; 3919 req->defobj_out = req1.defobj_out; 3920 } 3921 return (res); 3922 } 3923 if (obj->needed_aux_filtees != NULL) { 3924 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3925 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3926 donelist_init(&donelist); 3927 symlook_init_from_req(&req1, req); 3928 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 3929 if (res == 0) { 3930 req->sym_out = req1.sym_out; 3931 req->defobj_out = req1.defobj_out; 3932 return (res); 3933 } 3934 } 3935 } 3936 return (mres); 3937 } 3938 3939 /* Symbol match routine common to both hash functions */ 3940 static bool 3941 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 3942 const unsigned long symnum) 3943 { 3944 Elf_Versym verndx; 3945 const Elf_Sym *symp; 3946 const char *strp; 3947 3948 symp = obj->symtab + symnum; 3949 strp = obj->strtab + symp->st_name; 3950 3951 switch (ELF_ST_TYPE(symp->st_info)) { 3952 case STT_FUNC: 3953 case STT_NOTYPE: 3954 case STT_OBJECT: 3955 case STT_COMMON: 3956 case STT_GNU_IFUNC: 3957 if (symp->st_value == 0) 3958 return (false); 3959 /* fallthrough */ 3960 case STT_TLS: 3961 if (symp->st_shndx != SHN_UNDEF) 3962 break; 3963 #ifndef __mips__ 3964 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 3965 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 3966 break; 3967 /* fallthrough */ 3968 #endif 3969 default: 3970 return (false); 3971 } 3972 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 3973 return (false); 3974 3975 if (req->ventry == NULL) { 3976 if (obj->versyms != NULL) { 3977 verndx = VER_NDX(obj->versyms[symnum]); 3978 if (verndx > obj->vernum) { 3979 _rtld_error( 3980 "%s: symbol %s references wrong version %d", 3981 obj->path, obj->strtab + symnum, verndx); 3982 return (false); 3983 } 3984 /* 3985 * If we are not called from dlsym (i.e. this 3986 * is a normal relocation from unversioned 3987 * binary), accept the symbol immediately if 3988 * it happens to have first version after this 3989 * shared object became versioned. Otherwise, 3990 * if symbol is versioned and not hidden, 3991 * remember it. If it is the only symbol with 3992 * this name exported by the shared object, it 3993 * will be returned as a match by the calling 3994 * function. If symbol is global (verndx < 2) 3995 * accept it unconditionally. 3996 */ 3997 if ((req->flags & SYMLOOK_DLSYM) == 0 && 3998 verndx == VER_NDX_GIVEN) { 3999 result->sym_out = symp; 4000 return (true); 4001 } 4002 else if (verndx >= VER_NDX_GIVEN) { 4003 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4004 == 0) { 4005 if (result->vsymp == NULL) 4006 result->vsymp = symp; 4007 result->vcount++; 4008 } 4009 return (false); 4010 } 4011 } 4012 result->sym_out = symp; 4013 return (true); 4014 } 4015 if (obj->versyms == NULL) { 4016 if (object_match_name(obj, req->ventry->name)) { 4017 _rtld_error("%s: object %s should provide version %s " 4018 "for symbol %s", obj_rtld.path, obj->path, 4019 req->ventry->name, obj->strtab + symnum); 4020 return (false); 4021 } 4022 } else { 4023 verndx = VER_NDX(obj->versyms[symnum]); 4024 if (verndx > obj->vernum) { 4025 _rtld_error("%s: symbol %s references wrong version %d", 4026 obj->path, obj->strtab + symnum, verndx); 4027 return (false); 4028 } 4029 if (obj->vertab[verndx].hash != req->ventry->hash || 4030 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4031 /* 4032 * Version does not match. Look if this is a 4033 * global symbol and if it is not hidden. If 4034 * global symbol (verndx < 2) is available, 4035 * use it. Do not return symbol if we are 4036 * called by dlvsym, because dlvsym looks for 4037 * a specific version and default one is not 4038 * what dlvsym wants. 4039 */ 4040 if ((req->flags & SYMLOOK_DLSYM) || 4041 (verndx >= VER_NDX_GIVEN) || 4042 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4043 return (false); 4044 } 4045 } 4046 result->sym_out = symp; 4047 return (true); 4048 } 4049 4050 /* 4051 * Search for symbol using SysV hash function. 4052 * obj->buckets is known not to be NULL at this point; the test for this was 4053 * performed with the obj->valid_hash_sysv assignment. 4054 */ 4055 static int 4056 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4057 { 4058 unsigned long symnum; 4059 Sym_Match_Result matchres; 4060 4061 matchres.sym_out = NULL; 4062 matchres.vsymp = NULL; 4063 matchres.vcount = 0; 4064 4065 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4066 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4067 if (symnum >= obj->nchains) 4068 return (ESRCH); /* Bad object */ 4069 4070 if (matched_symbol(req, obj, &matchres, symnum)) { 4071 req->sym_out = matchres.sym_out; 4072 req->defobj_out = obj; 4073 return (0); 4074 } 4075 } 4076 if (matchres.vcount == 1) { 4077 req->sym_out = matchres.vsymp; 4078 req->defobj_out = obj; 4079 return (0); 4080 } 4081 return (ESRCH); 4082 } 4083 4084 /* Search for symbol using GNU hash function */ 4085 static int 4086 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4087 { 4088 Elf_Addr bloom_word; 4089 const Elf32_Word *hashval; 4090 Elf32_Word bucket; 4091 Sym_Match_Result matchres; 4092 unsigned int h1, h2; 4093 unsigned long symnum; 4094 4095 matchres.sym_out = NULL; 4096 matchres.vsymp = NULL; 4097 matchres.vcount = 0; 4098 4099 /* Pick right bitmask word from Bloom filter array */ 4100 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4101 obj->maskwords_bm_gnu]; 4102 4103 /* Calculate modulus word size of gnu hash and its derivative */ 4104 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4105 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4106 4107 /* Filter out the "definitely not in set" queries */ 4108 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4109 return (ESRCH); 4110 4111 /* Locate hash chain and corresponding value element*/ 4112 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4113 if (bucket == 0) 4114 return (ESRCH); 4115 hashval = &obj->chain_zero_gnu[bucket]; 4116 do { 4117 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4118 symnum = hashval - obj->chain_zero_gnu; 4119 if (matched_symbol(req, obj, &matchres, symnum)) { 4120 req->sym_out = matchres.sym_out; 4121 req->defobj_out = obj; 4122 return (0); 4123 } 4124 } 4125 } while ((*hashval++ & 1) == 0); 4126 if (matchres.vcount == 1) { 4127 req->sym_out = matchres.vsymp; 4128 req->defobj_out = obj; 4129 return (0); 4130 } 4131 return (ESRCH); 4132 } 4133 4134 static void 4135 trace_loaded_objects(Obj_Entry *obj) 4136 { 4137 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4138 int c; 4139 4140 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 4141 main_local = ""; 4142 4143 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL) 4144 fmt1 = "\t%o => %p (%x)\n"; 4145 4146 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL) 4147 fmt2 = "\t%o (%x)\n"; 4148 4149 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL"); 4150 4151 for (; obj; obj = obj->next) { 4152 Needed_Entry *needed; 4153 char *name, *path; 4154 bool is_lib; 4155 4156 if (list_containers && obj->needed != NULL) 4157 rtld_printf("%s:\n", obj->path); 4158 for (needed = obj->needed; needed; needed = needed->next) { 4159 if (needed->obj != NULL) { 4160 if (needed->obj->traced && !list_containers) 4161 continue; 4162 needed->obj->traced = true; 4163 path = needed->obj->path; 4164 } else 4165 path = "not found"; 4166 4167 name = (char *)obj->strtab + needed->name; 4168 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4169 4170 fmt = is_lib ? fmt1 : fmt2; 4171 while ((c = *fmt++) != '\0') { 4172 switch (c) { 4173 default: 4174 rtld_putchar(c); 4175 continue; 4176 case '\\': 4177 switch (c = *fmt) { 4178 case '\0': 4179 continue; 4180 case 'n': 4181 rtld_putchar('\n'); 4182 break; 4183 case 't': 4184 rtld_putchar('\t'); 4185 break; 4186 } 4187 break; 4188 case '%': 4189 switch (c = *fmt) { 4190 case '\0': 4191 continue; 4192 case '%': 4193 default: 4194 rtld_putchar(c); 4195 break; 4196 case 'A': 4197 rtld_putstr(main_local); 4198 break; 4199 case 'a': 4200 rtld_putstr(obj_main->path); 4201 break; 4202 case 'o': 4203 rtld_putstr(name); 4204 break; 4205 #if 0 4206 case 'm': 4207 rtld_printf("%d", sodp->sod_major); 4208 break; 4209 case 'n': 4210 rtld_printf("%d", sodp->sod_minor); 4211 break; 4212 #endif 4213 case 'p': 4214 rtld_putstr(path); 4215 break; 4216 case 'x': 4217 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4218 0); 4219 break; 4220 } 4221 break; 4222 } 4223 ++fmt; 4224 } 4225 } 4226 } 4227 } 4228 4229 /* 4230 * Unload a dlopened object and its dependencies from memory and from 4231 * our data structures. It is assumed that the DAG rooted in the 4232 * object has already been unreferenced, and that the object has a 4233 * reference count of 0. 4234 */ 4235 static void 4236 unload_object(Obj_Entry *root) 4237 { 4238 Obj_Entry *obj; 4239 Obj_Entry **linkp; 4240 4241 assert(root->refcount == 0); 4242 4243 /* 4244 * Pass over the DAG removing unreferenced objects from 4245 * appropriate lists. 4246 */ 4247 unlink_object(root); 4248 4249 /* Unmap all objects that are no longer referenced. */ 4250 linkp = &obj_list->next; 4251 while ((obj = *linkp) != NULL) { 4252 if (obj->refcount == 0) { 4253 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 4254 obj->path); 4255 dbg("unloading \"%s\"", obj->path); 4256 unload_filtees(root); 4257 munmap(obj->mapbase, obj->mapsize); 4258 linkmap_delete(obj); 4259 *linkp = obj->next; 4260 obj_count--; 4261 obj_free(obj); 4262 } else 4263 linkp = &obj->next; 4264 } 4265 obj_tail = linkp; 4266 } 4267 4268 static void 4269 unlink_object(Obj_Entry *root) 4270 { 4271 Objlist_Entry *elm; 4272 4273 if (root->refcount == 0) { 4274 /* Remove the object from the RTLD_GLOBAL list. */ 4275 objlist_remove(&list_global, root); 4276 4277 /* Remove the object from all objects' DAG lists. */ 4278 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4279 objlist_remove(&elm->obj->dldags, root); 4280 if (elm->obj != root) 4281 unlink_object(elm->obj); 4282 } 4283 } 4284 } 4285 4286 static void 4287 ref_dag(Obj_Entry *root) 4288 { 4289 Objlist_Entry *elm; 4290 4291 assert(root->dag_inited); 4292 STAILQ_FOREACH(elm, &root->dagmembers, link) 4293 elm->obj->refcount++; 4294 } 4295 4296 static void 4297 unref_dag(Obj_Entry *root) 4298 { 4299 Objlist_Entry *elm; 4300 4301 assert(root->dag_inited); 4302 STAILQ_FOREACH(elm, &root->dagmembers, link) 4303 elm->obj->refcount--; 4304 } 4305 4306 /* 4307 * Common code for MD __tls_get_addr(). 4308 */ 4309 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4310 static void * 4311 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4312 { 4313 Elf_Addr *newdtv, *dtv; 4314 RtldLockState lockstate; 4315 int to_copy; 4316 4317 dtv = *dtvp; 4318 /* Check dtv generation in case new modules have arrived */ 4319 if (dtv[0] != tls_dtv_generation) { 4320 wlock_acquire(rtld_bind_lock, &lockstate); 4321 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4322 to_copy = dtv[1]; 4323 if (to_copy > tls_max_index) 4324 to_copy = tls_max_index; 4325 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4326 newdtv[0] = tls_dtv_generation; 4327 newdtv[1] = tls_max_index; 4328 free(dtv); 4329 lock_release(rtld_bind_lock, &lockstate); 4330 dtv = *dtvp = newdtv; 4331 } 4332 4333 /* Dynamically allocate module TLS if necessary */ 4334 if (dtv[index + 1] == 0) { 4335 /* Signal safe, wlock will block out signals. */ 4336 wlock_acquire(rtld_bind_lock, &lockstate); 4337 if (!dtv[index + 1]) 4338 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4339 lock_release(rtld_bind_lock, &lockstate); 4340 } 4341 return ((void *)(dtv[index + 1] + offset)); 4342 } 4343 4344 void * 4345 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4346 { 4347 Elf_Addr *dtv; 4348 4349 dtv = *dtvp; 4350 /* Check dtv generation in case new modules have arrived */ 4351 if (__predict_true(dtv[0] == tls_dtv_generation && 4352 dtv[index + 1] != 0)) 4353 return ((void *)(dtv[index + 1] + offset)); 4354 return (tls_get_addr_slow(dtvp, index, offset)); 4355 } 4356 4357 #if defined(__arm__) || defined(__mips__) || defined(__powerpc__) 4358 4359 /* 4360 * Allocate Static TLS using the Variant I method. 4361 */ 4362 void * 4363 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4364 { 4365 Obj_Entry *obj; 4366 char *tcb; 4367 Elf_Addr **tls; 4368 Elf_Addr *dtv; 4369 Elf_Addr addr; 4370 int i; 4371 4372 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4373 return (oldtcb); 4374 4375 assert(tcbsize >= TLS_TCB_SIZE); 4376 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 4377 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 4378 4379 if (oldtcb != NULL) { 4380 memcpy(tls, oldtcb, tls_static_space); 4381 free(oldtcb); 4382 4383 /* Adjust the DTV. */ 4384 dtv = tls[0]; 4385 for (i = 0; i < dtv[1]; i++) { 4386 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4387 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4388 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 4389 } 4390 } 4391 } else { 4392 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4393 tls[0] = dtv; 4394 dtv[0] = tls_dtv_generation; 4395 dtv[1] = tls_max_index; 4396 4397 for (obj = objs; obj; obj = obj->next) { 4398 if (obj->tlsoffset > 0) { 4399 addr = (Elf_Addr)tls + obj->tlsoffset; 4400 if (obj->tlsinitsize > 0) 4401 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4402 if (obj->tlssize > obj->tlsinitsize) 4403 memset((void*) (addr + obj->tlsinitsize), 0, 4404 obj->tlssize - obj->tlsinitsize); 4405 dtv[obj->tlsindex + 1] = addr; 4406 } 4407 } 4408 } 4409 4410 return (tcb); 4411 } 4412 4413 void 4414 free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4415 { 4416 Elf_Addr *dtv; 4417 Elf_Addr tlsstart, tlsend; 4418 int dtvsize, i; 4419 4420 assert(tcbsize >= TLS_TCB_SIZE); 4421 4422 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 4423 tlsend = tlsstart + tls_static_space; 4424 4425 dtv = *(Elf_Addr **)tlsstart; 4426 dtvsize = dtv[1]; 4427 for (i = 0; i < dtvsize; i++) { 4428 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4429 free((void*)dtv[i+2]); 4430 } 4431 } 4432 free(dtv); 4433 free(tcb); 4434 } 4435 4436 #endif 4437 4438 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 4439 4440 /* 4441 * Allocate Static TLS using the Variant II method. 4442 */ 4443 void * 4444 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4445 { 4446 Obj_Entry *obj; 4447 size_t size, ralign; 4448 char *tls; 4449 Elf_Addr *dtv, *olddtv; 4450 Elf_Addr segbase, oldsegbase, addr; 4451 int i; 4452 4453 ralign = tcbalign; 4454 if (tls_static_max_align > ralign) 4455 ralign = tls_static_max_align; 4456 size = round(tls_static_space, ralign) + round(tcbsize, ralign); 4457 4458 assert(tcbsize >= 2*sizeof(Elf_Addr)); 4459 tls = malloc_aligned(size, ralign); 4460 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4461 4462 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign)); 4463 ((Elf_Addr*)segbase)[0] = segbase; 4464 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 4465 4466 dtv[0] = tls_dtv_generation; 4467 dtv[1] = tls_max_index; 4468 4469 if (oldtls) { 4470 /* 4471 * Copy the static TLS block over whole. 4472 */ 4473 oldsegbase = (Elf_Addr) oldtls; 4474 memcpy((void *)(segbase - tls_static_space), 4475 (const void *)(oldsegbase - tls_static_space), 4476 tls_static_space); 4477 4478 /* 4479 * If any dynamic TLS blocks have been created tls_get_addr(), 4480 * move them over. 4481 */ 4482 olddtv = ((Elf_Addr**)oldsegbase)[1]; 4483 for (i = 0; i < olddtv[1]; i++) { 4484 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 4485 dtv[i+2] = olddtv[i+2]; 4486 olddtv[i+2] = 0; 4487 } 4488 } 4489 4490 /* 4491 * We assume that this block was the one we created with 4492 * allocate_initial_tls(). 4493 */ 4494 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 4495 } else { 4496 for (obj = objs; obj; obj = obj->next) { 4497 if (obj->tlsoffset) { 4498 addr = segbase - obj->tlsoffset; 4499 memset((void*) (addr + obj->tlsinitsize), 4500 0, obj->tlssize - obj->tlsinitsize); 4501 if (obj->tlsinit) 4502 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4503 dtv[obj->tlsindex + 1] = addr; 4504 } 4505 } 4506 } 4507 4508 return (void*) segbase; 4509 } 4510 4511 void 4512 free_tls(void *tls, size_t tcbsize, size_t tcbalign) 4513 { 4514 Elf_Addr* dtv; 4515 size_t size, ralign; 4516 int dtvsize, i; 4517 Elf_Addr tlsstart, tlsend; 4518 4519 /* 4520 * Figure out the size of the initial TLS block so that we can 4521 * find stuff which ___tls_get_addr() allocated dynamically. 4522 */ 4523 ralign = tcbalign; 4524 if (tls_static_max_align > ralign) 4525 ralign = tls_static_max_align; 4526 size = round(tls_static_space, ralign); 4527 4528 dtv = ((Elf_Addr**)tls)[1]; 4529 dtvsize = dtv[1]; 4530 tlsend = (Elf_Addr) tls; 4531 tlsstart = tlsend - size; 4532 for (i = 0; i < dtvsize; i++) { 4533 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 4534 free_aligned((void *)dtv[i + 2]); 4535 } 4536 } 4537 4538 free_aligned((void *)tlsstart); 4539 free((void*) dtv); 4540 } 4541 4542 #endif 4543 4544 /* 4545 * Allocate TLS block for module with given index. 4546 */ 4547 void * 4548 allocate_module_tls(int index) 4549 { 4550 Obj_Entry* obj; 4551 char* p; 4552 4553 for (obj = obj_list; obj; obj = obj->next) { 4554 if (obj->tlsindex == index) 4555 break; 4556 } 4557 if (!obj) { 4558 _rtld_error("Can't find module with TLS index %d", index); 4559 die(); 4560 } 4561 4562 p = malloc_aligned(obj->tlssize, obj->tlsalign); 4563 memcpy(p, obj->tlsinit, obj->tlsinitsize); 4564 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 4565 4566 return p; 4567 } 4568 4569 bool 4570 allocate_tls_offset(Obj_Entry *obj) 4571 { 4572 size_t off; 4573 4574 if (obj->tls_done) 4575 return true; 4576 4577 if (obj->tlssize == 0) { 4578 obj->tls_done = true; 4579 return true; 4580 } 4581 4582 if (obj->tlsindex == 1) 4583 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 4584 else 4585 off = calculate_tls_offset(tls_last_offset, tls_last_size, 4586 obj->tlssize, obj->tlsalign); 4587 4588 /* 4589 * If we have already fixed the size of the static TLS block, we 4590 * must stay within that size. When allocating the static TLS, we 4591 * leave a small amount of space spare to be used for dynamically 4592 * loading modules which use static TLS. 4593 */ 4594 if (tls_static_space != 0) { 4595 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 4596 return false; 4597 } else if (obj->tlsalign > tls_static_max_align) { 4598 tls_static_max_align = obj->tlsalign; 4599 } 4600 4601 tls_last_offset = obj->tlsoffset = off; 4602 tls_last_size = obj->tlssize; 4603 obj->tls_done = true; 4604 4605 return true; 4606 } 4607 4608 void 4609 free_tls_offset(Obj_Entry *obj) 4610 { 4611 4612 /* 4613 * If we were the last thing to allocate out of the static TLS 4614 * block, we give our space back to the 'allocator'. This is a 4615 * simplistic workaround to allow libGL.so.1 to be loaded and 4616 * unloaded multiple times. 4617 */ 4618 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 4619 == calculate_tls_end(tls_last_offset, tls_last_size)) { 4620 tls_last_offset -= obj->tlssize; 4621 tls_last_size = 0; 4622 } 4623 } 4624 4625 void * 4626 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 4627 { 4628 void *ret; 4629 RtldLockState lockstate; 4630 4631 wlock_acquire(rtld_bind_lock, &lockstate); 4632 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign); 4633 lock_release(rtld_bind_lock, &lockstate); 4634 return (ret); 4635 } 4636 4637 void 4638 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4639 { 4640 RtldLockState lockstate; 4641 4642 wlock_acquire(rtld_bind_lock, &lockstate); 4643 free_tls(tcb, tcbsize, tcbalign); 4644 lock_release(rtld_bind_lock, &lockstate); 4645 } 4646 4647 static void 4648 object_add_name(Obj_Entry *obj, const char *name) 4649 { 4650 Name_Entry *entry; 4651 size_t len; 4652 4653 len = strlen(name); 4654 entry = malloc(sizeof(Name_Entry) + len); 4655 4656 if (entry != NULL) { 4657 strcpy(entry->name, name); 4658 STAILQ_INSERT_TAIL(&obj->names, entry, link); 4659 } 4660 } 4661 4662 static int 4663 object_match_name(const Obj_Entry *obj, const char *name) 4664 { 4665 Name_Entry *entry; 4666 4667 STAILQ_FOREACH(entry, &obj->names, link) { 4668 if (strcmp(name, entry->name) == 0) 4669 return (1); 4670 } 4671 return (0); 4672 } 4673 4674 static Obj_Entry * 4675 locate_dependency(const Obj_Entry *obj, const char *name) 4676 { 4677 const Objlist_Entry *entry; 4678 const Needed_Entry *needed; 4679 4680 STAILQ_FOREACH(entry, &list_main, link) { 4681 if (object_match_name(entry->obj, name)) 4682 return entry->obj; 4683 } 4684 4685 for (needed = obj->needed; needed != NULL; needed = needed->next) { 4686 if (strcmp(obj->strtab + needed->name, name) == 0 || 4687 (needed->obj != NULL && object_match_name(needed->obj, name))) { 4688 /* 4689 * If there is DT_NEEDED for the name we are looking for, 4690 * we are all set. Note that object might not be found if 4691 * dependency was not loaded yet, so the function can 4692 * return NULL here. This is expected and handled 4693 * properly by the caller. 4694 */ 4695 return (needed->obj); 4696 } 4697 } 4698 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 4699 obj->path, name); 4700 die(); 4701 } 4702 4703 static int 4704 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 4705 const Elf_Vernaux *vna) 4706 { 4707 const Elf_Verdef *vd; 4708 const char *vername; 4709 4710 vername = refobj->strtab + vna->vna_name; 4711 vd = depobj->verdef; 4712 if (vd == NULL) { 4713 _rtld_error("%s: version %s required by %s not defined", 4714 depobj->path, vername, refobj->path); 4715 return (-1); 4716 } 4717 for (;;) { 4718 if (vd->vd_version != VER_DEF_CURRENT) { 4719 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4720 depobj->path, vd->vd_version); 4721 return (-1); 4722 } 4723 if (vna->vna_hash == vd->vd_hash) { 4724 const Elf_Verdaux *aux = (const Elf_Verdaux *) 4725 ((char *)vd + vd->vd_aux); 4726 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 4727 return (0); 4728 } 4729 if (vd->vd_next == 0) 4730 break; 4731 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4732 } 4733 if (vna->vna_flags & VER_FLG_WEAK) 4734 return (0); 4735 _rtld_error("%s: version %s required by %s not found", 4736 depobj->path, vername, refobj->path); 4737 return (-1); 4738 } 4739 4740 static int 4741 rtld_verify_object_versions(Obj_Entry *obj) 4742 { 4743 const Elf_Verneed *vn; 4744 const Elf_Verdef *vd; 4745 const Elf_Verdaux *vda; 4746 const Elf_Vernaux *vna; 4747 const Obj_Entry *depobj; 4748 int maxvernum, vernum; 4749 4750 if (obj->ver_checked) 4751 return (0); 4752 obj->ver_checked = true; 4753 4754 maxvernum = 0; 4755 /* 4756 * Walk over defined and required version records and figure out 4757 * max index used by any of them. Do very basic sanity checking 4758 * while there. 4759 */ 4760 vn = obj->verneed; 4761 while (vn != NULL) { 4762 if (vn->vn_version != VER_NEED_CURRENT) { 4763 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 4764 obj->path, vn->vn_version); 4765 return (-1); 4766 } 4767 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4768 for (;;) { 4769 vernum = VER_NEED_IDX(vna->vna_other); 4770 if (vernum > maxvernum) 4771 maxvernum = vernum; 4772 if (vna->vna_next == 0) 4773 break; 4774 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4775 } 4776 if (vn->vn_next == 0) 4777 break; 4778 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4779 } 4780 4781 vd = obj->verdef; 4782 while (vd != NULL) { 4783 if (vd->vd_version != VER_DEF_CURRENT) { 4784 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4785 obj->path, vd->vd_version); 4786 return (-1); 4787 } 4788 vernum = VER_DEF_IDX(vd->vd_ndx); 4789 if (vernum > maxvernum) 4790 maxvernum = vernum; 4791 if (vd->vd_next == 0) 4792 break; 4793 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4794 } 4795 4796 if (maxvernum == 0) 4797 return (0); 4798 4799 /* 4800 * Store version information in array indexable by version index. 4801 * Verify that object version requirements are satisfied along the 4802 * way. 4803 */ 4804 obj->vernum = maxvernum + 1; 4805 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 4806 4807 vd = obj->verdef; 4808 while (vd != NULL) { 4809 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 4810 vernum = VER_DEF_IDX(vd->vd_ndx); 4811 assert(vernum <= maxvernum); 4812 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 4813 obj->vertab[vernum].hash = vd->vd_hash; 4814 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 4815 obj->vertab[vernum].file = NULL; 4816 obj->vertab[vernum].flags = 0; 4817 } 4818 if (vd->vd_next == 0) 4819 break; 4820 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4821 } 4822 4823 vn = obj->verneed; 4824 while (vn != NULL) { 4825 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 4826 if (depobj == NULL) 4827 return (-1); 4828 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4829 for (;;) { 4830 if (check_object_provided_version(obj, depobj, vna)) 4831 return (-1); 4832 vernum = VER_NEED_IDX(vna->vna_other); 4833 assert(vernum <= maxvernum); 4834 obj->vertab[vernum].hash = vna->vna_hash; 4835 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 4836 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 4837 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 4838 VER_INFO_HIDDEN : 0; 4839 if (vna->vna_next == 0) 4840 break; 4841 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4842 } 4843 if (vn->vn_next == 0) 4844 break; 4845 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4846 } 4847 return 0; 4848 } 4849 4850 static int 4851 rtld_verify_versions(const Objlist *objlist) 4852 { 4853 Objlist_Entry *entry; 4854 int rc; 4855 4856 rc = 0; 4857 STAILQ_FOREACH(entry, objlist, link) { 4858 /* 4859 * Skip dummy objects or objects that have their version requirements 4860 * already checked. 4861 */ 4862 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 4863 continue; 4864 if (rtld_verify_object_versions(entry->obj) == -1) { 4865 rc = -1; 4866 if (ld_tracing == NULL) 4867 break; 4868 } 4869 } 4870 if (rc == 0 || ld_tracing != NULL) 4871 rc = rtld_verify_object_versions(&obj_rtld); 4872 return rc; 4873 } 4874 4875 const Ver_Entry * 4876 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 4877 { 4878 Elf_Versym vernum; 4879 4880 if (obj->vertab) { 4881 vernum = VER_NDX(obj->versyms[symnum]); 4882 if (vernum >= obj->vernum) { 4883 _rtld_error("%s: symbol %s has wrong verneed value %d", 4884 obj->path, obj->strtab + symnum, vernum); 4885 } else if (obj->vertab[vernum].hash != 0) { 4886 return &obj->vertab[vernum]; 4887 } 4888 } 4889 return NULL; 4890 } 4891 4892 int 4893 _rtld_get_stack_prot(void) 4894 { 4895 4896 return (stack_prot); 4897 } 4898 4899 int 4900 _rtld_is_dlopened(void *arg) 4901 { 4902 Obj_Entry *obj; 4903 RtldLockState lockstate; 4904 int res; 4905 4906 rlock_acquire(rtld_bind_lock, &lockstate); 4907 obj = dlcheck(arg); 4908 if (obj == NULL) 4909 obj = obj_from_addr(arg); 4910 if (obj == NULL) { 4911 _rtld_error("No shared object contains address"); 4912 lock_release(rtld_bind_lock, &lockstate); 4913 return (-1); 4914 } 4915 res = obj->dlopened ? 1 : 0; 4916 lock_release(rtld_bind_lock, &lockstate); 4917 return (res); 4918 } 4919 4920 static void 4921 map_stacks_exec(RtldLockState *lockstate) 4922 { 4923 void (*thr_map_stacks_exec)(void); 4924 4925 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 4926 return; 4927 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 4928 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 4929 if (thr_map_stacks_exec != NULL) { 4930 stack_prot |= PROT_EXEC; 4931 thr_map_stacks_exec(); 4932 } 4933 } 4934 4935 void 4936 symlook_init(SymLook *dst, const char *name) 4937 { 4938 4939 bzero(dst, sizeof(*dst)); 4940 dst->name = name; 4941 dst->hash = elf_hash(name); 4942 dst->hash_gnu = gnu_hash(name); 4943 } 4944 4945 static void 4946 symlook_init_from_req(SymLook *dst, const SymLook *src) 4947 { 4948 4949 dst->name = src->name; 4950 dst->hash = src->hash; 4951 dst->hash_gnu = src->hash_gnu; 4952 dst->ventry = src->ventry; 4953 dst->flags = src->flags; 4954 dst->defobj_out = NULL; 4955 dst->sym_out = NULL; 4956 dst->lockstate = src->lockstate; 4957 } 4958 4959 4960 /* 4961 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 4962 */ 4963 static int 4964 parse_libdir(const char *str) 4965 { 4966 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 4967 const char *orig; 4968 int fd; 4969 char c; 4970 4971 orig = str; 4972 fd = 0; 4973 for (c = *str; c != '\0'; c = *++str) { 4974 if (c < '0' || c > '9') 4975 return (-1); 4976 4977 fd *= RADIX; 4978 fd += c - '0'; 4979 } 4980 4981 /* Make sure we actually parsed something. */ 4982 if (str == orig) { 4983 _rtld_error("failed to parse directory FD from '%s'", str); 4984 return (-1); 4985 } 4986 return (fd); 4987 } 4988 4989 /* 4990 * Overrides for libc_pic-provided functions. 4991 */ 4992 4993 int 4994 __getosreldate(void) 4995 { 4996 size_t len; 4997 int oid[2]; 4998 int error, osrel; 4999 5000 if (osreldate != 0) 5001 return (osreldate); 5002 5003 oid[0] = CTL_KERN; 5004 oid[1] = KERN_OSRELDATE; 5005 osrel = 0; 5006 len = sizeof(osrel); 5007 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 5008 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 5009 osreldate = osrel; 5010 return (osreldate); 5011 } 5012 5013 void 5014 exit(int status) 5015 { 5016 5017 _exit(status); 5018 } 5019 5020 void (*__cleanup)(void); 5021 int __isthreaded = 0; 5022 int _thread_autoinit_dummy_decl = 1; 5023 5024 /* 5025 * No unresolved symbols for rtld. 5026 */ 5027 void 5028 __pthread_cxa_finalize(struct dl_phdr_info *a) 5029 { 5030 } 5031 5032 void 5033 __stack_chk_fail(void) 5034 { 5035 5036 _rtld_error("stack overflow detected; terminated"); 5037 die(); 5038 } 5039 __weak_reference(__stack_chk_fail, __stack_chk_fail_local); 5040 5041 void 5042 __chk_fail(void) 5043 { 5044 5045 _rtld_error("buffer overflow detected; terminated"); 5046 die(); 5047 } 5048 5049 const char * 5050 rtld_strerror(int errnum) 5051 { 5052 5053 if (errnum < 0 || errnum >= sys_nerr) 5054 return ("Unknown error"); 5055 return (sys_errlist[errnum]); 5056 } 5057