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 int plttype = DT_REL; 880 881 *dyn_rpath = NULL; 882 *dyn_soname = NULL; 883 *dyn_runpath = NULL; 884 885 obj->bind_now = false; 886 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 887 switch (dynp->d_tag) { 888 889 case DT_REL: 890 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 891 break; 892 893 case DT_RELSZ: 894 obj->relsize = dynp->d_un.d_val; 895 break; 896 897 case DT_RELENT: 898 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 899 break; 900 901 case DT_JMPREL: 902 obj->pltrel = (const Elf_Rel *) 903 (obj->relocbase + dynp->d_un.d_ptr); 904 break; 905 906 case DT_PLTRELSZ: 907 obj->pltrelsize = dynp->d_un.d_val; 908 break; 909 910 case DT_RELA: 911 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 912 break; 913 914 case DT_RELASZ: 915 obj->relasize = dynp->d_un.d_val; 916 break; 917 918 case DT_RELAENT: 919 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 920 break; 921 922 case DT_PLTREL: 923 plttype = dynp->d_un.d_val; 924 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 925 break; 926 927 case DT_SYMTAB: 928 obj->symtab = (const Elf_Sym *) 929 (obj->relocbase + dynp->d_un.d_ptr); 930 break; 931 932 case DT_SYMENT: 933 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 934 break; 935 936 case DT_STRTAB: 937 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 938 break; 939 940 case DT_STRSZ: 941 obj->strsize = dynp->d_un.d_val; 942 break; 943 944 case DT_VERNEED: 945 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 946 dynp->d_un.d_val); 947 break; 948 949 case DT_VERNEEDNUM: 950 obj->verneednum = dynp->d_un.d_val; 951 break; 952 953 case DT_VERDEF: 954 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 955 dynp->d_un.d_val); 956 break; 957 958 case DT_VERDEFNUM: 959 obj->verdefnum = dynp->d_un.d_val; 960 break; 961 962 case DT_VERSYM: 963 obj->versyms = (const Elf_Versym *)(obj->relocbase + 964 dynp->d_un.d_val); 965 break; 966 967 case DT_HASH: 968 { 969 hashtab = (const Elf_Hashelt *)(obj->relocbase + 970 dynp->d_un.d_ptr); 971 obj->nbuckets = hashtab[0]; 972 obj->nchains = hashtab[1]; 973 obj->buckets = hashtab + 2; 974 obj->chains = obj->buckets + obj->nbuckets; 975 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 976 obj->buckets != NULL; 977 } 978 break; 979 980 case DT_GNU_HASH: 981 { 982 hashtab = (const Elf_Hashelt *)(obj->relocbase + 983 dynp->d_un.d_ptr); 984 obj->nbuckets_gnu = hashtab[0]; 985 obj->symndx_gnu = hashtab[1]; 986 nmaskwords = hashtab[2]; 987 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 988 obj->maskwords_bm_gnu = nmaskwords - 1; 989 obj->shift2_gnu = hashtab[3]; 990 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4); 991 obj->buckets_gnu = hashtab + 4 + bloom_size32; 992 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 993 obj->symndx_gnu; 994 /* Number of bitmask words is required to be power of 2 */ 995 obj->valid_hash_gnu = powerof2(nmaskwords) && 996 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 997 } 998 break; 999 1000 case DT_NEEDED: 1001 if (!obj->rtld) { 1002 Needed_Entry *nep = NEW(Needed_Entry); 1003 nep->name = dynp->d_un.d_val; 1004 nep->obj = NULL; 1005 nep->next = NULL; 1006 1007 *needed_tail = nep; 1008 needed_tail = &nep->next; 1009 } 1010 break; 1011 1012 case DT_FILTER: 1013 if (!obj->rtld) { 1014 Needed_Entry *nep = NEW(Needed_Entry); 1015 nep->name = dynp->d_un.d_val; 1016 nep->obj = NULL; 1017 nep->next = NULL; 1018 1019 *needed_filtees_tail = nep; 1020 needed_filtees_tail = &nep->next; 1021 } 1022 break; 1023 1024 case DT_AUXILIARY: 1025 if (!obj->rtld) { 1026 Needed_Entry *nep = NEW(Needed_Entry); 1027 nep->name = dynp->d_un.d_val; 1028 nep->obj = NULL; 1029 nep->next = NULL; 1030 1031 *needed_aux_filtees_tail = nep; 1032 needed_aux_filtees_tail = &nep->next; 1033 } 1034 break; 1035 1036 case DT_PLTGOT: 1037 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 1038 break; 1039 1040 case DT_TEXTREL: 1041 obj->textrel = true; 1042 break; 1043 1044 case DT_SYMBOLIC: 1045 obj->symbolic = true; 1046 break; 1047 1048 case DT_RPATH: 1049 /* 1050 * We have to wait until later to process this, because we 1051 * might not have gotten the address of the string table yet. 1052 */ 1053 *dyn_rpath = dynp; 1054 break; 1055 1056 case DT_SONAME: 1057 *dyn_soname = dynp; 1058 break; 1059 1060 case DT_RUNPATH: 1061 *dyn_runpath = dynp; 1062 break; 1063 1064 case DT_INIT: 1065 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1066 break; 1067 1068 case DT_PREINIT_ARRAY: 1069 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1070 break; 1071 1072 case DT_PREINIT_ARRAYSZ: 1073 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1074 break; 1075 1076 case DT_INIT_ARRAY: 1077 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1078 break; 1079 1080 case DT_INIT_ARRAYSZ: 1081 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1082 break; 1083 1084 case DT_FINI: 1085 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1086 break; 1087 1088 case DT_FINI_ARRAY: 1089 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1090 break; 1091 1092 case DT_FINI_ARRAYSZ: 1093 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1094 break; 1095 1096 /* 1097 * Don't process DT_DEBUG on MIPS as the dynamic section 1098 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1099 */ 1100 1101 #ifndef __mips__ 1102 case DT_DEBUG: 1103 /* XXX - not implemented yet */ 1104 if (!early) 1105 dbg("Filling in DT_DEBUG entry"); 1106 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 1107 break; 1108 #endif 1109 1110 case DT_FLAGS: 1111 if ((dynp->d_un.d_val & DF_ORIGIN) && trust) 1112 obj->z_origin = true; 1113 if (dynp->d_un.d_val & DF_SYMBOLIC) 1114 obj->symbolic = true; 1115 if (dynp->d_un.d_val & DF_TEXTREL) 1116 obj->textrel = true; 1117 if (dynp->d_un.d_val & DF_BIND_NOW) 1118 obj->bind_now = true; 1119 /*if (dynp->d_un.d_val & DF_STATIC_TLS) 1120 ;*/ 1121 break; 1122 #ifdef __mips__ 1123 case DT_MIPS_LOCAL_GOTNO: 1124 obj->local_gotno = dynp->d_un.d_val; 1125 break; 1126 1127 case DT_MIPS_SYMTABNO: 1128 obj->symtabno = dynp->d_un.d_val; 1129 break; 1130 1131 case DT_MIPS_GOTSYM: 1132 obj->gotsym = dynp->d_un.d_val; 1133 break; 1134 1135 case DT_MIPS_RLD_MAP: 1136 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1137 break; 1138 #endif 1139 1140 case DT_FLAGS_1: 1141 if (dynp->d_un.d_val & DF_1_NOOPEN) 1142 obj->z_noopen = true; 1143 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust) 1144 obj->z_origin = true; 1145 /*if (dynp->d_un.d_val & DF_1_GLOBAL) 1146 XXX ;*/ 1147 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1148 obj->bind_now = true; 1149 if (dynp->d_un.d_val & DF_1_NODELETE) 1150 obj->z_nodelete = true; 1151 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1152 obj->z_loadfltr = true; 1153 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1154 obj->z_interpose = true; 1155 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1156 obj->z_nodeflib = true; 1157 break; 1158 1159 default: 1160 if (!early) { 1161 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1162 (long)dynp->d_tag); 1163 } 1164 break; 1165 } 1166 } 1167 1168 obj->traced = false; 1169 1170 if (plttype == DT_RELA) { 1171 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1172 obj->pltrel = NULL; 1173 obj->pltrelasize = obj->pltrelsize; 1174 obj->pltrelsize = 0; 1175 } 1176 1177 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1178 if (obj->valid_hash_sysv) 1179 obj->dynsymcount = obj->nchains; 1180 else if (obj->valid_hash_gnu) { 1181 obj->dynsymcount = 0; 1182 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1183 if (obj->buckets_gnu[bkt] == 0) 1184 continue; 1185 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1186 do 1187 obj->dynsymcount++; 1188 while ((*hashval++ & 1u) == 0); 1189 } 1190 obj->dynsymcount += obj->symndx_gnu; 1191 } 1192 } 1193 1194 static void 1195 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1196 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1197 { 1198 1199 if (obj->z_origin && obj->origin_path == NULL) { 1200 obj->origin_path = xmalloc(PATH_MAX); 1201 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1) 1202 die(); 1203 } 1204 1205 if (dyn_runpath != NULL) { 1206 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val; 1207 if (obj->z_origin) 1208 obj->runpath = origin_subst(obj->runpath, obj->origin_path); 1209 } 1210 else if (dyn_rpath != NULL) { 1211 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 1212 if (obj->z_origin) 1213 obj->rpath = origin_subst(obj->rpath, obj->origin_path); 1214 } 1215 1216 if (dyn_soname != NULL) 1217 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1218 } 1219 1220 static void 1221 digest_dynamic(Obj_Entry *obj, int early) 1222 { 1223 const Elf_Dyn *dyn_rpath; 1224 const Elf_Dyn *dyn_soname; 1225 const Elf_Dyn *dyn_runpath; 1226 1227 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1228 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath); 1229 } 1230 1231 /* 1232 * Process a shared object's program header. This is used only for the 1233 * main program, when the kernel has already loaded the main program 1234 * into memory before calling the dynamic linker. It creates and 1235 * returns an Obj_Entry structure. 1236 */ 1237 static Obj_Entry * 1238 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1239 { 1240 Obj_Entry *obj; 1241 const Elf_Phdr *phlimit = phdr + phnum; 1242 const Elf_Phdr *ph; 1243 Elf_Addr note_start, note_end; 1244 int nsegs = 0; 1245 1246 obj = obj_new(); 1247 for (ph = phdr; ph < phlimit; ph++) { 1248 if (ph->p_type != PT_PHDR) 1249 continue; 1250 1251 obj->phdr = phdr; 1252 obj->phsize = ph->p_memsz; 1253 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1254 break; 1255 } 1256 1257 obj->stack_flags = PF_X | PF_R | PF_W; 1258 1259 for (ph = phdr; ph < phlimit; ph++) { 1260 switch (ph->p_type) { 1261 1262 case PT_INTERP: 1263 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1264 break; 1265 1266 case PT_LOAD: 1267 if (nsegs == 0) { /* First load segment */ 1268 obj->vaddrbase = trunc_page(ph->p_vaddr); 1269 obj->mapbase = obj->vaddrbase + obj->relocbase; 1270 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1271 obj->vaddrbase; 1272 } else { /* Last load segment */ 1273 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1274 obj->vaddrbase; 1275 } 1276 nsegs++; 1277 break; 1278 1279 case PT_DYNAMIC: 1280 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1281 break; 1282 1283 case PT_TLS: 1284 obj->tlsindex = 1; 1285 obj->tlssize = ph->p_memsz; 1286 obj->tlsalign = ph->p_align; 1287 obj->tlsinitsize = ph->p_filesz; 1288 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1289 break; 1290 1291 case PT_GNU_STACK: 1292 obj->stack_flags = ph->p_flags; 1293 break; 1294 1295 case PT_GNU_RELRO: 1296 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1297 obj->relro_size = round_page(ph->p_memsz); 1298 break; 1299 1300 case PT_NOTE: 1301 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1302 note_end = note_start + ph->p_filesz; 1303 digest_notes(obj, note_start, note_end); 1304 break; 1305 } 1306 } 1307 if (nsegs < 1) { 1308 _rtld_error("%s: too few PT_LOAD segments", path); 1309 return NULL; 1310 } 1311 1312 obj->entry = entry; 1313 return obj; 1314 } 1315 1316 void 1317 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1318 { 1319 const Elf_Note *note; 1320 const char *note_name; 1321 uintptr_t p; 1322 1323 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1324 note = (const Elf_Note *)((const char *)(note + 1) + 1325 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1326 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1327 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1328 note->n_descsz != sizeof(int32_t)) 1329 continue; 1330 if (note->n_type != ABI_NOTETYPE && 1331 note->n_type != CRT_NOINIT_NOTETYPE) 1332 continue; 1333 note_name = (const char *)(note + 1); 1334 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1335 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1336 continue; 1337 switch (note->n_type) { 1338 case ABI_NOTETYPE: 1339 /* FreeBSD osrel note */ 1340 p = (uintptr_t)(note + 1); 1341 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1342 obj->osrel = *(const int32_t *)(p); 1343 dbg("note osrel %d", obj->osrel); 1344 break; 1345 case CRT_NOINIT_NOTETYPE: 1346 /* FreeBSD 'crt does not call init' note */ 1347 obj->crt_no_init = true; 1348 dbg("note crt_no_init"); 1349 break; 1350 } 1351 } 1352 } 1353 1354 static Obj_Entry * 1355 dlcheck(void *handle) 1356 { 1357 Obj_Entry *obj; 1358 1359 for (obj = obj_list; obj != NULL; obj = obj->next) 1360 if (obj == (Obj_Entry *) handle) 1361 break; 1362 1363 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1364 _rtld_error("Invalid shared object handle %p", handle); 1365 return NULL; 1366 } 1367 return obj; 1368 } 1369 1370 /* 1371 * If the given object is already in the donelist, return true. Otherwise 1372 * add the object to the list and return false. 1373 */ 1374 static bool 1375 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1376 { 1377 unsigned int i; 1378 1379 for (i = 0; i < dlp->num_used; i++) 1380 if (dlp->objs[i] == obj) 1381 return true; 1382 /* 1383 * Our donelist allocation should always be sufficient. But if 1384 * our threads locking isn't working properly, more shared objects 1385 * could have been loaded since we allocated the list. That should 1386 * never happen, but we'll handle it properly just in case it does. 1387 */ 1388 if (dlp->num_used < dlp->num_alloc) 1389 dlp->objs[dlp->num_used++] = obj; 1390 return false; 1391 } 1392 1393 /* 1394 * Hash function for symbol table lookup. Don't even think about changing 1395 * this. It is specified by the System V ABI. 1396 */ 1397 unsigned long 1398 elf_hash(const char *name) 1399 { 1400 const unsigned char *p = (const unsigned char *) name; 1401 unsigned long h = 0; 1402 unsigned long g; 1403 1404 while (*p != '\0') { 1405 h = (h << 4) + *p++; 1406 if ((g = h & 0xf0000000) != 0) 1407 h ^= g >> 24; 1408 h &= ~g; 1409 } 1410 return h; 1411 } 1412 1413 /* 1414 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1415 * unsigned in case it's implemented with a wider type. 1416 */ 1417 static uint32_t 1418 gnu_hash(const char *s) 1419 { 1420 uint32_t h; 1421 unsigned char c; 1422 1423 h = 5381; 1424 for (c = *s; c != '\0'; c = *++s) 1425 h = h * 33 + c; 1426 return (h & 0xffffffff); 1427 } 1428 1429 1430 /* 1431 * Find the library with the given name, and return its full pathname. 1432 * The returned string is dynamically allocated. Generates an error 1433 * message and returns NULL if the library cannot be found. 1434 * 1435 * If the second argument is non-NULL, then it refers to an already- 1436 * loaded shared object, whose library search path will be searched. 1437 * 1438 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1439 * descriptor (which is close-on-exec) will be passed out via the third 1440 * argument. 1441 * 1442 * The search order is: 1443 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1444 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1445 * LD_LIBRARY_PATH 1446 * DT_RUNPATH in the referencing file 1447 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1448 * from list) 1449 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1450 * 1451 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1452 */ 1453 static char * 1454 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1455 { 1456 char *pathname; 1457 char *name; 1458 bool nodeflib, objgiven; 1459 1460 objgiven = refobj != NULL; 1461 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */ 1462 if (xname[0] != '/' && !trust) { 1463 _rtld_error("Absolute pathname required for shared object \"%s\"", 1464 xname); 1465 return NULL; 1466 } 1467 if (objgiven && refobj->z_origin) { 1468 return (origin_subst(__DECONST(char *, xname), 1469 refobj->origin_path)); 1470 } else { 1471 return (xstrdup(xname)); 1472 } 1473 } 1474 1475 if (libmap_disable || !objgiven || 1476 (name = lm_find(refobj->path, xname)) == NULL) 1477 name = (char *)xname; 1478 1479 dbg(" Searching for \"%s\"", name); 1480 1481 /* 1482 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1483 * back to pre-conforming behaviour if user requested so with 1484 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1485 * nodeflib. 1486 */ 1487 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1488 if ((pathname = search_library_path(name, ld_library_path)) != NULL || 1489 (refobj != NULL && 1490 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1491 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL || 1492 (pathname = search_library_path(name, gethints(false))) != NULL || 1493 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL) 1494 return (pathname); 1495 } else { 1496 nodeflib = objgiven ? refobj->z_nodeflib : false; 1497 if ((objgiven && 1498 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1499 (objgiven && refobj->runpath == NULL && refobj != obj_main && 1500 (pathname = search_library_path(name, obj_main->rpath)) != NULL) || 1501 (pathname = search_library_path(name, ld_library_path)) != NULL || 1502 (objgiven && 1503 (pathname = search_library_path(name, refobj->runpath)) != NULL) || 1504 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL || 1505 (pathname = search_library_path(name, gethints(nodeflib))) != NULL || 1506 (objgiven && !nodeflib && 1507 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)) 1508 return (pathname); 1509 } 1510 1511 if (objgiven && refobj->path != NULL) { 1512 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 1513 name, basename(refobj->path)); 1514 } else { 1515 _rtld_error("Shared object \"%s\" not found", name); 1516 } 1517 return NULL; 1518 } 1519 1520 /* 1521 * Given a symbol number in a referencing object, find the corresponding 1522 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1523 * no definition was found. Returns a pointer to the Obj_Entry of the 1524 * defining object via the reference parameter DEFOBJ_OUT. 1525 */ 1526 const Elf_Sym * 1527 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1528 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1529 RtldLockState *lockstate) 1530 { 1531 const Elf_Sym *ref; 1532 const Elf_Sym *def; 1533 const Obj_Entry *defobj; 1534 SymLook req; 1535 const char *name; 1536 int res; 1537 1538 /* 1539 * If we have already found this symbol, get the information from 1540 * the cache. 1541 */ 1542 if (symnum >= refobj->dynsymcount) 1543 return NULL; /* Bad object */ 1544 if (cache != NULL && cache[symnum].sym != NULL) { 1545 *defobj_out = cache[symnum].obj; 1546 return cache[symnum].sym; 1547 } 1548 1549 ref = refobj->symtab + symnum; 1550 name = refobj->strtab + ref->st_name; 1551 def = NULL; 1552 defobj = NULL; 1553 1554 /* 1555 * We don't have to do a full scale lookup if the symbol is local. 1556 * We know it will bind to the instance in this load module; to 1557 * which we already have a pointer (ie ref). By not doing a lookup, 1558 * we not only improve performance, but it also avoids unresolvable 1559 * symbols when local symbols are not in the hash table. This has 1560 * been seen with the ia64 toolchain. 1561 */ 1562 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1563 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1564 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1565 symnum); 1566 } 1567 symlook_init(&req, name); 1568 req.flags = flags; 1569 req.ventry = fetch_ventry(refobj, symnum); 1570 req.lockstate = lockstate; 1571 res = symlook_default(&req, refobj); 1572 if (res == 0) { 1573 def = req.sym_out; 1574 defobj = req.defobj_out; 1575 } 1576 } else { 1577 def = ref; 1578 defobj = refobj; 1579 } 1580 1581 /* 1582 * If we found no definition and the reference is weak, treat the 1583 * symbol as having the value zero. 1584 */ 1585 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1586 def = &sym_zero; 1587 defobj = obj_main; 1588 } 1589 1590 if (def != NULL) { 1591 *defobj_out = defobj; 1592 /* Record the information in the cache to avoid subsequent lookups. */ 1593 if (cache != NULL) { 1594 cache[symnum].sym = def; 1595 cache[symnum].obj = defobj; 1596 } 1597 } else { 1598 if (refobj != &obj_rtld) 1599 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name); 1600 } 1601 return def; 1602 } 1603 1604 /* 1605 * Return the search path from the ldconfig hints file, reading it if 1606 * necessary. If nostdlib is true, then the default search paths are 1607 * not added to result. 1608 * 1609 * Returns NULL if there are problems with the hints file, 1610 * or if the search path there is empty. 1611 */ 1612 static const char * 1613 gethints(bool nostdlib) 1614 { 1615 static char *hints, *filtered_path; 1616 struct elfhints_hdr hdr; 1617 struct fill_search_info_args sargs, hargs; 1618 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1619 struct dl_serpath *SLPpath, *hintpath; 1620 char *p; 1621 unsigned int SLPndx, hintndx, fndx, fcount; 1622 int fd; 1623 size_t flen; 1624 bool skip; 1625 1626 /* First call, read the hints file */ 1627 if (hints == NULL) { 1628 /* Keep from trying again in case the hints file is bad. */ 1629 hints = ""; 1630 1631 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1632 return (NULL); 1633 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1634 hdr.magic != ELFHINTS_MAGIC || 1635 hdr.version != 1) { 1636 close(fd); 1637 return (NULL); 1638 } 1639 p = xmalloc(hdr.dirlistlen + 1); 1640 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1641 read(fd, p, hdr.dirlistlen + 1) != 1642 (ssize_t)hdr.dirlistlen + 1) { 1643 free(p); 1644 close(fd); 1645 return (NULL); 1646 } 1647 hints = p; 1648 close(fd); 1649 } 1650 1651 /* 1652 * If caller agreed to receive list which includes the default 1653 * paths, we are done. Otherwise, if we still did not 1654 * calculated filtered result, do it now. 1655 */ 1656 if (!nostdlib) 1657 return (hints[0] != '\0' ? hints : NULL); 1658 if (filtered_path != NULL) 1659 goto filt_ret; 1660 1661 /* 1662 * Obtain the list of all configured search paths, and the 1663 * list of the default paths. 1664 * 1665 * First estimate the size of the results. 1666 */ 1667 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1668 smeta.dls_cnt = 0; 1669 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1670 hmeta.dls_cnt = 0; 1671 1672 sargs.request = RTLD_DI_SERINFOSIZE; 1673 sargs.serinfo = &smeta; 1674 hargs.request = RTLD_DI_SERINFOSIZE; 1675 hargs.serinfo = &hmeta; 1676 1677 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1678 path_enumerate(p, fill_search_info, &hargs); 1679 1680 SLPinfo = xmalloc(smeta.dls_size); 1681 hintinfo = xmalloc(hmeta.dls_size); 1682 1683 /* 1684 * Next fetch both sets of paths. 1685 */ 1686 sargs.request = RTLD_DI_SERINFO; 1687 sargs.serinfo = SLPinfo; 1688 sargs.serpath = &SLPinfo->dls_serpath[0]; 1689 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1690 1691 hargs.request = RTLD_DI_SERINFO; 1692 hargs.serinfo = hintinfo; 1693 hargs.serpath = &hintinfo->dls_serpath[0]; 1694 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1695 1696 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1697 path_enumerate(p, fill_search_info, &hargs); 1698 1699 /* 1700 * Now calculate the difference between two sets, by excluding 1701 * standard paths from the full set. 1702 */ 1703 fndx = 0; 1704 fcount = 0; 1705 filtered_path = xmalloc(hdr.dirlistlen + 1); 1706 hintpath = &hintinfo->dls_serpath[0]; 1707 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1708 skip = false; 1709 SLPpath = &SLPinfo->dls_serpath[0]; 1710 /* 1711 * Check each standard path against current. 1712 */ 1713 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1714 /* matched, skip the path */ 1715 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1716 skip = true; 1717 break; 1718 } 1719 } 1720 if (skip) 1721 continue; 1722 /* 1723 * Not matched against any standard path, add the path 1724 * to result. Separate consequtive paths with ':'. 1725 */ 1726 if (fcount > 0) { 1727 filtered_path[fndx] = ':'; 1728 fndx++; 1729 } 1730 fcount++; 1731 flen = strlen(hintpath->dls_name); 1732 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1733 fndx += flen; 1734 } 1735 filtered_path[fndx] = '\0'; 1736 1737 free(SLPinfo); 1738 free(hintinfo); 1739 1740 filt_ret: 1741 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1742 } 1743 1744 static void 1745 init_dag(Obj_Entry *root) 1746 { 1747 const Needed_Entry *needed; 1748 const Objlist_Entry *elm; 1749 DoneList donelist; 1750 1751 if (root->dag_inited) 1752 return; 1753 donelist_init(&donelist); 1754 1755 /* Root object belongs to own DAG. */ 1756 objlist_push_tail(&root->dldags, root); 1757 objlist_push_tail(&root->dagmembers, root); 1758 donelist_check(&donelist, root); 1759 1760 /* 1761 * Add dependencies of root object to DAG in breadth order 1762 * by exploiting the fact that each new object get added 1763 * to the tail of the dagmembers list. 1764 */ 1765 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1766 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1767 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1768 continue; 1769 objlist_push_tail(&needed->obj->dldags, root); 1770 objlist_push_tail(&root->dagmembers, needed->obj); 1771 } 1772 } 1773 root->dag_inited = true; 1774 } 1775 1776 static void 1777 process_nodelete(Obj_Entry *root) 1778 { 1779 const Objlist_Entry *elm; 1780 1781 /* 1782 * Walk over object DAG and process every dependent object that 1783 * is marked as DF_1_NODELETE. They need to grow their own DAG, 1784 * which then should have its reference upped separately. 1785 */ 1786 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1787 if (elm->obj != NULL && elm->obj->z_nodelete && 1788 !elm->obj->ref_nodel) { 1789 dbg("obj %s nodelete", elm->obj->path); 1790 init_dag(elm->obj); 1791 ref_dag(elm->obj); 1792 elm->obj->ref_nodel = true; 1793 } 1794 } 1795 } 1796 /* 1797 * Initialize the dynamic linker. The argument is the address at which 1798 * the dynamic linker has been mapped into memory. The primary task of 1799 * this function is to relocate the dynamic linker. 1800 */ 1801 static void 1802 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 1803 { 1804 Obj_Entry objtmp; /* Temporary rtld object */ 1805 const Elf_Dyn *dyn_rpath; 1806 const Elf_Dyn *dyn_soname; 1807 const Elf_Dyn *dyn_runpath; 1808 1809 #ifdef RTLD_INIT_PAGESIZES_EARLY 1810 /* The page size is required by the dynamic memory allocator. */ 1811 init_pagesizes(aux_info); 1812 #endif 1813 1814 /* 1815 * Conjure up an Obj_Entry structure for the dynamic linker. 1816 * 1817 * The "path" member can't be initialized yet because string constants 1818 * cannot yet be accessed. Below we will set it correctly. 1819 */ 1820 memset(&objtmp, 0, sizeof(objtmp)); 1821 objtmp.path = NULL; 1822 objtmp.rtld = true; 1823 objtmp.mapbase = mapbase; 1824 #ifdef PIC 1825 objtmp.relocbase = mapbase; 1826 #endif 1827 if (RTLD_IS_DYNAMIC()) { 1828 objtmp.dynamic = rtld_dynamic(&objtmp); 1829 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 1830 assert(objtmp.needed == NULL); 1831 #if !defined(__mips__) 1832 /* MIPS has a bogus DT_TEXTREL. */ 1833 assert(!objtmp.textrel); 1834 #endif 1835 1836 /* 1837 * Temporarily put the dynamic linker entry into the object list, so 1838 * that symbols can be found. 1839 */ 1840 1841 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 1842 } 1843 1844 /* Initialize the object list. */ 1845 obj_tail = &obj_list; 1846 1847 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1848 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1849 1850 #ifndef RTLD_INIT_PAGESIZES_EARLY 1851 /* The page size is required by the dynamic memory allocator. */ 1852 init_pagesizes(aux_info); 1853 #endif 1854 1855 if (aux_info[AT_OSRELDATE] != NULL) 1856 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 1857 1858 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 1859 1860 /* Replace the path with a dynamically allocated copy. */ 1861 obj_rtld.path = xstrdup(PATH_RTLD); 1862 1863 r_debug.r_brk = r_debug_state; 1864 r_debug.r_state = RT_CONSISTENT; 1865 } 1866 1867 /* 1868 * Retrieve the array of supported page sizes. The kernel provides the page 1869 * sizes in increasing order. 1870 */ 1871 static void 1872 init_pagesizes(Elf_Auxinfo **aux_info) 1873 { 1874 static size_t psa[MAXPAGESIZES]; 1875 int mib[2]; 1876 size_t len, size; 1877 1878 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 1879 NULL) { 1880 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 1881 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 1882 } else { 1883 len = 2; 1884 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 1885 size = sizeof(psa); 1886 else { 1887 /* As a fallback, retrieve the base page size. */ 1888 size = sizeof(psa[0]); 1889 if (aux_info[AT_PAGESZ] != NULL) { 1890 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 1891 goto psa_filled; 1892 } else { 1893 mib[0] = CTL_HW; 1894 mib[1] = HW_PAGESIZE; 1895 len = 2; 1896 } 1897 } 1898 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 1899 _rtld_error("sysctl for hw.pagesize(s) failed"); 1900 die(); 1901 } 1902 psa_filled: 1903 pagesizes = psa; 1904 } 1905 npagesizes = size / sizeof(pagesizes[0]); 1906 /* Discard any invalid entries at the end of the array. */ 1907 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 1908 npagesizes--; 1909 } 1910 1911 /* 1912 * Add the init functions from a needed object list (and its recursive 1913 * needed objects) to "list". This is not used directly; it is a helper 1914 * function for initlist_add_objects(). The write lock must be held 1915 * when this function is called. 1916 */ 1917 static void 1918 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 1919 { 1920 /* Recursively process the successor needed objects. */ 1921 if (needed->next != NULL) 1922 initlist_add_neededs(needed->next, list); 1923 1924 /* Process the current needed object. */ 1925 if (needed->obj != NULL) 1926 initlist_add_objects(needed->obj, &needed->obj->next, list); 1927 } 1928 1929 /* 1930 * Scan all of the DAGs rooted in the range of objects from "obj" to 1931 * "tail" and add their init functions to "list". This recurses over 1932 * the DAGs and ensure the proper init ordering such that each object's 1933 * needed libraries are initialized before the object itself. At the 1934 * same time, this function adds the objects to the global finalization 1935 * list "list_fini" in the opposite order. The write lock must be 1936 * held when this function is called. 1937 */ 1938 static void 1939 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list) 1940 { 1941 1942 if (obj->init_scanned || obj->init_done) 1943 return; 1944 obj->init_scanned = true; 1945 1946 /* Recursively process the successor objects. */ 1947 if (&obj->next != tail) 1948 initlist_add_objects(obj->next, tail, list); 1949 1950 /* Recursively process the needed objects. */ 1951 if (obj->needed != NULL) 1952 initlist_add_neededs(obj->needed, list); 1953 if (obj->needed_filtees != NULL) 1954 initlist_add_neededs(obj->needed_filtees, list); 1955 if (obj->needed_aux_filtees != NULL) 1956 initlist_add_neededs(obj->needed_aux_filtees, list); 1957 1958 /* Add the object to the init list. */ 1959 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL || 1960 obj->init_array != (Elf_Addr)NULL) 1961 objlist_push_tail(list, obj); 1962 1963 /* Add the object to the global fini list in the reverse order. */ 1964 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 1965 && !obj->on_fini_list) { 1966 objlist_push_head(&list_fini, obj); 1967 obj->on_fini_list = true; 1968 } 1969 } 1970 1971 #ifndef FPTR_TARGET 1972 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 1973 #endif 1974 1975 static void 1976 free_needed_filtees(Needed_Entry *n) 1977 { 1978 Needed_Entry *needed, *needed1; 1979 1980 for (needed = n; needed != NULL; needed = needed->next) { 1981 if (needed->obj != NULL) { 1982 dlclose(needed->obj); 1983 needed->obj = NULL; 1984 } 1985 } 1986 for (needed = n; needed != NULL; needed = needed1) { 1987 needed1 = needed->next; 1988 free(needed); 1989 } 1990 } 1991 1992 static void 1993 unload_filtees(Obj_Entry *obj) 1994 { 1995 1996 free_needed_filtees(obj->needed_filtees); 1997 obj->needed_filtees = NULL; 1998 free_needed_filtees(obj->needed_aux_filtees); 1999 obj->needed_aux_filtees = NULL; 2000 obj->filtees_loaded = false; 2001 } 2002 2003 static void 2004 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2005 RtldLockState *lockstate) 2006 { 2007 2008 for (; needed != NULL; needed = needed->next) { 2009 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2010 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2011 RTLD_LOCAL, lockstate); 2012 } 2013 } 2014 2015 static void 2016 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2017 { 2018 2019 lock_restart_for_upgrade(lockstate); 2020 if (!obj->filtees_loaded) { 2021 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2022 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2023 obj->filtees_loaded = true; 2024 } 2025 } 2026 2027 static int 2028 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2029 { 2030 Obj_Entry *obj1; 2031 2032 for (; needed != NULL; needed = needed->next) { 2033 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2034 flags & ~RTLD_LO_NOLOAD); 2035 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2036 return (-1); 2037 } 2038 return (0); 2039 } 2040 2041 /* 2042 * Given a shared object, traverse its list of needed objects, and load 2043 * each of them. Returns 0 on success. Generates an error message and 2044 * returns -1 on failure. 2045 */ 2046 static int 2047 load_needed_objects(Obj_Entry *first, int flags) 2048 { 2049 Obj_Entry *obj; 2050 2051 for (obj = first; obj != NULL; obj = obj->next) { 2052 if (process_needed(obj, obj->needed, flags) == -1) 2053 return (-1); 2054 } 2055 return (0); 2056 } 2057 2058 static int 2059 load_preload_objects(void) 2060 { 2061 char *p = ld_preload; 2062 Obj_Entry *obj; 2063 static const char delim[] = " \t:;"; 2064 2065 if (p == NULL) 2066 return 0; 2067 2068 p += strspn(p, delim); 2069 while (*p != '\0') { 2070 size_t len = strcspn(p, delim); 2071 char savech; 2072 2073 savech = p[len]; 2074 p[len] = '\0'; 2075 obj = load_object(p, -1, NULL, 0); 2076 if (obj == NULL) 2077 return -1; /* XXX - cleanup */ 2078 obj->z_interpose = true; 2079 p[len] = savech; 2080 p += len; 2081 p += strspn(p, delim); 2082 } 2083 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2084 return 0; 2085 } 2086 2087 static const char * 2088 printable_path(const char *path) 2089 { 2090 2091 return (path == NULL ? "<unknown>" : path); 2092 } 2093 2094 /* 2095 * Load a shared object into memory, if it is not already loaded. The 2096 * object may be specified by name or by user-supplied file descriptor 2097 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2098 * duplicate is. 2099 * 2100 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2101 * on failure. 2102 */ 2103 static Obj_Entry * 2104 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2105 { 2106 Obj_Entry *obj; 2107 int fd; 2108 struct stat sb; 2109 char *path; 2110 2111 fd = -1; 2112 if (name != NULL) { 2113 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 2114 if (object_match_name(obj, name)) 2115 return (obj); 2116 } 2117 2118 path = find_library(name, refobj, &fd); 2119 if (path == NULL) 2120 return (NULL); 2121 } else 2122 path = NULL; 2123 2124 if (fd >= 0) { 2125 /* 2126 * search_library_pathfds() opens a fresh file descriptor for the 2127 * library, so there is no need to dup(). 2128 */ 2129 } else if (fd_u == -1) { 2130 /* 2131 * If we didn't find a match by pathname, or the name is not 2132 * supplied, open the file and check again by device and inode. 2133 * This avoids false mismatches caused by multiple links or ".." 2134 * in pathnames. 2135 * 2136 * To avoid a race, we open the file and use fstat() rather than 2137 * using stat(). 2138 */ 2139 if ((fd = open(path, O_RDONLY | O_CLOEXEC)) == -1) { 2140 _rtld_error("Cannot open \"%s\"", path); 2141 free(path); 2142 return (NULL); 2143 } 2144 } else { 2145 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2146 if (fd == -1) { 2147 _rtld_error("Cannot dup fd"); 2148 free(path); 2149 return (NULL); 2150 } 2151 } 2152 if (fstat(fd, &sb) == -1) { 2153 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2154 close(fd); 2155 free(path); 2156 return NULL; 2157 } 2158 for (obj = obj_list->next; obj != NULL; obj = obj->next) 2159 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2160 break; 2161 if (obj != NULL && name != NULL) { 2162 object_add_name(obj, name); 2163 free(path); 2164 close(fd); 2165 return obj; 2166 } 2167 if (flags & RTLD_LO_NOLOAD) { 2168 free(path); 2169 close(fd); 2170 return (NULL); 2171 } 2172 2173 /* First use of this object, so we must map it in */ 2174 obj = do_load_object(fd, name, path, &sb, flags); 2175 if (obj == NULL) 2176 free(path); 2177 close(fd); 2178 2179 return obj; 2180 } 2181 2182 static Obj_Entry * 2183 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2184 int flags) 2185 { 2186 Obj_Entry *obj; 2187 struct statfs fs; 2188 2189 /* 2190 * but first, make sure that environment variables haven't been 2191 * used to circumvent the noexec flag on a filesystem. 2192 */ 2193 if (dangerous_ld_env) { 2194 if (fstatfs(fd, &fs) != 0) { 2195 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2196 return NULL; 2197 } 2198 if (fs.f_flags & MNT_NOEXEC) { 2199 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 2200 return NULL; 2201 } 2202 } 2203 dbg("loading \"%s\"", printable_path(path)); 2204 obj = map_object(fd, printable_path(path), sbp); 2205 if (obj == NULL) 2206 return NULL; 2207 2208 /* 2209 * If DT_SONAME is present in the object, digest_dynamic2 already 2210 * added it to the object names. 2211 */ 2212 if (name != NULL) 2213 object_add_name(obj, name); 2214 obj->path = path; 2215 digest_dynamic(obj, 0); 2216 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2217 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2218 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2219 RTLD_LO_DLOPEN) { 2220 dbg("refusing to load non-loadable \"%s\"", obj->path); 2221 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2222 munmap(obj->mapbase, obj->mapsize); 2223 obj_free(obj); 2224 return (NULL); 2225 } 2226 2227 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2228 *obj_tail = obj; 2229 obj_tail = &obj->next; 2230 obj_count++; 2231 obj_loads++; 2232 linkmap_add(obj); /* for GDB & dlinfo() */ 2233 max_stack_flags |= obj->stack_flags; 2234 2235 dbg(" %p .. %p: %s", obj->mapbase, 2236 obj->mapbase + obj->mapsize - 1, obj->path); 2237 if (obj->textrel) 2238 dbg(" WARNING: %s has impure text", obj->path); 2239 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2240 obj->path); 2241 2242 return obj; 2243 } 2244 2245 static Obj_Entry * 2246 obj_from_addr(const void *addr) 2247 { 2248 Obj_Entry *obj; 2249 2250 for (obj = obj_list; obj != NULL; obj = obj->next) { 2251 if (addr < (void *) obj->mapbase) 2252 continue; 2253 if (addr < (void *) (obj->mapbase + obj->mapsize)) 2254 return obj; 2255 } 2256 return NULL; 2257 } 2258 2259 static void 2260 preinit_main(void) 2261 { 2262 Elf_Addr *preinit_addr; 2263 int index; 2264 2265 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2266 if (preinit_addr == NULL) 2267 return; 2268 2269 for (index = 0; index < obj_main->preinit_array_num; index++) { 2270 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2271 dbg("calling preinit function for %s at %p", obj_main->path, 2272 (void *)preinit_addr[index]); 2273 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2274 0, 0, obj_main->path); 2275 call_init_pointer(obj_main, preinit_addr[index]); 2276 } 2277 } 2278 } 2279 2280 /* 2281 * Call the finalization functions for each of the objects in "list" 2282 * belonging to the DAG of "root" and referenced once. If NULL "root" 2283 * is specified, every finalization function will be called regardless 2284 * of the reference count and the list elements won't be freed. All of 2285 * the objects are expected to have non-NULL fini functions. 2286 */ 2287 static void 2288 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2289 { 2290 Objlist_Entry *elm; 2291 char *saved_msg; 2292 Elf_Addr *fini_addr; 2293 int index; 2294 2295 assert(root == NULL || root->refcount == 1); 2296 2297 /* 2298 * Preserve the current error message since a fini function might 2299 * call into the dynamic linker and overwrite it. 2300 */ 2301 saved_msg = errmsg_save(); 2302 do { 2303 STAILQ_FOREACH(elm, list, link) { 2304 if (root != NULL && (elm->obj->refcount != 1 || 2305 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2306 continue; 2307 /* Remove object from fini list to prevent recursive invocation. */ 2308 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2309 /* 2310 * XXX: If a dlopen() call references an object while the 2311 * fini function is in progress, we might end up trying to 2312 * unload the referenced object in dlclose() or the object 2313 * won't be unloaded although its fini function has been 2314 * called. 2315 */ 2316 lock_release(rtld_bind_lock, lockstate); 2317 2318 /* 2319 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2320 * When this happens, DT_FINI_ARRAY is processed first. 2321 */ 2322 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2323 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2324 for (index = elm->obj->fini_array_num - 1; index >= 0; 2325 index--) { 2326 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2327 dbg("calling fini function for %s at %p", 2328 elm->obj->path, (void *)fini_addr[index]); 2329 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2330 (void *)fini_addr[index], 0, 0, elm->obj->path); 2331 call_initfini_pointer(elm->obj, fini_addr[index]); 2332 } 2333 } 2334 } 2335 if (elm->obj->fini != (Elf_Addr)NULL) { 2336 dbg("calling fini function for %s at %p", elm->obj->path, 2337 (void *)elm->obj->fini); 2338 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2339 0, 0, elm->obj->path); 2340 call_initfini_pointer(elm->obj, elm->obj->fini); 2341 } 2342 wlock_acquire(rtld_bind_lock, lockstate); 2343 /* No need to free anything if process is going down. */ 2344 if (root != NULL) 2345 free(elm); 2346 /* 2347 * We must restart the list traversal after every fini call 2348 * because a dlclose() call from the fini function or from 2349 * another thread might have modified the reference counts. 2350 */ 2351 break; 2352 } 2353 } while (elm != NULL); 2354 errmsg_restore(saved_msg); 2355 } 2356 2357 /* 2358 * Call the initialization functions for each of the objects in 2359 * "list". All of the objects are expected to have non-NULL init 2360 * functions. 2361 */ 2362 static void 2363 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2364 { 2365 Objlist_Entry *elm; 2366 Obj_Entry *obj; 2367 char *saved_msg; 2368 Elf_Addr *init_addr; 2369 int index; 2370 2371 /* 2372 * Clean init_scanned flag so that objects can be rechecked and 2373 * possibly initialized earlier if any of vectors called below 2374 * cause the change by using dlopen. 2375 */ 2376 for (obj = obj_list; obj != NULL; obj = obj->next) 2377 obj->init_scanned = false; 2378 2379 /* 2380 * Preserve the current error message since an init function might 2381 * call into the dynamic linker and overwrite it. 2382 */ 2383 saved_msg = errmsg_save(); 2384 STAILQ_FOREACH(elm, list, link) { 2385 if (elm->obj->init_done) /* Initialized early. */ 2386 continue; 2387 /* 2388 * Race: other thread might try to use this object before current 2389 * one completes the initilization. Not much can be done here 2390 * without better locking. 2391 */ 2392 elm->obj->init_done = true; 2393 lock_release(rtld_bind_lock, lockstate); 2394 2395 /* 2396 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2397 * When this happens, DT_INIT is processed first. 2398 */ 2399 if (elm->obj->init != (Elf_Addr)NULL) { 2400 dbg("calling init function for %s at %p", elm->obj->path, 2401 (void *)elm->obj->init); 2402 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2403 0, 0, elm->obj->path); 2404 call_initfini_pointer(elm->obj, elm->obj->init); 2405 } 2406 init_addr = (Elf_Addr *)elm->obj->init_array; 2407 if (init_addr != NULL) { 2408 for (index = 0; index < elm->obj->init_array_num; index++) { 2409 if (init_addr[index] != 0 && init_addr[index] != 1) { 2410 dbg("calling init function for %s at %p", elm->obj->path, 2411 (void *)init_addr[index]); 2412 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2413 (void *)init_addr[index], 0, 0, elm->obj->path); 2414 call_init_pointer(elm->obj, init_addr[index]); 2415 } 2416 } 2417 } 2418 wlock_acquire(rtld_bind_lock, lockstate); 2419 } 2420 errmsg_restore(saved_msg); 2421 } 2422 2423 static void 2424 objlist_clear(Objlist *list) 2425 { 2426 Objlist_Entry *elm; 2427 2428 while (!STAILQ_EMPTY(list)) { 2429 elm = STAILQ_FIRST(list); 2430 STAILQ_REMOVE_HEAD(list, link); 2431 free(elm); 2432 } 2433 } 2434 2435 static Objlist_Entry * 2436 objlist_find(Objlist *list, const Obj_Entry *obj) 2437 { 2438 Objlist_Entry *elm; 2439 2440 STAILQ_FOREACH(elm, list, link) 2441 if (elm->obj == obj) 2442 return elm; 2443 return NULL; 2444 } 2445 2446 static void 2447 objlist_init(Objlist *list) 2448 { 2449 STAILQ_INIT(list); 2450 } 2451 2452 static void 2453 objlist_push_head(Objlist *list, Obj_Entry *obj) 2454 { 2455 Objlist_Entry *elm; 2456 2457 elm = NEW(Objlist_Entry); 2458 elm->obj = obj; 2459 STAILQ_INSERT_HEAD(list, elm, link); 2460 } 2461 2462 static void 2463 objlist_push_tail(Objlist *list, Obj_Entry *obj) 2464 { 2465 Objlist_Entry *elm; 2466 2467 elm = NEW(Objlist_Entry); 2468 elm->obj = obj; 2469 STAILQ_INSERT_TAIL(list, elm, link); 2470 } 2471 2472 static void 2473 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2474 { 2475 Objlist_Entry *elm, *listelm; 2476 2477 STAILQ_FOREACH(listelm, list, link) { 2478 if (listelm->obj == listobj) 2479 break; 2480 } 2481 elm = NEW(Objlist_Entry); 2482 elm->obj = obj; 2483 if (listelm != NULL) 2484 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2485 else 2486 STAILQ_INSERT_TAIL(list, elm, link); 2487 } 2488 2489 static void 2490 objlist_remove(Objlist *list, Obj_Entry *obj) 2491 { 2492 Objlist_Entry *elm; 2493 2494 if ((elm = objlist_find(list, obj)) != NULL) { 2495 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2496 free(elm); 2497 } 2498 } 2499 2500 /* 2501 * Relocate dag rooted in the specified object. 2502 * Returns 0 on success, or -1 on failure. 2503 */ 2504 2505 static int 2506 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2507 int flags, RtldLockState *lockstate) 2508 { 2509 Objlist_Entry *elm; 2510 int error; 2511 2512 error = 0; 2513 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2514 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2515 lockstate); 2516 if (error == -1) 2517 break; 2518 } 2519 return (error); 2520 } 2521 2522 /* 2523 * Relocate single object. 2524 * Returns 0 on success, or -1 on failure. 2525 */ 2526 static int 2527 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2528 int flags, RtldLockState *lockstate) 2529 { 2530 2531 if (obj->relocated) 2532 return (0); 2533 obj->relocated = true; 2534 if (obj != rtldobj) 2535 dbg("relocating \"%s\"", obj->path); 2536 2537 if (obj->symtab == NULL || obj->strtab == NULL || 2538 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2539 _rtld_error("%s: Shared object has no run-time symbol table", 2540 obj->path); 2541 return (-1); 2542 } 2543 2544 if (obj->textrel) { 2545 /* There are relocations to the write-protected text segment. */ 2546 if (mprotect(obj->mapbase, obj->textsize, 2547 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) { 2548 _rtld_error("%s: Cannot write-enable text segment: %s", 2549 obj->path, rtld_strerror(errno)); 2550 return (-1); 2551 } 2552 } 2553 2554 /* Process the non-PLT non-IFUNC relocations. */ 2555 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2556 return (-1); 2557 2558 if (obj->textrel) { /* Re-protected the text segment. */ 2559 if (mprotect(obj->mapbase, obj->textsize, 2560 PROT_READ|PROT_EXEC) == -1) { 2561 _rtld_error("%s: Cannot write-protect text segment: %s", 2562 obj->path, rtld_strerror(errno)); 2563 return (-1); 2564 } 2565 } 2566 2567 /* Set the special PLT or GOT entries. */ 2568 init_pltgot(obj); 2569 2570 /* Process the PLT relocations. */ 2571 if (reloc_plt(obj) == -1) 2572 return (-1); 2573 /* Relocate the jump slots if we are doing immediate binding. */ 2574 if (obj->bind_now || bind_now) 2575 if (reloc_jmpslots(obj, flags, lockstate) == -1) 2576 return (-1); 2577 2578 /* 2579 * Process the non-PLT IFUNC relocations. The relocations are 2580 * processed in two phases, because IFUNC resolvers may 2581 * reference other symbols, which must be readily processed 2582 * before resolvers are called. 2583 */ 2584 if (obj->non_plt_gnu_ifunc && 2585 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate)) 2586 return (-1); 2587 2588 if (obj->relro_size > 0) { 2589 if (mprotect(obj->relro_page, obj->relro_size, 2590 PROT_READ) == -1) { 2591 _rtld_error("%s: Cannot enforce relro protection: %s", 2592 obj->path, rtld_strerror(errno)); 2593 return (-1); 2594 } 2595 } 2596 2597 /* 2598 * Set up the magic number and version in the Obj_Entry. These 2599 * were checked in the crt1.o from the original ElfKit, so we 2600 * set them for backward compatibility. 2601 */ 2602 obj->magic = RTLD_MAGIC; 2603 obj->version = RTLD_VERSION; 2604 2605 return (0); 2606 } 2607 2608 /* 2609 * Relocate newly-loaded shared objects. The argument is a pointer to 2610 * the Obj_Entry for the first such object. All objects from the first 2611 * to the end of the list of objects are relocated. Returns 0 on success, 2612 * or -1 on failure. 2613 */ 2614 static int 2615 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2616 int flags, RtldLockState *lockstate) 2617 { 2618 Obj_Entry *obj; 2619 int error; 2620 2621 for (error = 0, obj = first; obj != NULL; obj = obj->next) { 2622 error = relocate_object(obj, bind_now, rtldobj, flags, 2623 lockstate); 2624 if (error == -1) 2625 break; 2626 } 2627 return (error); 2628 } 2629 2630 /* 2631 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2632 * referencing STT_GNU_IFUNC symbols is postponed till the other 2633 * relocations are done. The indirect functions specified as 2634 * ifunc are allowed to call other symbols, so we need to have 2635 * objects relocated before asking for resolution from indirects. 2636 * 2637 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2638 * instead of the usual lazy handling of PLT slots. It is 2639 * consistent with how GNU does it. 2640 */ 2641 static int 2642 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2643 RtldLockState *lockstate) 2644 { 2645 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2646 return (-1); 2647 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2648 reloc_gnu_ifunc(obj, flags, lockstate) == -1) 2649 return (-1); 2650 return (0); 2651 } 2652 2653 static int 2654 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags, 2655 RtldLockState *lockstate) 2656 { 2657 Obj_Entry *obj; 2658 2659 for (obj = first; obj != NULL; obj = obj->next) { 2660 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1) 2661 return (-1); 2662 } 2663 return (0); 2664 } 2665 2666 static int 2667 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2668 RtldLockState *lockstate) 2669 { 2670 Objlist_Entry *elm; 2671 2672 STAILQ_FOREACH(elm, list, link) { 2673 if (resolve_object_ifunc(elm->obj, bind_now, flags, 2674 lockstate) == -1) 2675 return (-1); 2676 } 2677 return (0); 2678 } 2679 2680 /* 2681 * Cleanup procedure. It will be called (by the atexit mechanism) just 2682 * before the process exits. 2683 */ 2684 static void 2685 rtld_exit(void) 2686 { 2687 RtldLockState lockstate; 2688 2689 wlock_acquire(rtld_bind_lock, &lockstate); 2690 dbg("rtld_exit()"); 2691 objlist_call_fini(&list_fini, NULL, &lockstate); 2692 /* No need to remove the items from the list, since we are exiting. */ 2693 if (!libmap_disable) 2694 lm_fini(); 2695 lock_release(rtld_bind_lock, &lockstate); 2696 } 2697 2698 /* 2699 * Iterate over a search path, translate each element, and invoke the 2700 * callback on the result. 2701 */ 2702 static void * 2703 path_enumerate(const char *path, path_enum_proc callback, void *arg) 2704 { 2705 const char *trans; 2706 if (path == NULL) 2707 return (NULL); 2708 2709 path += strspn(path, ":;"); 2710 while (*path != '\0') { 2711 size_t len; 2712 char *res; 2713 2714 len = strcspn(path, ":;"); 2715 trans = lm_findn(NULL, path, len); 2716 if (trans) 2717 res = callback(trans, strlen(trans), arg); 2718 else 2719 res = callback(path, len, arg); 2720 2721 if (res != NULL) 2722 return (res); 2723 2724 path += len; 2725 path += strspn(path, ":;"); 2726 } 2727 2728 return (NULL); 2729 } 2730 2731 struct try_library_args { 2732 const char *name; 2733 size_t namelen; 2734 char *buffer; 2735 size_t buflen; 2736 }; 2737 2738 static void * 2739 try_library_path(const char *dir, size_t dirlen, void *param) 2740 { 2741 struct try_library_args *arg; 2742 2743 arg = param; 2744 if (*dir == '/' || trust) { 2745 char *pathname; 2746 2747 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 2748 return (NULL); 2749 2750 pathname = arg->buffer; 2751 strncpy(pathname, dir, dirlen); 2752 pathname[dirlen] = '/'; 2753 strcpy(pathname + dirlen + 1, arg->name); 2754 2755 dbg(" Trying \"%s\"", pathname); 2756 if (access(pathname, F_OK) == 0) { /* We found it */ 2757 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 2758 strcpy(pathname, arg->buffer); 2759 return (pathname); 2760 } 2761 } 2762 return (NULL); 2763 } 2764 2765 static char * 2766 search_library_path(const char *name, const char *path) 2767 { 2768 char *p; 2769 struct try_library_args arg; 2770 2771 if (path == NULL) 2772 return NULL; 2773 2774 arg.name = name; 2775 arg.namelen = strlen(name); 2776 arg.buffer = xmalloc(PATH_MAX); 2777 arg.buflen = PATH_MAX; 2778 2779 p = path_enumerate(path, try_library_path, &arg); 2780 2781 free(arg.buffer); 2782 2783 return (p); 2784 } 2785 2786 2787 /* 2788 * Finds the library with the given name using the directory descriptors 2789 * listed in the LD_LIBRARY_PATH_FDS environment variable. 2790 * 2791 * Returns a freshly-opened close-on-exec file descriptor for the library, 2792 * or -1 if the library cannot be found. 2793 */ 2794 static char * 2795 search_library_pathfds(const char *name, const char *path, int *fdp) 2796 { 2797 char *envcopy, *fdstr, *found, *last_token; 2798 size_t len; 2799 int dirfd, fd; 2800 2801 dbg("%s('%s', '%s', fdp)", __func__, name, path); 2802 2803 /* Don't load from user-specified libdirs into setuid binaries. */ 2804 if (!trust) 2805 return (NULL); 2806 2807 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 2808 if (path == NULL) 2809 return (NULL); 2810 2811 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 2812 if (name[0] == '/') { 2813 dbg("Absolute path (%s) passed to %s", name, __func__); 2814 return (NULL); 2815 } 2816 2817 /* 2818 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 2819 * copy of the path, as strtok_r rewrites separator tokens 2820 * with '\0'. 2821 */ 2822 found = NULL; 2823 envcopy = xstrdup(path); 2824 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 2825 fdstr = strtok_r(NULL, ":", &last_token)) { 2826 dirfd = parse_libdir(fdstr); 2827 if (dirfd < 0) 2828 break; 2829 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC); 2830 if (fd >= 0) { 2831 *fdp = fd; 2832 len = strlen(fdstr) + strlen(name) + 3; 2833 found = xmalloc(len); 2834 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 2835 _rtld_error("error generating '%d/%s'", 2836 dirfd, name); 2837 die(); 2838 } 2839 dbg("open('%s') => %d", found, fd); 2840 break; 2841 } 2842 } 2843 free(envcopy); 2844 2845 return (found); 2846 } 2847 2848 2849 int 2850 dlclose(void *handle) 2851 { 2852 Obj_Entry *root; 2853 RtldLockState lockstate; 2854 2855 wlock_acquire(rtld_bind_lock, &lockstate); 2856 root = dlcheck(handle); 2857 if (root == NULL) { 2858 lock_release(rtld_bind_lock, &lockstate); 2859 return -1; 2860 } 2861 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 2862 root->path); 2863 2864 /* Unreference the object and its dependencies. */ 2865 root->dl_refcount--; 2866 2867 if (root->refcount == 1) { 2868 /* 2869 * The object will be no longer referenced, so we must unload it. 2870 * First, call the fini functions. 2871 */ 2872 objlist_call_fini(&list_fini, root, &lockstate); 2873 2874 unref_dag(root); 2875 2876 /* Finish cleaning up the newly-unreferenced objects. */ 2877 GDB_STATE(RT_DELETE,&root->linkmap); 2878 unload_object(root); 2879 GDB_STATE(RT_CONSISTENT,NULL); 2880 } else 2881 unref_dag(root); 2882 2883 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 2884 lock_release(rtld_bind_lock, &lockstate); 2885 return 0; 2886 } 2887 2888 char * 2889 dlerror(void) 2890 { 2891 char *msg = error_message; 2892 error_message = NULL; 2893 return msg; 2894 } 2895 2896 /* 2897 * This function is deprecated and has no effect. 2898 */ 2899 void 2900 dllockinit(void *context, 2901 void *(*lock_create)(void *context), 2902 void (*rlock_acquire)(void *lock), 2903 void (*wlock_acquire)(void *lock), 2904 void (*lock_release)(void *lock), 2905 void (*lock_destroy)(void *lock), 2906 void (*context_destroy)(void *context)) 2907 { 2908 static void *cur_context; 2909 static void (*cur_context_destroy)(void *); 2910 2911 /* Just destroy the context from the previous call, if necessary. */ 2912 if (cur_context_destroy != NULL) 2913 cur_context_destroy(cur_context); 2914 cur_context = context; 2915 cur_context_destroy = context_destroy; 2916 } 2917 2918 void * 2919 dlopen(const char *name, int mode) 2920 { 2921 2922 return (rtld_dlopen(name, -1, mode)); 2923 } 2924 2925 void * 2926 fdlopen(int fd, int mode) 2927 { 2928 2929 return (rtld_dlopen(NULL, fd, mode)); 2930 } 2931 2932 static void * 2933 rtld_dlopen(const char *name, int fd, int mode) 2934 { 2935 RtldLockState lockstate; 2936 int lo_flags; 2937 2938 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 2939 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 2940 if (ld_tracing != NULL) { 2941 rlock_acquire(rtld_bind_lock, &lockstate); 2942 if (sigsetjmp(lockstate.env, 0) != 0) 2943 lock_upgrade(rtld_bind_lock, &lockstate); 2944 environ = (char **)*get_program_var_addr("environ", &lockstate); 2945 lock_release(rtld_bind_lock, &lockstate); 2946 } 2947 lo_flags = RTLD_LO_DLOPEN; 2948 if (mode & RTLD_NODELETE) 2949 lo_flags |= RTLD_LO_NODELETE; 2950 if (mode & RTLD_NOLOAD) 2951 lo_flags |= RTLD_LO_NOLOAD; 2952 if (ld_tracing != NULL) 2953 lo_flags |= RTLD_LO_TRACE; 2954 2955 return (dlopen_object(name, fd, obj_main, lo_flags, 2956 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 2957 } 2958 2959 static void 2960 dlopen_cleanup(Obj_Entry *obj) 2961 { 2962 2963 obj->dl_refcount--; 2964 unref_dag(obj); 2965 if (obj->refcount == 0) 2966 unload_object(obj); 2967 } 2968 2969 static Obj_Entry * 2970 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 2971 int mode, RtldLockState *lockstate) 2972 { 2973 Obj_Entry **old_obj_tail; 2974 Obj_Entry *obj; 2975 Objlist initlist; 2976 RtldLockState mlockstate; 2977 int result; 2978 2979 objlist_init(&initlist); 2980 2981 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 2982 wlock_acquire(rtld_bind_lock, &mlockstate); 2983 lockstate = &mlockstate; 2984 } 2985 GDB_STATE(RT_ADD,NULL); 2986 2987 old_obj_tail = obj_tail; 2988 obj = NULL; 2989 if (name == NULL && fd == -1) { 2990 obj = obj_main; 2991 obj->refcount++; 2992 } else { 2993 obj = load_object(name, fd, refobj, lo_flags); 2994 } 2995 2996 if (obj) { 2997 obj->dl_refcount++; 2998 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 2999 objlist_push_tail(&list_global, obj); 3000 if (*old_obj_tail != NULL) { /* We loaded something new. */ 3001 assert(*old_obj_tail == obj); 3002 result = load_needed_objects(obj, 3003 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 3004 init_dag(obj); 3005 ref_dag(obj); 3006 if (result != -1) 3007 result = rtld_verify_versions(&obj->dagmembers); 3008 if (result != -1 && ld_tracing) 3009 goto trace; 3010 if (result == -1 || relocate_object_dag(obj, 3011 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3012 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3013 lockstate) == -1) { 3014 dlopen_cleanup(obj); 3015 obj = NULL; 3016 } else if (lo_flags & RTLD_LO_EARLY) { 3017 /* 3018 * Do not call the init functions for early loaded 3019 * filtees. The image is still not initialized enough 3020 * for them to work. 3021 * 3022 * Our object is found by the global object list and 3023 * will be ordered among all init calls done right 3024 * before transferring control to main. 3025 */ 3026 } else { 3027 /* Make list of init functions to call. */ 3028 initlist_add_objects(obj, &obj->next, &initlist); 3029 } 3030 /* 3031 * Process all no_delete objects here, given them own 3032 * DAGs to prevent their dependencies from being unloaded. 3033 * This has to be done after we have loaded all of the 3034 * dependencies, so that we do not miss any. 3035 */ 3036 if (obj != NULL) 3037 process_nodelete(obj); 3038 } else { 3039 /* 3040 * Bump the reference counts for objects on this DAG. If 3041 * this is the first dlopen() call for the object that was 3042 * already loaded as a dependency, initialize the dag 3043 * starting at it. 3044 */ 3045 init_dag(obj); 3046 ref_dag(obj); 3047 3048 if ((lo_flags & RTLD_LO_TRACE) != 0) 3049 goto trace; 3050 } 3051 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3052 obj->z_nodelete) && !obj->ref_nodel) { 3053 dbg("obj %s nodelete", obj->path); 3054 ref_dag(obj); 3055 obj->z_nodelete = obj->ref_nodel = true; 3056 } 3057 } 3058 3059 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3060 name); 3061 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3062 3063 if (!(lo_flags & RTLD_LO_EARLY)) { 3064 map_stacks_exec(lockstate); 3065 } 3066 3067 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3068 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3069 lockstate) == -1) { 3070 objlist_clear(&initlist); 3071 dlopen_cleanup(obj); 3072 if (lockstate == &mlockstate) 3073 lock_release(rtld_bind_lock, lockstate); 3074 return (NULL); 3075 } 3076 3077 if (!(lo_flags & RTLD_LO_EARLY)) { 3078 /* Call the init functions. */ 3079 objlist_call_init(&initlist, lockstate); 3080 } 3081 objlist_clear(&initlist); 3082 if (lockstate == &mlockstate) 3083 lock_release(rtld_bind_lock, lockstate); 3084 return obj; 3085 trace: 3086 trace_loaded_objects(obj); 3087 if (lockstate == &mlockstate) 3088 lock_release(rtld_bind_lock, lockstate); 3089 exit(0); 3090 } 3091 3092 static void * 3093 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3094 int flags) 3095 { 3096 DoneList donelist; 3097 const Obj_Entry *obj, *defobj; 3098 const Elf_Sym *def; 3099 SymLook req; 3100 RtldLockState lockstate; 3101 tls_index ti; 3102 void *sym; 3103 int res; 3104 3105 def = NULL; 3106 defobj = NULL; 3107 symlook_init(&req, name); 3108 req.ventry = ve; 3109 req.flags = flags | SYMLOOK_IN_PLT; 3110 req.lockstate = &lockstate; 3111 3112 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3113 rlock_acquire(rtld_bind_lock, &lockstate); 3114 if (sigsetjmp(lockstate.env, 0) != 0) 3115 lock_upgrade(rtld_bind_lock, &lockstate); 3116 if (handle == NULL || handle == RTLD_NEXT || 3117 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3118 3119 if ((obj = obj_from_addr(retaddr)) == NULL) { 3120 _rtld_error("Cannot determine caller's shared object"); 3121 lock_release(rtld_bind_lock, &lockstate); 3122 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3123 return NULL; 3124 } 3125 if (handle == NULL) { /* Just the caller's shared object. */ 3126 res = symlook_obj(&req, obj); 3127 if (res == 0) { 3128 def = req.sym_out; 3129 defobj = req.defobj_out; 3130 } 3131 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3132 handle == RTLD_SELF) { /* ... caller included */ 3133 if (handle == RTLD_NEXT) 3134 obj = obj->next; 3135 for (; obj != NULL; obj = obj->next) { 3136 res = symlook_obj(&req, obj); 3137 if (res == 0) { 3138 if (def == NULL || 3139 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3140 def = req.sym_out; 3141 defobj = req.defobj_out; 3142 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3143 break; 3144 } 3145 } 3146 } 3147 /* 3148 * Search the dynamic linker itself, and possibly resolve the 3149 * symbol from there. This is how the application links to 3150 * dynamic linker services such as dlopen. 3151 */ 3152 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3153 res = symlook_obj(&req, &obj_rtld); 3154 if (res == 0) { 3155 def = req.sym_out; 3156 defobj = req.defobj_out; 3157 } 3158 } 3159 } else { 3160 assert(handle == RTLD_DEFAULT); 3161 res = symlook_default(&req, obj); 3162 if (res == 0) { 3163 defobj = req.defobj_out; 3164 def = req.sym_out; 3165 } 3166 } 3167 } else { 3168 if ((obj = dlcheck(handle)) == NULL) { 3169 lock_release(rtld_bind_lock, &lockstate); 3170 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3171 return NULL; 3172 } 3173 3174 donelist_init(&donelist); 3175 if (obj->mainprog) { 3176 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3177 res = symlook_global(&req, &donelist); 3178 if (res == 0) { 3179 def = req.sym_out; 3180 defobj = req.defobj_out; 3181 } 3182 /* 3183 * Search the dynamic linker itself, and possibly resolve the 3184 * symbol from there. This is how the application links to 3185 * dynamic linker services such as dlopen. 3186 */ 3187 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3188 res = symlook_obj(&req, &obj_rtld); 3189 if (res == 0) { 3190 def = req.sym_out; 3191 defobj = req.defobj_out; 3192 } 3193 } 3194 } 3195 else { 3196 /* Search the whole DAG rooted at the given object. */ 3197 res = symlook_list(&req, &obj->dagmembers, &donelist); 3198 if (res == 0) { 3199 def = req.sym_out; 3200 defobj = req.defobj_out; 3201 } 3202 } 3203 } 3204 3205 if (def != NULL) { 3206 lock_release(rtld_bind_lock, &lockstate); 3207 3208 /* 3209 * The value required by the caller is derived from the value 3210 * of the symbol. this is simply the relocated value of the 3211 * symbol. 3212 */ 3213 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3214 sym = make_function_pointer(def, defobj); 3215 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3216 sym = rtld_resolve_ifunc(defobj, def); 3217 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3218 ti.ti_module = defobj->tlsindex; 3219 ti.ti_offset = def->st_value; 3220 sym = __tls_get_addr(&ti); 3221 } else 3222 sym = defobj->relocbase + def->st_value; 3223 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3224 return (sym); 3225 } 3226 3227 _rtld_error("Undefined symbol \"%s\"", name); 3228 lock_release(rtld_bind_lock, &lockstate); 3229 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3230 return NULL; 3231 } 3232 3233 void * 3234 dlsym(void *handle, const char *name) 3235 { 3236 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3237 SYMLOOK_DLSYM); 3238 } 3239 3240 dlfunc_t 3241 dlfunc(void *handle, const char *name) 3242 { 3243 union { 3244 void *d; 3245 dlfunc_t f; 3246 } rv; 3247 3248 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3249 SYMLOOK_DLSYM); 3250 return (rv.f); 3251 } 3252 3253 void * 3254 dlvsym(void *handle, const char *name, const char *version) 3255 { 3256 Ver_Entry ventry; 3257 3258 ventry.name = version; 3259 ventry.file = NULL; 3260 ventry.hash = elf_hash(version); 3261 ventry.flags= 0; 3262 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3263 SYMLOOK_DLSYM); 3264 } 3265 3266 int 3267 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3268 { 3269 const Obj_Entry *obj; 3270 RtldLockState lockstate; 3271 3272 rlock_acquire(rtld_bind_lock, &lockstate); 3273 obj = obj_from_addr(addr); 3274 if (obj == NULL) { 3275 _rtld_error("No shared object contains address"); 3276 lock_release(rtld_bind_lock, &lockstate); 3277 return (0); 3278 } 3279 rtld_fill_dl_phdr_info(obj, phdr_info); 3280 lock_release(rtld_bind_lock, &lockstate); 3281 return (1); 3282 } 3283 3284 int 3285 dladdr(const void *addr, Dl_info *info) 3286 { 3287 const Obj_Entry *obj; 3288 const Elf_Sym *def; 3289 void *symbol_addr; 3290 unsigned long symoffset; 3291 RtldLockState lockstate; 3292 3293 rlock_acquire(rtld_bind_lock, &lockstate); 3294 obj = obj_from_addr(addr); 3295 if (obj == NULL) { 3296 _rtld_error("No shared object contains address"); 3297 lock_release(rtld_bind_lock, &lockstate); 3298 return 0; 3299 } 3300 info->dli_fname = obj->path; 3301 info->dli_fbase = obj->mapbase; 3302 info->dli_saddr = (void *)0; 3303 info->dli_sname = NULL; 3304 3305 /* 3306 * Walk the symbol list looking for the symbol whose address is 3307 * closest to the address sent in. 3308 */ 3309 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3310 def = obj->symtab + symoffset; 3311 3312 /* 3313 * For skip the symbol if st_shndx is either SHN_UNDEF or 3314 * SHN_COMMON. 3315 */ 3316 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3317 continue; 3318 3319 /* 3320 * If the symbol is greater than the specified address, or if it 3321 * is further away from addr than the current nearest symbol, 3322 * then reject it. 3323 */ 3324 symbol_addr = obj->relocbase + def->st_value; 3325 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3326 continue; 3327 3328 /* Update our idea of the nearest symbol. */ 3329 info->dli_sname = obj->strtab + def->st_name; 3330 info->dli_saddr = symbol_addr; 3331 3332 /* Exact match? */ 3333 if (info->dli_saddr == addr) 3334 break; 3335 } 3336 lock_release(rtld_bind_lock, &lockstate); 3337 return 1; 3338 } 3339 3340 int 3341 dlinfo(void *handle, int request, void *p) 3342 { 3343 const Obj_Entry *obj; 3344 RtldLockState lockstate; 3345 int error; 3346 3347 rlock_acquire(rtld_bind_lock, &lockstate); 3348 3349 if (handle == NULL || handle == RTLD_SELF) { 3350 void *retaddr; 3351 3352 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3353 if ((obj = obj_from_addr(retaddr)) == NULL) 3354 _rtld_error("Cannot determine caller's shared object"); 3355 } else 3356 obj = dlcheck(handle); 3357 3358 if (obj == NULL) { 3359 lock_release(rtld_bind_lock, &lockstate); 3360 return (-1); 3361 } 3362 3363 error = 0; 3364 switch (request) { 3365 case RTLD_DI_LINKMAP: 3366 *((struct link_map const **)p) = &obj->linkmap; 3367 break; 3368 case RTLD_DI_ORIGIN: 3369 error = rtld_dirname(obj->path, p); 3370 break; 3371 3372 case RTLD_DI_SERINFOSIZE: 3373 case RTLD_DI_SERINFO: 3374 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3375 break; 3376 3377 default: 3378 _rtld_error("Invalid request %d passed to dlinfo()", request); 3379 error = -1; 3380 } 3381 3382 lock_release(rtld_bind_lock, &lockstate); 3383 3384 return (error); 3385 } 3386 3387 static void 3388 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3389 { 3390 3391 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3392 phdr_info->dlpi_name = obj->path; 3393 phdr_info->dlpi_phdr = obj->phdr; 3394 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3395 phdr_info->dlpi_tls_modid = obj->tlsindex; 3396 phdr_info->dlpi_tls_data = obj->tlsinit; 3397 phdr_info->dlpi_adds = obj_loads; 3398 phdr_info->dlpi_subs = obj_loads - obj_count; 3399 } 3400 3401 int 3402 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3403 { 3404 struct dl_phdr_info phdr_info; 3405 const Obj_Entry *obj; 3406 RtldLockState bind_lockstate, phdr_lockstate; 3407 int error; 3408 3409 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3410 rlock_acquire(rtld_bind_lock, &bind_lockstate); 3411 3412 error = 0; 3413 3414 for (obj = obj_list; obj != NULL; obj = obj->next) { 3415 rtld_fill_dl_phdr_info(obj, &phdr_info); 3416 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0) 3417 break; 3418 3419 } 3420 if (error == 0) { 3421 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3422 error = callback(&phdr_info, sizeof(phdr_info), param); 3423 } 3424 3425 lock_release(rtld_bind_lock, &bind_lockstate); 3426 lock_release(rtld_phdr_lock, &phdr_lockstate); 3427 3428 return (error); 3429 } 3430 3431 static void * 3432 fill_search_info(const char *dir, size_t dirlen, void *param) 3433 { 3434 struct fill_search_info_args *arg; 3435 3436 arg = param; 3437 3438 if (arg->request == RTLD_DI_SERINFOSIZE) { 3439 arg->serinfo->dls_cnt ++; 3440 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3441 } else { 3442 struct dl_serpath *s_entry; 3443 3444 s_entry = arg->serpath; 3445 s_entry->dls_name = arg->strspace; 3446 s_entry->dls_flags = arg->flags; 3447 3448 strncpy(arg->strspace, dir, dirlen); 3449 arg->strspace[dirlen] = '\0'; 3450 3451 arg->strspace += dirlen + 1; 3452 arg->serpath++; 3453 } 3454 3455 return (NULL); 3456 } 3457 3458 static int 3459 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3460 { 3461 struct dl_serinfo _info; 3462 struct fill_search_info_args args; 3463 3464 args.request = RTLD_DI_SERINFOSIZE; 3465 args.serinfo = &_info; 3466 3467 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3468 _info.dls_cnt = 0; 3469 3470 path_enumerate(obj->rpath, fill_search_info, &args); 3471 path_enumerate(ld_library_path, fill_search_info, &args); 3472 path_enumerate(obj->runpath, fill_search_info, &args); 3473 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args); 3474 if (!obj->z_nodeflib) 3475 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 3476 3477 3478 if (request == RTLD_DI_SERINFOSIZE) { 3479 info->dls_size = _info.dls_size; 3480 info->dls_cnt = _info.dls_cnt; 3481 return (0); 3482 } 3483 3484 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3485 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3486 return (-1); 3487 } 3488 3489 args.request = RTLD_DI_SERINFO; 3490 args.serinfo = info; 3491 args.serpath = &info->dls_serpath[0]; 3492 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3493 3494 args.flags = LA_SER_RUNPATH; 3495 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 3496 return (-1); 3497 3498 args.flags = LA_SER_LIBPATH; 3499 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 3500 return (-1); 3501 3502 args.flags = LA_SER_RUNPATH; 3503 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL) 3504 return (-1); 3505 3506 args.flags = LA_SER_CONFIG; 3507 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args) 3508 != NULL) 3509 return (-1); 3510 3511 args.flags = LA_SER_DEFAULT; 3512 if (!obj->z_nodeflib && 3513 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 3514 return (-1); 3515 return (0); 3516 } 3517 3518 static int 3519 rtld_dirname(const char *path, char *bname) 3520 { 3521 const char *endp; 3522 3523 /* Empty or NULL string gets treated as "." */ 3524 if (path == NULL || *path == '\0') { 3525 bname[0] = '.'; 3526 bname[1] = '\0'; 3527 return (0); 3528 } 3529 3530 /* Strip trailing slashes */ 3531 endp = path + strlen(path) - 1; 3532 while (endp > path && *endp == '/') 3533 endp--; 3534 3535 /* Find the start of the dir */ 3536 while (endp > path && *endp != '/') 3537 endp--; 3538 3539 /* Either the dir is "/" or there are no slashes */ 3540 if (endp == path) { 3541 bname[0] = *endp == '/' ? '/' : '.'; 3542 bname[1] = '\0'; 3543 return (0); 3544 } else { 3545 do { 3546 endp--; 3547 } while (endp > path && *endp == '/'); 3548 } 3549 3550 if (endp - path + 2 > PATH_MAX) 3551 { 3552 _rtld_error("Filename is too long: %s", path); 3553 return(-1); 3554 } 3555 3556 strncpy(bname, path, endp - path + 1); 3557 bname[endp - path + 1] = '\0'; 3558 return (0); 3559 } 3560 3561 static int 3562 rtld_dirname_abs(const char *path, char *base) 3563 { 3564 char base_rel[PATH_MAX]; 3565 3566 if (rtld_dirname(path, base) == -1) 3567 return (-1); 3568 if (base[0] == '/') 3569 return (0); 3570 if (getcwd(base_rel, sizeof(base_rel)) == NULL || 3571 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) || 3572 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel)) 3573 return (-1); 3574 strcpy(base, base_rel); 3575 return (0); 3576 } 3577 3578 static void 3579 linkmap_add(Obj_Entry *obj) 3580 { 3581 struct link_map *l = &obj->linkmap; 3582 struct link_map *prev; 3583 3584 obj->linkmap.l_name = obj->path; 3585 obj->linkmap.l_addr = obj->mapbase; 3586 obj->linkmap.l_ld = obj->dynamic; 3587 #ifdef __mips__ 3588 /* GDB needs load offset on MIPS to use the symbols */ 3589 obj->linkmap.l_offs = obj->relocbase; 3590 #endif 3591 3592 if (r_debug.r_map == NULL) { 3593 r_debug.r_map = l; 3594 return; 3595 } 3596 3597 /* 3598 * Scan to the end of the list, but not past the entry for the 3599 * dynamic linker, which we want to keep at the very end. 3600 */ 3601 for (prev = r_debug.r_map; 3602 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3603 prev = prev->l_next) 3604 ; 3605 3606 /* Link in the new entry. */ 3607 l->l_prev = prev; 3608 l->l_next = prev->l_next; 3609 if (l->l_next != NULL) 3610 l->l_next->l_prev = l; 3611 prev->l_next = l; 3612 } 3613 3614 static void 3615 linkmap_delete(Obj_Entry *obj) 3616 { 3617 struct link_map *l = &obj->linkmap; 3618 3619 if (l->l_prev == NULL) { 3620 if ((r_debug.r_map = l->l_next) != NULL) 3621 l->l_next->l_prev = NULL; 3622 return; 3623 } 3624 3625 if ((l->l_prev->l_next = l->l_next) != NULL) 3626 l->l_next->l_prev = l->l_prev; 3627 } 3628 3629 /* 3630 * Function for the debugger to set a breakpoint on to gain control. 3631 * 3632 * The two parameters allow the debugger to easily find and determine 3633 * what the runtime loader is doing and to whom it is doing it. 3634 * 3635 * When the loadhook trap is hit (r_debug_state, set at program 3636 * initialization), the arguments can be found on the stack: 3637 * 3638 * +8 struct link_map *m 3639 * +4 struct r_debug *rd 3640 * +0 RetAddr 3641 */ 3642 void 3643 r_debug_state(struct r_debug* rd, struct link_map *m) 3644 { 3645 /* 3646 * The following is a hack to force the compiler to emit calls to 3647 * this function, even when optimizing. If the function is empty, 3648 * the compiler is not obliged to emit any code for calls to it, 3649 * even when marked __noinline. However, gdb depends on those 3650 * calls being made. 3651 */ 3652 __compiler_membar(); 3653 } 3654 3655 /* 3656 * A function called after init routines have completed. This can be used to 3657 * break before a program's entry routine is called, and can be used when 3658 * main is not available in the symbol table. 3659 */ 3660 void 3661 _r_debug_postinit(struct link_map *m) 3662 { 3663 3664 /* See r_debug_state(). */ 3665 __compiler_membar(); 3666 } 3667 3668 /* 3669 * Get address of the pointer variable in the main program. 3670 * Prefer non-weak symbol over the weak one. 3671 */ 3672 static const void ** 3673 get_program_var_addr(const char *name, RtldLockState *lockstate) 3674 { 3675 SymLook req; 3676 DoneList donelist; 3677 3678 symlook_init(&req, name); 3679 req.lockstate = lockstate; 3680 donelist_init(&donelist); 3681 if (symlook_global(&req, &donelist) != 0) 3682 return (NULL); 3683 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 3684 return ((const void **)make_function_pointer(req.sym_out, 3685 req.defobj_out)); 3686 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 3687 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 3688 else 3689 return ((const void **)(req.defobj_out->relocbase + 3690 req.sym_out->st_value)); 3691 } 3692 3693 /* 3694 * Set a pointer variable in the main program to the given value. This 3695 * is used to set key variables such as "environ" before any of the 3696 * init functions are called. 3697 */ 3698 static void 3699 set_program_var(const char *name, const void *value) 3700 { 3701 const void **addr; 3702 3703 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 3704 dbg("\"%s\": *%p <-- %p", name, addr, value); 3705 *addr = value; 3706 } 3707 } 3708 3709 /* 3710 * Search the global objects, including dependencies and main object, 3711 * for the given symbol. 3712 */ 3713 static int 3714 symlook_global(SymLook *req, DoneList *donelist) 3715 { 3716 SymLook req1; 3717 const Objlist_Entry *elm; 3718 int res; 3719 3720 symlook_init_from_req(&req1, req); 3721 3722 /* Search all objects loaded at program start up. */ 3723 if (req->defobj_out == NULL || 3724 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3725 res = symlook_list(&req1, &list_main, donelist); 3726 if (res == 0 && (req->defobj_out == NULL || 3727 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3728 req->sym_out = req1.sym_out; 3729 req->defobj_out = req1.defobj_out; 3730 assert(req->defobj_out != NULL); 3731 } 3732 } 3733 3734 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 3735 STAILQ_FOREACH(elm, &list_global, link) { 3736 if (req->defobj_out != NULL && 3737 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3738 break; 3739 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 3740 if (res == 0 && (req->defobj_out == NULL || 3741 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3742 req->sym_out = req1.sym_out; 3743 req->defobj_out = req1.defobj_out; 3744 assert(req->defobj_out != NULL); 3745 } 3746 } 3747 3748 return (req->sym_out != NULL ? 0 : ESRCH); 3749 } 3750 3751 /* 3752 * Given a symbol name in a referencing object, find the corresponding 3753 * definition of the symbol. Returns a pointer to the symbol, or NULL if 3754 * no definition was found. Returns a pointer to the Obj_Entry of the 3755 * defining object via the reference parameter DEFOBJ_OUT. 3756 */ 3757 static int 3758 symlook_default(SymLook *req, const Obj_Entry *refobj) 3759 { 3760 DoneList donelist; 3761 const Objlist_Entry *elm; 3762 SymLook req1; 3763 int res; 3764 3765 donelist_init(&donelist); 3766 symlook_init_from_req(&req1, req); 3767 3768 /* Look first in the referencing object if linked symbolically. */ 3769 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 3770 res = symlook_obj(&req1, refobj); 3771 if (res == 0) { 3772 req->sym_out = req1.sym_out; 3773 req->defobj_out = req1.defobj_out; 3774 assert(req->defobj_out != NULL); 3775 } 3776 } 3777 3778 symlook_global(req, &donelist); 3779 3780 /* Search all dlopened DAGs containing the referencing object. */ 3781 STAILQ_FOREACH(elm, &refobj->dldags, link) { 3782 if (req->sym_out != NULL && 3783 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3784 break; 3785 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 3786 if (res == 0 && (req->sym_out == NULL || 3787 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3788 req->sym_out = req1.sym_out; 3789 req->defobj_out = req1.defobj_out; 3790 assert(req->defobj_out != NULL); 3791 } 3792 } 3793 3794 /* 3795 * Search the dynamic linker itself, and possibly resolve the 3796 * symbol from there. This is how the application links to 3797 * dynamic linker services such as dlopen. 3798 */ 3799 if (req->sym_out == NULL || 3800 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3801 res = symlook_obj(&req1, &obj_rtld); 3802 if (res == 0) { 3803 req->sym_out = req1.sym_out; 3804 req->defobj_out = req1.defobj_out; 3805 assert(req->defobj_out != NULL); 3806 } 3807 } 3808 3809 return (req->sym_out != NULL ? 0 : ESRCH); 3810 } 3811 3812 static int 3813 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 3814 { 3815 const Elf_Sym *def; 3816 const Obj_Entry *defobj; 3817 const Objlist_Entry *elm; 3818 SymLook req1; 3819 int res; 3820 3821 def = NULL; 3822 defobj = NULL; 3823 STAILQ_FOREACH(elm, objlist, link) { 3824 if (donelist_check(dlp, elm->obj)) 3825 continue; 3826 symlook_init_from_req(&req1, req); 3827 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 3828 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3829 def = req1.sym_out; 3830 defobj = req1.defobj_out; 3831 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3832 break; 3833 } 3834 } 3835 } 3836 if (def != NULL) { 3837 req->sym_out = def; 3838 req->defobj_out = defobj; 3839 return (0); 3840 } 3841 return (ESRCH); 3842 } 3843 3844 /* 3845 * Search the chain of DAGS cointed to by the given Needed_Entry 3846 * for a symbol of the given name. Each DAG is scanned completely 3847 * before advancing to the next one. Returns a pointer to the symbol, 3848 * or NULL if no definition was found. 3849 */ 3850 static int 3851 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 3852 { 3853 const Elf_Sym *def; 3854 const Needed_Entry *n; 3855 const Obj_Entry *defobj; 3856 SymLook req1; 3857 int res; 3858 3859 def = NULL; 3860 defobj = NULL; 3861 symlook_init_from_req(&req1, req); 3862 for (n = needed; n != NULL; n = n->next) { 3863 if (n->obj == NULL || 3864 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 3865 continue; 3866 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3867 def = req1.sym_out; 3868 defobj = req1.defobj_out; 3869 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3870 break; 3871 } 3872 } 3873 if (def != NULL) { 3874 req->sym_out = def; 3875 req->defobj_out = defobj; 3876 return (0); 3877 } 3878 return (ESRCH); 3879 } 3880 3881 /* 3882 * Search the symbol table of a single shared object for a symbol of 3883 * the given name and version, if requested. Returns a pointer to the 3884 * symbol, or NULL if no definition was found. If the object is 3885 * filter, return filtered symbol from filtee. 3886 * 3887 * The symbol's hash value is passed in for efficiency reasons; that 3888 * eliminates many recomputations of the hash value. 3889 */ 3890 int 3891 symlook_obj(SymLook *req, const Obj_Entry *obj) 3892 { 3893 DoneList donelist; 3894 SymLook req1; 3895 int flags, res, mres; 3896 3897 /* 3898 * If there is at least one valid hash at this point, we prefer to 3899 * use the faster GNU version if available. 3900 */ 3901 if (obj->valid_hash_gnu) 3902 mres = symlook_obj1_gnu(req, obj); 3903 else if (obj->valid_hash_sysv) 3904 mres = symlook_obj1_sysv(req, obj); 3905 else 3906 return (EINVAL); 3907 3908 if (mres == 0) { 3909 if (obj->needed_filtees != NULL) { 3910 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3911 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3912 donelist_init(&donelist); 3913 symlook_init_from_req(&req1, req); 3914 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 3915 if (res == 0) { 3916 req->sym_out = req1.sym_out; 3917 req->defobj_out = req1.defobj_out; 3918 } 3919 return (res); 3920 } 3921 if (obj->needed_aux_filtees != NULL) { 3922 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3923 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3924 donelist_init(&donelist); 3925 symlook_init_from_req(&req1, req); 3926 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 3927 if (res == 0) { 3928 req->sym_out = req1.sym_out; 3929 req->defobj_out = req1.defobj_out; 3930 return (res); 3931 } 3932 } 3933 } 3934 return (mres); 3935 } 3936 3937 /* Symbol match routine common to both hash functions */ 3938 static bool 3939 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 3940 const unsigned long symnum) 3941 { 3942 Elf_Versym verndx; 3943 const Elf_Sym *symp; 3944 const char *strp; 3945 3946 symp = obj->symtab + symnum; 3947 strp = obj->strtab + symp->st_name; 3948 3949 switch (ELF_ST_TYPE(symp->st_info)) { 3950 case STT_FUNC: 3951 case STT_NOTYPE: 3952 case STT_OBJECT: 3953 case STT_COMMON: 3954 case STT_GNU_IFUNC: 3955 if (symp->st_value == 0) 3956 return (false); 3957 /* fallthrough */ 3958 case STT_TLS: 3959 if (symp->st_shndx != SHN_UNDEF) 3960 break; 3961 #ifndef __mips__ 3962 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 3963 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 3964 break; 3965 /* fallthrough */ 3966 #endif 3967 default: 3968 return (false); 3969 } 3970 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 3971 return (false); 3972 3973 if (req->ventry == NULL) { 3974 if (obj->versyms != NULL) { 3975 verndx = VER_NDX(obj->versyms[symnum]); 3976 if (verndx > obj->vernum) { 3977 _rtld_error( 3978 "%s: symbol %s references wrong version %d", 3979 obj->path, obj->strtab + symnum, verndx); 3980 return (false); 3981 } 3982 /* 3983 * If we are not called from dlsym (i.e. this 3984 * is a normal relocation from unversioned 3985 * binary), accept the symbol immediately if 3986 * it happens to have first version after this 3987 * shared object became versioned. Otherwise, 3988 * if symbol is versioned and not hidden, 3989 * remember it. If it is the only symbol with 3990 * this name exported by the shared object, it 3991 * will be returned as a match by the calling 3992 * function. If symbol is global (verndx < 2) 3993 * accept it unconditionally. 3994 */ 3995 if ((req->flags & SYMLOOK_DLSYM) == 0 && 3996 verndx == VER_NDX_GIVEN) { 3997 result->sym_out = symp; 3998 return (true); 3999 } 4000 else if (verndx >= VER_NDX_GIVEN) { 4001 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4002 == 0) { 4003 if (result->vsymp == NULL) 4004 result->vsymp = symp; 4005 result->vcount++; 4006 } 4007 return (false); 4008 } 4009 } 4010 result->sym_out = symp; 4011 return (true); 4012 } 4013 if (obj->versyms == NULL) { 4014 if (object_match_name(obj, req->ventry->name)) { 4015 _rtld_error("%s: object %s should provide version %s " 4016 "for symbol %s", obj_rtld.path, obj->path, 4017 req->ventry->name, obj->strtab + symnum); 4018 return (false); 4019 } 4020 } else { 4021 verndx = VER_NDX(obj->versyms[symnum]); 4022 if (verndx > obj->vernum) { 4023 _rtld_error("%s: symbol %s references wrong version %d", 4024 obj->path, obj->strtab + symnum, verndx); 4025 return (false); 4026 } 4027 if (obj->vertab[verndx].hash != req->ventry->hash || 4028 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4029 /* 4030 * Version does not match. Look if this is a 4031 * global symbol and if it is not hidden. If 4032 * global symbol (verndx < 2) is available, 4033 * use it. Do not return symbol if we are 4034 * called by dlvsym, because dlvsym looks for 4035 * a specific version and default one is not 4036 * what dlvsym wants. 4037 */ 4038 if ((req->flags & SYMLOOK_DLSYM) || 4039 (verndx >= VER_NDX_GIVEN) || 4040 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4041 return (false); 4042 } 4043 } 4044 result->sym_out = symp; 4045 return (true); 4046 } 4047 4048 /* 4049 * Search for symbol using SysV hash function. 4050 * obj->buckets is known not to be NULL at this point; the test for this was 4051 * performed with the obj->valid_hash_sysv assignment. 4052 */ 4053 static int 4054 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4055 { 4056 unsigned long symnum; 4057 Sym_Match_Result matchres; 4058 4059 matchres.sym_out = NULL; 4060 matchres.vsymp = NULL; 4061 matchres.vcount = 0; 4062 4063 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4064 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4065 if (symnum >= obj->nchains) 4066 return (ESRCH); /* Bad object */ 4067 4068 if (matched_symbol(req, obj, &matchres, symnum)) { 4069 req->sym_out = matchres.sym_out; 4070 req->defobj_out = obj; 4071 return (0); 4072 } 4073 } 4074 if (matchres.vcount == 1) { 4075 req->sym_out = matchres.vsymp; 4076 req->defobj_out = obj; 4077 return (0); 4078 } 4079 return (ESRCH); 4080 } 4081 4082 /* Search for symbol using GNU hash function */ 4083 static int 4084 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4085 { 4086 Elf_Addr bloom_word; 4087 const Elf32_Word *hashval; 4088 Elf32_Word bucket; 4089 Sym_Match_Result matchres; 4090 unsigned int h1, h2; 4091 unsigned long symnum; 4092 4093 matchres.sym_out = NULL; 4094 matchres.vsymp = NULL; 4095 matchres.vcount = 0; 4096 4097 /* Pick right bitmask word from Bloom filter array */ 4098 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4099 obj->maskwords_bm_gnu]; 4100 4101 /* Calculate modulus word size of gnu hash and its derivative */ 4102 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4103 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4104 4105 /* Filter out the "definitely not in set" queries */ 4106 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4107 return (ESRCH); 4108 4109 /* Locate hash chain and corresponding value element*/ 4110 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4111 if (bucket == 0) 4112 return (ESRCH); 4113 hashval = &obj->chain_zero_gnu[bucket]; 4114 do { 4115 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4116 symnum = hashval - obj->chain_zero_gnu; 4117 if (matched_symbol(req, obj, &matchres, symnum)) { 4118 req->sym_out = matchres.sym_out; 4119 req->defobj_out = obj; 4120 return (0); 4121 } 4122 } 4123 } while ((*hashval++ & 1) == 0); 4124 if (matchres.vcount == 1) { 4125 req->sym_out = matchres.vsymp; 4126 req->defobj_out = obj; 4127 return (0); 4128 } 4129 return (ESRCH); 4130 } 4131 4132 static void 4133 trace_loaded_objects(Obj_Entry *obj) 4134 { 4135 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4136 int c; 4137 4138 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 4139 main_local = ""; 4140 4141 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL) 4142 fmt1 = "\t%o => %p (%x)\n"; 4143 4144 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL) 4145 fmt2 = "\t%o (%x)\n"; 4146 4147 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL"); 4148 4149 for (; obj; obj = obj->next) { 4150 Needed_Entry *needed; 4151 char *name, *path; 4152 bool is_lib; 4153 4154 if (list_containers && obj->needed != NULL) 4155 rtld_printf("%s:\n", obj->path); 4156 for (needed = obj->needed; needed; needed = needed->next) { 4157 if (needed->obj != NULL) { 4158 if (needed->obj->traced && !list_containers) 4159 continue; 4160 needed->obj->traced = true; 4161 path = needed->obj->path; 4162 } else 4163 path = "not found"; 4164 4165 name = (char *)obj->strtab + needed->name; 4166 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4167 4168 fmt = is_lib ? fmt1 : fmt2; 4169 while ((c = *fmt++) != '\0') { 4170 switch (c) { 4171 default: 4172 rtld_putchar(c); 4173 continue; 4174 case '\\': 4175 switch (c = *fmt) { 4176 case '\0': 4177 continue; 4178 case 'n': 4179 rtld_putchar('\n'); 4180 break; 4181 case 't': 4182 rtld_putchar('\t'); 4183 break; 4184 } 4185 break; 4186 case '%': 4187 switch (c = *fmt) { 4188 case '\0': 4189 continue; 4190 case '%': 4191 default: 4192 rtld_putchar(c); 4193 break; 4194 case 'A': 4195 rtld_putstr(main_local); 4196 break; 4197 case 'a': 4198 rtld_putstr(obj_main->path); 4199 break; 4200 case 'o': 4201 rtld_putstr(name); 4202 break; 4203 #if 0 4204 case 'm': 4205 rtld_printf("%d", sodp->sod_major); 4206 break; 4207 case 'n': 4208 rtld_printf("%d", sodp->sod_minor); 4209 break; 4210 #endif 4211 case 'p': 4212 rtld_putstr(path); 4213 break; 4214 case 'x': 4215 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4216 0); 4217 break; 4218 } 4219 break; 4220 } 4221 ++fmt; 4222 } 4223 } 4224 } 4225 } 4226 4227 /* 4228 * Unload a dlopened object and its dependencies from memory and from 4229 * our data structures. It is assumed that the DAG rooted in the 4230 * object has already been unreferenced, and that the object has a 4231 * reference count of 0. 4232 */ 4233 static void 4234 unload_object(Obj_Entry *root) 4235 { 4236 Obj_Entry *obj; 4237 Obj_Entry **linkp; 4238 4239 assert(root->refcount == 0); 4240 4241 /* 4242 * Pass over the DAG removing unreferenced objects from 4243 * appropriate lists. 4244 */ 4245 unlink_object(root); 4246 4247 /* Unmap all objects that are no longer referenced. */ 4248 linkp = &obj_list->next; 4249 while ((obj = *linkp) != NULL) { 4250 if (obj->refcount == 0) { 4251 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 4252 obj->path); 4253 dbg("unloading \"%s\"", obj->path); 4254 unload_filtees(root); 4255 munmap(obj->mapbase, obj->mapsize); 4256 linkmap_delete(obj); 4257 *linkp = obj->next; 4258 obj_count--; 4259 obj_free(obj); 4260 } else 4261 linkp = &obj->next; 4262 } 4263 obj_tail = linkp; 4264 } 4265 4266 static void 4267 unlink_object(Obj_Entry *root) 4268 { 4269 Objlist_Entry *elm; 4270 4271 if (root->refcount == 0) { 4272 /* Remove the object from the RTLD_GLOBAL list. */ 4273 objlist_remove(&list_global, root); 4274 4275 /* Remove the object from all objects' DAG lists. */ 4276 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4277 objlist_remove(&elm->obj->dldags, root); 4278 if (elm->obj != root) 4279 unlink_object(elm->obj); 4280 } 4281 } 4282 } 4283 4284 static void 4285 ref_dag(Obj_Entry *root) 4286 { 4287 Objlist_Entry *elm; 4288 4289 assert(root->dag_inited); 4290 STAILQ_FOREACH(elm, &root->dagmembers, link) 4291 elm->obj->refcount++; 4292 } 4293 4294 static void 4295 unref_dag(Obj_Entry *root) 4296 { 4297 Objlist_Entry *elm; 4298 4299 assert(root->dag_inited); 4300 STAILQ_FOREACH(elm, &root->dagmembers, link) 4301 elm->obj->refcount--; 4302 } 4303 4304 /* 4305 * Common code for MD __tls_get_addr(). 4306 */ 4307 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4308 static void * 4309 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4310 { 4311 Elf_Addr *newdtv, *dtv; 4312 RtldLockState lockstate; 4313 int to_copy; 4314 4315 dtv = *dtvp; 4316 /* Check dtv generation in case new modules have arrived */ 4317 if (dtv[0] != tls_dtv_generation) { 4318 wlock_acquire(rtld_bind_lock, &lockstate); 4319 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4320 to_copy = dtv[1]; 4321 if (to_copy > tls_max_index) 4322 to_copy = tls_max_index; 4323 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4324 newdtv[0] = tls_dtv_generation; 4325 newdtv[1] = tls_max_index; 4326 free(dtv); 4327 lock_release(rtld_bind_lock, &lockstate); 4328 dtv = *dtvp = newdtv; 4329 } 4330 4331 /* Dynamically allocate module TLS if necessary */ 4332 if (dtv[index + 1] == 0) { 4333 /* Signal safe, wlock will block out signals. */ 4334 wlock_acquire(rtld_bind_lock, &lockstate); 4335 if (!dtv[index + 1]) 4336 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4337 lock_release(rtld_bind_lock, &lockstate); 4338 } 4339 return ((void *)(dtv[index + 1] + offset)); 4340 } 4341 4342 void * 4343 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4344 { 4345 Elf_Addr *dtv; 4346 4347 dtv = *dtvp; 4348 /* Check dtv generation in case new modules have arrived */ 4349 if (__predict_true(dtv[0] == tls_dtv_generation && 4350 dtv[index + 1] != 0)) 4351 return ((void *)(dtv[index + 1] + offset)); 4352 return (tls_get_addr_slow(dtvp, index, offset)); 4353 } 4354 4355 #if defined(__arm__) || defined(__mips__) || defined(__powerpc__) 4356 4357 /* 4358 * Allocate Static TLS using the Variant I method. 4359 */ 4360 void * 4361 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4362 { 4363 Obj_Entry *obj; 4364 char *tcb; 4365 Elf_Addr **tls; 4366 Elf_Addr *dtv; 4367 Elf_Addr addr; 4368 int i; 4369 4370 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4371 return (oldtcb); 4372 4373 assert(tcbsize >= TLS_TCB_SIZE); 4374 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 4375 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 4376 4377 if (oldtcb != NULL) { 4378 memcpy(tls, oldtcb, tls_static_space); 4379 free(oldtcb); 4380 4381 /* Adjust the DTV. */ 4382 dtv = tls[0]; 4383 for (i = 0; i < dtv[1]; i++) { 4384 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4385 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4386 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 4387 } 4388 } 4389 } else { 4390 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4391 tls[0] = dtv; 4392 dtv[0] = tls_dtv_generation; 4393 dtv[1] = tls_max_index; 4394 4395 for (obj = objs; obj; obj = obj->next) { 4396 if (obj->tlsoffset > 0) { 4397 addr = (Elf_Addr)tls + obj->tlsoffset; 4398 if (obj->tlsinitsize > 0) 4399 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4400 if (obj->tlssize > obj->tlsinitsize) 4401 memset((void*) (addr + obj->tlsinitsize), 0, 4402 obj->tlssize - obj->tlsinitsize); 4403 dtv[obj->tlsindex + 1] = addr; 4404 } 4405 } 4406 } 4407 4408 return (tcb); 4409 } 4410 4411 void 4412 free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4413 { 4414 Elf_Addr *dtv; 4415 Elf_Addr tlsstart, tlsend; 4416 int dtvsize, i; 4417 4418 assert(tcbsize >= TLS_TCB_SIZE); 4419 4420 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 4421 tlsend = tlsstart + tls_static_space; 4422 4423 dtv = *(Elf_Addr **)tlsstart; 4424 dtvsize = dtv[1]; 4425 for (i = 0; i < dtvsize; i++) { 4426 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4427 free((void*)dtv[i+2]); 4428 } 4429 } 4430 free(dtv); 4431 free(tcb); 4432 } 4433 4434 #endif 4435 4436 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 4437 4438 /* 4439 * Allocate Static TLS using the Variant II method. 4440 */ 4441 void * 4442 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4443 { 4444 Obj_Entry *obj; 4445 size_t size, ralign; 4446 char *tls; 4447 Elf_Addr *dtv, *olddtv; 4448 Elf_Addr segbase, oldsegbase, addr; 4449 int i; 4450 4451 ralign = tcbalign; 4452 if (tls_static_max_align > ralign) 4453 ralign = tls_static_max_align; 4454 size = round(tls_static_space, ralign) + round(tcbsize, ralign); 4455 4456 assert(tcbsize >= 2*sizeof(Elf_Addr)); 4457 tls = malloc_aligned(size, ralign); 4458 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4459 4460 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign)); 4461 ((Elf_Addr*)segbase)[0] = segbase; 4462 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 4463 4464 dtv[0] = tls_dtv_generation; 4465 dtv[1] = tls_max_index; 4466 4467 if (oldtls) { 4468 /* 4469 * Copy the static TLS block over whole. 4470 */ 4471 oldsegbase = (Elf_Addr) oldtls; 4472 memcpy((void *)(segbase - tls_static_space), 4473 (const void *)(oldsegbase - tls_static_space), 4474 tls_static_space); 4475 4476 /* 4477 * If any dynamic TLS blocks have been created tls_get_addr(), 4478 * move them over. 4479 */ 4480 olddtv = ((Elf_Addr**)oldsegbase)[1]; 4481 for (i = 0; i < olddtv[1]; i++) { 4482 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 4483 dtv[i+2] = olddtv[i+2]; 4484 olddtv[i+2] = 0; 4485 } 4486 } 4487 4488 /* 4489 * We assume that this block was the one we created with 4490 * allocate_initial_tls(). 4491 */ 4492 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 4493 } else { 4494 for (obj = objs; obj; obj = obj->next) { 4495 if (obj->tlsoffset) { 4496 addr = segbase - obj->tlsoffset; 4497 memset((void*) (addr + obj->tlsinitsize), 4498 0, obj->tlssize - obj->tlsinitsize); 4499 if (obj->tlsinit) 4500 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4501 dtv[obj->tlsindex + 1] = addr; 4502 } 4503 } 4504 } 4505 4506 return (void*) segbase; 4507 } 4508 4509 void 4510 free_tls(void *tls, size_t tcbsize, size_t tcbalign) 4511 { 4512 Elf_Addr* dtv; 4513 size_t size, ralign; 4514 int dtvsize, i; 4515 Elf_Addr tlsstart, tlsend; 4516 4517 /* 4518 * Figure out the size of the initial TLS block so that we can 4519 * find stuff which ___tls_get_addr() allocated dynamically. 4520 */ 4521 ralign = tcbalign; 4522 if (tls_static_max_align > ralign) 4523 ralign = tls_static_max_align; 4524 size = round(tls_static_space, ralign); 4525 4526 dtv = ((Elf_Addr**)tls)[1]; 4527 dtvsize = dtv[1]; 4528 tlsend = (Elf_Addr) tls; 4529 tlsstart = tlsend - size; 4530 for (i = 0; i < dtvsize; i++) { 4531 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 4532 free_aligned((void *)dtv[i + 2]); 4533 } 4534 } 4535 4536 free_aligned((void *)tlsstart); 4537 free((void*) dtv); 4538 } 4539 4540 #endif 4541 4542 /* 4543 * Allocate TLS block for module with given index. 4544 */ 4545 void * 4546 allocate_module_tls(int index) 4547 { 4548 Obj_Entry* obj; 4549 char* p; 4550 4551 for (obj = obj_list; obj; obj = obj->next) { 4552 if (obj->tlsindex == index) 4553 break; 4554 } 4555 if (!obj) { 4556 _rtld_error("Can't find module with TLS index %d", index); 4557 die(); 4558 } 4559 4560 p = malloc_aligned(obj->tlssize, obj->tlsalign); 4561 memcpy(p, obj->tlsinit, obj->tlsinitsize); 4562 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 4563 4564 return p; 4565 } 4566 4567 bool 4568 allocate_tls_offset(Obj_Entry *obj) 4569 { 4570 size_t off; 4571 4572 if (obj->tls_done) 4573 return true; 4574 4575 if (obj->tlssize == 0) { 4576 obj->tls_done = true; 4577 return true; 4578 } 4579 4580 if (obj->tlsindex == 1) 4581 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 4582 else 4583 off = calculate_tls_offset(tls_last_offset, tls_last_size, 4584 obj->tlssize, obj->tlsalign); 4585 4586 /* 4587 * If we have already fixed the size of the static TLS block, we 4588 * must stay within that size. When allocating the static TLS, we 4589 * leave a small amount of space spare to be used for dynamically 4590 * loading modules which use static TLS. 4591 */ 4592 if (tls_static_space != 0) { 4593 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 4594 return false; 4595 } else if (obj->tlsalign > tls_static_max_align) { 4596 tls_static_max_align = obj->tlsalign; 4597 } 4598 4599 tls_last_offset = obj->tlsoffset = off; 4600 tls_last_size = obj->tlssize; 4601 obj->tls_done = true; 4602 4603 return true; 4604 } 4605 4606 void 4607 free_tls_offset(Obj_Entry *obj) 4608 { 4609 4610 /* 4611 * If we were the last thing to allocate out of the static TLS 4612 * block, we give our space back to the 'allocator'. This is a 4613 * simplistic workaround to allow libGL.so.1 to be loaded and 4614 * unloaded multiple times. 4615 */ 4616 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 4617 == calculate_tls_end(tls_last_offset, tls_last_size)) { 4618 tls_last_offset -= obj->tlssize; 4619 tls_last_size = 0; 4620 } 4621 } 4622 4623 void * 4624 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 4625 { 4626 void *ret; 4627 RtldLockState lockstate; 4628 4629 wlock_acquire(rtld_bind_lock, &lockstate); 4630 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign); 4631 lock_release(rtld_bind_lock, &lockstate); 4632 return (ret); 4633 } 4634 4635 void 4636 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4637 { 4638 RtldLockState lockstate; 4639 4640 wlock_acquire(rtld_bind_lock, &lockstate); 4641 free_tls(tcb, tcbsize, tcbalign); 4642 lock_release(rtld_bind_lock, &lockstate); 4643 } 4644 4645 static void 4646 object_add_name(Obj_Entry *obj, const char *name) 4647 { 4648 Name_Entry *entry; 4649 size_t len; 4650 4651 len = strlen(name); 4652 entry = malloc(sizeof(Name_Entry) + len); 4653 4654 if (entry != NULL) { 4655 strcpy(entry->name, name); 4656 STAILQ_INSERT_TAIL(&obj->names, entry, link); 4657 } 4658 } 4659 4660 static int 4661 object_match_name(const Obj_Entry *obj, const char *name) 4662 { 4663 Name_Entry *entry; 4664 4665 STAILQ_FOREACH(entry, &obj->names, link) { 4666 if (strcmp(name, entry->name) == 0) 4667 return (1); 4668 } 4669 return (0); 4670 } 4671 4672 static Obj_Entry * 4673 locate_dependency(const Obj_Entry *obj, const char *name) 4674 { 4675 const Objlist_Entry *entry; 4676 const Needed_Entry *needed; 4677 4678 STAILQ_FOREACH(entry, &list_main, link) { 4679 if (object_match_name(entry->obj, name)) 4680 return entry->obj; 4681 } 4682 4683 for (needed = obj->needed; needed != NULL; needed = needed->next) { 4684 if (strcmp(obj->strtab + needed->name, name) == 0 || 4685 (needed->obj != NULL && object_match_name(needed->obj, name))) { 4686 /* 4687 * If there is DT_NEEDED for the name we are looking for, 4688 * we are all set. Note that object might not be found if 4689 * dependency was not loaded yet, so the function can 4690 * return NULL here. This is expected and handled 4691 * properly by the caller. 4692 */ 4693 return (needed->obj); 4694 } 4695 } 4696 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 4697 obj->path, name); 4698 die(); 4699 } 4700 4701 static int 4702 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 4703 const Elf_Vernaux *vna) 4704 { 4705 const Elf_Verdef *vd; 4706 const char *vername; 4707 4708 vername = refobj->strtab + vna->vna_name; 4709 vd = depobj->verdef; 4710 if (vd == NULL) { 4711 _rtld_error("%s: version %s required by %s not defined", 4712 depobj->path, vername, refobj->path); 4713 return (-1); 4714 } 4715 for (;;) { 4716 if (vd->vd_version != VER_DEF_CURRENT) { 4717 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4718 depobj->path, vd->vd_version); 4719 return (-1); 4720 } 4721 if (vna->vna_hash == vd->vd_hash) { 4722 const Elf_Verdaux *aux = (const Elf_Verdaux *) 4723 ((char *)vd + vd->vd_aux); 4724 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 4725 return (0); 4726 } 4727 if (vd->vd_next == 0) 4728 break; 4729 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4730 } 4731 if (vna->vna_flags & VER_FLG_WEAK) 4732 return (0); 4733 _rtld_error("%s: version %s required by %s not found", 4734 depobj->path, vername, refobj->path); 4735 return (-1); 4736 } 4737 4738 static int 4739 rtld_verify_object_versions(Obj_Entry *obj) 4740 { 4741 const Elf_Verneed *vn; 4742 const Elf_Verdef *vd; 4743 const Elf_Verdaux *vda; 4744 const Elf_Vernaux *vna; 4745 const Obj_Entry *depobj; 4746 int maxvernum, vernum; 4747 4748 if (obj->ver_checked) 4749 return (0); 4750 obj->ver_checked = true; 4751 4752 maxvernum = 0; 4753 /* 4754 * Walk over defined and required version records and figure out 4755 * max index used by any of them. Do very basic sanity checking 4756 * while there. 4757 */ 4758 vn = obj->verneed; 4759 while (vn != NULL) { 4760 if (vn->vn_version != VER_NEED_CURRENT) { 4761 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 4762 obj->path, vn->vn_version); 4763 return (-1); 4764 } 4765 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4766 for (;;) { 4767 vernum = VER_NEED_IDX(vna->vna_other); 4768 if (vernum > maxvernum) 4769 maxvernum = vernum; 4770 if (vna->vna_next == 0) 4771 break; 4772 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4773 } 4774 if (vn->vn_next == 0) 4775 break; 4776 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4777 } 4778 4779 vd = obj->verdef; 4780 while (vd != NULL) { 4781 if (vd->vd_version != VER_DEF_CURRENT) { 4782 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4783 obj->path, vd->vd_version); 4784 return (-1); 4785 } 4786 vernum = VER_DEF_IDX(vd->vd_ndx); 4787 if (vernum > maxvernum) 4788 maxvernum = vernum; 4789 if (vd->vd_next == 0) 4790 break; 4791 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4792 } 4793 4794 if (maxvernum == 0) 4795 return (0); 4796 4797 /* 4798 * Store version information in array indexable by version index. 4799 * Verify that object version requirements are satisfied along the 4800 * way. 4801 */ 4802 obj->vernum = maxvernum + 1; 4803 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 4804 4805 vd = obj->verdef; 4806 while (vd != NULL) { 4807 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 4808 vernum = VER_DEF_IDX(vd->vd_ndx); 4809 assert(vernum <= maxvernum); 4810 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 4811 obj->vertab[vernum].hash = vd->vd_hash; 4812 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 4813 obj->vertab[vernum].file = NULL; 4814 obj->vertab[vernum].flags = 0; 4815 } 4816 if (vd->vd_next == 0) 4817 break; 4818 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4819 } 4820 4821 vn = obj->verneed; 4822 while (vn != NULL) { 4823 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 4824 if (depobj == NULL) 4825 return (-1); 4826 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4827 for (;;) { 4828 if (check_object_provided_version(obj, depobj, vna)) 4829 return (-1); 4830 vernum = VER_NEED_IDX(vna->vna_other); 4831 assert(vernum <= maxvernum); 4832 obj->vertab[vernum].hash = vna->vna_hash; 4833 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 4834 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 4835 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 4836 VER_INFO_HIDDEN : 0; 4837 if (vna->vna_next == 0) 4838 break; 4839 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4840 } 4841 if (vn->vn_next == 0) 4842 break; 4843 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4844 } 4845 return 0; 4846 } 4847 4848 static int 4849 rtld_verify_versions(const Objlist *objlist) 4850 { 4851 Objlist_Entry *entry; 4852 int rc; 4853 4854 rc = 0; 4855 STAILQ_FOREACH(entry, objlist, link) { 4856 /* 4857 * Skip dummy objects or objects that have their version requirements 4858 * already checked. 4859 */ 4860 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 4861 continue; 4862 if (rtld_verify_object_versions(entry->obj) == -1) { 4863 rc = -1; 4864 if (ld_tracing == NULL) 4865 break; 4866 } 4867 } 4868 if (rc == 0 || ld_tracing != NULL) 4869 rc = rtld_verify_object_versions(&obj_rtld); 4870 return rc; 4871 } 4872 4873 const Ver_Entry * 4874 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 4875 { 4876 Elf_Versym vernum; 4877 4878 if (obj->vertab) { 4879 vernum = VER_NDX(obj->versyms[symnum]); 4880 if (vernum >= obj->vernum) { 4881 _rtld_error("%s: symbol %s has wrong verneed value %d", 4882 obj->path, obj->strtab + symnum, vernum); 4883 } else if (obj->vertab[vernum].hash != 0) { 4884 return &obj->vertab[vernum]; 4885 } 4886 } 4887 return NULL; 4888 } 4889 4890 int 4891 _rtld_get_stack_prot(void) 4892 { 4893 4894 return (stack_prot); 4895 } 4896 4897 int 4898 _rtld_is_dlopened(void *arg) 4899 { 4900 Obj_Entry *obj; 4901 RtldLockState lockstate; 4902 int res; 4903 4904 rlock_acquire(rtld_bind_lock, &lockstate); 4905 obj = dlcheck(arg); 4906 if (obj == NULL) 4907 obj = obj_from_addr(arg); 4908 if (obj == NULL) { 4909 _rtld_error("No shared object contains address"); 4910 lock_release(rtld_bind_lock, &lockstate); 4911 return (-1); 4912 } 4913 res = obj->dlopened ? 1 : 0; 4914 lock_release(rtld_bind_lock, &lockstate); 4915 return (res); 4916 } 4917 4918 static void 4919 map_stacks_exec(RtldLockState *lockstate) 4920 { 4921 void (*thr_map_stacks_exec)(void); 4922 4923 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 4924 return; 4925 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 4926 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 4927 if (thr_map_stacks_exec != NULL) { 4928 stack_prot |= PROT_EXEC; 4929 thr_map_stacks_exec(); 4930 } 4931 } 4932 4933 void 4934 symlook_init(SymLook *dst, const char *name) 4935 { 4936 4937 bzero(dst, sizeof(*dst)); 4938 dst->name = name; 4939 dst->hash = elf_hash(name); 4940 dst->hash_gnu = gnu_hash(name); 4941 } 4942 4943 static void 4944 symlook_init_from_req(SymLook *dst, const SymLook *src) 4945 { 4946 4947 dst->name = src->name; 4948 dst->hash = src->hash; 4949 dst->hash_gnu = src->hash_gnu; 4950 dst->ventry = src->ventry; 4951 dst->flags = src->flags; 4952 dst->defobj_out = NULL; 4953 dst->sym_out = NULL; 4954 dst->lockstate = src->lockstate; 4955 } 4956 4957 4958 /* 4959 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 4960 */ 4961 static int 4962 parse_libdir(const char *str) 4963 { 4964 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 4965 const char *orig; 4966 int fd; 4967 char c; 4968 4969 orig = str; 4970 fd = 0; 4971 for (c = *str; c != '\0'; c = *++str) { 4972 if (c < '0' || c > '9') 4973 return (-1); 4974 4975 fd *= RADIX; 4976 fd += c - '0'; 4977 } 4978 4979 /* Make sure we actually parsed something. */ 4980 if (str == orig) { 4981 _rtld_error("failed to parse directory FD from '%s'", str); 4982 return (-1); 4983 } 4984 return (fd); 4985 } 4986 4987 /* 4988 * Overrides for libc_pic-provided functions. 4989 */ 4990 4991 int 4992 __getosreldate(void) 4993 { 4994 size_t len; 4995 int oid[2]; 4996 int error, osrel; 4997 4998 if (osreldate != 0) 4999 return (osreldate); 5000 5001 oid[0] = CTL_KERN; 5002 oid[1] = KERN_OSRELDATE; 5003 osrel = 0; 5004 len = sizeof(osrel); 5005 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 5006 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 5007 osreldate = osrel; 5008 return (osreldate); 5009 } 5010 5011 void 5012 exit(int status) 5013 { 5014 5015 _exit(status); 5016 } 5017 5018 void (*__cleanup)(void); 5019 int __isthreaded = 0; 5020 int _thread_autoinit_dummy_decl = 1; 5021 5022 /* 5023 * No unresolved symbols for rtld. 5024 */ 5025 void 5026 __pthread_cxa_finalize(struct dl_phdr_info *a) 5027 { 5028 } 5029 5030 void 5031 __stack_chk_fail(void) 5032 { 5033 5034 _rtld_error("stack overflow detected; terminated"); 5035 die(); 5036 } 5037 __weak_reference(__stack_chk_fail, __stack_chk_fail_local); 5038 5039 void 5040 __chk_fail(void) 5041 { 5042 5043 _rtld_error("buffer overflow detected; terminated"); 5044 die(); 5045 } 5046 5047 const char * 5048 rtld_strerror(int errnum) 5049 { 5050 5051 if (errnum < 0 || errnum >= sys_nerr) 5052 return ("Unknown error"); 5053 return (sys_errlist[errnum]); 5054 } 5055