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 #include <sys/resident.h> 50 #include <sys/tls.h> 51 52 #include <machine/tls.h> 53 54 #include <dlfcn.h> 55 #include <err.h> 56 #include <errno.h> 57 #include <fcntl.h> 58 #include <stdarg.h> 59 #include <stdio.h> 60 #include <stdlib.h> 61 #include <string.h> 62 #include <unistd.h> 63 64 #include "debug.h" 65 #include "rtld.h" 66 #include "libmap.h" 67 #include "rtld_printf.h" 68 #include "notes.h" 69 70 #define PATH_RTLD "/usr/libexec/ld-elf.so.2" 71 #define LD_ARY_CACHE 16 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 *_getenv_ld(const char *id); 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 *); 98 static const char *gethints(bool); 99 static void init_dag(Obj_Entry *); 100 static void init_rtld(caddr_t, Elf_Auxinfo **); 101 static void initlist_add_neededs(Needed_Entry *, Objlist *); 102 static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *); 103 static void linkmap_add(Obj_Entry *); 104 static void linkmap_delete(Obj_Entry *); 105 static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 106 static void unload_filtees(Obj_Entry *); 107 static int load_needed_objects(Obj_Entry *, int); 108 static int load_preload_objects(void); 109 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 110 static void map_stacks_exec(RtldLockState *); 111 static Obj_Entry *obj_from_addr(const void *); 112 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 113 static void objlist_call_init(Objlist *, RtldLockState *); 114 static void objlist_clear(Objlist *); 115 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 116 static void objlist_init(Objlist *); 117 static void objlist_push_head(Objlist *, Obj_Entry *); 118 static void objlist_push_tail(Objlist *, Obj_Entry *); 119 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 120 static void objlist_remove(Objlist *, Obj_Entry *); 121 static void *path_enumerate(const char *, path_enum_proc, void *); 122 static int relocate_object_dag(Obj_Entry *root, bool bind_now, 123 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 124 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 125 int flags, RtldLockState *lockstate); 126 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 127 RtldLockState *); 128 static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now, 129 int flags, RtldLockState *lockstate); 130 static int rtld_dirname(const char *, char *); 131 static int rtld_dirname_abs(const char *, char *); 132 static void *rtld_dlopen(const char *name, int fd, int mode); 133 static void rtld_exit(void); 134 static char *search_library_path(const char *, const char *); 135 static const void **get_program_var_addr(const char *, RtldLockState *); 136 static void set_program_var(const char *, const void *); 137 static int symlook_default(SymLook *, const Obj_Entry *refobj); 138 static int symlook_global(SymLook *, DoneList *); 139 static void symlook_init_from_req(SymLook *, const SymLook *); 140 static int symlook_list(SymLook *, const Objlist *, DoneList *); 141 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 142 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 143 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 144 static void trace_loaded_objects(Obj_Entry *); 145 static void unlink_object(Obj_Entry *); 146 static void unload_object(Obj_Entry *); 147 static void unref_dag(Obj_Entry *); 148 static void ref_dag(Obj_Entry *); 149 static char *origin_subst_one(char *, const char *, const char *, bool); 150 static char *origin_subst(char *, const char *); 151 static void preinit_main(void); 152 static int rtld_verify_versions(const Objlist *); 153 static int rtld_verify_object_versions(Obj_Entry *); 154 static void object_add_name(Obj_Entry *, const char *); 155 static int object_match_name(const Obj_Entry *, const char *); 156 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 157 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 158 struct dl_phdr_info *phdr_info); 159 static uint_fast32_t gnu_hash (const char *); 160 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 161 const unsigned long); 162 163 void r_debug_state(struct r_debug *, struct link_map *) __noinline; 164 165 /* 166 * Data declarations. 167 */ 168 static char *error_message; /* Message for dlerror(), or NULL */ 169 struct r_debug r_debug; /* for GDB; */ 170 static bool libmap_disable; /* Disable libmap */ 171 static bool ld_loadfltr; /* Immediate filters processing */ 172 static char *libmap_override; /* Maps to use in addition to libmap.conf */ 173 static bool trust; /* False for setuid and setgid programs */ 174 static bool dangerous_ld_env; /* True if environment variables have been 175 used to affect the libraries loaded */ 176 static const char *ld_bind_now; /* Environment variable for immediate binding */ 177 static const char *ld_debug; /* Environment variable for debugging */ 178 static const char *ld_library_path; /* Environment variable for search path */ 179 static char *ld_preload; /* Environment variable for libraries to 180 load first */ 181 static const char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 182 static const char *ld_tracing; /* Called from ldd to print libs */ 183 static const char *ld_utrace; /* Use utrace() to log events. */ 184 static int (*rtld_functrace)( /* Optional function call tracing hook */ 185 const char *caller_obj, 186 const char *callee_obj, 187 const char *callee_func, 188 void *stack); 189 static const Obj_Entry *rtld_functrace_obj; /* Object thereof */ 190 static Obj_Entry *obj_list; /* Head of linked list of shared objects */ 191 static Obj_Entry **obj_tail; /* Link field of last object in list */ 192 static Obj_Entry **preload_tail; 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 int ld_resident; /* Non-zero if resident */ 199 static const char *ld_ary[LD_ARY_CACHE]; 200 static int ld_index; 201 static Objlist initlist; 202 203 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 204 STAILQ_HEAD_INITIALIZER(list_global); 205 static Objlist list_main = /* Objects loaded at program startup */ 206 STAILQ_HEAD_INITIALIZER(list_main); 207 static Objlist list_fini = /* Objects needing fini() calls */ 208 STAILQ_HEAD_INITIALIZER(list_fini); 209 210 static Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 211 const char *__ld_sharedlib_base; 212 213 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 214 215 extern Elf_Dyn _DYNAMIC; 216 #pragma weak _DYNAMIC 217 #ifndef RTLD_IS_DYNAMIC 218 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL) 219 #endif 220 221 #ifdef ENABLE_OSRELDATE 222 int osreldate; 223 #endif 224 225 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 226 static int max_stack_flags; 227 228 /* 229 * Global declarations normally provided by crt1. The dynamic linker is 230 * not built with crt1, so we have to provide them ourselves. 231 */ 232 char *__progname; 233 char **environ; 234 235 /* 236 * Used to pass argc, argv to init functions. 237 */ 238 int main_argc; 239 char **main_argv; 240 241 /* 242 * Globals to control TLS allocation. 243 */ 244 size_t tls_last_offset; /* Static TLS offset of last module */ 245 size_t tls_last_size; /* Static TLS size of last module */ 246 size_t tls_static_space; /* Static TLS space allocated */ 247 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 248 int tls_max_index = 1; /* Largest module index allocated */ 249 250 /* 251 * Fill in a DoneList with an allocation large enough to hold all of 252 * the currently-loaded objects. Keep this as a macro since it calls 253 * alloca and we want that to occur within the scope of the caller. 254 */ 255 #define donelist_init(dlp) \ 256 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 257 assert((dlp)->objs != NULL), \ 258 (dlp)->num_alloc = obj_count, \ 259 (dlp)->num_used = 0) 260 261 #define UTRACE_DLOPEN_START 1 262 #define UTRACE_DLOPEN_STOP 2 263 #define UTRACE_DLCLOSE_START 3 264 #define UTRACE_DLCLOSE_STOP 4 265 #define UTRACE_LOAD_OBJECT 5 266 #define UTRACE_UNLOAD_OBJECT 6 267 #define UTRACE_ADD_RUNDEP 7 268 #define UTRACE_PRELOAD_FINISHED 8 269 #define UTRACE_INIT_CALL 9 270 #define UTRACE_FINI_CALL 10 271 272 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 Obj_Entry *last_interposer; 328 Elf_Auxinfo *aux_info[AT_COUNT]; 329 int i; 330 int argc; 331 char **argv; 332 char **env; 333 Elf_Auxinfo *aux; 334 Elf_Auxinfo *auxp; 335 const char *argv0; 336 Objlist_Entry *entry; 337 Obj_Entry *obj; 338 339 /* marino: DO NOT MOVE THESE VARIABLES TO _rtld 340 Obj_Entry **preload_tail; 341 Objlist initlist; 342 from global to here. It will break the DWARF2 unwind scheme. 343 The system compilers were unaffected, but not gcc 4.6 344 */ 345 346 /* 347 * On entry, the dynamic linker itself has not been relocated yet. 348 * Be very careful not to reference any global data until after 349 * init_rtld has returned. It is OK to reference file-scope statics 350 * and string constants, and to call static and global functions. 351 */ 352 353 /* Find the auxiliary vector on the stack. */ 354 argc = *sp++; 355 argv = (char **) sp; 356 sp += argc + 1; /* Skip over arguments and NULL terminator */ 357 env = (char **) sp; 358 359 /* 360 * If we aren't already resident we have to dig out some more info. 361 * Note that auxinfo does not exist when we are resident. 362 * 363 * I'm not sure about the ld_resident check. It seems to read zero 364 * prior to relocation, which is what we want. When running from a 365 * resident copy everything will be relocated so we are definitely 366 * good there. 367 */ 368 if (ld_resident == 0) { 369 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 370 ; 371 aux = (Elf_Auxinfo *) sp; 372 373 /* Digest the auxiliary vector. */ 374 for (i = 0; i < AT_COUNT; i++) 375 aux_info[i] = NULL; 376 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 377 if (auxp->a_type < AT_COUNT) 378 aux_info[auxp->a_type] = auxp; 379 } 380 381 /* Initialize and relocate ourselves. */ 382 assert(aux_info[AT_BASE] != NULL); 383 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 384 } 385 386 ld_index = 0; /* don't use old env cache in case we are resident */ 387 __progname = obj_rtld.path; 388 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 389 environ = env; 390 main_argc = argc; 391 main_argv = argv; 392 393 trust = !issetugid(); 394 395 ld_bind_now = _getenv_ld("LD_BIND_NOW"); 396 /* 397 * If the process is tainted, then we un-set the dangerous environment 398 * variables. The process will be marked as tainted until setuid(2) 399 * is called. If any child process calls setuid(2) we do not want any 400 * future processes to honor the potentially un-safe variables. 401 */ 402 if (!trust) { 403 if ( unsetenv("LD_DEBUG") 404 || unsetenv("LD_PRELOAD") 405 || unsetenv("LD_LIBRARY_PATH") 406 || unsetenv("LD_ELF_HINTS_PATH") 407 || unsetenv("LD_LIBMAP") 408 || unsetenv("LD_LIBMAP_DISABLE") 409 || unsetenv("LD_LOADFLTR") 410 || unsetenv("LD_SHAREDLIB_BASE") 411 ) { 412 _rtld_error("environment corrupt; aborting"); 413 die(); 414 } 415 } 416 __ld_sharedlib_base = _getenv_ld("LD_SHAREDLIB_BASE"); 417 ld_debug = _getenv_ld("LD_DEBUG"); 418 libmap_disable = _getenv_ld("LD_LIBMAP_DISABLE") != NULL; 419 libmap_override = (char *)_getenv_ld("LD_LIBMAP"); 420 ld_library_path = _getenv_ld("LD_LIBRARY_PATH"); 421 ld_preload = (char *)_getenv_ld("LD_PRELOAD"); 422 ld_elf_hints_path = _getenv_ld("LD_ELF_HINTS_PATH"); 423 ld_loadfltr = _getenv_ld("LD_LOADFLTR") != NULL; 424 dangerous_ld_env = (ld_library_path != NULL) 425 || (ld_preload != NULL) 426 || (ld_elf_hints_path != NULL) 427 || ld_loadfltr 428 || (libmap_override != NULL) 429 || libmap_disable 430 ; 431 ld_tracing = _getenv_ld("LD_TRACE_LOADED_OBJECTS"); 432 ld_utrace = _getenv_ld("LD_UTRACE"); 433 434 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 435 ld_elf_hints_path = _PATH_ELF_HINTS; 436 437 if (ld_debug != NULL && *ld_debug != '\0') 438 debug = 1; 439 dbg("%s is initialized, base address = %p", __progname, 440 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 441 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 442 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 443 444 dbg("initializing thread locks"); 445 lockdflt_init(); 446 447 /* 448 * If we are resident we can skip work that we have already done. 449 * Note that the stack is reset and there is no Elf_Auxinfo 450 * when running from a resident image, and the static globals setup 451 * between here and resident_skip will have already been setup. 452 */ 453 if (ld_resident) 454 goto resident_skip1; 455 456 /* 457 * Load the main program, or process its program header if it is 458 * already loaded. 459 */ 460 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */ 461 int fd = aux_info[AT_EXECFD]->a_un.a_val; 462 dbg("loading main program"); 463 obj_main = map_object(fd, argv0, NULL); 464 close(fd); 465 if (obj_main == NULL) 466 die(); 467 max_stack_flags = obj->stack_flags; 468 } else { /* Main program already loaded. */ 469 const Elf_Phdr *phdr; 470 int phnum; 471 caddr_t entry; 472 473 dbg("processing main program's program header"); 474 assert(aux_info[AT_PHDR] != NULL); 475 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 476 assert(aux_info[AT_PHNUM] != NULL); 477 phnum = aux_info[AT_PHNUM]->a_un.a_val; 478 assert(aux_info[AT_PHENT] != NULL); 479 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 480 assert(aux_info[AT_ENTRY] != NULL); 481 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 482 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL) 483 die(); 484 } 485 486 char buf[MAXPATHLEN]; 487 if (aux_info[AT_EXECPATH] != NULL) { 488 char *kexecpath; 489 490 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 491 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 492 if (kexecpath[0] == '/') 493 obj_main->path = kexecpath; 494 else if (getcwd(buf, sizeof(buf)) == NULL || 495 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 496 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 497 obj_main->path = xstrdup(argv0); 498 else 499 obj_main->path = xstrdup(buf); 500 } else { 501 char resolved[MAXPATHLEN]; 502 dbg("No AT_EXECPATH"); 503 if (argv0[0] == '/') { 504 if (realpath(argv0, resolved) != NULL) 505 obj_main->path = xstrdup(resolved); 506 else 507 obj_main->path = xstrdup(argv0); 508 } else { 509 if (getcwd(buf, sizeof(buf)) != NULL 510 && strlcat(buf, "/", sizeof(buf)) < sizeof(buf) 511 && strlcat(buf, argv0, sizeof (buf)) < sizeof(buf) 512 && access(buf, R_OK) == 0 513 && realpath(buf, resolved) != NULL) 514 obj_main->path = xstrdup(resolved); 515 else 516 obj_main->path = xstrdup(argv0); 517 } 518 } 519 dbg("obj_main path %s", obj_main->path); 520 obj_main->mainprog = true; 521 522 if (aux_info[AT_STACKPROT] != NULL && 523 aux_info[AT_STACKPROT]->a_un.a_val != 0) 524 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 525 526 /* 527 * Get the actual dynamic linker pathname from the executable if 528 * possible. (It should always be possible.) That ensures that 529 * gdb will find the right dynamic linker even if a non-standard 530 * one is being used. 531 */ 532 if (obj_main->interp != NULL && 533 strcmp(obj_main->interp, obj_rtld.path) != 0) { 534 free(obj_rtld.path); 535 obj_rtld.path = xstrdup(obj_main->interp); 536 __progname = obj_rtld.path; 537 } 538 539 digest_dynamic(obj_main, 0); 540 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 541 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 542 obj_main->dynsymcount); 543 544 linkmap_add(obj_main); 545 linkmap_add(&obj_rtld); 546 547 /* Link the main program into the list of objects. */ 548 *obj_tail = obj_main; 549 obj_tail = &obj_main->next; 550 obj_count++; 551 obj_loads++; 552 553 /* Initialize a fake symbol for resolving undefined weak references. */ 554 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 555 sym_zero.st_shndx = SHN_UNDEF; 556 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 557 558 if (!libmap_disable) 559 libmap_disable = (bool)lm_init(libmap_override); 560 561 dbg("loading LD_PRELOAD libraries"); 562 if (load_preload_objects() == -1) 563 die(); 564 preload_tail = obj_tail; 565 566 dbg("loading needed objects"); 567 if (load_needed_objects(obj_main, 0) == -1) 568 die(); 569 570 /* Make a list of all objects loaded at startup. */ 571 last_interposer = obj_main; 572 for (obj = obj_list; obj != NULL; obj = obj->next) { 573 if (obj->z_interpose && obj != obj_main) { 574 objlist_put_after(&list_main, last_interposer, obj); 575 last_interposer = obj; 576 } else { 577 objlist_push_tail(&list_main, obj); 578 } 579 obj->refcount++; 580 } 581 582 dbg("checking for required versions"); 583 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 584 die(); 585 586 resident_skip1: 587 588 if (ld_tracing) { /* We're done */ 589 trace_loaded_objects(obj_main); 590 exit(0); 591 } 592 593 if (ld_resident) /* XXX clean this up! */ 594 goto resident_skip2; 595 596 if (_getenv_ld("LD_DUMP_REL_PRE") != NULL) { 597 dump_relocations(obj_main); 598 exit (0); 599 } 600 601 /* setup TLS for main thread */ 602 dbg("initializing initial thread local storage"); 603 STAILQ_FOREACH(entry, &list_main, link) { 604 /* 605 * Allocate all the initial objects out of the static TLS 606 * block even if they didn't ask for it. 607 */ 608 allocate_tls_offset(entry->obj); 609 } 610 611 tls_static_space = tls_last_offset + RTLD_STATIC_TLS_EXTRA; 612 613 /* 614 * Do not try to allocate the TLS here, let libc do it itself. 615 * (crt1 for the program will call _init_tls()) 616 */ 617 618 if (relocate_objects(obj_main, 619 ld_bind_now != NULL && *ld_bind_now != '\0', 620 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 621 die(); 622 623 dbg("doing copy relocations"); 624 if (do_copy_relocations(obj_main) == -1) 625 die(); 626 627 resident_skip2: 628 629 if (_getenv_ld("LD_RESIDENT_UNREGISTER_NOW")) { 630 if (exec_sys_unregister(-1) < 0) { 631 dbg("exec_sys_unregister failed %d\n", errno); 632 exit(errno); 633 } 634 dbg("exec_sys_unregister success\n"); 635 exit(0); 636 } 637 638 if (_getenv_ld("LD_DUMP_REL_POST") != NULL) { 639 dump_relocations(obj_main); 640 exit (0); 641 } 642 643 dbg("initializing key program variables"); 644 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 645 set_program_var("environ", env); 646 set_program_var("__elf_aux_vector", aux); 647 648 if (_getenv_ld("LD_RESIDENT_REGISTER_NOW")) { 649 extern void resident_start(void); 650 ld_resident = 1; 651 if (exec_sys_register(resident_start) < 0) { 652 dbg("exec_sys_register failed %d\n", errno); 653 exit(errno); 654 } 655 dbg("exec_sys_register success\n"); 656 exit(0); 657 } 658 659 /* Make a list of init functions to call. */ 660 objlist_init(&initlist); 661 initlist_add_objects(obj_list, preload_tail, &initlist); 662 663 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 664 665 map_stacks_exec(NULL); 666 667 dbg("resolving ifuncs"); 668 if (resolve_objects_ifunc(obj_main, 669 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY, 670 NULL) == -1) 671 die(); 672 673 /* 674 * Do NOT call the initlist here, give libc a chance to set up 675 * the initial TLS segment. crt1 will then call _rtld_call_init(). 676 */ 677 678 dbg("transferring control to program entry point = %p", obj_main->entry); 679 680 /* Return the exit procedure and the program entry point. */ 681 *exit_proc = rtld_exit; 682 *objp = obj_main; 683 return (func_ptr_type) obj_main->entry; 684 } 685 686 /* 687 * Call the initialization list for dynamically loaded libraries. 688 * (called from crt1.c). 689 */ 690 void 691 _rtld_call_init(void) 692 { 693 RtldLockState lockstate; 694 Obj_Entry *obj; 695 696 if (!obj_main->note_present && obj_main->valid_hash_gnu) { 697 /* 698 * The use of a linker script with a PHDRS directive that does not include 699 * PT_NOTE will block the crt_no_init note. In this case we'll look for the 700 * recently added GNU hash dynamic tag which gets built by default. It is 701 * extremely unlikely to find a pre-3.1 binary without a PT_NOTE header and 702 * a gnu hash tag. If gnu hash found, consider binary to use new crt code. 703 */ 704 obj_main->crt_no_init = true; 705 dbg("Setting crt_no_init without presence of PT_NOTE header"); 706 } 707 708 wlock_acquire(rtld_bind_lock, &lockstate); 709 if (obj_main->crt_no_init) 710 preinit_main(); 711 else { 712 /* 713 * Make sure we don't call the main program's init and fini functions 714 * for binaries linked with old crt1 which calls _init itself. 715 */ 716 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 717 obj_main->init_array = obj_main->fini_array = (Elf_Addr)NULL; 718 } 719 objlist_call_init(&initlist, &lockstate); 720 objlist_clear(&initlist); 721 dbg("loading filtees"); 722 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 723 if (ld_loadfltr || obj->z_loadfltr) 724 load_filtees(obj, 0, &lockstate); 725 } 726 lock_release(rtld_bind_lock, &lockstate); 727 } 728 729 void * 730 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 731 { 732 void *ptr; 733 Elf_Addr target; 734 735 ptr = (void *)make_function_pointer(def, obj); 736 target = ((Elf_Addr (*)(void))ptr)(); 737 return ((void *)target); 738 } 739 740 Elf_Addr 741 _rtld_bind(Obj_Entry *obj, Elf_Size reloff, void *stack) 742 { 743 const Elf_Rel *rel; 744 const Elf_Sym *def; 745 const Obj_Entry *defobj; 746 Elf_Addr *where; 747 Elf_Addr target; 748 RtldLockState lockstate; 749 750 rlock_acquire(rtld_bind_lock, &lockstate); 751 if (sigsetjmp(lockstate.env, 0) != 0) 752 lock_upgrade(rtld_bind_lock, &lockstate); 753 if (obj->pltrel) 754 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 755 else 756 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 757 758 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 759 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL, 760 &lockstate); 761 if (def == NULL) 762 die(); 763 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 764 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 765 else 766 target = (Elf_Addr)(defobj->relocbase + def->st_value); 767 768 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 769 defobj->strtab + def->st_name, basename(obj->path), 770 (void *)target, basename(defobj->path)); 771 772 /* 773 * If we have a function call tracing hook, and the 774 * hook would like to keep tracing this one function, 775 * prevent the relocation so we will wind up here 776 * the next time again. 777 * 778 * We don't want to functrace calls from the functracer 779 * to avoid recursive loops. 780 */ 781 if (rtld_functrace != NULL && obj != rtld_functrace_obj) { 782 if (rtld_functrace(obj->path, 783 defobj->path, 784 defobj->strtab + def->st_name, 785 stack)) { 786 lock_release(rtld_bind_lock, &lockstate); 787 return target; 788 } 789 } 790 791 /* 792 * Write the new contents for the jmpslot. Note that depending on 793 * architecture, the value which we need to return back to the 794 * lazy binding trampoline may or may not be the target 795 * address. The value returned from reloc_jmpslot() is the value 796 * that the trampoline needs. 797 */ 798 target = reloc_jmpslot(where, target, defobj, obj, rel); 799 lock_release(rtld_bind_lock, &lockstate); 800 return target; 801 } 802 803 /* 804 * Error reporting function. Use it like printf. If formats the message 805 * into a buffer, and sets things up so that the next call to dlerror() 806 * will return the message. 807 */ 808 void 809 _rtld_error(const char *fmt, ...) 810 { 811 static char buf[512]; 812 va_list ap; 813 814 va_start(ap, fmt); 815 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 816 error_message = buf; 817 va_end(ap); 818 } 819 820 /* 821 * Return a dynamically-allocated copy of the current error message, if any. 822 */ 823 static char * 824 errmsg_save(void) 825 { 826 return error_message == NULL ? NULL : xstrdup(error_message); 827 } 828 829 /* 830 * Restore the current error message from a copy which was previously saved 831 * by errmsg_save(). The copy is freed. 832 */ 833 static void 834 errmsg_restore(char *saved_msg) 835 { 836 if (saved_msg == NULL) 837 error_message = NULL; 838 else { 839 _rtld_error("%s", saved_msg); 840 free(saved_msg); 841 } 842 } 843 844 const char * 845 basename(const char *name) 846 { 847 const char *p = strrchr(name, '/'); 848 return p != NULL ? p + 1 : name; 849 } 850 851 static struct utsname uts; 852 853 static char * 854 origin_subst_one(char *real, const char *kw, const char *subst, 855 bool may_free) 856 { 857 char *p, *p1, *res, *resp; 858 int subst_len, kw_len, subst_count, old_len, new_len; 859 860 kw_len = strlen(kw); 861 862 /* 863 * First, count the number of the keyword occurences, to 864 * preallocate the final string. 865 */ 866 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 867 p1 = strstr(p, kw); 868 if (p1 == NULL) 869 break; 870 } 871 872 /* 873 * If the keyword is not found, just return. 874 */ 875 if (subst_count == 0) 876 return (may_free ? real : xstrdup(real)); 877 878 /* 879 * There is indeed something to substitute. Calculate the 880 * length of the resulting string, and allocate it. 881 */ 882 subst_len = strlen(subst); 883 old_len = strlen(real); 884 new_len = old_len + (subst_len - kw_len) * subst_count; 885 res = xmalloc(new_len + 1); 886 887 /* 888 * Now, execute the substitution loop. 889 */ 890 for (p = real, resp = res, *resp = '\0';;) { 891 p1 = strstr(p, kw); 892 if (p1 != NULL) { 893 /* Copy the prefix before keyword. */ 894 memcpy(resp, p, p1 - p); 895 resp += p1 - p; 896 /* Keyword replacement. */ 897 memcpy(resp, subst, subst_len); 898 resp += subst_len; 899 *resp = '\0'; 900 p = p1 + kw_len; 901 } else 902 break; 903 } 904 905 /* Copy to the end of string and finish. */ 906 strcat(resp, p); 907 if (may_free) 908 free(real); 909 return (res); 910 } 911 912 static char * 913 origin_subst(char *real, const char *origin_path) 914 { 915 char *res1, *res2, *res3, *res4; 916 917 if (uts.sysname[0] == '\0') { 918 if (uname(&uts) != 0) { 919 _rtld_error("utsname failed: %d", errno); 920 return (NULL); 921 } 922 } 923 res1 = origin_subst_one(real, "$ORIGIN", origin_path, false); 924 res2 = origin_subst_one(res1, "$OSNAME", uts.sysname, true); 925 res3 = origin_subst_one(res2, "$OSREL", uts.release, true); 926 res4 = origin_subst_one(res3, "$PLATFORM", uts.machine, true); 927 return (res4); 928 } 929 930 static void 931 die(void) 932 { 933 const char *msg = dlerror(); 934 935 if (msg == NULL) 936 msg = "Fatal error"; 937 rtld_fdputstr(STDERR_FILENO, msg); 938 rtld_fdputchar(STDERR_FILENO, '\n'); 939 _exit(1); 940 } 941 942 /* 943 * Process a shared object's DYNAMIC section, and save the important 944 * information in its Obj_Entry structure. 945 */ 946 static void 947 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 948 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 949 { 950 const Elf_Dyn *dynp; 951 Needed_Entry **needed_tail = &obj->needed; 952 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 953 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 954 const Elf_Hashelt *hashtab; 955 const Elf32_Word *hashval; 956 Elf32_Word bkt, nmaskwords; 957 int bloom_size32; 958 bool nmw_power2; 959 int plttype = DT_REL; 960 961 *dyn_rpath = NULL; 962 *dyn_soname = NULL; 963 *dyn_runpath = NULL; 964 965 obj->bind_now = false; 966 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 967 switch (dynp->d_tag) { 968 969 case DT_REL: 970 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 971 break; 972 973 case DT_RELSZ: 974 obj->relsize = dynp->d_un.d_val; 975 break; 976 977 case DT_RELENT: 978 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 979 break; 980 981 case DT_JMPREL: 982 obj->pltrel = (const Elf_Rel *) 983 (obj->relocbase + dynp->d_un.d_ptr); 984 break; 985 986 case DT_PLTRELSZ: 987 obj->pltrelsize = dynp->d_un.d_val; 988 break; 989 990 case DT_RELA: 991 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 992 break; 993 994 case DT_RELASZ: 995 obj->relasize = dynp->d_un.d_val; 996 break; 997 998 case DT_RELAENT: 999 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 1000 break; 1001 1002 case DT_PLTREL: 1003 plttype = dynp->d_un.d_val; 1004 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 1005 break; 1006 1007 case DT_SYMTAB: 1008 obj->symtab = (const Elf_Sym *) 1009 (obj->relocbase + dynp->d_un.d_ptr); 1010 break; 1011 1012 case DT_SYMENT: 1013 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 1014 break; 1015 1016 case DT_STRTAB: 1017 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 1018 break; 1019 1020 case DT_STRSZ: 1021 obj->strsize = dynp->d_un.d_val; 1022 break; 1023 1024 case DT_VERNEED: 1025 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 1026 dynp->d_un.d_val); 1027 break; 1028 1029 case DT_VERNEEDNUM: 1030 obj->verneednum = dynp->d_un.d_val; 1031 break; 1032 1033 case DT_VERDEF: 1034 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 1035 dynp->d_un.d_val); 1036 break; 1037 1038 case DT_VERDEFNUM: 1039 obj->verdefnum = dynp->d_un.d_val; 1040 break; 1041 1042 case DT_VERSYM: 1043 obj->versyms = (const Elf_Versym *)(obj->relocbase + 1044 dynp->d_un.d_val); 1045 break; 1046 1047 case DT_HASH: 1048 { 1049 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1050 dynp->d_un.d_ptr); 1051 obj->nbuckets = hashtab[0]; 1052 obj->nchains = hashtab[1]; 1053 obj->buckets = hashtab + 2; 1054 obj->chains = obj->buckets + obj->nbuckets; 1055 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 1056 obj->buckets != NULL; 1057 } 1058 break; 1059 1060 case DT_GNU_HASH: 1061 { 1062 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1063 dynp->d_un.d_ptr); 1064 obj->nbuckets_gnu = hashtab[0]; 1065 obj->symndx_gnu = hashtab[1]; 1066 nmaskwords = hashtab[2]; 1067 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1068 /* Number of bitmask words is required to be power of 2 */ 1069 nmw_power2 = ((nmaskwords & (nmaskwords - 1)) == 0); 1070 obj->maskwords_bm_gnu = nmaskwords - 1; 1071 obj->shift2_gnu = hashtab[3]; 1072 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4); 1073 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1074 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1075 obj->symndx_gnu; 1076 obj->valid_hash_gnu = nmw_power2 && obj->nbuckets_gnu > 0 && 1077 obj->buckets_gnu != NULL; 1078 } 1079 break; 1080 1081 case DT_NEEDED: 1082 if (!obj->rtld) { 1083 Needed_Entry *nep = NEW(Needed_Entry); 1084 nep->name = dynp->d_un.d_val; 1085 nep->obj = NULL; 1086 nep->next = NULL; 1087 1088 *needed_tail = nep; 1089 needed_tail = &nep->next; 1090 } 1091 break; 1092 1093 case DT_FILTER: 1094 if (!obj->rtld) { 1095 Needed_Entry *nep = NEW(Needed_Entry); 1096 nep->name = dynp->d_un.d_val; 1097 nep->obj = NULL; 1098 nep->next = NULL; 1099 1100 *needed_filtees_tail = nep; 1101 needed_filtees_tail = &nep->next; 1102 } 1103 break; 1104 1105 case DT_AUXILIARY: 1106 if (!obj->rtld) { 1107 Needed_Entry *nep = NEW(Needed_Entry); 1108 nep->name = dynp->d_un.d_val; 1109 nep->obj = NULL; 1110 nep->next = NULL; 1111 1112 *needed_aux_filtees_tail = nep; 1113 needed_aux_filtees_tail = &nep->next; 1114 } 1115 break; 1116 1117 case DT_PLTGOT: 1118 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 1119 break; 1120 1121 case DT_TEXTREL: 1122 obj->textrel = true; 1123 break; 1124 1125 case DT_SYMBOLIC: 1126 obj->symbolic = true; 1127 break; 1128 1129 case DT_RPATH: 1130 /* 1131 * We have to wait until later to process this, because we 1132 * might not have gotten the address of the string table yet. 1133 */ 1134 *dyn_rpath = dynp; 1135 break; 1136 1137 case DT_SONAME: 1138 *dyn_soname = dynp; 1139 break; 1140 1141 case DT_RUNPATH: 1142 *dyn_runpath = dynp; 1143 break; 1144 1145 case DT_INIT: 1146 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1147 break; 1148 1149 case DT_FINI: 1150 obj->fini = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1151 break; 1152 1153 case DT_PREINIT_ARRAY: 1154 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1155 break; 1156 1157 case DT_INIT_ARRAY: 1158 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1159 break; 1160 1161 case DT_FINI_ARRAY: 1162 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1163 break; 1164 1165 case DT_PREINIT_ARRAYSZ: 1166 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1167 break; 1168 1169 case DT_INIT_ARRAYSZ: 1170 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1171 break; 1172 1173 case DT_FINI_ARRAYSZ: 1174 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1175 break; 1176 1177 case DT_DEBUG: 1178 /* XXX - not implemented yet */ 1179 if (!early) 1180 dbg("Filling in DT_DEBUG entry"); 1181 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 1182 break; 1183 1184 case DT_FLAGS: 1185 if ((dynp->d_un.d_val & DF_ORIGIN) && trust) 1186 obj->z_origin = true; 1187 if (dynp->d_un.d_val & DF_SYMBOLIC) 1188 obj->symbolic = true; 1189 if (dynp->d_un.d_val & DF_TEXTREL) 1190 obj->textrel = true; 1191 if (dynp->d_un.d_val & DF_BIND_NOW) 1192 obj->bind_now = true; 1193 /*if (dynp->d_un.d_val & DF_STATIC_TLS) 1194 ;*/ 1195 break; 1196 1197 case DT_FLAGS_1: 1198 if (dynp->d_un.d_val & DF_1_NOOPEN) 1199 obj->z_noopen = true; 1200 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust) 1201 obj->z_origin = true; 1202 /*if (dynp->d_un.d_val & DF_1_GLOBAL) 1203 XXX ;*/ 1204 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1205 obj->bind_now = true; 1206 if (dynp->d_un.d_val & DF_1_NODELETE) 1207 obj->z_nodelete = true; 1208 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1209 obj->z_loadfltr = true; 1210 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1211 obj->z_interpose = true; 1212 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1213 obj->z_nodeflib = true; 1214 break; 1215 1216 default: 1217 if (!early) { 1218 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1219 (long)dynp->d_tag); 1220 } 1221 break; 1222 } 1223 } 1224 1225 obj->traced = false; 1226 1227 if (plttype == DT_RELA) { 1228 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1229 obj->pltrel = NULL; 1230 obj->pltrelasize = obj->pltrelsize; 1231 obj->pltrelsize = 0; 1232 } 1233 1234 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1235 if (obj->valid_hash_sysv) 1236 obj->dynsymcount = obj->nchains; 1237 else if (obj->valid_hash_gnu) { 1238 obj->dynsymcount = 0; 1239 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1240 if (obj->buckets_gnu[bkt] == 0) 1241 continue; 1242 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1243 do 1244 obj->dynsymcount++; 1245 while ((*hashval++ & 1u) == 0); 1246 } 1247 obj->dynsymcount += obj->symndx_gnu; 1248 } 1249 } 1250 1251 static void 1252 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1253 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1254 { 1255 1256 if (obj->z_origin && obj->origin_path == NULL) { 1257 obj->origin_path = xmalloc(PATH_MAX); 1258 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1) 1259 die(); 1260 } 1261 1262 if (dyn_runpath != NULL) { 1263 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val; 1264 if (obj->z_origin) 1265 obj->runpath = origin_subst(obj->runpath, obj->origin_path); 1266 } 1267 else if (dyn_rpath != NULL) { 1268 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 1269 if (obj->z_origin) 1270 obj->rpath = origin_subst(obj->rpath, obj->origin_path); 1271 } 1272 1273 if (dyn_soname != NULL) 1274 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1275 } 1276 1277 static void 1278 digest_dynamic(Obj_Entry *obj, int early) 1279 { 1280 const Elf_Dyn *dyn_rpath; 1281 const Elf_Dyn *dyn_soname; 1282 const Elf_Dyn *dyn_runpath; 1283 1284 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1285 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath); 1286 } 1287 1288 /* 1289 * Process a shared object's program header. This is used only for the 1290 * main program, when the kernel has already loaded the main program 1291 * into memory before calling the dynamic linker. It creates and 1292 * returns an Obj_Entry structure. 1293 */ 1294 static Obj_Entry * 1295 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1296 { 1297 Obj_Entry *obj; 1298 const Elf_Phdr *phlimit = phdr + phnum; 1299 const Elf_Phdr *ph; 1300 Elf_Addr note_start, note_end; 1301 int nsegs = 0; 1302 1303 obj = obj_new(); 1304 for (ph = phdr; ph < phlimit; ph++) { 1305 if (ph->p_type != PT_PHDR) 1306 continue; 1307 1308 obj->phdr = phdr; 1309 obj->phsize = ph->p_memsz; 1310 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1311 break; 1312 } 1313 1314 obj->stack_flags = PF_X | PF_R | PF_W; 1315 1316 for (ph = phdr; ph < phlimit; ph++) { 1317 switch (ph->p_type) { 1318 1319 case PT_INTERP: 1320 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1321 break; 1322 1323 case PT_LOAD: 1324 if (nsegs == 0) { /* First load segment */ 1325 obj->vaddrbase = trunc_page(ph->p_vaddr); 1326 obj->mapbase = obj->vaddrbase + obj->relocbase; 1327 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1328 obj->vaddrbase; 1329 } else { /* Last load segment */ 1330 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1331 obj->vaddrbase; 1332 } 1333 nsegs++; 1334 break; 1335 1336 case PT_DYNAMIC: 1337 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1338 break; 1339 1340 case PT_TLS: 1341 obj->tlsindex = 1; 1342 obj->tlssize = ph->p_memsz; 1343 obj->tlsalign = ph->p_align; 1344 obj->tlsinitsize = ph->p_filesz; 1345 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1346 break; 1347 1348 case PT_GNU_STACK: 1349 obj->stack_flags = ph->p_flags; 1350 break; 1351 1352 case PT_GNU_RELRO: 1353 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1354 obj->relro_size = round_page(ph->p_memsz); 1355 break; 1356 1357 case PT_NOTE: 1358 obj->note_present = true; 1359 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1360 note_end = note_start + ph->p_filesz; 1361 digest_notes(obj, note_start, note_end); 1362 break; 1363 } 1364 } 1365 if (nsegs < 1) { 1366 _rtld_error("%s: too few PT_LOAD segments", path); 1367 return NULL; 1368 } 1369 1370 obj->entry = entry; 1371 return obj; 1372 } 1373 1374 void 1375 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1376 { 1377 const Elf_Note *note; 1378 const char *note_name; 1379 uintptr_t p; 1380 1381 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1382 note = (const Elf_Note *)((const char *)(note + 1) + 1383 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1384 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1385 if (note->n_namesz != sizeof(NOTE_VENDOR) || 1386 note->n_descsz != sizeof(int32_t)) 1387 continue; 1388 if (note->n_type != ABI_NOTETYPE && 1389 note->n_type != CRT_NOINIT_NOTETYPE) 1390 continue; 1391 note_name = (const char *)(note + 1); 1392 if (strncmp(NOTE_VENDOR, note_name, sizeof(NOTE_VENDOR)) != 0) 1393 continue; 1394 switch (note->n_type) { 1395 case ABI_NOTETYPE: 1396 /* DragonFly osrel note */ 1397 p = (uintptr_t)(note + 1); 1398 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1399 obj->osrel = *(const int32_t *)(p); 1400 dbg("note osrel %d", obj->osrel); 1401 break; 1402 case CRT_NOINIT_NOTETYPE: 1403 /* DragonFly 'crt does not call init' note */ 1404 obj->crt_no_init = true; 1405 dbg("note crt_no_init"); 1406 break; 1407 } 1408 } 1409 } 1410 1411 static Obj_Entry * 1412 dlcheck(void *handle) 1413 { 1414 Obj_Entry *obj; 1415 1416 for (obj = obj_list; obj != NULL; obj = obj->next) 1417 if (obj == (Obj_Entry *) handle) 1418 break; 1419 1420 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1421 _rtld_error("Invalid shared object handle %p", handle); 1422 return NULL; 1423 } 1424 return obj; 1425 } 1426 1427 /* 1428 * If the given object is already in the donelist, return true. Otherwise 1429 * add the object to the list and return false. 1430 */ 1431 static bool 1432 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1433 { 1434 unsigned int i; 1435 1436 for (i = 0; i < dlp->num_used; i++) 1437 if (dlp->objs[i] == obj) 1438 return true; 1439 /* 1440 * Our donelist allocation should always be sufficient. But if 1441 * our threads locking isn't working properly, more shared objects 1442 * could have been loaded since we allocated the list. That should 1443 * never happen, but we'll handle it properly just in case it does. 1444 */ 1445 if (dlp->num_used < dlp->num_alloc) 1446 dlp->objs[dlp->num_used++] = obj; 1447 return false; 1448 } 1449 1450 /* 1451 * Hash function for symbol table lookup. Don't even think about changing 1452 * this. It is specified by the System V ABI. 1453 */ 1454 unsigned long 1455 elf_hash(const char *name) 1456 { 1457 const unsigned char *p = (const unsigned char *) name; 1458 unsigned long h = 0; 1459 unsigned long g; 1460 1461 while (*p != '\0') { 1462 h = (h << 4) + *p++; 1463 if ((g = h & 0xf0000000) != 0) 1464 h ^= g >> 24; 1465 h &= ~g; 1466 } 1467 return h; 1468 } 1469 1470 /* 1471 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1472 * unsigned in case it's implemented with a wider type. 1473 */ 1474 static uint_fast32_t 1475 gnu_hash(const char *s) 1476 { 1477 uint_fast32_t h; 1478 unsigned char c; 1479 1480 h = 5381; 1481 for (c = *s; c != '\0'; c = *++s) 1482 h = h * 33 + c; 1483 return (h & 0xffffffff); 1484 } 1485 1486 /* 1487 * Find the library with the given name, and return its full pathname. 1488 * The returned string is dynamically allocated. Generates an error 1489 * message and returns NULL if the library cannot be found. 1490 * 1491 * If the second argument is non-NULL, then it refers to an already- 1492 * loaded shared object, whose library search path will be searched. 1493 * 1494 * The search order is: 1495 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1496 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1497 * LD_LIBRARY_PATH 1498 * DT_RUNPATH in the referencing file 1499 * ldconfig hints (if -z nodefaultlib, filter out /usr/lib from list) 1500 * /usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1501 * 1502 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1503 */ 1504 static char * 1505 find_library(const char *xname, const Obj_Entry *refobj) 1506 { 1507 char *pathname; 1508 char *name; 1509 bool nodeflib, objgiven; 1510 1511 objgiven = refobj != NULL; 1512 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */ 1513 if (xname[0] != '/' && !trust) { 1514 _rtld_error("Absolute pathname required for shared object \"%s\"", 1515 xname); 1516 return NULL; 1517 } 1518 if (objgiven && refobj->z_origin) { 1519 return (origin_subst(__DECONST(char *, xname), 1520 refobj->origin_path)); 1521 } else { 1522 return (xstrdup(xname)); 1523 } 1524 } 1525 1526 if (libmap_disable || !objgiven || 1527 (name = lm_find(refobj->path, xname)) == NULL) 1528 name = (char *)xname; 1529 1530 dbg(" Searching for \"%s\"", name); 1531 1532 nodeflib = objgiven ? refobj->z_nodeflib : false; 1533 if ((objgiven && 1534 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1535 (objgiven && refobj->runpath == NULL && refobj != obj_main && 1536 (pathname = search_library_path(name, obj_main->rpath)) != NULL) || 1537 (pathname = search_library_path(name, ld_library_path)) != NULL || 1538 (objgiven && 1539 (pathname = search_library_path(name, refobj->runpath)) != NULL) || 1540 (pathname = search_library_path(name, gethints(nodeflib))) != NULL || 1541 (objgiven && !nodeflib && 1542 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)) 1543 return (pathname); 1544 1545 if (objgiven && refobj->path != NULL) { 1546 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 1547 name, basename(refobj->path)); 1548 } else { 1549 _rtld_error("Shared object \"%s\" not found", name); 1550 } 1551 return NULL; 1552 } 1553 1554 /* 1555 * Given a symbol number in a referencing object, find the corresponding 1556 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1557 * no definition was found. Returns a pointer to the Obj_Entry of the 1558 * defining object via the reference parameter DEFOBJ_OUT. 1559 */ 1560 const Elf_Sym * 1561 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1562 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1563 RtldLockState *lockstate) 1564 { 1565 const Elf_Sym *ref; 1566 const Elf_Sym *def; 1567 const Obj_Entry *defobj; 1568 SymLook req; 1569 const char *name; 1570 int res; 1571 1572 /* 1573 * If we have already found this symbol, get the information from 1574 * the cache. 1575 */ 1576 if (symnum >= refobj->dynsymcount) 1577 return NULL; /* Bad object */ 1578 if (cache != NULL && cache[symnum].sym != NULL) { 1579 *defobj_out = cache[symnum].obj; 1580 return cache[symnum].sym; 1581 } 1582 1583 ref = refobj->symtab + symnum; 1584 name = refobj->strtab + ref->st_name; 1585 def = NULL; 1586 defobj = NULL; 1587 1588 /* 1589 * We don't have to do a full scale lookup if the symbol is local. 1590 * We know it will bind to the instance in this load module; to 1591 * which we already have a pointer (ie ref). By not doing a lookup, 1592 * we not only improve performance, but it also avoids unresolvable 1593 * symbols when local symbols are not in the hash table. 1594 * 1595 * This might occur for TLS module relocations, which simply use 1596 * symbol 0. 1597 */ 1598 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1599 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1600 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1601 symnum); 1602 } 1603 symlook_init(&req, name); 1604 req.flags = flags; 1605 req.ventry = fetch_ventry(refobj, symnum); 1606 req.lockstate = lockstate; 1607 res = symlook_default(&req, refobj); 1608 if (res == 0) { 1609 def = req.sym_out; 1610 defobj = req.defobj_out; 1611 } 1612 } else { 1613 def = ref; 1614 defobj = refobj; 1615 } 1616 1617 /* 1618 * If we found no definition and the reference is weak, treat the 1619 * symbol as having the value zero. 1620 */ 1621 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1622 def = &sym_zero; 1623 defobj = obj_main; 1624 } 1625 1626 if (def != NULL) { 1627 *defobj_out = defobj; 1628 /* Record the information in the cache to avoid subsequent lookups. */ 1629 if (cache != NULL) { 1630 cache[symnum].sym = def; 1631 cache[symnum].obj = defobj; 1632 } 1633 } else { 1634 if (refobj != &obj_rtld) 1635 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name); 1636 } 1637 return def; 1638 } 1639 1640 /* 1641 * Return the search path from the ldconfig hints file, reading it if 1642 * necessary. If nostdlib is true, then the default search paths are 1643 * not added to result. 1644 * 1645 * Returns NULL if there are problems with the hints file, 1646 * or if the search path there is empty. 1647 */ 1648 static const char * 1649 gethints(bool nostdlib) 1650 { 1651 static char *hints, *filtered_path; 1652 struct elfhints_hdr hdr; 1653 struct fill_search_info_args sargs, hargs; 1654 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1655 struct dl_serpath *SLPpath, *hintpath; 1656 char *p; 1657 unsigned int SLPndx, hintndx, fndx, fcount; 1658 int fd; 1659 size_t flen; 1660 bool skip; 1661 1662 /* First call, read the hints file */ 1663 if (hints == NULL) { 1664 /* Keep from trying again in case the hints file is bad. */ 1665 hints = ""; 1666 1667 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1668 return (NULL); 1669 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1670 hdr.magic != ELFHINTS_MAGIC || 1671 hdr.version != 1) { 1672 close(fd); 1673 return (NULL); 1674 } 1675 p = xmalloc(hdr.dirlistlen + 1); 1676 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1677 read(fd, p, hdr.dirlistlen + 1) != 1678 (ssize_t)hdr.dirlistlen + 1) { 1679 free(p); 1680 close(fd); 1681 return (NULL); 1682 } 1683 hints = p; 1684 close(fd); 1685 } 1686 1687 /* 1688 * If caller agreed to receive list which includes the default 1689 * paths, we are done. Otherwise, if we still have not 1690 * calculated filtered result, do it now. 1691 */ 1692 if (!nostdlib) 1693 return (hints[0] != '\0' ? hints : NULL); 1694 if (filtered_path != NULL) 1695 goto filt_ret; 1696 1697 /* 1698 * Obtain the list of all configured search paths, and the 1699 * list of the default paths. 1700 * 1701 * First estimate the size of the results. 1702 */ 1703 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1704 smeta.dls_cnt = 0; 1705 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1706 hmeta.dls_cnt = 0; 1707 1708 sargs.request = RTLD_DI_SERINFOSIZE; 1709 sargs.serinfo = &smeta; 1710 hargs.request = RTLD_DI_SERINFOSIZE; 1711 hargs.serinfo = &hmeta; 1712 1713 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1714 path_enumerate(p, fill_search_info, &hargs); 1715 1716 SLPinfo = xmalloc(smeta.dls_size); 1717 hintinfo = xmalloc(hmeta.dls_size); 1718 1719 /* 1720 * Next fetch both sets of paths. 1721 */ 1722 sargs.request = RTLD_DI_SERINFO; 1723 sargs.serinfo = SLPinfo; 1724 sargs.serpath = &SLPinfo->dls_serpath[0]; 1725 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1726 1727 hargs.request = RTLD_DI_SERINFO; 1728 hargs.serinfo = hintinfo; 1729 hargs.serpath = &hintinfo->dls_serpath[0]; 1730 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1731 1732 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1733 path_enumerate(p, fill_search_info, &hargs); 1734 1735 /* 1736 * Now calculate the difference between two sets, by excluding 1737 * standard paths from the full set. 1738 */ 1739 fndx = 0; 1740 fcount = 0; 1741 filtered_path = xmalloc(hdr.dirlistlen + 1); 1742 hintpath = &hintinfo->dls_serpath[0]; 1743 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1744 skip = false; 1745 SLPpath = &SLPinfo->dls_serpath[0]; 1746 /* 1747 * Check each standard path against current. 1748 */ 1749 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1750 /* matched, skip the path */ 1751 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1752 skip = true; 1753 break; 1754 } 1755 } 1756 if (skip) 1757 continue; 1758 /* 1759 * Not matched against any standard path, add the path 1760 * to result. Separate consecutive paths with ':'. 1761 */ 1762 if (fcount > 0) { 1763 filtered_path[fndx] = ':'; 1764 fndx++; 1765 } 1766 fcount++; 1767 flen = strlen(hintpath->dls_name); 1768 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1769 fndx += flen; 1770 } 1771 filtered_path[fndx] = '\0'; 1772 1773 free(SLPinfo); 1774 free(hintinfo); 1775 1776 filt_ret: 1777 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1778 } 1779 1780 static void 1781 init_dag(Obj_Entry *root) 1782 { 1783 const Needed_Entry *needed; 1784 const Objlist_Entry *elm; 1785 DoneList donelist; 1786 1787 if (root->dag_inited) 1788 return; 1789 donelist_init(&donelist); 1790 1791 /* Root object belongs to own DAG. */ 1792 objlist_push_tail(&root->dldags, root); 1793 objlist_push_tail(&root->dagmembers, root); 1794 donelist_check(&donelist, root); 1795 1796 /* 1797 * Add dependencies of root object to DAG in breadth order 1798 * by exploiting the fact that each new object get added 1799 * to the tail of the dagmembers list. 1800 */ 1801 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1802 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1803 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1804 continue; 1805 objlist_push_tail(&needed->obj->dldags, root); 1806 objlist_push_tail(&root->dagmembers, needed->obj); 1807 } 1808 } 1809 root->dag_inited = true; 1810 } 1811 1812 static void 1813 process_nodelete(Obj_Entry *root) 1814 { 1815 const Objlist_Entry *elm; 1816 1817 /* 1818 * Walk over object DAG and process every dependent object that 1819 * is marked as DF_1_NODELETE. They need to grow their own DAG, 1820 * which then should have its reference upped separately. 1821 */ 1822 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1823 if (elm->obj != NULL && elm->obj->z_nodelete && 1824 !elm->obj->ref_nodel) { 1825 dbg("obj %s nodelete", elm->obj->path); 1826 init_dag(elm->obj); 1827 ref_dag(elm->obj); 1828 elm->obj->ref_nodel = true; 1829 } 1830 } 1831 } 1832 1833 /* 1834 * Initialize the dynamic linker. The argument is the address at which 1835 * the dynamic linker has been mapped into memory. The primary task of 1836 * this function is to relocate the dynamic linker. 1837 */ 1838 static void 1839 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 1840 { 1841 Obj_Entry objtmp; /* Temporary rtld object */ 1842 const Elf_Dyn *dyn_rpath; 1843 const Elf_Dyn *dyn_soname; 1844 const Elf_Dyn *dyn_runpath; 1845 1846 /* 1847 * Conjure up an Obj_Entry structure for the dynamic linker. 1848 * 1849 * The "path" member can't be initialized yet because string constants 1850 * cannot yet be accessed. Below we will set it correctly. 1851 */ 1852 memset(&objtmp, 0, sizeof(objtmp)); 1853 objtmp.path = NULL; 1854 objtmp.rtld = true; 1855 objtmp.mapbase = mapbase; 1856 #ifdef PIC 1857 objtmp.relocbase = mapbase; 1858 #endif 1859 if (RTLD_IS_DYNAMIC()) { 1860 objtmp.dynamic = rtld_dynamic(&objtmp); 1861 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 1862 assert(objtmp.needed == NULL); 1863 assert(!objtmp.textrel); 1864 1865 /* 1866 * Temporarily put the dynamic linker entry into the object list, so 1867 * that symbols can be found. 1868 */ 1869 1870 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 1871 } 1872 1873 /* Initialize the object list. */ 1874 obj_tail = &obj_list; 1875 1876 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1877 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1878 1879 #ifdef ENABLE_OSRELDATE 1880 if (aux_info[AT_OSRELDATE] != NULL) 1881 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 1882 #endif 1883 1884 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 1885 1886 /* Replace the path with a dynamically allocated copy. */ 1887 obj_rtld.path = xstrdup(PATH_RTLD); 1888 1889 r_debug.r_brk = r_debug_state; 1890 r_debug.r_state = RT_CONSISTENT; 1891 } 1892 1893 /* 1894 * Add the init functions from a needed object list (and its recursive 1895 * needed objects) to "list". This is not used directly; it is a helper 1896 * function for initlist_add_objects(). The write lock must be held 1897 * when this function is called. 1898 */ 1899 static void 1900 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 1901 { 1902 /* Recursively process the successor needed objects. */ 1903 if (needed->next != NULL) 1904 initlist_add_neededs(needed->next, list); 1905 1906 /* Process the current needed object. */ 1907 if (needed->obj != NULL) 1908 initlist_add_objects(needed->obj, &needed->obj->next, list); 1909 } 1910 1911 /* 1912 * Scan all of the DAGs rooted in the range of objects from "obj" to 1913 * "tail" and add their init functions to "list". This recurses over 1914 * the DAGs and ensure the proper init ordering such that each object's 1915 * needed libraries are initialized before the object itself. At the 1916 * same time, this function adds the objects to the global finalization 1917 * list "list_fini" in the opposite order. The write lock must be 1918 * held when this function is called. 1919 */ 1920 static void 1921 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list) 1922 { 1923 1924 if (obj->init_scanned || obj->init_done) 1925 return; 1926 obj->init_scanned = true; 1927 1928 /* Recursively process the successor objects. */ 1929 if (&obj->next != tail) 1930 initlist_add_objects(obj->next, tail, list); 1931 1932 /* Recursively process the needed objects. */ 1933 if (obj->needed != NULL) 1934 initlist_add_neededs(obj->needed, list); 1935 if (obj->needed_filtees != NULL) 1936 initlist_add_neededs(obj->needed_filtees, list); 1937 if (obj->needed_aux_filtees != NULL) 1938 initlist_add_neededs(obj->needed_aux_filtees, list); 1939 1940 /* Add the object to the init list. */ 1941 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL || 1942 obj->init_array != (Elf_Addr)NULL) 1943 objlist_push_tail(list, obj); 1944 1945 /* Add the object to the global fini list in the reverse order. */ 1946 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 1947 && !obj->on_fini_list) { 1948 objlist_push_head(&list_fini, obj); 1949 obj->on_fini_list = true; 1950 } 1951 } 1952 1953 #ifndef FPTR_TARGET 1954 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 1955 #endif 1956 1957 static void 1958 free_needed_filtees(Needed_Entry *n) 1959 { 1960 Needed_Entry *needed, *needed1; 1961 1962 for (needed = n; needed != NULL; needed = needed->next) { 1963 if (needed->obj != NULL) { 1964 dlclose(needed->obj); 1965 needed->obj = NULL; 1966 } 1967 } 1968 for (needed = n; needed != NULL; needed = needed1) { 1969 needed1 = needed->next; 1970 free(needed); 1971 } 1972 } 1973 1974 static void 1975 unload_filtees(Obj_Entry *obj) 1976 { 1977 1978 free_needed_filtees(obj->needed_filtees); 1979 obj->needed_filtees = NULL; 1980 free_needed_filtees(obj->needed_aux_filtees); 1981 obj->needed_aux_filtees = NULL; 1982 obj->filtees_loaded = false; 1983 } 1984 1985 static void 1986 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 1987 RtldLockState *lockstate) 1988 { 1989 1990 for (; needed != NULL; needed = needed->next) { 1991 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 1992 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 1993 RTLD_LOCAL, lockstate); 1994 } 1995 } 1996 1997 static void 1998 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 1999 { 2000 2001 lock_restart_for_upgrade(lockstate); 2002 if (!obj->filtees_loaded) { 2003 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2004 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2005 obj->filtees_loaded = true; 2006 } 2007 } 2008 2009 static int 2010 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2011 { 2012 Obj_Entry *obj1; 2013 2014 for (; needed != NULL; needed = needed->next) { 2015 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2016 flags & ~RTLD_LO_NOLOAD); 2017 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2018 return (-1); 2019 } 2020 return (0); 2021 } 2022 2023 /* 2024 * Given a shared object, traverse its list of needed objects, and load 2025 * each of them. Returns 0 on success. Generates an error message and 2026 * returns -1 on failure. 2027 */ 2028 static int 2029 load_needed_objects(Obj_Entry *first, int flags) 2030 { 2031 Obj_Entry *obj; 2032 2033 for (obj = first; obj != NULL; obj = obj->next) { 2034 if (process_needed(obj, obj->needed, flags) == -1) 2035 return (-1); 2036 } 2037 return (0); 2038 } 2039 2040 static int 2041 load_preload_objects(void) 2042 { 2043 char *p = ld_preload; 2044 Obj_Entry *obj; 2045 static const char delim[] = " \t:;"; 2046 2047 if (p == NULL) 2048 return 0; 2049 2050 p += strspn(p, delim); 2051 while (*p != '\0') { 2052 size_t len = strcspn(p, delim); 2053 char savech; 2054 SymLook req; 2055 int res; 2056 2057 savech = p[len]; 2058 p[len] = '\0'; 2059 obj = load_object(p, -1, NULL, 0); 2060 if (obj == NULL) 2061 return -1; /* XXX - cleanup */ 2062 obj->z_interpose = true; 2063 p[len] = savech; 2064 p += len; 2065 p += strspn(p, delim); 2066 2067 /* Check for the magic tracing function */ 2068 symlook_init(&req, RTLD_FUNCTRACE); 2069 res = symlook_obj(&req, obj); 2070 if (res == 0) { 2071 rtld_functrace = (void *)(req.defobj_out->relocbase + 2072 req.sym_out->st_value); 2073 rtld_functrace_obj = req.defobj_out; 2074 } 2075 } 2076 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2077 return 0; 2078 } 2079 2080 static const char * 2081 printable_path(const char *path) 2082 { 2083 2084 return (path == NULL ? "<unknown>" : path); 2085 } 2086 2087 /* 2088 * Load a shared object into memory, if it is not already loaded. The 2089 * object may be specified by name or by user-supplied file descriptor 2090 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2091 * duplicate is. 2092 * 2093 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2094 * on failure. 2095 */ 2096 static Obj_Entry * 2097 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2098 { 2099 Obj_Entry *obj; 2100 int fd; 2101 struct stat sb; 2102 char *path; 2103 2104 if (name != NULL) { 2105 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 2106 if (object_match_name(obj, name)) 2107 return (obj); 2108 } 2109 2110 path = find_library(name, refobj); 2111 if (path == NULL) 2112 return (NULL); 2113 } else 2114 path = NULL; 2115 2116 /* 2117 * If we didn't find a match by pathname, or the name is not 2118 * supplied, open the file and check again by device and inode. 2119 * This avoids false mismatches caused by multiple links or ".." 2120 * in pathnames. 2121 * 2122 * To avoid a race, we open the file and use fstat() rather than 2123 * using stat(). 2124 */ 2125 fd = -1; 2126 if (fd_u == -1) { 2127 if ((fd = open(path, O_RDONLY | O_CLOEXEC)) == -1) { 2128 _rtld_error("Cannot open \"%s\"", path); 2129 free(path); 2130 return (NULL); 2131 } 2132 } else { 2133 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2134 if (fd == -1) { 2135 /* 2136 * Temporary, remove at 3.6 branch 2137 * User might not have latest kernel installed 2138 * so fall back to old command for a while 2139 */ 2140 fd = dup(fd_u); 2141 if (fd == -1 || (fcntl(fd, F_SETFD, FD_CLOEXEC) == -1)) { 2142 _rtld_error("Cannot dup fd"); 2143 free(path); 2144 return (NULL); 2145 } 2146 } 2147 } 2148 if (fstat(fd, &sb) == -1) { 2149 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2150 close(fd); 2151 free(path); 2152 return NULL; 2153 } 2154 for (obj = obj_list->next; obj != NULL; obj = obj->next) 2155 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2156 break; 2157 if (obj != NULL && name != NULL) { 2158 object_add_name(obj, name); 2159 free(path); 2160 close(fd); 2161 return obj; 2162 } 2163 if (flags & RTLD_LO_NOLOAD) { 2164 free(path); 2165 close(fd); 2166 return (NULL); 2167 } 2168 2169 /* First use of this object, so we must map it in */ 2170 obj = do_load_object(fd, name, path, &sb, flags); 2171 if (obj == NULL) 2172 free(path); 2173 close(fd); 2174 2175 return obj; 2176 } 2177 2178 static Obj_Entry * 2179 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2180 int flags) 2181 { 2182 Obj_Entry *obj; 2183 struct statfs fs; 2184 2185 /* 2186 * but first, make sure that environment variables haven't been 2187 * used to circumvent the noexec flag on a filesystem. 2188 */ 2189 if (dangerous_ld_env) { 2190 if (fstatfs(fd, &fs) != 0) { 2191 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2192 return NULL; 2193 } 2194 if (fs.f_flags & MNT_NOEXEC) { 2195 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 2196 return NULL; 2197 } 2198 } 2199 dbg("loading \"%s\"", printable_path(path)); 2200 obj = map_object(fd, printable_path(path), sbp); 2201 if (obj == NULL) 2202 return NULL; 2203 2204 /* 2205 * If DT_SONAME is present in the object, digest_dynamic2 already 2206 * added it to the object names. 2207 */ 2208 if (name != NULL) 2209 object_add_name(obj, name); 2210 obj->path = path; 2211 digest_dynamic(obj, 0); 2212 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2213 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2214 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2215 RTLD_LO_DLOPEN) { 2216 dbg("refusing to load non-loadable \"%s\"", obj->path); 2217 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2218 munmap(obj->mapbase, obj->mapsize); 2219 obj_free(obj); 2220 return (NULL); 2221 } 2222 2223 *obj_tail = obj; 2224 obj_tail = &obj->next; 2225 obj_count++; 2226 obj_loads++; 2227 linkmap_add(obj); /* for GDB & dlinfo() */ 2228 max_stack_flags |= obj->stack_flags; 2229 2230 dbg(" %p .. %p: %s", obj->mapbase, 2231 obj->mapbase + obj->mapsize - 1, obj->path); 2232 if (obj->textrel) 2233 dbg(" WARNING: %s has impure text", obj->path); 2234 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2235 obj->path); 2236 2237 return obj; 2238 } 2239 2240 static Obj_Entry * 2241 obj_from_addr(const void *addr) 2242 { 2243 Obj_Entry *obj; 2244 2245 for (obj = obj_list; obj != NULL; obj = obj->next) { 2246 if (addr < (void *) obj->mapbase) 2247 continue; 2248 if (addr < (void *) (obj->mapbase + obj->mapsize)) 2249 return obj; 2250 } 2251 return NULL; 2252 } 2253 2254 /* 2255 * If the main program is defined with a .preinit_array section, call 2256 * each function in order. This must occur before the initialization 2257 * of any shared object or the main program. 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 2308 /* Remove object from fini list to prevent recursive invocation. */ 2309 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2310 /* 2311 * XXX: If a dlopen() call references an object while the 2312 * fini function is in progress, we might end up trying to 2313 * unload the referenced object in dlclose() or the object 2314 * won't be unloaded although its fini function has been 2315 * called. 2316 */ 2317 lock_release(rtld_bind_lock, lockstate); 2318 2319 /* 2320 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. When this 2321 * happens, DT_FINI_ARRAY is processed first, and it is also processed 2322 * backwards. It is possible to encounter DT_FINI_ARRAY elements with 2323 * values of 0 or 1, but they need to be ignored. 2324 */ 2325 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2326 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2327 for (index = elm->obj->fini_array_num - 1; index >= 0; index--) { 2328 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2329 dbg("calling fini array function for %s at %p", 2330 elm->obj->path, (void *)fini_addr[index]); 2331 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2332 (void *)fini_addr[index], 0, 0, elm->obj->path); 2333 call_initfini_pointer(elm->obj, fini_addr[index]); 2334 } 2335 } 2336 } 2337 if (elm->obj->fini != (Elf_Addr)NULL) { 2338 dbg("calling fini function for %s at %p", elm->obj->path, 2339 (void *)elm->obj->fini); 2340 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2341 0, 0, elm->obj->path); 2342 call_initfini_pointer(elm->obj, elm->obj->fini); 2343 } 2344 wlock_acquire(rtld_bind_lock, lockstate); 2345 /* No need to free anything if process is going down. */ 2346 if (root != NULL) 2347 free(elm); 2348 /* 2349 * We must restart the list traversal after every fini call 2350 * because a dlclose() call from the fini function or from 2351 * another thread might have modified the reference counts. 2352 */ 2353 break; 2354 } 2355 } while (elm != NULL); 2356 errmsg_restore(saved_msg); 2357 } 2358 2359 /* 2360 * Call the initialization functions for each of the objects in 2361 * "list". All of the objects are expected to have non-NULL init 2362 * functions. 2363 */ 2364 static void 2365 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2366 { 2367 Objlist_Entry *elm; 2368 Obj_Entry *obj; 2369 char *saved_msg; 2370 Elf_Addr *init_addr; 2371 int index; 2372 2373 /* 2374 * Clean init_scanned flag so that objects can be rechecked and 2375 * possibly initialized earlier if any of vectors called below 2376 * cause the change by using dlopen. 2377 */ 2378 for (obj = obj_list; obj != NULL; obj = obj->next) 2379 obj->init_scanned = false; 2380 2381 /* 2382 * Preserve the current error message since an init function might 2383 * call into the dynamic linker and overwrite it. 2384 */ 2385 saved_msg = errmsg_save(); 2386 STAILQ_FOREACH(elm, list, link) { 2387 if (elm->obj->init_done) /* Initialized early. */ 2388 continue; 2389 2390 /* 2391 * Race: other thread might try to use this object before current 2392 * one completes the initilization. Not much can be done here 2393 * without better locking. 2394 */ 2395 elm->obj->init_done = true; 2396 lock_release(rtld_bind_lock, lockstate); 2397 2398 /* 2399 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. When 2400 * this happens, DT_INIT is processed first. It is possible to 2401 * encounter DT_INIT_ARRAY elements with values of 0 or 1, but they 2402 * need to be ignored. 2403 */ 2404 if (elm->obj->init != (Elf_Addr)NULL) { 2405 dbg("calling init function for %s at %p", elm->obj->path, 2406 (void *)elm->obj->init); 2407 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2408 0, 0, elm->obj->path); 2409 call_initfini_pointer(elm->obj, elm->obj->init); 2410 } 2411 init_addr = (Elf_Addr *)elm->obj->init_array; 2412 if (init_addr != NULL) { 2413 for (index = 0; index < elm->obj->init_array_num; index++) { 2414 if (init_addr[index] != 0 && init_addr[index] != 1) { 2415 dbg("calling init array function for %s at %p", elm->obj->path, 2416 (void *)init_addr[index]); 2417 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2418 (void *)init_addr[index], 0, 0, elm->obj->path); 2419 call_init_pointer(elm->obj, init_addr[index]); 2420 } 2421 } 2422 } 2423 wlock_acquire(rtld_bind_lock, lockstate); 2424 } 2425 errmsg_restore(saved_msg); 2426 } 2427 2428 static void 2429 objlist_clear(Objlist *list) 2430 { 2431 Objlist_Entry *elm; 2432 2433 while (!STAILQ_EMPTY(list)) { 2434 elm = STAILQ_FIRST(list); 2435 STAILQ_REMOVE_HEAD(list, link); 2436 free(elm); 2437 } 2438 } 2439 2440 static Objlist_Entry * 2441 objlist_find(Objlist *list, const Obj_Entry *obj) 2442 { 2443 Objlist_Entry *elm; 2444 2445 STAILQ_FOREACH(elm, list, link) 2446 if (elm->obj == obj) 2447 return elm; 2448 return NULL; 2449 } 2450 2451 static void 2452 objlist_init(Objlist *list) 2453 { 2454 STAILQ_INIT(list); 2455 } 2456 2457 static void 2458 objlist_push_head(Objlist *list, Obj_Entry *obj) 2459 { 2460 Objlist_Entry *elm; 2461 2462 elm = NEW(Objlist_Entry); 2463 elm->obj = obj; 2464 STAILQ_INSERT_HEAD(list, elm, link); 2465 } 2466 2467 static void 2468 objlist_push_tail(Objlist *list, Obj_Entry *obj) 2469 { 2470 Objlist_Entry *elm; 2471 2472 elm = NEW(Objlist_Entry); 2473 elm->obj = obj; 2474 STAILQ_INSERT_TAIL(list, elm, link); 2475 } 2476 2477 static void 2478 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2479 { 2480 Objlist_Entry *elm, *listelm; 2481 2482 STAILQ_FOREACH(listelm, list, link) { 2483 if (listelm->obj == listobj) 2484 break; 2485 } 2486 elm = NEW(Objlist_Entry); 2487 elm->obj = obj; 2488 if (listelm != NULL) 2489 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2490 else 2491 STAILQ_INSERT_TAIL(list, elm, link); 2492 } 2493 2494 static void 2495 objlist_remove(Objlist *list, Obj_Entry *obj) 2496 { 2497 Objlist_Entry *elm; 2498 2499 if ((elm = objlist_find(list, obj)) != NULL) { 2500 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2501 free(elm); 2502 } 2503 } 2504 2505 /* 2506 * Relocate dag rooted in the specified object. 2507 * Returns 0 on success, or -1 on failure. 2508 */ 2509 2510 static int 2511 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2512 int flags, RtldLockState *lockstate) 2513 { 2514 Objlist_Entry *elm; 2515 int error; 2516 2517 error = 0; 2518 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2519 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2520 lockstate); 2521 if (error == -1) 2522 break; 2523 } 2524 return (error); 2525 } 2526 2527 /* 2528 * Relocate single object. 2529 * Returns 0 on success, or -1 on failure. 2530 */ 2531 static int 2532 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2533 int flags, RtldLockState *lockstate) 2534 { 2535 2536 if (obj->relocated) 2537 return (0); 2538 obj->relocated = true; 2539 if (obj != rtldobj) 2540 dbg("relocating \"%s\"", obj->path); 2541 2542 if (obj->symtab == NULL || obj->strtab == NULL || 2543 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2544 _rtld_error("%s: Shared object has no run-time symbol table", 2545 obj->path); 2546 return (-1); 2547 } 2548 2549 if (obj->textrel) { 2550 /* There are relocations to the write-protected text segment. */ 2551 if (mprotect(obj->mapbase, obj->textsize, 2552 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) { 2553 _rtld_error("%s: Cannot write-enable text segment: %s", 2554 obj->path, rtld_strerror(errno)); 2555 return (-1); 2556 } 2557 } 2558 2559 /* Process the non-PLT relocations. */ 2560 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2561 return (-1); 2562 2563 /* 2564 * Reprotect the text segment. Make sure it is included in the 2565 * core dump since we modified it. This unfortunately causes the 2566 * entire text segment to core-out but we don't have much of a 2567 * choice. We could try to only reenable core dumps on pages 2568 * in which relocations occured but that is likely most of the text 2569 * pages anyway, and even that would not work because the rest of 2570 * the text pages would wind up as a read-only OBJT_DEFAULT object 2571 * (created due to our modifications) backed by the original OBJT_VNODE 2572 * object, and the ELF coredump code is currently only able to dump 2573 * vnode records for pure vnode-backed mappings, not vnode backings 2574 * to memory objects. 2575 */ 2576 if (obj->textrel) { 2577 madvise(obj->mapbase, obj->textsize, MADV_CORE); 2578 if (mprotect(obj->mapbase, obj->textsize, 2579 PROT_READ|PROT_EXEC) == -1) { 2580 _rtld_error("%s: Cannot write-protect text segment: %s", 2581 obj->path, rtld_strerror(errno)); 2582 return (-1); 2583 } 2584 } 2585 2586 2587 /* Set the special PLT or GOT entries. */ 2588 init_pltgot(obj); 2589 2590 /* Process the PLT relocations. */ 2591 if (reloc_plt(obj) == -1) 2592 return (-1); 2593 /* Relocate the jump slots if we are doing immediate binding. */ 2594 if (obj->bind_now || bind_now) 2595 if (reloc_jmpslots(obj, flags, lockstate) == -1) 2596 return (-1); 2597 2598 /* 2599 * Set up the magic number and version in the Obj_Entry. These 2600 * were checked in the crt1.o from the original ElfKit, so we 2601 * set them for backward compatibility. 2602 */ 2603 obj->magic = RTLD_MAGIC; 2604 obj->version = RTLD_VERSION; 2605 2606 /* 2607 * Set relocated data to read-only status if protection specified 2608 */ 2609 2610 if (obj->relro_size) { 2611 if (mprotect(obj->relro_page, obj->relro_size, PROT_READ) == -1) { 2612 _rtld_error("%s: Cannot enforce relro relocation: %s", 2613 obj->path, rtld_strerror(errno)); 2614 return (-1); 2615 } 2616 } 2617 return (0); 2618 } 2619 2620 /* 2621 * Relocate newly-loaded shared objects. The argument is a pointer to 2622 * the Obj_Entry for the first such object. All objects from the first 2623 * to the end of the list of objects are relocated. Returns 0 on success, 2624 * or -1 on failure. 2625 */ 2626 static int 2627 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2628 int flags, RtldLockState *lockstate) 2629 { 2630 Obj_Entry *obj; 2631 int error; 2632 2633 for (error = 0, obj = first; obj != NULL; obj = obj->next) { 2634 error = relocate_object(obj, bind_now, rtldobj, flags, 2635 lockstate); 2636 if (error == -1) 2637 break; 2638 } 2639 return (error); 2640 } 2641 2642 /* 2643 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2644 * referencing STT_GNU_IFUNC symbols is postponed till the other 2645 * relocations are done. The indirect functions specified as 2646 * ifunc are allowed to call other symbols, so we need to have 2647 * objects relocated before asking for resolution from indirects. 2648 * 2649 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2650 * instead of the usual lazy handling of PLT slots. It is 2651 * consistent with how GNU does it. 2652 */ 2653 static int 2654 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2655 RtldLockState *lockstate) 2656 { 2657 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2658 return (-1); 2659 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2660 reloc_gnu_ifunc(obj, flags, lockstate) == -1) 2661 return (-1); 2662 return (0); 2663 } 2664 2665 static int 2666 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags, 2667 RtldLockState *lockstate) 2668 { 2669 Obj_Entry *obj; 2670 2671 for (obj = first; obj != NULL; obj = obj->next) { 2672 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1) 2673 return (-1); 2674 } 2675 return (0); 2676 } 2677 2678 static int 2679 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2680 RtldLockState *lockstate) 2681 { 2682 Objlist_Entry *elm; 2683 2684 STAILQ_FOREACH(elm, list, link) { 2685 if (resolve_object_ifunc(elm->obj, bind_now, flags, 2686 lockstate) == -1) 2687 return (-1); 2688 } 2689 return (0); 2690 } 2691 2692 /* 2693 * Cleanup procedure. It will be called (by the atexit mechanism) just 2694 * before the process exits. 2695 */ 2696 static void 2697 rtld_exit(void) 2698 { 2699 RtldLockState lockstate; 2700 2701 wlock_acquire(rtld_bind_lock, &lockstate); 2702 dbg("rtld_exit()"); 2703 objlist_call_fini(&list_fini, NULL, &lockstate); 2704 /* No need to remove the items from the list, since we are exiting. */ 2705 if (!libmap_disable) 2706 lm_fini(); 2707 lock_release(rtld_bind_lock, &lockstate); 2708 } 2709 2710 /* 2711 * Iterate over a search path, translate each element, and invoke the 2712 * callback on the result. 2713 */ 2714 static void * 2715 path_enumerate(const char *path, path_enum_proc callback, void *arg) 2716 { 2717 const char *trans; 2718 if (path == NULL) 2719 return (NULL); 2720 2721 path += strspn(path, ":;"); 2722 while (*path != '\0') { 2723 size_t len; 2724 char *res; 2725 2726 len = strcspn(path, ":;"); 2727 trans = lm_findn(NULL, path, len); 2728 if (trans) 2729 res = callback(trans, strlen(trans), arg); 2730 else 2731 res = callback(path, len, arg); 2732 2733 if (res != NULL) 2734 return (res); 2735 2736 path += len; 2737 path += strspn(path, ":;"); 2738 } 2739 2740 return (NULL); 2741 } 2742 2743 struct try_library_args { 2744 const char *name; 2745 size_t namelen; 2746 char *buffer; 2747 size_t buflen; 2748 }; 2749 2750 static void * 2751 try_library_path(const char *dir, size_t dirlen, void *param) 2752 { 2753 struct try_library_args *arg; 2754 2755 arg = param; 2756 if (*dir == '/' || trust) { 2757 char *pathname; 2758 2759 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 2760 return (NULL); 2761 2762 pathname = arg->buffer; 2763 strncpy(pathname, dir, dirlen); 2764 pathname[dirlen] = '/'; 2765 strcpy(pathname + dirlen + 1, arg->name); 2766 2767 dbg(" Trying \"%s\"", pathname); 2768 if (access(pathname, F_OK) == 0) { /* We found it */ 2769 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 2770 strcpy(pathname, arg->buffer); 2771 return (pathname); 2772 } 2773 } 2774 return (NULL); 2775 } 2776 2777 static char * 2778 search_library_path(const char *name, const char *path) 2779 { 2780 char *p; 2781 struct try_library_args arg; 2782 2783 if (path == NULL) 2784 return NULL; 2785 2786 arg.name = name; 2787 arg.namelen = strlen(name); 2788 arg.buffer = xmalloc(PATH_MAX); 2789 arg.buflen = PATH_MAX; 2790 2791 p = path_enumerate(path, try_library_path, &arg); 2792 2793 free(arg.buffer); 2794 2795 return (p); 2796 } 2797 2798 int 2799 dlclose(void *handle) 2800 { 2801 Obj_Entry *root; 2802 RtldLockState lockstate; 2803 2804 wlock_acquire(rtld_bind_lock, &lockstate); 2805 root = dlcheck(handle); 2806 if (root == NULL) { 2807 lock_release(rtld_bind_lock, &lockstate); 2808 return -1; 2809 } 2810 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 2811 root->path); 2812 2813 /* Unreference the object and its dependencies. */ 2814 root->dl_refcount--; 2815 2816 if (root->refcount == 1) { 2817 /* 2818 * The object will be no longer referenced, so we must unload it. 2819 * First, call the fini functions. 2820 */ 2821 objlist_call_fini(&list_fini, root, &lockstate); 2822 2823 unref_dag(root); 2824 2825 /* Finish cleaning up the newly-unreferenced objects. */ 2826 GDB_STATE(RT_DELETE,&root->linkmap); 2827 unload_object(root); 2828 GDB_STATE(RT_CONSISTENT,NULL); 2829 } else 2830 unref_dag(root); 2831 2832 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 2833 lock_release(rtld_bind_lock, &lockstate); 2834 return 0; 2835 } 2836 2837 char * 2838 dlerror(void) 2839 { 2840 char *msg = error_message; 2841 error_message = NULL; 2842 return msg; 2843 } 2844 2845 void * 2846 dlopen(const char *name, int mode) 2847 { 2848 2849 return (rtld_dlopen(name, -1, mode)); 2850 } 2851 2852 void * 2853 fdlopen(int fd, int mode) 2854 { 2855 2856 return (rtld_dlopen(NULL, fd, mode)); 2857 } 2858 2859 static void * 2860 rtld_dlopen(const char *name, int fd, int mode) 2861 { 2862 RtldLockState lockstate; 2863 int lo_flags; 2864 2865 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 2866 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 2867 if (ld_tracing != NULL) { 2868 rlock_acquire(rtld_bind_lock, &lockstate); 2869 if (sigsetjmp(lockstate.env, 0) != 0) 2870 lock_upgrade(rtld_bind_lock, &lockstate); 2871 environ = (char **)*get_program_var_addr("environ", &lockstate); 2872 lock_release(rtld_bind_lock, &lockstate); 2873 } 2874 lo_flags = RTLD_LO_DLOPEN; 2875 if (mode & RTLD_NODELETE) 2876 lo_flags |= RTLD_LO_NODELETE; 2877 if (mode & RTLD_NOLOAD) 2878 lo_flags |= RTLD_LO_NOLOAD; 2879 if (ld_tracing != NULL) 2880 lo_flags |= RTLD_LO_TRACE; 2881 2882 return (dlopen_object(name, fd, obj_main, lo_flags, 2883 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 2884 } 2885 2886 static void 2887 dlopen_cleanup(Obj_Entry *obj) 2888 { 2889 2890 obj->dl_refcount--; 2891 unref_dag(obj); 2892 if (obj->refcount == 0) 2893 unload_object(obj); 2894 } 2895 2896 static Obj_Entry * 2897 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 2898 int mode, RtldLockState *lockstate) 2899 { 2900 Obj_Entry **old_obj_tail; 2901 Obj_Entry *obj; 2902 Objlist initlist; 2903 RtldLockState mlockstate; 2904 int result; 2905 2906 objlist_init(&initlist); 2907 2908 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 2909 wlock_acquire(rtld_bind_lock, &mlockstate); 2910 lockstate = &mlockstate; 2911 } 2912 GDB_STATE(RT_ADD,NULL); 2913 2914 old_obj_tail = obj_tail; 2915 obj = NULL; 2916 if (name == NULL && fd == -1) { 2917 obj = obj_main; 2918 obj->refcount++; 2919 } else { 2920 obj = load_object(name, fd, refobj, lo_flags); 2921 } 2922 2923 if (obj) { 2924 obj->dl_refcount++; 2925 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 2926 objlist_push_tail(&list_global, obj); 2927 if (*old_obj_tail != NULL) { /* We loaded something new. */ 2928 assert(*old_obj_tail == obj); 2929 result = load_needed_objects(obj, 2930 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 2931 init_dag(obj); 2932 ref_dag(obj); 2933 if (result != -1) 2934 result = rtld_verify_versions(&obj->dagmembers); 2935 if (result != -1 && ld_tracing) 2936 goto trace; 2937 if (result == -1 || relocate_object_dag(obj, 2938 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 2939 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 2940 lockstate) == -1) { 2941 dlopen_cleanup(obj); 2942 obj = NULL; 2943 } else if (lo_flags & RTLD_LO_EARLY) { 2944 /* 2945 * Do not call the init functions for early loaded 2946 * filtees. The image is still not initialized enough 2947 * for them to work. 2948 * 2949 * Our object is found by the global object list and 2950 * will be ordered among all init calls done right 2951 * before transferring control to main. 2952 */ 2953 } else { 2954 /* Make list of init functions to call. */ 2955 initlist_add_objects(obj, &obj->next, &initlist); 2956 } 2957 /* 2958 * Process all no_delete objects here, given them own 2959 * DAGs to prevent their dependencies from being unloaded. 2960 * This has to be done after we have loaded all of the 2961 * dependencies, so that we do not miss any. 2962 */ 2963 if (obj != NULL) 2964 process_nodelete(obj); 2965 } else { 2966 /* 2967 * Bump the reference counts for objects on this DAG. If 2968 * this is the first dlopen() call for the object that was 2969 * already loaded as a dependency, initialize the dag 2970 * starting at it. 2971 */ 2972 init_dag(obj); 2973 ref_dag(obj); 2974 2975 if ((lo_flags & RTLD_LO_TRACE) != 0) 2976 goto trace; 2977 } 2978 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 2979 obj->z_nodelete) && !obj->ref_nodel) { 2980 dbg("obj %s nodelete", obj->path); 2981 ref_dag(obj); 2982 obj->z_nodelete = obj->ref_nodel = true; 2983 } 2984 } 2985 2986 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 2987 name); 2988 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 2989 2990 if (!(lo_flags & RTLD_LO_EARLY)) { 2991 map_stacks_exec(lockstate); 2992 } 2993 2994 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 2995 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 2996 lockstate) == -1) { 2997 objlist_clear(&initlist); 2998 dlopen_cleanup(obj); 2999 if (lockstate == &mlockstate) 3000 lock_release(rtld_bind_lock, lockstate); 3001 return (NULL); 3002 } 3003 3004 if (!(lo_flags & RTLD_LO_EARLY)) { 3005 /* Call the init functions. */ 3006 objlist_call_init(&initlist, lockstate); 3007 } 3008 objlist_clear(&initlist); 3009 if (lockstate == &mlockstate) 3010 lock_release(rtld_bind_lock, lockstate); 3011 return obj; 3012 trace: 3013 trace_loaded_objects(obj); 3014 if (lockstate == &mlockstate) 3015 lock_release(rtld_bind_lock, lockstate); 3016 exit(0); 3017 } 3018 3019 static void * 3020 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3021 int flags) 3022 { 3023 DoneList donelist; 3024 const Obj_Entry *obj, *defobj; 3025 const Elf_Sym *def; 3026 SymLook req; 3027 RtldLockState lockstate; 3028 tls_index ti; 3029 int res; 3030 3031 def = NULL; 3032 defobj = NULL; 3033 symlook_init(&req, name); 3034 req.ventry = ve; 3035 req.flags = flags | SYMLOOK_IN_PLT; 3036 req.lockstate = &lockstate; 3037 3038 rlock_acquire(rtld_bind_lock, &lockstate); 3039 if (sigsetjmp(lockstate.env, 0) != 0) 3040 lock_upgrade(rtld_bind_lock, &lockstate); 3041 if (handle == NULL || handle == RTLD_NEXT || 3042 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3043 3044 if ((obj = obj_from_addr(retaddr)) == NULL) { 3045 _rtld_error("Cannot determine caller's shared object"); 3046 lock_release(rtld_bind_lock, &lockstate); 3047 return NULL; 3048 } 3049 if (handle == NULL) { /* Just the caller's shared object. */ 3050 res = symlook_obj(&req, obj); 3051 if (res == 0) { 3052 def = req.sym_out; 3053 defobj = req.defobj_out; 3054 } 3055 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3056 handle == RTLD_SELF) { /* ... caller included */ 3057 if (handle == RTLD_NEXT) 3058 obj = obj->next; 3059 for (; obj != NULL; obj = obj->next) { 3060 res = symlook_obj(&req, obj); 3061 if (res == 0) { 3062 if (def == NULL || 3063 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3064 def = req.sym_out; 3065 defobj = req.defobj_out; 3066 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3067 break; 3068 } 3069 } 3070 } 3071 /* 3072 * Search the dynamic linker itself, and possibly resolve the 3073 * symbol from there. This is how the application links to 3074 * dynamic linker services such as dlopen. 3075 */ 3076 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3077 res = symlook_obj(&req, &obj_rtld); 3078 if (res == 0) { 3079 def = req.sym_out; 3080 defobj = req.defobj_out; 3081 } 3082 } 3083 } else { 3084 assert(handle == RTLD_DEFAULT); 3085 res = symlook_default(&req, obj); 3086 if (res == 0) { 3087 defobj = req.defobj_out; 3088 def = req.sym_out; 3089 } 3090 } 3091 } else { 3092 if ((obj = dlcheck(handle)) == NULL) { 3093 lock_release(rtld_bind_lock, &lockstate); 3094 return NULL; 3095 } 3096 3097 donelist_init(&donelist); 3098 if (obj->mainprog) { 3099 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3100 res = symlook_global(&req, &donelist); 3101 if (res == 0) { 3102 def = req.sym_out; 3103 defobj = req.defobj_out; 3104 } 3105 /* 3106 * Search the dynamic linker itself, and possibly resolve the 3107 * symbol from there. This is how the application links to 3108 * dynamic linker services such as dlopen. 3109 */ 3110 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3111 res = symlook_obj(&req, &obj_rtld); 3112 if (res == 0) { 3113 def = req.sym_out; 3114 defobj = req.defobj_out; 3115 } 3116 } 3117 } 3118 else { 3119 /* Search the whole DAG rooted at the given object. */ 3120 res = symlook_list(&req, &obj->dagmembers, &donelist); 3121 if (res == 0) { 3122 def = req.sym_out; 3123 defobj = req.defobj_out; 3124 } 3125 } 3126 } 3127 3128 if (def != NULL) { 3129 lock_release(rtld_bind_lock, &lockstate); 3130 3131 /* 3132 * The value required by the caller is derived from the value 3133 * of the symbol. For the ia64 architecture, we need to 3134 * construct a function descriptor which the caller can use to 3135 * call the function with the right 'gp' value. For other 3136 * architectures and for non-functions, the value is simply 3137 * the relocated value of the symbol. 3138 */ 3139 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3140 return (make_function_pointer(def, defobj)); 3141 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3142 return (rtld_resolve_ifunc(defobj, def)); 3143 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3144 ti.ti_module = defobj->tlsindex; 3145 ti.ti_offset = def->st_value; 3146 return (__tls_get_addr(&ti)); 3147 } else 3148 return (defobj->relocbase + def->st_value); 3149 } 3150 3151 _rtld_error("Undefined symbol \"%s\"", name); 3152 lock_release(rtld_bind_lock, &lockstate); 3153 return NULL; 3154 } 3155 3156 void * 3157 dlsym(void *handle, const char *name) 3158 { 3159 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3160 SYMLOOK_DLSYM); 3161 } 3162 3163 dlfunc_t 3164 dlfunc(void *handle, const char *name) 3165 { 3166 union { 3167 void *d; 3168 dlfunc_t f; 3169 } rv; 3170 3171 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3172 SYMLOOK_DLSYM); 3173 return (rv.f); 3174 } 3175 3176 void * 3177 dlvsym(void *handle, const char *name, const char *version) 3178 { 3179 Ver_Entry ventry; 3180 3181 ventry.name = version; 3182 ventry.file = NULL; 3183 ventry.hash = elf_hash(version); 3184 ventry.flags= 0; 3185 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3186 SYMLOOK_DLSYM); 3187 } 3188 3189 int 3190 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3191 { 3192 const Obj_Entry *obj; 3193 RtldLockState lockstate; 3194 3195 rlock_acquire(rtld_bind_lock, &lockstate); 3196 obj = obj_from_addr(addr); 3197 if (obj == NULL) { 3198 _rtld_error("No shared object contains address"); 3199 lock_release(rtld_bind_lock, &lockstate); 3200 return (0); 3201 } 3202 rtld_fill_dl_phdr_info(obj, phdr_info); 3203 lock_release(rtld_bind_lock, &lockstate); 3204 return (1); 3205 } 3206 3207 int 3208 dladdr(const void *addr, Dl_info *info) 3209 { 3210 const Obj_Entry *obj; 3211 const Elf_Sym *def; 3212 void *symbol_addr; 3213 unsigned long symoffset; 3214 RtldLockState lockstate; 3215 3216 rlock_acquire(rtld_bind_lock, &lockstate); 3217 obj = obj_from_addr(addr); 3218 if (obj == NULL) { 3219 _rtld_error("No shared object contains address"); 3220 lock_release(rtld_bind_lock, &lockstate); 3221 return 0; 3222 } 3223 info->dli_fname = obj->path; 3224 info->dli_fbase = obj->mapbase; 3225 info->dli_saddr = NULL; 3226 info->dli_sname = NULL; 3227 3228 /* 3229 * Walk the symbol list looking for the symbol whose address is 3230 * closest to the address sent in. 3231 */ 3232 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3233 def = obj->symtab + symoffset; 3234 3235 /* 3236 * For skip the symbol if st_shndx is either SHN_UNDEF or 3237 * SHN_COMMON. 3238 */ 3239 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3240 continue; 3241 3242 /* 3243 * If the symbol is greater than the specified address, or if it 3244 * is further away from addr than the current nearest symbol, 3245 * then reject it. 3246 */ 3247 symbol_addr = obj->relocbase + def->st_value; 3248 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3249 continue; 3250 3251 /* Update our idea of the nearest symbol. */ 3252 info->dli_sname = obj->strtab + def->st_name; 3253 info->dli_saddr = symbol_addr; 3254 3255 /* Exact match? */ 3256 if (info->dli_saddr == addr) 3257 break; 3258 } 3259 lock_release(rtld_bind_lock, &lockstate); 3260 return 1; 3261 } 3262 3263 int 3264 dlinfo(void *handle, int request, void *p) 3265 { 3266 const Obj_Entry *obj; 3267 RtldLockState lockstate; 3268 int error; 3269 3270 rlock_acquire(rtld_bind_lock, &lockstate); 3271 3272 if (handle == NULL || handle == RTLD_SELF) { 3273 void *retaddr; 3274 3275 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3276 if ((obj = obj_from_addr(retaddr)) == NULL) 3277 _rtld_error("Cannot determine caller's shared object"); 3278 } else 3279 obj = dlcheck(handle); 3280 3281 if (obj == NULL) { 3282 lock_release(rtld_bind_lock, &lockstate); 3283 return (-1); 3284 } 3285 3286 error = 0; 3287 switch (request) { 3288 case RTLD_DI_LINKMAP: 3289 *((struct link_map const **)p) = &obj->linkmap; 3290 break; 3291 case RTLD_DI_ORIGIN: 3292 error = rtld_dirname(obj->path, p); 3293 break; 3294 3295 case RTLD_DI_SERINFOSIZE: 3296 case RTLD_DI_SERINFO: 3297 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3298 break; 3299 3300 default: 3301 _rtld_error("Invalid request %d passed to dlinfo()", request); 3302 error = -1; 3303 } 3304 3305 lock_release(rtld_bind_lock, &lockstate); 3306 3307 return (error); 3308 } 3309 3310 static void 3311 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3312 { 3313 3314 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3315 phdr_info->dlpi_name = STAILQ_FIRST(&obj->names) ? 3316 STAILQ_FIRST(&obj->names)->name : obj->path; 3317 phdr_info->dlpi_phdr = obj->phdr; 3318 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3319 phdr_info->dlpi_tls_modid = obj->tlsindex; 3320 phdr_info->dlpi_tls_data = obj->tlsinit; 3321 phdr_info->dlpi_adds = obj_loads; 3322 phdr_info->dlpi_subs = obj_loads - obj_count; 3323 } 3324 3325 int 3326 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3327 { 3328 struct dl_phdr_info phdr_info; 3329 const Obj_Entry *obj; 3330 RtldLockState bind_lockstate, phdr_lockstate; 3331 int error; 3332 3333 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3334 rlock_acquire(rtld_bind_lock, &bind_lockstate); 3335 3336 error = 0; 3337 3338 for (obj = obj_list; obj != NULL; obj = obj->next) { 3339 rtld_fill_dl_phdr_info(obj, &phdr_info); 3340 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0) 3341 break; 3342 3343 } 3344 if (error == 0) { 3345 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3346 error = callback(&phdr_info, sizeof(phdr_info), param); 3347 } 3348 3349 lock_release(rtld_bind_lock, &bind_lockstate); 3350 lock_release(rtld_phdr_lock, &phdr_lockstate); 3351 3352 return (error); 3353 } 3354 3355 static void * 3356 fill_search_info(const char *dir, size_t dirlen, void *param) 3357 { 3358 struct fill_search_info_args *arg; 3359 3360 arg = param; 3361 3362 if (arg->request == RTLD_DI_SERINFOSIZE) { 3363 arg->serinfo->dls_cnt ++; 3364 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3365 } else { 3366 struct dl_serpath *s_entry; 3367 3368 s_entry = arg->serpath; 3369 s_entry->dls_name = arg->strspace; 3370 s_entry->dls_flags = arg->flags; 3371 3372 strncpy(arg->strspace, dir, dirlen); 3373 arg->strspace[dirlen] = '\0'; 3374 3375 arg->strspace += dirlen + 1; 3376 arg->serpath++; 3377 } 3378 3379 return (NULL); 3380 } 3381 3382 static int 3383 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3384 { 3385 struct dl_serinfo _info; 3386 struct fill_search_info_args args; 3387 3388 args.request = RTLD_DI_SERINFOSIZE; 3389 args.serinfo = &_info; 3390 3391 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3392 _info.dls_cnt = 0; 3393 3394 path_enumerate(obj->rpath, fill_search_info, &args); 3395 path_enumerate(ld_library_path, fill_search_info, &args); 3396 path_enumerate(obj->runpath, fill_search_info, &args); 3397 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args); 3398 if (!obj->z_nodeflib) 3399 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 3400 3401 3402 if (request == RTLD_DI_SERINFOSIZE) { 3403 info->dls_size = _info.dls_size; 3404 info->dls_cnt = _info.dls_cnt; 3405 return (0); 3406 } 3407 3408 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3409 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3410 return (-1); 3411 } 3412 3413 args.request = RTLD_DI_SERINFO; 3414 args.serinfo = info; 3415 args.serpath = &info->dls_serpath[0]; 3416 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3417 3418 args.flags = LA_SER_RUNPATH; 3419 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 3420 return (-1); 3421 3422 args.flags = LA_SER_LIBPATH; 3423 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 3424 return (-1); 3425 3426 args.flags = LA_SER_RUNPATH; 3427 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL) 3428 return (-1); 3429 3430 args.flags = LA_SER_CONFIG; 3431 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args) 3432 != NULL) 3433 return (-1); 3434 3435 args.flags = LA_SER_DEFAULT; 3436 if (!obj->z_nodeflib && 3437 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 3438 return (-1); 3439 return (0); 3440 } 3441 3442 static int 3443 rtld_dirname(const char *path, char *bname) 3444 { 3445 const char *endp; 3446 3447 /* Empty or NULL string gets treated as "." */ 3448 if (path == NULL || *path == '\0') { 3449 bname[0] = '.'; 3450 bname[1] = '\0'; 3451 return (0); 3452 } 3453 3454 /* Strip trailing slashes */ 3455 endp = path + strlen(path) - 1; 3456 while (endp > path && *endp == '/') 3457 endp--; 3458 3459 /* Find the start of the dir */ 3460 while (endp > path && *endp != '/') 3461 endp--; 3462 3463 /* Either the dir is "/" or there are no slashes */ 3464 if (endp == path) { 3465 bname[0] = *endp == '/' ? '/' : '.'; 3466 bname[1] = '\0'; 3467 return (0); 3468 } else { 3469 do { 3470 endp--; 3471 } while (endp > path && *endp == '/'); 3472 } 3473 3474 if (endp - path + 2 > PATH_MAX) 3475 { 3476 _rtld_error("Filename is too long: %s", path); 3477 return(-1); 3478 } 3479 3480 strncpy(bname, path, endp - path + 1); 3481 bname[endp - path + 1] = '\0'; 3482 return (0); 3483 } 3484 3485 static int 3486 rtld_dirname_abs(const char *path, char *base) 3487 { 3488 char base_rel[PATH_MAX]; 3489 3490 if (rtld_dirname(path, base) == -1) 3491 return (-1); 3492 if (base[0] == '/') 3493 return (0); 3494 if (getcwd(base_rel, sizeof(base_rel)) == NULL || 3495 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) || 3496 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel)) 3497 return (-1); 3498 strcpy(base, base_rel); 3499 return (0); 3500 } 3501 3502 static void 3503 linkmap_add(Obj_Entry *obj) 3504 { 3505 struct link_map *l = &obj->linkmap; 3506 struct link_map *prev; 3507 3508 obj->linkmap.l_name = obj->path; 3509 obj->linkmap.l_addr = obj->mapbase; 3510 obj->linkmap.l_ld = obj->dynamic; 3511 #ifdef __mips__ 3512 /* GDB needs load offset on MIPS to use the symbols */ 3513 obj->linkmap.l_offs = obj->relocbase; 3514 #endif 3515 3516 if (r_debug.r_map == NULL) { 3517 r_debug.r_map = l; 3518 return; 3519 } 3520 3521 /* 3522 * Scan to the end of the list, but not past the entry for the 3523 * dynamic linker, which we want to keep at the very end. 3524 */ 3525 for (prev = r_debug.r_map; 3526 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3527 prev = prev->l_next) 3528 ; 3529 3530 /* Link in the new entry. */ 3531 l->l_prev = prev; 3532 l->l_next = prev->l_next; 3533 if (l->l_next != NULL) 3534 l->l_next->l_prev = l; 3535 prev->l_next = l; 3536 } 3537 3538 static void 3539 linkmap_delete(Obj_Entry *obj) 3540 { 3541 struct link_map *l = &obj->linkmap; 3542 3543 if (l->l_prev == NULL) { 3544 if ((r_debug.r_map = l->l_next) != NULL) 3545 l->l_next->l_prev = NULL; 3546 return; 3547 } 3548 3549 if ((l->l_prev->l_next = l->l_next) != NULL) 3550 l->l_next->l_prev = l->l_prev; 3551 } 3552 3553 /* 3554 * Function for the debugger to set a breakpoint on to gain control. 3555 * 3556 * The two parameters allow the debugger to easily find and determine 3557 * what the runtime loader is doing and to whom it is doing it. 3558 * 3559 * When the loadhook trap is hit (r_debug_state, set at program 3560 * initialization), the arguments can be found on the stack: 3561 * 3562 * +8 struct link_map *m 3563 * +4 struct r_debug *rd 3564 * +0 RetAddr 3565 */ 3566 void 3567 r_debug_state(struct r_debug* rd, struct link_map *m) 3568 { 3569 /* 3570 * The following is a hack to force the compiler to emit calls to 3571 * this function, even when optimizing. If the function is empty, 3572 * the compiler is not obliged to emit any code for calls to it, 3573 * even when marked __noinline. However, gdb depends on those 3574 * calls being made. 3575 */ 3576 __asm __volatile("" : : : "memory"); 3577 } 3578 3579 /* 3580 * Get address of the pointer variable in the main program. 3581 * Prefer non-weak symbol over the weak one. 3582 */ 3583 static const void ** 3584 get_program_var_addr(const char *name, RtldLockState *lockstate) 3585 { 3586 SymLook req; 3587 DoneList donelist; 3588 3589 symlook_init(&req, name); 3590 req.lockstate = lockstate; 3591 donelist_init(&donelist); 3592 if (symlook_global(&req, &donelist) != 0) 3593 return (NULL); 3594 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 3595 return ((const void **)make_function_pointer(req.sym_out, 3596 req.defobj_out)); 3597 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 3598 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 3599 else 3600 return ((const void **)(req.defobj_out->relocbase + 3601 req.sym_out->st_value)); 3602 } 3603 3604 /* 3605 * Set a pointer variable in the main program to the given value. This 3606 * is used to set key variables such as "environ" before any of the 3607 * init functions are called. 3608 */ 3609 static void 3610 set_program_var(const char *name, const void *value) 3611 { 3612 const void **addr; 3613 3614 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 3615 dbg("\"%s\": *%p <-- %p", name, addr, value); 3616 *addr = value; 3617 } 3618 } 3619 3620 /* 3621 * Search the global objects, including dependencies and main object, 3622 * for the given symbol. 3623 */ 3624 static int 3625 symlook_global(SymLook *req, DoneList *donelist) 3626 { 3627 SymLook req1; 3628 const Objlist_Entry *elm; 3629 int res; 3630 3631 symlook_init_from_req(&req1, req); 3632 3633 /* Search all objects loaded at program start up. */ 3634 if (req->defobj_out == NULL || 3635 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3636 res = symlook_list(&req1, &list_main, donelist); 3637 if (res == 0 && (req->defobj_out == NULL || 3638 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3639 req->sym_out = req1.sym_out; 3640 req->defobj_out = req1.defobj_out; 3641 assert(req->defobj_out != NULL); 3642 } 3643 } 3644 3645 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 3646 STAILQ_FOREACH(elm, &list_global, link) { 3647 if (req->defobj_out != NULL && 3648 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3649 break; 3650 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 3651 if (res == 0 && (req->defobj_out == NULL || 3652 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3653 req->sym_out = req1.sym_out; 3654 req->defobj_out = req1.defobj_out; 3655 assert(req->defobj_out != NULL); 3656 } 3657 } 3658 3659 return (req->sym_out != NULL ? 0 : ESRCH); 3660 } 3661 3662 /* 3663 * This is a special version of getenv which is far more efficient 3664 * at finding LD_ environment vars. 3665 */ 3666 static 3667 const char * 3668 _getenv_ld(const char *id) 3669 { 3670 const char *envp; 3671 int i, j; 3672 int idlen = strlen(id); 3673 3674 if (ld_index == LD_ARY_CACHE) 3675 return(getenv(id)); 3676 if (ld_index == 0) { 3677 for (i = j = 0; (envp = environ[i]) != NULL && j < LD_ARY_CACHE; ++i) { 3678 if (envp[0] == 'L' && envp[1] == 'D' && envp[2] == '_') 3679 ld_ary[j++] = envp; 3680 } 3681 if (j == 0) 3682 ld_ary[j++] = ""; 3683 ld_index = j; 3684 } 3685 for (i = ld_index - 1; i >= 0; --i) { 3686 if (strncmp(ld_ary[i], id, idlen) == 0 && ld_ary[i][idlen] == '=') 3687 return(ld_ary[i] + idlen + 1); 3688 } 3689 return(NULL); 3690 } 3691 3692 /* 3693 * Given a symbol name in a referencing object, find the corresponding 3694 * definition of the symbol. Returns a pointer to the symbol, or NULL if 3695 * no definition was found. Returns a pointer to the Obj_Entry of the 3696 * defining object via the reference parameter DEFOBJ_OUT. 3697 */ 3698 static int 3699 symlook_default(SymLook *req, const Obj_Entry *refobj) 3700 { 3701 DoneList donelist; 3702 const Objlist_Entry *elm; 3703 SymLook req1; 3704 int res; 3705 3706 donelist_init(&donelist); 3707 symlook_init_from_req(&req1, req); 3708 3709 /* Look first in the referencing object if linked symbolically. */ 3710 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 3711 res = symlook_obj(&req1, refobj); 3712 if (res == 0) { 3713 req->sym_out = req1.sym_out; 3714 req->defobj_out = req1.defobj_out; 3715 assert(req->defobj_out != NULL); 3716 } 3717 } 3718 3719 symlook_global(req, &donelist); 3720 3721 /* Search all dlopened DAGs containing the referencing object. */ 3722 STAILQ_FOREACH(elm, &refobj->dldags, link) { 3723 if (req->sym_out != NULL && 3724 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3725 break; 3726 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 3727 if (res == 0 && (req->sym_out == NULL || 3728 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3729 req->sym_out = req1.sym_out; 3730 req->defobj_out = req1.defobj_out; 3731 assert(req->defobj_out != NULL); 3732 } 3733 } 3734 3735 /* 3736 * Search the dynamic linker itself, and possibly resolve the 3737 * symbol from there. This is how the application links to 3738 * dynamic linker services such as dlopen. 3739 */ 3740 if (req->sym_out == NULL || 3741 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3742 res = symlook_obj(&req1, &obj_rtld); 3743 if (res == 0) { 3744 req->sym_out = req1.sym_out; 3745 req->defobj_out = req1.defobj_out; 3746 assert(req->defobj_out != NULL); 3747 } 3748 } 3749 3750 return (req->sym_out != NULL ? 0 : ESRCH); 3751 } 3752 3753 static int 3754 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 3755 { 3756 const Elf_Sym *def; 3757 const Obj_Entry *defobj; 3758 const Objlist_Entry *elm; 3759 SymLook req1; 3760 int res; 3761 3762 def = NULL; 3763 defobj = NULL; 3764 STAILQ_FOREACH(elm, objlist, link) { 3765 if (donelist_check(dlp, elm->obj)) 3766 continue; 3767 symlook_init_from_req(&req1, req); 3768 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 3769 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3770 def = req1.sym_out; 3771 defobj = req1.defobj_out; 3772 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3773 break; 3774 } 3775 } 3776 } 3777 if (def != NULL) { 3778 req->sym_out = def; 3779 req->defobj_out = defobj; 3780 return (0); 3781 } 3782 return (ESRCH); 3783 } 3784 3785 /* 3786 * Search the chain of DAGS cointed to by the given Needed_Entry 3787 * for a symbol of the given name. Each DAG is scanned completely 3788 * before advancing to the next one. Returns a pointer to the symbol, 3789 * or NULL if no definition was found. 3790 */ 3791 static int 3792 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 3793 { 3794 const Elf_Sym *def; 3795 const Needed_Entry *n; 3796 const Obj_Entry *defobj; 3797 SymLook req1; 3798 int res; 3799 3800 def = NULL; 3801 defobj = NULL; 3802 symlook_init_from_req(&req1, req); 3803 for (n = needed; n != NULL; n = n->next) { 3804 if (n->obj == NULL || 3805 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 3806 continue; 3807 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3808 def = req1.sym_out; 3809 defobj = req1.defobj_out; 3810 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3811 break; 3812 } 3813 } 3814 if (def != NULL) { 3815 req->sym_out = def; 3816 req->defobj_out = defobj; 3817 return (0); 3818 } 3819 return (ESRCH); 3820 } 3821 3822 /* 3823 * Search the symbol table of a single shared object for a symbol of 3824 * the given name and version, if requested. Returns a pointer to the 3825 * symbol, or NULL if no definition was found. If the object is 3826 * filter, return filtered symbol from filtee. 3827 * 3828 * The symbol's hash value is passed in for efficiency reasons; that 3829 * eliminates many recomputations of the hash value. 3830 */ 3831 int 3832 symlook_obj(SymLook *req, const Obj_Entry *obj) 3833 { 3834 DoneList donelist; 3835 SymLook req1; 3836 int flags, res, mres; 3837 3838 /* 3839 * If there is at least one valid hash at this point, we prefer to 3840 * use the faster GNU version if available. 3841 */ 3842 if (obj->valid_hash_gnu) 3843 mres = symlook_obj1_gnu(req, obj); 3844 else if (obj->valid_hash_sysv) 3845 mres = symlook_obj1_sysv(req, obj); 3846 else 3847 return (EINVAL); 3848 3849 if (mres == 0) { 3850 if (obj->needed_filtees != NULL) { 3851 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3852 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3853 donelist_init(&donelist); 3854 symlook_init_from_req(&req1, req); 3855 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 3856 if (res == 0) { 3857 req->sym_out = req1.sym_out; 3858 req->defobj_out = req1.defobj_out; 3859 } 3860 return (res); 3861 } 3862 if (obj->needed_aux_filtees != NULL) { 3863 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3864 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3865 donelist_init(&donelist); 3866 symlook_init_from_req(&req1, req); 3867 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 3868 if (res == 0) { 3869 req->sym_out = req1.sym_out; 3870 req->defobj_out = req1.defobj_out; 3871 return (res); 3872 } 3873 } 3874 } 3875 return (mres); 3876 } 3877 3878 /* Symbol match routine common to both hash functions */ 3879 static bool 3880 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 3881 const unsigned long symnum) 3882 { 3883 Elf_Versym verndx; 3884 const Elf_Sym *symp; 3885 const char *strp; 3886 3887 symp = obj->symtab + symnum; 3888 strp = obj->strtab + symp->st_name; 3889 3890 switch (ELF_ST_TYPE(symp->st_info)) { 3891 case STT_FUNC: 3892 case STT_NOTYPE: 3893 case STT_OBJECT: 3894 case STT_COMMON: 3895 case STT_GNU_IFUNC: 3896 if (symp->st_value == 0) 3897 return (false); 3898 /* fallthrough */ 3899 case STT_TLS: 3900 if (symp->st_shndx != SHN_UNDEF) 3901 break; 3902 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 3903 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 3904 break; 3905 /* fallthrough */ 3906 default: 3907 return (false); 3908 } 3909 if (strcmp(req->name, strp) != 0) 3910 return (false); 3911 3912 if (req->ventry == NULL) { 3913 if (obj->versyms != NULL) { 3914 verndx = VER_NDX(obj->versyms[symnum]); 3915 if (verndx > obj->vernum) { 3916 _rtld_error( 3917 "%s: symbol %s references wrong version %d", 3918 obj->path, obj->strtab + symnum, verndx); 3919 return (false); 3920 } 3921 /* 3922 * If we are not called from dlsym (i.e. this 3923 * is a normal relocation from unversioned 3924 * binary), accept the symbol immediately if 3925 * it happens to have first version after this 3926 * shared object became versioned. Otherwise, 3927 * if symbol is versioned and not hidden, 3928 * remember it. If it is the only symbol with 3929 * this name exported by the shared object, it 3930 * will be returned as a match by the calling 3931 * function. If symbol is global (verndx < 2) 3932 * accept it unconditionally. 3933 */ 3934 if ((req->flags & SYMLOOK_DLSYM) == 0 && 3935 verndx == VER_NDX_GIVEN) { 3936 result->sym_out = symp; 3937 return (true); 3938 } 3939 else if (verndx >= VER_NDX_GIVEN) { 3940 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 3941 == 0) { 3942 if (result->vsymp == NULL) 3943 result->vsymp = symp; 3944 result->vcount++; 3945 } 3946 return (false); 3947 } 3948 } 3949 result->sym_out = symp; 3950 return (true); 3951 } 3952 if (obj->versyms == NULL) { 3953 if (object_match_name(obj, req->ventry->name)) { 3954 _rtld_error("%s: object %s should provide version %s " 3955 "for symbol %s", obj_rtld.path, obj->path, 3956 req->ventry->name, obj->strtab + symnum); 3957 return (false); 3958 } 3959 } else { 3960 verndx = VER_NDX(obj->versyms[symnum]); 3961 if (verndx > obj->vernum) { 3962 _rtld_error("%s: symbol %s references wrong version %d", 3963 obj->path, obj->strtab + symnum, verndx); 3964 return (false); 3965 } 3966 if (obj->vertab[verndx].hash != req->ventry->hash || 3967 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 3968 /* 3969 * Version does not match. Look if this is a 3970 * global symbol and if it is not hidden. If 3971 * global symbol (verndx < 2) is available, 3972 * use it. Do not return symbol if we are 3973 * called by dlvsym, because dlvsym looks for 3974 * a specific version and default one is not 3975 * what dlvsym wants. 3976 */ 3977 if ((req->flags & SYMLOOK_DLSYM) || 3978 (verndx >= VER_NDX_GIVEN) || 3979 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 3980 return (false); 3981 } 3982 } 3983 result->sym_out = symp; 3984 return (true); 3985 } 3986 3987 /* 3988 * Search for symbol using SysV hash function. 3989 * obj->buckets is known not to be NULL at this point; the test for this was 3990 * performed with the obj->valid_hash_sysv assignment. 3991 */ 3992 static int 3993 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 3994 { 3995 unsigned long symnum; 3996 Sym_Match_Result matchres; 3997 3998 matchres.sym_out = NULL; 3999 matchres.vsymp = NULL; 4000 matchres.vcount = 0; 4001 4002 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4003 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4004 if (symnum >= obj->nchains) 4005 return (ESRCH); /* Bad object */ 4006 4007 if (matched_symbol(req, obj, &matchres, symnum)) { 4008 req->sym_out = matchres.sym_out; 4009 req->defobj_out = obj; 4010 return (0); 4011 } 4012 } 4013 if (matchres.vcount == 1) { 4014 req->sym_out = matchres.vsymp; 4015 req->defobj_out = obj; 4016 return (0); 4017 } 4018 return (ESRCH); 4019 } 4020 4021 /* Search for symbol using GNU hash function */ 4022 static int 4023 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4024 { 4025 Elf_Addr bloom_word; 4026 const Elf32_Word *hashval; 4027 Elf32_Word bucket; 4028 Sym_Match_Result matchres; 4029 unsigned int h1, h2; 4030 unsigned long symnum; 4031 4032 matchres.sym_out = NULL; 4033 matchres.vsymp = NULL; 4034 matchres.vcount = 0; 4035 4036 /* Pick right bitmask word from Bloom filter array */ 4037 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4038 obj->maskwords_bm_gnu]; 4039 4040 /* Calculate modulus word size of gnu hash and its derivative */ 4041 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4042 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4043 4044 /* Filter out the "definitely not in set" queries */ 4045 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4046 return (ESRCH); 4047 4048 /* Locate hash chain and corresponding value element*/ 4049 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4050 if (bucket == 0) 4051 return (ESRCH); 4052 hashval = &obj->chain_zero_gnu[bucket]; 4053 do { 4054 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4055 symnum = hashval - obj->chain_zero_gnu; 4056 if (matched_symbol(req, obj, &matchres, symnum)) { 4057 req->sym_out = matchres.sym_out; 4058 req->defobj_out = obj; 4059 return (0); 4060 } 4061 } 4062 } while ((*hashval++ & 1) == 0); 4063 if (matchres.vcount == 1) { 4064 req->sym_out = matchres.vsymp; 4065 req->defobj_out = obj; 4066 return (0); 4067 } 4068 return (ESRCH); 4069 } 4070 4071 static void 4072 trace_loaded_objects(Obj_Entry *obj) 4073 { 4074 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4075 int c; 4076 4077 if ((main_local = _getenv_ld("LD_TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 4078 main_local = ""; 4079 4080 if ((fmt1 = _getenv_ld("LD_TRACE_LOADED_OBJECTS_FMT1")) == NULL) 4081 fmt1 = "\t%o => %p (%x)\n"; 4082 4083 if ((fmt2 = _getenv_ld("LD_TRACE_LOADED_OBJECTS_FMT2")) == NULL) 4084 fmt2 = "\t%o (%x)\n"; 4085 4086 list_containers = _getenv_ld("LD_TRACE_LOADED_OBJECTS_ALL"); 4087 4088 for (; obj; obj = obj->next) { 4089 Needed_Entry *needed; 4090 char *name, *path; 4091 bool is_lib; 4092 4093 if (list_containers && obj->needed != NULL) 4094 rtld_printf("%s:\n", obj->path); 4095 for (needed = obj->needed; needed; needed = needed->next) { 4096 if (needed->obj != NULL) { 4097 if (needed->obj->traced && !list_containers) 4098 continue; 4099 needed->obj->traced = true; 4100 path = needed->obj->path; 4101 } else 4102 path = "not found"; 4103 4104 name = (char *)obj->strtab + needed->name; 4105 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4106 4107 fmt = is_lib ? fmt1 : fmt2; 4108 while ((c = *fmt++) != '\0') { 4109 switch (c) { 4110 default: 4111 rtld_putchar(c); 4112 continue; 4113 case '\\': 4114 switch (c = *fmt) { 4115 case '\0': 4116 continue; 4117 case 'n': 4118 rtld_putchar('\n'); 4119 break; 4120 case 't': 4121 rtld_putchar('\t'); 4122 break; 4123 } 4124 break; 4125 case '%': 4126 switch (c = *fmt) { 4127 case '\0': 4128 continue; 4129 case '%': 4130 default: 4131 rtld_putchar(c); 4132 break; 4133 case 'A': 4134 rtld_putstr(main_local); 4135 break; 4136 case 'a': 4137 rtld_putstr(obj_main->path); 4138 break; 4139 case 'o': 4140 rtld_putstr(name); 4141 break; 4142 case 'p': 4143 rtld_putstr(path); 4144 break; 4145 case 'x': 4146 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4147 0); 4148 break; 4149 } 4150 break; 4151 } 4152 ++fmt; 4153 } 4154 } 4155 } 4156 } 4157 4158 /* 4159 * Unload a dlopened object and its dependencies from memory and from 4160 * our data structures. It is assumed that the DAG rooted in the 4161 * object has already been unreferenced, and that the object has a 4162 * reference count of 0. 4163 */ 4164 static void 4165 unload_object(Obj_Entry *root) 4166 { 4167 Obj_Entry *obj; 4168 Obj_Entry **linkp; 4169 4170 assert(root->refcount == 0); 4171 4172 /* 4173 * Pass over the DAG removing unreferenced objects from 4174 * appropriate lists. 4175 */ 4176 unlink_object(root); 4177 4178 /* Unmap all objects that are no longer referenced. */ 4179 linkp = &obj_list->next; 4180 while ((obj = *linkp) != NULL) { 4181 if (obj->refcount == 0) { 4182 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 4183 obj->path); 4184 dbg("unloading \"%s\"", obj->path); 4185 unload_filtees(root); 4186 munmap(obj->mapbase, obj->mapsize); 4187 linkmap_delete(obj); 4188 *linkp = obj->next; 4189 obj_count--; 4190 obj_free(obj); 4191 } else 4192 linkp = &obj->next; 4193 } 4194 obj_tail = linkp; 4195 } 4196 4197 static void 4198 unlink_object(Obj_Entry *root) 4199 { 4200 Objlist_Entry *elm; 4201 4202 if (root->refcount == 0) { 4203 /* Remove the object from the RTLD_GLOBAL list. */ 4204 objlist_remove(&list_global, root); 4205 4206 /* Remove the object from all objects' DAG lists. */ 4207 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4208 objlist_remove(&elm->obj->dldags, root); 4209 if (elm->obj != root) 4210 unlink_object(elm->obj); 4211 } 4212 } 4213 } 4214 4215 static void 4216 ref_dag(Obj_Entry *root) 4217 { 4218 Objlist_Entry *elm; 4219 4220 assert(root->dag_inited); 4221 STAILQ_FOREACH(elm, &root->dagmembers, link) 4222 elm->obj->refcount++; 4223 } 4224 4225 static void 4226 unref_dag(Obj_Entry *root) 4227 { 4228 Objlist_Entry *elm; 4229 4230 assert(root->dag_inited); 4231 STAILQ_FOREACH(elm, &root->dagmembers, link) 4232 elm->obj->refcount--; 4233 } 4234 4235 /* 4236 * Common code for MD __tls_get_addr(). 4237 */ 4238 void * 4239 tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset) 4240 { 4241 Elf_Addr* dtv = *dtvp; 4242 RtldLockState lockstate; 4243 4244 /* Check dtv generation in case new modules have arrived */ 4245 if (dtv[0] != tls_dtv_generation) { 4246 Elf_Addr* newdtv; 4247 int to_copy; 4248 4249 wlock_acquire(rtld_bind_lock, &lockstate); 4250 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4251 to_copy = dtv[1]; 4252 if (to_copy > tls_max_index) 4253 to_copy = tls_max_index; 4254 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4255 newdtv[0] = tls_dtv_generation; 4256 newdtv[1] = tls_max_index; 4257 free(dtv); 4258 lock_release(rtld_bind_lock, &lockstate); 4259 dtv = *dtvp = newdtv; 4260 } 4261 4262 /* Dynamically allocate module TLS if necessary */ 4263 if (!dtv[index + 1]) { 4264 /* Signal safe, wlock will block out signals. */ 4265 wlock_acquire(rtld_bind_lock, &lockstate); 4266 if (!dtv[index + 1]) 4267 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4268 lock_release(rtld_bind_lock, &lockstate); 4269 } 4270 return (void*) (dtv[index + 1] + offset); 4271 } 4272 4273 #if defined(RTLD_STATIC_TLS_VARIANT_II) 4274 4275 /* 4276 * Allocate the static TLS area. Return a pointer to the TCB. The 4277 * static area is based on negative offsets relative to the tcb. 4278 * 4279 * The TCB contains an errno pointer for the system call layer, but because 4280 * we are the RTLD we really have no idea how the caller was compiled so 4281 * the information has to be passed in. errno can either be: 4282 * 4283 * type 0 errno is a simple non-TLS global pointer. 4284 * (special case for e.g. libc_rtld) 4285 * type 1 errno accessed by GOT entry (dynamically linked programs) 4286 * type 2 errno accessed by %gs:OFFSET (statically linked programs) 4287 */ 4288 struct tls_tcb * 4289 allocate_tls(Obj_Entry *objs) 4290 { 4291 Obj_Entry *obj; 4292 size_t data_size; 4293 size_t dtv_size; 4294 struct tls_tcb *tcb; 4295 Elf_Addr *dtv; 4296 Elf_Addr addr; 4297 4298 /* 4299 * Allocate the new TCB. static TLS storage is placed just before the 4300 * TCB to support the %gs:OFFSET (negative offset) model. 4301 */ 4302 data_size = (tls_static_space + RTLD_STATIC_TLS_ALIGN_MASK) & 4303 ~RTLD_STATIC_TLS_ALIGN_MASK; 4304 tcb = malloc(data_size + sizeof(*tcb)); 4305 tcb = (void *)((char *)tcb + data_size); /* actual tcb location */ 4306 4307 dtv_size = (tls_max_index + 2) * sizeof(Elf_Addr); 4308 dtv = malloc(dtv_size); 4309 bzero(dtv, dtv_size); 4310 4311 #ifdef RTLD_TCB_HAS_SELF_POINTER 4312 tcb->tcb_self = tcb; 4313 #endif 4314 tcb->tcb_dtv = dtv; 4315 tcb->tcb_pthread = NULL; 4316 4317 dtv[0] = tls_dtv_generation; 4318 dtv[1] = tls_max_index; 4319 4320 for (obj = objs; obj; obj = obj->next) { 4321 if (obj->tlsoffset) { 4322 addr = (Elf_Addr)tcb - obj->tlsoffset; 4323 memset((void *)(addr + obj->tlsinitsize), 4324 0, obj->tlssize - obj->tlsinitsize); 4325 if (obj->tlsinit) 4326 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4327 dtv[obj->tlsindex + 1] = addr; 4328 } 4329 } 4330 return(tcb); 4331 } 4332 4333 void 4334 free_tls(struct tls_tcb *tcb) 4335 { 4336 Elf_Addr *dtv; 4337 int dtv_size, i; 4338 Elf_Addr tls_start, tls_end; 4339 size_t data_size; 4340 4341 data_size = (tls_static_space + RTLD_STATIC_TLS_ALIGN_MASK) & 4342 ~RTLD_STATIC_TLS_ALIGN_MASK; 4343 4344 dtv = tcb->tcb_dtv; 4345 dtv_size = dtv[1]; 4346 tls_end = (Elf_Addr)tcb; 4347 tls_start = (Elf_Addr)tcb - data_size; 4348 for (i = 0; i < dtv_size; i++) { 4349 if (dtv[i+2] != 0 && (dtv[i+2] < tls_start || dtv[i+2] > tls_end)) { 4350 free((void *)dtv[i+2]); 4351 } 4352 } 4353 4354 free((void*) tls_start); 4355 } 4356 4357 #else 4358 #error "Unsupported TLS layout" 4359 #endif 4360 4361 /* 4362 * Allocate TLS block for module with given index. 4363 */ 4364 void * 4365 allocate_module_tls(int index) 4366 { 4367 Obj_Entry* obj; 4368 char* p; 4369 4370 for (obj = obj_list; obj; obj = obj->next) { 4371 if (obj->tlsindex == index) 4372 break; 4373 } 4374 if (!obj) { 4375 _rtld_error("Can't find module with TLS index %d", index); 4376 die(); 4377 } 4378 4379 p = malloc(obj->tlssize); 4380 if (p == NULL) { 4381 _rtld_error("Cannot allocate TLS block for index %d", index); 4382 die(); 4383 } 4384 memcpy(p, obj->tlsinit, obj->tlsinitsize); 4385 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 4386 4387 return p; 4388 } 4389 4390 bool 4391 allocate_tls_offset(Obj_Entry *obj) 4392 { 4393 size_t off; 4394 4395 if (obj->tls_done) 4396 return true; 4397 4398 if (obj->tlssize == 0) { 4399 obj->tls_done = true; 4400 return true; 4401 } 4402 4403 if (obj->tlsindex == 1) 4404 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 4405 else 4406 off = calculate_tls_offset(tls_last_offset, tls_last_size, 4407 obj->tlssize, obj->tlsalign); 4408 4409 /* 4410 * If we have already fixed the size of the static TLS block, we 4411 * must stay within that size. When allocating the static TLS, we 4412 * leave a small amount of space spare to be used for dynamically 4413 * loading modules which use static TLS. 4414 */ 4415 if (tls_static_space) { 4416 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 4417 return false; 4418 } 4419 4420 tls_last_offset = obj->tlsoffset = off; 4421 tls_last_size = obj->tlssize; 4422 obj->tls_done = true; 4423 4424 return true; 4425 } 4426 4427 void 4428 free_tls_offset(Obj_Entry *obj) 4429 { 4430 #ifdef RTLD_STATIC_TLS_VARIANT_II 4431 /* 4432 * If we were the last thing to allocate out of the static TLS 4433 * block, we give our space back to the 'allocator'. This is a 4434 * simplistic workaround to allow libGL.so.1 to be loaded and 4435 * unloaded multiple times. We only handle the Variant II 4436 * mechanism for now - this really needs a proper allocator. 4437 */ 4438 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 4439 == calculate_tls_end(tls_last_offset, tls_last_size)) { 4440 tls_last_offset -= obj->tlssize; 4441 tls_last_size = 0; 4442 } 4443 #endif 4444 } 4445 4446 struct tls_tcb * 4447 _rtld_allocate_tls(void) 4448 { 4449 struct tls_tcb *new_tcb; 4450 RtldLockState lockstate; 4451 4452 wlock_acquire(rtld_bind_lock, &lockstate); 4453 new_tcb = allocate_tls(obj_list); 4454 lock_release(rtld_bind_lock, &lockstate); 4455 return (new_tcb); 4456 } 4457 4458 void 4459 _rtld_free_tls(struct tls_tcb *tcb) 4460 { 4461 RtldLockState lockstate; 4462 4463 wlock_acquire(rtld_bind_lock, &lockstate); 4464 free_tls(tcb); 4465 lock_release(rtld_bind_lock, &lockstate); 4466 } 4467 4468 static void 4469 object_add_name(Obj_Entry *obj, const char *name) 4470 { 4471 Name_Entry *entry; 4472 size_t len; 4473 4474 len = strlen(name); 4475 entry = malloc(sizeof(Name_Entry) + len); 4476 4477 if (entry != NULL) { 4478 strcpy(entry->name, name); 4479 STAILQ_INSERT_TAIL(&obj->names, entry, link); 4480 } 4481 } 4482 4483 static int 4484 object_match_name(const Obj_Entry *obj, const char *name) 4485 { 4486 Name_Entry *entry; 4487 4488 STAILQ_FOREACH(entry, &obj->names, link) { 4489 if (strcmp(name, entry->name) == 0) 4490 return (1); 4491 } 4492 return (0); 4493 } 4494 4495 static Obj_Entry * 4496 locate_dependency(const Obj_Entry *obj, const char *name) 4497 { 4498 const Objlist_Entry *entry; 4499 const Needed_Entry *needed; 4500 4501 STAILQ_FOREACH(entry, &list_main, link) { 4502 if (object_match_name(entry->obj, name)) 4503 return entry->obj; 4504 } 4505 4506 for (needed = obj->needed; needed != NULL; needed = needed->next) { 4507 if (strcmp(obj->strtab + needed->name, name) == 0 || 4508 (needed->obj != NULL && object_match_name(needed->obj, name))) { 4509 /* 4510 * If there is DT_NEEDED for the name we are looking for, 4511 * we are all set. Note that object might not be found if 4512 * dependency was not loaded yet, so the function can 4513 * return NULL here. This is expected and handled 4514 * properly by the caller. 4515 */ 4516 return (needed->obj); 4517 } 4518 } 4519 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 4520 obj->path, name); 4521 die(); 4522 } 4523 4524 static int 4525 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 4526 const Elf_Vernaux *vna) 4527 { 4528 const Elf_Verdef *vd; 4529 const char *vername; 4530 4531 vername = refobj->strtab + vna->vna_name; 4532 vd = depobj->verdef; 4533 if (vd == NULL) { 4534 _rtld_error("%s: version %s required by %s not defined", 4535 depobj->path, vername, refobj->path); 4536 return (-1); 4537 } 4538 for (;;) { 4539 if (vd->vd_version != VER_DEF_CURRENT) { 4540 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4541 depobj->path, vd->vd_version); 4542 return (-1); 4543 } 4544 if (vna->vna_hash == vd->vd_hash) { 4545 const Elf_Verdaux *aux = (const Elf_Verdaux *) 4546 ((char *)vd + vd->vd_aux); 4547 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 4548 return (0); 4549 } 4550 if (vd->vd_next == 0) 4551 break; 4552 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4553 } 4554 if (vna->vna_flags & VER_FLG_WEAK) 4555 return (0); 4556 _rtld_error("%s: version %s required by %s not found", 4557 depobj->path, vername, refobj->path); 4558 return (-1); 4559 } 4560 4561 static int 4562 rtld_verify_object_versions(Obj_Entry *obj) 4563 { 4564 const Elf_Verneed *vn; 4565 const Elf_Verdef *vd; 4566 const Elf_Verdaux *vda; 4567 const Elf_Vernaux *vna; 4568 const Obj_Entry *depobj; 4569 int maxvernum, vernum; 4570 4571 if (obj->ver_checked) 4572 return (0); 4573 obj->ver_checked = true; 4574 4575 maxvernum = 0; 4576 /* 4577 * Walk over defined and required version records and figure out 4578 * max index used by any of them. Do very basic sanity checking 4579 * while there. 4580 */ 4581 vn = obj->verneed; 4582 while (vn != NULL) { 4583 if (vn->vn_version != VER_NEED_CURRENT) { 4584 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 4585 obj->path, vn->vn_version); 4586 return (-1); 4587 } 4588 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4589 for (;;) { 4590 vernum = VER_NEED_IDX(vna->vna_other); 4591 if (vernum > maxvernum) 4592 maxvernum = vernum; 4593 if (vna->vna_next == 0) 4594 break; 4595 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4596 } 4597 if (vn->vn_next == 0) 4598 break; 4599 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4600 } 4601 4602 vd = obj->verdef; 4603 while (vd != NULL) { 4604 if (vd->vd_version != VER_DEF_CURRENT) { 4605 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4606 obj->path, vd->vd_version); 4607 return (-1); 4608 } 4609 vernum = VER_DEF_IDX(vd->vd_ndx); 4610 if (vernum > maxvernum) 4611 maxvernum = vernum; 4612 if (vd->vd_next == 0) 4613 break; 4614 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4615 } 4616 4617 if (maxvernum == 0) 4618 return (0); 4619 4620 /* 4621 * Store version information in array indexable by version index. 4622 * Verify that object version requirements are satisfied along the 4623 * way. 4624 */ 4625 obj->vernum = maxvernum + 1; 4626 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 4627 4628 vd = obj->verdef; 4629 while (vd != NULL) { 4630 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 4631 vernum = VER_DEF_IDX(vd->vd_ndx); 4632 assert(vernum <= maxvernum); 4633 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 4634 obj->vertab[vernum].hash = vd->vd_hash; 4635 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 4636 obj->vertab[vernum].file = NULL; 4637 obj->vertab[vernum].flags = 0; 4638 } 4639 if (vd->vd_next == 0) 4640 break; 4641 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4642 } 4643 4644 vn = obj->verneed; 4645 while (vn != NULL) { 4646 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 4647 if (depobj == NULL) 4648 return (-1); 4649 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4650 for (;;) { 4651 if (check_object_provided_version(obj, depobj, vna)) 4652 return (-1); 4653 vernum = VER_NEED_IDX(vna->vna_other); 4654 assert(vernum <= maxvernum); 4655 obj->vertab[vernum].hash = vna->vna_hash; 4656 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 4657 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 4658 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 4659 VER_INFO_HIDDEN : 0; 4660 if (vna->vna_next == 0) 4661 break; 4662 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4663 } 4664 if (vn->vn_next == 0) 4665 break; 4666 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4667 } 4668 return 0; 4669 } 4670 4671 static int 4672 rtld_verify_versions(const Objlist *objlist) 4673 { 4674 Objlist_Entry *entry; 4675 int rc; 4676 4677 rc = 0; 4678 STAILQ_FOREACH(entry, objlist, link) { 4679 /* 4680 * Skip dummy objects or objects that have their version requirements 4681 * already checked. 4682 */ 4683 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 4684 continue; 4685 if (rtld_verify_object_versions(entry->obj) == -1) { 4686 rc = -1; 4687 if (ld_tracing == NULL) 4688 break; 4689 } 4690 } 4691 if (rc == 0 || ld_tracing != NULL) 4692 rc = rtld_verify_object_versions(&obj_rtld); 4693 return rc; 4694 } 4695 4696 const Ver_Entry * 4697 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 4698 { 4699 Elf_Versym vernum; 4700 4701 if (obj->vertab) { 4702 vernum = VER_NDX(obj->versyms[symnum]); 4703 if (vernum >= obj->vernum) { 4704 _rtld_error("%s: symbol %s has wrong verneed value %d", 4705 obj->path, obj->strtab + symnum, vernum); 4706 } else if (obj->vertab[vernum].hash != 0) { 4707 return &obj->vertab[vernum]; 4708 } 4709 } 4710 return NULL; 4711 } 4712 4713 int 4714 _rtld_get_stack_prot(void) 4715 { 4716 4717 return (stack_prot); 4718 } 4719 4720 static void 4721 map_stacks_exec(RtldLockState *lockstate) 4722 { 4723 return; 4724 /* 4725 * Stack protection must be implemented in the kernel before the dynamic 4726 * linker can handle PT_GNU_STACK sections. 4727 * The following is the FreeBSD implementation of map_stacks_exec() 4728 * void (*thr_map_stacks_exec)(void); 4729 * 4730 * if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 4731 * return; 4732 * thr_map_stacks_exec = (void (*)(void))(uintptr_t) 4733 * get_program_var_addr("__pthread_map_stacks_exec", lockstate); 4734 * if (thr_map_stacks_exec != NULL) { 4735 * stack_prot |= PROT_EXEC; 4736 * thr_map_stacks_exec(); 4737 * } 4738 */ 4739 } 4740 4741 void 4742 symlook_init(SymLook *dst, const char *name) 4743 { 4744 4745 bzero(dst, sizeof(*dst)); 4746 dst->name = name; 4747 dst->hash = elf_hash(name); 4748 dst->hash_gnu = gnu_hash(name); 4749 } 4750 4751 static void 4752 symlook_init_from_req(SymLook *dst, const SymLook *src) 4753 { 4754 4755 dst->name = src->name; 4756 dst->hash = src->hash; 4757 dst->hash_gnu = src->hash_gnu; 4758 dst->ventry = src->ventry; 4759 dst->flags = src->flags; 4760 dst->defobj_out = NULL; 4761 dst->sym_out = NULL; 4762 dst->lockstate = src->lockstate; 4763 } 4764 4765 #ifdef ENABLE_OSRELDATE 4766 /* 4767 * Overrides for libc_pic-provided functions. 4768 */ 4769 4770 int 4771 __getosreldate(void) 4772 { 4773 size_t len; 4774 int oid[2]; 4775 int error, osrel; 4776 4777 if (osreldate != 0) 4778 return (osreldate); 4779 4780 oid[0] = CTL_KERN; 4781 oid[1] = KERN_OSRELDATE; 4782 osrel = 0; 4783 len = sizeof(osrel); 4784 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 4785 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 4786 osreldate = osrel; 4787 return (osreldate); 4788 } 4789 #endif 4790 4791 /* 4792 * No unresolved symbols for rtld. 4793 */ 4794 void 4795 __pthread_cxa_finalize(struct dl_phdr_info *a) 4796 { 4797 } 4798 4799 const char * 4800 rtld_strerror(int errnum) 4801 { 4802 4803 if (errnum < 0 || errnum >= sys_nerr) 4804 return ("Unknown error"); 4805 return (sys_errlist[errnum]); 4806 } 4807