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 bool is_exported(const Elf_Sym *); 104 static void linkmap_add(Obj_Entry *); 105 static void linkmap_delete(Obj_Entry *); 106 static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 107 static void unload_filtees(Obj_Entry *); 108 static int load_needed_objects(Obj_Entry *, int); 109 static int load_preload_objects(void); 110 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 111 static void map_stacks_exec(RtldLockState *); 112 static Obj_Entry *obj_from_addr(const void *); 113 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 114 static void objlist_call_init(Objlist *, RtldLockState *); 115 static void objlist_clear(Objlist *); 116 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 117 static void objlist_init(Objlist *); 118 static void objlist_push_head(Objlist *, Obj_Entry *); 119 static void objlist_push_tail(Objlist *, Obj_Entry *); 120 static void objlist_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 int origin_subst_one(char **, const char *, const char *, 150 const char *, char *); 151 static char *origin_subst(const char *, const char *); 152 static void preinitialize_main_object (void); 153 static int rtld_verify_versions(const Objlist *); 154 static int rtld_verify_object_versions(Obj_Entry *); 155 static void object_add_name(Obj_Entry *, const char *); 156 static int object_match_name(const Obj_Entry *, const char *); 157 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 158 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 159 struct dl_phdr_info *phdr_info); 160 static uint_fast32_t gnu_hash (const char *); 161 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 162 const unsigned long); 163 164 void r_debug_state(struct r_debug *, struct link_map *) __noinline; 165 166 /* 167 * Data declarations. 168 */ 169 static char *error_message; /* Message for dlerror(), or NULL */ 170 struct r_debug r_debug; /* for GDB; */ 171 static bool libmap_disable; /* Disable libmap */ 172 static bool ld_loadfltr; /* Immediate filters processing */ 173 static char *libmap_override; /* Maps to use in addition to libmap.conf */ 174 static bool trust; /* False for setuid and setgid programs */ 175 static bool dangerous_ld_env; /* True if environment variables have been 176 used to affect the libraries loaded */ 177 static const char *ld_bind_now; /* Environment variable for immediate binding */ 178 static const char *ld_debug; /* Environment variable for debugging */ 179 static const char *ld_library_path; /* Environment variable for search path */ 180 static char *ld_preload; /* Environment variable for libraries to 181 load first */ 182 static const char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 183 static const char *ld_tracing; /* Called from ldd to print libs */ 184 static const char *ld_utrace; /* Use utrace() to log events. */ 185 static int (*rtld_functrace)( /* Optional function call tracing hook */ 186 const char *caller_obj, 187 const char *callee_obj, 188 const char *callee_func, 189 void *stack); 190 static const Obj_Entry *rtld_functrace_obj; /* Object thereof */ 191 static Obj_Entry *obj_list; /* Head of linked list of shared objects */ 192 static Obj_Entry **obj_tail; /* Link field of last object in list */ 193 static Obj_Entry **preload_tail; 194 static Obj_Entry *obj_main; /* The main program shared object */ 195 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 196 static unsigned int obj_count; /* Number of objects in obj_list */ 197 static unsigned int obj_loads; /* Number of objects in obj_list */ 198 199 static int ld_resident; /* Non-zero if resident */ 200 static const char *ld_ary[LD_ARY_CACHE]; 201 static int ld_index; 202 static Objlist initlist; 203 204 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 205 STAILQ_HEAD_INITIALIZER(list_global); 206 static Objlist list_main = /* Objects loaded at program startup */ 207 STAILQ_HEAD_INITIALIZER(list_main); 208 static Objlist list_fini = /* Objects needing fini() calls */ 209 STAILQ_HEAD_INITIALIZER(list_fini); 210 211 static Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 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 * These are the functions the dynamic linker exports to application 230 * programs. They are the only symbols the dynamic linker is willing 231 * to export from itself. 232 */ 233 static func_ptr_type exports[] = { 234 (func_ptr_type) &_rtld_error, 235 (func_ptr_type) &dlclose, 236 (func_ptr_type) &dlerror, 237 (func_ptr_type) &dlopen, 238 (func_ptr_type) &fdlopen, 239 (func_ptr_type) &dlfunc, 240 (func_ptr_type) &dlsym, 241 (func_ptr_type) &dlvsym, 242 (func_ptr_type) &dladdr, 243 (func_ptr_type) &dlinfo, 244 (func_ptr_type) &dl_iterate_phdr, 245 #ifdef __i386__ 246 (func_ptr_type) &___tls_get_addr, 247 #endif 248 (func_ptr_type) &__tls_get_addr, 249 (func_ptr_type) &__tls_get_addr_tcb, 250 (func_ptr_type) &_rtld_allocate_tls, 251 (func_ptr_type) &_rtld_free_tls, 252 (func_ptr_type) &_rtld_call_init, 253 (func_ptr_type) &_rtld_thread_init, 254 (func_ptr_type) &_rtld_addr_phdr, 255 (func_ptr_type) &_rtld_get_stack_prot, 256 NULL 257 }; 258 259 /* 260 * Global declarations normally provided by crt1. The dynamic linker is 261 * not built with crt1, so we have to provide them ourselves. 262 */ 263 char *__progname; 264 char **environ; 265 266 /* 267 * Used to pass argc, argv to init functions. 268 */ 269 int main_argc; 270 char **main_argv; 271 272 /* 273 * Globals to control TLS allocation. 274 */ 275 size_t tls_last_offset; /* Static TLS offset of last module */ 276 size_t tls_last_size; /* Static TLS size of last module */ 277 size_t tls_static_space; /* Static TLS space allocated */ 278 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 279 int tls_max_index = 1; /* Largest module index allocated */ 280 281 /* 282 * Fill in a DoneList with an allocation large enough to hold all of 283 * the currently-loaded objects. Keep this as a macro since it calls 284 * alloca and we want that to occur within the scope of the caller. 285 */ 286 #define donelist_init(dlp) \ 287 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 288 assert((dlp)->objs != NULL), \ 289 (dlp)->num_alloc = obj_count, \ 290 (dlp)->num_used = 0) 291 292 #define UTRACE_DLOPEN_START 1 293 #define UTRACE_DLOPEN_STOP 2 294 #define UTRACE_DLCLOSE_START 3 295 #define UTRACE_DLCLOSE_STOP 4 296 #define UTRACE_LOAD_OBJECT 5 297 #define UTRACE_UNLOAD_OBJECT 6 298 #define UTRACE_ADD_RUNDEP 7 299 #define UTRACE_PRELOAD_FINISHED 8 300 #define UTRACE_INIT_CALL 9 301 #define UTRACE_FINI_CALL 10 302 303 struct utrace_rtld { 304 char sig[4]; /* 'RTLD' */ 305 int event; 306 void *handle; 307 void *mapbase; /* Used for 'parent' and 'init/fini' */ 308 size_t mapsize; 309 int refcnt; /* Used for 'mode' */ 310 char name[MAXPATHLEN]; 311 }; 312 313 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 314 if (ld_utrace != NULL) \ 315 ld_utrace_log(e, h, mb, ms, r, n); \ 316 } while (0) 317 318 static void 319 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 320 int refcnt, const char *name) 321 { 322 struct utrace_rtld ut; 323 324 ut.sig[0] = 'R'; 325 ut.sig[1] = 'T'; 326 ut.sig[2] = 'L'; 327 ut.sig[3] = 'D'; 328 ut.event = event; 329 ut.handle = handle; 330 ut.mapbase = mapbase; 331 ut.mapsize = mapsize; 332 ut.refcnt = refcnt; 333 bzero(ut.name, sizeof(ut.name)); 334 if (name) 335 strlcpy(ut.name, name, sizeof(ut.name)); 336 utrace(&ut, sizeof(ut)); 337 } 338 339 /* 340 * Main entry point for dynamic linking. The first argument is the 341 * stack pointer. The stack is expected to be laid out as described 342 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 343 * Specifically, the stack pointer points to a word containing 344 * ARGC. Following that in the stack is a null-terminated sequence 345 * of pointers to argument strings. Then comes a null-terminated 346 * sequence of pointers to environment strings. Finally, there is a 347 * sequence of "auxiliary vector" entries. 348 * 349 * The second argument points to a place to store the dynamic linker's 350 * exit procedure pointer and the third to a place to store the main 351 * program's object. 352 * 353 * The return value is the main program's entry point. 354 */ 355 func_ptr_type 356 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 357 { 358 Elf_Auxinfo *aux_info[AT_COUNT]; 359 int i; 360 int argc; 361 char **argv; 362 char **env; 363 Elf_Auxinfo *aux; 364 Elf_Auxinfo *auxp; 365 const char *argv0; 366 Objlist_Entry *entry; 367 Obj_Entry *obj; 368 369 /* marino: DO NOT MOVE THESE VARIABLES TO _rtld 370 Obj_Entry **preload_tail; 371 Objlist initlist; 372 from global to here. It will break the DWARF2 unwind scheme. 373 The system compilers were unaffected, but not gcc 4.6 374 */ 375 376 /* 377 * On entry, the dynamic linker itself has not been relocated yet. 378 * Be very careful not to reference any global data until after 379 * init_rtld has returned. It is OK to reference file-scope statics 380 * and string constants, and to call static and global functions. 381 */ 382 383 /* Find the auxiliary vector on the stack. */ 384 argc = *sp++; 385 argv = (char **) sp; 386 sp += argc + 1; /* Skip over arguments and NULL terminator */ 387 env = (char **) sp; 388 389 /* 390 * If we aren't already resident we have to dig out some more info. 391 * Note that auxinfo does not exist when we are resident. 392 * 393 * I'm not sure about the ld_resident check. It seems to read zero 394 * prior to relocation, which is what we want. When running from a 395 * resident copy everything will be relocated so we are definitely 396 * good there. 397 */ 398 if (ld_resident == 0) { 399 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 400 ; 401 aux = (Elf_Auxinfo *) sp; 402 403 /* Digest the auxiliary vector. */ 404 for (i = 0; i < AT_COUNT; i++) 405 aux_info[i] = NULL; 406 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 407 if (auxp->a_type < AT_COUNT) 408 aux_info[auxp->a_type] = auxp; 409 } 410 411 /* Initialize and relocate ourselves. */ 412 assert(aux_info[AT_BASE] != NULL); 413 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 414 } 415 416 ld_index = 0; /* don't use old env cache in case we are resident */ 417 __progname = obj_rtld.path; 418 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 419 environ = env; 420 main_argc = argc; 421 main_argv = argv; 422 423 trust = !issetugid(); 424 425 ld_bind_now = _getenv_ld("LD_BIND_NOW"); 426 /* 427 * If the process is tainted, then we un-set the dangerous environment 428 * variables. The process will be marked as tainted until setuid(2) 429 * is called. If any child process calls setuid(2) we do not want any 430 * future processes to honor the potentially un-safe variables. 431 */ 432 if (!trust) { 433 if ( unsetenv("LD_DEBUG") 434 || unsetenv("LD_PRELOAD") 435 || unsetenv("LD_LIBRARY_PATH") 436 || unsetenv("LD_ELF_HINTS_PATH") 437 || unsetenv("LD_LIBMAP") 438 || unsetenv("LD_LIBMAP_DISABLE") 439 || unsetenv("LD_LOADFLTR") 440 ) { 441 _rtld_error("environment corrupt; aborting"); 442 die(); 443 } 444 } 445 ld_debug = _getenv_ld("LD_DEBUG"); 446 libmap_disable = _getenv_ld("LD_LIBMAP_DISABLE") != NULL; 447 libmap_override = (char *)_getenv_ld("LD_LIBMAP"); 448 ld_library_path = _getenv_ld("LD_LIBRARY_PATH"); 449 ld_preload = (char *)_getenv_ld("LD_PRELOAD"); 450 ld_elf_hints_path = _getenv_ld("LD_ELF_HINTS_PATH"); 451 ld_loadfltr = _getenv_ld("LD_LOADFLTR") != NULL; 452 dangerous_ld_env = (ld_library_path != NULL) 453 || (ld_preload != NULL) 454 || (ld_elf_hints_path != NULL) 455 || ld_loadfltr 456 || (libmap_override != NULL) 457 || libmap_disable 458 ; 459 ld_tracing = _getenv_ld("LD_TRACE_LOADED_OBJECTS"); 460 ld_utrace = _getenv_ld("LD_UTRACE"); 461 462 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 463 ld_elf_hints_path = _PATH_ELF_HINTS; 464 465 if (ld_debug != NULL && *ld_debug != '\0') 466 debug = 1; 467 dbg("%s is initialized, base address = %p", __progname, 468 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 469 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 470 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 471 472 dbg("initializing thread locks"); 473 lockdflt_init(); 474 475 /* 476 * If we are resident we can skip work that we have already done. 477 * Note that the stack is reset and there is no Elf_Auxinfo 478 * when running from a resident image, and the static globals setup 479 * between here and resident_skip will have already been setup. 480 */ 481 if (ld_resident) 482 goto resident_skip1; 483 484 /* 485 * Load the main program, or process its program header if it is 486 * already loaded. 487 */ 488 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */ 489 int fd = aux_info[AT_EXECFD]->a_un.a_val; 490 dbg("loading main program"); 491 obj_main = map_object(fd, argv0, NULL); 492 close(fd); 493 if (obj_main == NULL) 494 die(); 495 max_stack_flags = obj->stack_flags; 496 } else { /* Main program already loaded. */ 497 const Elf_Phdr *phdr; 498 int phnum; 499 caddr_t entry; 500 501 dbg("processing main program's program header"); 502 assert(aux_info[AT_PHDR] != NULL); 503 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 504 assert(aux_info[AT_PHNUM] != NULL); 505 phnum = aux_info[AT_PHNUM]->a_un.a_val; 506 assert(aux_info[AT_PHENT] != NULL); 507 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 508 assert(aux_info[AT_ENTRY] != NULL); 509 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 510 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL) 511 die(); 512 } 513 514 char buf[MAXPATHLEN]; 515 if (aux_info[AT_EXECPATH] != NULL) { 516 char *kexecpath; 517 518 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 519 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 520 if (kexecpath[0] == '/') 521 obj_main->path = kexecpath; 522 else if (getcwd(buf, sizeof(buf)) == NULL || 523 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 524 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 525 obj_main->path = xstrdup(argv0); 526 else 527 obj_main->path = xstrdup(buf); 528 } else { 529 char resolved[MAXPATHLEN]; 530 dbg("No AT_EXECPATH"); 531 if (argv0[0] == '/') { 532 if (realpath(argv0, resolved) != NULL) 533 obj_main->path = xstrdup(resolved); 534 else 535 obj_main->path = xstrdup(argv0); 536 } else { 537 if (getcwd(buf, sizeof(buf)) != NULL 538 && strlcat(buf, "/", sizeof(buf)) < sizeof(buf) 539 && strlcat(buf, argv0, sizeof (buf)) < sizeof(buf) 540 && access(buf, R_OK) == 0 541 && realpath(buf, resolved) != NULL) 542 obj_main->path = xstrdup(resolved); 543 else 544 obj_main->path = xstrdup(argv0); 545 } 546 } 547 dbg("obj_main path %s", obj_main->path); 548 obj_main->mainprog = true; 549 550 if (aux_info[AT_STACKPROT] != NULL && 551 aux_info[AT_STACKPROT]->a_un.a_val != 0) 552 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 553 554 /* 555 * Get the actual dynamic linker pathname from the executable if 556 * possible. (It should always be possible.) That ensures that 557 * gdb will find the right dynamic linker even if a non-standard 558 * one is being used. 559 */ 560 if (obj_main->interp != NULL && 561 strcmp(obj_main->interp, obj_rtld.path) != 0) { 562 free(obj_rtld.path); 563 obj_rtld.path = xstrdup(obj_main->interp); 564 __progname = obj_rtld.path; 565 } 566 567 digest_dynamic(obj_main, 0); 568 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 569 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 570 obj_main->dynsymcount); 571 572 linkmap_add(obj_main); 573 linkmap_add(&obj_rtld); 574 575 /* Link the main program into the list of objects. */ 576 *obj_tail = obj_main; 577 obj_tail = &obj_main->next; 578 obj_count++; 579 obj_loads++; 580 581 /* Initialize a fake symbol for resolving undefined weak references. */ 582 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 583 sym_zero.st_shndx = SHN_UNDEF; 584 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 585 586 if (!libmap_disable) 587 libmap_disable = (bool)lm_init(libmap_override); 588 589 dbg("loading LD_PRELOAD libraries"); 590 if (load_preload_objects() == -1) 591 die(); 592 preload_tail = obj_tail; 593 594 dbg("loading needed objects"); 595 if (load_needed_objects(obj_main, 0) == -1) 596 die(); 597 598 /* Make a list of all objects loaded at startup. */ 599 for (obj = obj_list; obj != NULL; obj = obj->next) { 600 objlist_push_tail(&list_main, obj); 601 obj->refcount++; 602 } 603 604 dbg("checking for required versions"); 605 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 606 die(); 607 608 resident_skip1: 609 610 if (ld_tracing) { /* We're done */ 611 trace_loaded_objects(obj_main); 612 exit(0); 613 } 614 615 if (ld_resident) /* XXX clean this up! */ 616 goto resident_skip2; 617 618 if (_getenv_ld("LD_DUMP_REL_PRE") != NULL) { 619 dump_relocations(obj_main); 620 exit (0); 621 } 622 623 /* setup TLS for main thread */ 624 dbg("initializing initial thread local storage"); 625 STAILQ_FOREACH(entry, &list_main, link) { 626 /* 627 * Allocate all the initial objects out of the static TLS 628 * block even if they didn't ask for it. 629 */ 630 allocate_tls_offset(entry->obj); 631 } 632 633 tls_static_space = tls_last_offset + RTLD_STATIC_TLS_EXTRA; 634 635 /* 636 * Do not try to allocate the TLS here, let libc do it itself. 637 * (crt1 for the program will call _init_tls()) 638 */ 639 640 if (relocate_objects(obj_main, 641 ld_bind_now != NULL && *ld_bind_now != '\0', 642 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 643 die(); 644 645 dbg("doing copy relocations"); 646 if (do_copy_relocations(obj_main) == -1) 647 die(); 648 649 resident_skip2: 650 651 if (_getenv_ld("LD_RESIDENT_UNREGISTER_NOW")) { 652 if (exec_sys_unregister(-1) < 0) { 653 dbg("exec_sys_unregister failed %d\n", errno); 654 exit(errno); 655 } 656 dbg("exec_sys_unregister success\n"); 657 exit(0); 658 } 659 660 if (_getenv_ld("LD_DUMP_REL_POST") != NULL) { 661 dump_relocations(obj_main); 662 exit (0); 663 } 664 665 dbg("initializing key program variables"); 666 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 667 set_program_var("environ", env); 668 set_program_var("__elf_aux_vector", aux); 669 670 if (_getenv_ld("LD_RESIDENT_REGISTER_NOW")) { 671 extern void resident_start(void); 672 ld_resident = 1; 673 if (exec_sys_register(resident_start) < 0) { 674 dbg("exec_sys_register failed %d\n", errno); 675 exit(errno); 676 } 677 dbg("exec_sys_register success\n"); 678 exit(0); 679 } 680 681 /* Make a list of init functions to call. */ 682 objlist_init(&initlist); 683 initlist_add_objects(obj_list, preload_tail, &initlist); 684 685 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 686 687 map_stacks_exec(NULL); 688 689 dbg("resolving ifuncs"); 690 if (resolve_objects_ifunc(obj_main, 691 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY, 692 NULL) == -1) 693 die(); 694 695 /* 696 * Do NOT call the initlist here, give libc a chance to set up 697 * the initial TLS segment. crt1 will then call _rtld_call_init(). 698 */ 699 700 dbg("transferring control to program entry point = %p", obj_main->entry); 701 702 /* Return the exit procedure and the program entry point. */ 703 *exit_proc = rtld_exit; 704 *objp = obj_main; 705 return (func_ptr_type) obj_main->entry; 706 } 707 708 /* 709 * Call the initialization list for dynamically loaded libraries. 710 * (called from crt1.c). 711 */ 712 void 713 _rtld_call_init(void) 714 { 715 RtldLockState lockstate; 716 Obj_Entry *obj; 717 718 if (!obj_main->note_present && obj_main->valid_hash_gnu) { 719 /* 720 * The use of a linker script with a PHDRS directive that does not include 721 * PT_NOTE will block the crt_no_init note. In this case we'll look for the 722 * recently added GNU hash dynamic tag which gets built by default. It is 723 * extremely unlikely to find a pre-3.1 binary without a PT_NOTE header and 724 * a gnu hash tag. If gnu hash found, consider binary to use new crt code. 725 */ 726 obj_main->crt_no_init = true; 727 dbg("Setting crt_no_init without presence of PT_NOTE header"); 728 } 729 730 wlock_acquire(rtld_bind_lock, &lockstate); 731 if (obj_main->crt_no_init) { 732 preinitialize_main_object(); 733 } 734 else { 735 /* 736 * Make sure we don't call the main program's init and fini functions 737 * for binaries linked with old crt1 which calls _init itself. 738 */ 739 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 740 obj_main->init_array = obj_main->fini_array = (Elf_Addr)NULL; 741 } 742 objlist_call_init(&initlist, &lockstate); 743 objlist_clear(&initlist); 744 dbg("loading filtees"); 745 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 746 if (ld_loadfltr || obj->z_loadfltr) 747 load_filtees(obj, 0, &lockstate); 748 } 749 lock_release(rtld_bind_lock, &lockstate); 750 } 751 752 void * 753 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 754 { 755 void *ptr; 756 Elf_Addr target; 757 758 ptr = (void *)make_function_pointer(def, obj); 759 target = ((Elf_Addr (*)(void))ptr)(); 760 return ((void *)target); 761 } 762 763 Elf_Addr 764 _rtld_bind(Obj_Entry *obj, Elf_Size reloff, void *stack) 765 { 766 const Elf_Rel *rel; 767 const Elf_Sym *def; 768 const Obj_Entry *defobj; 769 Elf_Addr *where; 770 Elf_Addr target; 771 RtldLockState lockstate; 772 773 rlock_acquire(rtld_bind_lock, &lockstate); 774 if (sigsetjmp(lockstate.env, 0) != 0) 775 lock_upgrade(rtld_bind_lock, &lockstate); 776 if (obj->pltrel) 777 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 778 else 779 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 780 781 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 782 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL, 783 &lockstate); 784 if (def == NULL) 785 die(); 786 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 787 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 788 else 789 target = (Elf_Addr)(defobj->relocbase + def->st_value); 790 791 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 792 defobj->strtab + def->st_name, basename(obj->path), 793 (void *)target, basename(defobj->path)); 794 795 /* 796 * If we have a function call tracing hook, and the 797 * hook would like to keep tracing this one function, 798 * prevent the relocation so we will wind up here 799 * the next time again. 800 * 801 * We don't want to functrace calls from the functracer 802 * to avoid recursive loops. 803 */ 804 if (rtld_functrace != NULL && obj != rtld_functrace_obj) { 805 if (rtld_functrace(obj->path, 806 defobj->path, 807 defobj->strtab + def->st_name, 808 stack)) { 809 lock_release(rtld_bind_lock, &lockstate); 810 return target; 811 } 812 } 813 814 /* 815 * Write the new contents for the jmpslot. Note that depending on 816 * architecture, the value which we need to return back to the 817 * lazy binding trampoline may or may not be the target 818 * address. The value returned from reloc_jmpslot() is the value 819 * that the trampoline needs. 820 */ 821 target = reloc_jmpslot(where, target, defobj, obj, rel); 822 lock_release(rtld_bind_lock, &lockstate); 823 return target; 824 } 825 826 /* 827 * Error reporting function. Use it like printf. If formats the message 828 * into a buffer, and sets things up so that the next call to dlerror() 829 * will return the message. 830 */ 831 void 832 _rtld_error(const char *fmt, ...) 833 { 834 static char buf[512]; 835 va_list ap; 836 837 va_start(ap, fmt); 838 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 839 error_message = buf; 840 va_end(ap); 841 } 842 843 /* 844 * Return a dynamically-allocated copy of the current error message, if any. 845 */ 846 static char * 847 errmsg_save(void) 848 { 849 return error_message == NULL ? NULL : xstrdup(error_message); 850 } 851 852 /* 853 * Restore the current error message from a copy which was previously saved 854 * by errmsg_save(). The copy is freed. 855 */ 856 static void 857 errmsg_restore(char *saved_msg) 858 { 859 if (saved_msg == NULL) 860 error_message = NULL; 861 else { 862 _rtld_error("%s", saved_msg); 863 free(saved_msg); 864 } 865 } 866 867 const char * 868 basename(const char *name) 869 { 870 const char *p = strrchr(name, '/'); 871 return p != NULL ? p + 1 : name; 872 } 873 874 static struct utsname uts; 875 876 static int 877 origin_subst_one(char **res, const char *real, const char *kw, const char *subst, 878 char *may_free) 879 { 880 const char *p, *p1; 881 char *res1; 882 int subst_len; 883 int kw_len; 884 885 res1 = *res = NULL; 886 p = real; 887 subst_len = kw_len = 0; 888 for (;;) { 889 p1 = strstr(p, kw); 890 if (p1 != NULL) { 891 if (subst_len == 0) { 892 subst_len = strlen(subst); 893 kw_len = strlen(kw); 894 } 895 if (*res == NULL) { 896 *res = xmalloc(PATH_MAX); 897 res1 = *res; 898 } 899 if ((res1 - *res) + subst_len + (p1 - p) >= PATH_MAX) { 900 _rtld_error("Substitution of %s in %s cannot be performed", 901 kw, real); 902 if (may_free != NULL) 903 free(may_free); 904 free(res); 905 return (false); 906 } 907 memcpy(res1, p, p1 - p); 908 res1 += p1 - p; 909 memcpy(res1, subst, subst_len); 910 res1 += subst_len; 911 p = p1 + kw_len; 912 } else { 913 if (*res == NULL) { 914 if (may_free != NULL) 915 *res = may_free; 916 else 917 *res = xstrdup(real); 918 return (true); 919 } 920 *res1 = '\0'; 921 if (may_free != NULL) 922 free(may_free); 923 if (strlcat(res1, p, PATH_MAX - (res1 - *res)) >= PATH_MAX) { 924 free(res); 925 return (false); 926 } 927 return (true); 928 } 929 } 930 } 931 932 static char * 933 origin_subst(const char *real, const char *origin_path) 934 { 935 char *res1, *res2, *res3, *res4; 936 937 if (uts.sysname[0] == '\0') { 938 if (uname(&uts) != 0) { 939 _rtld_error("utsname failed: %d", errno); 940 return (NULL); 941 } 942 } 943 if (!origin_subst_one(&res1, real, "$ORIGIN", origin_path, NULL) || 944 !origin_subst_one(&res2, res1, "$OSNAME", uts.sysname, res1) || 945 !origin_subst_one(&res3, res2, "$OSREL", uts.release, res2) || 946 !origin_subst_one(&res4, res3, "$PLATFORM", uts.machine, res3)) 947 return (NULL); 948 return (res4); 949 } 950 951 static void 952 die(void) 953 { 954 const char *msg = dlerror(); 955 956 if (msg == NULL) 957 msg = "Fatal error"; 958 rtld_fdputstr(STDERR_FILENO, msg); 959 rtld_fdputchar(STDERR_FILENO, '\n'); 960 _exit(1); 961 } 962 963 /* 964 * Process a shared object's DYNAMIC section, and save the important 965 * information in its Obj_Entry structure. 966 */ 967 static void 968 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 969 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 970 { 971 const Elf_Dyn *dynp; 972 Needed_Entry **needed_tail = &obj->needed; 973 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 974 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 975 const Elf_Hashelt *hashtab; 976 const Elf32_Word *hashval; 977 Elf32_Word bkt, nmaskwords; 978 int bloom_size32; 979 bool nmw_power2; 980 int plttype = DT_REL; 981 982 *dyn_rpath = NULL; 983 *dyn_soname = NULL; 984 *dyn_runpath = NULL; 985 986 obj->bind_now = false; 987 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 988 switch (dynp->d_tag) { 989 990 case DT_REL: 991 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 992 break; 993 994 case DT_RELSZ: 995 obj->relsize = dynp->d_un.d_val; 996 break; 997 998 case DT_RELENT: 999 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 1000 break; 1001 1002 case DT_JMPREL: 1003 obj->pltrel = (const Elf_Rel *) 1004 (obj->relocbase + dynp->d_un.d_ptr); 1005 break; 1006 1007 case DT_PLTRELSZ: 1008 obj->pltrelsize = dynp->d_un.d_val; 1009 break; 1010 1011 case DT_RELA: 1012 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 1013 break; 1014 1015 case DT_RELASZ: 1016 obj->relasize = dynp->d_un.d_val; 1017 break; 1018 1019 case DT_RELAENT: 1020 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 1021 break; 1022 1023 case DT_PLTREL: 1024 plttype = dynp->d_un.d_val; 1025 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 1026 break; 1027 1028 case DT_SYMTAB: 1029 obj->symtab = (const Elf_Sym *) 1030 (obj->relocbase + dynp->d_un.d_ptr); 1031 break; 1032 1033 case DT_SYMENT: 1034 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 1035 break; 1036 1037 case DT_STRTAB: 1038 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 1039 break; 1040 1041 case DT_STRSZ: 1042 obj->strsize = dynp->d_un.d_val; 1043 break; 1044 1045 case DT_VERNEED: 1046 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 1047 dynp->d_un.d_val); 1048 break; 1049 1050 case DT_VERNEEDNUM: 1051 obj->verneednum = dynp->d_un.d_val; 1052 break; 1053 1054 case DT_VERDEF: 1055 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 1056 dynp->d_un.d_val); 1057 break; 1058 1059 case DT_VERDEFNUM: 1060 obj->verdefnum = dynp->d_un.d_val; 1061 break; 1062 1063 case DT_VERSYM: 1064 obj->versyms = (const Elf_Versym *)(obj->relocbase + 1065 dynp->d_un.d_val); 1066 break; 1067 1068 case DT_HASH: 1069 { 1070 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1071 dynp->d_un.d_ptr); 1072 obj->nbuckets = hashtab[0]; 1073 obj->nchains = hashtab[1]; 1074 obj->buckets = hashtab + 2; 1075 obj->chains = obj->buckets + obj->nbuckets; 1076 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 1077 obj->buckets != NULL; 1078 } 1079 break; 1080 1081 case DT_GNU_HASH: 1082 { 1083 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1084 dynp->d_un.d_ptr); 1085 obj->nbuckets_gnu = hashtab[0]; 1086 obj->symndx_gnu = hashtab[1]; 1087 nmaskwords = hashtab[2]; 1088 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1089 /* Number of bitmask words is required to be power of 2 */ 1090 nmw_power2 = ((nmaskwords & (nmaskwords - 1)) == 0); 1091 obj->maskwords_bm_gnu = nmaskwords - 1; 1092 obj->shift2_gnu = hashtab[3]; 1093 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4); 1094 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1095 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1096 obj->symndx_gnu; 1097 obj->valid_hash_gnu = nmw_power2 && obj->nbuckets_gnu > 0 && 1098 obj->buckets_gnu != NULL; 1099 } 1100 break; 1101 1102 case DT_NEEDED: 1103 if (!obj->rtld) { 1104 Needed_Entry *nep = NEW(Needed_Entry); 1105 nep->name = dynp->d_un.d_val; 1106 nep->obj = NULL; 1107 nep->next = NULL; 1108 1109 *needed_tail = nep; 1110 needed_tail = &nep->next; 1111 } 1112 break; 1113 1114 case DT_FILTER: 1115 if (!obj->rtld) { 1116 Needed_Entry *nep = NEW(Needed_Entry); 1117 nep->name = dynp->d_un.d_val; 1118 nep->obj = NULL; 1119 nep->next = NULL; 1120 1121 *needed_filtees_tail = nep; 1122 needed_filtees_tail = &nep->next; 1123 } 1124 break; 1125 1126 case DT_AUXILIARY: 1127 if (!obj->rtld) { 1128 Needed_Entry *nep = NEW(Needed_Entry); 1129 nep->name = dynp->d_un.d_val; 1130 nep->obj = NULL; 1131 nep->next = NULL; 1132 1133 *needed_aux_filtees_tail = nep; 1134 needed_aux_filtees_tail = &nep->next; 1135 } 1136 break; 1137 1138 case DT_PLTGOT: 1139 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 1140 break; 1141 1142 case DT_TEXTREL: 1143 obj->textrel = true; 1144 break; 1145 1146 case DT_SYMBOLIC: 1147 obj->symbolic = true; 1148 break; 1149 1150 case DT_RPATH: 1151 /* 1152 * We have to wait until later to process this, because we 1153 * might not have gotten the address of the string table yet. 1154 */ 1155 *dyn_rpath = dynp; 1156 break; 1157 1158 case DT_SONAME: 1159 *dyn_soname = dynp; 1160 break; 1161 1162 case DT_RUNPATH: 1163 *dyn_runpath = dynp; 1164 break; 1165 1166 case DT_INIT: 1167 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1168 break; 1169 1170 case DT_FINI: 1171 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1172 break; 1173 1174 case DT_PREINIT_ARRAY: 1175 obj->preinit_array = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1176 break; 1177 1178 case DT_INIT_ARRAY: 1179 obj->init_array = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1180 break; 1181 1182 case DT_FINI_ARRAY: 1183 obj->fini_array = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1184 break; 1185 1186 case DT_PREINIT_ARRAYSZ: 1187 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1188 break; 1189 1190 case DT_INIT_ARRAYSZ: 1191 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1192 break; 1193 1194 case DT_FINI_ARRAYSZ: 1195 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1196 break; 1197 1198 case DT_DEBUG: 1199 /* XXX - not implemented yet */ 1200 if (!early) 1201 dbg("Filling in DT_DEBUG entry"); 1202 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 1203 break; 1204 1205 case DT_FLAGS: 1206 if ((dynp->d_un.d_val & DF_ORIGIN) && trust) 1207 obj->z_origin = true; 1208 if (dynp->d_un.d_val & DF_SYMBOLIC) 1209 obj->symbolic = true; 1210 if (dynp->d_un.d_val & DF_TEXTREL) 1211 obj->textrel = true; 1212 if (dynp->d_un.d_val & DF_BIND_NOW) 1213 obj->bind_now = true; 1214 /*if (dynp->d_un.d_val & DF_STATIC_TLS) 1215 ;*/ 1216 break; 1217 1218 case DT_FLAGS_1: 1219 if (dynp->d_un.d_val & DF_1_NOOPEN) 1220 obj->z_noopen = true; 1221 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust) 1222 obj->z_origin = true; 1223 /*if (dynp->d_un.d_val & DF_1_GLOBAL) 1224 XXX ;*/ 1225 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1226 obj->bind_now = true; 1227 if (dynp->d_un.d_val & DF_1_NODELETE) 1228 obj->z_nodelete = true; 1229 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1230 obj->z_loadfltr = true; 1231 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1232 obj->z_nodeflib = true; 1233 break; 1234 1235 default: 1236 if (!early) { 1237 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1238 (long)dynp->d_tag); 1239 } 1240 break; 1241 } 1242 } 1243 1244 obj->traced = false; 1245 1246 if (plttype == DT_RELA) { 1247 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1248 obj->pltrel = NULL; 1249 obj->pltrelasize = obj->pltrelsize; 1250 obj->pltrelsize = 0; 1251 } 1252 1253 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1254 if (obj->valid_hash_sysv) 1255 obj->dynsymcount = obj->nchains; 1256 else if (obj->valid_hash_gnu) { 1257 obj->dynsymcount = 0; 1258 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1259 if (obj->buckets_gnu[bkt] == 0) 1260 continue; 1261 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1262 do 1263 obj->dynsymcount++; 1264 while ((*hashval++ & 1u) == 0); 1265 } 1266 obj->dynsymcount += obj->symndx_gnu; 1267 } 1268 } 1269 1270 static void 1271 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1272 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1273 { 1274 1275 if (obj->z_origin && obj->origin_path == NULL) { 1276 obj->origin_path = xmalloc(PATH_MAX); 1277 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1) 1278 die(); 1279 } 1280 1281 if (dyn_runpath != NULL) { 1282 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val; 1283 if (obj->z_origin) 1284 obj->runpath = origin_subst(obj->runpath, obj->origin_path); 1285 } 1286 else if (dyn_rpath != NULL) { 1287 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 1288 if (obj->z_origin) 1289 obj->rpath = origin_subst(obj->rpath, obj->origin_path); 1290 } 1291 1292 if (dyn_soname != NULL) 1293 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1294 } 1295 1296 static void 1297 digest_dynamic(Obj_Entry *obj, int early) 1298 { 1299 const Elf_Dyn *dyn_rpath; 1300 const Elf_Dyn *dyn_soname; 1301 const Elf_Dyn *dyn_runpath; 1302 1303 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1304 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath); 1305 } 1306 1307 /* 1308 * Process a shared object's program header. This is used only for the 1309 * main program, when the kernel has already loaded the main program 1310 * into memory before calling the dynamic linker. It creates and 1311 * returns an Obj_Entry structure. 1312 */ 1313 static Obj_Entry * 1314 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1315 { 1316 Obj_Entry *obj; 1317 const Elf_Phdr *phlimit = phdr + phnum; 1318 const Elf_Phdr *ph; 1319 Elf_Addr note_start, note_end; 1320 int nsegs = 0; 1321 1322 obj = obj_new(); 1323 for (ph = phdr; ph < phlimit; ph++) { 1324 if (ph->p_type != PT_PHDR) 1325 continue; 1326 1327 obj->phdr = phdr; 1328 obj->phsize = ph->p_memsz; 1329 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1330 break; 1331 } 1332 1333 obj->stack_flags = PF_X | PF_R | PF_W; 1334 1335 for (ph = phdr; ph < phlimit; ph++) { 1336 switch (ph->p_type) { 1337 1338 case PT_INTERP: 1339 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1340 break; 1341 1342 case PT_LOAD: 1343 if (nsegs == 0) { /* First load segment */ 1344 obj->vaddrbase = trunc_page(ph->p_vaddr); 1345 obj->mapbase = obj->vaddrbase + obj->relocbase; 1346 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1347 obj->vaddrbase; 1348 } else { /* Last load segment */ 1349 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1350 obj->vaddrbase; 1351 } 1352 nsegs++; 1353 break; 1354 1355 case PT_DYNAMIC: 1356 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1357 break; 1358 1359 case PT_TLS: 1360 obj->tlsindex = 1; 1361 obj->tlssize = ph->p_memsz; 1362 obj->tlsalign = ph->p_align; 1363 obj->tlsinitsize = ph->p_filesz; 1364 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1365 break; 1366 1367 case PT_GNU_STACK: 1368 obj->stack_flags = ph->p_flags; 1369 break; 1370 1371 case PT_GNU_RELRO: 1372 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1373 obj->relro_size = round_page(ph->p_memsz); 1374 break; 1375 1376 case PT_NOTE: 1377 obj->note_present = true; 1378 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1379 note_end = note_start + ph->p_filesz; 1380 digest_notes(obj, note_start, note_end); 1381 break; 1382 } 1383 } 1384 if (nsegs < 1) { 1385 _rtld_error("%s: too few PT_LOAD segments", path); 1386 return NULL; 1387 } 1388 1389 obj->entry = entry; 1390 return obj; 1391 } 1392 1393 void 1394 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1395 { 1396 const Elf_Note *note; 1397 const char *note_name; 1398 uintptr_t p; 1399 1400 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1401 note = (const Elf_Note *)((const char *)(note + 1) + 1402 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1403 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1404 if (note->n_namesz != sizeof(NOTE_VENDOR) || 1405 note->n_descsz != sizeof(int32_t)) 1406 continue; 1407 if (note->n_type != ABI_NOTETYPE && note->n_type != CRT_NOINIT_NOTETYPE) 1408 continue; 1409 note_name = (const char *)(note + 1); 1410 if (strncmp(NOTE_VENDOR, note_name, sizeof(NOTE_VENDOR)) != 0) 1411 continue; 1412 switch (note->n_type) { 1413 case ABI_NOTETYPE: 1414 /* DragonFly osrel note */ 1415 p = (uintptr_t)(note + 1); 1416 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1417 obj->osrel = *(const int32_t *)(p); 1418 dbg("note osrel %d", obj->osrel); 1419 break; 1420 case CRT_NOINIT_NOTETYPE: 1421 /* DragonFly 'crt does not call init' note */ 1422 obj->crt_no_init = true; 1423 dbg("note crt_no_init"); 1424 break; 1425 } 1426 } 1427 } 1428 1429 static Obj_Entry * 1430 dlcheck(void *handle) 1431 { 1432 Obj_Entry *obj; 1433 1434 for (obj = obj_list; obj != NULL; obj = obj->next) 1435 if (obj == (Obj_Entry *) handle) 1436 break; 1437 1438 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1439 _rtld_error("Invalid shared object handle %p", handle); 1440 return NULL; 1441 } 1442 return obj; 1443 } 1444 1445 /* 1446 * If the given object is already in the donelist, return true. Otherwise 1447 * add the object to the list and return false. 1448 */ 1449 static bool 1450 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1451 { 1452 unsigned int i; 1453 1454 for (i = 0; i < dlp->num_used; i++) 1455 if (dlp->objs[i] == obj) 1456 return true; 1457 /* 1458 * Our donelist allocation should always be sufficient. But if 1459 * our threads locking isn't working properly, more shared objects 1460 * could have been loaded since we allocated the list. That should 1461 * never happen, but we'll handle it properly just in case it does. 1462 */ 1463 if (dlp->num_used < dlp->num_alloc) 1464 dlp->objs[dlp->num_used++] = obj; 1465 return false; 1466 } 1467 1468 /* 1469 * Hash function for symbol table lookup. Don't even think about changing 1470 * this. It is specified by the System V ABI. 1471 */ 1472 unsigned long 1473 elf_hash(const char *name) 1474 { 1475 const unsigned char *p = (const unsigned char *) name; 1476 unsigned long h = 0; 1477 unsigned long g; 1478 1479 while (*p != '\0') { 1480 h = (h << 4) + *p++; 1481 if ((g = h & 0xf0000000) != 0) 1482 h ^= g >> 24; 1483 h &= ~g; 1484 } 1485 return h; 1486 } 1487 1488 /* 1489 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1490 * unsigned in case it's implemented with a wider type. 1491 */ 1492 static uint_fast32_t 1493 gnu_hash (const char *s) 1494 { 1495 uint_fast32_t h = 5381; 1496 for (unsigned char c = *s; c != '\0'; c = *++s) 1497 h = h * 33 + c; 1498 return h & 0xffffffff; 1499 } 1500 1501 /* 1502 * Find the library with the given name, and return its full pathname. 1503 * The returned string is dynamically allocated. Generates an error 1504 * message and returns NULL if the library cannot be found. 1505 * 1506 * If the second argument is non-NULL, then it refers to an already- 1507 * loaded shared object, whose library search path will be searched. 1508 * 1509 * The search order is: 1510 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1511 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1512 * LD_LIBRARY_PATH 1513 * DT_RUNPATH in the referencing file 1514 * ldconfig hints (if -z nodefaultlib, filter out /usr/lib from list) 1515 * /usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1516 * 1517 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1518 */ 1519 static char * 1520 find_library(const char *xname, const Obj_Entry *refobj) 1521 { 1522 char *pathname; 1523 char *name; 1524 bool objgiven = (refobj != NULL); 1525 1526 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */ 1527 if (xname[0] != '/' && !trust) { 1528 _rtld_error("Absolute pathname required for shared object \"%s\"", 1529 xname); 1530 return NULL; 1531 } 1532 if (objgiven && refobj->z_origin) 1533 return origin_subst(xname, refobj->origin_path); 1534 else 1535 return xstrdup(xname); 1536 } 1537 1538 if (libmap_disable || !objgiven || 1539 (name = lm_find(refobj->path, xname)) == NULL) 1540 name = (char *)xname; 1541 1542 dbg(" Searching for \"%s\"", name); 1543 1544 if ((objgiven && 1545 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1546 (objgiven && (refobj->runpath == NULL) && (refobj != obj_main) && 1547 (pathname = search_library_path(name, obj_main->rpath)) != NULL) || 1548 (pathname = search_library_path(name, ld_library_path)) != NULL || 1549 (objgiven && 1550 (pathname = search_library_path(name, refobj->runpath)) != NULL) || 1551 (pathname = search_library_path(name, gethints(refobj->z_nodeflib))) 1552 != NULL || 1553 (objgiven && !refobj->z_nodeflib && 1554 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)) 1555 return pathname; 1556 1557 if(objgiven && refobj->path != NULL) { 1558 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 1559 name, basename(refobj->path)); 1560 } else { 1561 _rtld_error("Shared object \"%s\" not found", name); 1562 } 1563 return NULL; 1564 } 1565 1566 /* 1567 * Given a symbol number in a referencing object, find the corresponding 1568 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1569 * no definition was found. Returns a pointer to the Obj_Entry of the 1570 * defining object via the reference parameter DEFOBJ_OUT. 1571 */ 1572 const Elf_Sym * 1573 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1574 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1575 RtldLockState *lockstate) 1576 { 1577 const Elf_Sym *ref; 1578 const Elf_Sym *def; 1579 const Obj_Entry *defobj; 1580 SymLook req; 1581 const char *name; 1582 int res; 1583 1584 /* 1585 * If we have already found this symbol, get the information from 1586 * the cache. 1587 */ 1588 if (symnum >= refobj->dynsymcount) 1589 return NULL; /* Bad object */ 1590 if (cache != NULL && cache[symnum].sym != NULL) { 1591 *defobj_out = cache[symnum].obj; 1592 return cache[symnum].sym; 1593 } 1594 1595 ref = refobj->symtab + symnum; 1596 name = refobj->strtab + ref->st_name; 1597 def = NULL; 1598 defobj = NULL; 1599 1600 /* 1601 * We don't have to do a full scale lookup if the symbol is local. 1602 * We know it will bind to the instance in this load module; to 1603 * which we already have a pointer (ie ref). By not doing a lookup, 1604 * we not only improve performance, but it also avoids unresolvable 1605 * symbols when local symbols are not in the hash table. 1606 * 1607 * This might occur for TLS module relocations, which simply use 1608 * symbol 0. 1609 */ 1610 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1611 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1612 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1613 symnum); 1614 } 1615 symlook_init(&req, name); 1616 req.flags = flags; 1617 req.ventry = fetch_ventry(refobj, symnum); 1618 req.lockstate = lockstate; 1619 res = symlook_default(&req, refobj); 1620 if (res == 0) { 1621 def = req.sym_out; 1622 defobj = req.defobj_out; 1623 } 1624 } else { 1625 def = ref; 1626 defobj = refobj; 1627 } 1628 1629 /* 1630 * If we found no definition and the reference is weak, treat the 1631 * symbol as having the value zero. 1632 */ 1633 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1634 def = &sym_zero; 1635 defobj = obj_main; 1636 } 1637 1638 if (def != NULL) { 1639 *defobj_out = defobj; 1640 /* Record the information in the cache to avoid subsequent lookups. */ 1641 if (cache != NULL) { 1642 cache[symnum].sym = def; 1643 cache[symnum].obj = defobj; 1644 } 1645 } else { 1646 if (refobj != &obj_rtld) 1647 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name); 1648 } 1649 return def; 1650 } 1651 1652 /* 1653 * Return the search path from the ldconfig hints file, reading it if 1654 * necessary. Returns NULL if there are problems with the hints file, 1655 * or if the search path there is empty. 1656 * If DF_1_NODEFLIB flag set, omit STANDARD_LIBRARY_PATH directories 1657 */ 1658 static const char * 1659 gethints(bool nostdlib) 1660 { 1661 static char *hints, *filtered_path; 1662 struct elfhints_hdr hdr; 1663 struct fill_search_info_args sargs, hargs; 1664 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1665 struct dl_serpath *SLPpath, *hintpath; 1666 char *p; 1667 unsigned int SLPndx, hintndx, fndx, fcount; 1668 int fd; 1669 size_t flen; 1670 bool skip; 1671 1672 if (hints == NULL) { 1673 /* Keep from trying again in case the hints file is bad. */ 1674 hints = ""; 1675 1676 if ((fd = open(ld_elf_hints_path, O_RDONLY)) == -1) 1677 return (NULL); 1678 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1679 hdr.magic != ELFHINTS_MAGIC || hdr.version != 1) { 1680 close(fd); 1681 return (NULL); 1682 } 1683 p = xmalloc(hdr.dirlistlen + 1); 1684 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1685 read(fd, p, hdr.dirlistlen + 1) != (ssize_t)hdr.dirlistlen + 1) { 1686 free(p); 1687 close(fd); 1688 return (NULL); 1689 } 1690 hints = p; 1691 close(fd); 1692 } 1693 1694 if (!nostdlib) 1695 return (hints[0] != '\0' ? hints : NULL); 1696 1697 if (filtered_path != NULL) 1698 goto filt_ret; 1699 1700 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1701 smeta.dls_cnt = 0; 1702 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1703 hmeta.dls_cnt = 0; 1704 1705 sargs.request = RTLD_DI_SERINFOSIZE; 1706 sargs.serinfo = &smeta; 1707 hargs.request = RTLD_DI_SERINFOSIZE; 1708 hargs.serinfo = &hmeta; 1709 1710 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1711 path_enumerate(p, fill_search_info, &hargs); 1712 1713 SLPinfo = malloc(smeta.dls_size); 1714 hintinfo = malloc(hmeta.dls_size); 1715 1716 sargs.request = RTLD_DI_SERINFO; 1717 sargs.serinfo = SLPinfo; 1718 sargs.serpath = &SLPinfo->dls_serpath[0]; 1719 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1720 1721 hargs.request = RTLD_DI_SERINFO; 1722 hargs.serinfo = hintinfo; 1723 hargs.serpath = &hintinfo->dls_serpath[0]; 1724 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1725 1726 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1727 path_enumerate(p, fill_search_info, &hargs); 1728 1729 fndx = 0; 1730 fcount = 0; 1731 filtered_path = xmalloc(hdr.dirlistlen + 1); 1732 hintpath = &hintinfo->dls_serpath[0]; 1733 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1734 skip = false; 1735 SLPpath = &SLPinfo->dls_serpath[0]; 1736 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1737 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1738 skip = true; 1739 break; 1740 } 1741 } 1742 if (skip) 1743 continue; 1744 if (fcount > 0) { 1745 filtered_path[fndx] = ':'; 1746 fndx++; 1747 } 1748 fcount++; 1749 flen = strlen(hintpath->dls_name); 1750 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1751 fndx+= flen; 1752 } 1753 filtered_path[fndx] = '\0'; 1754 1755 free(SLPinfo); 1756 free(hintinfo); 1757 1758 filt_ret: 1759 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1760 } 1761 1762 static void 1763 init_dag(Obj_Entry *root) 1764 { 1765 const Needed_Entry *needed; 1766 const Objlist_Entry *elm; 1767 DoneList donelist; 1768 1769 if (root->dag_inited) 1770 return; 1771 donelist_init(&donelist); 1772 1773 /* Root object belongs to own DAG. */ 1774 objlist_push_tail(&root->dldags, root); 1775 objlist_push_tail(&root->dagmembers, root); 1776 donelist_check(&donelist, root); 1777 1778 /* 1779 * Add dependencies of root object to DAG in breadth order 1780 * by exploiting the fact that each new object get added 1781 * to the tail of the dagmembers list. 1782 */ 1783 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1784 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1785 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1786 continue; 1787 objlist_push_tail(&needed->obj->dldags, root); 1788 objlist_push_tail(&root->dagmembers, needed->obj); 1789 } 1790 } 1791 root->dag_inited = true; 1792 } 1793 1794 static void 1795 process_nodelete(Obj_Entry *root) 1796 { 1797 const Objlist_Entry *elm; 1798 1799 /* 1800 * Walk over object DAG and process every dependent object that 1801 * is marked as DF_1_NODELETE. They need to grow their own DAG, 1802 * which then should have its reference upped separately. 1803 */ 1804 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1805 if (elm->obj != NULL && elm->obj->z_nodelete && 1806 !elm->obj->ref_nodel) { 1807 dbg("obj %s nodelete", elm->obj->path); 1808 init_dag(elm->obj); 1809 ref_dag(elm->obj); 1810 elm->obj->ref_nodel = true; 1811 } 1812 } 1813 } 1814 1815 /* 1816 * Initialize the dynamic linker. The argument is the address at which 1817 * the dynamic linker has been mapped into memory. The primary task of 1818 * this function is to relocate the dynamic linker. 1819 */ 1820 static void 1821 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 1822 { 1823 Obj_Entry objtmp; /* Temporary rtld object */ 1824 const Elf_Dyn *dyn_rpath; 1825 const Elf_Dyn *dyn_soname; 1826 const Elf_Dyn *dyn_runpath; 1827 1828 /* 1829 * Conjure up an Obj_Entry structure for the dynamic linker. 1830 * 1831 * The "path" member can't be initialized yet because string constants 1832 * cannot yet be accessed. Below we will set it correctly. 1833 */ 1834 memset(&objtmp, 0, sizeof(objtmp)); 1835 objtmp.path = NULL; 1836 objtmp.rtld = true; 1837 objtmp.mapbase = mapbase; 1838 #ifdef PIC 1839 objtmp.relocbase = mapbase; 1840 #endif 1841 if (RTLD_IS_DYNAMIC()) { 1842 objtmp.dynamic = rtld_dynamic(&objtmp); 1843 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 1844 assert(objtmp.needed == NULL); 1845 assert(!objtmp.textrel); 1846 1847 /* 1848 * Temporarily put the dynamic linker entry into the object list, so 1849 * that symbols can be found. 1850 */ 1851 1852 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 1853 } 1854 1855 /* Initialize the object list. */ 1856 obj_tail = &obj_list; 1857 1858 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1859 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1860 1861 #ifdef ENABLE_OSRELDATE 1862 if (aux_info[AT_OSRELDATE] != NULL) 1863 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 1864 #endif 1865 1866 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 1867 1868 /* Replace the path with a dynamically allocated copy. */ 1869 obj_rtld.path = xstrdup(PATH_RTLD); 1870 1871 r_debug.r_brk = r_debug_state; 1872 r_debug.r_state = RT_CONSISTENT; 1873 } 1874 1875 /* 1876 * Add the init functions from a needed object list (and its recursive 1877 * needed objects) to "list". This is not used directly; it is a helper 1878 * function for initlist_add_objects(). The write lock must be held 1879 * when this function is called. 1880 */ 1881 static void 1882 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 1883 { 1884 /* Recursively process the successor needed objects. */ 1885 if (needed->next != NULL) 1886 initlist_add_neededs(needed->next, list); 1887 1888 /* Process the current needed object. */ 1889 if (needed->obj != NULL) 1890 initlist_add_objects(needed->obj, &needed->obj->next, list); 1891 } 1892 1893 /* 1894 * Scan all of the DAGs rooted in the range of objects from "obj" to 1895 * "tail" and add their init functions to "list". This recurses over 1896 * the DAGs and ensure the proper init ordering such that each object's 1897 * needed libraries are initialized before the object itself. At the 1898 * same time, this function adds the objects to the global finalization 1899 * list "list_fini" in the opposite order. The write lock must be 1900 * held when this function is called. 1901 */ 1902 static void 1903 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list) 1904 { 1905 1906 if (obj->init_scanned || obj->init_done) 1907 return; 1908 obj->init_scanned = true; 1909 1910 /* Recursively process the successor objects. */ 1911 if (&obj->next != tail) 1912 initlist_add_objects(obj->next, tail, list); 1913 1914 /* Recursively process the needed objects. */ 1915 if (obj->needed != NULL) 1916 initlist_add_neededs(obj->needed, list); 1917 if (obj->needed_filtees != NULL) 1918 initlist_add_neededs(obj->needed_filtees, list); 1919 if (obj->needed_aux_filtees != NULL) 1920 initlist_add_neededs(obj->needed_aux_filtees, list); 1921 1922 /* Add the object to the init list. */ 1923 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL || 1924 obj->init_array != (Elf_Addr)NULL) 1925 objlist_push_tail(list, obj); 1926 1927 /* Add the object to the global fini list in the reverse order. */ 1928 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 1929 && !obj->on_fini_list) { 1930 objlist_push_head(&list_fini, obj); 1931 obj->on_fini_list = true; 1932 } 1933 } 1934 1935 #ifndef FPTR_TARGET 1936 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 1937 #endif 1938 1939 static bool 1940 is_exported(const Elf_Sym *def) 1941 { 1942 Elf_Addr value; 1943 const func_ptr_type *p; 1944 1945 value = (Elf_Addr)(obj_rtld.relocbase + def->st_value); 1946 for (p = exports; *p != NULL; p++) 1947 if (FPTR_TARGET(*p) == value) 1948 return true; 1949 return false; 1950 } 1951 1952 static void 1953 free_needed_filtees(Needed_Entry *n) 1954 { 1955 Needed_Entry *needed, *needed1; 1956 1957 for (needed = n; needed != NULL; needed = needed->next) { 1958 if (needed->obj != NULL) { 1959 dlclose(needed->obj); 1960 needed->obj = NULL; 1961 } 1962 } 1963 for (needed = n; needed != NULL; needed = needed1) { 1964 needed1 = needed->next; 1965 free(needed); 1966 } 1967 } 1968 1969 static void 1970 unload_filtees(Obj_Entry *obj) 1971 { 1972 1973 free_needed_filtees(obj->needed_filtees); 1974 obj->needed_filtees = NULL; 1975 free_needed_filtees(obj->needed_aux_filtees); 1976 obj->needed_aux_filtees = NULL; 1977 obj->filtees_loaded = false; 1978 } 1979 1980 static void 1981 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 1982 RtldLockState *lockstate) 1983 { 1984 1985 for (; needed != NULL; needed = needed->next) { 1986 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 1987 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 1988 RTLD_LOCAL, lockstate); 1989 } 1990 } 1991 1992 static void 1993 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 1994 { 1995 1996 lock_restart_for_upgrade(lockstate); 1997 if (!obj->filtees_loaded) { 1998 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 1999 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2000 obj->filtees_loaded = true; 2001 } 2002 } 2003 2004 static int 2005 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2006 { 2007 Obj_Entry *obj1; 2008 2009 for (; needed != NULL; needed = needed->next) { 2010 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2011 flags & ~RTLD_LO_NOLOAD); 2012 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2013 return (-1); 2014 } 2015 return (0); 2016 } 2017 2018 /* 2019 * Given a shared object, traverse its list of needed objects, and load 2020 * each of them. Returns 0 on success. Generates an error message and 2021 * returns -1 on failure. 2022 */ 2023 static int 2024 load_needed_objects(Obj_Entry *first, int flags) 2025 { 2026 Obj_Entry *obj; 2027 2028 for (obj = first; obj != NULL; obj = obj->next) { 2029 if (process_needed(obj, obj->needed, flags) == -1) 2030 return (-1); 2031 } 2032 return (0); 2033 } 2034 2035 static int 2036 load_preload_objects(void) 2037 { 2038 char *p = ld_preload; 2039 static const char delim[] = " \t:;"; 2040 2041 if (p == NULL) 2042 return 0; 2043 2044 p += strspn(p, delim); 2045 while (*p != '\0') { 2046 size_t len = strcspn(p, delim); 2047 char savech; 2048 Obj_Entry *obj; 2049 SymLook req; 2050 int res; 2051 2052 savech = p[len]; 2053 p[len] = '\0'; 2054 obj = load_object(p, -1, NULL, 0); 2055 if (obj == NULL) 2056 return -1; /* XXX - cleanup */ 2057 p[len] = savech; 2058 p += len; 2059 p += strspn(p, delim); 2060 2061 /* Check for the magic tracing function */ 2062 symlook_init(&req, RTLD_FUNCTRACE); 2063 res = symlook_obj(&req, obj); 2064 if (res == 0) { 2065 rtld_functrace = (void *)(req.defobj_out->relocbase + 2066 req.sym_out->st_value); 2067 rtld_functrace_obj = req.defobj_out; 2068 } 2069 } 2070 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2071 return 0; 2072 } 2073 2074 static const char * 2075 printable_path(const char *path) 2076 { 2077 2078 return (path == NULL ? "<unknown>" : path); 2079 } 2080 2081 /* 2082 * Load a shared object into memory, if it is not already loaded. The 2083 * object may be specified by name or by user-supplied file descriptor 2084 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2085 * duplicate is. 2086 * 2087 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2088 * on failure. 2089 */ 2090 static Obj_Entry * 2091 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2092 { 2093 Obj_Entry *obj; 2094 int fd; 2095 struct stat sb; 2096 char *path; 2097 2098 if (name != NULL) { 2099 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 2100 if (object_match_name(obj, name)) 2101 return (obj); 2102 } 2103 2104 path = find_library(name, refobj); 2105 if (path == NULL) 2106 return (NULL); 2107 } else 2108 path = NULL; 2109 2110 /* 2111 * If we didn't find a match by pathname, or the name is not 2112 * supplied, open the file and check again by device and inode. 2113 * This avoids false mismatches caused by multiple links or ".." 2114 * in pathnames. 2115 * 2116 * To avoid a race, we open the file and use fstat() rather than 2117 * using stat(). 2118 */ 2119 fd = -1; 2120 if (fd_u == -1) { 2121 if ((fd = open(path, O_RDONLY)) == -1) { 2122 _rtld_error("Cannot open \"%s\"", path); 2123 free(path); 2124 return (NULL); 2125 } 2126 } else { 2127 fd = dup(fd_u); 2128 if (fd == -1) { 2129 _rtld_error("Cannot dup fd"); 2130 free(path); 2131 return (NULL); 2132 } 2133 } 2134 if (fstat(fd, &sb) == -1) { 2135 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2136 close(fd); 2137 free(path); 2138 return NULL; 2139 } 2140 for (obj = obj_list->next; obj != NULL; obj = obj->next) 2141 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2142 break; 2143 if (obj != NULL && name != NULL) { 2144 object_add_name(obj, name); 2145 free(path); 2146 close(fd); 2147 return obj; 2148 } 2149 if (flags & RTLD_LO_NOLOAD) { 2150 free(path); 2151 close(fd); 2152 return (NULL); 2153 } 2154 2155 /* First use of this object, so we must map it in */ 2156 obj = do_load_object(fd, name, path, &sb, flags); 2157 if (obj == NULL) 2158 free(path); 2159 close(fd); 2160 2161 return obj; 2162 } 2163 2164 static Obj_Entry * 2165 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2166 int flags) 2167 { 2168 Obj_Entry *obj; 2169 struct statfs fs; 2170 2171 /* 2172 * but first, make sure that environment variables haven't been 2173 * used to circumvent the noexec flag on a filesystem. 2174 */ 2175 if (dangerous_ld_env) { 2176 if (fstatfs(fd, &fs) != 0) { 2177 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2178 return NULL; 2179 } 2180 if (fs.f_flags & MNT_NOEXEC) { 2181 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 2182 return NULL; 2183 } 2184 } 2185 dbg("loading \"%s\"", printable_path(path)); 2186 obj = map_object(fd, printable_path(path), sbp); 2187 if (obj == NULL) 2188 return NULL; 2189 2190 /* 2191 * If DT_SONAME is present in the object, digest_dynamic2 already 2192 * added it to the object names. 2193 */ 2194 if (name != NULL) 2195 object_add_name(obj, name); 2196 obj->path = path; 2197 digest_dynamic(obj, 0); 2198 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2199 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2200 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2201 RTLD_LO_DLOPEN) { 2202 dbg("refusing to load non-loadable \"%s\"", obj->path); 2203 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2204 munmap(obj->mapbase, obj->mapsize); 2205 obj_free(obj); 2206 return (NULL); 2207 } 2208 2209 *obj_tail = obj; 2210 obj_tail = &obj->next; 2211 obj_count++; 2212 obj_loads++; 2213 linkmap_add(obj); /* for GDB & dlinfo() */ 2214 max_stack_flags |= obj->stack_flags; 2215 2216 dbg(" %p .. %p: %s", obj->mapbase, 2217 obj->mapbase + obj->mapsize - 1, obj->path); 2218 if (obj->textrel) 2219 dbg(" WARNING: %s has impure text", obj->path); 2220 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2221 obj->path); 2222 2223 return obj; 2224 } 2225 2226 static Obj_Entry * 2227 obj_from_addr(const void *addr) 2228 { 2229 Obj_Entry *obj; 2230 2231 for (obj = obj_list; obj != NULL; obj = obj->next) { 2232 if (addr < (void *) obj->mapbase) 2233 continue; 2234 if (addr < (void *) (obj->mapbase + obj->mapsize)) 2235 return obj; 2236 } 2237 return NULL; 2238 } 2239 2240 /* 2241 * Call the finalization functions for each of the objects in "list" 2242 * belonging to the DAG of "root" and referenced once. If NULL "root" 2243 * is specified, every finalization function will be called regardless 2244 * of the reference count and the list elements won't be freed. All of 2245 * the objects are expected to have non-NULL fini functions. 2246 */ 2247 static void 2248 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2249 { 2250 Objlist_Entry *elm; 2251 char *saved_msg; 2252 Elf_Addr *fini_addr; 2253 int index; 2254 2255 assert(root == NULL || root->refcount == 1); 2256 2257 /* 2258 * Preserve the current error message since a fini function might 2259 * call into the dynamic linker and overwrite it. 2260 */ 2261 saved_msg = errmsg_save(); 2262 do { 2263 STAILQ_FOREACH(elm, list, link) { 2264 if (root != NULL && (elm->obj->refcount != 1 || 2265 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2266 continue; 2267 2268 /* Remove object from fini list to prevent recursive invocation. */ 2269 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2270 /* 2271 * XXX: If a dlopen() call references an object while the 2272 * fini function is in progress, we might end up trying to 2273 * unload the referenced object in dlclose() or the object 2274 * won't be unloaded although its fini function has been 2275 * called. 2276 */ 2277 lock_release(rtld_bind_lock, lockstate); 2278 2279 /* 2280 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. When this 2281 * happens, DT_FINI_ARRAY is processed first, and it is also processed 2282 * backwards. It is possible to encounter DT_FINI_ARRAY elements with 2283 * values of 0 or 1, but they need to be ignored. 2284 */ 2285 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2286 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2287 for (index = elm->obj->fini_array_num - 1; index >= 0; index--) { 2288 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2289 dbg("calling fini array function for %s at %p", 2290 elm->obj->path, (void *)fini_addr[index]); 2291 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2292 (void *)fini_addr[index], 0, 0, elm->obj->path); 2293 call_initfini_pointer(elm->obj, fini_addr[index]); 2294 } 2295 } 2296 } 2297 if (elm->obj->fini != (Elf_Addr)NULL) { 2298 dbg("calling fini function for %s at %p", elm->obj->path, 2299 (void *)elm->obj->fini); 2300 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2301 0, 0, elm->obj->path); 2302 call_initfini_pointer(elm->obj, elm->obj->fini); 2303 } 2304 wlock_acquire(rtld_bind_lock, lockstate); 2305 /* No need to free anything if process is going down. */ 2306 if (root != NULL) 2307 free(elm); 2308 /* 2309 * We must restart the list traversal after every fini call 2310 * because a dlclose() call from the fini function or from 2311 * another thread might have modified the reference counts. 2312 */ 2313 break; 2314 } 2315 } while (elm != NULL); 2316 errmsg_restore(saved_msg); 2317 } 2318 2319 /* 2320 * If the main program is defined with a .preinit_array section, call 2321 * each function in order. This must occur before the initialization 2322 * of any shared object or the main program. 2323 */ 2324 static void 2325 preinitialize_main_object (void) 2326 { 2327 Elf_Addr *preinit_addr; 2328 int index; 2329 2330 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2331 if (preinit_addr == NULL) 2332 return; 2333 2334 for (index = 0; index < obj_main->preinit_array_num; index++) { 2335 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2336 dbg("calling preinit function for %s at %p", obj_main->path, 2337 (void *)preinit_addr[index]); 2338 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2339 0, 0, obj_main->path); 2340 call_init_pointer(obj_main, preinit_addr[index]); 2341 } 2342 } 2343 } 2344 2345 /* 2346 * Call the initialization functions for each of the objects in 2347 * "list". All of the objects are expected to have non-NULL init 2348 * functions. 2349 */ 2350 static void 2351 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2352 { 2353 Objlist_Entry *elm; 2354 Obj_Entry *obj; 2355 char *saved_msg; 2356 Elf_Addr *init_addr; 2357 int index; 2358 2359 /* 2360 * Clean init_scanned flag so that objects can be rechecked and 2361 * possibly initialized earlier if any of vectors called below 2362 * cause the change by using dlopen. 2363 */ 2364 for (obj = obj_list; obj != NULL; obj = obj->next) 2365 obj->init_scanned = false; 2366 2367 /* 2368 * Preserve the current error message since an init function might 2369 * call into the dynamic linker and overwrite it. 2370 */ 2371 saved_msg = errmsg_save(); 2372 STAILQ_FOREACH(elm, list, link) { 2373 if (elm->obj->init_done) /* Initialized early. */ 2374 continue; 2375 2376 /* 2377 * Race: other thread might try to use this object before current 2378 * one completes the initilization. Not much can be done here 2379 * without better locking. 2380 */ 2381 elm->obj->init_done = true; 2382 lock_release(rtld_bind_lock, lockstate); 2383 2384 /* 2385 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. When 2386 * this happens, DT_INIT is processed first. It is possible to 2387 * encounter DT_INIT_ARRAY elements with values of 0 or 1, but they 2388 * need to be ignored. 2389 */ 2390 if (elm->obj->init != (Elf_Addr)NULL) { 2391 dbg("calling init function for %s at %p", elm->obj->path, 2392 (void *)elm->obj->init); 2393 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2394 0, 0, elm->obj->path); 2395 call_initfini_pointer(elm->obj, elm->obj->init); 2396 } 2397 init_addr = (Elf_Addr *)elm->obj->init_array; 2398 if (init_addr != NULL) { 2399 for (index = 0; index < elm->obj->init_array_num; index++) { 2400 if (init_addr[index] != 0 && init_addr[index] != 1) { 2401 dbg("calling init array function for %s at %p", elm->obj->path, 2402 (void *)init_addr[index]); 2403 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2404 (void *)init_addr[index], 0, 0, elm->obj->path); 2405 call_init_pointer(elm->obj, init_addr[index]); 2406 } 2407 } 2408 } 2409 wlock_acquire(rtld_bind_lock, lockstate); 2410 } 2411 errmsg_restore(saved_msg); 2412 } 2413 2414 static void 2415 objlist_clear(Objlist *list) 2416 { 2417 Objlist_Entry *elm; 2418 2419 while (!STAILQ_EMPTY(list)) { 2420 elm = STAILQ_FIRST(list); 2421 STAILQ_REMOVE_HEAD(list, link); 2422 free(elm); 2423 } 2424 } 2425 2426 static Objlist_Entry * 2427 objlist_find(Objlist *list, const Obj_Entry *obj) 2428 { 2429 Objlist_Entry *elm; 2430 2431 STAILQ_FOREACH(elm, list, link) 2432 if (elm->obj == obj) 2433 return elm; 2434 return NULL; 2435 } 2436 2437 static void 2438 objlist_init(Objlist *list) 2439 { 2440 STAILQ_INIT(list); 2441 } 2442 2443 static void 2444 objlist_push_head(Objlist *list, Obj_Entry *obj) 2445 { 2446 Objlist_Entry *elm; 2447 2448 elm = NEW(Objlist_Entry); 2449 elm->obj = obj; 2450 STAILQ_INSERT_HEAD(list, elm, link); 2451 } 2452 2453 static void 2454 objlist_push_tail(Objlist *list, Obj_Entry *obj) 2455 { 2456 Objlist_Entry *elm; 2457 2458 elm = NEW(Objlist_Entry); 2459 elm->obj = obj; 2460 STAILQ_INSERT_TAIL(list, elm, link); 2461 } 2462 2463 static void 2464 objlist_remove(Objlist *list, Obj_Entry *obj) 2465 { 2466 Objlist_Entry *elm; 2467 2468 if ((elm = objlist_find(list, obj)) != NULL) { 2469 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2470 free(elm); 2471 } 2472 } 2473 2474 /* 2475 * Relocate dag rooted in the specified object. 2476 * Returns 0 on success, or -1 on failure. 2477 */ 2478 2479 static int 2480 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2481 int flags, RtldLockState *lockstate) 2482 { 2483 Objlist_Entry *elm; 2484 int error; 2485 2486 error = 0; 2487 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2488 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2489 lockstate); 2490 if (error == -1) 2491 break; 2492 } 2493 return (error); 2494 } 2495 2496 /* 2497 * Relocate single object. 2498 * Returns 0 on success, or -1 on failure. 2499 */ 2500 2501 static int 2502 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2503 int flags, RtldLockState *lockstate) 2504 { 2505 if (obj->relocated) 2506 return (0); 2507 obj->relocated = true; 2508 if (obj != rtldobj) 2509 dbg("relocating \"%s\"", obj->path); 2510 2511 if (obj->symtab == NULL || obj->strtab == NULL || 2512 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2513 _rtld_error("%s: Shared object has no run-time symbol table", 2514 obj->path); 2515 return (-1); 2516 } 2517 2518 if (obj->textrel) { 2519 /* There are relocations to the write-protected text segment. */ 2520 if (mprotect(obj->mapbase, obj->textsize, 2521 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) { 2522 _rtld_error("%s: Cannot write-enable text segment: %s", 2523 obj->path, rtld_strerror(errno)); 2524 return (-1); 2525 } 2526 } 2527 2528 /* Process the non-PLT relocations. */ 2529 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2530 return (-1); 2531 2532 /* 2533 * Reprotect the text segment. Make sure it is included in the 2534 * core dump since we modified it. This unfortunately causes the 2535 * entire text segment to core-out but we don't have much of a 2536 * choice. We could try to only reenable core dumps on pages 2537 * in which relocations occured but that is likely most of the text 2538 * pages anyway, and even that would not work because the rest of 2539 * the text pages would wind up as a read-only OBJT_DEFAULT object 2540 * (created due to our modifications) backed by the original OBJT_VNODE 2541 * object, and the ELF coredump code is currently only able to dump 2542 * vnode records for pure vnode-backed mappings, not vnode backings 2543 * to memory objects. 2544 */ 2545 if (obj->textrel) { 2546 madvise(obj->mapbase, obj->textsize, MADV_CORE); 2547 if (mprotect(obj->mapbase, obj->textsize, 2548 PROT_READ|PROT_EXEC) == -1) { 2549 _rtld_error("%s: Cannot write-protect text segment: %s", 2550 obj->path, rtld_strerror(errno)); 2551 return (-1); 2552 } 2553 } 2554 2555 2556 /* Set the special PLT or GOT entries. */ 2557 init_pltgot(obj); 2558 2559 /* Process the PLT relocations. */ 2560 if (reloc_plt(obj) == -1) 2561 return (-1); 2562 /* Relocate the jump slots if we are doing immediate binding. */ 2563 if (obj->bind_now || bind_now) 2564 if (reloc_jmpslots(obj, flags, lockstate) == -1) 2565 return (-1); 2566 2567 /* 2568 * Set up the magic number and version in the Obj_Entry. These 2569 * were checked in the crt1.o from the original ElfKit, so we 2570 * set them for backward compatibility. 2571 */ 2572 obj->magic = RTLD_MAGIC; 2573 obj->version = RTLD_VERSION; 2574 2575 /* 2576 * Set relocated data to read-only status if protection specified 2577 */ 2578 2579 if (obj->relro_size) { 2580 if (mprotect(obj->relro_page, obj->relro_size, PROT_READ) == -1) { 2581 _rtld_error("%s: Cannot enforce relro relocation: %s", 2582 obj->path, rtld_strerror(errno)); 2583 return (-1); 2584 } 2585 } 2586 return (0); 2587 } 2588 2589 /* 2590 * Relocate newly-loaded shared objects. The argument is a pointer to 2591 * the Obj_Entry for the first such object. All objects from the first 2592 * to the end of the list of objects are relocated. Returns 0 on success, 2593 * or -1 on failure. 2594 */ 2595 static int 2596 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2597 int flags, RtldLockState *lockstate) 2598 { 2599 Obj_Entry *obj; 2600 int error; 2601 2602 for (error = 0, obj = first; obj != NULL; obj = obj->next) { 2603 error = relocate_object(obj, bind_now, rtldobj, flags, 2604 lockstate); 2605 if (error == -1) 2606 break; 2607 } 2608 return (error); 2609 } 2610 2611 /* 2612 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2613 * referencing STT_GNU_IFUNC symbols is postponed till the other 2614 * relocations are done. The indirect functions specified as 2615 * ifunc are allowed to call other symbols, so we need to have 2616 * objects relocated before asking for resolution from indirects. 2617 * 2618 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2619 * instead of the usual lazy handling of PLT slots. It is 2620 * consistent with how GNU does it. 2621 */ 2622 static int 2623 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2624 RtldLockState *lockstate) 2625 { 2626 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2627 return (-1); 2628 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2629 reloc_gnu_ifunc(obj, flags, lockstate) == -1) 2630 return (-1); 2631 return (0); 2632 } 2633 2634 static int 2635 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags, 2636 RtldLockState *lockstate) 2637 { 2638 Obj_Entry *obj; 2639 2640 for (obj = first; obj != NULL; obj = obj->next) { 2641 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1) 2642 return (-1); 2643 } 2644 return (0); 2645 } 2646 2647 static int 2648 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2649 RtldLockState *lockstate) 2650 { 2651 Objlist_Entry *elm; 2652 2653 STAILQ_FOREACH(elm, list, link) { 2654 if (resolve_object_ifunc(elm->obj, bind_now, flags, 2655 lockstate) == -1) 2656 return (-1); 2657 } 2658 return (0); 2659 } 2660 2661 /* 2662 * Cleanup procedure. It will be called (by the atexit mechanism) just 2663 * before the process exits. 2664 */ 2665 static void 2666 rtld_exit(void) 2667 { 2668 RtldLockState lockstate; 2669 2670 wlock_acquire(rtld_bind_lock, &lockstate); 2671 dbg("rtld_exit()"); 2672 objlist_call_fini(&list_fini, NULL, &lockstate); 2673 /* No need to remove the items from the list, since we are exiting. */ 2674 if (!libmap_disable) 2675 lm_fini(); 2676 lock_release(rtld_bind_lock, &lockstate); 2677 } 2678 2679 static void * 2680 path_enumerate(const char *path, path_enum_proc callback, void *arg) 2681 { 2682 if (path == NULL) 2683 return (NULL); 2684 2685 path += strspn(path, ":;"); 2686 while (*path != '\0') { 2687 size_t len; 2688 char *res; 2689 2690 len = strcspn(path, ":;"); 2691 res = callback(path, len, arg); 2692 2693 if (res != NULL) 2694 return (res); 2695 2696 path += len; 2697 path += strspn(path, ":;"); 2698 } 2699 2700 return (NULL); 2701 } 2702 2703 struct try_library_args { 2704 const char *name; 2705 size_t namelen; 2706 char *buffer; 2707 size_t buflen; 2708 }; 2709 2710 static void * 2711 try_library_path(const char *dir, size_t dirlen, void *param) 2712 { 2713 struct try_library_args *arg; 2714 2715 arg = param; 2716 if (*dir == '/' || trust) { 2717 char *pathname; 2718 2719 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 2720 return (NULL); 2721 2722 pathname = arg->buffer; 2723 strncpy(pathname, dir, dirlen); 2724 pathname[dirlen] = '/'; 2725 strcpy(pathname + dirlen + 1, arg->name); 2726 2727 dbg(" Trying \"%s\"", pathname); 2728 if (access(pathname, F_OK) == 0) { /* We found it */ 2729 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 2730 strcpy(pathname, arg->buffer); 2731 return (pathname); 2732 } 2733 } 2734 return (NULL); 2735 } 2736 2737 static char * 2738 search_library_path(const char *name, const char *path) 2739 { 2740 char *p; 2741 struct try_library_args arg; 2742 2743 if (path == NULL) 2744 return NULL; 2745 2746 arg.name = name; 2747 arg.namelen = strlen(name); 2748 arg.buffer = xmalloc(PATH_MAX); 2749 arg.buflen = PATH_MAX; 2750 2751 p = path_enumerate(path, try_library_path, &arg); 2752 2753 free(arg.buffer); 2754 2755 return (p); 2756 } 2757 2758 int 2759 dlclose(void *handle) 2760 { 2761 Obj_Entry *root; 2762 RtldLockState lockstate; 2763 2764 wlock_acquire(rtld_bind_lock, &lockstate); 2765 root = dlcheck(handle); 2766 if (root == NULL) { 2767 lock_release(rtld_bind_lock, &lockstate); 2768 return -1; 2769 } 2770 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 2771 root->path); 2772 2773 /* Unreference the object and its dependencies. */ 2774 root->dl_refcount--; 2775 2776 if (root->refcount == 1) { 2777 /* 2778 * The object will be no longer referenced, so we must unload it. 2779 * First, call the fini functions. 2780 */ 2781 objlist_call_fini(&list_fini, root, &lockstate); 2782 2783 unref_dag(root); 2784 2785 /* Finish cleaning up the newly-unreferenced objects. */ 2786 GDB_STATE(RT_DELETE,&root->linkmap); 2787 unload_object(root); 2788 GDB_STATE(RT_CONSISTENT,NULL); 2789 } else 2790 unref_dag(root); 2791 2792 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 2793 lock_release(rtld_bind_lock, &lockstate); 2794 return 0; 2795 } 2796 2797 char * 2798 dlerror(void) 2799 { 2800 char *msg = error_message; 2801 error_message = NULL; 2802 return msg; 2803 } 2804 2805 void * 2806 dlopen(const char *name, int mode) 2807 { 2808 2809 return (rtld_dlopen(name, -1, mode)); 2810 } 2811 2812 void * 2813 fdlopen(int fd, int mode) 2814 { 2815 2816 return (rtld_dlopen(NULL, fd, mode)); 2817 } 2818 2819 static void * 2820 rtld_dlopen(const char *name, int fd, int mode) 2821 { 2822 RtldLockState lockstate; 2823 int lo_flags; 2824 2825 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 2826 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 2827 if (ld_tracing != NULL) { 2828 rlock_acquire(rtld_bind_lock, &lockstate); 2829 if (sigsetjmp(lockstate.env, 0) != 0) 2830 lock_upgrade(rtld_bind_lock, &lockstate); 2831 environ = (char **)*get_program_var_addr("environ", &lockstate); 2832 lock_release(rtld_bind_lock, &lockstate); 2833 } 2834 lo_flags = RTLD_LO_DLOPEN; 2835 if (mode & RTLD_NODELETE) 2836 lo_flags |= RTLD_LO_NODELETE; 2837 if (mode & RTLD_NOLOAD) 2838 lo_flags |= RTLD_LO_NOLOAD; 2839 if (ld_tracing != NULL) 2840 lo_flags |= RTLD_LO_TRACE; 2841 2842 return (dlopen_object(name, fd, obj_main, lo_flags, 2843 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 2844 } 2845 2846 static void 2847 dlopen_cleanup(Obj_Entry *obj) 2848 { 2849 2850 obj->dl_refcount--; 2851 unref_dag(obj); 2852 if (obj->refcount == 0) 2853 unload_object(obj); 2854 } 2855 2856 static Obj_Entry * 2857 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 2858 int mode, RtldLockState *lockstate) 2859 { 2860 Obj_Entry **old_obj_tail; 2861 Obj_Entry *obj; 2862 Objlist initlist; 2863 RtldLockState mlockstate; 2864 int result; 2865 2866 objlist_init(&initlist); 2867 2868 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 2869 wlock_acquire(rtld_bind_lock, &mlockstate); 2870 lockstate = &mlockstate; 2871 } 2872 GDB_STATE(RT_ADD,NULL); 2873 2874 old_obj_tail = obj_tail; 2875 obj = NULL; 2876 if (name == NULL && fd == -1) { 2877 obj = obj_main; 2878 obj->refcount++; 2879 } else { 2880 obj = load_object(name, fd, refobj, lo_flags); 2881 } 2882 2883 if (obj) { 2884 obj->dl_refcount++; 2885 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 2886 objlist_push_tail(&list_global, obj); 2887 if (*old_obj_tail != NULL) { /* We loaded something new. */ 2888 assert(*old_obj_tail == obj); 2889 result = load_needed_objects(obj, 2890 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 2891 init_dag(obj); 2892 ref_dag(obj); 2893 if (result != -1) 2894 result = rtld_verify_versions(&obj->dagmembers); 2895 if (result != -1 && ld_tracing) 2896 goto trace; 2897 if (result == -1 || relocate_object_dag(obj, 2898 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 2899 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 2900 lockstate) == -1) { 2901 dlopen_cleanup(obj); 2902 obj = NULL; 2903 } else if (lo_flags & RTLD_LO_EARLY) { 2904 /* 2905 * Do not call the init functions for early loaded 2906 * filtees. The image is still not initialized enough 2907 * for them to work. 2908 * 2909 * Our object is found by the global object list and 2910 * will be ordered among all init calls done right 2911 * before transferring control to main. 2912 */ 2913 } else { 2914 /* Make list of init functions to call. */ 2915 initlist_add_objects(obj, &obj->next, &initlist); 2916 } 2917 /* 2918 * Process all no_delete objects here, given them own 2919 * DAGs to prevent their dependencies from being unloaded. 2920 * This has to be done after we have loaded all of the 2921 * dependencies, so that we do not miss any. 2922 */ 2923 if (obj != NULL) 2924 process_nodelete(obj); 2925 } else { 2926 /* 2927 * Bump the reference counts for objects on this DAG. If 2928 * this is the first dlopen() call for the object that was 2929 * already loaded as a dependency, initialize the dag 2930 * starting at it. 2931 */ 2932 init_dag(obj); 2933 ref_dag(obj); 2934 2935 if ((lo_flags & RTLD_LO_TRACE) != 0) 2936 goto trace; 2937 } 2938 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 2939 obj->z_nodelete) && !obj->ref_nodel) { 2940 dbg("obj %s nodelete", obj->path); 2941 ref_dag(obj); 2942 obj->z_nodelete = obj->ref_nodel = true; 2943 } 2944 } 2945 2946 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 2947 name); 2948 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 2949 2950 if (!(lo_flags & RTLD_LO_EARLY)) { 2951 map_stacks_exec(lockstate); 2952 } 2953 2954 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 2955 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 2956 lockstate) == -1) { 2957 objlist_clear(&initlist); 2958 dlopen_cleanup(obj); 2959 if (lockstate == &mlockstate) 2960 lock_release(rtld_bind_lock, lockstate); 2961 return (NULL); 2962 } 2963 2964 if (!(lo_flags & RTLD_LO_EARLY)) { 2965 /* Call the init functions. */ 2966 objlist_call_init(&initlist, lockstate); 2967 } 2968 objlist_clear(&initlist); 2969 if (lockstate == &mlockstate) 2970 lock_release(rtld_bind_lock, lockstate); 2971 return obj; 2972 trace: 2973 trace_loaded_objects(obj); 2974 if (lockstate == &mlockstate) 2975 lock_release(rtld_bind_lock, lockstate); 2976 exit(0); 2977 } 2978 2979 static void * 2980 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 2981 int flags) 2982 { 2983 DoneList donelist; 2984 const Obj_Entry *obj, *defobj; 2985 const Elf_Sym *def; 2986 SymLook req; 2987 RtldLockState lockstate; 2988 int res; 2989 2990 def = NULL; 2991 defobj = NULL; 2992 symlook_init(&req, name); 2993 req.ventry = ve; 2994 req.flags = flags | SYMLOOK_IN_PLT; 2995 req.lockstate = &lockstate; 2996 2997 rlock_acquire(rtld_bind_lock, &lockstate); 2998 if (sigsetjmp(lockstate.env, 0) != 0) 2999 lock_upgrade(rtld_bind_lock, &lockstate); 3000 if (handle == NULL || handle == RTLD_NEXT || 3001 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3002 3003 if ((obj = obj_from_addr(retaddr)) == NULL) { 3004 _rtld_error("Cannot determine caller's shared object"); 3005 lock_release(rtld_bind_lock, &lockstate); 3006 return NULL; 3007 } 3008 if (handle == NULL) { /* Just the caller's shared object. */ 3009 res = symlook_obj(&req, obj); 3010 if (res == 0) { 3011 def = req.sym_out; 3012 defobj = req.defobj_out; 3013 } 3014 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3015 handle == RTLD_SELF) { /* ... caller included */ 3016 if (handle == RTLD_NEXT) 3017 obj = obj->next; 3018 for (; obj != NULL; obj = obj->next) { 3019 res = symlook_obj(&req, obj); 3020 if (res == 0) { 3021 if (def == NULL || 3022 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3023 def = req.sym_out; 3024 defobj = req.defobj_out; 3025 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3026 break; 3027 } 3028 } 3029 } 3030 /* 3031 * Search the dynamic linker itself, and possibly resolve the 3032 * symbol from there. This is how the application links to 3033 * dynamic linker services such as dlopen. 3034 */ 3035 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3036 res = symlook_obj(&req, &obj_rtld); 3037 if (res == 0 && is_exported(req.sym_out)) { 3038 def = req.sym_out; 3039 defobj = req.defobj_out; 3040 } 3041 } 3042 } else { 3043 assert(handle == RTLD_DEFAULT); 3044 res = symlook_default(&req, obj); 3045 if (res == 0) { 3046 defobj = req.defobj_out; 3047 def = req.sym_out; 3048 } 3049 } 3050 } else { 3051 if ((obj = dlcheck(handle)) == NULL) { 3052 lock_release(rtld_bind_lock, &lockstate); 3053 return NULL; 3054 } 3055 3056 donelist_init(&donelist); 3057 if (obj->mainprog) { 3058 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3059 res = symlook_global(&req, &donelist); 3060 if (res == 0) { 3061 def = req.sym_out; 3062 defobj = req.defobj_out; 3063 } 3064 /* 3065 * Search the dynamic linker itself, and possibly resolve the 3066 * symbol from there. This is how the application links to 3067 * dynamic linker services such as dlopen. 3068 */ 3069 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3070 res = symlook_obj(&req, &obj_rtld); 3071 if (res == 0) { 3072 def = req.sym_out; 3073 defobj = req.defobj_out; 3074 } 3075 } 3076 } 3077 else { 3078 /* Search the whole DAG rooted at the given object. */ 3079 res = symlook_list(&req, &obj->dagmembers, &donelist); 3080 if (res == 0) { 3081 def = req.sym_out; 3082 defobj = req.defobj_out; 3083 } 3084 } 3085 } 3086 3087 if (def != NULL) { 3088 lock_release(rtld_bind_lock, &lockstate); 3089 3090 /* 3091 * The value required by the caller is derived from the value 3092 * of the symbol. For the ia64 architecture, we need to 3093 * construct a function descriptor which the caller can use to 3094 * call the function with the right 'gp' value. For other 3095 * architectures and for non-functions, the value is simply 3096 * the relocated value of the symbol. 3097 */ 3098 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3099 return (make_function_pointer(def, defobj)); 3100 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3101 return (rtld_resolve_ifunc(defobj, def)); 3102 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3103 tls_index ti; 3104 ti.ti_module = defobj->tlsindex; 3105 ti.ti_offset = def->st_value; 3106 return (__tls_get_addr(&ti)); 3107 } else 3108 return (defobj->relocbase + def->st_value); 3109 } 3110 3111 _rtld_error("Undefined symbol \"%s\"", name); 3112 lock_release(rtld_bind_lock, &lockstate); 3113 return NULL; 3114 } 3115 3116 void * 3117 dlsym(void *handle, const char *name) 3118 { 3119 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3120 SYMLOOK_DLSYM); 3121 } 3122 3123 dlfunc_t 3124 dlfunc(void *handle, const char *name) 3125 { 3126 union { 3127 void *d; 3128 dlfunc_t f; 3129 } rv; 3130 3131 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3132 SYMLOOK_DLSYM); 3133 return (rv.f); 3134 } 3135 3136 void * 3137 dlvsym(void *handle, const char *name, const char *version) 3138 { 3139 Ver_Entry ventry; 3140 3141 ventry.name = version; 3142 ventry.file = NULL; 3143 ventry.hash = elf_hash(version); 3144 ventry.flags= 0; 3145 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3146 SYMLOOK_DLSYM); 3147 } 3148 3149 int 3150 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3151 { 3152 const Obj_Entry *obj; 3153 RtldLockState lockstate; 3154 3155 rlock_acquire(rtld_bind_lock, &lockstate); 3156 obj = obj_from_addr(addr); 3157 if (obj == NULL) { 3158 _rtld_error("No shared object contains address"); 3159 lock_release(rtld_bind_lock, &lockstate); 3160 return (0); 3161 } 3162 rtld_fill_dl_phdr_info(obj, phdr_info); 3163 lock_release(rtld_bind_lock, &lockstate); 3164 return (1); 3165 } 3166 3167 int 3168 dladdr(const void *addr, Dl_info *info) 3169 { 3170 const Obj_Entry *obj; 3171 const Elf_Sym *def; 3172 void *symbol_addr; 3173 unsigned long symoffset; 3174 RtldLockState lockstate; 3175 3176 rlock_acquire(rtld_bind_lock, &lockstate); 3177 obj = obj_from_addr(addr); 3178 if (obj == NULL) { 3179 _rtld_error("No shared object contains address"); 3180 lock_release(rtld_bind_lock, &lockstate); 3181 return 0; 3182 } 3183 info->dli_fname = obj->path; 3184 info->dli_fbase = obj->mapbase; 3185 info->dli_saddr = NULL; 3186 info->dli_sname = NULL; 3187 3188 /* 3189 * Walk the symbol list looking for the symbol whose address is 3190 * closest to the address sent in. 3191 */ 3192 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3193 def = obj->symtab + symoffset; 3194 3195 /* 3196 * For skip the symbol if st_shndx is either SHN_UNDEF or 3197 * SHN_COMMON. 3198 */ 3199 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3200 continue; 3201 3202 /* 3203 * If the symbol is greater than the specified address, or if it 3204 * is further away from addr than the current nearest symbol, 3205 * then reject it. 3206 */ 3207 symbol_addr = obj->relocbase + def->st_value; 3208 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3209 continue; 3210 3211 /* Update our idea of the nearest symbol. */ 3212 info->dli_sname = obj->strtab + def->st_name; 3213 info->dli_saddr = symbol_addr; 3214 3215 /* Exact match? */ 3216 if (info->dli_saddr == addr) 3217 break; 3218 } 3219 lock_release(rtld_bind_lock, &lockstate); 3220 return 1; 3221 } 3222 3223 int 3224 dlinfo(void *handle, int request, void *p) 3225 { 3226 const Obj_Entry *obj; 3227 RtldLockState lockstate; 3228 int error; 3229 3230 rlock_acquire(rtld_bind_lock, &lockstate); 3231 3232 if (handle == NULL || handle == RTLD_SELF) { 3233 void *retaddr; 3234 3235 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3236 if ((obj = obj_from_addr(retaddr)) == NULL) 3237 _rtld_error("Cannot determine caller's shared object"); 3238 } else 3239 obj = dlcheck(handle); 3240 3241 if (obj == NULL) { 3242 lock_release(rtld_bind_lock, &lockstate); 3243 return (-1); 3244 } 3245 3246 error = 0; 3247 switch (request) { 3248 case RTLD_DI_LINKMAP: 3249 *((struct link_map const **)p) = &obj->linkmap; 3250 break; 3251 case RTLD_DI_ORIGIN: 3252 error = rtld_dirname(obj->path, p); 3253 break; 3254 3255 case RTLD_DI_SERINFOSIZE: 3256 case RTLD_DI_SERINFO: 3257 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3258 break; 3259 3260 default: 3261 _rtld_error("Invalid request %d passed to dlinfo()", request); 3262 error = -1; 3263 } 3264 3265 lock_release(rtld_bind_lock, &lockstate); 3266 3267 return (error); 3268 } 3269 3270 static void 3271 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3272 { 3273 3274 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3275 phdr_info->dlpi_name = STAILQ_FIRST(&obj->names) ? 3276 STAILQ_FIRST(&obj->names)->name : obj->path; 3277 phdr_info->dlpi_phdr = obj->phdr; 3278 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3279 phdr_info->dlpi_tls_modid = obj->tlsindex; 3280 phdr_info->dlpi_tls_data = obj->tlsinit; 3281 phdr_info->dlpi_adds = obj_loads; 3282 phdr_info->dlpi_subs = obj_loads - obj_count; 3283 } 3284 3285 int 3286 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3287 { 3288 struct dl_phdr_info phdr_info; 3289 const Obj_Entry *obj; 3290 RtldLockState bind_lockstate, phdr_lockstate; 3291 int error; 3292 3293 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3294 rlock_acquire(rtld_bind_lock, &bind_lockstate); 3295 3296 error = 0; 3297 3298 for (obj = obj_list; obj != NULL; obj = obj->next) { 3299 rtld_fill_dl_phdr_info(obj, &phdr_info); 3300 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0) 3301 break; 3302 3303 } 3304 lock_release(rtld_bind_lock, &bind_lockstate); 3305 lock_release(rtld_phdr_lock, &phdr_lockstate); 3306 3307 return (error); 3308 } 3309 3310 static void * 3311 fill_search_info(const char *dir, size_t dirlen, void *param) 3312 { 3313 struct fill_search_info_args *arg; 3314 3315 arg = param; 3316 3317 if (arg->request == RTLD_DI_SERINFOSIZE) { 3318 arg->serinfo->dls_cnt ++; 3319 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3320 } else { 3321 struct dl_serpath *s_entry; 3322 3323 s_entry = arg->serpath; 3324 s_entry->dls_name = arg->strspace; 3325 s_entry->dls_flags = arg->flags; 3326 3327 strncpy(arg->strspace, dir, dirlen); 3328 arg->strspace[dirlen] = '\0'; 3329 3330 arg->strspace += dirlen + 1; 3331 arg->serpath++; 3332 } 3333 3334 return (NULL); 3335 } 3336 3337 static int 3338 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3339 { 3340 struct dl_serinfo _info; 3341 struct fill_search_info_args args; 3342 3343 args.request = RTLD_DI_SERINFOSIZE; 3344 args.serinfo = &_info; 3345 3346 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3347 _info.dls_cnt = 0; 3348 3349 path_enumerate(obj->rpath, fill_search_info, &args); 3350 path_enumerate(ld_library_path, fill_search_info, &args); 3351 path_enumerate(obj->runpath, fill_search_info, &args); 3352 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args); 3353 if (!obj->z_nodeflib) 3354 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 3355 3356 3357 if (request == RTLD_DI_SERINFOSIZE) { 3358 info->dls_size = _info.dls_size; 3359 info->dls_cnt = _info.dls_cnt; 3360 return (0); 3361 } 3362 3363 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3364 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3365 return (-1); 3366 } 3367 3368 args.request = RTLD_DI_SERINFO; 3369 args.serinfo = info; 3370 args.serpath = &info->dls_serpath[0]; 3371 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3372 3373 args.flags = LA_SER_RUNPATH; 3374 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 3375 return (-1); 3376 3377 args.flags = LA_SER_LIBPATH; 3378 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 3379 return (-1); 3380 3381 args.flags = LA_SER_RUNPATH; 3382 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL) 3383 return (-1); 3384 3385 args.flags = LA_SER_CONFIG; 3386 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args) 3387 != NULL) 3388 return (-1); 3389 3390 args.flags = LA_SER_DEFAULT; 3391 if (!obj->z_nodeflib && 3392 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 3393 return (-1); 3394 return (0); 3395 } 3396 3397 static int 3398 rtld_dirname(const char *path, char *bname) 3399 { 3400 const char *endp; 3401 3402 /* Empty or NULL string gets treated as "." */ 3403 if (path == NULL || *path == '\0') { 3404 bname[0] = '.'; 3405 bname[1] = '\0'; 3406 return (0); 3407 } 3408 3409 /* Strip trailing slashes */ 3410 endp = path + strlen(path) - 1; 3411 while (endp > path && *endp == '/') 3412 endp--; 3413 3414 /* Find the start of the dir */ 3415 while (endp > path && *endp != '/') 3416 endp--; 3417 3418 /* Either the dir is "/" or there are no slashes */ 3419 if (endp == path) { 3420 bname[0] = *endp == '/' ? '/' : '.'; 3421 bname[1] = '\0'; 3422 return (0); 3423 } else { 3424 do { 3425 endp--; 3426 } while (endp > path && *endp == '/'); 3427 } 3428 3429 if (endp - path + 2 > PATH_MAX) 3430 { 3431 _rtld_error("Filename is too long: %s", path); 3432 return(-1); 3433 } 3434 3435 strncpy(bname, path, endp - path + 1); 3436 bname[endp - path + 1] = '\0'; 3437 return (0); 3438 } 3439 3440 static int 3441 rtld_dirname_abs(const char *path, char *base) 3442 { 3443 char base_rel[PATH_MAX]; 3444 3445 if (rtld_dirname(path, base) == -1) 3446 return (-1); 3447 if (base[0] == '/') 3448 return (0); 3449 if (getcwd(base_rel, sizeof(base_rel)) == NULL || 3450 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) || 3451 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel)) 3452 return (-1); 3453 strcpy(base, base_rel); 3454 return (0); 3455 } 3456 3457 static void 3458 linkmap_add(Obj_Entry *obj) 3459 { 3460 struct link_map *l = &obj->linkmap; 3461 struct link_map *prev; 3462 3463 obj->linkmap.l_name = obj->path; 3464 obj->linkmap.l_addr = obj->mapbase; 3465 obj->linkmap.l_ld = obj->dynamic; 3466 #ifdef __mips__ 3467 /* GDB needs load offset on MIPS to use the symbols */ 3468 obj->linkmap.l_offs = obj->relocbase; 3469 #endif 3470 3471 if (r_debug.r_map == NULL) { 3472 r_debug.r_map = l; 3473 return; 3474 } 3475 3476 /* 3477 * Scan to the end of the list, but not past the entry for the 3478 * dynamic linker, which we want to keep at the very end. 3479 */ 3480 for (prev = r_debug.r_map; 3481 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3482 prev = prev->l_next) 3483 ; 3484 3485 /* Link in the new entry. */ 3486 l->l_prev = prev; 3487 l->l_next = prev->l_next; 3488 if (l->l_next != NULL) 3489 l->l_next->l_prev = l; 3490 prev->l_next = l; 3491 } 3492 3493 static void 3494 linkmap_delete(Obj_Entry *obj) 3495 { 3496 struct link_map *l = &obj->linkmap; 3497 3498 if (l->l_prev == NULL) { 3499 if ((r_debug.r_map = l->l_next) != NULL) 3500 l->l_next->l_prev = NULL; 3501 return; 3502 } 3503 3504 if ((l->l_prev->l_next = l->l_next) != NULL) 3505 l->l_next->l_prev = l->l_prev; 3506 } 3507 3508 /* 3509 * Function for the debugger to set a breakpoint on to gain control. 3510 * 3511 * The two parameters allow the debugger to easily find and determine 3512 * what the runtime loader is doing and to whom it is doing it. 3513 * 3514 * When the loadhook trap is hit (r_debug_state, set at program 3515 * initialization), the arguments can be found on the stack: 3516 * 3517 * +8 struct link_map *m 3518 * +4 struct r_debug *rd 3519 * +0 RetAddr 3520 */ 3521 void 3522 r_debug_state(struct r_debug* rd, struct link_map *m) 3523 { 3524 /* 3525 * The following is a hack to force the compiler to emit calls to 3526 * this function, even when optimizing. If the function is empty, 3527 * the compiler is not obliged to emit any code for calls to it, 3528 * even when marked __noinline. However, gdb depends on those 3529 * calls being made. 3530 */ 3531 __asm __volatile("" : : : "memory"); 3532 } 3533 3534 /* 3535 * Get address of the pointer variable in the main program. 3536 * Prefer non-weak symbol over the weak one. 3537 */ 3538 static const void ** 3539 get_program_var_addr(const char *name, RtldLockState *lockstate) 3540 { 3541 SymLook req; 3542 DoneList donelist; 3543 3544 symlook_init(&req, name); 3545 req.lockstate = lockstate; 3546 donelist_init(&donelist); 3547 if (symlook_global(&req, &donelist) != 0) 3548 return (NULL); 3549 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 3550 return ((const void **)make_function_pointer(req.sym_out, 3551 req.defobj_out)); 3552 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 3553 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 3554 else 3555 return ((const void **)(req.defobj_out->relocbase + req.sym_out->st_value)); 3556 } 3557 3558 /* 3559 * Set a pointer variable in the main program to the given value. This 3560 * is used to set key variables such as "environ" before any of the 3561 * init functions are called. 3562 */ 3563 static void 3564 set_program_var(const char *name, const void *value) 3565 { 3566 const void **addr; 3567 3568 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 3569 dbg("\"%s\": *%p <-- %p", name, addr, value); 3570 *addr = value; 3571 } 3572 } 3573 3574 /* 3575 * Search the global objects, including dependencies and main object, 3576 * for the given symbol. 3577 */ 3578 static int 3579 symlook_global(SymLook *req, DoneList *donelist) 3580 { 3581 SymLook req1; 3582 const Objlist_Entry *elm; 3583 int res; 3584 3585 symlook_init_from_req(&req1, req); 3586 3587 /* Search all objects loaded at program start up. */ 3588 if (req->defobj_out == NULL || 3589 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3590 res = symlook_list(&req1, &list_main, donelist); 3591 if (res == 0 && (req->defobj_out == NULL || 3592 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3593 req->sym_out = req1.sym_out; 3594 req->defobj_out = req1.defobj_out; 3595 assert(req->defobj_out != NULL); 3596 } 3597 } 3598 3599 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 3600 STAILQ_FOREACH(elm, &list_global, link) { 3601 if (req->defobj_out != NULL && 3602 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3603 break; 3604 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 3605 if (res == 0 && (req->defobj_out == NULL || 3606 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3607 req->sym_out = req1.sym_out; 3608 req->defobj_out = req1.defobj_out; 3609 assert(req->defobj_out != NULL); 3610 } 3611 } 3612 3613 return (req->sym_out != NULL ? 0 : ESRCH); 3614 } 3615 3616 /* 3617 * This is a special version of getenv which is far more efficient 3618 * at finding LD_ environment vars. 3619 */ 3620 static 3621 const char * 3622 _getenv_ld(const char *id) 3623 { 3624 const char *envp; 3625 int i, j; 3626 int idlen = strlen(id); 3627 3628 if (ld_index == LD_ARY_CACHE) 3629 return(getenv(id)); 3630 if (ld_index == 0) { 3631 for (i = j = 0; (envp = environ[i]) != NULL && j < LD_ARY_CACHE; ++i) { 3632 if (envp[0] == 'L' && envp[1] == 'D' && envp[2] == '_') 3633 ld_ary[j++] = envp; 3634 } 3635 if (j == 0) 3636 ld_ary[j++] = ""; 3637 ld_index = j; 3638 } 3639 for (i = ld_index - 1; i >= 0; --i) { 3640 if (strncmp(ld_ary[i], id, idlen) == 0 && ld_ary[i][idlen] == '=') 3641 return(ld_ary[i] + idlen + 1); 3642 } 3643 return(NULL); 3644 } 3645 3646 /* 3647 * Given a symbol name in a referencing object, find the corresponding 3648 * definition of the symbol. Returns a pointer to the symbol, or NULL if 3649 * no definition was found. Returns a pointer to the Obj_Entry of the 3650 * defining object via the reference parameter DEFOBJ_OUT. 3651 */ 3652 static int 3653 symlook_default(SymLook *req, const Obj_Entry *refobj) 3654 { 3655 DoneList donelist; 3656 const Objlist_Entry *elm; 3657 SymLook req1; 3658 int res; 3659 3660 donelist_init(&donelist); 3661 symlook_init_from_req(&req1, req); 3662 3663 /* Look first in the referencing object if linked symbolically. */ 3664 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 3665 res = symlook_obj(&req1, refobj); 3666 if (res == 0) { 3667 req->sym_out = req1.sym_out; 3668 req->defobj_out = req1.defobj_out; 3669 assert(req->defobj_out != NULL); 3670 } 3671 } 3672 3673 symlook_global(req, &donelist); 3674 3675 /* Search all dlopened DAGs containing the referencing object. */ 3676 STAILQ_FOREACH(elm, &refobj->dldags, link) { 3677 if (req->sym_out != NULL && 3678 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3679 break; 3680 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 3681 if (res == 0 && (req->sym_out == NULL || 3682 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3683 req->sym_out = req1.sym_out; 3684 req->defobj_out = req1.defobj_out; 3685 assert(req->defobj_out != NULL); 3686 } 3687 } 3688 3689 /* 3690 * Search the dynamic linker itself, and possibly resolve the 3691 * symbol from there. This is how the application links to 3692 * dynamic linker services such as dlopen. Only the values listed 3693 * in the "exports" array can be resolved from the dynamic linker. 3694 */ 3695 if (req->sym_out == NULL || 3696 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3697 res = symlook_obj(&req1, &obj_rtld); 3698 if (res == 0 && is_exported(req1.sym_out)) { 3699 req->sym_out = req1.sym_out; 3700 req->defobj_out = req1.defobj_out; 3701 assert(req->defobj_out != NULL); 3702 } 3703 } 3704 3705 return (req->sym_out != NULL ? 0 : ESRCH); 3706 } 3707 3708 static int 3709 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 3710 { 3711 const Elf_Sym *def; 3712 const Obj_Entry *defobj; 3713 const Objlist_Entry *elm; 3714 SymLook req1; 3715 int res; 3716 3717 def = NULL; 3718 defobj = NULL; 3719 STAILQ_FOREACH(elm, objlist, link) { 3720 if (donelist_check(dlp, elm->obj)) 3721 continue; 3722 symlook_init_from_req(&req1, req); 3723 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 3724 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3725 def = req1.sym_out; 3726 defobj = req1.defobj_out; 3727 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3728 break; 3729 } 3730 } 3731 } 3732 if (def != NULL) { 3733 req->sym_out = def; 3734 req->defobj_out = defobj; 3735 return (0); 3736 } 3737 return (ESRCH); 3738 } 3739 3740 /* 3741 * Search the chain of DAGS cointed to by the given Needed_Entry 3742 * for a symbol of the given name. Each DAG is scanned completely 3743 * before advancing to the next one. Returns a pointer to the symbol, 3744 * or NULL if no definition was found. 3745 */ 3746 static int 3747 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 3748 { 3749 const Elf_Sym *def; 3750 const Needed_Entry *n; 3751 const Obj_Entry *defobj; 3752 SymLook req1; 3753 int res; 3754 3755 def = NULL; 3756 defobj = NULL; 3757 symlook_init_from_req(&req1, req); 3758 for (n = needed; n != NULL; n = n->next) { 3759 if (n->obj == NULL || 3760 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 3761 continue; 3762 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3763 def = req1.sym_out; 3764 defobj = req1.defobj_out; 3765 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3766 break; 3767 } 3768 } 3769 if (def != NULL) { 3770 req->sym_out = def; 3771 req->defobj_out = defobj; 3772 return (0); 3773 } 3774 return (ESRCH); 3775 } 3776 3777 /* 3778 * Search the symbol table of a single shared object for a symbol of 3779 * the given name and version, if requested. Returns a pointer to the 3780 * symbol, or NULL if no definition was found. If the object is 3781 * filter, return filtered symbol from filtee. 3782 * 3783 * The symbol's hash value is passed in for efficiency reasons; that 3784 * eliminates many recomputations of the hash value. 3785 */ 3786 int 3787 symlook_obj(SymLook *req, const Obj_Entry *obj) 3788 { 3789 DoneList donelist; 3790 SymLook req1; 3791 int flags, res, mres; 3792 3793 /* 3794 * There is at least one valid hash at this point, and we prefer to use 3795 * the faster GNU version if available. 3796 */ 3797 if (obj->valid_hash_gnu) 3798 mres = symlook_obj1_gnu(req, obj); 3799 else 3800 mres = symlook_obj1_sysv(req, obj); 3801 3802 if (mres == 0) { 3803 if (obj->needed_filtees != NULL) { 3804 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3805 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3806 donelist_init(&donelist); 3807 symlook_init_from_req(&req1, req); 3808 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 3809 if (res == 0) { 3810 req->sym_out = req1.sym_out; 3811 req->defobj_out = req1.defobj_out; 3812 } 3813 return (res); 3814 } 3815 if (obj->needed_aux_filtees != NULL) { 3816 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3817 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3818 donelist_init(&donelist); 3819 symlook_init_from_req(&req1, req); 3820 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 3821 if (res == 0) { 3822 req->sym_out = req1.sym_out; 3823 req->defobj_out = req1.defobj_out; 3824 return (res); 3825 } 3826 } 3827 } 3828 return (mres); 3829 } 3830 3831 /* Symbol match routine common to both hash functions */ 3832 static bool 3833 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 3834 const unsigned long symnum) 3835 { 3836 Elf_Versym verndx; 3837 const Elf_Sym *symp; 3838 const char *strp; 3839 3840 symp = obj->symtab + symnum; 3841 strp = obj->strtab + symp->st_name; 3842 3843 switch (ELF_ST_TYPE(symp->st_info)) { 3844 case STT_FUNC: 3845 case STT_NOTYPE: 3846 case STT_OBJECT: 3847 case STT_COMMON: 3848 case STT_GNU_IFUNC: 3849 if (symp->st_value == 0) 3850 return (false); 3851 /* fallthrough */ 3852 case STT_TLS: 3853 if (symp->st_shndx != SHN_UNDEF) 3854 break; 3855 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 3856 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 3857 break; 3858 /* fallthrough */ 3859 default: 3860 return (false); 3861 } 3862 if (strcmp(req->name, strp) != 0) 3863 return (false); 3864 3865 if (req->ventry == NULL) { 3866 if (obj->versyms != NULL) { 3867 verndx = VER_NDX(obj->versyms[symnum]); 3868 if (verndx > obj->vernum) { 3869 _rtld_error( 3870 "%s: symbol %s references wrong version %d", 3871 obj->path, obj->strtab + symnum, verndx); 3872 return (false); 3873 } 3874 /* 3875 * If we are not called from dlsym (i.e. this 3876 * is a normal relocation from unversioned 3877 * binary), accept the symbol immediately if 3878 * it happens to have first version after this 3879 * shared object became versioned. Otherwise, 3880 * if symbol is versioned and not hidden, 3881 * remember it. If it is the only symbol with 3882 * this name exported by the shared object, it 3883 * will be returned as a match by the calling 3884 * function. If symbol is global (verndx < 2) 3885 * accept it unconditionally. 3886 */ 3887 if ((req->flags & SYMLOOK_DLSYM) == 0 && 3888 verndx == VER_NDX_GIVEN) { 3889 result->sym_out = symp; 3890 return (true); 3891 } 3892 else if (verndx >= VER_NDX_GIVEN) { 3893 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 3894 == 0) { 3895 if (result->vsymp == NULL) 3896 result->vsymp = symp; 3897 result->vcount++; 3898 } 3899 return (false); 3900 } 3901 } 3902 result->sym_out = symp; 3903 return (true); 3904 } 3905 if (obj->versyms == NULL) { 3906 if (object_match_name(obj, req->ventry->name)) { 3907 _rtld_error("%s: object %s should provide version %s " 3908 "for symbol %s", obj_rtld.path, obj->path, 3909 req->ventry->name, obj->strtab + symnum); 3910 return (false); 3911 } 3912 } else { 3913 verndx = VER_NDX(obj->versyms[symnum]); 3914 if (verndx > obj->vernum) { 3915 _rtld_error("%s: symbol %s references wrong version %d", 3916 obj->path, obj->strtab + symnum, verndx); 3917 return (false); 3918 } 3919 if (obj->vertab[verndx].hash != req->ventry->hash || 3920 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 3921 /* 3922 * Version does not match. Look if this is a 3923 * global symbol and if it is not hidden. If 3924 * global symbol (verndx < 2) is available, 3925 * use it. Do not return symbol if we are 3926 * called by dlvsym, because dlvsym looks for 3927 * a specific version and default one is not 3928 * what dlvsym wants. 3929 */ 3930 if ((req->flags & SYMLOOK_DLSYM) || 3931 (verndx >= VER_NDX_GIVEN) || 3932 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 3933 return (false); 3934 } 3935 } 3936 result->sym_out = symp; 3937 return (true); 3938 } 3939 3940 /* 3941 * Search for symbol using SysV hash function. 3942 * obj->buckets is known not to be NULL at this point; the test for this was 3943 * performed with the obj->valid_hash_sysv assignment. 3944 */ 3945 static int 3946 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 3947 { 3948 unsigned long symnum; 3949 Sym_Match_Result matchres; 3950 3951 matchres.sym_out = NULL; 3952 matchres.vsymp = NULL; 3953 matchres.vcount = 0; 3954 3955 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 3956 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 3957 if (symnum >= obj->nchains) 3958 return (ESRCH); /* Bad object */ 3959 3960 if (matched_symbol(req, obj, &matchres, symnum)) { 3961 req->sym_out = matchres.sym_out; 3962 req->defobj_out = obj; 3963 return (0); 3964 } 3965 } 3966 if (matchres.vcount == 1) { 3967 req->sym_out = matchres.vsymp; 3968 req->defobj_out = obj; 3969 return (0); 3970 } 3971 return (ESRCH); 3972 } 3973 3974 /* Search for symbol using GNU hash function */ 3975 static int 3976 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 3977 { 3978 Elf_Addr bloom_word; 3979 const Elf32_Word *hashval; 3980 Elf32_Word bucket; 3981 Sym_Match_Result matchres; 3982 unsigned int h1, h2; 3983 unsigned long symnum; 3984 3985 matchres.sym_out = NULL; 3986 matchres.vsymp = NULL; 3987 matchres.vcount = 0; 3988 3989 /* Pick right bitmask word from Bloom filter array */ 3990 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 3991 obj->maskwords_bm_gnu]; 3992 3993 /* Calculate modulus word size of gnu hash and its derivative */ 3994 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 3995 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 3996 3997 /* Filter out the "definitely not in set" queries */ 3998 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 3999 return (ESRCH); 4000 4001 /* Locate hash chain and corresponding value element*/ 4002 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4003 if (bucket == 0) 4004 return (ESRCH); 4005 hashval = &obj->chain_zero_gnu[bucket]; 4006 do { 4007 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4008 symnum = hashval - obj->chain_zero_gnu; 4009 if (matched_symbol(req, obj, &matchres, symnum)) { 4010 req->sym_out = matchres.sym_out; 4011 req->defobj_out = obj; 4012 return (0); 4013 } 4014 } 4015 } while ((*hashval++ & 1) == 0); 4016 if (matchres.vcount == 1) { 4017 req->sym_out = matchres.vsymp; 4018 req->defobj_out = obj; 4019 return (0); 4020 } 4021 return (ESRCH); 4022 } 4023 4024 static void 4025 trace_loaded_objects(Obj_Entry *obj) 4026 { 4027 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4028 int c; 4029 4030 if ((main_local = _getenv_ld("LD_TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 4031 main_local = ""; 4032 4033 if ((fmt1 = _getenv_ld("LD_TRACE_LOADED_OBJECTS_FMT1")) == NULL) 4034 fmt1 = "\t%o => %p (%x)\n"; 4035 4036 if ((fmt2 = _getenv_ld("LD_TRACE_LOADED_OBJECTS_FMT2")) == NULL) 4037 fmt2 = "\t%o (%x)\n"; 4038 4039 list_containers = _getenv_ld("LD_TRACE_LOADED_OBJECTS_ALL"); 4040 4041 for (; obj; obj = obj->next) { 4042 Needed_Entry *needed; 4043 char *name, *path; 4044 bool is_lib; 4045 4046 if (list_containers && obj->needed != NULL) 4047 rtld_printf("%s:\n", obj->path); 4048 for (needed = obj->needed; needed; needed = needed->next) { 4049 if (needed->obj != NULL) { 4050 if (needed->obj->traced && !list_containers) 4051 continue; 4052 needed->obj->traced = true; 4053 path = needed->obj->path; 4054 } else 4055 path = "not found"; 4056 4057 name = (char *)obj->strtab + needed->name; 4058 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4059 4060 fmt = is_lib ? fmt1 : fmt2; 4061 while ((c = *fmt++) != '\0') { 4062 switch (c) { 4063 default: 4064 rtld_putchar(c); 4065 continue; 4066 case '\\': 4067 switch (c = *fmt) { 4068 case '\0': 4069 continue; 4070 case 'n': 4071 rtld_putchar('\n'); 4072 break; 4073 case 't': 4074 rtld_putchar('\t'); 4075 break; 4076 } 4077 break; 4078 case '%': 4079 switch (c = *fmt) { 4080 case '\0': 4081 continue; 4082 case '%': 4083 default: 4084 rtld_putchar(c); 4085 break; 4086 case 'A': 4087 rtld_putstr(main_local); 4088 break; 4089 case 'a': 4090 rtld_putstr(obj_main->path); 4091 break; 4092 case 'o': 4093 rtld_putstr(name); 4094 break; 4095 case 'p': 4096 rtld_putstr(path); 4097 break; 4098 case 'x': 4099 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4100 0); 4101 break; 4102 } 4103 break; 4104 } 4105 ++fmt; 4106 } 4107 } 4108 } 4109 } 4110 4111 /* 4112 * Unload a dlopened object and its dependencies from memory and from 4113 * our data structures. It is assumed that the DAG rooted in the 4114 * object has already been unreferenced, and that the object has a 4115 * reference count of 0. 4116 */ 4117 static void 4118 unload_object(Obj_Entry *root) 4119 { 4120 Obj_Entry *obj; 4121 Obj_Entry **linkp; 4122 4123 assert(root->refcount == 0); 4124 4125 /* 4126 * Pass over the DAG removing unreferenced objects from 4127 * appropriate lists. 4128 */ 4129 unlink_object(root); 4130 4131 /* Unmap all objects that are no longer referenced. */ 4132 linkp = &obj_list->next; 4133 while ((obj = *linkp) != NULL) { 4134 if (obj->refcount == 0) { 4135 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 4136 obj->path); 4137 dbg("unloading \"%s\"", obj->path); 4138 unload_filtees(root); 4139 munmap(obj->mapbase, obj->mapsize); 4140 linkmap_delete(obj); 4141 *linkp = obj->next; 4142 obj_count--; 4143 obj_free(obj); 4144 } else 4145 linkp = &obj->next; 4146 } 4147 obj_tail = linkp; 4148 } 4149 4150 static void 4151 unlink_object(Obj_Entry *root) 4152 { 4153 Objlist_Entry *elm; 4154 4155 if (root->refcount == 0) { 4156 /* Remove the object from the RTLD_GLOBAL list. */ 4157 objlist_remove(&list_global, root); 4158 4159 /* Remove the object from all objects' DAG lists. */ 4160 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4161 objlist_remove(&elm->obj->dldags, root); 4162 if (elm->obj != root) 4163 unlink_object(elm->obj); 4164 } 4165 } 4166 } 4167 4168 static void 4169 ref_dag(Obj_Entry *root) 4170 { 4171 Objlist_Entry *elm; 4172 4173 assert(root->dag_inited); 4174 STAILQ_FOREACH(elm, &root->dagmembers, link) 4175 elm->obj->refcount++; 4176 } 4177 4178 static void 4179 unref_dag(Obj_Entry *root) 4180 { 4181 Objlist_Entry *elm; 4182 4183 assert(root->dag_inited); 4184 STAILQ_FOREACH(elm, &root->dagmembers, link) 4185 elm->obj->refcount--; 4186 } 4187 4188 /* 4189 * Common code for MD __tls_get_addr(). 4190 */ 4191 void * 4192 tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset) 4193 { 4194 Elf_Addr* dtv = *dtvp; 4195 RtldLockState lockstate; 4196 4197 /* Check dtv generation in case new modules have arrived */ 4198 if (dtv[0] != tls_dtv_generation) { 4199 Elf_Addr* newdtv; 4200 int to_copy; 4201 4202 wlock_acquire(rtld_bind_lock, &lockstate); 4203 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4204 to_copy = dtv[1]; 4205 if (to_copy > tls_max_index) 4206 to_copy = tls_max_index; 4207 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4208 newdtv[0] = tls_dtv_generation; 4209 newdtv[1] = tls_max_index; 4210 free(dtv); 4211 lock_release(rtld_bind_lock, &lockstate); 4212 dtv = *dtvp = newdtv; 4213 } 4214 4215 /* Dynamically allocate module TLS if necessary */ 4216 if (!dtv[index + 1]) { 4217 /* Signal safe, wlock will block out signals. */ 4218 wlock_acquire(rtld_bind_lock, &lockstate); 4219 if (!dtv[index + 1]) 4220 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4221 lock_release(rtld_bind_lock, &lockstate); 4222 } 4223 return (void*) (dtv[index + 1] + offset); 4224 } 4225 4226 #if defined(RTLD_STATIC_TLS_VARIANT_II) 4227 4228 /* 4229 * Allocate the static TLS area. Return a pointer to the TCB. The 4230 * static area is based on negative offsets relative to the tcb. 4231 * 4232 * The TCB contains an errno pointer for the system call layer, but because 4233 * we are the RTLD we really have no idea how the caller was compiled so 4234 * the information has to be passed in. errno can either be: 4235 * 4236 * type 0 errno is a simple non-TLS global pointer. 4237 * (special case for e.g. libc_rtld) 4238 * type 1 errno accessed by GOT entry (dynamically linked programs) 4239 * type 2 errno accessed by %gs:OFFSET (statically linked programs) 4240 */ 4241 struct tls_tcb * 4242 allocate_tls(Obj_Entry *objs) 4243 { 4244 Obj_Entry *obj; 4245 size_t data_size; 4246 size_t dtv_size; 4247 struct tls_tcb *tcb; 4248 Elf_Addr *dtv; 4249 Elf_Addr addr; 4250 4251 /* 4252 * Allocate the new TCB. static TLS storage is placed just before the 4253 * TCB to support the %gs:OFFSET (negative offset) model. 4254 */ 4255 data_size = (tls_static_space + RTLD_STATIC_TLS_ALIGN_MASK) & 4256 ~RTLD_STATIC_TLS_ALIGN_MASK; 4257 tcb = malloc(data_size + sizeof(*tcb)); 4258 tcb = (void *)((char *)tcb + data_size); /* actual tcb location */ 4259 4260 dtv_size = (tls_max_index + 2) * sizeof(Elf_Addr); 4261 dtv = malloc(dtv_size); 4262 bzero(dtv, dtv_size); 4263 4264 #ifdef RTLD_TCB_HAS_SELF_POINTER 4265 tcb->tcb_self = tcb; 4266 #endif 4267 tcb->tcb_dtv = dtv; 4268 tcb->tcb_pthread = NULL; 4269 4270 dtv[0] = tls_dtv_generation; 4271 dtv[1] = tls_max_index; 4272 4273 for (obj = objs; obj; obj = obj->next) { 4274 if (obj->tlsoffset) { 4275 addr = (Elf_Addr)tcb - obj->tlsoffset; 4276 memset((void *)(addr + obj->tlsinitsize), 4277 0, obj->tlssize - obj->tlsinitsize); 4278 if (obj->tlsinit) 4279 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4280 dtv[obj->tlsindex + 1] = addr; 4281 } 4282 } 4283 return(tcb); 4284 } 4285 4286 void 4287 free_tls(struct tls_tcb *tcb) 4288 { 4289 Elf_Addr *dtv; 4290 int dtv_size, i; 4291 Elf_Addr tls_start, tls_end; 4292 size_t data_size; 4293 4294 data_size = (tls_static_space + RTLD_STATIC_TLS_ALIGN_MASK) & 4295 ~RTLD_STATIC_TLS_ALIGN_MASK; 4296 4297 dtv = tcb->tcb_dtv; 4298 dtv_size = dtv[1]; 4299 tls_end = (Elf_Addr)tcb; 4300 tls_start = (Elf_Addr)tcb - data_size; 4301 for (i = 0; i < dtv_size; i++) { 4302 if (dtv[i+2] != 0 && (dtv[i+2] < tls_start || dtv[i+2] > tls_end)) { 4303 free((void *)dtv[i+2]); 4304 } 4305 } 4306 4307 free((void*) tls_start); 4308 } 4309 4310 #else 4311 #error "Unsupported TLS layout" 4312 #endif 4313 4314 /* 4315 * Allocate TLS block for module with given index. 4316 */ 4317 void * 4318 allocate_module_tls(int index) 4319 { 4320 Obj_Entry* obj; 4321 char* p; 4322 4323 for (obj = obj_list; obj; obj = obj->next) { 4324 if (obj->tlsindex == index) 4325 break; 4326 } 4327 if (!obj) { 4328 _rtld_error("Can't find module with TLS index %d", index); 4329 die(); 4330 } 4331 4332 p = malloc(obj->tlssize); 4333 if (p == NULL) { 4334 _rtld_error("Cannot allocate TLS block for index %d", index); 4335 die(); 4336 } 4337 memcpy(p, obj->tlsinit, obj->tlsinitsize); 4338 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 4339 4340 return p; 4341 } 4342 4343 bool 4344 allocate_tls_offset(Obj_Entry *obj) 4345 { 4346 size_t off; 4347 4348 if (obj->tls_done) 4349 return true; 4350 4351 if (obj->tlssize == 0) { 4352 obj->tls_done = true; 4353 return true; 4354 } 4355 4356 if (obj->tlsindex == 1) 4357 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 4358 else 4359 off = calculate_tls_offset(tls_last_offset, tls_last_size, 4360 obj->tlssize, obj->tlsalign); 4361 4362 /* 4363 * If we have already fixed the size of the static TLS block, we 4364 * must stay within that size. When allocating the static TLS, we 4365 * leave a small amount of space spare to be used for dynamically 4366 * loading modules which use static TLS. 4367 */ 4368 if (tls_static_space) { 4369 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 4370 return false; 4371 } 4372 4373 tls_last_offset = obj->tlsoffset = off; 4374 tls_last_size = obj->tlssize; 4375 obj->tls_done = true; 4376 4377 return true; 4378 } 4379 4380 void 4381 free_tls_offset(Obj_Entry *obj) 4382 { 4383 #ifdef RTLD_STATIC_TLS_VARIANT_II 4384 /* 4385 * If we were the last thing to allocate out of the static TLS 4386 * block, we give our space back to the 'allocator'. This is a 4387 * simplistic workaround to allow libGL.so.1 to be loaded and 4388 * unloaded multiple times. We only handle the Variant II 4389 * mechanism for now - this really needs a proper allocator. 4390 */ 4391 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 4392 == calculate_tls_end(tls_last_offset, tls_last_size)) { 4393 tls_last_offset -= obj->tlssize; 4394 tls_last_size = 0; 4395 } 4396 #endif 4397 } 4398 4399 struct tls_tcb * 4400 _rtld_allocate_tls(void) 4401 { 4402 struct tls_tcb *new_tcb; 4403 RtldLockState lockstate; 4404 4405 wlock_acquire(rtld_bind_lock, &lockstate); 4406 new_tcb = allocate_tls(obj_list); 4407 lock_release(rtld_bind_lock, &lockstate); 4408 return (new_tcb); 4409 } 4410 4411 void 4412 _rtld_free_tls(struct tls_tcb *tcb) 4413 { 4414 RtldLockState lockstate; 4415 4416 wlock_acquire(rtld_bind_lock, &lockstate); 4417 free_tls(tcb); 4418 lock_release(rtld_bind_lock, &lockstate); 4419 } 4420 4421 static void 4422 object_add_name(Obj_Entry *obj, const char *name) 4423 { 4424 Name_Entry *entry; 4425 size_t len; 4426 4427 len = strlen(name); 4428 entry = malloc(sizeof(Name_Entry) + len); 4429 4430 if (entry != NULL) { 4431 strcpy(entry->name, name); 4432 STAILQ_INSERT_TAIL(&obj->names, entry, link); 4433 } 4434 } 4435 4436 static int 4437 object_match_name(const Obj_Entry *obj, const char *name) 4438 { 4439 Name_Entry *entry; 4440 4441 STAILQ_FOREACH(entry, &obj->names, link) { 4442 if (strcmp(name, entry->name) == 0) 4443 return (1); 4444 } 4445 return (0); 4446 } 4447 4448 static Obj_Entry * 4449 locate_dependency(const Obj_Entry *obj, const char *name) 4450 { 4451 const Objlist_Entry *entry; 4452 const Needed_Entry *needed; 4453 4454 STAILQ_FOREACH(entry, &list_main, link) { 4455 if (object_match_name(entry->obj, name)) 4456 return entry->obj; 4457 } 4458 4459 for (needed = obj->needed; needed != NULL; needed = needed->next) { 4460 if (strcmp(obj->strtab + needed->name, name) == 0 || 4461 (needed->obj != NULL && object_match_name(needed->obj, name))) { 4462 /* 4463 * If there is DT_NEEDED for the name we are looking for, 4464 * we are all set. Note that object might not be found if 4465 * dependency was not loaded yet, so the function can 4466 * return NULL here. This is expected and handled 4467 * properly by the caller. 4468 */ 4469 return (needed->obj); 4470 } 4471 } 4472 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 4473 obj->path, name); 4474 die(); 4475 } 4476 4477 static int 4478 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 4479 const Elf_Vernaux *vna) 4480 { 4481 const Elf_Verdef *vd; 4482 const char *vername; 4483 4484 vername = refobj->strtab + vna->vna_name; 4485 vd = depobj->verdef; 4486 if (vd == NULL) { 4487 _rtld_error("%s: version %s required by %s not defined", 4488 depobj->path, vername, refobj->path); 4489 return (-1); 4490 } 4491 for (;;) { 4492 if (vd->vd_version != VER_DEF_CURRENT) { 4493 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4494 depobj->path, vd->vd_version); 4495 return (-1); 4496 } 4497 if (vna->vna_hash == vd->vd_hash) { 4498 const Elf_Verdaux *aux = (const Elf_Verdaux *) 4499 ((char *)vd + vd->vd_aux); 4500 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 4501 return (0); 4502 } 4503 if (vd->vd_next == 0) 4504 break; 4505 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4506 } 4507 if (vna->vna_flags & VER_FLG_WEAK) 4508 return (0); 4509 _rtld_error("%s: version %s required by %s not found", 4510 depobj->path, vername, refobj->path); 4511 return (-1); 4512 } 4513 4514 static int 4515 rtld_verify_object_versions(Obj_Entry *obj) 4516 { 4517 const Elf_Verneed *vn; 4518 const Elf_Verdef *vd; 4519 const Elf_Verdaux *vda; 4520 const Elf_Vernaux *vna; 4521 const Obj_Entry *depobj; 4522 int maxvernum, vernum; 4523 4524 if (obj->ver_checked) 4525 return (0); 4526 obj->ver_checked = true; 4527 4528 maxvernum = 0; 4529 /* 4530 * Walk over defined and required version records and figure out 4531 * max index used by any of them. Do very basic sanity checking 4532 * while there. 4533 */ 4534 vn = obj->verneed; 4535 while (vn != NULL) { 4536 if (vn->vn_version != VER_NEED_CURRENT) { 4537 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 4538 obj->path, vn->vn_version); 4539 return (-1); 4540 } 4541 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4542 for (;;) { 4543 vernum = VER_NEED_IDX(vna->vna_other); 4544 if (vernum > maxvernum) 4545 maxvernum = vernum; 4546 if (vna->vna_next == 0) 4547 break; 4548 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4549 } 4550 if (vn->vn_next == 0) 4551 break; 4552 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4553 } 4554 4555 vd = obj->verdef; 4556 while (vd != NULL) { 4557 if (vd->vd_version != VER_DEF_CURRENT) { 4558 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4559 obj->path, vd->vd_version); 4560 return (-1); 4561 } 4562 vernum = VER_DEF_IDX(vd->vd_ndx); 4563 if (vernum > maxvernum) 4564 maxvernum = vernum; 4565 if (vd->vd_next == 0) 4566 break; 4567 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4568 } 4569 4570 if (maxvernum == 0) 4571 return (0); 4572 4573 /* 4574 * Store version information in array indexable by version index. 4575 * Verify that object version requirements are satisfied along the 4576 * way. 4577 */ 4578 obj->vernum = maxvernum + 1; 4579 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 4580 4581 vd = obj->verdef; 4582 while (vd != NULL) { 4583 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 4584 vernum = VER_DEF_IDX(vd->vd_ndx); 4585 assert(vernum <= maxvernum); 4586 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 4587 obj->vertab[vernum].hash = vd->vd_hash; 4588 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 4589 obj->vertab[vernum].file = NULL; 4590 obj->vertab[vernum].flags = 0; 4591 } 4592 if (vd->vd_next == 0) 4593 break; 4594 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4595 } 4596 4597 vn = obj->verneed; 4598 while (vn != NULL) { 4599 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 4600 if (depobj == NULL) 4601 return (-1); 4602 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4603 for (;;) { 4604 if (check_object_provided_version(obj, depobj, vna)) 4605 return (-1); 4606 vernum = VER_NEED_IDX(vna->vna_other); 4607 assert(vernum <= maxvernum); 4608 obj->vertab[vernum].hash = vna->vna_hash; 4609 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 4610 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 4611 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 4612 VER_INFO_HIDDEN : 0; 4613 if (vna->vna_next == 0) 4614 break; 4615 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4616 } 4617 if (vn->vn_next == 0) 4618 break; 4619 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4620 } 4621 return 0; 4622 } 4623 4624 static int 4625 rtld_verify_versions(const Objlist *objlist) 4626 { 4627 Objlist_Entry *entry; 4628 int rc; 4629 4630 rc = 0; 4631 STAILQ_FOREACH(entry, objlist, link) { 4632 /* 4633 * Skip dummy objects or objects that have their version requirements 4634 * already checked. 4635 */ 4636 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 4637 continue; 4638 if (rtld_verify_object_versions(entry->obj) == -1) { 4639 rc = -1; 4640 if (ld_tracing == NULL) 4641 break; 4642 } 4643 } 4644 if (rc == 0 || ld_tracing != NULL) 4645 rc = rtld_verify_object_versions(&obj_rtld); 4646 return rc; 4647 } 4648 4649 const Ver_Entry * 4650 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 4651 { 4652 Elf_Versym vernum; 4653 4654 if (obj->vertab) { 4655 vernum = VER_NDX(obj->versyms[symnum]); 4656 if (vernum >= obj->vernum) { 4657 _rtld_error("%s: symbol %s has wrong verneed value %d", 4658 obj->path, obj->strtab + symnum, vernum); 4659 } else if (obj->vertab[vernum].hash != 0) { 4660 return &obj->vertab[vernum]; 4661 } 4662 } 4663 return NULL; 4664 } 4665 4666 int 4667 _rtld_get_stack_prot(void) 4668 { 4669 4670 return (stack_prot); 4671 } 4672 4673 static void 4674 map_stacks_exec(RtldLockState *lockstate) 4675 { 4676 return; 4677 /* 4678 * Stack protection must be implemented in the kernel before the dynamic 4679 * linker can handle PT_GNU_STACK sections. 4680 * The following is the FreeBSD implementation of map_stacks_exec() 4681 * void (*thr_map_stacks_exec)(void); 4682 * 4683 * if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 4684 * return; 4685 * thr_map_stacks_exec = (void (*)(void))(uintptr_t) 4686 * get_program_var_addr("__pthread_map_stacks_exec", lockstate); 4687 * if (thr_map_stacks_exec != NULL) { 4688 * stack_prot |= PROT_EXEC; 4689 * thr_map_stacks_exec(); 4690 * } 4691 */ 4692 } 4693 4694 void 4695 symlook_init(SymLook *dst, const char *name) 4696 { 4697 4698 bzero(dst, sizeof(*dst)); 4699 dst->name = name; 4700 dst->hash = elf_hash(name); 4701 dst->hash_gnu = gnu_hash(name); 4702 } 4703 4704 static void 4705 symlook_init_from_req(SymLook *dst, const SymLook *src) 4706 { 4707 4708 dst->name = src->name; 4709 dst->hash = src->hash; 4710 dst->hash_gnu = src->hash_gnu; 4711 dst->ventry = src->ventry; 4712 dst->flags = src->flags; 4713 dst->defobj_out = NULL; 4714 dst->sym_out = NULL; 4715 dst->lockstate = src->lockstate; 4716 } 4717 4718 #ifdef ENABLE_OSRELDATE 4719 /* 4720 * Overrides for libc_pic-provided functions. 4721 */ 4722 4723 int 4724 __getosreldate(void) 4725 { 4726 size_t len; 4727 int oid[2]; 4728 int error, osrel; 4729 4730 if (osreldate != 0) 4731 return (osreldate); 4732 4733 oid[0] = CTL_KERN; 4734 oid[1] = KERN_OSRELDATE; 4735 osrel = 0; 4736 len = sizeof(osrel); 4737 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 4738 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 4739 osreldate = osrel; 4740 return (osreldate); 4741 } 4742 #endif 4743 4744 /* 4745 * No unresolved symbols for rtld. 4746 */ 4747 void 4748 __pthread_cxa_finalize(struct dl_phdr_info *a) 4749 { 4750 } 4751 4752 const char * 4753 rtld_strerror(int errnum) 4754 { 4755 4756 if (errnum < 0 || errnum >= sys_nerr) 4757 return ("Unknown error"); 4758 return (sys_errlist[errnum]); 4759 } 4760