rtld.c revision 199829
1/*- 2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra. 3 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>. 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 * 26 * $FreeBSD: head/libexec/rtld-elf/rtld.c 199829 2009-11-26 13:57:20Z kib $ 27 */ 28 29/* 30 * Dynamic linker for ELF. 31 * 32 * John Polstra <jdp@polstra.com>. 33 */ 34 35#ifndef __GNUC__ 36#error "GCC is needed to compile this file" 37#endif 38 39#include <sys/param.h> 40#include <sys/mount.h> 41#include <sys/mman.h> 42#include <sys/stat.h> 43#include <sys/uio.h> 44#include <sys/utsname.h> 45#include <sys/ktrace.h> 46 47#include <dlfcn.h> 48#include <err.h> 49#include <errno.h> 50#include <fcntl.h> 51#include <stdarg.h> 52#include <stdio.h> 53#include <stdlib.h> 54#include <string.h> 55#include <unistd.h> 56 57#include "debug.h" 58#include "rtld.h" 59#include "libmap.h" 60#include "rtld_tls.h" 61 62#ifndef COMPAT_32BIT 63#define PATH_RTLD "/libexec/ld-elf.so.1" 64#else 65#define PATH_RTLD "/libexec/ld-elf32.so.1" 66#endif 67 68/* Types. */ 69typedef void (*func_ptr_type)(); 70typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 71 72/* 73 * This structure provides a reentrant way to keep a list of objects and 74 * check which ones have already been processed in some way. 75 */ 76typedef struct Struct_DoneList { 77 const Obj_Entry **objs; /* Array of object pointers */ 78 unsigned int num_alloc; /* Allocated size of the array */ 79 unsigned int num_used; /* Number of array slots used */ 80} DoneList; 81 82/* 83 * Function declarations. 84 */ 85static const char *basename(const char *); 86static void die(void) __dead2; 87static void digest_dynamic(Obj_Entry *, int); 88static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 89static Obj_Entry *dlcheck(void *); 90static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 91static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 92static bool donelist_check(DoneList *, const Obj_Entry *); 93static void errmsg_restore(char *); 94static char *errmsg_save(void); 95static void *fill_search_info(const char *, size_t, void *); 96static char *find_library(const char *, const Obj_Entry *); 97static const char *gethints(void); 98static void init_dag(Obj_Entry *); 99static void init_dag1(Obj_Entry *, Obj_Entry *, DoneList *); 100static void init_rtld(caddr_t); 101static void initlist_add_neededs(Needed_Entry *, Objlist *); 102static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *); 103static bool is_exported(const Elf_Sym *); 104static void linkmap_add(Obj_Entry *); 105static void linkmap_delete(Obj_Entry *); 106static int load_needed_objects(Obj_Entry *, int); 107static int load_preload_objects(void); 108static Obj_Entry *load_object(const char *, const Obj_Entry *, int); 109static Obj_Entry *obj_from_addr(const void *); 110static void objlist_call_fini(Objlist *, bool, int *); 111static void objlist_call_init(Objlist *, int *); 112static void objlist_clear(Objlist *); 113static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 114static void objlist_init(Objlist *); 115static void objlist_push_head(Objlist *, Obj_Entry *); 116static void objlist_push_tail(Objlist *, Obj_Entry *); 117static void objlist_remove(Objlist *, Obj_Entry *); 118static void *path_enumerate(const char *, path_enum_proc, void *); 119static int relocate_objects(Obj_Entry *, bool, Obj_Entry *); 120static int rtld_dirname(const char *, char *); 121static int rtld_dirname_abs(const char *, char *); 122static void rtld_exit(void); 123static char *search_library_path(const char *, const char *); 124static const void **get_program_var_addr(const char *); 125static void set_program_var(const char *, const void *); 126static const Elf_Sym *symlook_default(const char *, unsigned long, 127 const Obj_Entry *, const Obj_Entry **, const Ver_Entry *, int); 128static const Elf_Sym *symlook_list(const char *, unsigned long, const Objlist *, 129 const Obj_Entry **, const Ver_Entry *, int, DoneList *); 130static const Elf_Sym *symlook_needed(const char *, unsigned long, 131 const Needed_Entry *, const Obj_Entry **, const Ver_Entry *, 132 int, DoneList *); 133static void trace_loaded_objects(Obj_Entry *); 134static void unlink_object(Obj_Entry *); 135static void unload_object(Obj_Entry *); 136static void unref_dag(Obj_Entry *); 137static void ref_dag(Obj_Entry *); 138static int origin_subst_one(char **, const char *, const char *, 139 const char *, char *); 140static char *origin_subst(const char *, const char *); 141static int rtld_verify_versions(const Objlist *); 142static int rtld_verify_object_versions(Obj_Entry *); 143static void object_add_name(Obj_Entry *, const char *); 144static int object_match_name(const Obj_Entry *, const char *); 145static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 146 147void r_debug_state(struct r_debug *, struct link_map *); 148 149/* 150 * Data declarations. 151 */ 152static char *error_message; /* Message for dlerror(), or NULL */ 153struct r_debug r_debug; /* for GDB; */ 154static bool libmap_disable; /* Disable libmap */ 155static char *libmap_override; /* Maps to use in addition to libmap.conf */ 156static bool trust; /* False for setuid and setgid programs */ 157static bool dangerous_ld_env; /* True if environment variables have been 158 used to affect the libraries loaded */ 159static char *ld_bind_now; /* Environment variable for immediate binding */ 160static char *ld_debug; /* Environment variable for debugging */ 161static char *ld_library_path; /* Environment variable for search path */ 162static char *ld_preload; /* Environment variable for libraries to 163 load first */ 164static char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 165static char *ld_tracing; /* Called from ldd to print libs */ 166static char *ld_utrace; /* Use utrace() to log events. */ 167static Obj_Entry *obj_list; /* Head of linked list of shared objects */ 168static Obj_Entry **obj_tail; /* Link field of last object in list */ 169static Obj_Entry *obj_main; /* The main program shared object */ 170static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 171static unsigned int obj_count; /* Number of objects in obj_list */ 172static unsigned int obj_loads; /* Number of objects in obj_list */ 173 174static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 175 STAILQ_HEAD_INITIALIZER(list_global); 176static Objlist list_main = /* Objects loaded at program startup */ 177 STAILQ_HEAD_INITIALIZER(list_main); 178static Objlist list_fini = /* Objects needing fini() calls */ 179 STAILQ_HEAD_INITIALIZER(list_fini); 180 181static Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 182 183#define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 184 185extern Elf_Dyn _DYNAMIC; 186#pragma weak _DYNAMIC 187#ifndef RTLD_IS_DYNAMIC 188#define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL) 189#endif 190 191/* 192 * These are the functions the dynamic linker exports to application 193 * programs. They are the only symbols the dynamic linker is willing 194 * to export from itself. 195 */ 196static func_ptr_type exports[] = { 197 (func_ptr_type) &_rtld_error, 198 (func_ptr_type) &dlclose, 199 (func_ptr_type) &dlerror, 200 (func_ptr_type) &dlopen, 201 (func_ptr_type) &dlsym, 202 (func_ptr_type) &dlfunc, 203 (func_ptr_type) &dlvsym, 204 (func_ptr_type) &dladdr, 205 (func_ptr_type) &dllockinit, 206 (func_ptr_type) &dlinfo, 207 (func_ptr_type) &_rtld_thread_init, 208#ifdef __i386__ 209 (func_ptr_type) &___tls_get_addr, 210#endif 211 (func_ptr_type) &__tls_get_addr, 212 (func_ptr_type) &_rtld_allocate_tls, 213 (func_ptr_type) &_rtld_free_tls, 214 (func_ptr_type) &dl_iterate_phdr, 215 (func_ptr_type) &_rtld_atfork_pre, 216 (func_ptr_type) &_rtld_atfork_post, 217 NULL 218}; 219 220/* 221 * Global declarations normally provided by crt1. The dynamic linker is 222 * not built with crt1, so we have to provide them ourselves. 223 */ 224char *__progname; 225char **environ; 226 227/* 228 * Globals to control TLS allocation. 229 */ 230size_t tls_last_offset; /* Static TLS offset of last module */ 231size_t tls_last_size; /* Static TLS size of last module */ 232size_t tls_static_space; /* Static TLS space allocated */ 233int tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 234int tls_max_index = 1; /* Largest module index allocated */ 235 236/* 237 * Fill in a DoneList with an allocation large enough to hold all of 238 * the currently-loaded objects. Keep this as a macro since it calls 239 * alloca and we want that to occur within the scope of the caller. 240 */ 241#define donelist_init(dlp) \ 242 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 243 assert((dlp)->objs != NULL), \ 244 (dlp)->num_alloc = obj_count, \ 245 (dlp)->num_used = 0) 246 247#define UTRACE_DLOPEN_START 1 248#define UTRACE_DLOPEN_STOP 2 249#define UTRACE_DLCLOSE_START 3 250#define UTRACE_DLCLOSE_STOP 4 251#define UTRACE_LOAD_OBJECT 5 252#define UTRACE_UNLOAD_OBJECT 6 253#define UTRACE_ADD_RUNDEP 7 254#define UTRACE_PRELOAD_FINISHED 8 255#define UTRACE_INIT_CALL 9 256#define UTRACE_FINI_CALL 10 257 258struct utrace_rtld { 259 char sig[4]; /* 'RTLD' */ 260 int event; 261 void *handle; 262 void *mapbase; /* Used for 'parent' and 'init/fini' */ 263 size_t mapsize; 264 int refcnt; /* Used for 'mode' */ 265 char name[MAXPATHLEN]; 266}; 267 268#define LD_UTRACE(e, h, mb, ms, r, n) do { \ 269 if (ld_utrace != NULL) \ 270 ld_utrace_log(e, h, mb, ms, r, n); \ 271} while (0) 272 273static void 274ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 275 int refcnt, const char *name) 276{ 277 struct utrace_rtld ut; 278 279 ut.sig[0] = 'R'; 280 ut.sig[1] = 'T'; 281 ut.sig[2] = 'L'; 282 ut.sig[3] = 'D'; 283 ut.event = event; 284 ut.handle = handle; 285 ut.mapbase = mapbase; 286 ut.mapsize = mapsize; 287 ut.refcnt = refcnt; 288 bzero(ut.name, sizeof(ut.name)); 289 if (name) 290 strlcpy(ut.name, name, sizeof(ut.name)); 291 utrace(&ut, sizeof(ut)); 292} 293 294/* 295 * Main entry point for dynamic linking. The first argument is the 296 * stack pointer. The stack is expected to be laid out as described 297 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 298 * Specifically, the stack pointer points to a word containing 299 * ARGC. Following that in the stack is a null-terminated sequence 300 * of pointers to argument strings. Then comes a null-terminated 301 * sequence of pointers to environment strings. Finally, there is a 302 * sequence of "auxiliary vector" entries. 303 * 304 * The second argument points to a place to store the dynamic linker's 305 * exit procedure pointer and the third to a place to store the main 306 * program's object. 307 * 308 * The return value is the main program's entry point. 309 */ 310func_ptr_type 311_rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 312{ 313 Elf_Auxinfo *aux_info[AT_COUNT]; 314 int i; 315 int argc; 316 char **argv; 317 char **env; 318 Elf_Auxinfo *aux; 319 Elf_Auxinfo *auxp; 320 const char *argv0; 321 Objlist_Entry *entry; 322 Obj_Entry *obj; 323 Obj_Entry **preload_tail; 324 Objlist initlist; 325 int lockstate; 326 327 /* 328 * On entry, the dynamic linker itself has not been relocated yet. 329 * Be very careful not to reference any global data until after 330 * init_rtld has returned. It is OK to reference file-scope statics 331 * and string constants, and to call static and global functions. 332 */ 333 334 /* Find the auxiliary vector on the stack. */ 335 argc = *sp++; 336 argv = (char **) sp; 337 sp += argc + 1; /* Skip over arguments and NULL terminator */ 338 env = (char **) sp; 339 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 340 ; 341 aux = (Elf_Auxinfo *) sp; 342 343 /* Digest the auxiliary vector. */ 344 for (i = 0; i < AT_COUNT; i++) 345 aux_info[i] = NULL; 346 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 347 if (auxp->a_type < AT_COUNT) 348 aux_info[auxp->a_type] = auxp; 349 } 350 351 /* Initialize and relocate ourselves. */ 352 assert(aux_info[AT_BASE] != NULL); 353 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 354 355 __progname = obj_rtld.path; 356 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 357 environ = env; 358 359 trust = !issetugid(); 360 361 ld_bind_now = getenv(LD_ "BIND_NOW"); 362 /* 363 * If the process is tainted, then we un-set the dangerous environment 364 * variables. The process will be marked as tainted until setuid(2) 365 * is called. If any child process calls setuid(2) we do not want any 366 * future processes to honor the potentially un-safe variables. 367 */ 368 if (!trust) { 369 unsetenv(LD_ "PRELOAD"); 370 unsetenv(LD_ "LIBMAP"); 371 unsetenv(LD_ "LIBRARY_PATH"); 372 unsetenv(LD_ "LIBMAP_DISABLE"); 373 unsetenv(LD_ "DEBUG"); 374 unsetenv(LD_ "ELF_HINTS_PATH"); 375 } 376 ld_debug = getenv(LD_ "DEBUG"); 377 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL; 378 libmap_override = getenv(LD_ "LIBMAP"); 379 ld_library_path = getenv(LD_ "LIBRARY_PATH"); 380 ld_preload = getenv(LD_ "PRELOAD"); 381 ld_elf_hints_path = getenv(LD_ "ELF_HINTS_PATH"); 382 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 383 (ld_library_path != NULL) || (ld_preload != NULL) || 384 (ld_elf_hints_path != NULL); 385 ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS"); 386 ld_utrace = getenv(LD_ "UTRACE"); 387 388 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 389 ld_elf_hints_path = _PATH_ELF_HINTS; 390 391 if (ld_debug != NULL && *ld_debug != '\0') 392 debug = 1; 393 dbg("%s is initialized, base address = %p", __progname, 394 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 395 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 396 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 397 398 /* 399 * Load the main program, or process its program header if it is 400 * already loaded. 401 */ 402 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */ 403 int fd = aux_info[AT_EXECFD]->a_un.a_val; 404 dbg("loading main program"); 405 obj_main = map_object(fd, argv0, NULL); 406 close(fd); 407 if (obj_main == NULL) 408 die(); 409 } else { /* Main program already loaded. */ 410 const Elf_Phdr *phdr; 411 int phnum; 412 caddr_t entry; 413 414 dbg("processing main program's program header"); 415 assert(aux_info[AT_PHDR] != NULL); 416 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 417 assert(aux_info[AT_PHNUM] != NULL); 418 phnum = aux_info[AT_PHNUM]->a_un.a_val; 419 assert(aux_info[AT_PHENT] != NULL); 420 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 421 assert(aux_info[AT_ENTRY] != NULL); 422 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 423 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL) 424 die(); 425 } 426 427 if (aux_info[AT_EXECPATH] != 0) { 428 char *kexecpath; 429 char buf[MAXPATHLEN]; 430 431 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 432 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 433 if (kexecpath[0] == '/') 434 obj_main->path = kexecpath; 435 else if (getcwd(buf, sizeof(buf)) == NULL || 436 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 437 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 438 obj_main->path = xstrdup(argv0); 439 else 440 obj_main->path = xstrdup(buf); 441 } else { 442 dbg("No AT_EXECPATH"); 443 obj_main->path = xstrdup(argv0); 444 } 445 dbg("obj_main path %s", obj_main->path); 446 obj_main->mainprog = true; 447 448 /* 449 * Get the actual dynamic linker pathname from the executable if 450 * possible. (It should always be possible.) That ensures that 451 * gdb will find the right dynamic linker even if a non-standard 452 * one is being used. 453 */ 454 if (obj_main->interp != NULL && 455 strcmp(obj_main->interp, obj_rtld.path) != 0) { 456 free(obj_rtld.path); 457 obj_rtld.path = xstrdup(obj_main->interp); 458 __progname = obj_rtld.path; 459 } 460 461 digest_dynamic(obj_main, 0); 462 463 linkmap_add(obj_main); 464 linkmap_add(&obj_rtld); 465 466 /* Link the main program into the list of objects. */ 467 *obj_tail = obj_main; 468 obj_tail = &obj_main->next; 469 obj_count++; 470 obj_loads++; 471 /* Make sure we don't call the main program's init and fini functions. */ 472 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 473 474 /* Initialize a fake symbol for resolving undefined weak references. */ 475 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 476 sym_zero.st_shndx = SHN_UNDEF; 477 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 478 479 if (!libmap_disable) 480 libmap_disable = (bool)lm_init(libmap_override); 481 482 dbg("loading LD_PRELOAD libraries"); 483 if (load_preload_objects() == -1) 484 die(); 485 preload_tail = obj_tail; 486 487 dbg("loading needed objects"); 488 if (load_needed_objects(obj_main, 0) == -1) 489 die(); 490 491 /* Make a list of all objects loaded at startup. */ 492 for (obj = obj_list; obj != NULL; obj = obj->next) { 493 objlist_push_tail(&list_main, obj); 494 obj->refcount++; 495 } 496 497 dbg("checking for required versions"); 498 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 499 die(); 500 501 if (ld_tracing) { /* We're done */ 502 trace_loaded_objects(obj_main); 503 exit(0); 504 } 505 506 if (getenv(LD_ "DUMP_REL_PRE") != NULL) { 507 dump_relocations(obj_main); 508 exit (0); 509 } 510 511 /* setup TLS for main thread */ 512 dbg("initializing initial thread local storage"); 513 STAILQ_FOREACH(entry, &list_main, link) { 514 /* 515 * Allocate all the initial objects out of the static TLS 516 * block even if they didn't ask for it. 517 */ 518 allocate_tls_offset(entry->obj); 519 } 520 allocate_initial_tls(obj_list); 521 522 if (relocate_objects(obj_main, 523 ld_bind_now != NULL && *ld_bind_now != '\0', &obj_rtld) == -1) 524 die(); 525 526 dbg("doing copy relocations"); 527 if (do_copy_relocations(obj_main) == -1) 528 die(); 529 530 if (getenv(LD_ "DUMP_REL_POST") != NULL) { 531 dump_relocations(obj_main); 532 exit (0); 533 } 534 535 dbg("initializing key program variables"); 536 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 537 set_program_var("environ", env); 538 539 dbg("initializing thread locks"); 540 lockdflt_init(); 541 542 /* Make a list of init functions to call. */ 543 objlist_init(&initlist); 544 initlist_add_objects(obj_list, preload_tail, &initlist); 545 546 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 547 548 lockstate = wlock_acquire(rtld_bind_lock); 549 objlist_call_init(&initlist, &lockstate); 550 objlist_clear(&initlist); 551 wlock_release(rtld_bind_lock, lockstate); 552 553 dbg("transferring control to program entry point = %p", obj_main->entry); 554 555 /* Return the exit procedure and the program entry point. */ 556 *exit_proc = rtld_exit; 557 *objp = obj_main; 558 return (func_ptr_type) obj_main->entry; 559} 560 561Elf_Addr 562_rtld_bind(Obj_Entry *obj, Elf_Size reloff) 563{ 564 const Elf_Rel *rel; 565 const Elf_Sym *def; 566 const Obj_Entry *defobj; 567 Elf_Addr *where; 568 Elf_Addr target; 569 int lockstate; 570 571 lockstate = rlock_acquire(rtld_bind_lock); 572 if (obj->pltrel) 573 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 574 else 575 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 576 577 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 578 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL); 579 if (def == NULL) 580 die(); 581 582 target = (Elf_Addr)(defobj->relocbase + def->st_value); 583 584 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 585 defobj->strtab + def->st_name, basename(obj->path), 586 (void *)target, basename(defobj->path)); 587 588 /* 589 * Write the new contents for the jmpslot. Note that depending on 590 * architecture, the value which we need to return back to the 591 * lazy binding trampoline may or may not be the target 592 * address. The value returned from reloc_jmpslot() is the value 593 * that the trampoline needs. 594 */ 595 target = reloc_jmpslot(where, target, defobj, obj, rel); 596 rlock_release(rtld_bind_lock, lockstate); 597 return target; 598} 599 600/* 601 * Error reporting function. Use it like printf. If formats the message 602 * into a buffer, and sets things up so that the next call to dlerror() 603 * will return the message. 604 */ 605void 606_rtld_error(const char *fmt, ...) 607{ 608 static char buf[512]; 609 va_list ap; 610 611 va_start(ap, fmt); 612 vsnprintf(buf, sizeof buf, fmt, ap); 613 error_message = buf; 614 va_end(ap); 615} 616 617/* 618 * Return a dynamically-allocated copy of the current error message, if any. 619 */ 620static char * 621errmsg_save(void) 622{ 623 return error_message == NULL ? NULL : xstrdup(error_message); 624} 625 626/* 627 * Restore the current error message from a copy which was previously saved 628 * by errmsg_save(). The copy is freed. 629 */ 630static void 631errmsg_restore(char *saved_msg) 632{ 633 if (saved_msg == NULL) 634 error_message = NULL; 635 else { 636 _rtld_error("%s", saved_msg); 637 free(saved_msg); 638 } 639} 640 641static const char * 642basename(const char *name) 643{ 644 const char *p = strrchr(name, '/'); 645 return p != NULL ? p + 1 : name; 646} 647 648static struct utsname uts; 649 650static int 651origin_subst_one(char **res, const char *real, const char *kw, const char *subst, 652 char *may_free) 653{ 654 const char *p, *p1; 655 char *res1; 656 int subst_len; 657 int kw_len; 658 659 res1 = *res = NULL; 660 p = real; 661 subst_len = kw_len = 0; 662 for (;;) { 663 p1 = strstr(p, kw); 664 if (p1 != NULL) { 665 if (subst_len == 0) { 666 subst_len = strlen(subst); 667 kw_len = strlen(kw); 668 } 669 if (*res == NULL) { 670 *res = xmalloc(PATH_MAX); 671 res1 = *res; 672 } 673 if ((res1 - *res) + subst_len + (p1 - p) >= PATH_MAX) { 674 _rtld_error("Substitution of %s in %s cannot be performed", 675 kw, real); 676 if (may_free != NULL) 677 free(may_free); 678 free(res); 679 return (false); 680 } 681 memcpy(res1, p, p1 - p); 682 res1 += p1 - p; 683 memcpy(res1, subst, subst_len); 684 res1 += subst_len; 685 p = p1 + kw_len; 686 } else { 687 if (*res == NULL) { 688 if (may_free != NULL) 689 *res = may_free; 690 else 691 *res = xstrdup(real); 692 return (true); 693 } 694 *res1 = '\0'; 695 if (may_free != NULL) 696 free(may_free); 697 if (strlcat(res1, p, PATH_MAX - (res1 - *res)) >= PATH_MAX) { 698 free(res); 699 return (false); 700 } 701 return (true); 702 } 703 } 704} 705 706static char * 707origin_subst(const char *real, const char *origin_path) 708{ 709 char *res1, *res2, *res3, *res4; 710 711 if (uts.sysname[0] == '\0') { 712 if (uname(&uts) != 0) { 713 _rtld_error("utsname failed: %d", errno); 714 return (NULL); 715 } 716 } 717 if (!origin_subst_one(&res1, real, "$ORIGIN", origin_path, NULL) || 718 !origin_subst_one(&res2, res1, "$OSNAME", uts.sysname, res1) || 719 !origin_subst_one(&res3, res2, "$OSREL", uts.release, res2) || 720 !origin_subst_one(&res4, res3, "$PLATFORM", uts.machine, res3)) 721 return (NULL); 722 return (res4); 723} 724 725static void 726die(void) 727{ 728 const char *msg = dlerror(); 729 730 if (msg == NULL) 731 msg = "Fatal error"; 732 errx(1, "%s", msg); 733} 734 735/* 736 * Process a shared object's DYNAMIC section, and save the important 737 * information in its Obj_Entry structure. 738 */ 739static void 740digest_dynamic(Obj_Entry *obj, int early) 741{ 742 const Elf_Dyn *dynp; 743 Needed_Entry **needed_tail = &obj->needed; 744 const Elf_Dyn *dyn_rpath = NULL; 745 const Elf_Dyn *dyn_soname = NULL; 746 int plttype = DT_REL; 747 748 obj->bind_now = false; 749 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 750 switch (dynp->d_tag) { 751 752 case DT_REL: 753 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 754 break; 755 756 case DT_RELSZ: 757 obj->relsize = dynp->d_un.d_val; 758 break; 759 760 case DT_RELENT: 761 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 762 break; 763 764 case DT_JMPREL: 765 obj->pltrel = (const Elf_Rel *) 766 (obj->relocbase + dynp->d_un.d_ptr); 767 break; 768 769 case DT_PLTRELSZ: 770 obj->pltrelsize = dynp->d_un.d_val; 771 break; 772 773 case DT_RELA: 774 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 775 break; 776 777 case DT_RELASZ: 778 obj->relasize = dynp->d_un.d_val; 779 break; 780 781 case DT_RELAENT: 782 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 783 break; 784 785 case DT_PLTREL: 786 plttype = dynp->d_un.d_val; 787 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 788 break; 789 790 case DT_SYMTAB: 791 obj->symtab = (const Elf_Sym *) 792 (obj->relocbase + dynp->d_un.d_ptr); 793 break; 794 795 case DT_SYMENT: 796 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 797 break; 798 799 case DT_STRTAB: 800 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 801 break; 802 803 case DT_STRSZ: 804 obj->strsize = dynp->d_un.d_val; 805 break; 806 807 case DT_VERNEED: 808 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 809 dynp->d_un.d_val); 810 break; 811 812 case DT_VERNEEDNUM: 813 obj->verneednum = dynp->d_un.d_val; 814 break; 815 816 case DT_VERDEF: 817 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 818 dynp->d_un.d_val); 819 break; 820 821 case DT_VERDEFNUM: 822 obj->verdefnum = dynp->d_un.d_val; 823 break; 824 825 case DT_VERSYM: 826 obj->versyms = (const Elf_Versym *)(obj->relocbase + 827 dynp->d_un.d_val); 828 break; 829 830 case DT_HASH: 831 { 832 const Elf_Hashelt *hashtab = (const Elf_Hashelt *) 833 (obj->relocbase + dynp->d_un.d_ptr); 834 obj->nbuckets = hashtab[0]; 835 obj->nchains = hashtab[1]; 836 obj->buckets = hashtab + 2; 837 obj->chains = obj->buckets + obj->nbuckets; 838 } 839 break; 840 841 case DT_NEEDED: 842 if (!obj->rtld) { 843 Needed_Entry *nep = NEW(Needed_Entry); 844 nep->name = dynp->d_un.d_val; 845 nep->obj = NULL; 846 nep->next = NULL; 847 848 *needed_tail = nep; 849 needed_tail = &nep->next; 850 } 851 break; 852 853 case DT_PLTGOT: 854 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 855 break; 856 857 case DT_TEXTREL: 858 obj->textrel = true; 859 break; 860 861 case DT_SYMBOLIC: 862 obj->symbolic = true; 863 break; 864 865 case DT_RPATH: 866 case DT_RUNPATH: /* XXX: process separately */ 867 /* 868 * We have to wait until later to process this, because we 869 * might not have gotten the address of the string table yet. 870 */ 871 dyn_rpath = dynp; 872 break; 873 874 case DT_SONAME: 875 dyn_soname = dynp; 876 break; 877 878 case DT_INIT: 879 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 880 break; 881 882 case DT_FINI: 883 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 884 break; 885 886 /* 887 * Don't process DT_DEBUG on MIPS as the dynamic section 888 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 889 */ 890 891#ifndef __mips__ 892 case DT_DEBUG: 893 /* XXX - not implemented yet */ 894 if (!early) 895 dbg("Filling in DT_DEBUG entry"); 896 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 897 break; 898#endif 899 900 case DT_FLAGS: 901 if ((dynp->d_un.d_val & DF_ORIGIN) && trust) 902 obj->z_origin = true; 903 if (dynp->d_un.d_val & DF_SYMBOLIC) 904 obj->symbolic = true; 905 if (dynp->d_un.d_val & DF_TEXTREL) 906 obj->textrel = true; 907 if (dynp->d_un.d_val & DF_BIND_NOW) 908 obj->bind_now = true; 909 if (dynp->d_un.d_val & DF_STATIC_TLS) 910 ; 911 break; 912#ifdef __mips__ 913 case DT_MIPS_LOCAL_GOTNO: 914 obj->local_gotno = dynp->d_un.d_val; 915 break; 916 917 case DT_MIPS_SYMTABNO: 918 obj->symtabno = dynp->d_un.d_val; 919 break; 920 921 case DT_MIPS_GOTSYM: 922 obj->gotsym = dynp->d_un.d_val; 923 break; 924 925 case DT_MIPS_RLD_MAP: 926#ifdef notyet 927 if (!early) 928 dbg("Filling in DT_DEBUG entry"); 929 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 930#endif 931 break; 932#endif 933 934 case DT_FLAGS_1: 935 if (dynp->d_un.d_val & DF_1_NOOPEN) 936 obj->z_noopen = true; 937 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust) 938 obj->z_origin = true; 939 if (dynp->d_un.d_val & DF_1_GLOBAL) 940 /* XXX */; 941 if (dynp->d_un.d_val & DF_1_BIND_NOW) 942 obj->bind_now = true; 943 if (dynp->d_un.d_val & DF_1_NODELETE) 944 obj->z_nodelete = true; 945 break; 946 947 default: 948 if (!early) { 949 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 950 (long)dynp->d_tag); 951 } 952 break; 953 } 954 } 955 956 obj->traced = false; 957 958 if (plttype == DT_RELA) { 959 obj->pltrela = (const Elf_Rela *) obj->pltrel; 960 obj->pltrel = NULL; 961 obj->pltrelasize = obj->pltrelsize; 962 obj->pltrelsize = 0; 963 } 964 965 if (obj->z_origin && obj->origin_path == NULL) { 966 obj->origin_path = xmalloc(PATH_MAX); 967 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1) 968 die(); 969 } 970 971 if (dyn_rpath != NULL) { 972 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 973 if (obj->z_origin) 974 obj->rpath = origin_subst(obj->rpath, obj->origin_path); 975 } 976 977 if (dyn_soname != NULL) 978 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 979} 980 981/* 982 * Process a shared object's program header. This is used only for the 983 * main program, when the kernel has already loaded the main program 984 * into memory before calling the dynamic linker. It creates and 985 * returns an Obj_Entry structure. 986 */ 987static Obj_Entry * 988digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 989{ 990 Obj_Entry *obj; 991 const Elf_Phdr *phlimit = phdr + phnum; 992 const Elf_Phdr *ph; 993 int nsegs = 0; 994 995 obj = obj_new(); 996 for (ph = phdr; ph < phlimit; ph++) { 997 if (ph->p_type != PT_PHDR) 998 continue; 999 1000 obj->phdr = phdr; 1001 obj->phsize = ph->p_memsz; 1002 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1003 break; 1004 } 1005 1006 for (ph = phdr; ph < phlimit; ph++) { 1007 switch (ph->p_type) { 1008 1009 case PT_INTERP: 1010 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1011 break; 1012 1013 case PT_LOAD: 1014 if (nsegs == 0) { /* First load segment */ 1015 obj->vaddrbase = trunc_page(ph->p_vaddr); 1016 obj->mapbase = obj->vaddrbase + obj->relocbase; 1017 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1018 obj->vaddrbase; 1019 } else { /* Last load segment */ 1020 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1021 obj->vaddrbase; 1022 } 1023 nsegs++; 1024 break; 1025 1026 case PT_DYNAMIC: 1027 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1028 break; 1029 1030 case PT_TLS: 1031 obj->tlsindex = 1; 1032 obj->tlssize = ph->p_memsz; 1033 obj->tlsalign = ph->p_align; 1034 obj->tlsinitsize = ph->p_filesz; 1035 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1036 break; 1037 } 1038 } 1039 if (nsegs < 1) { 1040 _rtld_error("%s: too few PT_LOAD segments", path); 1041 return NULL; 1042 } 1043 1044 obj->entry = entry; 1045 return obj; 1046} 1047 1048static Obj_Entry * 1049dlcheck(void *handle) 1050{ 1051 Obj_Entry *obj; 1052 1053 for (obj = obj_list; obj != NULL; obj = obj->next) 1054 if (obj == (Obj_Entry *) handle) 1055 break; 1056 1057 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1058 _rtld_error("Invalid shared object handle %p", handle); 1059 return NULL; 1060 } 1061 return obj; 1062} 1063 1064/* 1065 * If the given object is already in the donelist, return true. Otherwise 1066 * add the object to the list and return false. 1067 */ 1068static bool 1069donelist_check(DoneList *dlp, const Obj_Entry *obj) 1070{ 1071 unsigned int i; 1072 1073 for (i = 0; i < dlp->num_used; i++) 1074 if (dlp->objs[i] == obj) 1075 return true; 1076 /* 1077 * Our donelist allocation should always be sufficient. But if 1078 * our threads locking isn't working properly, more shared objects 1079 * could have been loaded since we allocated the list. That should 1080 * never happen, but we'll handle it properly just in case it does. 1081 */ 1082 if (dlp->num_used < dlp->num_alloc) 1083 dlp->objs[dlp->num_used++] = obj; 1084 return false; 1085} 1086 1087/* 1088 * Hash function for symbol table lookup. Don't even think about changing 1089 * this. It is specified by the System V ABI. 1090 */ 1091unsigned long 1092elf_hash(const char *name) 1093{ 1094 const unsigned char *p = (const unsigned char *) name; 1095 unsigned long h = 0; 1096 unsigned long g; 1097 1098 while (*p != '\0') { 1099 h = (h << 4) + *p++; 1100 if ((g = h & 0xf0000000) != 0) 1101 h ^= g >> 24; 1102 h &= ~g; 1103 } 1104 return h; 1105} 1106 1107/* 1108 * Find the library with the given name, and return its full pathname. 1109 * The returned string is dynamically allocated. Generates an error 1110 * message and returns NULL if the library cannot be found. 1111 * 1112 * If the second argument is non-NULL, then it refers to an already- 1113 * loaded shared object, whose library search path will be searched. 1114 * 1115 * The search order is: 1116 * LD_LIBRARY_PATH 1117 * rpath in the referencing file 1118 * ldconfig hints 1119 * /lib:/usr/lib 1120 */ 1121static char * 1122find_library(const char *xname, const Obj_Entry *refobj) 1123{ 1124 char *pathname; 1125 char *name; 1126 1127 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */ 1128 if (xname[0] != '/' && !trust) { 1129 _rtld_error("Absolute pathname required for shared object \"%s\"", 1130 xname); 1131 return NULL; 1132 } 1133 if (refobj != NULL && refobj->z_origin) 1134 return origin_subst(xname, refobj->origin_path); 1135 else 1136 return xstrdup(xname); 1137 } 1138 1139 if (libmap_disable || (refobj == NULL) || 1140 (name = lm_find(refobj->path, xname)) == NULL) 1141 name = (char *)xname; 1142 1143 dbg(" Searching for \"%s\"", name); 1144 1145 if ((pathname = search_library_path(name, ld_library_path)) != NULL || 1146 (refobj != NULL && 1147 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1148 (pathname = search_library_path(name, gethints())) != NULL || 1149 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL) 1150 return pathname; 1151 1152 if(refobj != NULL && refobj->path != NULL) { 1153 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 1154 name, basename(refobj->path)); 1155 } else { 1156 _rtld_error("Shared object \"%s\" not found", name); 1157 } 1158 return NULL; 1159} 1160 1161/* 1162 * Given a symbol number in a referencing object, find the corresponding 1163 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1164 * no definition was found. Returns a pointer to the Obj_Entry of the 1165 * defining object via the reference parameter DEFOBJ_OUT. 1166 */ 1167const Elf_Sym * 1168find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1169 const Obj_Entry **defobj_out, int flags, SymCache *cache) 1170{ 1171 const Elf_Sym *ref; 1172 const Elf_Sym *def; 1173 const Obj_Entry *defobj; 1174 const Ver_Entry *ventry; 1175 const char *name; 1176 unsigned long hash; 1177 1178 /* 1179 * If we have already found this symbol, get the information from 1180 * the cache. 1181 */ 1182 if (symnum >= refobj->nchains) 1183 return NULL; /* Bad object */ 1184 if (cache != NULL && cache[symnum].sym != NULL) { 1185 *defobj_out = cache[symnum].obj; 1186 return cache[symnum].sym; 1187 } 1188 1189 ref = refobj->symtab + symnum; 1190 name = refobj->strtab + ref->st_name; 1191 defobj = NULL; 1192 1193 /* 1194 * We don't have to do a full scale lookup if the symbol is local. 1195 * We know it will bind to the instance in this load module; to 1196 * which we already have a pointer (ie ref). By not doing a lookup, 1197 * we not only improve performance, but it also avoids unresolvable 1198 * symbols when local symbols are not in the hash table. This has 1199 * been seen with the ia64 toolchain. 1200 */ 1201 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1202 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1203 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1204 symnum); 1205 } 1206 ventry = fetch_ventry(refobj, symnum); 1207 hash = elf_hash(name); 1208 def = symlook_default(name, hash, refobj, &defobj, ventry, flags); 1209 } else { 1210 def = ref; 1211 defobj = refobj; 1212 } 1213 1214 /* 1215 * If we found no definition and the reference is weak, treat the 1216 * symbol as having the value zero. 1217 */ 1218 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1219 def = &sym_zero; 1220 defobj = obj_main; 1221 } 1222 1223 if (def != NULL) { 1224 *defobj_out = defobj; 1225 /* Record the information in the cache to avoid subsequent lookups. */ 1226 if (cache != NULL) { 1227 cache[symnum].sym = def; 1228 cache[symnum].obj = defobj; 1229 } 1230 } else { 1231 if (refobj != &obj_rtld) 1232 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name); 1233 } 1234 return def; 1235} 1236 1237/* 1238 * Return the search path from the ldconfig hints file, reading it if 1239 * necessary. Returns NULL if there are problems with the hints file, 1240 * or if the search path there is empty. 1241 */ 1242static const char * 1243gethints(void) 1244{ 1245 static char *hints; 1246 1247 if (hints == NULL) { 1248 int fd; 1249 struct elfhints_hdr hdr; 1250 char *p; 1251 1252 /* Keep from trying again in case the hints file is bad. */ 1253 hints = ""; 1254 1255 if ((fd = open(ld_elf_hints_path, O_RDONLY)) == -1) 1256 return NULL; 1257 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1258 hdr.magic != ELFHINTS_MAGIC || 1259 hdr.version != 1) { 1260 close(fd); 1261 return NULL; 1262 } 1263 p = xmalloc(hdr.dirlistlen + 1); 1264 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1265 read(fd, p, hdr.dirlistlen + 1) != (ssize_t)hdr.dirlistlen + 1) { 1266 free(p); 1267 close(fd); 1268 return NULL; 1269 } 1270 hints = p; 1271 close(fd); 1272 } 1273 return hints[0] != '\0' ? hints : NULL; 1274} 1275 1276static void 1277init_dag(Obj_Entry *root) 1278{ 1279 DoneList donelist; 1280 1281 donelist_init(&donelist); 1282 init_dag1(root, root, &donelist); 1283} 1284 1285static void 1286init_dag1(Obj_Entry *root, Obj_Entry *obj, DoneList *dlp) 1287{ 1288 const Needed_Entry *needed; 1289 1290 if (donelist_check(dlp, obj)) 1291 return; 1292 1293 obj->refcount++; 1294 objlist_push_tail(&obj->dldags, root); 1295 objlist_push_tail(&root->dagmembers, obj); 1296 for (needed = obj->needed; needed != NULL; needed = needed->next) 1297 if (needed->obj != NULL) 1298 init_dag1(root, needed->obj, dlp); 1299} 1300 1301/* 1302 * Initialize the dynamic linker. The argument is the address at which 1303 * the dynamic linker has been mapped into memory. The primary task of 1304 * this function is to relocate the dynamic linker. 1305 */ 1306static void 1307init_rtld(caddr_t mapbase) 1308{ 1309 Obj_Entry objtmp; /* Temporary rtld object */ 1310 1311 /* 1312 * Conjure up an Obj_Entry structure for the dynamic linker. 1313 * 1314 * The "path" member can't be initialized yet because string constants 1315 * cannot yet be accessed. Below we will set it correctly. 1316 */ 1317 memset(&objtmp, 0, sizeof(objtmp)); 1318 objtmp.path = NULL; 1319 objtmp.rtld = true; 1320 objtmp.mapbase = mapbase; 1321#ifdef PIC 1322 objtmp.relocbase = mapbase; 1323#endif 1324 if (RTLD_IS_DYNAMIC()) { 1325 objtmp.dynamic = rtld_dynamic(&objtmp); 1326 digest_dynamic(&objtmp, 1); 1327 assert(objtmp.needed == NULL); 1328#if !defined(__mips__) 1329 /* MIPS and SH{3,5} have a bogus DT_TEXTREL. */ 1330 assert(!objtmp.textrel); 1331#endif 1332 1333 /* 1334 * Temporarily put the dynamic linker entry into the object list, so 1335 * that symbols can be found. 1336 */ 1337 1338 relocate_objects(&objtmp, true, &objtmp); 1339 } 1340 1341 /* Initialize the object list. */ 1342 obj_tail = &obj_list; 1343 1344 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1345 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1346 1347 /* Replace the path with a dynamically allocated copy. */ 1348 obj_rtld.path = xstrdup(PATH_RTLD); 1349 1350 r_debug.r_brk = r_debug_state; 1351 r_debug.r_state = RT_CONSISTENT; 1352} 1353 1354/* 1355 * Add the init functions from a needed object list (and its recursive 1356 * needed objects) to "list". This is not used directly; it is a helper 1357 * function for initlist_add_objects(). The write lock must be held 1358 * when this function is called. 1359 */ 1360static void 1361initlist_add_neededs(Needed_Entry *needed, Objlist *list) 1362{ 1363 /* Recursively process the successor needed objects. */ 1364 if (needed->next != NULL) 1365 initlist_add_neededs(needed->next, list); 1366 1367 /* Process the current needed object. */ 1368 if (needed->obj != NULL) 1369 initlist_add_objects(needed->obj, &needed->obj->next, list); 1370} 1371 1372/* 1373 * Scan all of the DAGs rooted in the range of objects from "obj" to 1374 * "tail" and add their init functions to "list". This recurses over 1375 * the DAGs and ensure the proper init ordering such that each object's 1376 * needed libraries are initialized before the object itself. At the 1377 * same time, this function adds the objects to the global finalization 1378 * list "list_fini" in the opposite order. The write lock must be 1379 * held when this function is called. 1380 */ 1381static void 1382initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list) 1383{ 1384 if (obj->init_scanned || obj->init_done) 1385 return; 1386 obj->init_scanned = true; 1387 1388 /* Recursively process the successor objects. */ 1389 if (&obj->next != tail) 1390 initlist_add_objects(obj->next, tail, list); 1391 1392 /* Recursively process the needed objects. */ 1393 if (obj->needed != NULL) 1394 initlist_add_neededs(obj->needed, list); 1395 1396 /* Add the object to the init list. */ 1397 if (obj->init != (Elf_Addr)NULL) 1398 objlist_push_tail(list, obj); 1399 1400 /* Add the object to the global fini list in the reverse order. */ 1401 if (obj->fini != (Elf_Addr)NULL && !obj->on_fini_list) { 1402 objlist_push_head(&list_fini, obj); 1403 obj->on_fini_list = true; 1404 } 1405} 1406 1407#ifndef FPTR_TARGET 1408#define FPTR_TARGET(f) ((Elf_Addr) (f)) 1409#endif 1410 1411static bool 1412is_exported(const Elf_Sym *def) 1413{ 1414 Elf_Addr value; 1415 const func_ptr_type *p; 1416 1417 value = (Elf_Addr)(obj_rtld.relocbase + def->st_value); 1418 for (p = exports; *p != NULL; p++) 1419 if (FPTR_TARGET(*p) == value) 1420 return true; 1421 return false; 1422} 1423 1424/* 1425 * Given a shared object, traverse its list of needed objects, and load 1426 * each of them. Returns 0 on success. Generates an error message and 1427 * returns -1 on failure. 1428 */ 1429static int 1430load_needed_objects(Obj_Entry *first, int flags) 1431{ 1432 Obj_Entry *obj, *obj1; 1433 1434 for (obj = first; obj != NULL; obj = obj->next) { 1435 Needed_Entry *needed; 1436 1437 for (needed = obj->needed; needed != NULL; needed = needed->next) { 1438 obj1 = needed->obj = load_object(obj->strtab + needed->name, obj, 1439 flags & ~RTLD_LO_NOLOAD); 1440 if (obj1 == NULL && !ld_tracing) 1441 return -1; 1442 if (obj1 != NULL && obj1->z_nodelete && !obj1->ref_nodel) { 1443 dbg("obj %s nodelete", obj1->path); 1444 init_dag(obj1); 1445 ref_dag(obj1); 1446 obj1->ref_nodel = true; 1447 } 1448 } 1449 } 1450 1451 return 0; 1452} 1453 1454static int 1455load_preload_objects(void) 1456{ 1457 char *p = ld_preload; 1458 static const char delim[] = " \t:;"; 1459 1460 if (p == NULL) 1461 return 0; 1462 1463 p += strspn(p, delim); 1464 while (*p != '\0') { 1465 size_t len = strcspn(p, delim); 1466 char savech; 1467 1468 savech = p[len]; 1469 p[len] = '\0'; 1470 if (load_object(p, NULL, 0) == NULL) 1471 return -1; /* XXX - cleanup */ 1472 p[len] = savech; 1473 p += len; 1474 p += strspn(p, delim); 1475 } 1476 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 1477 return 0; 1478} 1479 1480/* 1481 * Load a shared object into memory, if it is not already loaded. 1482 * 1483 * Returns a pointer to the Obj_Entry for the object. Returns NULL 1484 * on failure. 1485 */ 1486static Obj_Entry * 1487load_object(const char *name, const Obj_Entry *refobj, int flags) 1488{ 1489 Obj_Entry *obj; 1490 int fd = -1; 1491 struct stat sb; 1492 char *path; 1493 1494 for (obj = obj_list->next; obj != NULL; obj = obj->next) 1495 if (object_match_name(obj, name)) 1496 return obj; 1497 1498 path = find_library(name, refobj); 1499 if (path == NULL) 1500 return NULL; 1501 1502 /* 1503 * If we didn't find a match by pathname, open the file and check 1504 * again by device and inode. This avoids false mismatches caused 1505 * by multiple links or ".." in pathnames. 1506 * 1507 * To avoid a race, we open the file and use fstat() rather than 1508 * using stat(). 1509 */ 1510 if ((fd = open(path, O_RDONLY)) == -1) { 1511 _rtld_error("Cannot open \"%s\"", path); 1512 free(path); 1513 return NULL; 1514 } 1515 if (fstat(fd, &sb) == -1) { 1516 _rtld_error("Cannot fstat \"%s\"", path); 1517 close(fd); 1518 free(path); 1519 return NULL; 1520 } 1521 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 1522 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) { 1523 close(fd); 1524 break; 1525 } 1526 } 1527 if (obj != NULL) { 1528 object_add_name(obj, name); 1529 free(path); 1530 close(fd); 1531 return obj; 1532 } 1533 if (flags & RTLD_LO_NOLOAD) 1534 return (NULL); 1535 1536 /* First use of this object, so we must map it in */ 1537 obj = do_load_object(fd, name, path, &sb, flags); 1538 if (obj == NULL) 1539 free(path); 1540 close(fd); 1541 1542 return obj; 1543} 1544 1545static Obj_Entry * 1546do_load_object(int fd, const char *name, char *path, struct stat *sbp, 1547 int flags) 1548{ 1549 Obj_Entry *obj; 1550 struct statfs fs; 1551 1552 /* 1553 * but first, make sure that environment variables haven't been 1554 * used to circumvent the noexec flag on a filesystem. 1555 */ 1556 if (dangerous_ld_env) { 1557 if (fstatfs(fd, &fs) != 0) { 1558 _rtld_error("Cannot fstatfs \"%s\"", path); 1559 return NULL; 1560 } 1561 if (fs.f_flags & MNT_NOEXEC) { 1562 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 1563 return NULL; 1564 } 1565 } 1566 dbg("loading \"%s\"", path); 1567 obj = map_object(fd, path, sbp); 1568 if (obj == NULL) 1569 return NULL; 1570 1571 object_add_name(obj, name); 1572 obj->path = path; 1573 digest_dynamic(obj, 0); 1574 if (obj->z_noopen && (flags & RTLD_LO_DLOPEN)) { 1575 dbg("refusing to load non-loadable \"%s\"", obj->path); 1576 _rtld_error("Cannot dlopen non-loadable %s\n", obj->path); 1577 munmap(obj->mapbase, obj->mapsize); 1578 obj_free(obj); 1579 return (NULL); 1580 } 1581 1582 *obj_tail = obj; 1583 obj_tail = &obj->next; 1584 obj_count++; 1585 obj_loads++; 1586 linkmap_add(obj); /* for GDB & dlinfo() */ 1587 1588 dbg(" %p .. %p: %s", obj->mapbase, 1589 obj->mapbase + obj->mapsize - 1, obj->path); 1590 if (obj->textrel) 1591 dbg(" WARNING: %s has impure text", obj->path); 1592 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 1593 obj->path); 1594 1595 return obj; 1596} 1597 1598static Obj_Entry * 1599obj_from_addr(const void *addr) 1600{ 1601 Obj_Entry *obj; 1602 1603 for (obj = obj_list; obj != NULL; obj = obj->next) { 1604 if (addr < (void *) obj->mapbase) 1605 continue; 1606 if (addr < (void *) (obj->mapbase + obj->mapsize)) 1607 return obj; 1608 } 1609 return NULL; 1610} 1611 1612/* 1613 * Call the finalization functions for each of the objects in "list" 1614 * which are unreferenced. All of the objects are expected to have 1615 * non-NULL fini functions. 1616 */ 1617static void 1618objlist_call_fini(Objlist *list, bool force, int *lockstate) 1619{ 1620 Objlist_Entry *elm, *elm_tmp; 1621 char *saved_msg; 1622 1623 /* 1624 * Preserve the current error message since a fini function might 1625 * call into the dynamic linker and overwrite it. 1626 */ 1627 saved_msg = errmsg_save(); 1628 STAILQ_FOREACH_SAFE(elm, list, link, elm_tmp) { 1629 if (elm->obj->refcount == 0 || force) { 1630 dbg("calling fini function for %s at %p", elm->obj->path, 1631 (void *)elm->obj->fini); 1632 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 0, 0, 1633 elm->obj->path); 1634 /* Remove object from fini list to prevent recursive invocation. */ 1635 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 1636 wlock_release(rtld_bind_lock, *lockstate); 1637 call_initfini_pointer(elm->obj, elm->obj->fini); 1638 *lockstate = wlock_acquire(rtld_bind_lock); 1639 /* No need to free anything if process is going down. */ 1640 if (!force) 1641 free(elm); 1642 } 1643 } 1644 errmsg_restore(saved_msg); 1645} 1646 1647/* 1648 * Call the initialization functions for each of the objects in 1649 * "list". All of the objects are expected to have non-NULL init 1650 * functions. 1651 */ 1652static void 1653objlist_call_init(Objlist *list, int *lockstate) 1654{ 1655 Objlist_Entry *elm; 1656 Obj_Entry *obj; 1657 char *saved_msg; 1658 1659 /* 1660 * Clean init_scanned flag so that objects can be rechecked and 1661 * possibly initialized earlier if any of vectors called below 1662 * cause the change by using dlopen. 1663 */ 1664 for (obj = obj_list; obj != NULL; obj = obj->next) 1665 obj->init_scanned = false; 1666 1667 /* 1668 * Preserve the current error message since an init function might 1669 * call into the dynamic linker and overwrite it. 1670 */ 1671 saved_msg = errmsg_save(); 1672 STAILQ_FOREACH(elm, list, link) { 1673 if (elm->obj->init_done) /* Initialized early. */ 1674 continue; 1675 dbg("calling init function for %s at %p", elm->obj->path, 1676 (void *)elm->obj->init); 1677 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 0, 0, 1678 elm->obj->path); 1679 /* 1680 * Race: other thread might try to use this object before current 1681 * one completes the initilization. Not much can be done here 1682 * without better locking. 1683 */ 1684 elm->obj->init_done = true; 1685 wlock_release(rtld_bind_lock, *lockstate); 1686 call_initfini_pointer(elm->obj, elm->obj->init); 1687 *lockstate = wlock_acquire(rtld_bind_lock); 1688 } 1689 errmsg_restore(saved_msg); 1690} 1691 1692static void 1693objlist_clear(Objlist *list) 1694{ 1695 Objlist_Entry *elm; 1696 1697 while (!STAILQ_EMPTY(list)) { 1698 elm = STAILQ_FIRST(list); 1699 STAILQ_REMOVE_HEAD(list, link); 1700 free(elm); 1701 } 1702} 1703 1704static Objlist_Entry * 1705objlist_find(Objlist *list, const Obj_Entry *obj) 1706{ 1707 Objlist_Entry *elm; 1708 1709 STAILQ_FOREACH(elm, list, link) 1710 if (elm->obj == obj) 1711 return elm; 1712 return NULL; 1713} 1714 1715static void 1716objlist_init(Objlist *list) 1717{ 1718 STAILQ_INIT(list); 1719} 1720 1721static void 1722objlist_push_head(Objlist *list, Obj_Entry *obj) 1723{ 1724 Objlist_Entry *elm; 1725 1726 elm = NEW(Objlist_Entry); 1727 elm->obj = obj; 1728 STAILQ_INSERT_HEAD(list, elm, link); 1729} 1730 1731static void 1732objlist_push_tail(Objlist *list, Obj_Entry *obj) 1733{ 1734 Objlist_Entry *elm; 1735 1736 elm = NEW(Objlist_Entry); 1737 elm->obj = obj; 1738 STAILQ_INSERT_TAIL(list, elm, link); 1739} 1740 1741static void 1742objlist_remove(Objlist *list, Obj_Entry *obj) 1743{ 1744 Objlist_Entry *elm; 1745 1746 if ((elm = objlist_find(list, obj)) != NULL) { 1747 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 1748 free(elm); 1749 } 1750} 1751 1752/* 1753 * Relocate newly-loaded shared objects. The argument is a pointer to 1754 * the Obj_Entry for the first such object. All objects from the first 1755 * to the end of the list of objects are relocated. Returns 0 on success, 1756 * or -1 on failure. 1757 */ 1758static int 1759relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj) 1760{ 1761 Obj_Entry *obj; 1762 1763 for (obj = first; obj != NULL; obj = obj->next) { 1764 if (obj != rtldobj) 1765 dbg("relocating \"%s\"", obj->path); 1766 if (obj->nbuckets == 0 || obj->nchains == 0 || obj->buckets == NULL || 1767 obj->symtab == NULL || obj->strtab == NULL) { 1768 _rtld_error("%s: Shared object has no run-time symbol table", 1769 obj->path); 1770 return -1; 1771 } 1772 1773 if (obj->textrel) { 1774 /* There are relocations to the write-protected text segment. */ 1775 if (mprotect(obj->mapbase, obj->textsize, 1776 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) { 1777 _rtld_error("%s: Cannot write-enable text segment: %s", 1778 obj->path, strerror(errno)); 1779 return -1; 1780 } 1781 } 1782 1783 /* Process the non-PLT relocations. */ 1784 if (reloc_non_plt(obj, rtldobj)) 1785 return -1; 1786 1787 if (obj->textrel) { /* Re-protected the text segment. */ 1788 if (mprotect(obj->mapbase, obj->textsize, 1789 PROT_READ|PROT_EXEC) == -1) { 1790 _rtld_error("%s: Cannot write-protect text segment: %s", 1791 obj->path, strerror(errno)); 1792 return -1; 1793 } 1794 } 1795 1796 /* Process the PLT relocations. */ 1797 if (reloc_plt(obj) == -1) 1798 return -1; 1799 /* Relocate the jump slots if we are doing immediate binding. */ 1800 if (obj->bind_now || bind_now) 1801 if (reloc_jmpslots(obj) == -1) 1802 return -1; 1803 1804 1805 /* 1806 * Set up the magic number and version in the Obj_Entry. These 1807 * were checked in the crt1.o from the original ElfKit, so we 1808 * set them for backward compatibility. 1809 */ 1810 obj->magic = RTLD_MAGIC; 1811 obj->version = RTLD_VERSION; 1812 1813 /* Set the special PLT or GOT entries. */ 1814 init_pltgot(obj); 1815 } 1816 1817 return 0; 1818} 1819 1820/* 1821 * Cleanup procedure. It will be called (by the atexit mechanism) just 1822 * before the process exits. 1823 */ 1824static void 1825rtld_exit(void) 1826{ 1827 int lockstate; 1828 1829 lockstate = wlock_acquire(rtld_bind_lock); 1830 dbg("rtld_exit()"); 1831 objlist_call_fini(&list_fini, true, &lockstate); 1832 /* No need to remove the items from the list, since we are exiting. */ 1833 if (!libmap_disable) 1834 lm_fini(); 1835 wlock_release(rtld_bind_lock, lockstate); 1836} 1837 1838static void * 1839path_enumerate(const char *path, path_enum_proc callback, void *arg) 1840{ 1841#ifdef COMPAT_32BIT 1842 const char *trans; 1843#endif 1844 if (path == NULL) 1845 return (NULL); 1846 1847 path += strspn(path, ":;"); 1848 while (*path != '\0') { 1849 size_t len; 1850 char *res; 1851 1852 len = strcspn(path, ":;"); 1853#ifdef COMPAT_32BIT 1854 trans = lm_findn(NULL, path, len); 1855 if (trans) 1856 res = callback(trans, strlen(trans), arg); 1857 else 1858#endif 1859 res = callback(path, len, arg); 1860 1861 if (res != NULL) 1862 return (res); 1863 1864 path += len; 1865 path += strspn(path, ":;"); 1866 } 1867 1868 return (NULL); 1869} 1870 1871struct try_library_args { 1872 const char *name; 1873 size_t namelen; 1874 char *buffer; 1875 size_t buflen; 1876}; 1877 1878static void * 1879try_library_path(const char *dir, size_t dirlen, void *param) 1880{ 1881 struct try_library_args *arg; 1882 1883 arg = param; 1884 if (*dir == '/' || trust) { 1885 char *pathname; 1886 1887 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 1888 return (NULL); 1889 1890 pathname = arg->buffer; 1891 strncpy(pathname, dir, dirlen); 1892 pathname[dirlen] = '/'; 1893 strcpy(pathname + dirlen + 1, arg->name); 1894 1895 dbg(" Trying \"%s\"", pathname); 1896 if (access(pathname, F_OK) == 0) { /* We found it */ 1897 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 1898 strcpy(pathname, arg->buffer); 1899 return (pathname); 1900 } 1901 } 1902 return (NULL); 1903} 1904 1905static char * 1906search_library_path(const char *name, const char *path) 1907{ 1908 char *p; 1909 struct try_library_args arg; 1910 1911 if (path == NULL) 1912 return NULL; 1913 1914 arg.name = name; 1915 arg.namelen = strlen(name); 1916 arg.buffer = xmalloc(PATH_MAX); 1917 arg.buflen = PATH_MAX; 1918 1919 p = path_enumerate(path, try_library_path, &arg); 1920 1921 free(arg.buffer); 1922 1923 return (p); 1924} 1925 1926int 1927dlclose(void *handle) 1928{ 1929 Obj_Entry *root; 1930 int lockstate; 1931 1932 lockstate = wlock_acquire(rtld_bind_lock); 1933 root = dlcheck(handle); 1934 if (root == NULL) { 1935 wlock_release(rtld_bind_lock, lockstate); 1936 return -1; 1937 } 1938 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 1939 root->path); 1940 1941 /* Unreference the object and its dependencies. */ 1942 root->dl_refcount--; 1943 1944 unref_dag(root); 1945 1946 if (root->refcount == 0) { 1947 /* 1948 * The object is no longer referenced, so we must unload it. 1949 * First, call the fini functions. 1950 */ 1951 objlist_call_fini(&list_fini, false, &lockstate); 1952 1953 /* Finish cleaning up the newly-unreferenced objects. */ 1954 GDB_STATE(RT_DELETE,&root->linkmap); 1955 unload_object(root); 1956 GDB_STATE(RT_CONSISTENT,NULL); 1957 } 1958 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 1959 wlock_release(rtld_bind_lock, lockstate); 1960 return 0; 1961} 1962 1963const char * 1964dlerror(void) 1965{ 1966 char *msg = error_message; 1967 error_message = NULL; 1968 return msg; 1969} 1970 1971/* 1972 * This function is deprecated and has no effect. 1973 */ 1974void 1975dllockinit(void *context, 1976 void *(*lock_create)(void *context), 1977 void (*rlock_acquire)(void *lock), 1978 void (*wlock_acquire)(void *lock), 1979 void (*lock_release)(void *lock), 1980 void (*lock_destroy)(void *lock), 1981 void (*context_destroy)(void *context)) 1982{ 1983 static void *cur_context; 1984 static void (*cur_context_destroy)(void *); 1985 1986 /* Just destroy the context from the previous call, if necessary. */ 1987 if (cur_context_destroy != NULL) 1988 cur_context_destroy(cur_context); 1989 cur_context = context; 1990 cur_context_destroy = context_destroy; 1991} 1992 1993void * 1994dlopen(const char *name, int mode) 1995{ 1996 Obj_Entry **old_obj_tail; 1997 Obj_Entry *obj; 1998 Objlist initlist; 1999 int result, lockstate, nodelete, lo_flags; 2000 2001 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 2002 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 2003 if (ld_tracing != NULL) 2004 environ = (char **)*get_program_var_addr("environ"); 2005 nodelete = mode & RTLD_NODELETE; 2006 lo_flags = RTLD_LO_DLOPEN; 2007 if (mode & RTLD_NOLOAD) 2008 lo_flags |= RTLD_LO_NOLOAD; 2009 2010 objlist_init(&initlist); 2011 2012 lockstate = wlock_acquire(rtld_bind_lock); 2013 GDB_STATE(RT_ADD,NULL); 2014 2015 old_obj_tail = obj_tail; 2016 obj = NULL; 2017 if (name == NULL) { 2018 obj = obj_main; 2019 obj->refcount++; 2020 } else { 2021 obj = load_object(name, obj_main, lo_flags); 2022 } 2023 2024 if (obj) { 2025 obj->dl_refcount++; 2026 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 2027 objlist_push_tail(&list_global, obj); 2028 mode &= RTLD_MODEMASK; 2029 if (*old_obj_tail != NULL) { /* We loaded something new. */ 2030 assert(*old_obj_tail == obj); 2031 result = load_needed_objects(obj, RTLD_LO_DLOPEN); 2032 init_dag(obj); 2033 if (result != -1) 2034 result = rtld_verify_versions(&obj->dagmembers); 2035 if (result != -1 && ld_tracing) 2036 goto trace; 2037 if (result == -1 || 2038 (relocate_objects(obj, mode == RTLD_NOW, &obj_rtld)) == -1) { 2039 obj->dl_refcount--; 2040 unref_dag(obj); 2041 if (obj->refcount == 0) 2042 unload_object(obj); 2043 obj = NULL; 2044 } else { 2045 /* Make list of init functions to call. */ 2046 initlist_add_objects(obj, &obj->next, &initlist); 2047 } 2048 } else { 2049 2050 /* Bump the reference counts for objects on this DAG. */ 2051 ref_dag(obj); 2052 2053 if (ld_tracing) 2054 goto trace; 2055 } 2056 if (obj != NULL && (nodelete || obj->z_nodelete) && !obj->ref_nodel) { 2057 dbg("obj %s nodelete", obj->path); 2058 ref_dag(obj); 2059 obj->z_nodelete = obj->ref_nodel = true; 2060 } 2061 } 2062 2063 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 2064 name); 2065 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 2066 2067 /* Call the init functions. */ 2068 objlist_call_init(&initlist, &lockstate); 2069 objlist_clear(&initlist); 2070 wlock_release(rtld_bind_lock, lockstate); 2071 return obj; 2072trace: 2073 trace_loaded_objects(obj); 2074 wlock_release(rtld_bind_lock, lockstate); 2075 exit(0); 2076} 2077 2078static void * 2079do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 2080 int flags) 2081{ 2082 DoneList donelist; 2083 const Obj_Entry *obj, *defobj; 2084 const Elf_Sym *def, *symp; 2085 unsigned long hash; 2086 int lockstate; 2087 2088 hash = elf_hash(name); 2089 def = NULL; 2090 defobj = NULL; 2091 flags |= SYMLOOK_IN_PLT; 2092 2093 lockstate = rlock_acquire(rtld_bind_lock); 2094 if (handle == NULL || handle == RTLD_NEXT || 2095 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 2096 2097 if ((obj = obj_from_addr(retaddr)) == NULL) { 2098 _rtld_error("Cannot determine caller's shared object"); 2099 rlock_release(rtld_bind_lock, lockstate); 2100 return NULL; 2101 } 2102 if (handle == NULL) { /* Just the caller's shared object. */ 2103 def = symlook_obj(name, hash, obj, ve, flags); 2104 defobj = obj; 2105 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 2106 handle == RTLD_SELF) { /* ... caller included */ 2107 if (handle == RTLD_NEXT) 2108 obj = obj->next; 2109 for (; obj != NULL; obj = obj->next) { 2110 if ((symp = symlook_obj(name, hash, obj, ve, flags)) != NULL) { 2111 if (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK) { 2112 def = symp; 2113 defobj = obj; 2114 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 2115 break; 2116 } 2117 } 2118 } 2119 /* 2120 * Search the dynamic linker itself, and possibly resolve the 2121 * symbol from there. This is how the application links to 2122 * dynamic linker services such as dlopen. Only the values listed 2123 * in the "exports" array can be resolved from the dynamic linker. 2124 */ 2125 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2126 symp = symlook_obj(name, hash, &obj_rtld, ve, flags); 2127 if (symp != NULL && is_exported(symp)) { 2128 def = symp; 2129 defobj = &obj_rtld; 2130 } 2131 } 2132 } else { 2133 assert(handle == RTLD_DEFAULT); 2134 def = symlook_default(name, hash, obj, &defobj, ve, flags); 2135 } 2136 } else { 2137 if ((obj = dlcheck(handle)) == NULL) { 2138 rlock_release(rtld_bind_lock, lockstate); 2139 return NULL; 2140 } 2141 2142 donelist_init(&donelist); 2143 if (obj->mainprog) { 2144 /* Search main program and all libraries loaded by it. */ 2145 def = symlook_list(name, hash, &list_main, &defobj, ve, flags, 2146 &donelist); 2147 2148 /* 2149 * We do not distinguish between 'main' object and global scope. 2150 * If symbol is not defined by objects loaded at startup, continue 2151 * search among dynamically loaded objects with RTLD_GLOBAL 2152 * scope. 2153 */ 2154 if (def == NULL) 2155 def = symlook_list(name, hash, &list_global, &defobj, ve, 2156 flags, &donelist); 2157 } else { 2158 Needed_Entry fake; 2159 2160 /* Search the whole DAG rooted at the given object. */ 2161 fake.next = NULL; 2162 fake.obj = (Obj_Entry *)obj; 2163 fake.name = 0; 2164 def = symlook_needed(name, hash, &fake, &defobj, ve, flags, 2165 &donelist); 2166 } 2167 } 2168 2169 if (def != NULL) { 2170 rlock_release(rtld_bind_lock, lockstate); 2171 2172 /* 2173 * The value required by the caller is derived from the value 2174 * of the symbol. For the ia64 architecture, we need to 2175 * construct a function descriptor which the caller can use to 2176 * call the function with the right 'gp' value. For other 2177 * architectures and for non-functions, the value is simply 2178 * the relocated value of the symbol. 2179 */ 2180 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 2181 return make_function_pointer(def, defobj); 2182 else 2183 return defobj->relocbase + def->st_value; 2184 } 2185 2186 _rtld_error("Undefined symbol \"%s\"", name); 2187 rlock_release(rtld_bind_lock, lockstate); 2188 return NULL; 2189} 2190 2191void * 2192dlsym(void *handle, const char *name) 2193{ 2194 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 2195 SYMLOOK_DLSYM); 2196} 2197 2198dlfunc_t 2199dlfunc(void *handle, const char *name) 2200{ 2201 union { 2202 void *d; 2203 dlfunc_t f; 2204 } rv; 2205 2206 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 2207 SYMLOOK_DLSYM); 2208 return (rv.f); 2209} 2210 2211void * 2212dlvsym(void *handle, const char *name, const char *version) 2213{ 2214 Ver_Entry ventry; 2215 2216 ventry.name = version; 2217 ventry.file = NULL; 2218 ventry.hash = elf_hash(version); 2219 ventry.flags= 0; 2220 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 2221 SYMLOOK_DLSYM); 2222} 2223 2224int 2225dladdr(const void *addr, Dl_info *info) 2226{ 2227 const Obj_Entry *obj; 2228 const Elf_Sym *def; 2229 void *symbol_addr; 2230 unsigned long symoffset; 2231 int lockstate; 2232 2233 lockstate = rlock_acquire(rtld_bind_lock); 2234 obj = obj_from_addr(addr); 2235 if (obj == NULL) { 2236 _rtld_error("No shared object contains address"); 2237 rlock_release(rtld_bind_lock, lockstate); 2238 return 0; 2239 } 2240 info->dli_fname = obj->path; 2241 info->dli_fbase = obj->mapbase; 2242 info->dli_saddr = (void *)0; 2243 info->dli_sname = NULL; 2244 2245 /* 2246 * Walk the symbol list looking for the symbol whose address is 2247 * closest to the address sent in. 2248 */ 2249 for (symoffset = 0; symoffset < obj->nchains; symoffset++) { 2250 def = obj->symtab + symoffset; 2251 2252 /* 2253 * For skip the symbol if st_shndx is either SHN_UNDEF or 2254 * SHN_COMMON. 2255 */ 2256 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 2257 continue; 2258 2259 /* 2260 * If the symbol is greater than the specified address, or if it 2261 * is further away from addr than the current nearest symbol, 2262 * then reject it. 2263 */ 2264 symbol_addr = obj->relocbase + def->st_value; 2265 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 2266 continue; 2267 2268 /* Update our idea of the nearest symbol. */ 2269 info->dli_sname = obj->strtab + def->st_name; 2270 info->dli_saddr = symbol_addr; 2271 2272 /* Exact match? */ 2273 if (info->dli_saddr == addr) 2274 break; 2275 } 2276 rlock_release(rtld_bind_lock, lockstate); 2277 return 1; 2278} 2279 2280int 2281dlinfo(void *handle, int request, void *p) 2282{ 2283 const Obj_Entry *obj; 2284 int error, lockstate; 2285 2286 lockstate = rlock_acquire(rtld_bind_lock); 2287 2288 if (handle == NULL || handle == RTLD_SELF) { 2289 void *retaddr; 2290 2291 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 2292 if ((obj = obj_from_addr(retaddr)) == NULL) 2293 _rtld_error("Cannot determine caller's shared object"); 2294 } else 2295 obj = dlcheck(handle); 2296 2297 if (obj == NULL) { 2298 rlock_release(rtld_bind_lock, lockstate); 2299 return (-1); 2300 } 2301 2302 error = 0; 2303 switch (request) { 2304 case RTLD_DI_LINKMAP: 2305 *((struct link_map const **)p) = &obj->linkmap; 2306 break; 2307 case RTLD_DI_ORIGIN: 2308 error = rtld_dirname(obj->path, p); 2309 break; 2310 2311 case RTLD_DI_SERINFOSIZE: 2312 case RTLD_DI_SERINFO: 2313 error = do_search_info(obj, request, (struct dl_serinfo *)p); 2314 break; 2315 2316 default: 2317 _rtld_error("Invalid request %d passed to dlinfo()", request); 2318 error = -1; 2319 } 2320 2321 rlock_release(rtld_bind_lock, lockstate); 2322 2323 return (error); 2324} 2325 2326int 2327dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 2328{ 2329 struct dl_phdr_info phdr_info; 2330 const Obj_Entry *obj; 2331 int error, bind_lockstate, phdr_lockstate; 2332 2333 phdr_lockstate = wlock_acquire(rtld_phdr_lock); 2334 bind_lockstate = rlock_acquire(rtld_bind_lock); 2335 2336 error = 0; 2337 2338 for (obj = obj_list; obj != NULL; obj = obj->next) { 2339 phdr_info.dlpi_addr = (Elf_Addr)obj->relocbase; 2340 phdr_info.dlpi_name = STAILQ_FIRST(&obj->names) ? 2341 STAILQ_FIRST(&obj->names)->name : obj->path; 2342 phdr_info.dlpi_phdr = obj->phdr; 2343 phdr_info.dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 2344 phdr_info.dlpi_tls_modid = obj->tlsindex; 2345 phdr_info.dlpi_tls_data = obj->tlsinit; 2346 phdr_info.dlpi_adds = obj_loads; 2347 phdr_info.dlpi_subs = obj_loads - obj_count; 2348 2349 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0) 2350 break; 2351 2352 } 2353 rlock_release(rtld_bind_lock, bind_lockstate); 2354 wlock_release(rtld_phdr_lock, phdr_lockstate); 2355 2356 return (error); 2357} 2358 2359struct fill_search_info_args { 2360 int request; 2361 unsigned int flags; 2362 Dl_serinfo *serinfo; 2363 Dl_serpath *serpath; 2364 char *strspace; 2365}; 2366 2367static void * 2368fill_search_info(const char *dir, size_t dirlen, void *param) 2369{ 2370 struct fill_search_info_args *arg; 2371 2372 arg = param; 2373 2374 if (arg->request == RTLD_DI_SERINFOSIZE) { 2375 arg->serinfo->dls_cnt ++; 2376 arg->serinfo->dls_size += sizeof(Dl_serpath) + dirlen + 1; 2377 } else { 2378 struct dl_serpath *s_entry; 2379 2380 s_entry = arg->serpath; 2381 s_entry->dls_name = arg->strspace; 2382 s_entry->dls_flags = arg->flags; 2383 2384 strncpy(arg->strspace, dir, dirlen); 2385 arg->strspace[dirlen] = '\0'; 2386 2387 arg->strspace += dirlen + 1; 2388 arg->serpath++; 2389 } 2390 2391 return (NULL); 2392} 2393 2394static int 2395do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 2396{ 2397 struct dl_serinfo _info; 2398 struct fill_search_info_args args; 2399 2400 args.request = RTLD_DI_SERINFOSIZE; 2401 args.serinfo = &_info; 2402 2403 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2404 _info.dls_cnt = 0; 2405 2406 path_enumerate(ld_library_path, fill_search_info, &args); 2407 path_enumerate(obj->rpath, fill_search_info, &args); 2408 path_enumerate(gethints(), fill_search_info, &args); 2409 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 2410 2411 2412 if (request == RTLD_DI_SERINFOSIZE) { 2413 info->dls_size = _info.dls_size; 2414 info->dls_cnt = _info.dls_cnt; 2415 return (0); 2416 } 2417 2418 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 2419 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 2420 return (-1); 2421 } 2422 2423 args.request = RTLD_DI_SERINFO; 2424 args.serinfo = info; 2425 args.serpath = &info->dls_serpath[0]; 2426 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 2427 2428 args.flags = LA_SER_LIBPATH; 2429 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 2430 return (-1); 2431 2432 args.flags = LA_SER_RUNPATH; 2433 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 2434 return (-1); 2435 2436 args.flags = LA_SER_CONFIG; 2437 if (path_enumerate(gethints(), fill_search_info, &args) != NULL) 2438 return (-1); 2439 2440 args.flags = LA_SER_DEFAULT; 2441 if (path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 2442 return (-1); 2443 return (0); 2444} 2445 2446static int 2447rtld_dirname(const char *path, char *bname) 2448{ 2449 const char *endp; 2450 2451 /* Empty or NULL string gets treated as "." */ 2452 if (path == NULL || *path == '\0') { 2453 bname[0] = '.'; 2454 bname[1] = '\0'; 2455 return (0); 2456 } 2457 2458 /* Strip trailing slashes */ 2459 endp = path + strlen(path) - 1; 2460 while (endp > path && *endp == '/') 2461 endp--; 2462 2463 /* Find the start of the dir */ 2464 while (endp > path && *endp != '/') 2465 endp--; 2466 2467 /* Either the dir is "/" or there are no slashes */ 2468 if (endp == path) { 2469 bname[0] = *endp == '/' ? '/' : '.'; 2470 bname[1] = '\0'; 2471 return (0); 2472 } else { 2473 do { 2474 endp--; 2475 } while (endp > path && *endp == '/'); 2476 } 2477 2478 if (endp - path + 2 > PATH_MAX) 2479 { 2480 _rtld_error("Filename is too long: %s", path); 2481 return(-1); 2482 } 2483 2484 strncpy(bname, path, endp - path + 1); 2485 bname[endp - path + 1] = '\0'; 2486 return (0); 2487} 2488 2489static int 2490rtld_dirname_abs(const char *path, char *base) 2491{ 2492 char base_rel[PATH_MAX]; 2493 2494 if (rtld_dirname(path, base) == -1) 2495 return (-1); 2496 if (base[0] == '/') 2497 return (0); 2498 if (getcwd(base_rel, sizeof(base_rel)) == NULL || 2499 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) || 2500 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel)) 2501 return (-1); 2502 strcpy(base, base_rel); 2503 return (0); 2504} 2505 2506static void 2507linkmap_add(Obj_Entry *obj) 2508{ 2509 struct link_map *l = &obj->linkmap; 2510 struct link_map *prev; 2511 2512 obj->linkmap.l_name = obj->path; 2513 obj->linkmap.l_addr = obj->mapbase; 2514 obj->linkmap.l_ld = obj->dynamic; 2515#ifdef __mips__ 2516 /* GDB needs load offset on MIPS to use the symbols */ 2517 obj->linkmap.l_offs = obj->relocbase; 2518#endif 2519 2520 if (r_debug.r_map == NULL) { 2521 r_debug.r_map = l; 2522 return; 2523 } 2524 2525 /* 2526 * Scan to the end of the list, but not past the entry for the 2527 * dynamic linker, which we want to keep at the very end. 2528 */ 2529 for (prev = r_debug.r_map; 2530 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 2531 prev = prev->l_next) 2532 ; 2533 2534 /* Link in the new entry. */ 2535 l->l_prev = prev; 2536 l->l_next = prev->l_next; 2537 if (l->l_next != NULL) 2538 l->l_next->l_prev = l; 2539 prev->l_next = l; 2540} 2541 2542static void 2543linkmap_delete(Obj_Entry *obj) 2544{ 2545 struct link_map *l = &obj->linkmap; 2546 2547 if (l->l_prev == NULL) { 2548 if ((r_debug.r_map = l->l_next) != NULL) 2549 l->l_next->l_prev = NULL; 2550 return; 2551 } 2552 2553 if ((l->l_prev->l_next = l->l_next) != NULL) 2554 l->l_next->l_prev = l->l_prev; 2555} 2556 2557/* 2558 * Function for the debugger to set a breakpoint on to gain control. 2559 * 2560 * The two parameters allow the debugger to easily find and determine 2561 * what the runtime loader is doing and to whom it is doing it. 2562 * 2563 * When the loadhook trap is hit (r_debug_state, set at program 2564 * initialization), the arguments can be found on the stack: 2565 * 2566 * +8 struct link_map *m 2567 * +4 struct r_debug *rd 2568 * +0 RetAddr 2569 */ 2570void 2571r_debug_state(struct r_debug* rd, struct link_map *m) 2572{ 2573} 2574 2575/* 2576 * Get address of the pointer variable in the main program. 2577 */ 2578static const void ** 2579get_program_var_addr(const char *name) 2580{ 2581 const Obj_Entry *obj; 2582 unsigned long hash; 2583 2584 hash = elf_hash(name); 2585 for (obj = obj_main; obj != NULL; obj = obj->next) { 2586 const Elf_Sym *def; 2587 2588 if ((def = symlook_obj(name, hash, obj, NULL, 0)) != NULL) { 2589 const void **addr; 2590 2591 addr = (const void **)(obj->relocbase + def->st_value); 2592 return addr; 2593 } 2594 } 2595 return NULL; 2596} 2597 2598/* 2599 * Set a pointer variable in the main program to the given value. This 2600 * is used to set key variables such as "environ" before any of the 2601 * init functions are called. 2602 */ 2603static void 2604set_program_var(const char *name, const void *value) 2605{ 2606 const void **addr; 2607 2608 if ((addr = get_program_var_addr(name)) != NULL) { 2609 dbg("\"%s\": *%p <-- %p", name, addr, value); 2610 *addr = value; 2611 } 2612} 2613 2614/* 2615 * Given a symbol name in a referencing object, find the corresponding 2616 * definition of the symbol. Returns a pointer to the symbol, or NULL if 2617 * no definition was found. Returns a pointer to the Obj_Entry of the 2618 * defining object via the reference parameter DEFOBJ_OUT. 2619 */ 2620static const Elf_Sym * 2621symlook_default(const char *name, unsigned long hash, const Obj_Entry *refobj, 2622 const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags) 2623{ 2624 DoneList donelist; 2625 const Elf_Sym *def; 2626 const Elf_Sym *symp; 2627 const Obj_Entry *obj; 2628 const Obj_Entry *defobj; 2629 const Objlist_Entry *elm; 2630 def = NULL; 2631 defobj = NULL; 2632 donelist_init(&donelist); 2633 2634 /* Look first in the referencing object if linked symbolically. */ 2635 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 2636 symp = symlook_obj(name, hash, refobj, ventry, flags); 2637 if (symp != NULL) { 2638 def = symp; 2639 defobj = refobj; 2640 } 2641 } 2642 2643 /* Search all objects loaded at program start up. */ 2644 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2645 symp = symlook_list(name, hash, &list_main, &obj, ventry, flags, 2646 &donelist); 2647 if (symp != NULL && 2648 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { 2649 def = symp; 2650 defobj = obj; 2651 } 2652 } 2653 2654 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 2655 STAILQ_FOREACH(elm, &list_global, link) { 2656 if (def != NULL && ELF_ST_BIND(def->st_info) != STB_WEAK) 2657 break; 2658 symp = symlook_list(name, hash, &elm->obj->dagmembers, &obj, ventry, 2659 flags, &donelist); 2660 if (symp != NULL && 2661 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { 2662 def = symp; 2663 defobj = obj; 2664 } 2665 } 2666 2667 /* Search all dlopened DAGs containing the referencing object. */ 2668 STAILQ_FOREACH(elm, &refobj->dldags, link) { 2669 if (def != NULL && ELF_ST_BIND(def->st_info) != STB_WEAK) 2670 break; 2671 symp = symlook_list(name, hash, &elm->obj->dagmembers, &obj, ventry, 2672 flags, &donelist); 2673 if (symp != NULL && 2674 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { 2675 def = symp; 2676 defobj = obj; 2677 } 2678 } 2679 2680 /* 2681 * Search the dynamic linker itself, and possibly resolve the 2682 * symbol from there. This is how the application links to 2683 * dynamic linker services such as dlopen. Only the values listed 2684 * in the "exports" array can be resolved from the dynamic linker. 2685 */ 2686 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2687 symp = symlook_obj(name, hash, &obj_rtld, ventry, flags); 2688 if (symp != NULL && is_exported(symp)) { 2689 def = symp; 2690 defobj = &obj_rtld; 2691 } 2692 } 2693 2694 if (def != NULL) 2695 *defobj_out = defobj; 2696 return def; 2697} 2698 2699static const Elf_Sym * 2700symlook_list(const char *name, unsigned long hash, const Objlist *objlist, 2701 const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags, 2702 DoneList *dlp) 2703{ 2704 const Elf_Sym *symp; 2705 const Elf_Sym *def; 2706 const Obj_Entry *defobj; 2707 const Objlist_Entry *elm; 2708 2709 def = NULL; 2710 defobj = NULL; 2711 STAILQ_FOREACH(elm, objlist, link) { 2712 if (donelist_check(dlp, elm->obj)) 2713 continue; 2714 if ((symp = symlook_obj(name, hash, elm->obj, ventry, flags)) != NULL) { 2715 if (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK) { 2716 def = symp; 2717 defobj = elm->obj; 2718 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 2719 break; 2720 } 2721 } 2722 } 2723 if (def != NULL) 2724 *defobj_out = defobj; 2725 return def; 2726} 2727 2728/* 2729 * Search the symbol table of a shared object and all objects needed 2730 * by it for a symbol of the given name. Search order is 2731 * breadth-first. Returns a pointer to the symbol, or NULL if no 2732 * definition was found. 2733 */ 2734static const Elf_Sym * 2735symlook_needed(const char *name, unsigned long hash, const Needed_Entry *needed, 2736 const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags, 2737 DoneList *dlp) 2738{ 2739 const Elf_Sym *def, *def_w; 2740 const Needed_Entry *n; 2741 const Obj_Entry *obj, *defobj, *defobj1; 2742 2743 def = def_w = NULL; 2744 defobj = NULL; 2745 for (n = needed; n != NULL; n = n->next) { 2746 if ((obj = n->obj) == NULL || 2747 donelist_check(dlp, obj) || 2748 (def = symlook_obj(name, hash, obj, ventry, flags)) == NULL) 2749 continue; 2750 defobj = obj; 2751 if (ELF_ST_BIND(def->st_info) != STB_WEAK) { 2752 *defobj_out = defobj; 2753 return (def); 2754 } 2755 } 2756 /* 2757 * There we come when either symbol definition is not found in 2758 * directly needed objects, or found symbol is weak. 2759 */ 2760 for (n = needed; n != NULL; n = n->next) { 2761 if ((obj = n->obj) == NULL) 2762 continue; 2763 def_w = symlook_needed(name, hash, obj->needed, &defobj1, 2764 ventry, flags, dlp); 2765 if (def_w == NULL) 2766 continue; 2767 if (def == NULL || ELF_ST_BIND(def_w->st_info) != STB_WEAK) { 2768 def = def_w; 2769 defobj = defobj1; 2770 } 2771 if (ELF_ST_BIND(def_w->st_info) != STB_WEAK) 2772 break; 2773 } 2774 if (def != NULL) 2775 *defobj_out = defobj; 2776 return (def); 2777} 2778 2779/* 2780 * Search the symbol table of a single shared object for a symbol of 2781 * the given name and version, if requested. Returns a pointer to the 2782 * symbol, or NULL if no definition was found. 2783 * 2784 * The symbol's hash value is passed in for efficiency reasons; that 2785 * eliminates many recomputations of the hash value. 2786 */ 2787const Elf_Sym * 2788symlook_obj(const char *name, unsigned long hash, const Obj_Entry *obj, 2789 const Ver_Entry *ventry, int flags) 2790{ 2791 unsigned long symnum; 2792 const Elf_Sym *vsymp; 2793 Elf_Versym verndx; 2794 int vcount; 2795 2796 if (obj->buckets == NULL) 2797 return NULL; 2798 2799 vsymp = NULL; 2800 vcount = 0; 2801 symnum = obj->buckets[hash % obj->nbuckets]; 2802 2803 for (; symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 2804 const Elf_Sym *symp; 2805 const char *strp; 2806 2807 if (symnum >= obj->nchains) 2808 return NULL; /* Bad object */ 2809 2810 symp = obj->symtab + symnum; 2811 strp = obj->strtab + symp->st_name; 2812 2813 switch (ELF_ST_TYPE(symp->st_info)) { 2814 case STT_FUNC: 2815 case STT_NOTYPE: 2816 case STT_OBJECT: 2817 if (symp->st_value == 0) 2818 continue; 2819 /* fallthrough */ 2820 case STT_TLS: 2821 if (symp->st_shndx != SHN_UNDEF) 2822 break; 2823#ifndef __mips__ 2824 else if (((flags & SYMLOOK_IN_PLT) == 0) && 2825 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 2826 break; 2827 /* fallthrough */ 2828#endif 2829 default: 2830 continue; 2831 } 2832 if (name[0] != strp[0] || strcmp(name, strp) != 0) 2833 continue; 2834 2835 if (ventry == NULL) { 2836 if (obj->versyms != NULL) { 2837 verndx = VER_NDX(obj->versyms[symnum]); 2838 if (verndx > obj->vernum) { 2839 _rtld_error("%s: symbol %s references wrong version %d", 2840 obj->path, obj->strtab + symnum, verndx); 2841 continue; 2842 } 2843 /* 2844 * If we are not called from dlsym (i.e. this is a normal 2845 * relocation from unversioned binary, accept the symbol 2846 * immediately if it happens to have first version after 2847 * this shared object became versioned. Otherwise, if 2848 * symbol is versioned and not hidden, remember it. If it 2849 * is the only symbol with this name exported by the 2850 * shared object, it will be returned as a match at the 2851 * end of the function. If symbol is global (verndx < 2) 2852 * accept it unconditionally. 2853 */ 2854 if ((flags & SYMLOOK_DLSYM) == 0 && verndx == VER_NDX_GIVEN) 2855 return symp; 2856 else if (verndx >= VER_NDX_GIVEN) { 2857 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) == 0) { 2858 if (vsymp == NULL) 2859 vsymp = symp; 2860 vcount ++; 2861 } 2862 continue; 2863 } 2864 } 2865 return symp; 2866 } else { 2867 if (obj->versyms == NULL) { 2868 if (object_match_name(obj, ventry->name)) { 2869 _rtld_error("%s: object %s should provide version %s for " 2870 "symbol %s", obj_rtld.path, obj->path, ventry->name, 2871 obj->strtab + symnum); 2872 continue; 2873 } 2874 } else { 2875 verndx = VER_NDX(obj->versyms[symnum]); 2876 if (verndx > obj->vernum) { 2877 _rtld_error("%s: symbol %s references wrong version %d", 2878 obj->path, obj->strtab + symnum, verndx); 2879 continue; 2880 } 2881 if (obj->vertab[verndx].hash != ventry->hash || 2882 strcmp(obj->vertab[verndx].name, ventry->name)) { 2883 /* 2884 * Version does not match. Look if this is a global symbol 2885 * and if it is not hidden. If global symbol (verndx < 2) 2886 * is available, use it. Do not return symbol if we are 2887 * called by dlvsym, because dlvsym looks for a specific 2888 * version and default one is not what dlvsym wants. 2889 */ 2890 if ((flags & SYMLOOK_DLSYM) || 2891 (obj->versyms[symnum] & VER_NDX_HIDDEN) || 2892 (verndx >= VER_NDX_GIVEN)) 2893 continue; 2894 } 2895 } 2896 return symp; 2897 } 2898 } 2899 return (vcount == 1) ? vsymp : NULL; 2900} 2901 2902static void 2903trace_loaded_objects(Obj_Entry *obj) 2904{ 2905 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 2906 int c; 2907 2908 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 2909 main_local = ""; 2910 2911 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL) 2912 fmt1 = "\t%o => %p (%x)\n"; 2913 2914 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL) 2915 fmt2 = "\t%o (%x)\n"; 2916 2917 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL"); 2918 2919 for (; obj; obj = obj->next) { 2920 Needed_Entry *needed; 2921 char *name, *path; 2922 bool is_lib; 2923 2924 if (list_containers && obj->needed != NULL) 2925 printf("%s:\n", obj->path); 2926 for (needed = obj->needed; needed; needed = needed->next) { 2927 if (needed->obj != NULL) { 2928 if (needed->obj->traced && !list_containers) 2929 continue; 2930 needed->obj->traced = true; 2931 path = needed->obj->path; 2932 } else 2933 path = "not found"; 2934 2935 name = (char *)obj->strtab + needed->name; 2936 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 2937 2938 fmt = is_lib ? fmt1 : fmt2; 2939 while ((c = *fmt++) != '\0') { 2940 switch (c) { 2941 default: 2942 putchar(c); 2943 continue; 2944 case '\\': 2945 switch (c = *fmt) { 2946 case '\0': 2947 continue; 2948 case 'n': 2949 putchar('\n'); 2950 break; 2951 case 't': 2952 putchar('\t'); 2953 break; 2954 } 2955 break; 2956 case '%': 2957 switch (c = *fmt) { 2958 case '\0': 2959 continue; 2960 case '%': 2961 default: 2962 putchar(c); 2963 break; 2964 case 'A': 2965 printf("%s", main_local); 2966 break; 2967 case 'a': 2968 printf("%s", obj_main->path); 2969 break; 2970 case 'o': 2971 printf("%s", name); 2972 break; 2973#if 0 2974 case 'm': 2975 printf("%d", sodp->sod_major); 2976 break; 2977 case 'n': 2978 printf("%d", sodp->sod_minor); 2979 break; 2980#endif 2981 case 'p': 2982 printf("%s", path); 2983 break; 2984 case 'x': 2985 printf("%p", needed->obj ? needed->obj->mapbase : 0); 2986 break; 2987 } 2988 break; 2989 } 2990 ++fmt; 2991 } 2992 } 2993 } 2994} 2995 2996/* 2997 * Unload a dlopened object and its dependencies from memory and from 2998 * our data structures. It is assumed that the DAG rooted in the 2999 * object has already been unreferenced, and that the object has a 3000 * reference count of 0. 3001 */ 3002static void 3003unload_object(Obj_Entry *root) 3004{ 3005 Obj_Entry *obj; 3006 Obj_Entry **linkp; 3007 3008 assert(root->refcount == 0); 3009 3010 /* 3011 * Pass over the DAG removing unreferenced objects from 3012 * appropriate lists. 3013 */ 3014 unlink_object(root); 3015 3016 /* Unmap all objects that are no longer referenced. */ 3017 linkp = &obj_list->next; 3018 while ((obj = *linkp) != NULL) { 3019 if (obj->refcount == 0) { 3020 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 3021 obj->path); 3022 dbg("unloading \"%s\"", obj->path); 3023 munmap(obj->mapbase, obj->mapsize); 3024 linkmap_delete(obj); 3025 *linkp = obj->next; 3026 obj_count--; 3027 obj_free(obj); 3028 } else 3029 linkp = &obj->next; 3030 } 3031 obj_tail = linkp; 3032} 3033 3034static void 3035unlink_object(Obj_Entry *root) 3036{ 3037 Objlist_Entry *elm; 3038 3039 if (root->refcount == 0) { 3040 /* Remove the object from the RTLD_GLOBAL list. */ 3041 objlist_remove(&list_global, root); 3042 3043 /* Remove the object from all objects' DAG lists. */ 3044 STAILQ_FOREACH(elm, &root->dagmembers, link) { 3045 objlist_remove(&elm->obj->dldags, root); 3046 if (elm->obj != root) 3047 unlink_object(elm->obj); 3048 } 3049 } 3050} 3051 3052static void 3053ref_dag(Obj_Entry *root) 3054{ 3055 Objlist_Entry *elm; 3056 3057 STAILQ_FOREACH(elm, &root->dagmembers, link) 3058 elm->obj->refcount++; 3059} 3060 3061static void 3062unref_dag(Obj_Entry *root) 3063{ 3064 Objlist_Entry *elm; 3065 3066 STAILQ_FOREACH(elm, &root->dagmembers, link) 3067 elm->obj->refcount--; 3068} 3069 3070/* 3071 * Common code for MD __tls_get_addr(). 3072 */ 3073void * 3074tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset) 3075{ 3076 Elf_Addr* dtv = *dtvp; 3077 int lockstate; 3078 3079 /* Check dtv generation in case new modules have arrived */ 3080 if (dtv[0] != tls_dtv_generation) { 3081 Elf_Addr* newdtv; 3082 int to_copy; 3083 3084 lockstate = wlock_acquire(rtld_bind_lock); 3085 newdtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr)); 3086 to_copy = dtv[1]; 3087 if (to_copy > tls_max_index) 3088 to_copy = tls_max_index; 3089 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 3090 newdtv[0] = tls_dtv_generation; 3091 newdtv[1] = tls_max_index; 3092 free(dtv); 3093 wlock_release(rtld_bind_lock, lockstate); 3094 *dtvp = newdtv; 3095 } 3096 3097 /* Dynamically allocate module TLS if necessary */ 3098 if (!dtv[index + 1]) { 3099 /* Signal safe, wlock will block out signals. */ 3100 lockstate = wlock_acquire(rtld_bind_lock); 3101 if (!dtv[index + 1]) 3102 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 3103 wlock_release(rtld_bind_lock, lockstate); 3104 } 3105 return (void*) (dtv[index + 1] + offset); 3106} 3107 3108/* XXX not sure what variants to use for arm. */ 3109 3110#if defined(__ia64__) || defined(__powerpc__) 3111 3112/* 3113 * Allocate Static TLS using the Variant I method. 3114 */ 3115void * 3116allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 3117{ 3118 Obj_Entry *obj; 3119 char *tcb; 3120 Elf_Addr **tls; 3121 Elf_Addr *dtv; 3122 Elf_Addr addr; 3123 int i; 3124 3125 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 3126 return (oldtcb); 3127 3128 assert(tcbsize >= TLS_TCB_SIZE); 3129 tcb = calloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 3130 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 3131 3132 if (oldtcb != NULL) { 3133 memcpy(tls, oldtcb, tls_static_space); 3134 free(oldtcb); 3135 3136 /* Adjust the DTV. */ 3137 dtv = tls[0]; 3138 for (i = 0; i < dtv[1]; i++) { 3139 if (dtv[i+2] >= (Elf_Addr)oldtcb && 3140 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 3141 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 3142 } 3143 } 3144 } else { 3145 dtv = calloc(tls_max_index + 2, sizeof(Elf_Addr)); 3146 tls[0] = dtv; 3147 dtv[0] = tls_dtv_generation; 3148 dtv[1] = tls_max_index; 3149 3150 for (obj = objs; obj; obj = obj->next) { 3151 if (obj->tlsoffset) { 3152 addr = (Elf_Addr)tls + obj->tlsoffset; 3153 memset((void*) (addr + obj->tlsinitsize), 3154 0, obj->tlssize - obj->tlsinitsize); 3155 if (obj->tlsinit) 3156 memcpy((void*) addr, obj->tlsinit, 3157 obj->tlsinitsize); 3158 dtv[obj->tlsindex + 1] = addr; 3159 } 3160 } 3161 } 3162 3163 return (tcb); 3164} 3165 3166void 3167free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 3168{ 3169 Elf_Addr *dtv; 3170 Elf_Addr tlsstart, tlsend; 3171 int dtvsize, i; 3172 3173 assert(tcbsize >= TLS_TCB_SIZE); 3174 3175 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 3176 tlsend = tlsstart + tls_static_space; 3177 3178 dtv = *(Elf_Addr **)tlsstart; 3179 dtvsize = dtv[1]; 3180 for (i = 0; i < dtvsize; i++) { 3181 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 3182 free((void*)dtv[i+2]); 3183 } 3184 } 3185 free(dtv); 3186 free(tcb); 3187} 3188 3189#endif 3190 3191#if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) || \ 3192 defined(__arm__) || defined(__mips__) 3193 3194/* 3195 * Allocate Static TLS using the Variant II method. 3196 */ 3197void * 3198allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 3199{ 3200 Obj_Entry *obj; 3201 size_t size; 3202 char *tls; 3203 Elf_Addr *dtv, *olddtv; 3204 Elf_Addr segbase, oldsegbase, addr; 3205 int i; 3206 3207 size = round(tls_static_space, tcbalign); 3208 3209 assert(tcbsize >= 2*sizeof(Elf_Addr)); 3210 tls = calloc(1, size + tcbsize); 3211 dtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr)); 3212 3213 segbase = (Elf_Addr)(tls + size); 3214 ((Elf_Addr*)segbase)[0] = segbase; 3215 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 3216 3217 dtv[0] = tls_dtv_generation; 3218 dtv[1] = tls_max_index; 3219 3220 if (oldtls) { 3221 /* 3222 * Copy the static TLS block over whole. 3223 */ 3224 oldsegbase = (Elf_Addr) oldtls; 3225 memcpy((void *)(segbase - tls_static_space), 3226 (const void *)(oldsegbase - tls_static_space), 3227 tls_static_space); 3228 3229 /* 3230 * If any dynamic TLS blocks have been created tls_get_addr(), 3231 * move them over. 3232 */ 3233 olddtv = ((Elf_Addr**)oldsegbase)[1]; 3234 for (i = 0; i < olddtv[1]; i++) { 3235 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 3236 dtv[i+2] = olddtv[i+2]; 3237 olddtv[i+2] = 0; 3238 } 3239 } 3240 3241 /* 3242 * We assume that this block was the one we created with 3243 * allocate_initial_tls(). 3244 */ 3245 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 3246 } else { 3247 for (obj = objs; obj; obj = obj->next) { 3248 if (obj->tlsoffset) { 3249 addr = segbase - obj->tlsoffset; 3250 memset((void*) (addr + obj->tlsinitsize), 3251 0, obj->tlssize - obj->tlsinitsize); 3252 if (obj->tlsinit) 3253 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 3254 dtv[obj->tlsindex + 1] = addr; 3255 } 3256 } 3257 } 3258 3259 return (void*) segbase; 3260} 3261 3262void 3263free_tls(void *tls, size_t tcbsize, size_t tcbalign) 3264{ 3265 size_t size; 3266 Elf_Addr* dtv; 3267 int dtvsize, i; 3268 Elf_Addr tlsstart, tlsend; 3269 3270 /* 3271 * Figure out the size of the initial TLS block so that we can 3272 * find stuff which ___tls_get_addr() allocated dynamically. 3273 */ 3274 size = round(tls_static_space, tcbalign); 3275 3276 dtv = ((Elf_Addr**)tls)[1]; 3277 dtvsize = dtv[1]; 3278 tlsend = (Elf_Addr) tls; 3279 tlsstart = tlsend - size; 3280 for (i = 0; i < dtvsize; i++) { 3281 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] > tlsend)) { 3282 free((void*) dtv[i+2]); 3283 } 3284 } 3285 3286 free((void*) tlsstart); 3287 free((void*) dtv); 3288} 3289 3290#endif 3291 3292/* 3293 * Allocate TLS block for module with given index. 3294 */ 3295void * 3296allocate_module_tls(int index) 3297{ 3298 Obj_Entry* obj; 3299 char* p; 3300 3301 for (obj = obj_list; obj; obj = obj->next) { 3302 if (obj->tlsindex == index) 3303 break; 3304 } 3305 if (!obj) { 3306 _rtld_error("Can't find module with TLS index %d", index); 3307 die(); 3308 } 3309 3310 p = malloc(obj->tlssize); 3311 memcpy(p, obj->tlsinit, obj->tlsinitsize); 3312 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 3313 3314 return p; 3315} 3316 3317bool 3318allocate_tls_offset(Obj_Entry *obj) 3319{ 3320 size_t off; 3321 3322 if (obj->tls_done) 3323 return true; 3324 3325 if (obj->tlssize == 0) { 3326 obj->tls_done = true; 3327 return true; 3328 } 3329 3330 if (obj->tlsindex == 1) 3331 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 3332 else 3333 off = calculate_tls_offset(tls_last_offset, tls_last_size, 3334 obj->tlssize, obj->tlsalign); 3335 3336 /* 3337 * If we have already fixed the size of the static TLS block, we 3338 * must stay within that size. When allocating the static TLS, we 3339 * leave a small amount of space spare to be used for dynamically 3340 * loading modules which use static TLS. 3341 */ 3342 if (tls_static_space) { 3343 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 3344 return false; 3345 } 3346 3347 tls_last_offset = obj->tlsoffset = off; 3348 tls_last_size = obj->tlssize; 3349 obj->tls_done = true; 3350 3351 return true; 3352} 3353 3354void 3355free_tls_offset(Obj_Entry *obj) 3356{ 3357#if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) || \ 3358 defined(__arm__) || defined(__mips__) 3359 /* 3360 * If we were the last thing to allocate out of the static TLS 3361 * block, we give our space back to the 'allocator'. This is a 3362 * simplistic workaround to allow libGL.so.1 to be loaded and 3363 * unloaded multiple times. We only handle the Variant II 3364 * mechanism for now - this really needs a proper allocator. 3365 */ 3366 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 3367 == calculate_tls_end(tls_last_offset, tls_last_size)) { 3368 tls_last_offset -= obj->tlssize; 3369 tls_last_size = 0; 3370 } 3371#endif 3372} 3373 3374void * 3375_rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 3376{ 3377 void *ret; 3378 int lockstate; 3379 3380 lockstate = wlock_acquire(rtld_bind_lock); 3381 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign); 3382 wlock_release(rtld_bind_lock, lockstate); 3383 return (ret); 3384} 3385 3386void 3387_rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 3388{ 3389 int lockstate; 3390 3391 lockstate = wlock_acquire(rtld_bind_lock); 3392 free_tls(tcb, tcbsize, tcbalign); 3393 wlock_release(rtld_bind_lock, lockstate); 3394} 3395 3396static void 3397object_add_name(Obj_Entry *obj, const char *name) 3398{ 3399 Name_Entry *entry; 3400 size_t len; 3401 3402 len = strlen(name); 3403 entry = malloc(sizeof(Name_Entry) + len); 3404 3405 if (entry != NULL) { 3406 strcpy(entry->name, name); 3407 STAILQ_INSERT_TAIL(&obj->names, entry, link); 3408 } 3409} 3410 3411static int 3412object_match_name(const Obj_Entry *obj, const char *name) 3413{ 3414 Name_Entry *entry; 3415 3416 STAILQ_FOREACH(entry, &obj->names, link) { 3417 if (strcmp(name, entry->name) == 0) 3418 return (1); 3419 } 3420 return (0); 3421} 3422 3423static Obj_Entry * 3424locate_dependency(const Obj_Entry *obj, const char *name) 3425{ 3426 const Objlist_Entry *entry; 3427 const Needed_Entry *needed; 3428 3429 STAILQ_FOREACH(entry, &list_main, link) { 3430 if (object_match_name(entry->obj, name)) 3431 return entry->obj; 3432 } 3433 3434 for (needed = obj->needed; needed != NULL; needed = needed->next) { 3435 if (needed->obj == NULL) 3436 continue; 3437 if (object_match_name(needed->obj, name)) 3438 return needed->obj; 3439 } 3440 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 3441 obj->path, name); 3442 die(); 3443} 3444 3445static int 3446check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 3447 const Elf_Vernaux *vna) 3448{ 3449 const Elf_Verdef *vd; 3450 const char *vername; 3451 3452 vername = refobj->strtab + vna->vna_name; 3453 vd = depobj->verdef; 3454 if (vd == NULL) { 3455 _rtld_error("%s: version %s required by %s not defined", 3456 depobj->path, vername, refobj->path); 3457 return (-1); 3458 } 3459 for (;;) { 3460 if (vd->vd_version != VER_DEF_CURRENT) { 3461 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 3462 depobj->path, vd->vd_version); 3463 return (-1); 3464 } 3465 if (vna->vna_hash == vd->vd_hash) { 3466 const Elf_Verdaux *aux = (const Elf_Verdaux *) 3467 ((char *)vd + vd->vd_aux); 3468 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 3469 return (0); 3470 } 3471 if (vd->vd_next == 0) 3472 break; 3473 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3474 } 3475 if (vna->vna_flags & VER_FLG_WEAK) 3476 return (0); 3477 _rtld_error("%s: version %s required by %s not found", 3478 depobj->path, vername, refobj->path); 3479 return (-1); 3480} 3481 3482static int 3483rtld_verify_object_versions(Obj_Entry *obj) 3484{ 3485 const Elf_Verneed *vn; 3486 const Elf_Verdef *vd; 3487 const Elf_Verdaux *vda; 3488 const Elf_Vernaux *vna; 3489 const Obj_Entry *depobj; 3490 int maxvernum, vernum; 3491 3492 maxvernum = 0; 3493 /* 3494 * Walk over defined and required version records and figure out 3495 * max index used by any of them. Do very basic sanity checking 3496 * while there. 3497 */ 3498 vn = obj->verneed; 3499 while (vn != NULL) { 3500 if (vn->vn_version != VER_NEED_CURRENT) { 3501 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 3502 obj->path, vn->vn_version); 3503 return (-1); 3504 } 3505 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 3506 for (;;) { 3507 vernum = VER_NEED_IDX(vna->vna_other); 3508 if (vernum > maxvernum) 3509 maxvernum = vernum; 3510 if (vna->vna_next == 0) 3511 break; 3512 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 3513 } 3514 if (vn->vn_next == 0) 3515 break; 3516 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 3517 } 3518 3519 vd = obj->verdef; 3520 while (vd != NULL) { 3521 if (vd->vd_version != VER_DEF_CURRENT) { 3522 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 3523 obj->path, vd->vd_version); 3524 return (-1); 3525 } 3526 vernum = VER_DEF_IDX(vd->vd_ndx); 3527 if (vernum > maxvernum) 3528 maxvernum = vernum; 3529 if (vd->vd_next == 0) 3530 break; 3531 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3532 } 3533 3534 if (maxvernum == 0) 3535 return (0); 3536 3537 /* 3538 * Store version information in array indexable by version index. 3539 * Verify that object version requirements are satisfied along the 3540 * way. 3541 */ 3542 obj->vernum = maxvernum + 1; 3543 obj->vertab = calloc(obj->vernum, sizeof(Ver_Entry)); 3544 3545 vd = obj->verdef; 3546 while (vd != NULL) { 3547 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 3548 vernum = VER_DEF_IDX(vd->vd_ndx); 3549 assert(vernum <= maxvernum); 3550 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 3551 obj->vertab[vernum].hash = vd->vd_hash; 3552 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 3553 obj->vertab[vernum].file = NULL; 3554 obj->vertab[vernum].flags = 0; 3555 } 3556 if (vd->vd_next == 0) 3557 break; 3558 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3559 } 3560 3561 vn = obj->verneed; 3562 while (vn != NULL) { 3563 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 3564 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 3565 for (;;) { 3566 if (check_object_provided_version(obj, depobj, vna)) 3567 return (-1); 3568 vernum = VER_NEED_IDX(vna->vna_other); 3569 assert(vernum <= maxvernum); 3570 obj->vertab[vernum].hash = vna->vna_hash; 3571 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 3572 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 3573 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 3574 VER_INFO_HIDDEN : 0; 3575 if (vna->vna_next == 0) 3576 break; 3577 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 3578 } 3579 if (vn->vn_next == 0) 3580 break; 3581 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 3582 } 3583 return 0; 3584} 3585 3586static int 3587rtld_verify_versions(const Objlist *objlist) 3588{ 3589 Objlist_Entry *entry; 3590 int rc; 3591 3592 rc = 0; 3593 STAILQ_FOREACH(entry, objlist, link) { 3594 /* 3595 * Skip dummy objects or objects that have their version requirements 3596 * already checked. 3597 */ 3598 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 3599 continue; 3600 if (rtld_verify_object_versions(entry->obj) == -1) { 3601 rc = -1; 3602 if (ld_tracing == NULL) 3603 break; 3604 } 3605 } 3606 if (rc == 0 || ld_tracing != NULL) 3607 rc = rtld_verify_object_versions(&obj_rtld); 3608 return rc; 3609} 3610 3611const Ver_Entry * 3612fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 3613{ 3614 Elf_Versym vernum; 3615 3616 if (obj->vertab) { 3617 vernum = VER_NDX(obj->versyms[symnum]); 3618 if (vernum >= obj->vernum) { 3619 _rtld_error("%s: symbol %s has wrong verneed value %d", 3620 obj->path, obj->strtab + symnum, vernum); 3621 } else if (obj->vertab[vernum].hash != 0) { 3622 return &obj->vertab[vernum]; 3623 } 3624 } 3625 return NULL; 3626} 3627