1 /* $NetBSD: rtld.c,v 1.169 2013/05/09 15:47:34 skrll Exp $ */ 2 3 /* 4 * Copyright 1996 John D. Polstra. 5 * Copyright 1996 Matt Thomas <matt@3am-software.com> 6 * Copyright 2002 Charles M. Hannum <root@ihack.net> 7 * All rights reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. All advertising materials mentioning features or use of this software 18 * must display the following acknowledgement: 19 * This product includes software developed by John Polstra. 20 * 4. The name of the author may not be used to endorse or promote products 21 * derived from this software without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 25 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 26 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 27 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 28 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 29 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 30 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 31 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 32 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 33 */ 34 35 /* 36 * Dynamic linker for ELF. 37 * 38 * John Polstra <jdp@polstra.com>. 39 */ 40 41 #include <sys/cdefs.h> 42 #ifndef lint 43 __RCSID("$NetBSD: rtld.c,v 1.169 2013/05/09 15:47:34 skrll Exp $"); 44 #endif /* not lint */ 45 46 #include <sys/param.h> 47 #include <sys/atomic.h> 48 #include <sys/mman.h> 49 #include <err.h> 50 #include <errno.h> 51 #include <fcntl.h> 52 #include <lwp.h> 53 #include <stdarg.h> 54 #include <stdio.h> 55 #include <stdlib.h> 56 #include <string.h> 57 #include <unistd.h> 58 #include <dirent.h> 59 60 #include <ctype.h> 61 62 #include <dlfcn.h> 63 #include "debug.h" 64 #include "rtld.h" 65 66 #if !defined(lint) 67 #include "sysident.h" 68 #endif 69 70 /* 71 * Function declarations. 72 */ 73 static void _rtld_init(caddr_t, caddr_t, const char *); 74 static void _rtld_exit(void); 75 76 Elf_Addr _rtld(Elf_Addr *, Elf_Addr); 77 78 79 /* 80 * Data declarations. 81 */ 82 static char *error_message; /* Message for dlopen(), or NULL */ 83 84 struct r_debug _rtld_debug; /* for GDB; */ 85 bool _rtld_trust; /* False for setuid and setgid programs */ 86 Obj_Entry *_rtld_objlist; /* Head of linked list of shared objects */ 87 Obj_Entry **_rtld_objtail; /* Link field of last object in list */ 88 Obj_Entry *_rtld_objmain; /* The main program shared object */ 89 Obj_Entry _rtld_objself; /* The dynamic linker shared object */ 90 u_int _rtld_objcount; /* Number of objects in _rtld_objlist */ 91 u_int _rtld_objloads; /* Number of objects loaded in _rtld_objlist */ 92 u_int _rtld_objgen; /* Generation count for _rtld_objlist */ 93 const char _rtld_path[] = _PATH_RTLD; 94 95 /* Initialize a fake symbol for resolving undefined weak references. */ 96 Elf_Sym _rtld_sym_zero = { 97 .st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE), 98 .st_shndx = SHN_ABS, 99 }; 100 size_t _rtld_pagesz; /* Page size, as provided by kernel */ 101 102 Search_Path *_rtld_default_paths; 103 Search_Path *_rtld_paths; 104 105 Library_Xform *_rtld_xforms; 106 static void *auxinfo; 107 108 /* 109 * Global declarations normally provided by crt0. 110 */ 111 char *__progname; 112 char **environ; 113 114 static volatile bool _rtld_mutex_may_recurse; 115 116 #if defined(RTLD_DEBUG) 117 #ifndef __sh__ 118 extern Elf_Addr _GLOBAL_OFFSET_TABLE_[]; 119 #else /* 32-bit SuperH */ 120 register Elf_Addr *_GLOBAL_OFFSET_TABLE_ asm("r12"); 121 #endif 122 #endif /* RTLD_DEBUG */ 123 extern Elf_Dyn _DYNAMIC; 124 125 static void _rtld_call_fini_functions(sigset_t *, int); 126 static void _rtld_call_init_functions(sigset_t *); 127 static void _rtld_initlist_visit(Objlist *, Obj_Entry *, int); 128 static void _rtld_initlist_tsort(Objlist *, int); 129 static Obj_Entry *_rtld_dlcheck(void *); 130 static void _rtld_init_dag(Obj_Entry *); 131 static void _rtld_init_dag1(Obj_Entry *, Obj_Entry *); 132 static void _rtld_objlist_remove(Objlist *, Obj_Entry *); 133 static void _rtld_objlist_clear(Objlist *); 134 static void _rtld_unload_object(sigset_t *, Obj_Entry *, bool); 135 static void _rtld_unref_dag(Obj_Entry *); 136 static Obj_Entry *_rtld_obj_from_addr(const void *); 137 138 static inline void 139 _rtld_call_initfini_function(fptr_t func, sigset_t *mask) 140 { 141 _rtld_exclusive_exit(mask); 142 (*func)(); 143 _rtld_exclusive_enter(mask); 144 } 145 146 static void 147 _rtld_call_fini_function(Obj_Entry *obj, sigset_t *mask, u_int cur_objgen) 148 { 149 if (obj->fini_arraysz == 0 && (obj->fini == NULL || obj->fini_called)) { 150 return; 151 } 152 if (obj->fini != NULL && !obj->fini_called) { 153 dbg (("calling fini function %s at %p%s", obj->path, 154 (void *)obj->fini, 155 obj->z_initfirst ? " (DF_1_INITFIRST)" : "")); 156 obj->fini_called = 1; 157 _rtld_call_initfini_function(obj->fini, mask); 158 } 159 #ifdef HAVE_INITFINI_ARRAY 160 /* 161 * Now process the fini_array if it exists. Simply go from 162 * start to end. We need to make restartable so just advance 163 * the array pointer and decrement the size each time through 164 * the loop. 165 */ 166 while (obj->fini_arraysz > 0 && _rtld_objgen == cur_objgen) { 167 fptr_t fini = *obj->fini_array++; 168 obj->fini_arraysz--; 169 dbg (("calling fini array function %s at %p%s", obj->path, 170 (void *)fini, 171 obj->z_initfirst ? " (DF_1_INITFIRST)" : "")); 172 _rtld_call_initfini_function(fini, mask); 173 } 174 #endif /* HAVE_INITFINI_ARRAY */ 175 } 176 177 static void 178 _rtld_call_fini_functions(sigset_t *mask, int force) 179 { 180 Objlist_Entry *elm; 181 Objlist finilist; 182 u_int cur_objgen; 183 184 dbg(("_rtld_call_fini_functions(%d)", force)); 185 186 restart: 187 cur_objgen = ++_rtld_objgen; 188 SIMPLEQ_INIT(&finilist); 189 _rtld_initlist_tsort(&finilist, 1); 190 191 /* First pass: objects _not_ marked with DF_1_INITFIRST. */ 192 SIMPLEQ_FOREACH(elm, &finilist, link) { 193 Obj_Entry * const obj = elm->obj; 194 if (!obj->z_initfirst) { 195 if (obj->refcount > 0 && !force) { 196 continue; 197 } 198 /* 199 * XXX This can race against a concurrent dlclose(). 200 * XXX In that case, the object could be unmapped before 201 * XXX the fini() call or the fini_array has completed. 202 */ 203 _rtld_call_fini_function(obj, mask, cur_objgen); 204 if (_rtld_objgen != cur_objgen) { 205 dbg(("restarting fini iteration")); 206 _rtld_objlist_clear(&finilist); 207 goto restart; 208 } 209 } 210 } 211 212 /* Second pass: objects marked with DF_1_INITFIRST. */ 213 SIMPLEQ_FOREACH(elm, &finilist, link) { 214 Obj_Entry * const obj = elm->obj; 215 if (obj->refcount > 0 && !force) { 216 continue; 217 } 218 /* XXX See above for the race condition here */ 219 _rtld_call_fini_function(obj, mask, cur_objgen); 220 if (_rtld_objgen != cur_objgen) { 221 dbg(("restarting fini iteration")); 222 _rtld_objlist_clear(&finilist); 223 goto restart; 224 } 225 } 226 227 _rtld_objlist_clear(&finilist); 228 } 229 230 static void 231 _rtld_call_init_function(Obj_Entry *obj, sigset_t *mask, u_int cur_objgen) 232 { 233 if (obj->init_arraysz == 0 && (obj->init_called || obj->init == NULL)) { 234 return; 235 } 236 if (!obj->init_called && obj->init != NULL) { 237 dbg (("calling init function %s at %p%s", 238 obj->path, (void *)obj->init, 239 obj->z_initfirst ? " (DF_1_INITFIRST)" : "")); 240 obj->init_called = 1; 241 _rtld_call_initfini_function(obj->init, mask); 242 } 243 244 #ifdef HAVE_INITFINI_ARRAY 245 /* 246 * Now process the init_array if it exists. Simply go from 247 * start to end. We need to make restartable so just advance 248 * the array pointer and decrement the size each time through 249 * the loop. 250 */ 251 while (obj->init_arraysz > 0 && _rtld_objgen == cur_objgen) { 252 fptr_t init = *obj->init_array++; 253 obj->init_arraysz--; 254 dbg (("calling init_array function %s at %p%s", 255 obj->path, (void *)init, 256 obj->z_initfirst ? " (DF_1_INITFIRST)" : "")); 257 _rtld_call_initfini_function(init, mask); 258 } 259 #endif /* HAVE_INITFINI_ARRAY */ 260 } 261 262 static void 263 _rtld_call_init_functions(sigset_t *mask) 264 { 265 Objlist_Entry *elm; 266 Objlist initlist; 267 u_int cur_objgen; 268 269 dbg(("_rtld_call_init_functions()")); 270 271 restart: 272 cur_objgen = ++_rtld_objgen; 273 SIMPLEQ_INIT(&initlist); 274 _rtld_initlist_tsort(&initlist, 0); 275 276 /* First pass: objects marked with DF_1_INITFIRST. */ 277 SIMPLEQ_FOREACH(elm, &initlist, link) { 278 Obj_Entry * const obj = elm->obj; 279 if (obj->z_initfirst) { 280 _rtld_call_init_function(obj, mask, cur_objgen); 281 if (_rtld_objgen != cur_objgen) { 282 dbg(("restarting init iteration")); 283 _rtld_objlist_clear(&initlist); 284 goto restart; 285 } 286 } 287 } 288 289 /* Second pass: all other objects. */ 290 SIMPLEQ_FOREACH(elm, &initlist, link) { 291 _rtld_call_init_function(elm->obj, mask, cur_objgen); 292 if (_rtld_objgen != cur_objgen) { 293 dbg(("restarting init iteration")); 294 _rtld_objlist_clear(&initlist); 295 goto restart; 296 } 297 } 298 299 _rtld_objlist_clear(&initlist); 300 } 301 302 /* 303 * Initialize the dynamic linker. The argument is the address at which 304 * the dynamic linker has been mapped into memory. The primary task of 305 * this function is to create an Obj_Entry for the dynamic linker and 306 * to resolve the PLT relocation for platforms that need it (those that 307 * define __HAVE_FUNCTION_DESCRIPTORS 308 */ 309 static void 310 _rtld_init(caddr_t mapbase, caddr_t relocbase, const char *execname) 311 { 312 313 /* Conjure up an Obj_Entry structure for the dynamic linker. */ 314 _rtld_objself.path = __UNCONST(_rtld_path); 315 _rtld_objself.pathlen = sizeof(_rtld_path)-1; 316 _rtld_objself.rtld = true; 317 _rtld_objself.mapbase = mapbase; 318 _rtld_objself.relocbase = relocbase; 319 _rtld_objself.dynamic = (Elf_Dyn *) &_DYNAMIC; 320 _rtld_objself.strtab = "_rtld_sym_zero"; 321 322 /* 323 * Set value to -relocbase so that 324 * 325 * _rtld_objself.relocbase + _rtld_sym_zero.st_value == 0 326 * 327 * This allows unresolved references to weak symbols to be computed 328 * to a value of 0. 329 */ 330 _rtld_sym_zero.st_value = -(uintptr_t)relocbase; 331 332 _rtld_digest_dynamic(_rtld_path, &_rtld_objself); 333 assert(!_rtld_objself.needed); 334 #if !defined(__hppa__) 335 assert(!_rtld_objself.pltrel && !_rtld_objself.pltrela); 336 #else 337 _rtld_relocate_plt_objects(&_rtld_objself); 338 #endif 339 #if !defined(__mips__) && !defined(__hppa__) 340 assert(!_rtld_objself.pltgot); 341 #endif 342 #if !defined(__arm__) && !defined(__mips__) && !defined(__sh__) 343 /* ARM, MIPS and SH{3,5} have a bogus DT_TEXTREL. */ 344 assert(!_rtld_objself.textrel); 345 #endif 346 347 _rtld_add_paths(execname, &_rtld_default_paths, 348 RTLD_DEFAULT_LIBRARY_PATH); 349 350 #ifdef RTLD_ARCH_SUBDIR 351 _rtld_add_paths(execname, &_rtld_default_paths, 352 RTLD_DEFAULT_LIBRARY_PATH "/" RTLD_ARCH_SUBDIR); 353 #endif 354 355 /* Make the object list empty. */ 356 _rtld_objlist = NULL; 357 _rtld_objtail = &_rtld_objlist; 358 _rtld_objcount = 0; 359 360 _rtld_debug.r_brk = _rtld_debug_state; 361 _rtld_debug.r_state = RT_CONSISTENT; 362 } 363 364 /* 365 * Cleanup procedure. It will be called (by the atexit() mechanism) just 366 * before the process exits. 367 */ 368 static void 369 _rtld_exit(void) 370 { 371 sigset_t mask; 372 373 dbg(("rtld_exit()")); 374 375 _rtld_exclusive_enter(&mask); 376 377 _rtld_call_fini_functions(&mask, 1); 378 379 _rtld_exclusive_exit(&mask); 380 } 381 382 __dso_public void * 383 _dlauxinfo(void) 384 { 385 return auxinfo; 386 } 387 388 /* 389 * Main entry point for dynamic linking. The argument is the stack 390 * pointer. The stack is expected to be laid out as described in the 391 * SVR4 ABI specification, Intel 386 Processor Supplement. Specifically, 392 * the stack pointer points to a word containing ARGC. Following that 393 * in the stack is a null-terminated sequence of pointers to argument 394 * strings. Then comes a null-terminated sequence of pointers to 395 * environment strings. Finally, there is a sequence of "auxiliary 396 * vector" entries. 397 * 398 * This function returns the entry point for the main program, the dynamic 399 * linker's exit procedure in sp[0], and a pointer to the main object in 400 * sp[1]. 401 */ 402 Elf_Addr 403 _rtld(Elf_Addr *sp, Elf_Addr relocbase) 404 { 405 const AuxInfo *pAUX_base, *pAUX_entry, *pAUX_execfd, *pAUX_phdr, 406 *pAUX_phent, *pAUX_phnum, *pAUX_euid, *pAUX_egid, 407 *pAUX_ruid, *pAUX_rgid; 408 const AuxInfo *pAUX_pagesz; 409 char **env, **oenvp; 410 const AuxInfo *auxp; 411 Obj_Entry *obj; 412 Elf_Addr *const osp = sp; 413 bool bind_now = 0; 414 const char *ld_bind_now, *ld_preload, *ld_library_path; 415 const char **argv; 416 const char *execname; 417 long argc; 418 const char **real___progname; 419 const Obj_Entry **real___mainprog_obj; 420 char ***real_environ; 421 sigset_t mask; 422 #ifdef DEBUG 423 const char *ld_debug; 424 #endif 425 #ifdef RTLD_DEBUG 426 int i = 0; 427 #endif 428 429 /* 430 * On entry, the dynamic linker itself has not been relocated yet. 431 * Be very careful not to reference any global data until after 432 * _rtld_init has returned. It is OK to reference file-scope statics 433 * and string constants, and to call static and global functions. 434 */ 435 /* Find the auxiliary vector on the stack. */ 436 /* first Elf_Word reserved to address of exit routine */ 437 #if defined(RTLD_DEBUG) 438 debug = 1; 439 dbg(("sp = %p, argc = %ld, argv = %p <%s> relocbase %p", sp, 440 (long)sp[2], &sp[3], (char *) sp[3], (void *)relocbase)); 441 #ifndef __x86_64__ 442 dbg(("got is at %p, dynamic is at %p", _GLOBAL_OFFSET_TABLE_, 443 &_DYNAMIC)); 444 #endif 445 #endif 446 447 sp += 2; /* skip over return argument space */ 448 argv = (const char **) &sp[1]; 449 argc = *(long *)sp; 450 sp += 2 + argc; /* Skip over argc, arguments, and NULL 451 * terminator */ 452 env = (char **) sp; 453 while (*sp++ != 0) { /* Skip over environment, and NULL terminator */ 454 #if defined(RTLD_DEBUG) 455 dbg(("env[%d] = %p %s", i++, (void *)sp[-1], (char *)sp[-1])); 456 #endif 457 } 458 auxinfo = (AuxInfo *) sp; 459 460 pAUX_base = pAUX_entry = pAUX_execfd = NULL; 461 pAUX_phdr = pAUX_phent = pAUX_phnum = NULL; 462 pAUX_euid = pAUX_ruid = pAUX_egid = pAUX_rgid = NULL; 463 pAUX_pagesz = NULL; 464 465 execname = NULL; 466 467 /* Digest the auxiliary vector. */ 468 for (auxp = auxinfo; auxp->a_type != AT_NULL; ++auxp) { 469 switch (auxp->a_type) { 470 case AT_BASE: 471 pAUX_base = auxp; 472 break; 473 case AT_ENTRY: 474 pAUX_entry = auxp; 475 break; 476 case AT_EXECFD: 477 pAUX_execfd = auxp; 478 break; 479 case AT_PHDR: 480 pAUX_phdr = auxp; 481 break; 482 case AT_PHENT: 483 pAUX_phent = auxp; 484 break; 485 case AT_PHNUM: 486 pAUX_phnum = auxp; 487 break; 488 #ifdef AT_EUID 489 case AT_EUID: 490 pAUX_euid = auxp; 491 break; 492 case AT_RUID: 493 pAUX_ruid = auxp; 494 break; 495 case AT_EGID: 496 pAUX_egid = auxp; 497 break; 498 case AT_RGID: 499 pAUX_rgid = auxp; 500 break; 501 #endif 502 #ifdef AT_SUN_EXECNAME 503 case AT_SUN_EXECNAME: 504 execname = (const char *)(const void *)auxp->a_v; 505 break; 506 #endif 507 case AT_PAGESZ: 508 pAUX_pagesz = auxp; 509 break; 510 } 511 } 512 513 /* Initialize and relocate ourselves. */ 514 if (pAUX_base == NULL) { 515 _rtld_error("Bad pAUX_base"); 516 _rtld_die(); 517 } 518 assert(pAUX_pagesz != NULL); 519 _rtld_pagesz = (int)pAUX_pagesz->a_v; 520 _rtld_init((caddr_t)pAUX_base->a_v, (caddr_t)relocbase, execname); 521 522 __progname = _rtld_objself.path; 523 environ = env; 524 525 _rtld_trust = ((pAUX_euid ? (uid_t)pAUX_euid->a_v : geteuid()) == 526 (pAUX_ruid ? (uid_t)pAUX_ruid->a_v : getuid())) && 527 ((pAUX_egid ? (gid_t)pAUX_egid->a_v : getegid()) == 528 (pAUX_rgid ? (gid_t)pAUX_rgid->a_v : getgid())); 529 530 #ifdef DEBUG 531 ld_debug = NULL; 532 #endif 533 ld_bind_now = NULL; 534 ld_library_path = NULL; 535 ld_preload = NULL; 536 /* 537 * Inline avoid using normal getenv/unsetenv here as the libc 538 * code is quite a bit more complicated. 539 */ 540 for (oenvp = env; *env != NULL; ++env) { 541 static const char bind_var[] = "LD_BIND_NOW="; 542 static const char debug_var[] = "LD_DEBUG="; 543 static const char path_var[] = "LD_LIBRARY_PATH="; 544 static const char preload_var[] = "LD_PRELOAD="; 545 #define LEN(x) (sizeof(x) - 1) 546 547 if ((*env)[0] != 'L' || (*env)[1] != 'D') { 548 /* 549 * Special case to skip most entries without 550 * the more expensive calls to strncmp. 551 */ 552 *oenvp++ = *env; 553 } else if (strncmp(*env, debug_var, LEN(debug_var)) == 0) { 554 if (_rtld_trust) { 555 #ifdef DEBUG 556 ld_debug = *env + LEN(debug_var); 557 #endif 558 *oenvp++ = *env; 559 } 560 } else if (strncmp(*env, bind_var, LEN(bind_var)) == 0) { 561 ld_bind_now = *env + LEN(bind_var); 562 } else if (strncmp(*env, path_var, LEN(path_var)) == 0) { 563 if (_rtld_trust) { 564 ld_library_path = *env + LEN(path_var); 565 *oenvp++ = *env; 566 } 567 } else if (strncmp(*env, preload_var, LEN(preload_var)) == 0) { 568 if (_rtld_trust) { 569 ld_preload = *env + LEN(preload_var); 570 *oenvp++ = *env; 571 } 572 } else { 573 *oenvp++ = *env; 574 } 575 #undef LEN 576 } 577 *oenvp++ = NULL; 578 579 if (ld_bind_now != NULL && *ld_bind_now != '\0') 580 bind_now = true; 581 if (_rtld_trust) { 582 #ifdef DEBUG 583 #ifdef RTLD_DEBUG 584 debug = 0; 585 #endif 586 if (ld_debug != NULL && *ld_debug != '\0') 587 debug = 1; 588 #endif 589 _rtld_add_paths(execname, &_rtld_paths, ld_library_path); 590 } else { 591 execname = NULL; 592 } 593 _rtld_process_hints(execname, &_rtld_paths, &_rtld_xforms, 594 _PATH_LD_HINTS); 595 dbg(("dynamic linker is initialized, mapbase=%p, relocbase=%p", 596 _rtld_objself.mapbase, _rtld_objself.relocbase)); 597 598 /* 599 * Load the main program, or process its program header if it is 600 * already loaded. 601 */ 602 if (pAUX_execfd != NULL) { /* Load the main program. */ 603 int fd = pAUX_execfd->a_v; 604 const char *obj_name = argv[0] ? argv[0] : "main program"; 605 dbg(("loading main program")); 606 _rtld_objmain = _rtld_map_object(obj_name, fd, NULL); 607 close(fd); 608 if (_rtld_objmain == NULL) 609 _rtld_die(); 610 } else { /* Main program already loaded. */ 611 const Elf_Phdr *phdr; 612 int phnum; 613 caddr_t entry; 614 615 dbg(("processing main program's program header")); 616 assert(pAUX_phdr != NULL); 617 phdr = (const Elf_Phdr *) pAUX_phdr->a_v; 618 assert(pAUX_phnum != NULL); 619 phnum = pAUX_phnum->a_v; 620 assert(pAUX_phent != NULL); 621 assert(pAUX_phent->a_v == sizeof(Elf_Phdr)); 622 assert(pAUX_entry != NULL); 623 entry = (caddr_t) pAUX_entry->a_v; 624 _rtld_objmain = _rtld_digest_phdr(phdr, phnum, entry); 625 _rtld_objmain->path = xstrdup(argv[0] ? argv[0] : 626 "main program"); 627 _rtld_objmain->pathlen = strlen(_rtld_objmain->path); 628 } 629 630 _rtld_objmain->mainprog = true; 631 632 /* 633 * Get the actual dynamic linker pathname from the executable if 634 * possible. (It should always be possible.) That ensures that 635 * gdb will find the right dynamic linker even if a non-standard 636 * one is being used. 637 */ 638 if (_rtld_objmain->interp != NULL && 639 strcmp(_rtld_objmain->interp, _rtld_objself.path) != 0) 640 _rtld_objself.path = xstrdup(_rtld_objmain->interp); 641 dbg(("actual dynamic linker is %s", _rtld_objself.path)); 642 643 _rtld_digest_dynamic(execname, _rtld_objmain); 644 645 /* Link the main program into the list of objects. */ 646 *_rtld_objtail = _rtld_objmain; 647 _rtld_objtail = &_rtld_objmain->next; 648 _rtld_objcount++; 649 _rtld_objloads++; 650 651 _rtld_linkmap_add(_rtld_objmain); 652 _rtld_linkmap_add(&_rtld_objself); 653 654 ++_rtld_objmain->refcount; 655 _rtld_objmain->mainref = 1; 656 _rtld_objlist_push_tail(&_rtld_list_main, _rtld_objmain); 657 658 if (ld_preload) { 659 /* 660 * Pre-load user-specified objects after the main program 661 * but before any shared object dependencies. 662 */ 663 dbg(("preloading objects")); 664 if (_rtld_preload(ld_preload) == -1) 665 _rtld_die(); 666 } 667 668 dbg(("loading needed objects")); 669 if (_rtld_load_needed_objects(_rtld_objmain, _RTLD_MAIN) == -1) 670 _rtld_die(); 671 672 dbg(("checking for required versions")); 673 for (obj = _rtld_objlist; obj != NULL; obj = obj->next) { 674 if (_rtld_verify_object_versions(obj) == -1) 675 _rtld_die(); 676 } 677 678 #if defined(__HAVE_TLS_VARIANT_I) || defined(__HAVE_TLS_VARIANT_II) 679 dbg(("initializing initial Thread Local Storage offsets")); 680 /* 681 * All initial objects get the TLS space from the static block. 682 */ 683 for (obj = _rtld_objlist; obj != NULL; obj = obj->next) 684 _rtld_tls_offset_allocate(obj); 685 #endif 686 687 dbg(("relocating objects")); 688 if (_rtld_relocate_objects(_rtld_objmain, bind_now) == -1) 689 _rtld_die(); 690 691 dbg(("doing copy relocations")); 692 if (_rtld_do_copy_relocations(_rtld_objmain) == -1) 693 _rtld_die(); 694 695 #if defined(__HAVE_TLS_VARIANT_I) || defined(__HAVE_TLS_VARIANT_II) 696 dbg(("initializing Thread Local Storage for main thread")); 697 /* 698 * Set up TLS area for the main thread. 699 * This has to be done after all relocations are processed, 700 * since .tdata may contain relocations. 701 */ 702 _rtld_tls_initial_allocation(); 703 #endif 704 705 /* 706 * Set the __progname, environ and, __mainprog_obj before 707 * calling anything that might use them. 708 */ 709 real___progname = _rtld_objmain_sym("__progname"); 710 if (real___progname) { 711 if (argv[0] != NULL) { 712 if ((*real___progname = strrchr(argv[0], '/')) == NULL) 713 (*real___progname) = argv[0]; 714 else 715 (*real___progname)++; 716 } else { 717 (*real___progname) = NULL; 718 } 719 } 720 real_environ = _rtld_objmain_sym("environ"); 721 if (real_environ) 722 *real_environ = environ; 723 /* 724 * Set __mainprog_obj for old binaries. 725 */ 726 real___mainprog_obj = _rtld_objmain_sym("__mainprog_obj"); 727 if (real___mainprog_obj) 728 *real___mainprog_obj = _rtld_objmain; 729 730 _rtld_exclusive_enter(&mask); 731 732 dbg(("calling _init functions")); 733 _rtld_call_init_functions(&mask); 734 735 dbg(("control at program entry point = %p, obj = %p, exit = %p", 736 _rtld_objmain->entry, _rtld_objmain, _rtld_exit)); 737 738 _rtld_exclusive_exit(&mask); 739 740 /* 741 * Return with the entry point and the exit procedure in at the top 742 * of stack. 743 */ 744 745 _rtld_debug_state(); /* say hello to gdb! */ 746 747 ((void **) osp)[0] = _rtld_exit; 748 ((void **) osp)[1] = _rtld_objmain; 749 return (Elf_Addr) _rtld_objmain->entry; 750 } 751 752 void 753 _rtld_die(void) 754 { 755 const char *msg = dlerror(); 756 757 if (msg == NULL) 758 msg = "Fatal error"; 759 xerrx(1, "%s", msg); 760 } 761 762 static Obj_Entry * 763 _rtld_dlcheck(void *handle) 764 { 765 Obj_Entry *obj; 766 767 for (obj = _rtld_objlist; obj != NULL; obj = obj->next) 768 if (obj == (Obj_Entry *) handle) 769 break; 770 771 if (obj == NULL || obj->dl_refcount == 0) { 772 _rtld_error("Invalid shared object handle %p", handle); 773 return NULL; 774 } 775 return obj; 776 } 777 778 static void 779 _rtld_initlist_visit(Objlist* list, Obj_Entry *obj, int rev) 780 { 781 Needed_Entry* elm; 782 783 /* dbg(("_rtld_initlist_visit(%s)", obj->path)); */ 784 785 if (obj->init_done) 786 return; 787 obj->init_done = 1; 788 789 for (elm = obj->needed; elm != NULL; elm = elm->next) { 790 if (elm->obj != NULL) { 791 _rtld_initlist_visit(list, elm->obj, rev); 792 } 793 } 794 795 if (rev) { 796 _rtld_objlist_push_head(list, obj); 797 } else { 798 _rtld_objlist_push_tail(list, obj); 799 } 800 } 801 802 static void 803 _rtld_initlist_tsort(Objlist* list, int rev) 804 { 805 dbg(("_rtld_initlist_tsort")); 806 807 Obj_Entry* obj; 808 809 for (obj = _rtld_objlist->next; obj; obj = obj->next) { 810 obj->init_done = 0; 811 } 812 813 for (obj = _rtld_objlist->next; obj; obj = obj->next) { 814 _rtld_initlist_visit(list, obj, rev); 815 } 816 } 817 818 static void 819 _rtld_init_dag(Obj_Entry *root) 820 { 821 822 _rtld_init_dag1(root, root); 823 } 824 825 static void 826 _rtld_init_dag1(Obj_Entry *root, Obj_Entry *obj) 827 { 828 const Needed_Entry *needed; 829 830 if (!obj->mainref) { 831 if (_rtld_objlist_find(&obj->dldags, root)) 832 return; 833 dbg(("add %p (%s) to %p (%s) DAG", obj, obj->path, root, 834 root->path)); 835 _rtld_objlist_push_tail(&obj->dldags, root); 836 _rtld_objlist_push_tail(&root->dagmembers, obj); 837 } 838 for (needed = obj->needed; needed != NULL; needed = needed->next) 839 if (needed->obj != NULL) 840 _rtld_init_dag1(root, needed->obj); 841 } 842 843 /* 844 * Note, this is called only for objects loaded by dlopen(). 845 */ 846 static void 847 _rtld_unload_object(sigset_t *mask, Obj_Entry *root, bool do_fini_funcs) 848 { 849 850 _rtld_unref_dag(root); 851 if (root->refcount == 0) { /* We are finished with some objects. */ 852 Obj_Entry *obj; 853 Obj_Entry **linkp; 854 Objlist_Entry *elm; 855 856 /* Finalize objects that are about to be unmapped. */ 857 if (do_fini_funcs) 858 _rtld_call_fini_functions(mask, 0); 859 860 /* Remove the DAG from all objects' DAG lists. */ 861 SIMPLEQ_FOREACH(elm, &root->dagmembers, link) 862 _rtld_objlist_remove(&elm->obj->dldags, root); 863 864 /* Remove the DAG from the RTLD_GLOBAL list. */ 865 if (root->globalref) { 866 root->globalref = 0; 867 _rtld_objlist_remove(&_rtld_list_global, root); 868 } 869 870 /* Unmap all objects that are no longer referenced. */ 871 linkp = &_rtld_objlist->next; 872 while ((obj = *linkp) != NULL) { 873 if (obj->refcount == 0) { 874 dbg(("unloading \"%s\"", obj->path)); 875 if (obj->ehdr != MAP_FAILED) 876 munmap(obj->ehdr, _rtld_pagesz); 877 munmap(obj->mapbase, obj->mapsize); 878 _rtld_objlist_remove(&_rtld_list_global, obj); 879 _rtld_linkmap_delete(obj); 880 *linkp = obj->next; 881 _rtld_objcount--; 882 _rtld_obj_free(obj); 883 } else 884 linkp = &obj->next; 885 } 886 _rtld_objtail = linkp; 887 } 888 } 889 890 void 891 _rtld_ref_dag(Obj_Entry *root) 892 { 893 const Needed_Entry *needed; 894 895 assert(root); 896 897 ++root->refcount; 898 899 dbg(("incremented reference on \"%s\" (%d)", root->path, 900 root->refcount)); 901 for (needed = root->needed; needed != NULL; 902 needed = needed->next) { 903 if (needed->obj != NULL) 904 _rtld_ref_dag(needed->obj); 905 } 906 } 907 908 static void 909 _rtld_unref_dag(Obj_Entry *root) 910 { 911 912 assert(root); 913 assert(root->refcount != 0); 914 915 --root->refcount; 916 dbg(("decremented reference on \"%s\" (%d)", root->path, 917 root->refcount)); 918 919 if (root->refcount == 0) { 920 const Needed_Entry *needed; 921 922 for (needed = root->needed; needed != NULL; 923 needed = needed->next) { 924 if (needed->obj != NULL) 925 _rtld_unref_dag(needed->obj); 926 } 927 } 928 } 929 930 __strong_alias(__dlclose,dlclose) 931 int 932 dlclose(void *handle) 933 { 934 Obj_Entry *root; 935 sigset_t mask; 936 937 dbg(("dlclose of %p", handle)); 938 939 _rtld_exclusive_enter(&mask); 940 941 root = _rtld_dlcheck(handle); 942 943 if (root == NULL) { 944 _rtld_exclusive_exit(&mask); 945 return -1; 946 } 947 948 _rtld_debug.r_state = RT_DELETE; 949 _rtld_debug_state(); 950 951 --root->dl_refcount; 952 _rtld_unload_object(&mask, root, true); 953 954 _rtld_debug.r_state = RT_CONSISTENT; 955 _rtld_debug_state(); 956 957 _rtld_exclusive_exit(&mask); 958 959 return 0; 960 } 961 962 __strong_alias(__dlerror,dlerror) 963 char * 964 dlerror(void) 965 { 966 char *msg = error_message; 967 968 error_message = NULL; 969 return msg; 970 } 971 972 __strong_alias(__dlopen,dlopen) 973 void * 974 dlopen(const char *name, int mode) 975 { 976 Obj_Entry **old_obj_tail = _rtld_objtail; 977 Obj_Entry *obj = NULL; 978 int flags = _RTLD_DLOPEN; 979 bool nodelete; 980 bool now; 981 sigset_t mask; 982 int result; 983 984 dbg(("dlopen of %s %d", name, mode)); 985 986 _rtld_exclusive_enter(&mask); 987 988 flags |= (mode & RTLD_GLOBAL) ? _RTLD_GLOBAL : 0; 989 flags |= (mode & RTLD_NOLOAD) ? _RTLD_NOLOAD : 0; 990 991 nodelete = (mode & RTLD_NODELETE) ? true : false; 992 now = ((mode & RTLD_MODEMASK) == RTLD_NOW) ? true : false; 993 994 _rtld_debug.r_state = RT_ADD; 995 _rtld_debug_state(); 996 997 if (name == NULL) { 998 obj = _rtld_objmain; 999 obj->refcount++; 1000 } else 1001 obj = _rtld_load_library(name, _rtld_objmain, flags); 1002 1003 1004 if (obj != NULL) { 1005 ++obj->dl_refcount; 1006 if (*old_obj_tail != NULL) { /* We loaded something new. */ 1007 assert(*old_obj_tail == obj); 1008 1009 result = _rtld_load_needed_objects(obj, flags); 1010 if (result != -1) { 1011 Objlist_Entry *entry; 1012 _rtld_init_dag(obj); 1013 SIMPLEQ_FOREACH(entry, &obj->dagmembers, link) { 1014 result = _rtld_verify_object_versions(entry->obj); 1015 if (result == -1) 1016 break; 1017 } 1018 } 1019 if (result == -1 || _rtld_relocate_objects(obj, 1020 (now || obj->z_now)) == -1) { 1021 _rtld_unload_object(&mask, obj, false); 1022 obj->dl_refcount--; 1023 obj = NULL; 1024 } else { 1025 _rtld_call_init_functions(&mask); 1026 } 1027 } 1028 if (obj != NULL) { 1029 if ((nodelete || obj->z_nodelete) && !obj->ref_nodel) { 1030 dbg(("dlopen obj %s nodelete", obj->path)); 1031 _rtld_ref_dag(obj); 1032 obj->z_nodelete = obj->ref_nodel = true; 1033 } 1034 } 1035 } 1036 _rtld_debug.r_state = RT_CONSISTENT; 1037 _rtld_debug_state(); 1038 1039 _rtld_exclusive_exit(&mask); 1040 1041 return obj; 1042 } 1043 1044 /* 1045 * Find a symbol in the main program. 1046 */ 1047 void * 1048 _rtld_objmain_sym(const char *name) 1049 { 1050 unsigned long hash; 1051 const Elf_Sym *def; 1052 const Obj_Entry *obj; 1053 DoneList donelist; 1054 1055 hash = _rtld_elf_hash(name); 1056 obj = _rtld_objmain; 1057 _rtld_donelist_init(&donelist); 1058 1059 def = _rtld_symlook_list(name, hash, &_rtld_list_main, &obj, 0, 1060 NULL, &donelist); 1061 1062 if (def != NULL) 1063 return obj->relocbase + def->st_value; 1064 return NULL; 1065 } 1066 1067 #ifdef __powerpc__ 1068 static void * 1069 hackish_return_address(void) 1070 { 1071 return __builtin_return_address(1); 1072 } 1073 #endif 1074 1075 #ifdef __HAVE_FUNCTION_DESCRIPTORS 1076 #define lookup_mutex_enter() _rtld_exclusive_enter(&mask) 1077 #define lookup_mutex_exit() _rtld_exclusive_exit(&mask) 1078 #else 1079 #define lookup_mutex_enter() _rtld_shared_enter() 1080 #define lookup_mutex_exit() _rtld_shared_exit() 1081 #endif 1082 1083 static void * 1084 do_dlsym(void *handle, const char *name, const Ver_Entry *ventry, void *retaddr) 1085 { 1086 const Obj_Entry *obj; 1087 unsigned long hash; 1088 const Elf_Sym *def; 1089 const Obj_Entry *defobj; 1090 DoneList donelist; 1091 const u_int flags = SYMLOOK_DLSYM | SYMLOOK_IN_PLT; 1092 #ifdef __HAVE_FUNCTION_DESCRIPTORS 1093 sigset_t mask; 1094 #endif 1095 1096 lookup_mutex_enter(); 1097 1098 hash = _rtld_elf_hash(name); 1099 def = NULL; 1100 defobj = NULL; 1101 1102 switch ((intptr_t)handle) { 1103 case (intptr_t)NULL: 1104 case (intptr_t)RTLD_NEXT: 1105 case (intptr_t)RTLD_DEFAULT: 1106 case (intptr_t)RTLD_SELF: 1107 if ((obj = _rtld_obj_from_addr(retaddr)) == NULL) { 1108 _rtld_error("Cannot determine caller's shared object"); 1109 lookup_mutex_exit(); 1110 return NULL; 1111 } 1112 1113 switch ((intptr_t)handle) { 1114 case (intptr_t)NULL: /* Just the caller's shared object. */ 1115 def = _rtld_symlook_obj(name, hash, obj, flags, ventry); 1116 defobj = obj; 1117 break; 1118 1119 case (intptr_t)RTLD_NEXT: /* Objects after callers */ 1120 obj = obj->next; 1121 /*FALLTHROUGH*/ 1122 1123 case (intptr_t)RTLD_SELF: /* Caller included */ 1124 for (; obj; obj = obj->next) { 1125 if ((def = _rtld_symlook_obj(name, hash, obj, 1126 flags, ventry)) != NULL) { 1127 defobj = obj; 1128 break; 1129 } 1130 } 1131 break; 1132 1133 case (intptr_t)RTLD_DEFAULT: 1134 def = _rtld_symlook_default(name, hash, obj, &defobj, 1135 flags, ventry); 1136 break; 1137 1138 default: 1139 abort(); 1140 } 1141 break; 1142 1143 default: 1144 if ((obj = _rtld_dlcheck(handle)) == NULL) { 1145 lookup_mutex_exit(); 1146 return NULL; 1147 } 1148 1149 _rtld_donelist_init(&donelist); 1150 1151 if (obj->mainprog) { 1152 /* Search main program and all libraries loaded by it */ 1153 def = _rtld_symlook_list(name, hash, &_rtld_list_main, 1154 &defobj, flags, ventry, &donelist); 1155 } else { 1156 Needed_Entry fake; 1157 DoneList depth; 1158 1159 /* Search the object and all the libraries loaded by it. */ 1160 fake.next = NULL; 1161 fake.obj = __UNCONST(obj); 1162 fake.name = 0; 1163 1164 _rtld_donelist_init(&depth); 1165 def = _rtld_symlook_needed(name, hash, &fake, &defobj, 1166 flags, ventry, &donelist, &depth); 1167 } 1168 1169 break; 1170 } 1171 1172 if (def != NULL) { 1173 void *p; 1174 #ifdef __HAVE_FUNCTION_DESCRIPTORS 1175 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) { 1176 p = (void *)_rtld_function_descriptor_alloc(defobj, 1177 def, 0); 1178 lookup_mutex_exit(); 1179 return p; 1180 } 1181 #endif /* __HAVE_FUNCTION_DESCRIPTORS */ 1182 p = defobj->relocbase + def->st_value; 1183 lookup_mutex_exit(); 1184 return p; 1185 } 1186 1187 _rtld_error("Undefined symbol \"%s\"", name); 1188 lookup_mutex_exit(); 1189 return NULL; 1190 } 1191 1192 __strong_alias(__dlsym,dlsym) 1193 void * 1194 dlsym(void *handle, const char *name) 1195 { 1196 void *retaddr; 1197 1198 dbg(("dlsym of %s in %p", name, handle)); 1199 1200 #ifdef __powerpc__ 1201 retaddr = hackish_return_address(); 1202 #else 1203 retaddr = __builtin_return_address(0); 1204 #endif 1205 return do_dlsym(handle, name, NULL, retaddr); 1206 } 1207 1208 __strong_alias(__dlvsym,dlvsym) 1209 void * 1210 dlvsym(void *handle, const char *name, const char *version) 1211 { 1212 Ver_Entry *ventry = NULL; 1213 Ver_Entry ver_entry; 1214 void *retaddr; 1215 1216 dbg(("dlvsym of %s@%s in %p", name, version ? version : NULL, handle)); 1217 1218 if (version != NULL) { 1219 ver_entry.name = version; 1220 ver_entry.file = NULL; 1221 ver_entry.hash = _rtld_elf_hash(version); 1222 ver_entry.flags = 0; 1223 ventry = &ver_entry; 1224 } 1225 #ifdef __powerpc__ 1226 retaddr = hackish_return_address(); 1227 #else 1228 retaddr = __builtin_return_address(0); 1229 #endif 1230 return do_dlsym(handle, name, ventry, retaddr); 1231 } 1232 1233 __strong_alias(__dladdr,dladdr) 1234 int 1235 dladdr(const void *addr, Dl_info *info) 1236 { 1237 const Obj_Entry *obj; 1238 const Elf_Sym *def, *best_def; 1239 void *symbol_addr; 1240 unsigned long symoffset; 1241 #ifdef __HAVE_FUNCTION_DESCRIPTORS 1242 sigset_t mask; 1243 #endif 1244 1245 dbg(("dladdr of %p", addr)); 1246 1247 lookup_mutex_enter(); 1248 1249 #ifdef __HAVE_FUNCTION_DESCRIPTORS 1250 addr = _rtld_function_descriptor_function(addr); 1251 #endif /* __HAVE_FUNCTION_DESCRIPTORS */ 1252 1253 obj = _rtld_obj_from_addr(addr); 1254 if (obj == NULL) { 1255 _rtld_error("No shared object contains address"); 1256 lookup_mutex_enter(); 1257 return 0; 1258 } 1259 info->dli_fname = obj->path; 1260 info->dli_fbase = obj->mapbase; 1261 info->dli_saddr = (void *)0; 1262 info->dli_sname = NULL; 1263 1264 /* 1265 * Walk the symbol list looking for the symbol whose address is 1266 * closest to the address sent in. 1267 */ 1268 best_def = NULL; 1269 for (symoffset = 0; symoffset < obj->nchains; symoffset++) { 1270 def = obj->symtab + symoffset; 1271 1272 /* 1273 * For skip the symbol if st_shndx is either SHN_UNDEF or 1274 * SHN_COMMON. 1275 */ 1276 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 1277 continue; 1278 1279 /* 1280 * If the symbol is greater than the specified address, or if it 1281 * is further away from addr than the current nearest symbol, 1282 * then reject it. 1283 */ 1284 symbol_addr = obj->relocbase + def->st_value; 1285 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 1286 continue; 1287 1288 /* Update our idea of the nearest symbol. */ 1289 info->dli_sname = obj->strtab + def->st_name; 1290 info->dli_saddr = symbol_addr; 1291 best_def = def; 1292 1293 /* Exact match? */ 1294 if (info->dli_saddr == addr) 1295 break; 1296 } 1297 1298 #ifdef __HAVE_FUNCTION_DESCRIPTORS 1299 if (best_def != NULL && ELF_ST_TYPE(best_def->st_info) == STT_FUNC) 1300 info->dli_saddr = (void *)_rtld_function_descriptor_alloc(obj, 1301 best_def, 0); 1302 #endif /* __HAVE_FUNCTION_DESCRIPTORS */ 1303 1304 lookup_mutex_exit(); 1305 return 1; 1306 } 1307 1308 __strong_alias(__dlinfo,dlinfo) 1309 int 1310 dlinfo(void *handle, int req, void *v) 1311 { 1312 const Obj_Entry *obj; 1313 void *retaddr; 1314 1315 dbg(("dlinfo for %p %d", handle, req)); 1316 1317 _rtld_shared_enter(); 1318 1319 if (handle == RTLD_SELF) { 1320 #ifdef __powerpc__ 1321 retaddr = hackish_return_address(); 1322 #else 1323 retaddr = __builtin_return_address(0); 1324 #endif 1325 if ((obj = _rtld_obj_from_addr(retaddr)) == NULL) { 1326 _rtld_error("Cannot determine caller's shared object"); 1327 _rtld_shared_exit(); 1328 return -1; 1329 } 1330 } else { 1331 if ((obj = _rtld_dlcheck(handle)) == NULL) { 1332 _rtld_shared_exit(); 1333 return -1; 1334 } 1335 } 1336 1337 switch (req) { 1338 case RTLD_DI_LINKMAP: 1339 { 1340 const struct link_map **map = v; 1341 1342 *map = &obj->linkmap; 1343 break; 1344 } 1345 1346 default: 1347 _rtld_error("Invalid request"); 1348 _rtld_shared_exit(); 1349 return -1; 1350 } 1351 1352 _rtld_shared_exit(); 1353 return 0; 1354 } 1355 1356 __strong_alias(__dl_iterate_phdr,dl_iterate_phdr); 1357 int 1358 dl_iterate_phdr(int (*callback)(struct dl_phdr_info *, size_t, void *), void *param) 1359 { 1360 struct dl_phdr_info phdr_info; 1361 const Obj_Entry *obj; 1362 int error = 0; 1363 1364 dbg(("dl_iterate_phdr")); 1365 1366 _rtld_shared_enter(); 1367 1368 for (obj = _rtld_objlist; obj != NULL; obj = obj->next) { 1369 phdr_info.dlpi_addr = (Elf_Addr)obj->relocbase; 1370 /* XXX: wrong but not fixing it yet */ 1371 phdr_info.dlpi_name = SIMPLEQ_FIRST(&obj->names) ? 1372 SIMPLEQ_FIRST(&obj->names)->name : obj->path; 1373 phdr_info.dlpi_phdr = obj->phdr; 1374 phdr_info.dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 1375 #if defined(__HAVE_TLS_VARIANT_I) || defined(__HAVE_TLS_VARIANT_II) 1376 phdr_info.dlpi_tls_modid = obj->tlsindex; 1377 phdr_info.dlpi_tls_data = obj->tlsinit; 1378 #else 1379 phdr_info.dlpi_tls_modid = 0; 1380 phdr_info.dlpi_tls_data = 0; 1381 #endif 1382 phdr_info.dlpi_adds = _rtld_objloads; 1383 phdr_info.dlpi_subs = _rtld_objloads - _rtld_objcount; 1384 1385 /* XXXlocking: exit point */ 1386 error = callback(&phdr_info, sizeof(phdr_info), param); 1387 if (error) 1388 break; 1389 } 1390 1391 _rtld_shared_exit(); 1392 return error; 1393 } 1394 1395 /* 1396 * Error reporting function. Use it like printf. If formats the message 1397 * into a buffer, and sets things up so that the next call to dlerror() 1398 * will return the message. 1399 */ 1400 void 1401 _rtld_error(const char *fmt,...) 1402 { 1403 static char buf[512]; 1404 va_list ap; 1405 1406 va_start(ap, fmt); 1407 xvsnprintf(buf, sizeof buf, fmt, ap); 1408 error_message = buf; 1409 va_end(ap); 1410 } 1411 1412 void 1413 _rtld_debug_state(void) 1414 { 1415 1416 /* Prevent optimizer from removing calls to this function */ 1417 __insn_barrier(); 1418 } 1419 1420 void 1421 _rtld_linkmap_add(Obj_Entry *obj) 1422 { 1423 struct link_map *l = &obj->linkmap; 1424 struct link_map *prev; 1425 1426 obj->linkmap.l_name = obj->path; 1427 obj->linkmap.l_addr = obj->relocbase; 1428 obj->linkmap.l_ld = obj->dynamic; 1429 #ifdef __mips__ 1430 /* XXX This field is not standard and will be removed eventually. */ 1431 obj->linkmap.l_offs = obj->relocbase; 1432 #endif 1433 1434 if (_rtld_debug.r_map == NULL) { 1435 _rtld_debug.r_map = l; 1436 return; 1437 } 1438 1439 /* 1440 * Scan to the end of the list, but not past the entry for the 1441 * dynamic linker, which we want to keep at the very end. 1442 */ 1443 for (prev = _rtld_debug.r_map; 1444 prev->l_next != NULL && prev->l_next != &_rtld_objself.linkmap; 1445 prev = prev->l_next); 1446 1447 l->l_prev = prev; 1448 l->l_next = prev->l_next; 1449 if (l->l_next != NULL) 1450 l->l_next->l_prev = l; 1451 prev->l_next = l; 1452 } 1453 1454 void 1455 _rtld_linkmap_delete(Obj_Entry *obj) 1456 { 1457 struct link_map *l = &obj->linkmap; 1458 1459 if (l->l_prev == NULL) { 1460 if ((_rtld_debug.r_map = l->l_next) != NULL) 1461 l->l_next->l_prev = NULL; 1462 return; 1463 } 1464 if ((l->l_prev->l_next = l->l_next) != NULL) 1465 l->l_next->l_prev = l->l_prev; 1466 } 1467 1468 static Obj_Entry * 1469 _rtld_obj_from_addr(const void *addr) 1470 { 1471 Obj_Entry *obj; 1472 1473 for (obj = _rtld_objlist; obj != NULL; obj = obj->next) { 1474 if (addr < (void *) obj->mapbase) 1475 continue; 1476 if (addr < (void *) (obj->mapbase + obj->mapsize)) 1477 return obj; 1478 } 1479 return NULL; 1480 } 1481 1482 static void 1483 _rtld_objlist_clear(Objlist *list) 1484 { 1485 while (!SIMPLEQ_EMPTY(list)) { 1486 Objlist_Entry* elm = SIMPLEQ_FIRST(list); 1487 SIMPLEQ_REMOVE_HEAD(list, link); 1488 xfree(elm); 1489 } 1490 } 1491 1492 static void 1493 _rtld_objlist_remove(Objlist *list, Obj_Entry *obj) 1494 { 1495 Objlist_Entry *elm; 1496 1497 if ((elm = _rtld_objlist_find(list, obj)) != NULL) { 1498 SIMPLEQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 1499 xfree(elm); 1500 } 1501 } 1502 1503 #define RTLD_EXCLUSIVE_MASK 0x80000000U 1504 static volatile unsigned int _rtld_mutex; 1505 static volatile unsigned int _rtld_waiter_exclusive; 1506 static volatile unsigned int _rtld_waiter_shared; 1507 1508 void 1509 _rtld_shared_enter(void) 1510 { 1511 unsigned int cur; 1512 lwpid_t waiter, self = 0; 1513 1514 membar_enter(); 1515 1516 for (;;) { 1517 cur = _rtld_mutex; 1518 /* 1519 * First check if we are currently not exclusively locked. 1520 */ 1521 if ((cur & RTLD_EXCLUSIVE_MASK) == 0) { 1522 /* Yes, so increment use counter */ 1523 if (atomic_cas_uint(&_rtld_mutex, cur, cur + 1) != cur) 1524 continue; 1525 return; 1526 } 1527 /* 1528 * Someone has an exclusive lock. Puts us on the waiter list. 1529 */ 1530 if (!self) 1531 self = _lwp_self(); 1532 if (cur == (self | RTLD_EXCLUSIVE_MASK)) { 1533 if (_rtld_mutex_may_recurse) 1534 return; 1535 _rtld_error("dead lock detected"); 1536 _rtld_die(); 1537 } 1538 waiter = atomic_swap_uint(&_rtld_waiter_shared, self); 1539 /* 1540 * Check for race against _rtld_exclusive_exit before sleeping. 1541 */ 1542 if ((_rtld_mutex & RTLD_EXCLUSIVE_MASK) || 1543 _rtld_waiter_exclusive) 1544 _lwp_park(NULL, 0, __UNVOLATILE(&_rtld_mutex), NULL); 1545 /* Try to remove us from the waiter list. */ 1546 atomic_cas_uint(&_rtld_waiter_shared, self, 0); 1547 if (waiter) 1548 _lwp_unpark(waiter, __UNVOLATILE(&_rtld_mutex)); 1549 } 1550 } 1551 1552 void 1553 _rtld_shared_exit(void) 1554 { 1555 lwpid_t waiter; 1556 1557 /* 1558 * Shared lock taken after an exclusive lock. 1559 * Just assume this is a partial recursion. 1560 */ 1561 if (_rtld_mutex & RTLD_EXCLUSIVE_MASK) 1562 return; 1563 1564 /* 1565 * Wakeup LWPs waiting for an exclusive lock if this is the last 1566 * LWP on the shared lock. 1567 */ 1568 if (atomic_dec_uint_nv(&_rtld_mutex)) 1569 return; 1570 if ((waiter = _rtld_waiter_exclusive) != 0) 1571 _lwp_unpark(waiter, __UNVOLATILE(&_rtld_mutex)); 1572 1573 membar_exit(); 1574 } 1575 1576 void 1577 _rtld_exclusive_enter(sigset_t *mask) 1578 { 1579 lwpid_t waiter, self = _lwp_self(); 1580 unsigned int locked_value = (unsigned int)self | RTLD_EXCLUSIVE_MASK; 1581 unsigned int cur; 1582 sigset_t blockmask; 1583 1584 sigfillset(&blockmask); 1585 sigdelset(&blockmask, SIGTRAP); /* Allow the debugger */ 1586 sigprocmask(SIG_BLOCK, &blockmask, mask); 1587 1588 membar_enter(); 1589 1590 for (;;) { 1591 if (atomic_cas_uint(&_rtld_mutex, 0, locked_value) == 0) 1592 break; 1593 waiter = atomic_swap_uint(&_rtld_waiter_exclusive, self); 1594 cur = _rtld_mutex; 1595 if (cur == locked_value) { 1596 _rtld_error("dead lock detected"); 1597 _rtld_die(); 1598 } 1599 if (cur) 1600 _lwp_park(NULL, 0, __UNVOLATILE(&_rtld_mutex), NULL); 1601 atomic_cas_uint(&_rtld_waiter_exclusive, self, 0); 1602 if (waiter) 1603 _lwp_unpark(waiter, __UNVOLATILE(&_rtld_mutex)); 1604 } 1605 } 1606 1607 void 1608 _rtld_exclusive_exit(sigset_t *mask) 1609 { 1610 lwpid_t waiter; 1611 1612 _rtld_mutex = 0; 1613 if ((waiter = _rtld_waiter_exclusive) != 0) 1614 _lwp_unpark(waiter, __UNVOLATILE(&_rtld_mutex)); 1615 1616 if ((waiter = _rtld_waiter_shared) != 0) 1617 _lwp_unpark(waiter, __UNVOLATILE(&_rtld_mutex)); 1618 1619 membar_exit(); 1620 sigprocmask(SIG_SETMASK, mask, NULL); 1621 } 1622