1 /* $NetBSD: rtld.c,v 1.182 2016/12/01 18:21:39 christos 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 1.182 2016/12/01 18:21:39 christos 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(const Obj_Entry *obj, Elf_Addr func, sigset_t *mask) 140 { 141 _rtld_exclusive_exit(mask); 142 _rtld_call_function_void(obj, 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 == 0 || obj->fini_called)) 150 return; 151 152 if (obj->fini != 0 && !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, 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 Elf_Addr 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(obj, 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 == 0)) 234 return; 235 236 if (!obj->init_called && obj->init != 0) { 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, 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 Elf_Addr 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(obj, 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 if (_rtld_trust) { 562 ld_bind_now = *env + LEN(bind_var); 563 *oenvp++ = *env; 564 } 565 } else if (strncmp(*env, path_var, LEN(path_var)) == 0) { 566 if (_rtld_trust) { 567 ld_library_path = *env + LEN(path_var); 568 *oenvp++ = *env; 569 } 570 } else if (strncmp(*env, preload_var, LEN(preload_var)) == 0) { 571 if (_rtld_trust) { 572 ld_preload = *env + LEN(preload_var); 573 *oenvp++ = *env; 574 } 575 } else { 576 *oenvp++ = *env; 577 } 578 #undef LEN 579 } 580 *oenvp++ = NULL; 581 582 if (ld_bind_now != NULL && *ld_bind_now != '\0') 583 bind_now = true; 584 if (_rtld_trust) { 585 #ifdef DEBUG 586 #ifdef RTLD_DEBUG 587 debug = 0; 588 #endif 589 if (ld_debug != NULL && *ld_debug != '\0') 590 debug = 1; 591 #endif 592 _rtld_add_paths(execname, &_rtld_paths, ld_library_path); 593 } else { 594 execname = NULL; 595 } 596 _rtld_process_hints(execname, &_rtld_paths, &_rtld_xforms, 597 _PATH_LD_HINTS); 598 dbg(("dynamic linker is initialized, mapbase=%p, relocbase=%p", 599 _rtld_objself.mapbase, _rtld_objself.relocbase)); 600 601 /* 602 * Load the main program, or process its program header if it is 603 * already loaded. 604 */ 605 if (pAUX_execfd != NULL) { /* Load the main program. */ 606 int fd = pAUX_execfd->a_v; 607 const char *obj_name = argv[0] ? argv[0] : "main program"; 608 dbg(("loading main program")); 609 _rtld_objmain = _rtld_map_object(obj_name, fd, NULL); 610 close(fd); 611 if (_rtld_objmain == NULL) 612 _rtld_die(); 613 } else { /* Main program already loaded. */ 614 const Elf_Phdr *phdr; 615 int phnum; 616 caddr_t entry; 617 618 dbg(("processing main program's program header")); 619 assert(pAUX_phdr != NULL); 620 phdr = (const Elf_Phdr *) pAUX_phdr->a_v; 621 assert(pAUX_phnum != NULL); 622 phnum = pAUX_phnum->a_v; 623 assert(pAUX_phent != NULL); 624 assert(pAUX_phent->a_v == sizeof(Elf_Phdr)); 625 assert(pAUX_entry != NULL); 626 entry = (caddr_t) pAUX_entry->a_v; 627 _rtld_objmain = _rtld_digest_phdr(phdr, phnum, entry); 628 _rtld_objmain->path = xstrdup(argv[0] ? argv[0] : 629 "main program"); 630 _rtld_objmain->pathlen = strlen(_rtld_objmain->path); 631 } 632 633 _rtld_objmain->mainprog = true; 634 635 /* 636 * Get the actual dynamic linker pathname from the executable if 637 * possible. (It should always be possible.) That ensures that 638 * gdb will find the right dynamic linker even if a non-standard 639 * one is being used. 640 */ 641 if (_rtld_objmain->interp != NULL && 642 strcmp(_rtld_objmain->interp, _rtld_objself.path) != 0) { 643 _rtld_objself.path = xstrdup(_rtld_objmain->interp); 644 _rtld_objself.pathlen = strlen(_rtld_objself.path); 645 } 646 dbg(("actual dynamic linker is %s", _rtld_objself.path)); 647 648 _rtld_digest_dynamic(execname, _rtld_objmain); 649 650 /* Link the main program into the list of objects. */ 651 *_rtld_objtail = _rtld_objmain; 652 _rtld_objtail = &_rtld_objmain->next; 653 _rtld_objcount++; 654 _rtld_objloads++; 655 656 _rtld_linkmap_add(_rtld_objmain); 657 _rtld_objself.path = xstrdup(_rtld_objself.path); 658 _rtld_linkmap_add(&_rtld_objself); 659 660 ++_rtld_objmain->refcount; 661 _rtld_objmain->mainref = 1; 662 _rtld_objlist_push_tail(&_rtld_list_main, _rtld_objmain); 663 664 if (ld_preload) { 665 /* 666 * Pre-load user-specified objects after the main program 667 * but before any shared object dependencies. 668 */ 669 dbg(("preloading objects")); 670 if (_rtld_preload(ld_preload) == -1) 671 _rtld_die(); 672 } 673 674 dbg(("loading needed objects")); 675 if (_rtld_load_needed_objects(_rtld_objmain, _RTLD_MAIN) == -1) 676 _rtld_die(); 677 678 dbg(("checking for required versions")); 679 for (obj = _rtld_objlist; obj != NULL; obj = obj->next) { 680 if (_rtld_verify_object_versions(obj) == -1) 681 _rtld_die(); 682 } 683 684 #if defined(__HAVE_TLS_VARIANT_I) || defined(__HAVE_TLS_VARIANT_II) 685 dbg(("initializing initial Thread Local Storage offsets")); 686 /* 687 * All initial objects get the TLS space from the static block. 688 */ 689 for (obj = _rtld_objlist; obj != NULL; obj = obj->next) 690 _rtld_tls_offset_allocate(obj); 691 #endif 692 693 dbg(("relocating objects")); 694 if (_rtld_relocate_objects(_rtld_objmain, bind_now) == -1) 695 _rtld_die(); 696 697 dbg(("doing copy relocations")); 698 if (_rtld_do_copy_relocations(_rtld_objmain) == -1) 699 _rtld_die(); 700 701 #if defined(__HAVE_TLS_VARIANT_I) || defined(__HAVE_TLS_VARIANT_II) 702 dbg(("initializing Thread Local Storage for main thread")); 703 /* 704 * Set up TLS area for the main thread. 705 * This has to be done after all relocations are processed, 706 * since .tdata may contain relocations. 707 */ 708 _rtld_tls_initial_allocation(); 709 #endif 710 711 /* 712 * Set the __progname, environ and, __mainprog_obj before 713 * calling anything that might use them. 714 */ 715 real___progname = _rtld_objmain_sym("__progname"); 716 if (real___progname) { 717 if (argv[0] != NULL) { 718 if ((*real___progname = strrchr(argv[0], '/')) == NULL) 719 (*real___progname) = argv[0]; 720 else 721 (*real___progname)++; 722 } else { 723 (*real___progname) = NULL; 724 } 725 } 726 real_environ = _rtld_objmain_sym("environ"); 727 if (real_environ) 728 *real_environ = environ; 729 /* 730 * Set __mainprog_obj for old binaries. 731 */ 732 real___mainprog_obj = _rtld_objmain_sym("__mainprog_obj"); 733 if (real___mainprog_obj) 734 *real___mainprog_obj = _rtld_objmain; 735 736 _rtld_exclusive_enter(&mask); 737 738 dbg(("calling _init functions")); 739 _rtld_call_init_functions(&mask); 740 741 dbg(("control at program entry point = %p, obj = %p, exit = %p", 742 _rtld_objmain->entry, _rtld_objmain, _rtld_exit)); 743 744 _rtld_exclusive_exit(&mask); 745 746 /* 747 * Return with the entry point and the exit procedure in at the top 748 * of stack. 749 */ 750 751 _rtld_debug_state(); /* say hello to gdb! */ 752 753 ((void **) osp)[0] = _rtld_exit; 754 ((void **) osp)[1] = _rtld_objmain; 755 return (Elf_Addr) _rtld_objmain->entry; 756 } 757 758 void 759 _rtld_die(void) 760 { 761 const char *msg = dlerror(); 762 763 if (msg == NULL) 764 msg = "Fatal error"; 765 xerrx(1, "%s", msg); 766 } 767 768 static Obj_Entry * 769 _rtld_dlcheck(void *handle) 770 { 771 Obj_Entry *obj; 772 773 for (obj = _rtld_objlist; obj != NULL; obj = obj->next) 774 if (obj == (Obj_Entry *) handle) 775 break; 776 777 if (obj == NULL || obj->dl_refcount == 0) { 778 _rtld_error("Invalid shared object handle %p", handle); 779 return NULL; 780 } 781 return obj; 782 } 783 784 static void 785 _rtld_initlist_visit(Objlist* list, Obj_Entry *obj, int rev) 786 { 787 Needed_Entry* elm; 788 789 /* dbg(("_rtld_initlist_visit(%s)", obj->path)); */ 790 791 if (obj->init_done) 792 return; 793 obj->init_done = 1; 794 795 for (elm = obj->needed; elm != NULL; elm = elm->next) { 796 if (elm->obj != NULL) { 797 _rtld_initlist_visit(list, elm->obj, rev); 798 } 799 } 800 801 if (rev) { 802 _rtld_objlist_push_head(list, obj); 803 } else { 804 _rtld_objlist_push_tail(list, obj); 805 } 806 } 807 808 static void 809 _rtld_initlist_tsort(Objlist* list, int rev) 810 { 811 dbg(("_rtld_initlist_tsort")); 812 813 Obj_Entry* obj; 814 815 for (obj = _rtld_objlist->next; obj; obj = obj->next) { 816 obj->init_done = 0; 817 } 818 819 for (obj = _rtld_objlist->next; obj; obj = obj->next) { 820 _rtld_initlist_visit(list, obj, rev); 821 } 822 } 823 824 static void 825 _rtld_init_dag(Obj_Entry *root) 826 { 827 828 _rtld_init_dag1(root, root); 829 } 830 831 static void 832 _rtld_init_dag1(Obj_Entry *root, Obj_Entry *obj) 833 { 834 const Needed_Entry *needed; 835 836 if (!obj->mainref) { 837 if (_rtld_objlist_find(&obj->dldags, root)) 838 return; 839 dbg(("add %p (%s) to %p (%s) DAG", obj, obj->path, root, 840 root->path)); 841 _rtld_objlist_push_tail(&obj->dldags, root); 842 _rtld_objlist_push_tail(&root->dagmembers, obj); 843 } 844 for (needed = obj->needed; needed != NULL; needed = needed->next) 845 if (needed->obj != NULL) 846 _rtld_init_dag1(root, needed->obj); 847 } 848 849 /* 850 * Note, this is called only for objects loaded by dlopen(). 851 */ 852 static void 853 _rtld_unload_object(sigset_t *mask, Obj_Entry *root, bool do_fini_funcs) 854 { 855 856 _rtld_unref_dag(root); 857 if (root->refcount == 0) { /* We are finished with some objects. */ 858 Obj_Entry *obj; 859 Obj_Entry **linkp; 860 Objlist_Entry *elm; 861 862 /* Finalize objects that are about to be unmapped. */ 863 if (do_fini_funcs) 864 _rtld_call_fini_functions(mask, 0); 865 866 /* Remove the DAG from all objects' DAG lists. */ 867 SIMPLEQ_FOREACH(elm, &root->dagmembers, link) 868 _rtld_objlist_remove(&elm->obj->dldags, root); 869 870 /* Remove the DAG from the RTLD_GLOBAL list. */ 871 if (root->globalref) { 872 root->globalref = 0; 873 _rtld_objlist_remove(&_rtld_list_global, root); 874 } 875 876 /* Unmap all objects that are no longer referenced. */ 877 linkp = &_rtld_objlist->next; 878 while ((obj = *linkp) != NULL) { 879 if (obj->refcount == 0) { 880 dbg(("unloading \"%s\"", obj->path)); 881 if (obj->ehdr != MAP_FAILED) 882 munmap(obj->ehdr, _rtld_pagesz); 883 munmap(obj->mapbase, obj->mapsize); 884 _rtld_objlist_remove(&_rtld_list_global, obj); 885 _rtld_linkmap_delete(obj); 886 *linkp = obj->next; 887 _rtld_objcount--; 888 _rtld_obj_free(obj); 889 } else 890 linkp = &obj->next; 891 } 892 _rtld_objtail = linkp; 893 } 894 } 895 896 void 897 _rtld_ref_dag(Obj_Entry *root) 898 { 899 const Needed_Entry *needed; 900 901 assert(root); 902 903 ++root->refcount; 904 905 dbg(("incremented reference on \"%s\" (%d)", root->path, 906 root->refcount)); 907 for (needed = root->needed; needed != NULL; 908 needed = needed->next) { 909 if (needed->obj != NULL) 910 _rtld_ref_dag(needed->obj); 911 } 912 } 913 914 static void 915 _rtld_unref_dag(Obj_Entry *root) 916 { 917 918 assert(root); 919 assert(root->refcount != 0); 920 921 --root->refcount; 922 dbg(("decremented reference on \"%s\" (%d)", root->path, 923 root->refcount)); 924 925 if (root->refcount == 0) { 926 const Needed_Entry *needed; 927 928 for (needed = root->needed; needed != NULL; 929 needed = needed->next) { 930 if (needed->obj != NULL) 931 _rtld_unref_dag(needed->obj); 932 } 933 } 934 } 935 936 __strong_alias(__dlclose,dlclose) 937 int 938 dlclose(void *handle) 939 { 940 Obj_Entry *root; 941 sigset_t mask; 942 943 dbg(("dlclose of %p", handle)); 944 945 _rtld_exclusive_enter(&mask); 946 947 root = _rtld_dlcheck(handle); 948 949 if (root == NULL) { 950 _rtld_exclusive_exit(&mask); 951 return -1; 952 } 953 954 _rtld_debug.r_state = RT_DELETE; 955 _rtld_debug_state(); 956 957 --root->dl_refcount; 958 _rtld_unload_object(&mask, root, true); 959 960 _rtld_debug.r_state = RT_CONSISTENT; 961 _rtld_debug_state(); 962 963 _rtld_exclusive_exit(&mask); 964 965 return 0; 966 } 967 968 __strong_alias(__dlerror,dlerror) 969 char * 970 dlerror(void) 971 { 972 char *msg = error_message; 973 974 error_message = NULL; 975 return msg; 976 } 977 978 __strong_alias(__dlopen,dlopen) 979 void * 980 dlopen(const char *name, int mode) 981 { 982 Obj_Entry **old_obj_tail = _rtld_objtail; 983 Obj_Entry *obj = NULL; 984 int flags = _RTLD_DLOPEN; 985 bool nodelete; 986 bool now; 987 sigset_t mask; 988 int result; 989 990 dbg(("dlopen of %s %d", name, mode)); 991 992 _rtld_exclusive_enter(&mask); 993 994 flags |= (mode & RTLD_GLOBAL) ? _RTLD_GLOBAL : 0; 995 flags |= (mode & RTLD_NOLOAD) ? _RTLD_NOLOAD : 0; 996 997 nodelete = (mode & RTLD_NODELETE) ? true : false; 998 now = ((mode & RTLD_MODEMASK) == RTLD_NOW) ? true : false; 999 1000 _rtld_debug.r_state = RT_ADD; 1001 _rtld_debug_state(); 1002 1003 if (name == NULL) { 1004 obj = _rtld_objmain; 1005 obj->refcount++; 1006 } else 1007 obj = _rtld_load_library(name, _rtld_objmain, flags); 1008 1009 1010 if (obj != NULL) { 1011 ++obj->dl_refcount; 1012 if (*old_obj_tail != NULL) { /* We loaded something new. */ 1013 assert(*old_obj_tail == obj); 1014 1015 result = _rtld_load_needed_objects(obj, flags); 1016 if (result != -1) { 1017 Objlist_Entry *entry; 1018 _rtld_init_dag(obj); 1019 SIMPLEQ_FOREACH(entry, &obj->dagmembers, link) { 1020 result = _rtld_verify_object_versions(entry->obj); 1021 if (result == -1) 1022 break; 1023 } 1024 } 1025 if (result == -1 || _rtld_relocate_objects(obj, 1026 (now || obj->z_now)) == -1) { 1027 _rtld_unload_object(&mask, obj, false); 1028 obj->dl_refcount--; 1029 obj = NULL; 1030 } else { 1031 _rtld_call_init_functions(&mask); 1032 } 1033 } 1034 if (obj != NULL) { 1035 if ((nodelete || obj->z_nodelete) && !obj->ref_nodel) { 1036 dbg(("dlopen obj %s nodelete", obj->path)); 1037 _rtld_ref_dag(obj); 1038 obj->z_nodelete = obj->ref_nodel = true; 1039 } 1040 } 1041 } 1042 _rtld_debug.r_state = RT_CONSISTENT; 1043 _rtld_debug_state(); 1044 1045 _rtld_exclusive_exit(&mask); 1046 1047 return obj; 1048 } 1049 1050 /* 1051 * Find a symbol in the main program. 1052 */ 1053 void * 1054 _rtld_objmain_sym(const char *name) 1055 { 1056 unsigned long hash; 1057 const Elf_Sym *def; 1058 const Obj_Entry *obj; 1059 DoneList donelist; 1060 1061 hash = _rtld_elf_hash(name); 1062 obj = _rtld_objmain; 1063 _rtld_donelist_init(&donelist); 1064 1065 def = _rtld_symlook_list(name, hash, &_rtld_list_main, &obj, 0, 1066 NULL, &donelist); 1067 1068 if (def != NULL) 1069 return obj->relocbase + def->st_value; 1070 return NULL; 1071 } 1072 1073 #ifdef __powerpc__ 1074 static void * 1075 hackish_return_address(void) 1076 { 1077 return __builtin_return_address(1); 1078 } 1079 #endif 1080 1081 #ifdef __HAVE_FUNCTION_DESCRIPTORS 1082 #define lookup_mutex_enter() _rtld_exclusive_enter(&mask) 1083 #define lookup_mutex_exit() _rtld_exclusive_exit(&mask) 1084 #else 1085 #define lookup_mutex_enter() _rtld_shared_enter() 1086 #define lookup_mutex_exit() _rtld_shared_exit() 1087 #endif 1088 1089 static void * 1090 do_dlsym(void *handle, const char *name, const Ver_Entry *ventry, void *retaddr) 1091 { 1092 const Obj_Entry *obj; 1093 unsigned long hash; 1094 const Elf_Sym *def; 1095 const Obj_Entry *defobj; 1096 DoneList donelist; 1097 const u_int flags = SYMLOOK_DLSYM | SYMLOOK_IN_PLT; 1098 #ifdef __HAVE_FUNCTION_DESCRIPTORS 1099 sigset_t mask; 1100 #endif 1101 1102 lookup_mutex_enter(); 1103 1104 hash = _rtld_elf_hash(name); 1105 def = NULL; 1106 defobj = NULL; 1107 1108 switch ((intptr_t)handle) { 1109 case (intptr_t)NULL: 1110 case (intptr_t)RTLD_NEXT: 1111 case (intptr_t)RTLD_DEFAULT: 1112 case (intptr_t)RTLD_SELF: 1113 if ((obj = _rtld_obj_from_addr(retaddr)) == NULL) { 1114 _rtld_error("Cannot determine caller's shared object"); 1115 lookup_mutex_exit(); 1116 return NULL; 1117 } 1118 1119 switch ((intptr_t)handle) { 1120 case (intptr_t)NULL: /* Just the caller's shared object. */ 1121 def = _rtld_symlook_obj(name, hash, obj, flags, ventry); 1122 defobj = obj; 1123 break; 1124 1125 case (intptr_t)RTLD_NEXT: /* Objects after callers */ 1126 obj = obj->next; 1127 /*FALLTHROUGH*/ 1128 1129 case (intptr_t)RTLD_SELF: /* Caller included */ 1130 for (; obj; obj = obj->next) { 1131 if ((def = _rtld_symlook_obj(name, hash, obj, 1132 flags, ventry)) != NULL) { 1133 defobj = obj; 1134 break; 1135 } 1136 } 1137 /* 1138 * Search the dynamic linker itself, and possibly 1139 * resolve the symbol from there if it is not defined 1140 * already or weak. This is how the application links 1141 * to dynamic linker services such as dlopen. 1142 */ 1143 if (!def || ELF_ST_BIND(def->st_info) == STB_WEAK) { 1144 const Elf_Sym *symp = _rtld_symlook_obj(name, 1145 hash, &_rtld_objself, flags, ventry); 1146 if (symp != NULL) { 1147 def = symp; 1148 defobj = &_rtld_objself; 1149 } 1150 } 1151 break; 1152 1153 case (intptr_t)RTLD_DEFAULT: 1154 def = _rtld_symlook_default(name, hash, obj, &defobj, 1155 flags, ventry); 1156 break; 1157 1158 default: 1159 abort(); 1160 } 1161 break; 1162 1163 default: 1164 if ((obj = _rtld_dlcheck(handle)) == NULL) { 1165 lookup_mutex_exit(); 1166 return NULL; 1167 } 1168 1169 _rtld_donelist_init(&donelist); 1170 1171 if (obj->mainprog) { 1172 /* Search main program and all libraries loaded by it */ 1173 def = _rtld_symlook_list(name, hash, &_rtld_list_main, 1174 &defobj, flags, ventry, &donelist); 1175 } else { 1176 Needed_Entry fake; 1177 DoneList depth; 1178 1179 /* Search the object and all the libraries loaded by it. */ 1180 fake.next = NULL; 1181 fake.obj = __UNCONST(obj); 1182 fake.name = 0; 1183 1184 _rtld_donelist_init(&depth); 1185 def = _rtld_symlook_needed(name, hash, &fake, &defobj, 1186 flags, ventry, &donelist, &depth); 1187 } 1188 1189 break; 1190 } 1191 1192 if (def != NULL) { 1193 void *p; 1194 1195 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) { 1196 #ifdef __HAVE_FUNCTION_DESCRIPTORS 1197 lookup_mutex_exit(); 1198 _rtld_shared_enter(); 1199 #endif 1200 p = (void *)_rtld_resolve_ifunc(defobj, def); 1201 _rtld_shared_exit(); 1202 return p; 1203 } 1204 1205 #ifdef __HAVE_FUNCTION_DESCRIPTORS 1206 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) { 1207 p = (void *)_rtld_function_descriptor_alloc(defobj, 1208 def, 0); 1209 lookup_mutex_exit(); 1210 return p; 1211 } 1212 #endif /* __HAVE_FUNCTION_DESCRIPTORS */ 1213 p = defobj->relocbase + def->st_value; 1214 lookup_mutex_exit(); 1215 return p; 1216 } 1217 1218 _rtld_error("Undefined symbol \"%s\"", name); 1219 lookup_mutex_exit(); 1220 return NULL; 1221 } 1222 1223 __strong_alias(__dlsym,dlsym) 1224 void * 1225 dlsym(void *handle, const char *name) 1226 { 1227 void *retaddr; 1228 1229 dbg(("dlsym of %s in %p", name, handle)); 1230 1231 #ifdef __powerpc__ 1232 retaddr = hackish_return_address(); 1233 #else 1234 retaddr = __builtin_return_address(0); 1235 #endif 1236 return do_dlsym(handle, name, NULL, retaddr); 1237 } 1238 1239 __strong_alias(__dlvsym,dlvsym) 1240 void * 1241 dlvsym(void *handle, const char *name, const char *version) 1242 { 1243 Ver_Entry *ventry = NULL; 1244 Ver_Entry ver_entry; 1245 void *retaddr; 1246 1247 dbg(("dlvsym of %s@%s in %p", name, version ? version : NULL, handle)); 1248 1249 if (version != NULL) { 1250 ver_entry.name = version; 1251 ver_entry.file = NULL; 1252 ver_entry.hash = _rtld_elf_hash(version); 1253 ver_entry.flags = 0; 1254 ventry = &ver_entry; 1255 } 1256 #ifdef __powerpc__ 1257 retaddr = hackish_return_address(); 1258 #else 1259 retaddr = __builtin_return_address(0); 1260 #endif 1261 return do_dlsym(handle, name, ventry, retaddr); 1262 } 1263 1264 __strong_alias(__dladdr,dladdr) 1265 int 1266 dladdr(const void *addr, Dl_info *info) 1267 { 1268 const Obj_Entry *obj; 1269 const Elf_Sym *def, *best_def; 1270 void *symbol_addr; 1271 unsigned long symoffset; 1272 #ifdef __HAVE_FUNCTION_DESCRIPTORS 1273 sigset_t mask; 1274 #endif 1275 1276 dbg(("dladdr of %p", addr)); 1277 1278 lookup_mutex_enter(); 1279 1280 #ifdef __HAVE_FUNCTION_DESCRIPTORS 1281 addr = _rtld_function_descriptor_function(addr); 1282 #endif /* __HAVE_FUNCTION_DESCRIPTORS */ 1283 1284 obj = _rtld_obj_from_addr(addr); 1285 if (obj == NULL) { 1286 _rtld_error("No shared object contains address"); 1287 lookup_mutex_exit(); 1288 return 0; 1289 } 1290 info->dli_fname = obj->path; 1291 info->dli_fbase = obj->mapbase; 1292 info->dli_saddr = (void *)0; 1293 info->dli_sname = NULL; 1294 1295 /* 1296 * Walk the symbol list looking for the symbol whose address is 1297 * closest to the address sent in. 1298 */ 1299 best_def = NULL; 1300 for (symoffset = 0; symoffset < obj->nchains; symoffset++) { 1301 def = obj->symtab + symoffset; 1302 1303 /* 1304 * For skip the symbol if st_shndx is either SHN_UNDEF or 1305 * SHN_COMMON. 1306 */ 1307 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 1308 continue; 1309 1310 /* 1311 * If the symbol is greater than the specified address, or if it 1312 * is further away from addr than the current nearest symbol, 1313 * then reject it. 1314 */ 1315 symbol_addr = obj->relocbase + def->st_value; 1316 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 1317 continue; 1318 1319 /* Update our idea of the nearest symbol. */ 1320 info->dli_sname = obj->strtab + def->st_name; 1321 info->dli_saddr = symbol_addr; 1322 best_def = def; 1323 1324 1325 /* Exact match? */ 1326 if (info->dli_saddr == addr) 1327 break; 1328 } 1329 1330 #ifdef __HAVE_FUNCTION_DESCRIPTORS 1331 if (best_def != NULL && ELF_ST_TYPE(best_def->st_info) == STT_FUNC) 1332 info->dli_saddr = (void *)_rtld_function_descriptor_alloc(obj, 1333 best_def, 0); 1334 #else 1335 __USE(best_def); 1336 #endif /* __HAVE_FUNCTION_DESCRIPTORS */ 1337 1338 lookup_mutex_exit(); 1339 return 1; 1340 } 1341 1342 __strong_alias(__dlinfo,dlinfo) 1343 int 1344 dlinfo(void *handle, int req, void *v) 1345 { 1346 const Obj_Entry *obj; 1347 void *retaddr; 1348 1349 dbg(("dlinfo for %p %d", handle, req)); 1350 1351 _rtld_shared_enter(); 1352 1353 if (handle == RTLD_SELF) { 1354 #ifdef __powerpc__ 1355 retaddr = hackish_return_address(); 1356 #else 1357 retaddr = __builtin_return_address(0); 1358 #endif 1359 if ((obj = _rtld_obj_from_addr(retaddr)) == NULL) { 1360 _rtld_error("Cannot determine caller's shared object"); 1361 _rtld_shared_exit(); 1362 return -1; 1363 } 1364 } else { 1365 if ((obj = _rtld_dlcheck(handle)) == NULL) { 1366 _rtld_shared_exit(); 1367 return -1; 1368 } 1369 } 1370 1371 switch (req) { 1372 case RTLD_DI_LINKMAP: 1373 { 1374 const struct link_map **map = v; 1375 1376 *map = &obj->linkmap; 1377 break; 1378 } 1379 1380 default: 1381 _rtld_error("Invalid request"); 1382 _rtld_shared_exit(); 1383 return -1; 1384 } 1385 1386 _rtld_shared_exit(); 1387 return 0; 1388 } 1389 1390 __strong_alias(__dl_iterate_phdr,dl_iterate_phdr); 1391 int 1392 dl_iterate_phdr(int (*callback)(struct dl_phdr_info *, size_t, void *), void *param) 1393 { 1394 struct dl_phdr_info phdr_info; 1395 const Obj_Entry *obj; 1396 int error = 0; 1397 1398 dbg(("dl_iterate_phdr")); 1399 1400 _rtld_shared_enter(); 1401 1402 for (obj = _rtld_objlist; obj != NULL; obj = obj->next) { 1403 phdr_info.dlpi_addr = (Elf_Addr)obj->relocbase; 1404 /* XXX: wrong but not fixing it yet */ 1405 phdr_info.dlpi_name = obj->path; 1406 phdr_info.dlpi_phdr = obj->phdr; 1407 phdr_info.dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 1408 #if defined(__HAVE_TLS_VARIANT_I) || defined(__HAVE_TLS_VARIANT_II) 1409 phdr_info.dlpi_tls_modid = obj->tlsindex; 1410 phdr_info.dlpi_tls_data = obj->tlsinit; 1411 #else 1412 phdr_info.dlpi_tls_modid = 0; 1413 phdr_info.dlpi_tls_data = 0; 1414 #endif 1415 phdr_info.dlpi_adds = _rtld_objloads; 1416 phdr_info.dlpi_subs = _rtld_objloads - _rtld_objcount; 1417 1418 /* XXXlocking: exit point */ 1419 error = callback(&phdr_info, sizeof(phdr_info), param); 1420 if (error) 1421 break; 1422 } 1423 1424 _rtld_shared_exit(); 1425 return error; 1426 } 1427 1428 /* 1429 * Error reporting function. Use it like printf. If formats the message 1430 * into a buffer, and sets things up so that the next call to dlerror() 1431 * will return the message. 1432 */ 1433 void 1434 _rtld_error(const char *fmt,...) 1435 { 1436 static char buf[512]; 1437 va_list ap; 1438 1439 va_start(ap, fmt); 1440 xvsnprintf(buf, sizeof buf, fmt, ap); 1441 error_message = buf; 1442 va_end(ap); 1443 } 1444 1445 void 1446 _rtld_debug_state(void) 1447 { 1448 #if defined(__hppa__) 1449 __asm volatile("nop" ::: "memory"); 1450 #endif 1451 1452 /* Prevent optimizer from removing calls to this function */ 1453 __insn_barrier(); 1454 } 1455 1456 void 1457 _rtld_linkmap_add(Obj_Entry *obj) 1458 { 1459 struct link_map *l = &obj->linkmap; 1460 struct link_map *prev; 1461 1462 obj->linkmap.l_name = obj->path; 1463 obj->linkmap.l_addr = obj->relocbase; 1464 obj->linkmap.l_ld = obj->dynamic; 1465 #ifdef __mips__ 1466 /* XXX This field is not standard and will be removed eventually. */ 1467 obj->linkmap.l_offs = obj->relocbase; 1468 #endif 1469 1470 if (_rtld_debug.r_map == NULL) { 1471 _rtld_debug.r_map = l; 1472 return; 1473 } 1474 1475 /* 1476 * Scan to the end of the list, but not past the entry for the 1477 * dynamic linker, which we want to keep at the very end. 1478 */ 1479 for (prev = _rtld_debug.r_map; 1480 prev->l_next != NULL && prev->l_next != &_rtld_objself.linkmap; 1481 prev = prev->l_next); 1482 1483 l->l_prev = prev; 1484 l->l_next = prev->l_next; 1485 if (l->l_next != NULL) 1486 l->l_next->l_prev = l; 1487 prev->l_next = l; 1488 } 1489 1490 void 1491 _rtld_linkmap_delete(Obj_Entry *obj) 1492 { 1493 struct link_map *l = &obj->linkmap; 1494 1495 if (l->l_prev == NULL) { 1496 if ((_rtld_debug.r_map = l->l_next) != NULL) 1497 l->l_next->l_prev = NULL; 1498 return; 1499 } 1500 if ((l->l_prev->l_next = l->l_next) != NULL) 1501 l->l_next->l_prev = l->l_prev; 1502 } 1503 1504 static Obj_Entry * 1505 _rtld_obj_from_addr(const void *addr) 1506 { 1507 Obj_Entry *obj; 1508 1509 for (obj = _rtld_objlist; obj != NULL; obj = obj->next) { 1510 if (addr < (void *) obj->mapbase) 1511 continue; 1512 if (addr < (void *) (obj->mapbase + obj->mapsize)) 1513 return obj; 1514 } 1515 return NULL; 1516 } 1517 1518 static void 1519 _rtld_objlist_clear(Objlist *list) 1520 { 1521 while (!SIMPLEQ_EMPTY(list)) { 1522 Objlist_Entry* elm = SIMPLEQ_FIRST(list); 1523 SIMPLEQ_REMOVE_HEAD(list, link); 1524 xfree(elm); 1525 } 1526 } 1527 1528 static void 1529 _rtld_objlist_remove(Objlist *list, Obj_Entry *obj) 1530 { 1531 Objlist_Entry *elm; 1532 1533 if ((elm = _rtld_objlist_find(list, obj)) != NULL) { 1534 SIMPLEQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 1535 xfree(elm); 1536 } 1537 } 1538 1539 #define RTLD_EXCLUSIVE_MASK 0x80000000U 1540 static volatile unsigned int _rtld_mutex; 1541 static volatile unsigned int _rtld_waiter_exclusive; 1542 static volatile unsigned int _rtld_waiter_shared; 1543 1544 void 1545 _rtld_shared_enter(void) 1546 { 1547 unsigned int cur; 1548 lwpid_t waiter, self = 0; 1549 1550 membar_enter(); 1551 1552 for (;;) { 1553 cur = _rtld_mutex; 1554 /* 1555 * First check if we are currently not exclusively locked. 1556 */ 1557 if ((cur & RTLD_EXCLUSIVE_MASK) == 0) { 1558 /* Yes, so increment use counter */ 1559 if (atomic_cas_uint(&_rtld_mutex, cur, cur + 1) != cur) 1560 continue; 1561 membar_enter(); 1562 return; 1563 } 1564 /* 1565 * Someone has an exclusive lock. Puts us on the waiter list. 1566 */ 1567 if (!self) 1568 self = _lwp_self(); 1569 if (cur == (self | RTLD_EXCLUSIVE_MASK)) { 1570 if (_rtld_mutex_may_recurse) 1571 return; 1572 _rtld_error("dead lock detected"); 1573 _rtld_die(); 1574 } 1575 waiter = atomic_swap_uint(&_rtld_waiter_shared, self); 1576 /* 1577 * Check for race against _rtld_exclusive_exit before sleeping. 1578 */ 1579 membar_sync(); 1580 if ((_rtld_mutex & RTLD_EXCLUSIVE_MASK) || 1581 _rtld_waiter_exclusive) 1582 _lwp_park(CLOCK_REALTIME, 0, NULL, 0, 1583 __UNVOLATILE(&_rtld_mutex), NULL); 1584 /* Try to remove us from the waiter list. */ 1585 atomic_cas_uint(&_rtld_waiter_shared, self, 0); 1586 if (waiter) 1587 _lwp_unpark(waiter, __UNVOLATILE(&_rtld_mutex)); 1588 } 1589 } 1590 1591 void 1592 _rtld_shared_exit(void) 1593 { 1594 lwpid_t waiter; 1595 1596 /* 1597 * Shared lock taken after an exclusive lock. 1598 * Just assume this is a partial recursion. 1599 */ 1600 if (_rtld_mutex & RTLD_EXCLUSIVE_MASK) 1601 return; 1602 1603 /* 1604 * Wakeup LWPs waiting for an exclusive lock if this is the last 1605 * LWP on the shared lock. 1606 */ 1607 membar_exit(); 1608 if (atomic_dec_uint_nv(&_rtld_mutex)) 1609 return; 1610 membar_sync(); 1611 if ((waiter = _rtld_waiter_exclusive) != 0) 1612 _lwp_unpark(waiter, __UNVOLATILE(&_rtld_mutex)); 1613 } 1614 1615 void 1616 _rtld_exclusive_enter(sigset_t *mask) 1617 { 1618 lwpid_t waiter, self = _lwp_self(); 1619 unsigned int locked_value = (unsigned int)self | RTLD_EXCLUSIVE_MASK; 1620 unsigned int cur; 1621 sigset_t blockmask; 1622 1623 sigfillset(&blockmask); 1624 sigdelset(&blockmask, SIGTRAP); /* Allow the debugger */ 1625 sigprocmask(SIG_BLOCK, &blockmask, mask); 1626 1627 for (;;) { 1628 if (atomic_cas_uint(&_rtld_mutex, 0, locked_value) == 0) { 1629 membar_enter(); 1630 break; 1631 } 1632 waiter = atomic_swap_uint(&_rtld_waiter_exclusive, self); 1633 membar_sync(); 1634 cur = _rtld_mutex; 1635 if (cur == locked_value) { 1636 _rtld_error("dead lock detected"); 1637 _rtld_die(); 1638 } 1639 if (cur) 1640 _lwp_park(CLOCK_REALTIME, 0, NULL, 0, 1641 __UNVOLATILE(&_rtld_mutex), NULL); 1642 atomic_cas_uint(&_rtld_waiter_exclusive, self, 0); 1643 if (waiter) 1644 _lwp_unpark(waiter, __UNVOLATILE(&_rtld_mutex)); 1645 } 1646 } 1647 1648 void 1649 _rtld_exclusive_exit(sigset_t *mask) 1650 { 1651 lwpid_t waiter; 1652 1653 membar_exit(); 1654 _rtld_mutex = 0; 1655 membar_sync(); 1656 if ((waiter = _rtld_waiter_exclusive) != 0) 1657 _lwp_unpark(waiter, __UNVOLATILE(&_rtld_mutex)); 1658 1659 if ((waiter = _rtld_waiter_shared) != 0) 1660 _lwp_unpark(waiter, __UNVOLATILE(&_rtld_mutex)); 1661 1662 sigprocmask(SIG_SETMASK, mask, NULL); 1663 } 1664