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