rtld.c revision 281453
1/*- 2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra. 3 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>. 4 * Copyright 2009-2012 Konstantin Belousov <kib@FreeBSD.ORG>. 5 * Copyright 2012 John Marino <draco@marino.st>. 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 * 28 * $FreeBSD: stable/10/libexec/rtld-elf/rtld.c 281453 2015-04-12 06:45:40Z kib $ 29 */ 30 31/* 32 * Dynamic linker for ELF. 33 * 34 * John Polstra <jdp@polstra.com>. 35 */ 36 37#ifndef __GNUC__ 38#error "GCC is needed to compile this file" 39#endif 40 41#include <sys/param.h> 42#include <sys/mount.h> 43#include <sys/mman.h> 44#include <sys/stat.h> 45#include <sys/sysctl.h> 46#include <sys/uio.h> 47#include <sys/utsname.h> 48#include <sys/ktrace.h> 49 50#include <dlfcn.h> 51#include <err.h> 52#include <errno.h> 53#include <fcntl.h> 54#include <stdarg.h> 55#include <stdio.h> 56#include <stdlib.h> 57#include <string.h> 58#include <unistd.h> 59 60#include "debug.h" 61#include "rtld.h" 62#include "libmap.h" 63#include "rtld_tls.h" 64#include "rtld_printf.h" 65#include "notes.h" 66 67#ifndef COMPAT_32BIT 68#define PATH_RTLD "/libexec/ld-elf.so.1" 69#else 70#define PATH_RTLD "/libexec/ld-elf32.so.1" 71#endif 72 73/* Types. */ 74typedef void (*func_ptr_type)(); 75typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 76 77/* 78 * Function declarations. 79 */ 80static const char *basename(const char *); 81static void die(void) __dead2; 82static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 83 const Elf_Dyn **, const Elf_Dyn **); 84static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *, 85 const Elf_Dyn *); 86static void digest_dynamic(Obj_Entry *, int); 87static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 88static Obj_Entry *dlcheck(void *); 89static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, 90 int lo_flags, int mode, RtldLockState *lockstate); 91static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 92static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 93static bool donelist_check(DoneList *, const Obj_Entry *); 94static void errmsg_restore(char *); 95static char *errmsg_save(void); 96static void *fill_search_info(const char *, size_t, void *); 97static char *find_library(const char *, const Obj_Entry *); 98static const char *gethints(bool); 99static void init_dag(Obj_Entry *); 100static void init_pagesizes(Elf_Auxinfo **aux_info); 101static void init_rtld(caddr_t, Elf_Auxinfo **); 102static void initlist_add_neededs(Needed_Entry *, Objlist *); 103static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *); 104static void linkmap_add(Obj_Entry *); 105static void linkmap_delete(Obj_Entry *); 106static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 107static void unload_filtees(Obj_Entry *); 108static int load_needed_objects(Obj_Entry *, int); 109static int load_preload_objects(void); 110static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 111static void map_stacks_exec(RtldLockState *); 112static Obj_Entry *obj_from_addr(const void *); 113static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 114static void objlist_call_init(Objlist *, RtldLockState *); 115static void objlist_clear(Objlist *); 116static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 117static void objlist_init(Objlist *); 118static void objlist_push_head(Objlist *, Obj_Entry *); 119static void objlist_push_tail(Objlist *, Obj_Entry *); 120static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 121static void objlist_remove(Objlist *, Obj_Entry *); 122static void *path_enumerate(const char *, path_enum_proc, void *); 123static int relocate_object_dag(Obj_Entry *root, bool bind_now, 124 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 125static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 126 int flags, RtldLockState *lockstate); 127static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 128 RtldLockState *); 129static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now, 130 int flags, RtldLockState *lockstate); 131static int rtld_dirname(const char *, char *); 132static int rtld_dirname_abs(const char *, char *); 133static void *rtld_dlopen(const char *name, int fd, int mode); 134static void rtld_exit(void); 135static char *search_library_path(const char *, const char *); 136static const void **get_program_var_addr(const char *, RtldLockState *); 137static void set_program_var(const char *, const void *); 138static int symlook_default(SymLook *, const Obj_Entry *refobj); 139static int symlook_global(SymLook *, DoneList *); 140static void symlook_init_from_req(SymLook *, const SymLook *); 141static int symlook_list(SymLook *, const Objlist *, DoneList *); 142static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 143static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 144static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 145static void trace_loaded_objects(Obj_Entry *); 146static void unlink_object(Obj_Entry *); 147static void unload_object(Obj_Entry *); 148static void unref_dag(Obj_Entry *); 149static void ref_dag(Obj_Entry *); 150static char *origin_subst_one(char *, const char *, const char *, bool); 151static char *origin_subst(char *, const char *); 152static void preinit_main(void); 153static int rtld_verify_versions(const Objlist *); 154static int rtld_verify_object_versions(Obj_Entry *); 155static void object_add_name(Obj_Entry *, const char *); 156static int object_match_name(const Obj_Entry *, const char *); 157static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 158static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 159 struct dl_phdr_info *phdr_info); 160static uint32_t gnu_hash(const char *); 161static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 162 const unsigned long); 163 164void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported; 165void _r_debug_postinit(struct link_map *) __noinline __exported; 166 167/* 168 * Data declarations. 169 */ 170static char *error_message; /* Message for dlerror(), or NULL */ 171struct r_debug r_debug __exported; /* for GDB; */ 172static bool libmap_disable; /* Disable libmap */ 173static bool ld_loadfltr; /* Immediate filters processing */ 174static char *libmap_override; /* Maps to use in addition to libmap.conf */ 175static bool trust; /* False for setuid and setgid programs */ 176static bool dangerous_ld_env; /* True if environment variables have been 177 used to affect the libraries loaded */ 178static char *ld_bind_now; /* Environment variable for immediate binding */ 179static char *ld_debug; /* Environment variable for debugging */ 180static char *ld_library_path; /* Environment variable for search path */ 181static char *ld_preload; /* Environment variable for libraries to 182 load first */ 183static char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 184static char *ld_tracing; /* Called from ldd to print libs */ 185static char *ld_utrace; /* Use utrace() to log events. */ 186static Obj_Entry *obj_list; /* Head of linked list of shared objects */ 187static Obj_Entry **obj_tail; /* Link field of last object in list */ 188static Obj_Entry *obj_main; /* The main program shared object */ 189static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 190static unsigned int obj_count; /* Number of objects in obj_list */ 191static unsigned int obj_loads; /* Number of objects in obj_list */ 192 193static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 194 STAILQ_HEAD_INITIALIZER(list_global); 195static Objlist list_main = /* Objects loaded at program startup */ 196 STAILQ_HEAD_INITIALIZER(list_main); 197static Objlist list_fini = /* Objects needing fini() calls */ 198 STAILQ_HEAD_INITIALIZER(list_fini); 199 200Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 201 202#define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 203 204extern Elf_Dyn _DYNAMIC; 205#pragma weak _DYNAMIC 206#ifndef RTLD_IS_DYNAMIC 207#define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL) 208#endif 209 210int dlclose(void *) __exported; 211char *dlerror(void) __exported; 212void *dlopen(const char *, int) __exported; 213void *fdlopen(int, int) __exported; 214void *dlsym(void *, const char *) __exported; 215dlfunc_t dlfunc(void *, const char *) __exported; 216void *dlvsym(void *, const char *, const char *) __exported; 217int dladdr(const void *, Dl_info *) __exported; 218void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *), 219 void (*)(void *), void (*)(void *), void (*)(void *)) __exported; 220int dlinfo(void *, int , void *) __exported; 221int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported; 222int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported; 223int _rtld_get_stack_prot(void) __exported; 224int _rtld_is_dlopened(void *) __exported; 225void _rtld_error(const char *, ...) __exported; 226 227int npagesizes, osreldate; 228size_t *pagesizes; 229 230long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0}; 231 232static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 233static int max_stack_flags; 234 235/* 236 * Global declarations normally provided by crt1. The dynamic linker is 237 * not built with crt1, so we have to provide them ourselves. 238 */ 239char *__progname; 240char **environ; 241 242/* 243 * Used to pass argc, argv to init functions. 244 */ 245int main_argc; 246char **main_argv; 247 248/* 249 * Globals to control TLS allocation. 250 */ 251size_t tls_last_offset; /* Static TLS offset of last module */ 252size_t tls_last_size; /* Static TLS size of last module */ 253size_t tls_static_space; /* Static TLS space allocated */ 254size_t tls_static_max_align; 255int tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 256int tls_max_index = 1; /* Largest module index allocated */ 257 258bool ld_library_path_rpath = false; 259 260/* 261 * Fill in a DoneList with an allocation large enough to hold all of 262 * the currently-loaded objects. Keep this as a macro since it calls 263 * alloca and we want that to occur within the scope of the caller. 264 */ 265#define donelist_init(dlp) \ 266 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 267 assert((dlp)->objs != NULL), \ 268 (dlp)->num_alloc = obj_count, \ 269 (dlp)->num_used = 0) 270 271#define UTRACE_DLOPEN_START 1 272#define UTRACE_DLOPEN_STOP 2 273#define UTRACE_DLCLOSE_START 3 274#define UTRACE_DLCLOSE_STOP 4 275#define UTRACE_LOAD_OBJECT 5 276#define UTRACE_UNLOAD_OBJECT 6 277#define UTRACE_ADD_RUNDEP 7 278#define UTRACE_PRELOAD_FINISHED 8 279#define UTRACE_INIT_CALL 9 280#define UTRACE_FINI_CALL 10 281 282struct utrace_rtld { 283 char sig[4]; /* 'RTLD' */ 284 int event; 285 void *handle; 286 void *mapbase; /* Used for 'parent' and 'init/fini' */ 287 size_t mapsize; 288 int refcnt; /* Used for 'mode' */ 289 char name[MAXPATHLEN]; 290}; 291 292#define LD_UTRACE(e, h, mb, ms, r, n) do { \ 293 if (ld_utrace != NULL) \ 294 ld_utrace_log(e, h, mb, ms, r, n); \ 295} while (0) 296 297static void 298ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 299 int refcnt, const char *name) 300{ 301 struct utrace_rtld ut; 302 303 ut.sig[0] = 'R'; 304 ut.sig[1] = 'T'; 305 ut.sig[2] = 'L'; 306 ut.sig[3] = 'D'; 307 ut.event = event; 308 ut.handle = handle; 309 ut.mapbase = mapbase; 310 ut.mapsize = mapsize; 311 ut.refcnt = refcnt; 312 bzero(ut.name, sizeof(ut.name)); 313 if (name) 314 strlcpy(ut.name, name, sizeof(ut.name)); 315 utrace(&ut, sizeof(ut)); 316} 317 318/* 319 * Main entry point for dynamic linking. The first argument is the 320 * stack pointer. The stack is expected to be laid out as described 321 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 322 * Specifically, the stack pointer points to a word containing 323 * ARGC. Following that in the stack is a null-terminated sequence 324 * of pointers to argument strings. Then comes a null-terminated 325 * sequence of pointers to environment strings. Finally, there is a 326 * sequence of "auxiliary vector" entries. 327 * 328 * The second argument points to a place to store the dynamic linker's 329 * exit procedure pointer and the third to a place to store the main 330 * program's object. 331 * 332 * The return value is the main program's entry point. 333 */ 334func_ptr_type 335_rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 336{ 337 Elf_Auxinfo *aux_info[AT_COUNT]; 338 int i; 339 int argc; 340 char **argv; 341 char **env; 342 Elf_Auxinfo *aux; 343 Elf_Auxinfo *auxp; 344 const char *argv0; 345 Objlist_Entry *entry; 346 Obj_Entry *obj; 347 Obj_Entry **preload_tail; 348 Obj_Entry *last_interposer; 349 Objlist initlist; 350 RtldLockState lockstate; 351 char *library_path_rpath; 352 int mib[2]; 353 size_t len; 354 355 /* 356 * On entry, the dynamic linker itself has not been relocated yet. 357 * Be very careful not to reference any global data until after 358 * init_rtld has returned. It is OK to reference file-scope statics 359 * and string constants, and to call static and global functions. 360 */ 361 362 /* Find the auxiliary vector on the stack. */ 363 argc = *sp++; 364 argv = (char **) sp; 365 sp += argc + 1; /* Skip over arguments and NULL terminator */ 366 env = (char **) sp; 367 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 368 ; 369 aux = (Elf_Auxinfo *) sp; 370 371 /* Digest the auxiliary vector. */ 372 for (i = 0; i < AT_COUNT; i++) 373 aux_info[i] = NULL; 374 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 375 if (auxp->a_type < AT_COUNT) 376 aux_info[auxp->a_type] = auxp; 377 } 378 379 /* Initialize and relocate ourselves. */ 380 assert(aux_info[AT_BASE] != NULL); 381 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 382 383 __progname = obj_rtld.path; 384 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 385 environ = env; 386 main_argc = argc; 387 main_argv = argv; 388 389 if (aux_info[AT_CANARY] != NULL && 390 aux_info[AT_CANARY]->a_un.a_ptr != NULL) { 391 i = aux_info[AT_CANARYLEN]->a_un.a_val; 392 if (i > sizeof(__stack_chk_guard)) 393 i = sizeof(__stack_chk_guard); 394 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i); 395 } else { 396 mib[0] = CTL_KERN; 397 mib[1] = KERN_ARND; 398 399 len = sizeof(__stack_chk_guard); 400 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 || 401 len != sizeof(__stack_chk_guard)) { 402 /* If sysctl was unsuccessful, use the "terminator canary". */ 403 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0; 404 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0; 405 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n'; 406 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255; 407 } 408 } 409 410 trust = !issetugid(); 411 412 ld_bind_now = getenv(LD_ "BIND_NOW"); 413 /* 414 * If the process is tainted, then we un-set the dangerous environment 415 * variables. The process will be marked as tainted until setuid(2) 416 * is called. If any child process calls setuid(2) we do not want any 417 * future processes to honor the potentially un-safe variables. 418 */ 419 if (!trust) { 420 if (unsetenv(LD_ "PRELOAD") || unsetenv(LD_ "LIBMAP") || 421 unsetenv(LD_ "LIBRARY_PATH") || unsetenv(LD_ "LIBMAP_DISABLE") || 422 unsetenv(LD_ "DEBUG") || unsetenv(LD_ "ELF_HINTS_PATH") || 423 unsetenv(LD_ "LOADFLTR") || unsetenv(LD_ "LIBRARY_PATH_RPATH")) { 424 _rtld_error("environment corrupt; aborting"); 425 die(); 426 } 427 } 428 ld_debug = getenv(LD_ "DEBUG"); 429 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL; 430 libmap_override = getenv(LD_ "LIBMAP"); 431 ld_library_path = getenv(LD_ "LIBRARY_PATH"); 432 ld_preload = getenv(LD_ "PRELOAD"); 433 ld_elf_hints_path = getenv(LD_ "ELF_HINTS_PATH"); 434 ld_loadfltr = getenv(LD_ "LOADFLTR") != NULL; 435 library_path_rpath = getenv(LD_ "LIBRARY_PATH_RPATH"); 436 if (library_path_rpath != NULL) { 437 if (library_path_rpath[0] == 'y' || 438 library_path_rpath[0] == 'Y' || 439 library_path_rpath[0] == '1') 440 ld_library_path_rpath = true; 441 else 442 ld_library_path_rpath = false; 443 } 444 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 445 (ld_library_path != NULL) || (ld_preload != NULL) || 446 (ld_elf_hints_path != NULL) || ld_loadfltr; 447 ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS"); 448 ld_utrace = getenv(LD_ "UTRACE"); 449 450 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 451 ld_elf_hints_path = _PATH_ELF_HINTS; 452 453 if (ld_debug != NULL && *ld_debug != '\0') 454 debug = 1; 455 dbg("%s is initialized, base address = %p", __progname, 456 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 457 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 458 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 459 460 dbg("initializing thread locks"); 461 lockdflt_init(); 462 463 /* 464 * Load the main program, or process its program header if it is 465 * already loaded. 466 */ 467 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */ 468 int fd = aux_info[AT_EXECFD]->a_un.a_val; 469 dbg("loading main program"); 470 obj_main = map_object(fd, argv0, NULL); 471 close(fd); 472 if (obj_main == NULL) 473 die(); 474 max_stack_flags = obj->stack_flags; 475 } else { /* Main program already loaded. */ 476 const Elf_Phdr *phdr; 477 int phnum; 478 caddr_t entry; 479 480 dbg("processing main program's program header"); 481 assert(aux_info[AT_PHDR] != NULL); 482 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 483 assert(aux_info[AT_PHNUM] != NULL); 484 phnum = aux_info[AT_PHNUM]->a_un.a_val; 485 assert(aux_info[AT_PHENT] != NULL); 486 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 487 assert(aux_info[AT_ENTRY] != NULL); 488 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 489 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL) 490 die(); 491 } 492 493 if (aux_info[AT_EXECPATH] != 0) { 494 char *kexecpath; 495 char buf[MAXPATHLEN]; 496 497 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 498 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 499 if (kexecpath[0] == '/') 500 obj_main->path = kexecpath; 501 else if (getcwd(buf, sizeof(buf)) == NULL || 502 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 503 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 504 obj_main->path = xstrdup(argv0); 505 else 506 obj_main->path = xstrdup(buf); 507 } else { 508 dbg("No AT_EXECPATH"); 509 obj_main->path = xstrdup(argv0); 510 } 511 dbg("obj_main path %s", obj_main->path); 512 obj_main->mainprog = true; 513 514 if (aux_info[AT_STACKPROT] != NULL && 515 aux_info[AT_STACKPROT]->a_un.a_val != 0) 516 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 517 518#ifndef COMPAT_32BIT 519 /* 520 * Get the actual dynamic linker pathname from the executable if 521 * possible. (It should always be possible.) That ensures that 522 * gdb will find the right dynamic linker even if a non-standard 523 * one is being used. 524 */ 525 if (obj_main->interp != NULL && 526 strcmp(obj_main->interp, obj_rtld.path) != 0) { 527 free(obj_rtld.path); 528 obj_rtld.path = xstrdup(obj_main->interp); 529 __progname = obj_rtld.path; 530 } 531#endif 532 533 digest_dynamic(obj_main, 0); 534 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 535 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 536 obj_main->dynsymcount); 537 538 linkmap_add(obj_main); 539 linkmap_add(&obj_rtld); 540 541 /* Link the main program into the list of objects. */ 542 *obj_tail = obj_main; 543 obj_tail = &obj_main->next; 544 obj_count++; 545 obj_loads++; 546 547 /* Initialize a fake symbol for resolving undefined weak references. */ 548 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 549 sym_zero.st_shndx = SHN_UNDEF; 550 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 551 552 if (!libmap_disable) 553 libmap_disable = (bool)lm_init(libmap_override); 554 555 dbg("loading LD_PRELOAD libraries"); 556 if (load_preload_objects() == -1) 557 die(); 558 preload_tail = obj_tail; 559 560 dbg("loading needed objects"); 561 if (load_needed_objects(obj_main, 0) == -1) 562 die(); 563 564 /* Make a list of all objects loaded at startup. */ 565 last_interposer = obj_main; 566 for (obj = obj_list; obj != NULL; obj = obj->next) { 567 if (obj->z_interpose && obj != obj_main) { 568 objlist_put_after(&list_main, last_interposer, obj); 569 last_interposer = obj; 570 } else { 571 objlist_push_tail(&list_main, obj); 572 } 573 obj->refcount++; 574 } 575 576 dbg("checking for required versions"); 577 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 578 die(); 579 580 if (ld_tracing) { /* We're done */ 581 trace_loaded_objects(obj_main); 582 exit(0); 583 } 584 585 if (getenv(LD_ "DUMP_REL_PRE") != NULL) { 586 dump_relocations(obj_main); 587 exit (0); 588 } 589 590 /* 591 * Processing tls relocations requires having the tls offsets 592 * initialized. Prepare offsets before starting initial 593 * relocation processing. 594 */ 595 dbg("initializing initial thread local storage offsets"); 596 STAILQ_FOREACH(entry, &list_main, link) { 597 /* 598 * Allocate all the initial objects out of the static TLS 599 * block even if they didn't ask for it. 600 */ 601 allocate_tls_offset(entry->obj); 602 } 603 604 if (relocate_objects(obj_main, 605 ld_bind_now != NULL && *ld_bind_now != '\0', 606 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 607 die(); 608 609 dbg("doing copy relocations"); 610 if (do_copy_relocations(obj_main) == -1) 611 die(); 612 613 if (getenv(LD_ "DUMP_REL_POST") != NULL) { 614 dump_relocations(obj_main); 615 exit (0); 616 } 617 618 /* 619 * Setup TLS for main thread. This must be done after the 620 * relocations are processed, since tls initialization section 621 * might be the subject for relocations. 622 */ 623 dbg("initializing initial thread local storage"); 624 allocate_initial_tls(obj_list); 625 626 dbg("initializing key program variables"); 627 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 628 set_program_var("environ", env); 629 set_program_var("__elf_aux_vector", aux); 630 631 /* Make a list of init functions to call. */ 632 objlist_init(&initlist); 633 initlist_add_objects(obj_list, preload_tail, &initlist); 634 635 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 636 637 map_stacks_exec(NULL); 638 639 dbg("resolving ifuncs"); 640 if (resolve_objects_ifunc(obj_main, 641 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY, 642 NULL) == -1) 643 die(); 644 645 if (!obj_main->crt_no_init) { 646 /* 647 * Make sure we don't call the main program's init and fini 648 * functions for binaries linked with old crt1 which calls 649 * _init itself. 650 */ 651 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 652 obj_main->preinit_array = obj_main->init_array = 653 obj_main->fini_array = (Elf_Addr)NULL; 654 } 655 656 wlock_acquire(rtld_bind_lock, &lockstate); 657 if (obj_main->crt_no_init) 658 preinit_main(); 659 objlist_call_init(&initlist, &lockstate); 660 _r_debug_postinit(&obj_main->linkmap); 661 objlist_clear(&initlist); 662 dbg("loading filtees"); 663 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 664 if (ld_loadfltr || obj->z_loadfltr) 665 load_filtees(obj, 0, &lockstate); 666 } 667 lock_release(rtld_bind_lock, &lockstate); 668 669 dbg("transferring control to program entry point = %p", obj_main->entry); 670 671 /* Return the exit procedure and the program entry point. */ 672 *exit_proc = rtld_exit; 673 *objp = obj_main; 674 return (func_ptr_type) obj_main->entry; 675} 676 677void * 678rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 679{ 680 void *ptr; 681 Elf_Addr target; 682 683 ptr = (void *)make_function_pointer(def, obj); 684 target = ((Elf_Addr (*)(void))ptr)(); 685 return ((void *)target); 686} 687 688Elf_Addr 689_rtld_bind(Obj_Entry *obj, Elf_Size reloff) 690{ 691 const Elf_Rel *rel; 692 const Elf_Sym *def; 693 const Obj_Entry *defobj; 694 Elf_Addr *where; 695 Elf_Addr target; 696 RtldLockState lockstate; 697 698 rlock_acquire(rtld_bind_lock, &lockstate); 699 if (sigsetjmp(lockstate.env, 0) != 0) 700 lock_upgrade(rtld_bind_lock, &lockstate); 701 if (obj->pltrel) 702 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 703 else 704 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 705 706 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 707 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL, 708 &lockstate); 709 if (def == NULL) 710 die(); 711 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 712 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 713 else 714 target = (Elf_Addr)(defobj->relocbase + def->st_value); 715 716 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 717 defobj->strtab + def->st_name, basename(obj->path), 718 (void *)target, basename(defobj->path)); 719 720 /* 721 * Write the new contents for the jmpslot. Note that depending on 722 * architecture, the value which we need to return back to the 723 * lazy binding trampoline may or may not be the target 724 * address. The value returned from reloc_jmpslot() is the value 725 * that the trampoline needs. 726 */ 727 target = reloc_jmpslot(where, target, defobj, obj, rel); 728 lock_release(rtld_bind_lock, &lockstate); 729 return target; 730} 731 732/* 733 * Error reporting function. Use it like printf. If formats the message 734 * into a buffer, and sets things up so that the next call to dlerror() 735 * will return the message. 736 */ 737void 738_rtld_error(const char *fmt, ...) 739{ 740 static char buf[512]; 741 va_list ap; 742 743 va_start(ap, fmt); 744 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 745 error_message = buf; 746 va_end(ap); 747} 748 749/* 750 * Return a dynamically-allocated copy of the current error message, if any. 751 */ 752static char * 753errmsg_save(void) 754{ 755 return error_message == NULL ? NULL : xstrdup(error_message); 756} 757 758/* 759 * Restore the current error message from a copy which was previously saved 760 * by errmsg_save(). The copy is freed. 761 */ 762static void 763errmsg_restore(char *saved_msg) 764{ 765 if (saved_msg == NULL) 766 error_message = NULL; 767 else { 768 _rtld_error("%s", saved_msg); 769 free(saved_msg); 770 } 771} 772 773static const char * 774basename(const char *name) 775{ 776 const char *p = strrchr(name, '/'); 777 return p != NULL ? p + 1 : name; 778} 779 780static struct utsname uts; 781 782static char * 783origin_subst_one(char *real, const char *kw, const char *subst, 784 bool may_free) 785{ 786 char *p, *p1, *res, *resp; 787 int subst_len, kw_len, subst_count, old_len, new_len; 788 789 kw_len = strlen(kw); 790 791 /* 792 * First, count the number of the keyword occurences, to 793 * preallocate the final string. 794 */ 795 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 796 p1 = strstr(p, kw); 797 if (p1 == NULL) 798 break; 799 } 800 801 /* 802 * If the keyword is not found, just return. 803 */ 804 if (subst_count == 0) 805 return (may_free ? real : xstrdup(real)); 806 807 /* 808 * There is indeed something to substitute. Calculate the 809 * length of the resulting string, and allocate it. 810 */ 811 subst_len = strlen(subst); 812 old_len = strlen(real); 813 new_len = old_len + (subst_len - kw_len) * subst_count; 814 res = xmalloc(new_len + 1); 815 816 /* 817 * Now, execute the substitution loop. 818 */ 819 for (p = real, resp = res, *resp = '\0';;) { 820 p1 = strstr(p, kw); 821 if (p1 != NULL) { 822 /* Copy the prefix before keyword. */ 823 memcpy(resp, p, p1 - p); 824 resp += p1 - p; 825 /* Keyword replacement. */ 826 memcpy(resp, subst, subst_len); 827 resp += subst_len; 828 *resp = '\0'; 829 p = p1 + kw_len; 830 } else 831 break; 832 } 833 834 /* Copy to the end of string and finish. */ 835 strcat(resp, p); 836 if (may_free) 837 free(real); 838 return (res); 839} 840 841static char * 842origin_subst(char *real, const char *origin_path) 843{ 844 char *res1, *res2, *res3, *res4; 845 846 if (uts.sysname[0] == '\0') { 847 if (uname(&uts) != 0) { 848 _rtld_error("utsname failed: %d", errno); 849 return (NULL); 850 } 851 } 852 res1 = origin_subst_one(real, "$ORIGIN", origin_path, false); 853 res2 = origin_subst_one(res1, "$OSNAME", uts.sysname, true); 854 res3 = origin_subst_one(res2, "$OSREL", uts.release, true); 855 res4 = origin_subst_one(res3, "$PLATFORM", uts.machine, true); 856 return (res4); 857} 858 859static void 860die(void) 861{ 862 const char *msg = dlerror(); 863 864 if (msg == NULL) 865 msg = "Fatal error"; 866 rtld_fdputstr(STDERR_FILENO, msg); 867 rtld_fdputchar(STDERR_FILENO, '\n'); 868 _exit(1); 869} 870 871/* 872 * Process a shared object's DYNAMIC section, and save the important 873 * information in its Obj_Entry structure. 874 */ 875static void 876digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 877 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 878{ 879 const Elf_Dyn *dynp; 880 Needed_Entry **needed_tail = &obj->needed; 881 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 882 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 883 const Elf_Hashelt *hashtab; 884 const Elf32_Word *hashval; 885 Elf32_Word bkt, nmaskwords; 886 int bloom_size32; 887 int plttype = DT_REL; 888 889 *dyn_rpath = NULL; 890 *dyn_soname = NULL; 891 *dyn_runpath = NULL; 892 893 obj->bind_now = false; 894 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 895 switch (dynp->d_tag) { 896 897 case DT_REL: 898 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 899 break; 900 901 case DT_RELSZ: 902 obj->relsize = dynp->d_un.d_val; 903 break; 904 905 case DT_RELENT: 906 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 907 break; 908 909 case DT_JMPREL: 910 obj->pltrel = (const Elf_Rel *) 911 (obj->relocbase + dynp->d_un.d_ptr); 912 break; 913 914 case DT_PLTRELSZ: 915 obj->pltrelsize = dynp->d_un.d_val; 916 break; 917 918 case DT_RELA: 919 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 920 break; 921 922 case DT_RELASZ: 923 obj->relasize = dynp->d_un.d_val; 924 break; 925 926 case DT_RELAENT: 927 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 928 break; 929 930 case DT_PLTREL: 931 plttype = dynp->d_un.d_val; 932 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 933 break; 934 935 case DT_SYMTAB: 936 obj->symtab = (const Elf_Sym *) 937 (obj->relocbase + dynp->d_un.d_ptr); 938 break; 939 940 case DT_SYMENT: 941 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 942 break; 943 944 case DT_STRTAB: 945 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 946 break; 947 948 case DT_STRSZ: 949 obj->strsize = dynp->d_un.d_val; 950 break; 951 952 case DT_VERNEED: 953 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 954 dynp->d_un.d_val); 955 break; 956 957 case DT_VERNEEDNUM: 958 obj->verneednum = dynp->d_un.d_val; 959 break; 960 961 case DT_VERDEF: 962 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 963 dynp->d_un.d_val); 964 break; 965 966 case DT_VERDEFNUM: 967 obj->verdefnum = dynp->d_un.d_val; 968 break; 969 970 case DT_VERSYM: 971 obj->versyms = (const Elf_Versym *)(obj->relocbase + 972 dynp->d_un.d_val); 973 break; 974 975 case DT_HASH: 976 { 977 hashtab = (const Elf_Hashelt *)(obj->relocbase + 978 dynp->d_un.d_ptr); 979 obj->nbuckets = hashtab[0]; 980 obj->nchains = hashtab[1]; 981 obj->buckets = hashtab + 2; 982 obj->chains = obj->buckets + obj->nbuckets; 983 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 984 obj->buckets != NULL; 985 } 986 break; 987 988 case DT_GNU_HASH: 989 { 990 hashtab = (const Elf_Hashelt *)(obj->relocbase + 991 dynp->d_un.d_ptr); 992 obj->nbuckets_gnu = hashtab[0]; 993 obj->symndx_gnu = hashtab[1]; 994 nmaskwords = hashtab[2]; 995 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 996 obj->maskwords_bm_gnu = nmaskwords - 1; 997 obj->shift2_gnu = hashtab[3]; 998 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4); 999 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1000 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1001 obj->symndx_gnu; 1002 /* Number of bitmask words is required to be power of 2 */ 1003 obj->valid_hash_gnu = powerof2(nmaskwords) && 1004 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1005 } 1006 break; 1007 1008 case DT_NEEDED: 1009 if (!obj->rtld) { 1010 Needed_Entry *nep = NEW(Needed_Entry); 1011 nep->name = dynp->d_un.d_val; 1012 nep->obj = NULL; 1013 nep->next = NULL; 1014 1015 *needed_tail = nep; 1016 needed_tail = &nep->next; 1017 } 1018 break; 1019 1020 case DT_FILTER: 1021 if (!obj->rtld) { 1022 Needed_Entry *nep = NEW(Needed_Entry); 1023 nep->name = dynp->d_un.d_val; 1024 nep->obj = NULL; 1025 nep->next = NULL; 1026 1027 *needed_filtees_tail = nep; 1028 needed_filtees_tail = &nep->next; 1029 } 1030 break; 1031 1032 case DT_AUXILIARY: 1033 if (!obj->rtld) { 1034 Needed_Entry *nep = NEW(Needed_Entry); 1035 nep->name = dynp->d_un.d_val; 1036 nep->obj = NULL; 1037 nep->next = NULL; 1038 1039 *needed_aux_filtees_tail = nep; 1040 needed_aux_filtees_tail = &nep->next; 1041 } 1042 break; 1043 1044 case DT_PLTGOT: 1045 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 1046 break; 1047 1048 case DT_TEXTREL: 1049 obj->textrel = true; 1050 break; 1051 1052 case DT_SYMBOLIC: 1053 obj->symbolic = true; 1054 break; 1055 1056 case DT_RPATH: 1057 /* 1058 * We have to wait until later to process this, because we 1059 * might not have gotten the address of the string table yet. 1060 */ 1061 *dyn_rpath = dynp; 1062 break; 1063 1064 case DT_SONAME: 1065 *dyn_soname = dynp; 1066 break; 1067 1068 case DT_RUNPATH: 1069 *dyn_runpath = dynp; 1070 break; 1071 1072 case DT_INIT: 1073 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1074 break; 1075 1076 case DT_PREINIT_ARRAY: 1077 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1078 break; 1079 1080 case DT_PREINIT_ARRAYSZ: 1081 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1082 break; 1083 1084 case DT_INIT_ARRAY: 1085 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1086 break; 1087 1088 case DT_INIT_ARRAYSZ: 1089 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1090 break; 1091 1092 case DT_FINI: 1093 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1094 break; 1095 1096 case DT_FINI_ARRAY: 1097 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1098 break; 1099 1100 case DT_FINI_ARRAYSZ: 1101 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1102 break; 1103 1104 /* 1105 * Don't process DT_DEBUG on MIPS as the dynamic section 1106 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1107 */ 1108 1109#ifndef __mips__ 1110 case DT_DEBUG: 1111 /* XXX - not implemented yet */ 1112 if (!early) 1113 dbg("Filling in DT_DEBUG entry"); 1114 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 1115 break; 1116#endif 1117 1118 case DT_FLAGS: 1119 if ((dynp->d_un.d_val & DF_ORIGIN) && trust) 1120 obj->z_origin = true; 1121 if (dynp->d_un.d_val & DF_SYMBOLIC) 1122 obj->symbolic = true; 1123 if (dynp->d_un.d_val & DF_TEXTREL) 1124 obj->textrel = true; 1125 if (dynp->d_un.d_val & DF_BIND_NOW) 1126 obj->bind_now = true; 1127 /*if (dynp->d_un.d_val & DF_STATIC_TLS) 1128 ;*/ 1129 break; 1130#ifdef __mips__ 1131 case DT_MIPS_LOCAL_GOTNO: 1132 obj->local_gotno = dynp->d_un.d_val; 1133 break; 1134 1135 case DT_MIPS_SYMTABNO: 1136 obj->symtabno = dynp->d_un.d_val; 1137 break; 1138 1139 case DT_MIPS_GOTSYM: 1140 obj->gotsym = dynp->d_un.d_val; 1141 break; 1142 1143 case DT_MIPS_RLD_MAP: 1144 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1145 break; 1146#endif 1147 1148 case DT_FLAGS_1: 1149 if (dynp->d_un.d_val & DF_1_NOOPEN) 1150 obj->z_noopen = true; 1151 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust) 1152 obj->z_origin = true; 1153 /*if (dynp->d_un.d_val & DF_1_GLOBAL) 1154 XXX ;*/ 1155 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1156 obj->bind_now = true; 1157 if (dynp->d_un.d_val & DF_1_NODELETE) 1158 obj->z_nodelete = true; 1159 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1160 obj->z_loadfltr = true; 1161 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1162 obj->z_interpose = true; 1163 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1164 obj->z_nodeflib = true; 1165 break; 1166 1167 default: 1168 if (!early) { 1169 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1170 (long)dynp->d_tag); 1171 } 1172 break; 1173 } 1174 } 1175 1176 obj->traced = false; 1177 1178 if (plttype == DT_RELA) { 1179 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1180 obj->pltrel = NULL; 1181 obj->pltrelasize = obj->pltrelsize; 1182 obj->pltrelsize = 0; 1183 } 1184 1185 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1186 if (obj->valid_hash_sysv) 1187 obj->dynsymcount = obj->nchains; 1188 else if (obj->valid_hash_gnu) { 1189 obj->dynsymcount = 0; 1190 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1191 if (obj->buckets_gnu[bkt] == 0) 1192 continue; 1193 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1194 do 1195 obj->dynsymcount++; 1196 while ((*hashval++ & 1u) == 0); 1197 } 1198 obj->dynsymcount += obj->symndx_gnu; 1199 } 1200} 1201 1202static void 1203digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1204 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1205{ 1206 1207 if (obj->z_origin && obj->origin_path == NULL) { 1208 obj->origin_path = xmalloc(PATH_MAX); 1209 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1) 1210 die(); 1211 } 1212 1213 if (dyn_runpath != NULL) { 1214 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val; 1215 if (obj->z_origin) 1216 obj->runpath = origin_subst(obj->runpath, obj->origin_path); 1217 } 1218 else if (dyn_rpath != NULL) { 1219 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 1220 if (obj->z_origin) 1221 obj->rpath = origin_subst(obj->rpath, obj->origin_path); 1222 } 1223 1224 if (dyn_soname != NULL) 1225 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1226} 1227 1228static void 1229digest_dynamic(Obj_Entry *obj, int early) 1230{ 1231 const Elf_Dyn *dyn_rpath; 1232 const Elf_Dyn *dyn_soname; 1233 const Elf_Dyn *dyn_runpath; 1234 1235 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1236 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath); 1237} 1238 1239/* 1240 * Process a shared object's program header. This is used only for the 1241 * main program, when the kernel has already loaded the main program 1242 * into memory before calling the dynamic linker. It creates and 1243 * returns an Obj_Entry structure. 1244 */ 1245static Obj_Entry * 1246digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1247{ 1248 Obj_Entry *obj; 1249 const Elf_Phdr *phlimit = phdr + phnum; 1250 const Elf_Phdr *ph; 1251 Elf_Addr note_start, note_end; 1252 int nsegs = 0; 1253 1254 obj = obj_new(); 1255 for (ph = phdr; ph < phlimit; ph++) { 1256 if (ph->p_type != PT_PHDR) 1257 continue; 1258 1259 obj->phdr = phdr; 1260 obj->phsize = ph->p_memsz; 1261 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1262 break; 1263 } 1264 1265 obj->stack_flags = PF_X | PF_R | PF_W; 1266 1267 for (ph = phdr; ph < phlimit; ph++) { 1268 switch (ph->p_type) { 1269 1270 case PT_INTERP: 1271 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1272 break; 1273 1274 case PT_LOAD: 1275 if (nsegs == 0) { /* First load segment */ 1276 obj->vaddrbase = trunc_page(ph->p_vaddr); 1277 obj->mapbase = obj->vaddrbase + obj->relocbase; 1278 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1279 obj->vaddrbase; 1280 } else { /* Last load segment */ 1281 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1282 obj->vaddrbase; 1283 } 1284 nsegs++; 1285 break; 1286 1287 case PT_DYNAMIC: 1288 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1289 break; 1290 1291 case PT_TLS: 1292 obj->tlsindex = 1; 1293 obj->tlssize = ph->p_memsz; 1294 obj->tlsalign = ph->p_align; 1295 obj->tlsinitsize = ph->p_filesz; 1296 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1297 break; 1298 1299 case PT_GNU_STACK: 1300 obj->stack_flags = ph->p_flags; 1301 break; 1302 1303 case PT_GNU_RELRO: 1304 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1305 obj->relro_size = round_page(ph->p_memsz); 1306 break; 1307 1308 case PT_NOTE: 1309 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1310 note_end = note_start + ph->p_filesz; 1311 digest_notes(obj, note_start, note_end); 1312 break; 1313 } 1314 } 1315 if (nsegs < 1) { 1316 _rtld_error("%s: too few PT_LOAD segments", path); 1317 return NULL; 1318 } 1319 1320 obj->entry = entry; 1321 return obj; 1322} 1323 1324void 1325digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1326{ 1327 const Elf_Note *note; 1328 const char *note_name; 1329 uintptr_t p; 1330 1331 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1332 note = (const Elf_Note *)((const char *)(note + 1) + 1333 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1334 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1335 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1336 note->n_descsz != sizeof(int32_t)) 1337 continue; 1338 if (note->n_type != ABI_NOTETYPE && 1339 note->n_type != CRT_NOINIT_NOTETYPE) 1340 continue; 1341 note_name = (const char *)(note + 1); 1342 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1343 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1344 continue; 1345 switch (note->n_type) { 1346 case ABI_NOTETYPE: 1347 /* FreeBSD osrel note */ 1348 p = (uintptr_t)(note + 1); 1349 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1350 obj->osrel = *(const int32_t *)(p); 1351 dbg("note osrel %d", obj->osrel); 1352 break; 1353 case CRT_NOINIT_NOTETYPE: 1354 /* FreeBSD 'crt does not call init' note */ 1355 obj->crt_no_init = true; 1356 dbg("note crt_no_init"); 1357 break; 1358 } 1359 } 1360} 1361 1362static Obj_Entry * 1363dlcheck(void *handle) 1364{ 1365 Obj_Entry *obj; 1366 1367 for (obj = obj_list; obj != NULL; obj = obj->next) 1368 if (obj == (Obj_Entry *) handle) 1369 break; 1370 1371 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1372 _rtld_error("Invalid shared object handle %p", handle); 1373 return NULL; 1374 } 1375 return obj; 1376} 1377 1378/* 1379 * If the given object is already in the donelist, return true. Otherwise 1380 * add the object to the list and return false. 1381 */ 1382static bool 1383donelist_check(DoneList *dlp, const Obj_Entry *obj) 1384{ 1385 unsigned int i; 1386 1387 for (i = 0; i < dlp->num_used; i++) 1388 if (dlp->objs[i] == obj) 1389 return true; 1390 /* 1391 * Our donelist allocation should always be sufficient. But if 1392 * our threads locking isn't working properly, more shared objects 1393 * could have been loaded since we allocated the list. That should 1394 * never happen, but we'll handle it properly just in case it does. 1395 */ 1396 if (dlp->num_used < dlp->num_alloc) 1397 dlp->objs[dlp->num_used++] = obj; 1398 return false; 1399} 1400 1401/* 1402 * Hash function for symbol table lookup. Don't even think about changing 1403 * this. It is specified by the System V ABI. 1404 */ 1405unsigned long 1406elf_hash(const char *name) 1407{ 1408 const unsigned char *p = (const unsigned char *) name; 1409 unsigned long h = 0; 1410 unsigned long g; 1411 1412 while (*p != '\0') { 1413 h = (h << 4) + *p++; 1414 if ((g = h & 0xf0000000) != 0) 1415 h ^= g >> 24; 1416 h &= ~g; 1417 } 1418 return h; 1419} 1420 1421/* 1422 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1423 * unsigned in case it's implemented with a wider type. 1424 */ 1425static uint32_t 1426gnu_hash(const char *s) 1427{ 1428 uint32_t h; 1429 unsigned char c; 1430 1431 h = 5381; 1432 for (c = *s; c != '\0'; c = *++s) 1433 h = h * 33 + c; 1434 return (h & 0xffffffff); 1435} 1436 1437/* 1438 * Find the library with the given name, and return its full pathname. 1439 * The returned string is dynamically allocated. Generates an error 1440 * message and returns NULL if the library cannot be found. 1441 * 1442 * If the second argument is non-NULL, then it refers to an already- 1443 * loaded shared object, whose library search path will be searched. 1444 * 1445 * The search order is: 1446 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1447 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1448 * LD_LIBRARY_PATH 1449 * DT_RUNPATH in the referencing file 1450 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1451 * from list) 1452 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1453 * 1454 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1455 */ 1456static char * 1457find_library(const char *xname, const Obj_Entry *refobj) 1458{ 1459 char *pathname; 1460 char *name; 1461 bool nodeflib, objgiven; 1462 1463 objgiven = refobj != NULL; 1464 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */ 1465 if (xname[0] != '/' && !trust) { 1466 _rtld_error("Absolute pathname required for shared object \"%s\"", 1467 xname); 1468 return NULL; 1469 } 1470 if (objgiven && refobj->z_origin) { 1471 return (origin_subst(__DECONST(char *, xname), 1472 refobj->origin_path)); 1473 } else { 1474 return (xstrdup(xname)); 1475 } 1476 } 1477 1478 if (libmap_disable || !objgiven || 1479 (name = lm_find(refobj->path, xname)) == NULL) 1480 name = (char *)xname; 1481 1482 dbg(" Searching for \"%s\"", name); 1483 1484 /* 1485 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1486 * back to pre-conforming behaviour if user requested so with 1487 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1488 * nodeflib. 1489 */ 1490 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1491 if ((pathname = search_library_path(name, ld_library_path)) != NULL || 1492 (refobj != NULL && 1493 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1494 (pathname = search_library_path(name, gethints(false))) != NULL || 1495 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL) 1496 return (pathname); 1497 } else { 1498 nodeflib = objgiven ? refobj->z_nodeflib : false; 1499 if ((objgiven && 1500 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1501 (objgiven && refobj->runpath == NULL && refobj != obj_main && 1502 (pathname = search_library_path(name, obj_main->rpath)) != NULL) || 1503 (pathname = search_library_path(name, ld_library_path)) != NULL || 1504 (objgiven && 1505 (pathname = search_library_path(name, refobj->runpath)) != NULL) || 1506 (pathname = search_library_path(name, gethints(nodeflib))) != NULL || 1507 (objgiven && !nodeflib && 1508 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)) 1509 return (pathname); 1510 } 1511 1512 if (objgiven && refobj->path != NULL) { 1513 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 1514 name, basename(refobj->path)); 1515 } else { 1516 _rtld_error("Shared object \"%s\" not found", name); 1517 } 1518 return NULL; 1519} 1520 1521/* 1522 * Given a symbol number in a referencing object, find the corresponding 1523 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1524 * no definition was found. Returns a pointer to the Obj_Entry of the 1525 * defining object via the reference parameter DEFOBJ_OUT. 1526 */ 1527const Elf_Sym * 1528find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1529 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1530 RtldLockState *lockstate) 1531{ 1532 const Elf_Sym *ref; 1533 const Elf_Sym *def; 1534 const Obj_Entry *defobj; 1535 SymLook req; 1536 const char *name; 1537 int res; 1538 1539 /* 1540 * If we have already found this symbol, get the information from 1541 * the cache. 1542 */ 1543 if (symnum >= refobj->dynsymcount) 1544 return NULL; /* Bad object */ 1545 if (cache != NULL && cache[symnum].sym != NULL) { 1546 *defobj_out = cache[symnum].obj; 1547 return cache[symnum].sym; 1548 } 1549 1550 ref = refobj->symtab + symnum; 1551 name = refobj->strtab + ref->st_name; 1552 def = NULL; 1553 defobj = NULL; 1554 1555 /* 1556 * We don't have to do a full scale lookup if the symbol is local. 1557 * We know it will bind to the instance in this load module; to 1558 * which we already have a pointer (ie ref). By not doing a lookup, 1559 * we not only improve performance, but it also avoids unresolvable 1560 * symbols when local symbols are not in the hash table. This has 1561 * been seen with the ia64 toolchain. 1562 */ 1563 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1564 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1565 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1566 symnum); 1567 } 1568 symlook_init(&req, name); 1569 req.flags = flags; 1570 req.ventry = fetch_ventry(refobj, symnum); 1571 req.lockstate = lockstate; 1572 res = symlook_default(&req, refobj); 1573 if (res == 0) { 1574 def = req.sym_out; 1575 defobj = req.defobj_out; 1576 } 1577 } else { 1578 def = ref; 1579 defobj = refobj; 1580 } 1581 1582 /* 1583 * If we found no definition and the reference is weak, treat the 1584 * symbol as having the value zero. 1585 */ 1586 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1587 def = &sym_zero; 1588 defobj = obj_main; 1589 } 1590 1591 if (def != NULL) { 1592 *defobj_out = defobj; 1593 /* Record the information in the cache to avoid subsequent lookups. */ 1594 if (cache != NULL) { 1595 cache[symnum].sym = def; 1596 cache[symnum].obj = defobj; 1597 } 1598 } else { 1599 if (refobj != &obj_rtld) 1600 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name); 1601 } 1602 return def; 1603} 1604 1605/* 1606 * Return the search path from the ldconfig hints file, reading it if 1607 * necessary. If nostdlib is true, then the default search paths are 1608 * not added to result. 1609 * 1610 * Returns NULL if there are problems with the hints file, 1611 * or if the search path there is empty. 1612 */ 1613static const char * 1614gethints(bool nostdlib) 1615{ 1616 static char *hints, *filtered_path; 1617 struct elfhints_hdr hdr; 1618 struct fill_search_info_args sargs, hargs; 1619 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1620 struct dl_serpath *SLPpath, *hintpath; 1621 char *p; 1622 unsigned int SLPndx, hintndx, fndx, fcount; 1623 int fd; 1624 size_t flen; 1625 bool skip; 1626 1627 /* First call, read the hints file */ 1628 if (hints == NULL) { 1629 /* Keep from trying again in case the hints file is bad. */ 1630 hints = ""; 1631 1632 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1633 return (NULL); 1634 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1635 hdr.magic != ELFHINTS_MAGIC || 1636 hdr.version != 1) { 1637 close(fd); 1638 return (NULL); 1639 } 1640 p = xmalloc(hdr.dirlistlen + 1); 1641 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1642 read(fd, p, hdr.dirlistlen + 1) != 1643 (ssize_t)hdr.dirlistlen + 1) { 1644 free(p); 1645 close(fd); 1646 return (NULL); 1647 } 1648 hints = p; 1649 close(fd); 1650 } 1651 1652 /* 1653 * If caller agreed to receive list which includes the default 1654 * paths, we are done. Otherwise, if we still did not 1655 * calculated filtered result, do it now. 1656 */ 1657 if (!nostdlib) 1658 return (hints[0] != '\0' ? hints : NULL); 1659 if (filtered_path != NULL) 1660 goto filt_ret; 1661 1662 /* 1663 * Obtain the list of all configured search paths, and the 1664 * list of the default paths. 1665 * 1666 * First estimate the size of the results. 1667 */ 1668 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1669 smeta.dls_cnt = 0; 1670 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1671 hmeta.dls_cnt = 0; 1672 1673 sargs.request = RTLD_DI_SERINFOSIZE; 1674 sargs.serinfo = &smeta; 1675 hargs.request = RTLD_DI_SERINFOSIZE; 1676 hargs.serinfo = &hmeta; 1677 1678 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1679 path_enumerate(p, fill_search_info, &hargs); 1680 1681 SLPinfo = xmalloc(smeta.dls_size); 1682 hintinfo = xmalloc(hmeta.dls_size); 1683 1684 /* 1685 * Next fetch both sets of paths. 1686 */ 1687 sargs.request = RTLD_DI_SERINFO; 1688 sargs.serinfo = SLPinfo; 1689 sargs.serpath = &SLPinfo->dls_serpath[0]; 1690 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1691 1692 hargs.request = RTLD_DI_SERINFO; 1693 hargs.serinfo = hintinfo; 1694 hargs.serpath = &hintinfo->dls_serpath[0]; 1695 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1696 1697 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1698 path_enumerate(p, fill_search_info, &hargs); 1699 1700 /* 1701 * Now calculate the difference between two sets, by excluding 1702 * standard paths from the full set. 1703 */ 1704 fndx = 0; 1705 fcount = 0; 1706 filtered_path = xmalloc(hdr.dirlistlen + 1); 1707 hintpath = &hintinfo->dls_serpath[0]; 1708 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1709 skip = false; 1710 SLPpath = &SLPinfo->dls_serpath[0]; 1711 /* 1712 * Check each standard path against current. 1713 */ 1714 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1715 /* matched, skip the path */ 1716 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1717 skip = true; 1718 break; 1719 } 1720 } 1721 if (skip) 1722 continue; 1723 /* 1724 * Not matched against any standard path, add the path 1725 * to result. Separate consequtive paths with ':'. 1726 */ 1727 if (fcount > 0) { 1728 filtered_path[fndx] = ':'; 1729 fndx++; 1730 } 1731 fcount++; 1732 flen = strlen(hintpath->dls_name); 1733 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1734 fndx += flen; 1735 } 1736 filtered_path[fndx] = '\0'; 1737 1738 free(SLPinfo); 1739 free(hintinfo); 1740 1741filt_ret: 1742 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1743} 1744 1745static void 1746init_dag(Obj_Entry *root) 1747{ 1748 const Needed_Entry *needed; 1749 const Objlist_Entry *elm; 1750 DoneList donelist; 1751 1752 if (root->dag_inited) 1753 return; 1754 donelist_init(&donelist); 1755 1756 /* Root object belongs to own DAG. */ 1757 objlist_push_tail(&root->dldags, root); 1758 objlist_push_tail(&root->dagmembers, root); 1759 donelist_check(&donelist, root); 1760 1761 /* 1762 * Add dependencies of root object to DAG in breadth order 1763 * by exploiting the fact that each new object get added 1764 * to the tail of the dagmembers list. 1765 */ 1766 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1767 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1768 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1769 continue; 1770 objlist_push_tail(&needed->obj->dldags, root); 1771 objlist_push_tail(&root->dagmembers, needed->obj); 1772 } 1773 } 1774 root->dag_inited = true; 1775} 1776 1777static void 1778process_nodelete(Obj_Entry *root) 1779{ 1780 const Objlist_Entry *elm; 1781 1782 /* 1783 * Walk over object DAG and process every dependent object that 1784 * is marked as DF_1_NODELETE. They need to grow their own DAG, 1785 * which then should have its reference upped separately. 1786 */ 1787 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1788 if (elm->obj != NULL && elm->obj->z_nodelete && 1789 !elm->obj->ref_nodel) { 1790 dbg("obj %s nodelete", elm->obj->path); 1791 init_dag(elm->obj); 1792 ref_dag(elm->obj); 1793 elm->obj->ref_nodel = true; 1794 } 1795 } 1796} 1797/* 1798 * Initialize the dynamic linker. The argument is the address at which 1799 * the dynamic linker has been mapped into memory. The primary task of 1800 * this function is to relocate the dynamic linker. 1801 */ 1802static void 1803init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 1804{ 1805 Obj_Entry objtmp; /* Temporary rtld object */ 1806 const Elf_Dyn *dyn_rpath; 1807 const Elf_Dyn *dyn_soname; 1808 const Elf_Dyn *dyn_runpath; 1809 1810 /* 1811 * Conjure up an Obj_Entry structure for the dynamic linker. 1812 * 1813 * The "path" member can't be initialized yet because string constants 1814 * cannot yet be accessed. Below we will set it correctly. 1815 */ 1816 memset(&objtmp, 0, sizeof(objtmp)); 1817 objtmp.path = NULL; 1818 objtmp.rtld = true; 1819 objtmp.mapbase = mapbase; 1820#ifdef PIC 1821 objtmp.relocbase = mapbase; 1822#endif 1823 if (RTLD_IS_DYNAMIC()) { 1824 objtmp.dynamic = rtld_dynamic(&objtmp); 1825 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 1826 assert(objtmp.needed == NULL); 1827#if !defined(__mips__) 1828 /* MIPS has a bogus DT_TEXTREL. */ 1829 assert(!objtmp.textrel); 1830#endif 1831 1832 /* 1833 * Temporarily put the dynamic linker entry into the object list, so 1834 * that symbols can be found. 1835 */ 1836 1837 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 1838 } 1839 1840 /* Initialize the object list. */ 1841 obj_tail = &obj_list; 1842 1843 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1844 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1845 1846 /* The page size is required by the dynamic memory allocator. */ 1847 init_pagesizes(aux_info); 1848 1849 if (aux_info[AT_OSRELDATE] != NULL) 1850 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 1851 1852 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 1853 1854 /* Replace the path with a dynamically allocated copy. */ 1855 obj_rtld.path = xstrdup(PATH_RTLD); 1856 1857 r_debug.r_brk = r_debug_state; 1858 r_debug.r_state = RT_CONSISTENT; 1859} 1860 1861/* 1862 * Retrieve the array of supported page sizes. The kernel provides the page 1863 * sizes in increasing order. 1864 */ 1865static void 1866init_pagesizes(Elf_Auxinfo **aux_info) 1867{ 1868 static size_t psa[MAXPAGESIZES]; 1869 int mib[2]; 1870 size_t len, size; 1871 1872 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 1873 NULL) { 1874 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 1875 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 1876 } else { 1877 len = 2; 1878 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 1879 size = sizeof(psa); 1880 else { 1881 /* As a fallback, retrieve the base page size. */ 1882 size = sizeof(psa[0]); 1883 if (aux_info[AT_PAGESZ] != NULL) { 1884 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 1885 goto psa_filled; 1886 } else { 1887 mib[0] = CTL_HW; 1888 mib[1] = HW_PAGESIZE; 1889 len = 2; 1890 } 1891 } 1892 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 1893 _rtld_error("sysctl for hw.pagesize(s) failed"); 1894 die(); 1895 } 1896psa_filled: 1897 pagesizes = psa; 1898 } 1899 npagesizes = size / sizeof(pagesizes[0]); 1900 /* Discard any invalid entries at the end of the array. */ 1901 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 1902 npagesizes--; 1903} 1904 1905/* 1906 * Add the init functions from a needed object list (and its recursive 1907 * needed objects) to "list". This is not used directly; it is a helper 1908 * function for initlist_add_objects(). The write lock must be held 1909 * when this function is called. 1910 */ 1911static void 1912initlist_add_neededs(Needed_Entry *needed, Objlist *list) 1913{ 1914 /* Recursively process the successor needed objects. */ 1915 if (needed->next != NULL) 1916 initlist_add_neededs(needed->next, list); 1917 1918 /* Process the current needed object. */ 1919 if (needed->obj != NULL) 1920 initlist_add_objects(needed->obj, &needed->obj->next, list); 1921} 1922 1923/* 1924 * Scan all of the DAGs rooted in the range of objects from "obj" to 1925 * "tail" and add their init functions to "list". This recurses over 1926 * the DAGs and ensure the proper init ordering such that each object's 1927 * needed libraries are initialized before the object itself. At the 1928 * same time, this function adds the objects to the global finalization 1929 * list "list_fini" in the opposite order. The write lock must be 1930 * held when this function is called. 1931 */ 1932static void 1933initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list) 1934{ 1935 1936 if (obj->init_scanned || obj->init_done) 1937 return; 1938 obj->init_scanned = true; 1939 1940 /* Recursively process the successor objects. */ 1941 if (&obj->next != tail) 1942 initlist_add_objects(obj->next, tail, list); 1943 1944 /* Recursively process the needed objects. */ 1945 if (obj->needed != NULL) 1946 initlist_add_neededs(obj->needed, list); 1947 if (obj->needed_filtees != NULL) 1948 initlist_add_neededs(obj->needed_filtees, list); 1949 if (obj->needed_aux_filtees != NULL) 1950 initlist_add_neededs(obj->needed_aux_filtees, list); 1951 1952 /* Add the object to the init list. */ 1953 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL || 1954 obj->init_array != (Elf_Addr)NULL) 1955 objlist_push_tail(list, obj); 1956 1957 /* Add the object to the global fini list in the reverse order. */ 1958 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 1959 && !obj->on_fini_list) { 1960 objlist_push_head(&list_fini, obj); 1961 obj->on_fini_list = true; 1962 } 1963} 1964 1965#ifndef FPTR_TARGET 1966#define FPTR_TARGET(f) ((Elf_Addr) (f)) 1967#endif 1968 1969static void 1970free_needed_filtees(Needed_Entry *n) 1971{ 1972 Needed_Entry *needed, *needed1; 1973 1974 for (needed = n; needed != NULL; needed = needed->next) { 1975 if (needed->obj != NULL) { 1976 dlclose(needed->obj); 1977 needed->obj = NULL; 1978 } 1979 } 1980 for (needed = n; needed != NULL; needed = needed1) { 1981 needed1 = needed->next; 1982 free(needed); 1983 } 1984} 1985 1986static void 1987unload_filtees(Obj_Entry *obj) 1988{ 1989 1990 free_needed_filtees(obj->needed_filtees); 1991 obj->needed_filtees = NULL; 1992 free_needed_filtees(obj->needed_aux_filtees); 1993 obj->needed_aux_filtees = NULL; 1994 obj->filtees_loaded = false; 1995} 1996 1997static void 1998load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 1999 RtldLockState *lockstate) 2000{ 2001 2002 for (; needed != NULL; needed = needed->next) { 2003 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2004 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2005 RTLD_LOCAL, lockstate); 2006 } 2007} 2008 2009static void 2010load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2011{ 2012 2013 lock_restart_for_upgrade(lockstate); 2014 if (!obj->filtees_loaded) { 2015 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2016 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2017 obj->filtees_loaded = true; 2018 } 2019} 2020 2021static int 2022process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2023{ 2024 Obj_Entry *obj1; 2025 2026 for (; needed != NULL; needed = needed->next) { 2027 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2028 flags & ~RTLD_LO_NOLOAD); 2029 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2030 return (-1); 2031 } 2032 return (0); 2033} 2034 2035/* 2036 * Given a shared object, traverse its list of needed objects, and load 2037 * each of them. Returns 0 on success. Generates an error message and 2038 * returns -1 on failure. 2039 */ 2040static int 2041load_needed_objects(Obj_Entry *first, int flags) 2042{ 2043 Obj_Entry *obj; 2044 2045 for (obj = first; obj != NULL; obj = obj->next) { 2046 if (process_needed(obj, obj->needed, flags) == -1) 2047 return (-1); 2048 } 2049 return (0); 2050} 2051 2052static int 2053load_preload_objects(void) 2054{ 2055 char *p = ld_preload; 2056 Obj_Entry *obj; 2057 static const char delim[] = " \t:;"; 2058 2059 if (p == NULL) 2060 return 0; 2061 2062 p += strspn(p, delim); 2063 while (*p != '\0') { 2064 size_t len = strcspn(p, delim); 2065 char savech; 2066 2067 savech = p[len]; 2068 p[len] = '\0'; 2069 obj = load_object(p, -1, NULL, 0); 2070 if (obj == NULL) 2071 return -1; /* XXX - cleanup */ 2072 obj->z_interpose = true; 2073 p[len] = savech; 2074 p += len; 2075 p += strspn(p, delim); 2076 } 2077 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2078 return 0; 2079} 2080 2081static const char * 2082printable_path(const char *path) 2083{ 2084 2085 return (path == NULL ? "<unknown>" : path); 2086} 2087 2088/* 2089 * Load a shared object into memory, if it is not already loaded. The 2090 * object may be specified by name or by user-supplied file descriptor 2091 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2092 * duplicate is. 2093 * 2094 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2095 * on failure. 2096 */ 2097static Obj_Entry * 2098load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2099{ 2100 Obj_Entry *obj; 2101 int fd; 2102 struct stat sb; 2103 char *path; 2104 2105 if (name != NULL) { 2106 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 2107 if (object_match_name(obj, name)) 2108 return (obj); 2109 } 2110 2111 path = find_library(name, refobj); 2112 if (path == NULL) 2113 return (NULL); 2114 } else 2115 path = NULL; 2116 2117 /* 2118 * If we didn't find a match by pathname, or the name is not 2119 * supplied, open the file and check again by device and inode. 2120 * This avoids false mismatches caused by multiple links or ".." 2121 * in pathnames. 2122 * 2123 * To avoid a race, we open the file and use fstat() rather than 2124 * using stat(). 2125 */ 2126 fd = -1; 2127 if (fd_u == -1) { 2128 if ((fd = open(path, O_RDONLY | O_CLOEXEC)) == -1) { 2129 _rtld_error("Cannot open \"%s\"", path); 2130 free(path); 2131 return (NULL); 2132 } 2133 } else { 2134 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2135 if (fd == -1) { 2136 _rtld_error("Cannot dup fd"); 2137 free(path); 2138 return (NULL); 2139 } 2140 } 2141 if (fstat(fd, &sb) == -1) { 2142 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2143 close(fd); 2144 free(path); 2145 return NULL; 2146 } 2147 for (obj = obj_list->next; obj != NULL; obj = obj->next) 2148 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2149 break; 2150 if (obj != NULL && name != NULL) { 2151 object_add_name(obj, name); 2152 free(path); 2153 close(fd); 2154 return obj; 2155 } 2156 if (flags & RTLD_LO_NOLOAD) { 2157 free(path); 2158 close(fd); 2159 return (NULL); 2160 } 2161 2162 /* First use of this object, so we must map it in */ 2163 obj = do_load_object(fd, name, path, &sb, flags); 2164 if (obj == NULL) 2165 free(path); 2166 close(fd); 2167 2168 return obj; 2169} 2170 2171static Obj_Entry * 2172do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2173 int flags) 2174{ 2175 Obj_Entry *obj; 2176 struct statfs fs; 2177 2178 /* 2179 * but first, make sure that environment variables haven't been 2180 * used to circumvent the noexec flag on a filesystem. 2181 */ 2182 if (dangerous_ld_env) { 2183 if (fstatfs(fd, &fs) != 0) { 2184 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2185 return NULL; 2186 } 2187 if (fs.f_flags & MNT_NOEXEC) { 2188 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 2189 return NULL; 2190 } 2191 } 2192 dbg("loading \"%s\"", printable_path(path)); 2193 obj = map_object(fd, printable_path(path), sbp); 2194 if (obj == NULL) 2195 return NULL; 2196 2197 /* 2198 * If DT_SONAME is present in the object, digest_dynamic2 already 2199 * added it to the object names. 2200 */ 2201 if (name != NULL) 2202 object_add_name(obj, name); 2203 obj->path = path; 2204 digest_dynamic(obj, 0); 2205 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2206 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2207 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2208 RTLD_LO_DLOPEN) { 2209 dbg("refusing to load non-loadable \"%s\"", obj->path); 2210 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2211 munmap(obj->mapbase, obj->mapsize); 2212 obj_free(obj); 2213 return (NULL); 2214 } 2215 2216 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2217 *obj_tail = obj; 2218 obj_tail = &obj->next; 2219 obj_count++; 2220 obj_loads++; 2221 linkmap_add(obj); /* for GDB & dlinfo() */ 2222 max_stack_flags |= obj->stack_flags; 2223 2224 dbg(" %p .. %p: %s", obj->mapbase, 2225 obj->mapbase + obj->mapsize - 1, obj->path); 2226 if (obj->textrel) 2227 dbg(" WARNING: %s has impure text", obj->path); 2228 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2229 obj->path); 2230 2231 return obj; 2232} 2233 2234static Obj_Entry * 2235obj_from_addr(const void *addr) 2236{ 2237 Obj_Entry *obj; 2238 2239 for (obj = obj_list; obj != NULL; obj = obj->next) { 2240 if (addr < (void *) obj->mapbase) 2241 continue; 2242 if (addr < (void *) (obj->mapbase + obj->mapsize)) 2243 return obj; 2244 } 2245 return NULL; 2246} 2247 2248static void 2249preinit_main(void) 2250{ 2251 Elf_Addr *preinit_addr; 2252 int index; 2253 2254 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2255 if (preinit_addr == NULL) 2256 return; 2257 2258 for (index = 0; index < obj_main->preinit_array_num; index++) { 2259 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2260 dbg("calling preinit function for %s at %p", obj_main->path, 2261 (void *)preinit_addr[index]); 2262 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2263 0, 0, obj_main->path); 2264 call_init_pointer(obj_main, preinit_addr[index]); 2265 } 2266 } 2267} 2268 2269/* 2270 * Call the finalization functions for each of the objects in "list" 2271 * belonging to the DAG of "root" and referenced once. If NULL "root" 2272 * is specified, every finalization function will be called regardless 2273 * of the reference count and the list elements won't be freed. All of 2274 * the objects are expected to have non-NULL fini functions. 2275 */ 2276static void 2277objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2278{ 2279 Objlist_Entry *elm; 2280 char *saved_msg; 2281 Elf_Addr *fini_addr; 2282 int index; 2283 2284 assert(root == NULL || root->refcount == 1); 2285 2286 /* 2287 * Preserve the current error message since a fini function might 2288 * call into the dynamic linker and overwrite it. 2289 */ 2290 saved_msg = errmsg_save(); 2291 do { 2292 STAILQ_FOREACH(elm, list, link) { 2293 if (root != NULL && (elm->obj->refcount != 1 || 2294 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2295 continue; 2296 /* Remove object from fini list to prevent recursive invocation. */ 2297 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2298 /* 2299 * XXX: If a dlopen() call references an object while the 2300 * fini function is in progress, we might end up trying to 2301 * unload the referenced object in dlclose() or the object 2302 * won't be unloaded although its fini function has been 2303 * called. 2304 */ 2305 lock_release(rtld_bind_lock, lockstate); 2306 2307 /* 2308 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2309 * When this happens, DT_FINI_ARRAY is processed first. 2310 */ 2311 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2312 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2313 for (index = elm->obj->fini_array_num - 1; index >= 0; 2314 index--) { 2315 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2316 dbg("calling fini function for %s at %p", 2317 elm->obj->path, (void *)fini_addr[index]); 2318 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2319 (void *)fini_addr[index], 0, 0, elm->obj->path); 2320 call_initfini_pointer(elm->obj, fini_addr[index]); 2321 } 2322 } 2323 } 2324 if (elm->obj->fini != (Elf_Addr)NULL) { 2325 dbg("calling fini function for %s at %p", elm->obj->path, 2326 (void *)elm->obj->fini); 2327 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2328 0, 0, elm->obj->path); 2329 call_initfini_pointer(elm->obj, elm->obj->fini); 2330 } 2331 wlock_acquire(rtld_bind_lock, lockstate); 2332 /* No need to free anything if process is going down. */ 2333 if (root != NULL) 2334 free(elm); 2335 /* 2336 * We must restart the list traversal after every fini call 2337 * because a dlclose() call from the fini function or from 2338 * another thread might have modified the reference counts. 2339 */ 2340 break; 2341 } 2342 } while (elm != NULL); 2343 errmsg_restore(saved_msg); 2344} 2345 2346/* 2347 * Call the initialization functions for each of the objects in 2348 * "list". All of the objects are expected to have non-NULL init 2349 * functions. 2350 */ 2351static void 2352objlist_call_init(Objlist *list, RtldLockState *lockstate) 2353{ 2354 Objlist_Entry *elm; 2355 Obj_Entry *obj; 2356 char *saved_msg; 2357 Elf_Addr *init_addr; 2358 int index; 2359 2360 /* 2361 * Clean init_scanned flag so that objects can be rechecked and 2362 * possibly initialized earlier if any of vectors called below 2363 * cause the change by using dlopen. 2364 */ 2365 for (obj = obj_list; obj != NULL; obj = obj->next) 2366 obj->init_scanned = false; 2367 2368 /* 2369 * Preserve the current error message since an init function might 2370 * call into the dynamic linker and overwrite it. 2371 */ 2372 saved_msg = errmsg_save(); 2373 STAILQ_FOREACH(elm, list, link) { 2374 if (elm->obj->init_done) /* Initialized early. */ 2375 continue; 2376 /* 2377 * Race: other thread might try to use this object before current 2378 * one completes the initilization. Not much can be done here 2379 * without better locking. 2380 */ 2381 elm->obj->init_done = true; 2382 lock_release(rtld_bind_lock, lockstate); 2383 2384 /* 2385 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2386 * When this happens, DT_INIT is processed first. 2387 */ 2388 if (elm->obj->init != (Elf_Addr)NULL) { 2389 dbg("calling init function for %s at %p", elm->obj->path, 2390 (void *)elm->obj->init); 2391 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2392 0, 0, elm->obj->path); 2393 call_initfini_pointer(elm->obj, elm->obj->init); 2394 } 2395 init_addr = (Elf_Addr *)elm->obj->init_array; 2396 if (init_addr != NULL) { 2397 for (index = 0; index < elm->obj->init_array_num; index++) { 2398 if (init_addr[index] != 0 && init_addr[index] != 1) { 2399 dbg("calling init function for %s at %p", elm->obj->path, 2400 (void *)init_addr[index]); 2401 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2402 (void *)init_addr[index], 0, 0, elm->obj->path); 2403 call_init_pointer(elm->obj, init_addr[index]); 2404 } 2405 } 2406 } 2407 wlock_acquire(rtld_bind_lock, lockstate); 2408 } 2409 errmsg_restore(saved_msg); 2410} 2411 2412static void 2413objlist_clear(Objlist *list) 2414{ 2415 Objlist_Entry *elm; 2416 2417 while (!STAILQ_EMPTY(list)) { 2418 elm = STAILQ_FIRST(list); 2419 STAILQ_REMOVE_HEAD(list, link); 2420 free(elm); 2421 } 2422} 2423 2424static Objlist_Entry * 2425objlist_find(Objlist *list, const Obj_Entry *obj) 2426{ 2427 Objlist_Entry *elm; 2428 2429 STAILQ_FOREACH(elm, list, link) 2430 if (elm->obj == obj) 2431 return elm; 2432 return NULL; 2433} 2434 2435static void 2436objlist_init(Objlist *list) 2437{ 2438 STAILQ_INIT(list); 2439} 2440 2441static void 2442objlist_push_head(Objlist *list, Obj_Entry *obj) 2443{ 2444 Objlist_Entry *elm; 2445 2446 elm = NEW(Objlist_Entry); 2447 elm->obj = obj; 2448 STAILQ_INSERT_HEAD(list, elm, link); 2449} 2450 2451static void 2452objlist_push_tail(Objlist *list, Obj_Entry *obj) 2453{ 2454 Objlist_Entry *elm; 2455 2456 elm = NEW(Objlist_Entry); 2457 elm->obj = obj; 2458 STAILQ_INSERT_TAIL(list, elm, link); 2459} 2460 2461static void 2462objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2463{ 2464 Objlist_Entry *elm, *listelm; 2465 2466 STAILQ_FOREACH(listelm, list, link) { 2467 if (listelm->obj == listobj) 2468 break; 2469 } 2470 elm = NEW(Objlist_Entry); 2471 elm->obj = obj; 2472 if (listelm != NULL) 2473 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2474 else 2475 STAILQ_INSERT_TAIL(list, elm, link); 2476} 2477 2478static void 2479objlist_remove(Objlist *list, Obj_Entry *obj) 2480{ 2481 Objlist_Entry *elm; 2482 2483 if ((elm = objlist_find(list, obj)) != NULL) { 2484 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2485 free(elm); 2486 } 2487} 2488 2489/* 2490 * Relocate dag rooted in the specified object. 2491 * Returns 0 on success, or -1 on failure. 2492 */ 2493 2494static int 2495relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2496 int flags, RtldLockState *lockstate) 2497{ 2498 Objlist_Entry *elm; 2499 int error; 2500 2501 error = 0; 2502 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2503 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2504 lockstate); 2505 if (error == -1) 2506 break; 2507 } 2508 return (error); 2509} 2510 2511/* 2512 * Relocate single object. 2513 * Returns 0 on success, or -1 on failure. 2514 */ 2515static int 2516relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2517 int flags, RtldLockState *lockstate) 2518{ 2519 2520 if (obj->relocated) 2521 return (0); 2522 obj->relocated = true; 2523 if (obj != rtldobj) 2524 dbg("relocating \"%s\"", obj->path); 2525 2526 if (obj->symtab == NULL || obj->strtab == NULL || 2527 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2528 _rtld_error("%s: Shared object has no run-time symbol table", 2529 obj->path); 2530 return (-1); 2531 } 2532 2533 if (obj->textrel) { 2534 /* There are relocations to the write-protected text segment. */ 2535 if (mprotect(obj->mapbase, obj->textsize, 2536 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) { 2537 _rtld_error("%s: Cannot write-enable text segment: %s", 2538 obj->path, rtld_strerror(errno)); 2539 return (-1); 2540 } 2541 } 2542 2543 /* Process the non-PLT non-IFUNC relocations. */ 2544 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2545 return (-1); 2546 2547 if (obj->textrel) { /* Re-protected the text segment. */ 2548 if (mprotect(obj->mapbase, obj->textsize, 2549 PROT_READ|PROT_EXEC) == -1) { 2550 _rtld_error("%s: Cannot write-protect text segment: %s", 2551 obj->path, rtld_strerror(errno)); 2552 return (-1); 2553 } 2554 } 2555 2556 /* Set the special PLT or GOT entries. */ 2557 init_pltgot(obj); 2558 2559 /* Process the PLT relocations. */ 2560 if (reloc_plt(obj) == -1) 2561 return (-1); 2562 /* Relocate the jump slots if we are doing immediate binding. */ 2563 if (obj->bind_now || bind_now) 2564 if (reloc_jmpslots(obj, flags, lockstate) == -1) 2565 return (-1); 2566 2567 /* 2568 * Process the non-PLT IFUNC relocations. The relocations are 2569 * processed in two phases, because IFUNC resolvers may 2570 * reference other symbols, which must be readily processed 2571 * before resolvers are called. 2572 */ 2573 if (obj->non_plt_gnu_ifunc && 2574 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate)) 2575 return (-1); 2576 2577 if (obj->relro_size > 0) { 2578 if (mprotect(obj->relro_page, obj->relro_size, 2579 PROT_READ) == -1) { 2580 _rtld_error("%s: Cannot enforce relro protection: %s", 2581 obj->path, rtld_strerror(errno)); 2582 return (-1); 2583 } 2584 } 2585 2586 /* 2587 * Set up the magic number and version in the Obj_Entry. These 2588 * were checked in the crt1.o from the original ElfKit, so we 2589 * set them for backward compatibility. 2590 */ 2591 obj->magic = RTLD_MAGIC; 2592 obj->version = RTLD_VERSION; 2593 2594 return (0); 2595} 2596 2597/* 2598 * Relocate newly-loaded shared objects. The argument is a pointer to 2599 * the Obj_Entry for the first such object. All objects from the first 2600 * to the end of the list of objects are relocated. Returns 0 on success, 2601 * or -1 on failure. 2602 */ 2603static int 2604relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2605 int flags, RtldLockState *lockstate) 2606{ 2607 Obj_Entry *obj; 2608 int error; 2609 2610 for (error = 0, obj = first; obj != NULL; obj = obj->next) { 2611 error = relocate_object(obj, bind_now, rtldobj, flags, 2612 lockstate); 2613 if (error == -1) 2614 break; 2615 } 2616 return (error); 2617} 2618 2619/* 2620 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2621 * referencing STT_GNU_IFUNC symbols is postponed till the other 2622 * relocations are done. The indirect functions specified as 2623 * ifunc are allowed to call other symbols, so we need to have 2624 * objects relocated before asking for resolution from indirects. 2625 * 2626 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2627 * instead of the usual lazy handling of PLT slots. It is 2628 * consistent with how GNU does it. 2629 */ 2630static int 2631resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2632 RtldLockState *lockstate) 2633{ 2634 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2635 return (-1); 2636 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2637 reloc_gnu_ifunc(obj, flags, lockstate) == -1) 2638 return (-1); 2639 return (0); 2640} 2641 2642static int 2643resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags, 2644 RtldLockState *lockstate) 2645{ 2646 Obj_Entry *obj; 2647 2648 for (obj = first; obj != NULL; obj = obj->next) { 2649 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1) 2650 return (-1); 2651 } 2652 return (0); 2653} 2654 2655static int 2656initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2657 RtldLockState *lockstate) 2658{ 2659 Objlist_Entry *elm; 2660 2661 STAILQ_FOREACH(elm, list, link) { 2662 if (resolve_object_ifunc(elm->obj, bind_now, flags, 2663 lockstate) == -1) 2664 return (-1); 2665 } 2666 return (0); 2667} 2668 2669/* 2670 * Cleanup procedure. It will be called (by the atexit mechanism) just 2671 * before the process exits. 2672 */ 2673static void 2674rtld_exit(void) 2675{ 2676 RtldLockState lockstate; 2677 2678 wlock_acquire(rtld_bind_lock, &lockstate); 2679 dbg("rtld_exit()"); 2680 objlist_call_fini(&list_fini, NULL, &lockstate); 2681 /* No need to remove the items from the list, since we are exiting. */ 2682 if (!libmap_disable) 2683 lm_fini(); 2684 lock_release(rtld_bind_lock, &lockstate); 2685} 2686 2687/* 2688 * Iterate over a search path, translate each element, and invoke the 2689 * callback on the result. 2690 */ 2691static void * 2692path_enumerate(const char *path, path_enum_proc callback, void *arg) 2693{ 2694 const char *trans; 2695 if (path == NULL) 2696 return (NULL); 2697 2698 path += strspn(path, ":;"); 2699 while (*path != '\0') { 2700 size_t len; 2701 char *res; 2702 2703 len = strcspn(path, ":;"); 2704 trans = lm_findn(NULL, path, len); 2705 if (trans) 2706 res = callback(trans, strlen(trans), arg); 2707 else 2708 res = callback(path, len, arg); 2709 2710 if (res != NULL) 2711 return (res); 2712 2713 path += len; 2714 path += strspn(path, ":;"); 2715 } 2716 2717 return (NULL); 2718} 2719 2720struct try_library_args { 2721 const char *name; 2722 size_t namelen; 2723 char *buffer; 2724 size_t buflen; 2725}; 2726 2727static void * 2728try_library_path(const char *dir, size_t dirlen, void *param) 2729{ 2730 struct try_library_args *arg; 2731 2732 arg = param; 2733 if (*dir == '/' || trust) { 2734 char *pathname; 2735 2736 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 2737 return (NULL); 2738 2739 pathname = arg->buffer; 2740 strncpy(pathname, dir, dirlen); 2741 pathname[dirlen] = '/'; 2742 strcpy(pathname + dirlen + 1, arg->name); 2743 2744 dbg(" Trying \"%s\"", pathname); 2745 if (access(pathname, F_OK) == 0) { /* We found it */ 2746 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 2747 strcpy(pathname, arg->buffer); 2748 return (pathname); 2749 } 2750 } 2751 return (NULL); 2752} 2753 2754static char * 2755search_library_path(const char *name, const char *path) 2756{ 2757 char *p; 2758 struct try_library_args arg; 2759 2760 if (path == NULL) 2761 return NULL; 2762 2763 arg.name = name; 2764 arg.namelen = strlen(name); 2765 arg.buffer = xmalloc(PATH_MAX); 2766 arg.buflen = PATH_MAX; 2767 2768 p = path_enumerate(path, try_library_path, &arg); 2769 2770 free(arg.buffer); 2771 2772 return (p); 2773} 2774 2775int 2776dlclose(void *handle) 2777{ 2778 Obj_Entry *root; 2779 RtldLockState lockstate; 2780 2781 wlock_acquire(rtld_bind_lock, &lockstate); 2782 root = dlcheck(handle); 2783 if (root == NULL) { 2784 lock_release(rtld_bind_lock, &lockstate); 2785 return -1; 2786 } 2787 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 2788 root->path); 2789 2790 /* Unreference the object and its dependencies. */ 2791 root->dl_refcount--; 2792 2793 if (root->refcount == 1) { 2794 /* 2795 * The object will be no longer referenced, so we must unload it. 2796 * First, call the fini functions. 2797 */ 2798 objlist_call_fini(&list_fini, root, &lockstate); 2799 2800 unref_dag(root); 2801 2802 /* Finish cleaning up the newly-unreferenced objects. */ 2803 GDB_STATE(RT_DELETE,&root->linkmap); 2804 unload_object(root); 2805 GDB_STATE(RT_CONSISTENT,NULL); 2806 } else 2807 unref_dag(root); 2808 2809 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 2810 lock_release(rtld_bind_lock, &lockstate); 2811 return 0; 2812} 2813 2814char * 2815dlerror(void) 2816{ 2817 char *msg = error_message; 2818 error_message = NULL; 2819 return msg; 2820} 2821 2822/* 2823 * This function is deprecated and has no effect. 2824 */ 2825void 2826dllockinit(void *context, 2827 void *(*lock_create)(void *context), 2828 void (*rlock_acquire)(void *lock), 2829 void (*wlock_acquire)(void *lock), 2830 void (*lock_release)(void *lock), 2831 void (*lock_destroy)(void *lock), 2832 void (*context_destroy)(void *context)) 2833{ 2834 static void *cur_context; 2835 static void (*cur_context_destroy)(void *); 2836 2837 /* Just destroy the context from the previous call, if necessary. */ 2838 if (cur_context_destroy != NULL) 2839 cur_context_destroy(cur_context); 2840 cur_context = context; 2841 cur_context_destroy = context_destroy; 2842} 2843 2844void * 2845dlopen(const char *name, int mode) 2846{ 2847 2848 return (rtld_dlopen(name, -1, mode)); 2849} 2850 2851void * 2852fdlopen(int fd, int mode) 2853{ 2854 2855 return (rtld_dlopen(NULL, fd, mode)); 2856} 2857 2858static void * 2859rtld_dlopen(const char *name, int fd, int mode) 2860{ 2861 RtldLockState lockstate; 2862 int lo_flags; 2863 2864 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 2865 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 2866 if (ld_tracing != NULL) { 2867 rlock_acquire(rtld_bind_lock, &lockstate); 2868 if (sigsetjmp(lockstate.env, 0) != 0) 2869 lock_upgrade(rtld_bind_lock, &lockstate); 2870 environ = (char **)*get_program_var_addr("environ", &lockstate); 2871 lock_release(rtld_bind_lock, &lockstate); 2872 } 2873 lo_flags = RTLD_LO_DLOPEN; 2874 if (mode & RTLD_NODELETE) 2875 lo_flags |= RTLD_LO_NODELETE; 2876 if (mode & RTLD_NOLOAD) 2877 lo_flags |= RTLD_LO_NOLOAD; 2878 if (ld_tracing != NULL) 2879 lo_flags |= RTLD_LO_TRACE; 2880 2881 return (dlopen_object(name, fd, obj_main, lo_flags, 2882 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 2883} 2884 2885static void 2886dlopen_cleanup(Obj_Entry *obj) 2887{ 2888 2889 obj->dl_refcount--; 2890 unref_dag(obj); 2891 if (obj->refcount == 0) 2892 unload_object(obj); 2893} 2894 2895static Obj_Entry * 2896dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 2897 int mode, RtldLockState *lockstate) 2898{ 2899 Obj_Entry **old_obj_tail; 2900 Obj_Entry *obj; 2901 Objlist initlist; 2902 RtldLockState mlockstate; 2903 int result; 2904 2905 objlist_init(&initlist); 2906 2907 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 2908 wlock_acquire(rtld_bind_lock, &mlockstate); 2909 lockstate = &mlockstate; 2910 } 2911 GDB_STATE(RT_ADD,NULL); 2912 2913 old_obj_tail = obj_tail; 2914 obj = NULL; 2915 if (name == NULL && fd == -1) { 2916 obj = obj_main; 2917 obj->refcount++; 2918 } else { 2919 obj = load_object(name, fd, refobj, lo_flags); 2920 } 2921 2922 if (obj) { 2923 obj->dl_refcount++; 2924 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 2925 objlist_push_tail(&list_global, obj); 2926 if (*old_obj_tail != NULL) { /* We loaded something new. */ 2927 assert(*old_obj_tail == obj); 2928 result = load_needed_objects(obj, 2929 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 2930 init_dag(obj); 2931 ref_dag(obj); 2932 if (result != -1) 2933 result = rtld_verify_versions(&obj->dagmembers); 2934 if (result != -1 && ld_tracing) 2935 goto trace; 2936 if (result == -1 || relocate_object_dag(obj, 2937 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 2938 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 2939 lockstate) == -1) { 2940 dlopen_cleanup(obj); 2941 obj = NULL; 2942 } else if (lo_flags & RTLD_LO_EARLY) { 2943 /* 2944 * Do not call the init functions for early loaded 2945 * filtees. The image is still not initialized enough 2946 * for them to work. 2947 * 2948 * Our object is found by the global object list and 2949 * will be ordered among all init calls done right 2950 * before transferring control to main. 2951 */ 2952 } else { 2953 /* Make list of init functions to call. */ 2954 initlist_add_objects(obj, &obj->next, &initlist); 2955 } 2956 /* 2957 * Process all no_delete objects here, given them own 2958 * DAGs to prevent their dependencies from being unloaded. 2959 * This has to be done after we have loaded all of the 2960 * dependencies, so that we do not miss any. 2961 */ 2962 if (obj != NULL) 2963 process_nodelete(obj); 2964 } else { 2965 /* 2966 * Bump the reference counts for objects on this DAG. If 2967 * this is the first dlopen() call for the object that was 2968 * already loaded as a dependency, initialize the dag 2969 * starting at it. 2970 */ 2971 init_dag(obj); 2972 ref_dag(obj); 2973 2974 if ((lo_flags & RTLD_LO_TRACE) != 0) 2975 goto trace; 2976 } 2977 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 2978 obj->z_nodelete) && !obj->ref_nodel) { 2979 dbg("obj %s nodelete", obj->path); 2980 ref_dag(obj); 2981 obj->z_nodelete = obj->ref_nodel = true; 2982 } 2983 } 2984 2985 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 2986 name); 2987 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 2988 2989 if (!(lo_flags & RTLD_LO_EARLY)) { 2990 map_stacks_exec(lockstate); 2991 } 2992 2993 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 2994 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 2995 lockstate) == -1) { 2996 objlist_clear(&initlist); 2997 dlopen_cleanup(obj); 2998 if (lockstate == &mlockstate) 2999 lock_release(rtld_bind_lock, lockstate); 3000 return (NULL); 3001 } 3002 3003 if (!(lo_flags & RTLD_LO_EARLY)) { 3004 /* Call the init functions. */ 3005 objlist_call_init(&initlist, lockstate); 3006 } 3007 objlist_clear(&initlist); 3008 if (lockstate == &mlockstate) 3009 lock_release(rtld_bind_lock, lockstate); 3010 return obj; 3011trace: 3012 trace_loaded_objects(obj); 3013 if (lockstate == &mlockstate) 3014 lock_release(rtld_bind_lock, lockstate); 3015 exit(0); 3016} 3017 3018static void * 3019do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3020 int flags) 3021{ 3022 DoneList donelist; 3023 const Obj_Entry *obj, *defobj; 3024 const Elf_Sym *def; 3025 SymLook req; 3026 RtldLockState lockstate; 3027#ifndef __ia64__ 3028 tls_index ti; 3029#endif 3030 int res; 3031 3032 def = NULL; 3033 defobj = NULL; 3034 symlook_init(&req, name); 3035 req.ventry = ve; 3036 req.flags = flags | SYMLOOK_IN_PLT; 3037 req.lockstate = &lockstate; 3038 3039 rlock_acquire(rtld_bind_lock, &lockstate); 3040 if (sigsetjmp(lockstate.env, 0) != 0) 3041 lock_upgrade(rtld_bind_lock, &lockstate); 3042 if (handle == NULL || handle == RTLD_NEXT || 3043 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3044 3045 if ((obj = obj_from_addr(retaddr)) == NULL) { 3046 _rtld_error("Cannot determine caller's shared object"); 3047 lock_release(rtld_bind_lock, &lockstate); 3048 return NULL; 3049 } 3050 if (handle == NULL) { /* Just the caller's shared object. */ 3051 res = symlook_obj(&req, obj); 3052 if (res == 0) { 3053 def = req.sym_out; 3054 defobj = req.defobj_out; 3055 } 3056 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3057 handle == RTLD_SELF) { /* ... caller included */ 3058 if (handle == RTLD_NEXT) 3059 obj = obj->next; 3060 for (; obj != NULL; obj = obj->next) { 3061 res = symlook_obj(&req, obj); 3062 if (res == 0) { 3063 if (def == NULL || 3064 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3065 def = req.sym_out; 3066 defobj = req.defobj_out; 3067 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3068 break; 3069 } 3070 } 3071 } 3072 /* 3073 * Search the dynamic linker itself, and possibly resolve the 3074 * symbol from there. This is how the application links to 3075 * dynamic linker services such as dlopen. 3076 */ 3077 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3078 res = symlook_obj(&req, &obj_rtld); 3079 if (res == 0) { 3080 def = req.sym_out; 3081 defobj = req.defobj_out; 3082 } 3083 } 3084 } else { 3085 assert(handle == RTLD_DEFAULT); 3086 res = symlook_default(&req, obj); 3087 if (res == 0) { 3088 defobj = req.defobj_out; 3089 def = req.sym_out; 3090 } 3091 } 3092 } else { 3093 if ((obj = dlcheck(handle)) == NULL) { 3094 lock_release(rtld_bind_lock, &lockstate); 3095 return NULL; 3096 } 3097 3098 donelist_init(&donelist); 3099 if (obj->mainprog) { 3100 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3101 res = symlook_global(&req, &donelist); 3102 if (res == 0) { 3103 def = req.sym_out; 3104 defobj = req.defobj_out; 3105 } 3106 /* 3107 * Search the dynamic linker itself, and possibly resolve the 3108 * symbol from there. This is how the application links to 3109 * dynamic linker services such as dlopen. 3110 */ 3111 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3112 res = symlook_obj(&req, &obj_rtld); 3113 if (res == 0) { 3114 def = req.sym_out; 3115 defobj = req.defobj_out; 3116 } 3117 } 3118 } 3119 else { 3120 /* Search the whole DAG rooted at the given object. */ 3121 res = symlook_list(&req, &obj->dagmembers, &donelist); 3122 if (res == 0) { 3123 def = req.sym_out; 3124 defobj = req.defobj_out; 3125 } 3126 } 3127 } 3128 3129 if (def != NULL) { 3130 lock_release(rtld_bind_lock, &lockstate); 3131 3132 /* 3133 * The value required by the caller is derived from the value 3134 * of the symbol. For the ia64 architecture, we need to 3135 * construct a function descriptor which the caller can use to 3136 * call the function with the right 'gp' value. For other 3137 * architectures and for non-functions, the value is simply 3138 * the relocated value of the symbol. 3139 */ 3140 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3141 return (make_function_pointer(def, defobj)); 3142 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3143 return (rtld_resolve_ifunc(defobj, def)); 3144 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3145#ifdef __ia64__ 3146 return (__tls_get_addr(defobj->tlsindex, def->st_value)); 3147#else 3148 ti.ti_module = defobj->tlsindex; 3149 ti.ti_offset = def->st_value; 3150 return (__tls_get_addr(&ti)); 3151#endif 3152 } else 3153 return (defobj->relocbase + def->st_value); 3154 } 3155 3156 _rtld_error("Undefined symbol \"%s\"", name); 3157 lock_release(rtld_bind_lock, &lockstate); 3158 return NULL; 3159} 3160 3161void * 3162dlsym(void *handle, const char *name) 3163{ 3164 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3165 SYMLOOK_DLSYM); 3166} 3167 3168dlfunc_t 3169dlfunc(void *handle, const char *name) 3170{ 3171 union { 3172 void *d; 3173 dlfunc_t f; 3174 } rv; 3175 3176 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3177 SYMLOOK_DLSYM); 3178 return (rv.f); 3179} 3180 3181void * 3182dlvsym(void *handle, const char *name, const char *version) 3183{ 3184 Ver_Entry ventry; 3185 3186 ventry.name = version; 3187 ventry.file = NULL; 3188 ventry.hash = elf_hash(version); 3189 ventry.flags= 0; 3190 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3191 SYMLOOK_DLSYM); 3192} 3193 3194int 3195_rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3196{ 3197 const Obj_Entry *obj; 3198 RtldLockState lockstate; 3199 3200 rlock_acquire(rtld_bind_lock, &lockstate); 3201 obj = obj_from_addr(addr); 3202 if (obj == NULL) { 3203 _rtld_error("No shared object contains address"); 3204 lock_release(rtld_bind_lock, &lockstate); 3205 return (0); 3206 } 3207 rtld_fill_dl_phdr_info(obj, phdr_info); 3208 lock_release(rtld_bind_lock, &lockstate); 3209 return (1); 3210} 3211 3212int 3213dladdr(const void *addr, Dl_info *info) 3214{ 3215 const Obj_Entry *obj; 3216 const Elf_Sym *def; 3217 void *symbol_addr; 3218 unsigned long symoffset; 3219 RtldLockState lockstate; 3220 3221 rlock_acquire(rtld_bind_lock, &lockstate); 3222 obj = obj_from_addr(addr); 3223 if (obj == NULL) { 3224 _rtld_error("No shared object contains address"); 3225 lock_release(rtld_bind_lock, &lockstate); 3226 return 0; 3227 } 3228 info->dli_fname = obj->path; 3229 info->dli_fbase = obj->mapbase; 3230 info->dli_saddr = (void *)0; 3231 info->dli_sname = NULL; 3232 3233 /* 3234 * Walk the symbol list looking for the symbol whose address is 3235 * closest to the address sent in. 3236 */ 3237 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3238 def = obj->symtab + symoffset; 3239 3240 /* 3241 * For skip the symbol if st_shndx is either SHN_UNDEF or 3242 * SHN_COMMON. 3243 */ 3244 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3245 continue; 3246 3247 /* 3248 * If the symbol is greater than the specified address, or if it 3249 * is further away from addr than the current nearest symbol, 3250 * then reject it. 3251 */ 3252 symbol_addr = obj->relocbase + def->st_value; 3253 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3254 continue; 3255 3256 /* Update our idea of the nearest symbol. */ 3257 info->dli_sname = obj->strtab + def->st_name; 3258 info->dli_saddr = symbol_addr; 3259 3260 /* Exact match? */ 3261 if (info->dli_saddr == addr) 3262 break; 3263 } 3264 lock_release(rtld_bind_lock, &lockstate); 3265 return 1; 3266} 3267 3268int 3269dlinfo(void *handle, int request, void *p) 3270{ 3271 const Obj_Entry *obj; 3272 RtldLockState lockstate; 3273 int error; 3274 3275 rlock_acquire(rtld_bind_lock, &lockstate); 3276 3277 if (handle == NULL || handle == RTLD_SELF) { 3278 void *retaddr; 3279 3280 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3281 if ((obj = obj_from_addr(retaddr)) == NULL) 3282 _rtld_error("Cannot determine caller's shared object"); 3283 } else 3284 obj = dlcheck(handle); 3285 3286 if (obj == NULL) { 3287 lock_release(rtld_bind_lock, &lockstate); 3288 return (-1); 3289 } 3290 3291 error = 0; 3292 switch (request) { 3293 case RTLD_DI_LINKMAP: 3294 *((struct link_map const **)p) = &obj->linkmap; 3295 break; 3296 case RTLD_DI_ORIGIN: 3297 error = rtld_dirname(obj->path, p); 3298 break; 3299 3300 case RTLD_DI_SERINFOSIZE: 3301 case RTLD_DI_SERINFO: 3302 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3303 break; 3304 3305 default: 3306 _rtld_error("Invalid request %d passed to dlinfo()", request); 3307 error = -1; 3308 } 3309 3310 lock_release(rtld_bind_lock, &lockstate); 3311 3312 return (error); 3313} 3314 3315static void 3316rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3317{ 3318 3319 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3320 phdr_info->dlpi_name = obj->path; 3321 phdr_info->dlpi_phdr = obj->phdr; 3322 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3323 phdr_info->dlpi_tls_modid = obj->tlsindex; 3324 phdr_info->dlpi_tls_data = obj->tlsinit; 3325 phdr_info->dlpi_adds = obj_loads; 3326 phdr_info->dlpi_subs = obj_loads - obj_count; 3327} 3328 3329int 3330dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3331{ 3332 struct dl_phdr_info phdr_info; 3333 const Obj_Entry *obj; 3334 RtldLockState bind_lockstate, phdr_lockstate; 3335 int error; 3336 3337 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3338 rlock_acquire(rtld_bind_lock, &bind_lockstate); 3339 3340 error = 0; 3341 3342 for (obj = obj_list; obj != NULL; obj = obj->next) { 3343 rtld_fill_dl_phdr_info(obj, &phdr_info); 3344 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0) 3345 break; 3346 3347 } 3348 lock_release(rtld_bind_lock, &bind_lockstate); 3349 lock_release(rtld_phdr_lock, &phdr_lockstate); 3350 3351 return (error); 3352} 3353 3354static void * 3355fill_search_info(const char *dir, size_t dirlen, void *param) 3356{ 3357 struct fill_search_info_args *arg; 3358 3359 arg = param; 3360 3361 if (arg->request == RTLD_DI_SERINFOSIZE) { 3362 arg->serinfo->dls_cnt ++; 3363 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3364 } else { 3365 struct dl_serpath *s_entry; 3366 3367 s_entry = arg->serpath; 3368 s_entry->dls_name = arg->strspace; 3369 s_entry->dls_flags = arg->flags; 3370 3371 strncpy(arg->strspace, dir, dirlen); 3372 arg->strspace[dirlen] = '\0'; 3373 3374 arg->strspace += dirlen + 1; 3375 arg->serpath++; 3376 } 3377 3378 return (NULL); 3379} 3380 3381static int 3382do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3383{ 3384 struct dl_serinfo _info; 3385 struct fill_search_info_args args; 3386 3387 args.request = RTLD_DI_SERINFOSIZE; 3388 args.serinfo = &_info; 3389 3390 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3391 _info.dls_cnt = 0; 3392 3393 path_enumerate(obj->rpath, fill_search_info, &args); 3394 path_enumerate(ld_library_path, fill_search_info, &args); 3395 path_enumerate(obj->runpath, fill_search_info, &args); 3396 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args); 3397 if (!obj->z_nodeflib) 3398 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 3399 3400 3401 if (request == RTLD_DI_SERINFOSIZE) { 3402 info->dls_size = _info.dls_size; 3403 info->dls_cnt = _info.dls_cnt; 3404 return (0); 3405 } 3406 3407 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3408 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3409 return (-1); 3410 } 3411 3412 args.request = RTLD_DI_SERINFO; 3413 args.serinfo = info; 3414 args.serpath = &info->dls_serpath[0]; 3415 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3416 3417 args.flags = LA_SER_RUNPATH; 3418 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 3419 return (-1); 3420 3421 args.flags = LA_SER_LIBPATH; 3422 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 3423 return (-1); 3424 3425 args.flags = LA_SER_RUNPATH; 3426 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL) 3427 return (-1); 3428 3429 args.flags = LA_SER_CONFIG; 3430 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args) 3431 != NULL) 3432 return (-1); 3433 3434 args.flags = LA_SER_DEFAULT; 3435 if (!obj->z_nodeflib && 3436 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 3437 return (-1); 3438 return (0); 3439} 3440 3441static int 3442rtld_dirname(const char *path, char *bname) 3443{ 3444 const char *endp; 3445 3446 /* Empty or NULL string gets treated as "." */ 3447 if (path == NULL || *path == '\0') { 3448 bname[0] = '.'; 3449 bname[1] = '\0'; 3450 return (0); 3451 } 3452 3453 /* Strip trailing slashes */ 3454 endp = path + strlen(path) - 1; 3455 while (endp > path && *endp == '/') 3456 endp--; 3457 3458 /* Find the start of the dir */ 3459 while (endp > path && *endp != '/') 3460 endp--; 3461 3462 /* Either the dir is "/" or there are no slashes */ 3463 if (endp == path) { 3464 bname[0] = *endp == '/' ? '/' : '.'; 3465 bname[1] = '\0'; 3466 return (0); 3467 } else { 3468 do { 3469 endp--; 3470 } while (endp > path && *endp == '/'); 3471 } 3472 3473 if (endp - path + 2 > PATH_MAX) 3474 { 3475 _rtld_error("Filename is too long: %s", path); 3476 return(-1); 3477 } 3478 3479 strncpy(bname, path, endp - path + 1); 3480 bname[endp - path + 1] = '\0'; 3481 return (0); 3482} 3483 3484static int 3485rtld_dirname_abs(const char *path, char *base) 3486{ 3487 char *last; 3488 3489 if (realpath(path, base) == NULL) 3490 return (-1); 3491 dbg("%s -> %s", path, base); 3492 last = strrchr(base, '/'); 3493 if (last == NULL) 3494 return (-1); 3495 if (last != base) 3496 *last = '\0'; 3497 return (0); 3498} 3499 3500static void 3501linkmap_add(Obj_Entry *obj) 3502{ 3503 struct link_map *l = &obj->linkmap; 3504 struct link_map *prev; 3505 3506 obj->linkmap.l_name = obj->path; 3507 obj->linkmap.l_addr = obj->mapbase; 3508 obj->linkmap.l_ld = obj->dynamic; 3509#ifdef __mips__ 3510 /* GDB needs load offset on MIPS to use the symbols */ 3511 obj->linkmap.l_offs = obj->relocbase; 3512#endif 3513 3514 if (r_debug.r_map == NULL) { 3515 r_debug.r_map = l; 3516 return; 3517 } 3518 3519 /* 3520 * Scan to the end of the list, but not past the entry for the 3521 * dynamic linker, which we want to keep at the very end. 3522 */ 3523 for (prev = r_debug.r_map; 3524 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3525 prev = prev->l_next) 3526 ; 3527 3528 /* Link in the new entry. */ 3529 l->l_prev = prev; 3530 l->l_next = prev->l_next; 3531 if (l->l_next != NULL) 3532 l->l_next->l_prev = l; 3533 prev->l_next = l; 3534} 3535 3536static void 3537linkmap_delete(Obj_Entry *obj) 3538{ 3539 struct link_map *l = &obj->linkmap; 3540 3541 if (l->l_prev == NULL) { 3542 if ((r_debug.r_map = l->l_next) != NULL) 3543 l->l_next->l_prev = NULL; 3544 return; 3545 } 3546 3547 if ((l->l_prev->l_next = l->l_next) != NULL) 3548 l->l_next->l_prev = l->l_prev; 3549} 3550 3551/* 3552 * Function for the debugger to set a breakpoint on to gain control. 3553 * 3554 * The two parameters allow the debugger to easily find and determine 3555 * what the runtime loader is doing and to whom it is doing it. 3556 * 3557 * When the loadhook trap is hit (r_debug_state, set at program 3558 * initialization), the arguments can be found on the stack: 3559 * 3560 * +8 struct link_map *m 3561 * +4 struct r_debug *rd 3562 * +0 RetAddr 3563 */ 3564void 3565r_debug_state(struct r_debug* rd, struct link_map *m) 3566{ 3567 /* 3568 * The following is a hack to force the compiler to emit calls to 3569 * this function, even when optimizing. If the function is empty, 3570 * the compiler is not obliged to emit any code for calls to it, 3571 * even when marked __noinline. However, gdb depends on those 3572 * calls being made. 3573 */ 3574 __compiler_membar(); 3575} 3576 3577/* 3578 * A function called after init routines have completed. This can be used to 3579 * break before a program's entry routine is called, and can be used when 3580 * main is not available in the symbol table. 3581 */ 3582void 3583_r_debug_postinit(struct link_map *m) 3584{ 3585 3586 /* See r_debug_state(). */ 3587 __compiler_membar(); 3588} 3589 3590/* 3591 * Get address of the pointer variable in the main program. 3592 * Prefer non-weak symbol over the weak one. 3593 */ 3594static const void ** 3595get_program_var_addr(const char *name, RtldLockState *lockstate) 3596{ 3597 SymLook req; 3598 DoneList donelist; 3599 3600 symlook_init(&req, name); 3601 req.lockstate = lockstate; 3602 donelist_init(&donelist); 3603 if (symlook_global(&req, &donelist) != 0) 3604 return (NULL); 3605 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 3606 return ((const void **)make_function_pointer(req.sym_out, 3607 req.defobj_out)); 3608 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 3609 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 3610 else 3611 return ((const void **)(req.defobj_out->relocbase + 3612 req.sym_out->st_value)); 3613} 3614 3615/* 3616 * Set a pointer variable in the main program to the given value. This 3617 * is used to set key variables such as "environ" before any of the 3618 * init functions are called. 3619 */ 3620static void 3621set_program_var(const char *name, const void *value) 3622{ 3623 const void **addr; 3624 3625 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 3626 dbg("\"%s\": *%p <-- %p", name, addr, value); 3627 *addr = value; 3628 } 3629} 3630 3631/* 3632 * Search the global objects, including dependencies and main object, 3633 * for the given symbol. 3634 */ 3635static int 3636symlook_global(SymLook *req, DoneList *donelist) 3637{ 3638 SymLook req1; 3639 const Objlist_Entry *elm; 3640 int res; 3641 3642 symlook_init_from_req(&req1, req); 3643 3644 /* Search all objects loaded at program start up. */ 3645 if (req->defobj_out == NULL || 3646 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3647 res = symlook_list(&req1, &list_main, donelist); 3648 if (res == 0 && (req->defobj_out == NULL || 3649 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3650 req->sym_out = req1.sym_out; 3651 req->defobj_out = req1.defobj_out; 3652 assert(req->defobj_out != NULL); 3653 } 3654 } 3655 3656 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 3657 STAILQ_FOREACH(elm, &list_global, link) { 3658 if (req->defobj_out != NULL && 3659 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3660 break; 3661 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 3662 if (res == 0 && (req->defobj_out == NULL || 3663 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3664 req->sym_out = req1.sym_out; 3665 req->defobj_out = req1.defobj_out; 3666 assert(req->defobj_out != NULL); 3667 } 3668 } 3669 3670 return (req->sym_out != NULL ? 0 : ESRCH); 3671} 3672 3673/* 3674 * Given a symbol name in a referencing object, find the corresponding 3675 * definition of the symbol. Returns a pointer to the symbol, or NULL if 3676 * no definition was found. Returns a pointer to the Obj_Entry of the 3677 * defining object via the reference parameter DEFOBJ_OUT. 3678 */ 3679static int 3680symlook_default(SymLook *req, const Obj_Entry *refobj) 3681{ 3682 DoneList donelist; 3683 const Objlist_Entry *elm; 3684 SymLook req1; 3685 int res; 3686 3687 donelist_init(&donelist); 3688 symlook_init_from_req(&req1, req); 3689 3690 /* Look first in the referencing object if linked symbolically. */ 3691 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 3692 res = symlook_obj(&req1, refobj); 3693 if (res == 0) { 3694 req->sym_out = req1.sym_out; 3695 req->defobj_out = req1.defobj_out; 3696 assert(req->defobj_out != NULL); 3697 } 3698 } 3699 3700 symlook_global(req, &donelist); 3701 3702 /* Search all dlopened DAGs containing the referencing object. */ 3703 STAILQ_FOREACH(elm, &refobj->dldags, link) { 3704 if (req->sym_out != NULL && 3705 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3706 break; 3707 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 3708 if (res == 0 && (req->sym_out == NULL || 3709 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3710 req->sym_out = req1.sym_out; 3711 req->defobj_out = req1.defobj_out; 3712 assert(req->defobj_out != NULL); 3713 } 3714 } 3715 3716 /* 3717 * Search the dynamic linker itself, and possibly resolve the 3718 * symbol from there. This is how the application links to 3719 * dynamic linker services such as dlopen. 3720 */ 3721 if (req->sym_out == NULL || 3722 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3723 res = symlook_obj(&req1, &obj_rtld); 3724 if (res == 0) { 3725 req->sym_out = req1.sym_out; 3726 req->defobj_out = req1.defobj_out; 3727 assert(req->defobj_out != NULL); 3728 } 3729 } 3730 3731 return (req->sym_out != NULL ? 0 : ESRCH); 3732} 3733 3734static int 3735symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 3736{ 3737 const Elf_Sym *def; 3738 const Obj_Entry *defobj; 3739 const Objlist_Entry *elm; 3740 SymLook req1; 3741 int res; 3742 3743 def = NULL; 3744 defobj = NULL; 3745 STAILQ_FOREACH(elm, objlist, link) { 3746 if (donelist_check(dlp, elm->obj)) 3747 continue; 3748 symlook_init_from_req(&req1, req); 3749 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 3750 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3751 def = req1.sym_out; 3752 defobj = req1.defobj_out; 3753 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3754 break; 3755 } 3756 } 3757 } 3758 if (def != NULL) { 3759 req->sym_out = def; 3760 req->defobj_out = defobj; 3761 return (0); 3762 } 3763 return (ESRCH); 3764} 3765 3766/* 3767 * Search the chain of DAGS cointed to by the given Needed_Entry 3768 * for a symbol of the given name. Each DAG is scanned completely 3769 * before advancing to the next one. Returns a pointer to the symbol, 3770 * or NULL if no definition was found. 3771 */ 3772static int 3773symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 3774{ 3775 const Elf_Sym *def; 3776 const Needed_Entry *n; 3777 const Obj_Entry *defobj; 3778 SymLook req1; 3779 int res; 3780 3781 def = NULL; 3782 defobj = NULL; 3783 symlook_init_from_req(&req1, req); 3784 for (n = needed; n != NULL; n = n->next) { 3785 if (n->obj == NULL || 3786 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 3787 continue; 3788 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3789 def = req1.sym_out; 3790 defobj = req1.defobj_out; 3791 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3792 break; 3793 } 3794 } 3795 if (def != NULL) { 3796 req->sym_out = def; 3797 req->defobj_out = defobj; 3798 return (0); 3799 } 3800 return (ESRCH); 3801} 3802 3803/* 3804 * Search the symbol table of a single shared object for a symbol of 3805 * the given name and version, if requested. Returns a pointer to the 3806 * symbol, or NULL if no definition was found. If the object is 3807 * filter, return filtered symbol from filtee. 3808 * 3809 * The symbol's hash value is passed in for efficiency reasons; that 3810 * eliminates many recomputations of the hash value. 3811 */ 3812int 3813symlook_obj(SymLook *req, const Obj_Entry *obj) 3814{ 3815 DoneList donelist; 3816 SymLook req1; 3817 int flags, res, mres; 3818 3819 /* 3820 * If there is at least one valid hash at this point, we prefer to 3821 * use the faster GNU version if available. 3822 */ 3823 if (obj->valid_hash_gnu) 3824 mres = symlook_obj1_gnu(req, obj); 3825 else if (obj->valid_hash_sysv) 3826 mres = symlook_obj1_sysv(req, obj); 3827 else 3828 return (EINVAL); 3829 3830 if (mres == 0) { 3831 if (obj->needed_filtees != NULL) { 3832 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3833 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3834 donelist_init(&donelist); 3835 symlook_init_from_req(&req1, req); 3836 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 3837 if (res == 0) { 3838 req->sym_out = req1.sym_out; 3839 req->defobj_out = req1.defobj_out; 3840 } 3841 return (res); 3842 } 3843 if (obj->needed_aux_filtees != NULL) { 3844 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3845 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3846 donelist_init(&donelist); 3847 symlook_init_from_req(&req1, req); 3848 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 3849 if (res == 0) { 3850 req->sym_out = req1.sym_out; 3851 req->defobj_out = req1.defobj_out; 3852 return (res); 3853 } 3854 } 3855 } 3856 return (mres); 3857} 3858 3859/* Symbol match routine common to both hash functions */ 3860static bool 3861matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 3862 const unsigned long symnum) 3863{ 3864 Elf_Versym verndx; 3865 const Elf_Sym *symp; 3866 const char *strp; 3867 3868 symp = obj->symtab + symnum; 3869 strp = obj->strtab + symp->st_name; 3870 3871 switch (ELF_ST_TYPE(symp->st_info)) { 3872 case STT_FUNC: 3873 case STT_NOTYPE: 3874 case STT_OBJECT: 3875 case STT_COMMON: 3876 case STT_GNU_IFUNC: 3877 if (symp->st_value == 0) 3878 return (false); 3879 /* fallthrough */ 3880 case STT_TLS: 3881 if (symp->st_shndx != SHN_UNDEF) 3882 break; 3883#ifndef __mips__ 3884 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 3885 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 3886 break; 3887 /* fallthrough */ 3888#endif 3889 default: 3890 return (false); 3891 } 3892 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 3893 return (false); 3894 3895 if (req->ventry == NULL) { 3896 if (obj->versyms != NULL) { 3897 verndx = VER_NDX(obj->versyms[symnum]); 3898 if (verndx > obj->vernum) { 3899 _rtld_error( 3900 "%s: symbol %s references wrong version %d", 3901 obj->path, obj->strtab + symnum, verndx); 3902 return (false); 3903 } 3904 /* 3905 * If we are not called from dlsym (i.e. this 3906 * is a normal relocation from unversioned 3907 * binary), accept the symbol immediately if 3908 * it happens to have first version after this 3909 * shared object became versioned. Otherwise, 3910 * if symbol is versioned and not hidden, 3911 * remember it. If it is the only symbol with 3912 * this name exported by the shared object, it 3913 * will be returned as a match by the calling 3914 * function. If symbol is global (verndx < 2) 3915 * accept it unconditionally. 3916 */ 3917 if ((req->flags & SYMLOOK_DLSYM) == 0 && 3918 verndx == VER_NDX_GIVEN) { 3919 result->sym_out = symp; 3920 return (true); 3921 } 3922 else if (verndx >= VER_NDX_GIVEN) { 3923 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 3924 == 0) { 3925 if (result->vsymp == NULL) 3926 result->vsymp = symp; 3927 result->vcount++; 3928 } 3929 return (false); 3930 } 3931 } 3932 result->sym_out = symp; 3933 return (true); 3934 } 3935 if (obj->versyms == NULL) { 3936 if (object_match_name(obj, req->ventry->name)) { 3937 _rtld_error("%s: object %s should provide version %s " 3938 "for symbol %s", obj_rtld.path, obj->path, 3939 req->ventry->name, obj->strtab + symnum); 3940 return (false); 3941 } 3942 } else { 3943 verndx = VER_NDX(obj->versyms[symnum]); 3944 if (verndx > obj->vernum) { 3945 _rtld_error("%s: symbol %s references wrong version %d", 3946 obj->path, obj->strtab + symnum, verndx); 3947 return (false); 3948 } 3949 if (obj->vertab[verndx].hash != req->ventry->hash || 3950 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 3951 /* 3952 * Version does not match. Look if this is a 3953 * global symbol and if it is not hidden. If 3954 * global symbol (verndx < 2) is available, 3955 * use it. Do not return symbol if we are 3956 * called by dlvsym, because dlvsym looks for 3957 * a specific version and default one is not 3958 * what dlvsym wants. 3959 */ 3960 if ((req->flags & SYMLOOK_DLSYM) || 3961 (verndx >= VER_NDX_GIVEN) || 3962 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 3963 return (false); 3964 } 3965 } 3966 result->sym_out = symp; 3967 return (true); 3968} 3969 3970/* 3971 * Search for symbol using SysV hash function. 3972 * obj->buckets is known not to be NULL at this point; the test for this was 3973 * performed with the obj->valid_hash_sysv assignment. 3974 */ 3975static int 3976symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 3977{ 3978 unsigned long symnum; 3979 Sym_Match_Result matchres; 3980 3981 matchres.sym_out = NULL; 3982 matchres.vsymp = NULL; 3983 matchres.vcount = 0; 3984 3985 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 3986 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 3987 if (symnum >= obj->nchains) 3988 return (ESRCH); /* Bad object */ 3989 3990 if (matched_symbol(req, obj, &matchres, symnum)) { 3991 req->sym_out = matchres.sym_out; 3992 req->defobj_out = obj; 3993 return (0); 3994 } 3995 } 3996 if (matchres.vcount == 1) { 3997 req->sym_out = matchres.vsymp; 3998 req->defobj_out = obj; 3999 return (0); 4000 } 4001 return (ESRCH); 4002} 4003 4004/* Search for symbol using GNU hash function */ 4005static int 4006symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4007{ 4008 Elf_Addr bloom_word; 4009 const Elf32_Word *hashval; 4010 Elf32_Word bucket; 4011 Sym_Match_Result matchres; 4012 unsigned int h1, h2; 4013 unsigned long symnum; 4014 4015 matchres.sym_out = NULL; 4016 matchres.vsymp = NULL; 4017 matchres.vcount = 0; 4018 4019 /* Pick right bitmask word from Bloom filter array */ 4020 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4021 obj->maskwords_bm_gnu]; 4022 4023 /* Calculate modulus word size of gnu hash and its derivative */ 4024 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4025 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4026 4027 /* Filter out the "definitely not in set" queries */ 4028 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4029 return (ESRCH); 4030 4031 /* Locate hash chain and corresponding value element*/ 4032 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4033 if (bucket == 0) 4034 return (ESRCH); 4035 hashval = &obj->chain_zero_gnu[bucket]; 4036 do { 4037 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4038 symnum = hashval - obj->chain_zero_gnu; 4039 if (matched_symbol(req, obj, &matchres, symnum)) { 4040 req->sym_out = matchres.sym_out; 4041 req->defobj_out = obj; 4042 return (0); 4043 } 4044 } 4045 } while ((*hashval++ & 1) == 0); 4046 if (matchres.vcount == 1) { 4047 req->sym_out = matchres.vsymp; 4048 req->defobj_out = obj; 4049 return (0); 4050 } 4051 return (ESRCH); 4052} 4053 4054static void 4055trace_loaded_objects(Obj_Entry *obj) 4056{ 4057 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4058 int c; 4059 4060 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 4061 main_local = ""; 4062 4063 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL) 4064 fmt1 = "\t%o => %p (%x)\n"; 4065 4066 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL) 4067 fmt2 = "\t%o (%x)\n"; 4068 4069 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL"); 4070 4071 for (; obj; obj = obj->next) { 4072 Needed_Entry *needed; 4073 char *name, *path; 4074 bool is_lib; 4075 4076 if (list_containers && obj->needed != NULL) 4077 rtld_printf("%s:\n", obj->path); 4078 for (needed = obj->needed; needed; needed = needed->next) { 4079 if (needed->obj != NULL) { 4080 if (needed->obj->traced && !list_containers) 4081 continue; 4082 needed->obj->traced = true; 4083 path = needed->obj->path; 4084 } else 4085 path = "not found"; 4086 4087 name = (char *)obj->strtab + needed->name; 4088 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4089 4090 fmt = is_lib ? fmt1 : fmt2; 4091 while ((c = *fmt++) != '\0') { 4092 switch (c) { 4093 default: 4094 rtld_putchar(c); 4095 continue; 4096 case '\\': 4097 switch (c = *fmt) { 4098 case '\0': 4099 continue; 4100 case 'n': 4101 rtld_putchar('\n'); 4102 break; 4103 case 't': 4104 rtld_putchar('\t'); 4105 break; 4106 } 4107 break; 4108 case '%': 4109 switch (c = *fmt) { 4110 case '\0': 4111 continue; 4112 case '%': 4113 default: 4114 rtld_putchar(c); 4115 break; 4116 case 'A': 4117 rtld_putstr(main_local); 4118 break; 4119 case 'a': 4120 rtld_putstr(obj_main->path); 4121 break; 4122 case 'o': 4123 rtld_putstr(name); 4124 break; 4125#if 0 4126 case 'm': 4127 rtld_printf("%d", sodp->sod_major); 4128 break; 4129 case 'n': 4130 rtld_printf("%d", sodp->sod_minor); 4131 break; 4132#endif 4133 case 'p': 4134 rtld_putstr(path); 4135 break; 4136 case 'x': 4137 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4138 0); 4139 break; 4140 } 4141 break; 4142 } 4143 ++fmt; 4144 } 4145 } 4146 } 4147} 4148 4149/* 4150 * Unload a dlopened object and its dependencies from memory and from 4151 * our data structures. It is assumed that the DAG rooted in the 4152 * object has already been unreferenced, and that the object has a 4153 * reference count of 0. 4154 */ 4155static void 4156unload_object(Obj_Entry *root) 4157{ 4158 Obj_Entry *obj; 4159 Obj_Entry **linkp; 4160 4161 assert(root->refcount == 0); 4162 4163 /* 4164 * Pass over the DAG removing unreferenced objects from 4165 * appropriate lists. 4166 */ 4167 unlink_object(root); 4168 4169 /* Unmap all objects that are no longer referenced. */ 4170 linkp = &obj_list->next; 4171 while ((obj = *linkp) != NULL) { 4172 if (obj->refcount == 0) { 4173 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 4174 obj->path); 4175 dbg("unloading \"%s\"", obj->path); 4176 unload_filtees(root); 4177 munmap(obj->mapbase, obj->mapsize); 4178 linkmap_delete(obj); 4179 *linkp = obj->next; 4180 obj_count--; 4181 obj_free(obj); 4182 } else 4183 linkp = &obj->next; 4184 } 4185 obj_tail = linkp; 4186} 4187 4188static void 4189unlink_object(Obj_Entry *root) 4190{ 4191 Objlist_Entry *elm; 4192 4193 if (root->refcount == 0) { 4194 /* Remove the object from the RTLD_GLOBAL list. */ 4195 objlist_remove(&list_global, root); 4196 4197 /* Remove the object from all objects' DAG lists. */ 4198 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4199 objlist_remove(&elm->obj->dldags, root); 4200 if (elm->obj != root) 4201 unlink_object(elm->obj); 4202 } 4203 } 4204} 4205 4206static void 4207ref_dag(Obj_Entry *root) 4208{ 4209 Objlist_Entry *elm; 4210 4211 assert(root->dag_inited); 4212 STAILQ_FOREACH(elm, &root->dagmembers, link) 4213 elm->obj->refcount++; 4214} 4215 4216static void 4217unref_dag(Obj_Entry *root) 4218{ 4219 Objlist_Entry *elm; 4220 4221 assert(root->dag_inited); 4222 STAILQ_FOREACH(elm, &root->dagmembers, link) 4223 elm->obj->refcount--; 4224} 4225 4226/* 4227 * Common code for MD __tls_get_addr(). 4228 */ 4229static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4230static void * 4231tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4232{ 4233 Elf_Addr *newdtv, *dtv; 4234 RtldLockState lockstate; 4235 int to_copy; 4236 4237 dtv = *dtvp; 4238 /* Check dtv generation in case new modules have arrived */ 4239 if (dtv[0] != tls_dtv_generation) { 4240 wlock_acquire(rtld_bind_lock, &lockstate); 4241 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4242 to_copy = dtv[1]; 4243 if (to_copy > tls_max_index) 4244 to_copy = tls_max_index; 4245 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4246 newdtv[0] = tls_dtv_generation; 4247 newdtv[1] = tls_max_index; 4248 free(dtv); 4249 lock_release(rtld_bind_lock, &lockstate); 4250 dtv = *dtvp = newdtv; 4251 } 4252 4253 /* Dynamically allocate module TLS if necessary */ 4254 if (dtv[index + 1] == 0) { 4255 /* Signal safe, wlock will block out signals. */ 4256 wlock_acquire(rtld_bind_lock, &lockstate); 4257 if (!dtv[index + 1]) 4258 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4259 lock_release(rtld_bind_lock, &lockstate); 4260 } 4261 return ((void *)(dtv[index + 1] + offset)); 4262} 4263 4264void * 4265tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4266{ 4267 Elf_Addr *dtv; 4268 4269 dtv = *dtvp; 4270 /* Check dtv generation in case new modules have arrived */ 4271 if (__predict_true(dtv[0] == tls_dtv_generation && 4272 dtv[index + 1] != 0)) 4273 return ((void *)(dtv[index + 1] + offset)); 4274 return (tls_get_addr_slow(dtvp, index, offset)); 4275} 4276 4277#if defined(__arm__) || defined(__ia64__) || defined(__mips__) || defined(__powerpc__) 4278 4279/* 4280 * Allocate Static TLS using the Variant I method. 4281 */ 4282void * 4283allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4284{ 4285 Obj_Entry *obj; 4286 char *tcb; 4287 Elf_Addr **tls; 4288 Elf_Addr *dtv; 4289 Elf_Addr addr; 4290 int i; 4291 4292 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4293 return (oldtcb); 4294 4295 assert(tcbsize >= TLS_TCB_SIZE); 4296 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 4297 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 4298 4299 if (oldtcb != NULL) { 4300 memcpy(tls, oldtcb, tls_static_space); 4301 free(oldtcb); 4302 4303 /* Adjust the DTV. */ 4304 dtv = tls[0]; 4305 for (i = 0; i < dtv[1]; i++) { 4306 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4307 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4308 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 4309 } 4310 } 4311 } else { 4312 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4313 tls[0] = dtv; 4314 dtv[0] = tls_dtv_generation; 4315 dtv[1] = tls_max_index; 4316 4317 for (obj = objs; obj; obj = obj->next) { 4318 if (obj->tlsoffset > 0) { 4319 addr = (Elf_Addr)tls + obj->tlsoffset; 4320 if (obj->tlsinitsize > 0) 4321 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4322 if (obj->tlssize > obj->tlsinitsize) 4323 memset((void*) (addr + obj->tlsinitsize), 0, 4324 obj->tlssize - obj->tlsinitsize); 4325 dtv[obj->tlsindex + 1] = addr; 4326 } 4327 } 4328 } 4329 4330 return (tcb); 4331} 4332 4333void 4334free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4335{ 4336 Elf_Addr *dtv; 4337 Elf_Addr tlsstart, tlsend; 4338 int dtvsize, i; 4339 4340 assert(tcbsize >= TLS_TCB_SIZE); 4341 4342 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 4343 tlsend = tlsstart + tls_static_space; 4344 4345 dtv = *(Elf_Addr **)tlsstart; 4346 dtvsize = dtv[1]; 4347 for (i = 0; i < dtvsize; i++) { 4348 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4349 free((void*)dtv[i+2]); 4350 } 4351 } 4352 free(dtv); 4353 free(tcb); 4354} 4355 4356#endif 4357 4358#if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 4359 4360/* 4361 * Allocate Static TLS using the Variant II method. 4362 */ 4363void * 4364allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4365{ 4366 Obj_Entry *obj; 4367 size_t size, ralign; 4368 char *tls; 4369 Elf_Addr *dtv, *olddtv; 4370 Elf_Addr segbase, oldsegbase, addr; 4371 int i; 4372 4373 ralign = tcbalign; 4374 if (tls_static_max_align > ralign) 4375 ralign = tls_static_max_align; 4376 size = round(tls_static_space, ralign) + round(tcbsize, ralign); 4377 4378 assert(tcbsize >= 2*sizeof(Elf_Addr)); 4379 tls = malloc_aligned(size, ralign); 4380 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4381 4382 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign)); 4383 ((Elf_Addr*)segbase)[0] = segbase; 4384 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 4385 4386 dtv[0] = tls_dtv_generation; 4387 dtv[1] = tls_max_index; 4388 4389 if (oldtls) { 4390 /* 4391 * Copy the static TLS block over whole. 4392 */ 4393 oldsegbase = (Elf_Addr) oldtls; 4394 memcpy((void *)(segbase - tls_static_space), 4395 (const void *)(oldsegbase - tls_static_space), 4396 tls_static_space); 4397 4398 /* 4399 * If any dynamic TLS blocks have been created tls_get_addr(), 4400 * move them over. 4401 */ 4402 olddtv = ((Elf_Addr**)oldsegbase)[1]; 4403 for (i = 0; i < olddtv[1]; i++) { 4404 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 4405 dtv[i+2] = olddtv[i+2]; 4406 olddtv[i+2] = 0; 4407 } 4408 } 4409 4410 /* 4411 * We assume that this block was the one we created with 4412 * allocate_initial_tls(). 4413 */ 4414 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 4415 } else { 4416 for (obj = objs; obj; obj = obj->next) { 4417 if (obj->tlsoffset) { 4418 addr = segbase - obj->tlsoffset; 4419 memset((void*) (addr + obj->tlsinitsize), 4420 0, obj->tlssize - obj->tlsinitsize); 4421 if (obj->tlsinit) 4422 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4423 dtv[obj->tlsindex + 1] = addr; 4424 } 4425 } 4426 } 4427 4428 return (void*) segbase; 4429} 4430 4431void 4432free_tls(void *tls, size_t tcbsize, size_t tcbalign) 4433{ 4434 Elf_Addr* dtv; 4435 size_t size, ralign; 4436 int dtvsize, i; 4437 Elf_Addr tlsstart, tlsend; 4438 4439 /* 4440 * Figure out the size of the initial TLS block so that we can 4441 * find stuff which ___tls_get_addr() allocated dynamically. 4442 */ 4443 ralign = tcbalign; 4444 if (tls_static_max_align > ralign) 4445 ralign = tls_static_max_align; 4446 size = round(tls_static_space, ralign); 4447 4448 dtv = ((Elf_Addr**)tls)[1]; 4449 dtvsize = dtv[1]; 4450 tlsend = (Elf_Addr) tls; 4451 tlsstart = tlsend - size; 4452 for (i = 0; i < dtvsize; i++) { 4453 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 4454 free_aligned((void *)dtv[i + 2]); 4455 } 4456 } 4457 4458 free_aligned((void *)tlsstart); 4459 free((void*) dtv); 4460} 4461 4462#endif 4463 4464/* 4465 * Allocate TLS block for module with given index. 4466 */ 4467void * 4468allocate_module_tls(int index) 4469{ 4470 Obj_Entry* obj; 4471 char* p; 4472 4473 for (obj = obj_list; obj; obj = obj->next) { 4474 if (obj->tlsindex == index) 4475 break; 4476 } 4477 if (!obj) { 4478 _rtld_error("Can't find module with TLS index %d", index); 4479 die(); 4480 } 4481 4482 p = malloc_aligned(obj->tlssize, obj->tlsalign); 4483 memcpy(p, obj->tlsinit, obj->tlsinitsize); 4484 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 4485 4486 return p; 4487} 4488 4489bool 4490allocate_tls_offset(Obj_Entry *obj) 4491{ 4492 size_t off; 4493 4494 if (obj->tls_done) 4495 return true; 4496 4497 if (obj->tlssize == 0) { 4498 obj->tls_done = true; 4499 return true; 4500 } 4501 4502 if (obj->tlsindex == 1) 4503 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 4504 else 4505 off = calculate_tls_offset(tls_last_offset, tls_last_size, 4506 obj->tlssize, obj->tlsalign); 4507 4508 /* 4509 * If we have already fixed the size of the static TLS block, we 4510 * must stay within that size. When allocating the static TLS, we 4511 * leave a small amount of space spare to be used for dynamically 4512 * loading modules which use static TLS. 4513 */ 4514 if (tls_static_space != 0) { 4515 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 4516 return false; 4517 } else if (obj->tlsalign > tls_static_max_align) { 4518 tls_static_max_align = obj->tlsalign; 4519 } 4520 4521 tls_last_offset = obj->tlsoffset = off; 4522 tls_last_size = obj->tlssize; 4523 obj->tls_done = true; 4524 4525 return true; 4526} 4527 4528void 4529free_tls_offset(Obj_Entry *obj) 4530{ 4531 4532 /* 4533 * If we were the last thing to allocate out of the static TLS 4534 * block, we give our space back to the 'allocator'. This is a 4535 * simplistic workaround to allow libGL.so.1 to be loaded and 4536 * unloaded multiple times. 4537 */ 4538 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 4539 == calculate_tls_end(tls_last_offset, tls_last_size)) { 4540 tls_last_offset -= obj->tlssize; 4541 tls_last_size = 0; 4542 } 4543} 4544 4545void * 4546_rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 4547{ 4548 void *ret; 4549 RtldLockState lockstate; 4550 4551 wlock_acquire(rtld_bind_lock, &lockstate); 4552 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign); 4553 lock_release(rtld_bind_lock, &lockstate); 4554 return (ret); 4555} 4556 4557void 4558_rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4559{ 4560 RtldLockState lockstate; 4561 4562 wlock_acquire(rtld_bind_lock, &lockstate); 4563 free_tls(tcb, tcbsize, tcbalign); 4564 lock_release(rtld_bind_lock, &lockstate); 4565} 4566 4567static void 4568object_add_name(Obj_Entry *obj, const char *name) 4569{ 4570 Name_Entry *entry; 4571 size_t len; 4572 4573 len = strlen(name); 4574 entry = malloc(sizeof(Name_Entry) + len); 4575 4576 if (entry != NULL) { 4577 strcpy(entry->name, name); 4578 STAILQ_INSERT_TAIL(&obj->names, entry, link); 4579 } 4580} 4581 4582static int 4583object_match_name(const Obj_Entry *obj, const char *name) 4584{ 4585 Name_Entry *entry; 4586 4587 STAILQ_FOREACH(entry, &obj->names, link) { 4588 if (strcmp(name, entry->name) == 0) 4589 return (1); 4590 } 4591 return (0); 4592} 4593 4594static Obj_Entry * 4595locate_dependency(const Obj_Entry *obj, const char *name) 4596{ 4597 const Objlist_Entry *entry; 4598 const Needed_Entry *needed; 4599 4600 STAILQ_FOREACH(entry, &list_main, link) { 4601 if (object_match_name(entry->obj, name)) 4602 return entry->obj; 4603 } 4604 4605 for (needed = obj->needed; needed != NULL; needed = needed->next) { 4606 if (strcmp(obj->strtab + needed->name, name) == 0 || 4607 (needed->obj != NULL && object_match_name(needed->obj, name))) { 4608 /* 4609 * If there is DT_NEEDED for the name we are looking for, 4610 * we are all set. Note that object might not be found if 4611 * dependency was not loaded yet, so the function can 4612 * return NULL here. This is expected and handled 4613 * properly by the caller. 4614 */ 4615 return (needed->obj); 4616 } 4617 } 4618 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 4619 obj->path, name); 4620 die(); 4621} 4622 4623static int 4624check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 4625 const Elf_Vernaux *vna) 4626{ 4627 const Elf_Verdef *vd; 4628 const char *vername; 4629 4630 vername = refobj->strtab + vna->vna_name; 4631 vd = depobj->verdef; 4632 if (vd == NULL) { 4633 _rtld_error("%s: version %s required by %s not defined", 4634 depobj->path, vername, refobj->path); 4635 return (-1); 4636 } 4637 for (;;) { 4638 if (vd->vd_version != VER_DEF_CURRENT) { 4639 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4640 depobj->path, vd->vd_version); 4641 return (-1); 4642 } 4643 if (vna->vna_hash == vd->vd_hash) { 4644 const Elf_Verdaux *aux = (const Elf_Verdaux *) 4645 ((char *)vd + vd->vd_aux); 4646 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 4647 return (0); 4648 } 4649 if (vd->vd_next == 0) 4650 break; 4651 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4652 } 4653 if (vna->vna_flags & VER_FLG_WEAK) 4654 return (0); 4655 _rtld_error("%s: version %s required by %s not found", 4656 depobj->path, vername, refobj->path); 4657 return (-1); 4658} 4659 4660static int 4661rtld_verify_object_versions(Obj_Entry *obj) 4662{ 4663 const Elf_Verneed *vn; 4664 const Elf_Verdef *vd; 4665 const Elf_Verdaux *vda; 4666 const Elf_Vernaux *vna; 4667 const Obj_Entry *depobj; 4668 int maxvernum, vernum; 4669 4670 if (obj->ver_checked) 4671 return (0); 4672 obj->ver_checked = true; 4673 4674 maxvernum = 0; 4675 /* 4676 * Walk over defined and required version records and figure out 4677 * max index used by any of them. Do very basic sanity checking 4678 * while there. 4679 */ 4680 vn = obj->verneed; 4681 while (vn != NULL) { 4682 if (vn->vn_version != VER_NEED_CURRENT) { 4683 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 4684 obj->path, vn->vn_version); 4685 return (-1); 4686 } 4687 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4688 for (;;) { 4689 vernum = VER_NEED_IDX(vna->vna_other); 4690 if (vernum > maxvernum) 4691 maxvernum = vernum; 4692 if (vna->vna_next == 0) 4693 break; 4694 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4695 } 4696 if (vn->vn_next == 0) 4697 break; 4698 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4699 } 4700 4701 vd = obj->verdef; 4702 while (vd != NULL) { 4703 if (vd->vd_version != VER_DEF_CURRENT) { 4704 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4705 obj->path, vd->vd_version); 4706 return (-1); 4707 } 4708 vernum = VER_DEF_IDX(vd->vd_ndx); 4709 if (vernum > maxvernum) 4710 maxvernum = vernum; 4711 if (vd->vd_next == 0) 4712 break; 4713 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4714 } 4715 4716 if (maxvernum == 0) 4717 return (0); 4718 4719 /* 4720 * Store version information in array indexable by version index. 4721 * Verify that object version requirements are satisfied along the 4722 * way. 4723 */ 4724 obj->vernum = maxvernum + 1; 4725 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 4726 4727 vd = obj->verdef; 4728 while (vd != NULL) { 4729 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 4730 vernum = VER_DEF_IDX(vd->vd_ndx); 4731 assert(vernum <= maxvernum); 4732 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 4733 obj->vertab[vernum].hash = vd->vd_hash; 4734 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 4735 obj->vertab[vernum].file = NULL; 4736 obj->vertab[vernum].flags = 0; 4737 } 4738 if (vd->vd_next == 0) 4739 break; 4740 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4741 } 4742 4743 vn = obj->verneed; 4744 while (vn != NULL) { 4745 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 4746 if (depobj == NULL) 4747 return (-1); 4748 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4749 for (;;) { 4750 if (check_object_provided_version(obj, depobj, vna)) 4751 return (-1); 4752 vernum = VER_NEED_IDX(vna->vna_other); 4753 assert(vernum <= maxvernum); 4754 obj->vertab[vernum].hash = vna->vna_hash; 4755 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 4756 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 4757 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 4758 VER_INFO_HIDDEN : 0; 4759 if (vna->vna_next == 0) 4760 break; 4761 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4762 } 4763 if (vn->vn_next == 0) 4764 break; 4765 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4766 } 4767 return 0; 4768} 4769 4770static int 4771rtld_verify_versions(const Objlist *objlist) 4772{ 4773 Objlist_Entry *entry; 4774 int rc; 4775 4776 rc = 0; 4777 STAILQ_FOREACH(entry, objlist, link) { 4778 /* 4779 * Skip dummy objects or objects that have their version requirements 4780 * already checked. 4781 */ 4782 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 4783 continue; 4784 if (rtld_verify_object_versions(entry->obj) == -1) { 4785 rc = -1; 4786 if (ld_tracing == NULL) 4787 break; 4788 } 4789 } 4790 if (rc == 0 || ld_tracing != NULL) 4791 rc = rtld_verify_object_versions(&obj_rtld); 4792 return rc; 4793} 4794 4795const Ver_Entry * 4796fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 4797{ 4798 Elf_Versym vernum; 4799 4800 if (obj->vertab) { 4801 vernum = VER_NDX(obj->versyms[symnum]); 4802 if (vernum >= obj->vernum) { 4803 _rtld_error("%s: symbol %s has wrong verneed value %d", 4804 obj->path, obj->strtab + symnum, vernum); 4805 } else if (obj->vertab[vernum].hash != 0) { 4806 return &obj->vertab[vernum]; 4807 } 4808 } 4809 return NULL; 4810} 4811 4812int 4813_rtld_get_stack_prot(void) 4814{ 4815 4816 return (stack_prot); 4817} 4818 4819int 4820_rtld_is_dlopened(void *arg) 4821{ 4822 Obj_Entry *obj; 4823 RtldLockState lockstate; 4824 int res; 4825 4826 rlock_acquire(rtld_bind_lock, &lockstate); 4827 obj = dlcheck(arg); 4828 if (obj == NULL) 4829 obj = obj_from_addr(arg); 4830 if (obj == NULL) { 4831 _rtld_error("No shared object contains address"); 4832 lock_release(rtld_bind_lock, &lockstate); 4833 return (-1); 4834 } 4835 res = obj->dlopened ? 1 : 0; 4836 lock_release(rtld_bind_lock, &lockstate); 4837 return (res); 4838} 4839 4840static void 4841map_stacks_exec(RtldLockState *lockstate) 4842{ 4843 void (*thr_map_stacks_exec)(void); 4844 4845 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 4846 return; 4847 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 4848 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 4849 if (thr_map_stacks_exec != NULL) { 4850 stack_prot |= PROT_EXEC; 4851 thr_map_stacks_exec(); 4852 } 4853} 4854 4855void 4856symlook_init(SymLook *dst, const char *name) 4857{ 4858 4859 bzero(dst, sizeof(*dst)); 4860 dst->name = name; 4861 dst->hash = elf_hash(name); 4862 dst->hash_gnu = gnu_hash(name); 4863} 4864 4865static void 4866symlook_init_from_req(SymLook *dst, const SymLook *src) 4867{ 4868 4869 dst->name = src->name; 4870 dst->hash = src->hash; 4871 dst->hash_gnu = src->hash_gnu; 4872 dst->ventry = src->ventry; 4873 dst->flags = src->flags; 4874 dst->defobj_out = NULL; 4875 dst->sym_out = NULL; 4876 dst->lockstate = src->lockstate; 4877} 4878 4879/* 4880 * Overrides for libc_pic-provided functions. 4881 */ 4882 4883int 4884__getosreldate(void) 4885{ 4886 size_t len; 4887 int oid[2]; 4888 int error, osrel; 4889 4890 if (osreldate != 0) 4891 return (osreldate); 4892 4893 oid[0] = CTL_KERN; 4894 oid[1] = KERN_OSRELDATE; 4895 osrel = 0; 4896 len = sizeof(osrel); 4897 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 4898 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 4899 osreldate = osrel; 4900 return (osreldate); 4901} 4902 4903void 4904exit(int status) 4905{ 4906 4907 _exit(status); 4908} 4909 4910void (*__cleanup)(void); 4911int __isthreaded = 0; 4912int _thread_autoinit_dummy_decl = 1; 4913 4914/* 4915 * No unresolved symbols for rtld. 4916 */ 4917void 4918__pthread_cxa_finalize(struct dl_phdr_info *a) 4919{ 4920} 4921 4922void 4923__stack_chk_fail(void) 4924{ 4925 4926 _rtld_error("stack overflow detected; terminated"); 4927 die(); 4928} 4929__weak_reference(__stack_chk_fail, __stack_chk_fail_local); 4930 4931void 4932__chk_fail(void) 4933{ 4934 4935 _rtld_error("buffer overflow detected; terminated"); 4936 die(); 4937} 4938 4939const char * 4940rtld_strerror(int errnum) 4941{ 4942 4943 if (errnum < 0 || errnum >= sys_nerr) 4944 return ("Unknown error"); 4945 return (sys_errlist[errnum]); 4946} 4947