rtld.c revision 282118
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 282118 2015-04-28 01:15:17Z emaste $ 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 digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 82 const Elf_Dyn **, const Elf_Dyn **); 83static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *, 84 const Elf_Dyn *); 85static void digest_dynamic(Obj_Entry *, int); 86static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 87static Obj_Entry *dlcheck(void *); 88static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, 89 int lo_flags, int mode, RtldLockState *lockstate); 90static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 91static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 92static bool donelist_check(DoneList *, const Obj_Entry *); 93static void errmsg_restore(char *); 94static char *errmsg_save(void); 95static void *fill_search_info(const char *, size_t, void *); 96static char *find_library(const char *, const Obj_Entry *); 97static const char *gethints(bool); 98static void init_dag(Obj_Entry *); 99static void init_pagesizes(Elf_Auxinfo **aux_info); 100static void init_rtld(caddr_t, Elf_Auxinfo **); 101static void initlist_add_neededs(Needed_Entry *, Objlist *); 102static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *); 103static void linkmap_add(Obj_Entry *); 104static void linkmap_delete(Obj_Entry *); 105static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 106static void unload_filtees(Obj_Entry *); 107static int load_needed_objects(Obj_Entry *, int); 108static int load_preload_objects(void); 109static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 110static void map_stacks_exec(RtldLockState *); 111static Obj_Entry *obj_from_addr(const void *); 112static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 113static void objlist_call_init(Objlist *, RtldLockState *); 114static void objlist_clear(Objlist *); 115static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 116static void objlist_init(Objlist *); 117static void objlist_push_head(Objlist *, Obj_Entry *); 118static void objlist_push_tail(Objlist *, Obj_Entry *); 119static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 120static void objlist_remove(Objlist *, Obj_Entry *); 121static void *path_enumerate(const char *, path_enum_proc, void *); 122static int relocate_object_dag(Obj_Entry *root, bool bind_now, 123 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 124static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 125 int flags, RtldLockState *lockstate); 126static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 127 RtldLockState *); 128static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now, 129 int flags, RtldLockState *lockstate); 130static int rtld_dirname(const char *, char *); 131static int rtld_dirname_abs(const char *, char *); 132static void *rtld_dlopen(const char *name, int fd, int mode); 133static void rtld_exit(void); 134static char *search_library_path(const char *, const char *); 135static const void **get_program_var_addr(const char *, RtldLockState *); 136static void set_program_var(const char *, const void *); 137static int symlook_default(SymLook *, const Obj_Entry *refobj); 138static int symlook_global(SymLook *, DoneList *); 139static void symlook_init_from_req(SymLook *, const SymLook *); 140static int symlook_list(SymLook *, const Objlist *, DoneList *); 141static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 142static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 143static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 144static void trace_loaded_objects(Obj_Entry *); 145static void unlink_object(Obj_Entry *); 146static void unload_object(Obj_Entry *); 147static void unref_dag(Obj_Entry *); 148static void ref_dag(Obj_Entry *); 149static char *origin_subst_one(char *, const char *, const char *, bool); 150static char *origin_subst(char *, const char *); 151static void preinit_main(void); 152static int rtld_verify_versions(const Objlist *); 153static int rtld_verify_object_versions(Obj_Entry *); 154static void object_add_name(Obj_Entry *, const char *); 155static int object_match_name(const Obj_Entry *, const char *); 156static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 157static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 158 struct dl_phdr_info *phdr_info); 159static uint32_t gnu_hash(const char *); 160static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 161 const unsigned long); 162 163void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported; 164void _r_debug_postinit(struct link_map *) __noinline __exported; 165 166/* 167 * Data declarations. 168 */ 169static char *error_message; /* Message for dlerror(), or NULL */ 170struct r_debug r_debug __exported; /* for GDB; */ 171static bool libmap_disable; /* Disable libmap */ 172static bool ld_loadfltr; /* Immediate filters processing */ 173static char *libmap_override; /* Maps to use in addition to libmap.conf */ 174static bool trust; /* False for setuid and setgid programs */ 175static bool dangerous_ld_env; /* True if environment variables have been 176 used to affect the libraries loaded */ 177static char *ld_bind_now; /* Environment variable for immediate binding */ 178static char *ld_debug; /* Environment variable for debugging */ 179static char *ld_library_path; /* Environment variable for search path */ 180static char *ld_preload; /* Environment variable for libraries to 181 load first */ 182static char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 183static char *ld_tracing; /* Called from ldd to print libs */ 184static char *ld_utrace; /* Use utrace() to log events. */ 185static Obj_Entry *obj_list; /* Head of linked list of shared objects */ 186static Obj_Entry **obj_tail; /* Link field of last object in list */ 187static Obj_Entry *obj_main; /* The main program shared object */ 188static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 189static unsigned int obj_count; /* Number of objects in obj_list */ 190static unsigned int obj_loads; /* Number of objects in obj_list */ 191 192static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 193 STAILQ_HEAD_INITIALIZER(list_global); 194static Objlist list_main = /* Objects loaded at program startup */ 195 STAILQ_HEAD_INITIALIZER(list_main); 196static Objlist list_fini = /* Objects needing fini() calls */ 197 STAILQ_HEAD_INITIALIZER(list_fini); 198 199Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 200 201#define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 202 203extern Elf_Dyn _DYNAMIC; 204#pragma weak _DYNAMIC 205#ifndef RTLD_IS_DYNAMIC 206#define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL) 207#endif 208 209int dlclose(void *) __exported; 210char *dlerror(void) __exported; 211void *dlopen(const char *, int) __exported; 212void *fdlopen(int, int) __exported; 213void *dlsym(void *, const char *) __exported; 214dlfunc_t dlfunc(void *, const char *) __exported; 215void *dlvsym(void *, const char *, const char *) __exported; 216int dladdr(const void *, Dl_info *) __exported; 217void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *), 218 void (*)(void *), void (*)(void *), void (*)(void *)) __exported; 219int dlinfo(void *, int , void *) __exported; 220int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported; 221int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported; 222int _rtld_get_stack_prot(void) __exported; 223int _rtld_is_dlopened(void *) __exported; 224void _rtld_error(const char *, ...) __exported; 225 226int npagesizes, osreldate; 227size_t *pagesizes; 228 229long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0}; 230 231static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 232static int max_stack_flags; 233 234/* 235 * Global declarations normally provided by crt1. The dynamic linker is 236 * not built with crt1, so we have to provide them ourselves. 237 */ 238char *__progname; 239char **environ; 240 241/* 242 * Used to pass argc, argv to init functions. 243 */ 244int main_argc; 245char **main_argv; 246 247/* 248 * Globals to control TLS allocation. 249 */ 250size_t tls_last_offset; /* Static TLS offset of last module */ 251size_t tls_last_size; /* Static TLS size of last module */ 252size_t tls_static_space; /* Static TLS space allocated */ 253size_t tls_static_max_align; 254int tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 255int tls_max_index = 1; /* Largest module index allocated */ 256 257bool ld_library_path_rpath = false; 258 259/* 260 * Fill in a DoneList with an allocation large enough to hold all of 261 * the currently-loaded objects. Keep this as a macro since it calls 262 * alloca and we want that to occur within the scope of the caller. 263 */ 264#define donelist_init(dlp) \ 265 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 266 assert((dlp)->objs != NULL), \ 267 (dlp)->num_alloc = obj_count, \ 268 (dlp)->num_used = 0) 269 270#define UTRACE_DLOPEN_START 1 271#define UTRACE_DLOPEN_STOP 2 272#define UTRACE_DLCLOSE_START 3 273#define UTRACE_DLCLOSE_STOP 4 274#define UTRACE_LOAD_OBJECT 5 275#define UTRACE_UNLOAD_OBJECT 6 276#define UTRACE_ADD_RUNDEP 7 277#define UTRACE_PRELOAD_FINISHED 8 278#define UTRACE_INIT_CALL 9 279#define UTRACE_FINI_CALL 10 280 281struct utrace_rtld { 282 char sig[4]; /* 'RTLD' */ 283 int event; 284 void *handle; 285 void *mapbase; /* Used for 'parent' and 'init/fini' */ 286 size_t mapsize; 287 int refcnt; /* Used for 'mode' */ 288 char name[MAXPATHLEN]; 289}; 290 291#define LD_UTRACE(e, h, mb, ms, r, n) do { \ 292 if (ld_utrace != NULL) \ 293 ld_utrace_log(e, h, mb, ms, r, n); \ 294} while (0) 295 296static void 297ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 298 int refcnt, const char *name) 299{ 300 struct utrace_rtld ut; 301 302 ut.sig[0] = 'R'; 303 ut.sig[1] = 'T'; 304 ut.sig[2] = 'L'; 305 ut.sig[3] = 'D'; 306 ut.event = event; 307 ut.handle = handle; 308 ut.mapbase = mapbase; 309 ut.mapsize = mapsize; 310 ut.refcnt = refcnt; 311 bzero(ut.name, sizeof(ut.name)); 312 if (name) 313 strlcpy(ut.name, name, sizeof(ut.name)); 314 utrace(&ut, sizeof(ut)); 315} 316 317/* 318 * Main entry point for dynamic linking. The first argument is the 319 * stack pointer. The stack is expected to be laid out as described 320 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 321 * Specifically, the stack pointer points to a word containing 322 * ARGC. Following that in the stack is a null-terminated sequence 323 * of pointers to argument strings. Then comes a null-terminated 324 * sequence of pointers to environment strings. Finally, there is a 325 * sequence of "auxiliary vector" entries. 326 * 327 * The second argument points to a place to store the dynamic linker's 328 * exit procedure pointer and the third to a place to store the main 329 * program's object. 330 * 331 * The return value is the main program's entry point. 332 */ 333func_ptr_type 334_rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 335{ 336 Elf_Auxinfo *aux_info[AT_COUNT]; 337 int i; 338 int argc; 339 char **argv; 340 char **env; 341 Elf_Auxinfo *aux; 342 Elf_Auxinfo *auxp; 343 const char *argv0; 344 Objlist_Entry *entry; 345 Obj_Entry *obj; 346 Obj_Entry **preload_tail; 347 Obj_Entry *last_interposer; 348 Objlist initlist; 349 RtldLockState lockstate; 350 char *library_path_rpath; 351 int mib[2]; 352 size_t len; 353 354 /* 355 * On entry, the dynamic linker itself has not been relocated yet. 356 * Be very careful not to reference any global data until after 357 * init_rtld has returned. It is OK to reference file-scope statics 358 * and string constants, and to call static and global functions. 359 */ 360 361 /* Find the auxiliary vector on the stack. */ 362 argc = *sp++; 363 argv = (char **) sp; 364 sp += argc + 1; /* Skip over arguments and NULL terminator */ 365 env = (char **) sp; 366 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 367 ; 368 aux = (Elf_Auxinfo *) sp; 369 370 /* Digest the auxiliary vector. */ 371 for (i = 0; i < AT_COUNT; i++) 372 aux_info[i] = NULL; 373 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 374 if (auxp->a_type < AT_COUNT) 375 aux_info[auxp->a_type] = auxp; 376 } 377 378 /* Initialize and relocate ourselves. */ 379 assert(aux_info[AT_BASE] != NULL); 380 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 381 382 __progname = obj_rtld.path; 383 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 384 environ = env; 385 main_argc = argc; 386 main_argv = argv; 387 388 if (aux_info[AT_CANARY] != NULL && 389 aux_info[AT_CANARY]->a_un.a_ptr != NULL) { 390 i = aux_info[AT_CANARYLEN]->a_un.a_val; 391 if (i > sizeof(__stack_chk_guard)) 392 i = sizeof(__stack_chk_guard); 393 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i); 394 } else { 395 mib[0] = CTL_KERN; 396 mib[1] = KERN_ARND; 397 398 len = sizeof(__stack_chk_guard); 399 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 || 400 len != sizeof(__stack_chk_guard)) { 401 /* If sysctl was unsuccessful, use the "terminator canary". */ 402 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0; 403 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0; 404 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n'; 405 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255; 406 } 407 } 408 409 trust = !issetugid(); 410 411 ld_bind_now = getenv(LD_ "BIND_NOW"); 412 /* 413 * If the process is tainted, then we un-set the dangerous environment 414 * variables. The process will be marked as tainted until setuid(2) 415 * is called. If any child process calls setuid(2) we do not want any 416 * future processes to honor the potentially un-safe variables. 417 */ 418 if (!trust) { 419 if (unsetenv(LD_ "PRELOAD") || unsetenv(LD_ "LIBMAP") || 420 unsetenv(LD_ "LIBRARY_PATH") || unsetenv(LD_ "LIBMAP_DISABLE") || 421 unsetenv(LD_ "DEBUG") || unsetenv(LD_ "ELF_HINTS_PATH") || 422 unsetenv(LD_ "LOADFLTR") || unsetenv(LD_ "LIBRARY_PATH_RPATH")) { 423 _rtld_error("environment corrupt; aborting"); 424 rtld_die(); 425 } 426 } 427 ld_debug = getenv(LD_ "DEBUG"); 428 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL; 429 libmap_override = getenv(LD_ "LIBMAP"); 430 ld_library_path = getenv(LD_ "LIBRARY_PATH"); 431 ld_preload = getenv(LD_ "PRELOAD"); 432 ld_elf_hints_path = getenv(LD_ "ELF_HINTS_PATH"); 433 ld_loadfltr = getenv(LD_ "LOADFLTR") != NULL; 434 library_path_rpath = getenv(LD_ "LIBRARY_PATH_RPATH"); 435 if (library_path_rpath != NULL) { 436 if (library_path_rpath[0] == 'y' || 437 library_path_rpath[0] == 'Y' || 438 library_path_rpath[0] == '1') 439 ld_library_path_rpath = true; 440 else 441 ld_library_path_rpath = false; 442 } 443 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 444 (ld_library_path != NULL) || (ld_preload != NULL) || 445 (ld_elf_hints_path != NULL) || ld_loadfltr; 446 ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS"); 447 ld_utrace = getenv(LD_ "UTRACE"); 448 449 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 450 ld_elf_hints_path = _PATH_ELF_HINTS; 451 452 if (ld_debug != NULL && *ld_debug != '\0') 453 debug = 1; 454 dbg("%s is initialized, base address = %p", __progname, 455 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 456 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 457 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 458 459 dbg("initializing thread locks"); 460 lockdflt_init(); 461 462 /* 463 * Load the main program, or process its program header if it is 464 * already loaded. 465 */ 466 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */ 467 int fd = aux_info[AT_EXECFD]->a_un.a_val; 468 dbg("loading main program"); 469 obj_main = map_object(fd, argv0, NULL); 470 close(fd); 471 if (obj_main == NULL) 472 rtld_die(); 473 max_stack_flags = obj->stack_flags; 474 } else { /* Main program already loaded. */ 475 const Elf_Phdr *phdr; 476 int phnum; 477 caddr_t entry; 478 479 dbg("processing main program's program header"); 480 assert(aux_info[AT_PHDR] != NULL); 481 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 482 assert(aux_info[AT_PHNUM] != NULL); 483 phnum = aux_info[AT_PHNUM]->a_un.a_val; 484 assert(aux_info[AT_PHENT] != NULL); 485 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 486 assert(aux_info[AT_ENTRY] != NULL); 487 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 488 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL) 489 rtld_die(); 490 } 491 492 if (aux_info[AT_EXECPATH] != 0) { 493 char *kexecpath; 494 char buf[MAXPATHLEN]; 495 496 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 497 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 498 if (kexecpath[0] == '/') 499 obj_main->path = kexecpath; 500 else if (getcwd(buf, sizeof(buf)) == NULL || 501 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 502 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 503 obj_main->path = xstrdup(argv0); 504 else 505 obj_main->path = xstrdup(buf); 506 } else { 507 dbg("No AT_EXECPATH"); 508 obj_main->path = xstrdup(argv0); 509 } 510 dbg("obj_main path %s", obj_main->path); 511 obj_main->mainprog = true; 512 513 if (aux_info[AT_STACKPROT] != NULL && 514 aux_info[AT_STACKPROT]->a_un.a_val != 0) 515 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 516 517#ifndef COMPAT_32BIT 518 /* 519 * Get the actual dynamic linker pathname from the executable if 520 * possible. (It should always be possible.) That ensures that 521 * gdb will find the right dynamic linker even if a non-standard 522 * one is being used. 523 */ 524 if (obj_main->interp != NULL && 525 strcmp(obj_main->interp, obj_rtld.path) != 0) { 526 free(obj_rtld.path); 527 obj_rtld.path = xstrdup(obj_main->interp); 528 __progname = obj_rtld.path; 529 } 530#endif 531 532 digest_dynamic(obj_main, 0); 533 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 534 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 535 obj_main->dynsymcount); 536 537 linkmap_add(obj_main); 538 linkmap_add(&obj_rtld); 539 540 /* Link the main program into the list of objects. */ 541 *obj_tail = obj_main; 542 obj_tail = &obj_main->next; 543 obj_count++; 544 obj_loads++; 545 546 /* Initialize a fake symbol for resolving undefined weak references. */ 547 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 548 sym_zero.st_shndx = SHN_UNDEF; 549 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 550 551 if (!libmap_disable) 552 libmap_disable = (bool)lm_init(libmap_override); 553 554 dbg("loading LD_PRELOAD libraries"); 555 if (load_preload_objects() == -1) 556 rtld_die(); 557 preload_tail = obj_tail; 558 559 dbg("loading needed objects"); 560 if (load_needed_objects(obj_main, 0) == -1) 561 rtld_die(); 562 563 /* Make a list of all objects loaded at startup. */ 564 last_interposer = obj_main; 565 for (obj = obj_list; obj != NULL; obj = obj->next) { 566 if (obj->z_interpose && obj != obj_main) { 567 objlist_put_after(&list_main, last_interposer, obj); 568 last_interposer = obj; 569 } else { 570 objlist_push_tail(&list_main, obj); 571 } 572 obj->refcount++; 573 } 574 575 dbg("checking for required versions"); 576 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 577 rtld_die(); 578 579 if (ld_tracing) { /* We're done */ 580 trace_loaded_objects(obj_main); 581 exit(0); 582 } 583 584 if (getenv(LD_ "DUMP_REL_PRE") != NULL) { 585 dump_relocations(obj_main); 586 exit (0); 587 } 588 589 /* 590 * Processing tls relocations requires having the tls offsets 591 * initialized. Prepare offsets before starting initial 592 * relocation processing. 593 */ 594 dbg("initializing initial thread local storage offsets"); 595 STAILQ_FOREACH(entry, &list_main, link) { 596 /* 597 * Allocate all the initial objects out of the static TLS 598 * block even if they didn't ask for it. 599 */ 600 allocate_tls_offset(entry->obj); 601 } 602 603 if (relocate_objects(obj_main, 604 ld_bind_now != NULL && *ld_bind_now != '\0', 605 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 606 rtld_die(); 607 608 dbg("doing copy relocations"); 609 if (do_copy_relocations(obj_main) == -1) 610 rtld_die(); 611 612 if (getenv(LD_ "DUMP_REL_POST") != NULL) { 613 dump_relocations(obj_main); 614 exit (0); 615 } 616 617 /* 618 * Setup TLS for main thread. This must be done after the 619 * relocations are processed, since tls initialization section 620 * might be the subject for relocations. 621 */ 622 dbg("initializing initial thread local storage"); 623 allocate_initial_tls(obj_list); 624 625 dbg("initializing key program variables"); 626 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 627 set_program_var("environ", env); 628 set_program_var("__elf_aux_vector", aux); 629 630 /* Make a list of init functions to call. */ 631 objlist_init(&initlist); 632 initlist_add_objects(obj_list, preload_tail, &initlist); 633 634 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 635 636 map_stacks_exec(NULL); 637 638 dbg("resolving ifuncs"); 639 if (resolve_objects_ifunc(obj_main, 640 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY, 641 NULL) == -1) 642 rtld_die(); 643 644 if (!obj_main->crt_no_init) { 645 /* 646 * Make sure we don't call the main program's init and fini 647 * functions for binaries linked with old crt1 which calls 648 * _init itself. 649 */ 650 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 651 obj_main->preinit_array = obj_main->init_array = 652 obj_main->fini_array = (Elf_Addr)NULL; 653 } 654 655 wlock_acquire(rtld_bind_lock, &lockstate); 656 if (obj_main->crt_no_init) 657 preinit_main(); 658 objlist_call_init(&initlist, &lockstate); 659 _r_debug_postinit(&obj_main->linkmap); 660 objlist_clear(&initlist); 661 dbg("loading filtees"); 662 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 663 if (ld_loadfltr || obj->z_loadfltr) 664 load_filtees(obj, 0, &lockstate); 665 } 666 lock_release(rtld_bind_lock, &lockstate); 667 668 dbg("transferring control to program entry point = %p", obj_main->entry); 669 670 /* Return the exit procedure and the program entry point. */ 671 *exit_proc = rtld_exit; 672 *objp = obj_main; 673 return (func_ptr_type) obj_main->entry; 674} 675 676void * 677rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 678{ 679 void *ptr; 680 Elf_Addr target; 681 682 ptr = (void *)make_function_pointer(def, obj); 683 target = ((Elf_Addr (*)(void))ptr)(); 684 return ((void *)target); 685} 686 687Elf_Addr 688_rtld_bind(Obj_Entry *obj, Elf_Size reloff) 689{ 690 const Elf_Rel *rel; 691 const Elf_Sym *def; 692 const Obj_Entry *defobj; 693 Elf_Addr *where; 694 Elf_Addr target; 695 RtldLockState lockstate; 696 697 rlock_acquire(rtld_bind_lock, &lockstate); 698 if (sigsetjmp(lockstate.env, 0) != 0) 699 lock_upgrade(rtld_bind_lock, &lockstate); 700 if (obj->pltrel) 701 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 702 else 703 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 704 705 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 706 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL, 707 &lockstate); 708 if (def == NULL) 709 rtld_die(); 710 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 711 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 712 else 713 target = (Elf_Addr)(defobj->relocbase + def->st_value); 714 715 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 716 defobj->strtab + def->st_name, basename(obj->path), 717 (void *)target, basename(defobj->path)); 718 719 /* 720 * Write the new contents for the jmpslot. Note that depending on 721 * architecture, the value which we need to return back to the 722 * lazy binding trampoline may or may not be the target 723 * address. The value returned from reloc_jmpslot() is the value 724 * that the trampoline needs. 725 */ 726 target = reloc_jmpslot(where, target, defobj, obj, rel); 727 lock_release(rtld_bind_lock, &lockstate); 728 return target; 729} 730 731/* 732 * Error reporting function. Use it like printf. If formats the message 733 * into a buffer, and sets things up so that the next call to dlerror() 734 * will return the message. 735 */ 736void 737_rtld_error(const char *fmt, ...) 738{ 739 static char buf[512]; 740 va_list ap; 741 742 va_start(ap, fmt); 743 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 744 error_message = buf; 745 va_end(ap); 746} 747 748/* 749 * Return a dynamically-allocated copy of the current error message, if any. 750 */ 751static char * 752errmsg_save(void) 753{ 754 return error_message == NULL ? NULL : xstrdup(error_message); 755} 756 757/* 758 * Restore the current error message from a copy which was previously saved 759 * by errmsg_save(). The copy is freed. 760 */ 761static void 762errmsg_restore(char *saved_msg) 763{ 764 if (saved_msg == NULL) 765 error_message = NULL; 766 else { 767 _rtld_error("%s", saved_msg); 768 free(saved_msg); 769 } 770} 771 772static const char * 773basename(const char *name) 774{ 775 const char *p = strrchr(name, '/'); 776 return p != NULL ? p + 1 : name; 777} 778 779static struct utsname uts; 780 781static char * 782origin_subst_one(char *real, const char *kw, const char *subst, 783 bool may_free) 784{ 785 char *p, *p1, *res, *resp; 786 int subst_len, kw_len, subst_count, old_len, new_len; 787 788 kw_len = strlen(kw); 789 790 /* 791 * First, count the number of the keyword occurences, to 792 * preallocate the final string. 793 */ 794 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 795 p1 = strstr(p, kw); 796 if (p1 == NULL) 797 break; 798 } 799 800 /* 801 * If the keyword is not found, just return. 802 */ 803 if (subst_count == 0) 804 return (may_free ? real : xstrdup(real)); 805 806 /* 807 * There is indeed something to substitute. Calculate the 808 * length of the resulting string, and allocate it. 809 */ 810 subst_len = strlen(subst); 811 old_len = strlen(real); 812 new_len = old_len + (subst_len - kw_len) * subst_count; 813 res = xmalloc(new_len + 1); 814 815 /* 816 * Now, execute the substitution loop. 817 */ 818 for (p = real, resp = res, *resp = '\0';;) { 819 p1 = strstr(p, kw); 820 if (p1 != NULL) { 821 /* Copy the prefix before keyword. */ 822 memcpy(resp, p, p1 - p); 823 resp += p1 - p; 824 /* Keyword replacement. */ 825 memcpy(resp, subst, subst_len); 826 resp += subst_len; 827 *resp = '\0'; 828 p = p1 + kw_len; 829 } else 830 break; 831 } 832 833 /* Copy to the end of string and finish. */ 834 strcat(resp, p); 835 if (may_free) 836 free(real); 837 return (res); 838} 839 840static char * 841origin_subst(char *real, const char *origin_path) 842{ 843 char *res1, *res2, *res3, *res4; 844 845 if (uts.sysname[0] == '\0') { 846 if (uname(&uts) != 0) { 847 _rtld_error("utsname failed: %d", errno); 848 return (NULL); 849 } 850 } 851 res1 = origin_subst_one(real, "$ORIGIN", origin_path, false); 852 res2 = origin_subst_one(res1, "$OSNAME", uts.sysname, true); 853 res3 = origin_subst_one(res2, "$OSREL", uts.release, true); 854 res4 = origin_subst_one(res3, "$PLATFORM", uts.machine, true); 855 return (res4); 856} 857 858void 859rtld_die(void) 860{ 861 const char *msg = dlerror(); 862 863 if (msg == NULL) 864 msg = "Fatal error"; 865 rtld_fdputstr(STDERR_FILENO, msg); 866 rtld_fdputchar(STDERR_FILENO, '\n'); 867 _exit(1); 868} 869 870/* 871 * Process a shared object's DYNAMIC section, and save the important 872 * information in its Obj_Entry structure. 873 */ 874static void 875digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 876 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 877{ 878 const Elf_Dyn *dynp; 879 Needed_Entry **needed_tail = &obj->needed; 880 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 881 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 882 const Elf_Hashelt *hashtab; 883 const Elf32_Word *hashval; 884 Elf32_Word bkt, nmaskwords; 885 int bloom_size32; 886 int plttype = DT_REL; 887 888 *dyn_rpath = NULL; 889 *dyn_soname = NULL; 890 *dyn_runpath = NULL; 891 892 obj->bind_now = false; 893 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 894 switch (dynp->d_tag) { 895 896 case DT_REL: 897 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 898 break; 899 900 case DT_RELSZ: 901 obj->relsize = dynp->d_un.d_val; 902 break; 903 904 case DT_RELENT: 905 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 906 break; 907 908 case DT_JMPREL: 909 obj->pltrel = (const Elf_Rel *) 910 (obj->relocbase + dynp->d_un.d_ptr); 911 break; 912 913 case DT_PLTRELSZ: 914 obj->pltrelsize = dynp->d_un.d_val; 915 break; 916 917 case DT_RELA: 918 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 919 break; 920 921 case DT_RELASZ: 922 obj->relasize = dynp->d_un.d_val; 923 break; 924 925 case DT_RELAENT: 926 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 927 break; 928 929 case DT_PLTREL: 930 plttype = dynp->d_un.d_val; 931 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 932 break; 933 934 case DT_SYMTAB: 935 obj->symtab = (const Elf_Sym *) 936 (obj->relocbase + dynp->d_un.d_ptr); 937 break; 938 939 case DT_SYMENT: 940 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 941 break; 942 943 case DT_STRTAB: 944 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 945 break; 946 947 case DT_STRSZ: 948 obj->strsize = dynp->d_un.d_val; 949 break; 950 951 case DT_VERNEED: 952 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 953 dynp->d_un.d_val); 954 break; 955 956 case DT_VERNEEDNUM: 957 obj->verneednum = dynp->d_un.d_val; 958 break; 959 960 case DT_VERDEF: 961 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 962 dynp->d_un.d_val); 963 break; 964 965 case DT_VERDEFNUM: 966 obj->verdefnum = dynp->d_un.d_val; 967 break; 968 969 case DT_VERSYM: 970 obj->versyms = (const Elf_Versym *)(obj->relocbase + 971 dynp->d_un.d_val); 972 break; 973 974 case DT_HASH: 975 { 976 hashtab = (const Elf_Hashelt *)(obj->relocbase + 977 dynp->d_un.d_ptr); 978 obj->nbuckets = hashtab[0]; 979 obj->nchains = hashtab[1]; 980 obj->buckets = hashtab + 2; 981 obj->chains = obj->buckets + obj->nbuckets; 982 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 983 obj->buckets != NULL; 984 } 985 break; 986 987 case DT_GNU_HASH: 988 { 989 hashtab = (const Elf_Hashelt *)(obj->relocbase + 990 dynp->d_un.d_ptr); 991 obj->nbuckets_gnu = hashtab[0]; 992 obj->symndx_gnu = hashtab[1]; 993 nmaskwords = hashtab[2]; 994 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 995 obj->maskwords_bm_gnu = nmaskwords - 1; 996 obj->shift2_gnu = hashtab[3]; 997 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4); 998 obj->buckets_gnu = hashtab + 4 + bloom_size32; 999 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1000 obj->symndx_gnu; 1001 /* Number of bitmask words is required to be power of 2 */ 1002 obj->valid_hash_gnu = powerof2(nmaskwords) && 1003 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1004 } 1005 break; 1006 1007 case DT_NEEDED: 1008 if (!obj->rtld) { 1009 Needed_Entry *nep = NEW(Needed_Entry); 1010 nep->name = dynp->d_un.d_val; 1011 nep->obj = NULL; 1012 nep->next = NULL; 1013 1014 *needed_tail = nep; 1015 needed_tail = &nep->next; 1016 } 1017 break; 1018 1019 case DT_FILTER: 1020 if (!obj->rtld) { 1021 Needed_Entry *nep = NEW(Needed_Entry); 1022 nep->name = dynp->d_un.d_val; 1023 nep->obj = NULL; 1024 nep->next = NULL; 1025 1026 *needed_filtees_tail = nep; 1027 needed_filtees_tail = &nep->next; 1028 } 1029 break; 1030 1031 case DT_AUXILIARY: 1032 if (!obj->rtld) { 1033 Needed_Entry *nep = NEW(Needed_Entry); 1034 nep->name = dynp->d_un.d_val; 1035 nep->obj = NULL; 1036 nep->next = NULL; 1037 1038 *needed_aux_filtees_tail = nep; 1039 needed_aux_filtees_tail = &nep->next; 1040 } 1041 break; 1042 1043 case DT_PLTGOT: 1044 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 1045 break; 1046 1047 case DT_TEXTREL: 1048 obj->textrel = true; 1049 break; 1050 1051 case DT_SYMBOLIC: 1052 obj->symbolic = true; 1053 break; 1054 1055 case DT_RPATH: 1056 /* 1057 * We have to wait until later to process this, because we 1058 * might not have gotten the address of the string table yet. 1059 */ 1060 *dyn_rpath = dynp; 1061 break; 1062 1063 case DT_SONAME: 1064 *dyn_soname = dynp; 1065 break; 1066 1067 case DT_RUNPATH: 1068 *dyn_runpath = dynp; 1069 break; 1070 1071 case DT_INIT: 1072 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1073 break; 1074 1075 case DT_PREINIT_ARRAY: 1076 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1077 break; 1078 1079 case DT_PREINIT_ARRAYSZ: 1080 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1081 break; 1082 1083 case DT_INIT_ARRAY: 1084 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1085 break; 1086 1087 case DT_INIT_ARRAYSZ: 1088 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1089 break; 1090 1091 case DT_FINI: 1092 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1093 break; 1094 1095 case DT_FINI_ARRAY: 1096 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1097 break; 1098 1099 case DT_FINI_ARRAYSZ: 1100 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1101 break; 1102 1103 /* 1104 * Don't process DT_DEBUG on MIPS as the dynamic section 1105 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1106 */ 1107 1108#ifndef __mips__ 1109 case DT_DEBUG: 1110 /* XXX - not implemented yet */ 1111 if (!early) 1112 dbg("Filling in DT_DEBUG entry"); 1113 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 1114 break; 1115#endif 1116 1117 case DT_FLAGS: 1118 if ((dynp->d_un.d_val & DF_ORIGIN) && trust) 1119 obj->z_origin = true; 1120 if (dynp->d_un.d_val & DF_SYMBOLIC) 1121 obj->symbolic = true; 1122 if (dynp->d_un.d_val & DF_TEXTREL) 1123 obj->textrel = true; 1124 if (dynp->d_un.d_val & DF_BIND_NOW) 1125 obj->bind_now = true; 1126 /*if (dynp->d_un.d_val & DF_STATIC_TLS) 1127 ;*/ 1128 break; 1129#ifdef __mips__ 1130 case DT_MIPS_LOCAL_GOTNO: 1131 obj->local_gotno = dynp->d_un.d_val; 1132 break; 1133 1134 case DT_MIPS_SYMTABNO: 1135 obj->symtabno = dynp->d_un.d_val; 1136 break; 1137 1138 case DT_MIPS_GOTSYM: 1139 obj->gotsym = dynp->d_un.d_val; 1140 break; 1141 1142 case DT_MIPS_RLD_MAP: 1143 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1144 break; 1145#endif 1146 1147 case DT_FLAGS_1: 1148 if (dynp->d_un.d_val & DF_1_NOOPEN) 1149 obj->z_noopen = true; 1150 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust) 1151 obj->z_origin = true; 1152 if (dynp->d_un.d_val & DF_1_GLOBAL) 1153 obj->z_global = true; 1154 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1155 obj->bind_now = true; 1156 if (dynp->d_un.d_val & DF_1_NODELETE) 1157 obj->z_nodelete = true; 1158 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1159 obj->z_loadfltr = true; 1160 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1161 obj->z_interpose = true; 1162 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1163 obj->z_nodeflib = true; 1164 break; 1165 1166 default: 1167 if (!early) { 1168 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1169 (long)dynp->d_tag); 1170 } 1171 break; 1172 } 1173 } 1174 1175 obj->traced = false; 1176 1177 if (plttype == DT_RELA) { 1178 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1179 obj->pltrel = NULL; 1180 obj->pltrelasize = obj->pltrelsize; 1181 obj->pltrelsize = 0; 1182 } 1183 1184 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1185 if (obj->valid_hash_sysv) 1186 obj->dynsymcount = obj->nchains; 1187 else if (obj->valid_hash_gnu) { 1188 obj->dynsymcount = 0; 1189 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1190 if (obj->buckets_gnu[bkt] == 0) 1191 continue; 1192 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1193 do 1194 obj->dynsymcount++; 1195 while ((*hashval++ & 1u) == 0); 1196 } 1197 obj->dynsymcount += obj->symndx_gnu; 1198 } 1199} 1200 1201static void 1202digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1203 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1204{ 1205 1206 if (obj->z_origin && obj->origin_path == NULL) { 1207 obj->origin_path = xmalloc(PATH_MAX); 1208 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1) 1209 rtld_die(); 1210 } 1211 1212 if (dyn_runpath != NULL) { 1213 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val; 1214 if (obj->z_origin) 1215 obj->runpath = origin_subst(obj->runpath, obj->origin_path); 1216 } 1217 else if (dyn_rpath != NULL) { 1218 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 1219 if (obj->z_origin) 1220 obj->rpath = origin_subst(obj->rpath, obj->origin_path); 1221 } 1222 1223 if (dyn_soname != NULL) 1224 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1225} 1226 1227static void 1228digest_dynamic(Obj_Entry *obj, int early) 1229{ 1230 const Elf_Dyn *dyn_rpath; 1231 const Elf_Dyn *dyn_soname; 1232 const Elf_Dyn *dyn_runpath; 1233 1234 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1235 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath); 1236} 1237 1238/* 1239 * Process a shared object's program header. This is used only for the 1240 * main program, when the kernel has already loaded the main program 1241 * into memory before calling the dynamic linker. It creates and 1242 * returns an Obj_Entry structure. 1243 */ 1244static Obj_Entry * 1245digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1246{ 1247 Obj_Entry *obj; 1248 const Elf_Phdr *phlimit = phdr + phnum; 1249 const Elf_Phdr *ph; 1250 Elf_Addr note_start, note_end; 1251 int nsegs = 0; 1252 1253 obj = obj_new(); 1254 for (ph = phdr; ph < phlimit; ph++) { 1255 if (ph->p_type != PT_PHDR) 1256 continue; 1257 1258 obj->phdr = phdr; 1259 obj->phsize = ph->p_memsz; 1260 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1261 break; 1262 } 1263 1264 obj->stack_flags = PF_X | PF_R | PF_W; 1265 1266 for (ph = phdr; ph < phlimit; ph++) { 1267 switch (ph->p_type) { 1268 1269 case PT_INTERP: 1270 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1271 break; 1272 1273 case PT_LOAD: 1274 if (nsegs == 0) { /* First load segment */ 1275 obj->vaddrbase = trunc_page(ph->p_vaddr); 1276 obj->mapbase = obj->vaddrbase + obj->relocbase; 1277 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1278 obj->vaddrbase; 1279 } else { /* Last load segment */ 1280 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1281 obj->vaddrbase; 1282 } 1283 nsegs++; 1284 break; 1285 1286 case PT_DYNAMIC: 1287 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1288 break; 1289 1290 case PT_TLS: 1291 obj->tlsindex = 1; 1292 obj->tlssize = ph->p_memsz; 1293 obj->tlsalign = ph->p_align; 1294 obj->tlsinitsize = ph->p_filesz; 1295 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1296 break; 1297 1298 case PT_GNU_STACK: 1299 obj->stack_flags = ph->p_flags; 1300 break; 1301 1302 case PT_GNU_RELRO: 1303 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1304 obj->relro_size = round_page(ph->p_memsz); 1305 break; 1306 1307 case PT_NOTE: 1308 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1309 note_end = note_start + ph->p_filesz; 1310 digest_notes(obj, note_start, note_end); 1311 break; 1312 } 1313 } 1314 if (nsegs < 1) { 1315 _rtld_error("%s: too few PT_LOAD segments", path); 1316 return NULL; 1317 } 1318 1319 obj->entry = entry; 1320 return obj; 1321} 1322 1323void 1324digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1325{ 1326 const Elf_Note *note; 1327 const char *note_name; 1328 uintptr_t p; 1329 1330 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1331 note = (const Elf_Note *)((const char *)(note + 1) + 1332 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1333 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1334 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1335 note->n_descsz != sizeof(int32_t)) 1336 continue; 1337 if (note->n_type != ABI_NOTETYPE && 1338 note->n_type != CRT_NOINIT_NOTETYPE) 1339 continue; 1340 note_name = (const char *)(note + 1); 1341 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1342 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1343 continue; 1344 switch (note->n_type) { 1345 case ABI_NOTETYPE: 1346 /* FreeBSD osrel note */ 1347 p = (uintptr_t)(note + 1); 1348 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1349 obj->osrel = *(const int32_t *)(p); 1350 dbg("note osrel %d", obj->osrel); 1351 break; 1352 case CRT_NOINIT_NOTETYPE: 1353 /* FreeBSD 'crt does not call init' note */ 1354 obj->crt_no_init = true; 1355 dbg("note crt_no_init"); 1356 break; 1357 } 1358 } 1359} 1360 1361static Obj_Entry * 1362dlcheck(void *handle) 1363{ 1364 Obj_Entry *obj; 1365 1366 for (obj = obj_list; obj != NULL; obj = obj->next) 1367 if (obj == (Obj_Entry *) handle) 1368 break; 1369 1370 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1371 _rtld_error("Invalid shared object handle %p", handle); 1372 return NULL; 1373 } 1374 return obj; 1375} 1376 1377/* 1378 * If the given object is already in the donelist, return true. Otherwise 1379 * add the object to the list and return false. 1380 */ 1381static bool 1382donelist_check(DoneList *dlp, const Obj_Entry *obj) 1383{ 1384 unsigned int i; 1385 1386 for (i = 0; i < dlp->num_used; i++) 1387 if (dlp->objs[i] == obj) 1388 return true; 1389 /* 1390 * Our donelist allocation should always be sufficient. But if 1391 * our threads locking isn't working properly, more shared objects 1392 * could have been loaded since we allocated the list. That should 1393 * never happen, but we'll handle it properly just in case it does. 1394 */ 1395 if (dlp->num_used < dlp->num_alloc) 1396 dlp->objs[dlp->num_used++] = obj; 1397 return false; 1398} 1399 1400/* 1401 * Hash function for symbol table lookup. Don't even think about changing 1402 * this. It is specified by the System V ABI. 1403 */ 1404unsigned long 1405elf_hash(const char *name) 1406{ 1407 const unsigned char *p = (const unsigned char *) name; 1408 unsigned long h = 0; 1409 unsigned long g; 1410 1411 while (*p != '\0') { 1412 h = (h << 4) + *p++; 1413 if ((g = h & 0xf0000000) != 0) 1414 h ^= g >> 24; 1415 h &= ~g; 1416 } 1417 return h; 1418} 1419 1420/* 1421 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1422 * unsigned in case it's implemented with a wider type. 1423 */ 1424static uint32_t 1425gnu_hash(const char *s) 1426{ 1427 uint32_t h; 1428 unsigned char c; 1429 1430 h = 5381; 1431 for (c = *s; c != '\0'; c = *++s) 1432 h = h * 33 + c; 1433 return (h & 0xffffffff); 1434} 1435 1436/* 1437 * Find the library with the given name, and return its full pathname. 1438 * The returned string is dynamically allocated. Generates an error 1439 * message and returns NULL if the library cannot be found. 1440 * 1441 * If the second argument is non-NULL, then it refers to an already- 1442 * loaded shared object, whose library search path will be searched. 1443 * 1444 * The search order is: 1445 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1446 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1447 * LD_LIBRARY_PATH 1448 * DT_RUNPATH in the referencing file 1449 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1450 * from list) 1451 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1452 * 1453 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1454 */ 1455static char * 1456find_library(const char *xname, const Obj_Entry *refobj) 1457{ 1458 char *pathname; 1459 char *name; 1460 bool nodeflib, objgiven; 1461 1462 objgiven = refobj != NULL; 1463 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */ 1464 if (xname[0] != '/' && !trust) { 1465 _rtld_error("Absolute pathname required for shared object \"%s\"", 1466 xname); 1467 return NULL; 1468 } 1469 if (objgiven && refobj->z_origin) { 1470 return (origin_subst(__DECONST(char *, xname), 1471 refobj->origin_path)); 1472 } else { 1473 return (xstrdup(xname)); 1474 } 1475 } 1476 1477 if (libmap_disable || !objgiven || 1478 (name = lm_find(refobj->path, xname)) == NULL) 1479 name = (char *)xname; 1480 1481 dbg(" Searching for \"%s\"", name); 1482 1483 /* 1484 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1485 * back to pre-conforming behaviour if user requested so with 1486 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1487 * nodeflib. 1488 */ 1489 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1490 if ((pathname = search_library_path(name, ld_library_path)) != NULL || 1491 (refobj != NULL && 1492 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1493 (pathname = search_library_path(name, gethints(false))) != NULL || 1494 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL) 1495 return (pathname); 1496 } else { 1497 nodeflib = objgiven ? refobj->z_nodeflib : false; 1498 if ((objgiven && 1499 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1500 (objgiven && refobj->runpath == NULL && refobj != obj_main && 1501 (pathname = search_library_path(name, obj_main->rpath)) != NULL) || 1502 (pathname = search_library_path(name, ld_library_path)) != NULL || 1503 (objgiven && 1504 (pathname = search_library_path(name, refobj->runpath)) != NULL) || 1505 (pathname = search_library_path(name, gethints(nodeflib))) != NULL || 1506 (objgiven && !nodeflib && 1507 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)) 1508 return (pathname); 1509 } 1510 1511 if (objgiven && refobj->path != NULL) { 1512 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 1513 name, basename(refobj->path)); 1514 } else { 1515 _rtld_error("Shared object \"%s\" not found", name); 1516 } 1517 return NULL; 1518} 1519 1520/* 1521 * Given a symbol number in a referencing object, find the corresponding 1522 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1523 * no definition was found. Returns a pointer to the Obj_Entry of the 1524 * defining object via the reference parameter DEFOBJ_OUT. 1525 */ 1526const Elf_Sym * 1527find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1528 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1529 RtldLockState *lockstate) 1530{ 1531 const Elf_Sym *ref; 1532 const Elf_Sym *def; 1533 const Obj_Entry *defobj; 1534 SymLook req; 1535 const char *name; 1536 int res; 1537 1538 /* 1539 * If we have already found this symbol, get the information from 1540 * the cache. 1541 */ 1542 if (symnum >= refobj->dynsymcount) 1543 return NULL; /* Bad object */ 1544 if (cache != NULL && cache[symnum].sym != NULL) { 1545 *defobj_out = cache[symnum].obj; 1546 return cache[symnum].sym; 1547 } 1548 1549 ref = refobj->symtab + symnum; 1550 name = refobj->strtab + ref->st_name; 1551 def = NULL; 1552 defobj = NULL; 1553 1554 /* 1555 * We don't have to do a full scale lookup if the symbol is local. 1556 * We know it will bind to the instance in this load module; to 1557 * which we already have a pointer (ie ref). By not doing a lookup, 1558 * we not only improve performance, but it also avoids unresolvable 1559 * symbols when local symbols are not in the hash table. This has 1560 * been seen with the ia64 toolchain. 1561 */ 1562 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1563 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1564 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1565 symnum); 1566 } 1567 symlook_init(&req, name); 1568 req.flags = flags; 1569 req.ventry = fetch_ventry(refobj, symnum); 1570 req.lockstate = lockstate; 1571 res = symlook_default(&req, refobj); 1572 if (res == 0) { 1573 def = req.sym_out; 1574 defobj = req.defobj_out; 1575 } 1576 } else { 1577 def = ref; 1578 defobj = refobj; 1579 } 1580 1581 /* 1582 * If we found no definition and the reference is weak, treat the 1583 * symbol as having the value zero. 1584 */ 1585 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1586 def = &sym_zero; 1587 defobj = obj_main; 1588 } 1589 1590 if (def != NULL) { 1591 *defobj_out = defobj; 1592 /* Record the information in the cache to avoid subsequent lookups. */ 1593 if (cache != NULL) { 1594 cache[symnum].sym = def; 1595 cache[symnum].obj = defobj; 1596 } 1597 } else { 1598 if (refobj != &obj_rtld) 1599 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name); 1600 } 1601 return def; 1602} 1603 1604/* 1605 * Return the search path from the ldconfig hints file, reading it if 1606 * necessary. If nostdlib is true, then the default search paths are 1607 * not added to result. 1608 * 1609 * Returns NULL if there are problems with the hints file, 1610 * or if the search path there is empty. 1611 */ 1612static const char * 1613gethints(bool nostdlib) 1614{ 1615 static char *hints, *filtered_path; 1616 struct elfhints_hdr hdr; 1617 struct fill_search_info_args sargs, hargs; 1618 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1619 struct dl_serpath *SLPpath, *hintpath; 1620 char *p; 1621 unsigned int SLPndx, hintndx, fndx, fcount; 1622 int fd; 1623 size_t flen; 1624 bool skip; 1625 1626 /* First call, read the hints file */ 1627 if (hints == NULL) { 1628 /* Keep from trying again in case the hints file is bad. */ 1629 hints = ""; 1630 1631 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1632 return (NULL); 1633 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1634 hdr.magic != ELFHINTS_MAGIC || 1635 hdr.version != 1) { 1636 close(fd); 1637 return (NULL); 1638 } 1639 p = xmalloc(hdr.dirlistlen + 1); 1640 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1641 read(fd, p, hdr.dirlistlen + 1) != 1642 (ssize_t)hdr.dirlistlen + 1) { 1643 free(p); 1644 close(fd); 1645 return (NULL); 1646 } 1647 hints = p; 1648 close(fd); 1649 } 1650 1651 /* 1652 * If caller agreed to receive list which includes the default 1653 * paths, we are done. Otherwise, if we still did not 1654 * calculated filtered result, do it now. 1655 */ 1656 if (!nostdlib) 1657 return (hints[0] != '\0' ? hints : NULL); 1658 if (filtered_path != NULL) 1659 goto filt_ret; 1660 1661 /* 1662 * Obtain the list of all configured search paths, and the 1663 * list of the default paths. 1664 * 1665 * First estimate the size of the results. 1666 */ 1667 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1668 smeta.dls_cnt = 0; 1669 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1670 hmeta.dls_cnt = 0; 1671 1672 sargs.request = RTLD_DI_SERINFOSIZE; 1673 sargs.serinfo = &smeta; 1674 hargs.request = RTLD_DI_SERINFOSIZE; 1675 hargs.serinfo = &hmeta; 1676 1677 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1678 path_enumerate(p, fill_search_info, &hargs); 1679 1680 SLPinfo = xmalloc(smeta.dls_size); 1681 hintinfo = xmalloc(hmeta.dls_size); 1682 1683 /* 1684 * Next fetch both sets of paths. 1685 */ 1686 sargs.request = RTLD_DI_SERINFO; 1687 sargs.serinfo = SLPinfo; 1688 sargs.serpath = &SLPinfo->dls_serpath[0]; 1689 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1690 1691 hargs.request = RTLD_DI_SERINFO; 1692 hargs.serinfo = hintinfo; 1693 hargs.serpath = &hintinfo->dls_serpath[0]; 1694 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1695 1696 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1697 path_enumerate(p, fill_search_info, &hargs); 1698 1699 /* 1700 * Now calculate the difference between two sets, by excluding 1701 * standard paths from the full set. 1702 */ 1703 fndx = 0; 1704 fcount = 0; 1705 filtered_path = xmalloc(hdr.dirlistlen + 1); 1706 hintpath = &hintinfo->dls_serpath[0]; 1707 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1708 skip = false; 1709 SLPpath = &SLPinfo->dls_serpath[0]; 1710 /* 1711 * Check each standard path against current. 1712 */ 1713 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1714 /* matched, skip the path */ 1715 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1716 skip = true; 1717 break; 1718 } 1719 } 1720 if (skip) 1721 continue; 1722 /* 1723 * Not matched against any standard path, add the path 1724 * to result. Separate consequtive paths with ':'. 1725 */ 1726 if (fcount > 0) { 1727 filtered_path[fndx] = ':'; 1728 fndx++; 1729 } 1730 fcount++; 1731 flen = strlen(hintpath->dls_name); 1732 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1733 fndx += flen; 1734 } 1735 filtered_path[fndx] = '\0'; 1736 1737 free(SLPinfo); 1738 free(hintinfo); 1739 1740filt_ret: 1741 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1742} 1743 1744static void 1745init_dag(Obj_Entry *root) 1746{ 1747 const Needed_Entry *needed; 1748 const Objlist_Entry *elm; 1749 DoneList donelist; 1750 1751 if (root->dag_inited) 1752 return; 1753 donelist_init(&donelist); 1754 1755 /* Root object belongs to own DAG. */ 1756 objlist_push_tail(&root->dldags, root); 1757 objlist_push_tail(&root->dagmembers, root); 1758 donelist_check(&donelist, root); 1759 1760 /* 1761 * Add dependencies of root object to DAG in breadth order 1762 * by exploiting the fact that each new object get added 1763 * to the tail of the dagmembers list. 1764 */ 1765 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1766 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1767 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1768 continue; 1769 objlist_push_tail(&needed->obj->dldags, root); 1770 objlist_push_tail(&root->dagmembers, needed->obj); 1771 } 1772 } 1773 root->dag_inited = true; 1774} 1775 1776static void 1777process_z(Obj_Entry *root) 1778{ 1779 const Objlist_Entry *elm; 1780 Obj_Entry *obj; 1781 1782 /* 1783 * Walk over object DAG and process every dependent object 1784 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 1785 * to grow their own DAG. 1786 * 1787 * For DF_1_GLOBAL, DAG is required for symbol lookups in 1788 * symlook_global() to work. 1789 * 1790 * For DF_1_NODELETE, the DAG should have its reference upped. 1791 */ 1792 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1793 obj = elm->obj; 1794 if (obj == NULL) 1795 continue; 1796 if (obj->z_nodelete && !obj->ref_nodel) { 1797 dbg("obj %s -z nodelete", obj->path); 1798 init_dag(obj); 1799 ref_dag(obj); 1800 obj->ref_nodel = true; 1801 } 1802 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 1803 dbg("obj %s -z global", obj->path); 1804 objlist_push_tail(&list_global, obj); 1805 init_dag(obj); 1806 } 1807 } 1808} 1809/* 1810 * Initialize the dynamic linker. The argument is the address at which 1811 * the dynamic linker has been mapped into memory. The primary task of 1812 * this function is to relocate the dynamic linker. 1813 */ 1814static void 1815init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 1816{ 1817 Obj_Entry objtmp; /* Temporary rtld object */ 1818 const Elf_Dyn *dyn_rpath; 1819 const Elf_Dyn *dyn_soname; 1820 const Elf_Dyn *dyn_runpath; 1821 1822#ifdef RTLD_INIT_PAGESIZES_EARLY 1823 /* The page size is required by the dynamic memory allocator. */ 1824 init_pagesizes(aux_info); 1825#endif 1826 1827 /* 1828 * Conjure up an Obj_Entry structure for the dynamic linker. 1829 * 1830 * The "path" member can't be initialized yet because string constants 1831 * cannot yet be accessed. Below we will set it correctly. 1832 */ 1833 memset(&objtmp, 0, sizeof(objtmp)); 1834 objtmp.path = NULL; 1835 objtmp.rtld = true; 1836 objtmp.mapbase = mapbase; 1837#ifdef PIC 1838 objtmp.relocbase = mapbase; 1839#endif 1840 if (RTLD_IS_DYNAMIC()) { 1841 objtmp.dynamic = rtld_dynamic(&objtmp); 1842 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 1843 assert(objtmp.needed == NULL); 1844#if !defined(__mips__) 1845 /* MIPS has a bogus DT_TEXTREL. */ 1846 assert(!objtmp.textrel); 1847#endif 1848 1849 /* 1850 * Temporarily put the dynamic linker entry into the object list, so 1851 * that symbols can be found. 1852 */ 1853 1854 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 1855 } 1856 1857 /* Initialize the object list. */ 1858 obj_tail = &obj_list; 1859 1860 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1861 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1862 1863#ifndef RTLD_INIT_PAGESIZES_EARLY 1864 /* The page size is required by the dynamic memory allocator. */ 1865 init_pagesizes(aux_info); 1866#endif 1867 1868 if (aux_info[AT_OSRELDATE] != NULL) 1869 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 1870 1871 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 1872 1873 /* Replace the path with a dynamically allocated copy. */ 1874 obj_rtld.path = xstrdup(PATH_RTLD); 1875 1876 r_debug.r_brk = r_debug_state; 1877 r_debug.r_state = RT_CONSISTENT; 1878} 1879 1880/* 1881 * Retrieve the array of supported page sizes. The kernel provides the page 1882 * sizes in increasing order. 1883 */ 1884static void 1885init_pagesizes(Elf_Auxinfo **aux_info) 1886{ 1887 static size_t psa[MAXPAGESIZES]; 1888 int mib[2]; 1889 size_t len, size; 1890 1891 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 1892 NULL) { 1893 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 1894 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 1895 } else { 1896 len = 2; 1897 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 1898 size = sizeof(psa); 1899 else { 1900 /* As a fallback, retrieve the base page size. */ 1901 size = sizeof(psa[0]); 1902 if (aux_info[AT_PAGESZ] != NULL) { 1903 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 1904 goto psa_filled; 1905 } else { 1906 mib[0] = CTL_HW; 1907 mib[1] = HW_PAGESIZE; 1908 len = 2; 1909 } 1910 } 1911 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 1912 _rtld_error("sysctl for hw.pagesize(s) failed"); 1913 rtld_die(); 1914 } 1915psa_filled: 1916 pagesizes = psa; 1917 } 1918 npagesizes = size / sizeof(pagesizes[0]); 1919 /* Discard any invalid entries at the end of the array. */ 1920 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 1921 npagesizes--; 1922} 1923 1924/* 1925 * Add the init functions from a needed object list (and its recursive 1926 * needed objects) to "list". This is not used directly; it is a helper 1927 * function for initlist_add_objects(). The write lock must be held 1928 * when this function is called. 1929 */ 1930static void 1931initlist_add_neededs(Needed_Entry *needed, Objlist *list) 1932{ 1933 /* Recursively process the successor needed objects. */ 1934 if (needed->next != NULL) 1935 initlist_add_neededs(needed->next, list); 1936 1937 /* Process the current needed object. */ 1938 if (needed->obj != NULL) 1939 initlist_add_objects(needed->obj, &needed->obj->next, list); 1940} 1941 1942/* 1943 * Scan all of the DAGs rooted in the range of objects from "obj" to 1944 * "tail" and add their init functions to "list". This recurses over 1945 * the DAGs and ensure the proper init ordering such that each object's 1946 * needed libraries are initialized before the object itself. At the 1947 * same time, this function adds the objects to the global finalization 1948 * list "list_fini" in the opposite order. The write lock must be 1949 * held when this function is called. 1950 */ 1951static void 1952initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list) 1953{ 1954 1955 if (obj->init_scanned || obj->init_done) 1956 return; 1957 obj->init_scanned = true; 1958 1959 /* Recursively process the successor objects. */ 1960 if (&obj->next != tail) 1961 initlist_add_objects(obj->next, tail, list); 1962 1963 /* Recursively process the needed objects. */ 1964 if (obj->needed != NULL) 1965 initlist_add_neededs(obj->needed, list); 1966 if (obj->needed_filtees != NULL) 1967 initlist_add_neededs(obj->needed_filtees, list); 1968 if (obj->needed_aux_filtees != NULL) 1969 initlist_add_neededs(obj->needed_aux_filtees, list); 1970 1971 /* Add the object to the init list. */ 1972 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL || 1973 obj->init_array != (Elf_Addr)NULL) 1974 objlist_push_tail(list, obj); 1975 1976 /* Add the object to the global fini list in the reverse order. */ 1977 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 1978 && !obj->on_fini_list) { 1979 objlist_push_head(&list_fini, obj); 1980 obj->on_fini_list = true; 1981 } 1982} 1983 1984#ifndef FPTR_TARGET 1985#define FPTR_TARGET(f) ((Elf_Addr) (f)) 1986#endif 1987 1988static void 1989free_needed_filtees(Needed_Entry *n) 1990{ 1991 Needed_Entry *needed, *needed1; 1992 1993 for (needed = n; needed != NULL; needed = needed->next) { 1994 if (needed->obj != NULL) { 1995 dlclose(needed->obj); 1996 needed->obj = NULL; 1997 } 1998 } 1999 for (needed = n; needed != NULL; needed = needed1) { 2000 needed1 = needed->next; 2001 free(needed); 2002 } 2003} 2004 2005static void 2006unload_filtees(Obj_Entry *obj) 2007{ 2008 2009 free_needed_filtees(obj->needed_filtees); 2010 obj->needed_filtees = NULL; 2011 free_needed_filtees(obj->needed_aux_filtees); 2012 obj->needed_aux_filtees = NULL; 2013 obj->filtees_loaded = false; 2014} 2015 2016static void 2017load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2018 RtldLockState *lockstate) 2019{ 2020 2021 for (; needed != NULL; needed = needed->next) { 2022 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2023 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2024 RTLD_LOCAL, lockstate); 2025 } 2026} 2027 2028static void 2029load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2030{ 2031 2032 lock_restart_for_upgrade(lockstate); 2033 if (!obj->filtees_loaded) { 2034 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2035 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2036 obj->filtees_loaded = true; 2037 } 2038} 2039 2040static int 2041process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2042{ 2043 Obj_Entry *obj1; 2044 2045 for (; needed != NULL; needed = needed->next) { 2046 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2047 flags & ~RTLD_LO_NOLOAD); 2048 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2049 return (-1); 2050 } 2051 return (0); 2052} 2053 2054/* 2055 * Given a shared object, traverse its list of needed objects, and load 2056 * each of them. Returns 0 on success. Generates an error message and 2057 * returns -1 on failure. 2058 */ 2059static int 2060load_needed_objects(Obj_Entry *first, int flags) 2061{ 2062 Obj_Entry *obj; 2063 2064 for (obj = first; obj != NULL; obj = obj->next) { 2065 if (process_needed(obj, obj->needed, flags) == -1) 2066 return (-1); 2067 } 2068 return (0); 2069} 2070 2071static int 2072load_preload_objects(void) 2073{ 2074 char *p = ld_preload; 2075 Obj_Entry *obj; 2076 static const char delim[] = " \t:;"; 2077 2078 if (p == NULL) 2079 return 0; 2080 2081 p += strspn(p, delim); 2082 while (*p != '\0') { 2083 size_t len = strcspn(p, delim); 2084 char savech; 2085 2086 savech = p[len]; 2087 p[len] = '\0'; 2088 obj = load_object(p, -1, NULL, 0); 2089 if (obj == NULL) 2090 return -1; /* XXX - cleanup */ 2091 obj->z_interpose = true; 2092 p[len] = savech; 2093 p += len; 2094 p += strspn(p, delim); 2095 } 2096 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2097 return 0; 2098} 2099 2100static const char * 2101printable_path(const char *path) 2102{ 2103 2104 return (path == NULL ? "<unknown>" : path); 2105} 2106 2107/* 2108 * Load a shared object into memory, if it is not already loaded. The 2109 * object may be specified by name or by user-supplied file descriptor 2110 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2111 * duplicate is. 2112 * 2113 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2114 * on failure. 2115 */ 2116static Obj_Entry * 2117load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2118{ 2119 Obj_Entry *obj; 2120 int fd; 2121 struct stat sb; 2122 char *path; 2123 2124 if (name != NULL) { 2125 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 2126 if (object_match_name(obj, name)) 2127 return (obj); 2128 } 2129 2130 path = find_library(name, refobj); 2131 if (path == NULL) 2132 return (NULL); 2133 } else 2134 path = NULL; 2135 2136 /* 2137 * If we didn't find a match by pathname, or the name is not 2138 * supplied, open the file and check again by device and inode. 2139 * This avoids false mismatches caused by multiple links or ".." 2140 * in pathnames. 2141 * 2142 * To avoid a race, we open the file and use fstat() rather than 2143 * using stat(). 2144 */ 2145 fd = -1; 2146 if (fd_u == -1) { 2147 if ((fd = open(path, O_RDONLY | O_CLOEXEC)) == -1) { 2148 _rtld_error("Cannot open \"%s\"", path); 2149 free(path); 2150 return (NULL); 2151 } 2152 } else { 2153 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2154 if (fd == -1) { 2155 _rtld_error("Cannot dup fd"); 2156 free(path); 2157 return (NULL); 2158 } 2159 } 2160 if (fstat(fd, &sb) == -1) { 2161 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2162 close(fd); 2163 free(path); 2164 return NULL; 2165 } 2166 for (obj = obj_list->next; obj != NULL; obj = obj->next) 2167 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2168 break; 2169 if (obj != NULL && name != NULL) { 2170 object_add_name(obj, name); 2171 free(path); 2172 close(fd); 2173 return obj; 2174 } 2175 if (flags & RTLD_LO_NOLOAD) { 2176 free(path); 2177 close(fd); 2178 return (NULL); 2179 } 2180 2181 /* First use of this object, so we must map it in */ 2182 obj = do_load_object(fd, name, path, &sb, flags); 2183 if (obj == NULL) 2184 free(path); 2185 close(fd); 2186 2187 return obj; 2188} 2189 2190static Obj_Entry * 2191do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2192 int flags) 2193{ 2194 Obj_Entry *obj; 2195 struct statfs fs; 2196 2197 /* 2198 * but first, make sure that environment variables haven't been 2199 * used to circumvent the noexec flag on a filesystem. 2200 */ 2201 if (dangerous_ld_env) { 2202 if (fstatfs(fd, &fs) != 0) { 2203 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2204 return NULL; 2205 } 2206 if (fs.f_flags & MNT_NOEXEC) { 2207 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 2208 return NULL; 2209 } 2210 } 2211 dbg("loading \"%s\"", printable_path(path)); 2212 obj = map_object(fd, printable_path(path), sbp); 2213 if (obj == NULL) 2214 return NULL; 2215 2216 /* 2217 * If DT_SONAME is present in the object, digest_dynamic2 already 2218 * added it to the object names. 2219 */ 2220 if (name != NULL) 2221 object_add_name(obj, name); 2222 obj->path = path; 2223 digest_dynamic(obj, 0); 2224 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2225 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2226 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2227 RTLD_LO_DLOPEN) { 2228 dbg("refusing to load non-loadable \"%s\"", obj->path); 2229 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2230 munmap(obj->mapbase, obj->mapsize); 2231 obj_free(obj); 2232 return (NULL); 2233 } 2234 2235 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2236 *obj_tail = obj; 2237 obj_tail = &obj->next; 2238 obj_count++; 2239 obj_loads++; 2240 linkmap_add(obj); /* for GDB & dlinfo() */ 2241 max_stack_flags |= obj->stack_flags; 2242 2243 dbg(" %p .. %p: %s", obj->mapbase, 2244 obj->mapbase + obj->mapsize - 1, obj->path); 2245 if (obj->textrel) 2246 dbg(" WARNING: %s has impure text", obj->path); 2247 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2248 obj->path); 2249 2250 return obj; 2251} 2252 2253static Obj_Entry * 2254obj_from_addr(const void *addr) 2255{ 2256 Obj_Entry *obj; 2257 2258 for (obj = obj_list; obj != NULL; obj = obj->next) { 2259 if (addr < (void *) obj->mapbase) 2260 continue; 2261 if (addr < (void *) (obj->mapbase + obj->mapsize)) 2262 return obj; 2263 } 2264 return NULL; 2265} 2266 2267static void 2268preinit_main(void) 2269{ 2270 Elf_Addr *preinit_addr; 2271 int index; 2272 2273 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2274 if (preinit_addr == NULL) 2275 return; 2276 2277 for (index = 0; index < obj_main->preinit_array_num; index++) { 2278 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2279 dbg("calling preinit function for %s at %p", obj_main->path, 2280 (void *)preinit_addr[index]); 2281 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2282 0, 0, obj_main->path); 2283 call_init_pointer(obj_main, preinit_addr[index]); 2284 } 2285 } 2286} 2287 2288/* 2289 * Call the finalization functions for each of the objects in "list" 2290 * belonging to the DAG of "root" and referenced once. If NULL "root" 2291 * is specified, every finalization function will be called regardless 2292 * of the reference count and the list elements won't be freed. All of 2293 * the objects are expected to have non-NULL fini functions. 2294 */ 2295static void 2296objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2297{ 2298 Objlist_Entry *elm; 2299 char *saved_msg; 2300 Elf_Addr *fini_addr; 2301 int index; 2302 2303 assert(root == NULL || root->refcount == 1); 2304 2305 /* 2306 * Preserve the current error message since a fini function might 2307 * call into the dynamic linker and overwrite it. 2308 */ 2309 saved_msg = errmsg_save(); 2310 do { 2311 STAILQ_FOREACH(elm, list, link) { 2312 if (root != NULL && (elm->obj->refcount != 1 || 2313 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2314 continue; 2315 /* Remove object from fini list to prevent recursive invocation. */ 2316 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2317 /* 2318 * XXX: If a dlopen() call references an object while the 2319 * fini function is in progress, we might end up trying to 2320 * unload the referenced object in dlclose() or the object 2321 * won't be unloaded although its fini function has been 2322 * called. 2323 */ 2324 lock_release(rtld_bind_lock, lockstate); 2325 2326 /* 2327 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2328 * When this happens, DT_FINI_ARRAY is processed first. 2329 */ 2330 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2331 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2332 for (index = elm->obj->fini_array_num - 1; index >= 0; 2333 index--) { 2334 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2335 dbg("calling fini function for %s at %p", 2336 elm->obj->path, (void *)fini_addr[index]); 2337 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2338 (void *)fini_addr[index], 0, 0, elm->obj->path); 2339 call_initfini_pointer(elm->obj, fini_addr[index]); 2340 } 2341 } 2342 } 2343 if (elm->obj->fini != (Elf_Addr)NULL) { 2344 dbg("calling fini function for %s at %p", elm->obj->path, 2345 (void *)elm->obj->fini); 2346 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2347 0, 0, elm->obj->path); 2348 call_initfini_pointer(elm->obj, elm->obj->fini); 2349 } 2350 wlock_acquire(rtld_bind_lock, lockstate); 2351 /* No need to free anything if process is going down. */ 2352 if (root != NULL) 2353 free(elm); 2354 /* 2355 * We must restart the list traversal after every fini call 2356 * because a dlclose() call from the fini function or from 2357 * another thread might have modified the reference counts. 2358 */ 2359 break; 2360 } 2361 } while (elm != NULL); 2362 errmsg_restore(saved_msg); 2363} 2364 2365/* 2366 * Call the initialization functions for each of the objects in 2367 * "list". All of the objects are expected to have non-NULL init 2368 * functions. 2369 */ 2370static void 2371objlist_call_init(Objlist *list, RtldLockState *lockstate) 2372{ 2373 Objlist_Entry *elm; 2374 Obj_Entry *obj; 2375 char *saved_msg; 2376 Elf_Addr *init_addr; 2377 int index; 2378 2379 /* 2380 * Clean init_scanned flag so that objects can be rechecked and 2381 * possibly initialized earlier if any of vectors called below 2382 * cause the change by using dlopen. 2383 */ 2384 for (obj = obj_list; obj != NULL; obj = obj->next) 2385 obj->init_scanned = false; 2386 2387 /* 2388 * Preserve the current error message since an init function might 2389 * call into the dynamic linker and overwrite it. 2390 */ 2391 saved_msg = errmsg_save(); 2392 STAILQ_FOREACH(elm, list, link) { 2393 if (elm->obj->init_done) /* Initialized early. */ 2394 continue; 2395 /* 2396 * Race: other thread might try to use this object before current 2397 * one completes the initilization. Not much can be done here 2398 * without better locking. 2399 */ 2400 elm->obj->init_done = true; 2401 lock_release(rtld_bind_lock, lockstate); 2402 2403 /* 2404 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2405 * When this happens, DT_INIT is processed first. 2406 */ 2407 if (elm->obj->init != (Elf_Addr)NULL) { 2408 dbg("calling init function for %s at %p", elm->obj->path, 2409 (void *)elm->obj->init); 2410 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2411 0, 0, elm->obj->path); 2412 call_initfini_pointer(elm->obj, elm->obj->init); 2413 } 2414 init_addr = (Elf_Addr *)elm->obj->init_array; 2415 if (init_addr != NULL) { 2416 for (index = 0; index < elm->obj->init_array_num; index++) { 2417 if (init_addr[index] != 0 && init_addr[index] != 1) { 2418 dbg("calling init function for %s at %p", elm->obj->path, 2419 (void *)init_addr[index]); 2420 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2421 (void *)init_addr[index], 0, 0, elm->obj->path); 2422 call_init_pointer(elm->obj, init_addr[index]); 2423 } 2424 } 2425 } 2426 wlock_acquire(rtld_bind_lock, lockstate); 2427 } 2428 errmsg_restore(saved_msg); 2429} 2430 2431static void 2432objlist_clear(Objlist *list) 2433{ 2434 Objlist_Entry *elm; 2435 2436 while (!STAILQ_EMPTY(list)) { 2437 elm = STAILQ_FIRST(list); 2438 STAILQ_REMOVE_HEAD(list, link); 2439 free(elm); 2440 } 2441} 2442 2443static Objlist_Entry * 2444objlist_find(Objlist *list, const Obj_Entry *obj) 2445{ 2446 Objlist_Entry *elm; 2447 2448 STAILQ_FOREACH(elm, list, link) 2449 if (elm->obj == obj) 2450 return elm; 2451 return NULL; 2452} 2453 2454static void 2455objlist_init(Objlist *list) 2456{ 2457 STAILQ_INIT(list); 2458} 2459 2460static void 2461objlist_push_head(Objlist *list, Obj_Entry *obj) 2462{ 2463 Objlist_Entry *elm; 2464 2465 elm = NEW(Objlist_Entry); 2466 elm->obj = obj; 2467 STAILQ_INSERT_HEAD(list, elm, link); 2468} 2469 2470static void 2471objlist_push_tail(Objlist *list, Obj_Entry *obj) 2472{ 2473 Objlist_Entry *elm; 2474 2475 elm = NEW(Objlist_Entry); 2476 elm->obj = obj; 2477 STAILQ_INSERT_TAIL(list, elm, link); 2478} 2479 2480static void 2481objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2482{ 2483 Objlist_Entry *elm, *listelm; 2484 2485 STAILQ_FOREACH(listelm, list, link) { 2486 if (listelm->obj == listobj) 2487 break; 2488 } 2489 elm = NEW(Objlist_Entry); 2490 elm->obj = obj; 2491 if (listelm != NULL) 2492 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2493 else 2494 STAILQ_INSERT_TAIL(list, elm, link); 2495} 2496 2497static void 2498objlist_remove(Objlist *list, Obj_Entry *obj) 2499{ 2500 Objlist_Entry *elm; 2501 2502 if ((elm = objlist_find(list, obj)) != NULL) { 2503 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2504 free(elm); 2505 } 2506} 2507 2508/* 2509 * Relocate dag rooted in the specified object. 2510 * Returns 0 on success, or -1 on failure. 2511 */ 2512 2513static int 2514relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2515 int flags, RtldLockState *lockstate) 2516{ 2517 Objlist_Entry *elm; 2518 int error; 2519 2520 error = 0; 2521 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2522 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2523 lockstate); 2524 if (error == -1) 2525 break; 2526 } 2527 return (error); 2528} 2529 2530/* 2531 * Relocate single object. 2532 * Returns 0 on success, or -1 on failure. 2533 */ 2534static int 2535relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2536 int flags, RtldLockState *lockstate) 2537{ 2538 2539 if (obj->relocated) 2540 return (0); 2541 obj->relocated = true; 2542 if (obj != rtldobj) 2543 dbg("relocating \"%s\"", obj->path); 2544 2545 if (obj->symtab == NULL || obj->strtab == NULL || 2546 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2547 _rtld_error("%s: Shared object has no run-time symbol table", 2548 obj->path); 2549 return (-1); 2550 } 2551 2552 if (obj->textrel) { 2553 /* There are relocations to the write-protected text segment. */ 2554 if (mprotect(obj->mapbase, obj->textsize, 2555 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) { 2556 _rtld_error("%s: Cannot write-enable text segment: %s", 2557 obj->path, rtld_strerror(errno)); 2558 return (-1); 2559 } 2560 } 2561 2562 /* Process the non-PLT non-IFUNC relocations. */ 2563 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2564 return (-1); 2565 2566 if (obj->textrel) { /* Re-protected the text segment. */ 2567 if (mprotect(obj->mapbase, obj->textsize, 2568 PROT_READ|PROT_EXEC) == -1) { 2569 _rtld_error("%s: Cannot write-protect text segment: %s", 2570 obj->path, rtld_strerror(errno)); 2571 return (-1); 2572 } 2573 } 2574 2575 /* Set the special PLT or GOT entries. */ 2576 init_pltgot(obj); 2577 2578 /* Process the PLT relocations. */ 2579 if (reloc_plt(obj) == -1) 2580 return (-1); 2581 /* Relocate the jump slots if we are doing immediate binding. */ 2582 if (obj->bind_now || bind_now) 2583 if (reloc_jmpslots(obj, flags, lockstate) == -1) 2584 return (-1); 2585 2586 /* 2587 * Process the non-PLT IFUNC relocations. The relocations are 2588 * processed in two phases, because IFUNC resolvers may 2589 * reference other symbols, which must be readily processed 2590 * before resolvers are called. 2591 */ 2592 if (obj->non_plt_gnu_ifunc && 2593 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate)) 2594 return (-1); 2595 2596 if (obj->relro_size > 0) { 2597 if (mprotect(obj->relro_page, obj->relro_size, 2598 PROT_READ) == -1) { 2599 _rtld_error("%s: Cannot enforce relro protection: %s", 2600 obj->path, rtld_strerror(errno)); 2601 return (-1); 2602 } 2603 } 2604 2605 /* 2606 * Set up the magic number and version in the Obj_Entry. These 2607 * were checked in the crt1.o from the original ElfKit, so we 2608 * set them for backward compatibility. 2609 */ 2610 obj->magic = RTLD_MAGIC; 2611 obj->version = RTLD_VERSION; 2612 2613 return (0); 2614} 2615 2616/* 2617 * Relocate newly-loaded shared objects. The argument is a pointer to 2618 * the Obj_Entry for the first such object. All objects from the first 2619 * to the end of the list of objects are relocated. Returns 0 on success, 2620 * or -1 on failure. 2621 */ 2622static int 2623relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2624 int flags, RtldLockState *lockstate) 2625{ 2626 Obj_Entry *obj; 2627 int error; 2628 2629 for (error = 0, obj = first; obj != NULL; obj = obj->next) { 2630 error = relocate_object(obj, bind_now, rtldobj, flags, 2631 lockstate); 2632 if (error == -1) 2633 break; 2634 } 2635 return (error); 2636} 2637 2638/* 2639 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2640 * referencing STT_GNU_IFUNC symbols is postponed till the other 2641 * relocations are done. The indirect functions specified as 2642 * ifunc are allowed to call other symbols, so we need to have 2643 * objects relocated before asking for resolution from indirects. 2644 * 2645 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2646 * instead of the usual lazy handling of PLT slots. It is 2647 * consistent with how GNU does it. 2648 */ 2649static int 2650resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2651 RtldLockState *lockstate) 2652{ 2653 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2654 return (-1); 2655 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2656 reloc_gnu_ifunc(obj, flags, lockstate) == -1) 2657 return (-1); 2658 return (0); 2659} 2660 2661static int 2662resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags, 2663 RtldLockState *lockstate) 2664{ 2665 Obj_Entry *obj; 2666 2667 for (obj = first; obj != NULL; obj = obj->next) { 2668 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1) 2669 return (-1); 2670 } 2671 return (0); 2672} 2673 2674static int 2675initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2676 RtldLockState *lockstate) 2677{ 2678 Objlist_Entry *elm; 2679 2680 STAILQ_FOREACH(elm, list, link) { 2681 if (resolve_object_ifunc(elm->obj, bind_now, flags, 2682 lockstate) == -1) 2683 return (-1); 2684 } 2685 return (0); 2686} 2687 2688/* 2689 * Cleanup procedure. It will be called (by the atexit mechanism) just 2690 * before the process exits. 2691 */ 2692static void 2693rtld_exit(void) 2694{ 2695 RtldLockState lockstate; 2696 2697 wlock_acquire(rtld_bind_lock, &lockstate); 2698 dbg("rtld_exit()"); 2699 objlist_call_fini(&list_fini, NULL, &lockstate); 2700 /* No need to remove the items from the list, since we are exiting. */ 2701 if (!libmap_disable) 2702 lm_fini(); 2703 lock_release(rtld_bind_lock, &lockstate); 2704} 2705 2706/* 2707 * Iterate over a search path, translate each element, and invoke the 2708 * callback on the result. 2709 */ 2710static void * 2711path_enumerate(const char *path, path_enum_proc callback, void *arg) 2712{ 2713 const char *trans; 2714 if (path == NULL) 2715 return (NULL); 2716 2717 path += strspn(path, ":;"); 2718 while (*path != '\0') { 2719 size_t len; 2720 char *res; 2721 2722 len = strcspn(path, ":;"); 2723 trans = lm_findn(NULL, path, len); 2724 if (trans) 2725 res = callback(trans, strlen(trans), arg); 2726 else 2727 res = callback(path, len, arg); 2728 2729 if (res != NULL) 2730 return (res); 2731 2732 path += len; 2733 path += strspn(path, ":;"); 2734 } 2735 2736 return (NULL); 2737} 2738 2739struct try_library_args { 2740 const char *name; 2741 size_t namelen; 2742 char *buffer; 2743 size_t buflen; 2744}; 2745 2746static void * 2747try_library_path(const char *dir, size_t dirlen, void *param) 2748{ 2749 struct try_library_args *arg; 2750 2751 arg = param; 2752 if (*dir == '/' || trust) { 2753 char *pathname; 2754 2755 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 2756 return (NULL); 2757 2758 pathname = arg->buffer; 2759 strncpy(pathname, dir, dirlen); 2760 pathname[dirlen] = '/'; 2761 strcpy(pathname + dirlen + 1, arg->name); 2762 2763 dbg(" Trying \"%s\"", pathname); 2764 if (access(pathname, F_OK) == 0) { /* We found it */ 2765 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 2766 strcpy(pathname, arg->buffer); 2767 return (pathname); 2768 } 2769 } 2770 return (NULL); 2771} 2772 2773static char * 2774search_library_path(const char *name, const char *path) 2775{ 2776 char *p; 2777 struct try_library_args arg; 2778 2779 if (path == NULL) 2780 return NULL; 2781 2782 arg.name = name; 2783 arg.namelen = strlen(name); 2784 arg.buffer = xmalloc(PATH_MAX); 2785 arg.buflen = PATH_MAX; 2786 2787 p = path_enumerate(path, try_library_path, &arg); 2788 2789 free(arg.buffer); 2790 2791 return (p); 2792} 2793 2794int 2795dlclose(void *handle) 2796{ 2797 Obj_Entry *root; 2798 RtldLockState lockstate; 2799 2800 wlock_acquire(rtld_bind_lock, &lockstate); 2801 root = dlcheck(handle); 2802 if (root == NULL) { 2803 lock_release(rtld_bind_lock, &lockstate); 2804 return -1; 2805 } 2806 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 2807 root->path); 2808 2809 /* Unreference the object and its dependencies. */ 2810 root->dl_refcount--; 2811 2812 if (root->refcount == 1) { 2813 /* 2814 * The object will be no longer referenced, so we must unload it. 2815 * First, call the fini functions. 2816 */ 2817 objlist_call_fini(&list_fini, root, &lockstate); 2818 2819 unref_dag(root); 2820 2821 /* Finish cleaning up the newly-unreferenced objects. */ 2822 GDB_STATE(RT_DELETE,&root->linkmap); 2823 unload_object(root); 2824 GDB_STATE(RT_CONSISTENT,NULL); 2825 } else 2826 unref_dag(root); 2827 2828 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 2829 lock_release(rtld_bind_lock, &lockstate); 2830 return 0; 2831} 2832 2833char * 2834dlerror(void) 2835{ 2836 char *msg = error_message; 2837 error_message = NULL; 2838 return msg; 2839} 2840 2841/* 2842 * This function is deprecated and has no effect. 2843 */ 2844void 2845dllockinit(void *context, 2846 void *(*lock_create)(void *context), 2847 void (*rlock_acquire)(void *lock), 2848 void (*wlock_acquire)(void *lock), 2849 void (*lock_release)(void *lock), 2850 void (*lock_destroy)(void *lock), 2851 void (*context_destroy)(void *context)) 2852{ 2853 static void *cur_context; 2854 static void (*cur_context_destroy)(void *); 2855 2856 /* Just destroy the context from the previous call, if necessary. */ 2857 if (cur_context_destroy != NULL) 2858 cur_context_destroy(cur_context); 2859 cur_context = context; 2860 cur_context_destroy = context_destroy; 2861} 2862 2863void * 2864dlopen(const char *name, int mode) 2865{ 2866 2867 return (rtld_dlopen(name, -1, mode)); 2868} 2869 2870void * 2871fdlopen(int fd, int mode) 2872{ 2873 2874 return (rtld_dlopen(NULL, fd, mode)); 2875} 2876 2877static void * 2878rtld_dlopen(const char *name, int fd, int mode) 2879{ 2880 RtldLockState lockstate; 2881 int lo_flags; 2882 2883 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 2884 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 2885 if (ld_tracing != NULL) { 2886 rlock_acquire(rtld_bind_lock, &lockstate); 2887 if (sigsetjmp(lockstate.env, 0) != 0) 2888 lock_upgrade(rtld_bind_lock, &lockstate); 2889 environ = (char **)*get_program_var_addr("environ", &lockstate); 2890 lock_release(rtld_bind_lock, &lockstate); 2891 } 2892 lo_flags = RTLD_LO_DLOPEN; 2893 if (mode & RTLD_NODELETE) 2894 lo_flags |= RTLD_LO_NODELETE; 2895 if (mode & RTLD_NOLOAD) 2896 lo_flags |= RTLD_LO_NOLOAD; 2897 if (ld_tracing != NULL) 2898 lo_flags |= RTLD_LO_TRACE; 2899 2900 return (dlopen_object(name, fd, obj_main, lo_flags, 2901 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 2902} 2903 2904static void 2905dlopen_cleanup(Obj_Entry *obj) 2906{ 2907 2908 obj->dl_refcount--; 2909 unref_dag(obj); 2910 if (obj->refcount == 0) 2911 unload_object(obj); 2912} 2913 2914static Obj_Entry * 2915dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 2916 int mode, RtldLockState *lockstate) 2917{ 2918 Obj_Entry **old_obj_tail; 2919 Obj_Entry *obj; 2920 Objlist initlist; 2921 RtldLockState mlockstate; 2922 int result; 2923 2924 objlist_init(&initlist); 2925 2926 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 2927 wlock_acquire(rtld_bind_lock, &mlockstate); 2928 lockstate = &mlockstate; 2929 } 2930 GDB_STATE(RT_ADD,NULL); 2931 2932 old_obj_tail = obj_tail; 2933 obj = NULL; 2934 if (name == NULL && fd == -1) { 2935 obj = obj_main; 2936 obj->refcount++; 2937 } else { 2938 obj = load_object(name, fd, refobj, lo_flags); 2939 } 2940 2941 if (obj) { 2942 obj->dl_refcount++; 2943 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 2944 objlist_push_tail(&list_global, obj); 2945 if (*old_obj_tail != NULL) { /* We loaded something new. */ 2946 assert(*old_obj_tail == obj); 2947 result = load_needed_objects(obj, 2948 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 2949 init_dag(obj); 2950 ref_dag(obj); 2951 if (result != -1) 2952 result = rtld_verify_versions(&obj->dagmembers); 2953 if (result != -1 && ld_tracing) 2954 goto trace; 2955 if (result == -1 || relocate_object_dag(obj, 2956 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 2957 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 2958 lockstate) == -1) { 2959 dlopen_cleanup(obj); 2960 obj = NULL; 2961 } else if (lo_flags & RTLD_LO_EARLY) { 2962 /* 2963 * Do not call the init functions for early loaded 2964 * filtees. The image is still not initialized enough 2965 * for them to work. 2966 * 2967 * Our object is found by the global object list and 2968 * will be ordered among all init calls done right 2969 * before transferring control to main. 2970 */ 2971 } else { 2972 /* Make list of init functions to call. */ 2973 initlist_add_objects(obj, &obj->next, &initlist); 2974 } 2975 /* 2976 * Process all no_delete or global objects here, given 2977 * them own DAGs to prevent their dependencies from being 2978 * unloaded. This has to be done after we have loaded all 2979 * of the dependencies, so that we do not miss any. 2980 */ 2981 if (obj != NULL) 2982 process_z(obj); 2983 } else { 2984 /* 2985 * Bump the reference counts for objects on this DAG. If 2986 * this is the first dlopen() call for the object that was 2987 * already loaded as a dependency, initialize the dag 2988 * starting at it. 2989 */ 2990 init_dag(obj); 2991 ref_dag(obj); 2992 2993 if ((lo_flags & RTLD_LO_TRACE) != 0) 2994 goto trace; 2995 } 2996 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 2997 obj->z_nodelete) && !obj->ref_nodel) { 2998 dbg("obj %s nodelete", obj->path); 2999 ref_dag(obj); 3000 obj->z_nodelete = obj->ref_nodel = true; 3001 } 3002 } 3003 3004 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3005 name); 3006 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3007 3008 if (!(lo_flags & RTLD_LO_EARLY)) { 3009 map_stacks_exec(lockstate); 3010 } 3011 3012 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3013 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3014 lockstate) == -1) { 3015 objlist_clear(&initlist); 3016 dlopen_cleanup(obj); 3017 if (lockstate == &mlockstate) 3018 lock_release(rtld_bind_lock, lockstate); 3019 return (NULL); 3020 } 3021 3022 if (!(lo_flags & RTLD_LO_EARLY)) { 3023 /* Call the init functions. */ 3024 objlist_call_init(&initlist, lockstate); 3025 } 3026 objlist_clear(&initlist); 3027 if (lockstate == &mlockstate) 3028 lock_release(rtld_bind_lock, lockstate); 3029 return obj; 3030trace: 3031 trace_loaded_objects(obj); 3032 if (lockstate == &mlockstate) 3033 lock_release(rtld_bind_lock, lockstate); 3034 exit(0); 3035} 3036 3037static void * 3038do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3039 int flags) 3040{ 3041 DoneList donelist; 3042 const Obj_Entry *obj, *defobj; 3043 const Elf_Sym *def; 3044 SymLook req; 3045 RtldLockState lockstate; 3046#ifndef __ia64__ 3047 tls_index ti; 3048#endif 3049 int res; 3050 3051 def = NULL; 3052 defobj = NULL; 3053 symlook_init(&req, name); 3054 req.ventry = ve; 3055 req.flags = flags | SYMLOOK_IN_PLT; 3056 req.lockstate = &lockstate; 3057 3058 rlock_acquire(rtld_bind_lock, &lockstate); 3059 if (sigsetjmp(lockstate.env, 0) != 0) 3060 lock_upgrade(rtld_bind_lock, &lockstate); 3061 if (handle == NULL || handle == RTLD_NEXT || 3062 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3063 3064 if ((obj = obj_from_addr(retaddr)) == NULL) { 3065 _rtld_error("Cannot determine caller's shared object"); 3066 lock_release(rtld_bind_lock, &lockstate); 3067 return NULL; 3068 } 3069 if (handle == NULL) { /* Just the caller's shared object. */ 3070 res = symlook_obj(&req, obj); 3071 if (res == 0) { 3072 def = req.sym_out; 3073 defobj = req.defobj_out; 3074 } 3075 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3076 handle == RTLD_SELF) { /* ... caller included */ 3077 if (handle == RTLD_NEXT) 3078 obj = obj->next; 3079 for (; obj != NULL; obj = obj->next) { 3080 res = symlook_obj(&req, obj); 3081 if (res == 0) { 3082 if (def == NULL || 3083 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3084 def = req.sym_out; 3085 defobj = req.defobj_out; 3086 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3087 break; 3088 } 3089 } 3090 } 3091 /* 3092 * Search the dynamic linker itself, and possibly resolve the 3093 * symbol from there. This is how the application links to 3094 * dynamic linker services such as dlopen. 3095 */ 3096 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3097 res = symlook_obj(&req, &obj_rtld); 3098 if (res == 0) { 3099 def = req.sym_out; 3100 defobj = req.defobj_out; 3101 } 3102 } 3103 } else { 3104 assert(handle == RTLD_DEFAULT); 3105 res = symlook_default(&req, obj); 3106 if (res == 0) { 3107 defobj = req.defobj_out; 3108 def = req.sym_out; 3109 } 3110 } 3111 } else { 3112 if ((obj = dlcheck(handle)) == NULL) { 3113 lock_release(rtld_bind_lock, &lockstate); 3114 return NULL; 3115 } 3116 3117 donelist_init(&donelist); 3118 if (obj->mainprog) { 3119 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3120 res = symlook_global(&req, &donelist); 3121 if (res == 0) { 3122 def = req.sym_out; 3123 defobj = req.defobj_out; 3124 } 3125 /* 3126 * Search the dynamic linker itself, and possibly resolve the 3127 * symbol from there. This is how the application links to 3128 * dynamic linker services such as dlopen. 3129 */ 3130 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3131 res = symlook_obj(&req, &obj_rtld); 3132 if (res == 0) { 3133 def = req.sym_out; 3134 defobj = req.defobj_out; 3135 } 3136 } 3137 } 3138 else { 3139 /* Search the whole DAG rooted at the given object. */ 3140 res = symlook_list(&req, &obj->dagmembers, &donelist); 3141 if (res == 0) { 3142 def = req.sym_out; 3143 defobj = req.defobj_out; 3144 } 3145 } 3146 } 3147 3148 if (def != NULL) { 3149 lock_release(rtld_bind_lock, &lockstate); 3150 3151 /* 3152 * The value required by the caller is derived from the value 3153 * of the symbol. For the ia64 architecture, we need to 3154 * construct a function descriptor which the caller can use to 3155 * call the function with the right 'gp' value. For other 3156 * architectures and for non-functions, the value is simply 3157 * the relocated value of the symbol. 3158 */ 3159 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3160 return (make_function_pointer(def, defobj)); 3161 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3162 return (rtld_resolve_ifunc(defobj, def)); 3163 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3164#ifdef __ia64__ 3165 return (__tls_get_addr(defobj->tlsindex, def->st_value)); 3166#else 3167 ti.ti_module = defobj->tlsindex; 3168 ti.ti_offset = def->st_value; 3169 return (__tls_get_addr(&ti)); 3170#endif 3171 } else 3172 return (defobj->relocbase + def->st_value); 3173 } 3174 3175 _rtld_error("Undefined symbol \"%s\"", name); 3176 lock_release(rtld_bind_lock, &lockstate); 3177 return NULL; 3178} 3179 3180void * 3181dlsym(void *handle, const char *name) 3182{ 3183 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3184 SYMLOOK_DLSYM); 3185} 3186 3187dlfunc_t 3188dlfunc(void *handle, const char *name) 3189{ 3190 union { 3191 void *d; 3192 dlfunc_t f; 3193 } rv; 3194 3195 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3196 SYMLOOK_DLSYM); 3197 return (rv.f); 3198} 3199 3200void * 3201dlvsym(void *handle, const char *name, const char *version) 3202{ 3203 Ver_Entry ventry; 3204 3205 ventry.name = version; 3206 ventry.file = NULL; 3207 ventry.hash = elf_hash(version); 3208 ventry.flags= 0; 3209 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3210 SYMLOOK_DLSYM); 3211} 3212 3213int 3214_rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3215{ 3216 const Obj_Entry *obj; 3217 RtldLockState lockstate; 3218 3219 rlock_acquire(rtld_bind_lock, &lockstate); 3220 obj = obj_from_addr(addr); 3221 if (obj == NULL) { 3222 _rtld_error("No shared object contains address"); 3223 lock_release(rtld_bind_lock, &lockstate); 3224 return (0); 3225 } 3226 rtld_fill_dl_phdr_info(obj, phdr_info); 3227 lock_release(rtld_bind_lock, &lockstate); 3228 return (1); 3229} 3230 3231int 3232dladdr(const void *addr, Dl_info *info) 3233{ 3234 const Obj_Entry *obj; 3235 const Elf_Sym *def; 3236 void *symbol_addr; 3237 unsigned long symoffset; 3238 RtldLockState lockstate; 3239 3240 rlock_acquire(rtld_bind_lock, &lockstate); 3241 obj = obj_from_addr(addr); 3242 if (obj == NULL) { 3243 _rtld_error("No shared object contains address"); 3244 lock_release(rtld_bind_lock, &lockstate); 3245 return 0; 3246 } 3247 info->dli_fname = obj->path; 3248 info->dli_fbase = obj->mapbase; 3249 info->dli_saddr = (void *)0; 3250 info->dli_sname = NULL; 3251 3252 /* 3253 * Walk the symbol list looking for the symbol whose address is 3254 * closest to the address sent in. 3255 */ 3256 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3257 def = obj->symtab + symoffset; 3258 3259 /* 3260 * For skip the symbol if st_shndx is either SHN_UNDEF or 3261 * SHN_COMMON. 3262 */ 3263 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3264 continue; 3265 3266 /* 3267 * If the symbol is greater than the specified address, or if it 3268 * is further away from addr than the current nearest symbol, 3269 * then reject it. 3270 */ 3271 symbol_addr = obj->relocbase + def->st_value; 3272 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3273 continue; 3274 3275 /* Update our idea of the nearest symbol. */ 3276 info->dli_sname = obj->strtab + def->st_name; 3277 info->dli_saddr = symbol_addr; 3278 3279 /* Exact match? */ 3280 if (info->dli_saddr == addr) 3281 break; 3282 } 3283 lock_release(rtld_bind_lock, &lockstate); 3284 return 1; 3285} 3286 3287int 3288dlinfo(void *handle, int request, void *p) 3289{ 3290 const Obj_Entry *obj; 3291 RtldLockState lockstate; 3292 int error; 3293 3294 rlock_acquire(rtld_bind_lock, &lockstate); 3295 3296 if (handle == NULL || handle == RTLD_SELF) { 3297 void *retaddr; 3298 3299 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3300 if ((obj = obj_from_addr(retaddr)) == NULL) 3301 _rtld_error("Cannot determine caller's shared object"); 3302 } else 3303 obj = dlcheck(handle); 3304 3305 if (obj == NULL) { 3306 lock_release(rtld_bind_lock, &lockstate); 3307 return (-1); 3308 } 3309 3310 error = 0; 3311 switch (request) { 3312 case RTLD_DI_LINKMAP: 3313 *((struct link_map const **)p) = &obj->linkmap; 3314 break; 3315 case RTLD_DI_ORIGIN: 3316 error = rtld_dirname(obj->path, p); 3317 break; 3318 3319 case RTLD_DI_SERINFOSIZE: 3320 case RTLD_DI_SERINFO: 3321 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3322 break; 3323 3324 default: 3325 _rtld_error("Invalid request %d passed to dlinfo()", request); 3326 error = -1; 3327 } 3328 3329 lock_release(rtld_bind_lock, &lockstate); 3330 3331 return (error); 3332} 3333 3334static void 3335rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3336{ 3337 3338 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3339 phdr_info->dlpi_name = obj->path; 3340 phdr_info->dlpi_phdr = obj->phdr; 3341 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3342 phdr_info->dlpi_tls_modid = obj->tlsindex; 3343 phdr_info->dlpi_tls_data = obj->tlsinit; 3344 phdr_info->dlpi_adds = obj_loads; 3345 phdr_info->dlpi_subs = obj_loads - obj_count; 3346} 3347 3348int 3349dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3350{ 3351 struct dl_phdr_info phdr_info; 3352 const Obj_Entry *obj; 3353 RtldLockState bind_lockstate, phdr_lockstate; 3354 int error; 3355 3356 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3357 rlock_acquire(rtld_bind_lock, &bind_lockstate); 3358 3359 error = 0; 3360 3361 for (obj = obj_list; obj != NULL; obj = obj->next) { 3362 rtld_fill_dl_phdr_info(obj, &phdr_info); 3363 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0) 3364 break; 3365 3366 } 3367 lock_release(rtld_bind_lock, &bind_lockstate); 3368 lock_release(rtld_phdr_lock, &phdr_lockstate); 3369 3370 return (error); 3371} 3372 3373static void * 3374fill_search_info(const char *dir, size_t dirlen, void *param) 3375{ 3376 struct fill_search_info_args *arg; 3377 3378 arg = param; 3379 3380 if (arg->request == RTLD_DI_SERINFOSIZE) { 3381 arg->serinfo->dls_cnt ++; 3382 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3383 } else { 3384 struct dl_serpath *s_entry; 3385 3386 s_entry = arg->serpath; 3387 s_entry->dls_name = arg->strspace; 3388 s_entry->dls_flags = arg->flags; 3389 3390 strncpy(arg->strspace, dir, dirlen); 3391 arg->strspace[dirlen] = '\0'; 3392 3393 arg->strspace += dirlen + 1; 3394 arg->serpath++; 3395 } 3396 3397 return (NULL); 3398} 3399 3400static int 3401do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3402{ 3403 struct dl_serinfo _info; 3404 struct fill_search_info_args args; 3405 3406 args.request = RTLD_DI_SERINFOSIZE; 3407 args.serinfo = &_info; 3408 3409 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3410 _info.dls_cnt = 0; 3411 3412 path_enumerate(obj->rpath, fill_search_info, &args); 3413 path_enumerate(ld_library_path, fill_search_info, &args); 3414 path_enumerate(obj->runpath, fill_search_info, &args); 3415 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args); 3416 if (!obj->z_nodeflib) 3417 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 3418 3419 3420 if (request == RTLD_DI_SERINFOSIZE) { 3421 info->dls_size = _info.dls_size; 3422 info->dls_cnt = _info.dls_cnt; 3423 return (0); 3424 } 3425 3426 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3427 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3428 return (-1); 3429 } 3430 3431 args.request = RTLD_DI_SERINFO; 3432 args.serinfo = info; 3433 args.serpath = &info->dls_serpath[0]; 3434 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3435 3436 args.flags = LA_SER_RUNPATH; 3437 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 3438 return (-1); 3439 3440 args.flags = LA_SER_LIBPATH; 3441 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 3442 return (-1); 3443 3444 args.flags = LA_SER_RUNPATH; 3445 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL) 3446 return (-1); 3447 3448 args.flags = LA_SER_CONFIG; 3449 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args) 3450 != NULL) 3451 return (-1); 3452 3453 args.flags = LA_SER_DEFAULT; 3454 if (!obj->z_nodeflib && 3455 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 3456 return (-1); 3457 return (0); 3458} 3459 3460static int 3461rtld_dirname(const char *path, char *bname) 3462{ 3463 const char *endp; 3464 3465 /* Empty or NULL string gets treated as "." */ 3466 if (path == NULL || *path == '\0') { 3467 bname[0] = '.'; 3468 bname[1] = '\0'; 3469 return (0); 3470 } 3471 3472 /* Strip trailing slashes */ 3473 endp = path + strlen(path) - 1; 3474 while (endp > path && *endp == '/') 3475 endp--; 3476 3477 /* Find the start of the dir */ 3478 while (endp > path && *endp != '/') 3479 endp--; 3480 3481 /* Either the dir is "/" or there are no slashes */ 3482 if (endp == path) { 3483 bname[0] = *endp == '/' ? '/' : '.'; 3484 bname[1] = '\0'; 3485 return (0); 3486 } else { 3487 do { 3488 endp--; 3489 } while (endp > path && *endp == '/'); 3490 } 3491 3492 if (endp - path + 2 > PATH_MAX) 3493 { 3494 _rtld_error("Filename is too long: %s", path); 3495 return(-1); 3496 } 3497 3498 strncpy(bname, path, endp - path + 1); 3499 bname[endp - path + 1] = '\0'; 3500 return (0); 3501} 3502 3503static int 3504rtld_dirname_abs(const char *path, char *base) 3505{ 3506 char *last; 3507 3508 if (realpath(path, base) == NULL) 3509 return (-1); 3510 dbg("%s -> %s", path, base); 3511 last = strrchr(base, '/'); 3512 if (last == NULL) 3513 return (-1); 3514 if (last != base) 3515 *last = '\0'; 3516 return (0); 3517} 3518 3519static void 3520linkmap_add(Obj_Entry *obj) 3521{ 3522 struct link_map *l = &obj->linkmap; 3523 struct link_map *prev; 3524 3525 obj->linkmap.l_name = obj->path; 3526 obj->linkmap.l_addr = obj->mapbase; 3527 obj->linkmap.l_ld = obj->dynamic; 3528#ifdef __mips__ 3529 /* GDB needs load offset on MIPS to use the symbols */ 3530 obj->linkmap.l_offs = obj->relocbase; 3531#endif 3532 3533 if (r_debug.r_map == NULL) { 3534 r_debug.r_map = l; 3535 return; 3536 } 3537 3538 /* 3539 * Scan to the end of the list, but not past the entry for the 3540 * dynamic linker, which we want to keep at the very end. 3541 */ 3542 for (prev = r_debug.r_map; 3543 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3544 prev = prev->l_next) 3545 ; 3546 3547 /* Link in the new entry. */ 3548 l->l_prev = prev; 3549 l->l_next = prev->l_next; 3550 if (l->l_next != NULL) 3551 l->l_next->l_prev = l; 3552 prev->l_next = l; 3553} 3554 3555static void 3556linkmap_delete(Obj_Entry *obj) 3557{ 3558 struct link_map *l = &obj->linkmap; 3559 3560 if (l->l_prev == NULL) { 3561 if ((r_debug.r_map = l->l_next) != NULL) 3562 l->l_next->l_prev = NULL; 3563 return; 3564 } 3565 3566 if ((l->l_prev->l_next = l->l_next) != NULL) 3567 l->l_next->l_prev = l->l_prev; 3568} 3569 3570/* 3571 * Function for the debugger to set a breakpoint on to gain control. 3572 * 3573 * The two parameters allow the debugger to easily find and determine 3574 * what the runtime loader is doing and to whom it is doing it. 3575 * 3576 * When the loadhook trap is hit (r_debug_state, set at program 3577 * initialization), the arguments can be found on the stack: 3578 * 3579 * +8 struct link_map *m 3580 * +4 struct r_debug *rd 3581 * +0 RetAddr 3582 */ 3583void 3584r_debug_state(struct r_debug* rd, struct link_map *m) 3585{ 3586 /* 3587 * The following is a hack to force the compiler to emit calls to 3588 * this function, even when optimizing. If the function is empty, 3589 * the compiler is not obliged to emit any code for calls to it, 3590 * even when marked __noinline. However, gdb depends on those 3591 * calls being made. 3592 */ 3593 __compiler_membar(); 3594} 3595 3596/* 3597 * A function called after init routines have completed. This can be used to 3598 * break before a program's entry routine is called, and can be used when 3599 * main is not available in the symbol table. 3600 */ 3601void 3602_r_debug_postinit(struct link_map *m) 3603{ 3604 3605 /* See r_debug_state(). */ 3606 __compiler_membar(); 3607} 3608 3609/* 3610 * Get address of the pointer variable in the main program. 3611 * Prefer non-weak symbol over the weak one. 3612 */ 3613static const void ** 3614get_program_var_addr(const char *name, RtldLockState *lockstate) 3615{ 3616 SymLook req; 3617 DoneList donelist; 3618 3619 symlook_init(&req, name); 3620 req.lockstate = lockstate; 3621 donelist_init(&donelist); 3622 if (symlook_global(&req, &donelist) != 0) 3623 return (NULL); 3624 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 3625 return ((const void **)make_function_pointer(req.sym_out, 3626 req.defobj_out)); 3627 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 3628 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 3629 else 3630 return ((const void **)(req.defobj_out->relocbase + 3631 req.sym_out->st_value)); 3632} 3633 3634/* 3635 * Set a pointer variable in the main program to the given value. This 3636 * is used to set key variables such as "environ" before any of the 3637 * init functions are called. 3638 */ 3639static void 3640set_program_var(const char *name, const void *value) 3641{ 3642 const void **addr; 3643 3644 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 3645 dbg("\"%s\": *%p <-- %p", name, addr, value); 3646 *addr = value; 3647 } 3648} 3649 3650/* 3651 * Search the global objects, including dependencies and main object, 3652 * for the given symbol. 3653 */ 3654static int 3655symlook_global(SymLook *req, DoneList *donelist) 3656{ 3657 SymLook req1; 3658 const Objlist_Entry *elm; 3659 int res; 3660 3661 symlook_init_from_req(&req1, req); 3662 3663 /* Search all objects loaded at program start up. */ 3664 if (req->defobj_out == NULL || 3665 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3666 res = symlook_list(&req1, &list_main, donelist); 3667 if (res == 0 && (req->defobj_out == NULL || 3668 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3669 req->sym_out = req1.sym_out; 3670 req->defobj_out = req1.defobj_out; 3671 assert(req->defobj_out != NULL); 3672 } 3673 } 3674 3675 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 3676 STAILQ_FOREACH(elm, &list_global, link) { 3677 if (req->defobj_out != NULL && 3678 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3679 break; 3680 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 3681 if (res == 0 && (req->defobj_out == NULL || 3682 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3683 req->sym_out = req1.sym_out; 3684 req->defobj_out = req1.defobj_out; 3685 assert(req->defobj_out != NULL); 3686 } 3687 } 3688 3689 return (req->sym_out != NULL ? 0 : ESRCH); 3690} 3691 3692/* 3693 * Given a symbol name in a referencing object, find the corresponding 3694 * definition of the symbol. Returns a pointer to the symbol, or NULL if 3695 * no definition was found. Returns a pointer to the Obj_Entry of the 3696 * defining object via the reference parameter DEFOBJ_OUT. 3697 */ 3698static int 3699symlook_default(SymLook *req, const Obj_Entry *refobj) 3700{ 3701 DoneList donelist; 3702 const Objlist_Entry *elm; 3703 SymLook req1; 3704 int res; 3705 3706 donelist_init(&donelist); 3707 symlook_init_from_req(&req1, req); 3708 3709 /* Look first in the referencing object if linked symbolically. */ 3710 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 3711 res = symlook_obj(&req1, refobj); 3712 if (res == 0) { 3713 req->sym_out = req1.sym_out; 3714 req->defobj_out = req1.defobj_out; 3715 assert(req->defobj_out != NULL); 3716 } 3717 } 3718 3719 symlook_global(req, &donelist); 3720 3721 /* Search all dlopened DAGs containing the referencing object. */ 3722 STAILQ_FOREACH(elm, &refobj->dldags, link) { 3723 if (req->sym_out != NULL && 3724 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3725 break; 3726 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 3727 if (res == 0 && (req->sym_out == NULL || 3728 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3729 req->sym_out = req1.sym_out; 3730 req->defobj_out = req1.defobj_out; 3731 assert(req->defobj_out != NULL); 3732 } 3733 } 3734 3735 /* 3736 * Search the dynamic linker itself, and possibly resolve the 3737 * symbol from there. This is how the application links to 3738 * dynamic linker services such as dlopen. 3739 */ 3740 if (req->sym_out == NULL || 3741 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3742 res = symlook_obj(&req1, &obj_rtld); 3743 if (res == 0) { 3744 req->sym_out = req1.sym_out; 3745 req->defobj_out = req1.defobj_out; 3746 assert(req->defobj_out != NULL); 3747 } 3748 } 3749 3750 return (req->sym_out != NULL ? 0 : ESRCH); 3751} 3752 3753static int 3754symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 3755{ 3756 const Elf_Sym *def; 3757 const Obj_Entry *defobj; 3758 const Objlist_Entry *elm; 3759 SymLook req1; 3760 int res; 3761 3762 def = NULL; 3763 defobj = NULL; 3764 STAILQ_FOREACH(elm, objlist, link) { 3765 if (donelist_check(dlp, elm->obj)) 3766 continue; 3767 symlook_init_from_req(&req1, req); 3768 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 3769 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3770 def = req1.sym_out; 3771 defobj = req1.defobj_out; 3772 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3773 break; 3774 } 3775 } 3776 } 3777 if (def != NULL) { 3778 req->sym_out = def; 3779 req->defobj_out = defobj; 3780 return (0); 3781 } 3782 return (ESRCH); 3783} 3784 3785/* 3786 * Search the chain of DAGS cointed to by the given Needed_Entry 3787 * for a symbol of the given name. Each DAG is scanned completely 3788 * before advancing to the next one. Returns a pointer to the symbol, 3789 * or NULL if no definition was found. 3790 */ 3791static int 3792symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 3793{ 3794 const Elf_Sym *def; 3795 const Needed_Entry *n; 3796 const Obj_Entry *defobj; 3797 SymLook req1; 3798 int res; 3799 3800 def = NULL; 3801 defobj = NULL; 3802 symlook_init_from_req(&req1, req); 3803 for (n = needed; n != NULL; n = n->next) { 3804 if (n->obj == NULL || 3805 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 3806 continue; 3807 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3808 def = req1.sym_out; 3809 defobj = req1.defobj_out; 3810 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3811 break; 3812 } 3813 } 3814 if (def != NULL) { 3815 req->sym_out = def; 3816 req->defobj_out = defobj; 3817 return (0); 3818 } 3819 return (ESRCH); 3820} 3821 3822/* 3823 * Search the symbol table of a single shared object for a symbol of 3824 * the given name and version, if requested. Returns a pointer to the 3825 * symbol, or NULL if no definition was found. If the object is 3826 * filter, return filtered symbol from filtee. 3827 * 3828 * The symbol's hash value is passed in for efficiency reasons; that 3829 * eliminates many recomputations of the hash value. 3830 */ 3831int 3832symlook_obj(SymLook *req, const Obj_Entry *obj) 3833{ 3834 DoneList donelist; 3835 SymLook req1; 3836 int flags, res, mres; 3837 3838 /* 3839 * If there is at least one valid hash at this point, we prefer to 3840 * use the faster GNU version if available. 3841 */ 3842 if (obj->valid_hash_gnu) 3843 mres = symlook_obj1_gnu(req, obj); 3844 else if (obj->valid_hash_sysv) 3845 mres = symlook_obj1_sysv(req, obj); 3846 else 3847 return (EINVAL); 3848 3849 if (mres == 0) { 3850 if (obj->needed_filtees != NULL) { 3851 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3852 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3853 donelist_init(&donelist); 3854 symlook_init_from_req(&req1, req); 3855 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 3856 if (res == 0) { 3857 req->sym_out = req1.sym_out; 3858 req->defobj_out = req1.defobj_out; 3859 } 3860 return (res); 3861 } 3862 if (obj->needed_aux_filtees != NULL) { 3863 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3864 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3865 donelist_init(&donelist); 3866 symlook_init_from_req(&req1, req); 3867 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 3868 if (res == 0) { 3869 req->sym_out = req1.sym_out; 3870 req->defobj_out = req1.defobj_out; 3871 return (res); 3872 } 3873 } 3874 } 3875 return (mres); 3876} 3877 3878/* Symbol match routine common to both hash functions */ 3879static bool 3880matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 3881 const unsigned long symnum) 3882{ 3883 Elf_Versym verndx; 3884 const Elf_Sym *symp; 3885 const char *strp; 3886 3887 symp = obj->symtab + symnum; 3888 strp = obj->strtab + symp->st_name; 3889 3890 switch (ELF_ST_TYPE(symp->st_info)) { 3891 case STT_FUNC: 3892 case STT_NOTYPE: 3893 case STT_OBJECT: 3894 case STT_COMMON: 3895 case STT_GNU_IFUNC: 3896 if (symp->st_value == 0) 3897 return (false); 3898 /* fallthrough */ 3899 case STT_TLS: 3900 if (symp->st_shndx != SHN_UNDEF) 3901 break; 3902#ifndef __mips__ 3903 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 3904 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 3905 break; 3906 /* fallthrough */ 3907#endif 3908 default: 3909 return (false); 3910 } 3911 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 3912 return (false); 3913 3914 if (req->ventry == NULL) { 3915 if (obj->versyms != NULL) { 3916 verndx = VER_NDX(obj->versyms[symnum]); 3917 if (verndx > obj->vernum) { 3918 _rtld_error( 3919 "%s: symbol %s references wrong version %d", 3920 obj->path, obj->strtab + symnum, verndx); 3921 return (false); 3922 } 3923 /* 3924 * If we are not called from dlsym (i.e. this 3925 * is a normal relocation from unversioned 3926 * binary), accept the symbol immediately if 3927 * it happens to have first version after this 3928 * shared object became versioned. Otherwise, 3929 * if symbol is versioned and not hidden, 3930 * remember it. If it is the only symbol with 3931 * this name exported by the shared object, it 3932 * will be returned as a match by the calling 3933 * function. If symbol is global (verndx < 2) 3934 * accept it unconditionally. 3935 */ 3936 if ((req->flags & SYMLOOK_DLSYM) == 0 && 3937 verndx == VER_NDX_GIVEN) { 3938 result->sym_out = symp; 3939 return (true); 3940 } 3941 else if (verndx >= VER_NDX_GIVEN) { 3942 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 3943 == 0) { 3944 if (result->vsymp == NULL) 3945 result->vsymp = symp; 3946 result->vcount++; 3947 } 3948 return (false); 3949 } 3950 } 3951 result->sym_out = symp; 3952 return (true); 3953 } 3954 if (obj->versyms == NULL) { 3955 if (object_match_name(obj, req->ventry->name)) { 3956 _rtld_error("%s: object %s should provide version %s " 3957 "for symbol %s", obj_rtld.path, obj->path, 3958 req->ventry->name, obj->strtab + symnum); 3959 return (false); 3960 } 3961 } else { 3962 verndx = VER_NDX(obj->versyms[symnum]); 3963 if (verndx > obj->vernum) { 3964 _rtld_error("%s: symbol %s references wrong version %d", 3965 obj->path, obj->strtab + symnum, verndx); 3966 return (false); 3967 } 3968 if (obj->vertab[verndx].hash != req->ventry->hash || 3969 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 3970 /* 3971 * Version does not match. Look if this is a 3972 * global symbol and if it is not hidden. If 3973 * global symbol (verndx < 2) is available, 3974 * use it. Do not return symbol if we are 3975 * called by dlvsym, because dlvsym looks for 3976 * a specific version and default one is not 3977 * what dlvsym wants. 3978 */ 3979 if ((req->flags & SYMLOOK_DLSYM) || 3980 (verndx >= VER_NDX_GIVEN) || 3981 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 3982 return (false); 3983 } 3984 } 3985 result->sym_out = symp; 3986 return (true); 3987} 3988 3989/* 3990 * Search for symbol using SysV hash function. 3991 * obj->buckets is known not to be NULL at this point; the test for this was 3992 * performed with the obj->valid_hash_sysv assignment. 3993 */ 3994static int 3995symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 3996{ 3997 unsigned long symnum; 3998 Sym_Match_Result matchres; 3999 4000 matchres.sym_out = NULL; 4001 matchres.vsymp = NULL; 4002 matchres.vcount = 0; 4003 4004 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4005 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4006 if (symnum >= obj->nchains) 4007 return (ESRCH); /* Bad object */ 4008 4009 if (matched_symbol(req, obj, &matchres, symnum)) { 4010 req->sym_out = matchres.sym_out; 4011 req->defobj_out = obj; 4012 return (0); 4013 } 4014 } 4015 if (matchres.vcount == 1) { 4016 req->sym_out = matchres.vsymp; 4017 req->defobj_out = obj; 4018 return (0); 4019 } 4020 return (ESRCH); 4021} 4022 4023/* Search for symbol using GNU hash function */ 4024static int 4025symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4026{ 4027 Elf_Addr bloom_word; 4028 const Elf32_Word *hashval; 4029 Elf32_Word bucket; 4030 Sym_Match_Result matchres; 4031 unsigned int h1, h2; 4032 unsigned long symnum; 4033 4034 matchres.sym_out = NULL; 4035 matchres.vsymp = NULL; 4036 matchres.vcount = 0; 4037 4038 /* Pick right bitmask word from Bloom filter array */ 4039 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4040 obj->maskwords_bm_gnu]; 4041 4042 /* Calculate modulus word size of gnu hash and its derivative */ 4043 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4044 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4045 4046 /* Filter out the "definitely not in set" queries */ 4047 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4048 return (ESRCH); 4049 4050 /* Locate hash chain and corresponding value element*/ 4051 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4052 if (bucket == 0) 4053 return (ESRCH); 4054 hashval = &obj->chain_zero_gnu[bucket]; 4055 do { 4056 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4057 symnum = hashval - obj->chain_zero_gnu; 4058 if (matched_symbol(req, obj, &matchres, symnum)) { 4059 req->sym_out = matchres.sym_out; 4060 req->defobj_out = obj; 4061 return (0); 4062 } 4063 } 4064 } while ((*hashval++ & 1) == 0); 4065 if (matchres.vcount == 1) { 4066 req->sym_out = matchres.vsymp; 4067 req->defobj_out = obj; 4068 return (0); 4069 } 4070 return (ESRCH); 4071} 4072 4073static void 4074trace_loaded_objects(Obj_Entry *obj) 4075{ 4076 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4077 int c; 4078 4079 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 4080 main_local = ""; 4081 4082 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL) 4083 fmt1 = "\t%o => %p (%x)\n"; 4084 4085 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL) 4086 fmt2 = "\t%o (%x)\n"; 4087 4088 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL"); 4089 4090 for (; obj; obj = obj->next) { 4091 Needed_Entry *needed; 4092 char *name, *path; 4093 bool is_lib; 4094 4095 if (list_containers && obj->needed != NULL) 4096 rtld_printf("%s:\n", obj->path); 4097 for (needed = obj->needed; needed; needed = needed->next) { 4098 if (needed->obj != NULL) { 4099 if (needed->obj->traced && !list_containers) 4100 continue; 4101 needed->obj->traced = true; 4102 path = needed->obj->path; 4103 } else 4104 path = "not found"; 4105 4106 name = (char *)obj->strtab + needed->name; 4107 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4108 4109 fmt = is_lib ? fmt1 : fmt2; 4110 while ((c = *fmt++) != '\0') { 4111 switch (c) { 4112 default: 4113 rtld_putchar(c); 4114 continue; 4115 case '\\': 4116 switch (c = *fmt) { 4117 case '\0': 4118 continue; 4119 case 'n': 4120 rtld_putchar('\n'); 4121 break; 4122 case 't': 4123 rtld_putchar('\t'); 4124 break; 4125 } 4126 break; 4127 case '%': 4128 switch (c = *fmt) { 4129 case '\0': 4130 continue; 4131 case '%': 4132 default: 4133 rtld_putchar(c); 4134 break; 4135 case 'A': 4136 rtld_putstr(main_local); 4137 break; 4138 case 'a': 4139 rtld_putstr(obj_main->path); 4140 break; 4141 case 'o': 4142 rtld_putstr(name); 4143 break; 4144#if 0 4145 case 'm': 4146 rtld_printf("%d", sodp->sod_major); 4147 break; 4148 case 'n': 4149 rtld_printf("%d", sodp->sod_minor); 4150 break; 4151#endif 4152 case 'p': 4153 rtld_putstr(path); 4154 break; 4155 case 'x': 4156 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4157 0); 4158 break; 4159 } 4160 break; 4161 } 4162 ++fmt; 4163 } 4164 } 4165 } 4166} 4167 4168/* 4169 * Unload a dlopened object and its dependencies from memory and from 4170 * our data structures. It is assumed that the DAG rooted in the 4171 * object has already been unreferenced, and that the object has a 4172 * reference count of 0. 4173 */ 4174static void 4175unload_object(Obj_Entry *root) 4176{ 4177 Obj_Entry *obj; 4178 Obj_Entry **linkp; 4179 4180 assert(root->refcount == 0); 4181 4182 /* 4183 * Pass over the DAG removing unreferenced objects from 4184 * appropriate lists. 4185 */ 4186 unlink_object(root); 4187 4188 /* Unmap all objects that are no longer referenced. */ 4189 linkp = &obj_list->next; 4190 while ((obj = *linkp) != NULL) { 4191 if (obj->refcount == 0) { 4192 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 4193 obj->path); 4194 dbg("unloading \"%s\"", obj->path); 4195 unload_filtees(root); 4196 munmap(obj->mapbase, obj->mapsize); 4197 linkmap_delete(obj); 4198 *linkp = obj->next; 4199 obj_count--; 4200 obj_free(obj); 4201 } else 4202 linkp = &obj->next; 4203 } 4204 obj_tail = linkp; 4205} 4206 4207static void 4208unlink_object(Obj_Entry *root) 4209{ 4210 Objlist_Entry *elm; 4211 4212 if (root->refcount == 0) { 4213 /* Remove the object from the RTLD_GLOBAL list. */ 4214 objlist_remove(&list_global, root); 4215 4216 /* Remove the object from all objects' DAG lists. */ 4217 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4218 objlist_remove(&elm->obj->dldags, root); 4219 if (elm->obj != root) 4220 unlink_object(elm->obj); 4221 } 4222 } 4223} 4224 4225static void 4226ref_dag(Obj_Entry *root) 4227{ 4228 Objlist_Entry *elm; 4229 4230 assert(root->dag_inited); 4231 STAILQ_FOREACH(elm, &root->dagmembers, link) 4232 elm->obj->refcount++; 4233} 4234 4235static void 4236unref_dag(Obj_Entry *root) 4237{ 4238 Objlist_Entry *elm; 4239 4240 assert(root->dag_inited); 4241 STAILQ_FOREACH(elm, &root->dagmembers, link) 4242 elm->obj->refcount--; 4243} 4244 4245/* 4246 * Common code for MD __tls_get_addr(). 4247 */ 4248static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4249static void * 4250tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4251{ 4252 Elf_Addr *newdtv, *dtv; 4253 RtldLockState lockstate; 4254 int to_copy; 4255 4256 dtv = *dtvp; 4257 /* Check dtv generation in case new modules have arrived */ 4258 if (dtv[0] != tls_dtv_generation) { 4259 wlock_acquire(rtld_bind_lock, &lockstate); 4260 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4261 to_copy = dtv[1]; 4262 if (to_copy > tls_max_index) 4263 to_copy = tls_max_index; 4264 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4265 newdtv[0] = tls_dtv_generation; 4266 newdtv[1] = tls_max_index; 4267 free(dtv); 4268 lock_release(rtld_bind_lock, &lockstate); 4269 dtv = *dtvp = newdtv; 4270 } 4271 4272 /* Dynamically allocate module TLS if necessary */ 4273 if (dtv[index + 1] == 0) { 4274 /* Signal safe, wlock will block out signals. */ 4275 wlock_acquire(rtld_bind_lock, &lockstate); 4276 if (!dtv[index + 1]) 4277 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4278 lock_release(rtld_bind_lock, &lockstate); 4279 } 4280 return ((void *)(dtv[index + 1] + offset)); 4281} 4282 4283void * 4284tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4285{ 4286 Elf_Addr *dtv; 4287 4288 dtv = *dtvp; 4289 /* Check dtv generation in case new modules have arrived */ 4290 if (__predict_true(dtv[0] == tls_dtv_generation && 4291 dtv[index + 1] != 0)) 4292 return ((void *)(dtv[index + 1] + offset)); 4293 return (tls_get_addr_slow(dtvp, index, offset)); 4294} 4295 4296#if defined(__arm__) || defined(__ia64__) || defined(__mips__) || defined(__powerpc__) 4297 4298/* 4299 * Allocate Static TLS using the Variant I method. 4300 */ 4301void * 4302allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4303{ 4304 Obj_Entry *obj; 4305 char *tcb; 4306 Elf_Addr **tls; 4307 Elf_Addr *dtv; 4308 Elf_Addr addr; 4309 int i; 4310 4311 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4312 return (oldtcb); 4313 4314 assert(tcbsize >= TLS_TCB_SIZE); 4315 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 4316 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 4317 4318 if (oldtcb != NULL) { 4319 memcpy(tls, oldtcb, tls_static_space); 4320 free(oldtcb); 4321 4322 /* Adjust the DTV. */ 4323 dtv = tls[0]; 4324 for (i = 0; i < dtv[1]; i++) { 4325 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4326 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4327 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 4328 } 4329 } 4330 } else { 4331 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4332 tls[0] = dtv; 4333 dtv[0] = tls_dtv_generation; 4334 dtv[1] = tls_max_index; 4335 4336 for (obj = objs; obj; obj = obj->next) { 4337 if (obj->tlsoffset > 0) { 4338 addr = (Elf_Addr)tls + obj->tlsoffset; 4339 if (obj->tlsinitsize > 0) 4340 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4341 if (obj->tlssize > obj->tlsinitsize) 4342 memset((void*) (addr + obj->tlsinitsize), 0, 4343 obj->tlssize - obj->tlsinitsize); 4344 dtv[obj->tlsindex + 1] = addr; 4345 } 4346 } 4347 } 4348 4349 return (tcb); 4350} 4351 4352void 4353free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4354{ 4355 Elf_Addr *dtv; 4356 Elf_Addr tlsstart, tlsend; 4357 int dtvsize, i; 4358 4359 assert(tcbsize >= TLS_TCB_SIZE); 4360 4361 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 4362 tlsend = tlsstart + tls_static_space; 4363 4364 dtv = *(Elf_Addr **)tlsstart; 4365 dtvsize = dtv[1]; 4366 for (i = 0; i < dtvsize; i++) { 4367 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4368 free((void*)dtv[i+2]); 4369 } 4370 } 4371 free(dtv); 4372 free(tcb); 4373} 4374 4375#endif 4376 4377#if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 4378 4379/* 4380 * Allocate Static TLS using the Variant II method. 4381 */ 4382void * 4383allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4384{ 4385 Obj_Entry *obj; 4386 size_t size, ralign; 4387 char *tls; 4388 Elf_Addr *dtv, *olddtv; 4389 Elf_Addr segbase, oldsegbase, addr; 4390 int i; 4391 4392 ralign = tcbalign; 4393 if (tls_static_max_align > ralign) 4394 ralign = tls_static_max_align; 4395 size = round(tls_static_space, ralign) + round(tcbsize, ralign); 4396 4397 assert(tcbsize >= 2*sizeof(Elf_Addr)); 4398 tls = malloc_aligned(size, ralign); 4399 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4400 4401 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign)); 4402 ((Elf_Addr*)segbase)[0] = segbase; 4403 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 4404 4405 dtv[0] = tls_dtv_generation; 4406 dtv[1] = tls_max_index; 4407 4408 if (oldtls) { 4409 /* 4410 * Copy the static TLS block over whole. 4411 */ 4412 oldsegbase = (Elf_Addr) oldtls; 4413 memcpy((void *)(segbase - tls_static_space), 4414 (const void *)(oldsegbase - tls_static_space), 4415 tls_static_space); 4416 4417 /* 4418 * If any dynamic TLS blocks have been created tls_get_addr(), 4419 * move them over. 4420 */ 4421 olddtv = ((Elf_Addr**)oldsegbase)[1]; 4422 for (i = 0; i < olddtv[1]; i++) { 4423 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 4424 dtv[i+2] = olddtv[i+2]; 4425 olddtv[i+2] = 0; 4426 } 4427 } 4428 4429 /* 4430 * We assume that this block was the one we created with 4431 * allocate_initial_tls(). 4432 */ 4433 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 4434 } else { 4435 for (obj = objs; obj; obj = obj->next) { 4436 if (obj->tlsoffset) { 4437 addr = segbase - obj->tlsoffset; 4438 memset((void*) (addr + obj->tlsinitsize), 4439 0, obj->tlssize - obj->tlsinitsize); 4440 if (obj->tlsinit) 4441 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4442 dtv[obj->tlsindex + 1] = addr; 4443 } 4444 } 4445 } 4446 4447 return (void*) segbase; 4448} 4449 4450void 4451free_tls(void *tls, size_t tcbsize, size_t tcbalign) 4452{ 4453 Elf_Addr* dtv; 4454 size_t size, ralign; 4455 int dtvsize, i; 4456 Elf_Addr tlsstart, tlsend; 4457 4458 /* 4459 * Figure out the size of the initial TLS block so that we can 4460 * find stuff which ___tls_get_addr() allocated dynamically. 4461 */ 4462 ralign = tcbalign; 4463 if (tls_static_max_align > ralign) 4464 ralign = tls_static_max_align; 4465 size = round(tls_static_space, ralign); 4466 4467 dtv = ((Elf_Addr**)tls)[1]; 4468 dtvsize = dtv[1]; 4469 tlsend = (Elf_Addr) tls; 4470 tlsstart = tlsend - size; 4471 for (i = 0; i < dtvsize; i++) { 4472 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 4473 free_aligned((void *)dtv[i + 2]); 4474 } 4475 } 4476 4477 free_aligned((void *)tlsstart); 4478 free((void*) dtv); 4479} 4480 4481#endif 4482 4483/* 4484 * Allocate TLS block for module with given index. 4485 */ 4486void * 4487allocate_module_tls(int index) 4488{ 4489 Obj_Entry* obj; 4490 char* p; 4491 4492 for (obj = obj_list; obj; obj = obj->next) { 4493 if (obj->tlsindex == index) 4494 break; 4495 } 4496 if (!obj) { 4497 _rtld_error("Can't find module with TLS index %d", index); 4498 rtld_die(); 4499 } 4500 4501 p = malloc_aligned(obj->tlssize, obj->tlsalign); 4502 memcpy(p, obj->tlsinit, obj->tlsinitsize); 4503 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 4504 4505 return p; 4506} 4507 4508bool 4509allocate_tls_offset(Obj_Entry *obj) 4510{ 4511 size_t off; 4512 4513 if (obj->tls_done) 4514 return true; 4515 4516 if (obj->tlssize == 0) { 4517 obj->tls_done = true; 4518 return true; 4519 } 4520 4521 if (obj->tlsindex == 1) 4522 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 4523 else 4524 off = calculate_tls_offset(tls_last_offset, tls_last_size, 4525 obj->tlssize, obj->tlsalign); 4526 4527 /* 4528 * If we have already fixed the size of the static TLS block, we 4529 * must stay within that size. When allocating the static TLS, we 4530 * leave a small amount of space spare to be used for dynamically 4531 * loading modules which use static TLS. 4532 */ 4533 if (tls_static_space != 0) { 4534 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 4535 return false; 4536 } else if (obj->tlsalign > tls_static_max_align) { 4537 tls_static_max_align = obj->tlsalign; 4538 } 4539 4540 tls_last_offset = obj->tlsoffset = off; 4541 tls_last_size = obj->tlssize; 4542 obj->tls_done = true; 4543 4544 return true; 4545} 4546 4547void 4548free_tls_offset(Obj_Entry *obj) 4549{ 4550 4551 /* 4552 * If we were the last thing to allocate out of the static TLS 4553 * block, we give our space back to the 'allocator'. This is a 4554 * simplistic workaround to allow libGL.so.1 to be loaded and 4555 * unloaded multiple times. 4556 */ 4557 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 4558 == calculate_tls_end(tls_last_offset, tls_last_size)) { 4559 tls_last_offset -= obj->tlssize; 4560 tls_last_size = 0; 4561 } 4562} 4563 4564void * 4565_rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 4566{ 4567 void *ret; 4568 RtldLockState lockstate; 4569 4570 wlock_acquire(rtld_bind_lock, &lockstate); 4571 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign); 4572 lock_release(rtld_bind_lock, &lockstate); 4573 return (ret); 4574} 4575 4576void 4577_rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4578{ 4579 RtldLockState lockstate; 4580 4581 wlock_acquire(rtld_bind_lock, &lockstate); 4582 free_tls(tcb, tcbsize, tcbalign); 4583 lock_release(rtld_bind_lock, &lockstate); 4584} 4585 4586static void 4587object_add_name(Obj_Entry *obj, const char *name) 4588{ 4589 Name_Entry *entry; 4590 size_t len; 4591 4592 len = strlen(name); 4593 entry = malloc(sizeof(Name_Entry) + len); 4594 4595 if (entry != NULL) { 4596 strcpy(entry->name, name); 4597 STAILQ_INSERT_TAIL(&obj->names, entry, link); 4598 } 4599} 4600 4601static int 4602object_match_name(const Obj_Entry *obj, const char *name) 4603{ 4604 Name_Entry *entry; 4605 4606 STAILQ_FOREACH(entry, &obj->names, link) { 4607 if (strcmp(name, entry->name) == 0) 4608 return (1); 4609 } 4610 return (0); 4611} 4612 4613static Obj_Entry * 4614locate_dependency(const Obj_Entry *obj, const char *name) 4615{ 4616 const Objlist_Entry *entry; 4617 const Needed_Entry *needed; 4618 4619 STAILQ_FOREACH(entry, &list_main, link) { 4620 if (object_match_name(entry->obj, name)) 4621 return entry->obj; 4622 } 4623 4624 for (needed = obj->needed; needed != NULL; needed = needed->next) { 4625 if (strcmp(obj->strtab + needed->name, name) == 0 || 4626 (needed->obj != NULL && object_match_name(needed->obj, name))) { 4627 /* 4628 * If there is DT_NEEDED for the name we are looking for, 4629 * we are all set. Note that object might not be found if 4630 * dependency was not loaded yet, so the function can 4631 * return NULL here. This is expected and handled 4632 * properly by the caller. 4633 */ 4634 return (needed->obj); 4635 } 4636 } 4637 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 4638 obj->path, name); 4639 rtld_die(); 4640} 4641 4642static int 4643check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 4644 const Elf_Vernaux *vna) 4645{ 4646 const Elf_Verdef *vd; 4647 const char *vername; 4648 4649 vername = refobj->strtab + vna->vna_name; 4650 vd = depobj->verdef; 4651 if (vd == NULL) { 4652 _rtld_error("%s: version %s required by %s not defined", 4653 depobj->path, vername, refobj->path); 4654 return (-1); 4655 } 4656 for (;;) { 4657 if (vd->vd_version != VER_DEF_CURRENT) { 4658 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4659 depobj->path, vd->vd_version); 4660 return (-1); 4661 } 4662 if (vna->vna_hash == vd->vd_hash) { 4663 const Elf_Verdaux *aux = (const Elf_Verdaux *) 4664 ((char *)vd + vd->vd_aux); 4665 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 4666 return (0); 4667 } 4668 if (vd->vd_next == 0) 4669 break; 4670 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4671 } 4672 if (vna->vna_flags & VER_FLG_WEAK) 4673 return (0); 4674 _rtld_error("%s: version %s required by %s not found", 4675 depobj->path, vername, refobj->path); 4676 return (-1); 4677} 4678 4679static int 4680rtld_verify_object_versions(Obj_Entry *obj) 4681{ 4682 const Elf_Verneed *vn; 4683 const Elf_Verdef *vd; 4684 const Elf_Verdaux *vda; 4685 const Elf_Vernaux *vna; 4686 const Obj_Entry *depobj; 4687 int maxvernum, vernum; 4688 4689 if (obj->ver_checked) 4690 return (0); 4691 obj->ver_checked = true; 4692 4693 maxvernum = 0; 4694 /* 4695 * Walk over defined and required version records and figure out 4696 * max index used by any of them. Do very basic sanity checking 4697 * while there. 4698 */ 4699 vn = obj->verneed; 4700 while (vn != NULL) { 4701 if (vn->vn_version != VER_NEED_CURRENT) { 4702 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 4703 obj->path, vn->vn_version); 4704 return (-1); 4705 } 4706 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4707 for (;;) { 4708 vernum = VER_NEED_IDX(vna->vna_other); 4709 if (vernum > maxvernum) 4710 maxvernum = vernum; 4711 if (vna->vna_next == 0) 4712 break; 4713 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4714 } 4715 if (vn->vn_next == 0) 4716 break; 4717 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4718 } 4719 4720 vd = obj->verdef; 4721 while (vd != NULL) { 4722 if (vd->vd_version != VER_DEF_CURRENT) { 4723 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4724 obj->path, vd->vd_version); 4725 return (-1); 4726 } 4727 vernum = VER_DEF_IDX(vd->vd_ndx); 4728 if (vernum > maxvernum) 4729 maxvernum = vernum; 4730 if (vd->vd_next == 0) 4731 break; 4732 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4733 } 4734 4735 if (maxvernum == 0) 4736 return (0); 4737 4738 /* 4739 * Store version information in array indexable by version index. 4740 * Verify that object version requirements are satisfied along the 4741 * way. 4742 */ 4743 obj->vernum = maxvernum + 1; 4744 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 4745 4746 vd = obj->verdef; 4747 while (vd != NULL) { 4748 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 4749 vernum = VER_DEF_IDX(vd->vd_ndx); 4750 assert(vernum <= maxvernum); 4751 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 4752 obj->vertab[vernum].hash = vd->vd_hash; 4753 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 4754 obj->vertab[vernum].file = NULL; 4755 obj->vertab[vernum].flags = 0; 4756 } 4757 if (vd->vd_next == 0) 4758 break; 4759 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4760 } 4761 4762 vn = obj->verneed; 4763 while (vn != NULL) { 4764 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 4765 if (depobj == NULL) 4766 return (-1); 4767 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4768 for (;;) { 4769 if (check_object_provided_version(obj, depobj, vna)) 4770 return (-1); 4771 vernum = VER_NEED_IDX(vna->vna_other); 4772 assert(vernum <= maxvernum); 4773 obj->vertab[vernum].hash = vna->vna_hash; 4774 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 4775 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 4776 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 4777 VER_INFO_HIDDEN : 0; 4778 if (vna->vna_next == 0) 4779 break; 4780 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4781 } 4782 if (vn->vn_next == 0) 4783 break; 4784 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4785 } 4786 return 0; 4787} 4788 4789static int 4790rtld_verify_versions(const Objlist *objlist) 4791{ 4792 Objlist_Entry *entry; 4793 int rc; 4794 4795 rc = 0; 4796 STAILQ_FOREACH(entry, objlist, link) { 4797 /* 4798 * Skip dummy objects or objects that have their version requirements 4799 * already checked. 4800 */ 4801 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 4802 continue; 4803 if (rtld_verify_object_versions(entry->obj) == -1) { 4804 rc = -1; 4805 if (ld_tracing == NULL) 4806 break; 4807 } 4808 } 4809 if (rc == 0 || ld_tracing != NULL) 4810 rc = rtld_verify_object_versions(&obj_rtld); 4811 return rc; 4812} 4813 4814const Ver_Entry * 4815fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 4816{ 4817 Elf_Versym vernum; 4818 4819 if (obj->vertab) { 4820 vernum = VER_NDX(obj->versyms[symnum]); 4821 if (vernum >= obj->vernum) { 4822 _rtld_error("%s: symbol %s has wrong verneed value %d", 4823 obj->path, obj->strtab + symnum, vernum); 4824 } else if (obj->vertab[vernum].hash != 0) { 4825 return &obj->vertab[vernum]; 4826 } 4827 } 4828 return NULL; 4829} 4830 4831int 4832_rtld_get_stack_prot(void) 4833{ 4834 4835 return (stack_prot); 4836} 4837 4838int 4839_rtld_is_dlopened(void *arg) 4840{ 4841 Obj_Entry *obj; 4842 RtldLockState lockstate; 4843 int res; 4844 4845 rlock_acquire(rtld_bind_lock, &lockstate); 4846 obj = dlcheck(arg); 4847 if (obj == NULL) 4848 obj = obj_from_addr(arg); 4849 if (obj == NULL) { 4850 _rtld_error("No shared object contains address"); 4851 lock_release(rtld_bind_lock, &lockstate); 4852 return (-1); 4853 } 4854 res = obj->dlopened ? 1 : 0; 4855 lock_release(rtld_bind_lock, &lockstate); 4856 return (res); 4857} 4858 4859static void 4860map_stacks_exec(RtldLockState *lockstate) 4861{ 4862 void (*thr_map_stacks_exec)(void); 4863 4864 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 4865 return; 4866 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 4867 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 4868 if (thr_map_stacks_exec != NULL) { 4869 stack_prot |= PROT_EXEC; 4870 thr_map_stacks_exec(); 4871 } 4872} 4873 4874void 4875symlook_init(SymLook *dst, const char *name) 4876{ 4877 4878 bzero(dst, sizeof(*dst)); 4879 dst->name = name; 4880 dst->hash = elf_hash(name); 4881 dst->hash_gnu = gnu_hash(name); 4882} 4883 4884static void 4885symlook_init_from_req(SymLook *dst, const SymLook *src) 4886{ 4887 4888 dst->name = src->name; 4889 dst->hash = src->hash; 4890 dst->hash_gnu = src->hash_gnu; 4891 dst->ventry = src->ventry; 4892 dst->flags = src->flags; 4893 dst->defobj_out = NULL; 4894 dst->sym_out = NULL; 4895 dst->lockstate = src->lockstate; 4896} 4897 4898/* 4899 * Overrides for libc_pic-provided functions. 4900 */ 4901 4902int 4903__getosreldate(void) 4904{ 4905 size_t len; 4906 int oid[2]; 4907 int error, osrel; 4908 4909 if (osreldate != 0) 4910 return (osreldate); 4911 4912 oid[0] = CTL_KERN; 4913 oid[1] = KERN_OSRELDATE; 4914 osrel = 0; 4915 len = sizeof(osrel); 4916 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 4917 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 4918 osreldate = osrel; 4919 return (osreldate); 4920} 4921 4922void 4923exit(int status) 4924{ 4925 4926 _exit(status); 4927} 4928 4929void (*__cleanup)(void); 4930int __isthreaded = 0; 4931int _thread_autoinit_dummy_decl = 1; 4932 4933/* 4934 * No unresolved symbols for rtld. 4935 */ 4936void 4937__pthread_cxa_finalize(struct dl_phdr_info *a) 4938{ 4939} 4940 4941void 4942__stack_chk_fail(void) 4943{ 4944 4945 _rtld_error("stack overflow detected; terminated"); 4946 rtld_die(); 4947} 4948__weak_reference(__stack_chk_fail, __stack_chk_fail_local); 4949 4950void 4951__chk_fail(void) 4952{ 4953 4954 _rtld_error("buffer overflow detected; terminated"); 4955 rtld_die(); 4956} 4957 4958const char * 4959rtld_strerror(int errnum) 4960{ 4961 4962 if (errnum < 0 || errnum >= sys_nerr) 4963 return ("Unknown error"); 4964 return (sys_errlist[errnum]); 4965} 4966