rtld.c revision 293317
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 293317 2016-01-07 14:52:32Z emaste $ 29 */ 30 31/* 32 * Dynamic linker for ELF. 33 * 34 * John Polstra <jdp@polstra.com>. 35 */ 36 37#include <sys/param.h> 38#include <sys/mount.h> 39#include <sys/mman.h> 40#include <sys/stat.h> 41#include <sys/sysctl.h> 42#include <sys/uio.h> 43#include <sys/utsname.h> 44#include <sys/ktrace.h> 45 46#include <dlfcn.h> 47#include <err.h> 48#include <errno.h> 49#include <fcntl.h> 50#include <stdarg.h> 51#include <stdio.h> 52#include <stdlib.h> 53#include <string.h> 54#include <unistd.h> 55 56#include "debug.h" 57#include "rtld.h" 58#include "libmap.h" 59#include "rtld_tls.h" 60#include "rtld_printf.h" 61#include "notes.h" 62 63#ifndef COMPAT_32BIT 64#define PATH_RTLD "/libexec/ld-elf.so.1" 65#else 66#define PATH_RTLD "/libexec/ld-elf32.so.1" 67#endif 68 69/* Types. */ 70typedef void (*func_ptr_type)(); 71typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 72 73/* 74 * Function declarations. 75 */ 76static const char *basename(const char *); 77static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 78 const Elf_Dyn **, const Elf_Dyn **); 79static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *, 80 const Elf_Dyn *); 81static void digest_dynamic(Obj_Entry *, int); 82static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 83static Obj_Entry *dlcheck(void *); 84static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, 85 int lo_flags, int mode, RtldLockState *lockstate); 86static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 87static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 88static bool donelist_check(DoneList *, const Obj_Entry *); 89static void errmsg_restore(char *); 90static char *errmsg_save(void); 91static void *fill_search_info(const char *, size_t, void *); 92static char *find_library(const char *, const Obj_Entry *); 93static const char *gethints(bool); 94static void init_dag(Obj_Entry *); 95static void init_pagesizes(Elf_Auxinfo **aux_info); 96static void init_rtld(caddr_t, Elf_Auxinfo **); 97static void initlist_add_neededs(Needed_Entry *, Objlist *); 98static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *); 99static void linkmap_add(Obj_Entry *); 100static void linkmap_delete(Obj_Entry *); 101static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 102static void unload_filtees(Obj_Entry *); 103static int load_needed_objects(Obj_Entry *, int); 104static int load_preload_objects(void); 105static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 106static void map_stacks_exec(RtldLockState *); 107static Obj_Entry *obj_from_addr(const void *); 108static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 109static void objlist_call_init(Objlist *, RtldLockState *); 110static void objlist_clear(Objlist *); 111static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 112static void objlist_init(Objlist *); 113static void objlist_push_head(Objlist *, Obj_Entry *); 114static void objlist_push_tail(Objlist *, Obj_Entry *); 115static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 116static void objlist_remove(Objlist *, Obj_Entry *); 117static void *path_enumerate(const char *, path_enum_proc, void *); 118static int relocate_object_dag(Obj_Entry *root, bool bind_now, 119 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 120static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 121 int flags, RtldLockState *lockstate); 122static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 123 RtldLockState *); 124static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now, 125 int flags, RtldLockState *lockstate); 126static int rtld_dirname(const char *, char *); 127static int rtld_dirname_abs(const char *, char *); 128static void *rtld_dlopen(const char *name, int fd, int mode); 129static void rtld_exit(void); 130static char *search_library_path(const char *, const char *); 131static const void **get_program_var_addr(const char *, RtldLockState *); 132static void set_program_var(const char *, const void *); 133static int symlook_default(SymLook *, const Obj_Entry *refobj); 134static int symlook_global(SymLook *, DoneList *); 135static void symlook_init_from_req(SymLook *, const SymLook *); 136static int symlook_list(SymLook *, const Objlist *, DoneList *); 137static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 138static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 139static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 140static void trace_loaded_objects(Obj_Entry *); 141static void unlink_object(Obj_Entry *); 142static void unload_object(Obj_Entry *); 143static void unref_dag(Obj_Entry *); 144static void ref_dag(Obj_Entry *); 145static char *origin_subst_one(Obj_Entry *, char *, const char *, 146 const char *, bool); 147static char *origin_subst(Obj_Entry *, char *); 148static bool obj_resolve_origin(Obj_Entry *obj); 149static void preinit_main(void); 150static int rtld_verify_versions(const Objlist *); 151static int rtld_verify_object_versions(Obj_Entry *); 152static void object_add_name(Obj_Entry *, const char *); 153static int object_match_name(const Obj_Entry *, const char *); 154static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 155static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 156 struct dl_phdr_info *phdr_info); 157static uint32_t gnu_hash(const char *); 158static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 159 const unsigned long); 160 161void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported; 162void _r_debug_postinit(struct link_map *) __noinline __exported; 163 164/* 165 * Data declarations. 166 */ 167static char *error_message; /* Message for dlerror(), or NULL */ 168struct r_debug r_debug __exported; /* for GDB; */ 169static bool libmap_disable; /* Disable libmap */ 170static bool ld_loadfltr; /* Immediate filters processing */ 171static char *libmap_override; /* Maps to use in addition to libmap.conf */ 172static bool trust; /* False for setuid and setgid programs */ 173static bool dangerous_ld_env; /* True if environment variables have been 174 used to affect the libraries loaded */ 175static char *ld_bind_now; /* Environment variable for immediate binding */ 176static char *ld_debug; /* Environment variable for debugging */ 177static char *ld_library_path; /* Environment variable for search path */ 178static char *ld_preload; /* Environment variable for libraries to 179 load first */ 180static char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 181static char *ld_tracing; /* Called from ldd to print libs */ 182static char *ld_utrace; /* Use utrace() to log events. */ 183static Obj_Entry *obj_list; /* Head of linked list of shared objects */ 184static Obj_Entry **obj_tail; /* Link field of last object in list */ 185static Obj_Entry *obj_main; /* The main program shared object */ 186static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 187static unsigned int obj_count; /* Number of objects in obj_list */ 188static unsigned int obj_loads; /* Number of objects in obj_list */ 189 190static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 191 STAILQ_HEAD_INITIALIZER(list_global); 192static Objlist list_main = /* Objects loaded at program startup */ 193 STAILQ_HEAD_INITIALIZER(list_main); 194static Objlist list_fini = /* Objects needing fini() calls */ 195 STAILQ_HEAD_INITIALIZER(list_fini); 196 197Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 198 199#define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 200 201extern Elf_Dyn _DYNAMIC; 202#pragma weak _DYNAMIC 203#ifndef RTLD_IS_DYNAMIC 204#define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL) 205#endif 206 207int dlclose(void *) __exported; 208char *dlerror(void) __exported; 209void *dlopen(const char *, int) __exported; 210void *fdlopen(int, int) __exported; 211void *dlsym(void *, const char *) __exported; 212dlfunc_t dlfunc(void *, const char *) __exported; 213void *dlvsym(void *, const char *, const char *) __exported; 214int dladdr(const void *, Dl_info *) __exported; 215void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *), 216 void (*)(void *), void (*)(void *), void (*)(void *)) __exported; 217int dlinfo(void *, int , void *) __exported; 218int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported; 219int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported; 220int _rtld_get_stack_prot(void) __exported; 221int _rtld_is_dlopened(void *) __exported; 222void _rtld_error(const char *, ...) __exported; 223 224int npagesizes, osreldate; 225size_t *pagesizes; 226 227long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0}; 228 229static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 230static int max_stack_flags; 231 232/* 233 * Global declarations normally provided by crt1. The dynamic linker is 234 * not built with crt1, so we have to provide them ourselves. 235 */ 236char *__progname; 237char **environ; 238 239/* 240 * Used to pass argc, argv to init functions. 241 */ 242int main_argc; 243char **main_argv; 244 245/* 246 * Globals to control TLS allocation. 247 */ 248size_t tls_last_offset; /* Static TLS offset of last module */ 249size_t tls_last_size; /* Static TLS size of last module */ 250size_t tls_static_space; /* Static TLS space allocated */ 251size_t tls_static_max_align; 252int tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 253int tls_max_index = 1; /* Largest module index allocated */ 254 255bool ld_library_path_rpath = false; 256 257/* 258 * Fill in a DoneList with an allocation large enough to hold all of 259 * the currently-loaded objects. Keep this as a macro since it calls 260 * alloca and we want that to occur within the scope of the caller. 261 */ 262#define donelist_init(dlp) \ 263 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 264 assert((dlp)->objs != NULL), \ 265 (dlp)->num_alloc = obj_count, \ 266 (dlp)->num_used = 0) 267 268#define UTRACE_DLOPEN_START 1 269#define UTRACE_DLOPEN_STOP 2 270#define UTRACE_DLCLOSE_START 3 271#define UTRACE_DLCLOSE_STOP 4 272#define UTRACE_LOAD_OBJECT 5 273#define UTRACE_UNLOAD_OBJECT 6 274#define UTRACE_ADD_RUNDEP 7 275#define UTRACE_PRELOAD_FINISHED 8 276#define UTRACE_INIT_CALL 9 277#define UTRACE_FINI_CALL 10 278#define UTRACE_DLSYM_START 11 279#define UTRACE_DLSYM_STOP 12 280 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(Obj_Entry *obj, char *real, const char *kw, 783 const char *subst, 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 * Return non-substituted string if resolution failed. We 804 * cannot do anything more reasonable, the failure mode of the 805 * caller is unresolved library anyway. 806 */ 807 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj))) 808 return (may_free ? real : xstrdup(real)); 809 if (obj != NULL) 810 subst = obj->origin_path; 811 812 /* 813 * There is indeed something to substitute. Calculate the 814 * length of the resulting string, and allocate it. 815 */ 816 subst_len = strlen(subst); 817 old_len = strlen(real); 818 new_len = old_len + (subst_len - kw_len) * subst_count; 819 res = xmalloc(new_len + 1); 820 821 /* 822 * Now, execute the substitution loop. 823 */ 824 for (p = real, resp = res, *resp = '\0';;) { 825 p1 = strstr(p, kw); 826 if (p1 != NULL) { 827 /* Copy the prefix before keyword. */ 828 memcpy(resp, p, p1 - p); 829 resp += p1 - p; 830 /* Keyword replacement. */ 831 memcpy(resp, subst, subst_len); 832 resp += subst_len; 833 *resp = '\0'; 834 p = p1 + kw_len; 835 } else 836 break; 837 } 838 839 /* Copy to the end of string and finish. */ 840 strcat(resp, p); 841 if (may_free) 842 free(real); 843 return (res); 844} 845 846static char * 847origin_subst(Obj_Entry *obj, char *real) 848{ 849 char *res1, *res2, *res3, *res4; 850 851 if (obj == NULL || !trust) 852 return (xstrdup(real)); 853 if (uts.sysname[0] == '\0') { 854 if (uname(&uts) != 0) { 855 _rtld_error("utsname failed: %d", errno); 856 return (NULL); 857 } 858 } 859 res1 = origin_subst_one(obj, real, "$ORIGIN", NULL, false); 860 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true); 861 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true); 862 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true); 863 return (res4); 864} 865 866void 867rtld_die(void) 868{ 869 const char *msg = dlerror(); 870 871 if (msg == NULL) 872 msg = "Fatal error"; 873 rtld_fdputstr(STDERR_FILENO, msg); 874 rtld_fdputchar(STDERR_FILENO, '\n'); 875 _exit(1); 876} 877 878/* 879 * Process a shared object's DYNAMIC section, and save the important 880 * information in its Obj_Entry structure. 881 */ 882static void 883digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 884 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 885{ 886 const Elf_Dyn *dynp; 887 Needed_Entry **needed_tail = &obj->needed; 888 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 889 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 890 const Elf_Hashelt *hashtab; 891 const Elf32_Word *hashval; 892 Elf32_Word bkt, nmaskwords; 893 int bloom_size32; 894 int plttype = DT_REL; 895 896 *dyn_rpath = NULL; 897 *dyn_soname = NULL; 898 *dyn_runpath = NULL; 899 900 obj->bind_now = false; 901 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 902 switch (dynp->d_tag) { 903 904 case DT_REL: 905 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 906 break; 907 908 case DT_RELSZ: 909 obj->relsize = dynp->d_un.d_val; 910 break; 911 912 case DT_RELENT: 913 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 914 break; 915 916 case DT_JMPREL: 917 obj->pltrel = (const Elf_Rel *) 918 (obj->relocbase + dynp->d_un.d_ptr); 919 break; 920 921 case DT_PLTRELSZ: 922 obj->pltrelsize = dynp->d_un.d_val; 923 break; 924 925 case DT_RELA: 926 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 927 break; 928 929 case DT_RELASZ: 930 obj->relasize = dynp->d_un.d_val; 931 break; 932 933 case DT_RELAENT: 934 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 935 break; 936 937 case DT_PLTREL: 938 plttype = dynp->d_un.d_val; 939 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 940 break; 941 942 case DT_SYMTAB: 943 obj->symtab = (const Elf_Sym *) 944 (obj->relocbase + dynp->d_un.d_ptr); 945 break; 946 947 case DT_SYMENT: 948 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 949 break; 950 951 case DT_STRTAB: 952 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 953 break; 954 955 case DT_STRSZ: 956 obj->strsize = dynp->d_un.d_val; 957 break; 958 959 case DT_VERNEED: 960 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 961 dynp->d_un.d_val); 962 break; 963 964 case DT_VERNEEDNUM: 965 obj->verneednum = dynp->d_un.d_val; 966 break; 967 968 case DT_VERDEF: 969 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 970 dynp->d_un.d_val); 971 break; 972 973 case DT_VERDEFNUM: 974 obj->verdefnum = dynp->d_un.d_val; 975 break; 976 977 case DT_VERSYM: 978 obj->versyms = (const Elf_Versym *)(obj->relocbase + 979 dynp->d_un.d_val); 980 break; 981 982 case DT_HASH: 983 { 984 hashtab = (const Elf_Hashelt *)(obj->relocbase + 985 dynp->d_un.d_ptr); 986 obj->nbuckets = hashtab[0]; 987 obj->nchains = hashtab[1]; 988 obj->buckets = hashtab + 2; 989 obj->chains = obj->buckets + obj->nbuckets; 990 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 991 obj->buckets != NULL; 992 } 993 break; 994 995 case DT_GNU_HASH: 996 { 997 hashtab = (const Elf_Hashelt *)(obj->relocbase + 998 dynp->d_un.d_ptr); 999 obj->nbuckets_gnu = hashtab[0]; 1000 obj->symndx_gnu = hashtab[1]; 1001 nmaskwords = hashtab[2]; 1002 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1003 obj->maskwords_bm_gnu = nmaskwords - 1; 1004 obj->shift2_gnu = hashtab[3]; 1005 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4); 1006 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1007 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1008 obj->symndx_gnu; 1009 /* Number of bitmask words is required to be power of 2 */ 1010 obj->valid_hash_gnu = powerof2(nmaskwords) && 1011 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1012 } 1013 break; 1014 1015 case DT_NEEDED: 1016 if (!obj->rtld) { 1017 Needed_Entry *nep = NEW(Needed_Entry); 1018 nep->name = dynp->d_un.d_val; 1019 nep->obj = NULL; 1020 nep->next = NULL; 1021 1022 *needed_tail = nep; 1023 needed_tail = &nep->next; 1024 } 1025 break; 1026 1027 case DT_FILTER: 1028 if (!obj->rtld) { 1029 Needed_Entry *nep = NEW(Needed_Entry); 1030 nep->name = dynp->d_un.d_val; 1031 nep->obj = NULL; 1032 nep->next = NULL; 1033 1034 *needed_filtees_tail = nep; 1035 needed_filtees_tail = &nep->next; 1036 } 1037 break; 1038 1039 case DT_AUXILIARY: 1040 if (!obj->rtld) { 1041 Needed_Entry *nep = NEW(Needed_Entry); 1042 nep->name = dynp->d_un.d_val; 1043 nep->obj = NULL; 1044 nep->next = NULL; 1045 1046 *needed_aux_filtees_tail = nep; 1047 needed_aux_filtees_tail = &nep->next; 1048 } 1049 break; 1050 1051 case DT_PLTGOT: 1052 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 1053 break; 1054 1055 case DT_TEXTREL: 1056 obj->textrel = true; 1057 break; 1058 1059 case DT_SYMBOLIC: 1060 obj->symbolic = true; 1061 break; 1062 1063 case DT_RPATH: 1064 /* 1065 * We have to wait until later to process this, because we 1066 * might not have gotten the address of the string table yet. 1067 */ 1068 *dyn_rpath = dynp; 1069 break; 1070 1071 case DT_SONAME: 1072 *dyn_soname = dynp; 1073 break; 1074 1075 case DT_RUNPATH: 1076 *dyn_runpath = dynp; 1077 break; 1078 1079 case DT_INIT: 1080 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1081 break; 1082 1083 case DT_PREINIT_ARRAY: 1084 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1085 break; 1086 1087 case DT_PREINIT_ARRAYSZ: 1088 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1089 break; 1090 1091 case DT_INIT_ARRAY: 1092 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1093 break; 1094 1095 case DT_INIT_ARRAYSZ: 1096 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1097 break; 1098 1099 case DT_FINI: 1100 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1101 break; 1102 1103 case DT_FINI_ARRAY: 1104 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1105 break; 1106 1107 case DT_FINI_ARRAYSZ: 1108 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1109 break; 1110 1111 /* 1112 * Don't process DT_DEBUG on MIPS as the dynamic section 1113 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1114 */ 1115 1116#ifndef __mips__ 1117 case DT_DEBUG: 1118 if (!early) 1119 dbg("Filling in DT_DEBUG entry"); 1120 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 1121 break; 1122#endif 1123 1124 case DT_FLAGS: 1125 if (dynp->d_un.d_val & DF_ORIGIN) 1126 obj->z_origin = true; 1127 if (dynp->d_un.d_val & DF_SYMBOLIC) 1128 obj->symbolic = true; 1129 if (dynp->d_un.d_val & DF_TEXTREL) 1130 obj->textrel = true; 1131 if (dynp->d_un.d_val & DF_BIND_NOW) 1132 obj->bind_now = true; 1133 /*if (dynp->d_un.d_val & DF_STATIC_TLS) 1134 ;*/ 1135 break; 1136#ifdef __mips__ 1137 case DT_MIPS_LOCAL_GOTNO: 1138 obj->local_gotno = dynp->d_un.d_val; 1139 break; 1140 1141 case DT_MIPS_SYMTABNO: 1142 obj->symtabno = dynp->d_un.d_val; 1143 break; 1144 1145 case DT_MIPS_GOTSYM: 1146 obj->gotsym = dynp->d_un.d_val; 1147 break; 1148 1149 case DT_MIPS_RLD_MAP: 1150 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1151 break; 1152#endif 1153 1154 case DT_FLAGS_1: 1155 if (dynp->d_un.d_val & DF_1_NOOPEN) 1156 obj->z_noopen = true; 1157 if (dynp->d_un.d_val & DF_1_ORIGIN) 1158 obj->z_origin = true; 1159 if (dynp->d_un.d_val & DF_1_GLOBAL) 1160 obj->z_global = true; 1161 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1162 obj->bind_now = true; 1163 if (dynp->d_un.d_val & DF_1_NODELETE) 1164 obj->z_nodelete = true; 1165 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1166 obj->z_loadfltr = true; 1167 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1168 obj->z_interpose = true; 1169 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1170 obj->z_nodeflib = true; 1171 break; 1172 1173 default: 1174 if (!early) { 1175 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1176 (long)dynp->d_tag); 1177 } 1178 break; 1179 } 1180 } 1181 1182 obj->traced = false; 1183 1184 if (plttype == DT_RELA) { 1185 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1186 obj->pltrel = NULL; 1187 obj->pltrelasize = obj->pltrelsize; 1188 obj->pltrelsize = 0; 1189 } 1190 1191 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1192 if (obj->valid_hash_sysv) 1193 obj->dynsymcount = obj->nchains; 1194 else if (obj->valid_hash_gnu) { 1195 obj->dynsymcount = 0; 1196 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1197 if (obj->buckets_gnu[bkt] == 0) 1198 continue; 1199 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1200 do 1201 obj->dynsymcount++; 1202 while ((*hashval++ & 1u) == 0); 1203 } 1204 obj->dynsymcount += obj->symndx_gnu; 1205 } 1206} 1207 1208static bool 1209obj_resolve_origin(Obj_Entry *obj) 1210{ 1211 1212 if (obj->origin_path != NULL) 1213 return (true); 1214 obj->origin_path = xmalloc(PATH_MAX); 1215 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1); 1216} 1217 1218static void 1219digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1220 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1221{ 1222 1223 if (obj->z_origin && !obj_resolve_origin(obj)) 1224 rtld_die(); 1225 1226 if (dyn_runpath != NULL) { 1227 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val; 1228 obj->runpath = origin_subst(obj, obj->runpath); 1229 } else if (dyn_rpath != NULL) { 1230 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 1231 obj->rpath = origin_subst(obj, obj->rpath); 1232 } 1233 if (dyn_soname != NULL) 1234 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1235} 1236 1237static void 1238digest_dynamic(Obj_Entry *obj, int early) 1239{ 1240 const Elf_Dyn *dyn_rpath; 1241 const Elf_Dyn *dyn_soname; 1242 const Elf_Dyn *dyn_runpath; 1243 1244 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1245 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath); 1246} 1247 1248/* 1249 * Process a shared object's program header. This is used only for the 1250 * main program, when the kernel has already loaded the main program 1251 * into memory before calling the dynamic linker. It creates and 1252 * returns an Obj_Entry structure. 1253 */ 1254static Obj_Entry * 1255digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1256{ 1257 Obj_Entry *obj; 1258 const Elf_Phdr *phlimit = phdr + phnum; 1259 const Elf_Phdr *ph; 1260 Elf_Addr note_start, note_end; 1261 int nsegs = 0; 1262 1263 obj = obj_new(); 1264 for (ph = phdr; ph < phlimit; ph++) { 1265 if (ph->p_type != PT_PHDR) 1266 continue; 1267 1268 obj->phdr = phdr; 1269 obj->phsize = ph->p_memsz; 1270 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1271 break; 1272 } 1273 1274 obj->stack_flags = PF_X | PF_R | PF_W; 1275 1276 for (ph = phdr; ph < phlimit; ph++) { 1277 switch (ph->p_type) { 1278 1279 case PT_INTERP: 1280 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1281 break; 1282 1283 case PT_LOAD: 1284 if (nsegs == 0) { /* First load segment */ 1285 obj->vaddrbase = trunc_page(ph->p_vaddr); 1286 obj->mapbase = obj->vaddrbase + obj->relocbase; 1287 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1288 obj->vaddrbase; 1289 } else { /* Last load segment */ 1290 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1291 obj->vaddrbase; 1292 } 1293 nsegs++; 1294 break; 1295 1296 case PT_DYNAMIC: 1297 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1298 break; 1299 1300 case PT_TLS: 1301 obj->tlsindex = 1; 1302 obj->tlssize = ph->p_memsz; 1303 obj->tlsalign = ph->p_align; 1304 obj->tlsinitsize = ph->p_filesz; 1305 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1306 break; 1307 1308 case PT_GNU_STACK: 1309 obj->stack_flags = ph->p_flags; 1310 break; 1311 1312 case PT_GNU_RELRO: 1313 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1314 obj->relro_size = round_page(ph->p_memsz); 1315 break; 1316 1317 case PT_NOTE: 1318 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1319 note_end = note_start + ph->p_filesz; 1320 digest_notes(obj, note_start, note_end); 1321 break; 1322 } 1323 } 1324 if (nsegs < 1) { 1325 _rtld_error("%s: too few PT_LOAD segments", path); 1326 return NULL; 1327 } 1328 1329 obj->entry = entry; 1330 return obj; 1331} 1332 1333void 1334digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1335{ 1336 const Elf_Note *note; 1337 const char *note_name; 1338 uintptr_t p; 1339 1340 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1341 note = (const Elf_Note *)((const char *)(note + 1) + 1342 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1343 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1344 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1345 note->n_descsz != sizeof(int32_t)) 1346 continue; 1347 if (note->n_type != ABI_NOTETYPE && 1348 note->n_type != CRT_NOINIT_NOTETYPE) 1349 continue; 1350 note_name = (const char *)(note + 1); 1351 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1352 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1353 continue; 1354 switch (note->n_type) { 1355 case ABI_NOTETYPE: 1356 /* FreeBSD osrel note */ 1357 p = (uintptr_t)(note + 1); 1358 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1359 obj->osrel = *(const int32_t *)(p); 1360 dbg("note osrel %d", obj->osrel); 1361 break; 1362 case CRT_NOINIT_NOTETYPE: 1363 /* FreeBSD 'crt does not call init' note */ 1364 obj->crt_no_init = true; 1365 dbg("note crt_no_init"); 1366 break; 1367 } 1368 } 1369} 1370 1371static Obj_Entry * 1372dlcheck(void *handle) 1373{ 1374 Obj_Entry *obj; 1375 1376 for (obj = obj_list; obj != NULL; obj = obj->next) 1377 if (obj == (Obj_Entry *) handle) 1378 break; 1379 1380 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1381 _rtld_error("Invalid shared object handle %p", handle); 1382 return NULL; 1383 } 1384 return obj; 1385} 1386 1387/* 1388 * If the given object is already in the donelist, return true. Otherwise 1389 * add the object to the list and return false. 1390 */ 1391static bool 1392donelist_check(DoneList *dlp, const Obj_Entry *obj) 1393{ 1394 unsigned int i; 1395 1396 for (i = 0; i < dlp->num_used; i++) 1397 if (dlp->objs[i] == obj) 1398 return true; 1399 /* 1400 * Our donelist allocation should always be sufficient. But if 1401 * our threads locking isn't working properly, more shared objects 1402 * could have been loaded since we allocated the list. That should 1403 * never happen, but we'll handle it properly just in case it does. 1404 */ 1405 if (dlp->num_used < dlp->num_alloc) 1406 dlp->objs[dlp->num_used++] = obj; 1407 return false; 1408} 1409 1410/* 1411 * Hash function for symbol table lookup. Don't even think about changing 1412 * this. It is specified by the System V ABI. 1413 */ 1414unsigned long 1415elf_hash(const char *name) 1416{ 1417 const unsigned char *p = (const unsigned char *) name; 1418 unsigned long h = 0; 1419 unsigned long g; 1420 1421 while (*p != '\0') { 1422 h = (h << 4) + *p++; 1423 if ((g = h & 0xf0000000) != 0) 1424 h ^= g >> 24; 1425 h &= ~g; 1426 } 1427 return h; 1428} 1429 1430/* 1431 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1432 * unsigned in case it's implemented with a wider type. 1433 */ 1434static uint32_t 1435gnu_hash(const char *s) 1436{ 1437 uint32_t h; 1438 unsigned char c; 1439 1440 h = 5381; 1441 for (c = *s; c != '\0'; c = *++s) 1442 h = h * 33 + c; 1443 return (h & 0xffffffff); 1444} 1445 1446/* 1447 * Find the library with the given name, and return its full pathname. 1448 * The returned string is dynamically allocated. Generates an error 1449 * message and returns NULL if the library cannot be found. 1450 * 1451 * If the second argument is non-NULL, then it refers to an already- 1452 * loaded shared object, whose library search path will be searched. 1453 * 1454 * The search order is: 1455 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1456 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1457 * LD_LIBRARY_PATH 1458 * DT_RUNPATH in the referencing file 1459 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1460 * from list) 1461 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1462 * 1463 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1464 */ 1465static char * 1466find_library(const char *xname, const Obj_Entry *refobj) 1467{ 1468 char *pathname; 1469 char *name; 1470 bool nodeflib, objgiven; 1471 1472 objgiven = refobj != NULL; 1473 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */ 1474 if (xname[0] != '/' && !trust) { 1475 _rtld_error("Absolute pathname required for shared object \"%s\"", 1476 xname); 1477 return NULL; 1478 } 1479 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1480 __DECONST(char *, xname))); 1481 } 1482 1483 if (libmap_disable || !objgiven || 1484 (name = lm_find(refobj->path, xname)) == NULL) 1485 name = (char *)xname; 1486 1487 dbg(" Searching for \"%s\"", name); 1488 1489 /* 1490 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1491 * back to pre-conforming behaviour if user requested so with 1492 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1493 * nodeflib. 1494 */ 1495 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1496 if ((pathname = search_library_path(name, ld_library_path)) != NULL || 1497 (refobj != NULL && 1498 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1499 (pathname = search_library_path(name, gethints(false))) != NULL || 1500 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL) 1501 return (pathname); 1502 } else { 1503 nodeflib = objgiven ? refobj->z_nodeflib : false; 1504 if ((objgiven && 1505 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1506 (objgiven && refobj->runpath == NULL && refobj != obj_main && 1507 (pathname = search_library_path(name, obj_main->rpath)) != NULL) || 1508 (pathname = search_library_path(name, ld_library_path)) != NULL || 1509 (objgiven && 1510 (pathname = search_library_path(name, refobj->runpath)) != NULL) || 1511 (pathname = search_library_path(name, gethints(nodeflib))) != NULL || 1512 (objgiven && !nodeflib && 1513 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)) 1514 return (pathname); 1515 } 1516 1517 if (objgiven && refobj->path != NULL) { 1518 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 1519 name, basename(refobj->path)); 1520 } else { 1521 _rtld_error("Shared object \"%s\" not found", name); 1522 } 1523 return NULL; 1524} 1525 1526/* 1527 * Given a symbol number in a referencing object, find the corresponding 1528 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1529 * no definition was found. Returns a pointer to the Obj_Entry of the 1530 * defining object via the reference parameter DEFOBJ_OUT. 1531 */ 1532const Elf_Sym * 1533find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1534 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1535 RtldLockState *lockstate) 1536{ 1537 const Elf_Sym *ref; 1538 const Elf_Sym *def; 1539 const Obj_Entry *defobj; 1540 SymLook req; 1541 const char *name; 1542 int res; 1543 1544 /* 1545 * If we have already found this symbol, get the information from 1546 * the cache. 1547 */ 1548 if (symnum >= refobj->dynsymcount) 1549 return NULL; /* Bad object */ 1550 if (cache != NULL && cache[symnum].sym != NULL) { 1551 *defobj_out = cache[symnum].obj; 1552 return cache[symnum].sym; 1553 } 1554 1555 ref = refobj->symtab + symnum; 1556 name = refobj->strtab + ref->st_name; 1557 def = NULL; 1558 defobj = NULL; 1559 1560 /* 1561 * We don't have to do a full scale lookup if the symbol is local. 1562 * We know it will bind to the instance in this load module; to 1563 * which we already have a pointer (ie ref). By not doing a lookup, 1564 * we not only improve performance, but it also avoids unresolvable 1565 * symbols when local symbols are not in the hash table. This has 1566 * been seen with the ia64 toolchain. 1567 */ 1568 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1569 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1570 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1571 symnum); 1572 } 1573 symlook_init(&req, name); 1574 req.flags = flags; 1575 req.ventry = fetch_ventry(refobj, symnum); 1576 req.lockstate = lockstate; 1577 res = symlook_default(&req, refobj); 1578 if (res == 0) { 1579 def = req.sym_out; 1580 defobj = req.defobj_out; 1581 } 1582 } else { 1583 def = ref; 1584 defobj = refobj; 1585 } 1586 1587 /* 1588 * If we found no definition and the reference is weak, treat the 1589 * symbol as having the value zero. 1590 */ 1591 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1592 def = &sym_zero; 1593 defobj = obj_main; 1594 } 1595 1596 if (def != NULL) { 1597 *defobj_out = defobj; 1598 /* Record the information in the cache to avoid subsequent lookups. */ 1599 if (cache != NULL) { 1600 cache[symnum].sym = def; 1601 cache[symnum].obj = defobj; 1602 } 1603 } else { 1604 if (refobj != &obj_rtld) 1605 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name); 1606 } 1607 return def; 1608} 1609 1610/* 1611 * Return the search path from the ldconfig hints file, reading it if 1612 * necessary. If nostdlib is true, then the default search paths are 1613 * not added to result. 1614 * 1615 * Returns NULL if there are problems with the hints file, 1616 * or if the search path there is empty. 1617 */ 1618static const char * 1619gethints(bool nostdlib) 1620{ 1621 static char *hints, *filtered_path; 1622 struct elfhints_hdr hdr; 1623 struct fill_search_info_args sargs, hargs; 1624 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1625 struct dl_serpath *SLPpath, *hintpath; 1626 char *p; 1627 unsigned int SLPndx, hintndx, fndx, fcount; 1628 int fd; 1629 size_t flen; 1630 bool skip; 1631 1632 /* First call, read the hints file */ 1633 if (hints == NULL) { 1634 /* Keep from trying again in case the hints file is bad. */ 1635 hints = ""; 1636 1637 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1638 return (NULL); 1639 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1640 hdr.magic != ELFHINTS_MAGIC || 1641 hdr.version != 1) { 1642 close(fd); 1643 return (NULL); 1644 } 1645 p = xmalloc(hdr.dirlistlen + 1); 1646 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1647 read(fd, p, hdr.dirlistlen + 1) != 1648 (ssize_t)hdr.dirlistlen + 1) { 1649 free(p); 1650 close(fd); 1651 return (NULL); 1652 } 1653 hints = p; 1654 close(fd); 1655 } 1656 1657 /* 1658 * If caller agreed to receive list which includes the default 1659 * paths, we are done. Otherwise, if we still did not 1660 * calculated filtered result, do it now. 1661 */ 1662 if (!nostdlib) 1663 return (hints[0] != '\0' ? hints : NULL); 1664 if (filtered_path != NULL) 1665 goto filt_ret; 1666 1667 /* 1668 * Obtain the list of all configured search paths, and the 1669 * list of the default paths. 1670 * 1671 * First estimate the size of the results. 1672 */ 1673 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1674 smeta.dls_cnt = 0; 1675 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1676 hmeta.dls_cnt = 0; 1677 1678 sargs.request = RTLD_DI_SERINFOSIZE; 1679 sargs.serinfo = &smeta; 1680 hargs.request = RTLD_DI_SERINFOSIZE; 1681 hargs.serinfo = &hmeta; 1682 1683 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1684 path_enumerate(p, fill_search_info, &hargs); 1685 1686 SLPinfo = xmalloc(smeta.dls_size); 1687 hintinfo = xmalloc(hmeta.dls_size); 1688 1689 /* 1690 * Next fetch both sets of paths. 1691 */ 1692 sargs.request = RTLD_DI_SERINFO; 1693 sargs.serinfo = SLPinfo; 1694 sargs.serpath = &SLPinfo->dls_serpath[0]; 1695 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1696 1697 hargs.request = RTLD_DI_SERINFO; 1698 hargs.serinfo = hintinfo; 1699 hargs.serpath = &hintinfo->dls_serpath[0]; 1700 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1701 1702 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1703 path_enumerate(p, fill_search_info, &hargs); 1704 1705 /* 1706 * Now calculate the difference between two sets, by excluding 1707 * standard paths from the full set. 1708 */ 1709 fndx = 0; 1710 fcount = 0; 1711 filtered_path = xmalloc(hdr.dirlistlen + 1); 1712 hintpath = &hintinfo->dls_serpath[0]; 1713 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1714 skip = false; 1715 SLPpath = &SLPinfo->dls_serpath[0]; 1716 /* 1717 * Check each standard path against current. 1718 */ 1719 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1720 /* matched, skip the path */ 1721 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1722 skip = true; 1723 break; 1724 } 1725 } 1726 if (skip) 1727 continue; 1728 /* 1729 * Not matched against any standard path, add the path 1730 * to result. Separate consequtive paths with ':'. 1731 */ 1732 if (fcount > 0) { 1733 filtered_path[fndx] = ':'; 1734 fndx++; 1735 } 1736 fcount++; 1737 flen = strlen(hintpath->dls_name); 1738 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1739 fndx += flen; 1740 } 1741 filtered_path[fndx] = '\0'; 1742 1743 free(SLPinfo); 1744 free(hintinfo); 1745 1746filt_ret: 1747 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1748} 1749 1750static void 1751init_dag(Obj_Entry *root) 1752{ 1753 const Needed_Entry *needed; 1754 const Objlist_Entry *elm; 1755 DoneList donelist; 1756 1757 if (root->dag_inited) 1758 return; 1759 donelist_init(&donelist); 1760 1761 /* Root object belongs to own DAG. */ 1762 objlist_push_tail(&root->dldags, root); 1763 objlist_push_tail(&root->dagmembers, root); 1764 donelist_check(&donelist, root); 1765 1766 /* 1767 * Add dependencies of root object to DAG in breadth order 1768 * by exploiting the fact that each new object get added 1769 * to the tail of the dagmembers list. 1770 */ 1771 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1772 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1773 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1774 continue; 1775 objlist_push_tail(&needed->obj->dldags, root); 1776 objlist_push_tail(&root->dagmembers, needed->obj); 1777 } 1778 } 1779 root->dag_inited = true; 1780} 1781 1782static void 1783process_z(Obj_Entry *root) 1784{ 1785 const Objlist_Entry *elm; 1786 Obj_Entry *obj; 1787 1788 /* 1789 * Walk over object DAG and process every dependent object 1790 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 1791 * to grow their own DAG. 1792 * 1793 * For DF_1_GLOBAL, DAG is required for symbol lookups in 1794 * symlook_global() to work. 1795 * 1796 * For DF_1_NODELETE, the DAG should have its reference upped. 1797 */ 1798 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1799 obj = elm->obj; 1800 if (obj == NULL) 1801 continue; 1802 if (obj->z_nodelete && !obj->ref_nodel) { 1803 dbg("obj %s -z nodelete", obj->path); 1804 init_dag(obj); 1805 ref_dag(obj); 1806 obj->ref_nodel = true; 1807 } 1808 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 1809 dbg("obj %s -z global", obj->path); 1810 objlist_push_tail(&list_global, obj); 1811 init_dag(obj); 1812 } 1813 } 1814} 1815/* 1816 * Initialize the dynamic linker. The argument is the address at which 1817 * the dynamic linker has been mapped into memory. The primary task of 1818 * this function is to relocate the dynamic linker. 1819 */ 1820static void 1821init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 1822{ 1823 Obj_Entry objtmp; /* Temporary rtld object */ 1824 const Elf_Dyn *dyn_rpath; 1825 const Elf_Dyn *dyn_soname; 1826 const Elf_Dyn *dyn_runpath; 1827 1828#ifdef RTLD_INIT_PAGESIZES_EARLY 1829 /* The page size is required by the dynamic memory allocator. */ 1830 init_pagesizes(aux_info); 1831#endif 1832 1833 /* 1834 * Conjure up an Obj_Entry structure for the dynamic linker. 1835 * 1836 * The "path" member can't be initialized yet because string constants 1837 * cannot yet be accessed. Below we will set it correctly. 1838 */ 1839 memset(&objtmp, 0, sizeof(objtmp)); 1840 objtmp.path = NULL; 1841 objtmp.rtld = true; 1842 objtmp.mapbase = mapbase; 1843#ifdef PIC 1844 objtmp.relocbase = mapbase; 1845#endif 1846 if (RTLD_IS_DYNAMIC()) { 1847 objtmp.dynamic = rtld_dynamic(&objtmp); 1848 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 1849 assert(objtmp.needed == NULL); 1850#if !defined(__mips__) 1851 /* MIPS has a bogus DT_TEXTREL. */ 1852 assert(!objtmp.textrel); 1853#endif 1854 1855 /* 1856 * Temporarily put the dynamic linker entry into the object list, so 1857 * that symbols can be found. 1858 */ 1859 1860 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 1861 } 1862 1863 /* Initialize the object list. */ 1864 obj_tail = &obj_list; 1865 1866 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1867 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1868 1869#ifndef RTLD_INIT_PAGESIZES_EARLY 1870 /* The page size is required by the dynamic memory allocator. */ 1871 init_pagesizes(aux_info); 1872#endif 1873 1874 if (aux_info[AT_OSRELDATE] != NULL) 1875 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 1876 1877 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 1878 1879 /* Replace the path with a dynamically allocated copy. */ 1880 obj_rtld.path = xstrdup(PATH_RTLD); 1881 1882 r_debug.r_brk = r_debug_state; 1883 r_debug.r_state = RT_CONSISTENT; 1884} 1885 1886/* 1887 * Retrieve the array of supported page sizes. The kernel provides the page 1888 * sizes in increasing order. 1889 */ 1890static void 1891init_pagesizes(Elf_Auxinfo **aux_info) 1892{ 1893 static size_t psa[MAXPAGESIZES]; 1894 int mib[2]; 1895 size_t len, size; 1896 1897 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 1898 NULL) { 1899 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 1900 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 1901 } else { 1902 len = 2; 1903 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 1904 size = sizeof(psa); 1905 else { 1906 /* As a fallback, retrieve the base page size. */ 1907 size = sizeof(psa[0]); 1908 if (aux_info[AT_PAGESZ] != NULL) { 1909 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 1910 goto psa_filled; 1911 } else { 1912 mib[0] = CTL_HW; 1913 mib[1] = HW_PAGESIZE; 1914 len = 2; 1915 } 1916 } 1917 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 1918 _rtld_error("sysctl for hw.pagesize(s) failed"); 1919 rtld_die(); 1920 } 1921psa_filled: 1922 pagesizes = psa; 1923 } 1924 npagesizes = size / sizeof(pagesizes[0]); 1925 /* Discard any invalid entries at the end of the array. */ 1926 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 1927 npagesizes--; 1928} 1929 1930/* 1931 * Add the init functions from a needed object list (and its recursive 1932 * needed objects) to "list". This is not used directly; it is a helper 1933 * function for initlist_add_objects(). The write lock must be held 1934 * when this function is called. 1935 */ 1936static void 1937initlist_add_neededs(Needed_Entry *needed, Objlist *list) 1938{ 1939 /* Recursively process the successor needed objects. */ 1940 if (needed->next != NULL) 1941 initlist_add_neededs(needed->next, list); 1942 1943 /* Process the current needed object. */ 1944 if (needed->obj != NULL) 1945 initlist_add_objects(needed->obj, &needed->obj->next, list); 1946} 1947 1948/* 1949 * Scan all of the DAGs rooted in the range of objects from "obj" to 1950 * "tail" and add their init functions to "list". This recurses over 1951 * the DAGs and ensure the proper init ordering such that each object's 1952 * needed libraries are initialized before the object itself. At the 1953 * same time, this function adds the objects to the global finalization 1954 * list "list_fini" in the opposite order. The write lock must be 1955 * held when this function is called. 1956 */ 1957static void 1958initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list) 1959{ 1960 1961 if (obj->init_scanned || obj->init_done) 1962 return; 1963 obj->init_scanned = true; 1964 1965 /* Recursively process the successor objects. */ 1966 if (&obj->next != tail) 1967 initlist_add_objects(obj->next, tail, list); 1968 1969 /* Recursively process the needed objects. */ 1970 if (obj->needed != NULL) 1971 initlist_add_neededs(obj->needed, list); 1972 if (obj->needed_filtees != NULL) 1973 initlist_add_neededs(obj->needed_filtees, list); 1974 if (obj->needed_aux_filtees != NULL) 1975 initlist_add_neededs(obj->needed_aux_filtees, list); 1976 1977 /* Add the object to the init list. */ 1978 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL || 1979 obj->init_array != (Elf_Addr)NULL) 1980 objlist_push_tail(list, obj); 1981 1982 /* Add the object to the global fini list in the reverse order. */ 1983 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 1984 && !obj->on_fini_list) { 1985 objlist_push_head(&list_fini, obj); 1986 obj->on_fini_list = true; 1987 } 1988} 1989 1990#ifndef FPTR_TARGET 1991#define FPTR_TARGET(f) ((Elf_Addr) (f)) 1992#endif 1993 1994static void 1995free_needed_filtees(Needed_Entry *n) 1996{ 1997 Needed_Entry *needed, *needed1; 1998 1999 for (needed = n; needed != NULL; needed = needed->next) { 2000 if (needed->obj != NULL) { 2001 dlclose(needed->obj); 2002 needed->obj = NULL; 2003 } 2004 } 2005 for (needed = n; needed != NULL; needed = needed1) { 2006 needed1 = needed->next; 2007 free(needed); 2008 } 2009} 2010 2011static void 2012unload_filtees(Obj_Entry *obj) 2013{ 2014 2015 free_needed_filtees(obj->needed_filtees); 2016 obj->needed_filtees = NULL; 2017 free_needed_filtees(obj->needed_aux_filtees); 2018 obj->needed_aux_filtees = NULL; 2019 obj->filtees_loaded = false; 2020} 2021 2022static void 2023load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2024 RtldLockState *lockstate) 2025{ 2026 2027 for (; needed != NULL; needed = needed->next) { 2028 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2029 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2030 RTLD_LOCAL, lockstate); 2031 } 2032} 2033 2034static void 2035load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2036{ 2037 2038 lock_restart_for_upgrade(lockstate); 2039 if (!obj->filtees_loaded) { 2040 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2041 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2042 obj->filtees_loaded = true; 2043 } 2044} 2045 2046static int 2047process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2048{ 2049 Obj_Entry *obj1; 2050 2051 for (; needed != NULL; needed = needed->next) { 2052 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2053 flags & ~RTLD_LO_NOLOAD); 2054 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2055 return (-1); 2056 } 2057 return (0); 2058} 2059 2060/* 2061 * Given a shared object, traverse its list of needed objects, and load 2062 * each of them. Returns 0 on success. Generates an error message and 2063 * returns -1 on failure. 2064 */ 2065static int 2066load_needed_objects(Obj_Entry *first, int flags) 2067{ 2068 Obj_Entry *obj; 2069 2070 for (obj = first; obj != NULL; obj = obj->next) { 2071 if (process_needed(obj, obj->needed, flags) == -1) 2072 return (-1); 2073 } 2074 return (0); 2075} 2076 2077static int 2078load_preload_objects(void) 2079{ 2080 char *p = ld_preload; 2081 Obj_Entry *obj; 2082 static const char delim[] = " \t:;"; 2083 2084 if (p == NULL) 2085 return 0; 2086 2087 p += strspn(p, delim); 2088 while (*p != '\0') { 2089 size_t len = strcspn(p, delim); 2090 char savech; 2091 2092 savech = p[len]; 2093 p[len] = '\0'; 2094 obj = load_object(p, -1, NULL, 0); 2095 if (obj == NULL) 2096 return -1; /* XXX - cleanup */ 2097 obj->z_interpose = true; 2098 p[len] = savech; 2099 p += len; 2100 p += strspn(p, delim); 2101 } 2102 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2103 return 0; 2104} 2105 2106static const char * 2107printable_path(const char *path) 2108{ 2109 2110 return (path == NULL ? "<unknown>" : path); 2111} 2112 2113/* 2114 * Load a shared object into memory, if it is not already loaded. The 2115 * object may be specified by name or by user-supplied file descriptor 2116 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2117 * duplicate is. 2118 * 2119 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2120 * on failure. 2121 */ 2122static Obj_Entry * 2123load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2124{ 2125 Obj_Entry *obj; 2126 int fd; 2127 struct stat sb; 2128 char *path; 2129 2130 if (name != NULL) { 2131 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 2132 if (object_match_name(obj, name)) 2133 return (obj); 2134 } 2135 2136 path = find_library(name, refobj); 2137 if (path == NULL) 2138 return (NULL); 2139 } else 2140 path = NULL; 2141 2142 /* 2143 * If we didn't find a match by pathname, or the name is not 2144 * supplied, open the file and check again by device and inode. 2145 * This avoids false mismatches caused by multiple links or ".." 2146 * in pathnames. 2147 * 2148 * To avoid a race, we open the file and use fstat() rather than 2149 * using stat(). 2150 */ 2151 fd = -1; 2152 if (fd_u == -1) { 2153 if ((fd = open(path, O_RDONLY | O_CLOEXEC)) == -1) { 2154 _rtld_error("Cannot open \"%s\"", path); 2155 free(path); 2156 return (NULL); 2157 } 2158 } else { 2159 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2160 if (fd == -1) { 2161 _rtld_error("Cannot dup fd"); 2162 free(path); 2163 return (NULL); 2164 } 2165 } 2166 if (fstat(fd, &sb) == -1) { 2167 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2168 close(fd); 2169 free(path); 2170 return NULL; 2171 } 2172 for (obj = obj_list->next; obj != NULL; obj = obj->next) 2173 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2174 break; 2175 if (obj != NULL && name != NULL) { 2176 object_add_name(obj, name); 2177 free(path); 2178 close(fd); 2179 return obj; 2180 } 2181 if (flags & RTLD_LO_NOLOAD) { 2182 free(path); 2183 close(fd); 2184 return (NULL); 2185 } 2186 2187 /* First use of this object, so we must map it in */ 2188 obj = do_load_object(fd, name, path, &sb, flags); 2189 if (obj == NULL) 2190 free(path); 2191 close(fd); 2192 2193 return obj; 2194} 2195 2196static Obj_Entry * 2197do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2198 int flags) 2199{ 2200 Obj_Entry *obj; 2201 struct statfs fs; 2202 2203 /* 2204 * but first, make sure that environment variables haven't been 2205 * used to circumvent the noexec flag on a filesystem. 2206 */ 2207 if (dangerous_ld_env) { 2208 if (fstatfs(fd, &fs) != 0) { 2209 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2210 return NULL; 2211 } 2212 if (fs.f_flags & MNT_NOEXEC) { 2213 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 2214 return NULL; 2215 } 2216 } 2217 dbg("loading \"%s\"", printable_path(path)); 2218 obj = map_object(fd, printable_path(path), sbp); 2219 if (obj == NULL) 2220 return NULL; 2221 2222 /* 2223 * If DT_SONAME is present in the object, digest_dynamic2 already 2224 * added it to the object names. 2225 */ 2226 if (name != NULL) 2227 object_add_name(obj, name); 2228 obj->path = path; 2229 digest_dynamic(obj, 0); 2230 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2231 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2232 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2233 RTLD_LO_DLOPEN) { 2234 dbg("refusing to load non-loadable \"%s\"", obj->path); 2235 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2236 munmap(obj->mapbase, obj->mapsize); 2237 obj_free(obj); 2238 return (NULL); 2239 } 2240 2241 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2242 *obj_tail = obj; 2243 obj_tail = &obj->next; 2244 obj_count++; 2245 obj_loads++; 2246 linkmap_add(obj); /* for GDB & dlinfo() */ 2247 max_stack_flags |= obj->stack_flags; 2248 2249 dbg(" %p .. %p: %s", obj->mapbase, 2250 obj->mapbase + obj->mapsize - 1, obj->path); 2251 if (obj->textrel) 2252 dbg(" WARNING: %s has impure text", obj->path); 2253 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2254 obj->path); 2255 2256 return obj; 2257} 2258 2259static Obj_Entry * 2260obj_from_addr(const void *addr) 2261{ 2262 Obj_Entry *obj; 2263 2264 for (obj = obj_list; obj != NULL; obj = obj->next) { 2265 if (addr < (void *) obj->mapbase) 2266 continue; 2267 if (addr < (void *) (obj->mapbase + obj->mapsize)) 2268 return obj; 2269 } 2270 return NULL; 2271} 2272 2273static void 2274preinit_main(void) 2275{ 2276 Elf_Addr *preinit_addr; 2277 int index; 2278 2279 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2280 if (preinit_addr == NULL) 2281 return; 2282 2283 for (index = 0; index < obj_main->preinit_array_num; index++) { 2284 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2285 dbg("calling preinit function for %s at %p", obj_main->path, 2286 (void *)preinit_addr[index]); 2287 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2288 0, 0, obj_main->path); 2289 call_init_pointer(obj_main, preinit_addr[index]); 2290 } 2291 } 2292} 2293 2294/* 2295 * Call the finalization functions for each of the objects in "list" 2296 * belonging to the DAG of "root" and referenced once. If NULL "root" 2297 * is specified, every finalization function will be called regardless 2298 * of the reference count and the list elements won't be freed. All of 2299 * the objects are expected to have non-NULL fini functions. 2300 */ 2301static void 2302objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2303{ 2304 Objlist_Entry *elm; 2305 char *saved_msg; 2306 Elf_Addr *fini_addr; 2307 int index; 2308 2309 assert(root == NULL || root->refcount == 1); 2310 2311 /* 2312 * Preserve the current error message since a fini function might 2313 * call into the dynamic linker and overwrite it. 2314 */ 2315 saved_msg = errmsg_save(); 2316 do { 2317 STAILQ_FOREACH(elm, list, link) { 2318 if (root != NULL && (elm->obj->refcount != 1 || 2319 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2320 continue; 2321 /* Remove object from fini list to prevent recursive invocation. */ 2322 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2323 /* 2324 * XXX: If a dlopen() call references an object while the 2325 * fini function is in progress, we might end up trying to 2326 * unload the referenced object in dlclose() or the object 2327 * won't be unloaded although its fini function has been 2328 * called. 2329 */ 2330 lock_release(rtld_bind_lock, lockstate); 2331 2332 /* 2333 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2334 * When this happens, DT_FINI_ARRAY is processed first. 2335 */ 2336 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2337 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2338 for (index = elm->obj->fini_array_num - 1; index >= 0; 2339 index--) { 2340 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2341 dbg("calling fini function for %s at %p", 2342 elm->obj->path, (void *)fini_addr[index]); 2343 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2344 (void *)fini_addr[index], 0, 0, elm->obj->path); 2345 call_initfini_pointer(elm->obj, fini_addr[index]); 2346 } 2347 } 2348 } 2349 if (elm->obj->fini != (Elf_Addr)NULL) { 2350 dbg("calling fini function for %s at %p", elm->obj->path, 2351 (void *)elm->obj->fini); 2352 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2353 0, 0, elm->obj->path); 2354 call_initfini_pointer(elm->obj, elm->obj->fini); 2355 } 2356 wlock_acquire(rtld_bind_lock, lockstate); 2357 /* No need to free anything if process is going down. */ 2358 if (root != NULL) 2359 free(elm); 2360 /* 2361 * We must restart the list traversal after every fini call 2362 * because a dlclose() call from the fini function or from 2363 * another thread might have modified the reference counts. 2364 */ 2365 break; 2366 } 2367 } while (elm != NULL); 2368 errmsg_restore(saved_msg); 2369} 2370 2371/* 2372 * Call the initialization functions for each of the objects in 2373 * "list". All of the objects are expected to have non-NULL init 2374 * functions. 2375 */ 2376static void 2377objlist_call_init(Objlist *list, RtldLockState *lockstate) 2378{ 2379 Objlist_Entry *elm; 2380 Obj_Entry *obj; 2381 char *saved_msg; 2382 Elf_Addr *init_addr; 2383 int index; 2384 2385 /* 2386 * Clean init_scanned flag so that objects can be rechecked and 2387 * possibly initialized earlier if any of vectors called below 2388 * cause the change by using dlopen. 2389 */ 2390 for (obj = obj_list; obj != NULL; obj = obj->next) 2391 obj->init_scanned = false; 2392 2393 /* 2394 * Preserve the current error message since an init function might 2395 * call into the dynamic linker and overwrite it. 2396 */ 2397 saved_msg = errmsg_save(); 2398 STAILQ_FOREACH(elm, list, link) { 2399 if (elm->obj->init_done) /* Initialized early. */ 2400 continue; 2401 /* 2402 * Race: other thread might try to use this object before current 2403 * one completes the initilization. Not much can be done here 2404 * without better locking. 2405 */ 2406 elm->obj->init_done = true; 2407 lock_release(rtld_bind_lock, lockstate); 2408 2409 /* 2410 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2411 * When this happens, DT_INIT is processed first. 2412 */ 2413 if (elm->obj->init != (Elf_Addr)NULL) { 2414 dbg("calling init function for %s at %p", elm->obj->path, 2415 (void *)elm->obj->init); 2416 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2417 0, 0, elm->obj->path); 2418 call_initfini_pointer(elm->obj, elm->obj->init); 2419 } 2420 init_addr = (Elf_Addr *)elm->obj->init_array; 2421 if (init_addr != NULL) { 2422 for (index = 0; index < elm->obj->init_array_num; index++) { 2423 if (init_addr[index] != 0 && init_addr[index] != 1) { 2424 dbg("calling init function for %s at %p", elm->obj->path, 2425 (void *)init_addr[index]); 2426 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2427 (void *)init_addr[index], 0, 0, elm->obj->path); 2428 call_init_pointer(elm->obj, init_addr[index]); 2429 } 2430 } 2431 } 2432 wlock_acquire(rtld_bind_lock, lockstate); 2433 } 2434 errmsg_restore(saved_msg); 2435} 2436 2437static void 2438objlist_clear(Objlist *list) 2439{ 2440 Objlist_Entry *elm; 2441 2442 while (!STAILQ_EMPTY(list)) { 2443 elm = STAILQ_FIRST(list); 2444 STAILQ_REMOVE_HEAD(list, link); 2445 free(elm); 2446 } 2447} 2448 2449static Objlist_Entry * 2450objlist_find(Objlist *list, const Obj_Entry *obj) 2451{ 2452 Objlist_Entry *elm; 2453 2454 STAILQ_FOREACH(elm, list, link) 2455 if (elm->obj == obj) 2456 return elm; 2457 return NULL; 2458} 2459 2460static void 2461objlist_init(Objlist *list) 2462{ 2463 STAILQ_INIT(list); 2464} 2465 2466static void 2467objlist_push_head(Objlist *list, Obj_Entry *obj) 2468{ 2469 Objlist_Entry *elm; 2470 2471 elm = NEW(Objlist_Entry); 2472 elm->obj = obj; 2473 STAILQ_INSERT_HEAD(list, elm, link); 2474} 2475 2476static void 2477objlist_push_tail(Objlist *list, Obj_Entry *obj) 2478{ 2479 Objlist_Entry *elm; 2480 2481 elm = NEW(Objlist_Entry); 2482 elm->obj = obj; 2483 STAILQ_INSERT_TAIL(list, elm, link); 2484} 2485 2486static void 2487objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2488{ 2489 Objlist_Entry *elm, *listelm; 2490 2491 STAILQ_FOREACH(listelm, list, link) { 2492 if (listelm->obj == listobj) 2493 break; 2494 } 2495 elm = NEW(Objlist_Entry); 2496 elm->obj = obj; 2497 if (listelm != NULL) 2498 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2499 else 2500 STAILQ_INSERT_TAIL(list, elm, link); 2501} 2502 2503static void 2504objlist_remove(Objlist *list, Obj_Entry *obj) 2505{ 2506 Objlist_Entry *elm; 2507 2508 if ((elm = objlist_find(list, obj)) != NULL) { 2509 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2510 free(elm); 2511 } 2512} 2513 2514/* 2515 * Relocate dag rooted in the specified object. 2516 * Returns 0 on success, or -1 on failure. 2517 */ 2518 2519static int 2520relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2521 int flags, RtldLockState *lockstate) 2522{ 2523 Objlist_Entry *elm; 2524 int error; 2525 2526 error = 0; 2527 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2528 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2529 lockstate); 2530 if (error == -1) 2531 break; 2532 } 2533 return (error); 2534} 2535 2536/* 2537 * Relocate single object. 2538 * Returns 0 on success, or -1 on failure. 2539 */ 2540static int 2541relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2542 int flags, RtldLockState *lockstate) 2543{ 2544 2545 if (obj->relocated) 2546 return (0); 2547 obj->relocated = true; 2548 if (obj != rtldobj) 2549 dbg("relocating \"%s\"", obj->path); 2550 2551 if (obj->symtab == NULL || obj->strtab == NULL || 2552 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2553 _rtld_error("%s: Shared object has no run-time symbol table", 2554 obj->path); 2555 return (-1); 2556 } 2557 2558 if (obj->textrel) { 2559 /* There are relocations to the write-protected text segment. */ 2560 if (mprotect(obj->mapbase, obj->textsize, 2561 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) { 2562 _rtld_error("%s: Cannot write-enable text segment: %s", 2563 obj->path, rtld_strerror(errno)); 2564 return (-1); 2565 } 2566 } 2567 2568 /* Process the non-PLT non-IFUNC relocations. */ 2569 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2570 return (-1); 2571 2572 if (obj->textrel) { /* Re-protected the text segment. */ 2573 if (mprotect(obj->mapbase, obj->textsize, 2574 PROT_READ|PROT_EXEC) == -1) { 2575 _rtld_error("%s: Cannot write-protect text segment: %s", 2576 obj->path, rtld_strerror(errno)); 2577 return (-1); 2578 } 2579 } 2580 2581 /* Set the special PLT or GOT entries. */ 2582 init_pltgot(obj); 2583 2584 /* Process the PLT relocations. */ 2585 if (reloc_plt(obj) == -1) 2586 return (-1); 2587 /* Relocate the jump slots if we are doing immediate binding. */ 2588 if (obj->bind_now || bind_now) 2589 if (reloc_jmpslots(obj, flags, lockstate) == -1) 2590 return (-1); 2591 2592 /* 2593 * Process the non-PLT IFUNC relocations. The relocations are 2594 * processed in two phases, because IFUNC resolvers may 2595 * reference other symbols, which must be readily processed 2596 * before resolvers are called. 2597 */ 2598 if (obj->non_plt_gnu_ifunc && 2599 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate)) 2600 return (-1); 2601 2602 if (obj->relro_size > 0) { 2603 if (mprotect(obj->relro_page, obj->relro_size, 2604 PROT_READ) == -1) { 2605 _rtld_error("%s: Cannot enforce relro protection: %s", 2606 obj->path, rtld_strerror(errno)); 2607 return (-1); 2608 } 2609 } 2610 2611 /* 2612 * Set up the magic number and version in the Obj_Entry. These 2613 * were checked in the crt1.o from the original ElfKit, so we 2614 * set them for backward compatibility. 2615 */ 2616 obj->magic = RTLD_MAGIC; 2617 obj->version = RTLD_VERSION; 2618 2619 return (0); 2620} 2621 2622/* 2623 * Relocate newly-loaded shared objects. The argument is a pointer to 2624 * the Obj_Entry for the first such object. All objects from the first 2625 * to the end of the list of objects are relocated. Returns 0 on success, 2626 * or -1 on failure. 2627 */ 2628static int 2629relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2630 int flags, RtldLockState *lockstate) 2631{ 2632 Obj_Entry *obj; 2633 int error; 2634 2635 for (error = 0, obj = first; obj != NULL; obj = obj->next) { 2636 error = relocate_object(obj, bind_now, rtldobj, flags, 2637 lockstate); 2638 if (error == -1) 2639 break; 2640 } 2641 return (error); 2642} 2643 2644/* 2645 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2646 * referencing STT_GNU_IFUNC symbols is postponed till the other 2647 * relocations are done. The indirect functions specified as 2648 * ifunc are allowed to call other symbols, so we need to have 2649 * objects relocated before asking for resolution from indirects. 2650 * 2651 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2652 * instead of the usual lazy handling of PLT slots. It is 2653 * consistent with how GNU does it. 2654 */ 2655static int 2656resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2657 RtldLockState *lockstate) 2658{ 2659 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2660 return (-1); 2661 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2662 reloc_gnu_ifunc(obj, flags, lockstate) == -1) 2663 return (-1); 2664 return (0); 2665} 2666 2667static int 2668resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags, 2669 RtldLockState *lockstate) 2670{ 2671 Obj_Entry *obj; 2672 2673 for (obj = first; obj != NULL; obj = obj->next) { 2674 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1) 2675 return (-1); 2676 } 2677 return (0); 2678} 2679 2680static int 2681initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2682 RtldLockState *lockstate) 2683{ 2684 Objlist_Entry *elm; 2685 2686 STAILQ_FOREACH(elm, list, link) { 2687 if (resolve_object_ifunc(elm->obj, bind_now, flags, 2688 lockstate) == -1) 2689 return (-1); 2690 } 2691 return (0); 2692} 2693 2694/* 2695 * Cleanup procedure. It will be called (by the atexit mechanism) just 2696 * before the process exits. 2697 */ 2698static void 2699rtld_exit(void) 2700{ 2701 RtldLockState lockstate; 2702 2703 wlock_acquire(rtld_bind_lock, &lockstate); 2704 dbg("rtld_exit()"); 2705 objlist_call_fini(&list_fini, NULL, &lockstate); 2706 /* No need to remove the items from the list, since we are exiting. */ 2707 if (!libmap_disable) 2708 lm_fini(); 2709 lock_release(rtld_bind_lock, &lockstate); 2710} 2711 2712/* 2713 * Iterate over a search path, translate each element, and invoke the 2714 * callback on the result. 2715 */ 2716static void * 2717path_enumerate(const char *path, path_enum_proc callback, void *arg) 2718{ 2719 const char *trans; 2720 if (path == NULL) 2721 return (NULL); 2722 2723 path += strspn(path, ":;"); 2724 while (*path != '\0') { 2725 size_t len; 2726 char *res; 2727 2728 len = strcspn(path, ":;"); 2729 trans = lm_findn(NULL, path, len); 2730 if (trans) 2731 res = callback(trans, strlen(trans), arg); 2732 else 2733 res = callback(path, len, arg); 2734 2735 if (res != NULL) 2736 return (res); 2737 2738 path += len; 2739 path += strspn(path, ":;"); 2740 } 2741 2742 return (NULL); 2743} 2744 2745struct try_library_args { 2746 const char *name; 2747 size_t namelen; 2748 char *buffer; 2749 size_t buflen; 2750}; 2751 2752static void * 2753try_library_path(const char *dir, size_t dirlen, void *param) 2754{ 2755 struct try_library_args *arg; 2756 2757 arg = param; 2758 if (*dir == '/' || trust) { 2759 char *pathname; 2760 2761 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 2762 return (NULL); 2763 2764 pathname = arg->buffer; 2765 strncpy(pathname, dir, dirlen); 2766 pathname[dirlen] = '/'; 2767 strcpy(pathname + dirlen + 1, arg->name); 2768 2769 dbg(" Trying \"%s\"", pathname); 2770 if (access(pathname, F_OK) == 0) { /* We found it */ 2771 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 2772 strcpy(pathname, arg->buffer); 2773 return (pathname); 2774 } 2775 } 2776 return (NULL); 2777} 2778 2779static char * 2780search_library_path(const char *name, const char *path) 2781{ 2782 char *p; 2783 struct try_library_args arg; 2784 2785 if (path == NULL) 2786 return NULL; 2787 2788 arg.name = name; 2789 arg.namelen = strlen(name); 2790 arg.buffer = xmalloc(PATH_MAX); 2791 arg.buflen = PATH_MAX; 2792 2793 p = path_enumerate(path, try_library_path, &arg); 2794 2795 free(arg.buffer); 2796 2797 return (p); 2798} 2799 2800int 2801dlclose(void *handle) 2802{ 2803 Obj_Entry *root; 2804 RtldLockState lockstate; 2805 2806 wlock_acquire(rtld_bind_lock, &lockstate); 2807 root = dlcheck(handle); 2808 if (root == NULL) { 2809 lock_release(rtld_bind_lock, &lockstate); 2810 return -1; 2811 } 2812 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 2813 root->path); 2814 2815 /* Unreference the object and its dependencies. */ 2816 root->dl_refcount--; 2817 2818 if (root->refcount == 1) { 2819 /* 2820 * The object will be no longer referenced, so we must unload it. 2821 * First, call the fini functions. 2822 */ 2823 objlist_call_fini(&list_fini, root, &lockstate); 2824 2825 unref_dag(root); 2826 2827 /* Finish cleaning up the newly-unreferenced objects. */ 2828 GDB_STATE(RT_DELETE,&root->linkmap); 2829 unload_object(root); 2830 GDB_STATE(RT_CONSISTENT,NULL); 2831 } else 2832 unref_dag(root); 2833 2834 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 2835 lock_release(rtld_bind_lock, &lockstate); 2836 return 0; 2837} 2838 2839char * 2840dlerror(void) 2841{ 2842 char *msg = error_message; 2843 error_message = NULL; 2844 return msg; 2845} 2846 2847/* 2848 * This function is deprecated and has no effect. 2849 */ 2850void 2851dllockinit(void *context, 2852 void *(*lock_create)(void *context), 2853 void (*rlock_acquire)(void *lock), 2854 void (*wlock_acquire)(void *lock), 2855 void (*lock_release)(void *lock), 2856 void (*lock_destroy)(void *lock), 2857 void (*context_destroy)(void *context)) 2858{ 2859 static void *cur_context; 2860 static void (*cur_context_destroy)(void *); 2861 2862 /* Just destroy the context from the previous call, if necessary. */ 2863 if (cur_context_destroy != NULL) 2864 cur_context_destroy(cur_context); 2865 cur_context = context; 2866 cur_context_destroy = context_destroy; 2867} 2868 2869void * 2870dlopen(const char *name, int mode) 2871{ 2872 2873 return (rtld_dlopen(name, -1, mode)); 2874} 2875 2876void * 2877fdlopen(int fd, int mode) 2878{ 2879 2880 return (rtld_dlopen(NULL, fd, mode)); 2881} 2882 2883static void * 2884rtld_dlopen(const char *name, int fd, int mode) 2885{ 2886 RtldLockState lockstate; 2887 int lo_flags; 2888 2889 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 2890 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 2891 if (ld_tracing != NULL) { 2892 rlock_acquire(rtld_bind_lock, &lockstate); 2893 if (sigsetjmp(lockstate.env, 0) != 0) 2894 lock_upgrade(rtld_bind_lock, &lockstate); 2895 environ = (char **)*get_program_var_addr("environ", &lockstate); 2896 lock_release(rtld_bind_lock, &lockstate); 2897 } 2898 lo_flags = RTLD_LO_DLOPEN; 2899 if (mode & RTLD_NODELETE) 2900 lo_flags |= RTLD_LO_NODELETE; 2901 if (mode & RTLD_NOLOAD) 2902 lo_flags |= RTLD_LO_NOLOAD; 2903 if (ld_tracing != NULL) 2904 lo_flags |= RTLD_LO_TRACE; 2905 2906 return (dlopen_object(name, fd, obj_main, lo_flags, 2907 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 2908} 2909 2910static void 2911dlopen_cleanup(Obj_Entry *obj) 2912{ 2913 2914 obj->dl_refcount--; 2915 unref_dag(obj); 2916 if (obj->refcount == 0) 2917 unload_object(obj); 2918} 2919 2920static Obj_Entry * 2921dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 2922 int mode, RtldLockState *lockstate) 2923{ 2924 Obj_Entry **old_obj_tail; 2925 Obj_Entry *obj; 2926 Objlist initlist; 2927 RtldLockState mlockstate; 2928 int result; 2929 2930 objlist_init(&initlist); 2931 2932 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 2933 wlock_acquire(rtld_bind_lock, &mlockstate); 2934 lockstate = &mlockstate; 2935 } 2936 GDB_STATE(RT_ADD,NULL); 2937 2938 old_obj_tail = obj_tail; 2939 obj = NULL; 2940 if (name == NULL && fd == -1) { 2941 obj = obj_main; 2942 obj->refcount++; 2943 } else { 2944 obj = load_object(name, fd, refobj, lo_flags); 2945 } 2946 2947 if (obj) { 2948 obj->dl_refcount++; 2949 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 2950 objlist_push_tail(&list_global, obj); 2951 if (*old_obj_tail != NULL) { /* We loaded something new. */ 2952 assert(*old_obj_tail == obj); 2953 result = load_needed_objects(obj, 2954 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 2955 init_dag(obj); 2956 ref_dag(obj); 2957 if (result != -1) 2958 result = rtld_verify_versions(&obj->dagmembers); 2959 if (result != -1 && ld_tracing) 2960 goto trace; 2961 if (result == -1 || relocate_object_dag(obj, 2962 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 2963 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 2964 lockstate) == -1) { 2965 dlopen_cleanup(obj); 2966 obj = NULL; 2967 } else if (lo_flags & RTLD_LO_EARLY) { 2968 /* 2969 * Do not call the init functions for early loaded 2970 * filtees. The image is still not initialized enough 2971 * for them to work. 2972 * 2973 * Our object is found by the global object list and 2974 * will be ordered among all init calls done right 2975 * before transferring control to main. 2976 */ 2977 } else { 2978 /* Make list of init functions to call. */ 2979 initlist_add_objects(obj, &obj->next, &initlist); 2980 } 2981 /* 2982 * Process all no_delete or global objects here, given 2983 * them own DAGs to prevent their dependencies from being 2984 * unloaded. This has to be done after we have loaded all 2985 * of the dependencies, so that we do not miss any. 2986 */ 2987 if (obj != NULL) 2988 process_z(obj); 2989 } else { 2990 /* 2991 * Bump the reference counts for objects on this DAG. If 2992 * this is the first dlopen() call for the object that was 2993 * already loaded as a dependency, initialize the dag 2994 * starting at it. 2995 */ 2996 init_dag(obj); 2997 ref_dag(obj); 2998 2999 if ((lo_flags & RTLD_LO_TRACE) != 0) 3000 goto trace; 3001 } 3002 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3003 obj->z_nodelete) && !obj->ref_nodel) { 3004 dbg("obj %s nodelete", obj->path); 3005 ref_dag(obj); 3006 obj->z_nodelete = obj->ref_nodel = true; 3007 } 3008 } 3009 3010 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3011 name); 3012 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3013 3014 if (!(lo_flags & RTLD_LO_EARLY)) { 3015 map_stacks_exec(lockstate); 3016 } 3017 3018 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3019 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3020 lockstate) == -1) { 3021 objlist_clear(&initlist); 3022 dlopen_cleanup(obj); 3023 if (lockstate == &mlockstate) 3024 lock_release(rtld_bind_lock, lockstate); 3025 return (NULL); 3026 } 3027 3028 if (!(lo_flags & RTLD_LO_EARLY)) { 3029 /* Call the init functions. */ 3030 objlist_call_init(&initlist, lockstate); 3031 } 3032 objlist_clear(&initlist); 3033 if (lockstate == &mlockstate) 3034 lock_release(rtld_bind_lock, lockstate); 3035 return obj; 3036trace: 3037 trace_loaded_objects(obj); 3038 if (lockstate == &mlockstate) 3039 lock_release(rtld_bind_lock, lockstate); 3040 exit(0); 3041} 3042 3043static void * 3044do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3045 int flags) 3046{ 3047 DoneList donelist; 3048 const Obj_Entry *obj, *defobj; 3049 const Elf_Sym *def; 3050 SymLook req; 3051 RtldLockState lockstate; 3052#ifndef __ia64__ 3053 tls_index ti; 3054#endif 3055 void *sym; 3056 int res; 3057 3058 def = NULL; 3059 defobj = NULL; 3060 symlook_init(&req, name); 3061 req.ventry = ve; 3062 req.flags = flags | SYMLOOK_IN_PLT; 3063 req.lockstate = &lockstate; 3064 3065 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3066 rlock_acquire(rtld_bind_lock, &lockstate); 3067 if (sigsetjmp(lockstate.env, 0) != 0) 3068 lock_upgrade(rtld_bind_lock, &lockstate); 3069 if (handle == NULL || handle == RTLD_NEXT || 3070 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3071 3072 if ((obj = obj_from_addr(retaddr)) == NULL) { 3073 _rtld_error("Cannot determine caller's shared object"); 3074 lock_release(rtld_bind_lock, &lockstate); 3075 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3076 return NULL; 3077 } 3078 if (handle == NULL) { /* Just the caller's shared object. */ 3079 res = symlook_obj(&req, obj); 3080 if (res == 0) { 3081 def = req.sym_out; 3082 defobj = req.defobj_out; 3083 } 3084 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3085 handle == RTLD_SELF) { /* ... caller included */ 3086 if (handle == RTLD_NEXT) 3087 obj = obj->next; 3088 for (; obj != NULL; obj = obj->next) { 3089 res = symlook_obj(&req, obj); 3090 if (res == 0) { 3091 if (def == NULL || 3092 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3093 def = req.sym_out; 3094 defobj = req.defobj_out; 3095 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3096 break; 3097 } 3098 } 3099 } 3100 /* 3101 * Search the dynamic linker itself, and possibly resolve the 3102 * symbol from there. This is how the application links to 3103 * dynamic linker services such as dlopen. 3104 */ 3105 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3106 res = symlook_obj(&req, &obj_rtld); 3107 if (res == 0) { 3108 def = req.sym_out; 3109 defobj = req.defobj_out; 3110 } 3111 } 3112 } else { 3113 assert(handle == RTLD_DEFAULT); 3114 res = symlook_default(&req, obj); 3115 if (res == 0) { 3116 defobj = req.defobj_out; 3117 def = req.sym_out; 3118 } 3119 } 3120 } else { 3121 if ((obj = dlcheck(handle)) == NULL) { 3122 lock_release(rtld_bind_lock, &lockstate); 3123 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3124 return NULL; 3125 } 3126 3127 donelist_init(&donelist); 3128 if (obj->mainprog) { 3129 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3130 res = symlook_global(&req, &donelist); 3131 if (res == 0) { 3132 def = req.sym_out; 3133 defobj = req.defobj_out; 3134 } 3135 /* 3136 * Search the dynamic linker itself, and possibly resolve the 3137 * symbol from there. This is how the application links to 3138 * dynamic linker services such as dlopen. 3139 */ 3140 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3141 res = symlook_obj(&req, &obj_rtld); 3142 if (res == 0) { 3143 def = req.sym_out; 3144 defobj = req.defobj_out; 3145 } 3146 } 3147 } 3148 else { 3149 /* Search the whole DAG rooted at the given object. */ 3150 res = symlook_list(&req, &obj->dagmembers, &donelist); 3151 if (res == 0) { 3152 def = req.sym_out; 3153 defobj = req.defobj_out; 3154 } 3155 } 3156 } 3157 3158 if (def != NULL) { 3159 lock_release(rtld_bind_lock, &lockstate); 3160 3161 /* 3162 * The value required by the caller is derived from the value 3163 * of the symbol. For the ia64 architecture, we need to 3164 * construct a function descriptor which the caller can use to 3165 * call the function with the right 'gp' value. For other 3166 * architectures and for non-functions, the value is simply 3167 * the relocated value of the symbol. 3168 */ 3169 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3170 sym = make_function_pointer(def, defobj); 3171 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3172 sym = rtld_resolve_ifunc(defobj, def); 3173 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3174#ifdef __ia64__ 3175 return (__tls_get_addr(defobj->tlsindex, def->st_value)); 3176#else 3177 ti.ti_module = defobj->tlsindex; 3178 ti.ti_offset = def->st_value; 3179 sym = __tls_get_addr(&ti); 3180#endif 3181 } else 3182 sym = defobj->relocbase + def->st_value; 3183 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3184 return (sym); 3185 } 3186 3187 _rtld_error("Undefined symbol \"%s\"", name); 3188 lock_release(rtld_bind_lock, &lockstate); 3189 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3190 return NULL; 3191} 3192 3193void * 3194dlsym(void *handle, const char *name) 3195{ 3196 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3197 SYMLOOK_DLSYM); 3198} 3199 3200dlfunc_t 3201dlfunc(void *handle, const char *name) 3202{ 3203 union { 3204 void *d; 3205 dlfunc_t f; 3206 } rv; 3207 3208 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3209 SYMLOOK_DLSYM); 3210 return (rv.f); 3211} 3212 3213void * 3214dlvsym(void *handle, const char *name, const char *version) 3215{ 3216 Ver_Entry ventry; 3217 3218 ventry.name = version; 3219 ventry.file = NULL; 3220 ventry.hash = elf_hash(version); 3221 ventry.flags= 0; 3222 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3223 SYMLOOK_DLSYM); 3224} 3225 3226int 3227_rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3228{ 3229 const Obj_Entry *obj; 3230 RtldLockState lockstate; 3231 3232 rlock_acquire(rtld_bind_lock, &lockstate); 3233 obj = obj_from_addr(addr); 3234 if (obj == NULL) { 3235 _rtld_error("No shared object contains address"); 3236 lock_release(rtld_bind_lock, &lockstate); 3237 return (0); 3238 } 3239 rtld_fill_dl_phdr_info(obj, phdr_info); 3240 lock_release(rtld_bind_lock, &lockstate); 3241 return (1); 3242} 3243 3244int 3245dladdr(const void *addr, Dl_info *info) 3246{ 3247 const Obj_Entry *obj; 3248 const Elf_Sym *def; 3249 void *symbol_addr; 3250 unsigned long symoffset; 3251 RtldLockState lockstate; 3252 3253 rlock_acquire(rtld_bind_lock, &lockstate); 3254 obj = obj_from_addr(addr); 3255 if (obj == NULL) { 3256 _rtld_error("No shared object contains address"); 3257 lock_release(rtld_bind_lock, &lockstate); 3258 return 0; 3259 } 3260 info->dli_fname = obj->path; 3261 info->dli_fbase = obj->mapbase; 3262 info->dli_saddr = (void *)0; 3263 info->dli_sname = NULL; 3264 3265 /* 3266 * Walk the symbol list looking for the symbol whose address is 3267 * closest to the address sent in. 3268 */ 3269 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3270 def = obj->symtab + symoffset; 3271 3272 /* 3273 * For skip the symbol if st_shndx is either SHN_UNDEF or 3274 * SHN_COMMON. 3275 */ 3276 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3277 continue; 3278 3279 /* 3280 * If the symbol is greater than the specified address, or if it 3281 * is further away from addr than the current nearest symbol, 3282 * then reject it. 3283 */ 3284 symbol_addr = obj->relocbase + def->st_value; 3285 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3286 continue; 3287 3288 /* Update our idea of the nearest symbol. */ 3289 info->dli_sname = obj->strtab + def->st_name; 3290 info->dli_saddr = symbol_addr; 3291 3292 /* Exact match? */ 3293 if (info->dli_saddr == addr) 3294 break; 3295 } 3296 lock_release(rtld_bind_lock, &lockstate); 3297 return 1; 3298} 3299 3300int 3301dlinfo(void *handle, int request, void *p) 3302{ 3303 const Obj_Entry *obj; 3304 RtldLockState lockstate; 3305 int error; 3306 3307 rlock_acquire(rtld_bind_lock, &lockstate); 3308 3309 if (handle == NULL || handle == RTLD_SELF) { 3310 void *retaddr; 3311 3312 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3313 if ((obj = obj_from_addr(retaddr)) == NULL) 3314 _rtld_error("Cannot determine caller's shared object"); 3315 } else 3316 obj = dlcheck(handle); 3317 3318 if (obj == NULL) { 3319 lock_release(rtld_bind_lock, &lockstate); 3320 return (-1); 3321 } 3322 3323 error = 0; 3324 switch (request) { 3325 case RTLD_DI_LINKMAP: 3326 *((struct link_map const **)p) = &obj->linkmap; 3327 break; 3328 case RTLD_DI_ORIGIN: 3329 error = rtld_dirname(obj->path, p); 3330 break; 3331 3332 case RTLD_DI_SERINFOSIZE: 3333 case RTLD_DI_SERINFO: 3334 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3335 break; 3336 3337 default: 3338 _rtld_error("Invalid request %d passed to dlinfo()", request); 3339 error = -1; 3340 } 3341 3342 lock_release(rtld_bind_lock, &lockstate); 3343 3344 return (error); 3345} 3346 3347static void 3348rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3349{ 3350 3351 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3352 phdr_info->dlpi_name = obj->path; 3353 phdr_info->dlpi_phdr = obj->phdr; 3354 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3355 phdr_info->dlpi_tls_modid = obj->tlsindex; 3356 phdr_info->dlpi_tls_data = obj->tlsinit; 3357 phdr_info->dlpi_adds = obj_loads; 3358 phdr_info->dlpi_subs = obj_loads - obj_count; 3359} 3360 3361int 3362dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3363{ 3364 struct dl_phdr_info phdr_info; 3365 const Obj_Entry *obj; 3366 RtldLockState bind_lockstate, phdr_lockstate; 3367 int error; 3368 3369 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3370 rlock_acquire(rtld_bind_lock, &bind_lockstate); 3371 3372 error = 0; 3373 3374 for (obj = obj_list; obj != NULL; obj = obj->next) { 3375 rtld_fill_dl_phdr_info(obj, &phdr_info); 3376 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0) 3377 break; 3378 3379 } 3380 lock_release(rtld_bind_lock, &bind_lockstate); 3381 lock_release(rtld_phdr_lock, &phdr_lockstate); 3382 3383 return (error); 3384} 3385 3386static void * 3387fill_search_info(const char *dir, size_t dirlen, void *param) 3388{ 3389 struct fill_search_info_args *arg; 3390 3391 arg = param; 3392 3393 if (arg->request == RTLD_DI_SERINFOSIZE) { 3394 arg->serinfo->dls_cnt ++; 3395 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3396 } else { 3397 struct dl_serpath *s_entry; 3398 3399 s_entry = arg->serpath; 3400 s_entry->dls_name = arg->strspace; 3401 s_entry->dls_flags = arg->flags; 3402 3403 strncpy(arg->strspace, dir, dirlen); 3404 arg->strspace[dirlen] = '\0'; 3405 3406 arg->strspace += dirlen + 1; 3407 arg->serpath++; 3408 } 3409 3410 return (NULL); 3411} 3412 3413static int 3414do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3415{ 3416 struct dl_serinfo _info; 3417 struct fill_search_info_args args; 3418 3419 args.request = RTLD_DI_SERINFOSIZE; 3420 args.serinfo = &_info; 3421 3422 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3423 _info.dls_cnt = 0; 3424 3425 path_enumerate(obj->rpath, fill_search_info, &args); 3426 path_enumerate(ld_library_path, fill_search_info, &args); 3427 path_enumerate(obj->runpath, fill_search_info, &args); 3428 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args); 3429 if (!obj->z_nodeflib) 3430 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 3431 3432 3433 if (request == RTLD_DI_SERINFOSIZE) { 3434 info->dls_size = _info.dls_size; 3435 info->dls_cnt = _info.dls_cnt; 3436 return (0); 3437 } 3438 3439 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3440 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3441 return (-1); 3442 } 3443 3444 args.request = RTLD_DI_SERINFO; 3445 args.serinfo = info; 3446 args.serpath = &info->dls_serpath[0]; 3447 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3448 3449 args.flags = LA_SER_RUNPATH; 3450 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 3451 return (-1); 3452 3453 args.flags = LA_SER_LIBPATH; 3454 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 3455 return (-1); 3456 3457 args.flags = LA_SER_RUNPATH; 3458 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL) 3459 return (-1); 3460 3461 args.flags = LA_SER_CONFIG; 3462 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args) 3463 != NULL) 3464 return (-1); 3465 3466 args.flags = LA_SER_DEFAULT; 3467 if (!obj->z_nodeflib && 3468 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 3469 return (-1); 3470 return (0); 3471} 3472 3473static int 3474rtld_dirname(const char *path, char *bname) 3475{ 3476 const char *endp; 3477 3478 /* Empty or NULL string gets treated as "." */ 3479 if (path == NULL || *path == '\0') { 3480 bname[0] = '.'; 3481 bname[1] = '\0'; 3482 return (0); 3483 } 3484 3485 /* Strip trailing slashes */ 3486 endp = path + strlen(path) - 1; 3487 while (endp > path && *endp == '/') 3488 endp--; 3489 3490 /* Find the start of the dir */ 3491 while (endp > path && *endp != '/') 3492 endp--; 3493 3494 /* Either the dir is "/" or there are no slashes */ 3495 if (endp == path) { 3496 bname[0] = *endp == '/' ? '/' : '.'; 3497 bname[1] = '\0'; 3498 return (0); 3499 } else { 3500 do { 3501 endp--; 3502 } while (endp > path && *endp == '/'); 3503 } 3504 3505 if (endp - path + 2 > PATH_MAX) 3506 { 3507 _rtld_error("Filename is too long: %s", path); 3508 return(-1); 3509 } 3510 3511 strncpy(bname, path, endp - path + 1); 3512 bname[endp - path + 1] = '\0'; 3513 return (0); 3514} 3515 3516static int 3517rtld_dirname_abs(const char *path, char *base) 3518{ 3519 char *last; 3520 3521 if (realpath(path, base) == NULL) 3522 return (-1); 3523 dbg("%s -> %s", path, base); 3524 last = strrchr(base, '/'); 3525 if (last == NULL) 3526 return (-1); 3527 if (last != base) 3528 *last = '\0'; 3529 return (0); 3530} 3531 3532static void 3533linkmap_add(Obj_Entry *obj) 3534{ 3535 struct link_map *l = &obj->linkmap; 3536 struct link_map *prev; 3537 3538 obj->linkmap.l_name = obj->path; 3539 obj->linkmap.l_addr = obj->mapbase; 3540 obj->linkmap.l_ld = obj->dynamic; 3541#ifdef __mips__ 3542 /* GDB needs load offset on MIPS to use the symbols */ 3543 obj->linkmap.l_offs = obj->relocbase; 3544#endif 3545 3546 if (r_debug.r_map == NULL) { 3547 r_debug.r_map = l; 3548 return; 3549 } 3550 3551 /* 3552 * Scan to the end of the list, but not past the entry for the 3553 * dynamic linker, which we want to keep at the very end. 3554 */ 3555 for (prev = r_debug.r_map; 3556 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3557 prev = prev->l_next) 3558 ; 3559 3560 /* Link in the new entry. */ 3561 l->l_prev = prev; 3562 l->l_next = prev->l_next; 3563 if (l->l_next != NULL) 3564 l->l_next->l_prev = l; 3565 prev->l_next = l; 3566} 3567 3568static void 3569linkmap_delete(Obj_Entry *obj) 3570{ 3571 struct link_map *l = &obj->linkmap; 3572 3573 if (l->l_prev == NULL) { 3574 if ((r_debug.r_map = l->l_next) != NULL) 3575 l->l_next->l_prev = NULL; 3576 return; 3577 } 3578 3579 if ((l->l_prev->l_next = l->l_next) != NULL) 3580 l->l_next->l_prev = l->l_prev; 3581} 3582 3583/* 3584 * Function for the debugger to set a breakpoint on to gain control. 3585 * 3586 * The two parameters allow the debugger to easily find and determine 3587 * what the runtime loader is doing and to whom it is doing it. 3588 * 3589 * When the loadhook trap is hit (r_debug_state, set at program 3590 * initialization), the arguments can be found on the stack: 3591 * 3592 * +8 struct link_map *m 3593 * +4 struct r_debug *rd 3594 * +0 RetAddr 3595 */ 3596void 3597r_debug_state(struct r_debug* rd, struct link_map *m) 3598{ 3599 /* 3600 * The following is a hack to force the compiler to emit calls to 3601 * this function, even when optimizing. If the function is empty, 3602 * the compiler is not obliged to emit any code for calls to it, 3603 * even when marked __noinline. However, gdb depends on those 3604 * calls being made. 3605 */ 3606 __compiler_membar(); 3607} 3608 3609/* 3610 * A function called after init routines have completed. This can be used to 3611 * break before a program's entry routine is called, and can be used when 3612 * main is not available in the symbol table. 3613 */ 3614void 3615_r_debug_postinit(struct link_map *m) 3616{ 3617 3618 /* See r_debug_state(). */ 3619 __compiler_membar(); 3620} 3621 3622/* 3623 * Get address of the pointer variable in the main program. 3624 * Prefer non-weak symbol over the weak one. 3625 */ 3626static const void ** 3627get_program_var_addr(const char *name, RtldLockState *lockstate) 3628{ 3629 SymLook req; 3630 DoneList donelist; 3631 3632 symlook_init(&req, name); 3633 req.lockstate = lockstate; 3634 donelist_init(&donelist); 3635 if (symlook_global(&req, &donelist) != 0) 3636 return (NULL); 3637 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 3638 return ((const void **)make_function_pointer(req.sym_out, 3639 req.defobj_out)); 3640 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 3641 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 3642 else 3643 return ((const void **)(req.defobj_out->relocbase + 3644 req.sym_out->st_value)); 3645} 3646 3647/* 3648 * Set a pointer variable in the main program to the given value. This 3649 * is used to set key variables such as "environ" before any of the 3650 * init functions are called. 3651 */ 3652static void 3653set_program_var(const char *name, const void *value) 3654{ 3655 const void **addr; 3656 3657 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 3658 dbg("\"%s\": *%p <-- %p", name, addr, value); 3659 *addr = value; 3660 } 3661} 3662 3663/* 3664 * Search the global objects, including dependencies and main object, 3665 * for the given symbol. 3666 */ 3667static int 3668symlook_global(SymLook *req, DoneList *donelist) 3669{ 3670 SymLook req1; 3671 const Objlist_Entry *elm; 3672 int res; 3673 3674 symlook_init_from_req(&req1, req); 3675 3676 /* Search all objects loaded at program start up. */ 3677 if (req->defobj_out == NULL || 3678 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3679 res = symlook_list(&req1, &list_main, donelist); 3680 if (res == 0 && (req->defobj_out == NULL || 3681 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3682 req->sym_out = req1.sym_out; 3683 req->defobj_out = req1.defobj_out; 3684 assert(req->defobj_out != NULL); 3685 } 3686 } 3687 3688 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 3689 STAILQ_FOREACH(elm, &list_global, link) { 3690 if (req->defobj_out != NULL && 3691 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3692 break; 3693 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 3694 if (res == 0 && (req->defobj_out == NULL || 3695 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3696 req->sym_out = req1.sym_out; 3697 req->defobj_out = req1.defobj_out; 3698 assert(req->defobj_out != NULL); 3699 } 3700 } 3701 3702 return (req->sym_out != NULL ? 0 : ESRCH); 3703} 3704 3705/* 3706 * Given a symbol name in a referencing object, find the corresponding 3707 * definition of the symbol. Returns a pointer to the symbol, or NULL if 3708 * no definition was found. Returns a pointer to the Obj_Entry of the 3709 * defining object via the reference parameter DEFOBJ_OUT. 3710 */ 3711static int 3712symlook_default(SymLook *req, const Obj_Entry *refobj) 3713{ 3714 DoneList donelist; 3715 const Objlist_Entry *elm; 3716 SymLook req1; 3717 int res; 3718 3719 donelist_init(&donelist); 3720 symlook_init_from_req(&req1, req); 3721 3722 /* Look first in the referencing object if linked symbolically. */ 3723 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 3724 res = symlook_obj(&req1, refobj); 3725 if (res == 0) { 3726 req->sym_out = req1.sym_out; 3727 req->defobj_out = req1.defobj_out; 3728 assert(req->defobj_out != NULL); 3729 } 3730 } 3731 3732 symlook_global(req, &donelist); 3733 3734 /* Search all dlopened DAGs containing the referencing object. */ 3735 STAILQ_FOREACH(elm, &refobj->dldags, link) { 3736 if (req->sym_out != NULL && 3737 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3738 break; 3739 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 3740 if (res == 0 && (req->sym_out == NULL || 3741 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3742 req->sym_out = req1.sym_out; 3743 req->defobj_out = req1.defobj_out; 3744 assert(req->defobj_out != NULL); 3745 } 3746 } 3747 3748 /* 3749 * Search the dynamic linker itself, and possibly resolve the 3750 * symbol from there. This is how the application links to 3751 * dynamic linker services such as dlopen. 3752 */ 3753 if (req->sym_out == NULL || 3754 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3755 res = symlook_obj(&req1, &obj_rtld); 3756 if (res == 0) { 3757 req->sym_out = req1.sym_out; 3758 req->defobj_out = req1.defobj_out; 3759 assert(req->defobj_out != NULL); 3760 } 3761 } 3762 3763 return (req->sym_out != NULL ? 0 : ESRCH); 3764} 3765 3766static int 3767symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 3768{ 3769 const Elf_Sym *def; 3770 const Obj_Entry *defobj; 3771 const Objlist_Entry *elm; 3772 SymLook req1; 3773 int res; 3774 3775 def = NULL; 3776 defobj = NULL; 3777 STAILQ_FOREACH(elm, objlist, link) { 3778 if (donelist_check(dlp, elm->obj)) 3779 continue; 3780 symlook_init_from_req(&req1, req); 3781 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 3782 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3783 def = req1.sym_out; 3784 defobj = req1.defobj_out; 3785 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3786 break; 3787 } 3788 } 3789 } 3790 if (def != NULL) { 3791 req->sym_out = def; 3792 req->defobj_out = defobj; 3793 return (0); 3794 } 3795 return (ESRCH); 3796} 3797 3798/* 3799 * Search the chain of DAGS cointed to by the given Needed_Entry 3800 * for a symbol of the given name. Each DAG is scanned completely 3801 * before advancing to the next one. Returns a pointer to the symbol, 3802 * or NULL if no definition was found. 3803 */ 3804static int 3805symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 3806{ 3807 const Elf_Sym *def; 3808 const Needed_Entry *n; 3809 const Obj_Entry *defobj; 3810 SymLook req1; 3811 int res; 3812 3813 def = NULL; 3814 defobj = NULL; 3815 symlook_init_from_req(&req1, req); 3816 for (n = needed; n != NULL; n = n->next) { 3817 if (n->obj == NULL || 3818 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 3819 continue; 3820 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3821 def = req1.sym_out; 3822 defobj = req1.defobj_out; 3823 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3824 break; 3825 } 3826 } 3827 if (def != NULL) { 3828 req->sym_out = def; 3829 req->defobj_out = defobj; 3830 return (0); 3831 } 3832 return (ESRCH); 3833} 3834 3835/* 3836 * Search the symbol table of a single shared object for a symbol of 3837 * the given name and version, if requested. Returns a pointer to the 3838 * symbol, or NULL if no definition was found. If the object is 3839 * filter, return filtered symbol from filtee. 3840 * 3841 * The symbol's hash value is passed in for efficiency reasons; that 3842 * eliminates many recomputations of the hash value. 3843 */ 3844int 3845symlook_obj(SymLook *req, const Obj_Entry *obj) 3846{ 3847 DoneList donelist; 3848 SymLook req1; 3849 int flags, res, mres; 3850 3851 /* 3852 * If there is at least one valid hash at this point, we prefer to 3853 * use the faster GNU version if available. 3854 */ 3855 if (obj->valid_hash_gnu) 3856 mres = symlook_obj1_gnu(req, obj); 3857 else if (obj->valid_hash_sysv) 3858 mres = symlook_obj1_sysv(req, obj); 3859 else 3860 return (EINVAL); 3861 3862 if (mres == 0) { 3863 if (obj->needed_filtees != NULL) { 3864 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3865 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3866 donelist_init(&donelist); 3867 symlook_init_from_req(&req1, req); 3868 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 3869 if (res == 0) { 3870 req->sym_out = req1.sym_out; 3871 req->defobj_out = req1.defobj_out; 3872 } 3873 return (res); 3874 } 3875 if (obj->needed_aux_filtees != NULL) { 3876 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3877 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3878 donelist_init(&donelist); 3879 symlook_init_from_req(&req1, req); 3880 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 3881 if (res == 0) { 3882 req->sym_out = req1.sym_out; 3883 req->defobj_out = req1.defobj_out; 3884 return (res); 3885 } 3886 } 3887 } 3888 return (mres); 3889} 3890 3891/* Symbol match routine common to both hash functions */ 3892static bool 3893matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 3894 const unsigned long symnum) 3895{ 3896 Elf_Versym verndx; 3897 const Elf_Sym *symp; 3898 const char *strp; 3899 3900 symp = obj->symtab + symnum; 3901 strp = obj->strtab + symp->st_name; 3902 3903 switch (ELF_ST_TYPE(symp->st_info)) { 3904 case STT_FUNC: 3905 case STT_NOTYPE: 3906 case STT_OBJECT: 3907 case STT_COMMON: 3908 case STT_GNU_IFUNC: 3909 if (symp->st_value == 0) 3910 return (false); 3911 /* fallthrough */ 3912 case STT_TLS: 3913 if (symp->st_shndx != SHN_UNDEF) 3914 break; 3915#ifndef __mips__ 3916 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 3917 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 3918 break; 3919 /* fallthrough */ 3920#endif 3921 default: 3922 return (false); 3923 } 3924 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 3925 return (false); 3926 3927 if (req->ventry == NULL) { 3928 if (obj->versyms != NULL) { 3929 verndx = VER_NDX(obj->versyms[symnum]); 3930 if (verndx > obj->vernum) { 3931 _rtld_error( 3932 "%s: symbol %s references wrong version %d", 3933 obj->path, obj->strtab + symnum, verndx); 3934 return (false); 3935 } 3936 /* 3937 * If we are not called from dlsym (i.e. this 3938 * is a normal relocation from unversioned 3939 * binary), accept the symbol immediately if 3940 * it happens to have first version after this 3941 * shared object became versioned. Otherwise, 3942 * if symbol is versioned and not hidden, 3943 * remember it. If it is the only symbol with 3944 * this name exported by the shared object, it 3945 * will be returned as a match by the calling 3946 * function. If symbol is global (verndx < 2) 3947 * accept it unconditionally. 3948 */ 3949 if ((req->flags & SYMLOOK_DLSYM) == 0 && 3950 verndx == VER_NDX_GIVEN) { 3951 result->sym_out = symp; 3952 return (true); 3953 } 3954 else if (verndx >= VER_NDX_GIVEN) { 3955 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 3956 == 0) { 3957 if (result->vsymp == NULL) 3958 result->vsymp = symp; 3959 result->vcount++; 3960 } 3961 return (false); 3962 } 3963 } 3964 result->sym_out = symp; 3965 return (true); 3966 } 3967 if (obj->versyms == NULL) { 3968 if (object_match_name(obj, req->ventry->name)) { 3969 _rtld_error("%s: object %s should provide version %s " 3970 "for symbol %s", obj_rtld.path, obj->path, 3971 req->ventry->name, obj->strtab + symnum); 3972 return (false); 3973 } 3974 } else { 3975 verndx = VER_NDX(obj->versyms[symnum]); 3976 if (verndx > obj->vernum) { 3977 _rtld_error("%s: symbol %s references wrong version %d", 3978 obj->path, obj->strtab + symnum, verndx); 3979 return (false); 3980 } 3981 if (obj->vertab[verndx].hash != req->ventry->hash || 3982 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 3983 /* 3984 * Version does not match. Look if this is a 3985 * global symbol and if it is not hidden. If 3986 * global symbol (verndx < 2) is available, 3987 * use it. Do not return symbol if we are 3988 * called by dlvsym, because dlvsym looks for 3989 * a specific version and default one is not 3990 * what dlvsym wants. 3991 */ 3992 if ((req->flags & SYMLOOK_DLSYM) || 3993 (verndx >= VER_NDX_GIVEN) || 3994 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 3995 return (false); 3996 } 3997 } 3998 result->sym_out = symp; 3999 return (true); 4000} 4001 4002/* 4003 * Search for symbol using SysV hash function. 4004 * obj->buckets is known not to be NULL at this point; the test for this was 4005 * performed with the obj->valid_hash_sysv assignment. 4006 */ 4007static int 4008symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4009{ 4010 unsigned long symnum; 4011 Sym_Match_Result matchres; 4012 4013 matchres.sym_out = NULL; 4014 matchres.vsymp = NULL; 4015 matchres.vcount = 0; 4016 4017 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4018 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4019 if (symnum >= obj->nchains) 4020 return (ESRCH); /* Bad object */ 4021 4022 if (matched_symbol(req, obj, &matchres, symnum)) { 4023 req->sym_out = matchres.sym_out; 4024 req->defobj_out = obj; 4025 return (0); 4026 } 4027 } 4028 if (matchres.vcount == 1) { 4029 req->sym_out = matchres.vsymp; 4030 req->defobj_out = obj; 4031 return (0); 4032 } 4033 return (ESRCH); 4034} 4035 4036/* Search for symbol using GNU hash function */ 4037static int 4038symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4039{ 4040 Elf_Addr bloom_word; 4041 const Elf32_Word *hashval; 4042 Elf32_Word bucket; 4043 Sym_Match_Result matchres; 4044 unsigned int h1, h2; 4045 unsigned long symnum; 4046 4047 matchres.sym_out = NULL; 4048 matchres.vsymp = NULL; 4049 matchres.vcount = 0; 4050 4051 /* Pick right bitmask word from Bloom filter array */ 4052 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4053 obj->maskwords_bm_gnu]; 4054 4055 /* Calculate modulus word size of gnu hash and its derivative */ 4056 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4057 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4058 4059 /* Filter out the "definitely not in set" queries */ 4060 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4061 return (ESRCH); 4062 4063 /* Locate hash chain and corresponding value element*/ 4064 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4065 if (bucket == 0) 4066 return (ESRCH); 4067 hashval = &obj->chain_zero_gnu[bucket]; 4068 do { 4069 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4070 symnum = hashval - obj->chain_zero_gnu; 4071 if (matched_symbol(req, obj, &matchres, symnum)) { 4072 req->sym_out = matchres.sym_out; 4073 req->defobj_out = obj; 4074 return (0); 4075 } 4076 } 4077 } while ((*hashval++ & 1) == 0); 4078 if (matchres.vcount == 1) { 4079 req->sym_out = matchres.vsymp; 4080 req->defobj_out = obj; 4081 return (0); 4082 } 4083 return (ESRCH); 4084} 4085 4086static void 4087trace_loaded_objects(Obj_Entry *obj) 4088{ 4089 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4090 int c; 4091 4092 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 4093 main_local = ""; 4094 4095 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL) 4096 fmt1 = "\t%o => %p (%x)\n"; 4097 4098 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL) 4099 fmt2 = "\t%o (%x)\n"; 4100 4101 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL"); 4102 4103 for (; obj; obj = obj->next) { 4104 Needed_Entry *needed; 4105 char *name, *path; 4106 bool is_lib; 4107 4108 if (list_containers && obj->needed != NULL) 4109 rtld_printf("%s:\n", obj->path); 4110 for (needed = obj->needed; needed; needed = needed->next) { 4111 if (needed->obj != NULL) { 4112 if (needed->obj->traced && !list_containers) 4113 continue; 4114 needed->obj->traced = true; 4115 path = needed->obj->path; 4116 } else 4117 path = "not found"; 4118 4119 name = (char *)obj->strtab + needed->name; 4120 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4121 4122 fmt = is_lib ? fmt1 : fmt2; 4123 while ((c = *fmt++) != '\0') { 4124 switch (c) { 4125 default: 4126 rtld_putchar(c); 4127 continue; 4128 case '\\': 4129 switch (c = *fmt) { 4130 case '\0': 4131 continue; 4132 case 'n': 4133 rtld_putchar('\n'); 4134 break; 4135 case 't': 4136 rtld_putchar('\t'); 4137 break; 4138 } 4139 break; 4140 case '%': 4141 switch (c = *fmt) { 4142 case '\0': 4143 continue; 4144 case '%': 4145 default: 4146 rtld_putchar(c); 4147 break; 4148 case 'A': 4149 rtld_putstr(main_local); 4150 break; 4151 case 'a': 4152 rtld_putstr(obj_main->path); 4153 break; 4154 case 'o': 4155 rtld_putstr(name); 4156 break; 4157#if 0 4158 case 'm': 4159 rtld_printf("%d", sodp->sod_major); 4160 break; 4161 case 'n': 4162 rtld_printf("%d", sodp->sod_minor); 4163 break; 4164#endif 4165 case 'p': 4166 rtld_putstr(path); 4167 break; 4168 case 'x': 4169 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4170 0); 4171 break; 4172 } 4173 break; 4174 } 4175 ++fmt; 4176 } 4177 } 4178 } 4179} 4180 4181/* 4182 * Unload a dlopened object and its dependencies from memory and from 4183 * our data structures. It is assumed that the DAG rooted in the 4184 * object has already been unreferenced, and that the object has a 4185 * reference count of 0. 4186 */ 4187static void 4188unload_object(Obj_Entry *root) 4189{ 4190 Obj_Entry *obj; 4191 Obj_Entry **linkp; 4192 4193 assert(root->refcount == 0); 4194 4195 /* 4196 * Pass over the DAG removing unreferenced objects from 4197 * appropriate lists. 4198 */ 4199 unlink_object(root); 4200 4201 /* Unmap all objects that are no longer referenced. */ 4202 linkp = &obj_list->next; 4203 while ((obj = *linkp) != NULL) { 4204 if (obj->refcount == 0) { 4205 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 4206 obj->path); 4207 dbg("unloading \"%s\"", obj->path); 4208 unload_filtees(root); 4209 munmap(obj->mapbase, obj->mapsize); 4210 linkmap_delete(obj); 4211 *linkp = obj->next; 4212 obj_count--; 4213 obj_free(obj); 4214 } else 4215 linkp = &obj->next; 4216 } 4217 obj_tail = linkp; 4218} 4219 4220static void 4221unlink_object(Obj_Entry *root) 4222{ 4223 Objlist_Entry *elm; 4224 4225 if (root->refcount == 0) { 4226 /* Remove the object from the RTLD_GLOBAL list. */ 4227 objlist_remove(&list_global, root); 4228 4229 /* Remove the object from all objects' DAG lists. */ 4230 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4231 objlist_remove(&elm->obj->dldags, root); 4232 if (elm->obj != root) 4233 unlink_object(elm->obj); 4234 } 4235 } 4236} 4237 4238static void 4239ref_dag(Obj_Entry *root) 4240{ 4241 Objlist_Entry *elm; 4242 4243 assert(root->dag_inited); 4244 STAILQ_FOREACH(elm, &root->dagmembers, link) 4245 elm->obj->refcount++; 4246} 4247 4248static void 4249unref_dag(Obj_Entry *root) 4250{ 4251 Objlist_Entry *elm; 4252 4253 assert(root->dag_inited); 4254 STAILQ_FOREACH(elm, &root->dagmembers, link) 4255 elm->obj->refcount--; 4256} 4257 4258/* 4259 * Common code for MD __tls_get_addr(). 4260 */ 4261static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4262static void * 4263tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4264{ 4265 Elf_Addr *newdtv, *dtv; 4266 RtldLockState lockstate; 4267 int to_copy; 4268 4269 dtv = *dtvp; 4270 /* Check dtv generation in case new modules have arrived */ 4271 if (dtv[0] != tls_dtv_generation) { 4272 wlock_acquire(rtld_bind_lock, &lockstate); 4273 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4274 to_copy = dtv[1]; 4275 if (to_copy > tls_max_index) 4276 to_copy = tls_max_index; 4277 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4278 newdtv[0] = tls_dtv_generation; 4279 newdtv[1] = tls_max_index; 4280 free(dtv); 4281 lock_release(rtld_bind_lock, &lockstate); 4282 dtv = *dtvp = newdtv; 4283 } 4284 4285 /* Dynamically allocate module TLS if necessary */ 4286 if (dtv[index + 1] == 0) { 4287 /* Signal safe, wlock will block out signals. */ 4288 wlock_acquire(rtld_bind_lock, &lockstate); 4289 if (!dtv[index + 1]) 4290 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4291 lock_release(rtld_bind_lock, &lockstate); 4292 } 4293 return ((void *)(dtv[index + 1] + offset)); 4294} 4295 4296void * 4297tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4298{ 4299 Elf_Addr *dtv; 4300 4301 dtv = *dtvp; 4302 /* Check dtv generation in case new modules have arrived */ 4303 if (__predict_true(dtv[0] == tls_dtv_generation && 4304 dtv[index + 1] != 0)) 4305 return ((void *)(dtv[index + 1] + offset)); 4306 return (tls_get_addr_slow(dtvp, index, offset)); 4307} 4308 4309#if defined(__arm__) || defined(__ia64__) || defined(__mips__) || defined(__powerpc__) 4310 4311/* 4312 * Allocate Static TLS using the Variant I method. 4313 */ 4314void * 4315allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4316{ 4317 Obj_Entry *obj; 4318 char *tcb; 4319 Elf_Addr **tls; 4320 Elf_Addr *dtv; 4321 Elf_Addr addr; 4322 int i; 4323 4324 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4325 return (oldtcb); 4326 4327 assert(tcbsize >= TLS_TCB_SIZE); 4328 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 4329 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 4330 4331 if (oldtcb != NULL) { 4332 memcpy(tls, oldtcb, tls_static_space); 4333 free(oldtcb); 4334 4335 /* Adjust the DTV. */ 4336 dtv = tls[0]; 4337 for (i = 0; i < dtv[1]; i++) { 4338 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4339 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4340 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 4341 } 4342 } 4343 } else { 4344 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4345 tls[0] = dtv; 4346 dtv[0] = tls_dtv_generation; 4347 dtv[1] = tls_max_index; 4348 4349 for (obj = objs; obj; obj = obj->next) { 4350 if (obj->tlsoffset > 0) { 4351 addr = (Elf_Addr)tls + obj->tlsoffset; 4352 if (obj->tlsinitsize > 0) 4353 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4354 if (obj->tlssize > obj->tlsinitsize) 4355 memset((void*) (addr + obj->tlsinitsize), 0, 4356 obj->tlssize - obj->tlsinitsize); 4357 dtv[obj->tlsindex + 1] = addr; 4358 } 4359 } 4360 } 4361 4362 return (tcb); 4363} 4364 4365void 4366free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4367{ 4368 Elf_Addr *dtv; 4369 Elf_Addr tlsstart, tlsend; 4370 int dtvsize, i; 4371 4372 assert(tcbsize >= TLS_TCB_SIZE); 4373 4374 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 4375 tlsend = tlsstart + tls_static_space; 4376 4377 dtv = *(Elf_Addr **)tlsstart; 4378 dtvsize = dtv[1]; 4379 for (i = 0; i < dtvsize; i++) { 4380 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4381 free((void*)dtv[i+2]); 4382 } 4383 } 4384 free(dtv); 4385 free(tcb); 4386} 4387 4388#endif 4389 4390#if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 4391 4392/* 4393 * Allocate Static TLS using the Variant II method. 4394 */ 4395void * 4396allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4397{ 4398 Obj_Entry *obj; 4399 size_t size, ralign; 4400 char *tls; 4401 Elf_Addr *dtv, *olddtv; 4402 Elf_Addr segbase, oldsegbase, addr; 4403 int i; 4404 4405 ralign = tcbalign; 4406 if (tls_static_max_align > ralign) 4407 ralign = tls_static_max_align; 4408 size = round(tls_static_space, ralign) + round(tcbsize, ralign); 4409 4410 assert(tcbsize >= 2*sizeof(Elf_Addr)); 4411 tls = malloc_aligned(size, ralign); 4412 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4413 4414 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign)); 4415 ((Elf_Addr*)segbase)[0] = segbase; 4416 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 4417 4418 dtv[0] = tls_dtv_generation; 4419 dtv[1] = tls_max_index; 4420 4421 if (oldtls) { 4422 /* 4423 * Copy the static TLS block over whole. 4424 */ 4425 oldsegbase = (Elf_Addr) oldtls; 4426 memcpy((void *)(segbase - tls_static_space), 4427 (const void *)(oldsegbase - tls_static_space), 4428 tls_static_space); 4429 4430 /* 4431 * If any dynamic TLS blocks have been created tls_get_addr(), 4432 * move them over. 4433 */ 4434 olddtv = ((Elf_Addr**)oldsegbase)[1]; 4435 for (i = 0; i < olddtv[1]; i++) { 4436 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 4437 dtv[i+2] = olddtv[i+2]; 4438 olddtv[i+2] = 0; 4439 } 4440 } 4441 4442 /* 4443 * We assume that this block was the one we created with 4444 * allocate_initial_tls(). 4445 */ 4446 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 4447 } else { 4448 for (obj = objs; obj; obj = obj->next) { 4449 if (obj->tlsoffset) { 4450 addr = segbase - obj->tlsoffset; 4451 memset((void*) (addr + obj->tlsinitsize), 4452 0, obj->tlssize - obj->tlsinitsize); 4453 if (obj->tlsinit) 4454 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4455 dtv[obj->tlsindex + 1] = addr; 4456 } 4457 } 4458 } 4459 4460 return (void*) segbase; 4461} 4462 4463void 4464free_tls(void *tls, size_t tcbsize, size_t tcbalign) 4465{ 4466 Elf_Addr* dtv; 4467 size_t size, ralign; 4468 int dtvsize, i; 4469 Elf_Addr tlsstart, tlsend; 4470 4471 /* 4472 * Figure out the size of the initial TLS block so that we can 4473 * find stuff which ___tls_get_addr() allocated dynamically. 4474 */ 4475 ralign = tcbalign; 4476 if (tls_static_max_align > ralign) 4477 ralign = tls_static_max_align; 4478 size = round(tls_static_space, ralign); 4479 4480 dtv = ((Elf_Addr**)tls)[1]; 4481 dtvsize = dtv[1]; 4482 tlsend = (Elf_Addr) tls; 4483 tlsstart = tlsend - size; 4484 for (i = 0; i < dtvsize; i++) { 4485 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 4486 free_aligned((void *)dtv[i + 2]); 4487 } 4488 } 4489 4490 free_aligned((void *)tlsstart); 4491 free((void*) dtv); 4492} 4493 4494#endif 4495 4496/* 4497 * Allocate TLS block for module with given index. 4498 */ 4499void * 4500allocate_module_tls(int index) 4501{ 4502 Obj_Entry* obj; 4503 char* p; 4504 4505 for (obj = obj_list; obj; obj = obj->next) { 4506 if (obj->tlsindex == index) 4507 break; 4508 } 4509 if (!obj) { 4510 _rtld_error("Can't find module with TLS index %d", index); 4511 rtld_die(); 4512 } 4513 4514 p = malloc_aligned(obj->tlssize, obj->tlsalign); 4515 memcpy(p, obj->tlsinit, obj->tlsinitsize); 4516 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 4517 4518 return p; 4519} 4520 4521bool 4522allocate_tls_offset(Obj_Entry *obj) 4523{ 4524 size_t off; 4525 4526 if (obj->tls_done) 4527 return true; 4528 4529 if (obj->tlssize == 0) { 4530 obj->tls_done = true; 4531 return true; 4532 } 4533 4534 if (tls_last_offset == 0) 4535 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 4536 else 4537 off = calculate_tls_offset(tls_last_offset, tls_last_size, 4538 obj->tlssize, obj->tlsalign); 4539 4540 /* 4541 * If we have already fixed the size of the static TLS block, we 4542 * must stay within that size. When allocating the static TLS, we 4543 * leave a small amount of space spare to be used for dynamically 4544 * loading modules which use static TLS. 4545 */ 4546 if (tls_static_space != 0) { 4547 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 4548 return false; 4549 } else if (obj->tlsalign > tls_static_max_align) { 4550 tls_static_max_align = obj->tlsalign; 4551 } 4552 4553 tls_last_offset = obj->tlsoffset = off; 4554 tls_last_size = obj->tlssize; 4555 obj->tls_done = true; 4556 4557 return true; 4558} 4559 4560void 4561free_tls_offset(Obj_Entry *obj) 4562{ 4563 4564 /* 4565 * If we were the last thing to allocate out of the static TLS 4566 * block, we give our space back to the 'allocator'. This is a 4567 * simplistic workaround to allow libGL.so.1 to be loaded and 4568 * unloaded multiple times. 4569 */ 4570 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 4571 == calculate_tls_end(tls_last_offset, tls_last_size)) { 4572 tls_last_offset -= obj->tlssize; 4573 tls_last_size = 0; 4574 } 4575} 4576 4577void * 4578_rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 4579{ 4580 void *ret; 4581 RtldLockState lockstate; 4582 4583 wlock_acquire(rtld_bind_lock, &lockstate); 4584 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign); 4585 lock_release(rtld_bind_lock, &lockstate); 4586 return (ret); 4587} 4588 4589void 4590_rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4591{ 4592 RtldLockState lockstate; 4593 4594 wlock_acquire(rtld_bind_lock, &lockstate); 4595 free_tls(tcb, tcbsize, tcbalign); 4596 lock_release(rtld_bind_lock, &lockstate); 4597} 4598 4599static void 4600object_add_name(Obj_Entry *obj, const char *name) 4601{ 4602 Name_Entry *entry; 4603 size_t len; 4604 4605 len = strlen(name); 4606 entry = malloc(sizeof(Name_Entry) + len); 4607 4608 if (entry != NULL) { 4609 strcpy(entry->name, name); 4610 STAILQ_INSERT_TAIL(&obj->names, entry, link); 4611 } 4612} 4613 4614static int 4615object_match_name(const Obj_Entry *obj, const char *name) 4616{ 4617 Name_Entry *entry; 4618 4619 STAILQ_FOREACH(entry, &obj->names, link) { 4620 if (strcmp(name, entry->name) == 0) 4621 return (1); 4622 } 4623 return (0); 4624} 4625 4626static Obj_Entry * 4627locate_dependency(const Obj_Entry *obj, const char *name) 4628{ 4629 const Objlist_Entry *entry; 4630 const Needed_Entry *needed; 4631 4632 STAILQ_FOREACH(entry, &list_main, link) { 4633 if (object_match_name(entry->obj, name)) 4634 return entry->obj; 4635 } 4636 4637 for (needed = obj->needed; needed != NULL; needed = needed->next) { 4638 if (strcmp(obj->strtab + needed->name, name) == 0 || 4639 (needed->obj != NULL && object_match_name(needed->obj, name))) { 4640 /* 4641 * If there is DT_NEEDED for the name we are looking for, 4642 * we are all set. Note that object might not be found if 4643 * dependency was not loaded yet, so the function can 4644 * return NULL here. This is expected and handled 4645 * properly by the caller. 4646 */ 4647 return (needed->obj); 4648 } 4649 } 4650 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 4651 obj->path, name); 4652 rtld_die(); 4653} 4654 4655static int 4656check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 4657 const Elf_Vernaux *vna) 4658{ 4659 const Elf_Verdef *vd; 4660 const char *vername; 4661 4662 vername = refobj->strtab + vna->vna_name; 4663 vd = depobj->verdef; 4664 if (vd == NULL) { 4665 _rtld_error("%s: version %s required by %s not defined", 4666 depobj->path, vername, refobj->path); 4667 return (-1); 4668 } 4669 for (;;) { 4670 if (vd->vd_version != VER_DEF_CURRENT) { 4671 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4672 depobj->path, vd->vd_version); 4673 return (-1); 4674 } 4675 if (vna->vna_hash == vd->vd_hash) { 4676 const Elf_Verdaux *aux = (const Elf_Verdaux *) 4677 ((char *)vd + vd->vd_aux); 4678 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 4679 return (0); 4680 } 4681 if (vd->vd_next == 0) 4682 break; 4683 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4684 } 4685 if (vna->vna_flags & VER_FLG_WEAK) 4686 return (0); 4687 _rtld_error("%s: version %s required by %s not found", 4688 depobj->path, vername, refobj->path); 4689 return (-1); 4690} 4691 4692static int 4693rtld_verify_object_versions(Obj_Entry *obj) 4694{ 4695 const Elf_Verneed *vn; 4696 const Elf_Verdef *vd; 4697 const Elf_Verdaux *vda; 4698 const Elf_Vernaux *vna; 4699 const Obj_Entry *depobj; 4700 int maxvernum, vernum; 4701 4702 if (obj->ver_checked) 4703 return (0); 4704 obj->ver_checked = true; 4705 4706 maxvernum = 0; 4707 /* 4708 * Walk over defined and required version records and figure out 4709 * max index used by any of them. Do very basic sanity checking 4710 * while there. 4711 */ 4712 vn = obj->verneed; 4713 while (vn != NULL) { 4714 if (vn->vn_version != VER_NEED_CURRENT) { 4715 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 4716 obj->path, vn->vn_version); 4717 return (-1); 4718 } 4719 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4720 for (;;) { 4721 vernum = VER_NEED_IDX(vna->vna_other); 4722 if (vernum > maxvernum) 4723 maxvernum = vernum; 4724 if (vna->vna_next == 0) 4725 break; 4726 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4727 } 4728 if (vn->vn_next == 0) 4729 break; 4730 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4731 } 4732 4733 vd = obj->verdef; 4734 while (vd != NULL) { 4735 if (vd->vd_version != VER_DEF_CURRENT) { 4736 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4737 obj->path, vd->vd_version); 4738 return (-1); 4739 } 4740 vernum = VER_DEF_IDX(vd->vd_ndx); 4741 if (vernum > maxvernum) 4742 maxvernum = vernum; 4743 if (vd->vd_next == 0) 4744 break; 4745 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4746 } 4747 4748 if (maxvernum == 0) 4749 return (0); 4750 4751 /* 4752 * Store version information in array indexable by version index. 4753 * Verify that object version requirements are satisfied along the 4754 * way. 4755 */ 4756 obj->vernum = maxvernum + 1; 4757 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 4758 4759 vd = obj->verdef; 4760 while (vd != NULL) { 4761 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 4762 vernum = VER_DEF_IDX(vd->vd_ndx); 4763 assert(vernum <= maxvernum); 4764 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 4765 obj->vertab[vernum].hash = vd->vd_hash; 4766 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 4767 obj->vertab[vernum].file = NULL; 4768 obj->vertab[vernum].flags = 0; 4769 } 4770 if (vd->vd_next == 0) 4771 break; 4772 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4773 } 4774 4775 vn = obj->verneed; 4776 while (vn != NULL) { 4777 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 4778 if (depobj == NULL) 4779 return (-1); 4780 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4781 for (;;) { 4782 if (check_object_provided_version(obj, depobj, vna)) 4783 return (-1); 4784 vernum = VER_NEED_IDX(vna->vna_other); 4785 assert(vernum <= maxvernum); 4786 obj->vertab[vernum].hash = vna->vna_hash; 4787 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 4788 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 4789 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 4790 VER_INFO_HIDDEN : 0; 4791 if (vna->vna_next == 0) 4792 break; 4793 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4794 } 4795 if (vn->vn_next == 0) 4796 break; 4797 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4798 } 4799 return 0; 4800} 4801 4802static int 4803rtld_verify_versions(const Objlist *objlist) 4804{ 4805 Objlist_Entry *entry; 4806 int rc; 4807 4808 rc = 0; 4809 STAILQ_FOREACH(entry, objlist, link) { 4810 /* 4811 * Skip dummy objects or objects that have their version requirements 4812 * already checked. 4813 */ 4814 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 4815 continue; 4816 if (rtld_verify_object_versions(entry->obj) == -1) { 4817 rc = -1; 4818 if (ld_tracing == NULL) 4819 break; 4820 } 4821 } 4822 if (rc == 0 || ld_tracing != NULL) 4823 rc = rtld_verify_object_versions(&obj_rtld); 4824 return rc; 4825} 4826 4827const Ver_Entry * 4828fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 4829{ 4830 Elf_Versym vernum; 4831 4832 if (obj->vertab) { 4833 vernum = VER_NDX(obj->versyms[symnum]); 4834 if (vernum >= obj->vernum) { 4835 _rtld_error("%s: symbol %s has wrong verneed value %d", 4836 obj->path, obj->strtab + symnum, vernum); 4837 } else if (obj->vertab[vernum].hash != 0) { 4838 return &obj->vertab[vernum]; 4839 } 4840 } 4841 return NULL; 4842} 4843 4844int 4845_rtld_get_stack_prot(void) 4846{ 4847 4848 return (stack_prot); 4849} 4850 4851int 4852_rtld_is_dlopened(void *arg) 4853{ 4854 Obj_Entry *obj; 4855 RtldLockState lockstate; 4856 int res; 4857 4858 rlock_acquire(rtld_bind_lock, &lockstate); 4859 obj = dlcheck(arg); 4860 if (obj == NULL) 4861 obj = obj_from_addr(arg); 4862 if (obj == NULL) { 4863 _rtld_error("No shared object contains address"); 4864 lock_release(rtld_bind_lock, &lockstate); 4865 return (-1); 4866 } 4867 res = obj->dlopened ? 1 : 0; 4868 lock_release(rtld_bind_lock, &lockstate); 4869 return (res); 4870} 4871 4872static void 4873map_stacks_exec(RtldLockState *lockstate) 4874{ 4875 void (*thr_map_stacks_exec)(void); 4876 4877 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 4878 return; 4879 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 4880 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 4881 if (thr_map_stacks_exec != NULL) { 4882 stack_prot |= PROT_EXEC; 4883 thr_map_stacks_exec(); 4884 } 4885} 4886 4887void 4888symlook_init(SymLook *dst, const char *name) 4889{ 4890 4891 bzero(dst, sizeof(*dst)); 4892 dst->name = name; 4893 dst->hash = elf_hash(name); 4894 dst->hash_gnu = gnu_hash(name); 4895} 4896 4897static void 4898symlook_init_from_req(SymLook *dst, const SymLook *src) 4899{ 4900 4901 dst->name = src->name; 4902 dst->hash = src->hash; 4903 dst->hash_gnu = src->hash_gnu; 4904 dst->ventry = src->ventry; 4905 dst->flags = src->flags; 4906 dst->defobj_out = NULL; 4907 dst->sym_out = NULL; 4908 dst->lockstate = src->lockstate; 4909} 4910 4911/* 4912 * Overrides for libc_pic-provided functions. 4913 */ 4914 4915int 4916__getosreldate(void) 4917{ 4918 size_t len; 4919 int oid[2]; 4920 int error, osrel; 4921 4922 if (osreldate != 0) 4923 return (osreldate); 4924 4925 oid[0] = CTL_KERN; 4926 oid[1] = KERN_OSRELDATE; 4927 osrel = 0; 4928 len = sizeof(osrel); 4929 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 4930 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 4931 osreldate = osrel; 4932 return (osreldate); 4933} 4934 4935void 4936exit(int status) 4937{ 4938 4939 _exit(status); 4940} 4941 4942void (*__cleanup)(void); 4943int __isthreaded = 0; 4944int _thread_autoinit_dummy_decl = 1; 4945 4946/* 4947 * No unresolved symbols for rtld. 4948 */ 4949void 4950__pthread_cxa_finalize(struct dl_phdr_info *a) 4951{ 4952} 4953 4954void 4955__stack_chk_fail(void) 4956{ 4957 4958 _rtld_error("stack overflow detected; terminated"); 4959 rtld_die(); 4960} 4961__weak_reference(__stack_chk_fail, __stack_chk_fail_local); 4962 4963void 4964__chk_fail(void) 4965{ 4966 4967 _rtld_error("buffer overflow detected; terminated"); 4968 rtld_die(); 4969} 4970 4971const char * 4972rtld_strerror(int errnum) 4973{ 4974 4975 if (errnum < 0 || errnum >= sys_nerr) 4976 return ("Unknown error"); 4977 return (sys_errlist[errnum]); 4978} 4979