rtld.c revision 287331
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 287331 2015-08-31 19:20:18Z 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 /* XXX - not implemented yet */ 1119 if (!early) 1120 dbg("Filling in DT_DEBUG entry"); 1121 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 1122 break; 1123#endif 1124 1125 case DT_FLAGS: 1126 if (dynp->d_un.d_val & DF_ORIGIN) 1127 obj->z_origin = true; 1128 if (dynp->d_un.d_val & DF_SYMBOLIC) 1129 obj->symbolic = true; 1130 if (dynp->d_un.d_val & DF_TEXTREL) 1131 obj->textrel = true; 1132 if (dynp->d_un.d_val & DF_BIND_NOW) 1133 obj->bind_now = true; 1134 /*if (dynp->d_un.d_val & DF_STATIC_TLS) 1135 ;*/ 1136 break; 1137#ifdef __mips__ 1138 case DT_MIPS_LOCAL_GOTNO: 1139 obj->local_gotno = dynp->d_un.d_val; 1140 break; 1141 1142 case DT_MIPS_SYMTABNO: 1143 obj->symtabno = dynp->d_un.d_val; 1144 break; 1145 1146 case DT_MIPS_GOTSYM: 1147 obj->gotsym = dynp->d_un.d_val; 1148 break; 1149 1150 case DT_MIPS_RLD_MAP: 1151 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1152 break; 1153#endif 1154 1155 case DT_FLAGS_1: 1156 if (dynp->d_un.d_val & DF_1_NOOPEN) 1157 obj->z_noopen = true; 1158 if (dynp->d_un.d_val & DF_1_ORIGIN) 1159 obj->z_origin = true; 1160 if (dynp->d_un.d_val & DF_1_GLOBAL) 1161 obj->z_global = true; 1162 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1163 obj->bind_now = true; 1164 if (dynp->d_un.d_val & DF_1_NODELETE) 1165 obj->z_nodelete = true; 1166 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1167 obj->z_loadfltr = true; 1168 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1169 obj->z_interpose = true; 1170 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1171 obj->z_nodeflib = true; 1172 break; 1173 1174 default: 1175 if (!early) { 1176 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1177 (long)dynp->d_tag); 1178 } 1179 break; 1180 } 1181 } 1182 1183 obj->traced = false; 1184 1185 if (plttype == DT_RELA) { 1186 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1187 obj->pltrel = NULL; 1188 obj->pltrelasize = obj->pltrelsize; 1189 obj->pltrelsize = 0; 1190 } 1191 1192 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1193 if (obj->valid_hash_sysv) 1194 obj->dynsymcount = obj->nchains; 1195 else if (obj->valid_hash_gnu) { 1196 obj->dynsymcount = 0; 1197 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1198 if (obj->buckets_gnu[bkt] == 0) 1199 continue; 1200 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1201 do 1202 obj->dynsymcount++; 1203 while ((*hashval++ & 1u) == 0); 1204 } 1205 obj->dynsymcount += obj->symndx_gnu; 1206 } 1207} 1208 1209static bool 1210obj_resolve_origin(Obj_Entry *obj) 1211{ 1212 1213 if (obj->origin_path != NULL) 1214 return (true); 1215 obj->origin_path = xmalloc(PATH_MAX); 1216 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1); 1217} 1218 1219static void 1220digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1221 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1222{ 1223 1224 if (obj->z_origin && !obj_resolve_origin(obj)) 1225 rtld_die(); 1226 1227 if (dyn_runpath != NULL) { 1228 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val; 1229 obj->runpath = origin_subst(obj, obj->runpath); 1230 } else if (dyn_rpath != NULL) { 1231 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 1232 obj->rpath = origin_subst(obj, obj->rpath); 1233 } 1234 if (dyn_soname != NULL) 1235 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1236} 1237 1238static void 1239digest_dynamic(Obj_Entry *obj, int early) 1240{ 1241 const Elf_Dyn *dyn_rpath; 1242 const Elf_Dyn *dyn_soname; 1243 const Elf_Dyn *dyn_runpath; 1244 1245 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1246 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath); 1247} 1248 1249/* 1250 * Process a shared object's program header. This is used only for the 1251 * main program, when the kernel has already loaded the main program 1252 * into memory before calling the dynamic linker. It creates and 1253 * returns an Obj_Entry structure. 1254 */ 1255static Obj_Entry * 1256digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1257{ 1258 Obj_Entry *obj; 1259 const Elf_Phdr *phlimit = phdr + phnum; 1260 const Elf_Phdr *ph; 1261 Elf_Addr note_start, note_end; 1262 int nsegs = 0; 1263 1264 obj = obj_new(); 1265 for (ph = phdr; ph < phlimit; ph++) { 1266 if (ph->p_type != PT_PHDR) 1267 continue; 1268 1269 obj->phdr = phdr; 1270 obj->phsize = ph->p_memsz; 1271 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1272 break; 1273 } 1274 1275 obj->stack_flags = PF_X | PF_R | PF_W; 1276 1277 for (ph = phdr; ph < phlimit; ph++) { 1278 switch (ph->p_type) { 1279 1280 case PT_INTERP: 1281 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1282 break; 1283 1284 case PT_LOAD: 1285 if (nsegs == 0) { /* First load segment */ 1286 obj->vaddrbase = trunc_page(ph->p_vaddr); 1287 obj->mapbase = obj->vaddrbase + obj->relocbase; 1288 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1289 obj->vaddrbase; 1290 } else { /* Last load segment */ 1291 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1292 obj->vaddrbase; 1293 } 1294 nsegs++; 1295 break; 1296 1297 case PT_DYNAMIC: 1298 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1299 break; 1300 1301 case PT_TLS: 1302 obj->tlsindex = 1; 1303 obj->tlssize = ph->p_memsz; 1304 obj->tlsalign = ph->p_align; 1305 obj->tlsinitsize = ph->p_filesz; 1306 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1307 break; 1308 1309 case PT_GNU_STACK: 1310 obj->stack_flags = ph->p_flags; 1311 break; 1312 1313 case PT_GNU_RELRO: 1314 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1315 obj->relro_size = round_page(ph->p_memsz); 1316 break; 1317 1318 case PT_NOTE: 1319 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1320 note_end = note_start + ph->p_filesz; 1321 digest_notes(obj, note_start, note_end); 1322 break; 1323 } 1324 } 1325 if (nsegs < 1) { 1326 _rtld_error("%s: too few PT_LOAD segments", path); 1327 return NULL; 1328 } 1329 1330 obj->entry = entry; 1331 return obj; 1332} 1333 1334void 1335digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1336{ 1337 const Elf_Note *note; 1338 const char *note_name; 1339 uintptr_t p; 1340 1341 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1342 note = (const Elf_Note *)((const char *)(note + 1) + 1343 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1344 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1345 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1346 note->n_descsz != sizeof(int32_t)) 1347 continue; 1348 if (note->n_type != ABI_NOTETYPE && 1349 note->n_type != CRT_NOINIT_NOTETYPE) 1350 continue; 1351 note_name = (const char *)(note + 1); 1352 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1353 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1354 continue; 1355 switch (note->n_type) { 1356 case ABI_NOTETYPE: 1357 /* FreeBSD osrel note */ 1358 p = (uintptr_t)(note + 1); 1359 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1360 obj->osrel = *(const int32_t *)(p); 1361 dbg("note osrel %d", obj->osrel); 1362 break; 1363 case CRT_NOINIT_NOTETYPE: 1364 /* FreeBSD 'crt does not call init' note */ 1365 obj->crt_no_init = true; 1366 dbg("note crt_no_init"); 1367 break; 1368 } 1369 } 1370} 1371 1372static Obj_Entry * 1373dlcheck(void *handle) 1374{ 1375 Obj_Entry *obj; 1376 1377 for (obj = obj_list; obj != NULL; obj = obj->next) 1378 if (obj == (Obj_Entry *) handle) 1379 break; 1380 1381 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1382 _rtld_error("Invalid shared object handle %p", handle); 1383 return NULL; 1384 } 1385 return obj; 1386} 1387 1388/* 1389 * If the given object is already in the donelist, return true. Otherwise 1390 * add the object to the list and return false. 1391 */ 1392static bool 1393donelist_check(DoneList *dlp, const Obj_Entry *obj) 1394{ 1395 unsigned int i; 1396 1397 for (i = 0; i < dlp->num_used; i++) 1398 if (dlp->objs[i] == obj) 1399 return true; 1400 /* 1401 * Our donelist allocation should always be sufficient. But if 1402 * our threads locking isn't working properly, more shared objects 1403 * could have been loaded since we allocated the list. That should 1404 * never happen, but we'll handle it properly just in case it does. 1405 */ 1406 if (dlp->num_used < dlp->num_alloc) 1407 dlp->objs[dlp->num_used++] = obj; 1408 return false; 1409} 1410 1411/* 1412 * Hash function for symbol table lookup. Don't even think about changing 1413 * this. It is specified by the System V ABI. 1414 */ 1415unsigned long 1416elf_hash(const char *name) 1417{ 1418 const unsigned char *p = (const unsigned char *) name; 1419 unsigned long h = 0; 1420 unsigned long g; 1421 1422 while (*p != '\0') { 1423 h = (h << 4) + *p++; 1424 if ((g = h & 0xf0000000) != 0) 1425 h ^= g >> 24; 1426 h &= ~g; 1427 } 1428 return h; 1429} 1430 1431/* 1432 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1433 * unsigned in case it's implemented with a wider type. 1434 */ 1435static uint32_t 1436gnu_hash(const char *s) 1437{ 1438 uint32_t h; 1439 unsigned char c; 1440 1441 h = 5381; 1442 for (c = *s; c != '\0'; c = *++s) 1443 h = h * 33 + c; 1444 return (h & 0xffffffff); 1445} 1446 1447/* 1448 * Find the library with the given name, and return its full pathname. 1449 * The returned string is dynamically allocated. Generates an error 1450 * message and returns NULL if the library cannot be found. 1451 * 1452 * If the second argument is non-NULL, then it refers to an already- 1453 * loaded shared object, whose library search path will be searched. 1454 * 1455 * The search order is: 1456 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1457 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1458 * LD_LIBRARY_PATH 1459 * DT_RUNPATH in the referencing file 1460 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1461 * from list) 1462 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1463 * 1464 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1465 */ 1466static char * 1467find_library(const char *xname, const Obj_Entry *refobj) 1468{ 1469 char *pathname; 1470 char *name; 1471 bool nodeflib, objgiven; 1472 1473 objgiven = refobj != NULL; 1474 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */ 1475 if (xname[0] != '/' && !trust) { 1476 _rtld_error("Absolute pathname required for shared object \"%s\"", 1477 xname); 1478 return NULL; 1479 } 1480 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1481 __DECONST(char *, xname))); 1482 } 1483 1484 if (libmap_disable || !objgiven || 1485 (name = lm_find(refobj->path, xname)) == NULL) 1486 name = (char *)xname; 1487 1488 dbg(" Searching for \"%s\"", name); 1489 1490 /* 1491 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1492 * back to pre-conforming behaviour if user requested so with 1493 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1494 * nodeflib. 1495 */ 1496 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1497 if ((pathname = search_library_path(name, ld_library_path)) != NULL || 1498 (refobj != NULL && 1499 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1500 (pathname = search_library_path(name, gethints(false))) != NULL || 1501 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL) 1502 return (pathname); 1503 } else { 1504 nodeflib = objgiven ? refobj->z_nodeflib : false; 1505 if ((objgiven && 1506 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1507 (objgiven && refobj->runpath == NULL && refobj != obj_main && 1508 (pathname = search_library_path(name, obj_main->rpath)) != NULL) || 1509 (pathname = search_library_path(name, ld_library_path)) != NULL || 1510 (objgiven && 1511 (pathname = search_library_path(name, refobj->runpath)) != NULL) || 1512 (pathname = search_library_path(name, gethints(nodeflib))) != NULL || 1513 (objgiven && !nodeflib && 1514 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)) 1515 return (pathname); 1516 } 1517 1518 if (objgiven && refobj->path != NULL) { 1519 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 1520 name, basename(refobj->path)); 1521 } else { 1522 _rtld_error("Shared object \"%s\" not found", name); 1523 } 1524 return NULL; 1525} 1526 1527/* 1528 * Given a symbol number in a referencing object, find the corresponding 1529 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1530 * no definition was found. Returns a pointer to the Obj_Entry of the 1531 * defining object via the reference parameter DEFOBJ_OUT. 1532 */ 1533const Elf_Sym * 1534find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1535 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1536 RtldLockState *lockstate) 1537{ 1538 const Elf_Sym *ref; 1539 const Elf_Sym *def; 1540 const Obj_Entry *defobj; 1541 SymLook req; 1542 const char *name; 1543 int res; 1544 1545 /* 1546 * If we have already found this symbol, get the information from 1547 * the cache. 1548 */ 1549 if (symnum >= refobj->dynsymcount) 1550 return NULL; /* Bad object */ 1551 if (cache != NULL && cache[symnum].sym != NULL) { 1552 *defobj_out = cache[symnum].obj; 1553 return cache[symnum].sym; 1554 } 1555 1556 ref = refobj->symtab + symnum; 1557 name = refobj->strtab + ref->st_name; 1558 def = NULL; 1559 defobj = NULL; 1560 1561 /* 1562 * We don't have to do a full scale lookup if the symbol is local. 1563 * We know it will bind to the instance in this load module; to 1564 * which we already have a pointer (ie ref). By not doing a lookup, 1565 * we not only improve performance, but it also avoids unresolvable 1566 * symbols when local symbols are not in the hash table. This has 1567 * been seen with the ia64 toolchain. 1568 */ 1569 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1570 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1571 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1572 symnum); 1573 } 1574 symlook_init(&req, name); 1575 req.flags = flags; 1576 req.ventry = fetch_ventry(refobj, symnum); 1577 req.lockstate = lockstate; 1578 res = symlook_default(&req, refobj); 1579 if (res == 0) { 1580 def = req.sym_out; 1581 defobj = req.defobj_out; 1582 } 1583 } else { 1584 def = ref; 1585 defobj = refobj; 1586 } 1587 1588 /* 1589 * If we found no definition and the reference is weak, treat the 1590 * symbol as having the value zero. 1591 */ 1592 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1593 def = &sym_zero; 1594 defobj = obj_main; 1595 } 1596 1597 if (def != NULL) { 1598 *defobj_out = defobj; 1599 /* Record the information in the cache to avoid subsequent lookups. */ 1600 if (cache != NULL) { 1601 cache[symnum].sym = def; 1602 cache[symnum].obj = defobj; 1603 } 1604 } else { 1605 if (refobj != &obj_rtld) 1606 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name); 1607 } 1608 return def; 1609} 1610 1611/* 1612 * Return the search path from the ldconfig hints file, reading it if 1613 * necessary. If nostdlib is true, then the default search paths are 1614 * not added to result. 1615 * 1616 * Returns NULL if there are problems with the hints file, 1617 * or if the search path there is empty. 1618 */ 1619static const char * 1620gethints(bool nostdlib) 1621{ 1622 static char *hints, *filtered_path; 1623 struct elfhints_hdr hdr; 1624 struct fill_search_info_args sargs, hargs; 1625 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1626 struct dl_serpath *SLPpath, *hintpath; 1627 char *p; 1628 unsigned int SLPndx, hintndx, fndx, fcount; 1629 int fd; 1630 size_t flen; 1631 bool skip; 1632 1633 /* First call, read the hints file */ 1634 if (hints == NULL) { 1635 /* Keep from trying again in case the hints file is bad. */ 1636 hints = ""; 1637 1638 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1639 return (NULL); 1640 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1641 hdr.magic != ELFHINTS_MAGIC || 1642 hdr.version != 1) { 1643 close(fd); 1644 return (NULL); 1645 } 1646 p = xmalloc(hdr.dirlistlen + 1); 1647 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1648 read(fd, p, hdr.dirlistlen + 1) != 1649 (ssize_t)hdr.dirlistlen + 1) { 1650 free(p); 1651 close(fd); 1652 return (NULL); 1653 } 1654 hints = p; 1655 close(fd); 1656 } 1657 1658 /* 1659 * If caller agreed to receive list which includes the default 1660 * paths, we are done. Otherwise, if we still did not 1661 * calculated filtered result, do it now. 1662 */ 1663 if (!nostdlib) 1664 return (hints[0] != '\0' ? hints : NULL); 1665 if (filtered_path != NULL) 1666 goto filt_ret; 1667 1668 /* 1669 * Obtain the list of all configured search paths, and the 1670 * list of the default paths. 1671 * 1672 * First estimate the size of the results. 1673 */ 1674 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1675 smeta.dls_cnt = 0; 1676 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1677 hmeta.dls_cnt = 0; 1678 1679 sargs.request = RTLD_DI_SERINFOSIZE; 1680 sargs.serinfo = &smeta; 1681 hargs.request = RTLD_DI_SERINFOSIZE; 1682 hargs.serinfo = &hmeta; 1683 1684 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1685 path_enumerate(p, fill_search_info, &hargs); 1686 1687 SLPinfo = xmalloc(smeta.dls_size); 1688 hintinfo = xmalloc(hmeta.dls_size); 1689 1690 /* 1691 * Next fetch both sets of paths. 1692 */ 1693 sargs.request = RTLD_DI_SERINFO; 1694 sargs.serinfo = SLPinfo; 1695 sargs.serpath = &SLPinfo->dls_serpath[0]; 1696 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1697 1698 hargs.request = RTLD_DI_SERINFO; 1699 hargs.serinfo = hintinfo; 1700 hargs.serpath = &hintinfo->dls_serpath[0]; 1701 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1702 1703 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1704 path_enumerate(p, fill_search_info, &hargs); 1705 1706 /* 1707 * Now calculate the difference between two sets, by excluding 1708 * standard paths from the full set. 1709 */ 1710 fndx = 0; 1711 fcount = 0; 1712 filtered_path = xmalloc(hdr.dirlistlen + 1); 1713 hintpath = &hintinfo->dls_serpath[0]; 1714 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1715 skip = false; 1716 SLPpath = &SLPinfo->dls_serpath[0]; 1717 /* 1718 * Check each standard path against current. 1719 */ 1720 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1721 /* matched, skip the path */ 1722 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1723 skip = true; 1724 break; 1725 } 1726 } 1727 if (skip) 1728 continue; 1729 /* 1730 * Not matched against any standard path, add the path 1731 * to result. Separate consequtive paths with ':'. 1732 */ 1733 if (fcount > 0) { 1734 filtered_path[fndx] = ':'; 1735 fndx++; 1736 } 1737 fcount++; 1738 flen = strlen(hintpath->dls_name); 1739 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1740 fndx += flen; 1741 } 1742 filtered_path[fndx] = '\0'; 1743 1744 free(SLPinfo); 1745 free(hintinfo); 1746 1747filt_ret: 1748 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1749} 1750 1751static void 1752init_dag(Obj_Entry *root) 1753{ 1754 const Needed_Entry *needed; 1755 const Objlist_Entry *elm; 1756 DoneList donelist; 1757 1758 if (root->dag_inited) 1759 return; 1760 donelist_init(&donelist); 1761 1762 /* Root object belongs to own DAG. */ 1763 objlist_push_tail(&root->dldags, root); 1764 objlist_push_tail(&root->dagmembers, root); 1765 donelist_check(&donelist, root); 1766 1767 /* 1768 * Add dependencies of root object to DAG in breadth order 1769 * by exploiting the fact that each new object get added 1770 * to the tail of the dagmembers list. 1771 */ 1772 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1773 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1774 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1775 continue; 1776 objlist_push_tail(&needed->obj->dldags, root); 1777 objlist_push_tail(&root->dagmembers, needed->obj); 1778 } 1779 } 1780 root->dag_inited = true; 1781} 1782 1783static void 1784process_z(Obj_Entry *root) 1785{ 1786 const Objlist_Entry *elm; 1787 Obj_Entry *obj; 1788 1789 /* 1790 * Walk over object DAG and process every dependent object 1791 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 1792 * to grow their own DAG. 1793 * 1794 * For DF_1_GLOBAL, DAG is required for symbol lookups in 1795 * symlook_global() to work. 1796 * 1797 * For DF_1_NODELETE, the DAG should have its reference upped. 1798 */ 1799 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1800 obj = elm->obj; 1801 if (obj == NULL) 1802 continue; 1803 if (obj->z_nodelete && !obj->ref_nodel) { 1804 dbg("obj %s -z nodelete", obj->path); 1805 init_dag(obj); 1806 ref_dag(obj); 1807 obj->ref_nodel = true; 1808 } 1809 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 1810 dbg("obj %s -z global", obj->path); 1811 objlist_push_tail(&list_global, obj); 1812 init_dag(obj); 1813 } 1814 } 1815} 1816/* 1817 * Initialize the dynamic linker. The argument is the address at which 1818 * the dynamic linker has been mapped into memory. The primary task of 1819 * this function is to relocate the dynamic linker. 1820 */ 1821static void 1822init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 1823{ 1824 Obj_Entry objtmp; /* Temporary rtld object */ 1825 const Elf_Dyn *dyn_rpath; 1826 const Elf_Dyn *dyn_soname; 1827 const Elf_Dyn *dyn_runpath; 1828 1829#ifdef RTLD_INIT_PAGESIZES_EARLY 1830 /* The page size is required by the dynamic memory allocator. */ 1831 init_pagesizes(aux_info); 1832#endif 1833 1834 /* 1835 * Conjure up an Obj_Entry structure for the dynamic linker. 1836 * 1837 * The "path" member can't be initialized yet because string constants 1838 * cannot yet be accessed. Below we will set it correctly. 1839 */ 1840 memset(&objtmp, 0, sizeof(objtmp)); 1841 objtmp.path = NULL; 1842 objtmp.rtld = true; 1843 objtmp.mapbase = mapbase; 1844#ifdef PIC 1845 objtmp.relocbase = mapbase; 1846#endif 1847 if (RTLD_IS_DYNAMIC()) { 1848 objtmp.dynamic = rtld_dynamic(&objtmp); 1849 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 1850 assert(objtmp.needed == NULL); 1851#if !defined(__mips__) 1852 /* MIPS has a bogus DT_TEXTREL. */ 1853 assert(!objtmp.textrel); 1854#endif 1855 1856 /* 1857 * Temporarily put the dynamic linker entry into the object list, so 1858 * that symbols can be found. 1859 */ 1860 1861 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 1862 } 1863 1864 /* Initialize the object list. */ 1865 obj_tail = &obj_list; 1866 1867 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1868 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1869 1870#ifndef RTLD_INIT_PAGESIZES_EARLY 1871 /* The page size is required by the dynamic memory allocator. */ 1872 init_pagesizes(aux_info); 1873#endif 1874 1875 if (aux_info[AT_OSRELDATE] != NULL) 1876 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 1877 1878 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 1879 1880 /* Replace the path with a dynamically allocated copy. */ 1881 obj_rtld.path = xstrdup(PATH_RTLD); 1882 1883 r_debug.r_brk = r_debug_state; 1884 r_debug.r_state = RT_CONSISTENT; 1885} 1886 1887/* 1888 * Retrieve the array of supported page sizes. The kernel provides the page 1889 * sizes in increasing order. 1890 */ 1891static void 1892init_pagesizes(Elf_Auxinfo **aux_info) 1893{ 1894 static size_t psa[MAXPAGESIZES]; 1895 int mib[2]; 1896 size_t len, size; 1897 1898 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 1899 NULL) { 1900 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 1901 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 1902 } else { 1903 len = 2; 1904 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 1905 size = sizeof(psa); 1906 else { 1907 /* As a fallback, retrieve the base page size. */ 1908 size = sizeof(psa[0]); 1909 if (aux_info[AT_PAGESZ] != NULL) { 1910 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 1911 goto psa_filled; 1912 } else { 1913 mib[0] = CTL_HW; 1914 mib[1] = HW_PAGESIZE; 1915 len = 2; 1916 } 1917 } 1918 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 1919 _rtld_error("sysctl for hw.pagesize(s) failed"); 1920 rtld_die(); 1921 } 1922psa_filled: 1923 pagesizes = psa; 1924 } 1925 npagesizes = size / sizeof(pagesizes[0]); 1926 /* Discard any invalid entries at the end of the array. */ 1927 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 1928 npagesizes--; 1929} 1930 1931/* 1932 * Add the init functions from a needed object list (and its recursive 1933 * needed objects) to "list". This is not used directly; it is a helper 1934 * function for initlist_add_objects(). The write lock must be held 1935 * when this function is called. 1936 */ 1937static void 1938initlist_add_neededs(Needed_Entry *needed, Objlist *list) 1939{ 1940 /* Recursively process the successor needed objects. */ 1941 if (needed->next != NULL) 1942 initlist_add_neededs(needed->next, list); 1943 1944 /* Process the current needed object. */ 1945 if (needed->obj != NULL) 1946 initlist_add_objects(needed->obj, &needed->obj->next, list); 1947} 1948 1949/* 1950 * Scan all of the DAGs rooted in the range of objects from "obj" to 1951 * "tail" and add their init functions to "list". This recurses over 1952 * the DAGs and ensure the proper init ordering such that each object's 1953 * needed libraries are initialized before the object itself. At the 1954 * same time, this function adds the objects to the global finalization 1955 * list "list_fini" in the opposite order. The write lock must be 1956 * held when this function is called. 1957 */ 1958static void 1959initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list) 1960{ 1961 1962 if (obj->init_scanned || obj->init_done) 1963 return; 1964 obj->init_scanned = true; 1965 1966 /* Recursively process the successor objects. */ 1967 if (&obj->next != tail) 1968 initlist_add_objects(obj->next, tail, list); 1969 1970 /* Recursively process the needed objects. */ 1971 if (obj->needed != NULL) 1972 initlist_add_neededs(obj->needed, list); 1973 if (obj->needed_filtees != NULL) 1974 initlist_add_neededs(obj->needed_filtees, list); 1975 if (obj->needed_aux_filtees != NULL) 1976 initlist_add_neededs(obj->needed_aux_filtees, list); 1977 1978 /* Add the object to the init list. */ 1979 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL || 1980 obj->init_array != (Elf_Addr)NULL) 1981 objlist_push_tail(list, obj); 1982 1983 /* Add the object to the global fini list in the reverse order. */ 1984 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 1985 && !obj->on_fini_list) { 1986 objlist_push_head(&list_fini, obj); 1987 obj->on_fini_list = true; 1988 } 1989} 1990 1991#ifndef FPTR_TARGET 1992#define FPTR_TARGET(f) ((Elf_Addr) (f)) 1993#endif 1994 1995static void 1996free_needed_filtees(Needed_Entry *n) 1997{ 1998 Needed_Entry *needed, *needed1; 1999 2000 for (needed = n; needed != NULL; needed = needed->next) { 2001 if (needed->obj != NULL) { 2002 dlclose(needed->obj); 2003 needed->obj = NULL; 2004 } 2005 } 2006 for (needed = n; needed != NULL; needed = needed1) { 2007 needed1 = needed->next; 2008 free(needed); 2009 } 2010} 2011 2012static void 2013unload_filtees(Obj_Entry *obj) 2014{ 2015 2016 free_needed_filtees(obj->needed_filtees); 2017 obj->needed_filtees = NULL; 2018 free_needed_filtees(obj->needed_aux_filtees); 2019 obj->needed_aux_filtees = NULL; 2020 obj->filtees_loaded = false; 2021} 2022 2023static void 2024load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2025 RtldLockState *lockstate) 2026{ 2027 2028 for (; needed != NULL; needed = needed->next) { 2029 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2030 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2031 RTLD_LOCAL, lockstate); 2032 } 2033} 2034 2035static void 2036load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2037{ 2038 2039 lock_restart_for_upgrade(lockstate); 2040 if (!obj->filtees_loaded) { 2041 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2042 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2043 obj->filtees_loaded = true; 2044 } 2045} 2046 2047static int 2048process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2049{ 2050 Obj_Entry *obj1; 2051 2052 for (; needed != NULL; needed = needed->next) { 2053 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2054 flags & ~RTLD_LO_NOLOAD); 2055 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2056 return (-1); 2057 } 2058 return (0); 2059} 2060 2061/* 2062 * Given a shared object, traverse its list of needed objects, and load 2063 * each of them. Returns 0 on success. Generates an error message and 2064 * returns -1 on failure. 2065 */ 2066static int 2067load_needed_objects(Obj_Entry *first, int flags) 2068{ 2069 Obj_Entry *obj; 2070 2071 for (obj = first; obj != NULL; obj = obj->next) { 2072 if (process_needed(obj, obj->needed, flags) == -1) 2073 return (-1); 2074 } 2075 return (0); 2076} 2077 2078static int 2079load_preload_objects(void) 2080{ 2081 char *p = ld_preload; 2082 Obj_Entry *obj; 2083 static const char delim[] = " \t:;"; 2084 2085 if (p == NULL) 2086 return 0; 2087 2088 p += strspn(p, delim); 2089 while (*p != '\0') { 2090 size_t len = strcspn(p, delim); 2091 char savech; 2092 2093 savech = p[len]; 2094 p[len] = '\0'; 2095 obj = load_object(p, -1, NULL, 0); 2096 if (obj == NULL) 2097 return -1; /* XXX - cleanup */ 2098 obj->z_interpose = true; 2099 p[len] = savech; 2100 p += len; 2101 p += strspn(p, delim); 2102 } 2103 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2104 return 0; 2105} 2106 2107static const char * 2108printable_path(const char *path) 2109{ 2110 2111 return (path == NULL ? "<unknown>" : path); 2112} 2113 2114/* 2115 * Load a shared object into memory, if it is not already loaded. The 2116 * object may be specified by name or by user-supplied file descriptor 2117 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2118 * duplicate is. 2119 * 2120 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2121 * on failure. 2122 */ 2123static Obj_Entry * 2124load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2125{ 2126 Obj_Entry *obj; 2127 int fd; 2128 struct stat sb; 2129 char *path; 2130 2131 if (name != NULL) { 2132 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 2133 if (object_match_name(obj, name)) 2134 return (obj); 2135 } 2136 2137 path = find_library(name, refobj); 2138 if (path == NULL) 2139 return (NULL); 2140 } else 2141 path = NULL; 2142 2143 /* 2144 * If we didn't find a match by pathname, or the name is not 2145 * supplied, open the file and check again by device and inode. 2146 * This avoids false mismatches caused by multiple links or ".." 2147 * in pathnames. 2148 * 2149 * To avoid a race, we open the file and use fstat() rather than 2150 * using stat(). 2151 */ 2152 fd = -1; 2153 if (fd_u == -1) { 2154 if ((fd = open(path, O_RDONLY | O_CLOEXEC)) == -1) { 2155 _rtld_error("Cannot open \"%s\"", path); 2156 free(path); 2157 return (NULL); 2158 } 2159 } else { 2160 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2161 if (fd == -1) { 2162 _rtld_error("Cannot dup fd"); 2163 free(path); 2164 return (NULL); 2165 } 2166 } 2167 if (fstat(fd, &sb) == -1) { 2168 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2169 close(fd); 2170 free(path); 2171 return NULL; 2172 } 2173 for (obj = obj_list->next; obj != NULL; obj = obj->next) 2174 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2175 break; 2176 if (obj != NULL && name != NULL) { 2177 object_add_name(obj, name); 2178 free(path); 2179 close(fd); 2180 return obj; 2181 } 2182 if (flags & RTLD_LO_NOLOAD) { 2183 free(path); 2184 close(fd); 2185 return (NULL); 2186 } 2187 2188 /* First use of this object, so we must map it in */ 2189 obj = do_load_object(fd, name, path, &sb, flags); 2190 if (obj == NULL) 2191 free(path); 2192 close(fd); 2193 2194 return obj; 2195} 2196 2197static Obj_Entry * 2198do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2199 int flags) 2200{ 2201 Obj_Entry *obj; 2202 struct statfs fs; 2203 2204 /* 2205 * but first, make sure that environment variables haven't been 2206 * used to circumvent the noexec flag on a filesystem. 2207 */ 2208 if (dangerous_ld_env) { 2209 if (fstatfs(fd, &fs) != 0) { 2210 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2211 return NULL; 2212 } 2213 if (fs.f_flags & MNT_NOEXEC) { 2214 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 2215 return NULL; 2216 } 2217 } 2218 dbg("loading \"%s\"", printable_path(path)); 2219 obj = map_object(fd, printable_path(path), sbp); 2220 if (obj == NULL) 2221 return NULL; 2222 2223 /* 2224 * If DT_SONAME is present in the object, digest_dynamic2 already 2225 * added it to the object names. 2226 */ 2227 if (name != NULL) 2228 object_add_name(obj, name); 2229 obj->path = path; 2230 digest_dynamic(obj, 0); 2231 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2232 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2233 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2234 RTLD_LO_DLOPEN) { 2235 dbg("refusing to load non-loadable \"%s\"", obj->path); 2236 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2237 munmap(obj->mapbase, obj->mapsize); 2238 obj_free(obj); 2239 return (NULL); 2240 } 2241 2242 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2243 *obj_tail = obj; 2244 obj_tail = &obj->next; 2245 obj_count++; 2246 obj_loads++; 2247 linkmap_add(obj); /* for GDB & dlinfo() */ 2248 max_stack_flags |= obj->stack_flags; 2249 2250 dbg(" %p .. %p: %s", obj->mapbase, 2251 obj->mapbase + obj->mapsize - 1, obj->path); 2252 if (obj->textrel) 2253 dbg(" WARNING: %s has impure text", obj->path); 2254 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2255 obj->path); 2256 2257 return obj; 2258} 2259 2260static Obj_Entry * 2261obj_from_addr(const void *addr) 2262{ 2263 Obj_Entry *obj; 2264 2265 for (obj = obj_list; obj != NULL; obj = obj->next) { 2266 if (addr < (void *) obj->mapbase) 2267 continue; 2268 if (addr < (void *) (obj->mapbase + obj->mapsize)) 2269 return obj; 2270 } 2271 return NULL; 2272} 2273 2274static void 2275preinit_main(void) 2276{ 2277 Elf_Addr *preinit_addr; 2278 int index; 2279 2280 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2281 if (preinit_addr == NULL) 2282 return; 2283 2284 for (index = 0; index < obj_main->preinit_array_num; index++) { 2285 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2286 dbg("calling preinit function for %s at %p", obj_main->path, 2287 (void *)preinit_addr[index]); 2288 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2289 0, 0, obj_main->path); 2290 call_init_pointer(obj_main, preinit_addr[index]); 2291 } 2292 } 2293} 2294 2295/* 2296 * Call the finalization functions for each of the objects in "list" 2297 * belonging to the DAG of "root" and referenced once. If NULL "root" 2298 * is specified, every finalization function will be called regardless 2299 * of the reference count and the list elements won't be freed. All of 2300 * the objects are expected to have non-NULL fini functions. 2301 */ 2302static void 2303objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2304{ 2305 Objlist_Entry *elm; 2306 char *saved_msg; 2307 Elf_Addr *fini_addr; 2308 int index; 2309 2310 assert(root == NULL || root->refcount == 1); 2311 2312 /* 2313 * Preserve the current error message since a fini function might 2314 * call into the dynamic linker and overwrite it. 2315 */ 2316 saved_msg = errmsg_save(); 2317 do { 2318 STAILQ_FOREACH(elm, list, link) { 2319 if (root != NULL && (elm->obj->refcount != 1 || 2320 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2321 continue; 2322 /* Remove object from fini list to prevent recursive invocation. */ 2323 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2324 /* 2325 * XXX: If a dlopen() call references an object while the 2326 * fini function is in progress, we might end up trying to 2327 * unload the referenced object in dlclose() or the object 2328 * won't be unloaded although its fini function has been 2329 * called. 2330 */ 2331 lock_release(rtld_bind_lock, lockstate); 2332 2333 /* 2334 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2335 * When this happens, DT_FINI_ARRAY is processed first. 2336 */ 2337 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2338 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2339 for (index = elm->obj->fini_array_num - 1; index >= 0; 2340 index--) { 2341 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2342 dbg("calling fini function for %s at %p", 2343 elm->obj->path, (void *)fini_addr[index]); 2344 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2345 (void *)fini_addr[index], 0, 0, elm->obj->path); 2346 call_initfini_pointer(elm->obj, fini_addr[index]); 2347 } 2348 } 2349 } 2350 if (elm->obj->fini != (Elf_Addr)NULL) { 2351 dbg("calling fini function for %s at %p", elm->obj->path, 2352 (void *)elm->obj->fini); 2353 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2354 0, 0, elm->obj->path); 2355 call_initfini_pointer(elm->obj, elm->obj->fini); 2356 } 2357 wlock_acquire(rtld_bind_lock, lockstate); 2358 /* No need to free anything if process is going down. */ 2359 if (root != NULL) 2360 free(elm); 2361 /* 2362 * We must restart the list traversal after every fini call 2363 * because a dlclose() call from the fini function or from 2364 * another thread might have modified the reference counts. 2365 */ 2366 break; 2367 } 2368 } while (elm != NULL); 2369 errmsg_restore(saved_msg); 2370} 2371 2372/* 2373 * Call the initialization functions for each of the objects in 2374 * "list". All of the objects are expected to have non-NULL init 2375 * functions. 2376 */ 2377static void 2378objlist_call_init(Objlist *list, RtldLockState *lockstate) 2379{ 2380 Objlist_Entry *elm; 2381 Obj_Entry *obj; 2382 char *saved_msg; 2383 Elf_Addr *init_addr; 2384 int index; 2385 2386 /* 2387 * Clean init_scanned flag so that objects can be rechecked and 2388 * possibly initialized earlier if any of vectors called below 2389 * cause the change by using dlopen. 2390 */ 2391 for (obj = obj_list; obj != NULL; obj = obj->next) 2392 obj->init_scanned = false; 2393 2394 /* 2395 * Preserve the current error message since an init function might 2396 * call into the dynamic linker and overwrite it. 2397 */ 2398 saved_msg = errmsg_save(); 2399 STAILQ_FOREACH(elm, list, link) { 2400 if (elm->obj->init_done) /* Initialized early. */ 2401 continue; 2402 /* 2403 * Race: other thread might try to use this object before current 2404 * one completes the initilization. Not much can be done here 2405 * without better locking. 2406 */ 2407 elm->obj->init_done = true; 2408 lock_release(rtld_bind_lock, lockstate); 2409 2410 /* 2411 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2412 * When this happens, DT_INIT is processed first. 2413 */ 2414 if (elm->obj->init != (Elf_Addr)NULL) { 2415 dbg("calling init function for %s at %p", elm->obj->path, 2416 (void *)elm->obj->init); 2417 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2418 0, 0, elm->obj->path); 2419 call_initfini_pointer(elm->obj, elm->obj->init); 2420 } 2421 init_addr = (Elf_Addr *)elm->obj->init_array; 2422 if (init_addr != NULL) { 2423 for (index = 0; index < elm->obj->init_array_num; index++) { 2424 if (init_addr[index] != 0 && init_addr[index] != 1) { 2425 dbg("calling init function for %s at %p", elm->obj->path, 2426 (void *)init_addr[index]); 2427 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2428 (void *)init_addr[index], 0, 0, elm->obj->path); 2429 call_init_pointer(elm->obj, init_addr[index]); 2430 } 2431 } 2432 } 2433 wlock_acquire(rtld_bind_lock, lockstate); 2434 } 2435 errmsg_restore(saved_msg); 2436} 2437 2438static void 2439objlist_clear(Objlist *list) 2440{ 2441 Objlist_Entry *elm; 2442 2443 while (!STAILQ_EMPTY(list)) { 2444 elm = STAILQ_FIRST(list); 2445 STAILQ_REMOVE_HEAD(list, link); 2446 free(elm); 2447 } 2448} 2449 2450static Objlist_Entry * 2451objlist_find(Objlist *list, const Obj_Entry *obj) 2452{ 2453 Objlist_Entry *elm; 2454 2455 STAILQ_FOREACH(elm, list, link) 2456 if (elm->obj == obj) 2457 return elm; 2458 return NULL; 2459} 2460 2461static void 2462objlist_init(Objlist *list) 2463{ 2464 STAILQ_INIT(list); 2465} 2466 2467static void 2468objlist_push_head(Objlist *list, Obj_Entry *obj) 2469{ 2470 Objlist_Entry *elm; 2471 2472 elm = NEW(Objlist_Entry); 2473 elm->obj = obj; 2474 STAILQ_INSERT_HEAD(list, elm, link); 2475} 2476 2477static void 2478objlist_push_tail(Objlist *list, Obj_Entry *obj) 2479{ 2480 Objlist_Entry *elm; 2481 2482 elm = NEW(Objlist_Entry); 2483 elm->obj = obj; 2484 STAILQ_INSERT_TAIL(list, elm, link); 2485} 2486 2487static void 2488objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2489{ 2490 Objlist_Entry *elm, *listelm; 2491 2492 STAILQ_FOREACH(listelm, list, link) { 2493 if (listelm->obj == listobj) 2494 break; 2495 } 2496 elm = NEW(Objlist_Entry); 2497 elm->obj = obj; 2498 if (listelm != NULL) 2499 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2500 else 2501 STAILQ_INSERT_TAIL(list, elm, link); 2502} 2503 2504static void 2505objlist_remove(Objlist *list, Obj_Entry *obj) 2506{ 2507 Objlist_Entry *elm; 2508 2509 if ((elm = objlist_find(list, obj)) != NULL) { 2510 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2511 free(elm); 2512 } 2513} 2514 2515/* 2516 * Relocate dag rooted in the specified object. 2517 * Returns 0 on success, or -1 on failure. 2518 */ 2519 2520static int 2521relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2522 int flags, RtldLockState *lockstate) 2523{ 2524 Objlist_Entry *elm; 2525 int error; 2526 2527 error = 0; 2528 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2529 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2530 lockstate); 2531 if (error == -1) 2532 break; 2533 } 2534 return (error); 2535} 2536 2537/* 2538 * Relocate single object. 2539 * Returns 0 on success, or -1 on failure. 2540 */ 2541static int 2542relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2543 int flags, RtldLockState *lockstate) 2544{ 2545 2546 if (obj->relocated) 2547 return (0); 2548 obj->relocated = true; 2549 if (obj != rtldobj) 2550 dbg("relocating \"%s\"", obj->path); 2551 2552 if (obj->symtab == NULL || obj->strtab == NULL || 2553 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2554 _rtld_error("%s: Shared object has no run-time symbol table", 2555 obj->path); 2556 return (-1); 2557 } 2558 2559 if (obj->textrel) { 2560 /* There are relocations to the write-protected text segment. */ 2561 if (mprotect(obj->mapbase, obj->textsize, 2562 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) { 2563 _rtld_error("%s: Cannot write-enable text segment: %s", 2564 obj->path, rtld_strerror(errno)); 2565 return (-1); 2566 } 2567 } 2568 2569 /* Process the non-PLT non-IFUNC relocations. */ 2570 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2571 return (-1); 2572 2573 if (obj->textrel) { /* Re-protected the text segment. */ 2574 if (mprotect(obj->mapbase, obj->textsize, 2575 PROT_READ|PROT_EXEC) == -1) { 2576 _rtld_error("%s: Cannot write-protect text segment: %s", 2577 obj->path, rtld_strerror(errno)); 2578 return (-1); 2579 } 2580 } 2581 2582 /* Set the special PLT or GOT entries. */ 2583 init_pltgot(obj); 2584 2585 /* Process the PLT relocations. */ 2586 if (reloc_plt(obj) == -1) 2587 return (-1); 2588 /* Relocate the jump slots if we are doing immediate binding. */ 2589 if (obj->bind_now || bind_now) 2590 if (reloc_jmpslots(obj, flags, lockstate) == -1) 2591 return (-1); 2592 2593 /* 2594 * Process the non-PLT IFUNC relocations. The relocations are 2595 * processed in two phases, because IFUNC resolvers may 2596 * reference other symbols, which must be readily processed 2597 * before resolvers are called. 2598 */ 2599 if (obj->non_plt_gnu_ifunc && 2600 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate)) 2601 return (-1); 2602 2603 if (obj->relro_size > 0) { 2604 if (mprotect(obj->relro_page, obj->relro_size, 2605 PROT_READ) == -1) { 2606 _rtld_error("%s: Cannot enforce relro protection: %s", 2607 obj->path, rtld_strerror(errno)); 2608 return (-1); 2609 } 2610 } 2611 2612 /* 2613 * Set up the magic number and version in the Obj_Entry. These 2614 * were checked in the crt1.o from the original ElfKit, so we 2615 * set them for backward compatibility. 2616 */ 2617 obj->magic = RTLD_MAGIC; 2618 obj->version = RTLD_VERSION; 2619 2620 return (0); 2621} 2622 2623/* 2624 * Relocate newly-loaded shared objects. The argument is a pointer to 2625 * the Obj_Entry for the first such object. All objects from the first 2626 * to the end of the list of objects are relocated. Returns 0 on success, 2627 * or -1 on failure. 2628 */ 2629static int 2630relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2631 int flags, RtldLockState *lockstate) 2632{ 2633 Obj_Entry *obj; 2634 int error; 2635 2636 for (error = 0, obj = first; obj != NULL; obj = obj->next) { 2637 error = relocate_object(obj, bind_now, rtldobj, flags, 2638 lockstate); 2639 if (error == -1) 2640 break; 2641 } 2642 return (error); 2643} 2644 2645/* 2646 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2647 * referencing STT_GNU_IFUNC symbols is postponed till the other 2648 * relocations are done. The indirect functions specified as 2649 * ifunc are allowed to call other symbols, so we need to have 2650 * objects relocated before asking for resolution from indirects. 2651 * 2652 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2653 * instead of the usual lazy handling of PLT slots. It is 2654 * consistent with how GNU does it. 2655 */ 2656static int 2657resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2658 RtldLockState *lockstate) 2659{ 2660 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2661 return (-1); 2662 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2663 reloc_gnu_ifunc(obj, flags, lockstate) == -1) 2664 return (-1); 2665 return (0); 2666} 2667 2668static int 2669resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags, 2670 RtldLockState *lockstate) 2671{ 2672 Obj_Entry *obj; 2673 2674 for (obj = first; obj != NULL; obj = obj->next) { 2675 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1) 2676 return (-1); 2677 } 2678 return (0); 2679} 2680 2681static int 2682initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2683 RtldLockState *lockstate) 2684{ 2685 Objlist_Entry *elm; 2686 2687 STAILQ_FOREACH(elm, list, link) { 2688 if (resolve_object_ifunc(elm->obj, bind_now, flags, 2689 lockstate) == -1) 2690 return (-1); 2691 } 2692 return (0); 2693} 2694 2695/* 2696 * Cleanup procedure. It will be called (by the atexit mechanism) just 2697 * before the process exits. 2698 */ 2699static void 2700rtld_exit(void) 2701{ 2702 RtldLockState lockstate; 2703 2704 wlock_acquire(rtld_bind_lock, &lockstate); 2705 dbg("rtld_exit()"); 2706 objlist_call_fini(&list_fini, NULL, &lockstate); 2707 /* No need to remove the items from the list, since we are exiting. */ 2708 if (!libmap_disable) 2709 lm_fini(); 2710 lock_release(rtld_bind_lock, &lockstate); 2711} 2712 2713/* 2714 * Iterate over a search path, translate each element, and invoke the 2715 * callback on the result. 2716 */ 2717static void * 2718path_enumerate(const char *path, path_enum_proc callback, void *arg) 2719{ 2720 const char *trans; 2721 if (path == NULL) 2722 return (NULL); 2723 2724 path += strspn(path, ":;"); 2725 while (*path != '\0') { 2726 size_t len; 2727 char *res; 2728 2729 len = strcspn(path, ":;"); 2730 trans = lm_findn(NULL, path, len); 2731 if (trans) 2732 res = callback(trans, strlen(trans), arg); 2733 else 2734 res = callback(path, len, arg); 2735 2736 if (res != NULL) 2737 return (res); 2738 2739 path += len; 2740 path += strspn(path, ":;"); 2741 } 2742 2743 return (NULL); 2744} 2745 2746struct try_library_args { 2747 const char *name; 2748 size_t namelen; 2749 char *buffer; 2750 size_t buflen; 2751}; 2752 2753static void * 2754try_library_path(const char *dir, size_t dirlen, void *param) 2755{ 2756 struct try_library_args *arg; 2757 2758 arg = param; 2759 if (*dir == '/' || trust) { 2760 char *pathname; 2761 2762 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 2763 return (NULL); 2764 2765 pathname = arg->buffer; 2766 strncpy(pathname, dir, dirlen); 2767 pathname[dirlen] = '/'; 2768 strcpy(pathname + dirlen + 1, arg->name); 2769 2770 dbg(" Trying \"%s\"", pathname); 2771 if (access(pathname, F_OK) == 0) { /* We found it */ 2772 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 2773 strcpy(pathname, arg->buffer); 2774 return (pathname); 2775 } 2776 } 2777 return (NULL); 2778} 2779 2780static char * 2781search_library_path(const char *name, const char *path) 2782{ 2783 char *p; 2784 struct try_library_args arg; 2785 2786 if (path == NULL) 2787 return NULL; 2788 2789 arg.name = name; 2790 arg.namelen = strlen(name); 2791 arg.buffer = xmalloc(PATH_MAX); 2792 arg.buflen = PATH_MAX; 2793 2794 p = path_enumerate(path, try_library_path, &arg); 2795 2796 free(arg.buffer); 2797 2798 return (p); 2799} 2800 2801int 2802dlclose(void *handle) 2803{ 2804 Obj_Entry *root; 2805 RtldLockState lockstate; 2806 2807 wlock_acquire(rtld_bind_lock, &lockstate); 2808 root = dlcheck(handle); 2809 if (root == NULL) { 2810 lock_release(rtld_bind_lock, &lockstate); 2811 return -1; 2812 } 2813 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 2814 root->path); 2815 2816 /* Unreference the object and its dependencies. */ 2817 root->dl_refcount--; 2818 2819 if (root->refcount == 1) { 2820 /* 2821 * The object will be no longer referenced, so we must unload it. 2822 * First, call the fini functions. 2823 */ 2824 objlist_call_fini(&list_fini, root, &lockstate); 2825 2826 unref_dag(root); 2827 2828 /* Finish cleaning up the newly-unreferenced objects. */ 2829 GDB_STATE(RT_DELETE,&root->linkmap); 2830 unload_object(root); 2831 GDB_STATE(RT_CONSISTENT,NULL); 2832 } else 2833 unref_dag(root); 2834 2835 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 2836 lock_release(rtld_bind_lock, &lockstate); 2837 return 0; 2838} 2839 2840char * 2841dlerror(void) 2842{ 2843 char *msg = error_message; 2844 error_message = NULL; 2845 return msg; 2846} 2847 2848/* 2849 * This function is deprecated and has no effect. 2850 */ 2851void 2852dllockinit(void *context, 2853 void *(*lock_create)(void *context), 2854 void (*rlock_acquire)(void *lock), 2855 void (*wlock_acquire)(void *lock), 2856 void (*lock_release)(void *lock), 2857 void (*lock_destroy)(void *lock), 2858 void (*context_destroy)(void *context)) 2859{ 2860 static void *cur_context; 2861 static void (*cur_context_destroy)(void *); 2862 2863 /* Just destroy the context from the previous call, if necessary. */ 2864 if (cur_context_destroy != NULL) 2865 cur_context_destroy(cur_context); 2866 cur_context = context; 2867 cur_context_destroy = context_destroy; 2868} 2869 2870void * 2871dlopen(const char *name, int mode) 2872{ 2873 2874 return (rtld_dlopen(name, -1, mode)); 2875} 2876 2877void * 2878fdlopen(int fd, int mode) 2879{ 2880 2881 return (rtld_dlopen(NULL, fd, mode)); 2882} 2883 2884static void * 2885rtld_dlopen(const char *name, int fd, int mode) 2886{ 2887 RtldLockState lockstate; 2888 int lo_flags; 2889 2890 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 2891 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 2892 if (ld_tracing != NULL) { 2893 rlock_acquire(rtld_bind_lock, &lockstate); 2894 if (sigsetjmp(lockstate.env, 0) != 0) 2895 lock_upgrade(rtld_bind_lock, &lockstate); 2896 environ = (char **)*get_program_var_addr("environ", &lockstate); 2897 lock_release(rtld_bind_lock, &lockstate); 2898 } 2899 lo_flags = RTLD_LO_DLOPEN; 2900 if (mode & RTLD_NODELETE) 2901 lo_flags |= RTLD_LO_NODELETE; 2902 if (mode & RTLD_NOLOAD) 2903 lo_flags |= RTLD_LO_NOLOAD; 2904 if (ld_tracing != NULL) 2905 lo_flags |= RTLD_LO_TRACE; 2906 2907 return (dlopen_object(name, fd, obj_main, lo_flags, 2908 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 2909} 2910 2911static void 2912dlopen_cleanup(Obj_Entry *obj) 2913{ 2914 2915 obj->dl_refcount--; 2916 unref_dag(obj); 2917 if (obj->refcount == 0) 2918 unload_object(obj); 2919} 2920 2921static Obj_Entry * 2922dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 2923 int mode, RtldLockState *lockstate) 2924{ 2925 Obj_Entry **old_obj_tail; 2926 Obj_Entry *obj; 2927 Objlist initlist; 2928 RtldLockState mlockstate; 2929 int result; 2930 2931 objlist_init(&initlist); 2932 2933 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 2934 wlock_acquire(rtld_bind_lock, &mlockstate); 2935 lockstate = &mlockstate; 2936 } 2937 GDB_STATE(RT_ADD,NULL); 2938 2939 old_obj_tail = obj_tail; 2940 obj = NULL; 2941 if (name == NULL && fd == -1) { 2942 obj = obj_main; 2943 obj->refcount++; 2944 } else { 2945 obj = load_object(name, fd, refobj, lo_flags); 2946 } 2947 2948 if (obj) { 2949 obj->dl_refcount++; 2950 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 2951 objlist_push_tail(&list_global, obj); 2952 if (*old_obj_tail != NULL) { /* We loaded something new. */ 2953 assert(*old_obj_tail == obj); 2954 result = load_needed_objects(obj, 2955 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 2956 init_dag(obj); 2957 ref_dag(obj); 2958 if (result != -1) 2959 result = rtld_verify_versions(&obj->dagmembers); 2960 if (result != -1 && ld_tracing) 2961 goto trace; 2962 if (result == -1 || relocate_object_dag(obj, 2963 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 2964 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 2965 lockstate) == -1) { 2966 dlopen_cleanup(obj); 2967 obj = NULL; 2968 } else if (lo_flags & RTLD_LO_EARLY) { 2969 /* 2970 * Do not call the init functions for early loaded 2971 * filtees. The image is still not initialized enough 2972 * for them to work. 2973 * 2974 * Our object is found by the global object list and 2975 * will be ordered among all init calls done right 2976 * before transferring control to main. 2977 */ 2978 } else { 2979 /* Make list of init functions to call. */ 2980 initlist_add_objects(obj, &obj->next, &initlist); 2981 } 2982 /* 2983 * Process all no_delete or global objects here, given 2984 * them own DAGs to prevent their dependencies from being 2985 * unloaded. This has to be done after we have loaded all 2986 * of the dependencies, so that we do not miss any. 2987 */ 2988 if (obj != NULL) 2989 process_z(obj); 2990 } else { 2991 /* 2992 * Bump the reference counts for objects on this DAG. If 2993 * this is the first dlopen() call for the object that was 2994 * already loaded as a dependency, initialize the dag 2995 * starting at it. 2996 */ 2997 init_dag(obj); 2998 ref_dag(obj); 2999 3000 if ((lo_flags & RTLD_LO_TRACE) != 0) 3001 goto trace; 3002 } 3003 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3004 obj->z_nodelete) && !obj->ref_nodel) { 3005 dbg("obj %s nodelete", obj->path); 3006 ref_dag(obj); 3007 obj->z_nodelete = obj->ref_nodel = true; 3008 } 3009 } 3010 3011 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3012 name); 3013 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3014 3015 if (!(lo_flags & RTLD_LO_EARLY)) { 3016 map_stacks_exec(lockstate); 3017 } 3018 3019 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3020 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3021 lockstate) == -1) { 3022 objlist_clear(&initlist); 3023 dlopen_cleanup(obj); 3024 if (lockstate == &mlockstate) 3025 lock_release(rtld_bind_lock, lockstate); 3026 return (NULL); 3027 } 3028 3029 if (!(lo_flags & RTLD_LO_EARLY)) { 3030 /* Call the init functions. */ 3031 objlist_call_init(&initlist, lockstate); 3032 } 3033 objlist_clear(&initlist); 3034 if (lockstate == &mlockstate) 3035 lock_release(rtld_bind_lock, lockstate); 3036 return obj; 3037trace: 3038 trace_loaded_objects(obj); 3039 if (lockstate == &mlockstate) 3040 lock_release(rtld_bind_lock, lockstate); 3041 exit(0); 3042} 3043 3044static void * 3045do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3046 int flags) 3047{ 3048 DoneList donelist; 3049 const Obj_Entry *obj, *defobj; 3050 const Elf_Sym *def; 3051 SymLook req; 3052 RtldLockState lockstate; 3053#ifndef __ia64__ 3054 tls_index ti; 3055#endif 3056 void *sym; 3057 int res; 3058 3059 def = NULL; 3060 defobj = NULL; 3061 symlook_init(&req, name); 3062 req.ventry = ve; 3063 req.flags = flags | SYMLOOK_IN_PLT; 3064 req.lockstate = &lockstate; 3065 3066 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3067 rlock_acquire(rtld_bind_lock, &lockstate); 3068 if (sigsetjmp(lockstate.env, 0) != 0) 3069 lock_upgrade(rtld_bind_lock, &lockstate); 3070 if (handle == NULL || handle == RTLD_NEXT || 3071 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3072 3073 if ((obj = obj_from_addr(retaddr)) == NULL) { 3074 _rtld_error("Cannot determine caller's shared object"); 3075 lock_release(rtld_bind_lock, &lockstate); 3076 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3077 return NULL; 3078 } 3079 if (handle == NULL) { /* Just the caller's shared object. */ 3080 res = symlook_obj(&req, obj); 3081 if (res == 0) { 3082 def = req.sym_out; 3083 defobj = req.defobj_out; 3084 } 3085 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3086 handle == RTLD_SELF) { /* ... caller included */ 3087 if (handle == RTLD_NEXT) 3088 obj = obj->next; 3089 for (; obj != NULL; obj = obj->next) { 3090 res = symlook_obj(&req, obj); 3091 if (res == 0) { 3092 if (def == NULL || 3093 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3094 def = req.sym_out; 3095 defobj = req.defobj_out; 3096 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3097 break; 3098 } 3099 } 3100 } 3101 /* 3102 * Search the dynamic linker itself, and possibly resolve the 3103 * symbol from there. This is how the application links to 3104 * dynamic linker services such as dlopen. 3105 */ 3106 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3107 res = symlook_obj(&req, &obj_rtld); 3108 if (res == 0) { 3109 def = req.sym_out; 3110 defobj = req.defobj_out; 3111 } 3112 } 3113 } else { 3114 assert(handle == RTLD_DEFAULT); 3115 res = symlook_default(&req, obj); 3116 if (res == 0) { 3117 defobj = req.defobj_out; 3118 def = req.sym_out; 3119 } 3120 } 3121 } else { 3122 if ((obj = dlcheck(handle)) == NULL) { 3123 lock_release(rtld_bind_lock, &lockstate); 3124 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3125 return NULL; 3126 } 3127 3128 donelist_init(&donelist); 3129 if (obj->mainprog) { 3130 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3131 res = symlook_global(&req, &donelist); 3132 if (res == 0) { 3133 def = req.sym_out; 3134 defobj = req.defobj_out; 3135 } 3136 /* 3137 * Search the dynamic linker itself, and possibly resolve the 3138 * symbol from there. This is how the application links to 3139 * dynamic linker services such as dlopen. 3140 */ 3141 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3142 res = symlook_obj(&req, &obj_rtld); 3143 if (res == 0) { 3144 def = req.sym_out; 3145 defobj = req.defobj_out; 3146 } 3147 } 3148 } 3149 else { 3150 /* Search the whole DAG rooted at the given object. */ 3151 res = symlook_list(&req, &obj->dagmembers, &donelist); 3152 if (res == 0) { 3153 def = req.sym_out; 3154 defobj = req.defobj_out; 3155 } 3156 } 3157 } 3158 3159 if (def != NULL) { 3160 lock_release(rtld_bind_lock, &lockstate); 3161 3162 /* 3163 * The value required by the caller is derived from the value 3164 * of the symbol. For the ia64 architecture, we need to 3165 * construct a function descriptor which the caller can use to 3166 * call the function with the right 'gp' value. For other 3167 * architectures and for non-functions, the value is simply 3168 * the relocated value of the symbol. 3169 */ 3170 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3171 sym = make_function_pointer(def, defobj); 3172 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3173 sym = rtld_resolve_ifunc(defobj, def); 3174 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3175#ifdef __ia64__ 3176 return (__tls_get_addr(defobj->tlsindex, def->st_value)); 3177#else 3178 ti.ti_module = defobj->tlsindex; 3179 ti.ti_offset = def->st_value; 3180 sym = __tls_get_addr(&ti); 3181#endif 3182 } else 3183 sym = defobj->relocbase + def->st_value; 3184 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3185 return (sym); 3186 } 3187 3188 _rtld_error("Undefined symbol \"%s\"", name); 3189 lock_release(rtld_bind_lock, &lockstate); 3190 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3191 return NULL; 3192} 3193 3194void * 3195dlsym(void *handle, const char *name) 3196{ 3197 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3198 SYMLOOK_DLSYM); 3199} 3200 3201dlfunc_t 3202dlfunc(void *handle, const char *name) 3203{ 3204 union { 3205 void *d; 3206 dlfunc_t f; 3207 } rv; 3208 3209 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3210 SYMLOOK_DLSYM); 3211 return (rv.f); 3212} 3213 3214void * 3215dlvsym(void *handle, const char *name, const char *version) 3216{ 3217 Ver_Entry ventry; 3218 3219 ventry.name = version; 3220 ventry.file = NULL; 3221 ventry.hash = elf_hash(version); 3222 ventry.flags= 0; 3223 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3224 SYMLOOK_DLSYM); 3225} 3226 3227int 3228_rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3229{ 3230 const Obj_Entry *obj; 3231 RtldLockState lockstate; 3232 3233 rlock_acquire(rtld_bind_lock, &lockstate); 3234 obj = obj_from_addr(addr); 3235 if (obj == NULL) { 3236 _rtld_error("No shared object contains address"); 3237 lock_release(rtld_bind_lock, &lockstate); 3238 return (0); 3239 } 3240 rtld_fill_dl_phdr_info(obj, phdr_info); 3241 lock_release(rtld_bind_lock, &lockstate); 3242 return (1); 3243} 3244 3245int 3246dladdr(const void *addr, Dl_info *info) 3247{ 3248 const Obj_Entry *obj; 3249 const Elf_Sym *def; 3250 void *symbol_addr; 3251 unsigned long symoffset; 3252 RtldLockState lockstate; 3253 3254 rlock_acquire(rtld_bind_lock, &lockstate); 3255 obj = obj_from_addr(addr); 3256 if (obj == NULL) { 3257 _rtld_error("No shared object contains address"); 3258 lock_release(rtld_bind_lock, &lockstate); 3259 return 0; 3260 } 3261 info->dli_fname = obj->path; 3262 info->dli_fbase = obj->mapbase; 3263 info->dli_saddr = (void *)0; 3264 info->dli_sname = NULL; 3265 3266 /* 3267 * Walk the symbol list looking for the symbol whose address is 3268 * closest to the address sent in. 3269 */ 3270 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3271 def = obj->symtab + symoffset; 3272 3273 /* 3274 * For skip the symbol if st_shndx is either SHN_UNDEF or 3275 * SHN_COMMON. 3276 */ 3277 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3278 continue; 3279 3280 /* 3281 * If the symbol is greater than the specified address, or if it 3282 * is further away from addr than the current nearest symbol, 3283 * then reject it. 3284 */ 3285 symbol_addr = obj->relocbase + def->st_value; 3286 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3287 continue; 3288 3289 /* Update our idea of the nearest symbol. */ 3290 info->dli_sname = obj->strtab + def->st_name; 3291 info->dli_saddr = symbol_addr; 3292 3293 /* Exact match? */ 3294 if (info->dli_saddr == addr) 3295 break; 3296 } 3297 lock_release(rtld_bind_lock, &lockstate); 3298 return 1; 3299} 3300 3301int 3302dlinfo(void *handle, int request, void *p) 3303{ 3304 const Obj_Entry *obj; 3305 RtldLockState lockstate; 3306 int error; 3307 3308 rlock_acquire(rtld_bind_lock, &lockstate); 3309 3310 if (handle == NULL || handle == RTLD_SELF) { 3311 void *retaddr; 3312 3313 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3314 if ((obj = obj_from_addr(retaddr)) == NULL) 3315 _rtld_error("Cannot determine caller's shared object"); 3316 } else 3317 obj = dlcheck(handle); 3318 3319 if (obj == NULL) { 3320 lock_release(rtld_bind_lock, &lockstate); 3321 return (-1); 3322 } 3323 3324 error = 0; 3325 switch (request) { 3326 case RTLD_DI_LINKMAP: 3327 *((struct link_map const **)p) = &obj->linkmap; 3328 break; 3329 case RTLD_DI_ORIGIN: 3330 error = rtld_dirname(obj->path, p); 3331 break; 3332 3333 case RTLD_DI_SERINFOSIZE: 3334 case RTLD_DI_SERINFO: 3335 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3336 break; 3337 3338 default: 3339 _rtld_error("Invalid request %d passed to dlinfo()", request); 3340 error = -1; 3341 } 3342 3343 lock_release(rtld_bind_lock, &lockstate); 3344 3345 return (error); 3346} 3347 3348static void 3349rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3350{ 3351 3352 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3353 phdr_info->dlpi_name = obj->path; 3354 phdr_info->dlpi_phdr = obj->phdr; 3355 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3356 phdr_info->dlpi_tls_modid = obj->tlsindex; 3357 phdr_info->dlpi_tls_data = obj->tlsinit; 3358 phdr_info->dlpi_adds = obj_loads; 3359 phdr_info->dlpi_subs = obj_loads - obj_count; 3360} 3361 3362int 3363dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3364{ 3365 struct dl_phdr_info phdr_info; 3366 const Obj_Entry *obj; 3367 RtldLockState bind_lockstate, phdr_lockstate; 3368 int error; 3369 3370 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3371 rlock_acquire(rtld_bind_lock, &bind_lockstate); 3372 3373 error = 0; 3374 3375 for (obj = obj_list; obj != NULL; obj = obj->next) { 3376 rtld_fill_dl_phdr_info(obj, &phdr_info); 3377 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0) 3378 break; 3379 3380 } 3381 lock_release(rtld_bind_lock, &bind_lockstate); 3382 lock_release(rtld_phdr_lock, &phdr_lockstate); 3383 3384 return (error); 3385} 3386 3387static void * 3388fill_search_info(const char *dir, size_t dirlen, void *param) 3389{ 3390 struct fill_search_info_args *arg; 3391 3392 arg = param; 3393 3394 if (arg->request == RTLD_DI_SERINFOSIZE) { 3395 arg->serinfo->dls_cnt ++; 3396 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3397 } else { 3398 struct dl_serpath *s_entry; 3399 3400 s_entry = arg->serpath; 3401 s_entry->dls_name = arg->strspace; 3402 s_entry->dls_flags = arg->flags; 3403 3404 strncpy(arg->strspace, dir, dirlen); 3405 arg->strspace[dirlen] = '\0'; 3406 3407 arg->strspace += dirlen + 1; 3408 arg->serpath++; 3409 } 3410 3411 return (NULL); 3412} 3413 3414static int 3415do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3416{ 3417 struct dl_serinfo _info; 3418 struct fill_search_info_args args; 3419 3420 args.request = RTLD_DI_SERINFOSIZE; 3421 args.serinfo = &_info; 3422 3423 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3424 _info.dls_cnt = 0; 3425 3426 path_enumerate(obj->rpath, fill_search_info, &args); 3427 path_enumerate(ld_library_path, fill_search_info, &args); 3428 path_enumerate(obj->runpath, fill_search_info, &args); 3429 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args); 3430 if (!obj->z_nodeflib) 3431 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 3432 3433 3434 if (request == RTLD_DI_SERINFOSIZE) { 3435 info->dls_size = _info.dls_size; 3436 info->dls_cnt = _info.dls_cnt; 3437 return (0); 3438 } 3439 3440 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3441 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3442 return (-1); 3443 } 3444 3445 args.request = RTLD_DI_SERINFO; 3446 args.serinfo = info; 3447 args.serpath = &info->dls_serpath[0]; 3448 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3449 3450 args.flags = LA_SER_RUNPATH; 3451 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 3452 return (-1); 3453 3454 args.flags = LA_SER_LIBPATH; 3455 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 3456 return (-1); 3457 3458 args.flags = LA_SER_RUNPATH; 3459 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL) 3460 return (-1); 3461 3462 args.flags = LA_SER_CONFIG; 3463 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args) 3464 != NULL) 3465 return (-1); 3466 3467 args.flags = LA_SER_DEFAULT; 3468 if (!obj->z_nodeflib && 3469 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 3470 return (-1); 3471 return (0); 3472} 3473 3474static int 3475rtld_dirname(const char *path, char *bname) 3476{ 3477 const char *endp; 3478 3479 /* Empty or NULL string gets treated as "." */ 3480 if (path == NULL || *path == '\0') { 3481 bname[0] = '.'; 3482 bname[1] = '\0'; 3483 return (0); 3484 } 3485 3486 /* Strip trailing slashes */ 3487 endp = path + strlen(path) - 1; 3488 while (endp > path && *endp == '/') 3489 endp--; 3490 3491 /* Find the start of the dir */ 3492 while (endp > path && *endp != '/') 3493 endp--; 3494 3495 /* Either the dir is "/" or there are no slashes */ 3496 if (endp == path) { 3497 bname[0] = *endp == '/' ? '/' : '.'; 3498 bname[1] = '\0'; 3499 return (0); 3500 } else { 3501 do { 3502 endp--; 3503 } while (endp > path && *endp == '/'); 3504 } 3505 3506 if (endp - path + 2 > PATH_MAX) 3507 { 3508 _rtld_error("Filename is too long: %s", path); 3509 return(-1); 3510 } 3511 3512 strncpy(bname, path, endp - path + 1); 3513 bname[endp - path + 1] = '\0'; 3514 return (0); 3515} 3516 3517static int 3518rtld_dirname_abs(const char *path, char *base) 3519{ 3520 char *last; 3521 3522 if (realpath(path, base) == NULL) 3523 return (-1); 3524 dbg("%s -> %s", path, base); 3525 last = strrchr(base, '/'); 3526 if (last == NULL) 3527 return (-1); 3528 if (last != base) 3529 *last = '\0'; 3530 return (0); 3531} 3532 3533static void 3534linkmap_add(Obj_Entry *obj) 3535{ 3536 struct link_map *l = &obj->linkmap; 3537 struct link_map *prev; 3538 3539 obj->linkmap.l_name = obj->path; 3540 obj->linkmap.l_addr = obj->mapbase; 3541 obj->linkmap.l_ld = obj->dynamic; 3542#ifdef __mips__ 3543 /* GDB needs load offset on MIPS to use the symbols */ 3544 obj->linkmap.l_offs = obj->relocbase; 3545#endif 3546 3547 if (r_debug.r_map == NULL) { 3548 r_debug.r_map = l; 3549 return; 3550 } 3551 3552 /* 3553 * Scan to the end of the list, but not past the entry for the 3554 * dynamic linker, which we want to keep at the very end. 3555 */ 3556 for (prev = r_debug.r_map; 3557 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3558 prev = prev->l_next) 3559 ; 3560 3561 /* Link in the new entry. */ 3562 l->l_prev = prev; 3563 l->l_next = prev->l_next; 3564 if (l->l_next != NULL) 3565 l->l_next->l_prev = l; 3566 prev->l_next = l; 3567} 3568 3569static void 3570linkmap_delete(Obj_Entry *obj) 3571{ 3572 struct link_map *l = &obj->linkmap; 3573 3574 if (l->l_prev == NULL) { 3575 if ((r_debug.r_map = l->l_next) != NULL) 3576 l->l_next->l_prev = NULL; 3577 return; 3578 } 3579 3580 if ((l->l_prev->l_next = l->l_next) != NULL) 3581 l->l_next->l_prev = l->l_prev; 3582} 3583 3584/* 3585 * Function for the debugger to set a breakpoint on to gain control. 3586 * 3587 * The two parameters allow the debugger to easily find and determine 3588 * what the runtime loader is doing and to whom it is doing it. 3589 * 3590 * When the loadhook trap is hit (r_debug_state, set at program 3591 * initialization), the arguments can be found on the stack: 3592 * 3593 * +8 struct link_map *m 3594 * +4 struct r_debug *rd 3595 * +0 RetAddr 3596 */ 3597void 3598r_debug_state(struct r_debug* rd, struct link_map *m) 3599{ 3600 /* 3601 * The following is a hack to force the compiler to emit calls to 3602 * this function, even when optimizing. If the function is empty, 3603 * the compiler is not obliged to emit any code for calls to it, 3604 * even when marked __noinline. However, gdb depends on those 3605 * calls being made. 3606 */ 3607 __compiler_membar(); 3608} 3609 3610/* 3611 * A function called after init routines have completed. This can be used to 3612 * break before a program's entry routine is called, and can be used when 3613 * main is not available in the symbol table. 3614 */ 3615void 3616_r_debug_postinit(struct link_map *m) 3617{ 3618 3619 /* See r_debug_state(). */ 3620 __compiler_membar(); 3621} 3622 3623/* 3624 * Get address of the pointer variable in the main program. 3625 * Prefer non-weak symbol over the weak one. 3626 */ 3627static const void ** 3628get_program_var_addr(const char *name, RtldLockState *lockstate) 3629{ 3630 SymLook req; 3631 DoneList donelist; 3632 3633 symlook_init(&req, name); 3634 req.lockstate = lockstate; 3635 donelist_init(&donelist); 3636 if (symlook_global(&req, &donelist) != 0) 3637 return (NULL); 3638 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 3639 return ((const void **)make_function_pointer(req.sym_out, 3640 req.defobj_out)); 3641 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 3642 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 3643 else 3644 return ((const void **)(req.defobj_out->relocbase + 3645 req.sym_out->st_value)); 3646} 3647 3648/* 3649 * Set a pointer variable in the main program to the given value. This 3650 * is used to set key variables such as "environ" before any of the 3651 * init functions are called. 3652 */ 3653static void 3654set_program_var(const char *name, const void *value) 3655{ 3656 const void **addr; 3657 3658 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 3659 dbg("\"%s\": *%p <-- %p", name, addr, value); 3660 *addr = value; 3661 } 3662} 3663 3664/* 3665 * Search the global objects, including dependencies and main object, 3666 * for the given symbol. 3667 */ 3668static int 3669symlook_global(SymLook *req, DoneList *donelist) 3670{ 3671 SymLook req1; 3672 const Objlist_Entry *elm; 3673 int res; 3674 3675 symlook_init_from_req(&req1, req); 3676 3677 /* Search all objects loaded at program start up. */ 3678 if (req->defobj_out == NULL || 3679 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3680 res = symlook_list(&req1, &list_main, donelist); 3681 if (res == 0 && (req->defobj_out == NULL || 3682 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3683 req->sym_out = req1.sym_out; 3684 req->defobj_out = req1.defobj_out; 3685 assert(req->defobj_out != NULL); 3686 } 3687 } 3688 3689 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 3690 STAILQ_FOREACH(elm, &list_global, link) { 3691 if (req->defobj_out != NULL && 3692 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3693 break; 3694 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 3695 if (res == 0 && (req->defobj_out == NULL || 3696 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3697 req->sym_out = req1.sym_out; 3698 req->defobj_out = req1.defobj_out; 3699 assert(req->defobj_out != NULL); 3700 } 3701 } 3702 3703 return (req->sym_out != NULL ? 0 : ESRCH); 3704} 3705 3706/* 3707 * Given a symbol name in a referencing object, find the corresponding 3708 * definition of the symbol. Returns a pointer to the symbol, or NULL if 3709 * no definition was found. Returns a pointer to the Obj_Entry of the 3710 * defining object via the reference parameter DEFOBJ_OUT. 3711 */ 3712static int 3713symlook_default(SymLook *req, const Obj_Entry *refobj) 3714{ 3715 DoneList donelist; 3716 const Objlist_Entry *elm; 3717 SymLook req1; 3718 int res; 3719 3720 donelist_init(&donelist); 3721 symlook_init_from_req(&req1, req); 3722 3723 /* Look first in the referencing object if linked symbolically. */ 3724 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 3725 res = symlook_obj(&req1, refobj); 3726 if (res == 0) { 3727 req->sym_out = req1.sym_out; 3728 req->defobj_out = req1.defobj_out; 3729 assert(req->defobj_out != NULL); 3730 } 3731 } 3732 3733 symlook_global(req, &donelist); 3734 3735 /* Search all dlopened DAGs containing the referencing object. */ 3736 STAILQ_FOREACH(elm, &refobj->dldags, link) { 3737 if (req->sym_out != NULL && 3738 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3739 break; 3740 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 3741 if (res == 0 && (req->sym_out == NULL || 3742 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3743 req->sym_out = req1.sym_out; 3744 req->defobj_out = req1.defobj_out; 3745 assert(req->defobj_out != NULL); 3746 } 3747 } 3748 3749 /* 3750 * Search the dynamic linker itself, and possibly resolve the 3751 * symbol from there. This is how the application links to 3752 * dynamic linker services such as dlopen. 3753 */ 3754 if (req->sym_out == NULL || 3755 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3756 res = symlook_obj(&req1, &obj_rtld); 3757 if (res == 0) { 3758 req->sym_out = req1.sym_out; 3759 req->defobj_out = req1.defobj_out; 3760 assert(req->defobj_out != NULL); 3761 } 3762 } 3763 3764 return (req->sym_out != NULL ? 0 : ESRCH); 3765} 3766 3767static int 3768symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 3769{ 3770 const Elf_Sym *def; 3771 const Obj_Entry *defobj; 3772 const Objlist_Entry *elm; 3773 SymLook req1; 3774 int res; 3775 3776 def = NULL; 3777 defobj = NULL; 3778 STAILQ_FOREACH(elm, objlist, link) { 3779 if (donelist_check(dlp, elm->obj)) 3780 continue; 3781 symlook_init_from_req(&req1, req); 3782 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 3783 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3784 def = req1.sym_out; 3785 defobj = req1.defobj_out; 3786 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3787 break; 3788 } 3789 } 3790 } 3791 if (def != NULL) { 3792 req->sym_out = def; 3793 req->defobj_out = defobj; 3794 return (0); 3795 } 3796 return (ESRCH); 3797} 3798 3799/* 3800 * Search the chain of DAGS cointed to by the given Needed_Entry 3801 * for a symbol of the given name. Each DAG is scanned completely 3802 * before advancing to the next one. Returns a pointer to the symbol, 3803 * or NULL if no definition was found. 3804 */ 3805static int 3806symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 3807{ 3808 const Elf_Sym *def; 3809 const Needed_Entry *n; 3810 const Obj_Entry *defobj; 3811 SymLook req1; 3812 int res; 3813 3814 def = NULL; 3815 defobj = NULL; 3816 symlook_init_from_req(&req1, req); 3817 for (n = needed; n != NULL; n = n->next) { 3818 if (n->obj == NULL || 3819 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 3820 continue; 3821 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3822 def = req1.sym_out; 3823 defobj = req1.defobj_out; 3824 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3825 break; 3826 } 3827 } 3828 if (def != NULL) { 3829 req->sym_out = def; 3830 req->defobj_out = defobj; 3831 return (0); 3832 } 3833 return (ESRCH); 3834} 3835 3836/* 3837 * Search the symbol table of a single shared object for a symbol of 3838 * the given name and version, if requested. Returns a pointer to the 3839 * symbol, or NULL if no definition was found. If the object is 3840 * filter, return filtered symbol from filtee. 3841 * 3842 * The symbol's hash value is passed in for efficiency reasons; that 3843 * eliminates many recomputations of the hash value. 3844 */ 3845int 3846symlook_obj(SymLook *req, const Obj_Entry *obj) 3847{ 3848 DoneList donelist; 3849 SymLook req1; 3850 int flags, res, mres; 3851 3852 /* 3853 * If there is at least one valid hash at this point, we prefer to 3854 * use the faster GNU version if available. 3855 */ 3856 if (obj->valid_hash_gnu) 3857 mres = symlook_obj1_gnu(req, obj); 3858 else if (obj->valid_hash_sysv) 3859 mres = symlook_obj1_sysv(req, obj); 3860 else 3861 return (EINVAL); 3862 3863 if (mres == 0) { 3864 if (obj->needed_filtees != NULL) { 3865 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3866 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3867 donelist_init(&donelist); 3868 symlook_init_from_req(&req1, req); 3869 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 3870 if (res == 0) { 3871 req->sym_out = req1.sym_out; 3872 req->defobj_out = req1.defobj_out; 3873 } 3874 return (res); 3875 } 3876 if (obj->needed_aux_filtees != NULL) { 3877 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3878 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3879 donelist_init(&donelist); 3880 symlook_init_from_req(&req1, req); 3881 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 3882 if (res == 0) { 3883 req->sym_out = req1.sym_out; 3884 req->defobj_out = req1.defobj_out; 3885 return (res); 3886 } 3887 } 3888 } 3889 return (mres); 3890} 3891 3892/* Symbol match routine common to both hash functions */ 3893static bool 3894matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 3895 const unsigned long symnum) 3896{ 3897 Elf_Versym verndx; 3898 const Elf_Sym *symp; 3899 const char *strp; 3900 3901 symp = obj->symtab + symnum; 3902 strp = obj->strtab + symp->st_name; 3903 3904 switch (ELF_ST_TYPE(symp->st_info)) { 3905 case STT_FUNC: 3906 case STT_NOTYPE: 3907 case STT_OBJECT: 3908 case STT_COMMON: 3909 case STT_GNU_IFUNC: 3910 if (symp->st_value == 0) 3911 return (false); 3912 /* fallthrough */ 3913 case STT_TLS: 3914 if (symp->st_shndx != SHN_UNDEF) 3915 break; 3916#ifndef __mips__ 3917 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 3918 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 3919 break; 3920 /* fallthrough */ 3921#endif 3922 default: 3923 return (false); 3924 } 3925 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 3926 return (false); 3927 3928 if (req->ventry == NULL) { 3929 if (obj->versyms != NULL) { 3930 verndx = VER_NDX(obj->versyms[symnum]); 3931 if (verndx > obj->vernum) { 3932 _rtld_error( 3933 "%s: symbol %s references wrong version %d", 3934 obj->path, obj->strtab + symnum, verndx); 3935 return (false); 3936 } 3937 /* 3938 * If we are not called from dlsym (i.e. this 3939 * is a normal relocation from unversioned 3940 * binary), accept the symbol immediately if 3941 * it happens to have first version after this 3942 * shared object became versioned. Otherwise, 3943 * if symbol is versioned and not hidden, 3944 * remember it. If it is the only symbol with 3945 * this name exported by the shared object, it 3946 * will be returned as a match by the calling 3947 * function. If symbol is global (verndx < 2) 3948 * accept it unconditionally. 3949 */ 3950 if ((req->flags & SYMLOOK_DLSYM) == 0 && 3951 verndx == VER_NDX_GIVEN) { 3952 result->sym_out = symp; 3953 return (true); 3954 } 3955 else if (verndx >= VER_NDX_GIVEN) { 3956 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 3957 == 0) { 3958 if (result->vsymp == NULL) 3959 result->vsymp = symp; 3960 result->vcount++; 3961 } 3962 return (false); 3963 } 3964 } 3965 result->sym_out = symp; 3966 return (true); 3967 } 3968 if (obj->versyms == NULL) { 3969 if (object_match_name(obj, req->ventry->name)) { 3970 _rtld_error("%s: object %s should provide version %s " 3971 "for symbol %s", obj_rtld.path, obj->path, 3972 req->ventry->name, obj->strtab + symnum); 3973 return (false); 3974 } 3975 } else { 3976 verndx = VER_NDX(obj->versyms[symnum]); 3977 if (verndx > obj->vernum) { 3978 _rtld_error("%s: symbol %s references wrong version %d", 3979 obj->path, obj->strtab + symnum, verndx); 3980 return (false); 3981 } 3982 if (obj->vertab[verndx].hash != req->ventry->hash || 3983 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 3984 /* 3985 * Version does not match. Look if this is a 3986 * global symbol and if it is not hidden. If 3987 * global symbol (verndx < 2) is available, 3988 * use it. Do not return symbol if we are 3989 * called by dlvsym, because dlvsym looks for 3990 * a specific version and default one is not 3991 * what dlvsym wants. 3992 */ 3993 if ((req->flags & SYMLOOK_DLSYM) || 3994 (verndx >= VER_NDX_GIVEN) || 3995 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 3996 return (false); 3997 } 3998 } 3999 result->sym_out = symp; 4000 return (true); 4001} 4002 4003/* 4004 * Search for symbol using SysV hash function. 4005 * obj->buckets is known not to be NULL at this point; the test for this was 4006 * performed with the obj->valid_hash_sysv assignment. 4007 */ 4008static int 4009symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4010{ 4011 unsigned long symnum; 4012 Sym_Match_Result matchres; 4013 4014 matchres.sym_out = NULL; 4015 matchres.vsymp = NULL; 4016 matchres.vcount = 0; 4017 4018 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4019 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4020 if (symnum >= obj->nchains) 4021 return (ESRCH); /* Bad object */ 4022 4023 if (matched_symbol(req, obj, &matchres, symnum)) { 4024 req->sym_out = matchres.sym_out; 4025 req->defobj_out = obj; 4026 return (0); 4027 } 4028 } 4029 if (matchres.vcount == 1) { 4030 req->sym_out = matchres.vsymp; 4031 req->defobj_out = obj; 4032 return (0); 4033 } 4034 return (ESRCH); 4035} 4036 4037/* Search for symbol using GNU hash function */ 4038static int 4039symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4040{ 4041 Elf_Addr bloom_word; 4042 const Elf32_Word *hashval; 4043 Elf32_Word bucket; 4044 Sym_Match_Result matchres; 4045 unsigned int h1, h2; 4046 unsigned long symnum; 4047 4048 matchres.sym_out = NULL; 4049 matchres.vsymp = NULL; 4050 matchres.vcount = 0; 4051 4052 /* Pick right bitmask word from Bloom filter array */ 4053 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4054 obj->maskwords_bm_gnu]; 4055 4056 /* Calculate modulus word size of gnu hash and its derivative */ 4057 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4058 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4059 4060 /* Filter out the "definitely not in set" queries */ 4061 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4062 return (ESRCH); 4063 4064 /* Locate hash chain and corresponding value element*/ 4065 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4066 if (bucket == 0) 4067 return (ESRCH); 4068 hashval = &obj->chain_zero_gnu[bucket]; 4069 do { 4070 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4071 symnum = hashval - obj->chain_zero_gnu; 4072 if (matched_symbol(req, obj, &matchres, symnum)) { 4073 req->sym_out = matchres.sym_out; 4074 req->defobj_out = obj; 4075 return (0); 4076 } 4077 } 4078 } while ((*hashval++ & 1) == 0); 4079 if (matchres.vcount == 1) { 4080 req->sym_out = matchres.vsymp; 4081 req->defobj_out = obj; 4082 return (0); 4083 } 4084 return (ESRCH); 4085} 4086 4087static void 4088trace_loaded_objects(Obj_Entry *obj) 4089{ 4090 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4091 int c; 4092 4093 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 4094 main_local = ""; 4095 4096 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL) 4097 fmt1 = "\t%o => %p (%x)\n"; 4098 4099 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL) 4100 fmt2 = "\t%o (%x)\n"; 4101 4102 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL"); 4103 4104 for (; obj; obj = obj->next) { 4105 Needed_Entry *needed; 4106 char *name, *path; 4107 bool is_lib; 4108 4109 if (list_containers && obj->needed != NULL) 4110 rtld_printf("%s:\n", obj->path); 4111 for (needed = obj->needed; needed; needed = needed->next) { 4112 if (needed->obj != NULL) { 4113 if (needed->obj->traced && !list_containers) 4114 continue; 4115 needed->obj->traced = true; 4116 path = needed->obj->path; 4117 } else 4118 path = "not found"; 4119 4120 name = (char *)obj->strtab + needed->name; 4121 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4122 4123 fmt = is_lib ? fmt1 : fmt2; 4124 while ((c = *fmt++) != '\0') { 4125 switch (c) { 4126 default: 4127 rtld_putchar(c); 4128 continue; 4129 case '\\': 4130 switch (c = *fmt) { 4131 case '\0': 4132 continue; 4133 case 'n': 4134 rtld_putchar('\n'); 4135 break; 4136 case 't': 4137 rtld_putchar('\t'); 4138 break; 4139 } 4140 break; 4141 case '%': 4142 switch (c = *fmt) { 4143 case '\0': 4144 continue; 4145 case '%': 4146 default: 4147 rtld_putchar(c); 4148 break; 4149 case 'A': 4150 rtld_putstr(main_local); 4151 break; 4152 case 'a': 4153 rtld_putstr(obj_main->path); 4154 break; 4155 case 'o': 4156 rtld_putstr(name); 4157 break; 4158#if 0 4159 case 'm': 4160 rtld_printf("%d", sodp->sod_major); 4161 break; 4162 case 'n': 4163 rtld_printf("%d", sodp->sod_minor); 4164 break; 4165#endif 4166 case 'p': 4167 rtld_putstr(path); 4168 break; 4169 case 'x': 4170 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4171 0); 4172 break; 4173 } 4174 break; 4175 } 4176 ++fmt; 4177 } 4178 } 4179 } 4180} 4181 4182/* 4183 * Unload a dlopened object and its dependencies from memory and from 4184 * our data structures. It is assumed that the DAG rooted in the 4185 * object has already been unreferenced, and that the object has a 4186 * reference count of 0. 4187 */ 4188static void 4189unload_object(Obj_Entry *root) 4190{ 4191 Obj_Entry *obj; 4192 Obj_Entry **linkp; 4193 4194 assert(root->refcount == 0); 4195 4196 /* 4197 * Pass over the DAG removing unreferenced objects from 4198 * appropriate lists. 4199 */ 4200 unlink_object(root); 4201 4202 /* Unmap all objects that are no longer referenced. */ 4203 linkp = &obj_list->next; 4204 while ((obj = *linkp) != NULL) { 4205 if (obj->refcount == 0) { 4206 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 4207 obj->path); 4208 dbg("unloading \"%s\"", obj->path); 4209 unload_filtees(root); 4210 munmap(obj->mapbase, obj->mapsize); 4211 linkmap_delete(obj); 4212 *linkp = obj->next; 4213 obj_count--; 4214 obj_free(obj); 4215 } else 4216 linkp = &obj->next; 4217 } 4218 obj_tail = linkp; 4219} 4220 4221static void 4222unlink_object(Obj_Entry *root) 4223{ 4224 Objlist_Entry *elm; 4225 4226 if (root->refcount == 0) { 4227 /* Remove the object from the RTLD_GLOBAL list. */ 4228 objlist_remove(&list_global, root); 4229 4230 /* Remove the object from all objects' DAG lists. */ 4231 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4232 objlist_remove(&elm->obj->dldags, root); 4233 if (elm->obj != root) 4234 unlink_object(elm->obj); 4235 } 4236 } 4237} 4238 4239static void 4240ref_dag(Obj_Entry *root) 4241{ 4242 Objlist_Entry *elm; 4243 4244 assert(root->dag_inited); 4245 STAILQ_FOREACH(elm, &root->dagmembers, link) 4246 elm->obj->refcount++; 4247} 4248 4249static void 4250unref_dag(Obj_Entry *root) 4251{ 4252 Objlist_Entry *elm; 4253 4254 assert(root->dag_inited); 4255 STAILQ_FOREACH(elm, &root->dagmembers, link) 4256 elm->obj->refcount--; 4257} 4258 4259/* 4260 * Common code for MD __tls_get_addr(). 4261 */ 4262static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4263static void * 4264tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4265{ 4266 Elf_Addr *newdtv, *dtv; 4267 RtldLockState lockstate; 4268 int to_copy; 4269 4270 dtv = *dtvp; 4271 /* Check dtv generation in case new modules have arrived */ 4272 if (dtv[0] != tls_dtv_generation) { 4273 wlock_acquire(rtld_bind_lock, &lockstate); 4274 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4275 to_copy = dtv[1]; 4276 if (to_copy > tls_max_index) 4277 to_copy = tls_max_index; 4278 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4279 newdtv[0] = tls_dtv_generation; 4280 newdtv[1] = tls_max_index; 4281 free(dtv); 4282 lock_release(rtld_bind_lock, &lockstate); 4283 dtv = *dtvp = newdtv; 4284 } 4285 4286 /* Dynamically allocate module TLS if necessary */ 4287 if (dtv[index + 1] == 0) { 4288 /* Signal safe, wlock will block out signals. */ 4289 wlock_acquire(rtld_bind_lock, &lockstate); 4290 if (!dtv[index + 1]) 4291 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4292 lock_release(rtld_bind_lock, &lockstate); 4293 } 4294 return ((void *)(dtv[index + 1] + offset)); 4295} 4296 4297void * 4298tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4299{ 4300 Elf_Addr *dtv; 4301 4302 dtv = *dtvp; 4303 /* Check dtv generation in case new modules have arrived */ 4304 if (__predict_true(dtv[0] == tls_dtv_generation && 4305 dtv[index + 1] != 0)) 4306 return ((void *)(dtv[index + 1] + offset)); 4307 return (tls_get_addr_slow(dtvp, index, offset)); 4308} 4309 4310#if defined(__arm__) || defined(__ia64__) || defined(__mips__) || defined(__powerpc__) 4311 4312/* 4313 * Allocate Static TLS using the Variant I method. 4314 */ 4315void * 4316allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4317{ 4318 Obj_Entry *obj; 4319 char *tcb; 4320 Elf_Addr **tls; 4321 Elf_Addr *dtv; 4322 Elf_Addr addr; 4323 int i; 4324 4325 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4326 return (oldtcb); 4327 4328 assert(tcbsize >= TLS_TCB_SIZE); 4329 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 4330 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 4331 4332 if (oldtcb != NULL) { 4333 memcpy(tls, oldtcb, tls_static_space); 4334 free(oldtcb); 4335 4336 /* Adjust the DTV. */ 4337 dtv = tls[0]; 4338 for (i = 0; i < dtv[1]; i++) { 4339 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4340 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4341 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 4342 } 4343 } 4344 } else { 4345 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4346 tls[0] = dtv; 4347 dtv[0] = tls_dtv_generation; 4348 dtv[1] = tls_max_index; 4349 4350 for (obj = objs; obj; obj = obj->next) { 4351 if (obj->tlsoffset > 0) { 4352 addr = (Elf_Addr)tls + obj->tlsoffset; 4353 if (obj->tlsinitsize > 0) 4354 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4355 if (obj->tlssize > obj->tlsinitsize) 4356 memset((void*) (addr + obj->tlsinitsize), 0, 4357 obj->tlssize - obj->tlsinitsize); 4358 dtv[obj->tlsindex + 1] = addr; 4359 } 4360 } 4361 } 4362 4363 return (tcb); 4364} 4365 4366void 4367free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4368{ 4369 Elf_Addr *dtv; 4370 Elf_Addr tlsstart, tlsend; 4371 int dtvsize, i; 4372 4373 assert(tcbsize >= TLS_TCB_SIZE); 4374 4375 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 4376 tlsend = tlsstart + tls_static_space; 4377 4378 dtv = *(Elf_Addr **)tlsstart; 4379 dtvsize = dtv[1]; 4380 for (i = 0; i < dtvsize; i++) { 4381 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4382 free((void*)dtv[i+2]); 4383 } 4384 } 4385 free(dtv); 4386 free(tcb); 4387} 4388 4389#endif 4390 4391#if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 4392 4393/* 4394 * Allocate Static TLS using the Variant II method. 4395 */ 4396void * 4397allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4398{ 4399 Obj_Entry *obj; 4400 size_t size, ralign; 4401 char *tls; 4402 Elf_Addr *dtv, *olddtv; 4403 Elf_Addr segbase, oldsegbase, addr; 4404 int i; 4405 4406 ralign = tcbalign; 4407 if (tls_static_max_align > ralign) 4408 ralign = tls_static_max_align; 4409 size = round(tls_static_space, ralign) + round(tcbsize, ralign); 4410 4411 assert(tcbsize >= 2*sizeof(Elf_Addr)); 4412 tls = malloc_aligned(size, ralign); 4413 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4414 4415 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign)); 4416 ((Elf_Addr*)segbase)[0] = segbase; 4417 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 4418 4419 dtv[0] = tls_dtv_generation; 4420 dtv[1] = tls_max_index; 4421 4422 if (oldtls) { 4423 /* 4424 * Copy the static TLS block over whole. 4425 */ 4426 oldsegbase = (Elf_Addr) oldtls; 4427 memcpy((void *)(segbase - tls_static_space), 4428 (const void *)(oldsegbase - tls_static_space), 4429 tls_static_space); 4430 4431 /* 4432 * If any dynamic TLS blocks have been created tls_get_addr(), 4433 * move them over. 4434 */ 4435 olddtv = ((Elf_Addr**)oldsegbase)[1]; 4436 for (i = 0; i < olddtv[1]; i++) { 4437 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 4438 dtv[i+2] = olddtv[i+2]; 4439 olddtv[i+2] = 0; 4440 } 4441 } 4442 4443 /* 4444 * We assume that this block was the one we created with 4445 * allocate_initial_tls(). 4446 */ 4447 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 4448 } else { 4449 for (obj = objs; obj; obj = obj->next) { 4450 if (obj->tlsoffset) { 4451 addr = segbase - obj->tlsoffset; 4452 memset((void*) (addr + obj->tlsinitsize), 4453 0, obj->tlssize - obj->tlsinitsize); 4454 if (obj->tlsinit) 4455 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4456 dtv[obj->tlsindex + 1] = addr; 4457 } 4458 } 4459 } 4460 4461 return (void*) segbase; 4462} 4463 4464void 4465free_tls(void *tls, size_t tcbsize, size_t tcbalign) 4466{ 4467 Elf_Addr* dtv; 4468 size_t size, ralign; 4469 int dtvsize, i; 4470 Elf_Addr tlsstart, tlsend; 4471 4472 /* 4473 * Figure out the size of the initial TLS block so that we can 4474 * find stuff which ___tls_get_addr() allocated dynamically. 4475 */ 4476 ralign = tcbalign; 4477 if (tls_static_max_align > ralign) 4478 ralign = tls_static_max_align; 4479 size = round(tls_static_space, ralign); 4480 4481 dtv = ((Elf_Addr**)tls)[1]; 4482 dtvsize = dtv[1]; 4483 tlsend = (Elf_Addr) tls; 4484 tlsstart = tlsend - size; 4485 for (i = 0; i < dtvsize; i++) { 4486 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 4487 free_aligned((void *)dtv[i + 2]); 4488 } 4489 } 4490 4491 free_aligned((void *)tlsstart); 4492 free((void*) dtv); 4493} 4494 4495#endif 4496 4497/* 4498 * Allocate TLS block for module with given index. 4499 */ 4500void * 4501allocate_module_tls(int index) 4502{ 4503 Obj_Entry* obj; 4504 char* p; 4505 4506 for (obj = obj_list; obj; obj = obj->next) { 4507 if (obj->tlsindex == index) 4508 break; 4509 } 4510 if (!obj) { 4511 _rtld_error("Can't find module with TLS index %d", index); 4512 rtld_die(); 4513 } 4514 4515 p = malloc_aligned(obj->tlssize, obj->tlsalign); 4516 memcpy(p, obj->tlsinit, obj->tlsinitsize); 4517 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 4518 4519 return p; 4520} 4521 4522bool 4523allocate_tls_offset(Obj_Entry *obj) 4524{ 4525 size_t off; 4526 4527 if (obj->tls_done) 4528 return true; 4529 4530 if (obj->tlssize == 0) { 4531 obj->tls_done = true; 4532 return true; 4533 } 4534 4535 if (obj->tlsindex == 1) 4536 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 4537 else 4538 off = calculate_tls_offset(tls_last_offset, tls_last_size, 4539 obj->tlssize, obj->tlsalign); 4540 4541 /* 4542 * If we have already fixed the size of the static TLS block, we 4543 * must stay within that size. When allocating the static TLS, we 4544 * leave a small amount of space spare to be used for dynamically 4545 * loading modules which use static TLS. 4546 */ 4547 if (tls_static_space != 0) { 4548 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 4549 return false; 4550 } else if (obj->tlsalign > tls_static_max_align) { 4551 tls_static_max_align = obj->tlsalign; 4552 } 4553 4554 tls_last_offset = obj->tlsoffset = off; 4555 tls_last_size = obj->tlssize; 4556 obj->tls_done = true; 4557 4558 return true; 4559} 4560 4561void 4562free_tls_offset(Obj_Entry *obj) 4563{ 4564 4565 /* 4566 * If we were the last thing to allocate out of the static TLS 4567 * block, we give our space back to the 'allocator'. This is a 4568 * simplistic workaround to allow libGL.so.1 to be loaded and 4569 * unloaded multiple times. 4570 */ 4571 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 4572 == calculate_tls_end(tls_last_offset, tls_last_size)) { 4573 tls_last_offset -= obj->tlssize; 4574 tls_last_size = 0; 4575 } 4576} 4577 4578void * 4579_rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 4580{ 4581 void *ret; 4582 RtldLockState lockstate; 4583 4584 wlock_acquire(rtld_bind_lock, &lockstate); 4585 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign); 4586 lock_release(rtld_bind_lock, &lockstate); 4587 return (ret); 4588} 4589 4590void 4591_rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4592{ 4593 RtldLockState lockstate; 4594 4595 wlock_acquire(rtld_bind_lock, &lockstate); 4596 free_tls(tcb, tcbsize, tcbalign); 4597 lock_release(rtld_bind_lock, &lockstate); 4598} 4599 4600static void 4601object_add_name(Obj_Entry *obj, const char *name) 4602{ 4603 Name_Entry *entry; 4604 size_t len; 4605 4606 len = strlen(name); 4607 entry = malloc(sizeof(Name_Entry) + len); 4608 4609 if (entry != NULL) { 4610 strcpy(entry->name, name); 4611 STAILQ_INSERT_TAIL(&obj->names, entry, link); 4612 } 4613} 4614 4615static int 4616object_match_name(const Obj_Entry *obj, const char *name) 4617{ 4618 Name_Entry *entry; 4619 4620 STAILQ_FOREACH(entry, &obj->names, link) { 4621 if (strcmp(name, entry->name) == 0) 4622 return (1); 4623 } 4624 return (0); 4625} 4626 4627static Obj_Entry * 4628locate_dependency(const Obj_Entry *obj, const char *name) 4629{ 4630 const Objlist_Entry *entry; 4631 const Needed_Entry *needed; 4632 4633 STAILQ_FOREACH(entry, &list_main, link) { 4634 if (object_match_name(entry->obj, name)) 4635 return entry->obj; 4636 } 4637 4638 for (needed = obj->needed; needed != NULL; needed = needed->next) { 4639 if (strcmp(obj->strtab + needed->name, name) == 0 || 4640 (needed->obj != NULL && object_match_name(needed->obj, name))) { 4641 /* 4642 * If there is DT_NEEDED for the name we are looking for, 4643 * we are all set. Note that object might not be found if 4644 * dependency was not loaded yet, so the function can 4645 * return NULL here. This is expected and handled 4646 * properly by the caller. 4647 */ 4648 return (needed->obj); 4649 } 4650 } 4651 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 4652 obj->path, name); 4653 rtld_die(); 4654} 4655 4656static int 4657check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 4658 const Elf_Vernaux *vna) 4659{ 4660 const Elf_Verdef *vd; 4661 const char *vername; 4662 4663 vername = refobj->strtab + vna->vna_name; 4664 vd = depobj->verdef; 4665 if (vd == NULL) { 4666 _rtld_error("%s: version %s required by %s not defined", 4667 depobj->path, vername, refobj->path); 4668 return (-1); 4669 } 4670 for (;;) { 4671 if (vd->vd_version != VER_DEF_CURRENT) { 4672 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4673 depobj->path, vd->vd_version); 4674 return (-1); 4675 } 4676 if (vna->vna_hash == vd->vd_hash) { 4677 const Elf_Verdaux *aux = (const Elf_Verdaux *) 4678 ((char *)vd + vd->vd_aux); 4679 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 4680 return (0); 4681 } 4682 if (vd->vd_next == 0) 4683 break; 4684 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4685 } 4686 if (vna->vna_flags & VER_FLG_WEAK) 4687 return (0); 4688 _rtld_error("%s: version %s required by %s not found", 4689 depobj->path, vername, refobj->path); 4690 return (-1); 4691} 4692 4693static int 4694rtld_verify_object_versions(Obj_Entry *obj) 4695{ 4696 const Elf_Verneed *vn; 4697 const Elf_Verdef *vd; 4698 const Elf_Verdaux *vda; 4699 const Elf_Vernaux *vna; 4700 const Obj_Entry *depobj; 4701 int maxvernum, vernum; 4702 4703 if (obj->ver_checked) 4704 return (0); 4705 obj->ver_checked = true; 4706 4707 maxvernum = 0; 4708 /* 4709 * Walk over defined and required version records and figure out 4710 * max index used by any of them. Do very basic sanity checking 4711 * while there. 4712 */ 4713 vn = obj->verneed; 4714 while (vn != NULL) { 4715 if (vn->vn_version != VER_NEED_CURRENT) { 4716 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 4717 obj->path, vn->vn_version); 4718 return (-1); 4719 } 4720 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4721 for (;;) { 4722 vernum = VER_NEED_IDX(vna->vna_other); 4723 if (vernum > maxvernum) 4724 maxvernum = vernum; 4725 if (vna->vna_next == 0) 4726 break; 4727 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4728 } 4729 if (vn->vn_next == 0) 4730 break; 4731 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4732 } 4733 4734 vd = obj->verdef; 4735 while (vd != NULL) { 4736 if (vd->vd_version != VER_DEF_CURRENT) { 4737 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4738 obj->path, vd->vd_version); 4739 return (-1); 4740 } 4741 vernum = VER_DEF_IDX(vd->vd_ndx); 4742 if (vernum > maxvernum) 4743 maxvernum = vernum; 4744 if (vd->vd_next == 0) 4745 break; 4746 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4747 } 4748 4749 if (maxvernum == 0) 4750 return (0); 4751 4752 /* 4753 * Store version information in array indexable by version index. 4754 * Verify that object version requirements are satisfied along the 4755 * way. 4756 */ 4757 obj->vernum = maxvernum + 1; 4758 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 4759 4760 vd = obj->verdef; 4761 while (vd != NULL) { 4762 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 4763 vernum = VER_DEF_IDX(vd->vd_ndx); 4764 assert(vernum <= maxvernum); 4765 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 4766 obj->vertab[vernum].hash = vd->vd_hash; 4767 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 4768 obj->vertab[vernum].file = NULL; 4769 obj->vertab[vernum].flags = 0; 4770 } 4771 if (vd->vd_next == 0) 4772 break; 4773 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4774 } 4775 4776 vn = obj->verneed; 4777 while (vn != NULL) { 4778 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 4779 if (depobj == NULL) 4780 return (-1); 4781 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4782 for (;;) { 4783 if (check_object_provided_version(obj, depobj, vna)) 4784 return (-1); 4785 vernum = VER_NEED_IDX(vna->vna_other); 4786 assert(vernum <= maxvernum); 4787 obj->vertab[vernum].hash = vna->vna_hash; 4788 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 4789 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 4790 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 4791 VER_INFO_HIDDEN : 0; 4792 if (vna->vna_next == 0) 4793 break; 4794 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4795 } 4796 if (vn->vn_next == 0) 4797 break; 4798 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4799 } 4800 return 0; 4801} 4802 4803static int 4804rtld_verify_versions(const Objlist *objlist) 4805{ 4806 Objlist_Entry *entry; 4807 int rc; 4808 4809 rc = 0; 4810 STAILQ_FOREACH(entry, objlist, link) { 4811 /* 4812 * Skip dummy objects or objects that have their version requirements 4813 * already checked. 4814 */ 4815 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 4816 continue; 4817 if (rtld_verify_object_versions(entry->obj) == -1) { 4818 rc = -1; 4819 if (ld_tracing == NULL) 4820 break; 4821 } 4822 } 4823 if (rc == 0 || ld_tracing != NULL) 4824 rc = rtld_verify_object_versions(&obj_rtld); 4825 return rc; 4826} 4827 4828const Ver_Entry * 4829fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 4830{ 4831 Elf_Versym vernum; 4832 4833 if (obj->vertab) { 4834 vernum = VER_NDX(obj->versyms[symnum]); 4835 if (vernum >= obj->vernum) { 4836 _rtld_error("%s: symbol %s has wrong verneed value %d", 4837 obj->path, obj->strtab + symnum, vernum); 4838 } else if (obj->vertab[vernum].hash != 0) { 4839 return &obj->vertab[vernum]; 4840 } 4841 } 4842 return NULL; 4843} 4844 4845int 4846_rtld_get_stack_prot(void) 4847{ 4848 4849 return (stack_prot); 4850} 4851 4852int 4853_rtld_is_dlopened(void *arg) 4854{ 4855 Obj_Entry *obj; 4856 RtldLockState lockstate; 4857 int res; 4858 4859 rlock_acquire(rtld_bind_lock, &lockstate); 4860 obj = dlcheck(arg); 4861 if (obj == NULL) 4862 obj = obj_from_addr(arg); 4863 if (obj == NULL) { 4864 _rtld_error("No shared object contains address"); 4865 lock_release(rtld_bind_lock, &lockstate); 4866 return (-1); 4867 } 4868 res = obj->dlopened ? 1 : 0; 4869 lock_release(rtld_bind_lock, &lockstate); 4870 return (res); 4871} 4872 4873static void 4874map_stacks_exec(RtldLockState *lockstate) 4875{ 4876 void (*thr_map_stacks_exec)(void); 4877 4878 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 4879 return; 4880 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 4881 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 4882 if (thr_map_stacks_exec != NULL) { 4883 stack_prot |= PROT_EXEC; 4884 thr_map_stacks_exec(); 4885 } 4886} 4887 4888void 4889symlook_init(SymLook *dst, const char *name) 4890{ 4891 4892 bzero(dst, sizeof(*dst)); 4893 dst->name = name; 4894 dst->hash = elf_hash(name); 4895 dst->hash_gnu = gnu_hash(name); 4896} 4897 4898static void 4899symlook_init_from_req(SymLook *dst, const SymLook *src) 4900{ 4901 4902 dst->name = src->name; 4903 dst->hash = src->hash; 4904 dst->hash_gnu = src->hash_gnu; 4905 dst->ventry = src->ventry; 4906 dst->flags = src->flags; 4907 dst->defobj_out = NULL; 4908 dst->sym_out = NULL; 4909 dst->lockstate = src->lockstate; 4910} 4911 4912/* 4913 * Overrides for libc_pic-provided functions. 4914 */ 4915 4916int 4917__getosreldate(void) 4918{ 4919 size_t len; 4920 int oid[2]; 4921 int error, osrel; 4922 4923 if (osreldate != 0) 4924 return (osreldate); 4925 4926 oid[0] = CTL_KERN; 4927 oid[1] = KERN_OSRELDATE; 4928 osrel = 0; 4929 len = sizeof(osrel); 4930 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 4931 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 4932 osreldate = osrel; 4933 return (osreldate); 4934} 4935 4936void 4937exit(int status) 4938{ 4939 4940 _exit(status); 4941} 4942 4943void (*__cleanup)(void); 4944int __isthreaded = 0; 4945int _thread_autoinit_dummy_decl = 1; 4946 4947/* 4948 * No unresolved symbols for rtld. 4949 */ 4950void 4951__pthread_cxa_finalize(struct dl_phdr_info *a) 4952{ 4953} 4954 4955void 4956__stack_chk_fail(void) 4957{ 4958 4959 _rtld_error("stack overflow detected; terminated"); 4960 rtld_die(); 4961} 4962__weak_reference(__stack_chk_fail, __stack_chk_fail_local); 4963 4964void 4965__chk_fail(void) 4966{ 4967 4968 _rtld_error("buffer overflow detected; terminated"); 4969 rtld_die(); 4970} 4971 4972const char * 4973rtld_strerror(int errnum) 4974{ 4975 4976 if (errnum < 0 || errnum >= sys_nerr) 4977 return ("Unknown error"); 4978 return (sys_errlist[errnum]); 4979} 4980