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 * $FreeBSD$ 29 */ 30 31 /* 32 * Dynamic linker for ELF. 33 * 34 * John Polstra <jdp@polstra.com>. 35 */ 36 37 #ifndef __GNUC__ 38 #error "GCC is needed to compile this file" 39 #endif 40 41 #include <sys/param.h> 42 #include <sys/mount.h> 43 #include <sys/mman.h> 44 #include <sys/stat.h> 45 #include <sys/sysctl.h> 46 #include <sys/utsname.h> 47 #include <sys/ktrace.h> 48 #include <sys/resident.h> 49 #include <sys/tls.h> 50 51 #include <machine/tls.h> 52 53 #include <dlfcn.h> 54 #include <err.h> 55 #include <errno.h> 56 #include <fcntl.h> 57 #include <stdarg.h> 58 #include <stdio.h> 59 #include <stdlib.h> 60 #include <string.h> 61 #include <unistd.h> 62 63 #include "debug.h" 64 #include "rtld.h" 65 #include "libmap.h" 66 #include "rtld_printf.h" 67 #include "notes.h" 68 69 #define PATH_RTLD "/usr/libexec/ld-elf.so.2" 70 #define LD_ARY_CACHE 16 71 72 /* Types. */ 73 typedef void (*func_ptr_type)(); 74 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 75 76 /* 77 * Function declarations. 78 */ 79 static int __getstatictlsextra(void); 80 static const char *_getenv_ld(const char *id); 81 static void die(void) __dead2; 82 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 83 const Elf_Dyn **, const Elf_Dyn **); 84 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *, 85 const Elf_Dyn *); 86 static void digest_dynamic(Obj_Entry *, int); 87 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 88 static void distribute_static_tls(Objlist *, RtldLockState *); 89 static Obj_Entry *dlcheck(void *); 90 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, 91 int lo_flags, int mode, RtldLockState *lockstate); 92 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 93 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 94 static bool donelist_check(DoneList *, const Obj_Entry *); 95 static void errmsg_restore(char *); 96 static char *errmsg_save(void); 97 static void *fill_search_info(const char *, size_t, void *); 98 static char *find_library(const char *, const Obj_Entry *, int *); 99 static const char *gethints(bool); 100 static void init_dag(Obj_Entry *); 101 static void init_rtld(caddr_t, Elf_Auxinfo **); 102 static void initlist_add_neededs(Needed_Entry *, Objlist *); 103 static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *); 104 static void linkmap_add(Obj_Entry *); 105 static void linkmap_delete(Obj_Entry *); 106 static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 107 static void unload_filtees(Obj_Entry *); 108 static int load_needed_objects(Obj_Entry *, int); 109 static int load_preload_objects(void); 110 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 111 static void map_stacks_exec(RtldLockState *); 112 static Obj_Entry *obj_from_addr(const void *); 113 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 114 static void objlist_call_init(Objlist *, RtldLockState *); 115 static void objlist_clear(Objlist *); 116 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 117 static void objlist_init(Objlist *); 118 static void objlist_push_head(Objlist *, Obj_Entry *); 119 static void objlist_push_tail(Objlist *, Obj_Entry *); 120 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 121 static void objlist_remove(Objlist *, Obj_Entry *); 122 static int parse_libdir(const char *); 123 static void *path_enumerate(const char *, path_enum_proc, void *); 124 static int relocate_object_dag(Obj_Entry *root, bool bind_now, 125 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 126 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 127 int flags, RtldLockState *lockstate); 128 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 129 RtldLockState *); 130 static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now, 131 int flags, RtldLockState *lockstate); 132 static int rtld_dirname(const char *, char *); 133 static int rtld_dirname_abs(const char *, char *); 134 static void *rtld_dlopen(const char *name, int fd, int mode); 135 static void rtld_exit(void); 136 static char *search_library_path(const char *, const char *); 137 static char *search_library_pathfds(const char *, const char *, int *); 138 static const void **get_program_var_addr(const char *, RtldLockState *); 139 static void set_program_var(const char *, const void *); 140 static int symlook_default(SymLook *, const Obj_Entry *refobj); 141 static int symlook_global(SymLook *, DoneList *); 142 static void symlook_init_from_req(SymLook *, const SymLook *); 143 static int symlook_list(SymLook *, const Objlist *, DoneList *); 144 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 145 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 146 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 147 static void trace_loaded_objects(Obj_Entry *); 148 static void unlink_object(Obj_Entry *); 149 static void unload_object(Obj_Entry *); 150 static void unref_dag(Obj_Entry *); 151 static void ref_dag(Obj_Entry *); 152 static char *origin_subst_one(char *, const char *, const char *, bool); 153 static char *origin_subst(char *, const char *); 154 static void preinit_main(void); 155 static int rtld_verify_versions(const Objlist *); 156 static int rtld_verify_object_versions(Obj_Entry *); 157 static void object_add_name(Obj_Entry *, const char *); 158 static int object_match_name(const Obj_Entry *, const char *); 159 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 160 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 161 struct dl_phdr_info *phdr_info); 162 static uint_fast32_t gnu_hash (const char *); 163 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 164 const unsigned long); 165 166 void r_debug_state(struct r_debug *, struct link_map *) __noinline; 167 void _r_debug_postinit(struct link_map *) __noinline; 168 169 /* 170 * Data declarations. 171 */ 172 static char *error_message; /* Message for dlerror(), or NULL */ 173 struct r_debug r_debug; /* for GDB; */ 174 static bool libmap_disable; /* Disable libmap */ 175 static bool ld_loadfltr; /* Immediate filters processing */ 176 static char *libmap_override; /* Maps to use in addition to libmap.conf */ 177 static bool trust; /* False for setuid and setgid programs */ 178 static bool dangerous_ld_env; /* True if environment variables have been 179 used to affect the libraries loaded */ 180 static const char *ld_bind_now; /* Environment variable for immediate binding */ 181 static const char *ld_debug; /* Environment variable for debugging */ 182 static const char *ld_library_path; /* Environment variable for search path */ 183 static const char *ld_library_dirs; /* Env variable for library descriptors */ 184 static char *ld_preload; /* Environment variable for libraries to 185 load first */ 186 static const char *ld_elf_hints_path; /* Env var. for alternative hints path */ 187 static const char *ld_tracing; /* Called from ldd to print libs */ 188 static const char *ld_utrace; /* Use utrace() to log events. */ 189 static int (*rtld_functrace)( /* Optional function call tracing hook */ 190 const char *caller_obj, 191 const char *callee_obj, 192 const char *callee_func, 193 void *stack); 194 static const Obj_Entry *rtld_functrace_obj; /* Object thereof */ 195 static Obj_Entry *obj_list; /* Head of linked list of shared objects */ 196 static Obj_Entry **obj_tail; /* Link field of last object in list */ 197 static Obj_Entry **preload_tail; 198 static Obj_Entry *obj_main; /* The main program shared object */ 199 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 200 static unsigned int obj_count; /* Number of objects in obj_list */ 201 static unsigned int obj_loads; /* Number of objects in obj_list */ 202 203 static int ld_resident; /* Non-zero if resident */ 204 static const char *ld_ary[LD_ARY_CACHE]; 205 static int ld_index; 206 static Objlist initlist; 207 208 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 209 STAILQ_HEAD_INITIALIZER(list_global); 210 static Objlist list_main = /* Objects loaded at program startup */ 211 STAILQ_HEAD_INITIALIZER(list_main); 212 static Objlist list_fini = /* Objects needing fini() calls */ 213 STAILQ_HEAD_INITIALIZER(list_fini); 214 215 static Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 216 const char *__ld_sharedlib_base; 217 218 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 219 220 extern Elf_Dyn _DYNAMIC; 221 #pragma weak _DYNAMIC 222 #ifndef RTLD_IS_DYNAMIC 223 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL) 224 #endif 225 226 #ifdef ENABLE_OSRELDATE 227 int osreldate; 228 #endif 229 230 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 231 #if 0 232 static int max_stack_flags; 233 #endif 234 235 /* 236 * Global declarations normally provided by crt1. The dynamic linker is 237 * not built with crt1, so we have to provide them ourselves. 238 */ 239 char *__progname; 240 char **environ; 241 242 /* 243 * Used to pass argc, argv to init functions. 244 */ 245 int main_argc; 246 char **main_argv; 247 248 /* 249 * Globals to control TLS allocation. 250 */ 251 size_t tls_last_offset; /* Static TLS offset of last module */ 252 size_t tls_last_size; /* Static TLS size of last module */ 253 size_t tls_static_space; /* Static TLS space allocated */ 254 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 255 int tls_max_index = 1; /* Largest module index allocated */ 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 10 278 279 struct utrace_rtld { 280 char sig[4]; /* 'RTLD' */ 281 int event; 282 void *handle; 283 void *mapbase; /* Used for 'parent' and 'init/fini' */ 284 size_t mapsize; 285 int refcnt; /* Used for 'mode' */ 286 char name[MAXPATHLEN]; 287 }; 288 289 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 290 if (ld_utrace != NULL) \ 291 ld_utrace_log(e, h, mb, ms, r, n); \ 292 } while (0) 293 294 static void 295 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 296 int refcnt, const char *name) 297 { 298 struct utrace_rtld ut; 299 300 ut.sig[0] = 'R'; 301 ut.sig[1] = 'T'; 302 ut.sig[2] = 'L'; 303 ut.sig[3] = 'D'; 304 ut.event = event; 305 ut.handle = handle; 306 ut.mapbase = mapbase; 307 ut.mapsize = mapsize; 308 ut.refcnt = refcnt; 309 bzero(ut.name, sizeof(ut.name)); 310 if (name) 311 strlcpy(ut.name, name, sizeof(ut.name)); 312 utrace(&ut, sizeof(ut)); 313 } 314 315 /* 316 * Main entry point for dynamic linking. The first argument is the 317 * stack pointer. The stack is expected to be laid out as described 318 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 319 * Specifically, the stack pointer points to a word containing 320 * ARGC. Following that in the stack is a null-terminated sequence 321 * of pointers to argument strings. Then comes a null-terminated 322 * sequence of pointers to environment strings. Finally, there is a 323 * sequence of "auxiliary vector" entries. 324 * 325 * The second argument points to a place to store the dynamic linker's 326 * exit procedure pointer and the third to a place to store the main 327 * program's object. 328 * 329 * The return value is the main program's entry point. 330 */ 331 func_ptr_type 332 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 333 { 334 Elf_Auxinfo *aux_info[AT_COUNT]; 335 int i; 336 int argc; 337 char **argv; 338 char **env; 339 Elf_Auxinfo *aux; 340 Elf_Auxinfo *auxp; 341 const char *argv0; 342 Objlist_Entry *entry; 343 Obj_Entry *obj; 344 Obj_Entry *last_interposer; 345 346 /* marino: DO NOT MOVE THESE VARIABLES TO _rtld 347 Obj_Entry **preload_tail; 348 Objlist initlist; 349 from global to here. It will break the DWARF2 unwind scheme. 350 */ 351 352 /* 353 * On entry, the dynamic linker itself has not been relocated yet. 354 * Be very careful not to reference any global data until after 355 * init_rtld has returned. It is OK to reference file-scope statics 356 * and string constants, and to call static and global functions. 357 */ 358 359 /* Find the auxiliary vector on the stack. */ 360 argc = *sp++; 361 argv = (char **) sp; 362 sp += argc + 1; /* Skip over arguments and NULL terminator */ 363 env = (char **) sp; 364 365 /* 366 * If we aren't already resident we have to dig out some more info. 367 * Note that auxinfo does not exist when we are resident. 368 * 369 * I'm not sure about the ld_resident check. It seems to read zero 370 * prior to relocation, which is what we want. When running from a 371 * resident copy everything will be relocated so we are definitely 372 * good there. 373 */ 374 if (ld_resident == 0) { 375 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 376 ; 377 aux = (Elf_Auxinfo *) sp; 378 379 /* Digest the auxiliary vector. */ 380 for (i = 0; i < AT_COUNT; i++) 381 aux_info[i] = NULL; 382 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 383 if (auxp->a_type < AT_COUNT) 384 aux_info[auxp->a_type] = auxp; 385 } 386 387 /* Initialize and relocate ourselves. */ 388 assert(aux_info[AT_BASE] != NULL); 389 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 390 } 391 392 ld_index = 0; /* don't use old env cache in case we are resident */ 393 __progname = obj_rtld.path; 394 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 395 environ = env; 396 main_argc = argc; 397 main_argv = argv; 398 399 trust = !issetugid(); 400 401 ld_bind_now = _getenv_ld("LD_BIND_NOW"); 402 /* 403 * If the process is tainted, then we un-set the dangerous environment 404 * variables. The process will be marked as tainted until setuid(2) 405 * is called. If any child process calls setuid(2) we do not want any 406 * future processes to honor the potentially un-safe variables. 407 */ 408 if (!trust) { 409 if ( unsetenv("LD_DEBUG") 410 || unsetenv("LD_PRELOAD") 411 || unsetenv("LD_LIBRARY_PATH") 412 || unsetenv("LD_LIBRARY_PATH_FDS") 413 || unsetenv("LD_ELF_HINTS_PATH") 414 || unsetenv("LD_LIBMAP") 415 || unsetenv("LD_LIBMAP_DISABLE") 416 || unsetenv("LD_LOADFLTR") 417 || unsetenv("LD_SHAREDLIB_BASE") 418 ) { 419 _rtld_error("environment corrupt; aborting"); 420 die(); 421 } 422 } 423 __ld_sharedlib_base = _getenv_ld("LD_SHAREDLIB_BASE"); 424 ld_debug = _getenv_ld("LD_DEBUG"); 425 libmap_disable = _getenv_ld("LD_LIBMAP_DISABLE") != NULL; 426 libmap_override = (char *)_getenv_ld("LD_LIBMAP"); 427 ld_library_path = _getenv_ld("LD_LIBRARY_PATH"); 428 ld_library_dirs = _getenv_ld("LD_LIBRARY_PATH_FDS"); 429 ld_preload = (char *)_getenv_ld("LD_PRELOAD"); 430 ld_elf_hints_path = _getenv_ld("LD_ELF_HINTS_PATH"); 431 ld_loadfltr = _getenv_ld("LD_LOADFLTR") != NULL; 432 dangerous_ld_env = (ld_library_path != NULL) 433 || (ld_preload != NULL) 434 || (ld_elf_hints_path != NULL) 435 || ld_loadfltr 436 || (libmap_override != NULL) 437 || libmap_disable 438 ; 439 ld_tracing = _getenv_ld("LD_TRACE_LOADED_OBJECTS"); 440 ld_utrace = _getenv_ld("LD_UTRACE"); 441 442 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 443 ld_elf_hints_path = _PATH_ELF_HINTS; 444 445 if (ld_debug != NULL && *ld_debug != '\0') 446 debug = 1; 447 dbg("%s is initialized, base address = %p", __progname, 448 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 449 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 450 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 451 452 dbg("initializing thread locks"); 453 lockdflt_init(); 454 455 /* 456 * If we are resident we can skip work that we have already done. 457 * Note that the stack is reset and there is no Elf_Auxinfo 458 * when running from a resident image, and the static globals setup 459 * between here and resident_skip will have already been setup. 460 */ 461 if (ld_resident) 462 goto resident_skip1; 463 464 /* 465 * Load the main program, or process its program header if it is 466 * already loaded. 467 */ 468 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */ 469 int fd = aux_info[AT_EXECFD]->a_un.a_val; 470 dbg("loading main program"); 471 obj_main = map_object(fd, argv0, NULL); 472 close(fd); 473 if (obj_main == NULL) 474 die(); 475 #if 0 476 max_stack_flags = obj_main->stack_flags; 477 #endif 478 } else { /* Main program already loaded. */ 479 const Elf_Phdr *phdr; 480 int phnum; 481 caddr_t entry; 482 483 dbg("processing main program's program header"); 484 assert(aux_info[AT_PHDR] != NULL); 485 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 486 assert(aux_info[AT_PHNUM] != NULL); 487 phnum = aux_info[AT_PHNUM]->a_un.a_val; 488 assert(aux_info[AT_PHENT] != NULL); 489 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 490 assert(aux_info[AT_ENTRY] != NULL); 491 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 492 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL) 493 die(); 494 } 495 496 char buf[MAXPATHLEN]; 497 if (aux_info[AT_EXECPATH] != NULL) { 498 char *kexecpath; 499 500 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 501 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 502 if (kexecpath[0] == '/') 503 obj_main->path = kexecpath; 504 else if (getcwd(buf, sizeof(buf)) == NULL || 505 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 506 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 507 obj_main->path = xstrdup(argv0); 508 else 509 obj_main->path = xstrdup(buf); 510 } else { 511 char resolved[MAXPATHLEN]; 512 dbg("No AT_EXECPATH"); 513 if (argv0[0] == '/') { 514 if (realpath(argv0, resolved) != NULL) 515 obj_main->path = xstrdup(resolved); 516 else 517 obj_main->path = xstrdup(argv0); 518 } else { 519 if (getcwd(buf, sizeof(buf)) != NULL 520 && strlcat(buf, "/", sizeof(buf)) < sizeof(buf) 521 && strlcat(buf, argv0, sizeof (buf)) < sizeof(buf) 522 && access(buf, R_OK) == 0 523 && realpath(buf, resolved) != NULL) 524 obj_main->path = xstrdup(resolved); 525 else 526 obj_main->path = xstrdup(argv0); 527 } 528 } 529 dbg("obj_main path %s", obj_main->path); 530 obj_main->mainprog = true; 531 532 if (aux_info[AT_STACKPROT] != NULL && 533 aux_info[AT_STACKPROT]->a_un.a_val != 0) 534 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 535 536 /* 537 * Get the actual dynamic linker pathname from the executable if 538 * possible. (It should always be possible.) That ensures that 539 * gdb will find the right dynamic linker even if a non-standard 540 * one is being used. 541 */ 542 if (obj_main->interp != NULL && 543 strcmp(obj_main->interp, obj_rtld.path) != 0) { 544 free(obj_rtld.path); 545 obj_rtld.path = xstrdup(obj_main->interp); 546 __progname = obj_rtld.path; 547 } 548 549 digest_dynamic(obj_main, 0); 550 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 551 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 552 obj_main->dynsymcount); 553 554 linkmap_add(obj_main); 555 linkmap_add(&obj_rtld); 556 557 /* Link the main program into the list of objects. */ 558 *obj_tail = obj_main; 559 obj_tail = &obj_main->next; 560 obj_count++; 561 obj_loads++; 562 563 /* Initialize a fake symbol for resolving undefined weak references. */ 564 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 565 sym_zero.st_shndx = SHN_UNDEF; 566 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 567 568 if (!libmap_disable) 569 libmap_disable = (bool)lm_init(libmap_override); 570 571 dbg("loading LD_PRELOAD libraries"); 572 if (load_preload_objects() == -1) 573 die(); 574 preload_tail = obj_tail; 575 576 dbg("loading needed objects"); 577 if (load_needed_objects(obj_main, 0) == -1) 578 die(); 579 580 /* Make a list of all objects loaded at startup. */ 581 last_interposer = obj_main; 582 for (obj = obj_list; obj != NULL; obj = obj->next) { 583 if (obj->z_interpose && obj != obj_main) { 584 objlist_put_after(&list_main, last_interposer, obj); 585 last_interposer = obj; 586 } else { 587 objlist_push_tail(&list_main, obj); 588 } 589 obj->refcount++; 590 } 591 592 dbg("checking for required versions"); 593 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 594 die(); 595 596 resident_skip1: 597 598 if (ld_tracing) { /* We're done */ 599 trace_loaded_objects(obj_main); 600 exit(0); 601 } 602 603 if (ld_resident) /* XXX clean this up! */ 604 goto resident_skip2; 605 606 if (_getenv_ld("LD_DUMP_REL_PRE") != NULL) { 607 dump_relocations(obj_main); 608 exit (0); 609 } 610 611 /* setup TLS for main thread */ 612 dbg("initializing initial thread local storage"); 613 STAILQ_FOREACH(entry, &list_main, link) { 614 /* 615 * Allocate all the initial objects out of the static TLS 616 * block even if they didn't ask for it. 617 */ 618 allocate_tls_offset(entry->obj); 619 } 620 621 /* 622 * Calculate the size of the TLS static segment. This is allocated 623 * for every thread. Generally make it page-aligned for efficiency, 624 * but take into account the fact that the actual allocation also 625 * includes room for the struct tls_tcb header. 626 */ 627 { 628 ssize_t space; 629 ssize_t extra; 630 631 extra = __getstatictlsextra(); 632 space = tls_last_offset + extra + sizeof(struct tls_tcb); 633 space = (space + PAGE_SIZE - 1) & ~((ssize_t)PAGE_SIZE - 1); 634 635 tls_static_space = (size_t)space - sizeof(struct tls_tcb); 636 } 637 638 /* 639 * Do not try to allocate the TLS here, let libc do it itself. 640 * (crt1 for the program will call _init_tls()) 641 */ 642 643 if (relocate_objects(obj_main, 644 ld_bind_now != NULL && *ld_bind_now != '\0', 645 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 646 die(); 647 648 dbg("doing copy relocations"); 649 if (do_copy_relocations(obj_main) == -1) 650 die(); 651 652 resident_skip2: 653 654 if (_getenv_ld("LD_RESIDENT_UNREGISTER_NOW")) { 655 if (exec_sys_unregister(-1) < 0) { 656 dbg("exec_sys_unregister failed %d\n", errno); 657 exit(errno); 658 } 659 dbg("exec_sys_unregister success\n"); 660 exit(0); 661 } 662 663 if (_getenv_ld("LD_DUMP_REL_POST") != NULL) { 664 dump_relocations(obj_main); 665 exit (0); 666 } 667 668 dbg("initializing key program variables"); 669 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 670 set_program_var("environ", env); 671 set_program_var("__elf_aux_vector", aux); 672 673 if (_getenv_ld("LD_RESIDENT_REGISTER_NOW")) { 674 extern void resident_start(void); 675 ld_resident = 1; 676 if (exec_sys_register(resident_start) < 0) { 677 dbg("exec_sys_register failed %d\n", errno); 678 exit(errno); 679 } 680 dbg("exec_sys_register success\n"); 681 exit(0); 682 } 683 684 /* Make a list of init functions to call. */ 685 objlist_init(&initlist); 686 initlist_add_objects(obj_list, preload_tail, &initlist); 687 688 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 689 690 map_stacks_exec(NULL); 691 692 dbg("resolving ifuncs"); 693 { 694 RtldLockState lockstate; 695 696 wlock_acquire(rtld_bind_lock, &lockstate); 697 if (resolve_objects_ifunc( 698 obj_main, 699 (ld_bind_now != NULL && *ld_bind_now != '\0'), 700 SYMLOOK_EARLY, 701 &lockstate) == -1) { 702 die(); 703 } 704 lock_release(rtld_bind_lock, &lockstate); 705 } 706 707 /* 708 * Do NOT call the initlist here, give libc a chance to set up 709 * the initial TLS segment. crt1 will then call _rtld_call_init(). 710 */ 711 712 dbg("transferring control to program entry point = %p", obj_main->entry); 713 714 /* Return the exit procedure and the program entry point. */ 715 *exit_proc = rtld_exit; 716 *objp = obj_main; 717 return (func_ptr_type) obj_main->entry; 718 } 719 720 /* 721 * Call the initialization list for dynamically loaded libraries. 722 * (called from crt1.c). 723 */ 724 void 725 _rtld_call_init(void) 726 { 727 RtldLockState lockstate; 728 Obj_Entry *obj; 729 730 if (!obj_main->note_present && obj_main->valid_hash_gnu) { 731 /* 732 * The use of a linker script with a PHDRS directive that does not include 733 * PT_NOTE will block the crt_no_init note. In this case we'll look for the 734 * recently added GNU hash dynamic tag which gets built by default. It is 735 * extremely unlikely to find a pre-3.1 binary without a PT_NOTE header and 736 * a gnu hash tag. If gnu hash found, consider binary to use new crt code. 737 */ 738 obj_main->crt_no_init = true; 739 dbg("Setting crt_no_init without presence of PT_NOTE header"); 740 } 741 742 wlock_acquire(rtld_bind_lock, &lockstate); 743 if (obj_main->crt_no_init) 744 preinit_main(); 745 else { 746 /* 747 * Make sure we don't call the main program's init and fini functions 748 * for binaries linked with old crt1 which calls _init itself. 749 */ 750 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 751 obj_main->init_array = obj_main->fini_array = (Elf_Addr)NULL; 752 } 753 objlist_call_init(&initlist, &lockstate); 754 _r_debug_postinit(&obj_main->linkmap); 755 objlist_clear(&initlist); 756 dbg("loading filtees"); 757 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 758 if (ld_loadfltr || obj->z_loadfltr) 759 load_filtees(obj, 0, &lockstate); 760 } 761 lock_release(rtld_bind_lock, &lockstate); 762 } 763 764 void * 765 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 766 { 767 void *ptr; 768 Elf_Addr target; 769 770 ptr = (void *)make_function_pointer(def, obj); 771 target = ((Elf_Addr (*)(void))ptr)(); 772 return ((void *)target); 773 } 774 775 Elf_Addr 776 _rtld_bind(Obj_Entry *obj, Elf_Size reloff, void *stack) 777 { 778 const Elf_Rel *rel; 779 const Elf_Sym *def; 780 const Obj_Entry *defobj; 781 Elf_Addr *where; 782 Elf_Addr target; 783 RtldLockState lockstate; 784 785 rlock_acquire(rtld_bind_lock, &lockstate); 786 if (sigsetjmp(lockstate.env, 0) != 0) 787 lock_upgrade(rtld_bind_lock, &lockstate); 788 if (obj->pltrel) 789 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 790 else 791 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 792 793 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 794 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL, 795 &lockstate); 796 if (def == NULL) 797 die(); 798 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 799 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 800 else 801 target = (Elf_Addr)(defobj->relocbase + def->st_value); 802 803 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 804 defobj->strtab + def->st_name, basename(obj->path), 805 (void *)target, basename(defobj->path)); 806 807 /* 808 * If we have a function call tracing hook, and the 809 * hook would like to keep tracing this one function, 810 * prevent the relocation so we will wind up here 811 * the next time again. 812 * 813 * We don't want to functrace calls from the functracer 814 * to avoid recursive loops. 815 */ 816 if (rtld_functrace != NULL && obj != rtld_functrace_obj) { 817 if (rtld_functrace(obj->path, 818 defobj->path, 819 defobj->strtab + def->st_name, 820 stack)) { 821 lock_release(rtld_bind_lock, &lockstate); 822 return target; 823 } 824 } 825 826 /* 827 * Write the new contents for the jmpslot. Note that depending on 828 * architecture, the value which we need to return back to the 829 * lazy binding trampoline may or may not be the target 830 * address. The value returned from reloc_jmpslot() is the value 831 * that the trampoline needs. 832 */ 833 target = reloc_jmpslot(where, target, defobj, obj, rel); 834 lock_release(rtld_bind_lock, &lockstate); 835 return target; 836 } 837 838 /* 839 * Error reporting function. Use it like printf. If formats the message 840 * into a buffer, and sets things up so that the next call to dlerror() 841 * will return the message. 842 */ 843 void 844 _rtld_error(const char *fmt, ...) 845 { 846 static char buf[512]; 847 va_list ap; 848 849 va_start(ap, fmt); 850 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 851 error_message = buf; 852 va_end(ap); 853 } 854 855 /* 856 * Return a dynamically-allocated copy of the current error message, if any. 857 */ 858 static char * 859 errmsg_save(void) 860 { 861 return error_message == NULL ? NULL : xstrdup(error_message); 862 } 863 864 /* 865 * Restore the current error message from a copy which was previously saved 866 * by errmsg_save(). The copy is freed. 867 */ 868 static void 869 errmsg_restore(char *saved_msg) 870 { 871 if (saved_msg == NULL) 872 error_message = NULL; 873 else { 874 _rtld_error("%s", saved_msg); 875 free(saved_msg); 876 } 877 } 878 879 const char * 880 basename(const char *name) 881 { 882 const char *p = strrchr(name, '/'); 883 return p != NULL ? p + 1 : name; 884 } 885 886 static struct utsname uts; 887 888 static char * 889 origin_subst_one(char *real, const char *kw, const char *subst, 890 bool may_free) 891 { 892 char *p, *p1, *res, *resp; 893 int subst_len, kw_len, subst_count, old_len, new_len; 894 895 kw_len = strlen(kw); 896 897 /* 898 * First, count the number of the keyword occurrences, to 899 * preallocate the final string. 900 */ 901 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 902 p1 = strstr(p, kw); 903 if (p1 == NULL) 904 break; 905 } 906 907 /* 908 * If the keyword is not found, just return. 909 */ 910 if (subst_count == 0) 911 return (may_free ? real : xstrdup(real)); 912 913 /* 914 * There is indeed something to substitute. Calculate the 915 * length of the resulting string, and allocate it. 916 */ 917 subst_len = strlen(subst); 918 old_len = strlen(real); 919 new_len = old_len + (subst_len - kw_len) * subst_count; 920 res = xmalloc(new_len + 1); 921 922 /* 923 * Now, execute the substitution loop. 924 */ 925 for (p = real, resp = res, *resp = '\0';;) { 926 p1 = strstr(p, kw); 927 if (p1 != NULL) { 928 /* Copy the prefix before keyword. */ 929 memcpy(resp, p, p1 - p); 930 resp += p1 - p; 931 /* Keyword replacement. */ 932 memcpy(resp, subst, subst_len); 933 resp += subst_len; 934 *resp = '\0'; 935 p = p1 + kw_len; 936 } else 937 break; 938 } 939 940 /* Copy to the end of string and finish. */ 941 strcat(resp, p); 942 if (may_free) 943 free(real); 944 return (res); 945 } 946 947 static char * 948 origin_subst(char *real, const char *origin_path) 949 { 950 char *res1, *res2, *res3, *res4; 951 952 if (uts.sysname[0] == '\0') { 953 if (uname(&uts) != 0) { 954 _rtld_error("utsname failed: %d", errno); 955 return (NULL); 956 } 957 } 958 res1 = origin_subst_one(real, "$ORIGIN", origin_path, false); 959 res2 = origin_subst_one(res1, "$OSNAME", uts.sysname, true); 960 res3 = origin_subst_one(res2, "$OSREL", uts.release, true); 961 res4 = origin_subst_one(res3, "$PLATFORM", uts.machine, true); 962 return (res4); 963 } 964 965 static void 966 die(void) 967 { 968 const char *msg = dlerror(); 969 970 if (msg == NULL) 971 msg = "Fatal error"; 972 rtld_fdputstr(STDERR_FILENO, msg); 973 rtld_fdputchar(STDERR_FILENO, '\n'); 974 _exit(1); 975 } 976 977 /* 978 * Process a shared object's DYNAMIC section, and save the important 979 * information in its Obj_Entry structure. 980 */ 981 static void 982 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 983 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 984 { 985 const Elf_Dyn *dynp; 986 Needed_Entry **needed_tail = &obj->needed; 987 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 988 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 989 const Elf_Hashelt *hashtab; 990 const Elf32_Word *hashval; 991 Elf32_Word bkt, nmaskwords; 992 int bloom_size32; 993 bool nmw_power2; 994 int plttype = DT_REL; 995 996 *dyn_rpath = NULL; 997 *dyn_soname = NULL; 998 *dyn_runpath = NULL; 999 1000 obj->bind_now = false; 1001 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 1002 switch (dynp->d_tag) { 1003 1004 case DT_REL: 1005 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 1006 break; 1007 1008 case DT_RELSZ: 1009 obj->relsize = dynp->d_un.d_val; 1010 break; 1011 1012 case DT_RELENT: 1013 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 1014 break; 1015 1016 case DT_JMPREL: 1017 obj->pltrel = (const Elf_Rel *) 1018 (obj->relocbase + dynp->d_un.d_ptr); 1019 break; 1020 1021 case DT_PLTRELSZ: 1022 obj->pltrelsize = dynp->d_un.d_val; 1023 break; 1024 1025 case DT_RELA: 1026 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 1027 break; 1028 1029 case DT_RELASZ: 1030 obj->relasize = dynp->d_un.d_val; 1031 break; 1032 1033 case DT_RELAENT: 1034 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 1035 break; 1036 1037 case DT_PLTREL: 1038 plttype = dynp->d_un.d_val; 1039 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 1040 break; 1041 1042 case DT_SYMTAB: 1043 obj->symtab = (const Elf_Sym *) 1044 (obj->relocbase + dynp->d_un.d_ptr); 1045 break; 1046 1047 case DT_SYMENT: 1048 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 1049 break; 1050 1051 case DT_STRTAB: 1052 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 1053 break; 1054 1055 case DT_STRSZ: 1056 obj->strsize = dynp->d_un.d_val; 1057 break; 1058 1059 case DT_VERNEED: 1060 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 1061 dynp->d_un.d_val); 1062 break; 1063 1064 case DT_VERNEEDNUM: 1065 obj->verneednum = dynp->d_un.d_val; 1066 break; 1067 1068 case DT_VERDEF: 1069 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 1070 dynp->d_un.d_val); 1071 break; 1072 1073 case DT_VERDEFNUM: 1074 obj->verdefnum = dynp->d_un.d_val; 1075 break; 1076 1077 case DT_VERSYM: 1078 obj->versyms = (const Elf_Versym *)(obj->relocbase + 1079 dynp->d_un.d_val); 1080 break; 1081 1082 case DT_HASH: 1083 { 1084 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1085 dynp->d_un.d_ptr); 1086 obj->nbuckets = hashtab[0]; 1087 obj->nchains = hashtab[1]; 1088 obj->buckets = hashtab + 2; 1089 obj->chains = obj->buckets + obj->nbuckets; 1090 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 1091 obj->buckets != NULL; 1092 } 1093 break; 1094 1095 case DT_GNU_HASH: 1096 { 1097 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1098 dynp->d_un.d_ptr); 1099 obj->nbuckets_gnu = hashtab[0]; 1100 obj->symndx_gnu = hashtab[1]; 1101 nmaskwords = hashtab[2]; 1102 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1103 /* Number of bitmask words is required to be power of 2 */ 1104 nmw_power2 = powerof2(nmaskwords); 1105 obj->maskwords_bm_gnu = nmaskwords - 1; 1106 obj->shift2_gnu = hashtab[3]; 1107 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4); 1108 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1109 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1110 obj->symndx_gnu; 1111 obj->valid_hash_gnu = nmw_power2 && obj->nbuckets_gnu > 0 && 1112 obj->buckets_gnu != NULL; 1113 } 1114 break; 1115 1116 case DT_NEEDED: 1117 if (!obj->rtld) { 1118 Needed_Entry *nep = NEW(Needed_Entry); 1119 nep->name = dynp->d_un.d_val; 1120 nep->obj = NULL; 1121 nep->next = NULL; 1122 1123 *needed_tail = nep; 1124 needed_tail = &nep->next; 1125 } 1126 break; 1127 1128 case DT_FILTER: 1129 if (!obj->rtld) { 1130 Needed_Entry *nep = NEW(Needed_Entry); 1131 nep->name = dynp->d_un.d_val; 1132 nep->obj = NULL; 1133 nep->next = NULL; 1134 1135 *needed_filtees_tail = nep; 1136 needed_filtees_tail = &nep->next; 1137 } 1138 break; 1139 1140 case DT_AUXILIARY: 1141 if (!obj->rtld) { 1142 Needed_Entry *nep = NEW(Needed_Entry); 1143 nep->name = dynp->d_un.d_val; 1144 nep->obj = NULL; 1145 nep->next = NULL; 1146 1147 *needed_aux_filtees_tail = nep; 1148 needed_aux_filtees_tail = &nep->next; 1149 } 1150 break; 1151 1152 case DT_PLTGOT: 1153 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 1154 break; 1155 1156 case DT_TEXTREL: 1157 obj->textrel = true; 1158 break; 1159 1160 case DT_SYMBOLIC: 1161 obj->symbolic = true; 1162 break; 1163 1164 case DT_RPATH: 1165 /* 1166 * We have to wait until later to process this, because we 1167 * might not have gotten the address of the string table yet. 1168 */ 1169 *dyn_rpath = dynp; 1170 break; 1171 1172 case DT_SONAME: 1173 *dyn_soname = dynp; 1174 break; 1175 1176 case DT_RUNPATH: 1177 *dyn_runpath = dynp; 1178 break; 1179 1180 case DT_INIT: 1181 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1182 break; 1183 1184 case DT_PREINIT_ARRAY: 1185 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1186 break; 1187 1188 case DT_PREINIT_ARRAYSZ: 1189 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1190 break; 1191 1192 case DT_INIT_ARRAY: 1193 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1194 break; 1195 1196 case DT_INIT_ARRAYSZ: 1197 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1198 break; 1199 1200 case DT_FINI: 1201 obj->fini = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1202 break; 1203 1204 case DT_FINI_ARRAY: 1205 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1206 break; 1207 1208 case DT_FINI_ARRAYSZ: 1209 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1210 break; 1211 1212 case DT_DEBUG: 1213 /* XXX - not implemented yet */ 1214 if (!early) 1215 dbg("Filling in DT_DEBUG entry"); 1216 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 1217 break; 1218 1219 case DT_FLAGS: 1220 if ((dynp->d_un.d_val & DF_ORIGIN) && trust) 1221 obj->z_origin = true; 1222 if (dynp->d_un.d_val & DF_SYMBOLIC) 1223 obj->symbolic = true; 1224 if (dynp->d_un.d_val & DF_TEXTREL) 1225 obj->textrel = true; 1226 if (dynp->d_un.d_val & DF_BIND_NOW) 1227 obj->bind_now = true; 1228 if (dynp->d_un.d_val & DF_STATIC_TLS) 1229 obj->static_tls = true; 1230 break; 1231 1232 case DT_FLAGS_1: 1233 if (dynp->d_un.d_val & DF_1_NOOPEN) 1234 obj->z_noopen = true; 1235 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust) 1236 obj->z_origin = true; 1237 /*if (dynp->d_un.d_val & DF_1_GLOBAL) 1238 XXX ;*/ 1239 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1240 obj->bind_now = true; 1241 if (dynp->d_un.d_val & DF_1_NODELETE) 1242 obj->z_nodelete = true; 1243 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1244 obj->z_loadfltr = true; 1245 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1246 obj->z_interpose = true; 1247 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1248 obj->z_nodeflib = true; 1249 break; 1250 1251 default: 1252 if (!early) { 1253 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1254 (long)dynp->d_tag); 1255 } 1256 break; 1257 } 1258 } 1259 1260 obj->traced = false; 1261 1262 if (plttype == DT_RELA) { 1263 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1264 obj->pltrel = NULL; 1265 obj->pltrelasize = obj->pltrelsize; 1266 obj->pltrelsize = 0; 1267 } 1268 1269 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1270 if (obj->valid_hash_sysv) 1271 obj->dynsymcount = obj->nchains; 1272 else if (obj->valid_hash_gnu) { 1273 obj->dynsymcount = 0; 1274 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1275 if (obj->buckets_gnu[bkt] == 0) 1276 continue; 1277 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1278 do 1279 obj->dynsymcount++; 1280 while ((*hashval++ & 1u) == 0); 1281 } 1282 obj->dynsymcount += obj->symndx_gnu; 1283 } 1284 } 1285 1286 static void 1287 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1288 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1289 { 1290 1291 if (obj->z_origin && obj->origin_path == NULL) { 1292 obj->origin_path = xmalloc(PATH_MAX); 1293 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1) 1294 die(); 1295 } 1296 1297 if (dyn_runpath != NULL) { 1298 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val; 1299 if (obj->z_origin) 1300 obj->runpath = origin_subst(obj->runpath, obj->origin_path); 1301 } 1302 else if (dyn_rpath != NULL) { 1303 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 1304 if (obj->z_origin) 1305 obj->rpath = origin_subst(obj->rpath, obj->origin_path); 1306 } 1307 1308 if (dyn_soname != NULL) 1309 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1310 } 1311 1312 static void 1313 digest_dynamic(Obj_Entry *obj, int early) 1314 { 1315 const Elf_Dyn *dyn_rpath; 1316 const Elf_Dyn *dyn_soname; 1317 const Elf_Dyn *dyn_runpath; 1318 1319 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1320 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath); 1321 } 1322 1323 /* 1324 * Process a shared object's program header. This is used only for the 1325 * main program, when the kernel has already loaded the main program 1326 * into memory before calling the dynamic linker. It creates and 1327 * returns an Obj_Entry structure. 1328 */ 1329 static Obj_Entry * 1330 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1331 { 1332 Obj_Entry *obj; 1333 const Elf_Phdr *phlimit = phdr + phnum; 1334 const Elf_Phdr *ph; 1335 Elf_Addr note_start, note_end; 1336 int nsegs = 0; 1337 1338 obj = obj_new(); 1339 for (ph = phdr; ph < phlimit; ph++) { 1340 if (ph->p_type != PT_PHDR) 1341 continue; 1342 1343 obj->phdr = phdr; 1344 obj->phsize = ph->p_memsz; 1345 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1346 break; 1347 } 1348 1349 obj->stack_flags = PF_X | PF_R | PF_W; 1350 1351 for (ph = phdr; ph < phlimit; ph++) { 1352 switch (ph->p_type) { 1353 1354 case PT_INTERP: 1355 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1356 break; 1357 1358 case PT_LOAD: 1359 if (nsegs == 0) { /* First load segment */ 1360 obj->vaddrbase = trunc_page(ph->p_vaddr); 1361 obj->mapbase = obj->vaddrbase + obj->relocbase; 1362 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1363 obj->vaddrbase; 1364 } else { /* Last load segment */ 1365 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1366 obj->vaddrbase; 1367 } 1368 nsegs++; 1369 break; 1370 1371 case PT_DYNAMIC: 1372 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1373 break; 1374 1375 case PT_TLS: 1376 obj->tlsindex = 1; 1377 obj->tlssize = ph->p_memsz; 1378 obj->tlsalign = ph->p_align; 1379 obj->tlsinitsize = ph->p_filesz; 1380 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1381 break; 1382 1383 case PT_GNU_STACK: 1384 obj->stack_flags = ph->p_flags; 1385 break; 1386 1387 case PT_GNU_RELRO: 1388 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1389 obj->relro_size = round_page(ph->p_memsz); 1390 break; 1391 1392 case PT_NOTE: 1393 obj->note_present = true; 1394 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1395 note_end = note_start + ph->p_filesz; 1396 digest_notes(obj, note_start, note_end); 1397 break; 1398 } 1399 } 1400 if (nsegs < 1) { 1401 _rtld_error("%s: too few PT_LOAD segments", path); 1402 return NULL; 1403 } 1404 1405 obj->entry = entry; 1406 return obj; 1407 } 1408 1409 void 1410 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1411 { 1412 const Elf_Note *note; 1413 const char *note_name; 1414 uintptr_t p; 1415 1416 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1417 note = (const Elf_Note *)((const char *)(note + 1) + 1418 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1419 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1420 if (note->n_namesz != sizeof(NOTE_VENDOR) || 1421 note->n_descsz != sizeof(int32_t)) 1422 continue; 1423 if (note->n_type != ABI_NOTETYPE && 1424 note->n_type != CRT_NOINIT_NOTETYPE) 1425 continue; 1426 note_name = (const char *)(note + 1); 1427 if (strncmp(NOTE_VENDOR, note_name, sizeof(NOTE_VENDOR)) != 0) 1428 continue; 1429 switch (note->n_type) { 1430 case ABI_NOTETYPE: 1431 /* DragonFly osrel note */ 1432 p = (uintptr_t)(note + 1); 1433 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1434 obj->osrel = *(const int32_t *)(p); 1435 dbg("note osrel %d", obj->osrel); 1436 break; 1437 case CRT_NOINIT_NOTETYPE: 1438 /* DragonFly 'crt does not call init' note */ 1439 obj->crt_no_init = true; 1440 dbg("note crt_no_init"); 1441 break; 1442 } 1443 } 1444 } 1445 1446 static Obj_Entry * 1447 dlcheck(void *handle) 1448 { 1449 Obj_Entry *obj; 1450 1451 for (obj = obj_list; obj != NULL; obj = obj->next) 1452 if (obj == (Obj_Entry *) handle) 1453 break; 1454 1455 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1456 _rtld_error("Invalid shared object handle %p", handle); 1457 return NULL; 1458 } 1459 return obj; 1460 } 1461 1462 /* 1463 * If the given object is already in the donelist, return true. Otherwise 1464 * add the object to the list and return false. 1465 */ 1466 static bool 1467 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1468 { 1469 unsigned int i; 1470 1471 for (i = 0; i < dlp->num_used; i++) 1472 if (dlp->objs[i] == obj) 1473 return true; 1474 /* 1475 * Our donelist allocation should always be sufficient. But if 1476 * our threads locking isn't working properly, more shared objects 1477 * could have been loaded since we allocated the list. That should 1478 * never happen, but we'll handle it properly just in case it does. 1479 */ 1480 if (dlp->num_used < dlp->num_alloc) 1481 dlp->objs[dlp->num_used++] = obj; 1482 return false; 1483 } 1484 1485 /* 1486 * Hash function for symbol table lookup. Don't even think about changing 1487 * this. It is specified by the System V ABI. 1488 */ 1489 unsigned long 1490 elf_hash(const char *name) 1491 { 1492 const unsigned char *p = (const unsigned char *) name; 1493 unsigned long h = 0; 1494 unsigned long g; 1495 1496 while (*p != '\0') { 1497 h = (h << 4) + *p++; 1498 if ((g = h & 0xf0000000) != 0) 1499 h ^= g >> 24; 1500 h &= ~g; 1501 } 1502 return h; 1503 } 1504 1505 /* 1506 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1507 * unsigned in case it's implemented with a wider type. 1508 */ 1509 static uint_fast32_t 1510 gnu_hash(const char *s) 1511 { 1512 uint_fast32_t h; 1513 unsigned char c; 1514 1515 h = 5381; 1516 for (c = *s; c != '\0'; c = *++s) 1517 h = h * 33 + c; 1518 return (h & 0xffffffff); 1519 } 1520 1521 1522 /* 1523 * Find the library with the given name, and return its full pathname. 1524 * The returned string is dynamically allocated. Generates an error 1525 * message and returns NULL if the library cannot be found. 1526 * 1527 * If the second argument is non-NULL, then it refers to an already- 1528 * loaded shared object, whose library search path will be searched. 1529 * 1530 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1531 * descriptor (which is close-on-exec) will be passed out via the third 1532 * argument. 1533 * 1534 * The search order is: 1535 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1536 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1537 * LD_LIBRARY_PATH 1538 * DT_RUNPATH in the referencing file 1539 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1540 * from list) 1541 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1542 * 1543 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1544 */ 1545 static char * 1546 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1547 { 1548 char *pathname; 1549 char *name; 1550 bool nodeflib, objgiven; 1551 1552 objgiven = refobj != NULL; 1553 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */ 1554 if (xname[0] != '/' && !trust) { 1555 _rtld_error("Absolute pathname required for shared object \"%s\"", 1556 xname); 1557 return NULL; 1558 } 1559 if (objgiven && refobj->z_origin) { 1560 return (origin_subst(__DECONST(char *, xname), 1561 refobj->origin_path)); 1562 } else { 1563 return (xstrdup(xname)); 1564 } 1565 } 1566 1567 if (libmap_disable || !objgiven || 1568 (name = lm_find(refobj->path, xname)) == NULL) 1569 name = (char *)xname; 1570 1571 dbg(" Searching for \"%s\"", name); 1572 1573 nodeflib = objgiven ? refobj->z_nodeflib : false; 1574 if ((objgiven && 1575 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1576 (objgiven && refobj->runpath == NULL && refobj != obj_main && 1577 (pathname = search_library_path(name, obj_main->rpath)) != NULL) || 1578 (pathname = search_library_path(name, ld_library_path)) != NULL || 1579 (objgiven && 1580 (pathname = search_library_path(name, refobj->runpath)) != NULL) || 1581 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL || 1582 (pathname = search_library_path(name, gethints(nodeflib))) != NULL || 1583 (objgiven && !nodeflib && 1584 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)) 1585 return (pathname); 1586 1587 if (objgiven && refobj->path != NULL) { 1588 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 1589 name, basename(refobj->path)); 1590 } else { 1591 _rtld_error("Shared object \"%s\" not found", name); 1592 } 1593 return NULL; 1594 } 1595 1596 /* 1597 * Given a symbol number in a referencing object, find the corresponding 1598 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1599 * no definition was found. Returns a pointer to the Obj_Entry of the 1600 * defining object via the reference parameter DEFOBJ_OUT. 1601 */ 1602 const Elf_Sym * 1603 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1604 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1605 RtldLockState *lockstate) 1606 { 1607 const Elf_Sym *ref; 1608 const Elf_Sym *def; 1609 const Obj_Entry *defobj; 1610 SymLook req; 1611 const char *name; 1612 int res; 1613 1614 /* 1615 * If we have already found this symbol, get the information from 1616 * the cache. 1617 */ 1618 if (symnum >= refobj->dynsymcount) 1619 return NULL; /* Bad object */ 1620 if (cache != NULL && cache[symnum].sym != NULL) { 1621 *defobj_out = cache[symnum].obj; 1622 return cache[symnum].sym; 1623 } 1624 1625 ref = refobj->symtab + symnum; 1626 name = refobj->strtab + ref->st_name; 1627 def = NULL; 1628 defobj = NULL; 1629 1630 /* 1631 * We don't have to do a full scale lookup if the symbol is local. 1632 * We know it will bind to the instance in this load module; to 1633 * which we already have a pointer (ie ref). By not doing a lookup, 1634 * we not only improve performance, but it also avoids unresolvable 1635 * symbols when local symbols are not in the hash table. 1636 * 1637 * This might occur for TLS module relocations, which simply use 1638 * symbol 0. 1639 */ 1640 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1641 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1642 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1643 symnum); 1644 } 1645 symlook_init(&req, name); 1646 req.flags = flags; 1647 req.ventry = fetch_ventry(refobj, symnum); 1648 req.lockstate = lockstate; 1649 res = symlook_default(&req, refobj); 1650 if (res == 0) { 1651 def = req.sym_out; 1652 defobj = req.defobj_out; 1653 } 1654 } else { 1655 def = ref; 1656 defobj = refobj; 1657 } 1658 1659 /* 1660 * If we found no definition and the reference is weak, treat the 1661 * symbol as having the value zero. 1662 */ 1663 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1664 def = &sym_zero; 1665 defobj = obj_main; 1666 } 1667 1668 if (def != NULL) { 1669 *defobj_out = defobj; 1670 /* Record the information in the cache to avoid subsequent lookups. */ 1671 if (cache != NULL) { 1672 cache[symnum].sym = def; 1673 cache[symnum].obj = defobj; 1674 } 1675 } else { 1676 if (refobj != &obj_rtld) 1677 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name); 1678 } 1679 return def; 1680 } 1681 1682 /* 1683 * Return the search path from the ldconfig hints file, reading it if 1684 * necessary. If nostdlib is true, then the default search paths are 1685 * not added to result. 1686 * 1687 * Returns NULL if there are problems with the hints file, 1688 * or if the search path there is empty. 1689 */ 1690 static const char * 1691 gethints(bool nostdlib) 1692 { 1693 static char *hints, *filtered_path; 1694 struct elfhints_hdr hdr; 1695 struct fill_search_info_args sargs, hargs; 1696 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1697 struct dl_serpath *SLPpath, *hintpath; 1698 char *p; 1699 unsigned int SLPndx, hintndx, fndx, fcount; 1700 int fd; 1701 size_t flen; 1702 bool skip; 1703 1704 /* First call, read the hints file */ 1705 if (hints == NULL) { 1706 /* Keep from trying again in case the hints file is bad. */ 1707 hints = ""; 1708 1709 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1710 return (NULL); 1711 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1712 hdr.magic != ELFHINTS_MAGIC || 1713 hdr.version != 1) { 1714 close(fd); 1715 return (NULL); 1716 } 1717 p = xmalloc(hdr.dirlistlen + 1); 1718 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1719 read(fd, p, hdr.dirlistlen + 1) != 1720 (ssize_t)hdr.dirlistlen + 1) { 1721 free(p); 1722 close(fd); 1723 return (NULL); 1724 } 1725 hints = p; 1726 close(fd); 1727 } 1728 1729 /* 1730 * If caller agreed to receive list which includes the default 1731 * paths, we are done. Otherwise, if we still have not 1732 * calculated filtered result, do it now. 1733 */ 1734 if (!nostdlib) 1735 return (hints[0] != '\0' ? hints : NULL); 1736 if (filtered_path != NULL) 1737 goto filt_ret; 1738 1739 /* 1740 * Obtain the list of all configured search paths, and the 1741 * list of the default paths. 1742 * 1743 * First estimate the size of the results. 1744 */ 1745 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1746 smeta.dls_cnt = 0; 1747 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1748 hmeta.dls_cnt = 0; 1749 1750 sargs.request = RTLD_DI_SERINFOSIZE; 1751 sargs.serinfo = &smeta; 1752 hargs.request = RTLD_DI_SERINFOSIZE; 1753 hargs.serinfo = &hmeta; 1754 1755 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1756 path_enumerate(p, fill_search_info, &hargs); 1757 1758 SLPinfo = xmalloc(smeta.dls_size); 1759 hintinfo = xmalloc(hmeta.dls_size); 1760 1761 /* 1762 * Next fetch both sets of paths. 1763 */ 1764 sargs.request = RTLD_DI_SERINFO; 1765 sargs.serinfo = SLPinfo; 1766 sargs.serpath = &SLPinfo->dls_serpath[0]; 1767 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1768 1769 hargs.request = RTLD_DI_SERINFO; 1770 hargs.serinfo = hintinfo; 1771 hargs.serpath = &hintinfo->dls_serpath[0]; 1772 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1773 1774 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1775 path_enumerate(p, fill_search_info, &hargs); 1776 1777 /* 1778 * Now calculate the difference between two sets, by excluding 1779 * standard paths from the full set. 1780 */ 1781 fndx = 0; 1782 fcount = 0; 1783 filtered_path = xmalloc(hdr.dirlistlen + 1); 1784 hintpath = &hintinfo->dls_serpath[0]; 1785 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1786 skip = false; 1787 SLPpath = &SLPinfo->dls_serpath[0]; 1788 /* 1789 * Check each standard path against current. 1790 */ 1791 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1792 /* matched, skip the path */ 1793 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1794 skip = true; 1795 break; 1796 } 1797 } 1798 if (skip) 1799 continue; 1800 /* 1801 * Not matched against any standard path, add the path 1802 * to result. Separate consecutive paths with ':'. 1803 */ 1804 if (fcount > 0) { 1805 filtered_path[fndx] = ':'; 1806 fndx++; 1807 } 1808 fcount++; 1809 flen = strlen(hintpath->dls_name); 1810 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1811 fndx += flen; 1812 } 1813 filtered_path[fndx] = '\0'; 1814 1815 free(SLPinfo); 1816 free(hintinfo); 1817 1818 filt_ret: 1819 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1820 } 1821 1822 static void 1823 init_dag(Obj_Entry *root) 1824 { 1825 const Needed_Entry *needed; 1826 const Objlist_Entry *elm; 1827 DoneList donelist; 1828 1829 if (root->dag_inited) 1830 return; 1831 donelist_init(&donelist); 1832 1833 /* Root object belongs to own DAG. */ 1834 objlist_push_tail(&root->dldags, root); 1835 objlist_push_tail(&root->dagmembers, root); 1836 donelist_check(&donelist, root); 1837 1838 /* 1839 * Add dependencies of root object to DAG in breadth order 1840 * by exploiting the fact that each new object get added 1841 * to the tail of the dagmembers list. 1842 */ 1843 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1844 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1845 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1846 continue; 1847 objlist_push_tail(&needed->obj->dldags, root); 1848 objlist_push_tail(&root->dagmembers, needed->obj); 1849 } 1850 } 1851 root->dag_inited = true; 1852 } 1853 1854 static void 1855 process_nodelete(Obj_Entry *root) 1856 { 1857 const Objlist_Entry *elm; 1858 1859 /* 1860 * Walk over object DAG and process every dependent object that 1861 * is marked as DF_1_NODELETE. They need to grow their own DAG, 1862 * which then should have its reference upped separately. 1863 */ 1864 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1865 if (elm->obj != NULL && elm->obj->z_nodelete && 1866 !elm->obj->ref_nodel) { 1867 dbg("obj %s nodelete", elm->obj->path); 1868 init_dag(elm->obj); 1869 ref_dag(elm->obj); 1870 elm->obj->ref_nodel = true; 1871 } 1872 } 1873 } 1874 1875 /* 1876 * Initialize the dynamic linker. The argument is the address at which 1877 * the dynamic linker has been mapped into memory. The primary task of 1878 * this function is to relocate the dynamic linker. 1879 */ 1880 static void 1881 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 1882 { 1883 Obj_Entry objtmp; /* Temporary rtld object */ 1884 const Elf_Ehdr *ehdr; 1885 const Elf_Dyn *dyn_rpath; 1886 const Elf_Dyn *dyn_soname; 1887 const Elf_Dyn *dyn_runpath; 1888 1889 /* 1890 * Conjure up an Obj_Entry structure for the dynamic linker. 1891 * 1892 * The "path" member can't be initialized yet because string constants 1893 * cannot yet be accessed. Below we will set it correctly. 1894 */ 1895 memset(&objtmp, 0, sizeof(objtmp)); 1896 objtmp.path = NULL; 1897 objtmp.rtld = true; 1898 objtmp.mapbase = mapbase; 1899 #ifdef PIC 1900 objtmp.relocbase = mapbase; 1901 #endif 1902 if (RTLD_IS_DYNAMIC()) { 1903 objtmp.dynamic = rtld_dynamic(&objtmp); 1904 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 1905 assert(objtmp.needed == NULL); 1906 assert(!objtmp.textrel); 1907 1908 /* 1909 * Temporarily put the dynamic linker entry into the object list, so 1910 * that symbols can be found. 1911 */ 1912 1913 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 1914 } 1915 ehdr = (Elf_Ehdr *)mapbase; 1916 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 1917 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 1918 1919 /* Initialize the object list. */ 1920 obj_tail = &obj_list; 1921 1922 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1923 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1924 1925 #ifdef ENABLE_OSRELDATE 1926 if (aux_info[AT_OSRELDATE] != NULL) 1927 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 1928 #endif 1929 1930 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 1931 1932 /* Replace the path with a dynamically allocated copy. */ 1933 obj_rtld.path = xstrdup(PATH_RTLD); 1934 1935 r_debug.r_brk = r_debug_state; 1936 r_debug.r_state = RT_CONSISTENT; 1937 } 1938 1939 /* 1940 * Add the init functions from a needed object list (and its recursive 1941 * needed objects) to "list". This is not used directly; it is a helper 1942 * function for initlist_add_objects(). The write lock must be held 1943 * when this function is called. 1944 */ 1945 static void 1946 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 1947 { 1948 /* Recursively process the successor needed objects. */ 1949 if (needed->next != NULL) 1950 initlist_add_neededs(needed->next, list); 1951 1952 /* Process the current needed object. */ 1953 if (needed->obj != NULL) 1954 initlist_add_objects(needed->obj, &needed->obj->next, list); 1955 } 1956 1957 /* 1958 * Scan all of the DAGs rooted in the range of objects from "obj" to 1959 * "tail" and add their init functions to "list". This recurses over 1960 * the DAGs and ensure the proper init ordering such that each object's 1961 * needed libraries are initialized before the object itself. At the 1962 * same time, this function adds the objects to the global finalization 1963 * list "list_fini" in the opposite order. The write lock must be 1964 * held when this function is called. 1965 */ 1966 static void 1967 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list) 1968 { 1969 1970 if (obj->init_scanned || obj->init_done) 1971 return; 1972 obj->init_scanned = true; 1973 1974 /* Recursively process the successor objects. */ 1975 if (&obj->next != tail) 1976 initlist_add_objects(obj->next, tail, list); 1977 1978 /* Recursively process the needed objects. */ 1979 if (obj->needed != NULL) 1980 initlist_add_neededs(obj->needed, list); 1981 if (obj->needed_filtees != NULL) 1982 initlist_add_neededs(obj->needed_filtees, list); 1983 if (obj->needed_aux_filtees != NULL) 1984 initlist_add_neededs(obj->needed_aux_filtees, list); 1985 1986 /* Add the object to the init list. */ 1987 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL || 1988 obj->init_array != (Elf_Addr)NULL) 1989 objlist_push_tail(list, obj); 1990 1991 /* Add the object to the global fini list in the reverse order. */ 1992 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 1993 && !obj->on_fini_list) { 1994 objlist_push_head(&list_fini, obj); 1995 obj->on_fini_list = true; 1996 } 1997 } 1998 1999 #ifndef FPTR_TARGET 2000 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 2001 #endif 2002 2003 static void 2004 free_needed_filtees(Needed_Entry *n) 2005 { 2006 Needed_Entry *needed, *needed1; 2007 2008 for (needed = n; needed != NULL; needed = needed->next) { 2009 if (needed->obj != NULL) { 2010 dlclose(needed->obj); 2011 needed->obj = NULL; 2012 } 2013 } 2014 for (needed = n; needed != NULL; needed = needed1) { 2015 needed1 = needed->next; 2016 free(needed); 2017 } 2018 } 2019 2020 static void 2021 unload_filtees(Obj_Entry *obj) 2022 { 2023 2024 free_needed_filtees(obj->needed_filtees); 2025 obj->needed_filtees = NULL; 2026 free_needed_filtees(obj->needed_aux_filtees); 2027 obj->needed_aux_filtees = NULL; 2028 obj->filtees_loaded = false; 2029 } 2030 2031 static void 2032 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2033 RtldLockState *lockstate) 2034 { 2035 2036 for (; needed != NULL; needed = needed->next) { 2037 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2038 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2039 RTLD_LOCAL, lockstate); 2040 } 2041 } 2042 2043 static void 2044 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2045 { 2046 2047 lock_restart_for_upgrade(lockstate); 2048 if (!obj->filtees_loaded) { 2049 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2050 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2051 obj->filtees_loaded = true; 2052 } 2053 } 2054 2055 static int 2056 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2057 { 2058 Obj_Entry *obj1; 2059 2060 for (; needed != NULL; needed = needed->next) { 2061 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2062 flags & ~RTLD_LO_NOLOAD); 2063 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2064 return (-1); 2065 } 2066 return (0); 2067 } 2068 2069 /* 2070 * Given a shared object, traverse its list of needed objects, and load 2071 * each of them. Returns 0 on success. Generates an error message and 2072 * returns -1 on failure. 2073 */ 2074 static int 2075 load_needed_objects(Obj_Entry *first, int flags) 2076 { 2077 Obj_Entry *obj; 2078 2079 for (obj = first; obj != NULL; obj = obj->next) { 2080 if (process_needed(obj, obj->needed, flags) == -1) 2081 return (-1); 2082 } 2083 return (0); 2084 } 2085 2086 static int 2087 load_preload_objects(void) 2088 { 2089 char *p = ld_preload; 2090 Obj_Entry *obj; 2091 static const char delim[] = " \t:;"; 2092 2093 if (p == NULL) 2094 return 0; 2095 2096 p += strspn(p, delim); 2097 while (*p != '\0') { 2098 size_t len = strcspn(p, delim); 2099 char savech; 2100 SymLook req; 2101 int res; 2102 2103 savech = p[len]; 2104 p[len] = '\0'; 2105 obj = load_object(p, -1, NULL, 0); 2106 if (obj == NULL) 2107 return -1; /* XXX - cleanup */ 2108 obj->z_interpose = true; 2109 p[len] = savech; 2110 p += len; 2111 p += strspn(p, delim); 2112 2113 /* Check for the magic tracing function */ 2114 symlook_init(&req, RTLD_FUNCTRACE); 2115 res = symlook_obj(&req, obj); 2116 if (res == 0) { 2117 rtld_functrace = (void *)(req.defobj_out->relocbase + 2118 req.sym_out->st_value); 2119 rtld_functrace_obj = req.defobj_out; 2120 } 2121 } 2122 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2123 return 0; 2124 } 2125 2126 static const char * 2127 printable_path(const char *path) 2128 { 2129 2130 return (path == NULL ? "<unknown>" : path); 2131 } 2132 2133 /* 2134 * Load a shared object into memory, if it is not already loaded. The 2135 * object may be specified by name or by user-supplied file descriptor 2136 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2137 * duplicate is. 2138 * 2139 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2140 * on failure. 2141 */ 2142 static Obj_Entry * 2143 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2144 { 2145 Obj_Entry *obj; 2146 int fd; 2147 struct stat sb; 2148 char *path; 2149 2150 fd = -1; 2151 if (name != NULL) { 2152 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 2153 if (object_match_name(obj, name)) 2154 return (obj); 2155 } 2156 2157 path = find_library(name, refobj, &fd); 2158 if (path == NULL) 2159 return (NULL); 2160 } else 2161 path = NULL; 2162 2163 if (fd >= 0) { 2164 /* 2165 * search_library_pathfds() opens a fresh file descriptor for the 2166 * library, so there is no need to dup(). 2167 */ 2168 } else if (fd_u == -1) { 2169 /* 2170 * If we didn't find a match by pathname, or the name is not 2171 * supplied, open the file and check again by device and inode. 2172 * This avoids false mismatches caused by multiple links or ".." 2173 * in pathnames. 2174 * 2175 * To avoid a race, we open the file and use fstat() rather than 2176 * using stat(). 2177 */ 2178 if ((fd = open(path, O_RDONLY | O_CLOEXEC)) == -1) { 2179 _rtld_error("Cannot open \"%s\"", path); 2180 free(path); 2181 return (NULL); 2182 } 2183 } else { 2184 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2185 if (fd == -1) { 2186 _rtld_error("Cannot dup fd"); 2187 free(path); 2188 return (NULL); 2189 } 2190 } 2191 if (fstat(fd, &sb) == -1) { 2192 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2193 close(fd); 2194 free(path); 2195 return NULL; 2196 } 2197 for (obj = obj_list->next; obj != NULL; obj = obj->next) 2198 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2199 break; 2200 if (obj != NULL && name != NULL) { 2201 object_add_name(obj, name); 2202 free(path); 2203 close(fd); 2204 return obj; 2205 } 2206 if (flags & RTLD_LO_NOLOAD) { 2207 free(path); 2208 close(fd); 2209 return (NULL); 2210 } 2211 2212 /* First use of this object, so we must map it in */ 2213 obj = do_load_object(fd, name, path, &sb, flags); 2214 if (obj == NULL) 2215 free(path); 2216 close(fd); 2217 2218 return obj; 2219 } 2220 2221 static Obj_Entry * 2222 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2223 int flags) 2224 { 2225 Obj_Entry *obj; 2226 struct statfs fs; 2227 2228 /* 2229 * but first, make sure that environment variables haven't been 2230 * used to circumvent the noexec flag on a filesystem. 2231 */ 2232 if (dangerous_ld_env) { 2233 if (fstatfs(fd, &fs) != 0) { 2234 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2235 return NULL; 2236 } 2237 if (fs.f_flags & MNT_NOEXEC) { 2238 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 2239 return NULL; 2240 } 2241 } 2242 dbg("loading \"%s\"", printable_path(path)); 2243 obj = map_object(fd, printable_path(path), sbp); 2244 if (obj == NULL) 2245 return NULL; 2246 2247 /* 2248 * If DT_SONAME is present in the object, digest_dynamic2 already 2249 * added it to the object names. 2250 */ 2251 if (name != NULL) 2252 object_add_name(obj, name); 2253 obj->path = path; 2254 digest_dynamic(obj, 0); 2255 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2256 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2257 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2258 RTLD_LO_DLOPEN) { 2259 dbg("refusing to load non-loadable \"%s\"", obj->path); 2260 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2261 munmap(obj->mapbase, obj->mapsize); 2262 obj_free(obj); 2263 return (NULL); 2264 } 2265 2266 *obj_tail = obj; 2267 obj_tail = &obj->next; 2268 obj_count++; 2269 obj_loads++; 2270 linkmap_add(obj); /* for GDB & dlinfo() */ 2271 #if 0 2272 max_stack_flags |= obj->stack_flags; 2273 #endif 2274 2275 dbg(" %p .. %p: %s", obj->mapbase, 2276 obj->mapbase + obj->mapsize - 1, obj->path); 2277 if (obj->textrel) 2278 dbg(" WARNING: %s has impure text", obj->path); 2279 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2280 obj->path); 2281 2282 return obj; 2283 } 2284 2285 static Obj_Entry * 2286 obj_from_addr(const void *addr) 2287 { 2288 Obj_Entry *obj; 2289 2290 for (obj = obj_list; obj != NULL; obj = obj->next) { 2291 if (addr < (void *) obj->mapbase) 2292 continue; 2293 if (addr < (void *) (obj->mapbase + obj->mapsize)) 2294 return obj; 2295 } 2296 return NULL; 2297 } 2298 2299 /* 2300 * If the main program is defined with a .preinit_array section, call 2301 * each function in order. This must occur before the initialization 2302 * of any shared object or the main program. 2303 */ 2304 static void 2305 preinit_main(void) 2306 { 2307 Elf_Addr *preinit_addr; 2308 int index; 2309 2310 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2311 if (preinit_addr == NULL) 2312 return; 2313 2314 for (index = 0; index < obj_main->preinit_array_num; index++) { 2315 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2316 dbg("calling preinit function for %s at %p", obj_main->path, 2317 (void *)preinit_addr[index]); 2318 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2319 0, 0, obj_main->path); 2320 call_init_pointer(obj_main, preinit_addr[index]); 2321 } 2322 } 2323 } 2324 2325 /* 2326 * Call the finalization functions for each of the objects in "list" 2327 * belonging to the DAG of "root" and referenced once. If NULL "root" 2328 * is specified, every finalization function will be called regardless 2329 * of the reference count and the list elements won't be freed. All of 2330 * the objects are expected to have non-NULL fini functions. 2331 */ 2332 static void 2333 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2334 { 2335 Objlist_Entry *elm; 2336 char *saved_msg; 2337 Elf_Addr *fini_addr; 2338 int index; 2339 2340 assert(root == NULL || root->refcount == 1); 2341 2342 /* 2343 * Preserve the current error message since a fini function might 2344 * call into the dynamic linker and overwrite it. 2345 */ 2346 saved_msg = errmsg_save(); 2347 do { 2348 STAILQ_FOREACH(elm, list, link) { 2349 if (root != NULL && (elm->obj->refcount != 1 || 2350 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2351 continue; 2352 2353 /* Remove object from fini list to prevent recursive invocation. */ 2354 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2355 /* 2356 * XXX: If a dlopen() call references an object while the 2357 * fini function is in progress, we might end up trying to 2358 * unload the referenced object in dlclose() or the object 2359 * won't be unloaded although its fini function has been 2360 * called. 2361 */ 2362 lock_release(rtld_bind_lock, lockstate); 2363 2364 /* 2365 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2366 * When this happens, DT_FINI_ARRAY is processed first. 2367 * It is also processed backwards. It is possible to encounter 2368 * DT_FINI_ARRAY elements with values of 0 or 1, but they need 2369 * to be ignored. 2370 */ 2371 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2372 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2373 for (index = elm->obj->fini_array_num - 1; index >= 0; index--) { 2374 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2375 dbg("calling fini array function for %s at %p", 2376 elm->obj->path, (void *)fini_addr[index]); 2377 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2378 (void *)fini_addr[index], 0, 0, elm->obj->path); 2379 call_initfini_pointer(elm->obj, fini_addr[index]); 2380 } 2381 } 2382 } 2383 if (elm->obj->fini != (Elf_Addr)NULL) { 2384 dbg("calling fini function for %s at %p", elm->obj->path, 2385 (void *)elm->obj->fini); 2386 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2387 0, 0, elm->obj->path); 2388 call_initfini_pointer(elm->obj, elm->obj->fini); 2389 } 2390 wlock_acquire(rtld_bind_lock, lockstate); 2391 /* No need to free anything if process is going down. */ 2392 if (root != NULL) 2393 free(elm); 2394 /* 2395 * We must restart the list traversal after every fini call 2396 * because a dlclose() call from the fini function or from 2397 * another thread might have modified the reference counts. 2398 */ 2399 break; 2400 } 2401 } while (elm != NULL); 2402 errmsg_restore(saved_msg); 2403 } 2404 2405 /* 2406 * Call the initialization functions for each of the objects in 2407 * "list". All of the objects are expected to have non-NULL init 2408 * functions. 2409 */ 2410 static void 2411 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2412 { 2413 Objlist_Entry *elm; 2414 Obj_Entry *obj; 2415 char *saved_msg; 2416 Elf_Addr *init_addr; 2417 int index; 2418 2419 /* 2420 * Clean init_scanned flag so that objects can be rechecked and 2421 * possibly initialized earlier if any of vectors called below 2422 * cause the change by using dlopen. 2423 */ 2424 for (obj = obj_list; obj != NULL; obj = obj->next) 2425 obj->init_scanned = false; 2426 2427 /* 2428 * Preserve the current error message since an init function might 2429 * call into the dynamic linker and overwrite it. 2430 */ 2431 saved_msg = errmsg_save(); 2432 STAILQ_FOREACH(elm, list, link) { 2433 if (elm->obj->init_done) /* Initialized early. */ 2434 continue; 2435 2436 /* 2437 * Race: other thread might try to use this object before current 2438 * one completes the initilization. Not much can be done here 2439 * without better locking. 2440 */ 2441 elm->obj->init_done = true; 2442 lock_release(rtld_bind_lock, lockstate); 2443 2444 /* 2445 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2446 * When this happens, DT_INIT is processed first. 2447 * It is possible to encounter DT_INIT_ARRAY elements with values 2448 * of 0 or 1, but they need to be ignored. 2449 */ 2450 if (elm->obj->init != (Elf_Addr)NULL) { 2451 dbg("calling init function for %s at %p", elm->obj->path, 2452 (void *)elm->obj->init); 2453 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2454 0, 0, elm->obj->path); 2455 call_initfini_pointer(elm->obj, elm->obj->init); 2456 } 2457 init_addr = (Elf_Addr *)elm->obj->init_array; 2458 if (init_addr != NULL) { 2459 for (index = 0; index < elm->obj->init_array_num; index++) { 2460 if (init_addr[index] != 0 && init_addr[index] != 1) { 2461 dbg("calling init array function for %s at %p", elm->obj->path, 2462 (void *)init_addr[index]); 2463 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2464 (void *)init_addr[index], 0, 0, elm->obj->path); 2465 call_init_pointer(elm->obj, init_addr[index]); 2466 } 2467 } 2468 } 2469 wlock_acquire(rtld_bind_lock, lockstate); 2470 } 2471 errmsg_restore(saved_msg); 2472 } 2473 2474 static void 2475 objlist_clear(Objlist *list) 2476 { 2477 Objlist_Entry *elm; 2478 2479 while (!STAILQ_EMPTY(list)) { 2480 elm = STAILQ_FIRST(list); 2481 STAILQ_REMOVE_HEAD(list, link); 2482 free(elm); 2483 } 2484 } 2485 2486 static Objlist_Entry * 2487 objlist_find(Objlist *list, const Obj_Entry *obj) 2488 { 2489 Objlist_Entry *elm; 2490 2491 STAILQ_FOREACH(elm, list, link) 2492 if (elm->obj == obj) 2493 return elm; 2494 return NULL; 2495 } 2496 2497 static void 2498 objlist_init(Objlist *list) 2499 { 2500 STAILQ_INIT(list); 2501 } 2502 2503 static void 2504 objlist_push_head(Objlist *list, Obj_Entry *obj) 2505 { 2506 Objlist_Entry *elm; 2507 2508 elm = NEW(Objlist_Entry); 2509 elm->obj = obj; 2510 STAILQ_INSERT_HEAD(list, elm, link); 2511 } 2512 2513 static void 2514 objlist_push_tail(Objlist *list, Obj_Entry *obj) 2515 { 2516 Objlist_Entry *elm; 2517 2518 elm = NEW(Objlist_Entry); 2519 elm->obj = obj; 2520 STAILQ_INSERT_TAIL(list, elm, link); 2521 } 2522 2523 static void 2524 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2525 { 2526 Objlist_Entry *elm, *listelm; 2527 2528 STAILQ_FOREACH(listelm, list, link) { 2529 if (listelm->obj == listobj) 2530 break; 2531 } 2532 elm = NEW(Objlist_Entry); 2533 elm->obj = obj; 2534 if (listelm != NULL) 2535 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2536 else 2537 STAILQ_INSERT_TAIL(list, elm, link); 2538 } 2539 2540 static void 2541 objlist_remove(Objlist *list, Obj_Entry *obj) 2542 { 2543 Objlist_Entry *elm; 2544 2545 if ((elm = objlist_find(list, obj)) != NULL) { 2546 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2547 free(elm); 2548 } 2549 } 2550 2551 /* 2552 * Relocate dag rooted in the specified object. 2553 * Returns 0 on success, or -1 on failure. 2554 */ 2555 2556 static int 2557 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2558 int flags, RtldLockState *lockstate) 2559 { 2560 Objlist_Entry *elm; 2561 int error; 2562 2563 error = 0; 2564 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2565 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2566 lockstate); 2567 if (error == -1) 2568 break; 2569 } 2570 return (error); 2571 } 2572 2573 /* 2574 * Prepare for, or clean after, relocating an object marked with 2575 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 2576 * segments are remapped read-write. After relocations are done, the 2577 * segment's permissions are returned back to the modes specified in 2578 * the phdrs. If any relocation happened, or always for wired 2579 * program, COW is triggered. 2580 */ 2581 static int 2582 reloc_textrel_prot(Obj_Entry *obj, bool before) 2583 { 2584 const Elf_Phdr *ph; 2585 void *base; 2586 size_t l, sz; 2587 int prot; 2588 2589 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 2590 l--, ph++) { 2591 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 2592 continue; 2593 base = obj->relocbase + trunc_page(ph->p_vaddr); 2594 sz = round_page(ph->p_vaddr + ph->p_filesz) - 2595 trunc_page(ph->p_vaddr); 2596 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0); 2597 /* 2598 * Make sure modified text segments are included in the 2599 * core dump since we modified it. This unfortunately causes the 2600 * entire text segment to core-out but we don't have much of a 2601 * choice. We could try to only reenable core dumps on pages 2602 * in which relocations occured but that is likely most of the text 2603 * pages anyway, and even that would not work because the rest of 2604 * the text pages would wind up as a read-only OBJT_DEFAULT object 2605 * (created due to our modifications) backed by the original OBJT_VNODE 2606 * object, and the ELF coredump code is currently only able to dump 2607 * vnode records for pure vnode-backed mappings, not vnode backings 2608 * to memory objects. 2609 */ 2610 if (before == false) 2611 madvise(base, sz, MADV_CORE); 2612 if (mprotect(base, sz, prot) == -1) { 2613 _rtld_error("%s: Cannot write-%sable text segment: %s", 2614 obj->path, before ? "en" : "dis", 2615 rtld_strerror(errno)); 2616 return (-1); 2617 } 2618 } 2619 return (0); 2620 } 2621 2622 /* 2623 * Relocate single object. 2624 * Returns 0 on success, or -1 on failure. 2625 */ 2626 static int 2627 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2628 int flags, RtldLockState *lockstate) 2629 { 2630 2631 if (obj->relocated) 2632 return (0); 2633 obj->relocated = true; 2634 if (obj != rtldobj) 2635 dbg("relocating \"%s\"", obj->path); 2636 2637 if (obj->symtab == NULL || obj->strtab == NULL || 2638 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2639 _rtld_error("%s: Shared object has no run-time symbol table", 2640 obj->path); 2641 return (-1); 2642 } 2643 2644 /* There are relocations to the write-protected text segment. */ 2645 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 2646 return (-1); 2647 2648 /* Process the non-PLT non-IFUNC relocations. */ 2649 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2650 return (-1); 2651 2652 /* Re-protected the text segment. */ 2653 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 2654 return (-1); 2655 2656 /* Set the special PLT or GOT entries. */ 2657 init_pltgot(obj); 2658 2659 /* Process the PLT relocations. */ 2660 if (reloc_plt(obj) == -1) 2661 return (-1); 2662 /* Relocate the jump slots if we are doing immediate binding. */ 2663 if (obj->bind_now || bind_now) 2664 if (reloc_jmpslots(obj, flags, lockstate) == -1) 2665 return (-1); 2666 2667 /* 2668 * Process the non-PLT IFUNC relocations. The relocations are 2669 * processed in two phases, because IFUNC resolvers may 2670 * reference other symbols, which must be readily processed 2671 * before resolvers are called. 2672 */ 2673 if (obj->non_plt_gnu_ifunc && 2674 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate)) 2675 return (-1); 2676 2677 /* 2678 * Set up the magic number and version in the Obj_Entry. These 2679 * were checked in the crt1.o from the original ElfKit, so we 2680 * set them for backward compatibility. 2681 */ 2682 obj->magic = RTLD_MAGIC; 2683 obj->version = RTLD_VERSION; 2684 2685 /* 2686 * Set relocated data to read-only status if protection specified 2687 */ 2688 2689 if (obj->relro_size) { 2690 if (mprotect(obj->relro_page, obj->relro_size, PROT_READ) == -1) { 2691 _rtld_error("%s: Cannot enforce relro relocation: %s", 2692 obj->path, rtld_strerror(errno)); 2693 return (-1); 2694 } 2695 obj->relro_protected = true; 2696 } 2697 return (0); 2698 } 2699 2700 /* 2701 * Relocate newly-loaded shared objects. The argument is a pointer to 2702 * the Obj_Entry for the first such object. All objects from the first 2703 * to the end of the list of objects are relocated. Returns 0 on success, 2704 * or -1 on failure. 2705 */ 2706 static int 2707 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2708 int flags, RtldLockState *lockstate) 2709 { 2710 Obj_Entry *obj; 2711 int error; 2712 2713 for (error = 0, obj = first; obj != NULL; obj = obj->next) { 2714 error = relocate_object(obj, bind_now, rtldobj, flags, 2715 lockstate); 2716 if (error == -1) 2717 break; 2718 } 2719 return (error); 2720 } 2721 2722 /* 2723 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2724 * referencing STT_GNU_IFUNC symbols is postponed till the other 2725 * relocations are done. The indirect functions specified as 2726 * ifunc are allowed to call other symbols, so we need to have 2727 * objects relocated before asking for resolution from indirects. 2728 * 2729 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2730 * instead of the usual lazy handling of PLT slots. It is 2731 * consistent with how GNU does it. 2732 */ 2733 static int 2734 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2735 RtldLockState *lockstate) 2736 { 2737 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2738 return (-1); 2739 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2740 reloc_gnu_ifunc(obj, flags, lockstate) == -1) 2741 return (-1); 2742 return (0); 2743 } 2744 2745 static int 2746 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags, 2747 RtldLockState *lockstate) 2748 { 2749 Obj_Entry *obj; 2750 2751 for (obj = first; obj != NULL; obj = obj->next) { 2752 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1) 2753 return (-1); 2754 } 2755 return (0); 2756 } 2757 2758 static int 2759 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2760 RtldLockState *lockstate) 2761 { 2762 Objlist_Entry *elm; 2763 2764 STAILQ_FOREACH(elm, list, link) { 2765 if (resolve_object_ifunc(elm->obj, bind_now, flags, 2766 lockstate) == -1) 2767 return (-1); 2768 } 2769 return (0); 2770 } 2771 2772 /* 2773 * Cleanup procedure. It will be called (by the atexit mechanism) just 2774 * before the process exits. 2775 */ 2776 static void 2777 rtld_exit(void) 2778 { 2779 RtldLockState lockstate; 2780 2781 wlock_acquire(rtld_bind_lock, &lockstate); 2782 dbg("rtld_exit()"); 2783 objlist_call_fini(&list_fini, NULL, &lockstate); 2784 /* No need to remove the items from the list, since we are exiting. */ 2785 if (!libmap_disable) 2786 lm_fini(); 2787 lock_release(rtld_bind_lock, &lockstate); 2788 } 2789 2790 /* 2791 * Iterate over a search path, translate each element, and invoke the 2792 * callback on the result. 2793 */ 2794 static void * 2795 path_enumerate(const char *path, path_enum_proc callback, void *arg) 2796 { 2797 const char *trans; 2798 if (path == NULL) 2799 return (NULL); 2800 2801 path += strspn(path, ":;"); 2802 while (*path != '\0') { 2803 size_t len; 2804 char *res; 2805 2806 len = strcspn(path, ":;"); 2807 trans = lm_findn(NULL, path, len); 2808 if (trans) 2809 res = callback(trans, strlen(trans), arg); 2810 else 2811 res = callback(path, len, arg); 2812 2813 if (res != NULL) 2814 return (res); 2815 2816 path += len; 2817 path += strspn(path, ":;"); 2818 } 2819 2820 return (NULL); 2821 } 2822 2823 struct try_library_args { 2824 const char *name; 2825 size_t namelen; 2826 char *buffer; 2827 size_t buflen; 2828 }; 2829 2830 static void * 2831 try_library_path(const char *dir, size_t dirlen, void *param) 2832 { 2833 struct try_library_args *arg; 2834 2835 arg = param; 2836 if (*dir == '/' || trust) { 2837 char *pathname; 2838 2839 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 2840 return (NULL); 2841 2842 pathname = arg->buffer; 2843 strncpy(pathname, dir, dirlen); 2844 pathname[dirlen] = '/'; 2845 strcpy(pathname + dirlen + 1, arg->name); 2846 2847 dbg(" Trying \"%s\"", pathname); 2848 if (access(pathname, F_OK) == 0) { /* We found it */ 2849 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 2850 strcpy(pathname, arg->buffer); 2851 return (pathname); 2852 } 2853 } 2854 return (NULL); 2855 } 2856 2857 static char * 2858 search_library_path(const char *name, const char *path) 2859 { 2860 char *p; 2861 struct try_library_args arg; 2862 2863 if (path == NULL) 2864 return NULL; 2865 2866 arg.name = name; 2867 arg.namelen = strlen(name); 2868 arg.buffer = xmalloc(PATH_MAX); 2869 arg.buflen = PATH_MAX; 2870 2871 p = path_enumerate(path, try_library_path, &arg); 2872 2873 free(arg.buffer); 2874 2875 return (p); 2876 } 2877 2878 2879 /* 2880 * Finds the library with the given name using the directory descriptors 2881 * listed in the LD_LIBRARY_PATH_FDS environment variable. 2882 * 2883 * Returns a freshly-opened close-on-exec file descriptor for the library, 2884 * or -1 if the library cannot be found. 2885 */ 2886 static char * 2887 search_library_pathfds(const char *name, const char *path, int *fdp) 2888 { 2889 char *envcopy, *fdstr, *found, *last_token; 2890 size_t len; 2891 int dirfd, fd; 2892 2893 dbg("%s('%s', '%s', fdp)", __func__, name, path); 2894 2895 /* Don't load from user-specified libdirs into setuid binaries. */ 2896 if (!trust) 2897 return (NULL); 2898 2899 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 2900 if (path == NULL) 2901 return (NULL); 2902 2903 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 2904 if (name[0] == '/') { 2905 dbg("Absolute path (%s) passed to %s", name, __func__); 2906 return (NULL); 2907 } 2908 2909 /* 2910 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 2911 * copy of the path, as strtok_r rewrites separator tokens 2912 * with '\0'. 2913 * 2914 * NOTE: strtok() uses a __thread static and cannot be used by rtld. 2915 */ 2916 found = NULL; 2917 envcopy = xstrdup(path); 2918 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 2919 fdstr = strtok_r(NULL, ":", &last_token)) { 2920 dirfd = parse_libdir(fdstr); 2921 if (dirfd < 0) 2922 break; 2923 fd = openat(dirfd, name, O_RDONLY | O_CLOEXEC); 2924 if (fd >= 0) { 2925 *fdp = fd; 2926 len = strlen(fdstr) + strlen(name) + 3; 2927 found = xmalloc(len); 2928 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 2929 _rtld_error("error generating '%d/%s'", 2930 dirfd, name); 2931 die(); 2932 } 2933 dbg("open('%s') => %d", found, fd); 2934 break; 2935 } 2936 } 2937 free(envcopy); 2938 2939 return (found); 2940 } 2941 2942 2943 int 2944 dlclose(void *handle) 2945 { 2946 Obj_Entry *root; 2947 RtldLockState lockstate; 2948 2949 wlock_acquire(rtld_bind_lock, &lockstate); 2950 root = dlcheck(handle); 2951 if (root == NULL) { 2952 lock_release(rtld_bind_lock, &lockstate); 2953 return -1; 2954 } 2955 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 2956 root->path); 2957 2958 /* Unreference the object and its dependencies. */ 2959 root->dl_refcount--; 2960 2961 if (root->refcount == 1) { 2962 /* 2963 * The object will be no longer referenced, so we must unload it. 2964 * First, call the fini functions. 2965 */ 2966 objlist_call_fini(&list_fini, root, &lockstate); 2967 2968 unref_dag(root); 2969 2970 /* Finish cleaning up the newly-unreferenced objects. */ 2971 GDB_STATE(RT_DELETE,&root->linkmap); 2972 unload_object(root); 2973 GDB_STATE(RT_CONSISTENT,NULL); 2974 } else 2975 unref_dag(root); 2976 2977 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 2978 lock_release(rtld_bind_lock, &lockstate); 2979 return 0; 2980 } 2981 2982 char * 2983 dlerror(void) 2984 { 2985 char *msg = error_message; 2986 error_message = NULL; 2987 return msg; 2988 } 2989 2990 void * 2991 dlopen(const char *name, int mode) 2992 { 2993 2994 return (rtld_dlopen(name, -1, mode)); 2995 } 2996 2997 void * 2998 fdlopen(int fd, int mode) 2999 { 3000 3001 return (rtld_dlopen(NULL, fd, mode)); 3002 } 3003 3004 static void * 3005 rtld_dlopen(const char *name, int fd, int mode) 3006 { 3007 RtldLockState lockstate; 3008 int lo_flags; 3009 3010 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3011 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3012 if (ld_tracing != NULL) { 3013 rlock_acquire(rtld_bind_lock, &lockstate); 3014 if (sigsetjmp(lockstate.env, 0) != 0) 3015 lock_upgrade(rtld_bind_lock, &lockstate); 3016 environ = (char **)*get_program_var_addr("environ", &lockstate); 3017 lock_release(rtld_bind_lock, &lockstate); 3018 } 3019 lo_flags = RTLD_LO_DLOPEN; 3020 if (mode & RTLD_NODELETE) 3021 lo_flags |= RTLD_LO_NODELETE; 3022 if (mode & RTLD_NOLOAD) 3023 lo_flags |= RTLD_LO_NOLOAD; 3024 if (ld_tracing != NULL) 3025 lo_flags |= RTLD_LO_TRACE; 3026 3027 return (dlopen_object(name, fd, obj_main, lo_flags, 3028 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3029 } 3030 3031 static void 3032 dlopen_cleanup(Obj_Entry *obj) 3033 { 3034 3035 obj->dl_refcount--; 3036 unref_dag(obj); 3037 if (obj->refcount == 0) 3038 unload_object(obj); 3039 } 3040 3041 static Obj_Entry * 3042 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3043 int mode, RtldLockState *lockstate) 3044 { 3045 Obj_Entry **old_obj_tail; 3046 Obj_Entry *obj; 3047 Objlist initlist; 3048 RtldLockState mlockstate; 3049 int result; 3050 3051 objlist_init(&initlist); 3052 3053 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3054 wlock_acquire(rtld_bind_lock, &mlockstate); 3055 lockstate = &mlockstate; 3056 } 3057 GDB_STATE(RT_ADD,NULL); 3058 3059 old_obj_tail = obj_tail; 3060 obj = NULL; 3061 if (name == NULL && fd == -1) { 3062 obj = obj_main; 3063 obj->refcount++; 3064 } else { 3065 obj = load_object(name, fd, refobj, lo_flags); 3066 } 3067 3068 if (obj) { 3069 obj->dl_refcount++; 3070 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3071 objlist_push_tail(&list_global, obj); 3072 if (*old_obj_tail != NULL) { /* We loaded something new. */ 3073 assert(*old_obj_tail == obj); 3074 if ((lo_flags & RTLD_LO_EARLY) == 0 && obj->static_tls && 3075 !allocate_tls_offset(obj)) { 3076 _rtld_error("%s: No space available " 3077 "for static TLS", 3078 obj->path); 3079 result = -1; 3080 } else { 3081 result = 0; 3082 } 3083 if (result == 0) { 3084 result = load_needed_objects( 3085 obj, 3086 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 3087 } 3088 init_dag(obj); 3089 ref_dag(obj); 3090 if (result != -1) 3091 result = rtld_verify_versions(&obj->dagmembers); 3092 if (result != -1 && ld_tracing) 3093 goto trace; 3094 if (result == -1 || relocate_object_dag(obj, 3095 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3096 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3097 lockstate) == -1) { 3098 dlopen_cleanup(obj); 3099 obj = NULL; 3100 } else if (lo_flags & RTLD_LO_EARLY) { 3101 /* 3102 * Do not call the init functions for early loaded 3103 * filtees. The image is still not initialized enough 3104 * for them to work. 3105 * 3106 * Our object is found by the global object list and 3107 * will be ordered among all init calls done right 3108 * before transferring control to main. 3109 */ 3110 } else { 3111 /* Make list of init functions to call. */ 3112 initlist_add_objects(obj, &obj->next, &initlist); 3113 } 3114 /* 3115 * Process all no_delete objects here, given them own 3116 * DAGs to prevent their dependencies from being unloaded. 3117 * This has to be done after we have loaded all of the 3118 * dependencies, so that we do not miss any. 3119 */ 3120 if (obj != NULL) 3121 process_nodelete(obj); 3122 } else { 3123 /* 3124 * Bump the reference counts for objects on this DAG. If 3125 * this is the first dlopen() call for the object that was 3126 * already loaded as a dependency, initialize the dag 3127 * starting at it. 3128 */ 3129 init_dag(obj); 3130 ref_dag(obj); 3131 3132 if ((lo_flags & RTLD_LO_TRACE) != 0) 3133 goto trace; 3134 } 3135 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3136 obj->z_nodelete) && !obj->ref_nodel) { 3137 dbg("obj %s nodelete", obj->path); 3138 ref_dag(obj); 3139 obj->z_nodelete = obj->ref_nodel = true; 3140 } 3141 } 3142 3143 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3144 name); 3145 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3146 3147 if ((lo_flags & RTLD_LO_EARLY) == 0) { 3148 map_stacks_exec(lockstate); 3149 if (obj) 3150 distribute_static_tls(&initlist, lockstate); 3151 } 3152 3153 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3154 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3155 lockstate) == -1) { 3156 objlist_clear(&initlist); 3157 dlopen_cleanup(obj); 3158 if (lockstate == &mlockstate) 3159 lock_release(rtld_bind_lock, lockstate); 3160 return (NULL); 3161 } 3162 3163 if (!(lo_flags & RTLD_LO_EARLY)) { 3164 /* Call the init functions. */ 3165 objlist_call_init(&initlist, lockstate); 3166 } 3167 objlist_clear(&initlist); 3168 if (lockstate == &mlockstate) 3169 lock_release(rtld_bind_lock, lockstate); 3170 return obj; 3171 trace: 3172 trace_loaded_objects(obj); 3173 if (lockstate == &mlockstate) 3174 lock_release(rtld_bind_lock, lockstate); 3175 exit(0); 3176 } 3177 3178 static void * 3179 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3180 int flags) 3181 { 3182 DoneList donelist; 3183 const Obj_Entry *obj, *defobj; 3184 const Elf_Sym *def; 3185 SymLook req; 3186 RtldLockState lockstate; 3187 tls_index ti; 3188 int res; 3189 3190 def = NULL; 3191 defobj = NULL; 3192 symlook_init(&req, name); 3193 req.ventry = ve; 3194 req.flags = flags | SYMLOOK_IN_PLT; 3195 req.lockstate = &lockstate; 3196 3197 rlock_acquire(rtld_bind_lock, &lockstate); 3198 if (sigsetjmp(lockstate.env, 0) != 0) 3199 lock_upgrade(rtld_bind_lock, &lockstate); 3200 if (handle == NULL || handle == RTLD_NEXT || 3201 handle == RTLD_DEFAULT || handle == RTLD_SELF || 3202 handle == RTLD_ALL) { 3203 3204 if (handle != RTLD_ALL) { 3205 if ((obj = obj_from_addr(retaddr)) == NULL) { 3206 _rtld_error("Cannot determine caller's shared object"); 3207 lock_release(rtld_bind_lock, &lockstate); 3208 return NULL; 3209 } 3210 } else { 3211 obj = obj_list; 3212 } 3213 if (handle == NULL) { /* Just the caller's shared object. */ 3214 res = symlook_obj(&req, obj); 3215 if (res == 0) { 3216 def = req.sym_out; 3217 defobj = req.defobj_out; 3218 } 3219 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3220 handle == RTLD_SELF || /* ... caller included */ 3221 handle == RTLD_ALL) { /* All Objects */ 3222 if (handle == RTLD_NEXT) 3223 obj = obj->next; 3224 for (; obj != NULL; obj = obj->next) { 3225 res = symlook_obj(&req, obj); 3226 if (res == 0) { 3227 if (def == NULL || 3228 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3229 def = req.sym_out; 3230 defobj = req.defobj_out; 3231 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3232 break; 3233 } 3234 } 3235 } 3236 /* 3237 * Search the dynamic linker itself, and possibly resolve the 3238 * symbol from there. This is how the application links to 3239 * dynamic linker services such as dlopen. 3240 */ 3241 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3242 res = symlook_obj(&req, &obj_rtld); 3243 if (res == 0) { 3244 def = req.sym_out; 3245 defobj = req.defobj_out; 3246 } 3247 } 3248 } else { 3249 assert(handle == RTLD_DEFAULT); 3250 res = symlook_default(&req, obj); 3251 if (res == 0) { 3252 defobj = req.defobj_out; 3253 def = req.sym_out; 3254 } 3255 } 3256 } else { 3257 if ((obj = dlcheck(handle)) == NULL) { 3258 lock_release(rtld_bind_lock, &lockstate); 3259 return NULL; 3260 } 3261 3262 donelist_init(&donelist); 3263 if (obj->mainprog) { 3264 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3265 res = symlook_global(&req, &donelist); 3266 if (res == 0) { 3267 def = req.sym_out; 3268 defobj = req.defobj_out; 3269 } 3270 /* 3271 * Search the dynamic linker itself, and possibly resolve the 3272 * symbol from there. This is how the application links to 3273 * dynamic linker services such as dlopen. 3274 */ 3275 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3276 res = symlook_obj(&req, &obj_rtld); 3277 if (res == 0) { 3278 def = req.sym_out; 3279 defobj = req.defobj_out; 3280 } 3281 } 3282 } 3283 else { 3284 /* Search the whole DAG rooted at the given object. */ 3285 res = symlook_list(&req, &obj->dagmembers, &donelist); 3286 if (res == 0) { 3287 def = req.sym_out; 3288 defobj = req.defobj_out; 3289 } 3290 } 3291 } 3292 3293 if (def != NULL) { 3294 lock_release(rtld_bind_lock, &lockstate); 3295 3296 /* 3297 * The value required by the caller is derived from the value 3298 * of the symbol. this is simply the relocated value of the 3299 * symbol. 3300 */ 3301 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3302 return (make_function_pointer(def, defobj)); 3303 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3304 return (rtld_resolve_ifunc(defobj, def)); 3305 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3306 ti.ti_module = defobj->tlsindex; 3307 ti.ti_offset = def->st_value; 3308 return (__tls_get_addr(&ti)); 3309 } else 3310 return (defobj->relocbase + def->st_value); 3311 } 3312 3313 _rtld_error("Undefined symbol \"%s\"", name); 3314 lock_release(rtld_bind_lock, &lockstate); 3315 return NULL; 3316 } 3317 3318 void * 3319 dlsym(void *handle, const char *name) 3320 { 3321 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3322 SYMLOOK_DLSYM); 3323 } 3324 3325 dlfunc_t 3326 dlfunc(void *handle, const char *name) 3327 { 3328 union { 3329 void *d; 3330 dlfunc_t f; 3331 } rv; 3332 3333 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3334 SYMLOOK_DLSYM); 3335 return (rv.f); 3336 } 3337 3338 void * 3339 dlvsym(void *handle, const char *name, const char *version) 3340 { 3341 Ver_Entry ventry; 3342 3343 ventry.name = version; 3344 ventry.file = NULL; 3345 ventry.hash = elf_hash(version); 3346 ventry.flags= 0; 3347 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3348 SYMLOOK_DLSYM); 3349 } 3350 3351 int 3352 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3353 { 3354 const Obj_Entry *obj; 3355 RtldLockState lockstate; 3356 3357 rlock_acquire(rtld_bind_lock, &lockstate); 3358 obj = obj_from_addr(addr); 3359 if (obj == NULL) { 3360 _rtld_error("No shared object contains address"); 3361 lock_release(rtld_bind_lock, &lockstate); 3362 return (0); 3363 } 3364 rtld_fill_dl_phdr_info(obj, phdr_info); 3365 lock_release(rtld_bind_lock, &lockstate); 3366 return (1); 3367 } 3368 3369 int 3370 dladdr(const void *addr, Dl_info *info) 3371 { 3372 const Obj_Entry *obj; 3373 const Elf_Sym *def; 3374 void *symbol_addr; 3375 unsigned long symoffset; 3376 RtldLockState lockstate; 3377 3378 rlock_acquire(rtld_bind_lock, &lockstate); 3379 obj = obj_from_addr(addr); 3380 if (obj == NULL) { 3381 _rtld_error("No shared object contains address"); 3382 lock_release(rtld_bind_lock, &lockstate); 3383 return 0; 3384 } 3385 info->dli_fname = obj->path; 3386 info->dli_fbase = obj->mapbase; 3387 info->dli_saddr = NULL; 3388 info->dli_sname = NULL; 3389 3390 /* 3391 * Walk the symbol list looking for the symbol whose address is 3392 * closest to the address sent in. 3393 */ 3394 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3395 def = obj->symtab + symoffset; 3396 3397 /* 3398 * For skip the symbol if st_shndx is either SHN_UNDEF or 3399 * SHN_COMMON. 3400 */ 3401 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3402 continue; 3403 3404 /* 3405 * If the symbol is greater than the specified address, or if it 3406 * is further away from addr than the current nearest symbol, 3407 * then reject it. 3408 */ 3409 symbol_addr = obj->relocbase + def->st_value; 3410 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3411 continue; 3412 3413 /* Update our idea of the nearest symbol. */ 3414 info->dli_sname = obj->strtab + def->st_name; 3415 info->dli_saddr = symbol_addr; 3416 3417 /* Exact match? */ 3418 if (info->dli_saddr == addr) 3419 break; 3420 } 3421 lock_release(rtld_bind_lock, &lockstate); 3422 return 1; 3423 } 3424 3425 int 3426 dlinfo(void *handle, int request, void *p) 3427 { 3428 const Obj_Entry *obj; 3429 RtldLockState lockstate; 3430 int error; 3431 3432 rlock_acquire(rtld_bind_lock, &lockstate); 3433 3434 if (handle == NULL || handle == RTLD_SELF) { 3435 void *retaddr; 3436 3437 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3438 if ((obj = obj_from_addr(retaddr)) == NULL) 3439 _rtld_error("Cannot determine caller's shared object"); 3440 } else 3441 obj = dlcheck(handle); 3442 3443 if (obj == NULL) { 3444 lock_release(rtld_bind_lock, &lockstate); 3445 return (-1); 3446 } 3447 3448 error = 0; 3449 switch (request) { 3450 case RTLD_DI_LINKMAP: 3451 *((struct link_map const **)p) = &obj->linkmap; 3452 break; 3453 case RTLD_DI_ORIGIN: 3454 error = rtld_dirname(obj->path, p); 3455 break; 3456 3457 case RTLD_DI_SERINFOSIZE: 3458 case RTLD_DI_SERINFO: 3459 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3460 break; 3461 3462 default: 3463 _rtld_error("Invalid request %d passed to dlinfo()", request); 3464 error = -1; 3465 } 3466 3467 lock_release(rtld_bind_lock, &lockstate); 3468 3469 return (error); 3470 } 3471 3472 static void 3473 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3474 { 3475 3476 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3477 phdr_info->dlpi_name = obj->path; 3478 phdr_info->dlpi_phdr = obj->phdr; 3479 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3480 phdr_info->dlpi_tls_modid = obj->tlsindex; 3481 phdr_info->dlpi_tls_data = obj->tlsinit; 3482 phdr_info->dlpi_adds = obj_loads; 3483 phdr_info->dlpi_subs = obj_loads - obj_count; 3484 } 3485 3486 int 3487 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3488 { 3489 struct dl_phdr_info phdr_info; 3490 const Obj_Entry *obj; 3491 RtldLockState bind_lockstate, phdr_lockstate; 3492 int error; 3493 3494 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3495 rlock_acquire(rtld_bind_lock, &bind_lockstate); 3496 3497 error = 0; 3498 3499 for (obj = obj_list; obj != NULL; obj = obj->next) { 3500 rtld_fill_dl_phdr_info(obj, &phdr_info); 3501 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0) 3502 break; 3503 3504 } 3505 if (error == 0) { 3506 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3507 error = callback(&phdr_info, sizeof(phdr_info), param); 3508 } 3509 3510 lock_release(rtld_bind_lock, &bind_lockstate); 3511 lock_release(rtld_phdr_lock, &phdr_lockstate); 3512 3513 return (error); 3514 } 3515 3516 static void * 3517 fill_search_info(const char *dir, size_t dirlen, void *param) 3518 { 3519 struct fill_search_info_args *arg; 3520 3521 arg = param; 3522 3523 if (arg->request == RTLD_DI_SERINFOSIZE) { 3524 arg->serinfo->dls_cnt ++; 3525 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3526 } else { 3527 struct dl_serpath *s_entry; 3528 3529 s_entry = arg->serpath; 3530 s_entry->dls_name = arg->strspace; 3531 s_entry->dls_flags = arg->flags; 3532 3533 strncpy(arg->strspace, dir, dirlen); 3534 arg->strspace[dirlen] = '\0'; 3535 3536 arg->strspace += dirlen + 1; 3537 arg->serpath++; 3538 } 3539 3540 return (NULL); 3541 } 3542 3543 static int 3544 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3545 { 3546 struct dl_serinfo _info; 3547 struct fill_search_info_args args; 3548 3549 args.request = RTLD_DI_SERINFOSIZE; 3550 args.serinfo = &_info; 3551 3552 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3553 _info.dls_cnt = 0; 3554 3555 path_enumerate(obj->rpath, fill_search_info, &args); 3556 path_enumerate(ld_library_path, fill_search_info, &args); 3557 path_enumerate(obj->runpath, fill_search_info, &args); 3558 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args); 3559 if (!obj->z_nodeflib) 3560 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 3561 3562 3563 if (request == RTLD_DI_SERINFOSIZE) { 3564 info->dls_size = _info.dls_size; 3565 info->dls_cnt = _info.dls_cnt; 3566 return (0); 3567 } 3568 3569 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3570 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3571 return (-1); 3572 } 3573 3574 args.request = RTLD_DI_SERINFO; 3575 args.serinfo = info; 3576 args.serpath = &info->dls_serpath[0]; 3577 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3578 3579 args.flags = LA_SER_RUNPATH; 3580 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 3581 return (-1); 3582 3583 args.flags = LA_SER_LIBPATH; 3584 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 3585 return (-1); 3586 3587 args.flags = LA_SER_RUNPATH; 3588 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL) 3589 return (-1); 3590 3591 args.flags = LA_SER_CONFIG; 3592 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args) 3593 != NULL) 3594 return (-1); 3595 3596 args.flags = LA_SER_DEFAULT; 3597 if (!obj->z_nodeflib && 3598 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 3599 return (-1); 3600 return (0); 3601 } 3602 3603 static int 3604 rtld_dirname(const char *path, char *bname) 3605 { 3606 const char *endp; 3607 3608 /* Empty or NULL string gets treated as "." */ 3609 if (path == NULL || *path == '\0') { 3610 bname[0] = '.'; 3611 bname[1] = '\0'; 3612 return (0); 3613 } 3614 3615 /* Strip trailing slashes */ 3616 endp = path + strlen(path) - 1; 3617 while (endp > path && *endp == '/') 3618 endp--; 3619 3620 /* Find the start of the dir */ 3621 while (endp > path && *endp != '/') 3622 endp--; 3623 3624 /* Either the dir is "/" or there are no slashes */ 3625 if (endp == path) { 3626 bname[0] = *endp == '/' ? '/' : '.'; 3627 bname[1] = '\0'; 3628 return (0); 3629 } else { 3630 do { 3631 endp--; 3632 } while (endp > path && *endp == '/'); 3633 } 3634 3635 if (endp - path + 2 > PATH_MAX) 3636 { 3637 _rtld_error("Filename is too long: %s", path); 3638 return(-1); 3639 } 3640 3641 strncpy(bname, path, endp - path + 1); 3642 bname[endp - path + 1] = '\0'; 3643 return (0); 3644 } 3645 3646 static int 3647 rtld_dirname_abs(const char *path, char *base) 3648 { 3649 char base_rel[PATH_MAX]; 3650 3651 if (rtld_dirname(path, base) == -1) 3652 return (-1); 3653 if (base[0] == '/') 3654 return (0); 3655 if (getcwd(base_rel, sizeof(base_rel)) == NULL || 3656 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) || 3657 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel)) 3658 return (-1); 3659 strcpy(base, base_rel); 3660 return (0); 3661 } 3662 3663 static void 3664 linkmap_add(Obj_Entry *obj) 3665 { 3666 struct link_map *l = &obj->linkmap; 3667 struct link_map *prev; 3668 3669 obj->linkmap.l_name = obj->path; 3670 obj->linkmap.l_addr = obj->mapbase; 3671 obj->linkmap.l_ld = obj->dynamic; 3672 3673 if (r_debug.r_map == NULL) { 3674 r_debug.r_map = l; 3675 return; 3676 } 3677 3678 /* 3679 * Scan to the end of the list, but not past the entry for the 3680 * dynamic linker, which we want to keep at the very end. 3681 */ 3682 for (prev = r_debug.r_map; 3683 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3684 prev = prev->l_next) 3685 ; 3686 3687 /* Link in the new entry. */ 3688 l->l_prev = prev; 3689 l->l_next = prev->l_next; 3690 if (l->l_next != NULL) 3691 l->l_next->l_prev = l; 3692 prev->l_next = l; 3693 } 3694 3695 static void 3696 linkmap_delete(Obj_Entry *obj) 3697 { 3698 struct link_map *l = &obj->linkmap; 3699 3700 if (l->l_prev == NULL) { 3701 if ((r_debug.r_map = l->l_next) != NULL) 3702 l->l_next->l_prev = NULL; 3703 return; 3704 } 3705 3706 if ((l->l_prev->l_next = l->l_next) != NULL) 3707 l->l_next->l_prev = l->l_prev; 3708 } 3709 3710 /* 3711 * Function for the debugger to set a breakpoint on to gain control. 3712 * 3713 * The two parameters allow the debugger to easily find and determine 3714 * what the runtime loader is doing and to whom it is doing it. 3715 * 3716 * When the loadhook trap is hit (r_debug_state, set at program 3717 * initialization), the arguments can be found on the stack: 3718 * 3719 * +8 struct link_map *m 3720 * +4 struct r_debug *rd 3721 * +0 RetAddr 3722 */ 3723 void 3724 r_debug_state(struct r_debug* rd, struct link_map *m) 3725 { 3726 /* 3727 * The following is a hack to force the compiler to emit calls to 3728 * this function, even when optimizing. If the function is empty, 3729 * the compiler is not obliged to emit any code for calls to it, 3730 * even when marked __noinline. However, gdb depends on those 3731 * calls being made. 3732 */ 3733 __asm __volatile("" : : : "memory"); 3734 } 3735 3736 /* 3737 * A function called after init routines have completed. This can be used to 3738 * break before a program's entry routine is called, and can be used when 3739 * main is not available in the symbol table. 3740 */ 3741 void 3742 _r_debug_postinit(struct link_map *m) 3743 { 3744 3745 /* See r_debug_state(). */ 3746 __asm __volatile("" : : : "memory"); 3747 } 3748 3749 /* 3750 * Get address of the pointer variable in the main program. 3751 * Prefer non-weak symbol over the weak one. 3752 */ 3753 static const void ** 3754 get_program_var_addr(const char *name, RtldLockState *lockstate) 3755 { 3756 SymLook req; 3757 DoneList donelist; 3758 3759 symlook_init(&req, name); 3760 req.lockstate = lockstate; 3761 donelist_init(&donelist); 3762 if (symlook_global(&req, &donelist) != 0) 3763 return (NULL); 3764 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 3765 return ((const void **)make_function_pointer(req.sym_out, 3766 req.defobj_out)); 3767 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 3768 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 3769 else 3770 return ((const void **)(req.defobj_out->relocbase + 3771 req.sym_out->st_value)); 3772 } 3773 3774 /* 3775 * Set a pointer variable in the main program to the given value. This 3776 * is used to set key variables such as "environ" before any of the 3777 * init functions are called. 3778 */ 3779 static void 3780 set_program_var(const char *name, const void *value) 3781 { 3782 const void **addr; 3783 3784 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 3785 dbg("\"%s\": *%p <-- %p", name, addr, value); 3786 *addr = value; 3787 } 3788 } 3789 3790 /* 3791 * Search the global objects, including dependencies and main object, 3792 * for the given symbol. 3793 */ 3794 static int 3795 symlook_global(SymLook *req, DoneList *donelist) 3796 { 3797 SymLook req1; 3798 const Objlist_Entry *elm; 3799 int res; 3800 3801 symlook_init_from_req(&req1, req); 3802 3803 /* Search all objects loaded at program start up. */ 3804 if (req->defobj_out == NULL || 3805 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3806 res = symlook_list(&req1, &list_main, donelist); 3807 if (res == 0 && (req->defobj_out == NULL || 3808 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3809 req->sym_out = req1.sym_out; 3810 req->defobj_out = req1.defobj_out; 3811 assert(req->defobj_out != NULL); 3812 } 3813 } 3814 3815 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 3816 STAILQ_FOREACH(elm, &list_global, link) { 3817 if (req->defobj_out != NULL && 3818 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3819 break; 3820 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 3821 if (res == 0 && (req->defobj_out == NULL || 3822 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3823 req->sym_out = req1.sym_out; 3824 req->defobj_out = req1.defobj_out; 3825 assert(req->defobj_out != NULL); 3826 } 3827 } 3828 3829 return (req->sym_out != NULL ? 0 : ESRCH); 3830 } 3831 3832 /* 3833 * This is a special version of getenv which is far more efficient 3834 * at finding LD_ environment vars. 3835 */ 3836 static 3837 const char * 3838 _getenv_ld(const char *id) 3839 { 3840 const char *envp; 3841 int i, j; 3842 int idlen = strlen(id); 3843 3844 if (ld_index == LD_ARY_CACHE) 3845 return(getenv(id)); 3846 if (ld_index == 0) { 3847 for (i = j = 0; (envp = environ[i]) != NULL && j < LD_ARY_CACHE; ++i) { 3848 if (envp[0] == 'L' && envp[1] == 'D' && envp[2] == '_') 3849 ld_ary[j++] = envp; 3850 } 3851 if (j == 0) 3852 ld_ary[j++] = ""; 3853 ld_index = j; 3854 } 3855 for (i = ld_index - 1; i >= 0; --i) { 3856 if (strncmp(ld_ary[i], id, idlen) == 0 && ld_ary[i][idlen] == '=') 3857 return(ld_ary[i] + idlen + 1); 3858 } 3859 return(NULL); 3860 } 3861 3862 /* 3863 * Given a symbol name in a referencing object, find the corresponding 3864 * definition of the symbol. Returns a pointer to the symbol, or NULL if 3865 * no definition was found. Returns a pointer to the Obj_Entry of the 3866 * defining object via the reference parameter DEFOBJ_OUT. 3867 */ 3868 static int 3869 symlook_default(SymLook *req, const Obj_Entry *refobj) 3870 { 3871 DoneList donelist; 3872 const Objlist_Entry *elm; 3873 SymLook req1; 3874 int res; 3875 3876 donelist_init(&donelist); 3877 symlook_init_from_req(&req1, req); 3878 3879 /* Look first in the referencing object if linked symbolically. */ 3880 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 3881 res = symlook_obj(&req1, refobj); 3882 if (res == 0) { 3883 req->sym_out = req1.sym_out; 3884 req->defobj_out = req1.defobj_out; 3885 assert(req->defobj_out != NULL); 3886 } 3887 } 3888 3889 symlook_global(req, &donelist); 3890 3891 /* Search all dlopened DAGs containing the referencing object. */ 3892 STAILQ_FOREACH(elm, &refobj->dldags, link) { 3893 if (req->sym_out != NULL && 3894 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3895 break; 3896 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 3897 if (res == 0 && (req->sym_out == NULL || 3898 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3899 req->sym_out = req1.sym_out; 3900 req->defobj_out = req1.defobj_out; 3901 assert(req->defobj_out != NULL); 3902 } 3903 } 3904 3905 /* 3906 * Search the dynamic linker itself, and possibly resolve the 3907 * symbol from there. This is how the application links to 3908 * dynamic linker services such as dlopen. 3909 */ 3910 if (req->sym_out == NULL || 3911 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3912 res = symlook_obj(&req1, &obj_rtld); 3913 if (res == 0) { 3914 req->sym_out = req1.sym_out; 3915 req->defobj_out = req1.defobj_out; 3916 assert(req->defobj_out != NULL); 3917 } 3918 } 3919 3920 return (req->sym_out != NULL ? 0 : ESRCH); 3921 } 3922 3923 static int 3924 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 3925 { 3926 const Elf_Sym *def; 3927 const Obj_Entry *defobj; 3928 const Objlist_Entry *elm; 3929 SymLook req1; 3930 int res; 3931 3932 def = NULL; 3933 defobj = NULL; 3934 STAILQ_FOREACH(elm, objlist, link) { 3935 if (donelist_check(dlp, elm->obj)) 3936 continue; 3937 symlook_init_from_req(&req1, req); 3938 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 3939 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3940 def = req1.sym_out; 3941 defobj = req1.defobj_out; 3942 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3943 break; 3944 } 3945 } 3946 } 3947 if (def != NULL) { 3948 req->sym_out = def; 3949 req->defobj_out = defobj; 3950 return (0); 3951 } 3952 return (ESRCH); 3953 } 3954 3955 /* 3956 * Search the chain of DAGS cointed to by the given Needed_Entry 3957 * for a symbol of the given name. Each DAG is scanned completely 3958 * before advancing to the next one. Returns a pointer to the symbol, 3959 * or NULL if no definition was found. 3960 */ 3961 static int 3962 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 3963 { 3964 const Elf_Sym *def; 3965 const Needed_Entry *n; 3966 const Obj_Entry *defobj; 3967 SymLook req1; 3968 int res; 3969 3970 def = NULL; 3971 defobj = NULL; 3972 symlook_init_from_req(&req1, req); 3973 for (n = needed; n != NULL; n = n->next) { 3974 if (n->obj == NULL || 3975 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 3976 continue; 3977 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3978 def = req1.sym_out; 3979 defobj = req1.defobj_out; 3980 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3981 break; 3982 } 3983 } 3984 if (def != NULL) { 3985 req->sym_out = def; 3986 req->defobj_out = defobj; 3987 return (0); 3988 } 3989 return (ESRCH); 3990 } 3991 3992 /* 3993 * Search the symbol table of a single shared object for a symbol of 3994 * the given name and version, if requested. Returns a pointer to the 3995 * symbol, or NULL if no definition was found. If the object is 3996 * filter, return filtered symbol from filtee. 3997 * 3998 * The symbol's hash value is passed in for efficiency reasons; that 3999 * eliminates many recomputations of the hash value. 4000 */ 4001 int 4002 symlook_obj(SymLook *req, const Obj_Entry *obj) 4003 { 4004 DoneList donelist; 4005 SymLook req1; 4006 int flags, res, mres; 4007 4008 /* 4009 * If there is at least one valid hash at this point, we prefer to 4010 * use the faster GNU version if available. 4011 */ 4012 if (obj->valid_hash_gnu) 4013 mres = symlook_obj1_gnu(req, obj); 4014 else if (obj->valid_hash_sysv) 4015 mres = symlook_obj1_sysv(req, obj); 4016 else 4017 return (EINVAL); 4018 4019 if (mres == 0) { 4020 if (obj->needed_filtees != NULL) { 4021 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4022 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4023 donelist_init(&donelist); 4024 symlook_init_from_req(&req1, req); 4025 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 4026 if (res == 0) { 4027 req->sym_out = req1.sym_out; 4028 req->defobj_out = req1.defobj_out; 4029 } 4030 return (res); 4031 } 4032 if (obj->needed_aux_filtees != NULL) { 4033 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4034 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4035 donelist_init(&donelist); 4036 symlook_init_from_req(&req1, req); 4037 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 4038 if (res == 0) { 4039 req->sym_out = req1.sym_out; 4040 req->defobj_out = req1.defobj_out; 4041 return (res); 4042 } 4043 } 4044 } 4045 return (mres); 4046 } 4047 4048 /* Symbol match routine common to both hash functions */ 4049 static bool 4050 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4051 const unsigned long symnum) 4052 { 4053 Elf_Versym verndx; 4054 const Elf_Sym *symp; 4055 const char *strp; 4056 4057 symp = obj->symtab + symnum; 4058 strp = obj->strtab + symp->st_name; 4059 4060 switch (ELF_ST_TYPE(symp->st_info)) { 4061 case STT_FUNC: 4062 case STT_NOTYPE: 4063 case STT_OBJECT: 4064 case STT_COMMON: 4065 case STT_GNU_IFUNC: 4066 if (symp->st_value == 0) 4067 return (false); 4068 /* fallthrough */ 4069 case STT_TLS: 4070 if (symp->st_shndx != SHN_UNDEF) 4071 break; 4072 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4073 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4074 break; 4075 /* fallthrough */ 4076 default: 4077 return (false); 4078 } 4079 if (strcmp(req->name, strp) != 0) 4080 return (false); 4081 4082 if (req->ventry == NULL) { 4083 if (obj->versyms != NULL) { 4084 verndx = VER_NDX(obj->versyms[symnum]); 4085 if (verndx > obj->vernum) { 4086 _rtld_error( 4087 "%s: symbol %s references wrong version %d", 4088 obj->path, obj->strtab + symnum, verndx); 4089 return (false); 4090 } 4091 /* 4092 * If we are not called from dlsym (i.e. this 4093 * is a normal relocation from unversioned 4094 * binary), accept the symbol immediately if 4095 * it happens to have first version after this 4096 * shared object became versioned. Otherwise, 4097 * if symbol is versioned and not hidden, 4098 * remember it. If it is the only symbol with 4099 * this name exported by the shared object, it 4100 * will be returned as a match by the calling 4101 * function. If symbol is global (verndx < 2) 4102 * accept it unconditionally. 4103 */ 4104 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4105 verndx == VER_NDX_GIVEN) { 4106 result->sym_out = symp; 4107 return (true); 4108 } 4109 else if (verndx >= VER_NDX_GIVEN) { 4110 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4111 == 0) { 4112 if (result->vsymp == NULL) 4113 result->vsymp = symp; 4114 result->vcount++; 4115 } 4116 return (false); 4117 } 4118 } 4119 result->sym_out = symp; 4120 return (true); 4121 } 4122 if (obj->versyms == NULL) { 4123 if (object_match_name(obj, req->ventry->name)) { 4124 _rtld_error("%s: object %s should provide version %s " 4125 "for symbol %s", obj_rtld.path, obj->path, 4126 req->ventry->name, obj->strtab + symnum); 4127 return (false); 4128 } 4129 } else { 4130 verndx = VER_NDX(obj->versyms[symnum]); 4131 if (verndx > obj->vernum) { 4132 _rtld_error("%s: symbol %s references wrong version %d", 4133 obj->path, obj->strtab + symnum, verndx); 4134 return (false); 4135 } 4136 if (obj->vertab[verndx].hash != req->ventry->hash || 4137 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4138 /* 4139 * Version does not match. Look if this is a 4140 * global symbol and if it is not hidden. If 4141 * global symbol (verndx < 2) is available, 4142 * use it. Do not return symbol if we are 4143 * called by dlvsym, because dlvsym looks for 4144 * a specific version and default one is not 4145 * what dlvsym wants. 4146 */ 4147 if ((req->flags & SYMLOOK_DLSYM) || 4148 (verndx >= VER_NDX_GIVEN) || 4149 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4150 return (false); 4151 } 4152 } 4153 result->sym_out = symp; 4154 return (true); 4155 } 4156 4157 /* 4158 * Search for symbol using SysV hash function. 4159 * obj->buckets is known not to be NULL at this point; the test for this was 4160 * performed with the obj->valid_hash_sysv assignment. 4161 */ 4162 static int 4163 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4164 { 4165 unsigned long symnum; 4166 Sym_Match_Result matchres; 4167 4168 matchres.sym_out = NULL; 4169 matchres.vsymp = NULL; 4170 matchres.vcount = 0; 4171 4172 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4173 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4174 if (symnum >= obj->nchains) 4175 return (ESRCH); /* Bad object */ 4176 4177 if (matched_symbol(req, obj, &matchres, symnum)) { 4178 req->sym_out = matchres.sym_out; 4179 req->defobj_out = obj; 4180 return (0); 4181 } 4182 } 4183 if (matchres.vcount == 1) { 4184 req->sym_out = matchres.vsymp; 4185 req->defobj_out = obj; 4186 return (0); 4187 } 4188 return (ESRCH); 4189 } 4190 4191 /* Search for symbol using GNU hash function */ 4192 static int 4193 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4194 { 4195 Elf_Addr bloom_word; 4196 const Elf32_Word *hashval; 4197 Elf32_Word bucket; 4198 Sym_Match_Result matchres; 4199 unsigned int h1, h2; 4200 unsigned long symnum; 4201 4202 matchres.sym_out = NULL; 4203 matchres.vsymp = NULL; 4204 matchres.vcount = 0; 4205 4206 /* Pick right bitmask word from Bloom filter array */ 4207 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4208 obj->maskwords_bm_gnu]; 4209 4210 /* Calculate modulus word size of gnu hash and its derivative */ 4211 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4212 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4213 4214 /* Filter out the "definitely not in set" queries */ 4215 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4216 return (ESRCH); 4217 4218 /* Locate hash chain and corresponding value element*/ 4219 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4220 if (bucket == 0) 4221 return (ESRCH); 4222 hashval = &obj->chain_zero_gnu[bucket]; 4223 do { 4224 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4225 symnum = hashval - obj->chain_zero_gnu; 4226 if (matched_symbol(req, obj, &matchres, symnum)) { 4227 req->sym_out = matchres.sym_out; 4228 req->defobj_out = obj; 4229 return (0); 4230 } 4231 } 4232 } while ((*hashval++ & 1) == 0); 4233 if (matchres.vcount == 1) { 4234 req->sym_out = matchres.vsymp; 4235 req->defobj_out = obj; 4236 return (0); 4237 } 4238 return (ESRCH); 4239 } 4240 4241 static void 4242 trace_loaded_objects(Obj_Entry *obj) 4243 { 4244 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4245 int c; 4246 4247 if ((main_local = _getenv_ld("LD_TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 4248 main_local = ""; 4249 4250 if ((fmt1 = _getenv_ld("LD_TRACE_LOADED_OBJECTS_FMT1")) == NULL) 4251 fmt1 = "\t%o => %p (%x)\n"; 4252 4253 if ((fmt2 = _getenv_ld("LD_TRACE_LOADED_OBJECTS_FMT2")) == NULL) 4254 fmt2 = "\t%o (%x)\n"; 4255 4256 list_containers = _getenv_ld("LD_TRACE_LOADED_OBJECTS_ALL"); 4257 4258 for (; obj; obj = obj->next) { 4259 Needed_Entry *needed; 4260 char *name, *path; 4261 bool is_lib; 4262 4263 if (list_containers && obj->needed != NULL) 4264 rtld_printf("%s:\n", obj->path); 4265 for (needed = obj->needed; needed; needed = needed->next) { 4266 if (needed->obj != NULL) { 4267 if (needed->obj->traced && !list_containers) 4268 continue; 4269 needed->obj->traced = true; 4270 path = needed->obj->path; 4271 } else 4272 path = "not found"; 4273 4274 name = (char *)obj->strtab + needed->name; 4275 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4276 4277 fmt = is_lib ? fmt1 : fmt2; 4278 while ((c = *fmt++) != '\0') { 4279 switch (c) { 4280 default: 4281 rtld_putchar(c); 4282 continue; 4283 case '\\': 4284 switch (c = *fmt) { 4285 case '\0': 4286 continue; 4287 case 'n': 4288 rtld_putchar('\n'); 4289 break; 4290 case 't': 4291 rtld_putchar('\t'); 4292 break; 4293 } 4294 break; 4295 case '%': 4296 switch (c = *fmt) { 4297 case '\0': 4298 continue; 4299 case '%': 4300 default: 4301 rtld_putchar(c); 4302 break; 4303 case 'A': 4304 rtld_putstr(main_local); 4305 break; 4306 case 'a': 4307 rtld_putstr(obj_main->path); 4308 break; 4309 case 'o': 4310 rtld_putstr(name); 4311 break; 4312 case 'p': 4313 rtld_putstr(path); 4314 break; 4315 case 'x': 4316 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4317 0); 4318 break; 4319 } 4320 break; 4321 } 4322 ++fmt; 4323 } 4324 } 4325 } 4326 } 4327 4328 /* 4329 * Unload a dlopened object and its dependencies from memory and from 4330 * our data structures. It is assumed that the DAG rooted in the 4331 * object has already been unreferenced, and that the object has a 4332 * reference count of 0. 4333 */ 4334 static void 4335 unload_object(Obj_Entry *root) 4336 { 4337 Obj_Entry *obj; 4338 Obj_Entry **linkp; 4339 4340 assert(root->refcount == 0); 4341 4342 /* 4343 * Pass over the DAG removing unreferenced objects from 4344 * appropriate lists. 4345 */ 4346 unlink_object(root); 4347 4348 /* Unmap all objects that are no longer referenced. */ 4349 linkp = &obj_list->next; 4350 while ((obj = *linkp) != NULL) { 4351 if (obj->refcount == 0) { 4352 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 4353 obj->path); 4354 dbg("unloading \"%s\"", obj->path); 4355 unload_filtees(root); 4356 munmap(obj->mapbase, obj->mapsize); 4357 linkmap_delete(obj); 4358 *linkp = obj->next; 4359 obj_count--; 4360 obj_free(obj); 4361 } else 4362 linkp = &obj->next; 4363 } 4364 obj_tail = linkp; 4365 } 4366 4367 static void 4368 unlink_object(Obj_Entry *root) 4369 { 4370 Objlist_Entry *elm; 4371 4372 if (root->refcount == 0) { 4373 /* Remove the object from the RTLD_GLOBAL list. */ 4374 objlist_remove(&list_global, root); 4375 4376 /* Remove the object from all objects' DAG lists. */ 4377 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4378 objlist_remove(&elm->obj->dldags, root); 4379 if (elm->obj != root) 4380 unlink_object(elm->obj); 4381 } 4382 } 4383 } 4384 4385 static void 4386 ref_dag(Obj_Entry *root) 4387 { 4388 Objlist_Entry *elm; 4389 4390 assert(root->dag_inited); 4391 STAILQ_FOREACH(elm, &root->dagmembers, link) 4392 elm->obj->refcount++; 4393 } 4394 4395 static void 4396 unref_dag(Obj_Entry *root) 4397 { 4398 Objlist_Entry *elm; 4399 4400 assert(root->dag_inited); 4401 STAILQ_FOREACH(elm, &root->dagmembers, link) 4402 elm->obj->refcount--; 4403 } 4404 4405 /* 4406 * Common code for MD __tls_get_addr(). 4407 */ 4408 void * 4409 tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset) 4410 { 4411 Elf_Addr* dtv = *dtvp; 4412 RtldLockState lockstate; 4413 4414 /* Check dtv generation in case new modules have arrived */ 4415 if (dtv[0] != tls_dtv_generation) { 4416 Elf_Addr* newdtv; 4417 int to_copy; 4418 4419 wlock_acquire(rtld_bind_lock, &lockstate); 4420 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4421 to_copy = dtv[1]; 4422 if (to_copy > tls_max_index) 4423 to_copy = tls_max_index; 4424 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4425 newdtv[0] = tls_dtv_generation; 4426 newdtv[1] = tls_max_index; 4427 free(dtv); 4428 lock_release(rtld_bind_lock, &lockstate); 4429 dtv = *dtvp = newdtv; 4430 } 4431 4432 /* Dynamically allocate module TLS if necessary */ 4433 if (!dtv[index + 1]) { 4434 /* Signal safe, wlock will block out signals. */ 4435 wlock_acquire(rtld_bind_lock, &lockstate); 4436 if (!dtv[index + 1]) 4437 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4438 lock_release(rtld_bind_lock, &lockstate); 4439 } 4440 return ((void *)(dtv[index + 1] + offset)); 4441 } 4442 4443 #if defined(RTLD_STATIC_TLS_VARIANT_II) 4444 4445 /* 4446 * Allocate the static TLS area. Return a pointer to the TCB. The 4447 * static area is based on negative offsets relative to the tcb. 4448 * 4449 * The TCB contains an errno pointer for the system call layer, but because 4450 * we are the RTLD we really have no idea how the caller was compiled so 4451 * the information has to be passed in. errno can either be: 4452 * 4453 * type 0 errno is a simple non-TLS global pointer. 4454 * (special case for e.g. libc_rtld) 4455 * type 1 errno accessed by GOT entry (dynamically linked programs) 4456 * type 2 errno accessed by %gs:OFFSET (statically linked programs) 4457 */ 4458 struct tls_tcb * 4459 allocate_tls(Obj_Entry *objs) 4460 { 4461 Obj_Entry *obj; 4462 size_t data_size; 4463 size_t dtv_size; 4464 struct tls_tcb *tcb; 4465 Elf_Addr *dtv; 4466 Elf_Addr addr; 4467 4468 /* 4469 * Allocate the new TCB. static TLS storage is placed just before the 4470 * TCB to support the %gs:OFFSET (negative offset) model. 4471 */ 4472 data_size = (tls_static_space + RTLD_STATIC_TLS_ALIGN_MASK) & 4473 ~RTLD_STATIC_TLS_ALIGN_MASK; 4474 tcb = malloc(data_size + sizeof(*tcb)); 4475 tcb = (void *)((char *)tcb + data_size); /* actual tcb location */ 4476 4477 dtv_size = (tls_max_index + 2) * sizeof(Elf_Addr); 4478 dtv = malloc(dtv_size); 4479 bzero(dtv, dtv_size); 4480 4481 #ifdef RTLD_TCB_HAS_SELF_POINTER 4482 tcb->tcb_self = tcb; 4483 #endif 4484 tcb->tcb_dtv = dtv; 4485 tcb->tcb_pthread = NULL; 4486 4487 dtv[0] = tls_dtv_generation; 4488 dtv[1] = tls_max_index; 4489 4490 for (obj = objs; obj; obj = obj->next) { 4491 if (obj->tlsoffset) { 4492 addr = (Elf_Addr)tcb - obj->tlsoffset; 4493 memset((void *)(addr + obj->tlsinitsize), 4494 0, obj->tlssize - obj->tlsinitsize); 4495 if (obj->tlsinit) { 4496 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4497 obj->static_tls_copied = true; 4498 } 4499 dtv[obj->tlsindex + 1] = addr; 4500 } 4501 } 4502 return(tcb); 4503 } 4504 4505 void 4506 free_tls(struct tls_tcb *tcb) 4507 { 4508 Elf_Addr *dtv; 4509 int dtv_size, i; 4510 Elf_Addr tls_start, tls_end; 4511 size_t data_size; 4512 4513 data_size = (tls_static_space + RTLD_STATIC_TLS_ALIGN_MASK) & 4514 ~RTLD_STATIC_TLS_ALIGN_MASK; 4515 4516 dtv = tcb->tcb_dtv; 4517 dtv_size = dtv[1]; 4518 tls_end = (Elf_Addr)tcb; 4519 tls_start = (Elf_Addr)tcb - data_size; 4520 for (i = 0; i < dtv_size; i++) { 4521 if (dtv[i+2] != 0 && (dtv[i+2] < tls_start || dtv[i+2] > tls_end)) { 4522 free((void *)dtv[i+2]); 4523 } 4524 } 4525 free(dtv); 4526 4527 free((void*) tls_start); 4528 } 4529 4530 #else 4531 #error "Unsupported TLS layout" 4532 #endif 4533 4534 /* 4535 * Allocate TLS block for module with given index. 4536 */ 4537 void * 4538 allocate_module_tls(int index) 4539 { 4540 Obj_Entry* obj; 4541 char* p; 4542 4543 for (obj = obj_list; obj; obj = obj->next) { 4544 if (obj->tlsindex == index) 4545 break; 4546 } 4547 if (!obj) { 4548 _rtld_error("Can't find module with TLS index %d", index); 4549 die(); 4550 } 4551 4552 p = malloc(obj->tlssize); 4553 if (p == NULL) { 4554 _rtld_error("Cannot allocate TLS block for index %d", index); 4555 die(); 4556 } 4557 memcpy(p, obj->tlsinit, obj->tlsinitsize); 4558 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 4559 4560 return p; 4561 } 4562 4563 bool 4564 allocate_tls_offset(Obj_Entry *obj) 4565 { 4566 size_t off; 4567 4568 if (obj->tls_done) 4569 return true; 4570 4571 if (obj->tlssize == 0) { 4572 obj->tls_done = true; 4573 return true; 4574 } 4575 4576 if (obj->tlsindex == 1) 4577 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 4578 else 4579 off = calculate_tls_offset(tls_last_offset, tls_last_size, 4580 obj->tlssize, obj->tlsalign); 4581 4582 /* 4583 * If we have already fixed the size of the static TLS block, we 4584 * must stay within that size. When allocating the static TLS, we 4585 * leave a small amount of space spare to be used for dynamically 4586 * loading modules which use static TLS. 4587 */ 4588 if (tls_static_space) { 4589 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 4590 return false; 4591 } 4592 4593 tls_last_offset = obj->tlsoffset = off; 4594 tls_last_size = obj->tlssize; 4595 obj->tls_done = true; 4596 4597 return true; 4598 } 4599 4600 void 4601 free_tls_offset(Obj_Entry *obj) 4602 { 4603 #ifdef RTLD_STATIC_TLS_VARIANT_II 4604 /* 4605 * If we were the last thing to allocate out of the static TLS 4606 * block, we give our space back to the 'allocator'. This is a 4607 * simplistic workaround to allow libGL.so.1 to be loaded and 4608 * unloaded multiple times. We only handle the Variant II 4609 * mechanism for now - this really needs a proper allocator. 4610 */ 4611 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 4612 == calculate_tls_end(tls_last_offset, tls_last_size)) { 4613 tls_last_offset -= obj->tlssize; 4614 tls_last_size = 0; 4615 } 4616 #endif 4617 } 4618 4619 struct tls_tcb * 4620 _rtld_allocate_tls(void) 4621 { 4622 struct tls_tcb *new_tcb; 4623 RtldLockState lockstate; 4624 4625 wlock_acquire(rtld_bind_lock, &lockstate); 4626 new_tcb = allocate_tls(obj_list); 4627 lock_release(rtld_bind_lock, &lockstate); 4628 4629 return (new_tcb); 4630 } 4631 4632 void 4633 _rtld_free_tls(struct tls_tcb *tcb) 4634 { 4635 RtldLockState lockstate; 4636 4637 wlock_acquire(rtld_bind_lock, &lockstate); 4638 free_tls(tcb); 4639 lock_release(rtld_bind_lock, &lockstate); 4640 } 4641 4642 static void 4643 object_add_name(Obj_Entry *obj, const char *name) 4644 { 4645 Name_Entry *entry; 4646 size_t len; 4647 4648 len = strlen(name); 4649 entry = malloc(sizeof(Name_Entry) + len); 4650 4651 if (entry != NULL) { 4652 strcpy(entry->name, name); 4653 STAILQ_INSERT_TAIL(&obj->names, entry, link); 4654 } 4655 } 4656 4657 static int 4658 object_match_name(const Obj_Entry *obj, const char *name) 4659 { 4660 Name_Entry *entry; 4661 4662 STAILQ_FOREACH(entry, &obj->names, link) { 4663 if (strcmp(name, entry->name) == 0) 4664 return (1); 4665 } 4666 return (0); 4667 } 4668 4669 static Obj_Entry * 4670 locate_dependency(const Obj_Entry *obj, const char *name) 4671 { 4672 const Objlist_Entry *entry; 4673 const Needed_Entry *needed; 4674 4675 STAILQ_FOREACH(entry, &list_main, link) { 4676 if (object_match_name(entry->obj, name)) 4677 return entry->obj; 4678 } 4679 4680 for (needed = obj->needed; needed != NULL; needed = needed->next) { 4681 if (strcmp(obj->strtab + needed->name, name) == 0 || 4682 (needed->obj != NULL && object_match_name(needed->obj, name))) { 4683 /* 4684 * If there is DT_NEEDED for the name we are looking for, 4685 * we are all set. Note that object might not be found if 4686 * dependency was not loaded yet, so the function can 4687 * return NULL here. This is expected and handled 4688 * properly by the caller. 4689 */ 4690 return (needed->obj); 4691 } 4692 } 4693 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 4694 obj->path, name); 4695 die(); 4696 } 4697 4698 static int 4699 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 4700 const Elf_Vernaux *vna) 4701 { 4702 const Elf_Verdef *vd; 4703 const char *vername; 4704 4705 vername = refobj->strtab + vna->vna_name; 4706 vd = depobj->verdef; 4707 if (vd == NULL) { 4708 _rtld_error("%s: version %s required by %s not defined", 4709 depobj->path, vername, refobj->path); 4710 return (-1); 4711 } 4712 for (;;) { 4713 if (vd->vd_version != VER_DEF_CURRENT) { 4714 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4715 depobj->path, vd->vd_version); 4716 return (-1); 4717 } 4718 if (vna->vna_hash == vd->vd_hash) { 4719 const Elf_Verdaux *aux = (const Elf_Verdaux *) 4720 ((char *)vd + vd->vd_aux); 4721 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 4722 return (0); 4723 } 4724 if (vd->vd_next == 0) 4725 break; 4726 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4727 } 4728 if (vna->vna_flags & VER_FLG_WEAK) 4729 return (0); 4730 _rtld_error("%s: version %s required by %s not found", 4731 depobj->path, vername, refobj->path); 4732 return (-1); 4733 } 4734 4735 static int 4736 rtld_verify_object_versions(Obj_Entry *obj) 4737 { 4738 const Elf_Verneed *vn; 4739 const Elf_Verdef *vd; 4740 const Elf_Verdaux *vda; 4741 const Elf_Vernaux *vna; 4742 const Obj_Entry *depobj; 4743 int maxvernum, vernum; 4744 4745 if (obj->ver_checked) 4746 return (0); 4747 obj->ver_checked = true; 4748 4749 maxvernum = 0; 4750 /* 4751 * Walk over defined and required version records and figure out 4752 * max index used by any of them. Do very basic sanity checking 4753 * while there. 4754 */ 4755 vn = obj->verneed; 4756 while (vn != NULL) { 4757 if (vn->vn_version != VER_NEED_CURRENT) { 4758 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 4759 obj->path, vn->vn_version); 4760 return (-1); 4761 } 4762 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4763 for (;;) { 4764 vernum = VER_NEED_IDX(vna->vna_other); 4765 if (vernum > maxvernum) 4766 maxvernum = vernum; 4767 if (vna->vna_next == 0) 4768 break; 4769 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4770 } 4771 if (vn->vn_next == 0) 4772 break; 4773 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4774 } 4775 4776 vd = obj->verdef; 4777 while (vd != NULL) { 4778 if (vd->vd_version != VER_DEF_CURRENT) { 4779 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4780 obj->path, vd->vd_version); 4781 return (-1); 4782 } 4783 vernum = VER_DEF_IDX(vd->vd_ndx); 4784 if (vernum > maxvernum) 4785 maxvernum = vernum; 4786 if (vd->vd_next == 0) 4787 break; 4788 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4789 } 4790 4791 if (maxvernum == 0) 4792 return (0); 4793 4794 /* 4795 * Store version information in array indexable by version index. 4796 * Verify that object version requirements are satisfied along the 4797 * way. 4798 */ 4799 obj->vernum = maxvernum + 1; 4800 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 4801 4802 vd = obj->verdef; 4803 while (vd != NULL) { 4804 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 4805 vernum = VER_DEF_IDX(vd->vd_ndx); 4806 assert(vernum <= maxvernum); 4807 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 4808 obj->vertab[vernum].hash = vd->vd_hash; 4809 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 4810 obj->vertab[vernum].file = NULL; 4811 obj->vertab[vernum].flags = 0; 4812 } 4813 if (vd->vd_next == 0) 4814 break; 4815 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4816 } 4817 4818 vn = obj->verneed; 4819 while (vn != NULL) { 4820 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 4821 if (depobj == NULL) 4822 return (-1); 4823 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4824 for (;;) { 4825 if (check_object_provided_version(obj, depobj, vna)) 4826 return (-1); 4827 vernum = VER_NEED_IDX(vna->vna_other); 4828 assert(vernum <= maxvernum); 4829 obj->vertab[vernum].hash = vna->vna_hash; 4830 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 4831 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 4832 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 4833 VER_INFO_HIDDEN : 0; 4834 if (vna->vna_next == 0) 4835 break; 4836 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4837 } 4838 if (vn->vn_next == 0) 4839 break; 4840 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4841 } 4842 return 0; 4843 } 4844 4845 static int 4846 rtld_verify_versions(const Objlist *objlist) 4847 { 4848 Objlist_Entry *entry; 4849 int rc; 4850 4851 rc = 0; 4852 STAILQ_FOREACH(entry, objlist, link) { 4853 /* 4854 * Skip dummy objects or objects that have their version requirements 4855 * already checked. 4856 */ 4857 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 4858 continue; 4859 if (rtld_verify_object_versions(entry->obj) == -1) { 4860 rc = -1; 4861 if (ld_tracing == NULL) 4862 break; 4863 } 4864 } 4865 if (rc == 0 || ld_tracing != NULL) 4866 rc = rtld_verify_object_versions(&obj_rtld); 4867 return rc; 4868 } 4869 4870 const Ver_Entry * 4871 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 4872 { 4873 Elf_Versym vernum; 4874 4875 if (obj->vertab) { 4876 vernum = VER_NDX(obj->versyms[symnum]); 4877 if (vernum >= obj->vernum) { 4878 _rtld_error("%s: symbol %s has wrong verneed value %d", 4879 obj->path, obj->strtab + symnum, vernum); 4880 } else if (obj->vertab[vernum].hash != 0) { 4881 return &obj->vertab[vernum]; 4882 } 4883 } 4884 return NULL; 4885 } 4886 4887 int 4888 _rtld_get_stack_prot(void) 4889 { 4890 4891 return (stack_prot); 4892 } 4893 4894 static void 4895 map_stacks_exec(RtldLockState *lockstate) 4896 { 4897 return; 4898 /* 4899 * Stack protection must be implemented in the kernel before the dynamic 4900 * linker can handle PT_GNU_STACK sections. 4901 * The following is the FreeBSD implementation of map_stacks_exec() 4902 * void (*thr_map_stacks_exec)(void); 4903 * 4904 * if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 4905 * return; 4906 * thr_map_stacks_exec = (void (*)(void))(uintptr_t) 4907 * get_program_var_addr("__pthread_map_stacks_exec", lockstate); 4908 * if (thr_map_stacks_exec != NULL) { 4909 * stack_prot |= PROT_EXEC; 4910 * thr_map_stacks_exec(); 4911 * } 4912 */ 4913 } 4914 4915 /* 4916 * Only called after all primary shared libraries are loaded (EARLY is 4917 * not set). Resolves the static TLS distribution function at first-call. 4918 * This is typically a weak libc symbol that is overrideen by the threading 4919 * library. 4920 */ 4921 static void 4922 distribute_static_tls(Objlist *list, RtldLockState *lockstate) 4923 { 4924 Objlist_Entry *elm; 4925 Obj_Entry *obj; 4926 static void (*dtlsfunc)(size_t, void *, size_t, size_t); 4927 4928 /* 4929 * First time, resolve "_pthread_distribute_static_tls". 4930 */ 4931 if (dtlsfunc == NULL) { 4932 dtlsfunc = (void *)dlfunc(RTLD_ALL, 4933 "_pthread_distribute_static_tls"); 4934 if (dtlsfunc == NULL) 4935 return; 4936 } 4937 4938 /* 4939 * Initialize static TLS data for the object list using the callback 4940 * function (to either libc or pthreads). 4941 */ 4942 STAILQ_FOREACH(elm, list, link) { 4943 obj = elm->obj; 4944 if (/*obj->marker ||*/ !obj->tls_done || obj->static_tls_copied) 4945 continue; 4946 dtlsfunc(obj->tlsoffset, obj->tlsinit, 4947 obj->tlsinitsize, obj->tlssize); 4948 obj->static_tls_copied = true; 4949 } 4950 } 4951 4952 void 4953 symlook_init(SymLook *dst, const char *name) 4954 { 4955 4956 bzero(dst, sizeof(*dst)); 4957 dst->name = name; 4958 dst->hash = elf_hash(name); 4959 dst->hash_gnu = gnu_hash(name); 4960 } 4961 4962 static void 4963 symlook_init_from_req(SymLook *dst, const SymLook *src) 4964 { 4965 4966 dst->name = src->name; 4967 dst->hash = src->hash; 4968 dst->hash_gnu = src->hash_gnu; 4969 dst->ventry = src->ventry; 4970 dst->flags = src->flags; 4971 dst->defobj_out = NULL; 4972 dst->sym_out = NULL; 4973 dst->lockstate = src->lockstate; 4974 } 4975 4976 4977 /* 4978 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 4979 */ 4980 static int 4981 parse_libdir(const char *str) 4982 { 4983 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 4984 const char *orig; 4985 int fd; 4986 char c; 4987 4988 orig = str; 4989 fd = 0; 4990 for (c = *str; c != '\0'; c = *++str) { 4991 if (c < '0' || c > '9') 4992 return (-1); 4993 4994 fd *= RADIX; 4995 fd += c - '0'; 4996 } 4997 4998 /* Make sure we actually parsed something. */ 4999 if (str == orig) { 5000 _rtld_error("failed to parse directory FD from '%s'", str); 5001 return (-1); 5002 } 5003 return (fd); 5004 } 5005 5006 #ifdef ENABLE_OSRELDATE 5007 /* 5008 * Overrides for libc_pic-provided functions. 5009 */ 5010 5011 int 5012 __getosreldate(void) 5013 { 5014 size_t len; 5015 int oid[2]; 5016 int error, osrel; 5017 5018 if (osreldate != 0) 5019 return (osreldate); 5020 5021 oid[0] = CTL_KERN; 5022 oid[1] = KERN_OSRELDATE; 5023 osrel = 0; 5024 len = sizeof(osrel); 5025 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 5026 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 5027 osreldate = osrel; 5028 return (osreldate); 5029 } 5030 #endif 5031 5032 /* 5033 * Ask the kernel for the extra tls space to allocate after calculating 5034 * base tls requirements in rtld-elf. 5.9 or later. 5035 */ 5036 static int 5037 __getstatictlsextra(void) 5038 { 5039 size_t len; 5040 int oid[2]; 5041 int error; 5042 int tls_extra; 5043 5044 oid[0] = CTL_KERN; 5045 oid[1] = KERN_STATIC_TLS_EXTRA; 5046 len = sizeof(tls_extra); 5047 error = sysctl(oid, 2, &tls_extra, &len, NULL, 0); 5048 if (error || len != sizeof(tls_extra)) 5049 tls_extra = RTLD_STATIC_TLS_EXTRA_DEFAULT; 5050 if (tls_extra < RTLD_STATIC_TLS_EXTRA_MIN) 5051 tls_extra = RTLD_STATIC_TLS_EXTRA_MIN; 5052 if (tls_extra > RTLD_STATIC_TLS_EXTRA_MAX) 5053 tls_extra = RTLD_STATIC_TLS_EXTRA_MAX; 5054 return tls_extra; 5055 } 5056 5057 /* 5058 * No unresolved symbols for rtld. 5059 */ 5060 void 5061 __pthread_cxa_finalize(struct dl_phdr_info *a) 5062 { 5063 } 5064 5065 const char * 5066 rtld_strerror(int errnum) 5067 { 5068 5069 if (errnum < 0 || errnum >= sys_nerr) 5070 return ("Unknown error"); 5071 return (sys_errlist[errnum]); 5072 } 5073