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/uio.h> 47 #include <sys/utsname.h> 48 #include <sys/ktrace.h> 49 #include <sys/resident.h> 50 #include <sys/tls.h> 51 52 #include <machine/tls.h> 53 54 #include <dlfcn.h> 55 #include <err.h> 56 #include <errno.h> 57 #include <fcntl.h> 58 #include <stdarg.h> 59 #include <stdio.h> 60 #include <stdlib.h> 61 #include <string.h> 62 #include <unistd.h> 63 64 #include "debug.h" 65 #include "rtld.h" 66 #include "libmap.h" 67 #include "rtld_printf.h" 68 #include "notes.h" 69 70 #define PATH_RTLD "/usr/libexec/ld-elf.so.2" 71 #define LD_ARY_CACHE 16 72 73 /* Types. */ 74 typedef void (*func_ptr_type)(); 75 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 76 77 /* 78 * Function declarations. 79 */ 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 Obj_Entry *dlcheck(void *); 89 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, 90 int lo_flags, int mode, RtldLockState *lockstate); 91 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 92 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 93 static bool donelist_check(DoneList *, const Obj_Entry *); 94 static void errmsg_restore(char *); 95 static char *errmsg_save(void); 96 static void *fill_search_info(const char *, size_t, void *); 97 static char *find_library(const char *, const Obj_Entry *, int *); 98 static const char *gethints(bool); 99 static void init_dag(Obj_Entry *); 100 static void init_rtld(caddr_t, Elf_Auxinfo **); 101 static void initlist_add_neededs(Needed_Entry *, Objlist *); 102 static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *); 103 static void linkmap_add(Obj_Entry *); 104 static void linkmap_delete(Obj_Entry *); 105 static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 106 static void unload_filtees(Obj_Entry *); 107 static int load_needed_objects(Obj_Entry *, int); 108 static int load_preload_objects(void); 109 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 110 static void map_stacks_exec(RtldLockState *); 111 static Obj_Entry *obj_from_addr(const void *); 112 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 113 static void objlist_call_init(Objlist *, RtldLockState *); 114 static void objlist_clear(Objlist *); 115 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 116 static void objlist_init(Objlist *); 117 static void objlist_push_head(Objlist *, Obj_Entry *); 118 static void objlist_push_tail(Objlist *, Obj_Entry *); 119 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 120 static void objlist_remove(Objlist *, Obj_Entry *); 121 static int parse_libdir(const char *); 122 static void *path_enumerate(const char *, path_enum_proc, void *); 123 static int relocate_object_dag(Obj_Entry *root, bool bind_now, 124 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 125 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 126 int flags, RtldLockState *lockstate); 127 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 128 RtldLockState *); 129 static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now, 130 int flags, RtldLockState *lockstate); 131 static int rtld_dirname(const char *, char *); 132 static int rtld_dirname_abs(const char *, char *); 133 static void *rtld_dlopen(const char *name, int fd, int mode); 134 static void rtld_exit(void); 135 static char *search_library_path(const char *, const char *); 136 static char *search_library_pathfds(const char *, const char *, int *); 137 static const void **get_program_var_addr(const char *, RtldLockState *); 138 static void set_program_var(const char *, const void *); 139 static int symlook_default(SymLook *, const Obj_Entry *refobj); 140 static int symlook_global(SymLook *, DoneList *); 141 static void symlook_init_from_req(SymLook *, const SymLook *); 142 static int symlook_list(SymLook *, const Objlist *, DoneList *); 143 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 144 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 145 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 146 static void trace_loaded_objects(Obj_Entry *); 147 static void unlink_object(Obj_Entry *); 148 static void unload_object(Obj_Entry *); 149 static void unref_dag(Obj_Entry *); 150 static void ref_dag(Obj_Entry *); 151 static char *origin_subst_one(char *, const char *, const char *, bool); 152 static char *origin_subst(char *, const char *); 153 static void preinit_main(void); 154 static int rtld_verify_versions(const Objlist *); 155 static int rtld_verify_object_versions(Obj_Entry *); 156 static void object_add_name(Obj_Entry *, const char *); 157 static int object_match_name(const Obj_Entry *, const char *); 158 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 159 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 160 struct dl_phdr_info *phdr_info); 161 static uint_fast32_t gnu_hash (const char *); 162 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 163 const unsigned long); 164 165 void r_debug_state(struct r_debug *, struct link_map *) __noinline; 166 void _r_debug_postinit(struct link_map *) __noinline; 167 168 /* 169 * Data declarations. 170 */ 171 static char *error_message; /* Message for dlerror(), or NULL */ 172 struct r_debug r_debug; /* for GDB; */ 173 static bool libmap_disable; /* Disable libmap */ 174 static bool ld_loadfltr; /* Immediate filters processing */ 175 static char *libmap_override; /* Maps to use in addition to libmap.conf */ 176 static bool trust; /* False for setuid and setgid programs */ 177 static bool dangerous_ld_env; /* True if environment variables have been 178 used to affect the libraries loaded */ 179 static const char *ld_bind_now; /* Environment variable for immediate binding */ 180 static const char *ld_debug; /* Environment variable for debugging */ 181 static const char *ld_library_path; /* Environment variable for search path */ 182 static const char *ld_library_dirs; /* Env variable for library descriptors */ 183 static char *ld_preload; /* Environment variable for libraries to 184 load first */ 185 static const char *ld_elf_hints_path; /* Env var. for alternative hints path */ 186 static const char *ld_tracing; /* Called from ldd to print libs */ 187 static const char *ld_utrace; /* Use utrace() to log events. */ 188 static int (*rtld_functrace)( /* Optional function call tracing hook */ 189 const char *caller_obj, 190 const char *callee_obj, 191 const char *callee_func, 192 void *stack); 193 static const Obj_Entry *rtld_functrace_obj; /* Object thereof */ 194 static Obj_Entry *obj_list; /* Head of linked list of shared objects */ 195 static Obj_Entry **obj_tail; /* Link field of last object in list */ 196 static Obj_Entry **preload_tail; 197 static Obj_Entry *obj_main; /* The main program shared object */ 198 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 199 static unsigned int obj_count; /* Number of objects in obj_list */ 200 static unsigned int obj_loads; /* Number of objects in obj_list */ 201 202 static int ld_resident; /* Non-zero if resident */ 203 static const char *ld_ary[LD_ARY_CACHE]; 204 static int ld_index; 205 static Objlist initlist; 206 207 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 208 STAILQ_HEAD_INITIALIZER(list_global); 209 static Objlist list_main = /* Objects loaded at program startup */ 210 STAILQ_HEAD_INITIALIZER(list_main); 211 static Objlist list_fini = /* Objects needing fini() calls */ 212 STAILQ_HEAD_INITIALIZER(list_fini); 213 214 static Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 215 const char *__ld_sharedlib_base; 216 217 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 218 219 extern Elf_Dyn _DYNAMIC; 220 #pragma weak _DYNAMIC 221 #ifndef RTLD_IS_DYNAMIC 222 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL) 223 #endif 224 225 #ifdef ENABLE_OSRELDATE 226 int osreldate; 227 #endif 228 229 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 230 #if 0 231 static int max_stack_flags; 232 #endif 233 234 /* 235 * Global declarations normally provided by crt1. The dynamic linker is 236 * not built with crt1, so we have to provide them ourselves. 237 */ 238 char *__progname; 239 char **environ; 240 241 /* 242 * Used to pass argc, argv to init functions. 243 */ 244 int main_argc; 245 char **main_argv; 246 247 /* 248 * Globals to control TLS allocation. 249 */ 250 size_t tls_last_offset; /* Static TLS offset of last module */ 251 size_t tls_last_size; /* Static TLS size of last module */ 252 size_t tls_static_space; /* Static TLS space allocated */ 253 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 254 int tls_max_index = 1; /* Largest module index allocated */ 255 256 /* 257 * Fill in a DoneList with an allocation large enough to hold all of 258 * the currently-loaded objects. Keep this as a macro since it calls 259 * alloca and we want that to occur within the scope of the caller. 260 */ 261 #define donelist_init(dlp) \ 262 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 263 assert((dlp)->objs != NULL), \ 264 (dlp)->num_alloc = obj_count, \ 265 (dlp)->num_used = 0) 266 267 #define UTRACE_DLOPEN_START 1 268 #define UTRACE_DLOPEN_STOP 2 269 #define UTRACE_DLCLOSE_START 3 270 #define UTRACE_DLCLOSE_STOP 4 271 #define UTRACE_LOAD_OBJECT 5 272 #define UTRACE_UNLOAD_OBJECT 6 273 #define UTRACE_ADD_RUNDEP 7 274 #define UTRACE_PRELOAD_FINISHED 8 275 #define UTRACE_INIT_CALL 9 276 #define UTRACE_FINI_CALL 10 277 278 struct utrace_rtld { 279 char sig[4]; /* 'RTLD' */ 280 int event; 281 void *handle; 282 void *mapbase; /* Used for 'parent' and 'init/fini' */ 283 size_t mapsize; 284 int refcnt; /* Used for 'mode' */ 285 char name[MAXPATHLEN]; 286 }; 287 288 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 289 if (ld_utrace != NULL) \ 290 ld_utrace_log(e, h, mb, ms, r, n); \ 291 } while (0) 292 293 static void 294 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 295 int refcnt, const char *name) 296 { 297 struct utrace_rtld ut; 298 299 ut.sig[0] = 'R'; 300 ut.sig[1] = 'T'; 301 ut.sig[2] = 'L'; 302 ut.sig[3] = 'D'; 303 ut.event = event; 304 ut.handle = handle; 305 ut.mapbase = mapbase; 306 ut.mapsize = mapsize; 307 ut.refcnt = refcnt; 308 bzero(ut.name, sizeof(ut.name)); 309 if (name) 310 strlcpy(ut.name, name, sizeof(ut.name)); 311 utrace(&ut, sizeof(ut)); 312 } 313 314 /* 315 * Main entry point for dynamic linking. The first argument is the 316 * stack pointer. The stack is expected to be laid out as described 317 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 318 * Specifically, the stack pointer points to a word containing 319 * ARGC. Following that in the stack is a null-terminated sequence 320 * of pointers to argument strings. Then comes a null-terminated 321 * sequence of pointers to environment strings. Finally, there is a 322 * sequence of "auxiliary vector" entries. 323 * 324 * The second argument points to a place to store the dynamic linker's 325 * exit procedure pointer and the third to a place to store the main 326 * program's object. 327 * 328 * The return value is the main program's entry point. 329 */ 330 func_ptr_type 331 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 332 { 333 Elf_Auxinfo *aux_info[AT_COUNT]; 334 int i; 335 int argc; 336 char **argv; 337 char **env; 338 Elf_Auxinfo *aux; 339 Elf_Auxinfo *auxp; 340 const char *argv0; 341 Objlist_Entry *entry; 342 Obj_Entry *obj; 343 Obj_Entry *last_interposer; 344 345 /* marino: DO NOT MOVE THESE VARIABLES TO _rtld 346 Obj_Entry **preload_tail; 347 Objlist initlist; 348 from global to here. It will break the DWARF2 unwind scheme. 349 */ 350 351 /* 352 * On entry, the dynamic linker itself has not been relocated yet. 353 * Be very careful not to reference any global data until after 354 * init_rtld has returned. It is OK to reference file-scope statics 355 * and string constants, and to call static and global functions. 356 */ 357 358 /* Find the auxiliary vector on the stack. */ 359 argc = *sp++; 360 argv = (char **) sp; 361 sp += argc + 1; /* Skip over arguments and NULL terminator */ 362 env = (char **) sp; 363 364 /* 365 * If we aren't already resident we have to dig out some more info. 366 * Note that auxinfo does not exist when we are resident. 367 * 368 * I'm not sure about the ld_resident check. It seems to read zero 369 * prior to relocation, which is what we want. When running from a 370 * resident copy everything will be relocated so we are definitely 371 * good there. 372 */ 373 if (ld_resident == 0) { 374 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 375 ; 376 aux = (Elf_Auxinfo *) sp; 377 378 /* Digest the auxiliary vector. */ 379 for (i = 0; i < AT_COUNT; i++) 380 aux_info[i] = NULL; 381 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 382 if (auxp->a_type < AT_COUNT) 383 aux_info[auxp->a_type] = auxp; 384 } 385 386 /* Initialize and relocate ourselves. */ 387 assert(aux_info[AT_BASE] != NULL); 388 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 389 } 390 391 ld_index = 0; /* don't use old env cache in case we are resident */ 392 __progname = obj_rtld.path; 393 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 394 environ = env; 395 main_argc = argc; 396 main_argv = argv; 397 398 trust = !issetugid(); 399 400 ld_bind_now = _getenv_ld("LD_BIND_NOW"); 401 /* 402 * If the process is tainted, then we un-set the dangerous environment 403 * variables. The process will be marked as tainted until setuid(2) 404 * is called. If any child process calls setuid(2) we do not want any 405 * future processes to honor the potentially un-safe variables. 406 */ 407 if (!trust) { 408 if ( unsetenv("LD_DEBUG") 409 || unsetenv("LD_PRELOAD") 410 || unsetenv("LD_LIBRARY_PATH") 411 || unsetenv("LD_LIBRARY_PATH_FDS") 412 || unsetenv("LD_ELF_HINTS_PATH") 413 || unsetenv("LD_LIBMAP") 414 || unsetenv("LD_LIBMAP_DISABLE") 415 || unsetenv("LD_LOADFLTR") 416 || unsetenv("LD_SHAREDLIB_BASE") 417 ) { 418 _rtld_error("environment corrupt; aborting"); 419 die(); 420 } 421 } 422 __ld_sharedlib_base = _getenv_ld("LD_SHAREDLIB_BASE"); 423 ld_debug = _getenv_ld("LD_DEBUG"); 424 libmap_disable = _getenv_ld("LD_LIBMAP_DISABLE") != NULL; 425 libmap_override = (char *)_getenv_ld("LD_LIBMAP"); 426 ld_library_path = _getenv_ld("LD_LIBRARY_PATH"); 427 ld_library_dirs = _getenv_ld("LD_LIBRARY_PATH_FDS"); 428 ld_preload = (char *)_getenv_ld("LD_PRELOAD"); 429 ld_elf_hints_path = _getenv_ld("LD_ELF_HINTS_PATH"); 430 ld_loadfltr = _getenv_ld("LD_LOADFLTR") != NULL; 431 dangerous_ld_env = (ld_library_path != NULL) 432 || (ld_preload != NULL) 433 || (ld_elf_hints_path != NULL) 434 || ld_loadfltr 435 || (libmap_override != NULL) 436 || libmap_disable 437 ; 438 ld_tracing = _getenv_ld("LD_TRACE_LOADED_OBJECTS"); 439 ld_utrace = _getenv_ld("LD_UTRACE"); 440 441 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 442 ld_elf_hints_path = _PATH_ELF_HINTS; 443 444 if (ld_debug != NULL && *ld_debug != '\0') 445 debug = 1; 446 dbg("%s is initialized, base address = %p", __progname, 447 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 448 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 449 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 450 451 dbg("initializing thread locks"); 452 lockdflt_init(); 453 454 /* 455 * If we are resident we can skip work that we have already done. 456 * Note that the stack is reset and there is no Elf_Auxinfo 457 * when running from a resident image, and the static globals setup 458 * between here and resident_skip will have already been setup. 459 */ 460 if (ld_resident) 461 goto resident_skip1; 462 463 /* 464 * Load the main program, or process its program header if it is 465 * already loaded. 466 */ 467 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */ 468 int fd = aux_info[AT_EXECFD]->a_un.a_val; 469 dbg("loading main program"); 470 obj_main = map_object(fd, argv0, NULL); 471 close(fd); 472 if (obj_main == NULL) 473 die(); 474 #if 0 475 max_stack_flags = obj_main->stack_flags; 476 #endif 477 } else { /* Main program already loaded. */ 478 const Elf_Phdr *phdr; 479 int phnum; 480 caddr_t entry; 481 482 dbg("processing main program's program header"); 483 assert(aux_info[AT_PHDR] != NULL); 484 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 485 assert(aux_info[AT_PHNUM] != NULL); 486 phnum = aux_info[AT_PHNUM]->a_un.a_val; 487 assert(aux_info[AT_PHENT] != NULL); 488 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 489 assert(aux_info[AT_ENTRY] != NULL); 490 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 491 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL) 492 die(); 493 } 494 495 char buf[MAXPATHLEN]; 496 if (aux_info[AT_EXECPATH] != NULL) { 497 char *kexecpath; 498 499 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 500 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 501 if (kexecpath[0] == '/') 502 obj_main->path = kexecpath; 503 else if (getcwd(buf, sizeof(buf)) == NULL || 504 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 505 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 506 obj_main->path = xstrdup(argv0); 507 else 508 obj_main->path = xstrdup(buf); 509 } else { 510 char resolved[MAXPATHLEN]; 511 dbg("No AT_EXECPATH"); 512 if (argv0[0] == '/') { 513 if (realpath(argv0, resolved) != NULL) 514 obj_main->path = xstrdup(resolved); 515 else 516 obj_main->path = xstrdup(argv0); 517 } else { 518 if (getcwd(buf, sizeof(buf)) != NULL 519 && strlcat(buf, "/", sizeof(buf)) < sizeof(buf) 520 && strlcat(buf, argv0, sizeof (buf)) < sizeof(buf) 521 && access(buf, R_OK) == 0 522 && realpath(buf, resolved) != NULL) 523 obj_main->path = xstrdup(resolved); 524 else 525 obj_main->path = xstrdup(argv0); 526 } 527 } 528 dbg("obj_main path %s", obj_main->path); 529 obj_main->mainprog = true; 530 531 if (aux_info[AT_STACKPROT] != NULL && 532 aux_info[AT_STACKPROT]->a_un.a_val != 0) 533 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 534 535 /* 536 * Get the actual dynamic linker pathname from the executable if 537 * possible. (It should always be possible.) That ensures that 538 * gdb will find the right dynamic linker even if a non-standard 539 * one is being used. 540 */ 541 if (obj_main->interp != NULL && 542 strcmp(obj_main->interp, obj_rtld.path) != 0) { 543 free(obj_rtld.path); 544 obj_rtld.path = xstrdup(obj_main->interp); 545 __progname = obj_rtld.path; 546 } 547 548 digest_dynamic(obj_main, 0); 549 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 550 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 551 obj_main->dynsymcount); 552 553 linkmap_add(obj_main); 554 linkmap_add(&obj_rtld); 555 556 /* Link the main program into the list of objects. */ 557 *obj_tail = obj_main; 558 obj_tail = &obj_main->next; 559 obj_count++; 560 obj_loads++; 561 562 /* Initialize a fake symbol for resolving undefined weak references. */ 563 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 564 sym_zero.st_shndx = SHN_UNDEF; 565 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 566 567 if (!libmap_disable) 568 libmap_disable = (bool)lm_init(libmap_override); 569 570 dbg("loading LD_PRELOAD libraries"); 571 if (load_preload_objects() == -1) 572 die(); 573 preload_tail = obj_tail; 574 575 dbg("loading needed objects"); 576 if (load_needed_objects(obj_main, 0) == -1) 577 die(); 578 579 /* Make a list of all objects loaded at startup. */ 580 last_interposer = obj_main; 581 for (obj = obj_list; obj != NULL; obj = obj->next) { 582 if (obj->z_interpose && obj != obj_main) { 583 objlist_put_after(&list_main, last_interposer, obj); 584 last_interposer = obj; 585 } else { 586 objlist_push_tail(&list_main, obj); 587 } 588 obj->refcount++; 589 } 590 591 dbg("checking for required versions"); 592 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 593 die(); 594 595 resident_skip1: 596 597 if (ld_tracing) { /* We're done */ 598 trace_loaded_objects(obj_main); 599 exit(0); 600 } 601 602 if (ld_resident) /* XXX clean this up! */ 603 goto resident_skip2; 604 605 if (_getenv_ld("LD_DUMP_REL_PRE") != NULL) { 606 dump_relocations(obj_main); 607 exit (0); 608 } 609 610 /* setup TLS for main thread */ 611 dbg("initializing initial thread local storage"); 612 STAILQ_FOREACH(entry, &list_main, link) { 613 /* 614 * Allocate all the initial objects out of the static TLS 615 * block even if they didn't ask for it. 616 */ 617 allocate_tls_offset(entry->obj); 618 } 619 620 tls_static_space = tls_last_offset + RTLD_STATIC_TLS_EXTRA; 621 622 /* 623 * Do not try to allocate the TLS here, let libc do it itself. 624 * (crt1 for the program will call _init_tls()) 625 */ 626 627 if (relocate_objects(obj_main, 628 ld_bind_now != NULL && *ld_bind_now != '\0', 629 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 630 die(); 631 632 dbg("doing copy relocations"); 633 if (do_copy_relocations(obj_main) == -1) 634 die(); 635 636 resident_skip2: 637 638 if (_getenv_ld("LD_RESIDENT_UNREGISTER_NOW")) { 639 if (exec_sys_unregister(-1) < 0) { 640 dbg("exec_sys_unregister failed %d\n", errno); 641 exit(errno); 642 } 643 dbg("exec_sys_unregister success\n"); 644 exit(0); 645 } 646 647 if (_getenv_ld("LD_DUMP_REL_POST") != NULL) { 648 dump_relocations(obj_main); 649 exit (0); 650 } 651 652 dbg("initializing key program variables"); 653 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 654 set_program_var("environ", env); 655 set_program_var("__elf_aux_vector", aux); 656 657 if (_getenv_ld("LD_RESIDENT_REGISTER_NOW")) { 658 extern void resident_start(void); 659 ld_resident = 1; 660 if (exec_sys_register(resident_start) < 0) { 661 dbg("exec_sys_register failed %d\n", errno); 662 exit(errno); 663 } 664 dbg("exec_sys_register success\n"); 665 exit(0); 666 } 667 668 /* Make a list of init functions to call. */ 669 objlist_init(&initlist); 670 initlist_add_objects(obj_list, preload_tail, &initlist); 671 672 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 673 674 map_stacks_exec(NULL); 675 676 dbg("resolving ifuncs"); 677 { 678 RtldLockState lockstate; 679 680 wlock_acquire(rtld_bind_lock, &lockstate); 681 if (resolve_objects_ifunc( 682 obj_main, 683 (ld_bind_now != NULL && *ld_bind_now != '\0'), 684 SYMLOOK_EARLY, 685 &lockstate) == -1) { 686 die(); 687 } 688 lock_release(rtld_bind_lock, &lockstate); 689 } 690 691 /* 692 * Do NOT call the initlist here, give libc a chance to set up 693 * the initial TLS segment. crt1 will then call _rtld_call_init(). 694 */ 695 696 dbg("transferring control to program entry point = %p", obj_main->entry); 697 698 /* Return the exit procedure and the program entry point. */ 699 *exit_proc = rtld_exit; 700 *objp = obj_main; 701 return (func_ptr_type) obj_main->entry; 702 } 703 704 /* 705 * Call the initialization list for dynamically loaded libraries. 706 * (called from crt1.c). 707 */ 708 void 709 _rtld_call_init(void) 710 { 711 RtldLockState lockstate; 712 Obj_Entry *obj; 713 714 if (!obj_main->note_present && obj_main->valid_hash_gnu) { 715 /* 716 * The use of a linker script with a PHDRS directive that does not include 717 * PT_NOTE will block the crt_no_init note. In this case we'll look for the 718 * recently added GNU hash dynamic tag which gets built by default. It is 719 * extremely unlikely to find a pre-3.1 binary without a PT_NOTE header and 720 * a gnu hash tag. If gnu hash found, consider binary to use new crt code. 721 */ 722 obj_main->crt_no_init = true; 723 dbg("Setting crt_no_init without presence of PT_NOTE header"); 724 } 725 726 wlock_acquire(rtld_bind_lock, &lockstate); 727 if (obj_main->crt_no_init) 728 preinit_main(); 729 else { 730 /* 731 * Make sure we don't call the main program's init and fini functions 732 * for binaries linked with old crt1 which calls _init itself. 733 */ 734 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 735 obj_main->init_array = obj_main->fini_array = (Elf_Addr)NULL; 736 } 737 objlist_call_init(&initlist, &lockstate); 738 _r_debug_postinit(&obj_main->linkmap); 739 objlist_clear(&initlist); 740 dbg("loading filtees"); 741 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 742 if (ld_loadfltr || obj->z_loadfltr) 743 load_filtees(obj, 0, &lockstate); 744 } 745 lock_release(rtld_bind_lock, &lockstate); 746 } 747 748 void * 749 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 750 { 751 void *ptr; 752 Elf_Addr target; 753 754 ptr = (void *)make_function_pointer(def, obj); 755 target = ((Elf_Addr (*)(void))ptr)(); 756 return ((void *)target); 757 } 758 759 Elf_Addr 760 _rtld_bind(Obj_Entry *obj, Elf_Size reloff, void *stack) 761 { 762 const Elf_Rel *rel; 763 const Elf_Sym *def; 764 const Obj_Entry *defobj; 765 Elf_Addr *where; 766 Elf_Addr target; 767 RtldLockState lockstate; 768 769 rlock_acquire(rtld_bind_lock, &lockstate); 770 if (sigsetjmp(lockstate.env, 0) != 0) 771 lock_upgrade(rtld_bind_lock, &lockstate); 772 if (obj->pltrel) 773 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 774 else 775 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 776 777 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 778 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL, 779 &lockstate); 780 if (def == NULL) 781 die(); 782 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 783 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 784 else 785 target = (Elf_Addr)(defobj->relocbase + def->st_value); 786 787 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 788 defobj->strtab + def->st_name, basename(obj->path), 789 (void *)target, basename(defobj->path)); 790 791 /* 792 * If we have a function call tracing hook, and the 793 * hook would like to keep tracing this one function, 794 * prevent the relocation so we will wind up here 795 * the next time again. 796 * 797 * We don't want to functrace calls from the functracer 798 * to avoid recursive loops. 799 */ 800 if (rtld_functrace != NULL && obj != rtld_functrace_obj) { 801 if (rtld_functrace(obj->path, 802 defobj->path, 803 defobj->strtab + def->st_name, 804 stack)) { 805 lock_release(rtld_bind_lock, &lockstate); 806 return target; 807 } 808 } 809 810 /* 811 * Write the new contents for the jmpslot. Note that depending on 812 * architecture, the value which we need to return back to the 813 * lazy binding trampoline may or may not be the target 814 * address. The value returned from reloc_jmpslot() is the value 815 * that the trampoline needs. 816 */ 817 target = reloc_jmpslot(where, target, defobj, obj, rel); 818 lock_release(rtld_bind_lock, &lockstate); 819 return target; 820 } 821 822 /* 823 * Error reporting function. Use it like printf. If formats the message 824 * into a buffer, and sets things up so that the next call to dlerror() 825 * will return the message. 826 */ 827 void 828 _rtld_error(const char *fmt, ...) 829 { 830 static char buf[512]; 831 va_list ap; 832 833 va_start(ap, fmt); 834 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 835 error_message = buf; 836 va_end(ap); 837 } 838 839 /* 840 * Return a dynamically-allocated copy of the current error message, if any. 841 */ 842 static char * 843 errmsg_save(void) 844 { 845 return error_message == NULL ? NULL : xstrdup(error_message); 846 } 847 848 /* 849 * Restore the current error message from a copy which was previously saved 850 * by errmsg_save(). The copy is freed. 851 */ 852 static void 853 errmsg_restore(char *saved_msg) 854 { 855 if (saved_msg == NULL) 856 error_message = NULL; 857 else { 858 _rtld_error("%s", saved_msg); 859 free(saved_msg); 860 } 861 } 862 863 const char * 864 basename(const char *name) 865 { 866 const char *p = strrchr(name, '/'); 867 return p != NULL ? p + 1 : name; 868 } 869 870 static struct utsname uts; 871 872 static char * 873 origin_subst_one(char *real, const char *kw, const char *subst, 874 bool may_free) 875 { 876 char *p, *p1, *res, *resp; 877 int subst_len, kw_len, subst_count, old_len, new_len; 878 879 kw_len = strlen(kw); 880 881 /* 882 * First, count the number of the keyword occurrences, to 883 * preallocate the final string. 884 */ 885 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 886 p1 = strstr(p, kw); 887 if (p1 == NULL) 888 break; 889 } 890 891 /* 892 * If the keyword is not found, just return. 893 */ 894 if (subst_count == 0) 895 return (may_free ? real : xstrdup(real)); 896 897 /* 898 * There is indeed something to substitute. Calculate the 899 * length of the resulting string, and allocate it. 900 */ 901 subst_len = strlen(subst); 902 old_len = strlen(real); 903 new_len = old_len + (subst_len - kw_len) * subst_count; 904 res = xmalloc(new_len + 1); 905 906 /* 907 * Now, execute the substitution loop. 908 */ 909 for (p = real, resp = res, *resp = '\0';;) { 910 p1 = strstr(p, kw); 911 if (p1 != NULL) { 912 /* Copy the prefix before keyword. */ 913 memcpy(resp, p, p1 - p); 914 resp += p1 - p; 915 /* Keyword replacement. */ 916 memcpy(resp, subst, subst_len); 917 resp += subst_len; 918 *resp = '\0'; 919 p = p1 + kw_len; 920 } else 921 break; 922 } 923 924 /* Copy to the end of string and finish. */ 925 strcat(resp, p); 926 if (may_free) 927 free(real); 928 return (res); 929 } 930 931 static char * 932 origin_subst(char *real, const char *origin_path) 933 { 934 char *res1, *res2, *res3, *res4; 935 936 if (uts.sysname[0] == '\0') { 937 if (uname(&uts) != 0) { 938 _rtld_error("utsname failed: %d", errno); 939 return (NULL); 940 } 941 } 942 res1 = origin_subst_one(real, "$ORIGIN", origin_path, false); 943 res2 = origin_subst_one(res1, "$OSNAME", uts.sysname, true); 944 res3 = origin_subst_one(res2, "$OSREL", uts.release, true); 945 res4 = origin_subst_one(res3, "$PLATFORM", uts.machine, true); 946 return (res4); 947 } 948 949 static void 950 die(void) 951 { 952 const char *msg = dlerror(); 953 954 if (msg == NULL) 955 msg = "Fatal error"; 956 rtld_fdputstr(STDERR_FILENO, msg); 957 rtld_fdputchar(STDERR_FILENO, '\n'); 958 _exit(1); 959 } 960 961 /* 962 * Process a shared object's DYNAMIC section, and save the important 963 * information in its Obj_Entry structure. 964 */ 965 static void 966 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 967 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 968 { 969 const Elf_Dyn *dynp; 970 Needed_Entry **needed_tail = &obj->needed; 971 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 972 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 973 const Elf_Hashelt *hashtab; 974 const Elf32_Word *hashval; 975 Elf32_Word bkt, nmaskwords; 976 int bloom_size32; 977 bool nmw_power2; 978 int plttype = DT_REL; 979 980 *dyn_rpath = NULL; 981 *dyn_soname = NULL; 982 *dyn_runpath = NULL; 983 984 obj->bind_now = false; 985 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 986 switch (dynp->d_tag) { 987 988 case DT_REL: 989 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 990 break; 991 992 case DT_RELSZ: 993 obj->relsize = dynp->d_un.d_val; 994 break; 995 996 case DT_RELENT: 997 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 998 break; 999 1000 case DT_JMPREL: 1001 obj->pltrel = (const Elf_Rel *) 1002 (obj->relocbase + dynp->d_un.d_ptr); 1003 break; 1004 1005 case DT_PLTRELSZ: 1006 obj->pltrelsize = dynp->d_un.d_val; 1007 break; 1008 1009 case DT_RELA: 1010 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 1011 break; 1012 1013 case DT_RELASZ: 1014 obj->relasize = dynp->d_un.d_val; 1015 break; 1016 1017 case DT_RELAENT: 1018 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 1019 break; 1020 1021 case DT_PLTREL: 1022 plttype = dynp->d_un.d_val; 1023 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 1024 break; 1025 1026 case DT_SYMTAB: 1027 obj->symtab = (const Elf_Sym *) 1028 (obj->relocbase + dynp->d_un.d_ptr); 1029 break; 1030 1031 case DT_SYMENT: 1032 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 1033 break; 1034 1035 case DT_STRTAB: 1036 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 1037 break; 1038 1039 case DT_STRSZ: 1040 obj->strsize = dynp->d_un.d_val; 1041 break; 1042 1043 case DT_VERNEED: 1044 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 1045 dynp->d_un.d_val); 1046 break; 1047 1048 case DT_VERNEEDNUM: 1049 obj->verneednum = dynp->d_un.d_val; 1050 break; 1051 1052 case DT_VERDEF: 1053 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 1054 dynp->d_un.d_val); 1055 break; 1056 1057 case DT_VERDEFNUM: 1058 obj->verdefnum = dynp->d_un.d_val; 1059 break; 1060 1061 case DT_VERSYM: 1062 obj->versyms = (const Elf_Versym *)(obj->relocbase + 1063 dynp->d_un.d_val); 1064 break; 1065 1066 case DT_HASH: 1067 { 1068 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1069 dynp->d_un.d_ptr); 1070 obj->nbuckets = hashtab[0]; 1071 obj->nchains = hashtab[1]; 1072 obj->buckets = hashtab + 2; 1073 obj->chains = obj->buckets + obj->nbuckets; 1074 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 1075 obj->buckets != NULL; 1076 } 1077 break; 1078 1079 case DT_GNU_HASH: 1080 { 1081 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1082 dynp->d_un.d_ptr); 1083 obj->nbuckets_gnu = hashtab[0]; 1084 obj->symndx_gnu = hashtab[1]; 1085 nmaskwords = hashtab[2]; 1086 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1087 /* Number of bitmask words is required to be power of 2 */ 1088 nmw_power2 = ((nmaskwords & (nmaskwords - 1)) == 0); 1089 obj->maskwords_bm_gnu = nmaskwords - 1; 1090 obj->shift2_gnu = hashtab[3]; 1091 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4); 1092 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1093 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1094 obj->symndx_gnu; 1095 obj->valid_hash_gnu = nmw_power2 && obj->nbuckets_gnu > 0 && 1096 obj->buckets_gnu != NULL; 1097 } 1098 break; 1099 1100 case DT_NEEDED: 1101 if (!obj->rtld) { 1102 Needed_Entry *nep = NEW(Needed_Entry); 1103 nep->name = dynp->d_un.d_val; 1104 nep->obj = NULL; 1105 nep->next = NULL; 1106 1107 *needed_tail = nep; 1108 needed_tail = &nep->next; 1109 } 1110 break; 1111 1112 case DT_FILTER: 1113 if (!obj->rtld) { 1114 Needed_Entry *nep = NEW(Needed_Entry); 1115 nep->name = dynp->d_un.d_val; 1116 nep->obj = NULL; 1117 nep->next = NULL; 1118 1119 *needed_filtees_tail = nep; 1120 needed_filtees_tail = &nep->next; 1121 } 1122 break; 1123 1124 case DT_AUXILIARY: 1125 if (!obj->rtld) { 1126 Needed_Entry *nep = NEW(Needed_Entry); 1127 nep->name = dynp->d_un.d_val; 1128 nep->obj = NULL; 1129 nep->next = NULL; 1130 1131 *needed_aux_filtees_tail = nep; 1132 needed_aux_filtees_tail = &nep->next; 1133 } 1134 break; 1135 1136 case DT_PLTGOT: 1137 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 1138 break; 1139 1140 case DT_TEXTREL: 1141 obj->textrel = true; 1142 break; 1143 1144 case DT_SYMBOLIC: 1145 obj->symbolic = true; 1146 break; 1147 1148 case DT_RPATH: 1149 /* 1150 * We have to wait until later to process this, because we 1151 * might not have gotten the address of the string table yet. 1152 */ 1153 *dyn_rpath = dynp; 1154 break; 1155 1156 case DT_SONAME: 1157 *dyn_soname = dynp; 1158 break; 1159 1160 case DT_RUNPATH: 1161 *dyn_runpath = dynp; 1162 break; 1163 1164 case DT_INIT: 1165 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1166 break; 1167 1168 case DT_PREINIT_ARRAY: 1169 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1170 break; 1171 1172 case DT_PREINIT_ARRAYSZ: 1173 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1174 break; 1175 1176 case DT_INIT_ARRAY: 1177 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1178 break; 1179 1180 case DT_INIT_ARRAYSZ: 1181 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1182 break; 1183 1184 case DT_FINI: 1185 obj->fini = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1186 break; 1187 1188 case DT_FINI_ARRAY: 1189 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1190 break; 1191 1192 case DT_FINI_ARRAYSZ: 1193 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1194 break; 1195 1196 case DT_DEBUG: 1197 /* XXX - not implemented yet */ 1198 if (!early) 1199 dbg("Filling in DT_DEBUG entry"); 1200 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 1201 break; 1202 1203 case DT_FLAGS: 1204 if ((dynp->d_un.d_val & DF_ORIGIN) && trust) 1205 obj->z_origin = true; 1206 if (dynp->d_un.d_val & DF_SYMBOLIC) 1207 obj->symbolic = true; 1208 if (dynp->d_un.d_val & DF_TEXTREL) 1209 obj->textrel = true; 1210 if (dynp->d_un.d_val & DF_BIND_NOW) 1211 obj->bind_now = true; 1212 /*if (dynp->d_un.d_val & DF_STATIC_TLS) 1213 ;*/ 1214 break; 1215 1216 case DT_FLAGS_1: 1217 if (dynp->d_un.d_val & DF_1_NOOPEN) 1218 obj->z_noopen = true; 1219 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust) 1220 obj->z_origin = true; 1221 /*if (dynp->d_un.d_val & DF_1_GLOBAL) 1222 XXX ;*/ 1223 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1224 obj->bind_now = true; 1225 if (dynp->d_un.d_val & DF_1_NODELETE) 1226 obj->z_nodelete = true; 1227 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1228 obj->z_loadfltr = true; 1229 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1230 obj->z_interpose = true; 1231 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1232 obj->z_nodeflib = true; 1233 break; 1234 1235 default: 1236 if (!early) { 1237 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1238 (long)dynp->d_tag); 1239 } 1240 break; 1241 } 1242 } 1243 1244 obj->traced = false; 1245 1246 if (plttype == DT_RELA) { 1247 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1248 obj->pltrel = NULL; 1249 obj->pltrelasize = obj->pltrelsize; 1250 obj->pltrelsize = 0; 1251 } 1252 1253 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1254 if (obj->valid_hash_sysv) 1255 obj->dynsymcount = obj->nchains; 1256 else if (obj->valid_hash_gnu) { 1257 obj->dynsymcount = 0; 1258 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1259 if (obj->buckets_gnu[bkt] == 0) 1260 continue; 1261 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1262 do 1263 obj->dynsymcount++; 1264 while ((*hashval++ & 1u) == 0); 1265 } 1266 obj->dynsymcount += obj->symndx_gnu; 1267 } 1268 } 1269 1270 static void 1271 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1272 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1273 { 1274 1275 if (obj->z_origin && obj->origin_path == NULL) { 1276 obj->origin_path = xmalloc(PATH_MAX); 1277 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1) 1278 die(); 1279 } 1280 1281 if (dyn_runpath != NULL) { 1282 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val; 1283 if (obj->z_origin) 1284 obj->runpath = origin_subst(obj->runpath, obj->origin_path); 1285 } 1286 else if (dyn_rpath != NULL) { 1287 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 1288 if (obj->z_origin) 1289 obj->rpath = origin_subst(obj->rpath, obj->origin_path); 1290 } 1291 1292 if (dyn_soname != NULL) 1293 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1294 } 1295 1296 static void 1297 digest_dynamic(Obj_Entry *obj, int early) 1298 { 1299 const Elf_Dyn *dyn_rpath; 1300 const Elf_Dyn *dyn_soname; 1301 const Elf_Dyn *dyn_runpath; 1302 1303 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1304 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath); 1305 } 1306 1307 /* 1308 * Process a shared object's program header. This is used only for the 1309 * main program, when the kernel has already loaded the main program 1310 * into memory before calling the dynamic linker. It creates and 1311 * returns an Obj_Entry structure. 1312 */ 1313 static Obj_Entry * 1314 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1315 { 1316 Obj_Entry *obj; 1317 const Elf_Phdr *phlimit = phdr + phnum; 1318 const Elf_Phdr *ph; 1319 Elf_Addr note_start, note_end; 1320 int nsegs = 0; 1321 1322 obj = obj_new(); 1323 for (ph = phdr; ph < phlimit; ph++) { 1324 if (ph->p_type != PT_PHDR) 1325 continue; 1326 1327 obj->phdr = phdr; 1328 obj->phsize = ph->p_memsz; 1329 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1330 break; 1331 } 1332 1333 obj->stack_flags = PF_X | PF_R | PF_W; 1334 1335 for (ph = phdr; ph < phlimit; ph++) { 1336 switch (ph->p_type) { 1337 1338 case PT_INTERP: 1339 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1340 break; 1341 1342 case PT_LOAD: 1343 if (nsegs == 0) { /* First load segment */ 1344 obj->vaddrbase = trunc_page(ph->p_vaddr); 1345 obj->mapbase = obj->vaddrbase + obj->relocbase; 1346 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1347 obj->vaddrbase; 1348 } else { /* Last load segment */ 1349 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1350 obj->vaddrbase; 1351 } 1352 nsegs++; 1353 break; 1354 1355 case PT_DYNAMIC: 1356 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1357 break; 1358 1359 case PT_TLS: 1360 obj->tlsindex = 1; 1361 obj->tlssize = ph->p_memsz; 1362 obj->tlsalign = ph->p_align; 1363 obj->tlsinitsize = ph->p_filesz; 1364 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1365 break; 1366 1367 case PT_GNU_STACK: 1368 obj->stack_flags = ph->p_flags; 1369 break; 1370 1371 case PT_GNU_RELRO: 1372 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1373 obj->relro_size = round_page(ph->p_memsz); 1374 break; 1375 1376 case PT_NOTE: 1377 obj->note_present = true; 1378 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1379 note_end = note_start + ph->p_filesz; 1380 digest_notes(obj, note_start, note_end); 1381 break; 1382 } 1383 } 1384 if (nsegs < 1) { 1385 _rtld_error("%s: too few PT_LOAD segments", path); 1386 return NULL; 1387 } 1388 1389 obj->entry = entry; 1390 return obj; 1391 } 1392 1393 void 1394 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1395 { 1396 const Elf_Note *note; 1397 const char *note_name; 1398 uintptr_t p; 1399 1400 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1401 note = (const Elf_Note *)((const char *)(note + 1) + 1402 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1403 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1404 if (note->n_namesz != sizeof(NOTE_VENDOR) || 1405 note->n_descsz != sizeof(int32_t)) 1406 continue; 1407 if (note->n_type != ABI_NOTETYPE && 1408 note->n_type != CRT_NOINIT_NOTETYPE) 1409 continue; 1410 note_name = (const char *)(note + 1); 1411 if (strncmp(NOTE_VENDOR, note_name, sizeof(NOTE_VENDOR)) != 0) 1412 continue; 1413 switch (note->n_type) { 1414 case ABI_NOTETYPE: 1415 /* DragonFly osrel note */ 1416 p = (uintptr_t)(note + 1); 1417 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1418 obj->osrel = *(const int32_t *)(p); 1419 dbg("note osrel %d", obj->osrel); 1420 break; 1421 case CRT_NOINIT_NOTETYPE: 1422 /* DragonFly 'crt does not call init' note */ 1423 obj->crt_no_init = true; 1424 dbg("note crt_no_init"); 1425 break; 1426 } 1427 } 1428 } 1429 1430 static Obj_Entry * 1431 dlcheck(void *handle) 1432 { 1433 Obj_Entry *obj; 1434 1435 for (obj = obj_list; obj != NULL; obj = obj->next) 1436 if (obj == (Obj_Entry *) handle) 1437 break; 1438 1439 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1440 _rtld_error("Invalid shared object handle %p", handle); 1441 return NULL; 1442 } 1443 return obj; 1444 } 1445 1446 /* 1447 * If the given object is already in the donelist, return true. Otherwise 1448 * add the object to the list and return false. 1449 */ 1450 static bool 1451 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1452 { 1453 unsigned int i; 1454 1455 for (i = 0; i < dlp->num_used; i++) 1456 if (dlp->objs[i] == obj) 1457 return true; 1458 /* 1459 * Our donelist allocation should always be sufficient. But if 1460 * our threads locking isn't working properly, more shared objects 1461 * could have been loaded since we allocated the list. That should 1462 * never happen, but we'll handle it properly just in case it does. 1463 */ 1464 if (dlp->num_used < dlp->num_alloc) 1465 dlp->objs[dlp->num_used++] = obj; 1466 return false; 1467 } 1468 1469 /* 1470 * Hash function for symbol table lookup. Don't even think about changing 1471 * this. It is specified by the System V ABI. 1472 */ 1473 unsigned long 1474 elf_hash(const char *name) 1475 { 1476 const unsigned char *p = (const unsigned char *) name; 1477 unsigned long h = 0; 1478 unsigned long g; 1479 1480 while (*p != '\0') { 1481 h = (h << 4) + *p++; 1482 if ((g = h & 0xf0000000) != 0) 1483 h ^= g >> 24; 1484 h &= ~g; 1485 } 1486 return h; 1487 } 1488 1489 /* 1490 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1491 * unsigned in case it's implemented with a wider type. 1492 */ 1493 static uint_fast32_t 1494 gnu_hash(const char *s) 1495 { 1496 uint_fast32_t h; 1497 unsigned char c; 1498 1499 h = 5381; 1500 for (c = *s; c != '\0'; c = *++s) 1501 h = h * 33 + c; 1502 return (h & 0xffffffff); 1503 } 1504 1505 1506 /* 1507 * Find the library with the given name, and return its full pathname. 1508 * The returned string is dynamically allocated. Generates an error 1509 * message and returns NULL if the library cannot be found. 1510 * 1511 * If the second argument is non-NULL, then it refers to an already- 1512 * loaded shared object, whose library search path will be searched. 1513 * 1514 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1515 * descriptor (which is close-on-exec) will be passed out via the third 1516 * argument. 1517 * 1518 * The search order is: 1519 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1520 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1521 * LD_LIBRARY_PATH 1522 * DT_RUNPATH in the referencing file 1523 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1524 * from list) 1525 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1526 * 1527 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1528 */ 1529 static char * 1530 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1531 { 1532 char *pathname; 1533 char *name; 1534 bool nodeflib, objgiven; 1535 1536 objgiven = refobj != NULL; 1537 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */ 1538 if (xname[0] != '/' && !trust) { 1539 _rtld_error("Absolute pathname required for shared object \"%s\"", 1540 xname); 1541 return NULL; 1542 } 1543 if (objgiven && refobj->z_origin) { 1544 return (origin_subst(__DECONST(char *, xname), 1545 refobj->origin_path)); 1546 } else { 1547 return (xstrdup(xname)); 1548 } 1549 } 1550 1551 if (libmap_disable || !objgiven || 1552 (name = lm_find(refobj->path, xname)) == NULL) 1553 name = (char *)xname; 1554 1555 dbg(" Searching for \"%s\"", name); 1556 1557 nodeflib = objgiven ? refobj->z_nodeflib : false; 1558 if ((objgiven && 1559 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1560 (objgiven && refobj->runpath == NULL && refobj != obj_main && 1561 (pathname = search_library_path(name, obj_main->rpath)) != NULL) || 1562 (pathname = search_library_path(name, ld_library_path)) != NULL || 1563 (objgiven && 1564 (pathname = search_library_path(name, refobj->runpath)) != NULL) || 1565 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL || 1566 (pathname = search_library_path(name, gethints(nodeflib))) != NULL || 1567 (objgiven && !nodeflib && 1568 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)) 1569 return (pathname); 1570 1571 if (objgiven && refobj->path != NULL) { 1572 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 1573 name, basename(refobj->path)); 1574 } else { 1575 _rtld_error("Shared object \"%s\" not found", name); 1576 } 1577 return NULL; 1578 } 1579 1580 /* 1581 * Given a symbol number in a referencing object, find the corresponding 1582 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1583 * no definition was found. Returns a pointer to the Obj_Entry of the 1584 * defining object via the reference parameter DEFOBJ_OUT. 1585 */ 1586 const Elf_Sym * 1587 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1588 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1589 RtldLockState *lockstate) 1590 { 1591 const Elf_Sym *ref; 1592 const Elf_Sym *def; 1593 const Obj_Entry *defobj; 1594 SymLook req; 1595 const char *name; 1596 int res; 1597 1598 /* 1599 * If we have already found this symbol, get the information from 1600 * the cache. 1601 */ 1602 if (symnum >= refobj->dynsymcount) 1603 return NULL; /* Bad object */ 1604 if (cache != NULL && cache[symnum].sym != NULL) { 1605 *defobj_out = cache[symnum].obj; 1606 return cache[symnum].sym; 1607 } 1608 1609 ref = refobj->symtab + symnum; 1610 name = refobj->strtab + ref->st_name; 1611 def = NULL; 1612 defobj = NULL; 1613 1614 /* 1615 * We don't have to do a full scale lookup if the symbol is local. 1616 * We know it will bind to the instance in this load module; to 1617 * which we already have a pointer (ie ref). By not doing a lookup, 1618 * we not only improve performance, but it also avoids unresolvable 1619 * symbols when local symbols are not in the hash table. 1620 * 1621 * This might occur for TLS module relocations, which simply use 1622 * symbol 0. 1623 */ 1624 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1625 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1626 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1627 symnum); 1628 } 1629 symlook_init(&req, name); 1630 req.flags = flags; 1631 req.ventry = fetch_ventry(refobj, symnum); 1632 req.lockstate = lockstate; 1633 res = symlook_default(&req, refobj); 1634 if (res == 0) { 1635 def = req.sym_out; 1636 defobj = req.defobj_out; 1637 } 1638 } else { 1639 def = ref; 1640 defobj = refobj; 1641 } 1642 1643 /* 1644 * If we found no definition and the reference is weak, treat the 1645 * symbol as having the value zero. 1646 */ 1647 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1648 def = &sym_zero; 1649 defobj = obj_main; 1650 } 1651 1652 if (def != NULL) { 1653 *defobj_out = defobj; 1654 /* Record the information in the cache to avoid subsequent lookups. */ 1655 if (cache != NULL) { 1656 cache[symnum].sym = def; 1657 cache[symnum].obj = defobj; 1658 } 1659 } else { 1660 if (refobj != &obj_rtld) 1661 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name); 1662 } 1663 return def; 1664 } 1665 1666 /* 1667 * Return the search path from the ldconfig hints file, reading it if 1668 * necessary. If nostdlib is true, then the default search paths are 1669 * not added to result. 1670 * 1671 * Returns NULL if there are problems with the hints file, 1672 * or if the search path there is empty. 1673 */ 1674 static const char * 1675 gethints(bool nostdlib) 1676 { 1677 static char *hints, *filtered_path; 1678 struct elfhints_hdr hdr; 1679 struct fill_search_info_args sargs, hargs; 1680 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1681 struct dl_serpath *SLPpath, *hintpath; 1682 char *p; 1683 unsigned int SLPndx, hintndx, fndx, fcount; 1684 int fd; 1685 size_t flen; 1686 bool skip; 1687 1688 /* First call, read the hints file */ 1689 if (hints == NULL) { 1690 /* Keep from trying again in case the hints file is bad. */ 1691 hints = ""; 1692 1693 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1694 return (NULL); 1695 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1696 hdr.magic != ELFHINTS_MAGIC || 1697 hdr.version != 1) { 1698 close(fd); 1699 return (NULL); 1700 } 1701 p = xmalloc(hdr.dirlistlen + 1); 1702 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1703 read(fd, p, hdr.dirlistlen + 1) != 1704 (ssize_t)hdr.dirlistlen + 1) { 1705 free(p); 1706 close(fd); 1707 return (NULL); 1708 } 1709 hints = p; 1710 close(fd); 1711 } 1712 1713 /* 1714 * If caller agreed to receive list which includes the default 1715 * paths, we are done. Otherwise, if we still have not 1716 * calculated filtered result, do it now. 1717 */ 1718 if (!nostdlib) 1719 return (hints[0] != '\0' ? hints : NULL); 1720 if (filtered_path != NULL) 1721 goto filt_ret; 1722 1723 /* 1724 * Obtain the list of all configured search paths, and the 1725 * list of the default paths. 1726 * 1727 * First estimate the size of the results. 1728 */ 1729 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1730 smeta.dls_cnt = 0; 1731 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1732 hmeta.dls_cnt = 0; 1733 1734 sargs.request = RTLD_DI_SERINFOSIZE; 1735 sargs.serinfo = &smeta; 1736 hargs.request = RTLD_DI_SERINFOSIZE; 1737 hargs.serinfo = &hmeta; 1738 1739 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1740 path_enumerate(p, fill_search_info, &hargs); 1741 1742 SLPinfo = xmalloc(smeta.dls_size); 1743 hintinfo = xmalloc(hmeta.dls_size); 1744 1745 /* 1746 * Next fetch both sets of paths. 1747 */ 1748 sargs.request = RTLD_DI_SERINFO; 1749 sargs.serinfo = SLPinfo; 1750 sargs.serpath = &SLPinfo->dls_serpath[0]; 1751 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1752 1753 hargs.request = RTLD_DI_SERINFO; 1754 hargs.serinfo = hintinfo; 1755 hargs.serpath = &hintinfo->dls_serpath[0]; 1756 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1757 1758 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1759 path_enumerate(p, fill_search_info, &hargs); 1760 1761 /* 1762 * Now calculate the difference between two sets, by excluding 1763 * standard paths from the full set. 1764 */ 1765 fndx = 0; 1766 fcount = 0; 1767 filtered_path = xmalloc(hdr.dirlistlen + 1); 1768 hintpath = &hintinfo->dls_serpath[0]; 1769 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1770 skip = false; 1771 SLPpath = &SLPinfo->dls_serpath[0]; 1772 /* 1773 * Check each standard path against current. 1774 */ 1775 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1776 /* matched, skip the path */ 1777 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1778 skip = true; 1779 break; 1780 } 1781 } 1782 if (skip) 1783 continue; 1784 /* 1785 * Not matched against any standard path, add the path 1786 * to result. Separate consecutive paths with ':'. 1787 */ 1788 if (fcount > 0) { 1789 filtered_path[fndx] = ':'; 1790 fndx++; 1791 } 1792 fcount++; 1793 flen = strlen(hintpath->dls_name); 1794 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1795 fndx += flen; 1796 } 1797 filtered_path[fndx] = '\0'; 1798 1799 free(SLPinfo); 1800 free(hintinfo); 1801 1802 filt_ret: 1803 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1804 } 1805 1806 static void 1807 init_dag(Obj_Entry *root) 1808 { 1809 const Needed_Entry *needed; 1810 const Objlist_Entry *elm; 1811 DoneList donelist; 1812 1813 if (root->dag_inited) 1814 return; 1815 donelist_init(&donelist); 1816 1817 /* Root object belongs to own DAG. */ 1818 objlist_push_tail(&root->dldags, root); 1819 objlist_push_tail(&root->dagmembers, root); 1820 donelist_check(&donelist, root); 1821 1822 /* 1823 * Add dependencies of root object to DAG in breadth order 1824 * by exploiting the fact that each new object get added 1825 * to the tail of the dagmembers list. 1826 */ 1827 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1828 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1829 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1830 continue; 1831 objlist_push_tail(&needed->obj->dldags, root); 1832 objlist_push_tail(&root->dagmembers, needed->obj); 1833 } 1834 } 1835 root->dag_inited = true; 1836 } 1837 1838 static void 1839 process_nodelete(Obj_Entry *root) 1840 { 1841 const Objlist_Entry *elm; 1842 1843 /* 1844 * Walk over object DAG and process every dependent object that 1845 * is marked as DF_1_NODELETE. They need to grow their own DAG, 1846 * which then should have its reference upped separately. 1847 */ 1848 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1849 if (elm->obj != NULL && elm->obj->z_nodelete && 1850 !elm->obj->ref_nodel) { 1851 dbg("obj %s nodelete", elm->obj->path); 1852 init_dag(elm->obj); 1853 ref_dag(elm->obj); 1854 elm->obj->ref_nodel = true; 1855 } 1856 } 1857 } 1858 1859 /* 1860 * Initialize the dynamic linker. The argument is the address at which 1861 * the dynamic linker has been mapped into memory. The primary task of 1862 * this function is to relocate the dynamic linker. 1863 */ 1864 static void 1865 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 1866 { 1867 Obj_Entry objtmp; /* Temporary rtld object */ 1868 const Elf_Ehdr *ehdr; 1869 const Elf_Dyn *dyn_rpath; 1870 const Elf_Dyn *dyn_soname; 1871 const Elf_Dyn *dyn_runpath; 1872 1873 /* 1874 * Conjure up an Obj_Entry structure for the dynamic linker. 1875 * 1876 * The "path" member can't be initialized yet because string constants 1877 * cannot yet be accessed. Below we will set it correctly. 1878 */ 1879 memset(&objtmp, 0, sizeof(objtmp)); 1880 objtmp.path = NULL; 1881 objtmp.rtld = true; 1882 objtmp.mapbase = mapbase; 1883 #ifdef PIC 1884 objtmp.relocbase = mapbase; 1885 #endif 1886 if (RTLD_IS_DYNAMIC()) { 1887 objtmp.dynamic = rtld_dynamic(&objtmp); 1888 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 1889 assert(objtmp.needed == NULL); 1890 assert(!objtmp.textrel); 1891 1892 /* 1893 * Temporarily put the dynamic linker entry into the object list, so 1894 * that symbols can be found. 1895 */ 1896 1897 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 1898 } 1899 ehdr = (Elf_Ehdr *)mapbase; 1900 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 1901 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 1902 1903 /* Initialize the object list. */ 1904 obj_tail = &obj_list; 1905 1906 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1907 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1908 1909 #ifdef ENABLE_OSRELDATE 1910 if (aux_info[AT_OSRELDATE] != NULL) 1911 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 1912 #endif 1913 1914 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 1915 1916 /* Replace the path with a dynamically allocated copy. */ 1917 obj_rtld.path = xstrdup(PATH_RTLD); 1918 1919 r_debug.r_brk = r_debug_state; 1920 r_debug.r_state = RT_CONSISTENT; 1921 } 1922 1923 /* 1924 * Add the init functions from a needed object list (and its recursive 1925 * needed objects) to "list". This is not used directly; it is a helper 1926 * function for initlist_add_objects(). The write lock must be held 1927 * when this function is called. 1928 */ 1929 static void 1930 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 1931 { 1932 /* Recursively process the successor needed objects. */ 1933 if (needed->next != NULL) 1934 initlist_add_neededs(needed->next, list); 1935 1936 /* Process the current needed object. */ 1937 if (needed->obj != NULL) 1938 initlist_add_objects(needed->obj, &needed->obj->next, list); 1939 } 1940 1941 /* 1942 * Scan all of the DAGs rooted in the range of objects from "obj" to 1943 * "tail" and add their init functions to "list". This recurses over 1944 * the DAGs and ensure the proper init ordering such that each object's 1945 * needed libraries are initialized before the object itself. At the 1946 * same time, this function adds the objects to the global finalization 1947 * list "list_fini" in the opposite order. The write lock must be 1948 * held when this function is called. 1949 */ 1950 static void 1951 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list) 1952 { 1953 1954 if (obj->init_scanned || obj->init_done) 1955 return; 1956 obj->init_scanned = true; 1957 1958 /* Recursively process the successor objects. */ 1959 if (&obj->next != tail) 1960 initlist_add_objects(obj->next, tail, list); 1961 1962 /* Recursively process the needed objects. */ 1963 if (obj->needed != NULL) 1964 initlist_add_neededs(obj->needed, list); 1965 if (obj->needed_filtees != NULL) 1966 initlist_add_neededs(obj->needed_filtees, list); 1967 if (obj->needed_aux_filtees != NULL) 1968 initlist_add_neededs(obj->needed_aux_filtees, list); 1969 1970 /* Add the object to the init list. */ 1971 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL || 1972 obj->init_array != (Elf_Addr)NULL) 1973 objlist_push_tail(list, obj); 1974 1975 /* Add the object to the global fini list in the reverse order. */ 1976 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 1977 && !obj->on_fini_list) { 1978 objlist_push_head(&list_fini, obj); 1979 obj->on_fini_list = true; 1980 } 1981 } 1982 1983 #ifndef FPTR_TARGET 1984 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 1985 #endif 1986 1987 static void 1988 free_needed_filtees(Needed_Entry *n) 1989 { 1990 Needed_Entry *needed, *needed1; 1991 1992 for (needed = n; needed != NULL; needed = needed->next) { 1993 if (needed->obj != NULL) { 1994 dlclose(needed->obj); 1995 needed->obj = NULL; 1996 } 1997 } 1998 for (needed = n; needed != NULL; needed = needed1) { 1999 needed1 = needed->next; 2000 free(needed); 2001 } 2002 } 2003 2004 static void 2005 unload_filtees(Obj_Entry *obj) 2006 { 2007 2008 free_needed_filtees(obj->needed_filtees); 2009 obj->needed_filtees = NULL; 2010 free_needed_filtees(obj->needed_aux_filtees); 2011 obj->needed_aux_filtees = NULL; 2012 obj->filtees_loaded = false; 2013 } 2014 2015 static void 2016 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2017 RtldLockState *lockstate) 2018 { 2019 2020 for (; needed != NULL; needed = needed->next) { 2021 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2022 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2023 RTLD_LOCAL, lockstate); 2024 } 2025 } 2026 2027 static void 2028 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2029 { 2030 2031 lock_restart_for_upgrade(lockstate); 2032 if (!obj->filtees_loaded) { 2033 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2034 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2035 obj->filtees_loaded = true; 2036 } 2037 } 2038 2039 static int 2040 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2041 { 2042 Obj_Entry *obj1; 2043 2044 for (; needed != NULL; needed = needed->next) { 2045 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2046 flags & ~RTLD_LO_NOLOAD); 2047 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2048 return (-1); 2049 } 2050 return (0); 2051 } 2052 2053 /* 2054 * Given a shared object, traverse its list of needed objects, and load 2055 * each of them. Returns 0 on success. Generates an error message and 2056 * returns -1 on failure. 2057 */ 2058 static int 2059 load_needed_objects(Obj_Entry *first, int flags) 2060 { 2061 Obj_Entry *obj; 2062 2063 for (obj = first; obj != NULL; obj = obj->next) { 2064 if (process_needed(obj, obj->needed, flags) == -1) 2065 return (-1); 2066 } 2067 return (0); 2068 } 2069 2070 static int 2071 load_preload_objects(void) 2072 { 2073 char *p = ld_preload; 2074 Obj_Entry *obj; 2075 static const char delim[] = " \t:;"; 2076 2077 if (p == NULL) 2078 return 0; 2079 2080 p += strspn(p, delim); 2081 while (*p != '\0') { 2082 size_t len = strcspn(p, delim); 2083 char savech; 2084 SymLook req; 2085 int res; 2086 2087 savech = p[len]; 2088 p[len] = '\0'; 2089 obj = load_object(p, -1, NULL, 0); 2090 if (obj == NULL) 2091 return -1; /* XXX - cleanup */ 2092 obj->z_interpose = true; 2093 p[len] = savech; 2094 p += len; 2095 p += strspn(p, delim); 2096 2097 /* Check for the magic tracing function */ 2098 symlook_init(&req, RTLD_FUNCTRACE); 2099 res = symlook_obj(&req, obj); 2100 if (res == 0) { 2101 rtld_functrace = (void *)(req.defobj_out->relocbase + 2102 req.sym_out->st_value); 2103 rtld_functrace_obj = req.defobj_out; 2104 } 2105 } 2106 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2107 return 0; 2108 } 2109 2110 static const char * 2111 printable_path(const char *path) 2112 { 2113 2114 return (path == NULL ? "<unknown>" : path); 2115 } 2116 2117 /* 2118 * Load a shared object into memory, if it is not already loaded. The 2119 * object may be specified by name or by user-supplied file descriptor 2120 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2121 * duplicate is. 2122 * 2123 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2124 * on failure. 2125 */ 2126 static Obj_Entry * 2127 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2128 { 2129 Obj_Entry *obj; 2130 int fd; 2131 struct stat sb; 2132 char *path; 2133 2134 fd = -1; 2135 if (name != NULL) { 2136 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 2137 if (object_match_name(obj, name)) 2138 return (obj); 2139 } 2140 2141 path = find_library(name, refobj, &fd); 2142 if (path == NULL) 2143 return (NULL); 2144 } else 2145 path = NULL; 2146 2147 if (fd >= 0) { 2148 /* 2149 * search_library_pathfds() opens a fresh file descriptor for the 2150 * library, so there is no need to dup(). 2151 */ 2152 } else if (fd_u == -1) { 2153 /* 2154 * If we didn't find a match by pathname, or the name is not 2155 * supplied, open the file and check again by device and inode. 2156 * This avoids false mismatches caused by multiple links or ".." 2157 * in pathnames. 2158 * 2159 * To avoid a race, we open the file and use fstat() rather than 2160 * using stat(). 2161 */ 2162 if ((fd = open(path, O_RDONLY | O_CLOEXEC)) == -1) { 2163 _rtld_error("Cannot open \"%s\"", path); 2164 free(path); 2165 return (NULL); 2166 } 2167 } else { 2168 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2169 if (fd == -1) { 2170 _rtld_error("Cannot dup fd"); 2171 free(path); 2172 return (NULL); 2173 } 2174 } 2175 if (fstat(fd, &sb) == -1) { 2176 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2177 close(fd); 2178 free(path); 2179 return NULL; 2180 } 2181 for (obj = obj_list->next; obj != NULL; obj = obj->next) 2182 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2183 break; 2184 if (obj != NULL && name != NULL) { 2185 object_add_name(obj, name); 2186 free(path); 2187 close(fd); 2188 return obj; 2189 } 2190 if (flags & RTLD_LO_NOLOAD) { 2191 free(path); 2192 close(fd); 2193 return (NULL); 2194 } 2195 2196 /* First use of this object, so we must map it in */ 2197 obj = do_load_object(fd, name, path, &sb, flags); 2198 if (obj == NULL) 2199 free(path); 2200 close(fd); 2201 2202 return obj; 2203 } 2204 2205 static Obj_Entry * 2206 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2207 int flags) 2208 { 2209 Obj_Entry *obj; 2210 struct statfs fs; 2211 2212 /* 2213 * but first, make sure that environment variables haven't been 2214 * used to circumvent the noexec flag on a filesystem. 2215 */ 2216 if (dangerous_ld_env) { 2217 if (fstatfs(fd, &fs) != 0) { 2218 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2219 return NULL; 2220 } 2221 if (fs.f_flags & MNT_NOEXEC) { 2222 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 2223 return NULL; 2224 } 2225 } 2226 dbg("loading \"%s\"", printable_path(path)); 2227 obj = map_object(fd, printable_path(path), sbp); 2228 if (obj == NULL) 2229 return NULL; 2230 2231 /* 2232 * If DT_SONAME is present in the object, digest_dynamic2 already 2233 * added it to the object names. 2234 */ 2235 if (name != NULL) 2236 object_add_name(obj, name); 2237 obj->path = path; 2238 digest_dynamic(obj, 0); 2239 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2240 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2241 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2242 RTLD_LO_DLOPEN) { 2243 dbg("refusing to load non-loadable \"%s\"", obj->path); 2244 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2245 munmap(obj->mapbase, obj->mapsize); 2246 obj_free(obj); 2247 return (NULL); 2248 } 2249 2250 *obj_tail = obj; 2251 obj_tail = &obj->next; 2252 obj_count++; 2253 obj_loads++; 2254 linkmap_add(obj); /* for GDB & dlinfo() */ 2255 #if 0 2256 max_stack_flags |= obj->stack_flags; 2257 #endif 2258 2259 dbg(" %p .. %p: %s", obj->mapbase, 2260 obj->mapbase + obj->mapsize - 1, obj->path); 2261 if (obj->textrel) 2262 dbg(" WARNING: %s has impure text", obj->path); 2263 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2264 obj->path); 2265 2266 return obj; 2267 } 2268 2269 static Obj_Entry * 2270 obj_from_addr(const void *addr) 2271 { 2272 Obj_Entry *obj; 2273 2274 for (obj = obj_list; obj != NULL; obj = obj->next) { 2275 if (addr < (void *) obj->mapbase) 2276 continue; 2277 if (addr < (void *) (obj->mapbase + obj->mapsize)) 2278 return obj; 2279 } 2280 return NULL; 2281 } 2282 2283 /* 2284 * If the main program is defined with a .preinit_array section, call 2285 * each function in order. This must occur before the initialization 2286 * of any shared object or the main program. 2287 */ 2288 static void 2289 preinit_main(void) 2290 { 2291 Elf_Addr *preinit_addr; 2292 int index; 2293 2294 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2295 if (preinit_addr == NULL) 2296 return; 2297 2298 for (index = 0; index < obj_main->preinit_array_num; index++) { 2299 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2300 dbg("calling preinit function for %s at %p", obj_main->path, 2301 (void *)preinit_addr[index]); 2302 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2303 0, 0, obj_main->path); 2304 call_init_pointer(obj_main, preinit_addr[index]); 2305 } 2306 } 2307 } 2308 2309 /* 2310 * Call the finalization functions for each of the objects in "list" 2311 * belonging to the DAG of "root" and referenced once. If NULL "root" 2312 * is specified, every finalization function will be called regardless 2313 * of the reference count and the list elements won't be freed. All of 2314 * the objects are expected to have non-NULL fini functions. 2315 */ 2316 static void 2317 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2318 { 2319 Objlist_Entry *elm; 2320 char *saved_msg; 2321 Elf_Addr *fini_addr; 2322 int index; 2323 2324 assert(root == NULL || root->refcount == 1); 2325 2326 /* 2327 * Preserve the current error message since a fini function might 2328 * call into the dynamic linker and overwrite it. 2329 */ 2330 saved_msg = errmsg_save(); 2331 do { 2332 STAILQ_FOREACH(elm, list, link) { 2333 if (root != NULL && (elm->obj->refcount != 1 || 2334 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2335 continue; 2336 2337 /* Remove object from fini list to prevent recursive invocation. */ 2338 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2339 /* 2340 * XXX: If a dlopen() call references an object while the 2341 * fini function is in progress, we might end up trying to 2342 * unload the referenced object in dlclose() or the object 2343 * won't be unloaded although its fini function has been 2344 * called. 2345 */ 2346 lock_release(rtld_bind_lock, lockstate); 2347 2348 /* 2349 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2350 * When this happens, DT_FINI_ARRAY is processed first. 2351 * It is also processed backwards. It is possible to encounter 2352 * DT_FINI_ARRAY elements with values of 0 or 1, but they need 2353 * to be ignored. 2354 */ 2355 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2356 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2357 for (index = elm->obj->fini_array_num - 1; index >= 0; index--) { 2358 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2359 dbg("calling fini array function for %s at %p", 2360 elm->obj->path, (void *)fini_addr[index]); 2361 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2362 (void *)fini_addr[index], 0, 0, elm->obj->path); 2363 call_initfini_pointer(elm->obj, fini_addr[index]); 2364 } 2365 } 2366 } 2367 if (elm->obj->fini != (Elf_Addr)NULL) { 2368 dbg("calling fini function for %s at %p", elm->obj->path, 2369 (void *)elm->obj->fini); 2370 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2371 0, 0, elm->obj->path); 2372 call_initfini_pointer(elm->obj, elm->obj->fini); 2373 } 2374 wlock_acquire(rtld_bind_lock, lockstate); 2375 /* No need to free anything if process is going down. */ 2376 if (root != NULL) 2377 free(elm); 2378 /* 2379 * We must restart the list traversal after every fini call 2380 * because a dlclose() call from the fini function or from 2381 * another thread might have modified the reference counts. 2382 */ 2383 break; 2384 } 2385 } while (elm != NULL); 2386 errmsg_restore(saved_msg); 2387 } 2388 2389 /* 2390 * Call the initialization functions for each of the objects in 2391 * "list". All of the objects are expected to have non-NULL init 2392 * functions. 2393 */ 2394 static void 2395 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2396 { 2397 Objlist_Entry *elm; 2398 Obj_Entry *obj; 2399 char *saved_msg; 2400 Elf_Addr *init_addr; 2401 int index; 2402 2403 /* 2404 * Clean init_scanned flag so that objects can be rechecked and 2405 * possibly initialized earlier if any of vectors called below 2406 * cause the change by using dlopen. 2407 */ 2408 for (obj = obj_list; obj != NULL; obj = obj->next) 2409 obj->init_scanned = false; 2410 2411 /* 2412 * Preserve the current error message since an init function might 2413 * call into the dynamic linker and overwrite it. 2414 */ 2415 saved_msg = errmsg_save(); 2416 STAILQ_FOREACH(elm, list, link) { 2417 if (elm->obj->init_done) /* Initialized early. */ 2418 continue; 2419 2420 /* 2421 * Race: other thread might try to use this object before current 2422 * one completes the initilization. Not much can be done here 2423 * without better locking. 2424 */ 2425 elm->obj->init_done = true; 2426 lock_release(rtld_bind_lock, lockstate); 2427 2428 /* 2429 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2430 * When this happens, DT_INIT is processed first. 2431 * It is possible to encounter DT_INIT_ARRAY elements with values 2432 * of 0 or 1, but they need to be ignored. 2433 */ 2434 if (elm->obj->init != (Elf_Addr)NULL) { 2435 dbg("calling init function for %s at %p", elm->obj->path, 2436 (void *)elm->obj->init); 2437 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2438 0, 0, elm->obj->path); 2439 call_initfini_pointer(elm->obj, elm->obj->init); 2440 } 2441 init_addr = (Elf_Addr *)elm->obj->init_array; 2442 if (init_addr != NULL) { 2443 for (index = 0; index < elm->obj->init_array_num; index++) { 2444 if (init_addr[index] != 0 && init_addr[index] != 1) { 2445 dbg("calling init array function for %s at %p", elm->obj->path, 2446 (void *)init_addr[index]); 2447 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2448 (void *)init_addr[index], 0, 0, elm->obj->path); 2449 call_init_pointer(elm->obj, init_addr[index]); 2450 } 2451 } 2452 } 2453 wlock_acquire(rtld_bind_lock, lockstate); 2454 } 2455 errmsg_restore(saved_msg); 2456 } 2457 2458 static void 2459 objlist_clear(Objlist *list) 2460 { 2461 Objlist_Entry *elm; 2462 2463 while (!STAILQ_EMPTY(list)) { 2464 elm = STAILQ_FIRST(list); 2465 STAILQ_REMOVE_HEAD(list, link); 2466 free(elm); 2467 } 2468 } 2469 2470 static Objlist_Entry * 2471 objlist_find(Objlist *list, const Obj_Entry *obj) 2472 { 2473 Objlist_Entry *elm; 2474 2475 STAILQ_FOREACH(elm, list, link) 2476 if (elm->obj == obj) 2477 return elm; 2478 return NULL; 2479 } 2480 2481 static void 2482 objlist_init(Objlist *list) 2483 { 2484 STAILQ_INIT(list); 2485 } 2486 2487 static void 2488 objlist_push_head(Objlist *list, Obj_Entry *obj) 2489 { 2490 Objlist_Entry *elm; 2491 2492 elm = NEW(Objlist_Entry); 2493 elm->obj = obj; 2494 STAILQ_INSERT_HEAD(list, elm, link); 2495 } 2496 2497 static void 2498 objlist_push_tail(Objlist *list, Obj_Entry *obj) 2499 { 2500 Objlist_Entry *elm; 2501 2502 elm = NEW(Objlist_Entry); 2503 elm->obj = obj; 2504 STAILQ_INSERT_TAIL(list, elm, link); 2505 } 2506 2507 static void 2508 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2509 { 2510 Objlist_Entry *elm, *listelm; 2511 2512 STAILQ_FOREACH(listelm, list, link) { 2513 if (listelm->obj == listobj) 2514 break; 2515 } 2516 elm = NEW(Objlist_Entry); 2517 elm->obj = obj; 2518 if (listelm != NULL) 2519 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2520 else 2521 STAILQ_INSERT_TAIL(list, elm, link); 2522 } 2523 2524 static void 2525 objlist_remove(Objlist *list, Obj_Entry *obj) 2526 { 2527 Objlist_Entry *elm; 2528 2529 if ((elm = objlist_find(list, obj)) != NULL) { 2530 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2531 free(elm); 2532 } 2533 } 2534 2535 /* 2536 * Relocate dag rooted in the specified object. 2537 * Returns 0 on success, or -1 on failure. 2538 */ 2539 2540 static int 2541 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2542 int flags, RtldLockState *lockstate) 2543 { 2544 Objlist_Entry *elm; 2545 int error; 2546 2547 error = 0; 2548 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2549 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2550 lockstate); 2551 if (error == -1) 2552 break; 2553 } 2554 return (error); 2555 } 2556 2557 /* 2558 * Prepare for, or clean after, relocating an object marked with 2559 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 2560 * segments are remapped read-write. After relocations are done, the 2561 * segment's permissions are returned back to the modes specified in 2562 * the phdrs. If any relocation happened, or always for wired 2563 * program, COW is triggered. 2564 */ 2565 static int 2566 reloc_textrel_prot(Obj_Entry *obj, bool before) 2567 { 2568 const Elf_Phdr *ph; 2569 void *base; 2570 size_t l, sz; 2571 int prot; 2572 2573 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 2574 l--, ph++) { 2575 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 2576 continue; 2577 base = obj->relocbase + trunc_page(ph->p_vaddr); 2578 sz = round_page(ph->p_vaddr + ph->p_filesz) - 2579 trunc_page(ph->p_vaddr); 2580 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0); 2581 /* 2582 * Make sure modified text segments are included in the 2583 * core dump since we modified it. This unfortunately causes the 2584 * entire text segment to core-out but we don't have much of a 2585 * choice. We could try to only reenable core dumps on pages 2586 * in which relocations occured but that is likely most of the text 2587 * pages anyway, and even that would not work because the rest of 2588 * the text pages would wind up as a read-only OBJT_DEFAULT object 2589 * (created due to our modifications) backed by the original OBJT_VNODE 2590 * object, and the ELF coredump code is currently only able to dump 2591 * vnode records for pure vnode-backed mappings, not vnode backings 2592 * to memory objects. 2593 */ 2594 if (before == false) 2595 madvise(base, sz, MADV_CORE); 2596 if (mprotect(base, sz, prot) == -1) { 2597 _rtld_error("%s: Cannot write-%sable text segment: %s", 2598 obj->path, before ? "en" : "dis", 2599 rtld_strerror(errno)); 2600 return (-1); 2601 } 2602 } 2603 return (0); 2604 } 2605 2606 /* 2607 * Relocate single object. 2608 * Returns 0 on success, or -1 on failure. 2609 */ 2610 static int 2611 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2612 int flags, RtldLockState *lockstate) 2613 { 2614 2615 if (obj->relocated) 2616 return (0); 2617 obj->relocated = true; 2618 if (obj != rtldobj) 2619 dbg("relocating \"%s\"", obj->path); 2620 2621 if (obj->symtab == NULL || obj->strtab == NULL || 2622 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2623 _rtld_error("%s: Shared object has no run-time symbol table", 2624 obj->path); 2625 return (-1); 2626 } 2627 2628 /* There are relocations to the write-protected text segment. */ 2629 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 2630 return (-1); 2631 2632 /* Process the non-PLT non-IFUNC relocations. */ 2633 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2634 return (-1); 2635 2636 /* Re-protected the text segment. */ 2637 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 2638 return (-1); 2639 2640 /* Set the special PLT or GOT entries. */ 2641 init_pltgot(obj); 2642 2643 /* Process the PLT relocations. */ 2644 if (reloc_plt(obj) == -1) 2645 return (-1); 2646 /* Relocate the jump slots if we are doing immediate binding. */ 2647 if (obj->bind_now || bind_now) 2648 if (reloc_jmpslots(obj, flags, lockstate) == -1) 2649 return (-1); 2650 2651 /* 2652 * Process the non-PLT IFUNC relocations. The relocations are 2653 * processed in two phases, because IFUNC resolvers may 2654 * reference other symbols, which must be readily processed 2655 * before resolvers are called. 2656 */ 2657 if (obj->non_plt_gnu_ifunc && 2658 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate)) 2659 return (-1); 2660 2661 /* 2662 * Set up the magic number and version in the Obj_Entry. These 2663 * were checked in the crt1.o from the original ElfKit, so we 2664 * set them for backward compatibility. 2665 */ 2666 obj->magic = RTLD_MAGIC; 2667 obj->version = RTLD_VERSION; 2668 2669 /* 2670 * Set relocated data to read-only status if protection specified 2671 */ 2672 2673 if (obj->relro_size) { 2674 if (mprotect(obj->relro_page, obj->relro_size, PROT_READ) == -1) { 2675 _rtld_error("%s: Cannot enforce relro relocation: %s", 2676 obj->path, rtld_strerror(errno)); 2677 return (-1); 2678 } 2679 obj->relro_protected = true; 2680 } 2681 return (0); 2682 } 2683 2684 /* 2685 * Relocate newly-loaded shared objects. The argument is a pointer to 2686 * the Obj_Entry for the first such object. All objects from the first 2687 * to the end of the list of objects are relocated. Returns 0 on success, 2688 * or -1 on failure. 2689 */ 2690 static int 2691 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2692 int flags, RtldLockState *lockstate) 2693 { 2694 Obj_Entry *obj; 2695 int error; 2696 2697 for (error = 0, obj = first; obj != NULL; obj = obj->next) { 2698 error = relocate_object(obj, bind_now, rtldobj, flags, 2699 lockstate); 2700 if (error == -1) 2701 break; 2702 } 2703 return (error); 2704 } 2705 2706 /* 2707 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2708 * referencing STT_GNU_IFUNC symbols is postponed till the other 2709 * relocations are done. The indirect functions specified as 2710 * ifunc are allowed to call other symbols, so we need to have 2711 * objects relocated before asking for resolution from indirects. 2712 * 2713 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2714 * instead of the usual lazy handling of PLT slots. It is 2715 * consistent with how GNU does it. 2716 */ 2717 static int 2718 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2719 RtldLockState *lockstate) 2720 { 2721 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2722 return (-1); 2723 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2724 reloc_gnu_ifunc(obj, flags, lockstate) == -1) 2725 return (-1); 2726 return (0); 2727 } 2728 2729 static int 2730 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags, 2731 RtldLockState *lockstate) 2732 { 2733 Obj_Entry *obj; 2734 2735 for (obj = first; obj != NULL; obj = obj->next) { 2736 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1) 2737 return (-1); 2738 } 2739 return (0); 2740 } 2741 2742 static int 2743 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2744 RtldLockState *lockstate) 2745 { 2746 Objlist_Entry *elm; 2747 2748 STAILQ_FOREACH(elm, list, link) { 2749 if (resolve_object_ifunc(elm->obj, bind_now, flags, 2750 lockstate) == -1) 2751 return (-1); 2752 } 2753 return (0); 2754 } 2755 2756 /* 2757 * Cleanup procedure. It will be called (by the atexit mechanism) just 2758 * before the process exits. 2759 */ 2760 static void 2761 rtld_exit(void) 2762 { 2763 RtldLockState lockstate; 2764 2765 wlock_acquire(rtld_bind_lock, &lockstate); 2766 dbg("rtld_exit()"); 2767 objlist_call_fini(&list_fini, NULL, &lockstate); 2768 /* No need to remove the items from the list, since we are exiting. */ 2769 if (!libmap_disable) 2770 lm_fini(); 2771 lock_release(rtld_bind_lock, &lockstate); 2772 } 2773 2774 /* 2775 * Iterate over a search path, translate each element, and invoke the 2776 * callback on the result. 2777 */ 2778 static void * 2779 path_enumerate(const char *path, path_enum_proc callback, void *arg) 2780 { 2781 const char *trans; 2782 if (path == NULL) 2783 return (NULL); 2784 2785 path += strspn(path, ":;"); 2786 while (*path != '\0') { 2787 size_t len; 2788 char *res; 2789 2790 len = strcspn(path, ":;"); 2791 trans = lm_findn(NULL, path, len); 2792 if (trans) 2793 res = callback(trans, strlen(trans), arg); 2794 else 2795 res = callback(path, len, arg); 2796 2797 if (res != NULL) 2798 return (res); 2799 2800 path += len; 2801 path += strspn(path, ":;"); 2802 } 2803 2804 return (NULL); 2805 } 2806 2807 struct try_library_args { 2808 const char *name; 2809 size_t namelen; 2810 char *buffer; 2811 size_t buflen; 2812 }; 2813 2814 static void * 2815 try_library_path(const char *dir, size_t dirlen, void *param) 2816 { 2817 struct try_library_args *arg; 2818 2819 arg = param; 2820 if (*dir == '/' || trust) { 2821 char *pathname; 2822 2823 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 2824 return (NULL); 2825 2826 pathname = arg->buffer; 2827 strncpy(pathname, dir, dirlen); 2828 pathname[dirlen] = '/'; 2829 strcpy(pathname + dirlen + 1, arg->name); 2830 2831 dbg(" Trying \"%s\"", pathname); 2832 if (access(pathname, F_OK) == 0) { /* We found it */ 2833 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 2834 strcpy(pathname, arg->buffer); 2835 return (pathname); 2836 } 2837 } 2838 return (NULL); 2839 } 2840 2841 static char * 2842 search_library_path(const char *name, const char *path) 2843 { 2844 char *p; 2845 struct try_library_args arg; 2846 2847 if (path == NULL) 2848 return NULL; 2849 2850 arg.name = name; 2851 arg.namelen = strlen(name); 2852 arg.buffer = xmalloc(PATH_MAX); 2853 arg.buflen = PATH_MAX; 2854 2855 p = path_enumerate(path, try_library_path, &arg); 2856 2857 free(arg.buffer); 2858 2859 return (p); 2860 } 2861 2862 2863 /* 2864 * Finds the library with the given name using the directory descriptors 2865 * listed in the LD_LIBRARY_PATH_FDS environment variable. 2866 * 2867 * Returns a freshly-opened close-on-exec file descriptor for the library, 2868 * or -1 if the library cannot be found. 2869 */ 2870 static char * 2871 search_library_pathfds(const char *name, const char *path, int *fdp) 2872 { 2873 char *envcopy, *fdstr, *found, *last_token; 2874 size_t len; 2875 int dirfd, fd; 2876 2877 dbg("%s('%s', '%s', fdp)", __func__, name, path); 2878 2879 /* Don't load from user-specified libdirs into setuid binaries. */ 2880 if (!trust) 2881 return (NULL); 2882 2883 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 2884 if (path == NULL) 2885 return (NULL); 2886 2887 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 2888 if (name[0] == '/') { 2889 dbg("Absolute path (%s) passed to %s", name, __func__); 2890 return (NULL); 2891 } 2892 2893 /* 2894 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 2895 * copy of the path, as strtok_r rewrites separator tokens 2896 * with '\0'. 2897 */ 2898 found = NULL; 2899 envcopy = xstrdup(path); 2900 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 2901 fdstr = strtok_r(NULL, ":", &last_token)) { 2902 dirfd = parse_libdir(fdstr); 2903 if (dirfd < 0) 2904 break; 2905 fd = openat(dirfd, name, O_RDONLY | O_CLOEXEC); 2906 if (fd >= 0) { 2907 *fdp = fd; 2908 len = strlen(fdstr) + strlen(name) + 3; 2909 found = xmalloc(len); 2910 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 2911 _rtld_error("error generating '%d/%s'", 2912 dirfd, name); 2913 die(); 2914 } 2915 dbg("open('%s') => %d", found, fd); 2916 break; 2917 } 2918 } 2919 free(envcopy); 2920 2921 return (found); 2922 } 2923 2924 2925 int 2926 dlclose(void *handle) 2927 { 2928 Obj_Entry *root; 2929 RtldLockState lockstate; 2930 2931 wlock_acquire(rtld_bind_lock, &lockstate); 2932 root = dlcheck(handle); 2933 if (root == NULL) { 2934 lock_release(rtld_bind_lock, &lockstate); 2935 return -1; 2936 } 2937 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 2938 root->path); 2939 2940 /* Unreference the object and its dependencies. */ 2941 root->dl_refcount--; 2942 2943 if (root->refcount == 1) { 2944 /* 2945 * The object will be no longer referenced, so we must unload it. 2946 * First, call the fini functions. 2947 */ 2948 objlist_call_fini(&list_fini, root, &lockstate); 2949 2950 unref_dag(root); 2951 2952 /* Finish cleaning up the newly-unreferenced objects. */ 2953 GDB_STATE(RT_DELETE,&root->linkmap); 2954 unload_object(root); 2955 GDB_STATE(RT_CONSISTENT,NULL); 2956 } else 2957 unref_dag(root); 2958 2959 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 2960 lock_release(rtld_bind_lock, &lockstate); 2961 return 0; 2962 } 2963 2964 char * 2965 dlerror(void) 2966 { 2967 char *msg = error_message; 2968 error_message = NULL; 2969 return msg; 2970 } 2971 2972 void * 2973 dlopen(const char *name, int mode) 2974 { 2975 2976 return (rtld_dlopen(name, -1, mode)); 2977 } 2978 2979 void * 2980 fdlopen(int fd, int mode) 2981 { 2982 2983 return (rtld_dlopen(NULL, fd, mode)); 2984 } 2985 2986 static void * 2987 rtld_dlopen(const char *name, int fd, int mode) 2988 { 2989 RtldLockState lockstate; 2990 int lo_flags; 2991 2992 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 2993 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 2994 if (ld_tracing != NULL) { 2995 rlock_acquire(rtld_bind_lock, &lockstate); 2996 if (sigsetjmp(lockstate.env, 0) != 0) 2997 lock_upgrade(rtld_bind_lock, &lockstate); 2998 environ = (char **)*get_program_var_addr("environ", &lockstate); 2999 lock_release(rtld_bind_lock, &lockstate); 3000 } 3001 lo_flags = RTLD_LO_DLOPEN; 3002 if (mode & RTLD_NODELETE) 3003 lo_flags |= RTLD_LO_NODELETE; 3004 if (mode & RTLD_NOLOAD) 3005 lo_flags |= RTLD_LO_NOLOAD; 3006 if (ld_tracing != NULL) 3007 lo_flags |= RTLD_LO_TRACE; 3008 3009 return (dlopen_object(name, fd, obj_main, lo_flags, 3010 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3011 } 3012 3013 static void 3014 dlopen_cleanup(Obj_Entry *obj) 3015 { 3016 3017 obj->dl_refcount--; 3018 unref_dag(obj); 3019 if (obj->refcount == 0) 3020 unload_object(obj); 3021 } 3022 3023 static Obj_Entry * 3024 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3025 int mode, RtldLockState *lockstate) 3026 { 3027 Obj_Entry **old_obj_tail; 3028 Obj_Entry *obj; 3029 Objlist initlist; 3030 RtldLockState mlockstate; 3031 int result; 3032 3033 objlist_init(&initlist); 3034 3035 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3036 wlock_acquire(rtld_bind_lock, &mlockstate); 3037 lockstate = &mlockstate; 3038 } 3039 GDB_STATE(RT_ADD,NULL); 3040 3041 old_obj_tail = obj_tail; 3042 obj = NULL; 3043 if (name == NULL && fd == -1) { 3044 obj = obj_main; 3045 obj->refcount++; 3046 } else { 3047 obj = load_object(name, fd, refobj, lo_flags); 3048 } 3049 3050 if (obj) { 3051 obj->dl_refcount++; 3052 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3053 objlist_push_tail(&list_global, obj); 3054 if (*old_obj_tail != NULL) { /* We loaded something new. */ 3055 assert(*old_obj_tail == obj); 3056 result = load_needed_objects(obj, 3057 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 3058 init_dag(obj); 3059 ref_dag(obj); 3060 if (result != -1) 3061 result = rtld_verify_versions(&obj->dagmembers); 3062 if (result != -1 && ld_tracing) 3063 goto trace; 3064 if (result == -1 || relocate_object_dag(obj, 3065 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3066 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3067 lockstate) == -1) { 3068 dlopen_cleanup(obj); 3069 obj = NULL; 3070 } else if (lo_flags & RTLD_LO_EARLY) { 3071 /* 3072 * Do not call the init functions for early loaded 3073 * filtees. The image is still not initialized enough 3074 * for them to work. 3075 * 3076 * Our object is found by the global object list and 3077 * will be ordered among all init calls done right 3078 * before transferring control to main. 3079 */ 3080 } else { 3081 /* Make list of init functions to call. */ 3082 initlist_add_objects(obj, &obj->next, &initlist); 3083 } 3084 /* 3085 * Process all no_delete objects here, given them own 3086 * DAGs to prevent their dependencies from being unloaded. 3087 * This has to be done after we have loaded all of the 3088 * dependencies, so that we do not miss any. 3089 */ 3090 if (obj != NULL) 3091 process_nodelete(obj); 3092 } else { 3093 /* 3094 * Bump the reference counts for objects on this DAG. If 3095 * this is the first dlopen() call for the object that was 3096 * already loaded as a dependency, initialize the dag 3097 * starting at it. 3098 */ 3099 init_dag(obj); 3100 ref_dag(obj); 3101 3102 if ((lo_flags & RTLD_LO_TRACE) != 0) 3103 goto trace; 3104 } 3105 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3106 obj->z_nodelete) && !obj->ref_nodel) { 3107 dbg("obj %s nodelete", obj->path); 3108 ref_dag(obj); 3109 obj->z_nodelete = obj->ref_nodel = true; 3110 } 3111 } 3112 3113 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3114 name); 3115 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3116 3117 if (!(lo_flags & RTLD_LO_EARLY)) { 3118 map_stacks_exec(lockstate); 3119 } 3120 3121 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3122 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3123 lockstate) == -1) { 3124 objlist_clear(&initlist); 3125 dlopen_cleanup(obj); 3126 if (lockstate == &mlockstate) 3127 lock_release(rtld_bind_lock, lockstate); 3128 return (NULL); 3129 } 3130 3131 if (!(lo_flags & RTLD_LO_EARLY)) { 3132 /* Call the init functions. */ 3133 objlist_call_init(&initlist, lockstate); 3134 } 3135 objlist_clear(&initlist); 3136 if (lockstate == &mlockstate) 3137 lock_release(rtld_bind_lock, lockstate); 3138 return obj; 3139 trace: 3140 trace_loaded_objects(obj); 3141 if (lockstate == &mlockstate) 3142 lock_release(rtld_bind_lock, lockstate); 3143 exit(0); 3144 } 3145 3146 static void * 3147 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3148 int flags) 3149 { 3150 DoneList donelist; 3151 const Obj_Entry *obj, *defobj; 3152 const Elf_Sym *def; 3153 SymLook req; 3154 RtldLockState lockstate; 3155 tls_index ti; 3156 int res; 3157 3158 def = NULL; 3159 defobj = NULL; 3160 symlook_init(&req, name); 3161 req.ventry = ve; 3162 req.flags = flags | SYMLOOK_IN_PLT; 3163 req.lockstate = &lockstate; 3164 3165 rlock_acquire(rtld_bind_lock, &lockstate); 3166 if (sigsetjmp(lockstate.env, 0) != 0) 3167 lock_upgrade(rtld_bind_lock, &lockstate); 3168 if (handle == NULL || handle == RTLD_NEXT || 3169 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3170 3171 if ((obj = obj_from_addr(retaddr)) == NULL) { 3172 _rtld_error("Cannot determine caller's shared object"); 3173 lock_release(rtld_bind_lock, &lockstate); 3174 return NULL; 3175 } 3176 if (handle == NULL) { /* Just the caller's shared object. */ 3177 res = symlook_obj(&req, obj); 3178 if (res == 0) { 3179 def = req.sym_out; 3180 defobj = req.defobj_out; 3181 } 3182 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3183 handle == RTLD_SELF) { /* ... caller included */ 3184 if (handle == RTLD_NEXT) 3185 obj = obj->next; 3186 for (; obj != NULL; obj = obj->next) { 3187 res = symlook_obj(&req, obj); 3188 if (res == 0) { 3189 if (def == NULL || 3190 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3191 def = req.sym_out; 3192 defobj = req.defobj_out; 3193 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3194 break; 3195 } 3196 } 3197 } 3198 /* 3199 * Search the dynamic linker itself, and possibly resolve the 3200 * symbol from there. This is how the application links to 3201 * dynamic linker services such as dlopen. 3202 */ 3203 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3204 res = symlook_obj(&req, &obj_rtld); 3205 if (res == 0) { 3206 def = req.sym_out; 3207 defobj = req.defobj_out; 3208 } 3209 } 3210 } else { 3211 assert(handle == RTLD_DEFAULT); 3212 res = symlook_default(&req, obj); 3213 if (res == 0) { 3214 defobj = req.defobj_out; 3215 def = req.sym_out; 3216 } 3217 } 3218 } else { 3219 if ((obj = dlcheck(handle)) == NULL) { 3220 lock_release(rtld_bind_lock, &lockstate); 3221 return NULL; 3222 } 3223 3224 donelist_init(&donelist); 3225 if (obj->mainprog) { 3226 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3227 res = symlook_global(&req, &donelist); 3228 if (res == 0) { 3229 def = req.sym_out; 3230 defobj = req.defobj_out; 3231 } 3232 /* 3233 * Search the dynamic linker itself, and possibly resolve the 3234 * symbol from there. This is how the application links to 3235 * dynamic linker services such as dlopen. 3236 */ 3237 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3238 res = symlook_obj(&req, &obj_rtld); 3239 if (res == 0) { 3240 def = req.sym_out; 3241 defobj = req.defobj_out; 3242 } 3243 } 3244 } 3245 else { 3246 /* Search the whole DAG rooted at the given object. */ 3247 res = symlook_list(&req, &obj->dagmembers, &donelist); 3248 if (res == 0) { 3249 def = req.sym_out; 3250 defobj = req.defobj_out; 3251 } 3252 } 3253 } 3254 3255 if (def != NULL) { 3256 lock_release(rtld_bind_lock, &lockstate); 3257 3258 /* 3259 * The value required by the caller is derived from the value 3260 * of the symbol. this is simply the relocated value of the 3261 * symbol. 3262 */ 3263 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3264 return (make_function_pointer(def, defobj)); 3265 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3266 return (rtld_resolve_ifunc(defobj, def)); 3267 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3268 ti.ti_module = defobj->tlsindex; 3269 ti.ti_offset = def->st_value; 3270 return (__tls_get_addr(&ti)); 3271 } else 3272 return (defobj->relocbase + def->st_value); 3273 } 3274 3275 _rtld_error("Undefined symbol \"%s\"", name); 3276 lock_release(rtld_bind_lock, &lockstate); 3277 return NULL; 3278 } 3279 3280 void * 3281 dlsym(void *handle, const char *name) 3282 { 3283 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3284 SYMLOOK_DLSYM); 3285 } 3286 3287 dlfunc_t 3288 dlfunc(void *handle, const char *name) 3289 { 3290 union { 3291 void *d; 3292 dlfunc_t f; 3293 } rv; 3294 3295 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3296 SYMLOOK_DLSYM); 3297 return (rv.f); 3298 } 3299 3300 void * 3301 dlvsym(void *handle, const char *name, const char *version) 3302 { 3303 Ver_Entry ventry; 3304 3305 ventry.name = version; 3306 ventry.file = NULL; 3307 ventry.hash = elf_hash(version); 3308 ventry.flags= 0; 3309 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3310 SYMLOOK_DLSYM); 3311 } 3312 3313 int 3314 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3315 { 3316 const Obj_Entry *obj; 3317 RtldLockState lockstate; 3318 3319 rlock_acquire(rtld_bind_lock, &lockstate); 3320 obj = obj_from_addr(addr); 3321 if (obj == NULL) { 3322 _rtld_error("No shared object contains address"); 3323 lock_release(rtld_bind_lock, &lockstate); 3324 return (0); 3325 } 3326 rtld_fill_dl_phdr_info(obj, phdr_info); 3327 lock_release(rtld_bind_lock, &lockstate); 3328 return (1); 3329 } 3330 3331 int 3332 dladdr(const void *addr, Dl_info *info) 3333 { 3334 const Obj_Entry *obj; 3335 const Elf_Sym *def; 3336 void *symbol_addr; 3337 unsigned long symoffset; 3338 RtldLockState lockstate; 3339 3340 rlock_acquire(rtld_bind_lock, &lockstate); 3341 obj = obj_from_addr(addr); 3342 if (obj == NULL) { 3343 _rtld_error("No shared object contains address"); 3344 lock_release(rtld_bind_lock, &lockstate); 3345 return 0; 3346 } 3347 info->dli_fname = obj->path; 3348 info->dli_fbase = obj->mapbase; 3349 info->dli_saddr = NULL; 3350 info->dli_sname = NULL; 3351 3352 /* 3353 * Walk the symbol list looking for the symbol whose address is 3354 * closest to the address sent in. 3355 */ 3356 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3357 def = obj->symtab + symoffset; 3358 3359 /* 3360 * For skip the symbol if st_shndx is either SHN_UNDEF or 3361 * SHN_COMMON. 3362 */ 3363 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3364 continue; 3365 3366 /* 3367 * If the symbol is greater than the specified address, or if it 3368 * is further away from addr than the current nearest symbol, 3369 * then reject it. 3370 */ 3371 symbol_addr = obj->relocbase + def->st_value; 3372 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3373 continue; 3374 3375 /* Update our idea of the nearest symbol. */ 3376 info->dli_sname = obj->strtab + def->st_name; 3377 info->dli_saddr = symbol_addr; 3378 3379 /* Exact match? */ 3380 if (info->dli_saddr == addr) 3381 break; 3382 } 3383 lock_release(rtld_bind_lock, &lockstate); 3384 return 1; 3385 } 3386 3387 int 3388 dlinfo(void *handle, int request, void *p) 3389 { 3390 const Obj_Entry *obj; 3391 RtldLockState lockstate; 3392 int error; 3393 3394 rlock_acquire(rtld_bind_lock, &lockstate); 3395 3396 if (handle == NULL || handle == RTLD_SELF) { 3397 void *retaddr; 3398 3399 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3400 if ((obj = obj_from_addr(retaddr)) == NULL) 3401 _rtld_error("Cannot determine caller's shared object"); 3402 } else 3403 obj = dlcheck(handle); 3404 3405 if (obj == NULL) { 3406 lock_release(rtld_bind_lock, &lockstate); 3407 return (-1); 3408 } 3409 3410 error = 0; 3411 switch (request) { 3412 case RTLD_DI_LINKMAP: 3413 *((struct link_map const **)p) = &obj->linkmap; 3414 break; 3415 case RTLD_DI_ORIGIN: 3416 error = rtld_dirname(obj->path, p); 3417 break; 3418 3419 case RTLD_DI_SERINFOSIZE: 3420 case RTLD_DI_SERINFO: 3421 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3422 break; 3423 3424 default: 3425 _rtld_error("Invalid request %d passed to dlinfo()", request); 3426 error = -1; 3427 } 3428 3429 lock_release(rtld_bind_lock, &lockstate); 3430 3431 return (error); 3432 } 3433 3434 static void 3435 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3436 { 3437 3438 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3439 phdr_info->dlpi_name = obj->path; 3440 phdr_info->dlpi_phdr = obj->phdr; 3441 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3442 phdr_info->dlpi_tls_modid = obj->tlsindex; 3443 phdr_info->dlpi_tls_data = obj->tlsinit; 3444 phdr_info->dlpi_adds = obj_loads; 3445 phdr_info->dlpi_subs = obj_loads - obj_count; 3446 } 3447 3448 int 3449 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3450 { 3451 struct dl_phdr_info phdr_info; 3452 const Obj_Entry *obj; 3453 RtldLockState bind_lockstate, phdr_lockstate; 3454 int error; 3455 3456 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3457 rlock_acquire(rtld_bind_lock, &bind_lockstate); 3458 3459 error = 0; 3460 3461 for (obj = obj_list; obj != NULL; obj = obj->next) { 3462 rtld_fill_dl_phdr_info(obj, &phdr_info); 3463 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0) 3464 break; 3465 3466 } 3467 if (error == 0) { 3468 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3469 error = callback(&phdr_info, sizeof(phdr_info), param); 3470 } 3471 3472 lock_release(rtld_bind_lock, &bind_lockstate); 3473 lock_release(rtld_phdr_lock, &phdr_lockstate); 3474 3475 return (error); 3476 } 3477 3478 static void * 3479 fill_search_info(const char *dir, size_t dirlen, void *param) 3480 { 3481 struct fill_search_info_args *arg; 3482 3483 arg = param; 3484 3485 if (arg->request == RTLD_DI_SERINFOSIZE) { 3486 arg->serinfo->dls_cnt ++; 3487 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3488 } else { 3489 struct dl_serpath *s_entry; 3490 3491 s_entry = arg->serpath; 3492 s_entry->dls_name = arg->strspace; 3493 s_entry->dls_flags = arg->flags; 3494 3495 strncpy(arg->strspace, dir, dirlen); 3496 arg->strspace[dirlen] = '\0'; 3497 3498 arg->strspace += dirlen + 1; 3499 arg->serpath++; 3500 } 3501 3502 return (NULL); 3503 } 3504 3505 static int 3506 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3507 { 3508 struct dl_serinfo _info; 3509 struct fill_search_info_args args; 3510 3511 args.request = RTLD_DI_SERINFOSIZE; 3512 args.serinfo = &_info; 3513 3514 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3515 _info.dls_cnt = 0; 3516 3517 path_enumerate(obj->rpath, fill_search_info, &args); 3518 path_enumerate(ld_library_path, fill_search_info, &args); 3519 path_enumerate(obj->runpath, fill_search_info, &args); 3520 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args); 3521 if (!obj->z_nodeflib) 3522 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 3523 3524 3525 if (request == RTLD_DI_SERINFOSIZE) { 3526 info->dls_size = _info.dls_size; 3527 info->dls_cnt = _info.dls_cnt; 3528 return (0); 3529 } 3530 3531 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3532 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3533 return (-1); 3534 } 3535 3536 args.request = RTLD_DI_SERINFO; 3537 args.serinfo = info; 3538 args.serpath = &info->dls_serpath[0]; 3539 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3540 3541 args.flags = LA_SER_RUNPATH; 3542 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 3543 return (-1); 3544 3545 args.flags = LA_SER_LIBPATH; 3546 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 3547 return (-1); 3548 3549 args.flags = LA_SER_RUNPATH; 3550 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL) 3551 return (-1); 3552 3553 args.flags = LA_SER_CONFIG; 3554 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args) 3555 != NULL) 3556 return (-1); 3557 3558 args.flags = LA_SER_DEFAULT; 3559 if (!obj->z_nodeflib && 3560 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 3561 return (-1); 3562 return (0); 3563 } 3564 3565 static int 3566 rtld_dirname(const char *path, char *bname) 3567 { 3568 const char *endp; 3569 3570 /* Empty or NULL string gets treated as "." */ 3571 if (path == NULL || *path == '\0') { 3572 bname[0] = '.'; 3573 bname[1] = '\0'; 3574 return (0); 3575 } 3576 3577 /* Strip trailing slashes */ 3578 endp = path + strlen(path) - 1; 3579 while (endp > path && *endp == '/') 3580 endp--; 3581 3582 /* Find the start of the dir */ 3583 while (endp > path && *endp != '/') 3584 endp--; 3585 3586 /* Either the dir is "/" or there are no slashes */ 3587 if (endp == path) { 3588 bname[0] = *endp == '/' ? '/' : '.'; 3589 bname[1] = '\0'; 3590 return (0); 3591 } else { 3592 do { 3593 endp--; 3594 } while (endp > path && *endp == '/'); 3595 } 3596 3597 if (endp - path + 2 > PATH_MAX) 3598 { 3599 _rtld_error("Filename is too long: %s", path); 3600 return(-1); 3601 } 3602 3603 strncpy(bname, path, endp - path + 1); 3604 bname[endp - path + 1] = '\0'; 3605 return (0); 3606 } 3607 3608 static int 3609 rtld_dirname_abs(const char *path, char *base) 3610 { 3611 char base_rel[PATH_MAX]; 3612 3613 if (rtld_dirname(path, base) == -1) 3614 return (-1); 3615 if (base[0] == '/') 3616 return (0); 3617 if (getcwd(base_rel, sizeof(base_rel)) == NULL || 3618 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) || 3619 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel)) 3620 return (-1); 3621 strcpy(base, base_rel); 3622 return (0); 3623 } 3624 3625 static void 3626 linkmap_add(Obj_Entry *obj) 3627 { 3628 struct link_map *l = &obj->linkmap; 3629 struct link_map *prev; 3630 3631 obj->linkmap.l_name = obj->path; 3632 obj->linkmap.l_addr = obj->mapbase; 3633 obj->linkmap.l_ld = obj->dynamic; 3634 3635 if (r_debug.r_map == NULL) { 3636 r_debug.r_map = l; 3637 return; 3638 } 3639 3640 /* 3641 * Scan to the end of the list, but not past the entry for the 3642 * dynamic linker, which we want to keep at the very end. 3643 */ 3644 for (prev = r_debug.r_map; 3645 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3646 prev = prev->l_next) 3647 ; 3648 3649 /* Link in the new entry. */ 3650 l->l_prev = prev; 3651 l->l_next = prev->l_next; 3652 if (l->l_next != NULL) 3653 l->l_next->l_prev = l; 3654 prev->l_next = l; 3655 } 3656 3657 static void 3658 linkmap_delete(Obj_Entry *obj) 3659 { 3660 struct link_map *l = &obj->linkmap; 3661 3662 if (l->l_prev == NULL) { 3663 if ((r_debug.r_map = l->l_next) != NULL) 3664 l->l_next->l_prev = NULL; 3665 return; 3666 } 3667 3668 if ((l->l_prev->l_next = l->l_next) != NULL) 3669 l->l_next->l_prev = l->l_prev; 3670 } 3671 3672 /* 3673 * Function for the debugger to set a breakpoint on to gain control. 3674 * 3675 * The two parameters allow the debugger to easily find and determine 3676 * what the runtime loader is doing and to whom it is doing it. 3677 * 3678 * When the loadhook trap is hit (r_debug_state, set at program 3679 * initialization), the arguments can be found on the stack: 3680 * 3681 * +8 struct link_map *m 3682 * +4 struct r_debug *rd 3683 * +0 RetAddr 3684 */ 3685 void 3686 r_debug_state(struct r_debug* rd, struct link_map *m) 3687 { 3688 /* 3689 * The following is a hack to force the compiler to emit calls to 3690 * this function, even when optimizing. If the function is empty, 3691 * the compiler is not obliged to emit any code for calls to it, 3692 * even when marked __noinline. However, gdb depends on those 3693 * calls being made. 3694 */ 3695 __asm __volatile("" : : : "memory"); 3696 } 3697 3698 /* 3699 * A function called after init routines have completed. This can be used to 3700 * break before a program's entry routine is called, and can be used when 3701 * main is not available in the symbol table. 3702 */ 3703 void 3704 _r_debug_postinit(struct link_map *m) 3705 { 3706 3707 /* See r_debug_state(). */ 3708 __asm __volatile("" : : : "memory"); 3709 } 3710 3711 /* 3712 * Get address of the pointer variable in the main program. 3713 * Prefer non-weak symbol over the weak one. 3714 */ 3715 static const void ** 3716 get_program_var_addr(const char *name, RtldLockState *lockstate) 3717 { 3718 SymLook req; 3719 DoneList donelist; 3720 3721 symlook_init(&req, name); 3722 req.lockstate = lockstate; 3723 donelist_init(&donelist); 3724 if (symlook_global(&req, &donelist) != 0) 3725 return (NULL); 3726 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 3727 return ((const void **)make_function_pointer(req.sym_out, 3728 req.defobj_out)); 3729 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 3730 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 3731 else 3732 return ((const void **)(req.defobj_out->relocbase + 3733 req.sym_out->st_value)); 3734 } 3735 3736 /* 3737 * Set a pointer variable in the main program to the given value. This 3738 * is used to set key variables such as "environ" before any of the 3739 * init functions are called. 3740 */ 3741 static void 3742 set_program_var(const char *name, const void *value) 3743 { 3744 const void **addr; 3745 3746 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 3747 dbg("\"%s\": *%p <-- %p", name, addr, value); 3748 *addr = value; 3749 } 3750 } 3751 3752 /* 3753 * Search the global objects, including dependencies and main object, 3754 * for the given symbol. 3755 */ 3756 static int 3757 symlook_global(SymLook *req, DoneList *donelist) 3758 { 3759 SymLook req1; 3760 const Objlist_Entry *elm; 3761 int res; 3762 3763 symlook_init_from_req(&req1, req); 3764 3765 /* Search all objects loaded at program start up. */ 3766 if (req->defobj_out == NULL || 3767 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3768 res = symlook_list(&req1, &list_main, donelist); 3769 if (res == 0 && (req->defobj_out == NULL || 3770 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3771 req->sym_out = req1.sym_out; 3772 req->defobj_out = req1.defobj_out; 3773 assert(req->defobj_out != NULL); 3774 } 3775 } 3776 3777 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 3778 STAILQ_FOREACH(elm, &list_global, link) { 3779 if (req->defobj_out != NULL && 3780 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3781 break; 3782 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 3783 if (res == 0 && (req->defobj_out == NULL || 3784 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3785 req->sym_out = req1.sym_out; 3786 req->defobj_out = req1.defobj_out; 3787 assert(req->defobj_out != NULL); 3788 } 3789 } 3790 3791 return (req->sym_out != NULL ? 0 : ESRCH); 3792 } 3793 3794 /* 3795 * This is a special version of getenv which is far more efficient 3796 * at finding LD_ environment vars. 3797 */ 3798 static 3799 const char * 3800 _getenv_ld(const char *id) 3801 { 3802 const char *envp; 3803 int i, j; 3804 int idlen = strlen(id); 3805 3806 if (ld_index == LD_ARY_CACHE) 3807 return(getenv(id)); 3808 if (ld_index == 0) { 3809 for (i = j = 0; (envp = environ[i]) != NULL && j < LD_ARY_CACHE; ++i) { 3810 if (envp[0] == 'L' && envp[1] == 'D' && envp[2] == '_') 3811 ld_ary[j++] = envp; 3812 } 3813 if (j == 0) 3814 ld_ary[j++] = ""; 3815 ld_index = j; 3816 } 3817 for (i = ld_index - 1; i >= 0; --i) { 3818 if (strncmp(ld_ary[i], id, idlen) == 0 && ld_ary[i][idlen] == '=') 3819 return(ld_ary[i] + idlen + 1); 3820 } 3821 return(NULL); 3822 } 3823 3824 /* 3825 * Given a symbol name in a referencing object, find the corresponding 3826 * definition of the symbol. Returns a pointer to the symbol, or NULL if 3827 * no definition was found. Returns a pointer to the Obj_Entry of the 3828 * defining object via the reference parameter DEFOBJ_OUT. 3829 */ 3830 static int 3831 symlook_default(SymLook *req, const Obj_Entry *refobj) 3832 { 3833 DoneList donelist; 3834 const Objlist_Entry *elm; 3835 SymLook req1; 3836 int res; 3837 3838 donelist_init(&donelist); 3839 symlook_init_from_req(&req1, req); 3840 3841 /* Look first in the referencing object if linked symbolically. */ 3842 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 3843 res = symlook_obj(&req1, refobj); 3844 if (res == 0) { 3845 req->sym_out = req1.sym_out; 3846 req->defobj_out = req1.defobj_out; 3847 assert(req->defobj_out != NULL); 3848 } 3849 } 3850 3851 symlook_global(req, &donelist); 3852 3853 /* Search all dlopened DAGs containing the referencing object. */ 3854 STAILQ_FOREACH(elm, &refobj->dldags, link) { 3855 if (req->sym_out != NULL && 3856 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3857 break; 3858 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 3859 if (res == 0 && (req->sym_out == NULL || 3860 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3861 req->sym_out = req1.sym_out; 3862 req->defobj_out = req1.defobj_out; 3863 assert(req->defobj_out != NULL); 3864 } 3865 } 3866 3867 /* 3868 * Search the dynamic linker itself, and possibly resolve the 3869 * symbol from there. This is how the application links to 3870 * dynamic linker services such as dlopen. 3871 */ 3872 if (req->sym_out == NULL || 3873 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3874 res = symlook_obj(&req1, &obj_rtld); 3875 if (res == 0) { 3876 req->sym_out = req1.sym_out; 3877 req->defobj_out = req1.defobj_out; 3878 assert(req->defobj_out != NULL); 3879 } 3880 } 3881 3882 return (req->sym_out != NULL ? 0 : ESRCH); 3883 } 3884 3885 static int 3886 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 3887 { 3888 const Elf_Sym *def; 3889 const Obj_Entry *defobj; 3890 const Objlist_Entry *elm; 3891 SymLook req1; 3892 int res; 3893 3894 def = NULL; 3895 defobj = NULL; 3896 STAILQ_FOREACH(elm, objlist, link) { 3897 if (donelist_check(dlp, elm->obj)) 3898 continue; 3899 symlook_init_from_req(&req1, req); 3900 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 3901 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3902 def = req1.sym_out; 3903 defobj = req1.defobj_out; 3904 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3905 break; 3906 } 3907 } 3908 } 3909 if (def != NULL) { 3910 req->sym_out = def; 3911 req->defobj_out = defobj; 3912 return (0); 3913 } 3914 return (ESRCH); 3915 } 3916 3917 /* 3918 * Search the chain of DAGS cointed to by the given Needed_Entry 3919 * for a symbol of the given name. Each DAG is scanned completely 3920 * before advancing to the next one. Returns a pointer to the symbol, 3921 * or NULL if no definition was found. 3922 */ 3923 static int 3924 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 3925 { 3926 const Elf_Sym *def; 3927 const Needed_Entry *n; 3928 const Obj_Entry *defobj; 3929 SymLook req1; 3930 int res; 3931 3932 def = NULL; 3933 defobj = NULL; 3934 symlook_init_from_req(&req1, req); 3935 for (n = needed; n != NULL; n = n->next) { 3936 if (n->obj == NULL || 3937 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 3938 continue; 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 if (def != NULL) { 3947 req->sym_out = def; 3948 req->defobj_out = defobj; 3949 return (0); 3950 } 3951 return (ESRCH); 3952 } 3953 3954 /* 3955 * Search the symbol table of a single shared object for a symbol of 3956 * the given name and version, if requested. Returns a pointer to the 3957 * symbol, or NULL if no definition was found. If the object is 3958 * filter, return filtered symbol from filtee. 3959 * 3960 * The symbol's hash value is passed in for efficiency reasons; that 3961 * eliminates many recomputations of the hash value. 3962 */ 3963 int 3964 symlook_obj(SymLook *req, const Obj_Entry *obj) 3965 { 3966 DoneList donelist; 3967 SymLook req1; 3968 int flags, res, mres; 3969 3970 /* 3971 * If there is at least one valid hash at this point, we prefer to 3972 * use the faster GNU version if available. 3973 */ 3974 if (obj->valid_hash_gnu) 3975 mres = symlook_obj1_gnu(req, obj); 3976 else if (obj->valid_hash_sysv) 3977 mres = symlook_obj1_sysv(req, obj); 3978 else 3979 return (EINVAL); 3980 3981 if (mres == 0) { 3982 if (obj->needed_filtees != NULL) { 3983 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3984 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3985 donelist_init(&donelist); 3986 symlook_init_from_req(&req1, req); 3987 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 3988 if (res == 0) { 3989 req->sym_out = req1.sym_out; 3990 req->defobj_out = req1.defobj_out; 3991 } 3992 return (res); 3993 } 3994 if (obj->needed_aux_filtees != NULL) { 3995 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3996 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3997 donelist_init(&donelist); 3998 symlook_init_from_req(&req1, req); 3999 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 4000 if (res == 0) { 4001 req->sym_out = req1.sym_out; 4002 req->defobj_out = req1.defobj_out; 4003 return (res); 4004 } 4005 } 4006 } 4007 return (mres); 4008 } 4009 4010 /* Symbol match routine common to both hash functions */ 4011 static bool 4012 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4013 const unsigned long symnum) 4014 { 4015 Elf_Versym verndx; 4016 const Elf_Sym *symp; 4017 const char *strp; 4018 4019 symp = obj->symtab + symnum; 4020 strp = obj->strtab + symp->st_name; 4021 4022 switch (ELF_ST_TYPE(symp->st_info)) { 4023 case STT_FUNC: 4024 case STT_NOTYPE: 4025 case STT_OBJECT: 4026 case STT_COMMON: 4027 case STT_GNU_IFUNC: 4028 if (symp->st_value == 0) 4029 return (false); 4030 /* fallthrough */ 4031 case STT_TLS: 4032 if (symp->st_shndx != SHN_UNDEF) 4033 break; 4034 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4035 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4036 break; 4037 /* fallthrough */ 4038 default: 4039 return (false); 4040 } 4041 if (strcmp(req->name, strp) != 0) 4042 return (false); 4043 4044 if (req->ventry == NULL) { 4045 if (obj->versyms != NULL) { 4046 verndx = VER_NDX(obj->versyms[symnum]); 4047 if (verndx > obj->vernum) { 4048 _rtld_error( 4049 "%s: symbol %s references wrong version %d", 4050 obj->path, obj->strtab + symnum, verndx); 4051 return (false); 4052 } 4053 /* 4054 * If we are not called from dlsym (i.e. this 4055 * is a normal relocation from unversioned 4056 * binary), accept the symbol immediately if 4057 * it happens to have first version after this 4058 * shared object became versioned. Otherwise, 4059 * if symbol is versioned and not hidden, 4060 * remember it. If it is the only symbol with 4061 * this name exported by the shared object, it 4062 * will be returned as a match by the calling 4063 * function. If symbol is global (verndx < 2) 4064 * accept it unconditionally. 4065 */ 4066 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4067 verndx == VER_NDX_GIVEN) { 4068 result->sym_out = symp; 4069 return (true); 4070 } 4071 else if (verndx >= VER_NDX_GIVEN) { 4072 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4073 == 0) { 4074 if (result->vsymp == NULL) 4075 result->vsymp = symp; 4076 result->vcount++; 4077 } 4078 return (false); 4079 } 4080 } 4081 result->sym_out = symp; 4082 return (true); 4083 } 4084 if (obj->versyms == NULL) { 4085 if (object_match_name(obj, req->ventry->name)) { 4086 _rtld_error("%s: object %s should provide version %s " 4087 "for symbol %s", obj_rtld.path, obj->path, 4088 req->ventry->name, obj->strtab + symnum); 4089 return (false); 4090 } 4091 } else { 4092 verndx = VER_NDX(obj->versyms[symnum]); 4093 if (verndx > obj->vernum) { 4094 _rtld_error("%s: symbol %s references wrong version %d", 4095 obj->path, obj->strtab + symnum, verndx); 4096 return (false); 4097 } 4098 if (obj->vertab[verndx].hash != req->ventry->hash || 4099 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4100 /* 4101 * Version does not match. Look if this is a 4102 * global symbol and if it is not hidden. If 4103 * global symbol (verndx < 2) is available, 4104 * use it. Do not return symbol if we are 4105 * called by dlvsym, because dlvsym looks for 4106 * a specific version and default one is not 4107 * what dlvsym wants. 4108 */ 4109 if ((req->flags & SYMLOOK_DLSYM) || 4110 (verndx >= VER_NDX_GIVEN) || 4111 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4112 return (false); 4113 } 4114 } 4115 result->sym_out = symp; 4116 return (true); 4117 } 4118 4119 /* 4120 * Search for symbol using SysV hash function. 4121 * obj->buckets is known not to be NULL at this point; the test for this was 4122 * performed with the obj->valid_hash_sysv assignment. 4123 */ 4124 static int 4125 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4126 { 4127 unsigned long symnum; 4128 Sym_Match_Result matchres; 4129 4130 matchres.sym_out = NULL; 4131 matchres.vsymp = NULL; 4132 matchres.vcount = 0; 4133 4134 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4135 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4136 if (symnum >= obj->nchains) 4137 return (ESRCH); /* Bad object */ 4138 4139 if (matched_symbol(req, obj, &matchres, symnum)) { 4140 req->sym_out = matchres.sym_out; 4141 req->defobj_out = obj; 4142 return (0); 4143 } 4144 } 4145 if (matchres.vcount == 1) { 4146 req->sym_out = matchres.vsymp; 4147 req->defobj_out = obj; 4148 return (0); 4149 } 4150 return (ESRCH); 4151 } 4152 4153 /* Search for symbol using GNU hash function */ 4154 static int 4155 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4156 { 4157 Elf_Addr bloom_word; 4158 const Elf32_Word *hashval; 4159 Elf32_Word bucket; 4160 Sym_Match_Result matchres; 4161 unsigned int h1, h2; 4162 unsigned long symnum; 4163 4164 matchres.sym_out = NULL; 4165 matchres.vsymp = NULL; 4166 matchres.vcount = 0; 4167 4168 /* Pick right bitmask word from Bloom filter array */ 4169 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4170 obj->maskwords_bm_gnu]; 4171 4172 /* Calculate modulus word size of gnu hash and its derivative */ 4173 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4174 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4175 4176 /* Filter out the "definitely not in set" queries */ 4177 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4178 return (ESRCH); 4179 4180 /* Locate hash chain and corresponding value element*/ 4181 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4182 if (bucket == 0) 4183 return (ESRCH); 4184 hashval = &obj->chain_zero_gnu[bucket]; 4185 do { 4186 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4187 symnum = hashval - obj->chain_zero_gnu; 4188 if (matched_symbol(req, obj, &matchres, symnum)) { 4189 req->sym_out = matchres.sym_out; 4190 req->defobj_out = obj; 4191 return (0); 4192 } 4193 } 4194 } while ((*hashval++ & 1) == 0); 4195 if (matchres.vcount == 1) { 4196 req->sym_out = matchres.vsymp; 4197 req->defobj_out = obj; 4198 return (0); 4199 } 4200 return (ESRCH); 4201 } 4202 4203 static void 4204 trace_loaded_objects(Obj_Entry *obj) 4205 { 4206 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4207 int c; 4208 4209 if ((main_local = _getenv_ld("LD_TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 4210 main_local = ""; 4211 4212 if ((fmt1 = _getenv_ld("LD_TRACE_LOADED_OBJECTS_FMT1")) == NULL) 4213 fmt1 = "\t%o => %p (%x)\n"; 4214 4215 if ((fmt2 = _getenv_ld("LD_TRACE_LOADED_OBJECTS_FMT2")) == NULL) 4216 fmt2 = "\t%o (%x)\n"; 4217 4218 list_containers = _getenv_ld("LD_TRACE_LOADED_OBJECTS_ALL"); 4219 4220 for (; obj; obj = obj->next) { 4221 Needed_Entry *needed; 4222 char *name, *path; 4223 bool is_lib; 4224 4225 if (list_containers && obj->needed != NULL) 4226 rtld_printf("%s:\n", obj->path); 4227 for (needed = obj->needed; needed; needed = needed->next) { 4228 if (needed->obj != NULL) { 4229 if (needed->obj->traced && !list_containers) 4230 continue; 4231 needed->obj->traced = true; 4232 path = needed->obj->path; 4233 } else 4234 path = "not found"; 4235 4236 name = (char *)obj->strtab + needed->name; 4237 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4238 4239 fmt = is_lib ? fmt1 : fmt2; 4240 while ((c = *fmt++) != '\0') { 4241 switch (c) { 4242 default: 4243 rtld_putchar(c); 4244 continue; 4245 case '\\': 4246 switch (c = *fmt) { 4247 case '\0': 4248 continue; 4249 case 'n': 4250 rtld_putchar('\n'); 4251 break; 4252 case 't': 4253 rtld_putchar('\t'); 4254 break; 4255 } 4256 break; 4257 case '%': 4258 switch (c = *fmt) { 4259 case '\0': 4260 continue; 4261 case '%': 4262 default: 4263 rtld_putchar(c); 4264 break; 4265 case 'A': 4266 rtld_putstr(main_local); 4267 break; 4268 case 'a': 4269 rtld_putstr(obj_main->path); 4270 break; 4271 case 'o': 4272 rtld_putstr(name); 4273 break; 4274 case 'p': 4275 rtld_putstr(path); 4276 break; 4277 case 'x': 4278 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4279 0); 4280 break; 4281 } 4282 break; 4283 } 4284 ++fmt; 4285 } 4286 } 4287 } 4288 } 4289 4290 /* 4291 * Unload a dlopened object and its dependencies from memory and from 4292 * our data structures. It is assumed that the DAG rooted in the 4293 * object has already been unreferenced, and that the object has a 4294 * reference count of 0. 4295 */ 4296 static void 4297 unload_object(Obj_Entry *root) 4298 { 4299 Obj_Entry *obj; 4300 Obj_Entry **linkp; 4301 4302 assert(root->refcount == 0); 4303 4304 /* 4305 * Pass over the DAG removing unreferenced objects from 4306 * appropriate lists. 4307 */ 4308 unlink_object(root); 4309 4310 /* Unmap all objects that are no longer referenced. */ 4311 linkp = &obj_list->next; 4312 while ((obj = *linkp) != NULL) { 4313 if (obj->refcount == 0) { 4314 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 4315 obj->path); 4316 dbg("unloading \"%s\"", obj->path); 4317 unload_filtees(root); 4318 munmap(obj->mapbase, obj->mapsize); 4319 linkmap_delete(obj); 4320 *linkp = obj->next; 4321 obj_count--; 4322 obj_free(obj); 4323 } else 4324 linkp = &obj->next; 4325 } 4326 obj_tail = linkp; 4327 } 4328 4329 static void 4330 unlink_object(Obj_Entry *root) 4331 { 4332 Objlist_Entry *elm; 4333 4334 if (root->refcount == 0) { 4335 /* Remove the object from the RTLD_GLOBAL list. */ 4336 objlist_remove(&list_global, root); 4337 4338 /* Remove the object from all objects' DAG lists. */ 4339 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4340 objlist_remove(&elm->obj->dldags, root); 4341 if (elm->obj != root) 4342 unlink_object(elm->obj); 4343 } 4344 } 4345 } 4346 4347 static void 4348 ref_dag(Obj_Entry *root) 4349 { 4350 Objlist_Entry *elm; 4351 4352 assert(root->dag_inited); 4353 STAILQ_FOREACH(elm, &root->dagmembers, link) 4354 elm->obj->refcount++; 4355 } 4356 4357 static void 4358 unref_dag(Obj_Entry *root) 4359 { 4360 Objlist_Entry *elm; 4361 4362 assert(root->dag_inited); 4363 STAILQ_FOREACH(elm, &root->dagmembers, link) 4364 elm->obj->refcount--; 4365 } 4366 4367 /* 4368 * Common code for MD __tls_get_addr(). 4369 */ 4370 void * 4371 tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset) 4372 { 4373 Elf_Addr* dtv = *dtvp; 4374 RtldLockState lockstate; 4375 4376 /* Check dtv generation in case new modules have arrived */ 4377 if (dtv[0] != tls_dtv_generation) { 4378 Elf_Addr* newdtv; 4379 int to_copy; 4380 4381 wlock_acquire(rtld_bind_lock, &lockstate); 4382 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4383 to_copy = dtv[1]; 4384 if (to_copy > tls_max_index) 4385 to_copy = tls_max_index; 4386 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4387 newdtv[0] = tls_dtv_generation; 4388 newdtv[1] = tls_max_index; 4389 free(dtv); 4390 lock_release(rtld_bind_lock, &lockstate); 4391 dtv = *dtvp = newdtv; 4392 } 4393 4394 /* Dynamically allocate module TLS if necessary */ 4395 if (!dtv[index + 1]) { 4396 /* Signal safe, wlock will block out signals. */ 4397 wlock_acquire(rtld_bind_lock, &lockstate); 4398 if (!dtv[index + 1]) 4399 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4400 lock_release(rtld_bind_lock, &lockstate); 4401 } 4402 return ((void *)(dtv[index + 1] + offset)); 4403 } 4404 4405 #if defined(RTLD_STATIC_TLS_VARIANT_II) 4406 4407 /* 4408 * Allocate the static TLS area. Return a pointer to the TCB. The 4409 * static area is based on negative offsets relative to the tcb. 4410 * 4411 * The TCB contains an errno pointer for the system call layer, but because 4412 * we are the RTLD we really have no idea how the caller was compiled so 4413 * the information has to be passed in. errno can either be: 4414 * 4415 * type 0 errno is a simple non-TLS global pointer. 4416 * (special case for e.g. libc_rtld) 4417 * type 1 errno accessed by GOT entry (dynamically linked programs) 4418 * type 2 errno accessed by %gs:OFFSET (statically linked programs) 4419 */ 4420 struct tls_tcb * 4421 allocate_tls(Obj_Entry *objs) 4422 { 4423 Obj_Entry *obj; 4424 size_t data_size; 4425 size_t dtv_size; 4426 struct tls_tcb *tcb; 4427 Elf_Addr *dtv; 4428 Elf_Addr addr; 4429 4430 /* 4431 * Allocate the new TCB. static TLS storage is placed just before the 4432 * TCB to support the %gs:OFFSET (negative offset) model. 4433 */ 4434 data_size = (tls_static_space + RTLD_STATIC_TLS_ALIGN_MASK) & 4435 ~RTLD_STATIC_TLS_ALIGN_MASK; 4436 tcb = malloc(data_size + sizeof(*tcb)); 4437 tcb = (void *)((char *)tcb + data_size); /* actual tcb location */ 4438 4439 dtv_size = (tls_max_index + 2) * sizeof(Elf_Addr); 4440 dtv = malloc(dtv_size); 4441 bzero(dtv, dtv_size); 4442 4443 #ifdef RTLD_TCB_HAS_SELF_POINTER 4444 tcb->tcb_self = tcb; 4445 #endif 4446 tcb->tcb_dtv = dtv; 4447 tcb->tcb_pthread = NULL; 4448 4449 dtv[0] = tls_dtv_generation; 4450 dtv[1] = tls_max_index; 4451 4452 for (obj = objs; obj; obj = obj->next) { 4453 if (obj->tlsoffset) { 4454 addr = (Elf_Addr)tcb - obj->tlsoffset; 4455 memset((void *)(addr + obj->tlsinitsize), 4456 0, obj->tlssize - obj->tlsinitsize); 4457 if (obj->tlsinit) 4458 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4459 dtv[obj->tlsindex + 1] = addr; 4460 } 4461 } 4462 return(tcb); 4463 } 4464 4465 void 4466 free_tls(struct tls_tcb *tcb) 4467 { 4468 Elf_Addr *dtv; 4469 int dtv_size, i; 4470 Elf_Addr tls_start, tls_end; 4471 size_t data_size; 4472 4473 data_size = (tls_static_space + RTLD_STATIC_TLS_ALIGN_MASK) & 4474 ~RTLD_STATIC_TLS_ALIGN_MASK; 4475 4476 dtv = tcb->tcb_dtv; 4477 dtv_size = dtv[1]; 4478 tls_end = (Elf_Addr)tcb; 4479 tls_start = (Elf_Addr)tcb - data_size; 4480 for (i = 0; i < dtv_size; i++) { 4481 if (dtv[i+2] != 0 && (dtv[i+2] < tls_start || dtv[i+2] > tls_end)) { 4482 free((void *)dtv[i+2]); 4483 } 4484 } 4485 free(dtv); 4486 4487 free((void*) tls_start); 4488 } 4489 4490 #else 4491 #error "Unsupported TLS layout" 4492 #endif 4493 4494 /* 4495 * Allocate TLS block for module with given index. 4496 */ 4497 void * 4498 allocate_module_tls(int index) 4499 { 4500 Obj_Entry* obj; 4501 char* p; 4502 4503 for (obj = obj_list; obj; obj = obj->next) { 4504 if (obj->tlsindex == index) 4505 break; 4506 } 4507 if (!obj) { 4508 _rtld_error("Can't find module with TLS index %d", index); 4509 die(); 4510 } 4511 4512 p = malloc(obj->tlssize); 4513 if (p == NULL) { 4514 _rtld_error("Cannot allocate TLS block for index %d", index); 4515 die(); 4516 } 4517 memcpy(p, obj->tlsinit, obj->tlsinitsize); 4518 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 4519 4520 return p; 4521 } 4522 4523 bool 4524 allocate_tls_offset(Obj_Entry *obj) 4525 { 4526 size_t off; 4527 4528 if (obj->tls_done) 4529 return true; 4530 4531 if (obj->tlssize == 0) { 4532 obj->tls_done = true; 4533 return true; 4534 } 4535 4536 if (obj->tlsindex == 1) 4537 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 4538 else 4539 off = calculate_tls_offset(tls_last_offset, tls_last_size, 4540 obj->tlssize, obj->tlsalign); 4541 4542 /* 4543 * If we have already fixed the size of the static TLS block, we 4544 * must stay within that size. When allocating the static TLS, we 4545 * leave a small amount of space spare to be used for dynamically 4546 * loading modules which use static TLS. 4547 */ 4548 if (tls_static_space) { 4549 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 4550 return false; 4551 } 4552 4553 tls_last_offset = obj->tlsoffset = off; 4554 tls_last_size = obj->tlssize; 4555 obj->tls_done = true; 4556 4557 return true; 4558 } 4559 4560 void 4561 free_tls_offset(Obj_Entry *obj) 4562 { 4563 #ifdef RTLD_STATIC_TLS_VARIANT_II 4564 /* 4565 * If we were the last thing to allocate out of the static TLS 4566 * block, we give our space back to the 'allocator'. This is a 4567 * simplistic workaround to allow libGL.so.1 to be loaded and 4568 * unloaded multiple times. We only handle the Variant II 4569 * mechanism for now - this really needs a proper allocator. 4570 */ 4571 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 4572 == calculate_tls_end(tls_last_offset, tls_last_size)) { 4573 tls_last_offset -= obj->tlssize; 4574 tls_last_size = 0; 4575 } 4576 #endif 4577 } 4578 4579 struct tls_tcb * 4580 _rtld_allocate_tls(void) 4581 { 4582 struct tls_tcb *new_tcb; 4583 RtldLockState lockstate; 4584 4585 wlock_acquire(rtld_bind_lock, &lockstate); 4586 new_tcb = allocate_tls(obj_list); 4587 lock_release(rtld_bind_lock, &lockstate); 4588 4589 return (new_tcb); 4590 } 4591 4592 void 4593 _rtld_free_tls(struct tls_tcb *tcb) 4594 { 4595 RtldLockState lockstate; 4596 4597 wlock_acquire(rtld_bind_lock, &lockstate); 4598 free_tls(tcb); 4599 lock_release(rtld_bind_lock, &lockstate); 4600 } 4601 4602 static void 4603 object_add_name(Obj_Entry *obj, const char *name) 4604 { 4605 Name_Entry *entry; 4606 size_t len; 4607 4608 len = strlen(name); 4609 entry = malloc(sizeof(Name_Entry) + len); 4610 4611 if (entry != NULL) { 4612 strcpy(entry->name, name); 4613 STAILQ_INSERT_TAIL(&obj->names, entry, link); 4614 } 4615 } 4616 4617 static int 4618 object_match_name(const Obj_Entry *obj, const char *name) 4619 { 4620 Name_Entry *entry; 4621 4622 STAILQ_FOREACH(entry, &obj->names, link) { 4623 if (strcmp(name, entry->name) == 0) 4624 return (1); 4625 } 4626 return (0); 4627 } 4628 4629 static Obj_Entry * 4630 locate_dependency(const Obj_Entry *obj, const char *name) 4631 { 4632 const Objlist_Entry *entry; 4633 const Needed_Entry *needed; 4634 4635 STAILQ_FOREACH(entry, &list_main, link) { 4636 if (object_match_name(entry->obj, name)) 4637 return entry->obj; 4638 } 4639 4640 for (needed = obj->needed; needed != NULL; needed = needed->next) { 4641 if (strcmp(obj->strtab + needed->name, name) == 0 || 4642 (needed->obj != NULL && object_match_name(needed->obj, name))) { 4643 /* 4644 * If there is DT_NEEDED for the name we are looking for, 4645 * we are all set. Note that object might not be found if 4646 * dependency was not loaded yet, so the function can 4647 * return NULL here. This is expected and handled 4648 * properly by the caller. 4649 */ 4650 return (needed->obj); 4651 } 4652 } 4653 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 4654 obj->path, name); 4655 die(); 4656 } 4657 4658 static int 4659 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 4660 const Elf_Vernaux *vna) 4661 { 4662 const Elf_Verdef *vd; 4663 const char *vername; 4664 4665 vername = refobj->strtab + vna->vna_name; 4666 vd = depobj->verdef; 4667 if (vd == NULL) { 4668 _rtld_error("%s: version %s required by %s not defined", 4669 depobj->path, vername, refobj->path); 4670 return (-1); 4671 } 4672 for (;;) { 4673 if (vd->vd_version != VER_DEF_CURRENT) { 4674 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4675 depobj->path, vd->vd_version); 4676 return (-1); 4677 } 4678 if (vna->vna_hash == vd->vd_hash) { 4679 const Elf_Verdaux *aux = (const Elf_Verdaux *) 4680 ((char *)vd + vd->vd_aux); 4681 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 4682 return (0); 4683 } 4684 if (vd->vd_next == 0) 4685 break; 4686 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4687 } 4688 if (vna->vna_flags & VER_FLG_WEAK) 4689 return (0); 4690 _rtld_error("%s: version %s required by %s not found", 4691 depobj->path, vername, refobj->path); 4692 return (-1); 4693 } 4694 4695 static int 4696 rtld_verify_object_versions(Obj_Entry *obj) 4697 { 4698 const Elf_Verneed *vn; 4699 const Elf_Verdef *vd; 4700 const Elf_Verdaux *vda; 4701 const Elf_Vernaux *vna; 4702 const Obj_Entry *depobj; 4703 int maxvernum, vernum; 4704 4705 if (obj->ver_checked) 4706 return (0); 4707 obj->ver_checked = true; 4708 4709 maxvernum = 0; 4710 /* 4711 * Walk over defined and required version records and figure out 4712 * max index used by any of them. Do very basic sanity checking 4713 * while there. 4714 */ 4715 vn = obj->verneed; 4716 while (vn != NULL) { 4717 if (vn->vn_version != VER_NEED_CURRENT) { 4718 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 4719 obj->path, vn->vn_version); 4720 return (-1); 4721 } 4722 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4723 for (;;) { 4724 vernum = VER_NEED_IDX(vna->vna_other); 4725 if (vernum > maxvernum) 4726 maxvernum = vernum; 4727 if (vna->vna_next == 0) 4728 break; 4729 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4730 } 4731 if (vn->vn_next == 0) 4732 break; 4733 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4734 } 4735 4736 vd = obj->verdef; 4737 while (vd != NULL) { 4738 if (vd->vd_version != VER_DEF_CURRENT) { 4739 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4740 obj->path, vd->vd_version); 4741 return (-1); 4742 } 4743 vernum = VER_DEF_IDX(vd->vd_ndx); 4744 if (vernum > maxvernum) 4745 maxvernum = vernum; 4746 if (vd->vd_next == 0) 4747 break; 4748 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4749 } 4750 4751 if (maxvernum == 0) 4752 return (0); 4753 4754 /* 4755 * Store version information in array indexable by version index. 4756 * Verify that object version requirements are satisfied along the 4757 * way. 4758 */ 4759 obj->vernum = maxvernum + 1; 4760 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 4761 4762 vd = obj->verdef; 4763 while (vd != NULL) { 4764 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 4765 vernum = VER_DEF_IDX(vd->vd_ndx); 4766 assert(vernum <= maxvernum); 4767 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 4768 obj->vertab[vernum].hash = vd->vd_hash; 4769 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 4770 obj->vertab[vernum].file = NULL; 4771 obj->vertab[vernum].flags = 0; 4772 } 4773 if (vd->vd_next == 0) 4774 break; 4775 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4776 } 4777 4778 vn = obj->verneed; 4779 while (vn != NULL) { 4780 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 4781 if (depobj == NULL) 4782 return (-1); 4783 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4784 for (;;) { 4785 if (check_object_provided_version(obj, depobj, vna)) 4786 return (-1); 4787 vernum = VER_NEED_IDX(vna->vna_other); 4788 assert(vernum <= maxvernum); 4789 obj->vertab[vernum].hash = vna->vna_hash; 4790 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 4791 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 4792 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 4793 VER_INFO_HIDDEN : 0; 4794 if (vna->vna_next == 0) 4795 break; 4796 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4797 } 4798 if (vn->vn_next == 0) 4799 break; 4800 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4801 } 4802 return 0; 4803 } 4804 4805 static int 4806 rtld_verify_versions(const Objlist *objlist) 4807 { 4808 Objlist_Entry *entry; 4809 int rc; 4810 4811 rc = 0; 4812 STAILQ_FOREACH(entry, objlist, link) { 4813 /* 4814 * Skip dummy objects or objects that have their version requirements 4815 * already checked. 4816 */ 4817 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 4818 continue; 4819 if (rtld_verify_object_versions(entry->obj) == -1) { 4820 rc = -1; 4821 if (ld_tracing == NULL) 4822 break; 4823 } 4824 } 4825 if (rc == 0 || ld_tracing != NULL) 4826 rc = rtld_verify_object_versions(&obj_rtld); 4827 return rc; 4828 } 4829 4830 const Ver_Entry * 4831 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 4832 { 4833 Elf_Versym vernum; 4834 4835 if (obj->vertab) { 4836 vernum = VER_NDX(obj->versyms[symnum]); 4837 if (vernum >= obj->vernum) { 4838 _rtld_error("%s: symbol %s has wrong verneed value %d", 4839 obj->path, obj->strtab + symnum, vernum); 4840 } else if (obj->vertab[vernum].hash != 0) { 4841 return &obj->vertab[vernum]; 4842 } 4843 } 4844 return NULL; 4845 } 4846 4847 int 4848 _rtld_get_stack_prot(void) 4849 { 4850 4851 return (stack_prot); 4852 } 4853 4854 static void 4855 map_stacks_exec(RtldLockState *lockstate) 4856 { 4857 return; 4858 /* 4859 * Stack protection must be implemented in the kernel before the dynamic 4860 * linker can handle PT_GNU_STACK sections. 4861 * The following is the FreeBSD implementation of map_stacks_exec() 4862 * void (*thr_map_stacks_exec)(void); 4863 * 4864 * if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 4865 * return; 4866 * thr_map_stacks_exec = (void (*)(void))(uintptr_t) 4867 * get_program_var_addr("__pthread_map_stacks_exec", lockstate); 4868 * if (thr_map_stacks_exec != NULL) { 4869 * stack_prot |= PROT_EXEC; 4870 * thr_map_stacks_exec(); 4871 * } 4872 */ 4873 } 4874 4875 void 4876 symlook_init(SymLook *dst, const char *name) 4877 { 4878 4879 bzero(dst, sizeof(*dst)); 4880 dst->name = name; 4881 dst->hash = elf_hash(name); 4882 dst->hash_gnu = gnu_hash(name); 4883 } 4884 4885 static void 4886 symlook_init_from_req(SymLook *dst, const SymLook *src) 4887 { 4888 4889 dst->name = src->name; 4890 dst->hash = src->hash; 4891 dst->hash_gnu = src->hash_gnu; 4892 dst->ventry = src->ventry; 4893 dst->flags = src->flags; 4894 dst->defobj_out = NULL; 4895 dst->sym_out = NULL; 4896 dst->lockstate = src->lockstate; 4897 } 4898 4899 4900 /* 4901 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 4902 */ 4903 static int 4904 parse_libdir(const char *str) 4905 { 4906 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 4907 const char *orig; 4908 int fd; 4909 char c; 4910 4911 orig = str; 4912 fd = 0; 4913 for (c = *str; c != '\0'; c = *++str) { 4914 if (c < '0' || c > '9') 4915 return (-1); 4916 4917 fd *= RADIX; 4918 fd += c - '0'; 4919 } 4920 4921 /* Make sure we actually parsed something. */ 4922 if (str == orig) { 4923 _rtld_error("failed to parse directory FD from '%s'", str); 4924 return (-1); 4925 } 4926 return (fd); 4927 } 4928 4929 #ifdef ENABLE_OSRELDATE 4930 /* 4931 * Overrides for libc_pic-provided functions. 4932 */ 4933 4934 int 4935 __getosreldate(void) 4936 { 4937 size_t len; 4938 int oid[2]; 4939 int error, osrel; 4940 4941 if (osreldate != 0) 4942 return (osreldate); 4943 4944 oid[0] = CTL_KERN; 4945 oid[1] = KERN_OSRELDATE; 4946 osrel = 0; 4947 len = sizeof(osrel); 4948 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 4949 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 4950 osreldate = osrel; 4951 return (osreldate); 4952 } 4953 #endif 4954 4955 /* 4956 * No unresolved symbols for rtld. 4957 */ 4958 void 4959 __pthread_cxa_finalize(struct dl_phdr_info *a) 4960 { 4961 } 4962 4963 const char * 4964 rtld_strerror(int errnum) 4965 { 4966 4967 if (errnum < 0 || errnum >= sys_nerr) 4968 return ("Unknown error"); 4969 return (sys_errlist[errnum]); 4970 } 4971