1 /*- 2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra. 3 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>. 4 * Copyright 2009, 2010, 2011 Konstantin Belousov <kib@FreeBSD.ORG>. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 * 27 * $FreeBSD$ 28 */ 29 30 /* 31 * Dynamic linker for ELF. 32 * 33 * John Polstra <jdp@polstra.com>. 34 */ 35 36 #ifndef __GNUC__ 37 #error "GCC is needed to compile this file" 38 #endif 39 40 #include <sys/param.h> 41 #include <sys/mount.h> 42 #include <sys/mman.h> 43 #include <sys/stat.h> 44 #include <sys/sysctl.h> 45 #include <sys/uio.h> 46 #include <sys/utsname.h> 47 #include <sys/ktrace.h> 48 49 #include <dlfcn.h> 50 #include <err.h> 51 #include <errno.h> 52 #include <fcntl.h> 53 #include <stdarg.h> 54 #include <stdio.h> 55 #include <stdlib.h> 56 #include <string.h> 57 #include <unistd.h> 58 59 #include "debug.h" 60 #include "rtld.h" 61 #include "libmap.h" 62 #include "rtld_tls.h" 63 #include "rtld_printf.h" 64 #include "notes.h" 65 66 #ifndef COMPAT_32BIT 67 #define PATH_RTLD "/libexec/ld-elf.so.1" 68 #else 69 #define PATH_RTLD "/libexec/ld-elf32.so.1" 70 #endif 71 72 /* Types. */ 73 typedef void (*func_ptr_type)(); 74 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 75 76 /* 77 * Function declarations. 78 */ 79 static const char *basename(const char *); 80 static void die(void) __dead2; 81 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 82 const Elf_Dyn **); 83 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *); 84 static void digest_dynamic(Obj_Entry *, int); 85 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 86 static Obj_Entry *dlcheck(void *); 87 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, 88 int lo_flags, int mode); 89 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 90 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 91 static bool donelist_check(DoneList *, const Obj_Entry *); 92 static void errmsg_restore(char *); 93 static char *errmsg_save(void); 94 static void *fill_search_info(const char *, size_t, void *); 95 static char *find_library(const char *, const Obj_Entry *); 96 static const char *gethints(void); 97 static void init_dag(Obj_Entry *); 98 static void init_rtld(caddr_t, Elf_Auxinfo **); 99 static void initlist_add_neededs(Needed_Entry *, Objlist *); 100 static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *); 101 static void linkmap_add(Obj_Entry *); 102 static void linkmap_delete(Obj_Entry *); 103 static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 104 static void unload_filtees(Obj_Entry *); 105 static int load_needed_objects(Obj_Entry *, int); 106 static int load_preload_objects(void); 107 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 108 static void map_stacks_exec(RtldLockState *); 109 static Obj_Entry *obj_from_addr(const void *); 110 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 111 static void objlist_call_init(Objlist *, RtldLockState *); 112 static void objlist_clear(Objlist *); 113 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 114 static void objlist_init(Objlist *); 115 static void objlist_push_head(Objlist *, Obj_Entry *); 116 static void objlist_push_tail(Objlist *, Obj_Entry *); 117 static void objlist_remove(Objlist *, Obj_Entry *); 118 static void *path_enumerate(const char *, path_enum_proc, void *); 119 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, RtldLockState *); 120 static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now, 121 RtldLockState *lockstate); 122 static int rtld_dirname(const char *, char *); 123 static int rtld_dirname_abs(const char *, char *); 124 static void *rtld_dlopen(const char *name, int fd, int mode); 125 static void rtld_exit(void); 126 static char *search_library_path(const char *, const char *); 127 static const void **get_program_var_addr(const char *, RtldLockState *); 128 static void set_program_var(const char *, const void *); 129 static int symlook_default(SymLook *, const Obj_Entry *refobj); 130 static int symlook_global(SymLook *, DoneList *); 131 static void symlook_init_from_req(SymLook *, const SymLook *); 132 static int symlook_list(SymLook *, const Objlist *, DoneList *); 133 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 134 static int symlook_obj1(SymLook *, const Obj_Entry *); 135 static void trace_loaded_objects(Obj_Entry *); 136 static void unlink_object(Obj_Entry *); 137 static void unload_object(Obj_Entry *); 138 static void unref_dag(Obj_Entry *); 139 static void ref_dag(Obj_Entry *); 140 static int origin_subst_one(char **, const char *, const char *, 141 const char *, char *); 142 static char *origin_subst(const char *, const char *); 143 static void preinit_main(void); 144 static int rtld_verify_versions(const Objlist *); 145 static int rtld_verify_object_versions(Obj_Entry *); 146 static void object_add_name(Obj_Entry *, const char *); 147 static int object_match_name(const Obj_Entry *, const char *); 148 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 149 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 150 struct dl_phdr_info *phdr_info); 151 152 void r_debug_state(struct r_debug *, struct link_map *) __noinline; 153 154 /* 155 * Data declarations. 156 */ 157 static char *error_message; /* Message for dlerror(), or NULL */ 158 struct r_debug r_debug; /* for GDB; */ 159 static bool libmap_disable; /* Disable libmap */ 160 static bool ld_loadfltr; /* Immediate filters processing */ 161 static char *libmap_override; /* Maps to use in addition to libmap.conf */ 162 static bool trust; /* False for setuid and setgid programs */ 163 static bool dangerous_ld_env; /* True if environment variables have been 164 used to affect the libraries loaded */ 165 static char *ld_bind_now; /* Environment variable for immediate binding */ 166 static char *ld_debug; /* Environment variable for debugging */ 167 static char *ld_library_path; /* Environment variable for search path */ 168 static char *ld_preload; /* Environment variable for libraries to 169 load first */ 170 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 171 static char *ld_tracing; /* Called from ldd to print libs */ 172 static char *ld_utrace; /* Use utrace() to log events. */ 173 static Obj_Entry *obj_list; /* Head of linked list of shared objects */ 174 static Obj_Entry **obj_tail; /* Link field of last object in list */ 175 static Obj_Entry *obj_main; /* The main program shared object */ 176 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 177 static unsigned int obj_count; /* Number of objects in obj_list */ 178 static unsigned int obj_loads; /* Number of objects in obj_list */ 179 180 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 181 STAILQ_HEAD_INITIALIZER(list_global); 182 static Objlist list_main = /* Objects loaded at program startup */ 183 STAILQ_HEAD_INITIALIZER(list_main); 184 static Objlist list_fini = /* Objects needing fini() calls */ 185 STAILQ_HEAD_INITIALIZER(list_fini); 186 187 Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 188 189 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 190 191 extern Elf_Dyn _DYNAMIC; 192 #pragma weak _DYNAMIC 193 #ifndef RTLD_IS_DYNAMIC 194 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL) 195 #endif 196 197 int osreldate, pagesize; 198 199 long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0}; 200 201 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 202 static int max_stack_flags; 203 204 /* 205 * Global declarations normally provided by crt1. The dynamic linker is 206 * not built with crt1, so we have to provide them ourselves. 207 */ 208 char *__progname; 209 char **environ; 210 211 /* 212 * Used to pass argc, argv to init functions. 213 */ 214 int main_argc; 215 char **main_argv; 216 217 /* 218 * Globals to control TLS allocation. 219 */ 220 size_t tls_last_offset; /* Static TLS offset of last module */ 221 size_t tls_last_size; /* Static TLS size of last module */ 222 size_t tls_static_space; /* Static TLS space allocated */ 223 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 224 int tls_max_index = 1; /* Largest module index allocated */ 225 226 /* 227 * Fill in a DoneList with an allocation large enough to hold all of 228 * the currently-loaded objects. Keep this as a macro since it calls 229 * alloca and we want that to occur within the scope of the caller. 230 */ 231 #define donelist_init(dlp) \ 232 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 233 assert((dlp)->objs != NULL), \ 234 (dlp)->num_alloc = obj_count, \ 235 (dlp)->num_used = 0) 236 237 #define UTRACE_DLOPEN_START 1 238 #define UTRACE_DLOPEN_STOP 2 239 #define UTRACE_DLCLOSE_START 3 240 #define UTRACE_DLCLOSE_STOP 4 241 #define UTRACE_LOAD_OBJECT 5 242 #define UTRACE_UNLOAD_OBJECT 6 243 #define UTRACE_ADD_RUNDEP 7 244 #define UTRACE_PRELOAD_FINISHED 8 245 #define UTRACE_INIT_CALL 9 246 #define UTRACE_FINI_CALL 10 247 248 struct utrace_rtld { 249 char sig[4]; /* 'RTLD' */ 250 int event; 251 void *handle; 252 void *mapbase; /* Used for 'parent' and 'init/fini' */ 253 size_t mapsize; 254 int refcnt; /* Used for 'mode' */ 255 char name[MAXPATHLEN]; 256 }; 257 258 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 259 if (ld_utrace != NULL) \ 260 ld_utrace_log(e, h, mb, ms, r, n); \ 261 } while (0) 262 263 static void 264 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 265 int refcnt, const char *name) 266 { 267 struct utrace_rtld ut; 268 269 ut.sig[0] = 'R'; 270 ut.sig[1] = 'T'; 271 ut.sig[2] = 'L'; 272 ut.sig[3] = 'D'; 273 ut.event = event; 274 ut.handle = handle; 275 ut.mapbase = mapbase; 276 ut.mapsize = mapsize; 277 ut.refcnt = refcnt; 278 bzero(ut.name, sizeof(ut.name)); 279 if (name) 280 strlcpy(ut.name, name, sizeof(ut.name)); 281 utrace(&ut, sizeof(ut)); 282 } 283 284 /* 285 * Main entry point for dynamic linking. The first argument is the 286 * stack pointer. The stack is expected to be laid out as described 287 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 288 * Specifically, the stack pointer points to a word containing 289 * ARGC. Following that in the stack is a null-terminated sequence 290 * of pointers to argument strings. Then comes a null-terminated 291 * sequence of pointers to environment strings. Finally, there is a 292 * sequence of "auxiliary vector" entries. 293 * 294 * The second argument points to a place to store the dynamic linker's 295 * exit procedure pointer and the third to a place to store the main 296 * program's object. 297 * 298 * The return value is the main program's entry point. 299 */ 300 func_ptr_type 301 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 302 { 303 Elf_Auxinfo *aux_info[AT_COUNT]; 304 int i; 305 int argc; 306 char **argv; 307 char **env; 308 Elf_Auxinfo *aux; 309 Elf_Auxinfo *auxp; 310 const char *argv0; 311 Objlist_Entry *entry; 312 Obj_Entry *obj; 313 Obj_Entry **preload_tail; 314 Objlist initlist; 315 RtldLockState lockstate; 316 int mib[2]; 317 size_t len; 318 319 /* 320 * On entry, the dynamic linker itself has not been relocated yet. 321 * Be very careful not to reference any global data until after 322 * init_rtld has returned. It is OK to reference file-scope statics 323 * and string constants, and to call static and global functions. 324 */ 325 326 /* Find the auxiliary vector on the stack. */ 327 argc = *sp++; 328 argv = (char **) sp; 329 sp += argc + 1; /* Skip over arguments and NULL terminator */ 330 env = (char **) sp; 331 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 332 ; 333 aux = (Elf_Auxinfo *) sp; 334 335 /* Digest the auxiliary vector. */ 336 for (i = 0; i < AT_COUNT; i++) 337 aux_info[i] = NULL; 338 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 339 if (auxp->a_type < AT_COUNT) 340 aux_info[auxp->a_type] = auxp; 341 } 342 343 /* Initialize and relocate ourselves. */ 344 assert(aux_info[AT_BASE] != NULL); 345 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 346 347 __progname = obj_rtld.path; 348 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 349 environ = env; 350 main_argc = argc; 351 main_argv = argv; 352 353 if (aux_info[AT_CANARY]->a_un.a_ptr != NULL) { 354 i = aux_info[AT_CANARYLEN]->a_un.a_val; 355 if (i > sizeof(__stack_chk_guard)) 356 i = sizeof(__stack_chk_guard); 357 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i); 358 } else { 359 mib[0] = CTL_KERN; 360 mib[1] = KERN_ARND; 361 362 len = sizeof(__stack_chk_guard); 363 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 || 364 len != sizeof(__stack_chk_guard)) { 365 /* If sysctl was unsuccessful, use the "terminator canary". */ 366 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0; 367 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0; 368 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n'; 369 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255; 370 } 371 } 372 373 trust = !issetugid(); 374 375 ld_bind_now = getenv(LD_ "BIND_NOW"); 376 /* 377 * If the process is tainted, then we un-set the dangerous environment 378 * variables. The process will be marked as tainted until setuid(2) 379 * is called. If any child process calls setuid(2) we do not want any 380 * future processes to honor the potentially un-safe variables. 381 */ 382 if (!trust) { 383 if (unsetenv(LD_ "PRELOAD") || unsetenv(LD_ "LIBMAP") || 384 unsetenv(LD_ "LIBRARY_PATH") || unsetenv(LD_ "LIBMAP_DISABLE") || 385 unsetenv(LD_ "DEBUG") || unsetenv(LD_ "ELF_HINTS_PATH") || 386 unsetenv(LD_ "LOADFLTR")) { 387 _rtld_error("environment corrupt; aborting"); 388 die(); 389 } 390 } 391 ld_debug = getenv(LD_ "DEBUG"); 392 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL; 393 libmap_override = getenv(LD_ "LIBMAP"); 394 ld_library_path = getenv(LD_ "LIBRARY_PATH"); 395 ld_preload = getenv(LD_ "PRELOAD"); 396 ld_elf_hints_path = getenv(LD_ "ELF_HINTS_PATH"); 397 ld_loadfltr = getenv(LD_ "LOADFLTR") != NULL; 398 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 399 (ld_library_path != NULL) || (ld_preload != NULL) || 400 (ld_elf_hints_path != NULL) || ld_loadfltr; 401 ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS"); 402 ld_utrace = getenv(LD_ "UTRACE"); 403 404 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 405 ld_elf_hints_path = _PATH_ELF_HINTS; 406 407 if (ld_debug != NULL && *ld_debug != '\0') 408 debug = 1; 409 dbg("%s is initialized, base address = %p", __progname, 410 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 411 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 412 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 413 414 dbg("initializing thread locks"); 415 lockdflt_init(); 416 417 /* 418 * Load the main program, or process its program header if it is 419 * already loaded. 420 */ 421 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */ 422 int fd = aux_info[AT_EXECFD]->a_un.a_val; 423 dbg("loading main program"); 424 obj_main = map_object(fd, argv0, NULL); 425 close(fd); 426 if (obj_main == NULL) 427 die(); 428 max_stack_flags = obj->stack_flags; 429 } else { /* Main program already loaded. */ 430 const Elf_Phdr *phdr; 431 int phnum; 432 caddr_t entry; 433 434 dbg("processing main program's program header"); 435 assert(aux_info[AT_PHDR] != NULL); 436 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 437 assert(aux_info[AT_PHNUM] != NULL); 438 phnum = aux_info[AT_PHNUM]->a_un.a_val; 439 assert(aux_info[AT_PHENT] != NULL); 440 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 441 assert(aux_info[AT_ENTRY] != NULL); 442 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 443 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL) 444 die(); 445 } 446 447 if (aux_info[AT_EXECPATH] != 0) { 448 char *kexecpath; 449 char buf[MAXPATHLEN]; 450 451 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 452 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 453 if (kexecpath[0] == '/') 454 obj_main->path = kexecpath; 455 else if (getcwd(buf, sizeof(buf)) == NULL || 456 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 457 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 458 obj_main->path = xstrdup(argv0); 459 else 460 obj_main->path = xstrdup(buf); 461 } else { 462 dbg("No AT_EXECPATH"); 463 obj_main->path = xstrdup(argv0); 464 } 465 dbg("obj_main path %s", obj_main->path); 466 obj_main->mainprog = true; 467 468 if (aux_info[AT_STACKPROT] != NULL && 469 aux_info[AT_STACKPROT]->a_un.a_val != 0) 470 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 471 472 /* 473 * Get the actual dynamic linker pathname from the executable if 474 * possible. (It should always be possible.) That ensures that 475 * gdb will find the right dynamic linker even if a non-standard 476 * one is being used. 477 */ 478 if (obj_main->interp != NULL && 479 strcmp(obj_main->interp, obj_rtld.path) != 0) { 480 free(obj_rtld.path); 481 obj_rtld.path = xstrdup(obj_main->interp); 482 __progname = obj_rtld.path; 483 } 484 485 digest_dynamic(obj_main, 0); 486 487 linkmap_add(obj_main); 488 linkmap_add(&obj_rtld); 489 490 /* Link the main program into the list of objects. */ 491 *obj_tail = obj_main; 492 obj_tail = &obj_main->next; 493 obj_count++; 494 obj_loads++; 495 496 /* Initialize a fake symbol for resolving undefined weak references. */ 497 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 498 sym_zero.st_shndx = SHN_UNDEF; 499 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 500 501 if (!libmap_disable) 502 libmap_disable = (bool)lm_init(libmap_override); 503 504 dbg("loading LD_PRELOAD libraries"); 505 if (load_preload_objects() == -1) 506 die(); 507 preload_tail = obj_tail; 508 509 dbg("loading needed objects"); 510 if (load_needed_objects(obj_main, 0) == -1) 511 die(); 512 513 /* Make a list of all objects loaded at startup. */ 514 for (obj = obj_list; obj != NULL; obj = obj->next) { 515 objlist_push_tail(&list_main, obj); 516 obj->refcount++; 517 } 518 519 dbg("checking for required versions"); 520 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 521 die(); 522 523 if (ld_tracing) { /* We're done */ 524 trace_loaded_objects(obj_main); 525 exit(0); 526 } 527 528 if (getenv(LD_ "DUMP_REL_PRE") != NULL) { 529 dump_relocations(obj_main); 530 exit (0); 531 } 532 533 /* 534 * Processing tls relocations requires having the tls offsets 535 * initialized. Prepare offsets before starting initial 536 * relocation processing. 537 */ 538 dbg("initializing initial thread local storage offsets"); 539 STAILQ_FOREACH(entry, &list_main, link) { 540 /* 541 * Allocate all the initial objects out of the static TLS 542 * block even if they didn't ask for it. 543 */ 544 allocate_tls_offset(entry->obj); 545 } 546 547 if (relocate_objects(obj_main, 548 ld_bind_now != NULL && *ld_bind_now != '\0', &obj_rtld, NULL) == -1) 549 die(); 550 551 dbg("doing copy relocations"); 552 if (do_copy_relocations(obj_main) == -1) 553 die(); 554 555 if (getenv(LD_ "DUMP_REL_POST") != NULL) { 556 dump_relocations(obj_main); 557 exit (0); 558 } 559 560 /* 561 * Setup TLS for main thread. This must be done after the 562 * relocations are processed, since tls initialization section 563 * might be the subject for relocations. 564 */ 565 dbg("initializing initial thread local storage"); 566 allocate_initial_tls(obj_list); 567 568 dbg("initializing key program variables"); 569 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 570 set_program_var("environ", env); 571 set_program_var("__elf_aux_vector", aux); 572 573 /* Make a list of init functions to call. */ 574 objlist_init(&initlist); 575 initlist_add_objects(obj_list, preload_tail, &initlist); 576 577 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 578 579 map_stacks_exec(NULL); 580 581 dbg("resolving ifuncs"); 582 if (resolve_objects_ifunc(obj_main, 583 ld_bind_now != NULL && *ld_bind_now != '\0', NULL) == -1) 584 die(); 585 586 if (!obj_main->crt_no_init) { 587 /* 588 * Make sure we don't call the main program's init and fini 589 * functions for binaries linked with old crt1 which calls 590 * _init itself. 591 */ 592 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 593 obj_main->preinit_array = obj_main->init_array = 594 obj_main->fini_array = (Elf_Addr)NULL; 595 } 596 597 wlock_acquire(rtld_bind_lock, &lockstate); 598 if (obj_main->crt_no_init) 599 preinit_main(); 600 objlist_call_init(&initlist, &lockstate); 601 objlist_clear(&initlist); 602 dbg("loading filtees"); 603 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 604 if (ld_loadfltr || obj->z_loadfltr) 605 load_filtees(obj, 0, &lockstate); 606 } 607 lock_release(rtld_bind_lock, &lockstate); 608 609 dbg("transferring control to program entry point = %p", obj_main->entry); 610 611 /* Return the exit procedure and the program entry point. */ 612 *exit_proc = rtld_exit; 613 *objp = obj_main; 614 return (func_ptr_type) obj_main->entry; 615 } 616 617 void * 618 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 619 { 620 void *ptr; 621 Elf_Addr target; 622 623 ptr = (void *)make_function_pointer(def, obj); 624 target = ((Elf_Addr (*)(void))ptr)(); 625 return ((void *)target); 626 } 627 628 Elf_Addr 629 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 630 { 631 const Elf_Rel *rel; 632 const Elf_Sym *def; 633 const Obj_Entry *defobj; 634 Elf_Addr *where; 635 Elf_Addr target; 636 RtldLockState lockstate; 637 638 rlock_acquire(rtld_bind_lock, &lockstate); 639 if (sigsetjmp(lockstate.env, 0) != 0) 640 lock_upgrade(rtld_bind_lock, &lockstate); 641 if (obj->pltrel) 642 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 643 else 644 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 645 646 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 647 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL, 648 &lockstate); 649 if (def == NULL) 650 die(); 651 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 652 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 653 else 654 target = (Elf_Addr)(defobj->relocbase + def->st_value); 655 656 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 657 defobj->strtab + def->st_name, basename(obj->path), 658 (void *)target, basename(defobj->path)); 659 660 /* 661 * Write the new contents for the jmpslot. Note that depending on 662 * architecture, the value which we need to return back to the 663 * lazy binding trampoline may or may not be the target 664 * address. The value returned from reloc_jmpslot() is the value 665 * that the trampoline needs. 666 */ 667 target = reloc_jmpslot(where, target, defobj, obj, rel); 668 lock_release(rtld_bind_lock, &lockstate); 669 return target; 670 } 671 672 /* 673 * Error reporting function. Use it like printf. If formats the message 674 * into a buffer, and sets things up so that the next call to dlerror() 675 * will return the message. 676 */ 677 void 678 _rtld_error(const char *fmt, ...) 679 { 680 static char buf[512]; 681 va_list ap; 682 683 va_start(ap, fmt); 684 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 685 error_message = buf; 686 va_end(ap); 687 } 688 689 /* 690 * Return a dynamically-allocated copy of the current error message, if any. 691 */ 692 static char * 693 errmsg_save(void) 694 { 695 return error_message == NULL ? NULL : xstrdup(error_message); 696 } 697 698 /* 699 * Restore the current error message from a copy which was previously saved 700 * by errmsg_save(). The copy is freed. 701 */ 702 static void 703 errmsg_restore(char *saved_msg) 704 { 705 if (saved_msg == NULL) 706 error_message = NULL; 707 else { 708 _rtld_error("%s", saved_msg); 709 free(saved_msg); 710 } 711 } 712 713 static const char * 714 basename(const char *name) 715 { 716 const char *p = strrchr(name, '/'); 717 return p != NULL ? p + 1 : name; 718 } 719 720 static struct utsname uts; 721 722 static int 723 origin_subst_one(char **res, const char *real, const char *kw, const char *subst, 724 char *may_free) 725 { 726 const char *p, *p1; 727 char *res1; 728 int subst_len; 729 int kw_len; 730 731 res1 = *res = NULL; 732 p = real; 733 subst_len = kw_len = 0; 734 for (;;) { 735 p1 = strstr(p, kw); 736 if (p1 != NULL) { 737 if (subst_len == 0) { 738 subst_len = strlen(subst); 739 kw_len = strlen(kw); 740 } 741 if (*res == NULL) { 742 *res = xmalloc(PATH_MAX); 743 res1 = *res; 744 } 745 if ((res1 - *res) + subst_len + (p1 - p) >= PATH_MAX) { 746 _rtld_error("Substitution of %s in %s cannot be performed", 747 kw, real); 748 if (may_free != NULL) 749 free(may_free); 750 free(res); 751 return (false); 752 } 753 memcpy(res1, p, p1 - p); 754 res1 += p1 - p; 755 memcpy(res1, subst, subst_len); 756 res1 += subst_len; 757 p = p1 + kw_len; 758 } else { 759 if (*res == NULL) { 760 if (may_free != NULL) 761 *res = may_free; 762 else 763 *res = xstrdup(real); 764 return (true); 765 } 766 *res1 = '\0'; 767 if (may_free != NULL) 768 free(may_free); 769 if (strlcat(res1, p, PATH_MAX - (res1 - *res)) >= PATH_MAX) { 770 free(res); 771 return (false); 772 } 773 return (true); 774 } 775 } 776 } 777 778 static char * 779 origin_subst(const char *real, const char *origin_path) 780 { 781 char *res1, *res2, *res3, *res4; 782 783 if (uts.sysname[0] == '\0') { 784 if (uname(&uts) != 0) { 785 _rtld_error("utsname failed: %d", errno); 786 return (NULL); 787 } 788 } 789 if (!origin_subst_one(&res1, real, "$ORIGIN", origin_path, NULL) || 790 !origin_subst_one(&res2, res1, "$OSNAME", uts.sysname, res1) || 791 !origin_subst_one(&res3, res2, "$OSREL", uts.release, res2) || 792 !origin_subst_one(&res4, res3, "$PLATFORM", uts.machine, res3)) 793 return (NULL); 794 return (res4); 795 } 796 797 static void 798 die(void) 799 { 800 const char *msg = dlerror(); 801 802 if (msg == NULL) 803 msg = "Fatal error"; 804 rtld_fdputstr(STDERR_FILENO, msg); 805 rtld_fdputchar(STDERR_FILENO, '\n'); 806 _exit(1); 807 } 808 809 /* 810 * Process a shared object's DYNAMIC section, and save the important 811 * information in its Obj_Entry structure. 812 */ 813 static void 814 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 815 const Elf_Dyn **dyn_soname) 816 { 817 const Elf_Dyn *dynp; 818 Needed_Entry **needed_tail = &obj->needed; 819 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 820 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 821 int plttype = DT_REL; 822 823 *dyn_rpath = NULL; 824 *dyn_soname = NULL; 825 826 obj->bind_now = false; 827 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 828 switch (dynp->d_tag) { 829 830 case DT_REL: 831 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 832 break; 833 834 case DT_RELSZ: 835 obj->relsize = dynp->d_un.d_val; 836 break; 837 838 case DT_RELENT: 839 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 840 break; 841 842 case DT_JMPREL: 843 obj->pltrel = (const Elf_Rel *) 844 (obj->relocbase + dynp->d_un.d_ptr); 845 break; 846 847 case DT_PLTRELSZ: 848 obj->pltrelsize = dynp->d_un.d_val; 849 break; 850 851 case DT_RELA: 852 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 853 break; 854 855 case DT_RELASZ: 856 obj->relasize = dynp->d_un.d_val; 857 break; 858 859 case DT_RELAENT: 860 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 861 break; 862 863 case DT_PLTREL: 864 plttype = dynp->d_un.d_val; 865 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 866 break; 867 868 case DT_SYMTAB: 869 obj->symtab = (const Elf_Sym *) 870 (obj->relocbase + dynp->d_un.d_ptr); 871 break; 872 873 case DT_SYMENT: 874 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 875 break; 876 877 case DT_STRTAB: 878 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 879 break; 880 881 case DT_STRSZ: 882 obj->strsize = dynp->d_un.d_val; 883 break; 884 885 case DT_VERNEED: 886 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 887 dynp->d_un.d_val); 888 break; 889 890 case DT_VERNEEDNUM: 891 obj->verneednum = dynp->d_un.d_val; 892 break; 893 894 case DT_VERDEF: 895 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 896 dynp->d_un.d_val); 897 break; 898 899 case DT_VERDEFNUM: 900 obj->verdefnum = dynp->d_un.d_val; 901 break; 902 903 case DT_VERSYM: 904 obj->versyms = (const Elf_Versym *)(obj->relocbase + 905 dynp->d_un.d_val); 906 break; 907 908 case DT_HASH: 909 { 910 const Elf_Hashelt *hashtab = (const Elf_Hashelt *) 911 (obj->relocbase + dynp->d_un.d_ptr); 912 obj->nbuckets = hashtab[0]; 913 obj->nchains = hashtab[1]; 914 obj->buckets = hashtab + 2; 915 obj->chains = obj->buckets + obj->nbuckets; 916 } 917 break; 918 919 case DT_NEEDED: 920 if (!obj->rtld) { 921 Needed_Entry *nep = NEW(Needed_Entry); 922 nep->name = dynp->d_un.d_val; 923 nep->obj = NULL; 924 nep->next = NULL; 925 926 *needed_tail = nep; 927 needed_tail = &nep->next; 928 } 929 break; 930 931 case DT_FILTER: 932 if (!obj->rtld) { 933 Needed_Entry *nep = NEW(Needed_Entry); 934 nep->name = dynp->d_un.d_val; 935 nep->obj = NULL; 936 nep->next = NULL; 937 938 *needed_filtees_tail = nep; 939 needed_filtees_tail = &nep->next; 940 } 941 break; 942 943 case DT_AUXILIARY: 944 if (!obj->rtld) { 945 Needed_Entry *nep = NEW(Needed_Entry); 946 nep->name = dynp->d_un.d_val; 947 nep->obj = NULL; 948 nep->next = NULL; 949 950 *needed_aux_filtees_tail = nep; 951 needed_aux_filtees_tail = &nep->next; 952 } 953 break; 954 955 case DT_PLTGOT: 956 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 957 break; 958 959 case DT_TEXTREL: 960 obj->textrel = true; 961 break; 962 963 case DT_SYMBOLIC: 964 obj->symbolic = true; 965 break; 966 967 case DT_RPATH: 968 case DT_RUNPATH: /* XXX: process separately */ 969 /* 970 * We have to wait until later to process this, because we 971 * might not have gotten the address of the string table yet. 972 */ 973 *dyn_rpath = dynp; 974 break; 975 976 case DT_SONAME: 977 *dyn_soname = dynp; 978 break; 979 980 case DT_INIT: 981 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 982 break; 983 984 case DT_PREINIT_ARRAY: 985 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 986 break; 987 988 case DT_PREINIT_ARRAYSZ: 989 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 990 break; 991 992 case DT_INIT_ARRAY: 993 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 994 break; 995 996 case DT_INIT_ARRAYSZ: 997 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 998 break; 999 1000 case DT_FINI: 1001 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1002 break; 1003 1004 case DT_FINI_ARRAY: 1005 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1006 break; 1007 1008 case DT_FINI_ARRAYSZ: 1009 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1010 break; 1011 1012 /* 1013 * Don't process DT_DEBUG on MIPS as the dynamic section 1014 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1015 */ 1016 1017 #ifndef __mips__ 1018 case DT_DEBUG: 1019 /* XXX - not implemented yet */ 1020 if (!early) 1021 dbg("Filling in DT_DEBUG entry"); 1022 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 1023 break; 1024 #endif 1025 1026 case DT_FLAGS: 1027 if ((dynp->d_un.d_val & DF_ORIGIN) && trust) 1028 obj->z_origin = true; 1029 if (dynp->d_un.d_val & DF_SYMBOLIC) 1030 obj->symbolic = true; 1031 if (dynp->d_un.d_val & DF_TEXTREL) 1032 obj->textrel = true; 1033 if (dynp->d_un.d_val & DF_BIND_NOW) 1034 obj->bind_now = true; 1035 /*if (dynp->d_un.d_val & DF_STATIC_TLS) 1036 ;*/ 1037 break; 1038 #ifdef __mips__ 1039 case DT_MIPS_LOCAL_GOTNO: 1040 obj->local_gotno = dynp->d_un.d_val; 1041 break; 1042 1043 case DT_MIPS_SYMTABNO: 1044 obj->symtabno = dynp->d_un.d_val; 1045 break; 1046 1047 case DT_MIPS_GOTSYM: 1048 obj->gotsym = dynp->d_un.d_val; 1049 break; 1050 1051 case DT_MIPS_RLD_MAP: 1052 #ifdef notyet 1053 if (!early) 1054 dbg("Filling in DT_DEBUG entry"); 1055 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 1056 #endif 1057 break; 1058 #endif 1059 1060 case DT_FLAGS_1: 1061 if (dynp->d_un.d_val & DF_1_NOOPEN) 1062 obj->z_noopen = true; 1063 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust) 1064 obj->z_origin = true; 1065 /*if (dynp->d_un.d_val & DF_1_GLOBAL) 1066 XXX ;*/ 1067 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1068 obj->bind_now = true; 1069 if (dynp->d_un.d_val & DF_1_NODELETE) 1070 obj->z_nodelete = true; 1071 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1072 obj->z_loadfltr = true; 1073 break; 1074 1075 default: 1076 if (!early) { 1077 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1078 (long)dynp->d_tag); 1079 } 1080 break; 1081 } 1082 } 1083 1084 obj->traced = false; 1085 1086 if (plttype == DT_RELA) { 1087 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1088 obj->pltrel = NULL; 1089 obj->pltrelasize = obj->pltrelsize; 1090 obj->pltrelsize = 0; 1091 } 1092 } 1093 1094 static void 1095 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1096 const Elf_Dyn *dyn_soname) 1097 { 1098 1099 if (obj->z_origin && obj->origin_path == NULL) { 1100 obj->origin_path = xmalloc(PATH_MAX); 1101 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1) 1102 die(); 1103 } 1104 1105 if (dyn_rpath != NULL) { 1106 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 1107 if (obj->z_origin) 1108 obj->rpath = origin_subst(obj->rpath, obj->origin_path); 1109 } 1110 1111 if (dyn_soname != NULL) 1112 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1113 } 1114 1115 static void 1116 digest_dynamic(Obj_Entry *obj, int early) 1117 { 1118 const Elf_Dyn *dyn_rpath; 1119 const Elf_Dyn *dyn_soname; 1120 1121 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname); 1122 digest_dynamic2(obj, dyn_rpath, dyn_soname); 1123 } 1124 1125 /* 1126 * Process a shared object's program header. This is used only for the 1127 * main program, when the kernel has already loaded the main program 1128 * into memory before calling the dynamic linker. It creates and 1129 * returns an Obj_Entry structure. 1130 */ 1131 static Obj_Entry * 1132 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1133 { 1134 Obj_Entry *obj; 1135 const Elf_Phdr *phlimit = phdr + phnum; 1136 const Elf_Phdr *ph; 1137 Elf_Addr note_start, note_end; 1138 int nsegs = 0; 1139 1140 obj = obj_new(); 1141 for (ph = phdr; ph < phlimit; ph++) { 1142 if (ph->p_type != PT_PHDR) 1143 continue; 1144 1145 obj->phdr = phdr; 1146 obj->phsize = ph->p_memsz; 1147 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1148 break; 1149 } 1150 1151 obj->stack_flags = PF_X | PF_R | PF_W; 1152 1153 for (ph = phdr; ph < phlimit; ph++) { 1154 switch (ph->p_type) { 1155 1156 case PT_INTERP: 1157 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1158 break; 1159 1160 case PT_LOAD: 1161 if (nsegs == 0) { /* First load segment */ 1162 obj->vaddrbase = trunc_page(ph->p_vaddr); 1163 obj->mapbase = obj->vaddrbase + obj->relocbase; 1164 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1165 obj->vaddrbase; 1166 } else { /* Last load segment */ 1167 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1168 obj->vaddrbase; 1169 } 1170 nsegs++; 1171 break; 1172 1173 case PT_DYNAMIC: 1174 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1175 break; 1176 1177 case PT_TLS: 1178 obj->tlsindex = 1; 1179 obj->tlssize = ph->p_memsz; 1180 obj->tlsalign = ph->p_align; 1181 obj->tlsinitsize = ph->p_filesz; 1182 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1183 break; 1184 1185 case PT_GNU_STACK: 1186 obj->stack_flags = ph->p_flags; 1187 break; 1188 1189 case PT_GNU_RELRO: 1190 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1191 obj->relro_size = round_page(ph->p_memsz); 1192 break; 1193 1194 case PT_NOTE: 1195 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1196 note_end = note_start + ph->p_filesz; 1197 digest_notes(obj, note_start, note_end); 1198 break; 1199 } 1200 } 1201 if (nsegs < 1) { 1202 _rtld_error("%s: too few PT_LOAD segments", path); 1203 return NULL; 1204 } 1205 1206 obj->entry = entry; 1207 return obj; 1208 } 1209 1210 void 1211 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1212 { 1213 const Elf_Note *note; 1214 const char *note_name; 1215 uintptr_t p; 1216 1217 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1218 note = (const Elf_Note *)((const char *)(note + 1) + 1219 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1220 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1221 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1222 note->n_descsz != sizeof(int32_t)) 1223 continue; 1224 if (note->n_type != ABI_NOTETYPE && 1225 note->n_type != CRT_NOINIT_NOTETYPE) 1226 continue; 1227 note_name = (const char *)(note + 1); 1228 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1229 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1230 continue; 1231 switch (note->n_type) { 1232 case ABI_NOTETYPE: 1233 /* FreeBSD osrel note */ 1234 p = (uintptr_t)(note + 1); 1235 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1236 obj->osrel = *(const int32_t *)(p); 1237 dbg("note osrel %d", obj->osrel); 1238 break; 1239 case CRT_NOINIT_NOTETYPE: 1240 /* FreeBSD 'crt does not call init' note */ 1241 obj->crt_no_init = true; 1242 dbg("note crt_no_init"); 1243 break; 1244 } 1245 } 1246 } 1247 1248 static Obj_Entry * 1249 dlcheck(void *handle) 1250 { 1251 Obj_Entry *obj; 1252 1253 for (obj = obj_list; obj != NULL; obj = obj->next) 1254 if (obj == (Obj_Entry *) handle) 1255 break; 1256 1257 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1258 _rtld_error("Invalid shared object handle %p", handle); 1259 return NULL; 1260 } 1261 return obj; 1262 } 1263 1264 /* 1265 * If the given object is already in the donelist, return true. Otherwise 1266 * add the object to the list and return false. 1267 */ 1268 static bool 1269 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1270 { 1271 unsigned int i; 1272 1273 for (i = 0; i < dlp->num_used; i++) 1274 if (dlp->objs[i] == obj) 1275 return true; 1276 /* 1277 * Our donelist allocation should always be sufficient. But if 1278 * our threads locking isn't working properly, more shared objects 1279 * could have been loaded since we allocated the list. That should 1280 * never happen, but we'll handle it properly just in case it does. 1281 */ 1282 if (dlp->num_used < dlp->num_alloc) 1283 dlp->objs[dlp->num_used++] = obj; 1284 return false; 1285 } 1286 1287 /* 1288 * Hash function for symbol table lookup. Don't even think about changing 1289 * this. It is specified by the System V ABI. 1290 */ 1291 unsigned long 1292 elf_hash(const char *name) 1293 { 1294 const unsigned char *p = (const unsigned char *) name; 1295 unsigned long h = 0; 1296 unsigned long g; 1297 1298 while (*p != '\0') { 1299 h = (h << 4) + *p++; 1300 if ((g = h & 0xf0000000) != 0) 1301 h ^= g >> 24; 1302 h &= ~g; 1303 } 1304 return h; 1305 } 1306 1307 /* 1308 * Find the library with the given name, and return its full pathname. 1309 * The returned string is dynamically allocated. Generates an error 1310 * message and returns NULL if the library cannot be found. 1311 * 1312 * If the second argument is non-NULL, then it refers to an already- 1313 * loaded shared object, whose library search path will be searched. 1314 * 1315 * The search order is: 1316 * LD_LIBRARY_PATH 1317 * rpath in the referencing file 1318 * ldconfig hints 1319 * /lib:/usr/lib 1320 */ 1321 static char * 1322 find_library(const char *xname, const Obj_Entry *refobj) 1323 { 1324 char *pathname; 1325 char *name; 1326 1327 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */ 1328 if (xname[0] != '/' && !trust) { 1329 _rtld_error("Absolute pathname required for shared object \"%s\"", 1330 xname); 1331 return NULL; 1332 } 1333 if (refobj != NULL && refobj->z_origin) 1334 return origin_subst(xname, refobj->origin_path); 1335 else 1336 return xstrdup(xname); 1337 } 1338 1339 if (libmap_disable || (refobj == NULL) || 1340 (name = lm_find(refobj->path, xname)) == NULL) 1341 name = (char *)xname; 1342 1343 dbg(" Searching for \"%s\"", name); 1344 1345 if ((pathname = search_library_path(name, ld_library_path)) != NULL || 1346 (refobj != NULL && 1347 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1348 (pathname = search_library_path(name, gethints())) != NULL || 1349 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL) 1350 return pathname; 1351 1352 if(refobj != NULL && refobj->path != NULL) { 1353 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 1354 name, basename(refobj->path)); 1355 } else { 1356 _rtld_error("Shared object \"%s\" not found", name); 1357 } 1358 return NULL; 1359 } 1360 1361 /* 1362 * Given a symbol number in a referencing object, find the corresponding 1363 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1364 * no definition was found. Returns a pointer to the Obj_Entry of the 1365 * defining object via the reference parameter DEFOBJ_OUT. 1366 */ 1367 const Elf_Sym * 1368 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1369 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1370 RtldLockState *lockstate) 1371 { 1372 const Elf_Sym *ref; 1373 const Elf_Sym *def; 1374 const Obj_Entry *defobj; 1375 SymLook req; 1376 const char *name; 1377 int res; 1378 1379 /* 1380 * If we have already found this symbol, get the information from 1381 * the cache. 1382 */ 1383 if (symnum >= refobj->nchains) 1384 return NULL; /* Bad object */ 1385 if (cache != NULL && cache[symnum].sym != NULL) { 1386 *defobj_out = cache[symnum].obj; 1387 return cache[symnum].sym; 1388 } 1389 1390 ref = refobj->symtab + symnum; 1391 name = refobj->strtab + ref->st_name; 1392 def = NULL; 1393 defobj = NULL; 1394 1395 /* 1396 * We don't have to do a full scale lookup if the symbol is local. 1397 * We know it will bind to the instance in this load module; to 1398 * which we already have a pointer (ie ref). By not doing a lookup, 1399 * we not only improve performance, but it also avoids unresolvable 1400 * symbols when local symbols are not in the hash table. This has 1401 * been seen with the ia64 toolchain. 1402 */ 1403 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1404 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1405 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1406 symnum); 1407 } 1408 symlook_init(&req, name); 1409 req.flags = flags; 1410 req.ventry = fetch_ventry(refobj, symnum); 1411 req.lockstate = lockstate; 1412 res = symlook_default(&req, refobj); 1413 if (res == 0) { 1414 def = req.sym_out; 1415 defobj = req.defobj_out; 1416 } 1417 } else { 1418 def = ref; 1419 defobj = refobj; 1420 } 1421 1422 /* 1423 * If we found no definition and the reference is weak, treat the 1424 * symbol as having the value zero. 1425 */ 1426 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1427 def = &sym_zero; 1428 defobj = obj_main; 1429 } 1430 1431 if (def != NULL) { 1432 *defobj_out = defobj; 1433 /* Record the information in the cache to avoid subsequent lookups. */ 1434 if (cache != NULL) { 1435 cache[symnum].sym = def; 1436 cache[symnum].obj = defobj; 1437 } 1438 } else { 1439 if (refobj != &obj_rtld) 1440 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name); 1441 } 1442 return def; 1443 } 1444 1445 /* 1446 * Return the search path from the ldconfig hints file, reading it if 1447 * necessary. Returns NULL if there are problems with the hints file, 1448 * or if the search path there is empty. 1449 */ 1450 static const char * 1451 gethints(void) 1452 { 1453 static char *hints; 1454 1455 if (hints == NULL) { 1456 int fd; 1457 struct elfhints_hdr hdr; 1458 char *p; 1459 1460 /* Keep from trying again in case the hints file is bad. */ 1461 hints = ""; 1462 1463 if ((fd = open(ld_elf_hints_path, O_RDONLY)) == -1) 1464 return NULL; 1465 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1466 hdr.magic != ELFHINTS_MAGIC || 1467 hdr.version != 1) { 1468 close(fd); 1469 return NULL; 1470 } 1471 p = xmalloc(hdr.dirlistlen + 1); 1472 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1473 read(fd, p, hdr.dirlistlen + 1) != (ssize_t)hdr.dirlistlen + 1) { 1474 free(p); 1475 close(fd); 1476 return NULL; 1477 } 1478 hints = p; 1479 close(fd); 1480 } 1481 return hints[0] != '\0' ? hints : NULL; 1482 } 1483 1484 static void 1485 init_dag(Obj_Entry *root) 1486 { 1487 const Needed_Entry *needed; 1488 const Objlist_Entry *elm; 1489 DoneList donelist; 1490 1491 if (root->dag_inited) 1492 return; 1493 donelist_init(&donelist); 1494 1495 /* Root object belongs to own DAG. */ 1496 objlist_push_tail(&root->dldags, root); 1497 objlist_push_tail(&root->dagmembers, root); 1498 donelist_check(&donelist, root); 1499 1500 /* 1501 * Add dependencies of root object to DAG in breadth order 1502 * by exploiting the fact that each new object get added 1503 * to the tail of the dagmembers list. 1504 */ 1505 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1506 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1507 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1508 continue; 1509 objlist_push_tail(&needed->obj->dldags, root); 1510 objlist_push_tail(&root->dagmembers, needed->obj); 1511 } 1512 } 1513 root->dag_inited = true; 1514 } 1515 1516 /* 1517 * Initialize the dynamic linker. The argument is the address at which 1518 * the dynamic linker has been mapped into memory. The primary task of 1519 * this function is to relocate the dynamic linker. 1520 */ 1521 static void 1522 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 1523 { 1524 Obj_Entry objtmp; /* Temporary rtld object */ 1525 const Elf_Dyn *dyn_rpath; 1526 const Elf_Dyn *dyn_soname; 1527 1528 /* 1529 * Conjure up an Obj_Entry structure for the dynamic linker. 1530 * 1531 * The "path" member can't be initialized yet because string constants 1532 * cannot yet be accessed. Below we will set it correctly. 1533 */ 1534 memset(&objtmp, 0, sizeof(objtmp)); 1535 objtmp.path = NULL; 1536 objtmp.rtld = true; 1537 objtmp.mapbase = mapbase; 1538 #ifdef PIC 1539 objtmp.relocbase = mapbase; 1540 #endif 1541 if (RTLD_IS_DYNAMIC()) { 1542 objtmp.dynamic = rtld_dynamic(&objtmp); 1543 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname); 1544 assert(objtmp.needed == NULL); 1545 #if !defined(__mips__) 1546 /* MIPS has a bogus DT_TEXTREL. */ 1547 assert(!objtmp.textrel); 1548 #endif 1549 1550 /* 1551 * Temporarily put the dynamic linker entry into the object list, so 1552 * that symbols can be found. 1553 */ 1554 1555 relocate_objects(&objtmp, true, &objtmp, NULL); 1556 } 1557 1558 /* Initialize the object list. */ 1559 obj_tail = &obj_list; 1560 1561 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1562 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1563 1564 if (aux_info[AT_PAGESZ] != NULL) 1565 pagesize = aux_info[AT_PAGESZ]->a_un.a_val; 1566 if (aux_info[AT_OSRELDATE] != NULL) 1567 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 1568 1569 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname); 1570 1571 /* Replace the path with a dynamically allocated copy. */ 1572 obj_rtld.path = xstrdup(PATH_RTLD); 1573 1574 r_debug.r_brk = r_debug_state; 1575 r_debug.r_state = RT_CONSISTENT; 1576 } 1577 1578 /* 1579 * Add the init functions from a needed object list (and its recursive 1580 * needed objects) to "list". This is not used directly; it is a helper 1581 * function for initlist_add_objects(). The write lock must be held 1582 * when this function is called. 1583 */ 1584 static void 1585 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 1586 { 1587 /* Recursively process the successor needed objects. */ 1588 if (needed->next != NULL) 1589 initlist_add_neededs(needed->next, list); 1590 1591 /* Process the current needed object. */ 1592 if (needed->obj != NULL) 1593 initlist_add_objects(needed->obj, &needed->obj->next, list); 1594 } 1595 1596 /* 1597 * Scan all of the DAGs rooted in the range of objects from "obj" to 1598 * "tail" and add their init functions to "list". This recurses over 1599 * the DAGs and ensure the proper init ordering such that each object's 1600 * needed libraries are initialized before the object itself. At the 1601 * same time, this function adds the objects to the global finalization 1602 * list "list_fini" in the opposite order. The write lock must be 1603 * held when this function is called. 1604 */ 1605 static void 1606 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list) 1607 { 1608 if (obj->init_scanned || obj->init_done) 1609 return; 1610 obj->init_scanned = true; 1611 1612 /* Recursively process the successor objects. */ 1613 if (&obj->next != tail) 1614 initlist_add_objects(obj->next, tail, list); 1615 1616 /* Recursively process the needed objects. */ 1617 if (obj->needed != NULL) 1618 initlist_add_neededs(obj->needed, list); 1619 1620 /* Add the object to the init list. */ 1621 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL || 1622 obj->init_array != (Elf_Addr)NULL) 1623 objlist_push_tail(list, obj); 1624 1625 /* Add the object to the global fini list in the reverse order. */ 1626 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 1627 && !obj->on_fini_list) { 1628 objlist_push_head(&list_fini, obj); 1629 obj->on_fini_list = true; 1630 } 1631 } 1632 1633 #ifndef FPTR_TARGET 1634 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 1635 #endif 1636 1637 static void 1638 free_needed_filtees(Needed_Entry *n) 1639 { 1640 Needed_Entry *needed, *needed1; 1641 1642 for (needed = n; needed != NULL; needed = needed->next) { 1643 if (needed->obj != NULL) { 1644 dlclose(needed->obj); 1645 needed->obj = NULL; 1646 } 1647 } 1648 for (needed = n; needed != NULL; needed = needed1) { 1649 needed1 = needed->next; 1650 free(needed); 1651 } 1652 } 1653 1654 static void 1655 unload_filtees(Obj_Entry *obj) 1656 { 1657 1658 free_needed_filtees(obj->needed_filtees); 1659 obj->needed_filtees = NULL; 1660 free_needed_filtees(obj->needed_aux_filtees); 1661 obj->needed_aux_filtees = NULL; 1662 obj->filtees_loaded = false; 1663 } 1664 1665 static void 1666 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags) 1667 { 1668 1669 for (; needed != NULL; needed = needed->next) { 1670 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 1671 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 1672 RTLD_LOCAL); 1673 } 1674 } 1675 1676 static void 1677 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 1678 { 1679 1680 lock_restart_for_upgrade(lockstate); 1681 if (!obj->filtees_loaded) { 1682 load_filtee1(obj, obj->needed_filtees, flags); 1683 load_filtee1(obj, obj->needed_aux_filtees, flags); 1684 obj->filtees_loaded = true; 1685 } 1686 } 1687 1688 static int 1689 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 1690 { 1691 Obj_Entry *obj1; 1692 1693 for (; needed != NULL; needed = needed->next) { 1694 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 1695 flags & ~RTLD_LO_NOLOAD); 1696 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 1697 return (-1); 1698 if (obj1 != NULL && obj1->z_nodelete && !obj1->ref_nodel) { 1699 dbg("obj %s nodelete", obj1->path); 1700 init_dag(obj1); 1701 ref_dag(obj1); 1702 obj1->ref_nodel = true; 1703 } 1704 } 1705 return (0); 1706 } 1707 1708 /* 1709 * Given a shared object, traverse its list of needed objects, and load 1710 * each of them. Returns 0 on success. Generates an error message and 1711 * returns -1 on failure. 1712 */ 1713 static int 1714 load_needed_objects(Obj_Entry *first, int flags) 1715 { 1716 Obj_Entry *obj; 1717 1718 for (obj = first; obj != NULL; obj = obj->next) { 1719 if (process_needed(obj, obj->needed, flags) == -1) 1720 return (-1); 1721 } 1722 return (0); 1723 } 1724 1725 static int 1726 load_preload_objects(void) 1727 { 1728 char *p = ld_preload; 1729 static const char delim[] = " \t:;"; 1730 1731 if (p == NULL) 1732 return 0; 1733 1734 p += strspn(p, delim); 1735 while (*p != '\0') { 1736 size_t len = strcspn(p, delim); 1737 char savech; 1738 1739 savech = p[len]; 1740 p[len] = '\0'; 1741 if (load_object(p, -1, NULL, 0) == NULL) 1742 return -1; /* XXX - cleanup */ 1743 p[len] = savech; 1744 p += len; 1745 p += strspn(p, delim); 1746 } 1747 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 1748 return 0; 1749 } 1750 1751 static const char * 1752 printable_path(const char *path) 1753 { 1754 1755 return (path == NULL ? "<unknown>" : path); 1756 } 1757 1758 /* 1759 * Load a shared object into memory, if it is not already loaded. The 1760 * object may be specified by name or by user-supplied file descriptor 1761 * fd_u. In the later case, the fd_u descriptor is not closed, but its 1762 * duplicate is. 1763 * 1764 * Returns a pointer to the Obj_Entry for the object. Returns NULL 1765 * on failure. 1766 */ 1767 static Obj_Entry * 1768 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 1769 { 1770 Obj_Entry *obj; 1771 int fd; 1772 struct stat sb; 1773 char *path; 1774 1775 if (name != NULL) { 1776 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 1777 if (object_match_name(obj, name)) 1778 return (obj); 1779 } 1780 1781 path = find_library(name, refobj); 1782 if (path == NULL) 1783 return (NULL); 1784 } else 1785 path = NULL; 1786 1787 /* 1788 * If we didn't find a match by pathname, or the name is not 1789 * supplied, open the file and check again by device and inode. 1790 * This avoids false mismatches caused by multiple links or ".." 1791 * in pathnames. 1792 * 1793 * To avoid a race, we open the file and use fstat() rather than 1794 * using stat(). 1795 */ 1796 fd = -1; 1797 if (fd_u == -1) { 1798 if ((fd = open(path, O_RDONLY)) == -1) { 1799 _rtld_error("Cannot open \"%s\"", path); 1800 free(path); 1801 return (NULL); 1802 } 1803 } else { 1804 fd = dup(fd_u); 1805 if (fd == -1) { 1806 _rtld_error("Cannot dup fd"); 1807 free(path); 1808 return (NULL); 1809 } 1810 } 1811 if (fstat(fd, &sb) == -1) { 1812 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 1813 close(fd); 1814 free(path); 1815 return NULL; 1816 } 1817 for (obj = obj_list->next; obj != NULL; obj = obj->next) 1818 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 1819 break; 1820 if (obj != NULL && name != NULL) { 1821 object_add_name(obj, name); 1822 free(path); 1823 close(fd); 1824 return obj; 1825 } 1826 if (flags & RTLD_LO_NOLOAD) { 1827 free(path); 1828 close(fd); 1829 return (NULL); 1830 } 1831 1832 /* First use of this object, so we must map it in */ 1833 obj = do_load_object(fd, name, path, &sb, flags); 1834 if (obj == NULL) 1835 free(path); 1836 close(fd); 1837 1838 return obj; 1839 } 1840 1841 static Obj_Entry * 1842 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 1843 int flags) 1844 { 1845 Obj_Entry *obj; 1846 struct statfs fs; 1847 1848 /* 1849 * but first, make sure that environment variables haven't been 1850 * used to circumvent the noexec flag on a filesystem. 1851 */ 1852 if (dangerous_ld_env) { 1853 if (fstatfs(fd, &fs) != 0) { 1854 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 1855 return NULL; 1856 } 1857 if (fs.f_flags & MNT_NOEXEC) { 1858 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 1859 return NULL; 1860 } 1861 } 1862 dbg("loading \"%s\"", printable_path(path)); 1863 obj = map_object(fd, printable_path(path), sbp); 1864 if (obj == NULL) 1865 return NULL; 1866 1867 /* 1868 * If DT_SONAME is present in the object, digest_dynamic2 already 1869 * added it to the object names. 1870 */ 1871 if (name != NULL) 1872 object_add_name(obj, name); 1873 obj->path = path; 1874 digest_dynamic(obj, 0); 1875 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 1876 RTLD_LO_DLOPEN) { 1877 dbg("refusing to load non-loadable \"%s\"", obj->path); 1878 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 1879 munmap(obj->mapbase, obj->mapsize); 1880 obj_free(obj); 1881 return (NULL); 1882 } 1883 1884 *obj_tail = obj; 1885 obj_tail = &obj->next; 1886 obj_count++; 1887 obj_loads++; 1888 linkmap_add(obj); /* for GDB & dlinfo() */ 1889 max_stack_flags |= obj->stack_flags; 1890 1891 dbg(" %p .. %p: %s", obj->mapbase, 1892 obj->mapbase + obj->mapsize - 1, obj->path); 1893 if (obj->textrel) 1894 dbg(" WARNING: %s has impure text", obj->path); 1895 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 1896 obj->path); 1897 1898 return obj; 1899 } 1900 1901 static Obj_Entry * 1902 obj_from_addr(const void *addr) 1903 { 1904 Obj_Entry *obj; 1905 1906 for (obj = obj_list; obj != NULL; obj = obj->next) { 1907 if (addr < (void *) obj->mapbase) 1908 continue; 1909 if (addr < (void *) (obj->mapbase + obj->mapsize)) 1910 return obj; 1911 } 1912 return NULL; 1913 } 1914 1915 static void 1916 preinit_main(void) 1917 { 1918 Elf_Addr *preinit_addr; 1919 int index; 1920 1921 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 1922 if (preinit_addr == NULL) 1923 return; 1924 1925 for (index = 0; index < obj_main->preinit_array_num; index++) { 1926 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 1927 dbg("calling preinit function for %s at %p", obj_main->path, 1928 (void *)preinit_addr[index]); 1929 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 1930 0, 0, obj_main->path); 1931 call_init_pointer(obj_main, preinit_addr[index]); 1932 } 1933 } 1934 } 1935 1936 /* 1937 * Call the finalization functions for each of the objects in "list" 1938 * belonging to the DAG of "root" and referenced once. If NULL "root" 1939 * is specified, every finalization function will be called regardless 1940 * of the reference count and the list elements won't be freed. All of 1941 * the objects are expected to have non-NULL fini functions. 1942 */ 1943 static void 1944 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 1945 { 1946 Objlist_Entry *elm; 1947 char *saved_msg; 1948 Elf_Addr *fini_addr; 1949 int index; 1950 1951 assert(root == NULL || root->refcount == 1); 1952 1953 /* 1954 * Preserve the current error message since a fini function might 1955 * call into the dynamic linker and overwrite it. 1956 */ 1957 saved_msg = errmsg_save(); 1958 do { 1959 STAILQ_FOREACH(elm, list, link) { 1960 if (root != NULL && (elm->obj->refcount != 1 || 1961 objlist_find(&root->dagmembers, elm->obj) == NULL)) 1962 continue; 1963 /* Remove object from fini list to prevent recursive invocation. */ 1964 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 1965 /* 1966 * XXX: If a dlopen() call references an object while the 1967 * fini function is in progress, we might end up trying to 1968 * unload the referenced object in dlclose() or the object 1969 * won't be unloaded although its fini function has been 1970 * called. 1971 */ 1972 lock_release(rtld_bind_lock, lockstate); 1973 1974 /* 1975 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 1976 * When this happens, DT_FINI_ARRAY is processed first. 1977 */ 1978 fini_addr = (Elf_Addr *)elm->obj->fini_array; 1979 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 1980 for (index = elm->obj->fini_array_num - 1; index >= 0; 1981 index--) { 1982 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 1983 dbg("calling fini function for %s at %p", 1984 elm->obj->path, (void *)fini_addr[index]); 1985 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 1986 (void *)fini_addr[index], 0, 0, elm->obj->path); 1987 call_initfini_pointer(elm->obj, fini_addr[index]); 1988 } 1989 } 1990 } 1991 if (elm->obj->fini != (Elf_Addr)NULL) { 1992 dbg("calling fini function for %s at %p", elm->obj->path, 1993 (void *)elm->obj->fini); 1994 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 1995 0, 0, elm->obj->path); 1996 call_initfini_pointer(elm->obj, elm->obj->fini); 1997 } 1998 wlock_acquire(rtld_bind_lock, lockstate); 1999 /* No need to free anything if process is going down. */ 2000 if (root != NULL) 2001 free(elm); 2002 /* 2003 * We must restart the list traversal after every fini call 2004 * because a dlclose() call from the fini function or from 2005 * another thread might have modified the reference counts. 2006 */ 2007 break; 2008 } 2009 } while (elm != NULL); 2010 errmsg_restore(saved_msg); 2011 } 2012 2013 /* 2014 * Call the initialization functions for each of the objects in 2015 * "list". All of the objects are expected to have non-NULL init 2016 * functions. 2017 */ 2018 static void 2019 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2020 { 2021 Objlist_Entry *elm; 2022 Obj_Entry *obj; 2023 char *saved_msg; 2024 Elf_Addr *init_addr; 2025 int index; 2026 2027 /* 2028 * Clean init_scanned flag so that objects can be rechecked and 2029 * possibly initialized earlier if any of vectors called below 2030 * cause the change by using dlopen. 2031 */ 2032 for (obj = obj_list; obj != NULL; obj = obj->next) 2033 obj->init_scanned = false; 2034 2035 /* 2036 * Preserve the current error message since an init function might 2037 * call into the dynamic linker and overwrite it. 2038 */ 2039 saved_msg = errmsg_save(); 2040 STAILQ_FOREACH(elm, list, link) { 2041 if (elm->obj->init_done) /* Initialized early. */ 2042 continue; 2043 /* 2044 * Race: other thread might try to use this object before current 2045 * one completes the initilization. Not much can be done here 2046 * without better locking. 2047 */ 2048 elm->obj->init_done = true; 2049 lock_release(rtld_bind_lock, lockstate); 2050 2051 /* 2052 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2053 * When this happens, DT_INIT is processed first. 2054 */ 2055 if (elm->obj->init != (Elf_Addr)NULL) { 2056 dbg("calling init function for %s at %p", elm->obj->path, 2057 (void *)elm->obj->init); 2058 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2059 0, 0, elm->obj->path); 2060 call_initfini_pointer(elm->obj, elm->obj->init); 2061 } 2062 init_addr = (Elf_Addr *)elm->obj->init_array; 2063 if (init_addr != NULL) { 2064 for (index = 0; index < elm->obj->init_array_num; index++) { 2065 if (init_addr[index] != 0 && init_addr[index] != 1) { 2066 dbg("calling init function for %s at %p", elm->obj->path, 2067 (void *)init_addr[index]); 2068 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2069 (void *)init_addr[index], 0, 0, elm->obj->path); 2070 call_init_pointer(elm->obj, init_addr[index]); 2071 } 2072 } 2073 } 2074 wlock_acquire(rtld_bind_lock, lockstate); 2075 } 2076 errmsg_restore(saved_msg); 2077 } 2078 2079 static void 2080 objlist_clear(Objlist *list) 2081 { 2082 Objlist_Entry *elm; 2083 2084 while (!STAILQ_EMPTY(list)) { 2085 elm = STAILQ_FIRST(list); 2086 STAILQ_REMOVE_HEAD(list, link); 2087 free(elm); 2088 } 2089 } 2090 2091 static Objlist_Entry * 2092 objlist_find(Objlist *list, const Obj_Entry *obj) 2093 { 2094 Objlist_Entry *elm; 2095 2096 STAILQ_FOREACH(elm, list, link) 2097 if (elm->obj == obj) 2098 return elm; 2099 return NULL; 2100 } 2101 2102 static void 2103 objlist_init(Objlist *list) 2104 { 2105 STAILQ_INIT(list); 2106 } 2107 2108 static void 2109 objlist_push_head(Objlist *list, Obj_Entry *obj) 2110 { 2111 Objlist_Entry *elm; 2112 2113 elm = NEW(Objlist_Entry); 2114 elm->obj = obj; 2115 STAILQ_INSERT_HEAD(list, elm, link); 2116 } 2117 2118 static void 2119 objlist_push_tail(Objlist *list, Obj_Entry *obj) 2120 { 2121 Objlist_Entry *elm; 2122 2123 elm = NEW(Objlist_Entry); 2124 elm->obj = obj; 2125 STAILQ_INSERT_TAIL(list, elm, link); 2126 } 2127 2128 static void 2129 objlist_remove(Objlist *list, Obj_Entry *obj) 2130 { 2131 Objlist_Entry *elm; 2132 2133 if ((elm = objlist_find(list, obj)) != NULL) { 2134 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2135 free(elm); 2136 } 2137 } 2138 2139 /* 2140 * Relocate newly-loaded shared objects. The argument is a pointer to 2141 * the Obj_Entry for the first such object. All objects from the first 2142 * to the end of the list of objects are relocated. Returns 0 on success, 2143 * or -1 on failure. 2144 */ 2145 static int 2146 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2147 RtldLockState *lockstate) 2148 { 2149 Obj_Entry *obj; 2150 2151 for (obj = first; obj != NULL; obj = obj->next) { 2152 if (obj != rtldobj) 2153 dbg("relocating \"%s\"", obj->path); 2154 if (obj->nbuckets == 0 || obj->nchains == 0 || obj->buckets == NULL || 2155 obj->symtab == NULL || obj->strtab == NULL) { 2156 _rtld_error("%s: Shared object has no run-time symbol table", 2157 obj->path); 2158 return -1; 2159 } 2160 2161 if (obj->textrel) { 2162 /* There are relocations to the write-protected text segment. */ 2163 if (mprotect(obj->mapbase, obj->textsize, 2164 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) { 2165 _rtld_error("%s: Cannot write-enable text segment: %s", 2166 obj->path, strerror(errno)); 2167 return -1; 2168 } 2169 } 2170 2171 /* Process the non-PLT relocations. */ 2172 if (reloc_non_plt(obj, rtldobj, lockstate)) 2173 return -1; 2174 2175 if (obj->textrel) { /* Re-protected the text segment. */ 2176 if (mprotect(obj->mapbase, obj->textsize, 2177 PROT_READ|PROT_EXEC) == -1) { 2178 _rtld_error("%s: Cannot write-protect text segment: %s", 2179 obj->path, strerror(errno)); 2180 return -1; 2181 } 2182 } 2183 2184 2185 /* Set the special PLT or GOT entries. */ 2186 init_pltgot(obj); 2187 2188 /* Process the PLT relocations. */ 2189 if (reloc_plt(obj) == -1) 2190 return -1; 2191 /* Relocate the jump slots if we are doing immediate binding. */ 2192 if (obj->bind_now || bind_now) 2193 if (reloc_jmpslots(obj, lockstate) == -1) 2194 return -1; 2195 2196 if (obj->relro_size > 0) { 2197 if (mprotect(obj->relro_page, obj->relro_size, PROT_READ) == -1) { 2198 _rtld_error("%s: Cannot enforce relro protection: %s", 2199 obj->path, strerror(errno)); 2200 return -1; 2201 } 2202 } 2203 2204 /* 2205 * Set up the magic number and version in the Obj_Entry. These 2206 * were checked in the crt1.o from the original ElfKit, so we 2207 * set them for backward compatibility. 2208 */ 2209 obj->magic = RTLD_MAGIC; 2210 obj->version = RTLD_VERSION; 2211 } 2212 2213 return (0); 2214 } 2215 2216 /* 2217 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2218 * referencing STT_GNU_IFUNC symbols is postponed till the other 2219 * relocations are done. The indirect functions specified as 2220 * ifunc are allowed to call other symbols, so we need to have 2221 * objects relocated before asking for resolution from indirects. 2222 * 2223 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2224 * instead of the usual lazy handling of PLT slots. It is 2225 * consistent with how GNU does it. 2226 */ 2227 static int 2228 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, RtldLockState *lockstate) 2229 { 2230 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2231 return (-1); 2232 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2233 reloc_gnu_ifunc(obj, lockstate) == -1) 2234 return (-1); 2235 return (0); 2236 } 2237 2238 static int 2239 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, RtldLockState *lockstate) 2240 { 2241 Obj_Entry *obj; 2242 2243 for (obj = first; obj != NULL; obj = obj->next) { 2244 if (resolve_object_ifunc(obj, bind_now, lockstate) == -1) 2245 return (-1); 2246 } 2247 return (0); 2248 } 2249 2250 static int 2251 initlist_objects_ifunc(Objlist *list, bool bind_now, RtldLockState *lockstate) 2252 { 2253 Objlist_Entry *elm; 2254 2255 STAILQ_FOREACH(elm, list, link) { 2256 if (resolve_object_ifunc(elm->obj, bind_now, lockstate) == -1) 2257 return (-1); 2258 } 2259 return (0); 2260 } 2261 2262 /* 2263 * Cleanup procedure. It will be called (by the atexit mechanism) just 2264 * before the process exits. 2265 */ 2266 static void 2267 rtld_exit(void) 2268 { 2269 RtldLockState lockstate; 2270 2271 wlock_acquire(rtld_bind_lock, &lockstate); 2272 dbg("rtld_exit()"); 2273 objlist_call_fini(&list_fini, NULL, &lockstate); 2274 /* No need to remove the items from the list, since we are exiting. */ 2275 if (!libmap_disable) 2276 lm_fini(); 2277 lock_release(rtld_bind_lock, &lockstate); 2278 } 2279 2280 static void * 2281 path_enumerate(const char *path, path_enum_proc callback, void *arg) 2282 { 2283 #ifdef COMPAT_32BIT 2284 const char *trans; 2285 #endif 2286 if (path == NULL) 2287 return (NULL); 2288 2289 path += strspn(path, ":;"); 2290 while (*path != '\0') { 2291 size_t len; 2292 char *res; 2293 2294 len = strcspn(path, ":;"); 2295 #ifdef COMPAT_32BIT 2296 trans = lm_findn(NULL, path, len); 2297 if (trans) 2298 res = callback(trans, strlen(trans), arg); 2299 else 2300 #endif 2301 res = callback(path, len, arg); 2302 2303 if (res != NULL) 2304 return (res); 2305 2306 path += len; 2307 path += strspn(path, ":;"); 2308 } 2309 2310 return (NULL); 2311 } 2312 2313 struct try_library_args { 2314 const char *name; 2315 size_t namelen; 2316 char *buffer; 2317 size_t buflen; 2318 }; 2319 2320 static void * 2321 try_library_path(const char *dir, size_t dirlen, void *param) 2322 { 2323 struct try_library_args *arg; 2324 2325 arg = param; 2326 if (*dir == '/' || trust) { 2327 char *pathname; 2328 2329 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 2330 return (NULL); 2331 2332 pathname = arg->buffer; 2333 strncpy(pathname, dir, dirlen); 2334 pathname[dirlen] = '/'; 2335 strcpy(pathname + dirlen + 1, arg->name); 2336 2337 dbg(" Trying \"%s\"", pathname); 2338 if (access(pathname, F_OK) == 0) { /* We found it */ 2339 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 2340 strcpy(pathname, arg->buffer); 2341 return (pathname); 2342 } 2343 } 2344 return (NULL); 2345 } 2346 2347 static char * 2348 search_library_path(const char *name, const char *path) 2349 { 2350 char *p; 2351 struct try_library_args arg; 2352 2353 if (path == NULL) 2354 return NULL; 2355 2356 arg.name = name; 2357 arg.namelen = strlen(name); 2358 arg.buffer = xmalloc(PATH_MAX); 2359 arg.buflen = PATH_MAX; 2360 2361 p = path_enumerate(path, try_library_path, &arg); 2362 2363 free(arg.buffer); 2364 2365 return (p); 2366 } 2367 2368 int 2369 dlclose(void *handle) 2370 { 2371 Obj_Entry *root; 2372 RtldLockState lockstate; 2373 2374 wlock_acquire(rtld_bind_lock, &lockstate); 2375 root = dlcheck(handle); 2376 if (root == NULL) { 2377 lock_release(rtld_bind_lock, &lockstate); 2378 return -1; 2379 } 2380 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 2381 root->path); 2382 2383 /* Unreference the object and its dependencies. */ 2384 root->dl_refcount--; 2385 2386 if (root->refcount == 1) { 2387 /* 2388 * The object will be no longer referenced, so we must unload it. 2389 * First, call the fini functions. 2390 */ 2391 objlist_call_fini(&list_fini, root, &lockstate); 2392 2393 unref_dag(root); 2394 2395 /* Finish cleaning up the newly-unreferenced objects. */ 2396 GDB_STATE(RT_DELETE,&root->linkmap); 2397 unload_object(root); 2398 GDB_STATE(RT_CONSISTENT,NULL); 2399 } else 2400 unref_dag(root); 2401 2402 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 2403 lock_release(rtld_bind_lock, &lockstate); 2404 return 0; 2405 } 2406 2407 char * 2408 dlerror(void) 2409 { 2410 char *msg = error_message; 2411 error_message = NULL; 2412 return msg; 2413 } 2414 2415 /* 2416 * This function is deprecated and has no effect. 2417 */ 2418 void 2419 dllockinit(void *context, 2420 void *(*lock_create)(void *context), 2421 void (*rlock_acquire)(void *lock), 2422 void (*wlock_acquire)(void *lock), 2423 void (*lock_release)(void *lock), 2424 void (*lock_destroy)(void *lock), 2425 void (*context_destroy)(void *context)) 2426 { 2427 static void *cur_context; 2428 static void (*cur_context_destroy)(void *); 2429 2430 /* Just destroy the context from the previous call, if necessary. */ 2431 if (cur_context_destroy != NULL) 2432 cur_context_destroy(cur_context); 2433 cur_context = context; 2434 cur_context_destroy = context_destroy; 2435 } 2436 2437 void * 2438 dlopen(const char *name, int mode) 2439 { 2440 2441 return (rtld_dlopen(name, -1, mode)); 2442 } 2443 2444 void * 2445 fdlopen(int fd, int mode) 2446 { 2447 2448 return (rtld_dlopen(NULL, fd, mode)); 2449 } 2450 2451 static void * 2452 rtld_dlopen(const char *name, int fd, int mode) 2453 { 2454 RtldLockState lockstate; 2455 int lo_flags; 2456 2457 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 2458 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 2459 if (ld_tracing != NULL) { 2460 rlock_acquire(rtld_bind_lock, &lockstate); 2461 if (sigsetjmp(lockstate.env, 0) != 0) 2462 lock_upgrade(rtld_bind_lock, &lockstate); 2463 environ = (char **)*get_program_var_addr("environ", &lockstate); 2464 lock_release(rtld_bind_lock, &lockstate); 2465 } 2466 lo_flags = RTLD_LO_DLOPEN; 2467 if (mode & RTLD_NODELETE) 2468 lo_flags |= RTLD_LO_NODELETE; 2469 if (mode & RTLD_NOLOAD) 2470 lo_flags |= RTLD_LO_NOLOAD; 2471 if (ld_tracing != NULL) 2472 lo_flags |= RTLD_LO_TRACE; 2473 2474 return (dlopen_object(name, fd, obj_main, lo_flags, 2475 mode & (RTLD_MODEMASK | RTLD_GLOBAL))); 2476 } 2477 2478 static void 2479 dlopen_cleanup(Obj_Entry *obj) 2480 { 2481 2482 obj->dl_refcount--; 2483 unref_dag(obj); 2484 if (obj->refcount == 0) 2485 unload_object(obj); 2486 } 2487 2488 static Obj_Entry * 2489 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 2490 int mode) 2491 { 2492 Obj_Entry **old_obj_tail; 2493 Obj_Entry *obj; 2494 Objlist initlist; 2495 RtldLockState lockstate; 2496 int result; 2497 2498 objlist_init(&initlist); 2499 2500 wlock_acquire(rtld_bind_lock, &lockstate); 2501 GDB_STATE(RT_ADD,NULL); 2502 2503 old_obj_tail = obj_tail; 2504 obj = NULL; 2505 if (name == NULL && fd == -1) { 2506 obj = obj_main; 2507 obj->refcount++; 2508 } else { 2509 obj = load_object(name, fd, refobj, lo_flags); 2510 } 2511 2512 if (obj) { 2513 obj->dl_refcount++; 2514 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 2515 objlist_push_tail(&list_global, obj); 2516 if (*old_obj_tail != NULL) { /* We loaded something new. */ 2517 assert(*old_obj_tail == obj); 2518 result = load_needed_objects(obj, lo_flags & RTLD_LO_DLOPEN); 2519 init_dag(obj); 2520 ref_dag(obj); 2521 if (result != -1) 2522 result = rtld_verify_versions(&obj->dagmembers); 2523 if (result != -1 && ld_tracing) 2524 goto trace; 2525 if (result == -1 || (relocate_objects(obj, (mode & RTLD_MODEMASK) 2526 == RTLD_NOW, &obj_rtld, &lockstate)) == -1) { 2527 dlopen_cleanup(obj); 2528 obj = NULL; 2529 } else { 2530 /* Make list of init functions to call. */ 2531 initlist_add_objects(obj, &obj->next, &initlist); 2532 } 2533 } else { 2534 2535 /* 2536 * Bump the reference counts for objects on this DAG. If 2537 * this is the first dlopen() call for the object that was 2538 * already loaded as a dependency, initialize the dag 2539 * starting at it. 2540 */ 2541 init_dag(obj); 2542 ref_dag(obj); 2543 2544 if ((lo_flags & RTLD_LO_TRACE) != 0) 2545 goto trace; 2546 } 2547 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 2548 obj->z_nodelete) && !obj->ref_nodel) { 2549 dbg("obj %s nodelete", obj->path); 2550 ref_dag(obj); 2551 obj->z_nodelete = obj->ref_nodel = true; 2552 } 2553 } 2554 2555 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 2556 name); 2557 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 2558 2559 map_stacks_exec(&lockstate); 2560 2561 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 2562 &lockstate) == -1) { 2563 objlist_clear(&initlist); 2564 dlopen_cleanup(obj); 2565 lock_release(rtld_bind_lock, &lockstate); 2566 return (NULL); 2567 } 2568 2569 /* Call the init functions. */ 2570 objlist_call_init(&initlist, &lockstate); 2571 objlist_clear(&initlist); 2572 lock_release(rtld_bind_lock, &lockstate); 2573 return obj; 2574 trace: 2575 trace_loaded_objects(obj); 2576 lock_release(rtld_bind_lock, &lockstate); 2577 exit(0); 2578 } 2579 2580 static void * 2581 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 2582 int flags) 2583 { 2584 DoneList donelist; 2585 const Obj_Entry *obj, *defobj; 2586 const Elf_Sym *def; 2587 SymLook req; 2588 RtldLockState lockstate; 2589 int res; 2590 2591 def = NULL; 2592 defobj = NULL; 2593 symlook_init(&req, name); 2594 req.ventry = ve; 2595 req.flags = flags | SYMLOOK_IN_PLT; 2596 req.lockstate = &lockstate; 2597 2598 rlock_acquire(rtld_bind_lock, &lockstate); 2599 if (sigsetjmp(lockstate.env, 0) != 0) 2600 lock_upgrade(rtld_bind_lock, &lockstate); 2601 if (handle == NULL || handle == RTLD_NEXT || 2602 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 2603 2604 if ((obj = obj_from_addr(retaddr)) == NULL) { 2605 _rtld_error("Cannot determine caller's shared object"); 2606 lock_release(rtld_bind_lock, &lockstate); 2607 return NULL; 2608 } 2609 if (handle == NULL) { /* Just the caller's shared object. */ 2610 res = symlook_obj(&req, obj); 2611 if (res == 0) { 2612 def = req.sym_out; 2613 defobj = req.defobj_out; 2614 } 2615 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 2616 handle == RTLD_SELF) { /* ... caller included */ 2617 if (handle == RTLD_NEXT) 2618 obj = obj->next; 2619 for (; obj != NULL; obj = obj->next) { 2620 res = symlook_obj(&req, obj); 2621 if (res == 0) { 2622 if (def == NULL || 2623 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 2624 def = req.sym_out; 2625 defobj = req.defobj_out; 2626 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 2627 break; 2628 } 2629 } 2630 } 2631 /* 2632 * Search the dynamic linker itself, and possibly resolve the 2633 * symbol from there. This is how the application links to 2634 * dynamic linker services such as dlopen. 2635 */ 2636 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2637 res = symlook_obj(&req, &obj_rtld); 2638 if (res == 0) { 2639 def = req.sym_out; 2640 defobj = req.defobj_out; 2641 } 2642 } 2643 } else { 2644 assert(handle == RTLD_DEFAULT); 2645 res = symlook_default(&req, obj); 2646 if (res == 0) { 2647 defobj = req.defobj_out; 2648 def = req.sym_out; 2649 } 2650 } 2651 } else { 2652 if ((obj = dlcheck(handle)) == NULL) { 2653 lock_release(rtld_bind_lock, &lockstate); 2654 return NULL; 2655 } 2656 2657 donelist_init(&donelist); 2658 if (obj->mainprog) { 2659 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 2660 res = symlook_global(&req, &donelist); 2661 if (res == 0) { 2662 def = req.sym_out; 2663 defobj = req.defobj_out; 2664 } 2665 /* 2666 * Search the dynamic linker itself, and possibly resolve the 2667 * symbol from there. This is how the application links to 2668 * dynamic linker services such as dlopen. 2669 */ 2670 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2671 res = symlook_obj(&req, &obj_rtld); 2672 if (res == 0) { 2673 def = req.sym_out; 2674 defobj = req.defobj_out; 2675 } 2676 } 2677 } 2678 else { 2679 /* Search the whole DAG rooted at the given object. */ 2680 res = symlook_list(&req, &obj->dagmembers, &donelist); 2681 if (res == 0) { 2682 def = req.sym_out; 2683 defobj = req.defobj_out; 2684 } 2685 } 2686 } 2687 2688 if (def != NULL) { 2689 lock_release(rtld_bind_lock, &lockstate); 2690 2691 /* 2692 * The value required by the caller is derived from the value 2693 * of the symbol. For the ia64 architecture, we need to 2694 * construct a function descriptor which the caller can use to 2695 * call the function with the right 'gp' value. For other 2696 * architectures and for non-functions, the value is simply 2697 * the relocated value of the symbol. 2698 */ 2699 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 2700 return (make_function_pointer(def, defobj)); 2701 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 2702 return (rtld_resolve_ifunc(defobj, def)); 2703 else 2704 return (defobj->relocbase + def->st_value); 2705 } 2706 2707 _rtld_error("Undefined symbol \"%s\"", name); 2708 lock_release(rtld_bind_lock, &lockstate); 2709 return NULL; 2710 } 2711 2712 void * 2713 dlsym(void *handle, const char *name) 2714 { 2715 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 2716 SYMLOOK_DLSYM); 2717 } 2718 2719 dlfunc_t 2720 dlfunc(void *handle, const char *name) 2721 { 2722 union { 2723 void *d; 2724 dlfunc_t f; 2725 } rv; 2726 2727 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 2728 SYMLOOK_DLSYM); 2729 return (rv.f); 2730 } 2731 2732 void * 2733 dlvsym(void *handle, const char *name, const char *version) 2734 { 2735 Ver_Entry ventry; 2736 2737 ventry.name = version; 2738 ventry.file = NULL; 2739 ventry.hash = elf_hash(version); 2740 ventry.flags= 0; 2741 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 2742 SYMLOOK_DLSYM); 2743 } 2744 2745 int 2746 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 2747 { 2748 const Obj_Entry *obj; 2749 RtldLockState lockstate; 2750 2751 rlock_acquire(rtld_bind_lock, &lockstate); 2752 obj = obj_from_addr(addr); 2753 if (obj == NULL) { 2754 _rtld_error("No shared object contains address"); 2755 lock_release(rtld_bind_lock, &lockstate); 2756 return (0); 2757 } 2758 rtld_fill_dl_phdr_info(obj, phdr_info); 2759 lock_release(rtld_bind_lock, &lockstate); 2760 return (1); 2761 } 2762 2763 int 2764 dladdr(const void *addr, Dl_info *info) 2765 { 2766 const Obj_Entry *obj; 2767 const Elf_Sym *def; 2768 void *symbol_addr; 2769 unsigned long symoffset; 2770 RtldLockState lockstate; 2771 2772 rlock_acquire(rtld_bind_lock, &lockstate); 2773 obj = obj_from_addr(addr); 2774 if (obj == NULL) { 2775 _rtld_error("No shared object contains address"); 2776 lock_release(rtld_bind_lock, &lockstate); 2777 return 0; 2778 } 2779 info->dli_fname = obj->path; 2780 info->dli_fbase = obj->mapbase; 2781 info->dli_saddr = (void *)0; 2782 info->dli_sname = NULL; 2783 2784 /* 2785 * Walk the symbol list looking for the symbol whose address is 2786 * closest to the address sent in. 2787 */ 2788 for (symoffset = 0; symoffset < obj->nchains; symoffset++) { 2789 def = obj->symtab + symoffset; 2790 2791 /* 2792 * For skip the symbol if st_shndx is either SHN_UNDEF or 2793 * SHN_COMMON. 2794 */ 2795 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 2796 continue; 2797 2798 /* 2799 * If the symbol is greater than the specified address, or if it 2800 * is further away from addr than the current nearest symbol, 2801 * then reject it. 2802 */ 2803 symbol_addr = obj->relocbase + def->st_value; 2804 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 2805 continue; 2806 2807 /* Update our idea of the nearest symbol. */ 2808 info->dli_sname = obj->strtab + def->st_name; 2809 info->dli_saddr = symbol_addr; 2810 2811 /* Exact match? */ 2812 if (info->dli_saddr == addr) 2813 break; 2814 } 2815 lock_release(rtld_bind_lock, &lockstate); 2816 return 1; 2817 } 2818 2819 int 2820 dlinfo(void *handle, int request, void *p) 2821 { 2822 const Obj_Entry *obj; 2823 RtldLockState lockstate; 2824 int error; 2825 2826 rlock_acquire(rtld_bind_lock, &lockstate); 2827 2828 if (handle == NULL || handle == RTLD_SELF) { 2829 void *retaddr; 2830 2831 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 2832 if ((obj = obj_from_addr(retaddr)) == NULL) 2833 _rtld_error("Cannot determine caller's shared object"); 2834 } else 2835 obj = dlcheck(handle); 2836 2837 if (obj == NULL) { 2838 lock_release(rtld_bind_lock, &lockstate); 2839 return (-1); 2840 } 2841 2842 error = 0; 2843 switch (request) { 2844 case RTLD_DI_LINKMAP: 2845 *((struct link_map const **)p) = &obj->linkmap; 2846 break; 2847 case RTLD_DI_ORIGIN: 2848 error = rtld_dirname(obj->path, p); 2849 break; 2850 2851 case RTLD_DI_SERINFOSIZE: 2852 case RTLD_DI_SERINFO: 2853 error = do_search_info(obj, request, (struct dl_serinfo *)p); 2854 break; 2855 2856 default: 2857 _rtld_error("Invalid request %d passed to dlinfo()", request); 2858 error = -1; 2859 } 2860 2861 lock_release(rtld_bind_lock, &lockstate); 2862 2863 return (error); 2864 } 2865 2866 static void 2867 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 2868 { 2869 2870 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 2871 phdr_info->dlpi_name = STAILQ_FIRST(&obj->names) ? 2872 STAILQ_FIRST(&obj->names)->name : obj->path; 2873 phdr_info->dlpi_phdr = obj->phdr; 2874 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 2875 phdr_info->dlpi_tls_modid = obj->tlsindex; 2876 phdr_info->dlpi_tls_data = obj->tlsinit; 2877 phdr_info->dlpi_adds = obj_loads; 2878 phdr_info->dlpi_subs = obj_loads - obj_count; 2879 } 2880 2881 int 2882 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 2883 { 2884 struct dl_phdr_info phdr_info; 2885 const Obj_Entry *obj; 2886 RtldLockState bind_lockstate, phdr_lockstate; 2887 int error; 2888 2889 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 2890 rlock_acquire(rtld_bind_lock, &bind_lockstate); 2891 2892 error = 0; 2893 2894 for (obj = obj_list; obj != NULL; obj = obj->next) { 2895 rtld_fill_dl_phdr_info(obj, &phdr_info); 2896 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0) 2897 break; 2898 2899 } 2900 lock_release(rtld_bind_lock, &bind_lockstate); 2901 lock_release(rtld_phdr_lock, &phdr_lockstate); 2902 2903 return (error); 2904 } 2905 2906 struct fill_search_info_args { 2907 int request; 2908 unsigned int flags; 2909 Dl_serinfo *serinfo; 2910 Dl_serpath *serpath; 2911 char *strspace; 2912 }; 2913 2914 static void * 2915 fill_search_info(const char *dir, size_t dirlen, void *param) 2916 { 2917 struct fill_search_info_args *arg; 2918 2919 arg = param; 2920 2921 if (arg->request == RTLD_DI_SERINFOSIZE) { 2922 arg->serinfo->dls_cnt ++; 2923 arg->serinfo->dls_size += sizeof(Dl_serpath) + dirlen + 1; 2924 } else { 2925 struct dl_serpath *s_entry; 2926 2927 s_entry = arg->serpath; 2928 s_entry->dls_name = arg->strspace; 2929 s_entry->dls_flags = arg->flags; 2930 2931 strncpy(arg->strspace, dir, dirlen); 2932 arg->strspace[dirlen] = '\0'; 2933 2934 arg->strspace += dirlen + 1; 2935 arg->serpath++; 2936 } 2937 2938 return (NULL); 2939 } 2940 2941 static int 2942 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 2943 { 2944 struct dl_serinfo _info; 2945 struct fill_search_info_args args; 2946 2947 args.request = RTLD_DI_SERINFOSIZE; 2948 args.serinfo = &_info; 2949 2950 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2951 _info.dls_cnt = 0; 2952 2953 path_enumerate(ld_library_path, fill_search_info, &args); 2954 path_enumerate(obj->rpath, fill_search_info, &args); 2955 path_enumerate(gethints(), fill_search_info, &args); 2956 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 2957 2958 2959 if (request == RTLD_DI_SERINFOSIZE) { 2960 info->dls_size = _info.dls_size; 2961 info->dls_cnt = _info.dls_cnt; 2962 return (0); 2963 } 2964 2965 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 2966 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 2967 return (-1); 2968 } 2969 2970 args.request = RTLD_DI_SERINFO; 2971 args.serinfo = info; 2972 args.serpath = &info->dls_serpath[0]; 2973 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 2974 2975 args.flags = LA_SER_LIBPATH; 2976 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 2977 return (-1); 2978 2979 args.flags = LA_SER_RUNPATH; 2980 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 2981 return (-1); 2982 2983 args.flags = LA_SER_CONFIG; 2984 if (path_enumerate(gethints(), fill_search_info, &args) != NULL) 2985 return (-1); 2986 2987 args.flags = LA_SER_DEFAULT; 2988 if (path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 2989 return (-1); 2990 return (0); 2991 } 2992 2993 static int 2994 rtld_dirname(const char *path, char *bname) 2995 { 2996 const char *endp; 2997 2998 /* Empty or NULL string gets treated as "." */ 2999 if (path == NULL || *path == '\0') { 3000 bname[0] = '.'; 3001 bname[1] = '\0'; 3002 return (0); 3003 } 3004 3005 /* Strip trailing slashes */ 3006 endp = path + strlen(path) - 1; 3007 while (endp > path && *endp == '/') 3008 endp--; 3009 3010 /* Find the start of the dir */ 3011 while (endp > path && *endp != '/') 3012 endp--; 3013 3014 /* Either the dir is "/" or there are no slashes */ 3015 if (endp == path) { 3016 bname[0] = *endp == '/' ? '/' : '.'; 3017 bname[1] = '\0'; 3018 return (0); 3019 } else { 3020 do { 3021 endp--; 3022 } while (endp > path && *endp == '/'); 3023 } 3024 3025 if (endp - path + 2 > PATH_MAX) 3026 { 3027 _rtld_error("Filename is too long: %s", path); 3028 return(-1); 3029 } 3030 3031 strncpy(bname, path, endp - path + 1); 3032 bname[endp - path + 1] = '\0'; 3033 return (0); 3034 } 3035 3036 static int 3037 rtld_dirname_abs(const char *path, char *base) 3038 { 3039 char base_rel[PATH_MAX]; 3040 3041 if (rtld_dirname(path, base) == -1) 3042 return (-1); 3043 if (base[0] == '/') 3044 return (0); 3045 if (getcwd(base_rel, sizeof(base_rel)) == NULL || 3046 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) || 3047 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel)) 3048 return (-1); 3049 strcpy(base, base_rel); 3050 return (0); 3051 } 3052 3053 static void 3054 linkmap_add(Obj_Entry *obj) 3055 { 3056 struct link_map *l = &obj->linkmap; 3057 struct link_map *prev; 3058 3059 obj->linkmap.l_name = obj->path; 3060 obj->linkmap.l_addr = obj->mapbase; 3061 obj->linkmap.l_ld = obj->dynamic; 3062 #ifdef __mips__ 3063 /* GDB needs load offset on MIPS to use the symbols */ 3064 obj->linkmap.l_offs = obj->relocbase; 3065 #endif 3066 3067 if (r_debug.r_map == NULL) { 3068 r_debug.r_map = l; 3069 return; 3070 } 3071 3072 /* 3073 * Scan to the end of the list, but not past the entry for the 3074 * dynamic linker, which we want to keep at the very end. 3075 */ 3076 for (prev = r_debug.r_map; 3077 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3078 prev = prev->l_next) 3079 ; 3080 3081 /* Link in the new entry. */ 3082 l->l_prev = prev; 3083 l->l_next = prev->l_next; 3084 if (l->l_next != NULL) 3085 l->l_next->l_prev = l; 3086 prev->l_next = l; 3087 } 3088 3089 static void 3090 linkmap_delete(Obj_Entry *obj) 3091 { 3092 struct link_map *l = &obj->linkmap; 3093 3094 if (l->l_prev == NULL) { 3095 if ((r_debug.r_map = l->l_next) != NULL) 3096 l->l_next->l_prev = NULL; 3097 return; 3098 } 3099 3100 if ((l->l_prev->l_next = l->l_next) != NULL) 3101 l->l_next->l_prev = l->l_prev; 3102 } 3103 3104 /* 3105 * Function for the debugger to set a breakpoint on to gain control. 3106 * 3107 * The two parameters allow the debugger to easily find and determine 3108 * what the runtime loader is doing and to whom it is doing it. 3109 * 3110 * When the loadhook trap is hit (r_debug_state, set at program 3111 * initialization), the arguments can be found on the stack: 3112 * 3113 * +8 struct link_map *m 3114 * +4 struct r_debug *rd 3115 * +0 RetAddr 3116 */ 3117 void 3118 r_debug_state(struct r_debug* rd, struct link_map *m) 3119 { 3120 /* 3121 * The following is a hack to force the compiler to emit calls to 3122 * this function, even when optimizing. If the function is empty, 3123 * the compiler is not obliged to emit any code for calls to it, 3124 * even when marked __noinline. However, gdb depends on those 3125 * calls being made. 3126 */ 3127 __asm __volatile("" : : : "memory"); 3128 } 3129 3130 /* 3131 * Get address of the pointer variable in the main program. 3132 * Prefer non-weak symbol over the weak one. 3133 */ 3134 static const void ** 3135 get_program_var_addr(const char *name, RtldLockState *lockstate) 3136 { 3137 SymLook req; 3138 DoneList donelist; 3139 3140 symlook_init(&req, name); 3141 req.lockstate = lockstate; 3142 donelist_init(&donelist); 3143 if (symlook_global(&req, &donelist) != 0) 3144 return (NULL); 3145 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 3146 return ((const void **)make_function_pointer(req.sym_out, 3147 req.defobj_out)); 3148 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 3149 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 3150 else 3151 return ((const void **)(req.defobj_out->relocbase + 3152 req.sym_out->st_value)); 3153 } 3154 3155 /* 3156 * Set a pointer variable in the main program to the given value. This 3157 * is used to set key variables such as "environ" before any of the 3158 * init functions are called. 3159 */ 3160 static void 3161 set_program_var(const char *name, const void *value) 3162 { 3163 const void **addr; 3164 3165 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 3166 dbg("\"%s\": *%p <-- %p", name, addr, value); 3167 *addr = value; 3168 } 3169 } 3170 3171 /* 3172 * Search the global objects, including dependencies and main object, 3173 * for the given symbol. 3174 */ 3175 static int 3176 symlook_global(SymLook *req, DoneList *donelist) 3177 { 3178 SymLook req1; 3179 const Objlist_Entry *elm; 3180 int res; 3181 3182 symlook_init_from_req(&req1, req); 3183 3184 /* Search all objects loaded at program start up. */ 3185 if (req->defobj_out == NULL || 3186 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3187 res = symlook_list(&req1, &list_main, donelist); 3188 if (res == 0 && (req->defobj_out == NULL || 3189 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3190 req->sym_out = req1.sym_out; 3191 req->defobj_out = req1.defobj_out; 3192 assert(req->defobj_out != NULL); 3193 } 3194 } 3195 3196 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 3197 STAILQ_FOREACH(elm, &list_global, link) { 3198 if (req->defobj_out != NULL && 3199 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3200 break; 3201 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 3202 if (res == 0 && (req->defobj_out == NULL || 3203 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3204 req->sym_out = req1.sym_out; 3205 req->defobj_out = req1.defobj_out; 3206 assert(req->defobj_out != NULL); 3207 } 3208 } 3209 3210 return (req->sym_out != NULL ? 0 : ESRCH); 3211 } 3212 3213 /* 3214 * Given a symbol name in a referencing object, find the corresponding 3215 * definition of the symbol. Returns a pointer to the symbol, or NULL if 3216 * no definition was found. Returns a pointer to the Obj_Entry of the 3217 * defining object via the reference parameter DEFOBJ_OUT. 3218 */ 3219 static int 3220 symlook_default(SymLook *req, const Obj_Entry *refobj) 3221 { 3222 DoneList donelist; 3223 const Objlist_Entry *elm; 3224 SymLook req1; 3225 int res; 3226 3227 donelist_init(&donelist); 3228 symlook_init_from_req(&req1, req); 3229 3230 /* Look first in the referencing object if linked symbolically. */ 3231 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 3232 res = symlook_obj(&req1, refobj); 3233 if (res == 0) { 3234 req->sym_out = req1.sym_out; 3235 req->defobj_out = req1.defobj_out; 3236 assert(req->defobj_out != NULL); 3237 } 3238 } 3239 3240 symlook_global(req, &donelist); 3241 3242 /* Search all dlopened DAGs containing the referencing object. */ 3243 STAILQ_FOREACH(elm, &refobj->dldags, link) { 3244 if (req->sym_out != NULL && 3245 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3246 break; 3247 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 3248 if (res == 0 && (req->sym_out == NULL || 3249 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3250 req->sym_out = req1.sym_out; 3251 req->defobj_out = req1.defobj_out; 3252 assert(req->defobj_out != NULL); 3253 } 3254 } 3255 3256 /* 3257 * Search the dynamic linker itself, and possibly resolve the 3258 * symbol from there. This is how the application links to 3259 * dynamic linker services such as dlopen. 3260 */ 3261 if (req->sym_out == NULL || 3262 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3263 res = symlook_obj(&req1, &obj_rtld); 3264 if (res == 0) { 3265 req->sym_out = req1.sym_out; 3266 req->defobj_out = req1.defobj_out; 3267 assert(req->defobj_out != NULL); 3268 } 3269 } 3270 3271 return (req->sym_out != NULL ? 0 : ESRCH); 3272 } 3273 3274 static int 3275 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 3276 { 3277 const Elf_Sym *def; 3278 const Obj_Entry *defobj; 3279 const Objlist_Entry *elm; 3280 SymLook req1; 3281 int res; 3282 3283 def = NULL; 3284 defobj = NULL; 3285 STAILQ_FOREACH(elm, objlist, link) { 3286 if (donelist_check(dlp, elm->obj)) 3287 continue; 3288 symlook_init_from_req(&req1, req); 3289 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 3290 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3291 def = req1.sym_out; 3292 defobj = req1.defobj_out; 3293 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3294 break; 3295 } 3296 } 3297 } 3298 if (def != NULL) { 3299 req->sym_out = def; 3300 req->defobj_out = defobj; 3301 return (0); 3302 } 3303 return (ESRCH); 3304 } 3305 3306 /* 3307 * Search the chain of DAGS cointed to by the given Needed_Entry 3308 * for a symbol of the given name. Each DAG is scanned completely 3309 * before advancing to the next one. Returns a pointer to the symbol, 3310 * or NULL if no definition was found. 3311 */ 3312 static int 3313 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 3314 { 3315 const Elf_Sym *def; 3316 const Needed_Entry *n; 3317 const Obj_Entry *defobj; 3318 SymLook req1; 3319 int res; 3320 3321 def = NULL; 3322 defobj = NULL; 3323 symlook_init_from_req(&req1, req); 3324 for (n = needed; n != NULL; n = n->next) { 3325 if (n->obj == NULL || 3326 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 3327 continue; 3328 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3329 def = req1.sym_out; 3330 defobj = req1.defobj_out; 3331 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3332 break; 3333 } 3334 } 3335 if (def != NULL) { 3336 req->sym_out = def; 3337 req->defobj_out = defobj; 3338 return (0); 3339 } 3340 return (ESRCH); 3341 } 3342 3343 /* 3344 * Search the symbol table of a single shared object for a symbol of 3345 * the given name and version, if requested. Returns a pointer to the 3346 * symbol, or NULL if no definition was found. If the object is 3347 * filter, return filtered symbol from filtee. 3348 * 3349 * The symbol's hash value is passed in for efficiency reasons; that 3350 * eliminates many recomputations of the hash value. 3351 */ 3352 int 3353 symlook_obj(SymLook *req, const Obj_Entry *obj) 3354 { 3355 DoneList donelist; 3356 SymLook req1; 3357 int res, mres; 3358 3359 mres = symlook_obj1(req, obj); 3360 if (mres == 0) { 3361 if (obj->needed_filtees != NULL) { 3362 load_filtees(__DECONST(Obj_Entry *, obj), 0, req->lockstate); 3363 donelist_init(&donelist); 3364 symlook_init_from_req(&req1, req); 3365 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 3366 if (res == 0) { 3367 req->sym_out = req1.sym_out; 3368 req->defobj_out = req1.defobj_out; 3369 } 3370 return (res); 3371 } 3372 if (obj->needed_aux_filtees != NULL) { 3373 load_filtees(__DECONST(Obj_Entry *, obj), 0, req->lockstate); 3374 donelist_init(&donelist); 3375 symlook_init_from_req(&req1, req); 3376 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 3377 if (res == 0) { 3378 req->sym_out = req1.sym_out; 3379 req->defobj_out = req1.defobj_out; 3380 return (res); 3381 } 3382 } 3383 } 3384 return (mres); 3385 } 3386 3387 static int 3388 symlook_obj1(SymLook *req, const Obj_Entry *obj) 3389 { 3390 unsigned long symnum; 3391 const Elf_Sym *vsymp; 3392 Elf_Versym verndx; 3393 int vcount; 3394 3395 if (obj->buckets == NULL) 3396 return (ESRCH); 3397 3398 vsymp = NULL; 3399 vcount = 0; 3400 symnum = obj->buckets[req->hash % obj->nbuckets]; 3401 3402 for (; symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 3403 const Elf_Sym *symp; 3404 const char *strp; 3405 3406 if (symnum >= obj->nchains) 3407 return (ESRCH); /* Bad object */ 3408 3409 symp = obj->symtab + symnum; 3410 strp = obj->strtab + symp->st_name; 3411 3412 switch (ELF_ST_TYPE(symp->st_info)) { 3413 case STT_FUNC: 3414 case STT_NOTYPE: 3415 case STT_OBJECT: 3416 case STT_GNU_IFUNC: 3417 if (symp->st_value == 0) 3418 continue; 3419 /* fallthrough */ 3420 case STT_TLS: 3421 if (symp->st_shndx != SHN_UNDEF) 3422 break; 3423 #ifndef __mips__ 3424 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 3425 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 3426 break; 3427 /* fallthrough */ 3428 #endif 3429 default: 3430 continue; 3431 } 3432 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 3433 continue; 3434 3435 if (req->ventry == NULL) { 3436 if (obj->versyms != NULL) { 3437 verndx = VER_NDX(obj->versyms[symnum]); 3438 if (verndx > obj->vernum) { 3439 _rtld_error("%s: symbol %s references wrong version %d", 3440 obj->path, obj->strtab + symnum, verndx); 3441 continue; 3442 } 3443 /* 3444 * If we are not called from dlsym (i.e. this is a normal 3445 * relocation from unversioned binary), accept the symbol 3446 * immediately if it happens to have first version after 3447 * this shared object became versioned. Otherwise, if 3448 * symbol is versioned and not hidden, remember it. If it 3449 * is the only symbol with this name exported by the 3450 * shared object, it will be returned as a match at the 3451 * end of the function. If symbol is global (verndx < 2) 3452 * accept it unconditionally. 3453 */ 3454 if ((req->flags & SYMLOOK_DLSYM) == 0 && 3455 verndx == VER_NDX_GIVEN) { 3456 req->sym_out = symp; 3457 req->defobj_out = obj; 3458 return (0); 3459 } 3460 else if (verndx >= VER_NDX_GIVEN) { 3461 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) == 0) { 3462 if (vsymp == NULL) 3463 vsymp = symp; 3464 vcount ++; 3465 } 3466 continue; 3467 } 3468 } 3469 req->sym_out = symp; 3470 req->defobj_out = obj; 3471 return (0); 3472 } else { 3473 if (obj->versyms == NULL) { 3474 if (object_match_name(obj, req->ventry->name)) { 3475 _rtld_error("%s: object %s should provide version %s for " 3476 "symbol %s", obj_rtld.path, obj->path, 3477 req->ventry->name, obj->strtab + symnum); 3478 continue; 3479 } 3480 } else { 3481 verndx = VER_NDX(obj->versyms[symnum]); 3482 if (verndx > obj->vernum) { 3483 _rtld_error("%s: symbol %s references wrong version %d", 3484 obj->path, obj->strtab + symnum, verndx); 3485 continue; 3486 } 3487 if (obj->vertab[verndx].hash != req->ventry->hash || 3488 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 3489 /* 3490 * Version does not match. Look if this is a global symbol 3491 * and if it is not hidden. If global symbol (verndx < 2) 3492 * is available, use it. Do not return symbol if we are 3493 * called by dlvsym, because dlvsym looks for a specific 3494 * version and default one is not what dlvsym wants. 3495 */ 3496 if ((req->flags & SYMLOOK_DLSYM) || 3497 (obj->versyms[symnum] & VER_NDX_HIDDEN) || 3498 (verndx >= VER_NDX_GIVEN)) 3499 continue; 3500 } 3501 } 3502 req->sym_out = symp; 3503 req->defobj_out = obj; 3504 return (0); 3505 } 3506 } 3507 if (vcount == 1) { 3508 req->sym_out = vsymp; 3509 req->defobj_out = obj; 3510 return (0); 3511 } 3512 return (ESRCH); 3513 } 3514 3515 static void 3516 trace_loaded_objects(Obj_Entry *obj) 3517 { 3518 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 3519 int c; 3520 3521 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 3522 main_local = ""; 3523 3524 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL) 3525 fmt1 = "\t%o => %p (%x)\n"; 3526 3527 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL) 3528 fmt2 = "\t%o (%x)\n"; 3529 3530 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL"); 3531 3532 for (; obj; obj = obj->next) { 3533 Needed_Entry *needed; 3534 char *name, *path; 3535 bool is_lib; 3536 3537 if (list_containers && obj->needed != NULL) 3538 rtld_printf("%s:\n", obj->path); 3539 for (needed = obj->needed; needed; needed = needed->next) { 3540 if (needed->obj != NULL) { 3541 if (needed->obj->traced && !list_containers) 3542 continue; 3543 needed->obj->traced = true; 3544 path = needed->obj->path; 3545 } else 3546 path = "not found"; 3547 3548 name = (char *)obj->strtab + needed->name; 3549 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 3550 3551 fmt = is_lib ? fmt1 : fmt2; 3552 while ((c = *fmt++) != '\0') { 3553 switch (c) { 3554 default: 3555 rtld_putchar(c); 3556 continue; 3557 case '\\': 3558 switch (c = *fmt) { 3559 case '\0': 3560 continue; 3561 case 'n': 3562 rtld_putchar('\n'); 3563 break; 3564 case 't': 3565 rtld_putchar('\t'); 3566 break; 3567 } 3568 break; 3569 case '%': 3570 switch (c = *fmt) { 3571 case '\0': 3572 continue; 3573 case '%': 3574 default: 3575 rtld_putchar(c); 3576 break; 3577 case 'A': 3578 rtld_putstr(main_local); 3579 break; 3580 case 'a': 3581 rtld_putstr(obj_main->path); 3582 break; 3583 case 'o': 3584 rtld_putstr(name); 3585 break; 3586 #if 0 3587 case 'm': 3588 rtld_printf("%d", sodp->sod_major); 3589 break; 3590 case 'n': 3591 rtld_printf("%d", sodp->sod_minor); 3592 break; 3593 #endif 3594 case 'p': 3595 rtld_putstr(path); 3596 break; 3597 case 'x': 3598 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 3599 0); 3600 break; 3601 } 3602 break; 3603 } 3604 ++fmt; 3605 } 3606 } 3607 } 3608 } 3609 3610 /* 3611 * Unload a dlopened object and its dependencies from memory and from 3612 * our data structures. It is assumed that the DAG rooted in the 3613 * object has already been unreferenced, and that the object has a 3614 * reference count of 0. 3615 */ 3616 static void 3617 unload_object(Obj_Entry *root) 3618 { 3619 Obj_Entry *obj; 3620 Obj_Entry **linkp; 3621 3622 assert(root->refcount == 0); 3623 3624 /* 3625 * Pass over the DAG removing unreferenced objects from 3626 * appropriate lists. 3627 */ 3628 unlink_object(root); 3629 3630 /* Unmap all objects that are no longer referenced. */ 3631 linkp = &obj_list->next; 3632 while ((obj = *linkp) != NULL) { 3633 if (obj->refcount == 0) { 3634 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 3635 obj->path); 3636 dbg("unloading \"%s\"", obj->path); 3637 unload_filtees(root); 3638 munmap(obj->mapbase, obj->mapsize); 3639 linkmap_delete(obj); 3640 *linkp = obj->next; 3641 obj_count--; 3642 obj_free(obj); 3643 } else 3644 linkp = &obj->next; 3645 } 3646 obj_tail = linkp; 3647 } 3648 3649 static void 3650 unlink_object(Obj_Entry *root) 3651 { 3652 Objlist_Entry *elm; 3653 3654 if (root->refcount == 0) { 3655 /* Remove the object from the RTLD_GLOBAL list. */ 3656 objlist_remove(&list_global, root); 3657 3658 /* Remove the object from all objects' DAG lists. */ 3659 STAILQ_FOREACH(elm, &root->dagmembers, link) { 3660 objlist_remove(&elm->obj->dldags, root); 3661 if (elm->obj != root) 3662 unlink_object(elm->obj); 3663 } 3664 } 3665 } 3666 3667 static void 3668 ref_dag(Obj_Entry *root) 3669 { 3670 Objlist_Entry *elm; 3671 3672 assert(root->dag_inited); 3673 STAILQ_FOREACH(elm, &root->dagmembers, link) 3674 elm->obj->refcount++; 3675 } 3676 3677 static void 3678 unref_dag(Obj_Entry *root) 3679 { 3680 Objlist_Entry *elm; 3681 3682 assert(root->dag_inited); 3683 STAILQ_FOREACH(elm, &root->dagmembers, link) 3684 elm->obj->refcount--; 3685 } 3686 3687 /* 3688 * Common code for MD __tls_get_addr(). 3689 */ 3690 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 3691 static void * 3692 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 3693 { 3694 Elf_Addr *newdtv, *dtv; 3695 RtldLockState lockstate; 3696 int to_copy; 3697 3698 dtv = *dtvp; 3699 /* Check dtv generation in case new modules have arrived */ 3700 if (dtv[0] != tls_dtv_generation) { 3701 wlock_acquire(rtld_bind_lock, &lockstate); 3702 newdtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr)); 3703 to_copy = dtv[1]; 3704 if (to_copy > tls_max_index) 3705 to_copy = tls_max_index; 3706 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 3707 newdtv[0] = tls_dtv_generation; 3708 newdtv[1] = tls_max_index; 3709 free(dtv); 3710 lock_release(rtld_bind_lock, &lockstate); 3711 dtv = *dtvp = newdtv; 3712 } 3713 3714 /* Dynamically allocate module TLS if necessary */ 3715 if (dtv[index + 1] == 0) { 3716 /* Signal safe, wlock will block out signals. */ 3717 wlock_acquire(rtld_bind_lock, &lockstate); 3718 if (!dtv[index + 1]) 3719 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 3720 lock_release(rtld_bind_lock, &lockstate); 3721 } 3722 return ((void *)(dtv[index + 1] + offset)); 3723 } 3724 3725 void * 3726 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 3727 { 3728 Elf_Addr *dtv; 3729 3730 dtv = *dtvp; 3731 /* Check dtv generation in case new modules have arrived */ 3732 if (__predict_true(dtv[0] == tls_dtv_generation && 3733 dtv[index + 1] != 0)) 3734 return ((void *)(dtv[index + 1] + offset)); 3735 return (tls_get_addr_slow(dtvp, index, offset)); 3736 } 3737 3738 #if defined(__arm__) || defined(__ia64__) || defined(__mips__) || defined(__powerpc__) 3739 3740 /* 3741 * Allocate Static TLS using the Variant I method. 3742 */ 3743 void * 3744 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 3745 { 3746 Obj_Entry *obj; 3747 char *tcb; 3748 Elf_Addr **tls; 3749 Elf_Addr *dtv; 3750 Elf_Addr addr; 3751 int i; 3752 3753 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 3754 return (oldtcb); 3755 3756 assert(tcbsize >= TLS_TCB_SIZE); 3757 tcb = calloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 3758 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 3759 3760 if (oldtcb != NULL) { 3761 memcpy(tls, oldtcb, tls_static_space); 3762 free(oldtcb); 3763 3764 /* Adjust the DTV. */ 3765 dtv = tls[0]; 3766 for (i = 0; i < dtv[1]; i++) { 3767 if (dtv[i+2] >= (Elf_Addr)oldtcb && 3768 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 3769 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 3770 } 3771 } 3772 } else { 3773 dtv = calloc(tls_max_index + 2, sizeof(Elf_Addr)); 3774 tls[0] = dtv; 3775 dtv[0] = tls_dtv_generation; 3776 dtv[1] = tls_max_index; 3777 3778 for (obj = objs; obj; obj = obj->next) { 3779 if (obj->tlsoffset > 0) { 3780 addr = (Elf_Addr)tls + obj->tlsoffset; 3781 if (obj->tlsinitsize > 0) 3782 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 3783 if (obj->tlssize > obj->tlsinitsize) 3784 memset((void*) (addr + obj->tlsinitsize), 0, 3785 obj->tlssize - obj->tlsinitsize); 3786 dtv[obj->tlsindex + 1] = addr; 3787 } 3788 } 3789 } 3790 3791 return (tcb); 3792 } 3793 3794 void 3795 free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 3796 { 3797 Elf_Addr *dtv; 3798 Elf_Addr tlsstart, tlsend; 3799 int dtvsize, i; 3800 3801 assert(tcbsize >= TLS_TCB_SIZE); 3802 3803 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 3804 tlsend = tlsstart + tls_static_space; 3805 3806 dtv = *(Elf_Addr **)tlsstart; 3807 dtvsize = dtv[1]; 3808 for (i = 0; i < dtvsize; i++) { 3809 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 3810 free((void*)dtv[i+2]); 3811 } 3812 } 3813 free(dtv); 3814 free(tcb); 3815 } 3816 3817 #endif 3818 3819 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 3820 3821 /* 3822 * Allocate Static TLS using the Variant II method. 3823 */ 3824 void * 3825 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 3826 { 3827 Obj_Entry *obj; 3828 size_t size; 3829 char *tls; 3830 Elf_Addr *dtv, *olddtv; 3831 Elf_Addr segbase, oldsegbase, addr; 3832 int i; 3833 3834 size = round(tls_static_space, tcbalign); 3835 3836 assert(tcbsize >= 2*sizeof(Elf_Addr)); 3837 tls = calloc(1, size + tcbsize); 3838 dtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr)); 3839 3840 segbase = (Elf_Addr)(tls + size); 3841 ((Elf_Addr*)segbase)[0] = segbase; 3842 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 3843 3844 dtv[0] = tls_dtv_generation; 3845 dtv[1] = tls_max_index; 3846 3847 if (oldtls) { 3848 /* 3849 * Copy the static TLS block over whole. 3850 */ 3851 oldsegbase = (Elf_Addr) oldtls; 3852 memcpy((void *)(segbase - tls_static_space), 3853 (const void *)(oldsegbase - tls_static_space), 3854 tls_static_space); 3855 3856 /* 3857 * If any dynamic TLS blocks have been created tls_get_addr(), 3858 * move them over. 3859 */ 3860 olddtv = ((Elf_Addr**)oldsegbase)[1]; 3861 for (i = 0; i < olddtv[1]; i++) { 3862 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 3863 dtv[i+2] = olddtv[i+2]; 3864 olddtv[i+2] = 0; 3865 } 3866 } 3867 3868 /* 3869 * We assume that this block was the one we created with 3870 * allocate_initial_tls(). 3871 */ 3872 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 3873 } else { 3874 for (obj = objs; obj; obj = obj->next) { 3875 if (obj->tlsoffset) { 3876 addr = segbase - obj->tlsoffset; 3877 memset((void*) (addr + obj->tlsinitsize), 3878 0, obj->tlssize - obj->tlsinitsize); 3879 if (obj->tlsinit) 3880 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 3881 dtv[obj->tlsindex + 1] = addr; 3882 } 3883 } 3884 } 3885 3886 return (void*) segbase; 3887 } 3888 3889 void 3890 free_tls(void *tls, size_t tcbsize, size_t tcbalign) 3891 { 3892 size_t size; 3893 Elf_Addr* dtv; 3894 int dtvsize, i; 3895 Elf_Addr tlsstart, tlsend; 3896 3897 /* 3898 * Figure out the size of the initial TLS block so that we can 3899 * find stuff which ___tls_get_addr() allocated dynamically. 3900 */ 3901 size = round(tls_static_space, tcbalign); 3902 3903 dtv = ((Elf_Addr**)tls)[1]; 3904 dtvsize = dtv[1]; 3905 tlsend = (Elf_Addr) tls; 3906 tlsstart = tlsend - size; 3907 for (i = 0; i < dtvsize; i++) { 3908 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] > tlsend)) { 3909 free((void*) dtv[i+2]); 3910 } 3911 } 3912 3913 free((void*) tlsstart); 3914 free((void*) dtv); 3915 } 3916 3917 #endif 3918 3919 /* 3920 * Allocate TLS block for module with given index. 3921 */ 3922 void * 3923 allocate_module_tls(int index) 3924 { 3925 Obj_Entry* obj; 3926 char* p; 3927 3928 for (obj = obj_list; obj; obj = obj->next) { 3929 if (obj->tlsindex == index) 3930 break; 3931 } 3932 if (!obj) { 3933 _rtld_error("Can't find module with TLS index %d", index); 3934 die(); 3935 } 3936 3937 p = malloc(obj->tlssize); 3938 if (p == NULL) { 3939 _rtld_error("Cannot allocate TLS block for index %d", index); 3940 die(); 3941 } 3942 memcpy(p, obj->tlsinit, obj->tlsinitsize); 3943 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 3944 3945 return p; 3946 } 3947 3948 bool 3949 allocate_tls_offset(Obj_Entry *obj) 3950 { 3951 size_t off; 3952 3953 if (obj->tls_done) 3954 return true; 3955 3956 if (obj->tlssize == 0) { 3957 obj->tls_done = true; 3958 return true; 3959 } 3960 3961 if (obj->tlsindex == 1) 3962 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 3963 else 3964 off = calculate_tls_offset(tls_last_offset, tls_last_size, 3965 obj->tlssize, obj->tlsalign); 3966 3967 /* 3968 * If we have already fixed the size of the static TLS block, we 3969 * must stay within that size. When allocating the static TLS, we 3970 * leave a small amount of space spare to be used for dynamically 3971 * loading modules which use static TLS. 3972 */ 3973 if (tls_static_space) { 3974 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 3975 return false; 3976 } 3977 3978 tls_last_offset = obj->tlsoffset = off; 3979 tls_last_size = obj->tlssize; 3980 obj->tls_done = true; 3981 3982 return true; 3983 } 3984 3985 void 3986 free_tls_offset(Obj_Entry *obj) 3987 { 3988 3989 /* 3990 * If we were the last thing to allocate out of the static TLS 3991 * block, we give our space back to the 'allocator'. This is a 3992 * simplistic workaround to allow libGL.so.1 to be loaded and 3993 * unloaded multiple times. 3994 */ 3995 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 3996 == calculate_tls_end(tls_last_offset, tls_last_size)) { 3997 tls_last_offset -= obj->tlssize; 3998 tls_last_size = 0; 3999 } 4000 } 4001 4002 void * 4003 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 4004 { 4005 void *ret; 4006 RtldLockState lockstate; 4007 4008 wlock_acquire(rtld_bind_lock, &lockstate); 4009 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign); 4010 lock_release(rtld_bind_lock, &lockstate); 4011 return (ret); 4012 } 4013 4014 void 4015 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4016 { 4017 RtldLockState lockstate; 4018 4019 wlock_acquire(rtld_bind_lock, &lockstate); 4020 free_tls(tcb, tcbsize, tcbalign); 4021 lock_release(rtld_bind_lock, &lockstate); 4022 } 4023 4024 static void 4025 object_add_name(Obj_Entry *obj, const char *name) 4026 { 4027 Name_Entry *entry; 4028 size_t len; 4029 4030 len = strlen(name); 4031 entry = malloc(sizeof(Name_Entry) + len); 4032 4033 if (entry != NULL) { 4034 strcpy(entry->name, name); 4035 STAILQ_INSERT_TAIL(&obj->names, entry, link); 4036 } 4037 } 4038 4039 static int 4040 object_match_name(const Obj_Entry *obj, const char *name) 4041 { 4042 Name_Entry *entry; 4043 4044 STAILQ_FOREACH(entry, &obj->names, link) { 4045 if (strcmp(name, entry->name) == 0) 4046 return (1); 4047 } 4048 return (0); 4049 } 4050 4051 static Obj_Entry * 4052 locate_dependency(const Obj_Entry *obj, const char *name) 4053 { 4054 const Objlist_Entry *entry; 4055 const Needed_Entry *needed; 4056 4057 STAILQ_FOREACH(entry, &list_main, link) { 4058 if (object_match_name(entry->obj, name)) 4059 return entry->obj; 4060 } 4061 4062 for (needed = obj->needed; needed != NULL; needed = needed->next) { 4063 if (strcmp(obj->strtab + needed->name, name) == 0 || 4064 (needed->obj != NULL && object_match_name(needed->obj, name))) { 4065 /* 4066 * If there is DT_NEEDED for the name we are looking for, 4067 * we are all set. Note that object might not be found if 4068 * dependency was not loaded yet, so the function can 4069 * return NULL here. This is expected and handled 4070 * properly by the caller. 4071 */ 4072 return (needed->obj); 4073 } 4074 } 4075 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 4076 obj->path, name); 4077 die(); 4078 } 4079 4080 static int 4081 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 4082 const Elf_Vernaux *vna) 4083 { 4084 const Elf_Verdef *vd; 4085 const char *vername; 4086 4087 vername = refobj->strtab + vna->vna_name; 4088 vd = depobj->verdef; 4089 if (vd == NULL) { 4090 _rtld_error("%s: version %s required by %s not defined", 4091 depobj->path, vername, refobj->path); 4092 return (-1); 4093 } 4094 for (;;) { 4095 if (vd->vd_version != VER_DEF_CURRENT) { 4096 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4097 depobj->path, vd->vd_version); 4098 return (-1); 4099 } 4100 if (vna->vna_hash == vd->vd_hash) { 4101 const Elf_Verdaux *aux = (const Elf_Verdaux *) 4102 ((char *)vd + vd->vd_aux); 4103 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 4104 return (0); 4105 } 4106 if (vd->vd_next == 0) 4107 break; 4108 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4109 } 4110 if (vna->vna_flags & VER_FLG_WEAK) 4111 return (0); 4112 _rtld_error("%s: version %s required by %s not found", 4113 depobj->path, vername, refobj->path); 4114 return (-1); 4115 } 4116 4117 static int 4118 rtld_verify_object_versions(Obj_Entry *obj) 4119 { 4120 const Elf_Verneed *vn; 4121 const Elf_Verdef *vd; 4122 const Elf_Verdaux *vda; 4123 const Elf_Vernaux *vna; 4124 const Obj_Entry *depobj; 4125 int maxvernum, vernum; 4126 4127 maxvernum = 0; 4128 /* 4129 * Walk over defined and required version records and figure out 4130 * max index used by any of them. Do very basic sanity checking 4131 * while there. 4132 */ 4133 vn = obj->verneed; 4134 while (vn != NULL) { 4135 if (vn->vn_version != VER_NEED_CURRENT) { 4136 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 4137 obj->path, vn->vn_version); 4138 return (-1); 4139 } 4140 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4141 for (;;) { 4142 vernum = VER_NEED_IDX(vna->vna_other); 4143 if (vernum > maxvernum) 4144 maxvernum = vernum; 4145 if (vna->vna_next == 0) 4146 break; 4147 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4148 } 4149 if (vn->vn_next == 0) 4150 break; 4151 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4152 } 4153 4154 vd = obj->verdef; 4155 while (vd != NULL) { 4156 if (vd->vd_version != VER_DEF_CURRENT) { 4157 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4158 obj->path, vd->vd_version); 4159 return (-1); 4160 } 4161 vernum = VER_DEF_IDX(vd->vd_ndx); 4162 if (vernum > maxvernum) 4163 maxvernum = vernum; 4164 if (vd->vd_next == 0) 4165 break; 4166 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4167 } 4168 4169 if (maxvernum == 0) 4170 return (0); 4171 4172 /* 4173 * Store version information in array indexable by version index. 4174 * Verify that object version requirements are satisfied along the 4175 * way. 4176 */ 4177 obj->vernum = maxvernum + 1; 4178 obj->vertab = calloc(obj->vernum, sizeof(Ver_Entry)); 4179 4180 vd = obj->verdef; 4181 while (vd != NULL) { 4182 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 4183 vernum = VER_DEF_IDX(vd->vd_ndx); 4184 assert(vernum <= maxvernum); 4185 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 4186 obj->vertab[vernum].hash = vd->vd_hash; 4187 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 4188 obj->vertab[vernum].file = NULL; 4189 obj->vertab[vernum].flags = 0; 4190 } 4191 if (vd->vd_next == 0) 4192 break; 4193 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4194 } 4195 4196 vn = obj->verneed; 4197 while (vn != NULL) { 4198 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 4199 if (depobj == NULL) 4200 return (-1); 4201 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4202 for (;;) { 4203 if (check_object_provided_version(obj, depobj, vna)) 4204 return (-1); 4205 vernum = VER_NEED_IDX(vna->vna_other); 4206 assert(vernum <= maxvernum); 4207 obj->vertab[vernum].hash = vna->vna_hash; 4208 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 4209 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 4210 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 4211 VER_INFO_HIDDEN : 0; 4212 if (vna->vna_next == 0) 4213 break; 4214 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4215 } 4216 if (vn->vn_next == 0) 4217 break; 4218 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4219 } 4220 return 0; 4221 } 4222 4223 static int 4224 rtld_verify_versions(const Objlist *objlist) 4225 { 4226 Objlist_Entry *entry; 4227 int rc; 4228 4229 rc = 0; 4230 STAILQ_FOREACH(entry, objlist, link) { 4231 /* 4232 * Skip dummy objects or objects that have their version requirements 4233 * already checked. 4234 */ 4235 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 4236 continue; 4237 if (rtld_verify_object_versions(entry->obj) == -1) { 4238 rc = -1; 4239 if (ld_tracing == NULL) 4240 break; 4241 } 4242 } 4243 if (rc == 0 || ld_tracing != NULL) 4244 rc = rtld_verify_object_versions(&obj_rtld); 4245 return rc; 4246 } 4247 4248 const Ver_Entry * 4249 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 4250 { 4251 Elf_Versym vernum; 4252 4253 if (obj->vertab) { 4254 vernum = VER_NDX(obj->versyms[symnum]); 4255 if (vernum >= obj->vernum) { 4256 _rtld_error("%s: symbol %s has wrong verneed value %d", 4257 obj->path, obj->strtab + symnum, vernum); 4258 } else if (obj->vertab[vernum].hash != 0) { 4259 return &obj->vertab[vernum]; 4260 } 4261 } 4262 return NULL; 4263 } 4264 4265 int 4266 _rtld_get_stack_prot(void) 4267 { 4268 4269 return (stack_prot); 4270 } 4271 4272 static void 4273 map_stacks_exec(RtldLockState *lockstate) 4274 { 4275 void (*thr_map_stacks_exec)(void); 4276 4277 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 4278 return; 4279 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 4280 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 4281 if (thr_map_stacks_exec != NULL) { 4282 stack_prot |= PROT_EXEC; 4283 thr_map_stacks_exec(); 4284 } 4285 } 4286 4287 void 4288 symlook_init(SymLook *dst, const char *name) 4289 { 4290 4291 bzero(dst, sizeof(*dst)); 4292 dst->name = name; 4293 dst->hash = elf_hash(name); 4294 } 4295 4296 static void 4297 symlook_init_from_req(SymLook *dst, const SymLook *src) 4298 { 4299 4300 dst->name = src->name; 4301 dst->hash = src->hash; 4302 dst->ventry = src->ventry; 4303 dst->flags = src->flags; 4304 dst->defobj_out = NULL; 4305 dst->sym_out = NULL; 4306 dst->lockstate = src->lockstate; 4307 } 4308 4309 /* 4310 * Overrides for libc_pic-provided functions. 4311 */ 4312 4313 int 4314 __getosreldate(void) 4315 { 4316 size_t len; 4317 int oid[2]; 4318 int error, osrel; 4319 4320 if (osreldate != 0) 4321 return (osreldate); 4322 4323 oid[0] = CTL_KERN; 4324 oid[1] = KERN_OSRELDATE; 4325 osrel = 0; 4326 len = sizeof(osrel); 4327 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 4328 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 4329 osreldate = osrel; 4330 return (osreldate); 4331 } 4332 4333 /* 4334 * No unresolved symbols for rtld. 4335 */ 4336 void 4337 __pthread_cxa_finalize(struct dl_phdr_info *a) 4338 { 4339 } 4340 4341 void 4342 __stack_chk_fail(void) 4343 { 4344 4345 _rtld_error("stack overflow detected; terminated"); 4346 die(); 4347 } 4348 4349 void 4350 __chk_fail(void) 4351 { 4352 4353 _rtld_error("buffer overflow detected; terminated"); 4354 die(); 4355 } 4356