1 /*- 2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra. 3 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>. 4 * Copyright 2009-2012 Konstantin Belousov <kib@FreeBSD.ORG>. 5 * Copyright 2012 John Marino <draco@marino.st>. 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 * 28 * $FreeBSD$ 29 */ 30 31 /* 32 * Dynamic linker for ELF. 33 * 34 * John Polstra <jdp@polstra.com>. 35 */ 36 37 #ifndef __GNUC__ 38 #error "GCC is needed to compile this file" 39 #endif 40 41 #include <sys/param.h> 42 #include <sys/mount.h> 43 #include <sys/mman.h> 44 #include <sys/stat.h> 45 #include <sys/sysctl.h> 46 #include <sys/uio.h> 47 #include <sys/utsname.h> 48 #include <sys/ktrace.h> 49 50 #include <dlfcn.h> 51 #include <err.h> 52 #include <errno.h> 53 #include <fcntl.h> 54 #include <stdarg.h> 55 #include <stdio.h> 56 #include <stdlib.h> 57 #include <string.h> 58 #include <unistd.h> 59 60 #include "debug.h" 61 #include "rtld.h" 62 #include "libmap.h" 63 #include "rtld_tls.h" 64 #include "rtld_printf.h" 65 #include "notes.h" 66 67 #ifndef COMPAT_32BIT 68 #define PATH_RTLD "/libexec/ld-elf.so.1" 69 #else 70 #define PATH_RTLD "/libexec/ld-elf32.so.1" 71 #endif 72 73 /* Types. */ 74 typedef void (*func_ptr_type)(); 75 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 76 77 /* 78 * Function declarations. 79 */ 80 static const char *basename(const char *); 81 static void die(void) __dead2; 82 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 83 const Elf_Dyn **, const Elf_Dyn **); 84 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *, 85 const Elf_Dyn *); 86 static void digest_dynamic(Obj_Entry *, int); 87 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 88 static Obj_Entry *dlcheck(void *); 89 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, 90 int lo_flags, int mode, RtldLockState *lockstate); 91 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 92 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 93 static bool donelist_check(DoneList *, const Obj_Entry *); 94 static void errmsg_restore(char *); 95 static char *errmsg_save(void); 96 static void *fill_search_info(const char *, size_t, void *); 97 static char *find_library(const char *, const Obj_Entry *, int *); 98 static const char *gethints(bool); 99 static void init_dag(Obj_Entry *); 100 static void init_pagesizes(Elf_Auxinfo **aux_info); 101 static void init_rtld(caddr_t, Elf_Auxinfo **); 102 static void initlist_add_neededs(Needed_Entry *, Objlist *); 103 static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *); 104 static void linkmap_add(Obj_Entry *); 105 static void linkmap_delete(Obj_Entry *); 106 static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 107 static void unload_filtees(Obj_Entry *); 108 static int load_needed_objects(Obj_Entry *, int); 109 static int load_preload_objects(void); 110 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 111 static void map_stacks_exec(RtldLockState *); 112 static Obj_Entry *obj_from_addr(const void *); 113 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 114 static void objlist_call_init(Objlist *, RtldLockState *); 115 static void objlist_clear(Objlist *); 116 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 117 static void objlist_init(Objlist *); 118 static void objlist_push_head(Objlist *, Obj_Entry *); 119 static void objlist_push_tail(Objlist *, Obj_Entry *); 120 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 121 static void objlist_remove(Objlist *, Obj_Entry *); 122 static int parse_libdir(const char *); 123 static void *path_enumerate(const char *, path_enum_proc, void *); 124 static int relocate_object_dag(Obj_Entry *root, bool bind_now, 125 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 126 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 127 int flags, RtldLockState *lockstate); 128 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 129 RtldLockState *); 130 static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now, 131 int flags, RtldLockState *lockstate); 132 static int rtld_dirname(const char *, char *); 133 static int rtld_dirname_abs(const char *, char *); 134 static void *rtld_dlopen(const char *name, int fd, int mode); 135 static void rtld_exit(void); 136 static char *search_library_path(const char *, const char *); 137 static char *search_library_pathfds(const char *, const char *, int *); 138 static const void **get_program_var_addr(const char *, RtldLockState *); 139 static void set_program_var(const char *, const void *); 140 static int symlook_default(SymLook *, const Obj_Entry *refobj); 141 static int symlook_global(SymLook *, DoneList *); 142 static void symlook_init_from_req(SymLook *, const SymLook *); 143 static int symlook_list(SymLook *, const Objlist *, DoneList *); 144 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 145 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 146 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 147 static void trace_loaded_objects(Obj_Entry *); 148 static void unlink_object(Obj_Entry *); 149 static void unload_object(Obj_Entry *); 150 static void unref_dag(Obj_Entry *); 151 static void ref_dag(Obj_Entry *); 152 static char *origin_subst_one(char *, const char *, const char *, bool); 153 static char *origin_subst(char *, const char *); 154 static void preinit_main(void); 155 static int rtld_verify_versions(const Objlist *); 156 static int rtld_verify_object_versions(Obj_Entry *); 157 static void object_add_name(Obj_Entry *, const char *); 158 static int object_match_name(const Obj_Entry *, const char *); 159 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 160 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 161 struct dl_phdr_info *phdr_info); 162 static uint32_t gnu_hash(const char *); 163 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 164 const unsigned long); 165 166 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported; 167 void _r_debug_postinit(struct link_map *) __noinline __exported; 168 169 int __sys_openat(int, const char *, int, ...); 170 171 /* 172 * Data declarations. 173 */ 174 static char *error_message; /* Message for dlerror(), or NULL */ 175 struct r_debug r_debug __exported; /* for GDB; */ 176 static bool libmap_disable; /* Disable libmap */ 177 static bool ld_loadfltr; /* Immediate filters processing */ 178 static char *libmap_override; /* Maps to use in addition to libmap.conf */ 179 static bool trust; /* False for setuid and setgid programs */ 180 static bool dangerous_ld_env; /* True if environment variables have been 181 used to affect the libraries loaded */ 182 static char *ld_bind_now; /* Environment variable for immediate binding */ 183 static char *ld_debug; /* Environment variable for debugging */ 184 static char *ld_library_path; /* Environment variable for search path */ 185 static char *ld_library_dirs; /* Environment variable for library descriptors */ 186 static char *ld_preload; /* Environment variable for libraries to 187 load first */ 188 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 189 static char *ld_tracing; /* Called from ldd to print libs */ 190 static char *ld_utrace; /* Use utrace() to log events. */ 191 static Obj_Entry *obj_list; /* Head of linked list of shared objects */ 192 static Obj_Entry **obj_tail; /* Link field of last object in list */ 193 static Obj_Entry *obj_main; /* The main program shared object */ 194 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 195 static unsigned int obj_count; /* Number of objects in obj_list */ 196 static unsigned int obj_loads; /* Number of objects in obj_list */ 197 198 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 199 STAILQ_HEAD_INITIALIZER(list_global); 200 static Objlist list_main = /* Objects loaded at program startup */ 201 STAILQ_HEAD_INITIALIZER(list_main); 202 static Objlist list_fini = /* Objects needing fini() calls */ 203 STAILQ_HEAD_INITIALIZER(list_fini); 204 205 Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 206 207 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 208 209 extern Elf_Dyn _DYNAMIC; 210 #pragma weak _DYNAMIC 211 #ifndef RTLD_IS_DYNAMIC 212 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL) 213 #endif 214 215 int dlclose(void *) __exported; 216 char *dlerror(void) __exported; 217 void *dlopen(const char *, int) __exported; 218 void *fdlopen(int, int) __exported; 219 void *dlsym(void *, const char *) __exported; 220 dlfunc_t dlfunc(void *, const char *) __exported; 221 void *dlvsym(void *, const char *, const char *) __exported; 222 int dladdr(const void *, Dl_info *) __exported; 223 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *), 224 void (*)(void *), void (*)(void *), void (*)(void *)) __exported; 225 int dlinfo(void *, int , void *) __exported; 226 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported; 227 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported; 228 int _rtld_get_stack_prot(void) __exported; 229 int _rtld_is_dlopened(void *) __exported; 230 void _rtld_error(const char *, ...) __exported; 231 232 int npagesizes, osreldate; 233 size_t *pagesizes; 234 235 long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0}; 236 237 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 238 static int max_stack_flags; 239 240 /* 241 * Global declarations normally provided by crt1. The dynamic linker is 242 * not built with crt1, so we have to provide them ourselves. 243 */ 244 char *__progname; 245 char **environ; 246 247 /* 248 * Used to pass argc, argv to init functions. 249 */ 250 int main_argc; 251 char **main_argv; 252 253 /* 254 * Globals to control TLS allocation. 255 */ 256 size_t tls_last_offset; /* Static TLS offset of last module */ 257 size_t tls_last_size; /* Static TLS size of last module */ 258 size_t tls_static_space; /* Static TLS space allocated */ 259 size_t tls_static_max_align; 260 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 261 int tls_max_index = 1; /* Largest module index allocated */ 262 263 bool ld_library_path_rpath = false; 264 265 /* 266 * Fill in a DoneList with an allocation large enough to hold all of 267 * the currently-loaded objects. Keep this as a macro since it calls 268 * alloca and we want that to occur within the scope of the caller. 269 */ 270 #define donelist_init(dlp) \ 271 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 272 assert((dlp)->objs != NULL), \ 273 (dlp)->num_alloc = obj_count, \ 274 (dlp)->num_used = 0) 275 276 #define UTRACE_DLOPEN_START 1 277 #define UTRACE_DLOPEN_STOP 2 278 #define UTRACE_DLCLOSE_START 3 279 #define UTRACE_DLCLOSE_STOP 4 280 #define UTRACE_LOAD_OBJECT 5 281 #define UTRACE_UNLOAD_OBJECT 6 282 #define UTRACE_ADD_RUNDEP 7 283 #define UTRACE_PRELOAD_FINISHED 8 284 #define UTRACE_INIT_CALL 9 285 #define UTRACE_FINI_CALL 10 286 #define UTRACE_DLSYM_START 11 287 #define UTRACE_DLSYM_STOP 12 288 289 struct utrace_rtld { 290 char sig[4]; /* 'RTLD' */ 291 int event; 292 void *handle; 293 void *mapbase; /* Used for 'parent' and 'init/fini' */ 294 size_t mapsize; 295 int refcnt; /* Used for 'mode' */ 296 char name[MAXPATHLEN]; 297 }; 298 299 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 300 if (ld_utrace != NULL) \ 301 ld_utrace_log(e, h, mb, ms, r, n); \ 302 } while (0) 303 304 static void 305 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 306 int refcnt, const char *name) 307 { 308 struct utrace_rtld ut; 309 310 ut.sig[0] = 'R'; 311 ut.sig[1] = 'T'; 312 ut.sig[2] = 'L'; 313 ut.sig[3] = 'D'; 314 ut.event = event; 315 ut.handle = handle; 316 ut.mapbase = mapbase; 317 ut.mapsize = mapsize; 318 ut.refcnt = refcnt; 319 bzero(ut.name, sizeof(ut.name)); 320 if (name) 321 strlcpy(ut.name, name, sizeof(ut.name)); 322 utrace(&ut, sizeof(ut)); 323 } 324 325 /* 326 * Main entry point for dynamic linking. The first argument is the 327 * stack pointer. The stack is expected to be laid out as described 328 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 329 * Specifically, the stack pointer points to a word containing 330 * ARGC. Following that in the stack is a null-terminated sequence 331 * of pointers to argument strings. Then comes a null-terminated 332 * sequence of pointers to environment strings. Finally, there is a 333 * sequence of "auxiliary vector" entries. 334 * 335 * The second argument points to a place to store the dynamic linker's 336 * exit procedure pointer and the third to a place to store the main 337 * program's object. 338 * 339 * The return value is the main program's entry point. 340 */ 341 func_ptr_type 342 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 343 { 344 Elf_Auxinfo *aux_info[AT_COUNT]; 345 int i; 346 int argc; 347 char **argv; 348 char **env; 349 Elf_Auxinfo *aux; 350 Elf_Auxinfo *auxp; 351 const char *argv0; 352 Objlist_Entry *entry; 353 Obj_Entry *obj; 354 Obj_Entry **preload_tail; 355 Obj_Entry *last_interposer; 356 Objlist initlist; 357 RtldLockState lockstate; 358 char *library_path_rpath; 359 int mib[2]; 360 size_t len; 361 362 /* 363 * On entry, the dynamic linker itself has not been relocated yet. 364 * Be very careful not to reference any global data until after 365 * init_rtld has returned. It is OK to reference file-scope statics 366 * and string constants, and to call static and global functions. 367 */ 368 369 /* Find the auxiliary vector on the stack. */ 370 argc = *sp++; 371 argv = (char **) sp; 372 sp += argc + 1; /* Skip over arguments and NULL terminator */ 373 env = (char **) sp; 374 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 375 ; 376 aux = (Elf_Auxinfo *) sp; 377 378 /* Digest the auxiliary vector. */ 379 for (i = 0; i < AT_COUNT; i++) 380 aux_info[i] = NULL; 381 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 382 if (auxp->a_type < AT_COUNT) 383 aux_info[auxp->a_type] = auxp; 384 } 385 386 /* Initialize and relocate ourselves. */ 387 assert(aux_info[AT_BASE] != NULL); 388 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 389 390 __progname = obj_rtld.path; 391 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 392 environ = env; 393 main_argc = argc; 394 main_argv = argv; 395 396 if (aux_info[AT_CANARY] != NULL && 397 aux_info[AT_CANARY]->a_un.a_ptr != NULL) { 398 i = aux_info[AT_CANARYLEN]->a_un.a_val; 399 if (i > sizeof(__stack_chk_guard)) 400 i = sizeof(__stack_chk_guard); 401 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i); 402 } else { 403 mib[0] = CTL_KERN; 404 mib[1] = KERN_ARND; 405 406 len = sizeof(__stack_chk_guard); 407 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 || 408 len != sizeof(__stack_chk_guard)) { 409 /* If sysctl was unsuccessful, use the "terminator canary". */ 410 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0; 411 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0; 412 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n'; 413 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255; 414 } 415 } 416 417 trust = !issetugid(); 418 419 ld_bind_now = getenv(LD_ "BIND_NOW"); 420 /* 421 * If the process is tainted, then we un-set the dangerous environment 422 * variables. The process will be marked as tainted until setuid(2) 423 * is called. If any child process calls setuid(2) we do not want any 424 * future processes to honor the potentially un-safe variables. 425 */ 426 if (!trust) { 427 if (unsetenv(LD_ "PRELOAD") || unsetenv(LD_ "LIBMAP") || 428 unsetenv(LD_ "LIBRARY_PATH") || unsetenv(LD_ "LIBRARY_PATH_FDS") || 429 unsetenv(LD_ "LIBMAP_DISABLE") || 430 unsetenv(LD_ "DEBUG") || unsetenv(LD_ "ELF_HINTS_PATH") || 431 unsetenv(LD_ "LOADFLTR") || unsetenv(LD_ "LIBRARY_PATH_RPATH")) { 432 _rtld_error("environment corrupt; aborting"); 433 die(); 434 } 435 } 436 ld_debug = getenv(LD_ "DEBUG"); 437 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL; 438 libmap_override = getenv(LD_ "LIBMAP"); 439 ld_library_path = getenv(LD_ "LIBRARY_PATH"); 440 ld_library_dirs = getenv(LD_ "LIBRARY_PATH_FDS"); 441 ld_preload = getenv(LD_ "PRELOAD"); 442 ld_elf_hints_path = getenv(LD_ "ELF_HINTS_PATH"); 443 ld_loadfltr = getenv(LD_ "LOADFLTR") != NULL; 444 library_path_rpath = getenv(LD_ "LIBRARY_PATH_RPATH"); 445 if (library_path_rpath != NULL) { 446 if (library_path_rpath[0] == 'y' || 447 library_path_rpath[0] == 'Y' || 448 library_path_rpath[0] == '1') 449 ld_library_path_rpath = true; 450 else 451 ld_library_path_rpath = false; 452 } 453 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 454 (ld_library_path != NULL) || (ld_preload != NULL) || 455 (ld_elf_hints_path != NULL) || ld_loadfltr; 456 ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS"); 457 ld_utrace = getenv(LD_ "UTRACE"); 458 459 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 460 ld_elf_hints_path = _PATH_ELF_HINTS; 461 462 if (ld_debug != NULL && *ld_debug != '\0') 463 debug = 1; 464 dbg("%s is initialized, base address = %p", __progname, 465 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 466 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 467 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 468 469 dbg("initializing thread locks"); 470 lockdflt_init(); 471 472 /* 473 * Load the main program, or process its program header if it is 474 * already loaded. 475 */ 476 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */ 477 int fd = aux_info[AT_EXECFD]->a_un.a_val; 478 dbg("loading main program"); 479 obj_main = map_object(fd, argv0, NULL); 480 close(fd); 481 if (obj_main == NULL) 482 die(); 483 max_stack_flags = obj->stack_flags; 484 } else { /* Main program already loaded. */ 485 const Elf_Phdr *phdr; 486 int phnum; 487 caddr_t entry; 488 489 dbg("processing main program's program header"); 490 assert(aux_info[AT_PHDR] != NULL); 491 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 492 assert(aux_info[AT_PHNUM] != NULL); 493 phnum = aux_info[AT_PHNUM]->a_un.a_val; 494 assert(aux_info[AT_PHENT] != NULL); 495 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 496 assert(aux_info[AT_ENTRY] != NULL); 497 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 498 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL) 499 die(); 500 } 501 502 if (aux_info[AT_EXECPATH] != 0) { 503 char *kexecpath; 504 char buf[MAXPATHLEN]; 505 506 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 507 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 508 if (kexecpath[0] == '/') 509 obj_main->path = kexecpath; 510 else if (getcwd(buf, sizeof(buf)) == NULL || 511 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 512 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 513 obj_main->path = xstrdup(argv0); 514 else 515 obj_main->path = xstrdup(buf); 516 } else { 517 dbg("No AT_EXECPATH"); 518 obj_main->path = xstrdup(argv0); 519 } 520 dbg("obj_main path %s", obj_main->path); 521 obj_main->mainprog = true; 522 523 if (aux_info[AT_STACKPROT] != NULL && 524 aux_info[AT_STACKPROT]->a_un.a_val != 0) 525 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 526 527 #ifndef COMPAT_32BIT 528 /* 529 * Get the actual dynamic linker pathname from the executable if 530 * possible. (It should always be possible.) That ensures that 531 * gdb will find the right dynamic linker even if a non-standard 532 * one is being used. 533 */ 534 if (obj_main->interp != NULL && 535 strcmp(obj_main->interp, obj_rtld.path) != 0) { 536 free(obj_rtld.path); 537 obj_rtld.path = xstrdup(obj_main->interp); 538 __progname = obj_rtld.path; 539 } 540 #endif 541 542 digest_dynamic(obj_main, 0); 543 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 544 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 545 obj_main->dynsymcount); 546 547 linkmap_add(obj_main); 548 linkmap_add(&obj_rtld); 549 550 /* Link the main program into the list of objects. */ 551 *obj_tail = obj_main; 552 obj_tail = &obj_main->next; 553 obj_count++; 554 obj_loads++; 555 556 /* Initialize a fake symbol for resolving undefined weak references. */ 557 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 558 sym_zero.st_shndx = SHN_UNDEF; 559 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 560 561 if (!libmap_disable) 562 libmap_disable = (bool)lm_init(libmap_override); 563 564 dbg("loading LD_PRELOAD libraries"); 565 if (load_preload_objects() == -1) 566 die(); 567 preload_tail = obj_tail; 568 569 dbg("loading needed objects"); 570 if (load_needed_objects(obj_main, 0) == -1) 571 die(); 572 573 /* Make a list of all objects loaded at startup. */ 574 last_interposer = obj_main; 575 for (obj = obj_list; obj != NULL; obj = obj->next) { 576 if (obj->z_interpose && obj != obj_main) { 577 objlist_put_after(&list_main, last_interposer, obj); 578 last_interposer = obj; 579 } else { 580 objlist_push_tail(&list_main, obj); 581 } 582 obj->refcount++; 583 } 584 585 dbg("checking for required versions"); 586 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 587 die(); 588 589 if (ld_tracing) { /* We're done */ 590 trace_loaded_objects(obj_main); 591 exit(0); 592 } 593 594 if (getenv(LD_ "DUMP_REL_PRE") != NULL) { 595 dump_relocations(obj_main); 596 exit (0); 597 } 598 599 /* 600 * Processing tls relocations requires having the tls offsets 601 * initialized. Prepare offsets before starting initial 602 * relocation processing. 603 */ 604 dbg("initializing initial thread local storage offsets"); 605 STAILQ_FOREACH(entry, &list_main, link) { 606 /* 607 * Allocate all the initial objects out of the static TLS 608 * block even if they didn't ask for it. 609 */ 610 allocate_tls_offset(entry->obj); 611 } 612 613 if (relocate_objects(obj_main, 614 ld_bind_now != NULL && *ld_bind_now != '\0', 615 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 616 die(); 617 618 dbg("doing copy relocations"); 619 if (do_copy_relocations(obj_main) == -1) 620 die(); 621 622 if (getenv(LD_ "DUMP_REL_POST") != NULL) { 623 dump_relocations(obj_main); 624 exit (0); 625 } 626 627 /* 628 * Setup TLS for main thread. This must be done after the 629 * relocations are processed, since tls initialization section 630 * might be the subject for relocations. 631 */ 632 dbg("initializing initial thread local storage"); 633 allocate_initial_tls(obj_list); 634 635 dbg("initializing key program variables"); 636 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 637 set_program_var("environ", env); 638 set_program_var("__elf_aux_vector", aux); 639 640 /* Make a list of init functions to call. */ 641 objlist_init(&initlist); 642 initlist_add_objects(obj_list, preload_tail, &initlist); 643 644 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 645 646 map_stacks_exec(NULL); 647 648 dbg("resolving ifuncs"); 649 if (resolve_objects_ifunc(obj_main, 650 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY, 651 NULL) == -1) 652 die(); 653 654 if (!obj_main->crt_no_init) { 655 /* 656 * Make sure we don't call the main program's init and fini 657 * functions for binaries linked with old crt1 which calls 658 * _init itself. 659 */ 660 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 661 obj_main->preinit_array = obj_main->init_array = 662 obj_main->fini_array = (Elf_Addr)NULL; 663 } 664 665 wlock_acquire(rtld_bind_lock, &lockstate); 666 if (obj_main->crt_no_init) 667 preinit_main(); 668 objlist_call_init(&initlist, &lockstate); 669 _r_debug_postinit(&obj_main->linkmap); 670 objlist_clear(&initlist); 671 dbg("loading filtees"); 672 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 673 if (ld_loadfltr || obj->z_loadfltr) 674 load_filtees(obj, 0, &lockstate); 675 } 676 lock_release(rtld_bind_lock, &lockstate); 677 678 dbg("transferring control to program entry point = %p", obj_main->entry); 679 680 /* Return the exit procedure and the program entry point. */ 681 *exit_proc = rtld_exit; 682 *objp = obj_main; 683 return (func_ptr_type) obj_main->entry; 684 } 685 686 void * 687 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 688 { 689 void *ptr; 690 Elf_Addr target; 691 692 ptr = (void *)make_function_pointer(def, obj); 693 target = ((Elf_Addr (*)(void))ptr)(); 694 return ((void *)target); 695 } 696 697 Elf_Addr 698 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 699 { 700 const Elf_Rel *rel; 701 const Elf_Sym *def; 702 const Obj_Entry *defobj; 703 Elf_Addr *where; 704 Elf_Addr target; 705 RtldLockState lockstate; 706 707 rlock_acquire(rtld_bind_lock, &lockstate); 708 if (sigsetjmp(lockstate.env, 0) != 0) 709 lock_upgrade(rtld_bind_lock, &lockstate); 710 if (obj->pltrel) 711 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 712 else 713 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 714 715 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 716 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL, 717 &lockstate); 718 if (def == NULL) 719 die(); 720 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 721 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 722 else 723 target = (Elf_Addr)(defobj->relocbase + def->st_value); 724 725 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 726 defobj->strtab + def->st_name, basename(obj->path), 727 (void *)target, basename(defobj->path)); 728 729 /* 730 * Write the new contents for the jmpslot. Note that depending on 731 * architecture, the value which we need to return back to the 732 * lazy binding trampoline may or may not be the target 733 * address. The value returned from reloc_jmpslot() is the value 734 * that the trampoline needs. 735 */ 736 target = reloc_jmpslot(where, target, defobj, obj, rel); 737 lock_release(rtld_bind_lock, &lockstate); 738 return target; 739 } 740 741 /* 742 * Error reporting function. Use it like printf. If formats the message 743 * into a buffer, and sets things up so that the next call to dlerror() 744 * will return the message. 745 */ 746 void 747 _rtld_error(const char *fmt, ...) 748 { 749 static char buf[512]; 750 va_list ap; 751 752 va_start(ap, fmt); 753 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 754 error_message = buf; 755 va_end(ap); 756 } 757 758 /* 759 * Return a dynamically-allocated copy of the current error message, if any. 760 */ 761 static char * 762 errmsg_save(void) 763 { 764 return error_message == NULL ? NULL : xstrdup(error_message); 765 } 766 767 /* 768 * Restore the current error message from a copy which was previously saved 769 * by errmsg_save(). The copy is freed. 770 */ 771 static void 772 errmsg_restore(char *saved_msg) 773 { 774 if (saved_msg == NULL) 775 error_message = NULL; 776 else { 777 _rtld_error("%s", saved_msg); 778 free(saved_msg); 779 } 780 } 781 782 static const char * 783 basename(const char *name) 784 { 785 const char *p = strrchr(name, '/'); 786 return p != NULL ? p + 1 : name; 787 } 788 789 static struct utsname uts; 790 791 static char * 792 origin_subst_one(char *real, const char *kw, const char *subst, 793 bool may_free) 794 { 795 char *p, *p1, *res, *resp; 796 int subst_len, kw_len, subst_count, old_len, new_len; 797 798 kw_len = strlen(kw); 799 800 /* 801 * First, count the number of the keyword occurences, to 802 * preallocate the final string. 803 */ 804 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 805 p1 = strstr(p, kw); 806 if (p1 == NULL) 807 break; 808 } 809 810 /* 811 * If the keyword is not found, just return. 812 */ 813 if (subst_count == 0) 814 return (may_free ? real : xstrdup(real)); 815 816 /* 817 * There is indeed something to substitute. Calculate the 818 * length of the resulting string, and allocate it. 819 */ 820 subst_len = strlen(subst); 821 old_len = strlen(real); 822 new_len = old_len + (subst_len - kw_len) * subst_count; 823 res = xmalloc(new_len + 1); 824 825 /* 826 * Now, execute the substitution loop. 827 */ 828 for (p = real, resp = res, *resp = '\0';;) { 829 p1 = strstr(p, kw); 830 if (p1 != NULL) { 831 /* Copy the prefix before keyword. */ 832 memcpy(resp, p, p1 - p); 833 resp += p1 - p; 834 /* Keyword replacement. */ 835 memcpy(resp, subst, subst_len); 836 resp += subst_len; 837 *resp = '\0'; 838 p = p1 + kw_len; 839 } else 840 break; 841 } 842 843 /* Copy to the end of string and finish. */ 844 strcat(resp, p); 845 if (may_free) 846 free(real); 847 return (res); 848 } 849 850 static char * 851 origin_subst(char *real, const char *origin_path) 852 { 853 char *res1, *res2, *res3, *res4; 854 855 if (uts.sysname[0] == '\0') { 856 if (uname(&uts) != 0) { 857 _rtld_error("utsname failed: %d", errno); 858 return (NULL); 859 } 860 } 861 res1 = origin_subst_one(real, "$ORIGIN", origin_path, false); 862 res2 = origin_subst_one(res1, "$OSNAME", uts.sysname, true); 863 res3 = origin_subst_one(res2, "$OSREL", uts.release, true); 864 res4 = origin_subst_one(res3, "$PLATFORM", uts.machine, true); 865 return (res4); 866 } 867 868 static void 869 die(void) 870 { 871 const char *msg = dlerror(); 872 873 if (msg == NULL) 874 msg = "Fatal error"; 875 rtld_fdputstr(STDERR_FILENO, msg); 876 rtld_fdputchar(STDERR_FILENO, '\n'); 877 _exit(1); 878 } 879 880 /* 881 * Process a shared object's DYNAMIC section, and save the important 882 * information in its Obj_Entry structure. 883 */ 884 static void 885 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 886 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 887 { 888 const Elf_Dyn *dynp; 889 Needed_Entry **needed_tail = &obj->needed; 890 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 891 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 892 const Elf_Hashelt *hashtab; 893 const Elf32_Word *hashval; 894 Elf32_Word bkt, nmaskwords; 895 int bloom_size32; 896 int plttype = DT_REL; 897 898 *dyn_rpath = NULL; 899 *dyn_soname = NULL; 900 *dyn_runpath = NULL; 901 902 obj->bind_now = false; 903 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 904 switch (dynp->d_tag) { 905 906 case DT_REL: 907 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 908 break; 909 910 case DT_RELSZ: 911 obj->relsize = dynp->d_un.d_val; 912 break; 913 914 case DT_RELENT: 915 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 916 break; 917 918 case DT_JMPREL: 919 obj->pltrel = (const Elf_Rel *) 920 (obj->relocbase + dynp->d_un.d_ptr); 921 break; 922 923 case DT_PLTRELSZ: 924 obj->pltrelsize = dynp->d_un.d_val; 925 break; 926 927 case DT_RELA: 928 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 929 break; 930 931 case DT_RELASZ: 932 obj->relasize = dynp->d_un.d_val; 933 break; 934 935 case DT_RELAENT: 936 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 937 break; 938 939 case DT_PLTREL: 940 plttype = dynp->d_un.d_val; 941 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 942 break; 943 944 case DT_SYMTAB: 945 obj->symtab = (const Elf_Sym *) 946 (obj->relocbase + dynp->d_un.d_ptr); 947 break; 948 949 case DT_SYMENT: 950 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 951 break; 952 953 case DT_STRTAB: 954 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 955 break; 956 957 case DT_STRSZ: 958 obj->strsize = dynp->d_un.d_val; 959 break; 960 961 case DT_VERNEED: 962 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 963 dynp->d_un.d_val); 964 break; 965 966 case DT_VERNEEDNUM: 967 obj->verneednum = dynp->d_un.d_val; 968 break; 969 970 case DT_VERDEF: 971 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 972 dynp->d_un.d_val); 973 break; 974 975 case DT_VERDEFNUM: 976 obj->verdefnum = dynp->d_un.d_val; 977 break; 978 979 case DT_VERSYM: 980 obj->versyms = (const Elf_Versym *)(obj->relocbase + 981 dynp->d_un.d_val); 982 break; 983 984 case DT_HASH: 985 { 986 hashtab = (const Elf_Hashelt *)(obj->relocbase + 987 dynp->d_un.d_ptr); 988 obj->nbuckets = hashtab[0]; 989 obj->nchains = hashtab[1]; 990 obj->buckets = hashtab + 2; 991 obj->chains = obj->buckets + obj->nbuckets; 992 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 993 obj->buckets != NULL; 994 } 995 break; 996 997 case DT_GNU_HASH: 998 { 999 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1000 dynp->d_un.d_ptr); 1001 obj->nbuckets_gnu = hashtab[0]; 1002 obj->symndx_gnu = hashtab[1]; 1003 nmaskwords = hashtab[2]; 1004 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1005 obj->maskwords_bm_gnu = nmaskwords - 1; 1006 obj->shift2_gnu = hashtab[3]; 1007 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4); 1008 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1009 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1010 obj->symndx_gnu; 1011 /* Number of bitmask words is required to be power of 2 */ 1012 obj->valid_hash_gnu = powerof2(nmaskwords) && 1013 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1014 } 1015 break; 1016 1017 case DT_NEEDED: 1018 if (!obj->rtld) { 1019 Needed_Entry *nep = NEW(Needed_Entry); 1020 nep->name = dynp->d_un.d_val; 1021 nep->obj = NULL; 1022 nep->next = NULL; 1023 1024 *needed_tail = nep; 1025 needed_tail = &nep->next; 1026 } 1027 break; 1028 1029 case DT_FILTER: 1030 if (!obj->rtld) { 1031 Needed_Entry *nep = NEW(Needed_Entry); 1032 nep->name = dynp->d_un.d_val; 1033 nep->obj = NULL; 1034 nep->next = NULL; 1035 1036 *needed_filtees_tail = nep; 1037 needed_filtees_tail = &nep->next; 1038 } 1039 break; 1040 1041 case DT_AUXILIARY: 1042 if (!obj->rtld) { 1043 Needed_Entry *nep = NEW(Needed_Entry); 1044 nep->name = dynp->d_un.d_val; 1045 nep->obj = NULL; 1046 nep->next = NULL; 1047 1048 *needed_aux_filtees_tail = nep; 1049 needed_aux_filtees_tail = &nep->next; 1050 } 1051 break; 1052 1053 case DT_PLTGOT: 1054 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 1055 break; 1056 1057 case DT_TEXTREL: 1058 obj->textrel = true; 1059 break; 1060 1061 case DT_SYMBOLIC: 1062 obj->symbolic = true; 1063 break; 1064 1065 case DT_RPATH: 1066 /* 1067 * We have to wait until later to process this, because we 1068 * might not have gotten the address of the string table yet. 1069 */ 1070 *dyn_rpath = dynp; 1071 break; 1072 1073 case DT_SONAME: 1074 *dyn_soname = dynp; 1075 break; 1076 1077 case DT_RUNPATH: 1078 *dyn_runpath = dynp; 1079 break; 1080 1081 case DT_INIT: 1082 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1083 break; 1084 1085 case DT_PREINIT_ARRAY: 1086 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1087 break; 1088 1089 case DT_PREINIT_ARRAYSZ: 1090 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1091 break; 1092 1093 case DT_INIT_ARRAY: 1094 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1095 break; 1096 1097 case DT_INIT_ARRAYSZ: 1098 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1099 break; 1100 1101 case DT_FINI: 1102 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1103 break; 1104 1105 case DT_FINI_ARRAY: 1106 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1107 break; 1108 1109 case DT_FINI_ARRAYSZ: 1110 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1111 break; 1112 1113 /* 1114 * Don't process DT_DEBUG on MIPS as the dynamic section 1115 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1116 */ 1117 1118 #ifndef __mips__ 1119 case DT_DEBUG: 1120 /* XXX - not implemented yet */ 1121 if (!early) 1122 dbg("Filling in DT_DEBUG entry"); 1123 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 1124 break; 1125 #endif 1126 1127 case DT_FLAGS: 1128 if ((dynp->d_un.d_val & DF_ORIGIN) && trust) 1129 obj->z_origin = true; 1130 if (dynp->d_un.d_val & DF_SYMBOLIC) 1131 obj->symbolic = true; 1132 if (dynp->d_un.d_val & DF_TEXTREL) 1133 obj->textrel = true; 1134 if (dynp->d_un.d_val & DF_BIND_NOW) 1135 obj->bind_now = true; 1136 /*if (dynp->d_un.d_val & DF_STATIC_TLS) 1137 ;*/ 1138 break; 1139 #ifdef __mips__ 1140 case DT_MIPS_LOCAL_GOTNO: 1141 obj->local_gotno = dynp->d_un.d_val; 1142 break; 1143 1144 case DT_MIPS_SYMTABNO: 1145 obj->symtabno = dynp->d_un.d_val; 1146 break; 1147 1148 case DT_MIPS_GOTSYM: 1149 obj->gotsym = dynp->d_un.d_val; 1150 break; 1151 1152 case DT_MIPS_RLD_MAP: 1153 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1154 break; 1155 #endif 1156 1157 case DT_FLAGS_1: 1158 if (dynp->d_un.d_val & DF_1_NOOPEN) 1159 obj->z_noopen = true; 1160 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust) 1161 obj->z_origin = true; 1162 /*if (dynp->d_un.d_val & DF_1_GLOBAL) 1163 XXX ;*/ 1164 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1165 obj->bind_now = true; 1166 if (dynp->d_un.d_val & DF_1_NODELETE) 1167 obj->z_nodelete = true; 1168 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1169 obj->z_loadfltr = true; 1170 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1171 obj->z_interpose = true; 1172 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1173 obj->z_nodeflib = true; 1174 break; 1175 1176 default: 1177 if (!early) { 1178 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1179 (long)dynp->d_tag); 1180 } 1181 break; 1182 } 1183 } 1184 1185 obj->traced = false; 1186 1187 if (plttype == DT_RELA) { 1188 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1189 obj->pltrel = NULL; 1190 obj->pltrelasize = obj->pltrelsize; 1191 obj->pltrelsize = 0; 1192 } 1193 1194 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1195 if (obj->valid_hash_sysv) 1196 obj->dynsymcount = obj->nchains; 1197 else if (obj->valid_hash_gnu) { 1198 obj->dynsymcount = 0; 1199 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1200 if (obj->buckets_gnu[bkt] == 0) 1201 continue; 1202 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1203 do 1204 obj->dynsymcount++; 1205 while ((*hashval++ & 1u) == 0); 1206 } 1207 obj->dynsymcount += obj->symndx_gnu; 1208 } 1209 } 1210 1211 static void 1212 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1213 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1214 { 1215 1216 if (obj->z_origin && obj->origin_path == NULL) { 1217 obj->origin_path = xmalloc(PATH_MAX); 1218 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1) 1219 die(); 1220 } 1221 1222 if (dyn_runpath != NULL) { 1223 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val; 1224 if (obj->z_origin) 1225 obj->runpath = origin_subst(obj->runpath, obj->origin_path); 1226 } 1227 else if (dyn_rpath != NULL) { 1228 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 1229 if (obj->z_origin) 1230 obj->rpath = origin_subst(obj->rpath, obj->origin_path); 1231 } 1232 1233 if (dyn_soname != NULL) 1234 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1235 } 1236 1237 static void 1238 digest_dynamic(Obj_Entry *obj, int early) 1239 { 1240 const Elf_Dyn *dyn_rpath; 1241 const Elf_Dyn *dyn_soname; 1242 const Elf_Dyn *dyn_runpath; 1243 1244 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1245 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath); 1246 } 1247 1248 /* 1249 * Process a shared object's program header. This is used only for the 1250 * main program, when the kernel has already loaded the main program 1251 * into memory before calling the dynamic linker. It creates and 1252 * returns an Obj_Entry structure. 1253 */ 1254 static Obj_Entry * 1255 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1256 { 1257 Obj_Entry *obj; 1258 const Elf_Phdr *phlimit = phdr + phnum; 1259 const Elf_Phdr *ph; 1260 Elf_Addr note_start, note_end; 1261 int nsegs = 0; 1262 1263 obj = obj_new(); 1264 for (ph = phdr; ph < phlimit; ph++) { 1265 if (ph->p_type != PT_PHDR) 1266 continue; 1267 1268 obj->phdr = phdr; 1269 obj->phsize = ph->p_memsz; 1270 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1271 break; 1272 } 1273 1274 obj->stack_flags = PF_X | PF_R | PF_W; 1275 1276 for (ph = phdr; ph < phlimit; ph++) { 1277 switch (ph->p_type) { 1278 1279 case PT_INTERP: 1280 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1281 break; 1282 1283 case PT_LOAD: 1284 if (nsegs == 0) { /* First load segment */ 1285 obj->vaddrbase = trunc_page(ph->p_vaddr); 1286 obj->mapbase = obj->vaddrbase + obj->relocbase; 1287 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1288 obj->vaddrbase; 1289 } else { /* Last load segment */ 1290 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1291 obj->vaddrbase; 1292 } 1293 nsegs++; 1294 break; 1295 1296 case PT_DYNAMIC: 1297 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1298 break; 1299 1300 case PT_TLS: 1301 obj->tlsindex = 1; 1302 obj->tlssize = ph->p_memsz; 1303 obj->tlsalign = ph->p_align; 1304 obj->tlsinitsize = ph->p_filesz; 1305 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1306 break; 1307 1308 case PT_GNU_STACK: 1309 obj->stack_flags = ph->p_flags; 1310 break; 1311 1312 case PT_GNU_RELRO: 1313 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1314 obj->relro_size = round_page(ph->p_memsz); 1315 break; 1316 1317 case PT_NOTE: 1318 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1319 note_end = note_start + ph->p_filesz; 1320 digest_notes(obj, note_start, note_end); 1321 break; 1322 } 1323 } 1324 if (nsegs < 1) { 1325 _rtld_error("%s: too few PT_LOAD segments", path); 1326 return NULL; 1327 } 1328 1329 obj->entry = entry; 1330 return obj; 1331 } 1332 1333 void 1334 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1335 { 1336 const Elf_Note *note; 1337 const char *note_name; 1338 uintptr_t p; 1339 1340 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1341 note = (const Elf_Note *)((const char *)(note + 1) + 1342 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1343 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1344 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1345 note->n_descsz != sizeof(int32_t)) 1346 continue; 1347 if (note->n_type != ABI_NOTETYPE && 1348 note->n_type != CRT_NOINIT_NOTETYPE) 1349 continue; 1350 note_name = (const char *)(note + 1); 1351 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1352 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1353 continue; 1354 switch (note->n_type) { 1355 case ABI_NOTETYPE: 1356 /* FreeBSD osrel note */ 1357 p = (uintptr_t)(note + 1); 1358 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1359 obj->osrel = *(const int32_t *)(p); 1360 dbg("note osrel %d", obj->osrel); 1361 break; 1362 case CRT_NOINIT_NOTETYPE: 1363 /* FreeBSD 'crt does not call init' note */ 1364 obj->crt_no_init = true; 1365 dbg("note crt_no_init"); 1366 break; 1367 } 1368 } 1369 } 1370 1371 static Obj_Entry * 1372 dlcheck(void *handle) 1373 { 1374 Obj_Entry *obj; 1375 1376 for (obj = obj_list; obj != NULL; obj = obj->next) 1377 if (obj == (Obj_Entry *) handle) 1378 break; 1379 1380 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1381 _rtld_error("Invalid shared object handle %p", handle); 1382 return NULL; 1383 } 1384 return obj; 1385 } 1386 1387 /* 1388 * If the given object is already in the donelist, return true. Otherwise 1389 * add the object to the list and return false. 1390 */ 1391 static bool 1392 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1393 { 1394 unsigned int i; 1395 1396 for (i = 0; i < dlp->num_used; i++) 1397 if (dlp->objs[i] == obj) 1398 return true; 1399 /* 1400 * Our donelist allocation should always be sufficient. But if 1401 * our threads locking isn't working properly, more shared objects 1402 * could have been loaded since we allocated the list. That should 1403 * never happen, but we'll handle it properly just in case it does. 1404 */ 1405 if (dlp->num_used < dlp->num_alloc) 1406 dlp->objs[dlp->num_used++] = obj; 1407 return false; 1408 } 1409 1410 /* 1411 * Hash function for symbol table lookup. Don't even think about changing 1412 * this. It is specified by the System V ABI. 1413 */ 1414 unsigned long 1415 elf_hash(const char *name) 1416 { 1417 const unsigned char *p = (const unsigned char *) name; 1418 unsigned long h = 0; 1419 unsigned long g; 1420 1421 while (*p != '\0') { 1422 h = (h << 4) + *p++; 1423 if ((g = h & 0xf0000000) != 0) 1424 h ^= g >> 24; 1425 h &= ~g; 1426 } 1427 return h; 1428 } 1429 1430 /* 1431 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1432 * unsigned in case it's implemented with a wider type. 1433 */ 1434 static uint32_t 1435 gnu_hash(const char *s) 1436 { 1437 uint32_t h; 1438 unsigned char c; 1439 1440 h = 5381; 1441 for (c = *s; c != '\0'; c = *++s) 1442 h = h * 33 + c; 1443 return (h & 0xffffffff); 1444 } 1445 1446 1447 /* 1448 * Find the library with the given name, and return its full pathname. 1449 * The returned string is dynamically allocated. Generates an error 1450 * message and returns NULL if the library cannot be found. 1451 * 1452 * If the second argument is non-NULL, then it refers to an already- 1453 * loaded shared object, whose library search path will be searched. 1454 * 1455 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1456 * descriptor (which is close-on-exec) will be passed out via the third 1457 * argument. 1458 * 1459 * The search order is: 1460 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1461 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1462 * LD_LIBRARY_PATH 1463 * DT_RUNPATH in the referencing file 1464 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1465 * from list) 1466 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1467 * 1468 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1469 */ 1470 static char * 1471 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1472 { 1473 char *pathname; 1474 char *name; 1475 bool nodeflib, objgiven; 1476 1477 objgiven = refobj != NULL; 1478 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */ 1479 if (xname[0] != '/' && !trust) { 1480 _rtld_error("Absolute pathname required for shared object \"%s\"", 1481 xname); 1482 return NULL; 1483 } 1484 if (objgiven && refobj->z_origin) { 1485 return (origin_subst(__DECONST(char *, xname), 1486 refobj->origin_path)); 1487 } else { 1488 return (xstrdup(xname)); 1489 } 1490 } 1491 1492 if (libmap_disable || !objgiven || 1493 (name = lm_find(refobj->path, xname)) == NULL) 1494 name = (char *)xname; 1495 1496 dbg(" Searching for \"%s\"", name); 1497 1498 /* 1499 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1500 * back to pre-conforming behaviour if user requested so with 1501 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1502 * nodeflib. 1503 */ 1504 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1505 if ((pathname = search_library_path(name, ld_library_path)) != NULL || 1506 (refobj != NULL && 1507 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1508 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL || 1509 (pathname = search_library_path(name, gethints(false))) != NULL || 1510 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL) 1511 return (pathname); 1512 } else { 1513 nodeflib = objgiven ? refobj->z_nodeflib : false; 1514 if ((objgiven && 1515 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1516 (objgiven && refobj->runpath == NULL && refobj != obj_main && 1517 (pathname = search_library_path(name, obj_main->rpath)) != NULL) || 1518 (pathname = search_library_path(name, ld_library_path)) != NULL || 1519 (objgiven && 1520 (pathname = search_library_path(name, refobj->runpath)) != NULL) || 1521 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL || 1522 (pathname = search_library_path(name, gethints(nodeflib))) != NULL || 1523 (objgiven && !nodeflib && 1524 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)) 1525 return (pathname); 1526 } 1527 1528 if (objgiven && refobj->path != NULL) { 1529 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 1530 name, basename(refobj->path)); 1531 } else { 1532 _rtld_error("Shared object \"%s\" not found", name); 1533 } 1534 return NULL; 1535 } 1536 1537 /* 1538 * Given a symbol number in a referencing object, find the corresponding 1539 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1540 * no definition was found. Returns a pointer to the Obj_Entry of the 1541 * defining object via the reference parameter DEFOBJ_OUT. 1542 */ 1543 const Elf_Sym * 1544 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1545 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1546 RtldLockState *lockstate) 1547 { 1548 const Elf_Sym *ref; 1549 const Elf_Sym *def; 1550 const Obj_Entry *defobj; 1551 SymLook req; 1552 const char *name; 1553 int res; 1554 1555 /* 1556 * If we have already found this symbol, get the information from 1557 * the cache. 1558 */ 1559 if (symnum >= refobj->dynsymcount) 1560 return NULL; /* Bad object */ 1561 if (cache != NULL && cache[symnum].sym != NULL) { 1562 *defobj_out = cache[symnum].obj; 1563 return cache[symnum].sym; 1564 } 1565 1566 ref = refobj->symtab + symnum; 1567 name = refobj->strtab + ref->st_name; 1568 def = NULL; 1569 defobj = NULL; 1570 1571 /* 1572 * We don't have to do a full scale lookup if the symbol is local. 1573 * We know it will bind to the instance in this load module; to 1574 * which we already have a pointer (ie ref). By not doing a lookup, 1575 * we not only improve performance, but it also avoids unresolvable 1576 * symbols when local symbols are not in the hash table. This has 1577 * been seen with the ia64 toolchain. 1578 */ 1579 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1580 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1581 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1582 symnum); 1583 } 1584 symlook_init(&req, name); 1585 req.flags = flags; 1586 req.ventry = fetch_ventry(refobj, symnum); 1587 req.lockstate = lockstate; 1588 res = symlook_default(&req, refobj); 1589 if (res == 0) { 1590 def = req.sym_out; 1591 defobj = req.defobj_out; 1592 } 1593 } else { 1594 def = ref; 1595 defobj = refobj; 1596 } 1597 1598 /* 1599 * If we found no definition and the reference is weak, treat the 1600 * symbol as having the value zero. 1601 */ 1602 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1603 def = &sym_zero; 1604 defobj = obj_main; 1605 } 1606 1607 if (def != NULL) { 1608 *defobj_out = defobj; 1609 /* Record the information in the cache to avoid subsequent lookups. */ 1610 if (cache != NULL) { 1611 cache[symnum].sym = def; 1612 cache[symnum].obj = defobj; 1613 } 1614 } else { 1615 if (refobj != &obj_rtld) 1616 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name); 1617 } 1618 return def; 1619 } 1620 1621 /* 1622 * Return the search path from the ldconfig hints file, reading it if 1623 * necessary. If nostdlib is true, then the default search paths are 1624 * not added to result. 1625 * 1626 * Returns NULL if there are problems with the hints file, 1627 * or if the search path there is empty. 1628 */ 1629 static const char * 1630 gethints(bool nostdlib) 1631 { 1632 static char *hints, *filtered_path; 1633 struct elfhints_hdr hdr; 1634 struct fill_search_info_args sargs, hargs; 1635 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1636 struct dl_serpath *SLPpath, *hintpath; 1637 char *p; 1638 unsigned int SLPndx, hintndx, fndx, fcount; 1639 int fd; 1640 size_t flen; 1641 bool skip; 1642 1643 /* First call, read the hints file */ 1644 if (hints == NULL) { 1645 /* Keep from trying again in case the hints file is bad. */ 1646 hints = ""; 1647 1648 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1649 return (NULL); 1650 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1651 hdr.magic != ELFHINTS_MAGIC || 1652 hdr.version != 1) { 1653 close(fd); 1654 return (NULL); 1655 } 1656 p = xmalloc(hdr.dirlistlen + 1); 1657 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1658 read(fd, p, hdr.dirlistlen + 1) != 1659 (ssize_t)hdr.dirlistlen + 1) { 1660 free(p); 1661 close(fd); 1662 return (NULL); 1663 } 1664 hints = p; 1665 close(fd); 1666 } 1667 1668 /* 1669 * If caller agreed to receive list which includes the default 1670 * paths, we are done. Otherwise, if we still did not 1671 * calculated filtered result, do it now. 1672 */ 1673 if (!nostdlib) 1674 return (hints[0] != '\0' ? hints : NULL); 1675 if (filtered_path != NULL) 1676 goto filt_ret; 1677 1678 /* 1679 * Obtain the list of all configured search paths, and the 1680 * list of the default paths. 1681 * 1682 * First estimate the size of the results. 1683 */ 1684 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1685 smeta.dls_cnt = 0; 1686 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1687 hmeta.dls_cnt = 0; 1688 1689 sargs.request = RTLD_DI_SERINFOSIZE; 1690 sargs.serinfo = &smeta; 1691 hargs.request = RTLD_DI_SERINFOSIZE; 1692 hargs.serinfo = &hmeta; 1693 1694 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1695 path_enumerate(p, fill_search_info, &hargs); 1696 1697 SLPinfo = xmalloc(smeta.dls_size); 1698 hintinfo = xmalloc(hmeta.dls_size); 1699 1700 /* 1701 * Next fetch both sets of paths. 1702 */ 1703 sargs.request = RTLD_DI_SERINFO; 1704 sargs.serinfo = SLPinfo; 1705 sargs.serpath = &SLPinfo->dls_serpath[0]; 1706 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1707 1708 hargs.request = RTLD_DI_SERINFO; 1709 hargs.serinfo = hintinfo; 1710 hargs.serpath = &hintinfo->dls_serpath[0]; 1711 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1712 1713 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1714 path_enumerate(p, fill_search_info, &hargs); 1715 1716 /* 1717 * Now calculate the difference between two sets, by excluding 1718 * standard paths from the full set. 1719 */ 1720 fndx = 0; 1721 fcount = 0; 1722 filtered_path = xmalloc(hdr.dirlistlen + 1); 1723 hintpath = &hintinfo->dls_serpath[0]; 1724 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1725 skip = false; 1726 SLPpath = &SLPinfo->dls_serpath[0]; 1727 /* 1728 * Check each standard path against current. 1729 */ 1730 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1731 /* matched, skip the path */ 1732 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1733 skip = true; 1734 break; 1735 } 1736 } 1737 if (skip) 1738 continue; 1739 /* 1740 * Not matched against any standard path, add the path 1741 * to result. Separate consequtive paths with ':'. 1742 */ 1743 if (fcount > 0) { 1744 filtered_path[fndx] = ':'; 1745 fndx++; 1746 } 1747 fcount++; 1748 flen = strlen(hintpath->dls_name); 1749 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1750 fndx += flen; 1751 } 1752 filtered_path[fndx] = '\0'; 1753 1754 free(SLPinfo); 1755 free(hintinfo); 1756 1757 filt_ret: 1758 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1759 } 1760 1761 static void 1762 init_dag(Obj_Entry *root) 1763 { 1764 const Needed_Entry *needed; 1765 const Objlist_Entry *elm; 1766 DoneList donelist; 1767 1768 if (root->dag_inited) 1769 return; 1770 donelist_init(&donelist); 1771 1772 /* Root object belongs to own DAG. */ 1773 objlist_push_tail(&root->dldags, root); 1774 objlist_push_tail(&root->dagmembers, root); 1775 donelist_check(&donelist, root); 1776 1777 /* 1778 * Add dependencies of root object to DAG in breadth order 1779 * by exploiting the fact that each new object get added 1780 * to the tail of the dagmembers list. 1781 */ 1782 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1783 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1784 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1785 continue; 1786 objlist_push_tail(&needed->obj->dldags, root); 1787 objlist_push_tail(&root->dagmembers, needed->obj); 1788 } 1789 } 1790 root->dag_inited = true; 1791 } 1792 1793 static void 1794 process_nodelete(Obj_Entry *root) 1795 { 1796 const Objlist_Entry *elm; 1797 1798 /* 1799 * Walk over object DAG and process every dependent object that 1800 * is marked as DF_1_NODELETE. They need to grow their own DAG, 1801 * which then should have its reference upped separately. 1802 */ 1803 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1804 if (elm->obj != NULL && elm->obj->z_nodelete && 1805 !elm->obj->ref_nodel) { 1806 dbg("obj %s nodelete", elm->obj->path); 1807 init_dag(elm->obj); 1808 ref_dag(elm->obj); 1809 elm->obj->ref_nodel = true; 1810 } 1811 } 1812 } 1813 /* 1814 * Initialize the dynamic linker. The argument is the address at which 1815 * the dynamic linker has been mapped into memory. The primary task of 1816 * this function is to relocate the dynamic linker. 1817 */ 1818 static void 1819 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 1820 { 1821 Obj_Entry objtmp; /* Temporary rtld object */ 1822 const Elf_Dyn *dyn_rpath; 1823 const Elf_Dyn *dyn_soname; 1824 const Elf_Dyn *dyn_runpath; 1825 1826 #ifdef RTLD_INIT_PAGESIZES_EARLY 1827 /* The page size is required by the dynamic memory allocator. */ 1828 init_pagesizes(aux_info); 1829 #endif 1830 1831 /* 1832 * Conjure up an Obj_Entry structure for the dynamic linker. 1833 * 1834 * The "path" member can't be initialized yet because string constants 1835 * cannot yet be accessed. Below we will set it correctly. 1836 */ 1837 memset(&objtmp, 0, sizeof(objtmp)); 1838 objtmp.path = NULL; 1839 objtmp.rtld = true; 1840 objtmp.mapbase = mapbase; 1841 #ifdef PIC 1842 objtmp.relocbase = mapbase; 1843 #endif 1844 if (RTLD_IS_DYNAMIC()) { 1845 objtmp.dynamic = rtld_dynamic(&objtmp); 1846 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 1847 assert(objtmp.needed == NULL); 1848 #if !defined(__mips__) 1849 /* MIPS has a bogus DT_TEXTREL. */ 1850 assert(!objtmp.textrel); 1851 #endif 1852 1853 /* 1854 * Temporarily put the dynamic linker entry into the object list, so 1855 * that symbols can be found. 1856 */ 1857 1858 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 1859 } 1860 1861 /* Initialize the object list. */ 1862 obj_tail = &obj_list; 1863 1864 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1865 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1866 1867 #ifndef RTLD_INIT_PAGESIZES_EARLY 1868 /* The page size is required by the dynamic memory allocator. */ 1869 init_pagesizes(aux_info); 1870 #endif 1871 1872 if (aux_info[AT_OSRELDATE] != NULL) 1873 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 1874 1875 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 1876 1877 /* Replace the path with a dynamically allocated copy. */ 1878 obj_rtld.path = xstrdup(PATH_RTLD); 1879 1880 r_debug.r_brk = r_debug_state; 1881 r_debug.r_state = RT_CONSISTENT; 1882 } 1883 1884 /* 1885 * Retrieve the array of supported page sizes. The kernel provides the page 1886 * sizes in increasing order. 1887 */ 1888 static void 1889 init_pagesizes(Elf_Auxinfo **aux_info) 1890 { 1891 static size_t psa[MAXPAGESIZES]; 1892 int mib[2]; 1893 size_t len, size; 1894 1895 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 1896 NULL) { 1897 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 1898 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 1899 } else { 1900 len = 2; 1901 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 1902 size = sizeof(psa); 1903 else { 1904 /* As a fallback, retrieve the base page size. */ 1905 size = sizeof(psa[0]); 1906 if (aux_info[AT_PAGESZ] != NULL) { 1907 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 1908 goto psa_filled; 1909 } else { 1910 mib[0] = CTL_HW; 1911 mib[1] = HW_PAGESIZE; 1912 len = 2; 1913 } 1914 } 1915 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 1916 _rtld_error("sysctl for hw.pagesize(s) failed"); 1917 die(); 1918 } 1919 psa_filled: 1920 pagesizes = psa; 1921 } 1922 npagesizes = size / sizeof(pagesizes[0]); 1923 /* Discard any invalid entries at the end of the array. */ 1924 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 1925 npagesizes--; 1926 } 1927 1928 /* 1929 * Add the init functions from a needed object list (and its recursive 1930 * needed objects) to "list". This is not used directly; it is a helper 1931 * function for initlist_add_objects(). The write lock must be held 1932 * when this function is called. 1933 */ 1934 static void 1935 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 1936 { 1937 /* Recursively process the successor needed objects. */ 1938 if (needed->next != NULL) 1939 initlist_add_neededs(needed->next, list); 1940 1941 /* Process the current needed object. */ 1942 if (needed->obj != NULL) 1943 initlist_add_objects(needed->obj, &needed->obj->next, list); 1944 } 1945 1946 /* 1947 * Scan all of the DAGs rooted in the range of objects from "obj" to 1948 * "tail" and add their init functions to "list". This recurses over 1949 * the DAGs and ensure the proper init ordering such that each object's 1950 * needed libraries are initialized before the object itself. At the 1951 * same time, this function adds the objects to the global finalization 1952 * list "list_fini" in the opposite order. The write lock must be 1953 * held when this function is called. 1954 */ 1955 static void 1956 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list) 1957 { 1958 1959 if (obj->init_scanned || obj->init_done) 1960 return; 1961 obj->init_scanned = true; 1962 1963 /* Recursively process the successor objects. */ 1964 if (&obj->next != tail) 1965 initlist_add_objects(obj->next, tail, list); 1966 1967 /* Recursively process the needed objects. */ 1968 if (obj->needed != NULL) 1969 initlist_add_neededs(obj->needed, list); 1970 if (obj->needed_filtees != NULL) 1971 initlist_add_neededs(obj->needed_filtees, list); 1972 if (obj->needed_aux_filtees != NULL) 1973 initlist_add_neededs(obj->needed_aux_filtees, list); 1974 1975 /* Add the object to the init list. */ 1976 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL || 1977 obj->init_array != (Elf_Addr)NULL) 1978 objlist_push_tail(list, obj); 1979 1980 /* Add the object to the global fini list in the reverse order. */ 1981 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 1982 && !obj->on_fini_list) { 1983 objlist_push_head(&list_fini, obj); 1984 obj->on_fini_list = true; 1985 } 1986 } 1987 1988 #ifndef FPTR_TARGET 1989 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 1990 #endif 1991 1992 static void 1993 free_needed_filtees(Needed_Entry *n) 1994 { 1995 Needed_Entry *needed, *needed1; 1996 1997 for (needed = n; needed != NULL; needed = needed->next) { 1998 if (needed->obj != NULL) { 1999 dlclose(needed->obj); 2000 needed->obj = NULL; 2001 } 2002 } 2003 for (needed = n; needed != NULL; needed = needed1) { 2004 needed1 = needed->next; 2005 free(needed); 2006 } 2007 } 2008 2009 static void 2010 unload_filtees(Obj_Entry *obj) 2011 { 2012 2013 free_needed_filtees(obj->needed_filtees); 2014 obj->needed_filtees = NULL; 2015 free_needed_filtees(obj->needed_aux_filtees); 2016 obj->needed_aux_filtees = NULL; 2017 obj->filtees_loaded = false; 2018 } 2019 2020 static void 2021 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2022 RtldLockState *lockstate) 2023 { 2024 2025 for (; needed != NULL; needed = needed->next) { 2026 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2027 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2028 RTLD_LOCAL, lockstate); 2029 } 2030 } 2031 2032 static void 2033 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2034 { 2035 2036 lock_restart_for_upgrade(lockstate); 2037 if (!obj->filtees_loaded) { 2038 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2039 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2040 obj->filtees_loaded = true; 2041 } 2042 } 2043 2044 static int 2045 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2046 { 2047 Obj_Entry *obj1; 2048 2049 for (; needed != NULL; needed = needed->next) { 2050 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2051 flags & ~RTLD_LO_NOLOAD); 2052 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2053 return (-1); 2054 } 2055 return (0); 2056 } 2057 2058 /* 2059 * Given a shared object, traverse its list of needed objects, and load 2060 * each of them. Returns 0 on success. Generates an error message and 2061 * returns -1 on failure. 2062 */ 2063 static int 2064 load_needed_objects(Obj_Entry *first, int flags) 2065 { 2066 Obj_Entry *obj; 2067 2068 for (obj = first; obj != NULL; obj = obj->next) { 2069 if (process_needed(obj, obj->needed, flags) == -1) 2070 return (-1); 2071 } 2072 return (0); 2073 } 2074 2075 static int 2076 load_preload_objects(void) 2077 { 2078 char *p = ld_preload; 2079 Obj_Entry *obj; 2080 static const char delim[] = " \t:;"; 2081 2082 if (p == NULL) 2083 return 0; 2084 2085 p += strspn(p, delim); 2086 while (*p != '\0') { 2087 size_t len = strcspn(p, delim); 2088 char savech; 2089 2090 savech = p[len]; 2091 p[len] = '\0'; 2092 obj = load_object(p, -1, NULL, 0); 2093 if (obj == NULL) 2094 return -1; /* XXX - cleanup */ 2095 obj->z_interpose = true; 2096 p[len] = savech; 2097 p += len; 2098 p += strspn(p, delim); 2099 } 2100 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2101 return 0; 2102 } 2103 2104 static const char * 2105 printable_path(const char *path) 2106 { 2107 2108 return (path == NULL ? "<unknown>" : path); 2109 } 2110 2111 /* 2112 * Load a shared object into memory, if it is not already loaded. The 2113 * object may be specified by name or by user-supplied file descriptor 2114 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2115 * duplicate is. 2116 * 2117 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2118 * on failure. 2119 */ 2120 static Obj_Entry * 2121 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2122 { 2123 Obj_Entry *obj; 2124 int fd; 2125 struct stat sb; 2126 char *path; 2127 2128 fd = -1; 2129 if (name != NULL) { 2130 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 2131 if (object_match_name(obj, name)) 2132 return (obj); 2133 } 2134 2135 path = find_library(name, refobj, &fd); 2136 if (path == NULL) 2137 return (NULL); 2138 } else 2139 path = NULL; 2140 2141 if (fd >= 0) { 2142 /* 2143 * search_library_pathfds() opens a fresh file descriptor for the 2144 * library, so there is no need to dup(). 2145 */ 2146 } else if (fd_u == -1) { 2147 /* 2148 * If we didn't find a match by pathname, or the name is not 2149 * supplied, open the file and check again by device and inode. 2150 * This avoids false mismatches caused by multiple links or ".." 2151 * in pathnames. 2152 * 2153 * To avoid a race, we open the file and use fstat() rather than 2154 * using stat(). 2155 */ 2156 if ((fd = open(path, O_RDONLY | O_CLOEXEC)) == -1) { 2157 _rtld_error("Cannot open \"%s\"", path); 2158 free(path); 2159 return (NULL); 2160 } 2161 } else { 2162 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2163 if (fd == -1) { 2164 _rtld_error("Cannot dup fd"); 2165 free(path); 2166 return (NULL); 2167 } 2168 } 2169 if (fstat(fd, &sb) == -1) { 2170 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2171 close(fd); 2172 free(path); 2173 return NULL; 2174 } 2175 for (obj = obj_list->next; obj != NULL; obj = obj->next) 2176 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2177 break; 2178 if (obj != NULL && name != NULL) { 2179 object_add_name(obj, name); 2180 free(path); 2181 close(fd); 2182 return obj; 2183 } 2184 if (flags & RTLD_LO_NOLOAD) { 2185 free(path); 2186 close(fd); 2187 return (NULL); 2188 } 2189 2190 /* First use of this object, so we must map it in */ 2191 obj = do_load_object(fd, name, path, &sb, flags); 2192 if (obj == NULL) 2193 free(path); 2194 close(fd); 2195 2196 return obj; 2197 } 2198 2199 static Obj_Entry * 2200 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2201 int flags) 2202 { 2203 Obj_Entry *obj; 2204 struct statfs fs; 2205 2206 /* 2207 * but first, make sure that environment variables haven't been 2208 * used to circumvent the noexec flag on a filesystem. 2209 */ 2210 if (dangerous_ld_env) { 2211 if (fstatfs(fd, &fs) != 0) { 2212 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2213 return NULL; 2214 } 2215 if (fs.f_flags & MNT_NOEXEC) { 2216 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 2217 return NULL; 2218 } 2219 } 2220 dbg("loading \"%s\"", printable_path(path)); 2221 obj = map_object(fd, printable_path(path), sbp); 2222 if (obj == NULL) 2223 return NULL; 2224 2225 /* 2226 * If DT_SONAME is present in the object, digest_dynamic2 already 2227 * added it to the object names. 2228 */ 2229 if (name != NULL) 2230 object_add_name(obj, name); 2231 obj->path = path; 2232 digest_dynamic(obj, 0); 2233 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2234 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2235 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2236 RTLD_LO_DLOPEN) { 2237 dbg("refusing to load non-loadable \"%s\"", obj->path); 2238 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2239 munmap(obj->mapbase, obj->mapsize); 2240 obj_free(obj); 2241 return (NULL); 2242 } 2243 2244 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2245 *obj_tail = obj; 2246 obj_tail = &obj->next; 2247 obj_count++; 2248 obj_loads++; 2249 linkmap_add(obj); /* for GDB & dlinfo() */ 2250 max_stack_flags |= obj->stack_flags; 2251 2252 dbg(" %p .. %p: %s", obj->mapbase, 2253 obj->mapbase + obj->mapsize - 1, obj->path); 2254 if (obj->textrel) 2255 dbg(" WARNING: %s has impure text", obj->path); 2256 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2257 obj->path); 2258 2259 return obj; 2260 } 2261 2262 static Obj_Entry * 2263 obj_from_addr(const void *addr) 2264 { 2265 Obj_Entry *obj; 2266 2267 for (obj = obj_list; obj != NULL; obj = obj->next) { 2268 if (addr < (void *) obj->mapbase) 2269 continue; 2270 if (addr < (void *) (obj->mapbase + obj->mapsize)) 2271 return obj; 2272 } 2273 return NULL; 2274 } 2275 2276 static void 2277 preinit_main(void) 2278 { 2279 Elf_Addr *preinit_addr; 2280 int index; 2281 2282 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2283 if (preinit_addr == NULL) 2284 return; 2285 2286 for (index = 0; index < obj_main->preinit_array_num; index++) { 2287 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2288 dbg("calling preinit function for %s at %p", obj_main->path, 2289 (void *)preinit_addr[index]); 2290 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2291 0, 0, obj_main->path); 2292 call_init_pointer(obj_main, preinit_addr[index]); 2293 } 2294 } 2295 } 2296 2297 /* 2298 * Call the finalization functions for each of the objects in "list" 2299 * belonging to the DAG of "root" and referenced once. If NULL "root" 2300 * is specified, every finalization function will be called regardless 2301 * of the reference count and the list elements won't be freed. All of 2302 * the objects are expected to have non-NULL fini functions. 2303 */ 2304 static void 2305 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2306 { 2307 Objlist_Entry *elm; 2308 char *saved_msg; 2309 Elf_Addr *fini_addr; 2310 int index; 2311 2312 assert(root == NULL || root->refcount == 1); 2313 2314 /* 2315 * Preserve the current error message since a fini function might 2316 * call into the dynamic linker and overwrite it. 2317 */ 2318 saved_msg = errmsg_save(); 2319 do { 2320 STAILQ_FOREACH(elm, list, link) { 2321 if (root != NULL && (elm->obj->refcount != 1 || 2322 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2323 continue; 2324 /* Remove object from fini list to prevent recursive invocation. */ 2325 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2326 /* 2327 * XXX: If a dlopen() call references an object while the 2328 * fini function is in progress, we might end up trying to 2329 * unload the referenced object in dlclose() or the object 2330 * won't be unloaded although its fini function has been 2331 * called. 2332 */ 2333 lock_release(rtld_bind_lock, lockstate); 2334 2335 /* 2336 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2337 * When this happens, DT_FINI_ARRAY is processed first. 2338 */ 2339 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2340 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2341 for (index = elm->obj->fini_array_num - 1; index >= 0; 2342 index--) { 2343 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2344 dbg("calling fini function for %s at %p", 2345 elm->obj->path, (void *)fini_addr[index]); 2346 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2347 (void *)fini_addr[index], 0, 0, elm->obj->path); 2348 call_initfini_pointer(elm->obj, fini_addr[index]); 2349 } 2350 } 2351 } 2352 if (elm->obj->fini != (Elf_Addr)NULL) { 2353 dbg("calling fini function for %s at %p", elm->obj->path, 2354 (void *)elm->obj->fini); 2355 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2356 0, 0, elm->obj->path); 2357 call_initfini_pointer(elm->obj, elm->obj->fini); 2358 } 2359 wlock_acquire(rtld_bind_lock, lockstate); 2360 /* No need to free anything if process is going down. */ 2361 if (root != NULL) 2362 free(elm); 2363 /* 2364 * We must restart the list traversal after every fini call 2365 * because a dlclose() call from the fini function or from 2366 * another thread might have modified the reference counts. 2367 */ 2368 break; 2369 } 2370 } while (elm != NULL); 2371 errmsg_restore(saved_msg); 2372 } 2373 2374 /* 2375 * Call the initialization functions for each of the objects in 2376 * "list". All of the objects are expected to have non-NULL init 2377 * functions. 2378 */ 2379 static void 2380 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2381 { 2382 Objlist_Entry *elm; 2383 Obj_Entry *obj; 2384 char *saved_msg; 2385 Elf_Addr *init_addr; 2386 int index; 2387 2388 /* 2389 * Clean init_scanned flag so that objects can be rechecked and 2390 * possibly initialized earlier if any of vectors called below 2391 * cause the change by using dlopen. 2392 */ 2393 for (obj = obj_list; obj != NULL; obj = obj->next) 2394 obj->init_scanned = false; 2395 2396 /* 2397 * Preserve the current error message since an init function might 2398 * call into the dynamic linker and overwrite it. 2399 */ 2400 saved_msg = errmsg_save(); 2401 STAILQ_FOREACH(elm, list, link) { 2402 if (elm->obj->init_done) /* Initialized early. */ 2403 continue; 2404 /* 2405 * Race: other thread might try to use this object before current 2406 * one completes the initilization. Not much can be done here 2407 * without better locking. 2408 */ 2409 elm->obj->init_done = true; 2410 lock_release(rtld_bind_lock, lockstate); 2411 2412 /* 2413 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2414 * When this happens, DT_INIT is processed first. 2415 */ 2416 if (elm->obj->init != (Elf_Addr)NULL) { 2417 dbg("calling init function for %s at %p", elm->obj->path, 2418 (void *)elm->obj->init); 2419 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2420 0, 0, elm->obj->path); 2421 call_initfini_pointer(elm->obj, elm->obj->init); 2422 } 2423 init_addr = (Elf_Addr *)elm->obj->init_array; 2424 if (init_addr != NULL) { 2425 for (index = 0; index < elm->obj->init_array_num; index++) { 2426 if (init_addr[index] != 0 && init_addr[index] != 1) { 2427 dbg("calling init function for %s at %p", elm->obj->path, 2428 (void *)init_addr[index]); 2429 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2430 (void *)init_addr[index], 0, 0, elm->obj->path); 2431 call_init_pointer(elm->obj, init_addr[index]); 2432 } 2433 } 2434 } 2435 wlock_acquire(rtld_bind_lock, lockstate); 2436 } 2437 errmsg_restore(saved_msg); 2438 } 2439 2440 static void 2441 objlist_clear(Objlist *list) 2442 { 2443 Objlist_Entry *elm; 2444 2445 while (!STAILQ_EMPTY(list)) { 2446 elm = STAILQ_FIRST(list); 2447 STAILQ_REMOVE_HEAD(list, link); 2448 free(elm); 2449 } 2450 } 2451 2452 static Objlist_Entry * 2453 objlist_find(Objlist *list, const Obj_Entry *obj) 2454 { 2455 Objlist_Entry *elm; 2456 2457 STAILQ_FOREACH(elm, list, link) 2458 if (elm->obj == obj) 2459 return elm; 2460 return NULL; 2461 } 2462 2463 static void 2464 objlist_init(Objlist *list) 2465 { 2466 STAILQ_INIT(list); 2467 } 2468 2469 static void 2470 objlist_push_head(Objlist *list, Obj_Entry *obj) 2471 { 2472 Objlist_Entry *elm; 2473 2474 elm = NEW(Objlist_Entry); 2475 elm->obj = obj; 2476 STAILQ_INSERT_HEAD(list, elm, link); 2477 } 2478 2479 static void 2480 objlist_push_tail(Objlist *list, Obj_Entry *obj) 2481 { 2482 Objlist_Entry *elm; 2483 2484 elm = NEW(Objlist_Entry); 2485 elm->obj = obj; 2486 STAILQ_INSERT_TAIL(list, elm, link); 2487 } 2488 2489 static void 2490 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2491 { 2492 Objlist_Entry *elm, *listelm; 2493 2494 STAILQ_FOREACH(listelm, list, link) { 2495 if (listelm->obj == listobj) 2496 break; 2497 } 2498 elm = NEW(Objlist_Entry); 2499 elm->obj = obj; 2500 if (listelm != NULL) 2501 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2502 else 2503 STAILQ_INSERT_TAIL(list, elm, link); 2504 } 2505 2506 static void 2507 objlist_remove(Objlist *list, Obj_Entry *obj) 2508 { 2509 Objlist_Entry *elm; 2510 2511 if ((elm = objlist_find(list, obj)) != NULL) { 2512 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2513 free(elm); 2514 } 2515 } 2516 2517 /* 2518 * Relocate dag rooted in the specified object. 2519 * Returns 0 on success, or -1 on failure. 2520 */ 2521 2522 static int 2523 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2524 int flags, RtldLockState *lockstate) 2525 { 2526 Objlist_Entry *elm; 2527 int error; 2528 2529 error = 0; 2530 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2531 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2532 lockstate); 2533 if (error == -1) 2534 break; 2535 } 2536 return (error); 2537 } 2538 2539 /* 2540 * Relocate single object. 2541 * Returns 0 on success, or -1 on failure. 2542 */ 2543 static int 2544 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2545 int flags, RtldLockState *lockstate) 2546 { 2547 2548 if (obj->relocated) 2549 return (0); 2550 obj->relocated = true; 2551 if (obj != rtldobj) 2552 dbg("relocating \"%s\"", obj->path); 2553 2554 if (obj->symtab == NULL || obj->strtab == NULL || 2555 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2556 _rtld_error("%s: Shared object has no run-time symbol table", 2557 obj->path); 2558 return (-1); 2559 } 2560 2561 if (obj->textrel) { 2562 /* There are relocations to the write-protected text segment. */ 2563 if (mprotect(obj->mapbase, obj->textsize, 2564 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) { 2565 _rtld_error("%s: Cannot write-enable text segment: %s", 2566 obj->path, rtld_strerror(errno)); 2567 return (-1); 2568 } 2569 } 2570 2571 /* Process the non-PLT non-IFUNC relocations. */ 2572 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2573 return (-1); 2574 2575 if (obj->textrel) { /* Re-protected the text segment. */ 2576 if (mprotect(obj->mapbase, obj->textsize, 2577 PROT_READ|PROT_EXEC) == -1) { 2578 _rtld_error("%s: Cannot write-protect text segment: %s", 2579 obj->path, rtld_strerror(errno)); 2580 return (-1); 2581 } 2582 } 2583 2584 /* Set the special PLT or GOT entries. */ 2585 init_pltgot(obj); 2586 2587 /* Process the PLT relocations. */ 2588 if (reloc_plt(obj) == -1) 2589 return (-1); 2590 /* Relocate the jump slots if we are doing immediate binding. */ 2591 if (obj->bind_now || bind_now) 2592 if (reloc_jmpslots(obj, flags, lockstate) == -1) 2593 return (-1); 2594 2595 /* 2596 * Process the non-PLT IFUNC relocations. The relocations are 2597 * processed in two phases, because IFUNC resolvers may 2598 * reference other symbols, which must be readily processed 2599 * before resolvers are called. 2600 */ 2601 if (obj->non_plt_gnu_ifunc && 2602 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate)) 2603 return (-1); 2604 2605 if (obj->relro_size > 0) { 2606 if (mprotect(obj->relro_page, obj->relro_size, 2607 PROT_READ) == -1) { 2608 _rtld_error("%s: Cannot enforce relro protection: %s", 2609 obj->path, rtld_strerror(errno)); 2610 return (-1); 2611 } 2612 } 2613 2614 /* 2615 * Set up the magic number and version in the Obj_Entry. These 2616 * were checked in the crt1.o from the original ElfKit, so we 2617 * set them for backward compatibility. 2618 */ 2619 obj->magic = RTLD_MAGIC; 2620 obj->version = RTLD_VERSION; 2621 2622 return (0); 2623 } 2624 2625 /* 2626 * Relocate newly-loaded shared objects. The argument is a pointer to 2627 * the Obj_Entry for the first such object. All objects from the first 2628 * to the end of the list of objects are relocated. Returns 0 on success, 2629 * or -1 on failure. 2630 */ 2631 static int 2632 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2633 int flags, RtldLockState *lockstate) 2634 { 2635 Obj_Entry *obj; 2636 int error; 2637 2638 for (error = 0, obj = first; obj != NULL; obj = obj->next) { 2639 error = relocate_object(obj, bind_now, rtldobj, flags, 2640 lockstate); 2641 if (error == -1) 2642 break; 2643 } 2644 return (error); 2645 } 2646 2647 /* 2648 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2649 * referencing STT_GNU_IFUNC symbols is postponed till the other 2650 * relocations are done. The indirect functions specified as 2651 * ifunc are allowed to call other symbols, so we need to have 2652 * objects relocated before asking for resolution from indirects. 2653 * 2654 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2655 * instead of the usual lazy handling of PLT slots. It is 2656 * consistent with how GNU does it. 2657 */ 2658 static int 2659 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2660 RtldLockState *lockstate) 2661 { 2662 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2663 return (-1); 2664 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2665 reloc_gnu_ifunc(obj, flags, lockstate) == -1) 2666 return (-1); 2667 return (0); 2668 } 2669 2670 static int 2671 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags, 2672 RtldLockState *lockstate) 2673 { 2674 Obj_Entry *obj; 2675 2676 for (obj = first; obj != NULL; obj = obj->next) { 2677 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1) 2678 return (-1); 2679 } 2680 return (0); 2681 } 2682 2683 static int 2684 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2685 RtldLockState *lockstate) 2686 { 2687 Objlist_Entry *elm; 2688 2689 STAILQ_FOREACH(elm, list, link) { 2690 if (resolve_object_ifunc(elm->obj, bind_now, flags, 2691 lockstate) == -1) 2692 return (-1); 2693 } 2694 return (0); 2695 } 2696 2697 /* 2698 * Cleanup procedure. It will be called (by the atexit mechanism) just 2699 * before the process exits. 2700 */ 2701 static void 2702 rtld_exit(void) 2703 { 2704 RtldLockState lockstate; 2705 2706 wlock_acquire(rtld_bind_lock, &lockstate); 2707 dbg("rtld_exit()"); 2708 objlist_call_fini(&list_fini, NULL, &lockstate); 2709 /* No need to remove the items from the list, since we are exiting. */ 2710 if (!libmap_disable) 2711 lm_fini(); 2712 lock_release(rtld_bind_lock, &lockstate); 2713 } 2714 2715 /* 2716 * Iterate over a search path, translate each element, and invoke the 2717 * callback on the result. 2718 */ 2719 static void * 2720 path_enumerate(const char *path, path_enum_proc callback, void *arg) 2721 { 2722 const char *trans; 2723 if (path == NULL) 2724 return (NULL); 2725 2726 path += strspn(path, ":;"); 2727 while (*path != '\0') { 2728 size_t len; 2729 char *res; 2730 2731 len = strcspn(path, ":;"); 2732 trans = lm_findn(NULL, path, len); 2733 if (trans) 2734 res = callback(trans, strlen(trans), arg); 2735 else 2736 res = callback(path, len, arg); 2737 2738 if (res != NULL) 2739 return (res); 2740 2741 path += len; 2742 path += strspn(path, ":;"); 2743 } 2744 2745 return (NULL); 2746 } 2747 2748 struct try_library_args { 2749 const char *name; 2750 size_t namelen; 2751 char *buffer; 2752 size_t buflen; 2753 }; 2754 2755 static void * 2756 try_library_path(const char *dir, size_t dirlen, void *param) 2757 { 2758 struct try_library_args *arg; 2759 2760 arg = param; 2761 if (*dir == '/' || trust) { 2762 char *pathname; 2763 2764 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 2765 return (NULL); 2766 2767 pathname = arg->buffer; 2768 strncpy(pathname, dir, dirlen); 2769 pathname[dirlen] = '/'; 2770 strcpy(pathname + dirlen + 1, arg->name); 2771 2772 dbg(" Trying \"%s\"", pathname); 2773 if (access(pathname, F_OK) == 0) { /* We found it */ 2774 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 2775 strcpy(pathname, arg->buffer); 2776 return (pathname); 2777 } 2778 } 2779 return (NULL); 2780 } 2781 2782 static char * 2783 search_library_path(const char *name, const char *path) 2784 { 2785 char *p; 2786 struct try_library_args arg; 2787 2788 if (path == NULL) 2789 return NULL; 2790 2791 arg.name = name; 2792 arg.namelen = strlen(name); 2793 arg.buffer = xmalloc(PATH_MAX); 2794 arg.buflen = PATH_MAX; 2795 2796 p = path_enumerate(path, try_library_path, &arg); 2797 2798 free(arg.buffer); 2799 2800 return (p); 2801 } 2802 2803 2804 /* 2805 * Finds the library with the given name using the directory descriptors 2806 * listed in the LD_LIBRARY_PATH_FDS environment variable. 2807 * 2808 * Returns a freshly-opened close-on-exec file descriptor for the library, 2809 * or -1 if the library cannot be found. 2810 */ 2811 static char * 2812 search_library_pathfds(const char *name, const char *path, int *fdp) 2813 { 2814 char *envcopy, *fdstr, *found, *last_token; 2815 size_t len; 2816 int dirfd, fd; 2817 2818 dbg("%s('%s', '%s', fdp)", __func__, name, path); 2819 2820 /* Don't load from user-specified libdirs into setuid binaries. */ 2821 if (!trust) 2822 return (NULL); 2823 2824 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 2825 if (path == NULL) 2826 return (NULL); 2827 2828 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 2829 if (name[0] == '/') { 2830 dbg("Absolute path (%s) passed to %s", name, __func__); 2831 return (NULL); 2832 } 2833 2834 /* 2835 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 2836 * copy of the path, as strtok_r rewrites separator tokens 2837 * with '\0'. 2838 */ 2839 found = NULL; 2840 envcopy = xstrdup(path); 2841 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 2842 fdstr = strtok_r(NULL, ":", &last_token)) { 2843 dirfd = parse_libdir(fdstr); 2844 if (dirfd < 0) 2845 break; 2846 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC); 2847 if (fd >= 0) { 2848 *fdp = fd; 2849 len = strlen(fdstr) + strlen(name) + 3; 2850 found = xmalloc(len); 2851 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 2852 _rtld_error("error generating '%d/%s'", 2853 dirfd, name); 2854 die(); 2855 } 2856 dbg("open('%s') => %d", found, fd); 2857 break; 2858 } 2859 } 2860 free(envcopy); 2861 2862 return (found); 2863 } 2864 2865 2866 int 2867 dlclose(void *handle) 2868 { 2869 Obj_Entry *root; 2870 RtldLockState lockstate; 2871 2872 wlock_acquire(rtld_bind_lock, &lockstate); 2873 root = dlcheck(handle); 2874 if (root == NULL) { 2875 lock_release(rtld_bind_lock, &lockstate); 2876 return -1; 2877 } 2878 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 2879 root->path); 2880 2881 /* Unreference the object and its dependencies. */ 2882 root->dl_refcount--; 2883 2884 if (root->refcount == 1) { 2885 /* 2886 * The object will be no longer referenced, so we must unload it. 2887 * First, call the fini functions. 2888 */ 2889 objlist_call_fini(&list_fini, root, &lockstate); 2890 2891 unref_dag(root); 2892 2893 /* Finish cleaning up the newly-unreferenced objects. */ 2894 GDB_STATE(RT_DELETE,&root->linkmap); 2895 unload_object(root); 2896 GDB_STATE(RT_CONSISTENT,NULL); 2897 } else 2898 unref_dag(root); 2899 2900 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 2901 lock_release(rtld_bind_lock, &lockstate); 2902 return 0; 2903 } 2904 2905 char * 2906 dlerror(void) 2907 { 2908 char *msg = error_message; 2909 error_message = NULL; 2910 return msg; 2911 } 2912 2913 /* 2914 * This function is deprecated and has no effect. 2915 */ 2916 void 2917 dllockinit(void *context, 2918 void *(*lock_create)(void *context), 2919 void (*rlock_acquire)(void *lock), 2920 void (*wlock_acquire)(void *lock), 2921 void (*lock_release)(void *lock), 2922 void (*lock_destroy)(void *lock), 2923 void (*context_destroy)(void *context)) 2924 { 2925 static void *cur_context; 2926 static void (*cur_context_destroy)(void *); 2927 2928 /* Just destroy the context from the previous call, if necessary. */ 2929 if (cur_context_destroy != NULL) 2930 cur_context_destroy(cur_context); 2931 cur_context = context; 2932 cur_context_destroy = context_destroy; 2933 } 2934 2935 void * 2936 dlopen(const char *name, int mode) 2937 { 2938 2939 return (rtld_dlopen(name, -1, mode)); 2940 } 2941 2942 void * 2943 fdlopen(int fd, int mode) 2944 { 2945 2946 return (rtld_dlopen(NULL, fd, mode)); 2947 } 2948 2949 static void * 2950 rtld_dlopen(const char *name, int fd, int mode) 2951 { 2952 RtldLockState lockstate; 2953 int lo_flags; 2954 2955 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 2956 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 2957 if (ld_tracing != NULL) { 2958 rlock_acquire(rtld_bind_lock, &lockstate); 2959 if (sigsetjmp(lockstate.env, 0) != 0) 2960 lock_upgrade(rtld_bind_lock, &lockstate); 2961 environ = (char **)*get_program_var_addr("environ", &lockstate); 2962 lock_release(rtld_bind_lock, &lockstate); 2963 } 2964 lo_flags = RTLD_LO_DLOPEN; 2965 if (mode & RTLD_NODELETE) 2966 lo_flags |= RTLD_LO_NODELETE; 2967 if (mode & RTLD_NOLOAD) 2968 lo_flags |= RTLD_LO_NOLOAD; 2969 if (ld_tracing != NULL) 2970 lo_flags |= RTLD_LO_TRACE; 2971 2972 return (dlopen_object(name, fd, obj_main, lo_flags, 2973 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 2974 } 2975 2976 static void 2977 dlopen_cleanup(Obj_Entry *obj) 2978 { 2979 2980 obj->dl_refcount--; 2981 unref_dag(obj); 2982 if (obj->refcount == 0) 2983 unload_object(obj); 2984 } 2985 2986 static Obj_Entry * 2987 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 2988 int mode, RtldLockState *lockstate) 2989 { 2990 Obj_Entry **old_obj_tail; 2991 Obj_Entry *obj; 2992 Objlist initlist; 2993 RtldLockState mlockstate; 2994 int result; 2995 2996 objlist_init(&initlist); 2997 2998 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 2999 wlock_acquire(rtld_bind_lock, &mlockstate); 3000 lockstate = &mlockstate; 3001 } 3002 GDB_STATE(RT_ADD,NULL); 3003 3004 old_obj_tail = obj_tail; 3005 obj = NULL; 3006 if (name == NULL && fd == -1) { 3007 obj = obj_main; 3008 obj->refcount++; 3009 } else { 3010 obj = load_object(name, fd, refobj, lo_flags); 3011 } 3012 3013 if (obj) { 3014 obj->dl_refcount++; 3015 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3016 objlist_push_tail(&list_global, obj); 3017 if (*old_obj_tail != NULL) { /* We loaded something new. */ 3018 assert(*old_obj_tail == obj); 3019 result = load_needed_objects(obj, 3020 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 3021 init_dag(obj); 3022 ref_dag(obj); 3023 if (result != -1) 3024 result = rtld_verify_versions(&obj->dagmembers); 3025 if (result != -1 && ld_tracing) 3026 goto trace; 3027 if (result == -1 || relocate_object_dag(obj, 3028 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3029 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3030 lockstate) == -1) { 3031 dlopen_cleanup(obj); 3032 obj = NULL; 3033 } else if (lo_flags & RTLD_LO_EARLY) { 3034 /* 3035 * Do not call the init functions for early loaded 3036 * filtees. The image is still not initialized enough 3037 * for them to work. 3038 * 3039 * Our object is found by the global object list and 3040 * will be ordered among all init calls done right 3041 * before transferring control to main. 3042 */ 3043 } else { 3044 /* Make list of init functions to call. */ 3045 initlist_add_objects(obj, &obj->next, &initlist); 3046 } 3047 /* 3048 * Process all no_delete objects here, given them own 3049 * DAGs to prevent their dependencies from being unloaded. 3050 * This has to be done after we have loaded all of the 3051 * dependencies, so that we do not miss any. 3052 */ 3053 if (obj != NULL) 3054 process_nodelete(obj); 3055 } else { 3056 /* 3057 * Bump the reference counts for objects on this DAG. If 3058 * this is the first dlopen() call for the object that was 3059 * already loaded as a dependency, initialize the dag 3060 * starting at it. 3061 */ 3062 init_dag(obj); 3063 ref_dag(obj); 3064 3065 if ((lo_flags & RTLD_LO_TRACE) != 0) 3066 goto trace; 3067 } 3068 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3069 obj->z_nodelete) && !obj->ref_nodel) { 3070 dbg("obj %s nodelete", obj->path); 3071 ref_dag(obj); 3072 obj->z_nodelete = obj->ref_nodel = true; 3073 } 3074 } 3075 3076 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3077 name); 3078 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3079 3080 if (!(lo_flags & RTLD_LO_EARLY)) { 3081 map_stacks_exec(lockstate); 3082 } 3083 3084 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3085 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3086 lockstate) == -1) { 3087 objlist_clear(&initlist); 3088 dlopen_cleanup(obj); 3089 if (lockstate == &mlockstate) 3090 lock_release(rtld_bind_lock, lockstate); 3091 return (NULL); 3092 } 3093 3094 if (!(lo_flags & RTLD_LO_EARLY)) { 3095 /* Call the init functions. */ 3096 objlist_call_init(&initlist, lockstate); 3097 } 3098 objlist_clear(&initlist); 3099 if (lockstate == &mlockstate) 3100 lock_release(rtld_bind_lock, lockstate); 3101 return obj; 3102 trace: 3103 trace_loaded_objects(obj); 3104 if (lockstate == &mlockstate) 3105 lock_release(rtld_bind_lock, lockstate); 3106 exit(0); 3107 } 3108 3109 static void * 3110 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3111 int flags) 3112 { 3113 DoneList donelist; 3114 const Obj_Entry *obj, *defobj; 3115 const Elf_Sym *def; 3116 SymLook req; 3117 RtldLockState lockstate; 3118 tls_index ti; 3119 void *sym; 3120 int res; 3121 3122 def = NULL; 3123 defobj = NULL; 3124 symlook_init(&req, name); 3125 req.ventry = ve; 3126 req.flags = flags | SYMLOOK_IN_PLT; 3127 req.lockstate = &lockstate; 3128 3129 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3130 rlock_acquire(rtld_bind_lock, &lockstate); 3131 if (sigsetjmp(lockstate.env, 0) != 0) 3132 lock_upgrade(rtld_bind_lock, &lockstate); 3133 if (handle == NULL || handle == RTLD_NEXT || 3134 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3135 3136 if ((obj = obj_from_addr(retaddr)) == NULL) { 3137 _rtld_error("Cannot determine caller's shared object"); 3138 lock_release(rtld_bind_lock, &lockstate); 3139 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3140 return NULL; 3141 } 3142 if (handle == NULL) { /* Just the caller's shared object. */ 3143 res = symlook_obj(&req, obj); 3144 if (res == 0) { 3145 def = req.sym_out; 3146 defobj = req.defobj_out; 3147 } 3148 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3149 handle == RTLD_SELF) { /* ... caller included */ 3150 if (handle == RTLD_NEXT) 3151 obj = obj->next; 3152 for (; obj != NULL; obj = obj->next) { 3153 res = symlook_obj(&req, obj); 3154 if (res == 0) { 3155 if (def == NULL || 3156 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3157 def = req.sym_out; 3158 defobj = req.defobj_out; 3159 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3160 break; 3161 } 3162 } 3163 } 3164 /* 3165 * Search the dynamic linker itself, and possibly resolve the 3166 * symbol from there. This is how the application links to 3167 * dynamic linker services such as dlopen. 3168 */ 3169 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3170 res = symlook_obj(&req, &obj_rtld); 3171 if (res == 0) { 3172 def = req.sym_out; 3173 defobj = req.defobj_out; 3174 } 3175 } 3176 } else { 3177 assert(handle == RTLD_DEFAULT); 3178 res = symlook_default(&req, obj); 3179 if (res == 0) { 3180 defobj = req.defobj_out; 3181 def = req.sym_out; 3182 } 3183 } 3184 } else { 3185 if ((obj = dlcheck(handle)) == NULL) { 3186 lock_release(rtld_bind_lock, &lockstate); 3187 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3188 return NULL; 3189 } 3190 3191 donelist_init(&donelist); 3192 if (obj->mainprog) { 3193 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3194 res = symlook_global(&req, &donelist); 3195 if (res == 0) { 3196 def = req.sym_out; 3197 defobj = req.defobj_out; 3198 } 3199 /* 3200 * Search the dynamic linker itself, and possibly resolve the 3201 * symbol from there. This is how the application links to 3202 * dynamic linker services such as dlopen. 3203 */ 3204 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3205 res = symlook_obj(&req, &obj_rtld); 3206 if (res == 0) { 3207 def = req.sym_out; 3208 defobj = req.defobj_out; 3209 } 3210 } 3211 } 3212 else { 3213 /* Search the whole DAG rooted at the given object. */ 3214 res = symlook_list(&req, &obj->dagmembers, &donelist); 3215 if (res == 0) { 3216 def = req.sym_out; 3217 defobj = req.defobj_out; 3218 } 3219 } 3220 } 3221 3222 if (def != NULL) { 3223 lock_release(rtld_bind_lock, &lockstate); 3224 3225 /* 3226 * The value required by the caller is derived from the value 3227 * of the symbol. this is simply the relocated value of the 3228 * symbol. 3229 */ 3230 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3231 sym = make_function_pointer(def, defobj); 3232 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3233 sym = rtld_resolve_ifunc(defobj, def); 3234 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3235 ti.ti_module = defobj->tlsindex; 3236 ti.ti_offset = def->st_value; 3237 sym = __tls_get_addr(&ti); 3238 } else 3239 sym = defobj->relocbase + def->st_value; 3240 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3241 return (sym); 3242 } 3243 3244 _rtld_error("Undefined symbol \"%s\"", name); 3245 lock_release(rtld_bind_lock, &lockstate); 3246 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3247 return NULL; 3248 } 3249 3250 void * 3251 dlsym(void *handle, const char *name) 3252 { 3253 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3254 SYMLOOK_DLSYM); 3255 } 3256 3257 dlfunc_t 3258 dlfunc(void *handle, const char *name) 3259 { 3260 union { 3261 void *d; 3262 dlfunc_t f; 3263 } rv; 3264 3265 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3266 SYMLOOK_DLSYM); 3267 return (rv.f); 3268 } 3269 3270 void * 3271 dlvsym(void *handle, const char *name, const char *version) 3272 { 3273 Ver_Entry ventry; 3274 3275 ventry.name = version; 3276 ventry.file = NULL; 3277 ventry.hash = elf_hash(version); 3278 ventry.flags= 0; 3279 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3280 SYMLOOK_DLSYM); 3281 } 3282 3283 int 3284 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3285 { 3286 const Obj_Entry *obj; 3287 RtldLockState lockstate; 3288 3289 rlock_acquire(rtld_bind_lock, &lockstate); 3290 obj = obj_from_addr(addr); 3291 if (obj == NULL) { 3292 _rtld_error("No shared object contains address"); 3293 lock_release(rtld_bind_lock, &lockstate); 3294 return (0); 3295 } 3296 rtld_fill_dl_phdr_info(obj, phdr_info); 3297 lock_release(rtld_bind_lock, &lockstate); 3298 return (1); 3299 } 3300 3301 int 3302 dladdr(const void *addr, Dl_info *info) 3303 { 3304 const Obj_Entry *obj; 3305 const Elf_Sym *def; 3306 void *symbol_addr; 3307 unsigned long symoffset; 3308 RtldLockState lockstate; 3309 3310 rlock_acquire(rtld_bind_lock, &lockstate); 3311 obj = obj_from_addr(addr); 3312 if (obj == NULL) { 3313 _rtld_error("No shared object contains address"); 3314 lock_release(rtld_bind_lock, &lockstate); 3315 return 0; 3316 } 3317 info->dli_fname = obj->path; 3318 info->dli_fbase = obj->mapbase; 3319 info->dli_saddr = (void *)0; 3320 info->dli_sname = NULL; 3321 3322 /* 3323 * Walk the symbol list looking for the symbol whose address is 3324 * closest to the address sent in. 3325 */ 3326 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3327 def = obj->symtab + symoffset; 3328 3329 /* 3330 * For skip the symbol if st_shndx is either SHN_UNDEF or 3331 * SHN_COMMON. 3332 */ 3333 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3334 continue; 3335 3336 /* 3337 * If the symbol is greater than the specified address, or if it 3338 * is further away from addr than the current nearest symbol, 3339 * then reject it. 3340 */ 3341 symbol_addr = obj->relocbase + def->st_value; 3342 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3343 continue; 3344 3345 /* Update our idea of the nearest symbol. */ 3346 info->dli_sname = obj->strtab + def->st_name; 3347 info->dli_saddr = symbol_addr; 3348 3349 /* Exact match? */ 3350 if (info->dli_saddr == addr) 3351 break; 3352 } 3353 lock_release(rtld_bind_lock, &lockstate); 3354 return 1; 3355 } 3356 3357 int 3358 dlinfo(void *handle, int request, void *p) 3359 { 3360 const Obj_Entry *obj; 3361 RtldLockState lockstate; 3362 int error; 3363 3364 rlock_acquire(rtld_bind_lock, &lockstate); 3365 3366 if (handle == NULL || handle == RTLD_SELF) { 3367 void *retaddr; 3368 3369 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3370 if ((obj = obj_from_addr(retaddr)) == NULL) 3371 _rtld_error("Cannot determine caller's shared object"); 3372 } else 3373 obj = dlcheck(handle); 3374 3375 if (obj == NULL) { 3376 lock_release(rtld_bind_lock, &lockstate); 3377 return (-1); 3378 } 3379 3380 error = 0; 3381 switch (request) { 3382 case RTLD_DI_LINKMAP: 3383 *((struct link_map const **)p) = &obj->linkmap; 3384 break; 3385 case RTLD_DI_ORIGIN: 3386 error = rtld_dirname(obj->path, p); 3387 break; 3388 3389 case RTLD_DI_SERINFOSIZE: 3390 case RTLD_DI_SERINFO: 3391 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3392 break; 3393 3394 default: 3395 _rtld_error("Invalid request %d passed to dlinfo()", request); 3396 error = -1; 3397 } 3398 3399 lock_release(rtld_bind_lock, &lockstate); 3400 3401 return (error); 3402 } 3403 3404 static void 3405 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3406 { 3407 3408 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3409 phdr_info->dlpi_name = obj->path; 3410 phdr_info->dlpi_phdr = obj->phdr; 3411 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3412 phdr_info->dlpi_tls_modid = obj->tlsindex; 3413 phdr_info->dlpi_tls_data = obj->tlsinit; 3414 phdr_info->dlpi_adds = obj_loads; 3415 phdr_info->dlpi_subs = obj_loads - obj_count; 3416 } 3417 3418 int 3419 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3420 { 3421 struct dl_phdr_info phdr_info; 3422 const Obj_Entry *obj; 3423 RtldLockState bind_lockstate, phdr_lockstate; 3424 int error; 3425 3426 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3427 rlock_acquire(rtld_bind_lock, &bind_lockstate); 3428 3429 error = 0; 3430 3431 for (obj = obj_list; obj != NULL; obj = obj->next) { 3432 rtld_fill_dl_phdr_info(obj, &phdr_info); 3433 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0) 3434 break; 3435 3436 } 3437 if (error == 0) { 3438 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3439 error = callback(&phdr_info, sizeof(phdr_info), param); 3440 } 3441 3442 lock_release(rtld_bind_lock, &bind_lockstate); 3443 lock_release(rtld_phdr_lock, &phdr_lockstate); 3444 3445 return (error); 3446 } 3447 3448 static void * 3449 fill_search_info(const char *dir, size_t dirlen, void *param) 3450 { 3451 struct fill_search_info_args *arg; 3452 3453 arg = param; 3454 3455 if (arg->request == RTLD_DI_SERINFOSIZE) { 3456 arg->serinfo->dls_cnt ++; 3457 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3458 } else { 3459 struct dl_serpath *s_entry; 3460 3461 s_entry = arg->serpath; 3462 s_entry->dls_name = arg->strspace; 3463 s_entry->dls_flags = arg->flags; 3464 3465 strncpy(arg->strspace, dir, dirlen); 3466 arg->strspace[dirlen] = '\0'; 3467 3468 arg->strspace += dirlen + 1; 3469 arg->serpath++; 3470 } 3471 3472 return (NULL); 3473 } 3474 3475 static int 3476 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3477 { 3478 struct dl_serinfo _info; 3479 struct fill_search_info_args args; 3480 3481 args.request = RTLD_DI_SERINFOSIZE; 3482 args.serinfo = &_info; 3483 3484 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3485 _info.dls_cnt = 0; 3486 3487 path_enumerate(obj->rpath, fill_search_info, &args); 3488 path_enumerate(ld_library_path, fill_search_info, &args); 3489 path_enumerate(obj->runpath, fill_search_info, &args); 3490 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args); 3491 if (!obj->z_nodeflib) 3492 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 3493 3494 3495 if (request == RTLD_DI_SERINFOSIZE) { 3496 info->dls_size = _info.dls_size; 3497 info->dls_cnt = _info.dls_cnt; 3498 return (0); 3499 } 3500 3501 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3502 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3503 return (-1); 3504 } 3505 3506 args.request = RTLD_DI_SERINFO; 3507 args.serinfo = info; 3508 args.serpath = &info->dls_serpath[0]; 3509 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3510 3511 args.flags = LA_SER_RUNPATH; 3512 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 3513 return (-1); 3514 3515 args.flags = LA_SER_LIBPATH; 3516 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 3517 return (-1); 3518 3519 args.flags = LA_SER_RUNPATH; 3520 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL) 3521 return (-1); 3522 3523 args.flags = LA_SER_CONFIG; 3524 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args) 3525 != NULL) 3526 return (-1); 3527 3528 args.flags = LA_SER_DEFAULT; 3529 if (!obj->z_nodeflib && 3530 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 3531 return (-1); 3532 return (0); 3533 } 3534 3535 static int 3536 rtld_dirname(const char *path, char *bname) 3537 { 3538 const char *endp; 3539 3540 /* Empty or NULL string gets treated as "." */ 3541 if (path == NULL || *path == '\0') { 3542 bname[0] = '.'; 3543 bname[1] = '\0'; 3544 return (0); 3545 } 3546 3547 /* Strip trailing slashes */ 3548 endp = path + strlen(path) - 1; 3549 while (endp > path && *endp == '/') 3550 endp--; 3551 3552 /* Find the start of the dir */ 3553 while (endp > path && *endp != '/') 3554 endp--; 3555 3556 /* Either the dir is "/" or there are no slashes */ 3557 if (endp == path) { 3558 bname[0] = *endp == '/' ? '/' : '.'; 3559 bname[1] = '\0'; 3560 return (0); 3561 } else { 3562 do { 3563 endp--; 3564 } while (endp > path && *endp == '/'); 3565 } 3566 3567 if (endp - path + 2 > PATH_MAX) 3568 { 3569 _rtld_error("Filename is too long: %s", path); 3570 return(-1); 3571 } 3572 3573 strncpy(bname, path, endp - path + 1); 3574 bname[endp - path + 1] = '\0'; 3575 return (0); 3576 } 3577 3578 static int 3579 rtld_dirname_abs(const char *path, char *base) 3580 { 3581 char *last; 3582 3583 if (realpath(path, base) == NULL) 3584 return (-1); 3585 dbg("%s -> %s", path, base); 3586 last = strrchr(base, '/'); 3587 if (last == NULL) 3588 return (-1); 3589 if (last != base) 3590 *last = '\0'; 3591 return (0); 3592 } 3593 3594 static void 3595 linkmap_add(Obj_Entry *obj) 3596 { 3597 struct link_map *l = &obj->linkmap; 3598 struct link_map *prev; 3599 3600 obj->linkmap.l_name = obj->path; 3601 obj->linkmap.l_addr = obj->mapbase; 3602 obj->linkmap.l_ld = obj->dynamic; 3603 #ifdef __mips__ 3604 /* GDB needs load offset on MIPS to use the symbols */ 3605 obj->linkmap.l_offs = obj->relocbase; 3606 #endif 3607 3608 if (r_debug.r_map == NULL) { 3609 r_debug.r_map = l; 3610 return; 3611 } 3612 3613 /* 3614 * Scan to the end of the list, but not past the entry for the 3615 * dynamic linker, which we want to keep at the very end. 3616 */ 3617 for (prev = r_debug.r_map; 3618 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3619 prev = prev->l_next) 3620 ; 3621 3622 /* Link in the new entry. */ 3623 l->l_prev = prev; 3624 l->l_next = prev->l_next; 3625 if (l->l_next != NULL) 3626 l->l_next->l_prev = l; 3627 prev->l_next = l; 3628 } 3629 3630 static void 3631 linkmap_delete(Obj_Entry *obj) 3632 { 3633 struct link_map *l = &obj->linkmap; 3634 3635 if (l->l_prev == NULL) { 3636 if ((r_debug.r_map = l->l_next) != NULL) 3637 l->l_next->l_prev = NULL; 3638 return; 3639 } 3640 3641 if ((l->l_prev->l_next = l->l_next) != NULL) 3642 l->l_next->l_prev = l->l_prev; 3643 } 3644 3645 /* 3646 * Function for the debugger to set a breakpoint on to gain control. 3647 * 3648 * The two parameters allow the debugger to easily find and determine 3649 * what the runtime loader is doing and to whom it is doing it. 3650 * 3651 * When the loadhook trap is hit (r_debug_state, set at program 3652 * initialization), the arguments can be found on the stack: 3653 * 3654 * +8 struct link_map *m 3655 * +4 struct r_debug *rd 3656 * +0 RetAddr 3657 */ 3658 void 3659 r_debug_state(struct r_debug* rd, struct link_map *m) 3660 { 3661 /* 3662 * The following is a hack to force the compiler to emit calls to 3663 * this function, even when optimizing. If the function is empty, 3664 * the compiler is not obliged to emit any code for calls to it, 3665 * even when marked __noinline. However, gdb depends on those 3666 * calls being made. 3667 */ 3668 __compiler_membar(); 3669 } 3670 3671 /* 3672 * A function called after init routines have completed. This can be used to 3673 * break before a program's entry routine is called, and can be used when 3674 * main is not available in the symbol table. 3675 */ 3676 void 3677 _r_debug_postinit(struct link_map *m) 3678 { 3679 3680 /* See r_debug_state(). */ 3681 __compiler_membar(); 3682 } 3683 3684 /* 3685 * Get address of the pointer variable in the main program. 3686 * Prefer non-weak symbol over the weak one. 3687 */ 3688 static const void ** 3689 get_program_var_addr(const char *name, RtldLockState *lockstate) 3690 { 3691 SymLook req; 3692 DoneList donelist; 3693 3694 symlook_init(&req, name); 3695 req.lockstate = lockstate; 3696 donelist_init(&donelist); 3697 if (symlook_global(&req, &donelist) != 0) 3698 return (NULL); 3699 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 3700 return ((const void **)make_function_pointer(req.sym_out, 3701 req.defobj_out)); 3702 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 3703 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 3704 else 3705 return ((const void **)(req.defobj_out->relocbase + 3706 req.sym_out->st_value)); 3707 } 3708 3709 /* 3710 * Set a pointer variable in the main program to the given value. This 3711 * is used to set key variables such as "environ" before any of the 3712 * init functions are called. 3713 */ 3714 static void 3715 set_program_var(const char *name, const void *value) 3716 { 3717 const void **addr; 3718 3719 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 3720 dbg("\"%s\": *%p <-- %p", name, addr, value); 3721 *addr = value; 3722 } 3723 } 3724 3725 /* 3726 * Search the global objects, including dependencies and main object, 3727 * for the given symbol. 3728 */ 3729 static int 3730 symlook_global(SymLook *req, DoneList *donelist) 3731 { 3732 SymLook req1; 3733 const Objlist_Entry *elm; 3734 int res; 3735 3736 symlook_init_from_req(&req1, req); 3737 3738 /* Search all objects loaded at program start up. */ 3739 if (req->defobj_out == NULL || 3740 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3741 res = symlook_list(&req1, &list_main, donelist); 3742 if (res == 0 && (req->defobj_out == NULL || 3743 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3744 req->sym_out = req1.sym_out; 3745 req->defobj_out = req1.defobj_out; 3746 assert(req->defobj_out != NULL); 3747 } 3748 } 3749 3750 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 3751 STAILQ_FOREACH(elm, &list_global, link) { 3752 if (req->defobj_out != NULL && 3753 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3754 break; 3755 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 3756 if (res == 0 && (req->defobj_out == NULL || 3757 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3758 req->sym_out = req1.sym_out; 3759 req->defobj_out = req1.defobj_out; 3760 assert(req->defobj_out != NULL); 3761 } 3762 } 3763 3764 return (req->sym_out != NULL ? 0 : ESRCH); 3765 } 3766 3767 /* 3768 * Given a symbol name in a referencing object, find the corresponding 3769 * definition of the symbol. Returns a pointer to the symbol, or NULL if 3770 * no definition was found. Returns a pointer to the Obj_Entry of the 3771 * defining object via the reference parameter DEFOBJ_OUT. 3772 */ 3773 static int 3774 symlook_default(SymLook *req, const Obj_Entry *refobj) 3775 { 3776 DoneList donelist; 3777 const Objlist_Entry *elm; 3778 SymLook req1; 3779 int res; 3780 3781 donelist_init(&donelist); 3782 symlook_init_from_req(&req1, req); 3783 3784 /* Look first in the referencing object if linked symbolically. */ 3785 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 3786 res = symlook_obj(&req1, refobj); 3787 if (res == 0) { 3788 req->sym_out = req1.sym_out; 3789 req->defobj_out = req1.defobj_out; 3790 assert(req->defobj_out != NULL); 3791 } 3792 } 3793 3794 symlook_global(req, &donelist); 3795 3796 /* Search all dlopened DAGs containing the referencing object. */ 3797 STAILQ_FOREACH(elm, &refobj->dldags, link) { 3798 if (req->sym_out != NULL && 3799 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3800 break; 3801 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 3802 if (res == 0 && (req->sym_out == NULL || 3803 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3804 req->sym_out = req1.sym_out; 3805 req->defobj_out = req1.defobj_out; 3806 assert(req->defobj_out != NULL); 3807 } 3808 } 3809 3810 /* 3811 * Search the dynamic linker itself, and possibly resolve the 3812 * symbol from there. This is how the application links to 3813 * dynamic linker services such as dlopen. 3814 */ 3815 if (req->sym_out == NULL || 3816 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3817 res = symlook_obj(&req1, &obj_rtld); 3818 if (res == 0) { 3819 req->sym_out = req1.sym_out; 3820 req->defobj_out = req1.defobj_out; 3821 assert(req->defobj_out != NULL); 3822 } 3823 } 3824 3825 return (req->sym_out != NULL ? 0 : ESRCH); 3826 } 3827 3828 static int 3829 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 3830 { 3831 const Elf_Sym *def; 3832 const Obj_Entry *defobj; 3833 const Objlist_Entry *elm; 3834 SymLook req1; 3835 int res; 3836 3837 def = NULL; 3838 defobj = NULL; 3839 STAILQ_FOREACH(elm, objlist, link) { 3840 if (donelist_check(dlp, elm->obj)) 3841 continue; 3842 symlook_init_from_req(&req1, req); 3843 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 3844 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3845 def = req1.sym_out; 3846 defobj = req1.defobj_out; 3847 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3848 break; 3849 } 3850 } 3851 } 3852 if (def != NULL) { 3853 req->sym_out = def; 3854 req->defobj_out = defobj; 3855 return (0); 3856 } 3857 return (ESRCH); 3858 } 3859 3860 /* 3861 * Search the chain of DAGS cointed to by the given Needed_Entry 3862 * for a symbol of the given name. Each DAG is scanned completely 3863 * before advancing to the next one. Returns a pointer to the symbol, 3864 * or NULL if no definition was found. 3865 */ 3866 static int 3867 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 3868 { 3869 const Elf_Sym *def; 3870 const Needed_Entry *n; 3871 const Obj_Entry *defobj; 3872 SymLook req1; 3873 int res; 3874 3875 def = NULL; 3876 defobj = NULL; 3877 symlook_init_from_req(&req1, req); 3878 for (n = needed; n != NULL; n = n->next) { 3879 if (n->obj == NULL || 3880 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 3881 continue; 3882 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3883 def = req1.sym_out; 3884 defobj = req1.defobj_out; 3885 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3886 break; 3887 } 3888 } 3889 if (def != NULL) { 3890 req->sym_out = def; 3891 req->defobj_out = defobj; 3892 return (0); 3893 } 3894 return (ESRCH); 3895 } 3896 3897 /* 3898 * Search the symbol table of a single shared object for a symbol of 3899 * the given name and version, if requested. Returns a pointer to the 3900 * symbol, or NULL if no definition was found. If the object is 3901 * filter, return filtered symbol from filtee. 3902 * 3903 * The symbol's hash value is passed in for efficiency reasons; that 3904 * eliminates many recomputations of the hash value. 3905 */ 3906 int 3907 symlook_obj(SymLook *req, const Obj_Entry *obj) 3908 { 3909 DoneList donelist; 3910 SymLook req1; 3911 int flags, res, mres; 3912 3913 /* 3914 * If there is at least one valid hash at this point, we prefer to 3915 * use the faster GNU version if available. 3916 */ 3917 if (obj->valid_hash_gnu) 3918 mres = symlook_obj1_gnu(req, obj); 3919 else if (obj->valid_hash_sysv) 3920 mres = symlook_obj1_sysv(req, obj); 3921 else 3922 return (EINVAL); 3923 3924 if (mres == 0) { 3925 if (obj->needed_filtees != NULL) { 3926 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3927 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3928 donelist_init(&donelist); 3929 symlook_init_from_req(&req1, req); 3930 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 3931 if (res == 0) { 3932 req->sym_out = req1.sym_out; 3933 req->defobj_out = req1.defobj_out; 3934 } 3935 return (res); 3936 } 3937 if (obj->needed_aux_filtees != NULL) { 3938 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3939 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3940 donelist_init(&donelist); 3941 symlook_init_from_req(&req1, req); 3942 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 3943 if (res == 0) { 3944 req->sym_out = req1.sym_out; 3945 req->defobj_out = req1.defobj_out; 3946 return (res); 3947 } 3948 } 3949 } 3950 return (mres); 3951 } 3952 3953 /* Symbol match routine common to both hash functions */ 3954 static bool 3955 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 3956 const unsigned long symnum) 3957 { 3958 Elf_Versym verndx; 3959 const Elf_Sym *symp; 3960 const char *strp; 3961 3962 symp = obj->symtab + symnum; 3963 strp = obj->strtab + symp->st_name; 3964 3965 switch (ELF_ST_TYPE(symp->st_info)) { 3966 case STT_FUNC: 3967 case STT_NOTYPE: 3968 case STT_OBJECT: 3969 case STT_COMMON: 3970 case STT_GNU_IFUNC: 3971 if (symp->st_value == 0) 3972 return (false); 3973 /* fallthrough */ 3974 case STT_TLS: 3975 if (symp->st_shndx != SHN_UNDEF) 3976 break; 3977 #ifndef __mips__ 3978 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 3979 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 3980 break; 3981 /* fallthrough */ 3982 #endif 3983 default: 3984 return (false); 3985 } 3986 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 3987 return (false); 3988 3989 if (req->ventry == NULL) { 3990 if (obj->versyms != NULL) { 3991 verndx = VER_NDX(obj->versyms[symnum]); 3992 if (verndx > obj->vernum) { 3993 _rtld_error( 3994 "%s: symbol %s references wrong version %d", 3995 obj->path, obj->strtab + symnum, verndx); 3996 return (false); 3997 } 3998 /* 3999 * If we are not called from dlsym (i.e. this 4000 * is a normal relocation from unversioned 4001 * binary), accept the symbol immediately if 4002 * it happens to have first version after this 4003 * shared object became versioned. Otherwise, 4004 * if symbol is versioned and not hidden, 4005 * remember it. If it is the only symbol with 4006 * this name exported by the shared object, it 4007 * will be returned as a match by the calling 4008 * function. If symbol is global (verndx < 2) 4009 * accept it unconditionally. 4010 */ 4011 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4012 verndx == VER_NDX_GIVEN) { 4013 result->sym_out = symp; 4014 return (true); 4015 } 4016 else if (verndx >= VER_NDX_GIVEN) { 4017 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4018 == 0) { 4019 if (result->vsymp == NULL) 4020 result->vsymp = symp; 4021 result->vcount++; 4022 } 4023 return (false); 4024 } 4025 } 4026 result->sym_out = symp; 4027 return (true); 4028 } 4029 if (obj->versyms == NULL) { 4030 if (object_match_name(obj, req->ventry->name)) { 4031 _rtld_error("%s: object %s should provide version %s " 4032 "for symbol %s", obj_rtld.path, obj->path, 4033 req->ventry->name, obj->strtab + symnum); 4034 return (false); 4035 } 4036 } else { 4037 verndx = VER_NDX(obj->versyms[symnum]); 4038 if (verndx > obj->vernum) { 4039 _rtld_error("%s: symbol %s references wrong version %d", 4040 obj->path, obj->strtab + symnum, verndx); 4041 return (false); 4042 } 4043 if (obj->vertab[verndx].hash != req->ventry->hash || 4044 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4045 /* 4046 * Version does not match. Look if this is a 4047 * global symbol and if it is not hidden. If 4048 * global symbol (verndx < 2) is available, 4049 * use it. Do not return symbol if we are 4050 * called by dlvsym, because dlvsym looks for 4051 * a specific version and default one is not 4052 * what dlvsym wants. 4053 */ 4054 if ((req->flags & SYMLOOK_DLSYM) || 4055 (verndx >= VER_NDX_GIVEN) || 4056 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4057 return (false); 4058 } 4059 } 4060 result->sym_out = symp; 4061 return (true); 4062 } 4063 4064 /* 4065 * Search for symbol using SysV hash function. 4066 * obj->buckets is known not to be NULL at this point; the test for this was 4067 * performed with the obj->valid_hash_sysv assignment. 4068 */ 4069 static int 4070 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4071 { 4072 unsigned long symnum; 4073 Sym_Match_Result matchres; 4074 4075 matchres.sym_out = NULL; 4076 matchres.vsymp = NULL; 4077 matchres.vcount = 0; 4078 4079 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4080 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4081 if (symnum >= obj->nchains) 4082 return (ESRCH); /* Bad object */ 4083 4084 if (matched_symbol(req, obj, &matchres, symnum)) { 4085 req->sym_out = matchres.sym_out; 4086 req->defobj_out = obj; 4087 return (0); 4088 } 4089 } 4090 if (matchres.vcount == 1) { 4091 req->sym_out = matchres.vsymp; 4092 req->defobj_out = obj; 4093 return (0); 4094 } 4095 return (ESRCH); 4096 } 4097 4098 /* Search for symbol using GNU hash function */ 4099 static int 4100 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4101 { 4102 Elf_Addr bloom_word; 4103 const Elf32_Word *hashval; 4104 Elf32_Word bucket; 4105 Sym_Match_Result matchres; 4106 unsigned int h1, h2; 4107 unsigned long symnum; 4108 4109 matchres.sym_out = NULL; 4110 matchres.vsymp = NULL; 4111 matchres.vcount = 0; 4112 4113 /* Pick right bitmask word from Bloom filter array */ 4114 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4115 obj->maskwords_bm_gnu]; 4116 4117 /* Calculate modulus word size of gnu hash and its derivative */ 4118 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4119 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4120 4121 /* Filter out the "definitely not in set" queries */ 4122 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4123 return (ESRCH); 4124 4125 /* Locate hash chain and corresponding value element*/ 4126 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4127 if (bucket == 0) 4128 return (ESRCH); 4129 hashval = &obj->chain_zero_gnu[bucket]; 4130 do { 4131 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4132 symnum = hashval - obj->chain_zero_gnu; 4133 if (matched_symbol(req, obj, &matchres, symnum)) { 4134 req->sym_out = matchres.sym_out; 4135 req->defobj_out = obj; 4136 return (0); 4137 } 4138 } 4139 } while ((*hashval++ & 1) == 0); 4140 if (matchres.vcount == 1) { 4141 req->sym_out = matchres.vsymp; 4142 req->defobj_out = obj; 4143 return (0); 4144 } 4145 return (ESRCH); 4146 } 4147 4148 static void 4149 trace_loaded_objects(Obj_Entry *obj) 4150 { 4151 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4152 int c; 4153 4154 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 4155 main_local = ""; 4156 4157 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL) 4158 fmt1 = "\t%o => %p (%x)\n"; 4159 4160 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL) 4161 fmt2 = "\t%o (%x)\n"; 4162 4163 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL"); 4164 4165 for (; obj; obj = obj->next) { 4166 Needed_Entry *needed; 4167 char *name, *path; 4168 bool is_lib; 4169 4170 if (list_containers && obj->needed != NULL) 4171 rtld_printf("%s:\n", obj->path); 4172 for (needed = obj->needed; needed; needed = needed->next) { 4173 if (needed->obj != NULL) { 4174 if (needed->obj->traced && !list_containers) 4175 continue; 4176 needed->obj->traced = true; 4177 path = needed->obj->path; 4178 } else 4179 path = "not found"; 4180 4181 name = (char *)obj->strtab + needed->name; 4182 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4183 4184 fmt = is_lib ? fmt1 : fmt2; 4185 while ((c = *fmt++) != '\0') { 4186 switch (c) { 4187 default: 4188 rtld_putchar(c); 4189 continue; 4190 case '\\': 4191 switch (c = *fmt) { 4192 case '\0': 4193 continue; 4194 case 'n': 4195 rtld_putchar('\n'); 4196 break; 4197 case 't': 4198 rtld_putchar('\t'); 4199 break; 4200 } 4201 break; 4202 case '%': 4203 switch (c = *fmt) { 4204 case '\0': 4205 continue; 4206 case '%': 4207 default: 4208 rtld_putchar(c); 4209 break; 4210 case 'A': 4211 rtld_putstr(main_local); 4212 break; 4213 case 'a': 4214 rtld_putstr(obj_main->path); 4215 break; 4216 case 'o': 4217 rtld_putstr(name); 4218 break; 4219 #if 0 4220 case 'm': 4221 rtld_printf("%d", sodp->sod_major); 4222 break; 4223 case 'n': 4224 rtld_printf("%d", sodp->sod_minor); 4225 break; 4226 #endif 4227 case 'p': 4228 rtld_putstr(path); 4229 break; 4230 case 'x': 4231 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4232 0); 4233 break; 4234 } 4235 break; 4236 } 4237 ++fmt; 4238 } 4239 } 4240 } 4241 } 4242 4243 /* 4244 * Unload a dlopened object and its dependencies from memory and from 4245 * our data structures. It is assumed that the DAG rooted in the 4246 * object has already been unreferenced, and that the object has a 4247 * reference count of 0. 4248 */ 4249 static void 4250 unload_object(Obj_Entry *root) 4251 { 4252 Obj_Entry *obj; 4253 Obj_Entry **linkp; 4254 4255 assert(root->refcount == 0); 4256 4257 /* 4258 * Pass over the DAG removing unreferenced objects from 4259 * appropriate lists. 4260 */ 4261 unlink_object(root); 4262 4263 /* Unmap all objects that are no longer referenced. */ 4264 linkp = &obj_list->next; 4265 while ((obj = *linkp) != NULL) { 4266 if (obj->refcount == 0) { 4267 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 4268 obj->path); 4269 dbg("unloading \"%s\"", obj->path); 4270 unload_filtees(root); 4271 munmap(obj->mapbase, obj->mapsize); 4272 linkmap_delete(obj); 4273 *linkp = obj->next; 4274 obj_count--; 4275 obj_free(obj); 4276 } else 4277 linkp = &obj->next; 4278 } 4279 obj_tail = linkp; 4280 } 4281 4282 static void 4283 unlink_object(Obj_Entry *root) 4284 { 4285 Objlist_Entry *elm; 4286 4287 if (root->refcount == 0) { 4288 /* Remove the object from the RTLD_GLOBAL list. */ 4289 objlist_remove(&list_global, root); 4290 4291 /* Remove the object from all objects' DAG lists. */ 4292 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4293 objlist_remove(&elm->obj->dldags, root); 4294 if (elm->obj != root) 4295 unlink_object(elm->obj); 4296 } 4297 } 4298 } 4299 4300 static void 4301 ref_dag(Obj_Entry *root) 4302 { 4303 Objlist_Entry *elm; 4304 4305 assert(root->dag_inited); 4306 STAILQ_FOREACH(elm, &root->dagmembers, link) 4307 elm->obj->refcount++; 4308 } 4309 4310 static void 4311 unref_dag(Obj_Entry *root) 4312 { 4313 Objlist_Entry *elm; 4314 4315 assert(root->dag_inited); 4316 STAILQ_FOREACH(elm, &root->dagmembers, link) 4317 elm->obj->refcount--; 4318 } 4319 4320 /* 4321 * Common code for MD __tls_get_addr(). 4322 */ 4323 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4324 static void * 4325 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4326 { 4327 Elf_Addr *newdtv, *dtv; 4328 RtldLockState lockstate; 4329 int to_copy; 4330 4331 dtv = *dtvp; 4332 /* Check dtv generation in case new modules have arrived */ 4333 if (dtv[0] != tls_dtv_generation) { 4334 wlock_acquire(rtld_bind_lock, &lockstate); 4335 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4336 to_copy = dtv[1]; 4337 if (to_copy > tls_max_index) 4338 to_copy = tls_max_index; 4339 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4340 newdtv[0] = tls_dtv_generation; 4341 newdtv[1] = tls_max_index; 4342 free(dtv); 4343 lock_release(rtld_bind_lock, &lockstate); 4344 dtv = *dtvp = newdtv; 4345 } 4346 4347 /* Dynamically allocate module TLS if necessary */ 4348 if (dtv[index + 1] == 0) { 4349 /* Signal safe, wlock will block out signals. */ 4350 wlock_acquire(rtld_bind_lock, &lockstate); 4351 if (!dtv[index + 1]) 4352 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4353 lock_release(rtld_bind_lock, &lockstate); 4354 } 4355 return ((void *)(dtv[index + 1] + offset)); 4356 } 4357 4358 void * 4359 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4360 { 4361 Elf_Addr *dtv; 4362 4363 dtv = *dtvp; 4364 /* Check dtv generation in case new modules have arrived */ 4365 if (__predict_true(dtv[0] == tls_dtv_generation && 4366 dtv[index + 1] != 0)) 4367 return ((void *)(dtv[index + 1] + offset)); 4368 return (tls_get_addr_slow(dtvp, index, offset)); 4369 } 4370 4371 #if defined(__arm__) || defined(__mips__) || defined(__powerpc__) 4372 4373 /* 4374 * Allocate Static TLS using the Variant I method. 4375 */ 4376 void * 4377 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4378 { 4379 Obj_Entry *obj; 4380 char *tcb; 4381 Elf_Addr **tls; 4382 Elf_Addr *dtv; 4383 Elf_Addr addr; 4384 int i; 4385 4386 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4387 return (oldtcb); 4388 4389 assert(tcbsize >= TLS_TCB_SIZE); 4390 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 4391 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 4392 4393 if (oldtcb != NULL) { 4394 memcpy(tls, oldtcb, tls_static_space); 4395 free(oldtcb); 4396 4397 /* Adjust the DTV. */ 4398 dtv = tls[0]; 4399 for (i = 0; i < dtv[1]; i++) { 4400 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4401 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4402 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 4403 } 4404 } 4405 } else { 4406 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4407 tls[0] = dtv; 4408 dtv[0] = tls_dtv_generation; 4409 dtv[1] = tls_max_index; 4410 4411 for (obj = objs; obj; obj = obj->next) { 4412 if (obj->tlsoffset > 0) { 4413 addr = (Elf_Addr)tls + obj->tlsoffset; 4414 if (obj->tlsinitsize > 0) 4415 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4416 if (obj->tlssize > obj->tlsinitsize) 4417 memset((void*) (addr + obj->tlsinitsize), 0, 4418 obj->tlssize - obj->tlsinitsize); 4419 dtv[obj->tlsindex + 1] = addr; 4420 } 4421 } 4422 } 4423 4424 return (tcb); 4425 } 4426 4427 void 4428 free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4429 { 4430 Elf_Addr *dtv; 4431 Elf_Addr tlsstart, tlsend; 4432 int dtvsize, i; 4433 4434 assert(tcbsize >= TLS_TCB_SIZE); 4435 4436 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 4437 tlsend = tlsstart + tls_static_space; 4438 4439 dtv = *(Elf_Addr **)tlsstart; 4440 dtvsize = dtv[1]; 4441 for (i = 0; i < dtvsize; i++) { 4442 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4443 free((void*)dtv[i+2]); 4444 } 4445 } 4446 free(dtv); 4447 free(tcb); 4448 } 4449 4450 #endif 4451 4452 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 4453 4454 /* 4455 * Allocate Static TLS using the Variant II method. 4456 */ 4457 void * 4458 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4459 { 4460 Obj_Entry *obj; 4461 size_t size, ralign; 4462 char *tls; 4463 Elf_Addr *dtv, *olddtv; 4464 Elf_Addr segbase, oldsegbase, addr; 4465 int i; 4466 4467 ralign = tcbalign; 4468 if (tls_static_max_align > ralign) 4469 ralign = tls_static_max_align; 4470 size = round(tls_static_space, ralign) + round(tcbsize, ralign); 4471 4472 assert(tcbsize >= 2*sizeof(Elf_Addr)); 4473 tls = malloc_aligned(size, ralign); 4474 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4475 4476 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign)); 4477 ((Elf_Addr*)segbase)[0] = segbase; 4478 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 4479 4480 dtv[0] = tls_dtv_generation; 4481 dtv[1] = tls_max_index; 4482 4483 if (oldtls) { 4484 /* 4485 * Copy the static TLS block over whole. 4486 */ 4487 oldsegbase = (Elf_Addr) oldtls; 4488 memcpy((void *)(segbase - tls_static_space), 4489 (const void *)(oldsegbase - tls_static_space), 4490 tls_static_space); 4491 4492 /* 4493 * If any dynamic TLS blocks have been created tls_get_addr(), 4494 * move them over. 4495 */ 4496 olddtv = ((Elf_Addr**)oldsegbase)[1]; 4497 for (i = 0; i < olddtv[1]; i++) { 4498 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 4499 dtv[i+2] = olddtv[i+2]; 4500 olddtv[i+2] = 0; 4501 } 4502 } 4503 4504 /* 4505 * We assume that this block was the one we created with 4506 * allocate_initial_tls(). 4507 */ 4508 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 4509 } else { 4510 for (obj = objs; obj; obj = obj->next) { 4511 if (obj->tlsoffset) { 4512 addr = segbase - obj->tlsoffset; 4513 memset((void*) (addr + obj->tlsinitsize), 4514 0, obj->tlssize - obj->tlsinitsize); 4515 if (obj->tlsinit) 4516 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4517 dtv[obj->tlsindex + 1] = addr; 4518 } 4519 } 4520 } 4521 4522 return (void*) segbase; 4523 } 4524 4525 void 4526 free_tls(void *tls, size_t tcbsize, size_t tcbalign) 4527 { 4528 Elf_Addr* dtv; 4529 size_t size, ralign; 4530 int dtvsize, i; 4531 Elf_Addr tlsstart, tlsend; 4532 4533 /* 4534 * Figure out the size of the initial TLS block so that we can 4535 * find stuff which ___tls_get_addr() allocated dynamically. 4536 */ 4537 ralign = tcbalign; 4538 if (tls_static_max_align > ralign) 4539 ralign = tls_static_max_align; 4540 size = round(tls_static_space, ralign); 4541 4542 dtv = ((Elf_Addr**)tls)[1]; 4543 dtvsize = dtv[1]; 4544 tlsend = (Elf_Addr) tls; 4545 tlsstart = tlsend - size; 4546 for (i = 0; i < dtvsize; i++) { 4547 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 4548 free_aligned((void *)dtv[i + 2]); 4549 } 4550 } 4551 4552 free_aligned((void *)tlsstart); 4553 free((void*) dtv); 4554 } 4555 4556 #endif 4557 4558 /* 4559 * Allocate TLS block for module with given index. 4560 */ 4561 void * 4562 allocate_module_tls(int index) 4563 { 4564 Obj_Entry* obj; 4565 char* p; 4566 4567 for (obj = obj_list; obj; obj = obj->next) { 4568 if (obj->tlsindex == index) 4569 break; 4570 } 4571 if (!obj) { 4572 _rtld_error("Can't find module with TLS index %d", index); 4573 die(); 4574 } 4575 4576 p = malloc_aligned(obj->tlssize, obj->tlsalign); 4577 memcpy(p, obj->tlsinit, obj->tlsinitsize); 4578 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 4579 4580 return p; 4581 } 4582 4583 bool 4584 allocate_tls_offset(Obj_Entry *obj) 4585 { 4586 size_t off; 4587 4588 if (obj->tls_done) 4589 return true; 4590 4591 if (obj->tlssize == 0) { 4592 obj->tls_done = true; 4593 return true; 4594 } 4595 4596 if (obj->tlsindex == 1) 4597 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 4598 else 4599 off = calculate_tls_offset(tls_last_offset, tls_last_size, 4600 obj->tlssize, obj->tlsalign); 4601 4602 /* 4603 * If we have already fixed the size of the static TLS block, we 4604 * must stay within that size. When allocating the static TLS, we 4605 * leave a small amount of space spare to be used for dynamically 4606 * loading modules which use static TLS. 4607 */ 4608 if (tls_static_space != 0) { 4609 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 4610 return false; 4611 } else if (obj->tlsalign > tls_static_max_align) { 4612 tls_static_max_align = obj->tlsalign; 4613 } 4614 4615 tls_last_offset = obj->tlsoffset = off; 4616 tls_last_size = obj->tlssize; 4617 obj->tls_done = true; 4618 4619 return true; 4620 } 4621 4622 void 4623 free_tls_offset(Obj_Entry *obj) 4624 { 4625 4626 /* 4627 * If we were the last thing to allocate out of the static TLS 4628 * block, we give our space back to the 'allocator'. This is a 4629 * simplistic workaround to allow libGL.so.1 to be loaded and 4630 * unloaded multiple times. 4631 */ 4632 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 4633 == calculate_tls_end(tls_last_offset, tls_last_size)) { 4634 tls_last_offset -= obj->tlssize; 4635 tls_last_size = 0; 4636 } 4637 } 4638 4639 void * 4640 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 4641 { 4642 void *ret; 4643 RtldLockState lockstate; 4644 4645 wlock_acquire(rtld_bind_lock, &lockstate); 4646 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign); 4647 lock_release(rtld_bind_lock, &lockstate); 4648 return (ret); 4649 } 4650 4651 void 4652 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4653 { 4654 RtldLockState lockstate; 4655 4656 wlock_acquire(rtld_bind_lock, &lockstate); 4657 free_tls(tcb, tcbsize, tcbalign); 4658 lock_release(rtld_bind_lock, &lockstate); 4659 } 4660 4661 static void 4662 object_add_name(Obj_Entry *obj, const char *name) 4663 { 4664 Name_Entry *entry; 4665 size_t len; 4666 4667 len = strlen(name); 4668 entry = malloc(sizeof(Name_Entry) + len); 4669 4670 if (entry != NULL) { 4671 strcpy(entry->name, name); 4672 STAILQ_INSERT_TAIL(&obj->names, entry, link); 4673 } 4674 } 4675 4676 static int 4677 object_match_name(const Obj_Entry *obj, const char *name) 4678 { 4679 Name_Entry *entry; 4680 4681 STAILQ_FOREACH(entry, &obj->names, link) { 4682 if (strcmp(name, entry->name) == 0) 4683 return (1); 4684 } 4685 return (0); 4686 } 4687 4688 static Obj_Entry * 4689 locate_dependency(const Obj_Entry *obj, const char *name) 4690 { 4691 const Objlist_Entry *entry; 4692 const Needed_Entry *needed; 4693 4694 STAILQ_FOREACH(entry, &list_main, link) { 4695 if (object_match_name(entry->obj, name)) 4696 return entry->obj; 4697 } 4698 4699 for (needed = obj->needed; needed != NULL; needed = needed->next) { 4700 if (strcmp(obj->strtab + needed->name, name) == 0 || 4701 (needed->obj != NULL && object_match_name(needed->obj, name))) { 4702 /* 4703 * If there is DT_NEEDED for the name we are looking for, 4704 * we are all set. Note that object might not be found if 4705 * dependency was not loaded yet, so the function can 4706 * return NULL here. This is expected and handled 4707 * properly by the caller. 4708 */ 4709 return (needed->obj); 4710 } 4711 } 4712 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 4713 obj->path, name); 4714 die(); 4715 } 4716 4717 static int 4718 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 4719 const Elf_Vernaux *vna) 4720 { 4721 const Elf_Verdef *vd; 4722 const char *vername; 4723 4724 vername = refobj->strtab + vna->vna_name; 4725 vd = depobj->verdef; 4726 if (vd == NULL) { 4727 _rtld_error("%s: version %s required by %s not defined", 4728 depobj->path, vername, refobj->path); 4729 return (-1); 4730 } 4731 for (;;) { 4732 if (vd->vd_version != VER_DEF_CURRENT) { 4733 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4734 depobj->path, vd->vd_version); 4735 return (-1); 4736 } 4737 if (vna->vna_hash == vd->vd_hash) { 4738 const Elf_Verdaux *aux = (const Elf_Verdaux *) 4739 ((char *)vd + vd->vd_aux); 4740 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 4741 return (0); 4742 } 4743 if (vd->vd_next == 0) 4744 break; 4745 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4746 } 4747 if (vna->vna_flags & VER_FLG_WEAK) 4748 return (0); 4749 _rtld_error("%s: version %s required by %s not found", 4750 depobj->path, vername, refobj->path); 4751 return (-1); 4752 } 4753 4754 static int 4755 rtld_verify_object_versions(Obj_Entry *obj) 4756 { 4757 const Elf_Verneed *vn; 4758 const Elf_Verdef *vd; 4759 const Elf_Verdaux *vda; 4760 const Elf_Vernaux *vna; 4761 const Obj_Entry *depobj; 4762 int maxvernum, vernum; 4763 4764 if (obj->ver_checked) 4765 return (0); 4766 obj->ver_checked = true; 4767 4768 maxvernum = 0; 4769 /* 4770 * Walk over defined and required version records and figure out 4771 * max index used by any of them. Do very basic sanity checking 4772 * while there. 4773 */ 4774 vn = obj->verneed; 4775 while (vn != NULL) { 4776 if (vn->vn_version != VER_NEED_CURRENT) { 4777 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 4778 obj->path, vn->vn_version); 4779 return (-1); 4780 } 4781 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4782 for (;;) { 4783 vernum = VER_NEED_IDX(vna->vna_other); 4784 if (vernum > maxvernum) 4785 maxvernum = vernum; 4786 if (vna->vna_next == 0) 4787 break; 4788 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4789 } 4790 if (vn->vn_next == 0) 4791 break; 4792 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4793 } 4794 4795 vd = obj->verdef; 4796 while (vd != NULL) { 4797 if (vd->vd_version != VER_DEF_CURRENT) { 4798 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4799 obj->path, vd->vd_version); 4800 return (-1); 4801 } 4802 vernum = VER_DEF_IDX(vd->vd_ndx); 4803 if (vernum > maxvernum) 4804 maxvernum = vernum; 4805 if (vd->vd_next == 0) 4806 break; 4807 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4808 } 4809 4810 if (maxvernum == 0) 4811 return (0); 4812 4813 /* 4814 * Store version information in array indexable by version index. 4815 * Verify that object version requirements are satisfied along the 4816 * way. 4817 */ 4818 obj->vernum = maxvernum + 1; 4819 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 4820 4821 vd = obj->verdef; 4822 while (vd != NULL) { 4823 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 4824 vernum = VER_DEF_IDX(vd->vd_ndx); 4825 assert(vernum <= maxvernum); 4826 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 4827 obj->vertab[vernum].hash = vd->vd_hash; 4828 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 4829 obj->vertab[vernum].file = NULL; 4830 obj->vertab[vernum].flags = 0; 4831 } 4832 if (vd->vd_next == 0) 4833 break; 4834 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4835 } 4836 4837 vn = obj->verneed; 4838 while (vn != NULL) { 4839 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 4840 if (depobj == NULL) 4841 return (-1); 4842 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4843 for (;;) { 4844 if (check_object_provided_version(obj, depobj, vna)) 4845 return (-1); 4846 vernum = VER_NEED_IDX(vna->vna_other); 4847 assert(vernum <= maxvernum); 4848 obj->vertab[vernum].hash = vna->vna_hash; 4849 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 4850 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 4851 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 4852 VER_INFO_HIDDEN : 0; 4853 if (vna->vna_next == 0) 4854 break; 4855 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4856 } 4857 if (vn->vn_next == 0) 4858 break; 4859 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4860 } 4861 return 0; 4862 } 4863 4864 static int 4865 rtld_verify_versions(const Objlist *objlist) 4866 { 4867 Objlist_Entry *entry; 4868 int rc; 4869 4870 rc = 0; 4871 STAILQ_FOREACH(entry, objlist, link) { 4872 /* 4873 * Skip dummy objects or objects that have their version requirements 4874 * already checked. 4875 */ 4876 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 4877 continue; 4878 if (rtld_verify_object_versions(entry->obj) == -1) { 4879 rc = -1; 4880 if (ld_tracing == NULL) 4881 break; 4882 } 4883 } 4884 if (rc == 0 || ld_tracing != NULL) 4885 rc = rtld_verify_object_versions(&obj_rtld); 4886 return rc; 4887 } 4888 4889 const Ver_Entry * 4890 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 4891 { 4892 Elf_Versym vernum; 4893 4894 if (obj->vertab) { 4895 vernum = VER_NDX(obj->versyms[symnum]); 4896 if (vernum >= obj->vernum) { 4897 _rtld_error("%s: symbol %s has wrong verneed value %d", 4898 obj->path, obj->strtab + symnum, vernum); 4899 } else if (obj->vertab[vernum].hash != 0) { 4900 return &obj->vertab[vernum]; 4901 } 4902 } 4903 return NULL; 4904 } 4905 4906 int 4907 _rtld_get_stack_prot(void) 4908 { 4909 4910 return (stack_prot); 4911 } 4912 4913 int 4914 _rtld_is_dlopened(void *arg) 4915 { 4916 Obj_Entry *obj; 4917 RtldLockState lockstate; 4918 int res; 4919 4920 rlock_acquire(rtld_bind_lock, &lockstate); 4921 obj = dlcheck(arg); 4922 if (obj == NULL) 4923 obj = obj_from_addr(arg); 4924 if (obj == NULL) { 4925 _rtld_error("No shared object contains address"); 4926 lock_release(rtld_bind_lock, &lockstate); 4927 return (-1); 4928 } 4929 res = obj->dlopened ? 1 : 0; 4930 lock_release(rtld_bind_lock, &lockstate); 4931 return (res); 4932 } 4933 4934 static void 4935 map_stacks_exec(RtldLockState *lockstate) 4936 { 4937 void (*thr_map_stacks_exec)(void); 4938 4939 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 4940 return; 4941 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 4942 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 4943 if (thr_map_stacks_exec != NULL) { 4944 stack_prot |= PROT_EXEC; 4945 thr_map_stacks_exec(); 4946 } 4947 } 4948 4949 void 4950 symlook_init(SymLook *dst, const char *name) 4951 { 4952 4953 bzero(dst, sizeof(*dst)); 4954 dst->name = name; 4955 dst->hash = elf_hash(name); 4956 dst->hash_gnu = gnu_hash(name); 4957 } 4958 4959 static void 4960 symlook_init_from_req(SymLook *dst, const SymLook *src) 4961 { 4962 4963 dst->name = src->name; 4964 dst->hash = src->hash; 4965 dst->hash_gnu = src->hash_gnu; 4966 dst->ventry = src->ventry; 4967 dst->flags = src->flags; 4968 dst->defobj_out = NULL; 4969 dst->sym_out = NULL; 4970 dst->lockstate = src->lockstate; 4971 } 4972 4973 4974 /* 4975 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 4976 */ 4977 static int 4978 parse_libdir(const char *str) 4979 { 4980 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 4981 const char *orig; 4982 int fd; 4983 char c; 4984 4985 orig = str; 4986 fd = 0; 4987 for (c = *str; c != '\0'; c = *++str) { 4988 if (c < '0' || c > '9') 4989 return (-1); 4990 4991 fd *= RADIX; 4992 fd += c - '0'; 4993 } 4994 4995 /* Make sure we actually parsed something. */ 4996 if (str == orig) { 4997 _rtld_error("failed to parse directory FD from '%s'", str); 4998 return (-1); 4999 } 5000 return (fd); 5001 } 5002 5003 /* 5004 * Overrides for libc_pic-provided functions. 5005 */ 5006 5007 int 5008 __getosreldate(void) 5009 { 5010 size_t len; 5011 int oid[2]; 5012 int error, osrel; 5013 5014 if (osreldate != 0) 5015 return (osreldate); 5016 5017 oid[0] = CTL_KERN; 5018 oid[1] = KERN_OSRELDATE; 5019 osrel = 0; 5020 len = sizeof(osrel); 5021 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 5022 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 5023 osreldate = osrel; 5024 return (osreldate); 5025 } 5026 5027 void 5028 exit(int status) 5029 { 5030 5031 _exit(status); 5032 } 5033 5034 void (*__cleanup)(void); 5035 int __isthreaded = 0; 5036 int _thread_autoinit_dummy_decl = 1; 5037 5038 /* 5039 * No unresolved symbols for rtld. 5040 */ 5041 void 5042 __pthread_cxa_finalize(struct dl_phdr_info *a) 5043 { 5044 } 5045 5046 void 5047 __stack_chk_fail(void) 5048 { 5049 5050 _rtld_error("stack overflow detected; terminated"); 5051 die(); 5052 } 5053 __weak_reference(__stack_chk_fail, __stack_chk_fail_local); 5054 5055 void 5056 __chk_fail(void) 5057 { 5058 5059 _rtld_error("buffer overflow detected; terminated"); 5060 die(); 5061 } 5062 5063 const char * 5064 rtld_strerror(int errnum) 5065 { 5066 5067 if (errnum < 0 || errnum >= sys_nerr) 5068 return ("Unknown error"); 5069 return (sys_errlist[errnum]); 5070 } 5071