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 digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 82 const Elf_Dyn **, const Elf_Dyn **); 83 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *, 84 const Elf_Dyn *); 85 static void digest_dynamic(Obj_Entry *, int); 86 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 87 static Obj_Entry *dlcheck(void *); 88 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, 89 int lo_flags, int mode, RtldLockState *lockstate); 90 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 91 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 92 static bool donelist_check(DoneList *, const Obj_Entry *); 93 static void errmsg_restore(char *); 94 static char *errmsg_save(void); 95 static void *fill_search_info(const char *, size_t, void *); 96 static char *find_library(const char *, const Obj_Entry *, int *); 97 static const char *gethints(bool); 98 static void init_dag(Obj_Entry *); 99 static void init_pagesizes(Elf_Auxinfo **aux_info); 100 static void init_rtld(caddr_t, Elf_Auxinfo **); 101 static void initlist_add_neededs(Needed_Entry *, Objlist *); 102 static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *); 103 static void linkmap_add(Obj_Entry *); 104 static void linkmap_delete(Obj_Entry *); 105 static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 106 static void unload_filtees(Obj_Entry *); 107 static int load_needed_objects(Obj_Entry *, int); 108 static int load_preload_objects(void); 109 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 110 static void map_stacks_exec(RtldLockState *); 111 static Obj_Entry *obj_from_addr(const void *); 112 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 113 static void objlist_call_init(Objlist *, RtldLockState *); 114 static void objlist_clear(Objlist *); 115 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 116 static void objlist_init(Objlist *); 117 static void objlist_push_head(Objlist *, Obj_Entry *); 118 static void objlist_push_tail(Objlist *, Obj_Entry *); 119 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 120 static void objlist_remove(Objlist *, Obj_Entry *); 121 static int parse_libdir(const char *); 122 static void *path_enumerate(const char *, path_enum_proc, void *); 123 static int relocate_object_dag(Obj_Entry *root, bool bind_now, 124 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 125 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 126 int flags, RtldLockState *lockstate); 127 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 128 RtldLockState *); 129 static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now, 130 int flags, RtldLockState *lockstate); 131 static int rtld_dirname(const char *, char *); 132 static int rtld_dirname_abs(const char *, char *); 133 static void *rtld_dlopen(const char *name, int fd, int mode); 134 static void rtld_exit(void); 135 static char *search_library_path(const char *, const char *); 136 static char *search_library_pathfds(const char *, const char *, int *); 137 static const void **get_program_var_addr(const char *, RtldLockState *); 138 static void set_program_var(const char *, const void *); 139 static int symlook_default(SymLook *, const Obj_Entry *refobj); 140 static int symlook_global(SymLook *, DoneList *); 141 static void symlook_init_from_req(SymLook *, const SymLook *); 142 static int symlook_list(SymLook *, const Objlist *, DoneList *); 143 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 144 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 145 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 146 static void trace_loaded_objects(Obj_Entry *); 147 static void unlink_object(Obj_Entry *); 148 static void unload_object(Obj_Entry *); 149 static void unref_dag(Obj_Entry *); 150 static void ref_dag(Obj_Entry *); 151 static char *origin_subst_one(char *, const char *, const char *, bool); 152 static char *origin_subst(char *, const char *); 153 static void preinit_main(void); 154 static int rtld_verify_versions(const Objlist *); 155 static int rtld_verify_object_versions(Obj_Entry *); 156 static void object_add_name(Obj_Entry *, const char *); 157 static int object_match_name(const Obj_Entry *, const char *); 158 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 159 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 160 struct dl_phdr_info *phdr_info); 161 static uint32_t gnu_hash(const char *); 162 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 163 const unsigned long); 164 165 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported; 166 void _r_debug_postinit(struct link_map *) __noinline __exported; 167 168 int __sys_openat(int, const char *, int, ...); 169 170 /* 171 * Data declarations. 172 */ 173 static char *error_message; /* Message for dlerror(), or NULL */ 174 struct r_debug r_debug __exported; /* for GDB; */ 175 static bool libmap_disable; /* Disable libmap */ 176 static bool ld_loadfltr; /* Immediate filters processing */ 177 static char *libmap_override; /* Maps to use in addition to libmap.conf */ 178 static bool trust; /* False for setuid and setgid programs */ 179 static bool dangerous_ld_env; /* True if environment variables have been 180 used to affect the libraries loaded */ 181 static char *ld_bind_now; /* Environment variable for immediate binding */ 182 static char *ld_debug; /* Environment variable for debugging */ 183 static char *ld_library_path; /* Environment variable for search path */ 184 static char *ld_library_dirs; /* Environment variable for library descriptors */ 185 static char *ld_preload; /* Environment variable for libraries to 186 load first */ 187 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 188 static char *ld_tracing; /* Called from ldd to print libs */ 189 static char *ld_utrace; /* Use utrace() to log events. */ 190 static Obj_Entry *obj_list; /* Head of linked list of shared objects */ 191 static Obj_Entry **obj_tail; /* Link field of last object in list */ 192 static Obj_Entry *obj_main; /* The main program shared object */ 193 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 194 static unsigned int obj_count; /* Number of objects in obj_list */ 195 static unsigned int obj_loads; /* Number of objects in obj_list */ 196 197 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 198 STAILQ_HEAD_INITIALIZER(list_global); 199 static Objlist list_main = /* Objects loaded at program startup */ 200 STAILQ_HEAD_INITIALIZER(list_main); 201 static Objlist list_fini = /* Objects needing fini() calls */ 202 STAILQ_HEAD_INITIALIZER(list_fini); 203 204 Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 205 206 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 207 208 extern Elf_Dyn _DYNAMIC; 209 #pragma weak _DYNAMIC 210 #ifndef RTLD_IS_DYNAMIC 211 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL) 212 #endif 213 214 int dlclose(void *) __exported; 215 char *dlerror(void) __exported; 216 void *dlopen(const char *, int) __exported; 217 void *fdlopen(int, int) __exported; 218 void *dlsym(void *, const char *) __exported; 219 dlfunc_t dlfunc(void *, const char *) __exported; 220 void *dlvsym(void *, const char *, const char *) __exported; 221 int dladdr(const void *, Dl_info *) __exported; 222 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *), 223 void (*)(void *), void (*)(void *), void (*)(void *)) __exported; 224 int dlinfo(void *, int , void *) __exported; 225 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported; 226 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported; 227 int _rtld_get_stack_prot(void) __exported; 228 int _rtld_is_dlopened(void *) __exported; 229 void _rtld_error(const char *, ...) __exported; 230 231 int npagesizes, osreldate; 232 size_t *pagesizes; 233 234 long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0}; 235 236 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 237 static int max_stack_flags; 238 239 /* 240 * Global declarations normally provided by crt1. The dynamic linker is 241 * not built with crt1, so we have to provide them ourselves. 242 */ 243 char *__progname; 244 char **environ; 245 246 /* 247 * Used to pass argc, argv to init functions. 248 */ 249 int main_argc; 250 char **main_argv; 251 252 /* 253 * Globals to control TLS allocation. 254 */ 255 size_t tls_last_offset; /* Static TLS offset of last module */ 256 size_t tls_last_size; /* Static TLS size of last module */ 257 size_t tls_static_space; /* Static TLS space allocated */ 258 size_t tls_static_max_align; 259 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 260 int tls_max_index = 1; /* Largest module index allocated */ 261 262 bool ld_library_path_rpath = false; 263 264 /* 265 * Fill in a DoneList with an allocation large enough to hold all of 266 * the currently-loaded objects. Keep this as a macro since it calls 267 * alloca and we want that to occur within the scope of the caller. 268 */ 269 #define donelist_init(dlp) \ 270 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 271 assert((dlp)->objs != NULL), \ 272 (dlp)->num_alloc = obj_count, \ 273 (dlp)->num_used = 0) 274 275 #define UTRACE_DLOPEN_START 1 276 #define UTRACE_DLOPEN_STOP 2 277 #define UTRACE_DLCLOSE_START 3 278 #define UTRACE_DLCLOSE_STOP 4 279 #define UTRACE_LOAD_OBJECT 5 280 #define UTRACE_UNLOAD_OBJECT 6 281 #define UTRACE_ADD_RUNDEP 7 282 #define UTRACE_PRELOAD_FINISHED 8 283 #define UTRACE_INIT_CALL 9 284 #define UTRACE_FINI_CALL 10 285 #define UTRACE_DLSYM_START 11 286 #define UTRACE_DLSYM_STOP 12 287 288 struct utrace_rtld { 289 char sig[4]; /* 'RTLD' */ 290 int event; 291 void *handle; 292 void *mapbase; /* Used for 'parent' and 'init/fini' */ 293 size_t mapsize; 294 int refcnt; /* Used for 'mode' */ 295 char name[MAXPATHLEN]; 296 }; 297 298 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 299 if (ld_utrace != NULL) \ 300 ld_utrace_log(e, h, mb, ms, r, n); \ 301 } while (0) 302 303 static void 304 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 305 int refcnt, const char *name) 306 { 307 struct utrace_rtld ut; 308 309 ut.sig[0] = 'R'; 310 ut.sig[1] = 'T'; 311 ut.sig[2] = 'L'; 312 ut.sig[3] = 'D'; 313 ut.event = event; 314 ut.handle = handle; 315 ut.mapbase = mapbase; 316 ut.mapsize = mapsize; 317 ut.refcnt = refcnt; 318 bzero(ut.name, sizeof(ut.name)); 319 if (name) 320 strlcpy(ut.name, name, sizeof(ut.name)); 321 utrace(&ut, sizeof(ut)); 322 } 323 324 /* 325 * Main entry point for dynamic linking. The first argument is the 326 * stack pointer. The stack is expected to be laid out as described 327 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 328 * Specifically, the stack pointer points to a word containing 329 * ARGC. Following that in the stack is a null-terminated sequence 330 * of pointers to argument strings. Then comes a null-terminated 331 * sequence of pointers to environment strings. Finally, there is a 332 * sequence of "auxiliary vector" entries. 333 * 334 * The second argument points to a place to store the dynamic linker's 335 * exit procedure pointer and the third to a place to store the main 336 * program's object. 337 * 338 * The return value is the main program's entry point. 339 */ 340 func_ptr_type 341 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 342 { 343 Elf_Auxinfo *aux_info[AT_COUNT]; 344 int i; 345 int argc; 346 char **argv; 347 char **env; 348 Elf_Auxinfo *aux; 349 Elf_Auxinfo *auxp; 350 const char *argv0; 351 Objlist_Entry *entry; 352 Obj_Entry *obj; 353 Obj_Entry **preload_tail; 354 Obj_Entry *last_interposer; 355 Objlist initlist; 356 RtldLockState lockstate; 357 char *library_path_rpath; 358 int mib[2]; 359 size_t len; 360 361 /* 362 * On entry, the dynamic linker itself has not been relocated yet. 363 * Be very careful not to reference any global data until after 364 * init_rtld has returned. It is OK to reference file-scope statics 365 * and string constants, and to call static and global functions. 366 */ 367 368 /* Find the auxiliary vector on the stack. */ 369 argc = *sp++; 370 argv = (char **) sp; 371 sp += argc + 1; /* Skip over arguments and NULL terminator */ 372 env = (char **) sp; 373 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 374 ; 375 aux = (Elf_Auxinfo *) sp; 376 377 /* Digest the auxiliary vector. */ 378 for (i = 0; i < AT_COUNT; i++) 379 aux_info[i] = NULL; 380 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 381 if (auxp->a_type < AT_COUNT) 382 aux_info[auxp->a_type] = auxp; 383 } 384 385 /* Initialize and relocate ourselves. */ 386 assert(aux_info[AT_BASE] != NULL); 387 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 388 389 __progname = obj_rtld.path; 390 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 391 environ = env; 392 main_argc = argc; 393 main_argv = argv; 394 395 if (aux_info[AT_CANARY] != NULL && 396 aux_info[AT_CANARY]->a_un.a_ptr != NULL) { 397 i = aux_info[AT_CANARYLEN]->a_un.a_val; 398 if (i > sizeof(__stack_chk_guard)) 399 i = sizeof(__stack_chk_guard); 400 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i); 401 } else { 402 mib[0] = CTL_KERN; 403 mib[1] = KERN_ARND; 404 405 len = sizeof(__stack_chk_guard); 406 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 || 407 len != sizeof(__stack_chk_guard)) { 408 /* If sysctl was unsuccessful, use the "terminator canary". */ 409 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0; 410 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0; 411 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n'; 412 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255; 413 } 414 } 415 416 trust = !issetugid(); 417 418 ld_bind_now = getenv(LD_ "BIND_NOW"); 419 /* 420 * If the process is tainted, then we un-set the dangerous environment 421 * variables. The process will be marked as tainted until setuid(2) 422 * is called. If any child process calls setuid(2) we do not want any 423 * future processes to honor the potentially un-safe variables. 424 */ 425 if (!trust) { 426 if (unsetenv(LD_ "PRELOAD") || unsetenv(LD_ "LIBMAP") || 427 unsetenv(LD_ "LIBRARY_PATH") || unsetenv(LD_ "LIBRARY_PATH_FDS") || 428 unsetenv(LD_ "LIBMAP_DISABLE") || 429 unsetenv(LD_ "DEBUG") || unsetenv(LD_ "ELF_HINTS_PATH") || 430 unsetenv(LD_ "LOADFLTR") || unsetenv(LD_ "LIBRARY_PATH_RPATH")) { 431 _rtld_error("environment corrupt; aborting"); 432 rtld_die(); 433 } 434 } 435 ld_debug = getenv(LD_ "DEBUG"); 436 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL; 437 libmap_override = getenv(LD_ "LIBMAP"); 438 ld_library_path = getenv(LD_ "LIBRARY_PATH"); 439 ld_library_dirs = getenv(LD_ "LIBRARY_PATH_FDS"); 440 ld_preload = getenv(LD_ "PRELOAD"); 441 ld_elf_hints_path = getenv(LD_ "ELF_HINTS_PATH"); 442 ld_loadfltr = getenv(LD_ "LOADFLTR") != NULL; 443 library_path_rpath = getenv(LD_ "LIBRARY_PATH_RPATH"); 444 if (library_path_rpath != NULL) { 445 if (library_path_rpath[0] == 'y' || 446 library_path_rpath[0] == 'Y' || 447 library_path_rpath[0] == '1') 448 ld_library_path_rpath = true; 449 else 450 ld_library_path_rpath = false; 451 } 452 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 453 (ld_library_path != NULL) || (ld_preload != NULL) || 454 (ld_elf_hints_path != NULL) || ld_loadfltr; 455 ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS"); 456 ld_utrace = getenv(LD_ "UTRACE"); 457 458 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 459 ld_elf_hints_path = _PATH_ELF_HINTS; 460 461 if (ld_debug != NULL && *ld_debug != '\0') 462 debug = 1; 463 dbg("%s is initialized, base address = %p", __progname, 464 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 465 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 466 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 467 468 dbg("initializing thread locks"); 469 lockdflt_init(); 470 471 /* 472 * Load the main program, or process its program header if it is 473 * already loaded. 474 */ 475 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */ 476 int fd = aux_info[AT_EXECFD]->a_un.a_val; 477 dbg("loading main program"); 478 obj_main = map_object(fd, argv0, NULL); 479 close(fd); 480 if (obj_main == NULL) 481 rtld_die(); 482 max_stack_flags = obj->stack_flags; 483 } else { /* Main program already loaded. */ 484 const Elf_Phdr *phdr; 485 int phnum; 486 caddr_t entry; 487 488 dbg("processing main program's program header"); 489 assert(aux_info[AT_PHDR] != NULL); 490 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 491 assert(aux_info[AT_PHNUM] != NULL); 492 phnum = aux_info[AT_PHNUM]->a_un.a_val; 493 assert(aux_info[AT_PHENT] != NULL); 494 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 495 assert(aux_info[AT_ENTRY] != NULL); 496 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 497 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL) 498 rtld_die(); 499 } 500 501 if (aux_info[AT_EXECPATH] != 0) { 502 char *kexecpath; 503 char buf[MAXPATHLEN]; 504 505 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 506 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 507 if (kexecpath[0] == '/') 508 obj_main->path = kexecpath; 509 else if (getcwd(buf, sizeof(buf)) == NULL || 510 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 511 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 512 obj_main->path = xstrdup(argv0); 513 else 514 obj_main->path = xstrdup(buf); 515 } else { 516 dbg("No AT_EXECPATH"); 517 obj_main->path = xstrdup(argv0); 518 } 519 dbg("obj_main path %s", obj_main->path); 520 obj_main->mainprog = true; 521 522 if (aux_info[AT_STACKPROT] != NULL && 523 aux_info[AT_STACKPROT]->a_un.a_val != 0) 524 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 525 526 #ifndef COMPAT_32BIT 527 /* 528 * Get the actual dynamic linker pathname from the executable if 529 * possible. (It should always be possible.) That ensures that 530 * gdb will find the right dynamic linker even if a non-standard 531 * one is being used. 532 */ 533 if (obj_main->interp != NULL && 534 strcmp(obj_main->interp, obj_rtld.path) != 0) { 535 free(obj_rtld.path); 536 obj_rtld.path = xstrdup(obj_main->interp); 537 __progname = obj_rtld.path; 538 } 539 #endif 540 541 digest_dynamic(obj_main, 0); 542 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 543 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 544 obj_main->dynsymcount); 545 546 linkmap_add(obj_main); 547 linkmap_add(&obj_rtld); 548 549 /* Link the main program into the list of objects. */ 550 *obj_tail = obj_main; 551 obj_tail = &obj_main->next; 552 obj_count++; 553 obj_loads++; 554 555 /* Initialize a fake symbol for resolving undefined weak references. */ 556 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 557 sym_zero.st_shndx = SHN_UNDEF; 558 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 559 560 if (!libmap_disable) 561 libmap_disable = (bool)lm_init(libmap_override); 562 563 dbg("loading LD_PRELOAD libraries"); 564 if (load_preload_objects() == -1) 565 rtld_die(); 566 preload_tail = obj_tail; 567 568 dbg("loading needed objects"); 569 if (load_needed_objects(obj_main, 0) == -1) 570 rtld_die(); 571 572 /* Make a list of all objects loaded at startup. */ 573 last_interposer = obj_main; 574 for (obj = obj_list; obj != NULL; obj = obj->next) { 575 if (obj->z_interpose && obj != obj_main) { 576 objlist_put_after(&list_main, last_interposer, obj); 577 last_interposer = obj; 578 } else { 579 objlist_push_tail(&list_main, obj); 580 } 581 obj->refcount++; 582 } 583 584 dbg("checking for required versions"); 585 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 586 rtld_die(); 587 588 if (ld_tracing) { /* We're done */ 589 trace_loaded_objects(obj_main); 590 exit(0); 591 } 592 593 if (getenv(LD_ "DUMP_REL_PRE") != NULL) { 594 dump_relocations(obj_main); 595 exit (0); 596 } 597 598 /* 599 * Processing tls relocations requires having the tls offsets 600 * initialized. Prepare offsets before starting initial 601 * relocation processing. 602 */ 603 dbg("initializing initial thread local storage offsets"); 604 STAILQ_FOREACH(entry, &list_main, link) { 605 /* 606 * Allocate all the initial objects out of the static TLS 607 * block even if they didn't ask for it. 608 */ 609 allocate_tls_offset(entry->obj); 610 } 611 612 if (relocate_objects(obj_main, 613 ld_bind_now != NULL && *ld_bind_now != '\0', 614 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 615 rtld_die(); 616 617 dbg("doing copy relocations"); 618 if (do_copy_relocations(obj_main) == -1) 619 rtld_die(); 620 621 if (getenv(LD_ "DUMP_REL_POST") != NULL) { 622 dump_relocations(obj_main); 623 exit (0); 624 } 625 626 /* 627 * Setup TLS for main thread. This must be done after the 628 * relocations are processed, since tls initialization section 629 * might be the subject for relocations. 630 */ 631 dbg("initializing initial thread local storage"); 632 allocate_initial_tls(obj_list); 633 634 dbg("initializing key program variables"); 635 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 636 set_program_var("environ", env); 637 set_program_var("__elf_aux_vector", aux); 638 639 /* Make a list of init functions to call. */ 640 objlist_init(&initlist); 641 initlist_add_objects(obj_list, preload_tail, &initlist); 642 643 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 644 645 map_stacks_exec(NULL); 646 647 dbg("resolving ifuncs"); 648 if (resolve_objects_ifunc(obj_main, 649 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY, 650 NULL) == -1) 651 rtld_die(); 652 653 if (!obj_main->crt_no_init) { 654 /* 655 * Make sure we don't call the main program's init and fini 656 * functions for binaries linked with old crt1 which calls 657 * _init itself. 658 */ 659 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 660 obj_main->preinit_array = obj_main->init_array = 661 obj_main->fini_array = (Elf_Addr)NULL; 662 } 663 664 wlock_acquire(rtld_bind_lock, &lockstate); 665 if (obj_main->crt_no_init) 666 preinit_main(); 667 objlist_call_init(&initlist, &lockstate); 668 _r_debug_postinit(&obj_main->linkmap); 669 objlist_clear(&initlist); 670 dbg("loading filtees"); 671 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 672 if (ld_loadfltr || obj->z_loadfltr) 673 load_filtees(obj, 0, &lockstate); 674 } 675 lock_release(rtld_bind_lock, &lockstate); 676 677 dbg("transferring control to program entry point = %p", obj_main->entry); 678 679 /* Return the exit procedure and the program entry point. */ 680 *exit_proc = rtld_exit; 681 *objp = obj_main; 682 return (func_ptr_type) obj_main->entry; 683 } 684 685 void * 686 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 687 { 688 void *ptr; 689 Elf_Addr target; 690 691 ptr = (void *)make_function_pointer(def, obj); 692 target = ((Elf_Addr (*)(void))ptr)(); 693 return ((void *)target); 694 } 695 696 Elf_Addr 697 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 698 { 699 const Elf_Rel *rel; 700 const Elf_Sym *def; 701 const Obj_Entry *defobj; 702 Elf_Addr *where; 703 Elf_Addr target; 704 RtldLockState lockstate; 705 706 rlock_acquire(rtld_bind_lock, &lockstate); 707 if (sigsetjmp(lockstate.env, 0) != 0) 708 lock_upgrade(rtld_bind_lock, &lockstate); 709 if (obj->pltrel) 710 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 711 else 712 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 713 714 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 715 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL, 716 &lockstate); 717 if (def == NULL) 718 rtld_die(); 719 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 720 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 721 else 722 target = (Elf_Addr)(defobj->relocbase + def->st_value); 723 724 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 725 defobj->strtab + def->st_name, basename(obj->path), 726 (void *)target, basename(defobj->path)); 727 728 /* 729 * Write the new contents for the jmpslot. Note that depending on 730 * architecture, the value which we need to return back to the 731 * lazy binding trampoline may or may not be the target 732 * address. The value returned from reloc_jmpslot() is the value 733 * that the trampoline needs. 734 */ 735 target = reloc_jmpslot(where, target, defobj, obj, rel); 736 lock_release(rtld_bind_lock, &lockstate); 737 return target; 738 } 739 740 /* 741 * Error reporting function. Use it like printf. If formats the message 742 * into a buffer, and sets things up so that the next call to dlerror() 743 * will return the message. 744 */ 745 void 746 _rtld_error(const char *fmt, ...) 747 { 748 static char buf[512]; 749 va_list ap; 750 751 va_start(ap, fmt); 752 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 753 error_message = buf; 754 va_end(ap); 755 } 756 757 /* 758 * Return a dynamically-allocated copy of the current error message, if any. 759 */ 760 static char * 761 errmsg_save(void) 762 { 763 return error_message == NULL ? NULL : xstrdup(error_message); 764 } 765 766 /* 767 * Restore the current error message from a copy which was previously saved 768 * by errmsg_save(). The copy is freed. 769 */ 770 static void 771 errmsg_restore(char *saved_msg) 772 { 773 if (saved_msg == NULL) 774 error_message = NULL; 775 else { 776 _rtld_error("%s", saved_msg); 777 free(saved_msg); 778 } 779 } 780 781 static const char * 782 basename(const char *name) 783 { 784 const char *p = strrchr(name, '/'); 785 return p != NULL ? p + 1 : name; 786 } 787 788 static struct utsname uts; 789 790 static char * 791 origin_subst_one(char *real, const char *kw, const char *subst, 792 bool may_free) 793 { 794 char *p, *p1, *res, *resp; 795 int subst_len, kw_len, subst_count, old_len, new_len; 796 797 kw_len = strlen(kw); 798 799 /* 800 * First, count the number of the keyword occurences, to 801 * preallocate the final string. 802 */ 803 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 804 p1 = strstr(p, kw); 805 if (p1 == NULL) 806 break; 807 } 808 809 /* 810 * If the keyword is not found, just return. 811 */ 812 if (subst_count == 0) 813 return (may_free ? real : xstrdup(real)); 814 815 /* 816 * There is indeed something to substitute. Calculate the 817 * length of the resulting string, and allocate it. 818 */ 819 subst_len = strlen(subst); 820 old_len = strlen(real); 821 new_len = old_len + (subst_len - kw_len) * subst_count; 822 res = xmalloc(new_len + 1); 823 824 /* 825 * Now, execute the substitution loop. 826 */ 827 for (p = real, resp = res, *resp = '\0';;) { 828 p1 = strstr(p, kw); 829 if (p1 != NULL) { 830 /* Copy the prefix before keyword. */ 831 memcpy(resp, p, p1 - p); 832 resp += p1 - p; 833 /* Keyword replacement. */ 834 memcpy(resp, subst, subst_len); 835 resp += subst_len; 836 *resp = '\0'; 837 p = p1 + kw_len; 838 } else 839 break; 840 } 841 842 /* Copy to the end of string and finish. */ 843 strcat(resp, p); 844 if (may_free) 845 free(real); 846 return (res); 847 } 848 849 static char * 850 origin_subst(char *real, const char *origin_path) 851 { 852 char *res1, *res2, *res3, *res4; 853 854 if (uts.sysname[0] == '\0') { 855 if (uname(&uts) != 0) { 856 _rtld_error("utsname failed: %d", errno); 857 return (NULL); 858 } 859 } 860 res1 = origin_subst_one(real, "$ORIGIN", origin_path, false); 861 res2 = origin_subst_one(res1, "$OSNAME", uts.sysname, true); 862 res3 = origin_subst_one(res2, "$OSREL", uts.release, true); 863 res4 = origin_subst_one(res3, "$PLATFORM", uts.machine, true); 864 return (res4); 865 } 866 867 void 868 rtld_die(void) 869 { 870 const char *msg = dlerror(); 871 872 if (msg == NULL) 873 msg = "Fatal error"; 874 rtld_fdputstr(STDERR_FILENO, msg); 875 rtld_fdputchar(STDERR_FILENO, '\n'); 876 _exit(1); 877 } 878 879 /* 880 * Process a shared object's DYNAMIC section, and save the important 881 * information in its Obj_Entry structure. 882 */ 883 static void 884 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 885 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 886 { 887 const Elf_Dyn *dynp; 888 Needed_Entry **needed_tail = &obj->needed; 889 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 890 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 891 const Elf_Hashelt *hashtab; 892 const Elf32_Word *hashval; 893 Elf32_Word bkt, nmaskwords; 894 int bloom_size32; 895 int plttype = DT_REL; 896 897 *dyn_rpath = NULL; 898 *dyn_soname = NULL; 899 *dyn_runpath = NULL; 900 901 obj->bind_now = false; 902 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 903 switch (dynp->d_tag) { 904 905 case DT_REL: 906 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 907 break; 908 909 case DT_RELSZ: 910 obj->relsize = dynp->d_un.d_val; 911 break; 912 913 case DT_RELENT: 914 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 915 break; 916 917 case DT_JMPREL: 918 obj->pltrel = (const Elf_Rel *) 919 (obj->relocbase + dynp->d_un.d_ptr); 920 break; 921 922 case DT_PLTRELSZ: 923 obj->pltrelsize = dynp->d_un.d_val; 924 break; 925 926 case DT_RELA: 927 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 928 break; 929 930 case DT_RELASZ: 931 obj->relasize = dynp->d_un.d_val; 932 break; 933 934 case DT_RELAENT: 935 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 936 break; 937 938 case DT_PLTREL: 939 plttype = dynp->d_un.d_val; 940 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 941 break; 942 943 case DT_SYMTAB: 944 obj->symtab = (const Elf_Sym *) 945 (obj->relocbase + dynp->d_un.d_ptr); 946 break; 947 948 case DT_SYMENT: 949 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 950 break; 951 952 case DT_STRTAB: 953 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 954 break; 955 956 case DT_STRSZ: 957 obj->strsize = dynp->d_un.d_val; 958 break; 959 960 case DT_VERNEED: 961 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 962 dynp->d_un.d_val); 963 break; 964 965 case DT_VERNEEDNUM: 966 obj->verneednum = dynp->d_un.d_val; 967 break; 968 969 case DT_VERDEF: 970 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 971 dynp->d_un.d_val); 972 break; 973 974 case DT_VERDEFNUM: 975 obj->verdefnum = dynp->d_un.d_val; 976 break; 977 978 case DT_VERSYM: 979 obj->versyms = (const Elf_Versym *)(obj->relocbase + 980 dynp->d_un.d_val); 981 break; 982 983 case DT_HASH: 984 { 985 hashtab = (const Elf_Hashelt *)(obj->relocbase + 986 dynp->d_un.d_ptr); 987 obj->nbuckets = hashtab[0]; 988 obj->nchains = hashtab[1]; 989 obj->buckets = hashtab + 2; 990 obj->chains = obj->buckets + obj->nbuckets; 991 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 992 obj->buckets != NULL; 993 } 994 break; 995 996 case DT_GNU_HASH: 997 { 998 hashtab = (const Elf_Hashelt *)(obj->relocbase + 999 dynp->d_un.d_ptr); 1000 obj->nbuckets_gnu = hashtab[0]; 1001 obj->symndx_gnu = hashtab[1]; 1002 nmaskwords = hashtab[2]; 1003 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1004 obj->maskwords_bm_gnu = nmaskwords - 1; 1005 obj->shift2_gnu = hashtab[3]; 1006 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4); 1007 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1008 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1009 obj->symndx_gnu; 1010 /* Number of bitmask words is required to be power of 2 */ 1011 obj->valid_hash_gnu = powerof2(nmaskwords) && 1012 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1013 } 1014 break; 1015 1016 case DT_NEEDED: 1017 if (!obj->rtld) { 1018 Needed_Entry *nep = NEW(Needed_Entry); 1019 nep->name = dynp->d_un.d_val; 1020 nep->obj = NULL; 1021 nep->next = NULL; 1022 1023 *needed_tail = nep; 1024 needed_tail = &nep->next; 1025 } 1026 break; 1027 1028 case DT_FILTER: 1029 if (!obj->rtld) { 1030 Needed_Entry *nep = NEW(Needed_Entry); 1031 nep->name = dynp->d_un.d_val; 1032 nep->obj = NULL; 1033 nep->next = NULL; 1034 1035 *needed_filtees_tail = nep; 1036 needed_filtees_tail = &nep->next; 1037 } 1038 break; 1039 1040 case DT_AUXILIARY: 1041 if (!obj->rtld) { 1042 Needed_Entry *nep = NEW(Needed_Entry); 1043 nep->name = dynp->d_un.d_val; 1044 nep->obj = NULL; 1045 nep->next = NULL; 1046 1047 *needed_aux_filtees_tail = nep; 1048 needed_aux_filtees_tail = &nep->next; 1049 } 1050 break; 1051 1052 case DT_PLTGOT: 1053 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 1054 break; 1055 1056 case DT_TEXTREL: 1057 obj->textrel = true; 1058 break; 1059 1060 case DT_SYMBOLIC: 1061 obj->symbolic = true; 1062 break; 1063 1064 case DT_RPATH: 1065 /* 1066 * We have to wait until later to process this, because we 1067 * might not have gotten the address of the string table yet. 1068 */ 1069 *dyn_rpath = dynp; 1070 break; 1071 1072 case DT_SONAME: 1073 *dyn_soname = dynp; 1074 break; 1075 1076 case DT_RUNPATH: 1077 *dyn_runpath = dynp; 1078 break; 1079 1080 case DT_INIT: 1081 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1082 break; 1083 1084 case DT_PREINIT_ARRAY: 1085 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1086 break; 1087 1088 case DT_PREINIT_ARRAYSZ: 1089 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1090 break; 1091 1092 case DT_INIT_ARRAY: 1093 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1094 break; 1095 1096 case DT_INIT_ARRAYSZ: 1097 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1098 break; 1099 1100 case DT_FINI: 1101 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1102 break; 1103 1104 case DT_FINI_ARRAY: 1105 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1106 break; 1107 1108 case DT_FINI_ARRAYSZ: 1109 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1110 break; 1111 1112 /* 1113 * Don't process DT_DEBUG on MIPS as the dynamic section 1114 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1115 */ 1116 1117 #ifndef __mips__ 1118 case DT_DEBUG: 1119 /* XXX - not implemented yet */ 1120 if (!early) 1121 dbg("Filling in DT_DEBUG entry"); 1122 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 1123 break; 1124 #endif 1125 1126 case DT_FLAGS: 1127 if ((dynp->d_un.d_val & DF_ORIGIN) && trust) 1128 obj->z_origin = true; 1129 if (dynp->d_un.d_val & DF_SYMBOLIC) 1130 obj->symbolic = true; 1131 if (dynp->d_un.d_val & DF_TEXTREL) 1132 obj->textrel = true; 1133 if (dynp->d_un.d_val & DF_BIND_NOW) 1134 obj->bind_now = true; 1135 /*if (dynp->d_un.d_val & DF_STATIC_TLS) 1136 ;*/ 1137 break; 1138 #ifdef __mips__ 1139 case DT_MIPS_LOCAL_GOTNO: 1140 obj->local_gotno = dynp->d_un.d_val; 1141 break; 1142 1143 case DT_MIPS_SYMTABNO: 1144 obj->symtabno = dynp->d_un.d_val; 1145 break; 1146 1147 case DT_MIPS_GOTSYM: 1148 obj->gotsym = dynp->d_un.d_val; 1149 break; 1150 1151 case DT_MIPS_RLD_MAP: 1152 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1153 break; 1154 #endif 1155 1156 case DT_FLAGS_1: 1157 if (dynp->d_un.d_val & DF_1_NOOPEN) 1158 obj->z_noopen = true; 1159 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust) 1160 obj->z_origin = true; 1161 /*if (dynp->d_un.d_val & DF_1_GLOBAL) 1162 XXX ;*/ 1163 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1164 obj->bind_now = true; 1165 if (dynp->d_un.d_val & DF_1_NODELETE) 1166 obj->z_nodelete = true; 1167 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1168 obj->z_loadfltr = true; 1169 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1170 obj->z_interpose = true; 1171 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1172 obj->z_nodeflib = true; 1173 break; 1174 1175 default: 1176 if (!early) { 1177 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1178 (long)dynp->d_tag); 1179 } 1180 break; 1181 } 1182 } 1183 1184 obj->traced = false; 1185 1186 if (plttype == DT_RELA) { 1187 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1188 obj->pltrel = NULL; 1189 obj->pltrelasize = obj->pltrelsize; 1190 obj->pltrelsize = 0; 1191 } 1192 1193 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1194 if (obj->valid_hash_sysv) 1195 obj->dynsymcount = obj->nchains; 1196 else if (obj->valid_hash_gnu) { 1197 obj->dynsymcount = 0; 1198 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1199 if (obj->buckets_gnu[bkt] == 0) 1200 continue; 1201 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1202 do 1203 obj->dynsymcount++; 1204 while ((*hashval++ & 1u) == 0); 1205 } 1206 obj->dynsymcount += obj->symndx_gnu; 1207 } 1208 } 1209 1210 static void 1211 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1212 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1213 { 1214 1215 if (obj->z_origin && obj->origin_path == NULL) { 1216 obj->origin_path = xmalloc(PATH_MAX); 1217 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1) 1218 rtld_die(); 1219 } 1220 1221 if (dyn_runpath != NULL) { 1222 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val; 1223 if (obj->z_origin) 1224 obj->runpath = origin_subst(obj->runpath, obj->origin_path); 1225 } 1226 else if (dyn_rpath != NULL) { 1227 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 1228 if (obj->z_origin) 1229 obj->rpath = origin_subst(obj->rpath, obj->origin_path); 1230 } 1231 1232 if (dyn_soname != NULL) 1233 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1234 } 1235 1236 static void 1237 digest_dynamic(Obj_Entry *obj, int early) 1238 { 1239 const Elf_Dyn *dyn_rpath; 1240 const Elf_Dyn *dyn_soname; 1241 const Elf_Dyn *dyn_runpath; 1242 1243 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1244 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath); 1245 } 1246 1247 /* 1248 * Process a shared object's program header. This is used only for the 1249 * main program, when the kernel has already loaded the main program 1250 * into memory before calling the dynamic linker. It creates and 1251 * returns an Obj_Entry structure. 1252 */ 1253 static Obj_Entry * 1254 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1255 { 1256 Obj_Entry *obj; 1257 const Elf_Phdr *phlimit = phdr + phnum; 1258 const Elf_Phdr *ph; 1259 Elf_Addr note_start, note_end; 1260 int nsegs = 0; 1261 1262 obj = obj_new(); 1263 for (ph = phdr; ph < phlimit; ph++) { 1264 if (ph->p_type != PT_PHDR) 1265 continue; 1266 1267 obj->phdr = phdr; 1268 obj->phsize = ph->p_memsz; 1269 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1270 break; 1271 } 1272 1273 obj->stack_flags = PF_X | PF_R | PF_W; 1274 1275 for (ph = phdr; ph < phlimit; ph++) { 1276 switch (ph->p_type) { 1277 1278 case PT_INTERP: 1279 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1280 break; 1281 1282 case PT_LOAD: 1283 if (nsegs == 0) { /* First load segment */ 1284 obj->vaddrbase = trunc_page(ph->p_vaddr); 1285 obj->mapbase = obj->vaddrbase + obj->relocbase; 1286 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1287 obj->vaddrbase; 1288 } else { /* Last load segment */ 1289 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1290 obj->vaddrbase; 1291 } 1292 nsegs++; 1293 break; 1294 1295 case PT_DYNAMIC: 1296 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1297 break; 1298 1299 case PT_TLS: 1300 obj->tlsindex = 1; 1301 obj->tlssize = ph->p_memsz; 1302 obj->tlsalign = ph->p_align; 1303 obj->tlsinitsize = ph->p_filesz; 1304 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1305 break; 1306 1307 case PT_GNU_STACK: 1308 obj->stack_flags = ph->p_flags; 1309 break; 1310 1311 case PT_GNU_RELRO: 1312 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1313 obj->relro_size = round_page(ph->p_memsz); 1314 break; 1315 1316 case PT_NOTE: 1317 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1318 note_end = note_start + ph->p_filesz; 1319 digest_notes(obj, note_start, note_end); 1320 break; 1321 } 1322 } 1323 if (nsegs < 1) { 1324 _rtld_error("%s: too few PT_LOAD segments", path); 1325 return NULL; 1326 } 1327 1328 obj->entry = entry; 1329 return obj; 1330 } 1331 1332 void 1333 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1334 { 1335 const Elf_Note *note; 1336 const char *note_name; 1337 uintptr_t p; 1338 1339 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1340 note = (const Elf_Note *)((const char *)(note + 1) + 1341 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1342 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1343 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1344 note->n_descsz != sizeof(int32_t)) 1345 continue; 1346 if (note->n_type != ABI_NOTETYPE && 1347 note->n_type != CRT_NOINIT_NOTETYPE) 1348 continue; 1349 note_name = (const char *)(note + 1); 1350 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1351 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1352 continue; 1353 switch (note->n_type) { 1354 case ABI_NOTETYPE: 1355 /* FreeBSD osrel note */ 1356 p = (uintptr_t)(note + 1); 1357 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1358 obj->osrel = *(const int32_t *)(p); 1359 dbg("note osrel %d", obj->osrel); 1360 break; 1361 case CRT_NOINIT_NOTETYPE: 1362 /* FreeBSD 'crt does not call init' note */ 1363 obj->crt_no_init = true; 1364 dbg("note crt_no_init"); 1365 break; 1366 } 1367 } 1368 } 1369 1370 static Obj_Entry * 1371 dlcheck(void *handle) 1372 { 1373 Obj_Entry *obj; 1374 1375 for (obj = obj_list; obj != NULL; obj = obj->next) 1376 if (obj == (Obj_Entry *) handle) 1377 break; 1378 1379 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1380 _rtld_error("Invalid shared object handle %p", handle); 1381 return NULL; 1382 } 1383 return obj; 1384 } 1385 1386 /* 1387 * If the given object is already in the donelist, return true. Otherwise 1388 * add the object to the list and return false. 1389 */ 1390 static bool 1391 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1392 { 1393 unsigned int i; 1394 1395 for (i = 0; i < dlp->num_used; i++) 1396 if (dlp->objs[i] == obj) 1397 return true; 1398 /* 1399 * Our donelist allocation should always be sufficient. But if 1400 * our threads locking isn't working properly, more shared objects 1401 * could have been loaded since we allocated the list. That should 1402 * never happen, but we'll handle it properly just in case it does. 1403 */ 1404 if (dlp->num_used < dlp->num_alloc) 1405 dlp->objs[dlp->num_used++] = obj; 1406 return false; 1407 } 1408 1409 /* 1410 * Hash function for symbol table lookup. Don't even think about changing 1411 * this. It is specified by the System V ABI. 1412 */ 1413 unsigned long 1414 elf_hash(const char *name) 1415 { 1416 const unsigned char *p = (const unsigned char *) name; 1417 unsigned long h = 0; 1418 unsigned long g; 1419 1420 while (*p != '\0') { 1421 h = (h << 4) + *p++; 1422 if ((g = h & 0xf0000000) != 0) 1423 h ^= g >> 24; 1424 h &= ~g; 1425 } 1426 return h; 1427 } 1428 1429 /* 1430 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1431 * unsigned in case it's implemented with a wider type. 1432 */ 1433 static uint32_t 1434 gnu_hash(const char *s) 1435 { 1436 uint32_t h; 1437 unsigned char c; 1438 1439 h = 5381; 1440 for (c = *s; c != '\0'; c = *++s) 1441 h = h * 33 + c; 1442 return (h & 0xffffffff); 1443 } 1444 1445 1446 /* 1447 * Find the library with the given name, and return its full pathname. 1448 * The returned string is dynamically allocated. Generates an error 1449 * message and returns NULL if the library cannot be found. 1450 * 1451 * If the second argument is non-NULL, then it refers to an already- 1452 * loaded shared object, whose library search path will be searched. 1453 * 1454 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1455 * descriptor (which is close-on-exec) will be passed out via the third 1456 * argument. 1457 * 1458 * The search order is: 1459 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1460 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1461 * LD_LIBRARY_PATH 1462 * DT_RUNPATH in the referencing file 1463 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1464 * from list) 1465 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1466 * 1467 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1468 */ 1469 static char * 1470 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1471 { 1472 char *pathname; 1473 char *name; 1474 bool nodeflib, objgiven; 1475 1476 objgiven = refobj != NULL; 1477 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */ 1478 if (xname[0] != '/' && !trust) { 1479 _rtld_error("Absolute pathname required for shared object \"%s\"", 1480 xname); 1481 return NULL; 1482 } 1483 if (objgiven && refobj->z_origin) { 1484 return (origin_subst(__DECONST(char *, xname), 1485 refobj->origin_path)); 1486 } else { 1487 return (xstrdup(xname)); 1488 } 1489 } 1490 1491 if (libmap_disable || !objgiven || 1492 (name = lm_find(refobj->path, xname)) == NULL) 1493 name = (char *)xname; 1494 1495 dbg(" Searching for \"%s\"", name); 1496 1497 /* 1498 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1499 * back to pre-conforming behaviour if user requested so with 1500 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1501 * nodeflib. 1502 */ 1503 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1504 if ((pathname = search_library_path(name, ld_library_path)) != NULL || 1505 (refobj != NULL && 1506 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1507 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL || 1508 (pathname = search_library_path(name, gethints(false))) != NULL || 1509 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL) 1510 return (pathname); 1511 } else { 1512 nodeflib = objgiven ? refobj->z_nodeflib : false; 1513 if ((objgiven && 1514 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1515 (objgiven && refobj->runpath == NULL && refobj != obj_main && 1516 (pathname = search_library_path(name, obj_main->rpath)) != NULL) || 1517 (pathname = search_library_path(name, ld_library_path)) != NULL || 1518 (objgiven && 1519 (pathname = search_library_path(name, refobj->runpath)) != NULL) || 1520 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL || 1521 (pathname = search_library_path(name, gethints(nodeflib))) != NULL || 1522 (objgiven && !nodeflib && 1523 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)) 1524 return (pathname); 1525 } 1526 1527 if (objgiven && refobj->path != NULL) { 1528 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 1529 name, basename(refobj->path)); 1530 } else { 1531 _rtld_error("Shared object \"%s\" not found", name); 1532 } 1533 return NULL; 1534 } 1535 1536 /* 1537 * Given a symbol number in a referencing object, find the corresponding 1538 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1539 * no definition was found. Returns a pointer to the Obj_Entry of the 1540 * defining object via the reference parameter DEFOBJ_OUT. 1541 */ 1542 const Elf_Sym * 1543 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1544 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1545 RtldLockState *lockstate) 1546 { 1547 const Elf_Sym *ref; 1548 const Elf_Sym *def; 1549 const Obj_Entry *defobj; 1550 SymLook req; 1551 const char *name; 1552 int res; 1553 1554 /* 1555 * If we have already found this symbol, get the information from 1556 * the cache. 1557 */ 1558 if (symnum >= refobj->dynsymcount) 1559 return NULL; /* Bad object */ 1560 if (cache != NULL && cache[symnum].sym != NULL) { 1561 *defobj_out = cache[symnum].obj; 1562 return cache[symnum].sym; 1563 } 1564 1565 ref = refobj->symtab + symnum; 1566 name = refobj->strtab + ref->st_name; 1567 def = NULL; 1568 defobj = NULL; 1569 1570 /* 1571 * We don't have to do a full scale lookup if the symbol is local. 1572 * We know it will bind to the instance in this load module; to 1573 * which we already have a pointer (ie ref). By not doing a lookup, 1574 * we not only improve performance, but it also avoids unresolvable 1575 * symbols when local symbols are not in the hash table. This has 1576 * been seen with the ia64 toolchain. 1577 */ 1578 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1579 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1580 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1581 symnum); 1582 } 1583 symlook_init(&req, name); 1584 req.flags = flags; 1585 req.ventry = fetch_ventry(refobj, symnum); 1586 req.lockstate = lockstate; 1587 res = symlook_default(&req, refobj); 1588 if (res == 0) { 1589 def = req.sym_out; 1590 defobj = req.defobj_out; 1591 } 1592 } else { 1593 def = ref; 1594 defobj = refobj; 1595 } 1596 1597 /* 1598 * If we found no definition and the reference is weak, treat the 1599 * symbol as having the value zero. 1600 */ 1601 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1602 def = &sym_zero; 1603 defobj = obj_main; 1604 } 1605 1606 if (def != NULL) { 1607 *defobj_out = defobj; 1608 /* Record the information in the cache to avoid subsequent lookups. */ 1609 if (cache != NULL) { 1610 cache[symnum].sym = def; 1611 cache[symnum].obj = defobj; 1612 } 1613 } else { 1614 if (refobj != &obj_rtld) 1615 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name); 1616 } 1617 return def; 1618 } 1619 1620 /* 1621 * Return the search path from the ldconfig hints file, reading it if 1622 * necessary. If nostdlib is true, then the default search paths are 1623 * not added to result. 1624 * 1625 * Returns NULL if there are problems with the hints file, 1626 * or if the search path there is empty. 1627 */ 1628 static const char * 1629 gethints(bool nostdlib) 1630 { 1631 static char *hints, *filtered_path; 1632 struct elfhints_hdr hdr; 1633 struct fill_search_info_args sargs, hargs; 1634 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1635 struct dl_serpath *SLPpath, *hintpath; 1636 char *p; 1637 unsigned int SLPndx, hintndx, fndx, fcount; 1638 int fd; 1639 size_t flen; 1640 bool skip; 1641 1642 /* First call, read the hints file */ 1643 if (hints == NULL) { 1644 /* Keep from trying again in case the hints file is bad. */ 1645 hints = ""; 1646 1647 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1648 return (NULL); 1649 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1650 hdr.magic != ELFHINTS_MAGIC || 1651 hdr.version != 1) { 1652 close(fd); 1653 return (NULL); 1654 } 1655 p = xmalloc(hdr.dirlistlen + 1); 1656 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1657 read(fd, p, hdr.dirlistlen + 1) != 1658 (ssize_t)hdr.dirlistlen + 1) { 1659 free(p); 1660 close(fd); 1661 return (NULL); 1662 } 1663 hints = p; 1664 close(fd); 1665 } 1666 1667 /* 1668 * If caller agreed to receive list which includes the default 1669 * paths, we are done. Otherwise, if we still did not 1670 * calculated filtered result, do it now. 1671 */ 1672 if (!nostdlib) 1673 return (hints[0] != '\0' ? hints : NULL); 1674 if (filtered_path != NULL) 1675 goto filt_ret; 1676 1677 /* 1678 * Obtain the list of all configured search paths, and the 1679 * list of the default paths. 1680 * 1681 * First estimate the size of the results. 1682 */ 1683 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1684 smeta.dls_cnt = 0; 1685 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1686 hmeta.dls_cnt = 0; 1687 1688 sargs.request = RTLD_DI_SERINFOSIZE; 1689 sargs.serinfo = &smeta; 1690 hargs.request = RTLD_DI_SERINFOSIZE; 1691 hargs.serinfo = &hmeta; 1692 1693 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1694 path_enumerate(p, fill_search_info, &hargs); 1695 1696 SLPinfo = xmalloc(smeta.dls_size); 1697 hintinfo = xmalloc(hmeta.dls_size); 1698 1699 /* 1700 * Next fetch both sets of paths. 1701 */ 1702 sargs.request = RTLD_DI_SERINFO; 1703 sargs.serinfo = SLPinfo; 1704 sargs.serpath = &SLPinfo->dls_serpath[0]; 1705 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1706 1707 hargs.request = RTLD_DI_SERINFO; 1708 hargs.serinfo = hintinfo; 1709 hargs.serpath = &hintinfo->dls_serpath[0]; 1710 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1711 1712 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1713 path_enumerate(p, fill_search_info, &hargs); 1714 1715 /* 1716 * Now calculate the difference between two sets, by excluding 1717 * standard paths from the full set. 1718 */ 1719 fndx = 0; 1720 fcount = 0; 1721 filtered_path = xmalloc(hdr.dirlistlen + 1); 1722 hintpath = &hintinfo->dls_serpath[0]; 1723 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1724 skip = false; 1725 SLPpath = &SLPinfo->dls_serpath[0]; 1726 /* 1727 * Check each standard path against current. 1728 */ 1729 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1730 /* matched, skip the path */ 1731 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1732 skip = true; 1733 break; 1734 } 1735 } 1736 if (skip) 1737 continue; 1738 /* 1739 * Not matched against any standard path, add the path 1740 * to result. Separate consequtive paths with ':'. 1741 */ 1742 if (fcount > 0) { 1743 filtered_path[fndx] = ':'; 1744 fndx++; 1745 } 1746 fcount++; 1747 flen = strlen(hintpath->dls_name); 1748 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1749 fndx += flen; 1750 } 1751 filtered_path[fndx] = '\0'; 1752 1753 free(SLPinfo); 1754 free(hintinfo); 1755 1756 filt_ret: 1757 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1758 } 1759 1760 static void 1761 init_dag(Obj_Entry *root) 1762 { 1763 const Needed_Entry *needed; 1764 const Objlist_Entry *elm; 1765 DoneList donelist; 1766 1767 if (root->dag_inited) 1768 return; 1769 donelist_init(&donelist); 1770 1771 /* Root object belongs to own DAG. */ 1772 objlist_push_tail(&root->dldags, root); 1773 objlist_push_tail(&root->dagmembers, root); 1774 donelist_check(&donelist, root); 1775 1776 /* 1777 * Add dependencies of root object to DAG in breadth order 1778 * by exploiting the fact that each new object get added 1779 * to the tail of the dagmembers list. 1780 */ 1781 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1782 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1783 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1784 continue; 1785 objlist_push_tail(&needed->obj->dldags, root); 1786 objlist_push_tail(&root->dagmembers, needed->obj); 1787 } 1788 } 1789 root->dag_inited = true; 1790 } 1791 1792 static void 1793 process_nodelete(Obj_Entry *root) 1794 { 1795 const Objlist_Entry *elm; 1796 1797 /* 1798 * Walk over object DAG and process every dependent object that 1799 * is marked as DF_1_NODELETE. They need to grow their own DAG, 1800 * which then should have its reference upped separately. 1801 */ 1802 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1803 if (elm->obj != NULL && elm->obj->z_nodelete && 1804 !elm->obj->ref_nodel) { 1805 dbg("obj %s nodelete", elm->obj->path); 1806 init_dag(elm->obj); 1807 ref_dag(elm->obj); 1808 elm->obj->ref_nodel = true; 1809 } 1810 } 1811 } 1812 /* 1813 * Initialize the dynamic linker. The argument is the address at which 1814 * the dynamic linker has been mapped into memory. The primary task of 1815 * this function is to relocate the dynamic linker. 1816 */ 1817 static void 1818 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 1819 { 1820 Obj_Entry objtmp; /* Temporary rtld object */ 1821 const Elf_Dyn *dyn_rpath; 1822 const Elf_Dyn *dyn_soname; 1823 const Elf_Dyn *dyn_runpath; 1824 1825 #ifdef RTLD_INIT_PAGESIZES_EARLY 1826 /* The page size is required by the dynamic memory allocator. */ 1827 init_pagesizes(aux_info); 1828 #endif 1829 1830 /* 1831 * Conjure up an Obj_Entry structure for the dynamic linker. 1832 * 1833 * The "path" member can't be initialized yet because string constants 1834 * cannot yet be accessed. Below we will set it correctly. 1835 */ 1836 memset(&objtmp, 0, sizeof(objtmp)); 1837 objtmp.path = NULL; 1838 objtmp.rtld = true; 1839 objtmp.mapbase = mapbase; 1840 #ifdef PIC 1841 objtmp.relocbase = mapbase; 1842 #endif 1843 if (RTLD_IS_DYNAMIC()) { 1844 objtmp.dynamic = rtld_dynamic(&objtmp); 1845 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 1846 assert(objtmp.needed == NULL); 1847 #if !defined(__mips__) 1848 /* MIPS has a bogus DT_TEXTREL. */ 1849 assert(!objtmp.textrel); 1850 #endif 1851 1852 /* 1853 * Temporarily put the dynamic linker entry into the object list, so 1854 * that symbols can be found. 1855 */ 1856 1857 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 1858 } 1859 1860 /* Initialize the object list. */ 1861 obj_tail = &obj_list; 1862 1863 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1864 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1865 1866 #ifndef RTLD_INIT_PAGESIZES_EARLY 1867 /* The page size is required by the dynamic memory allocator. */ 1868 init_pagesizes(aux_info); 1869 #endif 1870 1871 if (aux_info[AT_OSRELDATE] != NULL) 1872 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 1873 1874 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 1875 1876 /* Replace the path with a dynamically allocated copy. */ 1877 obj_rtld.path = xstrdup(PATH_RTLD); 1878 1879 r_debug.r_brk = r_debug_state; 1880 r_debug.r_state = RT_CONSISTENT; 1881 } 1882 1883 /* 1884 * Retrieve the array of supported page sizes. The kernel provides the page 1885 * sizes in increasing order. 1886 */ 1887 static void 1888 init_pagesizes(Elf_Auxinfo **aux_info) 1889 { 1890 static size_t psa[MAXPAGESIZES]; 1891 int mib[2]; 1892 size_t len, size; 1893 1894 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 1895 NULL) { 1896 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 1897 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 1898 } else { 1899 len = 2; 1900 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 1901 size = sizeof(psa); 1902 else { 1903 /* As a fallback, retrieve the base page size. */ 1904 size = sizeof(psa[0]); 1905 if (aux_info[AT_PAGESZ] != NULL) { 1906 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 1907 goto psa_filled; 1908 } else { 1909 mib[0] = CTL_HW; 1910 mib[1] = HW_PAGESIZE; 1911 len = 2; 1912 } 1913 } 1914 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 1915 _rtld_error("sysctl for hw.pagesize(s) failed"); 1916 rtld_die(); 1917 } 1918 psa_filled: 1919 pagesizes = psa; 1920 } 1921 npagesizes = size / sizeof(pagesizes[0]); 1922 /* Discard any invalid entries at the end of the array. */ 1923 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 1924 npagesizes--; 1925 } 1926 1927 /* 1928 * Add the init functions from a needed object list (and its recursive 1929 * needed objects) to "list". This is not used directly; it is a helper 1930 * function for initlist_add_objects(). The write lock must be held 1931 * when this function is called. 1932 */ 1933 static void 1934 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 1935 { 1936 /* Recursively process the successor needed objects. */ 1937 if (needed->next != NULL) 1938 initlist_add_neededs(needed->next, list); 1939 1940 /* Process the current needed object. */ 1941 if (needed->obj != NULL) 1942 initlist_add_objects(needed->obj, &needed->obj->next, list); 1943 } 1944 1945 /* 1946 * Scan all of the DAGs rooted in the range of objects from "obj" to 1947 * "tail" and add their init functions to "list". This recurses over 1948 * the DAGs and ensure the proper init ordering such that each object's 1949 * needed libraries are initialized before the object itself. At the 1950 * same time, this function adds the objects to the global finalization 1951 * list "list_fini" in the opposite order. The write lock must be 1952 * held when this function is called. 1953 */ 1954 static void 1955 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list) 1956 { 1957 1958 if (obj->init_scanned || obj->init_done) 1959 return; 1960 obj->init_scanned = true; 1961 1962 /* Recursively process the successor objects. */ 1963 if (&obj->next != tail) 1964 initlist_add_objects(obj->next, tail, list); 1965 1966 /* Recursively process the needed objects. */ 1967 if (obj->needed != NULL) 1968 initlist_add_neededs(obj->needed, list); 1969 if (obj->needed_filtees != NULL) 1970 initlist_add_neededs(obj->needed_filtees, list); 1971 if (obj->needed_aux_filtees != NULL) 1972 initlist_add_neededs(obj->needed_aux_filtees, list); 1973 1974 /* Add the object to the init list. */ 1975 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL || 1976 obj->init_array != (Elf_Addr)NULL) 1977 objlist_push_tail(list, obj); 1978 1979 /* Add the object to the global fini list in the reverse order. */ 1980 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 1981 && !obj->on_fini_list) { 1982 objlist_push_head(&list_fini, obj); 1983 obj->on_fini_list = true; 1984 } 1985 } 1986 1987 #ifndef FPTR_TARGET 1988 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 1989 #endif 1990 1991 static void 1992 free_needed_filtees(Needed_Entry *n) 1993 { 1994 Needed_Entry *needed, *needed1; 1995 1996 for (needed = n; needed != NULL; needed = needed->next) { 1997 if (needed->obj != NULL) { 1998 dlclose(needed->obj); 1999 needed->obj = NULL; 2000 } 2001 } 2002 for (needed = n; needed != NULL; needed = needed1) { 2003 needed1 = needed->next; 2004 free(needed); 2005 } 2006 } 2007 2008 static void 2009 unload_filtees(Obj_Entry *obj) 2010 { 2011 2012 free_needed_filtees(obj->needed_filtees); 2013 obj->needed_filtees = NULL; 2014 free_needed_filtees(obj->needed_aux_filtees); 2015 obj->needed_aux_filtees = NULL; 2016 obj->filtees_loaded = false; 2017 } 2018 2019 static void 2020 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2021 RtldLockState *lockstate) 2022 { 2023 2024 for (; needed != NULL; needed = needed->next) { 2025 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2026 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2027 RTLD_LOCAL, lockstate); 2028 } 2029 } 2030 2031 static void 2032 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2033 { 2034 2035 lock_restart_for_upgrade(lockstate); 2036 if (!obj->filtees_loaded) { 2037 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2038 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2039 obj->filtees_loaded = true; 2040 } 2041 } 2042 2043 static int 2044 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2045 { 2046 Obj_Entry *obj1; 2047 2048 for (; needed != NULL; needed = needed->next) { 2049 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2050 flags & ~RTLD_LO_NOLOAD); 2051 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2052 return (-1); 2053 } 2054 return (0); 2055 } 2056 2057 /* 2058 * Given a shared object, traverse its list of needed objects, and load 2059 * each of them. Returns 0 on success. Generates an error message and 2060 * returns -1 on failure. 2061 */ 2062 static int 2063 load_needed_objects(Obj_Entry *first, int flags) 2064 { 2065 Obj_Entry *obj; 2066 2067 for (obj = first; obj != NULL; obj = obj->next) { 2068 if (process_needed(obj, obj->needed, flags) == -1) 2069 return (-1); 2070 } 2071 return (0); 2072 } 2073 2074 static int 2075 load_preload_objects(void) 2076 { 2077 char *p = ld_preload; 2078 Obj_Entry *obj; 2079 static const char delim[] = " \t:;"; 2080 2081 if (p == NULL) 2082 return 0; 2083 2084 p += strspn(p, delim); 2085 while (*p != '\0') { 2086 size_t len = strcspn(p, delim); 2087 char savech; 2088 2089 savech = p[len]; 2090 p[len] = '\0'; 2091 obj = load_object(p, -1, NULL, 0); 2092 if (obj == NULL) 2093 return -1; /* XXX - cleanup */ 2094 obj->z_interpose = true; 2095 p[len] = savech; 2096 p += len; 2097 p += strspn(p, delim); 2098 } 2099 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2100 return 0; 2101 } 2102 2103 static const char * 2104 printable_path(const char *path) 2105 { 2106 2107 return (path == NULL ? "<unknown>" : path); 2108 } 2109 2110 /* 2111 * Load a shared object into memory, if it is not already loaded. The 2112 * object may be specified by name or by user-supplied file descriptor 2113 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2114 * duplicate is. 2115 * 2116 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2117 * on failure. 2118 */ 2119 static Obj_Entry * 2120 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2121 { 2122 Obj_Entry *obj; 2123 int fd; 2124 struct stat sb; 2125 char *path; 2126 2127 fd = -1; 2128 if (name != NULL) { 2129 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 2130 if (object_match_name(obj, name)) 2131 return (obj); 2132 } 2133 2134 path = find_library(name, refobj, &fd); 2135 if (path == NULL) 2136 return (NULL); 2137 } else 2138 path = NULL; 2139 2140 if (fd >= 0) { 2141 /* 2142 * search_library_pathfds() opens a fresh file descriptor for the 2143 * library, so there is no need to dup(). 2144 */ 2145 } else if (fd_u == -1) { 2146 /* 2147 * If we didn't find a match by pathname, or the name is not 2148 * supplied, open the file and check again by device and inode. 2149 * This avoids false mismatches caused by multiple links or ".." 2150 * in pathnames. 2151 * 2152 * To avoid a race, we open the file and use fstat() rather than 2153 * using stat(). 2154 */ 2155 if ((fd = open(path, O_RDONLY | O_CLOEXEC)) == -1) { 2156 _rtld_error("Cannot open \"%s\"", path); 2157 free(path); 2158 return (NULL); 2159 } 2160 } else { 2161 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2162 if (fd == -1) { 2163 _rtld_error("Cannot dup fd"); 2164 free(path); 2165 return (NULL); 2166 } 2167 } 2168 if (fstat(fd, &sb) == -1) { 2169 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2170 close(fd); 2171 free(path); 2172 return NULL; 2173 } 2174 for (obj = obj_list->next; obj != NULL; obj = obj->next) 2175 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2176 break; 2177 if (obj != NULL && name != NULL) { 2178 object_add_name(obj, name); 2179 free(path); 2180 close(fd); 2181 return obj; 2182 } 2183 if (flags & RTLD_LO_NOLOAD) { 2184 free(path); 2185 close(fd); 2186 return (NULL); 2187 } 2188 2189 /* First use of this object, so we must map it in */ 2190 obj = do_load_object(fd, name, path, &sb, flags); 2191 if (obj == NULL) 2192 free(path); 2193 close(fd); 2194 2195 return obj; 2196 } 2197 2198 static Obj_Entry * 2199 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2200 int flags) 2201 { 2202 Obj_Entry *obj; 2203 struct statfs fs; 2204 2205 /* 2206 * but first, make sure that environment variables haven't been 2207 * used to circumvent the noexec flag on a filesystem. 2208 */ 2209 if (dangerous_ld_env) { 2210 if (fstatfs(fd, &fs) != 0) { 2211 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2212 return NULL; 2213 } 2214 if (fs.f_flags & MNT_NOEXEC) { 2215 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 2216 return NULL; 2217 } 2218 } 2219 dbg("loading \"%s\"", printable_path(path)); 2220 obj = map_object(fd, printable_path(path), sbp); 2221 if (obj == NULL) 2222 return NULL; 2223 2224 /* 2225 * If DT_SONAME is present in the object, digest_dynamic2 already 2226 * added it to the object names. 2227 */ 2228 if (name != NULL) 2229 object_add_name(obj, name); 2230 obj->path = path; 2231 digest_dynamic(obj, 0); 2232 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2233 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2234 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2235 RTLD_LO_DLOPEN) { 2236 dbg("refusing to load non-loadable \"%s\"", obj->path); 2237 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2238 munmap(obj->mapbase, obj->mapsize); 2239 obj_free(obj); 2240 return (NULL); 2241 } 2242 2243 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2244 *obj_tail = obj; 2245 obj_tail = &obj->next; 2246 obj_count++; 2247 obj_loads++; 2248 linkmap_add(obj); /* for GDB & dlinfo() */ 2249 max_stack_flags |= obj->stack_flags; 2250 2251 dbg(" %p .. %p: %s", obj->mapbase, 2252 obj->mapbase + obj->mapsize - 1, obj->path); 2253 if (obj->textrel) 2254 dbg(" WARNING: %s has impure text", obj->path); 2255 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2256 obj->path); 2257 2258 return obj; 2259 } 2260 2261 static Obj_Entry * 2262 obj_from_addr(const void *addr) 2263 { 2264 Obj_Entry *obj; 2265 2266 for (obj = obj_list; obj != NULL; obj = obj->next) { 2267 if (addr < (void *) obj->mapbase) 2268 continue; 2269 if (addr < (void *) (obj->mapbase + obj->mapsize)) 2270 return obj; 2271 } 2272 return NULL; 2273 } 2274 2275 static void 2276 preinit_main(void) 2277 { 2278 Elf_Addr *preinit_addr; 2279 int index; 2280 2281 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2282 if (preinit_addr == NULL) 2283 return; 2284 2285 for (index = 0; index < obj_main->preinit_array_num; index++) { 2286 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2287 dbg("calling preinit function for %s at %p", obj_main->path, 2288 (void *)preinit_addr[index]); 2289 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2290 0, 0, obj_main->path); 2291 call_init_pointer(obj_main, preinit_addr[index]); 2292 } 2293 } 2294 } 2295 2296 /* 2297 * Call the finalization functions for each of the objects in "list" 2298 * belonging to the DAG of "root" and referenced once. If NULL "root" 2299 * is specified, every finalization function will be called regardless 2300 * of the reference count and the list elements won't be freed. All of 2301 * the objects are expected to have non-NULL fini functions. 2302 */ 2303 static void 2304 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2305 { 2306 Objlist_Entry *elm; 2307 char *saved_msg; 2308 Elf_Addr *fini_addr; 2309 int index; 2310 2311 assert(root == NULL || root->refcount == 1); 2312 2313 /* 2314 * Preserve the current error message since a fini function might 2315 * call into the dynamic linker and overwrite it. 2316 */ 2317 saved_msg = errmsg_save(); 2318 do { 2319 STAILQ_FOREACH(elm, list, link) { 2320 if (root != NULL && (elm->obj->refcount != 1 || 2321 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2322 continue; 2323 /* Remove object from fini list to prevent recursive invocation. */ 2324 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2325 /* 2326 * XXX: If a dlopen() call references an object while the 2327 * fini function is in progress, we might end up trying to 2328 * unload the referenced object in dlclose() or the object 2329 * won't be unloaded although its fini function has been 2330 * called. 2331 */ 2332 lock_release(rtld_bind_lock, lockstate); 2333 2334 /* 2335 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2336 * When this happens, DT_FINI_ARRAY is processed first. 2337 */ 2338 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2339 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2340 for (index = elm->obj->fini_array_num - 1; index >= 0; 2341 index--) { 2342 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2343 dbg("calling fini function for %s at %p", 2344 elm->obj->path, (void *)fini_addr[index]); 2345 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2346 (void *)fini_addr[index], 0, 0, elm->obj->path); 2347 call_initfini_pointer(elm->obj, fini_addr[index]); 2348 } 2349 } 2350 } 2351 if (elm->obj->fini != (Elf_Addr)NULL) { 2352 dbg("calling fini function for %s at %p", elm->obj->path, 2353 (void *)elm->obj->fini); 2354 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2355 0, 0, elm->obj->path); 2356 call_initfini_pointer(elm->obj, elm->obj->fini); 2357 } 2358 wlock_acquire(rtld_bind_lock, lockstate); 2359 /* No need to free anything if process is going down. */ 2360 if (root != NULL) 2361 free(elm); 2362 /* 2363 * We must restart the list traversal after every fini call 2364 * because a dlclose() call from the fini function or from 2365 * another thread might have modified the reference counts. 2366 */ 2367 break; 2368 } 2369 } while (elm != NULL); 2370 errmsg_restore(saved_msg); 2371 } 2372 2373 /* 2374 * Call the initialization functions for each of the objects in 2375 * "list". All of the objects are expected to have non-NULL init 2376 * functions. 2377 */ 2378 static void 2379 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2380 { 2381 Objlist_Entry *elm; 2382 Obj_Entry *obj; 2383 char *saved_msg; 2384 Elf_Addr *init_addr; 2385 int index; 2386 2387 /* 2388 * Clean init_scanned flag so that objects can be rechecked and 2389 * possibly initialized earlier if any of vectors called below 2390 * cause the change by using dlopen. 2391 */ 2392 for (obj = obj_list; obj != NULL; obj = obj->next) 2393 obj->init_scanned = false; 2394 2395 /* 2396 * Preserve the current error message since an init function might 2397 * call into the dynamic linker and overwrite it. 2398 */ 2399 saved_msg = errmsg_save(); 2400 STAILQ_FOREACH(elm, list, link) { 2401 if (elm->obj->init_done) /* Initialized early. */ 2402 continue; 2403 /* 2404 * Race: other thread might try to use this object before current 2405 * one completes the initilization. Not much can be done here 2406 * without better locking. 2407 */ 2408 elm->obj->init_done = true; 2409 lock_release(rtld_bind_lock, lockstate); 2410 2411 /* 2412 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2413 * When this happens, DT_INIT is processed first. 2414 */ 2415 if (elm->obj->init != (Elf_Addr)NULL) { 2416 dbg("calling init function for %s at %p", elm->obj->path, 2417 (void *)elm->obj->init); 2418 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2419 0, 0, elm->obj->path); 2420 call_initfini_pointer(elm->obj, elm->obj->init); 2421 } 2422 init_addr = (Elf_Addr *)elm->obj->init_array; 2423 if (init_addr != NULL) { 2424 for (index = 0; index < elm->obj->init_array_num; index++) { 2425 if (init_addr[index] != 0 && init_addr[index] != 1) { 2426 dbg("calling init function for %s at %p", elm->obj->path, 2427 (void *)init_addr[index]); 2428 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2429 (void *)init_addr[index], 0, 0, elm->obj->path); 2430 call_init_pointer(elm->obj, init_addr[index]); 2431 } 2432 } 2433 } 2434 wlock_acquire(rtld_bind_lock, lockstate); 2435 } 2436 errmsg_restore(saved_msg); 2437 } 2438 2439 static void 2440 objlist_clear(Objlist *list) 2441 { 2442 Objlist_Entry *elm; 2443 2444 while (!STAILQ_EMPTY(list)) { 2445 elm = STAILQ_FIRST(list); 2446 STAILQ_REMOVE_HEAD(list, link); 2447 free(elm); 2448 } 2449 } 2450 2451 static Objlist_Entry * 2452 objlist_find(Objlist *list, const Obj_Entry *obj) 2453 { 2454 Objlist_Entry *elm; 2455 2456 STAILQ_FOREACH(elm, list, link) 2457 if (elm->obj == obj) 2458 return elm; 2459 return NULL; 2460 } 2461 2462 static void 2463 objlist_init(Objlist *list) 2464 { 2465 STAILQ_INIT(list); 2466 } 2467 2468 static void 2469 objlist_push_head(Objlist *list, Obj_Entry *obj) 2470 { 2471 Objlist_Entry *elm; 2472 2473 elm = NEW(Objlist_Entry); 2474 elm->obj = obj; 2475 STAILQ_INSERT_HEAD(list, elm, link); 2476 } 2477 2478 static void 2479 objlist_push_tail(Objlist *list, Obj_Entry *obj) 2480 { 2481 Objlist_Entry *elm; 2482 2483 elm = NEW(Objlist_Entry); 2484 elm->obj = obj; 2485 STAILQ_INSERT_TAIL(list, elm, link); 2486 } 2487 2488 static void 2489 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2490 { 2491 Objlist_Entry *elm, *listelm; 2492 2493 STAILQ_FOREACH(listelm, list, link) { 2494 if (listelm->obj == listobj) 2495 break; 2496 } 2497 elm = NEW(Objlist_Entry); 2498 elm->obj = obj; 2499 if (listelm != NULL) 2500 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2501 else 2502 STAILQ_INSERT_TAIL(list, elm, link); 2503 } 2504 2505 static void 2506 objlist_remove(Objlist *list, Obj_Entry *obj) 2507 { 2508 Objlist_Entry *elm; 2509 2510 if ((elm = objlist_find(list, obj)) != NULL) { 2511 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2512 free(elm); 2513 } 2514 } 2515 2516 /* 2517 * Relocate dag rooted in the specified object. 2518 * Returns 0 on success, or -1 on failure. 2519 */ 2520 2521 static int 2522 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2523 int flags, RtldLockState *lockstate) 2524 { 2525 Objlist_Entry *elm; 2526 int error; 2527 2528 error = 0; 2529 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2530 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2531 lockstate); 2532 if (error == -1) 2533 break; 2534 } 2535 return (error); 2536 } 2537 2538 /* 2539 * Relocate single object. 2540 * Returns 0 on success, or -1 on failure. 2541 */ 2542 static int 2543 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2544 int flags, RtldLockState *lockstate) 2545 { 2546 2547 if (obj->relocated) 2548 return (0); 2549 obj->relocated = true; 2550 if (obj != rtldobj) 2551 dbg("relocating \"%s\"", obj->path); 2552 2553 if (obj->symtab == NULL || obj->strtab == NULL || 2554 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2555 _rtld_error("%s: Shared object has no run-time symbol table", 2556 obj->path); 2557 return (-1); 2558 } 2559 2560 if (obj->textrel) { 2561 /* There are relocations to the write-protected text segment. */ 2562 if (mprotect(obj->mapbase, obj->textsize, 2563 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) { 2564 _rtld_error("%s: Cannot write-enable text segment: %s", 2565 obj->path, rtld_strerror(errno)); 2566 return (-1); 2567 } 2568 } 2569 2570 /* Process the non-PLT non-IFUNC relocations. */ 2571 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2572 return (-1); 2573 2574 if (obj->textrel) { /* Re-protected the text segment. */ 2575 if (mprotect(obj->mapbase, obj->textsize, 2576 PROT_READ|PROT_EXEC) == -1) { 2577 _rtld_error("%s: Cannot write-protect text segment: %s", 2578 obj->path, rtld_strerror(errno)); 2579 return (-1); 2580 } 2581 } 2582 2583 /* Set the special PLT or GOT entries. */ 2584 init_pltgot(obj); 2585 2586 /* Process the PLT relocations. */ 2587 if (reloc_plt(obj) == -1) 2588 return (-1); 2589 /* Relocate the jump slots if we are doing immediate binding. */ 2590 if (obj->bind_now || bind_now) 2591 if (reloc_jmpslots(obj, flags, lockstate) == -1) 2592 return (-1); 2593 2594 /* 2595 * Process the non-PLT IFUNC relocations. The relocations are 2596 * processed in two phases, because IFUNC resolvers may 2597 * reference other symbols, which must be readily processed 2598 * before resolvers are called. 2599 */ 2600 if (obj->non_plt_gnu_ifunc && 2601 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate)) 2602 return (-1); 2603 2604 if (obj->relro_size > 0) { 2605 if (mprotect(obj->relro_page, obj->relro_size, 2606 PROT_READ) == -1) { 2607 _rtld_error("%s: Cannot enforce relro protection: %s", 2608 obj->path, rtld_strerror(errno)); 2609 return (-1); 2610 } 2611 } 2612 2613 /* 2614 * Set up the magic number and version in the Obj_Entry. These 2615 * were checked in the crt1.o from the original ElfKit, so we 2616 * set them for backward compatibility. 2617 */ 2618 obj->magic = RTLD_MAGIC; 2619 obj->version = RTLD_VERSION; 2620 2621 return (0); 2622 } 2623 2624 /* 2625 * Relocate newly-loaded shared objects. The argument is a pointer to 2626 * the Obj_Entry for the first such object. All objects from the first 2627 * to the end of the list of objects are relocated. Returns 0 on success, 2628 * or -1 on failure. 2629 */ 2630 static int 2631 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2632 int flags, RtldLockState *lockstate) 2633 { 2634 Obj_Entry *obj; 2635 int error; 2636 2637 for (error = 0, obj = first; obj != NULL; obj = obj->next) { 2638 error = relocate_object(obj, bind_now, rtldobj, flags, 2639 lockstate); 2640 if (error == -1) 2641 break; 2642 } 2643 return (error); 2644 } 2645 2646 /* 2647 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2648 * referencing STT_GNU_IFUNC symbols is postponed till the other 2649 * relocations are done. The indirect functions specified as 2650 * ifunc are allowed to call other symbols, so we need to have 2651 * objects relocated before asking for resolution from indirects. 2652 * 2653 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2654 * instead of the usual lazy handling of PLT slots. It is 2655 * consistent with how GNU does it. 2656 */ 2657 static int 2658 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2659 RtldLockState *lockstate) 2660 { 2661 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2662 return (-1); 2663 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2664 reloc_gnu_ifunc(obj, flags, lockstate) == -1) 2665 return (-1); 2666 return (0); 2667 } 2668 2669 static int 2670 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags, 2671 RtldLockState *lockstate) 2672 { 2673 Obj_Entry *obj; 2674 2675 for (obj = first; obj != NULL; obj = obj->next) { 2676 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1) 2677 return (-1); 2678 } 2679 return (0); 2680 } 2681 2682 static int 2683 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2684 RtldLockState *lockstate) 2685 { 2686 Objlist_Entry *elm; 2687 2688 STAILQ_FOREACH(elm, list, link) { 2689 if (resolve_object_ifunc(elm->obj, bind_now, flags, 2690 lockstate) == -1) 2691 return (-1); 2692 } 2693 return (0); 2694 } 2695 2696 /* 2697 * Cleanup procedure. It will be called (by the atexit mechanism) just 2698 * before the process exits. 2699 */ 2700 static void 2701 rtld_exit(void) 2702 { 2703 RtldLockState lockstate; 2704 2705 wlock_acquire(rtld_bind_lock, &lockstate); 2706 dbg("rtld_exit()"); 2707 objlist_call_fini(&list_fini, NULL, &lockstate); 2708 /* No need to remove the items from the list, since we are exiting. */ 2709 if (!libmap_disable) 2710 lm_fini(); 2711 lock_release(rtld_bind_lock, &lockstate); 2712 } 2713 2714 /* 2715 * Iterate over a search path, translate each element, and invoke the 2716 * callback on the result. 2717 */ 2718 static void * 2719 path_enumerate(const char *path, path_enum_proc callback, void *arg) 2720 { 2721 const char *trans; 2722 if (path == NULL) 2723 return (NULL); 2724 2725 path += strspn(path, ":;"); 2726 while (*path != '\0') { 2727 size_t len; 2728 char *res; 2729 2730 len = strcspn(path, ":;"); 2731 trans = lm_findn(NULL, path, len); 2732 if (trans) 2733 res = callback(trans, strlen(trans), arg); 2734 else 2735 res = callback(path, len, arg); 2736 2737 if (res != NULL) 2738 return (res); 2739 2740 path += len; 2741 path += strspn(path, ":;"); 2742 } 2743 2744 return (NULL); 2745 } 2746 2747 struct try_library_args { 2748 const char *name; 2749 size_t namelen; 2750 char *buffer; 2751 size_t buflen; 2752 }; 2753 2754 static void * 2755 try_library_path(const char *dir, size_t dirlen, void *param) 2756 { 2757 struct try_library_args *arg; 2758 2759 arg = param; 2760 if (*dir == '/' || trust) { 2761 char *pathname; 2762 2763 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 2764 return (NULL); 2765 2766 pathname = arg->buffer; 2767 strncpy(pathname, dir, dirlen); 2768 pathname[dirlen] = '/'; 2769 strcpy(pathname + dirlen + 1, arg->name); 2770 2771 dbg(" Trying \"%s\"", pathname); 2772 if (access(pathname, F_OK) == 0) { /* We found it */ 2773 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 2774 strcpy(pathname, arg->buffer); 2775 return (pathname); 2776 } 2777 } 2778 return (NULL); 2779 } 2780 2781 static char * 2782 search_library_path(const char *name, const char *path) 2783 { 2784 char *p; 2785 struct try_library_args arg; 2786 2787 if (path == NULL) 2788 return NULL; 2789 2790 arg.name = name; 2791 arg.namelen = strlen(name); 2792 arg.buffer = xmalloc(PATH_MAX); 2793 arg.buflen = PATH_MAX; 2794 2795 p = path_enumerate(path, try_library_path, &arg); 2796 2797 free(arg.buffer); 2798 2799 return (p); 2800 } 2801 2802 2803 /* 2804 * Finds the library with the given name using the directory descriptors 2805 * listed in the LD_LIBRARY_PATH_FDS environment variable. 2806 * 2807 * Returns a freshly-opened close-on-exec file descriptor for the library, 2808 * or -1 if the library cannot be found. 2809 */ 2810 static char * 2811 search_library_pathfds(const char *name, const char *path, int *fdp) 2812 { 2813 char *envcopy, *fdstr, *found, *last_token; 2814 size_t len; 2815 int dirfd, fd; 2816 2817 dbg("%s('%s', '%s', fdp)", __func__, name, path); 2818 2819 /* Don't load from user-specified libdirs into setuid binaries. */ 2820 if (!trust) 2821 return (NULL); 2822 2823 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 2824 if (path == NULL) 2825 return (NULL); 2826 2827 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 2828 if (name[0] == '/') { 2829 dbg("Absolute path (%s) passed to %s", name, __func__); 2830 return (NULL); 2831 } 2832 2833 /* 2834 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 2835 * copy of the path, as strtok_r rewrites separator tokens 2836 * with '\0'. 2837 */ 2838 found = NULL; 2839 envcopy = xstrdup(path); 2840 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 2841 fdstr = strtok_r(NULL, ":", &last_token)) { 2842 dirfd = parse_libdir(fdstr); 2843 if (dirfd < 0) 2844 break; 2845 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC); 2846 if (fd >= 0) { 2847 *fdp = fd; 2848 len = strlen(fdstr) + strlen(name) + 3; 2849 found = xmalloc(len); 2850 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 2851 _rtld_error("error generating '%d/%s'", 2852 dirfd, name); 2853 rtld_die(); 2854 } 2855 dbg("open('%s') => %d", found, fd); 2856 break; 2857 } 2858 } 2859 free(envcopy); 2860 2861 return (found); 2862 } 2863 2864 2865 int 2866 dlclose(void *handle) 2867 { 2868 Obj_Entry *root; 2869 RtldLockState lockstate; 2870 2871 wlock_acquire(rtld_bind_lock, &lockstate); 2872 root = dlcheck(handle); 2873 if (root == NULL) { 2874 lock_release(rtld_bind_lock, &lockstate); 2875 return -1; 2876 } 2877 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 2878 root->path); 2879 2880 /* Unreference the object and its dependencies. */ 2881 root->dl_refcount--; 2882 2883 if (root->refcount == 1) { 2884 /* 2885 * The object will be no longer referenced, so we must unload it. 2886 * First, call the fini functions. 2887 */ 2888 objlist_call_fini(&list_fini, root, &lockstate); 2889 2890 unref_dag(root); 2891 2892 /* Finish cleaning up the newly-unreferenced objects. */ 2893 GDB_STATE(RT_DELETE,&root->linkmap); 2894 unload_object(root); 2895 GDB_STATE(RT_CONSISTENT,NULL); 2896 } else 2897 unref_dag(root); 2898 2899 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 2900 lock_release(rtld_bind_lock, &lockstate); 2901 return 0; 2902 } 2903 2904 char * 2905 dlerror(void) 2906 { 2907 char *msg = error_message; 2908 error_message = NULL; 2909 return msg; 2910 } 2911 2912 /* 2913 * This function is deprecated and has no effect. 2914 */ 2915 void 2916 dllockinit(void *context, 2917 void *(*lock_create)(void *context), 2918 void (*rlock_acquire)(void *lock), 2919 void (*wlock_acquire)(void *lock), 2920 void (*lock_release)(void *lock), 2921 void (*lock_destroy)(void *lock), 2922 void (*context_destroy)(void *context)) 2923 { 2924 static void *cur_context; 2925 static void (*cur_context_destroy)(void *); 2926 2927 /* Just destroy the context from the previous call, if necessary. */ 2928 if (cur_context_destroy != NULL) 2929 cur_context_destroy(cur_context); 2930 cur_context = context; 2931 cur_context_destroy = context_destroy; 2932 } 2933 2934 void * 2935 dlopen(const char *name, int mode) 2936 { 2937 2938 return (rtld_dlopen(name, -1, mode)); 2939 } 2940 2941 void * 2942 fdlopen(int fd, int mode) 2943 { 2944 2945 return (rtld_dlopen(NULL, fd, mode)); 2946 } 2947 2948 static void * 2949 rtld_dlopen(const char *name, int fd, int mode) 2950 { 2951 RtldLockState lockstate; 2952 int lo_flags; 2953 2954 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 2955 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 2956 if (ld_tracing != NULL) { 2957 rlock_acquire(rtld_bind_lock, &lockstate); 2958 if (sigsetjmp(lockstate.env, 0) != 0) 2959 lock_upgrade(rtld_bind_lock, &lockstate); 2960 environ = (char **)*get_program_var_addr("environ", &lockstate); 2961 lock_release(rtld_bind_lock, &lockstate); 2962 } 2963 lo_flags = RTLD_LO_DLOPEN; 2964 if (mode & RTLD_NODELETE) 2965 lo_flags |= RTLD_LO_NODELETE; 2966 if (mode & RTLD_NOLOAD) 2967 lo_flags |= RTLD_LO_NOLOAD; 2968 if (ld_tracing != NULL) 2969 lo_flags |= RTLD_LO_TRACE; 2970 2971 return (dlopen_object(name, fd, obj_main, lo_flags, 2972 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 2973 } 2974 2975 static void 2976 dlopen_cleanup(Obj_Entry *obj) 2977 { 2978 2979 obj->dl_refcount--; 2980 unref_dag(obj); 2981 if (obj->refcount == 0) 2982 unload_object(obj); 2983 } 2984 2985 static Obj_Entry * 2986 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 2987 int mode, RtldLockState *lockstate) 2988 { 2989 Obj_Entry **old_obj_tail; 2990 Obj_Entry *obj; 2991 Objlist initlist; 2992 RtldLockState mlockstate; 2993 int result; 2994 2995 objlist_init(&initlist); 2996 2997 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 2998 wlock_acquire(rtld_bind_lock, &mlockstate); 2999 lockstate = &mlockstate; 3000 } 3001 GDB_STATE(RT_ADD,NULL); 3002 3003 old_obj_tail = obj_tail; 3004 obj = NULL; 3005 if (name == NULL && fd == -1) { 3006 obj = obj_main; 3007 obj->refcount++; 3008 } else { 3009 obj = load_object(name, fd, refobj, lo_flags); 3010 } 3011 3012 if (obj) { 3013 obj->dl_refcount++; 3014 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3015 objlist_push_tail(&list_global, obj); 3016 if (*old_obj_tail != NULL) { /* We loaded something new. */ 3017 assert(*old_obj_tail == obj); 3018 result = load_needed_objects(obj, 3019 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 3020 init_dag(obj); 3021 ref_dag(obj); 3022 if (result != -1) 3023 result = rtld_verify_versions(&obj->dagmembers); 3024 if (result != -1 && ld_tracing) 3025 goto trace; 3026 if (result == -1 || relocate_object_dag(obj, 3027 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3028 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3029 lockstate) == -1) { 3030 dlopen_cleanup(obj); 3031 obj = NULL; 3032 } else if (lo_flags & RTLD_LO_EARLY) { 3033 /* 3034 * Do not call the init functions for early loaded 3035 * filtees. The image is still not initialized enough 3036 * for them to work. 3037 * 3038 * Our object is found by the global object list and 3039 * will be ordered among all init calls done right 3040 * before transferring control to main. 3041 */ 3042 } else { 3043 /* Make list of init functions to call. */ 3044 initlist_add_objects(obj, &obj->next, &initlist); 3045 } 3046 /* 3047 * Process all no_delete objects here, given them own 3048 * DAGs to prevent their dependencies from being unloaded. 3049 * This has to be done after we have loaded all of the 3050 * dependencies, so that we do not miss any. 3051 */ 3052 if (obj != NULL) 3053 process_nodelete(obj); 3054 } else { 3055 /* 3056 * Bump the reference counts for objects on this DAG. If 3057 * this is the first dlopen() call for the object that was 3058 * already loaded as a dependency, initialize the dag 3059 * starting at it. 3060 */ 3061 init_dag(obj); 3062 ref_dag(obj); 3063 3064 if ((lo_flags & RTLD_LO_TRACE) != 0) 3065 goto trace; 3066 } 3067 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3068 obj->z_nodelete) && !obj->ref_nodel) { 3069 dbg("obj %s nodelete", obj->path); 3070 ref_dag(obj); 3071 obj->z_nodelete = obj->ref_nodel = true; 3072 } 3073 } 3074 3075 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3076 name); 3077 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3078 3079 if (!(lo_flags & RTLD_LO_EARLY)) { 3080 map_stacks_exec(lockstate); 3081 } 3082 3083 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3084 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3085 lockstate) == -1) { 3086 objlist_clear(&initlist); 3087 dlopen_cleanup(obj); 3088 if (lockstate == &mlockstate) 3089 lock_release(rtld_bind_lock, lockstate); 3090 return (NULL); 3091 } 3092 3093 if (!(lo_flags & RTLD_LO_EARLY)) { 3094 /* Call the init functions. */ 3095 objlist_call_init(&initlist, lockstate); 3096 } 3097 objlist_clear(&initlist); 3098 if (lockstate == &mlockstate) 3099 lock_release(rtld_bind_lock, lockstate); 3100 return obj; 3101 trace: 3102 trace_loaded_objects(obj); 3103 if (lockstate == &mlockstate) 3104 lock_release(rtld_bind_lock, lockstate); 3105 exit(0); 3106 } 3107 3108 static void * 3109 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3110 int flags) 3111 { 3112 DoneList donelist; 3113 const Obj_Entry *obj, *defobj; 3114 const Elf_Sym *def; 3115 SymLook req; 3116 RtldLockState lockstate; 3117 tls_index ti; 3118 void *sym; 3119 int res; 3120 3121 def = NULL; 3122 defobj = NULL; 3123 symlook_init(&req, name); 3124 req.ventry = ve; 3125 req.flags = flags | SYMLOOK_IN_PLT; 3126 req.lockstate = &lockstate; 3127 3128 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3129 rlock_acquire(rtld_bind_lock, &lockstate); 3130 if (sigsetjmp(lockstate.env, 0) != 0) 3131 lock_upgrade(rtld_bind_lock, &lockstate); 3132 if (handle == NULL || handle == RTLD_NEXT || 3133 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3134 3135 if ((obj = obj_from_addr(retaddr)) == NULL) { 3136 _rtld_error("Cannot determine caller's shared object"); 3137 lock_release(rtld_bind_lock, &lockstate); 3138 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3139 return NULL; 3140 } 3141 if (handle == NULL) { /* Just the caller's shared object. */ 3142 res = symlook_obj(&req, obj); 3143 if (res == 0) { 3144 def = req.sym_out; 3145 defobj = req.defobj_out; 3146 } 3147 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3148 handle == RTLD_SELF) { /* ... caller included */ 3149 if (handle == RTLD_NEXT) 3150 obj = obj->next; 3151 for (; obj != NULL; obj = obj->next) { 3152 res = symlook_obj(&req, obj); 3153 if (res == 0) { 3154 if (def == NULL || 3155 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3156 def = req.sym_out; 3157 defobj = req.defobj_out; 3158 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3159 break; 3160 } 3161 } 3162 } 3163 /* 3164 * Search the dynamic linker itself, and possibly resolve the 3165 * symbol from there. This is how the application links to 3166 * dynamic linker services such as dlopen. 3167 */ 3168 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3169 res = symlook_obj(&req, &obj_rtld); 3170 if (res == 0) { 3171 def = req.sym_out; 3172 defobj = req.defobj_out; 3173 } 3174 } 3175 } else { 3176 assert(handle == RTLD_DEFAULT); 3177 res = symlook_default(&req, obj); 3178 if (res == 0) { 3179 defobj = req.defobj_out; 3180 def = req.sym_out; 3181 } 3182 } 3183 } else { 3184 if ((obj = dlcheck(handle)) == NULL) { 3185 lock_release(rtld_bind_lock, &lockstate); 3186 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3187 return NULL; 3188 } 3189 3190 donelist_init(&donelist); 3191 if (obj->mainprog) { 3192 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3193 res = symlook_global(&req, &donelist); 3194 if (res == 0) { 3195 def = req.sym_out; 3196 defobj = req.defobj_out; 3197 } 3198 /* 3199 * Search the dynamic linker itself, and possibly resolve the 3200 * symbol from there. This is how the application links to 3201 * dynamic linker services such as dlopen. 3202 */ 3203 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3204 res = symlook_obj(&req, &obj_rtld); 3205 if (res == 0) { 3206 def = req.sym_out; 3207 defobj = req.defobj_out; 3208 } 3209 } 3210 } 3211 else { 3212 /* Search the whole DAG rooted at the given object. */ 3213 res = symlook_list(&req, &obj->dagmembers, &donelist); 3214 if (res == 0) { 3215 def = req.sym_out; 3216 defobj = req.defobj_out; 3217 } 3218 } 3219 } 3220 3221 if (def != NULL) { 3222 lock_release(rtld_bind_lock, &lockstate); 3223 3224 /* 3225 * The value required by the caller is derived from the value 3226 * of the symbol. this is simply the relocated value of the 3227 * symbol. 3228 */ 3229 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3230 sym = make_function_pointer(def, defobj); 3231 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3232 sym = rtld_resolve_ifunc(defobj, def); 3233 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3234 ti.ti_module = defobj->tlsindex; 3235 ti.ti_offset = def->st_value; 3236 sym = __tls_get_addr(&ti); 3237 } else 3238 sym = defobj->relocbase + def->st_value; 3239 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3240 return (sym); 3241 } 3242 3243 _rtld_error("Undefined symbol \"%s\"", name); 3244 lock_release(rtld_bind_lock, &lockstate); 3245 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3246 return NULL; 3247 } 3248 3249 void * 3250 dlsym(void *handle, const char *name) 3251 { 3252 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3253 SYMLOOK_DLSYM); 3254 } 3255 3256 dlfunc_t 3257 dlfunc(void *handle, const char *name) 3258 { 3259 union { 3260 void *d; 3261 dlfunc_t f; 3262 } rv; 3263 3264 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3265 SYMLOOK_DLSYM); 3266 return (rv.f); 3267 } 3268 3269 void * 3270 dlvsym(void *handle, const char *name, const char *version) 3271 { 3272 Ver_Entry ventry; 3273 3274 ventry.name = version; 3275 ventry.file = NULL; 3276 ventry.hash = elf_hash(version); 3277 ventry.flags= 0; 3278 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3279 SYMLOOK_DLSYM); 3280 } 3281 3282 int 3283 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3284 { 3285 const Obj_Entry *obj; 3286 RtldLockState lockstate; 3287 3288 rlock_acquire(rtld_bind_lock, &lockstate); 3289 obj = obj_from_addr(addr); 3290 if (obj == NULL) { 3291 _rtld_error("No shared object contains address"); 3292 lock_release(rtld_bind_lock, &lockstate); 3293 return (0); 3294 } 3295 rtld_fill_dl_phdr_info(obj, phdr_info); 3296 lock_release(rtld_bind_lock, &lockstate); 3297 return (1); 3298 } 3299 3300 int 3301 dladdr(const void *addr, Dl_info *info) 3302 { 3303 const Obj_Entry *obj; 3304 const Elf_Sym *def; 3305 void *symbol_addr; 3306 unsigned long symoffset; 3307 RtldLockState lockstate; 3308 3309 rlock_acquire(rtld_bind_lock, &lockstate); 3310 obj = obj_from_addr(addr); 3311 if (obj == NULL) { 3312 _rtld_error("No shared object contains address"); 3313 lock_release(rtld_bind_lock, &lockstate); 3314 return 0; 3315 } 3316 info->dli_fname = obj->path; 3317 info->dli_fbase = obj->mapbase; 3318 info->dli_saddr = (void *)0; 3319 info->dli_sname = NULL; 3320 3321 /* 3322 * Walk the symbol list looking for the symbol whose address is 3323 * closest to the address sent in. 3324 */ 3325 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3326 def = obj->symtab + symoffset; 3327 3328 /* 3329 * For skip the symbol if st_shndx is either SHN_UNDEF or 3330 * SHN_COMMON. 3331 */ 3332 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3333 continue; 3334 3335 /* 3336 * If the symbol is greater than the specified address, or if it 3337 * is further away from addr than the current nearest symbol, 3338 * then reject it. 3339 */ 3340 symbol_addr = obj->relocbase + def->st_value; 3341 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3342 continue; 3343 3344 /* Update our idea of the nearest symbol. */ 3345 info->dli_sname = obj->strtab + def->st_name; 3346 info->dli_saddr = symbol_addr; 3347 3348 /* Exact match? */ 3349 if (info->dli_saddr == addr) 3350 break; 3351 } 3352 lock_release(rtld_bind_lock, &lockstate); 3353 return 1; 3354 } 3355 3356 int 3357 dlinfo(void *handle, int request, void *p) 3358 { 3359 const Obj_Entry *obj; 3360 RtldLockState lockstate; 3361 int error; 3362 3363 rlock_acquire(rtld_bind_lock, &lockstate); 3364 3365 if (handle == NULL || handle == RTLD_SELF) { 3366 void *retaddr; 3367 3368 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3369 if ((obj = obj_from_addr(retaddr)) == NULL) 3370 _rtld_error("Cannot determine caller's shared object"); 3371 } else 3372 obj = dlcheck(handle); 3373 3374 if (obj == NULL) { 3375 lock_release(rtld_bind_lock, &lockstate); 3376 return (-1); 3377 } 3378 3379 error = 0; 3380 switch (request) { 3381 case RTLD_DI_LINKMAP: 3382 *((struct link_map const **)p) = &obj->linkmap; 3383 break; 3384 case RTLD_DI_ORIGIN: 3385 error = rtld_dirname(obj->path, p); 3386 break; 3387 3388 case RTLD_DI_SERINFOSIZE: 3389 case RTLD_DI_SERINFO: 3390 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3391 break; 3392 3393 default: 3394 _rtld_error("Invalid request %d passed to dlinfo()", request); 3395 error = -1; 3396 } 3397 3398 lock_release(rtld_bind_lock, &lockstate); 3399 3400 return (error); 3401 } 3402 3403 static void 3404 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3405 { 3406 3407 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3408 phdr_info->dlpi_name = obj->path; 3409 phdr_info->dlpi_phdr = obj->phdr; 3410 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3411 phdr_info->dlpi_tls_modid = obj->tlsindex; 3412 phdr_info->dlpi_tls_data = obj->tlsinit; 3413 phdr_info->dlpi_adds = obj_loads; 3414 phdr_info->dlpi_subs = obj_loads - obj_count; 3415 } 3416 3417 int 3418 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3419 { 3420 struct dl_phdr_info phdr_info; 3421 const Obj_Entry *obj; 3422 RtldLockState bind_lockstate, phdr_lockstate; 3423 int error; 3424 3425 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3426 rlock_acquire(rtld_bind_lock, &bind_lockstate); 3427 3428 error = 0; 3429 3430 for (obj = obj_list; obj != NULL; obj = obj->next) { 3431 rtld_fill_dl_phdr_info(obj, &phdr_info); 3432 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0) 3433 break; 3434 3435 } 3436 if (error == 0) { 3437 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3438 error = callback(&phdr_info, sizeof(phdr_info), param); 3439 } 3440 3441 lock_release(rtld_bind_lock, &bind_lockstate); 3442 lock_release(rtld_phdr_lock, &phdr_lockstate); 3443 3444 return (error); 3445 } 3446 3447 static void * 3448 fill_search_info(const char *dir, size_t dirlen, void *param) 3449 { 3450 struct fill_search_info_args *arg; 3451 3452 arg = param; 3453 3454 if (arg->request == RTLD_DI_SERINFOSIZE) { 3455 arg->serinfo->dls_cnt ++; 3456 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3457 } else { 3458 struct dl_serpath *s_entry; 3459 3460 s_entry = arg->serpath; 3461 s_entry->dls_name = arg->strspace; 3462 s_entry->dls_flags = arg->flags; 3463 3464 strncpy(arg->strspace, dir, dirlen); 3465 arg->strspace[dirlen] = '\0'; 3466 3467 arg->strspace += dirlen + 1; 3468 arg->serpath++; 3469 } 3470 3471 return (NULL); 3472 } 3473 3474 static int 3475 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3476 { 3477 struct dl_serinfo _info; 3478 struct fill_search_info_args args; 3479 3480 args.request = RTLD_DI_SERINFOSIZE; 3481 args.serinfo = &_info; 3482 3483 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3484 _info.dls_cnt = 0; 3485 3486 path_enumerate(obj->rpath, fill_search_info, &args); 3487 path_enumerate(ld_library_path, fill_search_info, &args); 3488 path_enumerate(obj->runpath, fill_search_info, &args); 3489 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args); 3490 if (!obj->z_nodeflib) 3491 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 3492 3493 3494 if (request == RTLD_DI_SERINFOSIZE) { 3495 info->dls_size = _info.dls_size; 3496 info->dls_cnt = _info.dls_cnt; 3497 return (0); 3498 } 3499 3500 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3501 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3502 return (-1); 3503 } 3504 3505 args.request = RTLD_DI_SERINFO; 3506 args.serinfo = info; 3507 args.serpath = &info->dls_serpath[0]; 3508 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3509 3510 args.flags = LA_SER_RUNPATH; 3511 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 3512 return (-1); 3513 3514 args.flags = LA_SER_LIBPATH; 3515 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 3516 return (-1); 3517 3518 args.flags = LA_SER_RUNPATH; 3519 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL) 3520 return (-1); 3521 3522 args.flags = LA_SER_CONFIG; 3523 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args) 3524 != NULL) 3525 return (-1); 3526 3527 args.flags = LA_SER_DEFAULT; 3528 if (!obj->z_nodeflib && 3529 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 3530 return (-1); 3531 return (0); 3532 } 3533 3534 static int 3535 rtld_dirname(const char *path, char *bname) 3536 { 3537 const char *endp; 3538 3539 /* Empty or NULL string gets treated as "." */ 3540 if (path == NULL || *path == '\0') { 3541 bname[0] = '.'; 3542 bname[1] = '\0'; 3543 return (0); 3544 } 3545 3546 /* Strip trailing slashes */ 3547 endp = path + strlen(path) - 1; 3548 while (endp > path && *endp == '/') 3549 endp--; 3550 3551 /* Find the start of the dir */ 3552 while (endp > path && *endp != '/') 3553 endp--; 3554 3555 /* Either the dir is "/" or there are no slashes */ 3556 if (endp == path) { 3557 bname[0] = *endp == '/' ? '/' : '.'; 3558 bname[1] = '\0'; 3559 return (0); 3560 } else { 3561 do { 3562 endp--; 3563 } while (endp > path && *endp == '/'); 3564 } 3565 3566 if (endp - path + 2 > PATH_MAX) 3567 { 3568 _rtld_error("Filename is too long: %s", path); 3569 return(-1); 3570 } 3571 3572 strncpy(bname, path, endp - path + 1); 3573 bname[endp - path + 1] = '\0'; 3574 return (0); 3575 } 3576 3577 static int 3578 rtld_dirname_abs(const char *path, char *base) 3579 { 3580 char *last; 3581 3582 if (realpath(path, base) == NULL) 3583 return (-1); 3584 dbg("%s -> %s", path, base); 3585 last = strrchr(base, '/'); 3586 if (last == NULL) 3587 return (-1); 3588 if (last != base) 3589 *last = '\0'; 3590 return (0); 3591 } 3592 3593 static void 3594 linkmap_add(Obj_Entry *obj) 3595 { 3596 struct link_map *l = &obj->linkmap; 3597 struct link_map *prev; 3598 3599 obj->linkmap.l_name = obj->path; 3600 obj->linkmap.l_addr = obj->mapbase; 3601 obj->linkmap.l_ld = obj->dynamic; 3602 #ifdef __mips__ 3603 /* GDB needs load offset on MIPS to use the symbols */ 3604 obj->linkmap.l_offs = obj->relocbase; 3605 #endif 3606 3607 if (r_debug.r_map == NULL) { 3608 r_debug.r_map = l; 3609 return; 3610 } 3611 3612 /* 3613 * Scan to the end of the list, but not past the entry for the 3614 * dynamic linker, which we want to keep at the very end. 3615 */ 3616 for (prev = r_debug.r_map; 3617 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3618 prev = prev->l_next) 3619 ; 3620 3621 /* Link in the new entry. */ 3622 l->l_prev = prev; 3623 l->l_next = prev->l_next; 3624 if (l->l_next != NULL) 3625 l->l_next->l_prev = l; 3626 prev->l_next = l; 3627 } 3628 3629 static void 3630 linkmap_delete(Obj_Entry *obj) 3631 { 3632 struct link_map *l = &obj->linkmap; 3633 3634 if (l->l_prev == NULL) { 3635 if ((r_debug.r_map = l->l_next) != NULL) 3636 l->l_next->l_prev = NULL; 3637 return; 3638 } 3639 3640 if ((l->l_prev->l_next = l->l_next) != NULL) 3641 l->l_next->l_prev = l->l_prev; 3642 } 3643 3644 /* 3645 * Function for the debugger to set a breakpoint on to gain control. 3646 * 3647 * The two parameters allow the debugger to easily find and determine 3648 * what the runtime loader is doing and to whom it is doing it. 3649 * 3650 * When the loadhook trap is hit (r_debug_state, set at program 3651 * initialization), the arguments can be found on the stack: 3652 * 3653 * +8 struct link_map *m 3654 * +4 struct r_debug *rd 3655 * +0 RetAddr 3656 */ 3657 void 3658 r_debug_state(struct r_debug* rd, struct link_map *m) 3659 { 3660 /* 3661 * The following is a hack to force the compiler to emit calls to 3662 * this function, even when optimizing. If the function is empty, 3663 * the compiler is not obliged to emit any code for calls to it, 3664 * even when marked __noinline. However, gdb depends on those 3665 * calls being made. 3666 */ 3667 __compiler_membar(); 3668 } 3669 3670 /* 3671 * A function called after init routines have completed. This can be used to 3672 * break before a program's entry routine is called, and can be used when 3673 * main is not available in the symbol table. 3674 */ 3675 void 3676 _r_debug_postinit(struct link_map *m) 3677 { 3678 3679 /* See r_debug_state(). */ 3680 __compiler_membar(); 3681 } 3682 3683 /* 3684 * Get address of the pointer variable in the main program. 3685 * Prefer non-weak symbol over the weak one. 3686 */ 3687 static const void ** 3688 get_program_var_addr(const char *name, RtldLockState *lockstate) 3689 { 3690 SymLook req; 3691 DoneList donelist; 3692 3693 symlook_init(&req, name); 3694 req.lockstate = lockstate; 3695 donelist_init(&donelist); 3696 if (symlook_global(&req, &donelist) != 0) 3697 return (NULL); 3698 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 3699 return ((const void **)make_function_pointer(req.sym_out, 3700 req.defobj_out)); 3701 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 3702 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 3703 else 3704 return ((const void **)(req.defobj_out->relocbase + 3705 req.sym_out->st_value)); 3706 } 3707 3708 /* 3709 * Set a pointer variable in the main program to the given value. This 3710 * is used to set key variables such as "environ" before any of the 3711 * init functions are called. 3712 */ 3713 static void 3714 set_program_var(const char *name, const void *value) 3715 { 3716 const void **addr; 3717 3718 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 3719 dbg("\"%s\": *%p <-- %p", name, addr, value); 3720 *addr = value; 3721 } 3722 } 3723 3724 /* 3725 * Search the global objects, including dependencies and main object, 3726 * for the given symbol. 3727 */ 3728 static int 3729 symlook_global(SymLook *req, DoneList *donelist) 3730 { 3731 SymLook req1; 3732 const Objlist_Entry *elm; 3733 int res; 3734 3735 symlook_init_from_req(&req1, req); 3736 3737 /* Search all objects loaded at program start up. */ 3738 if (req->defobj_out == NULL || 3739 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3740 res = symlook_list(&req1, &list_main, donelist); 3741 if (res == 0 && (req->defobj_out == NULL || 3742 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3743 req->sym_out = req1.sym_out; 3744 req->defobj_out = req1.defobj_out; 3745 assert(req->defobj_out != NULL); 3746 } 3747 } 3748 3749 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 3750 STAILQ_FOREACH(elm, &list_global, link) { 3751 if (req->defobj_out != NULL && 3752 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3753 break; 3754 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 3755 if (res == 0 && (req->defobj_out == NULL || 3756 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3757 req->sym_out = req1.sym_out; 3758 req->defobj_out = req1.defobj_out; 3759 assert(req->defobj_out != NULL); 3760 } 3761 } 3762 3763 return (req->sym_out != NULL ? 0 : ESRCH); 3764 } 3765 3766 /* 3767 * Given a symbol name in a referencing object, find the corresponding 3768 * definition of the symbol. Returns a pointer to the symbol, or NULL if 3769 * no definition was found. Returns a pointer to the Obj_Entry of the 3770 * defining object via the reference parameter DEFOBJ_OUT. 3771 */ 3772 static int 3773 symlook_default(SymLook *req, const Obj_Entry *refobj) 3774 { 3775 DoneList donelist; 3776 const Objlist_Entry *elm; 3777 SymLook req1; 3778 int res; 3779 3780 donelist_init(&donelist); 3781 symlook_init_from_req(&req1, req); 3782 3783 /* Look first in the referencing object if linked symbolically. */ 3784 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 3785 res = symlook_obj(&req1, refobj); 3786 if (res == 0) { 3787 req->sym_out = req1.sym_out; 3788 req->defobj_out = req1.defobj_out; 3789 assert(req->defobj_out != NULL); 3790 } 3791 } 3792 3793 symlook_global(req, &donelist); 3794 3795 /* Search all dlopened DAGs containing the referencing object. */ 3796 STAILQ_FOREACH(elm, &refobj->dldags, link) { 3797 if (req->sym_out != NULL && 3798 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3799 break; 3800 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 3801 if (res == 0 && (req->sym_out == NULL || 3802 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3803 req->sym_out = req1.sym_out; 3804 req->defobj_out = req1.defobj_out; 3805 assert(req->defobj_out != NULL); 3806 } 3807 } 3808 3809 /* 3810 * Search the dynamic linker itself, and possibly resolve the 3811 * symbol from there. This is how the application links to 3812 * dynamic linker services such as dlopen. 3813 */ 3814 if (req->sym_out == NULL || 3815 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3816 res = symlook_obj(&req1, &obj_rtld); 3817 if (res == 0) { 3818 req->sym_out = req1.sym_out; 3819 req->defobj_out = req1.defobj_out; 3820 assert(req->defobj_out != NULL); 3821 } 3822 } 3823 3824 return (req->sym_out != NULL ? 0 : ESRCH); 3825 } 3826 3827 static int 3828 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 3829 { 3830 const Elf_Sym *def; 3831 const Obj_Entry *defobj; 3832 const Objlist_Entry *elm; 3833 SymLook req1; 3834 int res; 3835 3836 def = NULL; 3837 defobj = NULL; 3838 STAILQ_FOREACH(elm, objlist, link) { 3839 if (donelist_check(dlp, elm->obj)) 3840 continue; 3841 symlook_init_from_req(&req1, req); 3842 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 3843 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3844 def = req1.sym_out; 3845 defobj = req1.defobj_out; 3846 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3847 break; 3848 } 3849 } 3850 } 3851 if (def != NULL) { 3852 req->sym_out = def; 3853 req->defobj_out = defobj; 3854 return (0); 3855 } 3856 return (ESRCH); 3857 } 3858 3859 /* 3860 * Search the chain of DAGS cointed to by the given Needed_Entry 3861 * for a symbol of the given name. Each DAG is scanned completely 3862 * before advancing to the next one. Returns a pointer to the symbol, 3863 * or NULL if no definition was found. 3864 */ 3865 static int 3866 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 3867 { 3868 const Elf_Sym *def; 3869 const Needed_Entry *n; 3870 const Obj_Entry *defobj; 3871 SymLook req1; 3872 int res; 3873 3874 def = NULL; 3875 defobj = NULL; 3876 symlook_init_from_req(&req1, req); 3877 for (n = needed; n != NULL; n = n->next) { 3878 if (n->obj == NULL || 3879 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 3880 continue; 3881 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3882 def = req1.sym_out; 3883 defobj = req1.defobj_out; 3884 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3885 break; 3886 } 3887 } 3888 if (def != NULL) { 3889 req->sym_out = def; 3890 req->defobj_out = defobj; 3891 return (0); 3892 } 3893 return (ESRCH); 3894 } 3895 3896 /* 3897 * Search the symbol table of a single shared object for a symbol of 3898 * the given name and version, if requested. Returns a pointer to the 3899 * symbol, or NULL if no definition was found. If the object is 3900 * filter, return filtered symbol from filtee. 3901 * 3902 * The symbol's hash value is passed in for efficiency reasons; that 3903 * eliminates many recomputations of the hash value. 3904 */ 3905 int 3906 symlook_obj(SymLook *req, const Obj_Entry *obj) 3907 { 3908 DoneList donelist; 3909 SymLook req1; 3910 int flags, res, mres; 3911 3912 /* 3913 * If there is at least one valid hash at this point, we prefer to 3914 * use the faster GNU version if available. 3915 */ 3916 if (obj->valid_hash_gnu) 3917 mres = symlook_obj1_gnu(req, obj); 3918 else if (obj->valid_hash_sysv) 3919 mres = symlook_obj1_sysv(req, obj); 3920 else 3921 return (EINVAL); 3922 3923 if (mres == 0) { 3924 if (obj->needed_filtees != NULL) { 3925 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3926 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3927 donelist_init(&donelist); 3928 symlook_init_from_req(&req1, req); 3929 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 3930 if (res == 0) { 3931 req->sym_out = req1.sym_out; 3932 req->defobj_out = req1.defobj_out; 3933 } 3934 return (res); 3935 } 3936 if (obj->needed_aux_filtees != NULL) { 3937 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3938 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3939 donelist_init(&donelist); 3940 symlook_init_from_req(&req1, req); 3941 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 3942 if (res == 0) { 3943 req->sym_out = req1.sym_out; 3944 req->defobj_out = req1.defobj_out; 3945 return (res); 3946 } 3947 } 3948 } 3949 return (mres); 3950 } 3951 3952 /* Symbol match routine common to both hash functions */ 3953 static bool 3954 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 3955 const unsigned long symnum) 3956 { 3957 Elf_Versym verndx; 3958 const Elf_Sym *symp; 3959 const char *strp; 3960 3961 symp = obj->symtab + symnum; 3962 strp = obj->strtab + symp->st_name; 3963 3964 switch (ELF_ST_TYPE(symp->st_info)) { 3965 case STT_FUNC: 3966 case STT_NOTYPE: 3967 case STT_OBJECT: 3968 case STT_COMMON: 3969 case STT_GNU_IFUNC: 3970 if (symp->st_value == 0) 3971 return (false); 3972 /* fallthrough */ 3973 case STT_TLS: 3974 if (symp->st_shndx != SHN_UNDEF) 3975 break; 3976 #ifndef __mips__ 3977 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 3978 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 3979 break; 3980 /* fallthrough */ 3981 #endif 3982 default: 3983 return (false); 3984 } 3985 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 3986 return (false); 3987 3988 if (req->ventry == NULL) { 3989 if (obj->versyms != NULL) { 3990 verndx = VER_NDX(obj->versyms[symnum]); 3991 if (verndx > obj->vernum) { 3992 _rtld_error( 3993 "%s: symbol %s references wrong version %d", 3994 obj->path, obj->strtab + symnum, verndx); 3995 return (false); 3996 } 3997 /* 3998 * If we are not called from dlsym (i.e. this 3999 * is a normal relocation from unversioned 4000 * binary), accept the symbol immediately if 4001 * it happens to have first version after this 4002 * shared object became versioned. Otherwise, 4003 * if symbol is versioned and not hidden, 4004 * remember it. If it is the only symbol with 4005 * this name exported by the shared object, it 4006 * will be returned as a match by the calling 4007 * function. If symbol is global (verndx < 2) 4008 * accept it unconditionally. 4009 */ 4010 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4011 verndx == VER_NDX_GIVEN) { 4012 result->sym_out = symp; 4013 return (true); 4014 } 4015 else if (verndx >= VER_NDX_GIVEN) { 4016 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4017 == 0) { 4018 if (result->vsymp == NULL) 4019 result->vsymp = symp; 4020 result->vcount++; 4021 } 4022 return (false); 4023 } 4024 } 4025 result->sym_out = symp; 4026 return (true); 4027 } 4028 if (obj->versyms == NULL) { 4029 if (object_match_name(obj, req->ventry->name)) { 4030 _rtld_error("%s: object %s should provide version %s " 4031 "for symbol %s", obj_rtld.path, obj->path, 4032 req->ventry->name, obj->strtab + symnum); 4033 return (false); 4034 } 4035 } else { 4036 verndx = VER_NDX(obj->versyms[symnum]); 4037 if (verndx > obj->vernum) { 4038 _rtld_error("%s: symbol %s references wrong version %d", 4039 obj->path, obj->strtab + symnum, verndx); 4040 return (false); 4041 } 4042 if (obj->vertab[verndx].hash != req->ventry->hash || 4043 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4044 /* 4045 * Version does not match. Look if this is a 4046 * global symbol and if it is not hidden. If 4047 * global symbol (verndx < 2) is available, 4048 * use it. Do not return symbol if we are 4049 * called by dlvsym, because dlvsym looks for 4050 * a specific version and default one is not 4051 * what dlvsym wants. 4052 */ 4053 if ((req->flags & SYMLOOK_DLSYM) || 4054 (verndx >= VER_NDX_GIVEN) || 4055 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4056 return (false); 4057 } 4058 } 4059 result->sym_out = symp; 4060 return (true); 4061 } 4062 4063 /* 4064 * Search for symbol using SysV hash function. 4065 * obj->buckets is known not to be NULL at this point; the test for this was 4066 * performed with the obj->valid_hash_sysv assignment. 4067 */ 4068 static int 4069 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4070 { 4071 unsigned long symnum; 4072 Sym_Match_Result matchres; 4073 4074 matchres.sym_out = NULL; 4075 matchres.vsymp = NULL; 4076 matchres.vcount = 0; 4077 4078 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4079 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4080 if (symnum >= obj->nchains) 4081 return (ESRCH); /* Bad object */ 4082 4083 if (matched_symbol(req, obj, &matchres, symnum)) { 4084 req->sym_out = matchres.sym_out; 4085 req->defobj_out = obj; 4086 return (0); 4087 } 4088 } 4089 if (matchres.vcount == 1) { 4090 req->sym_out = matchres.vsymp; 4091 req->defobj_out = obj; 4092 return (0); 4093 } 4094 return (ESRCH); 4095 } 4096 4097 /* Search for symbol using GNU hash function */ 4098 static int 4099 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4100 { 4101 Elf_Addr bloom_word; 4102 const Elf32_Word *hashval; 4103 Elf32_Word bucket; 4104 Sym_Match_Result matchres; 4105 unsigned int h1, h2; 4106 unsigned long symnum; 4107 4108 matchres.sym_out = NULL; 4109 matchres.vsymp = NULL; 4110 matchres.vcount = 0; 4111 4112 /* Pick right bitmask word from Bloom filter array */ 4113 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4114 obj->maskwords_bm_gnu]; 4115 4116 /* Calculate modulus word size of gnu hash and its derivative */ 4117 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4118 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4119 4120 /* Filter out the "definitely not in set" queries */ 4121 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4122 return (ESRCH); 4123 4124 /* Locate hash chain and corresponding value element*/ 4125 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4126 if (bucket == 0) 4127 return (ESRCH); 4128 hashval = &obj->chain_zero_gnu[bucket]; 4129 do { 4130 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4131 symnum = hashval - obj->chain_zero_gnu; 4132 if (matched_symbol(req, obj, &matchres, symnum)) { 4133 req->sym_out = matchres.sym_out; 4134 req->defobj_out = obj; 4135 return (0); 4136 } 4137 } 4138 } while ((*hashval++ & 1) == 0); 4139 if (matchres.vcount == 1) { 4140 req->sym_out = matchres.vsymp; 4141 req->defobj_out = obj; 4142 return (0); 4143 } 4144 return (ESRCH); 4145 } 4146 4147 static void 4148 trace_loaded_objects(Obj_Entry *obj) 4149 { 4150 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4151 int c; 4152 4153 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 4154 main_local = ""; 4155 4156 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL) 4157 fmt1 = "\t%o => %p (%x)\n"; 4158 4159 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL) 4160 fmt2 = "\t%o (%x)\n"; 4161 4162 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL"); 4163 4164 for (; obj; obj = obj->next) { 4165 Needed_Entry *needed; 4166 char *name, *path; 4167 bool is_lib; 4168 4169 if (list_containers && obj->needed != NULL) 4170 rtld_printf("%s:\n", obj->path); 4171 for (needed = obj->needed; needed; needed = needed->next) { 4172 if (needed->obj != NULL) { 4173 if (needed->obj->traced && !list_containers) 4174 continue; 4175 needed->obj->traced = true; 4176 path = needed->obj->path; 4177 } else 4178 path = "not found"; 4179 4180 name = (char *)obj->strtab + needed->name; 4181 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4182 4183 fmt = is_lib ? fmt1 : fmt2; 4184 while ((c = *fmt++) != '\0') { 4185 switch (c) { 4186 default: 4187 rtld_putchar(c); 4188 continue; 4189 case '\\': 4190 switch (c = *fmt) { 4191 case '\0': 4192 continue; 4193 case 'n': 4194 rtld_putchar('\n'); 4195 break; 4196 case 't': 4197 rtld_putchar('\t'); 4198 break; 4199 } 4200 break; 4201 case '%': 4202 switch (c = *fmt) { 4203 case '\0': 4204 continue; 4205 case '%': 4206 default: 4207 rtld_putchar(c); 4208 break; 4209 case 'A': 4210 rtld_putstr(main_local); 4211 break; 4212 case 'a': 4213 rtld_putstr(obj_main->path); 4214 break; 4215 case 'o': 4216 rtld_putstr(name); 4217 break; 4218 #if 0 4219 case 'm': 4220 rtld_printf("%d", sodp->sod_major); 4221 break; 4222 case 'n': 4223 rtld_printf("%d", sodp->sod_minor); 4224 break; 4225 #endif 4226 case 'p': 4227 rtld_putstr(path); 4228 break; 4229 case 'x': 4230 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4231 0); 4232 break; 4233 } 4234 break; 4235 } 4236 ++fmt; 4237 } 4238 } 4239 } 4240 } 4241 4242 /* 4243 * Unload a dlopened object and its dependencies from memory and from 4244 * our data structures. It is assumed that the DAG rooted in the 4245 * object has already been unreferenced, and that the object has a 4246 * reference count of 0. 4247 */ 4248 static void 4249 unload_object(Obj_Entry *root) 4250 { 4251 Obj_Entry *obj; 4252 Obj_Entry **linkp; 4253 4254 assert(root->refcount == 0); 4255 4256 /* 4257 * Pass over the DAG removing unreferenced objects from 4258 * appropriate lists. 4259 */ 4260 unlink_object(root); 4261 4262 /* Unmap all objects that are no longer referenced. */ 4263 linkp = &obj_list->next; 4264 while ((obj = *linkp) != NULL) { 4265 if (obj->refcount == 0) { 4266 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 4267 obj->path); 4268 dbg("unloading \"%s\"", obj->path); 4269 unload_filtees(root); 4270 munmap(obj->mapbase, obj->mapsize); 4271 linkmap_delete(obj); 4272 *linkp = obj->next; 4273 obj_count--; 4274 obj_free(obj); 4275 } else 4276 linkp = &obj->next; 4277 } 4278 obj_tail = linkp; 4279 } 4280 4281 static void 4282 unlink_object(Obj_Entry *root) 4283 { 4284 Objlist_Entry *elm; 4285 4286 if (root->refcount == 0) { 4287 /* Remove the object from the RTLD_GLOBAL list. */ 4288 objlist_remove(&list_global, root); 4289 4290 /* Remove the object from all objects' DAG lists. */ 4291 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4292 objlist_remove(&elm->obj->dldags, root); 4293 if (elm->obj != root) 4294 unlink_object(elm->obj); 4295 } 4296 } 4297 } 4298 4299 static void 4300 ref_dag(Obj_Entry *root) 4301 { 4302 Objlist_Entry *elm; 4303 4304 assert(root->dag_inited); 4305 STAILQ_FOREACH(elm, &root->dagmembers, link) 4306 elm->obj->refcount++; 4307 } 4308 4309 static void 4310 unref_dag(Obj_Entry *root) 4311 { 4312 Objlist_Entry *elm; 4313 4314 assert(root->dag_inited); 4315 STAILQ_FOREACH(elm, &root->dagmembers, link) 4316 elm->obj->refcount--; 4317 } 4318 4319 /* 4320 * Common code for MD __tls_get_addr(). 4321 */ 4322 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4323 static void * 4324 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4325 { 4326 Elf_Addr *newdtv, *dtv; 4327 RtldLockState lockstate; 4328 int to_copy; 4329 4330 dtv = *dtvp; 4331 /* Check dtv generation in case new modules have arrived */ 4332 if (dtv[0] != tls_dtv_generation) { 4333 wlock_acquire(rtld_bind_lock, &lockstate); 4334 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4335 to_copy = dtv[1]; 4336 if (to_copy > tls_max_index) 4337 to_copy = tls_max_index; 4338 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4339 newdtv[0] = tls_dtv_generation; 4340 newdtv[1] = tls_max_index; 4341 free(dtv); 4342 lock_release(rtld_bind_lock, &lockstate); 4343 dtv = *dtvp = newdtv; 4344 } 4345 4346 /* Dynamically allocate module TLS if necessary */ 4347 if (dtv[index + 1] == 0) { 4348 /* Signal safe, wlock will block out signals. */ 4349 wlock_acquire(rtld_bind_lock, &lockstate); 4350 if (!dtv[index + 1]) 4351 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4352 lock_release(rtld_bind_lock, &lockstate); 4353 } 4354 return ((void *)(dtv[index + 1] + offset)); 4355 } 4356 4357 void * 4358 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4359 { 4360 Elf_Addr *dtv; 4361 4362 dtv = *dtvp; 4363 /* Check dtv generation in case new modules have arrived */ 4364 if (__predict_true(dtv[0] == tls_dtv_generation && 4365 dtv[index + 1] != 0)) 4366 return ((void *)(dtv[index + 1] + offset)); 4367 return (tls_get_addr_slow(dtvp, index, offset)); 4368 } 4369 4370 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \ 4371 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 rtld_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 rtld_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 rtld_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 rtld_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