1 /*- 2 * Copyright (c) 1998-2000 Doug Rabson 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 */ 26 27 #include <sys/cdefs.h> 28 __FBSDID("$FreeBSD$"); 29 30 #include "opt_gdb.h" 31 #include "opt_mac.h" 32 33 #include <sys/param.h> 34 #include <sys/systm.h> 35 #ifdef GPROF 36 #include <sys/gmon.h> 37 #endif 38 #include <sys/kernel.h> 39 #include <sys/lock.h> 40 #include <sys/malloc.h> 41 #include <sys/mutex.h> 42 #include <sys/mount.h> 43 #include <sys/proc.h> 44 #include <sys/namei.h> 45 #include <sys/fcntl.h> 46 #include <sys/vnode.h> 47 #include <sys/linker.h> 48 49 #include <machine/elf.h> 50 51 #include <security/mac/mac_framework.h> 52 53 #include <vm/vm.h> 54 #include <vm/vm_param.h> 55 #ifdef SPARSE_MAPPING 56 #include <vm/vm_object.h> 57 #include <vm/vm_kern.h> 58 #include <vm/vm_extern.h> 59 #endif 60 #include <vm/pmap.h> 61 #include <vm/vm_map.h> 62 63 #include <sys/link_elf.h> 64 65 #include "linker_if.h" 66 67 #define MAXSEGS 4 68 69 typedef struct elf_file { 70 struct linker_file lf; /* Common fields */ 71 int preloaded; /* Was file pre-loaded */ 72 caddr_t address; /* Relocation address */ 73 #ifdef SPARSE_MAPPING 74 vm_object_t object; /* VM object to hold file pages */ 75 #endif 76 Elf_Dyn* dynamic; /* Symbol table etc. */ 77 Elf_Hashelt nbuckets; /* DT_HASH info */ 78 Elf_Hashelt nchains; 79 const Elf_Hashelt* buckets; 80 const Elf_Hashelt* chains; 81 caddr_t hash; 82 caddr_t strtab; /* DT_STRTAB */ 83 int strsz; /* DT_STRSZ */ 84 const Elf_Sym* symtab; /* DT_SYMTAB */ 85 Elf_Addr* got; /* DT_PLTGOT */ 86 const Elf_Rel* pltrel; /* DT_JMPREL */ 87 int pltrelsize; /* DT_PLTRELSZ */ 88 const Elf_Rela* pltrela; /* DT_JMPREL */ 89 int pltrelasize; /* DT_PLTRELSZ */ 90 const Elf_Rel* rel; /* DT_REL */ 91 int relsize; /* DT_RELSZ */ 92 const Elf_Rela* rela; /* DT_RELA */ 93 int relasize; /* DT_RELASZ */ 94 caddr_t modptr; 95 const Elf_Sym* ddbsymtab; /* The symbol table we are using */ 96 long ddbsymcnt; /* Number of symbols */ 97 caddr_t ddbstrtab; /* String table */ 98 long ddbstrcnt; /* number of bytes in string table */ 99 caddr_t symbase; /* malloc'ed symbold base */ 100 caddr_t strbase; /* malloc'ed string base */ 101 #ifdef GDB 102 struct link_map gdb; /* hooks for gdb */ 103 #endif 104 } *elf_file_t; 105 106 static int link_elf_link_common_finish(linker_file_t); 107 static int link_elf_link_preload(linker_class_t cls, 108 const char*, linker_file_t*); 109 static int link_elf_link_preload_finish(linker_file_t); 110 static int link_elf_load_file(linker_class_t, const char*, linker_file_t*); 111 static int link_elf_lookup_symbol(linker_file_t, const char*, 112 c_linker_sym_t*); 113 static int link_elf_symbol_values(linker_file_t, c_linker_sym_t, linker_symval_t*); 114 static int link_elf_search_symbol(linker_file_t, caddr_t value, 115 c_linker_sym_t* sym, long* diffp); 116 117 static void link_elf_unload_file(linker_file_t); 118 static void link_elf_unload_preload(linker_file_t); 119 static int link_elf_lookup_set(linker_file_t, const char *, 120 void ***, void ***, int *); 121 static int link_elf_each_function_name(linker_file_t, 122 int (*)(const char *, void *), 123 void *); 124 static void link_elf_reloc_local(linker_file_t); 125 static Elf_Addr elf_lookup(linker_file_t lf, Elf_Size symidx, int deps); 126 127 static kobj_method_t link_elf_methods[] = { 128 KOBJMETHOD(linker_lookup_symbol, link_elf_lookup_symbol), 129 KOBJMETHOD(linker_symbol_values, link_elf_symbol_values), 130 KOBJMETHOD(linker_search_symbol, link_elf_search_symbol), 131 KOBJMETHOD(linker_unload, link_elf_unload_file), 132 KOBJMETHOD(linker_load_file, link_elf_load_file), 133 KOBJMETHOD(linker_link_preload, link_elf_link_preload), 134 KOBJMETHOD(linker_link_preload_finish, link_elf_link_preload_finish), 135 KOBJMETHOD(linker_lookup_set, link_elf_lookup_set), 136 KOBJMETHOD(linker_each_function_name, link_elf_each_function_name), 137 { 0, 0 } 138 }; 139 140 static struct linker_class link_elf_class = { 141 #if ELF_TARG_CLASS == ELFCLASS32 142 "elf32", 143 #else 144 "elf64", 145 #endif 146 link_elf_methods, sizeof(struct elf_file) 147 }; 148 149 static int parse_dynamic(elf_file_t ef); 150 static int relocate_file(elf_file_t ef); 151 static int link_elf_preload_parse_symbols(elf_file_t ef); 152 153 #ifdef GDB 154 static void r_debug_state(struct r_debug *dummy_one, 155 struct link_map *dummy_two); 156 157 /* 158 * A list of loaded modules for GDB to use for loading symbols. 159 */ 160 struct r_debug r_debug; 161 162 #define GDB_STATE(s) r_debug.r_state = s; r_debug_state(NULL, NULL); 163 164 /* 165 * Function for the debugger to set a breakpoint on to gain control. 166 */ 167 static void 168 r_debug_state(struct r_debug *dummy_one __unused, 169 struct link_map *dummy_two __unused) 170 { 171 } 172 173 static void 174 link_elf_add_gdb(struct link_map *l) 175 { 176 struct link_map *prev; 177 178 l->l_next = NULL; 179 180 if (r_debug.r_map == NULL) { 181 /* Add first. */ 182 l->l_prev = NULL; 183 r_debug.r_map = l; 184 } else { 185 /* Append to list. */ 186 for (prev = r_debug.r_map; prev->l_next != NULL; prev = prev->l_next) 187 ; 188 l->l_prev = prev; 189 prev->l_next = l; 190 } 191 } 192 193 static void 194 link_elf_delete_gdb(struct link_map *l) 195 { 196 if (l->l_prev == NULL) { 197 /* Remove first. */ 198 if ((r_debug.r_map = l->l_next) != NULL) 199 l->l_next->l_prev = NULL; 200 } else { 201 /* Remove any but first. */ 202 if ((l->l_prev->l_next = l->l_next) != NULL) 203 l->l_next->l_prev = l->l_prev; 204 } 205 } 206 #endif /* GDB */ 207 208 #ifdef __ia64__ 209 Elf_Addr link_elf_get_gp(linker_file_t); 210 #endif 211 212 /* 213 * The kernel symbol table starts here. 214 */ 215 extern struct _dynamic _DYNAMIC; 216 217 static void 218 link_elf_error(const char *s) 219 { 220 printf("kldload: %s\n", s); 221 } 222 223 /* 224 * Actions performed after linking/loading both the preloaded kernel and any 225 * modules; whether preloaded or dynamicly loaded. 226 */ 227 static int 228 link_elf_link_common_finish(linker_file_t lf) 229 { 230 #ifdef GDB 231 elf_file_t ef = (elf_file_t)lf; 232 char *newfilename; 233 #endif 234 int error; 235 236 /* Notify MD code that a module is being loaded. */ 237 error = elf_cpu_load_file(lf); 238 if (error) 239 return (error); 240 241 #ifdef GDB 242 GDB_STATE(RT_ADD); 243 ef->gdb.l_addr = lf->address; 244 newfilename = malloc(strlen(lf->filename) + 1, M_LINKER, M_WAITOK); 245 strcpy(newfilename, lf->filename); 246 ef->gdb.l_name = newfilename; 247 ef->gdb.l_ld = ef->dynamic; 248 link_elf_add_gdb(&ef->gdb); 249 GDB_STATE(RT_CONSISTENT); 250 #endif 251 252 return (0); 253 } 254 255 static void 256 link_elf_init(void* arg) 257 { 258 Elf_Dyn *dp; 259 caddr_t modptr, baseptr, sizeptr; 260 elf_file_t ef; 261 char *modname; 262 263 linker_add_class(&link_elf_class); 264 265 dp = (Elf_Dyn*) &_DYNAMIC; 266 modname = NULL; 267 modptr = preload_search_by_type("elf" __XSTRING(__ELF_WORD_SIZE) " kernel"); 268 if (modptr == NULL) 269 modptr = preload_search_by_type("elf kernel"); 270 if (modptr) 271 modname = (char *)preload_search_info(modptr, MODINFO_NAME); 272 if (modname == NULL) 273 modname = "kernel"; 274 linker_kernel_file = linker_make_file(modname, &link_elf_class); 275 if (linker_kernel_file == NULL) 276 panic("link_elf_init: Can't create linker structures for kernel"); 277 278 ef = (elf_file_t) linker_kernel_file; 279 ef->preloaded = 1; 280 ef->address = 0; 281 #ifdef SPARSE_MAPPING 282 ef->object = 0; 283 #endif 284 ef->dynamic = dp; 285 286 if (dp) 287 parse_dynamic(ef); 288 linker_kernel_file->address = (caddr_t) KERNBASE; 289 linker_kernel_file->size = -(intptr_t)linker_kernel_file->address; 290 291 if (modptr) { 292 ef->modptr = modptr; 293 baseptr = preload_search_info(modptr, MODINFO_ADDR); 294 if (baseptr) 295 linker_kernel_file->address = *(caddr_t *)baseptr; 296 sizeptr = preload_search_info(modptr, MODINFO_SIZE); 297 if (sizeptr) 298 linker_kernel_file->size = *(size_t *)sizeptr; 299 } 300 (void)link_elf_preload_parse_symbols(ef); 301 302 #ifdef GDB 303 r_debug.r_map = NULL; 304 r_debug.r_brk = r_debug_state; 305 r_debug.r_state = RT_CONSISTENT; 306 #endif 307 308 (void)link_elf_link_common_finish(linker_kernel_file); 309 linker_kernel_file->flags |= LINKER_FILE_LINKED; 310 } 311 312 SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_THIRD, link_elf_init, 0); 313 314 static int 315 link_elf_preload_parse_symbols(elf_file_t ef) 316 { 317 caddr_t pointer; 318 caddr_t ssym, esym, base; 319 caddr_t strtab; 320 int strcnt; 321 Elf_Sym* symtab; 322 int symcnt; 323 324 if (ef->modptr == NULL) 325 return 0; 326 pointer = preload_search_info(ef->modptr, MODINFO_METADATA|MODINFOMD_SSYM); 327 if (pointer == NULL) 328 return 0; 329 ssym = *(caddr_t *)pointer; 330 pointer = preload_search_info(ef->modptr, MODINFO_METADATA|MODINFOMD_ESYM); 331 if (pointer == NULL) 332 return 0; 333 esym = *(caddr_t *)pointer; 334 335 base = ssym; 336 337 symcnt = *(long *)base; 338 base += sizeof(long); 339 symtab = (Elf_Sym *)base; 340 base += roundup(symcnt, sizeof(long)); 341 342 if (base > esym || base < ssym) { 343 printf("Symbols are corrupt!\n"); 344 return EINVAL; 345 } 346 347 strcnt = *(long *)base; 348 base += sizeof(long); 349 strtab = base; 350 base += roundup(strcnt, sizeof(long)); 351 352 if (base > esym || base < ssym) { 353 printf("Symbols are corrupt!\n"); 354 return EINVAL; 355 } 356 357 ef->ddbsymtab = symtab; 358 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym); 359 ef->ddbstrtab = strtab; 360 ef->ddbstrcnt = strcnt; 361 362 return 0; 363 } 364 365 static int 366 parse_dynamic(elf_file_t ef) 367 { 368 Elf_Dyn *dp; 369 int plttype = DT_REL; 370 371 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) { 372 switch (dp->d_tag) { 373 case DT_HASH: 374 { 375 /* From src/libexec/rtld-elf/rtld.c */ 376 const Elf_Hashelt *hashtab = (const Elf_Hashelt *) 377 (ef->address + dp->d_un.d_ptr); 378 ef->nbuckets = hashtab[0]; 379 ef->nchains = hashtab[1]; 380 ef->buckets = hashtab + 2; 381 ef->chains = ef->buckets + ef->nbuckets; 382 break; 383 } 384 case DT_STRTAB: 385 ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr); 386 break; 387 case DT_STRSZ: 388 ef->strsz = dp->d_un.d_val; 389 break; 390 case DT_SYMTAB: 391 ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr); 392 break; 393 case DT_SYMENT: 394 if (dp->d_un.d_val != sizeof(Elf_Sym)) 395 return ENOEXEC; 396 break; 397 case DT_PLTGOT: 398 ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr); 399 break; 400 case DT_REL: 401 ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr); 402 break; 403 case DT_RELSZ: 404 ef->relsize = dp->d_un.d_val; 405 break; 406 case DT_RELENT: 407 if (dp->d_un.d_val != sizeof(Elf_Rel)) 408 return ENOEXEC; 409 break; 410 case DT_JMPREL: 411 ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr); 412 break; 413 case DT_PLTRELSZ: 414 ef->pltrelsize = dp->d_un.d_val; 415 break; 416 case DT_RELA: 417 ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr); 418 break; 419 case DT_RELASZ: 420 ef->relasize = dp->d_un.d_val; 421 break; 422 case DT_RELAENT: 423 if (dp->d_un.d_val != sizeof(Elf_Rela)) 424 return ENOEXEC; 425 break; 426 case DT_PLTREL: 427 plttype = dp->d_un.d_val; 428 if (plttype != DT_REL && plttype != DT_RELA) 429 return ENOEXEC; 430 break; 431 #ifdef GDB 432 case DT_DEBUG: 433 dp->d_un.d_ptr = (Elf_Addr) &r_debug; 434 break; 435 #endif 436 } 437 } 438 439 if (plttype == DT_RELA) { 440 ef->pltrela = (const Elf_Rela *) ef->pltrel; 441 ef->pltrel = NULL; 442 ef->pltrelasize = ef->pltrelsize; 443 ef->pltrelsize = 0; 444 } 445 446 ef->ddbsymtab = ef->symtab; 447 ef->ddbsymcnt = ef->nchains; 448 ef->ddbstrtab = ef->strtab; 449 ef->ddbstrcnt = ef->strsz; 450 451 return 0; 452 } 453 454 static int 455 link_elf_link_preload(linker_class_t cls, 456 const char* filename, linker_file_t *result) 457 { 458 caddr_t modptr, baseptr, sizeptr, dynptr; 459 char *type; 460 elf_file_t ef; 461 linker_file_t lf; 462 int error; 463 vm_offset_t dp; 464 465 /* Look to see if we have the file preloaded */ 466 modptr = preload_search_by_name(filename); 467 if (modptr == NULL) 468 return ENOENT; 469 470 type = (char *)preload_search_info(modptr, MODINFO_TYPE); 471 baseptr = preload_search_info(modptr, MODINFO_ADDR); 472 sizeptr = preload_search_info(modptr, MODINFO_SIZE); 473 dynptr = preload_search_info(modptr, MODINFO_METADATA|MODINFOMD_DYNAMIC); 474 if (type == NULL || 475 (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) " module") != 0 && 476 strcmp(type, "elf module") != 0)) 477 return (EFTYPE); 478 if (baseptr == NULL || sizeptr == NULL || dynptr == NULL) 479 return (EINVAL); 480 481 lf = linker_make_file(filename, &link_elf_class); 482 if (lf == NULL) { 483 return ENOMEM; 484 } 485 486 ef = (elf_file_t) lf; 487 ef->preloaded = 1; 488 ef->modptr = modptr; 489 ef->address = *(caddr_t *)baseptr; 490 #ifdef SPARSE_MAPPING 491 ef->object = 0; 492 #endif 493 dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr; 494 ef->dynamic = (Elf_Dyn *)dp; 495 lf->address = ef->address; 496 lf->size = *(size_t *)sizeptr; 497 498 error = parse_dynamic(ef); 499 if (error) { 500 linker_file_unload(lf, LINKER_UNLOAD_FORCE); 501 return error; 502 } 503 link_elf_reloc_local(lf); 504 *result = lf; 505 return (0); 506 } 507 508 static int 509 link_elf_link_preload_finish(linker_file_t lf) 510 { 511 elf_file_t ef; 512 int error; 513 514 ef = (elf_file_t) lf; 515 #if 0 /* this will be more trouble than it's worth for now */ 516 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) { 517 if (dp->d_tag != DT_NEEDED) 518 continue; 519 modname = ef->strtab + dp->d_un.d_val; 520 error = linker_load_module(modname, lf); 521 if (error) 522 goto out; 523 } 524 #endif 525 error = relocate_file(ef); 526 if (error) 527 return error; 528 (void)link_elf_preload_parse_symbols(ef); 529 530 return (link_elf_link_common_finish(lf)); 531 } 532 533 static int 534 link_elf_load_file(linker_class_t cls, const char* filename, 535 linker_file_t* result) 536 { 537 struct nameidata nd; 538 struct thread* td = curthread; /* XXX */ 539 Elf_Ehdr *hdr; 540 caddr_t firstpage; 541 int nbytes, i; 542 Elf_Phdr *phdr; 543 Elf_Phdr *phlimit; 544 Elf_Phdr *segs[MAXSEGS]; 545 int nsegs; 546 Elf_Phdr *phdyn; 547 Elf_Phdr *phphdr; 548 caddr_t mapbase; 549 size_t mapsize; 550 Elf_Off base_offset; 551 Elf_Addr base_vaddr; 552 Elf_Addr base_vlimit; 553 int error = 0; 554 int resid, flags; 555 elf_file_t ef; 556 linker_file_t lf; 557 Elf_Shdr *shdr; 558 int symtabindex; 559 int symstrindex; 560 int symcnt; 561 int strcnt; 562 int vfslocked; 563 564 shdr = NULL; 565 lf = NULL; 566 567 NDINIT(&nd, LOOKUP, FOLLOW | MPSAFE, UIO_SYSSPACE, filename, td); 568 flags = FREAD; 569 error = vn_open(&nd, &flags, 0, NULL); 570 if (error) 571 return error; 572 vfslocked = NDHASGIANT(&nd); 573 NDFREE(&nd, NDF_ONLY_PNBUF); 574 #ifdef MAC 575 error = mac_kld_check_load(curthread->td_ucred, nd.ni_vp); 576 if (error) { 577 firstpage = NULL; 578 goto out; 579 } 580 #endif 581 582 /* 583 * Read the elf header from the file. 584 */ 585 firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK); 586 if (firstpage == NULL) { 587 error = ENOMEM; 588 goto out; 589 } 590 hdr = (Elf_Ehdr *)firstpage; 591 error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0, 592 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 593 &resid, td); 594 nbytes = PAGE_SIZE - resid; 595 if (error) 596 goto out; 597 598 if (!IS_ELF(*hdr)) { 599 error = ENOEXEC; 600 goto out; 601 } 602 603 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS 604 || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) { 605 link_elf_error("Unsupported file layout"); 606 error = ENOEXEC; 607 goto out; 608 } 609 if (hdr->e_ident[EI_VERSION] != EV_CURRENT 610 || hdr->e_version != EV_CURRENT) { 611 link_elf_error("Unsupported file version"); 612 error = ENOEXEC; 613 goto out; 614 } 615 if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) { 616 link_elf_error("Unsupported file type"); 617 error = ENOEXEC; 618 goto out; 619 } 620 if (hdr->e_machine != ELF_TARG_MACH) { 621 link_elf_error("Unsupported machine"); 622 error = ENOEXEC; 623 goto out; 624 } 625 626 /* 627 * We rely on the program header being in the first page. This is 628 * not strictly required by the ABI specification, but it seems to 629 * always true in practice. And, it simplifies things considerably. 630 */ 631 if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) && 632 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) && 633 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes))) 634 link_elf_error("Unreadable program headers"); 635 636 /* 637 * Scan the program header entries, and save key information. 638 * 639 * We rely on there being exactly two load segments, text and data, 640 * in that order. 641 */ 642 phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff); 643 phlimit = phdr + hdr->e_phnum; 644 nsegs = 0; 645 phdyn = NULL; 646 phphdr = NULL; 647 while (phdr < phlimit) { 648 switch (phdr->p_type) { 649 650 case PT_LOAD: 651 if (nsegs == MAXSEGS) { 652 link_elf_error("Too many sections"); 653 error = ENOEXEC; 654 goto out; 655 } 656 /* 657 * XXX: We just trust they come in right order ?? 658 */ 659 segs[nsegs] = phdr; 660 ++nsegs; 661 break; 662 663 case PT_PHDR: 664 phphdr = phdr; 665 break; 666 667 case PT_DYNAMIC: 668 phdyn = phdr; 669 break; 670 671 case PT_INTERP: 672 link_elf_error("Unsupported file type"); 673 error = ENOEXEC; 674 goto out; 675 } 676 677 ++phdr; 678 } 679 if (phdyn == NULL) { 680 link_elf_error("Object is not dynamically-linked"); 681 error = ENOEXEC; 682 goto out; 683 } 684 if (nsegs == 0) { 685 link_elf_error("No sections"); 686 error = ENOEXEC; 687 goto out; 688 } 689 690 /* 691 * Allocate the entire address space of the object, to stake out our 692 * contiguous region, and to establish the base address for relocation. 693 */ 694 base_offset = trunc_page(segs[0]->p_offset); 695 base_vaddr = trunc_page(segs[0]->p_vaddr); 696 base_vlimit = round_page(segs[nsegs - 1]->p_vaddr + 697 segs[nsegs - 1]->p_memsz); 698 mapsize = base_vlimit - base_vaddr; 699 700 lf = linker_make_file(filename, &link_elf_class); 701 if (!lf) { 702 error = ENOMEM; 703 goto out; 704 } 705 706 ef = (elf_file_t) lf; 707 #ifdef SPARSE_MAPPING 708 ef->object = vm_object_allocate(OBJT_DEFAULT, mapsize >> PAGE_SHIFT); 709 if (ef->object == NULL) { 710 error = ENOMEM; 711 goto out; 712 } 713 ef->address = (caddr_t) vm_map_min(kernel_map); 714 error = vm_map_find(kernel_map, ef->object, 0, 715 (vm_offset_t *) &ef->address, 716 mapsize, 1, 717 VM_PROT_ALL, VM_PROT_ALL, 0); 718 if (error) { 719 vm_object_deallocate(ef->object); 720 ef->object = 0; 721 goto out; 722 } 723 #else 724 ef->address = malloc(mapsize, M_LINKER, M_WAITOK); 725 if (!ef->address) { 726 error = ENOMEM; 727 goto out; 728 } 729 #endif 730 mapbase = ef->address; 731 732 /* 733 * Read the text and data sections and zero the bss. 734 */ 735 for (i = 0; i < nsegs; i++) { 736 caddr_t segbase = mapbase + segs[i]->p_vaddr - base_vaddr; 737 error = vn_rdwr(UIO_READ, nd.ni_vp, 738 segbase, segs[i]->p_filesz, segs[i]->p_offset, 739 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 740 &resid, td); 741 if (error) { 742 goto out; 743 } 744 bzero(segbase + segs[i]->p_filesz, 745 segs[i]->p_memsz - segs[i]->p_filesz); 746 747 #ifdef SPARSE_MAPPING 748 /* 749 * Wire down the pages 750 */ 751 error = vm_map_wire(kernel_map, 752 (vm_offset_t) segbase, 753 (vm_offset_t) segbase + segs[i]->p_memsz, 754 VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES); 755 if (error != KERN_SUCCESS) { 756 error = ENOMEM; 757 goto out; 758 } 759 #endif 760 } 761 762 #ifdef GPROF 763 /* Update profiling information with the new text segment. */ 764 mtx_lock(&Giant); 765 kmupetext((uintfptr_t)(mapbase + segs[0]->p_vaddr - base_vaddr + 766 segs[0]->p_memsz)); 767 mtx_unlock(&Giant); 768 #endif 769 770 ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr); 771 772 lf->address = ef->address; 773 lf->size = mapsize; 774 775 error = parse_dynamic(ef); 776 if (error) 777 goto out; 778 link_elf_reloc_local(lf); 779 780 error = linker_load_dependencies(lf); 781 if (error) 782 goto out; 783 #if 0 /* this will be more trouble than it's worth for now */ 784 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) { 785 if (dp->d_tag != DT_NEEDED) 786 continue; 787 modname = ef->strtab + dp->d_un.d_val; 788 error = linker_load_module(modname, lf); 789 if (error) 790 goto out; 791 } 792 #endif 793 error = relocate_file(ef); 794 if (error) 795 goto out; 796 797 /* Try and load the symbol table if it's present. (you can strip it!) */ 798 nbytes = hdr->e_shnum * hdr->e_shentsize; 799 if (nbytes == 0 || hdr->e_shoff == 0) 800 goto nosyms; 801 shdr = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO); 802 if (shdr == NULL) { 803 error = ENOMEM; 804 goto out; 805 } 806 error = vn_rdwr(UIO_READ, nd.ni_vp, 807 (caddr_t)shdr, nbytes, hdr->e_shoff, 808 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 809 &resid, td); 810 if (error) 811 goto out; 812 symtabindex = -1; 813 symstrindex = -1; 814 for (i = 0; i < hdr->e_shnum; i++) { 815 if (shdr[i].sh_type == SHT_SYMTAB) { 816 symtabindex = i; 817 symstrindex = shdr[i].sh_link; 818 } 819 } 820 if (symtabindex < 0 || symstrindex < 0) 821 goto nosyms; 822 823 symcnt = shdr[symtabindex].sh_size; 824 ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK); 825 strcnt = shdr[symstrindex].sh_size; 826 ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK); 827 828 if (ef->symbase == NULL || ef->strbase == NULL) { 829 error = ENOMEM; 830 goto out; 831 } 832 error = vn_rdwr(UIO_READ, nd.ni_vp, 833 ef->symbase, symcnt, shdr[symtabindex].sh_offset, 834 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 835 &resid, td); 836 if (error) 837 goto out; 838 error = vn_rdwr(UIO_READ, nd.ni_vp, 839 ef->strbase, strcnt, shdr[symstrindex].sh_offset, 840 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 841 &resid, td); 842 if (error) 843 goto out; 844 845 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym); 846 ef->ddbsymtab = (const Elf_Sym *)ef->symbase; 847 ef->ddbstrcnt = strcnt; 848 ef->ddbstrtab = ef->strbase; 849 850 error = link_elf_link_common_finish(lf); 851 if (error) 852 goto out; 853 854 nosyms: 855 856 *result = lf; 857 858 out: 859 if (error && lf) 860 linker_file_unload(lf, LINKER_UNLOAD_FORCE); 861 if (shdr) 862 free(shdr, M_LINKER); 863 if (firstpage) 864 free(firstpage, M_LINKER); 865 VOP_UNLOCK(nd.ni_vp, 0); 866 vn_close(nd.ni_vp, FREAD, td->td_ucred, td); 867 VFS_UNLOCK_GIANT(vfslocked); 868 869 return error; 870 } 871 872 static void 873 link_elf_unload_file(linker_file_t file) 874 { 875 elf_file_t ef = (elf_file_t) file; 876 877 #ifdef GDB 878 if (ef->gdb.l_ld) { 879 GDB_STATE(RT_DELETE); 880 free((void *)(uintptr_t)ef->gdb.l_name, M_LINKER); 881 link_elf_delete_gdb(&ef->gdb); 882 GDB_STATE(RT_CONSISTENT); 883 } 884 #endif 885 886 /* Notify MD code that a module is being unloaded. */ 887 elf_cpu_unload_file(file); 888 889 if (ef->preloaded) { 890 link_elf_unload_preload(file); 891 return; 892 } 893 894 #ifdef SPARSE_MAPPING 895 if (ef->object) { 896 vm_map_remove(kernel_map, (vm_offset_t) ef->address, 897 (vm_offset_t) ef->address 898 + (ef->object->size << PAGE_SHIFT)); 899 } 900 #else 901 if (ef->address) 902 free(ef->address, M_LINKER); 903 #endif 904 if (ef->symbase) 905 free(ef->symbase, M_LINKER); 906 if (ef->strbase) 907 free(ef->strbase, M_LINKER); 908 } 909 910 static void 911 link_elf_unload_preload(linker_file_t file) 912 { 913 if (file->filename) 914 preload_delete_name(file->filename); 915 } 916 917 static const char * 918 symbol_name(elf_file_t ef, Elf_Size r_info) 919 { 920 const Elf_Sym *ref; 921 922 if (ELF_R_SYM(r_info)) { 923 ref = ef->symtab + ELF_R_SYM(r_info); 924 return ef->strtab + ref->st_name; 925 } else 926 return NULL; 927 } 928 929 static int 930 relocate_file(elf_file_t ef) 931 { 932 const Elf_Rel *rellim; 933 const Elf_Rel *rel; 934 const Elf_Rela *relalim; 935 const Elf_Rela *rela; 936 const char *symname; 937 938 /* Perform relocations without addend if there are any: */ 939 rel = ef->rel; 940 if (rel) { 941 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize); 942 while (rel < rellim) { 943 if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rel, ELF_RELOC_REL, 944 elf_lookup)) { 945 symname = symbol_name(ef, rel->r_info); 946 printf("link_elf: symbol %s undefined\n", symname); 947 return ENOENT; 948 } 949 rel++; 950 } 951 } 952 953 /* Perform relocations with addend if there are any: */ 954 rela = ef->rela; 955 if (rela) { 956 relalim = (const Elf_Rela *)((const char *)ef->rela + ef->relasize); 957 while (rela < relalim) { 958 if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rela, ELF_RELOC_RELA, 959 elf_lookup)) { 960 symname = symbol_name(ef, rela->r_info); 961 printf("link_elf: symbol %s undefined\n", symname); 962 return ENOENT; 963 } 964 rela++; 965 } 966 } 967 968 /* Perform PLT relocations without addend if there are any: */ 969 rel = ef->pltrel; 970 if (rel) { 971 rellim = (const Elf_Rel *)((const char *)ef->pltrel + ef->pltrelsize); 972 while (rel < rellim) { 973 if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rel, ELF_RELOC_REL, 974 elf_lookup)) { 975 symname = symbol_name(ef, rel->r_info); 976 printf("link_elf: symbol %s undefined\n", symname); 977 return ENOENT; 978 } 979 rel++; 980 } 981 } 982 983 /* Perform relocations with addend if there are any: */ 984 rela = ef->pltrela; 985 if (rela) { 986 relalim = (const Elf_Rela *)((const char *)ef->pltrela + ef->pltrelasize); 987 while (rela < relalim) { 988 if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rela, ELF_RELOC_RELA, 989 elf_lookup)) { 990 symname = symbol_name(ef, rela->r_info); 991 printf("link_elf: symbol %s undefined\n", symname); 992 return ENOENT; 993 } 994 rela++; 995 } 996 } 997 998 return 0; 999 } 1000 1001 /* 1002 * Hash function for symbol table lookup. Don't even think about changing 1003 * this. It is specified by the System V ABI. 1004 */ 1005 static unsigned long 1006 elf_hash(const char *name) 1007 { 1008 const unsigned char *p = (const unsigned char *) name; 1009 unsigned long h = 0; 1010 unsigned long g; 1011 1012 while (*p != '\0') { 1013 h = (h << 4) + *p++; 1014 if ((g = h & 0xf0000000) != 0) 1015 h ^= g >> 24; 1016 h &= ~g; 1017 } 1018 return h; 1019 } 1020 1021 static int 1022 link_elf_lookup_symbol(linker_file_t lf, const char* name, c_linker_sym_t* sym) 1023 { 1024 elf_file_t ef = (elf_file_t) lf; 1025 unsigned long symnum; 1026 const Elf_Sym* symp; 1027 const char *strp; 1028 unsigned long hash; 1029 int i; 1030 1031 /* If we don't have a hash, bail. */ 1032 if (ef->buckets == NULL || ef->nbuckets == 0) { 1033 printf("link_elf_lookup_symbol: missing symbol hash table\n"); 1034 return ENOENT; 1035 } 1036 1037 /* First, search hashed global symbols */ 1038 hash = elf_hash(name); 1039 symnum = ef->buckets[hash % ef->nbuckets]; 1040 1041 while (symnum != STN_UNDEF) { 1042 if (symnum >= ef->nchains) { 1043 printf("link_elf_lookup_symbol: corrupt symbol table\n"); 1044 return ENOENT; 1045 } 1046 1047 symp = ef->symtab + symnum; 1048 if (symp->st_name == 0) { 1049 printf("link_elf_lookup_symbol: corrupt symbol table\n"); 1050 return ENOENT; 1051 } 1052 1053 strp = ef->strtab + symp->st_name; 1054 1055 if (strcmp(name, strp) == 0) { 1056 if (symp->st_shndx != SHN_UNDEF || 1057 (symp->st_value != 0 && 1058 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) { 1059 *sym = (c_linker_sym_t) symp; 1060 return 0; 1061 } else 1062 return ENOENT; 1063 } 1064 1065 symnum = ef->chains[symnum]; 1066 } 1067 1068 /* If we have not found it, look at the full table (if loaded) */ 1069 if (ef->symtab == ef->ddbsymtab) 1070 return ENOENT; 1071 1072 /* Exhaustive search */ 1073 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1074 strp = ef->ddbstrtab + symp->st_name; 1075 if (strcmp(name, strp) == 0) { 1076 if (symp->st_shndx != SHN_UNDEF || 1077 (symp->st_value != 0 && 1078 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) { 1079 *sym = (c_linker_sym_t) symp; 1080 return 0; 1081 } else 1082 return ENOENT; 1083 } 1084 } 1085 1086 return ENOENT; 1087 } 1088 1089 static int 1090 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, linker_symval_t* symval) 1091 { 1092 elf_file_t ef = (elf_file_t) lf; 1093 const Elf_Sym* es = (const Elf_Sym*) sym; 1094 1095 if (es >= ef->symtab && es < (ef->symtab + ef->nchains)) { 1096 symval->name = ef->strtab + es->st_name; 1097 symval->value = (caddr_t) ef->address + es->st_value; 1098 symval->size = es->st_size; 1099 return 0; 1100 } 1101 if (ef->symtab == ef->ddbsymtab) 1102 return ENOENT; 1103 if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) { 1104 symval->name = ef->ddbstrtab + es->st_name; 1105 symval->value = (caddr_t) ef->address + es->st_value; 1106 symval->size = es->st_size; 1107 return 0; 1108 } 1109 return ENOENT; 1110 } 1111 1112 static int 1113 link_elf_search_symbol(linker_file_t lf, caddr_t value, 1114 c_linker_sym_t* sym, long* diffp) 1115 { 1116 elf_file_t ef = (elf_file_t) lf; 1117 u_long off = (uintptr_t) (void *) value; 1118 u_long diff = off; 1119 u_long st_value; 1120 const Elf_Sym* es; 1121 const Elf_Sym* best = 0; 1122 int i; 1123 1124 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) { 1125 if (es->st_name == 0) 1126 continue; 1127 st_value = es->st_value + (uintptr_t) (void *) ef->address; 1128 if (off >= st_value) { 1129 if (off - st_value < diff) { 1130 diff = off - st_value; 1131 best = es; 1132 if (diff == 0) 1133 break; 1134 } else if (off - st_value == diff) { 1135 best = es; 1136 } 1137 } 1138 } 1139 if (best == 0) 1140 *diffp = off; 1141 else 1142 *diffp = diff; 1143 *sym = (c_linker_sym_t) best; 1144 1145 return 0; 1146 } 1147 1148 /* 1149 * Look up a linker set on an ELF system. 1150 */ 1151 static int 1152 link_elf_lookup_set(linker_file_t lf, const char *name, 1153 void ***startp, void ***stopp, int *countp) 1154 { 1155 c_linker_sym_t sym; 1156 linker_symval_t symval; 1157 char *setsym; 1158 void **start, **stop; 1159 int len, error = 0, count; 1160 1161 len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */ 1162 setsym = malloc(len, M_LINKER, M_WAITOK); 1163 if (setsym == NULL) 1164 return ENOMEM; 1165 1166 /* get address of first entry */ 1167 snprintf(setsym, len, "%s%s", "__start_set_", name); 1168 error = link_elf_lookup_symbol(lf, setsym, &sym); 1169 if (error) 1170 goto out; 1171 link_elf_symbol_values(lf, sym, &symval); 1172 if (symval.value == 0) { 1173 error = ESRCH; 1174 goto out; 1175 } 1176 start = (void **)symval.value; 1177 1178 /* get address of last entry */ 1179 snprintf(setsym, len, "%s%s", "__stop_set_", name); 1180 error = link_elf_lookup_symbol(lf, setsym, &sym); 1181 if (error) 1182 goto out; 1183 link_elf_symbol_values(lf, sym, &symval); 1184 if (symval.value == 0) { 1185 error = ESRCH; 1186 goto out; 1187 } 1188 stop = (void **)symval.value; 1189 1190 /* and the number of entries */ 1191 count = stop - start; 1192 1193 /* and copy out */ 1194 if (startp) 1195 *startp = start; 1196 if (stopp) 1197 *stopp = stop; 1198 if (countp) 1199 *countp = count; 1200 1201 out: 1202 free(setsym, M_LINKER); 1203 return error; 1204 } 1205 1206 static int 1207 link_elf_each_function_name(linker_file_t file, 1208 int (*callback)(const char *, void *), void *opaque) { 1209 elf_file_t ef = (elf_file_t)file; 1210 const Elf_Sym* symp; 1211 int i, error; 1212 1213 /* Exhaustive search */ 1214 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1215 if (symp->st_value != 0 && 1216 ELF_ST_TYPE(symp->st_info) == STT_FUNC) { 1217 error = callback(ef->ddbstrtab + symp->st_name, opaque); 1218 if (error) 1219 return (error); 1220 } 1221 } 1222 return (0); 1223 } 1224 1225 #ifdef __ia64__ 1226 /* 1227 * Each KLD has its own GP. The GP value for each load module is given by 1228 * DT_PLTGOT on ia64. We need GP to construct function descriptors, but 1229 * don't have direct access to the ELF file structure. The link_elf_get_gp() 1230 * function returns the GP given a pointer to a generic linker file struct. 1231 */ 1232 Elf_Addr 1233 link_elf_get_gp(linker_file_t lf) 1234 { 1235 elf_file_t ef = (elf_file_t)lf; 1236 return (Elf_Addr)ef->got; 1237 } 1238 #endif 1239 1240 const Elf_Sym * 1241 elf_get_sym(linker_file_t lf, Elf_Size symidx) 1242 { 1243 elf_file_t ef = (elf_file_t)lf; 1244 1245 if (symidx >= ef->nchains) 1246 return (NULL); 1247 return (ef->symtab + symidx); 1248 } 1249 1250 const char * 1251 elf_get_symname(linker_file_t lf, Elf_Size symidx) 1252 { 1253 elf_file_t ef = (elf_file_t)lf; 1254 const Elf_Sym *sym; 1255 1256 if (symidx >= ef->nchains) 1257 return (NULL); 1258 sym = ef->symtab + symidx; 1259 return (ef->strtab + sym->st_name); 1260 } 1261 1262 /* 1263 * Symbol lookup function that can be used when the symbol index is known (ie 1264 * in relocations). It uses the symbol index instead of doing a fully fledged 1265 * hash table based lookup when such is valid. For example for local symbols. 1266 * This is not only more efficient, it's also more correct. It's not always 1267 * the case that the symbol can be found through the hash table. 1268 */ 1269 static Elf_Addr 1270 elf_lookup(linker_file_t lf, Elf_Size symidx, int deps) 1271 { 1272 elf_file_t ef = (elf_file_t)lf; 1273 const Elf_Sym *sym; 1274 const char *symbol; 1275 1276 /* Don't even try to lookup the symbol if the index is bogus. */ 1277 if (symidx >= ef->nchains) 1278 return (0); 1279 1280 sym = ef->symtab + symidx; 1281 1282 /* 1283 * Don't do a full lookup when the symbol is local. It may even 1284 * fail because it may not be found through the hash table. 1285 */ 1286 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) { 1287 /* Force lookup failure when we have an insanity. */ 1288 if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0) 1289 return (0); 1290 return ((Elf_Addr)ef->address + sym->st_value); 1291 } 1292 1293 /* 1294 * XXX we can avoid doing a hash table based lookup for global 1295 * symbols as well. This however is not always valid, so we'll 1296 * just do it the hard way for now. Performance tweaks can 1297 * always be added. 1298 */ 1299 1300 symbol = ef->strtab + sym->st_name; 1301 1302 /* Force a lookup failure if the symbol name is bogus. */ 1303 if (*symbol == 0) 1304 return (0); 1305 1306 return ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps)); 1307 } 1308 1309 static void 1310 link_elf_reloc_local(linker_file_t lf) 1311 { 1312 const Elf_Rel *rellim; 1313 const Elf_Rel *rel; 1314 const Elf_Rela *relalim; 1315 const Elf_Rela *rela; 1316 elf_file_t ef = (elf_file_t)lf; 1317 1318 /* Perform relocations without addend if there are any: */ 1319 if ((rel = ef->rel) != NULL) { 1320 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize); 1321 while (rel < rellim) { 1322 elf_reloc_local(lf, (Elf_Addr)ef->address, rel, ELF_RELOC_REL, 1323 elf_lookup); 1324 rel++; 1325 } 1326 } 1327 1328 /* Perform relocations with addend if there are any: */ 1329 if ((rela = ef->rela) != NULL) { 1330 relalim = (const Elf_Rela *)((const char *)ef->rela + ef->relasize); 1331 while (rela < relalim) { 1332 elf_reloc_local(lf, (Elf_Addr)ef->address, rela, ELF_RELOC_RELA, 1333 elf_lookup); 1334 rela++; 1335 } 1336 } 1337 } 1338