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