1 /*- 2 * Copyright (c) 1998 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 * $FreeBSD: src/sys/kern/link_elf.c,v 1.24 1999/12/24 15:33:36 bde Exp $ 27 * $DragonFly: src/sys/kern/link_elf.c,v 1.15 2004/11/12 00:09:23 dillon Exp $ 28 */ 29 30 #include <sys/param.h> 31 #include <sys/kernel.h> 32 #include <sys/systm.h> 33 #include <sys/malloc.h> 34 #include <sys/proc.h> 35 #include <sys/nlookup.h> 36 #include <sys/fcntl.h> 37 #include <sys/vnode.h> 38 #include <sys/linker.h> 39 #include <machine/elf.h> 40 41 #include <vm/vm.h> 42 #include <vm/vm_param.h> 43 #include <vm/vm_zone.h> 44 #include <sys/lock.h> 45 #ifdef SPARSE_MAPPING 46 #include <vm/vm_object.h> 47 #include <vm/vm_kern.h> 48 #include <vm/vm_extern.h> 49 #endif 50 #include <vm/pmap.h> 51 #include <vm/vm_map.h> 52 53 static int link_elf_load_module(const char*, linker_file_t*); 54 static int link_elf_load_file(const char*, linker_file_t*); 55 static int link_elf_lookup_symbol(linker_file_t, const char*, 56 c_linker_sym_t*); 57 static int link_elf_symbol_values(linker_file_t, c_linker_sym_t, linker_symval_t*); 58 static int link_elf_search_symbol(linker_file_t, caddr_t value, 59 c_linker_sym_t* sym, long* diffp); 60 61 static void link_elf_unload_file(linker_file_t); 62 static void link_elf_unload_module(linker_file_t); 63 static int link_elf_lookup_set(linker_file_t, const char *, 64 void ***, void ***, int *); 65 66 67 static struct linker_class_ops link_elf_class_ops = { 68 link_elf_load_module, 69 }; 70 71 static struct linker_file_ops link_elf_file_ops = { 72 link_elf_lookup_symbol, 73 link_elf_symbol_values, 74 link_elf_search_symbol, 75 link_elf_unload_file, 76 link_elf_lookup_set 77 }; 78 79 static struct linker_file_ops link_elf_module_ops = { 80 link_elf_lookup_symbol, 81 link_elf_symbol_values, 82 link_elf_search_symbol, 83 link_elf_unload_module, 84 link_elf_lookup_set 85 }; 86 typedef struct elf_file { 87 caddr_t address; /* Relocation address */ 88 #ifdef SPARSE_MAPPING 89 vm_object_t object; /* VM object to hold file pages */ 90 #endif 91 const Elf_Dyn* dynamic; /* Symbol table etc. */ 92 Elf_Off nbuckets; /* DT_HASH info */ 93 Elf_Off nchains; 94 const Elf_Off* buckets; 95 const Elf_Off* chains; 96 caddr_t hash; 97 caddr_t strtab; /* DT_STRTAB */ 98 int strsz; /* DT_STRSZ */ 99 const Elf_Sym* symtab; /* DT_SYMTAB */ 100 Elf_Addr* got; /* DT_PLTGOT */ 101 const Elf_Rel* pltrel; /* DT_JMPREL */ 102 int pltrelsize; /* DT_PLTRELSZ */ 103 const Elf_Rela* pltrela; /* DT_JMPREL */ 104 int pltrelasize; /* DT_PLTRELSZ */ 105 const Elf_Rel* rel; /* DT_REL */ 106 int relsize; /* DT_RELSZ */ 107 const Elf_Rela* rela; /* DT_RELA */ 108 int relasize; /* DT_RELASZ */ 109 caddr_t modptr; 110 const Elf_Sym* ddbsymtab; /* The symbol table we are using */ 111 long ddbsymcnt; /* Number of symbols */ 112 caddr_t ddbstrtab; /* String table */ 113 long ddbstrcnt; /* number of bytes in string table */ 114 caddr_t symbase; /* malloc'ed symbold base */ 115 caddr_t strbase; /* malloc'ed string base */ 116 } *elf_file_t; 117 118 static int parse_dynamic(linker_file_t lf); 119 static int load_dependancies(linker_file_t lf); 120 static int relocate_file(linker_file_t lf); 121 static int parse_module_symbols(linker_file_t lf); 122 123 /* 124 * The kernel symbol table starts here. 125 */ 126 extern struct _dynamic _DYNAMIC; 127 128 static void 129 link_elf_init(void* arg) 130 { 131 Elf_Dyn *dp; 132 caddr_t modptr, baseptr, sizeptr; 133 elf_file_t ef; 134 char *modname; 135 136 #if ELF_TARG_CLASS == ELFCLASS32 137 linker_add_class("elf32", NULL, &link_elf_class_ops); 138 #else 139 linker_add_class("elf64", NULL, &link_elf_class_ops); 140 #endif 141 142 dp = (Elf_Dyn*) &_DYNAMIC; 143 if (dp) { 144 ef = malloc(sizeof(struct elf_file), M_LINKER, M_NOWAIT); 145 if (ef == NULL) 146 panic("link_elf_init: Can't create linker structures for kernel"); 147 bzero(ef, sizeof(*ef)); 148 149 ef->address = 0; 150 #ifdef SPARSE_MAPPING 151 ef->object = 0; 152 #endif 153 ef->dynamic = dp; 154 modname = NULL; 155 modptr = preload_search_by_type("elf kernel"); 156 if (modptr) 157 modname = (char *)preload_search_info(modptr, MODINFO_NAME); 158 if (modname == NULL) 159 modname = "kernel"; 160 linker_kernel_file = linker_make_file(modname, ef, &link_elf_file_ops); 161 if (linker_kernel_file == NULL) 162 panic("link_elf_init: Can't create linker structures for kernel"); 163 parse_dynamic(linker_kernel_file); 164 linker_kernel_file->address = (caddr_t) KERNBASE; 165 linker_kernel_file->size = -(intptr_t)linker_kernel_file->address; 166 167 if (modptr) { 168 ef->modptr = modptr; 169 baseptr = preload_search_info(modptr, MODINFO_ADDR); 170 if (baseptr) 171 linker_kernel_file->address = *(caddr_t *)baseptr; 172 sizeptr = preload_search_info(modptr, MODINFO_SIZE); 173 if (sizeptr) 174 linker_kernel_file->size = *(size_t *)sizeptr; 175 } 176 (void)parse_module_symbols(linker_kernel_file); 177 linker_current_file = linker_kernel_file; 178 linker_kernel_file->flags |= LINKER_FILE_LINKED; 179 } 180 } 181 182 SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_SECOND, link_elf_init, 0); 183 184 static int 185 parse_module_symbols(linker_file_t lf) 186 { 187 elf_file_t ef = lf->priv; 188 caddr_t pointer; 189 caddr_t ssym, esym, base; 190 caddr_t strtab; 191 int strcnt; 192 Elf_Sym* symtab; 193 int symcnt; 194 195 if (ef->modptr == NULL) 196 return 0; 197 pointer = preload_search_info(ef->modptr, MODINFO_METADATA|MODINFOMD_SSYM); 198 if (pointer == NULL) 199 return 0; 200 ssym = *(caddr_t *)pointer; 201 pointer = preload_search_info(ef->modptr, MODINFO_METADATA|MODINFOMD_ESYM); 202 if (pointer == NULL) 203 return 0; 204 esym = *(caddr_t *)pointer; 205 206 base = ssym; 207 208 symcnt = *(long *)base; 209 base += sizeof(long); 210 symtab = (Elf_Sym *)base; 211 base += roundup(symcnt, sizeof(long)); 212 213 if (base > esym || base < ssym) { 214 printf("Symbols are corrupt!\n"); 215 return EINVAL; 216 } 217 218 strcnt = *(long *)base; 219 base += sizeof(long); 220 strtab = base; 221 base += roundup(strcnt, sizeof(long)); 222 223 if (base > esym || base < ssym) { 224 printf("Symbols are corrupt!\n"); 225 return EINVAL; 226 } 227 228 ef->ddbsymtab = symtab; 229 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym); 230 ef->ddbstrtab = strtab; 231 ef->ddbstrcnt = strcnt; 232 233 return 0; 234 } 235 236 static int 237 parse_dynamic(linker_file_t lf) 238 { 239 elf_file_t ef = lf->priv; 240 const Elf_Dyn *dp; 241 int plttype = DT_REL; 242 243 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) { 244 switch (dp->d_tag) { 245 case DT_HASH: 246 { 247 /* From src/libexec/rtld-elf/rtld.c */ 248 const Elf_Off *hashtab = (const Elf_Off *) 249 (ef->address + dp->d_un.d_ptr); 250 ef->nbuckets = hashtab[0]; 251 ef->nchains = hashtab[1]; 252 ef->buckets = hashtab + 2; 253 ef->chains = ef->buckets + ef->nbuckets; 254 break; 255 } 256 case DT_STRTAB: 257 ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr); 258 break; 259 case DT_STRSZ: 260 ef->strsz = dp->d_un.d_val; 261 break; 262 case DT_SYMTAB: 263 ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr); 264 break; 265 case DT_SYMENT: 266 if (dp->d_un.d_val != sizeof(Elf_Sym)) 267 return ENOEXEC; 268 break; 269 case DT_PLTGOT: 270 ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr); 271 break; 272 case DT_REL: 273 ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr); 274 break; 275 case DT_RELSZ: 276 ef->relsize = dp->d_un.d_val; 277 break; 278 case DT_RELENT: 279 if (dp->d_un.d_val != sizeof(Elf_Rel)) 280 return ENOEXEC; 281 break; 282 case DT_JMPREL: 283 ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr); 284 break; 285 case DT_PLTRELSZ: 286 ef->pltrelsize = dp->d_un.d_val; 287 break; 288 case DT_RELA: 289 ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr); 290 break; 291 case DT_RELASZ: 292 ef->relasize = dp->d_un.d_val; 293 break; 294 case DT_RELAENT: 295 if (dp->d_un.d_val != sizeof(Elf_Rela)) 296 return ENOEXEC; 297 break; 298 case DT_PLTREL: 299 plttype = dp->d_un.d_val; 300 if (plttype != DT_REL && plttype != DT_RELA) 301 return ENOEXEC; 302 break; 303 } 304 } 305 306 if (plttype == DT_RELA) { 307 ef->pltrela = (const Elf_Rela *) ef->pltrel; 308 ef->pltrel = NULL; 309 ef->pltrelasize = ef->pltrelsize; 310 ef->pltrelsize = 0; 311 } 312 313 ef->ddbsymtab = ef->symtab; 314 ef->ddbsymcnt = ef->nchains; 315 ef->ddbstrtab = ef->strtab; 316 ef->ddbstrcnt = ef->strsz; 317 318 return 0; 319 } 320 321 static void 322 link_elf_error(const char *s) 323 { 324 printf("kldload: %s\n", s); 325 } 326 327 static int 328 link_elf_load_module(const char *filename, linker_file_t *result) 329 { 330 caddr_t modptr, baseptr, sizeptr, dynptr; 331 char *type; 332 elf_file_t ef; 333 linker_file_t lf; 334 int error; 335 vm_offset_t dp; 336 337 /* 338 * Look to see if we have the module preloaded. 339 */ 340 modptr = preload_search_by_name(filename); 341 if (modptr == NULL) 342 return (link_elf_load_file(filename, result)); 343 344 /* It's preloaded, check we can handle it and collect information */ 345 type = (char *)preload_search_info(modptr, MODINFO_TYPE); 346 baseptr = preload_search_info(modptr, MODINFO_ADDR); 347 sizeptr = preload_search_info(modptr, MODINFO_SIZE); 348 dynptr = preload_search_info(modptr, MODINFO_METADATA|MODINFOMD_DYNAMIC); 349 if (type == NULL || strcmp(type, "elf module") != 0) 350 return (EFTYPE); 351 if (baseptr == NULL || sizeptr == NULL || dynptr == NULL) 352 return (EINVAL); 353 354 ef = malloc(sizeof(struct elf_file), M_LINKER, M_WAITOK); 355 if (ef == NULL) 356 return (ENOMEM); 357 bzero(ef, sizeof(*ef)); 358 ef->modptr = modptr; 359 ef->address = *(caddr_t *)baseptr; 360 #ifdef SPARSE_MAPPING 361 ef->object = 0; 362 #endif 363 dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr; 364 ef->dynamic = (Elf_Dyn *)dp; 365 lf = linker_make_file(filename, ef, &link_elf_module_ops); 366 if (lf == NULL) { 367 free(ef, M_LINKER); 368 return ENOMEM; 369 } 370 lf->address = ef->address; 371 lf->size = *(size_t *)sizeptr; 372 373 error = parse_dynamic(lf); 374 if (error) { 375 linker_file_unload(lf); 376 return error; 377 } 378 error = load_dependancies(lf); 379 if (error) { 380 linker_file_unload(lf); 381 return error; 382 } 383 error = relocate_file(lf); 384 if (error) { 385 linker_file_unload(lf); 386 return error; 387 } 388 (void)parse_module_symbols(lf); 389 lf->flags |= LINKER_FILE_LINKED; 390 *result = lf; 391 return (0); 392 } 393 394 static int 395 link_elf_load_file(const char* filename, linker_file_t* result) 396 { 397 struct nlookupdata nd; 398 struct thread *td = curthread; /* XXX */ 399 struct proc *p = td->td_proc; 400 struct vnode *vp; 401 Elf_Ehdr *hdr; 402 caddr_t firstpage; 403 int nbytes, i; 404 Elf_Phdr *phdr; 405 Elf_Phdr *phlimit; 406 Elf_Phdr *segs[2]; 407 int nsegs; 408 Elf_Phdr *phdyn; 409 Elf_Phdr *phphdr; 410 caddr_t mapbase; 411 size_t mapsize; 412 Elf_Off base_offset; 413 Elf_Addr base_vaddr; 414 Elf_Addr base_vlimit; 415 int error = 0; 416 int resid; 417 elf_file_t ef; 418 linker_file_t lf; 419 char *pathname; 420 Elf_Shdr *shdr; 421 int symtabindex; 422 int symstrindex; 423 int symcnt; 424 int strcnt; 425 426 KKASSERT(p != NULL); 427 if (p->p_ucred == NULL) { 428 printf("link_elf_load_file: cannot load '%s' from filesystem" 429 " this early\n", filename); 430 return ENOENT; 431 } 432 shdr = NULL; 433 lf = NULL; 434 pathname = linker_search_path(filename); 435 if (pathname == NULL) 436 return ENOENT; 437 438 error = nlookup_init(&nd, pathname, UIO_SYSSPACE, NLC_FOLLOW|NLC_LOCKVP); 439 if (error == 0) 440 error = vn_open(&nd, NULL, FREAD, 0); 441 free(pathname, M_LINKER); 442 if (error) { 443 nlookup_done(&nd); 444 return error; 445 } 446 vp = nd.nl_open_vp; 447 nd.nl_open_vp = NULL; 448 nlookup_done(&nd); 449 450 /* 451 * Read the elf header from the file. 452 */ 453 firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK); 454 if (firstpage == NULL) { 455 error = ENOMEM; 456 goto out; 457 } 458 hdr = (Elf_Ehdr *)firstpage; 459 error = vn_rdwr(UIO_READ, vp, firstpage, PAGE_SIZE, 0, 460 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, td); 461 nbytes = PAGE_SIZE - resid; 462 if (error) 463 goto out; 464 465 if (!IS_ELF(*hdr)) { 466 error = ENOEXEC; 467 goto out; 468 } 469 470 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS 471 || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) { 472 link_elf_error("Unsupported file layout"); 473 error = ENOEXEC; 474 goto out; 475 } 476 if (hdr->e_ident[EI_VERSION] != EV_CURRENT 477 || hdr->e_version != EV_CURRENT) { 478 link_elf_error("Unsupported file version"); 479 error = ENOEXEC; 480 goto out; 481 } 482 if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) { 483 link_elf_error("Unsupported file type"); 484 error = ENOEXEC; 485 goto out; 486 } 487 if (hdr->e_machine != ELF_TARG_MACH) { 488 link_elf_error("Unsupported machine"); 489 error = ENOEXEC; 490 goto out; 491 } 492 493 /* 494 * We rely on the program header being in the first page. This is 495 * not strictly required by the ABI specification, but it seems to 496 * always true in practice. And, it simplifies things considerably. 497 */ 498 if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) && 499 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) && 500 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes))) 501 link_elf_error("Unreadable program headers"); 502 503 /* 504 * Scan the program header entries, and save key information. 505 * 506 * We rely on there being exactly two load segments, text and data, 507 * in that order. 508 */ 509 phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff); 510 phlimit = phdr + hdr->e_phnum; 511 nsegs = 0; 512 phdyn = NULL; 513 phphdr = NULL; 514 while (phdr < phlimit) { 515 switch (phdr->p_type) { 516 517 case PT_LOAD: 518 if (nsegs == 2) { 519 link_elf_error("Too many sections"); 520 error = ENOEXEC; 521 goto out; 522 } 523 segs[nsegs] = phdr; 524 ++nsegs; 525 break; 526 527 case PT_PHDR: 528 phphdr = phdr; 529 break; 530 531 case PT_DYNAMIC: 532 phdyn = phdr; 533 break; 534 } 535 536 ++phdr; 537 } 538 if (phdyn == NULL) { 539 link_elf_error("Object is not dynamically-linked"); 540 error = ENOEXEC; 541 goto out; 542 } 543 544 /* 545 * Allocate the entire address space of the object, to stake out our 546 * contiguous region, and to establish the base address for relocation. 547 */ 548 base_offset = trunc_page(segs[0]->p_offset); 549 base_vaddr = trunc_page(segs[0]->p_vaddr); 550 base_vlimit = round_page(segs[1]->p_vaddr + segs[1]->p_memsz); 551 mapsize = base_vlimit - base_vaddr; 552 553 ef = malloc(sizeof(struct elf_file), M_LINKER, M_WAITOK); 554 bzero(ef, sizeof(*ef)); 555 #ifdef SPARSE_MAPPING 556 ef->object = vm_object_allocate(OBJT_DEFAULT, mapsize >> PAGE_SHIFT); 557 if (ef->object == NULL) { 558 free(ef, M_LINKER); 559 error = ENOMEM; 560 goto out; 561 } 562 vm_object_reference(ef->object); 563 ef->address = (caddr_t) vm_map_min(kernel_map); 564 error = vm_map_find(kernel_map, ef->object, 0, 565 (vm_offset_t *) &ef->address, 566 mapsize, 1, 567 VM_PROT_ALL, VM_PROT_ALL, 0); 568 if (error) { 569 vm_object_deallocate(ef->object); 570 free(ef, M_LINKER); 571 goto out; 572 } 573 #else 574 ef->address = malloc(mapsize, M_LINKER, M_WAITOK); 575 #endif 576 mapbase = ef->address; 577 578 /* 579 * Read the text and data sections and zero the bss. 580 */ 581 for (i = 0; i < 2; i++) { 582 caddr_t segbase = mapbase + segs[i]->p_vaddr - base_vaddr; 583 error = vn_rdwr(UIO_READ, vp, 584 segbase, segs[i]->p_filesz, segs[i]->p_offset, 585 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, td); 586 if (error) { 587 #ifdef SPARSE_MAPPING 588 vm_map_remove(kernel_map, (vm_offset_t) ef->address, 589 (vm_offset_t) ef->address 590 + (ef->object->size << PAGE_SHIFT)); 591 vm_object_deallocate(ef->object); 592 #else 593 free(ef->address, M_LINKER); 594 #endif 595 free(ef, M_LINKER); 596 goto out; 597 } 598 bzero(segbase + segs[i]->p_filesz, 599 segs[i]->p_memsz - segs[i]->p_filesz); 600 601 #ifdef SPARSE_MAPPING 602 /* 603 * Wire down the pages 604 */ 605 vm_map_wire(kernel_map, 606 (vm_offset_t) segbase, 607 (vm_offset_t) segbase + segs[i]->p_memsz, 608 0); 609 #endif 610 } 611 612 ef->dynamic = (const Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr); 613 614 lf = linker_make_file(filename, ef, &link_elf_file_ops); 615 if (lf == NULL) { 616 #ifdef SPARSE_MAPPING 617 vm_map_remove(kernel_map, (vm_offset_t) ef->address, 618 (vm_offset_t) ef->address 619 + (ef->object->size << PAGE_SHIFT)); 620 vm_object_deallocate(ef->object); 621 #else 622 free(ef->address, M_LINKER); 623 #endif 624 free(ef, M_LINKER); 625 error = ENOMEM; 626 goto out; 627 } 628 lf->address = ef->address; 629 lf->size = mapsize; 630 631 error = parse_dynamic(lf); 632 if (error) 633 goto out; 634 error = load_dependancies(lf); 635 if (error) 636 goto out; 637 error = relocate_file(lf); 638 if (error) 639 goto out; 640 641 /* Try and load the symbol table if it's present. (you can strip it!) */ 642 nbytes = hdr->e_shnum * hdr->e_shentsize; 643 if (nbytes == 0 || hdr->e_shoff == 0) 644 goto nosyms; 645 shdr = malloc(nbytes, M_LINKER, M_WAITOK); 646 if (shdr == NULL) { 647 error = ENOMEM; 648 goto out; 649 } 650 bzero(shdr, nbytes); 651 error = vn_rdwr(UIO_READ, vp, 652 (caddr_t)shdr, nbytes, hdr->e_shoff, 653 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, td); 654 if (error) 655 goto out; 656 symtabindex = -1; 657 symstrindex = -1; 658 for (i = 0; i < hdr->e_shnum; i++) { 659 if (shdr[i].sh_type == SHT_SYMTAB) { 660 symtabindex = i; 661 symstrindex = shdr[i].sh_link; 662 } 663 } 664 if (symtabindex < 0 || symstrindex < 0) 665 goto nosyms; 666 667 symcnt = shdr[symtabindex].sh_size; 668 ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK); 669 strcnt = shdr[symstrindex].sh_size; 670 ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK); 671 672 if (ef->symbase == NULL || ef->strbase == NULL) { 673 error = ENOMEM; 674 goto out; 675 } 676 error = vn_rdwr(UIO_READ, vp, 677 ef->symbase, symcnt, shdr[symtabindex].sh_offset, 678 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, td); 679 if (error) 680 goto out; 681 error = vn_rdwr(UIO_READ, vp, 682 ef->strbase, strcnt, shdr[symstrindex].sh_offset, 683 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, td); 684 if (error) 685 goto out; 686 687 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym); 688 ef->ddbsymtab = (const Elf_Sym *)ef->symbase; 689 ef->ddbstrcnt = strcnt; 690 ef->ddbstrtab = ef->strbase; 691 692 lf->flags |= LINKER_FILE_LINKED; 693 694 nosyms: 695 696 *result = lf; 697 698 out: 699 if (error && lf) 700 linker_file_unload(lf); 701 if (shdr) 702 free(shdr, M_LINKER); 703 if (firstpage) 704 free(firstpage, M_LINKER); 705 VOP_UNLOCK(vp, 0, td); 706 vn_close(vp, FREAD, td); 707 708 return error; 709 } 710 711 static void 712 link_elf_unload_file(linker_file_t file) 713 { 714 elf_file_t ef = file->priv; 715 716 if (ef) { 717 #ifdef SPARSE_MAPPING 718 if (ef->object) { 719 vm_map_remove(kernel_map, (vm_offset_t) ef->address, 720 (vm_offset_t) ef->address 721 + (ef->object->size << PAGE_SHIFT)); 722 vm_object_deallocate(ef->object); 723 } 724 #else 725 if (ef->address) 726 free(ef->address, M_LINKER); 727 #endif 728 if (ef->symbase) 729 free(ef->symbase, M_LINKER); 730 if (ef->strbase) 731 free(ef->strbase, M_LINKER); 732 free(ef, M_LINKER); 733 } 734 } 735 736 static void 737 link_elf_unload_module(linker_file_t file) 738 { 739 elf_file_t ef = file->priv; 740 741 if (ef) 742 free(ef, M_LINKER); 743 if (file->filename) 744 preload_delete_name(file->filename); 745 } 746 747 static int 748 load_dependancies(linker_file_t lf) 749 { 750 elf_file_t ef = lf->priv; 751 linker_file_t lfdep; 752 char* name; 753 const Elf_Dyn *dp; 754 int error = 0; 755 756 /* 757 * All files are dependant on /kernel. 758 */ 759 if (linker_kernel_file) { 760 linker_kernel_file->refs++; 761 linker_file_add_dependancy(lf, linker_kernel_file); 762 } 763 764 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) { 765 if (dp->d_tag == DT_NEEDED) { 766 name = ef->strtab + dp->d_un.d_val; 767 768 error = linker_load_file(name, &lfdep); 769 if (error) 770 goto out; 771 error = linker_file_add_dependancy(lf, lfdep); 772 if (error) 773 goto out; 774 } 775 } 776 777 out: 778 return error; 779 } 780 781 static const char * 782 symbol_name(elf_file_t ef, Elf_Word r_info) 783 { 784 const Elf_Sym *ref; 785 786 if (ELF_R_SYM(r_info)) { 787 ref = ef->symtab + ELF_R_SYM(r_info); 788 return ef->strtab + ref->st_name; 789 } else 790 return NULL; 791 } 792 793 static int 794 relocate_file(linker_file_t lf) 795 { 796 elf_file_t ef = lf->priv; 797 const Elf_Rel *rellim; 798 const Elf_Rel *rel; 799 const Elf_Rela *relalim; 800 const Elf_Rela *rela; 801 const char *symname; 802 803 /* Perform relocations without addend if there are any: */ 804 rel = ef->rel; 805 if (rel) { 806 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize); 807 while (rel < rellim) { 808 symname = symbol_name(ef, rel->r_info); 809 if (elf_reloc(lf, rel, ELF_RELOC_REL, symname)) { 810 printf("link_elf: symbol %s undefined\n", symname); 811 return ENOENT; 812 } 813 rel++; 814 } 815 } 816 817 /* Perform relocations with addend if there are any: */ 818 rela = ef->rela; 819 if (rela) { 820 relalim = (const Elf_Rela *)((const char *)ef->rela + ef->relasize); 821 while (rela < relalim) { 822 symname = symbol_name(ef, rela->r_info); 823 if (elf_reloc(lf, rela, ELF_RELOC_RELA, symname)) { 824 printf("link_elf: symbol %s undefined\n", symname); 825 return ENOENT; 826 } 827 rela++; 828 } 829 } 830 831 /* Perform PLT relocations without addend if there are any: */ 832 rel = ef->pltrel; 833 if (rel) { 834 rellim = (const Elf_Rel *)((const char *)ef->pltrel + ef->pltrelsize); 835 while (rel < rellim) { 836 symname = symbol_name(ef, rel->r_info); 837 if (elf_reloc(lf, rel, ELF_RELOC_REL, symname)) { 838 printf("link_elf: symbol %s undefined\n", symname); 839 return ENOENT; 840 } 841 rel++; 842 } 843 } 844 845 /* Perform relocations with addend if there are any: */ 846 rela = ef->pltrela; 847 if (rela) { 848 relalim = (const Elf_Rela *)((const char *)ef->pltrela + ef->pltrelasize); 849 while (rela < relalim) { 850 symname = symbol_name(ef, rela->r_info); 851 if (elf_reloc(lf, rela, ELF_RELOC_RELA, symname)) { 852 printf("link_elf: symbol %s undefined\n", symname); 853 return ENOENT; 854 } 855 rela++; 856 } 857 } 858 859 return 0; 860 } 861 862 /* 863 * Hash function for symbol table lookup. Don't even think about changing 864 * this. It is specified by the System V ABI. 865 */ 866 static unsigned long 867 elf_hash(const char *name) 868 { 869 const unsigned char *p = (const unsigned char *) name; 870 unsigned long h = 0; 871 unsigned long g; 872 873 while (*p != '\0') { 874 h = (h << 4) + *p++; 875 if ((g = h & 0xf0000000) != 0) 876 h ^= g >> 24; 877 h &= ~g; 878 } 879 return h; 880 } 881 882 int 883 link_elf_lookup_symbol(linker_file_t lf, const char* name, c_linker_sym_t* sym) 884 { 885 elf_file_t ef = lf->priv; 886 unsigned long symnum; 887 const Elf_Sym* symp; 888 const char *strp; 889 unsigned long hash; 890 int i; 891 892 /* First, search hashed global symbols */ 893 hash = elf_hash(name); 894 symnum = ef->buckets[hash % ef->nbuckets]; 895 896 while (symnum != STN_UNDEF) { 897 if (symnum >= ef->nchains) { 898 printf("link_elf_lookup_symbol: corrupt symbol table\n"); 899 return ENOENT; 900 } 901 902 symp = ef->symtab + symnum; 903 if (symp->st_name == 0) { 904 printf("link_elf_lookup_symbol: corrupt symbol table\n"); 905 return ENOENT; 906 } 907 908 strp = ef->strtab + symp->st_name; 909 910 if (strcmp(name, strp) == 0) { 911 if (symp->st_shndx != SHN_UNDEF || 912 (symp->st_value != 0 && 913 ELF_ST_TYPE(symp->st_info) == STT_FUNC) 914 ) { 915 *sym = (c_linker_sym_t) symp; 916 return 0; 917 } else { 918 return ENOENT; 919 } 920 } 921 922 symnum = ef->chains[symnum]; 923 } 924 925 /* If we have not found it, look at the full table (if loaded) */ 926 if (ef->symtab == ef->ddbsymtab) 927 return ENOENT; 928 929 /* Exhaustive search */ 930 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 931 strp = ef->ddbstrtab + symp->st_name; 932 if (strcmp(name, strp) == 0) { 933 if (symp->st_shndx != SHN_UNDEF || 934 (symp->st_value != 0 && 935 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) { 936 *sym = (c_linker_sym_t) symp; 937 return 0; 938 } else { 939 return ENOENT; 940 } 941 } 942 } 943 return ENOENT; 944 } 945 946 static int 947 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, linker_symval_t* symval) 948 { 949 elf_file_t ef = lf->priv; 950 const Elf_Sym* es = (const Elf_Sym*) sym; 951 952 if (es >= ef->symtab && ((es - ef->symtab) < ef->nchains)) { 953 symval->name = ef->strtab + es->st_name; 954 symval->value = (caddr_t) ef->address + es->st_value; 955 symval->size = es->st_size; 956 return 0; 957 } 958 if (ef->symtab == ef->ddbsymtab) 959 return ENOENT; 960 if (es >= ef->ddbsymtab && ((es - ef->ddbsymtab) < ef->ddbsymcnt)) { 961 symval->name = ef->ddbstrtab + es->st_name; 962 symval->value = (caddr_t) ef->address + es->st_value; 963 symval->size = es->st_size; 964 return 0; 965 } 966 return ENOENT; 967 } 968 969 static int 970 link_elf_search_symbol(linker_file_t lf, caddr_t value, 971 c_linker_sym_t* sym, long* diffp) 972 { 973 elf_file_t ef = lf->priv; 974 u_long off = (uintptr_t) (void *) value; 975 u_long diff = off; 976 u_long st_value; 977 const Elf_Sym* es; 978 const Elf_Sym* best = 0; 979 int i; 980 981 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) { 982 if (es->st_name == 0) 983 continue; 984 st_value = es->st_value + (uintptr_t) (void *) ef->address; 985 if (off >= st_value) { 986 if (off - st_value < diff) { 987 diff = off - st_value; 988 best = es; 989 if (diff == 0) 990 break; 991 } else if (off - st_value == diff) { 992 best = es; 993 } 994 } 995 } 996 if (best == 0) 997 *diffp = off; 998 else 999 *diffp = diff; 1000 *sym = (c_linker_sym_t) best; 1001 1002 return 0; 1003 } 1004 1005 /* 1006 * Look up a linker set on an ELF system. 1007 */ 1008 static int 1009 link_elf_lookup_set(linker_file_t lf, const char *name, 1010 void ***startp, void ***stopp, int *countp) 1011 { 1012 c_linker_sym_t sym; 1013 linker_symval_t symval; 1014 char *setsym; 1015 void **start, **stop; 1016 int len, error = 0, count; 1017 1018 len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */ 1019 setsym = malloc(len, M_LINKER, M_WAITOK); 1020 if (setsym == NULL) 1021 return ENOMEM; 1022 1023 /* get address of first entry */ 1024 snprintf(setsym, len, "%s%s", "__start_set_", name); 1025 error = link_elf_lookup_symbol(lf, setsym, &sym); 1026 if (error) 1027 goto out; 1028 link_elf_symbol_values(lf, sym, &symval); 1029 if (symval.value == 0) { 1030 error = ESRCH; 1031 goto out; 1032 } 1033 start = (void **)symval.value; 1034 1035 /* get address of last entry */ 1036 snprintf(setsym, len, "%s%s", "__stop_set_", name); 1037 error = link_elf_lookup_symbol(lf, setsym, &sym); 1038 if (error) 1039 goto out; 1040 link_elf_symbol_values(lf, sym, &symval); 1041 if (symval.value == 0) { 1042 error = ESRCH; 1043 goto out; 1044 } 1045 stop = (void **)symval.value; 1046 1047 /* and the number of entries */ 1048 count = stop - start; 1049 1050 /* and copy out */ 1051 if (startp) 1052 *startp = start; 1053 if (stopp) 1054 *stopp = stop; 1055 if (countp) 1056 *countp = count; 1057 1058 out: 1059 free(setsym, M_LINKER); 1060 return error; 1061 } 1062 1063