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 1.9 2003/11/13 22:02:42 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/namei.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 #ifdef __ELF__ 132 Elf_Dyn *dp; 133 caddr_t modptr, baseptr, sizeptr; 134 elf_file_t ef; 135 char *modname; 136 #endif 137 138 #if ELF_TARG_CLASS == ELFCLASS32 139 linker_add_class("elf32", NULL, &link_elf_class_ops); 140 #else 141 linker_add_class("elf64", NULL, &link_elf_class_ops); 142 #endif 143 144 #ifdef __ELF__ 145 dp = (Elf_Dyn*) &_DYNAMIC; 146 if (dp) { 147 ef = malloc(sizeof(struct elf_file), M_LINKER, M_NOWAIT); 148 if (ef == NULL) 149 panic("link_elf_init: Can't create linker structures for kernel"); 150 bzero(ef, sizeof(*ef)); 151 152 ef->address = 0; 153 #ifdef SPARSE_MAPPING 154 ef->object = 0; 155 #endif 156 ef->dynamic = dp; 157 modname = NULL; 158 modptr = preload_search_by_type("elf kernel"); 159 if (modptr) 160 modname = (char *)preload_search_info(modptr, MODINFO_NAME); 161 if (modname == NULL) 162 modname = "kernel"; 163 linker_kernel_file = linker_make_file(modname, ef, &link_elf_file_ops); 164 if (linker_kernel_file == NULL) 165 panic("link_elf_init: Can't create linker structures for kernel"); 166 parse_dynamic(linker_kernel_file); 167 linker_kernel_file->address = (caddr_t) KERNBASE; 168 linker_kernel_file->size = -(intptr_t)linker_kernel_file->address; 169 170 if (modptr) { 171 ef->modptr = modptr; 172 baseptr = preload_search_info(modptr, MODINFO_ADDR); 173 if (baseptr) 174 linker_kernel_file->address = *(caddr_t *)baseptr; 175 sizeptr = preload_search_info(modptr, MODINFO_SIZE); 176 if (sizeptr) 177 linker_kernel_file->size = *(size_t *)sizeptr; 178 } 179 (void)parse_module_symbols(linker_kernel_file); 180 linker_current_file = linker_kernel_file; 181 linker_kernel_file->flags |= LINKER_FILE_LINKED; 182 } 183 #endif 184 } 185 186 SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_SECOND, link_elf_init, 0); 187 188 static int 189 parse_module_symbols(linker_file_t lf) 190 { 191 elf_file_t ef = lf->priv; 192 caddr_t pointer; 193 caddr_t ssym, esym, base; 194 caddr_t strtab; 195 int strcnt; 196 Elf_Sym* symtab; 197 int symcnt; 198 199 if (ef->modptr == NULL) 200 return 0; 201 pointer = preload_search_info(ef->modptr, MODINFO_METADATA|MODINFOMD_SSYM); 202 if (pointer == NULL) 203 return 0; 204 ssym = *(caddr_t *)pointer; 205 pointer = preload_search_info(ef->modptr, MODINFO_METADATA|MODINFOMD_ESYM); 206 if (pointer == NULL) 207 return 0; 208 esym = *(caddr_t *)pointer; 209 210 base = ssym; 211 212 symcnt = *(long *)base; 213 base += sizeof(long); 214 symtab = (Elf_Sym *)base; 215 base += roundup(symcnt, sizeof(long)); 216 217 if (base > esym || base < ssym) { 218 printf("Symbols are corrupt!\n"); 219 return EINVAL; 220 } 221 222 strcnt = *(long *)base; 223 base += sizeof(long); 224 strtab = base; 225 base += roundup(strcnt, sizeof(long)); 226 227 if (base > esym || base < ssym) { 228 printf("Symbols are corrupt!\n"); 229 return EINVAL; 230 } 231 232 ef->ddbsymtab = symtab; 233 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym); 234 ef->ddbstrtab = strtab; 235 ef->ddbstrcnt = strcnt; 236 237 return 0; 238 } 239 240 static int 241 parse_dynamic(linker_file_t lf) 242 { 243 elf_file_t ef = lf->priv; 244 const Elf_Dyn *dp; 245 int plttype = DT_REL; 246 247 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) { 248 switch (dp->d_tag) { 249 case DT_HASH: 250 { 251 /* From src/libexec/rtld-elf/rtld.c */ 252 const Elf_Off *hashtab = (const Elf_Off *) 253 (ef->address + dp->d_un.d_ptr); 254 ef->nbuckets = hashtab[0]; 255 ef->nchains = hashtab[1]; 256 ef->buckets = hashtab + 2; 257 ef->chains = ef->buckets + ef->nbuckets; 258 break; 259 } 260 case DT_STRTAB: 261 ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr); 262 break; 263 case DT_STRSZ: 264 ef->strsz = dp->d_un.d_val; 265 break; 266 case DT_SYMTAB: 267 ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr); 268 break; 269 case DT_SYMENT: 270 if (dp->d_un.d_val != sizeof(Elf_Sym)) 271 return ENOEXEC; 272 break; 273 case DT_PLTGOT: 274 ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr); 275 break; 276 case DT_REL: 277 ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr); 278 break; 279 case DT_RELSZ: 280 ef->relsize = dp->d_un.d_val; 281 break; 282 case DT_RELENT: 283 if (dp->d_un.d_val != sizeof(Elf_Rel)) 284 return ENOEXEC; 285 break; 286 case DT_JMPREL: 287 ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr); 288 break; 289 case DT_PLTRELSZ: 290 ef->pltrelsize = dp->d_un.d_val; 291 break; 292 case DT_RELA: 293 ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr); 294 break; 295 case DT_RELASZ: 296 ef->relasize = dp->d_un.d_val; 297 break; 298 case DT_RELAENT: 299 if (dp->d_un.d_val != sizeof(Elf_Rela)) 300 return ENOEXEC; 301 break; 302 case DT_PLTREL: 303 plttype = dp->d_un.d_val; 304 if (plttype != DT_REL && plttype != DT_RELA) 305 return ENOEXEC; 306 break; 307 } 308 } 309 310 if (plttype == DT_RELA) { 311 ef->pltrela = (const Elf_Rela *) ef->pltrel; 312 ef->pltrel = NULL; 313 ef->pltrelasize = ef->pltrelsize; 314 ef->pltrelsize = 0; 315 } 316 317 ef->ddbsymtab = ef->symtab; 318 ef->ddbsymcnt = ef->nchains; 319 ef->ddbstrtab = ef->strtab; 320 ef->ddbstrcnt = ef->strsz; 321 322 return 0; 323 } 324 325 static void 326 link_elf_error(const char *s) 327 { 328 printf("kldload: %s\n", s); 329 } 330 331 static int 332 link_elf_load_module(const char *filename, linker_file_t *result) 333 { 334 caddr_t modptr, baseptr, sizeptr, dynptr; 335 char *type; 336 elf_file_t ef; 337 linker_file_t lf; 338 int error; 339 vm_offset_t dp; 340 341 /* Look to see if we have the module preloaded */ 342 modptr = preload_search_by_name(filename); 343 if (modptr == NULL) 344 return (link_elf_load_file(filename, result)); 345 346 /* It's preloaded, check we can handle it and collect information */ 347 type = (char *)preload_search_info(modptr, MODINFO_TYPE); 348 baseptr = preload_search_info(modptr, MODINFO_ADDR); 349 sizeptr = preload_search_info(modptr, MODINFO_SIZE); 350 dynptr = preload_search_info(modptr, MODINFO_METADATA|MODINFOMD_DYNAMIC); 351 if (type == NULL || strcmp(type, "elf module") != 0) 352 return (EFTYPE); 353 if (baseptr == NULL || sizeptr == NULL || dynptr == NULL) 354 return (EINVAL); 355 356 ef = malloc(sizeof(struct elf_file), M_LINKER, M_WAITOK); 357 if (ef == NULL) 358 return (ENOMEM); 359 bzero(ef, sizeof(*ef)); 360 ef->modptr = modptr; 361 ef->address = *(caddr_t *)baseptr; 362 #ifdef SPARSE_MAPPING 363 ef->object = 0; 364 #endif 365 dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr; 366 ef->dynamic = (Elf_Dyn *)dp; 367 lf = linker_make_file(filename, ef, &link_elf_module_ops); 368 if (lf == NULL) { 369 free(ef, M_LINKER); 370 return ENOMEM; 371 } 372 lf->address = ef->address; 373 lf->size = *(size_t *)sizeptr; 374 375 error = parse_dynamic(lf); 376 if (error) { 377 linker_file_unload(lf); 378 return error; 379 } 380 error = load_dependancies(lf); 381 if (error) { 382 linker_file_unload(lf); 383 return error; 384 } 385 error = relocate_file(lf); 386 if (error) { 387 linker_file_unload(lf); 388 return error; 389 } 390 (void)parse_module_symbols(lf); 391 lf->flags |= LINKER_FILE_LINKED; 392 *result = lf; 393 return (0); 394 } 395 396 static int 397 link_elf_load_file(const char* filename, linker_file_t* result) 398 { 399 struct nameidata nd; 400 struct thread *td = curthread; /* XXX */ 401 struct proc *p = td->td_proc; 402 Elf_Ehdr *hdr; 403 caddr_t firstpage; 404 int nbytes, i; 405 Elf_Phdr *phdr; 406 Elf_Phdr *phlimit; 407 Elf_Phdr *segs[2]; 408 int nsegs; 409 Elf_Phdr *phdyn; 410 Elf_Phdr *phphdr; 411 caddr_t mapbase; 412 size_t mapsize; 413 Elf_Off base_offset; 414 Elf_Addr base_vaddr; 415 Elf_Addr base_vlimit; 416 int error = 0; 417 int resid; 418 elf_file_t ef; 419 linker_file_t lf; 420 char *pathname; 421 Elf_Shdr *shdr; 422 int symtabindex; 423 int symstrindex; 424 int symcnt; 425 int strcnt; 426 427 KKASSERT(p != NULL); 428 if (p->p_ucred == NULL) { 429 printf("link_elf_load_file: cannot load '%s' from filesystem" 430 " this early\n", filename); 431 return ENOENT; 432 } 433 shdr = NULL; 434 lf = NULL; 435 pathname = linker_search_path(filename); 436 if (pathname == NULL) 437 return ENOENT; 438 439 NDINIT(&nd, NAMEI_LOOKUP, CNP_FOLLOW, UIO_SYSSPACE, pathname, td); 440 error = vn_open(&nd, FREAD, 0); 441 free(pathname, M_LINKER); 442 if (error) 443 return error; 444 NDFREE(&nd, NDF_ONLY_PNBUF); 445 446 /* 447 * Read the elf header from the file. 448 */ 449 firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK); 450 if (firstpage == NULL) { 451 error = ENOMEM; 452 goto out; 453 } 454 hdr = (Elf_Ehdr *)firstpage; 455 error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0, 456 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, td); 457 nbytes = PAGE_SIZE - resid; 458 if (error) 459 goto out; 460 461 if (!IS_ELF(*hdr)) { 462 error = ENOEXEC; 463 goto out; 464 } 465 466 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS 467 || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) { 468 link_elf_error("Unsupported file layout"); 469 error = ENOEXEC; 470 goto out; 471 } 472 if (hdr->e_ident[EI_VERSION] != EV_CURRENT 473 || hdr->e_version != EV_CURRENT) { 474 link_elf_error("Unsupported file version"); 475 error = ENOEXEC; 476 goto out; 477 } 478 if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) { 479 link_elf_error("Unsupported file type"); 480 error = ENOEXEC; 481 goto out; 482 } 483 if (hdr->e_machine != ELF_TARG_MACH) { 484 link_elf_error("Unsupported machine"); 485 error = ENOEXEC; 486 goto out; 487 } 488 489 /* 490 * We rely on the program header being in the first page. This is 491 * not strictly required by the ABI specification, but it seems to 492 * always true in practice. And, it simplifies things considerably. 493 */ 494 if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) && 495 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) && 496 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes))) 497 link_elf_error("Unreadable program headers"); 498 499 /* 500 * Scan the program header entries, and save key information. 501 * 502 * We rely on there being exactly two load segments, text and data, 503 * in that order. 504 */ 505 phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff); 506 phlimit = phdr + hdr->e_phnum; 507 nsegs = 0; 508 phdyn = NULL; 509 phphdr = NULL; 510 while (phdr < phlimit) { 511 switch (phdr->p_type) { 512 513 case PT_LOAD: 514 if (nsegs == 2) { 515 link_elf_error("Too many sections"); 516 error = ENOEXEC; 517 goto out; 518 } 519 segs[nsegs] = phdr; 520 ++nsegs; 521 break; 522 523 case PT_PHDR: 524 phphdr = phdr; 525 break; 526 527 case PT_DYNAMIC: 528 phdyn = phdr; 529 break; 530 } 531 532 ++phdr; 533 } 534 if (phdyn == NULL) { 535 link_elf_error("Object is not dynamically-linked"); 536 error = ENOEXEC; 537 goto out; 538 } 539 540 /* 541 * Allocate the entire address space of the object, to stake out our 542 * contiguous region, and to establish the base address for relocation. 543 */ 544 base_offset = trunc_page(segs[0]->p_offset); 545 base_vaddr = trunc_page(segs[0]->p_vaddr); 546 base_vlimit = round_page(segs[1]->p_vaddr + segs[1]->p_memsz); 547 mapsize = base_vlimit - base_vaddr; 548 549 ef = malloc(sizeof(struct elf_file), M_LINKER, M_WAITOK); 550 bzero(ef, sizeof(*ef)); 551 #ifdef SPARSE_MAPPING 552 ef->object = vm_object_allocate(OBJT_DEFAULT, mapsize >> PAGE_SHIFT); 553 if (ef->object == NULL) { 554 free(ef, M_LINKER); 555 error = ENOMEM; 556 goto out; 557 } 558 vm_object_reference(ef->object); 559 ef->address = (caddr_t) vm_map_min(kernel_map); 560 error = vm_map_find(kernel_map, ef->object, 0, 561 (vm_offset_t *) &ef->address, 562 mapsize, 1, 563 VM_PROT_ALL, VM_PROT_ALL, 0); 564 if (error) { 565 vm_object_deallocate(ef->object); 566 free(ef, M_LINKER); 567 goto out; 568 } 569 #else 570 ef->address = malloc(mapsize, M_LINKER, M_WAITOK); 571 #endif 572 mapbase = ef->address; 573 574 /* 575 * Read the text and data sections and zero the bss. 576 */ 577 for (i = 0; i < 2; i++) { 578 caddr_t segbase = mapbase + segs[i]->p_vaddr - base_vaddr; 579 error = vn_rdwr(UIO_READ, nd.ni_vp, 580 segbase, segs[i]->p_filesz, segs[i]->p_offset, 581 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, td); 582 if (error) { 583 #ifdef SPARSE_MAPPING 584 vm_map_remove(kernel_map, (vm_offset_t) ef->address, 585 (vm_offset_t) ef->address 586 + (ef->object->size << PAGE_SHIFT)); 587 vm_object_deallocate(ef->object); 588 #else 589 free(ef->address, M_LINKER); 590 #endif 591 free(ef, M_LINKER); 592 goto out; 593 } 594 bzero(segbase + segs[i]->p_filesz, 595 segs[i]->p_memsz - segs[i]->p_filesz); 596 597 #ifdef SPARSE_MAPPING 598 /* 599 * Wire down the pages 600 */ 601 vm_map_wire(kernel_map, 602 (vm_offset_t) segbase, 603 (vm_offset_t) segbase + segs[i]->p_memsz, 604 FALSE); 605 #endif 606 } 607 608 ef->dynamic = (const Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr); 609 610 lf = linker_make_file(filename, ef, &link_elf_file_ops); 611 if (lf == NULL) { 612 #ifdef SPARSE_MAPPING 613 vm_map_remove(kernel_map, (vm_offset_t) ef->address, 614 (vm_offset_t) ef->address 615 + (ef->object->size << PAGE_SHIFT)); 616 vm_object_deallocate(ef->object); 617 #else 618 free(ef->address, M_LINKER); 619 #endif 620 free(ef, M_LINKER); 621 error = ENOMEM; 622 goto out; 623 } 624 lf->address = ef->address; 625 lf->size = mapsize; 626 627 error = parse_dynamic(lf); 628 if (error) 629 goto out; 630 error = load_dependancies(lf); 631 if (error) 632 goto out; 633 error = relocate_file(lf); 634 if (error) 635 goto out; 636 637 /* Try and load the symbol table if it's present. (you can strip it!) */ 638 nbytes = hdr->e_shnum * hdr->e_shentsize; 639 if (nbytes == 0 || hdr->e_shoff == 0) 640 goto nosyms; 641 shdr = malloc(nbytes, M_LINKER, M_WAITOK); 642 if (shdr == NULL) { 643 error = ENOMEM; 644 goto out; 645 } 646 bzero(shdr, nbytes); 647 error = vn_rdwr(UIO_READ, nd.ni_vp, 648 (caddr_t)shdr, nbytes, hdr->e_shoff, 649 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, td); 650 if (error) 651 goto out; 652 symtabindex = -1; 653 symstrindex = -1; 654 for (i = 0; i < hdr->e_shnum; i++) { 655 if (shdr[i].sh_type == SHT_SYMTAB) { 656 symtabindex = i; 657 symstrindex = shdr[i].sh_link; 658 } 659 } 660 if (symtabindex < 0 || symstrindex < 0) 661 goto nosyms; 662 663 symcnt = shdr[symtabindex].sh_size; 664 ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK); 665 strcnt = shdr[symstrindex].sh_size; 666 ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK); 667 668 if (ef->symbase == NULL || ef->strbase == NULL) { 669 error = ENOMEM; 670 goto out; 671 } 672 error = vn_rdwr(UIO_READ, nd.ni_vp, 673 ef->symbase, symcnt, shdr[symtabindex].sh_offset, 674 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, td); 675 if (error) 676 goto out; 677 error = vn_rdwr(UIO_READ, nd.ni_vp, 678 ef->strbase, strcnt, shdr[symstrindex].sh_offset, 679 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, td); 680 if (error) 681 goto out; 682 683 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym); 684 ef->ddbsymtab = (const Elf_Sym *)ef->symbase; 685 ef->ddbstrcnt = strcnt; 686 ef->ddbstrtab = ef->strbase; 687 688 lf->flags |= LINKER_FILE_LINKED; 689 690 nosyms: 691 692 *result = lf; 693 694 out: 695 if (error && lf) 696 linker_file_unload(lf); 697 if (shdr) 698 free(shdr, M_LINKER); 699 if (firstpage) 700 free(firstpage, M_LINKER); 701 VOP_UNLOCK(nd.ni_vp, 0, td); 702 vn_close(nd.ni_vp, FREAD, td); 703 704 return error; 705 } 706 707 static void 708 link_elf_unload_file(linker_file_t file) 709 { 710 elf_file_t ef = file->priv; 711 712 if (ef) { 713 #ifdef SPARSE_MAPPING 714 if (ef->object) { 715 vm_map_remove(kernel_map, (vm_offset_t) ef->address, 716 (vm_offset_t) ef->address 717 + (ef->object->size << PAGE_SHIFT)); 718 vm_object_deallocate(ef->object); 719 } 720 #else 721 if (ef->address) 722 free(ef->address, M_LINKER); 723 #endif 724 if (ef->symbase) 725 free(ef->symbase, M_LINKER); 726 if (ef->strbase) 727 free(ef->strbase, M_LINKER); 728 free(ef, M_LINKER); 729 } 730 } 731 732 static void 733 link_elf_unload_module(linker_file_t file) 734 { 735 elf_file_t ef = file->priv; 736 737 if (ef) 738 free(ef, M_LINKER); 739 if (file->filename) 740 preload_delete_name(file->filename); 741 } 742 743 static int 744 load_dependancies(linker_file_t lf) 745 { 746 elf_file_t ef = lf->priv; 747 linker_file_t lfdep; 748 char* name; 749 const Elf_Dyn *dp; 750 int error = 0; 751 752 /* 753 * All files are dependant on /kernel. 754 */ 755 if (linker_kernel_file) { 756 linker_kernel_file->refs++; 757 linker_file_add_dependancy(lf, linker_kernel_file); 758 } 759 760 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) { 761 if (dp->d_tag == DT_NEEDED) { 762 name = ef->strtab + dp->d_un.d_val; 763 764 error = linker_load_file(name, &lfdep); 765 if (error) 766 goto out; 767 error = linker_file_add_dependancy(lf, lfdep); 768 if (error) 769 goto out; 770 } 771 } 772 773 out: 774 return error; 775 } 776 777 static const char * 778 symbol_name(elf_file_t ef, Elf_Word r_info) 779 { 780 const Elf_Sym *ref; 781 782 if (ELF_R_SYM(r_info)) { 783 ref = ef->symtab + ELF_R_SYM(r_info); 784 return ef->strtab + ref->st_name; 785 } else 786 return NULL; 787 } 788 789 static int 790 relocate_file(linker_file_t lf) 791 { 792 elf_file_t ef = lf->priv; 793 const Elf_Rel *rellim; 794 const Elf_Rel *rel; 795 const Elf_Rela *relalim; 796 const Elf_Rela *rela; 797 const char *symname; 798 799 /* Perform relocations without addend if there are any: */ 800 rel = ef->rel; 801 if (rel) { 802 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize); 803 while (rel < rellim) { 804 symname = symbol_name(ef, rel->r_info); 805 if (elf_reloc(lf, rel, ELF_RELOC_REL, symname)) { 806 printf("link_elf: symbol %s undefined\n", symname); 807 return ENOENT; 808 } 809 rel++; 810 } 811 } 812 813 /* Perform relocations with addend if there are any: */ 814 rela = ef->rela; 815 if (rela) { 816 relalim = (const Elf_Rela *)((const char *)ef->rela + ef->relasize); 817 while (rela < relalim) { 818 symname = symbol_name(ef, rela->r_info); 819 if (elf_reloc(lf, rela, ELF_RELOC_RELA, symname)) { 820 printf("link_elf: symbol %s undefined\n", symname); 821 return ENOENT; 822 } 823 rela++; 824 } 825 } 826 827 /* Perform PLT relocations without addend if there are any: */ 828 rel = ef->pltrel; 829 if (rel) { 830 rellim = (const Elf_Rel *)((const char *)ef->pltrel + ef->pltrelsize); 831 while (rel < rellim) { 832 symname = symbol_name(ef, rel->r_info); 833 if (elf_reloc(lf, rel, ELF_RELOC_REL, symname)) { 834 printf("link_elf: symbol %s undefined\n", symname); 835 return ENOENT; 836 } 837 rel++; 838 } 839 } 840 841 /* Perform relocations with addend if there are any: */ 842 rela = ef->pltrela; 843 if (rela) { 844 relalim = (const Elf_Rela *)((const char *)ef->pltrela + ef->pltrelasize); 845 while (rela < relalim) { 846 symname = symbol_name(ef, rela->r_info); 847 if (elf_reloc(lf, rela, ELF_RELOC_RELA, symname)) { 848 printf("link_elf: symbol %s undefined\n", symname); 849 return ENOENT; 850 } 851 rela++; 852 } 853 } 854 855 return 0; 856 } 857 858 /* 859 * Hash function for symbol table lookup. Don't even think about changing 860 * this. It is specified by the System V ABI. 861 */ 862 static unsigned long 863 elf_hash(const char *name) 864 { 865 const unsigned char *p = (const unsigned char *) name; 866 unsigned long h = 0; 867 unsigned long g; 868 869 while (*p != '\0') { 870 h = (h << 4) + *p++; 871 if ((g = h & 0xf0000000) != 0) 872 h ^= g >> 24; 873 h &= ~g; 874 } 875 return h; 876 } 877 878 int 879 link_elf_lookup_symbol(linker_file_t lf, const char* name, c_linker_sym_t* sym) 880 { 881 elf_file_t ef = lf->priv; 882 unsigned long symnum; 883 const Elf_Sym* symp; 884 const char *strp; 885 unsigned long hash; 886 int i; 887 888 /* First, search hashed global symbols */ 889 hash = elf_hash(name); 890 symnum = ef->buckets[hash % ef->nbuckets]; 891 892 while (symnum != STN_UNDEF) { 893 if (symnum >= ef->nchains) { 894 printf("link_elf_lookup_symbol: corrupt symbol table\n"); 895 return ENOENT; 896 } 897 898 symp = ef->symtab + symnum; 899 if (symp->st_name == 0) { 900 printf("link_elf_lookup_symbol: corrupt symbol table\n"); 901 return ENOENT; 902 } 903 904 strp = ef->strtab + symp->st_name; 905 906 if (strcmp(name, strp) == 0) { 907 if (symp->st_shndx != SHN_UNDEF || 908 (symp->st_value != 0 && 909 ELF_ST_TYPE(symp->st_info) == STT_FUNC) 910 ) { 911 *sym = (c_linker_sym_t) symp; 912 return 0; 913 } else { 914 return ENOENT; 915 } 916 } 917 918 symnum = ef->chains[symnum]; 919 } 920 921 /* If we have not found it, look at the full table (if loaded) */ 922 if (ef->symtab == ef->ddbsymtab) 923 return ENOENT; 924 925 /* Exhaustive search */ 926 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 927 strp = ef->ddbstrtab + symp->st_name; 928 if (strcmp(name, strp) == 0) { 929 if (symp->st_shndx != SHN_UNDEF || 930 (symp->st_value != 0 && 931 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) { 932 *sym = (c_linker_sym_t) symp; 933 return 0; 934 } else { 935 return ENOENT; 936 } 937 } 938 } 939 return ENOENT; 940 } 941 942 static int 943 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, linker_symval_t* symval) 944 { 945 elf_file_t ef = lf->priv; 946 const Elf_Sym* es = (const Elf_Sym*) sym; 947 948 if (es >= ef->symtab && ((es - ef->symtab) < ef->nchains)) { 949 symval->name = ef->strtab + es->st_name; 950 symval->value = (caddr_t) ef->address + es->st_value; 951 symval->size = es->st_size; 952 return 0; 953 } 954 if (ef->symtab == ef->ddbsymtab) 955 return ENOENT; 956 if (es >= ef->ddbsymtab && ((es - ef->ddbsymtab) < ef->ddbsymcnt)) { 957 symval->name = ef->ddbstrtab + es->st_name; 958 symval->value = (caddr_t) ef->address + es->st_value; 959 symval->size = es->st_size; 960 return 0; 961 } 962 return ENOENT; 963 } 964 965 static int 966 link_elf_search_symbol(linker_file_t lf, caddr_t value, 967 c_linker_sym_t* sym, long* diffp) 968 { 969 elf_file_t ef = lf->priv; 970 u_long off = (uintptr_t) (void *) value; 971 u_long diff = off; 972 u_long st_value; 973 const Elf_Sym* es; 974 const Elf_Sym* best = 0; 975 int i; 976 977 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) { 978 if (es->st_name == 0) 979 continue; 980 st_value = es->st_value + (uintptr_t) (void *) ef->address; 981 if (off >= st_value) { 982 if (off - st_value < diff) { 983 diff = off - st_value; 984 best = es; 985 if (diff == 0) 986 break; 987 } else if (off - st_value == diff) { 988 best = es; 989 } 990 } 991 } 992 if (best == 0) 993 *diffp = off; 994 else 995 *diffp = diff; 996 *sym = (c_linker_sym_t) best; 997 998 return 0; 999 } 1000 1001 /* 1002 * Look up a linker set on an ELF system. 1003 */ 1004 static int 1005 link_elf_lookup_set(linker_file_t lf, const char *name, 1006 void ***startp, void ***stopp, int *countp) 1007 { 1008 c_linker_sym_t sym; 1009 linker_symval_t symval; 1010 char *setsym; 1011 void **start, **stop; 1012 int len, error = 0, count; 1013 1014 len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */ 1015 setsym = malloc(len, M_LINKER, M_WAITOK); 1016 if (setsym == NULL) 1017 return ENOMEM; 1018 1019 /* get address of first entry */ 1020 snprintf(setsym, len, "%s%s", "__start_set_", name); 1021 error = link_elf_lookup_symbol(lf, setsym, &sym); 1022 if (error) 1023 goto out; 1024 link_elf_symbol_values(lf, sym, &symval); 1025 if (symval.value == 0) { 1026 error = ESRCH; 1027 goto out; 1028 } 1029 start = (void **)symval.value; 1030 1031 /* get address of last entry */ 1032 snprintf(setsym, len, "%s%s", "__stop_set_", name); 1033 error = link_elf_lookup_symbol(lf, setsym, &sym); 1034 if (error) 1035 goto out; 1036 link_elf_symbol_values(lf, sym, &symval); 1037 if (symval.value == 0) { 1038 error = ESRCH; 1039 goto out; 1040 } 1041 stop = (void **)symval.value; 1042 1043 /* and the number of entries */ 1044 count = stop - start; 1045 1046 /* and copy out */ 1047 if (startp) 1048 *startp = start; 1049 if (stopp) 1050 *stopp = stop; 1051 if (countp) 1052 *countp = count; 1053 1054 out: 1055 free(setsym, M_LINKER); 1056 return error; 1057 } 1058 1059