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