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 * $Id: link_elf.c,v 1.10 1998/11/06 15:16:07 peter Exp $ 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 linker_sym_t*); 54 static int link_elf_symbol_values(linker_file_t, linker_sym_t, linker_symval_t*); 55 static int link_elf_search_symbol(linker_file_t, caddr_t value, 56 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 /* Sigh, magic constants. */ 160 #ifdef __alpha__ 161 linker_kernel_file->address = (caddr_t) 0xfffffc0000300000; 162 #else 163 linker_kernel_file->address = (caddr_t) 0xf0100000; 164 #endif 165 linker_kernel_file->size = -(long)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 } 179 #endif 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 /* Look to see if we have the module preloaded */ 338 modptr = preload_search_by_name(filename); 339 if (modptr == NULL) 340 return (link_elf_load_file(filename, result)); 341 342 /* It's preloaded, check we can handle it and collect information */ 343 type = (char *)preload_search_info(modptr, MODINFO_TYPE); 344 baseptr = preload_search_info(modptr, MODINFO_ADDR); 345 sizeptr = preload_search_info(modptr, MODINFO_SIZE); 346 dynptr = preload_search_info(modptr, MODINFO_METADATA|MODINFOMD_DYNAMIC); 347 if (type == NULL || strcmp(type, "elf module") != 0) 348 return (EFTYPE); 349 if (baseptr == NULL || sizeptr == NULL || dynptr == NULL) 350 return (EINVAL); 351 352 ef = malloc(sizeof(struct elf_file), M_LINKER, M_WAITOK); 353 if (ef == NULL) 354 return (ENOMEM); 355 bzero(ef, sizeof(*ef)); 356 ef->modptr = modptr; 357 ef->address = *(caddr_t *)baseptr; 358 #ifdef SPARSE_MAPPING 359 ef->object = 0; 360 #endif 361 dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr; 362 ef->dynamic = (Elf_Dyn *)dp; 363 lf = linker_make_file(filename, ef, &link_elf_module_ops); 364 if (lf == NULL) { 365 free(ef, M_LINKER); 366 return ENOMEM; 367 } 368 lf->address = ef->address; 369 lf->size = *(size_t *)sizeptr; 370 371 error = parse_dynamic(lf); 372 if (error) { 373 linker_file_unload(lf); 374 return error; 375 } 376 error = load_dependancies(lf); 377 if (error) { 378 linker_file_unload(lf); 379 return error; 380 } 381 error = relocate_file(lf); 382 if (error) { 383 linker_file_unload(lf); 384 return error; 385 } 386 (void)parse_module_symbols(lf); 387 *result = lf; 388 return (0); 389 } 390 391 static int 392 link_elf_load_file(const char* filename, linker_file_t* result) 393 { 394 struct nameidata nd; 395 struct proc* p = curproc; /* XXX */ 396 Elf_Ehdr *hdr; 397 caddr_t firstpage; 398 int nbytes, i; 399 Elf_Phdr *phdr; 400 Elf_Phdr *phlimit; 401 Elf_Phdr *segs[2]; 402 int nsegs; 403 Elf_Phdr *phdyn; 404 Elf_Phdr *phphdr; 405 caddr_t mapbase; 406 size_t mapsize; 407 Elf_Off base_offset; 408 Elf_Addr base_vaddr; 409 Elf_Addr base_vlimit; 410 int error = 0; 411 int resid; 412 elf_file_t ef; 413 linker_file_t lf; 414 char *pathname; 415 Elf_Shdr *shdr; 416 int symtabindex; 417 int symstrindex; 418 int symcnt; 419 int strcnt; 420 421 shdr = NULL; 422 lf = NULL; 423 424 pathname = linker_search_path(filename); 425 if (pathname == NULL) 426 return ENOENT; 427 428 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, pathname, p); 429 error = vn_open(&nd, FREAD, 0); 430 free(pathname, M_LINKER); 431 if (error) 432 return error; 433 434 /* 435 * Read the elf header from the file. 436 */ 437 firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK); 438 if (firstpage == NULL) { 439 error = ENOMEM; 440 goto out; 441 } 442 hdr = (Elf_Ehdr *)firstpage; 443 error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0, 444 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, p); 445 nbytes = PAGE_SIZE - resid; 446 if (error) 447 goto out; 448 449 if (!IS_ELF(*hdr)) { 450 error = ENOEXEC; 451 goto out; 452 } 453 454 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS 455 || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) { 456 link_elf_error("Unsupported file layout"); 457 error = ENOEXEC; 458 goto out; 459 } 460 if (hdr->e_ident[EI_VERSION] != EV_CURRENT 461 || hdr->e_version != EV_CURRENT) { 462 link_elf_error("Unsupported file version"); 463 error = ENOEXEC; 464 goto out; 465 } 466 if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) { 467 link_elf_error("Unsupported file type"); 468 error = ENOEXEC; 469 goto out; 470 } 471 if (hdr->e_machine != ELF_TARG_MACH) { 472 link_elf_error("Unsupported machine"); 473 error = ENOEXEC; 474 goto out; 475 } 476 477 /* 478 * We rely on the program header being in the first page. This is 479 * not strictly required by the ABI specification, but it seems to 480 * always true in practice. And, it simplifies things considerably. 481 */ 482 if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) && 483 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) && 484 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes))) 485 link_elf_error("Unreadable program headers"); 486 487 /* 488 * Scan the program header entries, and save key information. 489 * 490 * We rely on there being exactly two load segments, text and data, 491 * in that order. 492 */ 493 phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff); 494 phlimit = phdr + hdr->e_phnum; 495 nsegs = 0; 496 phdyn = NULL; 497 phphdr = NULL; 498 while (phdr < phlimit) { 499 switch (phdr->p_type) { 500 501 case PT_LOAD: 502 if (nsegs == 2) { 503 link_elf_error("Too many sections"); 504 error = ENOEXEC; 505 goto out; 506 } 507 segs[nsegs] = phdr; 508 ++nsegs; 509 break; 510 511 case PT_PHDR: 512 phphdr = phdr; 513 break; 514 515 case PT_DYNAMIC: 516 phdyn = phdr; 517 break; 518 } 519 520 ++phdr; 521 } 522 if (phdyn == NULL) { 523 link_elf_error("Object is not dynamically-linked"); 524 error = ENOEXEC; 525 goto out; 526 } 527 528 /* 529 * Allocate the entire address space of the object, to stake out our 530 * contiguous region, and to establish the base address for relocation. 531 */ 532 base_offset = trunc_page(segs[0]->p_offset); 533 base_vaddr = trunc_page(segs[0]->p_vaddr); 534 base_vlimit = round_page(segs[1]->p_vaddr + segs[1]->p_memsz); 535 mapsize = base_vlimit - base_vaddr; 536 537 ef = malloc(sizeof(struct elf_file), M_LINKER, M_WAITOK); 538 bzero(ef, sizeof(*ef)); 539 #ifdef SPARSE_MAPPING 540 ef->object = vm_object_allocate(OBJT_DEFAULT, mapsize >> PAGE_SHIFT); 541 if (ef->object == NULL) { 542 free(ef, M_LINKER); 543 error = ENOMEM; 544 goto out; 545 } 546 vm_object_reference(ef->object); 547 ef->address = (caddr_t) vm_map_min(kernel_map); 548 error = vm_map_find(kernel_map, ef->object, 0, 549 (vm_offset_t *) &ef->address, 550 mapsize, 1, 551 VM_PROT_ALL, VM_PROT_ALL, 0); 552 if (error) { 553 vm_object_deallocate(ef->object); 554 free(ef, M_LINKER); 555 goto out; 556 } 557 #else 558 ef->address = malloc(mapsize, M_LINKER, M_WAITOK); 559 #endif 560 mapbase = ef->address; 561 562 /* 563 * Read the text and data sections and zero the bss. 564 */ 565 for (i = 0; i < 2; i++) { 566 caddr_t segbase = mapbase + segs[i]->p_vaddr - base_vaddr; 567 error = vn_rdwr(UIO_READ, nd.ni_vp, 568 segbase, segs[i]->p_filesz, segs[i]->p_offset, 569 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, p); 570 if (error) { 571 #ifdef SPARSE_MAPPING 572 vm_map_remove(kernel_map, (vm_offset_t) ef->address, 573 (vm_offset_t) ef->address 574 + (ef->object->size << PAGE_SHIFT)); 575 vm_object_deallocate(ef->object); 576 #else 577 free(ef->address, M_LINKER); 578 #endif 579 free(ef, M_LINKER); 580 goto out; 581 } 582 bzero(segbase + segs[i]->p_filesz, 583 segs[i]->p_memsz - segs[i]->p_filesz); 584 585 #ifdef SPARSE_MAPPING 586 /* 587 * Wire down the pages 588 */ 589 vm_map_pageable(kernel_map, 590 (vm_offset_t) segbase, 591 (vm_offset_t) segbase + segs[i]->p_memsz, 592 FALSE); 593 #endif 594 } 595 596 ef->dynamic = (const Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr); 597 598 lf = linker_make_file(filename, ef, &link_elf_file_ops); 599 if (lf == NULL) { 600 #ifdef SPARSE_MAPPING 601 vm_map_remove(kernel_map, (vm_offset_t) ef->address, 602 (vm_offset_t) ef->address 603 + (ef->object->size << PAGE_SHIFT)); 604 vm_object_deallocate(ef->object); 605 #else 606 free(ef->address, M_LINKER); 607 #endif 608 free(ef, M_LINKER); 609 error = ENOMEM; 610 goto out; 611 } 612 lf->address = ef->address; 613 lf->size = mapsize; 614 615 error = parse_dynamic(lf); 616 if (error) 617 goto out; 618 error = load_dependancies(lf); 619 if (error) 620 goto out; 621 error = relocate_file(lf); 622 if (error) 623 goto out; 624 625 /* Try and load the symbol table if it's present. (you can strip it!) */ 626 nbytes = hdr->e_shnum * hdr->e_shentsize; 627 if (nbytes == 0 || hdr->e_shoff == 0) 628 goto nosyms; 629 shdr = malloc(nbytes, M_LINKER, M_WAITOK); 630 if (shdr == NULL) { 631 error = ENOMEM; 632 goto out; 633 } 634 bzero(shdr, nbytes); 635 error = vn_rdwr(UIO_READ, nd.ni_vp, 636 (caddr_t)shdr, nbytes, hdr->e_shoff, 637 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, p); 638 if (error) 639 goto out; 640 symtabindex = -1; 641 symstrindex = -1; 642 for (i = 0; i < hdr->e_shnum; i++) { 643 if (shdr[i].sh_type == SHT_SYMTAB) { 644 symtabindex = i; 645 symstrindex = shdr[i].sh_link; 646 } 647 } 648 if (symtabindex < 0 || symstrindex < 0) 649 goto nosyms; 650 651 symcnt = shdr[symtabindex].sh_size; 652 ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK); 653 strcnt = shdr[symstrindex].sh_size; 654 ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK); 655 656 if (ef->symbase == NULL || ef->strbase == NULL) { 657 error = ENOMEM; 658 goto out; 659 } 660 error = vn_rdwr(UIO_READ, nd.ni_vp, 661 ef->symbase, symcnt, shdr[symtabindex].sh_offset, 662 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, p); 663 if (error) 664 goto out; 665 error = vn_rdwr(UIO_READ, nd.ni_vp, 666 ef->strbase, strcnt, shdr[symstrindex].sh_offset, 667 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, p); 668 if (error) 669 goto out; 670 671 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym); 672 ef->ddbsymtab = (const Elf_Sym *)ef->symbase; 673 ef->ddbstrcnt = strcnt; 674 ef->ddbstrtab = ef->strbase; 675 676 nosyms: 677 678 *result = lf; 679 680 out: 681 if (error && lf) 682 linker_file_unload(lf); 683 if (shdr) 684 free(shdr, M_LINKER); 685 if (firstpage) 686 free(firstpage, M_LINKER); 687 VOP_UNLOCK(nd.ni_vp, 0, p); 688 vn_close(nd.ni_vp, FREAD, p->p_ucred, p); 689 690 return error; 691 } 692 693 static void 694 link_elf_unload_file(linker_file_t file) 695 { 696 elf_file_t ef = file->priv; 697 698 if (ef) { 699 #ifdef SPARSE_MAPPING 700 if (ef->object) { 701 vm_map_remove(kernel_map, (vm_offset_t) ef->address, 702 (vm_offset_t) ef->address 703 + (ef->object->size << PAGE_SHIFT)); 704 vm_object_deallocate(ef->object); 705 } 706 #else 707 if (ef->address) 708 free(ef->address, M_LINKER); 709 #endif 710 if (ef->symbase) 711 free(ef->symbase, M_LINKER); 712 if (ef->strbase) 713 free(ef->strbase, M_LINKER); 714 free(ef, M_LINKER); 715 } 716 } 717 718 static void 719 link_elf_unload_module(linker_file_t file) 720 { 721 elf_file_t ef = file->priv; 722 723 if (ef) 724 free(ef, M_LINKER); 725 if (file->filename) 726 preload_delete_name(file->filename); 727 } 728 729 static int 730 load_dependancies(linker_file_t lf) 731 { 732 elf_file_t ef = lf->priv; 733 linker_file_t lfdep; 734 char* name; 735 const Elf_Dyn *dp; 736 int error = 0; 737 738 /* 739 * All files are dependant on /kernel. 740 */ 741 if (linker_kernel_file) { 742 linker_kernel_file->refs++; 743 linker_file_add_dependancy(lf, linker_kernel_file); 744 } 745 746 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) { 747 if (dp->d_tag == DT_NEEDED) { 748 name = ef->strtab + dp->d_un.d_val; 749 750 error = linker_load_file(name, &lfdep); 751 if (error) 752 goto out; 753 error = linker_file_add_dependancy(lf, lfdep); 754 if (error) 755 goto out; 756 } 757 } 758 759 out: 760 return error; 761 } 762 763 static const char * 764 symbol_name(elf_file_t ef, Elf_Word r_info) 765 { 766 const Elf_Sym *ref; 767 768 if (ELF_R_SYM(r_info)) { 769 ref = ef->symtab + ELF_R_SYM(r_info); 770 return ef->strtab + ref->st_name; 771 } else 772 return NULL; 773 } 774 775 static int 776 relocate_file(linker_file_t lf) 777 { 778 elf_file_t ef = lf->priv; 779 const Elf_Rel *rellim; 780 const Elf_Rel *rel; 781 const Elf_Rela *relalim; 782 const Elf_Rela *rela; 783 const char *symname; 784 785 /* Perform relocations without addend if there are any: */ 786 rel = ef->rel; 787 if (rel) { 788 rellim = (const Elf_Rel *) ((caddr_t) ef->rel + ef->relsize); 789 while (rel < rellim) { 790 symname = symbol_name(ef, rel->r_info); 791 if (elf_reloc(lf, rel, ELF_RELOC_REL, symname)) { 792 printf("link_elf: symbol %s undefined\n", symname); 793 return ENOENT; 794 } 795 rel++; 796 } 797 } 798 799 /* Perform relocations with addend if there are any: */ 800 rela = ef->rela; 801 if (rela) { 802 relalim = (const Elf_Rela *) ((caddr_t) ef->rela + ef->relasize); 803 while (rela < relalim) { 804 symname = symbol_name(ef, rela->r_info); 805 if (elf_reloc(lf, rela, ELF_RELOC_RELA, symname)) { 806 printf("link_elf: symbol %s undefined\n", symname); 807 return ENOENT; 808 } 809 rela++; 810 } 811 } 812 813 /* Perform PLT relocations without addend if there are any: */ 814 rel = ef->pltrel; 815 if (rel) { 816 rellim = (const Elf_Rel *) ((caddr_t) ef->pltrel + ef->pltrelsize); 817 while (rel < rellim) { 818 symname = symbol_name(ef, rel->r_info); 819 if (elf_reloc(lf, rel, ELF_RELOC_REL, symname)) { 820 printf("link_elf: symbol %s undefined\n", symname); 821 return ENOENT; 822 } 823 rel++; 824 } 825 } 826 827 /* Perform relocations with addend if there are any: */ 828 rela = ef->pltrela; 829 if (rela) { 830 relalim = (const Elf_Rela *) ((caddr_t) ef->pltrela + ef->pltrelasize); 831 while (rela < relalim) { 832 symname = symbol_name(ef, rela->r_info); 833 if (elf_reloc(lf, rela, ELF_RELOC_RELA, symname)) { 834 printf("link_elf: symbol %s undefined\n", symname); 835 return ENOENT; 836 } 837 rela++; 838 } 839 } 840 841 return 0; 842 } 843 844 /* 845 * Hash function for symbol table lookup. Don't even think about changing 846 * this. It is specified by the System V ABI. 847 */ 848 static unsigned long 849 elf_hash(const char *name) 850 { 851 const unsigned char *p = (const unsigned char *) name; 852 unsigned long h = 0; 853 unsigned long g; 854 855 while (*p != '\0') { 856 h = (h << 4) + *p++; 857 if ((g = h & 0xf0000000) != 0) 858 h ^= g >> 24; 859 h &= ~g; 860 } 861 return h; 862 } 863 864 int 865 link_elf_lookup_symbol(linker_file_t lf, const char* name, linker_sym_t* sym) 866 { 867 elf_file_t ef = lf->priv; 868 unsigned long symnum; 869 const Elf_Sym* symp; 870 const char *strp; 871 unsigned long hash; 872 int i; 873 874 /* First, search hashed global symbols */ 875 hash = elf_hash(name); 876 symnum = ef->buckets[hash % ef->nbuckets]; 877 878 while (symnum != STN_UNDEF) { 879 if (symnum >= ef->nchains) { 880 printf("link_elf_lookup_symbol: corrupt symbol table\n"); 881 return ENOENT; 882 } 883 884 symp = ef->symtab + symnum; 885 if (symp->st_name == 0) { 886 printf("link_elf_lookup_symbol: corrupt symbol table\n"); 887 return ENOENT; 888 } 889 890 strp = ef->strtab + symp->st_name; 891 892 if (strcmp(name, strp) == 0) { 893 if (symp->st_shndx != SHN_UNDEF || 894 (symp->st_value != 0 && 895 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) { 896 *sym = (linker_sym_t) symp; 897 return 0; 898 } else 899 return ENOENT; 900 } 901 902 symnum = ef->chains[symnum]; 903 } 904 905 /* If we have not found it, look at the full table (if loaded) */ 906 if (ef->symtab == ef->ddbsymtab) 907 return ENOENT; 908 909 /* Exhaustive search */ 910 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 911 strp = ef->ddbstrtab + symp->st_name; 912 if (strcmp(name, strp) == 0) { 913 if (symp->st_shndx != SHN_UNDEF || 914 (symp->st_value != 0 && 915 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) { 916 *sym = (linker_sym_t) symp; 917 return 0; 918 } else 919 return ENOENT; 920 } 921 } 922 923 return ENOENT; 924 } 925 926 static int 927 link_elf_symbol_values(linker_file_t lf, linker_sym_t sym, linker_symval_t* symval) 928 { 929 elf_file_t ef = lf->priv; 930 Elf_Sym* es = (Elf_Sym*) sym; 931 932 if (es >= ef->symtab && ((es - ef->symtab) < ef->nchains)) { 933 symval->name = ef->strtab + es->st_name; 934 symval->value = (caddr_t) ef->address + es->st_value; 935 symval->size = es->st_size; 936 return 0; 937 } 938 if (ef->symtab == ef->ddbsymtab) 939 return ENOENT; 940 if (es >= ef->ddbsymtab && ((es - ef->ddbsymtab) < ef->ddbsymcnt)) { 941 symval->name = ef->ddbstrtab + es->st_name; 942 symval->value = (caddr_t) ef->address + es->st_value; 943 symval->size = es->st_size; 944 return 0; 945 } 946 return ENOENT; 947 } 948 949 static int 950 link_elf_search_symbol(linker_file_t lf, caddr_t value, 951 linker_sym_t* sym, long* diffp) 952 { 953 elf_file_t ef = lf->priv; 954 u_long off = (u_long) value; 955 u_long diff = off; 956 const Elf_Sym* es; 957 const Elf_Sym* best = 0; 958 int i; 959 960 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) { 961 if (es->st_name == 0) 962 continue; 963 if (off >= es->st_value) { 964 if (off - es->st_value < diff) { 965 diff = off - es->st_value; 966 best = es; 967 if (diff == 0) 968 break; 969 } else if (off - es->st_value == diff) { 970 best = es; 971 } 972 } 973 } 974 if (best == 0) 975 *diffp = off; 976 else 977 *diffp = diff; 978 *sym = (linker_sym_t) best; 979 980 return 0; 981 } 982