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 1.5 2003/07/18 05:12:39 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 64 static struct linker_class_ops link_elf_class_ops = { 65 link_elf_load_module, 66 }; 67 68 static struct linker_file_ops link_elf_file_ops = { 69 link_elf_lookup_symbol, 70 link_elf_symbol_values, 71 link_elf_search_symbol, 72 link_elf_unload_file, 73 }; 74 75 static struct linker_file_ops link_elf_module_ops = { 76 link_elf_lookup_symbol, 77 link_elf_symbol_values, 78 link_elf_search_symbol, 79 link_elf_unload_module, 80 }; 81 typedef struct elf_file { 82 caddr_t address; /* Relocation address */ 83 #ifdef SPARSE_MAPPING 84 vm_object_t object; /* VM object to hold file pages */ 85 #endif 86 const Elf_Dyn* dynamic; /* Symbol table etc. */ 87 Elf_Off nbuckets; /* DT_HASH info */ 88 Elf_Off nchains; 89 const Elf_Off* buckets; 90 const Elf_Off* chains; 91 caddr_t hash; 92 caddr_t strtab; /* DT_STRTAB */ 93 int strsz; /* DT_STRSZ */ 94 const Elf_Sym* symtab; /* DT_SYMTAB */ 95 Elf_Addr* got; /* DT_PLTGOT */ 96 const Elf_Rel* pltrel; /* DT_JMPREL */ 97 int pltrelsize; /* DT_PLTRELSZ */ 98 const Elf_Rela* pltrela; /* DT_JMPREL */ 99 int pltrelasize; /* DT_PLTRELSZ */ 100 const Elf_Rel* rel; /* DT_REL */ 101 int relsize; /* DT_RELSZ */ 102 const Elf_Rela* rela; /* DT_RELA */ 103 int relasize; /* DT_RELASZ */ 104 caddr_t modptr; 105 const Elf_Sym* ddbsymtab; /* The symbol table we are using */ 106 long ddbsymcnt; /* Number of symbols */ 107 caddr_t ddbstrtab; /* String table */ 108 long ddbstrcnt; /* number of bytes in string table */ 109 caddr_t symbase; /* malloc'ed symbold base */ 110 caddr_t strbase; /* malloc'ed string base */ 111 } *elf_file_t; 112 113 static int parse_dynamic(linker_file_t lf); 114 static int load_dependancies(linker_file_t lf); 115 static int relocate_file(linker_file_t lf); 116 static int parse_module_symbols(linker_file_t lf); 117 118 /* 119 * The kernel symbol table starts here. 120 */ 121 extern struct _dynamic _DYNAMIC; 122 123 static void 124 link_elf_init(void* arg) 125 { 126 #ifdef __ELF__ 127 Elf_Dyn *dp; 128 caddr_t modptr, baseptr, sizeptr; 129 elf_file_t ef; 130 char *modname; 131 #endif 132 133 #if ELF_TARG_CLASS == ELFCLASS32 134 linker_add_class("elf32", NULL, &link_elf_class_ops); 135 #else 136 linker_add_class("elf64", NULL, &link_elf_class_ops); 137 #endif 138 139 #ifdef __ELF__ 140 dp = (Elf_Dyn*) &_DYNAMIC; 141 if (dp) { 142 ef = malloc(sizeof(struct elf_file), M_LINKER, M_NOWAIT); 143 if (ef == NULL) 144 panic("link_elf_init: Can't create linker structures for kernel"); 145 bzero(ef, sizeof(*ef)); 146 147 ef->address = 0; 148 #ifdef SPARSE_MAPPING 149 ef->object = 0; 150 #endif 151 ef->dynamic = dp; 152 modname = NULL; 153 modptr = preload_search_by_type("elf kernel"); 154 if (modptr) 155 modname = (char *)preload_search_info(modptr, MODINFO_NAME); 156 if (modname == NULL) 157 modname = "kernel"; 158 linker_kernel_file = linker_make_file(modname, ef, &link_elf_file_ops); 159 if (linker_kernel_file == NULL) 160 panic("link_elf_init: Can't create linker structures for kernel"); 161 parse_dynamic(linker_kernel_file); 162 linker_kernel_file->address = (caddr_t) KERNBASE; 163 linker_kernel_file->size = -(intptr_t)linker_kernel_file->address; 164 165 if (modptr) { 166 ef->modptr = modptr; 167 baseptr = preload_search_info(modptr, MODINFO_ADDR); 168 if (baseptr) 169 linker_kernel_file->address = *(caddr_t *)baseptr; 170 sizeptr = preload_search_info(modptr, MODINFO_SIZE); 171 if (sizeptr) 172 linker_kernel_file->size = *(size_t *)sizeptr; 173 } 174 (void)parse_module_symbols(linker_kernel_file); 175 linker_current_file = linker_kernel_file; 176 linker_kernel_file->flags |= LINKER_FILE_LINKED; 177 } 178 #endif 179 } 180 181 SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_SECOND, link_elf_init, 0); 182 183 static int 184 parse_module_symbols(linker_file_t lf) 185 { 186 elf_file_t ef = lf->priv; 187 caddr_t pointer; 188 caddr_t ssym, esym, base; 189 caddr_t strtab; 190 int strcnt; 191 Elf_Sym* symtab; 192 int symcnt; 193 194 if (ef->modptr == NULL) 195 return 0; 196 pointer = preload_search_info(ef->modptr, MODINFO_METADATA|MODINFOMD_SSYM); 197 if (pointer == NULL) 198 return 0; 199 ssym = *(caddr_t *)pointer; 200 pointer = preload_search_info(ef->modptr, MODINFO_METADATA|MODINFOMD_ESYM); 201 if (pointer == NULL) 202 return 0; 203 esym = *(caddr_t *)pointer; 204 205 base = ssym; 206 207 symcnt = *(long *)base; 208 base += sizeof(long); 209 symtab = (Elf_Sym *)base; 210 base += roundup(symcnt, sizeof(long)); 211 212 if (base > esym || base < ssym) { 213 printf("Symbols are corrupt!\n"); 214 return EINVAL; 215 } 216 217 strcnt = *(long *)base; 218 base += sizeof(long); 219 strtab = base; 220 base += roundup(strcnt, sizeof(long)); 221 222 if (base > esym || base < ssym) { 223 printf("Symbols are corrupt!\n"); 224 return EINVAL; 225 } 226 227 ef->ddbsymtab = symtab; 228 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym); 229 ef->ddbstrtab = strtab; 230 ef->ddbstrcnt = strcnt; 231 232 return 0; 233 } 234 235 static int 236 parse_dynamic(linker_file_t lf) 237 { 238 elf_file_t ef = lf->priv; 239 const Elf_Dyn *dp; 240 int plttype = DT_REL; 241 242 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) { 243 switch (dp->d_tag) { 244 case DT_HASH: 245 { 246 /* From src/libexec/rtld-elf/rtld.c */ 247 const Elf_Off *hashtab = (const Elf_Off *) 248 (ef->address + dp->d_un.d_ptr); 249 ef->nbuckets = hashtab[0]; 250 ef->nchains = hashtab[1]; 251 ef->buckets = hashtab + 2; 252 ef->chains = ef->buckets + ef->nbuckets; 253 break; 254 } 255 case DT_STRTAB: 256 ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr); 257 break; 258 case DT_STRSZ: 259 ef->strsz = dp->d_un.d_val; 260 break; 261 case DT_SYMTAB: 262 ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr); 263 break; 264 case DT_SYMENT: 265 if (dp->d_un.d_val != sizeof(Elf_Sym)) 266 return ENOEXEC; 267 break; 268 case DT_PLTGOT: 269 ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr); 270 break; 271 case DT_REL: 272 ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr); 273 break; 274 case DT_RELSZ: 275 ef->relsize = dp->d_un.d_val; 276 break; 277 case DT_RELENT: 278 if (dp->d_un.d_val != sizeof(Elf_Rel)) 279 return ENOEXEC; 280 break; 281 case DT_JMPREL: 282 ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr); 283 break; 284 case DT_PLTRELSZ: 285 ef->pltrelsize = dp->d_un.d_val; 286 break; 287 case DT_RELA: 288 ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr); 289 break; 290 case DT_RELASZ: 291 ef->relasize = dp->d_un.d_val; 292 break; 293 case DT_RELAENT: 294 if (dp->d_un.d_val != sizeof(Elf_Rela)) 295 return ENOEXEC; 296 break; 297 case DT_PLTREL: 298 plttype = dp->d_un.d_val; 299 if (plttype != DT_REL && plttype != DT_RELA) 300 return ENOEXEC; 301 break; 302 } 303 } 304 305 if (plttype == DT_RELA) { 306 ef->pltrela = (const Elf_Rela *) ef->pltrel; 307 ef->pltrel = NULL; 308 ef->pltrelasize = ef->pltrelsize; 309 ef->pltrelsize = 0; 310 } 311 312 ef->ddbsymtab = ef->symtab; 313 ef->ddbsymcnt = ef->nchains; 314 ef->ddbstrtab = ef->strtab; 315 ef->ddbstrcnt = ef->strsz; 316 317 return 0; 318 } 319 320 static void 321 link_elf_error(const char *s) 322 { 323 printf("kldload: %s\n", s); 324 } 325 326 static int 327 link_elf_load_module(const char *filename, linker_file_t *result) 328 { 329 caddr_t modptr, baseptr, sizeptr, dynptr; 330 char *type; 331 elf_file_t ef; 332 linker_file_t lf; 333 int error; 334 vm_offset_t dp; 335 336 /* Look to see if we have the module preloaded */ 337 modptr = preload_search_by_name(filename); 338 if (modptr == NULL) 339 return (link_elf_load_file(filename, result)); 340 341 /* It's preloaded, check we can handle it and collect information */ 342 type = (char *)preload_search_info(modptr, MODINFO_TYPE); 343 baseptr = preload_search_info(modptr, MODINFO_ADDR); 344 sizeptr = preload_search_info(modptr, MODINFO_SIZE); 345 dynptr = preload_search_info(modptr, MODINFO_METADATA|MODINFOMD_DYNAMIC); 346 if (type == NULL || strcmp(type, "elf module") != 0) 347 return (EFTYPE); 348 if (baseptr == NULL || sizeptr == NULL || dynptr == NULL) 349 return (EINVAL); 350 351 ef = malloc(sizeof(struct elf_file), M_LINKER, M_WAITOK); 352 if (ef == NULL) 353 return (ENOMEM); 354 bzero(ef, sizeof(*ef)); 355 ef->modptr = modptr; 356 ef->address = *(caddr_t *)baseptr; 357 #ifdef SPARSE_MAPPING 358 ef->object = 0; 359 #endif 360 dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr; 361 ef->dynamic = (Elf_Dyn *)dp; 362 lf = linker_make_file(filename, ef, &link_elf_module_ops); 363 if (lf == NULL) { 364 free(ef, M_LINKER); 365 return ENOMEM; 366 } 367 lf->address = ef->address; 368 lf->size = *(size_t *)sizeptr; 369 370 error = parse_dynamic(lf); 371 if (error) { 372 linker_file_unload(lf); 373 return error; 374 } 375 error = load_dependancies(lf); 376 if (error) { 377 linker_file_unload(lf); 378 return error; 379 } 380 error = relocate_file(lf); 381 if (error) { 382 linker_file_unload(lf); 383 return error; 384 } 385 (void)parse_module_symbols(lf); 386 lf->flags |= LINKER_FILE_LINKED; 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 thread *td = curthread; /* XXX */ 396 struct proc *p = td->td_proc; 397 Elf_Ehdr *hdr; 398 caddr_t firstpage; 399 int nbytes, i; 400 Elf_Phdr *phdr; 401 Elf_Phdr *phlimit; 402 Elf_Phdr *segs[2]; 403 int nsegs; 404 Elf_Phdr *phdyn; 405 Elf_Phdr *phphdr; 406 caddr_t mapbase; 407 size_t mapsize; 408 Elf_Off base_offset; 409 Elf_Addr base_vaddr; 410 Elf_Addr base_vlimit; 411 int error = 0; 412 int resid; 413 elf_file_t ef; 414 linker_file_t lf; 415 char *pathname; 416 Elf_Shdr *shdr; 417 int symtabindex; 418 int symstrindex; 419 int symcnt; 420 int strcnt; 421 422 KKASSERT(p != NULL); 423 shdr = NULL; 424 lf = NULL; 425 pathname = linker_search_path(filename); 426 if (pathname == NULL) 427 return ENOENT; 428 429 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, pathname, td); 430 error = vn_open(&nd, FREAD, 0); 431 free(pathname, M_LINKER); 432 if (error) 433 return error; 434 NDFREE(&nd, NDF_ONLY_PNBUF); 435 436 /* 437 * Read the elf header from the file. 438 */ 439 firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK); 440 if (firstpage == NULL) { 441 error = ENOMEM; 442 goto out; 443 } 444 hdr = (Elf_Ehdr *)firstpage; 445 error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0, 446 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, td); 447 nbytes = PAGE_SIZE - resid; 448 if (error) 449 goto out; 450 451 if (!IS_ELF(*hdr)) { 452 error = ENOEXEC; 453 goto out; 454 } 455 456 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS 457 || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) { 458 link_elf_error("Unsupported file layout"); 459 error = ENOEXEC; 460 goto out; 461 } 462 if (hdr->e_ident[EI_VERSION] != EV_CURRENT 463 || hdr->e_version != EV_CURRENT) { 464 link_elf_error("Unsupported file version"); 465 error = ENOEXEC; 466 goto out; 467 } 468 if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) { 469 link_elf_error("Unsupported file type"); 470 error = ENOEXEC; 471 goto out; 472 } 473 if (hdr->e_machine != ELF_TARG_MACH) { 474 link_elf_error("Unsupported machine"); 475 error = ENOEXEC; 476 goto out; 477 } 478 479 /* 480 * We rely on the program header being in the first page. This is 481 * not strictly required by the ABI specification, but it seems to 482 * always true in practice. And, it simplifies things considerably. 483 */ 484 if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) && 485 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) && 486 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes))) 487 link_elf_error("Unreadable program headers"); 488 489 /* 490 * Scan the program header entries, and save key information. 491 * 492 * We rely on there being exactly two load segments, text and data, 493 * in that order. 494 */ 495 phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff); 496 phlimit = phdr + hdr->e_phnum; 497 nsegs = 0; 498 phdyn = NULL; 499 phphdr = NULL; 500 while (phdr < phlimit) { 501 switch (phdr->p_type) { 502 503 case PT_LOAD: 504 if (nsegs == 2) { 505 link_elf_error("Too many sections"); 506 error = ENOEXEC; 507 goto out; 508 } 509 segs[nsegs] = phdr; 510 ++nsegs; 511 break; 512 513 case PT_PHDR: 514 phphdr = phdr; 515 break; 516 517 case PT_DYNAMIC: 518 phdyn = phdr; 519 break; 520 } 521 522 ++phdr; 523 } 524 if (phdyn == NULL) { 525 link_elf_error("Object is not dynamically-linked"); 526 error = ENOEXEC; 527 goto out; 528 } 529 530 /* 531 * Allocate the entire address space of the object, to stake out our 532 * contiguous region, and to establish the base address for relocation. 533 */ 534 base_offset = trunc_page(segs[0]->p_offset); 535 base_vaddr = trunc_page(segs[0]->p_vaddr); 536 base_vlimit = round_page(segs[1]->p_vaddr + segs[1]->p_memsz); 537 mapsize = base_vlimit - base_vaddr; 538 539 ef = malloc(sizeof(struct elf_file), M_LINKER, M_WAITOK); 540 bzero(ef, sizeof(*ef)); 541 #ifdef SPARSE_MAPPING 542 ef->object = vm_object_allocate(OBJT_DEFAULT, mapsize >> PAGE_SHIFT); 543 if (ef->object == NULL) { 544 free(ef, M_LINKER); 545 error = ENOMEM; 546 goto out; 547 } 548 vm_object_reference(ef->object); 549 ef->address = (caddr_t) vm_map_min(kernel_map); 550 error = vm_map_find(kernel_map, ef->object, 0, 551 (vm_offset_t *) &ef->address, 552 mapsize, 1, 553 VM_PROT_ALL, VM_PROT_ALL, 0); 554 if (error) { 555 vm_object_deallocate(ef->object); 556 free(ef, M_LINKER); 557 goto out; 558 } 559 #else 560 ef->address = malloc(mapsize, M_LINKER, M_WAITOK); 561 #endif 562 mapbase = ef->address; 563 564 /* 565 * Read the text and data sections and zero the bss. 566 */ 567 for (i = 0; i < 2; i++) { 568 caddr_t segbase = mapbase + segs[i]->p_vaddr - base_vaddr; 569 error = vn_rdwr(UIO_READ, nd.ni_vp, 570 segbase, segs[i]->p_filesz, segs[i]->p_offset, 571 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, td); 572 if (error) { 573 #ifdef SPARSE_MAPPING 574 vm_map_remove(kernel_map, (vm_offset_t) ef->address, 575 (vm_offset_t) ef->address 576 + (ef->object->size << PAGE_SHIFT)); 577 vm_object_deallocate(ef->object); 578 #else 579 free(ef->address, M_LINKER); 580 #endif 581 free(ef, M_LINKER); 582 goto out; 583 } 584 bzero(segbase + segs[i]->p_filesz, 585 segs[i]->p_memsz - segs[i]->p_filesz); 586 587 #ifdef SPARSE_MAPPING 588 /* 589 * Wire down the pages 590 */ 591 vm_map_pageable(kernel_map, 592 (vm_offset_t) segbase, 593 (vm_offset_t) segbase + segs[i]->p_memsz, 594 FALSE); 595 #endif 596 } 597 598 ef->dynamic = (const Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr); 599 600 lf = linker_make_file(filename, ef, &link_elf_file_ops); 601 if (lf == NULL) { 602 #ifdef SPARSE_MAPPING 603 vm_map_remove(kernel_map, (vm_offset_t) ef->address, 604 (vm_offset_t) ef->address 605 + (ef->object->size << PAGE_SHIFT)); 606 vm_object_deallocate(ef->object); 607 #else 608 free(ef->address, M_LINKER); 609 #endif 610 free(ef, M_LINKER); 611 error = ENOMEM; 612 goto out; 613 } 614 lf->address = ef->address; 615 lf->size = mapsize; 616 617 error = parse_dynamic(lf); 618 if (error) 619 goto out; 620 error = load_dependancies(lf); 621 if (error) 622 goto out; 623 error = relocate_file(lf); 624 if (error) 625 goto out; 626 627 /* Try and load the symbol table if it's present. (you can strip it!) */ 628 nbytes = hdr->e_shnum * hdr->e_shentsize; 629 if (nbytes == 0 || hdr->e_shoff == 0) 630 goto nosyms; 631 shdr = malloc(nbytes, M_LINKER, M_WAITOK); 632 if (shdr == NULL) { 633 error = ENOMEM; 634 goto out; 635 } 636 bzero(shdr, nbytes); 637 error = vn_rdwr(UIO_READ, nd.ni_vp, 638 (caddr_t)shdr, nbytes, hdr->e_shoff, 639 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, td); 640 if (error) 641 goto out; 642 symtabindex = -1; 643 symstrindex = -1; 644 for (i = 0; i < hdr->e_shnum; i++) { 645 if (shdr[i].sh_type == SHT_SYMTAB) { 646 symtabindex = i; 647 symstrindex = shdr[i].sh_link; 648 } 649 } 650 if (symtabindex < 0 || symstrindex < 0) 651 goto nosyms; 652 653 symcnt = shdr[symtabindex].sh_size; 654 ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK); 655 strcnt = shdr[symstrindex].sh_size; 656 ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK); 657 658 if (ef->symbase == NULL || ef->strbase == NULL) { 659 error = ENOMEM; 660 goto out; 661 } 662 error = vn_rdwr(UIO_READ, nd.ni_vp, 663 ef->symbase, symcnt, shdr[symtabindex].sh_offset, 664 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, td); 665 if (error) 666 goto out; 667 error = vn_rdwr(UIO_READ, nd.ni_vp, 668 ef->strbase, strcnt, shdr[symstrindex].sh_offset, 669 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, td); 670 if (error) 671 goto out; 672 673 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym); 674 ef->ddbsymtab = (const Elf_Sym *)ef->symbase; 675 ef->ddbstrcnt = strcnt; 676 ef->ddbstrtab = ef->strbase; 677 678 lf->flags |= LINKER_FILE_LINKED; 679 680 nosyms: 681 682 *result = lf; 683 684 out: 685 if (error && lf) 686 linker_file_unload(lf); 687 if (shdr) 688 free(shdr, M_LINKER); 689 if (firstpage) 690 free(firstpage, M_LINKER); 691 VOP_UNLOCK(nd.ni_vp, 0, td); 692 vn_close(nd.ni_vp, FREAD, td); 693 694 return error; 695 } 696 697 static void 698 link_elf_unload_file(linker_file_t file) 699 { 700 elf_file_t ef = file->priv; 701 702 if (ef) { 703 #ifdef SPARSE_MAPPING 704 if (ef->object) { 705 vm_map_remove(kernel_map, (vm_offset_t) ef->address, 706 (vm_offset_t) ef->address 707 + (ef->object->size << PAGE_SHIFT)); 708 vm_object_deallocate(ef->object); 709 } 710 #else 711 if (ef->address) 712 free(ef->address, M_LINKER); 713 #endif 714 if (ef->symbase) 715 free(ef->symbase, M_LINKER); 716 if (ef->strbase) 717 free(ef->strbase, M_LINKER); 718 free(ef, M_LINKER); 719 } 720 } 721 722 static void 723 link_elf_unload_module(linker_file_t file) 724 { 725 elf_file_t ef = file->priv; 726 727 if (ef) 728 free(ef, M_LINKER); 729 if (file->filename) 730 preload_delete_name(file->filename); 731 } 732 733 static int 734 load_dependancies(linker_file_t lf) 735 { 736 elf_file_t ef = lf->priv; 737 linker_file_t lfdep; 738 char* name; 739 const Elf_Dyn *dp; 740 int error = 0; 741 742 /* 743 * All files are dependant on /kernel. 744 */ 745 if (linker_kernel_file) { 746 linker_kernel_file->refs++; 747 linker_file_add_dependancy(lf, linker_kernel_file); 748 } 749 750 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) { 751 if (dp->d_tag == DT_NEEDED) { 752 name = ef->strtab + dp->d_un.d_val; 753 754 error = linker_load_file(name, &lfdep); 755 if (error) 756 goto out; 757 error = linker_file_add_dependancy(lf, lfdep); 758 if (error) 759 goto out; 760 } 761 } 762 763 out: 764 return error; 765 } 766 767 static const char * 768 symbol_name(elf_file_t ef, Elf_Word r_info) 769 { 770 const Elf_Sym *ref; 771 772 if (ELF_R_SYM(r_info)) { 773 ref = ef->symtab + ELF_R_SYM(r_info); 774 return ef->strtab + ref->st_name; 775 } else 776 return NULL; 777 } 778 779 static int 780 relocate_file(linker_file_t lf) 781 { 782 elf_file_t ef = lf->priv; 783 const Elf_Rel *rellim; 784 const Elf_Rel *rel; 785 const Elf_Rela *relalim; 786 const Elf_Rela *rela; 787 const char *symname; 788 789 /* Perform relocations without addend if there are any: */ 790 rel = ef->rel; 791 if (rel) { 792 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize); 793 while (rel < rellim) { 794 symname = symbol_name(ef, rel->r_info); 795 if (elf_reloc(lf, rel, ELF_RELOC_REL, symname)) { 796 printf("link_elf: symbol %s undefined\n", symname); 797 return ENOENT; 798 } 799 rel++; 800 } 801 } 802 803 /* Perform relocations with addend if there are any: */ 804 rela = ef->rela; 805 if (rela) { 806 relalim = (const Elf_Rela *)((const char *)ef->rela + ef->relasize); 807 while (rela < relalim) { 808 symname = symbol_name(ef, rela->r_info); 809 if (elf_reloc(lf, rela, ELF_RELOC_RELA, symname)) { 810 printf("link_elf: symbol %s undefined\n", symname); 811 return ENOENT; 812 } 813 rela++; 814 } 815 } 816 817 /* Perform PLT relocations without addend if there are any: */ 818 rel = ef->pltrel; 819 if (rel) { 820 rellim = (const Elf_Rel *)((const char *)ef->pltrel + ef->pltrelsize); 821 while (rel < rellim) { 822 symname = symbol_name(ef, rel->r_info); 823 if (elf_reloc(lf, rel, ELF_RELOC_REL, symname)) { 824 printf("link_elf: symbol %s undefined\n", symname); 825 return ENOENT; 826 } 827 rel++; 828 } 829 } 830 831 /* Perform relocations with addend if there are any: */ 832 rela = ef->pltrela; 833 if (rela) { 834 relalim = (const Elf_Rela *)((const char *)ef->pltrela + ef->pltrelasize); 835 while (rela < relalim) { 836 symname = symbol_name(ef, rela->r_info); 837 if (elf_reloc(lf, rela, ELF_RELOC_RELA, symname)) { 838 printf("link_elf: symbol %s undefined\n", symname); 839 return ENOENT; 840 } 841 rela++; 842 } 843 } 844 845 return 0; 846 } 847 848 /* 849 * Hash function for symbol table lookup. Don't even think about changing 850 * this. It is specified by the System V ABI. 851 */ 852 static unsigned long 853 elf_hash(const char *name) 854 { 855 const unsigned char *p = (const unsigned char *) name; 856 unsigned long h = 0; 857 unsigned long g; 858 859 while (*p != '\0') { 860 h = (h << 4) + *p++; 861 if ((g = h & 0xf0000000) != 0) 862 h ^= g >> 24; 863 h &= ~g; 864 } 865 return h; 866 } 867 868 int 869 link_elf_lookup_symbol(linker_file_t lf, const char* name, c_linker_sym_t* sym) 870 { 871 elf_file_t ef = lf->priv; 872 unsigned long symnum; 873 const Elf_Sym* symp; 874 const char *strp; 875 unsigned long hash; 876 int i; 877 878 /* First, search hashed global symbols */ 879 hash = elf_hash(name); 880 symnum = ef->buckets[hash % ef->nbuckets]; 881 882 while (symnum != STN_UNDEF) { 883 if (symnum >= ef->nchains) { 884 printf("link_elf_lookup_symbol: corrupt symbol table\n"); 885 return ENOENT; 886 } 887 888 symp = ef->symtab + symnum; 889 if (symp->st_name == 0) { 890 printf("link_elf_lookup_symbol: corrupt symbol table\n"); 891 return ENOENT; 892 } 893 894 strp = ef->strtab + symp->st_name; 895 896 if (strcmp(name, strp) == 0) { 897 if (symp->st_shndx != SHN_UNDEF || 898 (symp->st_value != 0 && 899 ELF_ST_TYPE(symp->st_info) == STT_FUNC) 900 ) { 901 *sym = (c_linker_sym_t) symp; 902 return 0; 903 } else { 904 return ENOENT; 905 } 906 } 907 908 symnum = ef->chains[symnum]; 909 } 910 911 /* If we have not found it, look at the full table (if loaded) */ 912 if (ef->symtab == ef->ddbsymtab) 913 return ENOENT; 914 915 /* Exhaustive search */ 916 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 917 strp = ef->ddbstrtab + symp->st_name; 918 if (strcmp(name, strp) == 0) { 919 if (symp->st_shndx != SHN_UNDEF || 920 (symp->st_value != 0 && 921 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) { 922 *sym = (c_linker_sym_t) symp; 923 return 0; 924 } else { 925 return ENOENT; 926 } 927 } 928 } 929 return ENOENT; 930 } 931 932 static int 933 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, linker_symval_t* symval) 934 { 935 elf_file_t ef = lf->priv; 936 const Elf_Sym* es = (const Elf_Sym*) sym; 937 938 if (es >= ef->symtab && ((es - ef->symtab) < ef->nchains)) { 939 symval->name = ef->strtab + es->st_name; 940 symval->value = (caddr_t) ef->address + es->st_value; 941 symval->size = es->st_size; 942 return 0; 943 } 944 if (ef->symtab == ef->ddbsymtab) 945 return ENOENT; 946 if (es >= ef->ddbsymtab && ((es - ef->ddbsymtab) < ef->ddbsymcnt)) { 947 symval->name = ef->ddbstrtab + es->st_name; 948 symval->value = (caddr_t) ef->address + es->st_value; 949 symval->size = es->st_size; 950 return 0; 951 } 952 return ENOENT; 953 } 954 955 static int 956 link_elf_search_symbol(linker_file_t lf, caddr_t value, 957 c_linker_sym_t* sym, long* diffp) 958 { 959 elf_file_t ef = lf->priv; 960 u_long off = (uintptr_t) (void *) value; 961 u_long diff = off; 962 u_long st_value; 963 const Elf_Sym* es; 964 const Elf_Sym* best = 0; 965 int i; 966 967 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) { 968 if (es->st_name == 0) 969 continue; 970 st_value = es->st_value + (uintptr_t) (void *) ef->address; 971 if (off >= st_value) { 972 if (off - st_value < diff) { 973 diff = off - st_value; 974 best = es; 975 if (diff == 0) 976 break; 977 } else if (off - st_value == diff) { 978 best = es; 979 } 980 } 981 } 982 if (best == 0) 983 *diffp = off; 984 else 985 *diffp = diff; 986 *sym = (c_linker_sym_t) best; 987 988 return 0; 989 } 990