1 /*- 2 * Copyright (c) 1998-2000 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 "opt_ddb.h" 30 31 #include <sys/param.h> 32 #include <sys/kernel.h> 33 #include <sys/systm.h> 34 #include <sys/malloc.h> 35 #include <sys/proc.h> 36 #include <sys/namei.h> 37 #include <sys/fcntl.h> 38 #include <sys/vnode.h> 39 #include <sys/linker.h> 40 #include <machine/elf.h> 41 42 #include <vm/vm.h> 43 #include <vm/vm_param.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 #ifdef __AOUT__ 53 #include <nlist.h> 54 #endif 55 #include <link.h> 56 57 #include "linker_if.h" 58 59 typedef struct elf_file { 60 struct linker_file lf; /* Common fields */ 61 int preloaded; /* Was file pre-loaded */ 62 caddr_t address; /* Relocation address */ 63 #ifdef SPARSE_MAPPING 64 vm_object_t object; /* VM object to hold file pages */ 65 #endif 66 Elf_Dyn* dynamic; /* Symbol table etc. */ 67 Elf_Off nbuckets; /* DT_HASH info */ 68 Elf_Off nchains; 69 const Elf_Off* buckets; 70 const Elf_Off* chains; 71 caddr_t hash; 72 caddr_t strtab; /* DT_STRTAB */ 73 int strsz; /* DT_STRSZ */ 74 const Elf_Sym* symtab; /* DT_SYMTAB */ 75 Elf_Addr* got; /* DT_PLTGOT */ 76 const Elf_Rel* pltrel; /* DT_JMPREL */ 77 int pltrelsize; /* DT_PLTRELSZ */ 78 const Elf_Rela* pltrela; /* DT_JMPREL */ 79 int pltrelasize; /* DT_PLTRELSZ */ 80 const Elf_Rel* rel; /* DT_REL */ 81 int relsize; /* DT_RELSZ */ 82 const Elf_Rela* rela; /* DT_RELA */ 83 int relasize; /* DT_RELASZ */ 84 caddr_t modptr; 85 const Elf_Sym* ddbsymtab; /* The symbol table we are using */ 86 long ddbsymcnt; /* Number of symbols */ 87 caddr_t ddbstrtab; /* String table */ 88 long ddbstrcnt; /* number of bytes in string table */ 89 caddr_t symbase; /* malloc'ed symbold base */ 90 caddr_t strbase; /* malloc'ed string base */ 91 #ifdef DDB 92 struct link_map gdb; /* hooks for gdb */ 93 #endif 94 } *elf_file_t; 95 96 static int link_elf_link_preload(linker_class_t cls, 97 const char*, linker_file_t*); 98 static int link_elf_link_preload_finish(linker_file_t); 99 static int link_elf_load_file(linker_class_t, const char*, linker_file_t*); 100 static int link_elf_lookup_symbol(linker_file_t, const char*, 101 c_linker_sym_t*); 102 static int link_elf_symbol_values(linker_file_t, c_linker_sym_t, linker_symval_t*); 103 static int link_elf_search_symbol(linker_file_t, caddr_t value, 104 c_linker_sym_t* sym, long* diffp); 105 106 static void link_elf_unload_file(linker_file_t); 107 static void link_elf_unload_preload(linker_file_t); 108 109 static kobj_method_t link_elf_methods[] = { 110 KOBJMETHOD(linker_lookup_symbol, link_elf_lookup_symbol), 111 KOBJMETHOD(linker_symbol_values, link_elf_symbol_values), 112 KOBJMETHOD(linker_search_symbol, link_elf_search_symbol), 113 KOBJMETHOD(linker_unload, link_elf_unload_file), 114 KOBJMETHOD(linker_load_file, link_elf_load_file), 115 KOBJMETHOD(linker_link_preload, link_elf_link_preload), 116 KOBJMETHOD(linker_link_preload_finish, link_elf_link_preload_finish), 117 { 0, 0 } 118 }; 119 120 static struct linker_class link_elf_class = { 121 #if ELF_TARG_CLASS == ELFCLASS32 122 "elf32", 123 #else 124 "elf64", 125 #endif 126 link_elf_methods, sizeof(struct elf_file) 127 }; 128 129 static int parse_dynamic(elf_file_t ef); 130 static int relocate_file(elf_file_t ef); 131 static int link_elf_preload_parse_symbols(elf_file_t ef); 132 133 #ifdef DDB 134 static void r_debug_state(struct r_debug *dummy_one, 135 struct link_map *dummy_two); 136 137 /* 138 * A list of loaded modules for GDB to use for loading symbols. 139 */ 140 struct r_debug r_debug; 141 142 #define GDB_STATE(s) r_debug.r_state = s; r_debug_state(NULL, NULL); 143 144 /* 145 * Function for the debugger to set a breakpoint on to gain control. 146 */ 147 void 148 r_debug_state(struct r_debug *dummy_one __unused, 149 struct link_map *dummy_two __unused) 150 { 151 } 152 153 #endif 154 155 /* 156 * The kernel symbol table starts here. 157 */ 158 #ifndef __ia64__ 159 extern struct _dynamic _DYNAMIC; 160 #endif 161 162 static void 163 link_elf_init(void* arg) 164 { 165 #ifdef __ELF__ 166 Elf_Dyn *dp; 167 caddr_t modptr, baseptr, sizeptr; 168 elf_file_t ef; 169 char *modname; 170 #endif 171 172 linker_add_class(&link_elf_class); 173 174 #ifdef __ELF__ 175 #ifndef __ia64__ 176 dp = (Elf_Dyn*) &_DYNAMIC; 177 #else 178 dp = 0; 179 #endif 180 if (dp) { 181 modname = NULL; 182 modptr = preload_search_by_type("elf kernel"); 183 if (modptr) 184 modname = (char *)preload_search_info(modptr, MODINFO_NAME); 185 if (modname == NULL) 186 modname = "kernel"; 187 linker_kernel_file = linker_make_file(modname, &link_elf_class); 188 if (linker_kernel_file == NULL) 189 panic("link_elf_init: Can't create linker structures for kernel"); 190 191 ef = (elf_file_t) linker_kernel_file; 192 ef->preloaded = 1; 193 ef->address = 0; 194 #ifdef SPARSE_MAPPING 195 ef->object = 0; 196 #endif 197 ef->dynamic = dp; 198 199 parse_dynamic(ef); 200 linker_kernel_file->address = (caddr_t) KERNBASE; 201 linker_kernel_file->size = -(intptr_t)linker_kernel_file->address; 202 203 if (modptr) { 204 ef->modptr = modptr; 205 baseptr = preload_search_info(modptr, MODINFO_ADDR); 206 if (baseptr) 207 linker_kernel_file->address = *(caddr_t *)baseptr; 208 sizeptr = preload_search_info(modptr, MODINFO_SIZE); 209 if (sizeptr) 210 linker_kernel_file->size = *(size_t *)sizeptr; 211 } 212 (void)link_elf_preload_parse_symbols(ef); 213 214 #ifdef DDB 215 ef->gdb.l_addr = linker_kernel_file->address; 216 ef->gdb.l_name = modname; 217 ef->gdb.l_ld = dp; 218 ef->gdb.l_prev = 0; 219 ef->gdb.l_next = 0; 220 221 r_debug.r_map = &ef->gdb; 222 r_debug.r_brk = r_debug_state; 223 r_debug.r_state = RT_CONSISTENT; 224 225 r_debug_state(NULL, NULL); /* say hello to gdb! */ 226 #endif 227 228 } 229 #endif 230 } 231 232 SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_SECOND, link_elf_init, 0); 233 234 static int 235 link_elf_preload_parse_symbols(elf_file_t ef) 236 { 237 caddr_t pointer; 238 caddr_t ssym, esym, base; 239 caddr_t strtab; 240 int strcnt; 241 Elf_Sym* symtab; 242 int symcnt; 243 244 if (ef->modptr == NULL) 245 return 0; 246 pointer = preload_search_info(ef->modptr, MODINFO_METADATA|MODINFOMD_SSYM); 247 if (pointer == NULL) 248 return 0; 249 ssym = *(caddr_t *)pointer; 250 pointer = preload_search_info(ef->modptr, MODINFO_METADATA|MODINFOMD_ESYM); 251 if (pointer == NULL) 252 return 0; 253 esym = *(caddr_t *)pointer; 254 255 base = ssym; 256 257 symcnt = *(long *)base; 258 base += sizeof(long); 259 symtab = (Elf_Sym *)base; 260 base += roundup(symcnt, sizeof(long)); 261 262 if (base > esym || base < ssym) { 263 printf("Symbols are corrupt!\n"); 264 return EINVAL; 265 } 266 267 strcnt = *(long *)base; 268 base += sizeof(long); 269 strtab = base; 270 base += roundup(strcnt, sizeof(long)); 271 272 if (base > esym || base < ssym) { 273 printf("Symbols are corrupt!\n"); 274 return EINVAL; 275 } 276 277 ef->ddbsymtab = symtab; 278 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym); 279 ef->ddbstrtab = strtab; 280 ef->ddbstrcnt = strcnt; 281 282 return 0; 283 } 284 285 static int 286 parse_dynamic(elf_file_t ef) 287 { 288 Elf_Dyn *dp; 289 int plttype = DT_REL; 290 291 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) { 292 switch (dp->d_tag) { 293 case DT_HASH: 294 { 295 /* From src/libexec/rtld-elf/rtld.c */ 296 const Elf_Off *hashtab = (const Elf_Off *) 297 (ef->address + dp->d_un.d_ptr); 298 ef->nbuckets = hashtab[0]; 299 ef->nchains = hashtab[1]; 300 ef->buckets = hashtab + 2; 301 ef->chains = ef->buckets + ef->nbuckets; 302 break; 303 } 304 case DT_STRTAB: 305 ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr); 306 break; 307 case DT_STRSZ: 308 ef->strsz = dp->d_un.d_val; 309 break; 310 case DT_SYMTAB: 311 ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr); 312 break; 313 case DT_SYMENT: 314 if (dp->d_un.d_val != sizeof(Elf_Sym)) 315 return ENOEXEC; 316 break; 317 case DT_PLTGOT: 318 ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr); 319 break; 320 case DT_REL: 321 ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr); 322 break; 323 case DT_RELSZ: 324 ef->relsize = dp->d_un.d_val; 325 break; 326 case DT_RELENT: 327 if (dp->d_un.d_val != sizeof(Elf_Rel)) 328 return ENOEXEC; 329 break; 330 case DT_JMPREL: 331 ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr); 332 break; 333 case DT_PLTRELSZ: 334 ef->pltrelsize = dp->d_un.d_val; 335 break; 336 case DT_RELA: 337 ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr); 338 break; 339 case DT_RELASZ: 340 ef->relasize = dp->d_un.d_val; 341 break; 342 case DT_RELAENT: 343 if (dp->d_un.d_val != sizeof(Elf_Rela)) 344 return ENOEXEC; 345 break; 346 case DT_PLTREL: 347 plttype = dp->d_un.d_val; 348 if (plttype != DT_REL && plttype != DT_RELA) 349 return ENOEXEC; 350 break; 351 #ifdef DDB 352 case DT_DEBUG: 353 dp->d_un.d_ptr = (Elf_Addr) &r_debug; 354 break; 355 #endif 356 } 357 } 358 359 if (plttype == DT_RELA) { 360 ef->pltrela = (const Elf_Rela *) ef->pltrel; 361 ef->pltrel = NULL; 362 ef->pltrelasize = ef->pltrelsize; 363 ef->pltrelsize = 0; 364 } 365 366 ef->ddbsymtab = ef->symtab; 367 ef->ddbsymcnt = ef->nchains; 368 ef->ddbstrtab = ef->strtab; 369 ef->ddbstrcnt = ef->strsz; 370 371 return 0; 372 } 373 374 static void 375 link_elf_error(const char *s) 376 { 377 printf("kldload: %s\n", s); 378 } 379 380 #ifdef DDB 381 382 static void 383 link_elf_add_gdb(struct link_map *l) 384 { 385 struct link_map *prev; 386 387 /* 388 * Scan to the end of the list. 389 */ 390 for (prev = r_debug.r_map; prev->l_next != NULL; prev = prev->l_next) 391 ; 392 393 /* Link in the new entry. */ 394 l->l_prev = prev; 395 l->l_next = prev->l_next; 396 prev->l_next = l; 397 } 398 399 static void 400 link_elf_delete_gdb(struct link_map *l) 401 { 402 if (l->l_prev == NULL) { 403 if ((r_debug.r_map = l->l_next) != NULL) 404 l->l_next->l_prev = NULL; 405 return; 406 } 407 408 if ((l->l_prev->l_next = l->l_next) != NULL) 409 l->l_next->l_prev = l->l_prev; 410 } 411 412 #endif /* DDB */ 413 414 static int 415 link_elf_link_preload(linker_class_t cls, 416 const char* filename, linker_file_t *result) 417 { 418 caddr_t modptr, baseptr, sizeptr, dynptr; 419 char *type; 420 elf_file_t ef; 421 linker_file_t lf; 422 int error; 423 vm_offset_t dp; 424 425 /* Look to see if we have the file preloaded */ 426 modptr = preload_search_by_name(filename); 427 if (modptr == NULL) 428 return ENOENT; 429 430 type = (char *)preload_search_info(modptr, MODINFO_TYPE); 431 baseptr = preload_search_info(modptr, MODINFO_ADDR); 432 sizeptr = preload_search_info(modptr, MODINFO_SIZE); 433 dynptr = preload_search_info(modptr, MODINFO_METADATA|MODINFOMD_DYNAMIC); 434 if (type == NULL || strcmp(type, "elf module") != 0) 435 return (EFTYPE); 436 if (baseptr == NULL || sizeptr == NULL || dynptr == NULL) 437 return (EINVAL); 438 439 lf = linker_make_file(filename, &link_elf_class); 440 if (lf == NULL) { 441 return ENOMEM; 442 } 443 444 ef = (elf_file_t) lf; 445 ef->preloaded = 1; 446 ef->modptr = modptr; 447 ef->address = *(caddr_t *)baseptr; 448 #ifdef SPARSE_MAPPING 449 ef->object = 0; 450 #endif 451 dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr; 452 ef->dynamic = (Elf_Dyn *)dp; 453 lf->address = ef->address; 454 lf->size = *(size_t *)sizeptr; 455 456 error = parse_dynamic(ef); 457 if (error) { 458 linker_file_unload(lf); 459 return error; 460 } 461 *result = lf; 462 return (0); 463 } 464 465 static int 466 link_elf_link_preload_finish(linker_file_t lf) 467 { 468 elf_file_t ef; 469 int error; 470 471 ef = (elf_file_t) lf; 472 #if 0 /* this will be more trouble than it's worth for now */ 473 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) { 474 if (dp->d_tag != DT_NEEDED) 475 continue; 476 modname = ef->strtab + dp->d_un.d_val; 477 error = linker_load_module(modname, lf); 478 if (error) 479 goto out; 480 } 481 #endif 482 error = relocate_file(ef); 483 if (error) 484 return error; 485 (void)link_elf_preload_parse_symbols(ef); 486 487 #ifdef DDB 488 GDB_STATE(RT_ADD); 489 ef->gdb.l_addr = lf->address; 490 ef->gdb.l_name = lf->filename; 491 ef->gdb.l_ld = ef->dynamic; 492 link_elf_add_gdb(&ef->gdb); 493 GDB_STATE(RT_CONSISTENT); 494 #endif 495 496 return (0); 497 } 498 499 static int 500 link_elf_load_file(linker_class_t cls, const char* filename, linker_file_t* result) 501 { 502 struct nameidata nd; 503 struct proc* p = curproc; /* XXX */ 504 Elf_Ehdr *hdr; 505 caddr_t firstpage; 506 int nbytes, i; 507 Elf_Phdr *phdr; 508 Elf_Phdr *phlimit; 509 Elf_Phdr *segs[2]; 510 int nsegs; 511 Elf_Phdr *phdyn; 512 Elf_Phdr *phphdr; 513 caddr_t mapbase; 514 size_t mapsize; 515 Elf_Off base_offset; 516 Elf_Addr base_vaddr; 517 Elf_Addr base_vlimit; 518 int error = 0; 519 int resid, flags; 520 elf_file_t ef; 521 linker_file_t lf; 522 Elf_Shdr *shdr; 523 int symtabindex; 524 int symstrindex; 525 int symcnt; 526 int strcnt; 527 528 shdr = NULL; 529 lf = NULL; 530 531 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, p); 532 flags = FREAD; 533 error = vn_open(&nd, &flags, 0); 534 if (error) 535 return error; 536 NDFREE(&nd, NDF_ONLY_PNBUF); 537 538 /* 539 * Read the elf header from the file. 540 */ 541 firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK); 542 if (firstpage == NULL) { 543 error = ENOMEM; 544 goto out; 545 } 546 hdr = (Elf_Ehdr *)firstpage; 547 error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0, 548 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, p); 549 nbytes = PAGE_SIZE - resid; 550 if (error) 551 goto out; 552 553 if (!IS_ELF(*hdr)) { 554 error = ENOEXEC; 555 goto out; 556 } 557 558 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS 559 || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) { 560 link_elf_error("Unsupported file layout"); 561 error = ENOEXEC; 562 goto out; 563 } 564 if (hdr->e_ident[EI_VERSION] != EV_CURRENT 565 || hdr->e_version != EV_CURRENT) { 566 link_elf_error("Unsupported file version"); 567 error = ENOEXEC; 568 goto out; 569 } 570 if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) { 571 link_elf_error("Unsupported file type"); 572 error = ENOEXEC; 573 goto out; 574 } 575 if (hdr->e_machine != ELF_TARG_MACH) { 576 link_elf_error("Unsupported machine"); 577 error = ENOEXEC; 578 goto out; 579 } 580 581 /* 582 * We rely on the program header being in the first page. This is 583 * not strictly required by the ABI specification, but it seems to 584 * always true in practice. And, it simplifies things considerably. 585 */ 586 if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) && 587 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) && 588 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes))) 589 link_elf_error("Unreadable program headers"); 590 591 /* 592 * Scan the program header entries, and save key information. 593 * 594 * We rely on there being exactly two load segments, text and data, 595 * in that order. 596 */ 597 phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff); 598 phlimit = phdr + hdr->e_phnum; 599 nsegs = 0; 600 phdyn = NULL; 601 phphdr = NULL; 602 while (phdr < phlimit) { 603 switch (phdr->p_type) { 604 605 case PT_LOAD: 606 if (nsegs == 2) { 607 link_elf_error("Too many sections"); 608 error = ENOEXEC; 609 goto out; 610 } 611 segs[nsegs] = phdr; 612 ++nsegs; 613 break; 614 615 case PT_PHDR: 616 phphdr = phdr; 617 break; 618 619 case PT_DYNAMIC: 620 phdyn = phdr; 621 break; 622 623 case PT_INTERP: 624 link_elf_error("Unsupported file type"); 625 error = ENOEXEC; 626 goto out; 627 } 628 629 ++phdr; 630 } 631 if (phdyn == NULL) { 632 link_elf_error("Object is not dynamically-linked"); 633 error = ENOEXEC; 634 goto out; 635 } 636 637 /* 638 * Allocate the entire address space of the object, to stake out our 639 * contiguous region, and to establish the base address for relocation. 640 */ 641 base_offset = trunc_page(segs[0]->p_offset); 642 base_vaddr = trunc_page(segs[0]->p_vaddr); 643 base_vlimit = round_page(segs[1]->p_vaddr + segs[1]->p_memsz); 644 mapsize = base_vlimit - base_vaddr; 645 646 lf = linker_make_file(filename, &link_elf_class); 647 if (!lf) { 648 error = ENOMEM; 649 goto out; 650 } 651 652 ef = (elf_file_t) lf; 653 #ifdef SPARSE_MAPPING 654 ef->object = vm_object_allocate(OBJT_DEFAULT, mapsize >> PAGE_SHIFT); 655 if (ef->object == NULL) { 656 free(ef, M_LINKER); 657 error = ENOMEM; 658 goto out; 659 } 660 vm_object_reference(ef->object); 661 ef->address = (caddr_t) vm_map_min(kernel_map); 662 error = vm_map_find(kernel_map, ef->object, 0, 663 (vm_offset_t *) &ef->address, 664 mapsize, 1, 665 VM_PROT_ALL, VM_PROT_ALL, 0); 666 if (error) { 667 vm_object_deallocate(ef->object); 668 ef->object = 0; 669 goto out; 670 } 671 #else 672 ef->address = malloc(mapsize, M_LINKER, M_WAITOK); 673 if (!ef->address) { 674 error = ENOMEM; 675 goto out; 676 } 677 #endif 678 mapbase = ef->address; 679 680 /* 681 * Read the text and data sections and zero the bss. 682 */ 683 for (i = 0; i < 2; i++) { 684 caddr_t segbase = mapbase + segs[i]->p_vaddr - base_vaddr; 685 error = vn_rdwr(UIO_READ, nd.ni_vp, 686 segbase, segs[i]->p_filesz, segs[i]->p_offset, 687 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, p); 688 if (error) { 689 goto out; 690 } 691 bzero(segbase + segs[i]->p_filesz, 692 segs[i]->p_memsz - segs[i]->p_filesz); 693 694 #ifdef SPARSE_MAPPING 695 /* 696 * Wire down the pages 697 */ 698 vm_map_pageable(kernel_map, 699 (vm_offset_t) segbase, 700 (vm_offset_t) segbase + segs[i]->p_memsz, 701 FALSE); 702 #endif 703 } 704 705 ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr); 706 707 lf->address = ef->address; 708 lf->size = mapsize; 709 710 error = parse_dynamic(ef); 711 if (error) 712 goto out; 713 error = linker_load_dependancies(lf); 714 if (error) 715 goto out; 716 #if 0 /* this will be more trouble than it's worth for now */ 717 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) { 718 if (dp->d_tag != DT_NEEDED) 719 continue; 720 modname = ef->strtab + dp->d_un.d_val; 721 error = linker_load_module(modname, lf); 722 if (error) 723 goto out; 724 } 725 #endif 726 error = relocate_file(ef); 727 if (error) 728 goto out; 729 730 /* Try and load the symbol table if it's present. (you can strip it!) */ 731 nbytes = hdr->e_shnum * hdr->e_shentsize; 732 if (nbytes == 0 || hdr->e_shoff == 0) 733 goto nosyms; 734 shdr = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO); 735 if (shdr == NULL) { 736 error = ENOMEM; 737 goto out; 738 } 739 error = vn_rdwr(UIO_READ, nd.ni_vp, 740 (caddr_t)shdr, nbytes, hdr->e_shoff, 741 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, p); 742 if (error) 743 goto out; 744 symtabindex = -1; 745 symstrindex = -1; 746 for (i = 0; i < hdr->e_shnum; i++) { 747 if (shdr[i].sh_type == SHT_SYMTAB) { 748 symtabindex = i; 749 symstrindex = shdr[i].sh_link; 750 } 751 } 752 if (symtabindex < 0 || symstrindex < 0) 753 goto nosyms; 754 755 symcnt = shdr[symtabindex].sh_size; 756 ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK); 757 strcnt = shdr[symstrindex].sh_size; 758 ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK); 759 760 if (ef->symbase == NULL || ef->strbase == NULL) { 761 error = ENOMEM; 762 goto out; 763 } 764 error = vn_rdwr(UIO_READ, nd.ni_vp, 765 ef->symbase, symcnt, shdr[symtabindex].sh_offset, 766 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, p); 767 if (error) 768 goto out; 769 error = vn_rdwr(UIO_READ, nd.ni_vp, 770 ef->strbase, strcnt, shdr[symstrindex].sh_offset, 771 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, p); 772 if (error) 773 goto out; 774 775 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym); 776 ef->ddbsymtab = (const Elf_Sym *)ef->symbase; 777 ef->ddbstrcnt = strcnt; 778 ef->ddbstrtab = ef->strbase; 779 780 #ifdef DDB 781 GDB_STATE(RT_ADD); 782 ef->gdb.l_addr = lf->address; 783 ef->gdb.l_name = filename; 784 ef->gdb.l_ld = ef->dynamic; 785 link_elf_add_gdb(&ef->gdb); 786 GDB_STATE(RT_CONSISTENT); 787 #endif 788 789 nosyms: 790 791 *result = lf; 792 793 out: 794 if (error && lf) 795 linker_file_unload(lf); 796 if (shdr) 797 free(shdr, M_LINKER); 798 if (firstpage) 799 free(firstpage, M_LINKER); 800 VOP_UNLOCK(nd.ni_vp, 0, p); 801 vn_close(nd.ni_vp, FREAD, p->p_ucred, p); 802 803 return error; 804 } 805 806 static void 807 link_elf_unload_file(linker_file_t file) 808 { 809 elf_file_t ef = (elf_file_t) file; 810 811 #ifdef DDB 812 if (ef->gdb.l_ld) { 813 GDB_STATE(RT_DELETE); 814 link_elf_delete_gdb(&ef->gdb); 815 GDB_STATE(RT_CONSISTENT); 816 } 817 #endif 818 819 if (ef->preloaded) { 820 link_elf_unload_preload(file); 821 return; 822 } 823 #ifdef SPARSE_MAPPING 824 if (ef->object) { 825 vm_map_remove(kernel_map, (vm_offset_t) ef->address, 826 (vm_offset_t) ef->address 827 + (ef->object->size << PAGE_SHIFT)); 828 vm_object_deallocate(ef->object); 829 } 830 #else 831 if (ef->address) 832 free(ef->address, M_LINKER); 833 #endif 834 if (ef->symbase) 835 free(ef->symbase, M_LINKER); 836 if (ef->strbase) 837 free(ef->strbase, M_LINKER); 838 } 839 840 static void 841 link_elf_unload_preload(linker_file_t file) 842 { 843 if (file->filename) 844 preload_delete_name(file->filename); 845 } 846 847 static const char * 848 symbol_name(elf_file_t ef, Elf_Word r_info) 849 { 850 const Elf_Sym *ref; 851 852 if (ELF_R_SYM(r_info)) { 853 ref = ef->symtab + ELF_R_SYM(r_info); 854 return ef->strtab + ref->st_name; 855 } else 856 return NULL; 857 } 858 859 static int 860 relocate_file(elf_file_t ef) 861 { 862 const Elf_Rel *rellim; 863 const Elf_Rel *rel; 864 const Elf_Rela *relalim; 865 const Elf_Rela *rela; 866 const char *symname; 867 868 /* Perform relocations without addend if there are any: */ 869 rel = ef->rel; 870 if (rel) { 871 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize); 872 while (rel < rellim) { 873 symname = symbol_name(ef, rel->r_info); 874 if (elf_reloc(&ef->lf, rel, ELF_RELOC_REL, symname)) { 875 printf("link_elf: symbol %s undefined\n", symname); 876 return ENOENT; 877 } 878 rel++; 879 } 880 } 881 882 /* Perform relocations with addend if there are any: */ 883 rela = ef->rela; 884 if (rela) { 885 relalim = (const Elf_Rela *)((const char *)ef->rela + ef->relasize); 886 while (rela < relalim) { 887 symname = symbol_name(ef, rela->r_info); 888 if (elf_reloc(&ef->lf, rela, ELF_RELOC_RELA, symname)) { 889 printf("link_elf: symbol %s undefined\n", symname); 890 return ENOENT; 891 } 892 rela++; 893 } 894 } 895 896 /* Perform PLT relocations without addend if there are any: */ 897 rel = ef->pltrel; 898 if (rel) { 899 rellim = (const Elf_Rel *)((const char *)ef->pltrel + ef->pltrelsize); 900 while (rel < rellim) { 901 symname = symbol_name(ef, rel->r_info); 902 if (elf_reloc(&ef->lf, rel, ELF_RELOC_REL, symname)) { 903 printf("link_elf: symbol %s undefined\n", symname); 904 return ENOENT; 905 } 906 rel++; 907 } 908 } 909 910 /* Perform relocations with addend if there are any: */ 911 rela = ef->pltrela; 912 if (rela) { 913 relalim = (const Elf_Rela *)((const char *)ef->pltrela + ef->pltrelasize); 914 while (rela < relalim) { 915 symname = symbol_name(ef, rela->r_info); 916 if (elf_reloc(&ef->lf, rela, ELF_RELOC_RELA, symname)) { 917 printf("link_elf: symbol %s undefined\n", symname); 918 return ENOENT; 919 } 920 rela++; 921 } 922 } 923 924 return 0; 925 } 926 927 /* 928 * Hash function for symbol table lookup. Don't even think about changing 929 * this. It is specified by the System V ABI. 930 */ 931 static unsigned long 932 elf_hash(const char *name) 933 { 934 const unsigned char *p = (const unsigned char *) name; 935 unsigned long h = 0; 936 unsigned long g; 937 938 while (*p != '\0') { 939 h = (h << 4) + *p++; 940 if ((g = h & 0xf0000000) != 0) 941 h ^= g >> 24; 942 h &= ~g; 943 } 944 return h; 945 } 946 947 int 948 link_elf_lookup_symbol(linker_file_t lf, const char* name, c_linker_sym_t* sym) 949 { 950 elf_file_t ef = (elf_file_t) lf; 951 unsigned long symnum; 952 const Elf_Sym* symp; 953 const char *strp; 954 unsigned long hash; 955 int i; 956 957 /* First, search hashed global symbols */ 958 hash = elf_hash(name); 959 symnum = ef->buckets[hash % ef->nbuckets]; 960 961 while (symnum != STN_UNDEF) { 962 if (symnum >= ef->nchains) { 963 printf("link_elf_lookup_symbol: corrupt symbol table\n"); 964 return ENOENT; 965 } 966 967 symp = ef->symtab + symnum; 968 if (symp->st_name == 0) { 969 printf("link_elf_lookup_symbol: corrupt symbol table\n"); 970 return ENOENT; 971 } 972 973 strp = ef->strtab + symp->st_name; 974 975 if (strcmp(name, strp) == 0) { 976 if (symp->st_shndx != SHN_UNDEF || 977 (symp->st_value != 0 && 978 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) { 979 *sym = (c_linker_sym_t) symp; 980 return 0; 981 } else 982 return ENOENT; 983 } 984 985 symnum = ef->chains[symnum]; 986 } 987 988 /* If we have not found it, look at the full table (if loaded) */ 989 if (ef->symtab == ef->ddbsymtab) 990 return ENOENT; 991 992 /* Exhaustive search */ 993 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 994 strp = ef->ddbstrtab + symp->st_name; 995 if (strcmp(name, strp) == 0) { 996 if (symp->st_shndx != SHN_UNDEF || 997 (symp->st_value != 0 && 998 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) { 999 *sym = (c_linker_sym_t) symp; 1000 return 0; 1001 } else 1002 return ENOENT; 1003 } 1004 } 1005 1006 return ENOENT; 1007 } 1008 1009 static int 1010 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, linker_symval_t* symval) 1011 { 1012 elf_file_t ef = (elf_file_t) lf; 1013 const Elf_Sym* es = (const Elf_Sym*) sym; 1014 1015 if (es >= ef->symtab && ((es - ef->symtab) < ef->nchains)) { 1016 symval->name = ef->strtab + es->st_name; 1017 symval->value = (caddr_t) ef->address + es->st_value; 1018 symval->size = es->st_size; 1019 return 0; 1020 } 1021 if (ef->symtab == ef->ddbsymtab) 1022 return ENOENT; 1023 if (es >= ef->ddbsymtab && ((es - ef->ddbsymtab) < ef->ddbsymcnt)) { 1024 symval->name = ef->ddbstrtab + es->st_name; 1025 symval->value = (caddr_t) ef->address + es->st_value; 1026 symval->size = es->st_size; 1027 return 0; 1028 } 1029 return ENOENT; 1030 } 1031 1032 static int 1033 link_elf_search_symbol(linker_file_t lf, caddr_t value, 1034 c_linker_sym_t* sym, long* diffp) 1035 { 1036 elf_file_t ef = (elf_file_t) lf; 1037 u_long off = (uintptr_t) (void *) value; 1038 u_long diff = off; 1039 u_long st_value; 1040 const Elf_Sym* es; 1041 const Elf_Sym* best = 0; 1042 int i; 1043 1044 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) { 1045 if (es->st_name == 0) 1046 continue; 1047 st_value = es->st_value + (uintptr_t) (void *) ef->address; 1048 if (off >= st_value) { 1049 if (off - st_value < diff) { 1050 diff = off - st_value; 1051 best = es; 1052 if (diff == 0) 1053 break; 1054 } else if (off - st_value == diff) { 1055 best = es; 1056 } 1057 } 1058 } 1059 if (best == 0) 1060 *diffp = off; 1061 else 1062 *diffp = diff; 1063 *sym = (c_linker_sym_t) best; 1064 1065 return 0; 1066 } 1067