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/systm.h> 33 #include <sys/kernel.h> 34 #include <sys/lock.h> 35 #include <sys/malloc.h> 36 #include <sys/proc.h> 37 #include <sys/namei.h> 38 #include <sys/fcntl.h> 39 #include <sys/vnode.h> 40 #include <sys/linker.h> 41 42 #include <machine/elf.h> 43 44 #include <vm/vm.h> 45 #include <vm/vm_param.h> 46 #ifdef SPARSE_MAPPING 47 #include <vm/vm_object.h> 48 #include <vm/vm_kern.h> 49 #include <vm/vm_extern.h> 50 #endif 51 #include <vm/pmap.h> 52 #include <vm/vm_map.h> 53 54 #ifdef __AOUT__ 55 #include <nlist.h> 56 #endif 57 #include <link.h> 58 59 #include "linker_if.h" 60 61 typedef struct elf_file { 62 struct linker_file lf; /* Common fields */ 63 int preloaded; /* Was file pre-loaded */ 64 caddr_t address; /* Relocation address */ 65 #ifdef SPARSE_MAPPING 66 vm_object_t object; /* VM object to hold file pages */ 67 #endif 68 Elf_Dyn* dynamic; /* Symbol table etc. */ 69 Elf_Off nbuckets; /* DT_HASH info */ 70 Elf_Off nchains; 71 const Elf_Off* buckets; 72 const Elf_Off* chains; 73 caddr_t hash; 74 caddr_t strtab; /* DT_STRTAB */ 75 int strsz; /* DT_STRSZ */ 76 const Elf_Sym* symtab; /* DT_SYMTAB */ 77 Elf_Addr* got; /* DT_PLTGOT */ 78 const Elf_Rel* pltrel; /* DT_JMPREL */ 79 int pltrelsize; /* DT_PLTRELSZ */ 80 const Elf_Rela* pltrela; /* DT_JMPREL */ 81 int pltrelasize; /* DT_PLTRELSZ */ 82 const Elf_Rel* rel; /* DT_REL */ 83 int relsize; /* DT_RELSZ */ 84 const Elf_Rela* rela; /* DT_RELA */ 85 int relasize; /* DT_RELASZ */ 86 caddr_t modptr; 87 const Elf_Sym* ddbsymtab; /* The symbol table we are using */ 88 long ddbsymcnt; /* Number of symbols */ 89 caddr_t ddbstrtab; /* String table */ 90 long ddbstrcnt; /* number of bytes in string table */ 91 caddr_t symbase; /* malloc'ed symbold base */ 92 caddr_t strbase; /* malloc'ed string base */ 93 #ifdef DDB 94 struct link_map gdb; /* hooks for gdb */ 95 #endif 96 } *elf_file_t; 97 98 static int link_elf_link_preload(linker_class_t cls, 99 const char*, linker_file_t*); 100 static int link_elf_link_preload_finish(linker_file_t); 101 static int link_elf_load_file(linker_class_t, const char*, linker_file_t*); 102 static int link_elf_lookup_symbol(linker_file_t, const char*, 103 c_linker_sym_t*); 104 static int link_elf_symbol_values(linker_file_t, c_linker_sym_t, linker_symval_t*); 105 static int link_elf_search_symbol(linker_file_t, caddr_t value, 106 c_linker_sym_t* sym, long* diffp); 107 108 static void link_elf_unload_file(linker_file_t); 109 static void link_elf_unload_preload(linker_file_t); 110 111 static kobj_method_t link_elf_methods[] = { 112 KOBJMETHOD(linker_lookup_symbol, link_elf_lookup_symbol), 113 KOBJMETHOD(linker_symbol_values, link_elf_symbol_values), 114 KOBJMETHOD(linker_search_symbol, link_elf_search_symbol), 115 KOBJMETHOD(linker_unload, link_elf_unload_file), 116 KOBJMETHOD(linker_load_file, link_elf_load_file), 117 KOBJMETHOD(linker_link_preload, link_elf_link_preload), 118 KOBJMETHOD(linker_link_preload_finish, link_elf_link_preload_finish), 119 { 0, 0 } 120 }; 121 122 static struct linker_class link_elf_class = { 123 #if ELF_TARG_CLASS == ELFCLASS32 124 "elf32", 125 #else 126 "elf64", 127 #endif 128 link_elf_methods, sizeof(struct elf_file) 129 }; 130 131 static int parse_dynamic(elf_file_t ef); 132 static int relocate_file(elf_file_t ef); 133 static int link_elf_preload_parse_symbols(elf_file_t ef); 134 135 #ifdef DDB 136 static void r_debug_state(struct r_debug *dummy_one, 137 struct link_map *dummy_two); 138 139 /* 140 * A list of loaded modules for GDB to use for loading symbols. 141 */ 142 struct r_debug r_debug; 143 144 #define GDB_STATE(s) r_debug.r_state = s; r_debug_state(NULL, NULL); 145 146 /* 147 * Function for the debugger to set a breakpoint on to gain control. 148 */ 149 void 150 r_debug_state(struct r_debug *dummy_one __unused, 151 struct link_map *dummy_two __unused) 152 { 153 } 154 155 #endif 156 157 /* 158 * The kernel symbol table starts here. 159 */ 160 #ifndef __ia64__ 161 extern struct _dynamic _DYNAMIC; 162 #endif 163 164 static void 165 link_elf_init(void* arg) 166 { 167 #ifdef __ELF__ 168 Elf_Dyn *dp; 169 caddr_t modptr, baseptr, sizeptr; 170 elf_file_t ef; 171 char *modname; 172 #endif 173 174 linker_add_class(&link_elf_class); 175 176 #ifdef __ELF__ 177 #ifndef __ia64__ 178 dp = (Elf_Dyn*) &_DYNAMIC; 179 #else 180 dp = 0; 181 #endif 182 if (dp) { 183 modname = NULL; 184 modptr = preload_search_by_type("elf kernel"); 185 if (modptr) 186 modname = (char *)preload_search_info(modptr, MODINFO_NAME); 187 if (modname == NULL) 188 modname = "kernel"; 189 linker_kernel_file = linker_make_file(modname, &link_elf_class); 190 if (linker_kernel_file == NULL) 191 panic("link_elf_init: Can't create linker structures for kernel"); 192 193 ef = (elf_file_t) linker_kernel_file; 194 ef->preloaded = 1; 195 ef->address = 0; 196 #ifdef SPARSE_MAPPING 197 ef->object = 0; 198 #endif 199 ef->dynamic = dp; 200 201 parse_dynamic(ef); 202 linker_kernel_file->address = (caddr_t) KERNBASE; 203 linker_kernel_file->size = -(intptr_t)linker_kernel_file->address; 204 205 if (modptr) { 206 ef->modptr = modptr; 207 baseptr = preload_search_info(modptr, MODINFO_ADDR); 208 if (baseptr) 209 linker_kernel_file->address = *(caddr_t *)baseptr; 210 sizeptr = preload_search_info(modptr, MODINFO_SIZE); 211 if (sizeptr) 212 linker_kernel_file->size = *(size_t *)sizeptr; 213 } 214 (void)link_elf_preload_parse_symbols(ef); 215 216 #ifdef DDB 217 ef->gdb.l_addr = linker_kernel_file->address; 218 ef->gdb.l_name = modname; 219 ef->gdb.l_ld = dp; 220 ef->gdb.l_prev = 0; 221 ef->gdb.l_next = 0; 222 223 r_debug.r_map = &ef->gdb; 224 r_debug.r_brk = r_debug_state; 225 r_debug.r_state = RT_CONSISTENT; 226 227 r_debug_state(NULL, NULL); /* say hello to gdb! */ 228 #endif 229 230 } 231 #endif 232 } 233 234 SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_SECOND, link_elf_init, 0); 235 236 static int 237 link_elf_preload_parse_symbols(elf_file_t ef) 238 { 239 caddr_t pointer; 240 caddr_t ssym, esym, base; 241 caddr_t strtab; 242 int strcnt; 243 Elf_Sym* symtab; 244 int symcnt; 245 246 if (ef->modptr == NULL) 247 return 0; 248 pointer = preload_search_info(ef->modptr, MODINFO_METADATA|MODINFOMD_SSYM); 249 if (pointer == NULL) 250 return 0; 251 ssym = *(caddr_t *)pointer; 252 pointer = preload_search_info(ef->modptr, MODINFO_METADATA|MODINFOMD_ESYM); 253 if (pointer == NULL) 254 return 0; 255 esym = *(caddr_t *)pointer; 256 257 base = ssym; 258 259 symcnt = *(long *)base; 260 base += sizeof(long); 261 symtab = (Elf_Sym *)base; 262 base += roundup(symcnt, sizeof(long)); 263 264 if (base > esym || base < ssym) { 265 printf("Symbols are corrupt!\n"); 266 return EINVAL; 267 } 268 269 strcnt = *(long *)base; 270 base += sizeof(long); 271 strtab = base; 272 base += roundup(strcnt, sizeof(long)); 273 274 if (base > esym || base < ssym) { 275 printf("Symbols are corrupt!\n"); 276 return EINVAL; 277 } 278 279 ef->ddbsymtab = symtab; 280 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym); 281 ef->ddbstrtab = strtab; 282 ef->ddbstrcnt = strcnt; 283 284 return 0; 285 } 286 287 static int 288 parse_dynamic(elf_file_t ef) 289 { 290 Elf_Dyn *dp; 291 int plttype = DT_REL; 292 293 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) { 294 switch (dp->d_tag) { 295 case DT_HASH: 296 { 297 /* From src/libexec/rtld-elf/rtld.c */ 298 const Elf_Off *hashtab = (const Elf_Off *) 299 (ef->address + dp->d_un.d_ptr); 300 ef->nbuckets = hashtab[0]; 301 ef->nchains = hashtab[1]; 302 ef->buckets = hashtab + 2; 303 ef->chains = ef->buckets + ef->nbuckets; 304 break; 305 } 306 case DT_STRTAB: 307 ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr); 308 break; 309 case DT_STRSZ: 310 ef->strsz = dp->d_un.d_val; 311 break; 312 case DT_SYMTAB: 313 ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr); 314 break; 315 case DT_SYMENT: 316 if (dp->d_un.d_val != sizeof(Elf_Sym)) 317 return ENOEXEC; 318 break; 319 case DT_PLTGOT: 320 ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr); 321 break; 322 case DT_REL: 323 ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr); 324 break; 325 case DT_RELSZ: 326 ef->relsize = dp->d_un.d_val; 327 break; 328 case DT_RELENT: 329 if (dp->d_un.d_val != sizeof(Elf_Rel)) 330 return ENOEXEC; 331 break; 332 case DT_JMPREL: 333 ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr); 334 break; 335 case DT_PLTRELSZ: 336 ef->pltrelsize = dp->d_un.d_val; 337 break; 338 case DT_RELA: 339 ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr); 340 break; 341 case DT_RELASZ: 342 ef->relasize = dp->d_un.d_val; 343 break; 344 case DT_RELAENT: 345 if (dp->d_un.d_val != sizeof(Elf_Rela)) 346 return ENOEXEC; 347 break; 348 case DT_PLTREL: 349 plttype = dp->d_un.d_val; 350 if (plttype != DT_REL && plttype != DT_RELA) 351 return ENOEXEC; 352 break; 353 #ifdef DDB 354 case DT_DEBUG: 355 dp->d_un.d_ptr = (Elf_Addr) &r_debug; 356 break; 357 #endif 358 } 359 } 360 361 if (plttype == DT_RELA) { 362 ef->pltrela = (const Elf_Rela *) ef->pltrel; 363 ef->pltrel = NULL; 364 ef->pltrelasize = ef->pltrelsize; 365 ef->pltrelsize = 0; 366 } 367 368 ef->ddbsymtab = ef->symtab; 369 ef->ddbsymcnt = ef->nchains; 370 ef->ddbstrtab = ef->strtab; 371 ef->ddbstrcnt = ef->strsz; 372 373 return 0; 374 } 375 376 static void 377 link_elf_error(const char *s) 378 { 379 printf("kldload: %s\n", s); 380 } 381 382 #ifdef DDB 383 384 static void 385 link_elf_add_gdb(struct link_map *l) 386 { 387 struct link_map *prev; 388 389 /* 390 * Scan to the end of the list. 391 */ 392 for (prev = r_debug.r_map; prev->l_next != NULL; prev = prev->l_next) 393 ; 394 395 /* Link in the new entry. */ 396 l->l_prev = prev; 397 l->l_next = prev->l_next; 398 prev->l_next = l; 399 } 400 401 static void 402 link_elf_delete_gdb(struct link_map *l) 403 { 404 if (l->l_prev == NULL) { 405 if ((r_debug.r_map = l->l_next) != NULL) 406 l->l_next->l_prev = NULL; 407 return; 408 } 409 410 if ((l->l_prev->l_next = l->l_next) != NULL) 411 l->l_next->l_prev = l->l_prev; 412 } 413 414 #endif /* DDB */ 415 416 static int 417 link_elf_link_preload(linker_class_t cls, 418 const char* filename, linker_file_t *result) 419 { 420 caddr_t modptr, baseptr, sizeptr, dynptr; 421 char *type; 422 elf_file_t ef; 423 linker_file_t lf; 424 int error; 425 vm_offset_t dp; 426 427 /* Look to see if we have the file preloaded */ 428 modptr = preload_search_by_name(filename); 429 if (modptr == NULL) 430 return ENOENT; 431 432 type = (char *)preload_search_info(modptr, MODINFO_TYPE); 433 baseptr = preload_search_info(modptr, MODINFO_ADDR); 434 sizeptr = preload_search_info(modptr, MODINFO_SIZE); 435 dynptr = preload_search_info(modptr, MODINFO_METADATA|MODINFOMD_DYNAMIC); 436 if (type == NULL || strcmp(type, "elf module") != 0) 437 return (EFTYPE); 438 if (baseptr == NULL || sizeptr == NULL || dynptr == NULL) 439 return (EINVAL); 440 441 lf = linker_make_file(filename, &link_elf_class); 442 if (lf == NULL) { 443 return ENOMEM; 444 } 445 446 ef = (elf_file_t) lf; 447 ef->preloaded = 1; 448 ef->modptr = modptr; 449 ef->address = *(caddr_t *)baseptr; 450 #ifdef SPARSE_MAPPING 451 ef->object = 0; 452 #endif 453 dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr; 454 ef->dynamic = (Elf_Dyn *)dp; 455 lf->address = ef->address; 456 lf->size = *(size_t *)sizeptr; 457 458 error = parse_dynamic(ef); 459 if (error) { 460 linker_file_unload(lf); 461 return error; 462 } 463 *result = lf; 464 return (0); 465 } 466 467 static int 468 link_elf_link_preload_finish(linker_file_t lf) 469 { 470 elf_file_t ef; 471 int error; 472 473 ef = (elf_file_t) lf; 474 #if 0 /* this will be more trouble than it's worth for now */ 475 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) { 476 if (dp->d_tag != DT_NEEDED) 477 continue; 478 modname = ef->strtab + dp->d_un.d_val; 479 error = linker_load_module(modname, lf); 480 if (error) 481 goto out; 482 } 483 #endif 484 error = relocate_file(ef); 485 if (error) 486 return error; 487 (void)link_elf_preload_parse_symbols(ef); 488 489 #ifdef DDB 490 GDB_STATE(RT_ADD); 491 ef->gdb.l_addr = lf->address; 492 ef->gdb.l_name = lf->filename; 493 ef->gdb.l_ld = ef->dynamic; 494 link_elf_add_gdb(&ef->gdb); 495 GDB_STATE(RT_CONSISTENT); 496 #endif 497 498 return (0); 499 } 500 501 static int 502 link_elf_load_file(linker_class_t cls, const char* filename, linker_file_t* result) 503 { 504 struct nameidata nd; 505 struct proc* p = curproc; /* XXX */ 506 Elf_Ehdr *hdr; 507 caddr_t firstpage; 508 int nbytes, i; 509 Elf_Phdr *phdr; 510 Elf_Phdr *phlimit; 511 Elf_Phdr *segs[2]; 512 int nsegs; 513 Elf_Phdr *phdyn; 514 Elf_Phdr *phphdr; 515 caddr_t mapbase; 516 size_t mapsize; 517 Elf_Off base_offset; 518 Elf_Addr base_vaddr; 519 Elf_Addr base_vlimit; 520 int error = 0; 521 int resid, flags; 522 elf_file_t ef; 523 linker_file_t lf; 524 Elf_Shdr *shdr; 525 int symtabindex; 526 int symstrindex; 527 int symcnt; 528 int strcnt; 529 530 shdr = NULL; 531 lf = NULL; 532 533 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, p); 534 flags = FREAD; 535 error = vn_open(&nd, &flags, 0); 536 if (error) 537 return error; 538 NDFREE(&nd, NDF_ONLY_PNBUF); 539 540 /* 541 * Read the elf header from the file. 542 */ 543 firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK); 544 if (firstpage == NULL) { 545 error = ENOMEM; 546 goto out; 547 } 548 hdr = (Elf_Ehdr *)firstpage; 549 error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0, 550 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, p); 551 nbytes = PAGE_SIZE - resid; 552 if (error) 553 goto out; 554 555 if (!IS_ELF(*hdr)) { 556 error = ENOEXEC; 557 goto out; 558 } 559 560 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS 561 || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) { 562 link_elf_error("Unsupported file layout"); 563 error = ENOEXEC; 564 goto out; 565 } 566 if (hdr->e_ident[EI_VERSION] != EV_CURRENT 567 || hdr->e_version != EV_CURRENT) { 568 link_elf_error("Unsupported file version"); 569 error = ENOEXEC; 570 goto out; 571 } 572 if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) { 573 link_elf_error("Unsupported file type"); 574 error = ENOEXEC; 575 goto out; 576 } 577 if (hdr->e_machine != ELF_TARG_MACH) { 578 link_elf_error("Unsupported machine"); 579 error = ENOEXEC; 580 goto out; 581 } 582 583 /* 584 * We rely on the program header being in the first page. This is 585 * not strictly required by the ABI specification, but it seems to 586 * always true in practice. And, it simplifies things considerably. 587 */ 588 if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) && 589 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) && 590 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes))) 591 link_elf_error("Unreadable program headers"); 592 593 /* 594 * Scan the program header entries, and save key information. 595 * 596 * We rely on there being exactly two load segments, text and data, 597 * in that order. 598 */ 599 phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff); 600 phlimit = phdr + hdr->e_phnum; 601 nsegs = 0; 602 phdyn = NULL; 603 phphdr = NULL; 604 while (phdr < phlimit) { 605 switch (phdr->p_type) { 606 607 case PT_LOAD: 608 if (nsegs == 2) { 609 link_elf_error("Too many sections"); 610 error = ENOEXEC; 611 goto out; 612 } 613 segs[nsegs] = phdr; 614 ++nsegs; 615 break; 616 617 case PT_PHDR: 618 phphdr = phdr; 619 break; 620 621 case PT_DYNAMIC: 622 phdyn = phdr; 623 break; 624 625 case PT_INTERP: 626 link_elf_error("Unsupported file type"); 627 error = ENOEXEC; 628 goto out; 629 } 630 631 ++phdr; 632 } 633 if (phdyn == NULL) { 634 link_elf_error("Object is not dynamically-linked"); 635 error = ENOEXEC; 636 goto out; 637 } 638 639 /* 640 * Allocate the entire address space of the object, to stake out our 641 * contiguous region, and to establish the base address for relocation. 642 */ 643 base_offset = trunc_page(segs[0]->p_offset); 644 base_vaddr = trunc_page(segs[0]->p_vaddr); 645 base_vlimit = round_page(segs[1]->p_vaddr + segs[1]->p_memsz); 646 mapsize = base_vlimit - base_vaddr; 647 648 lf = linker_make_file(filename, &link_elf_class); 649 if (!lf) { 650 error = ENOMEM; 651 goto out; 652 } 653 654 ef = (elf_file_t) lf; 655 #ifdef SPARSE_MAPPING 656 mtx_lock(&vm_mtx); 657 ef->object = vm_object_allocate(OBJT_DEFAULT, mapsize >> PAGE_SHIFT); 658 if (ef->object == NULL) { 659 mtx_unlock(&vm_mtx); 660 free(ef, M_LINKER); 661 error = ENOMEM; 662 goto out; 663 } 664 vm_object_reference(ef->object); 665 ef->address = (caddr_t) vm_map_min(kernel_map); 666 error = vm_map_find(kernel_map, ef->object, 0, 667 (vm_offset_t *) &ef->address, 668 mapsize, 1, 669 VM_PROT_ALL, VM_PROT_ALL, 0); 670 if (error) { 671 vm_object_deallocate(ef->object); 672 mtx_unlock(&vm_mtx); 673 ef->object = 0; 674 goto out; 675 } 676 mtx_unlock(&vm_mtx); 677 #else 678 ef->address = malloc(mapsize, M_LINKER, M_WAITOK); 679 if (!ef->address) { 680 error = ENOMEM; 681 goto out; 682 } 683 #endif 684 mapbase = ef->address; 685 686 /* 687 * Read the text and data sections and zero the bss. 688 */ 689 for (i = 0; i < 2; i++) { 690 caddr_t segbase = mapbase + segs[i]->p_vaddr - base_vaddr; 691 error = vn_rdwr(UIO_READ, nd.ni_vp, 692 segbase, segs[i]->p_filesz, segs[i]->p_offset, 693 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, p); 694 if (error) { 695 goto out; 696 } 697 bzero(segbase + segs[i]->p_filesz, 698 segs[i]->p_memsz - segs[i]->p_filesz); 699 700 #ifdef SPARSE_MAPPING 701 /* 702 * Wire down the pages 703 */ 704 mtx_lock(&vm_mtx); 705 vm_map_pageable(kernel_map, 706 (vm_offset_t) segbase, 707 (vm_offset_t) segbase + segs[i]->p_memsz, 708 FALSE); 709 mtx_unlock(&vm_mtx); 710 #endif 711 } 712 713 ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr); 714 715 lf->address = ef->address; 716 lf->size = mapsize; 717 718 error = parse_dynamic(ef); 719 if (error) 720 goto out; 721 error = linker_load_dependancies(lf); 722 if (error) 723 goto out; 724 #if 0 /* this will be more trouble than it's worth for now */ 725 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) { 726 if (dp->d_tag != DT_NEEDED) 727 continue; 728 modname = ef->strtab + dp->d_un.d_val; 729 error = linker_load_module(modname, lf); 730 if (error) 731 goto out; 732 } 733 #endif 734 error = relocate_file(ef); 735 if (error) 736 goto out; 737 738 /* Try and load the symbol table if it's present. (you can strip it!) */ 739 nbytes = hdr->e_shnum * hdr->e_shentsize; 740 if (nbytes == 0 || hdr->e_shoff == 0) 741 goto nosyms; 742 shdr = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO); 743 if (shdr == NULL) { 744 error = ENOMEM; 745 goto out; 746 } 747 error = vn_rdwr(UIO_READ, nd.ni_vp, 748 (caddr_t)shdr, nbytes, hdr->e_shoff, 749 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, p); 750 if (error) 751 goto out; 752 symtabindex = -1; 753 symstrindex = -1; 754 for (i = 0; i < hdr->e_shnum; i++) { 755 if (shdr[i].sh_type == SHT_SYMTAB) { 756 symtabindex = i; 757 symstrindex = shdr[i].sh_link; 758 } 759 } 760 if (symtabindex < 0 || symstrindex < 0) 761 goto nosyms; 762 763 symcnt = shdr[symtabindex].sh_size; 764 ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK); 765 strcnt = shdr[symstrindex].sh_size; 766 ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK); 767 768 if (ef->symbase == NULL || ef->strbase == NULL) { 769 error = ENOMEM; 770 goto out; 771 } 772 error = vn_rdwr(UIO_READ, nd.ni_vp, 773 ef->symbase, symcnt, shdr[symtabindex].sh_offset, 774 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, p); 775 if (error) 776 goto out; 777 error = vn_rdwr(UIO_READ, nd.ni_vp, 778 ef->strbase, strcnt, shdr[symstrindex].sh_offset, 779 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, p); 780 if (error) 781 goto out; 782 783 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym); 784 ef->ddbsymtab = (const Elf_Sym *)ef->symbase; 785 ef->ddbstrcnt = strcnt; 786 ef->ddbstrtab = ef->strbase; 787 788 #ifdef DDB 789 GDB_STATE(RT_ADD); 790 ef->gdb.l_addr = lf->address; 791 ef->gdb.l_name = filename; 792 ef->gdb.l_ld = ef->dynamic; 793 link_elf_add_gdb(&ef->gdb); 794 GDB_STATE(RT_CONSISTENT); 795 #endif 796 797 nosyms: 798 799 *result = lf; 800 801 out: 802 if (error && lf) 803 linker_file_unload(lf); 804 if (shdr) 805 free(shdr, M_LINKER); 806 if (firstpage) 807 free(firstpage, M_LINKER); 808 VOP_UNLOCK(nd.ni_vp, 0, p); 809 vn_close(nd.ni_vp, FREAD, p->p_ucred, p); 810 811 return error; 812 } 813 814 static void 815 link_elf_unload_file(linker_file_t file) 816 { 817 elf_file_t ef = (elf_file_t) file; 818 819 #ifdef DDB 820 if (ef->gdb.l_ld) { 821 GDB_STATE(RT_DELETE); 822 link_elf_delete_gdb(&ef->gdb); 823 GDB_STATE(RT_CONSISTENT); 824 } 825 #endif 826 827 if (ef->preloaded) { 828 link_elf_unload_preload(file); 829 return; 830 } 831 #ifdef SPARSE_MAPPING 832 if (ef->object) { 833 mtx_lock(&vm_mtx); 834 vm_map_remove(kernel_map, (vm_offset_t) ef->address, 835 (vm_offset_t) ef->address 836 + (ef->object->size << PAGE_SHIFT)); 837 vm_object_deallocate(ef->object); 838 mtx_unlock(&vm_mtx); 839 } 840 #else 841 if (ef->address) 842 free(ef->address, M_LINKER); 843 #endif 844 if (ef->symbase) 845 free(ef->symbase, M_LINKER); 846 if (ef->strbase) 847 free(ef->strbase, M_LINKER); 848 } 849 850 static void 851 link_elf_unload_preload(linker_file_t file) 852 { 853 if (file->filename) 854 preload_delete_name(file->filename); 855 } 856 857 static const char * 858 symbol_name(elf_file_t ef, Elf_Word r_info) 859 { 860 const Elf_Sym *ref; 861 862 if (ELF_R_SYM(r_info)) { 863 ref = ef->symtab + ELF_R_SYM(r_info); 864 return ef->strtab + ref->st_name; 865 } else 866 return NULL; 867 } 868 869 static int 870 relocate_file(elf_file_t ef) 871 { 872 const Elf_Rel *rellim; 873 const Elf_Rel *rel; 874 const Elf_Rela *relalim; 875 const Elf_Rela *rela; 876 const char *symname; 877 878 /* Perform relocations without addend if there are any: */ 879 rel = ef->rel; 880 if (rel) { 881 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize); 882 while (rel < rellim) { 883 symname = symbol_name(ef, rel->r_info); 884 if (elf_reloc(&ef->lf, rel, ELF_RELOC_REL, symname)) { 885 printf("link_elf: symbol %s undefined\n", symname); 886 return ENOENT; 887 } 888 rel++; 889 } 890 } 891 892 /* Perform relocations with addend if there are any: */ 893 rela = ef->rela; 894 if (rela) { 895 relalim = (const Elf_Rela *)((const char *)ef->rela + ef->relasize); 896 while (rela < relalim) { 897 symname = symbol_name(ef, rela->r_info); 898 if (elf_reloc(&ef->lf, rela, ELF_RELOC_RELA, symname)) { 899 printf("link_elf: symbol %s undefined\n", symname); 900 return ENOENT; 901 } 902 rela++; 903 } 904 } 905 906 /* Perform PLT relocations without addend if there are any: */ 907 rel = ef->pltrel; 908 if (rel) { 909 rellim = (const Elf_Rel *)((const char *)ef->pltrel + ef->pltrelsize); 910 while (rel < rellim) { 911 symname = symbol_name(ef, rel->r_info); 912 if (elf_reloc(&ef->lf, rel, ELF_RELOC_REL, symname)) { 913 printf("link_elf: symbol %s undefined\n", symname); 914 return ENOENT; 915 } 916 rel++; 917 } 918 } 919 920 /* Perform relocations with addend if there are any: */ 921 rela = ef->pltrela; 922 if (rela) { 923 relalim = (const Elf_Rela *)((const char *)ef->pltrela + ef->pltrelasize); 924 while (rela < relalim) { 925 symname = symbol_name(ef, rela->r_info); 926 if (elf_reloc(&ef->lf, rela, ELF_RELOC_RELA, symname)) { 927 printf("link_elf: symbol %s undefined\n", symname); 928 return ENOENT; 929 } 930 rela++; 931 } 932 } 933 934 return 0; 935 } 936 937 /* 938 * Hash function for symbol table lookup. Don't even think about changing 939 * this. It is specified by the System V ABI. 940 */ 941 static unsigned long 942 elf_hash(const char *name) 943 { 944 const unsigned char *p = (const unsigned char *) name; 945 unsigned long h = 0; 946 unsigned long g; 947 948 while (*p != '\0') { 949 h = (h << 4) + *p++; 950 if ((g = h & 0xf0000000) != 0) 951 h ^= g >> 24; 952 h &= ~g; 953 } 954 return h; 955 } 956 957 int 958 link_elf_lookup_symbol(linker_file_t lf, const char* name, c_linker_sym_t* sym) 959 { 960 elf_file_t ef = (elf_file_t) lf; 961 unsigned long symnum; 962 const Elf_Sym* symp; 963 const char *strp; 964 unsigned long hash; 965 int i; 966 967 /* First, search hashed global symbols */ 968 hash = elf_hash(name); 969 symnum = ef->buckets[hash % ef->nbuckets]; 970 971 while (symnum != STN_UNDEF) { 972 if (symnum >= ef->nchains) { 973 printf("link_elf_lookup_symbol: corrupt symbol table\n"); 974 return ENOENT; 975 } 976 977 symp = ef->symtab + symnum; 978 if (symp->st_name == 0) { 979 printf("link_elf_lookup_symbol: corrupt symbol table\n"); 980 return ENOENT; 981 } 982 983 strp = ef->strtab + symp->st_name; 984 985 if (strcmp(name, strp) == 0) { 986 if (symp->st_shndx != SHN_UNDEF || 987 (symp->st_value != 0 && 988 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) { 989 *sym = (c_linker_sym_t) symp; 990 return 0; 991 } else 992 return ENOENT; 993 } 994 995 symnum = ef->chains[symnum]; 996 } 997 998 /* If we have not found it, look at the full table (if loaded) */ 999 if (ef->symtab == ef->ddbsymtab) 1000 return ENOENT; 1001 1002 /* Exhaustive search */ 1003 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1004 strp = ef->ddbstrtab + symp->st_name; 1005 if (strcmp(name, strp) == 0) { 1006 if (symp->st_shndx != SHN_UNDEF || 1007 (symp->st_value != 0 && 1008 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) { 1009 *sym = (c_linker_sym_t) symp; 1010 return 0; 1011 } else 1012 return ENOENT; 1013 } 1014 } 1015 1016 return ENOENT; 1017 } 1018 1019 static int 1020 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, linker_symval_t* symval) 1021 { 1022 elf_file_t ef = (elf_file_t) lf; 1023 const Elf_Sym* es = (const Elf_Sym*) sym; 1024 1025 if (es >= ef->symtab && ((es - ef->symtab) < ef->nchains)) { 1026 symval->name = ef->strtab + es->st_name; 1027 symval->value = (caddr_t) ef->address + es->st_value; 1028 symval->size = es->st_size; 1029 return 0; 1030 } 1031 if (ef->symtab == ef->ddbsymtab) 1032 return ENOENT; 1033 if (es >= ef->ddbsymtab && ((es - ef->ddbsymtab) < ef->ddbsymcnt)) { 1034 symval->name = ef->ddbstrtab + es->st_name; 1035 symval->value = (caddr_t) ef->address + es->st_value; 1036 symval->size = es->st_size; 1037 return 0; 1038 } 1039 return ENOENT; 1040 } 1041 1042 static int 1043 link_elf_search_symbol(linker_file_t lf, caddr_t value, 1044 c_linker_sym_t* sym, long* diffp) 1045 { 1046 elf_file_t ef = (elf_file_t) lf; 1047 u_long off = (uintptr_t) (void *) value; 1048 u_long diff = off; 1049 u_long st_value; 1050 const Elf_Sym* es; 1051 const Elf_Sym* best = 0; 1052 int i; 1053 1054 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) { 1055 if (es->st_name == 0) 1056 continue; 1057 st_value = es->st_value + (uintptr_t) (void *) ef->address; 1058 if (off >= st_value) { 1059 if (off - st_value < diff) { 1060 diff = off - st_value; 1061 best = es; 1062 if (diff == 0) 1063 break; 1064 } else if (off - st_value == diff) { 1065 best = es; 1066 } 1067 } 1068 } 1069 if (best == 0) 1070 *diffp = off; 1071 else 1072 *diffp = diff; 1073 *sym = (c_linker_sym_t) best; 1074 1075 return 0; 1076 } 1077