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/mutex.h> 37 #include <sys/proc.h> 38 #include <sys/namei.h> 39 #include <sys/fcntl.h> 40 #include <sys/vnode.h> 41 #include <sys/linker.h> 42 43 #include <machine/elf.h> 44 45 #include <vm/vm.h> 46 #include <vm/vm_param.h> 47 #ifdef SPARSE_MAPPING 48 #include <vm/vm_object.h> 49 #include <vm/vm_kern.h> 50 #include <vm/vm_extern.h> 51 #endif 52 #include <vm/pmap.h> 53 #include <vm/vm_map.h> 54 55 #ifdef __AOUT__ 56 #include <nlist.h> 57 #endif 58 #include <link.h> 59 60 #include "linker_if.h" 61 62 typedef struct elf_file { 63 struct linker_file lf; /* Common fields */ 64 int preloaded; /* Was file pre-loaded */ 65 caddr_t address; /* Relocation address */ 66 #ifdef SPARSE_MAPPING 67 vm_object_t object; /* VM object to hold file pages */ 68 #endif 69 Elf_Dyn* dynamic; /* Symbol table etc. */ 70 Elf_Off nbuckets; /* DT_HASH info */ 71 Elf_Off nchains; 72 const Elf_Off* buckets; 73 const Elf_Off* chains; 74 caddr_t hash; 75 caddr_t strtab; /* DT_STRTAB */ 76 int strsz; /* DT_STRSZ */ 77 const Elf_Sym* symtab; /* DT_SYMTAB */ 78 Elf_Addr* got; /* DT_PLTGOT */ 79 const Elf_Rel* pltrel; /* DT_JMPREL */ 80 int pltrelsize; /* DT_PLTRELSZ */ 81 const Elf_Rela* pltrela; /* DT_JMPREL */ 82 int pltrelasize; /* DT_PLTRELSZ */ 83 const Elf_Rel* rel; /* DT_REL */ 84 int relsize; /* DT_RELSZ */ 85 const Elf_Rela* rela; /* DT_RELA */ 86 int relasize; /* DT_RELASZ */ 87 caddr_t modptr; 88 const Elf_Sym* ddbsymtab; /* The symbol table we are using */ 89 long ddbsymcnt; /* Number of symbols */ 90 caddr_t ddbstrtab; /* String table */ 91 long ddbstrcnt; /* number of bytes in string table */ 92 caddr_t symbase; /* malloc'ed symbold base */ 93 caddr_t strbase; /* malloc'ed string base */ 94 #ifdef DDB 95 struct link_map gdb; /* hooks for gdb */ 96 #endif 97 } *elf_file_t; 98 99 static int link_elf_link_preload(linker_class_t cls, 100 const char*, linker_file_t*); 101 static int link_elf_link_preload_finish(linker_file_t); 102 static int link_elf_load_file(linker_class_t, const char*, linker_file_t*); 103 static int link_elf_lookup_symbol(linker_file_t, const char*, 104 c_linker_sym_t*); 105 static int link_elf_symbol_values(linker_file_t, c_linker_sym_t, linker_symval_t*); 106 static int link_elf_search_symbol(linker_file_t, caddr_t value, 107 c_linker_sym_t* sym, long* diffp); 108 109 static void link_elf_unload_file(linker_file_t); 110 static void link_elf_unload_preload(linker_file_t); 111 static int link_elf_lookup_set(linker_file_t, const char *, 112 void ***, void ***, int *); 113 114 static kobj_method_t link_elf_methods[] = { 115 KOBJMETHOD(linker_lookup_symbol, link_elf_lookup_symbol), 116 KOBJMETHOD(linker_symbol_values, link_elf_symbol_values), 117 KOBJMETHOD(linker_search_symbol, link_elf_search_symbol), 118 KOBJMETHOD(linker_unload, link_elf_unload_file), 119 KOBJMETHOD(linker_load_file, link_elf_load_file), 120 KOBJMETHOD(linker_link_preload, link_elf_link_preload), 121 KOBJMETHOD(linker_link_preload_finish, link_elf_link_preload_finish), 122 KOBJMETHOD(linker_lookup_set, link_elf_lookup_set), 123 { 0, 0 } 124 }; 125 126 static struct linker_class link_elf_class = { 127 #if ELF_TARG_CLASS == ELFCLASS32 128 "elf32", 129 #else 130 "elf64", 131 #endif 132 link_elf_methods, sizeof(struct elf_file) 133 }; 134 135 static int parse_dynamic(elf_file_t ef); 136 static int relocate_file(elf_file_t ef); 137 static int link_elf_preload_parse_symbols(elf_file_t ef); 138 139 #ifdef DDB 140 static void r_debug_state(struct r_debug *dummy_one, 141 struct link_map *dummy_two); 142 143 /* 144 * A list of loaded modules for GDB to use for loading symbols. 145 */ 146 struct r_debug r_debug; 147 148 #define GDB_STATE(s) r_debug.r_state = s; r_debug_state(NULL, NULL); 149 150 /* 151 * Function for the debugger to set a breakpoint on to gain control. 152 */ 153 void 154 r_debug_state(struct r_debug *dummy_one __unused, 155 struct link_map *dummy_two __unused) 156 { 157 } 158 159 #endif 160 161 /* 162 * The kernel symbol table starts here. 163 */ 164 #ifndef __ia64__ 165 extern struct _dynamic _DYNAMIC; 166 #endif 167 168 static void 169 link_elf_init(void* arg) 170 { 171 #ifdef __ELF__ 172 Elf_Dyn *dp; 173 caddr_t modptr, baseptr, sizeptr; 174 elf_file_t ef; 175 char *modname; 176 #endif 177 178 linker_add_class(&link_elf_class); 179 180 #ifdef __ELF__ 181 #ifndef __ia64__ 182 dp = (Elf_Dyn*) &_DYNAMIC; 183 #else 184 dp = 0; 185 #endif 186 if (dp) { 187 modname = NULL; 188 modptr = preload_search_by_type("elf kernel"); 189 if (modptr) 190 modname = (char *)preload_search_info(modptr, MODINFO_NAME); 191 if (modname == NULL) 192 modname = "kernel"; 193 linker_kernel_file = linker_make_file(modname, &link_elf_class); 194 if (linker_kernel_file == NULL) 195 panic("link_elf_init: Can't create linker structures for kernel"); 196 197 ef = (elf_file_t) linker_kernel_file; 198 ef->preloaded = 1; 199 ef->address = 0; 200 #ifdef SPARSE_MAPPING 201 ef->object = 0; 202 #endif 203 ef->dynamic = dp; 204 205 parse_dynamic(ef); 206 linker_kernel_file->address = (caddr_t) KERNBASE; 207 linker_kernel_file->size = -(intptr_t)linker_kernel_file->address; 208 209 if (modptr) { 210 ef->modptr = modptr; 211 baseptr = preload_search_info(modptr, MODINFO_ADDR); 212 if (baseptr) 213 linker_kernel_file->address = *(caddr_t *)baseptr; 214 sizeptr = preload_search_info(modptr, MODINFO_SIZE); 215 if (sizeptr) 216 linker_kernel_file->size = *(size_t *)sizeptr; 217 } 218 (void)link_elf_preload_parse_symbols(ef); 219 220 #ifdef DDB 221 ef->gdb.l_addr = linker_kernel_file->address; 222 ef->gdb.l_name = modname; 223 ef->gdb.l_ld = dp; 224 ef->gdb.l_prev = 0; 225 ef->gdb.l_next = 0; 226 227 r_debug.r_map = &ef->gdb; 228 r_debug.r_brk = r_debug_state; 229 r_debug.r_state = RT_CONSISTENT; 230 231 r_debug_state(NULL, NULL); /* say hello to gdb! */ 232 #endif 233 234 } 235 #endif 236 } 237 238 SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_SECOND, link_elf_init, 0); 239 240 static int 241 link_elf_preload_parse_symbols(elf_file_t ef) 242 { 243 caddr_t pointer; 244 caddr_t ssym, esym, base; 245 caddr_t strtab; 246 int strcnt; 247 Elf_Sym* symtab; 248 int symcnt; 249 250 if (ef->modptr == NULL) 251 return 0; 252 pointer = preload_search_info(ef->modptr, MODINFO_METADATA|MODINFOMD_SSYM); 253 if (pointer == NULL) 254 return 0; 255 ssym = *(caddr_t *)pointer; 256 pointer = preload_search_info(ef->modptr, MODINFO_METADATA|MODINFOMD_ESYM); 257 if (pointer == NULL) 258 return 0; 259 esym = *(caddr_t *)pointer; 260 261 base = ssym; 262 263 symcnt = *(long *)base; 264 base += sizeof(long); 265 symtab = (Elf_Sym *)base; 266 base += roundup(symcnt, sizeof(long)); 267 268 if (base > esym || base < ssym) { 269 printf("Symbols are corrupt!\n"); 270 return EINVAL; 271 } 272 273 strcnt = *(long *)base; 274 base += sizeof(long); 275 strtab = base; 276 base += roundup(strcnt, sizeof(long)); 277 278 if (base > esym || base < ssym) { 279 printf("Symbols are corrupt!\n"); 280 return EINVAL; 281 } 282 283 ef->ddbsymtab = symtab; 284 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym); 285 ef->ddbstrtab = strtab; 286 ef->ddbstrcnt = strcnt; 287 288 return 0; 289 } 290 291 static int 292 parse_dynamic(elf_file_t ef) 293 { 294 Elf_Dyn *dp; 295 int plttype = DT_REL; 296 297 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) { 298 switch (dp->d_tag) { 299 case DT_HASH: 300 { 301 /* From src/libexec/rtld-elf/rtld.c */ 302 const Elf_Off *hashtab = (const Elf_Off *) 303 (ef->address + dp->d_un.d_ptr); 304 ef->nbuckets = hashtab[0]; 305 ef->nchains = hashtab[1]; 306 ef->buckets = hashtab + 2; 307 ef->chains = ef->buckets + ef->nbuckets; 308 break; 309 } 310 case DT_STRTAB: 311 ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr); 312 break; 313 case DT_STRSZ: 314 ef->strsz = dp->d_un.d_val; 315 break; 316 case DT_SYMTAB: 317 ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr); 318 break; 319 case DT_SYMENT: 320 if (dp->d_un.d_val != sizeof(Elf_Sym)) 321 return ENOEXEC; 322 break; 323 case DT_PLTGOT: 324 ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr); 325 break; 326 case DT_REL: 327 ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr); 328 break; 329 case DT_RELSZ: 330 ef->relsize = dp->d_un.d_val; 331 break; 332 case DT_RELENT: 333 if (dp->d_un.d_val != sizeof(Elf_Rel)) 334 return ENOEXEC; 335 break; 336 case DT_JMPREL: 337 ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr); 338 break; 339 case DT_PLTRELSZ: 340 ef->pltrelsize = dp->d_un.d_val; 341 break; 342 case DT_RELA: 343 ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr); 344 break; 345 case DT_RELASZ: 346 ef->relasize = dp->d_un.d_val; 347 break; 348 case DT_RELAENT: 349 if (dp->d_un.d_val != sizeof(Elf_Rela)) 350 return ENOEXEC; 351 break; 352 case DT_PLTREL: 353 plttype = dp->d_un.d_val; 354 if (plttype != DT_REL && plttype != DT_RELA) 355 return ENOEXEC; 356 break; 357 #ifdef DDB 358 case DT_DEBUG: 359 dp->d_un.d_ptr = (Elf_Addr) &r_debug; 360 break; 361 #endif 362 } 363 } 364 365 if (plttype == DT_RELA) { 366 ef->pltrela = (const Elf_Rela *) ef->pltrel; 367 ef->pltrel = NULL; 368 ef->pltrelasize = ef->pltrelsize; 369 ef->pltrelsize = 0; 370 } 371 372 ef->ddbsymtab = ef->symtab; 373 ef->ddbsymcnt = ef->nchains; 374 ef->ddbstrtab = ef->strtab; 375 ef->ddbstrcnt = ef->strsz; 376 377 return 0; 378 } 379 380 static void 381 link_elf_error(const char *s) 382 { 383 printf("kldload: %s\n", s); 384 } 385 386 #ifdef DDB 387 388 static void 389 link_elf_add_gdb(struct link_map *l) 390 { 391 struct link_map *prev; 392 393 /* 394 * Scan to the end of the list. 395 */ 396 for (prev = r_debug.r_map; prev->l_next != NULL; prev = prev->l_next) 397 ; 398 399 /* Link in the new entry. */ 400 l->l_prev = prev; 401 l->l_next = prev->l_next; 402 prev->l_next = l; 403 } 404 405 static void 406 link_elf_delete_gdb(struct link_map *l) 407 { 408 if (l->l_prev == NULL) { 409 if ((r_debug.r_map = l->l_next) != NULL) 410 l->l_next->l_prev = NULL; 411 return; 412 } 413 414 if ((l->l_prev->l_next = l->l_next) != NULL) 415 l->l_next->l_prev = l->l_prev; 416 } 417 418 #endif /* DDB */ 419 420 static int 421 link_elf_link_preload(linker_class_t cls, 422 const char* filename, linker_file_t *result) 423 { 424 caddr_t modptr, baseptr, sizeptr, dynptr; 425 char *type; 426 elf_file_t ef; 427 linker_file_t lf; 428 int error; 429 vm_offset_t dp; 430 431 /* Look to see if we have the file preloaded */ 432 modptr = preload_search_by_name(filename); 433 if (modptr == NULL) 434 return ENOENT; 435 436 type = (char *)preload_search_info(modptr, MODINFO_TYPE); 437 baseptr = preload_search_info(modptr, MODINFO_ADDR); 438 sizeptr = preload_search_info(modptr, MODINFO_SIZE); 439 dynptr = preload_search_info(modptr, MODINFO_METADATA|MODINFOMD_DYNAMIC); 440 if (type == NULL || strcmp(type, "elf module") != 0) 441 return (EFTYPE); 442 if (baseptr == NULL || sizeptr == NULL || dynptr == NULL) 443 return (EINVAL); 444 445 lf = linker_make_file(filename, &link_elf_class); 446 if (lf == NULL) { 447 return ENOMEM; 448 } 449 450 ef = (elf_file_t) lf; 451 ef->preloaded = 1; 452 ef->modptr = modptr; 453 ef->address = *(caddr_t *)baseptr; 454 #ifdef SPARSE_MAPPING 455 ef->object = 0; 456 #endif 457 dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr; 458 ef->dynamic = (Elf_Dyn *)dp; 459 lf->address = ef->address; 460 lf->size = *(size_t *)sizeptr; 461 462 error = parse_dynamic(ef); 463 if (error) { 464 linker_file_unload(lf); 465 return error; 466 } 467 *result = lf; 468 return (0); 469 } 470 471 static int 472 link_elf_link_preload_finish(linker_file_t lf) 473 { 474 elf_file_t ef; 475 int error; 476 477 ef = (elf_file_t) lf; 478 #if 0 /* this will be more trouble than it's worth for now */ 479 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) { 480 if (dp->d_tag != DT_NEEDED) 481 continue; 482 modname = ef->strtab + dp->d_un.d_val; 483 error = linker_load_module(modname, lf); 484 if (error) 485 goto out; 486 } 487 #endif 488 error = relocate_file(ef); 489 if (error) 490 return error; 491 (void)link_elf_preload_parse_symbols(ef); 492 493 #ifdef DDB 494 GDB_STATE(RT_ADD); 495 ef->gdb.l_addr = lf->address; 496 ef->gdb.l_name = lf->filename; 497 ef->gdb.l_ld = ef->dynamic; 498 link_elf_add_gdb(&ef->gdb); 499 GDB_STATE(RT_CONSISTENT); 500 #endif 501 502 return (0); 503 } 504 505 static int 506 link_elf_load_file(linker_class_t cls, const char* filename, linker_file_t* result) 507 { 508 struct nameidata nd; 509 struct proc* p = curproc; /* XXX */ 510 Elf_Ehdr *hdr; 511 caddr_t firstpage; 512 int nbytes, i; 513 Elf_Phdr *phdr; 514 Elf_Phdr *phlimit; 515 Elf_Phdr *segs[2]; 516 int nsegs; 517 Elf_Phdr *phdyn; 518 Elf_Phdr *phphdr; 519 caddr_t mapbase; 520 size_t mapsize; 521 Elf_Off base_offset; 522 Elf_Addr base_vaddr; 523 Elf_Addr base_vlimit; 524 int error = 0; 525 int resid, flags; 526 elf_file_t ef; 527 linker_file_t lf; 528 Elf_Shdr *shdr; 529 int symtabindex; 530 int symstrindex; 531 int symcnt; 532 int strcnt; 533 534 shdr = NULL; 535 lf = NULL; 536 537 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, p); 538 flags = FREAD; 539 error = vn_open(&nd, &flags, 0); 540 if (error) 541 return error; 542 NDFREE(&nd, NDF_ONLY_PNBUF); 543 544 /* 545 * Read the elf header from the file. 546 */ 547 firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK); 548 if (firstpage == NULL) { 549 error = ENOMEM; 550 goto out; 551 } 552 hdr = (Elf_Ehdr *)firstpage; 553 error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0, 554 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, p); 555 nbytes = PAGE_SIZE - resid; 556 if (error) 557 goto out; 558 559 if (!IS_ELF(*hdr)) { 560 error = ENOEXEC; 561 goto out; 562 } 563 564 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS 565 || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) { 566 link_elf_error("Unsupported file layout"); 567 error = ENOEXEC; 568 goto out; 569 } 570 if (hdr->e_ident[EI_VERSION] != EV_CURRENT 571 || hdr->e_version != EV_CURRENT) { 572 link_elf_error("Unsupported file version"); 573 error = ENOEXEC; 574 goto out; 575 } 576 if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) { 577 link_elf_error("Unsupported file type"); 578 error = ENOEXEC; 579 goto out; 580 } 581 if (hdr->e_machine != ELF_TARG_MACH) { 582 link_elf_error("Unsupported machine"); 583 error = ENOEXEC; 584 goto out; 585 } 586 587 /* 588 * We rely on the program header being in the first page. This is 589 * not strictly required by the ABI specification, but it seems to 590 * always true in practice. And, it simplifies things considerably. 591 */ 592 if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) && 593 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) && 594 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes))) 595 link_elf_error("Unreadable program headers"); 596 597 /* 598 * Scan the program header entries, and save key information. 599 * 600 * We rely on there being exactly two load segments, text and data, 601 * in that order. 602 */ 603 phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff); 604 phlimit = phdr + hdr->e_phnum; 605 nsegs = 0; 606 phdyn = NULL; 607 phphdr = NULL; 608 while (phdr < phlimit) { 609 switch (phdr->p_type) { 610 611 case PT_LOAD: 612 if (nsegs == 2) { 613 link_elf_error("Too many sections"); 614 error = ENOEXEC; 615 goto out; 616 } 617 segs[nsegs] = phdr; 618 ++nsegs; 619 break; 620 621 case PT_PHDR: 622 phphdr = phdr; 623 break; 624 625 case PT_DYNAMIC: 626 phdyn = phdr; 627 break; 628 629 case PT_INTERP: 630 link_elf_error("Unsupported file type"); 631 error = ENOEXEC; 632 goto out; 633 } 634 635 ++phdr; 636 } 637 if (phdyn == NULL) { 638 link_elf_error("Object is not dynamically-linked"); 639 error = ENOEXEC; 640 goto out; 641 } 642 643 /* 644 * Allocate the entire address space of the object, to stake out our 645 * contiguous region, and to establish the base address for relocation. 646 */ 647 base_offset = trunc_page(segs[0]->p_offset); 648 base_vaddr = trunc_page(segs[0]->p_vaddr); 649 base_vlimit = round_page(segs[1]->p_vaddr + segs[1]->p_memsz); 650 mapsize = base_vlimit - base_vaddr; 651 652 lf = linker_make_file(filename, &link_elf_class); 653 if (!lf) { 654 error = ENOMEM; 655 goto out; 656 } 657 658 ef = (elf_file_t) lf; 659 #ifdef SPARSE_MAPPING 660 mtx_lock(&vm_mtx); 661 ef->object = vm_object_allocate(OBJT_DEFAULT, mapsize >> PAGE_SHIFT); 662 if (ef->object == NULL) { 663 mtx_unlock(&vm_mtx); 664 free(ef, M_LINKER); 665 error = ENOMEM; 666 goto out; 667 } 668 vm_object_reference(ef->object); 669 ef->address = (caddr_t) vm_map_min(kernel_map); 670 error = vm_map_find(kernel_map, ef->object, 0, 671 (vm_offset_t *) &ef->address, 672 mapsize, 1, 673 VM_PROT_ALL, VM_PROT_ALL, 0); 674 if (error) { 675 vm_object_deallocate(ef->object); 676 mtx_unlock(&vm_mtx); 677 ef->object = 0; 678 goto out; 679 } 680 mtx_unlock(&vm_mtx); 681 #else 682 ef->address = malloc(mapsize, M_LINKER, M_WAITOK); 683 if (!ef->address) { 684 error = ENOMEM; 685 goto out; 686 } 687 #endif 688 mapbase = ef->address; 689 690 /* 691 * Read the text and data sections and zero the bss. 692 */ 693 for (i = 0; i < 2; i++) { 694 caddr_t segbase = mapbase + segs[i]->p_vaddr - base_vaddr; 695 error = vn_rdwr(UIO_READ, nd.ni_vp, 696 segbase, segs[i]->p_filesz, segs[i]->p_offset, 697 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, p); 698 if (error) { 699 goto out; 700 } 701 bzero(segbase + segs[i]->p_filesz, 702 segs[i]->p_memsz - segs[i]->p_filesz); 703 704 #ifdef SPARSE_MAPPING 705 /* 706 * Wire down the pages 707 */ 708 mtx_lock(&vm_mtx); 709 vm_map_pageable(kernel_map, 710 (vm_offset_t) segbase, 711 (vm_offset_t) segbase + segs[i]->p_memsz, 712 FALSE); 713 mtx_unlock(&vm_mtx); 714 #endif 715 } 716 717 ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr); 718 719 lf->address = ef->address; 720 lf->size = mapsize; 721 722 error = parse_dynamic(ef); 723 if (error) 724 goto out; 725 error = linker_load_dependancies(lf); 726 if (error) 727 goto out; 728 #if 0 /* this will be more trouble than it's worth for now */ 729 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) { 730 if (dp->d_tag != DT_NEEDED) 731 continue; 732 modname = ef->strtab + dp->d_un.d_val; 733 error = linker_load_module(modname, lf); 734 if (error) 735 goto out; 736 } 737 #endif 738 error = relocate_file(ef); 739 if (error) 740 goto out; 741 742 /* Try and load the symbol table if it's present. (you can strip it!) */ 743 nbytes = hdr->e_shnum * hdr->e_shentsize; 744 if (nbytes == 0 || hdr->e_shoff == 0) 745 goto nosyms; 746 shdr = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO); 747 if (shdr == NULL) { 748 error = ENOMEM; 749 goto out; 750 } 751 error = vn_rdwr(UIO_READ, nd.ni_vp, 752 (caddr_t)shdr, nbytes, hdr->e_shoff, 753 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, p); 754 if (error) 755 goto out; 756 symtabindex = -1; 757 symstrindex = -1; 758 for (i = 0; i < hdr->e_shnum; i++) { 759 if (shdr[i].sh_type == SHT_SYMTAB) { 760 symtabindex = i; 761 symstrindex = shdr[i].sh_link; 762 } 763 } 764 if (symtabindex < 0 || symstrindex < 0) 765 goto nosyms; 766 767 symcnt = shdr[symtabindex].sh_size; 768 ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK); 769 strcnt = shdr[symstrindex].sh_size; 770 ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK); 771 772 if (ef->symbase == NULL || ef->strbase == NULL) { 773 error = ENOMEM; 774 goto out; 775 } 776 error = vn_rdwr(UIO_READ, nd.ni_vp, 777 ef->symbase, symcnt, shdr[symtabindex].sh_offset, 778 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, p); 779 if (error) 780 goto out; 781 error = vn_rdwr(UIO_READ, nd.ni_vp, 782 ef->strbase, strcnt, shdr[symstrindex].sh_offset, 783 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, p); 784 if (error) 785 goto out; 786 787 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym); 788 ef->ddbsymtab = (const Elf_Sym *)ef->symbase; 789 ef->ddbstrcnt = strcnt; 790 ef->ddbstrtab = ef->strbase; 791 792 #ifdef DDB 793 GDB_STATE(RT_ADD); 794 ef->gdb.l_addr = lf->address; 795 ef->gdb.l_name = filename; 796 ef->gdb.l_ld = ef->dynamic; 797 link_elf_add_gdb(&ef->gdb); 798 GDB_STATE(RT_CONSISTENT); 799 #endif 800 801 nosyms: 802 803 *result = lf; 804 805 out: 806 if (error && lf) 807 linker_file_unload(lf); 808 if (shdr) 809 free(shdr, M_LINKER); 810 if (firstpage) 811 free(firstpage, M_LINKER); 812 VOP_UNLOCK(nd.ni_vp, 0, p); 813 vn_close(nd.ni_vp, FREAD, p->p_ucred, p); 814 815 return error; 816 } 817 818 static void 819 link_elf_unload_file(linker_file_t file) 820 { 821 elf_file_t ef = (elf_file_t) file; 822 823 #ifdef DDB 824 if (ef->gdb.l_ld) { 825 GDB_STATE(RT_DELETE); 826 link_elf_delete_gdb(&ef->gdb); 827 GDB_STATE(RT_CONSISTENT); 828 } 829 #endif 830 831 if (ef->preloaded) { 832 link_elf_unload_preload(file); 833 return; 834 } 835 #ifdef SPARSE_MAPPING 836 if (ef->object) { 837 mtx_lock(&vm_mtx); 838 vm_map_remove(kernel_map, (vm_offset_t) ef->address, 839 (vm_offset_t) ef->address 840 + (ef->object->size << PAGE_SHIFT)); 841 vm_object_deallocate(ef->object); 842 mtx_unlock(&vm_mtx); 843 } 844 #else 845 if (ef->address) 846 free(ef->address, M_LINKER); 847 #endif 848 if (ef->symbase) 849 free(ef->symbase, M_LINKER); 850 if (ef->strbase) 851 free(ef->strbase, M_LINKER); 852 } 853 854 static void 855 link_elf_unload_preload(linker_file_t file) 856 { 857 if (file->filename) 858 preload_delete_name(file->filename); 859 } 860 861 static const char * 862 symbol_name(elf_file_t ef, Elf_Word r_info) 863 { 864 const Elf_Sym *ref; 865 866 if (ELF_R_SYM(r_info)) { 867 ref = ef->symtab + ELF_R_SYM(r_info); 868 return ef->strtab + ref->st_name; 869 } else 870 return NULL; 871 } 872 873 static int 874 relocate_file(elf_file_t ef) 875 { 876 const Elf_Rel *rellim; 877 const Elf_Rel *rel; 878 const Elf_Rela *relalim; 879 const Elf_Rela *rela; 880 const char *symname; 881 882 /* Perform relocations without addend if there are any: */ 883 rel = ef->rel; 884 if (rel) { 885 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize); 886 while (rel < rellim) { 887 symname = symbol_name(ef, rel->r_info); 888 if (elf_reloc(&ef->lf, rel, ELF_RELOC_REL, symname)) { 889 printf("link_elf: symbol %s undefined\n", symname); 890 return ENOENT; 891 } 892 rel++; 893 } 894 } 895 896 /* Perform relocations with addend if there are any: */ 897 rela = ef->rela; 898 if (rela) { 899 relalim = (const Elf_Rela *)((const char *)ef->rela + ef->relasize); 900 while (rela < relalim) { 901 symname = symbol_name(ef, rela->r_info); 902 if (elf_reloc(&ef->lf, rela, ELF_RELOC_RELA, symname)) { 903 printf("link_elf: symbol %s undefined\n", symname); 904 return ENOENT; 905 } 906 rela++; 907 } 908 } 909 910 /* Perform PLT relocations without addend if there are any: */ 911 rel = ef->pltrel; 912 if (rel) { 913 rellim = (const Elf_Rel *)((const char *)ef->pltrel + ef->pltrelsize); 914 while (rel < rellim) { 915 symname = symbol_name(ef, rel->r_info); 916 if (elf_reloc(&ef->lf, rel, ELF_RELOC_REL, symname)) { 917 printf("link_elf: symbol %s undefined\n", symname); 918 return ENOENT; 919 } 920 rel++; 921 } 922 } 923 924 /* Perform relocations with addend if there are any: */ 925 rela = ef->pltrela; 926 if (rela) { 927 relalim = (const Elf_Rela *)((const char *)ef->pltrela + ef->pltrelasize); 928 while (rela < relalim) { 929 symname = symbol_name(ef, rela->r_info); 930 if (elf_reloc(&ef->lf, rela, ELF_RELOC_RELA, symname)) { 931 printf("link_elf: symbol %s undefined\n", symname); 932 return ENOENT; 933 } 934 rela++; 935 } 936 } 937 938 return 0; 939 } 940 941 /* 942 * Hash function for symbol table lookup. Don't even think about changing 943 * this. It is specified by the System V ABI. 944 */ 945 static unsigned long 946 elf_hash(const char *name) 947 { 948 const unsigned char *p = (const unsigned char *) name; 949 unsigned long h = 0; 950 unsigned long g; 951 952 while (*p != '\0') { 953 h = (h << 4) + *p++; 954 if ((g = h & 0xf0000000) != 0) 955 h ^= g >> 24; 956 h &= ~g; 957 } 958 return h; 959 } 960 961 int 962 link_elf_lookup_symbol(linker_file_t lf, const char* name, c_linker_sym_t* sym) 963 { 964 elf_file_t ef = (elf_file_t) lf; 965 unsigned long symnum; 966 const Elf_Sym* symp; 967 const char *strp; 968 unsigned long hash; 969 int i; 970 971 /* First, search hashed global symbols */ 972 hash = elf_hash(name); 973 symnum = ef->buckets[hash % ef->nbuckets]; 974 975 while (symnum != STN_UNDEF) { 976 if (symnum >= ef->nchains) { 977 printf("link_elf_lookup_symbol: corrupt symbol table\n"); 978 return ENOENT; 979 } 980 981 symp = ef->symtab + symnum; 982 if (symp->st_name == 0) { 983 printf("link_elf_lookup_symbol: corrupt symbol table\n"); 984 return ENOENT; 985 } 986 987 strp = ef->strtab + symp->st_name; 988 989 if (strcmp(name, strp) == 0) { 990 if (symp->st_shndx != SHN_UNDEF || 991 (symp->st_value != 0 && 992 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) { 993 *sym = (c_linker_sym_t) symp; 994 return 0; 995 } else 996 return ENOENT; 997 } 998 999 symnum = ef->chains[symnum]; 1000 } 1001 1002 /* If we have not found it, look at the full table (if loaded) */ 1003 if (ef->symtab == ef->ddbsymtab) 1004 return ENOENT; 1005 1006 /* Exhaustive search */ 1007 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1008 strp = ef->ddbstrtab + symp->st_name; 1009 if (strcmp(name, strp) == 0) { 1010 if (symp->st_shndx != SHN_UNDEF || 1011 (symp->st_value != 0 && 1012 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) { 1013 *sym = (c_linker_sym_t) symp; 1014 return 0; 1015 } else 1016 return ENOENT; 1017 } 1018 } 1019 1020 return ENOENT; 1021 } 1022 1023 static int 1024 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, linker_symval_t* symval) 1025 { 1026 elf_file_t ef = (elf_file_t) lf; 1027 const Elf_Sym* es = (const Elf_Sym*) sym; 1028 1029 if (es >= ef->symtab && ((es - ef->symtab) < ef->nchains)) { 1030 symval->name = ef->strtab + es->st_name; 1031 symval->value = (caddr_t) ef->address + es->st_value; 1032 symval->size = es->st_size; 1033 return 0; 1034 } 1035 if (ef->symtab == ef->ddbsymtab) 1036 return ENOENT; 1037 if (es >= ef->ddbsymtab && ((es - ef->ddbsymtab) < ef->ddbsymcnt)) { 1038 symval->name = ef->ddbstrtab + es->st_name; 1039 symval->value = (caddr_t) ef->address + es->st_value; 1040 symval->size = es->st_size; 1041 return 0; 1042 } 1043 return ENOENT; 1044 } 1045 1046 static int 1047 link_elf_search_symbol(linker_file_t lf, caddr_t value, 1048 c_linker_sym_t* sym, long* diffp) 1049 { 1050 elf_file_t ef = (elf_file_t) lf; 1051 u_long off = (uintptr_t) (void *) value; 1052 u_long diff = off; 1053 u_long st_value; 1054 const Elf_Sym* es; 1055 const Elf_Sym* best = 0; 1056 int i; 1057 1058 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) { 1059 if (es->st_name == 0) 1060 continue; 1061 st_value = es->st_value + (uintptr_t) (void *) ef->address; 1062 if (off >= st_value) { 1063 if (off - st_value < diff) { 1064 diff = off - st_value; 1065 best = es; 1066 if (diff == 0) 1067 break; 1068 } else if (off - st_value == diff) { 1069 best = es; 1070 } 1071 } 1072 } 1073 if (best == 0) 1074 *diffp = off; 1075 else 1076 *diffp = diff; 1077 *sym = (c_linker_sym_t) best; 1078 1079 return 0; 1080 } 1081 1082 /* 1083 * Look up a linker set on an ELF system. 1084 */ 1085 static int 1086 link_elf_lookup_set(linker_file_t lf, const char *name, 1087 void ***startp, void ***stopp, int *countp) 1088 { 1089 c_linker_sym_t sym; 1090 linker_symval_t symval; 1091 char *setsym; 1092 void **start, **stop; 1093 int len, error = 0, count; 1094 1095 len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */ 1096 setsym = malloc(len, M_LINKER, M_WAITOK); 1097 if (setsym == NULL) 1098 return ENOMEM; 1099 1100 /* get address of first entry */ 1101 snprintf(setsym, len, "%s%s", "__start_set_", name); 1102 error = link_elf_lookup_symbol(lf, setsym, &sym); 1103 if (error) 1104 goto out; 1105 link_elf_symbol_values(lf, sym, &symval); 1106 if (symval.value == 0) { 1107 error = ESRCH; 1108 goto out; 1109 } 1110 start = (void **)symval.value; 1111 1112 /* get address of last entry */ 1113 snprintf(setsym, len, "%s%s", "__stop_set_", name); 1114 error = link_elf_lookup_symbol(lf, setsym, &sym); 1115 if (error) 1116 goto out; 1117 link_elf_symbol_values(lf, sym, &symval); 1118 if (symval.value == 0) { 1119 error = ESRCH; 1120 goto out; 1121 } 1122 stop = (void **)symval.value; 1123 1124 /* and the number of entries */ 1125 count = stop - start; 1126 1127 /* and copy out */ 1128 if (startp) 1129 *startp = start; 1130 if (stopp) 1131 *stopp = stop; 1132 if (countp) 1133 *countp = count; 1134 1135 out: 1136 free(setsym, M_LINKER); 1137 return error; 1138 } 1139