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 #ifdef GPROF 45 #include <machine/profile.h> 46 #endif 47 48 #include <vm/vm.h> 49 #include <vm/vm_param.h> 50 #ifdef SPARSE_MAPPING 51 #include <vm/vm_object.h> 52 #include <vm/vm_kern.h> 53 #include <vm/vm_extern.h> 54 #endif 55 #include <vm/pmap.h> 56 #include <vm/vm_map.h> 57 58 #include <sys/link_elf.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_Hashelt nbuckets; /* DT_HASH info */ 71 Elf_Hashelt nchains; 72 const Elf_Hashelt* buckets; 73 const Elf_Hashelt* 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_common_finish(linker_file_t); 100 static int link_elf_link_preload(linker_class_t cls, 101 const char*, linker_file_t*); 102 static int link_elf_link_preload_finish(linker_file_t); 103 static int link_elf_load_file(linker_class_t, const char*, linker_file_t*); 104 static int link_elf_lookup_symbol(linker_file_t, const char*, 105 c_linker_sym_t*); 106 static int link_elf_symbol_values(linker_file_t, c_linker_sym_t, linker_symval_t*); 107 static int link_elf_search_symbol(linker_file_t, caddr_t value, 108 c_linker_sym_t* sym, long* diffp); 109 110 static void link_elf_unload_file(linker_file_t); 111 static void link_elf_unload_preload(linker_file_t); 112 static int link_elf_lookup_set(linker_file_t, const char *, 113 void ***, void ***, int *); 114 static int link_elf_each_function_name(linker_file_t, 115 int (*)(const char *, void *), 116 void *); 117 118 static kobj_method_t link_elf_methods[] = { 119 KOBJMETHOD(linker_lookup_symbol, link_elf_lookup_symbol), 120 KOBJMETHOD(linker_symbol_values, link_elf_symbol_values), 121 KOBJMETHOD(linker_search_symbol, link_elf_search_symbol), 122 KOBJMETHOD(linker_unload, link_elf_unload_file), 123 KOBJMETHOD(linker_load_file, link_elf_load_file), 124 KOBJMETHOD(linker_link_preload, link_elf_link_preload), 125 KOBJMETHOD(linker_link_preload_finish, link_elf_link_preload_finish), 126 KOBJMETHOD(linker_lookup_set, link_elf_lookup_set), 127 KOBJMETHOD(linker_each_function_name, link_elf_each_function_name), 128 { 0, 0 } 129 }; 130 131 static struct linker_class link_elf_class = { 132 #if ELF_TARG_CLASS == ELFCLASS32 133 "elf32", 134 #else 135 "elf64", 136 #endif 137 link_elf_methods, sizeof(struct elf_file) 138 }; 139 140 static int parse_dynamic(elf_file_t ef); 141 static int relocate_file(elf_file_t ef); 142 static int link_elf_preload_parse_symbols(elf_file_t ef); 143 144 #ifdef DDB 145 static void r_debug_state(struct r_debug *dummy_one, 146 struct link_map *dummy_two); 147 148 /* 149 * A list of loaded modules for GDB to use for loading symbols. 150 */ 151 struct r_debug r_debug; 152 153 #define GDB_STATE(s) r_debug.r_state = s; r_debug_state(NULL, NULL); 154 155 /* 156 * Function for the debugger to set a breakpoint on to gain control. 157 */ 158 static void 159 r_debug_state(struct r_debug *dummy_one __unused, 160 struct link_map *dummy_two __unused) 161 { 162 } 163 164 static void 165 link_elf_add_gdb(struct link_map *l) 166 { 167 struct link_map *prev; 168 169 l->l_next = NULL; 170 171 if (r_debug.r_map == NULL) { 172 /* Add first. */ 173 l->l_prev = NULL; 174 r_debug.r_map = l; 175 } else { 176 /* Append to list. */ 177 for (prev = r_debug.r_map; prev->l_next != NULL; prev = prev->l_next) 178 ; 179 l->l_prev = prev; 180 prev->l_next = l; 181 } 182 } 183 184 static void 185 link_elf_delete_gdb(struct link_map *l) 186 { 187 if (l->l_prev == NULL) { 188 /* Remove first. */ 189 if ((r_debug.r_map = l->l_next) != NULL) 190 l->l_next->l_prev = NULL; 191 } else { 192 /* Remove any but first. */ 193 if ((l->l_prev->l_next = l->l_next) != NULL) 194 l->l_next->l_prev = l->l_prev; 195 } 196 } 197 #endif /* DDB */ 198 199 #ifdef __ia64__ 200 Elf_Addr link_elf_get_gp(linker_file_t); 201 #endif 202 203 /* 204 * The kernel symbol table starts here. 205 */ 206 extern struct _dynamic _DYNAMIC; 207 208 static void 209 link_elf_error(const char *s) 210 { 211 printf("kldload: %s\n", s); 212 } 213 214 /* 215 * Actions performed after linking/loading both the preloaded kernel and any 216 * modules; whether preloaded or dynamicly loaded. 217 */ 218 static int 219 link_elf_link_common_finish(linker_file_t lf) 220 { 221 #ifdef DDB 222 elf_file_t ef = (elf_file_t)lf; 223 char *newfilename; 224 #endif 225 int error; 226 227 /* Notify MD code that a module is being loaded. */ 228 error = elf_cpu_load_file(lf); 229 if (error) 230 return (error); 231 232 #ifdef DDB 233 GDB_STATE(RT_ADD); 234 ef->gdb.l_addr = lf->address; 235 newfilename = malloc(strlen(lf->filename) + 1, M_LINKER, M_WAITOK); 236 strcpy(newfilename, lf->filename); 237 ef->gdb.l_name = newfilename; 238 ef->gdb.l_ld = ef->dynamic; 239 link_elf_add_gdb(&ef->gdb); 240 GDB_STATE(RT_CONSISTENT); 241 #endif 242 243 return (0); 244 } 245 246 static void 247 link_elf_init(void* arg) 248 { 249 Elf_Dyn *dp; 250 caddr_t modptr, baseptr, sizeptr; 251 elf_file_t ef; 252 char *modname; 253 254 linker_add_class(&link_elf_class); 255 256 dp = (Elf_Dyn*) &_DYNAMIC; 257 modname = NULL; 258 modptr = preload_search_by_type("elf kernel"); 259 if (modptr) 260 modname = (char *)preload_search_info(modptr, MODINFO_NAME); 261 if (modname == NULL) 262 modname = "kernel"; 263 linker_kernel_file = linker_make_file(modname, &link_elf_class); 264 if (linker_kernel_file == NULL) 265 panic("link_elf_init: Can't create linker structures for kernel"); 266 267 ef = (elf_file_t) linker_kernel_file; 268 ef->preloaded = 1; 269 ef->address = 0; 270 #ifdef SPARSE_MAPPING 271 ef->object = 0; 272 #endif 273 ef->dynamic = dp; 274 275 if (dp) 276 parse_dynamic(ef); 277 linker_kernel_file->address = (caddr_t) KERNBASE; 278 linker_kernel_file->size = -(intptr_t)linker_kernel_file->address; 279 280 if (modptr) { 281 ef->modptr = modptr; 282 baseptr = preload_search_info(modptr, MODINFO_ADDR); 283 if (baseptr) 284 linker_kernel_file->address = *(caddr_t *)baseptr; 285 sizeptr = preload_search_info(modptr, MODINFO_SIZE); 286 if (sizeptr) 287 linker_kernel_file->size = *(size_t *)sizeptr; 288 } 289 (void)link_elf_preload_parse_symbols(ef); 290 291 #ifdef DDB 292 r_debug.r_map = NULL; 293 r_debug.r_brk = r_debug_state; 294 r_debug.r_state = RT_CONSISTENT; 295 #endif 296 297 (void)link_elf_link_common_finish(linker_kernel_file); 298 } 299 300 SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_SECOND, link_elf_init, 0); 301 302 static int 303 link_elf_preload_parse_symbols(elf_file_t ef) 304 { 305 caddr_t pointer; 306 caddr_t ssym, esym, base; 307 caddr_t strtab; 308 int strcnt; 309 Elf_Sym* symtab; 310 int symcnt; 311 312 if (ef->modptr == NULL) 313 return 0; 314 pointer = preload_search_info(ef->modptr, MODINFO_METADATA|MODINFOMD_SSYM); 315 if (pointer == NULL) 316 return 0; 317 ssym = *(caddr_t *)pointer; 318 pointer = preload_search_info(ef->modptr, MODINFO_METADATA|MODINFOMD_ESYM); 319 if (pointer == NULL) 320 return 0; 321 esym = *(caddr_t *)pointer; 322 323 base = ssym; 324 325 symcnt = *(long *)base; 326 base += sizeof(long); 327 symtab = (Elf_Sym *)base; 328 base += roundup(symcnt, sizeof(long)); 329 330 if (base > esym || base < ssym) { 331 printf("Symbols are corrupt!\n"); 332 return EINVAL; 333 } 334 335 strcnt = *(long *)base; 336 base += sizeof(long); 337 strtab = base; 338 base += roundup(strcnt, sizeof(long)); 339 340 if (base > esym || base < ssym) { 341 printf("Symbols are corrupt!\n"); 342 return EINVAL; 343 } 344 345 ef->ddbsymtab = symtab; 346 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym); 347 ef->ddbstrtab = strtab; 348 ef->ddbstrcnt = strcnt; 349 350 return 0; 351 } 352 353 static int 354 parse_dynamic(elf_file_t ef) 355 { 356 Elf_Dyn *dp; 357 int plttype = DT_REL; 358 359 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) { 360 switch (dp->d_tag) { 361 case DT_HASH: 362 { 363 /* From src/libexec/rtld-elf/rtld.c */ 364 const Elf_Hashelt *hashtab = (const Elf_Hashelt *) 365 (ef->address + dp->d_un.d_ptr); 366 ef->nbuckets = hashtab[0]; 367 ef->nchains = hashtab[1]; 368 ef->buckets = hashtab + 2; 369 ef->chains = ef->buckets + ef->nbuckets; 370 break; 371 } 372 case DT_STRTAB: 373 ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr); 374 break; 375 case DT_STRSZ: 376 ef->strsz = dp->d_un.d_val; 377 break; 378 case DT_SYMTAB: 379 ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr); 380 break; 381 case DT_SYMENT: 382 if (dp->d_un.d_val != sizeof(Elf_Sym)) 383 return ENOEXEC; 384 break; 385 case DT_PLTGOT: 386 ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr); 387 break; 388 case DT_REL: 389 ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr); 390 break; 391 case DT_RELSZ: 392 ef->relsize = dp->d_un.d_val; 393 break; 394 case DT_RELENT: 395 if (dp->d_un.d_val != sizeof(Elf_Rel)) 396 return ENOEXEC; 397 break; 398 case DT_JMPREL: 399 ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr); 400 break; 401 case DT_PLTRELSZ: 402 ef->pltrelsize = dp->d_un.d_val; 403 break; 404 case DT_RELA: 405 ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr); 406 break; 407 case DT_RELASZ: 408 ef->relasize = dp->d_un.d_val; 409 break; 410 case DT_RELAENT: 411 if (dp->d_un.d_val != sizeof(Elf_Rela)) 412 return ENOEXEC; 413 break; 414 case DT_PLTREL: 415 plttype = dp->d_un.d_val; 416 if (plttype != DT_REL && plttype != DT_RELA) 417 return ENOEXEC; 418 break; 419 #ifdef DDB 420 case DT_DEBUG: 421 dp->d_un.d_ptr = (Elf_Addr) &r_debug; 422 break; 423 #endif 424 } 425 } 426 427 if (plttype == DT_RELA) { 428 ef->pltrela = (const Elf_Rela *) ef->pltrel; 429 ef->pltrel = NULL; 430 ef->pltrelasize = ef->pltrelsize; 431 ef->pltrelsize = 0; 432 } 433 434 ef->ddbsymtab = ef->symtab; 435 ef->ddbsymcnt = ef->nchains; 436 ef->ddbstrtab = ef->strtab; 437 ef->ddbstrcnt = ef->strsz; 438 439 return 0; 440 } 441 442 static int 443 link_elf_link_preload(linker_class_t cls, 444 const char* filename, linker_file_t *result) 445 { 446 caddr_t modptr, baseptr, sizeptr, dynptr; 447 char *type; 448 elf_file_t ef; 449 linker_file_t lf; 450 int error; 451 vm_offset_t dp; 452 453 /* Look to see if we have the file preloaded */ 454 modptr = preload_search_by_name(filename); 455 if (modptr == NULL) 456 return ENOENT; 457 458 type = (char *)preload_search_info(modptr, MODINFO_TYPE); 459 baseptr = preload_search_info(modptr, MODINFO_ADDR); 460 sizeptr = preload_search_info(modptr, MODINFO_SIZE); 461 dynptr = preload_search_info(modptr, MODINFO_METADATA|MODINFOMD_DYNAMIC); 462 if (type == NULL || strcmp(type, "elf module") != 0) 463 return (EFTYPE); 464 if (baseptr == NULL || sizeptr == NULL || dynptr == NULL) 465 return (EINVAL); 466 467 lf = linker_make_file(filename, &link_elf_class); 468 if (lf == NULL) { 469 return ENOMEM; 470 } 471 472 ef = (elf_file_t) lf; 473 ef->preloaded = 1; 474 ef->modptr = modptr; 475 ef->address = *(caddr_t *)baseptr; 476 #ifdef SPARSE_MAPPING 477 ef->object = 0; 478 #endif 479 dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr; 480 ef->dynamic = (Elf_Dyn *)dp; 481 lf->address = ef->address; 482 lf->size = *(size_t *)sizeptr; 483 484 error = parse_dynamic(ef); 485 if (error) { 486 linker_file_unload(lf); 487 return error; 488 } 489 *result = lf; 490 return (0); 491 } 492 493 static int 494 link_elf_link_preload_finish(linker_file_t lf) 495 { 496 elf_file_t ef; 497 int error; 498 499 ef = (elf_file_t) lf; 500 #if 0 /* this will be more trouble than it's worth for now */ 501 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) { 502 if (dp->d_tag != DT_NEEDED) 503 continue; 504 modname = ef->strtab + dp->d_un.d_val; 505 error = linker_load_module(modname, lf); 506 if (error) 507 goto out; 508 } 509 #endif 510 error = relocate_file(ef); 511 if (error) 512 return error; 513 (void)link_elf_preload_parse_symbols(ef); 514 515 return (link_elf_link_common_finish(lf)); 516 } 517 518 static int 519 link_elf_load_file(linker_class_t cls, const char* filename, 520 linker_file_t* result) 521 { 522 struct nameidata nd; 523 struct thread* td = curthread; /* XXX */ 524 Elf_Ehdr *hdr; 525 caddr_t firstpage; 526 int nbytes, i; 527 Elf_Phdr *phdr; 528 Elf_Phdr *phlimit; 529 Elf_Phdr *segs[2]; 530 int nsegs; 531 Elf_Phdr *phdyn; 532 Elf_Phdr *phphdr; 533 caddr_t mapbase; 534 size_t mapsize; 535 Elf_Off base_offset; 536 Elf_Addr base_vaddr; 537 Elf_Addr base_vlimit; 538 int error = 0; 539 int resid, flags; 540 elf_file_t ef; 541 linker_file_t lf; 542 Elf_Shdr *shdr; 543 int symtabindex; 544 int symstrindex; 545 int symcnt; 546 int strcnt; 547 548 GIANT_REQUIRED; 549 550 shdr = NULL; 551 lf = NULL; 552 553 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td); 554 flags = FREAD; 555 error = vn_open(&nd, &flags, 0); 556 if (error) 557 return error; 558 NDFREE(&nd, NDF_ONLY_PNBUF); 559 560 /* 561 * Read the elf header from the file. 562 */ 563 firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK); 564 if (firstpage == NULL) { 565 error = ENOMEM; 566 goto out; 567 } 568 hdr = (Elf_Ehdr *)firstpage; 569 error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0, 570 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 571 &resid, td); 572 nbytes = PAGE_SIZE - resid; 573 if (error) 574 goto out; 575 576 if (!IS_ELF(*hdr)) { 577 error = ENOEXEC; 578 goto out; 579 } 580 581 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS 582 || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) { 583 link_elf_error("Unsupported file layout"); 584 error = ENOEXEC; 585 goto out; 586 } 587 if (hdr->e_ident[EI_VERSION] != EV_CURRENT 588 || hdr->e_version != EV_CURRENT) { 589 link_elf_error("Unsupported file version"); 590 error = ENOEXEC; 591 goto out; 592 } 593 if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) { 594 link_elf_error("Unsupported file type"); 595 error = ENOEXEC; 596 goto out; 597 } 598 if (hdr->e_machine != ELF_TARG_MACH) { 599 link_elf_error("Unsupported machine"); 600 error = ENOEXEC; 601 goto out; 602 } 603 604 /* 605 * We rely on the program header being in the first page. This is 606 * not strictly required by the ABI specification, but it seems to 607 * always true in practice. And, it simplifies things considerably. 608 */ 609 if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) && 610 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) && 611 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes))) 612 link_elf_error("Unreadable program headers"); 613 614 /* 615 * Scan the program header entries, and save key information. 616 * 617 * We rely on there being exactly two load segments, text and data, 618 * in that order. 619 */ 620 phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff); 621 phlimit = phdr + hdr->e_phnum; 622 nsegs = 0; 623 phdyn = NULL; 624 phphdr = NULL; 625 while (phdr < phlimit) { 626 switch (phdr->p_type) { 627 628 case PT_LOAD: 629 if (nsegs == 2) { 630 link_elf_error("Too many sections"); 631 error = ENOEXEC; 632 goto out; 633 } 634 segs[nsegs] = phdr; 635 ++nsegs; 636 break; 637 638 case PT_PHDR: 639 phphdr = phdr; 640 break; 641 642 case PT_DYNAMIC: 643 phdyn = phdr; 644 break; 645 646 case PT_INTERP: 647 link_elf_error("Unsupported file type"); 648 error = ENOEXEC; 649 goto out; 650 } 651 652 ++phdr; 653 } 654 if (phdyn == NULL) { 655 link_elf_error("Object is not dynamically-linked"); 656 error = ENOEXEC; 657 goto out; 658 } 659 660 /* 661 * Allocate the entire address space of the object, to stake out our 662 * contiguous region, and to establish the base address for relocation. 663 */ 664 base_offset = trunc_page(segs[0]->p_offset); 665 base_vaddr = trunc_page(segs[0]->p_vaddr); 666 base_vlimit = round_page(segs[1]->p_vaddr + segs[1]->p_memsz); 667 mapsize = base_vlimit - base_vaddr; 668 669 lf = linker_make_file(filename, &link_elf_class); 670 if (!lf) { 671 error = ENOMEM; 672 goto out; 673 } 674 675 ef = (elf_file_t) lf; 676 #ifdef SPARSE_MAPPING 677 ef->object = vm_object_allocate(OBJT_DEFAULT, mapsize >> PAGE_SHIFT); 678 if (ef->object == NULL) { 679 error = ENOMEM; 680 goto out; 681 } 682 vm_object_reference(ef->object); 683 ef->address = (caddr_t) vm_map_min(kernel_map); 684 error = vm_map_find(kernel_map, ef->object, 0, 685 (vm_offset_t *) &ef->address, 686 mapsize, 1, 687 VM_PROT_ALL, VM_PROT_ALL, 0); 688 if (error) { 689 vm_object_deallocate(ef->object); 690 ef->object = 0; 691 goto out; 692 } 693 #else 694 ef->address = malloc(mapsize, M_LINKER, M_WAITOK); 695 if (!ef->address) { 696 error = ENOMEM; 697 goto out; 698 } 699 #endif 700 mapbase = ef->address; 701 702 /* 703 * Read the text and data sections and zero the bss. 704 */ 705 for (i = 0; i < 2; i++) { 706 caddr_t segbase = mapbase + segs[i]->p_vaddr - base_vaddr; 707 error = vn_rdwr(UIO_READ, nd.ni_vp, 708 segbase, segs[i]->p_filesz, segs[i]->p_offset, 709 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 710 &resid, td); 711 if (error) { 712 goto out; 713 } 714 bzero(segbase + segs[i]->p_filesz, 715 segs[i]->p_memsz - segs[i]->p_filesz); 716 717 #ifdef SPARSE_MAPPING 718 /* 719 * Wire down the pages 720 */ 721 vm_map_wire(kernel_map, 722 (vm_offset_t) segbase, 723 (vm_offset_t) segbase + segs[i]->p_memsz, 724 FALSE); 725 #endif 726 } 727 728 #ifdef GPROF 729 /* Update profiling information with the new text segment. */ 730 kmupetext((uintfptr_t)(mapbase + segs[0]->p_vaddr - base_vaddr + 731 segs[0]->p_memsz)); 732 #endif 733 734 ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr); 735 736 lf->address = ef->address; 737 lf->size = mapsize; 738 739 error = parse_dynamic(ef); 740 if (error) 741 goto out; 742 error = linker_load_dependencies(lf); 743 if (error) 744 goto out; 745 #if 0 /* this will be more trouble than it's worth for now */ 746 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) { 747 if (dp->d_tag != DT_NEEDED) 748 continue; 749 modname = ef->strtab + dp->d_un.d_val; 750 error = linker_load_module(modname, lf); 751 if (error) 752 goto out; 753 } 754 #endif 755 error = relocate_file(ef); 756 if (error) 757 goto out; 758 759 /* Try and load the symbol table if it's present. (you can strip it!) */ 760 nbytes = hdr->e_shnum * hdr->e_shentsize; 761 if (nbytes == 0 || hdr->e_shoff == 0) 762 goto nosyms; 763 shdr = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO); 764 if (shdr == NULL) { 765 error = ENOMEM; 766 goto out; 767 } 768 error = vn_rdwr(UIO_READ, nd.ni_vp, 769 (caddr_t)shdr, nbytes, hdr->e_shoff, 770 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 771 &resid, td); 772 if (error) 773 goto out; 774 symtabindex = -1; 775 symstrindex = -1; 776 for (i = 0; i < hdr->e_shnum; i++) { 777 if (shdr[i].sh_type == SHT_SYMTAB) { 778 symtabindex = i; 779 symstrindex = shdr[i].sh_link; 780 } 781 } 782 if (symtabindex < 0 || symstrindex < 0) 783 goto nosyms; 784 785 symcnt = shdr[symtabindex].sh_size; 786 ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK); 787 strcnt = shdr[symstrindex].sh_size; 788 ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK); 789 790 if (ef->symbase == NULL || ef->strbase == NULL) { 791 error = ENOMEM; 792 goto out; 793 } 794 error = vn_rdwr(UIO_READ, nd.ni_vp, 795 ef->symbase, symcnt, shdr[symtabindex].sh_offset, 796 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 797 &resid, td); 798 if (error) 799 goto out; 800 error = vn_rdwr(UIO_READ, nd.ni_vp, 801 ef->strbase, strcnt, shdr[symstrindex].sh_offset, 802 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 803 &resid, td); 804 if (error) 805 goto out; 806 807 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym); 808 ef->ddbsymtab = (const Elf_Sym *)ef->symbase; 809 ef->ddbstrcnt = strcnt; 810 ef->ddbstrtab = ef->strbase; 811 812 error = link_elf_link_common_finish(lf); 813 if (error) 814 goto out; 815 816 nosyms: 817 818 *result = lf; 819 820 out: 821 if (error && lf) 822 linker_file_unload(lf); 823 if (shdr) 824 free(shdr, M_LINKER); 825 if (firstpage) 826 free(firstpage, M_LINKER); 827 VOP_UNLOCK(nd.ni_vp, 0, td); 828 vn_close(nd.ni_vp, FREAD, td->td_ucred, td); 829 830 return error; 831 } 832 833 static void 834 link_elf_unload_file(linker_file_t file) 835 { 836 elf_file_t ef = (elf_file_t) file; 837 838 #ifdef DDB 839 if (ef->gdb.l_ld) { 840 GDB_STATE(RT_DELETE); 841 free((void *)(uintptr_t)ef->gdb.l_name, M_LINKER); 842 link_elf_delete_gdb(&ef->gdb); 843 GDB_STATE(RT_CONSISTENT); 844 } 845 #endif 846 847 /* Notify MD code that a module is being unloaded. */ 848 elf_cpu_unload_file(file); 849 850 if (ef->preloaded) { 851 link_elf_unload_preload(file); 852 return; 853 } 854 855 #ifdef SPARSE_MAPPING 856 if (ef->object) { 857 vm_map_remove(kernel_map, (vm_offset_t) ef->address, 858 (vm_offset_t) ef->address 859 + (ef->object->size << PAGE_SHIFT)); 860 vm_object_deallocate(ef->object); 861 } 862 #else 863 if (ef->address) 864 free(ef->address, M_LINKER); 865 #endif 866 if (ef->symbase) 867 free(ef->symbase, M_LINKER); 868 if (ef->strbase) 869 free(ef->strbase, M_LINKER); 870 } 871 872 static void 873 link_elf_unload_preload(linker_file_t file) 874 { 875 if (file->filename) 876 preload_delete_name(file->filename); 877 } 878 879 static const char * 880 symbol_name(elf_file_t ef, Elf_Word r_info) 881 { 882 const Elf_Sym *ref; 883 884 if (ELF_R_SYM(r_info)) { 885 ref = ef->symtab + ELF_R_SYM(r_info); 886 return ef->strtab + ref->st_name; 887 } else 888 return NULL; 889 } 890 891 static int 892 relocate_file(elf_file_t ef) 893 { 894 const Elf_Rel *rellim; 895 const Elf_Rel *rel; 896 const Elf_Rela *relalim; 897 const Elf_Rela *rela; 898 const char *symname; 899 900 /* Perform relocations without addend if there are any: */ 901 rel = ef->rel; 902 if (rel) { 903 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize); 904 while (rel < rellim) { 905 if (elf_reloc(&ef->lf, rel, ELF_RELOC_REL)) { 906 symname = symbol_name(ef, rel->r_info); 907 printf("link_elf: symbol %s undefined\n", symname); 908 return ENOENT; 909 } 910 rel++; 911 } 912 } 913 914 /* Perform relocations with addend if there are any: */ 915 rela = ef->rela; 916 if (rela) { 917 relalim = (const Elf_Rela *)((const char *)ef->rela + ef->relasize); 918 while (rela < relalim) { 919 if (elf_reloc(&ef->lf, rela, ELF_RELOC_RELA)) { 920 symname = symbol_name(ef, rela->r_info); 921 printf("link_elf: symbol %s undefined\n", symname); 922 return ENOENT; 923 } 924 rela++; 925 } 926 } 927 928 /* Perform PLT relocations without addend if there are any: */ 929 rel = ef->pltrel; 930 if (rel) { 931 rellim = (const Elf_Rel *)((const char *)ef->pltrel + ef->pltrelsize); 932 while (rel < rellim) { 933 if (elf_reloc(&ef->lf, rel, ELF_RELOC_REL)) { 934 symname = symbol_name(ef, rel->r_info); 935 printf("link_elf: symbol %s undefined\n", symname); 936 return ENOENT; 937 } 938 rel++; 939 } 940 } 941 942 /* Perform relocations with addend if there are any: */ 943 rela = ef->pltrela; 944 if (rela) { 945 relalim = (const Elf_Rela *)((const char *)ef->pltrela + ef->pltrelasize); 946 while (rela < relalim) { 947 if (elf_reloc(&ef->lf, rela, ELF_RELOC_RELA)) { 948 symname = symbol_name(ef, rela->r_info); 949 printf("link_elf: symbol %s undefined\n", symname); 950 return ENOENT; 951 } 952 rela++; 953 } 954 } 955 956 return 0; 957 } 958 959 /* 960 * Hash function for symbol table lookup. Don't even think about changing 961 * this. It is specified by the System V ABI. 962 */ 963 static unsigned long 964 elf_hash(const char *name) 965 { 966 const unsigned char *p = (const unsigned char *) name; 967 unsigned long h = 0; 968 unsigned long g; 969 970 while (*p != '\0') { 971 h = (h << 4) + *p++; 972 if ((g = h & 0xf0000000) != 0) 973 h ^= g >> 24; 974 h &= ~g; 975 } 976 return h; 977 } 978 979 static int 980 link_elf_lookup_symbol(linker_file_t lf, const char* name, c_linker_sym_t* sym) 981 { 982 elf_file_t ef = (elf_file_t) lf; 983 unsigned long symnum; 984 const Elf_Sym* symp; 985 const char *strp; 986 unsigned long hash; 987 int i; 988 989 /* First, search hashed global symbols */ 990 hash = elf_hash(name); 991 symnum = ef->buckets[hash % ef->nbuckets]; 992 993 while (symnum != STN_UNDEF) { 994 if (symnum >= ef->nchains) { 995 printf("link_elf_lookup_symbol: corrupt symbol table\n"); 996 return ENOENT; 997 } 998 999 symp = ef->symtab + symnum; 1000 if (symp->st_name == 0) { 1001 printf("link_elf_lookup_symbol: corrupt symbol table\n"); 1002 return ENOENT; 1003 } 1004 1005 strp = ef->strtab + symp->st_name; 1006 1007 if (strcmp(name, strp) == 0) { 1008 if (symp->st_shndx != SHN_UNDEF || 1009 (symp->st_value != 0 && 1010 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) { 1011 *sym = (c_linker_sym_t) symp; 1012 return 0; 1013 } else 1014 return ENOENT; 1015 } 1016 1017 symnum = ef->chains[symnum]; 1018 } 1019 1020 /* If we have not found it, look at the full table (if loaded) */ 1021 if (ef->symtab == ef->ddbsymtab) 1022 return ENOENT; 1023 1024 /* Exhaustive search */ 1025 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1026 strp = ef->ddbstrtab + symp->st_name; 1027 if (strcmp(name, strp) == 0) { 1028 if (symp->st_shndx != SHN_UNDEF || 1029 (symp->st_value != 0 && 1030 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) { 1031 *sym = (c_linker_sym_t) symp; 1032 return 0; 1033 } else 1034 return ENOENT; 1035 } 1036 } 1037 1038 return ENOENT; 1039 } 1040 1041 static int 1042 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, linker_symval_t* symval) 1043 { 1044 elf_file_t ef = (elf_file_t) lf; 1045 const Elf_Sym* es = (const Elf_Sym*) sym; 1046 1047 if (es >= ef->symtab && es < (ef->symtab + ef->nchains)) { 1048 symval->name = ef->strtab + es->st_name; 1049 symval->value = (caddr_t) ef->address + es->st_value; 1050 symval->size = es->st_size; 1051 return 0; 1052 } 1053 if (ef->symtab == ef->ddbsymtab) 1054 return ENOENT; 1055 if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) { 1056 symval->name = ef->ddbstrtab + es->st_name; 1057 symval->value = (caddr_t) ef->address + es->st_value; 1058 symval->size = es->st_size; 1059 return 0; 1060 } 1061 return ENOENT; 1062 } 1063 1064 static int 1065 link_elf_search_symbol(linker_file_t lf, caddr_t value, 1066 c_linker_sym_t* sym, long* diffp) 1067 { 1068 elf_file_t ef = (elf_file_t) lf; 1069 u_long off = (uintptr_t) (void *) value; 1070 u_long diff = off; 1071 u_long st_value; 1072 const Elf_Sym* es; 1073 const Elf_Sym* best = 0; 1074 int i; 1075 1076 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) { 1077 if (es->st_name == 0) 1078 continue; 1079 st_value = es->st_value + (uintptr_t) (void *) ef->address; 1080 if (off >= st_value) { 1081 if (off - st_value < diff) { 1082 diff = off - st_value; 1083 best = es; 1084 if (diff == 0) 1085 break; 1086 } else if (off - st_value == diff) { 1087 best = es; 1088 } 1089 } 1090 } 1091 if (best == 0) 1092 *diffp = off; 1093 else 1094 *diffp = diff; 1095 *sym = (c_linker_sym_t) best; 1096 1097 return 0; 1098 } 1099 1100 /* 1101 * Look up a linker set on an ELF system. 1102 */ 1103 static int 1104 link_elf_lookup_set(linker_file_t lf, const char *name, 1105 void ***startp, void ***stopp, int *countp) 1106 { 1107 c_linker_sym_t sym; 1108 linker_symval_t symval; 1109 char *setsym; 1110 void **start, **stop; 1111 int len, error = 0, count; 1112 1113 len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */ 1114 setsym = malloc(len, M_LINKER, M_WAITOK); 1115 if (setsym == NULL) 1116 return ENOMEM; 1117 1118 /* get address of first entry */ 1119 snprintf(setsym, len, "%s%s", "__start_set_", name); 1120 error = link_elf_lookup_symbol(lf, setsym, &sym); 1121 if (error) 1122 goto out; 1123 link_elf_symbol_values(lf, sym, &symval); 1124 if (symval.value == 0) { 1125 error = ESRCH; 1126 goto out; 1127 } 1128 start = (void **)symval.value; 1129 1130 /* get address of last entry */ 1131 snprintf(setsym, len, "%s%s", "__stop_set_", name); 1132 error = link_elf_lookup_symbol(lf, setsym, &sym); 1133 if (error) 1134 goto out; 1135 link_elf_symbol_values(lf, sym, &symval); 1136 if (symval.value == 0) { 1137 error = ESRCH; 1138 goto out; 1139 } 1140 stop = (void **)symval.value; 1141 1142 /* and the number of entries */ 1143 count = stop - start; 1144 1145 /* and copy out */ 1146 if (startp) 1147 *startp = start; 1148 if (stopp) 1149 *stopp = stop; 1150 if (countp) 1151 *countp = count; 1152 1153 out: 1154 free(setsym, M_LINKER); 1155 return error; 1156 } 1157 1158 static int 1159 link_elf_each_function_name(linker_file_t file, 1160 int (*callback)(const char *, void *), void *opaque) { 1161 elf_file_t ef = (elf_file_t)file; 1162 const Elf_Sym* symp; 1163 int i, error; 1164 1165 /* Exhaustive search */ 1166 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1167 if (symp->st_value != 0 && 1168 ELF_ST_TYPE(symp->st_info) == STT_FUNC) { 1169 error = callback(ef->ddbstrtab + symp->st_name, opaque); 1170 if (error) 1171 return (error); 1172 } 1173 } 1174 return (0); 1175 } 1176 1177 #ifdef __ia64__ 1178 /* 1179 * Each KLD has its own GP. The GP value for each load module is given by 1180 * DT_PLTGOT on ia64. We need GP to construct function descriptors, but 1181 * don't have direct access to the ELF file structure. The link_elf_get_gp() 1182 * function returns the GP given a pointer to a generic linker file struct. 1183 */ 1184 Elf_Addr 1185 link_elf_get_gp(linker_file_t lf) 1186 { 1187 elf_file_t ef = (elf_file_t)lf; 1188 return (Elf_Addr)ef->got; 1189 } 1190 #endif 1191 1192 const Elf_Sym * 1193 elf_get_sym(linker_file_t lf, Elf_Word symidx) 1194 { 1195 elf_file_t ef = (elf_file_t)lf; 1196 1197 if (symidx >= ef->nchains) 1198 return (NULL); 1199 return (ef->symtab + symidx); 1200 } 1201 1202 const char * 1203 elf_get_symname(linker_file_t lf, Elf_Word symidx) 1204 { 1205 elf_file_t ef = (elf_file_t)lf; 1206 const Elf_Sym *sym; 1207 1208 if (symidx >= ef->nchains) 1209 return (NULL); 1210 sym = ef->symtab + symidx; 1211 return (ef->strtab + sym->st_name); 1212 } 1213 1214 /* 1215 * Symbol lookup function that can be used when the symbol index is known (ie 1216 * in relocations). It uses the symbol index instead of doing a fully fledged 1217 * hash table based lookup when such is valid. For example for local symbols. 1218 * This is not only more efficient, it's also more correct. It's not always 1219 * the case that the symbol can be found through the hash table. 1220 */ 1221 Elf_Addr 1222 elf_lookup(linker_file_t lf, Elf_Word symidx, int deps) 1223 { 1224 elf_file_t ef = (elf_file_t)lf; 1225 const Elf_Sym *sym; 1226 const char *symbol; 1227 1228 /* Don't even try to lookup the symbol if the index is bogus. */ 1229 if (symidx >= ef->nchains) 1230 return (0); 1231 1232 sym = ef->symtab + symidx; 1233 1234 /* 1235 * Don't do a full lookup when the symbol is local. It may even 1236 * fail because it may not be found through the hash table. 1237 */ 1238 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) { 1239 /* Force lookup failure when we have an insanity. */ 1240 if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0) 1241 return (0); 1242 return ((Elf_Addr)ef->address + sym->st_value); 1243 } 1244 1245 /* 1246 * XXX we can avoid doing a hash table based lookup for global 1247 * symbols as well. This however is not always valid, so we'll 1248 * just do it the hard way for now. Performance tweaks can 1249 * always be added. 1250 */ 1251 1252 symbol = ef->strtab + sym->st_name; 1253 1254 /* Force a lookup failure if the symbol name is bogus. */ 1255 if (*symbol == 0) 1256 return (0); 1257 1258 return ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps)); 1259 } 1260