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