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 #ifdef __AOUT__ 59 #include <nlist.h> 60 #endif 61 #include <link.h> 62 63 #include "linker_if.h" 64 65 typedef struct elf_file { 66 struct linker_file lf; /* Common fields */ 67 int preloaded; /* Was file pre-loaded */ 68 caddr_t address; /* Relocation address */ 69 #ifdef SPARSE_MAPPING 70 vm_object_t object; /* VM object to hold file pages */ 71 #endif 72 Elf_Dyn* dynamic; /* Symbol table etc. */ 73 Elf_Hashelt nbuckets; /* DT_HASH info */ 74 Elf_Hashelt nchains; 75 const Elf_Hashelt* buckets; 76 const Elf_Hashelt* chains; 77 caddr_t hash; 78 caddr_t strtab; /* DT_STRTAB */ 79 int strsz; /* DT_STRSZ */ 80 const Elf_Sym* symtab; /* DT_SYMTAB */ 81 Elf_Addr* got; /* DT_PLTGOT */ 82 const Elf_Rel* pltrel; /* DT_JMPREL */ 83 int pltrelsize; /* DT_PLTRELSZ */ 84 const Elf_Rela* pltrela; /* DT_JMPREL */ 85 int pltrelasize; /* DT_PLTRELSZ */ 86 const Elf_Rel* rel; /* DT_REL */ 87 int relsize; /* DT_RELSZ */ 88 const Elf_Rela* rela; /* DT_RELA */ 89 int relasize; /* DT_RELASZ */ 90 caddr_t modptr; 91 const Elf_Sym* ddbsymtab; /* The symbol table we are using */ 92 long ddbsymcnt; /* Number of symbols */ 93 caddr_t ddbstrtab; /* String table */ 94 long ddbstrcnt; /* number of bytes in string table */ 95 caddr_t symbase; /* malloc'ed symbold base */ 96 caddr_t strbase; /* malloc'ed string base */ 97 #ifdef DDB 98 struct link_map gdb; /* hooks for gdb */ 99 #endif 100 } *elf_file_t; 101 102 static int link_elf_link_preload(linker_class_t cls, 103 const char*, linker_file_t*); 104 static int link_elf_link_preload_finish(linker_file_t); 105 static int link_elf_load_file(linker_class_t, const char*, linker_file_t*); 106 static int link_elf_lookup_symbol(linker_file_t, const char*, 107 c_linker_sym_t*); 108 static int link_elf_symbol_values(linker_file_t, c_linker_sym_t, linker_symval_t*); 109 static int link_elf_search_symbol(linker_file_t, caddr_t value, 110 c_linker_sym_t* sym, long* diffp); 111 112 static void link_elf_unload_file(linker_file_t); 113 static void link_elf_unload_preload(linker_file_t); 114 static int link_elf_lookup_set(linker_file_t, const char *, 115 void ***, void ***, int *); 116 static int link_elf_each_function_name(linker_file_t, 117 int (*)(const char *, void *), 118 void *); 119 120 static kobj_method_t link_elf_methods[] = { 121 KOBJMETHOD(linker_lookup_symbol, link_elf_lookup_symbol), 122 KOBJMETHOD(linker_symbol_values, link_elf_symbol_values), 123 KOBJMETHOD(linker_search_symbol, link_elf_search_symbol), 124 KOBJMETHOD(linker_unload, link_elf_unload_file), 125 KOBJMETHOD(linker_load_file, link_elf_load_file), 126 KOBJMETHOD(linker_link_preload, link_elf_link_preload), 127 KOBJMETHOD(linker_link_preload_finish, link_elf_link_preload_finish), 128 KOBJMETHOD(linker_lookup_set, link_elf_lookup_set), 129 KOBJMETHOD(linker_each_function_name, link_elf_each_function_name), 130 { 0, 0 } 131 }; 132 133 static struct linker_class link_elf_class = { 134 #if ELF_TARG_CLASS == ELFCLASS32 135 "elf32", 136 #else 137 "elf64", 138 #endif 139 link_elf_methods, sizeof(struct elf_file) 140 }; 141 142 static int parse_dynamic(elf_file_t ef); 143 static int relocate_file(elf_file_t ef); 144 static int link_elf_preload_parse_symbols(elf_file_t ef); 145 146 #ifdef DDB 147 static void r_debug_state(struct r_debug *dummy_one, 148 struct link_map *dummy_two); 149 150 /* 151 * A list of loaded modules for GDB to use for loading symbols. 152 */ 153 struct r_debug r_debug; 154 155 #define GDB_STATE(s) r_debug.r_state = s; r_debug_state(NULL, NULL); 156 157 /* 158 * Function for the debugger to set a breakpoint on to gain control. 159 */ 160 void 161 r_debug_state(struct r_debug *dummy_one __unused, 162 struct link_map *dummy_two __unused) 163 { 164 } 165 166 #endif 167 168 #ifdef __ia64__ 169 Elf_Addr link_elf_get_gp(linker_file_t); 170 #endif 171 172 /* 173 * The kernel symbol table starts here. 174 */ 175 extern struct _dynamic _DYNAMIC; 176 177 static void 178 link_elf_init(void* arg) 179 { 180 #ifdef __ELF__ 181 Elf_Dyn *dp; 182 caddr_t modptr, baseptr, sizeptr; 183 elf_file_t ef; 184 char *modname; 185 #ifdef DDB 186 char *newfilename; 187 #endif 188 #endif 189 190 linker_add_class(&link_elf_class); 191 192 #ifdef __ELF__ 193 dp = (Elf_Dyn*) &_DYNAMIC; 194 modname = NULL; 195 modptr = preload_search_by_type("elf kernel"); 196 if (modptr) 197 modname = (char *)preload_search_info(modptr, MODINFO_NAME); 198 if (modname == NULL) 199 modname = "kernel"; 200 linker_kernel_file = linker_make_file(modname, &link_elf_class); 201 if (linker_kernel_file == NULL) 202 panic("link_elf_init: Can't create linker structures for kernel"); 203 204 ef = (elf_file_t) linker_kernel_file; 205 ef->preloaded = 1; 206 ef->address = 0; 207 #ifdef SPARSE_MAPPING 208 ef->object = 0; 209 #endif 210 ef->dynamic = dp; 211 212 if (dp) 213 parse_dynamic(ef); 214 linker_kernel_file->address = (caddr_t) KERNBASE; 215 linker_kernel_file->size = -(intptr_t)linker_kernel_file->address; 216 217 if (modptr) { 218 ef->modptr = modptr; 219 baseptr = preload_search_info(modptr, MODINFO_ADDR); 220 if (baseptr) 221 linker_kernel_file->address = *(caddr_t *)baseptr; 222 sizeptr = preload_search_info(modptr, MODINFO_SIZE); 223 if (sizeptr) 224 linker_kernel_file->size = *(size_t *)sizeptr; 225 } 226 (void)link_elf_preload_parse_symbols(ef); 227 228 #ifdef DDB 229 ef->gdb.l_addr = linker_kernel_file->address; 230 newfilename = malloc(strlen(modname) + 1, M_LINKER, M_WAITOK); 231 strcpy(newfilename, modname); 232 ef->gdb.l_name = newfilename; 233 ef->gdb.l_ld = dp; 234 ef->gdb.l_prev = 0; 235 ef->gdb.l_next = 0; 236 237 r_debug.r_map = &ef->gdb; 238 r_debug.r_brk = r_debug_state; 239 r_debug.r_state = RT_CONSISTENT; 240 241 r_debug_state(NULL, NULL); /* say hello to gdb! */ 242 #endif 243 244 #endif 245 } 246 247 SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_SECOND, link_elf_init, 0); 248 249 static int 250 link_elf_preload_parse_symbols(elf_file_t ef) 251 { 252 caddr_t pointer; 253 caddr_t ssym, esym, base; 254 caddr_t strtab; 255 int strcnt; 256 Elf_Sym* symtab; 257 int symcnt; 258 259 if (ef->modptr == NULL) 260 return 0; 261 pointer = preload_search_info(ef->modptr, MODINFO_METADATA|MODINFOMD_SSYM); 262 if (pointer == NULL) 263 return 0; 264 ssym = *(caddr_t *)pointer; 265 pointer = preload_search_info(ef->modptr, MODINFO_METADATA|MODINFOMD_ESYM); 266 if (pointer == NULL) 267 return 0; 268 esym = *(caddr_t *)pointer; 269 270 base = ssym; 271 272 symcnt = *(long *)base; 273 base += sizeof(long); 274 symtab = (Elf_Sym *)base; 275 base += roundup(symcnt, sizeof(long)); 276 277 if (base > esym || base < ssym) { 278 printf("Symbols are corrupt!\n"); 279 return EINVAL; 280 } 281 282 strcnt = *(long *)base; 283 base += sizeof(long); 284 strtab = base; 285 base += roundup(strcnt, sizeof(long)); 286 287 if (base > esym || base < ssym) { 288 printf("Symbols are corrupt!\n"); 289 return EINVAL; 290 } 291 292 ef->ddbsymtab = symtab; 293 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym); 294 ef->ddbstrtab = strtab; 295 ef->ddbstrcnt = strcnt; 296 297 return 0; 298 } 299 300 static int 301 parse_dynamic(elf_file_t ef) 302 { 303 Elf_Dyn *dp; 304 int plttype = DT_REL; 305 306 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) { 307 switch (dp->d_tag) { 308 case DT_HASH: 309 { 310 /* From src/libexec/rtld-elf/rtld.c */ 311 const Elf_Hashelt *hashtab = (const Elf_Hashelt *) 312 (ef->address + dp->d_un.d_ptr); 313 ef->nbuckets = hashtab[0]; 314 ef->nchains = hashtab[1]; 315 ef->buckets = hashtab + 2; 316 ef->chains = ef->buckets + ef->nbuckets; 317 break; 318 } 319 case DT_STRTAB: 320 ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr); 321 break; 322 case DT_STRSZ: 323 ef->strsz = dp->d_un.d_val; 324 break; 325 case DT_SYMTAB: 326 ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr); 327 break; 328 case DT_SYMENT: 329 if (dp->d_un.d_val != sizeof(Elf_Sym)) 330 return ENOEXEC; 331 break; 332 case DT_PLTGOT: 333 ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr); 334 break; 335 case DT_REL: 336 ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr); 337 break; 338 case DT_RELSZ: 339 ef->relsize = dp->d_un.d_val; 340 break; 341 case DT_RELENT: 342 if (dp->d_un.d_val != sizeof(Elf_Rel)) 343 return ENOEXEC; 344 break; 345 case DT_JMPREL: 346 ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr); 347 break; 348 case DT_PLTRELSZ: 349 ef->pltrelsize = dp->d_un.d_val; 350 break; 351 case DT_RELA: 352 ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr); 353 break; 354 case DT_RELASZ: 355 ef->relasize = dp->d_un.d_val; 356 break; 357 case DT_RELAENT: 358 if (dp->d_un.d_val != sizeof(Elf_Rela)) 359 return ENOEXEC; 360 break; 361 case DT_PLTREL: 362 plttype = dp->d_un.d_val; 363 if (plttype != DT_REL && plttype != DT_RELA) 364 return ENOEXEC; 365 break; 366 #ifdef DDB 367 case DT_DEBUG: 368 dp->d_un.d_ptr = (Elf_Addr) &r_debug; 369 break; 370 #endif 371 } 372 } 373 374 if (plttype == DT_RELA) { 375 ef->pltrela = (const Elf_Rela *) ef->pltrel; 376 ef->pltrel = NULL; 377 ef->pltrelasize = ef->pltrelsize; 378 ef->pltrelsize = 0; 379 } 380 381 ef->ddbsymtab = ef->symtab; 382 ef->ddbsymcnt = ef->nchains; 383 ef->ddbstrtab = ef->strtab; 384 ef->ddbstrcnt = ef->strsz; 385 386 return 0; 387 } 388 389 static void 390 link_elf_error(const char *s) 391 { 392 printf("kldload: %s\n", s); 393 } 394 395 #ifdef DDB 396 397 static void 398 link_elf_add_gdb(struct link_map *l) 399 { 400 struct link_map *prev; 401 402 /* 403 * Scan to the end of the list. 404 */ 405 for (prev = r_debug.r_map; prev->l_next != NULL; prev = prev->l_next) 406 ; 407 408 /* Link in the new entry. */ 409 l->l_prev = prev; 410 l->l_next = prev->l_next; 411 prev->l_next = l; 412 } 413 414 static void 415 link_elf_delete_gdb(struct link_map *l) 416 { 417 if (l->l_prev == NULL) { 418 if ((r_debug.r_map = l->l_next) != NULL) 419 l->l_next->l_prev = NULL; 420 return; 421 } 422 423 if ((l->l_prev->l_next = l->l_next) != NULL) 424 l->l_next->l_prev = l->l_prev; 425 } 426 427 #endif /* DDB */ 428 429 static int 430 link_elf_link_preload(linker_class_t cls, 431 const char* filename, linker_file_t *result) 432 { 433 caddr_t modptr, baseptr, sizeptr, dynptr; 434 char *type; 435 elf_file_t ef; 436 linker_file_t lf; 437 int error; 438 vm_offset_t dp; 439 440 /* Look to see if we have the file preloaded */ 441 modptr = preload_search_by_name(filename); 442 if (modptr == NULL) 443 return ENOENT; 444 445 type = (char *)preload_search_info(modptr, MODINFO_TYPE); 446 baseptr = preload_search_info(modptr, MODINFO_ADDR); 447 sizeptr = preload_search_info(modptr, MODINFO_SIZE); 448 dynptr = preload_search_info(modptr, MODINFO_METADATA|MODINFOMD_DYNAMIC); 449 if (type == NULL || strcmp(type, "elf module") != 0) 450 return (EFTYPE); 451 if (baseptr == NULL || sizeptr == NULL || dynptr == NULL) 452 return (EINVAL); 453 454 lf = linker_make_file(filename, &link_elf_class); 455 if (lf == NULL) { 456 return ENOMEM; 457 } 458 459 ef = (elf_file_t) lf; 460 ef->preloaded = 1; 461 ef->modptr = modptr; 462 ef->address = *(caddr_t *)baseptr; 463 #ifdef SPARSE_MAPPING 464 ef->object = 0; 465 #endif 466 dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr; 467 ef->dynamic = (Elf_Dyn *)dp; 468 lf->address = ef->address; 469 lf->size = *(size_t *)sizeptr; 470 471 error = parse_dynamic(ef); 472 if (error) { 473 linker_file_unload(lf); 474 return error; 475 } 476 *result = lf; 477 return (0); 478 } 479 480 static int 481 link_elf_link_preload_finish(linker_file_t lf) 482 { 483 elf_file_t ef; 484 int error; 485 #ifdef DDB 486 char *newfilename; 487 #endif 488 489 ef = (elf_file_t) lf; 490 #if 0 /* this will be more trouble than it's worth for now */ 491 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) { 492 if (dp->d_tag != DT_NEEDED) 493 continue; 494 modname = ef->strtab + dp->d_un.d_val; 495 error = linker_load_module(modname, lf); 496 if (error) 497 goto out; 498 } 499 #endif 500 error = relocate_file(ef); 501 if (error) 502 return error; 503 (void)link_elf_preload_parse_symbols(ef); 504 505 #ifdef DDB 506 GDB_STATE(RT_ADD); 507 ef->gdb.l_addr = lf->address; 508 newfilename = malloc(strlen(lf->filename) + 1, M_LINKER, M_WAITOK); 509 strcpy(newfilename, lf->filename); 510 ef->gdb.l_name = newfilename; 511 ef->gdb.l_ld = ef->dynamic; 512 link_elf_add_gdb(&ef->gdb); 513 GDB_STATE(RT_CONSISTENT); 514 #endif 515 516 return (0); 517 } 518 519 static int 520 link_elf_load_file(linker_class_t cls, const char* filename, 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 #ifdef DDB 548 char *newfilename; 549 #endif 550 551 GIANT_REQUIRED; 552 553 shdr = NULL; 554 lf = NULL; 555 556 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td); 557 flags = FREAD; 558 error = vn_open(&nd, &flags, 0); 559 if (error) 560 return error; 561 NDFREE(&nd, NDF_ONLY_PNBUF); 562 563 /* 564 * Read the elf header from the file. 565 */ 566 firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK); 567 if (firstpage == NULL) { 568 error = ENOMEM; 569 goto out; 570 } 571 hdr = (Elf_Ehdr *)firstpage; 572 error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0, 573 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 574 &resid, td); 575 nbytes = PAGE_SIZE - resid; 576 if (error) 577 goto out; 578 579 if (!IS_ELF(*hdr)) { 580 error = ENOEXEC; 581 goto out; 582 } 583 584 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS 585 || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) { 586 link_elf_error("Unsupported file layout"); 587 error = ENOEXEC; 588 goto out; 589 } 590 if (hdr->e_ident[EI_VERSION] != EV_CURRENT 591 || hdr->e_version != EV_CURRENT) { 592 link_elf_error("Unsupported file version"); 593 error = ENOEXEC; 594 goto out; 595 } 596 if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) { 597 link_elf_error("Unsupported file type"); 598 error = ENOEXEC; 599 goto out; 600 } 601 if (hdr->e_machine != ELF_TARG_MACH) { 602 link_elf_error("Unsupported machine"); 603 error = ENOEXEC; 604 goto out; 605 } 606 607 /* 608 * We rely on the program header being in the first page. This is 609 * not strictly required by the ABI specification, but it seems to 610 * always true in practice. And, it simplifies things considerably. 611 */ 612 if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) && 613 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) && 614 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes))) 615 link_elf_error("Unreadable program headers"); 616 617 /* 618 * Scan the program header entries, and save key information. 619 * 620 * We rely on there being exactly two load segments, text and data, 621 * in that order. 622 */ 623 phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff); 624 phlimit = phdr + hdr->e_phnum; 625 nsegs = 0; 626 phdyn = NULL; 627 phphdr = NULL; 628 while (phdr < phlimit) { 629 switch (phdr->p_type) { 630 631 case PT_LOAD: 632 if (nsegs == 2) { 633 link_elf_error("Too many sections"); 634 error = ENOEXEC; 635 goto out; 636 } 637 segs[nsegs] = phdr; 638 ++nsegs; 639 break; 640 641 case PT_PHDR: 642 phphdr = phdr; 643 break; 644 645 case PT_DYNAMIC: 646 phdyn = phdr; 647 break; 648 649 case PT_INTERP: 650 link_elf_error("Unsupported file type"); 651 error = ENOEXEC; 652 goto out; 653 } 654 655 ++phdr; 656 } 657 if (phdyn == NULL) { 658 link_elf_error("Object is not dynamically-linked"); 659 error = ENOEXEC; 660 goto out; 661 } 662 663 /* 664 * Allocate the entire address space of the object, to stake out our 665 * contiguous region, and to establish the base address for relocation. 666 */ 667 base_offset = trunc_page(segs[0]->p_offset); 668 base_vaddr = trunc_page(segs[0]->p_vaddr); 669 base_vlimit = round_page(segs[1]->p_vaddr + segs[1]->p_memsz); 670 mapsize = base_vlimit - base_vaddr; 671 672 lf = linker_make_file(filename, &link_elf_class); 673 if (!lf) { 674 error = ENOMEM; 675 goto out; 676 } 677 678 ef = (elf_file_t) lf; 679 #ifdef SPARSE_MAPPING 680 ef->object = vm_object_allocate(OBJT_DEFAULT, mapsize >> PAGE_SHIFT); 681 if (ef->object == NULL) { 682 free(ef, M_LINKER); 683 error = ENOMEM; 684 goto out; 685 } 686 vm_object_reference(ef->object); 687 ef->address = (caddr_t) vm_map_min(kernel_map); 688 error = vm_map_find(kernel_map, ef->object, 0, 689 (vm_offset_t *) &ef->address, 690 mapsize, 1, 691 VM_PROT_ALL, VM_PROT_ALL, 0); 692 if (error) { 693 vm_object_deallocate(ef->object); 694 ef->object = 0; 695 goto out; 696 } 697 #else 698 ef->address = malloc(mapsize, M_LINKER, M_WAITOK); 699 if (!ef->address) { 700 error = ENOMEM; 701 goto out; 702 } 703 #endif 704 mapbase = ef->address; 705 706 /* 707 * Read the text and data sections and zero the bss. 708 */ 709 for (i = 0; i < 2; i++) { 710 caddr_t segbase = mapbase + segs[i]->p_vaddr - base_vaddr; 711 error = vn_rdwr(UIO_READ, nd.ni_vp, 712 segbase, segs[i]->p_filesz, segs[i]->p_offset, 713 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 714 &resid, td); 715 if (error) { 716 goto out; 717 } 718 bzero(segbase + segs[i]->p_filesz, 719 segs[i]->p_memsz - segs[i]->p_filesz); 720 721 #ifdef SPARSE_MAPPING 722 /* 723 * Wire down the pages 724 */ 725 vm_map_pageable(kernel_map, 726 (vm_offset_t) segbase, 727 (vm_offset_t) segbase + segs[i]->p_memsz, 728 FALSE); 729 #endif 730 } 731 732 #ifdef GPROF 733 /* Update profiling information with the new text segment. */ 734 kmupetext((uintfptr_t)(mapbase + segs[0]->p_vaddr - base_vaddr + 735 segs[0]->p_memsz)); 736 #endif 737 738 ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr); 739 740 lf->address = ef->address; 741 lf->size = mapsize; 742 743 error = parse_dynamic(ef); 744 if (error) 745 goto out; 746 error = linker_load_dependencies(lf); 747 if (error) 748 goto out; 749 #if 0 /* this will be more trouble than it's worth for now */ 750 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) { 751 if (dp->d_tag != DT_NEEDED) 752 continue; 753 modname = ef->strtab + dp->d_un.d_val; 754 error = linker_load_module(modname, lf); 755 if (error) 756 goto out; 757 } 758 #endif 759 error = relocate_file(ef); 760 if (error) 761 goto out; 762 763 /* Try and load the symbol table if it's present. (you can strip it!) */ 764 nbytes = hdr->e_shnum * hdr->e_shentsize; 765 if (nbytes == 0 || hdr->e_shoff == 0) 766 goto nosyms; 767 shdr = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO); 768 if (shdr == NULL) { 769 error = ENOMEM; 770 goto out; 771 } 772 error = vn_rdwr(UIO_READ, nd.ni_vp, 773 (caddr_t)shdr, nbytes, hdr->e_shoff, 774 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 775 &resid, td); 776 if (error) 777 goto out; 778 symtabindex = -1; 779 symstrindex = -1; 780 for (i = 0; i < hdr->e_shnum; i++) { 781 if (shdr[i].sh_type == SHT_SYMTAB) { 782 symtabindex = i; 783 symstrindex = shdr[i].sh_link; 784 } 785 } 786 if (symtabindex < 0 || symstrindex < 0) 787 goto nosyms; 788 789 symcnt = shdr[symtabindex].sh_size; 790 ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK); 791 strcnt = shdr[symstrindex].sh_size; 792 ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK); 793 794 if (ef->symbase == NULL || ef->strbase == NULL) { 795 error = ENOMEM; 796 goto out; 797 } 798 error = vn_rdwr(UIO_READ, nd.ni_vp, 799 ef->symbase, symcnt, shdr[symtabindex].sh_offset, 800 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 801 &resid, td); 802 if (error) 803 goto out; 804 error = vn_rdwr(UIO_READ, nd.ni_vp, 805 ef->strbase, strcnt, shdr[symstrindex].sh_offset, 806 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 807 &resid, td); 808 if (error) 809 goto out; 810 811 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym); 812 ef->ddbsymtab = (const Elf_Sym *)ef->symbase; 813 ef->ddbstrcnt = strcnt; 814 ef->ddbstrtab = ef->strbase; 815 816 #ifdef DDB 817 GDB_STATE(RT_ADD); 818 ef->gdb.l_addr = lf->address; 819 newfilename = malloc(strlen(filename) + 1, M_LINKER, M_WAITOK); 820 strcpy(newfilename, filename); 821 ef->gdb.l_name = (const char *)newfilename; 822 ef->gdb.l_ld = ef->dynamic; 823 link_elf_add_gdb(&ef->gdb); 824 GDB_STATE(RT_CONSISTENT); 825 #endif 826 827 nosyms: 828 829 *result = lf; 830 831 out: 832 if (error && lf) 833 linker_file_unload(lf); 834 if (shdr) 835 free(shdr, M_LINKER); 836 if (firstpage) 837 free(firstpage, M_LINKER); 838 VOP_UNLOCK(nd.ni_vp, 0, td); 839 vn_close(nd.ni_vp, FREAD, td->td_ucred, td); 840 841 return error; 842 } 843 844 static void 845 link_elf_unload_file(linker_file_t file) 846 { 847 elf_file_t ef = (elf_file_t) file; 848 849 #ifdef DDB 850 if (ef->gdb.l_ld) { 851 GDB_STATE(RT_DELETE); 852 free((void *)(uintptr_t)ef->gdb.l_name, M_LINKER); 853 link_elf_delete_gdb(&ef->gdb); 854 GDB_STATE(RT_CONSISTENT); 855 } 856 #endif 857 858 if (ef->preloaded) { 859 link_elf_unload_preload(file); 860 return; 861 } 862 #ifdef SPARSE_MAPPING 863 if (ef->object) { 864 vm_map_remove(kernel_map, (vm_offset_t) ef->address, 865 (vm_offset_t) ef->address 866 + (ef->object->size << PAGE_SHIFT)); 867 vm_object_deallocate(ef->object); 868 } 869 #else 870 if (ef->address) 871 free(ef->address, M_LINKER); 872 #endif 873 if (ef->symbase) 874 free(ef->symbase, M_LINKER); 875 if (ef->strbase) 876 free(ef->strbase, M_LINKER); 877 } 878 879 static void 880 link_elf_unload_preload(linker_file_t file) 881 { 882 if (file->filename) 883 preload_delete_name(file->filename); 884 } 885 886 static const char * 887 symbol_name(elf_file_t ef, Elf_Word r_info) 888 { 889 const Elf_Sym *ref; 890 891 if (ELF_R_SYM(r_info)) { 892 ref = ef->symtab + ELF_R_SYM(r_info); 893 return ef->strtab + ref->st_name; 894 } else 895 return NULL; 896 } 897 898 static int 899 relocate_file(elf_file_t ef) 900 { 901 const Elf_Rel *rellim; 902 const Elf_Rel *rel; 903 const Elf_Rela *relalim; 904 const Elf_Rela *rela; 905 const char *symname; 906 907 /* Perform relocations without addend if there are any: */ 908 rel = ef->rel; 909 if (rel) { 910 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize); 911 while (rel < rellim) { 912 if (elf_reloc(&ef->lf, rel, ELF_RELOC_REL)) { 913 symname = symbol_name(ef, rel->r_info); 914 printf("link_elf: symbol %s undefined\n", symname); 915 return ENOENT; 916 } 917 rel++; 918 } 919 } 920 921 /* Perform relocations with addend if there are any: */ 922 rela = ef->rela; 923 if (rela) { 924 relalim = (const Elf_Rela *)((const char *)ef->rela + ef->relasize); 925 while (rela < relalim) { 926 if (elf_reloc(&ef->lf, rela, ELF_RELOC_RELA)) { 927 symname = symbol_name(ef, rela->r_info); 928 printf("link_elf: symbol %s undefined\n", symname); 929 return ENOENT; 930 } 931 rela++; 932 } 933 } 934 935 /* Perform PLT relocations without addend if there are any: */ 936 rel = ef->pltrel; 937 if (rel) { 938 rellim = (const Elf_Rel *)((const char *)ef->pltrel + ef->pltrelsize); 939 while (rel < rellim) { 940 if (elf_reloc(&ef->lf, rel, ELF_RELOC_REL)) { 941 symname = symbol_name(ef, rel->r_info); 942 printf("link_elf: symbol %s undefined\n", symname); 943 return ENOENT; 944 } 945 rel++; 946 } 947 } 948 949 /* Perform relocations with addend if there are any: */ 950 rela = ef->pltrela; 951 if (rela) { 952 relalim = (const Elf_Rela *)((const char *)ef->pltrela + ef->pltrelasize); 953 while (rela < relalim) { 954 if (elf_reloc(&ef->lf, rela, ELF_RELOC_RELA)) { 955 symname = symbol_name(ef, rela->r_info); 956 printf("link_elf: symbol %s undefined\n", symname); 957 return ENOENT; 958 } 959 rela++; 960 } 961 } 962 963 return 0; 964 } 965 966 /* 967 * Hash function for symbol table lookup. Don't even think about changing 968 * this. It is specified by the System V ABI. 969 */ 970 static unsigned long 971 elf_hash(const char *name) 972 { 973 const unsigned char *p = (const unsigned char *) name; 974 unsigned long h = 0; 975 unsigned long g; 976 977 while (*p != '\0') { 978 h = (h << 4) + *p++; 979 if ((g = h & 0xf0000000) != 0) 980 h ^= g >> 24; 981 h &= ~g; 982 } 983 return h; 984 } 985 986 int 987 link_elf_lookup_symbol(linker_file_t lf, const char* name, c_linker_sym_t* sym) 988 { 989 elf_file_t ef = (elf_file_t) lf; 990 unsigned long symnum; 991 const Elf_Sym* symp; 992 const char *strp; 993 unsigned long hash; 994 int i; 995 996 /* First, search hashed global symbols */ 997 hash = elf_hash(name); 998 symnum = ef->buckets[hash % ef->nbuckets]; 999 1000 while (symnum != STN_UNDEF) { 1001 if (symnum >= ef->nchains) { 1002 printf("link_elf_lookup_symbol: corrupt symbol table\n"); 1003 return ENOENT; 1004 } 1005 1006 symp = ef->symtab + symnum; 1007 if (symp->st_name == 0) { 1008 printf("link_elf_lookup_symbol: corrupt symbol table\n"); 1009 return ENOENT; 1010 } 1011 1012 strp = ef->strtab + symp->st_name; 1013 1014 if (strcmp(name, strp) == 0) { 1015 if (symp->st_shndx != SHN_UNDEF || 1016 (symp->st_value != 0 && 1017 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) { 1018 *sym = (c_linker_sym_t) symp; 1019 return 0; 1020 } else 1021 return ENOENT; 1022 } 1023 1024 symnum = ef->chains[symnum]; 1025 } 1026 1027 /* If we have not found it, look at the full table (if loaded) */ 1028 if (ef->symtab == ef->ddbsymtab) 1029 return ENOENT; 1030 1031 /* Exhaustive search */ 1032 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1033 strp = ef->ddbstrtab + symp->st_name; 1034 if (strcmp(name, strp) == 0) { 1035 if (symp->st_shndx != SHN_UNDEF || 1036 (symp->st_value != 0 && 1037 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) { 1038 *sym = (c_linker_sym_t) symp; 1039 return 0; 1040 } else 1041 return ENOENT; 1042 } 1043 } 1044 1045 return ENOENT; 1046 } 1047 1048 static int 1049 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, linker_symval_t* symval) 1050 { 1051 elf_file_t ef = (elf_file_t) lf; 1052 const Elf_Sym* es = (const Elf_Sym*) sym; 1053 1054 if (es >= ef->symtab && ((es - ef->symtab) < ef->nchains)) { 1055 symval->name = ef->strtab + es->st_name; 1056 symval->value = (caddr_t) ef->address + es->st_value; 1057 symval->size = es->st_size; 1058 return 0; 1059 } 1060 if (ef->symtab == ef->ddbsymtab) 1061 return ENOENT; 1062 if (es >= ef->ddbsymtab && ((es - ef->ddbsymtab) < ef->ddbsymcnt)) { 1063 symval->name = ef->ddbstrtab + es->st_name; 1064 symval->value = (caddr_t) ef->address + es->st_value; 1065 symval->size = es->st_size; 1066 return 0; 1067 } 1068 return ENOENT; 1069 } 1070 1071 static int 1072 link_elf_search_symbol(linker_file_t lf, caddr_t value, 1073 c_linker_sym_t* sym, long* diffp) 1074 { 1075 elf_file_t ef = (elf_file_t) lf; 1076 u_long off = (uintptr_t) (void *) value; 1077 u_long diff = off; 1078 u_long st_value; 1079 const Elf_Sym* es; 1080 const Elf_Sym* best = 0; 1081 int i; 1082 1083 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) { 1084 if (es->st_name == 0) 1085 continue; 1086 st_value = es->st_value + (uintptr_t) (void *) ef->address; 1087 if (off >= st_value) { 1088 if (off - st_value < diff) { 1089 diff = off - st_value; 1090 best = es; 1091 if (diff == 0) 1092 break; 1093 } else if (off - st_value == diff) { 1094 best = es; 1095 } 1096 } 1097 } 1098 if (best == 0) 1099 *diffp = off; 1100 else 1101 *diffp = diff; 1102 *sym = (c_linker_sym_t) best; 1103 1104 return 0; 1105 } 1106 1107 /* 1108 * Look up a linker set on an ELF system. 1109 */ 1110 static int 1111 link_elf_lookup_set(linker_file_t lf, const char *name, 1112 void ***startp, void ***stopp, int *countp) 1113 { 1114 c_linker_sym_t sym; 1115 linker_symval_t symval; 1116 char *setsym; 1117 void **start, **stop; 1118 int len, error = 0, count; 1119 1120 len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */ 1121 setsym = malloc(len, M_LINKER, M_WAITOK); 1122 if (setsym == NULL) 1123 return ENOMEM; 1124 1125 /* get address of first entry */ 1126 snprintf(setsym, len, "%s%s", "__start_set_", name); 1127 error = link_elf_lookup_symbol(lf, setsym, &sym); 1128 if (error) 1129 goto out; 1130 link_elf_symbol_values(lf, sym, &symval); 1131 if (symval.value == 0) { 1132 error = ESRCH; 1133 goto out; 1134 } 1135 start = (void **)symval.value; 1136 1137 /* get address of last entry */ 1138 snprintf(setsym, len, "%s%s", "__stop_set_", name); 1139 error = link_elf_lookup_symbol(lf, setsym, &sym); 1140 if (error) 1141 goto out; 1142 link_elf_symbol_values(lf, sym, &symval); 1143 if (symval.value == 0) { 1144 error = ESRCH; 1145 goto out; 1146 } 1147 stop = (void **)symval.value; 1148 1149 /* and the number of entries */ 1150 count = stop - start; 1151 1152 /* and copy out */ 1153 if (startp) 1154 *startp = start; 1155 if (stopp) 1156 *stopp = stop; 1157 if (countp) 1158 *countp = count; 1159 1160 out: 1161 free(setsym, M_LINKER); 1162 return error; 1163 } 1164 1165 static int 1166 link_elf_each_function_name(linker_file_t file, 1167 int (*callback)(const char *, void *), void *opaque) { 1168 elf_file_t ef = (elf_file_t)file; 1169 const Elf_Sym* symp; 1170 int i, error; 1171 1172 /* Exhaustive search */ 1173 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1174 if (symp->st_value != 0 && 1175 ELF_ST_TYPE(symp->st_info) == STT_FUNC) { 1176 error = callback(ef->ddbstrtab + symp->st_name, opaque); 1177 if (error) 1178 return (error); 1179 } 1180 } 1181 return (0); 1182 } 1183 1184 #ifdef __ia64__ 1185 /* 1186 * Each KLD has its own GP. The GP value for each load module is given by 1187 * DT_PLTGOT on ia64. We need GP to construct function descriptors, but 1188 * don't have direct access to the ELF file structure. The link_elf_get_gp() 1189 * function returns the GP given a pointer to a generic linker file struct. 1190 */ 1191 Elf_Addr 1192 link_elf_get_gp(linker_file_t lf) 1193 { 1194 elf_file_t ef = (elf_file_t)lf; 1195 return (Elf_Addr)ef->got; 1196 } 1197 #endif 1198 1199 /* 1200 * Symbol lookup function that can be used when the symbol index is known (ie 1201 * in relocations). It uses the symbol index instead of doing a fully fledged 1202 * hash table based lookup when such is valid. For example for local symbols. 1203 * This is not only more efficient, it's also more correct. It's not always 1204 * the case that the symbol can be found through the hash table. 1205 */ 1206 Elf_Addr 1207 elf_lookup(linker_file_t lf, Elf_Word symidx, int deps) 1208 { 1209 elf_file_t ef = (elf_file_t)lf; 1210 const Elf_Sym *sym; 1211 const char *symbol; 1212 1213 /* Don't even try to lookup the symbol if the index is bogus. */ 1214 if (symidx >= ef->nchains) 1215 return (0); 1216 1217 sym = ef->symtab + symidx; 1218 1219 /* 1220 * Don't do a full lookup when the symbol is local. It may even 1221 * fail because it may not be found through the hash table. 1222 */ 1223 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) { 1224 /* Force lookup failure when we have an insanity. */ 1225 if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0) 1226 return (0); 1227 return ((Elf_Addr)ef->address + sym->st_value); 1228 } 1229 1230 /* 1231 * XXX we can avoid doing a hash table based lookup for global 1232 * symbols as well. This however is not always valid, so we'll 1233 * just do it the hard way for now. Performance tweaks can 1234 * always be added. 1235 */ 1236 1237 symbol = ef->strtab + sym->st_name; 1238 1239 /* Force a lookup failure if the symbol name is bogus. */ 1240 if (*symbol == 0) 1241 return (0); 1242 1243 return ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps)); 1244 } 1245