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