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 struct proc* p = td->td_proc; /* XXX */ 521 Elf_Ehdr *hdr; 522 caddr_t firstpage; 523 int nbytes, i; 524 Elf_Phdr *phdr; 525 Elf_Phdr *phlimit; 526 Elf_Phdr *segs[2]; 527 int nsegs; 528 Elf_Phdr *phdyn; 529 Elf_Phdr *phphdr; 530 caddr_t mapbase; 531 size_t mapsize; 532 Elf_Off base_offset; 533 Elf_Addr base_vaddr; 534 Elf_Addr base_vlimit; 535 int error = 0; 536 int resid, flags; 537 elf_file_t ef; 538 linker_file_t lf; 539 Elf_Shdr *shdr; 540 int symtabindex; 541 int symstrindex; 542 int symcnt; 543 int strcnt; 544 #ifdef DDB 545 char *newfilename; 546 #endif 547 548 GIANT_REQUIRED; 549 550 shdr = NULL; 551 lf = NULL; 552 553 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td); 554 flags = FREAD; 555 error = vn_open(&nd, &flags, 0); 556 if (error) 557 return error; 558 NDFREE(&nd, NDF_ONLY_PNBUF); 559 560 /* 561 * Read the elf header from the file. 562 */ 563 firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK); 564 if (firstpage == NULL) { 565 error = ENOMEM; 566 goto out; 567 } 568 hdr = (Elf_Ehdr *)firstpage; 569 error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0, 570 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, td); 571 nbytes = PAGE_SIZE - resid; 572 if (error) 573 goto out; 574 575 if (!IS_ELF(*hdr)) { 576 error = ENOEXEC; 577 goto out; 578 } 579 580 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS 581 || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) { 582 link_elf_error("Unsupported file layout"); 583 error = ENOEXEC; 584 goto out; 585 } 586 if (hdr->e_ident[EI_VERSION] != EV_CURRENT 587 || hdr->e_version != EV_CURRENT) { 588 link_elf_error("Unsupported file version"); 589 error = ENOEXEC; 590 goto out; 591 } 592 if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) { 593 link_elf_error("Unsupported file type"); 594 error = ENOEXEC; 595 goto out; 596 } 597 if (hdr->e_machine != ELF_TARG_MACH) { 598 link_elf_error("Unsupported machine"); 599 error = ENOEXEC; 600 goto out; 601 } 602 603 /* 604 * We rely on the program header being in the first page. This is 605 * not strictly required by the ABI specification, but it seems to 606 * always true in practice. And, it simplifies things considerably. 607 */ 608 if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) && 609 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) && 610 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes))) 611 link_elf_error("Unreadable program headers"); 612 613 /* 614 * Scan the program header entries, and save key information. 615 * 616 * We rely on there being exactly two load segments, text and data, 617 * in that order. 618 */ 619 phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff); 620 phlimit = phdr + hdr->e_phnum; 621 nsegs = 0; 622 phdyn = NULL; 623 phphdr = NULL; 624 while (phdr < phlimit) { 625 switch (phdr->p_type) { 626 627 case PT_LOAD: 628 if (nsegs == 2) { 629 link_elf_error("Too many sections"); 630 error = ENOEXEC; 631 goto out; 632 } 633 segs[nsegs] = phdr; 634 ++nsegs; 635 break; 636 637 case PT_PHDR: 638 phphdr = phdr; 639 break; 640 641 case PT_DYNAMIC: 642 phdyn = phdr; 643 break; 644 645 case PT_INTERP: 646 link_elf_error("Unsupported file type"); 647 error = ENOEXEC; 648 goto out; 649 } 650 651 ++phdr; 652 } 653 if (phdyn == NULL) { 654 link_elf_error("Object is not dynamically-linked"); 655 error = ENOEXEC; 656 goto out; 657 } 658 659 /* 660 * Allocate the entire address space of the object, to stake out our 661 * contiguous region, and to establish the base address for relocation. 662 */ 663 base_offset = trunc_page(segs[0]->p_offset); 664 base_vaddr = trunc_page(segs[0]->p_vaddr); 665 base_vlimit = round_page(segs[1]->p_vaddr + segs[1]->p_memsz); 666 mapsize = base_vlimit - base_vaddr; 667 668 lf = linker_make_file(filename, &link_elf_class); 669 if (!lf) { 670 error = ENOMEM; 671 goto out; 672 } 673 674 ef = (elf_file_t) lf; 675 #ifdef SPARSE_MAPPING 676 ef->object = vm_object_allocate(OBJT_DEFAULT, mapsize >> PAGE_SHIFT); 677 if (ef->object == NULL) { 678 free(ef, M_LINKER); 679 error = ENOMEM; 680 goto out; 681 } 682 vm_object_reference(ef->object); 683 ef->address = (caddr_t) vm_map_min(kernel_map); 684 error = vm_map_find(kernel_map, ef->object, 0, 685 (vm_offset_t *) &ef->address, 686 mapsize, 1, 687 VM_PROT_ALL, VM_PROT_ALL, 0); 688 if (error) { 689 vm_object_deallocate(ef->object); 690 ef->object = 0; 691 goto out; 692 } 693 #else 694 ef->address = malloc(mapsize, M_LINKER, M_WAITOK); 695 if (!ef->address) { 696 error = ENOMEM; 697 goto out; 698 } 699 #endif 700 mapbase = ef->address; 701 702 /* 703 * Read the text and data sections and zero the bss. 704 */ 705 for (i = 0; i < 2; i++) { 706 caddr_t segbase = mapbase + segs[i]->p_vaddr - base_vaddr; 707 error = vn_rdwr(UIO_READ, nd.ni_vp, 708 segbase, segs[i]->p_filesz, segs[i]->p_offset, 709 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, td); 710 if (error) { 711 goto out; 712 } 713 bzero(segbase + segs[i]->p_filesz, 714 segs[i]->p_memsz - segs[i]->p_filesz); 715 716 #ifdef SPARSE_MAPPING 717 /* 718 * Wire down the pages 719 */ 720 vm_map_pageable(kernel_map, 721 (vm_offset_t) segbase, 722 (vm_offset_t) segbase + segs[i]->p_memsz, 723 FALSE); 724 #endif 725 } 726 727 #ifdef GPROF 728 /* Update profiling information with the new text segment. */ 729 kmupetext((uintfptr_t)(mapbase + segs[0]->p_vaddr - base_vaddr + 730 segs[0]->p_memsz)); 731 #endif 732 733 ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr); 734 735 lf->address = ef->address; 736 lf->size = mapsize; 737 738 error = parse_dynamic(ef); 739 if (error) 740 goto out; 741 error = linker_load_dependencies(lf); 742 if (error) 743 goto out; 744 #if 0 /* this will be more trouble than it's worth for now */ 745 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) { 746 if (dp->d_tag != DT_NEEDED) 747 continue; 748 modname = ef->strtab + dp->d_un.d_val; 749 error = linker_load_module(modname, lf); 750 if (error) 751 goto out; 752 } 753 #endif 754 error = relocate_file(ef); 755 if (error) 756 goto out; 757 758 /* Try and load the symbol table if it's present. (you can strip it!) */ 759 nbytes = hdr->e_shnum * hdr->e_shentsize; 760 if (nbytes == 0 || hdr->e_shoff == 0) 761 goto nosyms; 762 shdr = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO); 763 if (shdr == NULL) { 764 error = ENOMEM; 765 goto out; 766 } 767 error = vn_rdwr(UIO_READ, nd.ni_vp, 768 (caddr_t)shdr, nbytes, hdr->e_shoff, 769 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, td); 770 if (error) 771 goto out; 772 symtabindex = -1; 773 symstrindex = -1; 774 for (i = 0; i < hdr->e_shnum; i++) { 775 if (shdr[i].sh_type == SHT_SYMTAB) { 776 symtabindex = i; 777 symstrindex = shdr[i].sh_link; 778 } 779 } 780 if (symtabindex < 0 || symstrindex < 0) 781 goto nosyms; 782 783 symcnt = shdr[symtabindex].sh_size; 784 ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK); 785 strcnt = shdr[symstrindex].sh_size; 786 ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK); 787 788 if (ef->symbase == NULL || ef->strbase == NULL) { 789 error = ENOMEM; 790 goto out; 791 } 792 error = vn_rdwr(UIO_READ, nd.ni_vp, 793 ef->symbase, symcnt, shdr[symtabindex].sh_offset, 794 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, td); 795 if (error) 796 goto out; 797 error = vn_rdwr(UIO_READ, nd.ni_vp, 798 ef->strbase, strcnt, shdr[symstrindex].sh_offset, 799 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &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, p->p_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 symname = symbol_name(ef, rel->r_info); 905 if (elf_reloc(&ef->lf, rel, ELF_RELOC_REL, symname)) { 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 symname = symbol_name(ef, rela->r_info); 919 if (elf_reloc(&ef->lf, rela, ELF_RELOC_RELA, symname)) { 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 symname = symbol_name(ef, rel->r_info); 933 if (elf_reloc(&ef->lf, rel, ELF_RELOC_REL, symname)) { 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 symname = symbol_name(ef, rela->r_info); 947 if (elf_reloc(&ef->lf, rela, ELF_RELOC_RELA, symname)) { 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