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/kernel.h> 33 #include <sys/systm.h> 34 #include <sys/malloc.h> 35 #include <sys/proc.h> 36 #include <sys/namei.h> 37 #include <sys/fcntl.h> 38 #include <sys/vnode.h> 39 #include <sys/linker.h> 40 #include <machine/elf.h> 41 42 #include <vm/vm.h> 43 #include <vm/vm_param.h> 44 #include <sys/lock.h> 45 #ifdef SPARSE_MAPPING 46 #include <vm/vm_object.h> 47 #include <vm/vm_kern.h> 48 #include <vm/vm_extern.h> 49 #endif 50 #include <vm/pmap.h> 51 #include <vm/vm_map.h> 52 #include <link.h> 53 54 #include "linker_if.h" 55 56 typedef struct elf_file { 57 struct linker_file lf; /* Common fields */ 58 int preloaded; /* Was file pre-loaded */ 59 caddr_t address; /* Relocation address */ 60 #ifdef SPARSE_MAPPING 61 vm_object_t object; /* VM object to hold file pages */ 62 #endif 63 Elf_Dyn* dynamic; /* Symbol table etc. */ 64 Elf_Off nbuckets; /* DT_HASH info */ 65 Elf_Off nchains; 66 const Elf_Off* buckets; 67 const Elf_Off* chains; 68 caddr_t hash; 69 caddr_t strtab; /* DT_STRTAB */ 70 int strsz; /* DT_STRSZ */ 71 const Elf_Sym* symtab; /* DT_SYMTAB */ 72 Elf_Addr* got; /* DT_PLTGOT */ 73 const Elf_Rel* pltrel; /* DT_JMPREL */ 74 int pltrelsize; /* DT_PLTRELSZ */ 75 const Elf_Rela* pltrela; /* DT_JMPREL */ 76 int pltrelasize; /* DT_PLTRELSZ */ 77 const Elf_Rel* rel; /* DT_REL */ 78 int relsize; /* DT_RELSZ */ 79 const Elf_Rela* rela; /* DT_RELA */ 80 int relasize; /* DT_RELASZ */ 81 caddr_t modptr; 82 const Elf_Sym* ddbsymtab; /* The symbol table we are using */ 83 long ddbsymcnt; /* Number of symbols */ 84 caddr_t ddbstrtab; /* String table */ 85 long ddbstrcnt; /* number of bytes in string table */ 86 caddr_t symbase; /* malloc'ed symbold base */ 87 caddr_t strbase; /* malloc'ed string base */ 88 #ifdef DDB 89 struct link_map gdb; /* hooks for gdb */ 90 #endif 91 } *elf_file_t; 92 93 static int link_elf_link_preload(linker_class_t cls, 94 const char*, linker_file_t*); 95 static int link_elf_link_preload_finish(linker_file_t); 96 static int link_elf_load_file(linker_class_t, const char*, linker_file_t*); 97 static int link_elf_lookup_symbol(linker_file_t, const char*, 98 c_linker_sym_t*); 99 static int link_elf_symbol_values(linker_file_t, c_linker_sym_t, linker_symval_t*); 100 static int link_elf_search_symbol(linker_file_t, caddr_t value, 101 c_linker_sym_t* sym, long* diffp); 102 103 static void link_elf_unload_file(linker_file_t); 104 static void link_elf_unload_preload(linker_file_t); 105 106 static kobj_method_t link_elf_methods[] = { 107 KOBJMETHOD(linker_lookup_symbol, link_elf_lookup_symbol), 108 KOBJMETHOD(linker_symbol_values, link_elf_symbol_values), 109 KOBJMETHOD(linker_search_symbol, link_elf_search_symbol), 110 KOBJMETHOD(linker_unload, link_elf_unload_file), 111 KOBJMETHOD(linker_load_file, link_elf_load_file), 112 KOBJMETHOD(linker_link_preload, link_elf_link_preload), 113 KOBJMETHOD(linker_link_preload_finish, link_elf_link_preload_finish), 114 { 0, 0 } 115 }; 116 117 static struct linker_class link_elf_class = { 118 #if ELF_TARG_CLASS == ELFCLASS32 119 "elf32", 120 #else 121 "elf64", 122 #endif 123 link_elf_methods, sizeof(struct elf_file) 124 }; 125 126 static int parse_dynamic(elf_file_t ef); 127 static int relocate_file(elf_file_t ef); 128 static int link_elf_preload_parse_symbols(elf_file_t ef); 129 130 #ifdef DDB 131 132 /* 133 * A list of loaded modules for GDB to use for loading symbols. 134 */ 135 struct r_debug r_debug; 136 137 #define GDB_STATE(s) r_debug.r_state = s; r_debug_state(); 138 139 /* 140 * Function for the debugger to set a breakpoint on to gain control. 141 */ 142 void 143 r_debug_state(void) 144 { 145 } 146 147 #endif 148 149 /* 150 * The kernel symbol table starts here. 151 */ 152 extern struct _dynamic _DYNAMIC; 153 154 static void 155 link_elf_init(void* arg) 156 { 157 #ifdef __ELF__ 158 Elf_Dyn *dp; 159 caddr_t modptr, baseptr, sizeptr; 160 elf_file_t ef; 161 char *modname; 162 #endif 163 164 linker_add_class(&link_elf_class); 165 166 #ifdef __ELF__ 167 dp = (Elf_Dyn*) &_DYNAMIC; 168 if (dp) { 169 modname = NULL; 170 modptr = preload_search_by_type("elf kernel"); 171 if (modptr) 172 modname = (char *)preload_search_info(modptr, MODINFO_NAME); 173 if (modname == NULL) 174 modname = "kernel"; 175 linker_kernel_file = linker_make_file(modname, &link_elf_class); 176 if (linker_kernel_file == NULL) 177 panic("link_elf_init: Can't create linker structures for kernel"); 178 179 ef = (elf_file_t) linker_kernel_file; 180 ef->preloaded = 1; 181 ef->address = 0; 182 #ifdef SPARSE_MAPPING 183 ef->object = 0; 184 #endif 185 ef->dynamic = dp; 186 187 parse_dynamic(ef); 188 linker_kernel_file->address = (caddr_t) KERNBASE; 189 linker_kernel_file->size = -(intptr_t)linker_kernel_file->address; 190 191 if (modptr) { 192 ef->modptr = modptr; 193 baseptr = preload_search_info(modptr, MODINFO_ADDR); 194 if (baseptr) 195 linker_kernel_file->address = *(caddr_t *)baseptr; 196 sizeptr = preload_search_info(modptr, MODINFO_SIZE); 197 if (sizeptr) 198 linker_kernel_file->size = *(size_t *)sizeptr; 199 } 200 (void)link_elf_preload_parse_symbols(ef); 201 202 #ifdef DDB 203 ef->gdb.l_addr = linker_kernel_file->address; 204 ef->gdb.l_name = modname; 205 ef->gdb.l_ld = dp; 206 ef->gdb.l_prev = 0; 207 ef->gdb.l_next = 0; 208 209 r_debug.r_map = &ef->gdb; 210 r_debug.r_brk = r_debug_state; 211 r_debug.r_state = RT_CONSISTENT; 212 213 r_debug_state(); /* say hello to gdb! */ 214 #endif 215 216 } 217 #endif 218 } 219 220 SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_SECOND, link_elf_init, 0); 221 222 static int 223 link_elf_preload_parse_symbols(elf_file_t ef) 224 { 225 caddr_t pointer; 226 caddr_t ssym, esym, base; 227 caddr_t strtab; 228 int strcnt; 229 Elf_Sym* symtab; 230 int symcnt; 231 232 if (ef->modptr == NULL) 233 return 0; 234 pointer = preload_search_info(ef->modptr, MODINFO_METADATA|MODINFOMD_SSYM); 235 if (pointer == NULL) 236 return 0; 237 ssym = *(caddr_t *)pointer; 238 pointer = preload_search_info(ef->modptr, MODINFO_METADATA|MODINFOMD_ESYM); 239 if (pointer == NULL) 240 return 0; 241 esym = *(caddr_t *)pointer; 242 243 base = ssym; 244 245 symcnt = *(long *)base; 246 base += sizeof(long); 247 symtab = (Elf_Sym *)base; 248 base += roundup(symcnt, sizeof(long)); 249 250 if (base > esym || base < ssym) { 251 printf("Symbols are corrupt!\n"); 252 return EINVAL; 253 } 254 255 strcnt = *(long *)base; 256 base += sizeof(long); 257 strtab = base; 258 base += roundup(strcnt, sizeof(long)); 259 260 if (base > esym || base < ssym) { 261 printf("Symbols are corrupt!\n"); 262 return EINVAL; 263 } 264 265 ef->ddbsymtab = symtab; 266 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym); 267 ef->ddbstrtab = strtab; 268 ef->ddbstrcnt = strcnt; 269 270 return 0; 271 } 272 273 static int 274 parse_dynamic(elf_file_t ef) 275 { 276 Elf_Dyn *dp; 277 int plttype = DT_REL; 278 279 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) { 280 switch (dp->d_tag) { 281 case DT_HASH: 282 { 283 /* From src/libexec/rtld-elf/rtld.c */ 284 const Elf_Off *hashtab = (const Elf_Off *) 285 (ef->address + dp->d_un.d_ptr); 286 ef->nbuckets = hashtab[0]; 287 ef->nchains = hashtab[1]; 288 ef->buckets = hashtab + 2; 289 ef->chains = ef->buckets + ef->nbuckets; 290 break; 291 } 292 case DT_STRTAB: 293 ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr); 294 break; 295 case DT_STRSZ: 296 ef->strsz = dp->d_un.d_val; 297 break; 298 case DT_SYMTAB: 299 ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr); 300 break; 301 case DT_SYMENT: 302 if (dp->d_un.d_val != sizeof(Elf_Sym)) 303 return ENOEXEC; 304 break; 305 case DT_PLTGOT: 306 ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr); 307 break; 308 case DT_REL: 309 ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr); 310 break; 311 case DT_RELSZ: 312 ef->relsize = dp->d_un.d_val; 313 break; 314 case DT_RELENT: 315 if (dp->d_un.d_val != sizeof(Elf_Rel)) 316 return ENOEXEC; 317 break; 318 case DT_JMPREL: 319 ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr); 320 break; 321 case DT_PLTRELSZ: 322 ef->pltrelsize = dp->d_un.d_val; 323 break; 324 case DT_RELA: 325 ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr); 326 break; 327 case DT_RELASZ: 328 ef->relasize = dp->d_un.d_val; 329 break; 330 case DT_RELAENT: 331 if (dp->d_un.d_val != sizeof(Elf_Rela)) 332 return ENOEXEC; 333 break; 334 case DT_PLTREL: 335 plttype = dp->d_un.d_val; 336 if (plttype != DT_REL && plttype != DT_RELA) 337 return ENOEXEC; 338 break; 339 #ifdef DDB 340 case DT_DEBUG: 341 dp->d_un.d_ptr = (Elf_Addr) &r_debug; 342 break; 343 #endif 344 } 345 } 346 347 if (plttype == DT_RELA) { 348 ef->pltrela = (const Elf_Rela *) ef->pltrel; 349 ef->pltrel = NULL; 350 ef->pltrelasize = ef->pltrelsize; 351 ef->pltrelsize = 0; 352 } 353 354 ef->ddbsymtab = ef->symtab; 355 ef->ddbsymcnt = ef->nchains; 356 ef->ddbstrtab = ef->strtab; 357 ef->ddbstrcnt = ef->strsz; 358 359 return 0; 360 } 361 362 static void 363 link_elf_error(const char *s) 364 { 365 printf("kldload: %s\n", s); 366 } 367 368 #ifdef DDB 369 370 static void 371 link_elf_add_gdb(struct link_map *l) 372 { 373 struct link_map *prev; 374 375 /* 376 * Scan to the end of the list. 377 */ 378 for (prev = r_debug.r_map; prev->l_next != NULL; prev = prev->l_next) 379 ; 380 381 /* Link in the new entry. */ 382 l->l_prev = prev; 383 l->l_next = prev->l_next; 384 prev->l_next = l; 385 } 386 387 static void 388 link_elf_delete_gdb(struct link_map *l) 389 { 390 if (l->l_prev == NULL) { 391 if ((r_debug.r_map = l->l_next) != NULL) 392 l->l_next->l_prev = NULL; 393 return; 394 } 395 396 if ((l->l_prev->l_next = l->l_next) != NULL) 397 l->l_next->l_prev = l->l_prev; 398 } 399 400 #endif /* DDB */ 401 402 static int 403 link_elf_link_preload(linker_class_t cls, 404 const char* filename, linker_file_t *result) 405 { 406 caddr_t modptr, baseptr, sizeptr, dynptr; 407 char *type; 408 elf_file_t ef; 409 linker_file_t lf; 410 int error; 411 vm_offset_t dp; 412 413 /* Look to see if we have the file preloaded */ 414 modptr = preload_search_by_name(filename); 415 if (modptr == NULL) 416 return ENOENT; 417 418 type = (char *)preload_search_info(modptr, MODINFO_TYPE); 419 baseptr = preload_search_info(modptr, MODINFO_ADDR); 420 sizeptr = preload_search_info(modptr, MODINFO_SIZE); 421 dynptr = preload_search_info(modptr, MODINFO_METADATA|MODINFOMD_DYNAMIC); 422 if (type == NULL || strcmp(type, "elf module") != 0) 423 return (EFTYPE); 424 if (baseptr == NULL || sizeptr == NULL || dynptr == NULL) 425 return (EINVAL); 426 427 lf = linker_make_file(filename, &link_elf_class); 428 if (lf == NULL) { 429 return ENOMEM; 430 } 431 432 ef = (elf_file_t) lf; 433 ef->preloaded = 1; 434 ef->modptr = modptr; 435 ef->address = *(caddr_t *)baseptr; 436 #ifdef SPARSE_MAPPING 437 ef->object = 0; 438 #endif 439 dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr; 440 ef->dynamic = (Elf_Dyn *)dp; 441 lf->address = ef->address; 442 lf->size = *(size_t *)sizeptr; 443 444 error = parse_dynamic(ef); 445 if (error) { 446 linker_file_unload(lf); 447 return error; 448 } 449 *result = lf; 450 return (0); 451 } 452 453 static int 454 link_elf_link_preload_finish(linker_file_t lf) 455 { 456 elf_file_t ef; 457 int error; 458 459 ef = (elf_file_t) lf; 460 #if 0 /* this will be more trouble than it's worth for now */ 461 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) { 462 if (dp->d_tag != DT_NEEDED) 463 continue; 464 modname = ef->strtab + dp->d_un.d_val; 465 error = linker_load_module(modname, lf); 466 if (error) 467 goto out; 468 } 469 #endif 470 error = relocate_file(ef); 471 if (error) 472 return error; 473 (void)link_elf_preload_parse_symbols(ef); 474 475 #ifdef DDB 476 GDB_STATE(RT_ADD); 477 ef->gdb.l_addr = lf->address; 478 ef->gdb.l_name = lf->filename; 479 ef->gdb.l_ld = ef->dynamic; 480 link_elf_add_gdb(&ef->gdb); 481 GDB_STATE(RT_CONSISTENT); 482 #endif 483 484 return (0); 485 } 486 487 static int 488 link_elf_load_file(linker_class_t cls, const char* filename, linker_file_t* result) 489 { 490 struct nameidata nd; 491 struct proc* p = curproc; /* XXX */ 492 Elf_Ehdr *hdr; 493 caddr_t firstpage; 494 int nbytes, i; 495 Elf_Phdr *phdr; 496 Elf_Phdr *phlimit; 497 Elf_Phdr *segs[2]; 498 int nsegs; 499 Elf_Phdr *phdyn; 500 Elf_Phdr *phphdr; 501 caddr_t mapbase; 502 size_t mapsize; 503 Elf_Off base_offset; 504 Elf_Addr base_vaddr; 505 Elf_Addr base_vlimit; 506 int error = 0; 507 int resid, flags; 508 elf_file_t ef; 509 linker_file_t lf; 510 Elf_Shdr *shdr; 511 int symtabindex; 512 int symstrindex; 513 int symcnt; 514 int strcnt; 515 516 shdr = NULL; 517 lf = NULL; 518 519 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, p); 520 flags = FREAD; 521 error = vn_open(&nd, &flags, 0); 522 if (error) 523 return error; 524 NDFREE(&nd, NDF_ONLY_PNBUF); 525 526 /* 527 * Read the elf header from the file. 528 */ 529 firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK); 530 if (firstpage == NULL) { 531 error = ENOMEM; 532 goto out; 533 } 534 hdr = (Elf_Ehdr *)firstpage; 535 error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0, 536 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, p); 537 nbytes = PAGE_SIZE - resid; 538 if (error) 539 goto out; 540 541 if (!IS_ELF(*hdr)) { 542 error = ENOEXEC; 543 goto out; 544 } 545 546 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS 547 || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) { 548 link_elf_error("Unsupported file layout"); 549 error = ENOEXEC; 550 goto out; 551 } 552 if (hdr->e_ident[EI_VERSION] != EV_CURRENT 553 || hdr->e_version != EV_CURRENT) { 554 link_elf_error("Unsupported file version"); 555 error = ENOEXEC; 556 goto out; 557 } 558 if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) { 559 link_elf_error("Unsupported file type"); 560 error = ENOEXEC; 561 goto out; 562 } 563 if (hdr->e_machine != ELF_TARG_MACH) { 564 link_elf_error("Unsupported machine"); 565 error = ENOEXEC; 566 goto out; 567 } 568 569 /* 570 * We rely on the program header being in the first page. This is 571 * not strictly required by the ABI specification, but it seems to 572 * always true in practice. And, it simplifies things considerably. 573 */ 574 if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) && 575 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) && 576 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes))) 577 link_elf_error("Unreadable program headers"); 578 579 /* 580 * Scan the program header entries, and save key information. 581 * 582 * We rely on there being exactly two load segments, text and data, 583 * in that order. 584 */ 585 phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff); 586 phlimit = phdr + hdr->e_phnum; 587 nsegs = 0; 588 phdyn = NULL; 589 phphdr = NULL; 590 while (phdr < phlimit) { 591 switch (phdr->p_type) { 592 593 case PT_LOAD: 594 if (nsegs == 2) { 595 link_elf_error("Too many sections"); 596 error = ENOEXEC; 597 goto out; 598 } 599 segs[nsegs] = phdr; 600 ++nsegs; 601 break; 602 603 case PT_PHDR: 604 phphdr = phdr; 605 break; 606 607 case PT_DYNAMIC: 608 phdyn = phdr; 609 break; 610 } 611 612 ++phdr; 613 } 614 if (phdyn == NULL) { 615 link_elf_error("Object is not dynamically-linked"); 616 error = ENOEXEC; 617 goto out; 618 } 619 620 /* 621 * Allocate the entire address space of the object, to stake out our 622 * contiguous region, and to establish the base address for relocation. 623 */ 624 base_offset = trunc_page(segs[0]->p_offset); 625 base_vaddr = trunc_page(segs[0]->p_vaddr); 626 base_vlimit = round_page(segs[1]->p_vaddr + segs[1]->p_memsz); 627 mapsize = base_vlimit - base_vaddr; 628 629 lf = linker_make_file(filename, &link_elf_class); 630 if (!lf) { 631 error = ENOMEM; 632 goto out; 633 } 634 635 ef = (elf_file_t) lf; 636 #ifdef SPARSE_MAPPING 637 ef->object = vm_object_allocate(OBJT_DEFAULT, mapsize >> PAGE_SHIFT); 638 if (ef->object == NULL) { 639 free(ef, M_LINKER); 640 error = ENOMEM; 641 goto out; 642 } 643 vm_object_reference(ef->object); 644 ef->address = (caddr_t) vm_map_min(kernel_map); 645 error = vm_map_find(kernel_map, ef->object, 0, 646 (vm_offset_t *) &ef->address, 647 mapsize, 1, 648 VM_PROT_ALL, VM_PROT_ALL, 0); 649 if (error) { 650 vm_object_deallocate(ef->object); 651 ef->object = 0; 652 goto out; 653 } 654 #else 655 ef->address = malloc(mapsize, M_LINKER, M_WAITOK); 656 if (!ef->address) { 657 error = ENOMEM; 658 goto out; 659 } 660 #endif 661 mapbase = ef->address; 662 663 /* 664 * Read the text and data sections and zero the bss. 665 */ 666 for (i = 0; i < 2; i++) { 667 caddr_t segbase = mapbase + segs[i]->p_vaddr - base_vaddr; 668 error = vn_rdwr(UIO_READ, nd.ni_vp, 669 segbase, segs[i]->p_filesz, segs[i]->p_offset, 670 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, p); 671 if (error) { 672 goto out; 673 } 674 bzero(segbase + segs[i]->p_filesz, 675 segs[i]->p_memsz - segs[i]->p_filesz); 676 677 #ifdef SPARSE_MAPPING 678 /* 679 * Wire down the pages 680 */ 681 vm_map_pageable(kernel_map, 682 (vm_offset_t) segbase, 683 (vm_offset_t) segbase + segs[i]->p_memsz, 684 FALSE); 685 #endif 686 } 687 688 ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr); 689 690 lf->address = ef->address; 691 lf->size = mapsize; 692 693 error = parse_dynamic(ef); 694 if (error) 695 goto out; 696 error = linker_load_dependancies(lf); 697 if (error) 698 goto out; 699 #if 0 /* this will be more trouble than it's worth for now */ 700 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) { 701 if (dp->d_tag != DT_NEEDED) 702 continue; 703 modname = ef->strtab + dp->d_un.d_val; 704 error = linker_load_module(modname, lf); 705 if (error) 706 goto out; 707 } 708 #endif 709 error = relocate_file(ef); 710 if (error) 711 goto out; 712 713 /* Try and load the symbol table if it's present. (you can strip it!) */ 714 nbytes = hdr->e_shnum * hdr->e_shentsize; 715 if (nbytes == 0 || hdr->e_shoff == 0) 716 goto nosyms; 717 shdr = malloc(nbytes, M_LINKER, M_WAITOK); 718 if (shdr == NULL) { 719 error = ENOMEM; 720 goto out; 721 } 722 bzero(shdr, nbytes); 723 error = vn_rdwr(UIO_READ, nd.ni_vp, 724 (caddr_t)shdr, nbytes, hdr->e_shoff, 725 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, p); 726 if (error) 727 goto out; 728 symtabindex = -1; 729 symstrindex = -1; 730 for (i = 0; i < hdr->e_shnum; i++) { 731 if (shdr[i].sh_type == SHT_SYMTAB) { 732 symtabindex = i; 733 symstrindex = shdr[i].sh_link; 734 } 735 } 736 if (symtabindex < 0 || symstrindex < 0) 737 goto nosyms; 738 739 symcnt = shdr[symtabindex].sh_size; 740 ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK); 741 strcnt = shdr[symstrindex].sh_size; 742 ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK); 743 744 if (ef->symbase == NULL || ef->strbase == NULL) { 745 error = ENOMEM; 746 goto out; 747 } 748 error = vn_rdwr(UIO_READ, nd.ni_vp, 749 ef->symbase, symcnt, shdr[symtabindex].sh_offset, 750 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, p); 751 if (error) 752 goto out; 753 error = vn_rdwr(UIO_READ, nd.ni_vp, 754 ef->strbase, strcnt, shdr[symstrindex].sh_offset, 755 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, p); 756 if (error) 757 goto out; 758 759 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym); 760 ef->ddbsymtab = (const Elf_Sym *)ef->symbase; 761 ef->ddbstrcnt = strcnt; 762 ef->ddbstrtab = ef->strbase; 763 764 #ifdef DDB 765 GDB_STATE(RT_ADD); 766 ef->gdb.l_addr = lf->address; 767 ef->gdb.l_name = filename; 768 ef->gdb.l_ld = ef->dynamic; 769 link_elf_add_gdb(&ef->gdb); 770 GDB_STATE(RT_CONSISTENT); 771 #endif 772 773 nosyms: 774 775 *result = lf; 776 777 out: 778 if (error && lf) 779 linker_file_unload(lf); 780 if (shdr) 781 free(shdr, M_LINKER); 782 if (firstpage) 783 free(firstpage, M_LINKER); 784 VOP_UNLOCK(nd.ni_vp, 0, p); 785 vn_close(nd.ni_vp, FREAD, p->p_ucred, p); 786 787 return error; 788 } 789 790 static void 791 link_elf_unload_file(linker_file_t file) 792 { 793 elf_file_t ef = (elf_file_t) file; 794 795 #ifdef DDB 796 if (ef->gdb.l_ld) { 797 GDB_STATE(RT_DELETE); 798 link_elf_delete_gdb(&ef->gdb); 799 GDB_STATE(RT_CONSISTENT); 800 } 801 #endif 802 803 if (ef->preloaded) { 804 link_elf_unload_preload(file); 805 return; 806 } 807 #ifdef SPARSE_MAPPING 808 if (ef->object) { 809 vm_map_remove(kernel_map, (vm_offset_t) ef->address, 810 (vm_offset_t) ef->address 811 + (ef->object->size << PAGE_SHIFT)); 812 vm_object_deallocate(ef->object); 813 } 814 #else 815 if (ef->address) 816 free(ef->address, M_LINKER); 817 #endif 818 if (ef->symbase) 819 free(ef->symbase, M_LINKER); 820 if (ef->strbase) 821 free(ef->strbase, M_LINKER); 822 } 823 824 static void 825 link_elf_unload_preload(linker_file_t file) 826 { 827 if (file->filename) 828 preload_delete_name(file->filename); 829 } 830 831 static const char * 832 symbol_name(elf_file_t ef, Elf_Word r_info) 833 { 834 const Elf_Sym *ref; 835 836 if (ELF_R_SYM(r_info)) { 837 ref = ef->symtab + ELF_R_SYM(r_info); 838 return ef->strtab + ref->st_name; 839 } else 840 return NULL; 841 } 842 843 static int 844 relocate_file(elf_file_t ef) 845 { 846 const Elf_Rel *rellim; 847 const Elf_Rel *rel; 848 const Elf_Rela *relalim; 849 const Elf_Rela *rela; 850 const char *symname; 851 852 /* Perform relocations without addend if there are any: */ 853 rel = ef->rel; 854 if (rel) { 855 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize); 856 while (rel < rellim) { 857 symname = symbol_name(ef, rel->r_info); 858 if (elf_reloc(&ef->lf, rel, ELF_RELOC_REL, symname)) { 859 printf("link_elf: symbol %s undefined\n", symname); 860 return ENOENT; 861 } 862 rel++; 863 } 864 } 865 866 /* Perform relocations with addend if there are any: */ 867 rela = ef->rela; 868 if (rela) { 869 relalim = (const Elf_Rela *)((const char *)ef->rela + ef->relasize); 870 while (rela < relalim) { 871 symname = symbol_name(ef, rela->r_info); 872 if (elf_reloc(&ef->lf, rela, ELF_RELOC_RELA, symname)) { 873 printf("link_elf: symbol %s undefined\n", symname); 874 return ENOENT; 875 } 876 rela++; 877 } 878 } 879 880 /* Perform PLT relocations without addend if there are any: */ 881 rel = ef->pltrel; 882 if (rel) { 883 rellim = (const Elf_Rel *)((const char *)ef->pltrel + ef->pltrelsize); 884 while (rel < rellim) { 885 symname = symbol_name(ef, rel->r_info); 886 if (elf_reloc(&ef->lf, rel, ELF_RELOC_REL, symname)) { 887 printf("link_elf: symbol %s undefined\n", symname); 888 return ENOENT; 889 } 890 rel++; 891 } 892 } 893 894 /* Perform relocations with addend if there are any: */ 895 rela = ef->pltrela; 896 if (rela) { 897 relalim = (const Elf_Rela *)((const char *)ef->pltrela + ef->pltrelasize); 898 while (rela < relalim) { 899 symname = symbol_name(ef, rela->r_info); 900 if (elf_reloc(&ef->lf, rela, ELF_RELOC_RELA, symname)) { 901 printf("link_elf: symbol %s undefined\n", symname); 902 return ENOENT; 903 } 904 rela++; 905 } 906 } 907 908 return 0; 909 } 910 911 /* 912 * Hash function for symbol table lookup. Don't even think about changing 913 * this. It is specified by the System V ABI. 914 */ 915 static unsigned long 916 elf_hash(const char *name) 917 { 918 const unsigned char *p = (const unsigned char *) name; 919 unsigned long h = 0; 920 unsigned long g; 921 922 while (*p != '\0') { 923 h = (h << 4) + *p++; 924 if ((g = h & 0xf0000000) != 0) 925 h ^= g >> 24; 926 h &= ~g; 927 } 928 return h; 929 } 930 931 int 932 link_elf_lookup_symbol(linker_file_t lf, const char* name, c_linker_sym_t* sym) 933 { 934 elf_file_t ef = (elf_file_t) lf; 935 unsigned long symnum; 936 const Elf_Sym* symp; 937 const char *strp; 938 unsigned long hash; 939 int i; 940 941 /* First, search hashed global symbols */ 942 hash = elf_hash(name); 943 symnum = ef->buckets[hash % ef->nbuckets]; 944 945 while (symnum != STN_UNDEF) { 946 if (symnum >= ef->nchains) { 947 printf("link_elf_lookup_symbol: corrupt symbol table\n"); 948 return ENOENT; 949 } 950 951 symp = ef->symtab + symnum; 952 if (symp->st_name == 0) { 953 printf("link_elf_lookup_symbol: corrupt symbol table\n"); 954 return ENOENT; 955 } 956 957 strp = ef->strtab + symp->st_name; 958 959 if (strcmp(name, strp) == 0) { 960 if (symp->st_shndx != SHN_UNDEF || 961 (symp->st_value != 0 && 962 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) { 963 *sym = (c_linker_sym_t) symp; 964 return 0; 965 } else 966 return ENOENT; 967 } 968 969 symnum = ef->chains[symnum]; 970 } 971 972 /* If we have not found it, look at the full table (if loaded) */ 973 if (ef->symtab == ef->ddbsymtab) 974 return ENOENT; 975 976 /* Exhaustive search */ 977 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 978 strp = ef->ddbstrtab + symp->st_name; 979 if (strcmp(name, strp) == 0) { 980 if (symp->st_shndx != SHN_UNDEF || 981 (symp->st_value != 0 && 982 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) { 983 *sym = (c_linker_sym_t) symp; 984 return 0; 985 } else 986 return ENOENT; 987 } 988 } 989 990 return ENOENT; 991 } 992 993 static int 994 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, linker_symval_t* symval) 995 { 996 elf_file_t ef = (elf_file_t) lf; 997 const Elf_Sym* es = (const Elf_Sym*) sym; 998 999 if (es >= ef->symtab && ((es - ef->symtab) < ef->nchains)) { 1000 symval->name = ef->strtab + es->st_name; 1001 symval->value = (caddr_t) ef->address + es->st_value; 1002 symval->size = es->st_size; 1003 return 0; 1004 } 1005 if (ef->symtab == ef->ddbsymtab) 1006 return ENOENT; 1007 if (es >= ef->ddbsymtab && ((es - ef->ddbsymtab) < ef->ddbsymcnt)) { 1008 symval->name = ef->ddbstrtab + es->st_name; 1009 symval->value = (caddr_t) ef->address + es->st_value; 1010 symval->size = es->st_size; 1011 return 0; 1012 } 1013 return ENOENT; 1014 } 1015 1016 static int 1017 link_elf_search_symbol(linker_file_t lf, caddr_t value, 1018 c_linker_sym_t* sym, long* diffp) 1019 { 1020 elf_file_t ef = (elf_file_t) lf; 1021 u_long off = (uintptr_t) (void *) value; 1022 u_long diff = off; 1023 u_long st_value; 1024 const Elf_Sym* es; 1025 const Elf_Sym* best = 0; 1026 int i; 1027 1028 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) { 1029 if (es->st_name == 0) 1030 continue; 1031 st_value = es->st_value + (uintptr_t) (void *) ef->address; 1032 if (off >= st_value) { 1033 if (off - st_value < diff) { 1034 diff = off - st_value; 1035 best = es; 1036 if (diff == 0) 1037 break; 1038 } else if (off - st_value == diff) { 1039 best = es; 1040 } 1041 } 1042 } 1043 if (best == 0) 1044 *diffp = off; 1045 else 1046 *diffp = diff; 1047 *sym = (c_linker_sym_t) best; 1048 1049 return 0; 1050 } 1051