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; 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 error = vn_open(&nd, FREAD, 0); 521 if (error) 522 return error; 523 NDFREE(&nd, NDF_ONLY_PNBUF); 524 525 /* 526 * Read the elf header from the file. 527 */ 528 firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK); 529 if (firstpage == NULL) { 530 error = ENOMEM; 531 goto out; 532 } 533 hdr = (Elf_Ehdr *)firstpage; 534 error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0, 535 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, p); 536 nbytes = PAGE_SIZE - resid; 537 if (error) 538 goto out; 539 540 if (!IS_ELF(*hdr)) { 541 error = ENOEXEC; 542 goto out; 543 } 544 545 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS 546 || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) { 547 link_elf_error("Unsupported file layout"); 548 error = ENOEXEC; 549 goto out; 550 } 551 if (hdr->e_ident[EI_VERSION] != EV_CURRENT 552 || hdr->e_version != EV_CURRENT) { 553 link_elf_error("Unsupported file version"); 554 error = ENOEXEC; 555 goto out; 556 } 557 if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) { 558 link_elf_error("Unsupported file type"); 559 error = ENOEXEC; 560 goto out; 561 } 562 if (hdr->e_machine != ELF_TARG_MACH) { 563 link_elf_error("Unsupported machine"); 564 error = ENOEXEC; 565 goto out; 566 } 567 568 /* 569 * We rely on the program header being in the first page. This is 570 * not strictly required by the ABI specification, but it seems to 571 * always true in practice. And, it simplifies things considerably. 572 */ 573 if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) && 574 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) && 575 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes))) 576 link_elf_error("Unreadable program headers"); 577 578 /* 579 * Scan the program header entries, and save key information. 580 * 581 * We rely on there being exactly two load segments, text and data, 582 * in that order. 583 */ 584 phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff); 585 phlimit = phdr + hdr->e_phnum; 586 nsegs = 0; 587 phdyn = NULL; 588 phphdr = NULL; 589 while (phdr < phlimit) { 590 switch (phdr->p_type) { 591 592 case PT_LOAD: 593 if (nsegs == 2) { 594 link_elf_error("Too many sections"); 595 error = ENOEXEC; 596 goto out; 597 } 598 segs[nsegs] = phdr; 599 ++nsegs; 600 break; 601 602 case PT_PHDR: 603 phphdr = phdr; 604 break; 605 606 case PT_DYNAMIC: 607 phdyn = phdr; 608 break; 609 } 610 611 ++phdr; 612 } 613 if (phdyn == NULL) { 614 link_elf_error("Object is not dynamically-linked"); 615 error = ENOEXEC; 616 goto out; 617 } 618 619 /* 620 * Allocate the entire address space of the object, to stake out our 621 * contiguous region, and to establish the base address for relocation. 622 */ 623 base_offset = trunc_page(segs[0]->p_offset); 624 base_vaddr = trunc_page(segs[0]->p_vaddr); 625 base_vlimit = round_page(segs[1]->p_vaddr + segs[1]->p_memsz); 626 mapsize = base_vlimit - base_vaddr; 627 628 lf = linker_make_file(filename, &link_elf_class); 629 if (!lf) { 630 error = ENOMEM; 631 goto out; 632 } 633 634 ef = (elf_file_t) lf; 635 #ifdef SPARSE_MAPPING 636 ef->object = vm_object_allocate(OBJT_DEFAULT, mapsize >> PAGE_SHIFT); 637 if (ef->object == NULL) { 638 free(ef, M_LINKER); 639 error = ENOMEM; 640 goto out; 641 } 642 vm_object_reference(ef->object); 643 ef->address = (caddr_t) vm_map_min(kernel_map); 644 error = vm_map_find(kernel_map, ef->object, 0, 645 (vm_offset_t *) &ef->address, 646 mapsize, 1, 647 VM_PROT_ALL, VM_PROT_ALL, 0); 648 if (error) { 649 vm_object_deallocate(ef->object); 650 ef->object = 0; 651 goto out; 652 } 653 #else 654 ef->address = malloc(mapsize, M_LINKER, M_WAITOK); 655 if (!ef->address) { 656 error = ENOMEM; 657 goto out; 658 } 659 #endif 660 mapbase = ef->address; 661 662 /* 663 * Read the text and data sections and zero the bss. 664 */ 665 for (i = 0; i < 2; i++) { 666 caddr_t segbase = mapbase + segs[i]->p_vaddr - base_vaddr; 667 error = vn_rdwr(UIO_READ, nd.ni_vp, 668 segbase, segs[i]->p_filesz, segs[i]->p_offset, 669 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, p); 670 if (error) { 671 goto out; 672 } 673 bzero(segbase + segs[i]->p_filesz, 674 segs[i]->p_memsz - segs[i]->p_filesz); 675 676 #ifdef SPARSE_MAPPING 677 /* 678 * Wire down the pages 679 */ 680 vm_map_pageable(kernel_map, 681 (vm_offset_t) segbase, 682 (vm_offset_t) segbase + segs[i]->p_memsz, 683 FALSE); 684 #endif 685 } 686 687 ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr); 688 689 lf->address = ef->address; 690 lf->size = mapsize; 691 692 error = parse_dynamic(ef); 693 if (error) 694 goto out; 695 error = linker_load_dependancies(lf); 696 if (error) 697 goto out; 698 #if 0 /* this will be more trouble than it's worth for now */ 699 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) { 700 if (dp->d_tag != DT_NEEDED) 701 continue; 702 modname = ef->strtab + dp->d_un.d_val; 703 error = linker_load_module(modname, lf); 704 if (error) 705 goto out; 706 } 707 #endif 708 error = relocate_file(ef); 709 if (error) 710 goto out; 711 712 /* Try and load the symbol table if it's present. (you can strip it!) */ 713 nbytes = hdr->e_shnum * hdr->e_shentsize; 714 if (nbytes == 0 || hdr->e_shoff == 0) 715 goto nosyms; 716 shdr = malloc(nbytes, M_LINKER, M_WAITOK); 717 if (shdr == NULL) { 718 error = ENOMEM; 719 goto out; 720 } 721 bzero(shdr, nbytes); 722 error = vn_rdwr(UIO_READ, nd.ni_vp, 723 (caddr_t)shdr, nbytes, hdr->e_shoff, 724 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, p); 725 if (error) 726 goto out; 727 symtabindex = -1; 728 symstrindex = -1; 729 for (i = 0; i < hdr->e_shnum; i++) { 730 if (shdr[i].sh_type == SHT_SYMTAB) { 731 symtabindex = i; 732 symstrindex = shdr[i].sh_link; 733 } 734 } 735 if (symtabindex < 0 || symstrindex < 0) 736 goto nosyms; 737 738 symcnt = shdr[symtabindex].sh_size; 739 ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK); 740 strcnt = shdr[symstrindex].sh_size; 741 ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK); 742 743 if (ef->symbase == NULL || ef->strbase == NULL) { 744 error = ENOMEM; 745 goto out; 746 } 747 error = vn_rdwr(UIO_READ, nd.ni_vp, 748 ef->symbase, symcnt, shdr[symtabindex].sh_offset, 749 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, p); 750 if (error) 751 goto out; 752 error = vn_rdwr(UIO_READ, nd.ni_vp, 753 ef->strbase, strcnt, shdr[symstrindex].sh_offset, 754 UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, p); 755 if (error) 756 goto out; 757 758 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym); 759 ef->ddbsymtab = (const Elf_Sym *)ef->symbase; 760 ef->ddbstrcnt = strcnt; 761 ef->ddbstrtab = ef->strbase; 762 763 #ifdef DDB 764 GDB_STATE(RT_ADD); 765 ef->gdb.l_addr = lf->address; 766 ef->gdb.l_name = filename; 767 ef->gdb.l_ld = ef->dynamic; 768 link_elf_add_gdb(&ef->gdb); 769 GDB_STATE(RT_CONSISTENT); 770 #endif 771 772 nosyms: 773 774 *result = lf; 775 776 out: 777 if (error && lf) 778 linker_file_unload(lf); 779 if (shdr) 780 free(shdr, M_LINKER); 781 if (firstpage) 782 free(firstpage, M_LINKER); 783 VOP_UNLOCK(nd.ni_vp, 0, p); 784 vn_close(nd.ni_vp, FREAD, p->p_ucred, p); 785 786 return error; 787 } 788 789 static void 790 link_elf_unload_file(linker_file_t file) 791 { 792 elf_file_t ef = (elf_file_t) file; 793 794 #ifdef DDB 795 if (ef->gdb.l_ld) { 796 GDB_STATE(RT_DELETE); 797 link_elf_delete_gdb(&ef->gdb); 798 GDB_STATE(RT_CONSISTENT); 799 } 800 #endif 801 802 if (ef->preloaded) { 803 link_elf_unload_preload(file); 804 return; 805 } 806 #ifdef SPARSE_MAPPING 807 if (ef->object) { 808 vm_map_remove(kernel_map, (vm_offset_t) ef->address, 809 (vm_offset_t) ef->address 810 + (ef->object->size << PAGE_SHIFT)); 811 vm_object_deallocate(ef->object); 812 } 813 #else 814 if (ef->address) 815 free(ef->address, M_LINKER); 816 #endif 817 if (ef->symbase) 818 free(ef->symbase, M_LINKER); 819 if (ef->strbase) 820 free(ef->strbase, M_LINKER); 821 } 822 823 static void 824 link_elf_unload_preload(linker_file_t file) 825 { 826 if (file->filename) 827 preload_delete_name(file->filename); 828 } 829 830 static const char * 831 symbol_name(elf_file_t ef, Elf_Word r_info) 832 { 833 const Elf_Sym *ref; 834 835 if (ELF_R_SYM(r_info)) { 836 ref = ef->symtab + ELF_R_SYM(r_info); 837 return ef->strtab + ref->st_name; 838 } else 839 return NULL; 840 } 841 842 static int 843 relocate_file(elf_file_t ef) 844 { 845 const Elf_Rel *rellim; 846 const Elf_Rel *rel; 847 const Elf_Rela *relalim; 848 const Elf_Rela *rela; 849 const char *symname; 850 851 /* Perform relocations without addend if there are any: */ 852 rel = ef->rel; 853 if (rel) { 854 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize); 855 while (rel < rellim) { 856 symname = symbol_name(ef, rel->r_info); 857 if (elf_reloc(&ef->lf, rel, ELF_RELOC_REL, symname)) { 858 printf("link_elf: symbol %s undefined\n", symname); 859 return ENOENT; 860 } 861 rel++; 862 } 863 } 864 865 /* Perform relocations with addend if there are any: */ 866 rela = ef->rela; 867 if (rela) { 868 relalim = (const Elf_Rela *)((const char *)ef->rela + ef->relasize); 869 while (rela < relalim) { 870 symname = symbol_name(ef, rela->r_info); 871 if (elf_reloc(&ef->lf, rela, ELF_RELOC_RELA, symname)) { 872 printf("link_elf: symbol %s undefined\n", symname); 873 return ENOENT; 874 } 875 rela++; 876 } 877 } 878 879 /* Perform PLT relocations without addend if there are any: */ 880 rel = ef->pltrel; 881 if (rel) { 882 rellim = (const Elf_Rel *)((const char *)ef->pltrel + ef->pltrelsize); 883 while (rel < rellim) { 884 symname = symbol_name(ef, rel->r_info); 885 if (elf_reloc(&ef->lf, rel, ELF_RELOC_REL, symname)) { 886 printf("link_elf: symbol %s undefined\n", symname); 887 return ENOENT; 888 } 889 rel++; 890 } 891 } 892 893 /* Perform relocations with addend if there are any: */ 894 rela = ef->pltrela; 895 if (rela) { 896 relalim = (const Elf_Rela *)((const char *)ef->pltrela + ef->pltrelasize); 897 while (rela < relalim) { 898 symname = symbol_name(ef, rela->r_info); 899 if (elf_reloc(&ef->lf, rela, ELF_RELOC_RELA, symname)) { 900 printf("link_elf: symbol %s undefined\n", symname); 901 return ENOENT; 902 } 903 rela++; 904 } 905 } 906 907 return 0; 908 } 909 910 /* 911 * Hash function for symbol table lookup. Don't even think about changing 912 * this. It is specified by the System V ABI. 913 */ 914 static unsigned long 915 elf_hash(const char *name) 916 { 917 const unsigned char *p = (const unsigned char *) name; 918 unsigned long h = 0; 919 unsigned long g; 920 921 while (*p != '\0') { 922 h = (h << 4) + *p++; 923 if ((g = h & 0xf0000000) != 0) 924 h ^= g >> 24; 925 h &= ~g; 926 } 927 return h; 928 } 929 930 int 931 link_elf_lookup_symbol(linker_file_t lf, const char* name, c_linker_sym_t* sym) 932 { 933 elf_file_t ef = (elf_file_t) lf; 934 unsigned long symnum; 935 const Elf_Sym* symp; 936 const char *strp; 937 unsigned long hash; 938 int i; 939 940 /* First, search hashed global symbols */ 941 hash = elf_hash(name); 942 symnum = ef->buckets[hash % ef->nbuckets]; 943 944 while (symnum != STN_UNDEF) { 945 if (symnum >= ef->nchains) { 946 printf("link_elf_lookup_symbol: corrupt symbol table\n"); 947 return ENOENT; 948 } 949 950 symp = ef->symtab + symnum; 951 if (symp->st_name == 0) { 952 printf("link_elf_lookup_symbol: corrupt symbol table\n"); 953 return ENOENT; 954 } 955 956 strp = ef->strtab + symp->st_name; 957 958 if (strcmp(name, strp) == 0) { 959 if (symp->st_shndx != SHN_UNDEF || 960 (symp->st_value != 0 && 961 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) { 962 *sym = (c_linker_sym_t) symp; 963 return 0; 964 } else 965 return ENOENT; 966 } 967 968 symnum = ef->chains[symnum]; 969 } 970 971 /* If we have not found it, look at the full table (if loaded) */ 972 if (ef->symtab == ef->ddbsymtab) 973 return ENOENT; 974 975 /* Exhaustive search */ 976 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 977 strp = ef->ddbstrtab + symp->st_name; 978 if (strcmp(name, strp) == 0) { 979 if (symp->st_shndx != SHN_UNDEF || 980 (symp->st_value != 0 && 981 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) { 982 *sym = (c_linker_sym_t) symp; 983 return 0; 984 } else 985 return ENOENT; 986 } 987 } 988 989 return ENOENT; 990 } 991 992 static int 993 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, linker_symval_t* symval) 994 { 995 elf_file_t ef = (elf_file_t) lf; 996 const Elf_Sym* es = (const Elf_Sym*) sym; 997 998 if (es >= ef->symtab && ((es - ef->symtab) < ef->nchains)) { 999 symval->name = ef->strtab + es->st_name; 1000 symval->value = (caddr_t) ef->address + es->st_value; 1001 symval->size = es->st_size; 1002 return 0; 1003 } 1004 if (ef->symtab == ef->ddbsymtab) 1005 return ENOENT; 1006 if (es >= ef->ddbsymtab && ((es - ef->ddbsymtab) < ef->ddbsymcnt)) { 1007 symval->name = ef->ddbstrtab + es->st_name; 1008 symval->value = (caddr_t) ef->address + es->st_value; 1009 symval->size = es->st_size; 1010 return 0; 1011 } 1012 return ENOENT; 1013 } 1014 1015 static int 1016 link_elf_search_symbol(linker_file_t lf, caddr_t value, 1017 c_linker_sym_t* sym, long* diffp) 1018 { 1019 elf_file_t ef = (elf_file_t) lf; 1020 u_long off = (uintptr_t) (void *) value; 1021 u_long diff = off; 1022 u_long st_value; 1023 const Elf_Sym* es; 1024 const Elf_Sym* best = 0; 1025 int i; 1026 1027 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) { 1028 if (es->st_name == 0) 1029 continue; 1030 st_value = es->st_value + (uintptr_t) (void *) ef->address; 1031 if (off >= st_value) { 1032 if (off - st_value < diff) { 1033 diff = off - st_value; 1034 best = es; 1035 if (diff == 0) 1036 break; 1037 } else if (off - st_value == diff) { 1038 best = es; 1039 } 1040 } 1041 } 1042 if (best == 0) 1043 *diffp = off; 1044 else 1045 *diffp = diff; 1046 *sym = (c_linker_sym_t) best; 1047 1048 return 0; 1049 } 1050