link_elf.c revision 241896
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 27#include <sys/cdefs.h> 28__FBSDID("$FreeBSD: head/sys/kern/link_elf.c 241896 2012-10-22 17:50:54Z kib $"); 29 30#include "opt_ddb.h" 31#include "opt_gdb.h" 32 33#include <sys/param.h> 34#include <sys/systm.h> 35#ifdef GPROF 36#include <sys/gmon.h> 37#endif 38#include <sys/kernel.h> 39#include <sys/lock.h> 40#include <sys/malloc.h> 41#include <sys/mutex.h> 42#include <sys/mount.h> 43#include <sys/pcpu.h> 44#include <sys/proc.h> 45#include <sys/namei.h> 46#include <sys/fcntl.h> 47#include <sys/vnode.h> 48#include <sys/linker.h> 49 50#include <machine/elf.h> 51 52#include <net/vnet.h> 53 54#include <security/mac/mac_framework.h> 55 56#include <vm/vm.h> 57#include <vm/vm_param.h> 58#ifdef SPARSE_MAPPING 59#include <vm/vm_object.h> 60#include <vm/vm_kern.h> 61#include <vm/vm_extern.h> 62#endif 63#include <vm/pmap.h> 64#include <vm/vm_map.h> 65 66#include <sys/link_elf.h> 67 68#ifdef DDB_CTF 69#include <net/zlib.h> 70#endif 71 72#include "linker_if.h" 73 74#define MAXSEGS 4 75 76typedef struct elf_file { 77 struct linker_file lf; /* Common fields */ 78 int preloaded; /* Was file pre-loaded */ 79 caddr_t address; /* Relocation address */ 80#ifdef SPARSE_MAPPING 81 vm_object_t object; /* VM object to hold file pages */ 82#endif 83 Elf_Dyn *dynamic; /* Symbol table etc. */ 84 Elf_Hashelt nbuckets; /* DT_HASH info */ 85 Elf_Hashelt nchains; 86 const Elf_Hashelt *buckets; 87 const Elf_Hashelt *chains; 88 caddr_t hash; 89 caddr_t strtab; /* DT_STRTAB */ 90 int strsz; /* DT_STRSZ */ 91 const Elf_Sym *symtab; /* DT_SYMTAB */ 92 Elf_Addr *got; /* DT_PLTGOT */ 93 const Elf_Rel *pltrel; /* DT_JMPREL */ 94 int pltrelsize; /* DT_PLTRELSZ */ 95 const Elf_Rela *pltrela; /* DT_JMPREL */ 96 int pltrelasize; /* DT_PLTRELSZ */ 97 const Elf_Rel *rel; /* DT_REL */ 98 int relsize; /* DT_RELSZ */ 99 const Elf_Rela *rela; /* DT_RELA */ 100 int relasize; /* DT_RELASZ */ 101 caddr_t modptr; 102 const Elf_Sym *ddbsymtab; /* The symbol table we are using */ 103 long ddbsymcnt; /* Number of symbols */ 104 caddr_t ddbstrtab; /* String table */ 105 long ddbstrcnt; /* number of bytes in string table */ 106 caddr_t symbase; /* malloc'ed symbold base */ 107 caddr_t strbase; /* malloc'ed string base */ 108 caddr_t ctftab; /* CTF table */ 109 long ctfcnt; /* number of bytes in CTF table */ 110 caddr_t ctfoff; /* CTF offset table */ 111 caddr_t typoff; /* Type offset table */ 112 long typlen; /* Number of type entries. */ 113 Elf_Addr pcpu_start; /* Pre-relocation pcpu set start. */ 114 Elf_Addr pcpu_stop; /* Pre-relocation pcpu set stop. */ 115 Elf_Addr pcpu_base; /* Relocated pcpu set address. */ 116#ifdef VIMAGE 117 Elf_Addr vnet_start; /* Pre-relocation vnet set start. */ 118 Elf_Addr vnet_stop; /* Pre-relocation vnet set stop. */ 119 Elf_Addr vnet_base; /* Relocated vnet set address. */ 120#endif 121#ifdef GDB 122 struct link_map gdb; /* hooks for gdb */ 123#endif 124} *elf_file_t; 125 126struct elf_set { 127 Elf_Addr es_start; 128 Elf_Addr es_stop; 129 Elf_Addr es_base; 130 TAILQ_ENTRY(elf_set) es_link; 131}; 132 133TAILQ_HEAD(elf_set_head, elf_set); 134 135#include <kern/kern_ctf.c> 136 137static int link_elf_link_common_finish(linker_file_t); 138static int link_elf_link_preload(linker_class_t cls, 139 const char *, linker_file_t *); 140static int link_elf_link_preload_finish(linker_file_t); 141static int link_elf_load_file(linker_class_t, const char *, 142 linker_file_t *); 143static int link_elf_lookup_symbol(linker_file_t, const char *, 144 c_linker_sym_t *); 145static int link_elf_symbol_values(linker_file_t, c_linker_sym_t, 146 linker_symval_t *); 147static int link_elf_search_symbol(linker_file_t, caddr_t, 148 c_linker_sym_t *, long *); 149 150static void link_elf_unload_file(linker_file_t); 151static void link_elf_unload_preload(linker_file_t); 152static int link_elf_lookup_set(linker_file_t, const char *, 153 void ***, void ***, int *); 154static int link_elf_each_function_name(linker_file_t, 155 int (*)(const char *, void *), void *); 156static int link_elf_each_function_nameval(linker_file_t, 157 linker_function_nameval_callback_t, void *); 158static void link_elf_reloc_local(linker_file_t); 159static long link_elf_symtab_get(linker_file_t, const Elf_Sym **); 160static long link_elf_strtab_get(linker_file_t, caddr_t *); 161static Elf_Addr elf_lookup(linker_file_t, Elf_Size, int); 162 163static kobj_method_t link_elf_methods[] = { 164 KOBJMETHOD(linker_lookup_symbol, link_elf_lookup_symbol), 165 KOBJMETHOD(linker_symbol_values, link_elf_symbol_values), 166 KOBJMETHOD(linker_search_symbol, link_elf_search_symbol), 167 KOBJMETHOD(linker_unload, link_elf_unload_file), 168 KOBJMETHOD(linker_load_file, link_elf_load_file), 169 KOBJMETHOD(linker_link_preload, link_elf_link_preload), 170 KOBJMETHOD(linker_link_preload_finish, link_elf_link_preload_finish), 171 KOBJMETHOD(linker_lookup_set, link_elf_lookup_set), 172 KOBJMETHOD(linker_each_function_name, link_elf_each_function_name), 173 KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval), 174 KOBJMETHOD(linker_ctf_get, link_elf_ctf_get), 175 KOBJMETHOD(linker_symtab_get, link_elf_symtab_get), 176 KOBJMETHOD(linker_strtab_get, link_elf_strtab_get), 177 { 0, 0 } 178}; 179 180static struct linker_class link_elf_class = { 181#if ELF_TARG_CLASS == ELFCLASS32 182 "elf32", 183#else 184 "elf64", 185#endif 186 link_elf_methods, sizeof(struct elf_file) 187}; 188 189static int parse_dynamic(elf_file_t); 190static int relocate_file(elf_file_t); 191static int link_elf_preload_parse_symbols(elf_file_t); 192 193static struct elf_set_head set_pcpu_list; 194#ifdef VIMAGE 195static struct elf_set_head set_vnet_list; 196#endif 197 198static void 199elf_set_add(struct elf_set_head *list, Elf_Addr start, Elf_Addr stop, Elf_Addr base) 200{ 201 struct elf_set *set, *iter; 202 203 set = malloc(sizeof(*set), M_LINKER, M_WAITOK); 204 set->es_start = start; 205 set->es_stop = stop; 206 set->es_base = base; 207 208 TAILQ_FOREACH(iter, list, es_link) { 209 210 KASSERT((set->es_start < iter->es_start && set->es_stop < iter->es_stop) || 211 (set->es_start > iter->es_start && set->es_stop > iter->es_stop), 212 ("linker sets intersection: to insert: 0x%jx-0x%jx; inserted: 0x%jx-0x%jx", 213 (uintmax_t)set->es_start, (uintmax_t)set->es_stop, 214 (uintmax_t)iter->es_start, (uintmax_t)iter->es_stop)); 215 216 if (iter->es_start > set->es_start) { 217 TAILQ_INSERT_BEFORE(iter, set, es_link); 218 break; 219 } 220 } 221 222 if (iter == NULL) 223 TAILQ_INSERT_TAIL(list, set, es_link); 224} 225 226static int 227elf_set_find(struct elf_set_head *list, Elf_Addr addr, Elf_Addr *start, Elf_Addr *base) 228{ 229 struct elf_set *set; 230 231 TAILQ_FOREACH(set, list, es_link) { 232 if (addr < set->es_start) 233 return (0); 234 if (addr < set->es_stop) { 235 *start = set->es_start; 236 *base = set->es_base; 237 return (1); 238 } 239 } 240 241 return (0); 242} 243 244static void 245elf_set_delete(struct elf_set_head *list, Elf_Addr start) 246{ 247 struct elf_set *set; 248 249 TAILQ_FOREACH(set, list, es_link) { 250 if (start < set->es_start) 251 break; 252 if (start == set->es_start) { 253 TAILQ_REMOVE(list, set, es_link); 254 free(set, M_LINKER); 255 return; 256 } 257 } 258 KASSERT(0, ("deleting unknown linker set (start = 0x%jx)", 259 (uintmax_t)start)); 260} 261 262#ifdef GDB 263static void r_debug_state(struct r_debug *, struct link_map *); 264 265/* 266 * A list of loaded modules for GDB to use for loading symbols. 267 */ 268struct r_debug r_debug; 269 270#define GDB_STATE(s) do { \ 271 r_debug.r_state = s; r_debug_state(NULL, NULL); \ 272} while (0) 273 274/* 275 * Function for the debugger to set a breakpoint on to gain control. 276 */ 277static void 278r_debug_state(struct r_debug *dummy_one __unused, 279 struct link_map *dummy_two __unused) 280{ 281} 282 283static void 284link_elf_add_gdb(struct link_map *l) 285{ 286 struct link_map *prev; 287 288 l->l_next = NULL; 289 290 if (r_debug.r_map == NULL) { 291 /* Add first. */ 292 l->l_prev = NULL; 293 r_debug.r_map = l; 294 } else { 295 /* Append to list. */ 296 for (prev = r_debug.r_map; 297 prev->l_next != NULL; 298 prev = prev->l_next) 299 ; 300 l->l_prev = prev; 301 prev->l_next = l; 302 } 303} 304 305static void 306link_elf_delete_gdb(struct link_map *l) 307{ 308 if (l->l_prev == NULL) { 309 /* Remove first. */ 310 if ((r_debug.r_map = l->l_next) != NULL) 311 l->l_next->l_prev = NULL; 312 } else { 313 /* Remove any but first. */ 314 if ((l->l_prev->l_next = l->l_next) != NULL) 315 l->l_next->l_prev = l->l_prev; 316 } 317} 318#endif /* GDB */ 319 320#ifdef __ia64__ 321Elf_Addr link_elf_get_gp(linker_file_t); 322#endif 323 324/* 325 * The kernel symbol table starts here. 326 */ 327extern struct _dynamic _DYNAMIC; 328 329static void 330link_elf_error(const char *filename, const char *s) 331{ 332 if (filename == NULL) 333 printf("kldload: %s\n", s); 334 else 335 printf("kldload: %s: %s\n", filename, s); 336} 337 338/* 339 * Actions performed after linking/loading both the preloaded kernel and any 340 * modules; whether preloaded or dynamicly loaded. 341 */ 342static int 343link_elf_link_common_finish(linker_file_t lf) 344{ 345#ifdef GDB 346 elf_file_t ef = (elf_file_t)lf; 347 char *newfilename; 348#endif 349 int error; 350 351 /* Notify MD code that a module is being loaded. */ 352 error = elf_cpu_load_file(lf); 353 if (error != 0) 354 return (error); 355 356#ifdef GDB 357 GDB_STATE(RT_ADD); 358 ef->gdb.l_addr = lf->address; 359 newfilename = malloc(strlen(lf->filename) + 1, M_LINKER, M_WAITOK); 360 strcpy(newfilename, lf->filename); 361 ef->gdb.l_name = newfilename; 362 ef->gdb.l_ld = ef->dynamic; 363 link_elf_add_gdb(&ef->gdb); 364 GDB_STATE(RT_CONSISTENT); 365#endif 366 367 return (0); 368} 369 370static void 371link_elf_init(void* arg) 372{ 373 Elf_Dyn *dp; 374 caddr_t modptr, baseptr, sizeptr; 375 elf_file_t ef; 376 char *modname; 377 378 linker_add_class(&link_elf_class); 379 380 dp = (Elf_Dyn *)&_DYNAMIC; 381 modname = NULL; 382 modptr = preload_search_by_type("elf" __XSTRING(__ELF_WORD_SIZE) " kernel"); 383 if (modptr == NULL) 384 modptr = preload_search_by_type("elf kernel"); 385 if (modptr != NULL) 386 modname = (char *)preload_search_info(modptr, MODINFO_NAME); 387 if (modname == NULL) 388 modname = "kernel"; 389 linker_kernel_file = linker_make_file(modname, &link_elf_class); 390 if (linker_kernel_file == NULL) 391 panic("%s: Can't create linker structures for kernel", 392 __func__); 393 394 ef = (elf_file_t) linker_kernel_file; 395 ef->preloaded = 1; 396 ef->address = 0; 397#ifdef SPARSE_MAPPING 398 ef->object = 0; 399#endif 400 ef->dynamic = dp; 401 402 if (dp != NULL) 403 parse_dynamic(ef); 404 linker_kernel_file->address = (caddr_t) KERNBASE; 405 linker_kernel_file->size = -(intptr_t)linker_kernel_file->address; 406 407 if (modptr != NULL) { 408 ef->modptr = modptr; 409 baseptr = preload_search_info(modptr, MODINFO_ADDR); 410 if (baseptr != NULL) 411 linker_kernel_file->address = *(caddr_t *)baseptr; 412 sizeptr = preload_search_info(modptr, MODINFO_SIZE); 413 if (sizeptr != NULL) 414 linker_kernel_file->size = *(size_t *)sizeptr; 415 } 416 (void)link_elf_preload_parse_symbols(ef); 417 418#ifdef GDB 419 r_debug.r_map = NULL; 420 r_debug.r_brk = r_debug_state; 421 r_debug.r_state = RT_CONSISTENT; 422#endif 423 424 (void)link_elf_link_common_finish(linker_kernel_file); 425 linker_kernel_file->flags |= LINKER_FILE_LINKED; 426 TAILQ_INIT(&set_pcpu_list); 427#ifdef VIMAGE 428 TAILQ_INIT(&set_vnet_list); 429#endif 430} 431 432SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_THIRD, link_elf_init, 0); 433 434static int 435link_elf_preload_parse_symbols(elf_file_t ef) 436{ 437 caddr_t pointer; 438 caddr_t ssym, esym, base; 439 caddr_t strtab; 440 int strcnt; 441 Elf_Sym *symtab; 442 int symcnt; 443 444 if (ef->modptr == NULL) 445 return (0); 446 pointer = preload_search_info(ef->modptr, 447 MODINFO_METADATA | MODINFOMD_SSYM); 448 if (pointer == NULL) 449 return (0); 450 ssym = *(caddr_t *)pointer; 451 pointer = preload_search_info(ef->modptr, 452 MODINFO_METADATA | MODINFOMD_ESYM); 453 if (pointer == NULL) 454 return (0); 455 esym = *(caddr_t *)pointer; 456 457 base = ssym; 458 459 symcnt = *(long *)base; 460 base += sizeof(long); 461 symtab = (Elf_Sym *)base; 462 base += roundup(symcnt, sizeof(long)); 463 464 if (base > esym || base < ssym) { 465 printf("Symbols are corrupt!\n"); 466 return (EINVAL); 467 } 468 469 strcnt = *(long *)base; 470 base += sizeof(long); 471 strtab = base; 472 base += roundup(strcnt, sizeof(long)); 473 474 if (base > esym || base < ssym) { 475 printf("Symbols are corrupt!\n"); 476 return (EINVAL); 477 } 478 479 ef->ddbsymtab = symtab; 480 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym); 481 ef->ddbstrtab = strtab; 482 ef->ddbstrcnt = strcnt; 483 484 return (0); 485} 486 487static int 488parse_dynamic(elf_file_t ef) 489{ 490 Elf_Dyn *dp; 491 int plttype = DT_REL; 492 493 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) { 494 switch (dp->d_tag) { 495 case DT_HASH: 496 { 497 /* From src/libexec/rtld-elf/rtld.c */ 498 const Elf_Hashelt *hashtab = (const Elf_Hashelt *) 499 (ef->address + dp->d_un.d_ptr); 500 ef->nbuckets = hashtab[0]; 501 ef->nchains = hashtab[1]; 502 ef->buckets = hashtab + 2; 503 ef->chains = ef->buckets + ef->nbuckets; 504 break; 505 } 506 case DT_STRTAB: 507 ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr); 508 break; 509 case DT_STRSZ: 510 ef->strsz = dp->d_un.d_val; 511 break; 512 case DT_SYMTAB: 513 ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr); 514 break; 515 case DT_SYMENT: 516 if (dp->d_un.d_val != sizeof(Elf_Sym)) 517 return (ENOEXEC); 518 break; 519 case DT_PLTGOT: 520 ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr); 521 break; 522 case DT_REL: 523 ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr); 524 break; 525 case DT_RELSZ: 526 ef->relsize = dp->d_un.d_val; 527 break; 528 case DT_RELENT: 529 if (dp->d_un.d_val != sizeof(Elf_Rel)) 530 return (ENOEXEC); 531 break; 532 case DT_JMPREL: 533 ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr); 534 break; 535 case DT_PLTRELSZ: 536 ef->pltrelsize = dp->d_un.d_val; 537 break; 538 case DT_RELA: 539 ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr); 540 break; 541 case DT_RELASZ: 542 ef->relasize = dp->d_un.d_val; 543 break; 544 case DT_RELAENT: 545 if (dp->d_un.d_val != sizeof(Elf_Rela)) 546 return (ENOEXEC); 547 break; 548 case DT_PLTREL: 549 plttype = dp->d_un.d_val; 550 if (plttype != DT_REL && plttype != DT_RELA) 551 return (ENOEXEC); 552 break; 553#ifdef GDB 554 case DT_DEBUG: 555 dp->d_un.d_ptr = (Elf_Addr)&r_debug; 556 break; 557#endif 558 } 559 } 560 561 if (plttype == DT_RELA) { 562 ef->pltrela = (const Elf_Rela *)ef->pltrel; 563 ef->pltrel = NULL; 564 ef->pltrelasize = ef->pltrelsize; 565 ef->pltrelsize = 0; 566 } 567 568 ef->ddbsymtab = ef->symtab; 569 ef->ddbsymcnt = ef->nchains; 570 ef->ddbstrtab = ef->strtab; 571 ef->ddbstrcnt = ef->strsz; 572 573 return (0); 574} 575 576static int 577parse_dpcpu(elf_file_t ef) 578{ 579 int count; 580 int error; 581 582 ef->pcpu_start = 0; 583 ef->pcpu_stop = 0; 584 error = link_elf_lookup_set(&ef->lf, "pcpu", (void ***)&ef->pcpu_start, 585 (void ***)&ef->pcpu_stop, &count); 586 /* Error just means there is no pcpu set to relocate. */ 587 if (error != 0) 588 return (0); 589 count *= sizeof(void *); 590 /* 591 * Allocate space in the primary pcpu area. Copy in our 592 * initialization from the data section and then initialize 593 * all per-cpu storage from that. 594 */ 595 ef->pcpu_base = (Elf_Addr)(uintptr_t)dpcpu_alloc(count); 596 if (ef->pcpu_base == 0) 597 return (ENOSPC); 598 memcpy((void *)ef->pcpu_base, (void *)ef->pcpu_start, count); 599 dpcpu_copy((void *)ef->pcpu_base, count); 600 elf_set_add(&set_pcpu_list, ef->pcpu_start, ef->pcpu_stop, 601 ef->pcpu_base); 602 603 return (0); 604} 605 606#ifdef VIMAGE 607static int 608parse_vnet(elf_file_t ef) 609{ 610 int count; 611 int error; 612 613 ef->vnet_start = 0; 614 ef->vnet_stop = 0; 615 error = link_elf_lookup_set(&ef->lf, "vnet", (void ***)&ef->vnet_start, 616 (void ***)&ef->vnet_stop, &count); 617 /* Error just means there is no vnet data set to relocate. */ 618 if (error != 0) 619 return (0); 620 count *= sizeof(void *); 621 /* 622 * Allocate space in the primary vnet area. Copy in our 623 * initialization from the data section and then initialize 624 * all per-vnet storage from that. 625 */ 626 ef->vnet_base = (Elf_Addr)(uintptr_t)vnet_data_alloc(count); 627 if (ef->vnet_base == 0) 628 return (ENOSPC); 629 memcpy((void *)ef->vnet_base, (void *)ef->vnet_start, count); 630 vnet_data_copy((void *)ef->vnet_base, count); 631 elf_set_add(&set_vnet_list, ef->vnet_start, ef->vnet_stop, 632 ef->vnet_base); 633 634 return (0); 635} 636#endif 637 638static int 639link_elf_link_preload(linker_class_t cls, 640 const char* filename, linker_file_t *result) 641{ 642 caddr_t modptr, baseptr, sizeptr, dynptr; 643 char *type; 644 elf_file_t ef; 645 linker_file_t lf; 646 int error; 647 vm_offset_t dp; 648 649 /* Look to see if we have the file preloaded */ 650 modptr = preload_search_by_name(filename); 651 if (modptr == NULL) 652 return (ENOENT); 653 654 type = (char *)preload_search_info(modptr, MODINFO_TYPE); 655 baseptr = preload_search_info(modptr, MODINFO_ADDR); 656 sizeptr = preload_search_info(modptr, MODINFO_SIZE); 657 dynptr = preload_search_info(modptr, 658 MODINFO_METADATA | MODINFOMD_DYNAMIC); 659 if (type == NULL || 660 (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) " module") != 0 && 661 strcmp(type, "elf module") != 0)) 662 return (EFTYPE); 663 if (baseptr == NULL || sizeptr == NULL || dynptr == NULL) 664 return (EINVAL); 665 666 lf = linker_make_file(filename, &link_elf_class); 667 if (lf == NULL) 668 return (ENOMEM); 669 670 ef = (elf_file_t) lf; 671 ef->preloaded = 1; 672 ef->modptr = modptr; 673 ef->address = *(caddr_t *)baseptr; 674#ifdef SPARSE_MAPPING 675 ef->object = 0; 676#endif 677 dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr; 678 ef->dynamic = (Elf_Dyn *)dp; 679 lf->address = ef->address; 680 lf->size = *(size_t *)sizeptr; 681 682 error = parse_dynamic(ef); 683 if (error == 0) 684 error = parse_dpcpu(ef); 685#ifdef VIMAGE 686 if (error == 0) 687 error = parse_vnet(ef); 688#endif 689 if (error != 0) { 690 linker_file_unload(lf, LINKER_UNLOAD_FORCE); 691 return (error); 692 } 693 link_elf_reloc_local(lf); 694 *result = lf; 695 return (0); 696} 697 698static int 699link_elf_link_preload_finish(linker_file_t lf) 700{ 701 elf_file_t ef; 702 int error; 703 704 ef = (elf_file_t) lf; 705#if 0 /* this will be more trouble than it's worth for now */ 706 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) { 707 if (dp->d_tag != DT_NEEDED) 708 continue; 709 modname = ef->strtab + dp->d_un.d_val; 710 error = linker_load_module(modname, lf); 711 if (error != 0) 712 goto out; 713 } 714#endif 715 error = relocate_file(ef); 716 if (error != 0) 717 return (error); 718 (void)link_elf_preload_parse_symbols(ef); 719 720 return (link_elf_link_common_finish(lf)); 721} 722 723static int 724link_elf_load_file(linker_class_t cls, const char* filename, 725 linker_file_t* result) 726{ 727 struct nameidata nd; 728 struct thread* td = curthread; /* XXX */ 729 Elf_Ehdr *hdr; 730 caddr_t firstpage; 731 int nbytes, i; 732 Elf_Phdr *phdr; 733 Elf_Phdr *phlimit; 734 Elf_Phdr *segs[MAXSEGS]; 735 int nsegs; 736 Elf_Phdr *phdyn; 737 Elf_Phdr *phphdr; 738 caddr_t mapbase; 739 size_t mapsize; 740 Elf_Off base_offset; 741 Elf_Addr base_vaddr; 742 Elf_Addr base_vlimit; 743 int error = 0; 744 ssize_t resid; 745 int flags; 746 elf_file_t ef; 747 linker_file_t lf; 748 Elf_Shdr *shdr; 749 int symtabindex; 750 int symstrindex; 751 int symcnt; 752 int strcnt; 753 754 shdr = NULL; 755 lf = NULL; 756 757 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td); 758 flags = FREAD; 759 error = vn_open(&nd, &flags, 0, NULL); 760 if (error != 0) 761 return (error); 762 NDFREE(&nd, NDF_ONLY_PNBUF); 763 if (nd.ni_vp->v_type != VREG) { 764 error = ENOEXEC; 765 firstpage = NULL; 766 goto out; 767 } 768#ifdef MAC 769 error = mac_kld_check_load(curthread->td_ucred, nd.ni_vp); 770 if (error != 0) { 771 firstpage = NULL; 772 goto out; 773 } 774#endif 775 776 /* 777 * Read the elf header from the file. 778 */ 779 firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK); 780 hdr = (Elf_Ehdr *)firstpage; 781 error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0, 782 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 783 &resid, td); 784 nbytes = PAGE_SIZE - resid; 785 if (error != 0) 786 goto out; 787 788 if (!IS_ELF(*hdr)) { 789 error = ENOEXEC; 790 goto out; 791 } 792 793 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS || 794 hdr->e_ident[EI_DATA] != ELF_TARG_DATA) { 795 link_elf_error(filename, "Unsupported file layout"); 796 error = ENOEXEC; 797 goto out; 798 } 799 if (hdr->e_ident[EI_VERSION] != EV_CURRENT || 800 hdr->e_version != EV_CURRENT) { 801 link_elf_error(filename, "Unsupported file version"); 802 error = ENOEXEC; 803 goto out; 804 } 805 if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) { 806 error = ENOSYS; 807 goto out; 808 } 809 if (hdr->e_machine != ELF_TARG_MACH) { 810 link_elf_error(filename, "Unsupported machine"); 811 error = ENOEXEC; 812 goto out; 813 } 814 815 /* 816 * We rely on the program header being in the first page. 817 * This is not strictly required by the ABI specification, but 818 * it seems to always true in practice. And, it simplifies 819 * things considerably. 820 */ 821 if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) && 822 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) && 823 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes))) 824 link_elf_error(filename, "Unreadable program headers"); 825 826 /* 827 * Scan the program header entries, and save key information. 828 * 829 * We rely on there being exactly two load segments, text and data, 830 * in that order. 831 */ 832 phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff); 833 phlimit = phdr + hdr->e_phnum; 834 nsegs = 0; 835 phdyn = NULL; 836 phphdr = NULL; 837 while (phdr < phlimit) { 838 switch (phdr->p_type) { 839 case PT_LOAD: 840 if (nsegs == MAXSEGS) { 841 link_elf_error(filename, "Too many sections"); 842 error = ENOEXEC; 843 goto out; 844 } 845 /* 846 * XXX: We just trust they come in right order ?? 847 */ 848 segs[nsegs] = phdr; 849 ++nsegs; 850 break; 851 852 case PT_PHDR: 853 phphdr = phdr; 854 break; 855 856 case PT_DYNAMIC: 857 phdyn = phdr; 858 break; 859 860 case PT_INTERP: 861 error = ENOSYS; 862 goto out; 863 } 864 865 ++phdr; 866 } 867 if (phdyn == NULL) { 868 link_elf_error(filename, "Object is not dynamically-linked"); 869 error = ENOEXEC; 870 goto out; 871 } 872 if (nsegs == 0) { 873 link_elf_error(filename, "No sections"); 874 error = ENOEXEC; 875 goto out; 876 } 877 878 /* 879 * Allocate the entire address space of the object, to stake 880 * out our contiguous region, and to establish the base 881 * address for relocation. 882 */ 883 base_offset = trunc_page(segs[0]->p_offset); 884 base_vaddr = trunc_page(segs[0]->p_vaddr); 885 base_vlimit = round_page(segs[nsegs - 1]->p_vaddr + 886 segs[nsegs - 1]->p_memsz); 887 mapsize = base_vlimit - base_vaddr; 888 889 lf = linker_make_file(filename, &link_elf_class); 890 if (lf == NULL) { 891 error = ENOMEM; 892 goto out; 893 } 894 895 ef = (elf_file_t) lf; 896#ifdef SPARSE_MAPPING 897 ef->object = vm_object_allocate(OBJT_DEFAULT, mapsize >> PAGE_SHIFT); 898 if (ef->object == NULL) { 899 error = ENOMEM; 900 goto out; 901 } 902 ef->address = (caddr_t) vm_map_min(kernel_map); 903 error = vm_map_find(kernel_map, ef->object, 0, 904 (vm_offset_t *) &ef->address, mapsize, 1, 905 VM_PROT_ALL, VM_PROT_ALL, 0); 906 if (error != 0) { 907 vm_object_deallocate(ef->object); 908 ef->object = 0; 909 goto out; 910 } 911#else 912 ef->address = malloc(mapsize, M_LINKER, M_WAITOK); 913#endif 914 mapbase = ef->address; 915 916 /* 917 * Read the text and data sections and zero the bss. 918 */ 919 for (i = 0; i < nsegs; i++) { 920 caddr_t segbase = mapbase + segs[i]->p_vaddr - base_vaddr; 921 error = vn_rdwr(UIO_READ, nd.ni_vp, 922 segbase, segs[i]->p_filesz, segs[i]->p_offset, 923 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 924 &resid, td); 925 if (error != 0) 926 goto out; 927 bzero(segbase + segs[i]->p_filesz, 928 segs[i]->p_memsz - segs[i]->p_filesz); 929 930#ifdef SPARSE_MAPPING 931 /* 932 * Wire down the pages 933 */ 934 error = vm_map_wire(kernel_map, 935 (vm_offset_t) segbase, 936 (vm_offset_t) segbase + segs[i]->p_memsz, 937 VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES); 938 if (error != KERN_SUCCESS) { 939 error = ENOMEM; 940 goto out; 941 } 942#endif 943 } 944 945#ifdef GPROF 946 /* Update profiling information with the new text segment. */ 947 mtx_lock(&Giant); 948 kmupetext((uintfptr_t)(mapbase + segs[0]->p_vaddr - base_vaddr + 949 segs[0]->p_memsz)); 950 mtx_unlock(&Giant); 951#endif 952 953 ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr); 954 955 lf->address = ef->address; 956 lf->size = mapsize; 957 958 error = parse_dynamic(ef); 959 if (error != 0) 960 goto out; 961 error = parse_dpcpu(ef); 962 if (error != 0) 963 goto out; 964#ifdef VIMAGE 965 error = parse_vnet(ef); 966 if (error != 0) 967 goto out; 968#endif 969 link_elf_reloc_local(lf); 970 971 VOP_UNLOCK(nd.ni_vp, 0); 972 error = linker_load_dependencies(lf); 973 vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY); 974 if (error != 0) 975 goto out; 976#if 0 /* this will be more trouble than it's worth for now */ 977 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) { 978 if (dp->d_tag != DT_NEEDED) 979 continue; 980 modname = ef->strtab + dp->d_un.d_val; 981 error = linker_load_module(modname, lf); 982 if (error != 0) 983 goto out; 984 } 985#endif 986 error = relocate_file(ef); 987 if (error != 0) 988 goto out; 989 990 /* 991 * Try and load the symbol table if it's present. (you can 992 * strip it!) 993 */ 994 nbytes = hdr->e_shnum * hdr->e_shentsize; 995 if (nbytes == 0 || hdr->e_shoff == 0) 996 goto nosyms; 997 shdr = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO); 998 error = vn_rdwr(UIO_READ, nd.ni_vp, 999 (caddr_t)shdr, nbytes, hdr->e_shoff, 1000 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1001 &resid, td); 1002 if (error != 0) 1003 goto out; 1004 symtabindex = -1; 1005 symstrindex = -1; 1006 for (i = 0; i < hdr->e_shnum; i++) { 1007 if (shdr[i].sh_type == SHT_SYMTAB) { 1008 symtabindex = i; 1009 symstrindex = shdr[i].sh_link; 1010 } 1011 } 1012 if (symtabindex < 0 || symstrindex < 0) 1013 goto nosyms; 1014 1015 symcnt = shdr[symtabindex].sh_size; 1016 ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK); 1017 strcnt = shdr[symstrindex].sh_size; 1018 ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK); 1019 1020 error = vn_rdwr(UIO_READ, nd.ni_vp, 1021 ef->symbase, symcnt, shdr[symtabindex].sh_offset, 1022 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1023 &resid, td); 1024 if (error != 0) 1025 goto out; 1026 error = vn_rdwr(UIO_READ, nd.ni_vp, 1027 ef->strbase, strcnt, shdr[symstrindex].sh_offset, 1028 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1029 &resid, td); 1030 if (error != 0) 1031 goto out; 1032 1033 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym); 1034 ef->ddbsymtab = (const Elf_Sym *)ef->symbase; 1035 ef->ddbstrcnt = strcnt; 1036 ef->ddbstrtab = ef->strbase; 1037 1038nosyms: 1039 error = link_elf_link_common_finish(lf); 1040 if (error != 0) 1041 goto out; 1042 1043 *result = lf; 1044 1045out: 1046 VOP_UNLOCK(nd.ni_vp, 0); 1047 vn_close(nd.ni_vp, FREAD, td->td_ucred, td); 1048 if (error != 0 && lf != NULL) 1049 linker_file_unload(lf, LINKER_UNLOAD_FORCE); 1050 if (shdr != NULL) 1051 free(shdr, M_LINKER); 1052 if (firstpage != NULL) 1053 free(firstpage, M_LINKER); 1054 1055 return (error); 1056} 1057 1058Elf_Addr 1059elf_relocaddr(linker_file_t lf, Elf_Addr x) 1060{ 1061 elf_file_t ef; 1062 1063 ef = (elf_file_t)lf; 1064 if (x >= ef->pcpu_start && x < ef->pcpu_stop) 1065 return ((x - ef->pcpu_start) + ef->pcpu_base); 1066#ifdef VIMAGE 1067 if (x >= ef->vnet_start && x < ef->vnet_stop) 1068 return ((x - ef->vnet_start) + ef->vnet_base); 1069#endif 1070 return (x); 1071} 1072 1073 1074static void 1075link_elf_unload_file(linker_file_t file) 1076{ 1077 elf_file_t ef = (elf_file_t) file; 1078 1079 if (ef->pcpu_base != 0) { 1080 dpcpu_free((void *)ef->pcpu_base, 1081 ef->pcpu_stop - ef->pcpu_start); 1082 elf_set_delete(&set_pcpu_list, ef->pcpu_start); 1083 } 1084#ifdef VIMAGE 1085 if (ef->vnet_base != 0) { 1086 vnet_data_free((void *)ef->vnet_base, 1087 ef->vnet_stop - ef->vnet_start); 1088 elf_set_delete(&set_vnet_list, ef->vnet_start); 1089 } 1090#endif 1091#ifdef GDB 1092 if (ef->gdb.l_ld != NULL) { 1093 GDB_STATE(RT_DELETE); 1094 free((void *)(uintptr_t)ef->gdb.l_name, M_LINKER); 1095 link_elf_delete_gdb(&ef->gdb); 1096 GDB_STATE(RT_CONSISTENT); 1097 } 1098#endif 1099 1100 /* Notify MD code that a module is being unloaded. */ 1101 elf_cpu_unload_file(file); 1102 1103 if (ef->preloaded) { 1104 link_elf_unload_preload(file); 1105 return; 1106 } 1107 1108#ifdef SPARSE_MAPPING 1109 if (ef->object != NULL) { 1110 vm_map_remove(kernel_map, (vm_offset_t) ef->address, 1111 (vm_offset_t) ef->address 1112 + (ef->object->size << PAGE_SHIFT)); 1113 } 1114#else 1115 if (ef->address != NULL) 1116 free(ef->address, M_LINKER); 1117#endif 1118 if (ef->symbase != NULL) 1119 free(ef->symbase, M_LINKER); 1120 if (ef->strbase != NULL) 1121 free(ef->strbase, M_LINKER); 1122 if (ef->ctftab != NULL) 1123 free(ef->ctftab, M_LINKER); 1124 if (ef->ctfoff != NULL) 1125 free(ef->ctfoff, M_LINKER); 1126 if (ef->typoff != NULL) 1127 free(ef->typoff, M_LINKER); 1128} 1129 1130static void 1131link_elf_unload_preload(linker_file_t file) 1132{ 1133 if (file->filename != NULL) 1134 preload_delete_name(file->filename); 1135} 1136 1137static const char * 1138symbol_name(elf_file_t ef, Elf_Size r_info) 1139{ 1140 const Elf_Sym *ref; 1141 1142 if (ELF_R_SYM(r_info)) { 1143 ref = ef->symtab + ELF_R_SYM(r_info); 1144 return (ef->strtab + ref->st_name); 1145 } 1146 return (NULL); 1147} 1148 1149static int 1150relocate_file(elf_file_t ef) 1151{ 1152 const Elf_Rel *rellim; 1153 const Elf_Rel *rel; 1154 const Elf_Rela *relalim; 1155 const Elf_Rela *rela; 1156 const char *symname; 1157 1158 /* Perform relocations without addend if there are any: */ 1159 rel = ef->rel; 1160 if (rel != NULL) { 1161 rellim = (const Elf_Rel *) 1162 ((const char *)ef->rel + ef->relsize); 1163 while (rel < rellim) { 1164 if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rel, 1165 ELF_RELOC_REL, elf_lookup)) { 1166 symname = symbol_name(ef, rel->r_info); 1167 printf("link_elf: symbol %s undefined\n", symname); 1168 return (ENOENT); 1169 } 1170 rel++; 1171 } 1172 } 1173 1174 /* Perform relocations with addend if there are any: */ 1175 rela = ef->rela; 1176 if (rela != NULL) { 1177 relalim = (const Elf_Rela *) 1178 ((const char *)ef->rela + ef->relasize); 1179 while (rela < relalim) { 1180 if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rela, 1181 ELF_RELOC_RELA, elf_lookup)) { 1182 symname = symbol_name(ef, rela->r_info); 1183 printf("link_elf: symbol %s undefined\n", 1184 symname); 1185 return (ENOENT); 1186 } 1187 rela++; 1188 } 1189 } 1190 1191 /* Perform PLT relocations without addend if there are any: */ 1192 rel = ef->pltrel; 1193 if (rel != NULL) { 1194 rellim = (const Elf_Rel *) 1195 ((const char *)ef->pltrel + ef->pltrelsize); 1196 while (rel < rellim) { 1197 if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rel, 1198 ELF_RELOC_REL, elf_lookup)) { 1199 symname = symbol_name(ef, rel->r_info); 1200 printf("link_elf: symbol %s undefined\n", 1201 symname); 1202 return (ENOENT); 1203 } 1204 rel++; 1205 } 1206 } 1207 1208 /* Perform relocations with addend if there are any: */ 1209 rela = ef->pltrela; 1210 if (rela != NULL) { 1211 relalim = (const Elf_Rela *) 1212 ((const char *)ef->pltrela + ef->pltrelasize); 1213 while (rela < relalim) { 1214 if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rela, 1215 ELF_RELOC_RELA, elf_lookup)) { 1216 symname = symbol_name(ef, rela->r_info); 1217 printf("link_elf: symbol %s undefined\n", 1218 symname); 1219 return (ENOENT); 1220 } 1221 rela++; 1222 } 1223 } 1224 1225 return (0); 1226} 1227 1228/* 1229 * Hash function for symbol table lookup. Don't even think about changing 1230 * this. It is specified by the System V ABI. 1231 */ 1232static unsigned long 1233elf_hash(const char *name) 1234{ 1235 const unsigned char *p = (const unsigned char *) name; 1236 unsigned long h = 0; 1237 unsigned long g; 1238 1239 while (*p != '\0') { 1240 h = (h << 4) + *p++; 1241 if ((g = h & 0xf0000000) != 0) 1242 h ^= g >> 24; 1243 h &= ~g; 1244 } 1245 return (h); 1246} 1247 1248static int 1249link_elf_lookup_symbol(linker_file_t lf, const char* name, c_linker_sym_t* sym) 1250{ 1251 elf_file_t ef = (elf_file_t) lf; 1252 unsigned long symnum; 1253 const Elf_Sym* symp; 1254 const char *strp; 1255 unsigned long hash; 1256 int i; 1257 1258 /* If we don't have a hash, bail. */ 1259 if (ef->buckets == NULL || ef->nbuckets == 0) { 1260 printf("link_elf_lookup_symbol: missing symbol hash table\n"); 1261 return (ENOENT); 1262 } 1263 1264 /* First, search hashed global symbols */ 1265 hash = elf_hash(name); 1266 symnum = ef->buckets[hash % ef->nbuckets]; 1267 1268 while (symnum != STN_UNDEF) { 1269 if (symnum >= ef->nchains) { 1270 printf("%s: corrupt symbol table\n", __func__); 1271 return (ENOENT); 1272 } 1273 1274 symp = ef->symtab + symnum; 1275 if (symp->st_name == 0) { 1276 printf("%s: corrupt symbol table\n", __func__); 1277 return (ENOENT); 1278 } 1279 1280 strp = ef->strtab + symp->st_name; 1281 1282 if (strcmp(name, strp) == 0) { 1283 if (symp->st_shndx != SHN_UNDEF || 1284 (symp->st_value != 0 && 1285 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) { 1286 *sym = (c_linker_sym_t) symp; 1287 return (0); 1288 } 1289 return (ENOENT); 1290 } 1291 1292 symnum = ef->chains[symnum]; 1293 } 1294 1295 /* If we have not found it, look at the full table (if loaded) */ 1296 if (ef->symtab == ef->ddbsymtab) 1297 return (ENOENT); 1298 1299 /* Exhaustive search */ 1300 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1301 strp = ef->ddbstrtab + symp->st_name; 1302 if (strcmp(name, strp) == 0) { 1303 if (symp->st_shndx != SHN_UNDEF || 1304 (symp->st_value != 0 && 1305 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) { 1306 *sym = (c_linker_sym_t) symp; 1307 return (0); 1308 } 1309 return (ENOENT); 1310 } 1311 } 1312 1313 return (ENOENT); 1314} 1315 1316static int 1317link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, 1318 linker_symval_t *symval) 1319{ 1320 elf_file_t ef = (elf_file_t) lf; 1321 const Elf_Sym* es = (const Elf_Sym*) sym; 1322 1323 if (es >= ef->symtab && es < (ef->symtab + ef->nchains)) { 1324 symval->name = ef->strtab + es->st_name; 1325 symval->value = (caddr_t) ef->address + es->st_value; 1326 symval->size = es->st_size; 1327 return (0); 1328 } 1329 if (ef->symtab == ef->ddbsymtab) 1330 return (ENOENT); 1331 if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) { 1332 symval->name = ef->ddbstrtab + es->st_name; 1333 symval->value = (caddr_t) ef->address + es->st_value; 1334 symval->size = es->st_size; 1335 return (0); 1336 } 1337 return (ENOENT); 1338} 1339 1340static int 1341link_elf_search_symbol(linker_file_t lf, caddr_t value, 1342 c_linker_sym_t *sym, long *diffp) 1343{ 1344 elf_file_t ef = (elf_file_t) lf; 1345 u_long off = (uintptr_t) (void *) value; 1346 u_long diff = off; 1347 u_long st_value; 1348 const Elf_Sym* es; 1349 const Elf_Sym* best = 0; 1350 int i; 1351 1352 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) { 1353 if (es->st_name == 0) 1354 continue; 1355 st_value = es->st_value + (uintptr_t) (void *) ef->address; 1356 if (off >= st_value) { 1357 if (off - st_value < diff) { 1358 diff = off - st_value; 1359 best = es; 1360 if (diff == 0) 1361 break; 1362 } else if (off - st_value == diff) { 1363 best = es; 1364 } 1365 } 1366 } 1367 if (best == 0) 1368 *diffp = off; 1369 else 1370 *diffp = diff; 1371 *sym = (c_linker_sym_t) best; 1372 1373 return (0); 1374} 1375 1376/* 1377 * Look up a linker set on an ELF system. 1378 */ 1379static int 1380link_elf_lookup_set(linker_file_t lf, const char *name, 1381 void ***startp, void ***stopp, int *countp) 1382{ 1383 c_linker_sym_t sym; 1384 linker_symval_t symval; 1385 char *setsym; 1386 void **start, **stop; 1387 int len, error = 0, count; 1388 1389 len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */ 1390 setsym = malloc(len, M_LINKER, M_WAITOK); 1391 1392 /* get address of first entry */ 1393 snprintf(setsym, len, "%s%s", "__start_set_", name); 1394 error = link_elf_lookup_symbol(lf, setsym, &sym); 1395 if (error != 0) 1396 goto out; 1397 link_elf_symbol_values(lf, sym, &symval); 1398 if (symval.value == 0) { 1399 error = ESRCH; 1400 goto out; 1401 } 1402 start = (void **)symval.value; 1403 1404 /* get address of last entry */ 1405 snprintf(setsym, len, "%s%s", "__stop_set_", name); 1406 error = link_elf_lookup_symbol(lf, setsym, &sym); 1407 if (error != 0) 1408 goto out; 1409 link_elf_symbol_values(lf, sym, &symval); 1410 if (symval.value == 0) { 1411 error = ESRCH; 1412 goto out; 1413 } 1414 stop = (void **)symval.value; 1415 1416 /* and the number of entries */ 1417 count = stop - start; 1418 1419 /* and copy out */ 1420 if (startp != NULL) 1421 *startp = start; 1422 if (stopp != NULL) 1423 *stopp = stop; 1424 if (countp != NULL) 1425 *countp = count; 1426 1427out: 1428 free(setsym, M_LINKER); 1429 return (error); 1430} 1431 1432static int 1433link_elf_each_function_name(linker_file_t file, 1434 int (*callback)(const char *, void *), void *opaque) 1435{ 1436 elf_file_t ef = (elf_file_t)file; 1437 const Elf_Sym *symp; 1438 int i, error; 1439 1440 /* Exhaustive search */ 1441 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1442 if (symp->st_value != 0 && 1443 ELF_ST_TYPE(symp->st_info) == STT_FUNC) { 1444 error = callback(ef->ddbstrtab + symp->st_name, opaque); 1445 if (error != 0) 1446 return (error); 1447 } 1448 } 1449 return (0); 1450} 1451 1452static int 1453link_elf_each_function_nameval(linker_file_t file, 1454 linker_function_nameval_callback_t callback, void *opaque) 1455{ 1456 linker_symval_t symval; 1457 elf_file_t ef = (elf_file_t)file; 1458 const Elf_Sym* symp; 1459 int i, error; 1460 1461 /* Exhaustive search */ 1462 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1463 if (symp->st_value != 0 && 1464 ELF_ST_TYPE(symp->st_info) == STT_FUNC) { 1465 error = link_elf_symbol_values(file, 1466 (c_linker_sym_t) symp, &symval); 1467 if (error != 0) 1468 return (error); 1469 error = callback(file, i, &symval, opaque); 1470 if (error != 0) 1471 return (error); 1472 } 1473 } 1474 return (0); 1475} 1476 1477#ifdef __ia64__ 1478/* 1479 * Each KLD has its own GP. The GP value for each load module is given by 1480 * DT_PLTGOT on ia64. We need GP to construct function descriptors, but 1481 * don't have direct access to the ELF file structure. The link_elf_get_gp() 1482 * function returns the GP given a pointer to a generic linker file struct. 1483 */ 1484Elf_Addr 1485link_elf_get_gp(linker_file_t lf) 1486{ 1487 elf_file_t ef = (elf_file_t)lf; 1488 return ((Elf_Addr)ef->got); 1489} 1490#endif 1491 1492const Elf_Sym * 1493elf_get_sym(linker_file_t lf, Elf_Size symidx) 1494{ 1495 elf_file_t ef = (elf_file_t)lf; 1496 1497 if (symidx >= ef->nchains) 1498 return (NULL); 1499 return (ef->symtab + symidx); 1500} 1501 1502const char * 1503elf_get_symname(linker_file_t lf, Elf_Size symidx) 1504{ 1505 elf_file_t ef = (elf_file_t)lf; 1506 const Elf_Sym *sym; 1507 1508 if (symidx >= ef->nchains) 1509 return (NULL); 1510 sym = ef->symtab + symidx; 1511 return (ef->strtab + sym->st_name); 1512} 1513 1514/* 1515 * Symbol lookup function that can be used when the symbol index is known (ie 1516 * in relocations). It uses the symbol index instead of doing a fully fledged 1517 * hash table based lookup when such is valid. For example for local symbols. 1518 * This is not only more efficient, it's also more correct. It's not always 1519 * the case that the symbol can be found through the hash table. 1520 */ 1521static Elf_Addr 1522elf_lookup(linker_file_t lf, Elf_Size symidx, int deps) 1523{ 1524 elf_file_t ef = (elf_file_t)lf; 1525 const Elf_Sym *sym; 1526 const char *symbol; 1527 Elf_Addr addr, start, base; 1528 1529 /* Don't even try to lookup the symbol if the index is bogus. */ 1530 if (symidx >= ef->nchains) 1531 return (0); 1532 1533 sym = ef->symtab + symidx; 1534 1535 /* 1536 * Don't do a full lookup when the symbol is local. It may even 1537 * fail because it may not be found through the hash table. 1538 */ 1539 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) { 1540 /* Force lookup failure when we have an insanity. */ 1541 if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0) 1542 return (0); 1543 return ((Elf_Addr)ef->address + sym->st_value); 1544 } 1545 1546 /* 1547 * XXX we can avoid doing a hash table based lookup for global 1548 * symbols as well. This however is not always valid, so we'll 1549 * just do it the hard way for now. Performance tweaks can 1550 * always be added. 1551 */ 1552 1553 symbol = ef->strtab + sym->st_name; 1554 1555 /* Force a lookup failure if the symbol name is bogus. */ 1556 if (*symbol == 0) 1557 return (0); 1558 1559 addr = ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps)); 1560 1561 if (elf_set_find(&set_pcpu_list, addr, &start, &base)) 1562 addr = addr - start + base; 1563#ifdef VIMAGE 1564 else if (elf_set_find(&set_vnet_list, addr, &start, &base)) 1565 addr = addr - start + base; 1566#endif 1567 return addr; 1568} 1569 1570static void 1571link_elf_reloc_local(linker_file_t lf) 1572{ 1573 const Elf_Rel *rellim; 1574 const Elf_Rel *rel; 1575 const Elf_Rela *relalim; 1576 const Elf_Rela *rela; 1577 elf_file_t ef = (elf_file_t)lf; 1578 1579 /* Perform relocations without addend if there are any: */ 1580 if ((rel = ef->rel) != NULL) { 1581 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize); 1582 while (rel < rellim) { 1583 elf_reloc_local(lf, (Elf_Addr)ef->address, rel, 1584 ELF_RELOC_REL, elf_lookup); 1585 rel++; 1586 } 1587 } 1588 1589 /* Perform relocations with addend if there are any: */ 1590 if ((rela = ef->rela) != NULL) { 1591 relalim = (const Elf_Rela *) 1592 ((const char *)ef->rela + ef->relasize); 1593 while (rela < relalim) { 1594 elf_reloc_local(lf, (Elf_Addr)ef->address, rela, 1595 ELF_RELOC_RELA, elf_lookup); 1596 rela++; 1597 } 1598 } 1599} 1600 1601static long 1602link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab) 1603{ 1604 elf_file_t ef = (elf_file_t)lf; 1605 1606 *symtab = ef->ddbsymtab; 1607 1608 if (*symtab == NULL) 1609 return (0); 1610 1611 return (ef->ddbsymcnt); 1612} 1613 1614static long 1615link_elf_strtab_get(linker_file_t lf, caddr_t *strtab) 1616{ 1617 elf_file_t ef = (elf_file_t)lf; 1618 1619 *strtab = ef->ddbstrtab; 1620 1621 if (*strtab == NULL) 1622 return (0); 1623 1624 return (ef->ddbstrcnt); 1625} 1626