Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/kern/link_elf.c
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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: releng/10.0/sys/kern/link_elf.c 255426 2013-09-09 18:11:59Z jhb $"); 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 76 typedef 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; 125 126 struct 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 }; 132 133 TAILQ_HEAD(elf_set_head, elf_set); 134 135 #include <kern/kern_ctf.c> 136 137 static int link_elf_link_common_finish(linker_file_t); 138 static int link_elf_link_preload(linker_class_t cls, 139 const char *, linker_file_t *); 140 static int link_elf_link_preload_finish(linker_file_t); 141 static int link_elf_load_file(linker_class_t, const char *, 142 linker_file_t *); 143 static int link_elf_lookup_symbol(linker_file_t, const char *, 144 c_linker_sym_t *); 145 static int link_elf_symbol_values(linker_file_t, c_linker_sym_t, 146 linker_symval_t *); 147 static int link_elf_search_symbol(linker_file_t, caddr_t, 148 c_linker_sym_t *, long *); 149 150 static void link_elf_unload_file(linker_file_t); 151 static void link_elf_unload_preload(linker_file_t); 152 static int link_elf_lookup_set(linker_file_t, const char *, 153 void ***, void ***, int *); 154 static int link_elf_each_function_name(linker_file_t, 155 int (*)(const char *, void *), void *); 156 static int link_elf_each_function_nameval(linker_file_t, 157 linker_function_nameval_callback_t, void *); 158 static void link_elf_reloc_local(linker_file_t); 159 static long link_elf_symtab_get(linker_file_t, const Elf_Sym **); 160 static long link_elf_strtab_get(linker_file_t, caddr_t *); 161 static Elf_Addr elf_lookup(linker_file_t, Elf_Size, int); 162 163 static 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 }; 179 180 static 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 }; 188 189 static int parse_dynamic(elf_file_t); 190 static int relocate_file(elf_file_t); 191 static int link_elf_preload_parse_symbols(elf_file_t); 192 193 static struct elf_set_head set_pcpu_list; 194 #ifdef VIMAGE 195 static struct elf_set_head set_vnet_list; 196 #endif 197 198 static void 199 elf_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 } 225 226 static int 227 elf_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 } 243 244 static void 245 elf_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 263 static 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 */ 268 struct 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 */ 277 static void 278 r_debug_state(struct r_debug *dummy_one __unused, 279 struct link_map *dummy_two __unused) 280 { 281 } 282 283 static void 284 link_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 } 304 305 static void 306 link_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__ 321 Elf_Addr link_elf_get_gp(linker_file_t); 322 #endif 323 324 /* 325 * The kernel symbol table starts here. 326 */ 327 extern struct _dynamic _DYNAMIC; 328 329 static void 330 link_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 */ 342 static int 343 link_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 } 369 370 static void 371 link_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 } 431 432 SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_THIRD, link_elf_init, 0); 433 434 static int 435 link_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 } 486 487 static int 488 parse_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 } 575 576 static int 577 parse_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 607 static int 608 parse_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 637 638 static int 639 link_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 } 697 698 static int 699 link_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 error = relocate_file(ef); 706 if (error != 0) 707 return (error); 708 (void)link_elf_preload_parse_symbols(ef); 709 710 return (link_elf_link_common_finish(lf)); 711 } 712 713 static int 714 link_elf_load_file(linker_class_t cls, const char* filename, 715 linker_file_t* result) 716 { 717 struct nameidata nd; 718 struct thread* td = curthread; /* XXX */ 719 Elf_Ehdr *hdr; 720 caddr_t firstpage; 721 int nbytes, i; 722 Elf_Phdr *phdr; 723 Elf_Phdr *phlimit; 724 Elf_Phdr *segs[MAXSEGS]; 725 int nsegs; 726 Elf_Phdr *phdyn; 727 Elf_Phdr *phphdr; 728 caddr_t mapbase; 729 size_t mapsize; 730 Elf_Off base_offset; 731 Elf_Addr base_vaddr; 732 Elf_Addr base_vlimit; 733 int error = 0; 734 ssize_t resid; 735 int flags; 736 elf_file_t ef; 737 linker_file_t lf; 738 Elf_Shdr *shdr; 739 int symtabindex; 740 int symstrindex; 741 int symcnt; 742 int strcnt; 743 744 shdr = NULL; 745 lf = NULL; 746 747 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td); 748 flags = FREAD; 749 error = vn_open(&nd, &flags, 0, NULL); 750 if (error != 0) 751 return (error); 752 NDFREE(&nd, NDF_ONLY_PNBUF); 753 if (nd.ni_vp->v_type != VREG) { 754 error = ENOEXEC; 755 firstpage = NULL; 756 goto out; 757 } 758 #ifdef MAC 759 error = mac_kld_check_load(curthread->td_ucred, nd.ni_vp); 760 if (error != 0) { 761 firstpage = NULL; 762 goto out; 763 } 764 #endif 765 766 /* 767 * Read the elf header from the file. 768 */ 769 firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK); 770 hdr = (Elf_Ehdr *)firstpage; 771 error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0, 772 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 773 &resid, td); 774 nbytes = PAGE_SIZE - resid; 775 if (error != 0) 776 goto out; 777 778 if (!IS_ELF(*hdr)) { 779 error = ENOEXEC; 780 goto out; 781 } 782 783 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS || 784 hdr->e_ident[EI_DATA] != ELF_TARG_DATA) { 785 link_elf_error(filename, "Unsupported file layout"); 786 error = ENOEXEC; 787 goto out; 788 } 789 if (hdr->e_ident[EI_VERSION] != EV_CURRENT || 790 hdr->e_version != EV_CURRENT) { 791 link_elf_error(filename, "Unsupported file version"); 792 error = ENOEXEC; 793 goto out; 794 } 795 if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) { 796 error = ENOSYS; 797 goto out; 798 } 799 if (hdr->e_machine != ELF_TARG_MACH) { 800 link_elf_error(filename, "Unsupported machine"); 801 error = ENOEXEC; 802 goto out; 803 } 804 805 /* 806 * We rely on the program header being in the first page. 807 * This is not strictly required by the ABI specification, but 808 * it seems to always true in practice. And, it simplifies 809 * things considerably. 810 */ 811 if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) && 812 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) && 813 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes))) 814 link_elf_error(filename, "Unreadable program headers"); 815 816 /* 817 * Scan the program header entries, and save key information. 818 * 819 * We rely on there being exactly two load segments, text and data, 820 * in that order. 821 */ 822 phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff); 823 phlimit = phdr + hdr->e_phnum; 824 nsegs = 0; 825 phdyn = NULL; 826 phphdr = NULL; 827 while (phdr < phlimit) { 828 switch (phdr->p_type) { 829 case PT_LOAD: 830 if (nsegs == MAXSEGS) { 831 link_elf_error(filename, "Too many sections"); 832 error = ENOEXEC; 833 goto out; 834 } 835 /* 836 * XXX: We just trust they come in right order ?? 837 */ 838 segs[nsegs] = phdr; 839 ++nsegs; 840 break; 841 842 case PT_PHDR: 843 phphdr = phdr; 844 break; 845 846 case PT_DYNAMIC: 847 phdyn = phdr; 848 break; 849 850 case PT_INTERP: 851 error = ENOSYS; 852 goto out; 853 } 854 855 ++phdr; 856 } 857 if (phdyn == NULL) { 858 link_elf_error(filename, "Object is not dynamically-linked"); 859 error = ENOEXEC; 860 goto out; 861 } 862 if (nsegs == 0) { 863 link_elf_error(filename, "No sections"); 864 error = ENOEXEC; 865 goto out; 866 } 867 868 /* 869 * Allocate the entire address space of the object, to stake 870 * out our contiguous region, and to establish the base 871 * address for relocation. 872 */ 873 base_offset = trunc_page(segs[0]->p_offset); 874 base_vaddr = trunc_page(segs[0]->p_vaddr); 875 base_vlimit = round_page(segs[nsegs - 1]->p_vaddr + 876 segs[nsegs - 1]->p_memsz); 877 mapsize = base_vlimit - base_vaddr; 878 879 lf = linker_make_file(filename, &link_elf_class); 880 if (lf == NULL) { 881 error = ENOMEM; 882 goto out; 883 } 884 885 ef = (elf_file_t) lf; 886 #ifdef SPARSE_MAPPING 887 ef->object = vm_object_allocate(OBJT_DEFAULT, mapsize >> PAGE_SHIFT); 888 if (ef->object == NULL) { 889 error = ENOMEM; 890 goto out; 891 } 892 ef->address = (caddr_t) vm_map_min(kernel_map); 893 error = vm_map_find(kernel_map, ef->object, 0, 894 (vm_offset_t *) &ef->address, mapsize, 0, VMFS_OPTIMAL_SPACE, 895 VM_PROT_ALL, VM_PROT_ALL, 0); 896 if (error != 0) { 897 vm_object_deallocate(ef->object); 898 ef->object = 0; 899 goto out; 900 } 901 #else 902 ef->address = malloc(mapsize, M_LINKER, M_WAITOK); 903 #endif 904 mapbase = ef->address; 905 906 /* 907 * Read the text and data sections and zero the bss. 908 */ 909 for (i = 0; i < nsegs; i++) { 910 caddr_t segbase = mapbase + segs[i]->p_vaddr - base_vaddr; 911 error = vn_rdwr(UIO_READ, nd.ni_vp, 912 segbase, segs[i]->p_filesz, segs[i]->p_offset, 913 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 914 &resid, td); 915 if (error != 0) 916 goto out; 917 bzero(segbase + segs[i]->p_filesz, 918 segs[i]->p_memsz - segs[i]->p_filesz); 919 920 #ifdef SPARSE_MAPPING 921 /* 922 * Wire down the pages 923 */ 924 error = vm_map_wire(kernel_map, 925 (vm_offset_t) segbase, 926 (vm_offset_t) segbase + segs[i]->p_memsz, 927 VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES); 928 if (error != KERN_SUCCESS) { 929 error = ENOMEM; 930 goto out; 931 } 932 #endif 933 } 934 935 #ifdef GPROF 936 /* Update profiling information with the new text segment. */ 937 mtx_lock(&Giant); 938 kmupetext((uintfptr_t)(mapbase + segs[0]->p_vaddr - base_vaddr + 939 segs[0]->p_memsz)); 940 mtx_unlock(&Giant); 941 #endif 942 943 ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr); 944 945 lf->address = ef->address; 946 lf->size = mapsize; 947 948 error = parse_dynamic(ef); 949 if (error != 0) 950 goto out; 951 error = parse_dpcpu(ef); 952 if (error != 0) 953 goto out; 954 #ifdef VIMAGE 955 error = parse_vnet(ef); 956 if (error != 0) 957 goto out; 958 #endif 959 link_elf_reloc_local(lf); 960 961 VOP_UNLOCK(nd.ni_vp, 0); 962 error = linker_load_dependencies(lf); 963 vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY); 964 if (error != 0) 965 goto out; 966 error = relocate_file(ef); 967 if (error != 0) 968 goto out; 969 970 /* 971 * Try and load the symbol table if it's present. (you can 972 * strip it!) 973 */ 974 nbytes = hdr->e_shnum * hdr->e_shentsize; 975 if (nbytes == 0 || hdr->e_shoff == 0) 976 goto nosyms; 977 shdr = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO); 978 error = vn_rdwr(UIO_READ, nd.ni_vp, 979 (caddr_t)shdr, nbytes, hdr->e_shoff, 980 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 981 &resid, td); 982 if (error != 0) 983 goto out; 984 symtabindex = -1; 985 symstrindex = -1; 986 for (i = 0; i < hdr->e_shnum; i++) { 987 if (shdr[i].sh_type == SHT_SYMTAB) { 988 symtabindex = i; 989 symstrindex = shdr[i].sh_link; 990 } 991 } 992 if (symtabindex < 0 || symstrindex < 0) 993 goto nosyms; 994 995 symcnt = shdr[symtabindex].sh_size; 996 ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK); 997 strcnt = shdr[symstrindex].sh_size; 998 ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK); 999 1000 error = vn_rdwr(UIO_READ, nd.ni_vp, 1001 ef->symbase, symcnt, shdr[symtabindex].sh_offset, 1002 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1003 &resid, td); 1004 if (error != 0) 1005 goto out; 1006 error = vn_rdwr(UIO_READ, nd.ni_vp, 1007 ef->strbase, strcnt, shdr[symstrindex].sh_offset, 1008 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1009 &resid, td); 1010 if (error != 0) 1011 goto out; 1012 1013 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym); 1014 ef->ddbsymtab = (const Elf_Sym *)ef->symbase; 1015 ef->ddbstrcnt = strcnt; 1016 ef->ddbstrtab = ef->strbase; 1017 1018 nosyms: 1019 error = link_elf_link_common_finish(lf); 1020 if (error != 0) 1021 goto out; 1022 1023 *result = lf; 1024 1025 out: 1026 VOP_UNLOCK(nd.ni_vp, 0); 1027 vn_close(nd.ni_vp, FREAD, td->td_ucred, td); 1028 if (error != 0 && lf != NULL) 1029 linker_file_unload(lf, LINKER_UNLOAD_FORCE); 1030 if (shdr != NULL) 1031 free(shdr, M_LINKER); 1032 if (firstpage != NULL) 1033 free(firstpage, M_LINKER); 1034 1035 return (error); 1036 } 1037 1038 Elf_Addr 1039 elf_relocaddr(linker_file_t lf, Elf_Addr x) 1040 { 1041 elf_file_t ef; 1042 1043 ef = (elf_file_t)lf; 1044 if (x >= ef->pcpu_start && x < ef->pcpu_stop) 1045 return ((x - ef->pcpu_start) + ef->pcpu_base); 1046 #ifdef VIMAGE 1047 if (x >= ef->vnet_start && x < ef->vnet_stop) 1048 return ((x - ef->vnet_start) + ef->vnet_base); 1049 #endif 1050 return (x); 1051 } 1052 1053 1054 static void 1055 link_elf_unload_file(linker_file_t file) 1056 { 1057 elf_file_t ef = (elf_file_t) file; 1058 1059 if (ef->pcpu_base != 0) { 1060 dpcpu_free((void *)ef->pcpu_base, 1061 ef->pcpu_stop - ef->pcpu_start); 1062 elf_set_delete(&set_pcpu_list, ef->pcpu_start); 1063 } 1064 #ifdef VIMAGE 1065 if (ef->vnet_base != 0) { 1066 vnet_data_free((void *)ef->vnet_base, 1067 ef->vnet_stop - ef->vnet_start); 1068 elf_set_delete(&set_vnet_list, ef->vnet_start); 1069 } 1070 #endif 1071 #ifdef GDB 1072 if (ef->gdb.l_ld != NULL) { 1073 GDB_STATE(RT_DELETE); 1074 free((void *)(uintptr_t)ef->gdb.l_name, M_LINKER); 1075 link_elf_delete_gdb(&ef->gdb); 1076 GDB_STATE(RT_CONSISTENT); 1077 } 1078 #endif 1079 1080 /* Notify MD code that a module is being unloaded. */ 1081 elf_cpu_unload_file(file); 1082 1083 if (ef->preloaded) { 1084 link_elf_unload_preload(file); 1085 return; 1086 } 1087 1088 #ifdef SPARSE_MAPPING 1089 if (ef->object != NULL) { 1090 vm_map_remove(kernel_map, (vm_offset_t) ef->address, 1091 (vm_offset_t) ef->address 1092 + (ef->object->size << PAGE_SHIFT)); 1093 } 1094 #else 1095 if (ef->address != NULL) 1096 free(ef->address, M_LINKER); 1097 #endif 1098 if (ef->symbase != NULL) 1099 free(ef->symbase, M_LINKER); 1100 if (ef->strbase != NULL) 1101 free(ef->strbase, M_LINKER); 1102 if (ef->ctftab != NULL) 1103 free(ef->ctftab, M_LINKER); 1104 if (ef->ctfoff != NULL) 1105 free(ef->ctfoff, M_LINKER); 1106 if (ef->typoff != NULL) 1107 free(ef->typoff, M_LINKER); 1108 } 1109 1110 static void 1111 link_elf_unload_preload(linker_file_t file) 1112 { 1113 if (file->filename != NULL) 1114 preload_delete_name(file->filename); 1115 } 1116 1117 static const char * 1118 symbol_name(elf_file_t ef, Elf_Size r_info) 1119 { 1120 const Elf_Sym *ref; 1121 1122 if (ELF_R_SYM(r_info)) { 1123 ref = ef->symtab + ELF_R_SYM(r_info); 1124 return (ef->strtab + ref->st_name); 1125 } 1126 return (NULL); 1127 } 1128 1129 static int 1130 relocate_file(elf_file_t ef) 1131 { 1132 const Elf_Rel *rellim; 1133 const Elf_Rel *rel; 1134 const Elf_Rela *relalim; 1135 const Elf_Rela *rela; 1136 const char *symname; 1137 1138 /* Perform relocations without addend if there are any: */ 1139 rel = ef->rel; 1140 if (rel != NULL) { 1141 rellim = (const Elf_Rel *) 1142 ((const char *)ef->rel + ef->relsize); 1143 while (rel < rellim) { 1144 if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rel, 1145 ELF_RELOC_REL, elf_lookup)) { 1146 symname = symbol_name(ef, rel->r_info); 1147 printf("link_elf: symbol %s undefined\n", symname); 1148 return (ENOENT); 1149 } 1150 rel++; 1151 } 1152 } 1153 1154 /* Perform relocations with addend if there are any: */ 1155 rela = ef->rela; 1156 if (rela != NULL) { 1157 relalim = (const Elf_Rela *) 1158 ((const char *)ef->rela + ef->relasize); 1159 while (rela < relalim) { 1160 if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rela, 1161 ELF_RELOC_RELA, elf_lookup)) { 1162 symname = symbol_name(ef, rela->r_info); 1163 printf("link_elf: symbol %s undefined\n", 1164 symname); 1165 return (ENOENT); 1166 } 1167 rela++; 1168 } 1169 } 1170 1171 /* Perform PLT relocations without addend if there are any: */ 1172 rel = ef->pltrel; 1173 if (rel != NULL) { 1174 rellim = (const Elf_Rel *) 1175 ((const char *)ef->pltrel + ef->pltrelsize); 1176 while (rel < rellim) { 1177 if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rel, 1178 ELF_RELOC_REL, elf_lookup)) { 1179 symname = symbol_name(ef, rel->r_info); 1180 printf("link_elf: symbol %s undefined\n", 1181 symname); 1182 return (ENOENT); 1183 } 1184 rel++; 1185 } 1186 } 1187 1188 /* Perform relocations with addend if there are any: */ 1189 rela = ef->pltrela; 1190 if (rela != NULL) { 1191 relalim = (const Elf_Rela *) 1192 ((const char *)ef->pltrela + ef->pltrelasize); 1193 while (rela < relalim) { 1194 if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rela, 1195 ELF_RELOC_RELA, elf_lookup)) { 1196 symname = symbol_name(ef, rela->r_info); 1197 printf("link_elf: symbol %s undefined\n", 1198 symname); 1199 return (ENOENT); 1200 } 1201 rela++; 1202 } 1203 } 1204 1205 return (0); 1206 } 1207 1208 /* 1209 * Hash function for symbol table lookup. Don't even think about changing 1210 * this. It is specified by the System V ABI. 1211 */ 1212 static unsigned long 1213 elf_hash(const char *name) 1214 { 1215 const unsigned char *p = (const unsigned char *) name; 1216 unsigned long h = 0; 1217 unsigned long g; 1218 1219 while (*p != '\0') { 1220 h = (h << 4) + *p++; 1221 if ((g = h & 0xf0000000) != 0) 1222 h ^= g >> 24; 1223 h &= ~g; 1224 } 1225 return (h); 1226 } 1227 1228 static int 1229 link_elf_lookup_symbol(linker_file_t lf, const char* name, c_linker_sym_t* sym) 1230 { 1231 elf_file_t ef = (elf_file_t) lf; 1232 unsigned long symnum; 1233 const Elf_Sym* symp; 1234 const char *strp; 1235 unsigned long hash; 1236 int i; 1237 1238 /* If we don't have a hash, bail. */ 1239 if (ef->buckets == NULL || ef->nbuckets == 0) { 1240 printf("link_elf_lookup_symbol: missing symbol hash table\n"); 1241 return (ENOENT); 1242 } 1243 1244 /* First, search hashed global symbols */ 1245 hash = elf_hash(name); 1246 symnum = ef->buckets[hash % ef->nbuckets]; 1247 1248 while (symnum != STN_UNDEF) { 1249 if (symnum >= ef->nchains) { 1250 printf("%s: corrupt symbol table\n", __func__); 1251 return (ENOENT); 1252 } 1253 1254 symp = ef->symtab + symnum; 1255 if (symp->st_name == 0) { 1256 printf("%s: corrupt symbol table\n", __func__); 1257 return (ENOENT); 1258 } 1259 1260 strp = ef->strtab + symp->st_name; 1261 1262 if (strcmp(name, strp) == 0) { 1263 if (symp->st_shndx != SHN_UNDEF || 1264 (symp->st_value != 0 && 1265 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) { 1266 *sym = (c_linker_sym_t) symp; 1267 return (0); 1268 } 1269 return (ENOENT); 1270 } 1271 1272 symnum = ef->chains[symnum]; 1273 } 1274 1275 /* If we have not found it, look at the full table (if loaded) */ 1276 if (ef->symtab == ef->ddbsymtab) 1277 return (ENOENT); 1278 1279 /* Exhaustive search */ 1280 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1281 strp = ef->ddbstrtab + symp->st_name; 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 1293 return (ENOENT); 1294 } 1295 1296 static int 1297 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, 1298 linker_symval_t *symval) 1299 { 1300 elf_file_t ef = (elf_file_t) lf; 1301 const Elf_Sym* es = (const Elf_Sym*) sym; 1302 1303 if (es >= ef->symtab && es < (ef->symtab + ef->nchains)) { 1304 symval->name = ef->strtab + es->st_name; 1305 symval->value = (caddr_t) ef->address + es->st_value; 1306 symval->size = es->st_size; 1307 return (0); 1308 } 1309 if (ef->symtab == ef->ddbsymtab) 1310 return (ENOENT); 1311 if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) { 1312 symval->name = ef->ddbstrtab + es->st_name; 1313 symval->value = (caddr_t) ef->address + es->st_value; 1314 symval->size = es->st_size; 1315 return (0); 1316 } 1317 return (ENOENT); 1318 } 1319 1320 static int 1321 link_elf_search_symbol(linker_file_t lf, caddr_t value, 1322 c_linker_sym_t *sym, long *diffp) 1323 { 1324 elf_file_t ef = (elf_file_t) lf; 1325 u_long off = (uintptr_t) (void *) value; 1326 u_long diff = off; 1327 u_long st_value; 1328 const Elf_Sym* es; 1329 const Elf_Sym* best = 0; 1330 int i; 1331 1332 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) { 1333 if (es->st_name == 0) 1334 continue; 1335 st_value = es->st_value + (uintptr_t) (void *) ef->address; 1336 if (off >= st_value) { 1337 if (off - st_value < diff) { 1338 diff = off - st_value; 1339 best = es; 1340 if (diff == 0) 1341 break; 1342 } else if (off - st_value == diff) { 1343 best = es; 1344 } 1345 } 1346 } 1347 if (best == 0) 1348 *diffp = off; 1349 else 1350 *diffp = diff; 1351 *sym = (c_linker_sym_t) best; 1352 1353 return (0); 1354 } 1355 1356 /* 1357 * Look up a linker set on an ELF system. 1358 */ 1359 static int 1360 link_elf_lookup_set(linker_file_t lf, const char *name, 1361 void ***startp, void ***stopp, int *countp) 1362 { 1363 c_linker_sym_t sym; 1364 linker_symval_t symval; 1365 char *setsym; 1366 void **start, **stop; 1367 int len, error = 0, count; 1368 1369 len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */ 1370 setsym = malloc(len, M_LINKER, M_WAITOK); 1371 1372 /* get address of first entry */ 1373 snprintf(setsym, len, "%s%s", "__start_set_", name); 1374 error = link_elf_lookup_symbol(lf, setsym, &sym); 1375 if (error != 0) 1376 goto out; 1377 link_elf_symbol_values(lf, sym, &symval); 1378 if (symval.value == 0) { 1379 error = ESRCH; 1380 goto out; 1381 } 1382 start = (void **)symval.value; 1383 1384 /* get address of last entry */ 1385 snprintf(setsym, len, "%s%s", "__stop_set_", name); 1386 error = link_elf_lookup_symbol(lf, setsym, &sym); 1387 if (error != 0) 1388 goto out; 1389 link_elf_symbol_values(lf, sym, &symval); 1390 if (symval.value == 0) { 1391 error = ESRCH; 1392 goto out; 1393 } 1394 stop = (void **)symval.value; 1395 1396 /* and the number of entries */ 1397 count = stop - start; 1398 1399 /* and copy out */ 1400 if (startp != NULL) 1401 *startp = start; 1402 if (stopp != NULL) 1403 *stopp = stop; 1404 if (countp != NULL) 1405 *countp = count; 1406 1407 out: 1408 free(setsym, M_LINKER); 1409 return (error); 1410 } 1411 1412 static int 1413 link_elf_each_function_name(linker_file_t file, 1414 int (*callback)(const char *, void *), void *opaque) 1415 { 1416 elf_file_t ef = (elf_file_t)file; 1417 const Elf_Sym *symp; 1418 int i, error; 1419 1420 /* Exhaustive search */ 1421 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1422 if (symp->st_value != 0 && 1423 ELF_ST_TYPE(symp->st_info) == STT_FUNC) { 1424 error = callback(ef->ddbstrtab + symp->st_name, opaque); 1425 if (error != 0) 1426 return (error); 1427 } 1428 } 1429 return (0); 1430 } 1431 1432 static int 1433 link_elf_each_function_nameval(linker_file_t file, 1434 linker_function_nameval_callback_t callback, void *opaque) 1435 { 1436 linker_symval_t symval; 1437 elf_file_t ef = (elf_file_t)file; 1438 const Elf_Sym* symp; 1439 int i, error; 1440 1441 /* Exhaustive search */ 1442 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1443 if (symp->st_value != 0 && 1444 ELF_ST_TYPE(symp->st_info) == STT_FUNC) { 1445 error = link_elf_symbol_values(file, 1446 (c_linker_sym_t) symp, &symval); 1447 if (error != 0) 1448 return (error); 1449 error = callback(file, i, &symval, opaque); 1450 if (error != 0) 1451 return (error); 1452 } 1453 } 1454 return (0); 1455 } 1456 1457 #ifdef __ia64__ 1458 /* 1459 * Each KLD has its own GP. The GP value for each load module is given by 1460 * DT_PLTGOT on ia64. We need GP to construct function descriptors, but 1461 * don't have direct access to the ELF file structure. The link_elf_get_gp() 1462 * function returns the GP given a pointer to a generic linker file struct. 1463 */ 1464 Elf_Addr 1465 link_elf_get_gp(linker_file_t lf) 1466 { 1467 elf_file_t ef = (elf_file_t)lf; 1468 return ((Elf_Addr)ef->got); 1469 } 1470 #endif 1471 1472 const Elf_Sym * 1473 elf_get_sym(linker_file_t lf, Elf_Size symidx) 1474 { 1475 elf_file_t ef = (elf_file_t)lf; 1476 1477 if (symidx >= ef->nchains) 1478 return (NULL); 1479 return (ef->symtab + symidx); 1480 } 1481 1482 const char * 1483 elf_get_symname(linker_file_t lf, Elf_Size symidx) 1484 { 1485 elf_file_t ef = (elf_file_t)lf; 1486 const Elf_Sym *sym; 1487 1488 if (symidx >= ef->nchains) 1489 return (NULL); 1490 sym = ef->symtab + symidx; 1491 return (ef->strtab + sym->st_name); 1492 } 1493 1494 /* 1495 * Symbol lookup function that can be used when the symbol index is known (ie 1496 * in relocations). It uses the symbol index instead of doing a fully fledged 1497 * hash table based lookup when such is valid. For example for local symbols. 1498 * This is not only more efficient, it's also more correct. It's not always 1499 * the case that the symbol can be found through the hash table. 1500 */ 1501 static Elf_Addr 1502 elf_lookup(linker_file_t lf, Elf_Size symidx, int deps) 1503 { 1504 elf_file_t ef = (elf_file_t)lf; 1505 const Elf_Sym *sym; 1506 const char *symbol; 1507 Elf_Addr addr, start, base; 1508 1509 /* Don't even try to lookup the symbol if the index is bogus. */ 1510 if (symidx >= ef->nchains) 1511 return (0); 1512 1513 sym = ef->symtab + symidx; 1514 1515 /* 1516 * Don't do a full lookup when the symbol is local. It may even 1517 * fail because it may not be found through the hash table. 1518 */ 1519 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) { 1520 /* Force lookup failure when we have an insanity. */ 1521 if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0) 1522 return (0); 1523 return ((Elf_Addr)ef->address + sym->st_value); 1524 } 1525 1526 /* 1527 * XXX we can avoid doing a hash table based lookup for global 1528 * symbols as well. This however is not always valid, so we'll 1529 * just do it the hard way for now. Performance tweaks can 1530 * always be added. 1531 */ 1532 1533 symbol = ef->strtab + sym->st_name; 1534 1535 /* Force a lookup failure if the symbol name is bogus. */ 1536 if (*symbol == 0) 1537 return (0); 1538 1539 addr = ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps)); 1540 1541 if (elf_set_find(&set_pcpu_list, addr, &start, &base)) 1542 addr = addr - start + base; 1543 #ifdef VIMAGE 1544 else if (elf_set_find(&set_vnet_list, addr, &start, &base)) 1545 addr = addr - start + base; 1546 #endif 1547 return addr; 1548 } 1549 1550 static void 1551 link_elf_reloc_local(linker_file_t lf) 1552 { 1553 const Elf_Rel *rellim; 1554 const Elf_Rel *rel; 1555 const Elf_Rela *relalim; 1556 const Elf_Rela *rela; 1557 elf_file_t ef = (elf_file_t)lf; 1558 1559 /* Perform relocations without addend if there are any: */ 1560 if ((rel = ef->rel) != NULL) { 1561 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize); 1562 while (rel < rellim) { 1563 elf_reloc_local(lf, (Elf_Addr)ef->address, rel, 1564 ELF_RELOC_REL, elf_lookup); 1565 rel++; 1566 } 1567 } 1568 1569 /* Perform relocations with addend if there are any: */ 1570 if ((rela = ef->rela) != NULL) { 1571 relalim = (const Elf_Rela *) 1572 ((const char *)ef->rela + ef->relasize); 1573 while (rela < relalim) { 1574 elf_reloc_local(lf, (Elf_Addr)ef->address, rela, 1575 ELF_RELOC_RELA, elf_lookup); 1576 rela++; 1577 } 1578 } 1579 } 1580 1581 static long 1582 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab) 1583 { 1584 elf_file_t ef = (elf_file_t)lf; 1585 1586 *symtab = ef->ddbsymtab; 1587 1588 if (*symtab == NULL) 1589 return (0); 1590 1591 return (ef->ddbsymcnt); 1592 } 1593 1594 static long 1595 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab) 1596 { 1597 elf_file_t ef = (elf_file_t)lf; 1598 1599 *strtab = ef->ddbstrtab; 1600 1601 if (*strtab == NULL) 1602 return (0); 1603 1604 return (ef->ddbstrcnt); 1605 }
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