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/11.1/sys/kern/link_elf.c 298069 2016-04-15 16:10:11Z pfg $"); 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 <sys/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 int elf_lookup(linker_file_t, Elf_Size, int, Elf_Addr *); 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 /* 321 * The kernel symbol table starts here. 322 */ 323 extern struct _dynamic _DYNAMIC; 324 325 static void 326 link_elf_error(const char *filename, const char *s) 327 { 328 if (filename == NULL) 329 printf("kldload: %s\n", s); 330 else 331 printf("kldload: %s: %s\n", filename, s); 332 } 333 334 static void 335 link_elf_invoke_ctors(caddr_t addr, size_t size) 336 { 337 void (**ctor)(void); 338 size_t i, cnt; 339 340 if (addr == NULL || size == 0) 341 return; 342 cnt = size / sizeof(*ctor); 343 ctor = (void *)addr; 344 for (i = 0; i < cnt; i++) { 345 if (ctor[i] != NULL) 346 (*ctor[i])(); 347 } 348 } 349 350 /* 351 * Actions performed after linking/loading both the preloaded kernel and any 352 * modules; whether preloaded or dynamicly loaded. 353 */ 354 static int 355 link_elf_link_common_finish(linker_file_t lf) 356 { 357 #ifdef GDB 358 elf_file_t ef = (elf_file_t)lf; 359 char *newfilename; 360 #endif 361 int error; 362 363 /* Notify MD code that a module is being loaded. */ 364 error = elf_cpu_load_file(lf); 365 if (error != 0) 366 return (error); 367 368 #ifdef GDB 369 GDB_STATE(RT_ADD); 370 ef->gdb.l_addr = lf->address; 371 newfilename = malloc(strlen(lf->filename) + 1, M_LINKER, M_WAITOK); 372 strcpy(newfilename, lf->filename); 373 ef->gdb.l_name = newfilename; 374 ef->gdb.l_ld = ef->dynamic; 375 link_elf_add_gdb(&ef->gdb); 376 GDB_STATE(RT_CONSISTENT); 377 #endif 378 379 /* Invoke .ctors */ 380 link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size); 381 return (0); 382 } 383 384 extern vm_offset_t __startkernel; 385 386 static void 387 link_elf_init(void* arg) 388 { 389 Elf_Dyn *dp; 390 Elf_Addr *ctors_addrp; 391 Elf_Size *ctors_sizep; 392 caddr_t modptr, baseptr, sizeptr; 393 elf_file_t ef; 394 char *modname; 395 396 linker_add_class(&link_elf_class); 397 398 dp = (Elf_Dyn *)&_DYNAMIC; 399 modname = NULL; 400 modptr = preload_search_by_type("elf" __XSTRING(__ELF_WORD_SIZE) " kernel"); 401 if (modptr == NULL) 402 modptr = preload_search_by_type("elf kernel"); 403 modname = (char *)preload_search_info(modptr, MODINFO_NAME); 404 if (modname == NULL) 405 modname = "kernel"; 406 linker_kernel_file = linker_make_file(modname, &link_elf_class); 407 if (linker_kernel_file == NULL) 408 panic("%s: Can't create linker structures for kernel", 409 __func__); 410 411 ef = (elf_file_t) linker_kernel_file; 412 ef->preloaded = 1; 413 #ifdef __powerpc__ 414 ef->address = (caddr_t) (__startkernel - KERNBASE); 415 #else 416 ef->address = 0; 417 #endif 418 #ifdef SPARSE_MAPPING 419 ef->object = 0; 420 #endif 421 ef->dynamic = dp; 422 423 if (dp != NULL) 424 parse_dynamic(ef); 425 linker_kernel_file->address += KERNBASE; 426 linker_kernel_file->size = -(intptr_t)linker_kernel_file->address; 427 428 if (modptr != NULL) { 429 ef->modptr = modptr; 430 baseptr = preload_search_info(modptr, MODINFO_ADDR); 431 if (baseptr != NULL) 432 linker_kernel_file->address = *(caddr_t *)baseptr; 433 sizeptr = preload_search_info(modptr, MODINFO_SIZE); 434 if (sizeptr != NULL) 435 linker_kernel_file->size = *(size_t *)sizeptr; 436 ctors_addrp = (Elf_Addr *)preload_search_info(modptr, 437 MODINFO_METADATA | MODINFOMD_CTORS_ADDR); 438 ctors_sizep = (Elf_Size *)preload_search_info(modptr, 439 MODINFO_METADATA | MODINFOMD_CTORS_SIZE); 440 if (ctors_addrp != NULL && ctors_sizep != NULL) { 441 linker_kernel_file->ctors_addr = ef->address + 442 *ctors_addrp; 443 linker_kernel_file->ctors_size = *ctors_sizep; 444 } 445 } 446 (void)link_elf_preload_parse_symbols(ef); 447 448 #ifdef GDB 449 r_debug.r_map = NULL; 450 r_debug.r_brk = r_debug_state; 451 r_debug.r_state = RT_CONSISTENT; 452 #endif 453 454 (void)link_elf_link_common_finish(linker_kernel_file); 455 linker_kernel_file->flags |= LINKER_FILE_LINKED; 456 TAILQ_INIT(&set_pcpu_list); 457 #ifdef VIMAGE 458 TAILQ_INIT(&set_vnet_list); 459 #endif 460 } 461 462 SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_THIRD, link_elf_init, 0); 463 464 static int 465 link_elf_preload_parse_symbols(elf_file_t ef) 466 { 467 caddr_t pointer; 468 caddr_t ssym, esym, base; 469 caddr_t strtab; 470 int strcnt; 471 Elf_Sym *symtab; 472 int symcnt; 473 474 if (ef->modptr == NULL) 475 return (0); 476 pointer = preload_search_info(ef->modptr, 477 MODINFO_METADATA | MODINFOMD_SSYM); 478 if (pointer == NULL) 479 return (0); 480 ssym = *(caddr_t *)pointer; 481 pointer = preload_search_info(ef->modptr, 482 MODINFO_METADATA | MODINFOMD_ESYM); 483 if (pointer == NULL) 484 return (0); 485 esym = *(caddr_t *)pointer; 486 487 base = ssym; 488 489 symcnt = *(long *)base; 490 base += sizeof(long); 491 symtab = (Elf_Sym *)base; 492 base += roundup(symcnt, sizeof(long)); 493 494 if (base > esym || base < ssym) { 495 printf("Symbols are corrupt!\n"); 496 return (EINVAL); 497 } 498 499 strcnt = *(long *)base; 500 base += sizeof(long); 501 strtab = base; 502 base += roundup(strcnt, sizeof(long)); 503 504 if (base > esym || base < ssym) { 505 printf("Symbols are corrupt!\n"); 506 return (EINVAL); 507 } 508 509 ef->ddbsymtab = symtab; 510 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym); 511 ef->ddbstrtab = strtab; 512 ef->ddbstrcnt = strcnt; 513 514 return (0); 515 } 516 517 static int 518 parse_dynamic(elf_file_t ef) 519 { 520 Elf_Dyn *dp; 521 int plttype = DT_REL; 522 523 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) { 524 switch (dp->d_tag) { 525 case DT_HASH: 526 { 527 /* From src/libexec/rtld-elf/rtld.c */ 528 const Elf_Hashelt *hashtab = (const Elf_Hashelt *) 529 (ef->address + dp->d_un.d_ptr); 530 ef->nbuckets = hashtab[0]; 531 ef->nchains = hashtab[1]; 532 ef->buckets = hashtab + 2; 533 ef->chains = ef->buckets + ef->nbuckets; 534 break; 535 } 536 case DT_STRTAB: 537 ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr); 538 break; 539 case DT_STRSZ: 540 ef->strsz = dp->d_un.d_val; 541 break; 542 case DT_SYMTAB: 543 ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr); 544 break; 545 case DT_SYMENT: 546 if (dp->d_un.d_val != sizeof(Elf_Sym)) 547 return (ENOEXEC); 548 break; 549 case DT_PLTGOT: 550 ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr); 551 break; 552 case DT_REL: 553 ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr); 554 break; 555 case DT_RELSZ: 556 ef->relsize = dp->d_un.d_val; 557 break; 558 case DT_RELENT: 559 if (dp->d_un.d_val != sizeof(Elf_Rel)) 560 return (ENOEXEC); 561 break; 562 case DT_JMPREL: 563 ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr); 564 break; 565 case DT_PLTRELSZ: 566 ef->pltrelsize = dp->d_un.d_val; 567 break; 568 case DT_RELA: 569 ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr); 570 break; 571 case DT_RELASZ: 572 ef->relasize = dp->d_un.d_val; 573 break; 574 case DT_RELAENT: 575 if (dp->d_un.d_val != sizeof(Elf_Rela)) 576 return (ENOEXEC); 577 break; 578 case DT_PLTREL: 579 plttype = dp->d_un.d_val; 580 if (plttype != DT_REL && plttype != DT_RELA) 581 return (ENOEXEC); 582 break; 583 #ifdef GDB 584 case DT_DEBUG: 585 dp->d_un.d_ptr = (Elf_Addr)&r_debug; 586 break; 587 #endif 588 } 589 } 590 591 if (plttype == DT_RELA) { 592 ef->pltrela = (const Elf_Rela *)ef->pltrel; 593 ef->pltrel = NULL; 594 ef->pltrelasize = ef->pltrelsize; 595 ef->pltrelsize = 0; 596 } 597 598 ef->ddbsymtab = ef->symtab; 599 ef->ddbsymcnt = ef->nchains; 600 ef->ddbstrtab = ef->strtab; 601 ef->ddbstrcnt = ef->strsz; 602 603 return (0); 604 } 605 606 static int 607 parse_dpcpu(elf_file_t ef) 608 { 609 int count; 610 int error; 611 612 ef->pcpu_start = 0; 613 ef->pcpu_stop = 0; 614 error = link_elf_lookup_set(&ef->lf, "pcpu", (void ***)&ef->pcpu_start, 615 (void ***)&ef->pcpu_stop, &count); 616 /* Error just means there is no pcpu set to relocate. */ 617 if (error != 0) 618 return (0); 619 count *= sizeof(void *); 620 /* 621 * Allocate space in the primary pcpu area. Copy in our 622 * initialization from the data section and then initialize 623 * all per-cpu storage from that. 624 */ 625 ef->pcpu_base = (Elf_Addr)(uintptr_t)dpcpu_alloc(count); 626 if (ef->pcpu_base == 0) 627 return (ENOSPC); 628 memcpy((void *)ef->pcpu_base, (void *)ef->pcpu_start, count); 629 dpcpu_copy((void *)ef->pcpu_base, count); 630 elf_set_add(&set_pcpu_list, ef->pcpu_start, ef->pcpu_stop, 631 ef->pcpu_base); 632 633 return (0); 634 } 635 636 #ifdef VIMAGE 637 static int 638 parse_vnet(elf_file_t ef) 639 { 640 int count; 641 int error; 642 643 ef->vnet_start = 0; 644 ef->vnet_stop = 0; 645 error = link_elf_lookup_set(&ef->lf, "vnet", (void ***)&ef->vnet_start, 646 (void ***)&ef->vnet_stop, &count); 647 /* Error just means there is no vnet data set to relocate. */ 648 if (error != 0) 649 return (0); 650 count *= sizeof(void *); 651 /* 652 * Allocate space in the primary vnet area. Copy in our 653 * initialization from the data section and then initialize 654 * all per-vnet storage from that. 655 */ 656 ef->vnet_base = (Elf_Addr)(uintptr_t)vnet_data_alloc(count); 657 if (ef->vnet_base == 0) 658 return (ENOSPC); 659 memcpy((void *)ef->vnet_base, (void *)ef->vnet_start, count); 660 vnet_data_copy((void *)ef->vnet_base, count); 661 elf_set_add(&set_vnet_list, ef->vnet_start, ef->vnet_stop, 662 ef->vnet_base); 663 664 return (0); 665 } 666 #endif 667 668 static int 669 link_elf_link_preload(linker_class_t cls, 670 const char* filename, linker_file_t *result) 671 { 672 Elf_Addr *ctors_addrp; 673 Elf_Size *ctors_sizep; 674 caddr_t modptr, baseptr, sizeptr, dynptr; 675 char *type; 676 elf_file_t ef; 677 linker_file_t lf; 678 int error; 679 vm_offset_t dp; 680 681 /* Look to see if we have the file preloaded */ 682 modptr = preload_search_by_name(filename); 683 if (modptr == NULL) 684 return (ENOENT); 685 686 type = (char *)preload_search_info(modptr, MODINFO_TYPE); 687 baseptr = preload_search_info(modptr, MODINFO_ADDR); 688 sizeptr = preload_search_info(modptr, MODINFO_SIZE); 689 dynptr = preload_search_info(modptr, 690 MODINFO_METADATA | MODINFOMD_DYNAMIC); 691 if (type == NULL || 692 (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) " module") != 0 && 693 strcmp(type, "elf module") != 0)) 694 return (EFTYPE); 695 if (baseptr == NULL || sizeptr == NULL || dynptr == NULL) 696 return (EINVAL); 697 698 lf = linker_make_file(filename, &link_elf_class); 699 if (lf == NULL) 700 return (ENOMEM); 701 702 ef = (elf_file_t) lf; 703 ef->preloaded = 1; 704 ef->modptr = modptr; 705 ef->address = *(caddr_t *)baseptr; 706 #ifdef SPARSE_MAPPING 707 ef->object = 0; 708 #endif 709 dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr; 710 ef->dynamic = (Elf_Dyn *)dp; 711 lf->address = ef->address; 712 lf->size = *(size_t *)sizeptr; 713 714 ctors_addrp = (Elf_Addr *)preload_search_info(modptr, 715 MODINFO_METADATA | MODINFOMD_CTORS_ADDR); 716 ctors_sizep = (Elf_Size *)preload_search_info(modptr, 717 MODINFO_METADATA | MODINFOMD_CTORS_SIZE); 718 if (ctors_addrp != NULL && ctors_sizep != NULL) { 719 lf->ctors_addr = ef->address + *ctors_addrp; 720 lf->ctors_size = *ctors_sizep; 721 } 722 723 error = parse_dynamic(ef); 724 if (error == 0) 725 error = parse_dpcpu(ef); 726 #ifdef VIMAGE 727 if (error == 0) 728 error = parse_vnet(ef); 729 #endif 730 if (error != 0) { 731 linker_file_unload(lf, LINKER_UNLOAD_FORCE); 732 return (error); 733 } 734 link_elf_reloc_local(lf); 735 *result = lf; 736 return (0); 737 } 738 739 static int 740 link_elf_link_preload_finish(linker_file_t lf) 741 { 742 elf_file_t ef; 743 int error; 744 745 ef = (elf_file_t) lf; 746 error = relocate_file(ef); 747 if (error != 0) 748 return (error); 749 (void)link_elf_preload_parse_symbols(ef); 750 751 return (link_elf_link_common_finish(lf)); 752 } 753 754 static int 755 link_elf_load_file(linker_class_t cls, const char* filename, 756 linker_file_t* result) 757 { 758 struct nameidata nd; 759 struct thread* td = curthread; /* XXX */ 760 Elf_Ehdr *hdr; 761 caddr_t firstpage; 762 int nbytes, i; 763 Elf_Phdr *phdr; 764 Elf_Phdr *phlimit; 765 Elf_Phdr *segs[MAXSEGS]; 766 int nsegs; 767 Elf_Phdr *phdyn; 768 Elf_Phdr *phphdr; 769 caddr_t mapbase; 770 size_t mapsize; 771 Elf_Off base_offset; 772 Elf_Addr base_vaddr; 773 Elf_Addr base_vlimit; 774 int error = 0; 775 ssize_t resid; 776 int flags; 777 elf_file_t ef; 778 linker_file_t lf; 779 Elf_Shdr *shdr; 780 int symtabindex; 781 int symstrindex; 782 int shstrindex; 783 int symcnt; 784 int strcnt; 785 char *shstrs; 786 787 shdr = NULL; 788 lf = NULL; 789 shstrs = NULL; 790 791 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td); 792 flags = FREAD; 793 error = vn_open(&nd, &flags, 0, NULL); 794 if (error != 0) 795 return (error); 796 NDFREE(&nd, NDF_ONLY_PNBUF); 797 if (nd.ni_vp->v_type != VREG) { 798 error = ENOEXEC; 799 firstpage = NULL; 800 goto out; 801 } 802 #ifdef MAC 803 error = mac_kld_check_load(curthread->td_ucred, nd.ni_vp); 804 if (error != 0) { 805 firstpage = NULL; 806 goto out; 807 } 808 #endif 809 810 /* 811 * Read the elf header from the file. 812 */ 813 firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK); 814 hdr = (Elf_Ehdr *)firstpage; 815 error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0, 816 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 817 &resid, td); 818 nbytes = PAGE_SIZE - resid; 819 if (error != 0) 820 goto out; 821 822 if (!IS_ELF(*hdr)) { 823 error = ENOEXEC; 824 goto out; 825 } 826 827 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS || 828 hdr->e_ident[EI_DATA] != ELF_TARG_DATA) { 829 link_elf_error(filename, "Unsupported file layout"); 830 error = ENOEXEC; 831 goto out; 832 } 833 if (hdr->e_ident[EI_VERSION] != EV_CURRENT || 834 hdr->e_version != EV_CURRENT) { 835 link_elf_error(filename, "Unsupported file version"); 836 error = ENOEXEC; 837 goto out; 838 } 839 if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) { 840 error = ENOSYS; 841 goto out; 842 } 843 if (hdr->e_machine != ELF_TARG_MACH) { 844 link_elf_error(filename, "Unsupported machine"); 845 error = ENOEXEC; 846 goto out; 847 } 848 849 /* 850 * We rely on the program header being in the first page. 851 * This is not strictly required by the ABI specification, but 852 * it seems to always true in practice. And, it simplifies 853 * things considerably. 854 */ 855 if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) && 856 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) && 857 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes))) 858 link_elf_error(filename, "Unreadable program headers"); 859 860 /* 861 * Scan the program header entries, and save key information. 862 * 863 * We rely on there being exactly two load segments, text and data, 864 * in that order. 865 */ 866 phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff); 867 phlimit = phdr + hdr->e_phnum; 868 nsegs = 0; 869 phdyn = NULL; 870 phphdr = NULL; 871 while (phdr < phlimit) { 872 switch (phdr->p_type) { 873 case PT_LOAD: 874 if (nsegs == MAXSEGS) { 875 link_elf_error(filename, "Too many sections"); 876 error = ENOEXEC; 877 goto out; 878 } 879 /* 880 * XXX: We just trust they come in right order ?? 881 */ 882 segs[nsegs] = phdr; 883 ++nsegs; 884 break; 885 886 case PT_PHDR: 887 phphdr = phdr; 888 break; 889 890 case PT_DYNAMIC: 891 phdyn = phdr; 892 break; 893 894 case PT_INTERP: 895 error = ENOSYS; 896 goto out; 897 } 898 899 ++phdr; 900 } 901 if (phdyn == NULL) { 902 link_elf_error(filename, "Object is not dynamically-linked"); 903 error = ENOEXEC; 904 goto out; 905 } 906 if (nsegs == 0) { 907 link_elf_error(filename, "No sections"); 908 error = ENOEXEC; 909 goto out; 910 } 911 912 /* 913 * Allocate the entire address space of the object, to stake 914 * out our contiguous region, and to establish the base 915 * address for relocation. 916 */ 917 base_offset = trunc_page(segs[0]->p_offset); 918 base_vaddr = trunc_page(segs[0]->p_vaddr); 919 base_vlimit = round_page(segs[nsegs - 1]->p_vaddr + 920 segs[nsegs - 1]->p_memsz); 921 mapsize = base_vlimit - base_vaddr; 922 923 lf = linker_make_file(filename, &link_elf_class); 924 if (lf == NULL) { 925 error = ENOMEM; 926 goto out; 927 } 928 929 ef = (elf_file_t) lf; 930 #ifdef SPARSE_MAPPING 931 ef->object = vm_object_allocate(OBJT_DEFAULT, mapsize >> PAGE_SHIFT); 932 if (ef->object == NULL) { 933 error = ENOMEM; 934 goto out; 935 } 936 ef->address = (caddr_t) vm_map_min(kernel_map); 937 error = vm_map_find(kernel_map, ef->object, 0, 938 (vm_offset_t *) &ef->address, mapsize, 0, VMFS_OPTIMAL_SPACE, 939 VM_PROT_ALL, VM_PROT_ALL, 0); 940 if (error != 0) { 941 vm_object_deallocate(ef->object); 942 ef->object = 0; 943 goto out; 944 } 945 #else 946 ef->address = malloc(mapsize, M_LINKER, M_WAITOK); 947 #endif 948 mapbase = ef->address; 949 950 /* 951 * Read the text and data sections and zero the bss. 952 */ 953 for (i = 0; i < nsegs; i++) { 954 caddr_t segbase = mapbase + segs[i]->p_vaddr - base_vaddr; 955 error = vn_rdwr(UIO_READ, nd.ni_vp, 956 segbase, segs[i]->p_filesz, segs[i]->p_offset, 957 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 958 &resid, td); 959 if (error != 0) 960 goto out; 961 bzero(segbase + segs[i]->p_filesz, 962 segs[i]->p_memsz - segs[i]->p_filesz); 963 964 #ifdef SPARSE_MAPPING 965 /* 966 * Wire down the pages 967 */ 968 error = vm_map_wire(kernel_map, 969 (vm_offset_t) segbase, 970 (vm_offset_t) segbase + segs[i]->p_memsz, 971 VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES); 972 if (error != KERN_SUCCESS) { 973 error = ENOMEM; 974 goto out; 975 } 976 #endif 977 } 978 979 #ifdef GPROF 980 /* Update profiling information with the new text segment. */ 981 mtx_lock(&Giant); 982 kmupetext((uintfptr_t)(mapbase + segs[0]->p_vaddr - base_vaddr + 983 segs[0]->p_memsz)); 984 mtx_unlock(&Giant); 985 #endif 986 987 ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr); 988 989 lf->address = ef->address; 990 lf->size = mapsize; 991 992 error = parse_dynamic(ef); 993 if (error != 0) 994 goto out; 995 error = parse_dpcpu(ef); 996 if (error != 0) 997 goto out; 998 #ifdef VIMAGE 999 error = parse_vnet(ef); 1000 if (error != 0) 1001 goto out; 1002 #endif 1003 link_elf_reloc_local(lf); 1004 1005 VOP_UNLOCK(nd.ni_vp, 0); 1006 error = linker_load_dependencies(lf); 1007 vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY); 1008 if (error != 0) 1009 goto out; 1010 error = relocate_file(ef); 1011 if (error != 0) 1012 goto out; 1013 1014 /* 1015 * Try and load the symbol table if it's present. (you can 1016 * strip it!) 1017 */ 1018 nbytes = hdr->e_shnum * hdr->e_shentsize; 1019 if (nbytes == 0 || hdr->e_shoff == 0) 1020 goto nosyms; 1021 shdr = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO); 1022 error = vn_rdwr(UIO_READ, nd.ni_vp, 1023 (caddr_t)shdr, nbytes, hdr->e_shoff, 1024 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1025 &resid, td); 1026 if (error != 0) 1027 goto out; 1028 1029 /* Read section string table */ 1030 shstrindex = hdr->e_shstrndx; 1031 if (shstrindex != 0 && shdr[shstrindex].sh_type == SHT_STRTAB && 1032 shdr[shstrindex].sh_size != 0) { 1033 nbytes = shdr[shstrindex].sh_size; 1034 shstrs = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO); 1035 error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)shstrs, nbytes, 1036 shdr[shstrindex].sh_offset, UIO_SYSSPACE, IO_NODELOCKED, 1037 td->td_ucred, NOCRED, &resid, td); 1038 if (error) 1039 goto out; 1040 } 1041 1042 symtabindex = -1; 1043 symstrindex = -1; 1044 for (i = 0; i < hdr->e_shnum; i++) { 1045 if (shdr[i].sh_type == SHT_SYMTAB) { 1046 symtabindex = i; 1047 symstrindex = shdr[i].sh_link; 1048 } else if (shstrs != NULL && shdr[i].sh_name != 0 && 1049 strcmp(shstrs + shdr[i].sh_name, ".ctors") == 0) { 1050 /* Record relocated address and size of .ctors. */ 1051 lf->ctors_addr = mapbase + shdr[i].sh_addr - base_vaddr; 1052 lf->ctors_size = shdr[i].sh_size; 1053 } 1054 } 1055 if (symtabindex < 0 || symstrindex < 0) 1056 goto nosyms; 1057 1058 symcnt = shdr[symtabindex].sh_size; 1059 ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK); 1060 strcnt = shdr[symstrindex].sh_size; 1061 ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK); 1062 1063 error = vn_rdwr(UIO_READ, nd.ni_vp, 1064 ef->symbase, symcnt, shdr[symtabindex].sh_offset, 1065 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1066 &resid, td); 1067 if (error != 0) 1068 goto out; 1069 error = vn_rdwr(UIO_READ, nd.ni_vp, 1070 ef->strbase, strcnt, shdr[symstrindex].sh_offset, 1071 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1072 &resid, td); 1073 if (error != 0) 1074 goto out; 1075 1076 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym); 1077 ef->ddbsymtab = (const Elf_Sym *)ef->symbase; 1078 ef->ddbstrcnt = strcnt; 1079 ef->ddbstrtab = ef->strbase; 1080 1081 nosyms: 1082 error = link_elf_link_common_finish(lf); 1083 if (error != 0) 1084 goto out; 1085 1086 *result = lf; 1087 1088 out: 1089 VOP_UNLOCK(nd.ni_vp, 0); 1090 vn_close(nd.ni_vp, FREAD, td->td_ucred, td); 1091 if (error != 0 && lf != NULL) 1092 linker_file_unload(lf, LINKER_UNLOAD_FORCE); 1093 free(shdr, M_LINKER); 1094 free(firstpage, M_LINKER); 1095 free(shstrs, M_LINKER); 1096 1097 return (error); 1098 } 1099 1100 Elf_Addr 1101 elf_relocaddr(linker_file_t lf, Elf_Addr x) 1102 { 1103 elf_file_t ef; 1104 1105 ef = (elf_file_t)lf; 1106 if (x >= ef->pcpu_start && x < ef->pcpu_stop) 1107 return ((x - ef->pcpu_start) + ef->pcpu_base); 1108 #ifdef VIMAGE 1109 if (x >= ef->vnet_start && x < ef->vnet_stop) 1110 return ((x - ef->vnet_start) + ef->vnet_base); 1111 #endif 1112 return (x); 1113 } 1114 1115 1116 static void 1117 link_elf_unload_file(linker_file_t file) 1118 { 1119 elf_file_t ef = (elf_file_t) file; 1120 1121 if (ef->pcpu_base != 0) { 1122 dpcpu_free((void *)ef->pcpu_base, 1123 ef->pcpu_stop - ef->pcpu_start); 1124 elf_set_delete(&set_pcpu_list, ef->pcpu_start); 1125 } 1126 #ifdef VIMAGE 1127 if (ef->vnet_base != 0) { 1128 vnet_data_free((void *)ef->vnet_base, 1129 ef->vnet_stop - ef->vnet_start); 1130 elf_set_delete(&set_vnet_list, ef->vnet_start); 1131 } 1132 #endif 1133 #ifdef GDB 1134 if (ef->gdb.l_ld != NULL) { 1135 GDB_STATE(RT_DELETE); 1136 free((void *)(uintptr_t)ef->gdb.l_name, M_LINKER); 1137 link_elf_delete_gdb(&ef->gdb); 1138 GDB_STATE(RT_CONSISTENT); 1139 } 1140 #endif 1141 1142 /* Notify MD code that a module is being unloaded. */ 1143 elf_cpu_unload_file(file); 1144 1145 if (ef->preloaded) { 1146 link_elf_unload_preload(file); 1147 return; 1148 } 1149 1150 #ifdef SPARSE_MAPPING 1151 if (ef->object != NULL) { 1152 vm_map_remove(kernel_map, (vm_offset_t) ef->address, 1153 (vm_offset_t) ef->address 1154 + (ef->object->size << PAGE_SHIFT)); 1155 } 1156 #else 1157 free(ef->address, M_LINKER); 1158 #endif 1159 free(ef->symbase, M_LINKER); 1160 free(ef->strbase, M_LINKER); 1161 free(ef->ctftab, M_LINKER); 1162 free(ef->ctfoff, M_LINKER); 1163 free(ef->typoff, M_LINKER); 1164 } 1165 1166 static void 1167 link_elf_unload_preload(linker_file_t file) 1168 { 1169 if (file->filename != NULL) 1170 preload_delete_name(file->filename); 1171 } 1172 1173 static const char * 1174 symbol_name(elf_file_t ef, Elf_Size r_info) 1175 { 1176 const Elf_Sym *ref; 1177 1178 if (ELF_R_SYM(r_info)) { 1179 ref = ef->symtab + ELF_R_SYM(r_info); 1180 return (ef->strtab + ref->st_name); 1181 } 1182 return (NULL); 1183 } 1184 1185 static int 1186 relocate_file(elf_file_t ef) 1187 { 1188 const Elf_Rel *rellim; 1189 const Elf_Rel *rel; 1190 const Elf_Rela *relalim; 1191 const Elf_Rela *rela; 1192 const char *symname; 1193 1194 /* Perform relocations without addend if there are any: */ 1195 rel = ef->rel; 1196 if (rel != NULL) { 1197 rellim = (const Elf_Rel *) 1198 ((const char *)ef->rel + ef->relsize); 1199 while (rel < rellim) { 1200 if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rel, 1201 ELF_RELOC_REL, elf_lookup)) { 1202 symname = symbol_name(ef, rel->r_info); 1203 printf("link_elf: symbol %s undefined\n", symname); 1204 return (ENOENT); 1205 } 1206 rel++; 1207 } 1208 } 1209 1210 /* Perform relocations with addend if there are any: */ 1211 rela = ef->rela; 1212 if (rela != NULL) { 1213 relalim = (const Elf_Rela *) 1214 ((const char *)ef->rela + ef->relasize); 1215 while (rela < relalim) { 1216 if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rela, 1217 ELF_RELOC_RELA, elf_lookup)) { 1218 symname = symbol_name(ef, rela->r_info); 1219 printf("link_elf: symbol %s undefined\n", 1220 symname); 1221 return (ENOENT); 1222 } 1223 rela++; 1224 } 1225 } 1226 1227 /* Perform PLT relocations without addend if there are any: */ 1228 rel = ef->pltrel; 1229 if (rel != NULL) { 1230 rellim = (const Elf_Rel *) 1231 ((const char *)ef->pltrel + ef->pltrelsize); 1232 while (rel < rellim) { 1233 if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rel, 1234 ELF_RELOC_REL, elf_lookup)) { 1235 symname = symbol_name(ef, rel->r_info); 1236 printf("link_elf: symbol %s undefined\n", 1237 symname); 1238 return (ENOENT); 1239 } 1240 rel++; 1241 } 1242 } 1243 1244 /* Perform relocations with addend if there are any: */ 1245 rela = ef->pltrela; 1246 if (rela != NULL) { 1247 relalim = (const Elf_Rela *) 1248 ((const char *)ef->pltrela + ef->pltrelasize); 1249 while (rela < relalim) { 1250 if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rela, 1251 ELF_RELOC_RELA, elf_lookup)) { 1252 symname = symbol_name(ef, rela->r_info); 1253 printf("link_elf: symbol %s undefined\n", 1254 symname); 1255 return (ENOENT); 1256 } 1257 rela++; 1258 } 1259 } 1260 1261 return (0); 1262 } 1263 1264 /* 1265 * Hash function for symbol table lookup. Don't even think about changing 1266 * this. It is specified by the System V ABI. 1267 */ 1268 static unsigned long 1269 elf_hash(const char *name) 1270 { 1271 const unsigned char *p = (const unsigned char *) name; 1272 unsigned long h = 0; 1273 unsigned long g; 1274 1275 while (*p != '\0') { 1276 h = (h << 4) + *p++; 1277 if ((g = h & 0xf0000000) != 0) 1278 h ^= g >> 24; 1279 h &= ~g; 1280 } 1281 return (h); 1282 } 1283 1284 static int 1285 link_elf_lookup_symbol(linker_file_t lf, const char* name, c_linker_sym_t* sym) 1286 { 1287 elf_file_t ef = (elf_file_t) lf; 1288 unsigned long symnum; 1289 const Elf_Sym* symp; 1290 const char *strp; 1291 unsigned long hash; 1292 int i; 1293 1294 /* If we don't have a hash, bail. */ 1295 if (ef->buckets == NULL || ef->nbuckets == 0) { 1296 printf("link_elf_lookup_symbol: missing symbol hash table\n"); 1297 return (ENOENT); 1298 } 1299 1300 /* First, search hashed global symbols */ 1301 hash = elf_hash(name); 1302 symnum = ef->buckets[hash % ef->nbuckets]; 1303 1304 while (symnum != STN_UNDEF) { 1305 if (symnum >= ef->nchains) { 1306 printf("%s: corrupt symbol table\n", __func__); 1307 return (ENOENT); 1308 } 1309 1310 symp = ef->symtab + symnum; 1311 if (symp->st_name == 0) { 1312 printf("%s: corrupt symbol table\n", __func__); 1313 return (ENOENT); 1314 } 1315 1316 strp = ef->strtab + symp->st_name; 1317 1318 if (strcmp(name, strp) == 0) { 1319 if (symp->st_shndx != SHN_UNDEF || 1320 (symp->st_value != 0 && 1321 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) { 1322 *sym = (c_linker_sym_t) symp; 1323 return (0); 1324 } 1325 return (ENOENT); 1326 } 1327 1328 symnum = ef->chains[symnum]; 1329 } 1330 1331 /* If we have not found it, look at the full table (if loaded) */ 1332 if (ef->symtab == ef->ddbsymtab) 1333 return (ENOENT); 1334 1335 /* Exhaustive search */ 1336 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1337 strp = ef->ddbstrtab + symp->st_name; 1338 if (strcmp(name, strp) == 0) { 1339 if (symp->st_shndx != SHN_UNDEF || 1340 (symp->st_value != 0 && 1341 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) { 1342 *sym = (c_linker_sym_t) symp; 1343 return (0); 1344 } 1345 return (ENOENT); 1346 } 1347 } 1348 1349 return (ENOENT); 1350 } 1351 1352 static int 1353 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, 1354 linker_symval_t *symval) 1355 { 1356 elf_file_t ef = (elf_file_t) lf; 1357 const Elf_Sym* es = (const Elf_Sym*) sym; 1358 1359 if (es >= ef->symtab && es < (ef->symtab + ef->nchains)) { 1360 symval->name = ef->strtab + es->st_name; 1361 symval->value = (caddr_t) ef->address + es->st_value; 1362 symval->size = es->st_size; 1363 return (0); 1364 } 1365 if (ef->symtab == ef->ddbsymtab) 1366 return (ENOENT); 1367 if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) { 1368 symval->name = ef->ddbstrtab + es->st_name; 1369 symval->value = (caddr_t) ef->address + es->st_value; 1370 symval->size = es->st_size; 1371 return (0); 1372 } 1373 return (ENOENT); 1374 } 1375 1376 static int 1377 link_elf_search_symbol(linker_file_t lf, caddr_t value, 1378 c_linker_sym_t *sym, long *diffp) 1379 { 1380 elf_file_t ef = (elf_file_t) lf; 1381 u_long off = (uintptr_t) (void *) value; 1382 u_long diff = off; 1383 u_long st_value; 1384 const Elf_Sym* es; 1385 const Elf_Sym* best = NULL; 1386 int i; 1387 1388 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) { 1389 if (es->st_name == 0) 1390 continue; 1391 st_value = es->st_value + (uintptr_t) (void *) ef->address; 1392 if (off >= st_value) { 1393 if (off - st_value < diff) { 1394 diff = off - st_value; 1395 best = es; 1396 if (diff == 0) 1397 break; 1398 } else if (off - st_value == diff) { 1399 best = es; 1400 } 1401 } 1402 } 1403 if (best == NULL) 1404 *diffp = off; 1405 else 1406 *diffp = diff; 1407 *sym = (c_linker_sym_t) best; 1408 1409 return (0); 1410 } 1411 1412 /* 1413 * Look up a linker set on an ELF system. 1414 */ 1415 static int 1416 link_elf_lookup_set(linker_file_t lf, const char *name, 1417 void ***startp, void ***stopp, int *countp) 1418 { 1419 c_linker_sym_t sym; 1420 linker_symval_t symval; 1421 char *setsym; 1422 void **start, **stop; 1423 int len, error = 0, count; 1424 1425 len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */ 1426 setsym = malloc(len, M_LINKER, M_WAITOK); 1427 1428 /* get address of first entry */ 1429 snprintf(setsym, len, "%s%s", "__start_set_", name); 1430 error = link_elf_lookup_symbol(lf, setsym, &sym); 1431 if (error != 0) 1432 goto out; 1433 link_elf_symbol_values(lf, sym, &symval); 1434 if (symval.value == 0) { 1435 error = ESRCH; 1436 goto out; 1437 } 1438 start = (void **)symval.value; 1439 1440 /* get address of last entry */ 1441 snprintf(setsym, len, "%s%s", "__stop_set_", name); 1442 error = link_elf_lookup_symbol(lf, setsym, &sym); 1443 if (error != 0) 1444 goto out; 1445 link_elf_symbol_values(lf, sym, &symval); 1446 if (symval.value == 0) { 1447 error = ESRCH; 1448 goto out; 1449 } 1450 stop = (void **)symval.value; 1451 1452 /* and the number of entries */ 1453 count = stop - start; 1454 1455 /* and copy out */ 1456 if (startp != NULL) 1457 *startp = start; 1458 if (stopp != NULL) 1459 *stopp = stop; 1460 if (countp != NULL) 1461 *countp = count; 1462 1463 out: 1464 free(setsym, M_LINKER); 1465 return (error); 1466 } 1467 1468 static int 1469 link_elf_each_function_name(linker_file_t file, 1470 int (*callback)(const char *, void *), void *opaque) 1471 { 1472 elf_file_t ef = (elf_file_t)file; 1473 const Elf_Sym *symp; 1474 int i, error; 1475 1476 /* Exhaustive search */ 1477 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1478 if (symp->st_value != 0 && 1479 ELF_ST_TYPE(symp->st_info) == STT_FUNC) { 1480 error = callback(ef->ddbstrtab + symp->st_name, opaque); 1481 if (error != 0) 1482 return (error); 1483 } 1484 } 1485 return (0); 1486 } 1487 1488 static int 1489 link_elf_each_function_nameval(linker_file_t file, 1490 linker_function_nameval_callback_t callback, void *opaque) 1491 { 1492 linker_symval_t symval; 1493 elf_file_t ef = (elf_file_t)file; 1494 const Elf_Sym* symp; 1495 int i, error; 1496 1497 /* Exhaustive search */ 1498 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1499 if (symp->st_value != 0 && 1500 ELF_ST_TYPE(symp->st_info) == STT_FUNC) { 1501 error = link_elf_symbol_values(file, 1502 (c_linker_sym_t) symp, &symval); 1503 if (error != 0) 1504 return (error); 1505 error = callback(file, i, &symval, opaque); 1506 if (error != 0) 1507 return (error); 1508 } 1509 } 1510 return (0); 1511 } 1512 1513 const Elf_Sym * 1514 elf_get_sym(linker_file_t lf, Elf_Size symidx) 1515 { 1516 elf_file_t ef = (elf_file_t)lf; 1517 1518 if (symidx >= ef->nchains) 1519 return (NULL); 1520 return (ef->symtab + symidx); 1521 } 1522 1523 const char * 1524 elf_get_symname(linker_file_t lf, Elf_Size symidx) 1525 { 1526 elf_file_t ef = (elf_file_t)lf; 1527 const Elf_Sym *sym; 1528 1529 if (symidx >= ef->nchains) 1530 return (NULL); 1531 sym = ef->symtab + symidx; 1532 return (ef->strtab + sym->st_name); 1533 } 1534 1535 /* 1536 * Symbol lookup function that can be used when the symbol index is known (ie 1537 * in relocations). It uses the symbol index instead of doing a fully fledged 1538 * hash table based lookup when such is valid. For example for local symbols. 1539 * This is not only more efficient, it's also more correct. It's not always 1540 * the case that the symbol can be found through the hash table. 1541 */ 1542 static int 1543 elf_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res) 1544 { 1545 elf_file_t ef = (elf_file_t)lf; 1546 const Elf_Sym *sym; 1547 const char *symbol; 1548 Elf_Addr addr, start, base; 1549 1550 /* Don't even try to lookup the symbol if the index is bogus. */ 1551 if (symidx >= ef->nchains) { 1552 *res = 0; 1553 return (EINVAL); 1554 } 1555 1556 sym = ef->symtab + symidx; 1557 1558 /* 1559 * Don't do a full lookup when the symbol is local. It may even 1560 * fail because it may not be found through the hash table. 1561 */ 1562 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) { 1563 /* Force lookup failure when we have an insanity. */ 1564 if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0) { 1565 *res = 0; 1566 return (EINVAL); 1567 } 1568 *res = ((Elf_Addr)ef->address + sym->st_value); 1569 return (0); 1570 } 1571 1572 /* 1573 * XXX we can avoid doing a hash table based lookup for global 1574 * symbols as well. This however is not always valid, so we'll 1575 * just do it the hard way for now. Performance tweaks can 1576 * always be added. 1577 */ 1578 1579 symbol = ef->strtab + sym->st_name; 1580 1581 /* Force a lookup failure if the symbol name is bogus. */ 1582 if (*symbol == 0) { 1583 *res = 0; 1584 return (EINVAL); 1585 } 1586 1587 addr = ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps)); 1588 if (addr == 0 && ELF_ST_BIND(sym->st_info) != STB_WEAK) { 1589 *res = 0; 1590 return (EINVAL); 1591 } 1592 1593 if (elf_set_find(&set_pcpu_list, addr, &start, &base)) 1594 addr = addr - start + base; 1595 #ifdef VIMAGE 1596 else if (elf_set_find(&set_vnet_list, addr, &start, &base)) 1597 addr = addr - start + base; 1598 #endif 1599 *res = addr; 1600 return (0); 1601 } 1602 1603 static void 1604 link_elf_reloc_local(linker_file_t lf) 1605 { 1606 const Elf_Rel *rellim; 1607 const Elf_Rel *rel; 1608 const Elf_Rela *relalim; 1609 const Elf_Rela *rela; 1610 elf_file_t ef = (elf_file_t)lf; 1611 1612 /* Perform relocations without addend if there are any: */ 1613 if ((rel = ef->rel) != NULL) { 1614 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize); 1615 while (rel < rellim) { 1616 elf_reloc_local(lf, (Elf_Addr)ef->address, rel, 1617 ELF_RELOC_REL, elf_lookup); 1618 rel++; 1619 } 1620 } 1621 1622 /* Perform relocations with addend if there are any: */ 1623 if ((rela = ef->rela) != NULL) { 1624 relalim = (const Elf_Rela *) 1625 ((const char *)ef->rela + ef->relasize); 1626 while (rela < relalim) { 1627 elf_reloc_local(lf, (Elf_Addr)ef->address, rela, 1628 ELF_RELOC_RELA, elf_lookup); 1629 rela++; 1630 } 1631 } 1632 } 1633 1634 static long 1635 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab) 1636 { 1637 elf_file_t ef = (elf_file_t)lf; 1638 1639 *symtab = ef->ddbsymtab; 1640 1641 if (*symtab == NULL) 1642 return (0); 1643 1644 return (ef->ddbsymcnt); 1645 } 1646 1647 static long 1648 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab) 1649 { 1650 elf_file_t ef = (elf_file_t)lf; 1651 1652 *strtab = ef->ddbstrtab; 1653 1654 if (*strtab == NULL) 1655 return (0); 1656 1657 return (ef->ddbstrcnt); 1658 }
Cache object: 5e9ac9b4a006665ec2ebe92f2b944c16
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