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 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 1998-2000 Doug Rabson 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #include <sys/cdefs.h> 30 __FBSDID("$FreeBSD$"); 31 32 #include "opt_ddb.h" 33 #include "opt_gdb.h" 34 35 #include <sys/param.h> 36 #include <sys/systm.h> 37 #ifdef GPROF 38 #include <sys/gmon.h> 39 #endif 40 #include <sys/kernel.h> 41 #include <sys/lock.h> 42 #include <sys/malloc.h> 43 #ifdef SPARSE_MAPPING 44 #include <sys/mman.h> 45 #endif 46 #include <sys/mutex.h> 47 #include <sys/mount.h> 48 #include <sys/pcpu.h> 49 #include <sys/proc.h> 50 #include <sys/namei.h> 51 #include <sys/fcntl.h> 52 #include <sys/vnode.h> 53 #include <sys/linker.h> 54 55 #include <machine/elf.h> 56 57 #include <net/vnet.h> 58 59 #include <security/mac/mac_framework.h> 60 61 #include <vm/vm.h> 62 #include <vm/vm_param.h> 63 #ifdef SPARSE_MAPPING 64 #include <vm/vm_object.h> 65 #include <vm/vm_kern.h> 66 #include <vm/vm_extern.h> 67 #endif 68 #include <vm/pmap.h> 69 #include <vm/vm_map.h> 70 71 #include <sys/link_elf.h> 72 73 #include "linker_if.h" 74 75 #define MAXSEGS 4 76 77 typedef struct elf_file { 78 struct linker_file lf; /* Common fields */ 79 int preloaded; /* Was file pre-loaded */ 80 caddr_t address; /* Relocation address */ 81 #ifdef SPARSE_MAPPING 82 vm_object_t object; /* VM object to hold file pages */ 83 #endif 84 Elf_Dyn *dynamic; /* Symbol table etc. */ 85 Elf_Hashelt nbuckets; /* DT_HASH info */ 86 Elf_Hashelt nchains; 87 const Elf_Hashelt *buckets; 88 const Elf_Hashelt *chains; 89 caddr_t hash; 90 caddr_t strtab; /* DT_STRTAB */ 91 int strsz; /* DT_STRSZ */ 92 const Elf_Sym *symtab; /* DT_SYMTAB */ 93 Elf_Addr *got; /* DT_PLTGOT */ 94 const Elf_Rel *pltrel; /* DT_JMPREL */ 95 int pltrelsize; /* DT_PLTRELSZ */ 96 const Elf_Rela *pltrela; /* DT_JMPREL */ 97 int pltrelasize; /* DT_PLTRELSZ */ 98 const Elf_Rel *rel; /* DT_REL */ 99 int relsize; /* DT_RELSZ */ 100 const Elf_Rela *rela; /* DT_RELA */ 101 int relasize; /* DT_RELASZ */ 102 caddr_t modptr; 103 const Elf_Sym *ddbsymtab; /* The symbol table we are using */ 104 long ddbsymcnt; /* Number of symbols */ 105 caddr_t ddbstrtab; /* String table */ 106 long ddbstrcnt; /* number of bytes in string table */ 107 caddr_t symbase; /* malloc'ed symbold base */ 108 caddr_t strbase; /* malloc'ed string base */ 109 caddr_t ctftab; /* CTF table */ 110 long ctfcnt; /* number of bytes in CTF table */ 111 caddr_t ctfoff; /* CTF offset table */ 112 caddr_t typoff; /* Type offset table */ 113 long typlen; /* Number of type entries. */ 114 Elf_Addr pcpu_start; /* Pre-relocation pcpu set start. */ 115 Elf_Addr pcpu_stop; /* Pre-relocation pcpu set stop. */ 116 Elf_Addr pcpu_base; /* Relocated pcpu set address. */ 117 #ifdef VIMAGE 118 Elf_Addr vnet_start; /* Pre-relocation vnet set start. */ 119 Elf_Addr vnet_stop; /* Pre-relocation vnet set stop. */ 120 Elf_Addr vnet_base; /* Relocated vnet set address. */ 121 #endif 122 #ifdef GDB 123 struct link_map gdb; /* hooks for gdb */ 124 #endif 125 } *elf_file_t; 126 127 struct elf_set { 128 Elf_Addr es_start; 129 Elf_Addr es_stop; 130 Elf_Addr es_base; 131 TAILQ_ENTRY(elf_set) es_link; 132 }; 133 134 TAILQ_HEAD(elf_set_head, elf_set); 135 136 #include <kern/kern_ctf.c> 137 138 static int link_elf_link_common_finish(linker_file_t); 139 static int link_elf_link_preload(linker_class_t cls, 140 const char *, linker_file_t *); 141 static int link_elf_link_preload_finish(linker_file_t); 142 static int link_elf_load_file(linker_class_t, const char *, 143 linker_file_t *); 144 static int link_elf_lookup_symbol(linker_file_t, const char *, 145 c_linker_sym_t *); 146 static int link_elf_symbol_values(linker_file_t, c_linker_sym_t, 147 linker_symval_t *); 148 static int link_elf_search_symbol(linker_file_t, caddr_t, 149 c_linker_sym_t *, long *); 150 151 static void link_elf_unload_file(linker_file_t); 152 static void link_elf_unload_preload(linker_file_t); 153 static int link_elf_lookup_set(linker_file_t, const char *, 154 void ***, void ***, int *); 155 static int link_elf_each_function_name(linker_file_t, 156 int (*)(const char *, void *), void *); 157 static int link_elf_each_function_nameval(linker_file_t, 158 linker_function_nameval_callback_t, void *); 159 static void link_elf_reloc_local(linker_file_t); 160 static long link_elf_symtab_get(linker_file_t, const Elf_Sym **); 161 static long link_elf_strtab_get(linker_file_t, caddr_t *); 162 static int elf_lookup(linker_file_t, Elf_Size, int, Elf_Addr *); 163 164 static kobj_method_t link_elf_methods[] = { 165 KOBJMETHOD(linker_lookup_symbol, link_elf_lookup_symbol), 166 KOBJMETHOD(linker_symbol_values, link_elf_symbol_values), 167 KOBJMETHOD(linker_search_symbol, link_elf_search_symbol), 168 KOBJMETHOD(linker_unload, link_elf_unload_file), 169 KOBJMETHOD(linker_load_file, link_elf_load_file), 170 KOBJMETHOD(linker_link_preload, link_elf_link_preload), 171 KOBJMETHOD(linker_link_preload_finish, link_elf_link_preload_finish), 172 KOBJMETHOD(linker_lookup_set, link_elf_lookup_set), 173 KOBJMETHOD(linker_each_function_name, link_elf_each_function_name), 174 KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval), 175 KOBJMETHOD(linker_ctf_get, link_elf_ctf_get), 176 KOBJMETHOD(linker_symtab_get, link_elf_symtab_get), 177 KOBJMETHOD(linker_strtab_get, link_elf_strtab_get), 178 KOBJMETHOD_END 179 }; 180 181 static struct linker_class link_elf_class = { 182 #if ELF_TARG_CLASS == ELFCLASS32 183 "elf32", 184 #else 185 "elf64", 186 #endif 187 link_elf_methods, sizeof(struct elf_file) 188 }; 189 190 typedef int (*elf_reloc_fn)(linker_file_t lf, Elf_Addr relocbase, 191 const void *data, int type, elf_lookup_fn lookup); 192 193 static int parse_dynamic(elf_file_t); 194 static int relocate_file(elf_file_t); 195 static int relocate_file1(elf_file_t ef, elf_lookup_fn lookup, 196 elf_reloc_fn reloc, bool ifuncs); 197 static int link_elf_preload_parse_symbols(elf_file_t); 198 199 static struct elf_set_head set_pcpu_list; 200 #ifdef VIMAGE 201 static struct elf_set_head set_vnet_list; 202 #endif 203 204 static void 205 elf_set_add(struct elf_set_head *list, Elf_Addr start, Elf_Addr stop, Elf_Addr base) 206 { 207 struct elf_set *set, *iter; 208 209 set = malloc(sizeof(*set), M_LINKER, M_WAITOK); 210 set->es_start = start; 211 set->es_stop = stop; 212 set->es_base = base; 213 214 TAILQ_FOREACH(iter, list, es_link) { 215 216 KASSERT((set->es_start < iter->es_start && set->es_stop < iter->es_stop) || 217 (set->es_start > iter->es_start && set->es_stop > iter->es_stop), 218 ("linker sets intersection: to insert: 0x%jx-0x%jx; inserted: 0x%jx-0x%jx", 219 (uintmax_t)set->es_start, (uintmax_t)set->es_stop, 220 (uintmax_t)iter->es_start, (uintmax_t)iter->es_stop)); 221 222 if (iter->es_start > set->es_start) { 223 TAILQ_INSERT_BEFORE(iter, set, es_link); 224 break; 225 } 226 } 227 228 if (iter == NULL) 229 TAILQ_INSERT_TAIL(list, set, es_link); 230 } 231 232 static int 233 elf_set_find(struct elf_set_head *list, Elf_Addr addr, Elf_Addr *start, Elf_Addr *base) 234 { 235 struct elf_set *set; 236 237 TAILQ_FOREACH(set, list, es_link) { 238 if (addr < set->es_start) 239 return (0); 240 if (addr < set->es_stop) { 241 *start = set->es_start; 242 *base = set->es_base; 243 return (1); 244 } 245 } 246 247 return (0); 248 } 249 250 static void 251 elf_set_delete(struct elf_set_head *list, Elf_Addr start) 252 { 253 struct elf_set *set; 254 255 TAILQ_FOREACH(set, list, es_link) { 256 if (start < set->es_start) 257 break; 258 if (start == set->es_start) { 259 TAILQ_REMOVE(list, set, es_link); 260 free(set, M_LINKER); 261 return; 262 } 263 } 264 KASSERT(0, ("deleting unknown linker set (start = 0x%jx)", 265 (uintmax_t)start)); 266 } 267 268 #ifdef GDB 269 static void r_debug_state(struct r_debug *, struct link_map *); 270 271 /* 272 * A list of loaded modules for GDB to use for loading symbols. 273 */ 274 struct r_debug r_debug; 275 276 #define GDB_STATE(s) do { \ 277 r_debug.r_state = s; r_debug_state(NULL, NULL); \ 278 } while (0) 279 280 /* 281 * Function for the debugger to set a breakpoint on to gain control. 282 */ 283 static void 284 r_debug_state(struct r_debug *dummy_one __unused, 285 struct link_map *dummy_two __unused) 286 { 287 } 288 289 static void 290 link_elf_add_gdb(struct link_map *l) 291 { 292 struct link_map *prev; 293 294 l->l_next = NULL; 295 296 if (r_debug.r_map == NULL) { 297 /* Add first. */ 298 l->l_prev = NULL; 299 r_debug.r_map = l; 300 } else { 301 /* Append to list. */ 302 for (prev = r_debug.r_map; 303 prev->l_next != NULL; 304 prev = prev->l_next) 305 ; 306 l->l_prev = prev; 307 prev->l_next = l; 308 } 309 } 310 311 static void 312 link_elf_delete_gdb(struct link_map *l) 313 { 314 if (l->l_prev == NULL) { 315 /* Remove first. */ 316 if ((r_debug.r_map = l->l_next) != NULL) 317 l->l_next->l_prev = NULL; 318 } else { 319 /* Remove any but first. */ 320 if ((l->l_prev->l_next = l->l_next) != NULL) 321 l->l_next->l_prev = l->l_prev; 322 } 323 } 324 #endif /* GDB */ 325 326 /* 327 * The kernel symbol table starts here. 328 */ 329 extern struct _dynamic _DYNAMIC; 330 331 static void 332 link_elf_error(const char *filename, const char *s) 333 { 334 if (filename == NULL) 335 printf("kldload: %s\n", s); 336 else 337 printf("kldload: %s: %s\n", filename, s); 338 } 339 340 static void 341 link_elf_invoke_ctors(caddr_t addr, size_t size) 342 { 343 void (**ctor)(void); 344 size_t i, cnt; 345 346 if (addr == NULL || size == 0) 347 return; 348 cnt = size / sizeof(*ctor); 349 ctor = (void *)addr; 350 for (i = 0; i < cnt; i++) { 351 if (ctor[i] != NULL) 352 (*ctor[i])(); 353 } 354 } 355 356 /* 357 * Actions performed after linking/loading both the preloaded kernel and any 358 * modules; whether preloaded or dynamicly loaded. 359 */ 360 static int 361 link_elf_link_common_finish(linker_file_t lf) 362 { 363 #ifdef GDB 364 elf_file_t ef = (elf_file_t)lf; 365 char *newfilename; 366 #endif 367 int error; 368 369 /* Notify MD code that a module is being loaded. */ 370 error = elf_cpu_load_file(lf); 371 if (error != 0) 372 return (error); 373 374 #ifdef GDB 375 GDB_STATE(RT_ADD); 376 ef->gdb.l_addr = lf->address; 377 newfilename = malloc(strlen(lf->filename) + 1, M_LINKER, M_WAITOK); 378 strcpy(newfilename, lf->filename); 379 ef->gdb.l_name = newfilename; 380 ef->gdb.l_ld = ef->dynamic; 381 link_elf_add_gdb(&ef->gdb); 382 GDB_STATE(RT_CONSISTENT); 383 #endif 384 385 /* Invoke .ctors */ 386 link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size); 387 return (0); 388 } 389 390 extern vm_offset_t __startkernel, __endkernel; 391 392 static void 393 link_elf_init(void* arg) 394 { 395 Elf_Dyn *dp; 396 Elf_Addr *ctors_addrp; 397 Elf_Size *ctors_sizep; 398 caddr_t modptr, baseptr, sizeptr; 399 elf_file_t ef; 400 char *modname; 401 402 linker_add_class(&link_elf_class); 403 404 dp = (Elf_Dyn *)&_DYNAMIC; 405 modname = NULL; 406 modptr = preload_search_by_type("elf" __XSTRING(__ELF_WORD_SIZE) " kernel"); 407 if (modptr == NULL) 408 modptr = preload_search_by_type("elf kernel"); 409 modname = (char *)preload_search_info(modptr, MODINFO_NAME); 410 if (modname == NULL) 411 modname = "kernel"; 412 linker_kernel_file = linker_make_file(modname, &link_elf_class); 413 if (linker_kernel_file == NULL) 414 panic("%s: Can't create linker structures for kernel", 415 __func__); 416 417 ef = (elf_file_t) linker_kernel_file; 418 ef->preloaded = 1; 419 #ifdef __powerpc__ 420 ef->address = (caddr_t) (__startkernel - KERNBASE); 421 #else 422 ef->address = 0; 423 #endif 424 #ifdef SPARSE_MAPPING 425 ef->object = NULL; 426 #endif 427 ef->dynamic = dp; 428 429 if (dp != NULL) 430 parse_dynamic(ef); 431 #ifdef __powerpc__ 432 linker_kernel_file->address = (caddr_t)__startkernel; 433 linker_kernel_file->size = (intptr_t)(__endkernel - __startkernel); 434 #else 435 linker_kernel_file->address += KERNBASE; 436 linker_kernel_file->size = -(intptr_t)linker_kernel_file->address; 437 #endif 438 439 if (modptr != NULL) { 440 ef->modptr = modptr; 441 baseptr = preload_search_info(modptr, MODINFO_ADDR); 442 if (baseptr != NULL) 443 linker_kernel_file->address = *(caddr_t *)baseptr; 444 sizeptr = preload_search_info(modptr, MODINFO_SIZE); 445 if (sizeptr != NULL) 446 linker_kernel_file->size = *(size_t *)sizeptr; 447 ctors_addrp = (Elf_Addr *)preload_search_info(modptr, 448 MODINFO_METADATA | MODINFOMD_CTORS_ADDR); 449 ctors_sizep = (Elf_Size *)preload_search_info(modptr, 450 MODINFO_METADATA | MODINFOMD_CTORS_SIZE); 451 if (ctors_addrp != NULL && ctors_sizep != NULL) { 452 linker_kernel_file->ctors_addr = ef->address + 453 *ctors_addrp; 454 linker_kernel_file->ctors_size = *ctors_sizep; 455 } 456 } 457 (void)link_elf_preload_parse_symbols(ef); 458 459 #ifdef GDB 460 r_debug.r_map = NULL; 461 r_debug.r_brk = r_debug_state; 462 r_debug.r_state = RT_CONSISTENT; 463 #endif 464 465 (void)link_elf_link_common_finish(linker_kernel_file); 466 linker_kernel_file->flags |= LINKER_FILE_LINKED; 467 TAILQ_INIT(&set_pcpu_list); 468 #ifdef VIMAGE 469 TAILQ_INIT(&set_vnet_list); 470 #endif 471 } 472 473 SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_THIRD, link_elf_init, NULL); 474 475 static int 476 link_elf_preload_parse_symbols(elf_file_t ef) 477 { 478 caddr_t pointer; 479 caddr_t ssym, esym, base; 480 caddr_t strtab; 481 int strcnt; 482 Elf_Sym *symtab; 483 int symcnt; 484 485 if (ef->modptr == NULL) 486 return (0); 487 pointer = preload_search_info(ef->modptr, 488 MODINFO_METADATA | MODINFOMD_SSYM); 489 if (pointer == NULL) 490 return (0); 491 ssym = *(caddr_t *)pointer; 492 pointer = preload_search_info(ef->modptr, 493 MODINFO_METADATA | MODINFOMD_ESYM); 494 if (pointer == NULL) 495 return (0); 496 esym = *(caddr_t *)pointer; 497 498 base = ssym; 499 500 symcnt = *(long *)base; 501 base += sizeof(long); 502 symtab = (Elf_Sym *)base; 503 base += roundup(symcnt, sizeof(long)); 504 505 if (base > esym || base < ssym) { 506 printf("Symbols are corrupt!\n"); 507 return (EINVAL); 508 } 509 510 strcnt = *(long *)base; 511 base += sizeof(long); 512 strtab = base; 513 base += roundup(strcnt, sizeof(long)); 514 515 if (base > esym || base < ssym) { 516 printf("Symbols are corrupt!\n"); 517 return (EINVAL); 518 } 519 520 ef->ddbsymtab = symtab; 521 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym); 522 ef->ddbstrtab = strtab; 523 ef->ddbstrcnt = strcnt; 524 525 return (0); 526 } 527 528 static int 529 parse_dynamic(elf_file_t ef) 530 { 531 Elf_Dyn *dp; 532 int plttype = DT_REL; 533 534 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) { 535 switch (dp->d_tag) { 536 case DT_HASH: 537 { 538 /* From src/libexec/rtld-elf/rtld.c */ 539 const Elf_Hashelt *hashtab = (const Elf_Hashelt *) 540 (ef->address + dp->d_un.d_ptr); 541 ef->nbuckets = hashtab[0]; 542 ef->nchains = hashtab[1]; 543 ef->buckets = hashtab + 2; 544 ef->chains = ef->buckets + ef->nbuckets; 545 break; 546 } 547 case DT_STRTAB: 548 ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr); 549 break; 550 case DT_STRSZ: 551 ef->strsz = dp->d_un.d_val; 552 break; 553 case DT_SYMTAB: 554 ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr); 555 break; 556 case DT_SYMENT: 557 if (dp->d_un.d_val != sizeof(Elf_Sym)) 558 return (ENOEXEC); 559 break; 560 case DT_PLTGOT: 561 ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr); 562 break; 563 case DT_REL: 564 ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr); 565 break; 566 case DT_RELSZ: 567 ef->relsize = dp->d_un.d_val; 568 break; 569 case DT_RELENT: 570 if (dp->d_un.d_val != sizeof(Elf_Rel)) 571 return (ENOEXEC); 572 break; 573 case DT_JMPREL: 574 ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr); 575 break; 576 case DT_PLTRELSZ: 577 ef->pltrelsize = dp->d_un.d_val; 578 break; 579 case DT_RELA: 580 ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr); 581 break; 582 case DT_RELASZ: 583 ef->relasize = dp->d_un.d_val; 584 break; 585 case DT_RELAENT: 586 if (dp->d_un.d_val != sizeof(Elf_Rela)) 587 return (ENOEXEC); 588 break; 589 case DT_PLTREL: 590 plttype = dp->d_un.d_val; 591 if (plttype != DT_REL && plttype != DT_RELA) 592 return (ENOEXEC); 593 break; 594 #ifdef GDB 595 case DT_DEBUG: 596 dp->d_un.d_ptr = (Elf_Addr)&r_debug; 597 break; 598 #endif 599 } 600 } 601 602 if (plttype == DT_RELA) { 603 ef->pltrela = (const Elf_Rela *)ef->pltrel; 604 ef->pltrel = NULL; 605 ef->pltrelasize = ef->pltrelsize; 606 ef->pltrelsize = 0; 607 } 608 609 ef->ddbsymtab = ef->symtab; 610 ef->ddbsymcnt = ef->nchains; 611 ef->ddbstrtab = ef->strtab; 612 ef->ddbstrcnt = ef->strsz; 613 614 return (0); 615 } 616 617 static int 618 parse_dpcpu(elf_file_t ef) 619 { 620 int error, size; 621 622 ef->pcpu_start = 0; 623 ef->pcpu_stop = 0; 624 error = link_elf_lookup_set(&ef->lf, "pcpu", (void ***)&ef->pcpu_start, 625 (void ***)&ef->pcpu_stop, NULL); 626 /* Error just means there is no pcpu set to relocate. */ 627 if (error != 0) 628 return (0); 629 size = (uintptr_t)ef->pcpu_stop - (uintptr_t)ef->pcpu_start; 630 /* Empty set? */ 631 if (size < 1) 632 return (0); 633 /* 634 * Allocate space in the primary pcpu area. Copy in our 635 * initialization from the data section and then initialize 636 * all per-cpu storage from that. 637 */ 638 ef->pcpu_base = (Elf_Addr)(uintptr_t)dpcpu_alloc(size); 639 if (ef->pcpu_base == 0) { 640 printf("%s: pcpu module space is out of space; " 641 "cannot allocate %d for %s\n", 642 __func__, size, ef->lf.pathname); 643 return (ENOSPC); 644 } 645 memcpy((void *)ef->pcpu_base, (void *)ef->pcpu_start, size); 646 dpcpu_copy((void *)ef->pcpu_base, size); 647 elf_set_add(&set_pcpu_list, ef->pcpu_start, ef->pcpu_stop, 648 ef->pcpu_base); 649 650 return (0); 651 } 652 653 #ifdef VIMAGE 654 static int 655 parse_vnet(elf_file_t ef) 656 { 657 int error, size; 658 659 ef->vnet_start = 0; 660 ef->vnet_stop = 0; 661 error = link_elf_lookup_set(&ef->lf, "vnet", (void ***)&ef->vnet_start, 662 (void ***)&ef->vnet_stop, NULL); 663 /* Error just means there is no vnet data set to relocate. */ 664 if (error != 0) 665 return (0); 666 size = (uintptr_t)ef->vnet_stop - (uintptr_t)ef->vnet_start; 667 /* Empty set? */ 668 if (size < 1) 669 return (0); 670 /* 671 * Allocate space in the primary vnet area. Copy in our 672 * initialization from the data section and then initialize 673 * all per-vnet storage from that. 674 */ 675 ef->vnet_base = (Elf_Addr)(uintptr_t)vnet_data_alloc(size); 676 if (ef->vnet_base == 0) { 677 printf("%s: vnet module space is out of space; " 678 "cannot allocate %d for %s\n", 679 __func__, size, ef->lf.pathname); 680 return (ENOSPC); 681 } 682 memcpy((void *)ef->vnet_base, (void *)ef->vnet_start, size); 683 vnet_data_copy((void *)ef->vnet_base, size); 684 elf_set_add(&set_vnet_list, ef->vnet_start, ef->vnet_stop, 685 ef->vnet_base); 686 687 return (0); 688 } 689 #endif 690 691 #ifdef __arm__ 692 /* 693 * Locate the ARM exception/unwind table info for DDB and stack(9) use by 694 * searching for the section header that describes it. There may be no unwind 695 * info, for example in a module containing only data. 696 */ 697 static void 698 link_elf_locate_exidx(linker_file_t lf, Elf_Shdr *shdr, int nhdr) 699 { 700 int i; 701 702 for (i = 0; i < nhdr; i++) { 703 if (shdr[i].sh_type == SHT_ARM_EXIDX) { 704 lf->exidx_addr = shdr[i].sh_addr + lf->address; 705 lf->exidx_size = shdr[i].sh_size; 706 break; 707 } 708 } 709 } 710 711 /* 712 * Locate the section headers metadata in a preloaded module, then use it to 713 * locate the exception/unwind table in the module. The size of the metadata 714 * block is stored in a uint32 word immediately before the data itself, and a 715 * comment in preload_search_info() says it is safe to rely on that. 716 */ 717 static void 718 link_elf_locate_exidx_preload(struct linker_file *lf, caddr_t modptr) 719 { 720 uint32_t *modinfo; 721 Elf_Shdr *shdr; 722 uint32_t nhdr; 723 724 modinfo = (uint32_t *)preload_search_info(modptr, 725 MODINFO_METADATA | MODINFOMD_SHDR); 726 if (modinfo != NULL) { 727 shdr = (Elf_Shdr *)modinfo; 728 nhdr = modinfo[-1] / sizeof(Elf_Shdr); 729 link_elf_locate_exidx(lf, shdr, nhdr); 730 } 731 } 732 733 #endif /* __arm__ */ 734 735 static int 736 link_elf_link_preload(linker_class_t cls, 737 const char* filename, linker_file_t *result) 738 { 739 Elf_Addr *ctors_addrp; 740 Elf_Size *ctors_sizep; 741 caddr_t modptr, baseptr, sizeptr, dynptr; 742 char *type; 743 elf_file_t ef; 744 linker_file_t lf; 745 int error; 746 vm_offset_t dp; 747 748 /* Look to see if we have the file preloaded */ 749 modptr = preload_search_by_name(filename); 750 if (modptr == NULL) 751 return (ENOENT); 752 753 type = (char *)preload_search_info(modptr, MODINFO_TYPE); 754 baseptr = preload_search_info(modptr, MODINFO_ADDR); 755 sizeptr = preload_search_info(modptr, MODINFO_SIZE); 756 dynptr = preload_search_info(modptr, 757 MODINFO_METADATA | MODINFOMD_DYNAMIC); 758 if (type == NULL || 759 (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) " module") != 0 && 760 strcmp(type, "elf module") != 0)) 761 return (EFTYPE); 762 if (baseptr == NULL || sizeptr == NULL || dynptr == NULL) 763 return (EINVAL); 764 765 lf = linker_make_file(filename, &link_elf_class); 766 if (lf == NULL) 767 return (ENOMEM); 768 769 ef = (elf_file_t) lf; 770 ef->preloaded = 1; 771 ef->modptr = modptr; 772 ef->address = *(caddr_t *)baseptr; 773 #ifdef SPARSE_MAPPING 774 ef->object = NULL; 775 #endif 776 dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr; 777 ef->dynamic = (Elf_Dyn *)dp; 778 lf->address = ef->address; 779 lf->size = *(size_t *)sizeptr; 780 781 ctors_addrp = (Elf_Addr *)preload_search_info(modptr, 782 MODINFO_METADATA | MODINFOMD_CTORS_ADDR); 783 ctors_sizep = (Elf_Size *)preload_search_info(modptr, 784 MODINFO_METADATA | MODINFOMD_CTORS_SIZE); 785 if (ctors_addrp != NULL && ctors_sizep != NULL) { 786 lf->ctors_addr = ef->address + *ctors_addrp; 787 lf->ctors_size = *ctors_sizep; 788 } 789 790 #ifdef __arm__ 791 link_elf_locate_exidx_preload(lf, modptr); 792 #endif 793 794 error = parse_dynamic(ef); 795 if (error == 0) 796 error = parse_dpcpu(ef); 797 #ifdef VIMAGE 798 if (error == 0) 799 error = parse_vnet(ef); 800 #endif 801 if (error != 0) { 802 linker_file_unload(lf, LINKER_UNLOAD_FORCE); 803 return (error); 804 } 805 link_elf_reloc_local(lf); 806 *result = lf; 807 return (0); 808 } 809 810 static int 811 link_elf_link_preload_finish(linker_file_t lf) 812 { 813 elf_file_t ef; 814 int error; 815 816 ef = (elf_file_t) lf; 817 error = relocate_file(ef); 818 if (error != 0) 819 return (error); 820 (void)link_elf_preload_parse_symbols(ef); 821 822 return (link_elf_link_common_finish(lf)); 823 } 824 825 static int 826 link_elf_load_file(linker_class_t cls, const char* filename, 827 linker_file_t* result) 828 { 829 struct nameidata nd; 830 struct thread* td = curthread; /* XXX */ 831 Elf_Ehdr *hdr; 832 caddr_t firstpage, segbase; 833 int nbytes, i; 834 Elf_Phdr *phdr; 835 Elf_Phdr *phlimit; 836 Elf_Phdr *segs[MAXSEGS]; 837 int nsegs; 838 Elf_Phdr *phdyn; 839 caddr_t mapbase; 840 size_t mapsize; 841 Elf_Addr base_vaddr; 842 Elf_Addr base_vlimit; 843 int error = 0; 844 ssize_t resid; 845 int flags; 846 elf_file_t ef; 847 linker_file_t lf; 848 Elf_Shdr *shdr; 849 int symtabindex; 850 int symstrindex; 851 int shstrindex; 852 int symcnt; 853 int strcnt; 854 char *shstrs; 855 856 shdr = NULL; 857 lf = NULL; 858 shstrs = NULL; 859 860 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td); 861 flags = FREAD; 862 error = vn_open(&nd, &flags, 0, NULL); 863 if (error != 0) 864 return (error); 865 NDFREE(&nd, NDF_ONLY_PNBUF); 866 if (nd.ni_vp->v_type != VREG) { 867 error = ENOEXEC; 868 firstpage = NULL; 869 goto out; 870 } 871 #ifdef MAC 872 error = mac_kld_check_load(curthread->td_ucred, nd.ni_vp); 873 if (error != 0) { 874 firstpage = NULL; 875 goto out; 876 } 877 #endif 878 879 /* 880 * Read the elf header from the file. 881 */ 882 firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK); 883 hdr = (Elf_Ehdr *)firstpage; 884 error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0, 885 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 886 &resid, td); 887 nbytes = PAGE_SIZE - resid; 888 if (error != 0) 889 goto out; 890 891 if (!IS_ELF(*hdr)) { 892 error = ENOEXEC; 893 goto out; 894 } 895 896 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS || 897 hdr->e_ident[EI_DATA] != ELF_TARG_DATA) { 898 link_elf_error(filename, "Unsupported file layout"); 899 error = ENOEXEC; 900 goto out; 901 } 902 if (hdr->e_ident[EI_VERSION] != EV_CURRENT || 903 hdr->e_version != EV_CURRENT) { 904 link_elf_error(filename, "Unsupported file version"); 905 error = ENOEXEC; 906 goto out; 907 } 908 if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) { 909 error = ENOSYS; 910 goto out; 911 } 912 if (hdr->e_machine != ELF_TARG_MACH) { 913 link_elf_error(filename, "Unsupported machine"); 914 error = ENOEXEC; 915 goto out; 916 } 917 918 /* 919 * We rely on the program header being in the first page. 920 * This is not strictly required by the ABI specification, but 921 * it seems to always true in practice. And, it simplifies 922 * things considerably. 923 */ 924 if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) && 925 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) && 926 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes))) 927 link_elf_error(filename, "Unreadable program headers"); 928 929 /* 930 * Scan the program header entries, and save key information. 931 * 932 * We rely on there being exactly two load segments, text and data, 933 * in that order. 934 */ 935 phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff); 936 phlimit = phdr + hdr->e_phnum; 937 nsegs = 0; 938 phdyn = NULL; 939 while (phdr < phlimit) { 940 switch (phdr->p_type) { 941 case PT_LOAD: 942 if (nsegs == MAXSEGS) { 943 link_elf_error(filename, "Too many sections"); 944 error = ENOEXEC; 945 goto out; 946 } 947 /* 948 * XXX: We just trust they come in right order ?? 949 */ 950 segs[nsegs] = phdr; 951 ++nsegs; 952 break; 953 954 case PT_DYNAMIC: 955 phdyn = phdr; 956 break; 957 958 case PT_INTERP: 959 error = ENOSYS; 960 goto out; 961 } 962 963 ++phdr; 964 } 965 if (phdyn == NULL) { 966 link_elf_error(filename, "Object is not dynamically-linked"); 967 error = ENOEXEC; 968 goto out; 969 } 970 if (nsegs == 0) { 971 link_elf_error(filename, "No sections"); 972 error = ENOEXEC; 973 goto out; 974 } 975 976 /* 977 * Allocate the entire address space of the object, to stake 978 * out our contiguous region, and to establish the base 979 * address for relocation. 980 */ 981 base_vaddr = trunc_page(segs[0]->p_vaddr); 982 base_vlimit = round_page(segs[nsegs - 1]->p_vaddr + 983 segs[nsegs - 1]->p_memsz); 984 mapsize = base_vlimit - base_vaddr; 985 986 lf = linker_make_file(filename, &link_elf_class); 987 if (lf == NULL) { 988 error = ENOMEM; 989 goto out; 990 } 991 992 ef = (elf_file_t) lf; 993 #ifdef SPARSE_MAPPING 994 ef->object = vm_pager_allocate(OBJT_PHYS, NULL, mapsize, VM_PROT_ALL, 995 0, thread0.td_ucred); 996 if (ef->object == NULL) { 997 error = ENOMEM; 998 goto out; 999 } 1000 #ifdef __amd64__ 1001 mapbase = (caddr_t)KERNBASE; 1002 #else 1003 mapbase = (caddr_t)vm_map_min(kernel_map); 1004 #endif 1005 /* 1006 * Mapping protections are downgraded after relocation processing. 1007 */ 1008 error = vm_map_find(kernel_map, ef->object, 0, 1009 (vm_offset_t *)&mapbase, mapsize, 0, VMFS_OPTIMAL_SPACE, 1010 VM_PROT_ALL, VM_PROT_ALL, 0); 1011 if (error != 0) { 1012 vm_object_deallocate(ef->object); 1013 ef->object = NULL; 1014 goto out; 1015 } 1016 #else 1017 mapbase = malloc(mapsize, M_LINKER, M_EXEC | M_WAITOK); 1018 #endif 1019 ef->address = mapbase; 1020 1021 /* 1022 * Read the text and data sections and zero the bss. 1023 */ 1024 for (i = 0; i < nsegs; i++) { 1025 segbase = mapbase + segs[i]->p_vaddr - base_vaddr; 1026 1027 #ifdef SPARSE_MAPPING 1028 /* 1029 * Consecutive segments may have different mapping permissions, 1030 * so be strict and verify that their mappings do not overlap. 1031 */ 1032 if (((vm_offset_t)segbase & PAGE_MASK) != 0) { 1033 error = EINVAL; 1034 goto out; 1035 } 1036 1037 error = vm_map_wire(kernel_map, 1038 (vm_offset_t)segbase, 1039 (vm_offset_t)segbase + round_page(segs[i]->p_memsz), 1040 VM_MAP_WIRE_SYSTEM | VM_MAP_WIRE_NOHOLES); 1041 if (error != KERN_SUCCESS) { 1042 error = ENOMEM; 1043 goto out; 1044 } 1045 #endif 1046 1047 error = vn_rdwr(UIO_READ, nd.ni_vp, 1048 segbase, segs[i]->p_filesz, segs[i]->p_offset, 1049 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1050 &resid, td); 1051 if (error != 0) 1052 goto out; 1053 bzero(segbase + segs[i]->p_filesz, 1054 segs[i]->p_memsz - segs[i]->p_filesz); 1055 } 1056 1057 #ifdef GPROF 1058 /* Update profiling information with the new text segment. */ 1059 mtx_lock(&Giant); 1060 kmupetext((uintfptr_t)(mapbase + segs[0]->p_vaddr - base_vaddr + 1061 segs[0]->p_memsz)); 1062 mtx_unlock(&Giant); 1063 #endif 1064 1065 ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr); 1066 1067 lf->address = ef->address; 1068 lf->size = mapsize; 1069 1070 error = parse_dynamic(ef); 1071 if (error != 0) 1072 goto out; 1073 error = parse_dpcpu(ef); 1074 if (error != 0) 1075 goto out; 1076 #ifdef VIMAGE 1077 error = parse_vnet(ef); 1078 if (error != 0) 1079 goto out; 1080 #endif 1081 link_elf_reloc_local(lf); 1082 1083 VOP_UNLOCK(nd.ni_vp, 0); 1084 error = linker_load_dependencies(lf); 1085 vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY); 1086 if (error != 0) 1087 goto out; 1088 error = relocate_file(ef); 1089 if (error != 0) 1090 goto out; 1091 1092 #ifdef SPARSE_MAPPING 1093 /* 1094 * Downgrade permissions on text segment mappings now that relocation 1095 * processing is complete. Restrict permissions on read-only segments. 1096 */ 1097 for (i = 0; i < nsegs; i++) { 1098 vm_prot_t prot; 1099 1100 if (segs[i]->p_type != PT_LOAD) 1101 continue; 1102 1103 prot = VM_PROT_READ; 1104 if ((segs[i]->p_flags & PF_W) != 0) 1105 prot |= VM_PROT_WRITE; 1106 if ((segs[i]->p_flags & PF_X) != 0) 1107 prot |= VM_PROT_EXECUTE; 1108 segbase = mapbase + segs[i]->p_vaddr - base_vaddr; 1109 error = vm_map_protect(kernel_map, 1110 (vm_offset_t)segbase, 1111 (vm_offset_t)segbase + round_page(segs[i]->p_memsz), 1112 prot, FALSE); 1113 if (error != KERN_SUCCESS) { 1114 error = ENOMEM; 1115 goto out; 1116 } 1117 } 1118 #endif 1119 1120 /* 1121 * Try and load the symbol table if it's present. (you can 1122 * strip it!) 1123 */ 1124 nbytes = hdr->e_shnum * hdr->e_shentsize; 1125 if (nbytes == 0 || hdr->e_shoff == 0) 1126 goto nosyms; 1127 shdr = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO); 1128 error = vn_rdwr(UIO_READ, nd.ni_vp, 1129 (caddr_t)shdr, nbytes, hdr->e_shoff, 1130 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1131 &resid, td); 1132 if (error != 0) 1133 goto out; 1134 1135 /* Read section string table */ 1136 shstrindex = hdr->e_shstrndx; 1137 if (shstrindex != 0 && shdr[shstrindex].sh_type == SHT_STRTAB && 1138 shdr[shstrindex].sh_size != 0) { 1139 nbytes = shdr[shstrindex].sh_size; 1140 shstrs = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO); 1141 error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)shstrs, nbytes, 1142 shdr[shstrindex].sh_offset, UIO_SYSSPACE, IO_NODELOCKED, 1143 td->td_ucred, NOCRED, &resid, td); 1144 if (error) 1145 goto out; 1146 } 1147 1148 symtabindex = -1; 1149 symstrindex = -1; 1150 for (i = 0; i < hdr->e_shnum; i++) { 1151 if (shdr[i].sh_type == SHT_SYMTAB) { 1152 symtabindex = i; 1153 symstrindex = shdr[i].sh_link; 1154 } else if (shstrs != NULL && shdr[i].sh_name != 0 && 1155 strcmp(shstrs + shdr[i].sh_name, ".ctors") == 0) { 1156 /* Record relocated address and size of .ctors. */ 1157 lf->ctors_addr = mapbase + shdr[i].sh_addr - base_vaddr; 1158 lf->ctors_size = shdr[i].sh_size; 1159 } 1160 } 1161 if (symtabindex < 0 || symstrindex < 0) 1162 goto nosyms; 1163 1164 symcnt = shdr[symtabindex].sh_size; 1165 ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK); 1166 strcnt = shdr[symstrindex].sh_size; 1167 ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK); 1168 1169 error = vn_rdwr(UIO_READ, nd.ni_vp, 1170 ef->symbase, symcnt, shdr[symtabindex].sh_offset, 1171 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1172 &resid, td); 1173 if (error != 0) 1174 goto out; 1175 error = vn_rdwr(UIO_READ, nd.ni_vp, 1176 ef->strbase, strcnt, shdr[symstrindex].sh_offset, 1177 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1178 &resid, td); 1179 if (error != 0) 1180 goto out; 1181 1182 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym); 1183 ef->ddbsymtab = (const Elf_Sym *)ef->symbase; 1184 ef->ddbstrcnt = strcnt; 1185 ef->ddbstrtab = ef->strbase; 1186 1187 nosyms: 1188 1189 #ifdef __arm__ 1190 link_elf_locate_exidx(lf, shdr, hdr->e_shnum); 1191 #endif 1192 1193 error = link_elf_link_common_finish(lf); 1194 if (error != 0) 1195 goto out; 1196 1197 *result = lf; 1198 1199 out: 1200 VOP_UNLOCK(nd.ni_vp, 0); 1201 vn_close(nd.ni_vp, FREAD, td->td_ucred, td); 1202 if (error != 0 && lf != NULL) 1203 linker_file_unload(lf, LINKER_UNLOAD_FORCE); 1204 free(shdr, M_LINKER); 1205 free(firstpage, M_LINKER); 1206 free(shstrs, M_LINKER); 1207 1208 return (error); 1209 } 1210 1211 Elf_Addr 1212 elf_relocaddr(linker_file_t lf, Elf_Addr x) 1213 { 1214 elf_file_t ef; 1215 1216 KASSERT(lf->ops->cls == (kobj_class_t)&link_elf_class, 1217 ("elf_relocaddr: unexpected linker file %p", lf)); 1218 1219 ef = (elf_file_t)lf; 1220 if (x >= ef->pcpu_start && x < ef->pcpu_stop) 1221 return ((x - ef->pcpu_start) + ef->pcpu_base); 1222 #ifdef VIMAGE 1223 if (x >= ef->vnet_start && x < ef->vnet_stop) 1224 return ((x - ef->vnet_start) + ef->vnet_base); 1225 #endif 1226 return (x); 1227 } 1228 1229 1230 static void 1231 link_elf_unload_file(linker_file_t file) 1232 { 1233 elf_file_t ef = (elf_file_t) file; 1234 1235 if (ef->pcpu_base != 0) { 1236 dpcpu_free((void *)ef->pcpu_base, 1237 ef->pcpu_stop - ef->pcpu_start); 1238 elf_set_delete(&set_pcpu_list, ef->pcpu_start); 1239 } 1240 #ifdef VIMAGE 1241 if (ef->vnet_base != 0) { 1242 vnet_data_free((void *)ef->vnet_base, 1243 ef->vnet_stop - ef->vnet_start); 1244 elf_set_delete(&set_vnet_list, ef->vnet_start); 1245 } 1246 #endif 1247 #ifdef GDB 1248 if (ef->gdb.l_ld != NULL) { 1249 GDB_STATE(RT_DELETE); 1250 free((void *)(uintptr_t)ef->gdb.l_name, M_LINKER); 1251 link_elf_delete_gdb(&ef->gdb); 1252 GDB_STATE(RT_CONSISTENT); 1253 } 1254 #endif 1255 1256 /* Notify MD code that a module is being unloaded. */ 1257 elf_cpu_unload_file(file); 1258 1259 if (ef->preloaded) { 1260 link_elf_unload_preload(file); 1261 return; 1262 } 1263 1264 #ifdef SPARSE_MAPPING 1265 if (ef->object != NULL) { 1266 vm_map_remove(kernel_map, (vm_offset_t) ef->address, 1267 (vm_offset_t) ef->address 1268 + (ef->object->size << PAGE_SHIFT)); 1269 } 1270 #else 1271 free(ef->address, M_LINKER); 1272 #endif 1273 free(ef->symbase, M_LINKER); 1274 free(ef->strbase, M_LINKER); 1275 free(ef->ctftab, M_LINKER); 1276 free(ef->ctfoff, M_LINKER); 1277 free(ef->typoff, M_LINKER); 1278 } 1279 1280 static void 1281 link_elf_unload_preload(linker_file_t file) 1282 { 1283 if (file->pathname != NULL) 1284 preload_delete_name(file->pathname); 1285 } 1286 1287 static const char * 1288 symbol_name(elf_file_t ef, Elf_Size r_info) 1289 { 1290 const Elf_Sym *ref; 1291 1292 if (ELF_R_SYM(r_info)) { 1293 ref = ef->symtab + ELF_R_SYM(r_info); 1294 return (ef->strtab + ref->st_name); 1295 } 1296 return (NULL); 1297 } 1298 1299 static int 1300 symbol_type(elf_file_t ef, Elf_Size r_info) 1301 { 1302 const Elf_Sym *ref; 1303 1304 if (ELF_R_SYM(r_info)) { 1305 ref = ef->symtab + ELF_R_SYM(r_info); 1306 return (ELF_ST_TYPE(ref->st_info)); 1307 } 1308 return (STT_NOTYPE); 1309 } 1310 1311 static int 1312 relocate_file1(elf_file_t ef, elf_lookup_fn lookup, elf_reloc_fn reloc, 1313 bool ifuncs) 1314 { 1315 const Elf_Rel *rel; 1316 const Elf_Rela *rela; 1317 const char *symname; 1318 1319 #define APPLY_RELOCS(iter, tbl, tblsize, type) do { \ 1320 for ((iter) = (tbl); (iter) != NULL && \ 1321 (iter) < (tbl) + (tblsize) / sizeof(*(iter)); (iter)++) { \ 1322 if ((symbol_type(ef, (iter)->r_info) == \ 1323 STT_GNU_IFUNC || \ 1324 elf_is_ifunc_reloc((iter)->r_info)) != ifuncs) \ 1325 continue; \ 1326 if (reloc(&ef->lf, (Elf_Addr)ef->address, \ 1327 (iter), (type), lookup)) { \ 1328 symname = symbol_name(ef, (iter)->r_info); \ 1329 printf("link_elf: symbol %s undefined\n", \ 1330 symname); \ 1331 return (ENOENT); \ 1332 } \ 1333 } \ 1334 } while (0) 1335 1336 APPLY_RELOCS(rel, ef->rel, ef->relsize, ELF_RELOC_REL); 1337 APPLY_RELOCS(rela, ef->rela, ef->relasize, ELF_RELOC_RELA); 1338 APPLY_RELOCS(rel, ef->pltrel, ef->pltrelsize, ELF_RELOC_REL); 1339 APPLY_RELOCS(rela, ef->pltrela, ef->pltrelasize, ELF_RELOC_RELA); 1340 1341 #undef APPLY_RELOCS 1342 1343 return (0); 1344 } 1345 1346 static int 1347 relocate_file(elf_file_t ef) 1348 { 1349 int error; 1350 1351 error = relocate_file1(ef, elf_lookup, elf_reloc, false); 1352 if (error == 0) 1353 error = relocate_file1(ef, elf_lookup, elf_reloc, true); 1354 return (error); 1355 } 1356 1357 /* 1358 * Hash function for symbol table lookup. Don't even think about changing 1359 * this. It is specified by the System V ABI. 1360 */ 1361 static unsigned long 1362 elf_hash(const char *name) 1363 { 1364 const unsigned char *p = (const unsigned char *) name; 1365 unsigned long h = 0; 1366 unsigned long g; 1367 1368 while (*p != '\0') { 1369 h = (h << 4) + *p++; 1370 if ((g = h & 0xf0000000) != 0) 1371 h ^= g >> 24; 1372 h &= ~g; 1373 } 1374 return (h); 1375 } 1376 1377 static int 1378 link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym) 1379 { 1380 elf_file_t ef = (elf_file_t) lf; 1381 unsigned long symnum; 1382 const Elf_Sym* symp; 1383 const char *strp; 1384 unsigned long hash; 1385 int i; 1386 1387 /* If we don't have a hash, bail. */ 1388 if (ef->buckets == NULL || ef->nbuckets == 0) { 1389 printf("link_elf_lookup_symbol: missing symbol hash table\n"); 1390 return (ENOENT); 1391 } 1392 1393 /* First, search hashed global symbols */ 1394 hash = elf_hash(name); 1395 symnum = ef->buckets[hash % ef->nbuckets]; 1396 1397 while (symnum != STN_UNDEF) { 1398 if (symnum >= ef->nchains) { 1399 printf("%s: corrupt symbol table\n", __func__); 1400 return (ENOENT); 1401 } 1402 1403 symp = ef->symtab + symnum; 1404 if (symp->st_name == 0) { 1405 printf("%s: corrupt symbol table\n", __func__); 1406 return (ENOENT); 1407 } 1408 1409 strp = ef->strtab + symp->st_name; 1410 1411 if (strcmp(name, strp) == 0) { 1412 if (symp->st_shndx != SHN_UNDEF || 1413 (symp->st_value != 0 && 1414 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1415 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC))) { 1416 *sym = (c_linker_sym_t) symp; 1417 return (0); 1418 } 1419 return (ENOENT); 1420 } 1421 1422 symnum = ef->chains[symnum]; 1423 } 1424 1425 /* If we have not found it, look at the full table (if loaded) */ 1426 if (ef->symtab == ef->ddbsymtab) 1427 return (ENOENT); 1428 1429 /* Exhaustive search */ 1430 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1431 strp = ef->ddbstrtab + symp->st_name; 1432 if (strcmp(name, strp) == 0) { 1433 if (symp->st_shndx != SHN_UNDEF || 1434 (symp->st_value != 0 && 1435 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1436 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC))) { 1437 *sym = (c_linker_sym_t) symp; 1438 return (0); 1439 } 1440 return (ENOENT); 1441 } 1442 } 1443 1444 return (ENOENT); 1445 } 1446 1447 static int 1448 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, 1449 linker_symval_t *symval) 1450 { 1451 elf_file_t ef; 1452 const Elf_Sym *es; 1453 caddr_t val; 1454 1455 ef = (elf_file_t)lf; 1456 es = (const Elf_Sym *)sym; 1457 if (es >= ef->symtab && es < (ef->symtab + ef->nchains)) { 1458 symval->name = ef->strtab + es->st_name; 1459 val = (caddr_t)ef->address + es->st_value; 1460 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC) 1461 val = ((caddr_t (*)(void))val)(); 1462 symval->value = val; 1463 symval->size = es->st_size; 1464 return (0); 1465 } 1466 if (ef->symtab == ef->ddbsymtab) 1467 return (ENOENT); 1468 if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) { 1469 symval->name = ef->ddbstrtab + es->st_name; 1470 val = (caddr_t)ef->address + es->st_value; 1471 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC) 1472 val = ((caddr_t (*)(void))val)(); 1473 symval->value = val; 1474 symval->size = es->st_size; 1475 return (0); 1476 } 1477 return (ENOENT); 1478 } 1479 1480 static int 1481 link_elf_search_symbol(linker_file_t lf, caddr_t value, 1482 c_linker_sym_t *sym, long *diffp) 1483 { 1484 elf_file_t ef = (elf_file_t) lf; 1485 u_long off = (uintptr_t) (void *) value; 1486 u_long diff = off; 1487 u_long st_value; 1488 const Elf_Sym* es; 1489 const Elf_Sym* best = NULL; 1490 int i; 1491 1492 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) { 1493 if (es->st_name == 0) 1494 continue; 1495 st_value = es->st_value + (uintptr_t) (void *) ef->address; 1496 if (off >= st_value) { 1497 if (off - st_value < diff) { 1498 diff = off - st_value; 1499 best = es; 1500 if (diff == 0) 1501 break; 1502 } else if (off - st_value == diff) { 1503 best = es; 1504 } 1505 } 1506 } 1507 if (best == NULL) 1508 *diffp = off; 1509 else 1510 *diffp = diff; 1511 *sym = (c_linker_sym_t) best; 1512 1513 return (0); 1514 } 1515 1516 /* 1517 * Look up a linker set on an ELF system. 1518 */ 1519 static int 1520 link_elf_lookup_set(linker_file_t lf, const char *name, 1521 void ***startp, void ***stopp, int *countp) 1522 { 1523 c_linker_sym_t sym; 1524 linker_symval_t symval; 1525 char *setsym; 1526 void **start, **stop; 1527 int len, error = 0, count; 1528 1529 len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */ 1530 setsym = malloc(len, M_LINKER, M_WAITOK); 1531 1532 /* get address of first entry */ 1533 snprintf(setsym, len, "%s%s", "__start_set_", name); 1534 error = link_elf_lookup_symbol(lf, setsym, &sym); 1535 if (error != 0) 1536 goto out; 1537 link_elf_symbol_values(lf, sym, &symval); 1538 if (symval.value == 0) { 1539 error = ESRCH; 1540 goto out; 1541 } 1542 start = (void **)symval.value; 1543 1544 /* get address of last entry */ 1545 snprintf(setsym, len, "%s%s", "__stop_set_", name); 1546 error = link_elf_lookup_symbol(lf, setsym, &sym); 1547 if (error != 0) 1548 goto out; 1549 link_elf_symbol_values(lf, sym, &symval); 1550 if (symval.value == 0) { 1551 error = ESRCH; 1552 goto out; 1553 } 1554 stop = (void **)symval.value; 1555 1556 /* and the number of entries */ 1557 count = stop - start; 1558 1559 /* and copy out */ 1560 if (startp != NULL) 1561 *startp = start; 1562 if (stopp != NULL) 1563 *stopp = stop; 1564 if (countp != NULL) 1565 *countp = count; 1566 1567 out: 1568 free(setsym, M_LINKER); 1569 return (error); 1570 } 1571 1572 static int 1573 link_elf_each_function_name(linker_file_t file, 1574 int (*callback)(const char *, void *), void *opaque) 1575 { 1576 elf_file_t ef = (elf_file_t)file; 1577 const Elf_Sym *symp; 1578 int i, error; 1579 1580 /* Exhaustive search */ 1581 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1582 if (symp->st_value != 0 && 1583 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1584 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) { 1585 error = callback(ef->ddbstrtab + symp->st_name, opaque); 1586 if (error != 0) 1587 return (error); 1588 } 1589 } 1590 return (0); 1591 } 1592 1593 static int 1594 link_elf_each_function_nameval(linker_file_t file, 1595 linker_function_nameval_callback_t callback, void *opaque) 1596 { 1597 linker_symval_t symval; 1598 elf_file_t ef = (elf_file_t)file; 1599 const Elf_Sym* symp; 1600 int i, error; 1601 1602 /* Exhaustive search */ 1603 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1604 if (symp->st_value != 0 && 1605 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1606 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) { 1607 error = link_elf_symbol_values(file, 1608 (c_linker_sym_t) symp, &symval); 1609 if (error != 0) 1610 return (error); 1611 error = callback(file, i, &symval, opaque); 1612 if (error != 0) 1613 return (error); 1614 } 1615 } 1616 return (0); 1617 } 1618 1619 const Elf_Sym * 1620 elf_get_sym(linker_file_t lf, Elf_Size symidx) 1621 { 1622 elf_file_t ef = (elf_file_t)lf; 1623 1624 if (symidx >= ef->nchains) 1625 return (NULL); 1626 return (ef->symtab + symidx); 1627 } 1628 1629 const char * 1630 elf_get_symname(linker_file_t lf, Elf_Size symidx) 1631 { 1632 elf_file_t ef = (elf_file_t)lf; 1633 const Elf_Sym *sym; 1634 1635 if (symidx >= ef->nchains) 1636 return (NULL); 1637 sym = ef->symtab + symidx; 1638 return (ef->strtab + sym->st_name); 1639 } 1640 1641 /* 1642 * Symbol lookup function that can be used when the symbol index is known (ie 1643 * in relocations). It uses the symbol index instead of doing a fully fledged 1644 * hash table based lookup when such is valid. For example for local symbols. 1645 * This is not only more efficient, it's also more correct. It's not always 1646 * the case that the symbol can be found through the hash table. 1647 */ 1648 static int 1649 elf_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res) 1650 { 1651 elf_file_t ef = (elf_file_t)lf; 1652 const Elf_Sym *sym; 1653 const char *symbol; 1654 Elf_Addr addr, start, base; 1655 1656 /* Don't even try to lookup the symbol if the index is bogus. */ 1657 if (symidx >= ef->nchains) { 1658 *res = 0; 1659 return (EINVAL); 1660 } 1661 1662 sym = ef->symtab + symidx; 1663 1664 /* 1665 * Don't do a full lookup when the symbol is local. It may even 1666 * fail because it may not be found through the hash table. 1667 */ 1668 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) { 1669 /* Force lookup failure when we have an insanity. */ 1670 if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0) { 1671 *res = 0; 1672 return (EINVAL); 1673 } 1674 *res = ((Elf_Addr)ef->address + sym->st_value); 1675 return (0); 1676 } 1677 1678 /* 1679 * XXX we can avoid doing a hash table based lookup for global 1680 * symbols as well. This however is not always valid, so we'll 1681 * just do it the hard way for now. Performance tweaks can 1682 * always be added. 1683 */ 1684 1685 symbol = ef->strtab + sym->st_name; 1686 1687 /* Force a lookup failure if the symbol name is bogus. */ 1688 if (*symbol == 0) { 1689 *res = 0; 1690 return (EINVAL); 1691 } 1692 1693 addr = ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps)); 1694 if (addr == 0 && ELF_ST_BIND(sym->st_info) != STB_WEAK) { 1695 *res = 0; 1696 return (EINVAL); 1697 } 1698 1699 if (elf_set_find(&set_pcpu_list, addr, &start, &base)) 1700 addr = addr - start + base; 1701 #ifdef VIMAGE 1702 else if (elf_set_find(&set_vnet_list, addr, &start, &base)) 1703 addr = addr - start + base; 1704 #endif 1705 *res = addr; 1706 return (0); 1707 } 1708 1709 static void 1710 link_elf_reloc_local(linker_file_t lf) 1711 { 1712 const Elf_Rel *rellim; 1713 const Elf_Rel *rel; 1714 const Elf_Rela *relalim; 1715 const Elf_Rela *rela; 1716 elf_file_t ef = (elf_file_t)lf; 1717 1718 /* Perform relocations without addend if there are any: */ 1719 if ((rel = ef->rel) != NULL) { 1720 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize); 1721 while (rel < rellim) { 1722 elf_reloc_local(lf, (Elf_Addr)ef->address, rel, 1723 ELF_RELOC_REL, elf_lookup); 1724 rel++; 1725 } 1726 } 1727 1728 /* Perform relocations with addend if there are any: */ 1729 if ((rela = ef->rela) != NULL) { 1730 relalim = (const Elf_Rela *) 1731 ((const char *)ef->rela + ef->relasize); 1732 while (rela < relalim) { 1733 elf_reloc_local(lf, (Elf_Addr)ef->address, rela, 1734 ELF_RELOC_RELA, elf_lookup); 1735 rela++; 1736 } 1737 } 1738 } 1739 1740 static long 1741 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab) 1742 { 1743 elf_file_t ef = (elf_file_t)lf; 1744 1745 *symtab = ef->ddbsymtab; 1746 1747 if (*symtab == NULL) 1748 return (0); 1749 1750 return (ef->ddbsymcnt); 1751 } 1752 1753 static long 1754 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab) 1755 { 1756 elf_file_t ef = (elf_file_t)lf; 1757 1758 *strtab = ef->ddbstrtab; 1759 1760 if (*strtab == NULL) 1761 return (0); 1762 1763 return (ef->ddbstrcnt); 1764 } 1765 1766 #if defined(__i386__) || defined(__amd64__) || defined(__aarch64__) 1767 /* 1768 * Use this lookup routine when performing relocations early during boot. 1769 * The generic lookup routine depends on kobj, which is not initialized 1770 * at that point. 1771 */ 1772 static int 1773 elf_lookup_ifunc(linker_file_t lf, Elf_Size symidx, int deps __unused, 1774 Elf_Addr *res) 1775 { 1776 elf_file_t ef; 1777 const Elf_Sym *symp; 1778 caddr_t val; 1779 1780 ef = (elf_file_t)lf; 1781 symp = ef->symtab + symidx; 1782 if (ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC) { 1783 val = (caddr_t)ef->address + symp->st_value; 1784 *res = ((Elf_Addr (*)(void))val)(); 1785 return (0); 1786 } 1787 return (ENOENT); 1788 } 1789 1790 void 1791 link_elf_ireloc(caddr_t kmdp) 1792 { 1793 struct elf_file eff; 1794 elf_file_t ef; 1795 1796 ef = &eff; 1797 1798 bzero_early(ef, sizeof(*ef)); 1799 1800 ef->modptr = kmdp; 1801 ef->dynamic = (Elf_Dyn *)&_DYNAMIC; 1802 parse_dynamic(ef); 1803 ef->address = 0; 1804 link_elf_preload_parse_symbols(ef); 1805 relocate_file1(ef, elf_lookup_ifunc, elf_reloc, true); 1806 } 1807 #endif
Cache object: 7b5f76ceb49185f9645847a986333b75
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