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 elf_cpu_parse_dynamic(&ef->lf, ef->dynamic); 615 } 616 617 #define LS_PADDING 0x90909090 618 static int 619 parse_dpcpu(elf_file_t ef) 620 { 621 int error, size; 622 #if defined(__i386__) 623 uint32_t pad; 624 #endif 625 626 ef->pcpu_start = 0; 627 ef->pcpu_stop = 0; 628 error = link_elf_lookup_set(&ef->lf, "pcpu", (void ***)&ef->pcpu_start, 629 (void ***)&ef->pcpu_stop, NULL); 630 /* Error just means there is no pcpu set to relocate. */ 631 if (error != 0) 632 return (0); 633 size = (uintptr_t)ef->pcpu_stop - (uintptr_t)ef->pcpu_start; 634 /* Empty set? */ 635 if (size < 1) 636 return (0); 637 #if defined(__i386__) 638 /* In case we do find __start/stop_set_ symbols double-check. */ 639 if (size < 4) { 640 uprintf("Kernel module '%s' must be recompiled with " 641 "linker script\n", ef->lf.pathname); 642 return (ENOEXEC); 643 } 644 645 /* Padding from linker-script correct? */ 646 pad = *(uint32_t *)((uintptr_t)ef->pcpu_stop - sizeof(pad)); 647 if (pad != LS_PADDING) { 648 uprintf("Kernel module '%s' must be recompiled with " 649 "linker script, invalid padding %#04x (%#04x)\n", 650 ef->lf.pathname, pad, LS_PADDING); 651 return (ENOEXEC); 652 } 653 /* If we only have valid padding, nothing to do. */ 654 if (size == 4) 655 return (0); 656 #endif 657 /* 658 * Allocate space in the primary pcpu area. Copy in our 659 * initialization from the data section and then initialize 660 * all per-cpu storage from that. 661 */ 662 ef->pcpu_base = (Elf_Addr)(uintptr_t)dpcpu_alloc(size); 663 if (ef->pcpu_base == 0) { 664 printf("%s: pcpu module space is out of space; " 665 "cannot allocate %d for %s\n", 666 __func__, size, ef->lf.pathname); 667 return (ENOSPC); 668 } 669 memcpy((void *)ef->pcpu_base, (void *)ef->pcpu_start, size); 670 dpcpu_copy((void *)ef->pcpu_base, size); 671 elf_set_add(&set_pcpu_list, ef->pcpu_start, ef->pcpu_stop, 672 ef->pcpu_base); 673 674 return (0); 675 } 676 677 #ifdef VIMAGE 678 static int 679 parse_vnet(elf_file_t ef) 680 { 681 int error, size; 682 #if defined(__i386__) 683 uint32_t pad; 684 #endif 685 686 ef->vnet_start = 0; 687 ef->vnet_stop = 0; 688 error = link_elf_lookup_set(&ef->lf, "vnet", (void ***)&ef->vnet_start, 689 (void ***)&ef->vnet_stop, NULL); 690 /* Error just means there is no vnet data set to relocate. */ 691 if (error != 0) 692 return (0); 693 size = (uintptr_t)ef->vnet_stop - (uintptr_t)ef->vnet_start; 694 /* Empty set? */ 695 if (size < 1) 696 return (0); 697 #if defined(__i386__) 698 /* In case we do find __start/stop_set_ symbols double-check. */ 699 if (size < 4) { 700 uprintf("Kernel module '%s' must be recompiled with " 701 "linker script\n", ef->lf.pathname); 702 return (ENOEXEC); 703 } 704 705 /* Padding from linker-script correct? */ 706 pad = *(uint32_t *)((uintptr_t)ef->vnet_stop - sizeof(pad)); 707 if (pad != LS_PADDING) { 708 uprintf("Kernel module '%s' must be recompiled with " 709 "linker script, invalid padding %#04x (%#04x)\n", 710 ef->lf.pathname, pad, LS_PADDING); 711 return (ENOEXEC); 712 } 713 /* If we only have valid padding, nothing to do. */ 714 if (size == 4) 715 return (0); 716 #endif 717 /* 718 * Allocate space in the primary vnet area. Copy in our 719 * initialization from the data section and then initialize 720 * all per-vnet storage from that. 721 */ 722 ef->vnet_base = (Elf_Addr)(uintptr_t)vnet_data_alloc(size); 723 if (ef->vnet_base == 0) { 724 printf("%s: vnet module space is out of space; " 725 "cannot allocate %d for %s\n", 726 __func__, size, ef->lf.pathname); 727 return (ENOSPC); 728 } 729 memcpy((void *)ef->vnet_base, (void *)ef->vnet_start, size); 730 vnet_data_copy((void *)ef->vnet_base, size); 731 elf_set_add(&set_vnet_list, ef->vnet_start, ef->vnet_stop, 732 ef->vnet_base); 733 734 return (0); 735 } 736 #endif 737 #undef LS_PADDING 738 739 /* 740 * Apply the specified protection to the loadable segments of a preloaded linker 741 * file. 742 */ 743 static int 744 preload_protect(elf_file_t ef, vm_prot_t prot) 745 { 746 #ifdef __amd64__ 747 Elf_Ehdr *hdr; 748 Elf_Phdr *phdr, *phlimit; 749 vm_prot_t nprot; 750 int error; 751 752 error = 0; 753 hdr = (Elf_Ehdr *)ef->address; 754 phdr = (Elf_Phdr *)(ef->address + hdr->e_phoff); 755 phlimit = phdr + hdr->e_phnum; 756 for (; phdr < phlimit; phdr++) { 757 if (phdr->p_type != PT_LOAD) 758 continue; 759 760 nprot = prot | VM_PROT_READ; 761 if ((phdr->p_flags & PF_W) != 0) 762 nprot |= VM_PROT_WRITE; 763 if ((phdr->p_flags & PF_X) != 0) 764 nprot |= VM_PROT_EXECUTE; 765 error = pmap_change_prot((vm_offset_t)ef->address + 766 phdr->p_vaddr, round_page(phdr->p_memsz), nprot); 767 if (error != 0) 768 break; 769 } 770 return (error); 771 #else 772 return (0); 773 #endif 774 } 775 776 #ifdef __arm__ 777 /* 778 * Locate the ARM exception/unwind table info for DDB and stack(9) use by 779 * searching for the section header that describes it. There may be no unwind 780 * info, for example in a module containing only data. 781 */ 782 static void 783 link_elf_locate_exidx(linker_file_t lf, Elf_Shdr *shdr, int nhdr) 784 { 785 int i; 786 787 for (i = 0; i < nhdr; i++) { 788 if (shdr[i].sh_type == SHT_ARM_EXIDX) { 789 lf->exidx_addr = shdr[i].sh_addr + lf->address; 790 lf->exidx_size = shdr[i].sh_size; 791 break; 792 } 793 } 794 } 795 796 /* 797 * Locate the section headers metadata in a preloaded module, then use it to 798 * locate the exception/unwind table in the module. The size of the metadata 799 * block is stored in a uint32 word immediately before the data itself, and a 800 * comment in preload_search_info() says it is safe to rely on that. 801 */ 802 static void 803 link_elf_locate_exidx_preload(struct linker_file *lf, caddr_t modptr) 804 { 805 uint32_t *modinfo; 806 Elf_Shdr *shdr; 807 uint32_t nhdr; 808 809 modinfo = (uint32_t *)preload_search_info(modptr, 810 MODINFO_METADATA | MODINFOMD_SHDR); 811 if (modinfo != NULL) { 812 shdr = (Elf_Shdr *)modinfo; 813 nhdr = modinfo[-1] / sizeof(Elf_Shdr); 814 link_elf_locate_exidx(lf, shdr, nhdr); 815 } 816 } 817 818 #endif /* __arm__ */ 819 820 static int 821 link_elf_link_preload(linker_class_t cls, const char *filename, 822 linker_file_t *result) 823 { 824 Elf_Addr *ctors_addrp; 825 Elf_Size *ctors_sizep; 826 caddr_t modptr, baseptr, sizeptr, dynptr; 827 char *type; 828 elf_file_t ef; 829 linker_file_t lf; 830 int error; 831 vm_offset_t dp; 832 833 /* Look to see if we have the file preloaded */ 834 modptr = preload_search_by_name(filename); 835 if (modptr == NULL) 836 return (ENOENT); 837 838 type = (char *)preload_search_info(modptr, MODINFO_TYPE); 839 baseptr = preload_search_info(modptr, MODINFO_ADDR); 840 sizeptr = preload_search_info(modptr, MODINFO_SIZE); 841 dynptr = preload_search_info(modptr, 842 MODINFO_METADATA | MODINFOMD_DYNAMIC); 843 if (type == NULL || 844 (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) " module") != 0 && 845 strcmp(type, "elf module") != 0)) 846 return (EFTYPE); 847 if (baseptr == NULL || sizeptr == NULL || dynptr == NULL) 848 return (EINVAL); 849 850 lf = linker_make_file(filename, &link_elf_class); 851 if (lf == NULL) 852 return (ENOMEM); 853 854 ef = (elf_file_t) lf; 855 ef->preloaded = 1; 856 ef->modptr = modptr; 857 ef->address = *(caddr_t *)baseptr; 858 #ifdef SPARSE_MAPPING 859 ef->object = NULL; 860 #endif 861 dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr; 862 ef->dynamic = (Elf_Dyn *)dp; 863 lf->address = ef->address; 864 lf->size = *(size_t *)sizeptr; 865 866 ctors_addrp = (Elf_Addr *)preload_search_info(modptr, 867 MODINFO_METADATA | MODINFOMD_CTORS_ADDR); 868 ctors_sizep = (Elf_Size *)preload_search_info(modptr, 869 MODINFO_METADATA | MODINFOMD_CTORS_SIZE); 870 if (ctors_addrp != NULL && ctors_sizep != NULL) { 871 lf->ctors_addr = ef->address + *ctors_addrp; 872 lf->ctors_size = *ctors_sizep; 873 } 874 875 #ifdef __arm__ 876 link_elf_locate_exidx_preload(lf, modptr); 877 #endif 878 879 error = parse_dynamic(ef); 880 if (error == 0) 881 error = parse_dpcpu(ef); 882 #ifdef VIMAGE 883 if (error == 0) 884 error = parse_vnet(ef); 885 #endif 886 if (error == 0) 887 error = preload_protect(ef, VM_PROT_ALL); 888 if (error != 0) { 889 linker_file_unload(lf, LINKER_UNLOAD_FORCE); 890 return (error); 891 } 892 link_elf_reloc_local(lf); 893 *result = lf; 894 return (0); 895 } 896 897 static int 898 link_elf_link_preload_finish(linker_file_t lf) 899 { 900 elf_file_t ef; 901 int error; 902 903 ef = (elf_file_t) lf; 904 error = relocate_file(ef); 905 if (error == 0) 906 error = preload_protect(ef, VM_PROT_NONE); 907 if (error != 0) 908 return (error); 909 (void)link_elf_preload_parse_symbols(ef); 910 911 return (link_elf_link_common_finish(lf)); 912 } 913 914 static int 915 link_elf_load_file(linker_class_t cls, const char* filename, 916 linker_file_t* result) 917 { 918 struct nameidata nd; 919 struct thread* td = curthread; /* XXX */ 920 Elf_Ehdr *hdr; 921 caddr_t firstpage, segbase; 922 int nbytes, i; 923 Elf_Phdr *phdr; 924 Elf_Phdr *phlimit; 925 Elf_Phdr *segs[MAXSEGS]; 926 int nsegs; 927 Elf_Phdr *phdyn; 928 caddr_t mapbase; 929 size_t mapsize; 930 Elf_Addr base_vaddr; 931 Elf_Addr base_vlimit; 932 int error = 0; 933 ssize_t resid; 934 int flags; 935 elf_file_t ef; 936 linker_file_t lf; 937 Elf_Shdr *shdr; 938 int symtabindex; 939 int symstrindex; 940 int shstrindex; 941 int symcnt; 942 int strcnt; 943 char *shstrs; 944 945 shdr = NULL; 946 lf = NULL; 947 shstrs = NULL; 948 949 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td); 950 flags = FREAD; 951 error = vn_open(&nd, &flags, 0, NULL); 952 if (error != 0) 953 return (error); 954 NDFREE(&nd, NDF_ONLY_PNBUF); 955 if (nd.ni_vp->v_type != VREG) { 956 error = ENOEXEC; 957 firstpage = NULL; 958 goto out; 959 } 960 #ifdef MAC 961 error = mac_kld_check_load(curthread->td_ucred, nd.ni_vp); 962 if (error != 0) { 963 firstpage = NULL; 964 goto out; 965 } 966 #endif 967 968 /* 969 * Read the elf header from the file. 970 */ 971 firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK); 972 hdr = (Elf_Ehdr *)firstpage; 973 error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0, 974 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 975 &resid, td); 976 nbytes = PAGE_SIZE - resid; 977 if (error != 0) 978 goto out; 979 980 if (!IS_ELF(*hdr)) { 981 error = ENOEXEC; 982 goto out; 983 } 984 985 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS || 986 hdr->e_ident[EI_DATA] != ELF_TARG_DATA) { 987 link_elf_error(filename, "Unsupported file layout"); 988 error = ENOEXEC; 989 goto out; 990 } 991 if (hdr->e_ident[EI_VERSION] != EV_CURRENT || 992 hdr->e_version != EV_CURRENT) { 993 link_elf_error(filename, "Unsupported file version"); 994 error = ENOEXEC; 995 goto out; 996 } 997 if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) { 998 error = ENOSYS; 999 goto out; 1000 } 1001 if (hdr->e_machine != ELF_TARG_MACH) { 1002 link_elf_error(filename, "Unsupported machine"); 1003 error = ENOEXEC; 1004 goto out; 1005 } 1006 1007 /* 1008 * We rely on the program header being in the first page. 1009 * This is not strictly required by the ABI specification, but 1010 * it seems to always true in practice. And, it simplifies 1011 * things considerably. 1012 */ 1013 if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) && 1014 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) && 1015 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes))) 1016 link_elf_error(filename, "Unreadable program headers"); 1017 1018 /* 1019 * Scan the program header entries, and save key information. 1020 * 1021 * We rely on there being exactly two load segments, text and data, 1022 * in that order. 1023 */ 1024 phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff); 1025 phlimit = phdr + hdr->e_phnum; 1026 nsegs = 0; 1027 phdyn = NULL; 1028 while (phdr < phlimit) { 1029 switch (phdr->p_type) { 1030 case PT_LOAD: 1031 if (nsegs == MAXSEGS) { 1032 link_elf_error(filename, "Too many sections"); 1033 error = ENOEXEC; 1034 goto out; 1035 } 1036 /* 1037 * XXX: We just trust they come in right order ?? 1038 */ 1039 segs[nsegs] = phdr; 1040 ++nsegs; 1041 break; 1042 1043 case PT_DYNAMIC: 1044 phdyn = phdr; 1045 break; 1046 1047 case PT_INTERP: 1048 error = ENOSYS; 1049 goto out; 1050 } 1051 1052 ++phdr; 1053 } 1054 if (phdyn == NULL) { 1055 link_elf_error(filename, "Object is not dynamically-linked"); 1056 error = ENOEXEC; 1057 goto out; 1058 } 1059 if (nsegs == 0) { 1060 link_elf_error(filename, "No sections"); 1061 error = ENOEXEC; 1062 goto out; 1063 } 1064 1065 /* 1066 * Allocate the entire address space of the object, to stake 1067 * out our contiguous region, and to establish the base 1068 * address for relocation. 1069 */ 1070 base_vaddr = trunc_page(segs[0]->p_vaddr); 1071 base_vlimit = round_page(segs[nsegs - 1]->p_vaddr + 1072 segs[nsegs - 1]->p_memsz); 1073 mapsize = base_vlimit - base_vaddr; 1074 1075 lf = linker_make_file(filename, &link_elf_class); 1076 if (lf == NULL) { 1077 error = ENOMEM; 1078 goto out; 1079 } 1080 1081 ef = (elf_file_t) lf; 1082 #ifdef SPARSE_MAPPING 1083 ef->object = vm_object_allocate(OBJT_PHYS, atop(mapsize)); 1084 if (ef->object == NULL) { 1085 error = ENOMEM; 1086 goto out; 1087 } 1088 #ifdef __amd64__ 1089 mapbase = (caddr_t)KERNBASE; 1090 #else 1091 mapbase = (caddr_t)vm_map_min(kernel_map); 1092 #endif 1093 /* 1094 * Mapping protections are downgraded after relocation processing. 1095 */ 1096 error = vm_map_find(kernel_map, ef->object, 0, 1097 (vm_offset_t *)&mapbase, mapsize, 0, VMFS_OPTIMAL_SPACE, 1098 VM_PROT_ALL, VM_PROT_ALL, 0); 1099 if (error != 0) { 1100 vm_object_deallocate(ef->object); 1101 ef->object = NULL; 1102 goto out; 1103 } 1104 #else 1105 mapbase = malloc(mapsize, M_LINKER, M_EXEC | M_WAITOK); 1106 #endif 1107 ef->address = mapbase; 1108 1109 /* 1110 * Read the text and data sections and zero the bss. 1111 */ 1112 for (i = 0; i < nsegs; i++) { 1113 segbase = mapbase + segs[i]->p_vaddr - base_vaddr; 1114 1115 #ifdef SPARSE_MAPPING 1116 /* 1117 * Consecutive segments may have different mapping permissions, 1118 * so be strict and verify that their mappings do not overlap. 1119 */ 1120 if (((vm_offset_t)segbase & PAGE_MASK) != 0) { 1121 error = EINVAL; 1122 goto out; 1123 } 1124 1125 error = vm_map_wire(kernel_map, 1126 (vm_offset_t)segbase, 1127 (vm_offset_t)segbase + round_page(segs[i]->p_memsz), 1128 VM_MAP_WIRE_SYSTEM | VM_MAP_WIRE_NOHOLES); 1129 if (error != KERN_SUCCESS) { 1130 error = ENOMEM; 1131 goto out; 1132 } 1133 #endif 1134 1135 error = vn_rdwr(UIO_READ, nd.ni_vp, 1136 segbase, segs[i]->p_filesz, segs[i]->p_offset, 1137 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1138 &resid, td); 1139 if (error != 0) 1140 goto out; 1141 bzero(segbase + segs[i]->p_filesz, 1142 segs[i]->p_memsz - segs[i]->p_filesz); 1143 } 1144 1145 #ifdef GPROF 1146 /* Update profiling information with the new text segment. */ 1147 mtx_lock(&Giant); 1148 kmupetext((uintfptr_t)(mapbase + segs[0]->p_vaddr - base_vaddr + 1149 segs[0]->p_memsz)); 1150 mtx_unlock(&Giant); 1151 #endif 1152 1153 ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr); 1154 1155 lf->address = ef->address; 1156 lf->size = mapsize; 1157 1158 error = parse_dynamic(ef); 1159 if (error != 0) 1160 goto out; 1161 error = parse_dpcpu(ef); 1162 if (error != 0) 1163 goto out; 1164 #ifdef VIMAGE 1165 error = parse_vnet(ef); 1166 if (error != 0) 1167 goto out; 1168 #endif 1169 link_elf_reloc_local(lf); 1170 1171 VOP_UNLOCK(nd.ni_vp); 1172 error = linker_load_dependencies(lf); 1173 vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY); 1174 if (error != 0) 1175 goto out; 1176 error = relocate_file(ef); 1177 if (error != 0) 1178 goto out; 1179 1180 #ifdef SPARSE_MAPPING 1181 /* 1182 * Downgrade permissions on text segment mappings now that relocation 1183 * processing is complete. Restrict permissions on read-only segments. 1184 */ 1185 for (i = 0; i < nsegs; i++) { 1186 vm_prot_t prot; 1187 1188 if (segs[i]->p_type != PT_LOAD) 1189 continue; 1190 1191 prot = VM_PROT_READ; 1192 if ((segs[i]->p_flags & PF_W) != 0) 1193 prot |= VM_PROT_WRITE; 1194 if ((segs[i]->p_flags & PF_X) != 0) 1195 prot |= VM_PROT_EXECUTE; 1196 segbase = mapbase + segs[i]->p_vaddr - base_vaddr; 1197 error = vm_map_protect(kernel_map, 1198 (vm_offset_t)segbase, 1199 (vm_offset_t)segbase + round_page(segs[i]->p_memsz), 1200 prot, FALSE); 1201 if (error != KERN_SUCCESS) { 1202 error = ENOMEM; 1203 goto out; 1204 } 1205 } 1206 #endif 1207 1208 /* 1209 * Try and load the symbol table if it's present. (you can 1210 * strip it!) 1211 */ 1212 nbytes = hdr->e_shnum * hdr->e_shentsize; 1213 if (nbytes == 0 || hdr->e_shoff == 0) 1214 goto nosyms; 1215 shdr = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO); 1216 error = vn_rdwr(UIO_READ, nd.ni_vp, 1217 (caddr_t)shdr, nbytes, hdr->e_shoff, 1218 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1219 &resid, td); 1220 if (error != 0) 1221 goto out; 1222 1223 /* Read section string table */ 1224 shstrindex = hdr->e_shstrndx; 1225 if (shstrindex != 0 && shdr[shstrindex].sh_type == SHT_STRTAB && 1226 shdr[shstrindex].sh_size != 0) { 1227 nbytes = shdr[shstrindex].sh_size; 1228 shstrs = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO); 1229 error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)shstrs, nbytes, 1230 shdr[shstrindex].sh_offset, UIO_SYSSPACE, IO_NODELOCKED, 1231 td->td_ucred, NOCRED, &resid, td); 1232 if (error) 1233 goto out; 1234 } 1235 1236 symtabindex = -1; 1237 symstrindex = -1; 1238 for (i = 0; i < hdr->e_shnum; i++) { 1239 if (shdr[i].sh_type == SHT_SYMTAB) { 1240 symtabindex = i; 1241 symstrindex = shdr[i].sh_link; 1242 } else if (shstrs != NULL && shdr[i].sh_name != 0 && 1243 strcmp(shstrs + shdr[i].sh_name, ".ctors") == 0) { 1244 /* Record relocated address and size of .ctors. */ 1245 lf->ctors_addr = mapbase + shdr[i].sh_addr - base_vaddr; 1246 lf->ctors_size = shdr[i].sh_size; 1247 } 1248 } 1249 if (symtabindex < 0 || symstrindex < 0) 1250 goto nosyms; 1251 1252 symcnt = shdr[symtabindex].sh_size; 1253 ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK); 1254 strcnt = shdr[symstrindex].sh_size; 1255 ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK); 1256 1257 error = vn_rdwr(UIO_READ, nd.ni_vp, 1258 ef->symbase, symcnt, shdr[symtabindex].sh_offset, 1259 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1260 &resid, td); 1261 if (error != 0) 1262 goto out; 1263 error = vn_rdwr(UIO_READ, nd.ni_vp, 1264 ef->strbase, strcnt, shdr[symstrindex].sh_offset, 1265 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1266 &resid, td); 1267 if (error != 0) 1268 goto out; 1269 1270 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym); 1271 ef->ddbsymtab = (const Elf_Sym *)ef->symbase; 1272 ef->ddbstrcnt = strcnt; 1273 ef->ddbstrtab = ef->strbase; 1274 1275 nosyms: 1276 1277 #ifdef __arm__ 1278 link_elf_locate_exidx(lf, shdr, hdr->e_shnum); 1279 #endif 1280 1281 error = link_elf_link_common_finish(lf); 1282 if (error != 0) 1283 goto out; 1284 1285 *result = lf; 1286 1287 out: 1288 VOP_UNLOCK(nd.ni_vp); 1289 vn_close(nd.ni_vp, FREAD, td->td_ucred, td); 1290 if (error != 0 && lf != NULL) 1291 linker_file_unload(lf, LINKER_UNLOAD_FORCE); 1292 free(shdr, M_LINKER); 1293 free(firstpage, M_LINKER); 1294 free(shstrs, M_LINKER); 1295 1296 return (error); 1297 } 1298 1299 Elf_Addr 1300 elf_relocaddr(linker_file_t lf, Elf_Addr x) 1301 { 1302 elf_file_t ef; 1303 1304 KASSERT(lf->ops->cls == (kobj_class_t)&link_elf_class, 1305 ("elf_relocaddr: unexpected linker file %p", lf)); 1306 1307 ef = (elf_file_t)lf; 1308 if (x >= ef->pcpu_start && x < ef->pcpu_stop) 1309 return ((x - ef->pcpu_start) + ef->pcpu_base); 1310 #ifdef VIMAGE 1311 if (x >= ef->vnet_start && x < ef->vnet_stop) 1312 return ((x - ef->vnet_start) + ef->vnet_base); 1313 #endif 1314 return (x); 1315 } 1316 1317 1318 static void 1319 link_elf_unload_file(linker_file_t file) 1320 { 1321 elf_file_t ef = (elf_file_t) file; 1322 1323 if (ef->pcpu_base != 0) { 1324 dpcpu_free((void *)ef->pcpu_base, 1325 ef->pcpu_stop - ef->pcpu_start); 1326 elf_set_delete(&set_pcpu_list, ef->pcpu_start); 1327 } 1328 #ifdef VIMAGE 1329 if (ef->vnet_base != 0) { 1330 vnet_data_free((void *)ef->vnet_base, 1331 ef->vnet_stop - ef->vnet_start); 1332 elf_set_delete(&set_vnet_list, ef->vnet_start); 1333 } 1334 #endif 1335 #ifdef GDB 1336 if (ef->gdb.l_ld != NULL) { 1337 GDB_STATE(RT_DELETE); 1338 free((void *)(uintptr_t)ef->gdb.l_name, M_LINKER); 1339 link_elf_delete_gdb(&ef->gdb); 1340 GDB_STATE(RT_CONSISTENT); 1341 } 1342 #endif 1343 1344 /* Notify MD code that a module is being unloaded. */ 1345 elf_cpu_unload_file(file); 1346 1347 if (ef->preloaded) { 1348 link_elf_unload_preload(file); 1349 return; 1350 } 1351 1352 #ifdef SPARSE_MAPPING 1353 if (ef->object != NULL) { 1354 vm_map_remove(kernel_map, (vm_offset_t) ef->address, 1355 (vm_offset_t) ef->address 1356 + (ef->object->size << PAGE_SHIFT)); 1357 } 1358 #else 1359 free(ef->address, M_LINKER); 1360 #endif 1361 free(ef->symbase, M_LINKER); 1362 free(ef->strbase, M_LINKER); 1363 free(ef->ctftab, M_LINKER); 1364 free(ef->ctfoff, M_LINKER); 1365 free(ef->typoff, M_LINKER); 1366 } 1367 1368 static void 1369 link_elf_unload_preload(linker_file_t file) 1370 { 1371 1372 if (file->pathname != NULL) 1373 preload_delete_name(file->pathname); 1374 } 1375 1376 static const char * 1377 symbol_name(elf_file_t ef, Elf_Size r_info) 1378 { 1379 const Elf_Sym *ref; 1380 1381 if (ELF_R_SYM(r_info)) { 1382 ref = ef->symtab + ELF_R_SYM(r_info); 1383 return (ef->strtab + ref->st_name); 1384 } 1385 return (NULL); 1386 } 1387 1388 static int 1389 symbol_type(elf_file_t ef, Elf_Size r_info) 1390 { 1391 const Elf_Sym *ref; 1392 1393 if (ELF_R_SYM(r_info)) { 1394 ref = ef->symtab + ELF_R_SYM(r_info); 1395 return (ELF_ST_TYPE(ref->st_info)); 1396 } 1397 return (STT_NOTYPE); 1398 } 1399 1400 static int 1401 relocate_file1(elf_file_t ef, elf_lookup_fn lookup, elf_reloc_fn reloc, 1402 bool ifuncs) 1403 { 1404 const Elf_Rel *rel; 1405 const Elf_Rela *rela; 1406 const char *symname; 1407 1408 #define APPLY_RELOCS(iter, tbl, tblsize, type) do { \ 1409 for ((iter) = (tbl); (iter) != NULL && \ 1410 (iter) < (tbl) + (tblsize) / sizeof(*(iter)); (iter)++) { \ 1411 if ((symbol_type(ef, (iter)->r_info) == \ 1412 STT_GNU_IFUNC || \ 1413 elf_is_ifunc_reloc((iter)->r_info)) != ifuncs) \ 1414 continue; \ 1415 if (reloc(&ef->lf, (Elf_Addr)ef->address, \ 1416 (iter), (type), lookup)) { \ 1417 symname = symbol_name(ef, (iter)->r_info); \ 1418 printf("link_elf: symbol %s undefined\n", \ 1419 symname); \ 1420 return (ENOENT); \ 1421 } \ 1422 } \ 1423 } while (0) 1424 1425 APPLY_RELOCS(rel, ef->rel, ef->relsize, ELF_RELOC_REL); 1426 APPLY_RELOCS(rela, ef->rela, ef->relasize, ELF_RELOC_RELA); 1427 APPLY_RELOCS(rel, ef->pltrel, ef->pltrelsize, ELF_RELOC_REL); 1428 APPLY_RELOCS(rela, ef->pltrela, ef->pltrelasize, ELF_RELOC_RELA); 1429 1430 #undef APPLY_RELOCS 1431 1432 return (0); 1433 } 1434 1435 static int 1436 relocate_file(elf_file_t ef) 1437 { 1438 int error; 1439 1440 error = relocate_file1(ef, elf_lookup, elf_reloc, false); 1441 if (error == 0) 1442 error = relocate_file1(ef, elf_lookup, elf_reloc, true); 1443 return (error); 1444 } 1445 1446 /* 1447 * Hash function for symbol table lookup. Don't even think about changing 1448 * this. It is specified by the System V ABI. 1449 */ 1450 static unsigned long 1451 elf_hash(const char *name) 1452 { 1453 const unsigned char *p = (const unsigned char *) name; 1454 unsigned long h = 0; 1455 unsigned long g; 1456 1457 while (*p != '\0') { 1458 h = (h << 4) + *p++; 1459 if ((g = h & 0xf0000000) != 0) 1460 h ^= g >> 24; 1461 h &= ~g; 1462 } 1463 return (h); 1464 } 1465 1466 static int 1467 link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym) 1468 { 1469 elf_file_t ef = (elf_file_t) lf; 1470 unsigned long symnum; 1471 const Elf_Sym* symp; 1472 const char *strp; 1473 unsigned long hash; 1474 int i; 1475 1476 /* If we don't have a hash, bail. */ 1477 if (ef->buckets == NULL || ef->nbuckets == 0) { 1478 printf("link_elf_lookup_symbol: missing symbol hash table\n"); 1479 return (ENOENT); 1480 } 1481 1482 /* First, search hashed global symbols */ 1483 hash = elf_hash(name); 1484 symnum = ef->buckets[hash % ef->nbuckets]; 1485 1486 while (symnum != STN_UNDEF) { 1487 if (symnum >= ef->nchains) { 1488 printf("%s: corrupt symbol table\n", __func__); 1489 return (ENOENT); 1490 } 1491 1492 symp = ef->symtab + symnum; 1493 if (symp->st_name == 0) { 1494 printf("%s: corrupt symbol table\n", __func__); 1495 return (ENOENT); 1496 } 1497 1498 strp = ef->strtab + symp->st_name; 1499 1500 if (strcmp(name, strp) == 0) { 1501 if (symp->st_shndx != SHN_UNDEF || 1502 (symp->st_value != 0 && 1503 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1504 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC))) { 1505 *sym = (c_linker_sym_t) symp; 1506 return (0); 1507 } 1508 return (ENOENT); 1509 } 1510 1511 symnum = ef->chains[symnum]; 1512 } 1513 1514 /* If we have not found it, look at the full table (if loaded) */ 1515 if (ef->symtab == ef->ddbsymtab) 1516 return (ENOENT); 1517 1518 /* Exhaustive search */ 1519 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1520 strp = ef->ddbstrtab + symp->st_name; 1521 if (strcmp(name, strp) == 0) { 1522 if (symp->st_shndx != SHN_UNDEF || 1523 (symp->st_value != 0 && 1524 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1525 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC))) { 1526 *sym = (c_linker_sym_t) symp; 1527 return (0); 1528 } 1529 return (ENOENT); 1530 } 1531 } 1532 1533 return (ENOENT); 1534 } 1535 1536 static int 1537 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, 1538 linker_symval_t *symval) 1539 { 1540 elf_file_t ef; 1541 const Elf_Sym *es; 1542 caddr_t val; 1543 1544 ef = (elf_file_t)lf; 1545 es = (const Elf_Sym *)sym; 1546 if (es >= ef->symtab && es < (ef->symtab + ef->nchains)) { 1547 symval->name = ef->strtab + es->st_name; 1548 val = (caddr_t)ef->address + es->st_value; 1549 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC) 1550 val = ((caddr_t (*)(void))val)(); 1551 symval->value = val; 1552 symval->size = es->st_size; 1553 return (0); 1554 } 1555 if (ef->symtab == ef->ddbsymtab) 1556 return (ENOENT); 1557 if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) { 1558 symval->name = ef->ddbstrtab + es->st_name; 1559 val = (caddr_t)ef->address + es->st_value; 1560 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC) 1561 val = ((caddr_t (*)(void))val)(); 1562 symval->value = val; 1563 symval->size = es->st_size; 1564 return (0); 1565 } 1566 return (ENOENT); 1567 } 1568 1569 static int 1570 link_elf_search_symbol(linker_file_t lf, caddr_t value, 1571 c_linker_sym_t *sym, long *diffp) 1572 { 1573 elf_file_t ef = (elf_file_t) lf; 1574 u_long off = (uintptr_t) (void *) value; 1575 u_long diff = off; 1576 u_long st_value; 1577 const Elf_Sym* es; 1578 const Elf_Sym* best = NULL; 1579 int i; 1580 1581 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) { 1582 if (es->st_name == 0) 1583 continue; 1584 st_value = es->st_value + (uintptr_t) (void *) ef->address; 1585 if (off >= st_value) { 1586 if (off - st_value < diff) { 1587 diff = off - st_value; 1588 best = es; 1589 if (diff == 0) 1590 break; 1591 } else if (off - st_value == diff) { 1592 best = es; 1593 } 1594 } 1595 } 1596 if (best == NULL) 1597 *diffp = off; 1598 else 1599 *diffp = diff; 1600 *sym = (c_linker_sym_t) best; 1601 1602 return (0); 1603 } 1604 1605 /* 1606 * Look up a linker set on an ELF system. 1607 */ 1608 static int 1609 link_elf_lookup_set(linker_file_t lf, const char *name, 1610 void ***startp, void ***stopp, int *countp) 1611 { 1612 c_linker_sym_t sym; 1613 linker_symval_t symval; 1614 char *setsym; 1615 void **start, **stop; 1616 int len, error = 0, count; 1617 1618 len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */ 1619 setsym = malloc(len, M_LINKER, M_WAITOK); 1620 1621 /* get address of first entry */ 1622 snprintf(setsym, len, "%s%s", "__start_set_", name); 1623 error = link_elf_lookup_symbol(lf, setsym, &sym); 1624 if (error != 0) 1625 goto out; 1626 link_elf_symbol_values(lf, sym, &symval); 1627 if (symval.value == 0) { 1628 error = ESRCH; 1629 goto out; 1630 } 1631 start = (void **)symval.value; 1632 1633 /* get address of last entry */ 1634 snprintf(setsym, len, "%s%s", "__stop_set_", name); 1635 error = link_elf_lookup_symbol(lf, setsym, &sym); 1636 if (error != 0) 1637 goto out; 1638 link_elf_symbol_values(lf, sym, &symval); 1639 if (symval.value == 0) { 1640 error = ESRCH; 1641 goto out; 1642 } 1643 stop = (void **)symval.value; 1644 1645 /* and the number of entries */ 1646 count = stop - start; 1647 1648 /* and copy out */ 1649 if (startp != NULL) 1650 *startp = start; 1651 if (stopp != NULL) 1652 *stopp = stop; 1653 if (countp != NULL) 1654 *countp = count; 1655 1656 out: 1657 free(setsym, M_LINKER); 1658 return (error); 1659 } 1660 1661 static int 1662 link_elf_each_function_name(linker_file_t file, 1663 int (*callback)(const char *, void *), void *opaque) 1664 { 1665 elf_file_t ef = (elf_file_t)file; 1666 const Elf_Sym *symp; 1667 int i, error; 1668 1669 /* Exhaustive search */ 1670 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1671 if (symp->st_value != 0 && 1672 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1673 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) { 1674 error = callback(ef->ddbstrtab + symp->st_name, opaque); 1675 if (error != 0) 1676 return (error); 1677 } 1678 } 1679 return (0); 1680 } 1681 1682 static int 1683 link_elf_each_function_nameval(linker_file_t file, 1684 linker_function_nameval_callback_t callback, void *opaque) 1685 { 1686 linker_symval_t symval; 1687 elf_file_t ef = (elf_file_t)file; 1688 const Elf_Sym* symp; 1689 int i, error; 1690 1691 /* Exhaustive search */ 1692 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1693 if (symp->st_value != 0 && 1694 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1695 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) { 1696 error = link_elf_symbol_values(file, 1697 (c_linker_sym_t) symp, &symval); 1698 if (error != 0) 1699 return (error); 1700 error = callback(file, i, &symval, opaque); 1701 if (error != 0) 1702 return (error); 1703 } 1704 } 1705 return (0); 1706 } 1707 1708 const Elf_Sym * 1709 elf_get_sym(linker_file_t lf, Elf_Size symidx) 1710 { 1711 elf_file_t ef = (elf_file_t)lf; 1712 1713 if (symidx >= ef->nchains) 1714 return (NULL); 1715 return (ef->symtab + symidx); 1716 } 1717 1718 const char * 1719 elf_get_symname(linker_file_t lf, Elf_Size symidx) 1720 { 1721 elf_file_t ef = (elf_file_t)lf; 1722 const Elf_Sym *sym; 1723 1724 if (symidx >= ef->nchains) 1725 return (NULL); 1726 sym = ef->symtab + symidx; 1727 return (ef->strtab + sym->st_name); 1728 } 1729 1730 /* 1731 * Symbol lookup function that can be used when the symbol index is known (ie 1732 * in relocations). It uses the symbol index instead of doing a fully fledged 1733 * hash table based lookup when such is valid. For example for local symbols. 1734 * This is not only more efficient, it's also more correct. It's not always 1735 * the case that the symbol can be found through the hash table. 1736 */ 1737 static int 1738 elf_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res) 1739 { 1740 elf_file_t ef = (elf_file_t)lf; 1741 const Elf_Sym *sym; 1742 const char *symbol; 1743 Elf_Addr addr, start, base; 1744 1745 /* Don't even try to lookup the symbol if the index is bogus. */ 1746 if (symidx >= ef->nchains) { 1747 *res = 0; 1748 return (EINVAL); 1749 } 1750 1751 sym = ef->symtab + symidx; 1752 1753 /* 1754 * Don't do a full lookup when the symbol is local. It may even 1755 * fail because it may not be found through the hash table. 1756 */ 1757 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) { 1758 /* Force lookup failure when we have an insanity. */ 1759 if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0) { 1760 *res = 0; 1761 return (EINVAL); 1762 } 1763 *res = ((Elf_Addr)ef->address + sym->st_value); 1764 return (0); 1765 } 1766 1767 /* 1768 * XXX we can avoid doing a hash table based lookup for global 1769 * symbols as well. This however is not always valid, so we'll 1770 * just do it the hard way for now. Performance tweaks can 1771 * always be added. 1772 */ 1773 1774 symbol = ef->strtab + sym->st_name; 1775 1776 /* Force a lookup failure if the symbol name is bogus. */ 1777 if (*symbol == 0) { 1778 *res = 0; 1779 return (EINVAL); 1780 } 1781 1782 addr = ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps)); 1783 if (addr == 0 && ELF_ST_BIND(sym->st_info) != STB_WEAK) { 1784 *res = 0; 1785 return (EINVAL); 1786 } 1787 1788 if (elf_set_find(&set_pcpu_list, addr, &start, &base)) 1789 addr = addr - start + base; 1790 #ifdef VIMAGE 1791 else if (elf_set_find(&set_vnet_list, addr, &start, &base)) 1792 addr = addr - start + base; 1793 #endif 1794 *res = addr; 1795 return (0); 1796 } 1797 1798 static void 1799 link_elf_reloc_local(linker_file_t lf) 1800 { 1801 const Elf_Rel *rellim; 1802 const Elf_Rel *rel; 1803 const Elf_Rela *relalim; 1804 const Elf_Rela *rela; 1805 elf_file_t ef = (elf_file_t)lf; 1806 1807 /* Perform relocations without addend if there are any: */ 1808 if ((rel = ef->rel) != NULL) { 1809 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize); 1810 while (rel < rellim) { 1811 elf_reloc_local(lf, (Elf_Addr)ef->address, rel, 1812 ELF_RELOC_REL, elf_lookup); 1813 rel++; 1814 } 1815 } 1816 1817 /* Perform relocations with addend if there are any: */ 1818 if ((rela = ef->rela) != NULL) { 1819 relalim = (const Elf_Rela *) 1820 ((const char *)ef->rela + ef->relasize); 1821 while (rela < relalim) { 1822 elf_reloc_local(lf, (Elf_Addr)ef->address, rela, 1823 ELF_RELOC_RELA, elf_lookup); 1824 rela++; 1825 } 1826 } 1827 } 1828 1829 static long 1830 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab) 1831 { 1832 elf_file_t ef = (elf_file_t)lf; 1833 1834 *symtab = ef->ddbsymtab; 1835 1836 if (*symtab == NULL) 1837 return (0); 1838 1839 return (ef->ddbsymcnt); 1840 } 1841 1842 static long 1843 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab) 1844 { 1845 elf_file_t ef = (elf_file_t)lf; 1846 1847 *strtab = ef->ddbstrtab; 1848 1849 if (*strtab == NULL) 1850 return (0); 1851 1852 return (ef->ddbstrcnt); 1853 } 1854 1855 #if defined(__i386__) || defined(__amd64__) || defined(__aarch64__) 1856 /* 1857 * Use this lookup routine when performing relocations early during boot. 1858 * The generic lookup routine depends on kobj, which is not initialized 1859 * at that point. 1860 */ 1861 static int 1862 elf_lookup_ifunc(linker_file_t lf, Elf_Size symidx, int deps __unused, 1863 Elf_Addr *res) 1864 { 1865 elf_file_t ef; 1866 const Elf_Sym *symp; 1867 caddr_t val; 1868 1869 ef = (elf_file_t)lf; 1870 symp = ef->symtab + symidx; 1871 if (ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC) { 1872 val = (caddr_t)ef->address + symp->st_value; 1873 *res = ((Elf_Addr (*)(void))val)(); 1874 return (0); 1875 } 1876 return (ENOENT); 1877 } 1878 1879 void 1880 link_elf_ireloc(caddr_t kmdp) 1881 { 1882 struct elf_file eff; 1883 elf_file_t ef; 1884 1885 ef = &eff; 1886 1887 bzero_early(ef, sizeof(*ef)); 1888 1889 ef->modptr = kmdp; 1890 ef->dynamic = (Elf_Dyn *)&_DYNAMIC; 1891 parse_dynamic(ef); 1892 ef->address = 0; 1893 link_elf_preload_parse_symbols(ef); 1894 relocate_file1(ef, elf_lookup_ifunc, elf_reloc, true); 1895 } 1896 #endif 1897