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 { 0, 0 } 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 #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 static int 740 link_elf_link_preload(linker_class_t cls, 741 const char* filename, linker_file_t *result) 742 { 743 Elf_Addr *ctors_addrp; 744 Elf_Size *ctors_sizep; 745 caddr_t modptr, baseptr, sizeptr, dynptr; 746 char *type; 747 elf_file_t ef; 748 linker_file_t lf; 749 int error; 750 vm_offset_t dp; 751 752 /* Look to see if we have the file preloaded */ 753 modptr = preload_search_by_name(filename); 754 if (modptr == NULL) 755 return (ENOENT); 756 757 type = (char *)preload_search_info(modptr, MODINFO_TYPE); 758 baseptr = preload_search_info(modptr, MODINFO_ADDR); 759 sizeptr = preload_search_info(modptr, MODINFO_SIZE); 760 dynptr = preload_search_info(modptr, 761 MODINFO_METADATA | MODINFOMD_DYNAMIC); 762 if (type == NULL || 763 (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) " module") != 0 && 764 strcmp(type, "elf module") != 0)) 765 return (EFTYPE); 766 if (baseptr == NULL || sizeptr == NULL || dynptr == NULL) 767 return (EINVAL); 768 769 lf = linker_make_file(filename, &link_elf_class); 770 if (lf == NULL) 771 return (ENOMEM); 772 773 ef = (elf_file_t) lf; 774 ef->preloaded = 1; 775 ef->modptr = modptr; 776 ef->address = *(caddr_t *)baseptr; 777 #ifdef SPARSE_MAPPING 778 ef->object = NULL; 779 #endif 780 dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr; 781 ef->dynamic = (Elf_Dyn *)dp; 782 lf->address = ef->address; 783 lf->size = *(size_t *)sizeptr; 784 785 ctors_addrp = (Elf_Addr *)preload_search_info(modptr, 786 MODINFO_METADATA | MODINFOMD_CTORS_ADDR); 787 ctors_sizep = (Elf_Size *)preload_search_info(modptr, 788 MODINFO_METADATA | MODINFOMD_CTORS_SIZE); 789 if (ctors_addrp != NULL && ctors_sizep != NULL) { 790 lf->ctors_addr = ef->address + *ctors_addrp; 791 lf->ctors_size = *ctors_sizep; 792 } 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_object_allocate(OBJT_PHYS, atop(mapsize)); 995 if (ef->object == NULL) { 996 error = ENOMEM; 997 goto out; 998 } 999 #ifdef __amd64__ 1000 mapbase = (caddr_t)KERNBASE; 1001 #else 1002 mapbase = (caddr_t)vm_map_min(kernel_map); 1003 #endif 1004 /* 1005 * Mapping protections are downgraded after relocation processing. 1006 */ 1007 error = vm_map_find(kernel_map, ef->object, 0, 1008 (vm_offset_t *)&mapbase, mapsize, 0, VMFS_OPTIMAL_SPACE, 1009 VM_PROT_ALL, VM_PROT_ALL, 0); 1010 if (error != 0) { 1011 vm_object_deallocate(ef->object); 1012 ef->object = NULL; 1013 goto out; 1014 } 1015 #else 1016 mapbase = malloc(mapsize, M_LINKER, M_EXEC | M_WAITOK); 1017 #endif 1018 ef->address = mapbase; 1019 1020 /* 1021 * Read the text and data sections and zero the bss. 1022 */ 1023 for (i = 0; i < nsegs; i++) { 1024 segbase = mapbase + segs[i]->p_vaddr - base_vaddr; 1025 1026 #ifdef SPARSE_MAPPING 1027 /* 1028 * Consecutive segments may have different mapping permissions, 1029 * so be strict and verify that their mappings do not overlap. 1030 */ 1031 if (((vm_offset_t)segbase & PAGE_MASK) != 0) { 1032 error = EINVAL; 1033 goto out; 1034 } 1035 1036 error = vm_map_wire(kernel_map, 1037 (vm_offset_t)segbase, 1038 (vm_offset_t)segbase + round_page(segs[i]->p_memsz), 1039 VM_MAP_WIRE_SYSTEM | VM_MAP_WIRE_NOHOLES); 1040 if (error != KERN_SUCCESS) { 1041 error = ENOMEM; 1042 goto out; 1043 } 1044 #endif 1045 1046 error = vn_rdwr(UIO_READ, nd.ni_vp, 1047 segbase, segs[i]->p_filesz, segs[i]->p_offset, 1048 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1049 &resid, td); 1050 if (error != 0) 1051 goto out; 1052 bzero(segbase + segs[i]->p_filesz, 1053 segs[i]->p_memsz - segs[i]->p_filesz); 1054 } 1055 1056 #ifdef GPROF 1057 /* Update profiling information with the new text segment. */ 1058 mtx_lock(&Giant); 1059 kmupetext((uintfptr_t)(mapbase + segs[0]->p_vaddr - base_vaddr + 1060 segs[0]->p_memsz)); 1061 mtx_unlock(&Giant); 1062 #endif 1063 1064 ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr); 1065 1066 lf->address = ef->address; 1067 lf->size = mapsize; 1068 1069 error = parse_dynamic(ef); 1070 if (error != 0) 1071 goto out; 1072 error = parse_dpcpu(ef); 1073 if (error != 0) 1074 goto out; 1075 #ifdef VIMAGE 1076 error = parse_vnet(ef); 1077 if (error != 0) 1078 goto out; 1079 #endif 1080 link_elf_reloc_local(lf); 1081 1082 VOP_UNLOCK(nd.ni_vp, 0); 1083 error = linker_load_dependencies(lf); 1084 vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY); 1085 if (error != 0) 1086 goto out; 1087 error = relocate_file(ef); 1088 if (error != 0) 1089 goto out; 1090 1091 #ifdef SPARSE_MAPPING 1092 /* 1093 * Downgrade permissions on text segment mappings now that relocation 1094 * processing is complete. Restrict permissions on read-only segments. 1095 */ 1096 for (i = 0; i < nsegs; i++) { 1097 vm_prot_t prot; 1098 1099 if (segs[i]->p_type != PT_LOAD) 1100 continue; 1101 1102 prot = VM_PROT_READ; 1103 if ((segs[i]->p_flags & PF_W) != 0) 1104 prot |= VM_PROT_WRITE; 1105 if ((segs[i]->p_flags & PF_X) != 0) 1106 prot |= VM_PROT_EXECUTE; 1107 segbase = mapbase + segs[i]->p_vaddr - base_vaddr; 1108 error = vm_map_protect(kernel_map, 1109 (vm_offset_t)segbase, 1110 (vm_offset_t)segbase + round_page(segs[i]->p_memsz), 1111 prot, FALSE); 1112 if (error != KERN_SUCCESS) { 1113 error = ENOMEM; 1114 goto out; 1115 } 1116 } 1117 #endif 1118 1119 /* 1120 * Try and load the symbol table if it's present. (you can 1121 * strip it!) 1122 */ 1123 nbytes = hdr->e_shnum * hdr->e_shentsize; 1124 if (nbytes == 0 || hdr->e_shoff == 0) 1125 goto nosyms; 1126 shdr = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO); 1127 error = vn_rdwr(UIO_READ, nd.ni_vp, 1128 (caddr_t)shdr, nbytes, hdr->e_shoff, 1129 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1130 &resid, td); 1131 if (error != 0) 1132 goto out; 1133 1134 /* Read section string table */ 1135 shstrindex = hdr->e_shstrndx; 1136 if (shstrindex != 0 && shdr[shstrindex].sh_type == SHT_STRTAB && 1137 shdr[shstrindex].sh_size != 0) { 1138 nbytes = shdr[shstrindex].sh_size; 1139 shstrs = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO); 1140 error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)shstrs, nbytes, 1141 shdr[shstrindex].sh_offset, UIO_SYSSPACE, IO_NODELOCKED, 1142 td->td_ucred, NOCRED, &resid, td); 1143 if (error) 1144 goto out; 1145 } 1146 1147 symtabindex = -1; 1148 symstrindex = -1; 1149 for (i = 0; i < hdr->e_shnum; i++) { 1150 if (shdr[i].sh_type == SHT_SYMTAB) { 1151 symtabindex = i; 1152 symstrindex = shdr[i].sh_link; 1153 } else if (shstrs != NULL && shdr[i].sh_name != 0 && 1154 strcmp(shstrs + shdr[i].sh_name, ".ctors") == 0) { 1155 /* Record relocated address and size of .ctors. */ 1156 lf->ctors_addr = mapbase + shdr[i].sh_addr - base_vaddr; 1157 lf->ctors_size = shdr[i].sh_size; 1158 } 1159 } 1160 if (symtabindex < 0 || symstrindex < 0) 1161 goto nosyms; 1162 1163 symcnt = shdr[symtabindex].sh_size; 1164 ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK); 1165 strcnt = shdr[symstrindex].sh_size; 1166 ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK); 1167 1168 error = vn_rdwr(UIO_READ, nd.ni_vp, 1169 ef->symbase, symcnt, shdr[symtabindex].sh_offset, 1170 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1171 &resid, td); 1172 if (error != 0) 1173 goto out; 1174 error = vn_rdwr(UIO_READ, nd.ni_vp, 1175 ef->strbase, strcnt, shdr[symstrindex].sh_offset, 1176 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1177 &resid, td); 1178 if (error != 0) 1179 goto out; 1180 1181 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym); 1182 ef->ddbsymtab = (const Elf_Sym *)ef->symbase; 1183 ef->ddbstrcnt = strcnt; 1184 ef->ddbstrtab = ef->strbase; 1185 1186 nosyms: 1187 error = link_elf_link_common_finish(lf); 1188 if (error != 0) 1189 goto out; 1190 1191 *result = lf; 1192 1193 out: 1194 VOP_UNLOCK(nd.ni_vp, 0); 1195 vn_close(nd.ni_vp, FREAD, td->td_ucred, td); 1196 if (error != 0 && lf != NULL) 1197 linker_file_unload(lf, LINKER_UNLOAD_FORCE); 1198 free(shdr, M_LINKER); 1199 free(firstpage, M_LINKER); 1200 free(shstrs, M_LINKER); 1201 1202 return (error); 1203 } 1204 1205 Elf_Addr 1206 elf_relocaddr(linker_file_t lf, Elf_Addr x) 1207 { 1208 elf_file_t ef; 1209 1210 KASSERT(lf->ops->cls == (kobj_class_t)&link_elf_class, 1211 ("elf_relocaddr: unexpected linker file %p", lf)); 1212 1213 ef = (elf_file_t)lf; 1214 if (x >= ef->pcpu_start && x < ef->pcpu_stop) 1215 return ((x - ef->pcpu_start) + ef->pcpu_base); 1216 #ifdef VIMAGE 1217 if (x >= ef->vnet_start && x < ef->vnet_stop) 1218 return ((x - ef->vnet_start) + ef->vnet_base); 1219 #endif 1220 return (x); 1221 } 1222 1223 1224 static void 1225 link_elf_unload_file(linker_file_t file) 1226 { 1227 elf_file_t ef = (elf_file_t) file; 1228 1229 if (ef->pcpu_base != 0) { 1230 dpcpu_free((void *)ef->pcpu_base, 1231 ef->pcpu_stop - ef->pcpu_start); 1232 elf_set_delete(&set_pcpu_list, ef->pcpu_start); 1233 } 1234 #ifdef VIMAGE 1235 if (ef->vnet_base != 0) { 1236 vnet_data_free((void *)ef->vnet_base, 1237 ef->vnet_stop - ef->vnet_start); 1238 elf_set_delete(&set_vnet_list, ef->vnet_start); 1239 } 1240 #endif 1241 #ifdef GDB 1242 if (ef->gdb.l_ld != NULL) { 1243 GDB_STATE(RT_DELETE); 1244 free((void *)(uintptr_t)ef->gdb.l_name, M_LINKER); 1245 link_elf_delete_gdb(&ef->gdb); 1246 GDB_STATE(RT_CONSISTENT); 1247 } 1248 #endif 1249 1250 /* Notify MD code that a module is being unloaded. */ 1251 elf_cpu_unload_file(file); 1252 1253 if (ef->preloaded) { 1254 link_elf_unload_preload(file); 1255 return; 1256 } 1257 1258 #ifdef SPARSE_MAPPING 1259 if (ef->object != NULL) { 1260 vm_map_remove(kernel_map, (vm_offset_t) ef->address, 1261 (vm_offset_t) ef->address 1262 + (ef->object->size << PAGE_SHIFT)); 1263 } 1264 #else 1265 free(ef->address, M_LINKER); 1266 #endif 1267 free(ef->symbase, M_LINKER); 1268 free(ef->strbase, M_LINKER); 1269 free(ef->ctftab, M_LINKER); 1270 free(ef->ctfoff, M_LINKER); 1271 free(ef->typoff, M_LINKER); 1272 } 1273 1274 static void 1275 link_elf_unload_preload(linker_file_t file) 1276 { 1277 if (file->pathname != NULL) 1278 preload_delete_name(file->pathname); 1279 } 1280 1281 static const char * 1282 symbol_name(elf_file_t ef, Elf_Size r_info) 1283 { 1284 const Elf_Sym *ref; 1285 1286 if (ELF_R_SYM(r_info)) { 1287 ref = ef->symtab + ELF_R_SYM(r_info); 1288 return (ef->strtab + ref->st_name); 1289 } 1290 return (NULL); 1291 } 1292 1293 static int 1294 symbol_type(elf_file_t ef, Elf_Size r_info) 1295 { 1296 const Elf_Sym *ref; 1297 1298 if (ELF_R_SYM(r_info)) { 1299 ref = ef->symtab + ELF_R_SYM(r_info); 1300 return (ELF_ST_TYPE(ref->st_info)); 1301 } 1302 return (STT_NOTYPE); 1303 } 1304 1305 static int 1306 relocate_file1(elf_file_t ef, elf_lookup_fn lookup, elf_reloc_fn reloc, 1307 bool ifuncs) 1308 { 1309 const Elf_Rel *rel; 1310 const Elf_Rela *rela; 1311 const char *symname; 1312 1313 #define APPLY_RELOCS(iter, tbl, tblsize, type) do { \ 1314 for ((iter) = (tbl); (iter) != NULL && \ 1315 (iter) < (tbl) + (tblsize) / sizeof(*(iter)); (iter)++) { \ 1316 if ((symbol_type(ef, (iter)->r_info) == \ 1317 STT_GNU_IFUNC || \ 1318 elf_is_ifunc_reloc((iter)->r_info)) != ifuncs) \ 1319 continue; \ 1320 if (reloc(&ef->lf, (Elf_Addr)ef->address, \ 1321 (iter), (type), lookup)) { \ 1322 symname = symbol_name(ef, (iter)->r_info); \ 1323 printf("link_elf: symbol %s undefined\n", \ 1324 symname); \ 1325 return (ENOENT); \ 1326 } \ 1327 } \ 1328 } while (0) 1329 1330 APPLY_RELOCS(rel, ef->rel, ef->relsize, ELF_RELOC_REL); 1331 APPLY_RELOCS(rela, ef->rela, ef->relasize, ELF_RELOC_RELA); 1332 APPLY_RELOCS(rel, ef->pltrel, ef->pltrelsize, ELF_RELOC_REL); 1333 APPLY_RELOCS(rela, ef->pltrela, ef->pltrelasize, ELF_RELOC_RELA); 1334 1335 #undef APPLY_RELOCS 1336 1337 return (0); 1338 } 1339 1340 static int 1341 relocate_file(elf_file_t ef) 1342 { 1343 int error; 1344 1345 error = relocate_file1(ef, elf_lookup, elf_reloc, false); 1346 if (error == 0) 1347 error = relocate_file1(ef, elf_lookup, elf_reloc, true); 1348 return (error); 1349 } 1350 1351 /* 1352 * Hash function for symbol table lookup. Don't even think about changing 1353 * this. It is specified by the System V ABI. 1354 */ 1355 static unsigned long 1356 elf_hash(const char *name) 1357 { 1358 const unsigned char *p = (const unsigned char *) name; 1359 unsigned long h = 0; 1360 unsigned long g; 1361 1362 while (*p != '\0') { 1363 h = (h << 4) + *p++; 1364 if ((g = h & 0xf0000000) != 0) 1365 h ^= g >> 24; 1366 h &= ~g; 1367 } 1368 return (h); 1369 } 1370 1371 static int 1372 link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym) 1373 { 1374 elf_file_t ef = (elf_file_t) lf; 1375 unsigned long symnum; 1376 const Elf_Sym* symp; 1377 const char *strp; 1378 unsigned long hash; 1379 int i; 1380 1381 /* If we don't have a hash, bail. */ 1382 if (ef->buckets == NULL || ef->nbuckets == 0) { 1383 printf("link_elf_lookup_symbol: missing symbol hash table\n"); 1384 return (ENOENT); 1385 } 1386 1387 /* First, search hashed global symbols */ 1388 hash = elf_hash(name); 1389 symnum = ef->buckets[hash % ef->nbuckets]; 1390 1391 while (symnum != STN_UNDEF) { 1392 if (symnum >= ef->nchains) { 1393 printf("%s: corrupt symbol table\n", __func__); 1394 return (ENOENT); 1395 } 1396 1397 symp = ef->symtab + symnum; 1398 if (symp->st_name == 0) { 1399 printf("%s: corrupt symbol table\n", __func__); 1400 return (ENOENT); 1401 } 1402 1403 strp = ef->strtab + symp->st_name; 1404 1405 if (strcmp(name, strp) == 0) { 1406 if (symp->st_shndx != SHN_UNDEF || 1407 (symp->st_value != 0 && 1408 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1409 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC))) { 1410 *sym = (c_linker_sym_t) symp; 1411 return (0); 1412 } 1413 return (ENOENT); 1414 } 1415 1416 symnum = ef->chains[symnum]; 1417 } 1418 1419 /* If we have not found it, look at the full table (if loaded) */ 1420 if (ef->symtab == ef->ddbsymtab) 1421 return (ENOENT); 1422 1423 /* Exhaustive search */ 1424 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1425 strp = ef->ddbstrtab + symp->st_name; 1426 if (strcmp(name, strp) == 0) { 1427 if (symp->st_shndx != SHN_UNDEF || 1428 (symp->st_value != 0 && 1429 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1430 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC))) { 1431 *sym = (c_linker_sym_t) symp; 1432 return (0); 1433 } 1434 return (ENOENT); 1435 } 1436 } 1437 1438 return (ENOENT); 1439 } 1440 1441 static int 1442 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, 1443 linker_symval_t *symval) 1444 { 1445 elf_file_t ef; 1446 const Elf_Sym *es; 1447 caddr_t val; 1448 1449 ef = (elf_file_t)lf; 1450 es = (const Elf_Sym *)sym; 1451 if (es >= ef->symtab && es < (ef->symtab + ef->nchains)) { 1452 symval->name = ef->strtab + es->st_name; 1453 val = (caddr_t)ef->address + es->st_value; 1454 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC) 1455 val = ((caddr_t (*)(void))val)(); 1456 symval->value = val; 1457 symval->size = es->st_size; 1458 return (0); 1459 } 1460 if (ef->symtab == ef->ddbsymtab) 1461 return (ENOENT); 1462 if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) { 1463 symval->name = ef->ddbstrtab + es->st_name; 1464 val = (caddr_t)ef->address + es->st_value; 1465 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC) 1466 val = ((caddr_t (*)(void))val)(); 1467 symval->value = val; 1468 symval->size = es->st_size; 1469 return (0); 1470 } 1471 return (ENOENT); 1472 } 1473 1474 static int 1475 link_elf_search_symbol(linker_file_t lf, caddr_t value, 1476 c_linker_sym_t *sym, long *diffp) 1477 { 1478 elf_file_t ef = (elf_file_t) lf; 1479 u_long off = (uintptr_t) (void *) value; 1480 u_long diff = off; 1481 u_long st_value; 1482 const Elf_Sym* es; 1483 const Elf_Sym* best = NULL; 1484 int i; 1485 1486 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) { 1487 if (es->st_name == 0) 1488 continue; 1489 st_value = es->st_value + (uintptr_t) (void *) ef->address; 1490 if (off >= st_value) { 1491 if (off - st_value < diff) { 1492 diff = off - st_value; 1493 best = es; 1494 if (diff == 0) 1495 break; 1496 } else if (off - st_value == diff) { 1497 best = es; 1498 } 1499 } 1500 } 1501 if (best == NULL) 1502 *diffp = off; 1503 else 1504 *diffp = diff; 1505 *sym = (c_linker_sym_t) best; 1506 1507 return (0); 1508 } 1509 1510 /* 1511 * Look up a linker set on an ELF system. 1512 */ 1513 static int 1514 link_elf_lookup_set(linker_file_t lf, const char *name, 1515 void ***startp, void ***stopp, int *countp) 1516 { 1517 c_linker_sym_t sym; 1518 linker_symval_t symval; 1519 char *setsym; 1520 void **start, **stop; 1521 int len, error = 0, count; 1522 1523 len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */ 1524 setsym = malloc(len, M_LINKER, M_WAITOK); 1525 1526 /* get address of first entry */ 1527 snprintf(setsym, len, "%s%s", "__start_set_", name); 1528 error = link_elf_lookup_symbol(lf, setsym, &sym); 1529 if (error != 0) 1530 goto out; 1531 link_elf_symbol_values(lf, sym, &symval); 1532 if (symval.value == 0) { 1533 error = ESRCH; 1534 goto out; 1535 } 1536 start = (void **)symval.value; 1537 1538 /* get address of last entry */ 1539 snprintf(setsym, len, "%s%s", "__stop_set_", name); 1540 error = link_elf_lookup_symbol(lf, setsym, &sym); 1541 if (error != 0) 1542 goto out; 1543 link_elf_symbol_values(lf, sym, &symval); 1544 if (symval.value == 0) { 1545 error = ESRCH; 1546 goto out; 1547 } 1548 stop = (void **)symval.value; 1549 1550 /* and the number of entries */ 1551 count = stop - start; 1552 1553 /* and copy out */ 1554 if (startp != NULL) 1555 *startp = start; 1556 if (stopp != NULL) 1557 *stopp = stop; 1558 if (countp != NULL) 1559 *countp = count; 1560 1561 out: 1562 free(setsym, M_LINKER); 1563 return (error); 1564 } 1565 1566 static int 1567 link_elf_each_function_name(linker_file_t file, 1568 int (*callback)(const char *, void *), void *opaque) 1569 { 1570 elf_file_t ef = (elf_file_t)file; 1571 const Elf_Sym *symp; 1572 int i, error; 1573 1574 /* Exhaustive search */ 1575 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1576 if (symp->st_value != 0 && 1577 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1578 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) { 1579 error = callback(ef->ddbstrtab + symp->st_name, opaque); 1580 if (error != 0) 1581 return (error); 1582 } 1583 } 1584 return (0); 1585 } 1586 1587 static int 1588 link_elf_each_function_nameval(linker_file_t file, 1589 linker_function_nameval_callback_t callback, void *opaque) 1590 { 1591 linker_symval_t symval; 1592 elf_file_t ef = (elf_file_t)file; 1593 const Elf_Sym* symp; 1594 int i, error; 1595 1596 /* Exhaustive search */ 1597 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1598 if (symp->st_value != 0 && 1599 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1600 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) { 1601 error = link_elf_symbol_values(file, 1602 (c_linker_sym_t) symp, &symval); 1603 if (error != 0) 1604 return (error); 1605 error = callback(file, i, &symval, opaque); 1606 if (error != 0) 1607 return (error); 1608 } 1609 } 1610 return (0); 1611 } 1612 1613 const Elf_Sym * 1614 elf_get_sym(linker_file_t lf, Elf_Size symidx) 1615 { 1616 elf_file_t ef = (elf_file_t)lf; 1617 1618 if (symidx >= ef->nchains) 1619 return (NULL); 1620 return (ef->symtab + symidx); 1621 } 1622 1623 const char * 1624 elf_get_symname(linker_file_t lf, Elf_Size symidx) 1625 { 1626 elf_file_t ef = (elf_file_t)lf; 1627 const Elf_Sym *sym; 1628 1629 if (symidx >= ef->nchains) 1630 return (NULL); 1631 sym = ef->symtab + symidx; 1632 return (ef->strtab + sym->st_name); 1633 } 1634 1635 /* 1636 * Symbol lookup function that can be used when the symbol index is known (ie 1637 * in relocations). It uses the symbol index instead of doing a fully fledged 1638 * hash table based lookup when such is valid. For example for local symbols. 1639 * This is not only more efficient, it's also more correct. It's not always 1640 * the case that the symbol can be found through the hash table. 1641 */ 1642 static int 1643 elf_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res) 1644 { 1645 elf_file_t ef = (elf_file_t)lf; 1646 const Elf_Sym *sym; 1647 const char *symbol; 1648 Elf_Addr addr, start, base; 1649 1650 /* Don't even try to lookup the symbol if the index is bogus. */ 1651 if (symidx >= ef->nchains) { 1652 *res = 0; 1653 return (EINVAL); 1654 } 1655 1656 sym = ef->symtab + symidx; 1657 1658 /* 1659 * Don't do a full lookup when the symbol is local. It may even 1660 * fail because it may not be found through the hash table. 1661 */ 1662 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) { 1663 /* Force lookup failure when we have an insanity. */ 1664 if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0) { 1665 *res = 0; 1666 return (EINVAL); 1667 } 1668 *res = ((Elf_Addr)ef->address + sym->st_value); 1669 return (0); 1670 } 1671 1672 /* 1673 * XXX we can avoid doing a hash table based lookup for global 1674 * symbols as well. This however is not always valid, so we'll 1675 * just do it the hard way for now. Performance tweaks can 1676 * always be added. 1677 */ 1678 1679 symbol = ef->strtab + sym->st_name; 1680 1681 /* Force a lookup failure if the symbol name is bogus. */ 1682 if (*symbol == 0) { 1683 *res = 0; 1684 return (EINVAL); 1685 } 1686 1687 addr = ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps)); 1688 if (addr == 0 && ELF_ST_BIND(sym->st_info) != STB_WEAK) { 1689 *res = 0; 1690 return (EINVAL); 1691 } 1692 1693 if (elf_set_find(&set_pcpu_list, addr, &start, &base)) 1694 addr = addr - start + base; 1695 #ifdef VIMAGE 1696 else if (elf_set_find(&set_vnet_list, addr, &start, &base)) 1697 addr = addr - start + base; 1698 #endif 1699 *res = addr; 1700 return (0); 1701 } 1702 1703 static void 1704 link_elf_reloc_local(linker_file_t lf) 1705 { 1706 const Elf_Rel *rellim; 1707 const Elf_Rel *rel; 1708 const Elf_Rela *relalim; 1709 const Elf_Rela *rela; 1710 elf_file_t ef = (elf_file_t)lf; 1711 1712 /* Perform relocations without addend if there are any: */ 1713 if ((rel = ef->rel) != NULL) { 1714 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize); 1715 while (rel < rellim) { 1716 elf_reloc_local(lf, (Elf_Addr)ef->address, rel, 1717 ELF_RELOC_REL, elf_lookup); 1718 rel++; 1719 } 1720 } 1721 1722 /* Perform relocations with addend if there are any: */ 1723 if ((rela = ef->rela) != NULL) { 1724 relalim = (const Elf_Rela *) 1725 ((const char *)ef->rela + ef->relasize); 1726 while (rela < relalim) { 1727 elf_reloc_local(lf, (Elf_Addr)ef->address, rela, 1728 ELF_RELOC_RELA, elf_lookup); 1729 rela++; 1730 } 1731 } 1732 } 1733 1734 static long 1735 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab) 1736 { 1737 elf_file_t ef = (elf_file_t)lf; 1738 1739 *symtab = ef->ddbsymtab; 1740 1741 if (*symtab == NULL) 1742 return (0); 1743 1744 return (ef->ddbsymcnt); 1745 } 1746 1747 static long 1748 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab) 1749 { 1750 elf_file_t ef = (elf_file_t)lf; 1751 1752 *strtab = ef->ddbstrtab; 1753 1754 if (*strtab == NULL) 1755 return (0); 1756 1757 return (ef->ddbstrcnt); 1758 } 1759 1760 #if defined(__i386__) || defined(__amd64__) || defined(__aarch64__) 1761 /* 1762 * Use this lookup routine when performing relocations early during boot. 1763 * The generic lookup routine depends on kobj, which is not initialized 1764 * at that point. 1765 */ 1766 static int 1767 elf_lookup_ifunc(linker_file_t lf, Elf_Size symidx, int deps __unused, 1768 Elf_Addr *res) 1769 { 1770 elf_file_t ef; 1771 const Elf_Sym *symp; 1772 caddr_t val; 1773 1774 ef = (elf_file_t)lf; 1775 symp = ef->symtab + symidx; 1776 if (ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC) { 1777 val = (caddr_t)ef->address + symp->st_value; 1778 *res = ((Elf_Addr (*)(void))val)(); 1779 return (0); 1780 } 1781 return (ENOENT); 1782 } 1783 1784 void 1785 link_elf_ireloc(caddr_t kmdp) 1786 { 1787 struct elf_file eff; 1788 elf_file_t ef; 1789 1790 ef = &eff; 1791 1792 bzero_early(ef, sizeof(*ef)); 1793 1794 ef->modptr = kmdp; 1795 ef->dynamic = (Elf_Dyn *)&_DYNAMIC; 1796 parse_dynamic(ef); 1797 ef->address = 0; 1798 link_elf_preload_parse_symbols(ef); 1799 relocate_file1(ef, elf_lookup_ifunc, elf_reloc, true); 1800 } 1801 #endif 1802