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 #include <sys/sysctl.h> 55 56 #include <machine/elf.h> 57 58 #include <net/vnet.h> 59 60 #include <security/mac/mac_framework.h> 61 62 #include <vm/vm.h> 63 #include <vm/vm_param.h> 64 #ifdef SPARSE_MAPPING 65 #include <vm/vm_object.h> 66 #include <vm/vm_kern.h> 67 #include <vm/vm_extern.h> 68 #endif 69 #include <vm/pmap.h> 70 #include <vm/vm_map.h> 71 72 #include <sys/link_elf.h> 73 74 #include "linker_if.h" 75 76 #define MAXSEGS 4 77 78 typedef struct elf_file { 79 struct linker_file lf; /* Common fields */ 80 int preloaded; /* Was file pre-loaded */ 81 caddr_t address; /* Relocation address */ 82 #ifdef SPARSE_MAPPING 83 vm_object_t object; /* VM object to hold file pages */ 84 #endif 85 Elf_Dyn *dynamic; /* Symbol table etc. */ 86 Elf_Hashelt nbuckets; /* DT_HASH info */ 87 Elf_Hashelt nchains; 88 const Elf_Hashelt *buckets; 89 const Elf_Hashelt *chains; 90 caddr_t hash; 91 caddr_t strtab; /* DT_STRTAB */ 92 int strsz; /* DT_STRSZ */ 93 const Elf_Sym *symtab; /* DT_SYMTAB */ 94 Elf_Addr *got; /* DT_PLTGOT */ 95 const Elf_Rel *pltrel; /* DT_JMPREL */ 96 int pltrelsize; /* DT_PLTRELSZ */ 97 const Elf_Rela *pltrela; /* DT_JMPREL */ 98 int pltrelasize; /* DT_PLTRELSZ */ 99 const Elf_Rel *rel; /* DT_REL */ 100 int relsize; /* DT_RELSZ */ 101 const Elf_Rela *rela; /* DT_RELA */ 102 int relasize; /* DT_RELASZ */ 103 caddr_t modptr; 104 const Elf_Sym *ddbsymtab; /* The symbol table we are using */ 105 long ddbsymcnt; /* Number of symbols */ 106 caddr_t ddbstrtab; /* String table */ 107 long ddbstrcnt; /* number of bytes in string table */ 108 caddr_t symbase; /* malloc'ed symbold base */ 109 caddr_t strbase; /* malloc'ed string base */ 110 caddr_t ctftab; /* CTF table */ 111 long ctfcnt; /* number of bytes in CTF table */ 112 caddr_t ctfoff; /* CTF offset table */ 113 caddr_t typoff; /* Type offset table */ 114 long typlen; /* Number of type entries. */ 115 Elf_Addr pcpu_start; /* Pre-relocation pcpu set start. */ 116 Elf_Addr pcpu_stop; /* Pre-relocation pcpu set stop. */ 117 Elf_Addr pcpu_base; /* Relocated pcpu set address. */ 118 #ifdef VIMAGE 119 Elf_Addr vnet_start; /* Pre-relocation vnet set start. */ 120 Elf_Addr vnet_stop; /* Pre-relocation vnet set stop. */ 121 Elf_Addr vnet_base; /* Relocated vnet set address. */ 122 #endif 123 #ifdef GDB 124 struct link_map gdb; /* hooks for gdb */ 125 #endif 126 } *elf_file_t; 127 128 struct elf_set { 129 Elf_Addr es_start; 130 Elf_Addr es_stop; 131 Elf_Addr es_base; 132 TAILQ_ENTRY(elf_set) es_link; 133 }; 134 135 TAILQ_HEAD(elf_set_head, elf_set); 136 137 #include <kern/kern_ctf.c> 138 139 static int link_elf_link_common_finish(linker_file_t); 140 static int link_elf_link_preload(linker_class_t cls, 141 const char *, linker_file_t *); 142 static int link_elf_link_preload_finish(linker_file_t); 143 static int link_elf_load_file(linker_class_t, const char *, 144 linker_file_t *); 145 static int link_elf_lookup_symbol(linker_file_t, const char *, 146 c_linker_sym_t *); 147 static int link_elf_symbol_values(linker_file_t, c_linker_sym_t, 148 linker_symval_t *); 149 static int link_elf_search_symbol(linker_file_t, caddr_t, 150 c_linker_sym_t *, long *); 151 152 static void link_elf_unload_file(linker_file_t); 153 static void link_elf_unload_preload(linker_file_t); 154 static int link_elf_lookup_set(linker_file_t, const char *, 155 void ***, void ***, int *); 156 static int link_elf_each_function_name(linker_file_t, 157 int (*)(const char *, void *), void *); 158 static int link_elf_each_function_nameval(linker_file_t, 159 linker_function_nameval_callback_t, void *); 160 static void link_elf_reloc_local(linker_file_t); 161 static long link_elf_symtab_get(linker_file_t, const Elf_Sym **); 162 static long link_elf_strtab_get(linker_file_t, caddr_t *); 163 static int elf_lookup(linker_file_t, Elf_Size, int, Elf_Addr *); 164 165 static kobj_method_t link_elf_methods[] = { 166 KOBJMETHOD(linker_lookup_symbol, link_elf_lookup_symbol), 167 KOBJMETHOD(linker_symbol_values, link_elf_symbol_values), 168 KOBJMETHOD(linker_search_symbol, link_elf_search_symbol), 169 KOBJMETHOD(linker_unload, link_elf_unload_file), 170 KOBJMETHOD(linker_load_file, link_elf_load_file), 171 KOBJMETHOD(linker_link_preload, link_elf_link_preload), 172 KOBJMETHOD(linker_link_preload_finish, link_elf_link_preload_finish), 173 KOBJMETHOD(linker_lookup_set, link_elf_lookup_set), 174 KOBJMETHOD(linker_each_function_name, link_elf_each_function_name), 175 KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval), 176 KOBJMETHOD(linker_ctf_get, link_elf_ctf_get), 177 KOBJMETHOD(linker_symtab_get, link_elf_symtab_get), 178 KOBJMETHOD(linker_strtab_get, link_elf_strtab_get), 179 KOBJMETHOD_END 180 }; 181 182 static struct linker_class link_elf_class = { 183 #if ELF_TARG_CLASS == ELFCLASS32 184 "elf32", 185 #else 186 "elf64", 187 #endif 188 link_elf_methods, sizeof(struct elf_file) 189 }; 190 191 typedef int (*elf_reloc_fn)(linker_file_t lf, Elf_Addr relocbase, 192 const void *data, int type, elf_lookup_fn lookup); 193 194 static int parse_dynamic(elf_file_t); 195 static int relocate_file(elf_file_t); 196 static int relocate_file1(elf_file_t ef, elf_lookup_fn lookup, 197 elf_reloc_fn reloc, bool ifuncs); 198 static int link_elf_preload_parse_symbols(elf_file_t); 199 200 static struct elf_set_head set_pcpu_list; 201 #ifdef VIMAGE 202 static struct elf_set_head set_vnet_list; 203 #endif 204 205 static void 206 elf_set_add(struct elf_set_head *list, Elf_Addr start, Elf_Addr stop, Elf_Addr base) 207 { 208 struct elf_set *set, *iter; 209 210 set = malloc(sizeof(*set), M_LINKER, M_WAITOK); 211 set->es_start = start; 212 set->es_stop = stop; 213 set->es_base = base; 214 215 TAILQ_FOREACH(iter, list, es_link) { 216 217 KASSERT((set->es_start < iter->es_start && set->es_stop < iter->es_stop) || 218 (set->es_start > iter->es_start && set->es_stop > iter->es_stop), 219 ("linker sets intersection: to insert: 0x%jx-0x%jx; inserted: 0x%jx-0x%jx", 220 (uintmax_t)set->es_start, (uintmax_t)set->es_stop, 221 (uintmax_t)iter->es_start, (uintmax_t)iter->es_stop)); 222 223 if (iter->es_start > set->es_start) { 224 TAILQ_INSERT_BEFORE(iter, set, es_link); 225 break; 226 } 227 } 228 229 if (iter == NULL) 230 TAILQ_INSERT_TAIL(list, set, es_link); 231 } 232 233 static int 234 elf_set_find(struct elf_set_head *list, Elf_Addr addr, Elf_Addr *start, Elf_Addr *base) 235 { 236 struct elf_set *set; 237 238 TAILQ_FOREACH(set, list, es_link) { 239 if (addr < set->es_start) 240 return (0); 241 if (addr < set->es_stop) { 242 *start = set->es_start; 243 *base = set->es_base; 244 return (1); 245 } 246 } 247 248 return (0); 249 } 250 251 static void 252 elf_set_delete(struct elf_set_head *list, Elf_Addr start) 253 { 254 struct elf_set *set; 255 256 TAILQ_FOREACH(set, list, es_link) { 257 if (start < set->es_start) 258 break; 259 if (start == set->es_start) { 260 TAILQ_REMOVE(list, set, es_link); 261 free(set, M_LINKER); 262 return; 263 } 264 } 265 KASSERT(0, ("deleting unknown linker set (start = 0x%jx)", 266 (uintmax_t)start)); 267 } 268 269 #ifdef GDB 270 static void r_debug_state(struct r_debug *, struct link_map *); 271 272 /* 273 * A list of loaded modules for GDB to use for loading symbols. 274 */ 275 struct r_debug r_debug; 276 277 #define GDB_STATE(s) do { \ 278 r_debug.r_state = s; r_debug_state(NULL, NULL); \ 279 } while (0) 280 281 /* 282 * Function for the debugger to set a breakpoint on to gain control. 283 */ 284 static void 285 r_debug_state(struct r_debug *dummy_one __unused, 286 struct link_map *dummy_two __unused) 287 { 288 } 289 290 static void 291 link_elf_add_gdb(struct link_map *l) 292 { 293 struct link_map *prev; 294 295 l->l_next = NULL; 296 297 if (r_debug.r_map == NULL) { 298 /* Add first. */ 299 l->l_prev = NULL; 300 r_debug.r_map = l; 301 } else { 302 /* Append to list. */ 303 for (prev = r_debug.r_map; 304 prev->l_next != NULL; 305 prev = prev->l_next) 306 ; 307 l->l_prev = prev; 308 prev->l_next = l; 309 } 310 } 311 312 static void 313 link_elf_delete_gdb(struct link_map *l) 314 { 315 if (l->l_prev == NULL) { 316 /* Remove first. */ 317 if ((r_debug.r_map = l->l_next) != NULL) 318 l->l_next->l_prev = NULL; 319 } else { 320 /* Remove any but first. */ 321 if ((l->l_prev->l_next = l->l_next) != NULL) 322 l->l_next->l_prev = l->l_prev; 323 } 324 } 325 #endif /* GDB */ 326 327 /* 328 * The kernel symbol table starts here. 329 */ 330 extern struct _dynamic _DYNAMIC; 331 332 static void 333 link_elf_error(const char *filename, const char *s) 334 { 335 if (filename == NULL) 336 printf("kldload: %s\n", s); 337 else 338 printf("kldload: %s: %s\n", filename, s); 339 } 340 341 static void 342 link_elf_invoke_ctors(caddr_t addr, size_t size) 343 { 344 void (**ctor)(void); 345 size_t i, cnt; 346 347 if (addr == NULL || size == 0) 348 return; 349 cnt = size / sizeof(*ctor); 350 ctor = (void *)addr; 351 for (i = 0; i < cnt; i++) { 352 if (ctor[i] != NULL) 353 (*ctor[i])(); 354 } 355 } 356 357 /* 358 * Actions performed after linking/loading both the preloaded kernel and any 359 * modules; whether preloaded or dynamicly loaded. 360 */ 361 static int 362 link_elf_link_common_finish(linker_file_t lf) 363 { 364 #ifdef GDB 365 elf_file_t ef = (elf_file_t)lf; 366 char *newfilename; 367 #endif 368 int error; 369 370 /* Notify MD code that a module is being loaded. */ 371 error = elf_cpu_load_file(lf); 372 if (error != 0) 373 return (error); 374 375 #ifdef GDB 376 GDB_STATE(RT_ADD); 377 ef->gdb.l_addr = lf->address; 378 newfilename = malloc(strlen(lf->filename) + 1, M_LINKER, M_WAITOK); 379 strcpy(newfilename, lf->filename); 380 ef->gdb.l_name = newfilename; 381 ef->gdb.l_ld = ef->dynamic; 382 link_elf_add_gdb(&ef->gdb); 383 GDB_STATE(RT_CONSISTENT); 384 #endif 385 386 /* Invoke .ctors */ 387 link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size); 388 return (0); 389 } 390 391 #ifdef RELOCATABLE_KERNEL 392 extern vm_offset_t __startkernel, __endkernel; 393 #endif 394 395 static unsigned long kern_relbase = KERNBASE; 396 397 SYSCTL_ULONG(_kern, OID_AUTO, base_address, CTLFLAG_RD, 398 SYSCTL_NULL_ULONG_PTR, KERNBASE, "Kernel base address"); 399 SYSCTL_ULONG(_kern, OID_AUTO, relbase_address, CTLFLAG_RD, 400 &kern_relbase, 0, "Kernel relocated base address"); 401 402 static void 403 link_elf_init(void* arg) 404 { 405 Elf_Dyn *dp; 406 Elf_Addr *ctors_addrp; 407 Elf_Size *ctors_sizep; 408 caddr_t modptr, baseptr, sizeptr; 409 elf_file_t ef; 410 const char *modname; 411 412 linker_add_class(&link_elf_class); 413 414 dp = (Elf_Dyn *)&_DYNAMIC; 415 modname = NULL; 416 modptr = preload_search_by_type("elf" __XSTRING(__ELF_WORD_SIZE) " kernel"); 417 if (modptr == NULL) 418 modptr = preload_search_by_type("elf kernel"); 419 modname = (char *)preload_search_info(modptr, MODINFO_NAME); 420 if (modname == NULL) 421 modname = "kernel"; 422 linker_kernel_file = linker_make_file(modname, &link_elf_class); 423 if (linker_kernel_file == NULL) 424 panic("%s: Can't create linker structures for kernel", 425 __func__); 426 427 ef = (elf_file_t) linker_kernel_file; 428 ef->preloaded = 1; 429 #ifdef RELOCATABLE_KERNEL 430 ef->address = (caddr_t) (__startkernel - KERNBASE); 431 #else 432 ef->address = 0; 433 #endif 434 #ifdef SPARSE_MAPPING 435 ef->object = NULL; 436 #endif 437 ef->dynamic = dp; 438 439 if (dp != NULL) 440 parse_dynamic(ef); 441 #ifdef RELOCATABLE_KERNEL 442 linker_kernel_file->address = (caddr_t)__startkernel; 443 linker_kernel_file->size = (intptr_t)(__endkernel - __startkernel); 444 kern_relbase = (unsigned long)__startkernel; 445 #else 446 linker_kernel_file->address += KERNBASE; 447 linker_kernel_file->size = -(intptr_t)linker_kernel_file->address; 448 #endif 449 450 if (modptr != NULL) { 451 ef->modptr = modptr; 452 baseptr = preload_search_info(modptr, MODINFO_ADDR); 453 if (baseptr != NULL) 454 linker_kernel_file->address = *(caddr_t *)baseptr; 455 sizeptr = preload_search_info(modptr, MODINFO_SIZE); 456 if (sizeptr != NULL) 457 linker_kernel_file->size = *(size_t *)sizeptr; 458 ctors_addrp = (Elf_Addr *)preload_search_info(modptr, 459 MODINFO_METADATA | MODINFOMD_CTORS_ADDR); 460 ctors_sizep = (Elf_Size *)preload_search_info(modptr, 461 MODINFO_METADATA | MODINFOMD_CTORS_SIZE); 462 if (ctors_addrp != NULL && ctors_sizep != NULL) { 463 linker_kernel_file->ctors_addr = ef->address + 464 *ctors_addrp; 465 linker_kernel_file->ctors_size = *ctors_sizep; 466 } 467 } 468 (void)link_elf_preload_parse_symbols(ef); 469 470 #ifdef GDB 471 r_debug.r_map = NULL; 472 r_debug.r_brk = r_debug_state; 473 r_debug.r_state = RT_CONSISTENT; 474 #endif 475 476 (void)link_elf_link_common_finish(linker_kernel_file); 477 linker_kernel_file->flags |= LINKER_FILE_LINKED; 478 TAILQ_INIT(&set_pcpu_list); 479 #ifdef VIMAGE 480 TAILQ_INIT(&set_vnet_list); 481 #endif 482 } 483 484 SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_THIRD, link_elf_init, NULL); 485 486 static int 487 link_elf_preload_parse_symbols(elf_file_t ef) 488 { 489 caddr_t pointer; 490 caddr_t ssym, esym, base; 491 caddr_t strtab; 492 int strcnt; 493 Elf_Sym *symtab; 494 int symcnt; 495 496 if (ef->modptr == NULL) 497 return (0); 498 pointer = preload_search_info(ef->modptr, 499 MODINFO_METADATA | MODINFOMD_SSYM); 500 if (pointer == NULL) 501 return (0); 502 ssym = *(caddr_t *)pointer; 503 pointer = preload_search_info(ef->modptr, 504 MODINFO_METADATA | MODINFOMD_ESYM); 505 if (pointer == NULL) 506 return (0); 507 esym = *(caddr_t *)pointer; 508 509 base = ssym; 510 511 symcnt = *(long *)base; 512 base += sizeof(long); 513 symtab = (Elf_Sym *)base; 514 base += roundup(symcnt, sizeof(long)); 515 516 if (base > esym || base < ssym) { 517 printf("Symbols are corrupt!\n"); 518 return (EINVAL); 519 } 520 521 strcnt = *(long *)base; 522 base += sizeof(long); 523 strtab = base; 524 base += roundup(strcnt, sizeof(long)); 525 526 if (base > esym || base < ssym) { 527 printf("Symbols are corrupt!\n"); 528 return (EINVAL); 529 } 530 531 ef->ddbsymtab = symtab; 532 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym); 533 ef->ddbstrtab = strtab; 534 ef->ddbstrcnt = strcnt; 535 536 return (0); 537 } 538 539 static int 540 parse_dynamic(elf_file_t ef) 541 { 542 Elf_Dyn *dp; 543 int plttype = DT_REL; 544 545 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) { 546 switch (dp->d_tag) { 547 case DT_HASH: 548 { 549 /* From src/libexec/rtld-elf/rtld.c */ 550 const Elf_Hashelt *hashtab = (const Elf_Hashelt *) 551 (ef->address + dp->d_un.d_ptr); 552 ef->nbuckets = hashtab[0]; 553 ef->nchains = hashtab[1]; 554 ef->buckets = hashtab + 2; 555 ef->chains = ef->buckets + ef->nbuckets; 556 break; 557 } 558 case DT_STRTAB: 559 ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr); 560 break; 561 case DT_STRSZ: 562 ef->strsz = dp->d_un.d_val; 563 break; 564 case DT_SYMTAB: 565 ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr); 566 break; 567 case DT_SYMENT: 568 if (dp->d_un.d_val != sizeof(Elf_Sym)) 569 return (ENOEXEC); 570 break; 571 case DT_PLTGOT: 572 ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr); 573 break; 574 case DT_REL: 575 ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr); 576 break; 577 case DT_RELSZ: 578 ef->relsize = dp->d_un.d_val; 579 break; 580 case DT_RELENT: 581 if (dp->d_un.d_val != sizeof(Elf_Rel)) 582 return (ENOEXEC); 583 break; 584 case DT_JMPREL: 585 ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr); 586 break; 587 case DT_PLTRELSZ: 588 ef->pltrelsize = dp->d_un.d_val; 589 break; 590 case DT_RELA: 591 ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr); 592 break; 593 case DT_RELASZ: 594 ef->relasize = dp->d_un.d_val; 595 break; 596 case DT_RELAENT: 597 if (dp->d_un.d_val != sizeof(Elf_Rela)) 598 return (ENOEXEC); 599 break; 600 case DT_PLTREL: 601 plttype = dp->d_un.d_val; 602 if (plttype != DT_REL && plttype != DT_RELA) 603 return (ENOEXEC); 604 break; 605 #ifdef GDB 606 case DT_DEBUG: 607 dp->d_un.d_ptr = (Elf_Addr)&r_debug; 608 break; 609 #endif 610 } 611 } 612 613 if (plttype == DT_RELA) { 614 ef->pltrela = (const Elf_Rela *)ef->pltrel; 615 ef->pltrel = NULL; 616 ef->pltrelasize = ef->pltrelsize; 617 ef->pltrelsize = 0; 618 } 619 620 ef->ddbsymtab = ef->symtab; 621 ef->ddbsymcnt = ef->nchains; 622 ef->ddbstrtab = ef->strtab; 623 ef->ddbstrcnt = ef->strsz; 624 625 return elf_cpu_parse_dynamic(ef->address, ef->dynamic); 626 } 627 628 #define LS_PADDING 0x90909090 629 static int 630 parse_dpcpu(elf_file_t ef) 631 { 632 int error, size; 633 #if defined(__i386__) 634 uint32_t pad; 635 #endif 636 637 ef->pcpu_start = 0; 638 ef->pcpu_stop = 0; 639 error = link_elf_lookup_set(&ef->lf, "pcpu", (void ***)&ef->pcpu_start, 640 (void ***)&ef->pcpu_stop, NULL); 641 /* Error just means there is no pcpu set to relocate. */ 642 if (error != 0) 643 return (0); 644 size = (uintptr_t)ef->pcpu_stop - (uintptr_t)ef->pcpu_start; 645 /* Empty set? */ 646 if (size < 1) 647 return (0); 648 #if defined(__i386__) 649 /* In case we do find __start/stop_set_ symbols double-check. */ 650 if (size < 4) { 651 uprintf("Kernel module '%s' must be recompiled with " 652 "linker script\n", ef->lf.pathname); 653 return (ENOEXEC); 654 } 655 656 /* Padding from linker-script correct? */ 657 pad = *(uint32_t *)((uintptr_t)ef->pcpu_stop - sizeof(pad)); 658 if (pad != LS_PADDING) { 659 uprintf("Kernel module '%s' must be recompiled with " 660 "linker script, invalid padding %#04x (%#04x)\n", 661 ef->lf.pathname, pad, LS_PADDING); 662 return (ENOEXEC); 663 } 664 /* If we only have valid padding, nothing to do. */ 665 if (size == 4) 666 return (0); 667 #endif 668 /* 669 * Allocate space in the primary pcpu area. Copy in our 670 * initialization from the data section and then initialize 671 * all per-cpu storage from that. 672 */ 673 ef->pcpu_base = (Elf_Addr)(uintptr_t)dpcpu_alloc(size); 674 if (ef->pcpu_base == 0) { 675 printf("%s: pcpu module space is out of space; " 676 "cannot allocate %d for %s\n", 677 __func__, size, ef->lf.pathname); 678 return (ENOSPC); 679 } 680 memcpy((void *)ef->pcpu_base, (void *)ef->pcpu_start, size); 681 dpcpu_copy((void *)ef->pcpu_base, size); 682 elf_set_add(&set_pcpu_list, ef->pcpu_start, ef->pcpu_stop, 683 ef->pcpu_base); 684 685 return (0); 686 } 687 688 #ifdef VIMAGE 689 static int 690 parse_vnet(elf_file_t ef) 691 { 692 int error, size; 693 #if defined(__i386__) 694 uint32_t pad; 695 #endif 696 697 ef->vnet_start = 0; 698 ef->vnet_stop = 0; 699 error = link_elf_lookup_set(&ef->lf, "vnet", (void ***)&ef->vnet_start, 700 (void ***)&ef->vnet_stop, NULL); 701 /* Error just means there is no vnet data set to relocate. */ 702 if (error != 0) 703 return (0); 704 size = (uintptr_t)ef->vnet_stop - (uintptr_t)ef->vnet_start; 705 /* Empty set? */ 706 if (size < 1) 707 return (0); 708 #if defined(__i386__) 709 /* In case we do find __start/stop_set_ symbols double-check. */ 710 if (size < 4) { 711 uprintf("Kernel module '%s' must be recompiled with " 712 "linker script\n", ef->lf.pathname); 713 return (ENOEXEC); 714 } 715 716 /* Padding from linker-script correct? */ 717 pad = *(uint32_t *)((uintptr_t)ef->vnet_stop - sizeof(pad)); 718 if (pad != LS_PADDING) { 719 uprintf("Kernel module '%s' must be recompiled with " 720 "linker script, invalid padding %#04x (%#04x)\n", 721 ef->lf.pathname, pad, LS_PADDING); 722 return (ENOEXEC); 723 } 724 /* If we only have valid padding, nothing to do. */ 725 if (size == 4) 726 return (0); 727 #endif 728 /* 729 * Allocate space in the primary vnet area. Copy in our 730 * initialization from the data section and then initialize 731 * all per-vnet storage from that. 732 */ 733 ef->vnet_base = (Elf_Addr)(uintptr_t)vnet_data_alloc(size); 734 if (ef->vnet_base == 0) { 735 printf("%s: vnet module space is out of space; " 736 "cannot allocate %d for %s\n", 737 __func__, size, ef->lf.pathname); 738 return (ENOSPC); 739 } 740 memcpy((void *)ef->vnet_base, (void *)ef->vnet_start, size); 741 vnet_data_copy((void *)ef->vnet_base, size); 742 elf_set_add(&set_vnet_list, ef->vnet_start, ef->vnet_stop, 743 ef->vnet_base); 744 745 return (0); 746 } 747 #endif 748 #undef LS_PADDING 749 750 /* 751 * Apply the specified protection to the loadable segments of a preloaded linker 752 * file. 753 */ 754 static int 755 preload_protect(elf_file_t ef, vm_prot_t prot) 756 { 757 #ifdef __amd64__ 758 Elf_Ehdr *hdr; 759 Elf_Phdr *phdr, *phlimit; 760 vm_prot_t nprot; 761 int error; 762 763 error = 0; 764 hdr = (Elf_Ehdr *)ef->address; 765 phdr = (Elf_Phdr *)(ef->address + hdr->e_phoff); 766 phlimit = phdr + hdr->e_phnum; 767 for (; phdr < phlimit; phdr++) { 768 if (phdr->p_type != PT_LOAD) 769 continue; 770 771 nprot = prot | VM_PROT_READ; 772 if ((phdr->p_flags & PF_W) != 0) 773 nprot |= VM_PROT_WRITE; 774 if ((phdr->p_flags & PF_X) != 0) 775 nprot |= VM_PROT_EXECUTE; 776 error = pmap_change_prot((vm_offset_t)ef->address + 777 phdr->p_vaddr, round_page(phdr->p_memsz), nprot); 778 if (error != 0) 779 break; 780 } 781 return (error); 782 #else 783 return (0); 784 #endif 785 } 786 787 #ifdef __arm__ 788 /* 789 * Locate the ARM exception/unwind table info for DDB and stack(9) use by 790 * searching for the section header that describes it. There may be no unwind 791 * info, for example in a module containing only data. 792 */ 793 static void 794 link_elf_locate_exidx(linker_file_t lf, Elf_Shdr *shdr, int nhdr) 795 { 796 int i; 797 798 for (i = 0; i < nhdr; i++) { 799 if (shdr[i].sh_type == SHT_ARM_EXIDX) { 800 lf->exidx_addr = shdr[i].sh_addr + lf->address; 801 lf->exidx_size = shdr[i].sh_size; 802 break; 803 } 804 } 805 } 806 807 /* 808 * Locate the section headers metadata in a preloaded module, then use it to 809 * locate the exception/unwind table in the module. The size of the metadata 810 * block is stored in a uint32 word immediately before the data itself, and a 811 * comment in preload_search_info() says it is safe to rely on that. 812 */ 813 static void 814 link_elf_locate_exidx_preload(struct linker_file *lf, caddr_t modptr) 815 { 816 uint32_t *modinfo; 817 Elf_Shdr *shdr; 818 uint32_t nhdr; 819 820 modinfo = (uint32_t *)preload_search_info(modptr, 821 MODINFO_METADATA | MODINFOMD_SHDR); 822 if (modinfo != NULL) { 823 shdr = (Elf_Shdr *)modinfo; 824 nhdr = modinfo[-1] / sizeof(Elf_Shdr); 825 link_elf_locate_exidx(lf, shdr, nhdr); 826 } 827 } 828 829 #endif /* __arm__ */ 830 831 static int 832 link_elf_link_preload(linker_class_t cls, const char *filename, 833 linker_file_t *result) 834 { 835 Elf_Addr *ctors_addrp; 836 Elf_Size *ctors_sizep; 837 caddr_t modptr, baseptr, sizeptr, dynptr; 838 char *type; 839 elf_file_t ef; 840 linker_file_t lf; 841 int error; 842 vm_offset_t dp; 843 844 /* Look to see if we have the file preloaded */ 845 modptr = preload_search_by_name(filename); 846 if (modptr == NULL) 847 return (ENOENT); 848 849 type = (char *)preload_search_info(modptr, MODINFO_TYPE); 850 baseptr = preload_search_info(modptr, MODINFO_ADDR); 851 sizeptr = preload_search_info(modptr, MODINFO_SIZE); 852 dynptr = preload_search_info(modptr, 853 MODINFO_METADATA | MODINFOMD_DYNAMIC); 854 if (type == NULL || 855 (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) " module") != 0 && 856 strcmp(type, "elf module") != 0)) 857 return (EFTYPE); 858 if (baseptr == NULL || sizeptr == NULL || dynptr == NULL) 859 return (EINVAL); 860 861 lf = linker_make_file(filename, &link_elf_class); 862 if (lf == NULL) 863 return (ENOMEM); 864 865 ef = (elf_file_t) lf; 866 ef->preloaded = 1; 867 ef->modptr = modptr; 868 ef->address = *(caddr_t *)baseptr; 869 #ifdef SPARSE_MAPPING 870 ef->object = NULL; 871 #endif 872 dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr; 873 ef->dynamic = (Elf_Dyn *)dp; 874 lf->address = ef->address; 875 lf->size = *(size_t *)sizeptr; 876 877 ctors_addrp = (Elf_Addr *)preload_search_info(modptr, 878 MODINFO_METADATA | MODINFOMD_CTORS_ADDR); 879 ctors_sizep = (Elf_Size *)preload_search_info(modptr, 880 MODINFO_METADATA | MODINFOMD_CTORS_SIZE); 881 if (ctors_addrp != NULL && ctors_sizep != NULL) { 882 lf->ctors_addr = ef->address + *ctors_addrp; 883 lf->ctors_size = *ctors_sizep; 884 } 885 886 #ifdef __arm__ 887 link_elf_locate_exidx_preload(lf, modptr); 888 #endif 889 890 error = parse_dynamic(ef); 891 if (error == 0) 892 error = parse_dpcpu(ef); 893 #ifdef VIMAGE 894 if (error == 0) 895 error = parse_vnet(ef); 896 #endif 897 if (error == 0) 898 error = preload_protect(ef, VM_PROT_ALL); 899 if (error != 0) { 900 linker_file_unload(lf, LINKER_UNLOAD_FORCE); 901 return (error); 902 } 903 link_elf_reloc_local(lf); 904 *result = lf; 905 return (0); 906 } 907 908 static int 909 link_elf_link_preload_finish(linker_file_t lf) 910 { 911 elf_file_t ef; 912 int error; 913 914 ef = (elf_file_t) lf; 915 error = relocate_file(ef); 916 if (error == 0) 917 error = preload_protect(ef, VM_PROT_NONE); 918 if (error != 0) 919 return (error); 920 (void)link_elf_preload_parse_symbols(ef); 921 922 return (link_elf_link_common_finish(lf)); 923 } 924 925 static int 926 link_elf_load_file(linker_class_t cls, const char* filename, 927 linker_file_t* result) 928 { 929 struct nameidata nd; 930 struct thread* td = curthread; /* XXX */ 931 Elf_Ehdr *hdr; 932 caddr_t firstpage, segbase; 933 int nbytes, i; 934 Elf_Phdr *phdr; 935 Elf_Phdr *phlimit; 936 Elf_Phdr *segs[MAXSEGS]; 937 int nsegs; 938 Elf_Phdr *phdyn; 939 caddr_t mapbase; 940 size_t mapsize; 941 Elf_Addr base_vaddr; 942 Elf_Addr base_vlimit; 943 int error = 0; 944 ssize_t resid; 945 int flags; 946 elf_file_t ef; 947 linker_file_t lf; 948 Elf_Shdr *shdr; 949 int symtabindex; 950 int symstrindex; 951 int shstrindex; 952 int symcnt; 953 int strcnt; 954 char *shstrs; 955 956 shdr = NULL; 957 lf = NULL; 958 shstrs = NULL; 959 960 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td); 961 flags = FREAD; 962 error = vn_open(&nd, &flags, 0, NULL); 963 if (error != 0) 964 return (error); 965 NDFREE(&nd, NDF_ONLY_PNBUF); 966 if (nd.ni_vp->v_type != VREG) { 967 error = ENOEXEC; 968 firstpage = NULL; 969 goto out; 970 } 971 #ifdef MAC 972 error = mac_kld_check_load(curthread->td_ucred, nd.ni_vp); 973 if (error != 0) { 974 firstpage = NULL; 975 goto out; 976 } 977 #endif 978 979 /* 980 * Read the elf header from the file. 981 */ 982 firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK); 983 hdr = (Elf_Ehdr *)firstpage; 984 error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0, 985 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 986 &resid, td); 987 nbytes = PAGE_SIZE - resid; 988 if (error != 0) 989 goto out; 990 991 if (!IS_ELF(*hdr)) { 992 error = ENOEXEC; 993 goto out; 994 } 995 996 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS || 997 hdr->e_ident[EI_DATA] != ELF_TARG_DATA) { 998 link_elf_error(filename, "Unsupported file layout"); 999 error = ENOEXEC; 1000 goto out; 1001 } 1002 if (hdr->e_ident[EI_VERSION] != EV_CURRENT || 1003 hdr->e_version != EV_CURRENT) { 1004 link_elf_error(filename, "Unsupported file version"); 1005 error = ENOEXEC; 1006 goto out; 1007 } 1008 if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) { 1009 error = ENOSYS; 1010 goto out; 1011 } 1012 if (hdr->e_machine != ELF_TARG_MACH) { 1013 link_elf_error(filename, "Unsupported machine"); 1014 error = ENOEXEC; 1015 goto out; 1016 } 1017 1018 /* 1019 * We rely on the program header being in the first page. 1020 * This is not strictly required by the ABI specification, but 1021 * it seems to always true in practice. And, it simplifies 1022 * things considerably. 1023 */ 1024 if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) && 1025 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) && 1026 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes))) 1027 link_elf_error(filename, "Unreadable program headers"); 1028 1029 /* 1030 * Scan the program header entries, and save key information. 1031 * 1032 * We rely on there being exactly two load segments, text and data, 1033 * in that order. 1034 */ 1035 phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff); 1036 phlimit = phdr + hdr->e_phnum; 1037 nsegs = 0; 1038 phdyn = NULL; 1039 while (phdr < phlimit) { 1040 switch (phdr->p_type) { 1041 case PT_LOAD: 1042 if (nsegs == MAXSEGS) { 1043 link_elf_error(filename, "Too many sections"); 1044 error = ENOEXEC; 1045 goto out; 1046 } 1047 /* 1048 * XXX: We just trust they come in right order ?? 1049 */ 1050 segs[nsegs] = phdr; 1051 ++nsegs; 1052 break; 1053 1054 case PT_DYNAMIC: 1055 phdyn = phdr; 1056 break; 1057 1058 case PT_INTERP: 1059 error = ENOSYS; 1060 goto out; 1061 } 1062 1063 ++phdr; 1064 } 1065 if (phdyn == NULL) { 1066 link_elf_error(filename, "Object is not dynamically-linked"); 1067 error = ENOEXEC; 1068 goto out; 1069 } 1070 if (nsegs == 0) { 1071 link_elf_error(filename, "No sections"); 1072 error = ENOEXEC; 1073 goto out; 1074 } 1075 1076 /* 1077 * Allocate the entire address space of the object, to stake 1078 * out our contiguous region, and to establish the base 1079 * address for relocation. 1080 */ 1081 base_vaddr = trunc_page(segs[0]->p_vaddr); 1082 base_vlimit = round_page(segs[nsegs - 1]->p_vaddr + 1083 segs[nsegs - 1]->p_memsz); 1084 mapsize = base_vlimit - base_vaddr; 1085 1086 lf = linker_make_file(filename, &link_elf_class); 1087 if (lf == NULL) { 1088 error = ENOMEM; 1089 goto out; 1090 } 1091 1092 ef = (elf_file_t) lf; 1093 #ifdef SPARSE_MAPPING 1094 ef->object = vm_object_allocate(OBJT_PHYS, atop(mapsize)); 1095 if (ef->object == NULL) { 1096 error = ENOMEM; 1097 goto out; 1098 } 1099 #ifdef __amd64__ 1100 mapbase = (caddr_t)KERNBASE; 1101 #else 1102 mapbase = (caddr_t)vm_map_min(kernel_map); 1103 #endif 1104 /* 1105 * Mapping protections are downgraded after relocation processing. 1106 */ 1107 error = vm_map_find(kernel_map, ef->object, 0, 1108 (vm_offset_t *)&mapbase, mapsize, 0, VMFS_OPTIMAL_SPACE, 1109 VM_PROT_ALL, VM_PROT_ALL, 0); 1110 if (error != 0) { 1111 vm_object_deallocate(ef->object); 1112 ef->object = NULL; 1113 goto out; 1114 } 1115 #else 1116 mapbase = malloc(mapsize, M_LINKER, M_EXEC | M_WAITOK); 1117 #endif 1118 ef->address = mapbase; 1119 1120 /* 1121 * Read the text and data sections and zero the bss. 1122 */ 1123 for (i = 0; i < nsegs; i++) { 1124 segbase = mapbase + segs[i]->p_vaddr - base_vaddr; 1125 1126 #ifdef SPARSE_MAPPING 1127 /* 1128 * Consecutive segments may have different mapping permissions, 1129 * so be strict and verify that their mappings do not overlap. 1130 */ 1131 if (((vm_offset_t)segbase & PAGE_MASK) != 0) { 1132 error = EINVAL; 1133 goto out; 1134 } 1135 1136 error = vm_map_wire(kernel_map, 1137 (vm_offset_t)segbase, 1138 (vm_offset_t)segbase + round_page(segs[i]->p_memsz), 1139 VM_MAP_WIRE_SYSTEM | VM_MAP_WIRE_NOHOLES); 1140 if (error != KERN_SUCCESS) { 1141 error = ENOMEM; 1142 goto out; 1143 } 1144 #endif 1145 1146 error = vn_rdwr(UIO_READ, nd.ni_vp, 1147 segbase, segs[i]->p_filesz, segs[i]->p_offset, 1148 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1149 &resid, td); 1150 if (error != 0) 1151 goto out; 1152 bzero(segbase + segs[i]->p_filesz, 1153 segs[i]->p_memsz - segs[i]->p_filesz); 1154 } 1155 1156 #ifdef GPROF 1157 /* Update profiling information with the new text segment. */ 1158 mtx_lock(&Giant); 1159 kmupetext((uintfptr_t)(mapbase + segs[0]->p_vaddr - base_vaddr + 1160 segs[0]->p_memsz)); 1161 mtx_unlock(&Giant); 1162 #endif 1163 1164 ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr); 1165 1166 lf->address = ef->address; 1167 lf->size = mapsize; 1168 1169 error = parse_dynamic(ef); 1170 if (error != 0) 1171 goto out; 1172 error = parse_dpcpu(ef); 1173 if (error != 0) 1174 goto out; 1175 #ifdef VIMAGE 1176 error = parse_vnet(ef); 1177 if (error != 0) 1178 goto out; 1179 #endif 1180 link_elf_reloc_local(lf); 1181 1182 VOP_UNLOCK(nd.ni_vp); 1183 error = linker_load_dependencies(lf); 1184 vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY); 1185 if (error != 0) 1186 goto out; 1187 error = relocate_file(ef); 1188 if (error != 0) 1189 goto out; 1190 1191 #ifdef SPARSE_MAPPING 1192 /* 1193 * Downgrade permissions on text segment mappings now that relocation 1194 * processing is complete. Restrict permissions on read-only segments. 1195 */ 1196 for (i = 0; i < nsegs; i++) { 1197 vm_prot_t prot; 1198 1199 if (segs[i]->p_type != PT_LOAD) 1200 continue; 1201 1202 prot = VM_PROT_READ; 1203 if ((segs[i]->p_flags & PF_W) != 0) 1204 prot |= VM_PROT_WRITE; 1205 if ((segs[i]->p_flags & PF_X) != 0) 1206 prot |= VM_PROT_EXECUTE; 1207 segbase = mapbase + segs[i]->p_vaddr - base_vaddr; 1208 error = vm_map_protect(kernel_map, 1209 (vm_offset_t)segbase, 1210 (vm_offset_t)segbase + round_page(segs[i]->p_memsz), 1211 prot, FALSE); 1212 if (error != KERN_SUCCESS) { 1213 error = ENOMEM; 1214 goto out; 1215 } 1216 } 1217 #endif 1218 1219 /* 1220 * Try and load the symbol table if it's present. (you can 1221 * strip it!) 1222 */ 1223 nbytes = hdr->e_shnum * hdr->e_shentsize; 1224 if (nbytes == 0 || hdr->e_shoff == 0) 1225 goto nosyms; 1226 shdr = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO); 1227 error = vn_rdwr(UIO_READ, nd.ni_vp, 1228 (caddr_t)shdr, nbytes, hdr->e_shoff, 1229 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1230 &resid, td); 1231 if (error != 0) 1232 goto out; 1233 1234 /* Read section string table */ 1235 shstrindex = hdr->e_shstrndx; 1236 if (shstrindex != 0 && shdr[shstrindex].sh_type == SHT_STRTAB && 1237 shdr[shstrindex].sh_size != 0) { 1238 nbytes = shdr[shstrindex].sh_size; 1239 shstrs = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO); 1240 error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)shstrs, nbytes, 1241 shdr[shstrindex].sh_offset, UIO_SYSSPACE, IO_NODELOCKED, 1242 td->td_ucred, NOCRED, &resid, td); 1243 if (error) 1244 goto out; 1245 } 1246 1247 symtabindex = -1; 1248 symstrindex = -1; 1249 for (i = 0; i < hdr->e_shnum; i++) { 1250 if (shdr[i].sh_type == SHT_SYMTAB) { 1251 symtabindex = i; 1252 symstrindex = shdr[i].sh_link; 1253 } else if (shstrs != NULL && shdr[i].sh_name != 0 && 1254 strcmp(shstrs + shdr[i].sh_name, ".ctors") == 0) { 1255 /* Record relocated address and size of .ctors. */ 1256 lf->ctors_addr = mapbase + shdr[i].sh_addr - base_vaddr; 1257 lf->ctors_size = shdr[i].sh_size; 1258 } 1259 } 1260 if (symtabindex < 0 || symstrindex < 0) 1261 goto nosyms; 1262 1263 symcnt = shdr[symtabindex].sh_size; 1264 ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK); 1265 strcnt = shdr[symstrindex].sh_size; 1266 ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK); 1267 1268 error = vn_rdwr(UIO_READ, nd.ni_vp, 1269 ef->symbase, symcnt, shdr[symtabindex].sh_offset, 1270 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1271 &resid, td); 1272 if (error != 0) 1273 goto out; 1274 error = vn_rdwr(UIO_READ, nd.ni_vp, 1275 ef->strbase, strcnt, shdr[symstrindex].sh_offset, 1276 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1277 &resid, td); 1278 if (error != 0) 1279 goto out; 1280 1281 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym); 1282 ef->ddbsymtab = (const Elf_Sym *)ef->symbase; 1283 ef->ddbstrcnt = strcnt; 1284 ef->ddbstrtab = ef->strbase; 1285 1286 nosyms: 1287 1288 #ifdef __arm__ 1289 link_elf_locate_exidx(lf, shdr, hdr->e_shnum); 1290 #endif 1291 1292 error = link_elf_link_common_finish(lf); 1293 if (error != 0) 1294 goto out; 1295 1296 *result = lf; 1297 1298 out: 1299 VOP_UNLOCK(nd.ni_vp); 1300 vn_close(nd.ni_vp, FREAD, td->td_ucred, td); 1301 if (error != 0 && lf != NULL) 1302 linker_file_unload(lf, LINKER_UNLOAD_FORCE); 1303 free(shdr, M_LINKER); 1304 free(firstpage, M_LINKER); 1305 free(shstrs, M_LINKER); 1306 1307 return (error); 1308 } 1309 1310 Elf_Addr 1311 elf_relocaddr(linker_file_t lf, Elf_Addr x) 1312 { 1313 elf_file_t ef; 1314 1315 KASSERT(lf->ops->cls == (kobj_class_t)&link_elf_class, 1316 ("elf_relocaddr: unexpected linker file %p", lf)); 1317 1318 ef = (elf_file_t)lf; 1319 if (x >= ef->pcpu_start && x < ef->pcpu_stop) 1320 return ((x - ef->pcpu_start) + ef->pcpu_base); 1321 #ifdef VIMAGE 1322 if (x >= ef->vnet_start && x < ef->vnet_stop) 1323 return ((x - ef->vnet_start) + ef->vnet_base); 1324 #endif 1325 return (x); 1326 } 1327 1328 static void 1329 link_elf_unload_file(linker_file_t file) 1330 { 1331 elf_file_t ef = (elf_file_t) file; 1332 1333 if (ef->pcpu_base != 0) { 1334 dpcpu_free((void *)ef->pcpu_base, 1335 ef->pcpu_stop - ef->pcpu_start); 1336 elf_set_delete(&set_pcpu_list, ef->pcpu_start); 1337 } 1338 #ifdef VIMAGE 1339 if (ef->vnet_base != 0) { 1340 vnet_data_free((void *)ef->vnet_base, 1341 ef->vnet_stop - ef->vnet_start); 1342 elf_set_delete(&set_vnet_list, ef->vnet_start); 1343 } 1344 #endif 1345 #ifdef GDB 1346 if (ef->gdb.l_ld != NULL) { 1347 GDB_STATE(RT_DELETE); 1348 free((void *)(uintptr_t)ef->gdb.l_name, M_LINKER); 1349 link_elf_delete_gdb(&ef->gdb); 1350 GDB_STATE(RT_CONSISTENT); 1351 } 1352 #endif 1353 1354 /* Notify MD code that a module is being unloaded. */ 1355 elf_cpu_unload_file(file); 1356 1357 if (ef->preloaded) { 1358 link_elf_unload_preload(file); 1359 return; 1360 } 1361 1362 #ifdef SPARSE_MAPPING 1363 if (ef->object != NULL) { 1364 vm_map_remove(kernel_map, (vm_offset_t) ef->address, 1365 (vm_offset_t) ef->address 1366 + (ef->object->size << PAGE_SHIFT)); 1367 } 1368 #else 1369 free(ef->address, M_LINKER); 1370 #endif 1371 free(ef->symbase, M_LINKER); 1372 free(ef->strbase, M_LINKER); 1373 free(ef->ctftab, M_LINKER); 1374 free(ef->ctfoff, M_LINKER); 1375 free(ef->typoff, M_LINKER); 1376 } 1377 1378 static void 1379 link_elf_unload_preload(linker_file_t file) 1380 { 1381 1382 if (file->pathname != NULL) 1383 preload_delete_name(file->pathname); 1384 } 1385 1386 static const char * 1387 symbol_name(elf_file_t ef, Elf_Size r_info) 1388 { 1389 const Elf_Sym *ref; 1390 1391 if (ELF_R_SYM(r_info)) { 1392 ref = ef->symtab + ELF_R_SYM(r_info); 1393 return (ef->strtab + ref->st_name); 1394 } 1395 return (NULL); 1396 } 1397 1398 static int 1399 symbol_type(elf_file_t ef, Elf_Size r_info) 1400 { 1401 const Elf_Sym *ref; 1402 1403 if (ELF_R_SYM(r_info)) { 1404 ref = ef->symtab + ELF_R_SYM(r_info); 1405 return (ELF_ST_TYPE(ref->st_info)); 1406 } 1407 return (STT_NOTYPE); 1408 } 1409 1410 static int 1411 relocate_file1(elf_file_t ef, elf_lookup_fn lookup, elf_reloc_fn reloc, 1412 bool ifuncs) 1413 { 1414 const Elf_Rel *rel; 1415 const Elf_Rela *rela; 1416 const char *symname; 1417 1418 #define APPLY_RELOCS(iter, tbl, tblsize, type) do { \ 1419 for ((iter) = (tbl); (iter) != NULL && \ 1420 (iter) < (tbl) + (tblsize) / sizeof(*(iter)); (iter)++) { \ 1421 if ((symbol_type(ef, (iter)->r_info) == \ 1422 STT_GNU_IFUNC || \ 1423 elf_is_ifunc_reloc((iter)->r_info)) != ifuncs) \ 1424 continue; \ 1425 if (reloc(&ef->lf, (Elf_Addr)ef->address, \ 1426 (iter), (type), lookup)) { \ 1427 symname = symbol_name(ef, (iter)->r_info); \ 1428 printf("link_elf: symbol %s undefined\n", \ 1429 symname); \ 1430 return (ENOENT); \ 1431 } \ 1432 } \ 1433 } while (0) 1434 1435 APPLY_RELOCS(rel, ef->rel, ef->relsize, ELF_RELOC_REL); 1436 APPLY_RELOCS(rela, ef->rela, ef->relasize, ELF_RELOC_RELA); 1437 APPLY_RELOCS(rel, ef->pltrel, ef->pltrelsize, ELF_RELOC_REL); 1438 APPLY_RELOCS(rela, ef->pltrela, ef->pltrelasize, ELF_RELOC_RELA); 1439 1440 #undef APPLY_RELOCS 1441 1442 return (0); 1443 } 1444 1445 static int 1446 relocate_file(elf_file_t ef) 1447 { 1448 int error; 1449 1450 error = relocate_file1(ef, elf_lookup, elf_reloc, false); 1451 if (error == 0) 1452 error = relocate_file1(ef, elf_lookup, elf_reloc, true); 1453 return (error); 1454 } 1455 1456 /* 1457 * Hash function for symbol table lookup. Don't even think about changing 1458 * this. It is specified by the System V ABI. 1459 */ 1460 static unsigned long 1461 elf_hash(const char *name) 1462 { 1463 const unsigned char *p = (const unsigned char *) name; 1464 unsigned long h = 0; 1465 unsigned long g; 1466 1467 while (*p != '\0') { 1468 h = (h << 4) + *p++; 1469 if ((g = h & 0xf0000000) != 0) 1470 h ^= g >> 24; 1471 h &= ~g; 1472 } 1473 return (h); 1474 } 1475 1476 static int 1477 link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym) 1478 { 1479 elf_file_t ef = (elf_file_t) lf; 1480 unsigned long symnum; 1481 const Elf_Sym* symp; 1482 const char *strp; 1483 unsigned long hash; 1484 int i; 1485 1486 /* If we don't have a hash, bail. */ 1487 if (ef->buckets == NULL || ef->nbuckets == 0) { 1488 printf("link_elf_lookup_symbol: missing symbol hash table\n"); 1489 return (ENOENT); 1490 } 1491 1492 /* First, search hashed global symbols */ 1493 hash = elf_hash(name); 1494 symnum = ef->buckets[hash % ef->nbuckets]; 1495 1496 while (symnum != STN_UNDEF) { 1497 if (symnum >= ef->nchains) { 1498 printf("%s: corrupt symbol table\n", __func__); 1499 return (ENOENT); 1500 } 1501 1502 symp = ef->symtab + symnum; 1503 if (symp->st_name == 0) { 1504 printf("%s: corrupt symbol table\n", __func__); 1505 return (ENOENT); 1506 } 1507 1508 strp = ef->strtab + symp->st_name; 1509 1510 if (strcmp(name, strp) == 0) { 1511 if (symp->st_shndx != SHN_UNDEF || 1512 (symp->st_value != 0 && 1513 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1514 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC))) { 1515 *sym = (c_linker_sym_t) symp; 1516 return (0); 1517 } 1518 return (ENOENT); 1519 } 1520 1521 symnum = ef->chains[symnum]; 1522 } 1523 1524 /* If we have not found it, look at the full table (if loaded) */ 1525 if (ef->symtab == ef->ddbsymtab) 1526 return (ENOENT); 1527 1528 /* Exhaustive search */ 1529 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1530 strp = ef->ddbstrtab + symp->st_name; 1531 if (strcmp(name, strp) == 0) { 1532 if (symp->st_shndx != SHN_UNDEF || 1533 (symp->st_value != 0 && 1534 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1535 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC))) { 1536 *sym = (c_linker_sym_t) symp; 1537 return (0); 1538 } 1539 return (ENOENT); 1540 } 1541 } 1542 1543 return (ENOENT); 1544 } 1545 1546 static int 1547 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, 1548 linker_symval_t *symval) 1549 { 1550 elf_file_t ef; 1551 const Elf_Sym *es; 1552 caddr_t val; 1553 1554 ef = (elf_file_t)lf; 1555 es = (const Elf_Sym *)sym; 1556 if (es >= ef->symtab && es < (ef->symtab + ef->nchains)) { 1557 symval->name = ef->strtab + es->st_name; 1558 val = (caddr_t)ef->address + es->st_value; 1559 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC) 1560 val = ((caddr_t (*)(void))val)(); 1561 symval->value = val; 1562 symval->size = es->st_size; 1563 return (0); 1564 } 1565 if (ef->symtab == ef->ddbsymtab) 1566 return (ENOENT); 1567 if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) { 1568 symval->name = ef->ddbstrtab + es->st_name; 1569 val = (caddr_t)ef->address + es->st_value; 1570 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC) 1571 val = ((caddr_t (*)(void))val)(); 1572 symval->value = val; 1573 symval->size = es->st_size; 1574 return (0); 1575 } 1576 return (ENOENT); 1577 } 1578 1579 static int 1580 link_elf_search_symbol(linker_file_t lf, caddr_t value, 1581 c_linker_sym_t *sym, long *diffp) 1582 { 1583 elf_file_t ef = (elf_file_t) lf; 1584 u_long off = (uintptr_t) (void *) value; 1585 u_long diff = off; 1586 u_long st_value; 1587 const Elf_Sym* es; 1588 const Elf_Sym* best = NULL; 1589 int i; 1590 1591 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) { 1592 if (es->st_name == 0) 1593 continue; 1594 st_value = es->st_value + (uintptr_t) (void *) ef->address; 1595 if (off >= st_value) { 1596 if (off - st_value < diff) { 1597 diff = off - st_value; 1598 best = es; 1599 if (diff == 0) 1600 break; 1601 } else if (off - st_value == diff) { 1602 best = es; 1603 } 1604 } 1605 } 1606 if (best == NULL) 1607 *diffp = off; 1608 else 1609 *diffp = diff; 1610 *sym = (c_linker_sym_t) best; 1611 1612 return (0); 1613 } 1614 1615 /* 1616 * Look up a linker set on an ELF system. 1617 */ 1618 static int 1619 link_elf_lookup_set(linker_file_t lf, const char *name, 1620 void ***startp, void ***stopp, int *countp) 1621 { 1622 c_linker_sym_t sym; 1623 linker_symval_t symval; 1624 char *setsym; 1625 void **start, **stop; 1626 int len, error = 0, count; 1627 1628 len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */ 1629 setsym = malloc(len, M_LINKER, M_WAITOK); 1630 1631 /* get address of first entry */ 1632 snprintf(setsym, len, "%s%s", "__start_set_", name); 1633 error = link_elf_lookup_symbol(lf, setsym, &sym); 1634 if (error != 0) 1635 goto out; 1636 link_elf_symbol_values(lf, sym, &symval); 1637 if (symval.value == 0) { 1638 error = ESRCH; 1639 goto out; 1640 } 1641 start = (void **)symval.value; 1642 1643 /* get address of last entry */ 1644 snprintf(setsym, len, "%s%s", "__stop_set_", name); 1645 error = link_elf_lookup_symbol(lf, setsym, &sym); 1646 if (error != 0) 1647 goto out; 1648 link_elf_symbol_values(lf, sym, &symval); 1649 if (symval.value == 0) { 1650 error = ESRCH; 1651 goto out; 1652 } 1653 stop = (void **)symval.value; 1654 1655 /* and the number of entries */ 1656 count = stop - start; 1657 1658 /* and copy out */ 1659 if (startp != NULL) 1660 *startp = start; 1661 if (stopp != NULL) 1662 *stopp = stop; 1663 if (countp != NULL) 1664 *countp = count; 1665 1666 out: 1667 free(setsym, M_LINKER); 1668 return (error); 1669 } 1670 1671 static int 1672 link_elf_each_function_name(linker_file_t file, 1673 int (*callback)(const char *, void *), void *opaque) 1674 { 1675 elf_file_t ef = (elf_file_t)file; 1676 const Elf_Sym *symp; 1677 int i, error; 1678 1679 /* Exhaustive search */ 1680 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1681 if (symp->st_value != 0 && 1682 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1683 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) { 1684 error = callback(ef->ddbstrtab + symp->st_name, opaque); 1685 if (error != 0) 1686 return (error); 1687 } 1688 } 1689 return (0); 1690 } 1691 1692 static int 1693 link_elf_each_function_nameval(linker_file_t file, 1694 linker_function_nameval_callback_t callback, void *opaque) 1695 { 1696 linker_symval_t symval; 1697 elf_file_t ef = (elf_file_t)file; 1698 const Elf_Sym* symp; 1699 int i, error; 1700 1701 /* Exhaustive search */ 1702 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1703 if (symp->st_value != 0 && 1704 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1705 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) { 1706 error = link_elf_symbol_values(file, 1707 (c_linker_sym_t) symp, &symval); 1708 if (error != 0) 1709 return (error); 1710 error = callback(file, i, &symval, opaque); 1711 if (error != 0) 1712 return (error); 1713 } 1714 } 1715 return (0); 1716 } 1717 1718 const Elf_Sym * 1719 elf_get_sym(linker_file_t lf, Elf_Size symidx) 1720 { 1721 elf_file_t ef = (elf_file_t)lf; 1722 1723 if (symidx >= ef->nchains) 1724 return (NULL); 1725 return (ef->symtab + symidx); 1726 } 1727 1728 const char * 1729 elf_get_symname(linker_file_t lf, Elf_Size symidx) 1730 { 1731 elf_file_t ef = (elf_file_t)lf; 1732 const Elf_Sym *sym; 1733 1734 if (symidx >= ef->nchains) 1735 return (NULL); 1736 sym = ef->symtab + symidx; 1737 return (ef->strtab + sym->st_name); 1738 } 1739 1740 /* 1741 * Symbol lookup function that can be used when the symbol index is known (ie 1742 * in relocations). It uses the symbol index instead of doing a fully fledged 1743 * hash table based lookup when such is valid. For example for local symbols. 1744 * This is not only more efficient, it's also more correct. It's not always 1745 * the case that the symbol can be found through the hash table. 1746 */ 1747 static int 1748 elf_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res) 1749 { 1750 elf_file_t ef = (elf_file_t)lf; 1751 const Elf_Sym *sym; 1752 const char *symbol; 1753 Elf_Addr addr, start, base; 1754 1755 /* Don't even try to lookup the symbol if the index is bogus. */ 1756 if (symidx >= ef->nchains) { 1757 *res = 0; 1758 return (EINVAL); 1759 } 1760 1761 sym = ef->symtab + symidx; 1762 1763 /* 1764 * Don't do a full lookup when the symbol is local. It may even 1765 * fail because it may not be found through the hash table. 1766 */ 1767 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) { 1768 /* Force lookup failure when we have an insanity. */ 1769 if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0) { 1770 *res = 0; 1771 return (EINVAL); 1772 } 1773 *res = ((Elf_Addr)ef->address + sym->st_value); 1774 return (0); 1775 } 1776 1777 /* 1778 * XXX we can avoid doing a hash table based lookup for global 1779 * symbols as well. This however is not always valid, so we'll 1780 * just do it the hard way for now. Performance tweaks can 1781 * always be added. 1782 */ 1783 1784 symbol = ef->strtab + sym->st_name; 1785 1786 /* Force a lookup failure if the symbol name is bogus. */ 1787 if (*symbol == 0) { 1788 *res = 0; 1789 return (EINVAL); 1790 } 1791 1792 addr = ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps)); 1793 if (addr == 0 && ELF_ST_BIND(sym->st_info) != STB_WEAK) { 1794 *res = 0; 1795 return (EINVAL); 1796 } 1797 1798 if (elf_set_find(&set_pcpu_list, addr, &start, &base)) 1799 addr = addr - start + base; 1800 #ifdef VIMAGE 1801 else if (elf_set_find(&set_vnet_list, addr, &start, &base)) 1802 addr = addr - start + base; 1803 #endif 1804 *res = addr; 1805 return (0); 1806 } 1807 1808 static void 1809 link_elf_reloc_local(linker_file_t lf) 1810 { 1811 const Elf_Rel *rellim; 1812 const Elf_Rel *rel; 1813 const Elf_Rela *relalim; 1814 const Elf_Rela *rela; 1815 elf_file_t ef = (elf_file_t)lf; 1816 1817 /* Perform relocations without addend if there are any: */ 1818 if ((rel = ef->rel) != NULL) { 1819 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize); 1820 while (rel < rellim) { 1821 elf_reloc_local(lf, (Elf_Addr)ef->address, rel, 1822 ELF_RELOC_REL, elf_lookup); 1823 rel++; 1824 } 1825 } 1826 1827 /* Perform relocations with addend if there are any: */ 1828 if ((rela = ef->rela) != NULL) { 1829 relalim = (const Elf_Rela *) 1830 ((const char *)ef->rela + ef->relasize); 1831 while (rela < relalim) { 1832 elf_reloc_local(lf, (Elf_Addr)ef->address, rela, 1833 ELF_RELOC_RELA, elf_lookup); 1834 rela++; 1835 } 1836 } 1837 } 1838 1839 static long 1840 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab) 1841 { 1842 elf_file_t ef = (elf_file_t)lf; 1843 1844 *symtab = ef->ddbsymtab; 1845 1846 if (*symtab == NULL) 1847 return (0); 1848 1849 return (ef->ddbsymcnt); 1850 } 1851 1852 static long 1853 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab) 1854 { 1855 elf_file_t ef = (elf_file_t)lf; 1856 1857 *strtab = ef->ddbstrtab; 1858 1859 if (*strtab == NULL) 1860 return (0); 1861 1862 return (ef->ddbstrcnt); 1863 } 1864 1865 #if defined(__i386__) || defined(__amd64__) || defined(__aarch64__) || defined(__powerpc__) 1866 /* 1867 * Use this lookup routine when performing relocations early during boot. 1868 * The generic lookup routine depends on kobj, which is not initialized 1869 * at that point. 1870 */ 1871 static int 1872 elf_lookup_ifunc(linker_file_t lf, Elf_Size symidx, int deps __unused, 1873 Elf_Addr *res) 1874 { 1875 elf_file_t ef; 1876 const Elf_Sym *symp; 1877 caddr_t val; 1878 1879 ef = (elf_file_t)lf; 1880 symp = ef->symtab + symidx; 1881 if (ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC) { 1882 val = (caddr_t)ef->address + symp->st_value; 1883 *res = ((Elf_Addr (*)(void))val)(); 1884 return (0); 1885 } 1886 return (ENOENT); 1887 } 1888 1889 void 1890 link_elf_ireloc(caddr_t kmdp) 1891 { 1892 struct elf_file eff; 1893 elf_file_t ef; 1894 1895 ef = &eff; 1896 1897 bzero_early(ef, sizeof(*ef)); 1898 1899 ef->modptr = kmdp; 1900 ef->dynamic = (Elf_Dyn *)&_DYNAMIC; 1901 1902 #ifdef RELOCATABLE_KERNEL 1903 ef->address = (caddr_t) (__startkernel - KERNBASE); 1904 #else 1905 ef->address = 0; 1906 #endif 1907 parse_dynamic(ef); 1908 1909 link_elf_preload_parse_symbols(ef); 1910 relocate_file1(ef, elf_lookup_ifunc, elf_reloc, true); 1911 } 1912 #endif 1913