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 #include <sys/mutex.h> 44 #include <sys/mount.h> 45 #include <sys/pcpu.h> 46 #include <sys/proc.h> 47 #include <sys/namei.h> 48 #include <sys/fcntl.h> 49 #include <sys/vnode.h> 50 #include <sys/linker.h> 51 52 #include <machine/elf.h> 53 54 #include <net/vnet.h> 55 56 #include <security/mac/mac_framework.h> 57 58 #include <vm/vm.h> 59 #include <vm/vm_param.h> 60 #ifdef SPARSE_MAPPING 61 #include <vm/vm_object.h> 62 #include <vm/vm_kern.h> 63 #include <vm/vm_extern.h> 64 #endif 65 #include <vm/pmap.h> 66 #include <vm/vm_map.h> 67 68 #include <sys/link_elf.h> 69 70 #ifdef DDB_CTF 71 #include <sys/zlib.h> 72 #endif 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 { 0, 0 } 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 extern vm_offset_t __startkernel, __endkernel; 392 393 static void 394 link_elf_init(void* arg) 395 { 396 Elf_Dyn *dp; 397 Elf_Addr *ctors_addrp; 398 Elf_Size *ctors_sizep; 399 caddr_t modptr, baseptr, sizeptr; 400 elf_file_t ef; 401 char *modname; 402 403 linker_add_class(&link_elf_class); 404 405 dp = (Elf_Dyn *)&_DYNAMIC; 406 modname = NULL; 407 modptr = preload_search_by_type("elf" __XSTRING(__ELF_WORD_SIZE) " kernel"); 408 if (modptr == NULL) 409 modptr = preload_search_by_type("elf kernel"); 410 modname = (char *)preload_search_info(modptr, MODINFO_NAME); 411 if (modname == NULL) 412 modname = "kernel"; 413 linker_kernel_file = linker_make_file(modname, &link_elf_class); 414 if (linker_kernel_file == NULL) 415 panic("%s: Can't create linker structures for kernel", 416 __func__); 417 418 ef = (elf_file_t) linker_kernel_file; 419 ef->preloaded = 1; 420 #ifdef __powerpc__ 421 ef->address = (caddr_t) (__startkernel - KERNBASE); 422 #else 423 ef->address = 0; 424 #endif 425 #ifdef SPARSE_MAPPING 426 ef->object = 0; 427 #endif 428 ef->dynamic = dp; 429 430 if (dp != NULL) 431 parse_dynamic(ef); 432 #ifdef __powerpc__ 433 linker_kernel_file->address = (caddr_t)__startkernel; 434 linker_kernel_file->size = (intptr_t)(__endkernel - __startkernel); 435 #else 436 linker_kernel_file->address += KERNBASE; 437 linker_kernel_file->size = -(intptr_t)linker_kernel_file->address; 438 #endif 439 440 if (modptr != NULL) { 441 ef->modptr = modptr; 442 baseptr = preload_search_info(modptr, MODINFO_ADDR); 443 if (baseptr != NULL) 444 linker_kernel_file->address = *(caddr_t *)baseptr; 445 sizeptr = preload_search_info(modptr, MODINFO_SIZE); 446 if (sizeptr != NULL) 447 linker_kernel_file->size = *(size_t *)sizeptr; 448 ctors_addrp = (Elf_Addr *)preload_search_info(modptr, 449 MODINFO_METADATA | MODINFOMD_CTORS_ADDR); 450 ctors_sizep = (Elf_Size *)preload_search_info(modptr, 451 MODINFO_METADATA | MODINFOMD_CTORS_SIZE); 452 if (ctors_addrp != NULL && ctors_sizep != NULL) { 453 linker_kernel_file->ctors_addr = ef->address + 454 *ctors_addrp; 455 linker_kernel_file->ctors_size = *ctors_sizep; 456 } 457 } 458 (void)link_elf_preload_parse_symbols(ef); 459 460 #ifdef GDB 461 r_debug.r_map = NULL; 462 r_debug.r_brk = r_debug_state; 463 r_debug.r_state = RT_CONSISTENT; 464 #endif 465 466 (void)link_elf_link_common_finish(linker_kernel_file); 467 linker_kernel_file->flags |= LINKER_FILE_LINKED; 468 TAILQ_INIT(&set_pcpu_list); 469 #ifdef VIMAGE 470 TAILQ_INIT(&set_vnet_list); 471 #endif 472 } 473 474 SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_THIRD, link_elf_init, NULL); 475 476 static int 477 link_elf_preload_parse_symbols(elf_file_t ef) 478 { 479 caddr_t pointer; 480 caddr_t ssym, esym, base; 481 caddr_t strtab; 482 int strcnt; 483 Elf_Sym *symtab; 484 int symcnt; 485 486 if (ef->modptr == NULL) 487 return (0); 488 pointer = preload_search_info(ef->modptr, 489 MODINFO_METADATA | MODINFOMD_SSYM); 490 if (pointer == NULL) 491 return (0); 492 ssym = *(caddr_t *)pointer; 493 pointer = preload_search_info(ef->modptr, 494 MODINFO_METADATA | MODINFOMD_ESYM); 495 if (pointer == NULL) 496 return (0); 497 esym = *(caddr_t *)pointer; 498 499 base = ssym; 500 501 symcnt = *(long *)base; 502 base += sizeof(long); 503 symtab = (Elf_Sym *)base; 504 base += roundup(symcnt, sizeof(long)); 505 506 if (base > esym || base < ssym) { 507 printf("Symbols are corrupt!\n"); 508 return (EINVAL); 509 } 510 511 strcnt = *(long *)base; 512 base += sizeof(long); 513 strtab = base; 514 base += roundup(strcnt, sizeof(long)); 515 516 if (base > esym || base < ssym) { 517 printf("Symbols are corrupt!\n"); 518 return (EINVAL); 519 } 520 521 ef->ddbsymtab = symtab; 522 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym); 523 ef->ddbstrtab = strtab; 524 ef->ddbstrcnt = strcnt; 525 526 return (0); 527 } 528 529 static int 530 parse_dynamic(elf_file_t ef) 531 { 532 Elf_Dyn *dp; 533 int plttype = DT_REL; 534 535 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) { 536 switch (dp->d_tag) { 537 case DT_HASH: 538 { 539 /* From src/libexec/rtld-elf/rtld.c */ 540 const Elf_Hashelt *hashtab = (const Elf_Hashelt *) 541 (ef->address + dp->d_un.d_ptr); 542 ef->nbuckets = hashtab[0]; 543 ef->nchains = hashtab[1]; 544 ef->buckets = hashtab + 2; 545 ef->chains = ef->buckets + ef->nbuckets; 546 break; 547 } 548 case DT_STRTAB: 549 ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr); 550 break; 551 case DT_STRSZ: 552 ef->strsz = dp->d_un.d_val; 553 break; 554 case DT_SYMTAB: 555 ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr); 556 break; 557 case DT_SYMENT: 558 if (dp->d_un.d_val != sizeof(Elf_Sym)) 559 return (ENOEXEC); 560 break; 561 case DT_PLTGOT: 562 ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr); 563 break; 564 case DT_REL: 565 ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr); 566 break; 567 case DT_RELSZ: 568 ef->relsize = dp->d_un.d_val; 569 break; 570 case DT_RELENT: 571 if (dp->d_un.d_val != sizeof(Elf_Rel)) 572 return (ENOEXEC); 573 break; 574 case DT_JMPREL: 575 ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr); 576 break; 577 case DT_PLTRELSZ: 578 ef->pltrelsize = dp->d_un.d_val; 579 break; 580 case DT_RELA: 581 ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr); 582 break; 583 case DT_RELASZ: 584 ef->relasize = dp->d_un.d_val; 585 break; 586 case DT_RELAENT: 587 if (dp->d_un.d_val != sizeof(Elf_Rela)) 588 return (ENOEXEC); 589 break; 590 case DT_PLTREL: 591 plttype = dp->d_un.d_val; 592 if (plttype != DT_REL && plttype != DT_RELA) 593 return (ENOEXEC); 594 break; 595 #ifdef GDB 596 case DT_DEBUG: 597 dp->d_un.d_ptr = (Elf_Addr)&r_debug; 598 break; 599 #endif 600 } 601 } 602 603 if (plttype == DT_RELA) { 604 ef->pltrela = (const Elf_Rela *)ef->pltrel; 605 ef->pltrel = NULL; 606 ef->pltrelasize = ef->pltrelsize; 607 ef->pltrelsize = 0; 608 } 609 610 ef->ddbsymtab = ef->symtab; 611 ef->ddbsymcnt = ef->nchains; 612 ef->ddbstrtab = ef->strtab; 613 ef->ddbstrcnt = ef->strsz; 614 615 return (0); 616 } 617 618 #define LS_PADDING 0x90909090 619 static int 620 parse_dpcpu(elf_file_t ef) 621 { 622 int error, size; 623 #if defined(__i386__) 624 uint32_t pad; 625 #endif 626 627 ef->pcpu_start = 0; 628 ef->pcpu_stop = 0; 629 error = link_elf_lookup_set(&ef->lf, "pcpu", (void ***)&ef->pcpu_start, 630 (void ***)&ef->pcpu_stop, NULL); 631 /* Error just means there is no pcpu set to relocate. */ 632 if (error != 0) 633 return (0); 634 size = (uintptr_t)ef->pcpu_stop - (uintptr_t)ef->pcpu_start; 635 /* Empty set? */ 636 if (size < 1) 637 return (0); 638 #if defined(__i386__) 639 /* In case we do find __start/stop_set_ symbols double-check. */ 640 if (size < 4) { 641 uprintf("Kernel module '%s' must be recompiled with " 642 "linker script\n", ef->lf.pathname); 643 return (ENOEXEC); 644 } 645 646 /* Padding from linker-script correct? */ 647 pad = *(uint32_t *)((uintptr_t)ef->pcpu_stop - sizeof(pad)); 648 if (pad != LS_PADDING) { 649 uprintf("Kernel module '%s' must be recompiled with " 650 "linker script, invalid padding %#04x (%#04x)\n", 651 ef->lf.pathname, pad, LS_PADDING); 652 return (ENOEXEC); 653 } 654 /* If we only have valid padding, nothing to do. */ 655 if (size == 4) 656 return (0); 657 #endif 658 /* 659 * Allocate space in the primary pcpu area. Copy in our 660 * initialization from the data section and then initialize 661 * all per-cpu storage from that. 662 */ 663 ef->pcpu_base = (Elf_Addr)(uintptr_t)dpcpu_alloc(size); 664 if (ef->pcpu_base == 0) { 665 printf("%s: pcpu module space is out of space; " 666 "cannot allocate %d for %s\n", 667 __func__, size, ef->lf.pathname); 668 return (ENOSPC); 669 } 670 memcpy((void *)ef->pcpu_base, (void *)ef->pcpu_start, size); 671 dpcpu_copy((void *)ef->pcpu_base, size); 672 elf_set_add(&set_pcpu_list, ef->pcpu_start, ef->pcpu_stop, 673 ef->pcpu_base); 674 675 return (0); 676 } 677 678 #ifdef VIMAGE 679 static int 680 parse_vnet(elf_file_t ef) 681 { 682 int error, size; 683 #if defined(__i386__) 684 uint32_t pad; 685 #endif 686 687 ef->vnet_start = 0; 688 ef->vnet_stop = 0; 689 error = link_elf_lookup_set(&ef->lf, "vnet", (void ***)&ef->vnet_start, 690 (void ***)&ef->vnet_stop, NULL); 691 /* Error just means there is no vnet data set to relocate. */ 692 if (error != 0) 693 return (0); 694 size = (uintptr_t)ef->vnet_stop - (uintptr_t)ef->vnet_start; 695 /* Empty set? */ 696 if (size < 1) 697 return (0); 698 #if defined(__i386__) 699 /* In case we do find __start/stop_set_ symbols double-check. */ 700 if (size < 4) { 701 uprintf("Kernel module '%s' must be recompiled with " 702 "linker script\n", ef->lf.pathname); 703 return (ENOEXEC); 704 } 705 706 /* Padding from linker-script correct? */ 707 pad = *(uint32_t *)((uintptr_t)ef->vnet_stop - sizeof(pad)); 708 if (pad != LS_PADDING) { 709 uprintf("Kernel module '%s' must be recompiled with " 710 "linker script, invalid padding %#04x (%#04x)\n", 711 ef->lf.pathname, pad, LS_PADDING); 712 return (ENOEXEC); 713 } 714 /* If we only have valid padding, nothing to do. */ 715 if (size == 4) 716 return (0); 717 #endif 718 /* 719 * Allocate space in the primary vnet area. Copy in our 720 * initialization from the data section and then initialize 721 * all per-vnet storage from that. 722 */ 723 ef->vnet_base = (Elf_Addr)(uintptr_t)vnet_data_alloc(size); 724 if (ef->vnet_base == 0) { 725 printf("%s: vnet module space is out of space; " 726 "cannot allocate %d for %s\n", 727 __func__, size, ef->lf.pathname); 728 return (ENOSPC); 729 } 730 memcpy((void *)ef->vnet_base, (void *)ef->vnet_start, size); 731 vnet_data_copy((void *)ef->vnet_base, size); 732 elf_set_add(&set_vnet_list, ef->vnet_start, ef->vnet_stop, 733 ef->vnet_base); 734 735 return (0); 736 } 737 #endif 738 #undef LS_PADDING 739 740 static int 741 link_elf_link_preload(linker_class_t cls, 742 const char* filename, linker_file_t *result) 743 { 744 Elf_Addr *ctors_addrp; 745 Elf_Size *ctors_sizep; 746 caddr_t modptr, baseptr, sizeptr, dynptr; 747 char *type; 748 elf_file_t ef; 749 linker_file_t lf; 750 int error; 751 vm_offset_t dp; 752 753 /* Look to see if we have the file preloaded */ 754 modptr = preload_search_by_name(filename); 755 if (modptr == NULL) 756 return (ENOENT); 757 758 type = (char *)preload_search_info(modptr, MODINFO_TYPE); 759 baseptr = preload_search_info(modptr, MODINFO_ADDR); 760 sizeptr = preload_search_info(modptr, MODINFO_SIZE); 761 dynptr = preload_search_info(modptr, 762 MODINFO_METADATA | MODINFOMD_DYNAMIC); 763 if (type == NULL || 764 (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) " module") != 0 && 765 strcmp(type, "elf module") != 0)) 766 return (EFTYPE); 767 if (baseptr == NULL || sizeptr == NULL || dynptr == NULL) 768 return (EINVAL); 769 770 lf = linker_make_file(filename, &link_elf_class); 771 if (lf == NULL) 772 return (ENOMEM); 773 774 ef = (elf_file_t) lf; 775 ef->preloaded = 1; 776 ef->modptr = modptr; 777 ef->address = *(caddr_t *)baseptr; 778 #ifdef SPARSE_MAPPING 779 ef->object = 0; 780 #endif 781 dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr; 782 ef->dynamic = (Elf_Dyn *)dp; 783 lf->address = ef->address; 784 lf->size = *(size_t *)sizeptr; 785 786 ctors_addrp = (Elf_Addr *)preload_search_info(modptr, 787 MODINFO_METADATA | MODINFOMD_CTORS_ADDR); 788 ctors_sizep = (Elf_Size *)preload_search_info(modptr, 789 MODINFO_METADATA | MODINFOMD_CTORS_SIZE); 790 if (ctors_addrp != NULL && ctors_sizep != NULL) { 791 lf->ctors_addr = ef->address + *ctors_addrp; 792 lf->ctors_size = *ctors_sizep; 793 } 794 795 error = parse_dynamic(ef); 796 if (error == 0) 797 error = parse_dpcpu(ef); 798 #ifdef VIMAGE 799 if (error == 0) 800 error = parse_vnet(ef); 801 #endif 802 if (error != 0) { 803 linker_file_unload(lf, LINKER_UNLOAD_FORCE); 804 return (error); 805 } 806 link_elf_reloc_local(lf); 807 *result = lf; 808 return (0); 809 } 810 811 static int 812 link_elf_link_preload_finish(linker_file_t lf) 813 { 814 elf_file_t ef; 815 int error; 816 817 ef = (elf_file_t) lf; 818 error = relocate_file(ef); 819 if (error != 0) 820 return (error); 821 (void)link_elf_preload_parse_symbols(ef); 822 823 return (link_elf_link_common_finish(lf)); 824 } 825 826 static int 827 link_elf_load_file(linker_class_t cls, const char* filename, 828 linker_file_t* result) 829 { 830 struct nameidata nd; 831 struct thread* td = curthread; /* XXX */ 832 Elf_Ehdr *hdr; 833 caddr_t firstpage; 834 int nbytes, i; 835 Elf_Phdr *phdr; 836 Elf_Phdr *phlimit; 837 Elf_Phdr *segs[MAXSEGS]; 838 int nsegs; 839 Elf_Phdr *phdyn; 840 caddr_t mapbase; 841 size_t mapsize; 842 Elf_Addr base_vaddr; 843 Elf_Addr base_vlimit; 844 int error = 0; 845 ssize_t resid; 846 int flags; 847 elf_file_t ef; 848 linker_file_t lf; 849 Elf_Shdr *shdr; 850 int symtabindex; 851 int symstrindex; 852 int shstrindex; 853 int symcnt; 854 int strcnt; 855 char *shstrs; 856 857 shdr = NULL; 858 lf = NULL; 859 shstrs = NULL; 860 861 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td); 862 flags = FREAD; 863 error = vn_open(&nd, &flags, 0, NULL); 864 if (error != 0) 865 return (error); 866 NDFREE(&nd, NDF_ONLY_PNBUF); 867 if (nd.ni_vp->v_type != VREG) { 868 error = ENOEXEC; 869 firstpage = NULL; 870 goto out; 871 } 872 #ifdef MAC 873 error = mac_kld_check_load(curthread->td_ucred, nd.ni_vp); 874 if (error != 0) { 875 firstpage = NULL; 876 goto out; 877 } 878 #endif 879 880 /* 881 * Read the elf header from the file. 882 */ 883 firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK); 884 hdr = (Elf_Ehdr *)firstpage; 885 error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0, 886 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 887 &resid, td); 888 nbytes = PAGE_SIZE - resid; 889 if (error != 0) 890 goto out; 891 892 if (!IS_ELF(*hdr)) { 893 error = ENOEXEC; 894 goto out; 895 } 896 897 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS || 898 hdr->e_ident[EI_DATA] != ELF_TARG_DATA) { 899 link_elf_error(filename, "Unsupported file layout"); 900 error = ENOEXEC; 901 goto out; 902 } 903 if (hdr->e_ident[EI_VERSION] != EV_CURRENT || 904 hdr->e_version != EV_CURRENT) { 905 link_elf_error(filename, "Unsupported file version"); 906 error = ENOEXEC; 907 goto out; 908 } 909 if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) { 910 error = ENOSYS; 911 goto out; 912 } 913 if (hdr->e_machine != ELF_TARG_MACH) { 914 link_elf_error(filename, "Unsupported machine"); 915 error = ENOEXEC; 916 goto out; 917 } 918 919 /* 920 * We rely on the program header being in the first page. 921 * This is not strictly required by the ABI specification, but 922 * it seems to always true in practice. And, it simplifies 923 * things considerably. 924 */ 925 if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) && 926 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) && 927 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes))) 928 link_elf_error(filename, "Unreadable program headers"); 929 930 /* 931 * Scan the program header entries, and save key information. 932 * 933 * We rely on there being exactly two load segments, text and data, 934 * in that order. 935 */ 936 phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff); 937 phlimit = phdr + hdr->e_phnum; 938 nsegs = 0; 939 phdyn = NULL; 940 while (phdr < phlimit) { 941 switch (phdr->p_type) { 942 case PT_LOAD: 943 if (nsegs == MAXSEGS) { 944 link_elf_error(filename, "Too many sections"); 945 error = ENOEXEC; 946 goto out; 947 } 948 /* 949 * XXX: We just trust they come in right order ?? 950 */ 951 segs[nsegs] = phdr; 952 ++nsegs; 953 break; 954 955 case PT_DYNAMIC: 956 phdyn = phdr; 957 break; 958 959 case PT_INTERP: 960 error = ENOSYS; 961 goto out; 962 } 963 964 ++phdr; 965 } 966 if (phdyn == NULL) { 967 link_elf_error(filename, "Object is not dynamically-linked"); 968 error = ENOEXEC; 969 goto out; 970 } 971 if (nsegs == 0) { 972 link_elf_error(filename, "No sections"); 973 error = ENOEXEC; 974 goto out; 975 } 976 977 /* 978 * Allocate the entire address space of the object, to stake 979 * out our contiguous region, and to establish the base 980 * address for relocation. 981 */ 982 base_vaddr = trunc_page(segs[0]->p_vaddr); 983 base_vlimit = round_page(segs[nsegs - 1]->p_vaddr + 984 segs[nsegs - 1]->p_memsz); 985 mapsize = base_vlimit - base_vaddr; 986 987 lf = linker_make_file(filename, &link_elf_class); 988 if (lf == NULL) { 989 error = ENOMEM; 990 goto out; 991 } 992 993 ef = (elf_file_t) lf; 994 #ifdef SPARSE_MAPPING 995 ef->object = vm_object_allocate(OBJT_DEFAULT, mapsize >> PAGE_SHIFT); 996 if (ef->object == NULL) { 997 error = ENOMEM; 998 goto out; 999 } 1000 ef->address = (caddr_t) vm_map_min(kernel_map); 1001 error = vm_map_find(kernel_map, ef->object, 0, 1002 (vm_offset_t *) &ef->address, mapsize, 0, VMFS_OPTIMAL_SPACE, 1003 VM_PROT_ALL, VM_PROT_ALL, 0); 1004 if (error != 0) { 1005 vm_object_deallocate(ef->object); 1006 ef->object = 0; 1007 goto out; 1008 } 1009 #else 1010 ef->address = malloc(mapsize, M_LINKER, M_EXEC | M_WAITOK); 1011 #endif 1012 mapbase = ef->address; 1013 1014 /* 1015 * Read the text and data sections and zero the bss. 1016 */ 1017 for (i = 0; i < nsegs; i++) { 1018 caddr_t segbase = mapbase + segs[i]->p_vaddr - base_vaddr; 1019 error = vn_rdwr(UIO_READ, nd.ni_vp, 1020 segbase, segs[i]->p_filesz, segs[i]->p_offset, 1021 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1022 &resid, td); 1023 if (error != 0) 1024 goto out; 1025 bzero(segbase + segs[i]->p_filesz, 1026 segs[i]->p_memsz - segs[i]->p_filesz); 1027 1028 #ifdef SPARSE_MAPPING 1029 /* 1030 * Wire down the pages 1031 */ 1032 error = vm_map_wire(kernel_map, 1033 (vm_offset_t) segbase, 1034 (vm_offset_t) segbase + segs[i]->p_memsz, 1035 VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES); 1036 if (error != KERN_SUCCESS) { 1037 error = ENOMEM; 1038 goto out; 1039 } 1040 #endif 1041 } 1042 1043 #ifdef GPROF 1044 /* Update profiling information with the new text segment. */ 1045 mtx_lock(&Giant); 1046 kmupetext((uintfptr_t)(mapbase + segs[0]->p_vaddr - base_vaddr + 1047 segs[0]->p_memsz)); 1048 mtx_unlock(&Giant); 1049 #endif 1050 1051 ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr); 1052 1053 lf->address = ef->address; 1054 lf->size = mapsize; 1055 1056 error = parse_dynamic(ef); 1057 if (error != 0) 1058 goto out; 1059 error = parse_dpcpu(ef); 1060 if (error != 0) 1061 goto out; 1062 #ifdef VIMAGE 1063 error = parse_vnet(ef); 1064 if (error != 0) 1065 goto out; 1066 #endif 1067 link_elf_reloc_local(lf); 1068 1069 VOP_UNLOCK(nd.ni_vp, 0); 1070 error = linker_load_dependencies(lf); 1071 vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY); 1072 if (error != 0) 1073 goto out; 1074 error = relocate_file(ef); 1075 if (error != 0) 1076 goto out; 1077 1078 /* 1079 * Try and load the symbol table if it's present. (you can 1080 * strip it!) 1081 */ 1082 nbytes = hdr->e_shnum * hdr->e_shentsize; 1083 if (nbytes == 0 || hdr->e_shoff == 0) 1084 goto nosyms; 1085 shdr = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO); 1086 error = vn_rdwr(UIO_READ, nd.ni_vp, 1087 (caddr_t)shdr, nbytes, hdr->e_shoff, 1088 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1089 &resid, td); 1090 if (error != 0) 1091 goto out; 1092 1093 /* Read section string table */ 1094 shstrindex = hdr->e_shstrndx; 1095 if (shstrindex != 0 && shdr[shstrindex].sh_type == SHT_STRTAB && 1096 shdr[shstrindex].sh_size != 0) { 1097 nbytes = shdr[shstrindex].sh_size; 1098 shstrs = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO); 1099 error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)shstrs, nbytes, 1100 shdr[shstrindex].sh_offset, UIO_SYSSPACE, IO_NODELOCKED, 1101 td->td_ucred, NOCRED, &resid, td); 1102 if (error) 1103 goto out; 1104 } 1105 1106 symtabindex = -1; 1107 symstrindex = -1; 1108 for (i = 0; i < hdr->e_shnum; i++) { 1109 if (shdr[i].sh_type == SHT_SYMTAB) { 1110 symtabindex = i; 1111 symstrindex = shdr[i].sh_link; 1112 } else if (shstrs != NULL && shdr[i].sh_name != 0 && 1113 strcmp(shstrs + shdr[i].sh_name, ".ctors") == 0) { 1114 /* Record relocated address and size of .ctors. */ 1115 lf->ctors_addr = mapbase + shdr[i].sh_addr - base_vaddr; 1116 lf->ctors_size = shdr[i].sh_size; 1117 } 1118 } 1119 if (symtabindex < 0 || symstrindex < 0) 1120 goto nosyms; 1121 1122 symcnt = shdr[symtabindex].sh_size; 1123 ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK); 1124 strcnt = shdr[symstrindex].sh_size; 1125 ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK); 1126 1127 error = vn_rdwr(UIO_READ, nd.ni_vp, 1128 ef->symbase, symcnt, shdr[symtabindex].sh_offset, 1129 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1130 &resid, td); 1131 if (error != 0) 1132 goto out; 1133 error = vn_rdwr(UIO_READ, nd.ni_vp, 1134 ef->strbase, strcnt, shdr[symstrindex].sh_offset, 1135 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1136 &resid, td); 1137 if (error != 0) 1138 goto out; 1139 1140 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym); 1141 ef->ddbsymtab = (const Elf_Sym *)ef->symbase; 1142 ef->ddbstrcnt = strcnt; 1143 ef->ddbstrtab = ef->strbase; 1144 1145 nosyms: 1146 error = link_elf_link_common_finish(lf); 1147 if (error != 0) 1148 goto out; 1149 1150 *result = lf; 1151 1152 out: 1153 VOP_UNLOCK(nd.ni_vp, 0); 1154 vn_close(nd.ni_vp, FREAD, td->td_ucred, td); 1155 if (error != 0 && lf != NULL) 1156 linker_file_unload(lf, LINKER_UNLOAD_FORCE); 1157 free(shdr, M_LINKER); 1158 free(firstpage, M_LINKER); 1159 free(shstrs, M_LINKER); 1160 1161 return (error); 1162 } 1163 1164 Elf_Addr 1165 elf_relocaddr(linker_file_t lf, Elf_Addr x) 1166 { 1167 elf_file_t ef; 1168 1169 ef = (elf_file_t)lf; 1170 if (x >= ef->pcpu_start && x < ef->pcpu_stop) 1171 return ((x - ef->pcpu_start) + ef->pcpu_base); 1172 #ifdef VIMAGE 1173 if (x >= ef->vnet_start && x < ef->vnet_stop) 1174 return ((x - ef->vnet_start) + ef->vnet_base); 1175 #endif 1176 return (x); 1177 } 1178 1179 1180 static void 1181 link_elf_unload_file(linker_file_t file) 1182 { 1183 elf_file_t ef = (elf_file_t) file; 1184 1185 if (ef->pcpu_base != 0) { 1186 dpcpu_free((void *)ef->pcpu_base, 1187 ef->pcpu_stop - ef->pcpu_start); 1188 elf_set_delete(&set_pcpu_list, ef->pcpu_start); 1189 } 1190 #ifdef VIMAGE 1191 if (ef->vnet_base != 0) { 1192 vnet_data_free((void *)ef->vnet_base, 1193 ef->vnet_stop - ef->vnet_start); 1194 elf_set_delete(&set_vnet_list, ef->vnet_start); 1195 } 1196 #endif 1197 #ifdef GDB 1198 if (ef->gdb.l_ld != NULL) { 1199 GDB_STATE(RT_DELETE); 1200 free((void *)(uintptr_t)ef->gdb.l_name, M_LINKER); 1201 link_elf_delete_gdb(&ef->gdb); 1202 GDB_STATE(RT_CONSISTENT); 1203 } 1204 #endif 1205 1206 /* Notify MD code that a module is being unloaded. */ 1207 elf_cpu_unload_file(file); 1208 1209 if (ef->preloaded) { 1210 link_elf_unload_preload(file); 1211 return; 1212 } 1213 1214 #ifdef SPARSE_MAPPING 1215 if (ef->object != NULL) { 1216 vm_map_remove(kernel_map, (vm_offset_t) ef->address, 1217 (vm_offset_t) ef->address 1218 + (ef->object->size << PAGE_SHIFT)); 1219 } 1220 #else 1221 free(ef->address, M_LINKER); 1222 #endif 1223 free(ef->symbase, M_LINKER); 1224 free(ef->strbase, M_LINKER); 1225 free(ef->ctftab, M_LINKER); 1226 free(ef->ctfoff, M_LINKER); 1227 free(ef->typoff, M_LINKER); 1228 } 1229 1230 static void 1231 link_elf_unload_preload(linker_file_t file) 1232 { 1233 if (file->pathname != NULL) 1234 preload_delete_name(file->pathname); 1235 } 1236 1237 static const char * 1238 symbol_name(elf_file_t ef, Elf_Size r_info) 1239 { 1240 const Elf_Sym *ref; 1241 1242 if (ELF_R_SYM(r_info)) { 1243 ref = ef->symtab + ELF_R_SYM(r_info); 1244 return (ef->strtab + ref->st_name); 1245 } 1246 return (NULL); 1247 } 1248 1249 static int 1250 symbol_type(elf_file_t ef, Elf_Size r_info) 1251 { 1252 const Elf_Sym *ref; 1253 1254 if (ELF_R_SYM(r_info)) { 1255 ref = ef->symtab + ELF_R_SYM(r_info); 1256 return (ELF_ST_TYPE(ref->st_info)); 1257 } 1258 return (STT_NOTYPE); 1259 } 1260 1261 static int 1262 relocate_file1(elf_file_t ef, elf_lookup_fn lookup, elf_reloc_fn reloc, 1263 bool ifuncs) 1264 { 1265 const Elf_Rel *rel; 1266 const Elf_Rela *rela; 1267 const char *symname; 1268 1269 #define APPLY_RELOCS(iter, tbl, tblsize, type) do { \ 1270 for ((iter) = (tbl); (iter) != NULL && \ 1271 (iter) < (tbl) + (tblsize) / sizeof(*(iter)); (iter)++) { \ 1272 if ((symbol_type(ef, (iter)->r_info) == \ 1273 STT_GNU_IFUNC || \ 1274 elf_is_ifunc_reloc((iter)->r_info)) != ifuncs) \ 1275 continue; \ 1276 if (reloc(&ef->lf, (Elf_Addr)ef->address, \ 1277 (iter), (type), lookup)) { \ 1278 symname = symbol_name(ef, (iter)->r_info); \ 1279 printf("link_elf: symbol %s undefined\n", \ 1280 symname); \ 1281 return (ENOENT); \ 1282 } \ 1283 } \ 1284 } while (0) 1285 1286 APPLY_RELOCS(rel, ef->rel, ef->relsize, ELF_RELOC_REL); 1287 APPLY_RELOCS(rela, ef->rela, ef->relasize, ELF_RELOC_RELA); 1288 APPLY_RELOCS(rel, ef->pltrel, ef->pltrelsize, ELF_RELOC_REL); 1289 APPLY_RELOCS(rela, ef->pltrela, ef->pltrelasize, ELF_RELOC_RELA); 1290 1291 #undef APPLY_RELOCS 1292 1293 return (0); 1294 } 1295 1296 static int 1297 relocate_file(elf_file_t ef) 1298 { 1299 int error; 1300 1301 error = relocate_file1(ef, elf_lookup, elf_reloc, false); 1302 if (error == 0) 1303 error = relocate_file1(ef, elf_lookup, elf_reloc, true); 1304 return (error); 1305 } 1306 1307 /* 1308 * Hash function for symbol table lookup. Don't even think about changing 1309 * this. It is specified by the System V ABI. 1310 */ 1311 static unsigned long 1312 elf_hash(const char *name) 1313 { 1314 const unsigned char *p = (const unsigned char *) name; 1315 unsigned long h = 0; 1316 unsigned long g; 1317 1318 while (*p != '\0') { 1319 h = (h << 4) + *p++; 1320 if ((g = h & 0xf0000000) != 0) 1321 h ^= g >> 24; 1322 h &= ~g; 1323 } 1324 return (h); 1325 } 1326 1327 static int 1328 link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym) 1329 { 1330 elf_file_t ef = (elf_file_t) lf; 1331 unsigned long symnum; 1332 const Elf_Sym* symp; 1333 const char *strp; 1334 unsigned long hash; 1335 int i; 1336 1337 /* If we don't have a hash, bail. */ 1338 if (ef->buckets == NULL || ef->nbuckets == 0) { 1339 printf("link_elf_lookup_symbol: missing symbol hash table\n"); 1340 return (ENOENT); 1341 } 1342 1343 /* First, search hashed global symbols */ 1344 hash = elf_hash(name); 1345 symnum = ef->buckets[hash % ef->nbuckets]; 1346 1347 while (symnum != STN_UNDEF) { 1348 if (symnum >= ef->nchains) { 1349 printf("%s: corrupt symbol table\n", __func__); 1350 return (ENOENT); 1351 } 1352 1353 symp = ef->symtab + symnum; 1354 if (symp->st_name == 0) { 1355 printf("%s: corrupt symbol table\n", __func__); 1356 return (ENOENT); 1357 } 1358 1359 strp = ef->strtab + symp->st_name; 1360 1361 if (strcmp(name, strp) == 0) { 1362 if (symp->st_shndx != SHN_UNDEF || 1363 (symp->st_value != 0 && 1364 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1365 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC))) { 1366 *sym = (c_linker_sym_t) symp; 1367 return (0); 1368 } 1369 return (ENOENT); 1370 } 1371 1372 symnum = ef->chains[symnum]; 1373 } 1374 1375 /* If we have not found it, look at the full table (if loaded) */ 1376 if (ef->symtab == ef->ddbsymtab) 1377 return (ENOENT); 1378 1379 /* Exhaustive search */ 1380 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1381 strp = ef->ddbstrtab + symp->st_name; 1382 if (strcmp(name, strp) == 0) { 1383 if (symp->st_shndx != SHN_UNDEF || 1384 (symp->st_value != 0 && 1385 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1386 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC))) { 1387 *sym = (c_linker_sym_t) symp; 1388 return (0); 1389 } 1390 return (ENOENT); 1391 } 1392 } 1393 1394 return (ENOENT); 1395 } 1396 1397 static int 1398 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, 1399 linker_symval_t *symval) 1400 { 1401 elf_file_t ef; 1402 const Elf_Sym *es; 1403 caddr_t val; 1404 1405 ef = (elf_file_t)lf; 1406 es = (const Elf_Sym *)sym; 1407 if (es >= ef->symtab && es < (ef->symtab + ef->nchains)) { 1408 symval->name = ef->strtab + es->st_name; 1409 val = (caddr_t)ef->address + es->st_value; 1410 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC) 1411 val = ((caddr_t (*)(void))val)(); 1412 symval->value = val; 1413 symval->size = es->st_size; 1414 return (0); 1415 } 1416 if (ef->symtab == ef->ddbsymtab) 1417 return (ENOENT); 1418 if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) { 1419 symval->name = ef->ddbstrtab + es->st_name; 1420 val = (caddr_t)ef->address + es->st_value; 1421 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC) 1422 val = ((caddr_t (*)(void))val)(); 1423 symval->value = val; 1424 symval->size = es->st_size; 1425 return (0); 1426 } 1427 return (ENOENT); 1428 } 1429 1430 static int 1431 link_elf_search_symbol(linker_file_t lf, caddr_t value, 1432 c_linker_sym_t *sym, long *diffp) 1433 { 1434 elf_file_t ef = (elf_file_t) lf; 1435 u_long off = (uintptr_t) (void *) value; 1436 u_long diff = off; 1437 u_long st_value; 1438 const Elf_Sym* es; 1439 const Elf_Sym* best = NULL; 1440 int i; 1441 1442 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) { 1443 if (es->st_name == 0) 1444 continue; 1445 st_value = es->st_value + (uintptr_t) (void *) ef->address; 1446 if (off >= st_value) { 1447 if (off - st_value < diff) { 1448 diff = off - st_value; 1449 best = es; 1450 if (diff == 0) 1451 break; 1452 } else if (off - st_value == diff) { 1453 best = es; 1454 } 1455 } 1456 } 1457 if (best == NULL) 1458 *diffp = off; 1459 else 1460 *diffp = diff; 1461 *sym = (c_linker_sym_t) best; 1462 1463 return (0); 1464 } 1465 1466 /* 1467 * Look up a linker set on an ELF system. 1468 */ 1469 static int 1470 link_elf_lookup_set(linker_file_t lf, const char *name, 1471 void ***startp, void ***stopp, int *countp) 1472 { 1473 c_linker_sym_t sym; 1474 linker_symval_t symval; 1475 char *setsym; 1476 void **start, **stop; 1477 int len, error = 0, count; 1478 1479 len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */ 1480 setsym = malloc(len, M_LINKER, M_WAITOK); 1481 1482 /* get address of first entry */ 1483 snprintf(setsym, len, "%s%s", "__start_set_", name); 1484 error = link_elf_lookup_symbol(lf, setsym, &sym); 1485 if (error != 0) 1486 goto out; 1487 link_elf_symbol_values(lf, sym, &symval); 1488 if (symval.value == 0) { 1489 error = ESRCH; 1490 goto out; 1491 } 1492 start = (void **)symval.value; 1493 1494 /* get address of last entry */ 1495 snprintf(setsym, len, "%s%s", "__stop_set_", name); 1496 error = link_elf_lookup_symbol(lf, setsym, &sym); 1497 if (error != 0) 1498 goto out; 1499 link_elf_symbol_values(lf, sym, &symval); 1500 if (symval.value == 0) { 1501 error = ESRCH; 1502 goto out; 1503 } 1504 stop = (void **)symval.value; 1505 1506 /* and the number of entries */ 1507 count = stop - start; 1508 1509 /* and copy out */ 1510 if (startp != NULL) 1511 *startp = start; 1512 if (stopp != NULL) 1513 *stopp = stop; 1514 if (countp != NULL) 1515 *countp = count; 1516 1517 out: 1518 free(setsym, M_LINKER); 1519 return (error); 1520 } 1521 1522 static int 1523 link_elf_each_function_name(linker_file_t file, 1524 int (*callback)(const char *, void *), void *opaque) 1525 { 1526 elf_file_t ef = (elf_file_t)file; 1527 const Elf_Sym *symp; 1528 int i, error; 1529 1530 /* Exhaustive search */ 1531 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1532 if (symp->st_value != 0 && 1533 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1534 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) { 1535 error = callback(ef->ddbstrtab + symp->st_name, opaque); 1536 if (error != 0) 1537 return (error); 1538 } 1539 } 1540 return (0); 1541 } 1542 1543 static int 1544 link_elf_each_function_nameval(linker_file_t file, 1545 linker_function_nameval_callback_t callback, void *opaque) 1546 { 1547 linker_symval_t symval; 1548 elf_file_t ef = (elf_file_t)file; 1549 const Elf_Sym* symp; 1550 int i, error; 1551 1552 /* Exhaustive search */ 1553 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1554 if (symp->st_value != 0 && 1555 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1556 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) { 1557 error = link_elf_symbol_values(file, 1558 (c_linker_sym_t) symp, &symval); 1559 if (error != 0) 1560 return (error); 1561 error = callback(file, i, &symval, opaque); 1562 if (error != 0) 1563 return (error); 1564 } 1565 } 1566 return (0); 1567 } 1568 1569 const Elf_Sym * 1570 elf_get_sym(linker_file_t lf, Elf_Size symidx) 1571 { 1572 elf_file_t ef = (elf_file_t)lf; 1573 1574 if (symidx >= ef->nchains) 1575 return (NULL); 1576 return (ef->symtab + symidx); 1577 } 1578 1579 const char * 1580 elf_get_symname(linker_file_t lf, Elf_Size symidx) 1581 { 1582 elf_file_t ef = (elf_file_t)lf; 1583 const Elf_Sym *sym; 1584 1585 if (symidx >= ef->nchains) 1586 return (NULL); 1587 sym = ef->symtab + symidx; 1588 return (ef->strtab + sym->st_name); 1589 } 1590 1591 /* 1592 * Symbol lookup function that can be used when the symbol index is known (ie 1593 * in relocations). It uses the symbol index instead of doing a fully fledged 1594 * hash table based lookup when such is valid. For example for local symbols. 1595 * This is not only more efficient, it's also more correct. It's not always 1596 * the case that the symbol can be found through the hash table. 1597 */ 1598 static int 1599 elf_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res) 1600 { 1601 elf_file_t ef = (elf_file_t)lf; 1602 const Elf_Sym *sym; 1603 const char *symbol; 1604 Elf_Addr addr, start, base; 1605 1606 /* Don't even try to lookup the symbol if the index is bogus. */ 1607 if (symidx >= ef->nchains) { 1608 *res = 0; 1609 return (EINVAL); 1610 } 1611 1612 sym = ef->symtab + symidx; 1613 1614 /* 1615 * Don't do a full lookup when the symbol is local. It may even 1616 * fail because it may not be found through the hash table. 1617 */ 1618 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) { 1619 /* Force lookup failure when we have an insanity. */ 1620 if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0) { 1621 *res = 0; 1622 return (EINVAL); 1623 } 1624 *res = ((Elf_Addr)ef->address + sym->st_value); 1625 return (0); 1626 } 1627 1628 /* 1629 * XXX we can avoid doing a hash table based lookup for global 1630 * symbols as well. This however is not always valid, so we'll 1631 * just do it the hard way for now. Performance tweaks can 1632 * always be added. 1633 */ 1634 1635 symbol = ef->strtab + sym->st_name; 1636 1637 /* Force a lookup failure if the symbol name is bogus. */ 1638 if (*symbol == 0) { 1639 *res = 0; 1640 return (EINVAL); 1641 } 1642 1643 addr = ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps)); 1644 if (addr == 0 && ELF_ST_BIND(sym->st_info) != STB_WEAK) { 1645 *res = 0; 1646 return (EINVAL); 1647 } 1648 1649 if (elf_set_find(&set_pcpu_list, addr, &start, &base)) 1650 addr = addr - start + base; 1651 #ifdef VIMAGE 1652 else if (elf_set_find(&set_vnet_list, addr, &start, &base)) 1653 addr = addr - start + base; 1654 #endif 1655 *res = addr; 1656 return (0); 1657 } 1658 1659 static void 1660 link_elf_reloc_local(linker_file_t lf) 1661 { 1662 const Elf_Rel *rellim; 1663 const Elf_Rel *rel; 1664 const Elf_Rela *relalim; 1665 const Elf_Rela *rela; 1666 elf_file_t ef = (elf_file_t)lf; 1667 1668 /* Perform relocations without addend if there are any: */ 1669 if ((rel = ef->rel) != NULL) { 1670 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize); 1671 while (rel < rellim) { 1672 elf_reloc_local(lf, (Elf_Addr)ef->address, rel, 1673 ELF_RELOC_REL, elf_lookup); 1674 rel++; 1675 } 1676 } 1677 1678 /* Perform relocations with addend if there are any: */ 1679 if ((rela = ef->rela) != NULL) { 1680 relalim = (const Elf_Rela *) 1681 ((const char *)ef->rela + ef->relasize); 1682 while (rela < relalim) { 1683 elf_reloc_local(lf, (Elf_Addr)ef->address, rela, 1684 ELF_RELOC_RELA, elf_lookup); 1685 rela++; 1686 } 1687 } 1688 } 1689 1690 static long 1691 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab) 1692 { 1693 elf_file_t ef = (elf_file_t)lf; 1694 1695 *symtab = ef->ddbsymtab; 1696 1697 if (*symtab == NULL) 1698 return (0); 1699 1700 return (ef->ddbsymcnt); 1701 } 1702 1703 static long 1704 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab) 1705 { 1706 elf_file_t ef = (elf_file_t)lf; 1707 1708 *strtab = ef->ddbstrtab; 1709 1710 if (*strtab == NULL) 1711 return (0); 1712 1713 return (ef->ddbstrcnt); 1714 } 1715 1716 #if defined(__i386__) || defined(__amd64__) || defined(__aarch64__) 1717 /* 1718 * Use this lookup routine when performing relocations early during boot. 1719 * The generic lookup routine depends on kobj, which is not initialized 1720 * at that point. 1721 */ 1722 static int 1723 elf_lookup_ifunc(linker_file_t lf, Elf_Size symidx, int deps __unused, 1724 Elf_Addr *res) 1725 { 1726 elf_file_t ef; 1727 const Elf_Sym *symp; 1728 caddr_t val; 1729 1730 ef = (elf_file_t)lf; 1731 symp = ef->symtab + symidx; 1732 if (ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC) { 1733 val = (caddr_t)ef->address + symp->st_value; 1734 *res = ((Elf_Addr (*)(void))val)(); 1735 return (0); 1736 } 1737 return (ENOENT); 1738 } 1739 1740 void 1741 link_elf_ireloc(caddr_t kmdp) 1742 { 1743 struct elf_file eff; 1744 elf_file_t ef; 1745 1746 ef = &eff; 1747 1748 bzero_early(ef, sizeof(*ef)); 1749 1750 ef->modptr = kmdp; 1751 ef->dynamic = (Elf_Dyn *)&_DYNAMIC; 1752 parse_dynamic(ef); 1753 ef->address = 0; 1754 link_elf_preload_parse_symbols(ef); 1755 relocate_file1(ef, elf_lookup_ifunc, elf_reloc, true); 1756 } 1757 #endif 1758