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