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