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 error, size; 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 /* 635 * Allocate space in the primary pcpu area. Copy in our 636 * initialization from the data section and then initialize 637 * all per-cpu storage from that. 638 */ 639 ef->pcpu_base = (Elf_Addr)(uintptr_t)dpcpu_alloc(size); 640 if (ef->pcpu_base == 0) 641 return (ENOSPC); 642 memcpy((void *)ef->pcpu_base, (void *)ef->pcpu_start, size); 643 dpcpu_copy((void *)ef->pcpu_base, size); 644 elf_set_add(&set_pcpu_list, ef->pcpu_start, ef->pcpu_stop, 645 ef->pcpu_base); 646 647 return (0); 648 } 649 650 #ifdef VIMAGE 651 static int 652 parse_vnet(elf_file_t ef) 653 { 654 int error, size; 655 656 ef->vnet_start = 0; 657 ef->vnet_stop = 0; 658 error = link_elf_lookup_set(&ef->lf, "vnet", (void ***)&ef->vnet_start, 659 (void ***)&ef->vnet_stop, NULL); 660 /* Error just means there is no vnet data set to relocate. */ 661 if (error != 0) 662 return (0); 663 size = (uintptr_t)ef->vnet_stop - (uintptr_t)ef->vnet_start; 664 /* Empty set? */ 665 if (size < 1) 666 return (0); 667 /* 668 * Allocate space in the primary vnet area. Copy in our 669 * initialization from the data section and then initialize 670 * all per-vnet storage from that. 671 */ 672 ef->vnet_base = (Elf_Addr)(uintptr_t)vnet_data_alloc(size); 673 if (ef->vnet_base == 0) 674 return (ENOSPC); 675 memcpy((void *)ef->vnet_base, (void *)ef->vnet_start, size); 676 vnet_data_copy((void *)ef->vnet_base, size); 677 elf_set_add(&set_vnet_list, ef->vnet_start, ef->vnet_stop, 678 ef->vnet_base); 679 680 return (0); 681 } 682 #endif 683 684 static int 685 link_elf_link_preload(linker_class_t cls, 686 const char* filename, linker_file_t *result) 687 { 688 Elf_Addr *ctors_addrp; 689 Elf_Size *ctors_sizep; 690 caddr_t modptr, baseptr, sizeptr, dynptr; 691 char *type; 692 elf_file_t ef; 693 linker_file_t lf; 694 int error; 695 vm_offset_t dp; 696 697 /* Look to see if we have the file preloaded */ 698 modptr = preload_search_by_name(filename); 699 if (modptr == NULL) 700 return (ENOENT); 701 702 type = (char *)preload_search_info(modptr, MODINFO_TYPE); 703 baseptr = preload_search_info(modptr, MODINFO_ADDR); 704 sizeptr = preload_search_info(modptr, MODINFO_SIZE); 705 dynptr = preload_search_info(modptr, 706 MODINFO_METADATA | MODINFOMD_DYNAMIC); 707 if (type == NULL || 708 (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) " module") != 0 && 709 strcmp(type, "elf module") != 0)) 710 return (EFTYPE); 711 if (baseptr == NULL || sizeptr == NULL || dynptr == NULL) 712 return (EINVAL); 713 714 lf = linker_make_file(filename, &link_elf_class); 715 if (lf == NULL) 716 return (ENOMEM); 717 718 ef = (elf_file_t) lf; 719 ef->preloaded = 1; 720 ef->modptr = modptr; 721 ef->address = *(caddr_t *)baseptr; 722 #ifdef SPARSE_MAPPING 723 ef->object = 0; 724 #endif 725 dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr; 726 ef->dynamic = (Elf_Dyn *)dp; 727 lf->address = ef->address; 728 lf->size = *(size_t *)sizeptr; 729 730 ctors_addrp = (Elf_Addr *)preload_search_info(modptr, 731 MODINFO_METADATA | MODINFOMD_CTORS_ADDR); 732 ctors_sizep = (Elf_Size *)preload_search_info(modptr, 733 MODINFO_METADATA | MODINFOMD_CTORS_SIZE); 734 if (ctors_addrp != NULL && ctors_sizep != NULL) { 735 lf->ctors_addr = ef->address + *ctors_addrp; 736 lf->ctors_size = *ctors_sizep; 737 } 738 739 error = parse_dynamic(ef); 740 if (error == 0) 741 error = parse_dpcpu(ef); 742 #ifdef VIMAGE 743 if (error == 0) 744 error = parse_vnet(ef); 745 #endif 746 if (error != 0) { 747 linker_file_unload(lf, LINKER_UNLOAD_FORCE); 748 return (error); 749 } 750 link_elf_reloc_local(lf); 751 *result = lf; 752 return (0); 753 } 754 755 static int 756 link_elf_link_preload_finish(linker_file_t lf) 757 { 758 elf_file_t ef; 759 int error; 760 761 ef = (elf_file_t) lf; 762 error = relocate_file(ef); 763 if (error != 0) 764 return (error); 765 (void)link_elf_preload_parse_symbols(ef); 766 767 return (link_elf_link_common_finish(lf)); 768 } 769 770 static int 771 link_elf_load_file(linker_class_t cls, const char* filename, 772 linker_file_t* result) 773 { 774 struct nameidata nd; 775 struct thread* td = curthread; /* XXX */ 776 Elf_Ehdr *hdr; 777 caddr_t firstpage; 778 int nbytes, i; 779 Elf_Phdr *phdr; 780 Elf_Phdr *phlimit; 781 Elf_Phdr *segs[MAXSEGS]; 782 int nsegs; 783 Elf_Phdr *phdyn; 784 caddr_t mapbase; 785 size_t mapsize; 786 Elf_Addr base_vaddr; 787 Elf_Addr base_vlimit; 788 int error = 0; 789 ssize_t resid; 790 int flags; 791 elf_file_t ef; 792 linker_file_t lf; 793 Elf_Shdr *shdr; 794 int symtabindex; 795 int symstrindex; 796 int shstrindex; 797 int symcnt; 798 int strcnt; 799 char *shstrs; 800 801 shdr = NULL; 802 lf = NULL; 803 shstrs = NULL; 804 805 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td); 806 flags = FREAD; 807 error = vn_open(&nd, &flags, 0, NULL); 808 if (error != 0) 809 return (error); 810 NDFREE(&nd, NDF_ONLY_PNBUF); 811 if (nd.ni_vp->v_type != VREG) { 812 error = ENOEXEC; 813 firstpage = NULL; 814 goto out; 815 } 816 #ifdef MAC 817 error = mac_kld_check_load(curthread->td_ucred, nd.ni_vp); 818 if (error != 0) { 819 firstpage = NULL; 820 goto out; 821 } 822 #endif 823 824 /* 825 * Read the elf header from the file. 826 */ 827 firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK); 828 hdr = (Elf_Ehdr *)firstpage; 829 error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0, 830 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 831 &resid, td); 832 nbytes = PAGE_SIZE - resid; 833 if (error != 0) 834 goto out; 835 836 if (!IS_ELF(*hdr)) { 837 error = ENOEXEC; 838 goto out; 839 } 840 841 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS || 842 hdr->e_ident[EI_DATA] != ELF_TARG_DATA) { 843 link_elf_error(filename, "Unsupported file layout"); 844 error = ENOEXEC; 845 goto out; 846 } 847 if (hdr->e_ident[EI_VERSION] != EV_CURRENT || 848 hdr->e_version != EV_CURRENT) { 849 link_elf_error(filename, "Unsupported file version"); 850 error = ENOEXEC; 851 goto out; 852 } 853 if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) { 854 error = ENOSYS; 855 goto out; 856 } 857 if (hdr->e_machine != ELF_TARG_MACH) { 858 link_elf_error(filename, "Unsupported machine"); 859 error = ENOEXEC; 860 goto out; 861 } 862 863 /* 864 * We rely on the program header being in the first page. 865 * This is not strictly required by the ABI specification, but 866 * it seems to always true in practice. And, it simplifies 867 * things considerably. 868 */ 869 if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) && 870 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) && 871 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes))) 872 link_elf_error(filename, "Unreadable program headers"); 873 874 /* 875 * Scan the program header entries, and save key information. 876 * 877 * We rely on there being exactly two load segments, text and data, 878 * in that order. 879 */ 880 phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff); 881 phlimit = phdr + hdr->e_phnum; 882 nsegs = 0; 883 phdyn = NULL; 884 while (phdr < phlimit) { 885 switch (phdr->p_type) { 886 case PT_LOAD: 887 if (nsegs == MAXSEGS) { 888 link_elf_error(filename, "Too many sections"); 889 error = ENOEXEC; 890 goto out; 891 } 892 /* 893 * XXX: We just trust they come in right order ?? 894 */ 895 segs[nsegs] = phdr; 896 ++nsegs; 897 break; 898 899 case PT_DYNAMIC: 900 phdyn = phdr; 901 break; 902 903 case PT_INTERP: 904 error = ENOSYS; 905 goto out; 906 } 907 908 ++phdr; 909 } 910 if (phdyn == NULL) { 911 link_elf_error(filename, "Object is not dynamically-linked"); 912 error = ENOEXEC; 913 goto out; 914 } 915 if (nsegs == 0) { 916 link_elf_error(filename, "No sections"); 917 error = ENOEXEC; 918 goto out; 919 } 920 921 /* 922 * Allocate the entire address space of the object, to stake 923 * out our contiguous region, and to establish the base 924 * address for relocation. 925 */ 926 base_vaddr = trunc_page(segs[0]->p_vaddr); 927 base_vlimit = round_page(segs[nsegs - 1]->p_vaddr + 928 segs[nsegs - 1]->p_memsz); 929 mapsize = base_vlimit - base_vaddr; 930 931 lf = linker_make_file(filename, &link_elf_class); 932 if (lf == NULL) { 933 error = ENOMEM; 934 goto out; 935 } 936 937 ef = (elf_file_t) lf; 938 #ifdef SPARSE_MAPPING 939 ef->object = vm_object_allocate(OBJT_DEFAULT, mapsize >> PAGE_SHIFT); 940 if (ef->object == NULL) { 941 error = ENOMEM; 942 goto out; 943 } 944 ef->address = (caddr_t) vm_map_min(kernel_map); 945 error = vm_map_find(kernel_map, ef->object, 0, 946 (vm_offset_t *) &ef->address, mapsize, 0, VMFS_OPTIMAL_SPACE, 947 VM_PROT_ALL, VM_PROT_ALL, 0); 948 if (error != 0) { 949 vm_object_deallocate(ef->object); 950 ef->object = 0; 951 goto out; 952 } 953 #else 954 ef->address = malloc(mapsize, M_LINKER, M_EXEC | M_WAITOK); 955 #endif 956 mapbase = ef->address; 957 958 /* 959 * Read the text and data sections and zero the bss. 960 */ 961 for (i = 0; i < nsegs; i++) { 962 caddr_t segbase = mapbase + segs[i]->p_vaddr - base_vaddr; 963 error = vn_rdwr(UIO_READ, nd.ni_vp, 964 segbase, segs[i]->p_filesz, segs[i]->p_offset, 965 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 966 &resid, td); 967 if (error != 0) 968 goto out; 969 bzero(segbase + segs[i]->p_filesz, 970 segs[i]->p_memsz - segs[i]->p_filesz); 971 972 #ifdef SPARSE_MAPPING 973 /* 974 * Wire down the pages 975 */ 976 error = vm_map_wire(kernel_map, 977 (vm_offset_t) segbase, 978 (vm_offset_t) segbase + segs[i]->p_memsz, 979 VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES); 980 if (error != KERN_SUCCESS) { 981 error = ENOMEM; 982 goto out; 983 } 984 #endif 985 } 986 987 #ifdef GPROF 988 /* Update profiling information with the new text segment. */ 989 mtx_lock(&Giant); 990 kmupetext((uintfptr_t)(mapbase + segs[0]->p_vaddr - base_vaddr + 991 segs[0]->p_memsz)); 992 mtx_unlock(&Giant); 993 #endif 994 995 ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr); 996 997 lf->address = ef->address; 998 lf->size = mapsize; 999 1000 error = parse_dynamic(ef); 1001 if (error != 0) 1002 goto out; 1003 error = parse_dpcpu(ef); 1004 if (error != 0) 1005 goto out; 1006 #ifdef VIMAGE 1007 error = parse_vnet(ef); 1008 if (error != 0) 1009 goto out; 1010 #endif 1011 link_elf_reloc_local(lf); 1012 1013 VOP_UNLOCK(nd.ni_vp, 0); 1014 error = linker_load_dependencies(lf); 1015 vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY); 1016 if (error != 0) 1017 goto out; 1018 error = relocate_file(ef); 1019 if (error != 0) 1020 goto out; 1021 1022 /* 1023 * Try and load the symbol table if it's present. (you can 1024 * strip it!) 1025 */ 1026 nbytes = hdr->e_shnum * hdr->e_shentsize; 1027 if (nbytes == 0 || hdr->e_shoff == 0) 1028 goto nosyms; 1029 shdr = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO); 1030 error = vn_rdwr(UIO_READ, nd.ni_vp, 1031 (caddr_t)shdr, nbytes, hdr->e_shoff, 1032 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1033 &resid, td); 1034 if (error != 0) 1035 goto out; 1036 1037 /* Read section string table */ 1038 shstrindex = hdr->e_shstrndx; 1039 if (shstrindex != 0 && shdr[shstrindex].sh_type == SHT_STRTAB && 1040 shdr[shstrindex].sh_size != 0) { 1041 nbytes = shdr[shstrindex].sh_size; 1042 shstrs = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO); 1043 error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)shstrs, nbytes, 1044 shdr[shstrindex].sh_offset, UIO_SYSSPACE, IO_NODELOCKED, 1045 td->td_ucred, NOCRED, &resid, td); 1046 if (error) 1047 goto out; 1048 } 1049 1050 symtabindex = -1; 1051 symstrindex = -1; 1052 for (i = 0; i < hdr->e_shnum; i++) { 1053 if (shdr[i].sh_type == SHT_SYMTAB) { 1054 symtabindex = i; 1055 symstrindex = shdr[i].sh_link; 1056 } else if (shstrs != NULL && shdr[i].sh_name != 0 && 1057 strcmp(shstrs + shdr[i].sh_name, ".ctors") == 0) { 1058 /* Record relocated address and size of .ctors. */ 1059 lf->ctors_addr = mapbase + shdr[i].sh_addr - base_vaddr; 1060 lf->ctors_size = shdr[i].sh_size; 1061 } 1062 } 1063 if (symtabindex < 0 || symstrindex < 0) 1064 goto nosyms; 1065 1066 symcnt = shdr[symtabindex].sh_size; 1067 ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK); 1068 strcnt = shdr[symstrindex].sh_size; 1069 ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK); 1070 1071 error = vn_rdwr(UIO_READ, nd.ni_vp, 1072 ef->symbase, symcnt, shdr[symtabindex].sh_offset, 1073 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1074 &resid, td); 1075 if (error != 0) 1076 goto out; 1077 error = vn_rdwr(UIO_READ, nd.ni_vp, 1078 ef->strbase, strcnt, shdr[symstrindex].sh_offset, 1079 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1080 &resid, td); 1081 if (error != 0) 1082 goto out; 1083 1084 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym); 1085 ef->ddbsymtab = (const Elf_Sym *)ef->symbase; 1086 ef->ddbstrcnt = strcnt; 1087 ef->ddbstrtab = ef->strbase; 1088 1089 nosyms: 1090 error = link_elf_link_common_finish(lf); 1091 if (error != 0) 1092 goto out; 1093 1094 *result = lf; 1095 1096 out: 1097 VOP_UNLOCK(nd.ni_vp, 0); 1098 vn_close(nd.ni_vp, FREAD, td->td_ucred, td); 1099 if (error != 0 && lf != NULL) 1100 linker_file_unload(lf, LINKER_UNLOAD_FORCE); 1101 free(shdr, M_LINKER); 1102 free(firstpage, M_LINKER); 1103 free(shstrs, M_LINKER); 1104 1105 return (error); 1106 } 1107 1108 Elf_Addr 1109 elf_relocaddr(linker_file_t lf, Elf_Addr x) 1110 { 1111 elf_file_t ef; 1112 1113 ef = (elf_file_t)lf; 1114 if (x >= ef->pcpu_start && x < ef->pcpu_stop) 1115 return ((x - ef->pcpu_start) + ef->pcpu_base); 1116 #ifdef VIMAGE 1117 if (x >= ef->vnet_start && x < ef->vnet_stop) 1118 return ((x - ef->vnet_start) + ef->vnet_base); 1119 #endif 1120 return (x); 1121 } 1122 1123 1124 static void 1125 link_elf_unload_file(linker_file_t file) 1126 { 1127 elf_file_t ef = (elf_file_t) file; 1128 1129 if (ef->pcpu_base != 0) { 1130 dpcpu_free((void *)ef->pcpu_base, 1131 ef->pcpu_stop - ef->pcpu_start); 1132 elf_set_delete(&set_pcpu_list, ef->pcpu_start); 1133 } 1134 #ifdef VIMAGE 1135 if (ef->vnet_base != 0) { 1136 vnet_data_free((void *)ef->vnet_base, 1137 ef->vnet_stop - ef->vnet_start); 1138 elf_set_delete(&set_vnet_list, ef->vnet_start); 1139 } 1140 #endif 1141 #ifdef GDB 1142 if (ef->gdb.l_ld != NULL) { 1143 GDB_STATE(RT_DELETE); 1144 free((void *)(uintptr_t)ef->gdb.l_name, M_LINKER); 1145 link_elf_delete_gdb(&ef->gdb); 1146 GDB_STATE(RT_CONSISTENT); 1147 } 1148 #endif 1149 1150 /* Notify MD code that a module is being unloaded. */ 1151 elf_cpu_unload_file(file); 1152 1153 if (ef->preloaded) { 1154 link_elf_unload_preload(file); 1155 return; 1156 } 1157 1158 #ifdef SPARSE_MAPPING 1159 if (ef->object != NULL) { 1160 vm_map_remove(kernel_map, (vm_offset_t) ef->address, 1161 (vm_offset_t) ef->address 1162 + (ef->object->size << PAGE_SHIFT)); 1163 } 1164 #else 1165 free(ef->address, M_LINKER); 1166 #endif 1167 free(ef->symbase, M_LINKER); 1168 free(ef->strbase, M_LINKER); 1169 free(ef->ctftab, M_LINKER); 1170 free(ef->ctfoff, M_LINKER); 1171 free(ef->typoff, M_LINKER); 1172 } 1173 1174 static void 1175 link_elf_unload_preload(linker_file_t file) 1176 { 1177 if (file->pathname != NULL) 1178 preload_delete_name(file->pathname); 1179 } 1180 1181 static const char * 1182 symbol_name(elf_file_t ef, Elf_Size r_info) 1183 { 1184 const Elf_Sym *ref; 1185 1186 if (ELF_R_SYM(r_info)) { 1187 ref = ef->symtab + ELF_R_SYM(r_info); 1188 return (ef->strtab + ref->st_name); 1189 } 1190 return (NULL); 1191 } 1192 1193 static int 1194 symbol_type(elf_file_t ef, Elf_Size r_info) 1195 { 1196 const Elf_Sym *ref; 1197 1198 if (ELF_R_SYM(r_info)) { 1199 ref = ef->symtab + ELF_R_SYM(r_info); 1200 return (ELF_ST_TYPE(ref->st_info)); 1201 } 1202 return (STT_NOTYPE); 1203 } 1204 1205 static int 1206 relocate_file1(elf_file_t ef, elf_lookup_fn lookup, elf_reloc_fn reloc, 1207 bool ifuncs) 1208 { 1209 const Elf_Rel *rel; 1210 const Elf_Rela *rela; 1211 const char *symname; 1212 1213 #define APPLY_RELOCS(iter, tbl, tblsize, type) do { \ 1214 for ((iter) = (tbl); (iter) != NULL && \ 1215 (iter) < (tbl) + (tblsize) / sizeof(*(iter)); (iter)++) { \ 1216 if ((symbol_type(ef, (iter)->r_info) == \ 1217 STT_GNU_IFUNC || \ 1218 elf_is_ifunc_reloc((iter)->r_info)) != ifuncs) \ 1219 continue; \ 1220 if (reloc(&ef->lf, (Elf_Addr)ef->address, \ 1221 (iter), (type), lookup)) { \ 1222 symname = symbol_name(ef, (iter)->r_info); \ 1223 printf("link_elf: symbol %s undefined\n", \ 1224 symname); \ 1225 return (ENOENT); \ 1226 } \ 1227 } \ 1228 } while (0) 1229 1230 APPLY_RELOCS(rel, ef->rel, ef->relsize, ELF_RELOC_REL); 1231 APPLY_RELOCS(rela, ef->rela, ef->relasize, ELF_RELOC_RELA); 1232 APPLY_RELOCS(rel, ef->pltrel, ef->pltrelsize, ELF_RELOC_REL); 1233 APPLY_RELOCS(rela, ef->pltrela, ef->pltrelasize, ELF_RELOC_RELA); 1234 1235 #undef APPLY_RELOCS 1236 1237 return (0); 1238 } 1239 1240 static int 1241 relocate_file(elf_file_t ef) 1242 { 1243 int error; 1244 1245 error = relocate_file1(ef, elf_lookup, elf_reloc, false); 1246 if (error == 0) 1247 error = relocate_file1(ef, elf_lookup, elf_reloc, true); 1248 return (error); 1249 } 1250 1251 /* 1252 * Hash function for symbol table lookup. Don't even think about changing 1253 * this. It is specified by the System V ABI. 1254 */ 1255 static unsigned long 1256 elf_hash(const char *name) 1257 { 1258 const unsigned char *p = (const unsigned char *) name; 1259 unsigned long h = 0; 1260 unsigned long g; 1261 1262 while (*p != '\0') { 1263 h = (h << 4) + *p++; 1264 if ((g = h & 0xf0000000) != 0) 1265 h ^= g >> 24; 1266 h &= ~g; 1267 } 1268 return (h); 1269 } 1270 1271 static int 1272 link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym) 1273 { 1274 elf_file_t ef = (elf_file_t) lf; 1275 unsigned long symnum; 1276 const Elf_Sym* symp; 1277 const char *strp; 1278 unsigned long hash; 1279 int i; 1280 1281 /* If we don't have a hash, bail. */ 1282 if (ef->buckets == NULL || ef->nbuckets == 0) { 1283 printf("link_elf_lookup_symbol: missing symbol hash table\n"); 1284 return (ENOENT); 1285 } 1286 1287 /* First, search hashed global symbols */ 1288 hash = elf_hash(name); 1289 symnum = ef->buckets[hash % ef->nbuckets]; 1290 1291 while (symnum != STN_UNDEF) { 1292 if (symnum >= ef->nchains) { 1293 printf("%s: corrupt symbol table\n", __func__); 1294 return (ENOENT); 1295 } 1296 1297 symp = ef->symtab + symnum; 1298 if (symp->st_name == 0) { 1299 printf("%s: corrupt symbol table\n", __func__); 1300 return (ENOENT); 1301 } 1302 1303 strp = ef->strtab + symp->st_name; 1304 1305 if (strcmp(name, strp) == 0) { 1306 if (symp->st_shndx != SHN_UNDEF || 1307 (symp->st_value != 0 && 1308 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1309 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC))) { 1310 *sym = (c_linker_sym_t) symp; 1311 return (0); 1312 } 1313 return (ENOENT); 1314 } 1315 1316 symnum = ef->chains[symnum]; 1317 } 1318 1319 /* If we have not found it, look at the full table (if loaded) */ 1320 if (ef->symtab == ef->ddbsymtab) 1321 return (ENOENT); 1322 1323 /* Exhaustive search */ 1324 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1325 strp = ef->ddbstrtab + symp->st_name; 1326 if (strcmp(name, strp) == 0) { 1327 if (symp->st_shndx != SHN_UNDEF || 1328 (symp->st_value != 0 && 1329 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1330 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC))) { 1331 *sym = (c_linker_sym_t) symp; 1332 return (0); 1333 } 1334 return (ENOENT); 1335 } 1336 } 1337 1338 return (ENOENT); 1339 } 1340 1341 static int 1342 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, 1343 linker_symval_t *symval) 1344 { 1345 elf_file_t ef; 1346 const Elf_Sym *es; 1347 caddr_t val; 1348 1349 ef = (elf_file_t)lf; 1350 es = (const Elf_Sym *)sym; 1351 if (es >= ef->symtab && es < (ef->symtab + ef->nchains)) { 1352 symval->name = ef->strtab + es->st_name; 1353 val = (caddr_t)ef->address + es->st_value; 1354 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC) 1355 val = ((caddr_t (*)(void))val)(); 1356 symval->value = val; 1357 symval->size = es->st_size; 1358 return (0); 1359 } 1360 if (ef->symtab == ef->ddbsymtab) 1361 return (ENOENT); 1362 if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) { 1363 symval->name = ef->ddbstrtab + es->st_name; 1364 val = (caddr_t)ef->address + es->st_value; 1365 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC) 1366 val = ((caddr_t (*)(void))val)(); 1367 symval->value = val; 1368 symval->size = es->st_size; 1369 return (0); 1370 } 1371 return (ENOENT); 1372 } 1373 1374 static int 1375 link_elf_search_symbol(linker_file_t lf, caddr_t value, 1376 c_linker_sym_t *sym, long *diffp) 1377 { 1378 elf_file_t ef = (elf_file_t) lf; 1379 u_long off = (uintptr_t) (void *) value; 1380 u_long diff = off; 1381 u_long st_value; 1382 const Elf_Sym* es; 1383 const Elf_Sym* best = NULL; 1384 int i; 1385 1386 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) { 1387 if (es->st_name == 0) 1388 continue; 1389 st_value = es->st_value + (uintptr_t) (void *) ef->address; 1390 if (off >= st_value) { 1391 if (off - st_value < diff) { 1392 diff = off - st_value; 1393 best = es; 1394 if (diff == 0) 1395 break; 1396 } else if (off - st_value == diff) { 1397 best = es; 1398 } 1399 } 1400 } 1401 if (best == NULL) 1402 *diffp = off; 1403 else 1404 *diffp = diff; 1405 *sym = (c_linker_sym_t) best; 1406 1407 return (0); 1408 } 1409 1410 /* 1411 * Look up a linker set on an ELF system. 1412 */ 1413 static int 1414 link_elf_lookup_set(linker_file_t lf, const char *name, 1415 void ***startp, void ***stopp, int *countp) 1416 { 1417 c_linker_sym_t sym; 1418 linker_symval_t symval; 1419 char *setsym; 1420 void **start, **stop; 1421 int len, error = 0, count; 1422 1423 len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */ 1424 setsym = malloc(len, M_LINKER, M_WAITOK); 1425 1426 /* get address of first entry */ 1427 snprintf(setsym, len, "%s%s", "__start_set_", name); 1428 error = link_elf_lookup_symbol(lf, setsym, &sym); 1429 if (error != 0) 1430 goto out; 1431 link_elf_symbol_values(lf, sym, &symval); 1432 if (symval.value == 0) { 1433 error = ESRCH; 1434 goto out; 1435 } 1436 start = (void **)symval.value; 1437 1438 /* get address of last entry */ 1439 snprintf(setsym, len, "%s%s", "__stop_set_", name); 1440 error = link_elf_lookup_symbol(lf, setsym, &sym); 1441 if (error != 0) 1442 goto out; 1443 link_elf_symbol_values(lf, sym, &symval); 1444 if (symval.value == 0) { 1445 error = ESRCH; 1446 goto out; 1447 } 1448 stop = (void **)symval.value; 1449 1450 /* and the number of entries */ 1451 count = stop - start; 1452 1453 /* and copy out */ 1454 if (startp != NULL) 1455 *startp = start; 1456 if (stopp != NULL) 1457 *stopp = stop; 1458 if (countp != NULL) 1459 *countp = count; 1460 1461 out: 1462 free(setsym, M_LINKER); 1463 return (error); 1464 } 1465 1466 static int 1467 link_elf_each_function_name(linker_file_t file, 1468 int (*callback)(const char *, void *), void *opaque) 1469 { 1470 elf_file_t ef = (elf_file_t)file; 1471 const Elf_Sym *symp; 1472 int i, error; 1473 1474 /* Exhaustive search */ 1475 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1476 if (symp->st_value != 0 && 1477 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1478 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) { 1479 error = callback(ef->ddbstrtab + symp->st_name, opaque); 1480 if (error != 0) 1481 return (error); 1482 } 1483 } 1484 return (0); 1485 } 1486 1487 static int 1488 link_elf_each_function_nameval(linker_file_t file, 1489 linker_function_nameval_callback_t callback, void *opaque) 1490 { 1491 linker_symval_t symval; 1492 elf_file_t ef = (elf_file_t)file; 1493 const Elf_Sym* symp; 1494 int i, error; 1495 1496 /* Exhaustive search */ 1497 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1498 if (symp->st_value != 0 && 1499 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1500 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) { 1501 error = link_elf_symbol_values(file, 1502 (c_linker_sym_t) symp, &symval); 1503 if (error != 0) 1504 return (error); 1505 error = callback(file, i, &symval, opaque); 1506 if (error != 0) 1507 return (error); 1508 } 1509 } 1510 return (0); 1511 } 1512 1513 const Elf_Sym * 1514 elf_get_sym(linker_file_t lf, Elf_Size symidx) 1515 { 1516 elf_file_t ef = (elf_file_t)lf; 1517 1518 if (symidx >= ef->nchains) 1519 return (NULL); 1520 return (ef->symtab + symidx); 1521 } 1522 1523 const char * 1524 elf_get_symname(linker_file_t lf, Elf_Size symidx) 1525 { 1526 elf_file_t ef = (elf_file_t)lf; 1527 const Elf_Sym *sym; 1528 1529 if (symidx >= ef->nchains) 1530 return (NULL); 1531 sym = ef->symtab + symidx; 1532 return (ef->strtab + sym->st_name); 1533 } 1534 1535 /* 1536 * Symbol lookup function that can be used when the symbol index is known (ie 1537 * in relocations). It uses the symbol index instead of doing a fully fledged 1538 * hash table based lookup when such is valid. For example for local symbols. 1539 * This is not only more efficient, it's also more correct. It's not always 1540 * the case that the symbol can be found through the hash table. 1541 */ 1542 static int 1543 elf_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res) 1544 { 1545 elf_file_t ef = (elf_file_t)lf; 1546 const Elf_Sym *sym; 1547 const char *symbol; 1548 Elf_Addr addr, start, base; 1549 1550 /* Don't even try to lookup the symbol if the index is bogus. */ 1551 if (symidx >= ef->nchains) { 1552 *res = 0; 1553 return (EINVAL); 1554 } 1555 1556 sym = ef->symtab + symidx; 1557 1558 /* 1559 * Don't do a full lookup when the symbol is local. It may even 1560 * fail because it may not be found through the hash table. 1561 */ 1562 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) { 1563 /* Force lookup failure when we have an insanity. */ 1564 if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0) { 1565 *res = 0; 1566 return (EINVAL); 1567 } 1568 *res = ((Elf_Addr)ef->address + sym->st_value); 1569 return (0); 1570 } 1571 1572 /* 1573 * XXX we can avoid doing a hash table based lookup for global 1574 * symbols as well. This however is not always valid, so we'll 1575 * just do it the hard way for now. Performance tweaks can 1576 * always be added. 1577 */ 1578 1579 symbol = ef->strtab + sym->st_name; 1580 1581 /* Force a lookup failure if the symbol name is bogus. */ 1582 if (*symbol == 0) { 1583 *res = 0; 1584 return (EINVAL); 1585 } 1586 1587 addr = ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps)); 1588 if (addr == 0 && ELF_ST_BIND(sym->st_info) != STB_WEAK) { 1589 *res = 0; 1590 return (EINVAL); 1591 } 1592 1593 if (elf_set_find(&set_pcpu_list, addr, &start, &base)) 1594 addr = addr - start + base; 1595 #ifdef VIMAGE 1596 else if (elf_set_find(&set_vnet_list, addr, &start, &base)) 1597 addr = addr - start + base; 1598 #endif 1599 *res = addr; 1600 return (0); 1601 } 1602 1603 static void 1604 link_elf_reloc_local(linker_file_t lf) 1605 { 1606 const Elf_Rel *rellim; 1607 const Elf_Rel *rel; 1608 const Elf_Rela *relalim; 1609 const Elf_Rela *rela; 1610 elf_file_t ef = (elf_file_t)lf; 1611 1612 /* Perform relocations without addend if there are any: */ 1613 if ((rel = ef->rel) != NULL) { 1614 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize); 1615 while (rel < rellim) { 1616 elf_reloc_local(lf, (Elf_Addr)ef->address, rel, 1617 ELF_RELOC_REL, elf_lookup); 1618 rel++; 1619 } 1620 } 1621 1622 /* Perform relocations with addend if there are any: */ 1623 if ((rela = ef->rela) != NULL) { 1624 relalim = (const Elf_Rela *) 1625 ((const char *)ef->rela + ef->relasize); 1626 while (rela < relalim) { 1627 elf_reloc_local(lf, (Elf_Addr)ef->address, rela, 1628 ELF_RELOC_RELA, elf_lookup); 1629 rela++; 1630 } 1631 } 1632 } 1633 1634 static long 1635 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab) 1636 { 1637 elf_file_t ef = (elf_file_t)lf; 1638 1639 *symtab = ef->ddbsymtab; 1640 1641 if (*symtab == NULL) 1642 return (0); 1643 1644 return (ef->ddbsymcnt); 1645 } 1646 1647 static long 1648 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab) 1649 { 1650 elf_file_t ef = (elf_file_t)lf; 1651 1652 *strtab = ef->ddbstrtab; 1653 1654 if (*strtab == NULL) 1655 return (0); 1656 1657 return (ef->ddbstrcnt); 1658 } 1659 1660 #if defined(__i386__) || defined(__amd64__) || defined(__aarch64__) 1661 /* 1662 * Use this lookup routine when performing relocations early during boot. 1663 * The generic lookup routine depends on kobj, which is not initialized 1664 * at that point. 1665 */ 1666 static int 1667 elf_lookup_ifunc(linker_file_t lf, Elf_Size symidx, int deps __unused, 1668 Elf_Addr *res) 1669 { 1670 elf_file_t ef; 1671 const Elf_Sym *symp; 1672 caddr_t val; 1673 1674 ef = (elf_file_t)lf; 1675 symp = ef->symtab + symidx; 1676 if (ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC) { 1677 val = (caddr_t)ef->address + symp->st_value; 1678 *res = ((Elf_Addr (*)(void))val)(); 1679 return (0); 1680 } 1681 return (ENOENT); 1682 } 1683 1684 void 1685 link_elf_ireloc(caddr_t kmdp) 1686 { 1687 struct elf_file eff; 1688 elf_file_t ef; 1689 1690 ef = &eff; 1691 1692 bzero_early(ef, sizeof(*ef)); 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