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