Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/kern/link_elf.c
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1 /*- 2 * Copyright (c) 1998-2000 Doug Rabson 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 */ 26 27 #include <sys/cdefs.h> 28 __FBSDID("$FreeBSD: releng/11.2/sys/kern/link_elf.c 333720 2018-05-17 15:24:53Z kib $"); 29 30 #include "opt_ddb.h" 31 #include "opt_gdb.h" 32 33 #include <sys/param.h> 34 #include <sys/systm.h> 35 #ifdef GPROF 36 #include <sys/gmon.h> 37 #endif 38 #include <sys/kernel.h> 39 #include <sys/lock.h> 40 #include <sys/malloc.h> 41 #include <sys/mutex.h> 42 #include <sys/mount.h> 43 #include <sys/pcpu.h> 44 #include <sys/proc.h> 45 #include <sys/namei.h> 46 #include <sys/fcntl.h> 47 #include <sys/vnode.h> 48 #include <sys/linker.h> 49 50 #include <machine/elf.h> 51 52 #include <net/vnet.h> 53 54 #include <security/mac/mac_framework.h> 55 56 #include <vm/vm.h> 57 #include <vm/vm_param.h> 58 #ifdef SPARSE_MAPPING 59 #include <vm/vm_object.h> 60 #include <vm/vm_kern.h> 61 #include <vm/vm_extern.h> 62 #endif 63 #include <vm/pmap.h> 64 #include <vm/vm_map.h> 65 66 #include <sys/link_elf.h> 67 68 #ifdef DDB_CTF 69 #include <sys/zlib.h> 70 #endif 71 72 #include "linker_if.h" 73 74 #define MAXSEGS 4 75 76 typedef struct elf_file { 77 struct linker_file lf; /* Common fields */ 78 int preloaded; /* Was file pre-loaded */ 79 caddr_t address; /* Relocation address */ 80 #ifdef SPARSE_MAPPING 81 vm_object_t object; /* VM object to hold file pages */ 82 #endif 83 Elf_Dyn *dynamic; /* Symbol table etc. */ 84 Elf_Hashelt nbuckets; /* DT_HASH info */ 85 Elf_Hashelt nchains; 86 const Elf_Hashelt *buckets; 87 const Elf_Hashelt *chains; 88 caddr_t hash; 89 caddr_t strtab; /* DT_STRTAB */ 90 int strsz; /* DT_STRSZ */ 91 const Elf_Sym *symtab; /* DT_SYMTAB */ 92 Elf_Addr *got; /* DT_PLTGOT */ 93 const Elf_Rel *pltrel; /* DT_JMPREL */ 94 int pltrelsize; /* DT_PLTRELSZ */ 95 const Elf_Rela *pltrela; /* DT_JMPREL */ 96 int pltrelasize; /* DT_PLTRELSZ */ 97 const Elf_Rel *rel; /* DT_REL */ 98 int relsize; /* DT_RELSZ */ 99 const Elf_Rela *rela; /* DT_RELA */ 100 int relasize; /* DT_RELASZ */ 101 caddr_t modptr; 102 const Elf_Sym *ddbsymtab; /* The symbol table we are using */ 103 long ddbsymcnt; /* Number of symbols */ 104 caddr_t ddbstrtab; /* String table */ 105 long ddbstrcnt; /* number of bytes in string table */ 106 caddr_t symbase; /* malloc'ed symbold base */ 107 caddr_t strbase; /* malloc'ed string base */ 108 caddr_t ctftab; /* CTF table */ 109 long ctfcnt; /* number of bytes in CTF table */ 110 caddr_t ctfoff; /* CTF offset table */ 111 caddr_t typoff; /* Type offset table */ 112 long typlen; /* Number of type entries. */ 113 Elf_Addr pcpu_start; /* Pre-relocation pcpu set start. */ 114 Elf_Addr pcpu_stop; /* Pre-relocation pcpu set stop. */ 115 Elf_Addr pcpu_base; /* Relocated pcpu set address. */ 116 #ifdef VIMAGE 117 Elf_Addr vnet_start; /* Pre-relocation vnet set start. */ 118 Elf_Addr vnet_stop; /* Pre-relocation vnet set stop. */ 119 Elf_Addr vnet_base; /* Relocated vnet set address. */ 120 #endif 121 #ifdef GDB 122 struct link_map gdb; /* hooks for gdb */ 123 #endif 124 } *elf_file_t; 125 126 struct elf_set { 127 Elf_Addr es_start; 128 Elf_Addr es_stop; 129 Elf_Addr es_base; 130 TAILQ_ENTRY(elf_set) es_link; 131 }; 132 133 TAILQ_HEAD(elf_set_head, elf_set); 134 135 #include <kern/kern_ctf.c> 136 137 static int link_elf_link_common_finish(linker_file_t); 138 static int link_elf_link_preload(linker_class_t cls, 139 const char *, linker_file_t *); 140 static int link_elf_link_preload_finish(linker_file_t); 141 static int link_elf_load_file(linker_class_t, const char *, 142 linker_file_t *); 143 static int link_elf_lookup_symbol(linker_file_t, const char *, 144 c_linker_sym_t *); 145 static int link_elf_symbol_values(linker_file_t, c_linker_sym_t, 146 linker_symval_t *); 147 static int link_elf_search_symbol(linker_file_t, caddr_t, 148 c_linker_sym_t *, long *); 149 150 static void link_elf_unload_file(linker_file_t); 151 static void link_elf_unload_preload(linker_file_t); 152 static int link_elf_lookup_set(linker_file_t, const char *, 153 void ***, void ***, int *); 154 static int link_elf_each_function_name(linker_file_t, 155 int (*)(const char *, void *), void *); 156 static int link_elf_each_function_nameval(linker_file_t, 157 linker_function_nameval_callback_t, void *); 158 static void link_elf_reloc_local(linker_file_t); 159 static long link_elf_symtab_get(linker_file_t, const Elf_Sym **); 160 static long link_elf_strtab_get(linker_file_t, caddr_t *); 161 static int elf_lookup(linker_file_t, Elf_Size, int, Elf_Addr *); 162 163 static kobj_method_t link_elf_methods[] = { 164 KOBJMETHOD(linker_lookup_symbol, link_elf_lookup_symbol), 165 KOBJMETHOD(linker_symbol_values, link_elf_symbol_values), 166 KOBJMETHOD(linker_search_symbol, link_elf_search_symbol), 167 KOBJMETHOD(linker_unload, link_elf_unload_file), 168 KOBJMETHOD(linker_load_file, link_elf_load_file), 169 KOBJMETHOD(linker_link_preload, link_elf_link_preload), 170 KOBJMETHOD(linker_link_preload_finish, link_elf_link_preload_finish), 171 KOBJMETHOD(linker_lookup_set, link_elf_lookup_set), 172 KOBJMETHOD(linker_each_function_name, link_elf_each_function_name), 173 KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval), 174 KOBJMETHOD(linker_ctf_get, link_elf_ctf_get), 175 KOBJMETHOD(linker_symtab_get, link_elf_symtab_get), 176 KOBJMETHOD(linker_strtab_get, link_elf_strtab_get), 177 { 0, 0 } 178 }; 179 180 static struct linker_class link_elf_class = { 181 #if ELF_TARG_CLASS == ELFCLASS32 182 "elf32", 183 #else 184 "elf64", 185 #endif 186 link_elf_methods, sizeof(struct elf_file) 187 }; 188 189 static int parse_dynamic(elf_file_t); 190 static int relocate_file(elf_file_t); 191 static int relocate_file1(elf_file_t ef, int (*elf_reloc_func)( 192 linker_file_t lf, Elf_Addr relocbase, const void *data, 193 int type, elf_lookup_fn lookup)); 194 static int link_elf_preload_parse_symbols(elf_file_t); 195 196 static struct elf_set_head set_pcpu_list; 197 #ifdef VIMAGE 198 static struct elf_set_head set_vnet_list; 199 #endif 200 201 static void 202 elf_set_add(struct elf_set_head *list, Elf_Addr start, Elf_Addr stop, Elf_Addr base) 203 { 204 struct elf_set *set, *iter; 205 206 set = malloc(sizeof(*set), M_LINKER, M_WAITOK); 207 set->es_start = start; 208 set->es_stop = stop; 209 set->es_base = base; 210 211 TAILQ_FOREACH(iter, list, es_link) { 212 213 KASSERT((set->es_start < iter->es_start && set->es_stop < iter->es_stop) || 214 (set->es_start > iter->es_start && set->es_stop > iter->es_stop), 215 ("linker sets intersection: to insert: 0x%jx-0x%jx; inserted: 0x%jx-0x%jx", 216 (uintmax_t)set->es_start, (uintmax_t)set->es_stop, 217 (uintmax_t)iter->es_start, (uintmax_t)iter->es_stop)); 218 219 if (iter->es_start > set->es_start) { 220 TAILQ_INSERT_BEFORE(iter, set, es_link); 221 break; 222 } 223 } 224 225 if (iter == NULL) 226 TAILQ_INSERT_TAIL(list, set, es_link); 227 } 228 229 static int 230 elf_set_find(struct elf_set_head *list, Elf_Addr addr, Elf_Addr *start, Elf_Addr *base) 231 { 232 struct elf_set *set; 233 234 TAILQ_FOREACH(set, list, es_link) { 235 if (addr < set->es_start) 236 return (0); 237 if (addr < set->es_stop) { 238 *start = set->es_start; 239 *base = set->es_base; 240 return (1); 241 } 242 } 243 244 return (0); 245 } 246 247 static void 248 elf_set_delete(struct elf_set_head *list, Elf_Addr start) 249 { 250 struct elf_set *set; 251 252 TAILQ_FOREACH(set, list, es_link) { 253 if (start < set->es_start) 254 break; 255 if (start == set->es_start) { 256 TAILQ_REMOVE(list, set, es_link); 257 free(set, M_LINKER); 258 return; 259 } 260 } 261 KASSERT(0, ("deleting unknown linker set (start = 0x%jx)", 262 (uintmax_t)start)); 263 } 264 265 #ifdef GDB 266 static void r_debug_state(struct r_debug *, struct link_map *); 267 268 /* 269 * A list of loaded modules for GDB to use for loading symbols. 270 */ 271 struct r_debug r_debug; 272 273 #define GDB_STATE(s) do { \ 274 r_debug.r_state = s; r_debug_state(NULL, NULL); \ 275 } while (0) 276 277 /* 278 * Function for the debugger to set a breakpoint on to gain control. 279 */ 280 static void 281 r_debug_state(struct r_debug *dummy_one __unused, 282 struct link_map *dummy_two __unused) 283 { 284 } 285 286 static void 287 link_elf_add_gdb(struct link_map *l) 288 { 289 struct link_map *prev; 290 291 l->l_next = NULL; 292 293 if (r_debug.r_map == NULL) { 294 /* Add first. */ 295 l->l_prev = NULL; 296 r_debug.r_map = l; 297 } else { 298 /* Append to list. */ 299 for (prev = r_debug.r_map; 300 prev->l_next != NULL; 301 prev = prev->l_next) 302 ; 303 l->l_prev = prev; 304 prev->l_next = l; 305 } 306 } 307 308 static void 309 link_elf_delete_gdb(struct link_map *l) 310 { 311 if (l->l_prev == NULL) { 312 /* Remove first. */ 313 if ((r_debug.r_map = l->l_next) != NULL) 314 l->l_next->l_prev = NULL; 315 } else { 316 /* Remove any but first. */ 317 if ((l->l_prev->l_next = l->l_next) != NULL) 318 l->l_next->l_prev = l->l_prev; 319 } 320 } 321 #endif /* GDB */ 322 323 /* 324 * The kernel symbol table starts here. 325 */ 326 extern struct _dynamic _DYNAMIC; 327 328 static void 329 link_elf_error(const char *filename, const char *s) 330 { 331 if (filename == NULL) 332 printf("kldload: %s\n", s); 333 else 334 printf("kldload: %s: %s\n", filename, s); 335 } 336 337 static void 338 link_elf_invoke_ctors(caddr_t addr, size_t size) 339 { 340 void (**ctor)(void); 341 size_t i, cnt; 342 343 if (addr == NULL || size == 0) 344 return; 345 cnt = size / sizeof(*ctor); 346 ctor = (void *)addr; 347 for (i = 0; i < cnt; i++) { 348 if (ctor[i] != NULL) 349 (*ctor[i])(); 350 } 351 } 352 353 /* 354 * Actions performed after linking/loading both the preloaded kernel and any 355 * modules; whether preloaded or dynamicly loaded. 356 */ 357 static int 358 link_elf_link_common_finish(linker_file_t lf) 359 { 360 #ifdef GDB 361 elf_file_t ef = (elf_file_t)lf; 362 char *newfilename; 363 #endif 364 int error; 365 366 /* Notify MD code that a module is being loaded. */ 367 error = elf_cpu_load_file(lf); 368 if (error != 0) 369 return (error); 370 371 #ifdef GDB 372 GDB_STATE(RT_ADD); 373 ef->gdb.l_addr = lf->address; 374 newfilename = malloc(strlen(lf->filename) + 1, M_LINKER, M_WAITOK); 375 strcpy(newfilename, lf->filename); 376 ef->gdb.l_name = newfilename; 377 ef->gdb.l_ld = ef->dynamic; 378 link_elf_add_gdb(&ef->gdb); 379 GDB_STATE(RT_CONSISTENT); 380 #endif 381 382 /* Invoke .ctors */ 383 link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size); 384 return (0); 385 } 386 387 extern vm_offset_t __startkernel; 388 389 static void 390 link_elf_init(void* arg) 391 { 392 Elf_Dyn *dp; 393 Elf_Addr *ctors_addrp; 394 Elf_Size *ctors_sizep; 395 caddr_t modptr, baseptr, sizeptr; 396 elf_file_t ef; 397 char *modname; 398 399 linker_add_class(&link_elf_class); 400 401 dp = (Elf_Dyn *)&_DYNAMIC; 402 modname = NULL; 403 modptr = preload_search_by_type("elf" __XSTRING(__ELF_WORD_SIZE) " kernel"); 404 if (modptr == NULL) 405 modptr = preload_search_by_type("elf kernel"); 406 modname = (char *)preload_search_info(modptr, MODINFO_NAME); 407 if (modname == NULL) 408 modname = "kernel"; 409 linker_kernel_file = linker_make_file(modname, &link_elf_class); 410 if (linker_kernel_file == NULL) 411 panic("%s: Can't create linker structures for kernel", 412 __func__); 413 414 ef = (elf_file_t) linker_kernel_file; 415 ef->preloaded = 1; 416 #ifdef __powerpc__ 417 ef->address = (caddr_t) (__startkernel - KERNBASE); 418 #else 419 ef->address = 0; 420 #endif 421 #ifdef SPARSE_MAPPING 422 ef->object = 0; 423 #endif 424 ef->dynamic = dp; 425 426 if (dp != NULL) 427 parse_dynamic(ef); 428 linker_kernel_file->address += KERNBASE; 429 linker_kernel_file->size = -(intptr_t)linker_kernel_file->address; 430 431 if (modptr != NULL) { 432 ef->modptr = modptr; 433 baseptr = preload_search_info(modptr, MODINFO_ADDR); 434 if (baseptr != NULL) 435 linker_kernel_file->address = *(caddr_t *)baseptr; 436 sizeptr = preload_search_info(modptr, MODINFO_SIZE); 437 if (sizeptr != NULL) 438 linker_kernel_file->size = *(size_t *)sizeptr; 439 ctors_addrp = (Elf_Addr *)preload_search_info(modptr, 440 MODINFO_METADATA | MODINFOMD_CTORS_ADDR); 441 ctors_sizep = (Elf_Size *)preload_search_info(modptr, 442 MODINFO_METADATA | MODINFOMD_CTORS_SIZE); 443 if (ctors_addrp != NULL && ctors_sizep != NULL) { 444 linker_kernel_file->ctors_addr = ef->address + 445 *ctors_addrp; 446 linker_kernel_file->ctors_size = *ctors_sizep; 447 } 448 } 449 (void)link_elf_preload_parse_symbols(ef); 450 451 #ifdef GDB 452 r_debug.r_map = NULL; 453 r_debug.r_brk = r_debug_state; 454 r_debug.r_state = RT_CONSISTENT; 455 #endif 456 457 (void)link_elf_link_common_finish(linker_kernel_file); 458 linker_kernel_file->flags |= LINKER_FILE_LINKED; 459 TAILQ_INIT(&set_pcpu_list); 460 #ifdef VIMAGE 461 TAILQ_INIT(&set_vnet_list); 462 #endif 463 } 464 465 SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_THIRD, link_elf_init, 0); 466 467 static int 468 link_elf_preload_parse_symbols(elf_file_t ef) 469 { 470 caddr_t pointer; 471 caddr_t ssym, esym, base; 472 caddr_t strtab; 473 int strcnt; 474 Elf_Sym *symtab; 475 int symcnt; 476 477 if (ef->modptr == NULL) 478 return (0); 479 pointer = preload_search_info(ef->modptr, 480 MODINFO_METADATA | MODINFOMD_SSYM); 481 if (pointer == NULL) 482 return (0); 483 ssym = *(caddr_t *)pointer; 484 pointer = preload_search_info(ef->modptr, 485 MODINFO_METADATA | MODINFOMD_ESYM); 486 if (pointer == NULL) 487 return (0); 488 esym = *(caddr_t *)pointer; 489 490 base = ssym; 491 492 symcnt = *(long *)base; 493 base += sizeof(long); 494 symtab = (Elf_Sym *)base; 495 base += roundup(symcnt, sizeof(long)); 496 497 if (base > esym || base < ssym) { 498 printf("Symbols are corrupt!\n"); 499 return (EINVAL); 500 } 501 502 strcnt = *(long *)base; 503 base += sizeof(long); 504 strtab = base; 505 base += roundup(strcnt, sizeof(long)); 506 507 if (base > esym || base < ssym) { 508 printf("Symbols are corrupt!\n"); 509 return (EINVAL); 510 } 511 512 ef->ddbsymtab = symtab; 513 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym); 514 ef->ddbstrtab = strtab; 515 ef->ddbstrcnt = strcnt; 516 517 return (0); 518 } 519 520 static int 521 parse_dynamic(elf_file_t ef) 522 { 523 Elf_Dyn *dp; 524 int plttype = DT_REL; 525 526 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) { 527 switch (dp->d_tag) { 528 case DT_HASH: 529 { 530 /* From src/libexec/rtld-elf/rtld.c */ 531 const Elf_Hashelt *hashtab = (const Elf_Hashelt *) 532 (ef->address + dp->d_un.d_ptr); 533 ef->nbuckets = hashtab[0]; 534 ef->nchains = hashtab[1]; 535 ef->buckets = hashtab + 2; 536 ef->chains = ef->buckets + ef->nbuckets; 537 break; 538 } 539 case DT_STRTAB: 540 ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr); 541 break; 542 case DT_STRSZ: 543 ef->strsz = dp->d_un.d_val; 544 break; 545 case DT_SYMTAB: 546 ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr); 547 break; 548 case DT_SYMENT: 549 if (dp->d_un.d_val != sizeof(Elf_Sym)) 550 return (ENOEXEC); 551 break; 552 case DT_PLTGOT: 553 ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr); 554 break; 555 case DT_REL: 556 ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr); 557 break; 558 case DT_RELSZ: 559 ef->relsize = dp->d_un.d_val; 560 break; 561 case DT_RELENT: 562 if (dp->d_un.d_val != sizeof(Elf_Rel)) 563 return (ENOEXEC); 564 break; 565 case DT_JMPREL: 566 ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr); 567 break; 568 case DT_PLTRELSZ: 569 ef->pltrelsize = dp->d_un.d_val; 570 break; 571 case DT_RELA: 572 ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr); 573 break; 574 case DT_RELASZ: 575 ef->relasize = dp->d_un.d_val; 576 break; 577 case DT_RELAENT: 578 if (dp->d_un.d_val != sizeof(Elf_Rela)) 579 return (ENOEXEC); 580 break; 581 case DT_PLTREL: 582 plttype = dp->d_un.d_val; 583 if (plttype != DT_REL && plttype != DT_RELA) 584 return (ENOEXEC); 585 break; 586 #ifdef GDB 587 case DT_DEBUG: 588 dp->d_un.d_ptr = (Elf_Addr)&r_debug; 589 break; 590 #endif 591 } 592 } 593 594 if (plttype == DT_RELA) { 595 ef->pltrela = (const Elf_Rela *)ef->pltrel; 596 ef->pltrel = NULL; 597 ef->pltrelasize = ef->pltrelsize; 598 ef->pltrelsize = 0; 599 } 600 601 ef->ddbsymtab = ef->symtab; 602 ef->ddbsymcnt = ef->nchains; 603 ef->ddbstrtab = ef->strtab; 604 ef->ddbstrcnt = ef->strsz; 605 606 return (0); 607 } 608 609 static int 610 parse_dpcpu(elf_file_t ef) 611 { 612 int count; 613 int error; 614 615 ef->pcpu_start = 0; 616 ef->pcpu_stop = 0; 617 error = link_elf_lookup_set(&ef->lf, "pcpu", (void ***)&ef->pcpu_start, 618 (void ***)&ef->pcpu_stop, &count); 619 /* Error just means there is no pcpu set to relocate. */ 620 if (error != 0) 621 return (0); 622 count *= sizeof(void *); 623 /* 624 * Allocate space in the primary pcpu area. Copy in our 625 * initialization from the data section and then initialize 626 * all per-cpu storage from that. 627 */ 628 ef->pcpu_base = (Elf_Addr)(uintptr_t)dpcpu_alloc(count); 629 if (ef->pcpu_base == 0) 630 return (ENOSPC); 631 memcpy((void *)ef->pcpu_base, (void *)ef->pcpu_start, count); 632 dpcpu_copy((void *)ef->pcpu_base, count); 633 elf_set_add(&set_pcpu_list, ef->pcpu_start, ef->pcpu_stop, 634 ef->pcpu_base); 635 636 return (0); 637 } 638 639 #ifdef VIMAGE 640 static int 641 parse_vnet(elf_file_t ef) 642 { 643 int count; 644 int error; 645 646 ef->vnet_start = 0; 647 ef->vnet_stop = 0; 648 error = link_elf_lookup_set(&ef->lf, "vnet", (void ***)&ef->vnet_start, 649 (void ***)&ef->vnet_stop, &count); 650 /* Error just means there is no vnet data set to relocate. */ 651 if (error != 0) 652 return (0); 653 count *= sizeof(void *); 654 /* 655 * Allocate space in the primary vnet area. Copy in our 656 * initialization from the data section and then initialize 657 * all per-vnet storage from that. 658 */ 659 ef->vnet_base = (Elf_Addr)(uintptr_t)vnet_data_alloc(count); 660 if (ef->vnet_base == 0) 661 return (ENOSPC); 662 memcpy((void *)ef->vnet_base, (void *)ef->vnet_start, count); 663 vnet_data_copy((void *)ef->vnet_base, count); 664 elf_set_add(&set_vnet_list, ef->vnet_start, ef->vnet_stop, 665 ef->vnet_base); 666 667 return (0); 668 } 669 #endif 670 671 static int 672 link_elf_link_preload(linker_class_t cls, 673 const char* filename, linker_file_t *result) 674 { 675 Elf_Addr *ctors_addrp; 676 Elf_Size *ctors_sizep; 677 caddr_t modptr, baseptr, sizeptr, dynptr; 678 char *type; 679 elf_file_t ef; 680 linker_file_t lf; 681 int error; 682 vm_offset_t dp; 683 684 /* Look to see if we have the file preloaded */ 685 modptr = preload_search_by_name(filename); 686 if (modptr == NULL) 687 return (ENOENT); 688 689 type = (char *)preload_search_info(modptr, MODINFO_TYPE); 690 baseptr = preload_search_info(modptr, MODINFO_ADDR); 691 sizeptr = preload_search_info(modptr, MODINFO_SIZE); 692 dynptr = preload_search_info(modptr, 693 MODINFO_METADATA | MODINFOMD_DYNAMIC); 694 if (type == NULL || 695 (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) " module") != 0 && 696 strcmp(type, "elf module") != 0)) 697 return (EFTYPE); 698 if (baseptr == NULL || sizeptr == NULL || dynptr == NULL) 699 return (EINVAL); 700 701 lf = linker_make_file(filename, &link_elf_class); 702 if (lf == NULL) 703 return (ENOMEM); 704 705 ef = (elf_file_t) lf; 706 ef->preloaded = 1; 707 ef->modptr = modptr; 708 ef->address = *(caddr_t *)baseptr; 709 #ifdef SPARSE_MAPPING 710 ef->object = 0; 711 #endif 712 dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr; 713 ef->dynamic = (Elf_Dyn *)dp; 714 lf->address = ef->address; 715 lf->size = *(size_t *)sizeptr; 716 717 ctors_addrp = (Elf_Addr *)preload_search_info(modptr, 718 MODINFO_METADATA | MODINFOMD_CTORS_ADDR); 719 ctors_sizep = (Elf_Size *)preload_search_info(modptr, 720 MODINFO_METADATA | MODINFOMD_CTORS_SIZE); 721 if (ctors_addrp != NULL && ctors_sizep != NULL) { 722 lf->ctors_addr = ef->address + *ctors_addrp; 723 lf->ctors_size = *ctors_sizep; 724 } 725 726 error = parse_dynamic(ef); 727 if (error == 0) 728 error = parse_dpcpu(ef); 729 #ifdef VIMAGE 730 if (error == 0) 731 error = parse_vnet(ef); 732 #endif 733 if (error != 0) { 734 linker_file_unload(lf, LINKER_UNLOAD_FORCE); 735 return (error); 736 } 737 link_elf_reloc_local(lf); 738 *result = lf; 739 return (0); 740 } 741 742 static int 743 link_elf_link_preload_finish(linker_file_t lf) 744 { 745 elf_file_t ef; 746 int error; 747 748 ef = (elf_file_t) lf; 749 error = relocate_file(ef); 750 if (error != 0) 751 return (error); 752 (void)link_elf_preload_parse_symbols(ef); 753 754 return (link_elf_link_common_finish(lf)); 755 } 756 757 static int 758 link_elf_load_file(linker_class_t cls, const char* filename, 759 linker_file_t* result) 760 { 761 struct nameidata nd; 762 struct thread* td = curthread; /* XXX */ 763 Elf_Ehdr *hdr; 764 caddr_t firstpage; 765 int nbytes, i; 766 Elf_Phdr *phdr; 767 Elf_Phdr *phlimit; 768 Elf_Phdr *segs[MAXSEGS]; 769 int nsegs; 770 Elf_Phdr *phdyn; 771 Elf_Phdr *phphdr; 772 caddr_t mapbase; 773 size_t mapsize; 774 Elf_Off base_offset; 775 Elf_Addr base_vaddr; 776 Elf_Addr base_vlimit; 777 int error = 0; 778 ssize_t resid; 779 int flags; 780 elf_file_t ef; 781 linker_file_t lf; 782 Elf_Shdr *shdr; 783 int symtabindex; 784 int symstrindex; 785 int shstrindex; 786 int symcnt; 787 int strcnt; 788 char *shstrs; 789 790 shdr = NULL; 791 lf = NULL; 792 shstrs = NULL; 793 794 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td); 795 flags = FREAD; 796 error = vn_open(&nd, &flags, 0, NULL); 797 if (error != 0) 798 return (error); 799 NDFREE(&nd, NDF_ONLY_PNBUF); 800 if (nd.ni_vp->v_type != VREG) { 801 error = ENOEXEC; 802 firstpage = NULL; 803 goto out; 804 } 805 #ifdef MAC 806 error = mac_kld_check_load(curthread->td_ucred, nd.ni_vp); 807 if (error != 0) { 808 firstpage = NULL; 809 goto out; 810 } 811 #endif 812 813 /* 814 * Read the elf header from the file. 815 */ 816 firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK); 817 hdr = (Elf_Ehdr *)firstpage; 818 error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0, 819 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 820 &resid, td); 821 nbytes = PAGE_SIZE - resid; 822 if (error != 0) 823 goto out; 824 825 if (!IS_ELF(*hdr)) { 826 error = ENOEXEC; 827 goto out; 828 } 829 830 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS || 831 hdr->e_ident[EI_DATA] != ELF_TARG_DATA) { 832 link_elf_error(filename, "Unsupported file layout"); 833 error = ENOEXEC; 834 goto out; 835 } 836 if (hdr->e_ident[EI_VERSION] != EV_CURRENT || 837 hdr->e_version != EV_CURRENT) { 838 link_elf_error(filename, "Unsupported file version"); 839 error = ENOEXEC; 840 goto out; 841 } 842 if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) { 843 error = ENOSYS; 844 goto out; 845 } 846 if (hdr->e_machine != ELF_TARG_MACH) { 847 link_elf_error(filename, "Unsupported machine"); 848 error = ENOEXEC; 849 goto out; 850 } 851 852 /* 853 * We rely on the program header being in the first page. 854 * This is not strictly required by the ABI specification, but 855 * it seems to always true in practice. And, it simplifies 856 * things considerably. 857 */ 858 if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) && 859 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) && 860 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes))) 861 link_elf_error(filename, "Unreadable program headers"); 862 863 /* 864 * Scan the program header entries, and save key information. 865 * 866 * We rely on there being exactly two load segments, text and data, 867 * in that order. 868 */ 869 phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff); 870 phlimit = phdr + hdr->e_phnum; 871 nsegs = 0; 872 phdyn = NULL; 873 phphdr = NULL; 874 while (phdr < phlimit) { 875 switch (phdr->p_type) { 876 case PT_LOAD: 877 if (nsegs == MAXSEGS) { 878 link_elf_error(filename, "Too many sections"); 879 error = ENOEXEC; 880 goto out; 881 } 882 /* 883 * XXX: We just trust they come in right order ?? 884 */ 885 segs[nsegs] = phdr; 886 ++nsegs; 887 break; 888 889 case PT_PHDR: 890 phphdr = phdr; 891 break; 892 893 case PT_DYNAMIC: 894 phdyn = phdr; 895 break; 896 897 case PT_INTERP: 898 error = ENOSYS; 899 goto out; 900 } 901 902 ++phdr; 903 } 904 if (phdyn == NULL) { 905 link_elf_error(filename, "Object is not dynamically-linked"); 906 error = ENOEXEC; 907 goto out; 908 } 909 if (nsegs == 0) { 910 link_elf_error(filename, "No sections"); 911 error = ENOEXEC; 912 goto out; 913 } 914 915 /* 916 * Allocate the entire address space of the object, to stake 917 * out our contiguous region, and to establish the base 918 * address for relocation. 919 */ 920 base_offset = trunc_page(segs[0]->p_offset); 921 base_vaddr = trunc_page(segs[0]->p_vaddr); 922 base_vlimit = round_page(segs[nsegs - 1]->p_vaddr + 923 segs[nsegs - 1]->p_memsz); 924 mapsize = base_vlimit - base_vaddr; 925 926 lf = linker_make_file(filename, &link_elf_class); 927 if (lf == NULL) { 928 error = ENOMEM; 929 goto out; 930 } 931 932 ef = (elf_file_t) lf; 933 #ifdef SPARSE_MAPPING 934 ef->object = vm_object_allocate(OBJT_DEFAULT, mapsize >> PAGE_SHIFT); 935 if (ef->object == NULL) { 936 error = ENOMEM; 937 goto out; 938 } 939 ef->address = (caddr_t) vm_map_min(kernel_map); 940 error = vm_map_find(kernel_map, ef->object, 0, 941 (vm_offset_t *) &ef->address, mapsize, 0, VMFS_OPTIMAL_SPACE, 942 VM_PROT_ALL, VM_PROT_ALL, 0); 943 if (error != 0) { 944 vm_object_deallocate(ef->object); 945 ef->object = 0; 946 goto out; 947 } 948 #else 949 ef->address = malloc(mapsize, M_LINKER, M_WAITOK); 950 #endif 951 mapbase = ef->address; 952 953 /* 954 * Read the text and data sections and zero the bss. 955 */ 956 for (i = 0; i < nsegs; i++) { 957 caddr_t segbase = mapbase + segs[i]->p_vaddr - base_vaddr; 958 error = vn_rdwr(UIO_READ, nd.ni_vp, 959 segbase, segs[i]->p_filesz, segs[i]->p_offset, 960 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 961 &resid, td); 962 if (error != 0) 963 goto out; 964 bzero(segbase + segs[i]->p_filesz, 965 segs[i]->p_memsz - segs[i]->p_filesz); 966 967 #ifdef SPARSE_MAPPING 968 /* 969 * Wire down the pages 970 */ 971 error = vm_map_wire(kernel_map, 972 (vm_offset_t) segbase, 973 (vm_offset_t) segbase + segs[i]->p_memsz, 974 VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES); 975 if (error != KERN_SUCCESS) { 976 error = ENOMEM; 977 goto out; 978 } 979 #endif 980 } 981 982 #ifdef GPROF 983 /* Update profiling information with the new text segment. */ 984 mtx_lock(&Giant); 985 kmupetext((uintfptr_t)(mapbase + segs[0]->p_vaddr - base_vaddr + 986 segs[0]->p_memsz)); 987 mtx_unlock(&Giant); 988 #endif 989 990 ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr); 991 992 lf->address = ef->address; 993 lf->size = mapsize; 994 995 error = parse_dynamic(ef); 996 if (error != 0) 997 goto out; 998 error = parse_dpcpu(ef); 999 if (error != 0) 1000 goto out; 1001 #ifdef VIMAGE 1002 error = parse_vnet(ef); 1003 if (error != 0) 1004 goto out; 1005 #endif 1006 link_elf_reloc_local(lf); 1007 1008 VOP_UNLOCK(nd.ni_vp, 0); 1009 error = linker_load_dependencies(lf); 1010 vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY); 1011 if (error != 0) 1012 goto out; 1013 error = relocate_file(ef); 1014 if (error != 0) 1015 goto out; 1016 1017 /* 1018 * Try and load the symbol table if it's present. (you can 1019 * strip it!) 1020 */ 1021 nbytes = hdr->e_shnum * hdr->e_shentsize; 1022 if (nbytes == 0 || hdr->e_shoff == 0) 1023 goto nosyms; 1024 shdr = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO); 1025 error = vn_rdwr(UIO_READ, nd.ni_vp, 1026 (caddr_t)shdr, nbytes, hdr->e_shoff, 1027 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1028 &resid, td); 1029 if (error != 0) 1030 goto out; 1031 1032 /* Read section string table */ 1033 shstrindex = hdr->e_shstrndx; 1034 if (shstrindex != 0 && shdr[shstrindex].sh_type == SHT_STRTAB && 1035 shdr[shstrindex].sh_size != 0) { 1036 nbytes = shdr[shstrindex].sh_size; 1037 shstrs = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO); 1038 error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)shstrs, nbytes, 1039 shdr[shstrindex].sh_offset, UIO_SYSSPACE, IO_NODELOCKED, 1040 td->td_ucred, NOCRED, &resid, td); 1041 if (error) 1042 goto out; 1043 } 1044 1045 symtabindex = -1; 1046 symstrindex = -1; 1047 for (i = 0; i < hdr->e_shnum; i++) { 1048 if (shdr[i].sh_type == SHT_SYMTAB) { 1049 symtabindex = i; 1050 symstrindex = shdr[i].sh_link; 1051 } else if (shstrs != NULL && shdr[i].sh_name != 0 && 1052 strcmp(shstrs + shdr[i].sh_name, ".ctors") == 0) { 1053 /* Record relocated address and size of .ctors. */ 1054 lf->ctors_addr = mapbase + shdr[i].sh_addr - base_vaddr; 1055 lf->ctors_size = shdr[i].sh_size; 1056 } 1057 } 1058 if (symtabindex < 0 || symstrindex < 0) 1059 goto nosyms; 1060 1061 symcnt = shdr[symtabindex].sh_size; 1062 ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK); 1063 strcnt = shdr[symstrindex].sh_size; 1064 ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK); 1065 1066 error = vn_rdwr(UIO_READ, nd.ni_vp, 1067 ef->symbase, symcnt, shdr[symtabindex].sh_offset, 1068 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1069 &resid, td); 1070 if (error != 0) 1071 goto out; 1072 error = vn_rdwr(UIO_READ, nd.ni_vp, 1073 ef->strbase, strcnt, shdr[symstrindex].sh_offset, 1074 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1075 &resid, td); 1076 if (error != 0) 1077 goto out; 1078 1079 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym); 1080 ef->ddbsymtab = (const Elf_Sym *)ef->symbase; 1081 ef->ddbstrcnt = strcnt; 1082 ef->ddbstrtab = ef->strbase; 1083 1084 nosyms: 1085 error = link_elf_link_common_finish(lf); 1086 if (error != 0) 1087 goto out; 1088 1089 *result = lf; 1090 1091 out: 1092 VOP_UNLOCK(nd.ni_vp, 0); 1093 vn_close(nd.ni_vp, FREAD, td->td_ucred, td); 1094 if (error != 0 && lf != NULL) 1095 linker_file_unload(lf, LINKER_UNLOAD_FORCE); 1096 free(shdr, M_LINKER); 1097 free(firstpage, M_LINKER); 1098 free(shstrs, M_LINKER); 1099 1100 return (error); 1101 } 1102 1103 Elf_Addr 1104 elf_relocaddr(linker_file_t lf, Elf_Addr x) 1105 { 1106 elf_file_t ef; 1107 1108 ef = (elf_file_t)lf; 1109 if (x >= ef->pcpu_start && x < ef->pcpu_stop) 1110 return ((x - ef->pcpu_start) + ef->pcpu_base); 1111 #ifdef VIMAGE 1112 if (x >= ef->vnet_start && x < ef->vnet_stop) 1113 return ((x - ef->vnet_start) + ef->vnet_base); 1114 #endif 1115 return (x); 1116 } 1117 1118 1119 static void 1120 link_elf_unload_file(linker_file_t file) 1121 { 1122 elf_file_t ef = (elf_file_t) file; 1123 1124 if (ef->pcpu_base != 0) { 1125 dpcpu_free((void *)ef->pcpu_base, 1126 ef->pcpu_stop - ef->pcpu_start); 1127 elf_set_delete(&set_pcpu_list, ef->pcpu_start); 1128 } 1129 #ifdef VIMAGE 1130 if (ef->vnet_base != 0) { 1131 vnet_data_free((void *)ef->vnet_base, 1132 ef->vnet_stop - ef->vnet_start); 1133 elf_set_delete(&set_vnet_list, ef->vnet_start); 1134 } 1135 #endif 1136 #ifdef GDB 1137 if (ef->gdb.l_ld != NULL) { 1138 GDB_STATE(RT_DELETE); 1139 free((void *)(uintptr_t)ef->gdb.l_name, M_LINKER); 1140 link_elf_delete_gdb(&ef->gdb); 1141 GDB_STATE(RT_CONSISTENT); 1142 } 1143 #endif 1144 1145 /* Notify MD code that a module is being unloaded. */ 1146 elf_cpu_unload_file(file); 1147 1148 if (ef->preloaded) { 1149 link_elf_unload_preload(file); 1150 return; 1151 } 1152 1153 #ifdef SPARSE_MAPPING 1154 if (ef->object != NULL) { 1155 vm_map_remove(kernel_map, (vm_offset_t) ef->address, 1156 (vm_offset_t) ef->address 1157 + (ef->object->size << PAGE_SHIFT)); 1158 } 1159 #else 1160 free(ef->address, M_LINKER); 1161 #endif 1162 free(ef->symbase, M_LINKER); 1163 free(ef->strbase, M_LINKER); 1164 free(ef->ctftab, M_LINKER); 1165 free(ef->ctfoff, M_LINKER); 1166 free(ef->typoff, M_LINKER); 1167 } 1168 1169 static void 1170 link_elf_unload_preload(linker_file_t file) 1171 { 1172 if (file->filename != NULL) 1173 preload_delete_name(file->filename); 1174 } 1175 1176 static const char * 1177 symbol_name(elf_file_t ef, Elf_Size r_info) 1178 { 1179 const Elf_Sym *ref; 1180 1181 if (ELF_R_SYM(r_info)) { 1182 ref = ef->symtab + ELF_R_SYM(r_info); 1183 return (ef->strtab + ref->st_name); 1184 } 1185 return (NULL); 1186 } 1187 1188 static int 1189 relocate_file1(elf_file_t ef, int (*elf_reloc_func)(linker_file_t lf, 1190 Elf_Addr relocbase, const void *data, int type, elf_lookup_fn lookup)) 1191 { 1192 const Elf_Rel *rellim; 1193 const Elf_Rel *rel; 1194 const Elf_Rela *relalim; 1195 const Elf_Rela *rela; 1196 const char *symname; 1197 1198 /* Perform relocations without addend if there are any: */ 1199 rel = ef->rel; 1200 if (rel != NULL) { 1201 rellim = (const Elf_Rel *) 1202 ((const char *)ef->rel + ef->relsize); 1203 while (rel < rellim) { 1204 if (elf_reloc_func(&ef->lf, (Elf_Addr)ef->address, rel, 1205 ELF_RELOC_REL, elf_lookup)) { 1206 symname = symbol_name(ef, rel->r_info); 1207 printf("link_elf: symbol %s undefined\n", symname); 1208 return (ENOENT); 1209 } 1210 rel++; 1211 } 1212 } 1213 1214 /* Perform relocations with addend if there are any: */ 1215 rela = ef->rela; 1216 if (rela != NULL) { 1217 relalim = (const Elf_Rela *) 1218 ((const char *)ef->rela + ef->relasize); 1219 while (rela < relalim) { 1220 if (elf_reloc_func(&ef->lf, (Elf_Addr)ef->address, rela, 1221 ELF_RELOC_RELA, elf_lookup)) { 1222 symname = symbol_name(ef, rela->r_info); 1223 printf("link_elf: symbol %s undefined\n", 1224 symname); 1225 return (ENOENT); 1226 } 1227 rela++; 1228 } 1229 } 1230 1231 /* Perform PLT relocations without addend if there are any: */ 1232 rel = ef->pltrel; 1233 if (rel != NULL) { 1234 rellim = (const Elf_Rel *) 1235 ((const char *)ef->pltrel + ef->pltrelsize); 1236 while (rel < rellim) { 1237 if (elf_reloc_func(&ef->lf, (Elf_Addr)ef->address, rel, 1238 ELF_RELOC_REL, elf_lookup)) { 1239 symname = symbol_name(ef, rel->r_info); 1240 printf("link_elf: symbol %s undefined\n", 1241 symname); 1242 return (ENOENT); 1243 } 1244 rel++; 1245 } 1246 } 1247 1248 /* Perform relocations with addend if there are any: */ 1249 rela = ef->pltrela; 1250 if (rela != NULL) { 1251 relalim = (const Elf_Rela *) 1252 ((const char *)ef->pltrela + ef->pltrelasize); 1253 while (rela < relalim) { 1254 if (elf_reloc_func(&ef->lf, (Elf_Addr)ef->address, rela, 1255 ELF_RELOC_RELA, elf_lookup)) { 1256 symname = symbol_name(ef, rela->r_info); 1257 printf("link_elf: symbol %s undefined\n", 1258 symname); 1259 return (ENOENT); 1260 } 1261 rela++; 1262 } 1263 } 1264 1265 return (0); 1266 } 1267 1268 static int 1269 relocate_file(elf_file_t ef) 1270 { 1271 int e; 1272 1273 e = relocate_file1(ef, elf_reloc); 1274 #if defined(__i386__) || defined(__amd64__) 1275 if (e == 0) 1276 e = relocate_file1(ef, elf_reloc_ifunc); 1277 #endif 1278 return (e); 1279 } 1280 1281 /* 1282 * Hash function for symbol table lookup. Don't even think about changing 1283 * this. It is specified by the System V ABI. 1284 */ 1285 static unsigned long 1286 elf_hash(const char *name) 1287 { 1288 const unsigned char *p = (const unsigned char *) name; 1289 unsigned long h = 0; 1290 unsigned long g; 1291 1292 while (*p != '\0') { 1293 h = (h << 4) + *p++; 1294 if ((g = h & 0xf0000000) != 0) 1295 h ^= g >> 24; 1296 h &= ~g; 1297 } 1298 return (h); 1299 } 1300 1301 static int 1302 link_elf_lookup_symbol(linker_file_t lf, const char* name, c_linker_sym_t* sym) 1303 { 1304 elf_file_t ef = (elf_file_t) lf; 1305 unsigned long symnum; 1306 const Elf_Sym* symp; 1307 const char *strp; 1308 unsigned long hash; 1309 int i; 1310 1311 /* If we don't have a hash, bail. */ 1312 if (ef->buckets == NULL || ef->nbuckets == 0) { 1313 printf("link_elf_lookup_symbol: missing symbol hash table\n"); 1314 return (ENOENT); 1315 } 1316 1317 /* First, search hashed global symbols */ 1318 hash = elf_hash(name); 1319 symnum = ef->buckets[hash % ef->nbuckets]; 1320 1321 while (symnum != STN_UNDEF) { 1322 if (symnum >= ef->nchains) { 1323 printf("%s: corrupt symbol table\n", __func__); 1324 return (ENOENT); 1325 } 1326 1327 symp = ef->symtab + symnum; 1328 if (symp->st_name == 0) { 1329 printf("%s: corrupt symbol table\n", __func__); 1330 return (ENOENT); 1331 } 1332 1333 strp = ef->strtab + symp->st_name; 1334 1335 if (strcmp(name, strp) == 0) { 1336 if (symp->st_shndx != SHN_UNDEF || 1337 (symp->st_value != 0 && 1338 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1339 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC))) { 1340 *sym = (c_linker_sym_t) symp; 1341 return (0); 1342 } 1343 return (ENOENT); 1344 } 1345 1346 symnum = ef->chains[symnum]; 1347 } 1348 1349 /* If we have not found it, look at the full table (if loaded) */ 1350 if (ef->symtab == ef->ddbsymtab) 1351 return (ENOENT); 1352 1353 /* Exhaustive search */ 1354 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1355 strp = ef->ddbstrtab + symp->st_name; 1356 if (strcmp(name, strp) == 0) { 1357 if (symp->st_shndx != SHN_UNDEF || 1358 (symp->st_value != 0 && 1359 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1360 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC))) { 1361 *sym = (c_linker_sym_t) symp; 1362 return (0); 1363 } 1364 return (ENOENT); 1365 } 1366 } 1367 1368 return (ENOENT); 1369 } 1370 1371 static int 1372 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, 1373 linker_symval_t *symval) 1374 { 1375 elf_file_t ef; 1376 const Elf_Sym *es; 1377 caddr_t val; 1378 1379 ef = (elf_file_t)lf; 1380 es = (const Elf_Sym *)sym; 1381 if (es >= ef->symtab && es < (ef->symtab + ef->nchains)) { 1382 symval->name = ef->strtab + es->st_name; 1383 val = (caddr_t)ef->address + es->st_value; 1384 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC) 1385 val = ((caddr_t (*)(void))val)(); 1386 symval->value = val; 1387 symval->size = es->st_size; 1388 return (0); 1389 } 1390 if (ef->symtab == ef->ddbsymtab) 1391 return (ENOENT); 1392 if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) { 1393 symval->name = ef->ddbstrtab + es->st_name; 1394 val = (caddr_t)ef->address + es->st_value; 1395 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC) 1396 val = ((caddr_t (*)(void))val)(); 1397 symval->value = val; 1398 symval->size = es->st_size; 1399 return (0); 1400 } 1401 return (ENOENT); 1402 } 1403 1404 static int 1405 link_elf_search_symbol(linker_file_t lf, caddr_t value, 1406 c_linker_sym_t *sym, long *diffp) 1407 { 1408 elf_file_t ef = (elf_file_t) lf; 1409 u_long off = (uintptr_t) (void *) value; 1410 u_long diff = off; 1411 u_long st_value; 1412 const Elf_Sym* es; 1413 const Elf_Sym* best = NULL; 1414 int i; 1415 1416 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) { 1417 if (es->st_name == 0) 1418 continue; 1419 st_value = es->st_value + (uintptr_t) (void *) ef->address; 1420 if (off >= st_value) { 1421 if (off - st_value < diff) { 1422 diff = off - st_value; 1423 best = es; 1424 if (diff == 0) 1425 break; 1426 } else if (off - st_value == diff) { 1427 best = es; 1428 } 1429 } 1430 } 1431 if (best == NULL) 1432 *diffp = off; 1433 else 1434 *diffp = diff; 1435 *sym = (c_linker_sym_t) best; 1436 1437 return (0); 1438 } 1439 1440 /* 1441 * Look up a linker set on an ELF system. 1442 */ 1443 static int 1444 link_elf_lookup_set(linker_file_t lf, const char *name, 1445 void ***startp, void ***stopp, int *countp) 1446 { 1447 c_linker_sym_t sym; 1448 linker_symval_t symval; 1449 char *setsym; 1450 void **start, **stop; 1451 int len, error = 0, count; 1452 1453 len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */ 1454 setsym = malloc(len, M_LINKER, M_WAITOK); 1455 1456 /* get address of first entry */ 1457 snprintf(setsym, len, "%s%s", "__start_set_", name); 1458 error = link_elf_lookup_symbol(lf, setsym, &sym); 1459 if (error != 0) 1460 goto out; 1461 link_elf_symbol_values(lf, sym, &symval); 1462 if (symval.value == 0) { 1463 error = ESRCH; 1464 goto out; 1465 } 1466 start = (void **)symval.value; 1467 1468 /* get address of last entry */ 1469 snprintf(setsym, len, "%s%s", "__stop_set_", name); 1470 error = link_elf_lookup_symbol(lf, setsym, &sym); 1471 if (error != 0) 1472 goto out; 1473 link_elf_symbol_values(lf, sym, &symval); 1474 if (symval.value == 0) { 1475 error = ESRCH; 1476 goto out; 1477 } 1478 stop = (void **)symval.value; 1479 1480 /* and the number of entries */ 1481 count = stop - start; 1482 1483 /* and copy out */ 1484 if (startp != NULL) 1485 *startp = start; 1486 if (stopp != NULL) 1487 *stopp = stop; 1488 if (countp != NULL) 1489 *countp = count; 1490 1491 out: 1492 free(setsym, M_LINKER); 1493 return (error); 1494 } 1495 1496 static int 1497 link_elf_each_function_name(linker_file_t file, 1498 int (*callback)(const char *, void *), void *opaque) 1499 { 1500 elf_file_t ef = (elf_file_t)file; 1501 const Elf_Sym *symp; 1502 int i, error; 1503 1504 /* Exhaustive search */ 1505 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1506 if (symp->st_value != 0 && 1507 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1508 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) { 1509 error = callback(ef->ddbstrtab + symp->st_name, opaque); 1510 if (error != 0) 1511 return (error); 1512 } 1513 } 1514 return (0); 1515 } 1516 1517 static int 1518 link_elf_each_function_nameval(linker_file_t file, 1519 linker_function_nameval_callback_t callback, void *opaque) 1520 { 1521 linker_symval_t symval; 1522 elf_file_t ef = (elf_file_t)file; 1523 const Elf_Sym* symp; 1524 int i, error; 1525 1526 /* Exhaustive search */ 1527 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1528 if (symp->st_value != 0 && 1529 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1530 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) { 1531 error = link_elf_symbol_values(file, 1532 (c_linker_sym_t) symp, &symval); 1533 if (error != 0) 1534 return (error); 1535 error = callback(file, i, &symval, opaque); 1536 if (error != 0) 1537 return (error); 1538 } 1539 } 1540 return (0); 1541 } 1542 1543 const Elf_Sym * 1544 elf_get_sym(linker_file_t lf, Elf_Size symidx) 1545 { 1546 elf_file_t ef = (elf_file_t)lf; 1547 1548 if (symidx >= ef->nchains) 1549 return (NULL); 1550 return (ef->symtab + symidx); 1551 } 1552 1553 const char * 1554 elf_get_symname(linker_file_t lf, Elf_Size symidx) 1555 { 1556 elf_file_t ef = (elf_file_t)lf; 1557 const Elf_Sym *sym; 1558 1559 if (symidx >= ef->nchains) 1560 return (NULL); 1561 sym = ef->symtab + symidx; 1562 return (ef->strtab + sym->st_name); 1563 } 1564 1565 /* 1566 * Symbol lookup function that can be used when the symbol index is known (ie 1567 * in relocations). It uses the symbol index instead of doing a fully fledged 1568 * hash table based lookup when such is valid. For example for local symbols. 1569 * This is not only more efficient, it's also more correct. It's not always 1570 * the case that the symbol can be found through the hash table. 1571 */ 1572 static int 1573 elf_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res) 1574 { 1575 elf_file_t ef = (elf_file_t)lf; 1576 const Elf_Sym *sym; 1577 const char *symbol; 1578 Elf_Addr addr, start, base; 1579 1580 /* Don't even try to lookup the symbol if the index is bogus. */ 1581 if (symidx >= ef->nchains) { 1582 *res = 0; 1583 return (EINVAL); 1584 } 1585 1586 sym = ef->symtab + symidx; 1587 1588 /* 1589 * Don't do a full lookup when the symbol is local. It may even 1590 * fail because it may not be found through the hash table. 1591 */ 1592 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) { 1593 /* Force lookup failure when we have an insanity. */ 1594 if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0) { 1595 *res = 0; 1596 return (EINVAL); 1597 } 1598 *res = ((Elf_Addr)ef->address + sym->st_value); 1599 return (0); 1600 } 1601 1602 /* 1603 * XXX we can avoid doing a hash table based lookup for global 1604 * symbols as well. This however is not always valid, so we'll 1605 * just do it the hard way for now. Performance tweaks can 1606 * always be added. 1607 */ 1608 1609 symbol = ef->strtab + sym->st_name; 1610 1611 /* Force a lookup failure if the symbol name is bogus. */ 1612 if (*symbol == 0) { 1613 *res = 0; 1614 return (EINVAL); 1615 } 1616 1617 addr = ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps)); 1618 if (addr == 0 && ELF_ST_BIND(sym->st_info) != STB_WEAK) { 1619 *res = 0; 1620 return (EINVAL); 1621 } 1622 1623 if (elf_set_find(&set_pcpu_list, addr, &start, &base)) 1624 addr = addr - start + base; 1625 #ifdef VIMAGE 1626 else if (elf_set_find(&set_vnet_list, addr, &start, &base)) 1627 addr = addr - start + base; 1628 #endif 1629 *res = addr; 1630 return (0); 1631 } 1632 1633 static void 1634 link_elf_reloc_local(linker_file_t lf) 1635 { 1636 const Elf_Rel *rellim; 1637 const Elf_Rel *rel; 1638 const Elf_Rela *relalim; 1639 const Elf_Rela *rela; 1640 elf_file_t ef = (elf_file_t)lf; 1641 1642 /* Perform relocations without addend if there are any: */ 1643 if ((rel = ef->rel) != NULL) { 1644 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize); 1645 while (rel < rellim) { 1646 elf_reloc_local(lf, (Elf_Addr)ef->address, rel, 1647 ELF_RELOC_REL, elf_lookup); 1648 rel++; 1649 } 1650 } 1651 1652 /* Perform relocations with addend if there are any: */ 1653 if ((rela = ef->rela) != NULL) { 1654 relalim = (const Elf_Rela *) 1655 ((const char *)ef->rela + ef->relasize); 1656 while (rela < relalim) { 1657 elf_reloc_local(lf, (Elf_Addr)ef->address, rela, 1658 ELF_RELOC_RELA, elf_lookup); 1659 rela++; 1660 } 1661 } 1662 } 1663 1664 static long 1665 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab) 1666 { 1667 elf_file_t ef = (elf_file_t)lf; 1668 1669 *symtab = ef->ddbsymtab; 1670 1671 if (*symtab == NULL) 1672 return (0); 1673 1674 return (ef->ddbsymcnt); 1675 } 1676 1677 static long 1678 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab) 1679 { 1680 elf_file_t ef = (elf_file_t)lf; 1681 1682 *strtab = ef->ddbstrtab; 1683 1684 if (*strtab == NULL) 1685 return (0); 1686 1687 return (ef->ddbstrcnt); 1688 } 1689 1690 #if defined(__i386__) || defined(__amd64__) 1691 void 1692 link_elf_ireloc(caddr_t kmdp) 1693 { 1694 struct elf_file eff; 1695 elf_file_t ef; 1696 volatile char *c; 1697 size_t i; 1698 1699 ef = &eff; 1700 1701 /* Do not use bzero/memset before ireloc is done. */ 1702 for (c = (char *)ef, i = 0; i < sizeof(*ef); i++) 1703 c[i] = 0; 1704 1705 ef->modptr = kmdp; 1706 ef->dynamic = (Elf_Dyn *)&_DYNAMIC; 1707 parse_dynamic(ef); 1708 ef->address = 0; 1709 link_elf_preload_parse_symbols(ef); 1710 relocate_file1(ef, elf_reloc_ifunc); 1711 } 1712 #endif
Cache object: c82788a649471ab80c56ad919bd61d59
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