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 * 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: releng/12.0/sys/kern/link_elf.c 339953 2018-10-31 14:03:48Z bz $"); 31 32 #include "opt_ddb.h" 33 #include "opt_gdb.h" 34 35 #include <sys/param.h> 36 #include <sys/systm.h> 37 #ifdef GPROF 38 #include <sys/gmon.h> 39 #endif 40 #include <sys/kernel.h> 41 #include <sys/lock.h> 42 #include <sys/malloc.h> 43 #include <sys/mutex.h> 44 #include <sys/mount.h> 45 #include <sys/pcpu.h> 46 #include <sys/proc.h> 47 #include <sys/namei.h> 48 #include <sys/fcntl.h> 49 #include <sys/vnode.h> 50 #include <sys/linker.h> 51 52 #include <machine/elf.h> 53 54 #include <net/vnet.h> 55 56 #include <security/mac/mac_framework.h> 57 58 #include <vm/vm.h> 59 #include <vm/vm_param.h> 60 #ifdef SPARSE_MAPPING 61 #include <vm/vm_object.h> 62 #include <vm/vm_kern.h> 63 #include <vm/vm_extern.h> 64 #endif 65 #include <vm/pmap.h> 66 #include <vm/vm_map.h> 67 68 #include <sys/link_elf.h> 69 70 #ifdef DDB_CTF 71 #include <sys/zlib.h> 72 #endif 73 74 #include "linker_if.h" 75 76 #define MAXSEGS 4 77 78 typedef struct elf_file { 79 struct linker_file lf; /* Common fields */ 80 int preloaded; /* Was file pre-loaded */ 81 caddr_t address; /* Relocation address */ 82 #ifdef SPARSE_MAPPING 83 vm_object_t object; /* VM object to hold file pages */ 84 #endif 85 Elf_Dyn *dynamic; /* Symbol table etc. */ 86 Elf_Hashelt nbuckets; /* DT_HASH info */ 87 Elf_Hashelt nchains; 88 const Elf_Hashelt *buckets; 89 const Elf_Hashelt *chains; 90 caddr_t hash; 91 caddr_t strtab; /* DT_STRTAB */ 92 int strsz; /* DT_STRSZ */ 93 const Elf_Sym *symtab; /* DT_SYMTAB */ 94 Elf_Addr *got; /* DT_PLTGOT */ 95 const Elf_Rel *pltrel; /* DT_JMPREL */ 96 int pltrelsize; /* DT_PLTRELSZ */ 97 const Elf_Rela *pltrela; /* DT_JMPREL */ 98 int pltrelasize; /* DT_PLTRELSZ */ 99 const Elf_Rel *rel; /* DT_REL */ 100 int relsize; /* DT_RELSZ */ 101 const Elf_Rela *rela; /* DT_RELA */ 102 int relasize; /* DT_RELASZ */ 103 caddr_t modptr; 104 const Elf_Sym *ddbsymtab; /* The symbol table we are using */ 105 long ddbsymcnt; /* Number of symbols */ 106 caddr_t ddbstrtab; /* String table */ 107 long ddbstrcnt; /* number of bytes in string table */ 108 caddr_t symbase; /* malloc'ed symbold base */ 109 caddr_t strbase; /* malloc'ed string base */ 110 caddr_t ctftab; /* CTF table */ 111 long ctfcnt; /* number of bytes in CTF table */ 112 caddr_t ctfoff; /* CTF offset table */ 113 caddr_t typoff; /* Type offset table */ 114 long typlen; /* Number of type entries. */ 115 Elf_Addr pcpu_start; /* Pre-relocation pcpu set start. */ 116 Elf_Addr pcpu_stop; /* Pre-relocation pcpu set stop. */ 117 Elf_Addr pcpu_base; /* Relocated pcpu set address. */ 118 #ifdef VIMAGE 119 Elf_Addr vnet_start; /* Pre-relocation vnet set start. */ 120 Elf_Addr vnet_stop; /* Pre-relocation vnet set stop. */ 121 Elf_Addr vnet_base; /* Relocated vnet set address. */ 122 #endif 123 #ifdef GDB 124 struct link_map gdb; /* hooks for gdb */ 125 #endif 126 } *elf_file_t; 127 128 struct elf_set { 129 Elf_Addr es_start; 130 Elf_Addr es_stop; 131 Elf_Addr es_base; 132 TAILQ_ENTRY(elf_set) es_link; 133 }; 134 135 TAILQ_HEAD(elf_set_head, elf_set); 136 137 #include <kern/kern_ctf.c> 138 139 static int link_elf_link_common_finish(linker_file_t); 140 static int link_elf_link_preload(linker_class_t cls, 141 const char *, linker_file_t *); 142 static int link_elf_link_preload_finish(linker_file_t); 143 static int link_elf_load_file(linker_class_t, const char *, 144 linker_file_t *); 145 static int link_elf_lookup_symbol(linker_file_t, const char *, 146 c_linker_sym_t *); 147 static int link_elf_symbol_values(linker_file_t, c_linker_sym_t, 148 linker_symval_t *); 149 static int link_elf_search_symbol(linker_file_t, caddr_t, 150 c_linker_sym_t *, long *); 151 152 static void link_elf_unload_file(linker_file_t); 153 static void link_elf_unload_preload(linker_file_t); 154 static int link_elf_lookup_set(linker_file_t, const char *, 155 void ***, void ***, int *); 156 static int link_elf_each_function_name(linker_file_t, 157 int (*)(const char *, void *), void *); 158 static int link_elf_each_function_nameval(linker_file_t, 159 linker_function_nameval_callback_t, void *); 160 static void link_elf_reloc_local(linker_file_t); 161 static long link_elf_symtab_get(linker_file_t, const Elf_Sym **); 162 static long link_elf_strtab_get(linker_file_t, caddr_t *); 163 static int elf_lookup(linker_file_t, Elf_Size, int, Elf_Addr *); 164 165 static kobj_method_t link_elf_methods[] = { 166 KOBJMETHOD(linker_lookup_symbol, link_elf_lookup_symbol), 167 KOBJMETHOD(linker_symbol_values, link_elf_symbol_values), 168 KOBJMETHOD(linker_search_symbol, link_elf_search_symbol), 169 KOBJMETHOD(linker_unload, link_elf_unload_file), 170 KOBJMETHOD(linker_load_file, link_elf_load_file), 171 KOBJMETHOD(linker_link_preload, link_elf_link_preload), 172 KOBJMETHOD(linker_link_preload_finish, link_elf_link_preload_finish), 173 KOBJMETHOD(linker_lookup_set, link_elf_lookup_set), 174 KOBJMETHOD(linker_each_function_name, link_elf_each_function_name), 175 KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval), 176 KOBJMETHOD(linker_ctf_get, link_elf_ctf_get), 177 KOBJMETHOD(linker_symtab_get, link_elf_symtab_get), 178 KOBJMETHOD(linker_strtab_get, link_elf_strtab_get), 179 { 0, 0 } 180 }; 181 182 static struct linker_class link_elf_class = { 183 #if ELF_TARG_CLASS == ELFCLASS32 184 "elf32", 185 #else 186 "elf64", 187 #endif 188 link_elf_methods, sizeof(struct elf_file) 189 }; 190 191 typedef int (*elf_reloc_fn)(linker_file_t lf, Elf_Addr relocbase, 192 const void *data, int type, elf_lookup_fn lookup); 193 194 static int parse_dynamic(elf_file_t); 195 static int relocate_file(elf_file_t); 196 static int relocate_file1(elf_file_t ef, elf_lookup_fn lookup, 197 elf_reloc_fn reloc, bool ifuncs); 198 static int link_elf_preload_parse_symbols(elf_file_t); 199 200 static struct elf_set_head set_pcpu_list; 201 #ifdef VIMAGE 202 static struct elf_set_head set_vnet_list; 203 #endif 204 205 static void 206 elf_set_add(struct elf_set_head *list, Elf_Addr start, Elf_Addr stop, Elf_Addr base) 207 { 208 struct elf_set *set, *iter; 209 210 set = malloc(sizeof(*set), M_LINKER, M_WAITOK); 211 set->es_start = start; 212 set->es_stop = stop; 213 set->es_base = base; 214 215 TAILQ_FOREACH(iter, list, es_link) { 216 217 KASSERT((set->es_start < iter->es_start && set->es_stop < iter->es_stop) || 218 (set->es_start > iter->es_start && set->es_stop > iter->es_stop), 219 ("linker sets intersection: to insert: 0x%jx-0x%jx; inserted: 0x%jx-0x%jx", 220 (uintmax_t)set->es_start, (uintmax_t)set->es_stop, 221 (uintmax_t)iter->es_start, (uintmax_t)iter->es_stop)); 222 223 if (iter->es_start > set->es_start) { 224 TAILQ_INSERT_BEFORE(iter, set, es_link); 225 break; 226 } 227 } 228 229 if (iter == NULL) 230 TAILQ_INSERT_TAIL(list, set, es_link); 231 } 232 233 static int 234 elf_set_find(struct elf_set_head *list, Elf_Addr addr, Elf_Addr *start, Elf_Addr *base) 235 { 236 struct elf_set *set; 237 238 TAILQ_FOREACH(set, list, es_link) { 239 if (addr < set->es_start) 240 return (0); 241 if (addr < set->es_stop) { 242 *start = set->es_start; 243 *base = set->es_base; 244 return (1); 245 } 246 } 247 248 return (0); 249 } 250 251 static void 252 elf_set_delete(struct elf_set_head *list, Elf_Addr start) 253 { 254 struct elf_set *set; 255 256 TAILQ_FOREACH(set, list, es_link) { 257 if (start < set->es_start) 258 break; 259 if (start == set->es_start) { 260 TAILQ_REMOVE(list, set, es_link); 261 free(set, M_LINKER); 262 return; 263 } 264 } 265 KASSERT(0, ("deleting unknown linker set (start = 0x%jx)", 266 (uintmax_t)start)); 267 } 268 269 #ifdef GDB 270 static void r_debug_state(struct r_debug *, struct link_map *); 271 272 /* 273 * A list of loaded modules for GDB to use for loading symbols. 274 */ 275 struct r_debug r_debug; 276 277 #define GDB_STATE(s) do { \ 278 r_debug.r_state = s; r_debug_state(NULL, NULL); \ 279 } while (0) 280 281 /* 282 * Function for the debugger to set a breakpoint on to gain control. 283 */ 284 static void 285 r_debug_state(struct r_debug *dummy_one __unused, 286 struct link_map *dummy_two __unused) 287 { 288 } 289 290 static void 291 link_elf_add_gdb(struct link_map *l) 292 { 293 struct link_map *prev; 294 295 l->l_next = NULL; 296 297 if (r_debug.r_map == NULL) { 298 /* Add first. */ 299 l->l_prev = NULL; 300 r_debug.r_map = l; 301 } else { 302 /* Append to list. */ 303 for (prev = r_debug.r_map; 304 prev->l_next != NULL; 305 prev = prev->l_next) 306 ; 307 l->l_prev = prev; 308 prev->l_next = l; 309 } 310 } 311 312 static void 313 link_elf_delete_gdb(struct link_map *l) 314 { 315 if (l->l_prev == NULL) { 316 /* Remove first. */ 317 if ((r_debug.r_map = l->l_next) != NULL) 318 l->l_next->l_prev = NULL; 319 } else { 320 /* Remove any but first. */ 321 if ((l->l_prev->l_next = l->l_next) != NULL) 322 l->l_next->l_prev = l->l_prev; 323 } 324 } 325 #endif /* GDB */ 326 327 /* 328 * The kernel symbol table starts here. 329 */ 330 extern struct _dynamic _DYNAMIC; 331 332 static void 333 link_elf_error(const char *filename, const char *s) 334 { 335 if (filename == NULL) 336 printf("kldload: %s\n", s); 337 else 338 printf("kldload: %s: %s\n", filename, s); 339 } 340 341 static void 342 link_elf_invoke_ctors(caddr_t addr, size_t size) 343 { 344 void (**ctor)(void); 345 size_t i, cnt; 346 347 if (addr == NULL || size == 0) 348 return; 349 cnt = size / sizeof(*ctor); 350 ctor = (void *)addr; 351 for (i = 0; i < cnt; i++) { 352 if (ctor[i] != NULL) 353 (*ctor[i])(); 354 } 355 } 356 357 /* 358 * Actions performed after linking/loading both the preloaded kernel and any 359 * modules; whether preloaded or dynamicly loaded. 360 */ 361 static int 362 link_elf_link_common_finish(linker_file_t lf) 363 { 364 #ifdef GDB 365 elf_file_t ef = (elf_file_t)lf; 366 char *newfilename; 367 #endif 368 int error; 369 370 /* Notify MD code that a module is being loaded. */ 371 error = elf_cpu_load_file(lf); 372 if (error != 0) 373 return (error); 374 375 #ifdef GDB 376 GDB_STATE(RT_ADD); 377 ef->gdb.l_addr = lf->address; 378 newfilename = malloc(strlen(lf->filename) + 1, M_LINKER, M_WAITOK); 379 strcpy(newfilename, lf->filename); 380 ef->gdb.l_name = newfilename; 381 ef->gdb.l_ld = ef->dynamic; 382 link_elf_add_gdb(&ef->gdb); 383 GDB_STATE(RT_CONSISTENT); 384 #endif 385 386 /* Invoke .ctors */ 387 link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size); 388 return (0); 389 } 390 391 extern vm_offset_t __startkernel, __endkernel; 392 393 static void 394 link_elf_init(void* arg) 395 { 396 Elf_Dyn *dp; 397 Elf_Addr *ctors_addrp; 398 Elf_Size *ctors_sizep; 399 caddr_t modptr, baseptr, sizeptr; 400 elf_file_t ef; 401 char *modname; 402 403 linker_add_class(&link_elf_class); 404 405 dp = (Elf_Dyn *)&_DYNAMIC; 406 modname = NULL; 407 modptr = preload_search_by_type("elf" __XSTRING(__ELF_WORD_SIZE) " kernel"); 408 if (modptr == NULL) 409 modptr = preload_search_by_type("elf kernel"); 410 modname = (char *)preload_search_info(modptr, MODINFO_NAME); 411 if (modname == NULL) 412 modname = "kernel"; 413 linker_kernel_file = linker_make_file(modname, &link_elf_class); 414 if (linker_kernel_file == NULL) 415 panic("%s: Can't create linker structures for kernel", 416 __func__); 417 418 ef = (elf_file_t) linker_kernel_file; 419 ef->preloaded = 1; 420 #ifdef __powerpc__ 421 ef->address = (caddr_t) (__startkernel - KERNBASE); 422 #else 423 ef->address = 0; 424 #endif 425 #ifdef SPARSE_MAPPING 426 ef->object = 0; 427 #endif 428 ef->dynamic = dp; 429 430 if (dp != NULL) 431 parse_dynamic(ef); 432 #ifdef __powerpc__ 433 linker_kernel_file->address = (caddr_t)__startkernel; 434 linker_kernel_file->size = (intptr_t)(__endkernel - __startkernel); 435 #else 436 linker_kernel_file->address += KERNBASE; 437 linker_kernel_file->size = -(intptr_t)linker_kernel_file->address; 438 #endif 439 440 if (modptr != NULL) { 441 ef->modptr = modptr; 442 baseptr = preload_search_info(modptr, MODINFO_ADDR); 443 if (baseptr != NULL) 444 linker_kernel_file->address = *(caddr_t *)baseptr; 445 sizeptr = preload_search_info(modptr, MODINFO_SIZE); 446 if (sizeptr != NULL) 447 linker_kernel_file->size = *(size_t *)sizeptr; 448 ctors_addrp = (Elf_Addr *)preload_search_info(modptr, 449 MODINFO_METADATA | MODINFOMD_CTORS_ADDR); 450 ctors_sizep = (Elf_Size *)preload_search_info(modptr, 451 MODINFO_METADATA | MODINFOMD_CTORS_SIZE); 452 if (ctors_addrp != NULL && ctors_sizep != NULL) { 453 linker_kernel_file->ctors_addr = ef->address + 454 *ctors_addrp; 455 linker_kernel_file->ctors_size = *ctors_sizep; 456 } 457 } 458 (void)link_elf_preload_parse_symbols(ef); 459 460 #ifdef GDB 461 r_debug.r_map = NULL; 462 r_debug.r_brk = r_debug_state; 463 r_debug.r_state = RT_CONSISTENT; 464 #endif 465 466 (void)link_elf_link_common_finish(linker_kernel_file); 467 linker_kernel_file->flags |= LINKER_FILE_LINKED; 468 TAILQ_INIT(&set_pcpu_list); 469 #ifdef VIMAGE 470 TAILQ_INIT(&set_vnet_list); 471 #endif 472 } 473 474 SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_THIRD, link_elf_init, NULL); 475 476 static int 477 link_elf_preload_parse_symbols(elf_file_t ef) 478 { 479 caddr_t pointer; 480 caddr_t ssym, esym, base; 481 caddr_t strtab; 482 int strcnt; 483 Elf_Sym *symtab; 484 int symcnt; 485 486 if (ef->modptr == NULL) 487 return (0); 488 pointer = preload_search_info(ef->modptr, 489 MODINFO_METADATA | MODINFOMD_SSYM); 490 if (pointer == NULL) 491 return (0); 492 ssym = *(caddr_t *)pointer; 493 pointer = preload_search_info(ef->modptr, 494 MODINFO_METADATA | MODINFOMD_ESYM); 495 if (pointer == NULL) 496 return (0); 497 esym = *(caddr_t *)pointer; 498 499 base = ssym; 500 501 symcnt = *(long *)base; 502 base += sizeof(long); 503 symtab = (Elf_Sym *)base; 504 base += roundup(symcnt, sizeof(long)); 505 506 if (base > esym || base < ssym) { 507 printf("Symbols are corrupt!\n"); 508 return (EINVAL); 509 } 510 511 strcnt = *(long *)base; 512 base += sizeof(long); 513 strtab = base; 514 base += roundup(strcnt, sizeof(long)); 515 516 if (base > esym || base < ssym) { 517 printf("Symbols are corrupt!\n"); 518 return (EINVAL); 519 } 520 521 ef->ddbsymtab = symtab; 522 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym); 523 ef->ddbstrtab = strtab; 524 ef->ddbstrcnt = strcnt; 525 526 return (0); 527 } 528 529 static int 530 parse_dynamic(elf_file_t ef) 531 { 532 Elf_Dyn *dp; 533 int plttype = DT_REL; 534 535 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) { 536 switch (dp->d_tag) { 537 case DT_HASH: 538 { 539 /* From src/libexec/rtld-elf/rtld.c */ 540 const Elf_Hashelt *hashtab = (const Elf_Hashelt *) 541 (ef->address + dp->d_un.d_ptr); 542 ef->nbuckets = hashtab[0]; 543 ef->nchains = hashtab[1]; 544 ef->buckets = hashtab + 2; 545 ef->chains = ef->buckets + ef->nbuckets; 546 break; 547 } 548 case DT_STRTAB: 549 ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr); 550 break; 551 case DT_STRSZ: 552 ef->strsz = dp->d_un.d_val; 553 break; 554 case DT_SYMTAB: 555 ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr); 556 break; 557 case DT_SYMENT: 558 if (dp->d_un.d_val != sizeof(Elf_Sym)) 559 return (ENOEXEC); 560 break; 561 case DT_PLTGOT: 562 ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr); 563 break; 564 case DT_REL: 565 ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr); 566 break; 567 case DT_RELSZ: 568 ef->relsize = dp->d_un.d_val; 569 break; 570 case DT_RELENT: 571 if (dp->d_un.d_val != sizeof(Elf_Rel)) 572 return (ENOEXEC); 573 break; 574 case DT_JMPREL: 575 ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr); 576 break; 577 case DT_PLTRELSZ: 578 ef->pltrelsize = dp->d_un.d_val; 579 break; 580 case DT_RELA: 581 ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr); 582 break; 583 case DT_RELASZ: 584 ef->relasize = dp->d_un.d_val; 585 break; 586 case DT_RELAENT: 587 if (dp->d_un.d_val != sizeof(Elf_Rela)) 588 return (ENOEXEC); 589 break; 590 case DT_PLTREL: 591 plttype = dp->d_un.d_val; 592 if (plttype != DT_REL && plttype != DT_RELA) 593 return (ENOEXEC); 594 break; 595 #ifdef GDB 596 case DT_DEBUG: 597 dp->d_un.d_ptr = (Elf_Addr)&r_debug; 598 break; 599 #endif 600 } 601 } 602 603 if (plttype == DT_RELA) { 604 ef->pltrela = (const Elf_Rela *)ef->pltrel; 605 ef->pltrel = NULL; 606 ef->pltrelasize = ef->pltrelsize; 607 ef->pltrelsize = 0; 608 } 609 610 ef->ddbsymtab = ef->symtab; 611 ef->ddbsymcnt = ef->nchains; 612 ef->ddbstrtab = ef->strtab; 613 ef->ddbstrcnt = ef->strsz; 614 615 return (0); 616 } 617 618 static int 619 parse_dpcpu(elf_file_t ef) 620 { 621 int error, size; 622 623 ef->pcpu_start = 0; 624 ef->pcpu_stop = 0; 625 error = link_elf_lookup_set(&ef->lf, "pcpu", (void ***)&ef->pcpu_start, 626 (void ***)&ef->pcpu_stop, NULL); 627 /* Error just means there is no pcpu set to relocate. */ 628 if (error != 0) 629 return (0); 630 size = (uintptr_t)ef->pcpu_stop - (uintptr_t)ef->pcpu_start; 631 /* Empty set? */ 632 if (size < 1) 633 return (0); 634 /* 635 * Allocate space in the primary pcpu area. Copy in our 636 * initialization from the data section and then initialize 637 * all per-cpu storage from that. 638 */ 639 ef->pcpu_base = (Elf_Addr)(uintptr_t)dpcpu_alloc(size); 640 if (ef->pcpu_base == 0) { 641 printf("%s: pcpu module space is out of space; " 642 "cannot allocate %d for %s\n", 643 __func__, size, ef->lf.pathname); 644 return (ENOSPC); 645 } 646 memcpy((void *)ef->pcpu_base, (void *)ef->pcpu_start, size); 647 dpcpu_copy((void *)ef->pcpu_base, size); 648 elf_set_add(&set_pcpu_list, ef->pcpu_start, ef->pcpu_stop, 649 ef->pcpu_base); 650 651 return (0); 652 } 653 654 #ifdef VIMAGE 655 static int 656 parse_vnet(elf_file_t ef) 657 { 658 int error, size; 659 660 ef->vnet_start = 0; 661 ef->vnet_stop = 0; 662 error = link_elf_lookup_set(&ef->lf, "vnet", (void ***)&ef->vnet_start, 663 (void ***)&ef->vnet_stop, NULL); 664 /* Error just means there is no vnet data set to relocate. */ 665 if (error != 0) 666 return (0); 667 size = (uintptr_t)ef->vnet_stop - (uintptr_t)ef->vnet_start; 668 /* Empty set? */ 669 if (size < 1) 670 return (0); 671 /* 672 * Allocate space in the primary vnet area. Copy in our 673 * initialization from the data section and then initialize 674 * all per-vnet storage from that. 675 */ 676 ef->vnet_base = (Elf_Addr)(uintptr_t)vnet_data_alloc(size); 677 if (ef->vnet_base == 0) { 678 printf("%s: vnet module space is out of space; " 679 "cannot allocate %d for %s\n", 680 __func__, size, ef->lf.pathname); 681 return (ENOSPC); 682 } 683 memcpy((void *)ef->vnet_base, (void *)ef->vnet_start, size); 684 vnet_data_copy((void *)ef->vnet_base, size); 685 elf_set_add(&set_vnet_list, ef->vnet_start, ef->vnet_stop, 686 ef->vnet_base); 687 688 return (0); 689 } 690 #endif 691 692 static int 693 link_elf_link_preload(linker_class_t cls, 694 const char* filename, linker_file_t *result) 695 { 696 Elf_Addr *ctors_addrp; 697 Elf_Size *ctors_sizep; 698 caddr_t modptr, baseptr, sizeptr, dynptr; 699 char *type; 700 elf_file_t ef; 701 linker_file_t lf; 702 int error; 703 vm_offset_t dp; 704 705 /* Look to see if we have the file preloaded */ 706 modptr = preload_search_by_name(filename); 707 if (modptr == NULL) 708 return (ENOENT); 709 710 type = (char *)preload_search_info(modptr, MODINFO_TYPE); 711 baseptr = preload_search_info(modptr, MODINFO_ADDR); 712 sizeptr = preload_search_info(modptr, MODINFO_SIZE); 713 dynptr = preload_search_info(modptr, 714 MODINFO_METADATA | MODINFOMD_DYNAMIC); 715 if (type == NULL || 716 (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) " module") != 0 && 717 strcmp(type, "elf module") != 0)) 718 return (EFTYPE); 719 if (baseptr == NULL || sizeptr == NULL || dynptr == NULL) 720 return (EINVAL); 721 722 lf = linker_make_file(filename, &link_elf_class); 723 if (lf == NULL) 724 return (ENOMEM); 725 726 ef = (elf_file_t) lf; 727 ef->preloaded = 1; 728 ef->modptr = modptr; 729 ef->address = *(caddr_t *)baseptr; 730 #ifdef SPARSE_MAPPING 731 ef->object = 0; 732 #endif 733 dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr; 734 ef->dynamic = (Elf_Dyn *)dp; 735 lf->address = ef->address; 736 lf->size = *(size_t *)sizeptr; 737 738 ctors_addrp = (Elf_Addr *)preload_search_info(modptr, 739 MODINFO_METADATA | MODINFOMD_CTORS_ADDR); 740 ctors_sizep = (Elf_Size *)preload_search_info(modptr, 741 MODINFO_METADATA | MODINFOMD_CTORS_SIZE); 742 if (ctors_addrp != NULL && ctors_sizep != NULL) { 743 lf->ctors_addr = ef->address + *ctors_addrp; 744 lf->ctors_size = *ctors_sizep; 745 } 746 747 error = parse_dynamic(ef); 748 if (error == 0) 749 error = parse_dpcpu(ef); 750 #ifdef VIMAGE 751 if (error == 0) 752 error = parse_vnet(ef); 753 #endif 754 if (error != 0) { 755 linker_file_unload(lf, LINKER_UNLOAD_FORCE); 756 return (error); 757 } 758 link_elf_reloc_local(lf); 759 *result = lf; 760 return (0); 761 } 762 763 static int 764 link_elf_link_preload_finish(linker_file_t lf) 765 { 766 elf_file_t ef; 767 int error; 768 769 ef = (elf_file_t) lf; 770 error = relocate_file(ef); 771 if (error != 0) 772 return (error); 773 (void)link_elf_preload_parse_symbols(ef); 774 775 return (link_elf_link_common_finish(lf)); 776 } 777 778 static int 779 link_elf_load_file(linker_class_t cls, const char* filename, 780 linker_file_t* result) 781 { 782 struct nameidata nd; 783 struct thread* td = curthread; /* XXX */ 784 Elf_Ehdr *hdr; 785 caddr_t firstpage; 786 int nbytes, i; 787 Elf_Phdr *phdr; 788 Elf_Phdr *phlimit; 789 Elf_Phdr *segs[MAXSEGS]; 790 int nsegs; 791 Elf_Phdr *phdyn; 792 caddr_t mapbase; 793 size_t mapsize; 794 Elf_Addr base_vaddr; 795 Elf_Addr base_vlimit; 796 int error = 0; 797 ssize_t resid; 798 int flags; 799 elf_file_t ef; 800 linker_file_t lf; 801 Elf_Shdr *shdr; 802 int symtabindex; 803 int symstrindex; 804 int shstrindex; 805 int symcnt; 806 int strcnt; 807 char *shstrs; 808 809 shdr = NULL; 810 lf = NULL; 811 shstrs = NULL; 812 813 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td); 814 flags = FREAD; 815 error = vn_open(&nd, &flags, 0, NULL); 816 if (error != 0) 817 return (error); 818 NDFREE(&nd, NDF_ONLY_PNBUF); 819 if (nd.ni_vp->v_type != VREG) { 820 error = ENOEXEC; 821 firstpage = NULL; 822 goto out; 823 } 824 #ifdef MAC 825 error = mac_kld_check_load(curthread->td_ucred, nd.ni_vp); 826 if (error != 0) { 827 firstpage = NULL; 828 goto out; 829 } 830 #endif 831 832 /* 833 * Read the elf header from the file. 834 */ 835 firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK); 836 hdr = (Elf_Ehdr *)firstpage; 837 error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0, 838 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 839 &resid, td); 840 nbytes = PAGE_SIZE - resid; 841 if (error != 0) 842 goto out; 843 844 if (!IS_ELF(*hdr)) { 845 error = ENOEXEC; 846 goto out; 847 } 848 849 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS || 850 hdr->e_ident[EI_DATA] != ELF_TARG_DATA) { 851 link_elf_error(filename, "Unsupported file layout"); 852 error = ENOEXEC; 853 goto out; 854 } 855 if (hdr->e_ident[EI_VERSION] != EV_CURRENT || 856 hdr->e_version != EV_CURRENT) { 857 link_elf_error(filename, "Unsupported file version"); 858 error = ENOEXEC; 859 goto out; 860 } 861 if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) { 862 error = ENOSYS; 863 goto out; 864 } 865 if (hdr->e_machine != ELF_TARG_MACH) { 866 link_elf_error(filename, "Unsupported machine"); 867 error = ENOEXEC; 868 goto out; 869 } 870 871 /* 872 * We rely on the program header being in the first page. 873 * This is not strictly required by the ABI specification, but 874 * it seems to always true in practice. And, it simplifies 875 * things considerably. 876 */ 877 if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) && 878 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) && 879 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes))) 880 link_elf_error(filename, "Unreadable program headers"); 881 882 /* 883 * Scan the program header entries, and save key information. 884 * 885 * We rely on there being exactly two load segments, text and data, 886 * in that order. 887 */ 888 phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff); 889 phlimit = phdr + hdr->e_phnum; 890 nsegs = 0; 891 phdyn = NULL; 892 while (phdr < phlimit) { 893 switch (phdr->p_type) { 894 case PT_LOAD: 895 if (nsegs == MAXSEGS) { 896 link_elf_error(filename, "Too many sections"); 897 error = ENOEXEC; 898 goto out; 899 } 900 /* 901 * XXX: We just trust they come in right order ?? 902 */ 903 segs[nsegs] = phdr; 904 ++nsegs; 905 break; 906 907 case PT_DYNAMIC: 908 phdyn = phdr; 909 break; 910 911 case PT_INTERP: 912 error = ENOSYS; 913 goto out; 914 } 915 916 ++phdr; 917 } 918 if (phdyn == NULL) { 919 link_elf_error(filename, "Object is not dynamically-linked"); 920 error = ENOEXEC; 921 goto out; 922 } 923 if (nsegs == 0) { 924 link_elf_error(filename, "No sections"); 925 error = ENOEXEC; 926 goto out; 927 } 928 929 /* 930 * Allocate the entire address space of the object, to stake 931 * out our contiguous region, and to establish the base 932 * address for relocation. 933 */ 934 base_vaddr = trunc_page(segs[0]->p_vaddr); 935 base_vlimit = round_page(segs[nsegs - 1]->p_vaddr + 936 segs[nsegs - 1]->p_memsz); 937 mapsize = base_vlimit - base_vaddr; 938 939 lf = linker_make_file(filename, &link_elf_class); 940 if (lf == NULL) { 941 error = ENOMEM; 942 goto out; 943 } 944 945 ef = (elf_file_t) lf; 946 #ifdef SPARSE_MAPPING 947 ef->object = vm_object_allocate(OBJT_DEFAULT, mapsize >> PAGE_SHIFT); 948 if (ef->object == NULL) { 949 error = ENOMEM; 950 goto out; 951 } 952 ef->address = (caddr_t) vm_map_min(kernel_map); 953 error = vm_map_find(kernel_map, ef->object, 0, 954 (vm_offset_t *) &ef->address, mapsize, 0, VMFS_OPTIMAL_SPACE, 955 VM_PROT_ALL, VM_PROT_ALL, 0); 956 if (error != 0) { 957 vm_object_deallocate(ef->object); 958 ef->object = 0; 959 goto out; 960 } 961 #else 962 ef->address = malloc(mapsize, M_LINKER, M_EXEC | M_WAITOK); 963 #endif 964 mapbase = ef->address; 965 966 /* 967 * Read the text and data sections and zero the bss. 968 */ 969 for (i = 0; i < nsegs; i++) { 970 caddr_t segbase = mapbase + segs[i]->p_vaddr - base_vaddr; 971 error = vn_rdwr(UIO_READ, nd.ni_vp, 972 segbase, segs[i]->p_filesz, segs[i]->p_offset, 973 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 974 &resid, td); 975 if (error != 0) 976 goto out; 977 bzero(segbase + segs[i]->p_filesz, 978 segs[i]->p_memsz - segs[i]->p_filesz); 979 980 #ifdef SPARSE_MAPPING 981 /* 982 * Wire down the pages 983 */ 984 error = vm_map_wire(kernel_map, 985 (vm_offset_t) segbase, 986 (vm_offset_t) segbase + segs[i]->p_memsz, 987 VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES); 988 if (error != KERN_SUCCESS) { 989 error = ENOMEM; 990 goto out; 991 } 992 #endif 993 } 994 995 #ifdef GPROF 996 /* Update profiling information with the new text segment. */ 997 mtx_lock(&Giant); 998 kmupetext((uintfptr_t)(mapbase + segs[0]->p_vaddr - base_vaddr + 999 segs[0]->p_memsz)); 1000 mtx_unlock(&Giant); 1001 #endif 1002 1003 ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr); 1004 1005 lf->address = ef->address; 1006 lf->size = mapsize; 1007 1008 error = parse_dynamic(ef); 1009 if (error != 0) 1010 goto out; 1011 error = parse_dpcpu(ef); 1012 if (error != 0) 1013 goto out; 1014 #ifdef VIMAGE 1015 error = parse_vnet(ef); 1016 if (error != 0) 1017 goto out; 1018 #endif 1019 link_elf_reloc_local(lf); 1020 1021 VOP_UNLOCK(nd.ni_vp, 0); 1022 error = linker_load_dependencies(lf); 1023 vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY); 1024 if (error != 0) 1025 goto out; 1026 error = relocate_file(ef); 1027 if (error != 0) 1028 goto out; 1029 1030 /* 1031 * Try and load the symbol table if it's present. (you can 1032 * strip it!) 1033 */ 1034 nbytes = hdr->e_shnum * hdr->e_shentsize; 1035 if (nbytes == 0 || hdr->e_shoff == 0) 1036 goto nosyms; 1037 shdr = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO); 1038 error = vn_rdwr(UIO_READ, nd.ni_vp, 1039 (caddr_t)shdr, nbytes, hdr->e_shoff, 1040 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1041 &resid, td); 1042 if (error != 0) 1043 goto out; 1044 1045 /* Read section string table */ 1046 shstrindex = hdr->e_shstrndx; 1047 if (shstrindex != 0 && shdr[shstrindex].sh_type == SHT_STRTAB && 1048 shdr[shstrindex].sh_size != 0) { 1049 nbytes = shdr[shstrindex].sh_size; 1050 shstrs = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO); 1051 error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)shstrs, nbytes, 1052 shdr[shstrindex].sh_offset, UIO_SYSSPACE, IO_NODELOCKED, 1053 td->td_ucred, NOCRED, &resid, td); 1054 if (error) 1055 goto out; 1056 } 1057 1058 symtabindex = -1; 1059 symstrindex = -1; 1060 for (i = 0; i < hdr->e_shnum; i++) { 1061 if (shdr[i].sh_type == SHT_SYMTAB) { 1062 symtabindex = i; 1063 symstrindex = shdr[i].sh_link; 1064 } else if (shstrs != NULL && shdr[i].sh_name != 0 && 1065 strcmp(shstrs + shdr[i].sh_name, ".ctors") == 0) { 1066 /* Record relocated address and size of .ctors. */ 1067 lf->ctors_addr = mapbase + shdr[i].sh_addr - base_vaddr; 1068 lf->ctors_size = shdr[i].sh_size; 1069 } 1070 } 1071 if (symtabindex < 0 || symstrindex < 0) 1072 goto nosyms; 1073 1074 symcnt = shdr[symtabindex].sh_size; 1075 ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK); 1076 strcnt = shdr[symstrindex].sh_size; 1077 ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK); 1078 1079 error = vn_rdwr(UIO_READ, nd.ni_vp, 1080 ef->symbase, symcnt, shdr[symtabindex].sh_offset, 1081 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1082 &resid, td); 1083 if (error != 0) 1084 goto out; 1085 error = vn_rdwr(UIO_READ, nd.ni_vp, 1086 ef->strbase, strcnt, shdr[symstrindex].sh_offset, 1087 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1088 &resid, td); 1089 if (error != 0) 1090 goto out; 1091 1092 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym); 1093 ef->ddbsymtab = (const Elf_Sym *)ef->symbase; 1094 ef->ddbstrcnt = strcnt; 1095 ef->ddbstrtab = ef->strbase; 1096 1097 nosyms: 1098 error = link_elf_link_common_finish(lf); 1099 if (error != 0) 1100 goto out; 1101 1102 *result = lf; 1103 1104 out: 1105 VOP_UNLOCK(nd.ni_vp, 0); 1106 vn_close(nd.ni_vp, FREAD, td->td_ucred, td); 1107 if (error != 0 && lf != NULL) 1108 linker_file_unload(lf, LINKER_UNLOAD_FORCE); 1109 free(shdr, M_LINKER); 1110 free(firstpage, M_LINKER); 1111 free(shstrs, M_LINKER); 1112 1113 return (error); 1114 } 1115 1116 Elf_Addr 1117 elf_relocaddr(linker_file_t lf, Elf_Addr x) 1118 { 1119 elf_file_t ef; 1120 1121 ef = (elf_file_t)lf; 1122 if (x >= ef->pcpu_start && x < ef->pcpu_stop) 1123 return ((x - ef->pcpu_start) + ef->pcpu_base); 1124 #ifdef VIMAGE 1125 if (x >= ef->vnet_start && x < ef->vnet_stop) 1126 return ((x - ef->vnet_start) + ef->vnet_base); 1127 #endif 1128 return (x); 1129 } 1130 1131 1132 static void 1133 link_elf_unload_file(linker_file_t file) 1134 { 1135 elf_file_t ef = (elf_file_t) file; 1136 1137 if (ef->pcpu_base != 0) { 1138 dpcpu_free((void *)ef->pcpu_base, 1139 ef->pcpu_stop - ef->pcpu_start); 1140 elf_set_delete(&set_pcpu_list, ef->pcpu_start); 1141 } 1142 #ifdef VIMAGE 1143 if (ef->vnet_base != 0) { 1144 vnet_data_free((void *)ef->vnet_base, 1145 ef->vnet_stop - ef->vnet_start); 1146 elf_set_delete(&set_vnet_list, ef->vnet_start); 1147 } 1148 #endif 1149 #ifdef GDB 1150 if (ef->gdb.l_ld != NULL) { 1151 GDB_STATE(RT_DELETE); 1152 free((void *)(uintptr_t)ef->gdb.l_name, M_LINKER); 1153 link_elf_delete_gdb(&ef->gdb); 1154 GDB_STATE(RT_CONSISTENT); 1155 } 1156 #endif 1157 1158 /* Notify MD code that a module is being unloaded. */ 1159 elf_cpu_unload_file(file); 1160 1161 if (ef->preloaded) { 1162 link_elf_unload_preload(file); 1163 return; 1164 } 1165 1166 #ifdef SPARSE_MAPPING 1167 if (ef->object != NULL) { 1168 vm_map_remove(kernel_map, (vm_offset_t) ef->address, 1169 (vm_offset_t) ef->address 1170 + (ef->object->size << PAGE_SHIFT)); 1171 } 1172 #else 1173 free(ef->address, M_LINKER); 1174 #endif 1175 free(ef->symbase, M_LINKER); 1176 free(ef->strbase, M_LINKER); 1177 free(ef->ctftab, M_LINKER); 1178 free(ef->ctfoff, M_LINKER); 1179 free(ef->typoff, M_LINKER); 1180 } 1181 1182 static void 1183 link_elf_unload_preload(linker_file_t file) 1184 { 1185 if (file->pathname != NULL) 1186 preload_delete_name(file->pathname); 1187 } 1188 1189 static const char * 1190 symbol_name(elf_file_t ef, Elf_Size r_info) 1191 { 1192 const Elf_Sym *ref; 1193 1194 if (ELF_R_SYM(r_info)) { 1195 ref = ef->symtab + ELF_R_SYM(r_info); 1196 return (ef->strtab + ref->st_name); 1197 } 1198 return (NULL); 1199 } 1200 1201 static int 1202 symbol_type(elf_file_t ef, Elf_Size r_info) 1203 { 1204 const Elf_Sym *ref; 1205 1206 if (ELF_R_SYM(r_info)) { 1207 ref = ef->symtab + ELF_R_SYM(r_info); 1208 return (ELF_ST_TYPE(ref->st_info)); 1209 } 1210 return (STT_NOTYPE); 1211 } 1212 1213 static int 1214 relocate_file1(elf_file_t ef, elf_lookup_fn lookup, elf_reloc_fn reloc, 1215 bool ifuncs) 1216 { 1217 const Elf_Rel *rel; 1218 const Elf_Rela *rela; 1219 const char *symname; 1220 1221 #define APPLY_RELOCS(iter, tbl, tblsize, type) do { \ 1222 for ((iter) = (tbl); (iter) != NULL && \ 1223 (iter) < (tbl) + (tblsize) / sizeof(*(iter)); (iter)++) { \ 1224 if ((symbol_type(ef, (iter)->r_info) == \ 1225 STT_GNU_IFUNC || \ 1226 elf_is_ifunc_reloc((iter)->r_info)) != ifuncs) \ 1227 continue; \ 1228 if (reloc(&ef->lf, (Elf_Addr)ef->address, \ 1229 (iter), (type), lookup)) { \ 1230 symname = symbol_name(ef, (iter)->r_info); \ 1231 printf("link_elf: symbol %s undefined\n", \ 1232 symname); \ 1233 return (ENOENT); \ 1234 } \ 1235 } \ 1236 } while (0) 1237 1238 APPLY_RELOCS(rel, ef->rel, ef->relsize, ELF_RELOC_REL); 1239 APPLY_RELOCS(rela, ef->rela, ef->relasize, ELF_RELOC_RELA); 1240 APPLY_RELOCS(rel, ef->pltrel, ef->pltrelsize, ELF_RELOC_REL); 1241 APPLY_RELOCS(rela, ef->pltrela, ef->pltrelasize, ELF_RELOC_RELA); 1242 1243 #undef APPLY_RELOCS 1244 1245 return (0); 1246 } 1247 1248 static int 1249 relocate_file(elf_file_t ef) 1250 { 1251 int error; 1252 1253 error = relocate_file1(ef, elf_lookup, elf_reloc, false); 1254 if (error == 0) 1255 error = relocate_file1(ef, elf_lookup, elf_reloc, true); 1256 return (error); 1257 } 1258 1259 /* 1260 * Hash function for symbol table lookup. Don't even think about changing 1261 * this. It is specified by the System V ABI. 1262 */ 1263 static unsigned long 1264 elf_hash(const char *name) 1265 { 1266 const unsigned char *p = (const unsigned char *) name; 1267 unsigned long h = 0; 1268 unsigned long g; 1269 1270 while (*p != '\0') { 1271 h = (h << 4) + *p++; 1272 if ((g = h & 0xf0000000) != 0) 1273 h ^= g >> 24; 1274 h &= ~g; 1275 } 1276 return (h); 1277 } 1278 1279 static int 1280 link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym) 1281 { 1282 elf_file_t ef = (elf_file_t) lf; 1283 unsigned long symnum; 1284 const Elf_Sym* symp; 1285 const char *strp; 1286 unsigned long hash; 1287 int i; 1288 1289 /* If we don't have a hash, bail. */ 1290 if (ef->buckets == NULL || ef->nbuckets == 0) { 1291 printf("link_elf_lookup_symbol: missing symbol hash table\n"); 1292 return (ENOENT); 1293 } 1294 1295 /* First, search hashed global symbols */ 1296 hash = elf_hash(name); 1297 symnum = ef->buckets[hash % ef->nbuckets]; 1298 1299 while (symnum != STN_UNDEF) { 1300 if (symnum >= ef->nchains) { 1301 printf("%s: corrupt symbol table\n", __func__); 1302 return (ENOENT); 1303 } 1304 1305 symp = ef->symtab + symnum; 1306 if (symp->st_name == 0) { 1307 printf("%s: corrupt symbol table\n", __func__); 1308 return (ENOENT); 1309 } 1310 1311 strp = ef->strtab + symp->st_name; 1312 1313 if (strcmp(name, strp) == 0) { 1314 if (symp->st_shndx != SHN_UNDEF || 1315 (symp->st_value != 0 && 1316 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1317 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC))) { 1318 *sym = (c_linker_sym_t) symp; 1319 return (0); 1320 } 1321 return (ENOENT); 1322 } 1323 1324 symnum = ef->chains[symnum]; 1325 } 1326 1327 /* If we have not found it, look at the full table (if loaded) */ 1328 if (ef->symtab == ef->ddbsymtab) 1329 return (ENOENT); 1330 1331 /* Exhaustive search */ 1332 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1333 strp = ef->ddbstrtab + symp->st_name; 1334 if (strcmp(name, strp) == 0) { 1335 if (symp->st_shndx != SHN_UNDEF || 1336 (symp->st_value != 0 && 1337 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1338 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC))) { 1339 *sym = (c_linker_sym_t) symp; 1340 return (0); 1341 } 1342 return (ENOENT); 1343 } 1344 } 1345 1346 return (ENOENT); 1347 } 1348 1349 static int 1350 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, 1351 linker_symval_t *symval) 1352 { 1353 elf_file_t ef; 1354 const Elf_Sym *es; 1355 caddr_t val; 1356 1357 ef = (elf_file_t)lf; 1358 es = (const Elf_Sym *)sym; 1359 if (es >= ef->symtab && es < (ef->symtab + ef->nchains)) { 1360 symval->name = ef->strtab + es->st_name; 1361 val = (caddr_t)ef->address + es->st_value; 1362 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC) 1363 val = ((caddr_t (*)(void))val)(); 1364 symval->value = val; 1365 symval->size = es->st_size; 1366 return (0); 1367 } 1368 if (ef->symtab == ef->ddbsymtab) 1369 return (ENOENT); 1370 if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) { 1371 symval->name = ef->ddbstrtab + es->st_name; 1372 val = (caddr_t)ef->address + es->st_value; 1373 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC) 1374 val = ((caddr_t (*)(void))val)(); 1375 symval->value = val; 1376 symval->size = es->st_size; 1377 return (0); 1378 } 1379 return (ENOENT); 1380 } 1381 1382 static int 1383 link_elf_search_symbol(linker_file_t lf, caddr_t value, 1384 c_linker_sym_t *sym, long *diffp) 1385 { 1386 elf_file_t ef = (elf_file_t) lf; 1387 u_long off = (uintptr_t) (void *) value; 1388 u_long diff = off; 1389 u_long st_value; 1390 const Elf_Sym* es; 1391 const Elf_Sym* best = NULL; 1392 int i; 1393 1394 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) { 1395 if (es->st_name == 0) 1396 continue; 1397 st_value = es->st_value + (uintptr_t) (void *) ef->address; 1398 if (off >= st_value) { 1399 if (off - st_value < diff) { 1400 diff = off - st_value; 1401 best = es; 1402 if (diff == 0) 1403 break; 1404 } else if (off - st_value == diff) { 1405 best = es; 1406 } 1407 } 1408 } 1409 if (best == NULL) 1410 *diffp = off; 1411 else 1412 *diffp = diff; 1413 *sym = (c_linker_sym_t) best; 1414 1415 return (0); 1416 } 1417 1418 /* 1419 * Look up a linker set on an ELF system. 1420 */ 1421 static int 1422 link_elf_lookup_set(linker_file_t lf, const char *name, 1423 void ***startp, void ***stopp, int *countp) 1424 { 1425 c_linker_sym_t sym; 1426 linker_symval_t symval; 1427 char *setsym; 1428 void **start, **stop; 1429 int len, error = 0, count; 1430 1431 len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */ 1432 setsym = malloc(len, M_LINKER, M_WAITOK); 1433 1434 /* get address of first entry */ 1435 snprintf(setsym, len, "%s%s", "__start_set_", name); 1436 error = link_elf_lookup_symbol(lf, setsym, &sym); 1437 if (error != 0) 1438 goto out; 1439 link_elf_symbol_values(lf, sym, &symval); 1440 if (symval.value == 0) { 1441 error = ESRCH; 1442 goto out; 1443 } 1444 start = (void **)symval.value; 1445 1446 /* get address of last entry */ 1447 snprintf(setsym, len, "%s%s", "__stop_set_", name); 1448 error = link_elf_lookup_symbol(lf, setsym, &sym); 1449 if (error != 0) 1450 goto out; 1451 link_elf_symbol_values(lf, sym, &symval); 1452 if (symval.value == 0) { 1453 error = ESRCH; 1454 goto out; 1455 } 1456 stop = (void **)symval.value; 1457 1458 /* and the number of entries */ 1459 count = stop - start; 1460 1461 /* and copy out */ 1462 if (startp != NULL) 1463 *startp = start; 1464 if (stopp != NULL) 1465 *stopp = stop; 1466 if (countp != NULL) 1467 *countp = count; 1468 1469 out: 1470 free(setsym, M_LINKER); 1471 return (error); 1472 } 1473 1474 static int 1475 link_elf_each_function_name(linker_file_t file, 1476 int (*callback)(const char *, void *), void *opaque) 1477 { 1478 elf_file_t ef = (elf_file_t)file; 1479 const Elf_Sym *symp; 1480 int i, error; 1481 1482 /* Exhaustive search */ 1483 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1484 if (symp->st_value != 0 && 1485 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1486 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) { 1487 error = callback(ef->ddbstrtab + symp->st_name, opaque); 1488 if (error != 0) 1489 return (error); 1490 } 1491 } 1492 return (0); 1493 } 1494 1495 static int 1496 link_elf_each_function_nameval(linker_file_t file, 1497 linker_function_nameval_callback_t callback, void *opaque) 1498 { 1499 linker_symval_t symval; 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 = link_elf_symbol_values(file, 1510 (c_linker_sym_t) symp, &symval); 1511 if (error != 0) 1512 return (error); 1513 error = callback(file, i, &symval, opaque); 1514 if (error != 0) 1515 return (error); 1516 } 1517 } 1518 return (0); 1519 } 1520 1521 const Elf_Sym * 1522 elf_get_sym(linker_file_t lf, Elf_Size symidx) 1523 { 1524 elf_file_t ef = (elf_file_t)lf; 1525 1526 if (symidx >= ef->nchains) 1527 return (NULL); 1528 return (ef->symtab + symidx); 1529 } 1530 1531 const char * 1532 elf_get_symname(linker_file_t lf, Elf_Size symidx) 1533 { 1534 elf_file_t ef = (elf_file_t)lf; 1535 const Elf_Sym *sym; 1536 1537 if (symidx >= ef->nchains) 1538 return (NULL); 1539 sym = ef->symtab + symidx; 1540 return (ef->strtab + sym->st_name); 1541 } 1542 1543 /* 1544 * Symbol lookup function that can be used when the symbol index is known (ie 1545 * in relocations). It uses the symbol index instead of doing a fully fledged 1546 * hash table based lookup when such is valid. For example for local symbols. 1547 * This is not only more efficient, it's also more correct. It's not always 1548 * the case that the symbol can be found through the hash table. 1549 */ 1550 static int 1551 elf_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res) 1552 { 1553 elf_file_t ef = (elf_file_t)lf; 1554 const Elf_Sym *sym; 1555 const char *symbol; 1556 Elf_Addr addr, start, base; 1557 1558 /* Don't even try to lookup the symbol if the index is bogus. */ 1559 if (symidx >= ef->nchains) { 1560 *res = 0; 1561 return (EINVAL); 1562 } 1563 1564 sym = ef->symtab + symidx; 1565 1566 /* 1567 * Don't do a full lookup when the symbol is local. It may even 1568 * fail because it may not be found through the hash table. 1569 */ 1570 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) { 1571 /* Force lookup failure when we have an insanity. */ 1572 if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0) { 1573 *res = 0; 1574 return (EINVAL); 1575 } 1576 *res = ((Elf_Addr)ef->address + sym->st_value); 1577 return (0); 1578 } 1579 1580 /* 1581 * XXX we can avoid doing a hash table based lookup for global 1582 * symbols as well. This however is not always valid, so we'll 1583 * just do it the hard way for now. Performance tweaks can 1584 * always be added. 1585 */ 1586 1587 symbol = ef->strtab + sym->st_name; 1588 1589 /* Force a lookup failure if the symbol name is bogus. */ 1590 if (*symbol == 0) { 1591 *res = 0; 1592 return (EINVAL); 1593 } 1594 1595 addr = ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps)); 1596 if (addr == 0 && ELF_ST_BIND(sym->st_info) != STB_WEAK) { 1597 *res = 0; 1598 return (EINVAL); 1599 } 1600 1601 if (elf_set_find(&set_pcpu_list, addr, &start, &base)) 1602 addr = addr - start + base; 1603 #ifdef VIMAGE 1604 else if (elf_set_find(&set_vnet_list, addr, &start, &base)) 1605 addr = addr - start + base; 1606 #endif 1607 *res = addr; 1608 return (0); 1609 } 1610 1611 static void 1612 link_elf_reloc_local(linker_file_t lf) 1613 { 1614 const Elf_Rel *rellim; 1615 const Elf_Rel *rel; 1616 const Elf_Rela *relalim; 1617 const Elf_Rela *rela; 1618 elf_file_t ef = (elf_file_t)lf; 1619 1620 /* Perform relocations without addend if there are any: */ 1621 if ((rel = ef->rel) != NULL) { 1622 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize); 1623 while (rel < rellim) { 1624 elf_reloc_local(lf, (Elf_Addr)ef->address, rel, 1625 ELF_RELOC_REL, elf_lookup); 1626 rel++; 1627 } 1628 } 1629 1630 /* Perform relocations with addend if there are any: */ 1631 if ((rela = ef->rela) != NULL) { 1632 relalim = (const Elf_Rela *) 1633 ((const char *)ef->rela + ef->relasize); 1634 while (rela < relalim) { 1635 elf_reloc_local(lf, (Elf_Addr)ef->address, rela, 1636 ELF_RELOC_RELA, elf_lookup); 1637 rela++; 1638 } 1639 } 1640 } 1641 1642 static long 1643 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab) 1644 { 1645 elf_file_t ef = (elf_file_t)lf; 1646 1647 *symtab = ef->ddbsymtab; 1648 1649 if (*symtab == NULL) 1650 return (0); 1651 1652 return (ef->ddbsymcnt); 1653 } 1654 1655 static long 1656 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab) 1657 { 1658 elf_file_t ef = (elf_file_t)lf; 1659 1660 *strtab = ef->ddbstrtab; 1661 1662 if (*strtab == NULL) 1663 return (0); 1664 1665 return (ef->ddbstrcnt); 1666 } 1667 1668 #if defined(__i386__) || defined(__amd64__) || defined(__aarch64__) 1669 /* 1670 * Use this lookup routine when performing relocations early during boot. 1671 * The generic lookup routine depends on kobj, which is not initialized 1672 * at that point. 1673 */ 1674 static int 1675 elf_lookup_ifunc(linker_file_t lf, Elf_Size symidx, int deps __unused, 1676 Elf_Addr *res) 1677 { 1678 elf_file_t ef; 1679 const Elf_Sym *symp; 1680 caddr_t val; 1681 1682 ef = (elf_file_t)lf; 1683 symp = ef->symtab + symidx; 1684 if (ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC) { 1685 val = (caddr_t)ef->address + symp->st_value; 1686 *res = ((Elf_Addr (*)(void))val)(); 1687 return (0); 1688 } 1689 return (ENOENT); 1690 } 1691 1692 void 1693 link_elf_ireloc(caddr_t kmdp) 1694 { 1695 struct elf_file eff; 1696 elf_file_t ef; 1697 1698 ef = &eff; 1699 1700 bzero_early(ef, sizeof(*ef)); 1701 1702 ef->modptr = kmdp; 1703 ef->dynamic = (Elf_Dyn *)&_DYNAMIC; 1704 parse_dynamic(ef); 1705 ef->address = 0; 1706 link_elf_preload_parse_symbols(ef); 1707 relocate_file1(ef, elf_lookup_ifunc, elf_reloc, true); 1708 } 1709 #endif
Cache object: faeee1fe8de0f59c1bb8e3302af426cc
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