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("$FreeBSD$"); 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 typedef int (*elf_reloc_fn)(linker_file_t lf, Elf_Addr relocbase, 190 const void *data, int type, elf_lookup_fn lookup); 191 192 static int parse_dynamic(elf_file_t); 193 static int relocate_file(elf_file_t); 194 static int relocate_file1(elf_file_t ef, elf_lookup_fn lookup, 195 elf_reloc_fn reloc, bool ifuncs); 196 static int link_elf_preload_parse_symbols(elf_file_t); 197 198 static struct elf_set_head set_pcpu_list; 199 #ifdef VIMAGE 200 static struct elf_set_head set_vnet_list; 201 #endif 202 203 static void 204 elf_set_add(struct elf_set_head *list, Elf_Addr start, Elf_Addr stop, Elf_Addr base) 205 { 206 struct elf_set *set, *iter; 207 208 set = malloc(sizeof(*set), M_LINKER, M_WAITOK); 209 set->es_start = start; 210 set->es_stop = stop; 211 set->es_base = base; 212 213 TAILQ_FOREACH(iter, list, es_link) { 214 215 KASSERT((set->es_start < iter->es_start && set->es_stop < iter->es_stop) || 216 (set->es_start > iter->es_start && set->es_stop > iter->es_stop), 217 ("linker sets intersection: to insert: 0x%jx-0x%jx; inserted: 0x%jx-0x%jx", 218 (uintmax_t)set->es_start, (uintmax_t)set->es_stop, 219 (uintmax_t)iter->es_start, (uintmax_t)iter->es_stop)); 220 221 if (iter->es_start > set->es_start) { 222 TAILQ_INSERT_BEFORE(iter, set, es_link); 223 break; 224 } 225 } 226 227 if (iter == NULL) 228 TAILQ_INSERT_TAIL(list, set, es_link); 229 } 230 231 static int 232 elf_set_find(struct elf_set_head *list, Elf_Addr addr, Elf_Addr *start, Elf_Addr *base) 233 { 234 struct elf_set *set; 235 236 TAILQ_FOREACH(set, list, es_link) { 237 if (addr < set->es_start) 238 return (0); 239 if (addr < set->es_stop) { 240 *start = set->es_start; 241 *base = set->es_base; 242 return (1); 243 } 244 } 245 246 return (0); 247 } 248 249 static void 250 elf_set_delete(struct elf_set_head *list, Elf_Addr start) 251 { 252 struct elf_set *set; 253 254 TAILQ_FOREACH(set, list, es_link) { 255 if (start < set->es_start) 256 break; 257 if (start == set->es_start) { 258 TAILQ_REMOVE(list, set, es_link); 259 free(set, M_LINKER); 260 return; 261 } 262 } 263 KASSERT(0, ("deleting unknown linker set (start = 0x%jx)", 264 (uintmax_t)start)); 265 } 266 267 #ifdef GDB 268 static void r_debug_state(struct r_debug *, struct link_map *); 269 270 /* 271 * A list of loaded modules for GDB to use for loading symbols. 272 */ 273 struct r_debug r_debug; 274 275 #define GDB_STATE(s) do { \ 276 r_debug.r_state = s; r_debug_state(NULL, NULL); \ 277 } while (0) 278 279 /* 280 * Function for the debugger to set a breakpoint on to gain control. 281 */ 282 static void 283 r_debug_state(struct r_debug *dummy_one __unused, 284 struct link_map *dummy_two __unused) 285 { 286 } 287 288 static void 289 link_elf_add_gdb(struct link_map *l) 290 { 291 struct link_map *prev; 292 293 l->l_next = NULL; 294 295 if (r_debug.r_map == NULL) { 296 /* Add first. */ 297 l->l_prev = NULL; 298 r_debug.r_map = l; 299 } else { 300 /* Append to list. */ 301 for (prev = r_debug.r_map; 302 prev->l_next != NULL; 303 prev = prev->l_next) 304 ; 305 l->l_prev = prev; 306 prev->l_next = l; 307 } 308 } 309 310 static void 311 link_elf_delete_gdb(struct link_map *l) 312 { 313 if (l->l_prev == NULL) { 314 /* Remove first. */ 315 if ((r_debug.r_map = l->l_next) != NULL) 316 l->l_next->l_prev = NULL; 317 } else { 318 /* Remove any but first. */ 319 if ((l->l_prev->l_next = l->l_next) != NULL) 320 l->l_next->l_prev = l->l_prev; 321 } 322 } 323 #endif /* GDB */ 324 325 /* 326 * The kernel symbol table starts here. 327 */ 328 extern struct _dynamic _DYNAMIC; 329 330 static void 331 link_elf_error(const char *filename, const char *s) 332 { 333 if (filename == NULL) 334 printf("kldload: %s\n", s); 335 else 336 printf("kldload: %s: %s\n", filename, s); 337 } 338 339 static void 340 link_elf_invoke_ctors(caddr_t addr, size_t size) 341 { 342 void (**ctor)(void); 343 size_t i, cnt; 344 345 if (addr == NULL || size == 0) 346 return; 347 cnt = size / sizeof(*ctor); 348 ctor = (void *)addr; 349 for (i = 0; i < cnt; i++) { 350 if (ctor[i] != NULL) 351 (*ctor[i])(); 352 } 353 } 354 355 /* 356 * Actions performed after linking/loading both the preloaded kernel and any 357 * modules; whether preloaded or dynamicly loaded. 358 */ 359 static int 360 link_elf_link_common_finish(linker_file_t lf) 361 { 362 #ifdef GDB 363 elf_file_t ef = (elf_file_t)lf; 364 char *newfilename; 365 #endif 366 int error; 367 368 /* Notify MD code that a module is being loaded. */ 369 error = elf_cpu_load_file(lf); 370 if (error != 0) 371 return (error); 372 373 #ifdef GDB 374 GDB_STATE(RT_ADD); 375 ef->gdb.l_addr = lf->address; 376 newfilename = malloc(strlen(lf->filename) + 1, M_LINKER, M_WAITOK); 377 strcpy(newfilename, lf->filename); 378 ef->gdb.l_name = newfilename; 379 ef->gdb.l_ld = ef->dynamic; 380 link_elf_add_gdb(&ef->gdb); 381 GDB_STATE(RT_CONSISTENT); 382 #endif 383 384 /* Invoke .ctors */ 385 link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size); 386 return (0); 387 } 388 389 extern vm_offset_t __startkernel; 390 391 static void 392 link_elf_init(void* arg) 393 { 394 Elf_Dyn *dp; 395 Elf_Addr *ctors_addrp; 396 Elf_Size *ctors_sizep; 397 caddr_t modptr, baseptr, sizeptr; 398 elf_file_t ef; 399 char *modname; 400 401 linker_add_class(&link_elf_class); 402 403 dp = (Elf_Dyn *)&_DYNAMIC; 404 modname = NULL; 405 modptr = preload_search_by_type("elf" __XSTRING(__ELF_WORD_SIZE) " kernel"); 406 if (modptr == NULL) 407 modptr = preload_search_by_type("elf kernel"); 408 modname = (char *)preload_search_info(modptr, MODINFO_NAME); 409 if (modname == NULL) 410 modname = "kernel"; 411 linker_kernel_file = linker_make_file(modname, &link_elf_class); 412 if (linker_kernel_file == NULL) 413 panic("%s: Can't create linker structures for kernel", 414 __func__); 415 416 ef = (elf_file_t) linker_kernel_file; 417 ef->preloaded = 1; 418 #ifdef __powerpc__ 419 ef->address = (caddr_t) (__startkernel - KERNBASE); 420 #else 421 ef->address = 0; 422 #endif 423 #ifdef SPARSE_MAPPING 424 ef->object = 0; 425 #endif 426 ef->dynamic = dp; 427 428 if (dp != NULL) 429 parse_dynamic(ef); 430 linker_kernel_file->address += KERNBASE; 431 linker_kernel_file->size = -(intptr_t)linker_kernel_file->address; 432 433 if (modptr != NULL) { 434 ef->modptr = modptr; 435 baseptr = preload_search_info(modptr, MODINFO_ADDR); 436 if (baseptr != NULL) 437 linker_kernel_file->address = *(caddr_t *)baseptr; 438 sizeptr = preload_search_info(modptr, MODINFO_SIZE); 439 if (sizeptr != NULL) 440 linker_kernel_file->size = *(size_t *)sizeptr; 441 ctors_addrp = (Elf_Addr *)preload_search_info(modptr, 442 MODINFO_METADATA | MODINFOMD_CTORS_ADDR); 443 ctors_sizep = (Elf_Size *)preload_search_info(modptr, 444 MODINFO_METADATA | MODINFOMD_CTORS_SIZE); 445 if (ctors_addrp != NULL && ctors_sizep != NULL) { 446 linker_kernel_file->ctors_addr = ef->address + 447 *ctors_addrp; 448 linker_kernel_file->ctors_size = *ctors_sizep; 449 } 450 } 451 (void)link_elf_preload_parse_symbols(ef); 452 453 #ifdef GDB 454 r_debug.r_map = NULL; 455 r_debug.r_brk = r_debug_state; 456 r_debug.r_state = RT_CONSISTENT; 457 #endif 458 459 (void)link_elf_link_common_finish(linker_kernel_file); 460 linker_kernel_file->flags |= LINKER_FILE_LINKED; 461 TAILQ_INIT(&set_pcpu_list); 462 #ifdef VIMAGE 463 TAILQ_INIT(&set_vnet_list); 464 #endif 465 } 466 467 SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_THIRD, link_elf_init, NULL); 468 469 static int 470 link_elf_preload_parse_symbols(elf_file_t ef) 471 { 472 caddr_t pointer; 473 caddr_t ssym, esym, base; 474 caddr_t strtab; 475 int strcnt; 476 Elf_Sym *symtab; 477 int symcnt; 478 479 if (ef->modptr == NULL) 480 return (0); 481 pointer = preload_search_info(ef->modptr, 482 MODINFO_METADATA | MODINFOMD_SSYM); 483 if (pointer == NULL) 484 return (0); 485 ssym = *(caddr_t *)pointer; 486 pointer = preload_search_info(ef->modptr, 487 MODINFO_METADATA | MODINFOMD_ESYM); 488 if (pointer == NULL) 489 return (0); 490 esym = *(caddr_t *)pointer; 491 492 base = ssym; 493 494 symcnt = *(long *)base; 495 base += sizeof(long); 496 symtab = (Elf_Sym *)base; 497 base += roundup(symcnt, sizeof(long)); 498 499 if (base > esym || base < ssym) { 500 printf("Symbols are corrupt!\n"); 501 return (EINVAL); 502 } 503 504 strcnt = *(long *)base; 505 base += sizeof(long); 506 strtab = base; 507 base += roundup(strcnt, sizeof(long)); 508 509 if (base > esym || base < ssym) { 510 printf("Symbols are corrupt!\n"); 511 return (EINVAL); 512 } 513 514 ef->ddbsymtab = symtab; 515 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym); 516 ef->ddbstrtab = strtab; 517 ef->ddbstrcnt = strcnt; 518 519 return (0); 520 } 521 522 static int 523 parse_dynamic(elf_file_t ef) 524 { 525 Elf_Dyn *dp; 526 int plttype = DT_REL; 527 528 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) { 529 switch (dp->d_tag) { 530 case DT_HASH: 531 { 532 /* From src/libexec/rtld-elf/rtld.c */ 533 const Elf_Hashelt *hashtab = (const Elf_Hashelt *) 534 (ef->address + dp->d_un.d_ptr); 535 ef->nbuckets = hashtab[0]; 536 ef->nchains = hashtab[1]; 537 ef->buckets = hashtab + 2; 538 ef->chains = ef->buckets + ef->nbuckets; 539 break; 540 } 541 case DT_STRTAB: 542 ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr); 543 break; 544 case DT_STRSZ: 545 ef->strsz = dp->d_un.d_val; 546 break; 547 case DT_SYMTAB: 548 ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr); 549 break; 550 case DT_SYMENT: 551 if (dp->d_un.d_val != sizeof(Elf_Sym)) 552 return (ENOEXEC); 553 break; 554 case DT_PLTGOT: 555 ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr); 556 break; 557 case DT_REL: 558 ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr); 559 break; 560 case DT_RELSZ: 561 ef->relsize = dp->d_un.d_val; 562 break; 563 case DT_RELENT: 564 if (dp->d_un.d_val != sizeof(Elf_Rel)) 565 return (ENOEXEC); 566 break; 567 case DT_JMPREL: 568 ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr); 569 break; 570 case DT_PLTRELSZ: 571 ef->pltrelsize = dp->d_un.d_val; 572 break; 573 case DT_RELA: 574 ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr); 575 break; 576 case DT_RELASZ: 577 ef->relasize = dp->d_un.d_val; 578 break; 579 case DT_RELAENT: 580 if (dp->d_un.d_val != sizeof(Elf_Rela)) 581 return (ENOEXEC); 582 break; 583 case DT_PLTREL: 584 plttype = dp->d_un.d_val; 585 if (plttype != DT_REL && plttype != DT_RELA) 586 return (ENOEXEC); 587 break; 588 #ifdef GDB 589 case DT_DEBUG: 590 dp->d_un.d_ptr = (Elf_Addr)&r_debug; 591 break; 592 #endif 593 } 594 } 595 596 if (plttype == DT_RELA) { 597 ef->pltrela = (const Elf_Rela *)ef->pltrel; 598 ef->pltrel = NULL; 599 ef->pltrelasize = ef->pltrelsize; 600 ef->pltrelsize = 0; 601 } 602 603 ef->ddbsymtab = ef->symtab; 604 ef->ddbsymcnt = ef->nchains; 605 ef->ddbstrtab = ef->strtab; 606 ef->ddbstrcnt = ef->strsz; 607 608 return (0); 609 } 610 611 static int 612 parse_dpcpu(elf_file_t ef) 613 { 614 int error, size; 615 616 ef->pcpu_start = 0; 617 ef->pcpu_stop = 0; 618 error = link_elf_lookup_set(&ef->lf, "pcpu", (void ***)&ef->pcpu_start, 619 (void ***)&ef->pcpu_stop, NULL); 620 /* Error just means there is no pcpu set to relocate. */ 621 if (error != 0) 622 return (0); 623 size = (uintptr_t)ef->pcpu_stop - (uintptr_t)ef->pcpu_start; 624 /* Empty set? */ 625 if (size < 1) 626 return (0); 627 /* 628 * Allocate space in the primary pcpu area. Copy in our 629 * initialization from the data section and then initialize 630 * all per-cpu storage from that. 631 */ 632 ef->pcpu_base = (Elf_Addr)(uintptr_t)dpcpu_alloc(size); 633 if (ef->pcpu_base == 0) { 634 printf("%s: pcpu module space is out of space; " 635 "cannot allocate %d for %s\n", 636 __func__, size, ef->lf.pathname); 637 return (ENOSPC); 638 } 639 memcpy((void *)ef->pcpu_base, (void *)ef->pcpu_start, size); 640 dpcpu_copy((void *)ef->pcpu_base, size); 641 elf_set_add(&set_pcpu_list, ef->pcpu_start, ef->pcpu_stop, 642 ef->pcpu_base); 643 644 return (0); 645 } 646 647 #ifdef VIMAGE 648 static int 649 parse_vnet(elf_file_t ef) 650 { 651 int error, size; 652 653 ef->vnet_start = 0; 654 ef->vnet_stop = 0; 655 error = link_elf_lookup_set(&ef->lf, "vnet", (void ***)&ef->vnet_start, 656 (void ***)&ef->vnet_stop, NULL); 657 /* Error just means there is no vnet data set to relocate. */ 658 if (error != 0) 659 return (0); 660 size = (uintptr_t)ef->vnet_stop - (uintptr_t)ef->vnet_start; 661 /* Empty set? */ 662 if (size < 1) 663 return (0); 664 /* 665 * Allocate space in the primary vnet area. Copy in our 666 * initialization from the data section and then initialize 667 * all per-vnet storage from that. 668 */ 669 ef->vnet_base = (Elf_Addr)(uintptr_t)vnet_data_alloc(size); 670 if (ef->vnet_base == 0) { 671 printf("%s: vnet module space is out of space; " 672 "cannot allocate %d for %s\n", 673 __func__, size, ef->lf.pathname); 674 return (ENOSPC); 675 } 676 memcpy((void *)ef->vnet_base, (void *)ef->vnet_start, size); 677 vnet_data_copy((void *)ef->vnet_base, size); 678 elf_set_add(&set_vnet_list, ef->vnet_start, ef->vnet_stop, 679 ef->vnet_base); 680 681 return (0); 682 } 683 #endif 684 685 static int 686 link_elf_link_preload(linker_class_t cls, 687 const char* filename, linker_file_t *result) 688 { 689 Elf_Addr *ctors_addrp; 690 Elf_Size *ctors_sizep; 691 caddr_t modptr, baseptr, sizeptr, dynptr; 692 char *type; 693 elf_file_t ef; 694 linker_file_t lf; 695 int error; 696 vm_offset_t dp; 697 698 /* Look to see if we have the file preloaded */ 699 modptr = preload_search_by_name(filename); 700 if (modptr == NULL) 701 return (ENOENT); 702 703 type = (char *)preload_search_info(modptr, MODINFO_TYPE); 704 baseptr = preload_search_info(modptr, MODINFO_ADDR); 705 sizeptr = preload_search_info(modptr, MODINFO_SIZE); 706 dynptr = preload_search_info(modptr, 707 MODINFO_METADATA | MODINFOMD_DYNAMIC); 708 if (type == NULL || 709 (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) " module") != 0 && 710 strcmp(type, "elf module") != 0)) 711 return (EFTYPE); 712 if (baseptr == NULL || sizeptr == NULL || dynptr == NULL) 713 return (EINVAL); 714 715 lf = linker_make_file(filename, &link_elf_class); 716 if (lf == NULL) 717 return (ENOMEM); 718 719 ef = (elf_file_t) lf; 720 ef->preloaded = 1; 721 ef->modptr = modptr; 722 ef->address = *(caddr_t *)baseptr; 723 #ifdef SPARSE_MAPPING 724 ef->object = 0; 725 #endif 726 dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr; 727 ef->dynamic = (Elf_Dyn *)dp; 728 lf->address = ef->address; 729 lf->size = *(size_t *)sizeptr; 730 731 ctors_addrp = (Elf_Addr *)preload_search_info(modptr, 732 MODINFO_METADATA | MODINFOMD_CTORS_ADDR); 733 ctors_sizep = (Elf_Size *)preload_search_info(modptr, 734 MODINFO_METADATA | MODINFOMD_CTORS_SIZE); 735 if (ctors_addrp != NULL && ctors_sizep != NULL) { 736 lf->ctors_addr = ef->address + *ctors_addrp; 737 lf->ctors_size = *ctors_sizep; 738 } 739 740 error = parse_dynamic(ef); 741 if (error == 0) 742 error = parse_dpcpu(ef); 743 #ifdef VIMAGE 744 if (error == 0) 745 error = parse_vnet(ef); 746 #endif 747 if (error != 0) { 748 linker_file_unload(lf, LINKER_UNLOAD_FORCE); 749 return (error); 750 } 751 link_elf_reloc_local(lf); 752 *result = lf; 753 return (0); 754 } 755 756 static int 757 link_elf_link_preload_finish(linker_file_t lf) 758 { 759 elf_file_t ef; 760 int error; 761 762 ef = (elf_file_t) lf; 763 error = relocate_file(ef); 764 if (error != 0) 765 return (error); 766 (void)link_elf_preload_parse_symbols(ef); 767 768 return (link_elf_link_common_finish(lf)); 769 } 770 771 static int 772 link_elf_load_file(linker_class_t cls, const char* filename, 773 linker_file_t* result) 774 { 775 struct nameidata nd; 776 struct thread* td = curthread; /* XXX */ 777 Elf_Ehdr *hdr; 778 caddr_t firstpage; 779 int nbytes, i; 780 Elf_Phdr *phdr; 781 Elf_Phdr *phlimit; 782 Elf_Phdr *segs[MAXSEGS]; 783 int nsegs; 784 Elf_Phdr *phdyn; 785 Elf_Phdr *phphdr; 786 caddr_t mapbase; 787 size_t mapsize; 788 Elf_Off base_offset; 789 Elf_Addr base_vaddr; 790 Elf_Addr base_vlimit; 791 int error = 0; 792 ssize_t resid; 793 int flags; 794 elf_file_t ef; 795 linker_file_t lf; 796 Elf_Shdr *shdr; 797 int symtabindex; 798 int symstrindex; 799 int shstrindex; 800 int symcnt; 801 int strcnt; 802 char *shstrs; 803 804 shdr = NULL; 805 lf = NULL; 806 shstrs = NULL; 807 808 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td); 809 flags = FREAD; 810 error = vn_open(&nd, &flags, 0, NULL); 811 if (error != 0) 812 return (error); 813 NDFREE(&nd, NDF_ONLY_PNBUF); 814 if (nd.ni_vp->v_type != VREG) { 815 error = ENOEXEC; 816 firstpage = NULL; 817 goto out; 818 } 819 #ifdef MAC 820 error = mac_kld_check_load(curthread->td_ucred, nd.ni_vp); 821 if (error != 0) { 822 firstpage = NULL; 823 goto out; 824 } 825 #endif 826 827 /* 828 * Read the elf header from the file. 829 */ 830 firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK); 831 hdr = (Elf_Ehdr *)firstpage; 832 error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0, 833 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 834 &resid, td); 835 nbytes = PAGE_SIZE - resid; 836 if (error != 0) 837 goto out; 838 839 if (!IS_ELF(*hdr)) { 840 error = ENOEXEC; 841 goto out; 842 } 843 844 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS || 845 hdr->e_ident[EI_DATA] != ELF_TARG_DATA) { 846 link_elf_error(filename, "Unsupported file layout"); 847 error = ENOEXEC; 848 goto out; 849 } 850 if (hdr->e_ident[EI_VERSION] != EV_CURRENT || 851 hdr->e_version != EV_CURRENT) { 852 link_elf_error(filename, "Unsupported file version"); 853 error = ENOEXEC; 854 goto out; 855 } 856 if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) { 857 error = ENOSYS; 858 goto out; 859 } 860 if (hdr->e_machine != ELF_TARG_MACH) { 861 link_elf_error(filename, "Unsupported machine"); 862 error = ENOEXEC; 863 goto out; 864 } 865 866 /* 867 * We rely on the program header being in the first page. 868 * This is not strictly required by the ABI specification, but 869 * it seems to always true in practice. And, it simplifies 870 * things considerably. 871 */ 872 if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) && 873 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) && 874 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes))) 875 link_elf_error(filename, "Unreadable program headers"); 876 877 /* 878 * Scan the program header entries, and save key information. 879 * 880 * We rely on there being exactly two load segments, text and data, 881 * in that order. 882 */ 883 phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff); 884 phlimit = phdr + hdr->e_phnum; 885 nsegs = 0; 886 phdyn = NULL; 887 phphdr = NULL; 888 while (phdr < phlimit) { 889 switch (phdr->p_type) { 890 case PT_LOAD: 891 if (nsegs == MAXSEGS) { 892 link_elf_error(filename, "Too many sections"); 893 error = ENOEXEC; 894 goto out; 895 } 896 /* 897 * XXX: We just trust they come in right order ?? 898 */ 899 segs[nsegs] = phdr; 900 ++nsegs; 901 break; 902 903 case PT_PHDR: 904 phphdr = phdr; 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_offset = trunc_page(segs[0]->p_offset); 935 base_vaddr = trunc_page(segs[0]->p_vaddr); 936 base_vlimit = round_page(segs[nsegs - 1]->p_vaddr + 937 segs[nsegs - 1]->p_memsz); 938 mapsize = base_vlimit - base_vaddr; 939 940 lf = linker_make_file(filename, &link_elf_class); 941 if (lf == NULL) { 942 error = ENOMEM; 943 goto out; 944 } 945 946 ef = (elf_file_t) lf; 947 #ifdef SPARSE_MAPPING 948 ef->object = vm_object_allocate(OBJT_DEFAULT, mapsize >> PAGE_SHIFT); 949 if (ef->object == NULL) { 950 error = ENOMEM; 951 goto out; 952 } 953 ef->address = (caddr_t) vm_map_min(kernel_map); 954 error = vm_map_find(kernel_map, ef->object, 0, 955 (vm_offset_t *) &ef->address, mapsize, 0, VMFS_OPTIMAL_SPACE, 956 VM_PROT_ALL, VM_PROT_ALL, 0); 957 if (error != 0) { 958 vm_object_deallocate(ef->object); 959 ef->object = 0; 960 goto out; 961 } 962 #else 963 ef->address = malloc(mapsize, M_LINKER, M_WAITOK); 964 #endif 965 mapbase = ef->address; 966 967 /* 968 * Read the text and data sections and zero the bss. 969 */ 970 for (i = 0; i < nsegs; i++) { 971 caddr_t segbase = mapbase + segs[i]->p_vaddr - base_vaddr; 972 error = vn_rdwr(UIO_READ, nd.ni_vp, 973 segbase, segs[i]->p_filesz, segs[i]->p_offset, 974 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 975 &resid, td); 976 if (error != 0) 977 goto out; 978 bzero(segbase + segs[i]->p_filesz, 979 segs[i]->p_memsz - segs[i]->p_filesz); 980 981 #ifdef SPARSE_MAPPING 982 /* 983 * Wire down the pages 984 */ 985 error = vm_map_wire(kernel_map, 986 (vm_offset_t) segbase, 987 (vm_offset_t) segbase + segs[i]->p_memsz, 988 VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES); 989 if (error != KERN_SUCCESS) { 990 error = ENOMEM; 991 goto out; 992 } 993 #endif 994 } 995 996 #ifdef GPROF 997 /* Update profiling information with the new text segment. */ 998 mtx_lock(&Giant); 999 kmupetext((uintfptr_t)(mapbase + segs[0]->p_vaddr - base_vaddr + 1000 segs[0]->p_memsz)); 1001 mtx_unlock(&Giant); 1002 #endif 1003 1004 ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr); 1005 1006 lf->address = ef->address; 1007 lf->size = mapsize; 1008 1009 error = parse_dynamic(ef); 1010 if (error != 0) 1011 goto out; 1012 error = parse_dpcpu(ef); 1013 if (error != 0) 1014 goto out; 1015 #ifdef VIMAGE 1016 error = parse_vnet(ef); 1017 if (error != 0) 1018 goto out; 1019 #endif 1020 link_elf_reloc_local(lf); 1021 1022 VOP_UNLOCK(nd.ni_vp, 0); 1023 error = linker_load_dependencies(lf); 1024 vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY); 1025 if (error != 0) 1026 goto out; 1027 error = relocate_file(ef); 1028 if (error != 0) 1029 goto out; 1030 1031 /* 1032 * Try and load the symbol table if it's present. (you can 1033 * strip it!) 1034 */ 1035 nbytes = hdr->e_shnum * hdr->e_shentsize; 1036 if (nbytes == 0 || hdr->e_shoff == 0) 1037 goto nosyms; 1038 shdr = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO); 1039 error = vn_rdwr(UIO_READ, nd.ni_vp, 1040 (caddr_t)shdr, nbytes, hdr->e_shoff, 1041 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1042 &resid, td); 1043 if (error != 0) 1044 goto out; 1045 1046 /* Read section string table */ 1047 shstrindex = hdr->e_shstrndx; 1048 if (shstrindex != 0 && shdr[shstrindex].sh_type == SHT_STRTAB && 1049 shdr[shstrindex].sh_size != 0) { 1050 nbytes = shdr[shstrindex].sh_size; 1051 shstrs = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO); 1052 error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)shstrs, nbytes, 1053 shdr[shstrindex].sh_offset, UIO_SYSSPACE, IO_NODELOCKED, 1054 td->td_ucred, NOCRED, &resid, td); 1055 if (error) 1056 goto out; 1057 } 1058 1059 symtabindex = -1; 1060 symstrindex = -1; 1061 for (i = 0; i < hdr->e_shnum; i++) { 1062 if (shdr[i].sh_type == SHT_SYMTAB) { 1063 symtabindex = i; 1064 symstrindex = shdr[i].sh_link; 1065 } else if (shstrs != NULL && shdr[i].sh_name != 0 && 1066 strcmp(shstrs + shdr[i].sh_name, ".ctors") == 0) { 1067 /* Record relocated address and size of .ctors. */ 1068 lf->ctors_addr = mapbase + shdr[i].sh_addr - base_vaddr; 1069 lf->ctors_size = shdr[i].sh_size; 1070 } 1071 } 1072 if (symtabindex < 0 || symstrindex < 0) 1073 goto nosyms; 1074 1075 symcnt = shdr[symtabindex].sh_size; 1076 ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK); 1077 strcnt = shdr[symstrindex].sh_size; 1078 ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK); 1079 1080 error = vn_rdwr(UIO_READ, nd.ni_vp, 1081 ef->symbase, symcnt, shdr[symtabindex].sh_offset, 1082 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1083 &resid, td); 1084 if (error != 0) 1085 goto out; 1086 error = vn_rdwr(UIO_READ, nd.ni_vp, 1087 ef->strbase, strcnt, shdr[symstrindex].sh_offset, 1088 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1089 &resid, td); 1090 if (error != 0) 1091 goto out; 1092 1093 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym); 1094 ef->ddbsymtab = (const Elf_Sym *)ef->symbase; 1095 ef->ddbstrcnt = strcnt; 1096 ef->ddbstrtab = ef->strbase; 1097 1098 nosyms: 1099 error = link_elf_link_common_finish(lf); 1100 if (error != 0) 1101 goto out; 1102 1103 *result = lf; 1104 1105 out: 1106 VOP_UNLOCK(nd.ni_vp, 0); 1107 vn_close(nd.ni_vp, FREAD, td->td_ucred, td); 1108 if (error != 0 && lf != NULL) 1109 linker_file_unload(lf, LINKER_UNLOAD_FORCE); 1110 free(shdr, M_LINKER); 1111 free(firstpage, M_LINKER); 1112 free(shstrs, M_LINKER); 1113 1114 return (error); 1115 } 1116 1117 Elf_Addr 1118 elf_relocaddr(linker_file_t lf, Elf_Addr x) 1119 { 1120 elf_file_t ef; 1121 1122 ef = (elf_file_t)lf; 1123 if (x >= ef->pcpu_start && x < ef->pcpu_stop) 1124 return ((x - ef->pcpu_start) + ef->pcpu_base); 1125 #ifdef VIMAGE 1126 if (x >= ef->vnet_start && x < ef->vnet_stop) 1127 return ((x - ef->vnet_start) + ef->vnet_base); 1128 #endif 1129 return (x); 1130 } 1131 1132 1133 static void 1134 link_elf_unload_file(linker_file_t file) 1135 { 1136 elf_file_t ef = (elf_file_t) file; 1137 1138 if (ef->pcpu_base != 0) { 1139 dpcpu_free((void *)ef->pcpu_base, 1140 ef->pcpu_stop - ef->pcpu_start); 1141 elf_set_delete(&set_pcpu_list, ef->pcpu_start); 1142 } 1143 #ifdef VIMAGE 1144 if (ef->vnet_base != 0) { 1145 vnet_data_free((void *)ef->vnet_base, 1146 ef->vnet_stop - ef->vnet_start); 1147 elf_set_delete(&set_vnet_list, ef->vnet_start); 1148 } 1149 #endif 1150 #ifdef GDB 1151 if (ef->gdb.l_ld != NULL) { 1152 GDB_STATE(RT_DELETE); 1153 free((void *)(uintptr_t)ef->gdb.l_name, M_LINKER); 1154 link_elf_delete_gdb(&ef->gdb); 1155 GDB_STATE(RT_CONSISTENT); 1156 } 1157 #endif 1158 1159 /* Notify MD code that a module is being unloaded. */ 1160 elf_cpu_unload_file(file); 1161 1162 if (ef->preloaded) { 1163 link_elf_unload_preload(file); 1164 return; 1165 } 1166 1167 #ifdef SPARSE_MAPPING 1168 if (ef->object != NULL) { 1169 vm_map_remove(kernel_map, (vm_offset_t) ef->address, 1170 (vm_offset_t) ef->address 1171 + (ef->object->size << PAGE_SHIFT)); 1172 } 1173 #else 1174 free(ef->address, M_LINKER); 1175 #endif 1176 free(ef->symbase, M_LINKER); 1177 free(ef->strbase, M_LINKER); 1178 free(ef->ctftab, M_LINKER); 1179 free(ef->ctfoff, M_LINKER); 1180 free(ef->typoff, M_LINKER); 1181 } 1182 1183 static void 1184 link_elf_unload_preload(linker_file_t file) 1185 { 1186 if (file->pathname != NULL) 1187 preload_delete_name(file->pathname); 1188 } 1189 1190 static const char * 1191 symbol_name(elf_file_t ef, Elf_Size r_info) 1192 { 1193 const Elf_Sym *ref; 1194 1195 if (ELF_R_SYM(r_info)) { 1196 ref = ef->symtab + ELF_R_SYM(r_info); 1197 return (ef->strtab + ref->st_name); 1198 } 1199 return (NULL); 1200 } 1201 1202 static int 1203 symbol_type(elf_file_t ef, Elf_Size r_info) 1204 { 1205 const Elf_Sym *ref; 1206 1207 if (ELF_R_SYM(r_info)) { 1208 ref = ef->symtab + ELF_R_SYM(r_info); 1209 return (ELF_ST_TYPE(ref->st_info)); 1210 } 1211 return (STT_NOTYPE); 1212 } 1213 1214 static int 1215 relocate_file1(elf_file_t ef, elf_lookup_fn lookup, elf_reloc_fn reloc, 1216 bool ifuncs) 1217 { 1218 const Elf_Rel *rel; 1219 const Elf_Rela *rela; 1220 const char *symname; 1221 1222 #define APPLY_RELOCS(iter, tbl, tblsize, type) do { \ 1223 for ((iter) = (tbl); (iter) != NULL && \ 1224 (iter) < (tbl) + (tblsize) / sizeof(*(iter)); (iter)++) { \ 1225 if ((symbol_type(ef, (iter)->r_info) == \ 1226 STT_GNU_IFUNC || \ 1227 elf_is_ifunc_reloc((iter)->r_info)) != ifuncs) \ 1228 continue; \ 1229 if (reloc(&ef->lf, (Elf_Addr)ef->address, \ 1230 (iter), (type), lookup)) { \ 1231 symname = symbol_name(ef, (iter)->r_info); \ 1232 printf("link_elf: symbol %s undefined\n", \ 1233 symname); \ 1234 return (ENOENT); \ 1235 } \ 1236 } \ 1237 } while (0) 1238 1239 APPLY_RELOCS(rel, ef->rel, ef->relsize, ELF_RELOC_REL); 1240 APPLY_RELOCS(rela, ef->rela, ef->relasize, ELF_RELOC_RELA); 1241 APPLY_RELOCS(rel, ef->pltrel, ef->pltrelsize, ELF_RELOC_REL); 1242 APPLY_RELOCS(rela, ef->pltrela, ef->pltrelasize, ELF_RELOC_RELA); 1243 1244 #undef APPLY_RELOCS 1245 1246 return (0); 1247 } 1248 1249 static int 1250 relocate_file(elf_file_t ef) 1251 { 1252 int error; 1253 1254 error = relocate_file1(ef, elf_lookup, elf_reloc, false); 1255 if (error == 0) 1256 error = relocate_file1(ef, elf_lookup, elf_reloc, true); 1257 return (error); 1258 } 1259 1260 /* 1261 * Hash function for symbol table lookup. Don't even think about changing 1262 * this. It is specified by the System V ABI. 1263 */ 1264 static unsigned long 1265 elf_hash(const char *name) 1266 { 1267 const unsigned char *p = (const unsigned char *) name; 1268 unsigned long h = 0; 1269 unsigned long g; 1270 1271 while (*p != '\0') { 1272 h = (h << 4) + *p++; 1273 if ((g = h & 0xf0000000) != 0) 1274 h ^= g >> 24; 1275 h &= ~g; 1276 } 1277 return (h); 1278 } 1279 1280 static int 1281 link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym) 1282 { 1283 elf_file_t ef = (elf_file_t) lf; 1284 unsigned long symnum; 1285 const Elf_Sym* symp; 1286 const char *strp; 1287 unsigned long hash; 1288 int i; 1289 1290 /* If we don't have a hash, bail. */ 1291 if (ef->buckets == NULL || ef->nbuckets == 0) { 1292 printf("link_elf_lookup_symbol: missing symbol hash table\n"); 1293 return (ENOENT); 1294 } 1295 1296 /* First, search hashed global symbols */ 1297 hash = elf_hash(name); 1298 symnum = ef->buckets[hash % ef->nbuckets]; 1299 1300 while (symnum != STN_UNDEF) { 1301 if (symnum >= ef->nchains) { 1302 printf("%s: corrupt symbol table\n", __func__); 1303 return (ENOENT); 1304 } 1305 1306 symp = ef->symtab + symnum; 1307 if (symp->st_name == 0) { 1308 printf("%s: corrupt symbol table\n", __func__); 1309 return (ENOENT); 1310 } 1311 1312 strp = ef->strtab + symp->st_name; 1313 1314 if (strcmp(name, strp) == 0) { 1315 if (symp->st_shndx != SHN_UNDEF || 1316 (symp->st_value != 0 && 1317 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1318 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC))) { 1319 *sym = (c_linker_sym_t) symp; 1320 return (0); 1321 } 1322 return (ENOENT); 1323 } 1324 1325 symnum = ef->chains[symnum]; 1326 } 1327 1328 /* If we have not found it, look at the full table (if loaded) */ 1329 if (ef->symtab == ef->ddbsymtab) 1330 return (ENOENT); 1331 1332 /* Exhaustive search */ 1333 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1334 strp = ef->ddbstrtab + symp->st_name; 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 1347 return (ENOENT); 1348 } 1349 1350 static int 1351 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, 1352 linker_symval_t *symval) 1353 { 1354 elf_file_t ef; 1355 const Elf_Sym *es; 1356 caddr_t val; 1357 1358 ef = (elf_file_t)lf; 1359 es = (const Elf_Sym *)sym; 1360 if (es >= ef->symtab && es < (ef->symtab + ef->nchains)) { 1361 symval->name = ef->strtab + es->st_name; 1362 val = (caddr_t)ef->address + es->st_value; 1363 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC) 1364 val = ((caddr_t (*)(void))val)(); 1365 symval->value = val; 1366 symval->size = es->st_size; 1367 return (0); 1368 } 1369 if (ef->symtab == ef->ddbsymtab) 1370 return (ENOENT); 1371 if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) { 1372 symval->name = ef->ddbstrtab + es->st_name; 1373 val = (caddr_t)ef->address + es->st_value; 1374 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC) 1375 val = ((caddr_t (*)(void))val)(); 1376 symval->value = val; 1377 symval->size = es->st_size; 1378 return (0); 1379 } 1380 return (ENOENT); 1381 } 1382 1383 static int 1384 link_elf_search_symbol(linker_file_t lf, caddr_t value, 1385 c_linker_sym_t *sym, long *diffp) 1386 { 1387 elf_file_t ef = (elf_file_t) lf; 1388 u_long off = (uintptr_t) (void *) value; 1389 u_long diff = off; 1390 u_long st_value; 1391 const Elf_Sym* es; 1392 const Elf_Sym* best = NULL; 1393 int i; 1394 1395 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) { 1396 if (es->st_name == 0) 1397 continue; 1398 st_value = es->st_value + (uintptr_t) (void *) ef->address; 1399 if (off >= st_value) { 1400 if (off - st_value < diff) { 1401 diff = off - st_value; 1402 best = es; 1403 if (diff == 0) 1404 break; 1405 } else if (off - st_value == diff) { 1406 best = es; 1407 } 1408 } 1409 } 1410 if (best == NULL) 1411 *diffp = off; 1412 else 1413 *diffp = diff; 1414 *sym = (c_linker_sym_t) best; 1415 1416 return (0); 1417 } 1418 1419 /* 1420 * Look up a linker set on an ELF system. 1421 */ 1422 static int 1423 link_elf_lookup_set(linker_file_t lf, const char *name, 1424 void ***startp, void ***stopp, int *countp) 1425 { 1426 c_linker_sym_t sym; 1427 linker_symval_t symval; 1428 char *setsym; 1429 void **start, **stop; 1430 int len, error = 0, count; 1431 1432 len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */ 1433 setsym = malloc(len, M_LINKER, M_WAITOK); 1434 1435 /* get address of first entry */ 1436 snprintf(setsym, len, "%s%s", "__start_set_", name); 1437 error = link_elf_lookup_symbol(lf, setsym, &sym); 1438 if (error != 0) 1439 goto out; 1440 link_elf_symbol_values(lf, sym, &symval); 1441 if (symval.value == 0) { 1442 error = ESRCH; 1443 goto out; 1444 } 1445 start = (void **)symval.value; 1446 1447 /* get address of last entry */ 1448 snprintf(setsym, len, "%s%s", "__stop_set_", name); 1449 error = link_elf_lookup_symbol(lf, setsym, &sym); 1450 if (error != 0) 1451 goto out; 1452 link_elf_symbol_values(lf, sym, &symval); 1453 if (symval.value == 0) { 1454 error = ESRCH; 1455 goto out; 1456 } 1457 stop = (void **)symval.value; 1458 1459 /* and the number of entries */ 1460 count = stop - start; 1461 1462 /* and copy out */ 1463 if (startp != NULL) 1464 *startp = start; 1465 if (stopp != NULL) 1466 *stopp = stop; 1467 if (countp != NULL) 1468 *countp = count; 1469 1470 out: 1471 free(setsym, M_LINKER); 1472 return (error); 1473 } 1474 1475 static int 1476 link_elf_each_function_name(linker_file_t file, 1477 int (*callback)(const char *, void *), void *opaque) 1478 { 1479 elf_file_t ef = (elf_file_t)file; 1480 const Elf_Sym *symp; 1481 int i, error; 1482 1483 /* Exhaustive search */ 1484 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1485 if (symp->st_value != 0 && 1486 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1487 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) { 1488 error = callback(ef->ddbstrtab + symp->st_name, opaque); 1489 if (error != 0) 1490 return (error); 1491 } 1492 } 1493 return (0); 1494 } 1495 1496 static int 1497 link_elf_each_function_nameval(linker_file_t file, 1498 linker_function_nameval_callback_t callback, void *opaque) 1499 { 1500 linker_symval_t symval; 1501 elf_file_t ef = (elf_file_t)file; 1502 const Elf_Sym* symp; 1503 int i, error; 1504 1505 /* Exhaustive search */ 1506 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1507 if (symp->st_value != 0 && 1508 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1509 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) { 1510 error = link_elf_symbol_values(file, 1511 (c_linker_sym_t) symp, &symval); 1512 if (error != 0) 1513 return (error); 1514 error = callback(file, i, &symval, opaque); 1515 if (error != 0) 1516 return (error); 1517 } 1518 } 1519 return (0); 1520 } 1521 1522 const Elf_Sym * 1523 elf_get_sym(linker_file_t lf, Elf_Size symidx) 1524 { 1525 elf_file_t ef = (elf_file_t)lf; 1526 1527 if (symidx >= ef->nchains) 1528 return (NULL); 1529 return (ef->symtab + symidx); 1530 } 1531 1532 const char * 1533 elf_get_symname(linker_file_t lf, Elf_Size symidx) 1534 { 1535 elf_file_t ef = (elf_file_t)lf; 1536 const Elf_Sym *sym; 1537 1538 if (symidx >= ef->nchains) 1539 return (NULL); 1540 sym = ef->symtab + symidx; 1541 return (ef->strtab + sym->st_name); 1542 } 1543 1544 /* 1545 * Symbol lookup function that can be used when the symbol index is known (ie 1546 * in relocations). It uses the symbol index instead of doing a fully fledged 1547 * hash table based lookup when such is valid. For example for local symbols. 1548 * This is not only more efficient, it's also more correct. It's not always 1549 * the case that the symbol can be found through the hash table. 1550 */ 1551 static int 1552 elf_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res) 1553 { 1554 elf_file_t ef = (elf_file_t)lf; 1555 const Elf_Sym *sym; 1556 const char *symbol; 1557 Elf_Addr addr, start, base; 1558 1559 /* Don't even try to lookup the symbol if the index is bogus. */ 1560 if (symidx >= ef->nchains) { 1561 *res = 0; 1562 return (EINVAL); 1563 } 1564 1565 sym = ef->symtab + symidx; 1566 1567 /* 1568 * Don't do a full lookup when the symbol is local. It may even 1569 * fail because it may not be found through the hash table. 1570 */ 1571 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) { 1572 /* Force lookup failure when we have an insanity. */ 1573 if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0) { 1574 *res = 0; 1575 return (EINVAL); 1576 } 1577 *res = ((Elf_Addr)ef->address + sym->st_value); 1578 return (0); 1579 } 1580 1581 /* 1582 * XXX we can avoid doing a hash table based lookup for global 1583 * symbols as well. This however is not always valid, so we'll 1584 * just do it the hard way for now. Performance tweaks can 1585 * always be added. 1586 */ 1587 1588 symbol = ef->strtab + sym->st_name; 1589 1590 /* Force a lookup failure if the symbol name is bogus. */ 1591 if (*symbol == 0) { 1592 *res = 0; 1593 return (EINVAL); 1594 } 1595 1596 addr = ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps)); 1597 if (addr == 0 && ELF_ST_BIND(sym->st_info) != STB_WEAK) { 1598 *res = 0; 1599 return (EINVAL); 1600 } 1601 1602 if (elf_set_find(&set_pcpu_list, addr, &start, &base)) 1603 addr = addr - start + base; 1604 #ifdef VIMAGE 1605 else if (elf_set_find(&set_vnet_list, addr, &start, &base)) 1606 addr = addr - start + base; 1607 #endif 1608 *res = addr; 1609 return (0); 1610 } 1611 1612 static void 1613 link_elf_reloc_local(linker_file_t lf) 1614 { 1615 const Elf_Rel *rellim; 1616 const Elf_Rel *rel; 1617 const Elf_Rela *relalim; 1618 const Elf_Rela *rela; 1619 elf_file_t ef = (elf_file_t)lf; 1620 1621 /* Perform relocations without addend if there are any: */ 1622 if ((rel = ef->rel) != NULL) { 1623 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize); 1624 while (rel < rellim) { 1625 elf_reloc_local(lf, (Elf_Addr)ef->address, rel, 1626 ELF_RELOC_REL, elf_lookup); 1627 rel++; 1628 } 1629 } 1630 1631 /* Perform relocations with addend if there are any: */ 1632 if ((rela = ef->rela) != NULL) { 1633 relalim = (const Elf_Rela *) 1634 ((const char *)ef->rela + ef->relasize); 1635 while (rela < relalim) { 1636 elf_reloc_local(lf, (Elf_Addr)ef->address, rela, 1637 ELF_RELOC_RELA, elf_lookup); 1638 rela++; 1639 } 1640 } 1641 } 1642 1643 static long 1644 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab) 1645 { 1646 elf_file_t ef = (elf_file_t)lf; 1647 1648 *symtab = ef->ddbsymtab; 1649 1650 if (*symtab == NULL) 1651 return (0); 1652 1653 return (ef->ddbsymcnt); 1654 } 1655 1656 static long 1657 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab) 1658 { 1659 elf_file_t ef = (elf_file_t)lf; 1660 1661 *strtab = ef->ddbstrtab; 1662 1663 if (*strtab == NULL) 1664 return (0); 1665 1666 return (ef->ddbstrcnt); 1667 } 1668 1669 #if defined(__i386__) || defined(__amd64__) 1670 /* 1671 * Use this lookup routine when performing relocations early during boot. 1672 * The generic lookup routine depends on kobj, which is not initialized 1673 * at that point. 1674 */ 1675 static int 1676 elf_lookup_ifunc(linker_file_t lf, Elf_Size symidx, int deps __unused, 1677 Elf_Addr *res) 1678 { 1679 elf_file_t ef; 1680 const Elf_Sym *symp; 1681 caddr_t val; 1682 1683 ef = (elf_file_t)lf; 1684 symp = ef->symtab + symidx; 1685 if (ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC) { 1686 val = (caddr_t)ef->address + symp->st_value; 1687 *res = ((Elf_Addr (*)(void))val)(); 1688 return (0); 1689 } 1690 return (ENOENT); 1691 } 1692 1693 void 1694 link_elf_ireloc(caddr_t kmdp) 1695 { 1696 struct elf_file eff; 1697 elf_file_t ef; 1698 volatile char *c; 1699 size_t i; 1700 1701 ef = &eff; 1702 1703 /* Do not use bzero/memset before ireloc is done. */ 1704 for (c = (char *)ef, i = 0; i < sizeof(*ef); i++) 1705 c[i] = 0; 1706 1707 ef->modptr = kmdp; 1708 ef->dynamic = (Elf_Dyn *)&_DYNAMIC; 1709 parse_dynamic(ef); 1710 ef->address = 0; 1711 link_elf_preload_parse_symbols(ef); 1712 relocate_file1(ef, elf_lookup_ifunc, elf_reloc, true); 1713 } 1714 #endif
Cache object: d55621bdf25612f54f9b5715849bf5fb
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