Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/kern/link_elf.c
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1 /*- 2 * Copyright (c) 1998-2000 Doug Rabson 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 */ 26 27 #include <sys/cdefs.h> 28 __FBSDID("$FreeBSD: releng/9.1/sys/kern/link_elf.c 233353 2012-03-23 11:26:54Z kib $"); 29 30 #include "opt_ddb.h" 31 #include "opt_gdb.h" 32 33 #include <sys/param.h> 34 #include <sys/systm.h> 35 #ifdef GPROF 36 #include <sys/gmon.h> 37 #endif 38 #include <sys/kernel.h> 39 #include <sys/lock.h> 40 #include <sys/malloc.h> 41 #include <sys/mutex.h> 42 #include <sys/mount.h> 43 #include <sys/pcpu.h> 44 #include <sys/proc.h> 45 #include <sys/namei.h> 46 #include <sys/fcntl.h> 47 #include <sys/vnode.h> 48 #include <sys/linker.h> 49 50 #include <machine/elf.h> 51 52 #include <net/vnet.h> 53 54 #include <security/mac/mac_framework.h> 55 56 #include <vm/vm.h> 57 #include <vm/vm_param.h> 58 #ifdef SPARSE_MAPPING 59 #include <vm/vm_object.h> 60 #include <vm/vm_kern.h> 61 #include <vm/vm_extern.h> 62 #endif 63 #include <vm/pmap.h> 64 #include <vm/vm_map.h> 65 66 #include <sys/link_elf.h> 67 68 #ifdef DDB_CTF 69 #include <net/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 #include <kern/kern_ctf.c> 127 128 static int link_elf_link_common_finish(linker_file_t); 129 static int link_elf_link_preload(linker_class_t cls, 130 const char *, linker_file_t *); 131 static int link_elf_link_preload_finish(linker_file_t); 132 static int link_elf_load_file(linker_class_t, const char *, 133 linker_file_t *); 134 static int link_elf_lookup_symbol(linker_file_t, const char *, 135 c_linker_sym_t *); 136 static int link_elf_symbol_values(linker_file_t, c_linker_sym_t, 137 linker_symval_t *); 138 static int link_elf_search_symbol(linker_file_t, caddr_t, 139 c_linker_sym_t *, long *); 140 141 static void link_elf_unload_file(linker_file_t); 142 static void link_elf_unload_preload(linker_file_t); 143 static int link_elf_lookup_set(linker_file_t, const char *, 144 void ***, void ***, int *); 145 static int link_elf_each_function_name(linker_file_t, 146 int (*)(const char *, void *), void *); 147 static int link_elf_each_function_nameval(linker_file_t, 148 linker_function_nameval_callback_t, void *); 149 static void link_elf_reloc_local(linker_file_t); 150 static long link_elf_symtab_get(linker_file_t, const Elf_Sym **); 151 static long link_elf_strtab_get(linker_file_t, caddr_t *); 152 static Elf_Addr elf_lookup(linker_file_t, Elf_Size, int); 153 154 static kobj_method_t link_elf_methods[] = { 155 KOBJMETHOD(linker_lookup_symbol, link_elf_lookup_symbol), 156 KOBJMETHOD(linker_symbol_values, link_elf_symbol_values), 157 KOBJMETHOD(linker_search_symbol, link_elf_search_symbol), 158 KOBJMETHOD(linker_unload, link_elf_unload_file), 159 KOBJMETHOD(linker_load_file, link_elf_load_file), 160 KOBJMETHOD(linker_link_preload, link_elf_link_preload), 161 KOBJMETHOD(linker_link_preload_finish, link_elf_link_preload_finish), 162 KOBJMETHOD(linker_lookup_set, link_elf_lookup_set), 163 KOBJMETHOD(linker_each_function_name, link_elf_each_function_name), 164 KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval), 165 KOBJMETHOD(linker_ctf_get, link_elf_ctf_get), 166 KOBJMETHOD(linker_symtab_get, link_elf_symtab_get), 167 KOBJMETHOD(linker_strtab_get, link_elf_strtab_get), 168 { 0, 0 } 169 }; 170 171 static struct linker_class link_elf_class = { 172 #if ELF_TARG_CLASS == ELFCLASS32 173 "elf32", 174 #else 175 "elf64", 176 #endif 177 link_elf_methods, sizeof(struct elf_file) 178 }; 179 180 static int parse_dynamic(elf_file_t); 181 static int relocate_file(elf_file_t); 182 static int link_elf_preload_parse_symbols(elf_file_t); 183 184 #ifdef GDB 185 static void r_debug_state(struct r_debug *, struct link_map *); 186 187 /* 188 * A list of loaded modules for GDB to use for loading symbols. 189 */ 190 struct r_debug r_debug; 191 192 #define GDB_STATE(s) do { \ 193 r_debug.r_state = s; r_debug_state(NULL, NULL); \ 194 } while (0) 195 196 /* 197 * Function for the debugger to set a breakpoint on to gain control. 198 */ 199 static void 200 r_debug_state(struct r_debug *dummy_one __unused, 201 struct link_map *dummy_two __unused) 202 { 203 } 204 205 static void 206 link_elf_add_gdb(struct link_map *l) 207 { 208 struct link_map *prev; 209 210 l->l_next = NULL; 211 212 if (r_debug.r_map == NULL) { 213 /* Add first. */ 214 l->l_prev = NULL; 215 r_debug.r_map = l; 216 } else { 217 /* Append to list. */ 218 for (prev = r_debug.r_map; 219 prev->l_next != NULL; 220 prev = prev->l_next) 221 ; 222 l->l_prev = prev; 223 prev->l_next = l; 224 } 225 } 226 227 static void 228 link_elf_delete_gdb(struct link_map *l) 229 { 230 if (l->l_prev == NULL) { 231 /* Remove first. */ 232 if ((r_debug.r_map = l->l_next) != NULL) 233 l->l_next->l_prev = NULL; 234 } else { 235 /* Remove any but first. */ 236 if ((l->l_prev->l_next = l->l_next) != NULL) 237 l->l_next->l_prev = l->l_prev; 238 } 239 } 240 #endif /* GDB */ 241 242 #ifdef __ia64__ 243 Elf_Addr link_elf_get_gp(linker_file_t); 244 #endif 245 246 /* 247 * The kernel symbol table starts here. 248 */ 249 extern struct _dynamic _DYNAMIC; 250 251 static void 252 link_elf_error(const char *filename, const char *s) 253 { 254 if (filename == NULL) 255 printf("kldload: %s\n", s); 256 else 257 printf("kldload: %s: %s\n", filename, s); 258 } 259 260 /* 261 * Actions performed after linking/loading both the preloaded kernel and any 262 * modules; whether preloaded or dynamicly loaded. 263 */ 264 static int 265 link_elf_link_common_finish(linker_file_t lf) 266 { 267 #ifdef GDB 268 elf_file_t ef = (elf_file_t)lf; 269 char *newfilename; 270 #endif 271 int error; 272 273 /* Notify MD code that a module is being loaded. */ 274 error = elf_cpu_load_file(lf); 275 if (error != 0) 276 return (error); 277 278 #ifdef GDB 279 GDB_STATE(RT_ADD); 280 ef->gdb.l_addr = lf->address; 281 newfilename = malloc(strlen(lf->filename) + 1, M_LINKER, M_WAITOK); 282 strcpy(newfilename, lf->filename); 283 ef->gdb.l_name = newfilename; 284 ef->gdb.l_ld = ef->dynamic; 285 link_elf_add_gdb(&ef->gdb); 286 GDB_STATE(RT_CONSISTENT); 287 #endif 288 289 return (0); 290 } 291 292 static void 293 link_elf_init(void* arg) 294 { 295 Elf_Dyn *dp; 296 caddr_t modptr, baseptr, sizeptr; 297 elf_file_t ef; 298 char *modname; 299 300 linker_add_class(&link_elf_class); 301 302 dp = (Elf_Dyn *)&_DYNAMIC; 303 modname = NULL; 304 modptr = preload_search_by_type("elf" __XSTRING(__ELF_WORD_SIZE) " kernel"); 305 if (modptr == NULL) 306 modptr = preload_search_by_type("elf kernel"); 307 if (modptr != NULL) 308 modname = (char *)preload_search_info(modptr, MODINFO_NAME); 309 if (modname == NULL) 310 modname = "kernel"; 311 linker_kernel_file = linker_make_file(modname, &link_elf_class); 312 if (linker_kernel_file == NULL) 313 panic("%s: Can't create linker structures for kernel", 314 __func__); 315 316 ef = (elf_file_t) linker_kernel_file; 317 ef->preloaded = 1; 318 ef->address = 0; 319 #ifdef SPARSE_MAPPING 320 ef->object = 0; 321 #endif 322 ef->dynamic = dp; 323 324 if (dp != NULL) 325 parse_dynamic(ef); 326 linker_kernel_file->address = (caddr_t) KERNBASE; 327 linker_kernel_file->size = -(intptr_t)linker_kernel_file->address; 328 329 if (modptr != NULL) { 330 ef->modptr = modptr; 331 baseptr = preload_search_info(modptr, MODINFO_ADDR); 332 if (baseptr != NULL) 333 linker_kernel_file->address = *(caddr_t *)baseptr; 334 sizeptr = preload_search_info(modptr, MODINFO_SIZE); 335 if (sizeptr != NULL) 336 linker_kernel_file->size = *(size_t *)sizeptr; 337 } 338 (void)link_elf_preload_parse_symbols(ef); 339 340 #ifdef GDB 341 r_debug.r_map = NULL; 342 r_debug.r_brk = r_debug_state; 343 r_debug.r_state = RT_CONSISTENT; 344 #endif 345 346 (void)link_elf_link_common_finish(linker_kernel_file); 347 linker_kernel_file->flags |= LINKER_FILE_LINKED; 348 } 349 350 SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_THIRD, link_elf_init, 0); 351 352 static int 353 link_elf_preload_parse_symbols(elf_file_t ef) 354 { 355 caddr_t pointer; 356 caddr_t ssym, esym, base; 357 caddr_t strtab; 358 int strcnt; 359 Elf_Sym *symtab; 360 int symcnt; 361 362 if (ef->modptr == NULL) 363 return (0); 364 pointer = preload_search_info(ef->modptr, 365 MODINFO_METADATA | MODINFOMD_SSYM); 366 if (pointer == NULL) 367 return (0); 368 ssym = *(caddr_t *)pointer; 369 pointer = preload_search_info(ef->modptr, 370 MODINFO_METADATA | MODINFOMD_ESYM); 371 if (pointer == NULL) 372 return (0); 373 esym = *(caddr_t *)pointer; 374 375 base = ssym; 376 377 symcnt = *(long *)base; 378 base += sizeof(long); 379 symtab = (Elf_Sym *)base; 380 base += roundup(symcnt, sizeof(long)); 381 382 if (base > esym || base < ssym) { 383 printf("Symbols are corrupt!\n"); 384 return (EINVAL); 385 } 386 387 strcnt = *(long *)base; 388 base += sizeof(long); 389 strtab = base; 390 base += roundup(strcnt, sizeof(long)); 391 392 if (base > esym || base < ssym) { 393 printf("Symbols are corrupt!\n"); 394 return (EINVAL); 395 } 396 397 ef->ddbsymtab = symtab; 398 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym); 399 ef->ddbstrtab = strtab; 400 ef->ddbstrcnt = strcnt; 401 402 return (0); 403 } 404 405 static int 406 parse_dynamic(elf_file_t ef) 407 { 408 Elf_Dyn *dp; 409 int plttype = DT_REL; 410 411 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) { 412 switch (dp->d_tag) { 413 case DT_HASH: 414 { 415 /* From src/libexec/rtld-elf/rtld.c */ 416 const Elf_Hashelt *hashtab = (const Elf_Hashelt *) 417 (ef->address + dp->d_un.d_ptr); 418 ef->nbuckets = hashtab[0]; 419 ef->nchains = hashtab[1]; 420 ef->buckets = hashtab + 2; 421 ef->chains = ef->buckets + ef->nbuckets; 422 break; 423 } 424 case DT_STRTAB: 425 ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr); 426 break; 427 case DT_STRSZ: 428 ef->strsz = dp->d_un.d_val; 429 break; 430 case DT_SYMTAB: 431 ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr); 432 break; 433 case DT_SYMENT: 434 if (dp->d_un.d_val != sizeof(Elf_Sym)) 435 return (ENOEXEC); 436 break; 437 case DT_PLTGOT: 438 ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr); 439 break; 440 case DT_REL: 441 ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr); 442 break; 443 case DT_RELSZ: 444 ef->relsize = dp->d_un.d_val; 445 break; 446 case DT_RELENT: 447 if (dp->d_un.d_val != sizeof(Elf_Rel)) 448 return (ENOEXEC); 449 break; 450 case DT_JMPREL: 451 ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr); 452 break; 453 case DT_PLTRELSZ: 454 ef->pltrelsize = dp->d_un.d_val; 455 break; 456 case DT_RELA: 457 ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr); 458 break; 459 case DT_RELASZ: 460 ef->relasize = dp->d_un.d_val; 461 break; 462 case DT_RELAENT: 463 if (dp->d_un.d_val != sizeof(Elf_Rela)) 464 return (ENOEXEC); 465 break; 466 case DT_PLTREL: 467 plttype = dp->d_un.d_val; 468 if (plttype != DT_REL && plttype != DT_RELA) 469 return (ENOEXEC); 470 break; 471 #ifdef GDB 472 case DT_DEBUG: 473 dp->d_un.d_ptr = (Elf_Addr)&r_debug; 474 break; 475 #endif 476 } 477 } 478 479 if (plttype == DT_RELA) { 480 ef->pltrela = (const Elf_Rela *)ef->pltrel; 481 ef->pltrel = NULL; 482 ef->pltrelasize = ef->pltrelsize; 483 ef->pltrelsize = 0; 484 } 485 486 ef->ddbsymtab = ef->symtab; 487 ef->ddbsymcnt = ef->nchains; 488 ef->ddbstrtab = ef->strtab; 489 ef->ddbstrcnt = ef->strsz; 490 491 return (0); 492 } 493 494 static int 495 parse_dpcpu(elf_file_t ef) 496 { 497 int count; 498 int error; 499 500 ef->pcpu_start = 0; 501 ef->pcpu_stop = 0; 502 error = link_elf_lookup_set(&ef->lf, "pcpu", (void ***)&ef->pcpu_start, 503 (void ***)&ef->pcpu_stop, &count); 504 /* Error just means there is no pcpu set to relocate. */ 505 if (error != 0) 506 return (0); 507 count *= sizeof(void *); 508 /* 509 * Allocate space in the primary pcpu area. Copy in our 510 * initialization from the data section and then initialize 511 * all per-cpu storage from that. 512 */ 513 ef->pcpu_base = (Elf_Addr)(uintptr_t)dpcpu_alloc(count); 514 if (ef->pcpu_base == 0) 515 return (ENOSPC); 516 memcpy((void *)ef->pcpu_base, (void *)ef->pcpu_start, count); 517 dpcpu_copy((void *)ef->pcpu_base, count); 518 519 return (0); 520 } 521 522 #ifdef VIMAGE 523 static int 524 parse_vnet(elf_file_t ef) 525 { 526 int count; 527 int error; 528 529 ef->vnet_start = 0; 530 ef->vnet_stop = 0; 531 error = link_elf_lookup_set(&ef->lf, "vnet", (void ***)&ef->vnet_start, 532 (void ***)&ef->vnet_stop, &count); 533 /* Error just means there is no vnet data set to relocate. */ 534 if (error != 0) 535 return (0); 536 count *= sizeof(void *); 537 /* 538 * Allocate space in the primary vnet area. Copy in our 539 * initialization from the data section and then initialize 540 * all per-vnet storage from that. 541 */ 542 ef->vnet_base = (Elf_Addr)(uintptr_t)vnet_data_alloc(count); 543 if (ef->vnet_base == 0) 544 return (ENOSPC); 545 memcpy((void *)ef->vnet_base, (void *)ef->vnet_start, count); 546 vnet_data_copy((void *)ef->vnet_base, count); 547 548 return (0); 549 } 550 #endif 551 552 static int 553 link_elf_link_preload(linker_class_t cls, 554 const char* filename, linker_file_t *result) 555 { 556 caddr_t modptr, baseptr, sizeptr, dynptr; 557 char *type; 558 elf_file_t ef; 559 linker_file_t lf; 560 int error; 561 vm_offset_t dp; 562 563 /* Look to see if we have the file preloaded */ 564 modptr = preload_search_by_name(filename); 565 if (modptr == NULL) 566 return (ENOENT); 567 568 type = (char *)preload_search_info(modptr, MODINFO_TYPE); 569 baseptr = preload_search_info(modptr, MODINFO_ADDR); 570 sizeptr = preload_search_info(modptr, MODINFO_SIZE); 571 dynptr = preload_search_info(modptr, 572 MODINFO_METADATA | MODINFOMD_DYNAMIC); 573 if (type == NULL || 574 (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) " module") != 0 && 575 strcmp(type, "elf module") != 0)) 576 return (EFTYPE); 577 if (baseptr == NULL || sizeptr == NULL || dynptr == NULL) 578 return (EINVAL); 579 580 lf = linker_make_file(filename, &link_elf_class); 581 if (lf == NULL) 582 return (ENOMEM); 583 584 ef = (elf_file_t) lf; 585 ef->preloaded = 1; 586 ef->modptr = modptr; 587 ef->address = *(caddr_t *)baseptr; 588 #ifdef SPARSE_MAPPING 589 ef->object = 0; 590 #endif 591 dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr; 592 ef->dynamic = (Elf_Dyn *)dp; 593 lf->address = ef->address; 594 lf->size = *(size_t *)sizeptr; 595 596 error = parse_dynamic(ef); 597 if (error == 0) 598 error = parse_dpcpu(ef); 599 #ifdef VIMAGE 600 if (error == 0) 601 error = parse_vnet(ef); 602 #endif 603 if (error != 0) { 604 linker_file_unload(lf, LINKER_UNLOAD_FORCE); 605 return (error); 606 } 607 link_elf_reloc_local(lf); 608 *result = lf; 609 return (0); 610 } 611 612 static int 613 link_elf_link_preload_finish(linker_file_t lf) 614 { 615 elf_file_t ef; 616 int error; 617 618 ef = (elf_file_t) lf; 619 #if 0 /* this will be more trouble than it's worth for now */ 620 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) { 621 if (dp->d_tag != DT_NEEDED) 622 continue; 623 modname = ef->strtab + dp->d_un.d_val; 624 error = linker_load_module(modname, lf); 625 if (error != 0) 626 goto out; 627 } 628 #endif 629 error = relocate_file(ef); 630 if (error != 0) 631 return (error); 632 (void)link_elf_preload_parse_symbols(ef); 633 634 return (link_elf_link_common_finish(lf)); 635 } 636 637 static int 638 link_elf_load_file(linker_class_t cls, const char* filename, 639 linker_file_t* result) 640 { 641 struct nameidata nd; 642 struct thread* td = curthread; /* XXX */ 643 Elf_Ehdr *hdr; 644 caddr_t firstpage; 645 int nbytes, i; 646 Elf_Phdr *phdr; 647 Elf_Phdr *phlimit; 648 Elf_Phdr *segs[MAXSEGS]; 649 int nsegs; 650 Elf_Phdr *phdyn; 651 Elf_Phdr *phphdr; 652 caddr_t mapbase; 653 size_t mapsize; 654 Elf_Off base_offset; 655 Elf_Addr base_vaddr; 656 Elf_Addr base_vlimit; 657 int error = 0; 658 ssize_t resid; 659 int flags; 660 elf_file_t ef; 661 linker_file_t lf; 662 Elf_Shdr *shdr; 663 int symtabindex; 664 int symstrindex; 665 int symcnt; 666 int strcnt; 667 int vfslocked; 668 669 shdr = NULL; 670 lf = NULL; 671 672 NDINIT(&nd, LOOKUP, FOLLOW | MPSAFE, UIO_SYSSPACE, filename, td); 673 flags = FREAD; 674 error = vn_open(&nd, &flags, 0, NULL); 675 if (error != 0) 676 return (error); 677 vfslocked = NDHASGIANT(&nd); 678 NDFREE(&nd, NDF_ONLY_PNBUF); 679 if (nd.ni_vp->v_type != VREG) { 680 error = ENOEXEC; 681 firstpage = NULL; 682 goto out; 683 } 684 #ifdef MAC 685 error = mac_kld_check_load(curthread->td_ucred, nd.ni_vp); 686 if (error != 0) { 687 firstpage = NULL; 688 goto out; 689 } 690 #endif 691 692 /* 693 * Read the elf header from the file. 694 */ 695 firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK); 696 hdr = (Elf_Ehdr *)firstpage; 697 error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0, 698 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 699 &resid, td); 700 nbytes = PAGE_SIZE - resid; 701 if (error != 0) 702 goto out; 703 704 if (!IS_ELF(*hdr)) { 705 error = ENOEXEC; 706 goto out; 707 } 708 709 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS || 710 hdr->e_ident[EI_DATA] != ELF_TARG_DATA) { 711 link_elf_error(filename, "Unsupported file layout"); 712 error = ENOEXEC; 713 goto out; 714 } 715 if (hdr->e_ident[EI_VERSION] != EV_CURRENT || 716 hdr->e_version != EV_CURRENT) { 717 link_elf_error(filename, "Unsupported file version"); 718 error = ENOEXEC; 719 goto out; 720 } 721 if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) { 722 error = ENOSYS; 723 goto out; 724 } 725 if (hdr->e_machine != ELF_TARG_MACH) { 726 link_elf_error(filename, "Unsupported machine"); 727 error = ENOEXEC; 728 goto out; 729 } 730 731 /* 732 * We rely on the program header being in the first page. 733 * This is not strictly required by the ABI specification, but 734 * it seems to always true in practice. And, it simplifies 735 * things considerably. 736 */ 737 if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) && 738 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) && 739 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes))) 740 link_elf_error(filename, "Unreadable program headers"); 741 742 /* 743 * Scan the program header entries, and save key information. 744 * 745 * We rely on there being exactly two load segments, text and data, 746 * in that order. 747 */ 748 phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff); 749 phlimit = phdr + hdr->e_phnum; 750 nsegs = 0; 751 phdyn = NULL; 752 phphdr = NULL; 753 while (phdr < phlimit) { 754 switch (phdr->p_type) { 755 case PT_LOAD: 756 if (nsegs == MAXSEGS) { 757 link_elf_error(filename, "Too many sections"); 758 error = ENOEXEC; 759 goto out; 760 } 761 /* 762 * XXX: We just trust they come in right order ?? 763 */ 764 segs[nsegs] = phdr; 765 ++nsegs; 766 break; 767 768 case PT_PHDR: 769 phphdr = phdr; 770 break; 771 772 case PT_DYNAMIC: 773 phdyn = phdr; 774 break; 775 776 case PT_INTERP: 777 error = ENOSYS; 778 goto out; 779 } 780 781 ++phdr; 782 } 783 if (phdyn == NULL) { 784 link_elf_error(filename, "Object is not dynamically-linked"); 785 error = ENOEXEC; 786 goto out; 787 } 788 if (nsegs == 0) { 789 link_elf_error(filename, "No sections"); 790 error = ENOEXEC; 791 goto out; 792 } 793 794 /* 795 * Allocate the entire address space of the object, to stake 796 * out our contiguous region, and to establish the base 797 * address for relocation. 798 */ 799 base_offset = trunc_page(segs[0]->p_offset); 800 base_vaddr = trunc_page(segs[0]->p_vaddr); 801 base_vlimit = round_page(segs[nsegs - 1]->p_vaddr + 802 segs[nsegs - 1]->p_memsz); 803 mapsize = base_vlimit - base_vaddr; 804 805 lf = linker_make_file(filename, &link_elf_class); 806 if (lf == NULL) { 807 error = ENOMEM; 808 goto out; 809 } 810 811 ef = (elf_file_t) lf; 812 #ifdef SPARSE_MAPPING 813 ef->object = vm_object_allocate(OBJT_DEFAULT, mapsize >> PAGE_SHIFT); 814 if (ef->object == NULL) { 815 error = ENOMEM; 816 goto out; 817 } 818 ef->address = (caddr_t) vm_map_min(kernel_map); 819 error = vm_map_find(kernel_map, ef->object, 0, 820 (vm_offset_t *) &ef->address, mapsize, 1, 821 VM_PROT_ALL, VM_PROT_ALL, 0); 822 if (error != 0) { 823 vm_object_deallocate(ef->object); 824 ef->object = 0; 825 goto out; 826 } 827 #else 828 ef->address = malloc(mapsize, M_LINKER, M_WAITOK); 829 #endif 830 mapbase = ef->address; 831 832 /* 833 * Read the text and data sections and zero the bss. 834 */ 835 for (i = 0; i < nsegs; i++) { 836 caddr_t segbase = mapbase + segs[i]->p_vaddr - base_vaddr; 837 error = vn_rdwr(UIO_READ, nd.ni_vp, 838 segbase, segs[i]->p_filesz, segs[i]->p_offset, 839 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 840 &resid, td); 841 if (error != 0) 842 goto out; 843 bzero(segbase + segs[i]->p_filesz, 844 segs[i]->p_memsz - segs[i]->p_filesz); 845 846 #ifdef SPARSE_MAPPING 847 /* 848 * Wire down the pages 849 */ 850 error = vm_map_wire(kernel_map, 851 (vm_offset_t) segbase, 852 (vm_offset_t) segbase + segs[i]->p_memsz, 853 VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES); 854 if (error != KERN_SUCCESS) { 855 error = ENOMEM; 856 goto out; 857 } 858 #endif 859 } 860 861 #ifdef GPROF 862 /* Update profiling information with the new text segment. */ 863 mtx_lock(&Giant); 864 kmupetext((uintfptr_t)(mapbase + segs[0]->p_vaddr - base_vaddr + 865 segs[0]->p_memsz)); 866 mtx_unlock(&Giant); 867 #endif 868 869 ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr); 870 871 lf->address = ef->address; 872 lf->size = mapsize; 873 874 error = parse_dynamic(ef); 875 if (error != 0) 876 goto out; 877 error = parse_dpcpu(ef); 878 if (error != 0) 879 goto out; 880 #ifdef VIMAGE 881 error = parse_vnet(ef); 882 if (error != 0) 883 goto out; 884 #endif 885 link_elf_reloc_local(lf); 886 887 VOP_UNLOCK(nd.ni_vp, 0); 888 error = linker_load_dependencies(lf); 889 vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY); 890 if (error != 0) 891 goto out; 892 #if 0 /* this will be more trouble than it's worth for now */ 893 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) { 894 if (dp->d_tag != DT_NEEDED) 895 continue; 896 modname = ef->strtab + dp->d_un.d_val; 897 error = linker_load_module(modname, lf); 898 if (error != 0) 899 goto out; 900 } 901 #endif 902 error = relocate_file(ef); 903 if (error != 0) 904 goto out; 905 906 /* 907 * Try and load the symbol table if it's present. (you can 908 * strip it!) 909 */ 910 nbytes = hdr->e_shnum * hdr->e_shentsize; 911 if (nbytes == 0 || hdr->e_shoff == 0) 912 goto nosyms; 913 shdr = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO); 914 error = vn_rdwr(UIO_READ, nd.ni_vp, 915 (caddr_t)shdr, nbytes, hdr->e_shoff, 916 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 917 &resid, td); 918 if (error != 0) 919 goto out; 920 symtabindex = -1; 921 symstrindex = -1; 922 for (i = 0; i < hdr->e_shnum; i++) { 923 if (shdr[i].sh_type == SHT_SYMTAB) { 924 symtabindex = i; 925 symstrindex = shdr[i].sh_link; 926 } 927 } 928 if (symtabindex < 0 || symstrindex < 0) 929 goto nosyms; 930 931 symcnt = shdr[symtabindex].sh_size; 932 ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK); 933 strcnt = shdr[symstrindex].sh_size; 934 ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK); 935 936 error = vn_rdwr(UIO_READ, nd.ni_vp, 937 ef->symbase, symcnt, shdr[symtabindex].sh_offset, 938 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 939 &resid, td); 940 if (error != 0) 941 goto out; 942 error = vn_rdwr(UIO_READ, nd.ni_vp, 943 ef->strbase, strcnt, shdr[symstrindex].sh_offset, 944 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 945 &resid, td); 946 if (error != 0) 947 goto out; 948 949 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym); 950 ef->ddbsymtab = (const Elf_Sym *)ef->symbase; 951 ef->ddbstrcnt = strcnt; 952 ef->ddbstrtab = ef->strbase; 953 954 nosyms: 955 error = link_elf_link_common_finish(lf); 956 if (error != 0) 957 goto out; 958 959 *result = lf; 960 961 out: 962 VOP_UNLOCK(nd.ni_vp, 0); 963 vn_close(nd.ni_vp, FREAD, td->td_ucred, td); 964 VFS_UNLOCK_GIANT(vfslocked); 965 if (error != 0 && lf != NULL) 966 linker_file_unload(lf, LINKER_UNLOAD_FORCE); 967 if (shdr != NULL) 968 free(shdr, M_LINKER); 969 if (firstpage != NULL) 970 free(firstpage, M_LINKER); 971 972 return (error); 973 } 974 975 Elf_Addr 976 elf_relocaddr(linker_file_t lf, Elf_Addr x) 977 { 978 elf_file_t ef; 979 980 ef = (elf_file_t)lf; 981 if (x >= ef->pcpu_start && x < ef->pcpu_stop) 982 return ((x - ef->pcpu_start) + ef->pcpu_base); 983 #ifdef VIMAGE 984 if (x >= ef->vnet_start && x < ef->vnet_stop) 985 return ((x - ef->vnet_start) + ef->vnet_base); 986 #endif 987 return (x); 988 } 989 990 991 static void 992 link_elf_unload_file(linker_file_t file) 993 { 994 elf_file_t ef = (elf_file_t) file; 995 996 if (ef->pcpu_base != 0) { 997 dpcpu_free((void *)ef->pcpu_base, 998 ef->pcpu_stop - ef->pcpu_start); 999 } 1000 #ifdef VIMAGE 1001 if (ef->vnet_base != 0) { 1002 vnet_data_free((void *)ef->vnet_base, 1003 ef->vnet_stop - ef->vnet_start); 1004 } 1005 #endif 1006 #ifdef GDB 1007 if (ef->gdb.l_ld != NULL) { 1008 GDB_STATE(RT_DELETE); 1009 free((void *)(uintptr_t)ef->gdb.l_name, M_LINKER); 1010 link_elf_delete_gdb(&ef->gdb); 1011 GDB_STATE(RT_CONSISTENT); 1012 } 1013 #endif 1014 1015 /* Notify MD code that a module is being unloaded. */ 1016 elf_cpu_unload_file(file); 1017 1018 if (ef->preloaded) { 1019 link_elf_unload_preload(file); 1020 return; 1021 } 1022 1023 #ifdef SPARSE_MAPPING 1024 if (ef->object != NULL) { 1025 vm_map_remove(kernel_map, (vm_offset_t) ef->address, 1026 (vm_offset_t) ef->address 1027 + (ef->object->size << PAGE_SHIFT)); 1028 } 1029 #else 1030 if (ef->address != NULL) 1031 free(ef->address, M_LINKER); 1032 #endif 1033 if (ef->symbase != NULL) 1034 free(ef->symbase, M_LINKER); 1035 if (ef->strbase != NULL) 1036 free(ef->strbase, M_LINKER); 1037 if (ef->ctftab != NULL) 1038 free(ef->ctftab, M_LINKER); 1039 if (ef->ctfoff != NULL) 1040 free(ef->ctfoff, M_LINKER); 1041 if (ef->typoff != NULL) 1042 free(ef->typoff, M_LINKER); 1043 } 1044 1045 static void 1046 link_elf_unload_preload(linker_file_t file) 1047 { 1048 if (file->filename != NULL) 1049 preload_delete_name(file->filename); 1050 } 1051 1052 static const char * 1053 symbol_name(elf_file_t ef, Elf_Size r_info) 1054 { 1055 const Elf_Sym *ref; 1056 1057 if (ELF_R_SYM(r_info)) { 1058 ref = ef->symtab + ELF_R_SYM(r_info); 1059 return (ef->strtab + ref->st_name); 1060 } 1061 return (NULL); 1062 } 1063 1064 static int 1065 relocate_file(elf_file_t ef) 1066 { 1067 const Elf_Rel *rellim; 1068 const Elf_Rel *rel; 1069 const Elf_Rela *relalim; 1070 const Elf_Rela *rela; 1071 const char *symname; 1072 1073 /* Perform relocations without addend if there are any: */ 1074 rel = ef->rel; 1075 if (rel != NULL) { 1076 rellim = (const Elf_Rel *) 1077 ((const char *)ef->rel + ef->relsize); 1078 while (rel < rellim) { 1079 if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rel, 1080 ELF_RELOC_REL, elf_lookup)) { 1081 symname = symbol_name(ef, rel->r_info); 1082 printf("link_elf: symbol %s undefined\n", symname); 1083 return (ENOENT); 1084 } 1085 rel++; 1086 } 1087 } 1088 1089 /* Perform relocations with addend if there are any: */ 1090 rela = ef->rela; 1091 if (rela != NULL) { 1092 relalim = (const Elf_Rela *) 1093 ((const char *)ef->rela + ef->relasize); 1094 while (rela < relalim) { 1095 if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rela, 1096 ELF_RELOC_RELA, elf_lookup)) { 1097 symname = symbol_name(ef, rela->r_info); 1098 printf("link_elf: symbol %s undefined\n", 1099 symname); 1100 return (ENOENT); 1101 } 1102 rela++; 1103 } 1104 } 1105 1106 /* Perform PLT relocations without addend if there are any: */ 1107 rel = ef->pltrel; 1108 if (rel != NULL) { 1109 rellim = (const Elf_Rel *) 1110 ((const char *)ef->pltrel + ef->pltrelsize); 1111 while (rel < rellim) { 1112 if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rel, 1113 ELF_RELOC_REL, elf_lookup)) { 1114 symname = symbol_name(ef, rel->r_info); 1115 printf("link_elf: symbol %s undefined\n", 1116 symname); 1117 return (ENOENT); 1118 } 1119 rel++; 1120 } 1121 } 1122 1123 /* Perform relocations with addend if there are any: */ 1124 rela = ef->pltrela; 1125 if (rela != NULL) { 1126 relalim = (const Elf_Rela *) 1127 ((const char *)ef->pltrela + ef->pltrelasize); 1128 while (rela < relalim) { 1129 if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rela, 1130 ELF_RELOC_RELA, elf_lookup)) { 1131 symname = symbol_name(ef, rela->r_info); 1132 printf("link_elf: symbol %s undefined\n", 1133 symname); 1134 return (ENOENT); 1135 } 1136 rela++; 1137 } 1138 } 1139 1140 return (0); 1141 } 1142 1143 /* 1144 * Hash function for symbol table lookup. Don't even think about changing 1145 * this. It is specified by the System V ABI. 1146 */ 1147 static unsigned long 1148 elf_hash(const char *name) 1149 { 1150 const unsigned char *p = (const unsigned char *) name; 1151 unsigned long h = 0; 1152 unsigned long g; 1153 1154 while (*p != '\0') { 1155 h = (h << 4) + *p++; 1156 if ((g = h & 0xf0000000) != 0) 1157 h ^= g >> 24; 1158 h &= ~g; 1159 } 1160 return (h); 1161 } 1162 1163 static int 1164 link_elf_lookup_symbol(linker_file_t lf, const char* name, c_linker_sym_t* sym) 1165 { 1166 elf_file_t ef = (elf_file_t) lf; 1167 unsigned long symnum; 1168 const Elf_Sym* symp; 1169 const char *strp; 1170 unsigned long hash; 1171 int i; 1172 1173 /* If we don't have a hash, bail. */ 1174 if (ef->buckets == NULL || ef->nbuckets == 0) { 1175 printf("link_elf_lookup_symbol: missing symbol hash table\n"); 1176 return (ENOENT); 1177 } 1178 1179 /* First, search hashed global symbols */ 1180 hash = elf_hash(name); 1181 symnum = ef->buckets[hash % ef->nbuckets]; 1182 1183 while (symnum != STN_UNDEF) { 1184 if (symnum >= ef->nchains) { 1185 printf("%s: corrupt symbol table\n", __func__); 1186 return (ENOENT); 1187 } 1188 1189 symp = ef->symtab + symnum; 1190 if (symp->st_name == 0) { 1191 printf("%s: corrupt symbol table\n", __func__); 1192 return (ENOENT); 1193 } 1194 1195 strp = ef->strtab + symp->st_name; 1196 1197 if (strcmp(name, strp) == 0) { 1198 if (symp->st_shndx != SHN_UNDEF || 1199 (symp->st_value != 0 && 1200 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) { 1201 *sym = (c_linker_sym_t) symp; 1202 return (0); 1203 } 1204 return (ENOENT); 1205 } 1206 1207 symnum = ef->chains[symnum]; 1208 } 1209 1210 /* If we have not found it, look at the full table (if loaded) */ 1211 if (ef->symtab == ef->ddbsymtab) 1212 return (ENOENT); 1213 1214 /* Exhaustive search */ 1215 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1216 strp = ef->ddbstrtab + symp->st_name; 1217 if (strcmp(name, strp) == 0) { 1218 if (symp->st_shndx != SHN_UNDEF || 1219 (symp->st_value != 0 && 1220 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) { 1221 *sym = (c_linker_sym_t) symp; 1222 return (0); 1223 } 1224 return (ENOENT); 1225 } 1226 } 1227 1228 return (ENOENT); 1229 } 1230 1231 static int 1232 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, 1233 linker_symval_t *symval) 1234 { 1235 elf_file_t ef = (elf_file_t) lf; 1236 const Elf_Sym* es = (const Elf_Sym*) sym; 1237 1238 if (es >= ef->symtab && es < (ef->symtab + ef->nchains)) { 1239 symval->name = ef->strtab + es->st_name; 1240 symval->value = (caddr_t) ef->address + es->st_value; 1241 symval->size = es->st_size; 1242 return (0); 1243 } 1244 if (ef->symtab == ef->ddbsymtab) 1245 return (ENOENT); 1246 if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) { 1247 symval->name = ef->ddbstrtab + es->st_name; 1248 symval->value = (caddr_t) ef->address + es->st_value; 1249 symval->size = es->st_size; 1250 return (0); 1251 } 1252 return (ENOENT); 1253 } 1254 1255 static int 1256 link_elf_search_symbol(linker_file_t lf, caddr_t value, 1257 c_linker_sym_t *sym, long *diffp) 1258 { 1259 elf_file_t ef = (elf_file_t) lf; 1260 u_long off = (uintptr_t) (void *) value; 1261 u_long diff = off; 1262 u_long st_value; 1263 const Elf_Sym* es; 1264 const Elf_Sym* best = 0; 1265 int i; 1266 1267 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) { 1268 if (es->st_name == 0) 1269 continue; 1270 st_value = es->st_value + (uintptr_t) (void *) ef->address; 1271 if (off >= st_value) { 1272 if (off - st_value < diff) { 1273 diff = off - st_value; 1274 best = es; 1275 if (diff == 0) 1276 break; 1277 } else if (off - st_value == diff) { 1278 best = es; 1279 } 1280 } 1281 } 1282 if (best == 0) 1283 *diffp = off; 1284 else 1285 *diffp = diff; 1286 *sym = (c_linker_sym_t) best; 1287 1288 return (0); 1289 } 1290 1291 /* 1292 * Look up a linker set on an ELF system. 1293 */ 1294 static int 1295 link_elf_lookup_set(linker_file_t lf, const char *name, 1296 void ***startp, void ***stopp, int *countp) 1297 { 1298 c_linker_sym_t sym; 1299 linker_symval_t symval; 1300 char *setsym; 1301 void **start, **stop; 1302 int len, error = 0, count; 1303 1304 len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */ 1305 setsym = malloc(len, M_LINKER, M_WAITOK); 1306 1307 /* get address of first entry */ 1308 snprintf(setsym, len, "%s%s", "__start_set_", name); 1309 error = link_elf_lookup_symbol(lf, setsym, &sym); 1310 if (error != 0) 1311 goto out; 1312 link_elf_symbol_values(lf, sym, &symval); 1313 if (symval.value == 0) { 1314 error = ESRCH; 1315 goto out; 1316 } 1317 start = (void **)symval.value; 1318 1319 /* get address of last entry */ 1320 snprintf(setsym, len, "%s%s", "__stop_set_", name); 1321 error = link_elf_lookup_symbol(lf, setsym, &sym); 1322 if (error != 0) 1323 goto out; 1324 link_elf_symbol_values(lf, sym, &symval); 1325 if (symval.value == 0) { 1326 error = ESRCH; 1327 goto out; 1328 } 1329 stop = (void **)symval.value; 1330 1331 /* and the number of entries */ 1332 count = stop - start; 1333 1334 /* and copy out */ 1335 if (startp != NULL) 1336 *startp = start; 1337 if (stopp != NULL) 1338 *stopp = stop; 1339 if (countp != NULL) 1340 *countp = count; 1341 1342 out: 1343 free(setsym, M_LINKER); 1344 return (error); 1345 } 1346 1347 static int 1348 link_elf_each_function_name(linker_file_t file, 1349 int (*callback)(const char *, void *), void *opaque) 1350 { 1351 elf_file_t ef = (elf_file_t)file; 1352 const Elf_Sym *symp; 1353 int i, error; 1354 1355 /* Exhaustive search */ 1356 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1357 if (symp->st_value != 0 && 1358 ELF_ST_TYPE(symp->st_info) == STT_FUNC) { 1359 error = callback(ef->ddbstrtab + symp->st_name, opaque); 1360 if (error != 0) 1361 return (error); 1362 } 1363 } 1364 return (0); 1365 } 1366 1367 static int 1368 link_elf_each_function_nameval(linker_file_t file, 1369 linker_function_nameval_callback_t callback, void *opaque) 1370 { 1371 linker_symval_t symval; 1372 elf_file_t ef = (elf_file_t)file; 1373 const Elf_Sym* symp; 1374 int i, error; 1375 1376 /* Exhaustive search */ 1377 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1378 if (symp->st_value != 0 && 1379 ELF_ST_TYPE(symp->st_info) == STT_FUNC) { 1380 error = link_elf_symbol_values(file, 1381 (c_linker_sym_t) symp, &symval); 1382 if (error != 0) 1383 return (error); 1384 error = callback(file, i, &symval, opaque); 1385 if (error != 0) 1386 return (error); 1387 } 1388 } 1389 return (0); 1390 } 1391 1392 #ifdef __ia64__ 1393 /* 1394 * Each KLD has its own GP. The GP value for each load module is given by 1395 * DT_PLTGOT on ia64. We need GP to construct function descriptors, but 1396 * don't have direct access to the ELF file structure. The link_elf_get_gp() 1397 * function returns the GP given a pointer to a generic linker file struct. 1398 */ 1399 Elf_Addr 1400 link_elf_get_gp(linker_file_t lf) 1401 { 1402 elf_file_t ef = (elf_file_t)lf; 1403 return ((Elf_Addr)ef->got); 1404 } 1405 #endif 1406 1407 const Elf_Sym * 1408 elf_get_sym(linker_file_t lf, Elf_Size symidx) 1409 { 1410 elf_file_t ef = (elf_file_t)lf; 1411 1412 if (symidx >= ef->nchains) 1413 return (NULL); 1414 return (ef->symtab + symidx); 1415 } 1416 1417 const char * 1418 elf_get_symname(linker_file_t lf, Elf_Size symidx) 1419 { 1420 elf_file_t ef = (elf_file_t)lf; 1421 const Elf_Sym *sym; 1422 1423 if (symidx >= ef->nchains) 1424 return (NULL); 1425 sym = ef->symtab + symidx; 1426 return (ef->strtab + sym->st_name); 1427 } 1428 1429 /* 1430 * Symbol lookup function that can be used when the symbol index is known (ie 1431 * in relocations). It uses the symbol index instead of doing a fully fledged 1432 * hash table based lookup when such is valid. For example for local symbols. 1433 * This is not only more efficient, it's also more correct. It's not always 1434 * the case that the symbol can be found through the hash table. 1435 */ 1436 static Elf_Addr 1437 elf_lookup(linker_file_t lf, Elf_Size symidx, int deps) 1438 { 1439 elf_file_t ef = (elf_file_t)lf; 1440 const Elf_Sym *sym; 1441 const char *symbol; 1442 1443 /* Don't even try to lookup the symbol if the index is bogus. */ 1444 if (symidx >= ef->nchains) 1445 return (0); 1446 1447 sym = ef->symtab + symidx; 1448 1449 /* 1450 * Don't do a full lookup when the symbol is local. It may even 1451 * fail because it may not be found through the hash table. 1452 */ 1453 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) { 1454 /* Force lookup failure when we have an insanity. */ 1455 if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0) 1456 return (0); 1457 return ((Elf_Addr)ef->address + sym->st_value); 1458 } 1459 1460 /* 1461 * XXX we can avoid doing a hash table based lookup for global 1462 * symbols as well. This however is not always valid, so we'll 1463 * just do it the hard way for now. Performance tweaks can 1464 * always be added. 1465 */ 1466 1467 symbol = ef->strtab + sym->st_name; 1468 1469 /* Force a lookup failure if the symbol name is bogus. */ 1470 if (*symbol == 0) 1471 return (0); 1472 1473 return ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps)); 1474 } 1475 1476 static void 1477 link_elf_reloc_local(linker_file_t lf) 1478 { 1479 const Elf_Rel *rellim; 1480 const Elf_Rel *rel; 1481 const Elf_Rela *relalim; 1482 const Elf_Rela *rela; 1483 elf_file_t ef = (elf_file_t)lf; 1484 1485 /* Perform relocations without addend if there are any: */ 1486 if ((rel = ef->rel) != NULL) { 1487 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize); 1488 while (rel < rellim) { 1489 elf_reloc_local(lf, (Elf_Addr)ef->address, rel, 1490 ELF_RELOC_REL, elf_lookup); 1491 rel++; 1492 } 1493 } 1494 1495 /* Perform relocations with addend if there are any: */ 1496 if ((rela = ef->rela) != NULL) { 1497 relalim = (const Elf_Rela *) 1498 ((const char *)ef->rela + ef->relasize); 1499 while (rela < relalim) { 1500 elf_reloc_local(lf, (Elf_Addr)ef->address, rela, 1501 ELF_RELOC_RELA, elf_lookup); 1502 rela++; 1503 } 1504 } 1505 } 1506 1507 static long 1508 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab) 1509 { 1510 elf_file_t ef = (elf_file_t)lf; 1511 1512 *symtab = ef->ddbsymtab; 1513 1514 if (*symtab == NULL) 1515 return (0); 1516 1517 return (ef->ddbsymcnt); 1518 } 1519 1520 static long 1521 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab) 1522 { 1523 elf_file_t ef = (elf_file_t)lf; 1524 1525 *strtab = ef->ddbstrtab; 1526 1527 if (*strtab == NULL) 1528 return (0); 1529 1530 return (ef->ddbstrcnt); 1531 }
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