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_obj.c
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1 /*- 2 * Copyright (c) 1998-2000 Doug Rabson 3 * Copyright (c) 2004 Peter Wemm 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 */ 27 28 #include <sys/cdefs.h> 29 __FBSDID("$FreeBSD: releng/11.2/sys/kern/link_elf_obj.c 333720 2018-05-17 15:24:53Z kib $"); 30 31 #include "opt_ddb.h" 32 33 #include <sys/param.h> 34 #include <sys/systm.h> 35 #include <sys/kernel.h> 36 #include <sys/lock.h> 37 #include <sys/malloc.h> 38 #include <sys/mutex.h> 39 #include <sys/mount.h> 40 #include <sys/proc.h> 41 #include <sys/namei.h> 42 #include <sys/fcntl.h> 43 #include <sys/vnode.h> 44 #include <sys/linker.h> 45 46 #include <machine/elf.h> 47 48 #include <net/vnet.h> 49 50 #include <security/mac/mac_framework.h> 51 52 #include <vm/vm.h> 53 #include <vm/vm_param.h> 54 #include <vm/vm_object.h> 55 #include <vm/vm_kern.h> 56 #include <vm/vm_extern.h> 57 #include <vm/pmap.h> 58 #include <vm/vm_map.h> 59 60 #include <sys/link_elf.h> 61 62 #ifdef DDB_CTF 63 #include <sys/zlib.h> 64 #endif 65 66 #include "linker_if.h" 67 68 typedef struct { 69 void *addr; 70 Elf_Off size; 71 int flags; 72 int sec; /* Original section */ 73 char *name; 74 } Elf_progent; 75 76 typedef struct { 77 Elf_Rel *rel; 78 int nrel; 79 int sec; 80 } Elf_relent; 81 82 typedef struct { 83 Elf_Rela *rela; 84 int nrela; 85 int sec; 86 } Elf_relaent; 87 88 89 typedef struct elf_file { 90 struct linker_file lf; /* Common fields */ 91 92 int preloaded; 93 caddr_t address; /* Relocation address */ 94 vm_object_t object; /* VM object to hold file pages */ 95 Elf_Shdr *e_shdr; 96 97 Elf_progent *progtab; 98 int nprogtab; 99 100 Elf_relaent *relatab; 101 int nrelatab; 102 103 Elf_relent *reltab; 104 int nreltab; 105 106 Elf_Sym *ddbsymtab; /* The symbol table we are using */ 107 long ddbsymcnt; /* Number of symbols */ 108 caddr_t ddbstrtab; /* String table */ 109 long ddbstrcnt; /* number of bytes in string table */ 110 111 caddr_t shstrtab; /* Section name string table */ 112 long shstrcnt; /* number of bytes in string table */ 113 114 caddr_t ctftab; /* CTF table */ 115 long ctfcnt; /* number of bytes in CTF table */ 116 caddr_t ctfoff; /* CTF offset table */ 117 caddr_t typoff; /* Type offset table */ 118 long typlen; /* Number of type entries. */ 119 120 } *elf_file_t; 121 122 #include <kern/kern_ctf.c> 123 124 static int link_elf_link_preload(linker_class_t cls, 125 const char *, linker_file_t *); 126 static int link_elf_link_preload_finish(linker_file_t); 127 static int link_elf_load_file(linker_class_t, const char *, linker_file_t *); 128 static int link_elf_lookup_symbol(linker_file_t, const char *, 129 c_linker_sym_t *); 130 static int link_elf_symbol_values(linker_file_t, c_linker_sym_t, 131 linker_symval_t *); 132 static int link_elf_search_symbol(linker_file_t, caddr_t value, 133 c_linker_sym_t *sym, long *diffp); 134 135 static void link_elf_unload_file(linker_file_t); 136 static int link_elf_lookup_set(linker_file_t, const char *, 137 void ***, void ***, int *); 138 static int link_elf_each_function_name(linker_file_t, 139 int (*)(const char *, void *), void *); 140 static int link_elf_each_function_nameval(linker_file_t, 141 linker_function_nameval_callback_t, 142 void *); 143 static int link_elf_reloc_local(linker_file_t); 144 static long link_elf_symtab_get(linker_file_t, const Elf_Sym **); 145 static long link_elf_strtab_get(linker_file_t, caddr_t *); 146 147 static int elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps, 148 Elf_Addr *); 149 150 static kobj_method_t link_elf_methods[] = { 151 KOBJMETHOD(linker_lookup_symbol, link_elf_lookup_symbol), 152 KOBJMETHOD(linker_symbol_values, link_elf_symbol_values), 153 KOBJMETHOD(linker_search_symbol, link_elf_search_symbol), 154 KOBJMETHOD(linker_unload, link_elf_unload_file), 155 KOBJMETHOD(linker_load_file, link_elf_load_file), 156 KOBJMETHOD(linker_link_preload, link_elf_link_preload), 157 KOBJMETHOD(linker_link_preload_finish, link_elf_link_preload_finish), 158 KOBJMETHOD(linker_lookup_set, link_elf_lookup_set), 159 KOBJMETHOD(linker_each_function_name, link_elf_each_function_name), 160 KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval), 161 KOBJMETHOD(linker_ctf_get, link_elf_ctf_get), 162 KOBJMETHOD(linker_symtab_get, link_elf_symtab_get), 163 KOBJMETHOD(linker_strtab_get, link_elf_strtab_get), 164 { 0, 0 } 165 }; 166 167 static struct linker_class link_elf_class = { 168 #if ELF_TARG_CLASS == ELFCLASS32 169 "elf32_obj", 170 #else 171 "elf64_obj", 172 #endif 173 link_elf_methods, sizeof(struct elf_file) 174 }; 175 176 static int relocate_file(elf_file_t ef); 177 static void elf_obj_cleanup_globals_cache(elf_file_t); 178 179 static void 180 link_elf_error(const char *filename, const char *s) 181 { 182 if (filename == NULL) 183 printf("kldload: %s\n", s); 184 else 185 printf("kldload: %s: %s\n", filename, s); 186 } 187 188 static void 189 link_elf_init(void *arg) 190 { 191 192 linker_add_class(&link_elf_class); 193 } 194 195 SYSINIT(link_elf_obj, SI_SUB_KLD, SI_ORDER_SECOND, link_elf_init, 0); 196 197 static int 198 link_elf_link_preload(linker_class_t cls, const char *filename, 199 linker_file_t *result) 200 { 201 Elf_Ehdr *hdr; 202 Elf_Shdr *shdr; 203 Elf_Sym *es; 204 void *modptr, *baseptr, *sizeptr; 205 char *type; 206 elf_file_t ef; 207 linker_file_t lf; 208 Elf_Addr off; 209 int error, i, j, pb, ra, rl, shstrindex, symstrindex, symtabindex; 210 211 /* Look to see if we have the file preloaded */ 212 modptr = preload_search_by_name(filename); 213 if (modptr == NULL) 214 return ENOENT; 215 216 type = (char *)preload_search_info(modptr, MODINFO_TYPE); 217 baseptr = preload_search_info(modptr, MODINFO_ADDR); 218 sizeptr = preload_search_info(modptr, MODINFO_SIZE); 219 hdr = (Elf_Ehdr *)preload_search_info(modptr, MODINFO_METADATA | 220 MODINFOMD_ELFHDR); 221 shdr = (Elf_Shdr *)preload_search_info(modptr, MODINFO_METADATA | 222 MODINFOMD_SHDR); 223 if (type == NULL || (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) 224 " obj module") != 0 && 225 strcmp(type, "elf obj module") != 0)) { 226 return (EFTYPE); 227 } 228 if (baseptr == NULL || sizeptr == NULL || hdr == NULL || 229 shdr == NULL) 230 return (EINVAL); 231 232 lf = linker_make_file(filename, &link_elf_class); 233 if (lf == NULL) 234 return (ENOMEM); 235 236 ef = (elf_file_t)lf; 237 ef->preloaded = 1; 238 ef->address = *(caddr_t *)baseptr; 239 lf->address = *(caddr_t *)baseptr; 240 lf->size = *(size_t *)sizeptr; 241 242 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS || 243 hdr->e_ident[EI_DATA] != ELF_TARG_DATA || 244 hdr->e_ident[EI_VERSION] != EV_CURRENT || 245 hdr->e_version != EV_CURRENT || 246 hdr->e_type != ET_REL || 247 hdr->e_machine != ELF_TARG_MACH) { 248 error = EFTYPE; 249 goto out; 250 } 251 ef->e_shdr = shdr; 252 253 /* Scan the section header for information and table sizing. */ 254 symtabindex = -1; 255 symstrindex = -1; 256 for (i = 0; i < hdr->e_shnum; i++) { 257 switch (shdr[i].sh_type) { 258 case SHT_PROGBITS: 259 case SHT_NOBITS: 260 #ifdef __amd64__ 261 case SHT_X86_64_UNWIND: 262 #endif 263 /* Ignore sections not loaded by the loader. */ 264 if (shdr[i].sh_addr == 0) 265 break; 266 ef->nprogtab++; 267 break; 268 case SHT_SYMTAB: 269 symtabindex = i; 270 symstrindex = shdr[i].sh_link; 271 break; 272 case SHT_REL: 273 /* 274 * Ignore relocation tables for sections not 275 * loaded by the loader. 276 */ 277 if (shdr[shdr[i].sh_info].sh_addr == 0) 278 break; 279 ef->nreltab++; 280 break; 281 case SHT_RELA: 282 if (shdr[shdr[i].sh_info].sh_addr == 0) 283 break; 284 ef->nrelatab++; 285 break; 286 } 287 } 288 289 shstrindex = hdr->e_shstrndx; 290 if (ef->nprogtab == 0 || symstrindex < 0 || 291 symstrindex >= hdr->e_shnum || 292 shdr[symstrindex].sh_type != SHT_STRTAB || shstrindex == 0 || 293 shstrindex >= hdr->e_shnum || 294 shdr[shstrindex].sh_type != SHT_STRTAB) { 295 printf("%s: bad/missing section headers\n", filename); 296 error = ENOEXEC; 297 goto out; 298 } 299 300 /* Allocate space for tracking the load chunks */ 301 if (ef->nprogtab != 0) 302 ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab), 303 M_LINKER, M_WAITOK | M_ZERO); 304 if (ef->nreltab != 0) 305 ef->reltab = malloc(ef->nreltab * sizeof(*ef->reltab), 306 M_LINKER, M_WAITOK | M_ZERO); 307 if (ef->nrelatab != 0) 308 ef->relatab = malloc(ef->nrelatab * sizeof(*ef->relatab), 309 M_LINKER, M_WAITOK | M_ZERO); 310 if ((ef->nprogtab != 0 && ef->progtab == NULL) || 311 (ef->nreltab != 0 && ef->reltab == NULL) || 312 (ef->nrelatab != 0 && ef->relatab == NULL)) { 313 error = ENOMEM; 314 goto out; 315 } 316 317 /* XXX, relocate the sh_addr fields saved by the loader. */ 318 off = 0; 319 for (i = 0; i < hdr->e_shnum; i++) { 320 if (shdr[i].sh_addr != 0 && (off == 0 || shdr[i].sh_addr < off)) 321 off = shdr[i].sh_addr; 322 } 323 for (i = 0; i < hdr->e_shnum; i++) { 324 if (shdr[i].sh_addr != 0) 325 shdr[i].sh_addr = shdr[i].sh_addr - off + 326 (Elf_Addr)ef->address; 327 } 328 329 ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym); 330 ef->ddbsymtab = (Elf_Sym *)shdr[symtabindex].sh_addr; 331 ef->ddbstrcnt = shdr[symstrindex].sh_size; 332 ef->ddbstrtab = (char *)shdr[symstrindex].sh_addr; 333 ef->shstrcnt = shdr[shstrindex].sh_size; 334 ef->shstrtab = (char *)shdr[shstrindex].sh_addr; 335 336 /* Now fill out progtab and the relocation tables. */ 337 pb = 0; 338 rl = 0; 339 ra = 0; 340 for (i = 0; i < hdr->e_shnum; i++) { 341 switch (shdr[i].sh_type) { 342 case SHT_PROGBITS: 343 case SHT_NOBITS: 344 #ifdef __amd64__ 345 case SHT_X86_64_UNWIND: 346 #endif 347 if (shdr[i].sh_addr == 0) 348 break; 349 ef->progtab[pb].addr = (void *)shdr[i].sh_addr; 350 if (shdr[i].sh_type == SHT_PROGBITS) 351 ef->progtab[pb].name = "<<PROGBITS>>"; 352 #ifdef __amd64__ 353 else if (shdr[i].sh_type == SHT_X86_64_UNWIND) 354 ef->progtab[pb].name = "<<UNWIND>>"; 355 #endif 356 else 357 ef->progtab[pb].name = "<<NOBITS>>"; 358 ef->progtab[pb].size = shdr[i].sh_size; 359 ef->progtab[pb].sec = i; 360 if (ef->shstrtab && shdr[i].sh_name != 0) 361 ef->progtab[pb].name = 362 ef->shstrtab + shdr[i].sh_name; 363 if (ef->progtab[pb].name != NULL && 364 !strcmp(ef->progtab[pb].name, DPCPU_SETNAME)) { 365 void *dpcpu; 366 367 dpcpu = dpcpu_alloc(shdr[i].sh_size); 368 if (dpcpu == NULL) { 369 error = ENOSPC; 370 goto out; 371 } 372 memcpy(dpcpu, ef->progtab[pb].addr, 373 ef->progtab[pb].size); 374 dpcpu_copy(dpcpu, shdr[i].sh_size); 375 ef->progtab[pb].addr = dpcpu; 376 #ifdef VIMAGE 377 } else if (ef->progtab[pb].name != NULL && 378 !strcmp(ef->progtab[pb].name, VNET_SETNAME)) { 379 void *vnet_data; 380 381 vnet_data = vnet_data_alloc(shdr[i].sh_size); 382 if (vnet_data == NULL) { 383 error = ENOSPC; 384 goto out; 385 } 386 memcpy(vnet_data, ef->progtab[pb].addr, 387 ef->progtab[pb].size); 388 vnet_data_copy(vnet_data, shdr[i].sh_size); 389 ef->progtab[pb].addr = vnet_data; 390 #endif 391 } else if (ef->progtab[pb].name != NULL && 392 !strcmp(ef->progtab[pb].name, ".ctors")) { 393 lf->ctors_addr = ef->progtab[pb].addr; 394 lf->ctors_size = shdr[i].sh_size; 395 } 396 397 /* Update all symbol values with the offset. */ 398 for (j = 0; j < ef->ddbsymcnt; j++) { 399 es = &ef->ddbsymtab[j]; 400 if (es->st_shndx != i) 401 continue; 402 es->st_value += (Elf_Addr)ef->progtab[pb].addr; 403 } 404 pb++; 405 break; 406 case SHT_REL: 407 if (shdr[shdr[i].sh_info].sh_addr == 0) 408 break; 409 ef->reltab[rl].rel = (Elf_Rel *)shdr[i].sh_addr; 410 ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel); 411 ef->reltab[rl].sec = shdr[i].sh_info; 412 rl++; 413 break; 414 case SHT_RELA: 415 if (shdr[shdr[i].sh_info].sh_addr == 0) 416 break; 417 ef->relatab[ra].rela = (Elf_Rela *)shdr[i].sh_addr; 418 ef->relatab[ra].nrela = 419 shdr[i].sh_size / sizeof(Elf_Rela); 420 ef->relatab[ra].sec = shdr[i].sh_info; 421 ra++; 422 break; 423 } 424 } 425 if (pb != ef->nprogtab) { 426 printf("%s: lost progbits\n", filename); 427 error = ENOEXEC; 428 goto out; 429 } 430 if (rl != ef->nreltab) { 431 printf("%s: lost reltab\n", filename); 432 error = ENOEXEC; 433 goto out; 434 } 435 if (ra != ef->nrelatab) { 436 printf("%s: lost relatab\n", filename); 437 error = ENOEXEC; 438 goto out; 439 } 440 441 /* Local intra-module relocations */ 442 error = link_elf_reloc_local(lf); 443 if (error != 0) 444 goto out; 445 446 *result = lf; 447 return (0); 448 449 out: 450 /* preload not done this way */ 451 linker_file_unload(lf, LINKER_UNLOAD_FORCE); 452 return (error); 453 } 454 455 static void 456 link_elf_invoke_ctors(caddr_t addr, size_t size) 457 { 458 void (**ctor)(void); 459 size_t i, cnt; 460 461 if (addr == NULL || size == 0) 462 return; 463 cnt = size / sizeof(*ctor); 464 ctor = (void *)addr; 465 for (i = 0; i < cnt; i++) { 466 if (ctor[i] != NULL) 467 (*ctor[i])(); 468 } 469 } 470 471 static int 472 link_elf_link_preload_finish(linker_file_t lf) 473 { 474 elf_file_t ef; 475 int error; 476 477 ef = (elf_file_t)lf; 478 error = relocate_file(ef); 479 if (error) 480 return error; 481 482 /* Notify MD code that a module is being loaded. */ 483 error = elf_cpu_load_file(lf); 484 if (error) 485 return (error); 486 487 /* Invoke .ctors */ 488 link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size); 489 return (0); 490 } 491 492 static int 493 link_elf_load_file(linker_class_t cls, const char *filename, 494 linker_file_t *result) 495 { 496 struct nameidata nd; 497 struct thread *td = curthread; /* XXX */ 498 Elf_Ehdr *hdr; 499 Elf_Shdr *shdr; 500 Elf_Sym *es; 501 int nbytes, i, j; 502 vm_offset_t mapbase; 503 size_t mapsize; 504 int error = 0; 505 ssize_t resid; 506 int flags; 507 elf_file_t ef; 508 linker_file_t lf; 509 int symtabindex; 510 int symstrindex; 511 int shstrindex; 512 int nsym; 513 int pb, rl, ra; 514 int alignmask; 515 516 shdr = NULL; 517 lf = NULL; 518 mapsize = 0; 519 hdr = NULL; 520 521 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td); 522 flags = FREAD; 523 error = vn_open(&nd, &flags, 0, NULL); 524 if (error) 525 return error; 526 NDFREE(&nd, NDF_ONLY_PNBUF); 527 if (nd.ni_vp->v_type != VREG) { 528 error = ENOEXEC; 529 goto out; 530 } 531 #ifdef MAC 532 error = mac_kld_check_load(td->td_ucred, nd.ni_vp); 533 if (error) { 534 goto out; 535 } 536 #endif 537 538 /* Read the elf header from the file. */ 539 hdr = malloc(sizeof(*hdr), M_LINKER, M_WAITOK); 540 error = vn_rdwr(UIO_READ, nd.ni_vp, (void *)hdr, sizeof(*hdr), 0, 541 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 542 &resid, td); 543 if (error) 544 goto out; 545 if (resid != 0){ 546 error = ENOEXEC; 547 goto out; 548 } 549 550 if (!IS_ELF(*hdr)) { 551 error = ENOEXEC; 552 goto out; 553 } 554 555 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS 556 || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) { 557 link_elf_error(filename, "Unsupported file layout"); 558 error = ENOEXEC; 559 goto out; 560 } 561 if (hdr->e_ident[EI_VERSION] != EV_CURRENT 562 || hdr->e_version != EV_CURRENT) { 563 link_elf_error(filename, "Unsupported file version"); 564 error = ENOEXEC; 565 goto out; 566 } 567 if (hdr->e_type != ET_REL) { 568 error = ENOSYS; 569 goto out; 570 } 571 if (hdr->e_machine != ELF_TARG_MACH) { 572 link_elf_error(filename, "Unsupported machine"); 573 error = ENOEXEC; 574 goto out; 575 } 576 577 lf = linker_make_file(filename, &link_elf_class); 578 if (!lf) { 579 error = ENOMEM; 580 goto out; 581 } 582 ef = (elf_file_t) lf; 583 ef->nprogtab = 0; 584 ef->e_shdr = 0; 585 ef->nreltab = 0; 586 ef->nrelatab = 0; 587 588 /* Allocate and read in the section header */ 589 nbytes = hdr->e_shnum * hdr->e_shentsize; 590 if (nbytes == 0 || hdr->e_shoff == 0 || 591 hdr->e_shentsize != sizeof(Elf_Shdr)) { 592 error = ENOEXEC; 593 goto out; 594 } 595 shdr = malloc(nbytes, M_LINKER, M_WAITOK); 596 ef->e_shdr = shdr; 597 error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)shdr, nbytes, hdr->e_shoff, 598 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, &resid, td); 599 if (error) 600 goto out; 601 if (resid) { 602 error = ENOEXEC; 603 goto out; 604 } 605 606 /* Scan the section header for information and table sizing. */ 607 nsym = 0; 608 symtabindex = -1; 609 symstrindex = -1; 610 for (i = 0; i < hdr->e_shnum; i++) { 611 if (shdr[i].sh_size == 0) 612 continue; 613 switch (shdr[i].sh_type) { 614 case SHT_PROGBITS: 615 case SHT_NOBITS: 616 #ifdef __amd64__ 617 case SHT_X86_64_UNWIND: 618 #endif 619 if ((shdr[i].sh_flags & SHF_ALLOC) == 0) 620 break; 621 ef->nprogtab++; 622 break; 623 case SHT_SYMTAB: 624 nsym++; 625 symtabindex = i; 626 symstrindex = shdr[i].sh_link; 627 break; 628 case SHT_REL: 629 /* 630 * Ignore relocation tables for unallocated 631 * sections. 632 */ 633 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0) 634 break; 635 ef->nreltab++; 636 break; 637 case SHT_RELA: 638 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0) 639 break; 640 ef->nrelatab++; 641 break; 642 case SHT_STRTAB: 643 break; 644 } 645 } 646 if (ef->nprogtab == 0) { 647 link_elf_error(filename, "file has no contents"); 648 error = ENOEXEC; 649 goto out; 650 } 651 if (nsym != 1) { 652 /* Only allow one symbol table for now */ 653 link_elf_error(filename, "file has no valid symbol table"); 654 error = ENOEXEC; 655 goto out; 656 } 657 if (symstrindex < 0 || symstrindex > hdr->e_shnum || 658 shdr[symstrindex].sh_type != SHT_STRTAB) { 659 link_elf_error(filename, "file has invalid symbol strings"); 660 error = ENOEXEC; 661 goto out; 662 } 663 664 /* Allocate space for tracking the load chunks */ 665 if (ef->nprogtab != 0) 666 ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab), 667 M_LINKER, M_WAITOK | M_ZERO); 668 if (ef->nreltab != 0) 669 ef->reltab = malloc(ef->nreltab * sizeof(*ef->reltab), 670 M_LINKER, M_WAITOK | M_ZERO); 671 if (ef->nrelatab != 0) 672 ef->relatab = malloc(ef->nrelatab * sizeof(*ef->relatab), 673 M_LINKER, M_WAITOK | M_ZERO); 674 675 if (symtabindex == -1) { 676 link_elf_error(filename, "lost symbol table index"); 677 error = ENOEXEC; 678 goto out; 679 } 680 /* Allocate space for and load the symbol table */ 681 ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym); 682 ef->ddbsymtab = malloc(shdr[symtabindex].sh_size, M_LINKER, M_WAITOK); 683 error = vn_rdwr(UIO_READ, nd.ni_vp, (void *)ef->ddbsymtab, 684 shdr[symtabindex].sh_size, shdr[symtabindex].sh_offset, 685 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 686 &resid, td); 687 if (error) 688 goto out; 689 if (resid != 0){ 690 error = EINVAL; 691 goto out; 692 } 693 694 if (symstrindex == -1) { 695 link_elf_error(filename, "lost symbol string index"); 696 error = ENOEXEC; 697 goto out; 698 } 699 /* Allocate space for and load the symbol strings */ 700 ef->ddbstrcnt = shdr[symstrindex].sh_size; 701 ef->ddbstrtab = malloc(shdr[symstrindex].sh_size, M_LINKER, M_WAITOK); 702 error = vn_rdwr(UIO_READ, nd.ni_vp, ef->ddbstrtab, 703 shdr[symstrindex].sh_size, shdr[symstrindex].sh_offset, 704 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 705 &resid, td); 706 if (error) 707 goto out; 708 if (resid != 0){ 709 error = EINVAL; 710 goto out; 711 } 712 713 /* Do we have a string table for the section names? */ 714 shstrindex = -1; 715 if (hdr->e_shstrndx != 0 && 716 shdr[hdr->e_shstrndx].sh_type == SHT_STRTAB) { 717 shstrindex = hdr->e_shstrndx; 718 ef->shstrcnt = shdr[shstrindex].sh_size; 719 ef->shstrtab = malloc(shdr[shstrindex].sh_size, M_LINKER, 720 M_WAITOK); 721 error = vn_rdwr(UIO_READ, nd.ni_vp, ef->shstrtab, 722 shdr[shstrindex].sh_size, shdr[shstrindex].sh_offset, 723 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 724 &resid, td); 725 if (error) 726 goto out; 727 if (resid != 0){ 728 error = EINVAL; 729 goto out; 730 } 731 } 732 733 /* Size up code/data(progbits) and bss(nobits). */ 734 alignmask = 0; 735 for (i = 0; i < hdr->e_shnum; i++) { 736 if (shdr[i].sh_size == 0) 737 continue; 738 switch (shdr[i].sh_type) { 739 case SHT_PROGBITS: 740 case SHT_NOBITS: 741 #ifdef __amd64__ 742 case SHT_X86_64_UNWIND: 743 #endif 744 if ((shdr[i].sh_flags & SHF_ALLOC) == 0) 745 break; 746 alignmask = shdr[i].sh_addralign - 1; 747 mapsize += alignmask; 748 mapsize &= ~alignmask; 749 mapsize += shdr[i].sh_size; 750 break; 751 } 752 } 753 754 /* 755 * We know how much space we need for the text/data/bss/etc. 756 * This stuff needs to be in a single chunk so that profiling etc 757 * can get the bounds and gdb can associate offsets with modules 758 */ 759 ef->object = vm_object_allocate(OBJT_DEFAULT, 760 round_page(mapsize) >> PAGE_SHIFT); 761 if (ef->object == NULL) { 762 error = ENOMEM; 763 goto out; 764 } 765 ef->address = (caddr_t) vm_map_min(kernel_map); 766 767 /* 768 * In order to satisfy amd64's architectural requirements on the 769 * location of code and data in the kernel's address space, request a 770 * mapping that is above the kernel. 771 */ 772 #ifdef __amd64__ 773 mapbase = KERNBASE; 774 #else 775 mapbase = VM_MIN_KERNEL_ADDRESS; 776 #endif 777 error = vm_map_find(kernel_map, ef->object, 0, &mapbase, 778 round_page(mapsize), 0, VMFS_OPTIMAL_SPACE, VM_PROT_ALL, 779 VM_PROT_ALL, 0); 780 if (error) { 781 vm_object_deallocate(ef->object); 782 ef->object = 0; 783 goto out; 784 } 785 786 /* Wire the pages */ 787 error = vm_map_wire(kernel_map, mapbase, 788 mapbase + round_page(mapsize), 789 VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES); 790 if (error != KERN_SUCCESS) { 791 error = ENOMEM; 792 goto out; 793 } 794 795 /* Inform the kld system about the situation */ 796 lf->address = ef->address = (caddr_t)mapbase; 797 lf->size = mapsize; 798 799 /* 800 * Now load code/data(progbits), zero bss(nobits), allocate space for 801 * and load relocs 802 */ 803 pb = 0; 804 rl = 0; 805 ra = 0; 806 alignmask = 0; 807 for (i = 0; i < hdr->e_shnum; i++) { 808 if (shdr[i].sh_size == 0) 809 continue; 810 switch (shdr[i].sh_type) { 811 case SHT_PROGBITS: 812 case SHT_NOBITS: 813 #ifdef __amd64__ 814 case SHT_X86_64_UNWIND: 815 #endif 816 if ((shdr[i].sh_flags & SHF_ALLOC) == 0) 817 break; 818 alignmask = shdr[i].sh_addralign - 1; 819 mapbase += alignmask; 820 mapbase &= ~alignmask; 821 if (ef->shstrtab != NULL && shdr[i].sh_name != 0) { 822 ef->progtab[pb].name = 823 ef->shstrtab + shdr[i].sh_name; 824 if (!strcmp(ef->progtab[pb].name, ".ctors")) { 825 lf->ctors_addr = (caddr_t)mapbase; 826 lf->ctors_size = shdr[i].sh_size; 827 } 828 } else if (shdr[i].sh_type == SHT_PROGBITS) 829 ef->progtab[pb].name = "<<PROGBITS>>"; 830 #ifdef __amd64__ 831 else if (shdr[i].sh_type == SHT_X86_64_UNWIND) 832 ef->progtab[pb].name = "<<UNWIND>>"; 833 #endif 834 else 835 ef->progtab[pb].name = "<<NOBITS>>"; 836 if (ef->progtab[pb].name != NULL && 837 !strcmp(ef->progtab[pb].name, DPCPU_SETNAME)) 838 ef->progtab[pb].addr = 839 dpcpu_alloc(shdr[i].sh_size); 840 #ifdef VIMAGE 841 else if (ef->progtab[pb].name != NULL && 842 !strcmp(ef->progtab[pb].name, VNET_SETNAME)) 843 ef->progtab[pb].addr = 844 vnet_data_alloc(shdr[i].sh_size); 845 #endif 846 else 847 ef->progtab[pb].addr = 848 (void *)(uintptr_t)mapbase; 849 if (ef->progtab[pb].addr == NULL) { 850 error = ENOSPC; 851 goto out; 852 } 853 ef->progtab[pb].size = shdr[i].sh_size; 854 ef->progtab[pb].sec = i; 855 if (shdr[i].sh_type == SHT_PROGBITS 856 #ifdef __amd64__ 857 || shdr[i].sh_type == SHT_X86_64_UNWIND 858 #endif 859 ) { 860 error = vn_rdwr(UIO_READ, nd.ni_vp, 861 ef->progtab[pb].addr, 862 shdr[i].sh_size, shdr[i].sh_offset, 863 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, 864 NOCRED, &resid, td); 865 if (error) 866 goto out; 867 if (resid != 0){ 868 error = EINVAL; 869 goto out; 870 } 871 /* Initialize the per-cpu or vnet area. */ 872 if (ef->progtab[pb].addr != (void *)mapbase && 873 !strcmp(ef->progtab[pb].name, DPCPU_SETNAME)) 874 dpcpu_copy(ef->progtab[pb].addr, 875 shdr[i].sh_size); 876 #ifdef VIMAGE 877 else if (ef->progtab[pb].addr != 878 (void *)mapbase && 879 !strcmp(ef->progtab[pb].name, VNET_SETNAME)) 880 vnet_data_copy(ef->progtab[pb].addr, 881 shdr[i].sh_size); 882 #endif 883 } else 884 bzero(ef->progtab[pb].addr, shdr[i].sh_size); 885 886 /* Update all symbol values with the offset. */ 887 for (j = 0; j < ef->ddbsymcnt; j++) { 888 es = &ef->ddbsymtab[j]; 889 if (es->st_shndx != i) 890 continue; 891 es->st_value += (Elf_Addr)ef->progtab[pb].addr; 892 } 893 mapbase += shdr[i].sh_size; 894 pb++; 895 break; 896 case SHT_REL: 897 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0) 898 break; 899 ef->reltab[rl].rel = malloc(shdr[i].sh_size, M_LINKER, 900 M_WAITOK); 901 ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel); 902 ef->reltab[rl].sec = shdr[i].sh_info; 903 error = vn_rdwr(UIO_READ, nd.ni_vp, 904 (void *)ef->reltab[rl].rel, 905 shdr[i].sh_size, shdr[i].sh_offset, 906 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 907 &resid, td); 908 if (error) 909 goto out; 910 if (resid != 0){ 911 error = EINVAL; 912 goto out; 913 } 914 rl++; 915 break; 916 case SHT_RELA: 917 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0) 918 break; 919 ef->relatab[ra].rela = malloc(shdr[i].sh_size, M_LINKER, 920 M_WAITOK); 921 ef->relatab[ra].nrela = 922 shdr[i].sh_size / sizeof(Elf_Rela); 923 ef->relatab[ra].sec = shdr[i].sh_info; 924 error = vn_rdwr(UIO_READ, nd.ni_vp, 925 (void *)ef->relatab[ra].rela, 926 shdr[i].sh_size, shdr[i].sh_offset, 927 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 928 &resid, td); 929 if (error) 930 goto out; 931 if (resid != 0){ 932 error = EINVAL; 933 goto out; 934 } 935 ra++; 936 break; 937 } 938 } 939 if (pb != ef->nprogtab) { 940 link_elf_error(filename, "lost progbits"); 941 error = ENOEXEC; 942 goto out; 943 } 944 if (rl != ef->nreltab) { 945 link_elf_error(filename, "lost reltab"); 946 error = ENOEXEC; 947 goto out; 948 } 949 if (ra != ef->nrelatab) { 950 link_elf_error(filename, "lost relatab"); 951 error = ENOEXEC; 952 goto out; 953 } 954 if (mapbase != (vm_offset_t)ef->address + mapsize) { 955 printf( 956 "%s: mapbase 0x%lx != address %p + mapsize 0x%lx (0x%lx)\n", 957 filename != NULL ? filename : "<none>", 958 (u_long)mapbase, ef->address, (u_long)mapsize, 959 (u_long)(vm_offset_t)ef->address + mapsize); 960 error = ENOMEM; 961 goto out; 962 } 963 964 /* Local intra-module relocations */ 965 error = link_elf_reloc_local(lf); 966 if (error != 0) 967 goto out; 968 969 /* Pull in dependencies */ 970 VOP_UNLOCK(nd.ni_vp, 0); 971 error = linker_load_dependencies(lf); 972 vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY); 973 if (error) 974 goto out; 975 976 /* External relocations */ 977 error = relocate_file(ef); 978 if (error) 979 goto out; 980 981 /* Notify MD code that a module is being loaded. */ 982 error = elf_cpu_load_file(lf); 983 if (error) 984 goto out; 985 986 /* Invoke .ctors */ 987 link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size); 988 989 *result = lf; 990 991 out: 992 VOP_UNLOCK(nd.ni_vp, 0); 993 vn_close(nd.ni_vp, FREAD, td->td_ucred, td); 994 if (error && lf) 995 linker_file_unload(lf, LINKER_UNLOAD_FORCE); 996 free(hdr, M_LINKER); 997 998 return error; 999 } 1000 1001 static void 1002 link_elf_unload_file(linker_file_t file) 1003 { 1004 elf_file_t ef = (elf_file_t) file; 1005 int i; 1006 1007 /* Notify MD code that a module is being unloaded. */ 1008 elf_cpu_unload_file(file); 1009 1010 if (ef->progtab) { 1011 for (i = 0; i < ef->nprogtab; i++) { 1012 if (ef->progtab[i].size == 0) 1013 continue; 1014 if (ef->progtab[i].name == NULL) 1015 continue; 1016 if (!strcmp(ef->progtab[i].name, DPCPU_SETNAME)) 1017 dpcpu_free(ef->progtab[i].addr, 1018 ef->progtab[i].size); 1019 #ifdef VIMAGE 1020 else if (!strcmp(ef->progtab[i].name, VNET_SETNAME)) 1021 vnet_data_free(ef->progtab[i].addr, 1022 ef->progtab[i].size); 1023 #endif 1024 } 1025 } 1026 if (ef->preloaded) { 1027 free(ef->reltab, M_LINKER); 1028 free(ef->relatab, M_LINKER); 1029 free(ef->progtab, M_LINKER); 1030 free(ef->ctftab, M_LINKER); 1031 free(ef->ctfoff, M_LINKER); 1032 free(ef->typoff, M_LINKER); 1033 if (file->filename != NULL) 1034 preload_delete_name(file->filename); 1035 /* XXX reclaim module memory? */ 1036 return; 1037 } 1038 1039 for (i = 0; i < ef->nreltab; i++) 1040 free(ef->reltab[i].rel, M_LINKER); 1041 for (i = 0; i < ef->nrelatab; i++) 1042 free(ef->relatab[i].rela, M_LINKER); 1043 free(ef->reltab, M_LINKER); 1044 free(ef->relatab, M_LINKER); 1045 free(ef->progtab, M_LINKER); 1046 1047 if (ef->object) { 1048 vm_map_remove(kernel_map, (vm_offset_t) ef->address, 1049 (vm_offset_t) ef->address + 1050 (ef->object->size << PAGE_SHIFT)); 1051 } 1052 free(ef->e_shdr, M_LINKER); 1053 free(ef->ddbsymtab, M_LINKER); 1054 free(ef->ddbstrtab, M_LINKER); 1055 free(ef->shstrtab, M_LINKER); 1056 free(ef->ctftab, M_LINKER); 1057 free(ef->ctfoff, M_LINKER); 1058 free(ef->typoff, M_LINKER); 1059 } 1060 1061 static const char * 1062 symbol_name(elf_file_t ef, Elf_Size r_info) 1063 { 1064 const Elf_Sym *ref; 1065 1066 if (ELF_R_SYM(r_info)) { 1067 ref = ef->ddbsymtab + ELF_R_SYM(r_info); 1068 return ef->ddbstrtab + ref->st_name; 1069 } else 1070 return NULL; 1071 } 1072 1073 static Elf_Addr 1074 findbase(elf_file_t ef, int sec) 1075 { 1076 int i; 1077 Elf_Addr base = 0; 1078 1079 for (i = 0; i < ef->nprogtab; i++) { 1080 if (sec == ef->progtab[i].sec) { 1081 base = (Elf_Addr)ef->progtab[i].addr; 1082 break; 1083 } 1084 } 1085 return base; 1086 } 1087 1088 static int 1089 relocate_file(elf_file_t ef) 1090 { 1091 const Elf_Rel *rellim; 1092 const Elf_Rel *rel; 1093 const Elf_Rela *relalim; 1094 const Elf_Rela *rela; 1095 const char *symname; 1096 const Elf_Sym *sym; 1097 int i; 1098 Elf_Size symidx; 1099 Elf_Addr base; 1100 1101 1102 /* Perform relocations without addend if there are any: */ 1103 for (i = 0; i < ef->nreltab; i++) { 1104 rel = ef->reltab[i].rel; 1105 if (rel == NULL) { 1106 link_elf_error(ef->lf.filename, "lost a reltab!"); 1107 return (ENOEXEC); 1108 } 1109 rellim = rel + ef->reltab[i].nrel; 1110 base = findbase(ef, ef->reltab[i].sec); 1111 if (base == 0) { 1112 link_elf_error(ef->lf.filename, "lost base for reltab"); 1113 return (ENOEXEC); 1114 } 1115 for ( ; rel < rellim; rel++) { 1116 symidx = ELF_R_SYM(rel->r_info); 1117 if (symidx >= ef->ddbsymcnt) 1118 continue; 1119 sym = ef->ddbsymtab + symidx; 1120 /* Local relocs are already done */ 1121 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) 1122 continue; 1123 if (elf_reloc(&ef->lf, base, rel, ELF_RELOC_REL, 1124 elf_obj_lookup)) { 1125 symname = symbol_name(ef, rel->r_info); 1126 printf("link_elf_obj: symbol %s undefined\n", 1127 symname); 1128 return (ENOENT); 1129 } 1130 } 1131 } 1132 1133 /* Perform relocations with addend if there are any: */ 1134 for (i = 0; i < ef->nrelatab; i++) { 1135 rela = ef->relatab[i].rela; 1136 if (rela == NULL) { 1137 link_elf_error(ef->lf.filename, "lost a relatab!"); 1138 return (ENOEXEC); 1139 } 1140 relalim = rela + ef->relatab[i].nrela; 1141 base = findbase(ef, ef->relatab[i].sec); 1142 if (base == 0) { 1143 link_elf_error(ef->lf.filename, 1144 "lost base for relatab"); 1145 return (ENOEXEC); 1146 } 1147 for ( ; rela < relalim; rela++) { 1148 symidx = ELF_R_SYM(rela->r_info); 1149 if (symidx >= ef->ddbsymcnt) 1150 continue; 1151 sym = ef->ddbsymtab + symidx; 1152 /* Local relocs are already done */ 1153 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) 1154 continue; 1155 if (elf_reloc(&ef->lf, base, rela, ELF_RELOC_RELA, 1156 elf_obj_lookup)) { 1157 symname = symbol_name(ef, rela->r_info); 1158 printf("link_elf_obj: symbol %s undefined\n", 1159 symname); 1160 return (ENOENT); 1161 } 1162 } 1163 } 1164 1165 /* 1166 * Only clean SHN_FBSD_CACHED for successful return. If we 1167 * modified symbol table for the object but found an 1168 * unresolved symbol, there is no reason to roll back. 1169 */ 1170 elf_obj_cleanup_globals_cache(ef); 1171 1172 return (0); 1173 } 1174 1175 static int 1176 link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym) 1177 { 1178 elf_file_t ef = (elf_file_t) lf; 1179 const Elf_Sym *symp; 1180 const char *strp; 1181 int i; 1182 1183 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1184 strp = ef->ddbstrtab + symp->st_name; 1185 if (symp->st_shndx != SHN_UNDEF && strcmp(name, strp) == 0) { 1186 *sym = (c_linker_sym_t) symp; 1187 return 0; 1188 } 1189 } 1190 return ENOENT; 1191 } 1192 1193 static int 1194 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, 1195 linker_symval_t *symval) 1196 { 1197 elf_file_t ef; 1198 const Elf_Sym *es; 1199 caddr_t val; 1200 1201 ef = (elf_file_t) lf; 1202 es = (const Elf_Sym*) sym; 1203 val = (caddr_t)es->st_value; 1204 if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) { 1205 symval->name = ef->ddbstrtab + es->st_name; 1206 val = (caddr_t)es->st_value; 1207 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC) 1208 val = ((caddr_t (*)(void))val)(); 1209 symval->value = val; 1210 symval->size = es->st_size; 1211 return 0; 1212 } 1213 return ENOENT; 1214 } 1215 1216 static int 1217 link_elf_search_symbol(linker_file_t lf, caddr_t value, 1218 c_linker_sym_t *sym, long *diffp) 1219 { 1220 elf_file_t ef = (elf_file_t) lf; 1221 u_long off = (uintptr_t) (void *) value; 1222 u_long diff = off; 1223 u_long st_value; 1224 const Elf_Sym *es; 1225 const Elf_Sym *best = NULL; 1226 int i; 1227 1228 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) { 1229 if (es->st_name == 0) 1230 continue; 1231 st_value = es->st_value; 1232 if (off >= st_value) { 1233 if (off - st_value < diff) { 1234 diff = off - st_value; 1235 best = es; 1236 if (diff == 0) 1237 break; 1238 } else if (off - st_value == diff) { 1239 best = es; 1240 } 1241 } 1242 } 1243 if (best == NULL) 1244 *diffp = off; 1245 else 1246 *diffp = diff; 1247 *sym = (c_linker_sym_t) best; 1248 1249 return 0; 1250 } 1251 1252 /* 1253 * Look up a linker set on an ELF system. 1254 */ 1255 static int 1256 link_elf_lookup_set(linker_file_t lf, const char *name, 1257 void ***startp, void ***stopp, int *countp) 1258 { 1259 elf_file_t ef = (elf_file_t)lf; 1260 void **start, **stop; 1261 int i, count; 1262 1263 /* Relative to section number */ 1264 for (i = 0; i < ef->nprogtab; i++) { 1265 if ((strncmp(ef->progtab[i].name, "set_", 4) == 0) && 1266 strcmp(ef->progtab[i].name + 4, name) == 0) { 1267 start = (void **)ef->progtab[i].addr; 1268 stop = (void **)((char *)ef->progtab[i].addr + 1269 ef->progtab[i].size); 1270 count = stop - start; 1271 if (startp) 1272 *startp = start; 1273 if (stopp) 1274 *stopp = stop; 1275 if (countp) 1276 *countp = count; 1277 return (0); 1278 } 1279 } 1280 return (ESRCH); 1281 } 1282 1283 static int 1284 link_elf_each_function_name(linker_file_t file, 1285 int (*callback)(const char *, void *), void *opaque) 1286 { 1287 elf_file_t ef = (elf_file_t)file; 1288 const Elf_Sym *symp; 1289 int i, error; 1290 1291 /* Exhaustive search */ 1292 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1293 if (symp->st_value != 0 && 1294 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1295 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) { 1296 error = callback(ef->ddbstrtab + symp->st_name, opaque); 1297 if (error) 1298 return (error); 1299 } 1300 } 1301 return (0); 1302 } 1303 1304 static int 1305 link_elf_each_function_nameval(linker_file_t file, 1306 linker_function_nameval_callback_t callback, void *opaque) 1307 { 1308 linker_symval_t symval; 1309 elf_file_t ef = (elf_file_t)file; 1310 const Elf_Sym* symp; 1311 int i, error; 1312 1313 /* Exhaustive search */ 1314 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1315 if (symp->st_value != 0 && 1316 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1317 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) { 1318 error = link_elf_symbol_values(file, 1319 (c_linker_sym_t)symp, &symval); 1320 if (error) 1321 return (error); 1322 error = callback(file, i, &symval, opaque); 1323 if (error) 1324 return (error); 1325 } 1326 } 1327 return (0); 1328 } 1329 1330 static void 1331 elf_obj_cleanup_globals_cache(elf_file_t ef) 1332 { 1333 Elf_Sym *sym; 1334 Elf_Size i; 1335 1336 for (i = 0; i < ef->ddbsymcnt; i++) { 1337 sym = ef->ddbsymtab + i; 1338 if (sym->st_shndx == SHN_FBSD_CACHED) { 1339 sym->st_shndx = SHN_UNDEF; 1340 sym->st_value = 0; 1341 } 1342 } 1343 } 1344 1345 /* 1346 * Symbol lookup function that can be used when the symbol index is known (ie 1347 * in relocations). It uses the symbol index instead of doing a fully fledged 1348 * hash table based lookup when such is valid. For example for local symbols. 1349 * This is not only more efficient, it's also more correct. It's not always 1350 * the case that the symbol can be found through the hash table. 1351 */ 1352 static int 1353 elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res) 1354 { 1355 elf_file_t ef = (elf_file_t)lf; 1356 Elf_Sym *sym; 1357 const char *symbol; 1358 Elf_Addr res1; 1359 1360 /* Don't even try to lookup the symbol if the index is bogus. */ 1361 if (symidx >= ef->ddbsymcnt) { 1362 *res = 0; 1363 return (EINVAL); 1364 } 1365 1366 sym = ef->ddbsymtab + symidx; 1367 1368 /* Quick answer if there is a definition included. */ 1369 if (sym->st_shndx != SHN_UNDEF) { 1370 *res = sym->st_value; 1371 return (0); 1372 } 1373 1374 /* If we get here, then it is undefined and needs a lookup. */ 1375 switch (ELF_ST_BIND(sym->st_info)) { 1376 case STB_LOCAL: 1377 /* Local, but undefined? huh? */ 1378 *res = 0; 1379 return (EINVAL); 1380 1381 case STB_GLOBAL: 1382 case STB_WEAK: 1383 /* Relative to Data or Function name */ 1384 symbol = ef->ddbstrtab + sym->st_name; 1385 1386 /* Force a lookup failure if the symbol name is bogus. */ 1387 if (*symbol == 0) { 1388 *res = 0; 1389 return (EINVAL); 1390 } 1391 res1 = (Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps); 1392 1393 /* 1394 * Cache global lookups during module relocation. The failure 1395 * case is particularly expensive for callers, who must scan 1396 * through the entire globals table doing strcmp(). Cache to 1397 * avoid doing such work repeatedly. 1398 * 1399 * After relocation is complete, undefined globals will be 1400 * restored to SHN_UNDEF in elf_obj_cleanup_globals_cache(), 1401 * above. 1402 */ 1403 if (res1 != 0) { 1404 sym->st_shndx = SHN_FBSD_CACHED; 1405 sym->st_value = res1; 1406 *res = res1; 1407 return (0); 1408 } else if (ELF_ST_BIND(sym->st_info) == STB_WEAK) { 1409 sym->st_value = 0; 1410 *res = 0; 1411 return (0); 1412 } 1413 return (EINVAL); 1414 1415 default: 1416 return (EINVAL); 1417 } 1418 } 1419 1420 static void 1421 link_elf_fix_link_set(elf_file_t ef) 1422 { 1423 static const char startn[] = "__start_"; 1424 static const char stopn[] = "__stop_"; 1425 Elf_Sym *sym; 1426 const char *sym_name, *linkset_name; 1427 Elf_Addr startp, stopp; 1428 Elf_Size symidx; 1429 int start, i; 1430 1431 startp = stopp = 0; 1432 for (symidx = 1 /* zero entry is special */; 1433 symidx < ef->ddbsymcnt; symidx++) { 1434 sym = ef->ddbsymtab + symidx; 1435 if (sym->st_shndx != SHN_UNDEF) 1436 continue; 1437 1438 sym_name = ef->ddbstrtab + sym->st_name; 1439 if (strncmp(sym_name, startn, sizeof(startn) - 1) == 0) { 1440 start = 1; 1441 linkset_name = sym_name + sizeof(startn) - 1; 1442 } 1443 else if (strncmp(sym_name, stopn, sizeof(stopn) - 1) == 0) { 1444 start = 0; 1445 linkset_name = sym_name + sizeof(stopn) - 1; 1446 } 1447 else 1448 continue; 1449 1450 for (i = 0; i < ef->nprogtab; i++) { 1451 if (strcmp(ef->progtab[i].name, linkset_name) == 0) { 1452 startp = (Elf_Addr)ef->progtab[i].addr; 1453 stopp = (Elf_Addr)(startp + ef->progtab[i].size); 1454 break; 1455 } 1456 } 1457 if (i == ef->nprogtab) 1458 continue; 1459 1460 sym->st_value = start ? startp : stopp; 1461 sym->st_shndx = i; 1462 } 1463 } 1464 1465 static int 1466 link_elf_reloc_local(linker_file_t lf) 1467 { 1468 elf_file_t ef = (elf_file_t)lf; 1469 const Elf_Rel *rellim; 1470 const Elf_Rel *rel; 1471 const Elf_Rela *relalim; 1472 const Elf_Rela *rela; 1473 const Elf_Sym *sym; 1474 Elf_Addr base; 1475 int i; 1476 Elf_Size symidx; 1477 1478 link_elf_fix_link_set(ef); 1479 1480 /* Perform relocations without addend if there are any: */ 1481 for (i = 0; i < ef->nreltab; i++) { 1482 rel = ef->reltab[i].rel; 1483 if (rel == NULL) { 1484 link_elf_error(ef->lf.filename, "lost a reltab"); 1485 return (ENOEXEC); 1486 } 1487 rellim = rel + ef->reltab[i].nrel; 1488 base = findbase(ef, ef->reltab[i].sec); 1489 if (base == 0) { 1490 link_elf_error(ef->lf.filename, "lost base for reltab"); 1491 return (ENOEXEC); 1492 } 1493 for ( ; rel < rellim; rel++) { 1494 symidx = ELF_R_SYM(rel->r_info); 1495 if (symidx >= ef->ddbsymcnt) 1496 continue; 1497 sym = ef->ddbsymtab + symidx; 1498 /* Only do local relocs */ 1499 if (ELF_ST_BIND(sym->st_info) != STB_LOCAL) 1500 continue; 1501 elf_reloc_local(lf, base, rel, ELF_RELOC_REL, 1502 elf_obj_lookup); 1503 } 1504 } 1505 1506 /* Perform relocations with addend if there are any: */ 1507 for (i = 0; i < ef->nrelatab; i++) { 1508 rela = ef->relatab[i].rela; 1509 if (rela == NULL) { 1510 link_elf_error(ef->lf.filename, "lost a relatab!"); 1511 return (ENOEXEC); 1512 } 1513 relalim = rela + ef->relatab[i].nrela; 1514 base = findbase(ef, ef->relatab[i].sec); 1515 if (base == 0) { 1516 link_elf_error(ef->lf.filename, "lost base for reltab"); 1517 return (ENOEXEC); 1518 } 1519 for ( ; rela < relalim; rela++) { 1520 symidx = ELF_R_SYM(rela->r_info); 1521 if (symidx >= ef->ddbsymcnt) 1522 continue; 1523 sym = ef->ddbsymtab + symidx; 1524 /* Only do local relocs */ 1525 if (ELF_ST_BIND(sym->st_info) != STB_LOCAL) 1526 continue; 1527 elf_reloc_local(lf, base, rela, ELF_RELOC_RELA, 1528 elf_obj_lookup); 1529 } 1530 } 1531 return (0); 1532 } 1533 1534 static long 1535 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab) 1536 { 1537 elf_file_t ef = (elf_file_t)lf; 1538 1539 *symtab = ef->ddbsymtab; 1540 1541 if (*symtab == NULL) 1542 return (0); 1543 1544 return (ef->ddbsymcnt); 1545 } 1546 1547 static long 1548 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab) 1549 { 1550 elf_file_t ef = (elf_file_t)lf; 1551 1552 *strtab = ef->ddbstrtab; 1553 1554 if (*strtab == NULL) 1555 return (0); 1556 1557 return (ef->ddbstrcnt); 1558 }
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