link_elf_obj.c revision 338867
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: stable/11/sys/kern/link_elf_obj.c 338867 2018-09-21 20:40:37Z markj $"); 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 68typedef struct { 69 void *addr; 70 Elf_Off size; 71 int flags; 72 int sec; /* Original section */ 73 char *name; 74} Elf_progent; 75 76typedef struct { 77 Elf_Rel *rel; 78 int nrel; 79 int sec; 80} Elf_relent; 81 82typedef struct { 83 Elf_Rela *rela; 84 int nrela; 85 int sec; 86} Elf_relaent; 87 88 89typedef 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 124static int link_elf_link_preload(linker_class_t cls, 125 const char *, linker_file_t *); 126static int link_elf_link_preload_finish(linker_file_t); 127static int link_elf_load_file(linker_class_t, const char *, linker_file_t *); 128static int link_elf_lookup_symbol(linker_file_t, const char *, 129 c_linker_sym_t *); 130static int link_elf_symbol_values(linker_file_t, c_linker_sym_t, 131 linker_symval_t *); 132static int link_elf_search_symbol(linker_file_t, caddr_t value, 133 c_linker_sym_t *sym, long *diffp); 134 135static void link_elf_unload_file(linker_file_t); 136static int link_elf_lookup_set(linker_file_t, const char *, 137 void ***, void ***, int *); 138static int link_elf_each_function_name(linker_file_t, 139 int (*)(const char *, void *), void *); 140static int link_elf_each_function_nameval(linker_file_t, 141 linker_function_nameval_callback_t, 142 void *); 143static int link_elf_reloc_local(linker_file_t, bool); 144static long link_elf_symtab_get(linker_file_t, const Elf_Sym **); 145static long link_elf_strtab_get(linker_file_t, caddr_t *); 146 147static int elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps, 148 Elf_Addr *); 149 150static 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 167static 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 176static int relocate_file(elf_file_t ef); 177static void elf_obj_cleanup_globals_cache(elf_file_t); 178 179static void 180link_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 188static void 189link_elf_init(void *arg) 190{ 191 192 linker_add_class(&link_elf_class); 193} 194 195SYSINIT(link_elf_obj, SI_SUB_KLD, SI_ORDER_SECOND, link_elf_init, 0); 196 197static int 198link_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, false); 443 if (error != 0) 444 goto out; 445 *result = lf; 446 return (0); 447 448out: 449 /* preload not done this way */ 450 linker_file_unload(lf, LINKER_UNLOAD_FORCE); 451 return (error); 452} 453 454static void 455link_elf_invoke_ctors(caddr_t addr, size_t size) 456{ 457 void (**ctor)(void); 458 size_t i, cnt; 459 460 if (addr == NULL || size == 0) 461 return; 462 cnt = size / sizeof(*ctor); 463 ctor = (void *)addr; 464 for (i = 0; i < cnt; i++) { 465 if (ctor[i] != NULL) 466 (*ctor[i])(); 467 } 468} 469 470static int 471link_elf_link_preload_finish(linker_file_t lf) 472{ 473 elf_file_t ef; 474 int error; 475 476 ef = (elf_file_t)lf; 477 error = relocate_file(ef); 478 if (error) 479 return (error); 480 481 /* Notify MD code that a module is being loaded. */ 482 error = elf_cpu_load_file(lf); 483 if (error) 484 return (error); 485 486#if defined(__i386__) || defined(__amd64__) 487 /* Now ifuncs. */ 488 error = link_elf_reloc_local(lf, true); 489 if (error != 0) 490 return (error); 491#endif 492 493 /* Invoke .ctors */ 494 link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size); 495 return (0); 496} 497 498static int 499link_elf_load_file(linker_class_t cls, const char *filename, 500 linker_file_t *result) 501{ 502 struct nameidata nd; 503 struct thread *td = curthread; /* XXX */ 504 Elf_Ehdr *hdr; 505 Elf_Shdr *shdr; 506 Elf_Sym *es; 507 int nbytes, i, j; 508 vm_offset_t mapbase; 509 size_t mapsize; 510 int error = 0; 511 ssize_t resid; 512 int flags; 513 elf_file_t ef; 514 linker_file_t lf; 515 int symtabindex; 516 int symstrindex; 517 int shstrindex; 518 int nsym; 519 int pb, rl, ra; 520 int alignmask; 521 522 shdr = NULL; 523 lf = NULL; 524 mapsize = 0; 525 hdr = NULL; 526 527 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td); 528 flags = FREAD; 529 error = vn_open(&nd, &flags, 0, NULL); 530 if (error) 531 return error; 532 NDFREE(&nd, NDF_ONLY_PNBUF); 533 if (nd.ni_vp->v_type != VREG) { 534 error = ENOEXEC; 535 goto out; 536 } 537#ifdef MAC 538 error = mac_kld_check_load(td->td_ucred, nd.ni_vp); 539 if (error) { 540 goto out; 541 } 542#endif 543 544 /* Read the elf header from the file. */ 545 hdr = malloc(sizeof(*hdr), M_LINKER, M_WAITOK); 546 error = vn_rdwr(UIO_READ, nd.ni_vp, (void *)hdr, sizeof(*hdr), 0, 547 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 548 &resid, td); 549 if (error) 550 goto out; 551 if (resid != 0){ 552 error = ENOEXEC; 553 goto out; 554 } 555 556 if (!IS_ELF(*hdr)) { 557 error = ENOEXEC; 558 goto out; 559 } 560 561 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS 562 || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) { 563 link_elf_error(filename, "Unsupported file layout"); 564 error = ENOEXEC; 565 goto out; 566 } 567 if (hdr->e_ident[EI_VERSION] != EV_CURRENT 568 || hdr->e_version != EV_CURRENT) { 569 link_elf_error(filename, "Unsupported file version"); 570 error = ENOEXEC; 571 goto out; 572 } 573 if (hdr->e_type != ET_REL) { 574 error = ENOSYS; 575 goto out; 576 } 577 if (hdr->e_machine != ELF_TARG_MACH) { 578 link_elf_error(filename, "Unsupported machine"); 579 error = ENOEXEC; 580 goto out; 581 } 582 583 lf = linker_make_file(filename, &link_elf_class); 584 if (!lf) { 585 error = ENOMEM; 586 goto out; 587 } 588 ef = (elf_file_t) lf; 589 ef->nprogtab = 0; 590 ef->e_shdr = 0; 591 ef->nreltab = 0; 592 ef->nrelatab = 0; 593 594 /* Allocate and read in the section header */ 595 nbytes = hdr->e_shnum * hdr->e_shentsize; 596 if (nbytes == 0 || hdr->e_shoff == 0 || 597 hdr->e_shentsize != sizeof(Elf_Shdr)) { 598 error = ENOEXEC; 599 goto out; 600 } 601 shdr = malloc(nbytes, M_LINKER, M_WAITOK); 602 ef->e_shdr = shdr; 603 error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)shdr, nbytes, hdr->e_shoff, 604 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, &resid, td); 605 if (error) 606 goto out; 607 if (resid) { 608 error = ENOEXEC; 609 goto out; 610 } 611 612 /* Scan the section header for information and table sizing. */ 613 nsym = 0; 614 symtabindex = -1; 615 symstrindex = -1; 616 for (i = 0; i < hdr->e_shnum; i++) { 617 if (shdr[i].sh_size == 0) 618 continue; 619 switch (shdr[i].sh_type) { 620 case SHT_PROGBITS: 621 case SHT_NOBITS: 622#ifdef __amd64__ 623 case SHT_X86_64_UNWIND: 624#endif 625 if ((shdr[i].sh_flags & SHF_ALLOC) == 0) 626 break; 627 ef->nprogtab++; 628 break; 629 case SHT_SYMTAB: 630 nsym++; 631 symtabindex = i; 632 symstrindex = shdr[i].sh_link; 633 break; 634 case SHT_REL: 635 /* 636 * Ignore relocation tables for unallocated 637 * sections. 638 */ 639 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0) 640 break; 641 ef->nreltab++; 642 break; 643 case SHT_RELA: 644 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0) 645 break; 646 ef->nrelatab++; 647 break; 648 case SHT_STRTAB: 649 break; 650 } 651 } 652 if (ef->nprogtab == 0) { 653 link_elf_error(filename, "file has no contents"); 654 error = ENOEXEC; 655 goto out; 656 } 657 if (nsym != 1) { 658 /* Only allow one symbol table for now */ 659 link_elf_error(filename, "file has no valid symbol table"); 660 error = ENOEXEC; 661 goto out; 662 } 663 if (symstrindex < 0 || symstrindex > hdr->e_shnum || 664 shdr[symstrindex].sh_type != SHT_STRTAB) { 665 link_elf_error(filename, "file has invalid symbol strings"); 666 error = ENOEXEC; 667 goto out; 668 } 669 670 /* Allocate space for tracking the load chunks */ 671 if (ef->nprogtab != 0) 672 ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab), 673 M_LINKER, M_WAITOK | M_ZERO); 674 if (ef->nreltab != 0) 675 ef->reltab = malloc(ef->nreltab * sizeof(*ef->reltab), 676 M_LINKER, M_WAITOK | M_ZERO); 677 if (ef->nrelatab != 0) 678 ef->relatab = malloc(ef->nrelatab * sizeof(*ef->relatab), 679 M_LINKER, M_WAITOK | M_ZERO); 680 681 if (symtabindex == -1) { 682 link_elf_error(filename, "lost symbol table index"); 683 error = ENOEXEC; 684 goto out; 685 } 686 /* Allocate space for and load the symbol table */ 687 ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym); 688 ef->ddbsymtab = malloc(shdr[symtabindex].sh_size, M_LINKER, M_WAITOK); 689 error = vn_rdwr(UIO_READ, nd.ni_vp, (void *)ef->ddbsymtab, 690 shdr[symtabindex].sh_size, shdr[symtabindex].sh_offset, 691 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 692 &resid, td); 693 if (error) 694 goto out; 695 if (resid != 0){ 696 error = EINVAL; 697 goto out; 698 } 699 700 if (symstrindex == -1) { 701 link_elf_error(filename, "lost symbol string index"); 702 error = ENOEXEC; 703 goto out; 704 } 705 /* Allocate space for and load the symbol strings */ 706 ef->ddbstrcnt = shdr[symstrindex].sh_size; 707 ef->ddbstrtab = malloc(shdr[symstrindex].sh_size, M_LINKER, M_WAITOK); 708 error = vn_rdwr(UIO_READ, nd.ni_vp, ef->ddbstrtab, 709 shdr[symstrindex].sh_size, shdr[symstrindex].sh_offset, 710 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 711 &resid, td); 712 if (error) 713 goto out; 714 if (resid != 0){ 715 error = EINVAL; 716 goto out; 717 } 718 719 /* Do we have a string table for the section names? */ 720 shstrindex = -1; 721 if (hdr->e_shstrndx != 0 && 722 shdr[hdr->e_shstrndx].sh_type == SHT_STRTAB) { 723 shstrindex = hdr->e_shstrndx; 724 ef->shstrcnt = shdr[shstrindex].sh_size; 725 ef->shstrtab = malloc(shdr[shstrindex].sh_size, M_LINKER, 726 M_WAITOK); 727 error = vn_rdwr(UIO_READ, nd.ni_vp, ef->shstrtab, 728 shdr[shstrindex].sh_size, shdr[shstrindex].sh_offset, 729 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 730 &resid, td); 731 if (error) 732 goto out; 733 if (resid != 0){ 734 error = EINVAL; 735 goto out; 736 } 737 } 738 739 /* Size up code/data(progbits) and bss(nobits). */ 740 alignmask = 0; 741 for (i = 0; i < hdr->e_shnum; i++) { 742 if (shdr[i].sh_size == 0) 743 continue; 744 switch (shdr[i].sh_type) { 745 case SHT_PROGBITS: 746 case SHT_NOBITS: 747#ifdef __amd64__ 748 case SHT_X86_64_UNWIND: 749#endif 750 if ((shdr[i].sh_flags & SHF_ALLOC) == 0) 751 break; 752 alignmask = shdr[i].sh_addralign - 1; 753 mapsize += alignmask; 754 mapsize &= ~alignmask; 755 mapsize += shdr[i].sh_size; 756 break; 757 } 758 } 759 760 /* 761 * We know how much space we need for the text/data/bss/etc. 762 * This stuff needs to be in a single chunk so that profiling etc 763 * can get the bounds and gdb can associate offsets with modules 764 */ 765 ef->object = vm_object_allocate(OBJT_DEFAULT, 766 round_page(mapsize) >> PAGE_SHIFT); 767 if (ef->object == NULL) { 768 error = ENOMEM; 769 goto out; 770 } 771 ef->address = (caddr_t) vm_map_min(kernel_map); 772 773 /* 774 * In order to satisfy amd64's architectural requirements on the 775 * location of code and data in the kernel's address space, request a 776 * mapping that is above the kernel. 777 */ 778#ifdef __amd64__ 779 mapbase = KERNBASE; 780#else 781 mapbase = VM_MIN_KERNEL_ADDRESS; 782#endif 783 error = vm_map_find(kernel_map, ef->object, 0, &mapbase, 784 round_page(mapsize), 0, VMFS_OPTIMAL_SPACE, VM_PROT_ALL, 785 VM_PROT_ALL, 0); 786 if (error) { 787 vm_object_deallocate(ef->object); 788 ef->object = 0; 789 goto out; 790 } 791 792 /* Wire the pages */ 793 error = vm_map_wire(kernel_map, mapbase, 794 mapbase + round_page(mapsize), 795 VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES); 796 if (error != KERN_SUCCESS) { 797 error = ENOMEM; 798 goto out; 799 } 800 801 /* Inform the kld system about the situation */ 802 lf->address = ef->address = (caddr_t)mapbase; 803 lf->size = mapsize; 804 805 /* 806 * Now load code/data(progbits), zero bss(nobits), allocate space for 807 * and load relocs 808 */ 809 pb = 0; 810 rl = 0; 811 ra = 0; 812 alignmask = 0; 813 for (i = 0; i < hdr->e_shnum; i++) { 814 if (shdr[i].sh_size == 0) 815 continue; 816 switch (shdr[i].sh_type) { 817 case SHT_PROGBITS: 818 case SHT_NOBITS: 819#ifdef __amd64__ 820 case SHT_X86_64_UNWIND: 821#endif 822 if ((shdr[i].sh_flags & SHF_ALLOC) == 0) 823 break; 824 alignmask = shdr[i].sh_addralign - 1; 825 mapbase += alignmask; 826 mapbase &= ~alignmask; 827 if (ef->shstrtab != NULL && shdr[i].sh_name != 0) { 828 ef->progtab[pb].name = 829 ef->shstrtab + shdr[i].sh_name; 830 if (!strcmp(ef->progtab[pb].name, ".ctors")) { 831 lf->ctors_addr = (caddr_t)mapbase; 832 lf->ctors_size = shdr[i].sh_size; 833 } 834 } else if (shdr[i].sh_type == SHT_PROGBITS) 835 ef->progtab[pb].name = "<<PROGBITS>>"; 836#ifdef __amd64__ 837 else if (shdr[i].sh_type == SHT_X86_64_UNWIND) 838 ef->progtab[pb].name = "<<UNWIND>>"; 839#endif 840 else 841 ef->progtab[pb].name = "<<NOBITS>>"; 842 if (ef->progtab[pb].name != NULL && 843 !strcmp(ef->progtab[pb].name, DPCPU_SETNAME)) 844 ef->progtab[pb].addr = 845 dpcpu_alloc(shdr[i].sh_size); 846#ifdef VIMAGE 847 else if (ef->progtab[pb].name != NULL && 848 !strcmp(ef->progtab[pb].name, VNET_SETNAME)) 849 ef->progtab[pb].addr = 850 vnet_data_alloc(shdr[i].sh_size); 851#endif 852 else 853 ef->progtab[pb].addr = 854 (void *)(uintptr_t)mapbase; 855 if (ef->progtab[pb].addr == NULL) { 856 error = ENOSPC; 857 goto out; 858 } 859 ef->progtab[pb].size = shdr[i].sh_size; 860 ef->progtab[pb].sec = i; 861 if (shdr[i].sh_type == SHT_PROGBITS 862#ifdef __amd64__ 863 || shdr[i].sh_type == SHT_X86_64_UNWIND 864#endif 865 ) { 866 error = vn_rdwr(UIO_READ, nd.ni_vp, 867 ef->progtab[pb].addr, 868 shdr[i].sh_size, shdr[i].sh_offset, 869 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, 870 NOCRED, &resid, td); 871 if (error) 872 goto out; 873 if (resid != 0){ 874 error = EINVAL; 875 goto out; 876 } 877 /* Initialize the per-cpu or vnet area. */ 878 if (ef->progtab[pb].addr != (void *)mapbase && 879 !strcmp(ef->progtab[pb].name, DPCPU_SETNAME)) 880 dpcpu_copy(ef->progtab[pb].addr, 881 shdr[i].sh_size); 882#ifdef VIMAGE 883 else if (ef->progtab[pb].addr != 884 (void *)mapbase && 885 !strcmp(ef->progtab[pb].name, VNET_SETNAME)) 886 vnet_data_copy(ef->progtab[pb].addr, 887 shdr[i].sh_size); 888#endif 889 } else 890 bzero(ef->progtab[pb].addr, shdr[i].sh_size); 891 892 /* Update all symbol values with the offset. */ 893 for (j = 0; j < ef->ddbsymcnt; j++) { 894 es = &ef->ddbsymtab[j]; 895 if (es->st_shndx != i) 896 continue; 897 es->st_value += (Elf_Addr)ef->progtab[pb].addr; 898 } 899 mapbase += shdr[i].sh_size; 900 pb++; 901 break; 902 case SHT_REL: 903 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0) 904 break; 905 ef->reltab[rl].rel = malloc(shdr[i].sh_size, M_LINKER, 906 M_WAITOK); 907 ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel); 908 ef->reltab[rl].sec = shdr[i].sh_info; 909 error = vn_rdwr(UIO_READ, nd.ni_vp, 910 (void *)ef->reltab[rl].rel, 911 shdr[i].sh_size, shdr[i].sh_offset, 912 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 913 &resid, td); 914 if (error) 915 goto out; 916 if (resid != 0){ 917 error = EINVAL; 918 goto out; 919 } 920 rl++; 921 break; 922 case SHT_RELA: 923 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0) 924 break; 925 ef->relatab[ra].rela = malloc(shdr[i].sh_size, M_LINKER, 926 M_WAITOK); 927 ef->relatab[ra].nrela = 928 shdr[i].sh_size / sizeof(Elf_Rela); 929 ef->relatab[ra].sec = shdr[i].sh_info; 930 error = vn_rdwr(UIO_READ, nd.ni_vp, 931 (void *)ef->relatab[ra].rela, 932 shdr[i].sh_size, shdr[i].sh_offset, 933 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 934 &resid, td); 935 if (error) 936 goto out; 937 if (resid != 0){ 938 error = EINVAL; 939 goto out; 940 } 941 ra++; 942 break; 943 } 944 } 945 if (pb != ef->nprogtab) { 946 link_elf_error(filename, "lost progbits"); 947 error = ENOEXEC; 948 goto out; 949 } 950 if (rl != ef->nreltab) { 951 link_elf_error(filename, "lost reltab"); 952 error = ENOEXEC; 953 goto out; 954 } 955 if (ra != ef->nrelatab) { 956 link_elf_error(filename, "lost relatab"); 957 error = ENOEXEC; 958 goto out; 959 } 960 if (mapbase != (vm_offset_t)ef->address + mapsize) { 961 printf( 962 "%s: mapbase 0x%lx != address %p + mapsize 0x%lx (0x%lx)\n", 963 filename != NULL ? filename : "<none>", 964 (u_long)mapbase, ef->address, (u_long)mapsize, 965 (u_long)(vm_offset_t)ef->address + mapsize); 966 error = ENOMEM; 967 goto out; 968 } 969 970 /* Local intra-module relocations */ 971 error = link_elf_reloc_local(lf, false); 972 if (error != 0) 973 goto out; 974 975 /* Pull in dependencies */ 976 VOP_UNLOCK(nd.ni_vp, 0); 977 error = linker_load_dependencies(lf); 978 vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY); 979 if (error) 980 goto out; 981 982 /* External relocations */ 983 error = relocate_file(ef); 984 if (error) 985 goto out; 986 987 /* Notify MD code that a module is being loaded. */ 988 error = elf_cpu_load_file(lf); 989 if (error) 990 goto out; 991 992#if defined(__i386__) || defined(__amd64__) 993 /* Now ifuncs. */ 994 error = link_elf_reloc_local(lf, true); 995 if (error != 0) 996 goto out; 997#endif 998 999 /* Invoke .ctors */ 1000 link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size); 1001 1002 *result = lf; 1003 1004out: 1005 VOP_UNLOCK(nd.ni_vp, 0); 1006 vn_close(nd.ni_vp, FREAD, td->td_ucred, td); 1007 if (error && lf) 1008 linker_file_unload(lf, LINKER_UNLOAD_FORCE); 1009 free(hdr, M_LINKER); 1010 1011 return error; 1012} 1013 1014static void 1015link_elf_unload_file(linker_file_t file) 1016{ 1017 elf_file_t ef = (elf_file_t) file; 1018 int i; 1019 1020 /* Notify MD code that a module is being unloaded. */ 1021 elf_cpu_unload_file(file); 1022 1023 if (ef->progtab) { 1024 for (i = 0; i < ef->nprogtab; i++) { 1025 if (ef->progtab[i].size == 0) 1026 continue; 1027 if (ef->progtab[i].name == NULL) 1028 continue; 1029 if (!strcmp(ef->progtab[i].name, DPCPU_SETNAME)) 1030 dpcpu_free(ef->progtab[i].addr, 1031 ef->progtab[i].size); 1032#ifdef VIMAGE 1033 else if (!strcmp(ef->progtab[i].name, VNET_SETNAME)) 1034 vnet_data_free(ef->progtab[i].addr, 1035 ef->progtab[i].size); 1036#endif 1037 } 1038 } 1039 if (ef->preloaded) { 1040 free(ef->reltab, M_LINKER); 1041 free(ef->relatab, M_LINKER); 1042 free(ef->progtab, M_LINKER); 1043 free(ef->ctftab, M_LINKER); 1044 free(ef->ctfoff, M_LINKER); 1045 free(ef->typoff, M_LINKER); 1046 if (file->pathname != NULL) 1047 preload_delete_name(file->pathname); 1048 return; 1049 } 1050 1051 for (i = 0; i < ef->nreltab; i++) 1052 free(ef->reltab[i].rel, M_LINKER); 1053 for (i = 0; i < ef->nrelatab; i++) 1054 free(ef->relatab[i].rela, M_LINKER); 1055 free(ef->reltab, M_LINKER); 1056 free(ef->relatab, M_LINKER); 1057 free(ef->progtab, M_LINKER); 1058 1059 if (ef->object) { 1060 vm_map_remove(kernel_map, (vm_offset_t) ef->address, 1061 (vm_offset_t) ef->address + 1062 (ef->object->size << PAGE_SHIFT)); 1063 } 1064 free(ef->e_shdr, M_LINKER); 1065 free(ef->ddbsymtab, M_LINKER); 1066 free(ef->ddbstrtab, M_LINKER); 1067 free(ef->shstrtab, M_LINKER); 1068 free(ef->ctftab, M_LINKER); 1069 free(ef->ctfoff, M_LINKER); 1070 free(ef->typoff, M_LINKER); 1071} 1072 1073static const char * 1074symbol_name(elf_file_t ef, Elf_Size r_info) 1075{ 1076 const Elf_Sym *ref; 1077 1078 if (ELF_R_SYM(r_info)) { 1079 ref = ef->ddbsymtab + ELF_R_SYM(r_info); 1080 return ef->ddbstrtab + ref->st_name; 1081 } else 1082 return NULL; 1083} 1084 1085static Elf_Addr 1086findbase(elf_file_t ef, int sec) 1087{ 1088 int i; 1089 Elf_Addr base = 0; 1090 1091 for (i = 0; i < ef->nprogtab; i++) { 1092 if (sec == ef->progtab[i].sec) { 1093 base = (Elf_Addr)ef->progtab[i].addr; 1094 break; 1095 } 1096 } 1097 return base; 1098} 1099 1100static int 1101relocate_file(elf_file_t ef) 1102{ 1103 const Elf_Rel *rellim; 1104 const Elf_Rel *rel; 1105 const Elf_Rela *relalim; 1106 const Elf_Rela *rela; 1107 const char *symname; 1108 const Elf_Sym *sym; 1109 int i; 1110 Elf_Size symidx; 1111 Elf_Addr base; 1112 1113 1114 /* Perform relocations without addend if there are any: */ 1115 for (i = 0; i < ef->nreltab; i++) { 1116 rel = ef->reltab[i].rel; 1117 if (rel == NULL) { 1118 link_elf_error(ef->lf.filename, "lost a reltab!"); 1119 return (ENOEXEC); 1120 } 1121 rellim = rel + ef->reltab[i].nrel; 1122 base = findbase(ef, ef->reltab[i].sec); 1123 if (base == 0) { 1124 link_elf_error(ef->lf.filename, "lost base for reltab"); 1125 return (ENOEXEC); 1126 } 1127 for ( ; rel < rellim; rel++) { 1128 symidx = ELF_R_SYM(rel->r_info); 1129 if (symidx >= ef->ddbsymcnt) 1130 continue; 1131 sym = ef->ddbsymtab + symidx; 1132 /* Local relocs are already done */ 1133 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) 1134 continue; 1135 if (elf_reloc(&ef->lf, base, rel, ELF_RELOC_REL, 1136 elf_obj_lookup)) { 1137 symname = symbol_name(ef, rel->r_info); 1138 printf("link_elf_obj: symbol %s undefined\n", 1139 symname); 1140 return (ENOENT); 1141 } 1142 } 1143 } 1144 1145 /* Perform relocations with addend if there are any: */ 1146 for (i = 0; i < ef->nrelatab; i++) { 1147 rela = ef->relatab[i].rela; 1148 if (rela == NULL) { 1149 link_elf_error(ef->lf.filename, "lost a relatab!"); 1150 return (ENOEXEC); 1151 } 1152 relalim = rela + ef->relatab[i].nrela; 1153 base = findbase(ef, ef->relatab[i].sec); 1154 if (base == 0) { 1155 link_elf_error(ef->lf.filename, 1156 "lost base for relatab"); 1157 return (ENOEXEC); 1158 } 1159 for ( ; rela < relalim; rela++) { 1160 symidx = ELF_R_SYM(rela->r_info); 1161 if (symidx >= ef->ddbsymcnt) 1162 continue; 1163 sym = ef->ddbsymtab + symidx; 1164 /* Local relocs are already done */ 1165 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) 1166 continue; 1167 if (elf_reloc(&ef->lf, base, rela, ELF_RELOC_RELA, 1168 elf_obj_lookup)) { 1169 symname = symbol_name(ef, rela->r_info); 1170 printf("link_elf_obj: symbol %s undefined\n", 1171 symname); 1172 return (ENOENT); 1173 } 1174 } 1175 } 1176 1177 /* 1178 * Only clean SHN_FBSD_CACHED for successful return. If we 1179 * modified symbol table for the object but found an 1180 * unresolved symbol, there is no reason to roll back. 1181 */ 1182 elf_obj_cleanup_globals_cache(ef); 1183 1184 return (0); 1185} 1186 1187static int 1188link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym) 1189{ 1190 elf_file_t ef = (elf_file_t) lf; 1191 const Elf_Sym *symp; 1192 const char *strp; 1193 int i; 1194 1195 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1196 strp = ef->ddbstrtab + symp->st_name; 1197 if (symp->st_shndx != SHN_UNDEF && strcmp(name, strp) == 0) { 1198 *sym = (c_linker_sym_t) symp; 1199 return 0; 1200 } 1201 } 1202 return ENOENT; 1203} 1204 1205static int 1206link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, 1207 linker_symval_t *symval) 1208{ 1209 elf_file_t ef; 1210 const Elf_Sym *es; 1211 caddr_t val; 1212 1213 ef = (elf_file_t) lf; 1214 es = (const Elf_Sym*) sym; 1215 val = (caddr_t)es->st_value; 1216 if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) { 1217 symval->name = ef->ddbstrtab + es->st_name; 1218 val = (caddr_t)es->st_value; 1219 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC) 1220 val = ((caddr_t (*)(void))val)(); 1221 symval->value = val; 1222 symval->size = es->st_size; 1223 return 0; 1224 } 1225 return ENOENT; 1226} 1227 1228static int 1229link_elf_search_symbol(linker_file_t lf, caddr_t value, 1230 c_linker_sym_t *sym, long *diffp) 1231{ 1232 elf_file_t ef = (elf_file_t) lf; 1233 u_long off = (uintptr_t) (void *) value; 1234 u_long diff = off; 1235 u_long st_value; 1236 const Elf_Sym *es; 1237 const Elf_Sym *best = NULL; 1238 int i; 1239 1240 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) { 1241 if (es->st_name == 0) 1242 continue; 1243 st_value = es->st_value; 1244 if (off >= st_value) { 1245 if (off - st_value < diff) { 1246 diff = off - st_value; 1247 best = es; 1248 if (diff == 0) 1249 break; 1250 } else if (off - st_value == diff) { 1251 best = es; 1252 } 1253 } 1254 } 1255 if (best == NULL) 1256 *diffp = off; 1257 else 1258 *diffp = diff; 1259 *sym = (c_linker_sym_t) best; 1260 1261 return 0; 1262} 1263 1264/* 1265 * Look up a linker set on an ELF system. 1266 */ 1267static int 1268link_elf_lookup_set(linker_file_t lf, const char *name, 1269 void ***startp, void ***stopp, int *countp) 1270{ 1271 elf_file_t ef = (elf_file_t)lf; 1272 void **start, **stop; 1273 int i, count; 1274 1275 /* Relative to section number */ 1276 for (i = 0; i < ef->nprogtab; i++) { 1277 if ((strncmp(ef->progtab[i].name, "set_", 4) == 0) && 1278 strcmp(ef->progtab[i].name + 4, name) == 0) { 1279 start = (void **)ef->progtab[i].addr; 1280 stop = (void **)((char *)ef->progtab[i].addr + 1281 ef->progtab[i].size); 1282 count = stop - start; 1283 if (startp) 1284 *startp = start; 1285 if (stopp) 1286 *stopp = stop; 1287 if (countp) 1288 *countp = count; 1289 return (0); 1290 } 1291 } 1292 return (ESRCH); 1293} 1294 1295static int 1296link_elf_each_function_name(linker_file_t file, 1297 int (*callback)(const char *, void *), void *opaque) 1298{ 1299 elf_file_t ef = (elf_file_t)file; 1300 const Elf_Sym *symp; 1301 int i, error; 1302 1303 /* Exhaustive search */ 1304 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1305 if (symp->st_value != 0 && 1306 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1307 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) { 1308 error = callback(ef->ddbstrtab + symp->st_name, opaque); 1309 if (error) 1310 return (error); 1311 } 1312 } 1313 return (0); 1314} 1315 1316static int 1317link_elf_each_function_nameval(linker_file_t file, 1318 linker_function_nameval_callback_t callback, void *opaque) 1319{ 1320 linker_symval_t symval; 1321 elf_file_t ef = (elf_file_t)file; 1322 const Elf_Sym* symp; 1323 int i, error; 1324 1325 /* Exhaustive search */ 1326 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1327 if (symp->st_value != 0 && 1328 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1329 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) { 1330 error = link_elf_symbol_values(file, 1331 (c_linker_sym_t)symp, &symval); 1332 if (error) 1333 return (error); 1334 error = callback(file, i, &symval, opaque); 1335 if (error) 1336 return (error); 1337 } 1338 } 1339 return (0); 1340} 1341 1342static void 1343elf_obj_cleanup_globals_cache(elf_file_t ef) 1344{ 1345 Elf_Sym *sym; 1346 Elf_Size i; 1347 1348 for (i = 0; i < ef->ddbsymcnt; i++) { 1349 sym = ef->ddbsymtab + i; 1350 if (sym->st_shndx == SHN_FBSD_CACHED) { 1351 sym->st_shndx = SHN_UNDEF; 1352 sym->st_value = 0; 1353 } 1354 } 1355} 1356 1357/* 1358 * Symbol lookup function that can be used when the symbol index is known (ie 1359 * in relocations). It uses the symbol index instead of doing a fully fledged 1360 * hash table based lookup when such is valid. For example for local symbols. 1361 * This is not only more efficient, it's also more correct. It's not always 1362 * the case that the symbol can be found through the hash table. 1363 */ 1364static int 1365elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res) 1366{ 1367 elf_file_t ef = (elf_file_t)lf; 1368 Elf_Sym *sym; 1369 const char *symbol; 1370 Elf_Addr res1; 1371 1372 /* Don't even try to lookup the symbol if the index is bogus. */ 1373 if (symidx >= ef->ddbsymcnt) { 1374 *res = 0; 1375 return (EINVAL); 1376 } 1377 1378 sym = ef->ddbsymtab + symidx; 1379 1380 /* Quick answer if there is a definition included. */ 1381 if (sym->st_shndx != SHN_UNDEF) { 1382 res1 = (Elf_Addr)sym->st_value; 1383 if (ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC) 1384 res1 = ((Elf_Addr (*)(void))res1)(); 1385 *res = res1; 1386 return (0); 1387 } 1388 1389 /* If we get here, then it is undefined and needs a lookup. */ 1390 switch (ELF_ST_BIND(sym->st_info)) { 1391 case STB_LOCAL: 1392 /* Local, but undefined? huh? */ 1393 *res = 0; 1394 return (EINVAL); 1395 1396 case STB_GLOBAL: 1397 case STB_WEAK: 1398 /* Relative to Data or Function name */ 1399 symbol = ef->ddbstrtab + sym->st_name; 1400 1401 /* Force a lookup failure if the symbol name is bogus. */ 1402 if (*symbol == 0) { 1403 *res = 0; 1404 return (EINVAL); 1405 } 1406 res1 = (Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps); 1407 1408 /* 1409 * Cache global lookups during module relocation. The failure 1410 * case is particularly expensive for callers, who must scan 1411 * through the entire globals table doing strcmp(). Cache to 1412 * avoid doing such work repeatedly. 1413 * 1414 * After relocation is complete, undefined globals will be 1415 * restored to SHN_UNDEF in elf_obj_cleanup_globals_cache(), 1416 * above. 1417 */ 1418 if (res1 != 0) { 1419 sym->st_shndx = SHN_FBSD_CACHED; 1420 sym->st_value = res1; 1421 *res = res1; 1422 return (0); 1423 } else if (ELF_ST_BIND(sym->st_info) == STB_WEAK) { 1424 sym->st_value = 0; 1425 *res = 0; 1426 return (0); 1427 } 1428 return (EINVAL); 1429 1430 default: 1431 return (EINVAL); 1432 } 1433} 1434 1435static void 1436link_elf_fix_link_set(elf_file_t ef) 1437{ 1438 static const char startn[] = "__start_"; 1439 static const char stopn[] = "__stop_"; 1440 Elf_Sym *sym; 1441 const char *sym_name, *linkset_name; 1442 Elf_Addr startp, stopp; 1443 Elf_Size symidx; 1444 int start, i; 1445 1446 startp = stopp = 0; 1447 for (symidx = 1 /* zero entry is special */; 1448 symidx < ef->ddbsymcnt; symidx++) { 1449 sym = ef->ddbsymtab + symidx; 1450 if (sym->st_shndx != SHN_UNDEF) 1451 continue; 1452 1453 sym_name = ef->ddbstrtab + sym->st_name; 1454 if (strncmp(sym_name, startn, sizeof(startn) - 1) == 0) { 1455 start = 1; 1456 linkset_name = sym_name + sizeof(startn) - 1; 1457 } 1458 else if (strncmp(sym_name, stopn, sizeof(stopn) - 1) == 0) { 1459 start = 0; 1460 linkset_name = sym_name + sizeof(stopn) - 1; 1461 } 1462 else 1463 continue; 1464 1465 for (i = 0; i < ef->nprogtab; i++) { 1466 if (strcmp(ef->progtab[i].name, linkset_name) == 0) { 1467 startp = (Elf_Addr)ef->progtab[i].addr; 1468 stopp = (Elf_Addr)(startp + ef->progtab[i].size); 1469 break; 1470 } 1471 } 1472 if (i == ef->nprogtab) 1473 continue; 1474 1475 sym->st_value = start ? startp : stopp; 1476 sym->st_shndx = i; 1477 } 1478} 1479 1480static int 1481link_elf_reloc_local(linker_file_t lf, bool ifuncs) 1482{ 1483 elf_file_t ef = (elf_file_t)lf; 1484 const Elf_Rel *rellim; 1485 const Elf_Rel *rel; 1486 const Elf_Rela *relalim; 1487 const Elf_Rela *rela; 1488 const Elf_Sym *sym; 1489 Elf_Addr base; 1490 int i; 1491 Elf_Size symidx; 1492 1493 link_elf_fix_link_set(ef); 1494 1495 /* Perform relocations without addend if there are any: */ 1496 for (i = 0; i < ef->nreltab; i++) { 1497 rel = ef->reltab[i].rel; 1498 if (rel == NULL) { 1499 link_elf_error(ef->lf.filename, "lost a reltab"); 1500 return (ENOEXEC); 1501 } 1502 rellim = rel + ef->reltab[i].nrel; 1503 base = findbase(ef, ef->reltab[i].sec); 1504 if (base == 0) { 1505 link_elf_error(ef->lf.filename, "lost base for reltab"); 1506 return (ENOEXEC); 1507 } 1508 for ( ; rel < rellim; rel++) { 1509 symidx = ELF_R_SYM(rel->r_info); 1510 if (symidx >= ef->ddbsymcnt) 1511 continue; 1512 sym = ef->ddbsymtab + symidx; 1513 /* Only do local relocs */ 1514 if (ELF_ST_BIND(sym->st_info) != STB_LOCAL) 1515 continue; 1516 if ((ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC || 1517 elf_is_ifunc_reloc(rel->r_info)) == ifuncs) 1518 elf_reloc_local(lf, base, rel, ELF_RELOC_REL, 1519 elf_obj_lookup); 1520 } 1521 } 1522 1523 /* Perform relocations with addend if there are any: */ 1524 for (i = 0; i < ef->nrelatab; i++) { 1525 rela = ef->relatab[i].rela; 1526 if (rela == NULL) { 1527 link_elf_error(ef->lf.filename, "lost a relatab!"); 1528 return (ENOEXEC); 1529 } 1530 relalim = rela + ef->relatab[i].nrela; 1531 base = findbase(ef, ef->relatab[i].sec); 1532 if (base == 0) { 1533 link_elf_error(ef->lf.filename, "lost base for reltab"); 1534 return (ENOEXEC); 1535 } 1536 for ( ; rela < relalim; rela++) { 1537 symidx = ELF_R_SYM(rela->r_info); 1538 if (symidx >= ef->ddbsymcnt) 1539 continue; 1540 sym = ef->ddbsymtab + symidx; 1541 /* Only do local relocs */ 1542 if (ELF_ST_BIND(sym->st_info) != STB_LOCAL) 1543 continue; 1544 if ((ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC || 1545 elf_is_ifunc_reloc(rela->r_info)) == ifuncs) 1546 elf_reloc_local(lf, base, rela, ELF_RELOC_RELA, 1547 elf_obj_lookup); 1548 } 1549 } 1550 return (0); 1551} 1552 1553static long 1554link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab) 1555{ 1556 elf_file_t ef = (elf_file_t)lf; 1557 1558 *symtab = ef->ddbsymtab; 1559 1560 if (*symtab == NULL) 1561 return (0); 1562 1563 return (ef->ddbsymcnt); 1564} 1565 1566static long 1567link_elf_strtab_get(linker_file_t lf, caddr_t *strtab) 1568{ 1569 elf_file_t ef = (elf_file_t)lf; 1570 1571 *strtab = ef->ddbstrtab; 1572 1573 if (*strtab == NULL) 1574 return (0); 1575 1576 return (ef->ddbstrcnt); 1577} 1578