1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 1998-2000 Doug Rabson 5 * Copyright (c) 2004 Peter Wemm 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 */ 29 30 #include <sys/cdefs.h> 31 __FBSDID("$FreeBSD$"); 32 33 #include "opt_ddb.h" 34 35 #include <sys/param.h> 36 #include <sys/systm.h> 37 #include <sys/kernel.h> 38 #include <sys/lock.h> 39 #include <sys/malloc.h> 40 #include <sys/mutex.h> 41 #include <sys/mount.h> 42 #include <sys/proc.h> 43 #include <sys/namei.h> 44 #include <sys/fcntl.h> 45 #include <sys/vnode.h> 46 #include <sys/linker.h> 47 48 #include <machine/elf.h> 49 50 #include <net/vnet.h> 51 52 #include <security/mac/mac_framework.h> 53 54 #include <vm/vm.h> 55 #include <vm/vm_param.h> 56 #include <vm/vm_object.h> 57 #include <vm/vm_kern.h> 58 #include <vm/vm_extern.h> 59 #include <vm/pmap.h> 60 #include <vm/vm_map.h> 61 62 #include <sys/link_elf.h> 63 64 #ifdef DDB_CTF 65 #include <sys/zlib.h> 66 #endif 67 68 #include "linker_if.h" 69 70 typedef struct { 71 void *addr; 72 Elf_Off size; 73 int flags; 74 int sec; /* Original section */ 75 char *name; 76 } Elf_progent; 77 78 typedef struct { 79 Elf_Rel *rel; 80 int nrel; 81 int sec; 82 } Elf_relent; 83 84 typedef struct { 85 Elf_Rela *rela; 86 int nrela; 87 int sec; 88 } Elf_relaent; 89 90 91 typedef struct elf_file { 92 struct linker_file lf; /* Common fields */ 93 94 int preloaded; 95 caddr_t address; /* Relocation address */ 96 vm_object_t object; /* VM object to hold file pages */ 97 Elf_Shdr *e_shdr; 98 99 Elf_progent *progtab; 100 u_int nprogtab; 101 102 Elf_relaent *relatab; 103 u_int nrelatab; 104 105 Elf_relent *reltab; 106 int nreltab; 107 108 Elf_Sym *ddbsymtab; /* The symbol table we are using */ 109 long ddbsymcnt; /* Number of symbols */ 110 caddr_t ddbstrtab; /* String table */ 111 long ddbstrcnt; /* number of bytes in string table */ 112 113 caddr_t shstrtab; /* Section name string table */ 114 long shstrcnt; /* number of bytes in string table */ 115 116 caddr_t ctftab; /* CTF table */ 117 long ctfcnt; /* number of bytes in CTF table */ 118 caddr_t ctfoff; /* CTF offset table */ 119 caddr_t typoff; /* Type offset table */ 120 long typlen; /* Number of type entries. */ 121 122 } *elf_file_t; 123 124 #include <kern/kern_ctf.c> 125 126 static int link_elf_link_preload(linker_class_t cls, 127 const char *, linker_file_t *); 128 static int link_elf_link_preload_finish(linker_file_t); 129 static int link_elf_load_file(linker_class_t, const char *, linker_file_t *); 130 static int link_elf_lookup_symbol(linker_file_t, const char *, 131 c_linker_sym_t *); 132 static int link_elf_symbol_values(linker_file_t, c_linker_sym_t, 133 linker_symval_t *); 134 static int link_elf_search_symbol(linker_file_t, caddr_t value, 135 c_linker_sym_t *sym, long *diffp); 136 137 static void link_elf_unload_file(linker_file_t); 138 static int link_elf_lookup_set(linker_file_t, const char *, 139 void ***, void ***, int *); 140 static int link_elf_each_function_name(linker_file_t, 141 int (*)(const char *, void *), void *); 142 static int link_elf_each_function_nameval(linker_file_t, 143 linker_function_nameval_callback_t, 144 void *); 145 static int link_elf_reloc_local(linker_file_t, bool); 146 static long link_elf_symtab_get(linker_file_t, const Elf_Sym **); 147 static long link_elf_strtab_get(linker_file_t, caddr_t *); 148 149 static int elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps, 150 Elf_Addr *); 151 152 static kobj_method_t link_elf_methods[] = { 153 KOBJMETHOD(linker_lookup_symbol, link_elf_lookup_symbol), 154 KOBJMETHOD(linker_symbol_values, link_elf_symbol_values), 155 KOBJMETHOD(linker_search_symbol, link_elf_search_symbol), 156 KOBJMETHOD(linker_unload, link_elf_unload_file), 157 KOBJMETHOD(linker_load_file, link_elf_load_file), 158 KOBJMETHOD(linker_link_preload, link_elf_link_preload), 159 KOBJMETHOD(linker_link_preload_finish, link_elf_link_preload_finish), 160 KOBJMETHOD(linker_lookup_set, link_elf_lookup_set), 161 KOBJMETHOD(linker_each_function_name, link_elf_each_function_name), 162 KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval), 163 KOBJMETHOD(linker_ctf_get, link_elf_ctf_get), 164 KOBJMETHOD(linker_symtab_get, link_elf_symtab_get), 165 KOBJMETHOD(linker_strtab_get, link_elf_strtab_get), 166 { 0, 0 } 167 }; 168 169 static struct linker_class link_elf_class = { 170 #if ELF_TARG_CLASS == ELFCLASS32 171 "elf32_obj", 172 #else 173 "elf64_obj", 174 #endif 175 link_elf_methods, sizeof(struct elf_file) 176 }; 177 178 static int relocate_file(elf_file_t ef); 179 static void elf_obj_cleanup_globals_cache(elf_file_t); 180 181 static void 182 link_elf_error(const char *filename, const char *s) 183 { 184 if (filename == NULL) 185 printf("kldload: %s\n", s); 186 else 187 printf("kldload: %s: %s\n", filename, s); 188 } 189 190 static void 191 link_elf_init(void *arg) 192 { 193 194 linker_add_class(&link_elf_class); 195 } 196 197 SYSINIT(link_elf_obj, SI_SUB_KLD, SI_ORDER_SECOND, link_elf_init, NULL); 198 199 static int 200 link_elf_link_preload(linker_class_t cls, const char *filename, 201 linker_file_t *result) 202 { 203 Elf_Ehdr *hdr; 204 Elf_Shdr *shdr; 205 Elf_Sym *es; 206 void *modptr, *baseptr, *sizeptr; 207 char *type; 208 elf_file_t ef; 209 linker_file_t lf; 210 Elf_Addr off; 211 int error, i, j, pb, ra, rl, shstrindex, symstrindex, symtabindex; 212 213 /* Look to see if we have the file preloaded */ 214 modptr = preload_search_by_name(filename); 215 if (modptr == NULL) 216 return ENOENT; 217 218 type = (char *)preload_search_info(modptr, MODINFO_TYPE); 219 baseptr = preload_search_info(modptr, MODINFO_ADDR); 220 sizeptr = preload_search_info(modptr, MODINFO_SIZE); 221 hdr = (Elf_Ehdr *)preload_search_info(modptr, MODINFO_METADATA | 222 MODINFOMD_ELFHDR); 223 shdr = (Elf_Shdr *)preload_search_info(modptr, MODINFO_METADATA | 224 MODINFOMD_SHDR); 225 if (type == NULL || (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) 226 " obj module") != 0 && 227 strcmp(type, "elf obj module") != 0)) { 228 return (EFTYPE); 229 } 230 if (baseptr == NULL || sizeptr == NULL || hdr == NULL || 231 shdr == NULL) 232 return (EINVAL); 233 234 lf = linker_make_file(filename, &link_elf_class); 235 if (lf == NULL) 236 return (ENOMEM); 237 238 ef = (elf_file_t)lf; 239 ef->preloaded = 1; 240 ef->address = *(caddr_t *)baseptr; 241 lf->address = *(caddr_t *)baseptr; 242 lf->size = *(size_t *)sizeptr; 243 244 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS || 245 hdr->e_ident[EI_DATA] != ELF_TARG_DATA || 246 hdr->e_ident[EI_VERSION] != EV_CURRENT || 247 hdr->e_version != EV_CURRENT || 248 hdr->e_type != ET_REL || 249 hdr->e_machine != ELF_TARG_MACH) { 250 error = EFTYPE; 251 goto out; 252 } 253 ef->e_shdr = shdr; 254 255 /* Scan the section header for information and table sizing. */ 256 symtabindex = -1; 257 symstrindex = -1; 258 for (i = 0; i < hdr->e_shnum; i++) { 259 switch (shdr[i].sh_type) { 260 case SHT_PROGBITS: 261 case SHT_NOBITS: 262 #ifdef __amd64__ 263 case SHT_X86_64_UNWIND: 264 #endif 265 /* Ignore sections not loaded by the loader. */ 266 if (shdr[i].sh_addr == 0) 267 break; 268 ef->nprogtab++; 269 break; 270 case SHT_SYMTAB: 271 symtabindex = i; 272 symstrindex = shdr[i].sh_link; 273 break; 274 case SHT_REL: 275 /* 276 * Ignore relocation tables for sections not 277 * loaded by the loader. 278 */ 279 if (shdr[shdr[i].sh_info].sh_addr == 0) 280 break; 281 ef->nreltab++; 282 break; 283 case SHT_RELA: 284 if (shdr[shdr[i].sh_info].sh_addr == 0) 285 break; 286 ef->nrelatab++; 287 break; 288 } 289 } 290 291 shstrindex = hdr->e_shstrndx; 292 if (ef->nprogtab == 0 || symstrindex < 0 || 293 symstrindex >= hdr->e_shnum || 294 shdr[symstrindex].sh_type != SHT_STRTAB || shstrindex == 0 || 295 shstrindex >= hdr->e_shnum || 296 shdr[shstrindex].sh_type != SHT_STRTAB) { 297 printf("%s: bad/missing section headers\n", filename); 298 error = ENOEXEC; 299 goto out; 300 } 301 302 /* Allocate space for tracking the load chunks */ 303 if (ef->nprogtab != 0) 304 ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab), 305 M_LINKER, M_WAITOK | M_ZERO); 306 if (ef->nreltab != 0) 307 ef->reltab = malloc(ef->nreltab * sizeof(*ef->reltab), 308 M_LINKER, M_WAITOK | M_ZERO); 309 if (ef->nrelatab != 0) 310 ef->relatab = malloc(ef->nrelatab * sizeof(*ef->relatab), 311 M_LINKER, M_WAITOK | M_ZERO); 312 if ((ef->nprogtab != 0 && ef->progtab == NULL) || 313 (ef->nreltab != 0 && ef->reltab == NULL) || 314 (ef->nrelatab != 0 && ef->relatab == NULL)) { 315 error = ENOMEM; 316 goto out; 317 } 318 319 /* XXX, relocate the sh_addr fields saved by the loader. */ 320 off = 0; 321 for (i = 0; i < hdr->e_shnum; i++) { 322 if (shdr[i].sh_addr != 0 && (off == 0 || shdr[i].sh_addr < off)) 323 off = shdr[i].sh_addr; 324 } 325 for (i = 0; i < hdr->e_shnum; i++) { 326 if (shdr[i].sh_addr != 0) 327 shdr[i].sh_addr = shdr[i].sh_addr - off + 328 (Elf_Addr)ef->address; 329 } 330 331 ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym); 332 ef->ddbsymtab = (Elf_Sym *)shdr[symtabindex].sh_addr; 333 ef->ddbstrcnt = shdr[symstrindex].sh_size; 334 ef->ddbstrtab = (char *)shdr[symstrindex].sh_addr; 335 ef->shstrcnt = shdr[shstrindex].sh_size; 336 ef->shstrtab = (char *)shdr[shstrindex].sh_addr; 337 338 /* Now fill out progtab and the relocation tables. */ 339 pb = 0; 340 rl = 0; 341 ra = 0; 342 for (i = 0; i < hdr->e_shnum; i++) { 343 switch (shdr[i].sh_type) { 344 case SHT_PROGBITS: 345 case SHT_NOBITS: 346 #ifdef __amd64__ 347 case SHT_X86_64_UNWIND: 348 #endif 349 if (shdr[i].sh_addr == 0) 350 break; 351 ef->progtab[pb].addr = (void *)shdr[i].sh_addr; 352 if (shdr[i].sh_type == SHT_PROGBITS) 353 ef->progtab[pb].name = "<<PROGBITS>>"; 354 #ifdef __amd64__ 355 else if (shdr[i].sh_type == SHT_X86_64_UNWIND) 356 ef->progtab[pb].name = "<<UNWIND>>"; 357 #endif 358 else 359 ef->progtab[pb].name = "<<NOBITS>>"; 360 ef->progtab[pb].size = shdr[i].sh_size; 361 ef->progtab[pb].sec = i; 362 if (ef->shstrtab && shdr[i].sh_name != 0) 363 ef->progtab[pb].name = 364 ef->shstrtab + shdr[i].sh_name; 365 if (ef->progtab[pb].name != NULL && 366 !strcmp(ef->progtab[pb].name, DPCPU_SETNAME)) { 367 void *dpcpu; 368 369 dpcpu = dpcpu_alloc(shdr[i].sh_size); 370 if (dpcpu == NULL) { 371 error = ENOSPC; 372 goto out; 373 } 374 memcpy(dpcpu, ef->progtab[pb].addr, 375 ef->progtab[pb].size); 376 dpcpu_copy(dpcpu, shdr[i].sh_size); 377 ef->progtab[pb].addr = dpcpu; 378 #ifdef VIMAGE 379 } else if (ef->progtab[pb].name != NULL && 380 !strcmp(ef->progtab[pb].name, VNET_SETNAME)) { 381 void *vnet_data; 382 383 vnet_data = vnet_data_alloc(shdr[i].sh_size); 384 if (vnet_data == NULL) { 385 error = ENOSPC; 386 goto out; 387 } 388 memcpy(vnet_data, ef->progtab[pb].addr, 389 ef->progtab[pb].size); 390 vnet_data_copy(vnet_data, shdr[i].sh_size); 391 ef->progtab[pb].addr = vnet_data; 392 #endif 393 } else if (ef->progtab[pb].name != NULL && 394 !strcmp(ef->progtab[pb].name, ".ctors")) { 395 lf->ctors_addr = ef->progtab[pb].addr; 396 lf->ctors_size = shdr[i].sh_size; 397 } 398 399 /* Update all symbol values with the offset. */ 400 for (j = 0; j < ef->ddbsymcnt; j++) { 401 es = &ef->ddbsymtab[j]; 402 if (es->st_shndx != i) 403 continue; 404 es->st_value += (Elf_Addr)ef->progtab[pb].addr; 405 } 406 pb++; 407 break; 408 case SHT_REL: 409 if (shdr[shdr[i].sh_info].sh_addr == 0) 410 break; 411 ef->reltab[rl].rel = (Elf_Rel *)shdr[i].sh_addr; 412 ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel); 413 ef->reltab[rl].sec = shdr[i].sh_info; 414 rl++; 415 break; 416 case SHT_RELA: 417 if (shdr[shdr[i].sh_info].sh_addr == 0) 418 break; 419 ef->relatab[ra].rela = (Elf_Rela *)shdr[i].sh_addr; 420 ef->relatab[ra].nrela = 421 shdr[i].sh_size / sizeof(Elf_Rela); 422 ef->relatab[ra].sec = shdr[i].sh_info; 423 ra++; 424 break; 425 } 426 } 427 if (pb != ef->nprogtab) { 428 printf("%s: lost progbits\n", filename); 429 error = ENOEXEC; 430 goto out; 431 } 432 if (rl != ef->nreltab) { 433 printf("%s: lost reltab\n", filename); 434 error = ENOEXEC; 435 goto out; 436 } 437 if (ra != ef->nrelatab) { 438 printf("%s: lost relatab\n", filename); 439 error = ENOEXEC; 440 goto out; 441 } 442 443 /* Local intra-module relocations */ 444 error = link_elf_reloc_local(lf, false); 445 if (error != 0) 446 goto out; 447 *result = lf; 448 return (0); 449 450 out: 451 /* preload not done this way */ 452 linker_file_unload(lf, LINKER_UNLOAD_FORCE); 453 return (error); 454 } 455 456 static void 457 link_elf_invoke_ctors(caddr_t addr, size_t size) 458 { 459 void (**ctor)(void); 460 size_t i, cnt; 461 462 if (addr == NULL || size == 0) 463 return; 464 cnt = size / sizeof(*ctor); 465 ctor = (void *)addr; 466 for (i = 0; i < cnt; i++) { 467 if (ctor[i] != NULL) 468 (*ctor[i])(); 469 } 470 } 471 472 static int 473 link_elf_link_preload_finish(linker_file_t lf) 474 { 475 elf_file_t ef; 476 int error; 477 478 ef = (elf_file_t)lf; 479 error = relocate_file(ef); 480 if (error) 481 return (error); 482 483 /* Notify MD code that a module is being loaded. */ 484 error = elf_cpu_load_file(lf); 485 if (error) 486 return (error); 487 488 #if defined(__i386__) || defined(__amd64__) 489 /* Now ifuncs. */ 490 error = link_elf_reloc_local(lf, true); 491 if (error != 0) 492 return (error); 493 #endif 494 495 /* Invoke .ctors */ 496 link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size); 497 return (0); 498 } 499 500 static int 501 link_elf_load_file(linker_class_t cls, const char *filename, 502 linker_file_t *result) 503 { 504 struct nameidata *nd; 505 struct thread *td = curthread; /* XXX */ 506 Elf_Ehdr *hdr; 507 Elf_Shdr *shdr; 508 Elf_Sym *es; 509 int nbytes, i, j; 510 vm_offset_t mapbase; 511 size_t mapsize; 512 int error = 0; 513 ssize_t resid; 514 int flags; 515 elf_file_t ef; 516 linker_file_t lf; 517 int symtabindex; 518 int symstrindex; 519 int shstrindex; 520 int nsym; 521 int pb, rl, ra; 522 int alignmask; 523 524 shdr = NULL; 525 lf = NULL; 526 mapsize = 0; 527 hdr = NULL; 528 529 nd = malloc(sizeof(struct nameidata), M_TEMP, M_WAITOK); 530 NDINIT(nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td); 531 flags = FREAD; 532 error = vn_open(nd, &flags, 0, NULL); 533 if (error) { 534 free(nd, M_TEMP); 535 return error; 536 } 537 NDFREE(nd, NDF_ONLY_PNBUF); 538 if (nd->ni_vp->v_type != VREG) { 539 error = ENOEXEC; 540 goto out; 541 } 542 #ifdef MAC 543 error = mac_kld_check_load(td->td_ucred, nd->ni_vp); 544 if (error) { 545 goto out; 546 } 547 #endif 548 549 /* Read the elf header from the file. */ 550 hdr = malloc(sizeof(*hdr), M_LINKER, M_WAITOK); 551 error = vn_rdwr(UIO_READ, nd->ni_vp, (void *)hdr, sizeof(*hdr), 0, 552 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 553 &resid, td); 554 if (error) 555 goto out; 556 if (resid != 0){ 557 error = ENOEXEC; 558 goto out; 559 } 560 561 if (!IS_ELF(*hdr)) { 562 error = ENOEXEC; 563 goto out; 564 } 565 566 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS 567 || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) { 568 link_elf_error(filename, "Unsupported file layout"); 569 error = ENOEXEC; 570 goto out; 571 } 572 if (hdr->e_ident[EI_VERSION] != EV_CURRENT 573 || hdr->e_version != EV_CURRENT) { 574 link_elf_error(filename, "Unsupported file version"); 575 error = ENOEXEC; 576 goto out; 577 } 578 if (hdr->e_type != ET_REL) { 579 error = ENOSYS; 580 goto out; 581 } 582 if (hdr->e_machine != ELF_TARG_MACH) { 583 link_elf_error(filename, "Unsupported machine"); 584 error = ENOEXEC; 585 goto out; 586 } 587 588 lf = linker_make_file(filename, &link_elf_class); 589 if (!lf) { 590 error = ENOMEM; 591 goto out; 592 } 593 ef = (elf_file_t) lf; 594 ef->nprogtab = 0; 595 ef->e_shdr = 0; 596 ef->nreltab = 0; 597 ef->nrelatab = 0; 598 599 /* Allocate and read in the section header */ 600 nbytes = hdr->e_shnum * hdr->e_shentsize; 601 if (nbytes == 0 || hdr->e_shoff == 0 || 602 hdr->e_shentsize != sizeof(Elf_Shdr)) { 603 error = ENOEXEC; 604 goto out; 605 } 606 shdr = malloc(nbytes, M_LINKER, M_WAITOK); 607 ef->e_shdr = shdr; 608 error = vn_rdwr(UIO_READ, nd->ni_vp, (caddr_t)shdr, nbytes, 609 hdr->e_shoff, UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, 610 NOCRED, &resid, td); 611 if (error) 612 goto out; 613 if (resid) { 614 error = ENOEXEC; 615 goto out; 616 } 617 618 /* Scan the section header for information and table sizing. */ 619 nsym = 0; 620 symtabindex = -1; 621 symstrindex = -1; 622 for (i = 0; i < hdr->e_shnum; i++) { 623 if (shdr[i].sh_size == 0) 624 continue; 625 switch (shdr[i].sh_type) { 626 case SHT_PROGBITS: 627 case SHT_NOBITS: 628 #ifdef __amd64__ 629 case SHT_X86_64_UNWIND: 630 #endif 631 if ((shdr[i].sh_flags & SHF_ALLOC) == 0) 632 break; 633 ef->nprogtab++; 634 break; 635 case SHT_SYMTAB: 636 nsym++; 637 symtabindex = i; 638 symstrindex = shdr[i].sh_link; 639 break; 640 case SHT_REL: 641 /* 642 * Ignore relocation tables for unallocated 643 * sections. 644 */ 645 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0) 646 break; 647 ef->nreltab++; 648 break; 649 case SHT_RELA: 650 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0) 651 break; 652 ef->nrelatab++; 653 break; 654 case SHT_STRTAB: 655 break; 656 } 657 } 658 if (ef->nprogtab == 0) { 659 link_elf_error(filename, "file has no contents"); 660 error = ENOEXEC; 661 goto out; 662 } 663 if (nsym != 1) { 664 /* Only allow one symbol table for now */ 665 link_elf_error(filename, 666 "file must have exactly one symbol table"); 667 error = ENOEXEC; 668 goto out; 669 } 670 if (symstrindex < 0 || symstrindex > hdr->e_shnum || 671 shdr[symstrindex].sh_type != SHT_STRTAB) { 672 link_elf_error(filename, "file has invalid symbol strings"); 673 error = ENOEXEC; 674 goto out; 675 } 676 677 /* Allocate space for tracking the load chunks */ 678 if (ef->nprogtab != 0) 679 ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab), 680 M_LINKER, M_WAITOK | M_ZERO); 681 if (ef->nreltab != 0) 682 ef->reltab = malloc(ef->nreltab * sizeof(*ef->reltab), 683 M_LINKER, M_WAITOK | M_ZERO); 684 if (ef->nrelatab != 0) 685 ef->relatab = malloc(ef->nrelatab * sizeof(*ef->relatab), 686 M_LINKER, M_WAITOK | M_ZERO); 687 688 if (symtabindex == -1) { 689 link_elf_error(filename, "lost symbol table index"); 690 error = ENOEXEC; 691 goto out; 692 } 693 /* Allocate space for and load the symbol table */ 694 ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym); 695 ef->ddbsymtab = malloc(shdr[symtabindex].sh_size, M_LINKER, M_WAITOK); 696 error = vn_rdwr(UIO_READ, nd->ni_vp, (void *)ef->ddbsymtab, 697 shdr[symtabindex].sh_size, shdr[symtabindex].sh_offset, 698 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 699 &resid, td); 700 if (error) 701 goto out; 702 if (resid != 0){ 703 error = EINVAL; 704 goto out; 705 } 706 707 if (symstrindex == -1) { 708 link_elf_error(filename, "lost symbol string index"); 709 error = ENOEXEC; 710 goto out; 711 } 712 /* Allocate space for and load the symbol strings */ 713 ef->ddbstrcnt = shdr[symstrindex].sh_size; 714 ef->ddbstrtab = malloc(shdr[symstrindex].sh_size, M_LINKER, M_WAITOK); 715 error = vn_rdwr(UIO_READ, nd->ni_vp, ef->ddbstrtab, 716 shdr[symstrindex].sh_size, shdr[symstrindex].sh_offset, 717 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 718 &resid, td); 719 if (error) 720 goto out; 721 if (resid != 0){ 722 error = EINVAL; 723 goto out; 724 } 725 726 /* Do we have a string table for the section names? */ 727 shstrindex = -1; 728 if (hdr->e_shstrndx != 0 && 729 shdr[hdr->e_shstrndx].sh_type == SHT_STRTAB) { 730 shstrindex = hdr->e_shstrndx; 731 ef->shstrcnt = shdr[shstrindex].sh_size; 732 ef->shstrtab = malloc(shdr[shstrindex].sh_size, M_LINKER, 733 M_WAITOK); 734 error = vn_rdwr(UIO_READ, nd->ni_vp, ef->shstrtab, 735 shdr[shstrindex].sh_size, shdr[shstrindex].sh_offset, 736 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 737 &resid, td); 738 if (error) 739 goto out; 740 if (resid != 0){ 741 error = EINVAL; 742 goto out; 743 } 744 } 745 746 /* Size up code/data(progbits) and bss(nobits). */ 747 alignmask = 0; 748 for (i = 0; i < hdr->e_shnum; i++) { 749 if (shdr[i].sh_size == 0) 750 continue; 751 switch (shdr[i].sh_type) { 752 case SHT_PROGBITS: 753 case SHT_NOBITS: 754 #ifdef __amd64__ 755 case SHT_X86_64_UNWIND: 756 #endif 757 if ((shdr[i].sh_flags & SHF_ALLOC) == 0) 758 break; 759 alignmask = shdr[i].sh_addralign - 1; 760 mapsize += alignmask; 761 mapsize &= ~alignmask; 762 mapsize += shdr[i].sh_size; 763 break; 764 } 765 } 766 767 /* 768 * We know how much space we need for the text/data/bss/etc. 769 * This stuff needs to be in a single chunk so that profiling etc 770 * can get the bounds and gdb can associate offsets with modules 771 */ 772 ef->object = vm_object_allocate(OBJT_DEFAULT, 773 round_page(mapsize) >> PAGE_SHIFT); 774 if (ef->object == NULL) { 775 error = ENOMEM; 776 goto out; 777 } 778 ef->address = (caddr_t) vm_map_min(kernel_map); 779 780 /* 781 * In order to satisfy amd64's architectural requirements on the 782 * location of code and data in the kernel's address space, request a 783 * mapping that is above the kernel. 784 */ 785 #ifdef __amd64__ 786 mapbase = KERNBASE; 787 #else 788 mapbase = VM_MIN_KERNEL_ADDRESS; 789 #endif 790 error = vm_map_find(kernel_map, ef->object, 0, &mapbase, 791 round_page(mapsize), 0, VMFS_OPTIMAL_SPACE, VM_PROT_ALL, 792 VM_PROT_ALL, 0); 793 if (error) { 794 vm_object_deallocate(ef->object); 795 ef->object = 0; 796 goto out; 797 } 798 799 /* Wire the pages */ 800 error = vm_map_wire(kernel_map, mapbase, 801 mapbase + round_page(mapsize), 802 VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES); 803 if (error != KERN_SUCCESS) { 804 error = ENOMEM; 805 goto out; 806 } 807 808 /* Inform the kld system about the situation */ 809 lf->address = ef->address = (caddr_t)mapbase; 810 lf->size = mapsize; 811 812 /* 813 * Now load code/data(progbits), zero bss(nobits), allocate space for 814 * and load relocs 815 */ 816 pb = 0; 817 rl = 0; 818 ra = 0; 819 alignmask = 0; 820 for (i = 0; i < hdr->e_shnum; i++) { 821 if (shdr[i].sh_size == 0) 822 continue; 823 switch (shdr[i].sh_type) { 824 case SHT_PROGBITS: 825 case SHT_NOBITS: 826 #ifdef __amd64__ 827 case SHT_X86_64_UNWIND: 828 #endif 829 if ((shdr[i].sh_flags & SHF_ALLOC) == 0) 830 break; 831 alignmask = shdr[i].sh_addralign - 1; 832 mapbase += alignmask; 833 mapbase &= ~alignmask; 834 if (ef->shstrtab != NULL && shdr[i].sh_name != 0) { 835 ef->progtab[pb].name = 836 ef->shstrtab + shdr[i].sh_name; 837 if (!strcmp(ef->progtab[pb].name, ".ctors")) { 838 lf->ctors_addr = (caddr_t)mapbase; 839 lf->ctors_size = shdr[i].sh_size; 840 } 841 } else if (shdr[i].sh_type == SHT_PROGBITS) 842 ef->progtab[pb].name = "<<PROGBITS>>"; 843 #ifdef __amd64__ 844 else if (shdr[i].sh_type == SHT_X86_64_UNWIND) 845 ef->progtab[pb].name = "<<UNWIND>>"; 846 #endif 847 else 848 ef->progtab[pb].name = "<<NOBITS>>"; 849 if (ef->progtab[pb].name != NULL && 850 !strcmp(ef->progtab[pb].name, DPCPU_SETNAME)) 851 ef->progtab[pb].addr = 852 dpcpu_alloc(shdr[i].sh_size); 853 #ifdef VIMAGE 854 else if (ef->progtab[pb].name != NULL && 855 !strcmp(ef->progtab[pb].name, VNET_SETNAME)) 856 ef->progtab[pb].addr = 857 vnet_data_alloc(shdr[i].sh_size); 858 #endif 859 else 860 ef->progtab[pb].addr = 861 (void *)(uintptr_t)mapbase; 862 if (ef->progtab[pb].addr == NULL) { 863 error = ENOSPC; 864 goto out; 865 } 866 ef->progtab[pb].size = shdr[i].sh_size; 867 ef->progtab[pb].sec = i; 868 if (shdr[i].sh_type == SHT_PROGBITS 869 #ifdef __amd64__ 870 || shdr[i].sh_type == SHT_X86_64_UNWIND 871 #endif 872 ) { 873 error = vn_rdwr(UIO_READ, nd->ni_vp, 874 ef->progtab[pb].addr, 875 shdr[i].sh_size, shdr[i].sh_offset, 876 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, 877 NOCRED, &resid, td); 878 if (error) 879 goto out; 880 if (resid != 0){ 881 error = EINVAL; 882 goto out; 883 } 884 /* Initialize the per-cpu or vnet area. */ 885 if (ef->progtab[pb].addr != (void *)mapbase && 886 !strcmp(ef->progtab[pb].name, DPCPU_SETNAME)) 887 dpcpu_copy(ef->progtab[pb].addr, 888 shdr[i].sh_size); 889 #ifdef VIMAGE 890 else if (ef->progtab[pb].addr != 891 (void *)mapbase && 892 !strcmp(ef->progtab[pb].name, VNET_SETNAME)) 893 vnet_data_copy(ef->progtab[pb].addr, 894 shdr[i].sh_size); 895 #endif 896 } else 897 bzero(ef->progtab[pb].addr, shdr[i].sh_size); 898 899 /* Update all symbol values with the offset. */ 900 for (j = 0; j < ef->ddbsymcnt; j++) { 901 es = &ef->ddbsymtab[j]; 902 if (es->st_shndx != i) 903 continue; 904 es->st_value += (Elf_Addr)ef->progtab[pb].addr; 905 } 906 mapbase += shdr[i].sh_size; 907 pb++; 908 break; 909 case SHT_REL: 910 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0) 911 break; 912 ef->reltab[rl].rel = malloc(shdr[i].sh_size, M_LINKER, 913 M_WAITOK); 914 ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel); 915 ef->reltab[rl].sec = shdr[i].sh_info; 916 error = vn_rdwr(UIO_READ, nd->ni_vp, 917 (void *)ef->reltab[rl].rel, 918 shdr[i].sh_size, shdr[i].sh_offset, 919 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 920 &resid, td); 921 if (error) 922 goto out; 923 if (resid != 0){ 924 error = EINVAL; 925 goto out; 926 } 927 rl++; 928 break; 929 case SHT_RELA: 930 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0) 931 break; 932 ef->relatab[ra].rela = malloc(shdr[i].sh_size, M_LINKER, 933 M_WAITOK); 934 ef->relatab[ra].nrela = 935 shdr[i].sh_size / sizeof(Elf_Rela); 936 ef->relatab[ra].sec = shdr[i].sh_info; 937 error = vn_rdwr(UIO_READ, nd->ni_vp, 938 (void *)ef->relatab[ra].rela, 939 shdr[i].sh_size, shdr[i].sh_offset, 940 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 941 &resid, td); 942 if (error) 943 goto out; 944 if (resid != 0){ 945 error = EINVAL; 946 goto out; 947 } 948 ra++; 949 break; 950 } 951 } 952 if (pb != ef->nprogtab) { 953 link_elf_error(filename, "lost progbits"); 954 error = ENOEXEC; 955 goto out; 956 } 957 if (rl != ef->nreltab) { 958 link_elf_error(filename, "lost reltab"); 959 error = ENOEXEC; 960 goto out; 961 } 962 if (ra != ef->nrelatab) { 963 link_elf_error(filename, "lost relatab"); 964 error = ENOEXEC; 965 goto out; 966 } 967 if (mapbase != (vm_offset_t)ef->address + mapsize) { 968 printf( 969 "%s: mapbase 0x%lx != address %p + mapsize 0x%lx (0x%lx)\n", 970 filename != NULL ? filename : "<none>", 971 (u_long)mapbase, ef->address, (u_long)mapsize, 972 (u_long)(vm_offset_t)ef->address + mapsize); 973 error = ENOMEM; 974 goto out; 975 } 976 977 /* Local intra-module relocations */ 978 error = link_elf_reloc_local(lf, false); 979 if (error != 0) 980 goto out; 981 982 /* Pull in dependencies */ 983 VOP_UNLOCK(nd->ni_vp, 0); 984 error = linker_load_dependencies(lf); 985 vn_lock(nd->ni_vp, LK_EXCLUSIVE | LK_RETRY); 986 if (error) 987 goto out; 988 989 /* External relocations */ 990 error = relocate_file(ef); 991 if (error) 992 goto out; 993 994 /* Notify MD code that a module is being loaded. */ 995 error = elf_cpu_load_file(lf); 996 if (error) 997 goto out; 998 999 #if defined(__i386__) || defined(__amd64__) 1000 /* Now ifuncs. */ 1001 error = link_elf_reloc_local(lf, true); 1002 if (error != 0) 1003 goto out; 1004 #endif 1005 1006 /* Invoke .ctors */ 1007 link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size); 1008 1009 *result = lf; 1010 1011 out: 1012 VOP_UNLOCK(nd->ni_vp, 0); 1013 vn_close(nd->ni_vp, FREAD, td->td_ucred, td); 1014 free(nd, M_TEMP); 1015 if (error && lf) 1016 linker_file_unload(lf, LINKER_UNLOAD_FORCE); 1017 free(hdr, M_LINKER); 1018 1019 return error; 1020 } 1021 1022 static void 1023 link_elf_unload_file(linker_file_t file) 1024 { 1025 elf_file_t ef = (elf_file_t) file; 1026 u_int i; 1027 1028 /* Notify MD code that a module is being unloaded. */ 1029 elf_cpu_unload_file(file); 1030 1031 if (ef->progtab) { 1032 for (i = 0; i < ef->nprogtab; i++) { 1033 if (ef->progtab[i].size == 0) 1034 continue; 1035 if (ef->progtab[i].name == NULL) 1036 continue; 1037 if (!strcmp(ef->progtab[i].name, DPCPU_SETNAME)) 1038 dpcpu_free(ef->progtab[i].addr, 1039 ef->progtab[i].size); 1040 #ifdef VIMAGE 1041 else if (!strcmp(ef->progtab[i].name, VNET_SETNAME)) 1042 vnet_data_free(ef->progtab[i].addr, 1043 ef->progtab[i].size); 1044 #endif 1045 } 1046 } 1047 if (ef->preloaded) { 1048 free(ef->reltab, M_LINKER); 1049 free(ef->relatab, M_LINKER); 1050 free(ef->progtab, M_LINKER); 1051 free(ef->ctftab, M_LINKER); 1052 free(ef->ctfoff, M_LINKER); 1053 free(ef->typoff, M_LINKER); 1054 if (file->pathname != NULL) 1055 preload_delete_name(file->pathname); 1056 return; 1057 } 1058 1059 for (i = 0; i < ef->nreltab; i++) 1060 free(ef->reltab[i].rel, M_LINKER); 1061 for (i = 0; i < ef->nrelatab; i++) 1062 free(ef->relatab[i].rela, M_LINKER); 1063 free(ef->reltab, M_LINKER); 1064 free(ef->relatab, M_LINKER); 1065 free(ef->progtab, M_LINKER); 1066 1067 if (ef->object) { 1068 vm_map_remove(kernel_map, (vm_offset_t) ef->address, 1069 (vm_offset_t) ef->address + 1070 (ef->object->size << PAGE_SHIFT)); 1071 } 1072 free(ef->e_shdr, M_LINKER); 1073 free(ef->ddbsymtab, M_LINKER); 1074 free(ef->ddbstrtab, M_LINKER); 1075 free(ef->shstrtab, M_LINKER); 1076 free(ef->ctftab, M_LINKER); 1077 free(ef->ctfoff, M_LINKER); 1078 free(ef->typoff, M_LINKER); 1079 } 1080 1081 static const char * 1082 symbol_name(elf_file_t ef, Elf_Size r_info) 1083 { 1084 const Elf_Sym *ref; 1085 1086 if (ELF_R_SYM(r_info)) { 1087 ref = ef->ddbsymtab + ELF_R_SYM(r_info); 1088 return ef->ddbstrtab + ref->st_name; 1089 } else 1090 return NULL; 1091 } 1092 1093 static Elf_Addr 1094 findbase(elf_file_t ef, int sec) 1095 { 1096 int i; 1097 Elf_Addr base = 0; 1098 1099 for (i = 0; i < ef->nprogtab; i++) { 1100 if (sec == ef->progtab[i].sec) { 1101 base = (Elf_Addr)ef->progtab[i].addr; 1102 break; 1103 } 1104 } 1105 return base; 1106 } 1107 1108 static int 1109 relocate_file(elf_file_t ef) 1110 { 1111 const Elf_Rel *rellim; 1112 const Elf_Rel *rel; 1113 const Elf_Rela *relalim; 1114 const Elf_Rela *rela; 1115 const char *symname; 1116 const Elf_Sym *sym; 1117 int i; 1118 Elf_Size symidx; 1119 Elf_Addr base; 1120 1121 1122 /* Perform relocations without addend if there are any: */ 1123 for (i = 0; i < ef->nreltab; i++) { 1124 rel = ef->reltab[i].rel; 1125 if (rel == NULL) { 1126 link_elf_error(ef->lf.filename, "lost a reltab!"); 1127 return (ENOEXEC); 1128 } 1129 rellim = rel + ef->reltab[i].nrel; 1130 base = findbase(ef, ef->reltab[i].sec); 1131 if (base == 0) { 1132 link_elf_error(ef->lf.filename, "lost base for reltab"); 1133 return (ENOEXEC); 1134 } 1135 for ( ; rel < rellim; rel++) { 1136 symidx = ELF_R_SYM(rel->r_info); 1137 if (symidx >= ef->ddbsymcnt) 1138 continue; 1139 sym = ef->ddbsymtab + symidx; 1140 /* Local relocs are already done */ 1141 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) 1142 continue; 1143 if (elf_reloc(&ef->lf, base, rel, ELF_RELOC_REL, 1144 elf_obj_lookup)) { 1145 symname = symbol_name(ef, rel->r_info); 1146 printf("link_elf_obj: symbol %s undefined\n", 1147 symname); 1148 return (ENOENT); 1149 } 1150 } 1151 } 1152 1153 /* Perform relocations with addend if there are any: */ 1154 for (i = 0; i < ef->nrelatab; i++) { 1155 rela = ef->relatab[i].rela; 1156 if (rela == NULL) { 1157 link_elf_error(ef->lf.filename, "lost a relatab!"); 1158 return (ENOEXEC); 1159 } 1160 relalim = rela + ef->relatab[i].nrela; 1161 base = findbase(ef, ef->relatab[i].sec); 1162 if (base == 0) { 1163 link_elf_error(ef->lf.filename, 1164 "lost base for relatab"); 1165 return (ENOEXEC); 1166 } 1167 for ( ; rela < relalim; rela++) { 1168 symidx = ELF_R_SYM(rela->r_info); 1169 if (symidx >= ef->ddbsymcnt) 1170 continue; 1171 sym = ef->ddbsymtab + symidx; 1172 /* Local relocs are already done */ 1173 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) 1174 continue; 1175 if (elf_reloc(&ef->lf, base, rela, ELF_RELOC_RELA, 1176 elf_obj_lookup)) { 1177 symname = symbol_name(ef, rela->r_info); 1178 printf("link_elf_obj: symbol %s undefined\n", 1179 symname); 1180 return (ENOENT); 1181 } 1182 } 1183 } 1184 1185 /* 1186 * Only clean SHN_FBSD_CACHED for successful return. If we 1187 * modified symbol table for the object but found an 1188 * unresolved symbol, there is no reason to roll back. 1189 */ 1190 elf_obj_cleanup_globals_cache(ef); 1191 1192 return (0); 1193 } 1194 1195 static int 1196 link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym) 1197 { 1198 elf_file_t ef = (elf_file_t) lf; 1199 const Elf_Sym *symp; 1200 const char *strp; 1201 int i; 1202 1203 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1204 strp = ef->ddbstrtab + symp->st_name; 1205 if (symp->st_shndx != SHN_UNDEF && strcmp(name, strp) == 0) { 1206 *sym = (c_linker_sym_t) symp; 1207 return 0; 1208 } 1209 } 1210 return ENOENT; 1211 } 1212 1213 static int 1214 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, 1215 linker_symval_t *symval) 1216 { 1217 elf_file_t ef; 1218 const Elf_Sym *es; 1219 caddr_t val; 1220 1221 ef = (elf_file_t) lf; 1222 es = (const Elf_Sym*) sym; 1223 val = (caddr_t)es->st_value; 1224 if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) { 1225 symval->name = ef->ddbstrtab + es->st_name; 1226 val = (caddr_t)es->st_value; 1227 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC) 1228 val = ((caddr_t (*)(void))val)(); 1229 symval->value = val; 1230 symval->size = es->st_size; 1231 return 0; 1232 } 1233 return ENOENT; 1234 } 1235 1236 static int 1237 link_elf_search_symbol(linker_file_t lf, caddr_t value, 1238 c_linker_sym_t *sym, long *diffp) 1239 { 1240 elf_file_t ef = (elf_file_t) lf; 1241 u_long off = (uintptr_t) (void *) value; 1242 u_long diff = off; 1243 u_long st_value; 1244 const Elf_Sym *es; 1245 const Elf_Sym *best = NULL; 1246 int i; 1247 1248 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) { 1249 if (es->st_name == 0) 1250 continue; 1251 st_value = es->st_value; 1252 if (off >= st_value) { 1253 if (off - st_value < diff) { 1254 diff = off - st_value; 1255 best = es; 1256 if (diff == 0) 1257 break; 1258 } else if (off - st_value == diff) { 1259 best = es; 1260 } 1261 } 1262 } 1263 if (best == NULL) 1264 *diffp = off; 1265 else 1266 *diffp = diff; 1267 *sym = (c_linker_sym_t) best; 1268 1269 return 0; 1270 } 1271 1272 /* 1273 * Look up a linker set on an ELF system. 1274 */ 1275 static int 1276 link_elf_lookup_set(linker_file_t lf, const char *name, 1277 void ***startp, void ***stopp, int *countp) 1278 { 1279 elf_file_t ef = (elf_file_t)lf; 1280 void **start, **stop; 1281 int i, count; 1282 1283 /* Relative to section number */ 1284 for (i = 0; i < ef->nprogtab; i++) { 1285 if ((strncmp(ef->progtab[i].name, "set_", 4) == 0) && 1286 strcmp(ef->progtab[i].name + 4, name) == 0) { 1287 start = (void **)ef->progtab[i].addr; 1288 stop = (void **)((char *)ef->progtab[i].addr + 1289 ef->progtab[i].size); 1290 count = stop - start; 1291 if (startp) 1292 *startp = start; 1293 if (stopp) 1294 *stopp = stop; 1295 if (countp) 1296 *countp = count; 1297 return (0); 1298 } 1299 } 1300 return (ESRCH); 1301 } 1302 1303 static int 1304 link_elf_each_function_name(linker_file_t file, 1305 int (*callback)(const char *, void *), void *opaque) 1306 { 1307 elf_file_t ef = (elf_file_t)file; 1308 const Elf_Sym *symp; 1309 int i, error; 1310 1311 /* Exhaustive search */ 1312 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1313 if (symp->st_value != 0 && 1314 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1315 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) { 1316 error = callback(ef->ddbstrtab + symp->st_name, opaque); 1317 if (error) 1318 return (error); 1319 } 1320 } 1321 return (0); 1322 } 1323 1324 static int 1325 link_elf_each_function_nameval(linker_file_t file, 1326 linker_function_nameval_callback_t callback, void *opaque) 1327 { 1328 linker_symval_t symval; 1329 elf_file_t ef = (elf_file_t)file; 1330 const Elf_Sym* symp; 1331 int i, error; 1332 1333 /* Exhaustive search */ 1334 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1335 if (symp->st_value != 0 && 1336 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1337 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) { 1338 error = link_elf_symbol_values(file, 1339 (c_linker_sym_t)symp, &symval); 1340 if (error) 1341 return (error); 1342 error = callback(file, i, &symval, opaque); 1343 if (error) 1344 return (error); 1345 } 1346 } 1347 return (0); 1348 } 1349 1350 static void 1351 elf_obj_cleanup_globals_cache(elf_file_t ef) 1352 { 1353 Elf_Sym *sym; 1354 Elf_Size i; 1355 1356 for (i = 0; i < ef->ddbsymcnt; i++) { 1357 sym = ef->ddbsymtab + i; 1358 if (sym->st_shndx == SHN_FBSD_CACHED) { 1359 sym->st_shndx = SHN_UNDEF; 1360 sym->st_value = 0; 1361 } 1362 } 1363 } 1364 1365 /* 1366 * Symbol lookup function that can be used when the symbol index is known (ie 1367 * in relocations). It uses the symbol index instead of doing a fully fledged 1368 * hash table based lookup when such is valid. For example for local symbols. 1369 * This is not only more efficient, it's also more correct. It's not always 1370 * the case that the symbol can be found through the hash table. 1371 */ 1372 static int 1373 elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res) 1374 { 1375 elf_file_t ef = (elf_file_t)lf; 1376 Elf_Sym *sym; 1377 const char *symbol; 1378 Elf_Addr res1; 1379 1380 /* Don't even try to lookup the symbol if the index is bogus. */ 1381 if (symidx >= ef->ddbsymcnt) { 1382 *res = 0; 1383 return (EINVAL); 1384 } 1385 1386 sym = ef->ddbsymtab + symidx; 1387 1388 /* Quick answer if there is a definition included. */ 1389 if (sym->st_shndx != SHN_UNDEF) { 1390 res1 = (Elf_Addr)sym->st_value; 1391 if (ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC) 1392 res1 = ((Elf_Addr (*)(void))res1)(); 1393 *res = res1; 1394 return (0); 1395 } 1396 1397 /* If we get here, then it is undefined and needs a lookup. */ 1398 switch (ELF_ST_BIND(sym->st_info)) { 1399 case STB_LOCAL: 1400 /* Local, but undefined? huh? */ 1401 *res = 0; 1402 return (EINVAL); 1403 1404 case STB_GLOBAL: 1405 case STB_WEAK: 1406 /* Relative to Data or Function name */ 1407 symbol = ef->ddbstrtab + sym->st_name; 1408 1409 /* Force a lookup failure if the symbol name is bogus. */ 1410 if (*symbol == 0) { 1411 *res = 0; 1412 return (EINVAL); 1413 } 1414 res1 = (Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps); 1415 1416 /* 1417 * Cache global lookups during module relocation. The failure 1418 * case is particularly expensive for callers, who must scan 1419 * through the entire globals table doing strcmp(). Cache to 1420 * avoid doing such work repeatedly. 1421 * 1422 * After relocation is complete, undefined globals will be 1423 * restored to SHN_UNDEF in elf_obj_cleanup_globals_cache(), 1424 * above. 1425 */ 1426 if (res1 != 0) { 1427 sym->st_shndx = SHN_FBSD_CACHED; 1428 sym->st_value = res1; 1429 *res = res1; 1430 return (0); 1431 } else if (ELF_ST_BIND(sym->st_info) == STB_WEAK) { 1432 sym->st_value = 0; 1433 *res = 0; 1434 return (0); 1435 } 1436 return (EINVAL); 1437 1438 default: 1439 return (EINVAL); 1440 } 1441 } 1442 1443 static void 1444 link_elf_fix_link_set(elf_file_t ef) 1445 { 1446 static const char startn[] = "__start_"; 1447 static const char stopn[] = "__stop_"; 1448 Elf_Sym *sym; 1449 const char *sym_name, *linkset_name; 1450 Elf_Addr startp, stopp; 1451 Elf_Size symidx; 1452 int start, i; 1453 1454 startp = stopp = 0; 1455 for (symidx = 1 /* zero entry is special */; 1456 symidx < ef->ddbsymcnt; symidx++) { 1457 sym = ef->ddbsymtab + symidx; 1458 if (sym->st_shndx != SHN_UNDEF) 1459 continue; 1460 1461 sym_name = ef->ddbstrtab + sym->st_name; 1462 if (strncmp(sym_name, startn, sizeof(startn) - 1) == 0) { 1463 start = 1; 1464 linkset_name = sym_name + sizeof(startn) - 1; 1465 } 1466 else if (strncmp(sym_name, stopn, sizeof(stopn) - 1) == 0) { 1467 start = 0; 1468 linkset_name = sym_name + sizeof(stopn) - 1; 1469 } 1470 else 1471 continue; 1472 1473 for (i = 0; i < ef->nprogtab; i++) { 1474 if (strcmp(ef->progtab[i].name, linkset_name) == 0) { 1475 startp = (Elf_Addr)ef->progtab[i].addr; 1476 stopp = (Elf_Addr)(startp + ef->progtab[i].size); 1477 break; 1478 } 1479 } 1480 if (i == ef->nprogtab) 1481 continue; 1482 1483 sym->st_value = start ? startp : stopp; 1484 sym->st_shndx = i; 1485 } 1486 } 1487 1488 static int 1489 link_elf_reloc_local(linker_file_t lf, bool ifuncs) 1490 { 1491 elf_file_t ef = (elf_file_t)lf; 1492 const Elf_Rel *rellim; 1493 const Elf_Rel *rel; 1494 const Elf_Rela *relalim; 1495 const Elf_Rela *rela; 1496 const Elf_Sym *sym; 1497 Elf_Addr base; 1498 int i; 1499 Elf_Size symidx; 1500 1501 link_elf_fix_link_set(ef); 1502 1503 /* Perform relocations without addend if there are any: */ 1504 for (i = 0; i < ef->nreltab; i++) { 1505 rel = ef->reltab[i].rel; 1506 if (rel == NULL) { 1507 link_elf_error(ef->lf.filename, "lost a reltab"); 1508 return (ENOEXEC); 1509 } 1510 rellim = rel + ef->reltab[i].nrel; 1511 base = findbase(ef, ef->reltab[i].sec); 1512 if (base == 0) { 1513 link_elf_error(ef->lf.filename, "lost base for reltab"); 1514 return (ENOEXEC); 1515 } 1516 for ( ; rel < rellim; rel++) { 1517 symidx = ELF_R_SYM(rel->r_info); 1518 if (symidx >= ef->ddbsymcnt) 1519 continue; 1520 sym = ef->ddbsymtab + symidx; 1521 /* Only do local relocs */ 1522 if (ELF_ST_BIND(sym->st_info) != STB_LOCAL) 1523 continue; 1524 if ((ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC || 1525 elf_is_ifunc_reloc(rel->r_info)) == ifuncs) 1526 elf_reloc_local(lf, base, rel, ELF_RELOC_REL, 1527 elf_obj_lookup); 1528 } 1529 } 1530 1531 /* Perform relocations with addend if there are any: */ 1532 for (i = 0; i < ef->nrelatab; i++) { 1533 rela = ef->relatab[i].rela; 1534 if (rela == NULL) { 1535 link_elf_error(ef->lf.filename, "lost a relatab!"); 1536 return (ENOEXEC); 1537 } 1538 relalim = rela + ef->relatab[i].nrela; 1539 base = findbase(ef, ef->relatab[i].sec); 1540 if (base == 0) { 1541 link_elf_error(ef->lf.filename, "lost base for reltab"); 1542 return (ENOEXEC); 1543 } 1544 for ( ; rela < relalim; rela++) { 1545 symidx = ELF_R_SYM(rela->r_info); 1546 if (symidx >= ef->ddbsymcnt) 1547 continue; 1548 sym = ef->ddbsymtab + symidx; 1549 /* Only do local relocs */ 1550 if (ELF_ST_BIND(sym->st_info) != STB_LOCAL) 1551 continue; 1552 if ((ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC || 1553 elf_is_ifunc_reloc(rela->r_info)) == ifuncs) 1554 elf_reloc_local(lf, base, rela, ELF_RELOC_RELA, 1555 elf_obj_lookup); 1556 } 1557 } 1558 return (0); 1559 } 1560 1561 static long 1562 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab) 1563 { 1564 elf_file_t ef = (elf_file_t)lf; 1565 1566 *symtab = ef->ddbsymtab; 1567 1568 if (*symtab == NULL) 1569 return (0); 1570 1571 return (ef->ddbsymcnt); 1572 } 1573 1574 static long 1575 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab) 1576 { 1577 elf_file_t ef = (elf_file_t)lf; 1578 1579 *strtab = ef->ddbstrtab; 1580 1581 if (*strtab == NULL) 1582 return (0); 1583 1584 return (ef->ddbstrcnt); 1585 } 1586