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 * 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: releng/12.0/sys/kern/link_elf_obj.c 339953 2018-10-31 14:03:48Z bz $"); 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 printf("%s: pcpu module space is out " 372 "of space; cannot allocate %#jx " 373 "for %s\n", __func__, 374 (uintmax_t)shdr[i].sh_size, 375 filename); 376 error = ENOSPC; 377 goto out; 378 } 379 memcpy(dpcpu, ef->progtab[pb].addr, 380 ef->progtab[pb].size); 381 dpcpu_copy(dpcpu, shdr[i].sh_size); 382 ef->progtab[pb].addr = dpcpu; 383 #ifdef VIMAGE 384 } else if (ef->progtab[pb].name != NULL && 385 !strcmp(ef->progtab[pb].name, VNET_SETNAME)) { 386 void *vnet_data; 387 388 vnet_data = vnet_data_alloc(shdr[i].sh_size); 389 if (vnet_data == NULL) { 390 printf("%s: vnet module space is out " 391 "of space; cannot allocate %#jx " 392 "for %s\n", __func__, 393 (uintmax_t)shdr[i].sh_size, 394 filename); 395 error = ENOSPC; 396 goto out; 397 } 398 memcpy(vnet_data, ef->progtab[pb].addr, 399 ef->progtab[pb].size); 400 vnet_data_copy(vnet_data, shdr[i].sh_size); 401 ef->progtab[pb].addr = vnet_data; 402 #endif 403 } else if (ef->progtab[pb].name != NULL && 404 !strcmp(ef->progtab[pb].name, ".ctors")) { 405 lf->ctors_addr = ef->progtab[pb].addr; 406 lf->ctors_size = shdr[i].sh_size; 407 } 408 409 /* Update all symbol values with the offset. */ 410 for (j = 0; j < ef->ddbsymcnt; j++) { 411 es = &ef->ddbsymtab[j]; 412 if (es->st_shndx != i) 413 continue; 414 es->st_value += (Elf_Addr)ef->progtab[pb].addr; 415 } 416 pb++; 417 break; 418 case SHT_REL: 419 if (shdr[shdr[i].sh_info].sh_addr == 0) 420 break; 421 ef->reltab[rl].rel = (Elf_Rel *)shdr[i].sh_addr; 422 ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel); 423 ef->reltab[rl].sec = shdr[i].sh_info; 424 rl++; 425 break; 426 case SHT_RELA: 427 if (shdr[shdr[i].sh_info].sh_addr == 0) 428 break; 429 ef->relatab[ra].rela = (Elf_Rela *)shdr[i].sh_addr; 430 ef->relatab[ra].nrela = 431 shdr[i].sh_size / sizeof(Elf_Rela); 432 ef->relatab[ra].sec = shdr[i].sh_info; 433 ra++; 434 break; 435 } 436 } 437 if (pb != ef->nprogtab) { 438 printf("%s: lost progbits\n", filename); 439 error = ENOEXEC; 440 goto out; 441 } 442 if (rl != ef->nreltab) { 443 printf("%s: lost reltab\n", filename); 444 error = ENOEXEC; 445 goto out; 446 } 447 if (ra != ef->nrelatab) { 448 printf("%s: lost relatab\n", filename); 449 error = ENOEXEC; 450 goto out; 451 } 452 453 /* Local intra-module relocations */ 454 error = link_elf_reloc_local(lf, false); 455 if (error != 0) 456 goto out; 457 *result = lf; 458 return (0); 459 460 out: 461 /* preload not done this way */ 462 linker_file_unload(lf, LINKER_UNLOAD_FORCE); 463 return (error); 464 } 465 466 static void 467 link_elf_invoke_ctors(caddr_t addr, size_t size) 468 { 469 void (**ctor)(void); 470 size_t i, cnt; 471 472 if (addr == NULL || size == 0) 473 return; 474 cnt = size / sizeof(*ctor); 475 ctor = (void *)addr; 476 for (i = 0; i < cnt; i++) { 477 if (ctor[i] != NULL) 478 (*ctor[i])(); 479 } 480 } 481 482 static int 483 link_elf_link_preload_finish(linker_file_t lf) 484 { 485 elf_file_t ef; 486 int error; 487 488 ef = (elf_file_t)lf; 489 error = relocate_file(ef); 490 if (error) 491 return (error); 492 493 /* Notify MD code that a module is being loaded. */ 494 error = elf_cpu_load_file(lf); 495 if (error) 496 return (error); 497 498 #if defined(__i386__) || defined(__amd64__) 499 /* Now ifuncs. */ 500 error = link_elf_reloc_local(lf, true); 501 if (error != 0) 502 return (error); 503 #endif 504 505 /* Invoke .ctors */ 506 link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size); 507 return (0); 508 } 509 510 static int 511 link_elf_load_file(linker_class_t cls, const char *filename, 512 linker_file_t *result) 513 { 514 struct nameidata *nd; 515 struct thread *td = curthread; /* XXX */ 516 Elf_Ehdr *hdr; 517 Elf_Shdr *shdr; 518 Elf_Sym *es; 519 int nbytes, i, j; 520 vm_offset_t mapbase; 521 size_t mapsize; 522 int error = 0; 523 ssize_t resid; 524 int flags; 525 elf_file_t ef; 526 linker_file_t lf; 527 int symtabindex; 528 int symstrindex; 529 int shstrindex; 530 int nsym; 531 int pb, rl, ra; 532 int alignmask; 533 534 shdr = NULL; 535 lf = NULL; 536 mapsize = 0; 537 hdr = NULL; 538 539 nd = malloc(sizeof(struct nameidata), M_TEMP, M_WAITOK); 540 NDINIT(nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td); 541 flags = FREAD; 542 error = vn_open(nd, &flags, 0, NULL); 543 if (error) { 544 free(nd, M_TEMP); 545 return error; 546 } 547 NDFREE(nd, NDF_ONLY_PNBUF); 548 if (nd->ni_vp->v_type != VREG) { 549 error = ENOEXEC; 550 goto out; 551 } 552 #ifdef MAC 553 error = mac_kld_check_load(td->td_ucred, nd->ni_vp); 554 if (error) { 555 goto out; 556 } 557 #endif 558 559 /* Read the elf header from the file. */ 560 hdr = malloc(sizeof(*hdr), M_LINKER, M_WAITOK); 561 error = vn_rdwr(UIO_READ, nd->ni_vp, (void *)hdr, sizeof(*hdr), 0, 562 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 563 &resid, td); 564 if (error) 565 goto out; 566 if (resid != 0){ 567 error = ENOEXEC; 568 goto out; 569 } 570 571 if (!IS_ELF(*hdr)) { 572 error = ENOEXEC; 573 goto out; 574 } 575 576 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS 577 || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) { 578 link_elf_error(filename, "Unsupported file layout"); 579 error = ENOEXEC; 580 goto out; 581 } 582 if (hdr->e_ident[EI_VERSION] != EV_CURRENT 583 || hdr->e_version != EV_CURRENT) { 584 link_elf_error(filename, "Unsupported file version"); 585 error = ENOEXEC; 586 goto out; 587 } 588 if (hdr->e_type != ET_REL) { 589 error = ENOSYS; 590 goto out; 591 } 592 if (hdr->e_machine != ELF_TARG_MACH) { 593 link_elf_error(filename, "Unsupported machine"); 594 error = ENOEXEC; 595 goto out; 596 } 597 598 lf = linker_make_file(filename, &link_elf_class); 599 if (!lf) { 600 error = ENOMEM; 601 goto out; 602 } 603 ef = (elf_file_t) lf; 604 ef->nprogtab = 0; 605 ef->e_shdr = 0; 606 ef->nreltab = 0; 607 ef->nrelatab = 0; 608 609 /* Allocate and read in the section header */ 610 nbytes = hdr->e_shnum * hdr->e_shentsize; 611 if (nbytes == 0 || hdr->e_shoff == 0 || 612 hdr->e_shentsize != sizeof(Elf_Shdr)) { 613 error = ENOEXEC; 614 goto out; 615 } 616 shdr = malloc(nbytes, M_LINKER, M_WAITOK); 617 ef->e_shdr = shdr; 618 error = vn_rdwr(UIO_READ, nd->ni_vp, (caddr_t)shdr, nbytes, 619 hdr->e_shoff, UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, 620 NOCRED, &resid, td); 621 if (error) 622 goto out; 623 if (resid) { 624 error = ENOEXEC; 625 goto out; 626 } 627 628 /* Scan the section header for information and table sizing. */ 629 nsym = 0; 630 symtabindex = -1; 631 symstrindex = -1; 632 for (i = 0; i < hdr->e_shnum; i++) { 633 if (shdr[i].sh_size == 0) 634 continue; 635 switch (shdr[i].sh_type) { 636 case SHT_PROGBITS: 637 case SHT_NOBITS: 638 #ifdef __amd64__ 639 case SHT_X86_64_UNWIND: 640 #endif 641 if ((shdr[i].sh_flags & SHF_ALLOC) == 0) 642 break; 643 ef->nprogtab++; 644 break; 645 case SHT_SYMTAB: 646 nsym++; 647 symtabindex = i; 648 symstrindex = shdr[i].sh_link; 649 break; 650 case SHT_REL: 651 /* 652 * Ignore relocation tables for unallocated 653 * sections. 654 */ 655 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0) 656 break; 657 ef->nreltab++; 658 break; 659 case SHT_RELA: 660 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0) 661 break; 662 ef->nrelatab++; 663 break; 664 case SHT_STRTAB: 665 break; 666 } 667 } 668 if (ef->nprogtab == 0) { 669 link_elf_error(filename, "file has no contents"); 670 error = ENOEXEC; 671 goto out; 672 } 673 if (nsym != 1) { 674 /* Only allow one symbol table for now */ 675 link_elf_error(filename, 676 "file must have exactly one symbol table"); 677 error = ENOEXEC; 678 goto out; 679 } 680 if (symstrindex < 0 || symstrindex > hdr->e_shnum || 681 shdr[symstrindex].sh_type != SHT_STRTAB) { 682 link_elf_error(filename, "file has invalid symbol strings"); 683 error = ENOEXEC; 684 goto out; 685 } 686 687 /* Allocate space for tracking the load chunks */ 688 if (ef->nprogtab != 0) 689 ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab), 690 M_LINKER, M_WAITOK | M_ZERO); 691 if (ef->nreltab != 0) 692 ef->reltab = malloc(ef->nreltab * sizeof(*ef->reltab), 693 M_LINKER, M_WAITOK | M_ZERO); 694 if (ef->nrelatab != 0) 695 ef->relatab = malloc(ef->nrelatab * sizeof(*ef->relatab), 696 M_LINKER, M_WAITOK | M_ZERO); 697 698 if (symtabindex == -1) { 699 link_elf_error(filename, "lost symbol table index"); 700 error = ENOEXEC; 701 goto out; 702 } 703 /* Allocate space for and load the symbol table */ 704 ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym); 705 ef->ddbsymtab = malloc(shdr[symtabindex].sh_size, M_LINKER, M_WAITOK); 706 error = vn_rdwr(UIO_READ, nd->ni_vp, (void *)ef->ddbsymtab, 707 shdr[symtabindex].sh_size, shdr[symtabindex].sh_offset, 708 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 709 &resid, td); 710 if (error) 711 goto out; 712 if (resid != 0){ 713 error = EINVAL; 714 goto out; 715 } 716 717 if (symstrindex == -1) { 718 link_elf_error(filename, "lost symbol string index"); 719 error = ENOEXEC; 720 goto out; 721 } 722 /* Allocate space for and load the symbol strings */ 723 ef->ddbstrcnt = shdr[symstrindex].sh_size; 724 ef->ddbstrtab = malloc(shdr[symstrindex].sh_size, M_LINKER, M_WAITOK); 725 error = vn_rdwr(UIO_READ, nd->ni_vp, ef->ddbstrtab, 726 shdr[symstrindex].sh_size, shdr[symstrindex].sh_offset, 727 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 728 &resid, td); 729 if (error) 730 goto out; 731 if (resid != 0){ 732 error = EINVAL; 733 goto out; 734 } 735 736 /* Do we have a string table for the section names? */ 737 shstrindex = -1; 738 if (hdr->e_shstrndx != 0 && 739 shdr[hdr->e_shstrndx].sh_type == SHT_STRTAB) { 740 shstrindex = hdr->e_shstrndx; 741 ef->shstrcnt = shdr[shstrindex].sh_size; 742 ef->shstrtab = malloc(shdr[shstrindex].sh_size, M_LINKER, 743 M_WAITOK); 744 error = vn_rdwr(UIO_READ, nd->ni_vp, ef->shstrtab, 745 shdr[shstrindex].sh_size, shdr[shstrindex].sh_offset, 746 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 747 &resid, td); 748 if (error) 749 goto out; 750 if (resid != 0){ 751 error = EINVAL; 752 goto out; 753 } 754 } 755 756 /* Size up code/data(progbits) and bss(nobits). */ 757 alignmask = 0; 758 for (i = 0; i < hdr->e_shnum; i++) { 759 if (shdr[i].sh_size == 0) 760 continue; 761 switch (shdr[i].sh_type) { 762 case SHT_PROGBITS: 763 case SHT_NOBITS: 764 #ifdef __amd64__ 765 case SHT_X86_64_UNWIND: 766 #endif 767 if ((shdr[i].sh_flags & SHF_ALLOC) == 0) 768 break; 769 alignmask = shdr[i].sh_addralign - 1; 770 mapsize += alignmask; 771 mapsize &= ~alignmask; 772 mapsize += shdr[i].sh_size; 773 break; 774 } 775 } 776 777 /* 778 * We know how much space we need for the text/data/bss/etc. 779 * This stuff needs to be in a single chunk so that profiling etc 780 * can get the bounds and gdb can associate offsets with modules 781 */ 782 ef->object = vm_object_allocate(OBJT_DEFAULT, 783 round_page(mapsize) >> PAGE_SHIFT); 784 if (ef->object == NULL) { 785 error = ENOMEM; 786 goto out; 787 } 788 ef->address = (caddr_t) vm_map_min(kernel_map); 789 790 /* 791 * In order to satisfy amd64's architectural requirements on the 792 * location of code and data in the kernel's address space, request a 793 * mapping that is above the kernel. 794 */ 795 #ifdef __amd64__ 796 mapbase = KERNBASE; 797 #else 798 mapbase = VM_MIN_KERNEL_ADDRESS; 799 #endif 800 error = vm_map_find(kernel_map, ef->object, 0, &mapbase, 801 round_page(mapsize), 0, VMFS_OPTIMAL_SPACE, VM_PROT_ALL, 802 VM_PROT_ALL, 0); 803 if (error) { 804 vm_object_deallocate(ef->object); 805 ef->object = 0; 806 goto out; 807 } 808 809 /* Wire the pages */ 810 error = vm_map_wire(kernel_map, mapbase, 811 mapbase + round_page(mapsize), 812 VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES); 813 if (error != KERN_SUCCESS) { 814 error = ENOMEM; 815 goto out; 816 } 817 818 /* Inform the kld system about the situation */ 819 lf->address = ef->address = (caddr_t)mapbase; 820 lf->size = mapsize; 821 822 /* 823 * Now load code/data(progbits), zero bss(nobits), allocate space for 824 * and load relocs 825 */ 826 pb = 0; 827 rl = 0; 828 ra = 0; 829 alignmask = 0; 830 for (i = 0; i < hdr->e_shnum; i++) { 831 if (shdr[i].sh_size == 0) 832 continue; 833 switch (shdr[i].sh_type) { 834 case SHT_PROGBITS: 835 case SHT_NOBITS: 836 #ifdef __amd64__ 837 case SHT_X86_64_UNWIND: 838 #endif 839 if ((shdr[i].sh_flags & SHF_ALLOC) == 0) 840 break; 841 alignmask = shdr[i].sh_addralign - 1; 842 mapbase += alignmask; 843 mapbase &= ~alignmask; 844 if (ef->shstrtab != NULL && shdr[i].sh_name != 0) { 845 ef->progtab[pb].name = 846 ef->shstrtab + shdr[i].sh_name; 847 if (!strcmp(ef->progtab[pb].name, ".ctors")) { 848 lf->ctors_addr = (caddr_t)mapbase; 849 lf->ctors_size = shdr[i].sh_size; 850 } 851 } else if (shdr[i].sh_type == SHT_PROGBITS) 852 ef->progtab[pb].name = "<<PROGBITS>>"; 853 #ifdef __amd64__ 854 else if (shdr[i].sh_type == SHT_X86_64_UNWIND) 855 ef->progtab[pb].name = "<<UNWIND>>"; 856 #endif 857 else 858 ef->progtab[pb].name = "<<NOBITS>>"; 859 if (ef->progtab[pb].name != NULL && 860 !strcmp(ef->progtab[pb].name, DPCPU_SETNAME)) { 861 ef->progtab[pb].addr = 862 dpcpu_alloc(shdr[i].sh_size); 863 if (ef->progtab[pb].addr == NULL) { 864 printf("%s: pcpu module space is out " 865 "of space; cannot allocate %#jx " 866 "for %s\n", __func__, 867 (uintmax_t)shdr[i].sh_size, 868 filename); 869 } 870 } 871 #ifdef VIMAGE 872 else if (ef->progtab[pb].name != NULL && 873 !strcmp(ef->progtab[pb].name, VNET_SETNAME)) { 874 ef->progtab[pb].addr = 875 vnet_data_alloc(shdr[i].sh_size); 876 if (ef->progtab[pb].addr == NULL) { 877 printf("%s: vnet module space is out " 878 "of space; cannot allocate %#jx " 879 "for %s\n", __func__, 880 (uintmax_t)shdr[i].sh_size, 881 filename); 882 } 883 } 884 #endif 885 else 886 ef->progtab[pb].addr = 887 (void *)(uintptr_t)mapbase; 888 if (ef->progtab[pb].addr == NULL) { 889 error = ENOSPC; 890 goto out; 891 } 892 ef->progtab[pb].size = shdr[i].sh_size; 893 ef->progtab[pb].sec = i; 894 if (shdr[i].sh_type == SHT_PROGBITS 895 #ifdef __amd64__ 896 || shdr[i].sh_type == SHT_X86_64_UNWIND 897 #endif 898 ) { 899 error = vn_rdwr(UIO_READ, nd->ni_vp, 900 ef->progtab[pb].addr, 901 shdr[i].sh_size, shdr[i].sh_offset, 902 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, 903 NOCRED, &resid, td); 904 if (error) 905 goto out; 906 if (resid != 0){ 907 error = EINVAL; 908 goto out; 909 } 910 /* Initialize the per-cpu or vnet area. */ 911 if (ef->progtab[pb].addr != (void *)mapbase && 912 !strcmp(ef->progtab[pb].name, DPCPU_SETNAME)) 913 dpcpu_copy(ef->progtab[pb].addr, 914 shdr[i].sh_size); 915 #ifdef VIMAGE 916 else if (ef->progtab[pb].addr != 917 (void *)mapbase && 918 !strcmp(ef->progtab[pb].name, VNET_SETNAME)) 919 vnet_data_copy(ef->progtab[pb].addr, 920 shdr[i].sh_size); 921 #endif 922 } else 923 bzero(ef->progtab[pb].addr, shdr[i].sh_size); 924 925 /* Update all symbol values with the offset. */ 926 for (j = 0; j < ef->ddbsymcnt; j++) { 927 es = &ef->ddbsymtab[j]; 928 if (es->st_shndx != i) 929 continue; 930 es->st_value += (Elf_Addr)ef->progtab[pb].addr; 931 } 932 mapbase += shdr[i].sh_size; 933 pb++; 934 break; 935 case SHT_REL: 936 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0) 937 break; 938 ef->reltab[rl].rel = malloc(shdr[i].sh_size, M_LINKER, 939 M_WAITOK); 940 ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel); 941 ef->reltab[rl].sec = shdr[i].sh_info; 942 error = vn_rdwr(UIO_READ, nd->ni_vp, 943 (void *)ef->reltab[rl].rel, 944 shdr[i].sh_size, shdr[i].sh_offset, 945 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 946 &resid, td); 947 if (error) 948 goto out; 949 if (resid != 0){ 950 error = EINVAL; 951 goto out; 952 } 953 rl++; 954 break; 955 case SHT_RELA: 956 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0) 957 break; 958 ef->relatab[ra].rela = malloc(shdr[i].sh_size, M_LINKER, 959 M_WAITOK); 960 ef->relatab[ra].nrela = 961 shdr[i].sh_size / sizeof(Elf_Rela); 962 ef->relatab[ra].sec = shdr[i].sh_info; 963 error = vn_rdwr(UIO_READ, nd->ni_vp, 964 (void *)ef->relatab[ra].rela, 965 shdr[i].sh_size, shdr[i].sh_offset, 966 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 967 &resid, td); 968 if (error) 969 goto out; 970 if (resid != 0){ 971 error = EINVAL; 972 goto out; 973 } 974 ra++; 975 break; 976 } 977 } 978 if (pb != ef->nprogtab) { 979 link_elf_error(filename, "lost progbits"); 980 error = ENOEXEC; 981 goto out; 982 } 983 if (rl != ef->nreltab) { 984 link_elf_error(filename, "lost reltab"); 985 error = ENOEXEC; 986 goto out; 987 } 988 if (ra != ef->nrelatab) { 989 link_elf_error(filename, "lost relatab"); 990 error = ENOEXEC; 991 goto out; 992 } 993 if (mapbase != (vm_offset_t)ef->address + mapsize) { 994 printf( 995 "%s: mapbase 0x%lx != address %p + mapsize 0x%lx (0x%lx)\n", 996 filename != NULL ? filename : "<none>", 997 (u_long)mapbase, ef->address, (u_long)mapsize, 998 (u_long)(vm_offset_t)ef->address + mapsize); 999 error = ENOMEM; 1000 goto out; 1001 } 1002 1003 /* Local intra-module relocations */ 1004 error = link_elf_reloc_local(lf, false); 1005 if (error != 0) 1006 goto out; 1007 1008 /* Pull in dependencies */ 1009 VOP_UNLOCK(nd->ni_vp, 0); 1010 error = linker_load_dependencies(lf); 1011 vn_lock(nd->ni_vp, LK_EXCLUSIVE | LK_RETRY); 1012 if (error) 1013 goto out; 1014 1015 /* External relocations */ 1016 error = relocate_file(ef); 1017 if (error) 1018 goto out; 1019 1020 /* Notify MD code that a module is being loaded. */ 1021 error = elf_cpu_load_file(lf); 1022 if (error) 1023 goto out; 1024 1025 #if defined(__i386__) || defined(__amd64__) 1026 /* Now ifuncs. */ 1027 error = link_elf_reloc_local(lf, true); 1028 if (error != 0) 1029 goto out; 1030 #endif 1031 1032 /* Invoke .ctors */ 1033 link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size); 1034 1035 *result = lf; 1036 1037 out: 1038 VOP_UNLOCK(nd->ni_vp, 0); 1039 vn_close(nd->ni_vp, FREAD, td->td_ucred, td); 1040 free(nd, M_TEMP); 1041 if (error && lf) 1042 linker_file_unload(lf, LINKER_UNLOAD_FORCE); 1043 free(hdr, M_LINKER); 1044 1045 return error; 1046 } 1047 1048 static void 1049 link_elf_unload_file(linker_file_t file) 1050 { 1051 elf_file_t ef = (elf_file_t) file; 1052 u_int i; 1053 1054 /* Notify MD code that a module is being unloaded. */ 1055 elf_cpu_unload_file(file); 1056 1057 if (ef->progtab) { 1058 for (i = 0; i < ef->nprogtab; i++) { 1059 if (ef->progtab[i].size == 0) 1060 continue; 1061 if (ef->progtab[i].name == NULL) 1062 continue; 1063 if (!strcmp(ef->progtab[i].name, DPCPU_SETNAME)) 1064 dpcpu_free(ef->progtab[i].addr, 1065 ef->progtab[i].size); 1066 #ifdef VIMAGE 1067 else if (!strcmp(ef->progtab[i].name, VNET_SETNAME)) 1068 vnet_data_free(ef->progtab[i].addr, 1069 ef->progtab[i].size); 1070 #endif 1071 } 1072 } 1073 if (ef->preloaded) { 1074 free(ef->reltab, M_LINKER); 1075 free(ef->relatab, M_LINKER); 1076 free(ef->progtab, M_LINKER); 1077 free(ef->ctftab, M_LINKER); 1078 free(ef->ctfoff, M_LINKER); 1079 free(ef->typoff, M_LINKER); 1080 if (file->pathname != NULL) 1081 preload_delete_name(file->pathname); 1082 return; 1083 } 1084 1085 for (i = 0; i < ef->nreltab; i++) 1086 free(ef->reltab[i].rel, M_LINKER); 1087 for (i = 0; i < ef->nrelatab; i++) 1088 free(ef->relatab[i].rela, M_LINKER); 1089 free(ef->reltab, M_LINKER); 1090 free(ef->relatab, M_LINKER); 1091 free(ef->progtab, M_LINKER); 1092 1093 if (ef->object) { 1094 vm_map_remove(kernel_map, (vm_offset_t) ef->address, 1095 (vm_offset_t) ef->address + 1096 (ef->object->size << PAGE_SHIFT)); 1097 } 1098 free(ef->e_shdr, M_LINKER); 1099 free(ef->ddbsymtab, M_LINKER); 1100 free(ef->ddbstrtab, M_LINKER); 1101 free(ef->shstrtab, M_LINKER); 1102 free(ef->ctftab, M_LINKER); 1103 free(ef->ctfoff, M_LINKER); 1104 free(ef->typoff, M_LINKER); 1105 } 1106 1107 static const char * 1108 symbol_name(elf_file_t ef, Elf_Size r_info) 1109 { 1110 const Elf_Sym *ref; 1111 1112 if (ELF_R_SYM(r_info)) { 1113 ref = ef->ddbsymtab + ELF_R_SYM(r_info); 1114 return ef->ddbstrtab + ref->st_name; 1115 } else 1116 return NULL; 1117 } 1118 1119 static Elf_Addr 1120 findbase(elf_file_t ef, int sec) 1121 { 1122 int i; 1123 Elf_Addr base = 0; 1124 1125 for (i = 0; i < ef->nprogtab; i++) { 1126 if (sec == ef->progtab[i].sec) { 1127 base = (Elf_Addr)ef->progtab[i].addr; 1128 break; 1129 } 1130 } 1131 return base; 1132 } 1133 1134 static int 1135 relocate_file(elf_file_t ef) 1136 { 1137 const Elf_Rel *rellim; 1138 const Elf_Rel *rel; 1139 const Elf_Rela *relalim; 1140 const Elf_Rela *rela; 1141 const char *symname; 1142 const Elf_Sym *sym; 1143 int i; 1144 Elf_Size symidx; 1145 Elf_Addr base; 1146 1147 1148 /* Perform relocations without addend if there are any: */ 1149 for (i = 0; i < ef->nreltab; i++) { 1150 rel = ef->reltab[i].rel; 1151 if (rel == NULL) { 1152 link_elf_error(ef->lf.filename, "lost a reltab!"); 1153 return (ENOEXEC); 1154 } 1155 rellim = rel + ef->reltab[i].nrel; 1156 base = findbase(ef, ef->reltab[i].sec); 1157 if (base == 0) { 1158 link_elf_error(ef->lf.filename, "lost base for reltab"); 1159 return (ENOEXEC); 1160 } 1161 for ( ; rel < rellim; rel++) { 1162 symidx = ELF_R_SYM(rel->r_info); 1163 if (symidx >= ef->ddbsymcnt) 1164 continue; 1165 sym = ef->ddbsymtab + symidx; 1166 /* Local relocs are already done */ 1167 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) 1168 continue; 1169 if (elf_reloc(&ef->lf, base, rel, ELF_RELOC_REL, 1170 elf_obj_lookup)) { 1171 symname = symbol_name(ef, rel->r_info); 1172 printf("link_elf_obj: symbol %s undefined\n", 1173 symname); 1174 return (ENOENT); 1175 } 1176 } 1177 } 1178 1179 /* Perform relocations with addend if there are any: */ 1180 for (i = 0; i < ef->nrelatab; i++) { 1181 rela = ef->relatab[i].rela; 1182 if (rela == NULL) { 1183 link_elf_error(ef->lf.filename, "lost a relatab!"); 1184 return (ENOEXEC); 1185 } 1186 relalim = rela + ef->relatab[i].nrela; 1187 base = findbase(ef, ef->relatab[i].sec); 1188 if (base == 0) { 1189 link_elf_error(ef->lf.filename, 1190 "lost base for relatab"); 1191 return (ENOEXEC); 1192 } 1193 for ( ; rela < relalim; rela++) { 1194 symidx = ELF_R_SYM(rela->r_info); 1195 if (symidx >= ef->ddbsymcnt) 1196 continue; 1197 sym = ef->ddbsymtab + symidx; 1198 /* Local relocs are already done */ 1199 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) 1200 continue; 1201 if (elf_reloc(&ef->lf, base, rela, ELF_RELOC_RELA, 1202 elf_obj_lookup)) { 1203 symname = symbol_name(ef, rela->r_info); 1204 printf("link_elf_obj: symbol %s undefined\n", 1205 symname); 1206 return (ENOENT); 1207 } 1208 } 1209 } 1210 1211 /* 1212 * Only clean SHN_FBSD_CACHED for successful return. If we 1213 * modified symbol table for the object but found an 1214 * unresolved symbol, there is no reason to roll back. 1215 */ 1216 elf_obj_cleanup_globals_cache(ef); 1217 1218 return (0); 1219 } 1220 1221 static int 1222 link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym) 1223 { 1224 elf_file_t ef = (elf_file_t) lf; 1225 const Elf_Sym *symp; 1226 const char *strp; 1227 int i; 1228 1229 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1230 strp = ef->ddbstrtab + symp->st_name; 1231 if (symp->st_shndx != SHN_UNDEF && strcmp(name, strp) == 0) { 1232 *sym = (c_linker_sym_t) symp; 1233 return 0; 1234 } 1235 } 1236 return ENOENT; 1237 } 1238 1239 static int 1240 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, 1241 linker_symval_t *symval) 1242 { 1243 elf_file_t ef; 1244 const Elf_Sym *es; 1245 caddr_t val; 1246 1247 ef = (elf_file_t) lf; 1248 es = (const Elf_Sym*) sym; 1249 val = (caddr_t)es->st_value; 1250 if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) { 1251 symval->name = ef->ddbstrtab + es->st_name; 1252 val = (caddr_t)es->st_value; 1253 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC) 1254 val = ((caddr_t (*)(void))val)(); 1255 symval->value = val; 1256 symval->size = es->st_size; 1257 return 0; 1258 } 1259 return ENOENT; 1260 } 1261 1262 static int 1263 link_elf_search_symbol(linker_file_t lf, caddr_t value, 1264 c_linker_sym_t *sym, long *diffp) 1265 { 1266 elf_file_t ef = (elf_file_t) lf; 1267 u_long off = (uintptr_t) (void *) value; 1268 u_long diff = off; 1269 u_long st_value; 1270 const Elf_Sym *es; 1271 const Elf_Sym *best = NULL; 1272 int i; 1273 1274 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) { 1275 if (es->st_name == 0) 1276 continue; 1277 st_value = es->st_value; 1278 if (off >= st_value) { 1279 if (off - st_value < diff) { 1280 diff = off - st_value; 1281 best = es; 1282 if (diff == 0) 1283 break; 1284 } else if (off - st_value == diff) { 1285 best = es; 1286 } 1287 } 1288 } 1289 if (best == NULL) 1290 *diffp = off; 1291 else 1292 *diffp = diff; 1293 *sym = (c_linker_sym_t) best; 1294 1295 return 0; 1296 } 1297 1298 /* 1299 * Look up a linker set on an ELF system. 1300 */ 1301 static int 1302 link_elf_lookup_set(linker_file_t lf, const char *name, 1303 void ***startp, void ***stopp, int *countp) 1304 { 1305 elf_file_t ef = (elf_file_t)lf; 1306 void **start, **stop; 1307 int i, count; 1308 1309 /* Relative to section number */ 1310 for (i = 0; i < ef->nprogtab; i++) { 1311 if ((strncmp(ef->progtab[i].name, "set_", 4) == 0) && 1312 strcmp(ef->progtab[i].name + 4, name) == 0) { 1313 start = (void **)ef->progtab[i].addr; 1314 stop = (void **)((char *)ef->progtab[i].addr + 1315 ef->progtab[i].size); 1316 count = stop - start; 1317 if (startp) 1318 *startp = start; 1319 if (stopp) 1320 *stopp = stop; 1321 if (countp) 1322 *countp = count; 1323 return (0); 1324 } 1325 } 1326 return (ESRCH); 1327 } 1328 1329 static int 1330 link_elf_each_function_name(linker_file_t file, 1331 int (*callback)(const char *, void *), void *opaque) 1332 { 1333 elf_file_t ef = (elf_file_t)file; 1334 const Elf_Sym *symp; 1335 int i, error; 1336 1337 /* Exhaustive search */ 1338 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1339 if (symp->st_value != 0 && 1340 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1341 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) { 1342 error = callback(ef->ddbstrtab + symp->st_name, opaque); 1343 if (error) 1344 return (error); 1345 } 1346 } 1347 return (0); 1348 } 1349 1350 static int 1351 link_elf_each_function_nameval(linker_file_t file, 1352 linker_function_nameval_callback_t callback, void *opaque) 1353 { 1354 linker_symval_t symval; 1355 elf_file_t ef = (elf_file_t)file; 1356 const Elf_Sym* symp; 1357 int i, error; 1358 1359 /* Exhaustive search */ 1360 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1361 if (symp->st_value != 0 && 1362 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1363 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) { 1364 error = link_elf_symbol_values(file, 1365 (c_linker_sym_t)symp, &symval); 1366 if (error) 1367 return (error); 1368 error = callback(file, i, &symval, opaque); 1369 if (error) 1370 return (error); 1371 } 1372 } 1373 return (0); 1374 } 1375 1376 static void 1377 elf_obj_cleanup_globals_cache(elf_file_t ef) 1378 { 1379 Elf_Sym *sym; 1380 Elf_Size i; 1381 1382 for (i = 0; i < ef->ddbsymcnt; i++) { 1383 sym = ef->ddbsymtab + i; 1384 if (sym->st_shndx == SHN_FBSD_CACHED) { 1385 sym->st_shndx = SHN_UNDEF; 1386 sym->st_value = 0; 1387 } 1388 } 1389 } 1390 1391 /* 1392 * Symbol lookup function that can be used when the symbol index is known (ie 1393 * in relocations). It uses the symbol index instead of doing a fully fledged 1394 * hash table based lookup when such is valid. For example for local symbols. 1395 * This is not only more efficient, it's also more correct. It's not always 1396 * the case that the symbol can be found through the hash table. 1397 */ 1398 static int 1399 elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res) 1400 { 1401 elf_file_t ef = (elf_file_t)lf; 1402 Elf_Sym *sym; 1403 const char *symbol; 1404 Elf_Addr res1; 1405 1406 /* Don't even try to lookup the symbol if the index is bogus. */ 1407 if (symidx >= ef->ddbsymcnt) { 1408 *res = 0; 1409 return (EINVAL); 1410 } 1411 1412 sym = ef->ddbsymtab + symidx; 1413 1414 /* Quick answer if there is a definition included. */ 1415 if (sym->st_shndx != SHN_UNDEF) { 1416 res1 = (Elf_Addr)sym->st_value; 1417 if (ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC) 1418 res1 = ((Elf_Addr (*)(void))res1)(); 1419 *res = res1; 1420 return (0); 1421 } 1422 1423 /* If we get here, then it is undefined and needs a lookup. */ 1424 switch (ELF_ST_BIND(sym->st_info)) { 1425 case STB_LOCAL: 1426 /* Local, but undefined? huh? */ 1427 *res = 0; 1428 return (EINVAL); 1429 1430 case STB_GLOBAL: 1431 case STB_WEAK: 1432 /* Relative to Data or Function name */ 1433 symbol = ef->ddbstrtab + sym->st_name; 1434 1435 /* Force a lookup failure if the symbol name is bogus. */ 1436 if (*symbol == 0) { 1437 *res = 0; 1438 return (EINVAL); 1439 } 1440 res1 = (Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps); 1441 1442 /* 1443 * Cache global lookups during module relocation. The failure 1444 * case is particularly expensive for callers, who must scan 1445 * through the entire globals table doing strcmp(). Cache to 1446 * avoid doing such work repeatedly. 1447 * 1448 * After relocation is complete, undefined globals will be 1449 * restored to SHN_UNDEF in elf_obj_cleanup_globals_cache(), 1450 * above. 1451 */ 1452 if (res1 != 0) { 1453 sym->st_shndx = SHN_FBSD_CACHED; 1454 sym->st_value = res1; 1455 *res = res1; 1456 return (0); 1457 } else if (ELF_ST_BIND(sym->st_info) == STB_WEAK) { 1458 sym->st_value = 0; 1459 *res = 0; 1460 return (0); 1461 } 1462 return (EINVAL); 1463 1464 default: 1465 return (EINVAL); 1466 } 1467 } 1468 1469 static void 1470 link_elf_fix_link_set(elf_file_t ef) 1471 { 1472 static const char startn[] = "__start_"; 1473 static const char stopn[] = "__stop_"; 1474 Elf_Sym *sym; 1475 const char *sym_name, *linkset_name; 1476 Elf_Addr startp, stopp; 1477 Elf_Size symidx; 1478 int start, i; 1479 1480 startp = stopp = 0; 1481 for (symidx = 1 /* zero entry is special */; 1482 symidx < ef->ddbsymcnt; symidx++) { 1483 sym = ef->ddbsymtab + symidx; 1484 if (sym->st_shndx != SHN_UNDEF) 1485 continue; 1486 1487 sym_name = ef->ddbstrtab + sym->st_name; 1488 if (strncmp(sym_name, startn, sizeof(startn) - 1) == 0) { 1489 start = 1; 1490 linkset_name = sym_name + sizeof(startn) - 1; 1491 } 1492 else if (strncmp(sym_name, stopn, sizeof(stopn) - 1) == 0) { 1493 start = 0; 1494 linkset_name = sym_name + sizeof(stopn) - 1; 1495 } 1496 else 1497 continue; 1498 1499 for (i = 0; i < ef->nprogtab; i++) { 1500 if (strcmp(ef->progtab[i].name, linkset_name) == 0) { 1501 startp = (Elf_Addr)ef->progtab[i].addr; 1502 stopp = (Elf_Addr)(startp + ef->progtab[i].size); 1503 break; 1504 } 1505 } 1506 if (i == ef->nprogtab) 1507 continue; 1508 1509 sym->st_value = start ? startp : stopp; 1510 sym->st_shndx = i; 1511 } 1512 } 1513 1514 static int 1515 link_elf_reloc_local(linker_file_t lf, bool ifuncs) 1516 { 1517 elf_file_t ef = (elf_file_t)lf; 1518 const Elf_Rel *rellim; 1519 const Elf_Rel *rel; 1520 const Elf_Rela *relalim; 1521 const Elf_Rela *rela; 1522 const Elf_Sym *sym; 1523 Elf_Addr base; 1524 int i; 1525 Elf_Size symidx; 1526 1527 link_elf_fix_link_set(ef); 1528 1529 /* Perform relocations without addend if there are any: */ 1530 for (i = 0; i < ef->nreltab; i++) { 1531 rel = ef->reltab[i].rel; 1532 if (rel == NULL) { 1533 link_elf_error(ef->lf.filename, "lost a reltab"); 1534 return (ENOEXEC); 1535 } 1536 rellim = rel + ef->reltab[i].nrel; 1537 base = findbase(ef, ef->reltab[i].sec); 1538 if (base == 0) { 1539 link_elf_error(ef->lf.filename, "lost base for reltab"); 1540 return (ENOEXEC); 1541 } 1542 for ( ; rel < rellim; rel++) { 1543 symidx = ELF_R_SYM(rel->r_info); 1544 if (symidx >= ef->ddbsymcnt) 1545 continue; 1546 sym = ef->ddbsymtab + symidx; 1547 /* Only do local relocs */ 1548 if (ELF_ST_BIND(sym->st_info) != STB_LOCAL) 1549 continue; 1550 if ((ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC || 1551 elf_is_ifunc_reloc(rel->r_info)) == ifuncs) 1552 elf_reloc_local(lf, base, rel, ELF_RELOC_REL, 1553 elf_obj_lookup); 1554 } 1555 } 1556 1557 /* Perform relocations with addend if there are any: */ 1558 for (i = 0; i < ef->nrelatab; i++) { 1559 rela = ef->relatab[i].rela; 1560 if (rela == NULL) { 1561 link_elf_error(ef->lf.filename, "lost a relatab!"); 1562 return (ENOEXEC); 1563 } 1564 relalim = rela + ef->relatab[i].nrela; 1565 base = findbase(ef, ef->relatab[i].sec); 1566 if (base == 0) { 1567 link_elf_error(ef->lf.filename, "lost base for reltab"); 1568 return (ENOEXEC); 1569 } 1570 for ( ; rela < relalim; rela++) { 1571 symidx = ELF_R_SYM(rela->r_info); 1572 if (symidx >= ef->ddbsymcnt) 1573 continue; 1574 sym = ef->ddbsymtab + symidx; 1575 /* Only do local relocs */ 1576 if (ELF_ST_BIND(sym->st_info) != STB_LOCAL) 1577 continue; 1578 if ((ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC || 1579 elf_is_ifunc_reloc(rela->r_info)) == ifuncs) 1580 elf_reloc_local(lf, base, rela, ELF_RELOC_RELA, 1581 elf_obj_lookup); 1582 } 1583 } 1584 return (0); 1585 } 1586 1587 static long 1588 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab) 1589 { 1590 elf_file_t ef = (elf_file_t)lf; 1591 1592 *symtab = ef->ddbsymtab; 1593 1594 if (*symtab == NULL) 1595 return (0); 1596 1597 return (ef->ddbsymcnt); 1598 } 1599 1600 static long 1601 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab) 1602 { 1603 elf_file_t ef = (elf_file_t)lf; 1604 1605 *strtab = ef->ddbstrtab; 1606 1607 if (*strtab == NULL) 1608 return (0); 1609 1610 return (ef->ddbstrcnt); 1611 }
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