Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/kern/link_elf_obj.c
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1 /*- 2 * Copyright (c) 1998-2000 Doug Rabson 3 * Copyright (c) 2004 Peter Wemm 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 */ 27 28 #include <sys/cdefs.h> 29 __FBSDID("$FreeBSD$"); 30 31 #include "opt_ddb.h" 32 33 #include <sys/param.h> 34 #include <sys/systm.h> 35 #include <sys/kernel.h> 36 #include <sys/lock.h> 37 #include <sys/malloc.h> 38 #include <sys/mutex.h> 39 #include <sys/mount.h> 40 #include <sys/proc.h> 41 #include <sys/namei.h> 42 #include <sys/fcntl.h> 43 #include <sys/vnode.h> 44 #include <sys/linker.h> 45 46 #include <machine/elf.h> 47 48 #include <net/vnet.h> 49 50 #include <security/mac/mac_framework.h> 51 52 #include <vm/vm.h> 53 #include <vm/vm_param.h> 54 #include <vm/vm_object.h> 55 #include <vm/vm_kern.h> 56 #include <vm/vm_extern.h> 57 #include <vm/pmap.h> 58 #include <vm/vm_map.h> 59 60 #include <sys/link_elf.h> 61 62 #ifdef DDB_CTF 63 #include <sys/zlib.h> 64 #endif 65 66 #include "linker_if.h" 67 68 typedef struct { 69 void *addr; 70 Elf_Off size; 71 int flags; 72 int sec; /* Original section */ 73 char *name; 74 } Elf_progent; 75 76 typedef struct { 77 Elf_Rel *rel; 78 int nrel; 79 int sec; 80 } Elf_relent; 81 82 typedef struct { 83 Elf_Rela *rela; 84 int nrela; 85 int sec; 86 } Elf_relaent; 87 88 89 typedef struct elf_file { 90 struct linker_file lf; /* Common fields */ 91 92 int preloaded; 93 caddr_t address; /* Relocation address */ 94 vm_object_t object; /* VM object to hold file pages */ 95 Elf_Shdr *e_shdr; 96 97 Elf_progent *progtab; 98 int nprogtab; 99 100 Elf_relaent *relatab; 101 int nrelatab; 102 103 Elf_relent *reltab; 104 int nreltab; 105 106 Elf_Sym *ddbsymtab; /* The symbol table we are using */ 107 long ddbsymcnt; /* Number of symbols */ 108 caddr_t ddbstrtab; /* String table */ 109 long ddbstrcnt; /* number of bytes in string table */ 110 111 caddr_t shstrtab; /* Section name string table */ 112 long shstrcnt; /* number of bytes in string table */ 113 114 caddr_t ctftab; /* CTF table */ 115 long ctfcnt; /* number of bytes in CTF table */ 116 caddr_t ctfoff; /* CTF offset table */ 117 caddr_t typoff; /* Type offset table */ 118 long typlen; /* Number of type entries. */ 119 120 } *elf_file_t; 121 122 #include <kern/kern_ctf.c> 123 124 static int link_elf_link_preload(linker_class_t cls, 125 const char *, linker_file_t *); 126 static int link_elf_link_preload_finish(linker_file_t); 127 static int link_elf_load_file(linker_class_t, const char *, linker_file_t *); 128 static int link_elf_lookup_symbol(linker_file_t, const char *, 129 c_linker_sym_t *); 130 static int link_elf_symbol_values(linker_file_t, c_linker_sym_t, 131 linker_symval_t *); 132 static int link_elf_search_symbol(linker_file_t, caddr_t value, 133 c_linker_sym_t *sym, long *diffp); 134 135 static void link_elf_unload_file(linker_file_t); 136 static int link_elf_lookup_set(linker_file_t, const char *, 137 void ***, void ***, int *); 138 static int link_elf_each_function_name(linker_file_t, 139 int (*)(const char *, void *), void *); 140 static int link_elf_each_function_nameval(linker_file_t, 141 linker_function_nameval_callback_t, 142 void *); 143 static int link_elf_reloc_local(linker_file_t, bool); 144 static long link_elf_symtab_get(linker_file_t, const Elf_Sym **); 145 static long link_elf_strtab_get(linker_file_t, caddr_t *); 146 147 static int elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps, 148 Elf_Addr *); 149 150 static kobj_method_t link_elf_methods[] = { 151 KOBJMETHOD(linker_lookup_symbol, link_elf_lookup_symbol), 152 KOBJMETHOD(linker_symbol_values, link_elf_symbol_values), 153 KOBJMETHOD(linker_search_symbol, link_elf_search_symbol), 154 KOBJMETHOD(linker_unload, link_elf_unload_file), 155 KOBJMETHOD(linker_load_file, link_elf_load_file), 156 KOBJMETHOD(linker_link_preload, link_elf_link_preload), 157 KOBJMETHOD(linker_link_preload_finish, link_elf_link_preload_finish), 158 KOBJMETHOD(linker_lookup_set, link_elf_lookup_set), 159 KOBJMETHOD(linker_each_function_name, link_elf_each_function_name), 160 KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval), 161 KOBJMETHOD(linker_ctf_get, link_elf_ctf_get), 162 KOBJMETHOD(linker_symtab_get, link_elf_symtab_get), 163 KOBJMETHOD(linker_strtab_get, link_elf_strtab_get), 164 { 0, 0 } 165 }; 166 167 static struct linker_class link_elf_class = { 168 #if ELF_TARG_CLASS == ELFCLASS32 169 "elf32_obj", 170 #else 171 "elf64_obj", 172 #endif 173 link_elf_methods, sizeof(struct elf_file) 174 }; 175 176 static int relocate_file(elf_file_t ef); 177 static void elf_obj_cleanup_globals_cache(elf_file_t); 178 179 static void 180 link_elf_error(const char *filename, const char *s) 181 { 182 if (filename == NULL) 183 printf("kldload: %s\n", s); 184 else 185 printf("kldload: %s: %s\n", filename, s); 186 } 187 188 static void 189 link_elf_init(void *arg) 190 { 191 192 linker_add_class(&link_elf_class); 193 } 194 195 SYSINIT(link_elf_obj, SI_SUB_KLD, SI_ORDER_SECOND, link_elf_init, NULL); 196 197 static int 198 link_elf_link_preload(linker_class_t cls, const char *filename, 199 linker_file_t *result) 200 { 201 Elf_Ehdr *hdr; 202 Elf_Shdr *shdr; 203 Elf_Sym *es; 204 void *modptr, *baseptr, *sizeptr; 205 char *type; 206 elf_file_t ef; 207 linker_file_t lf; 208 Elf_Addr off; 209 int error, i, j, pb, ra, rl, shstrindex, symstrindex, symtabindex; 210 211 /* Look to see if we have the file preloaded */ 212 modptr = preload_search_by_name(filename); 213 if (modptr == NULL) 214 return ENOENT; 215 216 type = (char *)preload_search_info(modptr, MODINFO_TYPE); 217 baseptr = preload_search_info(modptr, MODINFO_ADDR); 218 sizeptr = preload_search_info(modptr, MODINFO_SIZE); 219 hdr = (Elf_Ehdr *)preload_search_info(modptr, MODINFO_METADATA | 220 MODINFOMD_ELFHDR); 221 shdr = (Elf_Shdr *)preload_search_info(modptr, MODINFO_METADATA | 222 MODINFOMD_SHDR); 223 if (type == NULL || (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) 224 " obj module") != 0 && 225 strcmp(type, "elf obj module") != 0)) { 226 return (EFTYPE); 227 } 228 if (baseptr == NULL || sizeptr == NULL || hdr == NULL || 229 shdr == NULL) 230 return (EINVAL); 231 232 lf = linker_make_file(filename, &link_elf_class); 233 if (lf == NULL) 234 return (ENOMEM); 235 236 ef = (elf_file_t)lf; 237 ef->preloaded = 1; 238 ef->address = *(caddr_t *)baseptr; 239 lf->address = *(caddr_t *)baseptr; 240 lf->size = *(size_t *)sizeptr; 241 242 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS || 243 hdr->e_ident[EI_DATA] != ELF_TARG_DATA || 244 hdr->e_ident[EI_VERSION] != EV_CURRENT || 245 hdr->e_version != EV_CURRENT || 246 hdr->e_type != ET_REL || 247 hdr->e_machine != ELF_TARG_MACH) { 248 error = EFTYPE; 249 goto out; 250 } 251 ef->e_shdr = shdr; 252 253 /* Scan the section header for information and table sizing. */ 254 symtabindex = -1; 255 symstrindex = -1; 256 for (i = 0; i < hdr->e_shnum; i++) { 257 switch (shdr[i].sh_type) { 258 case SHT_PROGBITS: 259 case SHT_NOBITS: 260 #ifdef __amd64__ 261 case SHT_X86_64_UNWIND: 262 #endif 263 /* Ignore sections not loaded by the loader. */ 264 if (shdr[i].sh_addr == 0) 265 break; 266 ef->nprogtab++; 267 break; 268 case SHT_SYMTAB: 269 symtabindex = i; 270 symstrindex = shdr[i].sh_link; 271 break; 272 case SHT_REL: 273 /* 274 * Ignore relocation tables for sections not 275 * loaded by the loader. 276 */ 277 if (shdr[shdr[i].sh_info].sh_addr == 0) 278 break; 279 ef->nreltab++; 280 break; 281 case SHT_RELA: 282 if (shdr[shdr[i].sh_info].sh_addr == 0) 283 break; 284 ef->nrelatab++; 285 break; 286 } 287 } 288 289 shstrindex = hdr->e_shstrndx; 290 if (ef->nprogtab == 0 || symstrindex < 0 || 291 symstrindex >= hdr->e_shnum || 292 shdr[symstrindex].sh_type != SHT_STRTAB || shstrindex == 0 || 293 shstrindex >= hdr->e_shnum || 294 shdr[shstrindex].sh_type != SHT_STRTAB) { 295 printf("%s: bad/missing section headers\n", filename); 296 error = ENOEXEC; 297 goto out; 298 } 299 300 /* Allocate space for tracking the load chunks */ 301 if (ef->nprogtab != 0) 302 ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab), 303 M_LINKER, M_WAITOK | M_ZERO); 304 if (ef->nreltab != 0) 305 ef->reltab = malloc(ef->nreltab * sizeof(*ef->reltab), 306 M_LINKER, M_WAITOK | M_ZERO); 307 if (ef->nrelatab != 0) 308 ef->relatab = malloc(ef->nrelatab * sizeof(*ef->relatab), 309 M_LINKER, M_WAITOK | M_ZERO); 310 if ((ef->nprogtab != 0 && ef->progtab == NULL) || 311 (ef->nreltab != 0 && ef->reltab == NULL) || 312 (ef->nrelatab != 0 && ef->relatab == NULL)) { 313 error = ENOMEM; 314 goto out; 315 } 316 317 /* XXX, relocate the sh_addr fields saved by the loader. */ 318 off = 0; 319 for (i = 0; i < hdr->e_shnum; i++) { 320 if (shdr[i].sh_addr != 0 && (off == 0 || shdr[i].sh_addr < off)) 321 off = shdr[i].sh_addr; 322 } 323 for (i = 0; i < hdr->e_shnum; i++) { 324 if (shdr[i].sh_addr != 0) 325 shdr[i].sh_addr = shdr[i].sh_addr - off + 326 (Elf_Addr)ef->address; 327 } 328 329 ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym); 330 ef->ddbsymtab = (Elf_Sym *)shdr[symtabindex].sh_addr; 331 ef->ddbstrcnt = shdr[symstrindex].sh_size; 332 ef->ddbstrtab = (char *)shdr[symstrindex].sh_addr; 333 ef->shstrcnt = shdr[shstrindex].sh_size; 334 ef->shstrtab = (char *)shdr[shstrindex].sh_addr; 335 336 /* Now fill out progtab and the relocation tables. */ 337 pb = 0; 338 rl = 0; 339 ra = 0; 340 for (i = 0; i < hdr->e_shnum; i++) { 341 switch (shdr[i].sh_type) { 342 case SHT_PROGBITS: 343 case SHT_NOBITS: 344 #ifdef __amd64__ 345 case SHT_X86_64_UNWIND: 346 #endif 347 if (shdr[i].sh_addr == 0) 348 break; 349 ef->progtab[pb].addr = (void *)shdr[i].sh_addr; 350 if (shdr[i].sh_type == SHT_PROGBITS) 351 ef->progtab[pb].name = "<<PROGBITS>>"; 352 #ifdef __amd64__ 353 else if (shdr[i].sh_type == SHT_X86_64_UNWIND) 354 ef->progtab[pb].name = "<<UNWIND>>"; 355 #endif 356 else 357 ef->progtab[pb].name = "<<NOBITS>>"; 358 ef->progtab[pb].size = shdr[i].sh_size; 359 ef->progtab[pb].sec = i; 360 if (ef->shstrtab && shdr[i].sh_name != 0) 361 ef->progtab[pb].name = 362 ef->shstrtab + shdr[i].sh_name; 363 if (ef->progtab[pb].name != NULL && 364 !strcmp(ef->progtab[pb].name, DPCPU_SETNAME)) { 365 void *dpcpu; 366 367 dpcpu = dpcpu_alloc(shdr[i].sh_size); 368 if (dpcpu == NULL) { 369 printf("%s: pcpu module space is out " 370 "of space; cannot allocate %#jx " 371 "for %s\n", __func__, 372 (uintmax_t)shdr[i].sh_size, 373 filename); 374 error = ENOSPC; 375 goto out; 376 } 377 memcpy(dpcpu, ef->progtab[pb].addr, 378 ef->progtab[pb].size); 379 dpcpu_copy(dpcpu, shdr[i].sh_size); 380 ef->progtab[pb].addr = dpcpu; 381 #ifdef VIMAGE 382 } else if (ef->progtab[pb].name != NULL && 383 !strcmp(ef->progtab[pb].name, VNET_SETNAME)) { 384 void *vnet_data; 385 386 vnet_data = vnet_data_alloc(shdr[i].sh_size); 387 if (vnet_data == NULL) { 388 printf("%s: vnet module space is out " 389 "of space; cannot allocate %#jx " 390 "for %s\n", __func__, 391 (uintmax_t)shdr[i].sh_size, 392 filename); 393 error = ENOSPC; 394 goto out; 395 } 396 memcpy(vnet_data, ef->progtab[pb].addr, 397 ef->progtab[pb].size); 398 vnet_data_copy(vnet_data, shdr[i].sh_size); 399 ef->progtab[pb].addr = vnet_data; 400 #endif 401 } else if (ef->progtab[pb].name != NULL && 402 !strcmp(ef->progtab[pb].name, ".ctors")) { 403 lf->ctors_addr = ef->progtab[pb].addr; 404 lf->ctors_size = shdr[i].sh_size; 405 } 406 407 /* Update all symbol values with the offset. */ 408 for (j = 0; j < ef->ddbsymcnt; j++) { 409 es = &ef->ddbsymtab[j]; 410 if (es->st_shndx != i) 411 continue; 412 es->st_value += (Elf_Addr)ef->progtab[pb].addr; 413 } 414 pb++; 415 break; 416 case SHT_REL: 417 if (shdr[shdr[i].sh_info].sh_addr == 0) 418 break; 419 ef->reltab[rl].rel = (Elf_Rel *)shdr[i].sh_addr; 420 ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel); 421 ef->reltab[rl].sec = shdr[i].sh_info; 422 rl++; 423 break; 424 case SHT_RELA: 425 if (shdr[shdr[i].sh_info].sh_addr == 0) 426 break; 427 ef->relatab[ra].rela = (Elf_Rela *)shdr[i].sh_addr; 428 ef->relatab[ra].nrela = 429 shdr[i].sh_size / sizeof(Elf_Rela); 430 ef->relatab[ra].sec = shdr[i].sh_info; 431 ra++; 432 break; 433 } 434 } 435 if (pb != ef->nprogtab) { 436 printf("%s: lost progbits\n", filename); 437 error = ENOEXEC; 438 goto out; 439 } 440 if (rl != ef->nreltab) { 441 printf("%s: lost reltab\n", filename); 442 error = ENOEXEC; 443 goto out; 444 } 445 if (ra != ef->nrelatab) { 446 printf("%s: lost relatab\n", filename); 447 error = ENOEXEC; 448 goto out; 449 } 450 451 /* Local intra-module relocations */ 452 error = link_elf_reloc_local(lf, false); 453 if (error != 0) 454 goto out; 455 *result = lf; 456 return (0); 457 458 out: 459 /* preload not done this way */ 460 linker_file_unload(lf, LINKER_UNLOAD_FORCE); 461 return (error); 462 } 463 464 static void 465 link_elf_invoke_ctors(caddr_t addr, size_t size) 466 { 467 void (**ctor)(void); 468 size_t i, cnt; 469 470 if (addr == NULL || size == 0) 471 return; 472 cnt = size / sizeof(*ctor); 473 ctor = (void *)addr; 474 for (i = 0; i < cnt; i++) { 475 if (ctor[i] != NULL) 476 (*ctor[i])(); 477 } 478 } 479 480 static int 481 link_elf_link_preload_finish(linker_file_t lf) 482 { 483 elf_file_t ef; 484 int error; 485 486 ef = (elf_file_t)lf; 487 error = relocate_file(ef); 488 if (error) 489 return (error); 490 491 /* Notify MD code that a module is being loaded. */ 492 error = elf_cpu_load_file(lf); 493 if (error) 494 return (error); 495 496 #if defined(__i386__) || defined(__amd64__) 497 /* Now ifuncs. */ 498 error = link_elf_reloc_local(lf, true); 499 if (error != 0) 500 return (error); 501 #endif 502 503 /* Invoke .ctors */ 504 link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size); 505 return (0); 506 } 507 508 static int 509 link_elf_load_file(linker_class_t cls, const char *filename, 510 linker_file_t *result) 511 { 512 struct nameidata nd; 513 struct thread *td = curthread; /* XXX */ 514 Elf_Ehdr *hdr; 515 Elf_Shdr *shdr; 516 Elf_Sym *es; 517 int nbytes, i, j; 518 vm_offset_t mapbase; 519 size_t mapsize; 520 int error = 0; 521 ssize_t resid; 522 int flags; 523 elf_file_t ef; 524 linker_file_t lf; 525 int symtabindex; 526 int symstrindex; 527 int shstrindex; 528 int nsym; 529 int pb, rl, ra; 530 int alignmask; 531 532 shdr = NULL; 533 lf = NULL; 534 mapsize = 0; 535 hdr = NULL; 536 537 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td); 538 flags = FREAD; 539 error = vn_open(&nd, &flags, 0, NULL); 540 if (error) 541 return error; 542 NDFREE(&nd, NDF_ONLY_PNBUF); 543 if (nd.ni_vp->v_type != VREG) { 544 error = ENOEXEC; 545 goto out; 546 } 547 #ifdef MAC 548 error = mac_kld_check_load(td->td_ucred, nd.ni_vp); 549 if (error) { 550 goto out; 551 } 552 #endif 553 554 /* Read the elf header from the file. */ 555 hdr = malloc(sizeof(*hdr), M_LINKER, M_WAITOK); 556 error = vn_rdwr(UIO_READ, nd.ni_vp, (void *)hdr, sizeof(*hdr), 0, 557 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 558 &resid, td); 559 if (error) 560 goto out; 561 if (resid != 0){ 562 error = ENOEXEC; 563 goto out; 564 } 565 566 if (!IS_ELF(*hdr)) { 567 error = ENOEXEC; 568 goto out; 569 } 570 571 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS 572 || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) { 573 link_elf_error(filename, "Unsupported file layout"); 574 error = ENOEXEC; 575 goto out; 576 } 577 if (hdr->e_ident[EI_VERSION] != EV_CURRENT 578 || hdr->e_version != EV_CURRENT) { 579 link_elf_error(filename, "Unsupported file version"); 580 error = ENOEXEC; 581 goto out; 582 } 583 if (hdr->e_type != ET_REL) { 584 error = ENOSYS; 585 goto out; 586 } 587 if (hdr->e_machine != ELF_TARG_MACH) { 588 link_elf_error(filename, "Unsupported machine"); 589 error = ENOEXEC; 590 goto out; 591 } 592 593 lf = linker_make_file(filename, &link_elf_class); 594 if (!lf) { 595 error = ENOMEM; 596 goto out; 597 } 598 ef = (elf_file_t) lf; 599 ef->nprogtab = 0; 600 ef->e_shdr = 0; 601 ef->nreltab = 0; 602 ef->nrelatab = 0; 603 604 /* Allocate and read in the section header */ 605 nbytes = hdr->e_shnum * hdr->e_shentsize; 606 if (nbytes == 0 || hdr->e_shoff == 0 || 607 hdr->e_shentsize != sizeof(Elf_Shdr)) { 608 error = ENOEXEC; 609 goto out; 610 } 611 shdr = malloc(nbytes, M_LINKER, M_WAITOK); 612 ef->e_shdr = shdr; 613 error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)shdr, nbytes, hdr->e_shoff, 614 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, &resid, td); 615 if (error) 616 goto out; 617 if (resid) { 618 error = ENOEXEC; 619 goto out; 620 } 621 622 /* Scan the section header for information and table sizing. */ 623 nsym = 0; 624 symtabindex = -1; 625 symstrindex = -1; 626 for (i = 0; i < hdr->e_shnum; i++) { 627 if (shdr[i].sh_size == 0) 628 continue; 629 switch (shdr[i].sh_type) { 630 case SHT_PROGBITS: 631 case SHT_NOBITS: 632 #ifdef __amd64__ 633 case SHT_X86_64_UNWIND: 634 #endif 635 if ((shdr[i].sh_flags & SHF_ALLOC) == 0) 636 break; 637 ef->nprogtab++; 638 break; 639 case SHT_SYMTAB: 640 nsym++; 641 symtabindex = i; 642 symstrindex = shdr[i].sh_link; 643 break; 644 case SHT_REL: 645 /* 646 * Ignore relocation tables for unallocated 647 * sections. 648 */ 649 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0) 650 break; 651 ef->nreltab++; 652 break; 653 case SHT_RELA: 654 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0) 655 break; 656 ef->nrelatab++; 657 break; 658 case SHT_STRTAB: 659 break; 660 } 661 } 662 if (ef->nprogtab == 0) { 663 link_elf_error(filename, "file has no contents"); 664 error = ENOEXEC; 665 goto out; 666 } 667 if (nsym != 1) { 668 /* Only allow one symbol table for now */ 669 link_elf_error(filename, "file has no valid symbol table"); 670 error = ENOEXEC; 671 goto out; 672 } 673 if (symstrindex < 0 || symstrindex > hdr->e_shnum || 674 shdr[symstrindex].sh_type != SHT_STRTAB) { 675 link_elf_error(filename, "file has invalid symbol strings"); 676 error = ENOEXEC; 677 goto out; 678 } 679 680 /* Allocate space for tracking the load chunks */ 681 if (ef->nprogtab != 0) 682 ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab), 683 M_LINKER, M_WAITOK | M_ZERO); 684 if (ef->nreltab != 0) 685 ef->reltab = malloc(ef->nreltab * sizeof(*ef->reltab), 686 M_LINKER, M_WAITOK | M_ZERO); 687 if (ef->nrelatab != 0) 688 ef->relatab = malloc(ef->nrelatab * sizeof(*ef->relatab), 689 M_LINKER, M_WAITOK | M_ZERO); 690 691 if (symtabindex == -1) { 692 link_elf_error(filename, "lost symbol table index"); 693 error = ENOEXEC; 694 goto out; 695 } 696 /* Allocate space for and load the symbol table */ 697 ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym); 698 ef->ddbsymtab = malloc(shdr[symtabindex].sh_size, M_LINKER, M_WAITOK); 699 error = vn_rdwr(UIO_READ, nd.ni_vp, (void *)ef->ddbsymtab, 700 shdr[symtabindex].sh_size, shdr[symtabindex].sh_offset, 701 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 702 &resid, td); 703 if (error) 704 goto out; 705 if (resid != 0){ 706 error = EINVAL; 707 goto out; 708 } 709 710 /* Allocate space for and load the symbol strings */ 711 ef->ddbstrcnt = shdr[symstrindex].sh_size; 712 ef->ddbstrtab = malloc(shdr[symstrindex].sh_size, M_LINKER, M_WAITOK); 713 error = vn_rdwr(UIO_READ, nd.ni_vp, ef->ddbstrtab, 714 shdr[symstrindex].sh_size, shdr[symstrindex].sh_offset, 715 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 716 &resid, td); 717 if (error) 718 goto out; 719 if (resid != 0){ 720 error = EINVAL; 721 goto out; 722 } 723 724 /* Do we have a string table for the section names? */ 725 shstrindex = -1; 726 if (hdr->e_shstrndx != 0 && 727 shdr[hdr->e_shstrndx].sh_type == SHT_STRTAB) { 728 shstrindex = hdr->e_shstrndx; 729 ef->shstrcnt = shdr[shstrindex].sh_size; 730 ef->shstrtab = malloc(shdr[shstrindex].sh_size, M_LINKER, 731 M_WAITOK); 732 error = vn_rdwr(UIO_READ, nd.ni_vp, ef->shstrtab, 733 shdr[shstrindex].sh_size, shdr[shstrindex].sh_offset, 734 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 735 &resid, td); 736 if (error) 737 goto out; 738 if (resid != 0){ 739 error = EINVAL; 740 goto out; 741 } 742 } 743 744 /* Size up code/data(progbits) and bss(nobits). */ 745 alignmask = 0; 746 for (i = 0; i < hdr->e_shnum; i++) { 747 if (shdr[i].sh_size == 0) 748 continue; 749 switch (shdr[i].sh_type) { 750 case SHT_PROGBITS: 751 case SHT_NOBITS: 752 #ifdef __amd64__ 753 case SHT_X86_64_UNWIND: 754 #endif 755 if ((shdr[i].sh_flags & SHF_ALLOC) == 0) 756 break; 757 alignmask = shdr[i].sh_addralign - 1; 758 mapsize += alignmask; 759 mapsize &= ~alignmask; 760 mapsize += shdr[i].sh_size; 761 break; 762 } 763 } 764 765 /* 766 * We know how much space we need for the text/data/bss/etc. 767 * This stuff needs to be in a single chunk so that profiling etc 768 * can get the bounds and gdb can associate offsets with modules 769 */ 770 ef->object = vm_object_allocate(OBJT_DEFAULT, 771 round_page(mapsize) >> PAGE_SHIFT); 772 if (ef->object == NULL) { 773 error = ENOMEM; 774 goto out; 775 } 776 ef->address = (caddr_t) vm_map_min(kernel_map); 777 778 /* 779 * In order to satisfy amd64's architectural requirements on the 780 * location of code and data in the kernel's address space, request a 781 * mapping that is above the kernel. 782 */ 783 #ifdef __amd64__ 784 mapbase = KERNBASE; 785 #else 786 mapbase = VM_MIN_KERNEL_ADDRESS; 787 #endif 788 error = vm_map_find(kernel_map, ef->object, 0, &mapbase, 789 round_page(mapsize), 0, VMFS_OPTIMAL_SPACE, VM_PROT_ALL, 790 VM_PROT_ALL, 0); 791 if (error) { 792 vm_object_deallocate(ef->object); 793 ef->object = 0; 794 goto out; 795 } 796 797 /* Wire the pages */ 798 error = vm_map_wire(kernel_map, mapbase, 799 mapbase + round_page(mapsize), 800 VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES); 801 if (error != KERN_SUCCESS) { 802 error = ENOMEM; 803 goto out; 804 } 805 806 /* Inform the kld system about the situation */ 807 lf->address = ef->address = (caddr_t)mapbase; 808 lf->size = mapsize; 809 810 /* 811 * Now load code/data(progbits), zero bss(nobits), allocate space for 812 * and load relocs 813 */ 814 pb = 0; 815 rl = 0; 816 ra = 0; 817 alignmask = 0; 818 for (i = 0; i < hdr->e_shnum; i++) { 819 if (shdr[i].sh_size == 0) 820 continue; 821 switch (shdr[i].sh_type) { 822 case SHT_PROGBITS: 823 case SHT_NOBITS: 824 #ifdef __amd64__ 825 case SHT_X86_64_UNWIND: 826 #endif 827 if ((shdr[i].sh_flags & SHF_ALLOC) == 0) 828 break; 829 alignmask = shdr[i].sh_addralign - 1; 830 mapbase += alignmask; 831 mapbase &= ~alignmask; 832 if (ef->shstrtab != NULL && shdr[i].sh_name != 0) { 833 ef->progtab[pb].name = 834 ef->shstrtab + shdr[i].sh_name; 835 if (!strcmp(ef->progtab[pb].name, ".ctors")) { 836 lf->ctors_addr = (caddr_t)mapbase; 837 lf->ctors_size = shdr[i].sh_size; 838 } 839 } else if (shdr[i].sh_type == SHT_PROGBITS) 840 ef->progtab[pb].name = "<<PROGBITS>>"; 841 #ifdef __amd64__ 842 else if (shdr[i].sh_type == SHT_X86_64_UNWIND) 843 ef->progtab[pb].name = "<<UNWIND>>"; 844 #endif 845 else 846 ef->progtab[pb].name = "<<NOBITS>>"; 847 if (ef->progtab[pb].name != NULL && 848 !strcmp(ef->progtab[pb].name, DPCPU_SETNAME)) { 849 ef->progtab[pb].addr = 850 dpcpu_alloc(shdr[i].sh_size); 851 if (ef->progtab[pb].addr == NULL) { 852 printf("%s: pcpu module space is out " 853 "of space; cannot allocate %#jx " 854 "for %s\n", __func__, 855 (uintmax_t)shdr[i].sh_size, 856 filename); 857 } 858 } 859 #ifdef VIMAGE 860 else if (ef->progtab[pb].name != NULL && 861 !strcmp(ef->progtab[pb].name, VNET_SETNAME)) { 862 ef->progtab[pb].addr = 863 vnet_data_alloc(shdr[i].sh_size); 864 if (ef->progtab[pb].addr == NULL) { 865 printf("%s: vnet module space is out " 866 "of space; cannot allocate %#jx " 867 "for %s\n", __func__, 868 (uintmax_t)shdr[i].sh_size, 869 filename); 870 } 871 } 872 #endif 873 else 874 ef->progtab[pb].addr = 875 (void *)(uintptr_t)mapbase; 876 if (ef->progtab[pb].addr == NULL) { 877 error = ENOSPC; 878 goto out; 879 } 880 ef->progtab[pb].size = shdr[i].sh_size; 881 ef->progtab[pb].sec = i; 882 if (shdr[i].sh_type == SHT_PROGBITS 883 #ifdef __amd64__ 884 || shdr[i].sh_type == SHT_X86_64_UNWIND 885 #endif 886 ) { 887 error = vn_rdwr(UIO_READ, nd.ni_vp, 888 ef->progtab[pb].addr, 889 shdr[i].sh_size, shdr[i].sh_offset, 890 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, 891 NOCRED, &resid, td); 892 if (error) 893 goto out; 894 if (resid != 0){ 895 error = EINVAL; 896 goto out; 897 } 898 /* Initialize the per-cpu or vnet area. */ 899 if (ef->progtab[pb].addr != (void *)mapbase && 900 !strcmp(ef->progtab[pb].name, DPCPU_SETNAME)) 901 dpcpu_copy(ef->progtab[pb].addr, 902 shdr[i].sh_size); 903 #ifdef VIMAGE 904 else if (ef->progtab[pb].addr != 905 (void *)mapbase && 906 !strcmp(ef->progtab[pb].name, VNET_SETNAME)) 907 vnet_data_copy(ef->progtab[pb].addr, 908 shdr[i].sh_size); 909 #endif 910 } else 911 bzero(ef->progtab[pb].addr, shdr[i].sh_size); 912 913 /* Update all symbol values with the offset. */ 914 for (j = 0; j < ef->ddbsymcnt; j++) { 915 es = &ef->ddbsymtab[j]; 916 if (es->st_shndx != i) 917 continue; 918 es->st_value += (Elf_Addr)ef->progtab[pb].addr; 919 } 920 mapbase += shdr[i].sh_size; 921 pb++; 922 break; 923 case SHT_REL: 924 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0) 925 break; 926 ef->reltab[rl].rel = malloc(shdr[i].sh_size, M_LINKER, 927 M_WAITOK); 928 ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel); 929 ef->reltab[rl].sec = shdr[i].sh_info; 930 error = vn_rdwr(UIO_READ, nd.ni_vp, 931 (void *)ef->reltab[rl].rel, 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 rl++; 942 break; 943 case SHT_RELA: 944 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0) 945 break; 946 ef->relatab[ra].rela = malloc(shdr[i].sh_size, M_LINKER, 947 M_WAITOK); 948 ef->relatab[ra].nrela = 949 shdr[i].sh_size / sizeof(Elf_Rela); 950 ef->relatab[ra].sec = shdr[i].sh_info; 951 error = vn_rdwr(UIO_READ, nd.ni_vp, 952 (void *)ef->relatab[ra].rela, 953 shdr[i].sh_size, shdr[i].sh_offset, 954 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 955 &resid, td); 956 if (error) 957 goto out; 958 if (resid != 0){ 959 error = EINVAL; 960 goto out; 961 } 962 ra++; 963 break; 964 } 965 } 966 if (pb != ef->nprogtab) { 967 link_elf_error(filename, "lost progbits"); 968 error = ENOEXEC; 969 goto out; 970 } 971 if (rl != ef->nreltab) { 972 link_elf_error(filename, "lost reltab"); 973 error = ENOEXEC; 974 goto out; 975 } 976 if (ra != ef->nrelatab) { 977 link_elf_error(filename, "lost relatab"); 978 error = ENOEXEC; 979 goto out; 980 } 981 if (mapbase != (vm_offset_t)ef->address + mapsize) { 982 printf( 983 "%s: mapbase 0x%lx != address %p + mapsize 0x%lx (0x%lx)\n", 984 filename != NULL ? filename : "<none>", 985 (u_long)mapbase, ef->address, (u_long)mapsize, 986 (u_long)(vm_offset_t)ef->address + mapsize); 987 error = ENOMEM; 988 goto out; 989 } 990 991 /* Local intra-module relocations */ 992 error = link_elf_reloc_local(lf, false); 993 if (error != 0) 994 goto out; 995 996 /* Pull in dependencies */ 997 VOP_UNLOCK(nd.ni_vp, 0); 998 error = linker_load_dependencies(lf); 999 vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY); 1000 if (error) 1001 goto out; 1002 1003 /* External relocations */ 1004 error = relocate_file(ef); 1005 if (error) 1006 goto out; 1007 1008 /* Notify MD code that a module is being loaded. */ 1009 error = elf_cpu_load_file(lf); 1010 if (error) 1011 goto out; 1012 1013 #if defined(__i386__) || defined(__amd64__) 1014 /* Now ifuncs. */ 1015 error = link_elf_reloc_local(lf, true); 1016 if (error != 0) 1017 goto out; 1018 #endif 1019 1020 /* Invoke .ctors */ 1021 link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size); 1022 1023 *result = lf; 1024 1025 out: 1026 VOP_UNLOCK(nd.ni_vp, 0); 1027 vn_close(nd.ni_vp, FREAD, td->td_ucred, td); 1028 if (error && lf) 1029 linker_file_unload(lf, LINKER_UNLOAD_FORCE); 1030 free(hdr, M_LINKER); 1031 1032 return error; 1033 } 1034 1035 static void 1036 link_elf_unload_file(linker_file_t file) 1037 { 1038 elf_file_t ef = (elf_file_t) file; 1039 int i; 1040 1041 /* Notify MD code that a module is being unloaded. */ 1042 elf_cpu_unload_file(file); 1043 1044 if (ef->progtab) { 1045 for (i = 0; i < ef->nprogtab; i++) { 1046 if (ef->progtab[i].size == 0) 1047 continue; 1048 if (ef->progtab[i].name == NULL) 1049 continue; 1050 if (!strcmp(ef->progtab[i].name, DPCPU_SETNAME)) 1051 dpcpu_free(ef->progtab[i].addr, 1052 ef->progtab[i].size); 1053 #ifdef VIMAGE 1054 else if (!strcmp(ef->progtab[i].name, VNET_SETNAME)) 1055 vnet_data_free(ef->progtab[i].addr, 1056 ef->progtab[i].size); 1057 #endif 1058 } 1059 } 1060 if (ef->preloaded) { 1061 free(ef->reltab, M_LINKER); 1062 free(ef->relatab, M_LINKER); 1063 free(ef->progtab, M_LINKER); 1064 free(ef->ctftab, M_LINKER); 1065 free(ef->ctfoff, M_LINKER); 1066 free(ef->typoff, M_LINKER); 1067 if (file->pathname != NULL) 1068 preload_delete_name(file->pathname); 1069 return; 1070 } 1071 1072 for (i = 0; i < ef->nreltab; i++) 1073 free(ef->reltab[i].rel, M_LINKER); 1074 for (i = 0; i < ef->nrelatab; i++) 1075 free(ef->relatab[i].rela, M_LINKER); 1076 free(ef->reltab, M_LINKER); 1077 free(ef->relatab, M_LINKER); 1078 free(ef->progtab, M_LINKER); 1079 1080 if (ef->object) { 1081 vm_map_remove(kernel_map, (vm_offset_t) ef->address, 1082 (vm_offset_t) ef->address + 1083 (ef->object->size << PAGE_SHIFT)); 1084 } 1085 free(ef->e_shdr, M_LINKER); 1086 free(ef->ddbsymtab, M_LINKER); 1087 free(ef->ddbstrtab, M_LINKER); 1088 free(ef->shstrtab, M_LINKER); 1089 free(ef->ctftab, M_LINKER); 1090 free(ef->ctfoff, M_LINKER); 1091 free(ef->typoff, M_LINKER); 1092 } 1093 1094 static const char * 1095 symbol_name(elf_file_t ef, Elf_Size r_info) 1096 { 1097 const Elf_Sym *ref; 1098 1099 if (ELF_R_SYM(r_info)) { 1100 ref = ef->ddbsymtab + ELF_R_SYM(r_info); 1101 return ef->ddbstrtab + ref->st_name; 1102 } else 1103 return NULL; 1104 } 1105 1106 static Elf_Addr 1107 findbase(elf_file_t ef, int sec) 1108 { 1109 int i; 1110 Elf_Addr base = 0; 1111 1112 for (i = 0; i < ef->nprogtab; i++) { 1113 if (sec == ef->progtab[i].sec) { 1114 base = (Elf_Addr)ef->progtab[i].addr; 1115 break; 1116 } 1117 } 1118 return base; 1119 } 1120 1121 static int 1122 relocate_file(elf_file_t ef) 1123 { 1124 const Elf_Rel *rellim; 1125 const Elf_Rel *rel; 1126 const Elf_Rela *relalim; 1127 const Elf_Rela *rela; 1128 const char *symname; 1129 const Elf_Sym *sym; 1130 int i; 1131 Elf_Size symidx; 1132 Elf_Addr base; 1133 1134 1135 /* Perform relocations without addend if there are any: */ 1136 for (i = 0; i < ef->nreltab; i++) { 1137 rel = ef->reltab[i].rel; 1138 if (rel == NULL) { 1139 link_elf_error(ef->lf.filename, "lost a reltab!"); 1140 return (ENOEXEC); 1141 } 1142 rellim = rel + ef->reltab[i].nrel; 1143 base = findbase(ef, ef->reltab[i].sec); 1144 if (base == 0) { 1145 link_elf_error(ef->lf.filename, "lost base for reltab"); 1146 return (ENOEXEC); 1147 } 1148 for ( ; rel < rellim; rel++) { 1149 symidx = ELF_R_SYM(rel->r_info); 1150 if (symidx >= ef->ddbsymcnt) 1151 continue; 1152 sym = ef->ddbsymtab + symidx; 1153 /* Local relocs are already done */ 1154 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) 1155 continue; 1156 if (elf_reloc(&ef->lf, base, rel, ELF_RELOC_REL, 1157 elf_obj_lookup)) { 1158 symname = symbol_name(ef, rel->r_info); 1159 printf("link_elf_obj: symbol %s undefined\n", 1160 symname); 1161 return (ENOENT); 1162 } 1163 } 1164 } 1165 1166 /* Perform relocations with addend if there are any: */ 1167 for (i = 0; i < ef->nrelatab; i++) { 1168 rela = ef->relatab[i].rela; 1169 if (rela == NULL) { 1170 link_elf_error(ef->lf.filename, "lost a relatab!"); 1171 return (ENOEXEC); 1172 } 1173 relalim = rela + ef->relatab[i].nrela; 1174 base = findbase(ef, ef->relatab[i].sec); 1175 if (base == 0) { 1176 link_elf_error(ef->lf.filename, 1177 "lost base for relatab"); 1178 return (ENOEXEC); 1179 } 1180 for ( ; rela < relalim; rela++) { 1181 symidx = ELF_R_SYM(rela->r_info); 1182 if (symidx >= ef->ddbsymcnt) 1183 continue; 1184 sym = ef->ddbsymtab + symidx; 1185 /* Local relocs are already done */ 1186 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) 1187 continue; 1188 if (elf_reloc(&ef->lf, base, rela, ELF_RELOC_RELA, 1189 elf_obj_lookup)) { 1190 symname = symbol_name(ef, rela->r_info); 1191 printf("link_elf_obj: symbol %s undefined\n", 1192 symname); 1193 return (ENOENT); 1194 } 1195 } 1196 } 1197 1198 /* 1199 * Only clean SHN_FBSD_CACHED for successful return. If we 1200 * modified symbol table for the object but found an 1201 * unresolved symbol, there is no reason to roll back. 1202 */ 1203 elf_obj_cleanup_globals_cache(ef); 1204 1205 return (0); 1206 } 1207 1208 static int 1209 link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym) 1210 { 1211 elf_file_t ef = (elf_file_t) lf; 1212 const Elf_Sym *symp; 1213 const char *strp; 1214 int i; 1215 1216 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1217 strp = ef->ddbstrtab + symp->st_name; 1218 if (symp->st_shndx != SHN_UNDEF && strcmp(name, strp) == 0) { 1219 *sym = (c_linker_sym_t) symp; 1220 return 0; 1221 } 1222 } 1223 return ENOENT; 1224 } 1225 1226 static int 1227 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, 1228 linker_symval_t *symval) 1229 { 1230 elf_file_t ef; 1231 const Elf_Sym *es; 1232 caddr_t val; 1233 1234 ef = (elf_file_t) lf; 1235 es = (const Elf_Sym*) sym; 1236 val = (caddr_t)es->st_value; 1237 if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) { 1238 symval->name = ef->ddbstrtab + es->st_name; 1239 val = (caddr_t)es->st_value; 1240 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC) 1241 val = ((caddr_t (*)(void))val)(); 1242 symval->value = val; 1243 symval->size = es->st_size; 1244 return 0; 1245 } 1246 return ENOENT; 1247 } 1248 1249 static int 1250 link_elf_search_symbol(linker_file_t lf, caddr_t value, 1251 c_linker_sym_t *sym, long *diffp) 1252 { 1253 elf_file_t ef = (elf_file_t) lf; 1254 u_long off = (uintptr_t) (void *) value; 1255 u_long diff = off; 1256 u_long st_value; 1257 const Elf_Sym *es; 1258 const Elf_Sym *best = NULL; 1259 int i; 1260 1261 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) { 1262 if (es->st_name == 0) 1263 continue; 1264 st_value = es->st_value; 1265 if (off >= st_value) { 1266 if (off - st_value < diff) { 1267 diff = off - st_value; 1268 best = es; 1269 if (diff == 0) 1270 break; 1271 } else if (off - st_value == diff) { 1272 best = es; 1273 } 1274 } 1275 } 1276 if (best == NULL) 1277 *diffp = off; 1278 else 1279 *diffp = diff; 1280 *sym = (c_linker_sym_t) best; 1281 1282 return 0; 1283 } 1284 1285 /* 1286 * Look up a linker set on an ELF system. 1287 */ 1288 static int 1289 link_elf_lookup_set(linker_file_t lf, const char *name, 1290 void ***startp, void ***stopp, int *countp) 1291 { 1292 elf_file_t ef = (elf_file_t)lf; 1293 void **start, **stop; 1294 int i, count; 1295 1296 /* Relative to section number */ 1297 for (i = 0; i < ef->nprogtab; i++) { 1298 if ((strncmp(ef->progtab[i].name, "set_", 4) == 0) && 1299 strcmp(ef->progtab[i].name + 4, name) == 0) { 1300 start = (void **)ef->progtab[i].addr; 1301 stop = (void **)((char *)ef->progtab[i].addr + 1302 ef->progtab[i].size); 1303 count = stop - start; 1304 if (startp) 1305 *startp = start; 1306 if (stopp) 1307 *stopp = stop; 1308 if (countp) 1309 *countp = count; 1310 return (0); 1311 } 1312 } 1313 return (ESRCH); 1314 } 1315 1316 static int 1317 link_elf_each_function_name(linker_file_t file, 1318 int (*callback)(const char *, void *), void *opaque) 1319 { 1320 elf_file_t ef = (elf_file_t)file; 1321 const Elf_Sym *symp; 1322 int i, error; 1323 1324 /* Exhaustive search */ 1325 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1326 if (symp->st_value != 0 && 1327 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1328 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) { 1329 error = callback(ef->ddbstrtab + symp->st_name, opaque); 1330 if (error) 1331 return (error); 1332 } 1333 } 1334 return (0); 1335 } 1336 1337 static int 1338 link_elf_each_function_nameval(linker_file_t file, 1339 linker_function_nameval_callback_t callback, void *opaque) 1340 { 1341 linker_symval_t symval; 1342 elf_file_t ef = (elf_file_t)file; 1343 const Elf_Sym* symp; 1344 int i, error; 1345 1346 /* Exhaustive search */ 1347 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1348 if (symp->st_value != 0 && 1349 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1350 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) { 1351 error = link_elf_symbol_values(file, 1352 (c_linker_sym_t)symp, &symval); 1353 if (error) 1354 return (error); 1355 error = callback(file, i, &symval, opaque); 1356 if (error) 1357 return (error); 1358 } 1359 } 1360 return (0); 1361 } 1362 1363 static void 1364 elf_obj_cleanup_globals_cache(elf_file_t ef) 1365 { 1366 Elf_Sym *sym; 1367 Elf_Size i; 1368 1369 for (i = 0; i < ef->ddbsymcnt; i++) { 1370 sym = ef->ddbsymtab + i; 1371 if (sym->st_shndx == SHN_FBSD_CACHED) { 1372 sym->st_shndx = SHN_UNDEF; 1373 sym->st_value = 0; 1374 } 1375 } 1376 } 1377 1378 /* 1379 * Symbol lookup function that can be used when the symbol index is known (ie 1380 * in relocations). It uses the symbol index instead of doing a fully fledged 1381 * hash table based lookup when such is valid. For example for local symbols. 1382 * This is not only more efficient, it's also more correct. It's not always 1383 * the case that the symbol can be found through the hash table. 1384 */ 1385 static int 1386 elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res) 1387 { 1388 elf_file_t ef = (elf_file_t)lf; 1389 Elf_Sym *sym; 1390 const char *symbol; 1391 Elf_Addr res1; 1392 1393 /* Don't even try to lookup the symbol if the index is bogus. */ 1394 if (symidx >= ef->ddbsymcnt) { 1395 *res = 0; 1396 return (EINVAL); 1397 } 1398 1399 sym = ef->ddbsymtab + symidx; 1400 1401 /* Quick answer if there is a definition included. */ 1402 if (sym->st_shndx != SHN_UNDEF) { 1403 res1 = (Elf_Addr)sym->st_value; 1404 if (ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC) 1405 res1 = ((Elf_Addr (*)(void))res1)(); 1406 *res = res1; 1407 return (0); 1408 } 1409 1410 /* If we get here, then it is undefined and needs a lookup. */ 1411 switch (ELF_ST_BIND(sym->st_info)) { 1412 case STB_LOCAL: 1413 /* Local, but undefined? huh? */ 1414 *res = 0; 1415 return (EINVAL); 1416 1417 case STB_GLOBAL: 1418 case STB_WEAK: 1419 /* Relative to Data or Function name */ 1420 symbol = ef->ddbstrtab + sym->st_name; 1421 1422 /* Force a lookup failure if the symbol name is bogus. */ 1423 if (*symbol == 0) { 1424 *res = 0; 1425 return (EINVAL); 1426 } 1427 res1 = (Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps); 1428 1429 /* 1430 * Cache global lookups during module relocation. The failure 1431 * case is particularly expensive for callers, who must scan 1432 * through the entire globals table doing strcmp(). Cache to 1433 * avoid doing such work repeatedly. 1434 * 1435 * After relocation is complete, undefined globals will be 1436 * restored to SHN_UNDEF in elf_obj_cleanup_globals_cache(), 1437 * above. 1438 */ 1439 if (res1 != 0) { 1440 sym->st_shndx = SHN_FBSD_CACHED; 1441 sym->st_value = res1; 1442 *res = res1; 1443 return (0); 1444 } else if (ELF_ST_BIND(sym->st_info) == STB_WEAK) { 1445 sym->st_value = 0; 1446 *res = 0; 1447 return (0); 1448 } 1449 return (EINVAL); 1450 1451 default: 1452 return (EINVAL); 1453 } 1454 } 1455 1456 static void 1457 link_elf_fix_link_set(elf_file_t ef) 1458 { 1459 static const char startn[] = "__start_"; 1460 static const char stopn[] = "__stop_"; 1461 Elf_Sym *sym; 1462 const char *sym_name, *linkset_name; 1463 Elf_Addr startp, stopp; 1464 Elf_Size symidx; 1465 int start, i; 1466 1467 startp = stopp = 0; 1468 for (symidx = 1 /* zero entry is special */; 1469 symidx < ef->ddbsymcnt; symidx++) { 1470 sym = ef->ddbsymtab + symidx; 1471 if (sym->st_shndx != SHN_UNDEF) 1472 continue; 1473 1474 sym_name = ef->ddbstrtab + sym->st_name; 1475 if (strncmp(sym_name, startn, sizeof(startn) - 1) == 0) { 1476 start = 1; 1477 linkset_name = sym_name + sizeof(startn) - 1; 1478 } 1479 else if (strncmp(sym_name, stopn, sizeof(stopn) - 1) == 0) { 1480 start = 0; 1481 linkset_name = sym_name + sizeof(stopn) - 1; 1482 } 1483 else 1484 continue; 1485 1486 for (i = 0; i < ef->nprogtab; i++) { 1487 if (strcmp(ef->progtab[i].name, linkset_name) == 0) { 1488 startp = (Elf_Addr)ef->progtab[i].addr; 1489 stopp = (Elf_Addr)(startp + ef->progtab[i].size); 1490 break; 1491 } 1492 } 1493 if (i == ef->nprogtab) 1494 continue; 1495 1496 sym->st_value = start ? startp : stopp; 1497 sym->st_shndx = i; 1498 } 1499 } 1500 1501 static int 1502 link_elf_reloc_local(linker_file_t lf, bool ifuncs) 1503 { 1504 elf_file_t ef = (elf_file_t)lf; 1505 const Elf_Rel *rellim; 1506 const Elf_Rel *rel; 1507 const Elf_Rela *relalim; 1508 const Elf_Rela *rela; 1509 const Elf_Sym *sym; 1510 Elf_Addr base; 1511 int i; 1512 Elf_Size symidx; 1513 1514 link_elf_fix_link_set(ef); 1515 1516 /* Perform relocations without addend if there are any: */ 1517 for (i = 0; i < ef->nreltab; i++) { 1518 rel = ef->reltab[i].rel; 1519 if (rel == NULL) { 1520 link_elf_error(ef->lf.filename, "lost a reltab"); 1521 return (ENOEXEC); 1522 } 1523 rellim = rel + ef->reltab[i].nrel; 1524 base = findbase(ef, ef->reltab[i].sec); 1525 if (base == 0) { 1526 link_elf_error(ef->lf.filename, "lost base for reltab"); 1527 return (ENOEXEC); 1528 } 1529 for ( ; rel < rellim; rel++) { 1530 symidx = ELF_R_SYM(rel->r_info); 1531 if (symidx >= ef->ddbsymcnt) 1532 continue; 1533 sym = ef->ddbsymtab + symidx; 1534 /* Only do local relocs */ 1535 if (ELF_ST_BIND(sym->st_info) != STB_LOCAL) 1536 continue; 1537 if ((ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC || 1538 elf_is_ifunc_reloc(rel->r_info)) == ifuncs) 1539 elf_reloc_local(lf, base, rel, ELF_RELOC_REL, 1540 elf_obj_lookup); 1541 } 1542 } 1543 1544 /* Perform relocations with addend if there are any: */ 1545 for (i = 0; i < ef->nrelatab; i++) { 1546 rela = ef->relatab[i].rela; 1547 if (rela == NULL) { 1548 link_elf_error(ef->lf.filename, "lost a relatab!"); 1549 return (ENOEXEC); 1550 } 1551 relalim = rela + ef->relatab[i].nrela; 1552 base = findbase(ef, ef->relatab[i].sec); 1553 if (base == 0) { 1554 link_elf_error(ef->lf.filename, "lost base for reltab"); 1555 return (ENOEXEC); 1556 } 1557 for ( ; rela < relalim; rela++) { 1558 symidx = ELF_R_SYM(rela->r_info); 1559 if (symidx >= ef->ddbsymcnt) 1560 continue; 1561 sym = ef->ddbsymtab + symidx; 1562 /* Only do local relocs */ 1563 if (ELF_ST_BIND(sym->st_info) != STB_LOCAL) 1564 continue; 1565 if ((ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC || 1566 elf_is_ifunc_reloc(rela->r_info)) == ifuncs) 1567 elf_reloc_local(lf, base, rela, ELF_RELOC_RELA, 1568 elf_obj_lookup); 1569 } 1570 } 1571 return (0); 1572 } 1573 1574 static long 1575 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab) 1576 { 1577 elf_file_t ef = (elf_file_t)lf; 1578 1579 *symtab = ef->ddbsymtab; 1580 1581 if (*symtab == NULL) 1582 return (0); 1583 1584 return (ef->ddbsymcnt); 1585 } 1586 1587 static long 1588 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab) 1589 { 1590 elf_file_t ef = (elf_file_t)lf; 1591 1592 *strtab = ef->ddbstrtab; 1593 1594 if (*strtab == NULL) 1595 return (0); 1596 1597 return (ef->ddbstrcnt); 1598 }
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