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("$FreeBSD$"); 32 33 #include "opt_ddb.h" 34 35 #include <sys/param.h> 36 #include <sys/systm.h> 37 #include <sys/fcntl.h> 38 #include <sys/kernel.h> 39 #include <sys/lock.h> 40 #include <sys/malloc.h> 41 #include <sys/linker.h> 42 #include <sys/mutex.h> 43 #include <sys/mount.h> 44 #include <sys/namei.h> 45 #include <sys/proc.h> 46 #include <sys/rwlock.h> 47 #include <sys/vnode.h> 48 49 #include <machine/elf.h> 50 51 #include <net/vnet.h> 52 53 #include <security/mac/mac_framework.h> 54 55 #include <vm/vm.h> 56 #include <vm/vm_param.h> 57 #include <vm/pmap.h> 58 #include <vm/vm_extern.h> 59 #include <vm/vm_kern.h> 60 #include <vm/vm_map.h> 61 #include <vm/vm_object.h> 62 #include <vm/vm_page.h> 63 #include <vm/vm_pager.h> 64 65 #include <sys/link_elf.h> 66 67 #ifdef DDB_CTF 68 #include <contrib/zlib/zlib.h> 69 #endif 70 71 #include "linker_if.h" 72 73 typedef struct { 74 void *addr; 75 Elf_Off size; 76 int flags; /* Section flags. */ 77 int sec; /* Original section number. */ 78 char *name; 79 } Elf_progent; 80 81 typedef struct { 82 Elf_Rel *rel; 83 int nrel; 84 int sec; 85 } Elf_relent; 86 87 typedef struct { 88 Elf_Rela *rela; 89 int nrela; 90 int sec; 91 } Elf_relaent; 92 93 typedef struct elf_file { 94 struct linker_file lf; /* Common fields */ 95 96 int preloaded; 97 caddr_t address; /* Relocation address */ 98 vm_object_t object; /* VM object to hold file pages */ 99 Elf_Shdr *e_shdr; 100 101 Elf_progent *progtab; 102 u_int nprogtab; 103 104 Elf_relaent *relatab; 105 u_int nrelatab; 106 107 Elf_relent *reltab; 108 int nreltab; 109 110 Elf_Sym *ddbsymtab; /* The symbol table we are using */ 111 long ddbsymcnt; /* Number of symbols */ 112 caddr_t ddbstrtab; /* String table */ 113 long ddbstrcnt; /* number of bytes in string table */ 114 115 caddr_t shstrtab; /* Section name string table */ 116 long shstrcnt; /* number of bytes in string table */ 117 118 caddr_t ctftab; /* CTF table */ 119 long ctfcnt; /* number of bytes in CTF table */ 120 caddr_t ctfoff; /* CTF offset table */ 121 caddr_t typoff; /* Type offset table */ 122 long typlen; /* Number of type entries. */ 123 124 } *elf_file_t; 125 126 #include <kern/kern_ctf.c> 127 128 static int link_elf_link_preload(linker_class_t cls, 129 const char *, linker_file_t *); 130 static int link_elf_link_preload_finish(linker_file_t); 131 static int link_elf_load_file(linker_class_t, const char *, linker_file_t *); 132 static int link_elf_lookup_symbol(linker_file_t, const char *, 133 c_linker_sym_t *); 134 static int link_elf_symbol_values(linker_file_t, c_linker_sym_t, 135 linker_symval_t *); 136 static int link_elf_search_symbol(linker_file_t, caddr_t value, 137 c_linker_sym_t *sym, long *diffp); 138 139 static void link_elf_unload_file(linker_file_t); 140 static int link_elf_lookup_set(linker_file_t, const char *, 141 void ***, void ***, int *); 142 static int link_elf_each_function_name(linker_file_t, 143 int (*)(const char *, void *), void *); 144 static int link_elf_each_function_nameval(linker_file_t, 145 linker_function_nameval_callback_t, 146 void *); 147 static int link_elf_reloc_local(linker_file_t, bool); 148 static long link_elf_symtab_get(linker_file_t, const Elf_Sym **); 149 static long link_elf_strtab_get(linker_file_t, caddr_t *); 150 151 static int elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps, 152 Elf_Addr *); 153 154 static kobj_method_t link_elf_methods[] = { 155 KOBJMETHOD(linker_lookup_symbol, link_elf_lookup_symbol), 156 KOBJMETHOD(linker_symbol_values, link_elf_symbol_values), 157 KOBJMETHOD(linker_search_symbol, link_elf_search_symbol), 158 KOBJMETHOD(linker_unload, link_elf_unload_file), 159 KOBJMETHOD(linker_load_file, link_elf_load_file), 160 KOBJMETHOD(linker_link_preload, link_elf_link_preload), 161 KOBJMETHOD(linker_link_preload_finish, link_elf_link_preload_finish), 162 KOBJMETHOD(linker_lookup_set, link_elf_lookup_set), 163 KOBJMETHOD(linker_each_function_name, link_elf_each_function_name), 164 KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval), 165 KOBJMETHOD(linker_ctf_get, link_elf_ctf_get), 166 KOBJMETHOD(linker_symtab_get, link_elf_symtab_get), 167 KOBJMETHOD(linker_strtab_get, link_elf_strtab_get), 168 KOBJMETHOD_END 169 }; 170 171 static struct linker_class link_elf_class = { 172 #if ELF_TARG_CLASS == ELFCLASS32 173 "elf32_obj", 174 #else 175 "elf64_obj", 176 #endif 177 link_elf_methods, sizeof(struct elf_file) 178 }; 179 180 static int relocate_file(elf_file_t ef); 181 static void elf_obj_cleanup_globals_cache(elf_file_t); 182 183 static void 184 link_elf_error(const char *filename, const char *s) 185 { 186 if (filename == NULL) 187 printf("kldload: %s\n", s); 188 else 189 printf("kldload: %s: %s\n", filename, s); 190 } 191 192 static void 193 link_elf_init(void *arg) 194 { 195 196 linker_add_class(&link_elf_class); 197 } 198 SYSINIT(link_elf_obj, SI_SUB_KLD, SI_ORDER_SECOND, link_elf_init, NULL); 199 200 static void 201 link_elf_protect_range(elf_file_t ef, vm_offset_t start, vm_offset_t end, 202 vm_prot_t prot) 203 { 204 int error __unused; 205 206 KASSERT(start <= end && start >= (vm_offset_t)ef->address && 207 end <= round_page((vm_offset_t)ef->address + ef->lf.size), 208 ("link_elf_protect_range: invalid range %#jx-%#jx", 209 (uintmax_t)start, (uintmax_t)end)); 210 211 if (start == end) 212 return; 213 if (ef->preloaded) { 214 #ifdef __amd64__ 215 error = pmap_change_prot(start, end - start, prot); 216 KASSERT(error == 0, 217 ("link_elf_protect_range: pmap_change_prot() returned %d", 218 error)); 219 #endif 220 return; 221 } 222 error = vm_map_protect(kernel_map, start, end, prot, 0, 223 VM_MAP_PROTECT_SET_PROT); 224 KASSERT(error == KERN_SUCCESS, 225 ("link_elf_protect_range: vm_map_protect() returned %d", error)); 226 } 227 228 /* 229 * Restrict permissions on linker file memory based on section flags. 230 * Sections need not be page-aligned, so overlap within a page is possible. 231 */ 232 static void 233 link_elf_protect(elf_file_t ef) 234 { 235 vm_offset_t end, segend, segstart, start; 236 vm_prot_t gapprot, prot, segprot; 237 int i; 238 239 /* 240 * If the file was preloaded, the last page may contain other preloaded 241 * data which may need to be writeable. ELF files are always 242 * page-aligned, but other preloaded data, such as entropy or CPU 243 * microcode may be loaded with a smaller alignment. 244 */ 245 gapprot = ef->preloaded ? VM_PROT_RW : VM_PROT_READ; 246 247 start = end = (vm_offset_t)ef->address; 248 prot = VM_PROT_READ; 249 for (i = 0; i < ef->nprogtab; i++) { 250 /* 251 * VNET and DPCPU sections have their memory allocated by their 252 * respective subsystems. 253 */ 254 if (ef->progtab[i].name != NULL && ( 255 #ifdef VIMAGE 256 strcmp(ef->progtab[i].name, VNET_SETNAME) == 0 || 257 #endif 258 strcmp(ef->progtab[i].name, DPCPU_SETNAME) == 0)) 259 continue; 260 261 segstart = trunc_page((vm_offset_t)ef->progtab[i].addr); 262 segend = round_page((vm_offset_t)ef->progtab[i].addr + 263 ef->progtab[i].size); 264 segprot = VM_PROT_READ; 265 if ((ef->progtab[i].flags & SHF_WRITE) != 0) 266 segprot |= VM_PROT_WRITE; 267 if ((ef->progtab[i].flags & SHF_EXECINSTR) != 0) 268 segprot |= VM_PROT_EXECUTE; 269 270 if (end <= segstart) { 271 /* 272 * Case 1: there is no overlap between the previous 273 * segment and this one. Apply protections to the 274 * previous segment, and protect the gap between the 275 * previous and current segments, if any. 276 */ 277 link_elf_protect_range(ef, start, end, prot); 278 link_elf_protect_range(ef, end, segstart, gapprot); 279 280 start = segstart; 281 end = segend; 282 prot = segprot; 283 } else if (start < segstart && end == segend) { 284 /* 285 * Case 2: the current segment is a subrange of the 286 * previous segment. Apply protections to the 287 * non-overlapping portion of the previous segment. 288 */ 289 link_elf_protect_range(ef, start, segstart, prot); 290 291 start = segstart; 292 prot |= segprot; 293 } else if (end < segend) { 294 /* 295 * Case 3: there is partial overlap between the previous 296 * and current segments. Apply protections to the 297 * non-overlapping portion of the previous segment, and 298 * then the overlap, which must use the union of the two 299 * segments' protections. 300 */ 301 link_elf_protect_range(ef, start, segstart, prot); 302 link_elf_protect_range(ef, segstart, end, 303 prot | segprot); 304 start = end; 305 end = segend; 306 prot = segprot; 307 } else { 308 /* 309 * Case 4: the two segments reside in the same page. 310 */ 311 prot |= segprot; 312 } 313 } 314 315 /* 316 * Fix up the last unprotected segment and trailing data. 317 */ 318 link_elf_protect_range(ef, start, end, prot); 319 link_elf_protect_range(ef, end, 320 round_page((vm_offset_t)ef->address + ef->lf.size), gapprot); 321 } 322 323 static int 324 link_elf_link_preload(linker_class_t cls, const char *filename, 325 linker_file_t *result) 326 { 327 Elf_Ehdr *hdr; 328 Elf_Shdr *shdr; 329 Elf_Sym *es; 330 void *modptr, *baseptr, *sizeptr; 331 char *type; 332 elf_file_t ef; 333 linker_file_t lf; 334 Elf_Addr off; 335 int error, i, j, pb, ra, rl, shstrindex, symstrindex, symtabindex; 336 337 /* Look to see if we have the file preloaded */ 338 modptr = preload_search_by_name(filename); 339 if (modptr == NULL) 340 return ENOENT; 341 342 type = (char *)preload_search_info(modptr, MODINFO_TYPE); 343 baseptr = preload_search_info(modptr, MODINFO_ADDR); 344 sizeptr = preload_search_info(modptr, MODINFO_SIZE); 345 hdr = (Elf_Ehdr *)preload_search_info(modptr, MODINFO_METADATA | 346 MODINFOMD_ELFHDR); 347 shdr = (Elf_Shdr *)preload_search_info(modptr, MODINFO_METADATA | 348 MODINFOMD_SHDR); 349 if (type == NULL || (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) 350 " obj module") != 0 && 351 strcmp(type, "elf obj module") != 0)) { 352 return (EFTYPE); 353 } 354 if (baseptr == NULL || sizeptr == NULL || hdr == NULL || 355 shdr == NULL) 356 return (EINVAL); 357 358 lf = linker_make_file(filename, &link_elf_class); 359 if (lf == NULL) 360 return (ENOMEM); 361 362 ef = (elf_file_t)lf; 363 ef->preloaded = 1; 364 ef->address = *(caddr_t *)baseptr; 365 lf->address = *(caddr_t *)baseptr; 366 lf->size = *(size_t *)sizeptr; 367 368 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS || 369 hdr->e_ident[EI_DATA] != ELF_TARG_DATA || 370 hdr->e_ident[EI_VERSION] != EV_CURRENT || 371 hdr->e_version != EV_CURRENT || 372 hdr->e_type != ET_REL || 373 hdr->e_machine != ELF_TARG_MACH) { 374 error = EFTYPE; 375 goto out; 376 } 377 ef->e_shdr = shdr; 378 379 /* Scan the section header for information and table sizing. */ 380 symtabindex = -1; 381 symstrindex = -1; 382 for (i = 0; i < hdr->e_shnum; i++) { 383 switch (shdr[i].sh_type) { 384 case SHT_PROGBITS: 385 case SHT_NOBITS: 386 #ifdef __amd64__ 387 case SHT_X86_64_UNWIND: 388 #endif 389 /* Ignore sections not loaded by the loader. */ 390 if (shdr[i].sh_addr == 0) 391 break; 392 ef->nprogtab++; 393 break; 394 case SHT_SYMTAB: 395 symtabindex = i; 396 symstrindex = shdr[i].sh_link; 397 break; 398 case SHT_REL: 399 /* 400 * Ignore relocation tables for sections not 401 * loaded by the loader. 402 */ 403 if (shdr[shdr[i].sh_info].sh_addr == 0) 404 break; 405 ef->nreltab++; 406 break; 407 case SHT_RELA: 408 if (shdr[shdr[i].sh_info].sh_addr == 0) 409 break; 410 ef->nrelatab++; 411 break; 412 } 413 } 414 415 shstrindex = hdr->e_shstrndx; 416 if (ef->nprogtab == 0 || symstrindex < 0 || 417 symstrindex >= hdr->e_shnum || 418 shdr[symstrindex].sh_type != SHT_STRTAB || shstrindex == 0 || 419 shstrindex >= hdr->e_shnum || 420 shdr[shstrindex].sh_type != SHT_STRTAB) { 421 printf("%s: bad/missing section headers\n", filename); 422 error = ENOEXEC; 423 goto out; 424 } 425 426 /* Allocate space for tracking the load chunks */ 427 if (ef->nprogtab != 0) 428 ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab), 429 M_LINKER, M_WAITOK | M_ZERO); 430 if (ef->nreltab != 0) 431 ef->reltab = malloc(ef->nreltab * sizeof(*ef->reltab), 432 M_LINKER, M_WAITOK | M_ZERO); 433 if (ef->nrelatab != 0) 434 ef->relatab = malloc(ef->nrelatab * sizeof(*ef->relatab), 435 M_LINKER, M_WAITOK | M_ZERO); 436 if ((ef->nprogtab != 0 && ef->progtab == NULL) || 437 (ef->nreltab != 0 && ef->reltab == NULL) || 438 (ef->nrelatab != 0 && ef->relatab == NULL)) { 439 error = ENOMEM; 440 goto out; 441 } 442 443 /* XXX, relocate the sh_addr fields saved by the loader. */ 444 off = 0; 445 for (i = 0; i < hdr->e_shnum; i++) { 446 if (shdr[i].sh_addr != 0 && (off == 0 || shdr[i].sh_addr < off)) 447 off = shdr[i].sh_addr; 448 } 449 for (i = 0; i < hdr->e_shnum; i++) { 450 if (shdr[i].sh_addr != 0) 451 shdr[i].sh_addr = shdr[i].sh_addr - off + 452 (Elf_Addr)ef->address; 453 } 454 455 ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym); 456 ef->ddbsymtab = (Elf_Sym *)shdr[symtabindex].sh_addr; 457 ef->ddbstrcnt = shdr[symstrindex].sh_size; 458 ef->ddbstrtab = (char *)shdr[symstrindex].sh_addr; 459 ef->shstrcnt = shdr[shstrindex].sh_size; 460 ef->shstrtab = (char *)shdr[shstrindex].sh_addr; 461 462 /* Now fill out progtab and the relocation tables. */ 463 pb = 0; 464 rl = 0; 465 ra = 0; 466 for (i = 0; i < hdr->e_shnum; i++) { 467 switch (shdr[i].sh_type) { 468 case SHT_PROGBITS: 469 case SHT_NOBITS: 470 #ifdef __amd64__ 471 case SHT_X86_64_UNWIND: 472 #endif 473 if (shdr[i].sh_addr == 0) 474 break; 475 ef->progtab[pb].addr = (void *)shdr[i].sh_addr; 476 if (shdr[i].sh_type == SHT_PROGBITS) 477 ef->progtab[pb].name = "<<PROGBITS>>"; 478 #ifdef __amd64__ 479 else if (shdr[i].sh_type == SHT_X86_64_UNWIND) 480 ef->progtab[pb].name = "<<UNWIND>>"; 481 #endif 482 else 483 ef->progtab[pb].name = "<<NOBITS>>"; 484 ef->progtab[pb].size = shdr[i].sh_size; 485 ef->progtab[pb].flags = shdr[i].sh_flags; 486 ef->progtab[pb].sec = i; 487 if (ef->shstrtab && shdr[i].sh_name != 0) 488 ef->progtab[pb].name = 489 ef->shstrtab + shdr[i].sh_name; 490 if (ef->progtab[pb].name != NULL && 491 !strcmp(ef->progtab[pb].name, DPCPU_SETNAME)) { 492 void *dpcpu; 493 494 dpcpu = dpcpu_alloc(shdr[i].sh_size); 495 if (dpcpu == NULL) { 496 printf("%s: pcpu module space is out " 497 "of space; cannot allocate %#jx " 498 "for %s\n", __func__, 499 (uintmax_t)shdr[i].sh_size, 500 filename); 501 error = ENOSPC; 502 goto out; 503 } 504 memcpy(dpcpu, ef->progtab[pb].addr, 505 ef->progtab[pb].size); 506 dpcpu_copy(dpcpu, shdr[i].sh_size); 507 ef->progtab[pb].addr = dpcpu; 508 #ifdef VIMAGE 509 } else if (ef->progtab[pb].name != NULL && 510 !strcmp(ef->progtab[pb].name, VNET_SETNAME)) { 511 void *vnet_data; 512 513 vnet_data = vnet_data_alloc(shdr[i].sh_size); 514 if (vnet_data == NULL) { 515 printf("%s: vnet module space is out " 516 "of space; cannot allocate %#jx " 517 "for %s\n", __func__, 518 (uintmax_t)shdr[i].sh_size, 519 filename); 520 error = ENOSPC; 521 goto out; 522 } 523 memcpy(vnet_data, ef->progtab[pb].addr, 524 ef->progtab[pb].size); 525 vnet_data_copy(vnet_data, shdr[i].sh_size); 526 ef->progtab[pb].addr = vnet_data; 527 #endif 528 } else if (ef->progtab[pb].name != NULL && 529 !strcmp(ef->progtab[pb].name, ".ctors")) { 530 lf->ctors_addr = ef->progtab[pb].addr; 531 lf->ctors_size = shdr[i].sh_size; 532 } 533 534 /* Update all symbol values with the offset. */ 535 for (j = 0; j < ef->ddbsymcnt; j++) { 536 es = &ef->ddbsymtab[j]; 537 if (es->st_shndx != i) 538 continue; 539 es->st_value += (Elf_Addr)ef->progtab[pb].addr; 540 } 541 pb++; 542 break; 543 case SHT_REL: 544 if (shdr[shdr[i].sh_info].sh_addr == 0) 545 break; 546 ef->reltab[rl].rel = (Elf_Rel *)shdr[i].sh_addr; 547 ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel); 548 ef->reltab[rl].sec = shdr[i].sh_info; 549 rl++; 550 break; 551 case SHT_RELA: 552 if (shdr[shdr[i].sh_info].sh_addr == 0) 553 break; 554 ef->relatab[ra].rela = (Elf_Rela *)shdr[i].sh_addr; 555 ef->relatab[ra].nrela = 556 shdr[i].sh_size / sizeof(Elf_Rela); 557 ef->relatab[ra].sec = shdr[i].sh_info; 558 ra++; 559 break; 560 } 561 } 562 if (pb != ef->nprogtab) { 563 printf("%s: lost progbits\n", filename); 564 error = ENOEXEC; 565 goto out; 566 } 567 if (rl != ef->nreltab) { 568 printf("%s: lost reltab\n", filename); 569 error = ENOEXEC; 570 goto out; 571 } 572 if (ra != ef->nrelatab) { 573 printf("%s: lost relatab\n", filename); 574 error = ENOEXEC; 575 goto out; 576 } 577 578 /* 579 * The file needs to be writeable and executable while applying 580 * relocations. Mapping protections are applied once relocation 581 * processing is complete. 582 */ 583 link_elf_protect_range(ef, (vm_offset_t)ef->address, 584 round_page((vm_offset_t)ef->address + ef->lf.size), VM_PROT_ALL); 585 586 /* Local intra-module relocations */ 587 error = link_elf_reloc_local(lf, false); 588 if (error != 0) 589 goto out; 590 *result = lf; 591 return (0); 592 593 out: 594 /* preload not done this way */ 595 linker_file_unload(lf, LINKER_UNLOAD_FORCE); 596 return (error); 597 } 598 599 static void 600 link_elf_invoke_ctors(caddr_t addr, size_t size) 601 { 602 void (**ctor)(void); 603 size_t i, cnt; 604 605 if (addr == NULL || size == 0) 606 return; 607 cnt = size / sizeof(*ctor); 608 ctor = (void *)addr; 609 for (i = 0; i < cnt; i++) { 610 if (ctor[i] != NULL) 611 (*ctor[i])(); 612 } 613 } 614 615 static int 616 link_elf_link_preload_finish(linker_file_t lf) 617 { 618 elf_file_t ef; 619 int error; 620 621 ef = (elf_file_t)lf; 622 error = relocate_file(ef); 623 if (error) 624 return (error); 625 626 /* Notify MD code that a module is being loaded. */ 627 error = elf_cpu_load_file(lf); 628 if (error) 629 return (error); 630 631 #if defined(__i386__) || defined(__amd64__) 632 /* Now ifuncs. */ 633 error = link_elf_reloc_local(lf, true); 634 if (error != 0) 635 return (error); 636 #endif 637 638 /* Apply protections now that relocation processing is complete. */ 639 link_elf_protect(ef); 640 641 link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size); 642 return (0); 643 } 644 645 static int 646 link_elf_load_file(linker_class_t cls, const char *filename, 647 linker_file_t *result) 648 { 649 struct nameidata *nd; 650 struct thread *td = curthread; /* XXX */ 651 Elf_Ehdr *hdr; 652 Elf_Shdr *shdr; 653 Elf_Sym *es; 654 int nbytes, i, j; 655 vm_offset_t mapbase; 656 size_t mapsize; 657 int error = 0; 658 ssize_t resid; 659 int flags; 660 elf_file_t ef; 661 linker_file_t lf; 662 int symtabindex; 663 int symstrindex; 664 int shstrindex; 665 int nsym; 666 int pb, rl, ra; 667 int alignmask; 668 669 shdr = NULL; 670 lf = NULL; 671 mapsize = 0; 672 hdr = NULL; 673 674 nd = malloc(sizeof(struct nameidata), M_TEMP, M_WAITOK); 675 NDINIT(nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td); 676 flags = FREAD; 677 error = vn_open(nd, &flags, 0, NULL); 678 if (error) { 679 free(nd, M_TEMP); 680 return error; 681 } 682 NDFREE(nd, NDF_ONLY_PNBUF); 683 if (nd->ni_vp->v_type != VREG) { 684 error = ENOEXEC; 685 goto out; 686 } 687 #ifdef MAC 688 error = mac_kld_check_load(td->td_ucred, nd->ni_vp); 689 if (error) { 690 goto out; 691 } 692 #endif 693 694 /* Read the elf header from the file. */ 695 hdr = malloc(sizeof(*hdr), M_LINKER, M_WAITOK); 696 error = vn_rdwr(UIO_READ, nd->ni_vp, (void *)hdr, sizeof(*hdr), 0, 697 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 698 &resid, td); 699 if (error) 700 goto out; 701 if (resid != 0){ 702 error = ENOEXEC; 703 goto out; 704 } 705 706 if (!IS_ELF(*hdr)) { 707 error = ENOEXEC; 708 goto out; 709 } 710 711 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS 712 || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) { 713 link_elf_error(filename, "Unsupported file layout"); 714 error = ENOEXEC; 715 goto out; 716 } 717 if (hdr->e_ident[EI_VERSION] != EV_CURRENT 718 || hdr->e_version != EV_CURRENT) { 719 link_elf_error(filename, "Unsupported file version"); 720 error = ENOEXEC; 721 goto out; 722 } 723 if (hdr->e_type != ET_REL) { 724 error = ENOSYS; 725 goto out; 726 } 727 if (hdr->e_machine != ELF_TARG_MACH) { 728 link_elf_error(filename, "Unsupported machine"); 729 error = ENOEXEC; 730 goto out; 731 } 732 733 lf = linker_make_file(filename, &link_elf_class); 734 if (!lf) { 735 error = ENOMEM; 736 goto out; 737 } 738 ef = (elf_file_t) lf; 739 ef->nprogtab = 0; 740 ef->e_shdr = 0; 741 ef->nreltab = 0; 742 ef->nrelatab = 0; 743 744 /* Allocate and read in the section header */ 745 nbytes = hdr->e_shnum * hdr->e_shentsize; 746 if (nbytes == 0 || hdr->e_shoff == 0 || 747 hdr->e_shentsize != sizeof(Elf_Shdr)) { 748 error = ENOEXEC; 749 goto out; 750 } 751 shdr = malloc(nbytes, M_LINKER, M_WAITOK); 752 ef->e_shdr = shdr; 753 error = vn_rdwr(UIO_READ, nd->ni_vp, (caddr_t)shdr, nbytes, 754 hdr->e_shoff, UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, 755 NOCRED, &resid, td); 756 if (error) 757 goto out; 758 if (resid) { 759 error = ENOEXEC; 760 goto out; 761 } 762 763 /* Scan the section header for information and table sizing. */ 764 nsym = 0; 765 symtabindex = -1; 766 symstrindex = -1; 767 for (i = 0; i < hdr->e_shnum; i++) { 768 if (shdr[i].sh_size == 0) 769 continue; 770 switch (shdr[i].sh_type) { 771 case SHT_PROGBITS: 772 case SHT_NOBITS: 773 #ifdef __amd64__ 774 case SHT_X86_64_UNWIND: 775 #endif 776 if ((shdr[i].sh_flags & SHF_ALLOC) == 0) 777 break; 778 ef->nprogtab++; 779 break; 780 case SHT_SYMTAB: 781 nsym++; 782 symtabindex = i; 783 symstrindex = shdr[i].sh_link; 784 break; 785 case SHT_REL: 786 /* 787 * Ignore relocation tables for unallocated 788 * sections. 789 */ 790 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0) 791 break; 792 ef->nreltab++; 793 break; 794 case SHT_RELA: 795 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0) 796 break; 797 ef->nrelatab++; 798 break; 799 case SHT_STRTAB: 800 break; 801 } 802 } 803 if (ef->nprogtab == 0) { 804 link_elf_error(filename, "file has no contents"); 805 error = ENOEXEC; 806 goto out; 807 } 808 if (nsym != 1) { 809 /* Only allow one symbol table for now */ 810 link_elf_error(filename, 811 "file must have exactly one symbol table"); 812 error = ENOEXEC; 813 goto out; 814 } 815 if (symstrindex < 0 || symstrindex > hdr->e_shnum || 816 shdr[symstrindex].sh_type != SHT_STRTAB) { 817 link_elf_error(filename, "file has invalid symbol strings"); 818 error = ENOEXEC; 819 goto out; 820 } 821 822 /* Allocate space for tracking the load chunks */ 823 if (ef->nprogtab != 0) 824 ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab), 825 M_LINKER, M_WAITOK | M_ZERO); 826 if (ef->nreltab != 0) 827 ef->reltab = malloc(ef->nreltab * sizeof(*ef->reltab), 828 M_LINKER, M_WAITOK | M_ZERO); 829 if (ef->nrelatab != 0) 830 ef->relatab = malloc(ef->nrelatab * sizeof(*ef->relatab), 831 M_LINKER, M_WAITOK | M_ZERO); 832 833 if (symtabindex == -1) { 834 link_elf_error(filename, "lost symbol table index"); 835 error = ENOEXEC; 836 goto out; 837 } 838 /* Allocate space for and load the symbol table */ 839 ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym); 840 ef->ddbsymtab = malloc(shdr[symtabindex].sh_size, M_LINKER, M_WAITOK); 841 error = vn_rdwr(UIO_READ, nd->ni_vp, (void *)ef->ddbsymtab, 842 shdr[symtabindex].sh_size, shdr[symtabindex].sh_offset, 843 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 844 &resid, td); 845 if (error) 846 goto out; 847 if (resid != 0){ 848 error = EINVAL; 849 goto out; 850 } 851 852 /* Allocate space for and load the symbol strings */ 853 ef->ddbstrcnt = shdr[symstrindex].sh_size; 854 ef->ddbstrtab = malloc(shdr[symstrindex].sh_size, M_LINKER, M_WAITOK); 855 error = vn_rdwr(UIO_READ, nd->ni_vp, ef->ddbstrtab, 856 shdr[symstrindex].sh_size, shdr[symstrindex].sh_offset, 857 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 858 &resid, td); 859 if (error) 860 goto out; 861 if (resid != 0){ 862 error = EINVAL; 863 goto out; 864 } 865 866 /* Do we have a string table for the section names? */ 867 shstrindex = -1; 868 if (hdr->e_shstrndx != 0 && 869 shdr[hdr->e_shstrndx].sh_type == SHT_STRTAB) { 870 shstrindex = hdr->e_shstrndx; 871 ef->shstrcnt = shdr[shstrindex].sh_size; 872 ef->shstrtab = malloc(shdr[shstrindex].sh_size, M_LINKER, 873 M_WAITOK); 874 error = vn_rdwr(UIO_READ, nd->ni_vp, ef->shstrtab, 875 shdr[shstrindex].sh_size, shdr[shstrindex].sh_offset, 876 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 877 &resid, td); 878 if (error) 879 goto out; 880 if (resid != 0){ 881 error = EINVAL; 882 goto out; 883 } 884 } 885 886 /* Size up code/data(progbits) and bss(nobits). */ 887 alignmask = 0; 888 for (i = 0; i < hdr->e_shnum; i++) { 889 if (shdr[i].sh_size == 0) 890 continue; 891 switch (shdr[i].sh_type) { 892 case SHT_PROGBITS: 893 case SHT_NOBITS: 894 #ifdef __amd64__ 895 case SHT_X86_64_UNWIND: 896 #endif 897 if ((shdr[i].sh_flags & SHF_ALLOC) == 0) 898 break; 899 alignmask = shdr[i].sh_addralign - 1; 900 mapsize += alignmask; 901 mapsize &= ~alignmask; 902 mapsize += shdr[i].sh_size; 903 break; 904 } 905 } 906 907 /* 908 * We know how much space we need for the text/data/bss/etc. 909 * This stuff needs to be in a single chunk so that profiling etc 910 * can get the bounds and gdb can associate offsets with modules 911 */ 912 ef->object = vm_pager_allocate(OBJT_PHYS, NULL, round_page(mapsize), 913 VM_PROT_ALL, 0, thread0.td_ucred); 914 if (ef->object == NULL) { 915 error = ENOMEM; 916 goto out; 917 } 918 #if VM_NRESERVLEVEL > 0 919 vm_object_color(ef->object, 0); 920 #endif 921 922 /* 923 * In order to satisfy amd64's architectural requirements on the 924 * location of code and data in the kernel's address space, request a 925 * mapping that is above the kernel. 926 * 927 * Protections will be restricted once relocations are applied. 928 */ 929 #ifdef __amd64__ 930 mapbase = KERNBASE; 931 #else 932 mapbase = VM_MIN_KERNEL_ADDRESS; 933 #endif 934 error = vm_map_find(kernel_map, ef->object, 0, &mapbase, 935 round_page(mapsize), 0, VMFS_OPTIMAL_SPACE, VM_PROT_ALL, 936 VM_PROT_ALL, 0); 937 if (error != KERN_SUCCESS) { 938 vm_object_deallocate(ef->object); 939 ef->object = NULL; 940 error = ENOMEM; 941 goto out; 942 } 943 944 /* Wire the pages */ 945 error = vm_map_wire(kernel_map, mapbase, 946 mapbase + round_page(mapsize), 947 VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES); 948 if (error != KERN_SUCCESS) { 949 error = ENOMEM; 950 goto out; 951 } 952 953 /* Inform the kld system about the situation */ 954 lf->address = ef->address = (caddr_t)mapbase; 955 lf->size = mapsize; 956 957 /* 958 * Now load code/data(progbits), zero bss(nobits), allocate space for 959 * and load relocs 960 */ 961 pb = 0; 962 rl = 0; 963 ra = 0; 964 alignmask = 0; 965 for (i = 0; i < hdr->e_shnum; i++) { 966 if (shdr[i].sh_size == 0) 967 continue; 968 switch (shdr[i].sh_type) { 969 case SHT_PROGBITS: 970 case SHT_NOBITS: 971 #ifdef __amd64__ 972 case SHT_X86_64_UNWIND: 973 #endif 974 if ((shdr[i].sh_flags & SHF_ALLOC) == 0) 975 break; 976 alignmask = shdr[i].sh_addralign - 1; 977 mapbase += alignmask; 978 mapbase &= ~alignmask; 979 if (ef->shstrtab != NULL && shdr[i].sh_name != 0) { 980 ef->progtab[pb].name = 981 ef->shstrtab + shdr[i].sh_name; 982 if (!strcmp(ef->progtab[pb].name, ".ctors")) { 983 lf->ctors_addr = (caddr_t)mapbase; 984 lf->ctors_size = shdr[i].sh_size; 985 } 986 } else if (shdr[i].sh_type == SHT_PROGBITS) 987 ef->progtab[pb].name = "<<PROGBITS>>"; 988 #ifdef __amd64__ 989 else if (shdr[i].sh_type == SHT_X86_64_UNWIND) 990 ef->progtab[pb].name = "<<UNWIND>>"; 991 #endif 992 else 993 ef->progtab[pb].name = "<<NOBITS>>"; 994 if (ef->progtab[pb].name != NULL && 995 !strcmp(ef->progtab[pb].name, DPCPU_SETNAME)) { 996 ef->progtab[pb].addr = 997 dpcpu_alloc(shdr[i].sh_size); 998 if (ef->progtab[pb].addr == NULL) { 999 printf("%s: pcpu module space is out " 1000 "of space; cannot allocate %#jx " 1001 "for %s\n", __func__, 1002 (uintmax_t)shdr[i].sh_size, 1003 filename); 1004 } 1005 } 1006 #ifdef VIMAGE 1007 else if (ef->progtab[pb].name != NULL && 1008 !strcmp(ef->progtab[pb].name, VNET_SETNAME)) { 1009 ef->progtab[pb].addr = 1010 vnet_data_alloc(shdr[i].sh_size); 1011 if (ef->progtab[pb].addr == NULL) { 1012 printf("%s: vnet module space is out " 1013 "of space; cannot allocate %#jx " 1014 "for %s\n", __func__, 1015 (uintmax_t)shdr[i].sh_size, 1016 filename); 1017 } 1018 } 1019 #endif 1020 else 1021 ef->progtab[pb].addr = 1022 (void *)(uintptr_t)mapbase; 1023 if (ef->progtab[pb].addr == NULL) { 1024 error = ENOSPC; 1025 goto out; 1026 } 1027 ef->progtab[pb].size = shdr[i].sh_size; 1028 ef->progtab[pb].flags = shdr[i].sh_flags; 1029 ef->progtab[pb].sec = i; 1030 if (shdr[i].sh_type == SHT_PROGBITS 1031 #ifdef __amd64__ 1032 || shdr[i].sh_type == SHT_X86_64_UNWIND 1033 #endif 1034 ) { 1035 error = vn_rdwr(UIO_READ, nd->ni_vp, 1036 ef->progtab[pb].addr, 1037 shdr[i].sh_size, shdr[i].sh_offset, 1038 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, 1039 NOCRED, &resid, td); 1040 if (error) 1041 goto out; 1042 if (resid != 0){ 1043 error = EINVAL; 1044 goto out; 1045 } 1046 /* Initialize the per-cpu or vnet area. */ 1047 if (ef->progtab[pb].addr != (void *)mapbase && 1048 !strcmp(ef->progtab[pb].name, DPCPU_SETNAME)) 1049 dpcpu_copy(ef->progtab[pb].addr, 1050 shdr[i].sh_size); 1051 #ifdef VIMAGE 1052 else if (ef->progtab[pb].addr != 1053 (void *)mapbase && 1054 !strcmp(ef->progtab[pb].name, VNET_SETNAME)) 1055 vnet_data_copy(ef->progtab[pb].addr, 1056 shdr[i].sh_size); 1057 #endif 1058 } else 1059 bzero(ef->progtab[pb].addr, shdr[i].sh_size); 1060 1061 /* Update all symbol values with the offset. */ 1062 for (j = 0; j < ef->ddbsymcnt; j++) { 1063 es = &ef->ddbsymtab[j]; 1064 if (es->st_shndx != i) 1065 continue; 1066 es->st_value += (Elf_Addr)ef->progtab[pb].addr; 1067 } 1068 mapbase += shdr[i].sh_size; 1069 pb++; 1070 break; 1071 case SHT_REL: 1072 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0) 1073 break; 1074 ef->reltab[rl].rel = malloc(shdr[i].sh_size, M_LINKER, 1075 M_WAITOK); 1076 ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel); 1077 ef->reltab[rl].sec = shdr[i].sh_info; 1078 error = vn_rdwr(UIO_READ, nd->ni_vp, 1079 (void *)ef->reltab[rl].rel, 1080 shdr[i].sh_size, shdr[i].sh_offset, 1081 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1082 &resid, td); 1083 if (error) 1084 goto out; 1085 if (resid != 0){ 1086 error = EINVAL; 1087 goto out; 1088 } 1089 rl++; 1090 break; 1091 case SHT_RELA: 1092 if ((shdr[shdr[i].sh_info].sh_flags & SHF_ALLOC) == 0) 1093 break; 1094 ef->relatab[ra].rela = malloc(shdr[i].sh_size, M_LINKER, 1095 M_WAITOK); 1096 ef->relatab[ra].nrela = 1097 shdr[i].sh_size / sizeof(Elf_Rela); 1098 ef->relatab[ra].sec = shdr[i].sh_info; 1099 error = vn_rdwr(UIO_READ, nd->ni_vp, 1100 (void *)ef->relatab[ra].rela, 1101 shdr[i].sh_size, shdr[i].sh_offset, 1102 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1103 &resid, td); 1104 if (error) 1105 goto out; 1106 if (resid != 0){ 1107 error = EINVAL; 1108 goto out; 1109 } 1110 ra++; 1111 break; 1112 } 1113 } 1114 if (pb != ef->nprogtab) { 1115 link_elf_error(filename, "lost progbits"); 1116 error = ENOEXEC; 1117 goto out; 1118 } 1119 if (rl != ef->nreltab) { 1120 link_elf_error(filename, "lost reltab"); 1121 error = ENOEXEC; 1122 goto out; 1123 } 1124 if (ra != ef->nrelatab) { 1125 link_elf_error(filename, "lost relatab"); 1126 error = ENOEXEC; 1127 goto out; 1128 } 1129 if (mapbase != (vm_offset_t)ef->address + mapsize) { 1130 printf( 1131 "%s: mapbase 0x%lx != address %p + mapsize 0x%lx (0x%lx)\n", 1132 filename != NULL ? filename : "<none>", 1133 (u_long)mapbase, ef->address, (u_long)mapsize, 1134 (u_long)(vm_offset_t)ef->address + mapsize); 1135 error = ENOMEM; 1136 goto out; 1137 } 1138 1139 /* Local intra-module relocations */ 1140 error = link_elf_reloc_local(lf, false); 1141 if (error != 0) 1142 goto out; 1143 1144 /* Pull in dependencies */ 1145 VOP_UNLOCK(nd->ni_vp); 1146 error = linker_load_dependencies(lf); 1147 vn_lock(nd->ni_vp, LK_EXCLUSIVE | LK_RETRY); 1148 if (error) 1149 goto out; 1150 1151 /* External relocations */ 1152 error = relocate_file(ef); 1153 if (error) 1154 goto out; 1155 1156 /* Notify MD code that a module is being loaded. */ 1157 error = elf_cpu_load_file(lf); 1158 if (error) 1159 goto out; 1160 1161 #if defined(__i386__) || defined(__amd64__) 1162 /* Now ifuncs. */ 1163 error = link_elf_reloc_local(lf, true); 1164 if (error != 0) 1165 goto out; 1166 #endif 1167 1168 link_elf_protect(ef); 1169 link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size); 1170 *result = lf; 1171 1172 out: 1173 VOP_UNLOCK(nd->ni_vp); 1174 vn_close(nd->ni_vp, FREAD, td->td_ucred, td); 1175 free(nd, M_TEMP); 1176 if (error && lf) 1177 linker_file_unload(lf, LINKER_UNLOAD_FORCE); 1178 free(hdr, M_LINKER); 1179 1180 return error; 1181 } 1182 1183 static void 1184 link_elf_unload_file(linker_file_t file) 1185 { 1186 elf_file_t ef = (elf_file_t) file; 1187 u_int i; 1188 1189 /* Notify MD code that a module is being unloaded. */ 1190 elf_cpu_unload_file(file); 1191 1192 if (ef->progtab) { 1193 for (i = 0; i < ef->nprogtab; i++) { 1194 if (ef->progtab[i].size == 0) 1195 continue; 1196 if (ef->progtab[i].name == NULL) 1197 continue; 1198 if (!strcmp(ef->progtab[i].name, DPCPU_SETNAME)) 1199 dpcpu_free(ef->progtab[i].addr, 1200 ef->progtab[i].size); 1201 #ifdef VIMAGE 1202 else if (!strcmp(ef->progtab[i].name, VNET_SETNAME)) 1203 vnet_data_free(ef->progtab[i].addr, 1204 ef->progtab[i].size); 1205 #endif 1206 } 1207 } 1208 if (ef->preloaded) { 1209 free(ef->reltab, M_LINKER); 1210 free(ef->relatab, M_LINKER); 1211 free(ef->progtab, M_LINKER); 1212 free(ef->ctftab, M_LINKER); 1213 free(ef->ctfoff, M_LINKER); 1214 free(ef->typoff, M_LINKER); 1215 if (file->pathname != NULL) 1216 preload_delete_name(file->pathname); 1217 return; 1218 } 1219 1220 for (i = 0; i < ef->nreltab; i++) 1221 free(ef->reltab[i].rel, M_LINKER); 1222 for (i = 0; i < ef->nrelatab; i++) 1223 free(ef->relatab[i].rela, M_LINKER); 1224 free(ef->reltab, M_LINKER); 1225 free(ef->relatab, M_LINKER); 1226 free(ef->progtab, M_LINKER); 1227 1228 if (ef->object != NULL) 1229 vm_map_remove(kernel_map, (vm_offset_t)ef->address, 1230 (vm_offset_t)ef->address + ptoa(ef->object->size)); 1231 free(ef->e_shdr, M_LINKER); 1232 free(ef->ddbsymtab, M_LINKER); 1233 free(ef->ddbstrtab, M_LINKER); 1234 free(ef->shstrtab, M_LINKER); 1235 free(ef->ctftab, M_LINKER); 1236 free(ef->ctfoff, M_LINKER); 1237 free(ef->typoff, M_LINKER); 1238 } 1239 1240 static const char * 1241 symbol_name(elf_file_t ef, Elf_Size r_info) 1242 { 1243 const Elf_Sym *ref; 1244 1245 if (ELF_R_SYM(r_info)) { 1246 ref = ef->ddbsymtab + ELF_R_SYM(r_info); 1247 return ef->ddbstrtab + ref->st_name; 1248 } else 1249 return NULL; 1250 } 1251 1252 static Elf_Addr 1253 findbase(elf_file_t ef, int sec) 1254 { 1255 int i; 1256 Elf_Addr base = 0; 1257 1258 for (i = 0; i < ef->nprogtab; i++) { 1259 if (sec == ef->progtab[i].sec) { 1260 base = (Elf_Addr)ef->progtab[i].addr; 1261 break; 1262 } 1263 } 1264 return base; 1265 } 1266 1267 static int 1268 relocate_file(elf_file_t ef) 1269 { 1270 const Elf_Rel *rellim; 1271 const Elf_Rel *rel; 1272 const Elf_Rela *relalim; 1273 const Elf_Rela *rela; 1274 const char *symname; 1275 const Elf_Sym *sym; 1276 int i; 1277 Elf_Size symidx; 1278 Elf_Addr base; 1279 1280 /* Perform relocations without addend if there are any: */ 1281 for (i = 0; i < ef->nreltab; i++) { 1282 rel = ef->reltab[i].rel; 1283 if (rel == NULL) { 1284 link_elf_error(ef->lf.filename, "lost a reltab!"); 1285 return (ENOEXEC); 1286 } 1287 rellim = rel + ef->reltab[i].nrel; 1288 base = findbase(ef, ef->reltab[i].sec); 1289 if (base == 0) { 1290 link_elf_error(ef->lf.filename, "lost base for reltab"); 1291 return (ENOEXEC); 1292 } 1293 for ( ; rel < rellim; rel++) { 1294 symidx = ELF_R_SYM(rel->r_info); 1295 if (symidx >= ef->ddbsymcnt) 1296 continue; 1297 sym = ef->ddbsymtab + symidx; 1298 /* Local relocs are already done */ 1299 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) 1300 continue; 1301 if (elf_reloc(&ef->lf, base, rel, ELF_RELOC_REL, 1302 elf_obj_lookup)) { 1303 symname = symbol_name(ef, rel->r_info); 1304 printf("link_elf_obj: symbol %s undefined\n", 1305 symname); 1306 return (ENOENT); 1307 } 1308 } 1309 } 1310 1311 /* Perform relocations with addend if there are any: */ 1312 for (i = 0; i < ef->nrelatab; i++) { 1313 rela = ef->relatab[i].rela; 1314 if (rela == NULL) { 1315 link_elf_error(ef->lf.filename, "lost a relatab!"); 1316 return (ENOEXEC); 1317 } 1318 relalim = rela + ef->relatab[i].nrela; 1319 base = findbase(ef, ef->relatab[i].sec); 1320 if (base == 0) { 1321 link_elf_error(ef->lf.filename, 1322 "lost base for relatab"); 1323 return (ENOEXEC); 1324 } 1325 for ( ; rela < relalim; rela++) { 1326 symidx = ELF_R_SYM(rela->r_info); 1327 if (symidx >= ef->ddbsymcnt) 1328 continue; 1329 sym = ef->ddbsymtab + symidx; 1330 /* Local relocs are already done */ 1331 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) 1332 continue; 1333 if (elf_reloc(&ef->lf, base, rela, ELF_RELOC_RELA, 1334 elf_obj_lookup)) { 1335 symname = symbol_name(ef, rela->r_info); 1336 printf("link_elf_obj: symbol %s undefined\n", 1337 symname); 1338 return (ENOENT); 1339 } 1340 } 1341 } 1342 1343 /* 1344 * Only clean SHN_FBSD_CACHED for successful return. If we 1345 * modified symbol table for the object but found an 1346 * unresolved symbol, there is no reason to roll back. 1347 */ 1348 elf_obj_cleanup_globals_cache(ef); 1349 1350 return (0); 1351 } 1352 1353 static int 1354 link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym) 1355 { 1356 elf_file_t ef = (elf_file_t) lf; 1357 const Elf_Sym *symp; 1358 const char *strp; 1359 int i; 1360 1361 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1362 strp = ef->ddbstrtab + symp->st_name; 1363 if (symp->st_shndx != SHN_UNDEF && strcmp(name, strp) == 0) { 1364 *sym = (c_linker_sym_t) symp; 1365 return 0; 1366 } 1367 } 1368 return ENOENT; 1369 } 1370 1371 static int 1372 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, 1373 linker_symval_t *symval) 1374 { 1375 elf_file_t ef; 1376 const Elf_Sym *es; 1377 caddr_t val; 1378 1379 ef = (elf_file_t) lf; 1380 es = (const Elf_Sym*) sym; 1381 val = (caddr_t)es->st_value; 1382 if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) { 1383 symval->name = ef->ddbstrtab + es->st_name; 1384 val = (caddr_t)es->st_value; 1385 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC) 1386 val = ((caddr_t (*)(void))val)(); 1387 symval->value = val; 1388 symval->size = es->st_size; 1389 return 0; 1390 } 1391 return ENOENT; 1392 } 1393 1394 static int 1395 link_elf_search_symbol(linker_file_t lf, caddr_t value, 1396 c_linker_sym_t *sym, long *diffp) 1397 { 1398 elf_file_t ef = (elf_file_t) lf; 1399 u_long off = (uintptr_t) (void *) value; 1400 u_long diff = off; 1401 u_long st_value; 1402 const Elf_Sym *es; 1403 const Elf_Sym *best = NULL; 1404 int i; 1405 1406 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) { 1407 if (es->st_name == 0) 1408 continue; 1409 st_value = es->st_value; 1410 if (off >= st_value) { 1411 if (off - st_value < diff) { 1412 diff = off - st_value; 1413 best = es; 1414 if (diff == 0) 1415 break; 1416 } else if (off - st_value == diff) { 1417 best = es; 1418 } 1419 } 1420 } 1421 if (best == NULL) 1422 *diffp = off; 1423 else 1424 *diffp = diff; 1425 *sym = (c_linker_sym_t) best; 1426 1427 return 0; 1428 } 1429 1430 /* 1431 * Look up a linker set on an ELF system. 1432 */ 1433 static int 1434 link_elf_lookup_set(linker_file_t lf, const char *name, 1435 void ***startp, void ***stopp, int *countp) 1436 { 1437 elf_file_t ef = (elf_file_t)lf; 1438 void **start, **stop; 1439 int i, count; 1440 1441 /* Relative to section number */ 1442 for (i = 0; i < ef->nprogtab; i++) { 1443 if ((strncmp(ef->progtab[i].name, "set_", 4) == 0) && 1444 strcmp(ef->progtab[i].name + 4, name) == 0) { 1445 start = (void **)ef->progtab[i].addr; 1446 stop = (void **)((char *)ef->progtab[i].addr + 1447 ef->progtab[i].size); 1448 count = stop - start; 1449 if (startp) 1450 *startp = start; 1451 if (stopp) 1452 *stopp = stop; 1453 if (countp) 1454 *countp = count; 1455 return (0); 1456 } 1457 } 1458 return (ESRCH); 1459 } 1460 1461 static int 1462 link_elf_each_function_name(linker_file_t file, 1463 int (*callback)(const char *, void *), void *opaque) 1464 { 1465 elf_file_t ef = (elf_file_t)file; 1466 const Elf_Sym *symp; 1467 int i, error; 1468 1469 /* Exhaustive search */ 1470 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1471 if (symp->st_value != 0 && 1472 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1473 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) { 1474 error = callback(ef->ddbstrtab + symp->st_name, opaque); 1475 if (error) 1476 return (error); 1477 } 1478 } 1479 return (0); 1480 } 1481 1482 static int 1483 link_elf_each_function_nameval(linker_file_t file, 1484 linker_function_nameval_callback_t callback, void *opaque) 1485 { 1486 linker_symval_t symval; 1487 elf_file_t ef = (elf_file_t)file; 1488 const Elf_Sym* symp; 1489 int i, error; 1490 1491 /* Exhaustive search */ 1492 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1493 if (symp->st_value != 0 && 1494 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1495 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) { 1496 error = link_elf_symbol_values(file, 1497 (c_linker_sym_t)symp, &symval); 1498 if (error) 1499 return (error); 1500 error = callback(file, i, &symval, opaque); 1501 if (error) 1502 return (error); 1503 } 1504 } 1505 return (0); 1506 } 1507 1508 static void 1509 elf_obj_cleanup_globals_cache(elf_file_t ef) 1510 { 1511 Elf_Sym *sym; 1512 Elf_Size i; 1513 1514 for (i = 0; i < ef->ddbsymcnt; i++) { 1515 sym = ef->ddbsymtab + i; 1516 if (sym->st_shndx == SHN_FBSD_CACHED) { 1517 sym->st_shndx = SHN_UNDEF; 1518 sym->st_value = 0; 1519 } 1520 } 1521 } 1522 1523 /* 1524 * Symbol lookup function that can be used when the symbol index is known (ie 1525 * in relocations). It uses the symbol index instead of doing a fully fledged 1526 * hash table based lookup when such is valid. For example for local symbols. 1527 * This is not only more efficient, it's also more correct. It's not always 1528 * the case that the symbol can be found through the hash table. 1529 */ 1530 static int 1531 elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res) 1532 { 1533 elf_file_t ef = (elf_file_t)lf; 1534 Elf_Sym *sym; 1535 const char *symbol; 1536 Elf_Addr res1; 1537 1538 /* Don't even try to lookup the symbol if the index is bogus. */ 1539 if (symidx >= ef->ddbsymcnt) { 1540 *res = 0; 1541 return (EINVAL); 1542 } 1543 1544 sym = ef->ddbsymtab + symidx; 1545 1546 /* Quick answer if there is a definition included. */ 1547 if (sym->st_shndx != SHN_UNDEF) { 1548 res1 = (Elf_Addr)sym->st_value; 1549 if (ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC) 1550 res1 = ((Elf_Addr (*)(void))res1)(); 1551 *res = res1; 1552 return (0); 1553 } 1554 1555 /* If we get here, then it is undefined and needs a lookup. */ 1556 switch (ELF_ST_BIND(sym->st_info)) { 1557 case STB_LOCAL: 1558 /* Local, but undefined? huh? */ 1559 *res = 0; 1560 return (EINVAL); 1561 1562 case STB_GLOBAL: 1563 case STB_WEAK: 1564 /* Relative to Data or Function name */ 1565 symbol = ef->ddbstrtab + sym->st_name; 1566 1567 /* Force a lookup failure if the symbol name is bogus. */ 1568 if (*symbol == 0) { 1569 *res = 0; 1570 return (EINVAL); 1571 } 1572 res1 = (Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps); 1573 1574 /* 1575 * Cache global lookups during module relocation. The failure 1576 * case is particularly expensive for callers, who must scan 1577 * through the entire globals table doing strcmp(). Cache to 1578 * avoid doing such work repeatedly. 1579 * 1580 * After relocation is complete, undefined globals will be 1581 * restored to SHN_UNDEF in elf_obj_cleanup_globals_cache(), 1582 * above. 1583 */ 1584 if (res1 != 0) { 1585 sym->st_shndx = SHN_FBSD_CACHED; 1586 sym->st_value = res1; 1587 *res = res1; 1588 return (0); 1589 } else if (ELF_ST_BIND(sym->st_info) == STB_WEAK) { 1590 sym->st_value = 0; 1591 *res = 0; 1592 return (0); 1593 } 1594 return (EINVAL); 1595 1596 default: 1597 return (EINVAL); 1598 } 1599 } 1600 1601 static void 1602 link_elf_fix_link_set(elf_file_t ef) 1603 { 1604 static const char startn[] = "__start_"; 1605 static const char stopn[] = "__stop_"; 1606 Elf_Sym *sym; 1607 const char *sym_name, *linkset_name; 1608 Elf_Addr startp, stopp; 1609 Elf_Size symidx; 1610 int start, i; 1611 1612 startp = stopp = 0; 1613 for (symidx = 1 /* zero entry is special */; 1614 symidx < ef->ddbsymcnt; symidx++) { 1615 sym = ef->ddbsymtab + symidx; 1616 if (sym->st_shndx != SHN_UNDEF) 1617 continue; 1618 1619 sym_name = ef->ddbstrtab + sym->st_name; 1620 if (strncmp(sym_name, startn, sizeof(startn) - 1) == 0) { 1621 start = 1; 1622 linkset_name = sym_name + sizeof(startn) - 1; 1623 } 1624 else if (strncmp(sym_name, stopn, sizeof(stopn) - 1) == 0) { 1625 start = 0; 1626 linkset_name = sym_name + sizeof(stopn) - 1; 1627 } 1628 else 1629 continue; 1630 1631 for (i = 0; i < ef->nprogtab; i++) { 1632 if (strcmp(ef->progtab[i].name, linkset_name) == 0) { 1633 startp = (Elf_Addr)ef->progtab[i].addr; 1634 stopp = (Elf_Addr)(startp + ef->progtab[i].size); 1635 break; 1636 } 1637 } 1638 if (i == ef->nprogtab) 1639 continue; 1640 1641 sym->st_value = start ? startp : stopp; 1642 sym->st_shndx = i; 1643 } 1644 } 1645 1646 static int 1647 link_elf_reloc_local(linker_file_t lf, bool ifuncs) 1648 { 1649 elf_file_t ef = (elf_file_t)lf; 1650 const Elf_Rel *rellim; 1651 const Elf_Rel *rel; 1652 const Elf_Rela *relalim; 1653 const Elf_Rela *rela; 1654 const Elf_Sym *sym; 1655 Elf_Addr base; 1656 int i; 1657 Elf_Size symidx; 1658 1659 link_elf_fix_link_set(ef); 1660 1661 /* Perform relocations without addend if there are any: */ 1662 for (i = 0; i < ef->nreltab; i++) { 1663 rel = ef->reltab[i].rel; 1664 if (rel == NULL) { 1665 link_elf_error(ef->lf.filename, "lost a reltab"); 1666 return (ENOEXEC); 1667 } 1668 rellim = rel + ef->reltab[i].nrel; 1669 base = findbase(ef, ef->reltab[i].sec); 1670 if (base == 0) { 1671 link_elf_error(ef->lf.filename, "lost base for reltab"); 1672 return (ENOEXEC); 1673 } 1674 for ( ; rel < rellim; rel++) { 1675 symidx = ELF_R_SYM(rel->r_info); 1676 if (symidx >= ef->ddbsymcnt) 1677 continue; 1678 sym = ef->ddbsymtab + symidx; 1679 /* Only do local relocs */ 1680 if (ELF_ST_BIND(sym->st_info) != STB_LOCAL) 1681 continue; 1682 if ((ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC || 1683 elf_is_ifunc_reloc(rel->r_info)) != ifuncs) 1684 continue; 1685 if (elf_reloc_local(lf, base, rel, ELF_RELOC_REL, 1686 elf_obj_lookup) != 0) 1687 return (ENOEXEC); 1688 } 1689 } 1690 1691 /* Perform relocations with addend if there are any: */ 1692 for (i = 0; i < ef->nrelatab; i++) { 1693 rela = ef->relatab[i].rela; 1694 if (rela == NULL) { 1695 link_elf_error(ef->lf.filename, "lost a relatab!"); 1696 return (ENOEXEC); 1697 } 1698 relalim = rela + ef->relatab[i].nrela; 1699 base = findbase(ef, ef->relatab[i].sec); 1700 if (base == 0) { 1701 link_elf_error(ef->lf.filename, "lost base for reltab"); 1702 return (ENOEXEC); 1703 } 1704 for ( ; rela < relalim; rela++) { 1705 symidx = ELF_R_SYM(rela->r_info); 1706 if (symidx >= ef->ddbsymcnt) 1707 continue; 1708 sym = ef->ddbsymtab + symidx; 1709 /* Only do local relocs */ 1710 if (ELF_ST_BIND(sym->st_info) != STB_LOCAL) 1711 continue; 1712 if ((ELF_ST_TYPE(sym->st_info) == STT_GNU_IFUNC || 1713 elf_is_ifunc_reloc(rela->r_info)) != ifuncs) 1714 continue; 1715 if (elf_reloc_local(lf, base, rela, ELF_RELOC_RELA, 1716 elf_obj_lookup) != 0) 1717 return (ENOEXEC); 1718 } 1719 } 1720 return (0); 1721 } 1722 1723 static long 1724 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab) 1725 { 1726 elf_file_t ef = (elf_file_t)lf; 1727 1728 *symtab = ef->ddbsymtab; 1729 1730 if (*symtab == NULL) 1731 return (0); 1732 1733 return (ef->ddbsymcnt); 1734 } 1735 1736 static long 1737 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab) 1738 { 1739 elf_file_t ef = (elf_file_t)lf; 1740 1741 *strtab = ef->ddbstrtab; 1742 1743 if (*strtab == NULL) 1744 return (0); 1745 1746 return (ef->ddbstrcnt); 1747 }
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