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