Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/kern/link_elf_obj.c
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1 /*- 2 * Copyright (c) 1998-2000 Doug Rabson 3 * Copyright (c) 2004 Peter Wemm 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 */ 27 28 #include <sys/cdefs.h> 29 __FBSDID("$FreeBSD$"); 30 31 #include "opt_ddb.h" 32 #include "opt_mac.h" 33 34 #include <sys/param.h> 35 #include <sys/systm.h> 36 #include <sys/kernel.h> 37 #include <sys/lock.h> 38 #include <sys/malloc.h> 39 #include <sys/mutex.h> 40 #include <sys/mount.h> 41 #include <sys/proc.h> 42 #include <sys/namei.h> 43 #include <sys/fcntl.h> 44 #include <sys/vnode.h> 45 #include <sys/linker.h> 46 47 #include <machine/elf.h> 48 49 #include <security/mac/mac_framework.h> 50 51 #include <vm/vm.h> 52 #include <vm/vm_param.h> 53 #include <vm/vm_object.h> 54 #include <vm/vm_kern.h> 55 #include <vm/vm_extern.h> 56 #include <vm/pmap.h> 57 #include <vm/vm_map.h> 58 59 #include <sys/link_elf.h> 60 61 #ifdef DDB_CTF 62 #include <net/zlib.h> 63 #endif 64 65 #include "linker_if.h" 66 67 typedef struct { 68 void *addr; 69 Elf_Off size; 70 int flags; 71 int sec; /* Original section */ 72 char *name; 73 } Elf_progent; 74 75 typedef struct { 76 Elf_Rel *rel; 77 int nrel; 78 int sec; 79 } Elf_relent; 80 81 typedef struct { 82 Elf_Rela *rela; 83 int nrela; 84 int sec; 85 } Elf_relaent; 86 87 88 typedef struct elf_file { 89 struct linker_file lf; /* Common fields */ 90 91 int preloaded; 92 caddr_t address; /* Relocation address */ 93 vm_object_t object; /* VM object to hold file pages */ 94 Elf_Shdr *e_shdr; 95 96 Elf_progent *progtab; 97 int nprogtab; 98 99 Elf_relaent *relatab; 100 int nrelatab; 101 102 Elf_relent *reltab; 103 int nreltab; 104 105 Elf_Sym *ddbsymtab; /* The symbol table we are using */ 106 long ddbsymcnt; /* Number of symbols */ 107 caddr_t ddbstrtab; /* String table */ 108 long ddbstrcnt; /* number of bytes in string table */ 109 110 caddr_t shstrtab; /* Section name string table */ 111 long shstrcnt; /* number of bytes in string table */ 112 113 caddr_t ctftab; /* CTF table */ 114 long ctfcnt; /* number of bytes in CTF table */ 115 caddr_t ctfoff; /* CTF offset table */ 116 caddr_t typoff; /* Type offset table */ 117 long typlen; /* Number of type entries. */ 118 119 } *elf_file_t; 120 121 #include <kern/kern_ctf.c> 122 123 static int link_elf_link_preload(linker_class_t cls, 124 const char *, linker_file_t *); 125 static int link_elf_link_preload_finish(linker_file_t); 126 static int link_elf_load_file(linker_class_t, const char *, linker_file_t *); 127 static int link_elf_lookup_symbol(linker_file_t, const char *, 128 c_linker_sym_t *); 129 static int link_elf_symbol_values(linker_file_t, c_linker_sym_t, 130 linker_symval_t *); 131 static int link_elf_search_symbol(linker_file_t, caddr_t value, 132 c_linker_sym_t *sym, long *diffp); 133 134 static void link_elf_unload_file(linker_file_t); 135 static int link_elf_lookup_set(linker_file_t, const char *, 136 void ***, void ***, int *); 137 static int link_elf_each_function_name(linker_file_t, 138 int (*)(const char *, void *), void *); 139 static int link_elf_each_function_nameval(linker_file_t, 140 linker_function_nameval_callback_t, 141 void *); 142 static void link_elf_reloc_local(linker_file_t); 143 144 static Elf_Addr elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps); 145 146 static kobj_method_t link_elf_methods[] = { 147 KOBJMETHOD(linker_lookup_symbol, link_elf_lookup_symbol), 148 KOBJMETHOD(linker_symbol_values, link_elf_symbol_values), 149 KOBJMETHOD(linker_search_symbol, link_elf_search_symbol), 150 KOBJMETHOD(linker_unload, link_elf_unload_file), 151 KOBJMETHOD(linker_load_file, link_elf_load_file), 152 KOBJMETHOD(linker_link_preload, link_elf_link_preload), 153 KOBJMETHOD(linker_link_preload_finish, link_elf_link_preload_finish), 154 KOBJMETHOD(linker_lookup_set, link_elf_lookup_set), 155 KOBJMETHOD(linker_each_function_name, link_elf_each_function_name), 156 KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval), 157 KOBJMETHOD(linker_ctf_get, link_elf_ctf_get), 158 { 0, 0 } 159 }; 160 161 static struct linker_class link_elf_class = { 162 #if ELF_TARG_CLASS == ELFCLASS32 163 "elf32_obj", 164 #else 165 "elf64_obj", 166 #endif 167 link_elf_methods, sizeof(struct elf_file) 168 }; 169 170 static int relocate_file(elf_file_t ef); 171 172 static void 173 link_elf_error(const char *filename, const char *s) 174 { 175 if (filename == NULL) 176 printf("kldload: %s\n", s); 177 else 178 printf("kldload: %s: %s\n", filename, s); 179 } 180 181 static void 182 link_elf_init(void *arg) 183 { 184 185 linker_add_class(&link_elf_class); 186 } 187 188 SYSINIT(link_elf_obj, SI_SUB_KLD, SI_ORDER_SECOND, link_elf_init, 0); 189 190 static int 191 link_elf_link_preload(linker_class_t cls, const char *filename, 192 linker_file_t *result) 193 { 194 Elf_Ehdr *hdr; 195 Elf_Shdr *shdr; 196 Elf_Sym *es; 197 void *modptr, *baseptr, *sizeptr; 198 char *type; 199 elf_file_t ef; 200 linker_file_t lf; 201 Elf_Addr off; 202 int error, i, j, pb, ra, rl, shstrindex, symstrindex, symtabindex; 203 204 /* Look to see if we have the file preloaded */ 205 modptr = preload_search_by_name(filename); 206 if (modptr == NULL) 207 return ENOENT; 208 209 type = (char *)preload_search_info(modptr, MODINFO_TYPE); 210 baseptr = preload_search_info(modptr, MODINFO_ADDR); 211 sizeptr = preload_search_info(modptr, MODINFO_SIZE); 212 hdr = (Elf_Ehdr *)preload_search_info(modptr, MODINFO_METADATA | 213 MODINFOMD_ELFHDR); 214 shdr = (Elf_Shdr *)preload_search_info(modptr, MODINFO_METADATA | 215 MODINFOMD_SHDR); 216 if (type == NULL || (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) 217 " obj module") != 0 && 218 strcmp(type, "elf obj module") != 0)) { 219 return (EFTYPE); 220 } 221 if (baseptr == NULL || sizeptr == NULL || hdr == NULL || 222 shdr == NULL) 223 return (EINVAL); 224 225 lf = linker_make_file(filename, &link_elf_class); 226 if (lf == NULL) 227 return (ENOMEM); 228 229 ef = (elf_file_t)lf; 230 ef->preloaded = 1; 231 ef->address = *(caddr_t *)baseptr; 232 lf->address = *(caddr_t *)baseptr; 233 lf->size = *(size_t *)sizeptr; 234 235 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS || 236 hdr->e_ident[EI_DATA] != ELF_TARG_DATA || 237 hdr->e_ident[EI_VERSION] != EV_CURRENT || 238 hdr->e_version != EV_CURRENT || 239 hdr->e_type != ET_REL || 240 hdr->e_machine != ELF_TARG_MACH) { 241 error = EFTYPE; 242 goto out; 243 } 244 ef->e_shdr = shdr; 245 246 /* Scan the section header for information and table sizing. */ 247 symtabindex = -1; 248 symstrindex = -1; 249 for (i = 0; i < hdr->e_shnum; i++) { 250 switch (shdr[i].sh_type) { 251 case SHT_PROGBITS: 252 case SHT_NOBITS: 253 ef->nprogtab++; 254 break; 255 case SHT_SYMTAB: 256 symtabindex = i; 257 symstrindex = shdr[i].sh_link; 258 break; 259 case SHT_REL: 260 ef->nreltab++; 261 break; 262 case SHT_RELA: 263 ef->nrelatab++; 264 break; 265 } 266 } 267 268 shstrindex = hdr->e_shstrndx; 269 if (ef->nprogtab == 0 || symstrindex < 0 || 270 symstrindex >= hdr->e_shnum || 271 shdr[symstrindex].sh_type != SHT_STRTAB || shstrindex == 0 || 272 shstrindex >= hdr->e_shnum || 273 shdr[shstrindex].sh_type != SHT_STRTAB) { 274 printf("%s: bad/missing section headers\n", filename); 275 error = ENOEXEC; 276 goto out; 277 } 278 279 /* Allocate space for tracking the load chunks */ 280 if (ef->nprogtab != 0) 281 ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab), 282 M_LINKER, M_WAITOK | M_ZERO); 283 if (ef->nreltab != 0) 284 ef->reltab = malloc(ef->nreltab * sizeof(*ef->reltab), 285 M_LINKER, M_WAITOK | M_ZERO); 286 if (ef->nrelatab != 0) 287 ef->relatab = malloc(ef->nrelatab * sizeof(*ef->relatab), 288 M_LINKER, M_WAITOK | M_ZERO); 289 if ((ef->nprogtab != 0 && ef->progtab == NULL) || 290 (ef->nreltab != 0 && ef->reltab == NULL) || 291 (ef->nrelatab != 0 && ef->relatab == NULL)) { 292 error = ENOMEM; 293 goto out; 294 } 295 296 /* XXX, relocate the sh_addr fields saved by the loader. */ 297 off = 0; 298 for (i = 0; i < hdr->e_shnum; i++) { 299 if (shdr[i].sh_addr != 0 && (off == 0 || shdr[i].sh_addr < off)) 300 off = shdr[i].sh_addr; 301 } 302 for (i = 0; i < hdr->e_shnum; i++) { 303 if (shdr[i].sh_addr != 0) 304 shdr[i].sh_addr = shdr[i].sh_addr - off + 305 (Elf_Addr)ef->address; 306 } 307 308 ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym); 309 ef->ddbsymtab = (Elf_Sym *)shdr[symtabindex].sh_addr; 310 ef->ddbstrcnt = shdr[symstrindex].sh_size; 311 ef->ddbstrtab = (char *)shdr[symstrindex].sh_addr; 312 ef->shstrcnt = shdr[shstrindex].sh_size; 313 ef->shstrtab = (char *)shdr[shstrindex].sh_addr; 314 315 /* Now fill out progtab and the relocation tables. */ 316 pb = 0; 317 rl = 0; 318 ra = 0; 319 for (i = 0; i < hdr->e_shnum; i++) { 320 switch (shdr[i].sh_type) { 321 case SHT_PROGBITS: 322 case SHT_NOBITS: 323 ef->progtab[pb].addr = (void *)shdr[i].sh_addr; 324 if (shdr[i].sh_type == SHT_PROGBITS) 325 ef->progtab[pb].name = "<<PROGBITS>>"; 326 else 327 ef->progtab[pb].name = "<<NOBITS>>"; 328 ef->progtab[pb].size = shdr[i].sh_size; 329 ef->progtab[pb].sec = i; 330 if (ef->shstrtab && shdr[i].sh_name != 0) 331 ef->progtab[pb].name = 332 ef->shstrtab + shdr[i].sh_name; 333 334 /* Update all symbol values with the offset. */ 335 for (j = 0; j < ef->ddbsymcnt; j++) { 336 es = &ef->ddbsymtab[j]; 337 if (es->st_shndx != i) 338 continue; 339 es->st_value += (Elf_Addr)ef->progtab[pb].addr; 340 } 341 pb++; 342 break; 343 case SHT_REL: 344 ef->reltab[rl].rel = (Elf_Rel *)shdr[i].sh_addr; 345 ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel); 346 ef->reltab[rl].sec = shdr[i].sh_info; 347 rl++; 348 break; 349 case SHT_RELA: 350 ef->relatab[ra].rela = (Elf_Rela *)shdr[i].sh_addr; 351 ef->relatab[ra].nrela = 352 shdr[i].sh_size / sizeof(Elf_Rela); 353 ef->relatab[ra].sec = shdr[i].sh_info; 354 ra++; 355 break; 356 } 357 } 358 if (pb != ef->nprogtab) 359 panic("lost progbits"); 360 if (rl != ef->nreltab) 361 panic("lost reltab"); 362 if (ra != ef->nrelatab) 363 panic("lost relatab"); 364 365 /* Local intra-module relocations */ 366 link_elf_reloc_local(lf); 367 368 *result = lf; 369 return (0); 370 371 out: 372 /* preload not done this way */ 373 linker_file_unload(lf, LINKER_UNLOAD_FORCE); 374 return (error); 375 } 376 377 static int 378 link_elf_link_preload_finish(linker_file_t lf) 379 { 380 elf_file_t ef; 381 int error; 382 383 ef = (elf_file_t)lf; 384 error = relocate_file(ef); 385 if (error) 386 return error; 387 388 /* Notify MD code that a module is being loaded. */ 389 error = elf_cpu_load_file(lf); 390 if (error) 391 return (error); 392 393 return (0); 394 } 395 396 static int 397 link_elf_load_file(linker_class_t cls, const char *filename, 398 linker_file_t *result) 399 { 400 struct nameidata nd; 401 struct thread *td = curthread; /* XXX */ 402 Elf_Ehdr *hdr; 403 Elf_Shdr *shdr; 404 Elf_Sym *es; 405 int nbytes, i, j; 406 vm_offset_t mapbase; 407 size_t mapsize; 408 int error = 0; 409 int resid, flags; 410 elf_file_t ef; 411 linker_file_t lf; 412 int symtabindex; 413 int symstrindex; 414 int shstrindex; 415 int nsym; 416 int pb, rl, ra; 417 int alignmask; 418 int vfslocked; 419 420 shdr = NULL; 421 lf = NULL; 422 mapsize = 0; 423 hdr = NULL; 424 425 NDINIT(&nd, LOOKUP, FOLLOW | MPSAFE, UIO_SYSSPACE, filename, td); 426 flags = FREAD; 427 error = vn_open(&nd, &flags, 0, NULL); 428 if (error) 429 return error; 430 vfslocked = NDHASGIANT(&nd); 431 NDFREE(&nd, NDF_ONLY_PNBUF); 432 if (nd.ni_vp->v_type != VREG) { 433 error = ENOEXEC; 434 goto out; 435 } 436 #ifdef MAC 437 error = mac_check_kld_load(td->td_ucred, nd.ni_vp); 438 if (error) { 439 goto out; 440 } 441 #endif 442 443 /* Read the elf header from the file. */ 444 hdr = malloc(sizeof(*hdr), M_LINKER, M_WAITOK); 445 if (hdr == NULL) { 446 error = ENOMEM; 447 goto out; 448 } 449 error = vn_rdwr(UIO_READ, nd.ni_vp, (void *)hdr, sizeof(*hdr), 0, 450 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 451 &resid, td); 452 if (error) 453 goto out; 454 if (resid != 0){ 455 error = ENOEXEC; 456 goto out; 457 } 458 459 if (!IS_ELF(*hdr)) { 460 error = ENOEXEC; 461 goto out; 462 } 463 464 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS 465 || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) { 466 link_elf_error(filename, "Unsupported file layout"); 467 error = ENOEXEC; 468 goto out; 469 } 470 if (hdr->e_ident[EI_VERSION] != EV_CURRENT 471 || hdr->e_version != EV_CURRENT) { 472 link_elf_error(filename, "Unsupported file version"); 473 error = ENOEXEC; 474 goto out; 475 } 476 if (hdr->e_type != ET_REL) { 477 link_elf_error(filename, "Unsupported file type"); 478 error = ENOEXEC; 479 goto out; 480 } 481 if (hdr->e_machine != ELF_TARG_MACH) { 482 link_elf_error(filename, "Unsupported machine"); 483 error = ENOEXEC; 484 goto out; 485 } 486 487 lf = linker_make_file(filename, &link_elf_class); 488 if (!lf) { 489 error = ENOMEM; 490 goto out; 491 } 492 ef = (elf_file_t) lf; 493 ef->nprogtab = 0; 494 ef->e_shdr = 0; 495 ef->nreltab = 0; 496 ef->nrelatab = 0; 497 498 /* Allocate and read in the section header */ 499 nbytes = hdr->e_shnum * hdr->e_shentsize; 500 if (nbytes == 0 || hdr->e_shoff == 0 || 501 hdr->e_shentsize != sizeof(Elf_Shdr)) { 502 error = ENOEXEC; 503 goto out; 504 } 505 shdr = malloc(nbytes, M_LINKER, M_WAITOK); 506 if (shdr == NULL) { 507 error = ENOMEM; 508 goto out; 509 } 510 ef->e_shdr = shdr; 511 error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)shdr, nbytes, hdr->e_shoff, 512 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, &resid, td); 513 if (error) 514 goto out; 515 if (resid) { 516 error = ENOEXEC; 517 goto out; 518 } 519 520 /* Scan the section header for information and table sizing. */ 521 nsym = 0; 522 symtabindex = -1; 523 symstrindex = -1; 524 for (i = 0; i < hdr->e_shnum; i++) { 525 if (shdr[i].sh_size == 0) 526 continue; 527 switch (shdr[i].sh_type) { 528 case SHT_PROGBITS: 529 case SHT_NOBITS: 530 ef->nprogtab++; 531 break; 532 case SHT_SYMTAB: 533 nsym++; 534 symtabindex = i; 535 symstrindex = shdr[i].sh_link; 536 break; 537 case SHT_REL: 538 ef->nreltab++; 539 break; 540 case SHT_RELA: 541 ef->nrelatab++; 542 break; 543 case SHT_STRTAB: 544 break; 545 } 546 } 547 if (ef->nprogtab == 0) { 548 link_elf_error(filename, "file has no contents"); 549 error = ENOEXEC; 550 goto out; 551 } 552 if (nsym != 1) { 553 /* Only allow one symbol table for now */ 554 link_elf_error(filename, "file has no valid symbol table"); 555 error = ENOEXEC; 556 goto out; 557 } 558 if (symstrindex < 0 || symstrindex > hdr->e_shnum || 559 shdr[symstrindex].sh_type != SHT_STRTAB) { 560 link_elf_error(filename, "file has invalid symbol strings"); 561 error = ENOEXEC; 562 goto out; 563 } 564 565 /* Allocate space for tracking the load chunks */ 566 if (ef->nprogtab != 0) 567 ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab), 568 M_LINKER, M_WAITOK | M_ZERO); 569 if (ef->nreltab != 0) 570 ef->reltab = malloc(ef->nreltab * sizeof(*ef->reltab), 571 M_LINKER, M_WAITOK | M_ZERO); 572 if (ef->nrelatab != 0) 573 ef->relatab = malloc(ef->nrelatab * sizeof(*ef->relatab), 574 M_LINKER, M_WAITOK | M_ZERO); 575 if ((ef->nprogtab != 0 && ef->progtab == NULL) || 576 (ef->nreltab != 0 && ef->reltab == NULL) || 577 (ef->nrelatab != 0 && ef->relatab == NULL)) { 578 error = ENOMEM; 579 goto out; 580 } 581 582 if (symtabindex == -1) 583 panic("lost symbol table index"); 584 /* Allocate space for and load the symbol table */ 585 ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym); 586 ef->ddbsymtab = malloc(shdr[symtabindex].sh_size, M_LINKER, M_WAITOK); 587 if (ef->ddbsymtab == NULL) { 588 error = ENOMEM; 589 goto out; 590 } 591 error = vn_rdwr(UIO_READ, nd.ni_vp, (void *)ef->ddbsymtab, 592 shdr[symtabindex].sh_size, shdr[symtabindex].sh_offset, 593 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 594 &resid, td); 595 if (error) 596 goto out; 597 if (resid != 0){ 598 error = EINVAL; 599 goto out; 600 } 601 602 if (symstrindex == -1) 603 panic("lost symbol string index"); 604 /* Allocate space for and load the symbol strings */ 605 ef->ddbstrcnt = shdr[symstrindex].sh_size; 606 ef->ddbstrtab = malloc(shdr[symstrindex].sh_size, M_LINKER, M_WAITOK); 607 if (ef->ddbstrtab == NULL) { 608 error = ENOMEM; 609 goto out; 610 } 611 error = vn_rdwr(UIO_READ, nd.ni_vp, ef->ddbstrtab, 612 shdr[symstrindex].sh_size, shdr[symstrindex].sh_offset, 613 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 614 &resid, td); 615 if (error) 616 goto out; 617 if (resid != 0){ 618 error = EINVAL; 619 goto out; 620 } 621 622 /* Do we have a string table for the section names? */ 623 shstrindex = -1; 624 if (hdr->e_shstrndx != 0 && 625 shdr[hdr->e_shstrndx].sh_type == SHT_STRTAB) { 626 shstrindex = hdr->e_shstrndx; 627 ef->shstrcnt = shdr[shstrindex].sh_size; 628 ef->shstrtab = malloc(shdr[shstrindex].sh_size, M_LINKER, 629 M_WAITOK); 630 if (ef->shstrtab == NULL) { 631 error = ENOMEM; 632 goto out; 633 } 634 error = vn_rdwr(UIO_READ, nd.ni_vp, ef->shstrtab, 635 shdr[shstrindex].sh_size, shdr[shstrindex].sh_offset, 636 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 637 &resid, td); 638 if (error) 639 goto out; 640 if (resid != 0){ 641 error = EINVAL; 642 goto out; 643 } 644 } 645 646 /* Size up code/data(progbits) and bss(nobits). */ 647 alignmask = 0; 648 for (i = 0; i < hdr->e_shnum; i++) { 649 if (shdr[i].sh_size == 0) 650 continue; 651 switch (shdr[i].sh_type) { 652 case SHT_PROGBITS: 653 case SHT_NOBITS: 654 alignmask = shdr[i].sh_addralign - 1; 655 mapsize += alignmask; 656 mapsize &= ~alignmask; 657 mapsize += shdr[i].sh_size; 658 break; 659 } 660 } 661 662 /* 663 * We know how much space we need for the text/data/bss/etc. 664 * This stuff needs to be in a single chunk so that profiling etc 665 * can get the bounds and gdb can associate offsets with modules 666 */ 667 ef->object = vm_object_allocate(OBJT_DEFAULT, 668 round_page(mapsize) >> PAGE_SHIFT); 669 if (ef->object == NULL) { 670 error = ENOMEM; 671 goto out; 672 } 673 ef->address = (caddr_t) vm_map_min(kernel_map); 674 675 /* 676 * In order to satisfy amd64's architectural requirements on the 677 * location of code and data in the kernel's address space, request a 678 * mapping that is above the kernel. 679 */ 680 mapbase = KERNBASE; 681 error = vm_map_find(kernel_map, ef->object, 0, &mapbase, 682 round_page(mapsize), TRUE, VM_PROT_ALL, VM_PROT_ALL, FALSE); 683 if (error) { 684 vm_object_deallocate(ef->object); 685 ef->object = 0; 686 goto out; 687 } 688 689 /* Wire the pages */ 690 error = vm_map_wire(kernel_map, mapbase, 691 mapbase + round_page(mapsize), 692 VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES); 693 if (error != KERN_SUCCESS) { 694 error = ENOMEM; 695 goto out; 696 } 697 698 /* Inform the kld system about the situation */ 699 lf->address = ef->address = (caddr_t)mapbase; 700 lf->size = mapsize; 701 702 /* 703 * Now load code/data(progbits), zero bss(nobits), allocate space for 704 * and load relocs 705 */ 706 pb = 0; 707 rl = 0; 708 ra = 0; 709 alignmask = 0; 710 for (i = 0; i < hdr->e_shnum; i++) { 711 if (shdr[i].sh_size == 0) 712 continue; 713 switch (shdr[i].sh_type) { 714 case SHT_PROGBITS: 715 case SHT_NOBITS: 716 alignmask = shdr[i].sh_addralign - 1; 717 mapbase += alignmask; 718 mapbase &= ~alignmask; 719 ef->progtab[pb].addr = (void *)(uintptr_t)mapbase; 720 if (shdr[i].sh_type == SHT_PROGBITS) { 721 ef->progtab[pb].name = "<<PROGBITS>>"; 722 error = vn_rdwr(UIO_READ, nd.ni_vp, 723 ef->progtab[pb].addr, 724 shdr[i].sh_size, shdr[i].sh_offset, 725 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, 726 NOCRED, &resid, td); 727 if (error) 728 goto out; 729 if (resid != 0){ 730 error = EINVAL; 731 goto out; 732 } 733 } else { 734 ef->progtab[pb].name = "<<NOBITS>>"; 735 bzero(ef->progtab[pb].addr, shdr[i].sh_size); 736 } 737 ef->progtab[pb].size = shdr[i].sh_size; 738 ef->progtab[pb].sec = i; 739 if (ef->shstrtab && shdr[i].sh_name != 0) 740 ef->progtab[pb].name = 741 ef->shstrtab + shdr[i].sh_name; 742 743 /* Update all symbol values with the offset. */ 744 for (j = 0; j < ef->ddbsymcnt; j++) { 745 es = &ef->ddbsymtab[j]; 746 if (es->st_shndx != i) 747 continue; 748 es->st_value += (Elf_Addr)ef->progtab[pb].addr; 749 } 750 mapbase += shdr[i].sh_size; 751 pb++; 752 break; 753 case SHT_REL: 754 ef->reltab[rl].rel = malloc(shdr[i].sh_size, M_LINKER, 755 M_WAITOK); 756 ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel); 757 ef->reltab[rl].sec = shdr[i].sh_info; 758 error = vn_rdwr(UIO_READ, nd.ni_vp, 759 (void *)ef->reltab[rl].rel, 760 shdr[i].sh_size, shdr[i].sh_offset, 761 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 762 &resid, td); 763 if (error) 764 goto out; 765 if (resid != 0){ 766 error = EINVAL; 767 goto out; 768 } 769 rl++; 770 break; 771 case SHT_RELA: 772 ef->relatab[ra].rela = malloc(shdr[i].sh_size, M_LINKER, 773 M_WAITOK); 774 ef->relatab[ra].nrela = 775 shdr[i].sh_size / sizeof(Elf_Rela); 776 ef->relatab[ra].sec = shdr[i].sh_info; 777 error = vn_rdwr(UIO_READ, nd.ni_vp, 778 (void *)ef->relatab[ra].rela, 779 shdr[i].sh_size, shdr[i].sh_offset, 780 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 781 &resid, td); 782 if (error) 783 goto out; 784 if (resid != 0){ 785 error = EINVAL; 786 goto out; 787 } 788 ra++; 789 break; 790 } 791 } 792 if (pb != ef->nprogtab) 793 panic("lost progbits"); 794 if (rl != ef->nreltab) 795 panic("lost reltab"); 796 if (ra != ef->nrelatab) 797 panic("lost relatab"); 798 if (mapbase != (vm_offset_t)ef->address + mapsize) 799 panic("mapbase 0x%lx != address %p + mapsize 0x%lx (0x%lx)\n", 800 mapbase, ef->address, mapsize, 801 (vm_offset_t)ef->address + mapsize); 802 803 /* Local intra-module relocations */ 804 link_elf_reloc_local(lf); 805 806 /* Pull in dependencies */ 807 VOP_UNLOCK(nd.ni_vp, 0, td); 808 error = linker_load_dependencies(lf); 809 vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY, td); 810 if (error) 811 goto out; 812 813 /* External relocations */ 814 error = relocate_file(ef); 815 if (error) 816 goto out; 817 818 /* Notify MD code that a module is being loaded. */ 819 error = elf_cpu_load_file(lf); 820 if (error) 821 goto out; 822 823 *result = lf; 824 825 out: 826 if (error && lf) 827 linker_file_unload(lf, LINKER_UNLOAD_FORCE); 828 if (hdr) 829 free(hdr, M_LINKER); 830 VOP_UNLOCK(nd.ni_vp, 0, td); 831 vn_close(nd.ni_vp, FREAD, td->td_ucred, td); 832 VFS_UNLOCK_GIANT(vfslocked); 833 834 return error; 835 } 836 837 static void 838 link_elf_unload_file(linker_file_t file) 839 { 840 elf_file_t ef = (elf_file_t) file; 841 int i; 842 843 /* Notify MD code that a module is being unloaded. */ 844 elf_cpu_unload_file(file); 845 846 if (ef->preloaded) { 847 if (ef->reltab) 848 free(ef->reltab, M_LINKER); 849 if (ef->relatab) 850 free(ef->relatab, M_LINKER); 851 if (ef->progtab) 852 free(ef->progtab, M_LINKER); 853 if (ef->ctftab) 854 free(ef->ctftab, M_LINKER); 855 if (ef->ctfoff) 856 free(ef->ctfoff, M_LINKER); 857 if (ef->typoff) 858 free(ef->typoff, M_LINKER); 859 if (file->filename != NULL) 860 preload_delete_name(file->filename); 861 /* XXX reclaim module memory? */ 862 return; 863 } 864 865 for (i = 0; i < ef->nreltab; i++) 866 if (ef->reltab[i].rel) 867 free(ef->reltab[i].rel, M_LINKER); 868 for (i = 0; i < ef->nrelatab; i++) 869 if (ef->relatab[i].rela) 870 free(ef->relatab[i].rela, M_LINKER); 871 if (ef->reltab) 872 free(ef->reltab, M_LINKER); 873 if (ef->relatab) 874 free(ef->relatab, M_LINKER); 875 if (ef->progtab) 876 free(ef->progtab, M_LINKER); 877 878 if (ef->object) { 879 vm_map_remove(kernel_map, (vm_offset_t) ef->address, 880 (vm_offset_t) ef->address + 881 (ef->object->size << PAGE_SHIFT)); 882 } 883 if (ef->e_shdr) 884 free(ef->e_shdr, M_LINKER); 885 if (ef->ddbsymtab) 886 free(ef->ddbsymtab, M_LINKER); 887 if (ef->ddbstrtab) 888 free(ef->ddbstrtab, M_LINKER); 889 if (ef->shstrtab) 890 free(ef->shstrtab, M_LINKER); 891 if (ef->ctftab) 892 free(ef->ctftab, M_LINKER); 893 if (ef->ctfoff) 894 free(ef->ctfoff, M_LINKER); 895 if (ef->typoff) 896 free(ef->typoff, M_LINKER); 897 } 898 899 static const char * 900 symbol_name(elf_file_t ef, Elf_Size r_info) 901 { 902 const Elf_Sym *ref; 903 904 if (ELF_R_SYM(r_info)) { 905 ref = ef->ddbsymtab + ELF_R_SYM(r_info); 906 return ef->ddbstrtab + ref->st_name; 907 } else 908 return NULL; 909 } 910 911 static Elf_Addr 912 findbase(elf_file_t ef, int sec) 913 { 914 int i; 915 Elf_Addr base = 0; 916 917 for (i = 0; i < ef->nprogtab; i++) { 918 if (sec == ef->progtab[i].sec) { 919 base = (Elf_Addr)ef->progtab[i].addr; 920 break; 921 } 922 } 923 return base; 924 } 925 926 static int 927 relocate_file(elf_file_t ef) 928 { 929 const Elf_Rel *rellim; 930 const Elf_Rel *rel; 931 const Elf_Rela *relalim; 932 const Elf_Rela *rela; 933 const char *symname; 934 const Elf_Sym *sym; 935 int i; 936 Elf_Size symidx; 937 Elf_Addr base; 938 939 940 /* Perform relocations without addend if there are any: */ 941 for (i = 0; i < ef->nreltab; i++) { 942 rel = ef->reltab[i].rel; 943 if (rel == NULL) 944 panic("lost a reltab!"); 945 rellim = rel + ef->reltab[i].nrel; 946 base = findbase(ef, ef->reltab[i].sec); 947 if (base == 0) 948 panic("lost base for reltab"); 949 for ( ; rel < rellim; rel++) { 950 symidx = ELF_R_SYM(rel->r_info); 951 if (symidx >= ef->ddbsymcnt) 952 continue; 953 sym = ef->ddbsymtab + symidx; 954 /* Local relocs are already done */ 955 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) 956 continue; 957 if (elf_reloc(&ef->lf, base, rel, ELF_RELOC_REL, 958 elf_obj_lookup)) { 959 symname = symbol_name(ef, rel->r_info); 960 printf("link_elf_obj: symbol %s undefined\n", 961 symname); 962 return ENOENT; 963 } 964 } 965 } 966 967 /* Perform relocations with addend if there are any: */ 968 for (i = 0; i < ef->nrelatab; i++) { 969 rela = ef->relatab[i].rela; 970 if (rela == NULL) 971 panic("lost a relatab!"); 972 relalim = rela + ef->relatab[i].nrela; 973 base = findbase(ef, ef->relatab[i].sec); 974 if (base == 0) 975 panic("lost base for relatab"); 976 for ( ; rela < relalim; rela++) { 977 symidx = ELF_R_SYM(rela->r_info); 978 if (symidx >= ef->ddbsymcnt) 979 continue; 980 sym = ef->ddbsymtab + symidx; 981 /* Local relocs are already done */ 982 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) 983 continue; 984 if (elf_reloc(&ef->lf, base, rela, ELF_RELOC_RELA, 985 elf_obj_lookup)) { 986 symname = symbol_name(ef, rela->r_info); 987 printf("link_elf_obj: symbol %s undefined\n", 988 symname); 989 return ENOENT; 990 } 991 } 992 } 993 994 return 0; 995 } 996 997 static int 998 link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym) 999 { 1000 elf_file_t ef = (elf_file_t) lf; 1001 const Elf_Sym *symp; 1002 const char *strp; 1003 int i; 1004 1005 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1006 strp = ef->ddbstrtab + symp->st_name; 1007 if (symp->st_shndx != SHN_UNDEF && strcmp(name, strp) == 0) { 1008 *sym = (c_linker_sym_t) symp; 1009 return 0; 1010 } 1011 } 1012 return ENOENT; 1013 } 1014 1015 static int 1016 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, 1017 linker_symval_t *symval) 1018 { 1019 elf_file_t ef = (elf_file_t) lf; 1020 const Elf_Sym *es = (const Elf_Sym*) sym; 1021 1022 if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) { 1023 symval->name = ef->ddbstrtab + es->st_name; 1024 symval->value = (caddr_t)es->st_value; 1025 symval->size = es->st_size; 1026 return 0; 1027 } 1028 return ENOENT; 1029 } 1030 1031 static int 1032 link_elf_search_symbol(linker_file_t lf, caddr_t value, 1033 c_linker_sym_t *sym, long *diffp) 1034 { 1035 elf_file_t ef = (elf_file_t) lf; 1036 u_long off = (uintptr_t) (void *) value; 1037 u_long diff = off; 1038 u_long st_value; 1039 const Elf_Sym *es; 1040 const Elf_Sym *best = 0; 1041 int i; 1042 1043 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) { 1044 if (es->st_name == 0) 1045 continue; 1046 st_value = es->st_value; 1047 if (off >= st_value) { 1048 if (off - st_value < diff) { 1049 diff = off - st_value; 1050 best = es; 1051 if (diff == 0) 1052 break; 1053 } else if (off - st_value == diff) { 1054 best = es; 1055 } 1056 } 1057 } 1058 if (best == 0) 1059 *diffp = off; 1060 else 1061 *diffp = diff; 1062 *sym = (c_linker_sym_t) best; 1063 1064 return 0; 1065 } 1066 1067 /* 1068 * Look up a linker set on an ELF system. 1069 */ 1070 static int 1071 link_elf_lookup_set(linker_file_t lf, const char *name, 1072 void ***startp, void ***stopp, int *countp) 1073 { 1074 elf_file_t ef = (elf_file_t)lf; 1075 void **start, **stop; 1076 int i, count; 1077 1078 /* Relative to section number */ 1079 for (i = 0; i < ef->nprogtab; i++) { 1080 if ((strncmp(ef->progtab[i].name, "set_", 4) == 0) && 1081 strcmp(ef->progtab[i].name + 4, name) == 0) { 1082 start = (void **)ef->progtab[i].addr; 1083 stop = (void **)((char *)ef->progtab[i].addr + 1084 ef->progtab[i].size); 1085 count = stop - start; 1086 if (startp) 1087 *startp = start; 1088 if (stopp) 1089 *stopp = stop; 1090 if (countp) 1091 *countp = count; 1092 return (0); 1093 } 1094 } 1095 return (ESRCH); 1096 } 1097 1098 static int 1099 link_elf_each_function_name(linker_file_t file, 1100 int (*callback)(const char *, void *), void *opaque) 1101 { 1102 elf_file_t ef = (elf_file_t)file; 1103 const Elf_Sym *symp; 1104 int i, error; 1105 1106 /* Exhaustive search */ 1107 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1108 if (symp->st_value != 0 && 1109 ELF_ST_TYPE(symp->st_info) == STT_FUNC) { 1110 error = callback(ef->ddbstrtab + symp->st_name, opaque); 1111 if (error) 1112 return (error); 1113 } 1114 } 1115 return (0); 1116 } 1117 1118 static int 1119 link_elf_each_function_nameval(linker_file_t file, 1120 linker_function_nameval_callback_t callback, void *opaque) 1121 { 1122 linker_symval_t symval; 1123 elf_file_t ef = (elf_file_t)file; 1124 const Elf_Sym* symp; 1125 int i, error; 1126 1127 /* Exhaustive search */ 1128 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1129 if (symp->st_value != 0 && 1130 ELF_ST_TYPE(symp->st_info) == STT_FUNC) { 1131 error = link_elf_symbol_values(file, (c_linker_sym_t) symp, &symval); 1132 if (error) 1133 return (error); 1134 error = callback(file, i, &symval, opaque); 1135 if (error) 1136 return (error); 1137 } 1138 } 1139 return (0); 1140 } 1141 1142 /* 1143 * Symbol lookup function that can be used when the symbol index is known (ie 1144 * in relocations). It uses the symbol index instead of doing a fully fledged 1145 * hash table based lookup when such is valid. For example for local symbols. 1146 * This is not only more efficient, it's also more correct. It's not always 1147 * the case that the symbol can be found through the hash table. 1148 */ 1149 static Elf_Addr 1150 elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps) 1151 { 1152 elf_file_t ef = (elf_file_t)lf; 1153 const Elf_Sym *sym; 1154 const char *symbol; 1155 Elf_Addr ret; 1156 1157 /* Don't even try to lookup the symbol if the index is bogus. */ 1158 if (symidx >= ef->ddbsymcnt) 1159 return (0); 1160 1161 sym = ef->ddbsymtab + symidx; 1162 1163 /* Quick answer if there is a definition included. */ 1164 if (sym->st_shndx != SHN_UNDEF) 1165 return (sym->st_value); 1166 1167 /* If we get here, then it is undefined and needs a lookup. */ 1168 switch (ELF_ST_BIND(sym->st_info)) { 1169 case STB_LOCAL: 1170 /* Local, but undefined? huh? */ 1171 return (0); 1172 1173 case STB_GLOBAL: 1174 /* Relative to Data or Function name */ 1175 symbol = ef->ddbstrtab + sym->st_name; 1176 1177 /* Force a lookup failure if the symbol name is bogus. */ 1178 if (*symbol == 0) 1179 return (0); 1180 ret = ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps)); 1181 return ret; 1182 1183 case STB_WEAK: 1184 printf("link_elf_obj: Weak symbols not supported\n"); 1185 return (0); 1186 1187 default: 1188 return (0); 1189 } 1190 } 1191 1192 static void 1193 link_elf_fix_link_set(elf_file_t ef) 1194 { 1195 static const char startn[] = "__start_"; 1196 static const char stopn[] = "__stop_"; 1197 Elf_Sym *sym; 1198 const char *sym_name, *linkset_name; 1199 Elf_Addr startp, stopp; 1200 Elf_Size symidx; 1201 int start, i; 1202 1203 startp = stopp = 0; 1204 for (symidx = 1 /* zero entry is special */; 1205 symidx < ef->ddbsymcnt; symidx++) { 1206 sym = ef->ddbsymtab + symidx; 1207 if (sym->st_shndx != SHN_UNDEF) 1208 continue; 1209 1210 sym_name = ef->ddbstrtab + sym->st_name; 1211 if (strncmp(sym_name, startn, sizeof(startn) - 1) == 0) { 1212 start = 1; 1213 linkset_name = sym_name + sizeof(startn) - 1; 1214 } 1215 else if (strncmp(sym_name, stopn, sizeof(stopn) - 1) == 0) { 1216 start = 0; 1217 linkset_name = sym_name + sizeof(stopn) - 1; 1218 } 1219 else 1220 continue; 1221 1222 for (i = 0; i < ef->nprogtab; i++) { 1223 if (strcmp(ef->progtab[i].name, linkset_name) == 0) { 1224 startp = (Elf_Addr)ef->progtab[i].addr; 1225 stopp = (Elf_Addr)(startp + ef->progtab[i].size); 1226 break; 1227 } 1228 } 1229 if (i == ef->nprogtab) 1230 continue; 1231 1232 sym->st_value = start ? startp : stopp; 1233 sym->st_shndx = i; 1234 } 1235 } 1236 1237 static void 1238 link_elf_reloc_local(linker_file_t lf) 1239 { 1240 elf_file_t ef = (elf_file_t)lf; 1241 const Elf_Rel *rellim; 1242 const Elf_Rel *rel; 1243 const Elf_Rela *relalim; 1244 const Elf_Rela *rela; 1245 const Elf_Sym *sym; 1246 Elf_Addr base; 1247 int i; 1248 Elf_Size symidx; 1249 1250 link_elf_fix_link_set(ef); 1251 1252 /* Perform relocations without addend if there are any: */ 1253 for (i = 0; i < ef->nreltab; i++) { 1254 rel = ef->reltab[i].rel; 1255 if (rel == NULL) 1256 panic("lost a reltab!"); 1257 rellim = rel + ef->reltab[i].nrel; 1258 base = findbase(ef, ef->reltab[i].sec); 1259 if (base == 0) 1260 panic("lost base for reltab"); 1261 for ( ; rel < rellim; rel++) { 1262 symidx = ELF_R_SYM(rel->r_info); 1263 if (symidx >= ef->ddbsymcnt) 1264 continue; 1265 sym = ef->ddbsymtab + symidx; 1266 /* Only do local relocs */ 1267 if (ELF_ST_BIND(sym->st_info) != STB_LOCAL) 1268 continue; 1269 elf_reloc_local(lf, base, rel, ELF_RELOC_REL, 1270 elf_obj_lookup); 1271 } 1272 } 1273 1274 /* Perform relocations with addend if there are any: */ 1275 for (i = 0; i < ef->nrelatab; i++) { 1276 rela = ef->relatab[i].rela; 1277 if (rela == NULL) 1278 panic("lost a relatab!"); 1279 relalim = rela + ef->relatab[i].nrela; 1280 base = findbase(ef, ef->relatab[i].sec); 1281 if (base == 0) 1282 panic("lost base for relatab"); 1283 for ( ; rela < relalim; rela++) { 1284 symidx = ELF_R_SYM(rela->r_info); 1285 if (symidx >= ef->ddbsymcnt) 1286 continue; 1287 sym = ef->ddbsymtab + symidx; 1288 /* Only do local relocs */ 1289 if (ELF_ST_BIND(sym->st_info) != STB_LOCAL) 1290 continue; 1291 elf_reloc_local(lf, base, rela, ELF_RELOC_RELA, 1292 elf_obj_lookup); 1293 } 1294 } 1295 }
Cache object: fca9ebbbc06191bd5e250c36a8255903
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