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 #include "linker_if.h" 62 63 typedef struct { 64 void *addr; 65 Elf_Off size; 66 int flags; 67 int sec; /* Original section */ 68 char *name; 69 } Elf_progent; 70 71 typedef struct { 72 Elf_Rel *rel; 73 int nrel; 74 int sec; 75 } Elf_relent; 76 77 typedef struct { 78 Elf_Rela *rela; 79 int nrela; 80 int sec; 81 } Elf_relaent; 82 83 84 typedef struct elf_file { 85 struct linker_file lf; /* Common fields */ 86 87 int preloaded; 88 caddr_t address; /* Relocation address */ 89 vm_object_t object; /* VM object to hold file pages */ 90 Elf_Shdr *e_shdr; 91 92 Elf_progent *progtab; 93 int nprogtab; 94 95 Elf_relaent *relatab; 96 int nrela; 97 98 Elf_relent *reltab; 99 int nrel; 100 101 Elf_Sym *ddbsymtab; /* The symbol table we are using */ 102 long ddbsymcnt; /* Number of symbols */ 103 caddr_t ddbstrtab; /* String table */ 104 long ddbstrcnt; /* number of bytes in string table */ 105 106 caddr_t shstrtab; /* Section name string table */ 107 long shstrcnt; /* number of bytes in string table */ 108 109 } *elf_file_t; 110 111 static int link_elf_link_preload(linker_class_t cls, 112 const char *, linker_file_t *); 113 static int link_elf_link_preload_finish(linker_file_t); 114 static int link_elf_load_file(linker_class_t, const char *, linker_file_t *); 115 static int link_elf_lookup_symbol(linker_file_t, const char *, 116 c_linker_sym_t *); 117 static int link_elf_symbol_values(linker_file_t, c_linker_sym_t, 118 linker_symval_t *); 119 static int link_elf_search_symbol(linker_file_t, caddr_t value, 120 c_linker_sym_t *sym, long *diffp); 121 122 static void link_elf_unload_file(linker_file_t); 123 static int link_elf_lookup_set(linker_file_t, const char *, 124 void ***, void ***, int *); 125 static int link_elf_each_function_name(linker_file_t, 126 int (*)(const char *, void *), void *); 127 static void link_elf_reloc_local(linker_file_t); 128 129 static Elf_Addr elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps); 130 131 static kobj_method_t link_elf_methods[] = { 132 KOBJMETHOD(linker_lookup_symbol, link_elf_lookup_symbol), 133 KOBJMETHOD(linker_symbol_values, link_elf_symbol_values), 134 KOBJMETHOD(linker_search_symbol, link_elf_search_symbol), 135 KOBJMETHOD(linker_unload, link_elf_unload_file), 136 KOBJMETHOD(linker_load_file, link_elf_load_file), 137 KOBJMETHOD(linker_link_preload, link_elf_link_preload), 138 KOBJMETHOD(linker_link_preload_finish, link_elf_link_preload_finish), 139 KOBJMETHOD(linker_lookup_set, link_elf_lookup_set), 140 KOBJMETHOD(linker_each_function_name, link_elf_each_function_name), 141 { 0, 0 } 142 }; 143 144 static struct linker_class link_elf_class = { 145 #if ELF_TARG_CLASS == ELFCLASS32 146 "elf32_obj", 147 #else 148 "elf64_obj", 149 #endif 150 link_elf_methods, sizeof(struct elf_file) 151 }; 152 153 static int relocate_file(elf_file_t ef); 154 155 static void 156 link_elf_error(const char *s) 157 { 158 printf("kldload: %s\n", s); 159 } 160 161 static void 162 link_elf_init(void *arg) 163 { 164 165 linker_add_class(&link_elf_class); 166 } 167 168 SYSINIT(link_elf_obj, SI_SUB_KLD, SI_ORDER_SECOND, link_elf_init, 0); 169 170 static int 171 link_elf_link_preload(linker_class_t cls, const char *filename, 172 linker_file_t *result) 173 { 174 Elf_Ehdr *hdr; 175 Elf_Shdr *shdr; 176 Elf_Sym *es; 177 void *modptr, *baseptr, *sizeptr; 178 char *type; 179 elf_file_t ef; 180 linker_file_t lf; 181 Elf_Addr off; 182 int error, i, j, pb, ra, rl, shstrindex, symstrindex, symtabindex; 183 184 /* Look to see if we have the file preloaded */ 185 modptr = preload_search_by_name(filename); 186 if (modptr == NULL) 187 return ENOENT; 188 189 type = (char *)preload_search_info(modptr, MODINFO_TYPE); 190 baseptr = preload_search_info(modptr, MODINFO_ADDR); 191 sizeptr = preload_search_info(modptr, MODINFO_SIZE); 192 hdr = (Elf_Ehdr *)preload_search_info(modptr, MODINFO_METADATA | 193 MODINFOMD_ELFHDR); 194 shdr = (Elf_Shdr *)preload_search_info(modptr, MODINFO_METADATA | 195 MODINFOMD_SHDR); 196 if (type == NULL || (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) 197 " obj module") != 0 && 198 strcmp(type, "elf obj module") != 0)) { 199 return (EFTYPE); 200 } 201 if (baseptr == NULL || sizeptr == NULL || hdr == NULL || 202 shdr == NULL) 203 return (EINVAL); 204 205 lf = linker_make_file(filename, &link_elf_class); 206 if (lf == NULL) 207 return (ENOMEM); 208 209 ef = (elf_file_t)lf; 210 ef->preloaded = 1; 211 ef->address = *(caddr_t *)baseptr; 212 lf->address = *(caddr_t *)baseptr; 213 lf->size = *(size_t *)sizeptr; 214 215 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS || 216 hdr->e_ident[EI_DATA] != ELF_TARG_DATA || 217 hdr->e_ident[EI_VERSION] != EV_CURRENT || 218 hdr->e_version != EV_CURRENT || 219 hdr->e_type != ET_REL || 220 hdr->e_machine != ELF_TARG_MACH) { 221 error = EFTYPE; 222 goto out; 223 } 224 ef->e_shdr = shdr; 225 226 /* Scan the section header for information and table sizing. */ 227 symtabindex = -1; 228 symstrindex = -1; 229 for (i = 0; i < hdr->e_shnum; i++) { 230 switch (shdr[i].sh_type) { 231 case SHT_PROGBITS: 232 case SHT_NOBITS: 233 ef->nprogtab++; 234 break; 235 case SHT_SYMTAB: 236 symtabindex = i; 237 symstrindex = shdr[i].sh_link; 238 break; 239 case SHT_REL: 240 ef->nrel++; 241 break; 242 case SHT_RELA: 243 ef->nrela++; 244 break; 245 } 246 } 247 248 shstrindex = hdr->e_shstrndx; 249 if (ef->nprogtab == 0 || symstrindex < 0 || 250 symstrindex >= hdr->e_shnum || 251 shdr[symstrindex].sh_type != SHT_STRTAB || shstrindex == 0 || 252 shstrindex >= hdr->e_shnum || 253 shdr[shstrindex].sh_type != SHT_STRTAB) { 254 printf("%s: bad/missing section headers\n", filename); 255 error = ENOEXEC; 256 goto out; 257 } 258 259 /* Allocate space for tracking the load chunks */ 260 if (ef->nprogtab != 0) 261 ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab), 262 M_LINKER, M_WAITOK | M_ZERO); 263 if (ef->nrel != 0) 264 ef->reltab = malloc(ef->nrel * sizeof(*ef->reltab), M_LINKER, 265 M_WAITOK | M_ZERO); 266 if (ef->nrela != 0) 267 ef->relatab = malloc(ef->nrela * sizeof(*ef->relatab), M_LINKER, 268 M_WAITOK | M_ZERO); 269 if ((ef->nprogtab != 0 && ef->progtab == NULL) || 270 (ef->nrel != 0 && ef->reltab == NULL) || 271 (ef->nrela != 0 && ef->relatab == NULL)) { 272 error = ENOMEM; 273 goto out; 274 } 275 276 /* XXX, relocate the sh_addr fields saved by the loader. */ 277 off = 0; 278 for (i = 0; i < hdr->e_shnum; i++) { 279 if (shdr[i].sh_addr != 0 && (off == 0 || shdr[i].sh_addr < off)) 280 off = shdr[i].sh_addr; 281 } 282 for (i = 0; i < hdr->e_shnum; i++) { 283 if (shdr[i].sh_addr != 0) 284 shdr[i].sh_addr = shdr[i].sh_addr - off + 285 (Elf_Addr)ef->address; 286 } 287 288 ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym); 289 ef->ddbsymtab = (Elf_Sym *)shdr[symtabindex].sh_addr; 290 ef->ddbstrcnt = shdr[symstrindex].sh_size; 291 ef->ddbstrtab = (char *)shdr[symstrindex].sh_addr; 292 ef->shstrcnt = shdr[shstrindex].sh_size; 293 ef->shstrtab = (char *)shdr[shstrindex].sh_addr; 294 295 /* Now fill out progtab and the relocation tables. */ 296 pb = 0; 297 rl = 0; 298 ra = 0; 299 for (i = 0; i < hdr->e_shnum; i++) { 300 switch (shdr[i].sh_type) { 301 case SHT_PROGBITS: 302 case SHT_NOBITS: 303 ef->progtab[pb].addr = (void *)shdr[i].sh_addr; 304 if (shdr[i].sh_type == SHT_PROGBITS) 305 ef->progtab[pb].name = "<<PROGBITS>>"; 306 else 307 ef->progtab[pb].name = "<<NOBITS>>"; 308 ef->progtab[pb].size = shdr[i].sh_size; 309 ef->progtab[pb].sec = i; 310 if (ef->shstrtab && shdr[i].sh_name != 0) 311 ef->progtab[pb].name = 312 ef->shstrtab + shdr[i].sh_name; 313 314 /* Update all symbol values with the offset. */ 315 for (j = 0; j < ef->ddbsymcnt; j++) { 316 es = &ef->ddbsymtab[j]; 317 if (es->st_shndx != i) 318 continue; 319 es->st_value += (Elf_Addr)ef->progtab[pb].addr; 320 } 321 pb++; 322 break; 323 case SHT_REL: 324 ef->reltab[rl].rel = (Elf_Rel *)shdr[i].sh_addr; 325 ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel); 326 ef->reltab[rl].sec = shdr[i].sh_info; 327 rl++; 328 break; 329 case SHT_RELA: 330 ef->relatab[ra].rela = (Elf_Rela *)shdr[i].sh_addr; 331 ef->relatab[ra].nrela = 332 shdr[i].sh_size / sizeof(Elf_Rela); 333 ef->relatab[ra].sec = shdr[i].sh_info; 334 ra++; 335 break; 336 } 337 } 338 if (pb != ef->nprogtab) 339 panic("lost progbits"); 340 if (rl != ef->nrel) 341 panic("lost rel"); 342 if (ra != ef->nrela) 343 panic("lost rela"); 344 345 /* Local intra-module relocations */ 346 link_elf_reloc_local(lf); 347 348 *result = lf; 349 return (0); 350 351 out: 352 /* preload not done this way */ 353 linker_file_unload(lf, LINKER_UNLOAD_FORCE); 354 return (error); 355 } 356 357 static int 358 link_elf_link_preload_finish(linker_file_t lf) 359 { 360 elf_file_t ef; 361 int error; 362 363 ef = (elf_file_t)lf; 364 error = relocate_file(ef); 365 if (error) 366 return error; 367 368 /* Notify MD code that a module is being loaded. */ 369 error = elf_cpu_load_file(lf); 370 if (error) 371 return (error); 372 373 return (0); 374 } 375 376 static int 377 link_elf_load_file(linker_class_t cls, const char *filename, 378 linker_file_t *result) 379 { 380 struct nameidata nd; 381 struct thread *td = curthread; /* XXX */ 382 Elf_Ehdr *hdr; 383 Elf_Shdr *shdr; 384 Elf_Sym *es; 385 int nbytes, i, j; 386 vm_offset_t mapbase; 387 size_t mapsize; 388 int error = 0; 389 int resid, flags; 390 elf_file_t ef; 391 linker_file_t lf; 392 int symtabindex; 393 int symstrindex; 394 int shstrindex; 395 int nsym; 396 int pb, rl, ra; 397 int alignmask; 398 int vfslocked; 399 400 shdr = NULL; 401 lf = NULL; 402 mapsize = 0; 403 hdr = NULL; 404 405 NDINIT(&nd, LOOKUP, FOLLOW | MPSAFE, UIO_SYSSPACE, filename, td); 406 flags = FREAD; 407 error = vn_open(&nd, &flags, 0, NULL); 408 if (error) 409 return error; 410 vfslocked = NDHASGIANT(&nd); 411 NDFREE(&nd, NDF_ONLY_PNBUF); 412 #ifdef MAC 413 error = mac_check_kld_load(td->td_ucred, nd.ni_vp); 414 if (error) { 415 goto out; 416 } 417 #endif 418 419 /* Read the elf header from the file. */ 420 hdr = malloc(sizeof(*hdr), M_LINKER, M_WAITOK); 421 if (hdr == NULL) { 422 error = ENOMEM; 423 goto out; 424 } 425 error = vn_rdwr(UIO_READ, nd.ni_vp, (void *)hdr, sizeof(*hdr), 0, 426 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 427 &resid, td); 428 if (error) 429 goto out; 430 if (resid != 0){ 431 error = ENOEXEC; 432 goto out; 433 } 434 435 if (!IS_ELF(*hdr)) { 436 error = ENOEXEC; 437 goto out; 438 } 439 440 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS 441 || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) { 442 link_elf_error("Unsupported file layout"); 443 error = ENOEXEC; 444 goto out; 445 } 446 if (hdr->e_ident[EI_VERSION] != EV_CURRENT 447 || hdr->e_version != EV_CURRENT) { 448 link_elf_error("Unsupported file version"); 449 error = ENOEXEC; 450 goto out; 451 } 452 if (hdr->e_type != ET_REL) { 453 link_elf_error("Unsupported file type"); 454 error = ENOEXEC; 455 goto out; 456 } 457 if (hdr->e_machine != ELF_TARG_MACH) { 458 link_elf_error("Unsupported machine"); 459 error = ENOEXEC; 460 goto out; 461 } 462 463 lf = linker_make_file(filename, &link_elf_class); 464 if (!lf) { 465 error = ENOMEM; 466 goto out; 467 } 468 ef = (elf_file_t) lf; 469 ef->nprogtab = 0; 470 ef->e_shdr = 0; 471 ef->nrel = 0; 472 ef->nrela = 0; 473 474 /* Allocate and read in the section header */ 475 nbytes = hdr->e_shnum * hdr->e_shentsize; 476 if (nbytes == 0 || hdr->e_shoff == 0 || 477 hdr->e_shentsize != sizeof(Elf_Shdr)) { 478 error = ENOEXEC; 479 goto out; 480 } 481 shdr = malloc(nbytes, M_LINKER, M_WAITOK); 482 if (shdr == NULL) { 483 error = ENOMEM; 484 goto out; 485 } 486 ef->e_shdr = shdr; 487 error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)shdr, nbytes, hdr->e_shoff, 488 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, &resid, td); 489 if (error) 490 goto out; 491 if (resid) { 492 error = ENOEXEC; 493 goto out; 494 } 495 496 /* Scan the section header for information and table sizing. */ 497 nsym = 0; 498 symtabindex = -1; 499 symstrindex = -1; 500 for (i = 0; i < hdr->e_shnum; i++) { 501 switch (shdr[i].sh_type) { 502 case SHT_PROGBITS: 503 case SHT_NOBITS: 504 ef->nprogtab++; 505 break; 506 case SHT_SYMTAB: 507 nsym++; 508 symtabindex = i; 509 symstrindex = shdr[i].sh_link; 510 break; 511 case SHT_REL: 512 ef->nrel++; 513 break; 514 case SHT_RELA: 515 ef->nrela++; 516 break; 517 case SHT_STRTAB: 518 break; 519 } 520 } 521 if (ef->nprogtab == 0) { 522 link_elf_error("file has no contents"); 523 error = ENOEXEC; 524 goto out; 525 } 526 if (nsym != 1) { 527 /* Only allow one symbol table for now */ 528 link_elf_error("file has no valid symbol table"); 529 error = ENOEXEC; 530 goto out; 531 } 532 if (symstrindex < 0 || symstrindex > hdr->e_shnum || 533 shdr[symstrindex].sh_type != SHT_STRTAB) { 534 link_elf_error("file has invalid symbol strings"); 535 error = ENOEXEC; 536 goto out; 537 } 538 539 /* Allocate space for tracking the load chunks */ 540 if (ef->nprogtab != 0) 541 ef->progtab = malloc(ef->nprogtab * sizeof(*ef->progtab), 542 M_LINKER, M_WAITOK | M_ZERO); 543 if (ef->nrel != 0) 544 ef->reltab = malloc(ef->nrel * sizeof(*ef->reltab), M_LINKER, 545 M_WAITOK | M_ZERO); 546 if (ef->nrela != 0) 547 ef->relatab = malloc(ef->nrela * sizeof(*ef->relatab), M_LINKER, 548 M_WAITOK | M_ZERO); 549 if ((ef->nprogtab != 0 && ef->progtab == NULL) || 550 (ef->nrel != 0 && ef->reltab == NULL) || 551 (ef->nrela != 0 && ef->relatab == NULL)) { 552 error = ENOMEM; 553 goto out; 554 } 555 556 if (symtabindex == -1) 557 panic("lost symbol table index"); 558 /* Allocate space for and load the symbol table */ 559 ef->ddbsymcnt = shdr[symtabindex].sh_size / sizeof(Elf_Sym); 560 ef->ddbsymtab = malloc(shdr[symtabindex].sh_size, M_LINKER, M_WAITOK); 561 if (ef->ddbsymtab == NULL) { 562 error = ENOMEM; 563 goto out; 564 } 565 error = vn_rdwr(UIO_READ, nd.ni_vp, (void *)ef->ddbsymtab, 566 shdr[symtabindex].sh_size, shdr[symtabindex].sh_offset, 567 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 568 &resid, td); 569 if (error) 570 goto out; 571 if (resid != 0){ 572 error = EINVAL; 573 goto out; 574 } 575 576 if (symstrindex == -1) 577 panic("lost symbol string index"); 578 /* Allocate space for and load the symbol strings */ 579 ef->ddbstrcnt = shdr[symstrindex].sh_size; 580 ef->ddbstrtab = malloc(shdr[symstrindex].sh_size, M_LINKER, M_WAITOK); 581 if (ef->ddbstrtab == NULL) { 582 error = ENOMEM; 583 goto out; 584 } 585 error = vn_rdwr(UIO_READ, nd.ni_vp, ef->ddbstrtab, 586 shdr[symstrindex].sh_size, shdr[symstrindex].sh_offset, 587 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 588 &resid, td); 589 if (error) 590 goto out; 591 if (resid != 0){ 592 error = EINVAL; 593 goto out; 594 } 595 596 /* Do we have a string table for the section names? */ 597 shstrindex = -1; 598 if (hdr->e_shstrndx != 0 && 599 shdr[hdr->e_shstrndx].sh_type == SHT_STRTAB) { 600 shstrindex = hdr->e_shstrndx; 601 ef->shstrcnt = shdr[shstrindex].sh_size; 602 ef->shstrtab = malloc(shdr[shstrindex].sh_size, M_LINKER, 603 M_WAITOK); 604 if (ef->shstrtab == NULL) { 605 error = ENOMEM; 606 goto out; 607 } 608 error = vn_rdwr(UIO_READ, nd.ni_vp, ef->shstrtab, 609 shdr[shstrindex].sh_size, shdr[shstrindex].sh_offset, 610 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 611 &resid, td); 612 if (error) 613 goto out; 614 if (resid != 0){ 615 error = EINVAL; 616 goto out; 617 } 618 } 619 620 /* Size up code/data(progbits) and bss(nobits). */ 621 alignmask = 0; 622 for (i = 0; i < hdr->e_shnum; i++) { 623 switch (shdr[i].sh_type) { 624 case SHT_PROGBITS: 625 case SHT_NOBITS: 626 alignmask = shdr[i].sh_addralign - 1; 627 mapsize += alignmask; 628 mapsize &= ~alignmask; 629 mapsize += shdr[i].sh_size; 630 break; 631 } 632 } 633 634 /* 635 * We know how much space we need for the text/data/bss/etc. 636 * This stuff needs to be in a single chunk so that profiling etc 637 * can get the bounds and gdb can associate offsets with modules 638 */ 639 ef->object = vm_object_allocate(OBJT_DEFAULT, 640 round_page(mapsize) >> PAGE_SHIFT); 641 if (ef->object == NULL) { 642 error = ENOMEM; 643 goto out; 644 } 645 ef->address = (caddr_t) vm_map_min(kernel_map); 646 error = vm_map_find(kernel_map, ef->object, 0, &mapbase, 647 round_page(mapsize), TRUE, VM_PROT_ALL, VM_PROT_ALL, FALSE); 648 if (error) { 649 vm_object_deallocate(ef->object); 650 ef->object = 0; 651 goto out; 652 } 653 654 /* Wire the pages */ 655 error = vm_map_wire(kernel_map, mapbase, 656 mapbase + round_page(mapsize), 657 VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES); 658 if (error != KERN_SUCCESS) { 659 error = ENOMEM; 660 goto out; 661 } 662 663 /* Inform the kld system about the situation */ 664 lf->address = ef->address = (caddr_t)mapbase; 665 lf->size = mapsize; 666 667 /* 668 * Now load code/data(progbits), zero bss(nobits), allocate space for 669 * and load relocs 670 */ 671 pb = 0; 672 rl = 0; 673 ra = 0; 674 alignmask = 0; 675 for (i = 0; i < hdr->e_shnum; i++) { 676 switch (shdr[i].sh_type) { 677 case SHT_PROGBITS: 678 case SHT_NOBITS: 679 alignmask = shdr[i].sh_addralign - 1; 680 mapbase += alignmask; 681 mapbase &= ~alignmask; 682 ef->progtab[pb].addr = (void *)(uintptr_t)mapbase; 683 if (shdr[i].sh_type == SHT_PROGBITS) { 684 ef->progtab[pb].name = "<<PROGBITS>>"; 685 error = vn_rdwr(UIO_READ, nd.ni_vp, 686 ef->progtab[pb].addr, 687 shdr[i].sh_size, shdr[i].sh_offset, 688 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, 689 NOCRED, &resid, td); 690 if (error) 691 goto out; 692 if (resid != 0){ 693 error = EINVAL; 694 goto out; 695 } 696 } else { 697 ef->progtab[pb].name = "<<NOBITS>>"; 698 bzero(ef->progtab[pb].addr, shdr[i].sh_size); 699 } 700 ef->progtab[pb].size = shdr[i].sh_size; 701 ef->progtab[pb].sec = i; 702 if (ef->shstrtab && shdr[i].sh_name != 0) 703 ef->progtab[pb].name = 704 ef->shstrtab + shdr[i].sh_name; 705 706 /* Update all symbol values with the offset. */ 707 for (j = 0; j < ef->ddbsymcnt; j++) { 708 es = &ef->ddbsymtab[j]; 709 if (es->st_shndx != i) 710 continue; 711 es->st_value += (Elf_Addr)ef->progtab[pb].addr; 712 } 713 mapbase += shdr[i].sh_size; 714 pb++; 715 break; 716 case SHT_REL: 717 ef->reltab[rl].rel = malloc(shdr[i].sh_size, M_LINKER, 718 M_WAITOK); 719 ef->reltab[rl].nrel = shdr[i].sh_size / sizeof(Elf_Rel); 720 ef->reltab[rl].sec = shdr[i].sh_info; 721 error = vn_rdwr(UIO_READ, nd.ni_vp, 722 (void *)ef->reltab[rl].rel, 723 shdr[i].sh_size, shdr[i].sh_offset, 724 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 725 &resid, td); 726 if (error) 727 goto out; 728 if (resid != 0){ 729 error = EINVAL; 730 goto out; 731 } 732 rl++; 733 break; 734 case SHT_RELA: 735 ef->relatab[ra].rela = malloc(shdr[i].sh_size, M_LINKER, 736 M_WAITOK); 737 ef->relatab[ra].nrela = 738 shdr[i].sh_size / sizeof(Elf_Rela); 739 ef->relatab[ra].sec = shdr[i].sh_info; 740 error = vn_rdwr(UIO_READ, nd.ni_vp, 741 (void *)ef->relatab[ra].rela, 742 shdr[i].sh_size, shdr[i].sh_offset, 743 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 744 &resid, td); 745 if (error) 746 goto out; 747 if (resid != 0){ 748 error = EINVAL; 749 goto out; 750 } 751 ra++; 752 break; 753 } 754 } 755 if (pb != ef->nprogtab) 756 panic("lost progbits"); 757 if (rl != ef->nrel) 758 panic("lost rel"); 759 if (ra != ef->nrela) 760 panic("lost rela"); 761 if (mapbase != (vm_offset_t)ef->address + mapsize) 762 panic("mapbase 0x%lx != address %p + mapsize 0x%lx (0x%lx)\n", 763 mapbase, ef->address, mapsize, 764 (vm_offset_t)ef->address + mapsize); 765 766 /* Local intra-module relocations */ 767 link_elf_reloc_local(lf); 768 769 /* Pull in dependencies */ 770 error = linker_load_dependencies(lf); 771 if (error) 772 goto out; 773 774 /* External relocations */ 775 error = relocate_file(ef); 776 if (error) 777 goto out; 778 779 /* Notify MD code that a module is being loaded. */ 780 error = elf_cpu_load_file(lf); 781 if (error) 782 goto out; 783 784 *result = lf; 785 786 out: 787 if (error && lf) 788 linker_file_unload(lf, LINKER_UNLOAD_FORCE); 789 if (hdr) 790 free(hdr, M_LINKER); 791 VOP_UNLOCK(nd.ni_vp, 0, td); 792 vn_close(nd.ni_vp, FREAD, td->td_ucred, td); 793 VFS_UNLOCK_GIANT(vfslocked); 794 795 return error; 796 } 797 798 static void 799 link_elf_unload_file(linker_file_t file) 800 { 801 elf_file_t ef = (elf_file_t) file; 802 int i; 803 804 /* Notify MD code that a module is being unloaded. */ 805 elf_cpu_unload_file(file); 806 807 if (ef->preloaded) { 808 if (ef->reltab) 809 free(ef->reltab, M_LINKER); 810 if (ef->relatab) 811 free(ef->relatab, M_LINKER); 812 if (ef->progtab) 813 free(ef->progtab, M_LINKER); 814 if (file->filename != NULL) 815 preload_delete_name(file->filename); 816 /* XXX reclaim module memory? */ 817 return; 818 } 819 820 for (i = 0; i < ef->nrel; i++) 821 if (ef->reltab[i].rel) 822 free(ef->reltab[i].rel, M_LINKER); 823 for (i = 0; i < ef->nrela; i++) 824 if (ef->relatab[i].rela) 825 free(ef->relatab[i].rela, M_LINKER); 826 if (ef->reltab) 827 free(ef->reltab, M_LINKER); 828 if (ef->relatab) 829 free(ef->relatab, M_LINKER); 830 if (ef->progtab) 831 free(ef->progtab, M_LINKER); 832 833 if (ef->object) { 834 vm_map_remove(kernel_map, (vm_offset_t) ef->address, 835 (vm_offset_t) ef->address + 836 (ef->object->size << PAGE_SHIFT)); 837 } 838 if (ef->e_shdr) 839 free(ef->e_shdr, M_LINKER); 840 if (ef->ddbsymtab) 841 free(ef->ddbsymtab, M_LINKER); 842 if (ef->ddbstrtab) 843 free(ef->ddbstrtab, M_LINKER); 844 if (ef->shstrtab) 845 free(ef->shstrtab, M_LINKER); 846 } 847 848 static const char * 849 symbol_name(elf_file_t ef, Elf_Size r_info) 850 { 851 const Elf_Sym *ref; 852 853 if (ELF_R_SYM(r_info)) { 854 ref = ef->ddbsymtab + ELF_R_SYM(r_info); 855 return ef->ddbstrtab + ref->st_name; 856 } else 857 return NULL; 858 } 859 860 static Elf_Addr 861 findbase(elf_file_t ef, int sec) 862 { 863 int i; 864 Elf_Addr base = 0; 865 866 for (i = 0; i < ef->nprogtab; i++) { 867 if (sec == ef->progtab[i].sec) { 868 base = (Elf_Addr)ef->progtab[i].addr; 869 break; 870 } 871 } 872 return base; 873 } 874 875 static int 876 relocate_file(elf_file_t ef) 877 { 878 const Elf_Rel *rellim; 879 const Elf_Rel *rel; 880 const Elf_Rela *relalim; 881 const Elf_Rela *rela; 882 const char *symname; 883 const Elf_Sym *sym; 884 int i; 885 Elf_Size symidx; 886 Elf_Addr base; 887 888 889 /* Perform relocations without addend if there are any: */ 890 for (i = 0; i < ef->nrel; i++) { 891 rel = ef->reltab[i].rel; 892 if (rel == NULL) 893 panic("lost a reltab!"); 894 rellim = rel + ef->reltab[i].nrel; 895 base = findbase(ef, ef->reltab[i].sec); 896 if (base == 0) 897 panic("lost base for reltab"); 898 for ( ; rel < rellim; rel++) { 899 symidx = ELF_R_SYM(rel->r_info); 900 if (symidx >= ef->ddbsymcnt) 901 continue; 902 sym = ef->ddbsymtab + symidx; 903 /* Local relocs are already done */ 904 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) 905 continue; 906 if (elf_reloc(&ef->lf, base, rel, ELF_RELOC_REL, 907 elf_obj_lookup)) { 908 symname = symbol_name(ef, rel->r_info); 909 printf("link_elf_obj: symbol %s undefined\n", 910 symname); 911 return ENOENT; 912 } 913 } 914 } 915 916 /* Perform relocations with addend if there are any: */ 917 for (i = 0; i < ef->nrela; i++) { 918 rela = ef->relatab[i].rela; 919 if (rela == NULL) 920 panic("lost a relatab!"); 921 relalim = rela + ef->relatab[i].nrela; 922 base = findbase(ef, ef->relatab[i].sec); 923 if (base == 0) 924 panic("lost base for relatab"); 925 for ( ; rela < relalim; rela++) { 926 symidx = ELF_R_SYM(rela->r_info); 927 if (symidx >= ef->ddbsymcnt) 928 continue; 929 sym = ef->ddbsymtab + symidx; 930 /* Local relocs are already done */ 931 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) 932 continue; 933 if (elf_reloc(&ef->lf, base, rela, ELF_RELOC_RELA, 934 elf_obj_lookup)) { 935 symname = symbol_name(ef, rela->r_info); 936 printf("link_elf_obj: symbol %s undefined\n", 937 symname); 938 return ENOENT; 939 } 940 } 941 } 942 943 return 0; 944 } 945 946 static int 947 link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym) 948 { 949 elf_file_t ef = (elf_file_t) lf; 950 const Elf_Sym *symp; 951 const char *strp; 952 int i; 953 954 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 955 strp = ef->ddbstrtab + symp->st_name; 956 if (symp->st_shndx != SHN_UNDEF && strcmp(name, strp) == 0) { 957 *sym = (c_linker_sym_t) symp; 958 return 0; 959 } 960 } 961 return ENOENT; 962 } 963 964 static int 965 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, 966 linker_symval_t *symval) 967 { 968 elf_file_t ef = (elf_file_t) lf; 969 const Elf_Sym *es = (const Elf_Sym*) sym; 970 971 if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) { 972 symval->name = ef->ddbstrtab + es->st_name; 973 symval->value = (caddr_t)es->st_value; 974 symval->size = es->st_size; 975 return 0; 976 } 977 return ENOENT; 978 } 979 980 static int 981 link_elf_search_symbol(linker_file_t lf, caddr_t value, 982 c_linker_sym_t *sym, long *diffp) 983 { 984 elf_file_t ef = (elf_file_t) lf; 985 u_long off = (uintptr_t) (void *) value; 986 u_long diff = off; 987 u_long st_value; 988 const Elf_Sym *es; 989 const Elf_Sym *best = 0; 990 int i; 991 992 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) { 993 if (es->st_name == 0) 994 continue; 995 st_value = es->st_value; 996 if (off >= st_value) { 997 if (off - st_value < diff) { 998 diff = off - st_value; 999 best = es; 1000 if (diff == 0) 1001 break; 1002 } else if (off - st_value == diff) { 1003 best = es; 1004 } 1005 } 1006 } 1007 if (best == 0) 1008 *diffp = off; 1009 else 1010 *diffp = diff; 1011 *sym = (c_linker_sym_t) best; 1012 1013 return 0; 1014 } 1015 1016 /* 1017 * Look up a linker set on an ELF system. 1018 */ 1019 static int 1020 link_elf_lookup_set(linker_file_t lf, const char *name, 1021 void ***startp, void ***stopp, int *countp) 1022 { 1023 elf_file_t ef = (elf_file_t)lf; 1024 void **start, **stop; 1025 int i, count; 1026 1027 /* Relative to section number */ 1028 for (i = 0; i < ef->nprogtab; i++) { 1029 if ((strncmp(ef->progtab[i].name, "set_", 4) == 0) && 1030 strcmp(ef->progtab[i].name + 4, name) == 0) { 1031 start = (void **)ef->progtab[i].addr; 1032 stop = (void **)((char *)ef->progtab[i].addr + 1033 ef->progtab[i].size); 1034 count = stop - start; 1035 if (startp) 1036 *startp = start; 1037 if (stopp) 1038 *stopp = stop; 1039 if (countp) 1040 *countp = count; 1041 return (0); 1042 } 1043 } 1044 return (ESRCH); 1045 } 1046 1047 static int 1048 link_elf_each_function_name(linker_file_t file, 1049 int (*callback)(const char *, void *), void *opaque) 1050 { 1051 elf_file_t ef = (elf_file_t)file; 1052 const Elf_Sym *symp; 1053 int i, error; 1054 1055 /* Exhaustive search */ 1056 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1057 if (symp->st_value != 0 && 1058 ELF_ST_TYPE(symp->st_info) == STT_FUNC) { 1059 error = callback(ef->ddbstrtab + symp->st_name, opaque); 1060 if (error) 1061 return (error); 1062 } 1063 } 1064 return (0); 1065 } 1066 1067 /* 1068 * Symbol lookup function that can be used when the symbol index is known (ie 1069 * in relocations). It uses the symbol index instead of doing a fully fledged 1070 * hash table based lookup when such is valid. For example for local symbols. 1071 * This is not only more efficient, it's also more correct. It's not always 1072 * the case that the symbol can be found through the hash table. 1073 */ 1074 static Elf_Addr 1075 elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps) 1076 { 1077 elf_file_t ef = (elf_file_t)lf; 1078 const Elf_Sym *sym; 1079 const char *symbol; 1080 Elf_Addr ret; 1081 1082 /* Don't even try to lookup the symbol if the index is bogus. */ 1083 if (symidx >= ef->ddbsymcnt) 1084 return (0); 1085 1086 sym = ef->ddbsymtab + symidx; 1087 1088 /* Quick answer if there is a definition included. */ 1089 if (sym->st_shndx != SHN_UNDEF) 1090 return (sym->st_value); 1091 1092 /* If we get here, then it is undefined and needs a lookup. */ 1093 switch (ELF_ST_BIND(sym->st_info)) { 1094 case STB_LOCAL: 1095 /* Local, but undefined? huh? */ 1096 return (0); 1097 1098 case STB_GLOBAL: 1099 /* Relative to Data or Function name */ 1100 symbol = ef->ddbstrtab + sym->st_name; 1101 1102 /* Force a lookup failure if the symbol name is bogus. */ 1103 if (*symbol == 0) 1104 return (0); 1105 ret = ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps)); 1106 return ret; 1107 1108 case STB_WEAK: 1109 printf("link_elf_obj: Weak symbols not supported\n"); 1110 return (0); 1111 1112 default: 1113 return (0); 1114 } 1115 } 1116 1117 static void 1118 link_elf_fix_link_set(elf_file_t ef) 1119 { 1120 static const char startn[] = "__start_"; 1121 static const char stopn[] = "__stop_"; 1122 Elf_Sym *sym; 1123 const char *sym_name, *linkset_name; 1124 Elf_Addr startp, stopp; 1125 Elf_Size symidx; 1126 int start, i; 1127 1128 startp = stopp = 0; 1129 for (symidx = 1 /* zero entry is special */; 1130 symidx < ef->ddbsymcnt; symidx++) { 1131 sym = ef->ddbsymtab + symidx; 1132 if (sym->st_shndx != SHN_UNDEF) 1133 continue; 1134 1135 sym_name = ef->ddbstrtab + sym->st_name; 1136 if (strncmp(sym_name, startn, sizeof(startn) - 1) == 0) { 1137 start = 1; 1138 linkset_name = sym_name + sizeof(startn) - 1; 1139 } 1140 else if (strncmp(sym_name, stopn, sizeof(stopn) - 1) == 0) { 1141 start = 0; 1142 linkset_name = sym_name + sizeof(stopn) - 1; 1143 } 1144 else 1145 continue; 1146 1147 for (i = 0; i < ef->nprogtab; i++) { 1148 if (strcmp(ef->progtab[i].name, linkset_name) == 0) { 1149 startp = (Elf_Addr)ef->progtab[i].addr; 1150 stopp = (Elf_Addr)(startp + ef->progtab[i].size); 1151 break; 1152 } 1153 } 1154 if (i == ef->nprogtab) 1155 continue; 1156 1157 sym->st_value = start ? startp : stopp; 1158 sym->st_shndx = i; 1159 } 1160 } 1161 1162 static void 1163 link_elf_reloc_local(linker_file_t lf) 1164 { 1165 elf_file_t ef = (elf_file_t)lf; 1166 const Elf_Rel *rellim; 1167 const Elf_Rel *rel; 1168 const Elf_Rela *relalim; 1169 const Elf_Rela *rela; 1170 const Elf_Sym *sym; 1171 Elf_Addr base; 1172 int i; 1173 Elf_Size symidx; 1174 1175 link_elf_fix_link_set(ef); 1176 1177 /* Perform relocations without addend if there are any: */ 1178 for (i = 0; i < ef->nrel; i++) { 1179 rel = ef->reltab[i].rel; 1180 if (rel == NULL) 1181 panic("lost a reltab!"); 1182 rellim = rel + ef->reltab[i].nrel; 1183 base = findbase(ef, ef->reltab[i].sec); 1184 if (base == 0) 1185 panic("lost base for reltab"); 1186 for ( ; rel < rellim; rel++) { 1187 symidx = ELF_R_SYM(rel->r_info); 1188 if (symidx >= ef->ddbsymcnt) 1189 continue; 1190 sym = ef->ddbsymtab + symidx; 1191 /* Only do local relocs */ 1192 if (ELF_ST_BIND(sym->st_info) != STB_LOCAL) 1193 continue; 1194 elf_reloc_local(lf, base, rel, ELF_RELOC_REL, 1195 elf_obj_lookup); 1196 } 1197 } 1198 1199 /* Perform relocations with addend if there are any: */ 1200 for (i = 0; i < ef->nrela; i++) { 1201 rela = ef->relatab[i].rela; 1202 if (rela == NULL) 1203 panic("lost a relatab!"); 1204 relalim = rela + ef->relatab[i].nrela; 1205 base = findbase(ef, ef->relatab[i].sec); 1206 if (base == 0) 1207 panic("lost base for relatab"); 1208 for ( ; rela < relalim; rela++) { 1209 symidx = ELF_R_SYM(rela->r_info); 1210 if (symidx >= ef->ddbsymcnt) 1211 continue; 1212 sym = ef->ddbsymtab + symidx; 1213 /* Only do local relocs */ 1214 if (ELF_ST_BIND(sym->st_info) != STB_LOCAL) 1215 continue; 1216 elf_reloc_local(lf, base, rela, ELF_RELOC_RELA, 1217 elf_obj_lookup); 1218 } 1219 } 1220 }
Cache object: b68cb24db1e93ada20ffcc09032e4c31
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