elf_update.c revision 4484
1/*- 2 * Copyright (c) 2006 Joseph Koshy 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 */ 26 27 28#include <sys/mman.h> 29#include <sys/param.h> 30 31#include <assert.h> 32#include <errno.h> 33#include "gelf.h" 34#include "libelf.h" 35#include <stdlib.h> 36#include <string.h> 37#include <unistd.h> 38 39#include "_libelf.h" 40 41/* 42 * Update the internal data structures associated with an ELF object. 43 * Returns the size in bytes the ELF object would occupy in its file 44 * representation. 45 * 46 * After a successful call to this function, the following structures 47 * are updated: 48 * 49 * - The ELF header is updated. 50 * - All sections are sorted in order of ascending addresses and their 51 * section header table entries updated. An error is signalled 52 * if an overlap was detected among sections. 53 * - All data descriptors associated with a section are sorted in order 54 * of ascending addresses. Overlaps, if detected, are signalled as 55 * errors. Other sanity checks for alignments, section types etc. are 56 * made. 57 * 58 * After a resync_elf() successfully returns, the ELF descriptor is 59 * ready for being handed over to _libelf_write_elf(). 60 * 61 * File alignments: 62 * PHDR - Addr 63 * SHDR - Addr 64 * 65 * XXX: how do we handle 'flags'. 66 */ 67 68/* 69 * Compute the extents of a section, by looking at the. 70 */ 71static int 72_libelf_compute_section_extents(Elf *e, Elf_Scn *s, off_t *rc) 73{ 74 int ec; 75 Elf_Data *d, *td; 76 unsigned int elftype; 77 uint32_t sh_type; 78 uint64_t d_align; 79 uint64_t sh_align, sh_entsize, sh_offset, sh_size; 80 uint64_t scn_size, scn_alignment; 81 82 /* 83 * We need to recompute library private data structures if one 84 * or more of the following is true: 85 * - The underlying Shdr structure has been marked `dirty'. Significant 86 * fields include: `sh_offset', `sh_type', `sh_size', `sh_addralign'. 87 * - The Elf_Data structures part of this section have been marked 88 * `dirty'. Affected members include `d_align', `d_offset', `d_type', 89 * and `d_size'. 90 * - The section as a whole is `dirty', e.g., it has been allocated 91 * using elf_newscn(), or if a new Elf_Data structure was added using 92 * elf_newdata(). 93 * 94 * Each of these conditions would result in the ELF_F_DIRTY bit being 95 * set on the section descriptor's `s_flags' field. 96 */ 97 98 ec = e->e_class; 99 100 if (ec == ELFCLASS32) { 101 sh_type = s->s_shdr.s_shdr32.sh_type; 102 sh_align = (uint64_t) s->s_shdr.s_shdr32.sh_addralign; 103 sh_entsize = (uint64_t) s->s_shdr.s_shdr32.sh_entsize; 104 sh_offset = (uint64_t) s->s_shdr.s_shdr32.sh_offset; 105 sh_size = (uint64_t) s->s_shdr.s_shdr32.sh_size; 106 } else { 107 sh_type = s->s_shdr.s_shdr64.sh_type; 108 sh_align = s->s_shdr.s_shdr64.sh_addralign; 109 sh_entsize = s->s_shdr.s_shdr64.sh_entsize; 110 sh_offset = s->s_shdr.s_shdr64.sh_offset; 111 sh_size = s->s_shdr.s_shdr64.sh_size; 112 } 113 114 if (sh_type == SHT_NULL || sh_type == SHT_NOBITS) 115 return (1); 116 117 if ((s->s_flags & ELF_F_DIRTY) == 0) { 118 if ((size_t) *rc < sh_offset + sh_size) 119 *rc = sh_offset + sh_size; 120 return (1); 121 } 122 123 elftype = _libelf_xlate_shtype(sh_type); 124 if (elftype > ELF_T_LAST) { 125 LIBELF_SET_ERROR(SECTION, 0); 126 return (0); 127 } 128 129 /* 130 * Compute the extent of the data descriptors associated with 131 * this section. 132 */ 133 scn_alignment = 0; 134 if (sh_align == 0) 135 sh_align = _libelf_falign(elftype, ec); 136 137 /* Compute the section alignment. */ 138 STAILQ_FOREACH(d, &s->s_data, d_next) { 139 if (d->d_type != elftype) { 140 LIBELF_SET_ERROR(DATA, 0); 141 return (0); 142 } 143 if (d->d_version != e->e_version) { 144 LIBELF_SET_ERROR(VERSION, 0); 145 return (0); 146 } 147 if ((d_align = d->d_align) % sh_align) { 148 LIBELF_SET_ERROR(LAYOUT, 0); 149 return (0); 150 } 151 if (d_align == 0 || (d_align & (d_align - 1))) { 152 LIBELF_SET_ERROR(DATA, 0); 153 return (0); 154 } 155 if (d_align > scn_alignment) 156 scn_alignment = d_align; 157 } 158 159 scn_size = 0L; 160 161 STAILQ_FOREACH_SAFE(d, &s->s_data, d_next, td) { 162 if (e->e_flags & ELF_F_LAYOUT) { 163 if ((uint64_t) d->d_off + d->d_size > scn_size) 164 scn_size = d->d_off + d->d_size; 165 } else { 166 scn_size = roundup(scn_size, scn_alignment); 167 d->d_off = scn_size; 168 scn_size += d->d_size; 169 } 170 } 171 172 /* 173 * If the application is requesting full control over the layout 174 * of the section, check its values for sanity. 175 */ 176 if (e->e_flags & ELF_F_LAYOUT) { 177 if (scn_alignment > sh_align || sh_offset % sh_align || 178 sh_size < scn_size) { 179 LIBELF_SET_ERROR(LAYOUT, 0); 180 return (0); 181 } 182 } else { 183 /* 184 * Otherwise compute the values in the section header. 185 */ 186 187 if (scn_alignment > sh_align) 188 sh_align = scn_alignment; 189 190 /* 191 * If the section entry size is zero, try and fill in an 192 * appropriate entry size. Per the elf(5) manual page 193 * sections without fixed-size entries should have their 194 * 'sh_entsize' field set to zero. 195 */ 196 if (sh_entsize == 0 && 197 (sh_entsize = _libelf_fsize(elftype, ec, e->e_version, 198 (size_t) 1)) == 1) 199 sh_entsize = 0; 200 201 sh_size = scn_size; 202 sh_offset = roundup(*rc, sh_align); 203 204 if (ec == ELFCLASS32) { 205 s->s_shdr.s_shdr32.sh_addralign = (uint32_t) sh_align; 206 s->s_shdr.s_shdr32.sh_entsize = (uint32_t) sh_entsize; 207 s->s_shdr.s_shdr32.sh_offset = (uint32_t) sh_offset; 208 s->s_shdr.s_shdr32.sh_size = (uint32_t) sh_size; 209 } else { 210 s->s_shdr.s_shdr64.sh_addralign = sh_align; 211 s->s_shdr.s_shdr64.sh_entsize = sh_entsize; 212 s->s_shdr.s_shdr64.sh_offset = sh_offset; 213 s->s_shdr.s_shdr64.sh_size = sh_size; 214 } 215 } 216 217 if ((size_t) *rc < sh_offset + sh_size) 218 *rc = sh_offset + sh_size; 219 220 s->s_size = sh_size; 221 s->s_offset = sh_offset; 222 return (1); 223} 224 225 226/* 227 * Insert a section in ascending order in the list 228 */ 229 230static int 231_libelf_insert_section(Elf *e, Elf_Scn *s) 232{ 233 Elf_Scn *t, *prevt; 234 uint64_t smax, smin, tmax, tmin; 235 236 smin = s->s_offset; 237 smax = smin + s->s_size; 238 239 prevt = NULL; 240 STAILQ_FOREACH(t, &e->e_u.e_elf.e_scn, s_next) { 241 tmin = t->s_offset; 242 tmax = tmin + t->s_size; 243 244 /* check if there is an overlap */ 245 if (tmax < smin) { 246 prevt = t; 247 continue; 248 } else if (smax < tmin) 249 break; 250 else { 251 LIBELF_SET_ERROR(LAYOUT, 0); 252 return (0); 253 } 254 } 255 256 if (prevt) 257 STAILQ_INSERT_AFTER(&e->e_u.e_elf.e_scn, prevt, s, s_next); 258 else 259 STAILQ_INSERT_HEAD(&e->e_u.e_elf.e_scn, s, s_next); 260 return (1); 261} 262 263static off_t 264_libelf_resync_sections(Elf *e, off_t rc) 265{ 266 int ec; 267 off_t nrc; 268 size_t sh_type; 269 Elf_Scn *s, *ts; 270 271 ec = e->e_class; 272 273 /* 274 * Make a pass through sections, computing the extent of each 275 * section. Order in increasing order of addresses. 276 */ 277 278 nrc = rc; 279 STAILQ_FOREACH(s, &e->e_u.e_elf.e_scn, s_next) 280 if (_libelf_compute_section_extents(e, s, &nrc) == 0) 281 return ((off_t) -1); 282 283 STAILQ_FOREACH_SAFE(s, &e->e_u.e_elf.e_scn, s_next, ts) { 284 if (ec == ELFCLASS32) 285 sh_type = s->s_shdr.s_shdr32.sh_type; 286 else 287 sh_type = s->s_shdr.s_shdr64.sh_type; 288 289 /* XXX Do we need the 'size' field of an SHT_NOBITS section */ 290 if (sh_type == SHT_NOBITS || sh_type == SHT_NULL) 291 continue; 292 293 if (s->s_offset < (uint64_t) rc) { 294 if (s->s_offset + s->s_size < (uint64_t) rc) { 295 /* 296 * Try insert this section in the 297 * correct place in the list, 298 * detecting overlaps if any. 299 */ 300 STAILQ_REMOVE(&e->e_u.e_elf.e_scn, s, _Elf_Scn, 301 s_next); 302 if (_libelf_insert_section(e, s) == 0) 303 return ((off_t) -1); 304 } else { 305 LIBELF_SET_ERROR(LAYOUT, 0); 306 return ((off_t) -1); 307 } 308 } else 309 rc = s->s_offset + s->s_size; 310 } 311 312 assert(nrc == rc); 313 314 return (rc); 315} 316 317static off_t 318_libelf_resync_elf(Elf *e) 319{ 320 int ec, eh_class, eh_type; 321 unsigned int eh_byteorder, eh_version; 322 size_t align, fsz; 323 size_t phnum, shnum; 324 off_t rc, phoff, shoff; 325 void *ehdr; 326 Elf32_Ehdr *eh32; 327 Elf64_Ehdr *eh64; 328 329 rc = 0; 330 331 ec = e->e_class; 332 333 assert(ec == ELFCLASS32 || ec == ELFCLASS64); 334 335 /* 336 * Prepare the EHDR. 337 */ 338 if ((ehdr = _libelf_ehdr(e, ec, 0)) == NULL) 339 return ((off_t) -1); 340 341 eh32 = ehdr; 342 eh64 = ehdr; 343 344 if (ec == ELFCLASS32) { 345 eh_byteorder = eh32->e_ident[EI_DATA]; 346 eh_class = eh32->e_ident[EI_CLASS]; 347 phoff = (uint64_t) eh32->e_phoff; 348 shoff = (uint64_t) eh32->e_shoff; 349 eh_type = eh32->e_type; 350 eh_version = eh32->e_version; 351 } else { 352 eh_byteorder = eh64->e_ident[EI_DATA]; 353 eh_class = eh64->e_ident[EI_CLASS]; 354 phoff = eh64->e_phoff; 355 shoff = eh64->e_shoff; 356 eh_type = eh64->e_type; 357 eh_version = eh64->e_version; 358 } 359 360 if (eh_version == EV_NONE) 361 eh_version = EV_CURRENT; 362 363 if (eh_version != e->e_version) { /* always EV_CURRENT */ 364 LIBELF_SET_ERROR(VERSION, 0); 365 return ((off_t) -1); 366 } 367 368 if (eh_class != e->e_class) { 369 LIBELF_SET_ERROR(CLASS, 0); 370 return ((off_t) -1); 371 } 372 373 if (e->e_cmd != ELF_C_WRITE && eh_byteorder != e->e_byteorder) { 374 LIBELF_SET_ERROR(HEADER, 0); 375 return ((off_t) -1); 376 } 377 378 shnum = e->e_u.e_elf.e_nscn; 379 phnum = e->e_u.e_elf.e_nphdr; 380 381 e->e_byteorder = eh_byteorder; 382 383#define INITIALIZE_EHDR(E,EC,V) do { \ 384 (E)->e_ident[EI_MAG0] = ELFMAG0; \ 385 (E)->e_ident[EI_MAG1] = ELFMAG1; \ 386 (E)->e_ident[EI_MAG2] = ELFMAG2; \ 387 (E)->e_ident[EI_MAG3] = ELFMAG3; \ 388 (E)->e_ident[EI_CLASS] = (EC); \ 389 (E)->e_ident[EI_VERSION] = (V); \ 390 (E)->e_ehsize = _libelf_fsize(ELF_T_EHDR, (EC), (V), \ 391 (size_t) 1); \ 392 (E)->e_phentsize = _libelf_fsize(ELF_T_PHDR, (EC), (V), \ 393 (size_t) 1); \ 394 (E)->e_shentsize = _libelf_fsize(ELF_T_SHDR, (EC), (V), \ 395 (size_t) 1); \ 396 } while (0) 397 398 if (ec == ELFCLASS32) 399 INITIALIZE_EHDR(eh32, ec, eh_version); 400 else 401 INITIALIZE_EHDR(eh64, ec, eh_version); 402 403 (void) elf_flagehdr(e, ELF_C_SET, ELF_F_DIRTY); 404 405 rc += _libelf_fsize(ELF_T_EHDR, ec, eh_version, (size_t) 1); 406 407 /* 408 * Compute the layout the program header table, if one is 409 * present. The program header table needs to be aligned to a 410 * `natural' boundary. 411 */ 412 if (phnum) { 413 fsz = _libelf_fsize(ELF_T_PHDR, ec, eh_version, phnum); 414 align = _libelf_falign(ELF_T_PHDR, ec); 415 416 if (e->e_flags & ELF_F_LAYOUT) { 417 /* 418 * Check offsets for sanity. 419 */ 420 if (rc > phoff) { 421 LIBELF_SET_ERROR(HEADER, 0); 422 return ((off_t) -1); 423 } 424 425 if (phoff % align) { 426 LIBELF_SET_ERROR(LAYOUT, 0); 427 return ((off_t) -1); 428 } 429 430 } else 431 phoff = roundup(rc, align); 432 433 rc = phoff + fsz; 434 } else 435 phoff = 0; 436 437 /* 438 * Compute the layout of the sections associated with the 439 * file. 440 */ 441 442 if ((rc = _libelf_resync_sections(e, rc)) < 0) 443 return ((off_t) -1); 444 445 /* 446 * Compute the space taken up by the section header table, if 447 * one is needed. 448 */ 449 if (shnum) { 450 fsz = _libelf_fsize(ELF_T_SHDR, ec, eh_version, (size_t) 1); 451 align = _libelf_falign(ELF_T_SHDR, ec); 452 453 if (e->e_flags & ELF_F_LAYOUT) { 454 if (rc > shoff) { 455 LIBELF_SET_ERROR(HEADER, 0); 456 return ((off_t) -1); 457 } 458 459 if (shoff % align) { 460 LIBELF_SET_ERROR(LAYOUT, 0); 461 return ((off_t) -1); 462 } 463 } else 464 shoff = roundup(rc, align); 465 466 rc = shoff + fsz * shnum; 467 } else 468 shoff = 0; 469 470 /* 471 * Set the fields of the Executable Header that could potentially use 472 * extended numbering. 473 */ 474 _libelf_setphnum(e, ehdr, ec, phnum); 475 _libelf_setshnum(e, ehdr, ec, shnum); 476 477 /* 478 * Update the `e_phoff' and `e_shoff' fields if the library is 479 * doing the layout. 480 */ 481 if ((e->e_flags & ELF_F_LAYOUT) == 0) { 482 if (ec == ELFCLASS32) { 483 eh32->e_phoff = (uint32_t) phoff; 484 eh32->e_shoff = (uint32_t) shoff; 485 } else { 486 eh64->e_phoff = (uint64_t) phoff; 487 eh64->e_shoff = (uint64_t) shoff; 488 } 489 } 490 491 return (rc); 492} 493 494/* 495 * Write out the contents of a section. 496 */ 497 498static off_t 499_libelf_write_scn(Elf *e, char *nf, Elf_Scn *s, off_t rc) 500{ 501 int ec; 502 size_t fsz, msz, nobjects; 503 uint32_t sh_type; 504 uint64_t sh_off; 505 int elftype; 506 Elf_Data *d, dst; 507 508 if ((ec = e->e_class) == ELFCLASS32) 509 sh_type = s->s_shdr.s_shdr32.sh_type; 510 else 511 sh_type = s->s_shdr.s_shdr64.sh_type; 512 513 /* 514 * Ignore sections that do not allocate space in the file. 515 */ 516 if (sh_type == SHT_NOBITS || sh_type == SHT_NULL) 517 return (rc); 518 519 520 elftype = _libelf_xlate_shtype(sh_type); 521 assert(elftype >= ELF_T_FIRST && elftype <= ELF_T_LAST); 522 523 msz = _libelf_msize(elftype, ec, e->e_version); 524 525 sh_off = s->s_offset; 526 assert(sh_off % _libelf_falign(elftype, ec) == 0); 527 528 /* 529 * If the section has a `rawdata' descriptor, and the section 530 * contents have not been modified, use its contents directly. 531 * The `s_rawoff' member contains the offset into the original 532 * file, while `s_offset' contains its new location in the 533 * destination. 534 */ 535 536 if (STAILQ_EMPTY(&s->s_data)) { 537 538 if ((d = elf_rawdata(s, NULL)) == NULL) 539 return ((off_t) -1); 540 541 STAILQ_FOREACH(d, &s->s_rawdata, d_next) { 542 if ((uint64_t) rc < sh_off + d->d_off) 543 (void) memset(nf + rc, 544 LIBELF_PRIVATE(fillchar), sh_off + 545 d->d_off - rc); 546 rc = sh_off + d->d_off; 547 548 assert(d->d_buf != NULL); 549 assert(d->d_type == ELF_T_BYTE); 550 assert(d->d_version == e->e_version); 551 552 (void) memcpy(nf + rc, 553 e->e_rawfile + s->s_rawoff + d->d_off, d->d_size); 554 555 rc += d->d_size; 556 } 557 558 return (rc); 559 } 560 561 /* 562 * Iterate over the set of data descriptors for this section. 563 * The prior call to _libelf_resync_elf() would have setup the 564 * descriptors for this step. 565 */ 566 567 dst.d_version = e->e_version; 568 569 STAILQ_FOREACH(d, &s->s_data, d_next) { 570 571 if ((uint64_t) rc < sh_off + d->d_off) 572 (void) memset(nf + rc, 573 LIBELF_PRIVATE(fillchar), sh_off + d->d_off - rc); 574 575 rc = sh_off + d->d_off; 576 577 assert(d->d_buf != NULL); 578 assert(d->d_type == (Elf_Type) elftype); 579 assert(d->d_version == e->e_version); 580 assert(d->d_size % msz == 0); 581 582 nobjects = d->d_size / msz; 583 584 fsz = _libelf_fsize(elftype, ec, e->e_version, nobjects); 585 586 dst.d_buf = nf + rc; 587 dst.d_size = fsz; 588 589 if (_libelf_xlate(&dst, d, e->e_byteorder, ec, ELF_TOFILE) == 590 NULL) 591 return ((off_t) -1); 592 593 rc += fsz; 594 } 595 596 return ((off_t) rc); 597} 598 599/* 600 * Write out the file image. 601 * 602 * The original file could have been mapped in with an ELF_C_RDWR 603 * command and the application could have added new content or 604 * re-arranged its sections before calling elf_update(). Consequently 605 * its not safe to work `in place' on the original file. So we 606 * malloc() the required space for the updated ELF object and build 607 * the object there and write it out to the underlying file at the 608 * end. Note that the application may have opened the underlying file 609 * in ELF_C_RDWR and only retrieved/modified a few sections. We take 610 * care to avoid translating file sections unnecessarily. 611 * 612 * Gaps in the coverage of the file by the file's sections will be 613 * filled with the fill character set by elf_fill(3). 614 */ 615 616static off_t 617_libelf_write_elf(Elf *e, off_t newsize) 618{ 619 int ec; 620 off_t rc; 621 size_t fsz, msz, phnum, shnum; 622 uint64_t phoff, shoff; 623 void *ehdr; 624 char *newfile; 625 Elf_Data dst, src; 626 Elf_Scn *scn, *tscn; 627 Elf32_Ehdr *eh32; 628 Elf64_Ehdr *eh64; 629 630 assert(e->e_kind == ELF_K_ELF); 631 assert(e->e_cmd != ELF_C_READ); 632 assert(e->e_fd >= 0); 633 634 if ((newfile = malloc((size_t) newsize)) == NULL) { 635 LIBELF_SET_ERROR(RESOURCE, errno); 636 return ((off_t) -1); 637 } 638 639 ec = e->e_class; 640 641 ehdr = _libelf_ehdr(e, ec, 0); 642 assert(ehdr != NULL); 643 644 phnum = e->e_u.e_elf.e_nphdr; 645 646 if (ec == ELFCLASS32) { 647 eh32 = (Elf32_Ehdr *) ehdr; 648 649 phoff = (uint64_t) eh32->e_phoff; 650 shnum = eh32->e_shnum; 651 shoff = (uint64_t) eh32->e_shoff; 652 } else { 653 eh64 = (Elf64_Ehdr *) ehdr; 654 655 phoff = eh64->e_phoff; 656 shnum = eh64->e_shnum; 657 shoff = eh64->e_shoff; 658 } 659 660 fsz = _libelf_fsize(ELF_T_EHDR, ec, e->e_version, (size_t) 1); 661 msz = _libelf_msize(ELF_T_EHDR, ec, e->e_version); 662 663 (void) memset(&dst, 0, sizeof(dst)); 664 (void) memset(&src, 0, sizeof(src)); 665 666 src.d_buf = ehdr; 667 src.d_size = msz; 668 src.d_type = ELF_T_EHDR; 669 src.d_version = dst.d_version = e->e_version; 670 671 rc = 0; 672 673 dst.d_buf = newfile + rc; 674 dst.d_size = fsz; 675 676 if (_libelf_xlate(&dst, &src, e->e_byteorder, ec, ELF_TOFILE) == 677 NULL) 678 goto error; 679 680 rc += fsz; 681 682 /* 683 * Write the program header table if present. 684 */ 685 686 if (phnum != 0 && phoff != 0) { 687 assert((unsigned) rc <= phoff); 688 689 fsz = _libelf_fsize(ELF_T_PHDR, ec, e->e_version, phnum); 690 691 assert(phoff % _libelf_falign(ELF_T_PHDR, ec) == 0); 692 assert(fsz > 0); 693 694 src.d_version = dst.d_version = e->e_version; 695 src.d_type = ELF_T_PHDR; 696 697 if (ec == ELFCLASS32) 698 src.d_buf = e->e_u.e_elf.e_phdr.e_phdr32; 699 else 700 src.d_buf = e->e_u.e_elf.e_phdr.e_phdr64; 701 702 src.d_size = phnum * _libelf_msize(ELF_T_PHDR, ec, 703 e->e_version); 704 705 dst.d_size = fsz; 706 707 if ((uint64_t) rc < phoff) 708 (void) memset(newfile + rc, 709 LIBELF_PRIVATE(fillchar), phoff - rc); 710 711 dst.d_buf = newfile + rc; 712 713 if (_libelf_xlate(&dst, &src, e->e_byteorder, ec, ELF_TOFILE) == 714 NULL) 715 goto error; 716 717 rc = phoff + fsz; 718 } 719 720 /* 721 * Write out individual sections. 722 */ 723 724 STAILQ_FOREACH(scn, &e->e_u.e_elf.e_scn, s_next) 725 if ((rc = _libelf_write_scn(e, newfile, scn, rc)) < 0) 726 goto error; 727 728 /* 729 * Write out the section header table, if required. 730 */ 731 732 if (shnum != 0 && shoff != 0) { 733 assert((unsigned) rc <= shoff); 734 735 if ((uint64_t) rc < shoff) 736 (void) memset(newfile + rc, 737 LIBELF_PRIVATE(fillchar), shoff - rc); 738 739 rc = shoff; 740 741 assert(rc % _libelf_falign(ELF_T_SHDR, ec) == 0); 742 743 src.d_type = ELF_T_SHDR; 744 src.d_size = _libelf_msize(ELF_T_SHDR, ec, e->e_version); 745 src.d_version = dst.d_version = e->e_version; 746 747 fsz = _libelf_fsize(ELF_T_SHDR, ec, e->e_version, (size_t) 1); 748 749 STAILQ_FOREACH(scn, &e->e_u.e_elf.e_scn, s_next) { 750 if (ec == ELFCLASS32) 751 src.d_buf = &scn->s_shdr.s_shdr32; 752 else 753 src.d_buf = &scn->s_shdr.s_shdr64; 754 755 dst.d_size = fsz; 756 dst.d_buf = newfile + rc; 757 758 if (_libelf_xlate(&dst, &src, e->e_byteorder, ec, 759 ELF_TOFILE) != &dst) 760 goto error; 761 762 rc += fsz; 763 } 764 } 765 766 /* 767 */ 768 769 assert(rc == newsize); 770 771 /* 772 * Write out the constructed contents and remap the file in 773 * read-only. 774 */ 775 776 if (e->e_rawfile && munmap(e->e_rawfile, e->e_rawsize) < 0) { 777 LIBELF_SET_ERROR(IO, errno); 778 goto error; 779 } 780 781 if (write(e->e_fd, newfile, (size_t) newsize) != newsize || 782 lseek(e->e_fd, (off_t) 0, SEEK_SET) < 0) { 783 LIBELF_SET_ERROR(IO, errno); 784 goto error; 785 } 786 787 if (e->e_cmd != ELF_C_WRITE) { 788 if ((e->e_rawfile = mmap(NULL, (size_t) newsize, PROT_READ, 789 MAP_PRIVATE, e->e_fd, (off_t) 0)) == MAP_FAILED) { 790 LIBELF_SET_ERROR(IO, errno); 791 goto error; 792 } 793 e->e_rawsize = newsize; 794 } 795 796 /* 797 * Reset flags, remove existing section descriptors and 798 * {E,P}HDR pointers so that a subsequent elf_get{e,p}hdr() 799 * and elf_getscn() will function correctly. 800 */ 801 802 e->e_flags &= ~ELF_F_DIRTY; 803 804 STAILQ_FOREACH_SAFE(scn, &e->e_u.e_elf.e_scn, s_next, tscn) 805 _libelf_release_scn(scn); 806 807 if (ec == ELFCLASS32) { 808 free(e->e_u.e_elf.e_ehdr.e_ehdr32); 809 if (e->e_u.e_elf.e_phdr.e_phdr32) 810 free(e->e_u.e_elf.e_phdr.e_phdr32); 811 812 e->e_u.e_elf.e_ehdr.e_ehdr32 = NULL; 813 e->e_u.e_elf.e_phdr.e_phdr32 = NULL; 814 } else { 815 free(e->e_u.e_elf.e_ehdr.e_ehdr64); 816 if (e->e_u.e_elf.e_phdr.e_phdr64) 817 free(e->e_u.e_elf.e_phdr.e_phdr64); 818 819 e->e_u.e_elf.e_ehdr.e_ehdr64 = NULL; 820 e->e_u.e_elf.e_phdr.e_phdr64 = NULL; 821 } 822 823 return (rc); 824 825 error: 826 if (newfile) 827 free(newfile); 828 return ((off_t) -1); 829} 830 831off_t 832elf_update(Elf *e, Elf_Cmd c) 833{ 834 int ec; 835 off_t rc; 836 837 rc = (off_t) -1; 838 839 if (e == NULL || e->e_kind != ELF_K_ELF || 840 (c != ELF_C_NULL && c != ELF_C_WRITE)) { 841 LIBELF_SET_ERROR(ARGUMENT, 0); 842 return (rc); 843 } 844 845 if ((ec = e->e_class) != ELFCLASS32 && ec != ELFCLASS64) { 846 LIBELF_SET_ERROR(CLASS, 0); 847 return (rc); 848 } 849 850 if (e->e_version == EV_NONE) 851 e->e_version = EV_CURRENT; 852 853 if (c == ELF_C_WRITE && e->e_cmd == ELF_C_READ) { 854 LIBELF_SET_ERROR(MODE, 0); 855 return (rc); 856 } 857 858 if ((rc = _libelf_resync_elf(e)) < 0) 859 return (rc); 860 861 if (c == ELF_C_NULL) 862 return (rc); 863 864 if (e->e_cmd == ELF_C_READ) { 865 /* 866 * This descriptor was opened in read-only mode or by 867 * elf_memory(). 868 */ 869 if (e->e_fd) 870 LIBELF_SET_ERROR(MODE, 0); 871 else 872 LIBELF_SET_ERROR(ARGUMENT, 0); 873 return ((off_t) -1); 874 } 875 876 if (e->e_fd < 0) { 877 LIBELF_SET_ERROR(SEQUENCE, 0); 878 return ((off_t) -1); 879 } 880 881 return (_libelf_write_elf(e, rc)); 882} 883