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#ifdef __sun 31#include <sys/sysmacros.h> 32#endif 33 34#include <assert.h> 35#include <errno.h> 36#include "gelf.h" 37#include "libelf.h" 38#include <stdlib.h> 39#include <string.h> 40#include <unistd.h> 41 42#include "_libelf.h" 43 44/* 45 * Update the internal data structures associated with an ELF object. 46 * Returns the size in bytes the ELF object would occupy in its file 47 * representation. 48 * 49 * After a successful call to this function, the following structures 50 * are updated: 51 * 52 * - The ELF header is updated. 53 * - All sections are sorted in order of ascending addresses and their 54 * section header table entries updated. An error is signalled 55 * if an overlap was detected among sections. 56 * - All data descriptors associated with a section are sorted in order 57 * of ascending addresses. Overlaps, if detected, are signalled as 58 * errors. Other sanity checks for alignments, section types etc. are 59 * made. 60 * 61 * After a resync_elf() successfully returns, the ELF descriptor is 62 * ready for being handed over to _libelf_write_elf(). 63 * 64 * File alignments: 65 * PHDR - Addr 66 * SHDR - Addr 67 * 68 * XXX: how do we handle 'flags'. 69 */ 70 71/* 72 * Compute the extents of a section, by looking at the. 73 */ 74static int 75_libelf_compute_section_extents(Elf *e, Elf_Scn *s, off_t *rc) 76{ 77 int ec; 78 Elf_Data *d, *td; 79 unsigned int elftype; 80 uint32_t sh_type; 81 uint64_t d_align; 82 uint64_t sh_align, sh_entsize, sh_offset, sh_size; 83 uint64_t scn_size, scn_alignment; 84 85 /* 86 * We need to recompute library private data structures if one 87 * or more of the following is true: 88 * - The underlying Shdr structure has been marked `dirty'. Significant 89 * fields include: `sh_offset', `sh_type', `sh_size', `sh_addralign'. 90 * - The Elf_Data structures part of this section have been marked 91 * `dirty'. Affected members include `d_align', `d_offset', `d_type', 92 * and `d_size'. 93 * - The section as a whole is `dirty', e.g., it has been allocated 94 * using elf_newscn(), or if a new Elf_Data structure was added using 95 * elf_newdata(). 96 * 97 * Each of these conditions would result in the ELF_F_DIRTY bit being 98 * set on the section descriptor's `s_flags' field. 99 */ 100 101 ec = e->e_class; 102 103 if (ec == ELFCLASS32) { 104 sh_type = s->s_shdr.s_shdr32.sh_type; 105 sh_align = (uint64_t) s->s_shdr.s_shdr32.sh_addralign; 106 sh_entsize = (uint64_t) s->s_shdr.s_shdr32.sh_entsize; 107 sh_offset = (uint64_t) s->s_shdr.s_shdr32.sh_offset; 108 sh_size = (uint64_t) s->s_shdr.s_shdr32.sh_size; 109 } else { 110 sh_type = s->s_shdr.s_shdr64.sh_type; 111 sh_align = s->s_shdr.s_shdr64.sh_addralign; 112 sh_entsize = s->s_shdr.s_shdr64.sh_entsize; 113 sh_offset = s->s_shdr.s_shdr64.sh_offset; 114 sh_size = s->s_shdr.s_shdr64.sh_size; 115 } 116 117 if (sh_type == SHT_NULL || sh_type == SHT_NOBITS) 118 return (1); 119 120 if ((s->s_flags & ELF_F_DIRTY) == 0) { 121 if ((size_t) *rc < sh_offset + sh_size) 122 *rc = sh_offset + sh_size; 123 return (1); 124 } 125 126 elftype = _libelf_xlate_shtype(sh_type); 127 if (elftype > ELF_T_LAST) { 128 LIBELF_SET_ERROR(SECTION, 0); 129 return (0); 130 } 131 132 /* 133 * Compute the extent of the data descriptors associated with 134 * this section. 135 */ 136 scn_alignment = 0; 137 if (sh_align == 0) 138 sh_align = _libelf_falign(elftype, ec); 139 140 /* Compute the section alignment. */ 141 STAILQ_FOREACH(d, &s->s_data, d_next) { 142 if (d->d_type != elftype) { 143 LIBELF_SET_ERROR(DATA, 0); 144 return (0); 145 } 146 if (d->d_version != e->e_version) { 147 LIBELF_SET_ERROR(VERSION, 0); 148 return (0); 149 } 150 if ((d_align = d->d_align) % sh_align) { 151 LIBELF_SET_ERROR(LAYOUT, 0); 152 return (0); 153 } 154 if (d_align == 0 || (d_align & (d_align - 1))) { 155 LIBELF_SET_ERROR(DATA, 0); 156 return (0); 157 } 158 if (d_align > scn_alignment) 159 scn_alignment = d_align; 160 } 161 162 scn_size = 0L; 163 164 STAILQ_FOREACH_SAFE(d, &s->s_data, d_next, td) { 165 if (e->e_flags & ELF_F_LAYOUT) { 166 if ((uint64_t) d->d_off + d->d_size > scn_size) 167 scn_size = d->d_off + d->d_size; 168 } else { 169 scn_size = roundup(scn_size, scn_alignment); 170 d->d_off = scn_size; 171 scn_size += d->d_size; 172 } 173 } 174 175 /* 176 * If the application is requesting full control over the layout 177 * of the section, check its values for sanity. 178 */ 179 if (e->e_flags & ELF_F_LAYOUT) { 180 if (scn_alignment > sh_align || sh_offset % sh_align || 181 sh_size < scn_size) { 182 LIBELF_SET_ERROR(LAYOUT, 0); 183 return (0); 184 } 185 } else { 186 /* 187 * Otherwise compute the values in the section header. 188 */ 189 190 if (scn_alignment > sh_align) 191 sh_align = scn_alignment; 192 193 /* 194 * If the section entry size is zero, try and fill in an 195 * appropriate entry size. Per the elf(5) manual page 196 * sections without fixed-size entries should have their 197 * 'sh_entsize' field set to zero. 198 */ 199 if (sh_entsize == 0 && 200 (sh_entsize = _libelf_fsize(elftype, ec, e->e_version, 201 (size_t) 1)) == 1) 202 sh_entsize = 0; 203 204 sh_size = scn_size; 205 sh_offset = roundup(*rc, sh_align); 206 207 if (ec == ELFCLASS32) { 208 s->s_shdr.s_shdr32.sh_addralign = (uint32_t) sh_align; 209 s->s_shdr.s_shdr32.sh_entsize = (uint32_t) sh_entsize; 210 s->s_shdr.s_shdr32.sh_offset = (uint32_t) sh_offset; 211 s->s_shdr.s_shdr32.sh_size = (uint32_t) sh_size; 212 } else { 213 s->s_shdr.s_shdr64.sh_addralign = sh_align; 214 s->s_shdr.s_shdr64.sh_entsize = sh_entsize; 215 s->s_shdr.s_shdr64.sh_offset = sh_offset; 216 s->s_shdr.s_shdr64.sh_size = sh_size; 217 } 218 } 219 220 if ((size_t) *rc < sh_offset + sh_size) 221 *rc = sh_offset + sh_size; 222 223 s->s_size = sh_size; 224 s->s_offset = sh_offset; 225 return (1); 226} 227 228 229/* 230 * Insert a section in ascending order in the list 231 */ 232 233static int 234_libelf_insert_section(Elf *e, Elf_Scn *s) 235{ 236 Elf_Scn *t, *prevt; 237 uint64_t smax, smin, tmax, tmin; 238 239 smin = s->s_offset; 240 smax = smin + s->s_size; 241 242 prevt = NULL; 243 STAILQ_FOREACH(t, &e->e_u.e_elf.e_scn, s_next) { 244 tmin = t->s_offset; 245 tmax = tmin + t->s_size; 246 247 /* check if there is an overlap */ 248 if (tmax < smin) { 249 prevt = t; 250 continue; 251 } else if (smax < tmin) 252 break; 253 else { 254 LIBELF_SET_ERROR(LAYOUT, 0); 255 return (0); 256 } 257 } 258 259 if (prevt) 260 STAILQ_INSERT_AFTER(&e->e_u.e_elf.e_scn, prevt, s, s_next); 261 else 262 STAILQ_INSERT_HEAD(&e->e_u.e_elf.e_scn, s, s_next); 263 return (1); 264} 265 266static off_t 267_libelf_resync_sections(Elf *e, off_t rc) 268{ 269 int ec; 270 off_t nrc; 271 size_t sh_type; 272 Elf_Scn *s, *ts; 273 274 ec = e->e_class; 275 276 /* 277 * Make a pass through sections, computing the extent of each 278 * section. Order in increasing order of addresses. 279 */ 280 281 nrc = rc; 282 STAILQ_FOREACH(s, &e->e_u.e_elf.e_scn, s_next) 283 if (_libelf_compute_section_extents(e, s, &nrc) == 0) 284 return ((off_t) -1); 285 286 STAILQ_FOREACH_SAFE(s, &e->e_u.e_elf.e_scn, s_next, ts) { 287 if (ec == ELFCLASS32) 288 sh_type = s->s_shdr.s_shdr32.sh_type; 289 else 290 sh_type = s->s_shdr.s_shdr64.sh_type; 291 292 /* XXX Do we need the 'size' field of an SHT_NOBITS section */ 293 if (sh_type == SHT_NOBITS || sh_type == SHT_NULL) 294 continue; 295 296 if (s->s_offset < (uint64_t) rc) { 297 if (s->s_offset + s->s_size < (uint64_t) rc) { 298 /* 299 * Try insert this section in the 300 * correct place in the list, 301 * detecting overlaps if any. 302 */ 303 STAILQ_REMOVE(&e->e_u.e_elf.e_scn, s, _Elf_Scn, 304 s_next); 305 if (_libelf_insert_section(e, s) == 0) 306 return ((off_t) -1); 307 } else { 308 LIBELF_SET_ERROR(LAYOUT, 0); 309 return ((off_t) -1); 310 } 311 } else 312 rc = s->s_offset + s->s_size; 313 } 314 315 assert(nrc == rc); 316 317 return (rc); 318} 319 320static off_t 321_libelf_resync_elf(Elf *e) 322{ 323 int ec, eh_class, eh_type; 324 unsigned int eh_byteorder, eh_version; 325 size_t align, fsz; 326 size_t phnum, shnum; 327 off_t rc, phoff, shoff; 328 void *ehdr; 329 Elf32_Ehdr *eh32; 330 Elf64_Ehdr *eh64; 331 332 rc = 0; 333 334 ec = e->e_class; 335 336 assert(ec == ELFCLASS32 || ec == ELFCLASS64); 337 338 /* 339 * Prepare the EHDR. 340 */ 341 if ((ehdr = _libelf_ehdr(e, ec, 0)) == NULL) 342 return ((off_t) -1); 343 344 eh32 = ehdr; 345 eh64 = ehdr; 346 347 if (ec == ELFCLASS32) { 348 eh_byteorder = eh32->e_ident[EI_DATA]; 349 eh_class = eh32->e_ident[EI_CLASS]; 350 phoff = (uint64_t) eh32->e_phoff; 351 shoff = (uint64_t) eh32->e_shoff; 352 eh_type = eh32->e_type; 353 eh_version = eh32->e_version; 354 } else { 355 eh_byteorder = eh64->e_ident[EI_DATA]; 356 eh_class = eh64->e_ident[EI_CLASS]; 357 phoff = eh64->e_phoff; 358 shoff = eh64->e_shoff; 359 eh_type = eh64->e_type; 360 eh_version = eh64->e_version; 361 } 362 363 if (eh_version == EV_NONE) 364 eh_version = EV_CURRENT; 365 366 if (eh_version != e->e_version) { /* always EV_CURRENT */ 367 LIBELF_SET_ERROR(VERSION, 0); 368 return ((off_t) -1); 369 } 370 371 if (eh_class != e->e_class) { 372 LIBELF_SET_ERROR(CLASS, 0); 373 return ((off_t) -1); 374 } 375 376 if (e->e_cmd != ELF_C_WRITE && eh_byteorder != e->e_byteorder) { 377 LIBELF_SET_ERROR(HEADER, 0); 378 return ((off_t) -1); 379 } 380 381 shnum = e->e_u.e_elf.e_nscn; 382 phnum = e->e_u.e_elf.e_nphdr; 383 384 e->e_byteorder = eh_byteorder; 385 386#define INITIALIZE_EHDR(E,EC,V) do { \ 387 (E)->e_ident[EI_MAG0] = ELFMAG0; \ 388 (E)->e_ident[EI_MAG1] = ELFMAG1; \ 389 (E)->e_ident[EI_MAG2] = ELFMAG2; \ 390 (E)->e_ident[EI_MAG3] = ELFMAG3; \ 391 (E)->e_ident[EI_CLASS] = (EC); \ 392 (E)->e_ident[EI_VERSION] = (V); \ 393 (E)->e_ehsize = _libelf_fsize(ELF_T_EHDR, (EC), (V), \ 394 (size_t) 1); \ 395 (E)->e_phentsize = _libelf_fsize(ELF_T_PHDR, (EC), (V), \ 396 (size_t) 1); \ 397 (E)->e_shentsize = _libelf_fsize(ELF_T_SHDR, (EC), (V), \ 398 (size_t) 1); \ 399 } while (0) 400 401 if (ec == ELFCLASS32) 402 INITIALIZE_EHDR(eh32, ec, eh_version); 403 else 404 INITIALIZE_EHDR(eh64, ec, eh_version); 405 406 (void) elf_flagehdr(e, ELF_C_SET, ELF_F_DIRTY); 407 408 rc += _libelf_fsize(ELF_T_EHDR, ec, eh_version, (size_t) 1); 409 410 /* 411 * Compute the layout the program header table, if one is 412 * present. The program header table needs to be aligned to a 413 * `natural' boundary. 414 */ 415 if (phnum) { 416 fsz = _libelf_fsize(ELF_T_PHDR, ec, eh_version, phnum); 417 align = _libelf_falign(ELF_T_PHDR, ec); 418 419 if (e->e_flags & ELF_F_LAYOUT) { 420 /* 421 * Check offsets for sanity. 422 */ 423 if (rc > phoff) { 424 LIBELF_SET_ERROR(HEADER, 0); 425 return ((off_t) -1); 426 } 427 428 if (phoff % align) { 429 LIBELF_SET_ERROR(LAYOUT, 0); 430 return ((off_t) -1); 431 } 432 433 } else 434 phoff = roundup(rc, align); 435 436 rc = phoff + fsz; 437 } else 438 phoff = 0; 439 440 /* 441 * Compute the layout of the sections associated with the 442 * file. 443 */ 444 445 if ((rc = _libelf_resync_sections(e, rc)) < 0) 446 return ((off_t) -1); 447 448 /* 449 * Compute the space taken up by the section header table, if 450 * one is needed. 451 */ 452 if (shnum) { 453 fsz = _libelf_fsize(ELF_T_SHDR, ec, eh_version, (size_t) 1); 454 align = _libelf_falign(ELF_T_SHDR, ec); 455 456 if (e->e_flags & ELF_F_LAYOUT) { 457 if (rc > shoff) { 458 LIBELF_SET_ERROR(HEADER, 0); 459 return ((off_t) -1); 460 } 461 462 if (shoff % align) { 463 LIBELF_SET_ERROR(LAYOUT, 0); 464 return ((off_t) -1); 465 } 466 } else 467 shoff = roundup(rc, align); 468 469 rc = shoff + fsz * shnum; 470 } else 471 shoff = 0; 472 473 /* 474 * Set the fields of the Executable Header that could potentially use 475 * extended numbering. 476 */ 477 _libelf_setphnum(e, ehdr, ec, phnum); 478 _libelf_setshnum(e, ehdr, ec, shnum); 479 480 /* 481 * Update the `e_phoff' and `e_shoff' fields if the library is 482 * doing the layout. 483 */ 484 if ((e->e_flags & ELF_F_LAYOUT) == 0) { 485 if (ec == ELFCLASS32) { 486 eh32->e_phoff = (uint32_t) phoff; 487 eh32->e_shoff = (uint32_t) shoff; 488 } else { 489 eh64->e_phoff = (uint64_t) phoff; 490 eh64->e_shoff = (uint64_t) shoff; 491 } 492 } 493 494 return (rc); 495} 496 497/* 498 * Write out the contents of a section. 499 */ 500 501static off_t 502_libelf_write_scn(Elf *e, char *nf, Elf_Scn *s, off_t rc) 503{ 504 int ec; 505 size_t fsz, msz, nobjects; 506 uint32_t sh_type; 507 uint64_t sh_off; 508 int elftype; 509 Elf_Data *d, dst; 510 511 if ((ec = e->e_class) == ELFCLASS32) 512 sh_type = s->s_shdr.s_shdr32.sh_type; 513 else 514 sh_type = s->s_shdr.s_shdr64.sh_type; 515 516 /* 517 * Ignore sections that do not allocate space in the file. 518 */ 519 if (sh_type == SHT_NOBITS || sh_type == SHT_NULL) 520 return (rc); 521 522 523 elftype = _libelf_xlate_shtype(sh_type); 524 assert(elftype >= ELF_T_FIRST && elftype <= ELF_T_LAST); 525 526 msz = _libelf_msize(elftype, ec, e->e_version); 527 528 sh_off = s->s_offset; 529 assert(sh_off % _libelf_falign(elftype, ec) == 0); 530 531 /* 532 * If the section has a `rawdata' descriptor, and the section 533 * contents have not been modified, use its contents directly. 534 * The `s_rawoff' member contains the offset into the original 535 * file, while `s_offset' contains its new location in the 536 * destination. 537 */ 538 539 if (STAILQ_EMPTY(&s->s_data)) { 540 541 if ((d = elf_rawdata(s, NULL)) == NULL) 542 return ((off_t) -1); 543 544 STAILQ_FOREACH(d, &s->s_rawdata, d_next) { 545 if ((uint64_t) rc < sh_off + d->d_off) 546 (void) memset(nf + rc, 547 LIBELF_PRIVATE(fillchar), sh_off + 548 d->d_off - rc); 549 rc = sh_off + d->d_off; 550 551 assert(d->d_buf != NULL); 552 assert(d->d_type == ELF_T_BYTE); 553 assert(d->d_version == e->e_version); 554 555 (void) memcpy(nf + rc, 556 e->e_rawfile + s->s_rawoff + d->d_off, d->d_size); 557 558 rc += d->d_size; 559 } 560 561 return (rc); 562 } 563 564 /* 565 * Iterate over the set of data descriptors for this section. 566 * The prior call to _libelf_resync_elf() would have setup the 567 * descriptors for this step. 568 */ 569 570 dst.d_version = e->e_version; 571 572 STAILQ_FOREACH(d, &s->s_data, d_next) { 573 574 if ((uint64_t) rc < sh_off + d->d_off) 575 (void) memset(nf + rc, 576 LIBELF_PRIVATE(fillchar), sh_off + d->d_off - rc); 577 578 rc = sh_off + d->d_off; 579 580 assert(d->d_buf != NULL); 581 assert(d->d_type == (Elf_Type) elftype); 582 assert(d->d_version == e->e_version); 583 assert(d->d_size % msz == 0); 584 585 nobjects = d->d_size / msz; 586 587 fsz = _libelf_fsize(elftype, ec, e->e_version, nobjects); 588 589 dst.d_buf = nf + rc; 590 dst.d_size = fsz; 591 592 if (_libelf_xlate(&dst, d, e->e_byteorder, ec, ELF_TOFILE) == 593 NULL) 594 return ((off_t) -1); 595 596 rc += fsz; 597 } 598 599 return ((off_t) rc); 600} 601 602/* 603 * Write out the file image. 604 * 605 * The original file could have been mapped in with an ELF_C_RDWR 606 * command and the application could have added new content or 607 * re-arranged its sections before calling elf_update(). Consequently 608 * its not safe to work `in place' on the original file. So we 609 * malloc() the required space for the updated ELF object and build 610 * the object there and write it out to the underlying file at the 611 * end. Note that the application may have opened the underlying file 612 * in ELF_C_RDWR and only retrieved/modified a few sections. We take 613 * care to avoid translating file sections unnecessarily. 614 * 615 * Gaps in the coverage of the file by the file's sections will be 616 * filled with the fill character set by elf_fill(3). 617 */ 618 619static off_t 620_libelf_write_elf(Elf *e, off_t newsize) 621{ 622 int ec; 623 off_t rc; 624 size_t fsz, msz, phnum, shnum; 625 uint64_t phoff, shoff; 626 void *ehdr; 627 char *newfile; 628 Elf_Data dst, src; 629 Elf_Scn *scn, *tscn; 630 Elf32_Ehdr *eh32; 631 Elf64_Ehdr *eh64; 632 633 assert(e->e_kind == ELF_K_ELF); 634 assert(e->e_cmd != ELF_C_READ); 635 assert(e->e_fd >= 0); 636 637 if ((newfile = malloc((size_t) newsize)) == NULL) { 638 LIBELF_SET_ERROR(RESOURCE, errno); 639 return ((off_t) -1); 640 } 641 642 ec = e->e_class; 643 644 ehdr = _libelf_ehdr(e, ec, 0); 645 assert(ehdr != NULL); 646 647 phnum = e->e_u.e_elf.e_nphdr; 648 649 if (ec == ELFCLASS32) { 650 eh32 = (Elf32_Ehdr *) ehdr; 651 652 phoff = (uint64_t) eh32->e_phoff; 653 shnum = eh32->e_shnum; 654 shoff = (uint64_t) eh32->e_shoff; 655 } else { 656 eh64 = (Elf64_Ehdr *) ehdr; 657 658 phoff = eh64->e_phoff; 659 shnum = eh64->e_shnum; 660 shoff = eh64->e_shoff; 661 } 662 663 fsz = _libelf_fsize(ELF_T_EHDR, ec, e->e_version, (size_t) 1); 664 msz = _libelf_msize(ELF_T_EHDR, ec, e->e_version); 665 666 (void) memset(&dst, 0, sizeof(dst)); 667 (void) memset(&src, 0, sizeof(src)); 668 669 src.d_buf = ehdr; 670 src.d_size = msz; 671 src.d_type = ELF_T_EHDR; 672 src.d_version = dst.d_version = e->e_version; 673 674 rc = 0; 675 676 dst.d_buf = newfile + rc; 677 dst.d_size = fsz; 678 679 if (_libelf_xlate(&dst, &src, e->e_byteorder, ec, ELF_TOFILE) == 680 NULL) 681 goto error; 682 683 rc += fsz; 684 685 /* 686 * Write the program header table if present. 687 */ 688 689 if (phnum != 0 && phoff != 0) { 690 assert((unsigned) rc <= phoff); 691 692 fsz = _libelf_fsize(ELF_T_PHDR, ec, e->e_version, phnum); 693 694 assert(phoff % _libelf_falign(ELF_T_PHDR, ec) == 0); 695 assert(fsz > 0); 696 697 src.d_version = dst.d_version = e->e_version; 698 src.d_type = ELF_T_PHDR; 699 700 if (ec == ELFCLASS32) 701 src.d_buf = e->e_u.e_elf.e_phdr.e_phdr32; 702 else 703 src.d_buf = e->e_u.e_elf.e_phdr.e_phdr64; 704 705 src.d_size = phnum * _libelf_msize(ELF_T_PHDR, ec, 706 e->e_version); 707 708 dst.d_size = fsz; 709 710 if ((uint64_t) rc < phoff) 711 (void) memset(newfile + rc, 712 LIBELF_PRIVATE(fillchar), phoff - rc); 713 714 dst.d_buf = newfile + rc; 715 716 if (_libelf_xlate(&dst, &src, e->e_byteorder, ec, ELF_TOFILE) == 717 NULL) 718 goto error; 719 720 rc = phoff + fsz; 721 } 722 723 /* 724 * Write out individual sections. 725 */ 726 727 STAILQ_FOREACH(scn, &e->e_u.e_elf.e_scn, s_next) 728 if ((rc = _libelf_write_scn(e, newfile, scn, rc)) < 0) 729 goto error; 730 731 /* 732 * Write out the section header table, if required. 733 */ 734 735 if (shnum != 0 && shoff != 0) { 736 assert((unsigned) rc <= shoff); 737 738 if ((uint64_t) rc < shoff) 739 (void) memset(newfile + rc, 740 LIBELF_PRIVATE(fillchar), shoff - rc); 741 742 rc = shoff; 743 744 assert(rc % _libelf_falign(ELF_T_SHDR, ec) == 0); 745 746 src.d_type = ELF_T_SHDR; 747 src.d_size = _libelf_msize(ELF_T_SHDR, ec, e->e_version); 748 src.d_version = dst.d_version = e->e_version; 749 750 fsz = _libelf_fsize(ELF_T_SHDR, ec, e->e_version, (size_t) 1); 751 752 STAILQ_FOREACH(scn, &e->e_u.e_elf.e_scn, s_next) { 753 if (ec == ELFCLASS32) 754 src.d_buf = &scn->s_shdr.s_shdr32; 755 else 756 src.d_buf = &scn->s_shdr.s_shdr64; 757 758 dst.d_size = fsz; 759 dst.d_buf = newfile + rc; 760 761 if (_libelf_xlate(&dst, &src, e->e_byteorder, ec, 762 ELF_TOFILE) != &dst) 763 goto error; 764 765 rc += fsz; 766 } 767 } 768 769 /* 770 */ 771 772 assert(rc == newsize); 773 774 /* 775 * Write out the constructed contents and remap the file in 776 * read-only. 777 */ 778 779 if (e->e_rawfile && munmap(e->e_rawfile, e->e_rawsize) < 0) { 780 LIBELF_SET_ERROR(IO, errno); 781 goto error; 782 } 783 784 if (write(e->e_fd, newfile, (size_t) newsize) != newsize || 785 lseek(e->e_fd, (off_t) 0, SEEK_SET) < 0) { 786 LIBELF_SET_ERROR(IO, errno); 787 goto error; 788 } 789 790 if (e->e_cmd != ELF_C_WRITE) { 791 if ((e->e_rawfile = mmap(NULL, (size_t) newsize, PROT_READ, 792 MAP_PRIVATE, e->e_fd, (off_t) 0)) == MAP_FAILED) { 793 LIBELF_SET_ERROR(IO, errno); 794 goto error; 795 } 796 e->e_rawsize = newsize; 797 } 798 799 /* 800 * Reset flags, remove existing section descriptors and 801 * {E,P}HDR pointers so that a subsequent elf_get{e,p}hdr() 802 * and elf_getscn() will function correctly. 803 */ 804 805 e->e_flags &= ~ELF_F_DIRTY; 806 807 STAILQ_FOREACH_SAFE(scn, &e->e_u.e_elf.e_scn, s_next, tscn) 808 _libelf_release_scn(scn); 809 810 if (ec == ELFCLASS32) { 811 free(e->e_u.e_elf.e_ehdr.e_ehdr32); 812 if (e->e_u.e_elf.e_phdr.e_phdr32) 813 free(e->e_u.e_elf.e_phdr.e_phdr32); 814 815 e->e_u.e_elf.e_ehdr.e_ehdr32 = NULL; 816 e->e_u.e_elf.e_phdr.e_phdr32 = NULL; 817 } else { 818 free(e->e_u.e_elf.e_ehdr.e_ehdr64); 819 if (e->e_u.e_elf.e_phdr.e_phdr64) 820 free(e->e_u.e_elf.e_phdr.e_phdr64); 821 822 e->e_u.e_elf.e_ehdr.e_ehdr64 = NULL; 823 e->e_u.e_elf.e_phdr.e_phdr64 = NULL; 824 } 825 826 return (rc); 827 828 error: 829 if (newfile) 830 free(newfile); 831 return ((off_t) -1); 832} 833 834off_t 835elf_update(Elf *e, Elf_Cmd c) 836{ 837 int ec; 838 off_t rc; 839 840 rc = (off_t) -1; 841 842 if (e == NULL || e->e_kind != ELF_K_ELF || 843 (c != ELF_C_NULL && c != ELF_C_WRITE)) { 844 LIBELF_SET_ERROR(ARGUMENT, 0); 845 return (rc); 846 } 847 848 if ((ec = e->e_class) != ELFCLASS32 && ec != ELFCLASS64) { 849 LIBELF_SET_ERROR(CLASS, 0); 850 return (rc); 851 } 852 853 if (e->e_version == EV_NONE) 854 e->e_version = EV_CURRENT; 855 856 if (c == ELF_C_WRITE && e->e_cmd == ELF_C_READ) { 857 LIBELF_SET_ERROR(MODE, 0); 858 return (rc); 859 } 860 861 if ((rc = _libelf_resync_elf(e)) < 0) 862 return (rc); 863 864 if (c == ELF_C_NULL) 865 return (rc); 866 867 if (e->e_cmd == ELF_C_READ) { 868 /* 869 * This descriptor was opened in read-only mode or by 870 * elf_memory(). 871 */ 872 if (e->e_fd) 873 LIBELF_SET_ERROR(MODE, 0); 874 else 875 LIBELF_SET_ERROR(ARGUMENT, 0); 876 return ((off_t) -1); 877 } 878 879 if (e->e_fd < 0) { 880 LIBELF_SET_ERROR(SEQUENCE, 0); 881 return ((off_t) -1); 882 } 883 884 return (_libelf_write_elf(e, rc)); 885} 886