Ulrich Drepper | 361df7d | 2006-04-04 21:38:57 +0000 | [diff] [blame] | 1 | /* Compute CRC32 checksum of file contents. |
| 2 | Copyright (C) 2006 Red Hat, Inc. |
| 3 | This file is part of Red Hat elfutils. |
| 4 | |
| 5 | Red Hat elfutils is free software; you can redistribute it and/or modify |
| 6 | it under the terms of the GNU General Public License as published by the |
| 7 | Free Software Foundation; version 2 of the License. |
| 8 | |
| 9 | Red Hat elfutils is distributed in the hope that it will be useful, but |
| 10 | WITHOUT ANY WARRANTY; without even the implied warranty of |
| 11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 12 | General Public License for more details. |
| 13 | |
| 14 | You should have received a copy of the GNU General Public License along |
| 15 | with Red Hat elfutils; if not, write to the Free Software Foundation, |
Ulrich Drepper | 1e9ef50 | 2006-04-04 22:29:06 +0000 | [diff] [blame] | 16 | Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301 USA. |
Ulrich Drepper | 361df7d | 2006-04-04 21:38:57 +0000 | [diff] [blame] | 17 | |
| 18 | In addition, as a special exception, Red Hat, Inc. gives You the |
| 19 | additional right to link the code of Red Hat elfutils with code licensed |
| 20 | under an Open Source Initiative certified open source license |
| 21 | (http://www.opensource.org/licenses/index.php) and to distribute linked |
| 22 | combinations including the two. Non-GPL Code permitted under this |
| 23 | exception must only link to the code of Red Hat elfutils through those |
| 24 | well defined interfaces identified in the file named EXCEPTION found in |
| 25 | the source code files (the "Approved Interfaces"). The files of Non-GPL |
| 26 | Code may instantiate templates or use macros or inline functions from |
| 27 | the Approved Interfaces without causing the resulting work to be covered |
| 28 | by the GNU General Public License. Only Red Hat, Inc. may make changes |
| 29 | or additions to the list of Approved Interfaces. Red Hat's grant of |
| 30 | this exception is conditioned upon your not adding any new exceptions. |
| 31 | If you wish to add a new Approved Interface or exception, please contact |
| 32 | Red Hat. You must obey the GNU General Public License in all respects |
| 33 | for all of the Red Hat elfutils code and other code used in conjunction |
| 34 | with Red Hat elfutils except the Non-GPL Code covered by this exception. |
| 35 | If you modify this file, you may extend this exception to your version |
| 36 | of the file, but you are not obligated to do so. If you do not wish to |
| 37 | provide this exception without modification, you must delete this |
| 38 | exception statement from your version and license this file solely under |
| 39 | the GPL without exception. |
| 40 | |
| 41 | Red Hat elfutils is an included package of the Open Invention Network. |
| 42 | An included package of the Open Invention Network is a package for which |
| 43 | Open Invention Network licensees cross-license their patents. No patent |
| 44 | license is granted, either expressly or impliedly, by designation as an |
| 45 | included package. Should you wish to participate in the Open Invention |
| 46 | Network licensing program, please visit www.openinventionnetwork.com |
| 47 | <http://www.openinventionnetwork.com>. */ |
| 48 | |
Ulrich Drepper | b08d5a8 | 2005-07-26 05:00:05 +0000 | [diff] [blame] | 49 | #include "system.h" |
| 50 | #include <errno.h> |
| 51 | #include <unistd.h> |
| 52 | #include <sys/stat.h> |
| 53 | #include <sys/mman.h> |
| 54 | |
| 55 | int |
| 56 | crc32_file (int fd, uint32_t *resp) |
| 57 | { |
| 58 | unsigned char buffer[1024 * 8]; |
| 59 | uint32_t crc = 0; |
| 60 | off_t off = 0; |
| 61 | ssize_t count; |
| 62 | |
| 63 | struct stat st; |
| 64 | if (fstat (fd, &st) == 0) |
| 65 | { |
| 66 | /* Try mapping in the file data. */ |
| 67 | size_t mapsize = st.st_size; |
| 68 | void *mapped = mmap (NULL, mapsize, PROT_READ, MAP_PRIVATE, fd, 0); |
| 69 | if (mapped == MAP_FAILED && errno == ENOMEM) |
| 70 | { |
| 71 | const size_t pagesize = sysconf (_SC_PAGE_SIZE); |
| 72 | mapsize = ((mapsize / 2) + pagesize - 1) & -pagesize; |
| 73 | while (mapsize >= pagesize |
| 74 | && (mapped = mmap (NULL, mapsize, PROT_READ, MAP_PRIVATE, |
| 75 | fd, 0)) == MAP_FAILED && errno == ENOMEM) |
| 76 | mapsize /= 2; |
| 77 | } |
| 78 | if (mapped != MAP_FAILED) |
| 79 | { |
| 80 | do |
| 81 | { |
| 82 | if (st.st_size <= (off_t) mapsize) |
| 83 | { |
| 84 | *resp = crc32 (crc, mapped, st.st_size); |
| 85 | munmap (mapped, mapsize); |
| 86 | return 0; |
| 87 | } |
| 88 | crc = crc32 (crc, mapped, mapsize); |
| 89 | off += mapsize; |
| 90 | st.st_size -= mapsize; |
| 91 | } while (mmap (mapped, mapsize, PROT_READ, MAP_FIXED|MAP_PRIVATE, |
| 92 | fd, off) == mapped); |
| 93 | munmap (mapped, mapsize); |
| 94 | } |
| 95 | } |
| 96 | |
| 97 | while ((count = TEMP_FAILURE_RETRY (pread (fd, buffer, sizeof buffer, |
| 98 | off))) > 0) |
| 99 | { |
| 100 | off += count; |
| 101 | crc = crc32 (crc, buffer, count); |
| 102 | } |
| 103 | |
| 104 | *resp = crc; |
| 105 | |
| 106 | return count == 0 ? 0 : -1; |
| 107 | } |