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, 16 Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301 USA. 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 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 } 108
