Line data    Source code

       1             : /* Compute CRC32 checksum of file contents.
       2             :    Copyright (C) 2006 Red Hat, Inc.
       3             :    This file is part of elfutils.
       4             : 
       5             :    This file is free software; you can redistribute it and/or modify
       6             :    it under the terms of either
       7             : 
       8             :      * the GNU Lesser General Public License as published by the Free
       9             :        Software Foundation; either version 3 of the License, or (at
      10             :        your option) any later version
      11             : 
      12             :    or
      13             : 
      14             :      * the GNU General Public License as published by the Free
      15             :        Software Foundation; either version 2 of the License, or (at
      16             :        your option) any later version
      17             : 
      18             :    or both in parallel, as here.
      19             : 
      20             :    elfutils is distributed in the hope that it will be useful, but
      21             :    WITHOUT ANY WARRANTY; without even the implied warranty of
      22             :    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      23             :    General Public License for more details.
      24             : 
      25             :    You should have received copies of the GNU General Public License and
      26             :    the GNU Lesser General Public License along with this program.  If
      27             :    not, see <http://www.gnu.org/licenses/>.  */
      28             : 
      29             : #ifdef HAVE_CONFIG_H
      30             : # include <config.h>
      31             : #endif
      32             : 
      33             : #include "libeu.h"
      34             : #include <errno.h>
      35             : #include <unistd.h>
      36             : #include <sys/stat.h>
      37             : #include <sys/mman.h>
      38             : #include "system.h"
      39             : 
      40             : int
      41          61 : crc32_file (int fd, uint32_t *resp)
      42             : {
      43          61 :   unsigned char buffer[1024 * 8];
      44          61 :   uint32_t crc = 0;
      45          61 :   off_t off = 0;
      46          61 :   ssize_t count;
      47             : 
      48          61 :   struct stat st;
      49          61 :   if (fstat (fd, &st) == 0)
      50             :     {
      51             :       /* Try mapping in the file data.  */
      52          61 :       size_t mapsize = st.st_size;
      53          61 :       void *mapped = mmap (NULL, mapsize, PROT_READ, MAP_PRIVATE, fd, 0);
      54          61 :       if (mapped == MAP_FAILED && errno == ENOMEM)
      55             :         {
      56           0 :           const size_t pagesize = sysconf (_SC_PAGESIZE);
      57           0 :           mapsize = ((mapsize / 2) + pagesize - 1) & -pagesize;
      58           0 :           while (mapsize >= pagesize
      59           0 :                  && (mapped = mmap (NULL, mapsize, PROT_READ, MAP_PRIVATE,
      60           0 :                                     fd, 0)) == MAP_FAILED && errno == ENOMEM)
      61           0 :             mapsize /= 2;
      62             :         }
      63          61 :       if (mapped != MAP_FAILED)
      64             :         {
      65          61 :           do
      66             :             {
      67          61 :               if (st.st_size <= (off_t) mapsize)
      68             :                 {
      69          61 :                   *resp = crc32 (crc, mapped, st.st_size);
      70          61 :                   munmap (mapped, mapsize);
      71          61 :                   return 0;
      72             :                 }
      73           0 :               crc = crc32 (crc, mapped, mapsize);
      74           0 :               off += mapsize;
      75           0 :               st.st_size -= mapsize;
      76           0 :             } while (mmap (mapped, mapsize, PROT_READ, MAP_FIXED|MAP_PRIVATE,
      77           0 :                            fd, off) == mapped);
      78           0 :           munmap (mapped, mapsize);
      79             :         }
      80             :     }
      81             : 
      82           0 :   while ((count = TEMP_FAILURE_RETRY (pread (fd, buffer, sizeof buffer,
      83             :                                              off))) > 0)
      84             :     {
      85           0 :       off += count;
      86           0 :       crc = crc32 (crc, buffer, count);
      87             :     }
      88             : 
      89           0 :   *resp = crc;
      90             : 
      91           0 :   return count == 0 ? 0 : -1;
      92             : }