gnu/dist/gettext/gettext-tools/lib/copy-file.c

   1 /* Copying of files.
   2    Copyright (C) 2001-2003 Free Software Foundation, Inc.
   3    Written by Bruno Haible <haible@clisp.cons.org>, 2001.
   4
   5    This program is free software; you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 2, or (at your option)
   8    any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program; if not, write to the Free Software Foundation,
  17    Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  18
  19
  20 #ifdef HAVE_CONFIG_H
  21 # include "config.h"
  22 #endif
  23
  24 /* Specification.  */
  25 #include "copy-file.h"
  26
  27 #include <errno.h>
  28 #include <fcntl.h>
  29 #include <stddef.h>
  30 #include <sys/stat.h>
  31
  32 #ifdef HAVE_UNISTD_H
  33 # include <unistd.h>
  34 #endif
  35
  36 #if HAVE_UTIME || HAVE_UTIMES
  37 # if HAVE_UTIME_H
  38 #  include <utime.h>
  39 # else
  40 #  include <sys/utime.h>
  41 # endif
  42 #endif
  43
  44 #include "error.h"
  45 #include "safe-read.h"
  46 #include "full-write.h"
  47 #include "binary-io.h"
  48 #include "exit.h"
  49 #include "gettext.h"
  50
  51 #define _(str) gettext (str)
  52
  53 void
  54 copy_file_preserving (const char *src_filename, const char *dest_filename)
  55 {
  56   int src_fd;
  57   struct stat statbuf;
  58   int mode;
  59   int dest_fd;
  60   char buf[4096];
  61   const size_t buf_size = sizeof (buf);
  62
  63   src_fd = open (src_filename, O_RDONLY | O_BINARY);
  64   if (src_fd < 0 || fstat (src_fd, &statbuf) < 0)
  65     error (EXIT_FAILURE, errno, _("error while opening \"%s\" for reading"),
  66            src_filename);
  67
  68   mode = statbuf.st_mode & 07777;
  69
  70   dest_fd = open (dest_filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0600);
  71   if (dest_fd < 0)
  72     error (EXIT_FAILURE, errno, _("cannot open backup file \"%s\" for writing"),
  73            dest_filename);
  74
  75   /* Copy the file contents.  */
  76   for (;;)
  77     {
  78       size_t n_read = safe_read (src_fd, buf, buf_size);
  79       if (n_read == SAFE_READ_ERROR)
  80         error (EXIT_FAILURE, errno, _("error reading \"%s\""), src_filename);
  81       if (n_read == 0)
  82         break;
  83
  84       if (full_write (dest_fd, buf, n_read) < n_read)
  85         error (EXIT_FAILURE, errno, _("error writing \"%s\""), dest_filename);
  86     }
  87
  88   if (close (dest_fd) < 0)
  89     error (EXIT_FAILURE, errno, _("error writing \"%s\""), dest_filename);
  90   if (close (src_fd) < 0)
  91     error (EXIT_FAILURE, errno, _("error after reading \"%s\""), src_filename);
  92
  93   /* Preserve the access and modification times.  */
  94 #if HAVE_UTIME
  95   {
  96     struct utimbuf ut;
  97
  98     ut.actime = statbuf.st_atime;
  99     ut.modtime = statbuf.st_mtime;
 100     utime (dest_filename, &ut);
 101   }
 102 #elif HAVE_UTIMES
 103   {
 104     struct timeval ut[2];
 105
 106     ut[0].tv_sec = statbuf.st_atime; ut[0].tv_usec = 0;
 107     ut[1].tv_sec = statbuf.st_mtime; ut[1].tv_usec = 0;
 108     utimes (dest_filename, &ut);
 109   }
 110 #endif
 111
 112 #if HAVE_CHOWN
 113   /* Preserve the owner and group.  */
 114   chown (dest_filename, statbuf.st_uid, statbuf.st_gid);
 115 #endif
 116
 117   /* Preserve the access permissions.  */
 118   chmod (dest_filename, mode);
 119 }