util/editenv.c

   1 /* editenv.c - tool to edit environment block.  */
   2 /*
   3  *  GRUB  --  GRand Unified Bootloader
   4  *  Copyright (C) 2008,2009,2010,2013 Free Software Foundation, Inc.
   5  *
   6  *  GRUB is free software: you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation, either version 3 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  GRUB is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <config.h>
  21 #include <grub/types.h>
  22 #include <grub/emu/misc.h>
  23 #include <grub/util/misc.h>
  24 #include <grub/util/install.h>
  25 #include <grub/lib/envblk.h>
  26 #include <grub/i18n.h>
  27 #include <grub/emu/hostfile.h>
  28
  29 #include <errno.h>
  30 #include <string.h>
  31
  32 #define DEFAULT_ENVBLK_SIZE     1024
  33
  34 void
  35 grub_util_create_envblk_file (const char *name)
  36 {
  37   FILE *fp;
  38   char *buf;
  39   char *namenew;
  40
  41   buf = xmalloc (DEFAULT_ENVBLK_SIZE);
  42
  43   namenew = xasprintf ("%s.new", name);
  44   fp = grub_util_fopen (namenew, "wb");
  45   if (! fp)
  46     grub_util_error (_("cannot open `%s': %s"), namenew,
  47                      strerror (errno));
  48
  49   memcpy (buf, GRUB_ENVBLK_SIGNATURE, sizeof (GRUB_ENVBLK_SIGNATURE) - 1);
  50   memset (buf + sizeof (GRUB_ENVBLK_SIGNATURE) - 1, '#',
  51           DEFAULT_ENVBLK_SIZE - sizeof (GRUB_ENVBLK_SIGNATURE) + 1);
  52
  53   if (fwrite (buf, 1, DEFAULT_ENVBLK_SIZE, fp) != DEFAULT_ENVBLK_SIZE)
  54     grub_util_error (_("cannot write to `%s': %s"), namenew,
  55                      strerror (errno));
  56
  57
  58   grub_util_file_sync (fp);
  59   free (buf);
  60   fclose (fp);
  61
  62   if (grub_util_rename (namenew, name) < 0)
  63     grub_util_error (_("cannot rename the file %s to %s"), namenew, name);
  64   free (namenew);
  65 }