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 #if !defined(_WIN32)
  32 #include <libgen.h>
  33 #endif
  34
  35 #define DEFAULT_ENVBLK_SIZE     1024
  36 #define GRUB_ENVBLK_MESSAGE     "# WARNING: Do not edit this file by tools other than "PACKAGE"-editenv!!!\n"
  37
  38 void
  39 grub_util_create_envblk_file (const char *name)
  40 {
  41   FILE *fp;
  42   char *buf, *pbuf, *namenew;
  43 #if !defined(_WIN32)
  44   ssize_t size = 1;
  45   char *rename_target = xstrdup (name);
  46   int rc;
  47 #endif
  48
  49   buf = xmalloc (DEFAULT_ENVBLK_SIZE);
  50
  51   namenew = xasprintf ("%s.new", name);
  52   fp = grub_util_fopen (namenew, "wb");
  53   if (! fp)
  54     grub_util_error (_("cannot open `%s': %s"), namenew,
  55                      strerror (errno));
  56
  57   pbuf = buf;
  58   memcpy (pbuf, GRUB_ENVBLK_SIGNATURE, sizeof (GRUB_ENVBLK_SIGNATURE) - 1);
  59   pbuf += sizeof (GRUB_ENVBLK_SIGNATURE) - 1;
  60   memcpy (pbuf, GRUB_ENVBLK_MESSAGE, sizeof (GRUB_ENVBLK_MESSAGE) - 1);
  61   pbuf += sizeof (GRUB_ENVBLK_MESSAGE) - 1;
  62   memset (pbuf , '#',
  63           DEFAULT_ENVBLK_SIZE - sizeof (GRUB_ENVBLK_SIGNATURE) - sizeof (GRUB_ENVBLK_MESSAGE) + 2);
  64
  65   if (fwrite (buf, 1, DEFAULT_ENVBLK_SIZE, fp) != DEFAULT_ENVBLK_SIZE)
  66     grub_util_error (_("cannot write to `%s': %s"), namenew,
  67                      strerror (errno));
  68
  69
  70   if (grub_util_file_sync (fp) < 0)
  71     grub_util_error (_("cannot sync `%s': %s"), namenew, strerror (errno));
  72   free (buf);
  73   fclose (fp);
  74
  75 #if defined(_WIN32)
  76   if (grub_util_rename (namenew, name) < 0)
  77     grub_util_error (_("cannot rename the file %s to %s"), namenew, name);
  78 #else
  79   while (1)
  80     {
  81       char *linkbuf;
  82       ssize_t retsize;
  83
  84       linkbuf = xmalloc (size + 1);
  85       retsize = grub_util_readlink (rename_target, linkbuf, size);
  86       if (retsize < 0 && (errno == ENOENT || errno == EINVAL))
  87         {
  88           free (linkbuf);
  89           break;
  90         }
  91       else if (retsize < 0)
  92         {
  93           free (linkbuf);
  94           grub_util_error (_("cannot rename the file %s to %s: %m"), namenew, name);
  95         }
  96       else if (retsize == size)
  97         {
  98           free (linkbuf);
  99           size += 128;
 100           continue;
 101         }
 102
 103       linkbuf[retsize] = '\0';
 104       if (linkbuf[0] == '/')
 105         {
 106           free (rename_target);
 107           rename_target = linkbuf;
 108         }
 109       else
 110         {
 111           char *dbuf = xstrdup (rename_target);
 112           const char *dir = dirname (dbuf);
 113
 114           free (rename_target);
 115           rename_target = xasprintf ("%s/%s", dir, linkbuf);
 116           free (dbuf);
 117           free (linkbuf);
 118         }
 119     }
 120
 121   rc = grub_util_rename (namenew, rename_target);
 122   if (rc < 0 && errno == EXDEV)
 123     {
 124       rc = grub_install_copy_file (namenew, rename_target, 1);
 125       grub_util_unlink (namenew);
 126     }
 127
 128   free (rename_target);
 129
 130   if (rc < 0)
 131     grub_util_error (_("cannot rename the file %s to %s: %m"), namenew, name);
 132 #endif
 133
 134   free (namenew);
 135 }