util/hostfs.c

   1 /* hostfs.c - Dummy filesystem to provide access to the hosts filesystem  */
   2 /*
   3  *  GRUB  --  GRand Unified Bootloader
   4  *  Copyright (C) 2007,2008  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 #define _BSD_SOURCE
  20 #include <grub/fs.h>
  21 #include <grub/file.h>
  22 #include <grub/disk.h>
  23 #include <grub/misc.h>
  24 #include <grub/dl.h>
  25 #include <grub/util/misc.h>
  26
  27 #include <dirent.h>
  28 #include <stdio.h>
  29
  30
  31 #ifndef DT_DIR
  32 /* dirent.d_type is a BSD extension, not part of POSIX */
  33 #include <sys/stat.h>
  34 #include <string.h>
  35
  36 static int
  37 is_dir (const char *path, const char *name)
  38 {
  39   int len1 = strlen(path);
  40   int len2 = strlen(name);
  41
  42   char pathname[len1 + 1 + len2 + 1 + 13];
  43   strcpy (pathname, path);
  44
  45   /* Avoid UNC-path "//name" on Cygwin.  */
  46   if (len1 > 0 && pathname[len1 - 1] != '/')
  47     strcat (pathname, "/");
  48
  49   strcat (pathname, name);
  50
  51   struct stat st;
  52   if (stat (pathname, &st))
  53     return 0;
  54   return S_ISDIR (st.st_mode);
  55 }
  56 #endif
  57
  58 static grub_err_t
  59 grub_hostfs_dir (grub_device_t device, const char *path,
  60                  int (*hook) (const char *filename,
  61                               const struct grub_dirhook_info *info))
  62 {
  63   DIR *dir;
  64
  65   /* Check if the disk is our dummy disk.  */
  66   if (grub_strcmp (device->disk->name, "host"))
  67     return grub_error (GRUB_ERR_BAD_FS, "not a hostfs");
  68
  69   dir = opendir (path);
  70   if (! dir)
  71     return grub_error (GRUB_ERR_BAD_FILENAME,
  72                        "can't open the hostfs directory `%s'", path);
  73
  74   while (1)
  75     {
  76       struct dirent *de;
  77       struct grub_dirhook_info info;
  78       grub_memset (&info, 0, sizeof (info));
  79
  80       de = readdir (dir);
  81       if (! de)
  82         break;
  83
  84 #ifdef DT_DIR
  85       info.dir = (de->d_type == DT_DIR);
  86 #else
  87       info.dir = !! is_dir (path, de->d_name);
  88 #endif
  89       hook (de->d_name, &info);
  90
  91     }
  92
  93   closedir (dir);
  94
  95   return GRUB_ERR_NONE;
  96 }
  97
  98 /* Open a file named NAME and initialize FILE.  */
  99 static grub_err_t
 100 grub_hostfs_open (struct grub_file *file, const char *name)
 101 {
 102   FILE *f;
 103
 104   f = fopen (name, "rb");
 105   if (! f)
 106     return grub_error (GRUB_ERR_BAD_FILENAME,
 107                        "can't open `%s'", name);
 108   file->data = f;
 109
 110 #ifdef __MINGW32__
 111   file->size = grub_util_get_disk_size (name);
 112 #else
 113   fseeko (f, 0, SEEK_END);
 114   file->size = ftello (f);
 115   fseeko (f, 0, SEEK_SET);
 116 #endif
 117
 118   return GRUB_ERR_NONE;
 119 }
 120
 121 static grub_ssize_t
 122 grub_hostfs_read (grub_file_t file, char *buf, grub_size_t len)
 123 {
 124   FILE *f;
 125
 126   f = (FILE *) file->data;
 127   fseeko (f, file->offset, SEEK_SET);
 128   int s = fread (buf, 1, len, f);
 129
 130   return s;
 131 }
 132
 133 static grub_err_t
 134 grub_hostfs_close (grub_file_t file)
 135 {
 136   FILE *f;
 137
 138   f = (FILE *) file->data;
 139   fclose (f);
 140
 141   return GRUB_ERR_NONE;
 142 }
 143
 144 static grub_err_t
 145 grub_hostfs_label (grub_device_t device __attribute ((unused)),
 146                    char **label __attribute ((unused)))
 147 {
 148   *label = 0;
 149   return GRUB_ERR_NONE;
 150 }
 151
 152 static struct grub_fs grub_hostfs_fs =
 153   {
 154     .name = "hostfs",
 155     .dir = grub_hostfs_dir,
 156     .open = grub_hostfs_open,
 157     .read = grub_hostfs_read,
 158     .close = grub_hostfs_close,
 159     .label = grub_hostfs_label,
 160     .next = 0
 161   };
 162
 163 \f
 164
 165 GRUB_MOD_INIT(hostfs)
 166 {
 167   grub_fs_register (&grub_hostfs_fs);
 168 }
 169
 170 GRUB_MOD_FINI(hostfs)
 171 {
 172   grub_fs_unregister (&grub_hostfs_fs);
 173 }