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