arch/common/boot/grub2/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
  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, int dir))
  61 {
  62   DIR *dir;
  63
  64   /* Check if the disk is our dummy disk.  */
  65   if (grub_strcmp (device->disk->name, "host"))
  66     return grub_error (GRUB_ERR_BAD_FS, "not a hostfs");
  67
  68   dir = opendir (path);
  69   if (! dir)
  70     return grub_error (GRUB_ERR_BAD_FILENAME,
  71                        "can't open the hostfs directory `%s'", path);
  72
  73   while (1)
  74     {
  75       struct dirent *de;
  76
  77       de = readdir (dir);
  78       if (! de)
  79         break;
  80
  81 #ifdef DT_DIR
  82       hook (de->d_name, de->d_type == DT_DIR);
  83 #else
  84       hook (de->d_name, is_dir (path, de->d_name));
  85 #endif
  86     }
  87
  88   closedir (dir);
  89
  90   return GRUB_ERR_NONE;
  91 }
  92
  93 /* Open a file named NAME and initialize FILE.  */
  94 static grub_err_t
  95 grub_hostfs_open (struct grub_file *file, const char *name)
  96 {
  97   FILE *f;
  98
  99   f = fopen (name, "rb");
 100   if (! f)
 101     return grub_error (GRUB_ERR_BAD_FILENAME,
 102                        "can't open `%s'", name);
 103   file->data = f;
 104
 105 #ifdef __MINGW32__
 106   file->size = grub_util_get_disk_size (name);
 107 #else
 108   fseeko (f, 0, SEEK_END);
 109   file->size = ftello (f);
 110   fseeko (f, 0, SEEK_SET);
 111 #endif
 112
 113   return GRUB_ERR_NONE;
 114 }
 115
 116 static grub_ssize_t
 117 grub_hostfs_read (grub_file_t file, char *buf, grub_size_t len)
 118 {
 119   FILE *f;
 120
 121   f = (FILE *) file->data;
 122   fseeko (f, file->offset, SEEK_SET);
 123   int s = fread (buf, 1, len, f);
 124
 125   return s;
 126 }
 127
 128 static grub_err_t
 129 grub_hostfs_close (grub_file_t file)
 130 {
 131   FILE *f;
 132
 133   f = (FILE *) file->data;
 134   fclose (f);
 135
 136   return GRUB_ERR_NONE;
 137 }
 138
 139 static grub_err_t
 140 grub_hostfs_label (grub_device_t device __attribute ((unused)),
 141                    char **label __attribute ((unused)))
 142 {
 143   *label = 0;
 144   return GRUB_ERR_NONE;
 145 }
 146
 147 static struct grub_fs grub_hostfs_fs =
 148   {
 149     .name = "hostfs",
 150     .dir = grub_hostfs_dir,
 151     .open = grub_hostfs_open,
 152     .read = grub_hostfs_read,
 153     .close = grub_hostfs_close,
 154     .label = grub_hostfs_label,
 155     .next = 0
 156   };
 157
 158 \f
 159
 160 GRUB_MOD_INIT(hostfs)
 161 {
 162   grub_fs_register (&grub_hostfs_fs);
 163 }
 164
 165 GRUB_MOD_FINI(hostfs)
 166 {
 167   grub_fs_unregister (&grub_hostfs_fs);
 168 }