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
  26 #include <dirent.h>
  27 #include <stdio.h>
  28
  29
  30 #ifndef DT_DIR
  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 #endif
  56
  57 static grub_err_t
  58 grub_hostfs_dir (grub_device_t device, const char *path,
  59                  int (*hook) (const char *filename, int dir))
  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
  76       de = readdir (dir);
  77       if (! de)
  78         break;
  79
  80 #ifdef DT_DIR
  81       hook (de->d_name, de->d_type == DT_DIR);
  82 #else
  83       hook (de->d_name, is_dir (path, de->d_name));
  84 #endif
  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, "r");
  99   if (! f)
 100     return grub_error (GRUB_ERR_BAD_FILENAME,
 101                        "can't open `%s'", name);
 102   file->data = f;
 103
 104   fseeko (f, 0, SEEK_END);
 105   file->size = ftello (f);
 106   fseeko (f, 0, SEEK_SET);
 107
 108   return GRUB_ERR_NONE;
 109 }
 110
 111 static grub_ssize_t
 112 grub_hostfs_read (grub_file_t file, char *buf, grub_size_t len)
 113 {
 114   FILE *f;
 115
 116   f = (FILE *) file->data;
 117   fseeko (f, file->offset, SEEK_SET);
 118   int s = fread (buf, 1, len, f);
 119
 120   return s;
 121 }
 122
 123 static grub_err_t
 124 grub_hostfs_close (grub_file_t file)
 125 {
 126   FILE *f;
 127
 128   f = (FILE *) file->data;
 129   fclose (f);
 130
 131   return GRUB_ERR_NONE;
 132 }
 133
 134 static grub_err_t
 135 grub_hostfs_label (grub_device_t device __attribute ((unused)),
 136                    char **label __attribute ((unused)))
 137 {
 138   *label = 0;
 139   return GRUB_ERR_NONE;
 140 }
 141
 142 static struct grub_fs grub_hostfs_fs =
 143   {
 144     .name = "hostfs",
 145     .dir = grub_hostfs_dir,
 146     .open = grub_hostfs_open,
 147     .read = grub_hostfs_read,
 148     .close = grub_hostfs_close,
 149     .label = grub_hostfs_label,
 150     .next = 0
 151   };
 152
 153 \f
 154
 155 GRUB_MOD_INIT(hostfs)
 156 {
 157   grub_fs_register (&grub_hostfs_fs);
 158 }
 159
 160 GRUB_MOD_FINI(hostfs)
 161 {
 162   grub_fs_unregister (&grub_hostfs_fs);
 163 }