kern/fs.c

   1 /* fs.c - filesystem manager */
   2 /*
   3  *  GRUB  --  GRand Unified Bootloader
   4  *  Copyright (C) 2002,2005,2007  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/disk.h>
  21 #include <grub/net.h>
  22 #include <grub/fs.h>
  23 #include <grub/file.h>
  24 #include <grub/err.h>
  25 #include <grub/misc.h>
  26 #include <grub/types.h>
  27 #include <grub/mm.h>
  28 #include <grub/term.h>
  29
  30 static grub_fs_t grub_fs_list;
  31
  32 grub_fs_autoload_hook_t grub_fs_autoload_hook = 0;
  33
  34 void
  35 grub_fs_register (grub_fs_t fs)
  36 {
  37   fs->next = grub_fs_list;
  38   grub_fs_list = fs;
  39 }
  40
  41 void
  42 grub_fs_unregister (grub_fs_t fs)
  43 {
  44   grub_fs_t *p, q;
  45
  46   for (p = &grub_fs_list, q = *p; q; p = &(q->next), q = q->next)
  47     if (q == fs)
  48       {
  49         *p = q->next;
  50         break;
  51       }
  52 }
  53
  54 void
  55 grub_fs_iterate (int (*hook) (const grub_fs_t fs))
  56 {
  57   grub_fs_t p;
  58
  59   for (p = grub_fs_list; p; p = p->next)
  60     if (hook (p))
  61       break;
  62 }
  63
  64 grub_fs_t
  65 grub_fs_probe (grub_device_t device)
  66 {
  67   grub_fs_t p;
  68   auto int dummy_func (const char *filename,
  69                        const struct grub_dirhook_info *info);
  70
  71   int dummy_func (const char *filename __attribute__ ((unused)),
  72                   const struct grub_dirhook_info *info  __attribute__ ((unused)))
  73     {
  74       return 1;
  75     }
  76
  77   if (device->disk)
  78     {
  79       /* Make it sure not to have an infinite recursive calls.  */
  80       static int count = 0;
  81
  82       for (p = grub_fs_list; p; p = p->next)
  83         {
  84           grub_dprintf ("fs", "Detecting %s...\n", p->name);
  85           (p->dir) (device, "/", dummy_func);
  86           if (grub_errno == GRUB_ERR_NONE)
  87             return p;
  88
  89           grub_error_push ();
  90           grub_dprintf ("fs", "%s detection failed.\n", p->name);
  91           grub_error_pop ();
  92
  93           if (grub_errno != GRUB_ERR_BAD_FS)
  94             return 0;
  95
  96           grub_errno = GRUB_ERR_NONE;
  97         }
  98
  99       /* Let's load modules automatically.  */
 100       if (grub_fs_autoload_hook && count == 0)
 101         {
 102           count++;
 103
 104           while (grub_fs_autoload_hook ())
 105             {
 106               p = grub_fs_list;
 107
 108               (p->dir) (device, "/", dummy_func);
 109               if (grub_errno == GRUB_ERR_NONE)
 110                 {
 111                   count--;
 112                   return p;
 113                 }
 114
 115               if (grub_errno != GRUB_ERR_BAD_FS)
 116                 {
 117                   count--;
 118                   return 0;
 119                 }
 120
 121               grub_errno = GRUB_ERR_NONE;
 122             }
 123
 124           count--;
 125         }
 126     }
 127   else if (device->net->fs)
 128     return device->net->fs;
 129
 130   grub_error (GRUB_ERR_UNKNOWN_FS, "unknown filesystem");
 131   return 0;
 132 }
 133
 134 \f
 135
 136 /* Block list support routines.  */
 137
 138 struct grub_fs_block
 139 {
 140   grub_disk_addr_t offset;
 141   unsigned long length;
 142 };
 143
 144 static grub_err_t
 145 grub_fs_blocklist_open (grub_file_t file, const char *name)
 146 {
 147   char *p = (char *) name;
 148   unsigned num = 0;
 149   unsigned i;
 150   grub_disk_t disk = file->device->disk;
 151   struct grub_fs_block *blocks;
 152
 153   /* First, count the number of blocks.  */
 154   do
 155     {
 156       num++;
 157       p = grub_strchr (p, ',');
 158       if (p)
 159         p++;
 160     }
 161   while (p);
 162
 163   /* Allocate a block list.  */
 164   blocks = grub_zalloc (sizeof (struct grub_fs_block) * (num + 1));
 165   if (! blocks)
 166     return 0;
 167
 168   file->size = 0;
 169   p = (char *) name;
 170   for (i = 0; i < num; i++)
 171     {
 172       if (*p != '+')
 173         {
 174           blocks[i].offset = grub_strtoull (p, &p, 0);
 175           if (grub_errno != GRUB_ERR_NONE || *p != '+')
 176             {
 177               grub_error (GRUB_ERR_BAD_FILENAME,
 178                           "invalid file name `%s'", name);
 179               goto fail;
 180             }
 181         }
 182
 183       p++;
 184       blocks[i].length = grub_strtoul (p, &p, 0);
 185       if (grub_errno != GRUB_ERR_NONE
 186           || blocks[i].length == 0
 187           || (*p && *p != ',' && ! grub_isspace (*p)))
 188         {
 189           grub_error (GRUB_ERR_BAD_FILENAME,
 190                       "invalid file name `%s'", name);
 191           goto fail;
 192         }
 193
 194       if (disk->total_sectors < blocks[i].offset + blocks[i].length)
 195         {
 196           grub_error (GRUB_ERR_BAD_FILENAME, "beyond the total sectors");
 197           goto fail;
 198         }
 199
 200       file->size += (blocks[i].length << GRUB_DISK_SECTOR_BITS);
 201       p++;
 202     }
 203
 204   file->data = blocks;
 205
 206   return GRUB_ERR_NONE;
 207
 208  fail:
 209   grub_free (blocks);
 210   return grub_errno;
 211 }
 212
 213 static grub_ssize_t
 214 grub_fs_blocklist_read (grub_file_t file, char *buf, grub_size_t len)
 215 {
 216   struct grub_fs_block *p;
 217   grub_disk_addr_t sector;
 218   grub_off_t offset;
 219   grub_ssize_t ret = 0;
 220
 221   if (len > file->size - file->offset)
 222     len = file->size - file->offset;
 223
 224   sector = (file->offset >> GRUB_DISK_SECTOR_BITS);
 225   offset = (file->offset & (GRUB_DISK_SECTOR_SIZE - 1));
 226   for (p = file->data; p->length && len > 0; p++)
 227     {
 228       if (sector < p->length)
 229         {
 230           grub_size_t size;
 231
 232           size = len;
 233           if (((size + offset + GRUB_DISK_SECTOR_SIZE - 1)
 234                >> GRUB_DISK_SECTOR_BITS) > p->length - sector)
 235             size = ((p->length - sector) << GRUB_DISK_SECTOR_BITS) - offset;
 236
 237           if (grub_disk_read (file->device->disk, p->offset + sector, offset,
 238                               size, buf) != GRUB_ERR_NONE)
 239             return -1;
 240
 241           ret += size;
 242           len -= size;
 243           sector -= ((size + offset) >> GRUB_DISK_SECTOR_BITS);
 244           offset = ((size + offset) & (GRUB_DISK_SECTOR_SIZE - 1));
 245         }
 246       else
 247         sector -= p->length;
 248     }
 249
 250   return ret;
 251 }
 252
 253 struct grub_fs grub_fs_blocklist =
 254   {
 255     .name = "blocklist",
 256     .dir = 0,
 257     .open = grub_fs_blocklist_open,
 258     .read = grub_fs_blocklist_read,
 259     .close = 0,
 260     .next = 0
 261   };