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, int dir);
  69
  70   int dummy_func (const char *filename __attribute__ ((unused)),
  71                   int dir __attribute__ ((unused)))
  72     {
  73       return 1;
  74     }
  75
  76   if (device->disk)
  77     {
  78       /* Make it sure not to have an infinite recursive calls.  */
  79       static int count = 0;
  80
  81       for (p = grub_fs_list; p; p = p->next)
  82         {
  83           grub_dprintf ("fs", "Detecting %s...\n", p->name);
  84           (p->dir) (device, "/", dummy_func);
  85           if (grub_errno == GRUB_ERR_NONE)
  86             return p;
  87
  88           grub_error_push ();
  89           grub_dprintf ("fs", "%s detection failed.\n", p->name);
  90           grub_error_pop ();
  91
  92           if (grub_errno != GRUB_ERR_BAD_FS)
  93             return 0;
  94
  95           grub_errno = GRUB_ERR_NONE;
  96         }
  97
  98       /* Let's load modules automatically.  */
  99       if (grub_fs_autoload_hook && count == 0)
 100         {
 101           count++;
 102
 103           while (grub_fs_autoload_hook ())
 104             {
 105               p = grub_fs_list;
 106
 107               (p->dir) (device, "/", dummy_func);
 108               if (grub_errno == GRUB_ERR_NONE)
 109                 {
 110                   count--;
 111                   return p;
 112                 }
 113
 114               if (grub_errno != GRUB_ERR_BAD_FS)
 115                 {
 116                   count--;
 117                   return 0;
 118                 }
 119
 120               grub_errno = GRUB_ERR_NONE;
 121             }
 122
 123           count--;
 124         }
 125     }
 126   else if (device->net->fs)
 127     return device->net->fs;
 128
 129   grub_error (GRUB_ERR_UNKNOWN_FS, "unknown filesystem");
 130   return 0;
 131 }
 132
 133 \f
 134
 135 /* Block list support routines.  */
 136
 137 struct grub_fs_block
 138 {
 139   grub_disk_addr_t offset;
 140   unsigned long length;
 141 };
 142
 143 static grub_err_t
 144 grub_fs_blocklist_open (grub_file_t file, const char *name)
 145 {
 146   char *p = (char *) name;
 147   unsigned num = 0;
 148   unsigned i;
 149   grub_disk_t disk = file->device->disk;
 150   struct grub_fs_block *blocks;
 151
 152   /* First, count the number of blocks.  */
 153   do
 154     {
 155       num++;
 156       p = grub_strchr (p, ',');
 157       if (p)
 158         p++;
 159     }
 160   while (p);
 161
 162   /* Allocate a block list.  */
 163   blocks = grub_malloc (sizeof (struct grub_fs_block) * (num + 1));
 164   if (! blocks)
 165     return 0;
 166
 167   file->size = 0;
 168   p = (char *) name;
 169   for (i = 0; i < num; i++)
 170     {
 171       if (*p != '+')
 172         {
 173           blocks[i].offset = grub_strtoull (p, &p, 0);
 174           if (grub_errno != GRUB_ERR_NONE || *p != '+')
 175             {
 176               grub_error (GRUB_ERR_BAD_FILENAME,
 177                           "invalid file name `%s'", name);
 178               goto fail;
 179             }
 180         }
 181       else
 182         blocks[i].offset = 0;
 183
 184       p++;
 185       blocks[i].length = grub_strtoul (p, &p, 0);
 186       if (grub_errno != GRUB_ERR_NONE
 187           || blocks[i].length == 0
 188           || (*p && *p != ',' && ! grub_isspace (*p)))
 189         {
 190           grub_error (GRUB_ERR_BAD_FILENAME,
 191                       "invalid file name `%s'", name);
 192           goto fail;
 193         }
 194
 195       if (disk->total_sectors < blocks[i].offset + blocks[i].length)
 196         {
 197           grub_error (GRUB_ERR_BAD_FILENAME, "beyond the total sectors");
 198           goto fail;
 199         }
 200
 201       file->size += (blocks[i].length << GRUB_DISK_SECTOR_BITS);
 202       p++;
 203     }
 204
 205   blocks[i].length = 0;
 206   file->data = blocks;
 207
 208   return GRUB_ERR_NONE;
 209
 210  fail:
 211   grub_free (blocks);
 212   return grub_errno;
 213 }
 214
 215 static grub_ssize_t
 216 grub_fs_blocklist_read (grub_file_t file, char *buf, grub_size_t len)
 217 {
 218   struct grub_fs_block *p;
 219   grub_disk_addr_t sector;
 220   grub_off_t offset;
 221   grub_ssize_t ret = 0;
 222
 223   if (len > file->size - file->offset)
 224     len = file->size - file->offset;
 225
 226   sector = (file->offset >> GRUB_DISK_SECTOR_BITS);
 227   offset = (file->offset & (GRUB_DISK_SECTOR_SIZE - 1));
 228   for (p = file->data; p->length && len > 0; p++)
 229     {
 230       if (sector < p->length)
 231         {
 232           grub_size_t size;
 233
 234           size = len;
 235           if (((size + offset + GRUB_DISK_SECTOR_SIZE - 1)
 236                >> GRUB_DISK_SECTOR_BITS) > p->length - sector)
 237             size = ((p->length - sector) << GRUB_DISK_SECTOR_BITS) - offset;
 238
 239           if (grub_disk_read (file->device->disk, p->offset + sector, offset,
 240                               size, buf) != GRUB_ERR_NONE)
 241             return -1;
 242
 243           ret += size;
 244           len -= size;
 245           sector -= ((size + offset) >> GRUB_DISK_SECTOR_BITS);
 246           offset = ((size + offset) & (GRUB_DISK_SECTOR_SIZE - 1));
 247         }
 248       else
 249         sector -= p->length;
 250     }
 251
 252   return ret;
 253 }
 254
 255 struct grub_fs grub_fs_blocklist =
 256   {
 257     .name = "blocklist",
 258     .dir = 0,
 259     .open = grub_fs_blocklist_open,
 260     .read = grub_fs_blocklist_read,
 261     .close = 0,
 262     .next = 0
 263   };