partmap/pc.c

   1 /* pc.c - Read PC style partition tables.  */
   2 /*
   3  *  GRUB  --  GRand Unified Bootloader
   4  *  Copyright (C) 2002,2004,2005,2006,2007,2008,2009  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/partition.h>
  21 #include <grub/pc_partition.h>
  22 #include <grub/disk.h>
  23 #include <grub/mm.h>
  24 #include <grub/misc.h>
  25 #include <grub/dl.h>
  26
  27 static struct grub_partition_map grub_pc_partition_map;
  28 \f
  29
  30 /* Parse the partition representation in STR and return a partition.  */
  31 static grub_partition_t
  32 grub_partition_parse (const char *str)
  33 {
  34   grub_partition_t p;
  35   struct grub_pc_partition *pcdata;
  36
  37   char *s = (char *) str;
  38
  39   p = (grub_partition_t) grub_malloc (sizeof (*p));
  40   if (! p)
  41     return 0;
  42
  43   pcdata = (struct grub_pc_partition *) grub_malloc (sizeof (*pcdata));
  44   if (! pcdata)
  45     goto fail;
  46
  47   p->data = pcdata;
  48   p->partmap = &grub_pc_partition_map;
  49
  50   /* Initialize some of the fields with invalid values.  */
  51   pcdata->bsd_part = pcdata->dos_type = pcdata->bsd_type = p->index = -1;
  52
  53   /* Get the DOS partition number. The number is counted from one for
  54      the user interface, and from zero internally.  */
  55   pcdata->dos_part = grub_strtoul (s, &s, 0) - 1;
  56
  57   if (grub_errno)
  58     {
  59       /* Not found. Maybe only a BSD label is specified.  */
  60       pcdata->dos_part = -1;
  61       grub_errno = GRUB_ERR_NONE;
  62     }
  63   else if (*s == ',')
  64     s++;
  65
  66   if (*s)
  67     {
  68       if (*s >= 'a' && *s <= 'h')
  69         {
  70           pcdata->bsd_part = *s - 'a';
  71           s++;
  72         }
  73
  74       if (*s)
  75         goto fail;
  76     }
  77
  78   if (pcdata->dos_part == -1 && pcdata->bsd_part == -1)
  79     goto fail;
  80
  81   return p;
  82
  83  fail:
  84   grub_free (p);
  85   grub_free (pcdata);
  86   grub_error (GRUB_ERR_BAD_FILENAME, "invalid partition");
  87   return 0;
  88 }
  89
  90 static grub_err_t
  91 pc_partition_map_iterate (grub_disk_t disk,
  92                           int (*hook) (grub_disk_t disk,
  93                                        const grub_partition_t partition))
  94 {
  95   struct grub_partition p;
  96   struct grub_pc_partition pcdata;
  97   struct grub_pc_partition_mbr mbr;
  98   struct grub_pc_partition_disk_label label;
  99   struct grub_disk raw;
 100
 101   /* Enforce raw disk access.  */
 102   raw = *disk;
 103   raw.partition = 0;
 104
 105   p.offset = 0;
 106   pcdata.ext_offset = 0;
 107   pcdata.dos_part = -1;
 108   p.data = &pcdata;
 109   p.partmap = &grub_pc_partition_map;
 110
 111   while (1)
 112     {
 113       int i;
 114       struct grub_pc_partition_entry *e;
 115
 116       /* Read the MBR.  */
 117       if (grub_disk_read (&raw, p.offset, 0, sizeof (mbr), &mbr))
 118         goto finish;
 119
 120       /* Check if it is valid.  */
 121       if (mbr.signature != grub_cpu_to_le16 (GRUB_PC_PARTITION_SIGNATURE))
 122         return grub_error (GRUB_ERR_BAD_PART_TABLE, "no signature");
 123
 124       /* Analyze DOS partitions.  */
 125       for (p.index = 0; p.index < 4; p.index++)
 126         {
 127           e = mbr.entries + p.index;
 128
 129           p.start = p.offset + grub_le_to_cpu32 (e->start);
 130           p.len = grub_le_to_cpu32 (e->length);
 131           pcdata.bsd_part = -1;
 132           pcdata.dos_type = e->type;
 133           pcdata.bsd_type = -1;
 134
 135           grub_dprintf ("partition",
 136                         "partition %d: flag 0x%x, type 0x%x, start 0x%llx, len 0x%llx\n",
 137                         p.index, e->flag, pcdata.dos_type,
 138                         (unsigned long long) p.start,
 139                         (unsigned long long) p.len);
 140
 141           /* If this is a GPT partition, this MBR is just a dummy.  */
 142           if (e->type == GRUB_PC_PARTITION_TYPE_GPT_DISK && p.index == 0)
 143             return grub_error (GRUB_ERR_BAD_PART_TABLE, "dummy mbr");
 144
 145           /* If this partition is a normal one, call the hook.  */
 146           if (! grub_pc_partition_is_empty (e->type)
 147               && ! grub_pc_partition_is_extended (e->type))
 148             {
 149               pcdata.dos_part++;
 150
 151               if (hook (disk, &p))
 152                 return 1;
 153
 154               /* Check if this is a BSD partition.  */
 155               if (grub_pc_partition_is_bsd (e->type))
 156                 {
 157                   /* Check if the BSD label is within the DOS partition.  */
 158                   if (p.len <= GRUB_PC_PARTITION_BSD_LABEL_SECTOR)
 159                     {
 160                       grub_dprintf ("partition", "no space for disk label\n");
 161                       continue;
 162                     }
 163                   /* Read the BSD label.  */
 164                   if (grub_disk_read (&raw,
 165                                       (p.start
 166                                        + GRUB_PC_PARTITION_BSD_LABEL_SECTOR),
 167                                       0,
 168                                       sizeof (label),
 169                                       &label))
 170                     goto finish;
 171
 172                   /* Check if it is valid.  */
 173                   if (label.magic
 174                       != grub_cpu_to_le32 (GRUB_PC_PARTITION_BSD_LABEL_MAGIC))
 175                     {
 176                       grub_dprintf ("partition",
 177                                     "invalid disk label magic 0x%x on partition %d\n",
 178                                     label.magic, p.index);
 179                       continue;
 180                     }
 181                   for (pcdata.bsd_part = 0;
 182                        pcdata.bsd_part < grub_cpu_to_le16 (label.num_partitions);
 183                        pcdata.bsd_part++)
 184                     {
 185                       struct grub_pc_partition_bsd_entry *be
 186                         = label.entries + pcdata.bsd_part;
 187
 188                       p.start = grub_le_to_cpu32 (be->offset);
 189                       p.len = grub_le_to_cpu32 (be->size);
 190                       pcdata.bsd_type = be->fs_type;
 191
 192                       if (be->fs_type != GRUB_PC_PARTITION_BSD_TYPE_UNUSED)
 193                         if (hook (disk, &p))
 194                           return 1;
 195                     }
 196                 }
 197             }
 198           else if (pcdata.dos_part < 4)
 199             /* If this partition is a logical one, shouldn't increase the
 200                partition number.  */
 201             pcdata.dos_part++;
 202         }
 203
 204       /* Find an extended partition.  */
 205       for (i = 0; i < 4; i++)
 206         {
 207           e = mbr.entries + i;
 208
 209           if (grub_pc_partition_is_extended (e->type))
 210             {
 211               p.offset = pcdata.ext_offset + grub_le_to_cpu32 (e->start);
 212               if (! pcdata.ext_offset)
 213                 pcdata.ext_offset = p.offset;
 214
 215               break;
 216             }
 217         }
 218
 219       /* If no extended partition, the end.  */
 220       if (i == 4)
 221         break;
 222     }
 223
 224  finish:
 225   return grub_errno;
 226 }
 227
 228
 229 static grub_partition_t
 230 pc_partition_map_probe (grub_disk_t disk, const char *str)
 231 {
 232   grub_partition_t p;
 233   struct grub_pc_partition *pcdata;
 234
 235   auto int find_func (grub_disk_t d, const grub_partition_t partition);
 236
 237   int find_func (grub_disk_t d __attribute__ ((unused)),
 238                  const grub_partition_t partition)
 239     {
 240       struct grub_pc_partition *partdata = partition->data;
 241
 242       if ((pcdata->dos_part == partdata->dos_part || pcdata->dos_part == -1)
 243           && pcdata->bsd_part == partdata->bsd_part)
 244         {
 245           grub_memcpy (p, partition, sizeof (*p));
 246           p->data = pcdata;
 247           grub_memcpy (pcdata, partdata, sizeof (*pcdata));
 248           return 1;
 249         }
 250
 251       return 0;
 252     }
 253
 254   p = grub_partition_parse (str);
 255   if (! p)
 256     return 0;
 257
 258   pcdata = p->data;
 259   pc_partition_map_iterate (disk, find_func);
 260   if (grub_errno)
 261     goto fail;
 262
 263   if (p->index < 0)
 264     {
 265       grub_error (GRUB_ERR_BAD_DEVICE, "no such partition");
 266       goto fail;
 267     }
 268
 269   return p;
 270
 271  fail:
 272   grub_free (p);
 273   grub_free (pcdata);
 274   return 0;
 275 }
 276
 277
 278 static char *
 279 pc_partition_map_get_name (const grub_partition_t p)
 280 {
 281   char *name;
 282   struct grub_pc_partition *pcdata = p->data;
 283
 284   name = grub_malloc (13);
 285   if (! name)
 286     return 0;
 287
 288   if (pcdata->bsd_part < 0)
 289     grub_sprintf (name, "%d", pcdata->dos_part + 1);
 290   else if (pcdata->dos_part < 0)
 291     grub_sprintf (name, "%c", pcdata->bsd_part + 'a');
 292   else
 293     grub_sprintf (name, "%d,%c", pcdata->dos_part + 1, pcdata->bsd_part + 'a');
 294
 295   return name;
 296 }
 297
 298 \f
 299 /* Partition map type.  */
 300 static struct grub_partition_map grub_pc_partition_map =
 301   {
 302     .name = "pc_partition_map",
 303     .iterate = pc_partition_map_iterate,
 304     .probe = pc_partition_map_probe,
 305     .get_name = pc_partition_map_get_name
 306   };
 307
 308 GRUB_MOD_INIT(pc_partition_map)
 309 {
 310   grub_partition_map_register (&grub_pc_partition_map);
 311 }
 312
 313 GRUB_MOD_FINI(pc_partition_map)
 314 {
 315   grub_partition_map_unregister (&grub_pc_partition_map);
 316 }