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
  29 #ifndef GRUB_UTIL
  30 static grub_dl_t my_mod;
  31 #endif
  32 \f
  33
  34 /* Parse the partition representation in STR and return a partition.  */
  35 static grub_partition_t
  36 grub_partition_parse (const char *str)
  37 {
  38   grub_partition_t p;
  39   struct grub_pc_partition *pcdata;
  40
  41   char *s = (char *) str;
  42
  43   p = (grub_partition_t) grub_malloc (sizeof (*p));
  44   if (! p)
  45     return 0;
  46
  47   pcdata = (struct grub_pc_partition *) grub_malloc (sizeof (*pcdata));
  48   if (! pcdata)
  49     goto fail;
  50
  51   p->data = pcdata;
  52   p->partmap = &grub_pc_partition_map;
  53
  54   /* Initialize some of the fields with invalid values.  */
  55   pcdata->bsd_part = pcdata->dos_type = pcdata->bsd_type = p->index = -1;
  56
  57   /* Get the DOS partition number. The number is counted from one for
  58      the user interface, and from zero internally.  */
  59   pcdata->dos_part = grub_strtoul (s, &s, 0) - 1;
  60
  61   if (grub_errno)
  62     {
  63       /* Not found. Maybe only a BSD label is specified.  */
  64       pcdata->dos_part = -1;
  65       grub_errno = GRUB_ERR_NONE;
  66     }
  67   else if (*s == ',')
  68     s++;
  69
  70   if (*s)
  71     {
  72       if (*s >= 'a' && *s <= 'h')
  73         {
  74           pcdata->bsd_part = *s - 'a';
  75           s++;
  76         }
  77
  78       if (*s)
  79         goto fail;
  80     }
  81
  82   if (pcdata->dos_part == -1 && pcdata->bsd_part == -1)
  83     goto fail;
  84
  85   return p;
  86
  87  fail:
  88   grub_free (p);
  89   grub_free (pcdata);
  90   grub_error (GRUB_ERR_BAD_FILENAME, "invalid partition");
  91   return 0;
  92 }
  93
  94 static grub_err_t
  95 pc_partition_map_iterate (grub_disk_t disk,
  96                           int (*hook) (grub_disk_t disk,
  97                                        const grub_partition_t partition))
  98 {
  99   struct grub_partition p;
 100   struct grub_pc_partition pcdata;
 101   struct grub_pc_partition_mbr mbr;
 102   struct grub_pc_partition_disk_label label;
 103   struct grub_disk raw;
 104
 105   /* Enforce raw disk access.  */
 106   raw = *disk;
 107   raw.partition = 0;
 108
 109   p.offset = 0;
 110   pcdata.ext_offset = 0;
 111   pcdata.dos_part = -1;
 112   p.data = &pcdata;
 113   p.partmap = &grub_pc_partition_map;
 114
 115   while (1)
 116     {
 117       int i;
 118       struct grub_pc_partition_entry *e;
 119
 120       /* Read the MBR.  */
 121       if (grub_disk_read (&raw, p.offset, 0, sizeof (mbr), (char *) &mbr))
 122         goto finish;
 123
 124       /* Check if it is valid.  */
 125       if (mbr.signature != grub_cpu_to_le16 (GRUB_PC_PARTITION_SIGNATURE))
 126         return grub_error (GRUB_ERR_BAD_PART_TABLE, "no signature");
 127
 128       /* Analyze DOS partitions.  */
 129       for (p.index = 0; p.index < 4; p.index++)
 130         {
 131           e = mbr.entries + p.index;
 132
 133           p.start = p.offset + grub_le_to_cpu32 (e->start);
 134           p.len = grub_le_to_cpu32 (e->length);
 135           pcdata.bsd_part = -1;
 136           pcdata.dos_type = e->type;
 137           pcdata.bsd_type = -1;
 138
 139           grub_dprintf ("partition",
 140                         "partition %d: flag 0x%x, type 0x%x, start 0x%llx, len 0x%llx\n",
 141                         p.index, e->flag, pcdata.dos_type,
 142                         (unsigned long long) p.start,
 143                         (unsigned long long) p.len);
 144
 145           /* If this is a GPT partition, this MBR is just a dummy.  */
 146           if (e->type == GRUB_PC_PARTITION_TYPE_GPT_DISK && p.index == 0)
 147             return grub_error (GRUB_ERR_BAD_PART_TABLE, "dummy mbr");
 148
 149           /* If this partition is a normal one, call the hook.  */
 150           if (! grub_pc_partition_is_empty (e->type)
 151               && ! grub_pc_partition_is_extended (e->type))
 152             {
 153               pcdata.dos_part++;
 154
 155               if (hook (disk, &p))
 156                 return 1;
 157
 158               /* Check if this is a BSD partition.  */
 159               if (grub_pc_partition_is_bsd (e->type))
 160                 {
 161                   /* Check if the BSD label is within the DOS partition.  */
 162                   if (p.len <= GRUB_PC_PARTITION_BSD_LABEL_SECTOR)
 163                     {
 164                       grub_dprintf ("partition", "no space for disk label\n");
 165                       continue;
 166                     }
 167                   /* Read the BSD label.  */
 168                   if (grub_disk_read (&raw,
 169                                       (p.start
 170                                        + GRUB_PC_PARTITION_BSD_LABEL_SECTOR),
 171                                       0,
 172                                       sizeof (label),
 173                                       (char *) &label))
 174                     goto finish;
 175
 176                   /* Check if it is valid.  */
 177                   if (label.magic
 178                       != grub_cpu_to_le32 (GRUB_PC_PARTITION_BSD_LABEL_MAGIC))
 179                     {
 180                       grub_dprintf ("partition",
 181                                     "invalid disk label magic 0x%x on partition %d\n",
 182                                     label.magic, p.index);
 183                       continue;
 184                     }
 185                   for (pcdata.bsd_part = 0;
 186                        pcdata.bsd_part < grub_cpu_to_le16 (label.num_partitions);
 187                        pcdata.bsd_part++)
 188                     {
 189                       struct grub_pc_partition_bsd_entry *be
 190                         = label.entries + pcdata.bsd_part;
 191
 192                       p.start = grub_le_to_cpu32 (be->offset);
 193                       p.len = grub_le_to_cpu32 (be->size);
 194                       pcdata.bsd_type = be->fs_type;
 195
 196                       if (be->fs_type != GRUB_PC_PARTITION_BSD_TYPE_UNUSED)
 197                         if (hook (disk, &p))
 198                           return 1;
 199                     }
 200                 }
 201             }
 202           else if (pcdata.dos_part < 4)
 203             /* If this partition is a logical one, shouldn't increase the
 204                partition number.  */
 205             pcdata.dos_part++;
 206         }
 207
 208       /* Find an extended partition.  */
 209       for (i = 0; i < 4; i++)
 210         {
 211           e = mbr.entries + i;
 212
 213           if (grub_pc_partition_is_extended (e->type))
 214             {
 215               p.offset = pcdata.ext_offset + grub_le_to_cpu32 (e->start);
 216               if (! pcdata.ext_offset)
 217                 pcdata.ext_offset = p.offset;
 218
 219               break;
 220             }
 221         }
 222
 223       /* If no extended partition, the end.  */
 224       if (i == 4)
 225         break;
 226     }
 227
 228  finish:
 229   return grub_errno;
 230 }
 231
 232
 233 static grub_partition_t
 234 pc_partition_map_probe (grub_disk_t disk, const char *str)
 235 {
 236   grub_partition_t p;
 237   struct grub_pc_partition *pcdata;
 238
 239   auto int find_func (grub_disk_t d, const grub_partition_t partition);
 240
 241   int find_func (grub_disk_t d __attribute__ ((unused)),
 242                  const grub_partition_t partition)
 243     {
 244       struct grub_pc_partition *partdata = partition->data;
 245
 246       if ((pcdata->dos_part == partdata->dos_part || pcdata->dos_part == -1)
 247           && pcdata->bsd_part == partdata->bsd_part)
 248         {
 249           grub_memcpy (p, partition, sizeof (*p));
 250           p->data = pcdata;
 251           grub_memcpy (pcdata, partdata, sizeof (*pcdata));
 252           return 1;
 253         }
 254
 255       return 0;
 256     }
 257
 258   p = grub_partition_parse (str);
 259   if (! p)
 260     return 0;
 261
 262   pcdata = p->data;
 263   pc_partition_map_iterate (disk, find_func);
 264   if (grub_errno)
 265     goto fail;
 266
 267   if (p->index < 0)
 268     {
 269       grub_error (GRUB_ERR_BAD_DEVICE, "no such partition");
 270       goto fail;
 271     }
 272
 273   return p;
 274
 275  fail:
 276   grub_free (p);
 277   grub_free (pcdata);
 278   return 0;
 279 }
 280
 281
 282 static char *
 283 pc_partition_map_get_name (const grub_partition_t p)
 284 {
 285   char *name;
 286   struct grub_pc_partition *pcdata = p->data;
 287
 288   name = grub_malloc (13);
 289   if (! name)
 290     return 0;
 291
 292   if (pcdata->bsd_part < 0)
 293     grub_sprintf (name, "%d", pcdata->dos_part + 1);
 294   else if (pcdata->dos_part < 0)
 295     grub_sprintf (name, "%c", pcdata->bsd_part + 'a');
 296   else
 297     grub_sprintf (name, "%d,%c", pcdata->dos_part + 1, pcdata->bsd_part + 'a');
 298
 299   return name;
 300 }
 301
 302 \f
 303 /* Partition map type.  */
 304 static struct grub_partition_map grub_pc_partition_map =
 305   {
 306     .name = "pc_partition_map",
 307     .iterate = pc_partition_map_iterate,
 308     .probe = pc_partition_map_probe,
 309     .get_name = pc_partition_map_get_name
 310   };
 311
 312 GRUB_MOD_INIT(pc_partition_map)
 313 {
 314   grub_partition_map_register (&grub_pc_partition_map);
 315 #ifndef GRUB_UTIL
 316   my_mod = mod;
 317 #endif
 318 }
 319
 320 GRUB_MOD_FINI(pc_partition_map)
 321 {
 322   grub_partition_map_unregister (&grub_pc_partition_map);
 323 }