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  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, p.start, p.len);
 142
 143           /* If this is a GPT partition, this MBR is just a dummy.  */
 144           if (e->type == GRUB_PC_PARTITION_TYPE_GPT_DISK && p.index == 0)
 145             return grub_error (GRUB_ERR_BAD_PART_TABLE, "dummy mbr");
 146
 147           /* If this partition is a normal one, call the hook.  */
 148           if (! grub_pc_partition_is_empty (e->type)
 149               && ! grub_pc_partition_is_extended (e->type))
 150             {
 151               pcdata.dos_part++;
 152
 153               if (hook (disk, &p))
 154                 goto finish;
 155
 156               /* Check if this is a BSD partition.  */
 157               if (grub_pc_partition_is_bsd (e->type))
 158                 {
 159                   /* Check if the BSD label is within the DOS partition.  */
 160                   if (p.len <= GRUB_PC_PARTITION_BSD_LABEL_SECTOR)
 161                     return grub_error (GRUB_ERR_BAD_PART_TABLE,
 162                                        "no space for disk label");
 163
 164                   /* Read the BSD label.  */
 165                   if (grub_disk_read (&raw,
 166                                       (p.start
 167                                        + GRUB_PC_PARTITION_BSD_LABEL_SECTOR),
 168                                       0,
 169                                       sizeof (label),
 170                                       (char *) &label))
 171                     goto finish;
 172
 173                   /* Check if it is valid.  */
 174                   if (label.magic
 175                       != grub_cpu_to_le32 (GRUB_PC_PARTITION_BSD_LABEL_MAGIC))
 176                     return grub_error (GRUB_ERR_BAD_PART_TABLE,
 177                                        "invalid disk label magic 0x%x",
 178                                        label.magic);
 179
 180                   for (pcdata.bsd_part = 0;
 181                        pcdata.bsd_part < grub_cpu_to_le16 (label.num_partitions);
 182                        pcdata.bsd_part++)
 183                     {
 184                       struct grub_pc_partition_bsd_entry *be
 185                         = label.entries + pcdata.bsd_part;
 186
 187                       p.start = grub_le_to_cpu32 (be->offset);
 188                       p.len = grub_le_to_cpu32 (be->size);
 189                       pcdata.bsd_type = be->fs_type;
 190
 191                       if (be->fs_type != GRUB_PC_PARTITION_BSD_TYPE_UNUSED)
 192                         if (hook (disk, &p))
 193                           goto finish;
 194                     }
 195                 }
 196             }
 197           else if (pcdata.dos_part < 4)
 198             /* If this partition is a logical one, shouldn't increase the
 199                partition number.  */
 200             pcdata.dos_part++;
 201         }
 202
 203       /* Find an extended partition.  */
 204       for (i = 0; i < 4; i++)
 205         {
 206           e = mbr.entries + i;
 207
 208           if (grub_pc_partition_is_extended (e->type))
 209             {
 210               p.offset = pcdata.ext_offset + grub_le_to_cpu32 (e->start);
 211               if (! pcdata.ext_offset)
 212                 pcdata.ext_offset = p.offset;
 213
 214               break;
 215             }
 216         }
 217
 218       /* If no extended partition, the end.  */
 219       if (i == 4)
 220         break;
 221     }
 222
 223  finish:
 224   return grub_errno;
 225 }
 226
 227
 228 static grub_partition_t
 229 pc_partition_map_probe (grub_disk_t disk, const char *str)
 230 {
 231   grub_partition_t p;
 232   struct grub_pc_partition *pcdata;
 233
 234   auto int find_func (grub_disk_t d, const grub_partition_t partition);
 235
 236   int find_func (grub_disk_t d __attribute__ ((unused)),
 237                  const grub_partition_t partition)
 238     {
 239       struct grub_pc_partition *partdata = partition->data;
 240
 241       if ((pcdata->dos_part == partdata->dos_part || pcdata->dos_part == -1)
 242           && pcdata->bsd_part == partdata->bsd_part)
 243         {
 244           grub_memcpy (p, partition, sizeof (*p));
 245           p->data = pcdata;
 246           grub_memcpy (pcdata, partdata, sizeof (*pcdata));
 247           return 1;
 248         }
 249
 250       return 0;
 251     }
 252
 253   p = grub_partition_parse (str);
 254   if (! p)
 255     return 0;
 256
 257   pcdata = p->data;
 258   if (pc_partition_map_iterate (disk, find_func))
 259     goto fail;
 260
 261   if (p->index < 0)
 262     {
 263       grub_error (GRUB_ERR_BAD_DEVICE, "no such partition");
 264       goto fail;
 265     }
 266
 267   return p;
 268
 269  fail:
 270   grub_free (p);
 271   grub_free (pcdata);
 272   return 0;
 273 }
 274
 275
 276 static char *
 277 pc_partition_map_get_name (const grub_partition_t p)
 278 {
 279   char *name;
 280   struct grub_pc_partition *pcdata = p->data;
 281
 282   name = grub_malloc (13);
 283   if (! name)
 284     return 0;
 285
 286   if (pcdata->bsd_part < 0)
 287     grub_sprintf (name, "%d", pcdata->dos_part + 1);
 288   else if (pcdata->dos_part < 0)
 289     grub_sprintf (name, "%c", pcdata->bsd_part + 'a');
 290   else
 291     grub_sprintf (name, "%d,%c", pcdata->dos_part + 1, pcdata->bsd_part + 'a');
 292
 293   return name;
 294 }
 295
 296 \f
 297 /* Partition map type.  */
 298 static struct grub_partition_map grub_pc_partition_map =
 299   {
 300     .name = "pc_partition_map",
 301     .iterate = pc_partition_map_iterate,
 302     .probe = pc_partition_map_probe,
 303     .get_name = pc_partition_map_get_name
 304   };
 305
 306 GRUB_MOD_INIT(pc_partition_map)
 307 {
 308   grub_partition_map_register (&grub_pc_partition_map);
 309 #ifndef GRUB_UTIL
 310   my_mod = mod;
 311 #endif
 312 }
 313
 314 GRUB_MOD_FINI(pc_partition_map)
 315 {
 316   grub_partition_map_unregister (&grub_pc_partition_map);
 317 }