partmap/sunpc.c

   1 /* sunpc.c - Read SUN PC style partition tables.  */
   2 /*
   3  *  GRUB  --  GRand Unified Bootloader
   4  *  Copyright (C) 2002,2005,2006,2007,2009  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/disk.h>
  22 #include <grub/mm.h>
  23 #include <grub/misc.h>
  24 #include <grub/dl.h>
  25 #include <grub/symbol.h>
  26 #include <grub/types.h>
  27 #include <grub/err.h>
  28
  29 #define GRUB_PARTMAP_SUN_PC_MAGIC 0xDABE
  30 #define GRUB_PARTMAP_SUN_PC_MAX_PARTS 16
  31 #define GRUB_PARTMAP_SUN_PC_WHOLE_DISK_ID 0x05
  32
  33 struct grub_sun_pc_partition_descriptor
  34 {
  35   grub_uint16_t id;
  36   grub_uint16_t unused;
  37   grub_uint32_t start_sector;
  38   grub_uint32_t num_sectors;
  39 } __attribute__ ((packed));
  40
  41 struct grub_sun_pc_block
  42 {
  43   grub_uint8_t unused[72];
  44   struct grub_sun_pc_partition_descriptor partitions[GRUB_PARTMAP_SUN_PC_MAX_PARTS];
  45   grub_uint8_t unused2[244];
  46   grub_uint16_t  magic;         /* Magic number.  */
  47   grub_uint16_t  csum;          /* Label xor'd checksum.  */
  48 } __attribute__ ((packed));
  49
  50 static struct grub_partition_map grub_sun_pc_partition_map;
  51
  52 /* Verify checksum (true=ok).  */
  53 static int
  54 grub_sun_is_valid (struct grub_sun_pc_block *label)
  55 {
  56   grub_uint16_t *pos;
  57   grub_uint16_t sum = 0;
  58
  59   for (pos = (grub_uint16_t *) label;
  60        pos < (grub_uint16_t *) (label + 1);
  61        pos++)
  62     sum ^= *pos;
  63
  64   return ! sum;
  65 }
  66
  67 static grub_err_t
  68 sun_pc_partition_map_iterate (grub_disk_t disk,
  69                               int (*hook) (grub_disk_t disk,
  70                                            const grub_partition_t partition))
  71 {
  72   grub_partition_t p;
  73   struct grub_sun_pc_block block;
  74   int partnum;
  75   grub_err_t err;
  76
  77   p = (grub_partition_t) grub_zalloc (sizeof (struct grub_partition));
  78   if (! p)
  79     return grub_errno;
  80
  81   p->partmap = &grub_sun_pc_partition_map;
  82   err = grub_disk_read (disk, 1, 0, sizeof (struct grub_sun_pc_block), &block);
  83   if (err)
  84     {
  85       grub_free (p);
  86       return err;
  87     }
  88
  89   if (GRUB_PARTMAP_SUN_PC_MAGIC != grub_le_to_cpu16 (block.magic))
  90     {
  91       grub_free (p);
  92       return grub_error (GRUB_ERR_BAD_PART_TABLE,
  93                          "not a sun_pc partition table");
  94     }
  95
  96   if (! grub_sun_is_valid (&block))
  97     {
  98       grub_free (p);
  99       return grub_error (GRUB_ERR_BAD_PART_TABLE, "invalid checksum");
 100     }
 101
 102   /* Maybe another error value would be better, because partition
 103      table _is_ recognized but invalid.  */
 104   for (partnum = 0; partnum < GRUB_PARTMAP_SUN_PC_MAX_PARTS; partnum++)
 105     {
 106       struct grub_sun_pc_partition_descriptor *desc;
 107
 108       if (block.partitions[partnum].id == 0
 109           || block.partitions[partnum].id == GRUB_PARTMAP_SUN_PC_WHOLE_DISK_ID)
 110         continue;
 111
 112       desc = &block.partitions[partnum];
 113       p->start = grub_le_to_cpu32 (desc->start_sector);
 114       p->len = grub_le_to_cpu32 (desc->num_sectors);
 115       p->number = partnum;
 116       if (p->len)
 117         {
 118           if (hook (disk, p))
 119             partnum = GRUB_PARTMAP_SUN_PC_MAX_PARTS;
 120         }
 121     }
 122
 123   grub_free (p);
 124
 125   return grub_errno;
 126 }
 127
 128 /* Partition map type.  */
 129 static struct grub_partition_map grub_sun_pc_partition_map =
 130   {
 131     .name = "sunpc",
 132     .iterate = sun_pc_partition_map_iterate,
 133   };
 134
 135 GRUB_MOD_INIT(part_sunpc)
 136 {
 137   grub_partition_map_register (&grub_sun_pc_partition_map);
 138 }
 139
 140 GRUB_MOD_FINI(part_sunpc)
 141 {
 142   grub_partition_map_unregister (&grub_sun_pc_partition_map);
 143 }
 144