grub/partmap/acorn.c

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C
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/* acorn.c - Read Linux/ADFS partition tables. */
/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2005,2007 Free Software Foundation, Inc.
*
* GRUB is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* GRUB is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
*/
#include <grub/disk.h>
#include <grub/misc.h>
#include <grub/mm.h>
#include <grub/partition.h>
#include <grub/acorn_filecore.h>
#define LINUX_NATIVE_MAGIC grub_cpu_to_le32 (0xdeafa1de)
#define LINUX_SWAP_MAGIC grub_cpu_to_le32 (0xdeafab1e)
#define LINUX_MAP_ENTRIES (512 / 12)
#define NONADFS_PARTITION_TYPE_LINUX 9
#define NONADFS_PARTITION_TYPE_MASK 15
struct grub_acorn_boot_block
{
grub_uint8_t misc[0x1C0];
struct grub_filecore_disc_record disc_record;
grub_uint8_t flags;
grub_uint16_t start_cylinder;
grub_uint8_t checksum;
} __attribute__ ((packed, aligned));
struct linux_part
{
grub_uint32_t magic;
grub_uint32_t start;
grub_uint32_t size;
};
static struct grub_partition_map grub_acorn_partition_map;
static grub_err_t
acorn_partition_map_find (grub_disk_t disk, struct linux_part *m,
grub_disk_addr_t *sector)
{
struct grub_acorn_boot_block boot;
grub_err_t err;
unsigned int checksum = 0;
unsigned int heads;
unsigned int sectors_per_cylinder;
int i;
err = grub_disk_read (disk, 0xC00 / GRUB_DISK_SECTOR_SIZE, 0,
sizeof (struct grub_acorn_boot_block),
(char *) &boot);
if (err)
return err;
if ((boot.flags & NONADFS_PARTITION_TYPE_MASK) != NONADFS_PARTITION_TYPE_LINUX)
goto fail;
for (i = 0; i != 0x1ff; ++i)
checksum = (checksum & 0xff) + (checksum >> 8) + boot.misc[i];
if ((grub_uint8_t) checksum != boot.checksum)
goto fail;
heads = (boot.disc_record.heads
+ ((boot.disc_record.lowsector >> 6) & 1));
sectors_per_cylinder = boot.disc_record.secspertrack * heads;
*sector = grub_le_to_cpu16 (boot.start_cylinder) * sectors_per_cylinder;
return grub_disk_read (disk, *sector, 0,
sizeof (struct linux_part) * LINUX_MAP_ENTRIES,
(char *) m);
fail:
return grub_error (GRUB_ERR_BAD_PART_TABLE,
"Linux/ADFS partition map not found.");
}
static grub_err_t
acorn_partition_map_iterate (grub_disk_t disk,
int (*hook) (grub_disk_t disk,
const grub_partition_t partition))
{
struct grub_partition part;
struct grub_disk raw;
struct linux_part map[LINUX_MAP_ENTRIES];
int i;
grub_disk_addr_t sector;
grub_err_t err;
/* Enforce raw disk access. */
raw = *disk;
raw.partition = 0;
err = acorn_partition_map_find (&raw, map, &sector);
if (err)
return err;
part.partmap = &grub_acorn_partition_map;
for (i = 0; i != LINUX_MAP_ENTRIES; ++i)
{
if (map[i].magic != LINUX_NATIVE_MAGIC
&& map[i].magic != LINUX_SWAP_MAGIC)
return GRUB_ERR_NONE;
part.start = sector + map[i].start;
part.len = map[i].size;
part.offset = 6;
part.index = i;
if (hook (disk, &part))
return grub_errno;
}
return GRUB_ERR_NONE;
}
static grub_partition_t
acorn_partition_map_probe (grub_disk_t disk, const char *str)
{
struct linux_part map[LINUX_MAP_ENTRIES];
struct grub_disk raw = *disk;
unsigned long partnum = grub_strtoul (str, 0, 10) - 1;
grub_disk_addr_t sector;
grub_err_t err;
grub_partition_t p;
/* Enforce raw disk access. */
raw.partition = 0;
/* Get the partition number. */
if (partnum > LINUX_MAP_ENTRIES)
goto fail;
err = acorn_partition_map_find (&raw, map, &sector);
if (err)
return 0;
if (map[partnum].magic != LINUX_NATIVE_MAGIC
&& map[partnum].magic != LINUX_SWAP_MAGIC)
goto fail;
p = grub_malloc (sizeof (struct grub_partition));
if (! p)
return 0;
p->start = sector + map[partnum].start;
p->len = map[partnum].size;
p->offset = 6;
p->index = partnum;
return p;
fail:
grub_error (GRUB_ERR_BAD_FILENAME, "invalid partition");
return 0;
}
static char *
acorn_partition_map_get_name (const grub_partition_t p)
{
char *name;
name = grub_malloc (13);
if (! name)
return 0;
grub_sprintf (name, "%d", p->index + 1);
return name;
}
/* Partition map type. */
static struct grub_partition_map grub_acorn_partition_map =
{
.name = "Linux/ADFS partition map",
.iterate = acorn_partition_map_iterate,
.probe = acorn_partition_map_probe,
.get_name = acorn_partition_map_get_name
};
GRUB_MOD_INIT(acorn_partition_map)
{
grub_partition_map_register (&grub_acorn_partition_map);
}
GRUB_MOD_FINI(acorn_partition_map)
{
grub_partition_map_unregister (&grub_acorn_partition_map);
}