libblkid: add exFAT file system detection support

Add exFAT file system <http://en.wikipedia.org/wiki/ExFAT> detection support.

Signed-off-by: Andrew Nayenko <resver@gmail.com>
This commit is contained in:
Andrew Nayenko 2010-05-28 23:22:00 +04:00 committed by Karel Zak
parent 89074c1659
commit 8604c25570
6 changed files with 158 additions and 2 deletions

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@ -46,4 +46,5 @@ libblkid_superblocks_la_SOURCES = \
bfs.c \
drbd.c \
vmfs.c \
befs.c
befs.c \
exfat.c

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@ -0,0 +1,146 @@
/*
* Copyright (C) 2010 Andrew Nayenko <resver@gmail.com>
*
* This file may be redistributed under the terms of the
* GNU Lesser General Public License.
*/
#include "superblocks.h"
struct exfat_super_block {
uint8_t jump[3];
uint8_t oem_name[8];
uint8_t __unused1[53];
uint64_t block_start;
uint64_t block_count;
uint32_t fat_block_start;
uint32_t fat_block_count;
uint32_t cluster_block_start;
uint32_t cluster_count;
uint32_t rootdir_cluster;
uint8_t volume_serial[4];
struct {
uint8_t minor;
uint8_t major;
} version;
uint16_t volume_state;
uint8_t block_bits;
uint8_t bpc_bits;
uint8_t fat_count;
uint8_t drive_no;
uint8_t allocated_percent;
} __attribute__((__packed__));
struct exfat_entry_label {
uint8_t type;
uint8_t length;
uint8_t name[30];
} __attribute__((__packed__));
#define BLOCK_SIZE(sb) (1 << (sb)->block_bits)
#define CLUSTER_SIZE(sb) (BLOCK_SIZE(sb) << (sb)->bpc_bits)
#define EXFAT_FIRST_DATA_CLUSTER 2
#define EXFAT_LAST_DATA_CLUSTER 0xffffff6
#define EXFAT_ENTRY_SIZE 32
#define EXFAT_ENTRY_EOD 0x00
#define EXFAT_ENTRY_LABEL 0x83
static blkid_loff_t block_to_offset(const struct exfat_super_block *sb,
blkid_loff_t block)
{
return (blkid_loff_t) block << sb->block_bits;
}
static blkid_loff_t cluster_to_block(const struct exfat_super_block *sb,
uint32_t cluster)
{
return le32_to_cpu(sb->cluster_block_start) +
((blkid_loff_t) (cluster - EXFAT_FIRST_DATA_CLUSTER)
<< sb->bpc_bits);
}
static blkid_loff_t cluster_to_offset(const struct exfat_super_block *sb,
uint32_t cluster)
{
return block_to_offset(sb, cluster_to_block(sb, cluster));
}
static uint32_t next_cluster(blkid_probe pr,
const struct exfat_super_block *sb, uint32_t cluster)
{
uint32_t *next;
blkid_loff_t fat_offset;
fat_offset = block_to_offset(sb, le32_to_cpu(sb->fat_block_start))
+ (blkid_loff_t) cluster * sizeof(cluster);
next = (uint32_t *) blkid_probe_get_buffer(pr, fat_offset,
sizeof(uint32_t));
if (!next)
return 0;
return le32_to_cpu(*next);
}
static struct exfat_entry_label *find_label(blkid_probe pr,
const struct exfat_super_block *sb)
{
uint32_t cluster = le32_to_cpu(sb->rootdir_cluster);
blkid_loff_t offset = cluster_to_offset(sb, cluster);
uint8_t *entry;
for (;;) {
entry = (uint8_t *) blkid_probe_get_buffer(pr, offset,
EXFAT_ENTRY_SIZE);
if (!entry)
return NULL;
if (entry[0] == EXFAT_ENTRY_EOD)
return NULL;
if (entry[0] == EXFAT_ENTRY_LABEL)
return (struct exfat_entry_label *) entry;
offset += EXFAT_ENTRY_SIZE;
if (offset % CLUSTER_SIZE(sb) == 0) {
cluster = next_cluster(pr, sb, cluster);
if (cluster < EXFAT_FIRST_DATA_CLUSTER)
return NULL;
if (cluster > EXFAT_LAST_DATA_CLUSTER)
return NULL;
offset = cluster_to_offset(sb, cluster);
}
}
}
static int probe_exfat(blkid_probe pr, const struct blkid_idmag *mag)
{
struct exfat_super_block *sb;
struct exfat_entry_label *label;
sb = blkid_probe_get_sb(pr, mag, struct exfat_super_block);
if (!sb)
return -1;
label = find_label(pr, sb);
if (label)
blkid_probe_set_utf8label(pr, label->name,
min(label->length * 2, 30), BLKID_ENC_UTF16LE);
blkid_probe_sprintf_uuid(pr, sb->volume_serial, 4,
"%02hhX%02hhX-%02hhX%02hhX",
sb->volume_serial[3], sb->volume_serial[2],
sb->volume_serial[1], sb->volume_serial[0]);
blkid_probe_sprintf_version(pr, "%hu.%hu",
sb->version.major, sb->version.minor);
return 0;
}
const struct blkid_idinfo exfat_idinfo =
{
.name = "exfat",
.usage = BLKID_USAGE_FILESYSTEM,
.probefunc = probe_exfat,
.magics =
{
{ .magic = "EXFAT ", .len = 8, .sboff = 3 },
{ NULL }
}
};

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@ -139,7 +139,8 @@ static const struct blkid_idinfo *idinfos[] =
&ubifs_idinfo,
&bfs_idinfo,
&vmfs_fs_idinfo,
&befs_idinfo
&befs_idinfo,
&exfat_idinfo
};
/*

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@ -65,6 +65,7 @@ extern const struct blkid_idinfo vmfs_volume_idinfo;
extern const struct blkid_idinfo vmfs_fs_idinfo;
extern const struct blkid_idinfo drbd_idinfo;
extern const struct blkid_idinfo befs_idinfo;
extern const struct blkid_idinfo exfat_idinfo;
/*
* superblock functions

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@ -0,0 +1,7 @@
ID_FS_LABEL=Новый_том
ID_FS_LABEL_ENC=Новый\x20том
ID_FS_TYPE=exfat
ID_FS_USAGE=filesystem
ID_FS_UUID=9C23-8877
ID_FS_UUID_ENC=9C23-8877
ID_FS_VERSION=1.0

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