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-rw-r--r--libblkid/src/superblocks/exfat.c157
1 files changed, 157 insertions, 0 deletions
diff --git a/libblkid/src/superblocks/exfat.c b/libblkid/src/superblocks/exfat.c
new file mode 100644
index 0000000..f586ec7
--- /dev/null
+++ b/libblkid/src/superblocks/exfat.c
@@ -0,0 +1,157 @@
+/*
+ * 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 vermin;
+ uint8_t vermaj;
+ } 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[22];
+ uint8_t reserved[8];
+} __attribute__((__packed__));
+
+#define BLOCK_SIZE(sb) (1u << (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 uint64_t block_to_offset(const struct exfat_super_block *sb,
+ uint64_t block)
+{
+ return block << sb->block_bits;
+}
+
+static uint64_t cluster_to_block(const struct exfat_super_block *sb,
+ uint32_t cluster)
+{
+ return le32_to_cpu(sb->cluster_block_start) +
+ ((uint64_t) (cluster - EXFAT_FIRST_DATA_CLUSTER)
+ << sb->bpc_bits);
+}
+
+static uint64_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;
+ uint64_t fat_offset;
+
+ fat_offset = block_to_offset(sb, le32_to_cpu(sb->fat_block_start))
+ + (uint64_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);
+ uint64_t offset = cluster_to_offset(sb, cluster);
+ uint8_t *entry;
+ const size_t max_iter = 10000;
+ size_t i = 0;
+
+ for (; i < max_iter; i++) {
+ 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);
+ }
+ }
+
+ return NULL;
+}
+
+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 || !CLUSTER_SIZE(sb))
+ return errno ? -errno : BLKID_PROBE_NONE;
+
+ label = find_label(pr, sb);
+ if (label)
+ blkid_probe_set_utf8label(pr, label->name,
+ min((size_t) label->length * 2, sizeof(label->name)),
+ UL_ENCODE_UTF16LE);
+ else if (errno)
+ return -errno;
+
+ 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, "%u.%u",
+ sb->version.vermaj, sb->version.vermin);
+
+ blkid_probe_set_block_size(pr, BLOCK_SIZE(sb));
+
+ return BLKID_PROBE_OK;
+}
+
+const struct blkid_idinfo exfat_idinfo =
+{
+ .name = "exfat",
+ .usage = BLKID_USAGE_FILESYSTEM,
+ .probefunc = probe_exfat,
+ .magics =
+ {
+ { .magic = "EXFAT ", .len = 8, .sboff = 3 },
+ { NULL }
+ }
+};