volume_id: add exFAT detection
function old new delta
volume_id_probe_exfat - 294 +294
Signed-off-by: S-G Bergh <sgb@systemasis.org>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/util-linux/Config.src b/util-linux/Config.src
index 3355e97..e4516dd 100644
--- a/util-linux/Config.src
+++ b/util-linux/Config.src
@@ -734,6 +734,15 @@
help
TODO
+config FEATURE_VOLUMEID_EXFAT
+ bool "exFAT filesystem"
+ default y
+ depends on VOLUMEID
+ help
+ exFAT (extended FAT) is a proprietary file system designed especially
+ for flash drives. It has many features from NTFS, but with less
+ overhead. exFAT is used on most SDXC cards for consumer electronics.
+
config FEATURE_VOLUMEID_HFS
bool "hfs filesystem"
default y
diff --git a/util-linux/volume_id/Kbuild.src b/util-linux/volume_id/Kbuild.src
index 39a2d8c..759fdaa 100644
--- a/util-linux/volume_id/Kbuild.src
+++ b/util-linux/volume_id/Kbuild.src
@@ -33,6 +33,7 @@
### lib-$(CONFIG_FEATURE_VOLUMEID_MSDOS) += msdos.o
lib-$(CONFIG_FEATURE_VOLUMEID_NILFS) += nilfs.o
lib-$(CONFIG_FEATURE_VOLUMEID_NTFS) += ntfs.o
+lib-$(CONFIG_FEATURE_VOLUMEID_EXFAT) += exfat.o
lib-$(CONFIG_FEATURE_VOLUMEID_REISERFS) += reiserfs.o
lib-$(CONFIG_FEATURE_VOLUMEID_UDF) += udf.o
### lib-$(CONFIG_FEATURE_VOLUMEID_UFS) += ufs.o
diff --git a/util-linux/volume_id/exfat.c b/util-linux/volume_id/exfat.c
new file mode 100644
index 0000000..a38a891
--- /dev/null
+++ b/util-linux/volume_id/exfat.c
@@ -0,0 +1,130 @@
+/*
+ * volume_id - reads filesystem label and uuid
+ *
+ * Copyright (C) 2012 S-G Bergh <sgb@systemasis.org>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include "volume_id_internal.h"
+
+#define EXFAT_SB_OFFSET 0
+#define EXFAT_DIR_ENTRY_SZ 32
+#define EXFAT_MAX_DIR_ENTRIES 100
+
+struct exfat_super_block {
+/* 0x00 */ uint8_t boot_jump[3];
+/* 0x03 */ uint8_t fs_name[8];
+/* 0x0B */ uint8_t must_be_zero[53];
+/* 0x40 */ uint64_t partition_offset;
+/* 0x48 */ uint64_t volume_length;
+/* 0x50 */ uint32_t fat_offset; // Sector address of 1st FAT
+/* 0x54 */ uint32_t fat_size; // In sectors
+/* 0x58 */ uint32_t cluster_heap_offset; // Sector address of Data Region
+/* 0x5C */ uint32_t cluster_count;
+/* 0x60 */ uint32_t root_dir; // Cluster address of Root Directory
+/* 0x64 */ uint8_t vol_serial_nr[4]; // Volume ID
+/* 0x68 */ uint16_t fs_revision; // VV.MM
+/* 0x6A */ uint16_t vol_flags;
+/* 0x6C */ uint8_t bytes_per_sector; // Power of 2: 9 => 512, 12 => 4096
+/* 0x6D */ uint8_t sectors_per_cluster; // Power of 2
+/* 0x6E */ uint8_t nr_of_fats; // 2 for TexFAT
+/* 0x6F */ // ...
+} PACKED;
+
+struct exfat_dir_entry {
+/* 0x00 */ uint8_t entry_type;
+ union {
+ struct volume_label {
+/* 0x01 */ uint8_t char_count; // Length of label
+/* 0x02 */ uint16_t vol_label[11]; // UTF16 string without null termination
+/* 0x18 */ uint8_t reserved[8];
+/* 0x20 */ } PACKED label;
+ struct volume_guid {
+/* 0x01 */ uint8_t sec_count;
+/* 0x02 */ uint16_t set_checksum;
+/* 0x04 */ uint16_t flags;
+/* 0x06 */ uint8_t vol_guid[16];
+/* 0x16 */ uint8_t reserved[10];
+/* 0x20 */ } PACKED guid;
+ } PACKED type;
+} PACKED;
+
+int FAST_FUNC volume_id_probe_exfat(struct volume_id *id /*,uint64_t off*/)
+{
+ struct exfat_super_block *sb;
+ struct exfat_dir_entry *de;
+ unsigned sector_sz;
+ unsigned cluster_sz;
+ uint64_t root_dir_off;
+ unsigned count;
+ unsigned need_lbl_guid;
+
+ // Primary super block
+ dbg("exFAT: probing at offset 0x%x", EXFAT_SB_OFFSET);
+ sb = volume_id_get_buffer(id, EXFAT_SB_OFFSET, sizeof(*sb));
+
+ if (!sb)
+ return -1;
+
+ if (memcmp(sb->fs_name, "EXFAT ", 8) != 0)
+ return -1;
+
+ sector_sz = 1 << sb->bytes_per_sector;
+ cluster_sz = sector_sz << sb->sectors_per_cluster;
+ // There are no clusters 0 and 1, so the first cluster is 2.
+ root_dir_off = (uint64_t)EXFAT_SB_OFFSET +
+ // Hmm... should we cast sector_sz/cluster_sz to uint64_t?
+ (le32_to_cpu(sb->cluster_heap_offset)) * sector_sz +
+ (le32_to_cpu(sb->root_dir) - 2) * cluster_sz;
+ dbg("exFAT: sector size 0x%x bytes", sector_sz);
+ dbg("exFAT: cluster size 0x%x bytes", cluster_sz);
+ dbg("exFAT: root dir is at 0x%llx", (long long)root_dir_off);
+
+ // Use DOS uuid as fallback, if no GUID set
+ volume_id_set_uuid(id, sb->vol_serial_nr, UUID_DOS);
+
+ // EXFAT_MAX_DIR_ENTRIES is used as a safety belt.
+ // The Root Directory may hold an unlimited number of entries,
+ // so we do not want to check all. Usually label and GUID
+ // are in the beginning, but there are no guarantees.
+ need_lbl_guid = (1 << 0) | (1 << 1);
+ for (count = 0; count < EXFAT_MAX_DIR_ENTRIES; count++) {
+ de = volume_id_get_buffer(id, root_dir_off + (count * EXFAT_DIR_ENTRY_SZ), EXFAT_DIR_ENTRY_SZ);
+ if (de == NULL)
+ break;
+ if (de->entry_type == 0x00) {
+ // End of Directory Marker
+ dbg("exFAT: End of root directory reached after %u entries", count);
+ break;
+ }
+ if (de->entry_type == 0x83) {
+ // Volume Label Directory Entry
+ volume_id_set_label_unicode16(id, (uint8_t *)de->type.label.vol_label,
+ LE, 2 * de->type.label.char_count);
+ need_lbl_guid &= ~(1 << 0);
+ }
+ if (de->entry_type == 0xA0) {
+ // Volume GUID Directory Entry
+ volume_id_set_uuid(id, de->type.guid.vol_guid, UUID_DCE);
+ need_lbl_guid &= ~(1 << 1);
+ }
+ if (!need_lbl_guid)
+ break;
+ }
+
+ IF_FEATURE_BLKID_TYPE(id->type = "exfat";)
+ return 0;
+}
diff --git a/util-linux/volume_id/volume_id.c b/util-linux/volume_id/volume_id.c
index c1d6152..3c3c698 100644
--- a/util-linux/volume_id/volume_id.c
+++ b/util-linux/volume_id/volume_id.c
@@ -93,6 +93,9 @@
#if ENABLE_FEATURE_VOLUMEID_FAT
volume_id_probe_vfat,
#endif
+#if ENABLE_FEATURE_VOLUMEID_EXFAT
+ volume_id_probe_exfat,
+#endif
#if ENABLE_FEATURE_VOLUMEID_MAC
volume_id_probe_mac_partition_map,
#endif
diff --git a/util-linux/volume_id/volume_id_internal.h b/util-linux/volume_id/volume_id_internal.h
index 1c2e0ff..03dc46f 100644
--- a/util-linux/volume_id/volume_id_internal.h
+++ b/util-linux/volume_id/volume_id_internal.h
@@ -216,6 +216,8 @@
int FAST_FUNC volume_id_probe_ntfs(struct volume_id *id /*,uint64_t off*/);
+int FAST_FUNC volume_id_probe_exfat(struct volume_id *id /*,uint64_t off*/);
+
int FAST_FUNC volume_id_probe_ocfs2(struct volume_id *id /*,uint64_t off*/);
int FAST_FUNC volume_id_probe_reiserfs(struct volume_id *id /*,uint64_t off*/);