fs/fat: implement fsuuid command

The FAT file system does not have a UUID but a 4 byte volume ID.
Let the fsuuid command show it in XXXX-XXXX format.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>

2 files changed, 19 insertions, 1 deletions

diff --git a/fs/fat/fat.c b/fs/fat/fat.c
index c9742d534b..157dad60a4 100644
--- a/fs/fat/fat.c
+++ b/fs/fat/fat.c
@@ -1377,3 +1377,21 @@ void fat_closedir(struct fs_dir_stream *dirs)
 void fat_close(void)
 {
 }
+
+int fat_uuid(char *uuid_str)
+{
+	boot_sector bs;
+	volume_info volinfo;
+	int fatsize;
+	int ret;
+	u8 *id;
+
+	ret = read_bootsectandvi(&bs, &volinfo, &fatsize);
+	if (ret)
+		return ret;
+
+	id = volinfo.volume_id;
+	sprintf(uuid_str, "%02X%02X-%02X%02X", id[3], id[2], id[1], id[0]);
+
+	return 0;
+}
diff --git a/fs/fs.c b/fs/fs.c
index 7a4020607a..5e80648b5b 100644
--- a/fs/fs.c
+++ b/fs/fs.c
@@ -194,7 +194,7 @@ static struct fstype_info fstypes[] = {
 		.unlink = fs_unlink_unsupported,
 		.mkdir = fs_mkdir_unsupported,
 #endif
-		.uuid = fs_uuid_unsupported,
+		.uuid = fat_uuid,
 		.opendir = fat_opendir,
 		.readdir = fat_readdir,
 		.closedir = fat_closedir,