From 59e890ef7bf5b80d96802e115255f969491ef645 Mon Sep 17 00:00:00 2001 From: Christian Gmeiner Date: Wed, 12 Nov 2014 14:35:04 +0100 Subject: fs: make it possible to read the filesystem UUID Some filesystems have a UUID stored in its superblock. To allow using root=UUID=... for the kernel command line we need a way to read-out the filesystem UUID. changes rfc -> v1: - make the environment variable an option parameter. If not given, the UUID is printed out. If given, it is stored in the env variable. - corrected typos - return error codes changes v1 -> v2: - fix return code of do_fs_uuid(..) - document do_fs_uuid(..) - implement fs_uuid_unsuported(..) be more consistent with the way other optional functionality works changes v2 -> v3: - change ext4fs_uuid(..) to make use of #if .. #else .. #endif construct to get rid of unreachable code Hit any key to stop autoboot: 0 => fsuuid fsuuid - Look up a filesystem UUID Usage: fsuuid : - print filesystem UUID fsuuid : - set environment variable to filesystem UUID => fsuuid mmc 0:1 d9f9fc05-45ae-4a36-a616-fccce0e4f887 => fsuuid mmc 0:2 eb3db83c-7b28-499f-95ce-9e0bb21cda81 => fsuuid mmc 0:1 uuid1 => fsuuid mmc 0:2 uuid2 => printenv uuid1 uuid1=d9f9fc05-45ae-4a36-a616-fccce0e4f887 => printenv uuid2 uuid2=eb3db83c-7b28-499f-95ce-9e0bb21cda81 => Signed-off-by: Christian Gmeiner Acked-by: Stephen Warren --- fs/ext4/ext4fs.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) (limited to 'fs/ext4') diff --git a/fs/ext4/ext4fs.c b/fs/ext4/ext4fs.c index cbdc22026d..87d5128518 100644 --- a/fs/ext4/ext4fs.c +++ b/fs/ext4/ext4fs.c @@ -231,3 +231,18 @@ int ext4_read_file(const char *filename, void *buf, int offset, int len) return len_read; } + +int ext4fs_uuid(char *uuid_str) +{ + if (ext4fs_root == NULL) + return -1; + +#ifdef CONFIG_LIB_UUID + uuid_bin_to_str((unsigned char *)ext4fs_root->sblock.unique_id, + uuid_str, UUID_STR_FORMAT_STD); + + return 0; +#else + return -ENOSYS; +#endif +} -- cgit v1.2.1