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authorChristian Gmeiner <christian.gmeiner@gmail.com>2014-11-12 14:35:04 +0100
committerTom Rini <trini@ti.com>2014-11-23 06:49:01 -0500
commit59e890ef7bf5b80d96802e115255f969491ef645 (patch)
tree570d6ef6e5a64a25e3a71eaf67273f8e0b8aa013 /fs/ext4/ext4fs.c
parent1b51d32c0f0ac7cdcab0ae04d531129a020cc903 (diff)
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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 <interface> <dev>:<part> - print filesystem UUID fsuuid <interface> <dev>:<part> <varname> - 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 <christian.gmeiner@gmail.com> Acked-by: Stephen Warren <swarren@nvidia.com>
Diffstat (limited to 'fs/ext4/ext4fs.c')
-rw-r--r--fs/ext4/ext4fs.c15
1 files changed, 15 insertions, 0 deletions
diff --git a/fs/ext4/ext4fs.c b/fs/ext4/ext4fs.c
index cbdc220..87d5128 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
+}