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>
diff --git a/fs/fs.c b/fs/fs.c
index dd680f3..e4ad6bc 100644
--- a/fs/fs.c
+++ b/fs/fs.c
@@ -15,6 +15,7 @@
*/
#include <config.h>
+#include <errno.h>
#include <common.h>
#include <part.h>
#include <ext4fs.h>
@@ -67,6 +68,11 @@
{
}
+static inline int fs_uuid_unsupported(char *uuid_str)
+{
+ return -1;
+}
+
struct fstype_info {
int fstype;
/*
@@ -86,6 +92,7 @@
int (*read)(const char *filename, void *buf, int offset, int len);
int (*write)(const char *filename, void *buf, int offset, int len);
void (*close)(void);
+ int (*uuid)(char *uuid_str);
};
static struct fstype_info fstypes[] = {
@@ -100,6 +107,7 @@
.size = fat_size,
.read = fat_read_file,
.write = fs_write_unsupported,
+ .uuid = fs_uuid_unsupported,
},
#endif
#ifdef CONFIG_FS_EXT4
@@ -113,6 +121,7 @@
.size = ext4fs_size,
.read = ext4_read_file,
.write = fs_write_unsupported,
+ .uuid = ext4fs_uuid,
},
#endif
#ifdef CONFIG_SANDBOX
@@ -126,6 +135,7 @@
.size = sandbox_fs_size,
.read = fs_read_sandbox,
.write = fs_write_sandbox,
+ .uuid = fs_uuid_unsupported,
},
#endif
{
@@ -138,6 +148,7 @@
.size = fs_size_unsupported,
.read = fs_read_unsupported,
.write = fs_write_unsupported,
+ .uuid = fs_uuid_unsupported,
},
};
@@ -206,6 +217,13 @@
fs_type = FS_TYPE_ANY;
}
+int fs_uuid(char *uuid_str)
+{
+ struct fstype_info *info = fs_get_info(fs_type);
+
+ return info->uuid(uuid_str);
+}
+
int fs_ls(const char *dirname)
{
int ret;
@@ -443,3 +461,28 @@
return 0;
}
+
+int do_fs_uuid(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[],
+ int fstype)
+{
+ int ret;
+ char uuid[37];
+ memset(uuid, 0, sizeof(uuid));
+
+ if (argc < 3 || argc > 4)
+ return CMD_RET_USAGE;
+
+ if (fs_set_blk_dev(argv[1], argv[2], fstype))
+ return 1;
+
+ ret = fs_uuid(uuid);
+ if (ret)
+ return CMD_RET_FAILURE;
+
+ if (argc == 4)
+ setenv(argv[3], uuid);
+ else
+ printf("%s\n", uuid);
+
+ return CMD_RET_SUCCESS;
+}