Fix possible runtime panic in Lgetxattr
If `unix.Lgetxattr` returns an error, then `sz == -1` which will cause a
runtime panic if `errno == unix.ERANGE`.
@@ -6,19 +6,28 @@ import "golang.org/x/sys/unix"
// and associated with the given path in the file system.
// It will returns a nil slice and nil error if the xattr is not set.
func Lgetxattr(path string, attr string) ([]byte, error) {
+ // Start with a 128 length byte array
dest := make([]byte, 128)
sz, errno := unix.Lgetxattr(path, attr, dest)
- if errno == unix.ENODATA {
+
+ switch {
+ case errno == unix.ENODATA:
return nil, nil
+ case errno == unix.ERANGE:
+ // 128 byte array might just not be good enough. A dummy buffer is used
+ // to get the real size of the xattrs on disk
+ sz, errno = unix.Lgetxattr(path, attr, []byte{})
+ if errno != nil {
+ return nil, errno
}
- if errno == unix.ERANGE {
dest = make([]byte, sz)
sz, errno = unix.Lgetxattr(path, attr, dest)
- }
if errno != nil {
return nil, errno
}
-
+ case errno != nil:
+ return nil, errno
+ }
return dest[:sz], nil
}
