package system // import "github.com/docker/docker/pkg/system" import ( "golang.org/x/sys/unix" ) // Lgetxattr retrieves the value of the extended attribute identified by attr // 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) { sysErr := func(err error) ([]byte, error) { return nil, &XattrError{Op: "lgetxattr", Attr: attr, Path: path, Err: err} } // Start with a 128 length byte array dest := make([]byte, 128) sz, errno := unix.Lgetxattr(path, attr, dest) for errno == unix.ERANGE { // Buffer too small, use zero-sized buffer to get the actual size sz, errno = unix.Lgetxattr(path, attr, []byte{}) if errno != nil { return sysErr(errno) } dest = make([]byte, sz) sz, errno = unix.Lgetxattr(path, attr, dest) } switch { case errno == unix.ENODATA: return nil, nil case errno != nil: return sysErr(errno) } return dest[:sz], nil } // Lsetxattr sets the value of the extended attribute identified by attr // and associated with the given path in the file system. func Lsetxattr(path string, attr string, data []byte, flags int) error { err := unix.Lsetxattr(path, attr, data, flags) if err != nil { return &XattrError{Op: "lsetxattr", Attr: attr, Path: path, Err: err} } return nil }