rc: add config/unlock to unlock the config file

fs/config/rc.go

@@ -9,6 +9,37 @@ import (
 	"github.com/rclone/rclone/fs/rc"
 )
 
+func init() {
+	rc.Add(rc.Call{
+		Path:         "config/unlock",
+		Fn:           rcConfigPassword,
+		Title:        "Unlock the config file.",
+		AuthRequired: true,
+		Help: `
+Unlocks the config file if it is locked.
+
+Parameters:
+
+- 'config_password' - password to unlock the config file
+
+A good idea is to disable AskPassword before making this call
+`,
+	})
+}
+
+// Unlock the config file
+// A good idea is to disable AskPassword before making this call
+func rcConfigPassword(ctx context.Context, in rc.Params) (out rc.Params, err error) {
+	configPass, err := in.GetString("config_password")
+	if err != nil {
+		return nil, err
+	}
+	if SetConfigPassword(configPass) != nil {
+		return nil, errors.New("failed to set config password")
+	}
+	return nil, nil
+}
+
 func init() {
 	rc.Add(rc.Call{
 		Path:         "config/dump",

fs/config/rc_test.go

@@ -188,3 +188,17 @@ func TestRcPaths(t *testing.T) {
 	assert.Equal(t, config.GetCacheDir(), out["cache"])
 	assert.Equal(t, os.TempDir(), out["temp"])
 }
+
+func TestRcConfigUnlock(t *testing.T) {
+	call := rc.Calls.Get("config/unlock")
+	assert.NotNil(t, call)
+	in := rc.Params{
+		"config_password": "test",
+	}
+	out, err := call.Fn(context.Background(), in)
+	require.NoError(t, err)
+
+	assert.Nil(t, err)
+	assert.Nil(t, out)
+
+}