interfaces/udev: add udev support code

This patch adds a function for reloading the udev database.

Signed-off-by: Zygmunt Krynicki <zygmunt.krynicki@canonical.com>

interfaces/udev/udev.go

@@ -0,0 +1,37 @@
+// -*- Mode: Go; indent-tabs-mode: t -*-
+
+/*
+ * Copyright (C) 2016 Canonical Ltd
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 3 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+package udev
+
+import (
+	"os/exec"
+)
+
+// ReloadRules runs two commands that reload udev rule database.
+//
+// The commands are: udevadm control --reload-rules
+//                   udevadm trigger
+func ReloadRules() error {
+	err := exec.Command("udevadm", "control", "--reload-rules").Run()
+	if err != nil {
+		return err
+	}
+	err = exec.Command("udevadm", "trigger").Run()
+	return err
+}

interfaces/udev/udev_test.go

@@ -0,0 +1,57 @@
+// -*- Mode: Go; indent-tabs-mode: t -*-
+
+/*
+ * Copyright (C) 2016 Canonical Ltd
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 3 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+package udev_test
+
+import (
+	"testing"
+
+	. "gopkg.in/check.v1"
+
+	"github.com/ubuntu-core/snappy/interfaces/udev"
+	"github.com/ubuntu-core/snappy/testutil"
+)
+
+func Test(t *testing.T) {
+	TestingT(t)
+}
+
+type uDevSuite struct {
+	testutil.ExecTest
+}
+
+var _ = Suite(&uDevSuite{})
+
+// Tests for ReloadRules()
+
+func (s *uDevSuite) TestReloadUDevRulesRunsUDevAdm(c *C) {
+	s.ExecTest.MockExecutable(c, "udevadm")
+	err := udev.ReloadRules()
+	c.Assert(err, IsNil)
+	c.Assert(s.CallsToExecutable(c, "udevadm"), DeepEquals, []string{
+		"control --reload-rules",
+		"trigger",
+	})
+}
+
+func (s *uDevSuite) TestReloadUDevRulesReportsErrors(c *C) {
+	s.ExecTest.MockFailingExecutable(c, "udevadm", 42)
+	err := udev.ReloadRules()
+	c.Assert(err, ErrorMatches, "exit status 42")
+}