Hostname1 api

Add support for the systemd-hostnamed D-Bus interface.

See: https://www.freedesktop.org/software/systemd/man/latest/org.freedesktop.hostname1.html
Signed-off-by: Ananth Bhaskararaman <[email protected]>

hostname1/dbus.go

@@ -0,0 +1,302 @@
+// Copyright 2015 CoreOS, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package hostname1 provides integration with the systemd hostnamed API.
+// See https://www.freedesktop.org/software/systemd/man/latest/org.freedesktop.hostname1.html
+package hostname1
+
+import (
+	"os"
+	"strconv"
+
+	"github.com/godbus/dbus/v5"
+)
+
+const (
+	dbusDest = "org.freedesktop.hostname1"
+	dbusPath = "/org/freedesktop/hostname1"
+)
+
+// Conn is a connection to systemds dbus endpoint.
+type Conn struct {
+	conn   *dbus.Conn
+	object dbus.BusObject
+}
+
+// New establishes a connection to the system bus and authenticates.
+func New() (*Conn, error) {
+	c := new(Conn)
+
+	if err := c.initConnection(); err != nil {
+		return nil, err
+	}
+
+	return c, nil
+}
+
+// Close closes the dbus connection
+func (c *Conn) Close() {
+	if c == nil {
+		return
+	}
+
+	if c.conn != nil {
+		c.conn.Close()
+	}
+}
+
+// Connected returns whether conn is connected
+func (c *Conn) Connected() bool {
+	return c.conn.Connected()
+}
+
+func (c *Conn) initConnection() error {
+	var err error
+	if c.conn, err = dbus.SystemBusPrivate(); err != nil {
+		return err
+	}
+
+	// Only use EXTERNAL method, and hardcode the uid (not username)
+	// to avoid a username lookup (which requires a dynamically linked
+	// libc)
+	methods := []dbus.Auth{dbus.AuthExternal(strconv.Itoa(os.Getuid()))}
+
+	if err := c.conn.Auth(methods); err != nil {
+		c.conn.Close()
+		return err
+	}
+
+	if err := c.conn.Hello(); err != nil {
+		c.conn.Close()
+		return err
+	}
+
+	c.object = c.conn.Object(dbusDest, dbus.ObjectPath(dbusPath))
+
+	return nil
+}
+
+func (c *Conn) SetHostname(hostname string, interactive bool) error {
+	return c.object.Call(dbusDest+".SetHostname", 0, hostname, interactive).Err
+}
+
+func (c *Conn) SetStaticHostname(hostname string, interactive bool) error {
+	return c.object.Call(dbusDest+".SetStaticHostname", 0, hostname, interactive).Err
+}
+
+func (c *Conn) SetPrettyHostname(hostname string, interactive bool) error {
+	return c.object.Call(dbusDest+".SetPrettyHostname", 0, hostname, interactive).Err
+}
+
+func (c *Conn) SetIconName(iconName string, interactive bool) error {
+	return c.object.Call(dbusDest+".SetIconName", 0, iconName, interactive).Err
+}
+
+func (c *Conn) SetChassis(chassis string, interactive bool) error {
+	return c.object.Call(dbusDest+".SetChassis", 0, chassis, interactive).Err
+}
+
+func (c *Conn) SetDeployment(deployment string, interactive bool) error {
+	return c.object.Call(dbusDest+".SetDeployment", 0, deployment, interactive).Err
+}
+
+func (c *Conn) SetLocation(location string, interactive bool) error {
+	return c.object.Call(dbusDest+".SetLocation", 0, location, interactive).Err
+}
+
+func (c *Conn) GetProductUUID(interactive bool) ([]byte, error) {
+	var uuid []byte
+	err := c.object.Call(dbusDest+".GetProductUUID", 0, interactive).Store(&uuid)
+	return uuid, err
+}
+
+func (c *Conn) GetHardwareSerial() (string, error) {
+	var serial string
+	err := c.object.Call(dbusDest+".GetHardwareSerial", 0).Store(&serial)
+	return serial, err
+}
+
+func (c *Conn) Describe() (string, error) {
+	var description string
+	err := c.object.Call(dbusDest+".Describe", 0).Store(&description)
+	return description, err
+}
+
+func (c *Conn) Hostname() (string, error) {
+	out, err := c.object.GetProperty(dbusDest + ".Hostname")
+	if err != nil {
+		return "", err
+	}
+	return out.Value().(string), nil
+}
+
+func (c *Conn) StaticHostname() (string, error) {
+	out, err := c.object.GetProperty(dbusDest + ".StaticHostname")
+	if err != nil {
+		return "", err
+	}
+	return out.Value().(string), nil
+}
+
+func (c *Conn) PrettyHostname() (string, error) {
+	out, err := c.object.GetProperty(dbusDest + ".PrettyHostname")
+	if err != nil {
+		return "", err
+	}
+	return out.Value().(string), nil
+}
+
+func (c *Conn) DefaultHostname() (string, error) {
+	out, err := c.object.GetProperty(dbusDest + ".DefaultHostname")
+	if err != nil {
+		return "", err
+	}
+	return out.Value().(string), nil
+}
+
+func (c *Conn) HostnameSource() (string, error) {
+	out, err := c.object.GetProperty(dbusDest + ".HostnameSource")
+	if err != nil {
+		return "", err
+	}
+	return out.Value().(string), nil
+}
+
+func (c *Conn) IconName() (string, error) {
+	out, err := c.object.GetProperty(dbusDest + ".IconName")
+	if err != nil {
+		return "", err
+	}
+	return out.Value().(string), nil
+}
+
+func (c *Conn) Chassis() (string, error) {
+	out, err := c.object.GetProperty(dbusDest + ".Chassis")
+	if err != nil {
+		return "", err
+	}
+	return out.Value().(string), nil
+}
+
+func (c *Conn) Deployment() (string, error) {
+	out, err := c.object.GetProperty(dbusDest + ".Deployment")
+	if err != nil {
+		return "", err
+	}
+	return out.Value().(string), nil
+}
+
+func (c *Conn) Location() (string, error) {
+	out, err := c.object.GetProperty(dbusDest + ".Location")
+	if err != nil {
+		return "", err
+	}
+	return out.Value().(string), nil
+}
+
+func (c *Conn) KernelName() (string, error) {
+	out, err := c.object.GetProperty(dbusDest + ".KernelName")
+	if err != nil {
+		return "", err
+	}
+	return out.Value().(string), nil
+}
+
+func (c *Conn) KernelRelease() (string, error) {
+	out, err := c.object.GetProperty(dbusDest + ".KernelRelease")
+	if err != nil {
+		return "", err
+	}
+	return out.Value().(string), nil
+}
+
+func (c *Conn) KernelVersion() (string, error) {
+	out, err := c.object.GetProperty(dbusDest + ".KernelVersion")
+	if err != nil {
+		return "", err
+	}
+	return out.Value().(string), nil
+}
+
+func (c *Conn) OperatingSystemPrettyName() (string, error) {
+	out, err := c.object.GetProperty(dbusDest + ".OperatingSystemPrettyName")
+	if err != nil {
+		return "", err
+	}
+	return out.Value().(string), nil
+}
+
+func (c *Conn) OperatingSystemCPEName() (string, error) {
+	out, err := c.object.GetProperty(dbusDest + ".OperatingSystemCPEName")
+	if err != nil {
+		return "", err
+	}
+	return out.Value().(string), nil
+}
+
+func (c *Conn) OperatingSystemSupportEnd() (uint64, error) {
+	out, err := c.object.GetProperty(dbusDest + ".OperatingSystemSupportEnd")
+	if err != nil {
+		return 0, err
+	}
+	return out.Value().(uint64), nil
+}
+
+func (c *Conn) HomeURL() (string, error) {
+	out, err := c.object.GetProperty(dbusDest + ".HomeURL")
+	if err != nil {
+		return "", err
+	}
+	return out.Value().(string), nil
+}
+
+func (c *Conn) HardwareVendor() (string, error) {
+	out, err := c.object.GetProperty(dbusDest + ".HardwareVendor")
+	if err != nil {
+		return "", err
+	}
+	return out.Value().(string), nil
+}
+
+func (c *Conn) HardwareModel() (string, error) {
+	out, err := c.object.GetProperty(dbusDest + ".HardwareModel")
+	if err != nil {
+		return "", err
+	}
+	return out.Value().(string), nil
+}
+
+func (c *Conn) FirmwareVersion() (string, error) {
+	out, err := c.object.GetProperty(dbusDest + ".FirmwareVersion")
+	if err != nil {
+		return "", err
+	}
+	return out.Value().(string), nil
+}
+
+func (c *Conn) FirmwareVendor() (string, error) {
+	out, err := c.object.GetProperty(dbusDest + ".FirmwareVendor")
+	if err != nil {
+		return "", err
+	}
+	return out.Value().(string), nil
+}
+
+func (c *Conn) FirmwareDate() (uint64, error) {
+	out, err := c.object.GetProperty(dbusDest + ".FirmwareDate")
+	if err != nil {
+		return 0, err
+	}
+	return out.Value().(uint64), nil
+}

hostname1/dbus_test.go

@@ -0,0 +1,76 @@
+// Copyright 2015 CoreOS, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+package hostname1
+
+import (
+	"io"
+	"os"
+	"os/exec"
+	"strings"
+	"testing"
+)
+
+// TestNew ensures that New() works without errors.
+func TestNew(t *testing.T) {
+	if _, err := New(); err != nil {
+		t.Fatal(err)
+	}
+}
+
+// TestHostname ensures that the Hostname() method returns the system hostname.
+func TestHostname(t *testing.T) {
+	expectedHostname, err := exec.Command("hostname").CombinedOutput()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	h, err := New()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if hostname, err := h.Hostname(); err != nil {
+		t.Fatal(err)
+	} else if hostname != strings.TrimSuffix(string(expectedHostname), "\n") {
+		t.Fatalf("expected %q, got %q", expectedHostname, hostname)
+	}
+}
+
+func TestStaticHostname(t *testing.T) {
+	hostnameFile, err := os.Open("/etc/hostname")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer hostnameFile.Close()
+
+	expectedHostnameBytes := make([]byte, 256)
+	n, err := hostnameFile.Read(expectedHostnameBytes)
+	if err != nil && err != io.EOF {
+		t.Fatal(err)
+	}
+	// Close the file so that hostnamed can use it.
+	hostnameFile.Close()
+	expectedHostname := strings.TrimSuffix(string(expectedHostnameBytes[:n]), "\n")
+
+	h, err := New()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if hostname, err := h.StaticHostname(); err != nil {
+		t.Fatal(err)
+	} else if hostname != expectedHostname {
+		t.Fatalf("expected %q, got %q", expectedHostname, hostname)
+	}
+}