1 files changed, 122 insertions, 0 deletions
diff --git a/sd_login/machined_machine.go b/sd_login/machined_machine.go
new file mode 100644
index 0000000..d89eaad
--- /dev/null
+++ b/sd_login/machined_machine.go
@@ -0,0 +1,122 @@
+// Copyright (C) 2016-2017 Luke Shumaker <lukeshu@sbcglobal.net>
+//
+// 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 sd_login
+
+import (
+	"strconv"
+	"strings"
+
+	"golang.org/x/sys/unix"
+)
+
+// A Machine is a name representing a locally running container or
+// virtual machine that is registerd with (systemd-)machined.
+type Machine string
+
+// isValid returns whether the Machine name is valid.
+func (m Machine) isValid() bool {
+	if len(m) > host_name_max {
+		// Note that Linux HOST_NAME_MAX is 64, but DNS allows
+		// 255, so names from DNS might be invalid.
+		return false
+	}
+
+	n_dots := 0
+	dot := true
+	for _, c := range m {
+		if c == '.' {
+			if dot {
+				return false
+			}
+			dot = true
+			n_dots++
+		} else {
+			if !strings.ContainsRune(letters+digits+"-_.", c) {
+				return false
+			}
+			dot = false
+		}
+	}
+
+	if dot { // trailing dot or empty
+		return false
+	}
+
+	return true
+}
+
+// GetMachines returns a list of currently running containers/virtual
+// machines.
+func GetMachines() ([]Machine, error) {
+	strs, err := get_files_in_directory("/run/systemd/machines/")
+	if err != nil {
+		return nil, err
+	}
+	var machines []Machine
+	for _, str := range strs {
+		machine := Machine(str)
+		if strings.HasPrefix(str, "unit:") || machine.isValid() {
+			continue
+		}
+		machines = append(machines, Machine(str))
+	}
+	return machines, nil
+}
+
+// GetClass returns the class of a locally running machine.  The class
+// is either "vm" or "container", depending on if the machine is an
+// virtual machine or a container.
+func (m Machine) GetClass() (string, error) {
+	if !m.isValid() {
+		return "", unix.EINVAL
+	}
+
+	env, err := parse_env_file("/run/systemd/machines/" + string(m))
+	if err != nil {
+		return "", err
+	}
+	class, ok := env["CLASS"]
+	if !ok {
+		return "", unix.ENXIO // or EIO?
+	}
+	return class, nil
+}
+
+// GetIfIndices returns the numeric indices of the network interfaces
+// on the host that are pointing toward this machine.
+func (m Machine) GetIfIndices() ([]int, error) {
+	if !m.isValid() {
+		return nil, unix.EINVAL
+	}
+
+	env, err := parse_env_file("/run/systemd/machines/" + string(m))
+	if err != nil {
+		return nil, err
+	}
+	netif, ok := env["NETIF"]
+	if !ok {
+		return nil, unix.ENXIO // or EIO?
+	}
+
+	var ifindices []int
+	for _, word := range strings.FieldsFunc(netif, func(c rune) bool { return strings.ContainsRune(whitespace, c) }) {
+		ifindex, err := strconv.Atoi(word)
+		if err != nil {
+			return nil, err
+		}
+		ifindices = append(ifindices, ifindex)
+	}
+	return ifindices, nil
+}