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// 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 MachineName is a name representing a locally running container or
// virtual machine that is registerd with (systemd-)machined.
type MachineName string
func (m MachineName) 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() ([]MachineName, error) {
strs, err := get_files_in_directory("/run/systemd/machines/")
if err != nil {
return nil, err
}
var machines []MachineName
for _, str := range strs {
machine := MachineName(str)
if strings.HasPrefix(str, "unit:") || machine.isValid() {
continue
}
machines = append(machines, machine)
}
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 MachineName) 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 MachineName) 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
}
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