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package main
import (
"bytes"
"net"
"os"
"path"
"path/filepath"
"strconv"
"time"
"github.com/opencontainers/runc/libcontainer"
"github.com/opencontainers/runtime-spec/specs-go"
"github.com/urfave/cli"
)
type notifySocket struct {
socket *net.UnixConn
host string
socketPath string
}
func newNotifySocket(context *cli.Context, notifySocketHost string, id string) *notifySocket {
if notifySocketHost == "" {
return nil
}
root := filepath.Join(context.GlobalString("root"), id)
socketPath := filepath.Join(root, "notify", "notify.sock")
notifySocket := ¬ifySocket{
socket: nil,
host: notifySocketHost,
socketPath: socketPath,
}
return notifySocket
}
func (s *notifySocket) Close() error {
return s.socket.Close()
}
// If systemd is supporting sd_notify protocol, this function will add support
// for sd_notify protocol from within the container.
func (s *notifySocket) setupSpec(spec *specs.Spec) {
pathInContainer := filepath.Join("/run/notify", path.Base(s.socketPath))
mount := specs.Mount{
Destination: path.Dir(pathInContainer),
Source: path.Dir(s.socketPath),
Options: []string{"bind", "nosuid", "noexec", "nodev", "ro"},
}
spec.Mounts = append(spec.Mounts, mount)
spec.Process.Env = append(spec.Process.Env, "NOTIFY_SOCKET="+pathInContainer)
}
func (s *notifySocket) bindSocket() error {
addr := net.UnixAddr{
Name: s.socketPath,
Net: "unixgram",
}
socket, err := net.ListenUnixgram("unixgram", &addr)
if err != nil {
return err
}
err = os.Chmod(s.socketPath, 0o777)
if err != nil {
socket.Close()
return err
}
s.socket = socket
return nil
}
func (s *notifySocket) setupSocketDirectory() error {
return os.Mkdir(path.Dir(s.socketPath), 0o755)
}
func notifySocketStart(context *cli.Context, notifySocketHost, id string) (*notifySocket, error) {
notifySocket := newNotifySocket(context, notifySocketHost, id)
if notifySocket == nil {
return nil, nil
}
if err := notifySocket.bindSocket(); err != nil {
return nil, err
}
return notifySocket, nil
}
func (n *notifySocket) waitForContainer(container libcontainer.Container) error {
s, err := container.State()
if err != nil {
return err
}
return n.run(s.InitProcessPid)
}
func (n *notifySocket) run(pid1 int) error {
if n.socket == nil {
return nil
}
notifySocketHostAddr := net.UnixAddr{Name: n.host, Net: "unixgram"}
client, err := net.DialUnix("unixgram", nil, ¬ifySocketHostAddr)
if err != nil {
return err
}
ticker := time.NewTicker(time.Millisecond * 100)
defer ticker.Stop()
fileChan := make(chan []byte)
go func() {
for {
buf := make([]byte, 4096)
r, err := n.socket.Read(buf)
if err != nil {
return
}
got := buf[0:r]
// systemd-ready sends a single datagram with the state string as payload,
// so we don't need to worry about partial messages.
for _, line := range bytes.Split(got, []byte{'\n'}) {
if bytes.HasPrefix(got, []byte("READY=")) {
fileChan <- line
return
}
}
}
}()
for {
select {
case <-ticker.C:
_, err := os.Stat(filepath.Join("/proc", strconv.Itoa(pid1)))
if err != nil {
return nil
}
case b := <-fileChan:
var out bytes.Buffer
_, err = out.Write(b)
if err != nil {
return err
}
_, err = out.Write([]byte{'\n'})
if err != nil {
return err
}
_, err = client.Write(out.Bytes())
if err != nil {
return err
}
// now we can inform systemd to use pid1 as the pid to monitor
newPid := "MAINPID=" + strconv.Itoa(pid1)
_, err := client.Write([]byte(newPid + "\n"))
if err != nil {
return err
}
return nil
}
}
}
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