From 58861a7cbcd8f745ec0cc99e7dced13da07eff68 Mon Sep 17 00:00:00 2001
From: Luke Shumaker <lukeshu@sbcglobal.net>
Date: Wed, 18 Jan 2017 22:24:27 -0500
Subject: initial commit

---
 systemd-timesyncd-wrap.go | 98 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 98 insertions(+)
 create mode 100644 systemd-timesyncd-wrap.go

(limited to 'systemd-timesyncd-wrap.go')

diff --git a/systemd-timesyncd-wrap.go b/systemd-timesyncd-wrap.go
new file mode 100644
index 0000000..3d5971b
--- /dev/null
+++ b/systemd-timesyncd-wrap.go
@@ -0,0 +1,98 @@
+package main
+
+import (
+	"net"
+	"os"
+	"strings"
+	"sync"
+	"syscall"
+)
+
+func socketUnixgram(name string) (*net.UnixConn, error) {
+	fd, err := syscall.Socket(syscall.AF_UNIX, syscall.SOCK_DGRAM|syscall.SOCK_CLOEXEC, 0)
+	if err != nil {
+		return nil, err
+	}
+	conn, err := net.FileConn(os.NewFile(uintptr(fd), name))
+	if err != nil {
+		return nil, err
+	}
+	unixConn := conn.(*net.UnixConn)
+	return unixConn, nil
+}
+
+func sendmsg(dat, oob []byte, sockname string) error {
+	writer, err := socketUnixgram(sockname)
+	if err != nil {
+		return err
+	}
+	_, _, err = writer.WriteMsgUnix(dat, oob, &net.UnixAddr{Net: "unixgram", Name: sockname})
+	return err
+}
+
+func main() {
+	sync_sockname := "/run/timesyncd/time-sync.sock"
+	fake_sockname := "/run/timesyncd/notify.sock"
+	real_sockname := os.Getenv("NOTIFY_SOCKET")
+
+	fake_sock, err := net.ListenUnixgram("unixgram", &net.UnixAddr{Net: "unixgram", Name: fake_sockname})
+	if err != nil {
+		os.Stderr.WriteString(err.Error())
+		os.Stderr.Write([]byte{'\n'})
+		os.Exit(127)
+	}
+
+	os.Setenv("NOTIFY_SOCKET", fake_sockname)
+	proc, err := os.StartProcess(os.Args[1], os.Args[1:], &os.ProcAttr{})
+	if err != nil {
+		os.Stderr.WriteString(err.Error())
+		os.Stderr.Write([]byte{'\n'})
+		os.Exit(127)
+	}
+
+	var wg sync.WaitGroup
+	wg.Add(1)
+	go func() {
+		synced := false
+		var dat [4096]byte
+		oob := make([]byte, syscall.CmsgSpace(syscall.SizeofUcred)+syscall.CmsgSpace(8*768))
+		for {
+			n, oobn, flags, _, err := fake_sock.ReadMsgUnix(dat[:], oob[:])
+			if err != nil {
+				break
+			}
+			if flags&syscall.MSG_TRUNC != 0 {
+				continue
+			}
+			if !synced {
+				for _, line := range strings.Split(string(dat[:n]), "\n") {
+					if strings.HasPrefix(line, "STATUS=Synchronized") {
+						_ = sendmsg([]byte(line), nil, sync_sockname)
+						synced = true
+						break
+					}
+				}
+			}
+			_ = sendmsg(dat[:n], oob[:oobn], real_sockname)
+		}
+		wg.Done()
+	}()
+
+	state, err := proc.Wait()
+	_ = fake_sock.Close()
+	wg.Wait()
+
+	if err != nil {
+		os.Stderr.WriteString(err.Error())
+		os.Stderr.Write([]byte{'\n'})
+		os.Exit(127)
+	}
+	status := state.Sys().(syscall.WaitStatus)
+	if status.Exited() {
+		os.Exit(status.ExitStatus())
+	}
+	if status.Signaled() {
+		self, _ := os.FindProcess(os.Getpid())
+		self.Signal(status.Signal())
+	}
+}
-- 
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