wgengine/monitor: prevent shutdown hang in darwin link monitor
import (
"bufio"
+ "errors"
"os/exec"
+ "tailscale.com/syncs"
"tailscale.com/types/logger"
)
@@ -29,12 +31,14 @@ func newOSMon(logf logger.Logf) (osMon, error) {
// we can just shell out to "route -n monitor". It waits for any input
// but doesn't parse it. Then we poll to see if something is different.
type routeMonitorSubProcMon struct {
+ closed syncs.AtomicBool
cmd *exec.Cmd // of "/sbin/route -n monitor"
br *bufio.Reader
buf []byte
}
func (m *routeMonitorSubProcMon) Close() error {
+ m.closed.Set(true)
if m.cmd != nil {
m.cmd.Process.Kill()
m.cmd = nil
@@ -43,6 +47,9 @@ func (m *routeMonitorSubProcMon) Close() error {
}
func (m *routeMonitorSubProcMon) Receive() (message, error) {
+ if m.closed.Get() {
+ return nil, errors.New("monitor closed")
+ }
if m.cmd == nil {
cmd := exec.Command("/sbin/route", "-n", "monitor")
outPipe, err := cmd.StdoutPipe()
