handle closed listeners

gracenet/net.go

@@ -31,10 +31,11 @@ var originalWD, _ = os.Getwd()
 // Net provides the family of Listen functions and maintains the associated
 // state. Typically you will have only once instance of Net per application.
 type Net struct {
- inherited []net.Listener
- active []net.Listener
- mutex sync.Mutex
- inheritOnce sync.Once
+ inherited []net.Listener
+ active []net.Listener
+ closedListeners []net.Listener
+ mutex sync.Mutex
+ inheritOnce sync.Once
 
  // used in tests to override the default behavior of starting from fd 3.
  fdStart int
@@ -168,6 +169,13 @@ func (n *Net) ListenUnix(nett string, laddr *net.UnixAddr) (*net.UnixListener, e
  return l, nil
 }
 
+func (n *Net) Close(l net.Listener) {
+ n.mutex.Lock()
+ defer n.mutex.Unlock()
+ n.closedListeners = append(n.closedListeners, l)
+ l.Close()
+}
+
 // activeListeners returns a snapshot copy of the active listeners.
 func (n *Net) activeListeners() ([]net.Listener, error) {
  n.mutex.Lock()
@@ -209,14 +217,31 @@ func (n *Net) StartProcess() (int, error) {
  return 0, err
  }
 
+ n.mutex.Lock()
+ closedList := make([]net.Addr, len(n.closedListeners))
+ for i, l := range n.closedListeners {
+ closedList[i] = l.Addr()
+ }
+ n.mutex.Unlock()
  // Extract the fds from the listeners.
- files := make([]*os.File, len(listeners))
- for i, l := range listeners {
- files[i], err = l.(filer).File()
+ files := make([]*os.File, 0, len(listeners)-len(closedList))
+ for _, l := range listeners {
+ is_closed := false
+ for _, closedAddr := range closedList {
+ if isSameAddr(l.Addr(), closedAddr) {
+ is_closed = true
+ break
+ }
+ }
+ if is_closed {
+ continue
+ }
+ f, err := l.(filer).File()
  if err != nil {
  return 0, err
  }
- defer files[i].Close()
+ files = append(files, f)
+ defer f.Close()
  }
 
  // Use the original binary location. This works with symlinks such that if
@@ -233,7 +258,7 @@ func (n *Net) StartProcess() (int, error) {
  env = append(env, v)
  }
  }
- env = append(env, fmt.Sprintf("%s%d", envCountKeyPrefix, len(listeners)))
+ env = append(env, fmt.Sprintf("%s%d", envCountKeyPrefix, len(files)))
 
  allFiles := append([]*os.File{os.Stdin, os.Stdout, os.Stderr}, files...)
  process, err := os.StartProcess(argv0, os.Args, &os.ProcAttr{