catch SIGCHLD signals

sigchld_unix.go

@@ -3,17 +3,35 @@
 package main
 
 import (
+	"log"
+	"os"
+	"os/signal"
 	"syscall"
-
-	"github.com/qiniu/log"
 )
 
 func init() {
 	go reapChildren()
 }
 
+func childSignal(notify chan bool) {
+	var sigs = make(chan os.Signal, 3)
+	signal.Notify(sigs, syscall.SIGCHLD)
+
+	for {
+		<-sigs
+		select {
+		case notify <- true:
+		default:
+			// Channel full, does not matter as we wait for all children.
+		}
+	}
+}
+
 func reapChildren() {
 	var wstatus syscall.WaitStatus
+	notify := make(chan bool, 1)
+
+	go childSignal(notify)
 
 	for {
 		pid, err := syscall.Wait4(-1, &wstatus, 0, nil)