Merge pull request #4867 from crosbymichael/clean-shutdown

Cleanly shutdown docker

libcontainer/nsinit/exec.go

@@ -50,8 +50,13 @@ func (ns *linuxNs) Exec(container *libcontainer.Container, term Terminal, args [
 	if err := command.Start(); err != nil {
 		return -1, err
 	}
+
+	started, err := system.GetProcessStartTime(command.Process.Pid)
+	if err != nil {
+		return -1, err
+	}
 	ns.logger.Printf("writting pid %d to file\n", command.Process.Pid)
-	if err := ns.stateWriter.WritePid(command.Process.Pid); err != nil {
+	if err := ns.stateWriter.WritePid(command.Process.Pid, started); err != nil {
 		command.Process.Kill()
 		return -1, err
 	}

libcontainer/nsinit/init.go

@@ -54,11 +54,6 @@ func (ns *linuxNs) Init(container *libcontainer.Container, uncleanRootfs, consol
 			return fmt.Errorf("setctty %s", err)
 		}
 	}
-	// this is our best effort to let the process know that the parent has died and that it
-	// should it should act on it how it sees fit
-	if err := system.ParentDeathSignal(uintptr(syscall.SIGTERM)); err != nil {
-		return fmt.Errorf("parent death signal %s", err)
-	}
 	if err := setupNetwork(container, context); err != nil {
 		return fmt.Errorf("setup networking %s", err)
 	}

libcontainer/nsinit/state.go

@@ -10,7 +10,7 @@ import (
 // StateWriter handles writing and deleting the pid file
 // on disk
 type StateWriter interface {
-	WritePid(pid int) error
+	WritePid(pid int, startTime string) error
 	DeletePid() error
 }
 
@@ -19,10 +19,18 @@ type DefaultStateWriter struct {
 }
 
 // writePidFile writes the namespaced processes pid to pid in the rootfs for the container
-func (d *DefaultStateWriter) WritePid(pid int) error {
+func (d *DefaultStateWriter) WritePid(pid int, startTime string) error {
-	return ioutil.WriteFile(filepath.Join(d.Root, "pid"), []byte(fmt.Sprint(pid)), 0655)
+	err := ioutil.WriteFile(filepath.Join(d.Root, "pid"), []byte(fmt.Sprint(pid)), 0655)
+	if err != nil {
+		return err
+	}
+	return ioutil.WriteFile(filepath.Join(d.Root, "start"), []byte(startTime), 0655)
 }
 
 func (d *DefaultStateWriter) DeletePid() error {
-	return os.Remove(filepath.Join(d.Root, "pid"))
+	err := os.Remove(filepath.Join(d.Root, "pid"))
+	if serr := os.Remove(filepath.Join(d.Root, "start")); err == nil {
+		err = serr
+	}
+	return err
 }

system/proc.go

@@ -0,0 +1,26 @@
+package system
+
+import (
+	"io/ioutil"
+	"path/filepath"
+	"strconv"
+	"strings"
+)
+
+// look in /proc to find the process start time so that we can verify
+// that this pid has started after ourself
+func GetProcessStartTime(pid int) (string, error) {
+	data, err := ioutil.ReadFile(filepath.Join("/proc", strconv.Itoa(pid), "stat"))
+	if err != nil {
+		return "", err
+	}
+	parts := strings.Split(string(data), " ")
+	// the starttime is located at pos 22
+	// from the man page
+	//
+	// starttime %llu (was %lu before Linux 2.6)
+	// (22)  The  time the process started after system boot.  In kernels before Linux 2.6, this
+	// value was expressed in jiffies.  Since Linux 2.6, the value is expressed in  clock  ticks
+	// (divide by sysconf(_SC_CLK_TCK)).
+	return parts[22-1], nil // starts at 1
+}