libcontainer: Replace GetProcessStartTime with Stat_t.StartTime

And convert the various start-time properties from strings to uint64s.
This removes all internal consumers of the deprecated
GetProcessStartTime function.

Signed-off-by: W. Trevor King <wking@tremily.us>

libcontainer/container.go

@@ -54,7 +54,7 @@ type BaseState struct {
 	InitProcessPid int `json:"init_process_pid"`
 
 	// InitProcessStartTime is the init process start time in clock cycles since boot time.
-	InitProcessStartTime string `json:"init_process_start"`
+	InitProcessStartTime uint64 `json:"init_process_start"`
 
 	// Created is the unix timestamp for the creation time of the container in UTC
 	Created time.Time `json:"created"`

libcontainer/container_linux.go

@@ -40,7 +40,7 @@ type linuxContainer struct {
 	cgroupManager        cgroups.Manager
 	initArgs             []string
 	initProcess          parentProcess
-	initProcessStartTime string
+	initProcessStartTime uint64
 	criuPath             string
 	m                    sync.Mutex
 	criuVersion          int
@@ -1370,11 +1370,11 @@ func (c *linuxContainer) refreshState() error {
 // and a new process has been created with the same pid, in this case, the
 // container would already be stopped.
 func (c *linuxContainer) doesInitProcessExist(initPid int) (bool, error) {
-	startTime, err := system.GetProcessStartTime(initPid)
+	stat, err := system.Stat(initPid)
 	if err != nil {
-		return false, newSystemErrorWithCausef(err, "getting init process %d start time", initPid)
+		return false, newSystemErrorWithCausef(err, "getting init process %d status", initPid)
 	}
-	if c.initProcessStartTime != startTime {
+	if c.initProcessStartTime != stat.StartTime {
 		return false, nil
 	}
 	return true, nil
@@ -1427,7 +1427,7 @@ func (c *linuxContainer) isPaused() (bool, error) {
 
 func (c *linuxContainer) currentState() (*State, error) {
 	var (
-		startTime           string
+		startTime           uint64
 		externalDescriptors []string
 		pid                 = -1
 	)

libcontainer/container_linux_test.go

@@ -52,7 +52,7 @@ func (m *mockCgroupManager) Freeze(state configs.FreezerState) error {
 
 type mockProcess struct {
 	_pid    int
-	started string
+	started uint64
 }
 
 func (m *mockProcess) terminate() error {
@@ -63,7 +63,7 @@ func (m *mockProcess) pid() int {
 	return m._pid
 }
 
-func (m *mockProcess) startTime() (string, error) {
+func (m *mockProcess) startTime() (uint64, error) {
 	return m.started, nil
 }
 
@@ -150,7 +150,7 @@ func TestGetContainerState(t *testing.T) {
 		},
 		initProcess: &mockProcess{
 			_pid:    pid,
-			started: "010",
+			started: 10,
 		},
 		cgroupManager: &mockCgroupManager{
 			pids: []int{1, 2, 3},
@@ -174,8 +174,8 @@ func TestGetContainerState(t *testing.T) {
 	if state.InitProcessPid != pid {
 		t.Fatalf("expected pid %d but received %d", pid, state.InitProcessPid)
 	}
-	if state.InitProcessStartTime != "010" {
-		t.Fatalf("expected process start time 010 but received %s", state.InitProcessStartTime)
+	if state.InitProcessStartTime != 10 {
+		t.Fatalf("expected process start time 10 but received %d", state.InitProcessStartTime)
 	}
 	paths := state.CgroupPaths
 	if paths == nil {

libcontainer/process_linux.go

@@ -35,7 +35,7 @@ type parentProcess interface {
 	wait() (*os.ProcessState, error)
 
 	// startTime returns the process start time.
-	startTime() (string, error)
+	startTime() (uint64, error)
 
 	signal(os.Signal) error
 
@@ -55,8 +55,9 @@ type setnsProcess struct {
 	bootstrapData io.Reader
 }
 
-func (p *setnsProcess) startTime() (string, error) {
-	return system.GetProcessStartTime(p.pid())
+func (p *setnsProcess) startTime() (uint64, error) {
+	stat, err := system.Stat(p.pid())
+	return stat.StartTime, err
 }
 
 func (p *setnsProcess) signal(sig os.Signal) error {
@@ -384,8 +385,9 @@ func (p *initProcess) terminate() error {
 	return err
 }
 
-func (p *initProcess) startTime() (string, error) {
-	return system.GetProcessStartTime(p.pid())
+func (p *initProcess) startTime() (uint64, error) {
+	stat, err := system.Stat(p.pid())
+	return stat.StartTime, err
 }
 
 func (p *initProcess) sendConfig() error {

libcontainer/restored_process.go

@@ -17,20 +17,20 @@ func newRestoredProcess(pid int, fds []string) (*restoredProcess, error) {
 	if err != nil {
 		return nil, err
 	}
-	started, err := system.GetProcessStartTime(pid)
+	stat, err := system.Stat(pid)
 	if err != nil {
 		return nil, err
 	}
 	return &restoredProcess{
 		proc:             proc,
-		processStartTime: started,
+		processStartTime: stat.StartTime,
 		fds:              fds,
 	}, nil
 }
 
 type restoredProcess struct {
 	proc             *os.Process
-	processStartTime string
+	processStartTime uint64
 	fds              []string
 }
 
@@ -60,7 +60,7 @@ func (p *restoredProcess) wait() (*os.ProcessState, error) {
 	return st, nil
 }
 
-func (p *restoredProcess) startTime() (string, error) {
+func (p *restoredProcess) startTime() (uint64, error) {
 	return p.processStartTime, nil
 }
 
@@ -81,7 +81,7 @@ func (p *restoredProcess) setExternalDescriptors(newFds []string) {
 // a persisted state.
 type nonChildProcess struct {
 	processPid       int
-	processStartTime string
+	processStartTime uint64
 	fds              []string
 }
 
@@ -101,7 +101,7 @@ func (p *nonChildProcess) wait() (*os.ProcessState, error) {
 	return nil, newGenericError(fmt.Errorf("restored process cannot be waited on"), SystemError)
 }
 
-func (p *nonChildProcess) startTime() (string, error) {
+func (p *nonChildProcess) startTime() (uint64, error) {
 	return p.processStartTime, nil
 }