Merge pull request #2798 from dotcloud/fix_state_race

Refactor State to be 100% thread safe

commands.go

@@ -1543,7 +1543,7 @@ func (cli *DockerCli) CmdAttach(args ...string) error {
 		return err
 	}
 
-	if !container.State.Running {
+	if !container.State.IsRunning() {
 		return fmt.Errorf("Impossible to attach to a stopped container, start it first")
 	}
 
@@ -2517,7 +2517,7 @@ func getExitCode(cli *DockerCli, containerId string) (bool, int, error) {
 	if err := json.Unmarshal(body, c); err != nil {
 		return false, -1, err
 	}
-	return c.State.Running, c.State.ExitCode, nil
+	return c.State.IsRunning(), c.State.GetExitCode(), nil
 }
 
 func NewDockerCli(in io.ReadCloser, out, err io.Writer, proto, addr string) *DockerCli {

container.go

@@ -19,11 +19,14 @@ import (
 	"path/filepath"
 	"strconv"
 	"strings"
+	"sync"
 	"syscall"
 	"time"
 )
 
 type Container struct {
+	sync.Mutex
+
 	root string
 
 	ID string
@@ -487,9 +490,10 @@ func (container *Container) Attach(stdin io.ReadCloser, stdinCloser io.Closer, s
 }
 
 func (container *Container) Start() (err error) {
-	container.State.Lock()
+	container.Lock()
-	defer container.State.Unlock()
+	defer container.Unlock()
-	if container.State.Running {
+
+	if container.State.IsRunning() {
 		return fmt.Errorf("The container %s is already running.", container.ID)
 	}
 	defer func() {
@@ -818,7 +822,7 @@ func (container *Container) Start() (err error) {
 	}
 	// FIXME: save state on disk *first*, then converge
 	// this way disk state is used as a journal, eg. we can restore after crash etc.
-	container.State.setRunning(container.cmd.Process.Pid)
+	container.State.SetRunning(container.cmd.Process.Pid)
 
 	// Init the lock
 	container.waitLock = make(chan struct{})
@@ -826,14 +830,14 @@ func (container *Container) Start() (err error) {
 	container.ToDisk()
 	go container.monitor()
 
-	defer utils.Debugf("Container running: %v", container.State.Running)
+	defer utils.Debugf("Container running: %v", container.State.IsRunning())
 	// We wait for the container to be fully running.
 	// Timeout after 5 seconds. In case of broken pipe, just retry.
 	// Note: The container can run and finish correctly before
 	//       the end of this loop
 	for now := time.Now(); time.Since(now) < 5*time.Second; {
 		// If the container dies while waiting for it, just return
-		if !container.State.Running {
+		if !container.State.IsRunning() {
 			return nil
 		}
 		output, err := exec.Command("lxc-info", "-s", "-n", container.ID).CombinedOutput()
@@ -850,11 +854,11 @@ func (container *Container) Start() (err error) {
 		if strings.Contains(string(output), "RUNNING") {
 			return nil
 		}
-		utils.Debugf("Waiting for the container to start (running: %v): %s", container.State.Running, bytes.TrimSpace(output))
+		utils.Debugf("Waiting for the container to start (running: %v): %s", container.State.IsRunning(), bytes.TrimSpace(output))
 		time.Sleep(50 * time.Millisecond)
 	}
 
-	if container.State.Running {
+	if container.State.IsRunning() {
 		return ErrContainerStartTimeout
 	}
 	return ErrContainerStart
@@ -935,11 +939,12 @@ func (container *Container) allocateNetwork() error {
 		return nil
 	}
 
-	var iface *NetworkInterface
+	var (
-	var err error
+		iface *NetworkInterface
-	if container.State.Ghost {
+		err   error
-		manager := container.runtime.networkManager
+	)
-		if manager.disabled {
+	if container.State.IsGhost() {
+		if manager := container.runtime.networkManager; manager.disabled {
 			iface = &NetworkInterface{disabled: true}
 		} else {
 			iface = &NetworkInterface{
@@ -975,10 +980,12 @@ func (container *Container) allocateNetwork() error {
 		}
 	}
 
-	portSpecs := make(map[Port]struct{})
+	var (
-	bindings := make(map[Port][]PortBinding)
+		portSpecs = make(map[Port]struct{})
+		bindings  = make(map[Port][]PortBinding)
+	)
 
-	if !container.State.Ghost {
+	if !container.State.IsGhost() {
 		if container.Config.ExposedPorts != nil {
 			portSpecs = container.Config.ExposedPorts
 		}
@@ -1087,7 +1094,7 @@ func (container *Container) monitor() {
 	}
 
 	// Report status back
-	container.State.setStopped(exitCode)
+	container.State.SetStopped(exitCode)
 
 	// Release the lock
 	close(container.waitLock)
@@ -1137,10 +1144,10 @@ func (container *Container) cleanup() {
 }
 
 func (container *Container) kill(sig int) error {
-	container.State.Lock()
+	container.Lock()
-	defer container.State.Unlock()
+	defer container.Unlock()
 
-	if !container.State.Running {
+	if !container.State.IsRunning() {
 		return nil
 	}
 
@@ -1153,7 +1160,7 @@ func (container *Container) kill(sig int) error {
 }
 
 func (container *Container) Kill() error {
-	if !container.State.Running {
+	if !container.State.IsRunning() {
 		return nil
 	}
 
@@ -1178,7 +1185,7 @@ func (container *Container) Kill() error {
 }
 
 func (container *Container) Stop(seconds int) error {
-	if !container.State.Running {
+	if !container.State.IsRunning() {
 		return nil
 	}
 
@@ -1212,7 +1219,7 @@ func (container *Container) Restart(seconds int) error {
 // Wait blocks until the container stops running, then returns its exit code.
 func (container *Container) Wait() int {
 	<-container.waitLock
-	return container.State.ExitCode
+	return container.State.GetExitCode()
 }
 
 func (container *Container) Resize(h, w int) error {

integration/commands_test.go

@@ -289,7 +289,7 @@ func TestRunDisconnect(t *testing.T) {
 	setTimeout(t, "Waiting for /bin/cat to exit timed out", 2*time.Second, func() {
 		container := globalRuntime.List()[0]
 		container.Wait()
-		if container.State.Running {
+		if container.State.IsRunning() {
 			t.Fatalf("/bin/cat is still running after closing stdin")
 		}
 	})
@@ -319,7 +319,7 @@ func TestRunDisconnectTty(t *testing.T) {
 		for {
 			// Client disconnect after run -i should keep stdin out in TTY mode
 			l := globalRuntime.List()
-			if len(l) == 1 && l[0].State.Running {
+			if len(l) == 1 && l[0].State.IsRunning() {
 				break
 			}
 			time.Sleep(10 * time.Millisecond)
@@ -345,7 +345,7 @@ func TestRunDisconnectTty(t *testing.T) {
 
 	// Give some time to monitor to do his thing
 	container.WaitTimeout(500 * time.Millisecond)
-	if !container.State.Running {
+	if !container.State.IsRunning() {
 		t.Fatalf("/bin/cat should  still be running after closing stdin (tty mode)")
 	}
 }
@@ -454,7 +454,7 @@ func TestRunDetach(t *testing.T) {
 	})
 
 	time.Sleep(500 * time.Millisecond)
-	if !container.State.Running {
+	if !container.State.IsRunning() {
 		t.Fatal("The detached container should be still running")
 	}
 
@@ -534,7 +534,7 @@ func TestAttachDetach(t *testing.T) {
 	})
 
 	time.Sleep(500 * time.Millisecond)
-	if !container.State.Running {
+	if !container.State.IsRunning() {
 		t.Fatal("The detached container should be still running")
 	}
 
@@ -596,7 +596,7 @@ func TestAttachDetachTruncatedID(t *testing.T) {
 	})
 
 	time.Sleep(500 * time.Millisecond)
-	if !container.State.Running {
+	if !container.State.IsRunning() {
 		t.Fatal("The detached container should be still running")
 	}
 
@@ -629,7 +629,7 @@ func TestAttachDisconnect(t *testing.T) {
 	setTimeout(t, "Waiting for the container to be started timed out", 10*time.Second, func() {
 		for {
 			l := globalRuntime.List()
-			if len(l) == 1 && l[0].State.Running {
+			if len(l) == 1 && l[0].State.IsRunning() {
 				break
 			}
 			time.Sleep(10 * time.Millisecond)
@@ -665,7 +665,7 @@ func TestAttachDisconnect(t *testing.T) {
 	// We closed stdin, expect /bin/cat to still be running
 	// Wait a little bit to make sure container.monitor() did his thing
 	err := container.WaitTimeout(500 * time.Millisecond)
-	if err == nil || !container.State.Running {
+	if err == nil || !container.State.IsRunning() {
 		t.Fatalf("/bin/cat is not running after closing stdin")
 	}
 

integration/container_test.go

@@ -224,13 +224,13 @@ func TestCommitAutoRun(t *testing.T) {
 	container1, _, _ := mkContainer(runtime, []string{"_", "/bin/sh", "-c", "echo hello > /world"}, t)
 	defer runtime.Destroy(container1)
 
-	if container1.State.Running {
+	if container1.State.IsRunning() {
 		t.Errorf("Container shouldn't be running")
 	}
 	if err := container1.Run(); err != nil {
 		t.Fatal(err)
 	}
-	if container1.State.Running {
+	if container1.State.IsRunning() {
 		t.Errorf("Container shouldn't be running")
 	}
 
@@ -280,13 +280,13 @@ func TestCommitRun(t *testing.T) {
 	container1, _, _ := mkContainer(runtime, []string{"_", "/bin/sh", "-c", "echo hello > /world"}, t)
 	defer runtime.Destroy(container1)
 
-	if container1.State.Running {
+	if container1.State.IsRunning() {
 		t.Errorf("Container shouldn't be running")
 	}
 	if err := container1.Run(); err != nil {
 		t.Fatal(err)
 	}
-	if container1.State.Running {
+	if container1.State.IsRunning() {
 		t.Errorf("Container shouldn't be running")
 	}
 
@@ -352,7 +352,7 @@ func TestStart(t *testing.T) {
 	// Give some time to the process to start
 	container.WaitTimeout(500 * time.Millisecond)
 
-	if !container.State.Running {
+	if !container.State.IsRunning() {
 		t.Errorf("Container should be running")
 	}
 	if err := container.Start(); err == nil {
@@ -370,13 +370,13 @@ func TestRun(t *testing.T) {
 	container, _, _ := mkContainer(runtime, []string{"_", "ls", "-al"}, t)
 	defer runtime.Destroy(container)
 
-	if container.State.Running {
+	if container.State.IsRunning() {
 		t.Errorf("Container shouldn't be running")
 	}
 	if err := container.Run(); err != nil {
 		t.Fatal(err)
 	}
-	if container.State.Running {
+	if container.State.IsRunning() {
 		t.Errorf("Container shouldn't be running")
 	}
 }
@@ -400,7 +400,7 @@ func TestOutput(t *testing.T) {
 		t.Fatal(err)
 	}
 	if string(output) != "foobar" {
-		t.Error(string(output))
+		t.Fatalf("%s != %s", string(output), "foobar")
 	}
 }
 
@@ -421,8 +421,8 @@ func TestContainerNetwork(t *testing.T) {
 	if err := container.Run(); err != nil {
 		t.Fatal(err)
 	}
-	if container.State.ExitCode != 0 {
+	if code := container.State.GetExitCode(); code != 0 {
-		t.Errorf("Unexpected ping 127.0.0.1 exit code %d (expected 0)", container.State.ExitCode)
+		t.Fatalf("Unexpected ping 127.0.0.1 exit code %d (expected 0)", code)
 	}
 }
 
@@ -446,7 +446,7 @@ func TestKillDifferentUser(t *testing.T) {
 	// there is a side effect I'm not seeing.
 	// defer container.stdin.Close()
 
-	if container.State.Running {
+	if container.State.IsRunning() {
 		t.Errorf("Container shouldn't be running")
 	}
 	if err := container.Start(); err != nil {
@@ -454,7 +454,7 @@ func TestKillDifferentUser(t *testing.T) {
 	}
 
 	setTimeout(t, "Waiting for the container to be started timed out", 2*time.Second, func() {
-		for !container.State.Running {
+		for !container.State.IsRunning() {
 			time.Sleep(10 * time.Millisecond)
 		}
 	})
@@ -471,11 +471,11 @@ func TestKillDifferentUser(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	if container.State.Running {
+	if container.State.IsRunning() {
 		t.Errorf("Container shouldn't be running")
 	}
 	container.Wait()
-	if container.State.Running {
+	if container.State.IsRunning() {
 		t.Errorf("Container shouldn't be running")
 	}
 	// Try stopping twice
@@ -533,7 +533,7 @@ func TestKill(t *testing.T) {
 	}
 	defer runtime.Destroy(container)
 
-	if container.State.Running {
+	if container.State.IsRunning() {
 		t.Errorf("Container shouldn't be running")
 	}
 	if err := container.Start(); err != nil {
@@ -543,17 +543,17 @@ func TestKill(t *testing.T) {
 	// Give some time to lxc to spawn the process
 	container.WaitTimeout(500 * time.Millisecond)
 
-	if !container.State.Running {
+	if !container.State.IsRunning() {
 		t.Errorf("Container should be running")
 	}
 	if err := container.Kill(); err != nil {
 		t.Fatal(err)
 	}
-	if container.State.Running {
+	if container.State.IsRunning() {
 		t.Errorf("Container shouldn't be running")
 	}
 	container.Wait()
-	if container.State.Running {
+	if container.State.IsRunning() {
 		t.Errorf("Container shouldn't be running")
 	}
 	// Try stopping twice
@@ -577,8 +577,8 @@ func TestExitCode(t *testing.T) {
 	if err := trueContainer.Run(); err != nil {
 		t.Fatal(err)
 	}
-	if trueContainer.State.ExitCode != 0 {
+	if code := trueContainer.State.GetExitCode(); code != 0 {
-		t.Errorf("Unexpected exit code %d (expected 0)", trueContainer.State.ExitCode)
+		t.Fatalf("Unexpected exit code %d (expected 0)", code)
 	}
 
 	falseContainer, _, err := runtime.Create(&docker.Config{
@@ -592,8 +592,8 @@ func TestExitCode(t *testing.T) {
 	if err := falseContainer.Run(); err != nil {
 		t.Fatal(err)
 	}
-	if falseContainer.State.ExitCode != 1 {
+	if code := falseContainer.State.GetExitCode(); code != 1 {
-		t.Errorf("Unexpected exit code %d (expected 1)", falseContainer.State.ExitCode)
+		t.Fatalf("Unexpected exit code %d (expected 1)", code)
 	}
 }
 
@@ -741,7 +741,7 @@ func TestUser(t *testing.T) {
 	}
 	defer runtime.Destroy(container)
 	output, err = container.Output()
-	if err != nil || container.State.ExitCode != 0 {
+	if code := container.State.GetExitCode(); err != nil || code != 0 {
 		t.Fatal(err)
 	}
 	if !strings.Contains(string(output), "uid=0(root) gid=0(root)") {
@@ -757,12 +757,12 @@ func TestUser(t *testing.T) {
 	},
 		"",
 	)
-	if err != nil || container.State.ExitCode != 0 {
+	if code := container.State.GetExitCode(); err != nil || code != 0 {
 		t.Fatal(err)
 	}
 	defer runtime.Destroy(container)
 	output, err = container.Output()
-	if err != nil || container.State.ExitCode != 0 {
+	if code := container.State.GetExitCode(); err != nil || code != 0 {
 		t.Fatal(err)
 	}
 	if !strings.Contains(string(output), "uid=0(root) gid=0(root)") {
@@ -785,8 +785,8 @@ func TestUser(t *testing.T) {
 	output, err = container.Output()
 	if err != nil {
 		t.Fatal(err)
-	} else if container.State.ExitCode != 0 {
+	} else if code := container.State.GetExitCode(); code != 0 {
-		t.Fatalf("Container exit code is invalid: %d\nOutput:\n%s\n", container.State.ExitCode, output)
+		t.Fatalf("Container exit code is invalid: %d\nOutput:\n%s\n", code, output)
 	}
 	if !strings.Contains(string(output), "uid=1(daemon) gid=1(daemon)") {
 		t.Error(string(output))
@@ -806,7 +806,7 @@ func TestUser(t *testing.T) {
 	}
 	defer runtime.Destroy(container)
 	output, err = container.Output()
-	if err != nil || container.State.ExitCode != 0 {
+	if code := container.State.GetExitCode(); err != nil || code != 0 {
 		t.Fatal(err)
 	}
 	if !strings.Contains(string(output), "uid=1(daemon) gid=1(daemon)") {
@@ -827,7 +827,7 @@ func TestUser(t *testing.T) {
 	}
 	defer runtime.Destroy(container)
 	output, err = container.Output()
-	if container.State.ExitCode == 0 {
+	if container.State.GetExitCode() == 0 {
 		t.Fatal("Starting container with wrong uid should fail but it passed.")
 	}
 }
@@ -871,10 +871,10 @@ func TestMultipleContainers(t *testing.T) {
 	container2.WaitTimeout(250 * time.Millisecond)
 
 	// If we are here, both containers should be running
-	if !container1.State.Running {
+	if !container1.State.IsRunning() {
 		t.Fatal("Container not running")
 	}
-	if !container2.State.Running {
+	if !container2.State.IsRunning() {
 		t.Fatal("Container not running")
 	}
 
@@ -1176,13 +1176,13 @@ func TestCopyVolumeUidGid(t *testing.T) {
 	container1, _, _ := mkContainer(r, []string{"_", "/bin/sh", "-c", "mkdir -p /hello && touch /hello/test.txt && chown daemon.daemon /hello"}, t)
 	defer r.Destroy(container1)
 
-	if container1.State.Running {
+	if container1.State.IsRunning() {
 		t.Errorf("Container shouldn't be running")
 	}
 	if err := container1.Run(); err != nil {
 		t.Fatal(err)
 	}
-	if container1.State.Running {
+	if container1.State.IsRunning() {
 		t.Errorf("Container shouldn't be running")
 	}
 
@@ -1210,13 +1210,13 @@ func TestCopyVolumeContent(t *testing.T) {
 	container1, _, _ := mkContainer(r, []string{"_", "/bin/sh", "-c", "mkdir -p /hello/local && echo hello > /hello/local/world"}, t)
 	defer r.Destroy(container1)
 
-	if container1.State.Running {
+	if container1.State.IsRunning() {
 		t.Errorf("Container shouldn't be running")
 	}
 	if err := container1.Run(); err != nil {
 		t.Fatal(err)
 	}
-	if container1.State.Running {
+	if container1.State.IsRunning() {
 		t.Errorf("Container shouldn't be running")
 	}
 
@@ -1666,17 +1666,17 @@ func TestRestartGhost(t *testing.T) {
 		},
 		"",
 	)
-
 	if err != nil {
 		t.Fatal(err)
 	}
+
 	if err := container.Kill(); err != nil {
 		t.Fatal(err)
 	}
 
-	container.State.Ghost = true
+	container.State.SetGhost(true)
-	_, err = container.Output()
 
+	_, err = container.Output()
 	if err != nil {
 		t.Fatal(err)
 	}

integration/runtime_test.go

@@ -419,7 +419,7 @@ func startEchoServerContainer(t *testing.T, proto string) (*docker.Runtime, *doc
 	}
 
 	setTimeout(t, "Waiting for the container to be started timed out", 2*time.Second, func() {
-		for !container.State.Running {
+		for !container.State.IsRunning() {
 			time.Sleep(10 * time.Millisecond)
 		}
 	})
@@ -533,7 +533,7 @@ func TestRestore(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	if !container2.State.Running {
+	if !container2.State.IsRunning() {
 		t.Fatalf("Container %v should appear as running but isn't", container2.ID)
 	}
 
@@ -543,7 +543,7 @@ func TestRestore(t *testing.T) {
 	if err := container2.WaitTimeout(2 * time.Second); err != nil {
 		t.Fatal(err)
 	}
-	container2.State.Running = true
+	container2.State.SetRunning(42)
 	container2.ToDisk()
 
 	if len(runtime1.List()) != 2 {
@@ -553,7 +553,7 @@ func TestRestore(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	if !container2.State.Running {
+	if !container2.State.IsRunning() {
 		t.Fatalf("Container %v should appear as running but isn't", container2.ID)
 	}
 
@@ -577,7 +577,7 @@ func TestRestore(t *testing.T) {
 	}
 	runningCount := 0
 	for _, c := range runtime2.List() {
-		if c.State.Running {
+		if c.State.IsRunning() {
 			t.Errorf("Running container found: %v (%v)", c.ID, c.Path)
 			runningCount++
 		}
@@ -592,7 +592,7 @@ func TestRestore(t *testing.T) {
 	if err := container3.Run(); err != nil {
 		t.Fatal(err)
 	}
-	container2.State.Running = false
+	container2.State.SetStopped(0)
 }
 
 func TestReloadContainerLinks(t *testing.T) {
@@ -638,11 +638,11 @@ func TestReloadContainerLinks(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	if !container2.State.Running {
+	if !container2.State.IsRunning() {
 		t.Fatalf("Container %v should appear as running but isn't", container2.ID)
 	}
 
-	if !container1.State.Running {
+	if !container1.State.IsRunning() {
 		t.Fatalf("Container %s should appear as running but isn't", container1.ID)
 	}
 
@@ -669,7 +669,7 @@ func TestReloadContainerLinks(t *testing.T) {
 	}
 	runningCount := 0
 	for _, c := range runtime2.List() {
-		if c.State.Running {
+		if c.State.IsRunning() {
 			runningCount++
 		}
 	}

integration/utils_test.go

@@ -111,7 +111,7 @@ func containerKill(eng *engine.Engine, id string, t utils.Fataler) {
 }
 
 func containerRunning(eng *engine.Engine, id string, t utils.Fataler) bool {
-	return getContainer(eng, id, t).State.Running
+	return getContainer(eng, id, t).State.IsRunning()
 }
 
 func containerAssertExists(eng *engine.Engine, id string, t utils.Fataler) {

links.go

@@ -21,7 +21,7 @@ func NewLink(parent, child *Container, name, bridgeInterface string) (*Link, err
 	if parent.ID == child.ID {
 		return nil, fmt.Errorf("Cannot link to self: %s == %s", parent.ID, child.ID)
 	}
-	if !child.State.Running {
+	if !child.State.IsRunning() {
 		return nil, fmt.Errorf("Cannot link to a non running container: %s AS %s", child.Name, name)
 	}
 

runtime.go

@@ -100,8 +100,8 @@ func (runtime *Runtime) load(id string) (*Container, error) {
 	if container.ID != id {
 		return container, fmt.Errorf("Container %s is stored at %s", container.ID, id)
 	}
-	if container.State.Running {
+	if container.State.IsRunning() {
-		container.State.Ghost = true
+		container.State.SetGhost(true)
 	}
 	return container, nil
 }
@@ -136,7 +136,7 @@ func (runtime *Runtime) Register(container *Container) error {
 	// FIXME: if the container is supposed to be running but is not, auto restart it?
 	//        if so, then we need to restart monitor and init a new lock
 	// If the container is supposed to be running, make sure of it
-	if container.State.Running {
+	if container.State.IsRunning() {
 		output, err := exec.Command("lxc-info", "-n", container.ID).CombinedOutput()
 		if err != nil {
 			return err
@@ -145,14 +145,14 @@ func (runtime *Runtime) Register(container *Container) error {
 			utils.Debugf("Container %s was supposed to be running be is not.", container.ID)
 			if runtime.config.AutoRestart {
 				utils.Debugf("Restarting")
-				container.State.Ghost = false
+				container.State.SetGhost(false)
-				container.State.setStopped(0)
+				container.State.SetStopped(0)
 				if err := container.Start(); err != nil {
 					return err
 				}
 			} else {
 				utils.Debugf("Marking as stopped")
-				container.State.setStopped(-127)
+				container.State.SetStopped(-127)
 				if err := container.ToDisk(); err != nil {
 					return err
 				}

server.go

@@ -694,7 +694,7 @@ func (srv *Server) Containers(all, size bool, n int, since, before string) []API
 	}, -1)
 
 	for _, container := range srv.runtime.List() {
-		if !container.State.Running && !all && n == -1 && since == "" && before == "" {
+		if !container.State.IsRunning() && !all && n == -1 && since == "" && before == "" {
 			continue
 		}
 		if before != "" && !foundBefore {
@@ -1339,7 +1339,7 @@ func (srv *Server) ContainerDestroy(name string, removeVolume, removeLink bool)
 	}
 
 	if container != nil {
-		if container.State.Running {
+		if container.State.IsRunning() {
 			return fmt.Errorf("Impossible to remove a running container, please stop it first")
 		}
 		volumes := make(map[string]struct{})
@@ -1516,7 +1516,7 @@ func (srv *Server) ImageDelete(name string, autoPrune bool) ([]APIRmi, error) {
 
 	// Prevent deletion if image is used by a running container
 	for _, container := range srv.runtime.List() {
-		if container.State.Running {
+		if container.State.IsRunning() {
 			parent, err := srv.runtime.repositories.LookupImage(container.Image)
 			if err != nil {
 				return nil, err
@@ -1738,7 +1738,7 @@ func (srv *Server) ContainerAttach(name string, logs, stream, stdin, stdout, std
 
 	//stream
 	if stream {
-		if container.State.Ghost {
+		if container.State.IsGhost() {
 			return fmt.Errorf("Impossible to attach to a ghost container")
 		}
 

state.go

@@ -8,7 +8,7 @@ import (
 )
 
 type State struct {
-	sync.Mutex
+	sync.RWMutex
 	Running    bool
 	Pid        int
 	ExitCode   int
@@ -19,6 +19,9 @@ type State struct {
 
 // String returns a human-readable description of the state
 func (s *State) String() string {
+	s.RLock()
+	defer s.RUnlock()
+
 	if s.Running {
 		if s.Ghost {
 			return fmt.Sprintf("Ghost")
@@ -28,7 +31,38 @@ func (s *State) String() string {
 	return fmt.Sprintf("Exit %d", s.ExitCode)
 }
 
-func (s *State) setRunning(pid int) {
+func (s *State) IsRunning() bool {
+	s.RLock()
+	defer s.RUnlock()
+
+	return s.Running
+}
+
+func (s *State) IsGhost() bool {
+	s.RLock()
+	defer s.RUnlock()
+
+	return s.Ghost
+}
+
+func (s *State) GetExitCode() int {
+	s.RLock()
+	defer s.RUnlock()
+
+	return s.ExitCode
+}
+
+func (s *State) SetGhost(val bool) {
+	s.Lock()
+	defer s.Unlock()
+
+	s.Ghost = val
+}
+
+func (s *State) SetRunning(pid int) {
+	s.Lock()
+	defer s.Unlock()
+
 	s.Running = true
 	s.Ghost = false
 	s.ExitCode = 0
@@ -36,7 +70,10 @@ func (s *State) setRunning(pid int) {
 	s.StartedAt = time.Now()
 }
 
-func (s *State) setStopped(exitCode int) {
+func (s *State) SetStopped(exitCode int) {
+	s.Lock()
+	defer s.Unlock()
+
 	s.Running = false
 	s.Pid = 0
 	s.FinishedAt = time.Now()