Add ensureState helper for checking container state

We have a lot of checks for container state scattered throughout
libpod. Many of these need to ensure the container is in one of a
given set of states so an operation may safely proceed.
Previously there was no set way of doing this, so we'd use unique
boolean logic for each one. Introduce a helper to standardize
state checks.

Note that this is only intended to replace checks for multiple
states. A simple check for one state (ContainerStateRunning, for
example) should remain a straight equality, and not use this new
helper.

Signed-off-by: Matthew Heon <mheon@redhat.com>

3 files changed, 46 insertions, 52 deletions

diff --git a/libpod/container.go b/libpod/container.go
index 7be73b3c3..fc9ef0c86 100644
--- a/libpod/container.go
+++ b/libpod/container.go
@@ -1185,3 +1185,12 @@ func (c *Container) HasHealthCheck() bool {
 func (c *Container) HealthCheckConfig() *manifest.Schema2HealthConfig {
 	return c.config.HealthCheckConfig
 }
+
+// AutoRemove indicates whether the container will be removed after it is executed
+func (c *Container) AutoRemove() bool {
+	spec := c.config.Spec
+	if spec.Annotations == nil {
+		return false
+	}
+	return c.Spec().Annotations[InspectAnnotationAutoremove] == InspectResponseTrue
+}
diff --git a/libpod/container_api.go b/libpod/container_api.go
index 759a7067e..1b2d52ce3 100644
--- a/libpod/container_api.go
+++ b/libpod/container_api.go
@@ -32,9 +32,7 @@ func (c *Container) Init(ctx context.Context) (err error) {
 		}
 	}
 
-	if !(c.state.State == define.ContainerStateConfigured ||
-		c.state.State == define.ContainerStateStopped ||
-		c.state.State == define.ContainerStateExited) {
+	if !c.ensureState(define.ContainerStateConfigured, define.ContainerStateStopped, define.ContainerStateExited) {
 		return errors.Wrapf(define.ErrCtrStateInvalid, "container %s has already been created in runtime", c.ID())
 	}
 
@@ -176,15 +174,12 @@ func (c *Container) StopWithTimeout(timeout uint) error {
 		}
 	}
 
-	if c.state.State == define.ContainerStateConfigured ||
-		c.state.State == define.ContainerStateUnknown ||
-		c.state.State == define.ContainerStatePaused {
-		return errors.Wrapf(define.ErrCtrStateInvalid, "can only stop created, running, or stopped containers. %s is in state %s", c.ID(), c.state.State.String())
+	if c.ensureState(define.ContainerStateStopped, define.ContainerStateExited) {
+		return define.ErrCtrStopped
 	}
 
-	if c.state.State == define.ContainerStateStopped ||
-		c.state.State == define.ContainerStateExited {
-		return define.ErrCtrStopped
+	if !c.ensureState(define.ContainerStateCreated, define.ContainerStateRunning) {
+		return errors.Wrapf(define.ErrCtrStateInvalid, "can only stop created or running containers. %s is in state %s", c.ID(), c.state.State.String())
 	}
 
 	return c.stop(timeout, false)
@@ -201,6 +196,7 @@ func (c *Container) Kill(signal uint) error {
 		}
 	}
 
+	// TODO: Is killing a paused container OK?
 	if c.state.State != define.ContainerStateRunning {
 		return errors.Wrapf(define.ErrCtrStateInvalid, "can only kill running containers. %s is in state %s", c.ID(), c.state.State.String())
 	}
@@ -234,10 +230,7 @@ func (c *Container) Exec(tty, privileged bool, env map[string]string, cmd []stri
 		}
 	}
 
-	conState := c.state.State
-
-	// TODO can probably relax this once we track exec sessions
-	if conState != define.ContainerStateRunning {
+	if c.state.State != define.ContainerStateRunning {
 		return define.ExecErrorCodeCannotInvoke, errors.Wrapf(define.ErrCtrStateInvalid, "cannot exec into container that is not running")
 	}
 
@@ -391,11 +384,10 @@ func (c *Container) Attach(streams *AttachStreams, keys string, resize <-chan re
 		c.lock.Unlock()
 	}
 
-	if c.state.State != define.ContainerStateCreated &&
-		c.state.State != define.ContainerStateRunning &&
-		c.state.State != define.ContainerStateExited {
+	if !c.ensureState(define.ContainerStateCreated, define.ContainerStateRunning) {
 		return errors.Wrapf(define.ErrCtrStateInvalid, "can only attach to created or running containers")
 	}
+
 	defer c.newContainerEvent(events.Attach)
 	return c.attach(streams, keys, resize, false, nil)
 }
@@ -432,7 +424,7 @@ func (c *Container) Unmount(force bool) error {
 			return errors.Wrapf(err, "can't determine how many times %s is mounted, refusing to unmount", c.ID())
 		}
 		if mounted == 1 {
-			if c.state.State == define.ContainerStateRunning || c.state.State == define.ContainerStatePaused {
+			if c.ensureState(define.ContainerStateRunning, define.ContainerStatePaused) {
 				return errors.Wrapf(define.ErrCtrStateInvalid, "cannot unmount storage for container %s as it is running or paused", c.ID())
 			}
 			if len(c.state.ExecSessions) != 0 {
@@ -574,7 +566,7 @@ func (c *Container) Cleanup(ctx context.Context) error {
 	}
 
 	// Check if state is good
-	if c.state.State == define.ContainerStateRunning || c.state.State == define.ContainerStatePaused {
+	if !c.ensureState(define.ContainerStateConfigured, define.ContainerStateCreated, define.ContainerStateStopped, define.ContainerStateExited) {
 		return errors.Wrapf(define.ErrCtrStateInvalid, "container %s is running or paused, refusing to clean up", c.ID())
 	}
 
@@ -652,9 +644,7 @@ func (c *Container) Sync() error {
 
 	// If runtime knows about the container, update its status in runtime
 	// And then save back to disk
-	if (c.state.State != define.ContainerStateUnknown) &&
-		(c.state.State != define.ContainerStateConfigured) &&
-		(c.state.State != define.ContainerStateExited) {
+	if c.ensureState(define.ContainerStateCreated, define.ContainerStateRunning, define.ContainerStatePaused, define.ContainerStateStopped) {
 		oldState := c.state.State
 		if err := c.ociRuntime.UpdateContainerStatus(c); err != nil {
 			return err
@@ -666,6 +656,7 @@ func (c *Container) Sync() error {
 			}
 		}
 	}
+
 	defer c.newContainerEvent(events.Sync)
 	return nil
 }
@@ -840,12 +831,3 @@ func (c *Container) Restore(ctx context.Context, options ContainerCheckpointOpti
 	defer c.newContainerEvent(events.Restore)
 	return c.restore(ctx, options)
 }
-
-// AutoRemove indicates whether the container will be removed after it is executed
-func (c *Container) AutoRemove() bool {
-	spec := c.config.Spec
-	if spec.Annotations == nil {
-		return false
-	}
-	return c.Spec().Annotations[InspectAnnotationAutoremove] == InspectResponseTrue
-}
diff --git a/libpod/container_internal.go b/libpod/container_internal.go
index 0043c9651..028d7601d 100644
--- a/libpod/container_internal.go
+++ b/libpod/container_internal.go
@@ -328,7 +328,7 @@ func (c *Container) handleRestartPolicy(ctx context.Context) (restarted bool, er
 
 	// Is the container running again?
 	// If so, we don't have to do anything
-	if c.state.State == define.ContainerStateRunning || c.state.State == define.ContainerStatePaused {
+	if c.ensureState(define.ContainerStateRunning, define.ContainerStatePaused) {
 		return false, nil
 	} else if c.state.State == define.ContainerStateUnknown {
 		return false, errors.Wrapf(define.ErrInternal, "invalid container state encountered in restart attempt!")
@@ -359,8 +359,7 @@ func (c *Container) handleRestartPolicy(ctx context.Context) (restarted bool, er
 		if err := c.reinit(ctx, true); err != nil {
 			return false, err
 		}
-	} else if c.state.State == define.ContainerStateConfigured ||
-		c.state.State == define.ContainerStateExited {
+	} else if c.ensureState(define.ContainerStateConfigured, define.ContainerStateExited) {
 		// Initialize the container
 		if err := c.init(ctx, true); err != nil {
 			return false, err
@@ -372,6 +371,18 @@ func (c *Container) handleRestartPolicy(ctx context.Context) (restarted bool, er
 	return true, nil
 }
 
+// Ensure that the container is in a specific state or state.
+// Returns true if the container is in one of the given states,
+// or false otherwise.
+func (c *Container) ensureState(states ...define.ContainerStatus) bool {
+	for _, state := range states {
+		if state == c.state.State {
+			return true
+		}
+	}
+	return false
+}
+
 // Sync this container with on-disk state and runtime status
 // Should only be called with container lock held
 // This function should suffice to ensure a container's state is accurate and
@@ -382,9 +393,7 @@ func (c *Container) syncContainer() error {
 	}
 	// If runtime knows about the container, update its status in runtime
 	// And then save back to disk
-	if (c.state.State != define.ContainerStateUnknown) &&
-		(c.state.State != define.ContainerStateConfigured) &&
-		(c.state.State != define.ContainerStateExited) {
+	if c.ensureState(define.ContainerStateCreated, define.ContainerStateRunning, define.ContainerStateStopped, define.ContainerStatePaused) {
 		oldState := c.state.State
 
 		if err := c.checkExitFile(); err != nil {
@@ -516,7 +525,7 @@ func (c *Container) setupStorage(ctx context.Context) error {
 
 // Tear down a container's storage prior to removal
 func (c *Container) teardownStorage() error {
-	if c.state.State == define.ContainerStateRunning || c.state.State == define.ContainerStatePaused {
+	if c.ensureState(define.ContainerStateRunning, define.ContainerStatePaused) {
 		return errors.Wrapf(define.ErrCtrStateInvalid, "cannot remove storage for container %s as it is running or paused", c.ID())
 	}
 
@@ -721,10 +730,7 @@ func (c *Container) save() error {
 // Otherwise, this function will return with error if there are dependencies of this container that aren't running.
 func (c *Container) prepareToStart(ctx context.Context, recursive bool) (err error) {
 	// Container must be created or stopped to be started
-	if !(c.state.State == define.ContainerStateConfigured ||
-		c.state.State == define.ContainerStateCreated ||
-		c.state.State == define.ContainerStateStopped ||
-		c.state.State == define.ContainerStateExited) {
+	if !c.ensureState(define.ContainerStateConfigured, define.ContainerStateCreated, define.ContainerStateStopped, define.ContainerStateExited) {
 		return errors.Wrapf(define.ErrCtrStateInvalid, "container %s must be in Created or Stopped state to be started", c.ID())
 	}
 
@@ -755,8 +761,7 @@ func (c *Container) prepareToStart(ctx context.Context, recursive bool) (err err
 		if err := c.reinit(ctx, false); err != nil {
 			return err
 		}
-	} else if c.state.State == define.ContainerStateConfigured ||
-		c.state.State == define.ContainerStateExited {
+	} else if c.ensureState(define.ContainerStateConfigured, define.ContainerStateExited) {
 		// Or initialize it if necessary
 		if err := c.init(ctx, false); err != nil {
 			return err
@@ -987,7 +992,7 @@ func (c *Container) cleanupRuntime(ctx context.Context) error {
 
 	// If the container is not ContainerStateStopped or
 	// ContainerStateCreated, do nothing.
-	if c.state.State != define.ContainerStateStopped && c.state.State != define.ContainerStateCreated {
+	if !c.ensureState(define.ContainerStateStopped, define.ContainerStateCreated) {
 		return nil
 	}
 
@@ -1078,8 +1083,7 @@ func (c *Container) initAndStart(ctx context.Context) (err error) {
 		if err := c.reinit(ctx, false); err != nil {
 			return err
 		}
-	} else if c.state.State == define.ContainerStateConfigured ||
-		c.state.State == define.ContainerStateExited {
+	} else if c.ensureState(define.ContainerStateConfigured, define.ContainerStateExited) {
 		if err := c.init(ctx, false); err != nil {
 			return err
 		}
@@ -1205,7 +1209,7 @@ func (c *Container) unpause() error {
 
 // Internal, non-locking function to restart a container
 func (c *Container) restartWithTimeout(ctx context.Context, timeout uint) (err error) {
-	if c.state.State == define.ContainerStateUnknown || c.state.State == define.ContainerStatePaused {
+	if !c.ensureState(define.ContainerStateConfigured, define.ContainerStateCreated, define.ContainerStateRunning, define.ContainerStateStopped, define.ContainerStateExited) {
 		return errors.Wrapf(define.ErrCtrStateInvalid, "unable to restart a container in a paused or unknown state")
 	}
 
@@ -1733,9 +1737,8 @@ func (c *Container) checkReadyForRemoval() error {
 		return errors.Wrapf(define.ErrCtrStateInvalid, "container %s is in invalid state", c.ID())
 	}
 
-	if c.state.State == define.ContainerStateRunning ||
-		c.state.State == define.ContainerStatePaused {
-		return errors.Wrapf(define.ErrCtrStateInvalid, "cannot remove container %s as it is %s - running or paused containers cannot be removed", c.ID(), c.state.State.String())
+	if c.ensureState(define.ContainerStateRunning, define.ContainerStatePaused) {
+		return errors.Wrapf(define.ErrCtrStateInvalid, "cannot remove container %s as it is %s - running or paused containers cannot be removed without force", c.ID(), c.state.State.String())
 	}
 
 	if len(c.state.ExecSessions) != 0 {
@@ -1816,7 +1819,7 @@ func (c *Container) sortUserVolumes(ctrSpec *spec.Spec) ([]*ContainerNamedVolume
 // Check for an exit file, and handle one if present
 func (c *Container) checkExitFile() error {
 	// If the container's not running, nothing to do.
-	if c.state.State != define.ContainerStateRunning && c.state.State != define.ContainerStatePaused {
+	if !c.ensureState(define.ContainerStateRunning, define.ContainerStatePaused) {
 		return nil
 	}