Record whether the container has exited

Use this to supplement exit codes returned from containers, to
make sure we know when exit codes are invalid (as the container
has not yet exited)

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

libpod/container.go

@@ -135,6 +135,8 @@ type containerState struct {
 	FinishedTime time.Time `json:"finishedTime,omitempty"`
 	// ExitCode is the exit code returned when the container stopped
 	ExitCode int32 `json:"exitCode,omitempty"`
+	// Exited is whether the container has exited
+	Exited bool `json:"exited,omitempty"`
 	// OOMKilled indicates that the container was killed as it ran out of
 	// memory
 	OOMKilled bool `json:"oomKilled,omitempty"`
@@ -667,16 +669,18 @@ func (c *Container) FinishedTime() (time.Time, error) {
 }
 
 // ExitCode returns the exit code of the container as
-// an int32
-func (c *Container) ExitCode() (int32, error) {
+// an int32, and whether the container has exited.
+// If the container has not exited, exit code will always be 0.
+// If the container restarts, the exit code is reset to 0.
+func (c *Container) ExitCode() (int32, bool, error) {
 	if !c.batched {
 		c.lock.Lock()
 		defer c.lock.Unlock()
 		if err := c.syncContainer(); err != nil {
-			return 0, errors.Wrapf(err, "error updating container %s state", c.ID())
+			return 0, false, errors.Wrapf(err, "error updating container %s state", c.ID())
 		}
 	}
-	return c.state.ExitCode, nil
+	return c.state.ExitCode, c.state.Exited, nil
 }
 
 // OOMKilled returns whether the container was killed by an OOM condition