Add container start and supervisor

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

execution/container.go

@@ -1,14 +1,64 @@
 package execution
 
+import "fmt"
+
+func NewContainer(stateRoot, id, bundle string) (*Container, error) {
+	stateDir, err := NewStateDir(stateRoot, id)
+	if err != nil {
+		return nil, err
+	}
+	return &Container{
+		id:        id,
+		bundle:    bundle,
+		stateDir:  stateDir,
+		processes: make(map[string]Process),
+	}, nil
+}
+
+func LoadContainer(dir StateDir, id, bundle string, initPid int) *Container {
+	return &Container{
+		id:        id,
+		stateDir:  dir,
+		bundle:    bundle,
+		initPid:   initPid,
+		processes: make(map[string]Process),
+	}
+}
+
 type Container struct {
-	ID       string
-	Bundle   string
-	StateDir StateDir
+	id       string
+	bundle   string
+	stateDir StateDir
+	initPid  int
 
 	processes map[string]Process
 }
 
-func (c *Container) AddProcess(p Process) {
+func (c *Container) ID() string {
+	return c.id
+}
+
+func (c *Container) Bundle() string {
+	return c.bundle
+}
+
+func (c *Container) StateDir() StateDir {
+	return c.stateDir
+}
+
+func (c *Container) Wait() (uint32, error) {
+	for _, p := range c.processes {
+		if p.Pid() == c.initPid {
+			return p.Wait()
+		}
+	}
+	return nil, fmt.Errorf("no init process")
+}
+
+func (c *Container) AddProcess(p Process, isInit bool) {
+	if isInit {
+		c.initPid = p.Pid()
+	}
 	c.processes[p.ID()] = p
 }