Initial commit of libcontainer

Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)

libcontainer/utils/utils.go

@@ -0,0 +1,33 @@
+package utils
+
+import (
+	"crypto/rand"
+	"encoding/hex"
+	"io"
+	"os"
+	"syscall"
+)
+
+func WaitOnPid(pid int) (exitcode int, err error) {
+	child, err := os.FindProcess(pid)
+	if err != nil {
+		return -1, err
+	}
+	state, err := child.Wait()
+	if err != nil {
+		return -1, err
+	}
+	return getExitCode(state), nil
+}
+
+func getExitCode(state *os.ProcessState) int {
+	return state.Sys().(syscall.WaitStatus).ExitStatus()
+}
+
+func GenerateRandomName(size int) (string, error) {
+	id := make([]byte, size)
+	if _, err := io.ReadFull(rand.Reader, id); err != nil {
+		return "", err
+	}
+	return hex.EncodeToString(id), nil
+}