virtcontainers: Properly end up go routines using channels

Those different files were all calling into a go routine that was
eventually reporting some result through a go channel. The problem
was the way those routine were implemented, as they were hanging
around forever. Indeed, nothing was actually listening to the channel
in some cases, and those routines never ended.

This was one of the problem detected by the fact that our unit tests
needed more time to pass because when they were all run in parallel,
the resources consumed by those routines were increasing the time
for other tests to complete.

Fixes #208

Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>

virtcontainers/cc_shim_test.go

@@ -242,8 +242,9 @@ func TestCCShimStartDetachSuccessful(t *testing.T) {
 
 	testCCShimStart(t, sandbox, params, false)
 
-	readCh := make(chan error)
+	readCh := make(chan error, 1)
 	go func() {
+		defer close(readCh)
 		bufStdout := make([]byte, 1024)
 		n, err := rStdout.Read(bufStdout)
 		if err != nil && err != io.EOF {

virtcontainers/hook.go

@@ -22,6 +22,7 @@ import (
 	"fmt"
 	"os"
 	"os/exec"
+	"syscall"
 	"time"
 
 	specs "github.com/opencontainers/runtime-spec/specs-go"
@@ -82,9 +83,11 @@ func (h *Hook) runHook() error {
 			return fmt.Errorf("%s: stdout: %s, stderr: %s", err, stdout.String(), stderr.String())
 		}
 	} else {
-		done := make(chan error)
-
-		go func() { done <- cmd.Wait() }()
+		done := make(chan error, 1)
+		go func() {
+			done <- cmd.Wait()
+			close(done)
+		}()
 
 		select {
 		case err := <-done:
@@ -92,6 +95,10 @@ func (h *Hook) runHook() error {
 				return fmt.Errorf("%s: stdout: %s, stderr: %s", err, stdout.String(), stderr.String())
 			}
 		case <-time.After(time.Duration(h.Timeout) * time.Second):
+			if err := syscall.Kill(cmd.Process.Pid, syscall.SIGKILL); err != nil {
+				return err
+			}
+
 			return fmt.Errorf("Hook timeout")
 		}
 	}

virtcontainers/kata_shim_test.go

@@ -236,8 +236,9 @@ func TestKataShimStartDetachSuccessful(t *testing.T) {
 
 	testKataShimStart(t, sandbox, params, false)
 
-	readCh := make(chan error)
+	readCh := make(chan error, 1)
 	go func() {
+		defer close(readCh)
 		bufStdout := make([]byte, 1024)
 		n, err := rStdout.Read(bufStdout)
 		if err != nil && err != io.EOF {