bugfix: avoid data race in set exec exit status

there are two goroutines response for changed exec config information,
if exec process got error, data race appears, exec exit hook runs in a
goroutine, it modify exec exit status, StartExec also modify exec exit
status in another goroutine since error happend. Fix it by only one
place can modify exec exit status.

Signed-off-by: Ace-Tang <aceapril@126.com>

ctrd/container.go

@@ -122,14 +122,13 @@ func (c *Client) execContainer(ctx context.Context, process *Process) error {
 			exitTime: status.ExitTime(),
 		}
 
-		if err := <-fail; err != nil {
-			msg.err = err
-		}
-
-		for _, hook := range c.hooks {
-			if err := hook(process.ExecID, msg); err != nil {
-				logrus.Errorf("failed to execute the exec exit hooks: %v", err)
-				break
+		// run hook if not got fail here
+		if err := <-fail; err == nil {
+			for _, hook := range c.hooks {
+				if err := hook(process.ExecID, msg); err != nil {
+					logrus.Errorf("failed to execute the exec exit hooks: %v", err)
+					break
+				}
 			}
 		}
 

daemon/mgr/container_exec.go

@@ -77,7 +77,6 @@ func (mgr *ContainerManager) StartExec(ctx context.Context, execid string, attac
 			exitCode := 126
 			execConfig.ExitCode = int64(exitCode)
 		}
-		mgr.ExecProcesses.Put(execid, execConfig)
 	}()
 
 	if attach != nil {

test/cli_exec_test.go

@@ -144,12 +144,23 @@ func (suite *PouchExecSuite) TestExecExitCode(c *check.C) {
 	command.PouchRun("exec", name, "sh", "-c", "exit 0").Assert(c, icmd.Success)
 }
 
-// TestExecFail test exec fail should not hang.
+// TestExecFail test exec fail should not hang, and test failed exec exit code should not be zero.
 func (suite *PouchExecSuite) TestExecFail(c *check.C) {
 	name := "TestExecFail"
 	res := command.PouchRun("run", "-d", "--name", name, "-u", name, busyboxImage, "top")
 	defer DelContainerForceMultyTime(c, name)
 	c.Assert(res.Stderr(), check.NotNil)
+
+	// test a 'executable file not found' fail should get exit code 126.
+	name = "TestExecFailCode"
+	command.PouchRun("run", "-d", "--name", name, busyboxImage, "top").Assert(c, icmd.Success)
+	command.PouchRun("exec", name, "shouldnotexit").Assert(c, icmd.Expected{ExitCode: 126})
+
+	// test a 'ls /nosuchfile' fail should get exit code not equal to 0.
+	res = command.PouchRun("exec", name, "ls", "/nosuchfile")
+	if res.ExitCode == 0 {
+		c.Fatalf("failed exec process exit code should not be 0")
+	}
 }
 
 // TestExecUser test exec with user.