win-sshproxy.tid created before thread id is available

this commit fixes a potential race condition that prevented the tests to succeed
when running in a github workflow.
Basically the thread id was not actually available before
writing it on the file, resulting in a thread id equals to 0 written in it.
So, when the tests were trying to retrieve the thread id to use it to send
the WM_QUIT signal, they failed.

This patch adds a check on the thread id before writing
it on the file. Now, if the thread id is 0, it keeps calling winquit to
retrieve it. If, after 10 secs, there is no success it returns an error.

Signed-off-by: lstocchi <[email protected]>

cmd/win-sshproxy/main.go

@@ -11,6 +11,7 @@ import (
 	"path/filepath"
 	"strings"
 	"syscall"
+	"time"
 	"unsafe"
 
 	"github.com/containers/gvisor-tap-vsock/pkg/sshclient"
@@ -173,11 +174,35 @@ func saveThreadId() (uint32, error) {
 		return 0, err
 	}
 	defer file.Close()
-	tid := winquit.GetCurrentMessageLoopThreadId()
+
+	tid, err := getThreadId()
+	if err != nil {
+		return 0, err
+	}
+
 	fmt.Fprintf(file, "%d:%d\n", os.Getpid(), tid)
 	return tid, nil
 }
 
+func getThreadId() (uint32, error) {
+	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer cancel()
+
+	var tid uint32
+	for {
+		select {
+		case <-ctx.Done():
+			return 0, fmt.Errorf("failed to get thread ID")
+		default:
+			tid = winquit.GetCurrentMessageLoopThreadId()
+			if tid != 0 {
+				return tid, nil
+			}
+			time.Sleep(100 * time.Millisecond)
+		}
+	}
+}
+
 // Creates an "error" style pop-up window
 func alert(caption string) int {
 	// Error box style

test-win-sshproxy/basic_test.go

@@ -1,3 +1,4 @@
+//go:build windows
 // +build windows
 
 package e2e
@@ -25,15 +26,16 @@ var _ = Describe("connectivity", func() {
 		err := startProxy()
 		Expect(err).ShouldNot(HaveOccurred())
 
-		var pid uint32
+		var pid, tid uint32
 		for i := 0; i < 20; i++ {
-			pid, _, err = readTid()
-			if err == nil {
+			pid, tid, err = readTid()
+			if err == nil && tid != 0 {
 				break
 			}
 			time.Sleep(100 * time.Millisecond)
 		}
 
+		Expect(tid).ShouldNot(Equal(0))
 		Expect(err).ShouldNot(HaveOccurred())
 		proc, err := os.FindProcess(int(pid))
 		Expect(err).ShouldNot(HaveOccurred())