container: forward context cancellation

This allows container processes to exit gracefully.

Signed-off-by: Ophestra <cat@gensokyo.uk>

container/container_test.go

@@ -8,6 +8,8 @@ import (
 	"fmt"
 	"log"
 	"os"
+	"os/exec"
+	"os/signal"
 	"strconv"
 	"strings"
 	"syscall"
@@ -90,41 +92,32 @@ func TestContainer(t *testing.T) {
 		t.Cleanup(func() { container.SetOutput(oldOutput) })
 	}
 
-	t.Run("cancel", func(t *testing.T) {
-		ctx, cancel := context.WithTimeout(t.Context(), helperDefaultTimeout)
-
-		c := helperNewContainer(ctx, "block")
-		c.Stdout, c.Stderr = os.Stdout, os.Stderr
-		c.WaitDelay = helperDefaultTimeout
-
-		ready := make(chan struct{})
-		if r, w, err := os.Pipe(); err != nil {
-			t.Fatalf("cannot pipe: %v", err)
-		} else {
-			c.ExtraFiles = append(c.ExtraFiles, w)
-			go func() {
-				defer close(ready)
-				if _, err = r.Read(make([]byte, 1)); err != nil {
-					panic(err.Error())
-				}
-			}()
-		}
-
-		if err := c.Start(); err != nil {
-			hlog.PrintBaseError(err, "start:")
-			t.Fatalf("cannot start container: %v", err)
-		} else if err = c.Serve(); err != nil {
-			hlog.PrintBaseError(err, "serve:")
-			t.Errorf("cannot serve setup params: %v", err)
-		}
-		<-ready
-		cancel()
+	t.Run("cancel", testContainerCancel(nil, func(t *testing.T, c *container.Container) {
 		wantErr := context.Canceled
+		wantExitCode := 0
 		if err := c.Wait(); !errors.Is(err, wantErr) {
 			hlog.PrintBaseError(err, "wait:")
-			t.Fatalf("Wait: error = %v, want %v", err, wantErr)
+			t.Errorf("Wait: error = %v, want %v", err, wantErr)
 		}
-	})
+		if ps := c.ProcessState(); ps == nil {
+			t.Errorf("ProcessState unexpectedly returned nil")
+		} else if code := ps.ExitCode(); code != wantExitCode {
+			t.Errorf("ExitCode: %d, want %d", code, wantExitCode)
+		}
+	}))
+
+	t.Run("forward", testContainerCancel(func(c *container.Container) {
+		c.ForwardCancel = true
+	}, func(t *testing.T, c *container.Container) {
+		var exitError *exec.ExitError
+		if err := c.Wait(); !errors.As(err, &exitError) {
+			hlog.PrintBaseError(err, "wait:")
+			t.Errorf("Wait: error = %v", err)
+		}
+		if code := exitError.ExitCode(); code != blockExitCodeInterrupt {
+			t.Errorf("ExitCode: %d, want %d", code, blockExitCodeInterrupt)
+		}
+	}))
 
 	for i, tc := range containerTestCases {
 		t.Run(tc.name, func(t *testing.T) {
@@ -214,6 +207,46 @@ func hostnameFromTestCase(name string) string {
 	return "test-" + strings.Join(strings.Fields(name), "-")
 }
 
+func testContainerCancel(
+	containerExtra func(c *container.Container),
+	waitCheck func(t *testing.T, c *container.Container),
+) func(t *testing.T) {
+	return func(t *testing.T) {
+		ctx, cancel := context.WithTimeout(t.Context(), helperDefaultTimeout)
+
+		c := helperNewContainer(ctx, "block")
+		c.Stdout, c.Stderr = os.Stdout, os.Stderr
+		c.WaitDelay = helperDefaultTimeout
+		if containerExtra != nil {
+			containerExtra(c)
+		}
+
+		ready := make(chan struct{})
+		if r, w, err := os.Pipe(); err != nil {
+			t.Fatalf("cannot pipe: %v", err)
+		} else {
+			c.ExtraFiles = append(c.ExtraFiles, w)
+			go func() {
+				defer close(ready)
+				if _, err = r.Read(make([]byte, 1)); err != nil {
+					panic(err.Error())
+				}
+			}()
+		}
+
+		if err := c.Start(); err != nil {
+			hlog.PrintBaseError(err, "start:")
+			t.Fatalf("cannot start container: %v", err)
+		} else if err = c.Serve(); err != nil {
+			hlog.PrintBaseError(err, "serve:")
+			t.Errorf("cannot serve setup params: %v", err)
+		}
+		<-ready
+		cancel()
+		waitCheck(t, c)
+	}
+}
+
 func TestContainerString(t *testing.T) {
 	c := container.New(t.Context(), "ldd", "/usr/bin/env")
 	c.SeccompFlags |= seccomp.AllowMultiarch
@@ -227,12 +260,21 @@ func TestContainerString(t *testing.T) {
 	}
 }
 
+const (
+	blockExitCodeInterrupt = 2
+)
+
 func init() {
 	helperCommands = append(helperCommands, func(c command.Command) {
 		c.Command("block", command.UsageInternal, func(args []string) error {
 			if _, err := os.NewFile(3, "sync").Write([]byte{0}); err != nil {
 				return fmt.Errorf("write to sync pipe: %v", err)
 			}
+			{
+				sig := make(chan os.Signal, 1)
+				signal.Notify(sig, os.Interrupt)
+				go func() { <-sig; os.Exit(blockExitCodeInterrupt) }()
+			}
 			select {}
 		})