fix(execd): auto-recreate temp dir in stdLogDescriptor and combinedOutputDescriptor

components/execd/pkg/runtime/command_common.go

@@ -17,6 +17,7 @@ package runtime
 import (
 	"bufio"
 	"bytes"
+	"fmt"
 	"io"
 	"os"
 	"path/filepath"
@@ -60,20 +61,32 @@ func (c *Controller) storeCommandKernel(sessionID string, kernel *commandKernel)
 }
 
 // stdLogDescriptor creates temporary files for capturing command output.
+// It ensures the temp directory exists before opening files, so that commands
+// continue to work even after the /tmp directory has been removed and recreated.
 func (c *Controller) stdLogDescriptor(session string) (io.WriteCloser, io.WriteCloser, error) {
+	logDir := os.TempDir()
+	if err := os.MkdirAll(logDir, 0o755); err != nil {
+		return nil, nil, fmt.Errorf("failed to create temp dir %s: %w", logDir, err)
+	}
+
 	stdout, err := os.OpenFile(c.stdoutFileName(session), os.O_RDWR|os.O_CREATE|os.O_TRUNC, os.ModePerm)
 	if err != nil {
 		return nil, nil, err
 	}
 	stderr, err := os.OpenFile(c.stderrFileName(session), os.O_RDWR|os.O_CREATE|os.O_TRUNC, os.ModePerm)
 	if err != nil {
+		stdout.Close()
 		return nil, nil, err
 	}
 
 	return stdout, stderr, nil
 }
 
 func (c *Controller) combinedOutputDescriptor(session string) (io.WriteCloser, error) {
+	logDir := os.TempDir()
+	if err := os.MkdirAll(logDir, 0o755); err != nil {
+		return nil, fmt.Errorf("failed to create temp dir %s: %w", logDir, err)
+	}
 	return os.OpenFile(c.combinedOutputFileName(session), os.O_RDWR|os.O_CREATE|os.O_TRUNC, os.ModePerm)
 }
 

components/execd/pkg/runtime/command_test.go

@@ -253,3 +253,60 @@ func TestRunCommand_Error(t *testing.T) {
 		t.Fatalf("unexpected error payload: %+v", gotErr)
 	}
 }
+
+// TestStdLogDescriptor_AutoCreatesTempDir verifies that stdLogDescriptor
+// recreates the temp directory when it has been deleted, rather than failing.
+// Regression test for https://github.com/alibaba/OpenSandbox/issues/400.
+func TestStdLogDescriptor_AutoCreatesTempDir(t *testing.T) {
+	if goruntime.GOOS == "windows" {
+		t.Skip("TMPDIR env var has no effect on Windows")
+	}
+
+	// Point os.TempDir() at a path that does not yet exist.
+	missingDir := filepath.Join(t.TempDir(), "deleted_tmp")
+	t.Setenv("TMPDIR", missingDir)
+
+	c := NewController("", "")
+	stdout, stderr, err := c.stdLogDescriptor("test-session")
+	if err != nil {
+		t.Fatalf("stdLogDescriptor failed with missing temp dir: %v", err)
+	}
+	stdout.Close()
+	stderr.Close()
+
+	// The directory must have been created.
+	info, err := os.Stat(missingDir)
+	if err != nil {
+		t.Fatalf("expected temp dir to be created, stat error: %v", err)
+	}
+	if !info.IsDir() {
+		t.Fatalf("expected %s to be a directory", missingDir)
+	}
+}
+
+// TestCombinedOutputDescriptor_AutoCreatesTempDir verifies that
+// combinedOutputDescriptor also recreates the temp directory when missing.
+// Regression test for https://github.com/alibaba/OpenSandbox/issues/400.
+func TestCombinedOutputDescriptor_AutoCreatesTempDir(t *testing.T) {
+	if goruntime.GOOS == "windows" {
+		t.Skip("TMPDIR env var has no effect on Windows")
+	}
+
+	missingDir := filepath.Join(t.TempDir(), "deleted_tmp")
+	t.Setenv("TMPDIR", missingDir)
+
+	c := NewController("", "")
+	f, err := c.combinedOutputDescriptor("test-session")
+	if err != nil {
+		t.Fatalf("combinedOutputDescriptor failed with missing temp dir: %v", err)
+	}
+	f.Close()
+
+	info, err := os.Stat(missingDir)
+	if err != nil {
+		t.Fatalf("expected temp dir to be created, stat error: %v", err)
+	}
+	if !info.IsDir() {
+		t.Fatalf("expected %s to be a directory", missingDir)
+	}
+}