rdctl: Don't use process groups on Linux

Disable killing all processes in the process on Linux, as Electron does not
create a new process group when running from the RPM/deb package.  Leave it
using process groups on macOS, as launchd still does it.

It is expected that we will revert this once we sort out process groups on
Linux.

Signed-off-by: Mark Yen <mark.yen@suse.com>

src/go/rdctl/cmd/internalProcessWaitKill.go

@@ -20,7 +20,11 @@ limitations under the License.
 package cmd
 
 import (
+	"errors"
 	"fmt"
+	"os"
+	"runtime"
+	"syscall"
 
 	"github.com/rancher-sandbox/rancher-desktop/src/go/rdctl/pkg/process"
 	"github.com/spf13/cobra"
@@ -39,6 +43,20 @@ exit, and once it does, terminates all processes within the same process group.`
 		if err != nil {
 			return fmt.Errorf("failed to get process ID: %w", err)
 		}
+		if runtime.GOOS == "linux" {
+			// TODO: We can't use the process group on Linux, because Electron does
+			// not always create a new one.
+			proc, err := os.FindProcess(pid)
+			if err != nil {
+				return fmt.Errorf("failed to find process for pid %d: %w", pid, err)
+			}
+			// The pid might not exist even if we did not receive an error.
+			err = proc.Signal(syscall.SIGTERM)
+			if err != nil && !errors.Is(err, os.ErrProcessDone) {
+				return fmt.Errorf("failed to terminate process %d: %w", pid, err)
+			}
+			return nil
+		}
 		return process.KillProcessGroup(pid, true)
 	},
 }

src/go/rdctl/pkg/shutdown/shutdown.go

@@ -237,17 +237,21 @@ func terminateRancherDesktopFunc(appDir string) func(context.Context) error {
 	return func(ctx context.Context) error {
 		var errors *multierror.Error
 
-		errors = multierror.Append(errors, (func() error {
-			mainExe, err := p.GetMainExecutable(ctx)
-			if err != nil {
-				return err
-			}
-			pid, err := process.FindPidOfProcess(mainExe)
-			if err != nil {
-				return err
-			}
-			return process.KillProcessGroup(pid, false)
-		})())
+		// TODO: We can't use the process group on Linux, because Electron does
+		// not always create a new one.
+		if runtime.GOOS != "linux" {
+			errors = multierror.Append(errors, (func() error {
+				mainExe, err := p.GetMainExecutable(ctx)
+				if err != nil {
+					return err
+				}
+				pid, err := process.FindPidOfProcess(mainExe)
+				if err != nil {
+					return err
+				}
+				return process.KillProcessGroup(pid, false)
+			})())
+		}
 
 		errors = multierror.Append(errors, process.TerminateProcessInDirectory(appDir, true))