Harden backup and restore operations

internal/platform/mounts.go

@@ -8,6 +8,7 @@ import (
 	"os/exec"
 	"path/filepath"
 	"strings"
+	"time"
 
 	"git.casaderoll.de/michael/urbm/internal/model"
 )
@@ -66,13 +67,16 @@ func (m *MountManager) Prepare(ctx context.Context, repo model.Repository) (Moun
 			result.CredentialFile = f.Name()
 			if err := f.Chmod(0600); err != nil {
 				f.Close()
+				os.Remove(result.CredentialFile)
 				return result, err
 			}
 			if _, err := f.WriteString(credential); err != nil {
 				f.Close()
+				os.Remove(result.CredentialFile)
 				return result, err
 			}
 			if err := f.Close(); err != nil {
+				os.Remove(result.CredentialFile)
 				return result, err
 			}
 			options = append(options, "credentials="+result.CredentialFile)
@@ -97,5 +101,10 @@ func (m *MountManager) Cleanup(ctx context.Context, mounted MountedRepository) e
 	if !mounted.Mounted {
 		return nil
 	}
+	if _, hasDeadline := ctx.Deadline(); !hasDeadline {
+		var cancel context.CancelFunc
+		ctx, cancel = context.WithTimeout(ctx, 5*time.Second)
+		defer cancel()
+	}
 	return exec.CommandContext(ctx, "umount", mounted.Repository.Location).Run()
 }