add support for a global temp path

Fixes #436

vfs/vfs.go

@@ -30,6 +30,7 @@ var (
 	// ErrVfsUnsupported defines the error for an unsupported VFS operation
 	ErrVfsUnsupported  = errors.New("not supported")
 	credentialsDirPath string
+	tempPath           string
 	sftpFingerprints   []string
 )
 
@@ -43,6 +44,16 @@ func GetCredentialsDirPath() string {
 	return credentialsDirPath
 }
 
+// SetTempPath sets the path for temporary files
+func SetTempPath(fsPath string) {
+	tempPath = fsPath
+}
+
+// GetTempPath returns the path for temporary files
+func GetTempPath() string {
+	return tempPath
+}
+
 // SetSFTPFingerprints sets the SFTP host key fingerprints
 func SetSFTPFingerprints(fp []string) {
 	sftpFingerprints = fp