export-tar: refuse to write tar to a TTY

src/import/export.c

@@ -18,6 +18,7 @@
 #include "runtime-scope.h"
 #include "signal-util.h"
 #include "string-util.h"
+#include "terminal-util.h"
 #include "verbs.h"
 
 static ImportCompressType arg_compress = IMPORT_COMPRESS_UNKNOWN;
@@ -93,6 +94,9 @@ static int export_tar(int argc, char *argv[], void *userdata) {
         } else {
                 _cleanup_free_ char *pretty = NULL;
 
+                if (isatty_safe(STDOUT_FILENO))
+                        return log_error_errno(SYNTHETIC_ERRNO(EBADF), "Refusing to write archive to TTY.");
+
                 fd = STDOUT_FILENO;
 
                 (void) fd_get_path(fd, &pretty);