ui-snapshot: avoid segfault when no filename is specified

Signed-off-by: Lars Hjemli <hjemli@gmail.com>

1 files changed, 17 insertions, 6 deletions

diff --git a/ui-snapshot.c b/ui-snapshot.c
index f25613e..5372f5d 100644
--- a/ui-snapshot.c
+++ b/ui-snapshot.c
@@ -156,20 +156,31 @@ static const char *get_ref_from_filename(const char *url, const char *filename,
         return NULL;
 }
 
+void show_error(char *msg)
+{
+        ctx.page.mimetype = "text/html";
+        cgit_print_http_headers(&ctx);
+        cgit_print_docstart(&ctx);
+        cgit_print_pageheader(&ctx);
+        cgit_print_error(msg);
+        cgit_print_docend();
+}
+
 void cgit_print_snapshot(const char *head, const char *hex,
                          const char *filename, int snapshots, int dwim)
 {
         const struct cgit_snapshot_format* f;
         char *prefix = NULL;
 
+        if (!filename) {
+                show_error("No snapshot name specified");
+                return;
+        }
+
         f = get_format(filename);
         if (!f) {
-                ctx.page.mimetype = "text/html";
-                cgit_print_http_headers(&ctx);
-                cgit_print_docstart(&ctx);
-                cgit_print_pageheader(&ctx);
-                cgit_print_error(fmt("Unsupported snapshot format: %s", filename));
-                cgit_print_docend();
+                show_error(xstrdup(fmt("Unsupported snapshot format: %s",
+                                       filename)));
                 return;
         }