diff --git a/ffserver.c b/ffserver.c
index 526cbfcae3cd7a74144a8e63438caebcb6864ceb..577ca6ff459daea9e0f406934ec59f379c58b0d5 100644
--- a/ffserver.c
+++ b/ffserver.c
@@ -305,15 +305,19 @@ static void ffm_set_write_index(AVFormatContext *s, int64_t pos,
     ffm->file_size = file_size;
 }
 
-static char *ctime1(char *buf2, int buf_size)
+static char *ctime1(char *buf2, size_t buf_size)
 {
     time_t ti;
     char *p;
 
     ti = time(NULL);
     p = ctime(&ti);
+    if (!p || !*p) {
+        *buf2 = '\0';
+        return buf2;
+    }
     av_strlcpy(buf2, p, buf_size);
-    p = buf2 + strlen(p) - 1;
+    p = buf2 + strlen(buf2) - 1;
     if (*p == '\n')
         *p = '\0';
     return buf2;