Check open mode for files in memory

src/civetweb.c

@@ -1954,6 +1954,9 @@ mg_get_valid_options(void)
 }
 
 
+/* Do not open file (used in is_file_in_memory) */
+#define MG_FOPEN_MODE_NONE (0)
+
 /* Open file for read only access */
 #define MG_FOPEN_MODE_READ (1)
 
@@ -1978,6 +1981,10 @@ open_file_in_memory(const struct mg_connection *conn,
 		return 0;
 	}
 
+	if ((mode != MG_FOPEN_MODE_NONE) && (mode != MG_FOPEN_MODE_READ)) {
+		return 0;
+	}
+
 	if (conn->ctx->callbacks.open_file) {
 		buf = conn->ctx->callbacks.open_file(conn, path, &size);
 		if (buf != NULL) {
@@ -2012,7 +2019,7 @@ open_file_in_memory(const struct mg_connection *conn,
 static int
 is_file_in_memory(const struct mg_connection *conn, const char *path)
 {
-	return open_file_in_memory(conn, path, NULL, 0);
+	return open_file_in_memory(conn, path, NULL, MG_FOPEN_MODE_NONE);
 }