1 files changed, 57 insertions, 0 deletions
diff --git a/rdns_scan/zmap4rdns/lib/lockfd.c b/rdns_scan/zmap4rdns/lib/lockfd.c
new file mode 100644
index 0000000..093e819
--- /dev/null
+++ b/rdns_scan/zmap4rdns/lib/lockfd.c
@@ -0,0 +1,57 @@
+/*
+ * Copyright 2021 Regents of the University of Michigan
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <pthread.h>
+#include <assert.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "xalloc.h"
+
+static pthread_mutex_t **mutexes = NULL;
+
+static pthread_mutex_t *get_mutex(int fd)
+{
+	assert(fd < 3 && "todo: implement generically");
+	if (!mutexes) {
+		mutexes = xmalloc(3 * sizeof(char *));
+		assert(mutexes);
+	}
+	if (!mutexes[fd]) {
+		mutexes[fd] = xmalloc(sizeof(pthread_mutex_t));
+		assert(mutexes[fd]);
+		pthread_mutex_init(mutexes[fd], NULL);
+		assert(mutexes[fd]);
+	}
+	return mutexes[fd];
+}
+
+int lock_fd(int fd) { return pthread_mutex_lock(get_mutex(fd)); }
+
+int unlock_fd(int fd) { return pthread_mutex_unlock(get_mutex(fd)); }
+
+int lock_file(FILE *f)
+{
+	assert(f);
+	return lock_fd(fileno(f));
+}
+
+int unlock_file(FILE *f)
+{
+	assert(f);
+	return unlock_fd(fileno(f));
+}