diff --git a/libc/bionic/fcntl.cpp b/libc/bionic/fcntl.cpp
new file mode 100644
index 0000000..c508131
--- /dev/null
+++ b/libc/bionic/fcntl.cpp
@@ -0,0 +1,76 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <stdarg.h>
+#include <fcntl.h>
+
+#include "private/bionic_fdtrack.h"
+
+#if defined(__LP64__)
+
+extern "C" int __fcntl(int fd, int cmd, ...);
+
+int fcntl(int fd, int cmd, ...) {
+  va_list args;
+  va_start(args, cmd);
+
+  // This is a bit sketchy, especially because arg can be an int, but all of our
+  // supported 64-bit ABIs pass arg in a register.
+  void* arg = va_arg(args, void*);
+  va_end(args);
+
+  int rc = __fcntl(fd, cmd, arg);
+  if (cmd == F_DUPFD) {
+    return FDTRACK_CREATE_NAME("F_DUPFD", rc);
+  } else if (cmd == F_DUPFD_CLOEXEC) {
+    return FDTRACK_CREATE_NAME("F_DUPFD_CLOEXEC", rc);
+  }
+  return rc;
+}
+
+#else
+
+extern "C" int __fcntl64(int, int, ...);
+
+// For fcntl we use the fcntl64 system call to signal that we're using struct flock64.
+int fcntl(int fd, int cmd, ...) {
+  va_list ap;
+
+  va_start(ap, cmd);
+  void* arg = va_arg(ap, void*);
+  va_end(ap);
+
+  if (cmd == F_DUPFD) {
+    return FDTRACK_CREATE_NAME("F_DUPFD", __fcntl64(fd, cmd, arg));
+  } else if (cmd == F_DUPFD_CLOEXEC) {
+    return FDTRACK_CREATE_NAME("F_DUPFD_CLOEXEC", __fcntl64(fd, cmd, arg));
+  }
+  return __fcntl64(fd, cmd, arg);
+}
+
+#endif