diff --git a/libc/arch-x86_64/bionic/sigaction.c b/libc/arch-x86_64/bionic/sigaction.c
new file mode 100644
index 0000000..d5622be
--- /dev/null
+++ b/libc/arch-x86_64/bionic/sigaction.c
@@ -0,0 +1,52 @@
+/*
+ * Copyright (C) 2013 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 <signal.h>
+
+extern void __rt_sigreturn(void);
+extern int __rt_sigaction(int, const struct sigaction*, struct sigaction*, size_t);
+
+int sigaction(int sig, const struct sigaction* act, struct sigaction* old_act) {
+  struct sigaction sa;
+
+  if (act != NULL && !(act->sa_flags & SA_RESTORER)) {
+    sa = *act;
+    act = &sa;
+    sa.sa_flags |= SA_RESTORER;
+    sa.sa_restorer = &__rt_sigreturn;
+  }
+
+  int result = __rt_sigaction(sig, act, old_act, sizeof(sigset_t));
+
+  if (old_act != NULL && (old_act->sa_restorer == &__rt_sigreturn)) {
+    old_act->sa_flags &= ~SA_RESTORER;
+  }
+
+  return result;
+}
+