diff --git a/libc/upstream-netbsd/extern.h b/libc/upstream-netbsd/extern.h
new file mode 100644
index 0000000..942e237
--- /dev/null
+++ b/libc/upstream-netbsd/extern.h
@@ -0,0 +1,22 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * 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.
+ */
+
+#ifndef _BIONIC_NETBSD_EXTERN_H_included
+#define _BIONIC_NETBSD_EXTERN_H_included
+
+// Placeholder.
+
+#endif
diff --git a/libc/upstream-netbsd/libc/gen/psignal.c b/libc/upstream-netbsd/libc/gen/psignal.c
new file mode 100644
index 0000000..4472be6
--- /dev/null
+++ b/libc/upstream-netbsd/libc/gen/psignal.c
@@ -0,0 +1,85 @@
+/*	$NetBSD: psignal.c,v 1.23 2012/03/13 21:13:36 christos Exp $	*/
+
+/*
+ * Copyright (c) 1983, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. 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.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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 <sys/cdefs.h>
+#if defined(LIBC_SCCS) && !defined(lint)
+#if 0
+static char sccsid[] = "@(#)psignal.c	8.1 (Berkeley) 6/4/93";
+#else
+__RCSID("$NetBSD: psignal.c,v 1.23 2012/03/13 21:13:36 christos Exp $");
+#endif
+#endif /* LIBC_SCCS and not lint */
+
+#include "namespace.h"
+
+#include <sys/types.h>
+#include <sys/uio.h>
+
+#include <limits.h>
+#include <signal.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "extern.h"
+
+#ifdef __weak_alias
+__weak_alias(psignal,_psignal)
+#endif
+
+void
+psignal(int sig, const char *s)
+{
+	struct iovec *v;
+	struct iovec iov[4];
+	char buf[NL_TEXTMAX];
+
+	v = iov;
+	if (s && *s) {
+		v->iov_base = __UNCONST(s);
+		v->iov_len = strlen(s);
+		v++;
+		v->iov_base = __UNCONST(": ");
+		v->iov_len = 2;
+		v++;
+	}
+	v->iov_base = __UNCONST(__strsignal((int)sig, buf, sizeof(buf)));
+	v->iov_len = strlen(v->iov_base);
+	v++;
+	v->iov_base = __UNCONST("\n");
+	v->iov_len = 1;
+	(void)writev(STDERR_FILENO, iov, (int)((v - iov) + 1));
+}
+
+void
+psiginfo(const siginfo_t *si, const char *s)
+{
+	psignal(si->si_signo, s);
+}