1 files changed, 96 insertions, 0 deletions
diff --git a/sys/kern/sys_getrandom.c b/sys/kern/sys_getrandom.c
new file mode 100644
index 000000000000..67881a342a7b
--- /dev/null
+++ b/sys/kern/sys_getrandom.c
@@ -0,0 +1,96 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+ *
+ * Copyright (c) 2018 Conrad Meyer <cem@FreeBSD.org>
+ * 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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>
+__FBSDID("$FreeBSD$");
+
+#include <sys/param.h>
+#include <sys/errno.h>
+#include <sys/limits.h>
+#include <sys/proc.h>
+#include <sys/random.h>
+#include <sys/sysproto.h>
+#include <sys/systm.h>
+#include <sys/uio.h>
+
+#define GRND_VALIDFLAGS	(GRND_NONBLOCK | GRND_RANDOM)
+
+/*
+ * random_read_uio(9) returns EWOULDBLOCK if a nonblocking request would block,
+ * but the Linux API name is EAGAIN.  On FreeBSD, they have the same numeric
+ * value for now.
+ */
+CTASSERT(EWOULDBLOCK == EAGAIN);
+
+static int
+kern_getrandom(struct thread *td, void *user_buf, size_t buflen,
+    unsigned int flags)
+{
+	struct uio auio;
+	struct iovec aiov;
+	int error;
+
+	if ((flags & ~GRND_VALIDFLAGS) != 0)
+		return (EINVAL);
+	if (buflen > IOSIZE_MAX)
+		return (EINVAL);
+
+	if (buflen == 0) {
+		td->td_retval[0] = 0;
+		return (0);
+	}
+
+	aiov.iov_base = user_buf;
+	aiov.iov_len = buflen;
+	auio.uio_iov = &aiov;
+	auio.uio_iovcnt = 1;
+	auio.uio_offset = 0;
+	auio.uio_resid = buflen;
+	auio.uio_segflg = UIO_USERSPACE;
+	auio.uio_rw = UIO_READ;
+	auio.uio_td = td;
+
+	error = read_random_uio(&auio, (flags & GRND_NONBLOCK) != 0);
+	if (error == 0)
+		td->td_retval[0] = buflen - auio.uio_resid;
+	return (error);
+}
+
+#ifndef _SYS_SYSPROTO_H_
+struct getrandom_args {
+	void		*buf;
+	size_t		buflen;
+	unsigned int	flags;
+};
+#endif
+
+int
+sys_getrandom(struct thread *td, struct getrandom_args *uap)
+{
+	return (kern_getrandom(td, uap->buf, uap->buflen, uap->flags));
+}