Implement the CloudABI random_get() system call.

The random_get() system call works similar to getentropy()/getrandom()
on OpenBSD/Linux. It fills a buffer with random data.

This change introduces a new function, read_random_uio(), that is used
to implement read() on the random devices. We can call into this
function from within the CloudABI compatibility layer.

Approved by:	secteam
Reviewed by:	jmg, markm, wblock
Obtained from:	https://github.com/NuxiNL/freebsd
Differential Revision:	https://reviews.freebsd.org/D3053

1 files changed, 7 insertions, 0 deletions

diff --git a/sys/dev/random/randomdev.c b/sys/dev/random/randomdev.c
index e27b9095..f3339aa 100644
--- a/sys/dev/random/randomdev.c
+++ b/sys/dev/random/randomdev.c
@@ -152,6 +152,13 @@ static struct selinfo rsel;
 static int
 randomdev_read(struct cdev *dev __unused, struct uio *uio, int flags)
 {
+
+	return (read_random_uio(uio, (flags & O_NONBLOCK) != 0));
+}
+
+int
+read_random_uio(struct uio *uio, bool nonblock)
+{
 	uint8_t *random_buf;
 	int error;
 	ssize_t read_len, total_read, c;