From 69ea87350f8a2c20e00cbc8a5a53bd50702d532a Mon Sep 17 00:00:00 2001
From: dchagin <dchagin@FreeBSD.org>
Date: Sat, 18 Mar 2017 18:34:29 +0000
Subject: [PATCH] Implement getrandom() syscall. Note. GRND_RANDOM option is
 not supported for now.

MFC after:	1 month
---
 sys/amd64/linux/linux_dummy.c     |  1 -
 sys/amd64/linux32/linux32_dummy.c |  1 -
 sys/compat/linux/linux_misc.c     | 26 ++++++++++++++++++++++++++
 sys/compat/linux/linux_misc.h     |  4 ++++
 sys/i386/linux/linux_dummy.c      |  1 -
 5 files changed, 30 insertions(+), 3 deletions(-)

diff --git a/sys/amd64/linux/linux_dummy.c b/sys/amd64/linux/linux_dummy.c
index 90efd4e1f042..0a34dc121f1d 100644
--- a/sys/amd64/linux/linux_dummy.c
+++ b/sys/amd64/linux/linux_dummy.c
@@ -135,7 +135,6 @@ DUMMY(sched_getattr);
 DUMMY(renameat2);
 /* linux 3.15: */
 DUMMY(seccomp);
-DUMMY(getrandom);
 DUMMY(memfd_create);
 DUMMY(kexec_file_load);
 /* linux 3.18: */
diff --git a/sys/amd64/linux32/linux32_dummy.c b/sys/amd64/linux32/linux32_dummy.c
index da5e7571f08f..2c8d6b579e41 100644
--- a/sys/amd64/linux32/linux32_dummy.c
+++ b/sys/amd64/linux32/linux32_dummy.c
@@ -144,7 +144,6 @@ DUMMY(sched_getattr);
 DUMMY(renameat2);
 /* linux 3.15: */
 DUMMY(seccomp);
-DUMMY(getrandom);
 DUMMY(memfd_create);
 /* linux 3.18: */
 DUMMY(bpf);
diff --git a/sys/compat/linux/linux_misc.c b/sys/compat/linux/linux_misc.c
index 5a4fad2d3b55..2ce3be2b50e8 100644
--- a/sys/compat/linux/linux_misc.c
+++ b/sys/compat/linux/linux_misc.c
@@ -51,6 +51,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/proc.h>
 #include <sys/reboot.h>
 #include <sys/racct.h>
+#include <sys/random.h>
 #include <sys/resourcevar.h>
 #include <sys/sched.h>
 #include <sys/sdt.h>
@@ -65,6 +66,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/vnode.h>
 #include <sys/wait.h>
 #include <sys/cpuset.h>
+#include <sys/uio.h>
 
 #include <security/mac/mac_framework.h>
 
@@ -2508,3 +2510,27 @@ linux_to_bsd_waitopts(int options, int *bsdopts)
 	if (options & __WCLONE)
 		*bsdopts |= WLINUXCLONE;
 }
+
+int
+linux_getrandom(struct thread *td, struct linux_getrandom_args *args)
+{
+	struct uio uio;
+	struct iovec iov;
+
+	if (args->flags & ~(LINUX_GRND_NONBLOCK|LINUX_GRND_RANDOM))
+		return (EINVAL);
+	if (args->count > INT_MAX)
+		args->count = INT_MAX;
+
+	iov.iov_base = args->buf;
+	iov.iov_len = args->count;
+
+	uio.uio_iov = &iov;
+	uio.uio_iovcnt = 1;
+	uio.uio_resid = iov.iov_len;
+	uio.uio_segflg = UIO_USERSPACE;
+	uio.uio_rw = UIO_READ;
+	uio.uio_td = td;
+
+	return (read_random_uio(&uio, args->flags & LINUX_GRND_NONBLOCK));
+}
diff --git a/sys/compat/linux/linux_misc.h b/sys/compat/linux/linux_misc.h
index 826bd5002640..98ffd2263647 100644
--- a/sys/compat/linux/linux_misc.h
+++ b/sys/compat/linux/linux_misc.h
@@ -145,6 +145,10 @@ extern int stclohz;
 
 #define	LINUX_RLIM_INFINITY	(~0UL)
 
+/* Linux getrandom flags */
+#define	LINUX_GRND_NONBLOCK	0x0001
+#define	LINUX_GRND_RANDOM	0x0002
+
 int linux_common_wait(struct thread *td, int pid, int *status,
 			int options, struct rusage *ru);
 void linux_to_bsd_waitopts(int options, int *bsdopts);
diff --git a/sys/i386/linux/linux_dummy.c b/sys/i386/linux/linux_dummy.c
index bb5214205850..c025cecfc42f 100644
--- a/sys/i386/linux/linux_dummy.c
+++ b/sys/i386/linux/linux_dummy.c
@@ -140,7 +140,6 @@ DUMMY(sched_getattr);
 DUMMY(renameat2);
 /* linux 3.15: */
 DUMMY(seccomp);
-DUMMY(getrandom);
 DUMMY(memfd_create);
 /* linux 3.18: */
 DUMMY(bpf);