From 3281d502733b198697bd076ae71d278c0e8b1912 Mon Sep 17 00:00:00 2001
From: "Richard W.M. Jones" <rjones@redhat.com>
Date: Thu, 28 Apr 2016 15:58:05 +0100
Subject: [PATCH] launch: libvirt: Add a /dev/urandom-based virtio-rng device
 to the appliance.

It is safe to use /dev/urandom to seed the guest.  In libvirt 1.3.4
this silly restriction has been lifted.

This restores commit b2c845333f66d4d3135d3b6a8d4b992d6160bf0a.
See also commit 9423c16607259b30985c46d04db9958ec079aa42.

Thanks: Cole Robinson for doing the libvirt implementation.
(cherry picked from commit 2b9f58f87b0dc2553061b4d8b301ff8e08121cb7)
---
 src/launch-libvirt.c | 29 +++++++++++------------------
 1 file changed, 11 insertions(+), 18 deletions(-)

diff --git a/src/launch-libvirt.c b/src/launch-libvirt.c
index 96c5913..4c29409 100644
--- a/src/launch-libvirt.c
+++ b/src/launch-libvirt.c
@@ -1306,26 +1306,19 @@ construct_libvirt_xml_devices (guestfs_h *g,
     }
 #endif
 
-#if 0
-    /* This is disabled.  Pulling random numbers from /dev/random
-     * causes the appliance to pause for long periods.  We should
-     * use /dev/urandom, but for bogus reasons libvirt prevents that.
-     * https://bugzilla.redhat.com/show_bug.cgi?id=1074464#c7
+    /* Add a random number generator (backend for virtio-rng).  This
+     * requires Cole Robinson's patch to permit /dev/urandom to be
+     * used, which was added in libvirt 1.3.4.
      */
-    /* Add a random number generator (backend for virtio-rng). */
-    start_element ("rng") {
-      attribute ("model", "virtio");
-      start_element ("backend") {
-        attribute ("model", "random");
-        /* It'd be nice to do this, but libvirt says:
-         *   file '/dev/urandom' is not a supported random source
-         * Let libvirt pick /dev/random automatically instead.
-         * See also: https://bugzilla.redhat.com/show_bug.cgi?id=1074464
-         */
-        //string ("/dev/urandom");
+    if (params->data->libvirt_version >= 1003004) {
+      start_element ("rng") {
+        attribute ("model", "virtio");
+        start_element ("backend") {
+          attribute ("model", "random");
+          string ("/dev/urandom");
+        } end_element ();
       } end_element ();
-    } end_element ();
-#endif
+    }
 
     /* virtio-scsi controller. */
     start_element ("controller") {
-- 
2.7.4