Add a config file for storing rngd options

So rngd options can be adjusted and not overwritten on updates (bz1252175)
Disable pkcs11 and nist entropy sources by default (bz1252175#c21)

Signed-off-by: Vladis Dronov <vdronov@redhat.com>

rng-tools.spec

@@ -16,6 +16,7 @@ License:        GPLv2+
 URL:            https://github.com/nhorman/rng-tools
 Source0:        %{url}/archive/v%{version}/%{name}-%{version}.tar.gz
 Source1:        rngd.service
+Source2:        rngd.sysconfig
 
 BuildRequires: gcc make
 BuildRequires: gettext
@@ -63,6 +64,8 @@ Hardware random number generation tools.
 
 # install systemd unit file
 install -Dt %{buildroot}%{_unitdir} -m0644 %{SOURCE1}
+# install sysconfig file
+install -D %{SOURCE2} -m0644 %{buildroot}%{_sysconfdir}/sysconfig/rngd
 
 %post
 %systemd_post rngd.service
@@ -81,13 +84,15 @@ install -Dt %{buildroot}%{_unitdir} -m0644 %{SOURCE1}
 %{_sbindir}/rngd
 %{_mandir}/man1/rngtest.1.*
 %{_mandir}/man8/rngd.8.*
-%attr(0644,root,root)   %{_unitdir}/rngd.service
+%attr(0644,root,root)    %{_unitdir}/rngd.service
+%config(noreplace) %attr(0644,root,root)    %{_sysconfdir}/sysconfig/rngd
 
 %changelog
-* Sat Sep 18 2021 Vladis Dronov <vdronov@redhat.com> - 6.14-1.git.56626083
+* Mon Sep 20 2021 Vladis Dronov <vdronov@redhat.com> - 6.14-1.git.56626083
 - Update to the upstream v6.14 + tip of origin/master @ 56626083
-- Add an important cb52458b and a revert of 2ce93190
+- Add an important 82f665c4 and a revert of 2ce93190
 - Add a fix for covscan unused variable warning
+- Add a config file for storing rngd options
 
 * Tue Sep 14 2021 Sahana Prasad <sahana@redhat.com> - 6.13-4.git.d207e0b6
 - Rebuilt with OpenSSL 3.0.0

rngd.service

@@ -2,8 +2,11 @@
 Description=Hardware RNG Entropy Gatherer Daemon
 ConditionVirtualization=!container
 
+# The "-f" option is required for the systemd service rngd to work with Type=simple
 [Service]
-ExecStart=/usr/sbin/rngd -f
+Type=simple
+EnvironmentFile=/etc/sysconfig/rngd
+ExecStart=/usr/sbin/rngd -f $RNGD_ARGS
 
 [Install]
 WantedBy=multi-user.target

rngd.sysconfig

@@ -0,0 +1,3 @@
+# Optional arguments passed to rngd. See rngd(8) and
+# https://bugzilla.redhat.com/show_bug.cgi?id=1252175#c21
+RNGD_ARGS="-x pkcs11 -x nist"