checktrust: Add /usr/sbin/checktrust command

Add a script to determine whether the system has lost the trust of other
systems. Query a few remote systems which are supposed to be online most
of the time.

Note, that this script has a tristate result (trusted, not trusted,
unknown) so we don't communicate the result via exit status, but output
"trusted", "not trusted" or nothing.

checktrust/checktrust

@@ -0,0 +1,12 @@
+#! /usr/bin/bash
+
+for host in wtf afk pummelfee; do
+    reply="$(netcat -w 1 $host 236 </dev/null)"
+    if [ "$reply" = "I trust you" ]; then
+        echo "trusted"
+        exit
+    elif [ "$reply" = "I don't trust you" ]; then
+        echo "not trusted"
+        exit
+    fi
+done

install.sh

@@ -166,4 +166,5 @@ install_data misc_etc_files/rsyslog.conf "$DESTDIR$sysconfdir/rsyslog.conf"
 install_data crashkernel/crashkernel.service              "$DESTDIR$systemdunitdir/crashkernel.service"
 install_exec crashkernel/crash-recovery.sh                "$DESTDIR$root_sbindir/crash-recovery.sh"
 install_data misc_systemd_units/admin-sshd.service        "$DESTDIR$systemdunitdir/admin-sshd.service"
+install_exec checktrust/checktrust                        "$DESTDIR$usr_sbindir/checktrust"
 exit