CA-407370: Use remote.conf for customer rsyslog forwarding rules (xapi-project#6328)

XenServer does not protect `/etc/rsyslog.d/xenserver.conf` when updating
the rsyslog package (or the xenserver-release package on CH8.2CU1), as a
result it is replaced with a fresh instance during updates which will
lose customer configurations (if they have any).
This script is primarily invoked via XenCenter when providing a new host
for log forwarding.
An update will be made to the XenServer rsyslog package to make it clear
that `/etc/rsyslog.d/xenserver.conf` should not be edited by the
customer.

I've tested this by copying the updated script onto my DT box and using
XenCenter to add a new log server - noting the new
`/etc/rsyslog.d/custom.conf` file and the untouched
`/etc/rsyslog.d/xenserver.conf` file.

Author: robhoes

scripts/xe-syslog-reconfigure

@@ -14,32 +14,12 @@ do
   shift
 done
 
-if [ -r /etc/syslog.conf ]; then
-  conf_file=/etc/syslog.conf
-  service=syslog
-fi
-
-if [ -r /etc/rsyslog.conf ]; then
-  conf_file=/etc/rsyslog.conf
-  service=rsyslog
-fi
-
-if [ -r /etc/rsyslog.d/xenserver.conf ]; then
-  conf_file=/etc/rsyslog.d/xenserver.conf
-  service=rsyslog
-fi
-
-if [ -z "$service" ]; then
-  echo "Error: unable to determine syslog service" >&2
-  exit 1
-fi
 
-sed -e '/^\*\.\*.*[@~]/ d' $conf_file >/etc/syslog.$$
 if [ $remote -eq 1 ]; then
-  echo -e "*.* @$host\n*.* ~" >>/etc/syslog.$$
+  echo "# /etc/rsyslog.d/remote.conf is auto-generated by xe-syslog-reconfigure" > /etc/rsyslog.d/remote.conf
+  echo "*.* @$host" >> /etc/rsyslog.d/remote.conf
 else
-  echo "*.* ~" >>/etc/syslog.$$
+  rm -f /etc/rsyslog.d/remote.conf
 fi
 
-[ -s /etc/syslog.$$ ] && mv -f /etc/syslog.$$ $conf_file
-systemctl restart $service
+systemctl restart rsyslog