Add prepare-redhat script

prepare-nondebian does not work on RedHat machines running MySQL as the
paths are different, so providing a fixed version. prepare-nondebian has
historically been used more widely than just RedHat, hence the decision
to provide a RedHat-specific version and not just edit it.

ROOT/DEBIAN/control

@@ -3,6 +3,6 @@ Priority: optional
 Section: otherosfs
 Maintainer: Chemistry COs <support@ch.cam.ac.uk>
 Architecture: all
-Version: 0.9-ch77
+Version: 0.9-ch78
 Depends: zfs-dkms, postgresql-13 | postgresql-9.5 | postgresql-9.4 , liblockfile-simple-perl, libdbi-perl, libjson-perl, libzfs-perl-chem, libnet-openssh-perl, libdbd-pg-perl, mbuffer, rsync, nfs-kernel-server, pv, libwww-curl-perl
 Description: a backup system using ZFS (repository 'backup-scheduler')

ROOT/etc/chem-zfs-backup-server/zfs-rsync.d/prepare-redhat

+#!/bin/bash
+#set -x
+# A script which runs, largely on the remote machine, to prepare for backup
+# Jobs to do: 
+# * Exclude files which are only found in packages
+# * List all packages which are installed
+# * (optionally) dump MySQL into a file
+# * (optionally) dump PostgreSQL into a file
+SERVER=$1
+if [ -z "$SERVER" ] ; then
+ echo $0 Server
+ exit 1
+fi
+(
+# Create some necessary files
+mkdir -p /etc/chem-zfs-backup-server/zfs-rsync.d/$SERVER
+touch /etc/chem-zfs-backup-server/zfs-rsync.d/$SERVER/exclude
+ssh root@$SERVER "
+ umask 077
+ mkdir -p /var/adm/backup
+ touch /var/adm/backup/packages
+ touch /var/adm/backup/package-files
+"
+mkdir -p /etc/rsnapshot/$SERVER
+scp -q root@$SERVER:/var/adm/backup/package-files /etc/rsnapshot/$SERVER/exclude
+
+ssh root@$SERVER "
+ # Ensure that things are not readable where they ought not to be
+ umask 077
+
+# Dump MySQL, if the root user has access
+if [ -f /etc/my.cnf ] ; then
+ SOCKET=`awk ' BEGIN {FLAG=0} (\$0 ~ /^\[/) {FLAG=0} (\$0 ~ /^\[mysqld\]/) {FLAG=1} (\$1=="socket" && FLAG==1) { print \$3 ; } ' </etc/my.cnf`
+ [ -S \$SOCKET ] && which mysqldump >/dev/null 2>&1 && mysqldump --all-databases >/var/adm/backup/mysql
+fi
+
+# Dump PostgresSQL, if the postgres user has access
+id postgres >/dev/null 2>&1 && [ -d /var/run/postgresql/ ] && [ -x /usr/bin/pg_dumpall ] && ( su -c 'pg_dumpall --oids --clean' postgres >/var/adm/backup/postgres || echo Postgres failed on $SERVER )
+
+# Dump LDAP, if we can
+which slapcat >/dev/null 2>&1 && slapcat >/var/adm/backup/ldap
+
+# Ignore exit status of this command
+true
+"
+echo Prepared $SERVER `date`
+) >/var/log/chem-zfs-backup-server/${SERVER}-prepare 2>&1