#! /bin/sh

# Copyright (c) 2003 University of Cambridge.
# See the file NOTICE for conditions of use and distribution.


# Shell script for cycling exim main and reject log files. Each time it is run,
# the files get "shuffled down" by one, the current one (e.g. mainlog) becoming
# mainlog.01, the previous mainlog.01 becoming mainlog.02, and so on, up to the
# limit configured here. The same happens to the reject logs. All those with
# numbers greater than 1 are compressed.

# This script should be called regularly (e.g. daily) by a root crontab
# entry of the form

# 1 0 * * *   /opt/exim/bin/exicyclog

# The following lines are generated from Exim's configuration file when
# this source is built into a script, but you can subsequently edit them
# without rebuilding things, as long are you are careful not to overwrite
# the script in the next Exim rebuild/install. "Keep" is the number of old log
# files that are required to be kept. "Compress" and "suffix" define your
# chosen compression method. The others are provided because the location
# of certain commands varies from OS to OS. Sigh.

keep=10
compress=/usr/bin/gzip
suffix=gz

chown=/usr/sbin/chown
chgrp=/usr/bin/chgrp
mv=/bin/mv
rm=/bin/rm

# End of editable lines
#########################################################################

# Some operating systems have different versions in which the commands live
# in different places. We have a fudge that will search the usual suspects if
# requested.

for cmd in chown chgrp mv rm ; do
  eval "oldcmd=\$$cmd"
  if [ "$oldcmd" != "look_for_it" ] ; then continue ; fi
  newcmd=$cmd
  for dir in /bin /usr/bin /usr/sbin /usr/etc ; do
    if [ -f $dir/$cmd ] ; then
      newcmd=$dir/$cmd
      break
    fi
  done
  eval $cmd=$newcmd
done

# See if this installation is using the esoteric "USE_EUID" feature of Exim,
# in which it uses the effective user id as a suffix for the configuration file
# name. In order for this to work, exicyclog must be run under the appropriate
# euid.

if [ "" = "yes" ]; then
  euid=.`id -u`
fi

# See if this installation is using the esoteric "USE_NODE" feature of Exim,
# in which it uses the host's name as a suffix for the configuration file name.

if [ "" = "yes" ]; then
  hostsuffix=.`uname -n`
fi

# Now find the configuration file name. This has got complicated because
# /usr/local/etc/exim/configure may now be a list of files. The one that is used is the first
# one that exists. Mimic the code in readconf.c by testing first for the
# suffixed file in each case.

set `awk -F: '{ for (i = 1; i <= NF; i++) print $i }' <<End
/usr/local/etc/exim/configure
End
`
while [ "$config" = "" -a $# -gt 0 ] ; do
  if [ -f "$1$euid$hostsuffix" ] ; then
    config="$1$euid$hostsuffix"
  elif [ -f "$1$euid" ] ; then
    config="$1$euid"
  elif [ -f "$1$hostsuffix" ] ; then
    config="$1$hostsuffix"
  elif [ -f "$1" ] ; then
    config="$1"
  fi
  shift
done

# Determine if the log file path is set, and where the spool directory is. The
# strings /usr/local/etc/exim/configure and /usr/local/sbin below are replaced by their compile-
# time settings when this source is build into a script. Search for an
# exim_path setting in the configure file; otherwise use the bin directory.
# Call that version of Exim to find the spool directory and log file path.
# BEWARE: a tab character is needed in the command below. It has had a nasty
# tendency to get lost in the past. Use a variable to hold a space and a tab to
# keep the tab in one place.

st='	 '
exim_path=`grep "^[$st]*exim_path" $config | sed "s/.*=[$st]*//"`
if test "$exim_path" = ""; then exim_path=/usr/local/sbin/exim; fi

spool_directory=`$exim_path -C $config -bP spool_directory | sed 's/.*=[  ]*//'`
log_file_path=`$exim_path -C $config -bP log_file_path | sed 's/.*=[  ]*//'`

# If log_file_path contains only "syslog" then no Exim log files are in use.
# We can't cycle anything. Complain and give up.

if [ "$log_file_path" = "syslog" ] ; then
  echo "*** Exim is logging to syslog - no log files to cycle ***"
  exit 1
fi

# Otherwise, remove ":syslog" or "syslog:" (some spaces allowed) and inspect
# what remains. The simplistic regex originally used failed when a filename
# contained "syslog", so we have to use three less general ones, because sed
# doesn't have much power in its regexs.

log_file_path=`echo "$log_file_path" | \
  sed 's/^ *:\{0,1\} *syslog *:\{0,1\} *//;s/: *syslog *:/:/;s/: *syslog *$//'`

# If log_file_path is empty, then the logs we are interested in are called
# "mainlog" and "rejectlog" in the directory called "log" in the spool
# directory. Otherwise we fish out the directory from the given path, and
# also the names of the logs.

if [ "$log_file_path" = "" ]; then
  logdir=$spool_directory/log
  mainlog=mainlog
  rejectlog=rejectlog
else
  logdir=`echo $log_file_path | sed 's?/[^/]*$??'`
  logbase=`echo $log_file_path | sed 's?^.*/??'`
  mainlog=`echo $logbase | sed 's/%s/main/'`
  rejectlog=`echo $logbase | sed 's/%s/reject/'`
fi

# Get into the log directory to do the business.

cd $logdir

# If there is no main log file, do nothing.

if [ ! -f $mainlog ]; then exit; fi

# Find out the owner and group of the main log file so that we can re-instate
# this on moved and compressed files, since some operating systems may change
# things. This is a tedious bit of code, but it should work both in operating
# systems where the -l option of ls gives the user and group, and those in which
# you need -lg. The condition is that, if the fifth field of the output from
# ls consists entirely of digits, then the third and fourth fields are the user
# and group.

a=`ls -lg $mainlog`
b=`ls -l  $mainlog`

# These statements work fine in the Bourne or Korn shells, but not in Bash.
# So for the benefit of systems whose /bin/sh is really Bash, they have been
# changed to a messier form.

# user=`echo "$a\n$b\n" | awk 'BEGIN { OFS=""} { if ($5 ~ /^[0-9]+$/) print $3; }'`
# group=`echo "$a\n$b\n" | awk 'BEGIN { OFS=""} { if ($5 ~ /^[0-9]+$/) print $4; }'`

user=`echo "$a
$b
" | awk 'BEGIN { OFS=""} { if ($5 ~ /^[0-9]+$/) { print $3; exit; } }'`

group=`echo "$a
$b
" | awk 'BEGIN { OFS=""} { if ($5 ~ /^[0-9]+$/) { print $4; exit; } }'`

# Now do the job. First remove the files that have "fallen off the bottom".
# Look for both the compressed and uncompressed forms.

if [ $keep -lt 10 ]; then keept=0$keep; else keept=$keep; fi;

if [ -f $mainlog.$keept ]; then $rm $mainlog.$keept; fi;
if [ -f $mainlog.$keept.$suffix ]; then $rm $mainlog.$keept.$suffix; fi;

if [ -f $rejectlog.$keept ]; then $rm $rejectlog.$keept; fi;
if [ -f $rejectlog.$keept.$suffix ]; then $rm $rejectlog.$keept.$suffix; fi;

# Now rename all the previous old files by increasing their numbers by 1.
# When the number is less than 10, insert a leading zero.

count=$keep
if [ $count -lt 10 ]; then countt=0$count; else countt=$count; fi;

while [ $count -gt 1 ]; do
  old=`expr $count - 1`
  if [ $old -lt 10 ]; then oldt=0$old; else oldt=$old; fi;
  if [ -f $mainlog.$oldt ]; then
    $mv $mainlog.$oldt $mainlog.$countt
  elif [ -f $mainlog.$oldt.$suffix ]; then
    $mv $mainlog.$oldt.$suffix $mainlog.$countt.$suffix
  fi
  if [ -f $rejectlog.$oldt ]; then
    $mv $rejectlog.$oldt $rejectlog.$countt
  elif [ -f $rejectlog.$oldt.$suffix ]; then
    $mv $rejectlog.$oldt.$suffix $rejectlog.$countt.$suffix
  fi
  count=$old
  countt=$oldt
done

# Now rename the current files as 01

if [ -f $mainlog ]; then
  $mv $mainlog $mainlog.01
  $chown $user:$group $mainlog.01
fi

if [ -f $rejectlog ]; then
  $mv $rejectlog $rejectlog.01
  $chown $user:$group $rejectlog.01
fi

# Now scan the 02 and later files, compressing where necessary, and
# ensuring that their owners and groups are correct.

count=2;

while [ $count -le $keep ]; do
  if [ $count -lt 10 ]; then countt=0$count; else countt=$count; fi
  if [ -f $mainlog.$countt ]; then $compress $mainlog.$countt; fi
  if [ -f $mainlog.$countt.$suffix ]; then
    $chown $user:$group $mainlog.$countt.$suffix
  fi
  if [ -f $rejectlog.$countt ]; then $compress $rejectlog.$countt; fi
  if [ -f $rejectlog.$countt.$suffix ]; then
    $chown $user:$group $rejectlog.$countt.$suffix
  fi
  count=`expr $count + 1`
done

# End of exicyclog
