[Logcheck-devel] Bug#630721: logcheck: improve support for non-POSIX charsets in generated report

[Nenad Cimerman]

Package: logcheck
Version: 1.2.69
Severity: normal
Tags: l10n

My system is setup with non-POSIX default locale (see below), using UTF-8 
character encoding.
This leads to many lines inside various log files (e.g. /var/log/syslog)
containing 'german umlaut' characters (äöüÄÖÜß). During normal system usage
in bash, less, vi etc. everything works as expected - all characters are shown
correctly.
However, logcheck behaves different: report sent by e-mail contain unreadable
characters instead of 'german umlaut' characters.
Before sending this bug report, I investigated thoroughly what is causing the
problem and was able to find the culprit. I was also able to solve the problem
for me - but it did cost me a couple of hours, which is driving me to report 
this as a bug.
To be clear about this issue: I'm totally aware, that system log files may
contain all kind of encoded characters, making this problem really unsolvable 
in a 100% complete manner.
On the other hand, in real life things can be improved significantly, using a
more lax approach. In fact I believe, that most systems are using only one 
locale for system administration, which makes the solution of this problem (at
least in my case) quite simple.


........Details.......

The script /usr/sbin/logcheck is usually run by the cron deamon, based on 
/etc/cron.d/logcheck. This process runs in POSIX locale (LC_ALL=POSIX, 
LANG=POSIX), despite /etc/default/locale being possibly set to a different
locale.
Inside /usr/sbin/logcheck, the function sendreport() uses mail(1) or nail(1)
to deliver the report via e-mail. Additionally, sending report as an 
attachment depends on nail(1) beeing installed.
By default, reports are sent 'inline' (not as an attachment), which results
in mail(1) beeing used.
Unfortunately mail(1) is responsible for the characterset issue, as it does
ignore the locale settings completely.
All of this could be simplified and improved, when using mutt(1) instead:
+ produces correct encoding of e-mails, depending on locale settings
+ is able to send attachments using '-a' option

In my case, I did the following to solve the problem:
1. added the following line to /etc/cron.d/logcheck
   LC_ALL=de_DE.UTF-8
2. changed sendreport() funtion in /usr/sbin/logcheck:
	sendreport() {
	    MAILER=${MAILER:-mutt}
	    if [ $REBOOT -eq 1 ]; then
	        subject="Reboot: $HOSTNAME $DATE $*"
	    else
	        subject="$HOSTNAME $DATE $*"
	    fi
	    if [ $ADDTAG = "yes" ]; then
	        subject="[logcheck] $subject"
	    fi
	
	    if [ $MAILOUT -eq 1 ]; then
	        debug "Sending report to STDOUT"
	        cat $TMPDIR/report
	        debug "Sent report to STDOUT"
	    else
	        debug "Sending report: '$subject' to $SENDMAILTO"
	        if [ $MAILASATTACH -eq 1 ]; then
	          debug "Sending report as attachment"
	          if command -v $MAILER >/dev/null; then
	            echo -e "Report attached" | $MAILER -s "$subject" -a "$TMPDIR/report" "$SENDMAILTO"
	            return $?
	          else
	            echo >> $TMPDIR/report
	            echo Could not send report as attachment, $MAILER not installed >> $TMPDIR/report
	          fi
	        fi
	        cat $TMPDIR/report | $MAILER -s "$subject" "$SENDMAILTO"
	    fi
	}

Here is the diff-output showing my changes:
# diff /usr/sbin/logcheck logcheck 
284d283
<     MAILER=${MAILER:-mutt}
302,303c301,302
<           if command -v $MAILER >/dev/null; then
<             echo -e "Report attached" | $MAILER -s "$subject" -a "$TMPDIR/report" "$SENDMAILTO"
---
>           if command -v nail >/dev/null; then
>             echo -e "Report attached" | nail -s "$subject" -a "$TMPDIR/report" "$SENDMAILTO"
307c306
<             echo Could not send report as attachment, $MAILER not installed >> $TMPDIR/report
---
>             echo Could not send report as attachment, nail not installed >> $TMPDIR/report
310c309
<         cat $TMPDIR/report | $MAILER -s "$subject" "$SENDMAILTO"
---
>         cat $TMPDIR/report | mail -s "$subject" "$SENDMAILTO"
319a319
>    

Regards,
Nenad.

-- System Information:
Debian Release: 5.0.8
  APT prefers oldstable
  APT policy: (500, 'oldstable')
Architecture: i386 (i686)

Kernel: Linux 2.6.26-2-686 (SMP w/1 CPU core)
Locale: LANG=de_DE.UTF-8, LC_CTYPE=de_DE.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/bash

Versions of packages logcheck depends on:
ii  adduser            3.110                 add and remove users and groups
ii  bsd-mailx [mailx]  8.1.2-0.20071201cvs-3 A simple mail user agent
ii  cron               3.0pl1-105            management of regular background p
ii  exim4              4.69-9+lenny4         metapackage to ease Exim MTA (v4) 
ii  exim4-daemon-heavy 4.69-9+lenny4         Exim MTA (v4) daemon with extended
ii  lockfile-progs     0.1.11-0.1            Programs for locking and unlocking
ii  logtail            1.2.69                Print log file lines that have not
ii  mailx              1:20071201-3          Transitional package for mailx ren
ii  rsyslog [system-lo 3.18.6-4              enhanced multi-threaded syslogd

Versions of packages logcheck recommends:
ii  logcheck-database             1.2.69     database of system log rules for t

Versions of packages logcheck suggests:
pn  syslog-summary                <none>     (no description available)

-- no debconf information