[Bug 161331] perl sys::syslog formatting bug

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Summary: perl sys::syslog formatting bug


https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=161331


jvdias at redhat.com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |CLOSED
         Resolution|                            |NOTABUG




------- Additional Comments From jvdias at redhat.com  2005-11-02 19:08 EST -------
Yes, this happens in all currently shipped Red Hat perl versions .

I'm not sure this is really a bug - the 'man Sys::Syslog' man-page states:

"
       openlog $ident, $logopt, $facility
...
       syslog $priority, $format, @args
...
           If you didn’t use openlog() before using syslog(), syslog 
           will try to guess the $ident by extracting the shortest prefix 
           of $format that ends in a ":".
"

So what is happening is that since you specified no 'ident' for openlog,
Syslog.pm tries to extract the ident from the message, and thinks it is ':'.

The "ident" is then used to prefix the message, ie. is the message 'tag',
followed by ": " .

The 'tag' field is not optional, as shown by the prototype of the c
openlog call: 
    void openlog(const char *ident, int option, int facility);
The string pointed  to  by ident  is  prepended to every message, and is
typically set to the program name, and if the LOG_PID option is supplied,
it will be suffixed with the process id in brackets, to form the usual
syslog tag of 'program[pid]:' .

There are several ways to workaround this situation :

1. Provide an "ident" to openlog - eg., in your example:
  
$ perl -e 'use Sys::Syslog; openlog $0, "", ""; syslog "info", "::a"; closelog;'

This would emit the syslog line:
       <date> <host> -e: ::a

Usually $0 will be the name of the script, which is '-e' for perl command line
expressions .

2. Use a proper printf format as the second argument to syslog:

$ perl -e 'use Sys::Syslog;  syslog "info", "%s", "::a";'

logs the line:
       <date> <host> <user>: ::a

The openlog is optional, meaning that syslog will open a log socket for you.

Unless Sys::Syslog were to arbitrarily disallow an 'ident' value of ':', 
(which could be an executable file name), it cannot fix this bug and
still provide the feature of embedding the ident tag in the message.

So this is not a bug - use one of the workarounds given above.

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