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From Michael Michalowski <>
Subject [users@httpd] difference of piped logs in Apache 1.3x and 2.x
Date Wed, 03 Mar 2004 17:01:17 GMT
hi folks,

I have a question concerning the piped log mechanism of Apache. It
makes it possible to treat a proram like a logfile and pipe the
Apache log stream to it. This feature is also available in Apache 2.0,
but I noticed a changed behaviour. Maybe I used an "undocumented
feature" in Apache 1.3x, but I like to ask whether I can emulate the
old behaviour with Apache 2 or not.

So, here is an example which worked in Apache 1.3x:

CustomLog "| program1 | program2" format

It gives the logstream to the first program "program1" and this
programm pipes it's output to the second program "program2". This
definitely worked in Apache 1.3x, but an Apache 2 makes '| program2'
to a simple parameter list of program1 (no more shell interpolation).

Another example would be something like that:

CustomLog "| program1 > /tmp/logfile 2> /tmp/errfile" format

In Apache 1.3x this would log to program1 and print it's output to
logfiles in the /tmp directory (shell interpolated). But for Apache 2.x
the '> /tmp/logfile 2> /tmp/errfile'-part is just a parameter string
for program1.

So, I think the piped log mechanism is a rewrite in Apache 2 and there
might be security issues, that prevent the old behaviour.
Or is it possible to have the old Apache 1.3x behaviour in an Apache2?
If so, please tell me how =)

best regards,
Michael Michalowski

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