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From Paras Fadte <plf...@gmail.com>
Subject Re: Using gzip and CustomLog
Date Tue, 10 Feb 2009 09:02:56 GMT
Hi Rainer,

I have attached the modified "rotatelogs.c" file (originally taken
from apache 2.0.55 ) . Can you please have a look at it and let me
know its shortcomings and chances that it could seg fault ?

Thanks in advance.

-Paras

On Tue, Feb 10, 2009 at 1:37 PM, Paras Fadte <plfgoa@gmail.com> wrote:
> Thanks Rainer.
>
> On Sun, Feb 8, 2009 at 8:50 PM, Rainer Jung <rainer.jung@kippdata.de> wrote:
>> On 28.01.2009 06:50, Paras Fadte wrote:
>>>
>>> I have somewhat modified the rotatlogs utility to support compression
>>> . Although it creates files in compressed format (.gz) and rotates
>>> them properly the issue that i am facing is that when apache is
>>> restarted (graceful or stop/start way ) the last created compressed
>>> file doesn't seem to get closed  . Is there a way to rectify this ?
>>> For compression I am using zlib .
>>
>> When httpd is restarted or stopped, then most rotatelogs processes get
>> stopped via a signal. The signal could depend on the platform, but in my
>> case it's SIGTERM. You can "truss" your rotatelogs to verify yourself,
>> whether that's true for your Linux system too. truss will show you the
>> signal the rotatelogs process received before terminating.
>>
>> Then you need to register a signal handler, e.g.
>>
>> apr_signal(SIG_TERM, my_signal_handler);
>>
>> which gets called automatically, whenever the process receives the
>> respective signal. Your signal handler my_signal_handler() could then set an
>> internal flag, indicating that you want to cleanup and exit rotatelogs.
>>
>> You can check this flag before and after the blocking read from the log
>> pipe, and if it is set, close your gzip output cleanly and exit rotatelogs.
>>
>> You can temporarily deactivate or activate all signal handlers for SIG_TERM
>> with
>>
>> apr_signal_unblock(SIG_TERM);
>>
>> and
>>
>> apr_signal_block(SIG_TERM);
>>
>> The ErrorLog for the global server behaves a little different, when
>> restarting Apache it doesn't get a signal but instead it will get an EPIPE
>> when trying to read from the log pipe.
>>
>> Regards,
>>
>> Rainer
>>
>>> On Fri, Jan 23, 2009 at 1:41 PM, Paras Fadte<plfgoa@gmail.com>  wrote:
>>>>
>>>> Thanks Rainer,
>>>>
>>>> yeah.. me not a pro at development .
>>>>
>>>> On Fri, Jan 23, 2009 at 1:30 PM, Rainer Jung<rainer.jung@kippdata.de>
>>>>  wrote:
>>>>>
>>>>> On 23.01.2009 08:45, Paras Fadte wrote:
>>>>>>
>>>>>> Can you please tell me in which file ?
>>>>>
>>>>> I assume you are building rotatelogs from within the httpd sources.
>>>>>
>>>>> There is a file support/Makefile, which contains a line
>>>>>
>>>>> $(LINK) $(rotatelogs_LTFLAGS) $(rotatelogs_OBJECTS) $(PROGRAM_LDADD)
>>>>>
>>>>> Simply add "-lz" at the end of the line:
>>>>>
>>>>> $(LINK) $(rotatelogs_LTFLAGS) $(rotatelogs_OBJECTS) $(PROGRAM_LDADD)
-lz
>>>>>
>>>>> In case you don't know what a Makefile is and how it basically works,
>>>>> you
>>>>> need to read about how to do C software development.
>>>>>
>>>>> Regards,
>>>>>
>>>>> Rainer
>>>>>
>>>>>> On Fri, Jan 23, 2009 at 1:09 PM, Rainer Jung<rainer.jung@kippdata.de>
>>>>>>  wrote:
>>>>>>>
>>>>>>> On 23.01.2009 07:55, Paras Fadte wrote:
>>>>>>>>
>>>>>>>> Hi,
>>>>>>>>
>>>>>>>> I get following error when I try to use "compress" function
of zlib
>>>>>>>> in
>>>>>>>>  "rotatelogs.c" . I have included "zlib.h" in rotatelogs.c
.
>>>>>>>>
>>>>>>>> /home/paras/httpd-2.0.55/support/rotatelogs.c:294: undefined
>>>>>>>> reference
>>>>>>>> to `compress'
>>>>>>>> collect2: ld returned 1 exit status
>>>>>>>>
>>>>>>>> Is it linking error ? where should I make the changes to
eliminate
>>>>>>>> this
>>>>>>>> error?
>>>>>>>
>>>>>>> Add -lz to the linking flags.
>>
>

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