Bug 16761 - CustomLog with pipe spawns process during config
Summary: CustomLog with pipe spawns process during config
Alias: None
Product: Apache httpd-2
Classification: Unclassified
Component: mod_log_config (show other bugs)
Version: 2.0.44
Hardware: PC All
: P3 normal with 22 votes (vote)
Target Milestone: ---
Assignee: Apache HTTPD Bugs Mailing List
Depends on:
Reported: 2003-02-04 15:58 UTC by Martin Vilcans
Modified: 2006-10-31 11:32 UTC (History)
0 users

Patch to fix Hanging pipe logger processes. (183 bytes, patch)
2006-02-09 17:37 UTC, Kenneth Golomb
Details | Diff

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Description Martin Vilcans 2003-02-04 15:58:50 UTC
This bug appears when running the command apache -k install or apache -k config 
if there are CustomLog entries in the configuration that pipe to an external 
program (e.g. rotatelogs.exe). For each piping CustomLog, Apache creates the 
corresponding process. Then the Apache process exits, leaving the logging 
processes alive, probably waiting for input on stdin (which will never come, 
since the process isn't attached to a console).

To reproduce the bug, change the CustomLog line in the default httpd.conf to:

CustomLog "|/apache2/bin/rotatelogs.exe logs/access_%Y-%m-%d.log 86400 +60" 

Then execute apache -k install -f conf/httpd.conf. When the command is 
finished, check the Task Manager (or a better tool, such as Process Explorer) 
for a rotatelogs.exe process which must be killed manually.

This bug also appears with a simple test logger, so the bug is not specific to 
Comment 1 Scott Parker 2003-03-09 22:23:27 UTC
I confirm this behavior with v2.0.44/Win2k. 
It also leaves a hung process when service starts up and does not send to the
stdin on the log processor. This behavior is with "rotatelogs.exe" or
"cronolog.exe" So I don't think it is anything to do with the external programs
It does not have the problem with the ErrorLog directive. This works properly
piped to an external program.
Comment 2 Scott Parker 2003-03-10 04:04:51 UTC
v2.0.43 is not affected... compiled and tested on same system as 2.0.44.
Comment 3 Kenneth Golomb 2006-02-09 17:37:01 UTC
Created attachment 17630 [details]
Patch to fix Hanging pipe logger processes.

It looks like on Win32 of log.c the piped log always starts the piped process
thru a cmd.exe shell.  Which seems to be the root of this hanging piped
CustomLog / ErrorLog.  

Changing the process creation from:
apr_procattr_cmdtype_set(procattr, APR_SHELLCMD_ENV)			       
apr_procattr_cmdtype_set(procattr, APR_PROGRAM_ENV)			       

Will cause it to act the way it used and make it worrk correctly.

CMD.exe will then only be utilize for .cmd and .bat loggers where it is
Comment 4 Liam Hoekenga 2006-08-16 15:13:45 UTC
We've run into this problem on linux w/ httpd 2.2.x using ErrorLog - both with
rotatelogs and cronolog. 
Comment 5 toadie 2006-10-31 10:18:41 UTC
The proposed patch seems to work for us on Apache 2.2.3.  
Comment 6 Ruediger Pluem 2006-10-31 11:32:00 UTC
(In reply to comment #4)
> We've run into this problem on linux w/ httpd 2.2.x using ErrorLog - both with
> rotatelogs and cronolog. 

Have you checked if your problem is solved by the patch for Bug 40651