Hello all,
I have been doing some testing on the results of httpd restart with
configuration errors.
This gave me some interesting results.
For these tests I build httpd trunk with APR trunk on Linux using the
following configure:
$ ./configure --prefix=/home/mrumph/apache25 --with-included-apr
--with-mpm=worker --enable-mpms-shared='worker'
Modify the default httpd.conf to include the following line:
Listen localhost:8080
Start the httpd server and verify the process information.
$ bin/apachectl -k start
$ ps -ef | grep -i httpd
Now restart httpd from this starting point with the following
configuration error cases:
Case 1: An unknown directive.
Add the following line to the httpd.conf file.
Xyzzy
bin/apachectl -k restart
- Returns with exit code 1 and following error message in stderr:
AH00526: Syntax error on line 198 of /home/mrumph/apache25/conf/httpd.conf:
Invalid command 'Xyzzy', perhaps misspelled or defined by a module not
included in the server configuration
httpd: abnormal exit 1
$ ps -ef | grep -i httpd
- The httpd server was not stopped and all of the previous processes
remain.
- And the logs/httpd.pid file remains intact.
$ tail logs/error_log
- No error message logged.
Case 2: A duplicate Listen directive.
Duplicate the Listen directive in the httpd.conf file.
Listen localhost:8080
Listen localhost:8080
$ bin/apachectl -k restart
- Returns with exit code 0 and no error message in stderr.
- So the httpd server appears to be working at this point.
- (But appearances are deceiving.)
$ ps -ef | grep -i httpd
- All of the httpd processes have stopped.
- But the logs/httpd.pid file remains intact.
$ tail logs/error_log
[Thu Mar 27 11:26:22.836887 2014] [mpm_worker:notice] [pid 2677:tid
47577479346656] AH00298: SIGHUP received. Attempting to restart
(98)Address already in use: AH00072: make_sock: could not bind to
address 127.0.0.1:8080
[Thu Mar 27 11:26:22.844003 2014] [mpm_worker:alert] [pid 2677:tid
47577479346656] no listening sockets available, shutting down
[Thu Mar 27 11:26:22.844031 2014] [core:emerg] [pid 2677:tid
47577479346656] AH00019: Unable to open logs, exiting
This was httpd trunk, but similar results are seen with httpd 2.2.22,
2.2-HEAD and 2.4.6.
Before working on this as a bug, I am trying to understand what should
be the correct behavior.
I think case 1 is working correctly.
But case 2 doesn't seem quite right.
First of all, it doesn't seem correct to have an httpd.pid file when all
of the httpd processes have vanished.
Secondly, it would be nice to see an error code from the apachectl -k
restart.
(But this is probably due to a different processing phase in the
validation for both of the cases.)
It is also a little strange to see a message "Unable to open logs" in
the log.
Does anyone have some opinions what the correct behavior should be for
these cases.
If there are some actual bugs here, I have some time available to work
on them.
Thanks,
Mike Rumph
