Can a module control the socket transport protocol? - revisited
I'm revisiting this question (from several months ago), primarily because I know more now that I did then - though still not enough. :) There are a couple places in the httpd code that state or imply that httpd is not restricted to TCP - that other network transport protocols can be used. In particular, core.c:register_hooks() explicitly mentions other modules installing alternate network transports, and http_connection.h mentions the install_network_transport hook. I haven't been able to find any information at all on the install_network_transport hook, and I'm wondering if the comment is actually meant to refer to alternatives to HTTP, rather than TCP. I'm also wondering if the comment in core.c refers only to the core being network transport agnostic, and implies nothing about the MPMs, which appear to me to be effectively hard coded to TCP. Is it possible to add a loadable module to an MPM? If not, then it seems like the only option is to create my own MPM. If so, then the trick would be to get any sockets I create into the MPM's list of listening sockets, so they can be polled - but even that doesn't seem possible. The problem as I see it is that one of the key variables (the number of listening sockets), is private to the MPM. Does anyone really know if httpd can support alternate transport protocols? Does the comment in core.c simply indicate that the core is network transport agnostic, and imply nothing about the MPMs? Thanks for any help/comments on this. - Jon Leighton
mod_proxy reverse proxying and AH01179: balancer slotmem_create failed
As of late I'm seeing a lot of AH01179: balancer slotmem_create failed error messages which prevent apache2 from starting. I do have DefaultRuntimeDir /var/run/apache2 set. For some reasons there appear to be left-over .shm files in the DefaultRunTimeDir between stop-starts/restarts which then get picked up by mod_slotmem when mod_proxy asks it for shared memory. Unfortunately, those .shm files sometimes have the wrong size and get rejected by the mod_slotmem code due to size mismatch. To me it looks like this situation suffers from the same issue as reported in https://issues.apache.org/bugzilla/show_bug.cgi?id=55449 though I only have one user (nobody) for all the worker processes. I get the systems back up and running by deleting all .shm files in the DefaultRunTimeDir between stop-starts/restarts but this seems fragile to me. Another workaround, as crude as it is, seems to be disabling the reusing of existing shared memory segments by setting fbased = 0; in modules/slotmem/mod_slotmem_shm.c in slotmem_create(). Neither of those two appraoches seems right to me. I do need at least a temporary workaround since this is causing major havoc.
Re: mod_proxy reverse proxying and AH01179: balancer slotmem_create failed
Is BalancerPersist Off or On? Those .shm files should only stick around if we want to persist state across restarts. On Nov 6, 2013, at 8:39 AM, Thomas Eckert thomas.r.w.eck...@gmail.com wrote: As of late I'm seeing a lot of AH01179: balancer slotmem_create failed error messages which prevent apache2 from starting. I do have DefaultRuntimeDir /var/run/apache2 set. For some reasons there appear to be left-over .shm files in the DefaultRunTimeDir between stop-starts/restarts which then get picked up by mod_slotmem when mod_proxy asks it for shared memory. Unfortunately, those .shm files sometimes have the wrong size and get rejected by the mod_slotmem code due to size mismatch. To me it looks like this situation suffers from the same issue as reported in https://issues.apache.org/bugzilla/show_bug.cgi?id=55449 though I only have one user (nobody) for all the worker processes. I get the systems back up and running by deleting all .shm files in the DefaultRunTimeDir between stop-starts/restarts but this seems fragile to me. Another workaround, as crude as it is, seems to be disabling the reusing of existing shared memory segments by setting fbased = 0; in modules/slotmem/mod_slotmem_shm.c in slotmem_create(). Neither of those two appraoches seems right to me. I do need at least a temporary workaround since this is causing major havoc.
Re: mod_proxy reverse proxying and AH01179: balancer slotmem_create failed
It is not mentioned specifically in the configuration files, so it defaults to Off according to http://httpd.apache.org/docs/current/mod/mod_proxy.html#balancerpersist On Wed, Nov 6, 2013 at 3:44 PM, Jim Jagielski j...@jagunet.com wrote: Is BalancerPersist Off or On? Those .shm files should only stick around if we want to persist state across restarts. On Nov 6, 2013, at 8:39 AM, Thomas Eckert thomas.r.w.eck...@gmail.com wrote: As of late I'm seeing a lot of AH01179: balancer slotmem_create failed error messages which prevent apache2 from starting. I do have DefaultRuntimeDir /var/run/apache2 set. For some reasons there appear to be left-over .shm files in the DefaultRunTimeDir between stop-starts/restarts which then get picked up by mod_slotmem when mod_proxy asks it for shared memory. Unfortunately, those .shm files sometimes have the wrong size and get rejected by the mod_slotmem code due to size mismatch. To me it looks like this situation suffers from the same issue as reported in https://issues.apache.org/bugzilla/show_bug.cgi?id=55449 though I only have one user (nobody) for all the worker processes. I get the systems back up and running by deleting all .shm files in the DefaultRunTimeDir between stop-starts/restarts but this seems fragile to me. Another workaround, as crude as it is, seems to be disabling the reusing of existing shared memory segments by setting fbased = 0; in modules/slotmem/mod_slotmem_shm.c in slotmem_create(). Neither of those two appraoches seems right to me. I do need at least a temporary workaround since this is causing major havoc.
Re: error log providers, multiple vhosts, mod_syslog
On Tue, Oct 29, 2013 at 7:04 AM, Jeff Trawick traw...@gmail.com wrote: On Tue, Oct 29, 2013 at 5:30 AM, Jan Kaluža jkal...@redhat.com wrote: On 10/25/2013 03:37 PM, Jeff Trawick wrote: I'm hoping to get back to this discussion soon. I also have a 2.4.x patch I've played with that is roughly in sync with trunk (though syslog logging support isn't a provider in the 2.4.x version). Does your patch fix stderr logging? I wanted to write proof of concept logger as described by Rüdiger below, but I didn't manage to find a time for it recently :(. If you have working solution for that, I wouldn't waste my time :). No, I just have a backport to 2.4.x with accommodation for syslog. What are the thoughts around handling stderr? In some cases it is just junk if not wrapped in a proper message (i.e., there can be a requirement that error log be completely parseable and/or a requirement that stderr has timestamps or other info). But it seems to require a thread of execution to implement that in order to avoid blocking the writer. (Recently I encountered a situation where a third-party module called some library during httpd init that wrote an initialization message directly to stderr, and the message was stuck in the stdio buffer and forked into every child process for later, multiple appearances :) ) I guess an error log provider could be given the opportunity to route stderr wherever it wants, but that doesn't handle the existing suckage of random, un-timestamped stuff in the log for normal configurations. I guess you could have mod_stderr that may or may not be enabled if you wanted stderr handled more cleanly (groan), whether or not you had a provider for ap_log calls. Thanks, Jan Kaluza On Thu, Oct 17, 2013 at 8:33 AM, Plüm, Rüdiger, Vodafone Group ruediger.pl...@vodafone.com mailto:ruediger.pl...@vodafone.com wrote: -Original Message- From: Jan Kaluža Sent: Donnerstag, 17. Oktober 2013 13:21 To: dev@httpd.apache.org mailto:dev@httpd.apache.org Subject: Re: error log providers, multiple vhosts, mod_syslog There's another problem with log providers and vhosts and I think I have no idea how to fix it without doing dirty hacks... The problem is with ap_open_logs function, which does following: 1. Main server log is opened (open_error_log()). If this log uses error log provider, s_main-error_log is set to NULL. 2. When there is no s_main-error_log, stderr is redirected to /dev/null. Hmm. This points out another issue when using an error log provider for the main server log: We lose everything that the server or other programs like CGI-scripts write to the stderr FD as it is simply written to /dev/null. Don't we need to have a separate process in this case that like a piped logger reads from the reading end of the stderr pipe and writes it via ap_server_conf-errorlog_provider-writer to the log? 3. Error logs for vhosts are opened (another open_error_log()). If there is some problem when opening these logs, any ap_log_error() call is sent to /dev/null. Wouldn't it try to call s-errorlog_provider-writer in line 1196 and Segfault if s-errorlog_provider is NULL because of some bad classic configuration that simply failed? Regards Rüdiger -- Born in Roswell... married an alien... http://emptyhammock.com/ -- Born in Roswell... married an alien... http://emptyhammock.com/ -- Born in Roswell... married an alien... http://emptyhammock.com/
apache sql module with suexec
Hello,
I'm trying to write a module which would work with httpd.worker. It will
per-request fetch row from mysql returning documentroot, servername, user,
group.
How can I setuid(), setgid()?
I have fetched these user/group from DB using mod_dbd module and now want
to set using suEXEC these user/group.
apr_uid_t _uid;
apr_gid_t _gid;
apr_uid_current(_uid, _gid, r-pool);
ap_log_rerror(APLOG_MARK, APLOG_CRIT, 0, r, apt_user/group:
%d/%d, _uid, _gid);
if(setuid(500)) {
ap_log_rerror(APLOG_MARK, APLOG_CRIT, 0, r, apt_user:
%d, getuid());
}
Apache log gives:
[Wed Nov 06 10:16:42 2013] [crit] [client X] user: ton
[Wed Nov 06 10:16:42 2013] [crit] [client X] apt_user/group: 48/48
[Wed Nov 06 10:16:42 2013] [crit] [client X] apt_user: 48
[Wed Nov 06 10:16:42 2013] [crit] [client X] group: group-ton
--
Donatas
Re: mod_proxy reverse proxying and AH01179: balancer slotmem_create failed
try this: slotmem.patch Description: Binary data On Nov 6, 2013, at 9:59 AM, Thomas Eckert thomas.r.w.eck...@gmail.com wrote: It is not mentioned specifically in the configuration files, so it defaults to Off according to http://httpd.apache.org/docs/current/mod/mod_proxy.html#balancerpersist On Wed, Nov 6, 2013 at 3:44 PM, Jim Jagielski j...@jagunet.com wrote: Is BalancerPersist Off or On? Those .shm files should only stick around if we want to persist state across restarts. On Nov 6, 2013, at 8:39 AM, Thomas Eckert thomas.r.w.eck...@gmail.com wrote: As of late I'm seeing a lot of AH01179: balancer slotmem_create failed error messages which prevent apache2 from starting. I do have DefaultRuntimeDir /var/run/apache2 set. For some reasons there appear to be left-over .shm files in the DefaultRunTimeDir between stop-starts/restarts which then get picked up by mod_slotmem when mod_proxy asks it for shared memory. Unfortunately, those .shm files sometimes have the wrong size and get rejected by the mod_slotmem code due to size mismatch. To me it looks like this situation suffers from the same issue as reported in https://issues.apache.org/bugzilla/show_bug.cgi?id=55449 though I only have one user (nobody) for all the worker processes. I get the systems back up and running by deleting all .shm files in the DefaultRunTimeDir between stop-starts/restarts but this seems fragile to me. Another workaround, as crude as it is, seems to be disabling the reusing of existing shared memory segments by setting fbased = 0; in modules/slotmem/mod_slotmem_shm.c in slotmem_create(). Neither of those two appraoches seems right to me. I do need at least a temporary workaround since this is causing major havoc.
Re: error log providers, multiple vhosts, mod_syslog
On Wed, 6 Nov 2013 10:05:25 -0500 Jeff Trawick traw...@gmail.com wrote: What are the thoughts around handling stderr? In some cases it is just junk if not wrapped in a proper message (i.e., there can be a requirement that error log be completely parseable and/or a requirement that stderr has timestamps or other info). But it seems to require a thread of execution to implement that in order to avoid blocking the writer. (Recently I encountered a situation where a third-party module called some library during httpd init that wrote an initialization message directly to stderr, and the message was stuck in the stdio buffer and forked into every child process for later, multiple appearances :) ) I guess an error log provider could be given the opportunity to route stderr wherever it wants, but that doesn't handle the existing suckage of random, un-timestamped stuff in the log for normal configurations. I guess you could have mod_stderr that may or may not be enabled if you wanted stderr handled more cleanly (groan), whether or not you had a provider for ap_log calls. The windows nt event logging logic faced the same issue (and was the reason for the early _commit() call :), so stderr is shifted to a pipe to 'decorate' it into the event log queue, which would look very similar for timestamps/other annotations into a syslog provider.
