Thread

I have two sites using MSM.

All was well until today. Now, when I submit a newly created entry or edited entry, or try to submit changes to a template, I’m left with a blank white screen (View source shows nothing either).

It’s not all bad though because despite this, the changes I make are saved and the site reflects the changes and functions properly.

The client isn’t going to appreciate this too much though!

It’s hard to pinpoint what may have triggered this, but I did create a new channel and channel field group today, and assigned one to the other. I then deleted both. This may have nothing to do with the problem, but my gut instinct tells me otherwise. I’ve been poking around the database and can’t see anything obvious.

Because this is a CP issue and involves MSM I’m not 100% clear about which files need to have debug set to 1. The screen is resolutely white. Happens with both sites too.

Any help would be much appreciated.

Hrm- we really do want to get an error.  It’s possible it’s a memory error or timing out (possible, though not massively likely)- do you have access to your server logs?  Those should reveal any php errors, including memory errors (which won’t show up even with debugging on).  You should also make sure php errors show for superadmins is set in ‘Admin- System Admin- Output and Debug’ (though it sounds like it is).  And if you want to override to be sure errors are showing, if you access the CP via admin.php, open that up and look for:

$debug = 1;

Well- make sure it’s 1 temporarily.

If it’s not already showing, though- you may need to talk to your host about seeing some php error logs.

Let us know what you find.  Once we have the error, should be able to get you fixed up.

Thanks. OK. Debug is now set to 1, and Output and Debug is set to show errors to superadmins. Not seeing any error messages though.

The host has had a look at the server and comments: “I am seeing lots of entries in the security logs showing attempts to use the php function exec() which are being blocked.”

I have requested access to the php error logs, so I’ll post back when I have these.

OK- if exec is disallowed?  That could be the problem.  EE uses it to delete directories- and when you publish an entry?  It typically clears caches.  And when it clears caches, it calls that delete directory function.

If you can, see if your host will ‘unblock’ exec. 

If you want to check that cache clearing is the problem- you could open up system/ee/libraries/functions.php and around line 1056 add a return at the start of the method.  That will prevent it from running.  If no white screen after publish, we’ll know the problem is with cache clearing.  (Then remove the return- we need to be able to clear caches.)

function clear_caching($which, $sub_dir = '', $relationships=FALSE)
 {
return;

Genius!

Adding return; fixes it. So we have a cache clearing problem.

Well- that was easy.  Now to fix it!  Remove the return- we need our caching.  Then:

1.  Go in, delete the cache folder and everything in it.  Create the cache folder back via ftp.  Chmod it to 777.
2.  See if new folders get created inside it.  If page/tag/db cache folders are created, ftp into one.  Refresh- it should have files in it.  Go to ‘Tools- Data- Clear Caching’ and clear all caches.  Refresh in ftp.  Did the files get cleared out of the cache folder?  If not- it’s still broke.
3.  Delete all the folders inside the cache folder.  Create them back using ftp- chmod them to 777.  Repeat step 2. 

If it’s still not working by step 3, it’s definitely time to bring the host in and let them know you’re having trouble with a php script deleting files/folders and you suspect it’s due to permissions.  Note that the script does use exec.  See if they have any pointers.

And- let me know what happens with the above!

After step 1 the CP no longer has white screens, but they do return after a while.

In the cache folder ee creates ee_version and sql_cache folders, and files appear in them. Clearing caches via Tools, Data, Clear Caching does not clear these files.

If I repeat step 1 and carry out a few tasks in the CP, ee only creates the ee_version folder and the white screens do not occur. As soon as I visit the site proper the folder sql_cache is created and the white screens return.

Hi Ab Ovo,

Dan here, just looking to offer some help.
As Robin noted:

If it’s still not working by step 3, it’s definitely time to bring the host in and let them know you’re having trouble with a php script deleting files/folders and you suspect it’s due to permissions.  Note that the script does use exec.  See if they have any pointers.

So the next step is to contact your host and see what they have to offer. Point them to this thread and get back to us with any info they provide.

Looking forward to your reply!

Cheers,