I have been running roundcube successfully for years until yum update updated my server to PHP 5.1.17.
Now it works for about an hour and suddenly every time I try to log in I get
Invalid request! No data was saved.
If I restart apache using graceful, it fixes it.. If I do a full restart of apache I get the above error until I do a graceful restart.
The error log shows
session_write_close(): Failed to write session data (user). Please verify that the current setting of session.save_path is correct
This happens on multiple versions of roundcube including the one that I just downloaded yesterday.
There's a bug in suhosin + PHP 5.4. See this thread http://lists.roundcube.net/pipermail/dev/2013-May/022511.html
I just now read that article and couldn't find any references to suhosin. But just to see if suhosin was my problem, I removed /etc/php.d/suhosin.ini and restarted my webserver and still have the same problem
http://lists.roundcube.net/pipermail/dev/2013-May/022529.html I'm not sure it possible to fix this by only disabling suhosin.
You were right on about the problem being suhosin. And simply removing suhosin.ini from /etc/php.d and all references to it in php.ini didn't help, but I did find the answer. So for anyone else reading this thread, here is the fix..
Start by finding out which RPM has suhosin by running
rpm -qa | grep suhosin
Then just do an rpm -e followed by the packages revealed in the above step. Problem Solved!!
Suhosin with php 5.4 causes more problems than just those in roundcube. Many websites showed errors writing session vars and have now been fixed by simply removing the RPM. I hope this helps people with this problem.