open_basedir?

Hi internals, The open_basedir ini setting has two significant problems: 1. It is a major performance hit, because it disables the realpath cache. 2. Many people think it is a security feature and use it as such. However, open_basedir is in reality a "best effort" mechanism, with known workarounds and more regularly being found. Especially when it comes to interactions with 3rd party libraries, enforcing open_basedir is simply impossible. What open_basedir tries to do must be implemented on the operating system level to work reliably (and of course such mechanisms exist, such as jails, chroot and friends). I wonder if it is feasible to drop this ini setting? Enforcing this doesn't really seem like any of PHP's business. If not, I think we need to at least a) make it clear in the documentation that this is *not* a security option and only exists to prevent "accidents" and b) update the security policy (https://wiki.php.net/security) to state that open_basedir bypasses are not security issues. I believe this has been part of Debian's security policy for some time already. Regards, Nikita