Gnokii working in Linux command line but not in PHP system command

Gnokii working in Linu开发者_如何学运维x command line in RHEL5 but not through PHP system command. What to check?

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What is most likely happening is that SELinux is (correctly) preventing httpd from executing gnokii. httpd runs as httpd_t, gnokii is labelled as bin_t, and there's no domain transition from one to the next. Solutions include disabling SELinux completely (not recommended), allowing httpd_t to freely execute bin_t (also not recommended), and giving gnokii a new file context and creating a domain transition rule for it.

Running man httpd_selinux gives a bit more information, but in order to create a new transition rule you'll need to see the various resources linked to on the SELinux website.