I configured postfix on my box to call a php script on incoming e-mails, using virtual aliases. The script is being called, but it runs as "nobody" and thus I can't send signals to another program from my script that runs as a real user.
I found the setting default_privs and set it to the user that runs the program I want to signal, and this works, but that still allows me to signal only programs of that one user.
How can I solve this? I guess putting root in default_privs and having the called script su into the appropriate user account would be a stupid move, but what alternatives are there?