Hello all
I want to create a process in C that has to answer php requests.
I choose to communicate with named pipes between php and my process. Php is UID 33 and GID 33. When I launch my process I can launch it either with my UID (1000) or root. I must say that I added myself in the GID 33 group of php/apache. (groups command tells its done)
To communicate between PHP and the process I want to use SIGUSR1 to tell the process that there is a request from php so the process won't wait for php request
I noticed that in php when I call posix_kill with SIGUSR1 it says that I don't have permissions. So I added posix_setuid(1000) in php but it doesn't help : no permission.
Then I had the idea to posix_setuid(33) in the process when launched as root but it doesn't help neither : no permission.
Would some one explain me what's wrong ?
Thanks !

Welcome to Linux Questions. From reading your post, I don't think that this is a security issue, but one of programming. Specifically, what are the suitable methods for IPC (Inter Process Communication). Off hand, my initial guess is that you are running into the permissions limitations of setuid, in which executable functions are normally prohibited from script (non compiled) applications. Consequently this may not be the best approach.

I have used the report function and given the recommendation that this thread be moved to the programming forum to give it the attention it deserves.

Moved: This thread is more suitable in the Programming forum and has been moved accordingly to help your thread/question get the exposure it deserves.