How to programatically get uid from pid in osx using c++?

Question

Given a pid, I want to find the owner of the process (as uid). Is there a way to get this in osx (or any unix) using C++?

Google didn\'t help. \'ps\' is able to do i

Answer 1

The source for the ps command, reveals that there is a function called get_proc_stats defined in proc/readproc.h that (among other things) returns the real user name(UID) & Effective user name(EUID) for a given pid.

You need to do install libproc-dev to get this function. and then you can do:

#include 
void printppid(pid_t pid) 
{
    proc_t process_info;
    get_proc_stats(pid, &process_info);
    printf("Real user of the process[%d] is [%s]\n", pid, process_info.ruser);
}

compile it with gcc the-file.c -lproc.

Once you have the real user name you can use getpwnam() and getgrnam() functions to get the uid.