Getting the full path of a running PID with C/C++ without using the system function (Linux)

Question

So I want to be able to get the full path of a running process (which I have the process ID for) without using any commands on the command line. Anyone has any ideas on how to do this?

I do have the PID, is there any function that by passing the PID can return the full path of that process as a char *?

Answer 1

Use readlink("/proc/<pid>/exe", buf, bufsize) to get the path to <pid>'s executable. This works on Linux, provided procfs is available (it usually is).

Example usage:

int get_exe_for_pid(pid_t pid, char *buf, size_t bufsize) {
    char path[32];
    sprintf(path, "/proc/%d/exe", pid);
    return readlink(path, buf, bufsize);
}

Returns -1 on failure and sets errno.