listening to /dev/audit in a pthread program

paul moore paulmoore100 at hotmail.com
Fri Apr 20 22:35:34 UTC 2007


I have an test app that quite happily does an audit_set_pid and then sits
there reading /dev/audit.
 
It works fine if its in the lead thread. But when I run the same code in my
real app it runs in a different thread. No matter what PID I pass to the
audit subsystem it complains that nobody is listening
 
I did audit_set_pid(....getpid...) - no (passes the pid of the manager
thread)
I did audit_set_pid(....gettid...) - no (passes the pid of the LWP)
 
(I dont really mean I did gettid - I did syscall(_NR_gettid))

I can see in the complaint message that I have given it the pid I intended
to. 
I can see in gdb that my LWP id is the same as the one I send to the audit
subsystem - ie gettid worked.
 
Is this a known issue?

Heres the code snippet

void listen()
{

    // register for events
  	pid_t mytid = (pid_t)syscall(__NR_gettid);
      int res = audit_set_pid(m_auditFD, mytid, WAIT_YES);


    res = audit_set_enabled(m_auditFD, 1);
    assert(res >= 0);

    static audit_reply reply;

    while (true)
    {
        res = audit_get_reply(m_auditFD, &reply, GET_REPLY_BLOCKING, 0);
        if (res < 0)
	{
		printf("exit audit %d %d\n", res, errno);
            break;
		}
        printf("got event %.*s\n", reply.msg.nlh.nlmsg_len, reply.msg.data);

    }
}

The thread sits waiting on the audit_get_reply call, so the FD is open




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