Question

I have implemented a POSIX message queue. On the listener side, I am opening the queue like this:

mqdes = mq_open(s_mailbox_name.c_str(), O_RDONLY | O_CREAT, S_IRWXU | S_IRWXG | S_IRWXO, NULL);

On the sender side, I am opening the queue like this:

mqdes = mq_open(m_s_mailbox_name.c_str(), O_WRONLY);

The string is the same on both, lets call it /foobox

Now, when I run both the sender and receiver as the same user on the box, everything works perfectly. However If the sender and receiver are 2 different users, the receiver can not open the queue. I would think this wouldn t be a problem because I am opening the queue as 0777 above so everyone can RWX.

Is there something obvious i m doing wrong? Or is this not possible (Please don t let it be this one)

Thanks

Answer 1

Check umask.

From man mq_open: "The permissions settings are masked against the process umask."

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