Joseph Salisbury <joseph.salisb...@canonical.com> writes:
> On 02/05/2016 02:59 PM, Rainer Weikusat wrote:
[recvmsg w/o iovecs returning ENOTSUP for CMSG requests]
>> Funny little problem :-). The code using the interruptible lock cleared
>> err as side effect hence the
>>
>> out:
>> return copied ? : err;
>>
>> at the end of unix_stream_read_generic didn't return the -ENOTSUP put
>> into err at the start of the function if copied was zero after the loop
>> because the size of the passed data buffer was zero.
There are more problems wrt handling control-message only reads in this
code. In particular, changing the test program as follows:
if (fork() == 0) {
sleep(1);
send(socket_fd[client], msg, sizeof msg, MSG_DONTWAIT | MSG_NOSIGNAL);
_exit(0);
}
makes the recvmsg fail with EAGAIN and judging from the code (I didn't
test this yet), it will return without an error but also without
credentials if the
err = -EAGAIN
if (!timeo)
break;
is changed to
if (!timeo) {
err = -EAGAIN;
break
}
because the following
mutex_lock(&u->readlock);
continue;
will cause the
do {
} while (size)
loop condition to be evaluated and since size is 0 (AIUI), the loop will
terminate immediately.
