test1.c

《UNIX进程间通信》中的代码

	if (prio != 1)
		err_quit("mq_receive returned prio %d, expected 1", prio);
		/* check nonblockiing receive */
	if ( (rc = mq_receive(mqd, msg, info.mq_msgsize, &prio)) == 0 ||
		errno != EAGAIN)
		err_sys("mq_receive returned %d, expected EAGAIN", rc);

		/* fill queue then close it */
	Mq_send(mqd, msg1, 1, 1);
	Mq_send(mqd, msg4, 4, 4);
	Mq_send(mqd, msg2, 2, 2);
	Mq_send(mqd, msg3, 3, 3);
		/* first check nonblocking send */
	if ( (rc = mq_send(mqd, msg5, 5, 5)) == 0 || errno != EAGAIN)
		err_sys("mq_send returned %d, expected EAGAIN", rc);
	Mq_close(mqd);

		/* open existing queue and read */
	mqd = Mq_open(argv[1], O_RDWR);
	if ( (rc = Mq_receive(mqd, msg, info.mq_msgsize, &prio)) != 4)
		err_quit("mq_receive returned %d, expected 4", rc);
	if (prio != 4)
		err_quit("mq_receive returned prio %d, expected 4", prio);
		/* now set nonblocking with mq_setattr */
	attr.mq_flags = O_NONBLOCK;
	Mq_setattr(mqd, &attr, &info);
	if (info.mq_maxmsg != 4 || info.mq_msgsize != 7 ||
		info.mq_flags != 0 || info.mq_curmsgs != 3)
		err_quit("3: maxmsg = %ld, msgsize = %ld, flags = %ld, curmsgs = %ld\n",
		   		 info.mq_maxmsg, info.mq_msgsize,
				 info.mq_flags, info.mq_curmsgs);
	Mq_getattr(mqd, &info);
	if (info.mq_maxmsg != 4 || info.mq_msgsize != 7 ||
		info.mq_flags != O_NONBLOCK || info.mq_curmsgs != 3)
		err_quit("4: maxmsg = %ld, msgsize = %ld, flags = %ld, curmsgs = %ld\n",
		   		 info.mq_maxmsg, info.mq_msgsize,
				 info.mq_flags, info.mq_curmsgs);
	if ( (rc = Mq_receive(mqd, msg, info.mq_msgsize, &prio)) != 3)
		err_quit("mq_receive returned %d, expected 3", rc);
	if (prio != 3)
		err_quit("mq_receive returned prio %d, expected 3", prio);
	if ( (rc = Mq_receive(mqd, msg, info.mq_msgsize, &prio)) != 2)
		err_quit("mq_receive returned %d, expected 2", rc);
	if (prio != 2)
		err_quit("mq_receive returned prio %d, expected 2", prio);
	if ( (rc = Mq_receive(mqd, msg, info.mq_msgsize, &prio)) != 1)
		err_quit("mq_receive returned %d, expected 1", rc);
	if (prio != 1)
		err_quit("mq_receive returned prio %d, expected 1", prio);
		/* check nonblocking receive */
	if ( (rc = mq_receive(mqd, msg, info.mq_msgsize, &prio)) == 0 ||
		errno != EAGAIN)
		err_sys("mq_receive returned %d, expected EAGAIN", rc);

		/* now clear nonblocking with mq_setattr */
	attr.mq_flags = 0;
	Mq_setattr(mqd, &attr, &info);
	if (info.mq_maxmsg != 4 || info.mq_msgsize != 7 ||
		info.mq_flags != O_NONBLOCK || info.mq_curmsgs != 0)
		err_quit("5: maxmsg = %ld, msgsize = %ld, flags = %ld, curmsgs = %ld\n",
		   		 info.mq_maxmsg, info.mq_msgsize,
				 info.mq_flags, info.mq_curmsgs);
	Mq_getattr(mqd, &info);
	if (info.mq_maxmsg != 4 || info.mq_msgsize != 7 ||
		info.mq_flags != 0 || info.mq_curmsgs != 0)
		err_quit("6: maxmsg = %ld, msgsize = %ld, flags = %ld, curmsgs = %ld\n",
		   		 info.mq_maxmsg, info.mq_msgsize,
				 info.mq_flags, info.mq_curmsgs);
#ifdef	notdef
		/* queue is empty; check that mq_receive is interruptable */
	Signal(SIGALRM, sig_alrm);
	blocked = 1;
	alarm(4);
	if ( (rc = mq_receive(mqd, msg, info.mq_msgsize, &prio)) == 0 ||
		errno != EINTR)
		err_sys("mq_receive returned %d, expected EINTR", rc);
	alarm(0);
	printf("mq_receive interrupted, as expected\n");

		/* fill queue */
	Mq_send(mqd, msg1, 1, 1);
	Mq_send(mqd, msg2, 2, 2);
	Mq_send(mqd, msg3, 3, 3);
	Mq_send(mqd, msg4, 4, 4);
	Mq_getattr(mqd, &info);
	if (info.mq_maxmsg != 4 || info.mq_msgsize != 7 ||
		info.mq_flags != 0 || info.mq_curmsgs != 4)
		err_quit("7: maxmsg = %ld, msgsize = %ld, flags = %ld, curmsgs = %ld\n",
		   		 info.mq_maxmsg, info.mq_msgsize,
				 info.mq_flags, info.mq_curmsgs);
		/* queue is full; check that mq_send is interruptable */
	Signal(SIGALRM, sig_alrm);
	blocked = 1;
	alarm(4);
printf("about to call mq_send\n");
	if ( (rc = mq_send(mqd, msg5, 5, 5)) == 0 || errno != EINTR)
		err_sys("mq_send returned %d, expected EINTR", rc);
	alarm(0);
	printf("mq_send interrupted, as expected\n");
#endif

		/* queue is empty, register for notification */
	sigev.sigev_notify = SIGEV_SIGNAL;
	sigev.sigev_signo = SIGUSR1;
	Signal(SIGUSR1, sig_usr1);
	Mq_notify(mqd, &sigev);
		/* verify we cannot register twice */
	if ( (rc = mq_notify(mqd, &sigev)) == 0 || errno != EBUSY)
		err_sys("mq_notify returned %d, expected EBUSY", rc);
		/* now unregister, then reregister */
	Mq_notify(mqd, NULL);
	Mq_notify(mqd, &sigev);
		/* verify we cannot register twice */
	if ( (rc = mq_notify(mqd, &sigev)) == 0 || errno != EBUSY)
		err_sys("mq_notify returned %d, expected EBUSY", rc);

		/* make certain child cannot register if we are registered */
	if ( (childpid = Fork()) == 0) {
		if ( (rc = mq_notify(mqd, &sigev)) == 0 || errno != EBUSY)
			err_sys("mq_notify returned %d, expected EBUSY", rc);
		exit(0);
	}
	Waitpid(childpid, NULL, 0);

		/* send a message and verify SIGUSR1 is delivered */
	sigusr1 = 0;
	Mq_send(mqd, msg5, 5, 5);
	sleep(1);
	if (sigusr1 != 1)
		err_quit("sigusr1 = %d, expected 1", sigusr1);
	if ( (rc = Mq_receive(mqd, msg, info.mq_msgsize, &prio)) != 5)
		err_quit("mq_receive returned %d, expected 5", rc);
	if (prio != 5)
		err_quit("mq_receive returned prio %d, expected 5", prio);

		/* send another and make certain another signal is not sent */
	Mq_send(mqd, msg2, 2, 2);
	sleep(1);
	if (sigusr1 != 1)
		err_quit("sigusr1 = %d, expected 1", sigusr1);
	if ( (rc = Mq_receive(mqd, msg, info.mq_msgsize, &prio)) != 2)
		err_quit("mq_receive returned %d, expected 2", rc);
	if (prio != 2)
		err_quit("mq_receive returned prio %d, expected 2", prio);

		/* reregister */
	Mq_notify(mqd, &sigev);
	if ( (childpid = Fork()) == 0) {
			/* child calls mq_receive, which prevents notification */
		if ( (rc = Mq_receive(mqd, msg, info.mq_msgsize, &prio)) != 6)
			err_quit("mq_receive returned %d, expected 6", rc);
		if (prio != 6)
			err_quit("mq_receive returned prio %d, expected 6", prio);
		exit(0);
	}
	sleep(2);		/* let child block in mq_receive() */
	Mq_send(mqd, msg6, 6, 6);
	Waitpid(childpid, NULL, 0);
	if (sigusr1 != 1)
		err_quit("sigusr1 = %d, expected 1", sigusr1);

		/* make certain parent can send messages to child, and vice versa */
	if ( (childpid = Fork()) == 0) {
		sleep(2);		/* let parent send two messages */
		if ( (rc = Mq_receive(mqd, msg, info.mq_msgsize, &prio)) != 3)
			err_quit("mq_receive returned %d, expected 3", rc);
		if (prio != 3)
			err_quit("mq_receive returned prio %d, expected 3", prio);
		if ( (rc = Mq_receive(mqd, msg, info.mq_msgsize, &prio)) != 1)
			err_quit("mq_receive returned %d, expected 1", rc);
		if (prio != 1)
			err_quit("mq_receive returned prio %d, expected 1", prio);
		exit(0);
	}
	Mq_send(mqd, msg1, 1, 1);
	Mq_send(mqd, msg3, 3, 3);
	Waitpid(childpid, NULL, 0);
	Mq_getattr(mqd, &info);
	if (info.mq_maxmsg != 4 || info.mq_msgsize != 7 ||
		info.mq_flags != 0 || info.mq_curmsgs != 0)
		err_quit("8: maxmsg = %ld, msgsize = %ld, flags = %ld, curmsgs = %ld\n",
		   		 info.mq_maxmsg, info.mq_msgsize,
				 info.mq_flags, info.mq_curmsgs);

	if ( (childpid = Fork()) == 0) {
		Mq_send(mqd, msg3, 3, 3);
		Mq_send(mqd, msg5, 5, 5);
		Mq_send(mqd, msg1, 1, 1);
		exit(0);
	}
	sleep(2);		/* let child send 3 messages */
	if ( (rc = Mq_receive(mqd, msg, info.mq_msgsize, &prio)) != 5)
		err_quit("mq_receive returned %d, expected 5", rc);
	if (prio != 5)
		err_quit("mq_receive returned prio %d, expected 5", prio);
	if ( (rc = Mq_receive(mqd, msg, info.mq_msgsize, &prio)) != 3)
		err_quit("mq_receive returned %d, expected 3", rc);
	if (prio != 3)
		err_quit("mq_receive returned prio %d, expected 3", prio);
	if ( (rc = Mq_receive(mqd, msg, info.mq_msgsize, &prio)) != 1)
		err_quit("mq_receive returned %d, expected 1", rc);
	if (prio != 1)
		err_quit("mq_receive returned prio %d, expected 1", prio);
	Waitpid(childpid, NULL, 0);
	Mq_getattr(mqd, &info);
	if (info.mq_maxmsg != 4 || info.mq_msgsize != 7 ||
		info.mq_flags != 0 || info.mq_curmsgs != 0)
		err_quit("9: maxmsg = %ld, msgsize = %ld, flags = %ld, curmsgs = %ld\n",
		   		 info.mq_maxmsg, info.mq_msgsize,
				 info.mq_flags, info.mq_curmsgs);

	printf("done\n");
	exit(0);
}

static void
sig_usr1(int signo)
{
	sigusr1++;
	return;
}

static void
sig_alrm(int signo)
{
	printf("SIGALRM caught\n");
	return;
}