Nonblocking stdin on telnet

[Andrei Chichak]

I am using 4.9.4 on a Coldfire 5282.

I need to do a non-blocking read on stdin in my telnet process. I have done the following, but the getchar blocks.

init.c:

	ShellInit();				/* set up the necessary queues etc */
	rtems_bsdnet_initialize_network();

	rtems_telnetd_initialize(Shell, 	/* "shell" function */
		NULL, 				/* no context necessary for echoShell */
		false,			 	/* true == remain on console */
						/* false == listen on sockets */
		RTEMS_MINIMUM_STACK_SIZE * 20, 	/* shell needs a large stack */
		SHELL_TASK_PRIO, 		/* priority */
		false 				/* false = telnetd does NOT ask for password */
						/* true = telnetd asks for password */
						/* RTEMS Shell always asks for user/passwd */
	);

shell.c:

void Shell( char *pty_name, void *cmd_arg) {
	char inCh;
	struct termios oldt, newt;
	int oldf;

	if (tcgetattr( STDIN_FILENO, &oldt)) {
		rtems_panic("bad tcgetattr");
	}

	newt = oldt;

	newt.c_lflag &= ~(ECHO | ICANON);

	if (tcsetattr (STDIN_FILENO, TCSANOW, &newt) < 0) {
		rtems_panic("bad tcsetattr");
	}

	oldf = fcntl( STDIN_FILENO, F_GETFL, 0);
	fcntl( STDIN_FILENO, F_SETFL, oldf | O_NONBLOCK);

	for (;;) {
		inCh = getchar();
		if (inCh == EOF) {
			return;
		} else {
			printf(".");
		}
	}
}

The Shell gets fired up on the telnet call, but the getchar blocks until it receives ^D (terminates telnet if it is the first character in a line), ^J, or ^M. I've tried various versions of this code, setting VMIN and VTIME to 0 and 1, but no go.

Any ideas?

Thanks,
Andrei
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