linux-kernel - question on tty open and close

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Message-Id: <200703281338.29250.oliver@neukum.org>
Date:	Wed, 28 Mar 2007 13:38:29 +0200
From:	Oliver Neukum <oliver@...kum.org>
To:	linux-kernel@...r.kernel.org
Subject: question on tty open and close

Hi,

in tty_io.c::tty_open():

	if (!retval) {
		if (tty->driver->open)
			retval = tty->driver->open(tty, filp);
		else
			retval = -ENODEV;
	}
	filp->f_flags = saved_flags;

	if (!retval && test_bit(TTY_EXCLUSIVE, &tty->flags) && !capable(CAP_SYS_ADMIN))
		retval = -EBUSY;

	if (retval) {
#ifdef TTY_DEBUG_HANGUP
		printk(KERN_DEBUG "error %d in opening %s...", retval,
		       tty->name);
#endif
		release_dev(filp);

We find that a failure in open() leads to release_dev() being called.
release_dev() calls close():

	if (tty->driver->close)
		tty->driver->close(tty, filp);

So we have a file that's closed although open() never succeeded?
What's the reason for that?

	Regards
		Oliver
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