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freebsd/sys/kern/tty_tty.c
Poul-Henning Kamp 70cd771337 The present defaults for the open and close for device drivers which
provide no methods does not make any sense, and is not used by any
driver.

It is a pretty hard to come up with even a theoretical concept of
a device driver which would always fail open and close with ENODEV.

Change the defaults to be nullopen() and nullclose() which simply
does nothing.

Remove explicit initializations to these from the drivers which
already used them.
2003-09-27 12:01:01 +00:00

81 lines
2.3 KiB
C

/*-
* Copyright (c) 2003 Poul-Henning Kamp. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/conf.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/vnode.h>
static d_open_t cttyopen;
#define CDEV_MAJOR 1
static struct cdevsw ctty_cdevsw = {
.d_open = cttyopen,
.d_name = "ctty",
.d_maj = CDEV_MAJOR,
.d_flags = D_TTY,
};
static dev_t ctty;
static int
cttyopen(dev_t dev, int flag, int mode, struct thread *td)
{
return (ENXIO);
}
static void
ctty_clone(void *arg, char *name, int namelen, dev_t *dev)
{
if (*dev != NODEV)
return;
if (strcmp(name, "tty"))
return;
if (!(curthread->td_proc->p_flag & P_CONTROLT))
*dev = ctty;
else if (curthread->td_proc->p_session->s_ttyvp == NULL)
*dev = ctty;
else
*dev = curthread->td_proc->p_session->s_ttyvp->v_rdev;
}
static void
ctty_drvinit(void *unused)
{
EVENTHANDLER_REGISTER(dev_clone, ctty_clone, 0, 1000);
ctty = make_dev(&ctty_cdevsw, 0, 0, 0, 0666, "ctty");
}
SYSINIT(cttydev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,ctty_drvinit,NULL)