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freebsd/sys/kern/tty_tty.c
Robert Watson 6a113b3de7 Merge the dev_clone and dev_clone_cred event handlers into a single
event handler, dev_clone, which accepts a credential argument.
Implementors of the event can ignore it if they're not interested,
and most do.  This avoids having multiple event handler types and
fall-back/precedence logic in devfs.

This changes the kernel API for /dev cloning, and may affect third
party packages containg cloning kernel modules.

Requested by:	phk
MFC after:	3 days
2005-08-08 19:55:32 +00:00

81 lines
2.4 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;
static struct cdevsw ctty_cdevsw = {
.d_version = D_VERSION,
.d_open = cttyopen,
.d_name = "ctty",
.d_flags = D_TTY | D_NEEDGIANT,
};
static struct cdev *ctty;
static int
cttyopen(struct cdev *dev, int flag, int mode, struct thread *td)
{
return (ENXIO);
}
static void
ctty_clone(void *arg, struct ucred *cred, char *name, int namelen,
struct cdev **dev)
{
if (*dev != NULL)
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;
dev_ref(*dev);
}
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,ctty_drvinit,NULL)