/*-
* Copyright (c) 2008 Ed Schouten <ed@FreeBSD.org>
* All rights reserved.
*
* Portions of this software were developed under sponsorship from Snow
* B.V., the Netherlands.
*
* 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/conf.h>
#include <sys/eventhandler.h>
#include <sys/fcntl.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/sysctl.h>
#include <sys/systm.h>
#include <sys/tty.h>
/*
* This driver implements a BSD-style compatibility naming scheme for
* the pts(4) driver. We just call into pts(4) to create the actual PTY.
* To make sure we don't use the same PTY multiple times, we abuse
* si_drv1 inside the cdev to mark whether the PTY is in use.
*/
static unsigned int pty_warningcnt = 10;
SYSCTL_UINT(_kern, OID_AUTO, tty_pty_warningcnt, CTLFLAG_RW,
&pty_warningcnt, 0,
"Warnings that will be triggered upon PTY allocation");
static int
ptydev_fdopen(struct cdev *dev, int fflags, struct thread *td, struct file *fp)
{
int u, error;
char name[] = "ttyXX";
if (!atomic_cmpset_ptr((uintptr_t *)&dev->si_drv1, 0, 1))
return (EBUSY);
/* Generate device name and create PTY. */
u = dev2unit(dev);
name[3] = u >> 8;
name[4] = u;
error = pts_alloc_external(fflags & (FREAD|FWRITE), td, fp, dev, name);
if (error != 0) {
destroy_dev_sched(dev);
return (error);
}
/* Raise a warning when a legacy PTY has been allocated. */
if (pty_warningcnt > 0) {
pty_warningcnt--;
printf("pid %d (%s) is using legacy pty devices%s\n",
td->td_proc->p_pid, td->td_name,
pty_warningcnt ? "" : " - not logging anymore");
}
return (0);
}
static struct cdevsw ptydev_cdevsw = {
.d_version = D_VERSION,
.d_fdopen = ptydev_fdopen,
.d_name = "ptydev",
};
static void
pty_clone(void *arg, struct ucred *cr, char *name, int namelen,
struct cdev **dev)
{
int u;
/* Cloning is already satisfied. */
if (*dev != NULL)
return;
/* Only catch /dev/ptyXX. */
if (namelen != 5 || bcmp(name, "pty", 3) != 0)
return;
/* Only catch /dev/pty[l-sL-S]X. */
if (!(name[3] >= 'l' && name[3] <= 's') &&
!(name[3] >= 'L' && name[3] <= 'S'))
return;
/* Only catch /dev/pty[l-sL-S][0-9a-v]. */
if (!(name[4] >= '0' && name[4] <= '9') &&
!(name[4] >= 'a' && name[4] <= 'v'))
return;
/* Create the controller device node. */
u = (unsigned int)name[3] << 8 | name[4];
*dev = make_dev_credf(MAKEDEV_REF, &ptydev_cdevsw, u,
NULL, UID_ROOT, GID_WHEEL, 0666, name);
}
static void
pty_init(void *unused)
{
EVENTHANDLER_REGISTER(dev_clone, pty_clone, 0, 1000);
}
SYSINIT(pty, SI_SUB_DRIVERS, SI_ORDER_MIDDLE, pty_init, NULL);
