2 * Copyright (c) 2008 Ed Schouten <ed@FreeBSD.org>
5 * Portions of this software were developed under sponsorship from Snow
6 * B.V., the Netherlands.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 #include <sys/cdefs.h>
31 __FBSDID("$FreeBSD$");
33 #include <sys/param.h>
35 #include <sys/eventhandler.h>
36 #include <sys/fcntl.h>
37 #include <sys/kernel.h>
39 #include <sys/sysctl.h>
40 #include <sys/syslog.h>
41 #include <sys/systm.h>
45 * This driver implements a BSD-style compatibility naming scheme for
46 * the pts(4) driver. We just call into pts(4) to create the actual PTY.
47 * To make sure we don't use the same PTY multiple times, we abuse
48 * si_drv1 inside the cdev to mark whether the PTY is in use.
51 static unsigned int pty_warningcnt = 1;
52 SYSCTL_UINT(_kern, OID_AUTO, tty_pty_warningcnt, CTLFLAG_RW,
54 "Warnings that will be triggered upon legacy PTY allocation");
57 ptydev_fdopen(struct cdev *dev, int fflags, struct thread *td, struct file *fp)
60 char name[6]; /* "ttyXX" */
62 if (!atomic_cmpset_ptr((uintptr_t *)&dev->si_drv1, 0, 1))
65 /* Generate device name and create PTY. */
66 strcpy(name, devtoname(dev));
69 error = pts_alloc_external(fflags & (FREAD|FWRITE), td, fp, dev, name);
71 destroy_dev_sched(dev);
75 /* Raise a warning when a legacy PTY has been allocated. */
76 if (pty_warningcnt > 0) {
78 log(LOG_INFO, "pid %d (%s) is using legacy pty devices%s\n",
79 td->td_proc->p_pid, td->td_name,
80 pty_warningcnt ? "" : " - not logging anymore");
86 static struct cdevsw ptydev_cdevsw = {
87 .d_version = D_VERSION,
88 .d_fdopen = ptydev_fdopen,
93 pty_clone(void *arg, struct ucred *cr, char *name, int namelen,
97 /* Cloning is already satisfied. */
101 /* Only catch /dev/ptyXX. */
102 if (namelen != 5 || bcmp(name, "pty", 3) != 0)
105 /* Only catch /dev/pty[l-sL-S]X. */
106 if (!(name[3] >= 'l' && name[3] <= 's') &&
107 !(name[3] >= 'L' && name[3] <= 'S'))
110 /* Only catch /dev/pty[l-sL-S][0-9a-v]. */
111 if (!(name[4] >= '0' && name[4] <= '9') &&
112 !(name[4] >= 'a' && name[4] <= 'v'))
115 /* Create the controller device node. */
116 *dev = make_dev_credf(MAKEDEV_REF, &ptydev_cdevsw, 0,
117 NULL, UID_ROOT, GID_WHEEL, 0666, "%s", name);
121 pty_init(void *unused)
124 EVENTHANDLER_REGISTER(dev_clone, pty_clone, 0, 1000);
127 SYSINIT(pty, SI_SUB_DRIVERS, SI_ORDER_MIDDLE, pty_init, NULL);