4 * Copyright (c) 1982, 1986, 1991, 1993
5 * The Regents of the University of California. All rights reserved.
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. All advertising materials mentioning features or use of this software
16 * must display the following acknowledgement:
17 * This product includes software developed by the University of
18 * California, Berkeley and its contributors.
19 * 4. Neither the name of the University nor the names of its contributors
20 * may be used to endorse or promote products derived from this software
21 * without specific prior written permission.
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 * @(#)tty_tty.c 8.2 (Berkeley) 9/23/93
36 * $FreeBSD: src/sys/kern/tty_tty.c,v 1.30 1999/09/25 18:24:24 phk Exp $
37 * $DragonFly: src/sys/kern/tty_tty.c,v 1.19 2007/07/03 17:22:14 dillon Exp $
41 * Indirect driver for controlling tty.
44 #include <sys/param.h>
45 #include <sys/systm.h>
47 #include <sys/device.h>
49 #include <sys/fcntl.h>
51 #include <sys/ttycom.h>
52 #include <sys/vnode.h>
53 #include <sys/kernel.h>
54 #include <sys/poll.h> /* XXX: poll args used in KQ filters */
55 #include <sys/event.h>
57 static d_open_t cttyopen;
58 static d_close_t cttyclose;
59 static d_read_t cttyread;
60 static d_write_t cttywrite;
61 static d_ioctl_t cttyioctl;
62 static d_kqfilter_t cttykqfilter;
64 static void cttyfilt_detach(struct knote *);
65 static int cttyfilt_read(struct knote *, long);
66 static int cttyfilt_write(struct knote *, long);
69 static struct dev_ops ctty_ops = {
70 { "ctty", CDEV_MAJOR, D_TTY },
76 .d_kqfilter = cttykqfilter
79 #define cttyvp(p) ((p)->p_flag & P_CONTROLT ? (p)->p_session->s_ttyvp : NULL)
82 * This opens /dev/tty. Because multiple opens of /dev/tty only
83 * generate a single open to the actual tty, the file modes are
84 * locked to FREAD|FWRITE.
87 cttyopen(struct dev_open_args *ap)
89 struct proc *p = curproc;
95 if ((ttyvp = cttyvp(p)) == NULL)
97 if (ttyvp->v_flag & VCTTYISOPEN)
101 * Messy interlock, don't let the vnode go away while we try to
102 * lock it and check for race after we might have blocked.
105 vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY);
106 if (ttyvp != cttyvp(p) || (ttyvp->v_flag & VCTTYISOPEN)) {
107 kprintf("Warning: cttyopen: race avoided\n");
112 vsetflags(ttyvp, VCTTYISOPEN);
113 error = VOP_OPEN(ttyvp, FREAD|FWRITE, ap->a_cred, NULL);
115 vclrflags(ttyvp, VCTTYISOPEN);
122 * This closes /dev/tty. Because multiple opens of /dev/tty only
123 * generate a single open to the actual tty, the file modes are
124 * locked to FREAD|FWRITE.
127 cttyclose(struct dev_close_args *ap)
129 struct proc *p = curproc;
136 * The tty may have been TIOCNOTTY'd, don't return an
137 * error on close. We just have nothing to do.
139 if ((ttyvp = cttyvp(p)) == NULL)
141 if (ttyvp->v_flag & VCTTYISOPEN) {
143 * Avoid a nasty race if we block while getting the lock.
146 error = vn_lock(ttyvp, LK_EXCLUSIVE | LK_RETRY);
151 if (ttyvp != cttyvp(p) || (ttyvp->v_flag & VCTTYISOPEN) == 0) {
152 kprintf("Warning: cttyclose: race avoided\n");
157 vclrflags(ttyvp, VCTTYISOPEN);
158 error = VOP_CLOSE(ttyvp, FREAD|FWRITE);
168 * Read from the controlling terminal (/dev/tty). The tty is refed as
169 * of the cttyvp(), but the ref can get ripped out from under us if
170 * the controlling terminal is revoked while we are blocked on the lock,
171 * so use vget() instead of vn_lock().
174 cttyread(struct dev_read_args *ap)
176 struct proc *p = curproc;
184 if ((error = vget(ttyvp, LK_EXCLUSIVE | LK_RETRY)) == 0) {
185 error = VOP_READ(ttyvp, ap->a_uio, ap->a_ioflag, NOCRED);
192 * Read from the controlling terminal (/dev/tty). The tty is refed as
193 * of the cttyvp(), but the ref can get ripped out from under us if
194 * the controlling terminal is revoked while we are blocked on the lock,
195 * so use vget() instead of vn_lock().
198 cttywrite(struct dev_write_args *ap)
200 struct proc *p = curproc;
208 if ((error = vget(ttyvp, LK_EXCLUSIVE | LK_RETRY)) == 0) {
209 error = VOP_WRITE(ttyvp, ap->a_uio, ap->a_ioflag, NOCRED);
217 cttyioctl(struct dev_ioctl_args *ap)
220 struct proc *p = curproc;
223 lwkt_gettoken(&proc_token);
226 lwkt_reltoken(&proc_token);
230 * Don't allow controlling tty to be set to the controlling tty
231 * (infinite recursion).
233 if (ap->a_cmd == TIOCSCTTY) {
234 lwkt_reltoken(&proc_token);
237 if (ap->a_cmd == TIOCNOTTY) {
238 if (!SESS_LEADER(p)) {
239 p->p_flag &= ~P_CONTROLT;
240 lwkt_reltoken(&proc_token);
243 lwkt_reltoken(&proc_token);
247 lwkt_reltoken(&proc_token);
249 return (VOP_IOCTL(ttyvp, ap->a_cmd, ap->a_data, ap->a_fflag,
250 ap->a_cred, ap->a_sysmsg));
253 static struct filterops cttyfiltops_read =
254 { FILTEROP_ISFD, NULL, cttyfilt_detach, cttyfilt_read };
255 static struct filterops cttyfiltops_write =
256 { FILTEROP_ISFD, NULL, cttyfilt_detach, cttyfilt_write };
259 cttykqfilter(struct dev_kqfilter_args *ap)
261 cdev_t dev = ap->a_head.a_dev;
262 struct proc *p = curproc;
263 struct knote *kn = ap->a_kn;
270 return (VOP_KQFILTER(ttyvp, kn));
274 switch (kn->kn_filter) {
276 kn->kn_fop = &cttyfiltops_read;
277 kn->kn_hook = (caddr_t)dev;
280 kn->kn_fop = &cttyfiltops_write;
281 kn->kn_hook = (caddr_t)dev;
284 ap->a_result = EOPNOTSUPP;
292 cttyfilt_detach(struct knote *kn) {}
295 cttyfilt_read(struct knote *kn, long hint)
297 cdev_t dev = (cdev_t)kn->kn_hook;
299 if (seltrue(dev, POLLIN | POLLRDNORM))
306 cttyfilt_write(struct knote *kn, long hint)
308 cdev_t dev = (cdev_t)kn->kn_hook;
310 if (seltrue(dev, POLLOUT | POLLWRNORM))
317 ctty_drvinit(void *unused __unused)
319 make_dev(&ctty_ops, 0, 0, 0, 0666, "tty");
322 SYSINIT(cttydev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,ctty_drvinit,NULL)