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16 * must display the following acknowledgement:
17 * This product includes software developed by the University of
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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 $
40 * Indirect driver for controlling tty.
43 #include <sys/param.h>
44 #include <sys/systm.h>
46 #include <sys/device.h>
48 #include <sys/fcntl.h>
50 #include <sys/ttycom.h>
51 #include <sys/vnode.h>
52 #include <sys/kernel.h>
53 #include <sys/poll.h> /* XXX: poll args used in KQ filters */
54 #include <sys/event.h>
56 static d_open_t cttyopen
;
57 static d_close_t cttyclose
;
58 static d_read_t cttyread
;
59 static d_write_t cttywrite
;
60 static d_ioctl_t cttyioctl
;
61 static d_kqfilter_t cttykqfilter
;
63 static void cttyfilt_detach(struct knote
*);
64 static int cttyfilt_read(struct knote
*, long);
65 static int cttyfilt_write(struct knote
*, long);
68 static struct dev_ops ctty_ops
= {
75 .d_kqfilter
= cttykqfilter
78 #define cttyvp(p) (((p)->p_flags & P_CONTROLT) ? \
79 (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(&p
->p_token
);
224 lwkt_gettoken(&proc_token
);
227 lwkt_reltoken(&proc_token
);
228 lwkt_reltoken(&p
->p_token
);
232 * Don't allow controlling tty to be set to the controlling tty
233 * (infinite recursion).
235 if (ap
->a_cmd
== TIOCSCTTY
) {
236 lwkt_reltoken(&proc_token
);
237 lwkt_reltoken(&p
->p_token
);
240 if (ap
->a_cmd
== TIOCNOTTY
) {
241 if (!SESS_LEADER(p
)) {
242 p
->p_flags
&= ~P_CONTROLT
;
243 lwkt_reltoken(&proc_token
);
244 lwkt_reltoken(&p
->p_token
);
247 lwkt_reltoken(&proc_token
);
248 lwkt_reltoken(&p
->p_token
);
252 lwkt_reltoken(&proc_token
);
253 lwkt_reltoken(&p
->p_token
);
255 return (VOP_IOCTL(ttyvp
, ap
->a_cmd
, ap
->a_data
, ap
->a_fflag
,
256 ap
->a_cred
, ap
->a_sysmsg
));
259 static struct filterops cttyfiltops_read
=
260 { FILTEROP_ISFD
, NULL
, cttyfilt_detach
, cttyfilt_read
};
261 static struct filterops cttyfiltops_write
=
262 { FILTEROP_ISFD
, NULL
, cttyfilt_detach
, cttyfilt_write
};
265 cttykqfilter(struct dev_kqfilter_args
*ap
)
267 cdev_t dev
= ap
->a_head
.a_dev
;
268 struct proc
*p
= curproc
;
269 struct knote
*kn
= ap
->a_kn
;
276 return (VOP_KQFILTER(ttyvp
, kn
));
280 switch (kn
->kn_filter
) {
282 kn
->kn_fop
= &cttyfiltops_read
;
283 kn
->kn_hook
= (caddr_t
)dev
;
286 kn
->kn_fop
= &cttyfiltops_write
;
287 kn
->kn_hook
= (caddr_t
)dev
;
290 ap
->a_result
= EOPNOTSUPP
;
298 cttyfilt_detach(struct knote
*kn
) {}
301 cttyfilt_read(struct knote
*kn
, long hint
)
303 cdev_t dev
= (cdev_t
)kn
->kn_hook
;
305 if (seltrue(dev
, POLLIN
| POLLRDNORM
))
312 cttyfilt_write(struct knote
*kn
, long hint
)
314 cdev_t dev
= (cdev_t
)kn
->kn_hook
;
316 if (seltrue(dev
, POLLOUT
| POLLWRNORM
))
323 ctty_drvinit(void *unused __unused
)
325 make_dev(&ctty_ops
, 0, 0, 0, 0666, "tty");
328 SYSINIT(cttydev
,SI_SUB_DRIVERS
,SI_ORDER_MIDDLE
+CDEV_MAJOR
,ctty_drvinit
,NULL
)