1/*
2 * Copyright (c) 2000-2006 Apple Computer, Inc. All rights reserved.
3 *
4 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
5 *
6 * This file contains Original Code and/or Modifications of Original Code
7 * as defined in and that are subject to the Apple Public Source License
8 * Version 2.0 (the 'License'). You may not use this file except in
9 * compliance with the License. The rights granted to you under the License
10 * may not be used to create, or enable the creation or redistribution of,
11 * unlawful or unlicensed copies of an Apple operating system, or to
12 * circumvent, violate, or enable the circumvention or violation of, any
13 * terms of an Apple operating system software license agreement.
14 *
15 * Please obtain a copy of the License at
16 * http://www.opensource.apple.com/apsl/ and read it before using this file.
17 *
18 * The Original Code and all software distributed under the License are
19 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
20 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
21 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
22 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
23 * Please see the License for the specific language governing rights and
24 * limitations under the License.
25 *
26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
27 */
28
29/*
30 * Indirect driver for console
31 *
32 * The purpose of this driver is to provide a device node indirection for
33 * the console device, which can be any tty class device. It does this by
34 * externalizing a global pointer "constty", which is then pointed at the
35 * console tty device.
36 *
37 * The default for this pointer is uninitialized; when it is NULL, we fall
38 * back to the "km" device, which is a tty BSD wrapper device for the
39 * Platform Expert console device. When it is non-NULL, we call through
40 * to the tty device device instead.
41 *
42 * The registration for this device node is static, and the devfs init
43 * code does not externalize a named device for it, to avoid software
44 * seeing the device and trying to open it.
45 *
46 * The upshot of this is that the console driver should not be set as your
47 * controlling tty, since you will get a reference to a device which does
48 * not have an actual device node in /dev, so its name cannot be looked up.
49 */
50#include <sys/param.h>
51#include <sys/systm.h>
52#include <sys/conf.h>
53#include <sys/ioctl.h>
54#include <sys/tty.h>
55#include <sys/proc.h>
56#include <sys/uio.h>
57
58struct tty *constty; /* current console device */
59
60/*
61 * The km driver supplied the default console device for the systems
62 * (usually a raw frame buffer driver, but potentially a serial driver).
63 */
64extern struct tty *km_tty[1];
65
66/*
67 * cdevsw[] entries for the console device driver
68 */
69int cnopen(__unused dev_t dev, int flag, int devtype, proc_t pp);
70int cnclose(__unused dev_t dev, int flag, int mode, proc_t pp);
71int cnread(__unused dev_t dev, struct uio *uio, int ioflag);
72int cnwrite(__unused dev_t dev, struct uio *uio, int ioflag);
73int cnioctl(__unused dev_t dev, u_long cmd, caddr_t addr, int flg, proc_t p);
74int cnselect(__unused dev_t dev, int flag, void * wql, proc_t p);
75
76static dev_t
77cndev(void)
78{
79 if (constty)
80 return constty->t_dev;
81 else
82 return km_tty[0]->t_dev;
83}
84
85int
86cnopen(__unused dev_t dev, int flag, int devtype, struct proc *pp)
87{
88 dev = cndev();
89 return ((*cdevsw[major(dev)].d_open)(dev, flag, devtype, pp));
90}
91
92
93int
94cnclose(__unused dev_t dev, int flag, int mode, struct proc *pp)
95{
96 dev = cndev();
97 return ((*cdevsw[major(dev)].d_close)(dev, flag, mode, pp));
98}
99
100
101int
102cnread(__unused dev_t dev, struct uio *uio, int ioflag)
103{
104 dev = cndev();
105 return ((*cdevsw[major(dev)].d_read)(dev, uio, ioflag));
106}
107
108
109int
110cnwrite(__unused dev_t dev, struct uio *uio, int ioflag)
111{
112 dev = cndev();
113 return ((*cdevsw[major(dev)].d_write)(dev, uio, ioflag));
114}
115
116
117int
118cnioctl(__unused dev_t dev, u_long cmd, caddr_t addr, int flag, struct proc *p)
119{
120 dev = cndev();
121#if 0
122 /*
123 * Superuser can always use this to wrest control of console
124 * output from the "virtual" console.
125 *
126 * XXX Unfortunately, this code doesn't do what the author thougt
127 * XXX it did; use of the console device, a TIOCCONS would always
128 * XXX disassociate the console from a virtual terminal and send
129 * XXX it back to the fake tty.
130 */
131 if ((unsigned) cmd == TIOCCONS && constty) {
132 int error = proc_suser(p);
133 if (!error) {
134 constty = NULL;
135 }
136 return(error);
137 }
138#endif /* 0 */
139
140 return ((*cdevsw[major(dev)].d_ioctl)(dev, cmd, addr, flag, p));
141}
142
143
144int
145cnselect(__unused dev_t dev, int flag, void *wql, struct proc *p)
146{
147 dev = cndev();
148 return ((*cdevsw[major(dev)].d_select)(dev, flag, wql, p));
149}
150