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
58 struct 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 */
64 extern struct tty *km_tty[1];
65
66 /*
67 * cdevsw[] entries for the console device driver
68 */
69 int cnopen(__unused dev_t dev, int flag, int devtype, proc_t pp);
70 int cnclose(__unused dev_t dev, int flag, int mode, proc_t pp);
71 int cnread(__unused dev_t dev, struct uio *uio, int ioflag);
72 int cnwrite(__unused dev_t dev, struct uio *uio, int ioflag);
73 int cnioctl(__unused dev_t dev, u_long cmd, caddr_t addr, int flg, proc_t p);
74 int cnselect(__unused dev_t dev, int flag, void * wql, proc_t p);
75
76 static dev_t
cndev(void)77 cndev(void)
78 {
79 if (constty) {
80 return constty->t_dev;
81 } else {
82 return km_tty[0]->t_dev;
83 }
84 }
85
86 int
cnopen(__unused dev_t dev,int flag,int devtype,struct proc * pp)87 cnopen(__unused dev_t dev, int flag, int devtype, struct proc *pp)
88 {
89 dev = cndev();
90 return (*cdevsw[major(dev)].d_open)(dev, flag, devtype, pp);
91 }
92
93
94 int
cnclose(__unused dev_t dev,int flag,int mode,struct proc * pp)95 cnclose(__unused dev_t dev, int flag, int mode, struct proc *pp)
96 {
97 dev = cndev();
98 return (*cdevsw[major(dev)].d_close)(dev, flag, mode, pp);
99 }
100
101
102 int
cnread(__unused dev_t dev,struct uio * uio,int ioflag)103 cnread(__unused dev_t dev, struct uio *uio, int ioflag)
104 {
105 dev = cndev();
106 return (*cdevsw[major(dev)].d_read)(dev, uio, ioflag);
107 }
108
109
110 int
cnwrite(__unused dev_t dev,struct uio * uio,int ioflag)111 cnwrite(__unused dev_t dev, struct uio *uio, int ioflag)
112 {
113 dev = cndev();
114 return (*cdevsw[major(dev)].d_write)(dev, uio, ioflag);
115 }
116
117
118 int
cnioctl(__unused dev_t dev,u_long cmd,caddr_t addr,int flag,struct proc * p)119 cnioctl(__unused dev_t dev, u_long cmd, caddr_t addr, int flag, struct proc *p)
120 {
121 dev = cndev();
122 #if 0
123 /*
124 * Superuser can always use this to wrest control of console
125 * output from the "virtual" console.
126 *
127 * XXX Unfortunately, this code doesn't do what the author thougt
128 * XXX it did; use of the console device, a TIOCCONS would always
129 * XXX disassociate the console from a virtual terminal and send
130 * XXX it back to the fake tty.
131 */
132 if ((unsigned) cmd == TIOCCONS && constty) {
133 int error = proc_suser(p);
134 if (!error) {
135 constty = NULL;
136 }
137 return error;
138 }
139 #endif /* 0 */
140
141 return (*cdevsw[major(dev)].d_ioctl)(dev, cmd, addr, flag, p);
142 }
143
144
145 int
cnselect(__unused dev_t dev,int flag,void * wql,struct proc * p)146 cnselect(__unused dev_t dev, int flag, void *wql, struct proc *p)
147 {
148 dev = cndev();
149 return (*cdevsw[major(dev)].d_select)(dev, flag, wql, p);
150 }
151