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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 | |
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 | |
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 | |
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 | |
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 | |
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 | |
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 | |
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 | } |