1 /*
2 * Copyright (c) 2000-2007 Apple Inc. All rights reserved.
3 */
4 /*
5 * Copyright (c) 1987, 1988 NeXT, Inc.
6 *
7 * HISTORY 7-Jan-93 Mac Gillon (mgillon) at NeXT Integrated POSIX support
8 *
9 * 12-Aug-87 John Seamons (jks) at NeXT Ported to NeXT.
10 */
11
12 /*
13 * Indirect driver for console.
14 */
15 #include <kern/locks.h>
16 #include <machine/cons.h>
17 #include <sys/param.h>
18 #include <sys/systm.h>
19 #include <sys/conf.h>
20 #include <sys/ioctl.h>
21 #include <sys/tty.h>
22 #include <sys/proc.h>
23 #include <sys/uio.h>
24
25 static struct tty *_constty; /* current console device */
26 static LCK_GRP_DECLARE(_constty_lock_grp, "constty");
27 static LCK_MTX_DECLARE(_constty_lock, &_constty_lock_grp);
28
29 struct tty *
copy_constty(void)30 copy_constty(void)
31 {
32 struct tty *result = NULL;
33 lck_mtx_lock(&_constty_lock);
34 if (_constty != NULL) {
35 ttyhold(_constty);
36 result = _constty;
37 }
38 lck_mtx_unlock(&_constty_lock);
39 return result;
40 }
41
42 struct tty *
set_constty(struct tty * new_tty)43 set_constty(struct tty *new_tty)
44 {
45 struct tty *old_tty = NULL;
46 lck_mtx_lock(&_constty_lock);
47 old_tty = _constty;
48 _constty = new_tty;
49 if (_constty) {
50 ttyhold(_constty);
51 }
52 lck_mtx_unlock(&_constty_lock);
53
54 return old_tty;
55 }
56
57 /*
58 * The km driver supplied the default console device for the systems
59 * (usually a raw frame buffer driver, but potentially a serial driver).
60 */
61 extern struct tty *km_tty[1];
62
63 /*
64 * cdevsw[] entries for the console device driver
65 */
66 int cnopen(__unused dev_t dev, int flag, int devtype, proc_t pp);
67 int cnclose(__unused dev_t dev, int flag, int mode, proc_t pp);
68 int cnread(__unused dev_t dev, struct uio *uio, int ioflag);
69 int cnwrite(__unused dev_t dev, struct uio *uio, int ioflag);
70 int cnioctl(__unused dev_t dev, u_long cmd, caddr_t addr, int flg, proc_t p);
71 int cnselect(__unused dev_t dev, int flag, void * wql, proc_t p);
72
73 int
cnopen(__unused dev_t dev,int flag,int devtype,struct proc * pp)74 cnopen(__unused dev_t dev, int flag, int devtype, struct proc *pp)
75 {
76 int error;
77 struct tty *constty = copy_constty();
78 if (constty) {
79 dev = constty->t_dev;
80 } else {
81 dev = km_tty[0]->t_dev;
82 }
83 error = (*cdevsw[major(dev)].d_open)(dev, flag, devtype, pp);
84 if (constty != NULL) {
85 ttyfree(constty);
86 }
87 return error;
88 }
89
90
91 int
cnclose(__unused dev_t dev,int flag,int mode,struct proc * pp)92 cnclose(__unused dev_t dev, int flag, int mode, struct proc *pp)
93 {
94 int error;
95 struct tty *constty = copy_constty();
96 if (constty) {
97 dev = constty->t_dev;
98 } else {
99 dev = km_tty[0]->t_dev;
100 }
101 error = (*cdevsw[major(dev)].d_close)(dev, flag, mode, pp);
102 if (constty != NULL) {
103 ttyfree(constty);
104 }
105 return error;
106 }
107
108
109 int
cnread(__unused dev_t dev,struct uio * uio,int ioflag)110 cnread(__unused dev_t dev, struct uio *uio, int ioflag)
111 {
112 int error;
113 struct tty *constty = copy_constty();
114 if (constty) {
115 dev = constty->t_dev;
116 } else {
117 dev = km_tty[0]->t_dev;
118 }
119 error = (*cdevsw[major(dev)].d_read)(dev, uio, ioflag);
120 if (constty != NULL) {
121 ttyfree(constty);
122 }
123 return error;
124 }
125
126
127 int
cnwrite(__unused dev_t dev,struct uio * uio,int ioflag)128 cnwrite(__unused dev_t dev, struct uio *uio, int ioflag)
129 {
130 int error;
131 struct tty *constty = copy_constty();
132 if (constty) {
133 dev = constty->t_dev;
134 } else {
135 dev = km_tty[0]->t_dev;
136 }
137 error = (*cdevsw[major(dev)].d_write)(dev, uio, ioflag);
138 if (constty != NULL) {
139 ttyfree(constty);
140 }
141 return error;
142 }
143
144
145 int
cnioctl(__unused dev_t dev,u_long cmd,caddr_t addr,int flag,struct proc * p)146 cnioctl(__unused dev_t dev, u_long cmd, caddr_t addr, int flag, struct proc *p)
147 {
148 int error;
149 struct tty *constty = copy_constty();
150 struct tty *freetp = NULL;
151 if (constty) {
152 dev = constty->t_dev;
153 } else {
154 dev = km_tty[0]->t_dev;
155 }
156
157 /*
158 * XXX This check prevents the cons.c code from being shared between
159 * XXX all architectures; it is probably not needed on ARM, either,
160 * XXX but I have no test platforms or ability to run a kernel.
161 *
162 * Superuser can always use this to wrest control of console
163 * output from the "virtual" console.
164 */
165 if ((unsigned) cmd == TIOCCONS && constty) {
166 error = proc_suser(p);
167 if (error) {
168 goto finish;
169 }
170 freetp = set_constty(NULL);
171 if (freetp) {
172 ttyfree(freetp);
173 freetp = NULL;
174 }
175 } else {
176 error = (*cdevsw[major(dev)].d_ioctl)(dev, cmd, addr, flag, p);
177 }
178 finish:
179 if (constty != NULL) {
180 ttyfree(constty);
181 }
182 return error;
183 }
184
185
186 int
cnselect(__unused dev_t dev,int flag,void * wql,struct proc * p)187 cnselect(__unused dev_t dev, int flag, void *wql, struct proc *p)
188 {
189 int error;
190 struct tty *constty = copy_constty();
191 if (constty) {
192 dev = constty->t_dev;
193 } else {
194 dev = km_tty[0]->t_dev;
195 }
196 error = (*cdevsw[major(dev)].d_select)(dev, flag, wql, p);
197 if (constty != NULL) {
198 ttyfree(constty);
199 }
200 return error;
201 }
202