1 /*
2 * proc_tty.c -- handles /proc/tty
3 *
4 * Copyright 1997, Theodore Ts'o
5 */
6
7 #include <asm/uaccess.h>
8 #include <linux/module.h>
9 #include <linux/init.h>
10 #include <linux/errno.h>
11 #include <linux/time.h>
12 #include <linux/proc_fs.h>
13 #include <linux/stat.h>
14 #include <linux/tty.h>
15 #include <linux/seq_file.h>
16 #include <linux/bitops.h>
17 #include "internal.h"
18
19 /*
20 * The /proc/tty directory inodes...
21 */
22 static struct proc_dir_entry *proc_tty_driver;
23
24 /*
25 * This is the handler for /proc/tty/drivers
26 */
show_tty_range(struct seq_file * m,struct tty_driver * p,dev_t from,int num)27 static void show_tty_range(struct seq_file *m, struct tty_driver *p,
28 dev_t from, int num)
29 {
30 seq_printf(m, "%-20s ", p->driver_name ? p->driver_name : "unknown");
31 seq_printf(m, "/dev/%-8s ", p->name);
32 if (p->num > 1) {
33 seq_printf(m, "%3d %d-%d ", MAJOR(from), MINOR(from),
34 MINOR(from) + num - 1);
35 } else {
36 seq_printf(m, "%3d %7d ", MAJOR(from), MINOR(from));
37 }
38 switch (p->type) {
39 case TTY_DRIVER_TYPE_SYSTEM:
40 seq_puts(m, "system");
41 if (p->subtype == SYSTEM_TYPE_TTY)
42 seq_puts(m, ":/dev/tty");
43 else if (p->subtype == SYSTEM_TYPE_SYSCONS)
44 seq_puts(m, ":console");
45 else if (p->subtype == SYSTEM_TYPE_CONSOLE)
46 seq_puts(m, ":vtmaster");
47 break;
48 case TTY_DRIVER_TYPE_CONSOLE:
49 seq_puts(m, "console");
50 break;
51 case TTY_DRIVER_TYPE_SERIAL:
52 seq_puts(m, "serial");
53 break;
54 case TTY_DRIVER_TYPE_PTY:
55 if (p->subtype == PTY_TYPE_MASTER)
56 seq_puts(m, "pty:master");
57 else if (p->subtype == PTY_TYPE_SLAVE)
58 seq_puts(m, "pty:slave");
59 else
60 seq_puts(m, "pty");
61 break;
62 default:
63 seq_printf(m, "type:%d.%d", p->type, p->subtype);
64 }
65 seq_putc(m, '\n');
66 }
67
show_tty_driver(struct seq_file * m,void * v)68 static int show_tty_driver(struct seq_file *m, void *v)
69 {
70 struct tty_driver *p = list_entry(v, struct tty_driver, tty_drivers);
71 dev_t from = MKDEV(p->major, p->minor_start);
72 dev_t to = from + p->num;
73
74 if (&p->tty_drivers == tty_drivers.next) {
75 /* pseudo-drivers first */
76 seq_printf(m, "%-20s /dev/%-8s ", "/dev/tty", "tty");
77 seq_printf(m, "%3d %7d ", TTYAUX_MAJOR, 0);
78 seq_puts(m, "system:/dev/tty\n");
79 seq_printf(m, "%-20s /dev/%-8s ", "/dev/console", "console");
80 seq_printf(m, "%3d %7d ", TTYAUX_MAJOR, 1);
81 seq_puts(m, "system:console\n");
82 #ifdef CONFIG_UNIX98_PTYS
83 seq_printf(m, "%-20s /dev/%-8s ", "/dev/ptmx", "ptmx");
84 seq_printf(m, "%3d %7d ", TTYAUX_MAJOR, 2);
85 seq_puts(m, "system\n");
86 #endif
87 #ifdef CONFIG_VT
88 seq_printf(m, "%-20s /dev/%-8s ", "/dev/vc/0", "vc/0");
89 seq_printf(m, "%3d %7d ", TTY_MAJOR, 0);
90 seq_puts(m, "system:vtmaster\n");
91 #endif
92 }
93
94 while (MAJOR(from) < MAJOR(to)) {
95 dev_t next = MKDEV(MAJOR(from)+1, 0);
96 show_tty_range(m, p, from, next - from);
97 from = next;
98 }
99 if (from != to)
100 show_tty_range(m, p, from, to - from);
101 return 0;
102 }
103
104 /* iterator */
t_start(struct seq_file * m,loff_t * pos)105 static void *t_start(struct seq_file *m, loff_t *pos)
106 {
107 mutex_lock(&tty_mutex);
108 return seq_list_start(&tty_drivers, *pos);
109 }
110
t_next(struct seq_file * m,void * v,loff_t * pos)111 static void *t_next(struct seq_file *m, void *v, loff_t *pos)
112 {
113 return seq_list_next(v, &tty_drivers, pos);
114 }
115
t_stop(struct seq_file * m,void * v)116 static void t_stop(struct seq_file *m, void *v)
117 {
118 mutex_unlock(&tty_mutex);
119 }
120
121 static const struct seq_operations tty_drivers_op = {
122 .start = t_start,
123 .next = t_next,
124 .stop = t_stop,
125 .show = show_tty_driver
126 };
127
tty_drivers_open(struct inode * inode,struct file * file)128 static int tty_drivers_open(struct inode *inode, struct file *file)
129 {
130 return seq_open(file, &tty_drivers_op);
131 }
132
133 static const struct file_operations proc_tty_drivers_operations = {
134 .open = tty_drivers_open,
135 .read = seq_read,
136 .llseek = seq_lseek,
137 .release = seq_release,
138 };
139
140 /*
141 * This function is called by tty_register_driver() to handle
142 * registering the driver's /proc handler into /proc/tty/driver/<foo>
143 */
proc_tty_register_driver(struct tty_driver * driver)144 void proc_tty_register_driver(struct tty_driver *driver)
145 {
146 struct proc_dir_entry *ent;
147
148 if (!driver->driver_name || driver->proc_entry ||
149 !driver->ops->proc_fops)
150 return;
151
152 ent = proc_create_data(driver->driver_name, 0, proc_tty_driver,
153 driver->ops->proc_fops, driver);
154 driver->proc_entry = ent;
155 }
156
157 /*
158 * This function is called by tty_unregister_driver()
159 */
proc_tty_unregister_driver(struct tty_driver * driver)160 void proc_tty_unregister_driver(struct tty_driver *driver)
161 {
162 struct proc_dir_entry *ent;
163
164 ent = driver->proc_entry;
165 if (!ent)
166 return;
167
168 remove_proc_entry(ent->name, proc_tty_driver);
169
170 driver->proc_entry = NULL;
171 }
172
173 /*
174 * Called by proc_root_init() to initialize the /proc/tty subtree
175 */
proc_tty_init(void)176 void __init proc_tty_init(void)
177 {
178 if (!proc_mkdir("tty", NULL))
179 return;
180 proc_mkdir("tty/ldisc", NULL); /* Preserved: it's userspace visible */
181 /*
182 * /proc/tty/driver/serial reveals the exact character counts for
183 * serial links which is just too easy to abuse for inferring
184 * password lengths and inter-keystroke timings during password
185 * entry.
186 */
187 proc_tty_driver = proc_mkdir_mode("tty/driver", S_IRUSR|S_IXUSR, NULL);
188 proc_create("tty/ldiscs", 0, NULL, &tty_ldiscs_proc_fops);
189 proc_create("tty/drivers", 0, NULL, &proc_tty_drivers_operations);
190 }
191