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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
1da177e4 LT |
2 | /* |
3 | * proc_tty.c -- handles /proc/tty | |
4 | * | |
5 | * Copyright 1997, Theodore Ts'o | |
6 | */ | |
7 | ||
7c0f6ba6 | 8 | #include <linux/uaccess.h> |
b640a89d | 9 | #include <linux/module.h> |
1da177e4 LT |
10 | #include <linux/init.h> |
11 | #include <linux/errno.h> | |
12 | #include <linux/time.h> | |
13 | #include <linux/proc_fs.h> | |
14 | #include <linux/stat.h> | |
15 | #include <linux/tty.h> | |
16 | #include <linux/seq_file.h> | |
17 | #include <linux/bitops.h> | |
18 | ||
1da177e4 LT |
19 | /* |
20 | * The /proc/tty directory inodes... | |
21 | */ | |
849d20a1 | 22 | static struct proc_dir_entry *proc_tty_driver; |
1da177e4 LT |
23 | |
24 | /* | |
25 | * This is the handler for /proc/tty/drivers | |
26 | */ | |
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: | |
9d6de12f | 40 | seq_puts(m, "system"); |
1da177e4 | 41 | if (p->subtype == SYSTEM_TYPE_TTY) |
9d6de12f | 42 | seq_puts(m, ":/dev/tty"); |
1da177e4 | 43 | else if (p->subtype == SYSTEM_TYPE_SYSCONS) |
9d6de12f | 44 | seq_puts(m, ":console"); |
1da177e4 | 45 | else if (p->subtype == SYSTEM_TYPE_CONSOLE) |
9d6de12f | 46 | seq_puts(m, ":vtmaster"); |
1da177e4 LT |
47 | break; |
48 | case TTY_DRIVER_TYPE_CONSOLE: | |
9d6de12f | 49 | seq_puts(m, "console"); |
1da177e4 LT |
50 | break; |
51 | case TTY_DRIVER_TYPE_SERIAL: | |
9d6de12f | 52 | seq_puts(m, "serial"); |
1da177e4 LT |
53 | break; |
54 | case TTY_DRIVER_TYPE_PTY: | |
55 | if (p->subtype == PTY_TYPE_MASTER) | |
9d6de12f | 56 | seq_puts(m, "pty:master"); |
1da177e4 | 57 | else if (p->subtype == PTY_TYPE_SLAVE) |
9d6de12f | 58 | seq_puts(m, "pty:slave"); |
1da177e4 | 59 | else |
9d6de12f | 60 | seq_puts(m, "pty"); |
1da177e4 LT |
61 | break; |
62 | default: | |
63 | seq_printf(m, "type:%d.%d", p->type, p->subtype); | |
64 | } | |
65 | seq_putc(m, '\n'); | |
66 | } | |
67 | ||
68 | static int show_tty_driver(struct seq_file *m, void *v) | |
69 | { | |
25216b00 | 70 | struct tty_driver *p = list_entry(v, struct tty_driver, tty_drivers); |
1da177e4 LT |
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); | |
9d6de12f | 78 | seq_puts(m, "system:/dev/tty\n"); |
1da177e4 LT |
79 | seq_printf(m, "%-20s /dev/%-8s ", "/dev/console", "console"); |
80 | seq_printf(m, "%3d %7d ", TTYAUX_MAJOR, 1); | |
9d6de12f | 81 | seq_puts(m, "system:console\n"); |
1da177e4 LT |
82 | #ifdef CONFIG_UNIX98_PTYS |
83 | seq_printf(m, "%-20s /dev/%-8s ", "/dev/ptmx", "ptmx"); | |
84 | seq_printf(m, "%3d %7d ", TTYAUX_MAJOR, 2); | |
9d6de12f | 85 | seq_puts(m, "system\n"); |
1da177e4 LT |
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); | |
9d6de12f | 90 | seq_puts(m, "system:vtmaster\n"); |
1da177e4 LT |
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 */ | |
105 | static void *t_start(struct seq_file *m, loff_t *pos) | |
106 | { | |
ca509f69 | 107 | mutex_lock(&tty_mutex); |
25216b00 | 108 | return seq_list_start(&tty_drivers, *pos); |
1da177e4 LT |
109 | } |
110 | ||
111 | static void *t_next(struct seq_file *m, void *v, loff_t *pos) | |
112 | { | |
25216b00 | 113 | return seq_list_next(v, &tty_drivers, pos); |
1da177e4 LT |
114 | } |
115 | ||
116 | static void t_stop(struct seq_file *m, void *v) | |
117 | { | |
ca509f69 | 118 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
119 | } |
120 | ||
03a44825 | 121 | static const struct seq_operations tty_drivers_op = { |
1da177e4 LT |
122 | .start = t_start, |
123 | .next = t_next, | |
124 | .stop = t_stop, | |
125 | .show = show_tty_driver | |
126 | }; | |
127 | ||
128 | static int tty_drivers_open(struct inode *inode, struct file *file) | |
129 | { | |
130 | return seq_open(file, &tty_drivers_op); | |
131 | } | |
132 | ||
00977a59 | 133 | static const struct file_operations proc_tty_drivers_operations = { |
1da177e4 LT |
134 | .open = tty_drivers_open, |
135 | .read = seq_read, | |
136 | .llseek = seq_lseek, | |
137 | .release = seq_release, | |
138 | }; | |
139 | ||
1da177e4 LT |
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 | */ | |
144 | void proc_tty_register_driver(struct tty_driver *driver) | |
145 | { | |
146 | struct proc_dir_entry *ent; | |
147 | ||
0f043a81 AD |
148 | if (!driver->driver_name || driver->proc_entry || |
149 | !driver->ops->proc_fops) | |
1da177e4 LT |
150 | return; |
151 | ||
0f043a81 AD |
152 | ent = proc_create_data(driver->driver_name, 0, proc_tty_driver, |
153 | driver->ops->proc_fops, driver); | |
1da177e4 LT |
154 | driver->proc_entry = ent; |
155 | } | |
156 | ||
157 | /* | |
158 | * This function is called by tty_unregister_driver() | |
159 | */ | |
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(driver->driver_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 | */ | |
176 | void __init proc_tty_init(void) | |
177 | { | |
1da177e4 LT |
178 | if (!proc_mkdir("tty", NULL)) |
179 | return; | |
849d20a1 | 180 | proc_mkdir("tty/ldisc", NULL); /* Preserved: it's userspace visible */ |
1da177e4 LT |
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 | */ | |
b640a89d AD |
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); | |
0d5c9f5f | 189 | proc_create("tty/drivers", 0, NULL, &proc_tty_drivers_operations); |
1da177e4 | 190 | } |