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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * proc_tty.c -- handles /proc/tty
3 *
4 * Copyright 1997, Theodore Ts'o
5 */
6
7#include <asm/uaccess.h>
8
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
Linus Torvalds1da177e2005-04-16 15:20:36 -070018/*
19 * The /proc/tty directory inodes...
20 */
21static struct proc_dir_entry *proc_tty_ldisc, *proc_tty_driver;
22
23/*
24 * This is the handler for /proc/tty/drivers
25 */
26static void show_tty_range(struct seq_file *m, struct tty_driver *p,
27 dev_t from, int num)
28{
29 seq_printf(m, "%-20s ", p->driver_name ? p->driver_name : "unknown");
30 seq_printf(m, "/dev/%-8s ", p->name);
31 if (p->num > 1) {
32 seq_printf(m, "%3d %d-%d ", MAJOR(from), MINOR(from),
33 MINOR(from) + num - 1);
34 } else {
35 seq_printf(m, "%3d %7d ", MAJOR(from), MINOR(from));
36 }
37 switch (p->type) {
38 case TTY_DRIVER_TYPE_SYSTEM:
39 seq_printf(m, "system");
40 if (p->subtype == SYSTEM_TYPE_TTY)
41 seq_printf(m, ":/dev/tty");
42 else if (p->subtype == SYSTEM_TYPE_SYSCONS)
43 seq_printf(m, ":console");
44 else if (p->subtype == SYSTEM_TYPE_CONSOLE)
45 seq_printf(m, ":vtmaster");
46 break;
47 case TTY_DRIVER_TYPE_CONSOLE:
48 seq_printf(m, "console");
49 break;
50 case TTY_DRIVER_TYPE_SERIAL:
51 seq_printf(m, "serial");
52 break;
53 case TTY_DRIVER_TYPE_PTY:
54 if (p->subtype == PTY_TYPE_MASTER)
55 seq_printf(m, "pty:master");
56 else if (p->subtype == PTY_TYPE_SLAVE)
57 seq_printf(m, "pty:slave");
58 else
59 seq_printf(m, "pty");
60 break;
61 default:
62 seq_printf(m, "type:%d.%d", p->type, p->subtype);
63 }
64 seq_putc(m, '\n');
65}
66
67static int show_tty_driver(struct seq_file *m, void *v)
68{
Pavel Emelianov25216b02007-07-15 23:39:54 -070069 struct tty_driver *p = list_entry(v, struct tty_driver, tty_drivers);
Linus Torvalds1da177e2005-04-16 15:20:36 -070070 dev_t from = MKDEV(p->major, p->minor_start);
71 dev_t to = from + p->num;
72
73 if (&p->tty_drivers == tty_drivers.next) {
74 /* pseudo-drivers first */
75 seq_printf(m, "%-20s /dev/%-8s ", "/dev/tty", "tty");
76 seq_printf(m, "%3d %7d ", TTYAUX_MAJOR, 0);
77 seq_printf(m, "system:/dev/tty\n");
78 seq_printf(m, "%-20s /dev/%-8s ", "/dev/console", "console");
79 seq_printf(m, "%3d %7d ", TTYAUX_MAJOR, 1);
80 seq_printf(m, "system:console\n");
81#ifdef CONFIG_UNIX98_PTYS
82 seq_printf(m, "%-20s /dev/%-8s ", "/dev/ptmx", "ptmx");
83 seq_printf(m, "%3d %7d ", TTYAUX_MAJOR, 2);
84 seq_printf(m, "system\n");
85#endif
86#ifdef CONFIG_VT
87 seq_printf(m, "%-20s /dev/%-8s ", "/dev/vc/0", "vc/0");
88 seq_printf(m, "%3d %7d ", TTY_MAJOR, 0);
89 seq_printf(m, "system:vtmaster\n");
90#endif
91 }
92
93 while (MAJOR(from) < MAJOR(to)) {
94 dev_t next = MKDEV(MAJOR(from)+1, 0);
95 show_tty_range(m, p, from, next - from);
96 from = next;
97 }
98 if (from != to)
99 show_tty_range(m, p, from, to - from);
100 return 0;
101}
102
103/* iterator */
104static void *t_start(struct seq_file *m, loff_t *pos)
105{
Alexey Dobriyanca509f62007-05-08 00:27:12 -0700106 mutex_lock(&tty_mutex);
Pavel Emelianov25216b02007-07-15 23:39:54 -0700107 return seq_list_start(&tty_drivers, *pos);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700108}
109
110static void *t_next(struct seq_file *m, void *v, loff_t *pos)
111{
Pavel Emelianov25216b02007-07-15 23:39:54 -0700112 return seq_list_next(v, &tty_drivers, pos);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113}
114
115static void t_stop(struct seq_file *m, void *v)
116{
Alexey Dobriyanca509f62007-05-08 00:27:12 -0700117 mutex_unlock(&tty_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700118}
119
Jan Engelhardt03a44822008-02-08 04:21:19 -0800120static const struct seq_operations tty_drivers_op = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700121 .start = t_start,
122 .next = t_next,
123 .stop = t_stop,
124 .show = show_tty_driver
125};
126
127static int tty_drivers_open(struct inode *inode, struct file *file)
128{
129 return seq_open(file, &tty_drivers_op);
130}
131
Arjan van de Ven00977a52007-02-12 00:55:34 -0800132static const struct file_operations proc_tty_drivers_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133 .open = tty_drivers_open,
134 .read = seq_read,
135 .llseek = seq_lseek,
136 .release = seq_release,
137};
138
139/*
140 * This is the handler for /proc/tty/ldiscs
141 */
142static int tty_ldiscs_read_proc(char *page, char **start, off_t off,
143 int count, int *eof, void *data)
144{
145 int i;
146 int len = 0;
147 off_t begin = 0;
148 struct tty_ldisc *ld;
149
150 for (i=0; i < NR_LDISCS; i++) {
151 ld = tty_ldisc_get(i);
152 if (ld == NULL)
153 continue;
154 len += sprintf(page+len, "%-10s %2d\n",
155 ld->name ? ld->name : "???", i);
156 tty_ldisc_put(i);
157 if (len+begin > off+count)
158 break;
159 if (len+begin < off) {
160 begin += len;
161 len = 0;
162 }
163 }
164 if (i >= NR_LDISCS)
165 *eof = 1;
166 if (off >= len+begin)
167 return 0;
168 *start = page + (off-begin);
169 return ((count < begin+len-off) ? count : begin+len-off);
170}
171
172/*
173 * This function is called by tty_register_driver() to handle
174 * registering the driver's /proc handler into /proc/tty/driver/<foo>
175 */
176void proc_tty_register_driver(struct tty_driver *driver)
177{
178 struct proc_dir_entry *ent;
179
180 if ((!driver->read_proc && !driver->write_proc) ||
181 !driver->driver_name ||
182 driver->proc_entry)
183 return;
184
185 ent = create_proc_entry(driver->driver_name, 0, proc_tty_driver);
186 if (!ent)
187 return;
188 ent->read_proc = driver->read_proc;
189 ent->write_proc = driver->write_proc;
190 ent->owner = driver->owner;
191 ent->data = driver;
192
193 driver->proc_entry = ent;
194}
195
196/*
197 * This function is called by tty_unregister_driver()
198 */
199void proc_tty_unregister_driver(struct tty_driver *driver)
200{
201 struct proc_dir_entry *ent;
202
203 ent = driver->proc_entry;
204 if (!ent)
205 return;
206
207 remove_proc_entry(driver->driver_name, proc_tty_driver);
208
209 driver->proc_entry = NULL;
210}
211
212/*
213 * Called by proc_root_init() to initialize the /proc/tty subtree
214 */
215void __init proc_tty_init(void)
216{
217 struct proc_dir_entry *entry;
218 if (!proc_mkdir("tty", NULL))
219 return;
220 proc_tty_ldisc = proc_mkdir("tty/ldisc", NULL);
221 /*
222 * /proc/tty/driver/serial reveals the exact character counts for
223 * serial links which is just too easy to abuse for inferring
224 * password lengths and inter-keystroke timings during password
225 * entry.
226 */
227 proc_tty_driver = proc_mkdir_mode("tty/driver", S_IRUSR | S_IXUSR, NULL);
228
229 create_proc_read_entry("tty/ldiscs", 0, NULL, tty_ldiscs_read_proc, NULL);
230 entry = create_proc_entry("tty/drivers", 0, NULL);
231 if (entry)
232 entry->proc_fops = &proc_tty_drivers_operations;
233}