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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
18static int tty_ldiscs_read_proc(char *page, char **start, off_t off,
19 int count, int *eof, void *data);
20
21/*
22 * The /proc/tty directory inodes...
23 */
24static struct proc_dir_entry *proc_tty_ldisc, *proc_tty_driver;
25
26/*
27 * This is the handler for /proc/tty/drivers
28 */
29static void show_tty_range(struct seq_file *m, struct tty_driver *p,
30 dev_t from, int num)
31{
32 seq_printf(m, "%-20s ", p->driver_name ? p->driver_name : "unknown");
33 seq_printf(m, "/dev/%-8s ", p->name);
34 if (p->num > 1) {
35 seq_printf(m, "%3d %d-%d ", MAJOR(from), MINOR(from),
36 MINOR(from) + num - 1);
37 } else {
38 seq_printf(m, "%3d %7d ", MAJOR(from), MINOR(from));
39 }
40 switch (p->type) {
41 case TTY_DRIVER_TYPE_SYSTEM:
42 seq_printf(m, "system");
43 if (p->subtype == SYSTEM_TYPE_TTY)
44 seq_printf(m, ":/dev/tty");
45 else if (p->subtype == SYSTEM_TYPE_SYSCONS)
46 seq_printf(m, ":console");
47 else if (p->subtype == SYSTEM_TYPE_CONSOLE)
48 seq_printf(m, ":vtmaster");
49 break;
50 case TTY_DRIVER_TYPE_CONSOLE:
51 seq_printf(m, "console");
52 break;
53 case TTY_DRIVER_TYPE_SERIAL:
54 seq_printf(m, "serial");
55 break;
56 case TTY_DRIVER_TYPE_PTY:
57 if (p->subtype == PTY_TYPE_MASTER)
58 seq_printf(m, "pty:master");
59 else if (p->subtype == PTY_TYPE_SLAVE)
60 seq_printf(m, "pty:slave");
61 else
62 seq_printf(m, "pty");
63 break;
64 default:
65 seq_printf(m, "type:%d.%d", p->type, p->subtype);
66 }
67 seq_putc(m, '\n');
68}
69
70static int show_tty_driver(struct seq_file *m, void *v)
71{
72 struct tty_driver *p = v;
73 dev_t from = MKDEV(p->major, p->minor_start);
74 dev_t to = from + p->num;
75
76 if (&p->tty_drivers == tty_drivers.next) {
77 /* pseudo-drivers first */
78 seq_printf(m, "%-20s /dev/%-8s ", "/dev/tty", "tty");
79 seq_printf(m, "%3d %7d ", TTYAUX_MAJOR, 0);
80 seq_printf(m, "system:/dev/tty\n");
81 seq_printf(m, "%-20s /dev/%-8s ", "/dev/console", "console");
82 seq_printf(m, "%3d %7d ", TTYAUX_MAJOR, 1);
83 seq_printf(m, "system:console\n");
84#ifdef CONFIG_UNIX98_PTYS
85 seq_printf(m, "%-20s /dev/%-8s ", "/dev/ptmx", "ptmx");
86 seq_printf(m, "%3d %7d ", TTYAUX_MAJOR, 2);
87 seq_printf(m, "system\n");
88#endif
89#ifdef CONFIG_VT
90 seq_printf(m, "%-20s /dev/%-8s ", "/dev/vc/0", "vc/0");
91 seq_printf(m, "%3d %7d ", TTY_MAJOR, 0);
92 seq_printf(m, "system:vtmaster\n");
93#endif
94 }
95
96 while (MAJOR(from) < MAJOR(to)) {
97 dev_t next = MKDEV(MAJOR(from)+1, 0);
98 show_tty_range(m, p, from, next - from);
99 from = next;
100 }
101 if (from != to)
102 show_tty_range(m, p, from, to - from);
103 return 0;
104}
105
106/* iterator */
107static void *t_start(struct seq_file *m, loff_t *pos)
108{
109 struct list_head *p;
110 loff_t l = *pos;
Alexey Dobriyanca509f62007-05-08 00:27:12 -0700111
112 mutex_lock(&tty_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113 list_for_each(p, &tty_drivers)
114 if (!l--)
115 return list_entry(p, struct tty_driver, tty_drivers);
116 return NULL;
117}
118
119static void *t_next(struct seq_file *m, void *v, loff_t *pos)
120{
121 struct list_head *p = ((struct tty_driver *)v)->tty_drivers.next;
122 (*pos)++;
123 return p==&tty_drivers ? NULL :
124 list_entry(p, struct tty_driver, tty_drivers);
125}
126
127static void t_stop(struct seq_file *m, void *v)
128{
Alexey Dobriyanca509f62007-05-08 00:27:12 -0700129 mutex_unlock(&tty_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130}
131
132static struct seq_operations tty_drivers_op = {
133 .start = t_start,
134 .next = t_next,
135 .stop = t_stop,
136 .show = show_tty_driver
137};
138
139static int tty_drivers_open(struct inode *inode, struct file *file)
140{
141 return seq_open(file, &tty_drivers_op);
142}
143
Arjan van de Ven00977a52007-02-12 00:55:34 -0800144static const struct file_operations proc_tty_drivers_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700145 .open = tty_drivers_open,
146 .read = seq_read,
147 .llseek = seq_lseek,
148 .release = seq_release,
149};
150
151/*
152 * This is the handler for /proc/tty/ldiscs
153 */
154static int tty_ldiscs_read_proc(char *page, char **start, off_t off,
155 int count, int *eof, void *data)
156{
157 int i;
158 int len = 0;
159 off_t begin = 0;
160 struct tty_ldisc *ld;
161
162 for (i=0; i < NR_LDISCS; i++) {
163 ld = tty_ldisc_get(i);
164 if (ld == NULL)
165 continue;
166 len += sprintf(page+len, "%-10s %2d\n",
167 ld->name ? ld->name : "???", i);
168 tty_ldisc_put(i);
169 if (len+begin > off+count)
170 break;
171 if (len+begin < off) {
172 begin += len;
173 len = 0;
174 }
175 }
176 if (i >= NR_LDISCS)
177 *eof = 1;
178 if (off >= len+begin)
179 return 0;
180 *start = page + (off-begin);
181 return ((count < begin+len-off) ? count : begin+len-off);
182}
183
184/*
185 * This function is called by tty_register_driver() to handle
186 * registering the driver's /proc handler into /proc/tty/driver/<foo>
187 */
188void proc_tty_register_driver(struct tty_driver *driver)
189{
190 struct proc_dir_entry *ent;
191
192 if ((!driver->read_proc && !driver->write_proc) ||
193 !driver->driver_name ||
194 driver->proc_entry)
195 return;
196
197 ent = create_proc_entry(driver->driver_name, 0, proc_tty_driver);
198 if (!ent)
199 return;
200 ent->read_proc = driver->read_proc;
201 ent->write_proc = driver->write_proc;
202 ent->owner = driver->owner;
203 ent->data = driver;
204
205 driver->proc_entry = ent;
206}
207
208/*
209 * This function is called by tty_unregister_driver()
210 */
211void proc_tty_unregister_driver(struct tty_driver *driver)
212{
213 struct proc_dir_entry *ent;
214
215 ent = driver->proc_entry;
216 if (!ent)
217 return;
218
219 remove_proc_entry(driver->driver_name, proc_tty_driver);
220
221 driver->proc_entry = NULL;
222}
223
224/*
225 * Called by proc_root_init() to initialize the /proc/tty subtree
226 */
227void __init proc_tty_init(void)
228{
229 struct proc_dir_entry *entry;
230 if (!proc_mkdir("tty", NULL))
231 return;
232 proc_tty_ldisc = proc_mkdir("tty/ldisc", NULL);
233 /*
234 * /proc/tty/driver/serial reveals the exact character counts for
235 * serial links which is just too easy to abuse for inferring
236 * password lengths and inter-keystroke timings during password
237 * entry.
238 */
239 proc_tty_driver = proc_mkdir_mode("tty/driver", S_IRUSR | S_IXUSR, NULL);
240
241 create_proc_read_entry("tty/ldiscs", 0, NULL, tty_ldiscs_read_proc, NULL);
242 entry = create_proc_entry("tty/drivers", 0, NULL);
243 if (entry)
244 entry->proc_fops = &proc_tty_drivers_operations;
245}