[PATCH] mark struct file_operations const 6
[linux-2.6.git] / fs / proc / proc_tty.c
1 /*
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
18 static 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  */
24 static struct proc_dir_entry *proc_tty_ldisc, *proc_tty_driver;
25
26 /*
27  * This is the handler for /proc/tty/drivers
28  */
29 static 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
70 static 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 */
107 static void *t_start(struct seq_file *m, loff_t *pos)
108 {
109         struct list_head *p;
110         loff_t l = *pos;
111         list_for_each(p, &tty_drivers)
112                 if (!l--)
113                         return list_entry(p, struct tty_driver, tty_drivers);
114         return NULL;
115 }
116
117 static void *t_next(struct seq_file *m, void *v, loff_t *pos)
118 {
119         struct list_head *p = ((struct tty_driver *)v)->tty_drivers.next;
120         (*pos)++;
121         return p==&tty_drivers ? NULL :
122                         list_entry(p, struct tty_driver, tty_drivers);
123 }
124
125 static void t_stop(struct seq_file *m, void *v)
126 {
127 }
128
129 static struct seq_operations tty_drivers_op = {
130         .start  = t_start,
131         .next   = t_next,
132         .stop   = t_stop,
133         .show   = show_tty_driver
134 };
135
136 static int tty_drivers_open(struct inode *inode, struct file *file)
137 {
138         return seq_open(file, &tty_drivers_op);
139 }
140
141 static const struct file_operations proc_tty_drivers_operations = {
142         .open           = tty_drivers_open,
143         .read           = seq_read,
144         .llseek         = seq_lseek,
145         .release        = seq_release,
146 };
147
148 /*
149  * This is the handler for /proc/tty/ldiscs
150  */
151 static int tty_ldiscs_read_proc(char *page, char **start, off_t off,
152                                 int count, int *eof, void *data)
153 {
154         int     i;
155         int     len = 0;
156         off_t   begin = 0;
157         struct tty_ldisc *ld;
158         
159         for (i=0; i < NR_LDISCS; i++) {
160                 ld = tty_ldisc_get(i);
161                 if (ld == NULL)
162                         continue;
163                 len += sprintf(page+len, "%-10s %2d\n",
164                                ld->name ? ld->name : "???", i);
165                 tty_ldisc_put(i);
166                 if (len+begin > off+count)
167                         break;
168                 if (len+begin < off) {
169                         begin += len;
170                         len = 0;
171                 }
172         }
173         if (i >= NR_LDISCS)
174                 *eof = 1;
175         if (off >= len+begin)
176                 return 0;
177         *start = page + (off-begin);
178         return ((count < begin+len-off) ? count : begin+len-off);
179 }
180
181 /*
182  * This function is called by tty_register_driver() to handle
183  * registering the driver's /proc handler into /proc/tty/driver/<foo>
184  */
185 void proc_tty_register_driver(struct tty_driver *driver)
186 {
187         struct proc_dir_entry *ent;
188                 
189         if ((!driver->read_proc && !driver->write_proc) ||
190             !driver->driver_name ||
191             driver->proc_entry)
192                 return;
193
194         ent = create_proc_entry(driver->driver_name, 0, proc_tty_driver);
195         if (!ent)
196                 return;
197         ent->read_proc = driver->read_proc;
198         ent->write_proc = driver->write_proc;
199         ent->owner = driver->owner;
200         ent->data = driver;
201
202         driver->proc_entry = ent;
203 }
204
205 /*
206  * This function is called by tty_unregister_driver()
207  */
208 void proc_tty_unregister_driver(struct tty_driver *driver)
209 {
210         struct proc_dir_entry *ent;
211
212         ent = driver->proc_entry;
213         if (!ent)
214                 return;
215                 
216         remove_proc_entry(driver->driver_name, proc_tty_driver);
217         
218         driver->proc_entry = NULL;
219 }
220
221 /*
222  * Called by proc_root_init() to initialize the /proc/tty subtree
223  */
224 void __init proc_tty_init(void)
225 {
226         struct proc_dir_entry *entry;
227         if (!proc_mkdir("tty", NULL))
228                 return;
229         proc_tty_ldisc = proc_mkdir("tty/ldisc", NULL);
230         /*
231          * /proc/tty/driver/serial reveals the exact character counts for
232          * serial links which is just too easy to abuse for inferring
233          * password lengths and inter-keystroke timings during password
234          * entry.
235          */
236         proc_tty_driver = proc_mkdir_mode("tty/driver", S_IRUSR | S_IXUSR, NULL);
237
238         create_proc_read_entry("tty/ldiscs", 0, NULL, tty_ldiscs_read_proc, NULL);
239         entry = create_proc_entry("tty/drivers", 0, NULL);
240         if (entry)
241                 entry->proc_fops = &proc_tty_drivers_operations;
242 }