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; 111 112 mutex_lock(&tty_mutex); 113 list_for_each(p, &tty_drivers) 114 if (!l--) 115 return list_entry(p, struct tty_driver, tty_drivers); 116 return NULL; 117 } 118 119 static 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 } 126 127 static void t_stop(struct seq_file *m, void *v) 128 { 129 mutex_unlock(&tty_mutex); 130 } 131 132 static struct seq_operations tty_drivers_op = { 133 .start = t_start, 134 .next = t_next, 135 .stop = t_stop, 136 .show = show_tty_driver 137 }; 138 139 static int tty_drivers_open(struct inode *inode, struct file *file) 140 { 141 return seq_open(file, &tty_drivers_op); 142 } 143 144 static const struct file_operations proc_tty_drivers_operations = { 145 .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 */ 154 static 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 */ 188 void 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 */ 211 void 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 */ 227 void __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 } 246