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 /* 19 * The /proc/tty directory inodes... 20 */ 21 static struct proc_dir_entry *proc_tty_ldisc, *proc_tty_driver; 22 23 /* 24 * This is the handler for /proc/tty/drivers 25 */ 26 static 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 67 static int show_tty_driver(struct seq_file *m, void *v) 68 { 69 struct tty_driver *p = list_entry(v, struct tty_driver, tty_drivers); 70 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 */ 104 static void *t_start(struct seq_file *m, loff_t *pos) 105 { 106 mutex_lock(&tty_mutex); 107 return seq_list_start(&tty_drivers, *pos); 108 } 109 110 static void *t_next(struct seq_file *m, void *v, loff_t *pos) 111 { 112 return seq_list_next(v, &tty_drivers, pos); 113 } 114 115 static void t_stop(struct seq_file *m, void *v) 116 { 117 mutex_unlock(&tty_mutex); 118 } 119 120 static const struct seq_operations tty_drivers_op = { 121 .start = t_start, 122 .next = t_next, 123 .stop = t_stop, 124 .show = show_tty_driver 125 }; 126 127 static int tty_drivers_open(struct inode *inode, struct file *file) 128 { 129 return seq_open(file, &tty_drivers_op); 130 } 131 132 static const struct file_operations proc_tty_drivers_operations = { 133 .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 */ 142 static 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 */ 176 void 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 */ 199 void 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 */ 215 void __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 } 234