1 /* 2 * proc_tty.c -- handles /proc/tty 3 * 4 * Copyright 1997, Theodore Ts'o 5 */ 6 7 #include <linux/uaccess.h> 8 #include <linux/module.h> 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_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_puts(m, "system"); 40 if (p->subtype == SYSTEM_TYPE_TTY) 41 seq_puts(m, ":/dev/tty"); 42 else if (p->subtype == SYSTEM_TYPE_SYSCONS) 43 seq_puts(m, ":console"); 44 else if (p->subtype == SYSTEM_TYPE_CONSOLE) 45 seq_puts(m, ":vtmaster"); 46 break; 47 case TTY_DRIVER_TYPE_CONSOLE: 48 seq_puts(m, "console"); 49 break; 50 case TTY_DRIVER_TYPE_SERIAL: 51 seq_puts(m, "serial"); 52 break; 53 case TTY_DRIVER_TYPE_PTY: 54 if (p->subtype == PTY_TYPE_MASTER) 55 seq_puts(m, "pty:master"); 56 else if (p->subtype == PTY_TYPE_SLAVE) 57 seq_puts(m, "pty:slave"); 58 else 59 seq_puts(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_puts(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_puts(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_puts(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_puts(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 function is called by tty_register_driver() to handle 141 * registering the driver's /proc handler into /proc/tty/driver/<foo> 142 */ 143 void proc_tty_register_driver(struct tty_driver *driver) 144 { 145 struct proc_dir_entry *ent; 146 147 if (!driver->driver_name || driver->proc_entry || 148 !driver->ops->proc_fops) 149 return; 150 151 ent = proc_create_data(driver->driver_name, 0, proc_tty_driver, 152 driver->ops->proc_fops, driver); 153 driver->proc_entry = ent; 154 } 155 156 /* 157 * This function is called by tty_unregister_driver() 158 */ 159 void proc_tty_unregister_driver(struct tty_driver *driver) 160 { 161 struct proc_dir_entry *ent; 162 163 ent = driver->proc_entry; 164 if (!ent) 165 return; 166 167 remove_proc_entry(driver->driver_name, proc_tty_driver); 168 169 driver->proc_entry = NULL; 170 } 171 172 /* 173 * Called by proc_root_init() to initialize the /proc/tty subtree 174 */ 175 void __init proc_tty_init(void) 176 { 177 if (!proc_mkdir("tty", NULL)) 178 return; 179 proc_mkdir("tty/ldisc", NULL); /* Preserved: it's userspace visible */ 180 /* 181 * /proc/tty/driver/serial reveals the exact character counts for 182 * serial links which is just too easy to abuse for inferring 183 * password lengths and inter-keystroke timings during password 184 * entry. 185 */ 186 proc_tty_driver = proc_mkdir_mode("tty/driver", S_IRUSR|S_IXUSR, NULL); 187 proc_create("tty/ldiscs", 0, NULL, &tty_ldiscs_proc_fops); 188 proc_create("tty/drivers", 0, NULL, &proc_tty_drivers_operations); 189 } 190