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