1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_TTY_H
3 #define _LINUX_TTY_H
4
5 #include <linux/fs.h>
6 #include <linux/major.h>
7 #include <linux/termios.h>
8 #include <linux/workqueue.h>
9 #include <linux/tty_driver.h>
10 #include <linux/tty_ldisc.h>
11 #include <linux/tty_port.h>
12 #include <linux/mutex.h>
13 #include <linux/tty_flags.h>
14 #include <uapi/linux/tty.h>
15 #include <linux/rwsem.h>
16 #include <linux/llist.h>
17 #include <linux/android_kabi.h>
18
19
20 /*
21 * (Note: the *_driver.minor_start values 1, 64, 128, 192 are
22 * hardcoded at present.)
23 */
24 #define NR_UNIX98_PTY_DEFAULT 4096 /* Default maximum for Unix98 ptys */
25 #define NR_UNIX98_PTY_RESERVE 1024 /* Default reserve for main devpts */
26 #define NR_UNIX98_PTY_MAX (1 << MINORBITS) /* Absolute limit */
27
28 /*
29 * This character is the same as _POSIX_VDISABLE: it cannot be used as
30 * a c_cc[] character, but indicates that a particular special character
31 * isn't in use (eg VINTR has no character etc)
32 */
33 #define __DISABLED_CHAR '\0'
34
35 #define INTR_CHAR(tty) ((tty)->termios.c_cc[VINTR])
36 #define QUIT_CHAR(tty) ((tty)->termios.c_cc[VQUIT])
37 #define ERASE_CHAR(tty) ((tty)->termios.c_cc[VERASE])
38 #define KILL_CHAR(tty) ((tty)->termios.c_cc[VKILL])
39 #define EOF_CHAR(tty) ((tty)->termios.c_cc[VEOF])
40 #define TIME_CHAR(tty) ((tty)->termios.c_cc[VTIME])
41 #define MIN_CHAR(tty) ((tty)->termios.c_cc[VMIN])
42 #define SWTC_CHAR(tty) ((tty)->termios.c_cc[VSWTC])
43 #define START_CHAR(tty) ((tty)->termios.c_cc[VSTART])
44 #define STOP_CHAR(tty) ((tty)->termios.c_cc[VSTOP])
45 #define SUSP_CHAR(tty) ((tty)->termios.c_cc[VSUSP])
46 #define EOL_CHAR(tty) ((tty)->termios.c_cc[VEOL])
47 #define REPRINT_CHAR(tty) ((tty)->termios.c_cc[VREPRINT])
48 #define DISCARD_CHAR(tty) ((tty)->termios.c_cc[VDISCARD])
49 #define WERASE_CHAR(tty) ((tty)->termios.c_cc[VWERASE])
50 #define LNEXT_CHAR(tty) ((tty)->termios.c_cc[VLNEXT])
51 #define EOL2_CHAR(tty) ((tty)->termios.c_cc[VEOL2])
52
53 #define _I_FLAG(tty, f) ((tty)->termios.c_iflag & (f))
54 #define _O_FLAG(tty, f) ((tty)->termios.c_oflag & (f))
55 #define _C_FLAG(tty, f) ((tty)->termios.c_cflag & (f))
56 #define _L_FLAG(tty, f) ((tty)->termios.c_lflag & (f))
57
58 #define I_IGNBRK(tty) _I_FLAG((tty), IGNBRK)
59 #define I_BRKINT(tty) _I_FLAG((tty), BRKINT)
60 #define I_IGNPAR(tty) _I_FLAG((tty), IGNPAR)
61 #define I_PARMRK(tty) _I_FLAG((tty), PARMRK)
62 #define I_INPCK(tty) _I_FLAG((tty), INPCK)
63 #define I_ISTRIP(tty) _I_FLAG((tty), ISTRIP)
64 #define I_INLCR(tty) _I_FLAG((tty), INLCR)
65 #define I_IGNCR(tty) _I_FLAG((tty), IGNCR)
66 #define I_ICRNL(tty) _I_FLAG((tty), ICRNL)
67 #define I_IUCLC(tty) _I_FLAG((tty), IUCLC)
68 #define I_IXON(tty) _I_FLAG((tty), IXON)
69 #define I_IXANY(tty) _I_FLAG((tty), IXANY)
70 #define I_IXOFF(tty) _I_FLAG((tty), IXOFF)
71 #define I_IMAXBEL(tty) _I_FLAG((tty), IMAXBEL)
72 #define I_IUTF8(tty) _I_FLAG((tty), IUTF8)
73
74 #define O_OPOST(tty) _O_FLAG((tty), OPOST)
75 #define O_OLCUC(tty) _O_FLAG((tty), OLCUC)
76 #define O_ONLCR(tty) _O_FLAG((tty), ONLCR)
77 #define O_OCRNL(tty) _O_FLAG((tty), OCRNL)
78 #define O_ONOCR(tty) _O_FLAG((tty), ONOCR)
79 #define O_ONLRET(tty) _O_FLAG((tty), ONLRET)
80 #define O_OFILL(tty) _O_FLAG((tty), OFILL)
81 #define O_OFDEL(tty) _O_FLAG((tty), OFDEL)
82 #define O_NLDLY(tty) _O_FLAG((tty), NLDLY)
83 #define O_CRDLY(tty) _O_FLAG((tty), CRDLY)
84 #define O_TABDLY(tty) _O_FLAG((tty), TABDLY)
85 #define O_BSDLY(tty) _O_FLAG((tty), BSDLY)
86 #define O_VTDLY(tty) _O_FLAG((tty), VTDLY)
87 #define O_FFDLY(tty) _O_FLAG((tty), FFDLY)
88
89 #define C_BAUD(tty) _C_FLAG((tty), CBAUD)
90 #define C_CSIZE(tty) _C_FLAG((tty), CSIZE)
91 #define C_CSTOPB(tty) _C_FLAG((tty), CSTOPB)
92 #define C_CREAD(tty) _C_FLAG((tty), CREAD)
93 #define C_PARENB(tty) _C_FLAG((tty), PARENB)
94 #define C_PARODD(tty) _C_FLAG((tty), PARODD)
95 #define C_HUPCL(tty) _C_FLAG((tty), HUPCL)
96 #define C_CLOCAL(tty) _C_FLAG((tty), CLOCAL)
97 #define C_CIBAUD(tty) _C_FLAG((tty), CIBAUD)
98 #define C_CRTSCTS(tty) _C_FLAG((tty), CRTSCTS)
99 #define C_CMSPAR(tty) _C_FLAG((tty), CMSPAR)
100
101 #define L_ISIG(tty) _L_FLAG((tty), ISIG)
102 #define L_ICANON(tty) _L_FLAG((tty), ICANON)
103 #define L_XCASE(tty) _L_FLAG((tty), XCASE)
104 #define L_ECHO(tty) _L_FLAG((tty), ECHO)
105 #define L_ECHOE(tty) _L_FLAG((tty), ECHOE)
106 #define L_ECHOK(tty) _L_FLAG((tty), ECHOK)
107 #define L_ECHONL(tty) _L_FLAG((tty), ECHONL)
108 #define L_NOFLSH(tty) _L_FLAG((tty), NOFLSH)
109 #define L_TOSTOP(tty) _L_FLAG((tty), TOSTOP)
110 #define L_ECHOCTL(tty) _L_FLAG((tty), ECHOCTL)
111 #define L_ECHOPRT(tty) _L_FLAG((tty), ECHOPRT)
112 #define L_ECHOKE(tty) _L_FLAG((tty), ECHOKE)
113 #define L_FLUSHO(tty) _L_FLAG((tty), FLUSHO)
114 #define L_PENDIN(tty) _L_FLAG((tty), PENDIN)
115 #define L_IEXTEN(tty) _L_FLAG((tty), IEXTEN)
116 #define L_EXTPROC(tty) _L_FLAG((tty), EXTPROC)
117
118 struct device;
119 struct signal_struct;
120 struct tty_operations;
121
122 /**
123 * struct tty_struct - state associated with a tty while open
124 *
125 * @kref: reference counting by tty_kref_get() and tty_kref_put(), reaching zero
126 * frees the structure
127 * @dev: class device or %NULL (e.g. ptys, serdev)
128 * @driver: &struct tty_driver operating this tty
129 * @ops: &struct tty_operations of @driver for this tty (open, close, etc.)
130 * @index: index of this tty (e.g. to construct @name like tty12)
131 * @ldisc_sem: protects line discipline changes (@ldisc) -- lock tty not pty
132 * @ldisc: the current line discipline for this tty (n_tty by default)
133 * @atomic_write_lock: protects against concurrent writers, i.e. locks
134 * @write_cnt, @write_buf and similar
135 * @legacy_mutex: leftover from history (BKL -> BTM -> @legacy_mutex),
136 * protecting several operations on this tty
137 * @throttle_mutex: protects against concurrent tty_throttle_safe() and
138 * tty_unthrottle_safe() (but not tty_unthrottle())
139 * @termios_rwsem: protects @termios and @termios_locked
140 * @winsize_mutex: protects @winsize
141 * @termios: termios for the current tty, copied from/to @driver.termios
142 * @termios_locked: locked termios (by %TIOCGLCKTRMIOS and %TIOCSLCKTRMIOS
143 * ioctls)
144 * @name: name of the tty constructed by tty_line_name() (e.g. ttyS3)
145 * @flags: bitwise OR of %TTY_THROTTLED, %TTY_IO_ERROR, ...
146 * @count: count of open processes, reaching zero cancels all the work for
147 * this tty and drops a @kref too (but does not free this tty)
148 * @winsize: size of the terminal "window" (cf. @winsize_mutex)
149 * @flow: flow settings grouped together
150 * @flow.lock: lock for @flow members
151 * @flow.stopped: tty stopped/started by stop_tty()/start_tty()
152 * @flow.tco_stopped: tty stopped/started by %TCOOFF/%TCOON ioctls (it has
153 * precedence over @flow.stopped)
154 * @ctrl: control settings grouped together
155 * @ctrl.lock: lock for @ctrl members
156 * @ctrl.pgrp: process group of this tty (setpgrp(2))
157 * @ctrl.session: session of this tty (setsid(2)). Writes are protected by both
158 * @ctrl.lock and @legacy_mutex, readers must use at least one of
159 * them.
160 * @ctrl.pktstatus: packet mode status (bitwise OR of %TIOCPKT_ constants)
161 * @ctrl.packet: packet mode enabled
162 * @hw_stopped: not controlled by the tty layer, under @driver's control for CTS
163 * handling
164 * @receive_room: bytes permitted to feed to @ldisc without any being lost
165 * @flow_change: controls behavior of throttling, see tty_throttle_safe() and
166 * tty_unthrottle_safe()
167 * @link: link to another pty (master -> slave and vice versa)
168 * @fasync: state for %O_ASYNC (for %SIGIO); managed by fasync_helper()
169 * @write_wait: concurrent writers are waiting in this queue until they are
170 * allowed to write
171 * @read_wait: readers wait for data in this queue
172 * @hangup_work: normally a work to perform a hangup (do_tty_hangup()); while
173 * freeing the tty, (re)used to release_one_tty()
174 * @disc_data: pointer to @ldisc's private data (e.g. to &struct n_tty_data)
175 * @driver_data: pointer to @driver's private data (e.g. &struct uart_state)
176 * @files_lock: protects @tty_files list
177 * @tty_files: list of (re)openers of this tty (i.e. linked &struct
178 * tty_file_private)
179 * @closing: when set during close, n_tty processes only START & STOP chars
180 * @write_buf: temporary buffer used during tty_write() to copy user data to
181 * @write_cnt: count of bytes written in tty_write() to @write_buf
182 * @SAK_work: if the tty has a pending do_SAK, it is queued here
183 * @port: persistent storage for this device (i.e. &struct tty_port)
184 *
185 * All of the state associated with a tty while the tty is open. Persistent
186 * storage for tty devices is referenced here as @port and is documented in
187 * &struct tty_port.
188 */
189 struct tty_struct {
190 struct kref kref;
191 int index;
192 struct device *dev;
193 struct tty_driver *driver;
194 struct tty_port *port;
195 const struct tty_operations *ops;
196
197 struct tty_ldisc *ldisc;
198 struct ld_semaphore ldisc_sem;
199
200 struct mutex atomic_write_lock;
201 struct mutex legacy_mutex;
202 struct mutex throttle_mutex;
203 struct rw_semaphore termios_rwsem;
204 struct mutex winsize_mutex;
205 struct ktermios termios, termios_locked;
206 char name[64];
207 unsigned long flags;
208 int count;
209 unsigned int receive_room;
210 struct winsize winsize;
211
212 struct {
213 spinlock_t lock;
214 bool stopped;
215 bool tco_stopped;
216 } flow;
217
218 struct {
219 struct pid *pgrp;
220 struct pid *session;
221 spinlock_t lock;
222 unsigned char pktstatus;
223 bool packet;
224 } ctrl;
225
226 bool hw_stopped;
227 bool closing;
228 int flow_change;
229
230 struct tty_struct *link;
231 struct fasync_struct *fasync;
232 wait_queue_head_t write_wait;
233 wait_queue_head_t read_wait;
234 struct work_struct hangup_work;
235 void *disc_data;
236 void *driver_data;
237 spinlock_t files_lock;
238 int write_cnt;
239 u8 *write_buf;
240
241 struct list_head tty_files;
242
243 #define N_TTY_BUF_SIZE 4096
244 struct work_struct SAK_work;
245
246 ANDROID_KABI_RESERVE(1);
247 ANDROID_KABI_RESERVE(2);
248 } __randomize_layout;
249
250 /* Each of a tty's open files has private_data pointing to tty_file_private */
251 struct tty_file_private {
252 struct tty_struct *tty;
253 struct file *file;
254 struct list_head list;
255 };
256
257 /**
258 * DOC: TTY Struct Flags
259 *
260 * These bits are used in the :c:member:`tty_struct.flags` field.
261 *
262 * So that interrupts won't be able to mess up the queues,
263 * copy_to_cooked must be atomic with respect to itself, as must
264 * tty->write. Thus, you must use the inline functions set_bit() and
265 * clear_bit() to make things atomic.
266 *
267 * TTY_THROTTLED
268 * Driver input is throttled. The ldisc should call
269 * :c:member:`tty_driver.unthrottle()` in order to resume reception when
270 * it is ready to process more data (at threshold min).
271 *
272 * TTY_IO_ERROR
273 * If set, causes all subsequent userspace read/write calls on the tty to
274 * fail, returning -%EIO. (May be no ldisc too.)
275 *
276 * TTY_OTHER_CLOSED
277 * Device is a pty and the other side has closed.
278 *
279 * TTY_EXCLUSIVE
280 * Exclusive open mode (a single opener).
281 *
282 * TTY_DO_WRITE_WAKEUP
283 * If set, causes the driver to call the
284 * :c:member:`tty_ldisc_ops.write_wakeup()` method in order to resume
285 * transmission when it can accept more data to transmit.
286 *
287 * TTY_LDISC_OPEN
288 * Indicates that a line discipline is open. For debugging purposes only.
289 *
290 * TTY_PTY_LOCK
291 * A flag private to pty code to implement %TIOCSPTLCK/%TIOCGPTLCK logic.
292 *
293 * TTY_NO_WRITE_SPLIT
294 * Prevent driver from splitting up writes into smaller chunks (preserve
295 * write boundaries to driver).
296 *
297 * TTY_HUPPED
298 * The TTY was hung up. This is set post :c:member:`tty_driver.hangup()`.
299 *
300 * TTY_HUPPING
301 * The TTY is in the process of hanging up to abort potential readers.
302 *
303 * TTY_LDISC_CHANGING
304 * Line discipline for this TTY is being changed. I/O should not block
305 * when this is set. Use tty_io_nonblock() to check.
306 *
307 * TTY_LDISC_HALTED
308 * Line discipline for this TTY was stopped. No work should be queued to
309 * this ldisc.
310 */
311 #define TTY_THROTTLED 0
312 #define TTY_IO_ERROR 1
313 #define TTY_OTHER_CLOSED 2
314 #define TTY_EXCLUSIVE 3
315 #define TTY_DO_WRITE_WAKEUP 5
316 #define TTY_LDISC_OPEN 11
317 #define TTY_PTY_LOCK 16
318 #define TTY_NO_WRITE_SPLIT 17
319 #define TTY_HUPPED 18
320 #define TTY_HUPPING 19
321 #define TTY_LDISC_CHANGING 20
322 #define TTY_LDISC_HALTED 22
323
tty_io_nonblock(struct tty_struct * tty,struct file * file)324 static inline bool tty_io_nonblock(struct tty_struct *tty, struct file *file)
325 {
326 return file->f_flags & O_NONBLOCK ||
327 test_bit(TTY_LDISC_CHANGING, &tty->flags);
328 }
329
tty_io_error(struct tty_struct * tty)330 static inline bool tty_io_error(struct tty_struct *tty)
331 {
332 return test_bit(TTY_IO_ERROR, &tty->flags);
333 }
334
tty_throttled(struct tty_struct * tty)335 static inline bool tty_throttled(struct tty_struct *tty)
336 {
337 return test_bit(TTY_THROTTLED, &tty->flags);
338 }
339
340 #ifdef CONFIG_TTY
341 void tty_kref_put(struct tty_struct *tty);
342 struct pid *tty_get_pgrp(struct tty_struct *tty);
343 void tty_vhangup_self(void);
344 void disassociate_ctty(int priv);
345 dev_t tty_devnum(struct tty_struct *tty);
346 void proc_clear_tty(struct task_struct *p);
347 struct tty_struct *get_current_tty(void);
348 /* tty_io.c */
349 int __init tty_init(void);
350 const char *tty_name(const struct tty_struct *tty);
351 struct tty_struct *tty_kopen_exclusive(dev_t device);
352 struct tty_struct *tty_kopen_shared(dev_t device);
353 void tty_kclose(struct tty_struct *tty);
354 int tty_dev_name_to_number(const char *name, dev_t *number);
355 #else
tty_kref_put(struct tty_struct * tty)356 static inline void tty_kref_put(struct tty_struct *tty)
357 { }
tty_get_pgrp(struct tty_struct * tty)358 static inline struct pid *tty_get_pgrp(struct tty_struct *tty)
359 { return NULL; }
tty_vhangup_self(void)360 static inline void tty_vhangup_self(void)
361 { }
disassociate_ctty(int priv)362 static inline void disassociate_ctty(int priv)
363 { }
tty_devnum(struct tty_struct * tty)364 static inline dev_t tty_devnum(struct tty_struct *tty)
365 { return 0; }
proc_clear_tty(struct task_struct * p)366 static inline void proc_clear_tty(struct task_struct *p)
367 { }
get_current_tty(void)368 static inline struct tty_struct *get_current_tty(void)
369 { return NULL; }
370 /* tty_io.c */
tty_init(void)371 static inline int __init tty_init(void)
372 { return 0; }
tty_name(const struct tty_struct * tty)373 static inline const char *tty_name(const struct tty_struct *tty)
374 { return "(none)"; }
tty_kopen_exclusive(dev_t device)375 static inline struct tty_struct *tty_kopen_exclusive(dev_t device)
376 { return ERR_PTR(-ENODEV); }
tty_kclose(struct tty_struct * tty)377 static inline void tty_kclose(struct tty_struct *tty)
378 { }
tty_dev_name_to_number(const char * name,dev_t * number)379 static inline int tty_dev_name_to_number(const char *name, dev_t *number)
380 { return -ENOTSUPP; }
381 #endif
382
383 extern struct ktermios tty_std_termios;
384
385 int vcs_init(void);
386
387 extern const struct class tty_class;
388
389 /**
390 * tty_kref_get - get a tty reference
391 * @tty: tty device
392 *
393 * Returns: a new reference to a tty object
394 *
395 * Locking: The caller must hold sufficient locks/counts to ensure that their
396 * existing reference cannot go away.
397 */
tty_kref_get(struct tty_struct * tty)398 static inline struct tty_struct *tty_kref_get(struct tty_struct *tty)
399 {
400 if (tty)
401 kref_get(&tty->kref);
402 return tty;
403 }
404
405 const char *tty_driver_name(const struct tty_struct *tty);
406 void tty_wait_until_sent(struct tty_struct *tty, long timeout);
407 void stop_tty(struct tty_struct *tty);
408 void start_tty(struct tty_struct *tty);
409 void tty_write_message(struct tty_struct *tty, char *msg);
410 int tty_send_xchar(struct tty_struct *tty, u8 ch);
411 int tty_put_char(struct tty_struct *tty, u8 c);
412 unsigned int tty_chars_in_buffer(struct tty_struct *tty);
413 unsigned int tty_write_room(struct tty_struct *tty);
414 void tty_driver_flush_buffer(struct tty_struct *tty);
415 void tty_unthrottle(struct tty_struct *tty);
416 bool tty_throttle_safe(struct tty_struct *tty);
417 bool tty_unthrottle_safe(struct tty_struct *tty);
418 int tty_do_resize(struct tty_struct *tty, struct winsize *ws);
419 int tty_get_icount(struct tty_struct *tty,
420 struct serial_icounter_struct *icount);
421 int tty_get_tiocm(struct tty_struct *tty);
422 int is_current_pgrp_orphaned(void);
423 void tty_hangup(struct tty_struct *tty);
424 void tty_vhangup(struct tty_struct *tty);
425 int tty_hung_up_p(struct file *filp);
426 void do_SAK(struct tty_struct *tty);
427 void __do_SAK(struct tty_struct *tty);
428 void no_tty(void);
429 speed_t tty_termios_baud_rate(const struct ktermios *termios);
430 void tty_termios_encode_baud_rate(struct ktermios *termios, speed_t ibaud,
431 speed_t obaud);
432 void tty_encode_baud_rate(struct tty_struct *tty, speed_t ibaud,
433 speed_t obaud);
434
435 /**
436 * tty_get_baud_rate - get tty bit rates
437 * @tty: tty to query
438 *
439 * Returns: the baud rate as an integer for this terminal
440 *
441 * Locking: The termios lock must be held by the caller.
442 */
tty_get_baud_rate(const struct tty_struct * tty)443 static inline speed_t tty_get_baud_rate(const struct tty_struct *tty)
444 {
445 return tty_termios_baud_rate(&tty->termios);
446 }
447
448 unsigned char tty_get_char_size(unsigned int cflag);
449 unsigned char tty_get_frame_size(unsigned int cflag);
450
451 void tty_termios_copy_hw(struct ktermios *new, const struct ktermios *old);
452 bool tty_termios_hw_change(const struct ktermios *a, const struct ktermios *b);
453 int tty_set_termios(struct tty_struct *tty, struct ktermios *kt);
454
455 void tty_wakeup(struct tty_struct *tty);
456
457 int tty_mode_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg);
458 int tty_perform_flush(struct tty_struct *tty, unsigned long arg);
459 struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx);
460 void tty_release_struct(struct tty_struct *tty, int idx);
461 void tty_init_termios(struct tty_struct *tty);
462 void tty_save_termios(struct tty_struct *tty);
463 int tty_standard_install(struct tty_driver *driver,
464 struct tty_struct *tty);
465
466 extern struct mutex tty_mutex;
467
468 /* n_tty.c */
469 void n_tty_inherit_ops(struct tty_ldisc_ops *ops);
470 #ifdef CONFIG_TTY
471 void __init n_tty_init(void);
472 #else
n_tty_init(void)473 static inline void n_tty_init(void) { }
474 #endif
475
476 /* tty_audit.c */
477 #ifdef CONFIG_AUDIT
478 void tty_audit_exit(void);
479 void tty_audit_fork(struct signal_struct *sig);
480 int tty_audit_push(void);
481 #else
tty_audit_exit(void)482 static inline void tty_audit_exit(void)
483 {
484 }
tty_audit_fork(struct signal_struct * sig)485 static inline void tty_audit_fork(struct signal_struct *sig)
486 {
487 }
tty_audit_push(void)488 static inline int tty_audit_push(void)
489 {
490 return 0;
491 }
492 #endif
493
494 /* tty_ioctl.c */
495 int n_tty_ioctl_helper(struct tty_struct *tty, unsigned int cmd,
496 unsigned long arg);
497
498 /* vt.c */
499
500 int vt_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg);
501
502 long vt_compat_ioctl(struct tty_struct *tty, unsigned int cmd,
503 unsigned long arg);
504
505 /* tty_mutex.c */
506 /* functions for preparation of BKL removal */
507 void tty_lock(struct tty_struct *tty);
508 int tty_lock_interruptible(struct tty_struct *tty);
509 void tty_unlock(struct tty_struct *tty);
510 void tty_lock_slave(struct tty_struct *tty);
511 void tty_unlock_slave(struct tty_struct *tty);
512 void tty_set_lock_subclass(struct tty_struct *tty);
513
514 #endif
515