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_buffer.h>
10 #include <linux/tty_driver.h>
11 #include <linux/tty_ldisc.h>
12 #include <linux/tty_port.h>
13 #include <linux/mutex.h>
14 #include <linux/tty_flags.h>
15 #include <uapi/linux/tty.h>
16 #include <linux/rwsem.h>
17 #include <linux/llist.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, see also @flow.unused
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 * @flow.unused: alignment for Alpha, so that no members other than @flow.* are
155 * modified by the same 64b word store. The @flow's __aligned is
156 * there for the very same reason.
157 * @ctrl: control settings grouped together, see also @ctrl.unused
158 * @ctrl.lock: lock for @ctrl members
159 * @ctrl.pgrp: process group of this tty (setpgrp(2))
160 * @ctrl.session: session of this tty (setsid(2)). Writes are protected by both
161 * @ctrl.lock and @legacy_mutex, readers must use at least one of
162 * them.
163 * @ctrl.pktstatus: packet mode status (bitwise OR of %TIOCPKT_ constants)
164 * @ctrl.packet: packet mode enabled
165 * @ctrl.unused: alignment for Alpha, see @flow.unused for explanation
166 * @hw_stopped: not controlled by the tty layer, under @driver's control for CTS
167 * handling
168 * @receive_room: bytes permitted to feed to @ldisc without any being lost
169 * @flow_change: controls behavior of throttling, see tty_throttle_safe() and
170 * tty_unthrottle_safe()
171 * @link: link to another pty (master -> slave and vice versa)
172 * @fasync: state for %O_ASYNC (for %SIGIO); managed by fasync_helper()
173 * @write_wait: concurrent writers are waiting in this queue until they are
174 * allowed to write
175 * @read_wait: readers wait for data in this queue
176 * @hangup_work: normally a work to perform a hangup (do_tty_hangup()); while
177 * freeing the tty, (re)used to release_one_tty()
178 * @disc_data: pointer to @ldisc's private data (e.g. to &struct n_tty_data)
179 * @driver_data: pointer to @driver's private data (e.g. &struct uart_state)
180 * @files_lock: protects @tty_files list
181 * @tty_files: list of (re)openers of this tty (i.e. linked &struct
182 * tty_file_private)
183 * @closing: when set during close, n_tty processes only START & STOP chars
184 * @write_buf: temporary buffer used during tty_write() to copy user data to
185 * @write_cnt: count of bytes written in tty_write() to @write_buf
186 * @SAK_work: if the tty has a pending do_SAK, it is queued here
187 * @port: persistent storage for this device (i.e. &struct tty_port)
188 *
189 * All of the state associated with a tty while the tty is open. Persistent
190 * storage for tty devices is referenced here as @port and is documented in
191 * &struct tty_port.
192 */
193 struct tty_struct {
194 struct kref kref;
195 int index;
196 struct device *dev;
197 struct tty_driver *driver;
198 struct tty_port *port;
199 const struct tty_operations *ops;
200
201 struct tty_ldisc *ldisc;
202 struct ld_semaphore ldisc_sem;
203
204 struct mutex atomic_write_lock;
205 struct mutex legacy_mutex;
206 struct mutex throttle_mutex;
207 struct rw_semaphore termios_rwsem;
208 struct mutex winsize_mutex;
209 struct ktermios termios, termios_locked;
210 char name[64];
211 unsigned long flags;
212 int count;
213 unsigned int receive_room;
214 struct winsize winsize;
215
216 struct {
217 spinlock_t lock;
218 bool stopped;
219 bool tco_stopped;
220 unsigned long unused[0];
221 } __aligned(sizeof(unsigned long)) flow;
222
223 struct {
224 struct pid *pgrp;
225 struct pid *session;
226 spinlock_t lock;
227 unsigned char pktstatus;
228 bool packet;
229 unsigned long unused[0];
230 } __aligned(sizeof(unsigned long)) ctrl;
231
232 bool hw_stopped;
233 bool closing;
234 int flow_change;
235
236 struct tty_struct *link;
237 struct fasync_struct *fasync;
238 wait_queue_head_t write_wait;
239 wait_queue_head_t read_wait;
240 struct work_struct hangup_work;
241 void *disc_data;
242 void *driver_data;
243 spinlock_t files_lock;
244 int write_cnt;
245 unsigned char *write_buf;
246
247 struct list_head tty_files;
248
249 #define N_TTY_BUF_SIZE 4096
250 struct work_struct SAK_work;
251 } __randomize_layout;
252
253 /* Each of a tty's open files has private_data pointing to tty_file_private */
254 struct tty_file_private {
255 struct tty_struct *tty;
256 struct file *file;
257 struct list_head list;
258 };
259
260 /**
261 * DOC: TTY Struct Flags
262 *
263 * These bits are used in the :c:member:`tty_struct.flags` field.
264 *
265 * So that interrupts won't be able to mess up the queues,
266 * copy_to_cooked must be atomic with respect to itself, as must
267 * tty->write. Thus, you must use the inline functions set_bit() and
268 * clear_bit() to make things atomic.
269 *
270 * TTY_THROTTLED
271 * Driver input is throttled. The ldisc should call
272 * :c:member:`tty_driver.unthrottle()` in order to resume reception when
273 * it is ready to process more data (at threshold min).
274 *
275 * TTY_IO_ERROR
276 * If set, causes all subsequent userspace read/write calls on the tty to
277 * fail, returning -%EIO. (May be no ldisc too.)
278 *
279 * TTY_OTHER_CLOSED
280 * Device is a pty and the other side has closed.
281 *
282 * TTY_EXCLUSIVE
283 * Exclusive open mode (a single opener).
284 *
285 * TTY_DO_WRITE_WAKEUP
286 * If set, causes the driver to call the
287 * :c:member:`tty_ldisc_ops.write_wakeup()` method in order to resume
288 * transmission when it can accept more data to transmit.
289 *
290 * TTY_LDISC_OPEN
291 * Indicates that a line discipline is open. For debugging purposes only.
292 *
293 * TTY_PTY_LOCK
294 * A flag private to pty code to implement %TIOCSPTLCK/%TIOCGPTLCK logic.
295 *
296 * TTY_NO_WRITE_SPLIT
297 * Prevent driver from splitting up writes into smaller chunks (preserve
298 * write boundaries to driver).
299 *
300 * TTY_HUPPED
301 * The TTY was hung up. This is set post :c:member:`tty_driver.hangup()`.
302 *
303 * TTY_HUPPING
304 * The TTY is in the process of hanging up to abort potential readers.
305 *
306 * TTY_LDISC_CHANGING
307 * Line discipline for this TTY is being changed. I/O should not block
308 * when this is set. Use tty_io_nonblock() to check.
309 *
310 * TTY_LDISC_HALTED
311 * Line discipline for this TTY was stopped. No work should be queued to
312 * this ldisc.
313 */
314 #define TTY_THROTTLED 0
315 #define TTY_IO_ERROR 1
316 #define TTY_OTHER_CLOSED 2
317 #define TTY_EXCLUSIVE 3
318 #define TTY_DO_WRITE_WAKEUP 5
319 #define TTY_LDISC_OPEN 11
320 #define TTY_PTY_LOCK 16
321 #define TTY_NO_WRITE_SPLIT 17
322 #define TTY_HUPPED 18
323 #define TTY_HUPPING 19
324 #define TTY_LDISC_CHANGING 20
325 #define TTY_LDISC_HALTED 22
326
tty_io_nonblock(struct tty_struct * tty,struct file * file)327 static inline bool tty_io_nonblock(struct tty_struct *tty, struct file *file)
328 {
329 return file->f_flags & O_NONBLOCK ||
330 test_bit(TTY_LDISC_CHANGING, &tty->flags);
331 }
332
tty_io_error(struct tty_struct * tty)333 static inline bool tty_io_error(struct tty_struct *tty)
334 {
335 return test_bit(TTY_IO_ERROR, &tty->flags);
336 }
337
tty_throttled(struct tty_struct * tty)338 static inline bool tty_throttled(struct tty_struct *tty)
339 {
340 return test_bit(TTY_THROTTLED, &tty->flags);
341 }
342
343 #ifdef CONFIG_TTY
344 void tty_kref_put(struct tty_struct *tty);
345 struct pid *tty_get_pgrp(struct tty_struct *tty);
346 void tty_vhangup_self(void);
347 void disassociate_ctty(int priv);
348 dev_t tty_devnum(struct tty_struct *tty);
349 void proc_clear_tty(struct task_struct *p);
350 struct tty_struct *get_current_tty(void);
351 /* tty_io.c */
352 int __init tty_init(void);
353 const char *tty_name(const struct tty_struct *tty);
354 struct tty_struct *tty_kopen_exclusive(dev_t device);
355 struct tty_struct *tty_kopen_shared(dev_t device);
356 void tty_kclose(struct tty_struct *tty);
357 int tty_dev_name_to_number(const char *name, dev_t *number);
358 #else
tty_kref_put(struct tty_struct * tty)359 static inline void tty_kref_put(struct tty_struct *tty)
360 { }
tty_get_pgrp(struct tty_struct * tty)361 static inline struct pid *tty_get_pgrp(struct tty_struct *tty)
362 { return NULL; }
tty_vhangup_self(void)363 static inline void tty_vhangup_self(void)
364 { }
disassociate_ctty(int priv)365 static inline void disassociate_ctty(int priv)
366 { }
tty_devnum(struct tty_struct * tty)367 static inline dev_t tty_devnum(struct tty_struct *tty)
368 { return 0; }
proc_clear_tty(struct task_struct * p)369 static inline void proc_clear_tty(struct task_struct *p)
370 { }
get_current_tty(void)371 static inline struct tty_struct *get_current_tty(void)
372 { return NULL; }
373 /* tty_io.c */
tty_init(void)374 static inline int __init tty_init(void)
375 { return 0; }
tty_name(const struct tty_struct * tty)376 static inline const char *tty_name(const struct tty_struct *tty)
377 { return "(none)"; }
tty_kopen_exclusive(dev_t device)378 static inline struct tty_struct *tty_kopen_exclusive(dev_t device)
379 { return ERR_PTR(-ENODEV); }
tty_kclose(struct tty_struct * tty)380 static inline void tty_kclose(struct tty_struct *tty)
381 { }
tty_dev_name_to_number(const char * name,dev_t * number)382 static inline int tty_dev_name_to_number(const char *name, dev_t *number)
383 { return -ENOTSUPP; }
384 #endif
385
386 extern struct ktermios tty_std_termios;
387
388 int vcs_init(void);
389
390 extern const struct class tty_class;
391
392 /**
393 * tty_kref_get - get a tty reference
394 * @tty: tty device
395 *
396 * Return a new reference to a tty object. The caller must hold
397 * sufficient locks/counts to ensure that their existing reference cannot
398 * go away
399 */
400
tty_kref_get(struct tty_struct * tty)401 static inline struct tty_struct *tty_kref_get(struct tty_struct *tty)
402 {
403 if (tty)
404 kref_get(&tty->kref);
405 return tty;
406 }
407
408 const char *tty_driver_name(const struct tty_struct *tty);
409 void tty_wait_until_sent(struct tty_struct *tty, long timeout);
410 void stop_tty(struct tty_struct *tty);
411 void start_tty(struct tty_struct *tty);
412 void tty_write_message(struct tty_struct *tty, char *msg);
413 int tty_send_xchar(struct tty_struct *tty, char ch);
414 int tty_put_char(struct tty_struct *tty, unsigned char c);
415 unsigned int tty_chars_in_buffer(struct tty_struct *tty);
416 unsigned int tty_write_room(struct tty_struct *tty);
417 void tty_driver_flush_buffer(struct tty_struct *tty);
418 void tty_unthrottle(struct tty_struct *tty);
419 int tty_throttle_safe(struct tty_struct *tty);
420 int tty_unthrottle_safe(struct tty_struct *tty);
421 int tty_do_resize(struct tty_struct *tty, struct winsize *ws);
422 int tty_get_icount(struct tty_struct *tty,
423 struct serial_icounter_struct *icount);
424 int is_current_pgrp_orphaned(void);
425 void tty_hangup(struct tty_struct *tty);
426 void tty_vhangup(struct tty_struct *tty);
427 int tty_hung_up_p(struct file *filp);
428 void do_SAK(struct tty_struct *tty);
429 void __do_SAK(struct tty_struct *tty);
430 void no_tty(void);
431 speed_t tty_termios_baud_rate(const struct ktermios *termios);
432 void tty_termios_encode_baud_rate(struct ktermios *termios, speed_t ibaud,
433 speed_t obaud);
434 void tty_encode_baud_rate(struct tty_struct *tty, speed_t ibaud,
435 speed_t obaud);
436
437 /**
438 * tty_get_baud_rate - get tty bit rates
439 * @tty: tty to query
440 *
441 * Returns the baud rate as an integer for this terminal. The
442 * termios lock must be held by the caller and the terminal bit
443 * flags may be updated.
444 *
445 * Locking: none
446 */
tty_get_baud_rate(struct tty_struct * tty)447 static inline speed_t tty_get_baud_rate(struct tty_struct *tty)
448 {
449 return tty_termios_baud_rate(&tty->termios);
450 }
451
452 unsigned char tty_get_char_size(unsigned int cflag);
453 unsigned char tty_get_frame_size(unsigned int cflag);
454
455 void tty_termios_copy_hw(struct ktermios *new, const struct ktermios *old);
456 bool tty_termios_hw_change(const struct ktermios *a, const struct ktermios *b);
457 int tty_set_termios(struct tty_struct *tty, struct ktermios *kt);
458
459 void tty_wakeup(struct tty_struct *tty);
460
461 int tty_mode_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg);
462 int tty_perform_flush(struct tty_struct *tty, unsigned long arg);
463 struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx);
464 void tty_release_struct(struct tty_struct *tty, int idx);
465 void tty_init_termios(struct tty_struct *tty);
466 void tty_save_termios(struct tty_struct *tty);
467 int tty_standard_install(struct tty_driver *driver,
468 struct tty_struct *tty);
469
470 extern struct mutex tty_mutex;
471
472 /* n_tty.c */
473 void n_tty_inherit_ops(struct tty_ldisc_ops *ops);
474 #ifdef CONFIG_TTY
475 void __init n_tty_init(void);
476 #else
n_tty_init(void)477 static inline void n_tty_init(void) { }
478 #endif
479
480 /* tty_audit.c */
481 #ifdef CONFIG_AUDIT
482 void tty_audit_exit(void);
483 void tty_audit_fork(struct signal_struct *sig);
484 int tty_audit_push(void);
485 #else
tty_audit_exit(void)486 static inline void tty_audit_exit(void)
487 {
488 }
tty_audit_fork(struct signal_struct * sig)489 static inline void tty_audit_fork(struct signal_struct *sig)
490 {
491 }
tty_audit_push(void)492 static inline int tty_audit_push(void)
493 {
494 return 0;
495 }
496 #endif
497
498 /* tty_ioctl.c */
499 int n_tty_ioctl_helper(struct tty_struct *tty, unsigned int cmd,
500 unsigned long arg);
501
502 /* vt.c */
503
504 int vt_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg);
505
506 long vt_compat_ioctl(struct tty_struct *tty, unsigned int cmd,
507 unsigned long arg);
508
509 /* tty_mutex.c */
510 /* functions for preparation of BKL removal */
511 void tty_lock(struct tty_struct *tty);
512 int tty_lock_interruptible(struct tty_struct *tty);
513 void tty_unlock(struct tty_struct *tty);
514 void tty_lock_slave(struct tty_struct *tty);
515 void tty_unlock_slave(struct tty_struct *tty);
516 void tty_set_lock_subclass(struct tty_struct *tty);
517
518 #endif
519