xref: /openbmc/linux/include/linux/tty.h (revision 5f48ed2e)
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/mutex.h>
12 #include <linux/tty_flags.h>
13 #include <linux/seq_file.h>
14 #include <uapi/linux/tty.h>
15 #include <linux/rwsem.h>
16 #include <linux/llist.h>
17 
18 
19 /*
20  * (Note: the *_driver.minor_start values 1, 64, 128, 192 are
21  * hardcoded at present.)
22  */
23 #define NR_UNIX98_PTY_DEFAULT	4096      /* Default maximum for Unix98 ptys */
24 #define NR_UNIX98_PTY_RESERVE	1024	  /* Default reserve for main devpts */
25 #define NR_UNIX98_PTY_MAX	(1 << MINORBITS) /* Absolute limit */
26 
27 /*
28  * This character is the same as _POSIX_VDISABLE: it cannot be used as
29  * a c_cc[] character, but indicates that a particular special character
30  * isn't in use (eg VINTR has no character etc)
31  */
32 #define __DISABLED_CHAR '\0'
33 
34 struct tty_buffer {
35 	union {
36 		struct tty_buffer *next;
37 		struct llist_node free;
38 	};
39 	int used;
40 	int size;
41 	int commit;
42 	int read;
43 	int flags;
44 	/* Data points here */
45 	unsigned long data[];
46 };
47 
48 /* Values for .flags field of tty_buffer */
49 #define TTYB_NORMAL	1	/* buffer has no flags buffer */
50 
51 static inline unsigned char *char_buf_ptr(struct tty_buffer *b, int ofs)
52 {
53 	return ((unsigned char *)b->data) + ofs;
54 }
55 
56 static inline char *flag_buf_ptr(struct tty_buffer *b, int ofs)
57 {
58 	return (char *)char_buf_ptr(b, ofs) + b->size;
59 }
60 
61 struct tty_bufhead {
62 	struct tty_buffer *head;	/* Queue head */
63 	struct work_struct work;
64 	struct mutex	   lock;
65 	atomic_t	   priority;
66 	struct tty_buffer sentinel;
67 	struct llist_head free;		/* Free queue head */
68 	atomic_t	   mem_used;    /* In-use buffers excluding free list */
69 	int		   mem_limit;
70 	struct tty_buffer *tail;	/* Active buffer */
71 };
72 /*
73  * When a break, frame error, or parity error happens, these codes are
74  * stuffed into the flags buffer.
75  */
76 #define TTY_NORMAL	0
77 #define TTY_BREAK	1
78 #define TTY_FRAME	2
79 #define TTY_PARITY	3
80 #define TTY_OVERRUN	4
81 
82 #define INTR_CHAR(tty) ((tty)->termios.c_cc[VINTR])
83 #define QUIT_CHAR(tty) ((tty)->termios.c_cc[VQUIT])
84 #define ERASE_CHAR(tty) ((tty)->termios.c_cc[VERASE])
85 #define KILL_CHAR(tty) ((tty)->termios.c_cc[VKILL])
86 #define EOF_CHAR(tty) ((tty)->termios.c_cc[VEOF])
87 #define TIME_CHAR(tty) ((tty)->termios.c_cc[VTIME])
88 #define MIN_CHAR(tty) ((tty)->termios.c_cc[VMIN])
89 #define SWTC_CHAR(tty) ((tty)->termios.c_cc[VSWTC])
90 #define START_CHAR(tty) ((tty)->termios.c_cc[VSTART])
91 #define STOP_CHAR(tty) ((tty)->termios.c_cc[VSTOP])
92 #define SUSP_CHAR(tty) ((tty)->termios.c_cc[VSUSP])
93 #define EOL_CHAR(tty) ((tty)->termios.c_cc[VEOL])
94 #define REPRINT_CHAR(tty) ((tty)->termios.c_cc[VREPRINT])
95 #define DISCARD_CHAR(tty) ((tty)->termios.c_cc[VDISCARD])
96 #define WERASE_CHAR(tty) ((tty)->termios.c_cc[VWERASE])
97 #define LNEXT_CHAR(tty)	((tty)->termios.c_cc[VLNEXT])
98 #define EOL2_CHAR(tty) ((tty)->termios.c_cc[VEOL2])
99 
100 #define _I_FLAG(tty, f)	((tty)->termios.c_iflag & (f))
101 #define _O_FLAG(tty, f)	((tty)->termios.c_oflag & (f))
102 #define _C_FLAG(tty, f)	((tty)->termios.c_cflag & (f))
103 #define _L_FLAG(tty, f)	((tty)->termios.c_lflag & (f))
104 
105 #define I_IGNBRK(tty)	_I_FLAG((tty), IGNBRK)
106 #define I_BRKINT(tty)	_I_FLAG((tty), BRKINT)
107 #define I_IGNPAR(tty)	_I_FLAG((tty), IGNPAR)
108 #define I_PARMRK(tty)	_I_FLAG((tty), PARMRK)
109 #define I_INPCK(tty)	_I_FLAG((tty), INPCK)
110 #define I_ISTRIP(tty)	_I_FLAG((tty), ISTRIP)
111 #define I_INLCR(tty)	_I_FLAG((tty), INLCR)
112 #define I_IGNCR(tty)	_I_FLAG((tty), IGNCR)
113 #define I_ICRNL(tty)	_I_FLAG((tty), ICRNL)
114 #define I_IUCLC(tty)	_I_FLAG((tty), IUCLC)
115 #define I_IXON(tty)	_I_FLAG((tty), IXON)
116 #define I_IXANY(tty)	_I_FLAG((tty), IXANY)
117 #define I_IXOFF(tty)	_I_FLAG((tty), IXOFF)
118 #define I_IMAXBEL(tty)	_I_FLAG((tty), IMAXBEL)
119 #define I_IUTF8(tty)	_I_FLAG((tty), IUTF8)
120 
121 #define O_OPOST(tty)	_O_FLAG((tty), OPOST)
122 #define O_OLCUC(tty)	_O_FLAG((tty), OLCUC)
123 #define O_ONLCR(tty)	_O_FLAG((tty), ONLCR)
124 #define O_OCRNL(tty)	_O_FLAG((tty), OCRNL)
125 #define O_ONOCR(tty)	_O_FLAG((tty), ONOCR)
126 #define O_ONLRET(tty)	_O_FLAG((tty), ONLRET)
127 #define O_OFILL(tty)	_O_FLAG((tty), OFILL)
128 #define O_OFDEL(tty)	_O_FLAG((tty), OFDEL)
129 #define O_NLDLY(tty)	_O_FLAG((tty), NLDLY)
130 #define O_CRDLY(tty)	_O_FLAG((tty), CRDLY)
131 #define O_TABDLY(tty)	_O_FLAG((tty), TABDLY)
132 #define O_BSDLY(tty)	_O_FLAG((tty), BSDLY)
133 #define O_VTDLY(tty)	_O_FLAG((tty), VTDLY)
134 #define O_FFDLY(tty)	_O_FLAG((tty), FFDLY)
135 
136 #define C_BAUD(tty)	_C_FLAG((tty), CBAUD)
137 #define C_CSIZE(tty)	_C_FLAG((tty), CSIZE)
138 #define C_CSTOPB(tty)	_C_FLAG((tty), CSTOPB)
139 #define C_CREAD(tty)	_C_FLAG((tty), CREAD)
140 #define C_PARENB(tty)	_C_FLAG((tty), PARENB)
141 #define C_PARODD(tty)	_C_FLAG((tty), PARODD)
142 #define C_HUPCL(tty)	_C_FLAG((tty), HUPCL)
143 #define C_CLOCAL(tty)	_C_FLAG((tty), CLOCAL)
144 #define C_CIBAUD(tty)	_C_FLAG((tty), CIBAUD)
145 #define C_CRTSCTS(tty)	_C_FLAG((tty), CRTSCTS)
146 #define C_CMSPAR(tty)	_C_FLAG((tty), CMSPAR)
147 
148 #define L_ISIG(tty)	_L_FLAG((tty), ISIG)
149 #define L_ICANON(tty)	_L_FLAG((tty), ICANON)
150 #define L_XCASE(tty)	_L_FLAG((tty), XCASE)
151 #define L_ECHO(tty)	_L_FLAG((tty), ECHO)
152 #define L_ECHOE(tty)	_L_FLAG((tty), ECHOE)
153 #define L_ECHOK(tty)	_L_FLAG((tty), ECHOK)
154 #define L_ECHONL(tty)	_L_FLAG((tty), ECHONL)
155 #define L_NOFLSH(tty)	_L_FLAG((tty), NOFLSH)
156 #define L_TOSTOP(tty)	_L_FLAG((tty), TOSTOP)
157 #define L_ECHOCTL(tty)	_L_FLAG((tty), ECHOCTL)
158 #define L_ECHOPRT(tty)	_L_FLAG((tty), ECHOPRT)
159 #define L_ECHOKE(tty)	_L_FLAG((tty), ECHOKE)
160 #define L_FLUSHO(tty)	_L_FLAG((tty), FLUSHO)
161 #define L_PENDIN(tty)	_L_FLAG((tty), PENDIN)
162 #define L_IEXTEN(tty)	_L_FLAG((tty), IEXTEN)
163 #define L_EXTPROC(tty)	_L_FLAG((tty), EXTPROC)
164 
165 struct device;
166 struct signal_struct;
167 
168 /*
169  * Port level information. Each device keeps its own port level information
170  * so provide a common structure for those ports wanting to use common support
171  * routines.
172  *
173  * The tty port has a different lifetime to the tty so must be kept apart.
174  * In addition be careful as tty -> port mappings are valid for the life
175  * of the tty object but in many cases port -> tty mappings are valid only
176  * until a hangup so don't use the wrong path.
177  */
178 
179 struct tty_port;
180 
181 struct tty_port_operations {
182 	/* Return 1 if the carrier is raised */
183 	int (*carrier_raised)(struct tty_port *port);
184 	/* Control the DTR line */
185 	void (*dtr_rts)(struct tty_port *port, int raise);
186 	/* Called when the last close completes or a hangup finishes
187 	   IFF the port was initialized. Do not use to free resources. Called
188 	   under the port mutex to serialize against activate/shutdowns */
189 	void (*shutdown)(struct tty_port *port);
190 	/* Called under the port mutex from tty_port_open, serialized using
191 	   the port mutex */
192         /* FIXME: long term getting the tty argument *out* of this would be
193            good for consoles */
194 	int (*activate)(struct tty_port *port, struct tty_struct *tty);
195 	/* Called on the final put of a port */
196 	void (*destruct)(struct tty_port *port);
197 };
198 
199 struct tty_port_client_operations {
200 	int (*receive_buf)(struct tty_port *port, const unsigned char *, const unsigned char *, size_t);
201 	void (*write_wakeup)(struct tty_port *port);
202 };
203 
204 extern const struct tty_port_client_operations tty_port_default_client_ops;
205 
206 struct tty_port {
207 	struct tty_bufhead	buf;		/* Locked internally */
208 	struct tty_struct	*tty;		/* Back pointer */
209 	struct tty_struct	*itty;		/* internal back ptr */
210 	const struct tty_port_operations *ops;	/* Port operations */
211 	const struct tty_port_client_operations *client_ops; /* Port client operations */
212 	spinlock_t		lock;		/* Lock protecting tty field */
213 	int			blocked_open;	/* Waiting to open */
214 	int			count;		/* Usage count */
215 	wait_queue_head_t	open_wait;	/* Open waiters */
216 	wait_queue_head_t	delta_msr_wait;	/* Modem status change */
217 	unsigned long		flags;		/* User TTY flags ASYNC_ */
218 	unsigned long		iflags;		/* Internal flags TTY_PORT_ */
219 	unsigned char		console:1;	/* port is a console */
220 	struct mutex		mutex;		/* Locking */
221 	struct mutex		buf_mutex;	/* Buffer alloc lock */
222 	unsigned char		*xmit_buf;	/* Optional buffer */
223 	unsigned int		close_delay;	/* Close port delay */
224 	unsigned int		closing_wait;	/* Delay for output */
225 	int			drain_delay;	/* Set to zero if no pure time
226 						   based drain is needed else
227 						   set to size of fifo */
228 	struct kref		kref;		/* Ref counter */
229 	void 			*client_data;
230 };
231 
232 /* tty_port::iflags bits -- use atomic bit ops */
233 #define TTY_PORT_INITIALIZED	0	/* device is initialized */
234 #define TTY_PORT_SUSPENDED	1	/* device is suspended */
235 #define TTY_PORT_ACTIVE		2	/* device is open */
236 
237 /*
238  * uart drivers: use the uart_port::status field and the UPSTAT_* defines
239  * for s/w-based flow control steering and carrier detection status
240  */
241 #define TTY_PORT_CTS_FLOW	3	/* h/w flow control enabled */
242 #define TTY_PORT_CHECK_CD	4	/* carrier detect enabled */
243 #define TTY_PORT_KOPENED	5	/* device exclusively opened by
244 					   kernel */
245 
246 struct tty_operations;
247 
248 /**
249  * struct tty_struct - state associated with a tty while open
250  *
251  * @flow.lock: lock for flow members
252  * @flow.stopped: tty stopped/started by tty_stop/tty_start
253  * @flow.tco_stopped: tty stopped/started by TCOOFF/TCOON ioctls (it has
254  *		      precedense over @flow.stopped)
255  * @flow.unused: alignment for Alpha, so that no members other than @flow.* are
256  *		 modified by the same 64b word store. The @flow's __aligned is
257  *		 there for the very same reason.
258  * @ctrl.lock: lock for ctrl members
259  * @ctrl.pgrp: process group of this tty (setpgrp(2))
260  * @ctrl.session: session of this tty (setsid(2)). Writes are protected by both
261  *		  @ctrl.lock and legacy mutex, readers must use at least one of
262  *		  them.
263  * @ctrl.pktstatus: packet mode status (bitwise OR of TIOCPKT_* constants)
264  * @ctrl.packet: packet mode enabled
265  *
266  * All of the state associated with a tty while the tty is open. Persistent
267  * storage for tty devices is referenced here as @port in struct tty_port.
268  */
269 struct tty_struct {
270 	int	magic;
271 	struct kref kref;
272 	struct device *dev;	/* class device or NULL (e.g. ptys, serdev) */
273 	struct tty_driver *driver;
274 	const struct tty_operations *ops;
275 	int index;
276 
277 	/* Protects ldisc changes: Lock tty not pty */
278 	struct ld_semaphore ldisc_sem;
279 	struct tty_ldisc *ldisc;
280 
281 	struct mutex atomic_write_lock;
282 	struct mutex legacy_mutex;
283 	struct mutex throttle_mutex;
284 	struct rw_semaphore termios_rwsem;
285 	struct mutex winsize_mutex;
286 	/* Termios values are protected by the termios rwsem */
287 	struct ktermios termios, termios_locked;
288 	char name[64];
289 	unsigned long flags;
290 	int count;
291 	struct winsize winsize;		/* winsize_mutex */
292 
293 	struct {
294 		spinlock_t lock;
295 		bool stopped;
296 		bool tco_stopped;
297 		unsigned long unused[0];
298 	} __aligned(sizeof(unsigned long)) flow;
299 
300 	struct {
301 		spinlock_t lock;
302 		struct pid *pgrp;
303 		struct pid *session;
304 		unsigned char pktstatus;
305 		bool packet;
306 		unsigned long unused[0];
307 	} __aligned(sizeof(unsigned long)) ctrl;
308 
309 	int hw_stopped;
310 	unsigned int receive_room;	/* Bytes free for queue */
311 	int flow_change;
312 
313 	struct tty_struct *link;
314 	struct fasync_struct *fasync;
315 	wait_queue_head_t write_wait;
316 	wait_queue_head_t read_wait;
317 	struct work_struct hangup_work;
318 	void *disc_data;
319 	void *driver_data;
320 	spinlock_t files_lock;		/* protects tty_files list */
321 	struct list_head tty_files;
322 
323 #define N_TTY_BUF_SIZE 4096
324 
325 	int closing;
326 	unsigned char *write_buf;
327 	int write_cnt;
328 	/* If the tty has a pending do_SAK, queue it here - akpm */
329 	struct work_struct SAK_work;
330 	struct tty_port *port;
331 } __randomize_layout;
332 
333 /* Each of a tty's open files has private_data pointing to tty_file_private */
334 struct tty_file_private {
335 	struct tty_struct *tty;
336 	struct file *file;
337 	struct list_head list;
338 };
339 
340 /* tty magic number */
341 #define TTY_MAGIC		0x5401
342 
343 /*
344  * These bits are used in the flags field of the tty structure.
345  *
346  * So that interrupts won't be able to mess up the queues,
347  * copy_to_cooked must be atomic with respect to itself, as must
348  * tty->write.  Thus, you must use the inline functions set_bit() and
349  * clear_bit() to make things atomic.
350  */
351 #define TTY_THROTTLED 		0	/* Call unthrottle() at threshold min */
352 #define TTY_IO_ERROR 		1	/* Cause an I/O error (may be no ldisc too) */
353 #define TTY_OTHER_CLOSED 	2	/* Other side (if any) has closed */
354 #define TTY_EXCLUSIVE 		3	/* Exclusive open mode */
355 #define TTY_DO_WRITE_WAKEUP 	5	/* Call write_wakeup after queuing new */
356 #define TTY_LDISC_OPEN	 	11	/* Line discipline is open */
357 #define TTY_PTY_LOCK 		16	/* pty private */
358 #define TTY_NO_WRITE_SPLIT 	17	/* Preserve write boundaries to driver */
359 #define TTY_HUPPED 		18	/* Post driver->hangup() */
360 #define TTY_HUPPING		19	/* Hangup in progress */
361 #define TTY_LDISC_CHANGING	20	/* Change pending - non-block IO */
362 #define TTY_LDISC_HALTED	22	/* Line discipline is halted */
363 
364 static inline bool tty_io_nonblock(struct tty_struct *tty, struct file *file)
365 {
366 	return file->f_flags & O_NONBLOCK ||
367 		test_bit(TTY_LDISC_CHANGING, &tty->flags);
368 }
369 
370 static inline bool tty_io_error(struct tty_struct *tty)
371 {
372 	return test_bit(TTY_IO_ERROR, &tty->flags);
373 }
374 
375 static inline bool tty_throttled(struct tty_struct *tty)
376 {
377 	return test_bit(TTY_THROTTLED, &tty->flags);
378 }
379 
380 #ifdef CONFIG_TTY
381 extern void tty_kref_put(struct tty_struct *tty);
382 extern struct pid *tty_get_pgrp(struct tty_struct *tty);
383 extern void tty_vhangup_self(void);
384 extern void disassociate_ctty(int priv);
385 extern dev_t tty_devnum(struct tty_struct *tty);
386 extern void proc_clear_tty(struct task_struct *p);
387 extern struct tty_struct *get_current_tty(void);
388 /* tty_io.c */
389 extern int __init tty_init(void);
390 extern const char *tty_name(const struct tty_struct *tty);
391 extern struct tty_struct *tty_kopen_exclusive(dev_t device);
392 extern struct tty_struct *tty_kopen_shared(dev_t device);
393 extern void tty_kclose(struct tty_struct *tty);
394 extern int tty_dev_name_to_number(const char *name, dev_t *number);
395 #else
396 static inline void tty_kref_put(struct tty_struct *tty)
397 { }
398 static inline struct pid *tty_get_pgrp(struct tty_struct *tty)
399 { return NULL; }
400 static inline void tty_vhangup_self(void)
401 { }
402 static inline void disassociate_ctty(int priv)
403 { }
404 static inline dev_t tty_devnum(struct tty_struct *tty)
405 { return 0; }
406 static inline void proc_clear_tty(struct task_struct *p)
407 { }
408 static inline struct tty_struct *get_current_tty(void)
409 { return NULL; }
410 /* tty_io.c */
411 static inline int __init tty_init(void)
412 { return 0; }
413 static inline const char *tty_name(const struct tty_struct *tty)
414 { return "(none)"; }
415 static inline struct tty_struct *tty_kopen_exclusive(dev_t device)
416 { return ERR_PTR(-ENODEV); }
417 static inline void tty_kclose(struct tty_struct *tty)
418 { }
419 static inline int tty_dev_name_to_number(const char *name, dev_t *number)
420 { return -ENOTSUPP; }
421 #endif
422 
423 extern struct ktermios tty_std_termios;
424 
425 extern int vcs_init(void);
426 
427 extern struct class *tty_class;
428 
429 /**
430  *	tty_kref_get		-	get a tty reference
431  *	@tty: tty device
432  *
433  *	Return a new reference to a tty object. The caller must hold
434  *	sufficient locks/counts to ensure that their existing reference cannot
435  *	go away
436  */
437 
438 static inline struct tty_struct *tty_kref_get(struct tty_struct *tty)
439 {
440 	if (tty)
441 		kref_get(&tty->kref);
442 	return tty;
443 }
444 
445 extern const char *tty_driver_name(const struct tty_struct *tty);
446 extern void tty_wait_until_sent(struct tty_struct *tty, long timeout);
447 extern void stop_tty(struct tty_struct *tty);
448 extern void start_tty(struct tty_struct *tty);
449 extern int tty_register_driver(struct tty_driver *driver);
450 extern void tty_unregister_driver(struct tty_driver *driver);
451 extern struct device *tty_register_device(struct tty_driver *driver,
452 					  unsigned index, struct device *dev);
453 extern struct device *tty_register_device_attr(struct tty_driver *driver,
454 				unsigned index, struct device *device,
455 				void *drvdata,
456 				const struct attribute_group **attr_grp);
457 extern void tty_unregister_device(struct tty_driver *driver, unsigned index);
458 extern void tty_write_message(struct tty_struct *tty, char *msg);
459 extern int tty_send_xchar(struct tty_struct *tty, char ch);
460 extern int tty_put_char(struct tty_struct *tty, unsigned char c);
461 extern unsigned int tty_chars_in_buffer(struct tty_struct *tty);
462 extern unsigned int tty_write_room(struct tty_struct *tty);
463 extern void tty_driver_flush_buffer(struct tty_struct *tty);
464 extern void tty_unthrottle(struct tty_struct *tty);
465 extern int tty_throttle_safe(struct tty_struct *tty);
466 extern int tty_unthrottle_safe(struct tty_struct *tty);
467 extern int tty_do_resize(struct tty_struct *tty, struct winsize *ws);
468 extern int tty_get_icount(struct tty_struct *tty,
469 			  struct serial_icounter_struct *icount);
470 extern int is_current_pgrp_orphaned(void);
471 extern void tty_hangup(struct tty_struct *tty);
472 extern void tty_vhangup(struct tty_struct *tty);
473 extern int tty_hung_up_p(struct file *filp);
474 extern void do_SAK(struct tty_struct *tty);
475 extern void __do_SAK(struct tty_struct *tty);
476 extern void no_tty(void);
477 extern speed_t tty_termios_baud_rate(struct ktermios *termios);
478 extern void tty_termios_encode_baud_rate(struct ktermios *termios,
479 						speed_t ibaud, speed_t obaud);
480 extern void tty_encode_baud_rate(struct tty_struct *tty,
481 						speed_t ibaud, speed_t obaud);
482 
483 /**
484  *	tty_get_baud_rate	-	get tty bit rates
485  *	@tty: tty to query
486  *
487  *	Returns the baud rate as an integer for this terminal. The
488  *	termios lock must be held by the caller and the terminal bit
489  *	flags may be updated.
490  *
491  *	Locking: none
492  */
493 static inline speed_t tty_get_baud_rate(struct tty_struct *tty)
494 {
495 	return tty_termios_baud_rate(&tty->termios);
496 }
497 
498 unsigned char tty_get_char_size(unsigned int cflag);
499 unsigned char tty_get_frame_size(unsigned int cflag);
500 
501 extern void tty_termios_copy_hw(struct ktermios *new, struct ktermios *old);
502 extern int tty_termios_hw_change(const struct ktermios *a, const struct ktermios *b);
503 extern int tty_set_termios(struct tty_struct *tty, struct ktermios *kt);
504 
505 extern struct tty_ldisc *tty_ldisc_ref(struct tty_struct *);
506 extern void tty_ldisc_deref(struct tty_ldisc *);
507 extern struct tty_ldisc *tty_ldisc_ref_wait(struct tty_struct *);
508 extern const struct seq_operations tty_ldiscs_seq_ops;
509 
510 extern void tty_wakeup(struct tty_struct *tty);
511 extern void tty_ldisc_flush(struct tty_struct *tty);
512 
513 extern int tty_mode_ioctl(struct tty_struct *tty, struct file *file,
514 			unsigned int cmd, unsigned long arg);
515 extern int tty_perform_flush(struct tty_struct *tty, unsigned long arg);
516 extern struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx);
517 extern void tty_release_struct(struct tty_struct *tty, int idx);
518 extern void tty_init_termios(struct tty_struct *tty);
519 extern void tty_save_termios(struct tty_struct *tty);
520 extern int tty_standard_install(struct tty_driver *driver,
521 		struct tty_struct *tty);
522 
523 extern struct mutex tty_mutex;
524 
525 extern void tty_port_init(struct tty_port *port);
526 extern void tty_port_link_device(struct tty_port *port,
527 		struct tty_driver *driver, unsigned index);
528 extern struct device *tty_port_register_device(struct tty_port *port,
529 		struct tty_driver *driver, unsigned index,
530 		struct device *device);
531 extern struct device *tty_port_register_device_attr(struct tty_port *port,
532 		struct tty_driver *driver, unsigned index,
533 		struct device *device, void *drvdata,
534 		const struct attribute_group **attr_grp);
535 extern struct device *tty_port_register_device_serdev(struct tty_port *port,
536 		struct tty_driver *driver, unsigned index,
537 		struct device *device);
538 extern struct device *tty_port_register_device_attr_serdev(struct tty_port *port,
539 		struct tty_driver *driver, unsigned index,
540 		struct device *device, void *drvdata,
541 		const struct attribute_group **attr_grp);
542 extern void tty_port_unregister_device(struct tty_port *port,
543 		struct tty_driver *driver, unsigned index);
544 extern int tty_port_alloc_xmit_buf(struct tty_port *port);
545 extern void tty_port_free_xmit_buf(struct tty_port *port);
546 extern void tty_port_destroy(struct tty_port *port);
547 extern void tty_port_put(struct tty_port *port);
548 
549 static inline struct tty_port *tty_port_get(struct tty_port *port)
550 {
551 	if (port && kref_get_unless_zero(&port->kref))
552 		return port;
553 	return NULL;
554 }
555 
556 /* If the cts flow control is enabled, return true. */
557 static inline bool tty_port_cts_enabled(const struct tty_port *port)
558 {
559 	return test_bit(TTY_PORT_CTS_FLOW, &port->iflags);
560 }
561 
562 static inline void tty_port_set_cts_flow(struct tty_port *port, bool val)
563 {
564 	assign_bit(TTY_PORT_CTS_FLOW, &port->iflags, val);
565 }
566 
567 static inline bool tty_port_active(const struct tty_port *port)
568 {
569 	return test_bit(TTY_PORT_ACTIVE, &port->iflags);
570 }
571 
572 static inline void tty_port_set_active(struct tty_port *port, bool val)
573 {
574 	assign_bit(TTY_PORT_ACTIVE, &port->iflags, val);
575 }
576 
577 static inline bool tty_port_check_carrier(const struct tty_port *port)
578 {
579 	return test_bit(TTY_PORT_CHECK_CD, &port->iflags);
580 }
581 
582 static inline void tty_port_set_check_carrier(struct tty_port *port, bool val)
583 {
584 	assign_bit(TTY_PORT_CHECK_CD, &port->iflags, val);
585 }
586 
587 static inline bool tty_port_suspended(const struct tty_port *port)
588 {
589 	return test_bit(TTY_PORT_SUSPENDED, &port->iflags);
590 }
591 
592 static inline void tty_port_set_suspended(struct tty_port *port, bool val)
593 {
594 	assign_bit(TTY_PORT_SUSPENDED, &port->iflags, val);
595 }
596 
597 static inline bool tty_port_initialized(const struct tty_port *port)
598 {
599 	return test_bit(TTY_PORT_INITIALIZED, &port->iflags);
600 }
601 
602 static inline void tty_port_set_initialized(struct tty_port *port, bool val)
603 {
604 	assign_bit(TTY_PORT_INITIALIZED, &port->iflags, val);
605 }
606 
607 static inline bool tty_port_kopened(const struct tty_port *port)
608 {
609 	return test_bit(TTY_PORT_KOPENED, &port->iflags);
610 }
611 
612 static inline void tty_port_set_kopened(struct tty_port *port, bool val)
613 {
614 	assign_bit(TTY_PORT_KOPENED, &port->iflags, val);
615 }
616 
617 extern struct tty_struct *tty_port_tty_get(struct tty_port *port);
618 extern void tty_port_tty_set(struct tty_port *port, struct tty_struct *tty);
619 extern int tty_port_carrier_raised(struct tty_port *port);
620 extern void tty_port_raise_dtr_rts(struct tty_port *port);
621 extern void tty_port_lower_dtr_rts(struct tty_port *port);
622 extern void tty_port_hangup(struct tty_port *port);
623 extern void tty_port_tty_hangup(struct tty_port *port, bool check_clocal);
624 extern void tty_port_tty_wakeup(struct tty_port *port);
625 extern int tty_port_block_til_ready(struct tty_port *port,
626 				struct tty_struct *tty, struct file *filp);
627 extern int tty_port_close_start(struct tty_port *port,
628 				struct tty_struct *tty, struct file *filp);
629 extern void tty_port_close_end(struct tty_port *port, struct tty_struct *tty);
630 extern void tty_port_close(struct tty_port *port,
631 				struct tty_struct *tty, struct file *filp);
632 extern int tty_port_install(struct tty_port *port, struct tty_driver *driver,
633 				struct tty_struct *tty);
634 extern int tty_port_open(struct tty_port *port,
635 				struct tty_struct *tty, struct file *filp);
636 static inline int tty_port_users(struct tty_port *port)
637 {
638 	return port->count + port->blocked_open;
639 }
640 
641 extern int tty_register_ldisc(struct tty_ldisc_ops *new_ldisc);
642 extern void tty_unregister_ldisc(struct tty_ldisc_ops *ldisc);
643 extern int tty_set_ldisc(struct tty_struct *tty, int disc);
644 extern int tty_ldisc_receive_buf(struct tty_ldisc *ld, const unsigned char *p,
645 				 const char *f, int count);
646 
647 /* n_tty.c */
648 extern void n_tty_inherit_ops(struct tty_ldisc_ops *ops);
649 #ifdef CONFIG_TTY
650 extern void __init n_tty_init(void);
651 #else
652 static inline void n_tty_init(void) { }
653 #endif
654 
655 /* tty_audit.c */
656 #ifdef CONFIG_AUDIT
657 extern void tty_audit_exit(void);
658 extern void tty_audit_fork(struct signal_struct *sig);
659 extern int tty_audit_push(void);
660 #else
661 static inline void tty_audit_exit(void)
662 {
663 }
664 static inline void tty_audit_fork(struct signal_struct *sig)
665 {
666 }
667 static inline int tty_audit_push(void)
668 {
669 	return 0;
670 }
671 #endif
672 
673 /* tty_ioctl.c */
674 extern int n_tty_ioctl_helper(struct tty_struct *tty, struct file *file,
675 		       unsigned int cmd, unsigned long arg);
676 
677 /* vt.c */
678 
679 extern int vt_ioctl(struct tty_struct *tty,
680 		    unsigned int cmd, unsigned long arg);
681 
682 extern long vt_compat_ioctl(struct tty_struct *tty,
683 		     unsigned int cmd, unsigned long arg);
684 
685 /* tty_mutex.c */
686 /* functions for preparation of BKL removal */
687 extern void tty_lock(struct tty_struct *tty);
688 extern int  tty_lock_interruptible(struct tty_struct *tty);
689 extern void tty_unlock(struct tty_struct *tty);
690 extern void tty_lock_slave(struct tty_struct *tty);
691 extern void tty_unlock_slave(struct tty_struct *tty);
692 extern void tty_set_lock_subclass(struct tty_struct *tty);
693 
694 #ifdef CONFIG_PROC_FS
695 extern void proc_tty_register_driver(struct tty_driver *);
696 extern void proc_tty_unregister_driver(struct tty_driver *);
697 #else
698 static inline void proc_tty_register_driver(struct tty_driver *d) {}
699 static inline void proc_tty_unregister_driver(struct tty_driver *d) {}
700 #endif
701 
702 #endif
703