xref: /linux-6.15/include/linux/tty.h (revision 4f6d9bfc)
1 #ifndef _LINUX_TTY_H
2 #define _LINUX_TTY_H
3 
4 #include <linux/fs.h>
5 #include <linux/major.h>
6 #include <linux/termios.h>
7 #include <linux/workqueue.h>
8 #include <linux/tty_driver.h>
9 #include <linux/tty_ldisc.h>
10 #include <linux/mutex.h>
11 #include <linux/tty_flags.h>
12 #include <uapi/linux/tty.h>
13 #include <linux/rwsem.h>
14 #include <linux/llist.h>
15 
16 
17 /*
18  * Lock subclasses for tty locks
19  *
20  * TTY_LOCK_NORMAL is for normal ttys and master ptys.
21  * TTY_LOCK_SLAVE is for slave ptys only.
22  *
23  * Lock subclasses are necessary for handling nested locking with pty pairs.
24  * tty locks which use nested locking:
25  *
26  * legacy_mutex - Nested tty locks are necessary for releasing pty pairs.
27  *		  The stable lock order is master pty first, then slave pty.
28  * termios_rwsem - The stable lock order is tty_buffer lock->termios_rwsem.
29  *		   Subclassing this lock enables the slave pty to hold its
30  *		   termios_rwsem when claiming the master tty_buffer lock.
31  * tty_buffer lock - slave ptys can claim nested buffer lock when handling
32  *		     signal chars. The stable lock order is slave pty, then
33  *		     master.
34  */
35 
36 enum {
37 	TTY_LOCK_NORMAL = 0,
38 	TTY_LOCK_SLAVE,
39 };
40 
41 /*
42  * (Note: the *_driver.minor_start values 1, 64, 128, 192 are
43  * hardcoded at present.)
44  */
45 #define NR_UNIX98_PTY_DEFAULT	4096      /* Default maximum for Unix98 ptys */
46 #define NR_UNIX98_PTY_RESERVE	1024	  /* Default reserve for main devpts */
47 #define NR_UNIX98_PTY_MAX	(1 << MINORBITS) /* Absolute limit */
48 
49 /*
50  * This character is the same as _POSIX_VDISABLE: it cannot be used as
51  * a c_cc[] character, but indicates that a particular special character
52  * isn't in use (eg VINTR has no character etc)
53  */
54 #define __DISABLED_CHAR '\0'
55 
56 struct tty_buffer {
57 	union {
58 		struct tty_buffer *next;
59 		struct llist_node free;
60 	};
61 	int used;
62 	int size;
63 	int commit;
64 	int read;
65 	int flags;
66 	/* Data points here */
67 	unsigned long data[0];
68 };
69 
70 /* Values for .flags field of tty_buffer */
71 #define TTYB_NORMAL	1	/* buffer has no flags buffer */
72 
73 static inline unsigned char *char_buf_ptr(struct tty_buffer *b, int ofs)
74 {
75 	return ((unsigned char *)b->data) + ofs;
76 }
77 
78 static inline char *flag_buf_ptr(struct tty_buffer *b, int ofs)
79 {
80 	return (char *)char_buf_ptr(b, ofs) + b->size;
81 }
82 
83 struct tty_bufhead {
84 	struct tty_buffer *head;	/* Queue head */
85 	struct work_struct work;
86 	struct mutex	   lock;
87 	atomic_t	   priority;
88 	struct tty_buffer sentinel;
89 	struct llist_head free;		/* Free queue head */
90 	atomic_t	   mem_used;    /* In-use buffers excluding free list */
91 	int		   mem_limit;
92 	struct tty_buffer *tail;	/* Active buffer */
93 };
94 /*
95  * When a break, frame error, or parity error happens, these codes are
96  * stuffed into the flags buffer.
97  */
98 #define TTY_NORMAL	0
99 #define TTY_BREAK	1
100 #define TTY_FRAME	2
101 #define TTY_PARITY	3
102 #define TTY_OVERRUN	4
103 
104 #define INTR_CHAR(tty) ((tty)->termios.c_cc[VINTR])
105 #define QUIT_CHAR(tty) ((tty)->termios.c_cc[VQUIT])
106 #define ERASE_CHAR(tty) ((tty)->termios.c_cc[VERASE])
107 #define KILL_CHAR(tty) ((tty)->termios.c_cc[VKILL])
108 #define EOF_CHAR(tty) ((tty)->termios.c_cc[VEOF])
109 #define TIME_CHAR(tty) ((tty)->termios.c_cc[VTIME])
110 #define MIN_CHAR(tty) ((tty)->termios.c_cc[VMIN])
111 #define SWTC_CHAR(tty) ((tty)->termios.c_cc[VSWTC])
112 #define START_CHAR(tty) ((tty)->termios.c_cc[VSTART])
113 #define STOP_CHAR(tty) ((tty)->termios.c_cc[VSTOP])
114 #define SUSP_CHAR(tty) ((tty)->termios.c_cc[VSUSP])
115 #define EOL_CHAR(tty) ((tty)->termios.c_cc[VEOL])
116 #define REPRINT_CHAR(tty) ((tty)->termios.c_cc[VREPRINT])
117 #define DISCARD_CHAR(tty) ((tty)->termios.c_cc[VDISCARD])
118 #define WERASE_CHAR(tty) ((tty)->termios.c_cc[VWERASE])
119 #define LNEXT_CHAR(tty)	((tty)->termios.c_cc[VLNEXT])
120 #define EOL2_CHAR(tty) ((tty)->termios.c_cc[VEOL2])
121 
122 #define _I_FLAG(tty, f)	((tty)->termios.c_iflag & (f))
123 #define _O_FLAG(tty, f)	((tty)->termios.c_oflag & (f))
124 #define _C_FLAG(tty, f)	((tty)->termios.c_cflag & (f))
125 #define _L_FLAG(tty, f)	((tty)->termios.c_lflag & (f))
126 
127 #define I_IGNBRK(tty)	_I_FLAG((tty), IGNBRK)
128 #define I_BRKINT(tty)	_I_FLAG((tty), BRKINT)
129 #define I_IGNPAR(tty)	_I_FLAG((tty), IGNPAR)
130 #define I_PARMRK(tty)	_I_FLAG((tty), PARMRK)
131 #define I_INPCK(tty)	_I_FLAG((tty), INPCK)
132 #define I_ISTRIP(tty)	_I_FLAG((tty), ISTRIP)
133 #define I_INLCR(tty)	_I_FLAG((tty), INLCR)
134 #define I_IGNCR(tty)	_I_FLAG((tty), IGNCR)
135 #define I_ICRNL(tty)	_I_FLAG((tty), ICRNL)
136 #define I_IUCLC(tty)	_I_FLAG((tty), IUCLC)
137 #define I_IXON(tty)	_I_FLAG((tty), IXON)
138 #define I_IXANY(tty)	_I_FLAG((tty), IXANY)
139 #define I_IXOFF(tty)	_I_FLAG((tty), IXOFF)
140 #define I_IMAXBEL(tty)	_I_FLAG((tty), IMAXBEL)
141 #define I_IUTF8(tty)	_I_FLAG((tty), IUTF8)
142 
143 #define O_OPOST(tty)	_O_FLAG((tty), OPOST)
144 #define O_OLCUC(tty)	_O_FLAG((tty), OLCUC)
145 #define O_ONLCR(tty)	_O_FLAG((tty), ONLCR)
146 #define O_OCRNL(tty)	_O_FLAG((tty), OCRNL)
147 #define O_ONOCR(tty)	_O_FLAG((tty), ONOCR)
148 #define O_ONLRET(tty)	_O_FLAG((tty), ONLRET)
149 #define O_OFILL(tty)	_O_FLAG((tty), OFILL)
150 #define O_OFDEL(tty)	_O_FLAG((tty), OFDEL)
151 #define O_NLDLY(tty)	_O_FLAG((tty), NLDLY)
152 #define O_CRDLY(tty)	_O_FLAG((tty), CRDLY)
153 #define O_TABDLY(tty)	_O_FLAG((tty), TABDLY)
154 #define O_BSDLY(tty)	_O_FLAG((tty), BSDLY)
155 #define O_VTDLY(tty)	_O_FLAG((tty), VTDLY)
156 #define O_FFDLY(tty)	_O_FLAG((tty), FFDLY)
157 
158 #define C_BAUD(tty)	_C_FLAG((tty), CBAUD)
159 #define C_CSIZE(tty)	_C_FLAG((tty), CSIZE)
160 #define C_CSTOPB(tty)	_C_FLAG((tty), CSTOPB)
161 #define C_CREAD(tty)	_C_FLAG((tty), CREAD)
162 #define C_PARENB(tty)	_C_FLAG((tty), PARENB)
163 #define C_PARODD(tty)	_C_FLAG((tty), PARODD)
164 #define C_HUPCL(tty)	_C_FLAG((tty), HUPCL)
165 #define C_CLOCAL(tty)	_C_FLAG((tty), CLOCAL)
166 #define C_CIBAUD(tty)	_C_FLAG((tty), CIBAUD)
167 #define C_CRTSCTS(tty)	_C_FLAG((tty), CRTSCTS)
168 #define C_CMSPAR(tty)	_C_FLAG((tty), CMSPAR)
169 
170 #define L_ISIG(tty)	_L_FLAG((tty), ISIG)
171 #define L_ICANON(tty)	_L_FLAG((tty), ICANON)
172 #define L_XCASE(tty)	_L_FLAG((tty), XCASE)
173 #define L_ECHO(tty)	_L_FLAG((tty), ECHO)
174 #define L_ECHOE(tty)	_L_FLAG((tty), ECHOE)
175 #define L_ECHOK(tty)	_L_FLAG((tty), ECHOK)
176 #define L_ECHONL(tty)	_L_FLAG((tty), ECHONL)
177 #define L_NOFLSH(tty)	_L_FLAG((tty), NOFLSH)
178 #define L_TOSTOP(tty)	_L_FLAG((tty), TOSTOP)
179 #define L_ECHOCTL(tty)	_L_FLAG((tty), ECHOCTL)
180 #define L_ECHOPRT(tty)	_L_FLAG((tty), ECHOPRT)
181 #define L_ECHOKE(tty)	_L_FLAG((tty), ECHOKE)
182 #define L_FLUSHO(tty)	_L_FLAG((tty), FLUSHO)
183 #define L_PENDIN(tty)	_L_FLAG((tty), PENDIN)
184 #define L_IEXTEN(tty)	_L_FLAG((tty), IEXTEN)
185 #define L_EXTPROC(tty)	_L_FLAG((tty), EXTPROC)
186 
187 struct device;
188 struct signal_struct;
189 
190 /*
191  * Port level information. Each device keeps its own port level information
192  * so provide a common structure for those ports wanting to use common support
193  * routines.
194  *
195  * The tty port has a different lifetime to the tty so must be kept apart.
196  * In addition be careful as tty -> port mappings are valid for the life
197  * of the tty object but in many cases port -> tty mappings are valid only
198  * until a hangup so don't use the wrong path.
199  */
200 
201 struct tty_port;
202 
203 struct tty_port_operations {
204 	/* Return 1 if the carrier is raised */
205 	int (*carrier_raised)(struct tty_port *port);
206 	/* Control the DTR line */
207 	void (*dtr_rts)(struct tty_port *port, int raise);
208 	/* Called when the last close completes or a hangup finishes
209 	   IFF the port was initialized. Do not use to free resources. Called
210 	   under the port mutex to serialize against activate/shutdowns */
211 	void (*shutdown)(struct tty_port *port);
212 	/* Called under the port mutex from tty_port_open, serialized using
213 	   the port mutex */
214         /* FIXME: long term getting the tty argument *out* of this would be
215            good for consoles */
216 	int (*activate)(struct tty_port *port, struct tty_struct *tty);
217 	/* Called on the final put of a port */
218 	void (*destruct)(struct tty_port *port);
219 };
220 
221 struct tty_port_client_operations {
222 	int (*receive_buf)(struct tty_port *port, const unsigned char *, const unsigned char *, size_t);
223 	void (*write_wakeup)(struct tty_port *port);
224 };
225 
226 struct tty_port {
227 	struct tty_bufhead	buf;		/* Locked internally */
228 	struct tty_struct	*tty;		/* Back pointer */
229 	struct tty_struct	*itty;		/* internal back ptr */
230 	const struct tty_port_operations *ops;	/* Port operations */
231 	const struct tty_port_client_operations *client_ops; /* Port client operations */
232 	spinlock_t		lock;		/* Lock protecting tty field */
233 	int			blocked_open;	/* Waiting to open */
234 	int			count;		/* Usage count */
235 	wait_queue_head_t	open_wait;	/* Open waiters */
236 	wait_queue_head_t	delta_msr_wait;	/* Modem status change */
237 	unsigned long		flags;		/* User TTY flags ASYNC_ */
238 	unsigned long		iflags;		/* Internal flags TTY_PORT_ */
239 	unsigned char		console:1,	/* port is a console */
240 				low_latency:1;	/* optional: tune for latency */
241 	struct mutex		mutex;		/* Locking */
242 	struct mutex		buf_mutex;	/* Buffer alloc lock */
243 	unsigned char		*xmit_buf;	/* Optional buffer */
244 	unsigned int		close_delay;	/* Close port delay */
245 	unsigned int		closing_wait;	/* Delay for output */
246 	int			drain_delay;	/* Set to zero if no pure time
247 						   based drain is needed else
248 						   set to size of fifo */
249 	struct kref		kref;		/* Ref counter */
250 	void 			*client_data;
251 };
252 
253 /* tty_port::iflags bits -- use atomic bit ops */
254 #define TTY_PORT_INITIALIZED	0	/* device is initialized */
255 #define TTY_PORT_SUSPENDED	1	/* device is suspended */
256 #define TTY_PORT_ACTIVE		2	/* device is open */
257 
258 /*
259  * uart drivers: use the uart_port::status field and the UPSTAT_* defines
260  * for s/w-based flow control steering and carrier detection status
261  */
262 #define TTY_PORT_CTS_FLOW	3	/* h/w flow control enabled */
263 #define TTY_PORT_CHECK_CD	4	/* carrier detect enabled */
264 
265 /*
266  * Where all of the state associated with a tty is kept while the tty
267  * is open.  Since the termios state should be kept even if the tty
268  * has been closed --- for things like the baud rate, etc --- it is
269  * not stored here, but rather a pointer to the real state is stored
270  * here.  Possible the winsize structure should have the same
271  * treatment, but (1) the default 80x24 is usually right and (2) it's
272  * most often used by a windowing system, which will set the correct
273  * size each time the window is created or resized anyway.
274  * 						- TYT, 9/14/92
275  */
276 
277 struct tty_operations;
278 
279 struct tty_struct {
280 	int	magic;
281 	struct kref kref;
282 	struct device *dev;
283 	struct tty_driver *driver;
284 	const struct tty_operations *ops;
285 	int index;
286 
287 	/* Protects ldisc changes: Lock tty not pty */
288 	struct ld_semaphore ldisc_sem;
289 	struct tty_ldisc *ldisc;
290 
291 	struct mutex atomic_write_lock;
292 	struct mutex legacy_mutex;
293 	struct mutex throttle_mutex;
294 	struct rw_semaphore termios_rwsem;
295 	struct mutex winsize_mutex;
296 	spinlock_t ctrl_lock;
297 	spinlock_t flow_lock;
298 	/* Termios values are protected by the termios rwsem */
299 	struct ktermios termios, termios_locked;
300 	struct termiox *termiox;	/* May be NULL for unsupported */
301 	char name[64];
302 	struct pid *pgrp;		/* Protected by ctrl lock */
303 	struct pid *session;
304 	unsigned long flags;
305 	int count;
306 	struct winsize winsize;		/* winsize_mutex */
307 	unsigned long stopped:1,	/* flow_lock */
308 		      flow_stopped:1,
309 		      unused:BITS_PER_LONG - 2;
310 	int hw_stopped;
311 	unsigned long ctrl_status:8,	/* ctrl_lock */
312 		      packet:1,
313 		      unused_ctrl:BITS_PER_LONG - 9;
314 	unsigned int receive_room;	/* Bytes free for queue */
315 	int flow_change;
316 
317 	struct tty_struct *link;
318 	struct fasync_struct *fasync;
319 	int alt_speed;		/* For magic substitution of 38400 bps */
320 	wait_queue_head_t write_wait;
321 	wait_queue_head_t read_wait;
322 	struct work_struct hangup_work;
323 	void *disc_data;
324 	void *driver_data;
325 	spinlock_t files_lock;		/* protects tty_files list */
326 	struct list_head tty_files;
327 
328 #define N_TTY_BUF_SIZE 4096
329 
330 	int closing;
331 	unsigned char *write_buf;
332 	int write_cnt;
333 	/* If the tty has a pending do_SAK, queue it here - akpm */
334 	struct work_struct SAK_work;
335 	struct tty_port *port;
336 };
337 
338 /* Each of a tty's open files has private_data pointing to tty_file_private */
339 struct tty_file_private {
340 	struct tty_struct *tty;
341 	struct file *file;
342 	struct list_head list;
343 };
344 
345 /* tty magic number */
346 #define TTY_MAGIC		0x5401
347 
348 /*
349  * These bits are used in the flags field of the tty structure.
350  *
351  * So that interrupts won't be able to mess up the queues,
352  * copy_to_cooked must be atomic with respect to itself, as must
353  * tty->write.  Thus, you must use the inline functions set_bit() and
354  * clear_bit() to make things atomic.
355  */
356 #define TTY_THROTTLED 		0	/* Call unthrottle() at threshold min */
357 #define TTY_IO_ERROR 		1	/* Cause an I/O error (may be no ldisc too) */
358 #define TTY_OTHER_CLOSED 	2	/* Other side (if any) has closed */
359 #define TTY_EXCLUSIVE 		3	/* Exclusive open mode */
360 #define TTY_DO_WRITE_WAKEUP 	5	/* Call write_wakeup after queuing new */
361 #define TTY_LDISC_OPEN	 	11	/* Line discipline is open */
362 #define TTY_PTY_LOCK 		16	/* pty private */
363 #define TTY_NO_WRITE_SPLIT 	17	/* Preserve write boundaries to driver */
364 #define TTY_HUPPED 		18	/* Post driver->hangup() */
365 #define TTY_LDISC_HALTED	22	/* Line discipline is halted */
366 
367 /* Values for tty->flow_change */
368 #define TTY_THROTTLE_SAFE 1
369 #define TTY_UNTHROTTLE_SAFE 2
370 
371 static inline void __tty_set_flow_change(struct tty_struct *tty, int val)
372 {
373 	tty->flow_change = val;
374 }
375 
376 static inline void tty_set_flow_change(struct tty_struct *tty, int val)
377 {
378 	tty->flow_change = val;
379 	smp_mb();
380 }
381 
382 static inline bool tty_io_error(struct tty_struct *tty)
383 {
384 	return test_bit(TTY_IO_ERROR, &tty->flags);
385 }
386 
387 static inline bool tty_throttled(struct tty_struct *tty)
388 {
389 	return test_bit(TTY_THROTTLED, &tty->flags);
390 }
391 
392 #ifdef CONFIG_TTY
393 extern void console_init(void);
394 extern void tty_kref_put(struct tty_struct *tty);
395 extern struct pid *tty_get_pgrp(struct tty_struct *tty);
396 extern void tty_vhangup_self(void);
397 extern void disassociate_ctty(int priv);
398 extern dev_t tty_devnum(struct tty_struct *tty);
399 extern void proc_clear_tty(struct task_struct *p);
400 extern struct tty_struct *get_current_tty(void);
401 /* tty_io.c */
402 extern int __init tty_init(void);
403 extern const char *tty_name(const struct tty_struct *tty);
404 #else
405 static inline void console_init(void)
406 { }
407 static inline void tty_kref_put(struct tty_struct *tty)
408 { }
409 static inline struct pid *tty_get_pgrp(struct tty_struct *tty)
410 { return NULL; }
411 static inline void tty_vhangup_self(void)
412 { }
413 static inline void disassociate_ctty(int priv)
414 { }
415 static inline dev_t tty_devnum(struct tty_struct *tty)
416 { return 0; }
417 static inline void proc_clear_tty(struct task_struct *p)
418 { }
419 static inline struct tty_struct *get_current_tty(void)
420 { return NULL; }
421 /* tty_io.c */
422 static inline int __init tty_init(void)
423 { return 0; }
424 static inline const char *tty_name(const struct tty_struct *tty)
425 { return "(none)"; }
426 #endif
427 
428 extern struct ktermios tty_std_termios;
429 
430 extern int vcs_init(void);
431 
432 extern struct class *tty_class;
433 
434 /**
435  *	tty_kref_get		-	get a tty reference
436  *	@tty: tty device
437  *
438  *	Return a new reference to a tty object. The caller must hold
439  *	sufficient locks/counts to ensure that their existing reference cannot
440  *	go away
441  */
442 
443 static inline struct tty_struct *tty_kref_get(struct tty_struct *tty)
444 {
445 	if (tty)
446 		kref_get(&tty->kref);
447 	return tty;
448 }
449 
450 extern const char *tty_driver_name(const struct tty_struct *tty);
451 extern void tty_wait_until_sent(struct tty_struct *tty, long timeout);
452 extern int __tty_check_change(struct tty_struct *tty, int sig);
453 extern int tty_check_change(struct tty_struct *tty);
454 extern void __stop_tty(struct tty_struct *tty);
455 extern void stop_tty(struct tty_struct *tty);
456 extern void __start_tty(struct tty_struct *tty);
457 extern void start_tty(struct tty_struct *tty);
458 extern int tty_register_driver(struct tty_driver *driver);
459 extern int tty_unregister_driver(struct tty_driver *driver);
460 extern struct device *tty_register_device(struct tty_driver *driver,
461 					  unsigned index, struct device *dev);
462 extern struct device *tty_register_device_attr(struct tty_driver *driver,
463 				unsigned index, struct device *device,
464 				void *drvdata,
465 				const struct attribute_group **attr_grp);
466 extern void tty_unregister_device(struct tty_driver *driver, unsigned index);
467 extern void tty_write_message(struct tty_struct *tty, char *msg);
468 extern int tty_send_xchar(struct tty_struct *tty, char ch);
469 extern int tty_put_char(struct tty_struct *tty, unsigned char c);
470 extern int tty_chars_in_buffer(struct tty_struct *tty);
471 extern int tty_write_room(struct tty_struct *tty);
472 extern void tty_driver_flush_buffer(struct tty_struct *tty);
473 extern void tty_throttle(struct tty_struct *tty);
474 extern void tty_unthrottle(struct tty_struct *tty);
475 extern int tty_throttle_safe(struct tty_struct *tty);
476 extern int tty_unthrottle_safe(struct tty_struct *tty);
477 extern int tty_do_resize(struct tty_struct *tty, struct winsize *ws);
478 extern int is_current_pgrp_orphaned(void);
479 extern void tty_hangup(struct tty_struct *tty);
480 extern void tty_vhangup(struct tty_struct *tty);
481 extern int tty_hung_up_p(struct file *filp);
482 extern void do_SAK(struct tty_struct *tty);
483 extern void __do_SAK(struct tty_struct *tty);
484 extern void no_tty(void);
485 extern void tty_buffer_free_all(struct tty_port *port);
486 extern void tty_buffer_flush(struct tty_struct *tty, struct tty_ldisc *ld);
487 extern void tty_buffer_init(struct tty_port *port);
488 extern void tty_buffer_set_lock_subclass(struct tty_port *port);
489 extern bool tty_buffer_restart_work(struct tty_port *port);
490 extern bool tty_buffer_cancel_work(struct tty_port *port);
491 extern void tty_buffer_flush_work(struct tty_port *port);
492 extern speed_t tty_termios_baud_rate(struct ktermios *termios);
493 extern speed_t tty_termios_input_baud_rate(struct ktermios *termios);
494 extern void tty_termios_encode_baud_rate(struct ktermios *termios,
495 						speed_t ibaud, speed_t obaud);
496 extern void tty_encode_baud_rate(struct tty_struct *tty,
497 						speed_t ibaud, speed_t obaud);
498 
499 /**
500  *	tty_get_baud_rate	-	get tty bit rates
501  *	@tty: tty to query
502  *
503  *	Returns the baud rate as an integer for this terminal. The
504  *	termios lock must be held by the caller and the terminal bit
505  *	flags may be updated.
506  *
507  *	Locking: none
508  */
509 static inline speed_t tty_get_baud_rate(struct tty_struct *tty)
510 {
511 	return tty_termios_baud_rate(&tty->termios);
512 }
513 
514 extern void tty_termios_copy_hw(struct ktermios *new, struct ktermios *old);
515 extern int tty_termios_hw_change(struct ktermios *a, struct ktermios *b);
516 extern int tty_set_termios(struct tty_struct *tty, struct ktermios *kt);
517 
518 extern struct tty_ldisc *tty_ldisc_ref(struct tty_struct *);
519 extern void tty_ldisc_deref(struct tty_ldisc *);
520 extern struct tty_ldisc *tty_ldisc_ref_wait(struct tty_struct *);
521 extern void tty_ldisc_hangup(struct tty_struct *tty, bool reset);
522 extern int tty_ldisc_reinit(struct tty_struct *tty, int disc);
523 extern const struct file_operations tty_ldiscs_proc_fops;
524 
525 extern void tty_wakeup(struct tty_struct *tty);
526 extern void tty_ldisc_flush(struct tty_struct *tty);
527 
528 extern long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
529 extern int tty_mode_ioctl(struct tty_struct *tty, struct file *file,
530 			unsigned int cmd, unsigned long arg);
531 extern int tty_perform_flush(struct tty_struct *tty, unsigned long arg);
532 extern void tty_default_fops(struct file_operations *fops);
533 extern struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx);
534 extern int tty_alloc_file(struct file *file);
535 extern void tty_add_file(struct tty_struct *tty, struct file *file);
536 extern void tty_free_file(struct file *file);
537 extern struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx);
538 extern void tty_release_struct(struct tty_struct *tty, int idx);
539 extern int tty_release(struct inode *inode, struct file *filp);
540 extern void tty_init_termios(struct tty_struct *tty);
541 extern int tty_standard_install(struct tty_driver *driver,
542 		struct tty_struct *tty);
543 
544 extern struct mutex tty_mutex;
545 
546 #define tty_is_writelocked(tty)  (mutex_is_locked(&tty->atomic_write_lock))
547 
548 extern void tty_port_init(struct tty_port *port);
549 extern void tty_port_link_device(struct tty_port *port,
550 		struct tty_driver *driver, unsigned index);
551 extern struct device *tty_port_register_device(struct tty_port *port,
552 		struct tty_driver *driver, unsigned index,
553 		struct device *device);
554 extern struct device *tty_port_register_device_attr(struct tty_port *port,
555 		struct tty_driver *driver, unsigned index,
556 		struct device *device, void *drvdata,
557 		const struct attribute_group **attr_grp);
558 extern int tty_port_alloc_xmit_buf(struct tty_port *port);
559 extern void tty_port_free_xmit_buf(struct tty_port *port);
560 extern void tty_port_destroy(struct tty_port *port);
561 extern void tty_port_put(struct tty_port *port);
562 
563 static inline struct tty_port *tty_port_get(struct tty_port *port)
564 {
565 	if (port && kref_get_unless_zero(&port->kref))
566 		return port;
567 	return NULL;
568 }
569 
570 /* If the cts flow control is enabled, return true. */
571 static inline bool tty_port_cts_enabled(struct tty_port *port)
572 {
573 	return test_bit(TTY_PORT_CTS_FLOW, &port->iflags);
574 }
575 
576 static inline void tty_port_set_cts_flow(struct tty_port *port, bool val)
577 {
578 	if (val)
579 		set_bit(TTY_PORT_CTS_FLOW, &port->iflags);
580 	else
581 		clear_bit(TTY_PORT_CTS_FLOW, &port->iflags);
582 }
583 
584 static inline bool tty_port_active(struct tty_port *port)
585 {
586 	return test_bit(TTY_PORT_ACTIVE, &port->iflags);
587 }
588 
589 static inline void tty_port_set_active(struct tty_port *port, bool val)
590 {
591 	if (val)
592 		set_bit(TTY_PORT_ACTIVE, &port->iflags);
593 	else
594 		clear_bit(TTY_PORT_ACTIVE, &port->iflags);
595 }
596 
597 static inline bool tty_port_check_carrier(struct tty_port *port)
598 {
599 	return test_bit(TTY_PORT_CHECK_CD, &port->iflags);
600 }
601 
602 static inline void tty_port_set_check_carrier(struct tty_port *port, bool val)
603 {
604 	if (val)
605 		set_bit(TTY_PORT_CHECK_CD, &port->iflags);
606 	else
607 		clear_bit(TTY_PORT_CHECK_CD, &port->iflags);
608 }
609 
610 static inline bool tty_port_suspended(struct tty_port *port)
611 {
612 	return test_bit(TTY_PORT_SUSPENDED, &port->iflags);
613 }
614 
615 static inline void tty_port_set_suspended(struct tty_port *port, bool val)
616 {
617 	if (val)
618 		set_bit(TTY_PORT_SUSPENDED, &port->iflags);
619 	else
620 		clear_bit(TTY_PORT_SUSPENDED, &port->iflags);
621 }
622 
623 static inline bool tty_port_initialized(struct tty_port *port)
624 {
625 	return test_bit(TTY_PORT_INITIALIZED, &port->iflags);
626 }
627 
628 static inline void tty_port_set_initialized(struct tty_port *port, bool val)
629 {
630 	if (val)
631 		set_bit(TTY_PORT_INITIALIZED, &port->iflags);
632 	else
633 		clear_bit(TTY_PORT_INITIALIZED, &port->iflags);
634 }
635 
636 extern struct tty_struct *tty_port_tty_get(struct tty_port *port);
637 extern void tty_port_tty_set(struct tty_port *port, struct tty_struct *tty);
638 extern int tty_port_carrier_raised(struct tty_port *port);
639 extern void tty_port_raise_dtr_rts(struct tty_port *port);
640 extern void tty_port_lower_dtr_rts(struct tty_port *port);
641 extern void tty_port_hangup(struct tty_port *port);
642 extern void tty_port_tty_hangup(struct tty_port *port, bool check_clocal);
643 extern void tty_port_tty_wakeup(struct tty_port *port);
644 extern int tty_port_block_til_ready(struct tty_port *port,
645 				struct tty_struct *tty, struct file *filp);
646 extern int tty_port_close_start(struct tty_port *port,
647 				struct tty_struct *tty, struct file *filp);
648 extern void tty_port_close_end(struct tty_port *port, struct tty_struct *tty);
649 extern void tty_port_close(struct tty_port *port,
650 				struct tty_struct *tty, struct file *filp);
651 extern int tty_port_install(struct tty_port *port, struct tty_driver *driver,
652 				struct tty_struct *tty);
653 extern int tty_port_open(struct tty_port *port,
654 				struct tty_struct *tty, struct file *filp);
655 static inline int tty_port_users(struct tty_port *port)
656 {
657 	return port->count + port->blocked_open;
658 }
659 
660 extern int tty_register_ldisc(int disc, struct tty_ldisc_ops *new_ldisc);
661 extern int tty_unregister_ldisc(int disc);
662 extern int tty_set_ldisc(struct tty_struct *tty, int disc);
663 extern int tty_ldisc_setup(struct tty_struct *tty, struct tty_struct *o_tty);
664 extern void tty_ldisc_release(struct tty_struct *tty);
665 extern void tty_ldisc_init(struct tty_struct *tty);
666 extern void tty_ldisc_deinit(struct tty_struct *tty);
667 extern int tty_ldisc_receive_buf(struct tty_ldisc *ld, const unsigned char *p,
668 				 char *f, int count);
669 
670 /* n_tty.c */
671 extern void n_tty_inherit_ops(struct tty_ldisc_ops *ops);
672 extern void __init n_tty_init(void);
673 
674 /* tty_audit.c */
675 #ifdef CONFIG_AUDIT
676 extern void tty_audit_add_data(struct tty_struct *tty, const void *data,
677 			       size_t size);
678 extern void tty_audit_exit(void);
679 extern void tty_audit_fork(struct signal_struct *sig);
680 extern void tty_audit_tiocsti(struct tty_struct *tty, char ch);
681 extern int tty_audit_push(void);
682 #else
683 static inline void tty_audit_add_data(struct tty_struct *tty, const void *data,
684 				      size_t size)
685 {
686 }
687 static inline void tty_audit_tiocsti(struct tty_struct *tty, char ch)
688 {
689 }
690 static inline void tty_audit_exit(void)
691 {
692 }
693 static inline void tty_audit_fork(struct signal_struct *sig)
694 {
695 }
696 static inline int tty_audit_push(void)
697 {
698 	return 0;
699 }
700 #endif
701 
702 /* tty_ioctl.c */
703 extern int n_tty_ioctl_helper(struct tty_struct *tty, struct file *file,
704 		       unsigned int cmd, unsigned long arg);
705 extern long n_tty_compat_ioctl_helper(struct tty_struct *tty, struct file *file,
706 		       unsigned int cmd, unsigned long arg);
707 
708 /* vt.c */
709 
710 extern int vt_ioctl(struct tty_struct *tty,
711 		    unsigned int cmd, unsigned long arg);
712 
713 extern long vt_compat_ioctl(struct tty_struct *tty,
714 		     unsigned int cmd, unsigned long arg);
715 
716 /* tty_mutex.c */
717 /* functions for preparation of BKL removal */
718 extern void tty_lock(struct tty_struct *tty);
719 extern int  tty_lock_interruptible(struct tty_struct *tty);
720 extern void tty_unlock(struct tty_struct *tty);
721 extern void tty_lock_slave(struct tty_struct *tty);
722 extern void tty_unlock_slave(struct tty_struct *tty);
723 extern void tty_set_lock_subclass(struct tty_struct *tty);
724 
725 #ifdef CONFIG_PROC_FS
726 extern void proc_tty_register_driver(struct tty_driver *);
727 extern void proc_tty_unregister_driver(struct tty_driver *);
728 #else
729 static inline void proc_tty_register_driver(struct tty_driver *d) {}
730 static inline void proc_tty_unregister_driver(struct tty_driver *d) {}
731 #endif
732 
733 #define tty_msg(fn, tty, f, ...) \
734 	fn("%s %s: " f, tty_driver_name(tty), tty_name(tty), ##__VA_ARGS__)
735 
736 #define tty_debug(tty, f, ...)	tty_msg(pr_debug, tty, f, ##__VA_ARGS__)
737 #define tty_info(tty, f, ...)	tty_msg(pr_info, tty, f, ##__VA_ARGS__)
738 #define tty_notice(tty, f, ...)	tty_msg(pr_notice, tty, f, ##__VA_ARGS__)
739 #define tty_warn(tty, f, ...)	tty_msg(pr_warn, tty, f, ##__VA_ARGS__)
740 #define tty_err(tty, f, ...)	tty_msg(pr_err, tty, f, ##__VA_ARGS__)
741 
742 #define tty_info_ratelimited(tty, f, ...) \
743 		tty_msg(pr_info_ratelimited, tty, f, ##__VA_ARGS__)
744 
745 #endif
746