xref: /linux-6.15/include/linux/tty.h (revision dcd454af)
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 
14 
15 
16 /*
17  * (Note: the *_driver.minor_start values 1, 64, 128, 192 are
18  * hardcoded at present.)
19  */
20 #define NR_UNIX98_PTY_DEFAULT	4096      /* Default maximum for Unix98 ptys */
21 #define NR_UNIX98_PTY_RESERVE	1024	  /* Default reserve for main devpts */
22 #define NR_UNIX98_PTY_MAX	(1 << MINORBITS) /* Absolute limit */
23 
24 /*
25  * This character is the same as _POSIX_VDISABLE: it cannot be used as
26  * a c_cc[] character, but indicates that a particular special character
27  * isn't in use (eg VINTR has no character etc)
28  */
29 #define __DISABLED_CHAR '\0'
30 
31 struct tty_buffer {
32 	struct tty_buffer *next;
33 	char *char_buf_ptr;
34 	unsigned char *flag_buf_ptr;
35 	int used;
36 	int size;
37 	int commit;
38 	int read;
39 	/* Data points here */
40 	unsigned long data[0];
41 };
42 
43 /*
44  * We default to dicing tty buffer allocations to this many characters
45  * in order to avoid multiple page allocations. We know the size of
46  * tty_buffer itself but it must also be taken into account that the
47  * the buffer is 256 byte aligned. See tty_buffer_find for the allocation
48  * logic this must match
49  */
50 
51 #define TTY_BUFFER_PAGE	(((PAGE_SIZE - sizeof(struct tty_buffer)) / 2) & ~0xFF)
52 
53 
54 struct tty_bufhead {
55 	struct work_struct work;
56 	spinlock_t lock;
57 	struct tty_buffer *head;	/* Queue head */
58 	struct tty_buffer *tail;	/* Active buffer */
59 	struct tty_buffer *free;	/* Free queue head */
60 	int memory_used;		/* Buffer space used excluding
61 								free queue */
62 };
63 /*
64  * When a break, frame error, or parity error happens, these codes are
65  * stuffed into the flags buffer.
66  */
67 #define TTY_NORMAL	0
68 #define TTY_BREAK	1
69 #define TTY_FRAME	2
70 #define TTY_PARITY	3
71 #define TTY_OVERRUN	4
72 
73 #define INTR_CHAR(tty) ((tty)->termios.c_cc[VINTR])
74 #define QUIT_CHAR(tty) ((tty)->termios.c_cc[VQUIT])
75 #define ERASE_CHAR(tty) ((tty)->termios.c_cc[VERASE])
76 #define KILL_CHAR(tty) ((tty)->termios.c_cc[VKILL])
77 #define EOF_CHAR(tty) ((tty)->termios.c_cc[VEOF])
78 #define TIME_CHAR(tty) ((tty)->termios.c_cc[VTIME])
79 #define MIN_CHAR(tty) ((tty)->termios.c_cc[VMIN])
80 #define SWTC_CHAR(tty) ((tty)->termios.c_cc[VSWTC])
81 #define START_CHAR(tty) ((tty)->termios.c_cc[VSTART])
82 #define STOP_CHAR(tty) ((tty)->termios.c_cc[VSTOP])
83 #define SUSP_CHAR(tty) ((tty)->termios.c_cc[VSUSP])
84 #define EOL_CHAR(tty) ((tty)->termios.c_cc[VEOL])
85 #define REPRINT_CHAR(tty) ((tty)->termios.c_cc[VREPRINT])
86 #define DISCARD_CHAR(tty) ((tty)->termios.c_cc[VDISCARD])
87 #define WERASE_CHAR(tty) ((tty)->termios.c_cc[VWERASE])
88 #define LNEXT_CHAR(tty)	((tty)->termios.c_cc[VLNEXT])
89 #define EOL2_CHAR(tty) ((tty)->termios.c_cc[VEOL2])
90 
91 #define _I_FLAG(tty, f)	((tty)->termios.c_iflag & (f))
92 #define _O_FLAG(tty, f)	((tty)->termios.c_oflag & (f))
93 #define _C_FLAG(tty, f)	((tty)->termios.c_cflag & (f))
94 #define _L_FLAG(tty, f)	((tty)->termios.c_lflag & (f))
95 
96 #define I_IGNBRK(tty)	_I_FLAG((tty), IGNBRK)
97 #define I_BRKINT(tty)	_I_FLAG((tty), BRKINT)
98 #define I_IGNPAR(tty)	_I_FLAG((tty), IGNPAR)
99 #define I_PARMRK(tty)	_I_FLAG((tty), PARMRK)
100 #define I_INPCK(tty)	_I_FLAG((tty), INPCK)
101 #define I_ISTRIP(tty)	_I_FLAG((tty), ISTRIP)
102 #define I_INLCR(tty)	_I_FLAG((tty), INLCR)
103 #define I_IGNCR(tty)	_I_FLAG((tty), IGNCR)
104 #define I_ICRNL(tty)	_I_FLAG((tty), ICRNL)
105 #define I_IUCLC(tty)	_I_FLAG((tty), IUCLC)
106 #define I_IXON(tty)	_I_FLAG((tty), IXON)
107 #define I_IXANY(tty)	_I_FLAG((tty), IXANY)
108 #define I_IXOFF(tty)	_I_FLAG((tty), IXOFF)
109 #define I_IMAXBEL(tty)	_I_FLAG((tty), IMAXBEL)
110 #define I_IUTF8(tty)	_I_FLAG((tty), IUTF8)
111 
112 #define O_OPOST(tty)	_O_FLAG((tty), OPOST)
113 #define O_OLCUC(tty)	_O_FLAG((tty), OLCUC)
114 #define O_ONLCR(tty)	_O_FLAG((tty), ONLCR)
115 #define O_OCRNL(tty)	_O_FLAG((tty), OCRNL)
116 #define O_ONOCR(tty)	_O_FLAG((tty), ONOCR)
117 #define O_ONLRET(tty)	_O_FLAG((tty), ONLRET)
118 #define O_OFILL(tty)	_O_FLAG((tty), OFILL)
119 #define O_OFDEL(tty)	_O_FLAG((tty), OFDEL)
120 #define O_NLDLY(tty)	_O_FLAG((tty), NLDLY)
121 #define O_CRDLY(tty)	_O_FLAG((tty), CRDLY)
122 #define O_TABDLY(tty)	_O_FLAG((tty), TABDLY)
123 #define O_BSDLY(tty)	_O_FLAG((tty), BSDLY)
124 #define O_VTDLY(tty)	_O_FLAG((tty), VTDLY)
125 #define O_FFDLY(tty)	_O_FLAG((tty), FFDLY)
126 
127 #define C_BAUD(tty)	_C_FLAG((tty), CBAUD)
128 #define C_CSIZE(tty)	_C_FLAG((tty), CSIZE)
129 #define C_CSTOPB(tty)	_C_FLAG((tty), CSTOPB)
130 #define C_CREAD(tty)	_C_FLAG((tty), CREAD)
131 #define C_PARENB(tty)	_C_FLAG((tty), PARENB)
132 #define C_PARODD(tty)	_C_FLAG((tty), PARODD)
133 #define C_HUPCL(tty)	_C_FLAG((tty), HUPCL)
134 #define C_CLOCAL(tty)	_C_FLAG((tty), CLOCAL)
135 #define C_CIBAUD(tty)	_C_FLAG((tty), CIBAUD)
136 #define C_CRTSCTS(tty)	_C_FLAG((tty), CRTSCTS)
137 
138 #define L_ISIG(tty)	_L_FLAG((tty), ISIG)
139 #define L_ICANON(tty)	_L_FLAG((tty), ICANON)
140 #define L_XCASE(tty)	_L_FLAG((tty), XCASE)
141 #define L_ECHO(tty)	_L_FLAG((tty), ECHO)
142 #define L_ECHOE(tty)	_L_FLAG((tty), ECHOE)
143 #define L_ECHOK(tty)	_L_FLAG((tty), ECHOK)
144 #define L_ECHONL(tty)	_L_FLAG((tty), ECHONL)
145 #define L_NOFLSH(tty)	_L_FLAG((tty), NOFLSH)
146 #define L_TOSTOP(tty)	_L_FLAG((tty), TOSTOP)
147 #define L_ECHOCTL(tty)	_L_FLAG((tty), ECHOCTL)
148 #define L_ECHOPRT(tty)	_L_FLAG((tty), ECHOPRT)
149 #define L_ECHOKE(tty)	_L_FLAG((tty), ECHOKE)
150 #define L_FLUSHO(tty)	_L_FLAG((tty), FLUSHO)
151 #define L_PENDIN(tty)	_L_FLAG((tty), PENDIN)
152 #define L_IEXTEN(tty)	_L_FLAG((tty), IEXTEN)
153 #define L_EXTPROC(tty)	_L_FLAG((tty), EXTPROC)
154 
155 struct device;
156 struct signal_struct;
157 
158 /*
159  * Port level information. Each device keeps its own port level information
160  * so provide a common structure for those ports wanting to use common support
161  * routines.
162  *
163  * The tty port has a different lifetime to the tty so must be kept apart.
164  * In addition be careful as tty -> port mappings are valid for the life
165  * of the tty object but in many cases port -> tty mappings are valid only
166  * until a hangup so don't use the wrong path.
167  */
168 
169 struct tty_port;
170 
171 struct tty_port_operations {
172 	/* Return 1 if the carrier is raised */
173 	int (*carrier_raised)(struct tty_port *port);
174 	/* Control the DTR line */
175 	void (*dtr_rts)(struct tty_port *port, int raise);
176 	/* Called when the last close completes or a hangup finishes
177 	   IFF the port was initialized. Do not use to free resources. Called
178 	   under the port mutex to serialize against activate/shutdowns */
179 	void (*shutdown)(struct tty_port *port);
180 	void (*drop)(struct tty_port *port);
181 	/* Called under the port mutex from tty_port_open, serialized using
182 	   the port mutex */
183         /* FIXME: long term getting the tty argument *out* of this would be
184            good for consoles */
185 	int (*activate)(struct tty_port *port, struct tty_struct *tty);
186 	/* Called on the final put of a port */
187 	void (*destruct)(struct tty_port *port);
188 };
189 
190 struct tty_port {
191 	struct tty_bufhead	buf;		/* Locked internally */
192 	struct tty_struct	*tty;		/* Back pointer */
193 	struct tty_struct	*itty;		/* internal back ptr */
194 	const struct tty_port_operations *ops;	/* Port operations */
195 	spinlock_t		lock;		/* Lock protecting tty field */
196 	int			blocked_open;	/* Waiting to open */
197 	int			count;		/* Usage count */
198 	wait_queue_head_t	open_wait;	/* Open waiters */
199 	wait_queue_head_t	close_wait;	/* Close waiters */
200 	wait_queue_head_t	delta_msr_wait;	/* Modem status change */
201 	unsigned long		flags;		/* TTY flags ASY_*/
202 	unsigned long		iflags;		/* TTYP_ internal flags */
203 #define TTYP_FLUSHING			1  /* Flushing to ldisc in progress */
204 #define TTYP_FLUSHPENDING		2  /* Queued buffer flush pending */
205 	unsigned char		console:1,	/* port is a console */
206 				low_latency:1;	/* direct buffer flush */
207 	struct mutex		mutex;		/* Locking */
208 	struct mutex		buf_mutex;	/* Buffer alloc lock */
209 	unsigned char		*xmit_buf;	/* Optional buffer */
210 	unsigned int		close_delay;	/* Close port delay */
211 	unsigned int		closing_wait;	/* Delay for output */
212 	int			drain_delay;	/* Set to zero if no pure time
213 						   based drain is needed else
214 						   set to size of fifo */
215 	struct kref		kref;		/* Ref counter */
216 };
217 
218 /*
219  * Where all of the state associated with a tty is kept while the tty
220  * is open.  Since the termios state should be kept even if the tty
221  * has been closed --- for things like the baud rate, etc --- it is
222  * not stored here, but rather a pointer to the real state is stored
223  * here.  Possible the winsize structure should have the same
224  * treatment, but (1) the default 80x24 is usually right and (2) it's
225  * most often used by a windowing system, which will set the correct
226  * size each time the window is created or resized anyway.
227  * 						- TYT, 9/14/92
228  */
229 
230 struct tty_operations;
231 
232 struct tty_struct {
233 	int	magic;
234 	struct kref kref;
235 	struct device *dev;
236 	struct tty_driver *driver;
237 	const struct tty_operations *ops;
238 	int index;
239 
240 	/* Protects ldisc changes: Lock tty not pty */
241 	struct mutex ldisc_mutex;
242 	struct tty_ldisc *ldisc;
243 
244 	struct mutex atomic_write_lock;
245 	struct mutex legacy_mutex;
246 	struct mutex termios_mutex;
247 	spinlock_t ctrl_lock;
248 	/* Termios values are protected by the termios mutex */
249 	struct ktermios termios, termios_locked;
250 	struct termiox *termiox;	/* May be NULL for unsupported */
251 	char name[64];
252 	struct pid *pgrp;		/* Protected by ctrl lock */
253 	struct pid *session;
254 	unsigned long flags;
255 	int count;
256 	struct winsize winsize;		/* termios mutex */
257 	unsigned char stopped:1, hw_stopped:1, flow_stopped:1, packet:1;
258 	unsigned char ctrl_status;	/* ctrl_lock */
259 	unsigned int receive_room;	/* Bytes free for queue */
260 	int flow_change;
261 
262 	struct tty_struct *link;
263 	struct fasync_struct *fasync;
264 	int alt_speed;		/* For magic substitution of 38400 bps */
265 	wait_queue_head_t write_wait;
266 	wait_queue_head_t read_wait;
267 	struct work_struct hangup_work;
268 	void *disc_data;
269 	void *driver_data;
270 	struct list_head tty_files;
271 
272 #define N_TTY_BUF_SIZE 4096
273 
274 	unsigned char closing:1;
275 	unsigned char *write_buf;
276 	int write_cnt;
277 	/* If the tty has a pending do_SAK, queue it here - akpm */
278 	struct work_struct SAK_work;
279 	struct tty_port *port;
280 };
281 
282 /* Each of a tty's open files has private_data pointing to tty_file_private */
283 struct tty_file_private {
284 	struct tty_struct *tty;
285 	struct file *file;
286 	struct list_head list;
287 };
288 
289 /* tty magic number */
290 #define TTY_MAGIC		0x5401
291 
292 /*
293  * These bits are used in the flags field of the tty structure.
294  *
295  * So that interrupts won't be able to mess up the queues,
296  * copy_to_cooked must be atomic with respect to itself, as must
297  * tty->write.  Thus, you must use the inline functions set_bit() and
298  * clear_bit() to make things atomic.
299  */
300 #define TTY_THROTTLED 		0	/* Call unthrottle() at threshold min */
301 #define TTY_IO_ERROR 		1	/* Cause an I/O error (may be no ldisc too) */
302 #define TTY_OTHER_CLOSED 	2	/* Other side (if any) has closed */
303 #define TTY_EXCLUSIVE 		3	/* Exclusive open mode */
304 #define TTY_DEBUG 		4	/* Debugging */
305 #define TTY_DO_WRITE_WAKEUP 	5	/* Call write_wakeup after queuing new */
306 #define TTY_PUSH 		6	/* n_tty private */
307 #define TTY_CLOSING 		7	/* ->close() in progress */
308 #define TTY_LDISC 		9	/* Line discipline attached */
309 #define TTY_LDISC_CHANGING 	10	/* Line discipline changing */
310 #define TTY_LDISC_OPEN	 	11	/* Line discipline is open */
311 #define TTY_PTY_LOCK 		16	/* pty private */
312 #define TTY_NO_WRITE_SPLIT 	17	/* Preserve write boundaries to driver */
313 #define TTY_HUPPED 		18	/* Post driver->hangup() */
314 #define TTY_HUPPING 		21	/* ->hangup() in progress */
315 #define TTY_LDISC_HALTED	22	/* Line discipline is halted */
316 
317 #define TTY_WRITE_FLUSH(tty) tty_write_flush((tty))
318 
319 /* Values for tty->flow_change */
320 #define TTY_THROTTLE_SAFE 1
321 #define TTY_UNTHROTTLE_SAFE 2
322 
323 static inline void __tty_set_flow_change(struct tty_struct *tty, int val)
324 {
325 	tty->flow_change = val;
326 }
327 
328 static inline void tty_set_flow_change(struct tty_struct *tty, int val)
329 {
330 	tty->flow_change = val;
331 	smp_mb();
332 }
333 
334 #ifdef CONFIG_TTY
335 extern void console_init(void);
336 extern void tty_kref_put(struct tty_struct *tty);
337 extern struct pid *tty_get_pgrp(struct tty_struct *tty);
338 extern void tty_vhangup_self(void);
339 extern void disassociate_ctty(int priv);
340 extern dev_t tty_devnum(struct tty_struct *tty);
341 extern void proc_clear_tty(struct task_struct *p);
342 extern struct tty_struct *get_current_tty(void);
343 /* tty_io.c */
344 extern int __init tty_init(void);
345 #else
346 static inline void console_init(void)
347 { }
348 static inline void tty_kref_put(struct tty_struct *tty)
349 { }
350 static inline struct pid *tty_get_pgrp(struct tty_struct *tty)
351 { return NULL; }
352 static inline void tty_vhangup_self(void)
353 { }
354 static inline void disassociate_ctty(int priv)
355 { }
356 static inline dev_t tty_devnum(struct tty_struct *tty)
357 { return 0; }
358 static inline void proc_clear_tty(struct task_struct *p)
359 { }
360 static inline struct tty_struct *get_current_tty(void)
361 { return NULL; }
362 /* tty_io.c */
363 static inline int __init tty_init(void)
364 { return 0; }
365 #endif
366 
367 extern void tty_write_flush(struct tty_struct *);
368 
369 extern struct ktermios tty_std_termios;
370 
371 extern int vcs_init(void);
372 
373 extern struct class *tty_class;
374 
375 /**
376  *	tty_kref_get		-	get a tty reference
377  *	@tty: tty device
378  *
379  *	Return a new reference to a tty object. The caller must hold
380  *	sufficient locks/counts to ensure that their existing reference cannot
381  *	go away
382  */
383 
384 static inline struct tty_struct *tty_kref_get(struct tty_struct *tty)
385 {
386 	if (tty)
387 		kref_get(&tty->kref);
388 	return tty;
389 }
390 
391 extern int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
392 			      const char *routine);
393 extern char *tty_name(struct tty_struct *tty, char *buf);
394 extern void tty_wait_until_sent(struct tty_struct *tty, long timeout);
395 extern int tty_check_change(struct tty_struct *tty);
396 extern void stop_tty(struct tty_struct *tty);
397 extern void start_tty(struct tty_struct *tty);
398 extern int tty_register_driver(struct tty_driver *driver);
399 extern int tty_unregister_driver(struct tty_driver *driver);
400 extern struct device *tty_register_device(struct tty_driver *driver,
401 					  unsigned index, struct device *dev);
402 extern struct device *tty_register_device_attr(struct tty_driver *driver,
403 				unsigned index, struct device *device,
404 				void *drvdata,
405 				const struct attribute_group **attr_grp);
406 extern void tty_unregister_device(struct tty_driver *driver, unsigned index);
407 extern int tty_read_raw_data(struct tty_struct *tty, unsigned char *bufp,
408 			     int buflen);
409 extern void tty_write_message(struct tty_struct *tty, char *msg);
410 extern int tty_put_char(struct tty_struct *tty, unsigned char c);
411 extern int tty_chars_in_buffer(struct tty_struct *tty);
412 extern int tty_write_room(struct tty_struct *tty);
413 extern void tty_driver_flush_buffer(struct tty_struct *tty);
414 extern void tty_throttle(struct tty_struct *tty);
415 extern void tty_unthrottle(struct tty_struct *tty);
416 extern int tty_throttle_safe(struct tty_struct *tty);
417 extern int tty_unthrottle_safe(struct tty_struct *tty);
418 extern int tty_do_resize(struct tty_struct *tty, struct winsize *ws);
419 extern void tty_driver_remove_tty(struct tty_driver *driver,
420 				  struct tty_struct *tty);
421 extern void tty_free_termios(struct tty_struct *tty);
422 extern int is_current_pgrp_orphaned(void);
423 extern int is_ignored(int sig);
424 extern int tty_signal(int sig, struct tty_struct *tty);
425 extern void tty_hangup(struct tty_struct *tty);
426 extern void tty_vhangup(struct tty_struct *tty);
427 extern void tty_vhangup_locked(struct tty_struct *tty);
428 extern void tty_unhangup(struct file *filp);
429 extern int tty_hung_up_p(struct file *filp);
430 extern void do_SAK(struct tty_struct *tty);
431 extern void __do_SAK(struct tty_struct *tty);
432 extern void no_tty(void);
433 extern void tty_flush_to_ldisc(struct tty_struct *tty);
434 extern void tty_buffer_free_all(struct tty_port *port);
435 extern void tty_buffer_flush(struct tty_struct *tty);
436 extern void tty_buffer_init(struct tty_port *port);
437 extern speed_t tty_termios_baud_rate(struct ktermios *termios);
438 extern speed_t tty_termios_input_baud_rate(struct ktermios *termios);
439 extern void tty_termios_encode_baud_rate(struct ktermios *termios,
440 						speed_t ibaud, speed_t obaud);
441 extern void tty_encode_baud_rate(struct tty_struct *tty,
442 						speed_t ibaud, speed_t obaud);
443 
444 /**
445  *	tty_get_baud_rate	-	get tty bit rates
446  *	@tty: tty to query
447  *
448  *	Returns the baud rate as an integer for this terminal. The
449  *	termios lock must be held by the caller and the terminal bit
450  *	flags may be updated.
451  *
452  *	Locking: none
453  */
454 static inline speed_t tty_get_baud_rate(struct tty_struct *tty)
455 {
456 	return tty_termios_baud_rate(&tty->termios);
457 }
458 
459 extern void tty_termios_copy_hw(struct ktermios *new, struct ktermios *old);
460 extern int tty_termios_hw_change(struct ktermios *a, struct ktermios *b);
461 extern int tty_set_termios(struct tty_struct *tty, struct ktermios *kt);
462 
463 extern struct tty_ldisc *tty_ldisc_ref(struct tty_struct *);
464 extern void tty_ldisc_deref(struct tty_ldisc *);
465 extern struct tty_ldisc *tty_ldisc_ref_wait(struct tty_struct *);
466 extern void tty_ldisc_hangup(struct tty_struct *tty);
467 extern const struct file_operations tty_ldiscs_proc_fops;
468 
469 extern void tty_wakeup(struct tty_struct *tty);
470 extern void tty_ldisc_flush(struct tty_struct *tty);
471 
472 extern long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
473 extern int tty_mode_ioctl(struct tty_struct *tty, struct file *file,
474 			unsigned int cmd, unsigned long arg);
475 extern int tty_perform_flush(struct tty_struct *tty, unsigned long arg);
476 extern void tty_default_fops(struct file_operations *fops);
477 extern struct tty_struct *alloc_tty_struct(void);
478 extern int tty_alloc_file(struct file *file);
479 extern void tty_add_file(struct tty_struct *tty, struct file *file);
480 extern void tty_free_file(struct file *file);
481 extern void free_tty_struct(struct tty_struct *tty);
482 extern void initialize_tty_struct(struct tty_struct *tty,
483 		struct tty_driver *driver, int idx);
484 extern void deinitialize_tty_struct(struct tty_struct *tty);
485 extern struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx);
486 extern int tty_release(struct inode *inode, struct file *filp);
487 extern int tty_init_termios(struct tty_struct *tty);
488 extern int tty_standard_install(struct tty_driver *driver,
489 		struct tty_struct *tty);
490 
491 extern struct tty_struct *tty_pair_get_tty(struct tty_struct *tty);
492 extern struct tty_struct *tty_pair_get_pty(struct tty_struct *tty);
493 
494 extern struct mutex tty_mutex;
495 extern spinlock_t tty_files_lock;
496 
497 extern void tty_write_unlock(struct tty_struct *tty);
498 extern int tty_write_lock(struct tty_struct *tty, int ndelay);
499 #define tty_is_writelocked(tty)  (mutex_is_locked(&tty->atomic_write_lock))
500 
501 extern void tty_port_init(struct tty_port *port);
502 extern void tty_port_link_device(struct tty_port *port,
503 		struct tty_driver *driver, unsigned index);
504 extern struct device *tty_port_register_device(struct tty_port *port,
505 		struct tty_driver *driver, unsigned index,
506 		struct device *device);
507 extern struct device *tty_port_register_device_attr(struct tty_port *port,
508 		struct tty_driver *driver, unsigned index,
509 		struct device *device, void *drvdata,
510 		const struct attribute_group **attr_grp);
511 extern int tty_port_alloc_xmit_buf(struct tty_port *port);
512 extern void tty_port_free_xmit_buf(struct tty_port *port);
513 extern void tty_port_destroy(struct tty_port *port);
514 extern void tty_port_put(struct tty_port *port);
515 
516 static inline struct tty_port *tty_port_get(struct tty_port *port)
517 {
518 	if (port)
519 		kref_get(&port->kref);
520 	return port;
521 }
522 
523 /* If the cts flow control is enabled, return true. */
524 static inline bool tty_port_cts_enabled(struct tty_port *port)
525 {
526 	return port->flags & ASYNC_CTS_FLOW;
527 }
528 
529 extern struct tty_struct *tty_port_tty_get(struct tty_port *port);
530 extern void tty_port_tty_set(struct tty_port *port, struct tty_struct *tty);
531 extern int tty_port_carrier_raised(struct tty_port *port);
532 extern void tty_port_raise_dtr_rts(struct tty_port *port);
533 extern void tty_port_lower_dtr_rts(struct tty_port *port);
534 extern void tty_port_hangup(struct tty_port *port);
535 extern void tty_port_tty_hangup(struct tty_port *port, bool check_clocal);
536 extern void tty_port_tty_wakeup(struct tty_port *port);
537 extern int tty_port_block_til_ready(struct tty_port *port,
538 				struct tty_struct *tty, struct file *filp);
539 extern int tty_port_close_start(struct tty_port *port,
540 				struct tty_struct *tty, struct file *filp);
541 extern void tty_port_close_end(struct tty_port *port, struct tty_struct *tty);
542 extern void tty_port_close(struct tty_port *port,
543 				struct tty_struct *tty, struct file *filp);
544 extern int tty_port_install(struct tty_port *port, struct tty_driver *driver,
545 				struct tty_struct *tty);
546 extern int tty_port_open(struct tty_port *port,
547 				struct tty_struct *tty, struct file *filp);
548 static inline int tty_port_users(struct tty_port *port)
549 {
550 	return port->count + port->blocked_open;
551 }
552 
553 extern int tty_register_ldisc(int disc, struct tty_ldisc_ops *new_ldisc);
554 extern int tty_unregister_ldisc(int disc);
555 extern int tty_set_ldisc(struct tty_struct *tty, int ldisc);
556 extern int tty_ldisc_setup(struct tty_struct *tty, struct tty_struct *o_tty);
557 extern void tty_ldisc_release(struct tty_struct *tty, struct tty_struct *o_tty);
558 extern void tty_ldisc_init(struct tty_struct *tty);
559 extern void tty_ldisc_deinit(struct tty_struct *tty);
560 extern void tty_ldisc_begin(void);
561 
562 
563 /* n_tty.c */
564 extern struct tty_ldisc_ops tty_ldisc_N_TTY;
565 extern void n_tty_inherit_ops(struct tty_ldisc_ops *ops);
566 
567 /* tty_audit.c */
568 #ifdef CONFIG_AUDIT
569 extern void tty_audit_add_data(struct tty_struct *tty, unsigned char *data,
570 			       size_t size, unsigned icanon);
571 extern void tty_audit_exit(void);
572 extern void tty_audit_fork(struct signal_struct *sig);
573 extern void tty_audit_tiocsti(struct tty_struct *tty, char ch);
574 extern void tty_audit_push(struct tty_struct *tty);
575 extern int tty_audit_push_current(void);
576 #else
577 static inline void tty_audit_add_data(struct tty_struct *tty,
578 		unsigned char *data, size_t size, unsigned icanon)
579 {
580 }
581 static inline void tty_audit_tiocsti(struct tty_struct *tty, char ch)
582 {
583 }
584 static inline void tty_audit_exit(void)
585 {
586 }
587 static inline void tty_audit_fork(struct signal_struct *sig)
588 {
589 }
590 static inline void tty_audit_push(struct tty_struct *tty)
591 {
592 }
593 static inline int tty_audit_push_current(void)
594 {
595 	return 0;
596 }
597 #endif
598 
599 /* tty_ioctl.c */
600 extern int n_tty_ioctl_helper(struct tty_struct *tty, struct file *file,
601 		       unsigned int cmd, unsigned long arg);
602 extern long n_tty_compat_ioctl_helper(struct tty_struct *tty, struct file *file,
603 		       unsigned int cmd, unsigned long arg);
604 
605 /* serial.c */
606 
607 extern void serial_console_init(void);
608 
609 /* pcxx.c */
610 
611 extern int pcxe_open(struct tty_struct *tty, struct file *filp);
612 
613 /* vt.c */
614 
615 extern int vt_ioctl(struct tty_struct *tty,
616 		    unsigned int cmd, unsigned long arg);
617 
618 extern long vt_compat_ioctl(struct tty_struct *tty,
619 		     unsigned int cmd, unsigned long arg);
620 
621 /* tty_mutex.c */
622 /* functions for preparation of BKL removal */
623 extern void __lockfunc tty_lock(struct tty_struct *tty);
624 extern void __lockfunc tty_unlock(struct tty_struct *tty);
625 extern void __lockfunc tty_lock_pair(struct tty_struct *tty,
626 				struct tty_struct *tty2);
627 extern void __lockfunc tty_unlock_pair(struct tty_struct *tty,
628 				struct tty_struct *tty2);
629 
630 /*
631  * this shall be called only from where BTM is held (like close)
632  *
633  * We need this to ensure nobody waits for us to finish while we are waiting.
634  * Without this we were encountering system stalls.
635  *
636  * This should be indeed removed with BTM removal later.
637  *
638  * Locking: BTM required. Nobody is allowed to hold port->mutex.
639  */
640 static inline void tty_wait_until_sent_from_close(struct tty_struct *tty,
641 		long timeout)
642 {
643 	tty_unlock(tty); /* tty->ops->close holds the BTM, drop it while waiting */
644 	tty_wait_until_sent(tty, timeout);
645 	tty_lock(tty);
646 }
647 
648 /*
649  * wait_event_interruptible_tty -- wait for a condition with the tty lock held
650  *
651  * The condition we are waiting for might take a long time to
652  * become true, or might depend on another thread taking the
653  * BTM. In either case, we need to drop the BTM to guarantee
654  * forward progress. This is a leftover from the conversion
655  * from the BKL and should eventually get removed as the BTM
656  * falls out of use.
657  *
658  * Do not use in new code.
659  */
660 #define wait_event_interruptible_tty(tty, wq, condition)		\
661 ({									\
662 	int __ret = 0;							\
663 	if (!(condition)) {						\
664 		__wait_event_interruptible_tty(tty, wq, condition, __ret);	\
665 	}								\
666 	__ret;								\
667 })
668 
669 #define __wait_event_interruptible_tty(tty, wq, condition, ret)		\
670 do {									\
671 	DEFINE_WAIT(__wait);						\
672 									\
673 	for (;;) {							\
674 		prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE);	\
675 		if (condition)						\
676 			break;						\
677 		if (!signal_pending(current)) {				\
678 			tty_unlock(tty);					\
679 			schedule();					\
680 			tty_lock(tty);					\
681 			continue;					\
682 		}							\
683 		ret = -ERESTARTSYS;					\
684 		break;							\
685 	}								\
686 	finish_wait(&wq, &__wait);					\
687 } while (0)
688 
689 #ifdef CONFIG_PROC_FS
690 extern void proc_tty_register_driver(struct tty_driver *);
691 extern void proc_tty_unregister_driver(struct tty_driver *);
692 #else
693 static inline void proc_tty_register_driver(struct tty_driver *d) {}
694 static inline void proc_tty_unregister_driver(struct tty_driver *d) {}
695 #endif
696 
697 #endif
698