xref: /linux-6.15/include/linux/tty.h (revision 5bf2b193)
1 #ifndef _LINUX_TTY_H
2 #define _LINUX_TTY_H
3 
4 /*
5  * 'tty.h' defines some structures used by tty_io.c and some defines.
6  */
7 
8 #ifdef __KERNEL__
9 #include <linux/fs.h>
10 #include <linux/major.h>
11 #include <linux/termios.h>
12 #include <linux/workqueue.h>
13 #include <linux/tty_driver.h>
14 #include <linux/tty_ldisc.h>
15 #include <linux/mutex.h>
16 #include <linux/smp_lock.h>
17 
18 #include <asm/system.h>
19 
20 
21 /*
22  * (Note: the *_driver.minor_start values 1, 64, 128, 192 are
23  * hardcoded at present.)
24  */
25 #define NR_UNIX98_PTY_DEFAULT	4096      /* Default maximum for Unix98 ptys */
26 #define NR_UNIX98_PTY_MAX	(1 << MINORBITS) /* Absolute limit */
27 #define NR_LDISCS		30
28 
29 /* line disciplines */
30 #define N_TTY		0
31 #define N_SLIP		1
32 #define N_MOUSE		2
33 #define N_PPP		3
34 #define N_STRIP		4
35 #define N_AX25		5
36 #define N_X25		6	/* X.25 async */
37 #define N_6PACK		7
38 #define N_MASC		8	/* Reserved for Mobitex module <[email protected]> */
39 #define N_R3964		9	/* Reserved for Simatic R3964 module */
40 #define N_PROFIBUS_FDL	10	/* Reserved for Profibus */
41 #define N_IRDA		11	/* Linux IrDa - http://irda.sourceforge.net/ */
42 #define N_SMSBLOCK	12	/* SMS block mode - for talking to GSM data */
43 				/* cards about SMS messages */
44 #define N_HDLC		13	/* synchronous HDLC */
45 #define N_SYNC_PPP	14	/* synchronous PPP */
46 #define N_HCI		15	/* Bluetooth HCI UART */
47 #define N_GIGASET_M101	16	/* Siemens Gigaset M101 serial DECT adapter */
48 #define N_SLCAN		17	/* Serial / USB serial CAN Adaptors */
49 #define N_PPS		18	/* Pulse per Second */
50 #define N_V253		19	/* Codec control over voice modem */
51 #define N_CAIF		20      /* CAIF protocol for talking to modems */
52 #define N_GSM0710	21	/* GSM 0710 Mux */
53 
54 /*
55  * This character is the same as _POSIX_VDISABLE: it cannot be used as
56  * a c_cc[] character, but indicates that a particular special character
57  * isn't in use (eg VINTR has no character etc)
58  */
59 #define __DISABLED_CHAR '\0'
60 
61 struct tty_buffer {
62 	struct tty_buffer *next;
63 	char *char_buf_ptr;
64 	unsigned char *flag_buf_ptr;
65 	int used;
66 	int size;
67 	int commit;
68 	int read;
69 	/* Data points here */
70 	unsigned long data[0];
71 };
72 
73 /*
74  * We default to dicing tty buffer allocations to this many characters
75  * in order to avoid multiple page allocations. We know the size of
76  * tty_buffer itself but it must also be taken into account that the
77  * the buffer is 256 byte aligned. See tty_buffer_find for the allocation
78  * logic this must match
79  */
80 
81 #define TTY_BUFFER_PAGE	(((PAGE_SIZE - sizeof(struct tty_buffer)) / 2) & ~0xFF)
82 
83 
84 struct tty_bufhead {
85 	struct delayed_work work;
86 	spinlock_t lock;
87 	struct tty_buffer *head;	/* Queue head */
88 	struct tty_buffer *tail;	/* Active buffer */
89 	struct tty_buffer *free;	/* Free queue head */
90 	int memory_used;		/* Buffer space used excluding
91 								free queue */
92 };
93 /*
94  * When a break, frame error, or parity error happens, these codes are
95  * stuffed into the flags buffer.
96  */
97 #define TTY_NORMAL	0
98 #define TTY_BREAK	1
99 #define TTY_FRAME	2
100 #define TTY_PARITY	3
101 #define TTY_OVERRUN	4
102 
103 #define INTR_CHAR(tty) ((tty)->termios->c_cc[VINTR])
104 #define QUIT_CHAR(tty) ((tty)->termios->c_cc[VQUIT])
105 #define ERASE_CHAR(tty) ((tty)->termios->c_cc[VERASE])
106 #define KILL_CHAR(tty) ((tty)->termios->c_cc[VKILL])
107 #define EOF_CHAR(tty) ((tty)->termios->c_cc[VEOF])
108 #define TIME_CHAR(tty) ((tty)->termios->c_cc[VTIME])
109 #define MIN_CHAR(tty) ((tty)->termios->c_cc[VMIN])
110 #define SWTC_CHAR(tty) ((tty)->termios->c_cc[VSWTC])
111 #define START_CHAR(tty) ((tty)->termios->c_cc[VSTART])
112 #define STOP_CHAR(tty) ((tty)->termios->c_cc[VSTOP])
113 #define SUSP_CHAR(tty) ((tty)->termios->c_cc[VSUSP])
114 #define EOL_CHAR(tty) ((tty)->termios->c_cc[VEOL])
115 #define REPRINT_CHAR(tty) ((tty)->termios->c_cc[VREPRINT])
116 #define DISCARD_CHAR(tty) ((tty)->termios->c_cc[VDISCARD])
117 #define WERASE_CHAR(tty) ((tty)->termios->c_cc[VWERASE])
118 #define LNEXT_CHAR(tty)	((tty)->termios->c_cc[VLNEXT])
119 #define EOL2_CHAR(tty) ((tty)->termios->c_cc[VEOL2])
120 
121 #define _I_FLAG(tty, f)	((tty)->termios->c_iflag & (f))
122 #define _O_FLAG(tty, f)	((tty)->termios->c_oflag & (f))
123 #define _C_FLAG(tty, f)	((tty)->termios->c_cflag & (f))
124 #define _L_FLAG(tty, f)	((tty)->termios->c_lflag & (f))
125 
126 #define I_IGNBRK(tty)	_I_FLAG((tty), IGNBRK)
127 #define I_BRKINT(tty)	_I_FLAG((tty), BRKINT)
128 #define I_IGNPAR(tty)	_I_FLAG((tty), IGNPAR)
129 #define I_PARMRK(tty)	_I_FLAG((tty), PARMRK)
130 #define I_INPCK(tty)	_I_FLAG((tty), INPCK)
131 #define I_ISTRIP(tty)	_I_FLAG((tty), ISTRIP)
132 #define I_INLCR(tty)	_I_FLAG((tty), INLCR)
133 #define I_IGNCR(tty)	_I_FLAG((tty), IGNCR)
134 #define I_ICRNL(tty)	_I_FLAG((tty), ICRNL)
135 #define I_IUCLC(tty)	_I_FLAG((tty), IUCLC)
136 #define I_IXON(tty)	_I_FLAG((tty), IXON)
137 #define I_IXANY(tty)	_I_FLAG((tty), IXANY)
138 #define I_IXOFF(tty)	_I_FLAG((tty), IXOFF)
139 #define I_IMAXBEL(tty)	_I_FLAG((tty), IMAXBEL)
140 #define I_IUTF8(tty)	_I_FLAG((tty), IUTF8)
141 
142 #define O_OPOST(tty)	_O_FLAG((tty), OPOST)
143 #define O_OLCUC(tty)	_O_FLAG((tty), OLCUC)
144 #define O_ONLCR(tty)	_O_FLAG((tty), ONLCR)
145 #define O_OCRNL(tty)	_O_FLAG((tty), OCRNL)
146 #define O_ONOCR(tty)	_O_FLAG((tty), ONOCR)
147 #define O_ONLRET(tty)	_O_FLAG((tty), ONLRET)
148 #define O_OFILL(tty)	_O_FLAG((tty), OFILL)
149 #define O_OFDEL(tty)	_O_FLAG((tty), OFDEL)
150 #define O_NLDLY(tty)	_O_FLAG((tty), NLDLY)
151 #define O_CRDLY(tty)	_O_FLAG((tty), CRDLY)
152 #define O_TABDLY(tty)	_O_FLAG((tty), TABDLY)
153 #define O_BSDLY(tty)	_O_FLAG((tty), BSDLY)
154 #define O_VTDLY(tty)	_O_FLAG((tty), VTDLY)
155 #define O_FFDLY(tty)	_O_FLAG((tty), FFDLY)
156 
157 #define C_BAUD(tty)	_C_FLAG((tty), CBAUD)
158 #define C_CSIZE(tty)	_C_FLAG((tty), CSIZE)
159 #define C_CSTOPB(tty)	_C_FLAG((tty), CSTOPB)
160 #define C_CREAD(tty)	_C_FLAG((tty), CREAD)
161 #define C_PARENB(tty)	_C_FLAG((tty), PARENB)
162 #define C_PARODD(tty)	_C_FLAG((tty), PARODD)
163 #define C_HUPCL(tty)	_C_FLAG((tty), HUPCL)
164 #define C_CLOCAL(tty)	_C_FLAG((tty), CLOCAL)
165 #define C_CIBAUD(tty)	_C_FLAG((tty), CIBAUD)
166 #define C_CRTSCTS(tty)	_C_FLAG((tty), CRTSCTS)
167 
168 #define L_ISIG(tty)	_L_FLAG((tty), ISIG)
169 #define L_ICANON(tty)	_L_FLAG((tty), ICANON)
170 #define L_XCASE(tty)	_L_FLAG((tty), XCASE)
171 #define L_ECHO(tty)	_L_FLAG((tty), ECHO)
172 #define L_ECHOE(tty)	_L_FLAG((tty), ECHOE)
173 #define L_ECHOK(tty)	_L_FLAG((tty), ECHOK)
174 #define L_ECHONL(tty)	_L_FLAG((tty), ECHONL)
175 #define L_NOFLSH(tty)	_L_FLAG((tty), NOFLSH)
176 #define L_TOSTOP(tty)	_L_FLAG((tty), TOSTOP)
177 #define L_ECHOCTL(tty)	_L_FLAG((tty), ECHOCTL)
178 #define L_ECHOPRT(tty)	_L_FLAG((tty), ECHOPRT)
179 #define L_ECHOKE(tty)	_L_FLAG((tty), ECHOKE)
180 #define L_FLUSHO(tty)	_L_FLAG((tty), FLUSHO)
181 #define L_PENDIN(tty)	_L_FLAG((tty), PENDIN)
182 #define L_IEXTEN(tty)	_L_FLAG((tty), IEXTEN)
183 #define L_EXTPROC(tty)	_L_FLAG((tty), EXTPROC)
184 
185 struct device;
186 struct signal_struct;
187 
188 /*
189  * Port level information. Each device keeps its own port level information
190  * so provide a common structure for those ports wanting to use common support
191  * routines.
192  *
193  * The tty port has a different lifetime to the tty so must be kept apart.
194  * In addition be careful as tty -> port mappings are valid for the life
195  * of the tty object but in many cases port -> tty mappings are valid only
196  * until a hangup so don't use the wrong path.
197  */
198 
199 struct tty_port;
200 
201 struct tty_port_operations {
202 	/* Return 1 if the carrier is raised */
203 	int (*carrier_raised)(struct tty_port *port);
204 	/* Control the DTR line */
205 	void (*dtr_rts)(struct tty_port *port, int raise);
206 	/* Called when the last close completes or a hangup finishes
207 	   IFF the port was initialized. Do not use to free resources. Called
208 	   under the port mutex to serialize against activate/shutdowns */
209 	void (*shutdown)(struct tty_port *port);
210 	void (*drop)(struct tty_port *port);
211 	/* Called under the port mutex from tty_port_open, serialized using
212 	   the port mutex */
213         /* FIXME: long term getting the tty argument *out* of this would be
214            good for consoles */
215 	int (*activate)(struct tty_port *port, struct tty_struct *tty);
216 	/* Called on the final put of a port */
217 	void (*destruct)(struct tty_port *port);
218 };
219 
220 struct tty_port {
221 	struct tty_struct	*tty;		/* Back pointer */
222 	const struct tty_port_operations *ops;	/* Port operations */
223 	spinlock_t		lock;		/* Lock protecting tty field */
224 	int			blocked_open;	/* Waiting to open */
225 	int			count;		/* Usage count */
226 	wait_queue_head_t	open_wait;	/* Open waiters */
227 	wait_queue_head_t	close_wait;	/* Close waiters */
228 	wait_queue_head_t	delta_msr_wait;	/* Modem status change */
229 	unsigned long		flags;		/* TTY flags ASY_*/
230 	unsigned char		console:1;	/* port is a console */
231 	struct mutex		mutex;		/* Locking */
232 	struct mutex		buf_mutex;	/* Buffer alloc lock */
233 	unsigned char		*xmit_buf;	/* Optional buffer */
234 	unsigned int		close_delay;	/* Close port delay */
235 	unsigned int		closing_wait;	/* Delay for output */
236 	int			drain_delay;	/* Set to zero if no pure time
237 						   based drain is needed else
238 						   set to size of fifo */
239 	struct kref		kref;		/* Ref counter */
240 };
241 
242 /*
243  * Where all of the state associated with a tty is kept while the tty
244  * is open.  Since the termios state should be kept even if the tty
245  * has been closed --- for things like the baud rate, etc --- it is
246  * not stored here, but rather a pointer to the real state is stored
247  * here.  Possible the winsize structure should have the same
248  * treatment, but (1) the default 80x24 is usually right and (2) it's
249  * most often used by a windowing system, which will set the correct
250  * size each time the window is created or resized anyway.
251  * 						- TYT, 9/14/92
252  */
253 
254 struct tty_operations;
255 
256 struct tty_struct {
257 	int	magic;
258 	struct kref kref;
259 	struct tty_driver *driver;
260 	const struct tty_operations *ops;
261 	int index;
262 
263 	/* Protects ldisc changes: Lock tty not pty */
264 	struct mutex ldisc_mutex;
265 	struct tty_ldisc *ldisc;
266 
267 	struct mutex termios_mutex;
268 	spinlock_t ctrl_lock;
269 	/* Termios values are protected by the termios mutex */
270 	struct ktermios *termios, *termios_locked;
271 	struct termiox *termiox;	/* May be NULL for unsupported */
272 	char name[64];
273 	struct pid *pgrp;		/* Protected by ctrl lock */
274 	struct pid *session;
275 	unsigned long flags;
276 	int count;
277 	struct winsize winsize;		/* termios mutex */
278 	unsigned char stopped:1, hw_stopped:1, flow_stopped:1, packet:1;
279 	unsigned char low_latency:1, warned:1;
280 	unsigned char ctrl_status;	/* ctrl_lock */
281 	unsigned int receive_room;	/* Bytes free for queue */
282 
283 	struct tty_struct *link;
284 	struct fasync_struct *fasync;
285 	struct tty_bufhead buf;		/* Locked internally */
286 	int alt_speed;		/* For magic substitution of 38400 bps */
287 	wait_queue_head_t write_wait;
288 	wait_queue_head_t read_wait;
289 	struct work_struct hangup_work;
290 	void *disc_data;
291 	void *driver_data;
292 	struct list_head tty_files;
293 
294 #define N_TTY_BUF_SIZE 4096
295 
296 	/*
297 	 * The following is data for the N_TTY line discipline.  For
298 	 * historical reasons, this is included in the tty structure.
299 	 * Mostly locked by the BKL.
300 	 */
301 	unsigned int column;
302 	unsigned char lnext:1, erasing:1, raw:1, real_raw:1, icanon:1;
303 	unsigned char closing:1;
304 	unsigned char echo_overrun:1;
305 	unsigned short minimum_to_wake;
306 	unsigned long overrun_time;
307 	int num_overrun;
308 	unsigned long process_char_map[256/(8*sizeof(unsigned long))];
309 	char *read_buf;
310 	int read_head;
311 	int read_tail;
312 	int read_cnt;
313 	unsigned long read_flags[N_TTY_BUF_SIZE/(8*sizeof(unsigned long))];
314 	unsigned char *echo_buf;
315 	unsigned int echo_pos;
316 	unsigned int echo_cnt;
317 	int canon_data;
318 	unsigned long canon_head;
319 	unsigned int canon_column;
320 	struct mutex atomic_read_lock;
321 	struct mutex atomic_write_lock;
322 	struct mutex output_lock;
323 	struct mutex echo_lock;
324 	unsigned char *write_buf;
325 	int write_cnt;
326 	spinlock_t read_lock;
327 	/* If the tty has a pending do_SAK, queue it here - akpm */
328 	struct work_struct SAK_work;
329 	struct tty_port *port;
330 };
331 
332 /* tty magic number */
333 #define TTY_MAGIC		0x5401
334 
335 /*
336  * These bits are used in the flags field of the tty structure.
337  *
338  * So that interrupts won't be able to mess up the queues,
339  * copy_to_cooked must be atomic with respect to itself, as must
340  * tty->write.  Thus, you must use the inline functions set_bit() and
341  * clear_bit() to make things atomic.
342  */
343 #define TTY_THROTTLED 		0	/* Call unthrottle() at threshold min */
344 #define TTY_IO_ERROR 		1	/* Cause an I/O error (may be no ldisc too) */
345 #define TTY_OTHER_CLOSED 	2	/* Other side (if any) has closed */
346 #define TTY_EXCLUSIVE 		3	/* Exclusive open mode */
347 #define TTY_DEBUG 		4	/* Debugging */
348 #define TTY_DO_WRITE_WAKEUP 	5	/* Call write_wakeup after queuing new */
349 #define TTY_PUSH 		6	/* n_tty private */
350 #define TTY_CLOSING 		7	/* ->close() in progress */
351 #define TTY_LDISC 		9	/* Line discipline attached */
352 #define TTY_LDISC_CHANGING 	10	/* Line discipline changing */
353 #define TTY_LDISC_OPEN	 	11	/* Line discipline is open */
354 #define TTY_HW_COOK_OUT 	14	/* Hardware can do output cooking */
355 #define TTY_HW_COOK_IN 		15	/* Hardware can do input cooking */
356 #define TTY_PTY_LOCK 		16	/* pty private */
357 #define TTY_NO_WRITE_SPLIT 	17	/* Preserve write boundaries to driver */
358 #define TTY_HUPPED 		18	/* Post driver->hangup() */
359 #define TTY_FLUSHING		19	/* Flushing to ldisc in progress */
360 #define TTY_FLUSHPENDING	20	/* Queued buffer flush pending */
361 
362 #define TTY_WRITE_FLUSH(tty) tty_write_flush((tty))
363 
364 extern void tty_write_flush(struct tty_struct *);
365 
366 extern struct ktermios tty_std_termios;
367 
368 extern void console_init(void);
369 extern int vcs_init(void);
370 
371 extern struct class *tty_class;
372 
373 /**
374  *	tty_kref_get		-	get a tty reference
375  *	@tty: tty device
376  *
377  *	Return a new reference to a tty object. The caller must hold
378  *	sufficient locks/counts to ensure that their existing reference cannot
379  *	go away
380  */
381 
382 static inline struct tty_struct *tty_kref_get(struct tty_struct *tty)
383 {
384 	if (tty)
385 		kref_get(&tty->kref);
386 	return tty;
387 }
388 extern void tty_kref_put(struct tty_struct *tty);
389 
390 extern int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
391 			      const char *routine);
392 extern char *tty_name(struct tty_struct *tty, char *buf);
393 extern void tty_wait_until_sent(struct tty_struct *tty, long timeout);
394 extern int tty_check_change(struct tty_struct *tty);
395 extern void stop_tty(struct tty_struct *tty);
396 extern void start_tty(struct tty_struct *tty);
397 extern int tty_register_driver(struct tty_driver *driver);
398 extern int tty_unregister_driver(struct tty_driver *driver);
399 extern struct device *tty_register_device(struct tty_driver *driver,
400 					  unsigned index, struct device *dev);
401 extern void tty_unregister_device(struct tty_driver *driver, unsigned index);
402 extern int tty_read_raw_data(struct tty_struct *tty, unsigned char *bufp,
403 			     int buflen);
404 extern void tty_write_message(struct tty_struct *tty, char *msg);
405 extern int tty_put_char(struct tty_struct *tty, unsigned char c);
406 extern int tty_chars_in_buffer(struct tty_struct *tty);
407 extern int tty_write_room(struct tty_struct *tty);
408 extern void tty_driver_flush_buffer(struct tty_struct *tty);
409 extern void tty_throttle(struct tty_struct *tty);
410 extern void tty_unthrottle(struct tty_struct *tty);
411 extern int tty_do_resize(struct tty_struct *tty, struct winsize *ws);
412 extern void tty_shutdown(struct tty_struct *tty);
413 extern void tty_free_termios(struct tty_struct *tty);
414 extern int is_current_pgrp_orphaned(void);
415 extern struct pid *tty_get_pgrp(struct tty_struct *tty);
416 extern int is_ignored(int sig);
417 extern int tty_signal(int sig, struct tty_struct *tty);
418 extern void tty_hangup(struct tty_struct *tty);
419 extern void tty_vhangup(struct tty_struct *tty);
420 extern void tty_vhangup_locked(struct tty_struct *tty);
421 extern void tty_vhangup_self(void);
422 extern void tty_unhangup(struct file *filp);
423 extern int tty_hung_up_p(struct file *filp);
424 extern void do_SAK(struct tty_struct *tty);
425 extern void __do_SAK(struct tty_struct *tty);
426 extern void disassociate_ctty(int priv);
427 extern void no_tty(void);
428 extern void tty_flip_buffer_push(struct tty_struct *tty);
429 extern void tty_flush_to_ldisc(struct tty_struct *tty);
430 extern void tty_buffer_free_all(struct tty_struct *tty);
431 extern void tty_buffer_flush(struct tty_struct *tty);
432 extern void tty_buffer_init(struct tty_struct *tty);
433 extern speed_t tty_get_baud_rate(struct tty_struct *tty);
434 extern speed_t tty_termios_baud_rate(struct ktermios *termios);
435 extern speed_t tty_termios_input_baud_rate(struct ktermios *termios);
436 extern void tty_termios_encode_baud_rate(struct ktermios *termios,
437 						speed_t ibaud, speed_t obaud);
438 extern void tty_encode_baud_rate(struct tty_struct *tty,
439 						speed_t ibaud, speed_t obaud);
440 extern void tty_termios_copy_hw(struct ktermios *new, struct ktermios *old);
441 extern int tty_termios_hw_change(struct ktermios *a, struct ktermios *b);
442 
443 extern struct tty_ldisc *tty_ldisc_ref(struct tty_struct *);
444 extern void tty_ldisc_deref(struct tty_ldisc *);
445 extern struct tty_ldisc *tty_ldisc_ref_wait(struct tty_struct *);
446 extern void tty_ldisc_hangup(struct tty_struct *tty);
447 extern const struct file_operations tty_ldiscs_proc_fops;
448 
449 extern void tty_wakeup(struct tty_struct *tty);
450 extern void tty_ldisc_flush(struct tty_struct *tty);
451 
452 extern long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
453 extern int tty_mode_ioctl(struct tty_struct *tty, struct file *file,
454 			unsigned int cmd, unsigned long arg);
455 extern int tty_perform_flush(struct tty_struct *tty, unsigned long arg);
456 extern dev_t tty_devnum(struct tty_struct *tty);
457 extern void proc_clear_tty(struct task_struct *p);
458 extern struct tty_struct *get_current_tty(void);
459 extern void tty_default_fops(struct file_operations *fops);
460 extern struct tty_struct *alloc_tty_struct(void);
461 extern void free_tty_struct(struct tty_struct *tty);
462 extern void initialize_tty_struct(struct tty_struct *tty,
463 		struct tty_driver *driver, int idx);
464 extern struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx,
465 								int first_ok);
466 extern int tty_release(struct inode *inode, struct file *filp);
467 extern int tty_init_termios(struct tty_struct *tty);
468 
469 extern struct tty_struct *tty_pair_get_tty(struct tty_struct *tty);
470 extern struct tty_struct *tty_pair_get_pty(struct tty_struct *tty);
471 
472 extern struct mutex tty_mutex;
473 
474 extern void tty_write_unlock(struct tty_struct *tty);
475 extern int tty_write_lock(struct tty_struct *tty, int ndelay);
476 #define tty_is_writelocked(tty)  (mutex_is_locked(&tty->atomic_write_lock))
477 
478 extern void tty_port_init(struct tty_port *port);
479 extern int tty_port_alloc_xmit_buf(struct tty_port *port);
480 extern void tty_port_free_xmit_buf(struct tty_port *port);
481 extern void tty_port_put(struct tty_port *port);
482 
483 static inline struct tty_port *tty_port_get(struct tty_port *port)
484 {
485 	if (port)
486 		kref_get(&port->kref);
487 	return port;
488 }
489 
490 extern struct tty_struct *tty_port_tty_get(struct tty_port *port);
491 extern void tty_port_tty_set(struct tty_port *port, struct tty_struct *tty);
492 extern int tty_port_carrier_raised(struct tty_port *port);
493 extern void tty_port_raise_dtr_rts(struct tty_port *port);
494 extern void tty_port_lower_dtr_rts(struct tty_port *port);
495 extern void tty_port_hangup(struct tty_port *port);
496 extern int tty_port_block_til_ready(struct tty_port *port,
497 				struct tty_struct *tty, struct file *filp);
498 extern int tty_port_close_start(struct tty_port *port,
499 				struct tty_struct *tty, struct file *filp);
500 extern void tty_port_close_end(struct tty_port *port, struct tty_struct *tty);
501 extern void tty_port_close(struct tty_port *port,
502 				struct tty_struct *tty, struct file *filp);
503 extern int tty_port_open(struct tty_port *port,
504 				struct tty_struct *tty, struct file *filp);
505 static inline int tty_port_users(struct tty_port *port)
506 {
507 	return port->count + port->blocked_open;
508 }
509 
510 extern int tty_register_ldisc(int disc, struct tty_ldisc_ops *new_ldisc);
511 extern int tty_unregister_ldisc(int disc);
512 extern int tty_set_ldisc(struct tty_struct *tty, int ldisc);
513 extern int tty_ldisc_setup(struct tty_struct *tty, struct tty_struct *o_tty);
514 extern void tty_ldisc_release(struct tty_struct *tty, struct tty_struct *o_tty);
515 extern void tty_ldisc_init(struct tty_struct *tty);
516 extern void tty_ldisc_begin(void);
517 /* This last one is just for the tty layer internals and shouldn't be used elsewhere */
518 extern void tty_ldisc_enable(struct tty_struct *tty);
519 
520 
521 /* n_tty.c */
522 extern struct tty_ldisc_ops tty_ldisc_N_TTY;
523 extern void n_tty_inherit_ops(struct tty_ldisc_ops *ops);
524 
525 /* tty_audit.c */
526 #ifdef CONFIG_AUDIT
527 extern void tty_audit_add_data(struct tty_struct *tty, unsigned char *data,
528 			       size_t size);
529 extern void tty_audit_exit(void);
530 extern void tty_audit_fork(struct signal_struct *sig);
531 extern void tty_audit_tiocsti(struct tty_struct *tty, char ch);
532 extern void tty_audit_push(struct tty_struct *tty);
533 extern void tty_audit_push_task(struct task_struct *tsk,
534 					uid_t loginuid, u32 sessionid);
535 #else
536 static inline void tty_audit_add_data(struct tty_struct *tty,
537 				      unsigned char *data, size_t size)
538 {
539 }
540 static inline void tty_audit_tiocsti(struct tty_struct *tty, char ch)
541 {
542 }
543 static inline void tty_audit_exit(void)
544 {
545 }
546 static inline void tty_audit_fork(struct signal_struct *sig)
547 {
548 }
549 static inline void tty_audit_push(struct tty_struct *tty)
550 {
551 }
552 static inline void tty_audit_push_task(struct task_struct *tsk,
553 					uid_t loginuid, u32 sessionid)
554 {
555 }
556 #endif
557 
558 /* tty_io.c */
559 extern int __init tty_init(void);
560 
561 /* tty_ioctl.c */
562 extern int n_tty_ioctl_helper(struct tty_struct *tty, struct file *file,
563 		       unsigned int cmd, unsigned long arg);
564 
565 /* serial.c */
566 
567 extern void serial_console_init(void);
568 
569 /* pcxx.c */
570 
571 extern int pcxe_open(struct tty_struct *tty, struct file *filp);
572 
573 /* vt.c */
574 
575 extern int vt_ioctl(struct tty_struct *tty, struct file *file,
576 		    unsigned int cmd, unsigned long arg);
577 
578 extern long vt_compat_ioctl(struct tty_struct *tty, struct file * file,
579 		     unsigned int cmd, unsigned long arg);
580 
581 /* tty_mutex.c */
582 /* functions for preparation of BKL removal */
583 extern void __lockfunc tty_lock(void) __acquires(tty_lock);
584 extern void __lockfunc tty_unlock(void) __releases(tty_lock);
585 extern struct task_struct *__big_tty_mutex_owner;
586 #define tty_locked()		(current == __big_tty_mutex_owner)
587 
588 /*
589  * wait_event_interruptible_tty -- wait for a condition with the tty lock held
590  *
591  * The condition we are waiting for might take a long time to
592  * become true, or might depend on another thread taking the
593  * BTM. In either case, we need to drop the BTM to guarantee
594  * forward progress. This is a leftover from the conversion
595  * from the BKL and should eventually get removed as the BTM
596  * falls out of use.
597  *
598  * Do not use in new code.
599  */
600 #define wait_event_interruptible_tty(wq, condition)			\
601 ({									\
602 	int __ret = 0;							\
603 	if (!(condition)) {						\
604 		__wait_event_interruptible_tty(wq, condition, __ret);	\
605 	}								\
606 	__ret;								\
607 })
608 
609 #define __wait_event_interruptible_tty(wq, condition, ret)		\
610 do {									\
611 	DEFINE_WAIT(__wait);						\
612 									\
613 	for (;;) {							\
614 		prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE);	\
615 		if (condition)						\
616 			break;						\
617 		if (!signal_pending(current)) {				\
618 			tty_unlock();					\
619 			schedule();					\
620 			tty_lock();					\
621 			continue;					\
622 		}							\
623 		ret = -ERESTARTSYS;					\
624 		break;							\
625 	}								\
626 	finish_wait(&wq, &__wait);					\
627 } while (0)
628 
629 
630 #endif /* __KERNEL__ */
631 #endif
632