xref: /linux-6.15/include/linux/tty.h (revision facb4edc)
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 
17 #include <asm/system.h>
18 
19 
20 /*
21  * (Note: the *_driver.minor_start values 1, 64, 128, 192 are
22  * hardcoded at present.)
23  */
24 #define NR_UNIX98_PTY_DEFAULT	4096      /* Default maximum for Unix98 ptys */
25 #define NR_UNIX98_PTY_MAX	(1 << MINORBITS) /* Absolute limit */
26 #define NR_LDISCS		30
27 
28 /* line disciplines */
29 #define N_TTY		0
30 #define N_SLIP		1
31 #define N_MOUSE		2
32 #define N_PPP		3
33 #define N_STRIP		4
34 #define N_AX25		5
35 #define N_X25		6	/* X.25 async */
36 #define N_6PACK		7
37 #define N_MASC		8	/* Reserved for Mobitex module <[email protected]> */
38 #define N_R3964		9	/* Reserved for Simatic R3964 module */
39 #define N_PROFIBUS_FDL	10	/* Reserved for Profibus */
40 #define N_IRDA		11	/* Linux IrDa - http://irda.sourceforge.net/ */
41 #define N_SMSBLOCK	12	/* SMS block mode - for talking to GSM data */
42 				/* cards about SMS messages */
43 #define N_HDLC		13	/* synchronous HDLC */
44 #define N_SYNC_PPP	14	/* synchronous PPP */
45 #define N_HCI		15	/* Bluetooth HCI UART */
46 #define N_GIGASET_M101	16	/* Siemens Gigaset M101 serial DECT adapter */
47 #define N_SLCAN		17	/* Serial / USB serial CAN Adaptors */
48 #define N_PPS		18	/* Pulse per Second */
49 #define N_V253		19	/* Codec control over voice modem */
50 #define N_CAIF		20      /* CAIF protocol for talking to modems */
51 #define N_GSM0710	21	/* GSM 0710 Mux */
52 #define N_TI_WL		22	/* for TI's WL BT, FM, GPS combo chips */
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 device *dev;
260 	struct tty_driver *driver;
261 	const struct tty_operations *ops;
262 	int index;
263 
264 	/* Protects ldisc changes: Lock tty not pty */
265 	struct mutex ldisc_mutex;
266 	struct tty_ldisc *ldisc;
267 
268 	struct mutex termios_mutex;
269 	spinlock_t ctrl_lock;
270 	/* Termios values are protected by the termios mutex */
271 	struct ktermios *termios, *termios_locked;
272 	struct termiox *termiox;	/* May be NULL for unsupported */
273 	char name[64];
274 	struct pid *pgrp;		/* Protected by ctrl lock */
275 	struct pid *session;
276 	unsigned long flags;
277 	int count;
278 	struct winsize winsize;		/* termios mutex */
279 	unsigned char stopped:1, hw_stopped:1, flow_stopped:1, packet:1;
280 	unsigned char low_latency:1, warned:1;
281 	unsigned char ctrl_status;	/* ctrl_lock */
282 	unsigned int receive_room;	/* Bytes free for queue */
283 
284 	struct tty_struct *link;
285 	struct fasync_struct *fasync;
286 	struct tty_bufhead buf;		/* Locked internally */
287 	int alt_speed;		/* For magic substitution of 38400 bps */
288 	wait_queue_head_t write_wait;
289 	wait_queue_head_t read_wait;
290 	struct work_struct hangup_work;
291 	void *disc_data;
292 	void *driver_data;
293 	struct list_head tty_files;
294 
295 #define N_TTY_BUF_SIZE 4096
296 
297 	/*
298 	 * The following is data for the N_TTY line discipline.  For
299 	 * historical reasons, this is included in the tty structure.
300 	 * Mostly locked by the BKL.
301 	 */
302 	unsigned int column;
303 	unsigned char lnext:1, erasing:1, raw:1, real_raw:1, icanon:1;
304 	unsigned char closing:1;
305 	unsigned char echo_overrun:1;
306 	unsigned short minimum_to_wake;
307 	unsigned long overrun_time;
308 	int num_overrun;
309 	unsigned long process_char_map[256/(8*sizeof(unsigned long))];
310 	char *read_buf;
311 	int read_head;
312 	int read_tail;
313 	int read_cnt;
314 	unsigned long read_flags[N_TTY_BUF_SIZE/(8*sizeof(unsigned long))];
315 	unsigned char *echo_buf;
316 	unsigned int echo_pos;
317 	unsigned int echo_cnt;
318 	int canon_data;
319 	unsigned long canon_head;
320 	unsigned int canon_column;
321 	struct mutex atomic_read_lock;
322 	struct mutex atomic_write_lock;
323 	struct mutex output_lock;
324 	struct mutex echo_lock;
325 	unsigned char *write_buf;
326 	int write_cnt;
327 	spinlock_t read_lock;
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 };
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_DEBUG 		4	/* Debugging */
356 #define TTY_DO_WRITE_WAKEUP 	5	/* Call write_wakeup after queuing new */
357 #define TTY_PUSH 		6	/* n_tty private */
358 #define TTY_CLOSING 		7	/* ->close() in progress */
359 #define TTY_LDISC 		9	/* Line discipline attached */
360 #define TTY_LDISC_CHANGING 	10	/* Line discipline changing */
361 #define TTY_LDISC_OPEN	 	11	/* Line discipline is open */
362 #define TTY_HW_COOK_OUT 	14	/* Hardware can do output cooking */
363 #define TTY_HW_COOK_IN 		15	/* Hardware can do input cooking */
364 #define TTY_PTY_LOCK 		16	/* pty private */
365 #define TTY_NO_WRITE_SPLIT 	17	/* Preserve write boundaries to driver */
366 #define TTY_HUPPED 		18	/* Post driver->hangup() */
367 #define TTY_FLUSHING		19	/* Flushing to ldisc in progress */
368 #define TTY_FLUSHPENDING	20	/* Queued buffer flush pending */
369 #define TTY_HUPPING 		21	/* ->hangup() in progress */
370 
371 #define TTY_WRITE_FLUSH(tty) tty_write_flush((tty))
372 
373 extern void tty_write_flush(struct tty_struct *);
374 
375 extern struct ktermios tty_std_termios;
376 
377 extern void console_init(void);
378 extern int vcs_init(void);
379 
380 extern struct class *tty_class;
381 
382 /**
383  *	tty_kref_get		-	get a tty reference
384  *	@tty: tty device
385  *
386  *	Return a new reference to a tty object. The caller must hold
387  *	sufficient locks/counts to ensure that their existing reference cannot
388  *	go away
389  */
390 
391 static inline struct tty_struct *tty_kref_get(struct tty_struct *tty)
392 {
393 	if (tty)
394 		kref_get(&tty->kref);
395 	return tty;
396 }
397 extern void tty_kref_put(struct tty_struct *tty);
398 
399 extern int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
400 			      const char *routine);
401 extern char *tty_name(struct tty_struct *tty, char *buf);
402 extern void tty_wait_until_sent(struct tty_struct *tty, long timeout);
403 extern int tty_check_change(struct tty_struct *tty);
404 extern void stop_tty(struct tty_struct *tty);
405 extern void start_tty(struct tty_struct *tty);
406 extern int tty_register_driver(struct tty_driver *driver);
407 extern int tty_unregister_driver(struct tty_driver *driver);
408 extern struct device *tty_register_device(struct tty_driver *driver,
409 					  unsigned index, struct device *dev);
410 extern void tty_unregister_device(struct tty_driver *driver, unsigned index);
411 extern int tty_read_raw_data(struct tty_struct *tty, unsigned char *bufp,
412 			     int buflen);
413 extern void tty_write_message(struct tty_struct *tty, char *msg);
414 extern int tty_put_char(struct tty_struct *tty, unsigned char c);
415 extern int tty_chars_in_buffer(struct tty_struct *tty);
416 extern int tty_write_room(struct tty_struct *tty);
417 extern void tty_driver_flush_buffer(struct tty_struct *tty);
418 extern void tty_throttle(struct tty_struct *tty);
419 extern void tty_unthrottle(struct tty_struct *tty);
420 extern int tty_do_resize(struct tty_struct *tty, struct winsize *ws);
421 extern void tty_shutdown(struct tty_struct *tty);
422 extern void tty_free_termios(struct tty_struct *tty);
423 extern int is_current_pgrp_orphaned(void);
424 extern struct pid *tty_get_pgrp(struct tty_struct *tty);
425 extern int is_ignored(int sig);
426 extern int tty_signal(int sig, struct tty_struct *tty);
427 extern void tty_hangup(struct tty_struct *tty);
428 extern void tty_vhangup(struct tty_struct *tty);
429 extern void tty_vhangup_locked(struct tty_struct *tty);
430 extern void tty_vhangup_self(void);
431 extern void tty_unhangup(struct file *filp);
432 extern int tty_hung_up_p(struct file *filp);
433 extern void do_SAK(struct tty_struct *tty);
434 extern void __do_SAK(struct tty_struct *tty);
435 extern void disassociate_ctty(int priv);
436 extern void no_tty(void);
437 extern void tty_flip_buffer_push(struct tty_struct *tty);
438 extern void tty_flush_to_ldisc(struct tty_struct *tty);
439 extern void tty_buffer_free_all(struct tty_struct *tty);
440 extern void tty_buffer_flush(struct tty_struct *tty);
441 extern void tty_buffer_init(struct tty_struct *tty);
442 extern speed_t tty_get_baud_rate(struct tty_struct *tty);
443 extern speed_t tty_termios_baud_rate(struct ktermios *termios);
444 extern speed_t tty_termios_input_baud_rate(struct ktermios *termios);
445 extern void tty_termios_encode_baud_rate(struct ktermios *termios,
446 						speed_t ibaud, speed_t obaud);
447 extern void tty_encode_baud_rate(struct tty_struct *tty,
448 						speed_t ibaud, speed_t obaud);
449 extern void tty_termios_copy_hw(struct ktermios *new, struct ktermios *old);
450 extern int tty_termios_hw_change(struct ktermios *a, struct ktermios *b);
451 
452 extern struct tty_ldisc *tty_ldisc_ref(struct tty_struct *);
453 extern void tty_ldisc_deref(struct tty_ldisc *);
454 extern struct tty_ldisc *tty_ldisc_ref_wait(struct tty_struct *);
455 extern void tty_ldisc_hangup(struct tty_struct *tty);
456 extern const struct file_operations tty_ldiscs_proc_fops;
457 
458 extern void tty_wakeup(struct tty_struct *tty);
459 extern void tty_ldisc_flush(struct tty_struct *tty);
460 
461 extern long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
462 extern int tty_mode_ioctl(struct tty_struct *tty, struct file *file,
463 			unsigned int cmd, unsigned long arg);
464 extern int tty_perform_flush(struct tty_struct *tty, unsigned long arg);
465 extern dev_t tty_devnum(struct tty_struct *tty);
466 extern void proc_clear_tty(struct task_struct *p);
467 extern struct tty_struct *get_current_tty(void);
468 extern void tty_default_fops(struct file_operations *fops);
469 extern struct tty_struct *alloc_tty_struct(void);
470 extern int tty_add_file(struct tty_struct *tty, struct file *file);
471 extern void free_tty_struct(struct tty_struct *tty);
472 extern void initialize_tty_struct(struct tty_struct *tty,
473 		struct tty_driver *driver, int idx);
474 extern struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx,
475 								int first_ok);
476 extern int tty_release(struct inode *inode, struct file *filp);
477 extern int tty_init_termios(struct tty_struct *tty);
478 
479 extern struct tty_struct *tty_pair_get_tty(struct tty_struct *tty);
480 extern struct tty_struct *tty_pair_get_pty(struct tty_struct *tty);
481 
482 extern struct mutex tty_mutex;
483 extern spinlock_t tty_files_lock;
484 
485 extern void tty_write_unlock(struct tty_struct *tty);
486 extern int tty_write_lock(struct tty_struct *tty, int ndelay);
487 #define tty_is_writelocked(tty)  (mutex_is_locked(&tty->atomic_write_lock))
488 
489 extern void tty_port_init(struct tty_port *port);
490 extern int tty_port_alloc_xmit_buf(struct tty_port *port);
491 extern void tty_port_free_xmit_buf(struct tty_port *port);
492 extern void tty_port_put(struct tty_port *port);
493 
494 static inline struct tty_port *tty_port_get(struct tty_port *port)
495 {
496 	if (port)
497 		kref_get(&port->kref);
498 	return port;
499 }
500 
501 extern struct tty_struct *tty_port_tty_get(struct tty_port *port);
502 extern void tty_port_tty_set(struct tty_port *port, struct tty_struct *tty);
503 extern int tty_port_carrier_raised(struct tty_port *port);
504 extern void tty_port_raise_dtr_rts(struct tty_port *port);
505 extern void tty_port_lower_dtr_rts(struct tty_port *port);
506 extern void tty_port_hangup(struct tty_port *port);
507 extern int tty_port_block_til_ready(struct tty_port *port,
508 				struct tty_struct *tty, struct file *filp);
509 extern int tty_port_close_start(struct tty_port *port,
510 				struct tty_struct *tty, struct file *filp);
511 extern void tty_port_close_end(struct tty_port *port, struct tty_struct *tty);
512 extern void tty_port_close(struct tty_port *port,
513 				struct tty_struct *tty, struct file *filp);
514 extern int tty_port_open(struct tty_port *port,
515 				struct tty_struct *tty, struct file *filp);
516 static inline int tty_port_users(struct tty_port *port)
517 {
518 	return port->count + port->blocked_open;
519 }
520 
521 extern int tty_register_ldisc(int disc, struct tty_ldisc_ops *new_ldisc);
522 extern int tty_unregister_ldisc(int disc);
523 extern int tty_set_ldisc(struct tty_struct *tty, int ldisc);
524 extern int tty_ldisc_setup(struct tty_struct *tty, struct tty_struct *o_tty);
525 extern void tty_ldisc_release(struct tty_struct *tty, struct tty_struct *o_tty);
526 extern void tty_ldisc_init(struct tty_struct *tty);
527 extern void tty_ldisc_begin(void);
528 /* This last one is just for the tty layer internals and shouldn't be used elsewhere */
529 extern void tty_ldisc_enable(struct tty_struct *tty);
530 
531 
532 /* n_tty.c */
533 extern struct tty_ldisc_ops tty_ldisc_N_TTY;
534 extern void n_tty_inherit_ops(struct tty_ldisc_ops *ops);
535 
536 /* tty_audit.c */
537 #ifdef CONFIG_AUDIT
538 extern void tty_audit_add_data(struct tty_struct *tty, unsigned char *data,
539 			       size_t size);
540 extern void tty_audit_exit(void);
541 extern void tty_audit_fork(struct signal_struct *sig);
542 extern void tty_audit_tiocsti(struct tty_struct *tty, char ch);
543 extern void tty_audit_push(struct tty_struct *tty);
544 extern int tty_audit_push_task(struct task_struct *tsk,
545 			       uid_t loginuid, u32 sessionid);
546 #else
547 static inline void tty_audit_add_data(struct tty_struct *tty,
548 				      unsigned char *data, size_t size)
549 {
550 }
551 static inline void tty_audit_tiocsti(struct tty_struct *tty, char ch)
552 {
553 }
554 static inline void tty_audit_exit(void)
555 {
556 }
557 static inline void tty_audit_fork(struct signal_struct *sig)
558 {
559 }
560 static inline void tty_audit_push(struct tty_struct *tty)
561 {
562 }
563 static inline int tty_audit_push_task(struct task_struct *tsk,
564 				      uid_t loginuid, u32 sessionid)
565 {
566 	return 0;
567 }
568 #endif
569 
570 /* tty_io.c */
571 extern int __init tty_init(void);
572 
573 /* tty_ioctl.c */
574 extern int n_tty_ioctl_helper(struct tty_struct *tty, struct file *file,
575 		       unsigned int cmd, unsigned long arg);
576 
577 /* serial.c */
578 
579 extern void serial_console_init(void);
580 
581 /* pcxx.c */
582 
583 extern int pcxe_open(struct tty_struct *tty, struct file *filp);
584 
585 /* vt.c */
586 
587 extern int vt_ioctl(struct tty_struct *tty, struct file *file,
588 		    unsigned int cmd, unsigned long arg);
589 
590 extern long vt_compat_ioctl(struct tty_struct *tty, struct file * file,
591 		     unsigned int cmd, unsigned long arg);
592 
593 /* tty_mutex.c */
594 /* functions for preparation of BKL removal */
595 extern void __lockfunc tty_lock(void) __acquires(tty_lock);
596 extern void __lockfunc tty_unlock(void) __releases(tty_lock);
597 extern struct task_struct *__big_tty_mutex_owner;
598 #define tty_locked()		(current == __big_tty_mutex_owner)
599 
600 /*
601  * wait_event_interruptible_tty -- wait for a condition with the tty lock held
602  *
603  * The condition we are waiting for might take a long time to
604  * become true, or might depend on another thread taking the
605  * BTM. In either case, we need to drop the BTM to guarantee
606  * forward progress. This is a leftover from the conversion
607  * from the BKL and should eventually get removed as the BTM
608  * falls out of use.
609  *
610  * Do not use in new code.
611  */
612 #define wait_event_interruptible_tty(wq, condition)			\
613 ({									\
614 	int __ret = 0;							\
615 	if (!(condition)) {						\
616 		__wait_event_interruptible_tty(wq, condition, __ret);	\
617 	}								\
618 	__ret;								\
619 })
620 
621 #define __wait_event_interruptible_tty(wq, condition, ret)		\
622 do {									\
623 	DEFINE_WAIT(__wait);						\
624 									\
625 	for (;;) {							\
626 		prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE);	\
627 		if (condition)						\
628 			break;						\
629 		if (!signal_pending(current)) {				\
630 			tty_unlock();					\
631 			schedule();					\
632 			tty_lock();					\
633 			continue;					\
634 		}							\
635 		ret = -ERESTARTSYS;					\
636 		break;							\
637 	}								\
638 	finish_wait(&wq, &__wait);					\
639 } while (0)
640 
641 
642 #endif /* __KERNEL__ */
643 #endif
644