xref: /linux-6.15/include/linux/tty.h (revision 4413e16d)
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 #define NR_LDISCS		30
9 
10 /* line disciplines */
11 #define N_TTY		0
12 #define N_SLIP		1
13 #define N_MOUSE		2
14 #define N_PPP		3
15 #define N_STRIP		4
16 #define N_AX25		5
17 #define N_X25		6	/* X.25 async */
18 #define N_6PACK		7
19 #define N_MASC		8	/* Reserved for Mobitex module <[email protected]> */
20 #define N_R3964		9	/* Reserved for Simatic R3964 module */
21 #define N_PROFIBUS_FDL	10	/* Reserved for Profibus */
22 #define N_IRDA		11	/* Linux IrDa - http://irda.sourceforge.net/ */
23 #define N_SMSBLOCK	12	/* SMS block mode - for talking to GSM data */
24 				/* cards about SMS messages */
25 #define N_HDLC		13	/* synchronous HDLC */
26 #define N_SYNC_PPP	14	/* synchronous PPP */
27 #define N_HCI		15	/* Bluetooth HCI UART */
28 #define N_GIGASET_M101	16	/* Siemens Gigaset M101 serial DECT adapter */
29 #define N_SLCAN		17	/* Serial / USB serial CAN Adaptors */
30 #define N_PPS		18	/* Pulse per Second */
31 #define N_V253		19	/* Codec control over voice modem */
32 #define N_CAIF		20      /* CAIF protocol for talking to modems */
33 #define N_GSM0710	21	/* GSM 0710 Mux */
34 #define N_TI_WL		22	/* for TI's WL BT, FM, GPS combo chips */
35 #define N_TRACESINK	23	/* Trace data routing for MIPI P1149.7 */
36 #define N_TRACEROUTER	24	/* Trace data routing for MIPI P1149.7 */
37 
38 #ifdef __KERNEL__
39 #include <linux/fs.h>
40 #include <linux/major.h>
41 #include <linux/termios.h>
42 #include <linux/workqueue.h>
43 #include <linux/tty_driver.h>
44 #include <linux/tty_ldisc.h>
45 #include <linux/mutex.h>
46 #include <linux/tty_flags.h>
47 
48 
49 
50 /*
51  * (Note: the *_driver.minor_start values 1, 64, 128, 192 are
52  * hardcoded at present.)
53  */
54 #define NR_UNIX98_PTY_DEFAULT	4096      /* Default maximum for Unix98 ptys */
55 #define NR_UNIX98_PTY_RESERVE	1024	  /* Default reserve for main devpts */
56 #define NR_UNIX98_PTY_MAX	(1 << MINORBITS) /* Absolute limit */
57 
58 /*
59  * This character is the same as _POSIX_VDISABLE: it cannot be used as
60  * a c_cc[] character, but indicates that a particular special character
61  * isn't in use (eg VINTR has no character etc)
62  */
63 #define __DISABLED_CHAR '\0'
64 
65 struct tty_buffer {
66 	struct tty_buffer *next;
67 	char *char_buf_ptr;
68 	unsigned char *flag_buf_ptr;
69 	int used;
70 	int size;
71 	int commit;
72 	int read;
73 	/* Data points here */
74 	unsigned long data[0];
75 };
76 
77 /*
78  * We default to dicing tty buffer allocations to this many characters
79  * in order to avoid multiple page allocations. We know the size of
80  * tty_buffer itself but it must also be taken into account that the
81  * the buffer is 256 byte aligned. See tty_buffer_find for the allocation
82  * logic this must match
83  */
84 
85 #define TTY_BUFFER_PAGE	(((PAGE_SIZE - sizeof(struct tty_buffer)) / 2) & ~0xFF)
86 
87 
88 struct tty_bufhead {
89 	struct work_struct work;
90 	spinlock_t lock;
91 	struct tty_buffer *head;	/* Queue head */
92 	struct tty_buffer *tail;	/* Active buffer */
93 	struct tty_buffer *free;	/* Free queue head */
94 	int memory_used;		/* Buffer space used excluding
95 								free queue */
96 };
97 /*
98  * When a break, frame error, or parity error happens, these codes are
99  * stuffed into the flags buffer.
100  */
101 #define TTY_NORMAL	0
102 #define TTY_BREAK	1
103 #define TTY_FRAME	2
104 #define TTY_PARITY	3
105 #define TTY_OVERRUN	4
106 
107 #define INTR_CHAR(tty) ((tty)->termios.c_cc[VINTR])
108 #define QUIT_CHAR(tty) ((tty)->termios.c_cc[VQUIT])
109 #define ERASE_CHAR(tty) ((tty)->termios.c_cc[VERASE])
110 #define KILL_CHAR(tty) ((tty)->termios.c_cc[VKILL])
111 #define EOF_CHAR(tty) ((tty)->termios.c_cc[VEOF])
112 #define TIME_CHAR(tty) ((tty)->termios.c_cc[VTIME])
113 #define MIN_CHAR(tty) ((tty)->termios.c_cc[VMIN])
114 #define SWTC_CHAR(tty) ((tty)->termios.c_cc[VSWTC])
115 #define START_CHAR(tty) ((tty)->termios.c_cc[VSTART])
116 #define STOP_CHAR(tty) ((tty)->termios.c_cc[VSTOP])
117 #define SUSP_CHAR(tty) ((tty)->termios.c_cc[VSUSP])
118 #define EOL_CHAR(tty) ((tty)->termios.c_cc[VEOL])
119 #define REPRINT_CHAR(tty) ((tty)->termios.c_cc[VREPRINT])
120 #define DISCARD_CHAR(tty) ((tty)->termios.c_cc[VDISCARD])
121 #define WERASE_CHAR(tty) ((tty)->termios.c_cc[VWERASE])
122 #define LNEXT_CHAR(tty)	((tty)->termios.c_cc[VLNEXT])
123 #define EOL2_CHAR(tty) ((tty)->termios.c_cc[VEOL2])
124 
125 #define _I_FLAG(tty, f)	((tty)->termios.c_iflag & (f))
126 #define _O_FLAG(tty, f)	((tty)->termios.c_oflag & (f))
127 #define _C_FLAG(tty, f)	((tty)->termios.c_cflag & (f))
128 #define _L_FLAG(tty, f)	((tty)->termios.c_lflag & (f))
129 
130 #define I_IGNBRK(tty)	_I_FLAG((tty), IGNBRK)
131 #define I_BRKINT(tty)	_I_FLAG((tty), BRKINT)
132 #define I_IGNPAR(tty)	_I_FLAG((tty), IGNPAR)
133 #define I_PARMRK(tty)	_I_FLAG((tty), PARMRK)
134 #define I_INPCK(tty)	_I_FLAG((tty), INPCK)
135 #define I_ISTRIP(tty)	_I_FLAG((tty), ISTRIP)
136 #define I_INLCR(tty)	_I_FLAG((tty), INLCR)
137 #define I_IGNCR(tty)	_I_FLAG((tty), IGNCR)
138 #define I_ICRNL(tty)	_I_FLAG((tty), ICRNL)
139 #define I_IUCLC(tty)	_I_FLAG((tty), IUCLC)
140 #define I_IXON(tty)	_I_FLAG((tty), IXON)
141 #define I_IXANY(tty)	_I_FLAG((tty), IXANY)
142 #define I_IXOFF(tty)	_I_FLAG((tty), IXOFF)
143 #define I_IMAXBEL(tty)	_I_FLAG((tty), IMAXBEL)
144 #define I_IUTF8(tty)	_I_FLAG((tty), IUTF8)
145 
146 #define O_OPOST(tty)	_O_FLAG((tty), OPOST)
147 #define O_OLCUC(tty)	_O_FLAG((tty), OLCUC)
148 #define O_ONLCR(tty)	_O_FLAG((tty), ONLCR)
149 #define O_OCRNL(tty)	_O_FLAG((tty), OCRNL)
150 #define O_ONOCR(tty)	_O_FLAG((tty), ONOCR)
151 #define O_ONLRET(tty)	_O_FLAG((tty), ONLRET)
152 #define O_OFILL(tty)	_O_FLAG((tty), OFILL)
153 #define O_OFDEL(tty)	_O_FLAG((tty), OFDEL)
154 #define O_NLDLY(tty)	_O_FLAG((tty), NLDLY)
155 #define O_CRDLY(tty)	_O_FLAG((tty), CRDLY)
156 #define O_TABDLY(tty)	_O_FLAG((tty), TABDLY)
157 #define O_BSDLY(tty)	_O_FLAG((tty), BSDLY)
158 #define O_VTDLY(tty)	_O_FLAG((tty), VTDLY)
159 #define O_FFDLY(tty)	_O_FLAG((tty), FFDLY)
160 
161 #define C_BAUD(tty)	_C_FLAG((tty), CBAUD)
162 #define C_CSIZE(tty)	_C_FLAG((tty), CSIZE)
163 #define C_CSTOPB(tty)	_C_FLAG((tty), CSTOPB)
164 #define C_CREAD(tty)	_C_FLAG((tty), CREAD)
165 #define C_PARENB(tty)	_C_FLAG((tty), PARENB)
166 #define C_PARODD(tty)	_C_FLAG((tty), PARODD)
167 #define C_HUPCL(tty)	_C_FLAG((tty), HUPCL)
168 #define C_CLOCAL(tty)	_C_FLAG((tty), CLOCAL)
169 #define C_CIBAUD(tty)	_C_FLAG((tty), CIBAUD)
170 #define C_CRTSCTS(tty)	_C_FLAG((tty), CRTSCTS)
171 
172 #define L_ISIG(tty)	_L_FLAG((tty), ISIG)
173 #define L_ICANON(tty)	_L_FLAG((tty), ICANON)
174 #define L_XCASE(tty)	_L_FLAG((tty), XCASE)
175 #define L_ECHO(tty)	_L_FLAG((tty), ECHO)
176 #define L_ECHOE(tty)	_L_FLAG((tty), ECHOE)
177 #define L_ECHOK(tty)	_L_FLAG((tty), ECHOK)
178 #define L_ECHONL(tty)	_L_FLAG((tty), ECHONL)
179 #define L_NOFLSH(tty)	_L_FLAG((tty), NOFLSH)
180 #define L_TOSTOP(tty)	_L_FLAG((tty), TOSTOP)
181 #define L_ECHOCTL(tty)	_L_FLAG((tty), ECHOCTL)
182 #define L_ECHOPRT(tty)	_L_FLAG((tty), ECHOPRT)
183 #define L_ECHOKE(tty)	_L_FLAG((tty), ECHOKE)
184 #define L_FLUSHO(tty)	_L_FLAG((tty), FLUSHO)
185 #define L_PENDIN(tty)	_L_FLAG((tty), PENDIN)
186 #define L_IEXTEN(tty)	_L_FLAG((tty), IEXTEN)
187 #define L_EXTPROC(tty)	_L_FLAG((tty), EXTPROC)
188 
189 struct device;
190 struct signal_struct;
191 
192 /*
193  * Port level information. Each device keeps its own port level information
194  * so provide a common structure for those ports wanting to use common support
195  * routines.
196  *
197  * The tty port has a different lifetime to the tty so must be kept apart.
198  * In addition be careful as tty -> port mappings are valid for the life
199  * of the tty object but in many cases port -> tty mappings are valid only
200  * until a hangup so don't use the wrong path.
201  */
202 
203 struct tty_port;
204 
205 struct tty_port_operations {
206 	/* Return 1 if the carrier is raised */
207 	int (*carrier_raised)(struct tty_port *port);
208 	/* Control the DTR line */
209 	void (*dtr_rts)(struct tty_port *port, int raise);
210 	/* Called when the last close completes or a hangup finishes
211 	   IFF the port was initialized. Do not use to free resources. Called
212 	   under the port mutex to serialize against activate/shutdowns */
213 	void (*shutdown)(struct tty_port *port);
214 	void (*drop)(struct tty_port *port);
215 	/* Called under the port mutex from tty_port_open, serialized using
216 	   the port mutex */
217         /* FIXME: long term getting the tty argument *out* of this would be
218            good for consoles */
219 	int (*activate)(struct tty_port *port, struct tty_struct *tty);
220 	/* Called on the final put of a port */
221 	void (*destruct)(struct tty_port *port);
222 };
223 
224 struct tty_port {
225 	struct tty_struct	*tty;		/* Back pointer */
226 	const struct tty_port_operations *ops;	/* Port operations */
227 	spinlock_t		lock;		/* Lock protecting tty field */
228 	int			blocked_open;	/* Waiting to open */
229 	int			count;		/* Usage count */
230 	wait_queue_head_t	open_wait;	/* Open waiters */
231 	wait_queue_head_t	close_wait;	/* Close waiters */
232 	wait_queue_head_t	delta_msr_wait;	/* Modem status change */
233 	unsigned long		flags;		/* TTY flags ASY_*/
234 	unsigned char		console:1;	/* port is a console */
235 	struct mutex		mutex;		/* Locking */
236 	struct mutex		buf_mutex;	/* Buffer alloc lock */
237 	unsigned char		*xmit_buf;	/* Optional buffer */
238 	unsigned int		close_delay;	/* Close port delay */
239 	unsigned int		closing_wait;	/* Delay for output */
240 	int			drain_delay;	/* Set to zero if no pure time
241 						   based drain is needed else
242 						   set to size of fifo */
243 	struct kref		kref;		/* Ref counter */
244 };
245 
246 /*
247  * Where all of the state associated with a tty is kept while the tty
248  * is open.  Since the termios state should be kept even if the tty
249  * has been closed --- for things like the baud rate, etc --- it is
250  * not stored here, but rather a pointer to the real state is stored
251  * here.  Possible the winsize structure should have the same
252  * treatment, but (1) the default 80x24 is usually right and (2) it's
253  * most often used by a windowing system, which will set the correct
254  * size each time the window is created or resized anyway.
255  * 						- TYT, 9/14/92
256  */
257 
258 struct tty_operations;
259 
260 struct tty_struct {
261 	int	magic;
262 	struct kref kref;
263 	struct device *dev;
264 	struct tty_driver *driver;
265 	const struct tty_operations *ops;
266 	int index;
267 
268 	/* Protects ldisc changes: Lock tty not pty */
269 	struct mutex ldisc_mutex;
270 	struct tty_ldisc *ldisc;
271 
272 	struct mutex legacy_mutex;
273 	struct mutex termios_mutex;
274 	spinlock_t ctrl_lock;
275 	/* Termios values are protected by the termios mutex */
276 	struct ktermios termios, termios_locked;
277 	struct termiox *termiox;	/* May be NULL for unsupported */
278 	char name[64];
279 	struct pid *pgrp;		/* Protected by ctrl lock */
280 	struct pid *session;
281 	unsigned long flags;
282 	int count;
283 	struct winsize winsize;		/* termios mutex */
284 	unsigned char stopped:1, hw_stopped:1, flow_stopped:1, packet:1;
285 	unsigned char low_latency:1, warned:1;
286 	unsigned char ctrl_status;	/* ctrl_lock */
287 	unsigned int receive_room;	/* Bytes free for queue */
288 
289 	struct tty_struct *link;
290 	struct fasync_struct *fasync;
291 	struct tty_bufhead buf;		/* Locked internally */
292 	int alt_speed;		/* For magic substitution of 38400 bps */
293 	wait_queue_head_t write_wait;
294 	wait_queue_head_t read_wait;
295 	struct work_struct hangup_work;
296 	void *disc_data;
297 	void *driver_data;
298 	struct list_head tty_files;
299 
300 #define N_TTY_BUF_SIZE 4096
301 
302 	/*
303 	 * The following is data for the N_TTY line discipline.  For
304 	 * historical reasons, this is included in the tty structure.
305 	 * Mostly locked by the BKL.
306 	 */
307 	unsigned int column;
308 	unsigned char lnext:1, erasing:1, raw:1, real_raw:1, icanon:1;
309 	unsigned char closing:1;
310 	unsigned char echo_overrun:1;
311 	unsigned short minimum_to_wake;
312 	unsigned long overrun_time;
313 	int num_overrun;
314 	unsigned long process_char_map[256/(8*sizeof(unsigned long))];
315 	char *read_buf;
316 	int read_head;
317 	int read_tail;
318 	int read_cnt;
319 	unsigned long read_flags[N_TTY_BUF_SIZE/(8*sizeof(unsigned long))];
320 	unsigned char *echo_buf;
321 	unsigned int echo_pos;
322 	unsigned int echo_cnt;
323 	int canon_data;
324 	unsigned long canon_head;
325 	unsigned int canon_column;
326 	struct mutex atomic_read_lock;
327 	struct mutex atomic_write_lock;
328 	struct mutex output_lock;
329 	struct mutex echo_lock;
330 	unsigned char *write_buf;
331 	int write_cnt;
332 	spinlock_t read_lock;
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_DEBUG 		4	/* Debugging */
361 #define TTY_DO_WRITE_WAKEUP 	5	/* Call write_wakeup after queuing new */
362 #define TTY_PUSH 		6	/* n_tty private */
363 #define TTY_CLOSING 		7	/* ->close() in progress */
364 #define TTY_LDISC 		9	/* Line discipline attached */
365 #define TTY_LDISC_CHANGING 	10	/* Line discipline changing */
366 #define TTY_LDISC_OPEN	 	11	/* Line discipline is open */
367 #define TTY_HW_COOK_OUT 	14	/* Hardware can do output cooking */
368 #define TTY_HW_COOK_IN 		15	/* Hardware can do input cooking */
369 #define TTY_PTY_LOCK 		16	/* pty private */
370 #define TTY_NO_WRITE_SPLIT 	17	/* Preserve write boundaries to driver */
371 #define TTY_HUPPED 		18	/* Post driver->hangup() */
372 #define TTY_FLUSHING		19	/* Flushing to ldisc in progress */
373 #define TTY_FLUSHPENDING	20	/* Queued buffer flush pending */
374 #define TTY_HUPPING 		21	/* ->hangup() in progress */
375 
376 #define TTY_WRITE_FLUSH(tty) tty_write_flush((tty))
377 
378 extern void tty_write_flush(struct tty_struct *);
379 
380 extern struct ktermios tty_std_termios;
381 
382 extern void console_init(void);
383 extern int vcs_init(void);
384 
385 extern struct class *tty_class;
386 
387 /**
388  *	tty_kref_get		-	get a tty reference
389  *	@tty: tty device
390  *
391  *	Return a new reference to a tty object. The caller must hold
392  *	sufficient locks/counts to ensure that their existing reference cannot
393  *	go away
394  */
395 
396 static inline struct tty_struct *tty_kref_get(struct tty_struct *tty)
397 {
398 	if (tty)
399 		kref_get(&tty->kref);
400 	return tty;
401 }
402 extern void tty_kref_put(struct tty_struct *tty);
403 
404 extern int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
405 			      const char *routine);
406 extern char *tty_name(struct tty_struct *tty, char *buf);
407 extern void tty_wait_until_sent(struct tty_struct *tty, long timeout);
408 extern int tty_check_change(struct tty_struct *tty);
409 extern void stop_tty(struct tty_struct *tty);
410 extern void start_tty(struct tty_struct *tty);
411 extern int tty_register_driver(struct tty_driver *driver);
412 extern int tty_unregister_driver(struct tty_driver *driver);
413 extern struct device *tty_register_device(struct tty_driver *driver,
414 					  unsigned index, struct device *dev);
415 extern struct device *tty_register_device_attr(struct tty_driver *driver,
416 				unsigned index, struct device *device,
417 				void *drvdata,
418 				const struct attribute_group **attr_grp);
419 extern void tty_unregister_device(struct tty_driver *driver, unsigned index);
420 extern int tty_read_raw_data(struct tty_struct *tty, unsigned char *bufp,
421 			     int buflen);
422 extern void tty_write_message(struct tty_struct *tty, char *msg);
423 extern int tty_put_char(struct tty_struct *tty, unsigned char c);
424 extern int tty_chars_in_buffer(struct tty_struct *tty);
425 extern int tty_write_room(struct tty_struct *tty);
426 extern void tty_driver_flush_buffer(struct tty_struct *tty);
427 extern void tty_throttle(struct tty_struct *tty);
428 extern void tty_unthrottle(struct tty_struct *tty);
429 extern int tty_do_resize(struct tty_struct *tty, struct winsize *ws);
430 extern void tty_driver_remove_tty(struct tty_driver *driver,
431 				  struct tty_struct *tty);
432 extern void tty_free_termios(struct tty_struct *tty);
433 extern int is_current_pgrp_orphaned(void);
434 extern struct pid *tty_get_pgrp(struct tty_struct *tty);
435 extern int is_ignored(int sig);
436 extern int tty_signal(int sig, struct tty_struct *tty);
437 extern void tty_hangup(struct tty_struct *tty);
438 extern void tty_vhangup(struct tty_struct *tty);
439 extern void tty_vhangup_locked(struct tty_struct *tty);
440 extern void tty_vhangup_self(void);
441 extern void tty_unhangup(struct file *filp);
442 extern int tty_hung_up_p(struct file *filp);
443 extern void do_SAK(struct tty_struct *tty);
444 extern void __do_SAK(struct tty_struct *tty);
445 extern void disassociate_ctty(int priv);
446 extern void no_tty(void);
447 extern void tty_flip_buffer_push(struct tty_struct *tty);
448 extern void tty_flush_to_ldisc(struct tty_struct *tty);
449 extern void tty_buffer_free_all(struct tty_struct *tty);
450 extern void tty_buffer_flush(struct tty_struct *tty);
451 extern void tty_buffer_init(struct tty_struct *tty);
452 extern speed_t tty_get_baud_rate(struct tty_struct *tty);
453 extern speed_t tty_termios_baud_rate(struct ktermios *termios);
454 extern speed_t tty_termios_input_baud_rate(struct ktermios *termios);
455 extern void tty_termios_encode_baud_rate(struct ktermios *termios,
456 						speed_t ibaud, speed_t obaud);
457 extern void tty_encode_baud_rate(struct tty_struct *tty,
458 						speed_t ibaud, speed_t obaud);
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 dev_t tty_devnum(struct tty_struct *tty);
477 extern void proc_clear_tty(struct task_struct *p);
478 extern struct tty_struct *get_current_tty(void);
479 extern void tty_default_fops(struct file_operations *fops);
480 extern struct tty_struct *alloc_tty_struct(void);
481 extern int tty_alloc_file(struct file *file);
482 extern void tty_add_file(struct tty_struct *tty, struct file *file);
483 extern void tty_free_file(struct file *file);
484 extern void free_tty_struct(struct tty_struct *tty);
485 extern void initialize_tty_struct(struct tty_struct *tty,
486 		struct tty_driver *driver, int idx);
487 extern void deinitialize_tty_struct(struct tty_struct *tty);
488 extern struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx);
489 extern int tty_release(struct inode *inode, struct file *filp);
490 extern int tty_init_termios(struct tty_struct *tty);
491 extern int tty_standard_install(struct tty_driver *driver,
492 		struct tty_struct *tty);
493 
494 extern struct tty_struct *tty_pair_get_tty(struct tty_struct *tty);
495 extern struct tty_struct *tty_pair_get_pty(struct tty_struct *tty);
496 
497 extern struct mutex tty_mutex;
498 extern spinlock_t tty_files_lock;
499 
500 extern void tty_write_unlock(struct tty_struct *tty);
501 extern int tty_write_lock(struct tty_struct *tty, int ndelay);
502 #define tty_is_writelocked(tty)  (mutex_is_locked(&tty->atomic_write_lock))
503 
504 extern void tty_port_init(struct tty_port *port);
505 extern void tty_port_link_device(struct tty_port *port,
506 		struct tty_driver *driver, unsigned index);
507 extern struct device *tty_port_register_device(struct tty_port *port,
508 		struct tty_driver *driver, unsigned index,
509 		struct device *device);
510 extern struct device *tty_port_register_device_attr(struct tty_port *port,
511 		struct tty_driver *driver, unsigned index,
512 		struct device *device, void *drvdata,
513 		const struct attribute_group **attr_grp);
514 extern int tty_port_alloc_xmit_buf(struct tty_port *port);
515 extern void tty_port_free_xmit_buf(struct tty_port *port);
516 extern void tty_port_put(struct tty_port *port);
517 
518 static inline struct tty_port *tty_port_get(struct tty_port *port)
519 {
520 	if (port)
521 		kref_get(&port->kref);
522 	return port;
523 }
524 
525 /* If the cts flow control is enabled, return true. */
526 static inline bool tty_port_cts_enabled(struct tty_port *port)
527 {
528 	return port->flags & ASYNC_CTS_FLOW;
529 }
530 
531 extern struct tty_struct *tty_port_tty_get(struct tty_port *port);
532 extern void tty_port_tty_set(struct tty_port *port, struct tty_struct *tty);
533 extern int tty_port_carrier_raised(struct tty_port *port);
534 extern void tty_port_raise_dtr_rts(struct tty_port *port);
535 extern void tty_port_lower_dtr_rts(struct tty_port *port);
536 extern void tty_port_hangup(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 /* This last one is just for the tty layer internals and shouldn't be used elsewhere */
562 extern void tty_ldisc_enable(struct tty_struct *tty);
563 
564 
565 /* n_tty.c */
566 extern struct tty_ldisc_ops tty_ldisc_N_TTY;
567 extern void n_tty_inherit_ops(struct tty_ldisc_ops *ops);
568 
569 /* tty_audit.c */
570 #ifdef CONFIG_AUDIT
571 extern void tty_audit_add_data(struct tty_struct *tty, unsigned char *data,
572 			       size_t size);
573 extern void tty_audit_exit(void);
574 extern void tty_audit_fork(struct signal_struct *sig);
575 extern void tty_audit_tiocsti(struct tty_struct *tty, char ch);
576 extern void tty_audit_push(struct tty_struct *tty);
577 extern int tty_audit_push_task(struct task_struct *tsk,
578 			       uid_t loginuid, u32 sessionid);
579 #else
580 static inline void tty_audit_add_data(struct tty_struct *tty,
581 				      unsigned char *data, size_t size)
582 {
583 }
584 static inline void tty_audit_tiocsti(struct tty_struct *tty, char ch)
585 {
586 }
587 static inline void tty_audit_exit(void)
588 {
589 }
590 static inline void tty_audit_fork(struct signal_struct *sig)
591 {
592 }
593 static inline void tty_audit_push(struct tty_struct *tty)
594 {
595 }
596 static inline int tty_audit_push_task(struct task_struct *tsk,
597 				      uid_t loginuid, u32 sessionid)
598 {
599 	return 0;
600 }
601 #endif
602 
603 /* tty_io.c */
604 extern int __init tty_init(void);
605 
606 /* tty_ioctl.c */
607 extern int n_tty_ioctl_helper(struct tty_struct *tty, struct file *file,
608 		       unsigned int cmd, unsigned long arg);
609 extern long n_tty_compat_ioctl_helper(struct tty_struct *tty, struct file *file,
610 		       unsigned int cmd, unsigned long arg);
611 
612 /* serial.c */
613 
614 extern void serial_console_init(void);
615 
616 /* pcxx.c */
617 
618 extern int pcxe_open(struct tty_struct *tty, struct file *filp);
619 
620 /* vt.c */
621 
622 extern int vt_ioctl(struct tty_struct *tty,
623 		    unsigned int cmd, unsigned long arg);
624 
625 extern long vt_compat_ioctl(struct tty_struct *tty,
626 		     unsigned int cmd, unsigned long arg);
627 
628 /* tty_mutex.c */
629 /* functions for preparation of BKL removal */
630 extern void __lockfunc tty_lock(struct tty_struct *tty);
631 extern void __lockfunc tty_unlock(struct tty_struct *tty);
632 extern void __lockfunc tty_lock_pair(struct tty_struct *tty,
633 				struct tty_struct *tty2);
634 extern void __lockfunc tty_unlock_pair(struct tty_struct *tty,
635 				struct tty_struct *tty2);
636 
637 /*
638  * this shall be called only from where BTM is held (like close)
639  *
640  * We need this to ensure nobody waits for us to finish while we are waiting.
641  * Without this we were encountering system stalls.
642  *
643  * This should be indeed removed with BTM removal later.
644  *
645  * Locking: BTM required. Nobody is allowed to hold port->mutex.
646  */
647 static inline void tty_wait_until_sent_from_close(struct tty_struct *tty,
648 		long timeout)
649 {
650 	tty_unlock(tty); /* tty->ops->close holds the BTM, drop it while waiting */
651 	tty_wait_until_sent(tty, timeout);
652 	tty_lock(tty);
653 }
654 
655 /*
656  * wait_event_interruptible_tty -- wait for a condition with the tty lock held
657  *
658  * The condition we are waiting for might take a long time to
659  * become true, or might depend on another thread taking the
660  * BTM. In either case, we need to drop the BTM to guarantee
661  * forward progress. This is a leftover from the conversion
662  * from the BKL and should eventually get removed as the BTM
663  * falls out of use.
664  *
665  * Do not use in new code.
666  */
667 #define wait_event_interruptible_tty(tty, wq, condition)		\
668 ({									\
669 	int __ret = 0;							\
670 	if (!(condition)) {						\
671 		__wait_event_interruptible_tty(tty, wq, condition, __ret);	\
672 	}								\
673 	__ret;								\
674 })
675 
676 #define __wait_event_interruptible_tty(tty, wq, condition, ret)		\
677 do {									\
678 	DEFINE_WAIT(__wait);						\
679 									\
680 	for (;;) {							\
681 		prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE);	\
682 		if (condition)						\
683 			break;						\
684 		if (!signal_pending(current)) {				\
685 			tty_unlock(tty);					\
686 			schedule();					\
687 			tty_lock(tty);					\
688 			continue;					\
689 		}							\
690 		ret = -ERESTARTSYS;					\
691 		break;							\
692 	}								\
693 	finish_wait(&wq, &__wait);					\
694 } while (0)
695 
696 
697 #endif /* __KERNEL__ */
698 #endif
699