1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_TTY_H
3 #define _LINUX_TTY_H
4 
5 #include <linux/fs.h>
6 #include <linux/major.h>
7 #include <linux/termios.h>
8 #include <linux/workqueue.h>
9 #include <linux/tty_buffer.h>
10 #include <linux/tty_driver.h>
11 #include <linux/tty_ldisc.h>
12 #include <linux/tty_port.h>
13 #include <linux/mutex.h>
14 #include <linux/tty_flags.h>
15 #include <uapi/linux/tty.h>
16 #include <linux/rwsem.h>
17 #include <linux/llist.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_RESERVE	1024	  /* Default reserve for main devpts */
26 #define NR_UNIX98_PTY_MAX	(1 << MINORBITS) /* Absolute limit */
27 
28 /*
29  * This character is the same as _POSIX_VDISABLE: it cannot be used as
30  * a c_cc[] character, but indicates that a particular special character
31  * isn't in use (eg VINTR has no character etc)
32  */
33 #define __DISABLED_CHAR '\0'
34 
35 #define INTR_CHAR(tty) ((tty)->termios.c_cc[VINTR])
36 #define QUIT_CHAR(tty) ((tty)->termios.c_cc[VQUIT])
37 #define ERASE_CHAR(tty) ((tty)->termios.c_cc[VERASE])
38 #define KILL_CHAR(tty) ((tty)->termios.c_cc[VKILL])
39 #define EOF_CHAR(tty) ((tty)->termios.c_cc[VEOF])
40 #define TIME_CHAR(tty) ((tty)->termios.c_cc[VTIME])
41 #define MIN_CHAR(tty) ((tty)->termios.c_cc[VMIN])
42 #define SWTC_CHAR(tty) ((tty)->termios.c_cc[VSWTC])
43 #define START_CHAR(tty) ((tty)->termios.c_cc[VSTART])
44 #define STOP_CHAR(tty) ((tty)->termios.c_cc[VSTOP])
45 #define SUSP_CHAR(tty) ((tty)->termios.c_cc[VSUSP])
46 #define EOL_CHAR(tty) ((tty)->termios.c_cc[VEOL])
47 #define REPRINT_CHAR(tty) ((tty)->termios.c_cc[VREPRINT])
48 #define DISCARD_CHAR(tty) ((tty)->termios.c_cc[VDISCARD])
49 #define WERASE_CHAR(tty) ((tty)->termios.c_cc[VWERASE])
50 #define LNEXT_CHAR(tty)	((tty)->termios.c_cc[VLNEXT])
51 #define EOL2_CHAR(tty) ((tty)->termios.c_cc[VEOL2])
52 
53 #define _I_FLAG(tty, f)	((tty)->termios.c_iflag & (f))
54 #define _O_FLAG(tty, f)	((tty)->termios.c_oflag & (f))
55 #define _C_FLAG(tty, f)	((tty)->termios.c_cflag & (f))
56 #define _L_FLAG(tty, f)	((tty)->termios.c_lflag & (f))
57 
58 #define I_IGNBRK(tty)	_I_FLAG((tty), IGNBRK)
59 #define I_BRKINT(tty)	_I_FLAG((tty), BRKINT)
60 #define I_IGNPAR(tty)	_I_FLAG((tty), IGNPAR)
61 #define I_PARMRK(tty)	_I_FLAG((tty), PARMRK)
62 #define I_INPCK(tty)	_I_FLAG((tty), INPCK)
63 #define I_ISTRIP(tty)	_I_FLAG((tty), ISTRIP)
64 #define I_INLCR(tty)	_I_FLAG((tty), INLCR)
65 #define I_IGNCR(tty)	_I_FLAG((tty), IGNCR)
66 #define I_ICRNL(tty)	_I_FLAG((tty), ICRNL)
67 #define I_IUCLC(tty)	_I_FLAG((tty), IUCLC)
68 #define I_IXON(tty)	_I_FLAG((tty), IXON)
69 #define I_IXANY(tty)	_I_FLAG((tty), IXANY)
70 #define I_IXOFF(tty)	_I_FLAG((tty), IXOFF)
71 #define I_IMAXBEL(tty)	_I_FLAG((tty), IMAXBEL)
72 #define I_IUTF8(tty)	_I_FLAG((tty), IUTF8)
73 
74 #define O_OPOST(tty)	_O_FLAG((tty), OPOST)
75 #define O_OLCUC(tty)	_O_FLAG((tty), OLCUC)
76 #define O_ONLCR(tty)	_O_FLAG((tty), ONLCR)
77 #define O_OCRNL(tty)	_O_FLAG((tty), OCRNL)
78 #define O_ONOCR(tty)	_O_FLAG((tty), ONOCR)
79 #define O_ONLRET(tty)	_O_FLAG((tty), ONLRET)
80 #define O_OFILL(tty)	_O_FLAG((tty), OFILL)
81 #define O_OFDEL(tty)	_O_FLAG((tty), OFDEL)
82 #define O_NLDLY(tty)	_O_FLAG((tty), NLDLY)
83 #define O_CRDLY(tty)	_O_FLAG((tty), CRDLY)
84 #define O_TABDLY(tty)	_O_FLAG((tty), TABDLY)
85 #define O_BSDLY(tty)	_O_FLAG((tty), BSDLY)
86 #define O_VTDLY(tty)	_O_FLAG((tty), VTDLY)
87 #define O_FFDLY(tty)	_O_FLAG((tty), FFDLY)
88 
89 #define C_BAUD(tty)	_C_FLAG((tty), CBAUD)
90 #define C_CSIZE(tty)	_C_FLAG((tty), CSIZE)
91 #define C_CSTOPB(tty)	_C_FLAG((tty), CSTOPB)
92 #define C_CREAD(tty)	_C_FLAG((tty), CREAD)
93 #define C_PARENB(tty)	_C_FLAG((tty), PARENB)
94 #define C_PARODD(tty)	_C_FLAG((tty), PARODD)
95 #define C_HUPCL(tty)	_C_FLAG((tty), HUPCL)
96 #define C_CLOCAL(tty)	_C_FLAG((tty), CLOCAL)
97 #define C_CIBAUD(tty)	_C_FLAG((tty), CIBAUD)
98 #define C_CRTSCTS(tty)	_C_FLAG((tty), CRTSCTS)
99 #define C_CMSPAR(tty)	_C_FLAG((tty), CMSPAR)
100 
101 #define L_ISIG(tty)	_L_FLAG((tty), ISIG)
102 #define L_ICANON(tty)	_L_FLAG((tty), ICANON)
103 #define L_XCASE(tty)	_L_FLAG((tty), XCASE)
104 #define L_ECHO(tty)	_L_FLAG((tty), ECHO)
105 #define L_ECHOE(tty)	_L_FLAG((tty), ECHOE)
106 #define L_ECHOK(tty)	_L_FLAG((tty), ECHOK)
107 #define L_ECHONL(tty)	_L_FLAG((tty), ECHONL)
108 #define L_NOFLSH(tty)	_L_FLAG((tty), NOFLSH)
109 #define L_TOSTOP(tty)	_L_FLAG((tty), TOSTOP)
110 #define L_ECHOCTL(tty)	_L_FLAG((tty), ECHOCTL)
111 #define L_ECHOPRT(tty)	_L_FLAG((tty), ECHOPRT)
112 #define L_ECHOKE(tty)	_L_FLAG((tty), ECHOKE)
113 #define L_FLUSHO(tty)	_L_FLAG((tty), FLUSHO)
114 #define L_PENDIN(tty)	_L_FLAG((tty), PENDIN)
115 #define L_IEXTEN(tty)	_L_FLAG((tty), IEXTEN)
116 #define L_EXTPROC(tty)	_L_FLAG((tty), EXTPROC)
117 
118 struct device;
119 struct signal_struct;
120 struct tty_operations;
121 
122 /**
123  * struct tty_struct - state associated with a tty while open
124  *
125  * @flow.lock: lock for flow members
126  * @flow.stopped: tty stopped/started by tty_stop/tty_start
127  * @flow.tco_stopped: tty stopped/started by TCOOFF/TCOON ioctls (it has
128  *		      precedense over @flow.stopped)
129  * @flow.unused: alignment for Alpha, so that no members other than @flow.* are
130  *		 modified by the same 64b word store. The @flow's __aligned is
131  *		 there for the very same reason.
132  * @ctrl.lock: lock for ctrl members
133  * @ctrl.pgrp: process group of this tty (setpgrp(2))
134  * @ctrl.session: session of this tty (setsid(2)). Writes are protected by both
135  *		  @ctrl.lock and legacy mutex, readers must use at least one of
136  *		  them.
137  * @ctrl.pktstatus: packet mode status (bitwise OR of TIOCPKT_* constants)
138  * @ctrl.packet: packet mode enabled
139  *
140  * All of the state associated with a tty while the tty is open. Persistent
141  * storage for tty devices is referenced here as @port in struct tty_port.
142  */
143 struct tty_struct {
144 	int	magic;
145 	struct kref kref;
146 	struct device *dev;	/* class device or NULL (e.g. ptys, serdev) */
147 	struct tty_driver *driver;
148 	const struct tty_operations *ops;
149 	int index;
150 
151 	/* Protects ldisc changes: Lock tty not pty */
152 	struct ld_semaphore ldisc_sem;
153 	struct tty_ldisc *ldisc;
154 
155 	struct mutex atomic_write_lock;
156 	struct mutex legacy_mutex;
157 	struct mutex throttle_mutex;
158 	struct rw_semaphore termios_rwsem;
159 	struct mutex winsize_mutex;
160 	/* Termios values are protected by the termios rwsem */
161 	struct ktermios termios, termios_locked;
162 	char name[64];
163 	unsigned long flags;
164 	int count;
165 	struct winsize winsize;		/* winsize_mutex */
166 
167 	struct {
168 		spinlock_t lock;
169 		bool stopped;
170 		bool tco_stopped;
171 		unsigned long unused[0];
172 	} __aligned(sizeof(unsigned long)) flow;
173 
174 	struct {
175 		spinlock_t lock;
176 		struct pid *pgrp;
177 		struct pid *session;
178 		unsigned char pktstatus;
179 		bool packet;
180 		unsigned long unused[0];
181 	} __aligned(sizeof(unsigned long)) ctrl;
182 
183 	int hw_stopped;
184 	unsigned int receive_room;	/* Bytes free for queue */
185 	int flow_change;
186 
187 	struct tty_struct *link;
188 	struct fasync_struct *fasync;
189 	wait_queue_head_t write_wait;
190 	wait_queue_head_t read_wait;
191 	struct work_struct hangup_work;
192 	void *disc_data;
193 	void *driver_data;
194 	spinlock_t files_lock;		/* protects tty_files list */
195 	struct list_head tty_files;
196 
197 #define N_TTY_BUF_SIZE 4096
198 
199 	int closing;
200 	unsigned char *write_buf;
201 	int write_cnt;
202 	/* If the tty has a pending do_SAK, queue it here - akpm */
203 	struct work_struct SAK_work;
204 	struct tty_port *port;
205 } __randomize_layout;
206 
207 /* Each of a tty's open files has private_data pointing to tty_file_private */
208 struct tty_file_private {
209 	struct tty_struct *tty;
210 	struct file *file;
211 	struct list_head list;
212 };
213 
214 /* tty magic number */
215 #define TTY_MAGIC		0x5401
216 
217 /*
218  * These bits are used in the flags field of the tty structure.
219  *
220  * So that interrupts won't be able to mess up the queues,
221  * copy_to_cooked must be atomic with respect to itself, as must
222  * tty->write.  Thus, you must use the inline functions set_bit() and
223  * clear_bit() to make things atomic.
224  */
225 #define TTY_THROTTLED 		0	/* Call unthrottle() at threshold min */
226 #define TTY_IO_ERROR 		1	/* Cause an I/O error (may be no ldisc too) */
227 #define TTY_OTHER_CLOSED 	2	/* Other side (if any) has closed */
228 #define TTY_EXCLUSIVE 		3	/* Exclusive open mode */
229 #define TTY_DO_WRITE_WAKEUP 	5	/* Call write_wakeup after queuing new */
230 #define TTY_LDISC_OPEN	 	11	/* Line discipline is open */
231 #define TTY_PTY_LOCK 		16	/* pty private */
232 #define TTY_NO_WRITE_SPLIT 	17	/* Preserve write boundaries to driver */
233 #define TTY_HUPPED 		18	/* Post driver->hangup() */
234 #define TTY_HUPPING		19	/* Hangup in progress */
235 #define TTY_LDISC_CHANGING	20	/* Change pending - non-block IO */
236 #define TTY_LDISC_HALTED	22	/* Line discipline is halted */
237 
tty_io_nonblock(struct tty_struct * tty,struct file * file)238 static inline bool tty_io_nonblock(struct tty_struct *tty, struct file *file)
239 {
240 	return file->f_flags & O_NONBLOCK ||
241 		test_bit(TTY_LDISC_CHANGING, &tty->flags);
242 }
243 
tty_io_error(struct tty_struct * tty)244 static inline bool tty_io_error(struct tty_struct *tty)
245 {
246 	return test_bit(TTY_IO_ERROR, &tty->flags);
247 }
248 
tty_throttled(struct tty_struct * tty)249 static inline bool tty_throttled(struct tty_struct *tty)
250 {
251 	return test_bit(TTY_THROTTLED, &tty->flags);
252 }
253 
254 #ifdef CONFIG_TTY
255 void tty_kref_put(struct tty_struct *tty);
256 struct pid *tty_get_pgrp(struct tty_struct *tty);
257 void tty_vhangup_self(void);
258 void disassociate_ctty(int priv);
259 dev_t tty_devnum(struct tty_struct *tty);
260 void proc_clear_tty(struct task_struct *p);
261 struct tty_struct *get_current_tty(void);
262 /* tty_io.c */
263 int __init tty_init(void);
264 const char *tty_name(const struct tty_struct *tty);
265 struct tty_struct *tty_kopen_exclusive(dev_t device);
266 struct tty_struct *tty_kopen_shared(dev_t device);
267 void tty_kclose(struct tty_struct *tty);
268 int tty_dev_name_to_number(const char *name, dev_t *number);
269 #else
tty_kref_put(struct tty_struct * tty)270 static inline void tty_kref_put(struct tty_struct *tty)
271 { }
tty_get_pgrp(struct tty_struct * tty)272 static inline struct pid *tty_get_pgrp(struct tty_struct *tty)
273 { return NULL; }
tty_vhangup_self(void)274 static inline void tty_vhangup_self(void)
275 { }
disassociate_ctty(int priv)276 static inline void disassociate_ctty(int priv)
277 { }
tty_devnum(struct tty_struct * tty)278 static inline dev_t tty_devnum(struct tty_struct *tty)
279 { return 0; }
proc_clear_tty(struct task_struct * p)280 static inline void proc_clear_tty(struct task_struct *p)
281 { }
get_current_tty(void)282 static inline struct tty_struct *get_current_tty(void)
283 { return NULL; }
284 /* tty_io.c */
tty_init(void)285 static inline int __init tty_init(void)
286 { return 0; }
tty_name(const struct tty_struct * tty)287 static inline const char *tty_name(const struct tty_struct *tty)
288 { return "(none)"; }
tty_kopen_exclusive(dev_t device)289 static inline struct tty_struct *tty_kopen_exclusive(dev_t device)
290 { return ERR_PTR(-ENODEV); }
tty_kclose(struct tty_struct * tty)291 static inline void tty_kclose(struct tty_struct *tty)
292 { }
tty_dev_name_to_number(const char * name,dev_t * number)293 static inline int tty_dev_name_to_number(const char *name, dev_t *number)
294 { return -ENOTSUPP; }
295 #endif
296 
297 extern struct ktermios tty_std_termios;
298 
299 int vcs_init(void);
300 
301 extern struct class *tty_class;
302 
303 /**
304  *	tty_kref_get		-	get a tty reference
305  *	@tty: tty device
306  *
307  *	Return a new reference to a tty object. The caller must hold
308  *	sufficient locks/counts to ensure that their existing reference cannot
309  *	go away
310  */
311 
tty_kref_get(struct tty_struct * tty)312 static inline struct tty_struct *tty_kref_get(struct tty_struct *tty)
313 {
314 	if (tty)
315 		kref_get(&tty->kref);
316 	return tty;
317 }
318 
319 const char *tty_driver_name(const struct tty_struct *tty);
320 void tty_wait_until_sent(struct tty_struct *tty, long timeout);
321 void stop_tty(struct tty_struct *tty);
322 void start_tty(struct tty_struct *tty);
323 void tty_write_message(struct tty_struct *tty, char *msg);
324 int tty_send_xchar(struct tty_struct *tty, char ch);
325 int tty_put_char(struct tty_struct *tty, unsigned char c);
326 unsigned int tty_chars_in_buffer(struct tty_struct *tty);
327 unsigned int tty_write_room(struct tty_struct *tty);
328 void tty_driver_flush_buffer(struct tty_struct *tty);
329 void tty_unthrottle(struct tty_struct *tty);
330 int tty_throttle_safe(struct tty_struct *tty);
331 int tty_unthrottle_safe(struct tty_struct *tty);
332 int tty_do_resize(struct tty_struct *tty, struct winsize *ws);
333 int tty_get_icount(struct tty_struct *tty,
334 		struct serial_icounter_struct *icount);
335 int is_current_pgrp_orphaned(void);
336 void tty_hangup(struct tty_struct *tty);
337 void tty_vhangup(struct tty_struct *tty);
338 int tty_hung_up_p(struct file *filp);
339 void do_SAK(struct tty_struct *tty);
340 void __do_SAK(struct tty_struct *tty);
341 void no_tty(void);
342 speed_t tty_termios_baud_rate(struct ktermios *termios);
343 void tty_termios_encode_baud_rate(struct ktermios *termios, speed_t ibaud,
344 		speed_t obaud);
345 void tty_encode_baud_rate(struct tty_struct *tty, speed_t ibaud,
346 		speed_t obaud);
347 
348 /**
349  *	tty_get_baud_rate	-	get tty bit rates
350  *	@tty: tty to query
351  *
352  *	Returns the baud rate as an integer for this terminal. The
353  *	termios lock must be held by the caller and the terminal bit
354  *	flags may be updated.
355  *
356  *	Locking: none
357  */
tty_get_baud_rate(struct tty_struct * tty)358 static inline speed_t tty_get_baud_rate(struct tty_struct *tty)
359 {
360 	return tty_termios_baud_rate(&tty->termios);
361 }
362 
363 unsigned char tty_get_char_size(unsigned int cflag);
364 unsigned char tty_get_frame_size(unsigned int cflag);
365 
366 void tty_termios_copy_hw(struct ktermios *new, struct ktermios *old);
367 int tty_termios_hw_change(const struct ktermios *a, const struct ktermios *b);
368 int tty_set_termios(struct tty_struct *tty, struct ktermios *kt);
369 
370 void tty_wakeup(struct tty_struct *tty);
371 
372 int tty_mode_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg);
373 int tty_perform_flush(struct tty_struct *tty, unsigned long arg);
374 struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx);
375 void tty_release_struct(struct tty_struct *tty, int idx);
376 void tty_init_termios(struct tty_struct *tty);
377 void tty_save_termios(struct tty_struct *tty);
378 int tty_standard_install(struct tty_driver *driver,
379 		struct tty_struct *tty);
380 
381 extern struct mutex tty_mutex;
382 
383 /* n_tty.c */
384 void n_tty_inherit_ops(struct tty_ldisc_ops *ops);
385 #ifdef CONFIG_TTY
386 void __init n_tty_init(void);
387 #else
n_tty_init(void)388 static inline void n_tty_init(void) { }
389 #endif
390 
391 /* tty_audit.c */
392 #ifdef CONFIG_AUDIT
393 void tty_audit_exit(void);
394 void tty_audit_fork(struct signal_struct *sig);
395 int tty_audit_push(void);
396 #else
tty_audit_exit(void)397 static inline void tty_audit_exit(void)
398 {
399 }
tty_audit_fork(struct signal_struct * sig)400 static inline void tty_audit_fork(struct signal_struct *sig)
401 {
402 }
tty_audit_push(void)403 static inline int tty_audit_push(void)
404 {
405 	return 0;
406 }
407 #endif
408 
409 /* tty_ioctl.c */
410 int n_tty_ioctl_helper(struct tty_struct *tty, unsigned int cmd,
411 		unsigned long arg);
412 
413 /* vt.c */
414 
415 int vt_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg);
416 
417 long vt_compat_ioctl(struct tty_struct *tty, unsigned int cmd,
418 		unsigned long arg);
419 
420 /* tty_mutex.c */
421 /* functions for preparation of BKL removal */
422 void tty_lock(struct tty_struct *tty);
423 int  tty_lock_interruptible(struct tty_struct *tty);
424 void tty_unlock(struct tty_struct *tty);
425 void tty_lock_slave(struct tty_struct *tty);
426 void tty_unlock_slave(struct tty_struct *tty);
427 void tty_set_lock_subclass(struct tty_struct *tty);
428 
429 #endif
430