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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_driver.h>
10#include <linux/tty_ldisc.h>
11#include <linux/mutex.h>
12#include <linux/tty_flags.h>
13#include <linux/seq_file.h>
14#include <uapi/linux/tty.h>
15#include <linux/rwsem.h>
16#include <linux/llist.h>
17
18
19/*
20 * Lock subclasses for tty locks
21 *
22 * TTY_LOCK_NORMAL is for normal ttys and master ptys.
23 * TTY_LOCK_SLAVE is for slave ptys only.
24 *
25 * Lock subclasses are necessary for handling nested locking with pty pairs.
26 * tty locks which use nested locking:
27 *
28 * legacy_mutex - Nested tty locks are necessary for releasing pty pairs.
29 * The stable lock order is master pty first, then slave pty.
30 * termios_rwsem - The stable lock order is tty_buffer lock->termios_rwsem.
31 * Subclassing this lock enables the slave pty to hold its
32 * termios_rwsem when claiming the master tty_buffer lock.
33 * tty_buffer lock - slave ptys can claim nested buffer lock when handling
34 * signal chars. The stable lock order is slave pty, then
35 * master.
36 */
37
38enum {
39 TTY_LOCK_NORMAL = 0,
40 TTY_LOCK_SLAVE,
41};
42
43/*
44 * (Note: the *_driver.minor_start values 1, 64, 128, 192 are
45 * hardcoded at present.)
46 */
47#define NR_UNIX98_PTY_DEFAULT 4096 /* Default maximum for Unix98 ptys */
48#define NR_UNIX98_PTY_RESERVE 1024 /* Default reserve for main devpts */
49#define NR_UNIX98_PTY_MAX (1 << MINORBITS) /* Absolute limit */
50
51/*
52 * This character is the same as _POSIX_VDISABLE: it cannot be used as
53 * a c_cc[] character, but indicates that a particular special character
54 * isn't in use (eg VINTR has no character etc)
55 */
56#define __DISABLED_CHAR '\0'
57
58struct tty_buffer {
59 union {
60 struct tty_buffer *next;
61 struct llist_node free;
62 };
63 int used;
64 int size;
65 int commit;
66 int read;
67 int flags;
68 /* Data points here */
69 unsigned long data[];
70};
71
72/* Values for .flags field of tty_buffer */
73#define TTYB_NORMAL 1 /* buffer has no flags buffer */
74
75static inline unsigned char *char_buf_ptr(struct tty_buffer *b, int ofs)
76{
77 return ((unsigned char *)b->data) + ofs;
78}
79
80static inline char *flag_buf_ptr(struct tty_buffer *b, int ofs)
81{
82 return (char *)char_buf_ptr(b, ofs) + b->size;
83}
84
85struct tty_bufhead {
86 struct tty_buffer *head; /* Queue head */
87 struct work_struct work;
88 struct mutex lock;
89 atomic_t priority;
90 struct tty_buffer sentinel;
91 struct llist_head free; /* Free queue head */
92 atomic_t mem_used; /* In-use buffers excluding free list */
93 int mem_limit;
94 struct tty_buffer *tail; /* Active buffer */
95};
96/*
97 * When a break, frame error, or parity error happens, these codes are
98 * stuffed into the flags buffer.
99 */
100#define TTY_NORMAL 0
101#define TTY_BREAK 1
102#define TTY_FRAME 2
103#define TTY_PARITY 3
104#define TTY_OVERRUN 4
105
106#define INTR_CHAR(tty) ((tty)->termios.c_cc[VINTR])
107#define QUIT_CHAR(tty) ((tty)->termios.c_cc[VQUIT])
108#define ERASE_CHAR(tty) ((tty)->termios.c_cc[VERASE])
109#define KILL_CHAR(tty) ((tty)->termios.c_cc[VKILL])
110#define EOF_CHAR(tty) ((tty)->termios.c_cc[VEOF])
111#define TIME_CHAR(tty) ((tty)->termios.c_cc[VTIME])
112#define MIN_CHAR(tty) ((tty)->termios.c_cc[VMIN])
113#define SWTC_CHAR(tty) ((tty)->termios.c_cc[VSWTC])
114#define START_CHAR(tty) ((tty)->termios.c_cc[VSTART])
115#define STOP_CHAR(tty) ((tty)->termios.c_cc[VSTOP])
116#define SUSP_CHAR(tty) ((tty)->termios.c_cc[VSUSP])
117#define EOL_CHAR(tty) ((tty)->termios.c_cc[VEOL])
118#define REPRINT_CHAR(tty) ((tty)->termios.c_cc[VREPRINT])
119#define DISCARD_CHAR(tty) ((tty)->termios.c_cc[VDISCARD])
120#define WERASE_CHAR(tty) ((tty)->termios.c_cc[VWERASE])
121#define LNEXT_CHAR(tty) ((tty)->termios.c_cc[VLNEXT])
122#define EOL2_CHAR(tty) ((tty)->termios.c_cc[VEOL2])
123
124#define _I_FLAG(tty, f) ((tty)->termios.c_iflag & (f))
125#define _O_FLAG(tty, f) ((tty)->termios.c_oflag & (f))
126#define _C_FLAG(tty, f) ((tty)->termios.c_cflag & (f))
127#define _L_FLAG(tty, f) ((tty)->termios.c_lflag & (f))
128
129#define I_IGNBRK(tty) _I_FLAG((tty), IGNBRK)
130#define I_BRKINT(tty) _I_FLAG((tty), BRKINT)
131#define I_IGNPAR(tty) _I_FLAG((tty), IGNPAR)
132#define I_PARMRK(tty) _I_FLAG((tty), PARMRK)
133#define I_INPCK(tty) _I_FLAG((tty), INPCK)
134#define I_ISTRIP(tty) _I_FLAG((tty), ISTRIP)
135#define I_INLCR(tty) _I_FLAG((tty), INLCR)
136#define I_IGNCR(tty) _I_FLAG((tty), IGNCR)
137#define I_ICRNL(tty) _I_FLAG((tty), ICRNL)
138#define I_IUCLC(tty) _I_FLAG((tty), IUCLC)
139#define I_IXON(tty) _I_FLAG((tty), IXON)
140#define I_IXANY(tty) _I_FLAG((tty), IXANY)
141#define I_IXOFF(tty) _I_FLAG((tty), IXOFF)
142#define I_IMAXBEL(tty) _I_FLAG((tty), IMAXBEL)
143#define I_IUTF8(tty) _I_FLAG((tty), IUTF8)
144
145#define O_OPOST(tty) _O_FLAG((tty), OPOST)
146#define O_OLCUC(tty) _O_FLAG((tty), OLCUC)
147#define O_ONLCR(tty) _O_FLAG((tty), ONLCR)
148#define O_OCRNL(tty) _O_FLAG((tty), OCRNL)
149#define O_ONOCR(tty) _O_FLAG((tty), ONOCR)
150#define O_ONLRET(tty) _O_FLAG((tty), ONLRET)
151#define O_OFILL(tty) _O_FLAG((tty), OFILL)
152#define O_OFDEL(tty) _O_FLAG((tty), OFDEL)
153#define O_NLDLY(tty) _O_FLAG((tty), NLDLY)
154#define O_CRDLY(tty) _O_FLAG((tty), CRDLY)
155#define O_TABDLY(tty) _O_FLAG((tty), TABDLY)
156#define O_BSDLY(tty) _O_FLAG((tty), BSDLY)
157#define O_VTDLY(tty) _O_FLAG((tty), VTDLY)
158#define O_FFDLY(tty) _O_FLAG((tty), FFDLY)
159
160#define C_BAUD(tty) _C_FLAG((tty), CBAUD)
161#define C_CSIZE(tty) _C_FLAG((tty), CSIZE)
162#define C_CSTOPB(tty) _C_FLAG((tty), CSTOPB)
163#define C_CREAD(tty) _C_FLAG((tty), CREAD)
164#define C_PARENB(tty) _C_FLAG((tty), PARENB)
165#define C_PARODD(tty) _C_FLAG((tty), PARODD)
166#define C_HUPCL(tty) _C_FLAG((tty), HUPCL)
167#define C_CLOCAL(tty) _C_FLAG((tty), CLOCAL)
168#define C_CIBAUD(tty) _C_FLAG((tty), CIBAUD)
169#define C_CRTSCTS(tty) _C_FLAG((tty), CRTSCTS)
170#define C_CMSPAR(tty) _C_FLAG((tty), CMSPAR)
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
189struct device;
190struct 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
203struct tty_port;
204
205struct 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 /* Called under the port mutex from tty_port_open, serialized using
215 the port mutex */
216 /* FIXME: long term getting the tty argument *out* of this would be
217 good for consoles */
218 int (*activate)(struct tty_port *port, struct tty_struct *tty);
219 /* Called on the final put of a port */
220 void (*destruct)(struct tty_port *port);
221};
222
223struct tty_port_client_operations {
224 int (*receive_buf)(struct tty_port *port, const unsigned char *, const unsigned char *, size_t);
225 void (*write_wakeup)(struct tty_port *port);
226};
227
228extern const struct tty_port_client_operations tty_port_default_client_ops;
229
230struct tty_port {
231 struct tty_bufhead buf; /* Locked internally */
232 struct tty_struct *tty; /* Back pointer */
233 struct tty_struct *itty; /* internal back ptr */
234 const struct tty_port_operations *ops; /* Port operations */
235 const struct tty_port_client_operations *client_ops; /* Port client operations */
236 spinlock_t lock; /* Lock protecting tty field */
237 int blocked_open; /* Waiting to open */
238 int count; /* Usage count */
239 wait_queue_head_t open_wait; /* Open waiters */
240 wait_queue_head_t delta_msr_wait; /* Modem status change */
241 unsigned long flags; /* User TTY flags ASYNC_ */
242 unsigned long iflags; /* Internal flags TTY_PORT_ */
243 unsigned char console:1, /* port is a console */
244 low_latency:1; /* optional: tune for latency */
245 struct mutex mutex; /* Locking */
246 struct mutex buf_mutex; /* Buffer alloc lock */
247 unsigned char *xmit_buf; /* Optional buffer */
248 unsigned int close_delay; /* Close port delay */
249 unsigned int closing_wait; /* Delay for output */
250 int drain_delay; /* Set to zero if no pure time
251 based drain is needed else
252 set to size of fifo */
253 struct kref kref; /* Ref counter */
254 void *client_data;
255};
256
257/* tty_port::iflags bits -- use atomic bit ops */
258#define TTY_PORT_INITIALIZED 0 /* device is initialized */
259#define TTY_PORT_SUSPENDED 1 /* device is suspended */
260#define TTY_PORT_ACTIVE 2 /* device is open */
261
262/*
263 * uart drivers: use the uart_port::status field and the UPSTAT_* defines
264 * for s/w-based flow control steering and carrier detection status
265 */
266#define TTY_PORT_CTS_FLOW 3 /* h/w flow control enabled */
267#define TTY_PORT_CHECK_CD 4 /* carrier detect enabled */
268#define TTY_PORT_KOPENED 5 /* device exclusively opened by
269 kernel */
270
271/*
272 * Where all of the state associated with a tty is kept while the tty
273 * is open. Since the termios state should be kept even if the tty
274 * has been closed --- for things like the baud rate, etc --- it is
275 * not stored here, but rather a pointer to the real state is stored
276 * here. Possible the winsize structure should have the same
277 * treatment, but (1) the default 80x24 is usually right and (2) it's
278 * most often used by a windowing system, which will set the correct
279 * size each time the window is created or resized anyway.
280 * - TYT, 9/14/92
281 */
282
283struct tty_operations;
284
285struct tty_struct {
286 int magic;
287 struct kref kref;
288 struct device *dev;
289 struct tty_driver *driver;
290 const struct tty_operations *ops;
291 int index;
292
293 /* Protects ldisc changes: Lock tty not pty */
294 struct ld_semaphore ldisc_sem;
295 struct tty_ldisc *ldisc;
296
297 struct mutex atomic_write_lock;
298 struct mutex legacy_mutex;
299 struct mutex throttle_mutex;
300 struct rw_semaphore termios_rwsem;
301 struct mutex winsize_mutex;
302 spinlock_t ctrl_lock;
303 spinlock_t flow_lock;
304 /* Termios values are protected by the termios rwsem */
305 struct ktermios termios, termios_locked;
306 struct termiox *termiox; /* May be NULL for unsupported */
307 char name[64];
308 struct pid *pgrp; /* Protected by ctrl lock */
309 struct pid *session;
310 unsigned long flags;
311 int count;
312 struct winsize winsize; /* winsize_mutex */
313 unsigned long stopped:1, /* flow_lock */
314 flow_stopped:1,
315 unused:BITS_PER_LONG - 2;
316 int hw_stopped;
317 unsigned long ctrl_status:8, /* ctrl_lock */
318 packet:1,
319 unused_ctrl:BITS_PER_LONG - 9;
320 unsigned int receive_room; /* Bytes free for queue */
321 int flow_change;
322
323 struct tty_struct *link;
324 struct fasync_struct *fasync;
325 wait_queue_head_t write_wait;
326 wait_queue_head_t read_wait;
327 struct work_struct hangup_work;
328 void *disc_data;
329 void *driver_data;
330 spinlock_t files_lock; /* protects tty_files list */
331 struct list_head tty_files;
332
333#define N_TTY_BUF_SIZE 4096
334
335 int closing;
336 unsigned char *write_buf;
337 int write_cnt;
338 /* If the tty has a pending do_SAK, queue it here - akpm */
339 struct work_struct SAK_work;
340 struct tty_port *port;
341} __randomize_layout;
342
343/* Each of a tty's open files has private_data pointing to tty_file_private */
344struct tty_file_private {
345 struct tty_struct *tty;
346 struct file *file;
347 struct list_head list;
348};
349
350/* tty magic number */
351#define TTY_MAGIC 0x5401
352
353/*
354 * These bits are used in the flags field of the tty structure.
355 *
356 * So that interrupts won't be able to mess up the queues,
357 * copy_to_cooked must be atomic with respect to itself, as must
358 * tty->write. Thus, you must use the inline functions set_bit() and
359 * clear_bit() to make things atomic.
360 */
361#define TTY_THROTTLED 0 /* Call unthrottle() at threshold min */
362#define TTY_IO_ERROR 1 /* Cause an I/O error (may be no ldisc too) */
363#define TTY_OTHER_CLOSED 2 /* Other side (if any) has closed */
364#define TTY_EXCLUSIVE 3 /* Exclusive open mode */
365#define TTY_DO_WRITE_WAKEUP 5 /* Call write_wakeup after queuing new */
366#define TTY_LDISC_OPEN 11 /* Line discipline is open */
367#define TTY_PTY_LOCK 16 /* pty private */
368#define TTY_NO_WRITE_SPLIT 17 /* Preserve write boundaries to driver */
369#define TTY_HUPPED 18 /* Post driver->hangup() */
370#define TTY_HUPPING 19 /* Hangup in progress */
371#define TTY_LDISC_CHANGING 20 /* Change pending - non-block IO */
372#define TTY_LDISC_HALTED 22 /* Line discipline is halted */
373
374/* Values for tty->flow_change */
375#define TTY_THROTTLE_SAFE 1
376#define TTY_UNTHROTTLE_SAFE 2
377
378static inline void __tty_set_flow_change(struct tty_struct *tty, int val)
379{
380 tty->flow_change = val;
381}
382
383static inline void tty_set_flow_change(struct tty_struct *tty, int val)
384{
385 tty->flow_change = val;
386 smp_mb();
387}
388
389static inline bool tty_io_nonblock(struct tty_struct *tty, struct file *file)
390{
391 return file->f_flags & O_NONBLOCK ||
392 test_bit(TTY_LDISC_CHANGING, &tty->flags);
393}
394
395static inline bool tty_io_error(struct tty_struct *tty)
396{
397 return test_bit(TTY_IO_ERROR, &tty->flags);
398}
399
400static inline bool tty_throttled(struct tty_struct *tty)
401{
402 return test_bit(TTY_THROTTLED, &tty->flags);
403}
404
405#ifdef CONFIG_TTY
406extern void tty_kref_put(struct tty_struct *tty);
407extern struct pid *tty_get_pgrp(struct tty_struct *tty);
408extern void tty_vhangup_self(void);
409extern void disassociate_ctty(int priv);
410extern dev_t tty_devnum(struct tty_struct *tty);
411extern void proc_clear_tty(struct task_struct *p);
412extern struct tty_struct *get_current_tty(void);
413/* tty_io.c */
414extern int __init tty_init(void);
415extern const char *tty_name(const struct tty_struct *tty);
416extern struct tty_struct *tty_kopen(dev_t device);
417extern void tty_kclose(struct tty_struct *tty);
418extern int tty_dev_name_to_number(const char *name, dev_t *number);
419extern int tty_ldisc_lock(struct tty_struct *tty, unsigned long timeout);
420extern void tty_ldisc_unlock(struct tty_struct *tty);
421#else
422static inline void tty_kref_put(struct tty_struct *tty)
423{ }
424static inline struct pid *tty_get_pgrp(struct tty_struct *tty)
425{ return NULL; }
426static inline void tty_vhangup_self(void)
427{ }
428static inline void disassociate_ctty(int priv)
429{ }
430static inline dev_t tty_devnum(struct tty_struct *tty)
431{ return 0; }
432static inline void proc_clear_tty(struct task_struct *p)
433{ }
434static inline struct tty_struct *get_current_tty(void)
435{ return NULL; }
436/* tty_io.c */
437static inline int __init tty_init(void)
438{ return 0; }
439static inline const char *tty_name(const struct tty_struct *tty)
440{ return "(none)"; }
441static inline struct tty_struct *tty_kopen(dev_t device)
442{ return ERR_PTR(-ENODEV); }
443static inline void tty_kclose(struct tty_struct *tty)
444{ }
445static inline int tty_dev_name_to_number(const char *name, dev_t *number)
446{ return -ENOTSUPP; }
447#endif
448
449extern struct ktermios tty_std_termios;
450
451extern int vcs_init(void);
452
453extern struct class *tty_class;
454
455/**
456 * tty_kref_get - get a tty reference
457 * @tty: tty device
458 *
459 * Return a new reference to a tty object. The caller must hold
460 * sufficient locks/counts to ensure that their existing reference cannot
461 * go away
462 */
463
464static inline struct tty_struct *tty_kref_get(struct tty_struct *tty)
465{
466 if (tty)
467 kref_get(&tty->kref);
468 return tty;
469}
470
471extern const char *tty_driver_name(const struct tty_struct *tty);
472extern void tty_wait_until_sent(struct tty_struct *tty, long timeout);
473extern int __tty_check_change(struct tty_struct *tty, int sig);
474extern int tty_check_change(struct tty_struct *tty);
475extern void __stop_tty(struct tty_struct *tty);
476extern void stop_tty(struct tty_struct *tty);
477extern void __start_tty(struct tty_struct *tty);
478extern void start_tty(struct tty_struct *tty);
479extern int tty_register_driver(struct tty_driver *driver);
480extern int tty_unregister_driver(struct tty_driver *driver);
481extern struct device *tty_register_device(struct tty_driver *driver,
482 unsigned index, struct device *dev);
483extern struct device *tty_register_device_attr(struct tty_driver *driver,
484 unsigned index, struct device *device,
485 void *drvdata,
486 const struct attribute_group **attr_grp);
487extern void tty_unregister_device(struct tty_driver *driver, unsigned index);
488extern void tty_write_message(struct tty_struct *tty, char *msg);
489extern int tty_send_xchar(struct tty_struct *tty, char ch);
490extern int tty_put_char(struct tty_struct *tty, unsigned char c);
491extern int tty_chars_in_buffer(struct tty_struct *tty);
492extern int tty_write_room(struct tty_struct *tty);
493extern void tty_driver_flush_buffer(struct tty_struct *tty);
494extern void tty_throttle(struct tty_struct *tty);
495extern void tty_unthrottle(struct tty_struct *tty);
496extern int tty_throttle_safe(struct tty_struct *tty);
497extern int tty_unthrottle_safe(struct tty_struct *tty);
498extern int tty_do_resize(struct tty_struct *tty, struct winsize *ws);
499extern int is_current_pgrp_orphaned(void);
500extern void tty_hangup(struct tty_struct *tty);
501extern void tty_vhangup(struct tty_struct *tty);
502extern void tty_vhangup_session(struct tty_struct *tty);
503extern int tty_hung_up_p(struct file *filp);
504extern void do_SAK(struct tty_struct *tty);
505extern void __do_SAK(struct tty_struct *tty);
506extern void tty_open_proc_set_tty(struct file *filp, struct tty_struct *tty);
507extern int tty_signal_session_leader(struct tty_struct *tty, int exit_session);
508extern void session_clear_tty(struct pid *session);
509extern void no_tty(void);
510extern void tty_buffer_free_all(struct tty_port *port);
511extern void tty_buffer_flush(struct tty_struct *tty, struct tty_ldisc *ld);
512extern void tty_buffer_init(struct tty_port *port);
513extern void tty_buffer_set_lock_subclass(struct tty_port *port);
514extern bool tty_buffer_restart_work(struct tty_port *port);
515extern bool tty_buffer_cancel_work(struct tty_port *port);
516extern void tty_buffer_flush_work(struct tty_port *port);
517extern speed_t tty_termios_baud_rate(struct ktermios *termios);
518extern speed_t tty_termios_input_baud_rate(struct ktermios *termios);
519extern void tty_termios_encode_baud_rate(struct ktermios *termios,
520 speed_t ibaud, speed_t obaud);
521extern void tty_encode_baud_rate(struct tty_struct *tty,
522 speed_t ibaud, speed_t obaud);
523
524/**
525 * tty_get_baud_rate - get tty bit rates
526 * @tty: tty to query
527 *
528 * Returns the baud rate as an integer for this terminal. The
529 * termios lock must be held by the caller and the terminal bit
530 * flags may be updated.
531 *
532 * Locking: none
533 */
534static inline speed_t tty_get_baud_rate(struct tty_struct *tty)
535{
536 return tty_termios_baud_rate(&tty->termios);
537}
538
539extern void tty_termios_copy_hw(struct ktermios *new, struct ktermios *old);
540extern int tty_termios_hw_change(const struct ktermios *a, const struct ktermios *b);
541extern int tty_set_termios(struct tty_struct *tty, struct ktermios *kt);
542
543extern struct tty_ldisc *tty_ldisc_ref(struct tty_struct *);
544extern void tty_ldisc_deref(struct tty_ldisc *);
545extern struct tty_ldisc *tty_ldisc_ref_wait(struct tty_struct *);
546extern void tty_ldisc_hangup(struct tty_struct *tty, bool reset);
547extern int tty_ldisc_reinit(struct tty_struct *tty, int disc);
548extern const struct seq_operations tty_ldiscs_seq_ops;
549
550extern void tty_wakeup(struct tty_struct *tty);
551extern void tty_ldisc_flush(struct tty_struct *tty);
552
553extern long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
554extern int tty_mode_ioctl(struct tty_struct *tty, struct file *file,
555 unsigned int cmd, unsigned long arg);
556extern long tty_jobctrl_ioctl(struct tty_struct *tty, struct tty_struct *real_tty,
557 struct file *file, unsigned int cmd, unsigned long arg);
558extern int tty_perform_flush(struct tty_struct *tty, unsigned long arg);
559extern void tty_default_fops(struct file_operations *fops);
560extern struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx);
561extern int tty_alloc_file(struct file *file);
562extern void tty_add_file(struct tty_struct *tty, struct file *file);
563extern void tty_free_file(struct file *file);
564extern struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx);
565extern void tty_release_struct(struct tty_struct *tty, int idx);
566extern int tty_release(struct inode *inode, struct file *filp);
567extern void tty_init_termios(struct tty_struct *tty);
568extern void tty_save_termios(struct tty_struct *tty);
569extern int tty_standard_install(struct tty_driver *driver,
570 struct tty_struct *tty);
571
572extern struct mutex tty_mutex;
573
574#define tty_is_writelocked(tty) (mutex_is_locked(&tty->atomic_write_lock))
575
576extern void tty_port_init(struct tty_port *port);
577extern void tty_port_link_device(struct tty_port *port,
578 struct tty_driver *driver, unsigned index);
579extern struct device *tty_port_register_device(struct tty_port *port,
580 struct tty_driver *driver, unsigned index,
581 struct device *device);
582extern struct device *tty_port_register_device_attr(struct tty_port *port,
583 struct tty_driver *driver, unsigned index,
584 struct device *device, void *drvdata,
585 const struct attribute_group **attr_grp);
586extern struct device *tty_port_register_device_serdev(struct tty_port *port,
587 struct tty_driver *driver, unsigned index,
588 struct device *device);
589extern struct device *tty_port_register_device_attr_serdev(struct tty_port *port,
590 struct tty_driver *driver, unsigned index,
591 struct device *device, void *drvdata,
592 const struct attribute_group **attr_grp);
593extern void tty_port_unregister_device(struct tty_port *port,
594 struct tty_driver *driver, unsigned index);
595extern int tty_port_alloc_xmit_buf(struct tty_port *port);
596extern void tty_port_free_xmit_buf(struct tty_port *port);
597extern void tty_port_destroy(struct tty_port *port);
598extern void tty_port_put(struct tty_port *port);
599
600static inline struct tty_port *tty_port_get(struct tty_port *port)
601{
602 if (port && kref_get_unless_zero(&port->kref))
603 return port;
604 return NULL;
605}
606
607/* If the cts flow control is enabled, return true. */
608static inline bool tty_port_cts_enabled(struct tty_port *port)
609{
610 return test_bit(TTY_PORT_CTS_FLOW, &port->iflags);
611}
612
613static inline void tty_port_set_cts_flow(struct tty_port *port, bool val)
614{
615 if (val)
616 set_bit(TTY_PORT_CTS_FLOW, &port->iflags);
617 else
618 clear_bit(TTY_PORT_CTS_FLOW, &port->iflags);
619}
620
621static inline bool tty_port_active(struct tty_port *port)
622{
623 return test_bit(TTY_PORT_ACTIVE, &port->iflags);
624}
625
626static inline void tty_port_set_active(struct tty_port *port, bool val)
627{
628 if (val)
629 set_bit(TTY_PORT_ACTIVE, &port->iflags);
630 else
631 clear_bit(TTY_PORT_ACTIVE, &port->iflags);
632}
633
634static inline bool tty_port_check_carrier(struct tty_port *port)
635{
636 return test_bit(TTY_PORT_CHECK_CD, &port->iflags);
637}
638
639static inline void tty_port_set_check_carrier(struct tty_port *port, bool val)
640{
641 if (val)
642 set_bit(TTY_PORT_CHECK_CD, &port->iflags);
643 else
644 clear_bit(TTY_PORT_CHECK_CD, &port->iflags);
645}
646
647static inline bool tty_port_suspended(struct tty_port *port)
648{
649 return test_bit(TTY_PORT_SUSPENDED, &port->iflags);
650}
651
652static inline void tty_port_set_suspended(struct tty_port *port, bool val)
653{
654 if (val)
655 set_bit(TTY_PORT_SUSPENDED, &port->iflags);
656 else
657 clear_bit(TTY_PORT_SUSPENDED, &port->iflags);
658}
659
660static inline bool tty_port_initialized(struct tty_port *port)
661{
662 return test_bit(TTY_PORT_INITIALIZED, &port->iflags);
663}
664
665static inline void tty_port_set_initialized(struct tty_port *port, bool val)
666{
667 if (val)
668 set_bit(TTY_PORT_INITIALIZED, &port->iflags);
669 else
670 clear_bit(TTY_PORT_INITIALIZED, &port->iflags);
671}
672
673static inline bool tty_port_kopened(struct tty_port *port)
674{
675 return test_bit(TTY_PORT_KOPENED, &port->iflags);
676}
677
678static inline void tty_port_set_kopened(struct tty_port *port, bool val)
679{
680 if (val)
681 set_bit(TTY_PORT_KOPENED, &port->iflags);
682 else
683 clear_bit(TTY_PORT_KOPENED, &port->iflags);
684}
685
686extern struct tty_struct *tty_port_tty_get(struct tty_port *port);
687extern void tty_port_tty_set(struct tty_port *port, struct tty_struct *tty);
688extern int tty_port_carrier_raised(struct tty_port *port);
689extern void tty_port_raise_dtr_rts(struct tty_port *port);
690extern void tty_port_lower_dtr_rts(struct tty_port *port);
691extern void tty_port_hangup(struct tty_port *port);
692extern void tty_port_tty_hangup(struct tty_port *port, bool check_clocal);
693extern void tty_port_tty_wakeup(struct tty_port *port);
694extern int tty_port_block_til_ready(struct tty_port *port,
695 struct tty_struct *tty, struct file *filp);
696extern int tty_port_close_start(struct tty_port *port,
697 struct tty_struct *tty, struct file *filp);
698extern void tty_port_close_end(struct tty_port *port, struct tty_struct *tty);
699extern void tty_port_close(struct tty_port *port,
700 struct tty_struct *tty, struct file *filp);
701extern int tty_port_install(struct tty_port *port, struct tty_driver *driver,
702 struct tty_struct *tty);
703extern int tty_port_open(struct tty_port *port,
704 struct tty_struct *tty, struct file *filp);
705static inline int tty_port_users(struct tty_port *port)
706{
707 return port->count + port->blocked_open;
708}
709
710extern int tty_register_ldisc(int disc, struct tty_ldisc_ops *new_ldisc);
711extern int tty_unregister_ldisc(int disc);
712extern int tty_set_ldisc(struct tty_struct *tty, int disc);
713extern int tty_ldisc_setup(struct tty_struct *tty, struct tty_struct *o_tty);
714extern void tty_ldisc_release(struct tty_struct *tty);
715extern int __must_check tty_ldisc_init(struct tty_struct *tty);
716extern void tty_ldisc_deinit(struct tty_struct *tty);
717extern int tty_ldisc_receive_buf(struct tty_ldisc *ld, const unsigned char *p,
718 char *f, int count);
719
720/* n_tty.c */
721extern void n_tty_inherit_ops(struct tty_ldisc_ops *ops);
722#ifdef CONFIG_TTY
723extern void __init n_tty_init(void);
724#else
725static inline void n_tty_init(void) { }
726#endif
727
728/* tty_audit.c */
729#ifdef CONFIG_AUDIT
730extern void tty_audit_add_data(struct tty_struct *tty, const void *data,
731 size_t size);
732extern void tty_audit_exit(void);
733extern void tty_audit_fork(struct signal_struct *sig);
734extern void tty_audit_tiocsti(struct tty_struct *tty, char ch);
735extern int tty_audit_push(void);
736#else
737static inline void tty_audit_add_data(struct tty_struct *tty, const void *data,
738 size_t size)
739{
740}
741static inline void tty_audit_tiocsti(struct tty_struct *tty, char ch)
742{
743}
744static inline void tty_audit_exit(void)
745{
746}
747static inline void tty_audit_fork(struct signal_struct *sig)
748{
749}
750static inline int tty_audit_push(void)
751{
752 return 0;
753}
754#endif
755
756/* tty_ioctl.c */
757extern int n_tty_ioctl_helper(struct tty_struct *tty, struct file *file,
758 unsigned int cmd, unsigned long arg);
759
760/* vt.c */
761
762extern int vt_ioctl(struct tty_struct *tty,
763 unsigned int cmd, unsigned long arg);
764
765extern long vt_compat_ioctl(struct tty_struct *tty,
766 unsigned int cmd, unsigned long arg);
767
768/* tty_mutex.c */
769/* functions for preparation of BKL removal */
770extern void tty_lock(struct tty_struct *tty);
771extern int tty_lock_interruptible(struct tty_struct *tty);
772extern void tty_unlock(struct tty_struct *tty);
773extern void tty_lock_slave(struct tty_struct *tty);
774extern void tty_unlock_slave(struct tty_struct *tty);
775extern void tty_set_lock_subclass(struct tty_struct *tty);
776
777#ifdef CONFIG_PROC_FS
778extern void proc_tty_register_driver(struct tty_driver *);
779extern void proc_tty_unregister_driver(struct tty_driver *);
780#else
781static inline void proc_tty_register_driver(struct tty_driver *d) {}
782static inline void proc_tty_unregister_driver(struct tty_driver *d) {}
783#endif
784
785#define tty_msg(fn, tty, f, ...) \
786 fn("%s %s: " f, tty_driver_name(tty), tty_name(tty), ##__VA_ARGS__)
787
788#define tty_debug(tty, f, ...) tty_msg(pr_debug, tty, f, ##__VA_ARGS__)
789#define tty_info(tty, f, ...) tty_msg(pr_info, tty, f, ##__VA_ARGS__)
790#define tty_notice(tty, f, ...) tty_msg(pr_notice, tty, f, ##__VA_ARGS__)
791#define tty_warn(tty, f, ...) tty_msg(pr_warn, tty, f, ##__VA_ARGS__)
792#define tty_err(tty, f, ...) tty_msg(pr_err, tty, f, ##__VA_ARGS__)
793
794#define tty_info_ratelimited(tty, f, ...) \
795 tty_msg(pr_info_ratelimited, tty, f, ##__VA_ARGS__)
796
797#endif
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_driver.h>
10#include <linux/tty_ldisc.h>
11#include <linux/tty_port.h>
12#include <linux/mutex.h>
13#include <linux/tty_flags.h>
14#include <uapi/linux/tty.h>
15#include <linux/rwsem.h>
16#include <linux/llist.h>
17
18
19/*
20 * (Note: the *_driver.minor_start values 1, 64, 128, 192 are
21 * hardcoded at present.)
22 */
23#define NR_UNIX98_PTY_DEFAULT 4096 /* Default maximum for Unix98 ptys */
24#define NR_UNIX98_PTY_RESERVE 1024 /* Default reserve for main devpts */
25#define NR_UNIX98_PTY_MAX (1 << MINORBITS) /* Absolute limit */
26
27/*
28 * This character is the same as _POSIX_VDISABLE: it cannot be used as
29 * a c_cc[] character, but indicates that a particular special character
30 * isn't in use (eg VINTR has no character etc)
31 */
32#define __DISABLED_CHAR '\0'
33
34#define INTR_CHAR(tty) ((tty)->termios.c_cc[VINTR])
35#define QUIT_CHAR(tty) ((tty)->termios.c_cc[VQUIT])
36#define ERASE_CHAR(tty) ((tty)->termios.c_cc[VERASE])
37#define KILL_CHAR(tty) ((tty)->termios.c_cc[VKILL])
38#define EOF_CHAR(tty) ((tty)->termios.c_cc[VEOF])
39#define TIME_CHAR(tty) ((tty)->termios.c_cc[VTIME])
40#define MIN_CHAR(tty) ((tty)->termios.c_cc[VMIN])
41#define SWTC_CHAR(tty) ((tty)->termios.c_cc[VSWTC])
42#define START_CHAR(tty) ((tty)->termios.c_cc[VSTART])
43#define STOP_CHAR(tty) ((tty)->termios.c_cc[VSTOP])
44#define SUSP_CHAR(tty) ((tty)->termios.c_cc[VSUSP])
45#define EOL_CHAR(tty) ((tty)->termios.c_cc[VEOL])
46#define REPRINT_CHAR(tty) ((tty)->termios.c_cc[VREPRINT])
47#define DISCARD_CHAR(tty) ((tty)->termios.c_cc[VDISCARD])
48#define WERASE_CHAR(tty) ((tty)->termios.c_cc[VWERASE])
49#define LNEXT_CHAR(tty) ((tty)->termios.c_cc[VLNEXT])
50#define EOL2_CHAR(tty) ((tty)->termios.c_cc[VEOL2])
51
52#define _I_FLAG(tty, f) ((tty)->termios.c_iflag & (f))
53#define _O_FLAG(tty, f) ((tty)->termios.c_oflag & (f))
54#define _C_FLAG(tty, f) ((tty)->termios.c_cflag & (f))
55#define _L_FLAG(tty, f) ((tty)->termios.c_lflag & (f))
56
57#define I_IGNBRK(tty) _I_FLAG((tty), IGNBRK)
58#define I_BRKINT(tty) _I_FLAG((tty), BRKINT)
59#define I_IGNPAR(tty) _I_FLAG((tty), IGNPAR)
60#define I_PARMRK(tty) _I_FLAG((tty), PARMRK)
61#define I_INPCK(tty) _I_FLAG((tty), INPCK)
62#define I_ISTRIP(tty) _I_FLAG((tty), ISTRIP)
63#define I_INLCR(tty) _I_FLAG((tty), INLCR)
64#define I_IGNCR(tty) _I_FLAG((tty), IGNCR)
65#define I_ICRNL(tty) _I_FLAG((tty), ICRNL)
66#define I_IUCLC(tty) _I_FLAG((tty), IUCLC)
67#define I_IXON(tty) _I_FLAG((tty), IXON)
68#define I_IXANY(tty) _I_FLAG((tty), IXANY)
69#define I_IXOFF(tty) _I_FLAG((tty), IXOFF)
70#define I_IMAXBEL(tty) _I_FLAG((tty), IMAXBEL)
71#define I_IUTF8(tty) _I_FLAG((tty), IUTF8)
72
73#define O_OPOST(tty) _O_FLAG((tty), OPOST)
74#define O_OLCUC(tty) _O_FLAG((tty), OLCUC)
75#define O_ONLCR(tty) _O_FLAG((tty), ONLCR)
76#define O_OCRNL(tty) _O_FLAG((tty), OCRNL)
77#define O_ONOCR(tty) _O_FLAG((tty), ONOCR)
78#define O_ONLRET(tty) _O_FLAG((tty), ONLRET)
79#define O_OFILL(tty) _O_FLAG((tty), OFILL)
80#define O_OFDEL(tty) _O_FLAG((tty), OFDEL)
81#define O_NLDLY(tty) _O_FLAG((tty), NLDLY)
82#define O_CRDLY(tty) _O_FLAG((tty), CRDLY)
83#define O_TABDLY(tty) _O_FLAG((tty), TABDLY)
84#define O_BSDLY(tty) _O_FLAG((tty), BSDLY)
85#define O_VTDLY(tty) _O_FLAG((tty), VTDLY)
86#define O_FFDLY(tty) _O_FLAG((tty), FFDLY)
87
88#define C_BAUD(tty) _C_FLAG((tty), CBAUD)
89#define C_CSIZE(tty) _C_FLAG((tty), CSIZE)
90#define C_CSTOPB(tty) _C_FLAG((tty), CSTOPB)
91#define C_CREAD(tty) _C_FLAG((tty), CREAD)
92#define C_PARENB(tty) _C_FLAG((tty), PARENB)
93#define C_PARODD(tty) _C_FLAG((tty), PARODD)
94#define C_HUPCL(tty) _C_FLAG((tty), HUPCL)
95#define C_CLOCAL(tty) _C_FLAG((tty), CLOCAL)
96#define C_CIBAUD(tty) _C_FLAG((tty), CIBAUD)
97#define C_CRTSCTS(tty) _C_FLAG((tty), CRTSCTS)
98#define C_CMSPAR(tty) _C_FLAG((tty), CMSPAR)
99
100#define L_ISIG(tty) _L_FLAG((tty), ISIG)
101#define L_ICANON(tty) _L_FLAG((tty), ICANON)
102#define L_XCASE(tty) _L_FLAG((tty), XCASE)
103#define L_ECHO(tty) _L_FLAG((tty), ECHO)
104#define L_ECHOE(tty) _L_FLAG((tty), ECHOE)
105#define L_ECHOK(tty) _L_FLAG((tty), ECHOK)
106#define L_ECHONL(tty) _L_FLAG((tty), ECHONL)
107#define L_NOFLSH(tty) _L_FLAG((tty), NOFLSH)
108#define L_TOSTOP(tty) _L_FLAG((tty), TOSTOP)
109#define L_ECHOCTL(tty) _L_FLAG((tty), ECHOCTL)
110#define L_ECHOPRT(tty) _L_FLAG((tty), ECHOPRT)
111#define L_ECHOKE(tty) _L_FLAG((tty), ECHOKE)
112#define L_FLUSHO(tty) _L_FLAG((tty), FLUSHO)
113#define L_PENDIN(tty) _L_FLAG((tty), PENDIN)
114#define L_IEXTEN(tty) _L_FLAG((tty), IEXTEN)
115#define L_EXTPROC(tty) _L_FLAG((tty), EXTPROC)
116
117struct device;
118struct signal_struct;
119struct tty_operations;
120
121/**
122 * struct tty_struct - state associated with a tty while open
123 *
124 * @kref: reference counting by tty_kref_get() and tty_kref_put(), reaching zero
125 * frees the structure
126 * @dev: class device or %NULL (e.g. ptys, serdev)
127 * @driver: &struct tty_driver operating this tty
128 * @ops: &struct tty_operations of @driver for this tty (open, close, etc.)
129 * @index: index of this tty (e.g. to construct @name like tty12)
130 * @ldisc_sem: protects line discipline changes (@ldisc) -- lock tty not pty
131 * @ldisc: the current line discipline for this tty (n_tty by default)
132 * @atomic_write_lock: protects against concurrent writers, i.e. locks
133 * @write_cnt, @write_buf and similar
134 * @legacy_mutex: leftover from history (BKL -> BTM -> @legacy_mutex),
135 * protecting several operations on this tty
136 * @throttle_mutex: protects against concurrent tty_throttle_safe() and
137 * tty_unthrottle_safe() (but not tty_unthrottle())
138 * @termios_rwsem: protects @termios and @termios_locked
139 * @winsize_mutex: protects @winsize
140 * @termios: termios for the current tty, copied from/to @driver.termios
141 * @termios_locked: locked termios (by %TIOCGLCKTRMIOS and %TIOCSLCKTRMIOS
142 * ioctls)
143 * @name: name of the tty constructed by tty_line_name() (e.g. ttyS3)
144 * @flags: bitwise OR of %TTY_THROTTLED, %TTY_IO_ERROR, ...
145 * @count: count of open processes, reaching zero cancels all the work for
146 * this tty and drops a @kref too (but does not free this tty)
147 * @winsize: size of the terminal "window" (cf. @winsize_mutex)
148 * @flow: flow settings grouped together
149 * @flow.lock: lock for @flow members
150 * @flow.stopped: tty stopped/started by stop_tty()/start_tty()
151 * @flow.tco_stopped: tty stopped/started by %TCOOFF/%TCOON ioctls (it has
152 * precedence over @flow.stopped)
153 * @ctrl: control settings grouped together
154 * @ctrl.lock: lock for @ctrl members
155 * @ctrl.pgrp: process group of this tty (setpgrp(2))
156 * @ctrl.session: session of this tty (setsid(2)). Writes are protected by both
157 * @ctrl.lock and @legacy_mutex, readers must use at least one of
158 * them.
159 * @ctrl.pktstatus: packet mode status (bitwise OR of %TIOCPKT_ constants)
160 * @ctrl.packet: packet mode enabled
161 * @hw_stopped: not controlled by the tty layer, under @driver's control for CTS
162 * handling
163 * @receive_room: bytes permitted to feed to @ldisc without any being lost
164 * @flow_change: controls behavior of throttling, see tty_throttle_safe() and
165 * tty_unthrottle_safe()
166 * @link: link to another pty (master -> slave and vice versa)
167 * @fasync: state for %O_ASYNC (for %SIGIO); managed by fasync_helper()
168 * @write_wait: concurrent writers are waiting in this queue until they are
169 * allowed to write
170 * @read_wait: readers wait for data in this queue
171 * @hangup_work: normally a work to perform a hangup (do_tty_hangup()); while
172 * freeing the tty, (re)used to release_one_tty()
173 * @disc_data: pointer to @ldisc's private data (e.g. to &struct n_tty_data)
174 * @driver_data: pointer to @driver's private data (e.g. &struct uart_state)
175 * @files_lock: protects @tty_files list
176 * @tty_files: list of (re)openers of this tty (i.e. linked &struct
177 * tty_file_private)
178 * @closing: when set during close, n_tty processes only START & STOP chars
179 * @write_buf: temporary buffer used during tty_write() to copy user data to
180 * @write_cnt: count of bytes written in tty_write() to @write_buf
181 * @SAK_work: if the tty has a pending do_SAK, it is queued here
182 * @port: persistent storage for this device (i.e. &struct tty_port)
183 *
184 * All of the state associated with a tty while the tty is open. Persistent
185 * storage for tty devices is referenced here as @port and is documented in
186 * &struct tty_port.
187 */
188struct tty_struct {
189 struct kref kref;
190 int index;
191 struct device *dev;
192 struct tty_driver *driver;
193 struct tty_port *port;
194 const struct tty_operations *ops;
195
196 struct tty_ldisc *ldisc;
197 struct ld_semaphore ldisc_sem;
198
199 struct mutex atomic_write_lock;
200 struct mutex legacy_mutex;
201 struct mutex throttle_mutex;
202 struct rw_semaphore termios_rwsem;
203 struct mutex winsize_mutex;
204 struct ktermios termios, termios_locked;
205 char name[64];
206 unsigned long flags;
207 int count;
208 unsigned int receive_room;
209 struct winsize winsize;
210
211 struct {
212 spinlock_t lock;
213 bool stopped;
214 bool tco_stopped;
215 } flow;
216
217 struct {
218 struct pid *pgrp;
219 struct pid *session;
220 spinlock_t lock;
221 unsigned char pktstatus;
222 bool packet;
223 } ctrl;
224
225 bool hw_stopped;
226 bool closing;
227 int flow_change;
228
229 struct tty_struct *link;
230 struct fasync_struct *fasync;
231 wait_queue_head_t write_wait;
232 wait_queue_head_t read_wait;
233 struct work_struct hangup_work;
234 void *disc_data;
235 void *driver_data;
236 spinlock_t files_lock;
237 int write_cnt;
238 u8 *write_buf;
239
240 struct list_head tty_files;
241
242#define N_TTY_BUF_SIZE 4096
243 struct work_struct SAK_work;
244} __randomize_layout;
245
246/* Each of a tty's open files has private_data pointing to tty_file_private */
247struct tty_file_private {
248 struct tty_struct *tty;
249 struct file *file;
250 struct list_head list;
251};
252
253/**
254 * DOC: TTY Struct Flags
255 *
256 * These bits are used in the :c:member:`tty_struct.flags` field.
257 *
258 * So that interrupts won't be able to mess up the queues,
259 * copy_to_cooked must be atomic with respect to itself, as must
260 * tty->write. Thus, you must use the inline functions set_bit() and
261 * clear_bit() to make things atomic.
262 *
263 * TTY_THROTTLED
264 * Driver input is throttled. The ldisc should call
265 * :c:member:`tty_driver.unthrottle()` in order to resume reception when
266 * it is ready to process more data (at threshold min).
267 *
268 * TTY_IO_ERROR
269 * If set, causes all subsequent userspace read/write calls on the tty to
270 * fail, returning -%EIO. (May be no ldisc too.)
271 *
272 * TTY_OTHER_CLOSED
273 * Device is a pty and the other side has closed.
274 *
275 * TTY_EXCLUSIVE
276 * Exclusive open mode (a single opener).
277 *
278 * TTY_DO_WRITE_WAKEUP
279 * If set, causes the driver to call the
280 * :c:member:`tty_ldisc_ops.write_wakeup()` method in order to resume
281 * transmission when it can accept more data to transmit.
282 *
283 * TTY_LDISC_OPEN
284 * Indicates that a line discipline is open. For debugging purposes only.
285 *
286 * TTY_PTY_LOCK
287 * A flag private to pty code to implement %TIOCSPTLCK/%TIOCGPTLCK logic.
288 *
289 * TTY_NO_WRITE_SPLIT
290 * Prevent driver from splitting up writes into smaller chunks (preserve
291 * write boundaries to driver).
292 *
293 * TTY_HUPPED
294 * The TTY was hung up. This is set post :c:member:`tty_driver.hangup()`.
295 *
296 * TTY_HUPPING
297 * The TTY is in the process of hanging up to abort potential readers.
298 *
299 * TTY_LDISC_CHANGING
300 * Line discipline for this TTY is being changed. I/O should not block
301 * when this is set. Use tty_io_nonblock() to check.
302 *
303 * TTY_LDISC_HALTED
304 * Line discipline for this TTY was stopped. No work should be queued to
305 * this ldisc.
306 */
307#define TTY_THROTTLED 0
308#define TTY_IO_ERROR 1
309#define TTY_OTHER_CLOSED 2
310#define TTY_EXCLUSIVE 3
311#define TTY_DO_WRITE_WAKEUP 5
312#define TTY_LDISC_OPEN 11
313#define TTY_PTY_LOCK 16
314#define TTY_NO_WRITE_SPLIT 17
315#define TTY_HUPPED 18
316#define TTY_HUPPING 19
317#define TTY_LDISC_CHANGING 20
318#define TTY_LDISC_HALTED 22
319
320static inline bool tty_io_nonblock(struct tty_struct *tty, struct file *file)
321{
322 return file->f_flags & O_NONBLOCK ||
323 test_bit(TTY_LDISC_CHANGING, &tty->flags);
324}
325
326static inline bool tty_io_error(struct tty_struct *tty)
327{
328 return test_bit(TTY_IO_ERROR, &tty->flags);
329}
330
331static inline bool tty_throttled(struct tty_struct *tty)
332{
333 return test_bit(TTY_THROTTLED, &tty->flags);
334}
335
336#ifdef CONFIG_TTY
337void tty_kref_put(struct tty_struct *tty);
338struct pid *tty_get_pgrp(struct tty_struct *tty);
339void tty_vhangup_self(void);
340void disassociate_ctty(int priv);
341dev_t tty_devnum(struct tty_struct *tty);
342void proc_clear_tty(struct task_struct *p);
343struct tty_struct *get_current_tty(void);
344/* tty_io.c */
345int __init tty_init(void);
346const char *tty_name(const struct tty_struct *tty);
347struct tty_struct *tty_kopen_exclusive(dev_t device);
348struct tty_struct *tty_kopen_shared(dev_t device);
349void tty_kclose(struct tty_struct *tty);
350int tty_dev_name_to_number(const char *name, dev_t *number);
351#else
352static inline void tty_kref_put(struct tty_struct *tty)
353{ }
354static inline struct pid *tty_get_pgrp(struct tty_struct *tty)
355{ return NULL; }
356static inline void tty_vhangup_self(void)
357{ }
358static inline void disassociate_ctty(int priv)
359{ }
360static inline dev_t tty_devnum(struct tty_struct *tty)
361{ return 0; }
362static inline void proc_clear_tty(struct task_struct *p)
363{ }
364static inline struct tty_struct *get_current_tty(void)
365{ return NULL; }
366/* tty_io.c */
367static inline int __init tty_init(void)
368{ return 0; }
369static inline const char *tty_name(const struct tty_struct *tty)
370{ return "(none)"; }
371static inline struct tty_struct *tty_kopen_exclusive(dev_t device)
372{ return ERR_PTR(-ENODEV); }
373static inline void tty_kclose(struct tty_struct *tty)
374{ }
375static inline int tty_dev_name_to_number(const char *name, dev_t *number)
376{ return -ENOTSUPP; }
377#endif
378
379extern struct ktermios tty_std_termios;
380
381int vcs_init(void);
382
383extern const struct class tty_class;
384
385/**
386 * tty_kref_get - get a tty reference
387 * @tty: tty device
388 *
389 * Returns: a new reference to a tty object
390 *
391 * Locking: The caller must hold sufficient locks/counts to ensure that their
392 * existing reference cannot go away.
393 */
394static inline struct tty_struct *tty_kref_get(struct tty_struct *tty)
395{
396 if (tty)
397 kref_get(&tty->kref);
398 return tty;
399}
400
401const char *tty_driver_name(const struct tty_struct *tty);
402void tty_wait_until_sent(struct tty_struct *tty, long timeout);
403void stop_tty(struct tty_struct *tty);
404void start_tty(struct tty_struct *tty);
405void tty_write_message(struct tty_struct *tty, char *msg);
406int tty_send_xchar(struct tty_struct *tty, u8 ch);
407int tty_put_char(struct tty_struct *tty, u8 c);
408unsigned int tty_chars_in_buffer(struct tty_struct *tty);
409unsigned int tty_write_room(struct tty_struct *tty);
410void tty_driver_flush_buffer(struct tty_struct *tty);
411void tty_unthrottle(struct tty_struct *tty);
412bool tty_throttle_safe(struct tty_struct *tty);
413bool tty_unthrottle_safe(struct tty_struct *tty);
414int tty_do_resize(struct tty_struct *tty, struct winsize *ws);
415int tty_get_icount(struct tty_struct *tty,
416 struct serial_icounter_struct *icount);
417int tty_get_tiocm(struct tty_struct *tty);
418int is_current_pgrp_orphaned(void);
419void tty_hangup(struct tty_struct *tty);
420void tty_vhangup(struct tty_struct *tty);
421int tty_hung_up_p(struct file *filp);
422void do_SAK(struct tty_struct *tty);
423void __do_SAK(struct tty_struct *tty);
424void no_tty(void);
425speed_t tty_termios_baud_rate(const struct ktermios *termios);
426void tty_termios_encode_baud_rate(struct ktermios *termios, speed_t ibaud,
427 speed_t obaud);
428void tty_encode_baud_rate(struct tty_struct *tty, speed_t ibaud,
429 speed_t obaud);
430
431/**
432 * tty_get_baud_rate - get tty bit rates
433 * @tty: tty to query
434 *
435 * Returns: the baud rate as an integer for this terminal
436 *
437 * Locking: The termios lock must be held by the caller.
438 */
439static inline speed_t tty_get_baud_rate(const struct tty_struct *tty)
440{
441 return tty_termios_baud_rate(&tty->termios);
442}
443
444unsigned char tty_get_char_size(unsigned int cflag);
445unsigned char tty_get_frame_size(unsigned int cflag);
446
447void tty_termios_copy_hw(struct ktermios *new, const struct ktermios *old);
448bool tty_termios_hw_change(const struct ktermios *a, const struct ktermios *b);
449int tty_set_termios(struct tty_struct *tty, struct ktermios *kt);
450
451void tty_wakeup(struct tty_struct *tty);
452
453int tty_mode_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg);
454int tty_perform_flush(struct tty_struct *tty, unsigned long arg);
455struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx);
456void tty_release_struct(struct tty_struct *tty, int idx);
457void tty_init_termios(struct tty_struct *tty);
458void tty_save_termios(struct tty_struct *tty);
459int tty_standard_install(struct tty_driver *driver,
460 struct tty_struct *tty);
461
462extern struct mutex tty_mutex;
463
464/* n_tty.c */
465void n_tty_inherit_ops(struct tty_ldisc_ops *ops);
466#ifdef CONFIG_TTY
467void __init n_tty_init(void);
468#else
469static inline void n_tty_init(void) { }
470#endif
471
472/* tty_audit.c */
473#ifdef CONFIG_AUDIT
474void tty_audit_exit(void);
475void tty_audit_fork(struct signal_struct *sig);
476int tty_audit_push(void);
477#else
478static inline void tty_audit_exit(void)
479{
480}
481static inline void tty_audit_fork(struct signal_struct *sig)
482{
483}
484static inline int tty_audit_push(void)
485{
486 return 0;
487}
488#endif
489
490/* tty_ioctl.c */
491int n_tty_ioctl_helper(struct tty_struct *tty, unsigned int cmd,
492 unsigned long arg);
493
494/* vt.c */
495
496int vt_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg);
497
498long vt_compat_ioctl(struct tty_struct *tty, unsigned int cmd,
499 unsigned long arg);
500
501/* tty_mutex.c */
502/* functions for preparation of BKL removal */
503void tty_lock(struct tty_struct *tty);
504int tty_lock_interruptible(struct tty_struct *tty);
505void tty_unlock(struct tty_struct *tty);
506void tty_lock_slave(struct tty_struct *tty);
507void tty_unlock_slave(struct tty_struct *tty);
508void tty_set_lock_subclass(struct tty_struct *tty);
509
510#endif