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 extern void tty_kref_put(struct tty_struct *tty);
256 extern struct pid *tty_get_pgrp(struct tty_struct *tty);
257 extern void tty_vhangup_self(void);
258 extern void disassociate_ctty(int priv);
259 extern dev_t tty_devnum(struct tty_struct *tty);
260 extern void proc_clear_tty(struct task_struct *p);
261 extern struct tty_struct *get_current_tty(void);
262 /* tty_io.c */
263 extern int __init tty_init(void);
264 extern const char *tty_name(const struct tty_struct *tty);
265 extern struct tty_struct *tty_kopen_exclusive(dev_t device);
266 extern struct tty_struct *tty_kopen_shared(dev_t device);
267 extern void tty_kclose(struct tty_struct *tty);
268 extern 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 extern 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 extern const char *tty_driver_name(const struct tty_struct *tty);
320 extern void tty_wait_until_sent(struct tty_struct *tty, long timeout);
321 extern void stop_tty(struct tty_struct *tty);
322 extern void start_tty(struct tty_struct *tty);
323 extern void tty_write_message(struct tty_struct *tty, char *msg);
324 extern int tty_send_xchar(struct tty_struct *tty, char ch);
325 extern int tty_put_char(struct tty_struct *tty, unsigned char c);
326 extern unsigned int tty_chars_in_buffer(struct tty_struct *tty);
327 extern unsigned int tty_write_room(struct tty_struct *tty);
328 extern void tty_driver_flush_buffer(struct tty_struct *tty);
329 extern void tty_unthrottle(struct tty_struct *tty);
330 extern int tty_throttle_safe(struct tty_struct *tty);
331 extern int tty_unthrottle_safe(struct tty_struct *tty);
332 extern int tty_do_resize(struct tty_struct *tty, struct winsize *ws);
333 extern int tty_get_icount(struct tty_struct *tty,
334 struct serial_icounter_struct *icount);
335 extern int is_current_pgrp_orphaned(void);
336 extern void tty_hangup(struct tty_struct *tty);
337 extern void tty_vhangup(struct tty_struct *tty);
338 extern int tty_hung_up_p(struct file *filp);
339 extern void do_SAK(struct tty_struct *tty);
340 extern void __do_SAK(struct tty_struct *tty);
341 extern void no_tty(void);
342 extern speed_t tty_termios_baud_rate(struct ktermios *termios);
343 extern void tty_termios_encode_baud_rate(struct ktermios *termios,
344 speed_t ibaud, speed_t obaud);
345 extern void tty_encode_baud_rate(struct tty_struct *tty,
346 speed_t ibaud, 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 extern void tty_termios_copy_hw(struct ktermios *new, struct ktermios *old);
367 extern int tty_termios_hw_change(const struct ktermios *a, const struct ktermios *b);
368 extern int tty_set_termios(struct tty_struct *tty, struct ktermios *kt);
369
370 extern void tty_wakeup(struct tty_struct *tty);
371
372 extern int tty_mode_ioctl(struct tty_struct *tty, struct file *file,
373 unsigned int cmd, unsigned long arg);
374 extern int tty_perform_flush(struct tty_struct *tty, unsigned long arg);
375 extern struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx);
376 extern void tty_release_struct(struct tty_struct *tty, int idx);
377 extern void tty_init_termios(struct tty_struct *tty);
378 extern void tty_save_termios(struct tty_struct *tty);
379 extern int tty_standard_install(struct tty_driver *driver,
380 struct tty_struct *tty);
381
382 extern struct mutex tty_mutex;
383
384 /* n_tty.c */
385 extern void n_tty_inherit_ops(struct tty_ldisc_ops *ops);
386 #ifdef CONFIG_TTY
387 extern void __init n_tty_init(void);
388 #else
n_tty_init(void)389 static inline void n_tty_init(void) { }
390 #endif
391
392 /* tty_audit.c */
393 #ifdef CONFIG_AUDIT
394 extern void tty_audit_exit(void);
395 extern void tty_audit_fork(struct signal_struct *sig);
396 extern int tty_audit_push(void);
397 #else
tty_audit_exit(void)398 static inline void tty_audit_exit(void)
399 {
400 }
tty_audit_fork(struct signal_struct * sig)401 static inline void tty_audit_fork(struct signal_struct *sig)
402 {
403 }
tty_audit_push(void)404 static inline int tty_audit_push(void)
405 {
406 return 0;
407 }
408 #endif
409
410 /* tty_ioctl.c */
411 extern int n_tty_ioctl_helper(struct tty_struct *tty, struct file *file,
412 unsigned int cmd, unsigned long arg);
413
414 /* vt.c */
415
416 extern int vt_ioctl(struct tty_struct *tty,
417 unsigned int cmd, unsigned long arg);
418
419 extern long vt_compat_ioctl(struct tty_struct *tty,
420 unsigned int cmd, unsigned long arg);
421
422 /* tty_mutex.c */
423 /* functions for preparation of BKL removal */
424 extern void tty_lock(struct tty_struct *tty);
425 extern int tty_lock_interruptible(struct tty_struct *tty);
426 extern void tty_unlock(struct tty_struct *tty);
427 extern void tty_lock_slave(struct tty_struct *tty);
428 extern void tty_unlock_slave(struct tty_struct *tty);
429 extern void tty_set_lock_subclass(struct tty_struct *tty);
430
431 #endif
432
