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 #include <linux/android_kabi.h>
19
20
21 /*
22 * (Note: the *_driver.minor_start values 1, 64, 128, 192 are
23 * hardcoded at present.)
24 */
25 #define NR_UNIX98_PTY_DEFAULT 4096 /* Default maximum for Unix98 ptys */
26 #define NR_UNIX98_PTY_RESERVE 1024 /* Default reserve for main devpts */
27 #define NR_UNIX98_PTY_MAX (1 << MINORBITS) /* Absolute limit */
28
29 /*
30 * This character is the same as _POSIX_VDISABLE: it cannot be used as
31 * a c_cc[] character, but indicates that a particular special character
32 * isn't in use (eg VINTR has no character etc)
33 */
34 #define __DISABLED_CHAR '\0'
35
36 #define INTR_CHAR(tty) ((tty)->termios.c_cc[VINTR])
37 #define QUIT_CHAR(tty) ((tty)->termios.c_cc[VQUIT])
38 #define ERASE_CHAR(tty) ((tty)->termios.c_cc[VERASE])
39 #define KILL_CHAR(tty) ((tty)->termios.c_cc[VKILL])
40 #define EOF_CHAR(tty) ((tty)->termios.c_cc[VEOF])
41 #define TIME_CHAR(tty) ((tty)->termios.c_cc[VTIME])
42 #define MIN_CHAR(tty) ((tty)->termios.c_cc[VMIN])
43 #define SWTC_CHAR(tty) ((tty)->termios.c_cc[VSWTC])
44 #define START_CHAR(tty) ((tty)->termios.c_cc[VSTART])
45 #define STOP_CHAR(tty) ((tty)->termios.c_cc[VSTOP])
46 #define SUSP_CHAR(tty) ((tty)->termios.c_cc[VSUSP])
47 #define EOL_CHAR(tty) ((tty)->termios.c_cc[VEOL])
48 #define REPRINT_CHAR(tty) ((tty)->termios.c_cc[VREPRINT])
49 #define DISCARD_CHAR(tty) ((tty)->termios.c_cc[VDISCARD])
50 #define WERASE_CHAR(tty) ((tty)->termios.c_cc[VWERASE])
51 #define LNEXT_CHAR(tty) ((tty)->termios.c_cc[VLNEXT])
52 #define EOL2_CHAR(tty) ((tty)->termios.c_cc[VEOL2])
53
54 #define _I_FLAG(tty, f) ((tty)->termios.c_iflag & (f))
55 #define _O_FLAG(tty, f) ((tty)->termios.c_oflag & (f))
56 #define _C_FLAG(tty, f) ((tty)->termios.c_cflag & (f))
57 #define _L_FLAG(tty, f) ((tty)->termios.c_lflag & (f))
58
59 #define I_IGNBRK(tty) _I_FLAG((tty), IGNBRK)
60 #define I_BRKINT(tty) _I_FLAG((tty), BRKINT)
61 #define I_IGNPAR(tty) _I_FLAG((tty), IGNPAR)
62 #define I_PARMRK(tty) _I_FLAG((tty), PARMRK)
63 #define I_INPCK(tty) _I_FLAG((tty), INPCK)
64 #define I_ISTRIP(tty) _I_FLAG((tty), ISTRIP)
65 #define I_INLCR(tty) _I_FLAG((tty), INLCR)
66 #define I_IGNCR(tty) _I_FLAG((tty), IGNCR)
67 #define I_ICRNL(tty) _I_FLAG((tty), ICRNL)
68 #define I_IUCLC(tty) _I_FLAG((tty), IUCLC)
69 #define I_IXON(tty) _I_FLAG((tty), IXON)
70 #define I_IXANY(tty) _I_FLAG((tty), IXANY)
71 #define I_IXOFF(tty) _I_FLAG((tty), IXOFF)
72 #define I_IMAXBEL(tty) _I_FLAG((tty), IMAXBEL)
73 #define I_IUTF8(tty) _I_FLAG((tty), IUTF8)
74
75 #define O_OPOST(tty) _O_FLAG((tty), OPOST)
76 #define O_OLCUC(tty) _O_FLAG((tty), OLCUC)
77 #define O_ONLCR(tty) _O_FLAG((tty), ONLCR)
78 #define O_OCRNL(tty) _O_FLAG((tty), OCRNL)
79 #define O_ONOCR(tty) _O_FLAG((tty), ONOCR)
80 #define O_ONLRET(tty) _O_FLAG((tty), ONLRET)
81 #define O_OFILL(tty) _O_FLAG((tty), OFILL)
82 #define O_OFDEL(tty) _O_FLAG((tty), OFDEL)
83 #define O_NLDLY(tty) _O_FLAG((tty), NLDLY)
84 #define O_CRDLY(tty) _O_FLAG((tty), CRDLY)
85 #define O_TABDLY(tty) _O_FLAG((tty), TABDLY)
86 #define O_BSDLY(tty) _O_FLAG((tty), BSDLY)
87 #define O_VTDLY(tty) _O_FLAG((tty), VTDLY)
88 #define O_FFDLY(tty) _O_FLAG((tty), FFDLY)
89
90 #define C_BAUD(tty) _C_FLAG((tty), CBAUD)
91 #define C_CSIZE(tty) _C_FLAG((tty), CSIZE)
92 #define C_CSTOPB(tty) _C_FLAG((tty), CSTOPB)
93 #define C_CREAD(tty) _C_FLAG((tty), CREAD)
94 #define C_PARENB(tty) _C_FLAG((tty), PARENB)
95 #define C_PARODD(tty) _C_FLAG((tty), PARODD)
96 #define C_HUPCL(tty) _C_FLAG((tty), HUPCL)
97 #define C_CLOCAL(tty) _C_FLAG((tty), CLOCAL)
98 #define C_CIBAUD(tty) _C_FLAG((tty), CIBAUD)
99 #define C_CRTSCTS(tty) _C_FLAG((tty), CRTSCTS)
100 #define C_CMSPAR(tty) _C_FLAG((tty), CMSPAR)
101
102 #define L_ISIG(tty) _L_FLAG((tty), ISIG)
103 #define L_ICANON(tty) _L_FLAG((tty), ICANON)
104 #define L_XCASE(tty) _L_FLAG((tty), XCASE)
105 #define L_ECHO(tty) _L_FLAG((tty), ECHO)
106 #define L_ECHOE(tty) _L_FLAG((tty), ECHOE)
107 #define L_ECHOK(tty) _L_FLAG((tty), ECHOK)
108 #define L_ECHONL(tty) _L_FLAG((tty), ECHONL)
109 #define L_NOFLSH(tty) _L_FLAG((tty), NOFLSH)
110 #define L_TOSTOP(tty) _L_FLAG((tty), TOSTOP)
111 #define L_ECHOCTL(tty) _L_FLAG((tty), ECHOCTL)
112 #define L_ECHOPRT(tty) _L_FLAG((tty), ECHOPRT)
113 #define L_ECHOKE(tty) _L_FLAG((tty), ECHOKE)
114 #define L_FLUSHO(tty) _L_FLAG((tty), FLUSHO)
115 #define L_PENDIN(tty) _L_FLAG((tty), PENDIN)
116 #define L_IEXTEN(tty) _L_FLAG((tty), IEXTEN)
117 #define L_EXTPROC(tty) _L_FLAG((tty), EXTPROC)
118
119 struct device;
120 struct signal_struct;
121 struct tty_operations;
122
123 /**
124 * struct tty_struct - state associated with a tty while open
125 *
126 * @flow.lock: lock for flow members
127 * @flow.stopped: tty stopped/started by tty_stop/tty_start
128 * @flow.tco_stopped: tty stopped/started by TCOOFF/TCOON ioctls (it has
129 * precedense over @flow.stopped)
130 * @flow.unused: alignment for Alpha, so that no members other than @flow.* are
131 * modified by the same 64b word store. The @flow's __aligned is
132 * there for the very same reason.
133 * @ctrl.lock: lock for ctrl members
134 * @ctrl.pgrp: process group of this tty (setpgrp(2))
135 * @ctrl.session: session of this tty (setsid(2)). Writes are protected by both
136 * @ctrl.lock and legacy mutex, readers must use at least one of
137 * them.
138 * @ctrl.pktstatus: packet mode status (bitwise OR of TIOCPKT_* constants)
139 * @ctrl.packet: packet mode enabled
140 *
141 * All of the state associated with a tty while the tty is open. Persistent
142 * storage for tty devices is referenced here as @port in struct tty_port.
143 */
144 struct tty_struct {
145 int magic;
146 struct kref kref;
147 struct device *dev; /* class device or NULL (e.g. ptys, serdev) */
148 struct tty_driver *driver;
149 const struct tty_operations *ops;
150 int index;
151
152 /* Protects ldisc changes: Lock tty not pty */
153 struct ld_semaphore ldisc_sem;
154 struct tty_ldisc *ldisc;
155
156 struct mutex atomic_write_lock;
157 struct mutex legacy_mutex;
158 struct mutex throttle_mutex;
159 struct rw_semaphore termios_rwsem;
160 struct mutex winsize_mutex;
161 /* Termios values are protected by the termios rwsem */
162 struct ktermios termios, termios_locked;
163 char name[64];
164 unsigned long flags;
165 int count;
166 struct winsize winsize; /* winsize_mutex */
167
168 struct {
169 spinlock_t lock;
170 bool stopped;
171 bool tco_stopped;
172 unsigned long unused[0];
173 } __aligned(sizeof(unsigned long)) flow;
174
175 struct {
176 spinlock_t lock;
177 struct pid *pgrp;
178 struct pid *session;
179 unsigned char pktstatus;
180 bool packet;
181 unsigned long unused[0];
182 } __aligned(sizeof(unsigned long)) ctrl;
183
184 int hw_stopped;
185 unsigned int receive_room; /* Bytes free for queue */
186 int flow_change;
187
188 struct tty_struct *link;
189 struct fasync_struct *fasync;
190 wait_queue_head_t write_wait;
191 wait_queue_head_t read_wait;
192 struct work_struct hangup_work;
193 void *disc_data;
194 void *driver_data;
195 spinlock_t files_lock; /* protects tty_files list */
196 struct list_head tty_files;
197
198 #define N_TTY_BUF_SIZE 4096
199
200 int closing;
201 unsigned char *write_buf;
202 int write_cnt;
203 /* If the tty has a pending do_SAK, queue it here - akpm */
204 struct work_struct SAK_work;
205 struct tty_port *port;
206
207 ANDROID_KABI_RESERVE(1);
208 ANDROID_KABI_RESERVE(2);
209 } __randomize_layout;
210
211 /* Each of a tty's open files has private_data pointing to tty_file_private */
212 struct tty_file_private {
213 struct tty_struct *tty;
214 struct file *file;
215 struct list_head list;
216 };
217
218 /* tty magic number */
219 #define TTY_MAGIC 0x5401
220
221 /*
222 * These bits are used in the flags field of the tty structure.
223 *
224 * So that interrupts won't be able to mess up the queues,
225 * copy_to_cooked must be atomic with respect to itself, as must
226 * tty->write. Thus, you must use the inline functions set_bit() and
227 * clear_bit() to make things atomic.
228 */
229 #define TTY_THROTTLED 0 /* Call unthrottle() at threshold min */
230 #define TTY_IO_ERROR 1 /* Cause an I/O error (may be no ldisc too) */
231 #define TTY_OTHER_CLOSED 2 /* Other side (if any) has closed */
232 #define TTY_EXCLUSIVE 3 /* Exclusive open mode */
233 #define TTY_DO_WRITE_WAKEUP 5 /* Call write_wakeup after queuing new */
234 #define TTY_LDISC_OPEN 11 /* Line discipline is open */
235 #define TTY_PTY_LOCK 16 /* pty private */
236 #define TTY_NO_WRITE_SPLIT 17 /* Preserve write boundaries to driver */
237 #define TTY_HUPPED 18 /* Post driver->hangup() */
238 #define TTY_HUPPING 19 /* Hangup in progress */
239 #define TTY_LDISC_CHANGING 20 /* Change pending - non-block IO */
240 #define TTY_LDISC_HALTED 22 /* Line discipline is halted */
241
tty_io_nonblock(struct tty_struct * tty,struct file * file)242 static inline bool tty_io_nonblock(struct tty_struct *tty, struct file *file)
243 {
244 return file->f_flags & O_NONBLOCK ||
245 test_bit(TTY_LDISC_CHANGING, &tty->flags);
246 }
247
tty_io_error(struct tty_struct * tty)248 static inline bool tty_io_error(struct tty_struct *tty)
249 {
250 return test_bit(TTY_IO_ERROR, &tty->flags);
251 }
252
tty_throttled(struct tty_struct * tty)253 static inline bool tty_throttled(struct tty_struct *tty)
254 {
255 return test_bit(TTY_THROTTLED, &tty->flags);
256 }
257
258 #ifdef CONFIG_TTY
259 extern void tty_kref_put(struct tty_struct *tty);
260 extern struct pid *tty_get_pgrp(struct tty_struct *tty);
261 extern void tty_vhangup_self(void);
262 extern void disassociate_ctty(int priv);
263 extern dev_t tty_devnum(struct tty_struct *tty);
264 extern void proc_clear_tty(struct task_struct *p);
265 extern struct tty_struct *get_current_tty(void);
266 /* tty_io.c */
267 extern int __init tty_init(void);
268 extern const char *tty_name(const struct tty_struct *tty);
269 extern struct tty_struct *tty_kopen_exclusive(dev_t device);
270 extern struct tty_struct *tty_kopen_shared(dev_t device);
271 extern void tty_kclose(struct tty_struct *tty);
272 extern int tty_dev_name_to_number(const char *name, dev_t *number);
273 #else
tty_kref_put(struct tty_struct * tty)274 static inline void tty_kref_put(struct tty_struct *tty)
275 { }
tty_get_pgrp(struct tty_struct * tty)276 static inline struct pid *tty_get_pgrp(struct tty_struct *tty)
277 { return NULL; }
tty_vhangup_self(void)278 static inline void tty_vhangup_self(void)
279 { }
disassociate_ctty(int priv)280 static inline void disassociate_ctty(int priv)
281 { }
tty_devnum(struct tty_struct * tty)282 static inline dev_t tty_devnum(struct tty_struct *tty)
283 { return 0; }
proc_clear_tty(struct task_struct * p)284 static inline void proc_clear_tty(struct task_struct *p)
285 { }
get_current_tty(void)286 static inline struct tty_struct *get_current_tty(void)
287 { return NULL; }
288 /* tty_io.c */
tty_init(void)289 static inline int __init tty_init(void)
290 { return 0; }
tty_name(const struct tty_struct * tty)291 static inline const char *tty_name(const struct tty_struct *tty)
292 { return "(none)"; }
tty_kopen_exclusive(dev_t device)293 static inline struct tty_struct *tty_kopen_exclusive(dev_t device)
294 { return ERR_PTR(-ENODEV); }
tty_kclose(struct tty_struct * tty)295 static inline void tty_kclose(struct tty_struct *tty)
296 { }
tty_dev_name_to_number(const char * name,dev_t * number)297 static inline int tty_dev_name_to_number(const char *name, dev_t *number)
298 { return -ENOTSUPP; }
299 #endif
300
301 extern struct ktermios tty_std_termios;
302
303 extern int vcs_init(void);
304
305 extern struct class *tty_class;
306
307 /**
308 * tty_kref_get - get a tty reference
309 * @tty: tty device
310 *
311 * Return a new reference to a tty object. The caller must hold
312 * sufficient locks/counts to ensure that their existing reference cannot
313 * go away
314 */
315
tty_kref_get(struct tty_struct * tty)316 static inline struct tty_struct *tty_kref_get(struct tty_struct *tty)
317 {
318 if (tty)
319 kref_get(&tty->kref);
320 return tty;
321 }
322
323 extern const char *tty_driver_name(const struct tty_struct *tty);
324 extern void tty_wait_until_sent(struct tty_struct *tty, long timeout);
325 extern void stop_tty(struct tty_struct *tty);
326 extern void start_tty(struct tty_struct *tty);
327 extern void tty_write_message(struct tty_struct *tty, char *msg);
328 extern int tty_send_xchar(struct tty_struct *tty, char ch);
329 extern int tty_put_char(struct tty_struct *tty, unsigned char c);
330 extern unsigned int tty_chars_in_buffer(struct tty_struct *tty);
331 extern unsigned int tty_write_room(struct tty_struct *tty);
332 extern void tty_driver_flush_buffer(struct tty_struct *tty);
333 extern void tty_unthrottle(struct tty_struct *tty);
334 extern int tty_throttle_safe(struct tty_struct *tty);
335 extern int tty_unthrottle_safe(struct tty_struct *tty);
336 extern int tty_do_resize(struct tty_struct *tty, struct winsize *ws);
337 extern int tty_get_icount(struct tty_struct *tty,
338 struct serial_icounter_struct *icount);
339 extern int is_current_pgrp_orphaned(void);
340 extern void tty_hangup(struct tty_struct *tty);
341 extern void tty_vhangup(struct tty_struct *tty);
342 extern int tty_hung_up_p(struct file *filp);
343 extern void do_SAK(struct tty_struct *tty);
344 extern void __do_SAK(struct tty_struct *tty);
345 extern void no_tty(void);
346 extern speed_t tty_termios_baud_rate(struct ktermios *termios);
347 extern void tty_termios_encode_baud_rate(struct ktermios *termios,
348 speed_t ibaud, speed_t obaud);
349 extern void tty_encode_baud_rate(struct tty_struct *tty,
350 speed_t ibaud, speed_t obaud);
351
352 /**
353 * tty_get_baud_rate - get tty bit rates
354 * @tty: tty to query
355 *
356 * Returns the baud rate as an integer for this terminal. The
357 * termios lock must be held by the caller and the terminal bit
358 * flags may be updated.
359 *
360 * Locking: none
361 */
tty_get_baud_rate(struct tty_struct * tty)362 static inline speed_t tty_get_baud_rate(struct tty_struct *tty)
363 {
364 return tty_termios_baud_rate(&tty->termios);
365 }
366
367 unsigned char tty_get_char_size(unsigned int cflag);
368 unsigned char tty_get_frame_size(unsigned int cflag);
369
370 extern void tty_termios_copy_hw(struct ktermios *new, struct ktermios *old);
371 extern int tty_termios_hw_change(const struct ktermios *a, const struct ktermios *b);
372 extern int tty_set_termios(struct tty_struct *tty, struct ktermios *kt);
373
374 extern void tty_wakeup(struct tty_struct *tty);
375
376 extern int tty_mode_ioctl(struct tty_struct *tty, struct file *file,
377 unsigned int cmd, unsigned long arg);
378 extern int tty_perform_flush(struct tty_struct *tty, unsigned long arg);
379 extern struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx);
380 extern void tty_release_struct(struct tty_struct *tty, int idx);
381 extern void tty_init_termios(struct tty_struct *tty);
382 extern void tty_save_termios(struct tty_struct *tty);
383 extern int tty_standard_install(struct tty_driver *driver,
384 struct tty_struct *tty);
385
386 extern struct mutex tty_mutex;
387
388 /* n_tty.c */
389 extern void n_tty_inherit_ops(struct tty_ldisc_ops *ops);
390 #ifdef CONFIG_TTY
391 extern void __init n_tty_init(void);
392 #else
n_tty_init(void)393 static inline void n_tty_init(void) { }
394 #endif
395
396 /* tty_audit.c */
397 #ifdef CONFIG_AUDIT
398 extern void tty_audit_exit(void);
399 extern void tty_audit_fork(struct signal_struct *sig);
400 extern int tty_audit_push(void);
401 #else
tty_audit_exit(void)402 static inline void tty_audit_exit(void)
403 {
404 }
tty_audit_fork(struct signal_struct * sig)405 static inline void tty_audit_fork(struct signal_struct *sig)
406 {
407 }
tty_audit_push(void)408 static inline int tty_audit_push(void)
409 {
410 return 0;
411 }
412 #endif
413
414 /* tty_ioctl.c */
415 extern int n_tty_ioctl_helper(struct tty_struct *tty, struct file *file,
416 unsigned int cmd, unsigned long arg);
417
418 /* vt.c */
419
420 extern int vt_ioctl(struct tty_struct *tty,
421 unsigned int cmd, unsigned long arg);
422
423 extern long vt_compat_ioctl(struct tty_struct *tty,
424 unsigned int cmd, unsigned long arg);
425
426 /* tty_mutex.c */
427 /* functions for preparation of BKL removal */
428 extern void tty_lock(struct tty_struct *tty);
429 extern int tty_lock_interruptible(struct tty_struct *tty);
430 extern void tty_unlock(struct tty_struct *tty);
431 extern void tty_lock_slave(struct tty_struct *tty);
432 extern void tty_unlock_slave(struct tty_struct *tty);
433 extern void tty_set_lock_subclass(struct tty_struct *tty);
434
435 #endif
436