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 * @kref: reference counting by tty_kref_get() and tty_kref_put(), reaching zero 126 * frees the structure 127 * @dev: class device or %NULL (e.g. ptys, serdev) 128 * @driver: &struct tty_driver operating this tty 129 * @ops: &struct tty_operations of @driver for this tty (open, close, etc.) 130 * @index: index of this tty (e.g. to construct @name like tty12) 131 * @ldisc_sem: protects line discipline changes (@ldisc) -- lock tty not pty 132 * @ldisc: the current line discipline for this tty (n_tty by default) 133 * @atomic_write_lock: protects against concurrent writers, i.e. locks 134 * @write_cnt, @write_buf and similar 135 * @legacy_mutex: leftover from history (BKL -> BTM -> @legacy_mutex), 136 * protecting several operations on this tty 137 * @throttle_mutex: protects against concurrent tty_throttle_safe() and 138 * tty_unthrottle_safe() (but not tty_unthrottle()) 139 * @termios_rwsem: protects @termios and @termios_locked 140 * @winsize_mutex: protects @winsize 141 * @termios: termios for the current tty, copied from/to @driver.termios 142 * @termios_locked: locked termios (by %TIOCGLCKTRMIOS and %TIOCSLCKTRMIOS 143 * ioctls) 144 * @name: name of the tty constructed by tty_line_name() (e.g. ttyS3) 145 * @flags: bitwise OR of %TTY_THROTTLED, %TTY_IO_ERROR, ... 146 * @count: count of open processes, reaching zero cancels all the work for 147 * this tty and drops a @kref too (but does not free this tty) 148 * @winsize: size of the terminal "window" (cf. @winsize_mutex) 149 * @flow: flow settings grouped together, see also @flow.unused 150 * @flow.lock: lock for @flow members 151 * @flow.stopped: tty stopped/started by stop_tty()/start_tty() 152 * @flow.tco_stopped: tty stopped/started by %TCOOFF/%TCOON ioctls (it has 153 * precedence over @flow.stopped) 154 * @flow.unused: alignment for Alpha, so that no members other than @flow.* are 155 * modified by the same 64b word store. The @flow's __aligned is 156 * there for the very same reason. 157 * @ctrl: control settings grouped together, see also @ctrl.unused 158 * @ctrl.lock: lock for @ctrl members 159 * @ctrl.pgrp: process group of this tty (setpgrp(2)) 160 * @ctrl.session: session of this tty (setsid(2)). Writes are protected by both 161 * @ctrl.lock and @legacy_mutex, readers must use at least one of 162 * them. 163 * @ctrl.pktstatus: packet mode status (bitwise OR of %TIOCPKT_ constants) 164 * @ctrl.packet: packet mode enabled 165 * @ctrl.unused: alignment for Alpha, see @flow.unused for explanation 166 * @hw_stopped: not controlled by the tty layer, under @driver's control for CTS 167 * handling 168 * @receive_room: bytes permitted to feed to @ldisc without any being lost 169 * @flow_change: controls behavior of throttling, see tty_throttle_safe() and 170 * tty_unthrottle_safe() 171 * @link: link to another pty (master -> slave and vice versa) 172 * @fasync: state for %O_ASYNC (for %SIGIO); managed by fasync_helper() 173 * @write_wait: concurrent writers are waiting in this queue until they are 174 * allowed to write 175 * @read_wait: readers wait for data in this queue 176 * @hangup_work: normally a work to perform a hangup (do_tty_hangup()); while 177 * freeing the tty, (re)used to release_one_tty() 178 * @disc_data: pointer to @ldisc's private data (e.g. to &struct n_tty_data) 179 * @driver_data: pointer to @driver's private data (e.g. &struct uart_state) 180 * @files_lock: protects @tty_files list 181 * @tty_files: list of (re)openers of this tty (i.e. linked &struct 182 * tty_file_private) 183 * @closing: when set during close, n_tty processes only START & STOP chars 184 * @write_buf: temporary buffer used during tty_write() to copy user data to 185 * @write_cnt: count of bytes written in tty_write() to @write_buf 186 * @SAK_work: if the tty has a pending do_SAK, it is queued here 187 * @port: persistent storage for this device (i.e. &struct tty_port) 188 * 189 * All of the state associated with a tty while the tty is open. Persistent 190 * storage for tty devices is referenced here as @port and is documented in 191 * &struct tty_port. 192 */ 193 struct tty_struct { 194 struct kref kref; 195 struct device *dev; 196 struct tty_driver *driver; 197 const struct tty_operations *ops; 198 int index; 199 200 struct ld_semaphore ldisc_sem; 201 struct tty_ldisc *ldisc; 202 203 struct mutex atomic_write_lock; 204 struct mutex legacy_mutex; 205 struct mutex throttle_mutex; 206 struct rw_semaphore termios_rwsem; 207 struct mutex winsize_mutex; 208 struct ktermios termios, termios_locked; 209 char name[64]; 210 unsigned long flags; 211 int count; 212 struct winsize winsize; 213 214 struct { 215 spinlock_t lock; 216 bool stopped; 217 bool tco_stopped; 218 unsigned long unused[0]; 219 } __aligned(sizeof(unsigned long)) flow; 220 221 struct { 222 spinlock_t lock; 223 struct pid *pgrp; 224 struct pid *session; 225 unsigned char pktstatus; 226 bool packet; 227 unsigned long unused[0]; 228 } __aligned(sizeof(unsigned long)) ctrl; 229 230 int hw_stopped; 231 unsigned int receive_room; 232 int flow_change; 233 234 struct tty_struct *link; 235 struct fasync_struct *fasync; 236 wait_queue_head_t write_wait; 237 wait_queue_head_t read_wait; 238 struct work_struct hangup_work; 239 void *disc_data; 240 void *driver_data; 241 spinlock_t files_lock; 242 struct list_head tty_files; 243 244 #define N_TTY_BUF_SIZE 4096 245 246 int closing; 247 unsigned char *write_buf; 248 int write_cnt; 249 struct work_struct SAK_work; 250 struct tty_port *port; 251 } __randomize_layout; 252 253 /* Each of a tty's open files has private_data pointing to tty_file_private */ 254 struct tty_file_private { 255 struct tty_struct *tty; 256 struct file *file; 257 struct list_head list; 258 }; 259 260 /** 261 * DOC: TTY Struct Flags 262 * 263 * These bits are used in the :c:member:`tty_struct.flags` field. 264 * 265 * So that interrupts won't be able to mess up the queues, 266 * copy_to_cooked must be atomic with respect to itself, as must 267 * tty->write. Thus, you must use the inline functions set_bit() and 268 * clear_bit() to make things atomic. 269 * 270 * TTY_THROTTLED 271 * Driver input is throttled. The ldisc should call 272 * :c:member:`tty_driver.unthrottle()` in order to resume reception when 273 * it is ready to process more data (at threshold min). 274 * 275 * TTY_IO_ERROR 276 * If set, causes all subsequent userspace read/write calls on the tty to 277 * fail, returning -%EIO. (May be no ldisc too.) 278 * 279 * TTY_OTHER_CLOSED 280 * Device is a pty and the other side has closed. 281 * 282 * TTY_EXCLUSIVE 283 * Exclusive open mode (a single opener). 284 * 285 * TTY_DO_WRITE_WAKEUP 286 * If set, causes the driver to call the 287 * :c:member:`tty_ldisc_ops.write_wakeup()` method in order to resume 288 * transmission when it can accept more data to transmit. 289 * 290 * TTY_LDISC_OPEN 291 * Indicates that a line discipline is open. For debugging purposes only. 292 * 293 * TTY_PTY_LOCK 294 * A flag private to pty code to implement %TIOCSPTLCK/%TIOCGPTLCK logic. 295 * 296 * TTY_NO_WRITE_SPLIT 297 * Prevent driver from splitting up writes into smaller chunks (preserve 298 * write boundaries to driver). 299 * 300 * TTY_HUPPED 301 * The TTY was hung up. This is set post :c:member:`tty_driver.hangup()`. 302 * 303 * TTY_HUPPING 304 * The TTY is in the process of hanging up to abort potential readers. 305 * 306 * TTY_LDISC_CHANGING 307 * Line discipline for this TTY is being changed. I/O should not block 308 * when this is set. Use tty_io_nonblock() to check. 309 * 310 * TTY_LDISC_HALTED 311 * Line discipline for this TTY was stopped. No work should be queued to 312 * this ldisc. 313 */ 314 #define TTY_THROTTLED 0 315 #define TTY_IO_ERROR 1 316 #define TTY_OTHER_CLOSED 2 317 #define TTY_EXCLUSIVE 3 318 #define TTY_DO_WRITE_WAKEUP 5 319 #define TTY_LDISC_OPEN 11 320 #define TTY_PTY_LOCK 16 321 #define TTY_NO_WRITE_SPLIT 17 322 #define TTY_HUPPED 18 323 #define TTY_HUPPING 19 324 #define TTY_LDISC_CHANGING 20 325 #define TTY_LDISC_HALTED 22 326 327 static inline bool tty_io_nonblock(struct tty_struct *tty, struct file *file) 328 { 329 return file->f_flags & O_NONBLOCK || 330 test_bit(TTY_LDISC_CHANGING, &tty->flags); 331 } 332 333 static inline bool tty_io_error(struct tty_struct *tty) 334 { 335 return test_bit(TTY_IO_ERROR, &tty->flags); 336 } 337 338 static inline bool tty_throttled(struct tty_struct *tty) 339 { 340 return test_bit(TTY_THROTTLED, &tty->flags); 341 } 342 343 #ifdef CONFIG_TTY 344 void tty_kref_put(struct tty_struct *tty); 345 struct pid *tty_get_pgrp(struct tty_struct *tty); 346 void tty_vhangup_self(void); 347 void disassociate_ctty(int priv); 348 dev_t tty_devnum(struct tty_struct *tty); 349 void proc_clear_tty(struct task_struct *p); 350 struct tty_struct *get_current_tty(void); 351 /* tty_io.c */ 352 int __init tty_init(void); 353 const char *tty_name(const struct tty_struct *tty); 354 struct tty_struct *tty_kopen_exclusive(dev_t device); 355 struct tty_struct *tty_kopen_shared(dev_t device); 356 void tty_kclose(struct tty_struct *tty); 357 int tty_dev_name_to_number(const char *name, dev_t *number); 358 #else 359 static inline void tty_kref_put(struct tty_struct *tty) 360 { } 361 static inline struct pid *tty_get_pgrp(struct tty_struct *tty) 362 { return NULL; } 363 static inline void tty_vhangup_self(void) 364 { } 365 static inline void disassociate_ctty(int priv) 366 { } 367 static inline dev_t tty_devnum(struct tty_struct *tty) 368 { return 0; } 369 static inline void proc_clear_tty(struct task_struct *p) 370 { } 371 static inline struct tty_struct *get_current_tty(void) 372 { return NULL; } 373 /* tty_io.c */ 374 static inline int __init tty_init(void) 375 { return 0; } 376 static inline const char *tty_name(const struct tty_struct *tty) 377 { return "(none)"; } 378 static inline struct tty_struct *tty_kopen_exclusive(dev_t device) 379 { return ERR_PTR(-ENODEV); } 380 static inline void tty_kclose(struct tty_struct *tty) 381 { } 382 static inline int tty_dev_name_to_number(const char *name, dev_t *number) 383 { return -ENOTSUPP; } 384 #endif 385 386 extern struct ktermios tty_std_termios; 387 388 int vcs_init(void); 389 390 extern struct class *tty_class; 391 392 /** 393 * tty_kref_get - get a tty reference 394 * @tty: tty device 395 * 396 * Return a new reference to a tty object. The caller must hold 397 * sufficient locks/counts to ensure that their existing reference cannot 398 * go away 399 */ 400 401 static inline struct tty_struct *tty_kref_get(struct tty_struct *tty) 402 { 403 if (tty) 404 kref_get(&tty->kref); 405 return tty; 406 } 407 408 const char *tty_driver_name(const struct tty_struct *tty); 409 void tty_wait_until_sent(struct tty_struct *tty, long timeout); 410 void stop_tty(struct tty_struct *tty); 411 void start_tty(struct tty_struct *tty); 412 void tty_write_message(struct tty_struct *tty, char *msg); 413 int tty_send_xchar(struct tty_struct *tty, char ch); 414 int tty_put_char(struct tty_struct *tty, unsigned char c); 415 unsigned int tty_chars_in_buffer(struct tty_struct *tty); 416 unsigned int tty_write_room(struct tty_struct *tty); 417 void tty_driver_flush_buffer(struct tty_struct *tty); 418 void tty_unthrottle(struct tty_struct *tty); 419 int tty_throttle_safe(struct tty_struct *tty); 420 int tty_unthrottle_safe(struct tty_struct *tty); 421 int tty_do_resize(struct tty_struct *tty, struct winsize *ws); 422 int tty_get_icount(struct tty_struct *tty, 423 struct serial_icounter_struct *icount); 424 int is_current_pgrp_orphaned(void); 425 void tty_hangup(struct tty_struct *tty); 426 void tty_vhangup(struct tty_struct *tty); 427 int tty_hung_up_p(struct file *filp); 428 void do_SAK(struct tty_struct *tty); 429 void __do_SAK(struct tty_struct *tty); 430 void no_tty(void); 431 speed_t tty_termios_baud_rate(const struct ktermios *termios); 432 void tty_termios_encode_baud_rate(struct ktermios *termios, speed_t ibaud, 433 speed_t obaud); 434 void tty_encode_baud_rate(struct tty_struct *tty, speed_t ibaud, 435 speed_t obaud); 436 437 /** 438 * tty_get_baud_rate - get tty bit rates 439 * @tty: tty to query 440 * 441 * Returns the baud rate as an integer for this terminal. The 442 * termios lock must be held by the caller and the terminal bit 443 * flags may be updated. 444 * 445 * Locking: none 446 */ 447 static inline speed_t tty_get_baud_rate(struct tty_struct *tty) 448 { 449 return tty_termios_baud_rate(&tty->termios); 450 } 451 452 unsigned char tty_get_char_size(unsigned int cflag); 453 unsigned char tty_get_frame_size(unsigned int cflag); 454 455 void tty_termios_copy_hw(struct ktermios *new, const struct ktermios *old); 456 int tty_termios_hw_change(const struct ktermios *a, const struct ktermios *b); 457 int tty_set_termios(struct tty_struct *tty, struct ktermios *kt); 458 459 void tty_wakeup(struct tty_struct *tty); 460 461 int tty_mode_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg); 462 int tty_perform_flush(struct tty_struct *tty, unsigned long arg); 463 struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx); 464 void tty_release_struct(struct tty_struct *tty, int idx); 465 void tty_init_termios(struct tty_struct *tty); 466 void tty_save_termios(struct tty_struct *tty); 467 int tty_standard_install(struct tty_driver *driver, 468 struct tty_struct *tty); 469 470 extern struct mutex tty_mutex; 471 472 /* n_tty.c */ 473 void n_tty_inherit_ops(struct tty_ldisc_ops *ops); 474 #ifdef CONFIG_TTY 475 void __init n_tty_init(void); 476 #else 477 static inline void n_tty_init(void) { } 478 #endif 479 480 /* tty_audit.c */ 481 #ifdef CONFIG_AUDIT 482 void tty_audit_exit(void); 483 void tty_audit_fork(struct signal_struct *sig); 484 int tty_audit_push(void); 485 #else 486 static inline void tty_audit_exit(void) 487 { 488 } 489 static inline void tty_audit_fork(struct signal_struct *sig) 490 { 491 } 492 static inline int tty_audit_push(void) 493 { 494 return 0; 495 } 496 #endif 497 498 /* tty_ioctl.c */ 499 int n_tty_ioctl_helper(struct tty_struct *tty, unsigned int cmd, 500 unsigned long arg); 501 502 /* vt.c */ 503 504 int vt_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg); 505 506 long vt_compat_ioctl(struct tty_struct *tty, unsigned int cmd, 507 unsigned long arg); 508 509 /* tty_mutex.c */ 510 /* functions for preparation of BKL removal */ 511 void tty_lock(struct tty_struct *tty); 512 int tty_lock_interruptible(struct tty_struct *tty); 513 void tty_unlock(struct tty_struct *tty); 514 void tty_lock_slave(struct tty_struct *tty); 515 void tty_unlock_slave(struct tty_struct *tty); 516 void tty_set_lock_subclass(struct tty_struct *tty); 517 518 #endif 519