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 * @magic: magic value set early in @alloc_tty_struct to %TTY_MAGIC, for 126 * debugging purposes 127 * @kref: reference counting by tty_kref_get() and tty_kref_put(), reaching zero 128 * frees the structure 129 * @dev: class device or %NULL (e.g. ptys, serdev) 130 * @driver: &struct tty_driver operating this tty 131 * @ops: &struct tty_operations of @driver for this tty (open, close, etc.) 132 * @index: index of this tty (e.g. to construct @name like tty12) 133 * @ldisc_sem: protects line discipline changes (@ldisc) -- lock tty not pty 134 * @ldisc: the current line discipline for this tty (n_tty by default) 135 * @atomic_write_lock: protects against concurrent writers, i.e. locks 136 * @write_cnt, @write_buf and similar 137 * @legacy_mutex: leftover from history (BKL -> BTM -> @legacy_mutex), 138 * protecting several operations on this tty 139 * @throttle_mutex: protects against concurrent tty_throttle_safe() and 140 * tty_unthrottle_safe() (but not tty_unthrottle()) 141 * @termios_rwsem: protects @termios and @termios_locked 142 * @winsize_mutex: protects @winsize 143 * @termios: termios for the current tty, copied from/to @driver.termios 144 * @termios_locked: locked termios (by %TIOCGLCKTRMIOS and %TIOCSLCKTRMIOS 145 * ioctls) 146 * @name: name of the tty constructed by tty_line_name() (e.g. ttyS3) 147 * @flags: bitwise OR of %TTY_THROTTLED, %TTY_IO_ERROR, ... 148 * @count: count of open processes, reaching zero cancels all the work for 149 * this tty and drops a @kref too (but does not free this tty) 150 * @winsize: size of the terminal "window" (cf. @winsize_mutex) 151 * @flow: flow settings grouped together, see also @flow.unused 152 * @flow.lock: lock for @flow members 153 * @flow.stopped: tty stopped/started by stop_tty()/start_tty() 154 * @flow.tco_stopped: tty stopped/started by %TCOOFF/%TCOON ioctls (it has 155 * precedence over @flow.stopped) 156 * @flow.unused: alignment for Alpha, so that no members other than @flow.* are 157 * modified by the same 64b word store. The @flow's __aligned is 158 * there for the very same reason. 159 * @ctrl: control settings grouped together, see also @ctrl.unused 160 * @ctrl.lock: lock for @ctrl members 161 * @ctrl.pgrp: process group of this tty (setpgrp(2)) 162 * @ctrl.session: session of this tty (setsid(2)). Writes are protected by both 163 * @ctrl.lock and @legacy_mutex, readers must use at least one of 164 * them. 165 * @ctrl.pktstatus: packet mode status (bitwise OR of %TIOCPKT_ constants) 166 * @ctrl.packet: packet mode enabled 167 * @ctrl.unused: alignment for Alpha, see @flow.unused for explanation 168 * @hw_stopped: not controlled by the tty layer, under @driver's control for CTS 169 * handling 170 * @receive_room: bytes permitted to feed to @ldisc without any being lost 171 * @flow_change: controls behavior of throttling, see tty_throttle_safe() and 172 * tty_unthrottle_safe() 173 * @link: link to another pty (master -> slave and vice versa) 174 * @fasync: state for %O_ASYNC (for %SIGIO); managed by fasync_helper() 175 * @write_wait: concurrent writers are waiting in this queue until they are 176 * allowed to write 177 * @read_wait: readers wait for data in this queue 178 * @hangup_work: normally a work to perform a hangup (do_tty_hangup()); while 179 * freeing the tty, (re)used to release_one_tty() 180 * @disc_data: pointer to @ldisc's private data (e.g. to &struct n_tty_data) 181 * @driver_data: pointer to @driver's private data (e.g. &struct uart_state) 182 * @files_lock: protects @tty_files list 183 * @tty_files: list of (re)openers of this tty (i.e. linked &struct 184 * tty_file_private) 185 * @closing: when set during close, n_tty processes only START & STOP chars 186 * @write_buf: temporary buffer used during tty_write() to copy user data to 187 * @write_cnt: count of bytes written in tty_write() to @write_buf 188 * @SAK_work: if the tty has a pending do_SAK, it is queued here 189 * @port: persistent storage for this device (i.e. &struct tty_port) 190 * 191 * All of the state associated with a tty while the tty is open. Persistent 192 * storage for tty devices is referenced here as @port and is documented in 193 * &struct tty_port. 194 */ 195 struct tty_struct { 196 int magic; 197 struct kref kref; 198 struct device *dev; 199 struct tty_driver *driver; 200 const struct tty_operations *ops; 201 int index; 202 203 struct ld_semaphore ldisc_sem; 204 struct tty_ldisc *ldisc; 205 206 struct mutex atomic_write_lock; 207 struct mutex legacy_mutex; 208 struct mutex throttle_mutex; 209 struct rw_semaphore termios_rwsem; 210 struct mutex winsize_mutex; 211 struct ktermios termios, termios_locked; 212 char name[64]; 213 unsigned long flags; 214 int count; 215 struct winsize winsize; 216 217 struct { 218 spinlock_t lock; 219 bool stopped; 220 bool tco_stopped; 221 unsigned long unused[0]; 222 } __aligned(sizeof(unsigned long)) flow; 223 224 struct { 225 spinlock_t lock; 226 struct pid *pgrp; 227 struct pid *session; 228 unsigned char pktstatus; 229 bool packet; 230 unsigned long unused[0]; 231 } __aligned(sizeof(unsigned long)) ctrl; 232 233 int hw_stopped; 234 unsigned int receive_room; 235 int flow_change; 236 237 struct tty_struct *link; 238 struct fasync_struct *fasync; 239 wait_queue_head_t write_wait; 240 wait_queue_head_t read_wait; 241 struct work_struct hangup_work; 242 void *disc_data; 243 void *driver_data; 244 spinlock_t files_lock; 245 struct list_head tty_files; 246 247 #define N_TTY_BUF_SIZE 4096 248 249 int closing; 250 unsigned char *write_buf; 251 int write_cnt; 252 struct work_struct SAK_work; 253 struct tty_port *port; 254 } __randomize_layout; 255 256 /* Each of a tty's open files has private_data pointing to tty_file_private */ 257 struct tty_file_private { 258 struct tty_struct *tty; 259 struct file *file; 260 struct list_head list; 261 }; 262 263 /* tty magic number */ 264 #define TTY_MAGIC 0x5401 265 266 /* 267 * These bits are used in the flags field of the tty structure. 268 * 269 * So that interrupts won't be able to mess up the queues, 270 * copy_to_cooked must be atomic with respect to itself, as must 271 * tty->write. Thus, you must use the inline functions set_bit() and 272 * clear_bit() to make things atomic. 273 */ 274 #define TTY_THROTTLED 0 /* Call unthrottle() at threshold min */ 275 #define TTY_IO_ERROR 1 /* Cause an I/O error (may be no ldisc too) */ 276 #define TTY_OTHER_CLOSED 2 /* Other side (if any) has closed */ 277 #define TTY_EXCLUSIVE 3 /* Exclusive open mode */ 278 #define TTY_DO_WRITE_WAKEUP 5 /* Call write_wakeup after queuing new */ 279 #define TTY_LDISC_OPEN 11 /* Line discipline is open */ 280 #define TTY_PTY_LOCK 16 /* pty private */ 281 #define TTY_NO_WRITE_SPLIT 17 /* Preserve write boundaries to driver */ 282 #define TTY_HUPPED 18 /* Post driver->hangup() */ 283 #define TTY_HUPPING 19 /* Hangup in progress */ 284 #define TTY_LDISC_CHANGING 20 /* Change pending - non-block IO */ 285 #define TTY_LDISC_HALTED 22 /* Line discipline is halted */ 286 287 static inline bool tty_io_nonblock(struct tty_struct *tty, struct file *file) 288 { 289 return file->f_flags & O_NONBLOCK || 290 test_bit(TTY_LDISC_CHANGING, &tty->flags); 291 } 292 293 static inline bool tty_io_error(struct tty_struct *tty) 294 { 295 return test_bit(TTY_IO_ERROR, &tty->flags); 296 } 297 298 static inline bool tty_throttled(struct tty_struct *tty) 299 { 300 return test_bit(TTY_THROTTLED, &tty->flags); 301 } 302 303 #ifdef CONFIG_TTY 304 void tty_kref_put(struct tty_struct *tty); 305 struct pid *tty_get_pgrp(struct tty_struct *tty); 306 void tty_vhangup_self(void); 307 void disassociate_ctty(int priv); 308 dev_t tty_devnum(struct tty_struct *tty); 309 void proc_clear_tty(struct task_struct *p); 310 struct tty_struct *get_current_tty(void); 311 /* tty_io.c */ 312 int __init tty_init(void); 313 const char *tty_name(const struct tty_struct *tty); 314 struct tty_struct *tty_kopen_exclusive(dev_t device); 315 struct tty_struct *tty_kopen_shared(dev_t device); 316 void tty_kclose(struct tty_struct *tty); 317 int tty_dev_name_to_number(const char *name, dev_t *number); 318 #else 319 static inline void tty_kref_put(struct tty_struct *tty) 320 { } 321 static inline struct pid *tty_get_pgrp(struct tty_struct *tty) 322 { return NULL; } 323 static inline void tty_vhangup_self(void) 324 { } 325 static inline void disassociate_ctty(int priv) 326 { } 327 static inline dev_t tty_devnum(struct tty_struct *tty) 328 { return 0; } 329 static inline void proc_clear_tty(struct task_struct *p) 330 { } 331 static inline struct tty_struct *get_current_tty(void) 332 { return NULL; } 333 /* tty_io.c */ 334 static inline int __init tty_init(void) 335 { return 0; } 336 static inline const char *tty_name(const struct tty_struct *tty) 337 { return "(none)"; } 338 static inline struct tty_struct *tty_kopen_exclusive(dev_t device) 339 { return ERR_PTR(-ENODEV); } 340 static inline void tty_kclose(struct tty_struct *tty) 341 { } 342 static inline int tty_dev_name_to_number(const char *name, dev_t *number) 343 { return -ENOTSUPP; } 344 #endif 345 346 extern struct ktermios tty_std_termios; 347 348 int vcs_init(void); 349 350 extern struct class *tty_class; 351 352 /** 353 * tty_kref_get - get a tty reference 354 * @tty: tty device 355 * 356 * Return a new reference to a tty object. The caller must hold 357 * sufficient locks/counts to ensure that their existing reference cannot 358 * go away 359 */ 360 361 static inline struct tty_struct *tty_kref_get(struct tty_struct *tty) 362 { 363 if (tty) 364 kref_get(&tty->kref); 365 return tty; 366 } 367 368 const char *tty_driver_name(const struct tty_struct *tty); 369 void tty_wait_until_sent(struct tty_struct *tty, long timeout); 370 void stop_tty(struct tty_struct *tty); 371 void start_tty(struct tty_struct *tty); 372 void tty_write_message(struct tty_struct *tty, char *msg); 373 int tty_send_xchar(struct tty_struct *tty, char ch); 374 int tty_put_char(struct tty_struct *tty, unsigned char c); 375 unsigned int tty_chars_in_buffer(struct tty_struct *tty); 376 unsigned int tty_write_room(struct tty_struct *tty); 377 void tty_driver_flush_buffer(struct tty_struct *tty); 378 void tty_unthrottle(struct tty_struct *tty); 379 int tty_throttle_safe(struct tty_struct *tty); 380 int tty_unthrottle_safe(struct tty_struct *tty); 381 int tty_do_resize(struct tty_struct *tty, struct winsize *ws); 382 int tty_get_icount(struct tty_struct *tty, 383 struct serial_icounter_struct *icount); 384 int is_current_pgrp_orphaned(void); 385 void tty_hangup(struct tty_struct *tty); 386 void tty_vhangup(struct tty_struct *tty); 387 int tty_hung_up_p(struct file *filp); 388 void do_SAK(struct tty_struct *tty); 389 void __do_SAK(struct tty_struct *tty); 390 void no_tty(void); 391 speed_t tty_termios_baud_rate(struct ktermios *termios); 392 void tty_termios_encode_baud_rate(struct ktermios *termios, speed_t ibaud, 393 speed_t obaud); 394 void tty_encode_baud_rate(struct tty_struct *tty, speed_t ibaud, 395 speed_t obaud); 396 397 /** 398 * tty_get_baud_rate - get tty bit rates 399 * @tty: tty to query 400 * 401 * Returns the baud rate as an integer for this terminal. The 402 * termios lock must be held by the caller and the terminal bit 403 * flags may be updated. 404 * 405 * Locking: none 406 */ 407 static inline speed_t tty_get_baud_rate(struct tty_struct *tty) 408 { 409 return tty_termios_baud_rate(&tty->termios); 410 } 411 412 unsigned char tty_get_char_size(unsigned int cflag); 413 unsigned char tty_get_frame_size(unsigned int cflag); 414 415 void tty_termios_copy_hw(struct ktermios *new, struct ktermios *old); 416 int tty_termios_hw_change(const struct ktermios *a, const struct ktermios *b); 417 int tty_set_termios(struct tty_struct *tty, struct ktermios *kt); 418 419 void tty_wakeup(struct tty_struct *tty); 420 421 int tty_mode_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg); 422 int tty_perform_flush(struct tty_struct *tty, unsigned long arg); 423 struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx); 424 void tty_release_struct(struct tty_struct *tty, int idx); 425 void tty_init_termios(struct tty_struct *tty); 426 void tty_save_termios(struct tty_struct *tty); 427 int tty_standard_install(struct tty_driver *driver, 428 struct tty_struct *tty); 429 430 extern struct mutex tty_mutex; 431 432 /* n_tty.c */ 433 void n_tty_inherit_ops(struct tty_ldisc_ops *ops); 434 #ifdef CONFIG_TTY 435 void __init n_tty_init(void); 436 #else 437 static inline void n_tty_init(void) { } 438 #endif 439 440 /* tty_audit.c */ 441 #ifdef CONFIG_AUDIT 442 void tty_audit_exit(void); 443 void tty_audit_fork(struct signal_struct *sig); 444 int tty_audit_push(void); 445 #else 446 static inline void tty_audit_exit(void) 447 { 448 } 449 static inline void tty_audit_fork(struct signal_struct *sig) 450 { 451 } 452 static inline int tty_audit_push(void) 453 { 454 return 0; 455 } 456 #endif 457 458 /* tty_ioctl.c */ 459 int n_tty_ioctl_helper(struct tty_struct *tty, unsigned int cmd, 460 unsigned long arg); 461 462 /* vt.c */ 463 464 int vt_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg); 465 466 long vt_compat_ioctl(struct tty_struct *tty, unsigned int cmd, 467 unsigned long arg); 468 469 /* tty_mutex.c */ 470 /* functions for preparation of BKL removal */ 471 void tty_lock(struct tty_struct *tty); 472 int tty_lock_interruptible(struct tty_struct *tty); 473 void tty_unlock(struct tty_struct *tty); 474 void tty_lock_slave(struct tty_struct *tty); 475 void tty_unlock_slave(struct tty_struct *tty); 476 void tty_set_lock_subclass(struct tty_struct *tty); 477 478 #endif 479