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 */ 237 238 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 } 243 244 static inline bool tty_io_error(struct tty_struct *tty) 245 { 246 return test_bit(TTY_IO_ERROR, &tty->flags); 247 } 248 249 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 270 static inline void tty_kref_put(struct tty_struct *tty) 271 { } 272 static inline struct pid *tty_get_pgrp(struct tty_struct *tty) 273 { return NULL; } 274 static inline void tty_vhangup_self(void) 275 { } 276 static inline void disassociate_ctty(int priv) 277 { } 278 static inline dev_t tty_devnum(struct tty_struct *tty) 279 { return 0; } 280 static inline void proc_clear_tty(struct task_struct *p) 281 { } 282 static inline struct tty_struct *get_current_tty(void) 283 { return NULL; } 284 /* tty_io.c */ 285 static inline int __init tty_init(void) 286 { return 0; } 287 static inline const char *tty_name(const struct tty_struct *tty) 288 { return "(none)"; } 289 static inline struct tty_struct *tty_kopen_exclusive(dev_t device) 290 { return ERR_PTR(-ENODEV); } 291 static inline void tty_kclose(struct tty_struct *tty) 292 { } 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 */ 311 312 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 */ 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 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 398 static inline void tty_audit_exit(void) 399 { 400 } 401 static inline void tty_audit_fork(struct signal_struct *sig) 402 { 403 } 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