include/linux/tty.h

   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