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_driver.h>
  10 #include <linux/tty_ldisc.h>
  11 #include <linux/mutex.h>
  12 #include <linux/tty_flags.h>
  13 #include <linux/seq_file.h>
  14 #include <uapi/linux/tty.h>
  15 #include <linux/rwsem.h>
  16 #include <linux/llist.h>
  17
  18
  19 /*
  20  * Lock subclasses for tty locks
  21  *
  22  * TTY_LOCK_NORMAL is for normal ttys and master ptys.
  23  * TTY_LOCK_SLAVE is for slave ptys only.
  24  *
  25  * Lock subclasses are necessary for handling nested locking with pty pairs.
  26  * tty locks which use nested locking:
  27  *
  28  * legacy_mutex - Nested tty locks are necessary for releasing pty pairs.
  29  *                The stable lock order is master pty first, then slave pty.
  30  * termios_rwsem - The stable lock order is tty_buffer lock->termios_rwsem.
  31  *                 Subclassing this lock enables the slave pty to hold its
  32  *                 termios_rwsem when claiming the master tty_buffer lock.
  33  * tty_buffer lock - slave ptys can claim nested buffer lock when handling
  34  *                   signal chars. The stable lock order is slave pty, then
  35  *                   master.
  36  */
  37
  38 enum {
  39         TTY_LOCK_NORMAL = 0,
  40         TTY_LOCK_SLAVE,
  41 };
  42
  43 /*
  44  * (Note: the *_driver.minor_start values 1, 64, 128, 192 are
  45  * hardcoded at present.)
  46  */
  47 #define NR_UNIX98_PTY_DEFAULT   4096      /* Default maximum for Unix98 ptys */
  48 #define NR_UNIX98_PTY_RESERVE   1024      /* Default reserve for main devpts */
  49 #define NR_UNIX98_PTY_MAX       (1 << MINORBITS) /* Absolute limit */
  50
  51 /*
  52  * This character is the same as _POSIX_VDISABLE: it cannot be used as
  53  * a c_cc[] character, but indicates that a particular special character
  54  * isn't in use (eg VINTR has no character etc)
  55  */
  56 #define __DISABLED_CHAR '\0'
  57
  58 struct tty_buffer {
  59         union {
  60                 struct tty_buffer *next;
  61                 struct llist_node free;
  62         };
  63         int used;
  64         int size;
  65         int commit;
  66         int read;
  67         int flags;
  68         /* Data points here */
  69         unsigned long data[0];
  70 };
  71
  72 /* Values for .flags field of tty_buffer */
  73 #define TTYB_NORMAL     1       /* buffer has no flags buffer */
  74
  75 static inline unsigned char *char_buf_ptr(struct tty_buffer *b, int ofs)
  76 {
  77         return ((unsigned char *)b->data) + ofs;
  78 }
  79
  80 static inline char *flag_buf_ptr(struct tty_buffer *b, int ofs)
  81 {
  82         return (char *)char_buf_ptr(b, ofs) + b->size;
  83 }
  84
  85 struct tty_bufhead {
  86         struct tty_buffer *head;        /* Queue head */
  87         struct work_struct work;
  88         struct mutex       lock;
  89         atomic_t           priority;
  90         struct tty_buffer sentinel;
  91         struct llist_head free;         /* Free queue head */
  92         atomic_t           mem_used;    /* In-use buffers excluding free list */
  93         int                mem_limit;
  94         struct tty_buffer *tail;        /* Active buffer */
  95 };
  96 /*
  97  * When a break, frame error, or parity error happens, these codes are
  98  * stuffed into the flags buffer.
  99  */
 100 #define TTY_NORMAL      0
 101 #define TTY_BREAK       1
 102 #define TTY_FRAME       2
 103 #define TTY_PARITY      3
 104 #define TTY_OVERRUN     4
 105
 106 #define INTR_CHAR(tty) ((tty)->termios.c_cc[VINTR])
 107 #define QUIT_CHAR(tty) ((tty)->termios.c_cc[VQUIT])
 108 #define ERASE_CHAR(tty) ((tty)->termios.c_cc[VERASE])
 109 #define KILL_CHAR(tty) ((tty)->termios.c_cc[VKILL])
 110 #define EOF_CHAR(tty) ((tty)->termios.c_cc[VEOF])
 111 #define TIME_CHAR(tty) ((tty)->termios.c_cc[VTIME])
 112 #define MIN_CHAR(tty) ((tty)->termios.c_cc[VMIN])
 113 #define SWTC_CHAR(tty) ((tty)->termios.c_cc[VSWTC])
 114 #define START_CHAR(tty) ((tty)->termios.c_cc[VSTART])
 115 #define STOP_CHAR(tty) ((tty)->termios.c_cc[VSTOP])
 116 #define SUSP_CHAR(tty) ((tty)->termios.c_cc[VSUSP])
 117 #define EOL_CHAR(tty) ((tty)->termios.c_cc[VEOL])
 118 #define REPRINT_CHAR(tty) ((tty)->termios.c_cc[VREPRINT])
 119 #define DISCARD_CHAR(tty) ((tty)->termios.c_cc[VDISCARD])
 120 #define WERASE_CHAR(tty) ((tty)->termios.c_cc[VWERASE])
 121 #define LNEXT_CHAR(tty) ((tty)->termios.c_cc[VLNEXT])
 122 #define EOL2_CHAR(tty) ((tty)->termios.c_cc[VEOL2])
 123
 124 #define _I_FLAG(tty, f) ((tty)->termios.c_iflag & (f))
 125 #define _O_FLAG(tty, f) ((tty)->termios.c_oflag & (f))
 126 #define _C_FLAG(tty, f) ((tty)->termios.c_cflag & (f))
 127 #define _L_FLAG(tty, f) ((tty)->termios.c_lflag & (f))
 128
 129 #define I_IGNBRK(tty)   _I_FLAG((tty), IGNBRK)
 130 #define I_BRKINT(tty)   _I_FLAG((tty), BRKINT)
 131 #define I_IGNPAR(tty)   _I_FLAG((tty), IGNPAR)
 132 #define I_PARMRK(tty)   _I_FLAG((tty), PARMRK)
 133 #define I_INPCK(tty)    _I_FLAG((tty), INPCK)
 134 #define I_ISTRIP(tty)   _I_FLAG((tty), ISTRIP)
 135 #define I_INLCR(tty)    _I_FLAG((tty), INLCR)
 136 #define I_IGNCR(tty)    _I_FLAG((tty), IGNCR)
 137 #define I_ICRNL(tty)    _I_FLAG((tty), ICRNL)
 138 #define I_IUCLC(tty)    _I_FLAG((tty), IUCLC)
 139 #define I_IXON(tty)     _I_FLAG((tty), IXON)
 140 #define I_IXANY(tty)    _I_FLAG((tty), IXANY)
 141 #define I_IXOFF(tty)    _I_FLAG((tty), IXOFF)
 142 #define I_IMAXBEL(tty)  _I_FLAG((tty), IMAXBEL)
 143 #define I_IUTF8(tty)    _I_FLAG((tty), IUTF8)
 144
 145 #define O_OPOST(tty)    _O_FLAG((tty), OPOST)
 146 #define O_OLCUC(tty)    _O_FLAG((tty), OLCUC)
 147 #define O_ONLCR(tty)    _O_FLAG((tty), ONLCR)
 148 #define O_OCRNL(tty)    _O_FLAG((tty), OCRNL)
 149 #define O_ONOCR(tty)    _O_FLAG((tty), ONOCR)
 150 #define O_ONLRET(tty)   _O_FLAG((tty), ONLRET)
 151 #define O_OFILL(tty)    _O_FLAG((tty), OFILL)
 152 #define O_OFDEL(tty)    _O_FLAG((tty), OFDEL)
 153 #define O_NLDLY(tty)    _O_FLAG((tty), NLDLY)
 154 #define O_CRDLY(tty)    _O_FLAG((tty), CRDLY)
 155 #define O_TABDLY(tty)   _O_FLAG((tty), TABDLY)
 156 #define O_BSDLY(tty)    _O_FLAG((tty), BSDLY)
 157 #define O_VTDLY(tty)    _O_FLAG((tty), VTDLY)
 158 #define O_FFDLY(tty)    _O_FLAG((tty), FFDLY)
 159
 160 #define C_BAUD(tty)     _C_FLAG((tty), CBAUD)
 161 #define C_CSIZE(tty)    _C_FLAG((tty), CSIZE)
 162 #define C_CSTOPB(tty)   _C_FLAG((tty), CSTOPB)
 163 #define C_CREAD(tty)    _C_FLAG((tty), CREAD)
 164 #define C_PARENB(tty)   _C_FLAG((tty), PARENB)
 165 #define C_PARODD(tty)   _C_FLAG((tty), PARODD)
 166 #define C_HUPCL(tty)    _C_FLAG((tty), HUPCL)
 167 #define C_CLOCAL(tty)   _C_FLAG((tty), CLOCAL)
 168 #define C_CIBAUD(tty)   _C_FLAG((tty), CIBAUD)
 169 #define C_CRTSCTS(tty)  _C_FLAG((tty), CRTSCTS)
 170 #define C_CMSPAR(tty)   _C_FLAG((tty), CMSPAR)
 171
 172 #define L_ISIG(tty)     _L_FLAG((tty), ISIG)
 173 #define L_ICANON(tty)   _L_FLAG((tty), ICANON)
 174 #define L_XCASE(tty)    _L_FLAG((tty), XCASE)
 175 #define L_ECHO(tty)     _L_FLAG((tty), ECHO)
 176 #define L_ECHOE(tty)    _L_FLAG((tty), ECHOE)
 177 #define L_ECHOK(tty)    _L_FLAG((tty), ECHOK)
 178 #define L_ECHONL(tty)   _L_FLAG((tty), ECHONL)
 179 #define L_NOFLSH(tty)   _L_FLAG((tty), NOFLSH)
 180 #define L_TOSTOP(tty)   _L_FLAG((tty), TOSTOP)
 181 #define L_ECHOCTL(tty)  _L_FLAG((tty), ECHOCTL)
 182 #define L_ECHOPRT(tty)  _L_FLAG((tty), ECHOPRT)
 183 #define L_ECHOKE(tty)   _L_FLAG((tty), ECHOKE)
 184 #define L_FLUSHO(tty)   _L_FLAG((tty), FLUSHO)
 185 #define L_PENDIN(tty)   _L_FLAG((tty), PENDIN)
 186 #define L_IEXTEN(tty)   _L_FLAG((tty), IEXTEN)
 187 #define L_EXTPROC(tty)  _L_FLAG((tty), EXTPROC)
 188
 189 struct device;
 190 struct signal_struct;
 191
 192 /*
 193  * Port level information. Each device keeps its own port level information
 194  * so provide a common structure for those ports wanting to use common support
 195  * routines.
 196  *
 197  * The tty port has a different lifetime to the tty so must be kept apart.
 198  * In addition be careful as tty -> port mappings are valid for the life
 199  * of the tty object but in many cases port -> tty mappings are valid only
 200  * until a hangup so don't use the wrong path.
 201  */
 202
 203 struct tty_port;
 204
 205 struct tty_port_operations {
 206         /* Return 1 if the carrier is raised */
 207         int (*carrier_raised)(struct tty_port *port);
 208         /* Control the DTR line */
 209         void (*dtr_rts)(struct tty_port *port, int raise);
 210         /* Called when the last close completes or a hangup finishes
 211            IFF the port was initialized. Do not use to free resources. Called
 212            under the port mutex to serialize against activate/shutdowns */
 213         void (*shutdown)(struct tty_port *port);
 214         /* Called under the port mutex from tty_port_open, serialized using
 215            the port mutex */
 216         /* FIXME: long term getting the tty argument *out* of this would be
 217            good for consoles */
 218         int (*activate)(struct tty_port *port, struct tty_struct *tty);
 219         /* Called on the final put of a port */
 220         void (*destruct)(struct tty_port *port);
 221 };
 222
 223 struct tty_port_client_operations {
 224         int (*receive_buf)(struct tty_port *port, const unsigned char *, const unsigned char *, size_t);
 225         void (*write_wakeup)(struct tty_port *port);
 226 };
 227
 228 extern const struct tty_port_client_operations tty_port_default_client_ops;
 229
 230 struct tty_port {
 231         struct tty_bufhead      buf;            /* Locked internally */
 232         struct tty_struct       *tty;           /* Back pointer */
 233         struct tty_struct       *itty;          /* internal back ptr */
 234         const struct tty_port_operations *ops;  /* Port operations */
 235         const struct tty_port_client_operations *client_ops; /* Port client operations */
 236         spinlock_t              lock;           /* Lock protecting tty field */
 237         int                     blocked_open;   /* Waiting to open */
 238         int                     count;          /* Usage count */
 239         wait_queue_head_t       open_wait;      /* Open waiters */
 240         wait_queue_head_t       delta_msr_wait; /* Modem status change */
 241         unsigned long           flags;          /* User TTY flags ASYNC_ */
 242         unsigned long           iflags;         /* Internal flags TTY_PORT_ */
 243         unsigned char           console:1,      /* port is a console */
 244                                 low_latency:1;  /* optional: tune for latency */
 245         struct mutex            mutex;          /* Locking */
 246         struct mutex            buf_mutex;      /* Buffer alloc lock */
 247         unsigned char           *xmit_buf;      /* Optional buffer */
 248         unsigned int            close_delay;    /* Close port delay */
 249         unsigned int            closing_wait;   /* Delay for output */
 250         int                     drain_delay;    /* Set to zero if no pure time
 251                                                    based drain is needed else
 252                                                    set to size of fifo */
 253         struct kref             kref;           /* Ref counter */
 254         void                    *client_data;
 255 };
 256
 257 /* tty_port::iflags bits -- use atomic bit ops */
 258 #define TTY_PORT_INITIALIZED    0       /* device is initialized */
 259 #define TTY_PORT_SUSPENDED      1       /* device is suspended */
 260 #define TTY_PORT_ACTIVE         2       /* device is open */
 261
 262 /*
 263  * uart drivers: use the uart_port::status field and the UPSTAT_* defines
 264  * for s/w-based flow control steering and carrier detection status
 265  */
 266 #define TTY_PORT_CTS_FLOW       3       /* h/w flow control enabled */
 267 #define TTY_PORT_CHECK_CD       4       /* carrier detect enabled */
 268 #define TTY_PORT_KOPENED        5       /* device exclusively opened by
 269                                            kernel */
 270
 271 /*
 272  * Where all of the state associated with a tty is kept while the tty
 273  * is open.  Since the termios state should be kept even if the tty
 274  * has been closed --- for things like the baud rate, etc --- it is
 275  * not stored here, but rather a pointer to the real state is stored
 276  * here.  Possible the winsize structure should have the same
 277  * treatment, but (1) the default 80x24 is usually right and (2) it's
 278  * most often used by a windowing system, which will set the correct
 279  * size each time the window is created or resized anyway.
 280  *                                              - TYT, 9/14/92
 281  */
 282
 283 struct tty_operations;
 284
 285 struct tty_struct {
 286         int     magic;
 287         struct kref kref;
 288         struct device *dev;
 289         struct tty_driver *driver;
 290         const struct tty_operations *ops;
 291         int index;
 292
 293         /* Protects ldisc changes: Lock tty not pty */
 294         struct ld_semaphore ldisc_sem;
 295         struct tty_ldisc *ldisc;
 296
 297         struct mutex atomic_write_lock;
 298         struct mutex legacy_mutex;
 299         struct mutex throttle_mutex;
 300         struct rw_semaphore termios_rwsem;
 301         struct mutex winsize_mutex;
 302         spinlock_t ctrl_lock;
 303         spinlock_t flow_lock;
 304         /* Termios values are protected by the termios rwsem */
 305         struct ktermios termios, termios_locked;
 306         struct termiox *termiox;        /* May be NULL for unsupported */
 307         char name[64];
 308         struct pid *pgrp;               /* Protected by ctrl lock */
 309         struct pid *session;
 310         unsigned long flags;
 311         int count;
 312         struct winsize winsize;         /* winsize_mutex */
 313         unsigned long stopped:1,        /* flow_lock */
 314                       flow_stopped:1,
 315                       unused:BITS_PER_LONG - 2;
 316         int hw_stopped;
 317         unsigned long ctrl_status:8,    /* ctrl_lock */
 318                       packet:1,
 319                       unused_ctrl:BITS_PER_LONG - 9;
 320         unsigned int receive_room;      /* Bytes free for queue */
 321         int flow_change;
 322
 323         struct tty_struct *link;
 324         struct fasync_struct *fasync;
 325         wait_queue_head_t write_wait;
 326         wait_queue_head_t read_wait;
 327         struct work_struct hangup_work;
 328         void *disc_data;
 329         void *driver_data;
 330         spinlock_t files_lock;          /* protects tty_files list */
 331         struct list_head tty_files;
 332
 333 #define N_TTY_BUF_SIZE 4096
 334
 335         int closing;
 336         unsigned char *write_buf;
 337         int write_cnt;
 338         /* If the tty has a pending do_SAK, queue it here - akpm */
 339         struct work_struct SAK_work;
 340         struct tty_port *port;
 341 } __randomize_layout;
 342
 343 /* Each of a tty's open files has private_data pointing to tty_file_private */
 344 struct tty_file_private {
 345         struct tty_struct *tty;
 346         struct file *file;
 347         struct list_head list;
 348 };
 349
 350 /* tty magic number */
 351 #define TTY_MAGIC               0x5401
 352
 353 /*
 354  * These bits are used in the flags field of the tty structure.
 355  *
 356  * So that interrupts won't be able to mess up the queues,
 357  * copy_to_cooked must be atomic with respect to itself, as must
 358  * tty->write.  Thus, you must use the inline functions set_bit() and
 359  * clear_bit() to make things atomic.
 360  */
 361 #define TTY_THROTTLED           0       /* Call unthrottle() at threshold min */
 362 #define TTY_IO_ERROR            1       /* Cause an I/O error (may be no ldisc too) */
 363 #define TTY_OTHER_CLOSED        2       /* Other side (if any) has closed */
 364 #define TTY_EXCLUSIVE           3       /* Exclusive open mode */
 365 #define TTY_DO_WRITE_WAKEUP     5       /* Call write_wakeup after queuing new */
 366 #define TTY_LDISC_OPEN          11      /* Line discipline is open */
 367 #define TTY_PTY_LOCK            16      /* pty private */
 368 #define TTY_NO_WRITE_SPLIT      17      /* Preserve write boundaries to driver */
 369 #define TTY_HUPPED              18      /* Post driver->hangup() */
 370 #define TTY_HUPPING             19      /* Hangup in progress */
 371 #define TTY_LDISC_CHANGING      20      /* Change pending - non-block IO */
 372 #define TTY_LDISC_HALTED        22      /* Line discipline is halted */
 373
 374 /* Values for tty->flow_change */
 375 #define TTY_THROTTLE_SAFE 1
 376 #define TTY_UNTHROTTLE_SAFE 2
 377
 378 static inline void __tty_set_flow_change(struct tty_struct *tty, int val)
 379 {
 380         tty->flow_change = val;
 381 }
 382
 383 static inline void tty_set_flow_change(struct tty_struct *tty, int val)
 384 {
 385         tty->flow_change = val;
 386         smp_mb();
 387 }
 388
 389 static inline bool tty_io_nonblock(struct tty_struct *tty, struct file *file)
 390 {
 391         return file->f_flags & O_NONBLOCK ||
 392                 test_bit(TTY_LDISC_CHANGING, &tty->flags);
 393 }
 394
 395 static inline bool tty_io_error(struct tty_struct *tty)
 396 {
 397         return test_bit(TTY_IO_ERROR, &tty->flags);
 398 }
 399
 400 static inline bool tty_throttled(struct tty_struct *tty)
 401 {
 402         return test_bit(TTY_THROTTLED, &tty->flags);
 403 }
 404
 405 #ifdef CONFIG_TTY
 406 extern void tty_kref_put(struct tty_struct *tty);
 407 extern struct pid *tty_get_pgrp(struct tty_struct *tty);
 408 extern void tty_vhangup_self(void);
 409 extern void disassociate_ctty(int priv);
 410 extern dev_t tty_devnum(struct tty_struct *tty);
 411 extern void proc_clear_tty(struct task_struct *p);
 412 extern struct tty_struct *get_current_tty(void);
 413 /* tty_io.c */
 414 extern int __init tty_init(void);
 415 extern const char *tty_name(const struct tty_struct *tty);
 416 extern struct tty_struct *tty_kopen(dev_t device);
 417 extern void tty_kclose(struct tty_struct *tty);
 418 extern int tty_dev_name_to_number(const char *name, dev_t *number);
 419 extern int tty_ldisc_lock(struct tty_struct *tty, unsigned long timeout);
 420 extern void tty_ldisc_unlock(struct tty_struct *tty);
 421 #else
 422 static inline void tty_kref_put(struct tty_struct *tty)
 423 { }
 424 static inline struct pid *tty_get_pgrp(struct tty_struct *tty)
 425 { return NULL; }
 426 static inline void tty_vhangup_self(void)
 427 { }
 428 static inline void disassociate_ctty(int priv)
 429 { }
 430 static inline dev_t tty_devnum(struct tty_struct *tty)
 431 { return 0; }
 432 static inline void proc_clear_tty(struct task_struct *p)
 433 { }
 434 static inline struct tty_struct *get_current_tty(void)
 435 { return NULL; }
 436 /* tty_io.c */
 437 static inline int __init tty_init(void)
 438 { return 0; }
 439 static inline const char *tty_name(const struct tty_struct *tty)
 440 { return "(none)"; }
 441 static inline struct tty_struct *tty_kopen(dev_t device)
 442 { return ERR_PTR(-ENODEV); }
 443 static inline void tty_kclose(struct tty_struct *tty)
 444 { }
 445 static inline int tty_dev_name_to_number(const char *name, dev_t *number)
 446 { return -ENOTSUPP; }
 447 #endif
 448
 449 extern struct ktermios tty_std_termios;
 450
 451 extern int vcs_init(void);
 452
 453 extern struct class *tty_class;
 454
 455 /**
 456  *      tty_kref_get            -       get a tty reference
 457  *      @tty: tty device
 458  *
 459  *      Return a new reference to a tty object. The caller must hold
 460  *      sufficient locks/counts to ensure that their existing reference cannot
 461  *      go away
 462  */
 463
 464 static inline struct tty_struct *tty_kref_get(struct tty_struct *tty)
 465 {
 466         if (tty)
 467                 kref_get(&tty->kref);
 468         return tty;
 469 }
 470
 471 extern const char *tty_driver_name(const struct tty_struct *tty);
 472 extern void tty_wait_until_sent(struct tty_struct *tty, long timeout);
 473 extern int __tty_check_change(struct tty_struct *tty, int sig);
 474 extern int tty_check_change(struct tty_struct *tty);
 475 extern void __stop_tty(struct tty_struct *tty);
 476 extern void stop_tty(struct tty_struct *tty);
 477 extern void __start_tty(struct tty_struct *tty);
 478 extern void start_tty(struct tty_struct *tty);
 479 extern int tty_register_driver(struct tty_driver *driver);
 480 extern int tty_unregister_driver(struct tty_driver *driver);
 481 extern struct device *tty_register_device(struct tty_driver *driver,
 482                                           unsigned index, struct device *dev);
 483 extern struct device *tty_register_device_attr(struct tty_driver *driver,
 484                                 unsigned index, struct device *device,
 485                                 void *drvdata,
 486                                 const struct attribute_group **attr_grp);
 487 extern void tty_unregister_device(struct tty_driver *driver, unsigned index);
 488 extern void tty_write_message(struct tty_struct *tty, char *msg);
 489 extern int tty_send_xchar(struct tty_struct *tty, char ch);
 490 extern int tty_put_char(struct tty_struct *tty, unsigned char c);
 491 extern int tty_chars_in_buffer(struct tty_struct *tty);
 492 extern int tty_write_room(struct tty_struct *tty);
 493 extern void tty_driver_flush_buffer(struct tty_struct *tty);
 494 extern void tty_throttle(struct tty_struct *tty);
 495 extern void tty_unthrottle(struct tty_struct *tty);
 496 extern int tty_throttle_safe(struct tty_struct *tty);
 497 extern int tty_unthrottle_safe(struct tty_struct *tty);
 498 extern int tty_do_resize(struct tty_struct *tty, struct winsize *ws);
 499 extern int is_current_pgrp_orphaned(void);
 500 extern void tty_hangup(struct tty_struct *tty);
 501 extern void tty_vhangup(struct tty_struct *tty);
 502 extern void tty_vhangup_session(struct tty_struct *tty);
 503 extern int tty_hung_up_p(struct file *filp);
 504 extern void do_SAK(struct tty_struct *tty);
 505 extern void __do_SAK(struct tty_struct *tty);
 506 extern void tty_open_proc_set_tty(struct file *filp, struct tty_struct *tty);
 507 extern int tty_signal_session_leader(struct tty_struct *tty, int exit_session);
 508 extern void session_clear_tty(struct pid *session);
 509 extern void no_tty(void);
 510 extern void tty_buffer_free_all(struct tty_port *port);
 511 extern void tty_buffer_flush(struct tty_struct *tty, struct tty_ldisc *ld);
 512 extern void tty_buffer_init(struct tty_port *port);
 513 extern void tty_buffer_set_lock_subclass(struct tty_port *port);
 514 extern bool tty_buffer_restart_work(struct tty_port *port);
 515 extern bool tty_buffer_cancel_work(struct tty_port *port);
 516 extern void tty_buffer_flush_work(struct tty_port *port);
 517 extern speed_t tty_termios_baud_rate(struct ktermios *termios);
 518 extern speed_t tty_termios_input_baud_rate(struct ktermios *termios);
 519 extern void tty_termios_encode_baud_rate(struct ktermios *termios,
 520                                                 speed_t ibaud, speed_t obaud);
 521 extern void tty_encode_baud_rate(struct tty_struct *tty,
 522                                                 speed_t ibaud, speed_t obaud);
 523
 524 /**
 525  *      tty_get_baud_rate       -       get tty bit rates
 526  *      @tty: tty to query
 527  *
 528  *      Returns the baud rate as an integer for this terminal. The
 529  *      termios lock must be held by the caller and the terminal bit
 530  *      flags may be updated.
 531  *
 532  *      Locking: none
 533  */
 534 static inline speed_t tty_get_baud_rate(struct tty_struct *tty)
 535 {
 536         return tty_termios_baud_rate(&tty->termios);
 537 }
 538
 539 extern void tty_termios_copy_hw(struct ktermios *new, struct ktermios *old);
 540 extern int tty_termios_hw_change(const struct ktermios *a, const struct ktermios *b);
 541 extern int tty_set_termios(struct tty_struct *tty, struct ktermios *kt);
 542
 543 extern struct tty_ldisc *tty_ldisc_ref(struct tty_struct *);
 544 extern void tty_ldisc_deref(struct tty_ldisc *);
 545 extern struct tty_ldisc *tty_ldisc_ref_wait(struct tty_struct *);
 546 extern void tty_ldisc_hangup(struct tty_struct *tty, bool reset);
 547 extern int tty_ldisc_reinit(struct tty_struct *tty, int disc);
 548 extern const struct seq_operations tty_ldiscs_seq_ops;
 549
 550 extern void tty_wakeup(struct tty_struct *tty);
 551 extern void tty_ldisc_flush(struct tty_struct *tty);
 552
 553 extern long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
 554 extern int tty_mode_ioctl(struct tty_struct *tty, struct file *file,
 555                         unsigned int cmd, unsigned long arg);
 556 extern long tty_jobctrl_ioctl(struct tty_struct *tty, struct tty_struct *real_tty,
 557                               struct file *file, unsigned int cmd, unsigned long arg);
 558 extern int tty_perform_flush(struct tty_struct *tty, unsigned long arg);
 559 extern void tty_default_fops(struct file_operations *fops);
 560 extern struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx);
 561 extern int tty_alloc_file(struct file *file);
 562 extern void tty_add_file(struct tty_struct *tty, struct file *file);
 563 extern void tty_free_file(struct file *file);
 564 extern struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx);
 565 extern void tty_release_struct(struct tty_struct *tty, int idx);
 566 extern int tty_release(struct inode *inode, struct file *filp);
 567 extern void tty_init_termios(struct tty_struct *tty);
 568 extern void tty_save_termios(struct tty_struct *tty);
 569 extern int tty_standard_install(struct tty_driver *driver,
 570                 struct tty_struct *tty);
 571
 572 extern struct mutex tty_mutex;
 573
 574 #define tty_is_writelocked(tty)  (mutex_is_locked(&tty->atomic_write_lock))
 575
 576 extern void tty_port_init(struct tty_port *port);
 577 extern void tty_port_link_device(struct tty_port *port,
 578                 struct tty_driver *driver, unsigned index);
 579 extern struct device *tty_port_register_device(struct tty_port *port,
 580                 struct tty_driver *driver, unsigned index,
 581                 struct device *device);
 582 extern struct device *tty_port_register_device_attr(struct tty_port *port,
 583                 struct tty_driver *driver, unsigned index,
 584                 struct device *device, void *drvdata,
 585                 const struct attribute_group **attr_grp);
 586 extern struct device *tty_port_register_device_serdev(struct tty_port *port,
 587                 struct tty_driver *driver, unsigned index,
 588                 struct device *device);
 589 extern struct device *tty_port_register_device_attr_serdev(struct tty_port *port,
 590                 struct tty_driver *driver, unsigned index,
 591                 struct device *device, void *drvdata,
 592                 const struct attribute_group **attr_grp);
 593 extern void tty_port_unregister_device(struct tty_port *port,
 594                 struct tty_driver *driver, unsigned index);
 595 extern int tty_port_alloc_xmit_buf(struct tty_port *port);
 596 extern void tty_port_free_xmit_buf(struct tty_port *port);
 597 extern void tty_port_destroy(struct tty_port *port);
 598 extern void tty_port_put(struct tty_port *port);
 599
 600 static inline struct tty_port *tty_port_get(struct tty_port *port)
 601 {
 602         if (port && kref_get_unless_zero(&port->kref))
 603                 return port;
 604         return NULL;
 605 }
 606
 607 /* If the cts flow control is enabled, return true. */
 608 static inline bool tty_port_cts_enabled(struct tty_port *port)
 609 {
 610         return test_bit(TTY_PORT_CTS_FLOW, &port->iflags);
 611 }
 612
 613 static inline void tty_port_set_cts_flow(struct tty_port *port, bool val)
 614 {
 615         if (val)
 616                 set_bit(TTY_PORT_CTS_FLOW, &port->iflags);
 617         else
 618                 clear_bit(TTY_PORT_CTS_FLOW, &port->iflags);
 619 }
 620
 621 static inline bool tty_port_active(struct tty_port *port)
 622 {
 623         return test_bit(TTY_PORT_ACTIVE, &port->iflags);
 624 }
 625
 626 static inline void tty_port_set_active(struct tty_port *port, bool val)
 627 {
 628         if (val)
 629                 set_bit(TTY_PORT_ACTIVE, &port->iflags);
 630         else
 631                 clear_bit(TTY_PORT_ACTIVE, &port->iflags);
 632 }
 633
 634 static inline bool tty_port_check_carrier(struct tty_port *port)
 635 {
 636         return test_bit(TTY_PORT_CHECK_CD, &port->iflags);
 637 }
 638
 639 static inline void tty_port_set_check_carrier(struct tty_port *port, bool val)
 640 {
 641         if (val)
 642                 set_bit(TTY_PORT_CHECK_CD, &port->iflags);
 643         else
 644                 clear_bit(TTY_PORT_CHECK_CD, &port->iflags);
 645 }
 646
 647 static inline bool tty_port_suspended(struct tty_port *port)
 648 {
 649         return test_bit(TTY_PORT_SUSPENDED, &port->iflags);
 650 }
 651
 652 static inline void tty_port_set_suspended(struct tty_port *port, bool val)
 653 {
 654         if (val)
 655                 set_bit(TTY_PORT_SUSPENDED, &port->iflags);
 656         else
 657                 clear_bit(TTY_PORT_SUSPENDED, &port->iflags);
 658 }
 659
 660 static inline bool tty_port_initialized(struct tty_port *port)
 661 {
 662         return test_bit(TTY_PORT_INITIALIZED, &port->iflags);
 663 }
 664
 665 static inline void tty_port_set_initialized(struct tty_port *port, bool val)
 666 {
 667         if (val)
 668                 set_bit(TTY_PORT_INITIALIZED, &port->iflags);
 669         else
 670                 clear_bit(TTY_PORT_INITIALIZED, &port->iflags);
 671 }
 672
 673 static inline bool tty_port_kopened(struct tty_port *port)
 674 {
 675         return test_bit(TTY_PORT_KOPENED, &port->iflags);
 676 }
 677
 678 static inline void tty_port_set_kopened(struct tty_port *port, bool val)
 679 {
 680         if (val)
 681                 set_bit(TTY_PORT_KOPENED, &port->iflags);
 682         else
 683                 clear_bit(TTY_PORT_KOPENED, &port->iflags);
 684 }
 685
 686 extern struct tty_struct *tty_port_tty_get(struct tty_port *port);
 687 extern void tty_port_tty_set(struct tty_port *port, struct tty_struct *tty);
 688 extern int tty_port_carrier_raised(struct tty_port *port);
 689 extern void tty_port_raise_dtr_rts(struct tty_port *port);
 690 extern void tty_port_lower_dtr_rts(struct tty_port *port);
 691 extern void tty_port_hangup(struct tty_port *port);
 692 extern void tty_port_tty_hangup(struct tty_port *port, bool check_clocal);
 693 extern void tty_port_tty_wakeup(struct tty_port *port);
 694 extern int tty_port_block_til_ready(struct tty_port *port,
 695                                 struct tty_struct *tty, struct file *filp);
 696 extern int tty_port_close_start(struct tty_port *port,
 697                                 struct tty_struct *tty, struct file *filp);
 698 extern void tty_port_close_end(struct tty_port *port, struct tty_struct *tty);
 699 extern void tty_port_close(struct tty_port *port,
 700                                 struct tty_struct *tty, struct file *filp);
 701 extern int tty_port_install(struct tty_port *port, struct tty_driver *driver,
 702                                 struct tty_struct *tty);
 703 extern int tty_port_open(struct tty_port *port,
 704                                 struct tty_struct *tty, struct file *filp);
 705 static inline int tty_port_users(struct tty_port *port)
 706 {
 707         return port->count + port->blocked_open;
 708 }
 709
 710 extern int tty_register_ldisc(int disc, struct tty_ldisc_ops *new_ldisc);
 711 extern int tty_unregister_ldisc(int disc);
 712 extern int tty_set_ldisc(struct tty_struct *tty, int disc);
 713 extern int tty_ldisc_setup(struct tty_struct *tty, struct tty_struct *o_tty);
 714 extern void tty_ldisc_release(struct tty_struct *tty);
 715 extern int __must_check tty_ldisc_init(struct tty_struct *tty);
 716 extern void tty_ldisc_deinit(struct tty_struct *tty);
 717 extern int tty_ldisc_receive_buf(struct tty_ldisc *ld, const unsigned char *p,
 718                                  char *f, int count);
 719
 720 /* n_tty.c */
 721 extern void n_tty_inherit_ops(struct tty_ldisc_ops *ops);
 722 #ifdef CONFIG_TTY
 723 extern void __init n_tty_init(void);
 724 #else
 725 static inline void n_tty_init(void) { }
 726 #endif
 727
 728 /* tty_audit.c */
 729 #ifdef CONFIG_AUDIT
 730 extern void tty_audit_add_data(struct tty_struct *tty, const void *data,
 731                                size_t size);
 732 extern void tty_audit_exit(void);
 733 extern void tty_audit_fork(struct signal_struct *sig);
 734 extern void tty_audit_tiocsti(struct tty_struct *tty, char ch);
 735 extern int tty_audit_push(void);
 736 #else
 737 static inline void tty_audit_add_data(struct tty_struct *tty, const void *data,
 738                                       size_t size)
 739 {
 740 }
 741 static inline void tty_audit_tiocsti(struct tty_struct *tty, char ch)
 742 {
 743 }
 744 static inline void tty_audit_exit(void)
 745 {
 746 }
 747 static inline void tty_audit_fork(struct signal_struct *sig)
 748 {
 749 }
 750 static inline int tty_audit_push(void)
 751 {
 752         return 0;
 753 }
 754 #endif
 755
 756 /* tty_ioctl.c */
 757 extern int n_tty_ioctl_helper(struct tty_struct *tty, struct file *file,
 758                        unsigned int cmd, unsigned long arg);
 759
 760 /* vt.c */
 761
 762 extern int vt_ioctl(struct tty_struct *tty,
 763                     unsigned int cmd, unsigned long arg);
 764
 765 extern long vt_compat_ioctl(struct tty_struct *tty,
 766                      unsigned int cmd, unsigned long arg);
 767
 768 /* tty_mutex.c */
 769 /* functions for preparation of BKL removal */
 770 extern void tty_lock(struct tty_struct *tty);
 771 extern int  tty_lock_interruptible(struct tty_struct *tty);
 772 extern void tty_unlock(struct tty_struct *tty);
 773 extern void tty_lock_slave(struct tty_struct *tty);
 774 extern void tty_unlock_slave(struct tty_struct *tty);
 775 extern void tty_set_lock_subclass(struct tty_struct *tty);
 776
 777 #ifdef CONFIG_PROC_FS
 778 extern void proc_tty_register_driver(struct tty_driver *);
 779 extern void proc_tty_unregister_driver(struct tty_driver *);
 780 #else
 781 static inline void proc_tty_register_driver(struct tty_driver *d) {}
 782 static inline void proc_tty_unregister_driver(struct tty_driver *d) {}
 783 #endif
 784
 785 #define tty_msg(fn, tty, f, ...) \
 786         fn("%s %s: " f, tty_driver_name(tty), tty_name(tty), ##__VA_ARGS__)
 787
 788 #define tty_debug(tty, f, ...)  tty_msg(pr_debug, tty, f, ##__VA_ARGS__)
 789 #define tty_info(tty, f, ...)   tty_msg(pr_info, tty, f, ##__VA_ARGS__)
 790 #define tty_notice(tty, f, ...) tty_msg(pr_notice, tty, f, ##__VA_ARGS__)
 791 #define tty_warn(tty, f, ...)   tty_msg(pr_warn, tty, f, ##__VA_ARGS__)
 792 #define tty_err(tty, f, ...)    tty_msg(pr_err, tty, f, ##__VA_ARGS__)
 793
 794 #define tty_info_ratelimited(tty, f, ...) \
 795                 tty_msg(pr_info_ratelimited, tty, f, ##__VA_ARGS__)
 796
 797 #endif