LXR linux/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
 118struct device;
 119struct signal_struct;
 120struct 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 */
 143struct 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 */
 208struct 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
 238static 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
 244static inline bool tty_io_error(struct tty_struct *tty)
 245{
 246        return test_bit(TTY_IO_ERROR, &tty->flags);
 247}
 248
 249static inline bool tty_throttled(struct tty_struct *tty)
 250{
 251        return test_bit(TTY_THROTTLED, &tty->flags);
 252}
 253
 254#ifdef CONFIG_TTY
 255extern void tty_kref_put(struct tty_struct *tty);
 256extern struct pid *tty_get_pgrp(struct tty_struct *tty);
 257extern void tty_vhangup_self(void);
 258extern void disassociate_ctty(int priv);
 259extern dev_t tty_devnum(struct tty_struct *tty);
 260extern void proc_clear_tty(struct task_struct *p);
 261extern struct tty_struct *get_current_tty(void);
 262/* tty_io.c */
 263extern int __init tty_init(void);
 264extern const char *tty_name(const struct tty_struct *tty);
 265extern struct tty_struct *tty_kopen_exclusive(dev_t device);
 266extern struct tty_struct *tty_kopen_shared(dev_t device);
 267extern void tty_kclose(struct tty_struct *tty);
 268extern int tty_dev_name_to_number(const char *name, dev_t *number);
 269#else
 270static inline void tty_kref_put(struct tty_struct *tty)
 271{ }
 272static inline struct pid *tty_get_pgrp(struct tty_struct *tty)
 273{ return NULL; }
 274static inline void tty_vhangup_self(void)
 275{ }
 276static inline void disassociate_ctty(int priv)
 277{ }
 278static inline dev_t tty_devnum(struct tty_struct *tty)
 279{ return 0; }
 280static inline void proc_clear_tty(struct task_struct *p)
 281{ }
 282static inline struct tty_struct *get_current_tty(void)
 283{ return NULL; }
 284/* tty_io.c */
 285static inline int __init tty_init(void)
 286{ return 0; }
 287static inline const char *tty_name(const struct tty_struct *tty)
 288{ return "(none)"; }
 289static inline struct tty_struct *tty_kopen_exclusive(dev_t device)
 290{ return ERR_PTR(-ENODEV); }
 291static inline void tty_kclose(struct tty_struct *tty)
 292{ }
 293static inline int tty_dev_name_to_number(const char *name, dev_t *number)
 294{ return -ENOTSUPP; }
 295#endif
 296
 297extern struct ktermios tty_std_termios;
 298
 299extern int vcs_init(void);
 300
 301extern 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
 312static 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
 319extern const char *tty_driver_name(const struct tty_struct *tty);
 320extern void tty_wait_until_sent(struct tty_struct *tty, long timeout);
 321extern void stop_tty(struct tty_struct *tty);
 322extern void start_tty(struct tty_struct *tty);
 323extern void tty_write_message(struct tty_struct *tty, char *msg);
 324extern int tty_send_xchar(struct tty_struct *tty, char ch);
 325extern int tty_put_char(struct tty_struct *tty, unsigned char c);
 326extern unsigned int tty_chars_in_buffer(struct tty_struct *tty);
 327extern unsigned int tty_write_room(struct tty_struct *tty);
 328extern void tty_driver_flush_buffer(struct tty_struct *tty);
 329extern void tty_unthrottle(struct tty_struct *tty);
 330extern int tty_throttle_safe(struct tty_struct *tty);
 331extern int tty_unthrottle_safe(struct tty_struct *tty);
 332extern int tty_do_resize(struct tty_struct *tty, struct winsize *ws);
 333extern int tty_get_icount(struct tty_struct *tty,
 334                          struct serial_icounter_struct *icount);
 335extern int is_current_pgrp_orphaned(void);
 336extern void tty_hangup(struct tty_struct *tty);
 337extern void tty_vhangup(struct tty_struct *tty);
 338extern int tty_hung_up_p(struct file *filp);
 339extern void do_SAK(struct tty_struct *tty);
 340extern void __do_SAK(struct tty_struct *tty);
 341extern void no_tty(void);
 342extern speed_t tty_termios_baud_rate(struct ktermios *termios);
 343extern void tty_termios_encode_baud_rate(struct ktermios *termios,
 344                                                speed_t ibaud, speed_t obaud);
 345extern 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 */
 358static inline speed_t tty_get_baud_rate(struct tty_struct *tty)
 359{
 360        return tty_termios_baud_rate(&tty->termios);
 361}
 362
 363unsigned char tty_get_char_size(unsigned int cflag);
 364unsigned char tty_get_frame_size(unsigned int cflag);
 365
 366extern void tty_termios_copy_hw(struct ktermios *new, struct ktermios *old);
 367extern int tty_termios_hw_change(const struct ktermios *a, const struct ktermios *b);
 368extern int tty_set_termios(struct tty_struct *tty, struct ktermios *kt);
 369
 370extern void tty_wakeup(struct tty_struct *tty);
 371
 372extern int tty_mode_ioctl(struct tty_struct *tty, struct file *file,
 373                        unsigned int cmd, unsigned long arg);
 374extern int tty_perform_flush(struct tty_struct *tty, unsigned long arg);
 375extern struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx);
 376extern void tty_release_struct(struct tty_struct *tty, int idx);
 377extern void tty_init_termios(struct tty_struct *tty);
 378extern void tty_save_termios(struct tty_struct *tty);
 379extern int tty_standard_install(struct tty_driver *driver,
 380                struct tty_struct *tty);
 381
 382extern struct mutex tty_mutex;
 383
 384/* n_tty.c */
 385extern void n_tty_inherit_ops(struct tty_ldisc_ops *ops);
 386#ifdef CONFIG_TTY
 387extern void __init n_tty_init(void);
 388#else
 389static inline void n_tty_init(void) { }
 390#endif
 391
 392/* tty_audit.c */
 393#ifdef CONFIG_AUDIT
 394extern void tty_audit_exit(void);
 395extern void tty_audit_fork(struct signal_struct *sig);
 396extern int tty_audit_push(void);
 397#else
 398static inline void tty_audit_exit(void)
 399{
 400}
 401static inline void tty_audit_fork(struct signal_struct *sig)
 402{
 403}
 404static inline int tty_audit_push(void)
 405{
 406        return 0;
 407}
 408#endif
 409
 410/* tty_ioctl.c */
 411extern int n_tty_ioctl_helper(struct tty_struct *tty, struct file *file,
 412                       unsigned int cmd, unsigned long arg);
 413
 414/* vt.c */
 415
 416extern int vt_ioctl(struct tty_struct *tty,
 417                    unsigned int cmd, unsigned long arg);
 418
 419extern 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 */
 424extern void tty_lock(struct tty_struct *tty);
 425extern int  tty_lock_interruptible(struct tty_struct *tty);
 426extern void tty_unlock(struct tty_struct *tty);
 427extern void tty_lock_slave(struct tty_struct *tty);
 428extern void tty_unlock_slave(struct tty_struct *tty);
 429extern void tty_set_lock_subclass(struct tty_struct *tty);
 430
 431#endif
 432