tty.h

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#ifndef _LINUX_TTY_H
#define _LINUX_TTY_H

#include <linux/fs.h>
#include <linux/major.h>
#include <linux/termios.h>
#include <linux/workqueue.h>
#include <linux/tty_driver.h>
#include <linux/tty_ldisc.h>
#include <linux/mutex.h>
#include <linux/tty_flags.h>
#include <uapi/linux/tty.h>



/*
 * (Note: the *_driver.minor_start values 1, 64, 128, 192 are
 * hardcoded at present.)
 */
#define NR_UNIX98_PTY_DEFAULT   4096      /* Default maximum for Unix98 ptys */
#define NR_UNIX98_PTY_RESERVE   1024      /* Default reserve for main devpts */
#define NR_UNIX98_PTY_MAX   (1 << MINORBITS) /* Absolute limit */

/*
 * This character is the same as _POSIX_VDISABLE: it cannot be used as
 * a c_cc[] character, but indicates that a particular special character
 * isn't in use (eg VINTR has no character etc)
 */
#define __DISABLED_CHAR '\0'

struct tty_buffer {
    struct tty_buffer *next;
    char *char_buf_ptr;
    unsigned char *flag_buf_ptr;
    int used;
    int size;
    int commit;
    int read;
    /* Data points here */
    unsigned long data[0];
};

/*
 * We default to dicing tty buffer allocations to this many characters
 * in order to avoid multiple page allocations. We know the size of
 * tty_buffer itself but it must also be taken into account that the
 * the buffer is 256 byte aligned. See tty_buffer_find for the allocation
 * logic this must match
 */

#define TTY_BUFFER_PAGE (((PAGE_SIZE - sizeof(struct tty_buffer)) / 2) & ~0xFF)


struct tty_bufhead {
    struct work_struct work;
    spinlock_t lock;
    struct tty_buffer *head;    /* Queue head */
    struct tty_buffer *tail;    /* Active buffer */
    struct tty_buffer *free;    /* Free queue head */
    int memory_used;        /* Buffer space used excluding
                                free queue */
};
/*
 * When a break, frame error, or parity error happens, these codes are
 * stuffed into the flags buffer.
 */
#define TTY_NORMAL  0
#define TTY_BREAK   1
#define TTY_FRAME   2
#define TTY_PARITY  3
#define TTY_OVERRUN 4

#define INTR_CHAR(tty) ((tty)->termios.c_cc[VINTR])
#define QUIT_CHAR(tty) ((tty)->termios.c_cc[VQUIT])
#define ERASE_CHAR(tty) ((tty)->termios.c_cc[VERASE])
#define KILL_CHAR(tty) ((tty)->termios.c_cc[VKILL])
#define EOF_CHAR(tty) ((tty)->termios.c_cc[VEOF])
#define TIME_CHAR(tty) ((tty)->termios.c_cc[VTIME])
#define MIN_CHAR(tty) ((tty)->termios.c_cc[VMIN])
#define SWTC_CHAR(tty) ((tty)->termios.c_cc[VSWTC])
#define START_CHAR(tty) ((tty)->termios.c_cc[VSTART])
#define STOP_CHAR(tty) ((tty)->termios.c_cc[VSTOP])
#define SUSP_CHAR(tty) ((tty)->termios.c_cc[VSUSP])
#define EOL_CHAR(tty) ((tty)->termios.c_cc[VEOL])
#define REPRINT_CHAR(tty) ((tty)->termios.c_cc[VREPRINT])
#define DISCARD_CHAR(tty) ((tty)->termios.c_cc[VDISCARD])
#define WERASE_CHAR(tty) ((tty)->termios.c_cc[VWERASE])
#define LNEXT_CHAR(tty) ((tty)->termios.c_cc[VLNEXT])
#define EOL2_CHAR(tty) ((tty)->termios.c_cc[VEOL2])

#define _I_FLAG(tty, f) ((tty)->termios.c_iflag & (f))
#define _O_FLAG(tty, f) ((tty)->termios.c_oflag & (f))
#define _C_FLAG(tty, f) ((tty)->termios.c_cflag & (f))
#define _L_FLAG(tty, f) ((tty)->termios.c_lflag & (f))

#define I_IGNBRK(tty)   _I_FLAG((tty), IGNBRK)
#define I_BRKINT(tty)   _I_FLAG((tty), BRKINT)
#define I_IGNPAR(tty)   _I_FLAG((tty), IGNPAR)
#define I_PARMRK(tty)   _I_FLAG((tty), PARMRK)
#define I_INPCK(tty)    _I_FLAG((tty), INPCK)
#define I_ISTRIP(tty)   _I_FLAG((tty), ISTRIP)
#define I_INLCR(tty)    _I_FLAG((tty), INLCR)
#define I_IGNCR(tty)    _I_FLAG((tty), IGNCR)
#define I_ICRNL(tty)    _I_FLAG((tty), ICRNL)
#define I_IUCLC(tty)    _I_FLAG((tty), IUCLC)
#define I_IXON(tty) _I_FLAG((tty), IXON)
#define I_IXANY(tty)    _I_FLAG((tty), IXANY)
#define I_IXOFF(tty)    _I_FLAG((tty), IXOFF)
#define I_IMAXBEL(tty)  _I_FLAG((tty), IMAXBEL)
#define I_IUTF8(tty)    _I_FLAG((tty), IUTF8)

#define O_OPOST(tty)    _O_FLAG((tty), OPOST)
#define O_OLCUC(tty)    _O_FLAG((tty), OLCUC)
#define O_ONLCR(tty)    _O_FLAG((tty), ONLCR)
#define O_OCRNL(tty)    _O_FLAG((tty), OCRNL)
#define O_ONOCR(tty)    _O_FLAG((tty), ONOCR)
#define O_ONLRET(tty)   _O_FLAG((tty), ONLRET)
#define O_OFILL(tty)    _O_FLAG((tty), OFILL)
#define O_OFDEL(tty)    _O_FLAG((tty), OFDEL)
#define O_NLDLY(tty)    _O_FLAG((tty), NLDLY)
#define O_CRDLY(tty)    _O_FLAG((tty), CRDLY)
#define O_TABDLY(tty)   _O_FLAG((tty), TABDLY)
#define O_BSDLY(tty)    _O_FLAG((tty), BSDLY)
#define O_VTDLY(tty)    _O_FLAG((tty), VTDLY)
#define O_FFDLY(tty)    _O_FLAG((tty), FFDLY)

#define C_BAUD(tty) _C_FLAG((tty), CBAUD)
#define C_CSIZE(tty)    _C_FLAG((tty), CSIZE)
#define C_CSTOPB(tty)   _C_FLAG((tty), CSTOPB)
#define C_CREAD(tty)    _C_FLAG((tty), CREAD)
#define C_PARENB(tty)   _C_FLAG((tty), PARENB)
#define C_PARODD(tty)   _C_FLAG((tty), PARODD)
#define C_HUPCL(tty)    _C_FLAG((tty), HUPCL)
#define C_CLOCAL(tty)   _C_FLAG((tty), CLOCAL)
#define C_CIBAUD(tty)   _C_FLAG((tty), CIBAUD)
#define C_CRTSCTS(tty)  _C_FLAG((tty), CRTSCTS)

#define L_ISIG(tty) _L_FLAG((tty), ISIG)
#define L_ICANON(tty)   _L_FLAG((tty), ICANON)
#define L_XCASE(tty)    _L_FLAG((tty), XCASE)
#define L_ECHO(tty) _L_FLAG((tty), ECHO)
#define L_ECHOE(tty)    _L_FLAG((tty), ECHOE)
#define L_ECHOK(tty)    _L_FLAG((tty), ECHOK)
#define L_ECHONL(tty)   _L_FLAG((tty), ECHONL)
#define L_NOFLSH(tty)   _L_FLAG((tty), NOFLSH)
#define L_TOSTOP(tty)   _L_FLAG((tty), TOSTOP)
#define L_ECHOCTL(tty)  _L_FLAG((tty), ECHOCTL)
#define L_ECHOPRT(tty)  _L_FLAG((tty), ECHOPRT)
#define L_ECHOKE(tty)   _L_FLAG((tty), ECHOKE)
#define L_FLUSHO(tty)   _L_FLAG((tty), FLUSHO)
#define L_PENDIN(tty)   _L_FLAG((tty), PENDIN)
#define L_IEXTEN(tty)   _L_FLAG((tty), IEXTEN)
#define L_EXTPROC(tty)  _L_FLAG((tty), EXTPROC)

struct device;
struct signal_struct;

/*
 * Port level information. Each device keeps its own port level information
 * so provide a common structure for those ports wanting to use common support
 * routines.
 *
 * The tty port has a different lifetime to the tty so must be kept apart.
 * In addition be careful as tty -> port mappings are valid for the life
 * of the tty object but in many cases port -> tty mappings are valid only
 * until a hangup so don't use the wrong path.
 */

struct tty_port;

struct tty_port_operations {
    /* Return 1 if the carrier is raised */
    int (*carrier_raised)(struct tty_port *port);
    /* Control the DTR line */
    void (*dtr_rts)(struct tty_port *port, int raise);
    /* Called when the last close completes or a hangup finishes
       IFF the port was initialized. Do not use to free resources. Called
       under the port mutex to serialize against activate/shutdowns */
    void (*shutdown)(struct tty_port *port);
    void (*drop)(struct tty_port *port);
    /* Called under the port mutex from tty_port_open, serialized using
       the port mutex */
        /* FIXME: long term getting the tty argument *out* of this would be
           good for consoles */
    int (*activate)(struct tty_port *port, struct tty_struct *tty);
    /* Called on the final put of a port */
    void (*destruct)(struct tty_port *port);
};
    
struct tty_port {
    struct tty_struct   *tty;       /* Back pointer */
    const struct tty_port_operations *ops;  /* Port operations */
    spinlock_t      lock;       /* Lock protecting tty field */
    int         blocked_open;   /* Waiting to open */
    int         count;      /* Usage count */
    wait_queue_head_t   open_wait;  /* Open waiters */
    wait_queue_head_t   close_wait; /* Close waiters */
    wait_queue_head_t   delta_msr_wait; /* Modem status change */
    unsigned long       flags;      /* TTY flags ASY_*/
    unsigned char       console:1;  /* port is a console */
    struct mutex        mutex;      /* Locking */
    struct mutex        buf_mutex;  /* Buffer alloc lock */
    unsigned char       *xmit_buf;  /* Optional buffer */
    unsigned int        close_delay;    /* Close port delay */
    unsigned int        closing_wait;   /* Delay for output */
    int         drain_delay;    /* Set to zero if no pure time
                           based drain is needed else
                           set to size of fifo */
    struct kref     kref;       /* Ref counter */
};

/*
 * Where all of the state associated with a tty is kept while the tty
 * is open.  Since the termios state should be kept even if the tty
 * has been closed --- for things like the baud rate, etc --- it is
 * not stored here, but rather a pointer to the real state is stored
 * here.  Possible the winsize structure should have the same
 * treatment, but (1) the default 80x24 is usually right and (2) it's
 * most often used by a windowing system, which will set the correct
 * size each time the window is created or resized anyway.
 *                      - TYT, 9/14/92
 */

struct tty_operations;

struct tty_struct {
    int magic;
    struct kref kref;
    struct device *dev;
    struct tty_driver *driver;
    const struct tty_operations *ops;
    int index;

    /* Protects ldisc changes: Lock tty not pty */
    struct mutex ldisc_mutex;
    struct tty_ldisc *ldisc;

    struct mutex legacy_mutex;
    struct mutex termios_mutex;
    spinlock_t ctrl_lock;
    /* Termios values are protected by the termios mutex */
    struct ktermios termios, termios_locked;
    struct termiox *termiox;    /* May be NULL for unsupported */
    char name[64];
    struct pid *pgrp;       /* Protected by ctrl lock */
    struct pid *session;
    unsigned long flags;
    int count;
    struct winsize winsize;     /* termios mutex */
    unsigned char stopped:1, hw_stopped:1, flow_stopped:1, packet:1;
    unsigned char low_latency:1, warned:1;
    unsigned char ctrl_status;  /* ctrl_lock */
    unsigned int receive_room;  /* Bytes free for queue */

    struct tty_struct *link;
    struct fasync_struct *fasync;
    struct tty_bufhead buf;     /* Locked internally */
    int alt_speed;      /* For magic substitution of 38400 bps */
    wait_queue_head_t write_wait;
    wait_queue_head_t read_wait;
    struct work_struct hangup_work;
    void *disc_data;
    void *driver_data;
    struct list_head tty_files;

#define N_TTY_BUF_SIZE 4096

    /*
     * The following is data for the N_TTY line discipline.  For
     * historical reasons, this is included in the tty structure.
     * Mostly locked by the BKL.
     */
    unsigned int column;
    unsigned char lnext:1, erasing:1, raw:1, real_raw:1, icanon:1;
    unsigned char closing:1;
    unsigned char echo_overrun:1;
    unsigned short minimum_to_wake;
    unsigned long overrun_time;
    int num_overrun;
    unsigned long process_char_map[256/(8*sizeof(unsigned long))];
    char *read_buf;
    int read_head;
    int read_tail;
    int read_cnt;
    unsigned long read_flags[N_TTY_BUF_SIZE/(8*sizeof(unsigned long))];
    unsigned char *echo_buf;
    unsigned int echo_pos;
    unsigned int echo_cnt;
    int canon_data;
    unsigned long canon_head;
    unsigned int canon_column;
    struct mutex atomic_read_lock;
    struct mutex atomic_write_lock;
    struct mutex output_lock;
    struct mutex echo_lock;
    unsigned char *write_buf;
    int write_cnt;
    spinlock_t read_lock;
    /* If the tty has a pending do_SAK, queue it here - akpm */
    struct work_struct SAK_work;
    struct tty_port *port;
};

/* Each of a tty's open files has private_data pointing to tty_file_private */
struct tty_file_private {
    struct tty_struct *tty;
    struct file *file;
    struct list_head list;
};

/* tty magic number */
#define TTY_MAGIC       0x5401

/*
 * These bits are used in the flags field of the tty structure.
 *
 * So that interrupts won't be able to mess up the queues,
 * copy_to_cooked must be atomic with respect to itself, as must
 * tty->write.  Thus, you must use the inline functions set_bit() and
 * clear_bit() to make things atomic.
 */
#define TTY_THROTTLED       0   /* Call unthrottle() at threshold min */
#define TTY_IO_ERROR        1   /* Cause an I/O error (may be no ldisc too) */
#define TTY_OTHER_CLOSED    2   /* Other side (if any) has closed */
#define TTY_EXCLUSIVE       3   /* Exclusive open mode */
#define TTY_DEBUG       4   /* Debugging */
#define TTY_DO_WRITE_WAKEUP     5   /* Call write_wakeup after queuing new */
#define TTY_PUSH        6   /* n_tty private */
#define TTY_CLOSING         7   /* ->close() in progress */
#define TTY_LDISC       9   /* Line discipline attached */
#define TTY_LDISC_CHANGING  10  /* Line discipline changing */
#define TTY_LDISC_OPEN      11  /* Line discipline is open */
#define TTY_HW_COOK_OUT     14  /* Hardware can do output cooking */
#define TTY_HW_COOK_IN      15  /* Hardware can do input cooking */
#define TTY_PTY_LOCK        16  /* pty private */
#define TTY_NO_WRITE_SPLIT  17  /* Preserve write boundaries to driver */
#define TTY_HUPPED      18  /* Post driver->hangup() */
#define TTY_FLUSHING        19  /* Flushing to ldisc in progress */
#define TTY_FLUSHPENDING    20  /* Queued buffer flush pending */
#define TTY_HUPPING         21  /* ->hangup() in progress */

#define TTY_WRITE_FLUSH(tty) tty_write_flush((tty))

extern void tty_write_flush(struct tty_struct *);

extern struct ktermios tty_std_termios;

extern void console_init(void);
extern int vcs_init(void);

extern struct class *tty_class;

static inline struct tty_struct *tty_kref_get(struct tty_struct *tty)
{
    if (tty)
        kref_get(&tty->kref);
    return tty;
}
extern void tty_kref_put(struct tty_struct *tty);

extern int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
                  const char *routine);
extern char *tty_name(struct tty_struct *tty, char *buf);
extern void tty_wait_until_sent(struct tty_struct *tty, long timeout);
extern int tty_check_change(struct tty_struct *tty);
extern void stop_tty(struct tty_struct *tty);
extern void start_tty(struct tty_struct *tty);
extern int tty_register_driver(struct tty_driver *driver);
extern int tty_unregister_driver(struct tty_driver *driver);
extern struct device *tty_register_device(struct tty_driver *driver,
                      unsigned index, struct device *dev);
extern struct device *tty_register_device_attr(struct tty_driver *driver,
                unsigned index, struct device *device,
                void *drvdata,
                const struct attribute_group **attr_grp);
extern void tty_unregister_device(struct tty_driver *driver, unsigned index);
extern int tty_read_raw_data(struct tty_struct *tty, unsigned char *bufp,
                 int buflen);
extern void tty_write_message(struct tty_struct *tty, char *msg);
extern int tty_put_char(struct tty_struct *tty, unsigned char c);
extern int tty_chars_in_buffer(struct tty_struct *tty);
extern int tty_write_room(struct tty_struct *tty);
extern void tty_driver_flush_buffer(struct tty_struct *tty);
extern void tty_throttle(struct tty_struct *tty);
extern void tty_unthrottle(struct tty_struct *tty);
extern int tty_do_resize(struct tty_struct *tty, struct winsize *ws);
extern void tty_driver_remove_tty(struct tty_driver *driver,
                  struct tty_struct *tty);
extern void tty_free_termios(struct tty_struct *tty);
extern int is_current_pgrp_orphaned(void);
extern struct pid *tty_get_pgrp(struct tty_struct *tty);
extern int is_ignored(int sig);
extern int tty_signal(int sig, struct tty_struct *tty);
extern void tty_hangup(struct tty_struct *tty);
extern void tty_vhangup(struct tty_struct *tty);
extern void tty_vhangup_locked(struct tty_struct *tty);
extern void tty_vhangup_self(void);
extern void tty_unhangup(struct file *filp);
extern int tty_hung_up_p(struct file *filp);
extern void do_SAK(struct tty_struct *tty);
extern void __do_SAK(struct tty_struct *tty);
extern void disassociate_ctty(int priv);
extern void no_tty(void);
extern void tty_flip_buffer_push(struct tty_struct *tty);
extern void tty_flush_to_ldisc(struct tty_struct *tty);
extern void tty_buffer_free_all(struct tty_struct *tty);
extern void tty_buffer_flush(struct tty_struct *tty);
extern void tty_buffer_init(struct tty_struct *tty);
extern speed_t tty_get_baud_rate(struct tty_struct *tty);
extern speed_t tty_termios_baud_rate(struct ktermios *termios);
extern speed_t tty_termios_input_baud_rate(struct ktermios *termios);
extern void tty_termios_encode_baud_rate(struct ktermios *termios,
                        speed_t ibaud, speed_t obaud);
extern void tty_encode_baud_rate(struct tty_struct *tty,
                        speed_t ibaud, speed_t obaud);
extern void tty_termios_copy_hw(struct ktermios *new, struct ktermios *old);
extern int tty_termios_hw_change(struct ktermios *a, struct ktermios *b);
extern int tty_set_termios(struct tty_struct *tty, struct ktermios *kt);

extern struct tty_ldisc *tty_ldisc_ref(struct tty_struct *);
extern void tty_ldisc_deref(struct tty_ldisc *);
extern struct tty_ldisc *tty_ldisc_ref_wait(struct tty_struct *);
extern void tty_ldisc_hangup(struct tty_struct *tty);
extern const struct file_operations tty_ldiscs_proc_fops;

extern void tty_wakeup(struct tty_struct *tty);
extern void tty_ldisc_flush(struct tty_struct *tty);

extern long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
extern int tty_mode_ioctl(struct tty_struct *tty, struct file *file,
            unsigned int cmd, unsigned long arg);
extern int tty_perform_flush(struct tty_struct *tty, unsigned long arg);
extern dev_t tty_devnum(struct tty_struct *tty);
extern void proc_clear_tty(struct task_struct *p);
extern struct tty_struct *get_current_tty(void);
extern void tty_default_fops(struct file_operations *fops);
extern struct tty_struct *alloc_tty_struct(void);
extern int tty_alloc_file(struct file *file);
extern void tty_add_file(struct tty_struct *tty, struct file *file);
extern void tty_free_file(struct file *file);
extern void free_tty_struct(struct tty_struct *tty);
extern void initialize_tty_struct(struct tty_struct *tty,
        struct tty_driver *driver, int idx);
extern void deinitialize_tty_struct(struct tty_struct *tty);
extern struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx);
extern int tty_release(struct inode *inode, struct file *filp);
extern int tty_init_termios(struct tty_struct *tty);
extern int tty_standard_install(struct tty_driver *driver,
        struct tty_struct *tty);

extern struct tty_struct *tty_pair_get_tty(struct tty_struct *tty);
extern struct tty_struct *tty_pair_get_pty(struct tty_struct *tty);

extern struct mutex tty_mutex;
extern spinlock_t tty_files_lock;

extern void tty_write_unlock(struct tty_struct *tty);
extern int tty_write_lock(struct tty_struct *tty, int ndelay);
#define tty_is_writelocked(tty)  (mutex_is_locked(&tty->atomic_write_lock))

extern void tty_port_init(struct tty_port *port);
extern void tty_port_link_device(struct tty_port *port,
        struct tty_driver *driver, unsigned index);
extern struct device *tty_port_register_device(struct tty_port *port,
        struct tty_driver *driver, unsigned index,
        struct device *device);
extern struct device *tty_port_register_device_attr(struct tty_port *port,
        struct tty_driver *driver, unsigned index,
        struct device *device, void *drvdata,
        const struct attribute_group **attr_grp);
extern int tty_port_alloc_xmit_buf(struct tty_port *port);
extern void tty_port_free_xmit_buf(struct tty_port *port);
extern void tty_port_put(struct tty_port *port);

static inline struct tty_port *tty_port_get(struct tty_port *port)
{
    if (port)
        kref_get(&port->kref);
    return port;
}

/* If the cts flow control is enabled, return true. */
static inline bool tty_port_cts_enabled(struct tty_port *port)
{
    return port->flags & ASYNC_CTS_FLOW;
}

extern struct tty_struct *tty_port_tty_get(struct tty_port *port);
extern void tty_port_tty_set(struct tty_port *port, struct tty_struct *tty);
extern int tty_port_carrier_raised(struct tty_port *port);
extern void tty_port_raise_dtr_rts(struct tty_port *port);
extern void tty_port_lower_dtr_rts(struct tty_port *port);
extern void tty_port_hangup(struct tty_port *port);
extern int tty_port_block_til_ready(struct tty_port *port,
                struct tty_struct *tty, struct file *filp);
extern int tty_port_close_start(struct tty_port *port,
                struct tty_struct *tty, struct file *filp);
extern void tty_port_close_end(struct tty_port *port, struct tty_struct *tty);
extern void tty_port_close(struct tty_port *port,
                struct tty_struct *tty, struct file *filp);
extern int tty_port_install(struct tty_port *port, struct tty_driver *driver,
                struct tty_struct *tty);
extern int tty_port_open(struct tty_port *port,
                struct tty_struct *tty, struct file *filp);
static inline int tty_port_users(struct tty_port *port)
{
    return port->count + port->blocked_open;
}

extern int tty_register_ldisc(int disc, struct tty_ldisc_ops *new_ldisc);
extern int tty_unregister_ldisc(int disc);
extern int tty_set_ldisc(struct tty_struct *tty, int ldisc);
extern int tty_ldisc_setup(struct tty_struct *tty, struct tty_struct *o_tty);
extern void tty_ldisc_release(struct tty_struct *tty, struct tty_struct *o_tty);
extern void tty_ldisc_init(struct tty_struct *tty);
extern void tty_ldisc_deinit(struct tty_struct *tty);
extern void tty_ldisc_begin(void);
/* This last one is just for the tty layer internals and shouldn't be used elsewhere */
extern void tty_ldisc_enable(struct tty_struct *tty);


/* n_tty.c */
extern struct tty_ldisc_ops tty_ldisc_N_TTY;
extern void n_tty_inherit_ops(struct tty_ldisc_ops *ops);

/* tty_audit.c */
#ifdef CONFIG_AUDIT
extern void tty_audit_add_data(struct tty_struct *tty, unsigned char *data,
                   size_t size);
extern void tty_audit_exit(void);
extern void tty_audit_fork(struct signal_struct *sig);
extern void tty_audit_tiocsti(struct tty_struct *tty, char ch);
extern void tty_audit_push(struct tty_struct *tty);
extern int tty_audit_push_task(struct task_struct *tsk,
                   kuid_t loginuid, u32 sessionid);
#else
static inline void tty_audit_add_data(struct tty_struct *tty,
                      unsigned char *data, size_t size)
{
}
static inline void tty_audit_tiocsti(struct tty_struct *tty, char ch)
{
}
static inline void tty_audit_exit(void)
{
}
static inline void tty_audit_fork(struct signal_struct *sig)
{
}
static inline void tty_audit_push(struct tty_struct *tty)
{
}
static inline int tty_audit_push_task(struct task_struct *tsk,
                      kuid_t loginuid, u32 sessionid)
{
    return 0;
}
#endif

/* tty_io.c */
extern int __init tty_init(void);

/* tty_ioctl.c */
extern int n_tty_ioctl_helper(struct tty_struct *tty, struct file *file,
               unsigned int cmd, unsigned long arg);
extern long n_tty_compat_ioctl_helper(struct tty_struct *tty, struct file *file,
               unsigned int cmd, unsigned long arg);

/* serial.c */

extern void serial_console_init(void);

/* pcxx.c */

extern int pcxe_open(struct tty_struct *tty, struct file *filp);

/* vt.c */

extern int vt_ioctl(struct tty_struct *tty,
            unsigned int cmd, unsigned long arg);

extern long vt_compat_ioctl(struct tty_struct *tty,
             unsigned int cmd, unsigned long arg);

/* tty_mutex.c */
/* functions for preparation of BKL removal */
extern void __lockfunc tty_lock(struct tty_struct *tty);
extern void __lockfunc tty_unlock(struct tty_struct *tty);
extern void __lockfunc tty_lock_pair(struct tty_struct *tty,
                struct tty_struct *tty2);
extern void __lockfunc tty_unlock_pair(struct tty_struct *tty,
                struct tty_struct *tty2);

/*
 * this shall be called only from where BTM is held (like close)
 *
 * We need this to ensure nobody waits for us to finish while we are waiting.
 * Without this we were encountering system stalls.
 *
 * This should be indeed removed with BTM removal later.
 *
 * Locking: BTM required. Nobody is allowed to hold port->mutex.
 */
static inline void tty_wait_until_sent_from_close(struct tty_struct *tty,
        long timeout)
{
    tty_unlock(tty); /* tty->ops->close holds the BTM, drop it while waiting */
    tty_wait_until_sent(tty, timeout);
    tty_lock(tty);
}

/*
 * wait_event_interruptible_tty -- wait for a condition with the tty lock held
 *
 * The condition we are waiting for might take a long time to
 * become true, or might depend on another thread taking the
 * BTM. In either case, we need to drop the BTM to guarantee
 * forward progress. This is a leftover from the conversion
 * from the BKL and should eventually get removed as the BTM
 * falls out of use.
 *
 * Do not use in new code.
 */
#define wait_event_interruptible_tty(tty, wq, condition)        \
({                                  \
    int __ret = 0;                          \
    if (!(condition)) {                     \
        __wait_event_interruptible_tty(tty, wq, condition, __ret);  \
    }                               \
    __ret;                              \
})

#define __wait_event_interruptible_tty(tty, wq, condition, ret)     \
do {                                    \
    DEFINE_WAIT(__wait);                        \
                                    \
    for (;;) {                          \
        prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE);  \
        if (condition)                      \
            break;                      \
        if (!signal_pending(current)) {             \
            tty_unlock(tty);                    \
            schedule();                 \
            tty_lock(tty);                  \
            continue;                   \
        }                           \
        ret = -ERESTARTSYS;                 \
        break;                          \
    }                               \
    finish_wait(&wq, &__wait);                  \
} while (0)


#endif