path: root/include/linux/tty.h

#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_bufhead	buf;		/* Locked internally */
	struct tty_struct	*tty;		/* Back pointer */
	struct tty_struct	*itty;		/* internal back ptr */
	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 long		iflags;		/* TTYP_ internal flags */
#define TTYP_FLUSHING			1  /* Flushing to ldisc in progress */
#define TTYP_FLUSHPENDING		2  /* Queued buffer flush pending */
	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 atomic_write_lock;
	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;
	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

	unsigned char closing:1;
	unsigned short minimum_to_wake;
	unsigned char *write_buf;
	int write_cnt;
	/* 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_HUPPING 		21	/* ->hangup() in progress */

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

extern void tty_write_flush(struct tty_struct *);

extern