/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2008 Ed Schouten <ed@FreeBSD.org>
 * All rights reserved.
 *
 * Portions of this software were developed under sponsorship from Snow
 * B.V., the Netherlands.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifndef _SYS_TTY_H_
#define _SYS_TTY_H_

#include <sys/param.h>
#include <sys/queue.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/condvar.h>
#include <sys/selinfo.h>
#include <sys/_termios.h>
#include <sys/ttycom.h>
#include <sys/ttyqueue.h>

struct cdev;
struct file;
struct pgrp;
struct session;
struct ucred;

struct ttydevsw;

/*
 * Per-TTY structure, containing buffers, etc.
 *
 * List of locks
 * (t)  locked by t_mtx
 * (l)  locked by tty_list_sx
 * (c)  const until freeing
 */
struct tty {
        struct mtx      *t_mtx;         /* TTY lock. */
        struct mtx      t_mtxobj;       /* Per-TTY lock (when not borrowing). */
        TAILQ_ENTRY(tty) t_list;        /* (l) TTY list entry. */
        int             t_drainwait;    /* (t) TIOCDRAIN timeout seconds. */
        unsigned int    t_flags;        /* (t) Terminal option flags. */
/* Keep flags in sync with db_show_tty and pstat(8). */
#define TF_NOPREFIX     0x00001 /* Don't prepend "tty" to device name. */
#define TF_INITLOCK     0x00002 /* Create init/lock state devices. */
#define TF_CALLOUT      0x00004 /* Create "cua" devices. */
#define TF_OPENED_IN    0x00008 /* "tty" node is in use. */
#define TF_OPENED_OUT   0x00010 /* "cua" node is in use. */
#define TF_OPENED_CONS  0x00020 /* Device in use as console. */
#define TF_OPENED       (TF_OPENED_IN|TF_OPENED_OUT|TF_OPENED_CONS)
#define TF_GONE         0x00040 /* Device node is gone. */
#define TF_OPENCLOSE    0x00080 /* Device is in open()/close(). */
#define TF_ASYNC        0x00100 /* Asynchronous I/O enabled. */
#define TF_LITERAL      0x00200 /* Accept the next character literally. */
#define TF_HIWAT_IN     0x00400 /* We've reached the input watermark. */
#define TF_HIWAT_OUT    0x00800 /* We've reached the output watermark. */
#define TF_HIWAT        (TF_HIWAT_IN|TF_HIWAT_OUT)
#define TF_STOPPED      0x01000 /* Output flow control - stopped. */
#define TF_EXCLUDE      0x02000 /* Exclusive access. */
#define TF_BYPASS       0x04000 /* Optimized input path. */
#define TF_ZOMBIE       0x08000 /* Modem disconnect received. */
#define TF_HOOK         0x10000 /* TTY has hook attached. */
#define TF_BUSY_IN      0x20000 /* Process busy in read() -- not supported. */
#define TF_BUSY_OUT     0x40000 /* Process busy in write(). */
#define TF_BUSY         (TF_BUSY_IN|TF_BUSY_OUT)
        unsigned int    t_revokecnt;    /* (t) revoke() count. */

        /* Buffering mechanisms. */
        struct ttyinq   t_inq;          /* (t) Input queue. */
        size_t          t_inlow;        /* (t) Input low watermark. */
        struct ttyoutq  t_outq;         /* (t) Output queue. */
        size_t          t_outlow;       /* (t) Output low watermark. */

        /* Sleeping mechanisms. */
        struct cv       t_inwait;       /* (t) Input wait queue. */
        struct cv       t_outwait;      /* (t) Output wait queue. */
        struct cv       t_outserwait;   /* (t) Serial output wait queue. */
        struct cv       t_bgwait;       /* (t) Background wait queue. */
        struct cv       t_dcdwait;      /* (t) Carrier Detect wait queue. */

        /* Polling mechanisms. */
        struct selinfo  t_inpoll;       /* (t) Input poll queue. */
        struct selinfo  t_outpoll;      /* (t) Output poll queue. */
        struct sigio    *t_sigio;       /* (t) Asynchronous I/O. */

        struct termios  t_termios;      /* (t) I/O processing flags. */
        struct winsize  t_winsize;      /* (t) Window size. */
        unsigned int    t_column;       /* (t) Current cursor position. */
        unsigned int    t_writepos;     /* (t) Where input was interrupted. */
        int             t_compatflags;  /* (t) COMPAT_43TTY flags. */

        /* Init/lock-state devices. */
        struct termios  t_termios_init_in;      /* tty%s.init. */
        struct termios  t_termios_lock_in;      /* tty%s.lock. */
        struct termios  t_termios_init_out;     /* cua%s.init. */
        struct termios  t_termios_lock_out;     /* cua%s.lock. */

        struct ttydevsw *t_devsw;       /* (c) Driver hooks. */
        struct ttyhook  *t_hook;        /* (t) Capture/inject hook. */

        /* Process signal delivery. */
        struct pgrp     *t_pgrp;        /* (t) Foreground process group. */
        struct session  *t_session;     /* (t) Associated session. */
        unsigned int    t_sessioncnt;   /* (t) Backpointing sessions. */

        void            *t_devswsoftc;  /* (c) Soft config, for drivers. */
        void            *t_hooksoftc;   /* (t) Soft config, for hooks. */
        struct cdev     *t_dev;         /* (c) Primary character device. */

        size_t          t_prbufsz;      /* (t) SIGINFO buffer size. */
        char            t_prbuf[];      /* (t) SIGINFO buffer. */
};

/*
 * Userland version of struct tty, for sysctl kern.ttys
 */
struct xtty {
        size_t  xt_size;        /* Structure size. */
        size_t  xt_insize;      /* Input queue size. */
        size_t  xt_incc;        /* Canonicalized characters. */
        size_t  xt_inlc;        /* Input line characters. */
        size_t  xt_inlow;       /* Input low watermark. */
        size_t  xt_outsize;     /* Output queue size. */
        size_t  xt_outcc;       /* Output queue usage. */
        size_t  xt_outlow;      /* Output low watermark. */
        unsigned int xt_column; /* Current column position. */
        pid_t   xt_pgid;        /* Foreground process group. */
        pid_t   xt_sid;         /* Session. */
        unsigned int xt_flags;  /* Terminal option flags. */
        uint32_t xt_dev;        /* Userland device. XXXKIB truncated */
};

#ifdef _KERNEL

/* Used to distinguish between normal, callout, lock and init devices. */
#define TTYUNIT_INIT            0x1
#define TTYUNIT_LOCK            0x2
#define TTYUNIT_CALLOUT         0x4

/* Allocation and deallocation. */
struct tty *tty_alloc(struct ttydevsw *tsw, void *softc);
struct tty *tty_alloc_mutex(struct ttydevsw *tsw, void *softc, struct mtx *mtx);
void    tty_rel_pgrp(struct tty *tp, struct pgrp *pgrp);
void    tty_rel_sess(struct tty *tp, struct session *sess);
void    tty_rel_gone(struct tty *tp);

#define tty_lock(tp)            mtx_lock((tp)->t_mtx)
#define tty_unlock(tp)          mtx_unlock((tp)->t_mtx)
#define tty_lock_owned(tp)      mtx_owned((tp)->t_mtx)
#define tty_assert_locked(tp)   mtx_assert((tp)->t_mtx, MA_OWNED)
#define tty_getlock(tp)         ((tp)->t_mtx)

/* XXX Should migrate users to tty_assert_locked! */
#define tty_lock_assert(tp, ma) mtx_assert((tp)->t_mtx, (ma))

/* Device node creation. */
int     tty_makedevf(struct tty *tp, struct ucred *cred, int flags,
    const char *fmt, ...) __printflike(4, 5);
#define TTYMK_CLONING           0x1
#define tty_makedev(tp, cred, fmt, ...) \
        (void )tty_makedevf((tp), (cred), 0, (fmt), ## __VA_ARGS__)
#define tty_makealias(tp,fmt,...) \
        make_dev_alias((tp)->t_dev, fmt, ## __VA_ARGS__)

/* Signalling processes. */
void    tty_signal_sessleader(struct tty *tp, int signal);
void    tty_signal_pgrp(struct tty *tp, int signal);
/* Waking up readers/writers. */
int     tty_wait(struct tty *tp, struct cv *cv);
int     tty_wait_background(struct tty *tp, struct thread *td, int sig);
int     tty_timedwait(struct tty *tp, struct cv *cv, int timo);
void    tty_wakeup(struct tty *tp, int flags);

/* System messages. */
int     tty_checkoutq(struct tty *tp);
int     tty_putchar(struct tty *tp, char c);
int     tty_putstrn(struct tty *tp, const char *p, size_t n);

int     tty_ioctl(struct tty *tp, u_long cmd, void *data, int fflag,
    struct thread *td);
int     tty_ioctl_compat(struct tty *tp, u_long cmd, caddr_t data,
    int fflag, struct thread *td);
void    tty_set_winsize(struct tty *tp, const struct winsize *wsz);
void    tty_init_console(struct tty *tp, speed_t speed);
void    tty_flush(struct tty *tp, int flags);
void    tty_hiwat_in_block(struct tty *tp);
void    tty_hiwat_in_unblock(struct tty *tp);
dev_t   tty_udev(struct tty *tp);
#define tty_opened(tp)          ((tp)->t_flags & TF_OPENED)
#define tty_gone(tp)            ((tp)->t_flags & TF_GONE)
#define tty_softc(tp)           ((tp)->t_devswsoftc)
#define tty_devname(tp)         devtoname((tp)->t_dev)

/* Status line printing. */
void    tty_info(struct tty *tp);

/* /dev/console selection. */
void    ttyconsdev_select(const char *name);

/* Pseudo-terminal hooks. */
int     pts_alloc(int fflags, struct thread *td, struct file *fp);
int     pts_alloc_external(int fd, struct thread *td, struct file *fp,
    struct cdev *dev, const char *name);

/* Drivers and line disciplines also need to call these. */
#include <sys/ttydisc.h>
#include <sys/ttydevsw.h>
#include <sys/ttyhook.h>
#endif /* _KERNEL */

#endif /* !_SYS_TTY_H_ */