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[unix-history] / sys / kern / tty_pty.c

/*
* Copyright (c) 1982, 1986, 1989 The Regents of the University of California.
* All rights reserved.
*
* 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.
* 3. All advertising materials mentioning features or use of this software
*    must display the following acknowledgement:
*      This product includes software developed by the University of
*      California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
*    may be used to endorse or promote products derived from this software
*    without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
*
*      from: @(#)tty_pty.c     7.21 (Berkeley) 5/30/91
*      $Id$
*/

/*
* Pseudo-teletype Driver
* (Actually two drivers, requiring two entries in 'cdevsw')
*/
#include "pty.h"

#if NPTY > 0
#include "param.h"
#include "systm.h"
#include "ioctl.h"
#include "tty.h"
#include "conf.h"
#include "file.h"
#include "proc.h"
#include "uio.h"
#include "kernel.h"
#include "vnode.h"

#if NPTY == 1
#undef NPTY
#define NPTY    32              /* crude XXX */
#endif

#define BUFSIZ 100              /* Chunk size iomoved to/from user */

/*
* pts == /dev/tty[pqrs]?
* ptc == /dev/pty[pqrs]?
*/
struct  tty pt_tty[NPTY];
struct  pt_ioctl {
       int     pt_flags;
       pid_t   pt_selr, pt_selw;
       u_char  pt_send;
       u_char  pt_ucntl;
} pt_ioctl[NPTY];
int     npty = NPTY;            /* for pstat -t */

#define PF_RCOLL        0x01
#define PF_WCOLL        0x02
#define PF_PKT          0x08            /* packet mode */
#define PF_STOPPED      0x10            /* user told stopped */
#define PF_REMOTE       0x20            /* remote and flow controlled input */
#define PF_NOSTOP       0x40
#define PF_UCNTL        0x80            /* user control mode */

/*ARGSUSED*/
ptsopen(dev, flag, devtype, p)
       dev_t dev;
       struct proc *p;
{
       register struct tty *tp;
       int error;

#ifdef lint
       npty = npty;
#endif
       if (minor(dev) >= NPTY)
               return (ENXIO);
       tp = &pt_tty[minor(dev)];
       if ((tp->t_state & TS_ISOPEN) == 0) {
               tp->t_state |= TS_WOPEN;
               ttychars(tp);           /* Set up default chars */
               tp->t_iflag = TTYDEF_IFLAG;
               tp->t_oflag = TTYDEF_OFLAG;
               tp->t_lflag = TTYDEF_LFLAG;
               tp->t_cflag = TTYDEF_CFLAG;
               tp->t_ispeed = tp->t_ospeed = TTYDEF_SPEED;
               ttsetwater(tp);         /* would be done in xxparam() */
       } else if (tp->t_state&TS_XCLUDE && p->p_ucred->cr_uid != 0)
               return (EBUSY);
       if (tp->t_oproc)                        /* Ctrlr still around. */
               tp->t_state |= TS_CARR_ON;
       while ((tp->t_state & TS_CARR_ON) == 0) {
               tp->t_state |= TS_WOPEN;
               if (flag&FNONBLOCK)
                       break;
               if (error = ttysleep(tp, (caddr_t)&tp->t_raw, TTIPRI | PCATCH,
                   ttopen, 0))
                       return (error);
       }
       error = (*linesw[tp->t_line].l_open)(dev, tp, flag);
       ptcwakeup(tp, FREAD|FWRITE);
       return (error);
}

ptsclose(dev, flag, mode, p)
       dev_t dev;
       int flag, mode;
       struct proc *p;
{
       register struct tty *tp;

       tp = &pt_tty[minor(dev)];
       (*linesw[tp->t_line].l_close)(tp, flag);
       ttyclose(tp);
       ptcwakeup(tp, FREAD|FWRITE);
       return(0);
}

ptsread(dev, uio, flag)
       dev_t dev;
       struct uio *uio;
{
       struct proc *p = curproc;
       register struct tty *tp = &pt_tty[minor(dev)];
       register struct pt_ioctl *pti = &pt_ioctl[minor(dev)];
       int error = 0;

again:
       if (pti->pt_flags & PF_REMOTE) {
               while (isbackground(p, tp)) {
                       if ((p->p_sigignore & sigmask(SIGTTIN)) ||
                           (p->p_sigmask & sigmask(SIGTTIN)) ||
                           p->p_pgrp->pg_jobc == 0 ||
                           p->p_flag&SPPWAIT)
                               return (EIO);
                       pgsignal(p->p_pgrp, SIGTTIN, 1);
                       if (error = ttysleep(tp, (caddr_t)&lbolt, 
                           TTIPRI | PCATCH, ttybg, 0))
                               return (error);
               }
               if (RB_LEN(&tp->t_can) == 0) {
                       if (flag & IO_NDELAY)
                               return (EWOULDBLOCK);
                       if (error = ttysleep(tp, (caddr_t)&tp->t_can,
                           TTIPRI | PCATCH, ttyin, 0))
                               return (error);
                       goto again;
               }
               while (RB_LEN(&tp->t_can) > 1 && uio->uio_resid > 0)
                       if (ureadc(getc(&tp->t_can), uio) < 0) {
                               error = EFAULT;
                               break;
                       }
               if (RB_LEN(&tp->t_can) == 1)
                       (void) getc(&tp->t_can);
               if (RB_LEN(&tp->t_can))
                       return (error);
       } else
               if (tp->t_oproc)
                       error = (*linesw[tp->t_line].l_read)(tp, uio, flag);
       ptcwakeup(tp, FWRITE);
       return (error);
}

/*
* Write to pseudo-tty.
* Wakeups of controlling tty will happen
* indirectly, when tty driver calls ptsstart.
*/
ptswrite(dev, uio, flag)
       dev_t dev;
       struct uio *uio;
{
       register struct tty *tp;

       tp = &pt_tty[minor(dev)];
       if (tp->t_oproc == 0)
               return (EIO);
       return ((*linesw[tp->t_line].l_write)(tp, uio, flag));
}

/*
* Start output on pseudo-tty.
* Wake up process selecting or sleeping for input from controlling tty.
*/
ptsstart(tp)
       struct tty *tp;
{
       register struct pt_ioctl *pti = &pt_ioctl[minor(tp->t_dev)];

       if (tp->t_state & TS_TTSTOP)
               return;
       if (pti->pt_flags & PF_STOPPED) {
               pti->pt_flags &= ~PF_STOPPED;
               pti->pt_send = TIOCPKT_START;
       }
       ptcwakeup(tp, FREAD);
}

ptcwakeup(tp, flag)
       struct tty *tp;
{
       struct pt_ioctl *pti = &pt_ioctl[minor(tp->t_dev)];

       if (flag & FREAD) {
               if (pti->pt_selr) {
                       selwakeup(pti->pt_selr, pti->pt_flags & PF_RCOLL);
                       pti->pt_selr = 0;
                       pti->pt_flags &= ~PF_RCOLL;
               }
               wakeup((caddr_t)&tp->t_out.rb_tl);
       }
       if (flag & FWRITE) {
               if (pti->pt_selw) {
                       selwakeup(pti->pt_selw, pti->pt_flags & PF_WCOLL);
                       pti->pt_selw = 0;
                       pti->pt_flags &= ~PF_WCOLL;
               }
               wakeup((caddr_t)&tp->t_raw.rb_hd);
       }
}

/*ARGSUSED*/
#ifdef __STDC__
ptcopen(dev_t dev, int flag, int devtype, struct proc *p)
#else
ptcopen(dev, flag, devtype, p)
       dev_t dev;
       int flag, devtype;
       struct proc *p;
#endif
{
       register struct tty *tp;
       struct pt_ioctl *pti;

       if (minor(dev) >= NPTY)
               return (ENXIO);
       tp = &pt_tty[minor(dev)];
       if (tp->t_oproc)
               return (EIO);
       tp->t_oproc = ptsstart;
       (void)(*linesw[tp->t_line].l_modem)(tp, 1);
       tp->t_lflag &= ~EXTPROC;
       pti = &pt_ioctl[minor(dev)];
       pti->pt_flags = 0;
       pti->pt_send = 0;
       pti->pt_ucntl = 0;
       return (0);
}

extern struct tty *constty;     /* -hv- 06.Oct.92*/
ptcclose(dev)
       dev_t dev;
{
       register struct tty *tp;

       tp = &pt_tty[minor(dev)];
       (void)(*linesw[tp->t_line].l_modem)(tp, 0);
       tp->t_state &= ~TS_CARR_ON;
       tp->t_oproc = 0;                /* mark closed */
       tp->t_session = 0;

/* XXX -hv- 6.Oct.92 this prevents the "hanging console bug" with X11 */
       if (constty==tp)
               constty = 0;

       return (0);
}

ptcread(dev, uio, flag)
       dev_t dev;
       struct uio *uio;
{
       register struct tty *tp = &pt_tty[minor(dev)];
       struct pt_ioctl *pti = &pt_ioctl[minor(dev)];
       char buf[BUFSIZ];
       int error = 0, cc;

       /*
        * We want to block until the slave
        * is open, and there's something to read;
        * but if we lost the slave or we're NBIO,
        * then return the appropriate error instead.
        */
       for (;;) {
               if (tp->t_state&TS_ISOPEN) {
                       if (pti->pt_flags&PF_PKT && pti->pt_send) {
                               error = ureadc((int)pti->pt_send, uio);
                               if (error)
                                       return (error);
                               if (pti->pt_send & TIOCPKT_IOCTL) {
                                       cc = MIN(uio->uio_resid,
                                               sizeof(tp->t_termios));
                                       uiomove(&tp->t_termios, cc, uio);
                               }
                               pti->pt_send = 0;
                               return (0);
                       }
                       if (pti->pt_flags&PF_UCNTL && pti->pt_ucntl) {
                               error = ureadc((int)pti->pt_ucntl, uio);
                               if (error)
                                       return (error);
                               pti->pt_ucntl = 0;
                               return (0);
                       }
                       if (RB_LEN(&tp->t_out) && (tp->t_state&TS_TTSTOP) == 0)
                               break;
               }
               if ((tp->t_state&TS_CARR_ON) == 0)
                       return (0);     /* EOF */
               if (flag & IO_NDELAY)
                       return (EWOULDBLOCK);
               if (error = tsleep((caddr_t)&tp->t_out.rb_tl, TTIPRI | PCATCH,
                   ttyin, 0))
                       return (error);
       }
       if (pti->pt_flags & (PF_PKT|PF_UCNTL))
               error = ureadc(0, uio);
       while (uio->uio_resid > 0 && error == 0) {
#ifdef was
               cc = q_to_b(&tp->t_outq, buf, MIN(uio->uio_resid, BUFSIZ));
#else
               cc = min(MIN(uio->uio_resid, BUFSIZ), RB_CONTIGGET(&tp->t_out));
               if (cc) {
                       bcopy(tp->t_out.rb_hd, buf, cc);
                       tp->t_out.rb_hd =
                               RB_ROLLOVER(&tp->t_out, tp->t_out.rb_hd+cc);
               }
#endif
               if (cc <= 0)
                       break;
               error = uiomove(buf, cc, uio);
       }
       if (RB_LEN(&tp->t_out) <= tp->t_lowat) {
               if (tp->t_state&TS_ASLEEP) {
                       tp->t_state &= ~TS_ASLEEP;
                       wakeup((caddr_t)&tp->t_out);
               }
               if (tp->t_wsel) {
                       selwakeup(tp->t_wsel, tp->t_state & TS_WCOLL);
                       tp->t_wsel = 0;
                       tp->t_state &= ~TS_WCOLL;
               }
       }
       return (error);
}

ptsstop(tp, flush)
       register struct tty *tp;
       int flush;
{
       struct pt_ioctl *pti = &pt_ioctl[minor(tp->t_dev)];
       int flag;

       /* note: FLUSHREAD and FLUSHWRITE already ok */
       if (flush == 0) {
               flush = TIOCPKT_STOP;
               pti->pt_flags |= PF_STOPPED;
       } else
               pti->pt_flags &= ~PF_STOPPED;
       pti->pt_send |= flush;
       /* change of perspective */
       flag = 0;
       if (flush & FREAD)
               flag |= FWRITE;
       if (flush & FWRITE)
               flag |= FREAD;
       ptcwakeup(tp, flag);
}

ptcselect(dev, rw, p)
       dev_t dev;
       int rw;
       struct proc *p;
{
       register struct tty *tp = &pt_tty[minor(dev)];
       struct pt_ioctl *pti = &pt_ioctl[minor(dev)];
       struct proc *prev;
       int s;

       if ((tp->t_state&TS_CARR_ON) == 0)
               return (1);
       switch (rw) {

       case FREAD:
               /*
                * Need to block timeouts (ttrstart).
                */
               s = spltty();
               if ((tp->t_state&TS_ISOPEN) &&
                    RB_LEN(&tp->t_out) && (tp->t_state&TS_TTSTOP) == 0) {
                       splx(s);
                       return (1);
               }
               splx(s);
               /* FALLTHROUGH */

       case 0:                                 /* exceptional */
               if ((tp->t_state&TS_ISOPEN) &&
                   (pti->pt_flags&PF_PKT && pti->pt_send ||
                    pti->pt_flags&PF_UCNTL && pti->pt_ucntl))
                       return (1);
               if (pti->pt_selr && (prev = pfind(pti->pt_selr)) && prev->p_wchan == (caddr_t)&selwait)
                       pti->pt_flags |= PF_RCOLL;
               else
                       pti->pt_selr = p->p_pid;
               break;


       case FWRITE:
               if (tp->t_state&TS_ISOPEN) {
                       if (pti->pt_flags & PF_REMOTE) {
                           if (RB_LEN(&tp->t_can) == 0)
                               return (1);
                       } else {
                           if (RB_LEN(&tp->t_raw) + RB_LEN(&tp->t_can) < TTYHOG-2)
                                   return (1);
                           if (RB_LEN(&tp->t_can) == 0 && (tp->t_iflag&ICANON))
                                   return (1);
                       }
               }
               if (pti->pt_selw && (prev = pfind(pti->pt_selw)) && prev->p_wchan == (caddr_t)&selwait)
                       pti->pt_flags |= PF_WCOLL;
               else
                       pti->pt_selw = p->p_pid;
               break;

       }
       return (0);
}

ptcwrite(dev, uio, flag)
       dev_t dev;
       register struct uio *uio;
{
       register struct tty *tp = &pt_tty[minor(dev)];
       register u_char *cp;
       register int cc = 0;
       u_char locbuf[BUFSIZ];
       int cnt = 0;
       struct pt_ioctl *pti = &pt_ioctl[minor(dev)];
       int error = 0;

again:
       if ((tp->t_state&TS_ISOPEN) == 0)
               goto block;
       if (pti->pt_flags & PF_REMOTE) {
               if (RB_LEN(&tp->t_can))
                       goto block;
               while (uio->uio_resid > 0 && RB_LEN(&tp->t_can) < TTYHOG - 1) {
                       if (cc == 0) {
                               cc = min(uio->uio_resid, BUFSIZ);
                               cc = min(cc, RB_CONTIGPUT(&tp->t_can));
                               cp = locbuf;
                               error = uiomove((caddr_t)cp, cc, uio);
                               if (error)
                                       return (error);
                               /* check again for safety */
                               if ((tp->t_state&TS_ISOPEN) == 0)
                                       return (EIO);
                       }
#ifdef was
                       if (cc)
                               (void) b_to_q((char *)cp, cc, &tp->t_canq);
#else
                       if (cc) {
                               bcopy(cp, tp->t_can.rb_tl, cc);
                               tp->t_can.rb_tl =
                                 RB_ROLLOVER(&tp->t_can, tp->t_can.rb_tl+cc);
                       }
#endif
                       cc = 0;
               }
               (void) putc(0, &tp->t_can);
               ttwakeup(tp);
               wakeup((caddr_t)&tp->t_can);
               return (0);
       }
       while (uio->uio_resid > 0) {
               if (cc == 0) {
                       cc = min(uio->uio_resid, BUFSIZ);
                       cp = locbuf;
                       error = uiomove((caddr_t)cp, cc, uio);
                       if (error)
                               return (error);
                       /* check again for safety */
                       if ((tp->t_state&TS_ISOPEN) == 0)
                               return (EIO);
               }
               while (cc > 0) {
                       if ((RB_LEN(&tp->t_raw) + RB_LEN(&tp->t_can)) >= TTYHOG - 2 &&
                          (RB_LEN(&tp->t_can) > 0 || !(tp->t_iflag&ICANON))) {
                               wakeup((caddr_t)&tp->t_raw);
                               goto block;
                       }
                       (*linesw[tp->t_line].l_rint)(*cp++, tp);
                       cnt++;
                       cc--;
               }
               cc = 0;
       }
       return (0);
block:
       /*
        * Come here to wait for slave to open, for space
        * in outq, or space in rawq.
        */
       if ((tp->t_state&TS_CARR_ON) == 0)
               return (EIO);
       if (flag & IO_NDELAY) {
               /* adjust for data copied in but not written */
               uio->uio_resid += cc;
               if (cnt == 0)
                       return (EWOULDBLOCK);
               return (0);
       }
       if (error = tsleep((caddr_t)&tp->t_raw.rb_hd, TTOPRI | PCATCH,
           ttyout, 0)) {
               /* adjust for data copied in but not written */
               uio->uio_resid += cc;
               return (error);
       }
       goto again;
}

/*ARGSUSED*/
ptyioctl(dev, cmd, data, flag)
       caddr_t data;
       dev_t dev;
{
       register struct tty *tp = &pt_tty[minor(dev)];
       register struct pt_ioctl *pti = &pt_ioctl[minor(dev)];
       register u_char *cc = tp->t_cc;
       int stop, error;
       extern ttyinput();

       /*
        * IF CONTROLLER STTY THEN MUST FLUSH TO PREVENT A HANG.
        * ttywflush(tp) will hang if there are characters in the outq.
        */
       if (cmd == TIOCEXT) {
               /*
                * When the EXTPROC bit is being toggled, we need
                * to send an TIOCPKT_IOCTL if the packet driver
                * is turned on.
                */
               if (*(int *)data) {
                       if (pti->pt_flags & PF_PKT) {
                               pti->pt_send |= TIOCPKT_IOCTL;
                               ptcwakeup(tp, FREAD);
                       }
                       tp->t_lflag |= EXTPROC;
               } else {
                       if ((tp->t_state & EXTPROC) &&
                           (pti->pt_flags & PF_PKT)) {
                               pti->pt_send |= TIOCPKT_IOCTL;
                               ptcwakeup(tp, FREAD);
                       }
                       tp->t_lflag &= ~EXTPROC;
               }
               return(0);
       } else
       if (cdevsw[major(dev)].d_open == ptcopen)
               switch (cmd) {

               case TIOCGPGRP:
                       /*
                        * We aviod calling ttioctl on the controller since,
                        * in that case, tp must be the controlling terminal.
                        */
                       *(int *)data = tp->t_pgrp ? tp->t_pgrp->pg_id : 0;
                       return (0);

               case TIOCPKT:
                       if (*(int *)data) {
                               if (pti->pt_flags & PF_UCNTL)
                                       return (EINVAL);
                               pti->pt_flags |= PF_PKT;
                       } else
                               pti->pt_flags &= ~PF_PKT;
                       return (0);

               case TIOCUCNTL:
                       if (*(int *)data) {
                               if (pti->pt_flags & PF_PKT)
                                       return (EINVAL);
                               pti->pt_flags |= PF_UCNTL;
                       } else
                               pti->pt_flags &= ~PF_UCNTL;
                       return (0);

               case TIOCREMOTE:
                       if (*(int *)data)
                               pti->pt_flags |= PF_REMOTE;
                       else
                               pti->pt_flags &= ~PF_REMOTE;
                       ttyflush(tp, FREAD|FWRITE);
                       return (0);

#ifdef COMPAT_43
       /* wkt */
               case TIOCSETP:          
               case TIOCSETN:
#endif
               case TIOCSETD:
               case TIOCSETA:
               case TIOCSETAW:
               case TIOCSETAF:
                       while (getc(&tp->t_out) >= 0)
                               ;
                       break;

               case TIOCSIG:
                       if (*(unsigned int *)data >= NSIG)
                               return(EINVAL);
                       if ((tp->t_lflag&NOFLSH) == 0)
                               ttyflush(tp, FREAD|FWRITE);
                       pgsignal(tp->t_pgrp, *(unsigned int *)data, 1);
                       if ((*(unsigned int *)data == SIGINFO) &&
                           ((tp->t_lflag&NOKERNINFO) == 0))
                               ttyinfo(tp);
                       return(0);
               }
       error = (*linesw[tp->t_line].l_ioctl)(tp, cmd, data, flag);
       if (error >= 0)
           return (error);
       error = ttioctl(tp, cmd, data, flag);
       /*
        * Since we use the tty queues internally,
        * pty's can't be switched to disciplines which overwrite
        * the queues.  We can't tell anything about the discipline
        * from here...
        */
       if (linesw[tp->t_line].l_rint != ttyinput) {
               (*linesw[tp->t_line].l_close)(tp, flag);
               tp->t_line = TTYDISC;
               (void)(*linesw[tp->t_line].l_open)(dev, tp, flag);
               error = ENOTTY;
       }
       if (error < 0) {
               if (pti->pt_flags & PF_UCNTL &&
                   (cmd & ~0xff) == UIOCCMD(0)) {
                       if (cmd & 0xff) {
                               pti->pt_ucntl = (u_char)cmd;
                               ptcwakeup(tp, FREAD);
                       }
                       return (0);
               }
               error = ENOTTY;
       }
       /*
        * If external processing and packet mode send ioctl packet.
        */
       if ((tp->t_lflag&EXTPROC) && (pti->pt_flags & PF_PKT)) {
               switch(cmd) {
               case TIOCSETA:
               case TIOCSETAW:
               case TIOCSETAF:
#ifdef  COMPAT_43
       /* wkt */
               case TIOCSETP:
               case TIOCSETN:
               case TIOCSETC:
               case TIOCSLTC:
               case TIOCLBIS:
               case TIOCLBIC:
               case TIOCLSET:
#endif
                       pti->pt_send |= TIOCPKT_IOCTL;
               default:
                       break;
               }
       }
       stop = (tp->t_iflag & IXON) && CCEQ(cc[VSTOP], CTRL('s')) 
               && CCEQ(cc[VSTART], CTRL('q'));
       if (pti->pt_flags & PF_NOSTOP) {
               if (stop) {
                       pti->pt_send &= ~TIOCPKT_NOSTOP;
                       pti->pt_send |= TIOCPKT_DOSTOP;
                       pti->pt_flags &= ~PF_NOSTOP;
                       ptcwakeup(tp, FREAD);
               }
       } else {
               if (!stop) {
                       pti->pt_send &= ~TIOCPKT_DOSTOP;
                       pti->pt_send |= TIOCPKT_NOSTOP;
                       pti->pt_flags |= PF_NOSTOP;
                       ptcwakeup(tp, FREAD);
               }
       }
       return (error);
}
#endif