tn3270/telnet/Source/sys_bsd.c

/*
 * Copyright (c) 1988 Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that the above copyright notice and this paragraph are
 * duplicated in all such forms and that any documentation,
 * advertising materials, and other materials related to such
 * distribution and use acknowledge that the software was developed
 * by the University of California, Berkeley.  The name of the
 * University may not be used to endorse or promote products derived
 * from this software without specific prior written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

#ifndef lint
static char sccsid[] = "@(#)sys_bsd.c   1.16 (Berkeley) 11/29/88";
#endif /* not lint */

/*
 * The following routines try to encapsulate what is system dependent
 * (at least between 4.x and dos) which is used in telnet.c.
 */

#if     defined(unix)

#include <fcntl.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/socket.h>
#include <signal.h>
#include <errno.h>

#include "ring.h"

#include "fdset.h"

#include "defines.h"
#include "externs.h"
#include "types.h"

int
        tout,                   /* Output file descriptor */
        tin,                    /* Input file descriptor */
        net;

static struct   tchars otc = { 0 }, ntc = { 0 };
static struct   ltchars oltc = { 0 }, nltc = { 0 };
static struct   sgttyb ottyb = { 0 }, nttyb = { 0 };

static fd_set ibits, obits, xbits;


init_sys()
{
    tout = fileno(stdout);
    tin = fileno(stdin);
    FD_ZERO(&ibits);
    FD_ZERO(&obits);
    FD_ZERO(&xbits);

    errno = 0;
}


TerminalWrite(buf, n)
char    *buf;
int     n;
{
    return write(tout, buf, n);
}

TerminalRead(buf, n)
char    *buf;
int     n;
{
    return read(tin, buf, n);
}

/*
 *
 */

int
TerminalAutoFlush()
{
#if     defined(LNOFLSH)
    int flush;

    ioctl(0, TIOCLGET, (char *)&flush);
    return !(flush&LNOFLSH);    /* if LNOFLSH, no autoflush */
#else   /* LNOFLSH */
    return 1;
#endif  /* LNOFLSH */
}

/*
 * TerminalSpecialChars()
 *
 * Look at an input character to see if it is a special character
 * and decide what to do.
 *
 * Output:
 *
 *      0       Don't add this character.
 *      1       Do add this character
 */

int
TerminalSpecialChars(c)
int     c;
{
    void xmitAO(), xmitEL(), xmitEC(), intp(), sendbrk();

    if (c == ntc.t_intrc) {
        intp();
        return 0;
    } else if (c == ntc.t_quitc) {
        sendbrk();
        return 0;
    } else if (c == nltc.t_flushc) {
        xmitAO();               /* Transmit Abort Output */
        return 0;
    } else if (!MODE_LOCAL_CHARS(globalmode)) {
        if (c == nttyb.sg_kill) {
            xmitEL();
            return 0;
        } else if (c == nttyb.sg_erase) {
            xmitEC();           /* Transmit Erase Character */
            return 0;
        }
    }
    return 1;
}


/*
 * Flush output to the terminal
 */

void
TerminalFlushOutput()
{
    (void) ioctl(fileno(stdout), TIOCFLUSH, (char *) 0);
}

void
TerminalSaveState()
{
    ioctl(0, TIOCGETP, (char *)&ottyb);
    ioctl(0, TIOCGETC, (char *)&otc);
    ioctl(0, TIOCGLTC, (char *)&oltc);

    ntc = otc;
    nltc = oltc;
    nttyb = ottyb;

    termEofChar = ntc.t_eofc;
    termEraseChar = nttyb.sg_erase;
    termFlushChar = nltc.t_flushc;
    termIntChar = ntc.t_intrc;
    termKillChar = nttyb.sg_kill;
    termQuitChar = ntc.t_quitc;
}

void
TerminalRestoreState()
{
}

/*
 * TerminalNewMode - set up terminal to a specific mode.
 */


void
TerminalNewMode(f)
register int f;
{
    static int prevmode = 0;
    struct tchars *tc;
    struct tchars tc3;
    struct ltchars *ltc;
    struct sgttyb sb;
    int onoff;
    int old;
    struct      tchars notc2;
    struct      ltchars noltc2;
    static struct       tchars notc =   { -1, -1, -1, -1, -1, -1 };
    static struct       ltchars noltc = { -1, -1, -1, -1, -1, -1 };

    globalmode = f;
    if (prevmode == f)
        return;
    old = prevmode;
    prevmode = f;
    sb = nttyb;

    switch (f) {

    case 0:
        onoff = 0;
        tc = &otc;
        ltc = &oltc;
        break;

    case 1:             /* remote character processing, remote echo */
    case 2:             /* remote character processing, local echo */
    case 6:             /* 3270 mode - like 1, but with xon/xoff local */
                    /* (might be nice to have "6" in telnet also...) */
            sb.sg_flags |= CBREAK;
            if ((f == 1) || (f == 6)) {
                sb.sg_flags &= ~(ECHO|CRMOD);
            } else {
                sb.sg_flags |= ECHO|CRMOD;
            }
            sb.sg_erase = sb.sg_kill = -1;
            if (f == 6) {
                tc = &tc3;
                tc3 = notc;
                    /* get XON, XOFF characters */
                tc3.t_startc = otc.t_startc;
                tc3.t_stopc = otc.t_stopc;
            } else {
                /*
                 * If user hasn't specified one way or the other,
                 * then default to not trapping signals.
                 */
                if (!donelclchars) {
                    localchars = 0;
                }
                if (localchars) {
                    notc2 = notc;
                    notc2.t_intrc = ntc.t_intrc;
                    notc2.t_quitc = ntc.t_quitc;
                    tc = &notc2;
                } else {
                    tc = &notc;
                }
            }
            ltc = &noltc;
            onoff = 1;
            break;
    case 3:             /* local character processing, remote echo */
    case 4:             /* local character processing, local echo */
    case 5:             /* local character processing, no echo */
            sb.sg_flags &= ~CBREAK;
            sb.sg_flags |= CRMOD;
            if (f == 4)
                sb.sg_flags |= ECHO;
            else
                sb.sg_flags &= ~ECHO;
            notc2 = ntc;
            tc = &notc2;
            noltc2 = oltc;
            ltc = &noltc2;
            /*
             * If user hasn't specified one way or the other,
             * then default to trapping signals.
             */
            if (!donelclchars) {
                localchars = 1;
            }
            if (localchars) {
                notc2.t_brkc = nltc.t_flushc;
                noltc2.t_flushc = -1;
            } else {
                notc2.t_intrc = notc2.t_quitc = -1;
            }
            noltc2.t_suspc = escape;
            noltc2.t_dsuspc = -1;
            onoff = 1;
            break;

    default:
            return;
    }
    ioctl(tin, TIOCSLTC, (char *)ltc);
    ioctl(tin, TIOCSETC, (char *)tc);
    ioctl(tin, TIOCSETP, (char *)&sb);
#if     (!defined(TN3270)) || ((!defined(NOT43)) || defined(PUTCHAR))
    ioctl(tin, FIONBIO, (char *)&onoff);
    ioctl(tout, FIONBIO, (char *)&onoff);
#endif  /* (!defined(TN3270)) || ((!defined(NOT43)) || defined(PUTCHAR)) */
#if     defined(TN3270)
    if (noasynchtty == 0) {
        ioctl(tin, FIOASYNC, (char *)&onoff);
    }
#endif  /* defined(TN3270) */

    if (MODE_LINE(f)) {
        void doescape();

        (void) signal(SIGTSTP, (int (*)())doescape);
    } else if (MODE_LINE(old)) {
        (void) signal(SIGTSTP, SIG_DFL);
        sigsetmask(sigblock(0) & ~(1<<(SIGTSTP-1)));
    }
}


int
NetClose(fd)
int     fd;
{
    return close(fd);
}


void
NetNonblockingIO(fd, onoff)
int
        fd,
        onoff;
{
    ioctl(fd, FIONBIO, (char *)&onoff);
}

#if     defined(TN3270)
void
NetSigIO(fd, onoff)
int
        fd,
        onoff;
{
    ioctl(fd, FIOASYNC, (char *)&onoff);        /* hear about input */
}

void
NetSetPgrp(fd)
int fd;
{
    int myPid;

    myPid = getpid();
    fcntl(fd, F_SETOWN, myPid);
}
#endif  /*defined(TN3270)*/
\f
/*
 * Various signal handling routines.
 */

static void
deadpeer()
{
        setcommandmode();
        longjmp(peerdied, -1);
}

static void
intr()
{
    if (localchars) {
        intp();
        return;
    }
    setcommandmode();
    longjmp(toplevel, -1);
}

static void
intr2()
{
    if (localchars) {
        sendbrk();
        return;
    }
}

static void
doescape()
{
    command(0);
}
\f
void
sys_telnet_init()
{
    (void) signal(SIGINT, (int (*)())intr);
    (void) signal(SIGQUIT, (int (*)())intr2);
    (void) signal(SIGPIPE, (int (*)())deadpeer);

    setconnmode();

    NetNonblockingIO(net, 1);

#if     defined(TN3270)
    if (noasynchnet == 0) {                     /* DBX can't handle! */
        NetSigIO(net, 1);
        NetSetPgrp(net);
    }
#endif  /* defined(TN3270) */

#if     defined(SO_OOBINLINE)
    if (SetSockOpt(net, SOL_SOCKET, SO_OOBINLINE, 1) == -1) {
        perror("SetSockOpt");
    }
#endif  /* defined(SO_OOBINLINE) */
}

/*
 * Process rings -
 *
 *      This routine tries to fill up/empty our various rings.
 *
 *      The parameter specifies whether this is a poll operation,
 *      or a block-until-something-happens operation.
 *
 *      The return value is 1 if something happened, 0 if not.
 */

int
process_rings(netin, netout, netex, ttyin, ttyout, poll)
int poll;               /* If 0, then block until something to do */
{
    register int c;
                /* One wants to be a bit careful about setting returnValue
                 * to one, since a one implies we did some useful work,
                 * and therefore probably won't be called to block next
                 * time (TN3270 mode only).
                 */
    int returnValue = 0;
    static struct timeval TimeValue = { 0 };

    if (netout) {
        FD_SET(net, &obits);
    }
    if (ttyout) {
        FD_SET(tout, &obits);
    }
#if     defined(TN3270)
    if (ttyin) {
        FD_SET(tin, &ibits);
    }
#else   /* defined(TN3270) */
    if (ttyin) {
        FD_SET(tin, &ibits);
    }
#endif  /* defined(TN3270) */
#if     defined(TN3270)
    if (netin) {
        FD_SET(net, &ibits);
    }
#   else /* !defined(TN3270) */
    if (netin) {
        FD_SET(net, &ibits);
    }
#   endif /* !defined(TN3270) */
    if (netex) {
        FD_SET(net, &xbits);
    }
    if ((c = select(16, &ibits, &obits, &xbits,
                        (poll == 0)? (struct timeval *)0 : &TimeValue)) < 0) {
        if (c == -1) {
                    /*
                     * we can get EINTR if we are in line mode,
                     * and the user does an escape (TSTP), or
                     * some other signal generator.
                     */
            if (errno == EINTR) {
                return 0;
            }
#           if defined(TN3270)
                    /*
                     * we can get EBADF if we were in transparent
                     * mode, and the transcom process died.
                    */
            if (errno == EBADF) {
                        /*
                         * zero the bits (even though kernel does it)
                         * to make sure we are selecting on the right
                         * ones.
                        */
                FD_ZERO(&ibits);
                FD_ZERO(&obits);
                FD_ZERO(&xbits);
                return 0;
            }
#           endif /* defined(TN3270) */
                    /* I don't like this, does it ever happen? */
            printf("sleep(5) from telnet, after select\r\n");
            sleep(5);
        }
        return 0;
    }

    /*
     * Any urgent data?
     */
    if (FD_ISSET(net, &xbits)) {
        FD_CLR(net, &xbits);
        SYNCHing = 1;
        ttyflush(1);    /* flush already enqueued data */
    }

    /*
     * Something to read from the network...
     */
    if (FD_ISSET(net, &ibits)) {
        int canread;

        FD_CLR(net, &ibits);
        canread = ring_empty_consecutive(&netiring);
#if     !defined(SO_OOBINLINE)
            /*
             * In 4.2 (and some early 4.3) systems, the
             * OOB indication and data handling in the kernel
             * is such that if two separate TCP Urgent requests
             * come in, one byte of TCP data will be overlaid.
             * This is fatal for Telnet, but we try to live
             * with it.
             *
             * In addition, in 4.2 (and...), a special protocol
             * is needed to pick up the TCP Urgent data in
             * the correct sequence.
             *
             * What we do is:  if we think we are in urgent
             * mode, we look to see if we are "at the mark".
             * If we are, we do an OOB receive.  If we run
             * this twice, we will do the OOB receive twice,
             * but the second will fail, since the second
             * time we were "at the mark", but there wasn't
             * any data there (the kernel doesn't reset
             * "at the mark" until we do a normal read).
             * Once we've read the OOB data, we go ahead
             * and do normal reads.
             *
             * There is also another problem, which is that
             * since the OOB byte we read doesn't put us
             * out of OOB state, and since that byte is most
             * likely the TELNET DM (data mark), we would
             * stay in the TELNET SYNCH (SYNCHing) state.
             * So, clocks to the rescue.  If we've "just"
             * received a DM, then we test for the
             * presence of OOB data when the receive OOB
             * fails (and AFTER we did the normal mode read
             * to clear "at the mark").
             */
        if (SYNCHing) {
            int atmark;

            ioctl(net, SIOCATMARK, (char *)&atmark);
            if (atmark) {
                c = recv(net, netiring.supply, canread, MSG_OOB);
                if ((c == -1) && (errno == EINVAL)) {
                    c = recv(net, netiring.supply, canread, 0);
                    if (clocks.didnetreceive < clocks.gotDM) {
                        SYNCHing = stilloob(net);
                    }
                }
            } else {
                c = recv(net, netiring.supply, canread, 0);
            }
        } else {
            c = recv(net, netiring.supply, canread, 0);
        }
        settimer(didnetreceive);
#else   /* !defined(SO_OOBINLINE) */
        c = recv(net, netiring.supply, canread, 0);
#endif  /* !defined(SO_OOBINLINE) */
        if (c < 0 && errno == EWOULDBLOCK) {
            c = 0;
        } else if (c <= 0) {
            return -1;
        }
        if (netdata) {
            Dump('<', netiring.supply, c);
        }
        if (c)
            ring_supplied(&netiring, c);
        returnValue = 1;
    }

    /*
     * Something to read from the tty...
     */
    if (FD_ISSET(tin, &ibits)) {
        FD_CLR(tin, &ibits);
        c = TerminalRead(ttyiring.supply, ring_empty_consecutive(&ttyiring));
        if (c < 0 && errno == EWOULDBLOCK) {
            c = 0;
        } else {
            /* EOF detection for line mode!!!! */
            if ((c == 0) && MODE_LOCAL_CHARS(globalmode) && isatty(tin)) {
                        /* must be an EOF... */
                *ttyiring.supply = termEofChar;
                c = 1;
            }
            if (c <= 0) {
                return -1;
            }
            ring_supplied(&ttyiring, c);
        }
        returnValue = 1;                /* did something useful */
    }

    if (FD_ISSET(net, &obits)) {
        FD_CLR(net, &obits);
        returnValue |= netflush();
    }
    if (FD_ISSET(tout, &obits)) {
        FD_CLR(tout, &obits);
        returnValue |= ttyflush(SYNCHing|flushout);
    }

    return returnValue;
}
#endif  /* defined(unix) */