/*      $OpenBSD: sys_bsd.c,v 1.36 2023/02/08 08:22:44 tb Exp $ */
/*      $NetBSD: sys_bsd.c,v 1.11 1996/02/28 21:04:10 thorpej Exp $     */

/*
 * Copyright (c) 1988, 1990, 1993
 *      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. 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.
 */

#include "telnet_locl.h"

#include <sys/ioctl.h>
#include <sys/socket.h>
#include <arpa/telnet.h>
#include <errno.h>
#include <poll.h>
#include <string.h>
#include <unistd.h>

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

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

#define TELNET_FD_TOUT  0
#define TELNET_FD_TIN   1
#define TELNET_FD_NET   2
#define TELNET_FD_NUM   3

struct  termios old_tc = { 0 };

void
init_sys(void)
{
    tout = fileno(stdout);
    tin = fileno(stdin);

    errno = 0;
}


/*
 * 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(int c)
{
    if (c == termIntChar) {
        intp();
        return 0;
    } else if (c == termQuitChar) {
#ifdef  KLUDGELINEMODE
        if (kludgelinemode)
            sendbrk();
        else
#endif
            sendabort();
        return 0;
    } else if (c == termEofChar) {
        if (my_want_state_is_will(TELOPT_LINEMODE)) {
            sendeof();
            return 0;
        }
        return 1;
    } else if (c == termSuspChar) {
        sendsusp();
        return(0);
    } else if (c == termFlushChar) {
        xmitAO();               /* Transmit Abort Output */
        return 0;
    } else if (!MODE_LOCAL_CHARS(globalmode)) {
        if (c == termKillChar) {
            xmitEL();
            return 0;
        } else if (c == termEraseChar) {
            xmitEC();           /* Transmit Erase Character */
            return 0;
        }
    }
    return 1;
}

void
TerminalSaveState(void)
{
    tcgetattr(0, &old_tc);

    new_tc = old_tc;
}

cc_t *
tcval(int func)
{
    switch(func) {
    case SLC_IP:        return(&termIntChar);
    case SLC_ABORT:     return(&termQuitChar);
    case SLC_EOF:       return(&termEofChar);
    case SLC_EC:        return(&termEraseChar);
    case SLC_EL:        return(&termKillChar);
    case SLC_XON:       return(&termStartChar);
    case SLC_XOFF:      return(&termStopChar);
    case SLC_FORW1:     return(&termForw1Char);
    case SLC_FORW2:     return(&termForw2Char);
    case SLC_SUSP:      return(&termSuspChar);
    case SLC_AO:        return(&termFlushChar);
    case SLC_EW:        return(&termWerasChar);
    case SLC_RP:        return(&termRprntChar);
    case SLC_LNEXT:     return(&termLiteralNextChar);
    case SLC_AYT:       return(&termAytChar);
    case SLC_SYNCH:
    case SLC_BRK:
    case SLC_EOR:
    default:
        return(NULL);
    }
}

void
TerminalDefaultChars(void)
{
    memcpy(new_tc.c_cc, old_tc.c_cc, sizeof(old_tc.c_cc));
}

/*
 * TerminalNewMode - set up terminal to a specific mode.
 *      MODE_ECHO: do local terminal echo
 *      MODE_FLOW: do local flow control
 *      MODE_TRAPSIG: do local mapping to TELNET IAC sequences
 *      MODE_EDIT: do local line editing
 *
 *      Command mode:
 *              MODE_ECHO|MODE_EDIT|MODE_FLOW|MODE_TRAPSIG
 *              local echo
 *              local editing
 *              local xon/xoff
 *              local signal mapping
 *
 *      Linemode:
 *              local/no editing
 *      Both Linemode and Single Character mode:
 *              local/remote echo
 *              local/no xon/xoff
 *              local/no signal mapping
 */

static void susp(int);
static void ayt(int);

void
TerminalNewMode(int f)
{
    static int prevmode = 0;
    struct termios tmp_tc;
    int onoff;
    int old;
    cc_t esc;

    globalmode = f&~MODE_FORCE;
    if (prevmode == f)
        return;

    /*
     * Write any outstanding data before switching modes
     * ttyflush() returns 0 only when there is no more data
     * left to write out, it returns -1 if it couldn't do
     * anything at all, otherwise it returns 1 + the number
     * of characters left to write.
     */
    old = ttyflush(SYNCHing|flushout);
    if (old < 0 || old > 1) {
        tcgetattr(tin, &tmp_tc);
        do {
            /*
             * Wait for data to drain, then flush again.
             */
            if (isatty(tin))
                tcsetattr(tin, TCSADRAIN, &tmp_tc);
            old = ttyflush(SYNCHing|flushout);
        } while (old < 0 || old > 1);
    }

    old = prevmode;
    prevmode = f&~MODE_FORCE;
    tmp_tc = new_tc;

    if (f&MODE_ECHO) {
        tmp_tc.c_lflag |= ECHO;
        tmp_tc.c_oflag |= ONLCR;
        if (crlf)
                tmp_tc.c_iflag |= ICRNL;
    } else {
        tmp_tc.c_lflag &= ~ECHO;
        tmp_tc.c_oflag &= ~ONLCR;
    }

    if ((f&MODE_FLOW) == 0) {
        tmp_tc.c_iflag &= ~(IXOFF|IXON);        /* Leave the IXANY bit alone */
    } else {
        if (restartany < 0) {
                tmp_tc.c_iflag |= IXOFF|IXON;   /* Leave the IXANY bit alone */
        } else if (restartany > 0) {
                tmp_tc.c_iflag |= IXOFF|IXON|IXANY;
        } else {
                tmp_tc.c_iflag |= IXOFF|IXON;
                tmp_tc.c_iflag &= ~IXANY;
        }
    }

    if ((f&MODE_TRAPSIG) == 0) {
        tmp_tc.c_lflag &= ~ISIG;
        localchars = 0;
    } else {
        tmp_tc.c_lflag |= ISIG;
        localchars = 1;
    }

    if (f&MODE_EDIT) {
        tmp_tc.c_lflag |= ICANON;
    } else {
        tmp_tc.c_lflag &= ~ICANON;
        tmp_tc.c_iflag &= ~ICRNL;
        tmp_tc.c_cc[VMIN] = 1;
        tmp_tc.c_cc[VTIME] = 0;
    }

    if ((f&(MODE_EDIT|MODE_TRAPSIG)) == 0) {
        tmp_tc.c_lflag &= ~IEXTEN;
    }

    if (f&MODE_SOFT_TAB) {
# ifdef OXTABS
        tmp_tc.c_oflag |= OXTABS;
# endif
# ifdef TABDLY
        tmp_tc.c_oflag &= ~TABDLY;
        tmp_tc.c_oflag |= TAB3;
# endif
    } else {
# ifdef OXTABS
        tmp_tc.c_oflag &= ~OXTABS;
# endif
# ifdef TABDLY
        tmp_tc.c_oflag &= ~TABDLY;
# endif
    }

    if (f&MODE_LIT_ECHO) {
# ifdef ECHOCTL
        tmp_tc.c_lflag &= ~ECHOCTL;
# endif
    } else {
# ifdef ECHOCTL
        tmp_tc.c_lflag |= ECHOCTL;
# endif
    }

    if (f == -1) {
        onoff = 0;
    } else {
        if (f & MODE_INBIN)
                tmp_tc.c_iflag &= ~ISTRIP;
        else
                tmp_tc.c_iflag |= ISTRIP;
        if ((f & MODE_OUTBIN) || (f & MODE_OUT8)) {
                tmp_tc.c_cflag &= ~(CSIZE|PARENB);
                tmp_tc.c_cflag |= CS8;
                if(f & MODE_OUTBIN)
                        tmp_tc.c_oflag &= ~OPOST;
                else
                        tmp_tc.c_oflag |= OPOST;

        } else {
                tmp_tc.c_cflag &= ~(CSIZE|PARENB);
                tmp_tc.c_cflag |= old_tc.c_cflag & (CSIZE|PARENB);
                tmp_tc.c_oflag |= OPOST;
        }
        onoff = 1;
    }

    if (f != -1) {
        (void) signal(SIGTSTP, susp);
        (void) signal(SIGINFO, ayt);
#if     defined(NOKERNINFO)
        tmp_tc.c_lflag |= NOKERNINFO;
#endif
        /*
         * We don't want to process ^Y here.  It's just another
         * character that we'll pass on to the back end.  It has
         * to process it because it will be processed when the
         * user attempts to read it, not when we send it.
         */
# ifdef VDSUSP
        tmp_tc.c_cc[VDSUSP] = (cc_t)(_POSIX_VDISABLE);
# endif
        /*
         * If the VEOL character is already set, then use VEOL2,
         * otherwise use VEOL.
         */
        esc = (rlogin != _POSIX_VDISABLE) ? rlogin : escape;
        if ((tmp_tc.c_cc[VEOL] != esc)
# ifdef VEOL2
            && (tmp_tc.c_cc[VEOL2] != esc)
# endif
            ) {
                if (tmp_tc.c_cc[VEOL] == (cc_t)(_POSIX_VDISABLE))
                    tmp_tc.c_cc[VEOL] = esc;
# ifdef VEOL2
                else if (tmp_tc.c_cc[VEOL2] == (cc_t)(_POSIX_VDISABLE))
                    tmp_tc.c_cc[VEOL2] = esc;
# endif
        }
    } else {
        sigset_t mask;
        (void) signal(SIGINFO, ayt_status);
        (void) signal(SIGTSTP, SIG_DFL);
        sigemptyset(&mask);
        sigaddset(&mask, SIGTSTP);
        sigprocmask(SIG_UNBLOCK, &mask, NULL);
        tmp_tc = old_tc;
    }
    if (isatty(tin) && tcsetattr(tin, TCSADRAIN, &tmp_tc) == -1)
        tcsetattr(tin, TCSANOW, &tmp_tc);

    ioctl(tin, FIONBIO, &onoff);
    ioctl(tout, FIONBIO, &onoff);
}

void
TerminalSpeeds(long *ispeed, long *ospeed)
{
    long in, out;

    out = cfgetospeed(&old_tc);
    in = cfgetispeed(&old_tc);
    if (in == 0)
        in = out;

    *ispeed = in;
    *ospeed = out;
}

int
TerminalWindowSize(long *rows, long *cols)
{
    struct winsize ws;

    if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) == 0) {
        *rows = ws.ws_row;
        *cols = ws.ws_col;
        return 1;
    }
    return 0;
}

/*
 * Various signal handling routines.
 */

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

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

void
intr2(int sig)
{
    if (localchars) {
#ifdef  KLUDGELINEMODE
        if (kludgelinemode)
            sendbrk();
        else
#endif
            sendabort();
        return;
    }
}

void
susp(int sig)
{
    if ((rlogin != _POSIX_VDISABLE) && rlogin_susp())
        return;
    if (localchars)
        sendsusp();
}

void
sendwin(int sig)
{
    if (connected) {
        sendnaws();
    }
}

void
ayt(int sig)
{
    if (connected)
        sendayt();
    else
        ayt_status(sig);
}


void
sys_telnet_init(void)
{
    int one = 1;

    (void) signal(SIGINT, intr);
    (void) signal(SIGQUIT, intr2);
    (void) signal(SIGPIPE, deadpeer);
    (void) signal(SIGWINCH, sendwin);
    (void) signal(SIGTSTP, susp);
    (void) signal(SIGINFO, ayt);

    setconnmode(0);

    /*
     * Mark the socket as non-blocking and receive urgent data inline.
     * (The latter is required for correct telnet operation when a
     * second urgent is sent before telnet can process the first.)
     */
    ioctl(net, FIONBIO, &one);
    if (setsockopt(net, SOL_SOCKET, SO_OOBINLINE, &one, sizeof(one)) == -1) {
        perror("setsockopt");
    }
}

/*
 * 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(int netin, int netout, int netex, int ttyin, int ttyout,
    int dopoll)         /* If 0, then block until something to do */
{
    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;
    struct pollfd pfd[TELNET_FD_NUM];

    if (ttyout) {
        pfd[TELNET_FD_TOUT].fd = tout;
        pfd[TELNET_FD_TOUT].events = POLLOUT;
    } else {
        pfd[TELNET_FD_TOUT].fd = -1;
    }
    if (ttyin) {
        pfd[TELNET_FD_TIN].fd = tin;
        pfd[TELNET_FD_TIN].events = POLLIN;
    } else {
        pfd[TELNET_FD_TIN].fd = -1;
    }
    if (netout || netin || netex) {
        pfd[TELNET_FD_NET].fd = net;
        pfd[TELNET_FD_NET].events = 0;
        if (netout)
            pfd[TELNET_FD_NET].events |= POLLOUT;
        if (netin)
            pfd[TELNET_FD_NET].events |= POLLIN;
        if (netex)
            pfd[TELNET_FD_NET].events |= POLLRDBAND;
    } else {
        pfd[TELNET_FD_NET].fd = -1;
    }

    if ((c = poll(pfd, TELNET_FD_NUM, dopoll ? 0 : INFTIM)) == -1) {
        return 0;
    }

    /*
     * Any urgent data?
     */
    if (pfd[TELNET_FD_NET].revents & POLLRDBAND) {
        SYNCHing = 1;
        (void) ttyflush(1);     /* flush already enqueued data */
    }

    /*
     * Something to read from the network...
     */
    if (pfd[TELNET_FD_NET].revents & (POLLIN|POLLHUP)) {
        int canread;

        canread = ring_empty_consecutive(&netiring);
        c = recv(net, netiring.supply, canread, 0);
        if (c == -1 && 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 (pfd[TELNET_FD_TIN].revents & (POLLIN|POLLHUP)) {
        c = read(tin, ttyiring.supply, ring_empty_consecutive(&ttyiring));
        if (c == -1 && errno == EIO)
            c = 0;
        if (c == -1 && 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;
            }
            if (termdata) {
                Dump('<', ttyiring.supply, c);
            }
            ring_supplied(&ttyiring, c);
        }
        returnValue = 1;                /* did something useful */
    }

    if (pfd[TELNET_FD_NET].revents & POLLOUT) {
        returnValue |= netflush();
    }
    if (pfd[TELNET_FD_TOUT].revents & POLLOUT) {
        returnValue |= (ttyflush(SYNCHing|flushout) > 0);
    }

    return returnValue;
}