/*
 * Copyright (c) 1989, 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.
 */

#if 0
#ifndef lint
static const char sccsid[] = "@(#)telnetd.c     8.4 (Berkeley) 5/30/95";
#endif
#endif
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");

#include "telnetd.h"
#include "pathnames.h"

#include <sys/mman.h>
#include <err.h>
#include <libutil.h>
#include <paths.h>
#include <termcap.h>

#include <arpa/inet.h>

#ifdef  AUTHENTICATION
#include <libtelnet/auth.h>
#endif
#ifdef  ENCRYPTION
#include <libtelnet/encrypt.h>
#endif
#include <libtelnet/misc.h>

char    remote_hostname[MAXHOSTNAMELEN];
size_t  utmp_len = sizeof(remote_hostname) - 1;
int     registerd_host_only = 0;


/*
 * I/O data buffers,
 * pointers, and counters.
 */
char    ptyibuf[BUFSIZ], *ptyip = ptyibuf;
char    ptyibuf2[BUFSIZ];

int readstream(int, char *, int);
void doit(struct sockaddr *);
int terminaltypeok(char *);

int     hostinfo = 1;                   /* do we print login banner? */

static int debug = 0;
int keepalive = 1;
const char *altlogin;

void doit(struct sockaddr *);
int terminaltypeok(char *);
void startslave(char *, int, char *);
extern void usage(void);
static void _gettermname(void);

/*
 * The string to pass to getopt().  We do it this way so
 * that only the actual options that we support will be
 * passed off to getopt().
 */
char valid_opts[] = {
        'd', ':', 'h', 'k', 'n', 'p', ':', 'S', ':', 'u', ':', 'U',
        '4', '6',
#ifdef  AUTHENTICATION
        'a', ':', 'X', ':',
#endif
#ifdef BFTPDAEMON
        'B',
#endif
#ifdef DIAGNOSTICS
        'D', ':',
#endif
#ifdef  ENCRYPTION
        'e', ':',
#endif
#ifdef  LINEMODE
        'l',
#endif
        '\0'
};

int family = AF_INET;

#ifndef MAXHOSTNAMELEN
#define MAXHOSTNAMELEN 256
#endif  /* MAXHOSTNAMELEN */

char *hostname;
char host_name[MAXHOSTNAMELEN];

extern void telnet(int, int, char *);

int level;
char user_name[256];

int
main(int argc, char *argv[])
{
        u_long ultmp;
        struct sockaddr_storage from;
        int on = 1, fromlen;
        int ch;
#if     defined(IPPROTO_IP) && defined(IP_TOS)
        int tos = -1;
#endif
        char *ep;

        pfrontp = pbackp = ptyobuf;
        netip = netibuf;
        nfrontp = nbackp = netobuf;
#ifdef  ENCRYPTION
        nclearto = 0;
#endif  /* ENCRYPTION */

        /*
         * This initialization causes linemode to default to a configuration
         * that works on all telnet clients, including the FreeBSD client.
         * This is not quite the same as the telnet client issuing a "mode
         * character" command, but has most of the same benefits, and is
         * preferable since some clients (like usofts) don't have the
         * mode character command anyway and linemode breaks things.
         * The most notable symptom of fix is that csh "set filec" operations
         * like <ESC> (filename completion) and ^D (choices) keys now work
         * in telnet sessions and can be used more than once on the same line.
         * CR/LF handling is also corrected in some termio modes.  This 
         * change resolves problem reports bin/771 and bin/1037.
         */

        linemode=1;     /*Default to mode that works on bulk of clients*/

        while ((ch = getopt(argc, argv, valid_opts)) != -1) {
                switch(ch) {

#ifdef  AUTHENTICATION
                case 'a':
                        /*
                         * Check for required authentication level
                         */
                        if (strcmp(optarg, "debug") == 0) {
                                extern int auth_debug_mode;
                                auth_debug_mode = 1;
                        } else if (strcasecmp(optarg, "none") == 0) {
                                auth_level = 0;
                        } else if (strcasecmp(optarg, "other") == 0) {
                                auth_level = AUTH_OTHER;
                        } else if (strcasecmp(optarg, "user") == 0) {
                                auth_level = AUTH_USER;
                        } else if (strcasecmp(optarg, "valid") == 0) {
                                auth_level = AUTH_VALID;
                        } else if (strcasecmp(optarg, "off") == 0) {
                                /*
                                 * This hack turns off authentication
                                 */
                                auth_level = -1;
                        } else {
                                warnx("unknown authorization level for -a");
                        }
                        break;
#endif  /* AUTHENTICATION */

#ifdef BFTPDAEMON
                case 'B':
                        bftpd++;
                        break;
#endif /* BFTPDAEMON */

                case 'd':
                        if (strcmp(optarg, "ebug") == 0) {
                                debug++;
                                break;
                        }
                        usage();
                        /* NOTREACHED */
                        break;

#ifdef DIAGNOSTICS
                case 'D':
                        /*
                         * Check for desired diagnostics capabilities.
                         */
                        if (!strcmp(optarg, "report")) {
                                diagnostic |= TD_REPORT|TD_OPTIONS;
                        } else if (!strcmp(optarg, "exercise")) {
                                diagnostic |= TD_EXERCISE;
                        } else if (!strcmp(optarg, "netdata")) {
                                diagnostic |= TD_NETDATA;
                        } else if (!strcmp(optarg, "ptydata")) {
                                diagnostic |= TD_PTYDATA;
                        } else if (!strcmp(optarg, "options")) {
                                diagnostic |= TD_OPTIONS;
                        } else {
                                usage();
                                /* NOT REACHED */
                        }
                        break;
#endif /* DIAGNOSTICS */

#ifdef  ENCRYPTION
                case 'e':
                        if (strcmp(optarg, "debug") == 0) {
                                extern int encrypt_debug_mode;
                                encrypt_debug_mode = 1;
                                break;
                        }
                        usage();
                        /* NOTREACHED */
                        break;
#endif  /* ENCRYPTION */

                case 'h':
                        hostinfo = 0;
                        break;

#ifdef  LINEMODE
                case 'l':
                        alwayslinemode = 1;
                        break;
#endif  /* LINEMODE */

                case 'k':
#if     defined(LINEMODE) && defined(KLUDGELINEMODE)
                        lmodetype = NO_AUTOKLUDGE;
#else
                        /* ignore -k option if built without kludge linemode */
#endif  /* defined(LINEMODE) && defined(KLUDGELINEMODE) */
                        break;

                case 'n':
                        keepalive = 0;
                        break;

                case 'p':
                        altlogin = optarg;
                        break;

                case 'S':
#ifdef  HAS_GETTOS
                        if ((tos = parsetos(optarg, "tcp")) < 0)
                                warnx("%s%s%s",
                                        "bad TOS argument '", optarg,
                                        "'; will try to use default TOS");
#else
#define MAXTOS  255
                        ultmp = strtoul(optarg, &ep, 0);
                        if (*ep || ep == optarg || ultmp > MAXTOS)
                                warnx("%s%s%s",
                                        "bad TOS argument '", optarg,
                                        "'; will try to use default TOS");
                        else
                                tos = ultmp;
#endif
                        break;

                case 'u':
                        utmp_len = (size_t)atoi(optarg);
                        if (utmp_len >= sizeof(remote_hostname))
                                utmp_len = sizeof(remote_hostname) - 1;
                        break;

                case 'U':
                        registerd_host_only = 1;
                        break;

#ifdef  AUTHENTICATION
                case 'X':
                        /*
                         * Check for invalid authentication types
                         */
                        auth_disable_name(optarg);
                        break;
#endif  /* AUTHENTICATION */

                case '4':
                        family = AF_INET;
                        break;

#ifdef INET6
                case '6':
                        family = AF_INET6;
                        break;
#endif

                default:
                        warnx("%c: unknown option", ch);
                        /* FALLTHROUGH */
                case '?':
                        usage();
                        /* NOTREACHED */
                }
        }

        argc -= optind;
        argv += optind;

        if (debug) {
            int s, ns, foo, error;
            const char *service = "telnet";
            struct addrinfo hints, *res;

            if (argc > 1) {
                usage();
                /* NOT REACHED */
            } else if (argc == 1)
                service = *argv;

            memset(&hints, 0, sizeof(hints));
            hints.ai_flags = AI_PASSIVE;
            hints.ai_family = family;
            hints.ai_socktype = SOCK_STREAM;
            hints.ai_protocol = 0;
            error = getaddrinfo(NULL, service, &hints, &res);

            if (error) {
                errx(1, "tcp/%s: %s\n", service, gai_strerror(error));
                if (error == EAI_SYSTEM)
                    errx(1, "tcp/%s: %s\n", service, strerror(errno));
                usage();
            }

            s = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
            if (s < 0)
                    err(1, "socket");
            (void) setsockopt(s, SOL_SOCKET, SO_REUSEADDR,
                                (char *)&on, sizeof(on));
            if (debug > 1)
                (void) setsockopt(s, SOL_SOCKET, SO_DEBUG,
                                (char *)&on, sizeof(on));
            if (bind(s, res->ai_addr, res->ai_addrlen) < 0)
                err(1, "bind");
            if (listen(s, 1) < 0)
                err(1, "listen");
            foo = res->ai_addrlen;
            ns = accept(s, res->ai_addr, &foo);
            if (ns < 0)
                err(1, "accept");
            (void) setsockopt(ns, SOL_SOCKET, SO_DEBUG,
                                (char *)&on, sizeof(on));
            (void) dup2(ns, 0);
            (void) close(ns);
            (void) close(s);
#ifdef convex
        } else if (argc == 1) {
                ; /* VOID*/             /* Just ignore the host/port name */
#endif
        } else if (argc > 0) {
                usage();
                /* NOT REACHED */
        }

        openlog("telnetd", LOG_PID | LOG_ODELAY, LOG_DAEMON);
        fromlen = sizeof (from);
        if (getpeername(0, (struct sockaddr *)&from, &fromlen) < 0) {
                warn("getpeername");
                _exit(1);
        }
        if (keepalive &&
            setsockopt(0, SOL_SOCKET, SO_KEEPALIVE,
                        (char *)&on, sizeof (on)) < 0) {
                syslog(LOG_WARNING, "setsockopt (SO_KEEPALIVE): %m");
        }

#if     defined(IPPROTO_IP) && defined(IP_TOS)
        if (from.ss_family == AF_INET) {
# if    defined(HAS_GETTOS)
                struct tosent *tp;
                if (tos < 0 && (tp = gettosbyname("telnet", "tcp")))
                        tos = tp->t_tos;
# endif
                if (tos < 0)
                        tos = 020;      /* Low Delay bit */
                if (tos
                   && (setsockopt(0, IPPROTO_IP, IP_TOS,
                                  (char *)&tos, sizeof(tos)) < 0)
                   && (errno != ENOPROTOOPT) )
                        syslog(LOG_WARNING, "setsockopt (IP_TOS): %m");
        }
#endif  /* defined(IPPROTO_IP) && defined(IP_TOS) */
        net = 0;
        doit((struct sockaddr *)&from);
        /* NOTREACHED */
        return(0);
}  /* end of main */

        void
usage()
{
        fprintf(stderr, "usage: telnetd");
#ifdef  AUTHENTICATION
        fprintf(stderr,
            " [-4] [-6] [-a (debug|other|user|valid|off|none)]\n\t");
#endif
#ifdef BFTPDAEMON
        fprintf(stderr, " [-B]");
#endif
        fprintf(stderr, " [-debug]");
#ifdef DIAGNOSTICS
        fprintf(stderr, " [-D (options|report|exercise|netdata|ptydata)]\n\t");
#endif
#ifdef  AUTHENTICATION
        fprintf(stderr, " [-edebug]");
#endif
        fprintf(stderr, " [-h]");
#if     defined(LINEMODE) && defined(KLUDGELINEMODE)
        fprintf(stderr, " [-k]");
#endif
#ifdef LINEMODE
        fprintf(stderr, " [-l]");
#endif
        fprintf(stderr, " [-n]");
        fprintf(stderr, "\n\t");
#ifdef  HAS_GETTOS
        fprintf(stderr, " [-S tos]");
#endif
#ifdef  AUTHENTICATION
        fprintf(stderr, " [-X auth-type]");
#endif
        fprintf(stderr, " [-u utmp_hostname_length] [-U]");
        fprintf(stderr, " [port]\n");
        exit(1);
}

/*
 * getterminaltype
 *
 *      Ask the other end to send along its terminal type and speed.
 * Output is the variable terminaltype filled in.
 */
static unsigned char ttytype_sbbuf[] = {
        IAC, SB, TELOPT_TTYPE, TELQUAL_SEND, IAC, SE
};


#ifndef AUTHENTICATION
#define undef2 __unused
#else
#define undef2
#endif

static int
getterminaltype(char *name undef2)
{
    int retval = -1;

    settimer(baseline);
#ifdef  AUTHENTICATION
    /*
     * Handle the Authentication option before we do anything else.
     */
    if (auth_level >= 0) {
        send_do(TELOPT_AUTHENTICATION, 1);
        while (his_will_wont_is_changing(TELOPT_AUTHENTICATION))
            ttloop();
        if (his_state_is_will(TELOPT_AUTHENTICATION)) {
            retval = auth_wait(name);
        }
    }
#endif

#ifdef  ENCRYPTION
    send_will(TELOPT_ENCRYPT, 1);
#endif  /* ENCRYPTION */
    send_do(TELOPT_TTYPE, 1);
    send_do(TELOPT_TSPEED, 1);
    send_do(TELOPT_XDISPLOC, 1);
    send_do(TELOPT_NEW_ENVIRON, 1);
    send_do(TELOPT_OLD_ENVIRON, 1);
    while (
#ifdef  ENCRYPTION
           his_do_dont_is_changing(TELOPT_ENCRYPT) ||
#endif  /* ENCRYPTION */
           his_will_wont_is_changing(TELOPT_TTYPE) ||
           his_will_wont_is_changing(TELOPT_TSPEED) ||
           his_will_wont_is_changing(TELOPT_XDISPLOC) ||
           his_will_wont_is_changing(TELOPT_NEW_ENVIRON) ||
           his_will_wont_is_changing(TELOPT_OLD_ENVIRON)) {
        ttloop();
    }
#ifdef  ENCRYPTION
    /*
     * Wait for the negotiation of what type of encryption we can
     * send with.  If autoencrypt is not set, this will just return.
     */
    if (his_state_is_will(TELOPT_ENCRYPT)) {
        encrypt_wait();
    }
#endif  /* ENCRYPTION */
    if (his_state_is_will(TELOPT_TSPEED)) {
        static unsigned char sb[] =
                        { IAC, SB, TELOPT_TSPEED, TELQUAL_SEND, IAC, SE };

        output_datalen(sb, sizeof sb);
        DIAG(TD_OPTIONS, printsub('>', sb + 2, sizeof sb - 2););
    }
    if (his_state_is_will(TELOPT_XDISPLOC)) {
        static unsigned char sb[] =
                        { IAC, SB, TELOPT_XDISPLOC, TELQUAL_SEND, IAC, SE };

        output_datalen(sb, sizeof sb);
        DIAG(TD_OPTIONS, printsub('>', sb + 2, sizeof sb - 2););
    }
    if (his_state_is_will(TELOPT_NEW_ENVIRON)) {
        static unsigned char sb[] =
                        { IAC, SB, TELOPT_NEW_ENVIRON, TELQUAL_SEND, IAC, SE };

        output_datalen(sb, sizeof sb);
        DIAG(TD_OPTIONS, printsub('>', sb + 2, sizeof sb - 2););
    }
    else if (his_state_is_will(TELOPT_OLD_ENVIRON)) {
        static unsigned char sb[] =
                        { IAC, SB, TELOPT_OLD_ENVIRON, TELQUAL_SEND, IAC, SE };

        output_datalen(sb, sizeof sb);
        DIAG(TD_OPTIONS, printsub('>', sb + 2, sizeof sb - 2););
    }
    if (his_state_is_will(TELOPT_TTYPE)) {

        output_datalen(ttytype_sbbuf, sizeof ttytype_sbbuf);
        DIAG(TD_OPTIONS, printsub('>', ttytype_sbbuf + 2,
                                        sizeof ttytype_sbbuf - 2););
    }
    if (his_state_is_will(TELOPT_TSPEED)) {
        while (sequenceIs(tspeedsubopt, baseline))
            ttloop();
    }
    if (his_state_is_will(TELOPT_XDISPLOC)) {
        while (sequenceIs(xdisplocsubopt, baseline))
            ttloop();
    }
    if (his_state_is_will(TELOPT_NEW_ENVIRON)) {
        while (sequenceIs(environsubopt, baseline))
            ttloop();
    }
    if (his_state_is_will(TELOPT_OLD_ENVIRON)) {
        while (sequenceIs(oenvironsubopt, baseline))
            ttloop();
    }
    if (his_state_is_will(TELOPT_TTYPE)) {
        char first[256], last[256];

        while (sequenceIs(ttypesubopt, baseline))
            ttloop();

        /*
         * If the other side has already disabled the option, then
         * we have to just go with what we (might) have already gotten.
         */
        if (his_state_is_will(TELOPT_TTYPE) && !terminaltypeok(terminaltype)) {
            (void) strncpy(first, terminaltype, sizeof(first)-1);
            first[sizeof(first)-1] = '\0';
            for(;;) {
                /*
                 * Save the unknown name, and request the next name.
                 */
                (void) strncpy(last, terminaltype, sizeof(last)-1);
                last[sizeof(last)-1] = '\0';
                _gettermname();
                if (terminaltypeok(terminaltype))
                    break;
                if ((strncmp(last, terminaltype, sizeof(last)) == 0) ||
                    his_state_is_wont(TELOPT_TTYPE)) {
                    /*
                     * We've hit the end.  If this is the same as
                     * the first name, just go with it.
                     */
                    if (strncmp(first, terminaltype, sizeof(first)) == 0)
                        break;
                    /*
                     * Get the terminal name one more time, so that
                     * RFC1091 compliant telnets will cycle back to
                     * the start of the list.
                     */
                     _gettermname();
                    if (strncmp(first, terminaltype, sizeof(first)) != 0) {
                        (void) strncpy(terminaltype, first, sizeof(terminaltype)-1);
                        terminaltype[sizeof(terminaltype)-1] = '\0';
                    }
                    break;
                }
            }
        }
    }
    return(retval);
}  /* end of getterminaltype */

static void
_gettermname(void)
{
    /*
     * If the client turned off the option,
     * we can't send another request, so we
     * just return.
     */
    if (his_state_is_wont(TELOPT_TTYPE))
        return;
    settimer(baseline);
    output_datalen(ttytype_sbbuf, sizeof ttytype_sbbuf);
    DIAG(TD_OPTIONS, printsub('>', ttytype_sbbuf + 2,
                                        sizeof ttytype_sbbuf - 2););
    while (sequenceIs(ttypesubopt, baseline))
        ttloop();
}

int
terminaltypeok(char *s)
{
    char buf[1024];

    if (terminaltype == NULL)
        return(1);

    /*
     * tgetent() will return 1 if the type is known, and
     * 0 if it is not known.  If it returns -1, it couldn't
     * open the database.  But if we can't open the database,
     * it won't help to say we failed, because we won't be
     * able to verify anything else.  So, we treat -1 like 1.
     */
    if (tgetent(buf, s) == 0)
        return(0);
    return(1);
}

/*
 * Get a pty, scan input lines.
 */
void
doit(struct sockaddr *who)
{
        int err_; /* XXX */
        int ptynum;

        /*
         * Initialize the slc mapping table.
         */
        get_slc_defaults();

        /*
         * Find an available pty to use.
         */
#ifndef convex
        pty = getpty(&ptynum);
        if (pty < 0)
                fatal(net, "All network ports in use");
#else
        for (;;) {
                char *lp;

                if ((lp = getpty()) == NULL)
                        fatal(net, "Out of ptys");

                if ((pty = open(lp, 2)) >= 0) {
                        strlcpy(line,lp,sizeof(line));
                        line[5] = 't';
                        break;
                }
        }
#endif

        /* get name of connected client */
        if (realhostname_sa(remote_hostname, sizeof(remote_hostname) - 1,
            who, who->sa_len) == HOSTNAME_INVALIDADDR && registerd_host_only)
                fatal(net, "Couldn't resolve your address into a host name.\r\n\
        Please contact your net administrator");
        remote_hostname[sizeof(remote_hostname) - 1] = '\0';

        if (!isdigit(remote_hostname[0]) && strlen(remote_hostname) > utmp_len)
                err_ = getnameinfo(who, who->sa_len, remote_hostname,
                                  sizeof(remote_hostname), NULL, 0,
                                  NI_NUMERICHOST);
                /* XXX: do 'err_' check */

        (void) gethostname(host_name, sizeof(host_name) - 1);
        host_name[sizeof(host_name) - 1] = '\0';
        hostname = host_name;

#ifdef  AUTHENTICATION
#ifdef  ENCRYPTION
/* The above #ifdefs should actually be "or"'ed, not "and"'ed.
 * This is a byproduct of needing "#ifdef" and not "#if defined()"
 * for unifdef. XXX MarkM
 */
        auth_encrypt_init(hostname, remote_hostname, "TELNETD", 1);
#endif
#endif

        init_env();
        /*
         * get terminal type.
         */
        *user_name = 0;
        level = getterminaltype(user_name);
        setenv("TERM", terminaltype ? terminaltype : "network", 1);

        telnet(net, pty, remote_hostname);      /* begin server process */

        /*NOTREACHED*/
}  /* end of doit */

/*
 * Main loop.  Select from pty and network, and
 * hand data to telnet receiver finite state machine.
 */
void
telnet(int f, int p, char *host)
{
        int on = 1;
#define TABBUFSIZ       512
        char    defent[TABBUFSIZ];
        char    defstrs[TABBUFSIZ];
#undef  TABBUFSIZ
        char *HE;
        char *HN;
        char *IM;
        char *IF;
        char *if_buf;
        int if_fd = -1;
        struct stat statbuf;
        int nfd;

        /*
         * Do some tests where it is desireable to wait for a response.
         * Rather than doing them slowly, one at a time, do them all
         * at once.
         */
        if (my_state_is_wont(TELOPT_SGA))
                send_will(TELOPT_SGA, 1);
        /*
         * Is the client side a 4.2 (NOT 4.3) system?  We need to know this
         * because 4.2 clients are unable to deal with TCP urgent data.
         *
         * To find out, we send out a "DO ECHO".  If the remote system
         * answers "WILL ECHO" it is probably a 4.2 client, and we note
         * that fact ("WILL ECHO" ==> that the client will echo what
         * WE, the server, sends it; it does NOT mean that the client will
         * echo the terminal input).
         */
        send_do(TELOPT_ECHO, 1);

#ifdef  LINEMODE
        if (his_state_is_wont(TELOPT_LINEMODE)) {
                /* Query the peer for linemode support by trying to negotiate
                 * the linemode option.
                 */
                linemode = 0;
                editmode = 0;
                send_do(TELOPT_LINEMODE, 1);  /* send do linemode */
        }
#endif  /* LINEMODE */

        /*
         * Send along a couple of other options that we wish to negotiate.
         */
        send_do(TELOPT_NAWS, 1);
        send_will(TELOPT_STATUS, 1);
        flowmode = 1;           /* default flow control state */
        restartany = -1;        /* uninitialized... */
        send_do(TELOPT_LFLOW, 1);

        /*
         * Spin, waiting for a response from the DO ECHO.  However,
         * some REALLY DUMB telnets out there might not respond
         * to the DO ECHO.  So, we spin looking for NAWS, (most dumb
         * telnets so far seem to respond with WONT for a DO that
         * they don't understand...) because by the time we get the
         * response, it will already have processed the DO ECHO.
         * Kludge upon kludge.
         */
        while (his_will_wont_is_changing(TELOPT_NAWS))
                ttloop();

        /*
         * But...
         * The client might have sent a WILL NAWS as part of its
         * startup code; if so, we'll be here before we get the
         * response to the DO ECHO.  We'll make the assumption
         * that any implementation that understands about NAWS
         * is a modern enough implementation that it will respond
         * to our DO ECHO request; hence we'll do another spin
         * waiting for the ECHO option to settle down, which is
         * what we wanted to do in the first place...
         */
        if (his_want_state_is_will(TELOPT_ECHO) &&
            his_state_is_will(TELOPT_NAWS)) {
                while (his_will_wont_is_changing(TELOPT_ECHO))
                        ttloop();
        }
        /*
         * On the off chance that the telnet client is broken and does not
         * respond to the DO ECHO we sent, (after all, we did send the
         * DO NAWS negotiation after the DO ECHO, and we won't get here
         * until a response to the DO NAWS comes back) simulate the
         * receipt of a will echo.  This will also send a WONT ECHO
         * to the client, since we assume that the client failed to
         * respond because it believes that it is already in DO ECHO
         * mode, which we do not want.
         */
        if (his_want_state_is_will(TELOPT_ECHO)) {
                DIAG(TD_OPTIONS, output_data("td: simulating recv\r\n"));
                willoption(TELOPT_ECHO);
        }

        /*
         * Finally, to clean things up, we turn on our echo.  This
         * will break stupid 4.2 telnets out of local terminal echo.
         */

        if (my_state_is_wont(TELOPT_ECHO))
                send_will(TELOPT_ECHO, 1);

#if (!defined(__BEOS__) && !defined(__HAIKU__))
        /*
         * Turn on packet mode
         */
        (void) ioctl(p, TIOCPKT, (char *)&on);
#endif

#if     defined(LINEMODE) && defined(KLUDGELINEMODE)
        /*
         * Continuing line mode support.  If client does not support
         * real linemode, attempt to negotiate kludge linemode by sending
         * the do timing mark sequence.
         */
        if (lmodetype < REAL_LINEMODE)
                send_do(TELOPT_TM, 1);
#endif  /* defined(LINEMODE) && defined(KLUDGELINEMODE) */

        /*
         * Call telrcv() once to pick up anything received during
         * terminal type negotiation, 4.2/4.3 determination, and
         * linemode negotiation.
         */
        telrcv();

        (void) ioctl(f, FIONBIO, (char *)&on);
        (void) ioctl(p, FIONBIO, (char *)&on);

#if     defined(SO_OOBINLINE)
        (void) setsockopt(net, SOL_SOCKET, SO_OOBINLINE,
                                (char *)&on, sizeof on);
#endif  /* defined(SO_OOBINLINE) */

#ifdef  SIGTSTP
        (void) signal(SIGTSTP, SIG_IGN);
#endif
#ifdef  SIGTTOU
        /*
         * Ignoring SIGTTOU keeps the kernel from blocking us
         * in ttioct() in /sys/tty.c.
         */
        (void) signal(SIGTTOU, SIG_IGN);
#endif

        (void) signal(SIGCHLD, cleanup);

#ifdef  TIOCNOTTY
        {
                int t;
                t = open(_PATH_TTY, O_RDWR);
                if (t >= 0) {
                        (void) ioctl(t, TIOCNOTTY, (char *)0);
                        (void) close(t);
                }
        }
#endif

        /*
         * Show banner that getty never gave.
         *
         * We put the banner in the pty input buffer.  This way, it
         * gets carriage return null processing, etc., just like all
         * other pty --> client data.
         */

        if (getent(defent, "default") == 1) {
                char *cp=defstrs;

                HE = Getstr("he", &cp);
                HN = Getstr("hn", &cp);
                IM = Getstr("im", &cp);
                IF = Getstr("if", &cp);
                if (HN && *HN)
                        (void) strlcpy(host_name, HN, sizeof(host_name));
                if (IF) {
                    if_fd = open(IF, O_RDONLY, 000);
                    IM = 0;
                }
                if (IM == 0)
                        IM = strdup("");
        } else {
                IM = strdup(DEFAULT_IM);
                HE = 0;
        }
        edithost(HE, host_name);
        if (hostinfo && *IM)
                putf(IM, ptyibuf2);
        if (if_fd != -1) {
                if (fstat(if_fd, &statbuf) != -1 && statbuf.st_size > 0) {
                        if_buf = (char *) mmap (0, statbuf.st_size,
                            PROT_READ, 0, if_fd, 0);
                        if (if_buf != MAP_FAILED) {
                                putf(if_buf, ptyibuf2);
                                munmap(if_buf, statbuf.st_size);
                        }
                }
                close (if_fd);
        }

        if (pcc)
                (void) strncat(ptyibuf2, ptyip, pcc+1);
        ptyip = ptyibuf2;
        pcc = strlen(ptyip);
#ifdef  LINEMODE
        /*
         * Last check to make sure all our states are correct.
         */
        init_termbuf();
        localstat();
#endif  /* LINEMODE */

        DIAG(TD_REPORT, output_data("td: Entering processing loop\r\n"));

        /*
         * Startup the login process on the slave side of the terminal
         * now.  We delay this until here to insure option negotiation
         * is complete.
         */
        startslave(host, level, user_name);

        nfd = ((f > p) ? f : p) + 1;
        for (;;) {
                fd_set ibits, obits, xbits;
                int c;

                if (ncc < 0 && pcc < 0)
                        break;

                FD_ZERO(&ibits);
                FD_ZERO(&obits);
                FD_ZERO(&xbits);
                /*
                 * Never look for input if there's still
                 * stuff in the corresponding output buffer
                 */
                if (nfrontp - nbackp || pcc > 0) {
                        FD_SET(f, &obits);
                } else {
                        FD_SET(p, &ibits);
                }
                if (pfrontp - pbackp || ncc > 0) {
                        FD_SET(p, &obits);
                } else {
                        FD_SET(f, &ibits);
                }
                if (!SYNCHing) {
                        FD_SET(f, &xbits);
                }
                if ((c = select(nfd, &ibits, &obits, &xbits,
                                                (struct timeval *)0)) < 1) {
                        if (c == -1) {
                                if (errno == EINTR) {
                                        continue;
                                }
                        }
                        sleep(5);
                        continue;
                }

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

                /*
                 * Something to read from the network...
                 */
                if (FD_ISSET(net, &ibits)) {
#if     !defined(SO_OOBINLINE)
                        /*
                         * In 4.2 (and 4.3 beta) 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;

                        (void) ioctl(net, SIOCATMARK, (char *)&atmark);
                        if (atmark) {
                            ncc = recv(net, netibuf, sizeof (netibuf), MSG_OOB);
                            if ((ncc == -1) && (errno == EINVAL)) {
                                ncc = read(net, netibuf, sizeof (netibuf));
                                if (sequenceIs(didnetreceive, gotDM)) {
                                    SYNCHing = stilloob(net);
                                }
                            }
                        } else {
                            ncc = read(net, netibuf, sizeof (netibuf));
                        }
                    } else {
                        ncc = read(net, netibuf, sizeof (netibuf));
                    }
                    settimer(didnetreceive);
#else   /* !defined(SO_OOBINLINE)) */
                    ncc = read(net, netibuf, sizeof (netibuf));
#endif  /* !defined(SO_OOBINLINE)) */
                    if (ncc < 0 && errno == EWOULDBLOCK)
                        ncc = 0;
                    else {
                        if (ncc <= 0) {
                            break;
                        }
                        netip = netibuf;
                    }
                    DIAG((TD_REPORT | TD_NETDATA),
                        output_data("td: netread %d chars\r\n", ncc));
                    DIAG(TD_NETDATA, printdata("nd", netip, ncc));
                }

                /*
                 * Something to read from the pty...
                 */
                if (FD_ISSET(p, &ibits)) {
                        pcc = read(p, ptyibuf, BUFSIZ);
                        /*
                         * On some systems, if we try to read something
                         * off the master side before the slave side is
                         * opened, we get EIO.
                         */
                        if (pcc < 0 && (errno == EWOULDBLOCK ||
#ifdef  EAGAIN
                                        errno == EAGAIN ||
#endif
                                        errno == EIO)) {
                                pcc = 0;
                        } else {
                                if (pcc <= 0)
                                        break;
#ifdef  LINEMODE
                                /*
                                 * If ioctl from pty, pass it through net
                                 */
                                if (ptyibuf[0] & TIOCPKT_IOCTL) {
                                        copy_termbuf(ptyibuf+1, pcc-1);
                                        localstat();
                                        pcc = 1;
                                }
#endif  /* LINEMODE */
#if (!defined(__BEOS__) && !defined(__HAIKU__))
                                if (ptyibuf[0] & TIOCPKT_FLUSHWRITE) {
                                        netclear();     /* clear buffer back */
#ifndef NO_URGENT
                                        /*
                                         * There are client telnets on some
                                         * operating systems get screwed up
                                         * royally if we send them urgent
                                         * mode data.
                                         */
                                        output_data("%c%c", IAC, DM);
                                        neturg = nfrontp-1; /* off by one XXX */
                                        DIAG(TD_OPTIONS,
                                            printoption("td: send IAC", DM));

#endif
                                }
                                if (his_state_is_will(TELOPT_LFLOW) &&
                                    (ptyibuf[0] &
                                     (TIOCPKT_NOSTOP|TIOCPKT_DOSTOP))) {
                                        int newflow =
                                            ptyibuf[0] & TIOCPKT_DOSTOP ? 1 : 0;
                                        if (newflow != flowmode) {
                                                flowmode = newflow;
                                                output_data("%c%c%c%c%c%c",
                                                        IAC, SB, TELOPT_LFLOW,
                                                        flowmode ? LFLOW_ON
                                                                 : LFLOW_OFF,
                                                        IAC, SE);
                                                DIAG(TD_OPTIONS, printsub('>',
                                                    (unsigned char *)nfrontp-4,
                                                    4););
                                        }
                                }
                                pcc--;
#endif  /* !__BEOS__ */
                                //ptyip = ptyibuf+1;
                                ptyip = ptyibuf;
                        }
                }

                while (pcc > 0) {
                        if ((&netobuf[BUFSIZ] - nfrontp) < 2)
                                break;
                        c = *ptyip++ & 0377, pcc--;
                        if (c == IAC)
                                output_data("%c", c);
                        output_data("%c", c);
                        if ((c == '\r') && (my_state_is_wont(TELOPT_BINARY))) {
                                if (pcc > 0 && ((*ptyip & 0377) == '\n')) {
                                        output_data("%c", *ptyip++ & 0377);
                                        pcc--;
                                } else
                                        output_data("%c", '\0');
                        }
                }

                if (FD_ISSET(f, &obits) && (nfrontp - nbackp) > 0)
                        netflush();
                if (ncc > 0)
                        telrcv();
                if (FD_ISSET(p, &obits) && (pfrontp - pbackp) > 0)
                        ptyflush();
        }
        cleanup(0);
}  /* end of telnet */

#ifndef TCSIG
# ifdef TIOCSIG
#  define TCSIG TIOCSIG
# endif
#endif

/*
 * Send interrupt to process on other side of pty.
 * If it is in raw mode, just write NULL;
 * otherwise, write intr char.
 */
void
interrupt(void)
{
        ptyflush();     /* half-hearted */

#ifdef  TCSIG
        (void) ioctl(pty, TCSIG, SIGINT);
#else   /* TCSIG */
        init_termbuf();
        *pfrontp++ = slctab[SLC_IP].sptr ?
                        (unsigned char)*slctab[SLC_IP].sptr : '\177';
#endif  /* TCSIG */
}

/*
 * Send quit to process on other side of pty.
 * If it is in raw mode, just write NULL;
 * otherwise, write quit char.
 */
void
sendbrk(void)
{
        ptyflush();     /* half-hearted */
#ifdef  TCSIG
        (void) ioctl(pty, TCSIG, SIGQUIT);
#else   /* TCSIG */
        init_termbuf();
        *pfrontp++ = slctab[SLC_ABORT].sptr ?
                        (unsigned char)*slctab[SLC_ABORT].sptr : '\034';
#endif  /* TCSIG */
}

void
sendsusp(void)
{
#ifdef  SIGTSTP
        ptyflush();     /* half-hearted */
# ifdef TCSIG
        (void) ioctl(pty, TCSIG, SIGTSTP);
# else  /* TCSIG */
        *pfrontp++ = slctab[SLC_SUSP].sptr ?
                        (unsigned char)*slctab[SLC_SUSP].sptr : '\032';
# endif /* TCSIG */
#endif  /* SIGTSTP */
}

/*
 * When we get an AYT, if ^T is enabled, use that.  Otherwise,
 * just send back "[Yes]".
 */
void
recv_ayt(void)
{
#if     defined(SIGINFO) && defined(TCSIG)
        if (slctab[SLC_AYT].sptr && *slctab[SLC_AYT].sptr != _POSIX_VDISABLE) {
                (void) ioctl(pty, TCSIG, SIGINFO);
                return;
        }
#endif
        output_data("\r\n[Yes]\r\n");
}

void
doeof(void)
{
        init_termbuf();

#if     defined(LINEMODE) && defined(USE_TERMIO) && (VEOF == VMIN)
        if (!tty_isediting()) {
                extern char oldeofc;
                *pfrontp++ = oldeofc;
                return;
        }
#endif
        *pfrontp++ = slctab[SLC_EOF].sptr ?
                        (unsigned char)*slctab[SLC_EOF].sptr : '\004';
}