/*
 * 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.
 *
 * @(#)sys_term.c       8.4+1 (Berkeley) 5/30/95
 * $FreeBSD: src/crypto/telnet/telnetd/sys_term.c,v 1.7.2.5 2002/06/17 02:48:02 jmallett Exp $
 */

#include <sys/types.h>
#include <sys/tty.h>
#include <libutil.h>
#include <stdlib.h>
#include <utmpx.h>

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

#ifdef  AUTHENTICATION
#include <libtelnet/auth.h>
extern int      auth_level;
#endif

int cleanopen(char *);
void scrub_env(void);

char    *envinit[3];
extern char **environ;

#define SCPYN(a, b)     (void) strncpy(a, b, sizeof(a))
#define SCMPN(a, b)     strncmp(a, b, sizeof(a))

#ifdef  t_erase
#undef  t_erase
#undef  t_kill
#undef  t_intrc
#undef  t_quitc
#undef  t_startc
#undef  t_stopc
#undef  t_eofc
#undef  t_brkc
#undef  t_suspc
#undef  t_dsuspc
#undef  t_rprntc
#undef  t_flushc
#undef  t_werasc
#undef  t_lnextc
#endif

#ifndef USE_TERMIO
struct termbuf {
        struct sgttyb sg;
        struct tchars tc;
        struct ltchars ltc;
        int state;
        int lflags;
} termbuf, termbuf2;
# define        cfsetospeed(tp, val)    (tp)->sg.sg_ospeed = (val)
# define        cfsetispeed(tp, val)    (tp)->sg.sg_ispeed = (val)
# define        cfgetospeed(tp)         (tp)->sg.sg_ospeed
# define        cfgetispeed(tp)         (tp)->sg.sg_ispeed
#else   /* USE_TERMIO */
# ifndef        TCSANOW
#  ifdef TCSETS
#   define      TCSANOW         TCSETS
#   define      TCSADRAIN       TCSETSW
#   define      tcgetattr(f, t) ioctl(f, TCGETS, (char *)t)
#  else
#   ifdef TCSETA
#    define     TCSANOW         TCSETA
#    define     TCSADRAIN       TCSETAW
#    define     tcgetattr(f, t) ioctl(f, TCGETA, (char *)t)
#   else
#    define     TCSANOW         TIOCSETA
#    define     TCSADRAIN       TIOCSETAW
#    define     tcgetattr(f, t) ioctl(f, TIOCGETA, (char *)t)
#   endif
#  endif
#  define       tcsetattr(f, a, t)      ioctl(f, a, t)
#  define       cfsetospeed(tp, val)    (tp)->c_cflag &= ~CBAUD; \
                                        (tp)->c_cflag |= (val)
#  define       cfgetospeed(tp)         ((tp)->c_cflag & CBAUD)
#  ifdef CIBAUD
#   define      cfsetispeed(tp, val)    (tp)->c_cflag &= ~CIBAUD; \
                                        (tp)->c_cflag |= ((val)<<IBSHIFT)
#   define      cfgetispeed(tp)         (((tp)->c_cflag & CIBAUD)>>IBSHIFT)
#  else
#   define      cfsetispeed(tp, val)    (tp)->c_cflag &= ~CBAUD; \
                                        (tp)->c_cflag |= (val)
#   define      cfgetispeed(tp)         ((tp)->c_cflag & CBAUD)
#  endif
# endif /* TCSANOW */
struct termios termbuf, termbuf2;       /* pty control structure */
#endif  /* USE_TERMIO */

int cleanopen(char *);
void scrub_env(void);
static char **addarg(char **, const char *);

/*
 * init_termbuf()
 * copy_termbuf(cp)
 * set_termbuf()
 *
 * These three routines are used to get and set the "termbuf" structure
 * to and from the kernel.  init_termbuf() gets the current settings.
 * copy_termbuf() hands in a new "termbuf" to write to the kernel, and
 * set_termbuf() writes the structure into the kernel.
 */

void
init_termbuf(void)
{
#ifndef USE_TERMIO
        (void) ioctl(pty, TIOCGETP, (char *)&termbuf.sg);
        (void) ioctl(pty, TIOCGETC, (char *)&termbuf.tc);
        (void) ioctl(pty, TIOCGLTC, (char *)&termbuf.ltc);
# ifdef TIOCGSTATE
        (void) ioctl(pty, TIOCGSTATE, (char *)&termbuf.state);
# endif
#else
        (void) tcgetattr(pty, &termbuf);
#endif
        termbuf2 = termbuf;
}

#if     defined(LINEMODE) && defined(TIOCPKT_IOCTL)
void
copy_termbuf(char *cp, size_t len)
{
        if (len > sizeof(termbuf))
                len = sizeof(termbuf);
        memmove((char *)&termbuf, cp, len);
        termbuf2 = termbuf;
}
#endif  /* defined(LINEMODE) && defined(TIOCPKT_IOCTL) */

void
set_termbuf(void)
{
        /*
         * Only make the necessary changes.
         */
#ifndef USE_TERMIO
        if (memcmp((char *)&termbuf.sg, (char *)&termbuf2.sg,
                                                        sizeof(termbuf.sg)))
                (void) ioctl(pty, TIOCSETN, (char *)&termbuf.sg);
        if (memcmp((char *)&termbuf.tc, (char *)&termbuf2.tc,
                                                        sizeof(termbuf.tc)))
                (void) ioctl(pty, TIOCSETC, (char *)&termbuf.tc);
        if (memcmp((char *)&termbuf.ltc, (char *)&termbuf2.ltc,
                                                        sizeof(termbuf.ltc)))
                (void) ioctl(pty, TIOCSLTC, (char *)&termbuf.ltc);
        if (termbuf.lflags != termbuf2.lflags)
                (void) ioctl(pty, TIOCLSET, (char *)&termbuf.lflags);
#else   /* USE_TERMIO */
        if (memcmp((char *)&termbuf, (char *)&termbuf2, sizeof(termbuf)))
                (void) tcsetattr(pty, TCSANOW, &termbuf);
#endif  /* USE_TERMIO */
}


/*
 * spcset(func, valp, valpp)
 *
 * This function takes various special characters (func), and
 * sets *valp to the current value of that character, and
 * *valpp to point to where in the "termbuf" structure that
 * value is kept.
 *
 * It returns the SLC_ level of support for this function.
 */

#ifndef USE_TERMIO
int
spcset(int func, cc_t *valp, cc_t **valpp)
{
        switch(func) {
        case SLC_EOF:
                *valp = termbuf.tc.t_eofc;
                *valpp = (cc_t *)&termbuf.tc.t_eofc;
                return(SLC_VARIABLE);
        case SLC_EC:
                *valp = termbuf.sg.sg_erase;
                *valpp = (cc_t *)&termbuf.sg.sg_erase;
                return(SLC_VARIABLE);
        case SLC_EL:
                *valp = termbuf.sg.sg_kill;
                *valpp = (cc_t *)&termbuf.sg.sg_kill;
                return(SLC_VARIABLE);
        case SLC_IP:
                *valp = termbuf.tc.t_intrc;
                *valpp = (cc_t *)&termbuf.tc.t_intrc;
                return(SLC_VARIABLE|SLC_FLUSHIN|SLC_FLUSHOUT);
        case SLC_ABORT:
                *valp = termbuf.tc.t_quitc;
                *valpp = (cc_t *)&termbuf.tc.t_quitc;
                return(SLC_VARIABLE|SLC_FLUSHIN|SLC_FLUSHOUT);
        case SLC_XON:
                *valp = termbuf.tc.t_startc;
                *valpp = (cc_t *)&termbuf.tc.t_startc;
                return(SLC_VARIABLE);
        case SLC_XOFF:
                *valp = termbuf.tc.t_stopc;
                *valpp = (cc_t *)&termbuf.tc.t_stopc;
                return(SLC_VARIABLE);
        case SLC_AO:
                *valp = termbuf.ltc.t_flushc;
                *valpp = (cc_t *)&termbuf.ltc.t_flushc;
                return(SLC_VARIABLE);
        case SLC_SUSP:
                *valp = termbuf.ltc.t_suspc;
                *valpp = (cc_t *)&termbuf.ltc.t_suspc;
                return(SLC_VARIABLE);
        case SLC_EW:
                *valp = termbuf.ltc.t_werasc;
                *valpp = (cc_t *)&termbuf.ltc.t_werasc;
                return(SLC_VARIABLE);
        case SLC_RP:
                *valp = termbuf.ltc.t_rprntc;
                *valpp = (cc_t *)&termbuf.ltc.t_rprntc;
                return(SLC_VARIABLE);
        case SLC_LNEXT:
                *valp = termbuf.ltc.t_lnextc;
                *valpp = (cc_t *)&termbuf.ltc.t_lnextc;
                return(SLC_VARIABLE);
        case SLC_FORW1:
                *valp = termbuf.tc.t_brkc;
                *valpp = (cc_t *)&termbuf.ltc.t_lnextc;
                return(SLC_VARIABLE);
        case SLC_BRK:
        case SLC_SYNCH:
        case SLC_AYT:
        case SLC_EOR:
                *valp = (cc_t)0;
                *valpp = NULL;
                return(SLC_DEFAULT);
        default:
                *valp = (cc_t)0;
                *valpp = NULL;
                return(SLC_NOSUPPORT);
        }
}

#else   /* USE_TERMIO */


#define setval(a, b)    *valp = termbuf.c_cc[a]; \
                        *valpp = &termbuf.c_cc[a]; \
                        return(b);
#define defval(a) *valp = ((cc_t)a); *valpp = NULL; return(SLC_DEFAULT);

int
spcset(int func, cc_t *valp, cc_t **valpp)
{
        switch(func) {
        case SLC_EOF:
                setval(VEOF, SLC_VARIABLE);
        case SLC_EC:
                setval(VERASE, SLC_VARIABLE);
        case SLC_EL:
                setval(VKILL, SLC_VARIABLE);
        case SLC_IP:
                setval(VINTR, SLC_VARIABLE|SLC_FLUSHIN|SLC_FLUSHOUT);
        case SLC_ABORT:
                setval(VQUIT, SLC_VARIABLE|SLC_FLUSHIN|SLC_FLUSHOUT);
        case SLC_XON:
#ifdef  VSTART
                setval(VSTART, SLC_VARIABLE);
#else
                defval(0x13);
#endif
        case SLC_XOFF:
#ifdef  VSTOP
                setval(VSTOP, SLC_VARIABLE);
#else
                defval(0x11);
#endif
        case SLC_EW:
#ifdef  VWERASE
                setval(VWERASE, SLC_VARIABLE);
#else
                defval(0);
#endif
        case SLC_RP:
#ifdef  VREPRINT
                setval(VREPRINT, SLC_VARIABLE);
#else
                defval(0);
#endif
        case SLC_LNEXT:
#ifdef  VLNEXT
                setval(VLNEXT, SLC_VARIABLE);
#else
                defval(0);
#endif
        case SLC_AO:
#if     !defined(VDISCARD) && defined(VFLUSHO)
# define VDISCARD VFLUSHO
#endif
#ifdef  VDISCARD
                setval(VDISCARD, SLC_VARIABLE|SLC_FLUSHOUT);
#else
                defval(0);
#endif
        case SLC_SUSP:
#ifdef  VSUSP
                setval(VSUSP, SLC_VARIABLE|SLC_FLUSHIN);
#else
                defval(0);
#endif
#ifdef  VEOL
        case SLC_FORW1:
                setval(VEOL, SLC_VARIABLE);
#endif
#ifdef  VEOL2
        case SLC_FORW2:
                setval(VEOL2, SLC_VARIABLE);
#endif
        case SLC_AYT:
#ifdef  VSTATUS
                setval(VSTATUS, SLC_VARIABLE);
#else
                defval(0);
#endif

        case SLC_BRK:
        case SLC_SYNCH:
        case SLC_EOR:
                defval(0);

        default:
                *valp = 0;
                *valpp = NULL;
                return(SLC_NOSUPPORT);
        }
}
#endif  /* USE_TERMIO */

/*
 * getpty()
 *
 * Allocate a pty.  As a side effect, the external character
 * array "line" contains the name of the slave side.
 *
 * Returns the file descriptor of the opened pty.
 */
char alpha[] = "0123456789abcdefghijklmnopqrstuv";
char line[16];

int
getpty(int *ptynum __unused)
{
        int p;
        const char *cp;
        char *p1, *p2;
        int i;

        (void) strcpy(line, _PATH_DEV);
        (void) strcat(line, "ptyXX");
        p1 = &line[8];
        p2 = &line[9];

        for (cp = "pqrsPQRS"; *cp; cp++) {
                struct stat stb;

                *p1 = *cp;
                *p2 = '0';
                /*
                 * This stat() check is just to keep us from
                 * looping through all 256 combinations if there
                 * aren't that many ptys available.
                 */
                if (stat(line, &stb) < 0)
                        break;
                for (i = 0; i < 32; i++) {
                        *p2 = alpha[i];
                        p = open(line, 2);
                        if (p > 0) {
                                line[5] = 't';
                                chown(line, 0, 0);
                                chmod(line, 0600);
                                        return(p);
                        }
                }
        }
        return(-1);
}

#ifdef  LINEMODE
/*
 * tty_flowmode()       Find out if flow control is enabled or disabled.
 * tty_linemode()       Find out if linemode (external processing) is enabled.
 * tty_setlinemod(on)   Turn on/off linemode.
 * tty_isecho()         Find out if echoing is turned on.
 * tty_setecho(on)      Enable/disable character echoing.
 * tty_israw()          Find out if terminal is in RAW mode.
 * tty_binaryin(on)     Turn on/off BINARY on input.
 * tty_binaryout(on)    Turn on/off BINARY on output.
 * tty_isediting()      Find out if line editing is enabled.
 * tty_istrapsig()      Find out if signal trapping is enabled.
 * tty_setedit(on)      Turn on/off line editing.
 * tty_setsig(on)       Turn on/off signal trapping.
 * tty_issofttab()      Find out if tab expansion is enabled.
 * tty_setsofttab(on)   Turn on/off soft tab expansion.
 * tty_islitecho()      Find out if typed control chars are echoed literally
 * tty_setlitecho()     Turn on/off literal echo of control chars
 * tty_tspeed(val)      Set transmit speed to val.
 * tty_rspeed(val)      Set receive speed to val.
 */


int
tty_linemode(void)
{
#ifndef USE_TERMIO
        return(termbuf.state & TS_EXTPROC);
#else
        return(termbuf.c_lflag & EXTPROC);
#endif
}

void
tty_setlinemode(int on)
{
#ifdef  TIOCEXT
        set_termbuf();
        (void) ioctl(pty, TIOCEXT, (char *)&on);
        init_termbuf();
#else   /* !TIOCEXT */
# ifdef EXTPROC
        if (on)
                termbuf.c_lflag |= EXTPROC;
        else
                termbuf.c_lflag &= ~EXTPROC;
# endif
#endif  /* TIOCEXT */
}
#endif  /* LINEMODE */

int
tty_isecho(void)
{
#ifndef USE_TERMIO
        return (termbuf.sg.sg_flags & ECHO);
#else
        return (termbuf.c_lflag & ECHO);
#endif
}

int
tty_flowmode(void)
{
#ifndef USE_TERMIO
        return(((termbuf.tc.t_startc) > 0 && (termbuf.tc.t_stopc) > 0) ? 1 : 0);
#else
        return((termbuf.c_iflag & IXON) ? 1 : 0);
#endif
}

int
tty_restartany(void)
{
#ifndef USE_TERMIO
# ifdef DECCTQ
        return((termbuf.lflags & DECCTQ) ? 0 : 1);
# else
        return(-1);
# endif
#else
        return((termbuf.c_iflag & IXANY) ? 1 : 0);
#endif
}

void
tty_setecho(int on)
{
#ifndef USE_TERMIO
        if (on)
                termbuf.sg.sg_flags |= ECHO|CRMOD;
        else
                termbuf.sg.sg_flags &= ~(ECHO|CRMOD);
#else
        if (on)
                termbuf.c_lflag |= ECHO;
        else
                termbuf.c_lflag &= ~ECHO;
#endif
}

int
tty_israw(void)
{
#ifndef USE_TERMIO
        return(termbuf.sg.sg_flags & RAW);
#else
        return(!(termbuf.c_lflag & ICANON));
#endif
}

#ifdef  AUTHENTICATION
#if     defined(NO_LOGIN_F) && defined(LOGIN_R)
int
tty_setraw(int on)
{
#  ifndef USE_TERMIO
        if (on)
                termbuf.sg.sg_flags |= RAW;
        else
                termbuf.sg.sg_flags &= ~RAW;
#  else
        if (on)
                termbuf.c_lflag &= ~ICANON;
        else
                termbuf.c_lflag |= ICANON;
#  endif
}
#endif
#endif /* AUTHENTICATION */

void
tty_binaryin(int on)
{
#ifndef USE_TERMIO
        if (on)
                termbuf.lflags |= LPASS8;
        else
                termbuf.lflags &= ~LPASS8;
#else
        if (on) {
                termbuf.c_iflag &= ~ISTRIP;
        } else {
                termbuf.c_iflag |= ISTRIP;
        }
#endif
}

void
tty_binaryout(int on)
{
#ifndef USE_TERMIO
        if (on)
                termbuf.lflags |= LLITOUT;
        else
                termbuf.lflags &= ~LLITOUT;
#else
        if (on) {
                termbuf.c_cflag &= ~(CSIZE|PARENB);
                termbuf.c_cflag |= CS8;
                termbuf.c_oflag &= ~OPOST;
        } else {
                termbuf.c_cflag &= ~CSIZE;
                termbuf.c_cflag |= CS7|PARENB;
                termbuf.c_oflag |= OPOST;
        }
#endif
}

int
tty_isbinaryin(void)
{
#ifndef USE_TERMIO
        return(termbuf.lflags & LPASS8);
#else
        return(!(termbuf.c_iflag & ISTRIP));
#endif
}

int
tty_isbinaryout(void)
{
#ifndef USE_TERMIO
        return(termbuf.lflags & LLITOUT);
#else
        return(!(termbuf.c_oflag&OPOST));
#endif
}

#ifdef  LINEMODE
int
tty_isediting(void)
{
#ifndef USE_TERMIO
        return(!(termbuf.sg.sg_flags & (CBREAK|RAW)));
#else
        return(termbuf.c_lflag & ICANON);
#endif
}

int
tty_istrapsig(void)
{
#ifndef USE_TERMIO
        return(!(termbuf.sg.sg_flags&RAW));
#else
        return(termbuf.c_lflag & ISIG);
#endif
}

void
tty_setedit(int on)
{
#ifndef USE_TERMIO
        if (on)
                termbuf.sg.sg_flags &= ~CBREAK;
        else
                termbuf.sg.sg_flags |= CBREAK;
#else
        if (on)
                termbuf.c_lflag |= ICANON;
        else
                termbuf.c_lflag &= ~ICANON;
#endif
}

void
tty_setsig(int on)
{
#ifndef USE_TERMIO
        if (on)
                ;
#else
        if (on)
                termbuf.c_lflag |= ISIG;
        else
                termbuf.c_lflag &= ~ISIG;
#endif
}
#endif  /* LINEMODE */

int
tty_issofttab(void)
{
#ifndef USE_TERMIO
        return (termbuf.sg.sg_flags & XTABS);
#else
# ifdef OXTABS
        return (termbuf.c_oflag & OXTABS);
# endif
# ifdef TABDLY
        return ((termbuf.c_oflag & TABDLY) == TAB3);
# endif
#endif
}

void
tty_setsofttab(int on)
{
#ifndef USE_TERMIO
        if (on)
                termbuf.sg.sg_flags |= XTABS;
        else
                termbuf.sg.sg_flags &= ~XTABS;
#else
        if (on) {
# ifdef OXTABS
                termbuf.c_oflag |= OXTABS;
# endif
# ifdef TABDLY
                termbuf.c_oflag &= ~TABDLY;
                termbuf.c_oflag |= TAB3;
# endif
        } else {
# ifdef OXTABS
                termbuf.c_oflag &= ~OXTABS;
# endif
# ifdef TABDLY
                termbuf.c_oflag &= ~TABDLY;
                termbuf.c_oflag |= TAB0;
# endif
        }
#endif
}

int
tty_islitecho(void)
{
#ifndef USE_TERMIO
        return (!(termbuf.lflags & LCTLECH));
#else
# ifdef ECHOCTL
        return (!(termbuf.c_lflag & ECHOCTL));
# endif
# ifdef TCTLECH
        return (!(termbuf.c_lflag & TCTLECH));
# endif
# if    !defined(ECHOCTL) && !defined(TCTLECH)
        return (0);     /* assumes ctl chars are echoed '^x' */
# endif
#endif
}

void
tty_setlitecho(int on)
{
#ifndef USE_TERMIO
        if (on)
                termbuf.lflags &= ~LCTLECH;
        else
                termbuf.lflags |= LCTLECH;
#else
# ifdef ECHOCTL
        if (on)
                termbuf.c_lflag &= ~ECHOCTL;
        else
                termbuf.c_lflag |= ECHOCTL;
# endif
# ifdef TCTLECH
        if (on)
                termbuf.c_lflag &= ~TCTLECH;
        else
                termbuf.c_lflag |= TCTLECH;
# endif
#endif
}

int
tty_iscrnl(void)
{
#ifndef USE_TERMIO
        return (termbuf.sg.sg_flags & CRMOD);
#else
        return (termbuf.c_iflag & ICRNL);
#endif
}

/*
 * Try to guess whether speeds are "encoded" (4.2BSD) or just numeric (4.4BSD).
 */
#if B4800 != 4800
#define DECODE_BAUD
#endif

#ifdef  DECODE_BAUD

/*
 * A table of available terminal speeds
 */
struct termspeeds {
        int     speed;
        int     value;
} termspeeds[] = {
        { 0,      B0 },      { 50,    B50 },    { 75,     B75 },
        { 110,    B110 },    { 134,   B134 },   { 150,    B150 },
        { 200,    B200 },    { 300,   B300 },   { 600,    B600 },
        { 1200,   B1200 },   { 1800,  B1800 },  { 2400,   B2400 },
        { 4800,   B4800 },
#ifdef  B7200
        { 7200,  B7200 },
#endif
        { 9600,   B9600 },
#ifdef  B14400
        { 14400,  B14400 },
#endif
#ifdef  B19200
        { 19200,  B19200 },
#endif
#ifdef  B28800
        { 28800,  B28800 },
#endif
#ifdef  B38400
        { 38400,  B38400 },
#endif
#ifdef  B57600
        { 57600,  B57600 },
#endif
#ifdef  B115200
        { 115200, B115200 },
#endif
#ifdef  B230400
        { 230400, B230400 },
#endif
        { -1,     0 }
};
#endif  /* DECODE_BAUD */

void
tty_tspeed(int val)
{
#ifdef  DECODE_BAUD
        struct termspeeds *tp;

        for (tp = termspeeds; (tp->speed != -1) && (val > tp->speed); tp++)
                ;
        if (tp->speed == -1)    /* back up to last valid value */
                --tp;
        cfsetospeed(&termbuf, tp->value);
#else   /* DECODE_BAUD */
        cfsetospeed(&termbuf, val);
#endif  /* DECODE_BAUD */
}

void
tty_rspeed(int val)
{
#ifdef  DECODE_BAUD
        struct termspeeds *tp;

        for (tp = termspeeds; (tp->speed != -1) && (val > tp->speed); tp++)
                ;
        if (tp->speed == -1)    /* back up to last valid value */
                --tp;
        cfsetispeed(&termbuf, tp->value);
#else   /* DECODE_BAUD */
        cfsetispeed(&termbuf, val);
#endif  /* DECODE_BAUD */
}

/*
 * getptyslave()
 *
 * Open the slave side of the pty, and do any initialization
 * that is necessary.
 */
static void
getptyslave(void)
{
        int t = -1;
        char erase;

# ifdef LINEMODE
        int waslm;
# endif
# ifdef TIOCGWINSZ
        struct winsize ws;
        extern int def_row, def_col;
# endif
        extern int def_tspeed, def_rspeed;
        /*
         * Opening the slave side may cause initilization of the
         * kernel tty structure.  We need remember the state of
         *      if linemode was turned on
         *      terminal window size
         *      terminal speed
         *      erase character
         * so that we can re-set them if we need to.
         */
# ifdef LINEMODE
        waslm = tty_linemode();
# endif
        erase = termbuf.c_cc[VERASE];

        /*
         * Make sure that we don't have a controlling tty, and
         * that we are the session (process group) leader.
         */
# ifdef TIOCNOTTY
        t = open(_PATH_TTY, O_RDWR);
        if (t >= 0) {
                (void) ioctl(t, TIOCNOTTY, NULL);
                (void) close(t);
        }
# endif

        t = cleanopen(line);
        if (t < 0)
                fatalperror(net, line);


        /*
         * set up the tty modes as we like them to be.
         */
        init_termbuf();
# ifdef TIOCGWINSZ
        if (def_row || def_col) {
                memset((char *)&ws, 0, sizeof(ws));
                ws.ws_col = def_col;
                ws.ws_row = def_row;
                (void)ioctl(t, TIOCSWINSZ, (char *)&ws);
        }
# endif

        /*
         * Settings for sgtty based systems
         */
# ifndef        USE_TERMIO
        termbuf.sg.sg_flags |= CRMOD|ANYP|ECHO|XTABS;
# endif /* USE_TERMIO */

        /*
         * Settings for all other termios/termio based
         * systems, other than 4.4BSD.  In 4.4BSD the
         * kernel does the initial terminal setup.
         */
        tty_rspeed((def_rspeed > 0) ? def_rspeed : 9600);
        tty_tspeed((def_tspeed > 0) ? def_tspeed : 9600);
        if (erase)
                termbuf.c_cc[VERASE] = erase;
# ifdef LINEMODE
        if (waslm)
                tty_setlinemode(1);
# endif /* LINEMODE */

        /*
         * Set the tty modes, and make this our controlling tty.
         */
        set_termbuf();
        if (login_tty(t) == -1)
                fatalperror(net, "login_tty");
        if (net > 2)
                (void) close(net);
#ifdef  AUTHENTICATION
#if     defined(NO_LOGIN_F) && defined(LOGIN_R)
        /*
         * Leave the pty open so that we can write out the rlogin
         * protocol for /bin/login, if the authentication works.
         */
#else
        if (pty > 2) {
                (void) close(pty);
                pty = -1;
        }
#endif
#endif /* AUTHENTICATION */
}

#ifndef O_NOCTTY
#define O_NOCTTY        0
#endif
/*
 * Open the specified slave side of the pty,
 * making sure that we have a clean tty.
 */
int
cleanopen(char *li)
{
        int t;

        /*
         * Make sure that other people can't open the
         * slave side of the connection.
         */
        (void) chown(li, 0, 0);
        (void) chmod(li, 0600);

        (void) revoke(li);

        t = open(line, O_RDWR|O_NOCTTY);

        if (t < 0)
                return(-1);

        return(t);
}

/*
 * startslave(host)
 *
 * Given a hostname, do whatever
 * is necessary to startup the login process on the slave side of the pty.
 */

/* ARGSUSED */
void
startslave(char *host, int autologin, char *autoname)
{
        int i;

#ifdef  AUTHENTICATION
        if (!autoname || !autoname[0])
                autologin = 0;

        if (autologin < auth_level) {
                fatalmsg(net, "Authorization failed");
                exit(1);
        }
#endif


        if ((i = fork()) < 0)
                fatalperror(net, "fork");
        if (i) {
        } else {
                getptyslave();
                start_login(host, autologin, autoname);
                /*NOTREACHED*/
        }
}

void
init_env(void)
{
        char **envp;

        envp = envinit;
        if ((*envp = getenv("TZ")))
                *envp++ -= 3;
        *envp = NULL;
        environ = envinit;
}


/*
 * start_login(host)
 *
 * Assuming that we are now running as a child processes, this
 * function will turn us into the login process.
 */

#ifndef AUTHENTICATION
#define undef1 __unused
#else
#define undef1
#endif

void
start_login(char *host undef1, int autologin undef1, char *name undef1)
{
        char **argv;

        scrub_env();

        /*
         * -h : pass on name of host.
         *              WARNING:  -h is accepted by login if and only if
         *                      getuid() == 0.
         * -p : don't clobber the environment (so terminal type stays set).
         *
         * -f : force this login, he has already been authenticated
         */
        argv = addarg(0, "login");

#if     !defined(NO_LOGIN_H)
#ifdef  AUTHENTICATION
# if    defined(NO_LOGIN_F) && defined(LOGIN_R)
        /*
         * Don't add the "-h host" option if we are going
         * to be adding the "-r host" option down below...
         */
        if ((auth_level < 0) || (autologin != AUTH_VALID))
# endif
        {
                argv = addarg(argv, "-h");
                argv = addarg(argv, host);
        }
#endif /* AUTHENTICATION */
#endif
#if     !defined(NO_LOGIN_P)
        argv = addarg(argv, "-p");
#endif
#ifdef  LINEMODE
        /*
         * Set the environment variable "LINEMODE" to either
         * "real" or "kludge" if we are operating in either
         * real or kludge linemode.
         */
        if (lmodetype == REAL_LINEMODE) {
                if (setenv("LINEMODE", "real", 1) == -1)
                        syslog(LOG_ERR, "setenv: cannot set LINEMODE=real: %m");
        }
# ifdef KLUDGELINEMODE
        else if (lmodetype == KLUDGE_LINEMODE || lmodetype == KLUDGE_OK) {
                if (setenv("LINEMODE", "kludge", 1) == -1)
                        syslog(LOG_ERR, "setenv: cannot set LINEMODE=kludge: %m");
        }
# endif
#endif
#ifdef  BFTPDAEMON
        /*
         * Are we working as the bftp daemon?  If so, then ask login
         * to start bftp instead of shell.
         */
        if (bftpd) {
                argv = addarg(argv, "-e");
                argv = addarg(argv, BFTPPATH);
        } else
#endif
#ifdef  AUTHENTICATION
        if (auth_level >= 0 && autologin == AUTH_VALID) {
# if    !defined(NO_LOGIN_F)
                argv = addarg(argv, "-f");
                argv = addarg(argv, "--");
                argv = addarg(argv, name);
# else
#  if defined(LOGIN_R)
                /*
                 * We don't have support for "login -f", but we
                 * can fool /bin/login into thinking that we are
                 * rlogind, and allow us to log in without a
                 * password.  The rlogin protocol expects
                 *      local-user\0remote-user\0term/speed\0
                 */

                if (pty > 2) {
                        char *cp;
                        char speed[128];
                        int isecho, israw, xpty, len;
                        extern int def_rspeed;
#  ifndef LOGIN_HOST
                        /*
                         * Tell login that we are coming from "localhost".
                         * If we passed in the real host name, then the
                         * user would have to allow .rhost access from
                         * every machine that they want authenticated
                         * access to work from, which sort of defeats
                         * the purpose of an authenticated login...
                         * So, we tell login that the session is coming
                         * from "localhost", and the user will only have
                         * to have "localhost" in their .rhost file.
                         */
#                       define LOGIN_HOST "localhost"
#  endif
                        argv = addarg(argv, "-r");
                        argv = addarg(argv, LOGIN_HOST);

                        xpty = pty;
                        pty = 0;
                        init_termbuf();
                        isecho = tty_isecho();
                        israw = tty_israw();
                        if (isecho || !israw) {
                                tty_setecho(0);         /* Turn off echo */
                                tty_setraw(1);          /* Turn on raw */
                                set_termbuf();
                        }
                        len = strlen(name)+1;
                        write(xpty, name, len);
                        write(xpty, name, len);
                        snprintf(speed, sizeof(speed),
                                "%s/%d", (cp = getenv("TERM")) ? cp : "",
                                (def_rspeed > 0) ? def_rspeed : 9600);
                        len = strlen(speed)+1;
                        write(xpty, speed, len);

                        if (isecho || !israw) {
                                init_termbuf();
                                tty_setecho(isecho);
                                tty_setraw(israw);
                                set_termbuf();
                                if (!israw) {
                                        /*
                                         * Write a newline to ensure
                                         * that login will be able to
                                         * read the line...
                                         */
                                        write(xpty, "\n", 1);
                                }
                        }
                        pty = xpty;
                }
#  else
                argv = addarg(argv, "--");
                argv = addarg(argv, name);
#  endif
# endif
        } else
#endif
        if (getenv("USER")) {
                argv = addarg(argv, "--");
                argv = addarg(argv, getenv("USER"));
#if     defined(LOGIN_ARGS) && defined(NO_LOGIN_P)
                {
                        char **cpp;
                        for (cpp = environ; *cpp; cpp++)
                                argv = addarg(argv, *cpp);
                }
#endif
                /*
                 * Assume that login will set the USER variable
                 * correctly.  For SysV systems, this means that
                 * USER will no longer be set, just LOGNAME by
                 * login.  (The problem is that if the auto-login
                 * fails, and the user then specifies a different
                 * account name, he can get logged in with both
                 * LOGNAME and USER in his environment, but the
                 * USER value will be wrong.
                 */
                unsetenv("USER");
        }
#ifdef  AUTHENTICATION
#if     defined(NO_LOGIN_F) && defined(LOGIN_R)
        if (pty > 2)
                close(pty);
#endif
#endif /* AUTHENTICATION */
        closelog();

        if (altlogin == NULL) {
                altlogin = _PATH_LOGIN;
        }
        execv(altlogin, argv);

        syslog(LOG_ERR, "%s: %m", altlogin);
        fatalperror(net, altlogin);
        /*NOTREACHED*/
}

static char **
addarg(char **argv, const char *val)
{
        char **cpp;

        if (argv == NULL) {
                /*
                 * 10 entries, a leading length, and a null
                 */
                argv = (char **)malloc(sizeof(*argv) * 12);
                if (argv == NULL)
                        return(NULL);
                *argv++ = (char *)10;
                *argv = NULL;
        }
        for (cpp = argv; *cpp; cpp++)
                ;
        if (cpp == &argv[(long)argv[-1]]) {
                --argv;
                *argv = (char *)((long)(*argv) + 10);
                argv = (char **)realloc(argv, sizeof(*argv)*((long)(*argv) + 2));
                if (argv == NULL)
                        return(NULL);
                argv++;
                cpp = &argv[(long)argv[-1] - 10];
        }
        *cpp++ = strdup(val);
        *cpp = NULL;
        return(argv);
}

/*
 * scrub_env()
 *
 * We only accept the environment variables listed below.
 */
void
scrub_env(void)
{
        static const char *rej[] = {
                "TERMCAP=/",
                NULL
        };

        static const char *acc[] = {
                "XAUTH=", "XAUTHORITY=", "DISPLAY=",
                "TERM=",
                "EDITOR=",
                "PAGER=",
                "LOGNAME=",
                "POSIXLY_CORRECT=",
                "PRINTER=",
                NULL
        };

        char **cpp, **cpp2;
        const char **p;
        char ** new_environ;
        size_t count;

        /* Allocate space for scrubbed environment. */
        for (count = 1, cpp = environ; *cpp; count++, cpp++)
                continue;
        if ((new_environ = malloc(count * sizeof(char *))) == NULL) {
                environ = NULL;
                return;
        }

        for (cpp2 = new_environ, cpp = environ; *cpp; cpp++) {
                int reject_it = 0;

                for(p = rej; *p; p++)
                        if(strncmp(*cpp, *p, strlen(*p)) == 0) {
                                reject_it = 1;
                                break;
                        }
                if (reject_it)
                        continue;

                for(p = acc; *p; p++)
                        if(strncmp(*cpp, *p, strlen(*p)) == 0)
                                break;
                if(*p != NULL) {
                        if ((*cpp2++ = strdup(*cpp)) == NULL) {
                                environ = new_environ;
                                return;
                        }
                }
        }
        *cpp2 = NULL;
        environ = new_environ;
}

/*
 * cleanup()
 *
 * This is the routine to call when we are all through, to
 * clean up anything that needs to be cleaned up.
 */
/* ARGSUSED */
void
cleanup(int sig __unused)
{
        char *p;
        sigset_t mask;

        p = line + sizeof(_PATH_DEV) - 1;
        /*
         * Block all signals before clearing the utmpx entry.  We don't want to
         * be called again after calling logout() and then not add the wtmpx
         * entry because of not finding the corresponding entry in utmpx.
         */
        sigfillset(&mask);
        sigprocmask(SIG_SETMASK, &mask, NULL);
        if (logoutx(p, 0, DEAD_PROCESS))
                logwtmpx(p, "", "", 0, DEAD_PROCESS);
        (void)chmod(line, 0666);
        (void)chown(line, 0, 0);
        *p = 'p';
        (void)chmod(line, 0666);
        (void)chown(line, 0, 0);
        (void) shutdown(net, SHUT_RDWR);
        _exit(1);
}