/*
 * Copyright (c) 1989 Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*
 * From: @(#)sys_term.c	5.16 (Berkeley) 3/22/91
 */
char st_rcsid[] = 
  "$Id: sys_term.c,v 1.16 1999/12/12 14:59:45 dholland Exp $";

#include <utmp.h>

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

#if defined(__GLIBC__) && (__GLIBC__ >= 2)
/* mmm, nonstandard */
#include <pty.h>
#else
int openpty(int *, int *, char *, struct termios *, struct winsize *);
#endif

#define ARCH64 ((sizeof(void *)) == 8)
#define ARCH32 ((sizeof(void *)) == 4)

#if defined(AUTHENTICATE)
#include <libtelnet/auth.h>
#endif

static struct termios termbuf, termbuf2;	/* pty control structure */

/*static int cleanopen(char *line);*/

/*
 * 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) {
    tcgetattr(pty, &termbuf);
    termbuf2 = termbuf;
}

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

void set_termbuf(void) {
    if (memcmp(&termbuf, &termbuf2, sizeof(termbuf))) {
	tcsetattr(pty, TCSANOW, &termbuf);
    }
}


/*
 * 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.
 */


int spcset(int func, cc_t *valp, cc_t **valpp) {

#define	setval(a, b)	*valp = termbuf.c_cc[a]; \
			*valpp = &termbuf.c_cc[a]; \
			return(b);
#define	defval(a) *valp = ((cc_t)a); *valpp = (cc_t *)0; return(SLC_DEFAULT);

    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 = 0;
	return(SLC_NOSUPPORT);
    }
}

/*
 * 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.
 */
static char linedata[PATH_MAX];
char *line = linedata;

static int ptyslavefd=-1;

int getpty(void) {
    int masterfd;

    if (openpty(&masterfd, &ptyslavefd, line, NULL, NULL)) {
	return -1;
    }
    return masterfd;
}

#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_flowmode(void) {
    return (termbuf.c_iflag & IXON ? 1 : 0);
}

int tty_linemode(void) {
    return (termbuf.c_lflag & EXTPROC);
}

void tty_setlinemode(int on) {
#ifdef TIOCEXT
    set_termbuf();
    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 */
}

int tty_isecho(void) {
    return (termbuf.c_lflag & ECHO);
}
#endif	/* LINEMODE */

void tty_setecho(int on) {
    if (on) termbuf.c_lflag |= ECHO;
    else termbuf.c_lflag &= ~ECHO;
}

#if defined(LINEMODE) && defined(KLUDGELINEMODE)
int tty_israw(void) {
    return(!(termbuf.c_lflag & ICANON));
}
#endif	/* defined(LINEMODE) && defined(KLUDGELINEMODE) */

void tty_binaryin(int on) {
    if (on) {
	termbuf.c_iflag &= ~ISTRIP;
    }
    else {
	termbuf.c_iflag |= ISTRIP;
    }
}

void tty_binaryout(int on) {
    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;
    }
}

int tty_isbinaryin(void) {
    return (!(termbuf.c_iflag & ISTRIP));
}

int tty_isbinaryout(void) {
    return (!(termbuf.c_oflag&OPOST));
}

#ifdef	LINEMODE
int tty_isediting(void) {
    return(termbuf.c_lflag & ICANON);
}

int tty_istrapsig(void) {
    return(termbuf.c_lflag & ISIG);
}

void tty_setedit(int on) {
    if (on) termbuf.c_lflag |= ICANON;
    else termbuf.c_lflag &= ~ICANON;
}

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

int tty_issofttab(void) {
#ifdef OXTABS
    return (termbuf.c_oflag & OXTABS);
#endif
#ifdef TABDLY
    return ((termbuf.c_oflag & TABDLY) == TAB3);
#endif
}

void tty_setsofttab(int on) {
    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
    }
}

int tty_islitecho(void) {
    return (!(termbuf.c_lflag & ECHOCTL));
}

void tty_setlitecho(int on) {
    if (on) termbuf.c_lflag &= ~ECHOCTL;
    else termbuf.c_lflag |= ECHOCTL;
}

int tty_iscrnl(void) {
    return (termbuf.c_iflag & ICRNL);
}

/*
 * 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 }, { 9600,  B9600 }, { 19200, B9600 },
	{ 38400, B9600 }, { -1,    B9600 }
};

void tty_tspeed(int val) {
    struct termspeeds *tp;
    for (tp = termspeeds; (tp->speed != -1) && (val > tp->speed); tp++);
    cfsetospeed(&termbuf, tp->value);
}

void tty_rspeed(int val) {
    struct termspeeds *tp;
    for (tp = termspeeds; (tp->speed != -1) && (val > tp->speed); tp++);
    cfsetispeed(&termbuf, tp->value);
}

/*
 * getptyslave()
 *
 * Open the slave side of the pty, and do any initialization
 * that is necessary.  The return value is a file descriptor
 * for the slave side.
 */
#ifdef	TIOCGWINSZ
extern int def_row, def_col;
#endif
extern int def_tspeed, def_rspeed;

static int getptyslave(void) {
#if 0
    register int t = -1;

# ifdef	LINEMODE
    int waslm;
# endif
# ifdef	TIOCGWINSZ
    struct winsize ws;
# endif
    /*
     * 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
     * so that we can re-set them if we need to.
     */
# ifdef	LINEMODE
    waslm = tty_linemode();
# endif


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

    t = cleanopen(line);
    if (t < 0) fatalperror(net, line);
#endif /* 0 */

    struct winsize ws;
    int t = ptyslavefd;

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

    /*
     * Settings for all other termios/termio based
     * systems, other than 4.4BSD.  In 4.4BSD the
     * kernel does the initial terminal setup.
     *
     * XXX what about linux?
     */
#  ifndef	OXTABS
#   define OXTABS	0
#  endif
    termbuf.c_lflag |= ECHO;
    termbuf.c_oflag |= OPOST|ONLCR|OXTABS;
    termbuf.c_iflag |= ICRNL;
    termbuf.c_iflag &= ~IXOFF;

    tty_rspeed((def_rspeed > 0) ? def_rspeed : 9600);
    tty_tspeed((def_tspeed > 0) ? def_tspeed : 9600);
# 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) close(net);
    if (pty > 2) close(pty);
    return t;
}

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

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

#ifndef NO_REVOKE
    revoke(lyne);
#endif

    t = open(lyne, O_RDWR|O_NOCTTY);
    if (t < 0) return(-1);

    /*
     * Hangup anybody else using this ttyp, then reopen it for
     * ourselves.
     */
# if !defined(__linux__)
    /* this looks buggy to me, our ctty is really a pty at this point */
    signal(SIGHUP, SIG_IGN);
    vhangup();
    signal(SIGHUP, SIG_DFL);
    t = open(lyne, O_RDWR|O_NOCTTY);
    if (t < 0) return(-1);
# endif
    return(t);
}
#endif /* 0 */

int login_tty(int t) {
    if (setsid() < 0) fatalperror(net, "setsid()");
    if (ioctl(t, TIOCSCTTY, (char *)0) < 0) {
	fatalperror(net, "ioctl(sctty)");
    }
    if (t != 0) dup2(t, 0);
    if (t != 1) dup2(t, 1);
    if (t != 2) dup2(t, 2);
    if (t > 2) close(t);
    return 0;
}

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

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

#if defined(AUTHENTICATE)
    if (!autoname || !autoname[0]) autologin = 0;
    if (autologin < auth_level) {
	fatal(net, "Authorization failed");
	exit(1);
    }
#endif

    i = fork();
    if (i < 0) fatalperror(net, "fork");
    if (i) {
	/* parent */
	signal(SIGHUP,SIG_IGN);
	close(ptyslavefd);
    } 
    else {
	/* child */
	signal(SIGHUP,SIG_IGN);
	getptyslave();
	start_login(host, autologin, autoname);
	/*NOTREACHED*/
    }
}

char *envinit[3];

void init_env(void) {
    char **envp;
    envp = envinit;
    if ((*envp = getenv("TZ"))!=NULL)
	*envp++ -= 3;
    *envp = 0;
    environ = envinit;
}

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

struct argv_stuff {
   const char **argv;
   int argc;
   int argmax;
};

static void addarg(struct argv_stuff *, const char *);
static void initarg(struct argv_stuff *);

void start_login(const char *host, int autologin, const char *name) {
    struct argv_stuff avs;
    char *const *argvfoo;
    (void)autologin;

    initarg(&avs);

    /*
     * -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
     */
    addarg(&avs, loginprg);
    addarg(&avs, "-h");
    addarg(&avs, host);
#if !defined(NO_LOGIN_P)
    addarg(&avs, "-p");
#endif
#ifdef BFTPDAEMON
    /*
     * Are we working as the bftp daemon?  If so, then ask login
     * to start bftp instead of shell.
     */
    if (bftpd) {
	addarg(&avs, "-e");
	addarg(&avs, BFTPPATH);
    } 
    else
#endif
    {
#if defined (SecurID)
	/*
	 * don't worry about the -f that might get sent.
	 * A -s is supposed to override it anyhow.
	 */
	if (require_SecurID) addarg(&avs, "-s");
#endif
	if (*name=='-') {
	    syslog(LOG_ERR, "Attempt to login with an option!");
	    name = "";
	}
#if defined (AUTHENTICATE)
	if (auth_level >= 0 && autologin == AUTH_VALID) {
# if !defined(NO_LOGIN_F)
	    addarg(&avs, "-f");
# endif
	    addarg(&avs, name);
	} 
	else
#endif
	{
	    if (getenv("USER")) {
		addarg(&avs, getenv("USER"));
		if (*getenv("USER") == '-') {
		    write(1,"I don't hear you!\r\n",19);
		    syslog(LOG_ERR,"Attempt to login with an option!");
		    exit(1);
		}
	    }
	}
    }
    closelog();
    /* execv() should really take char const* const *, but it can't */ 
    /*argvfoo = argv*/;
    memcpy(&argvfoo, &avs.argv, sizeof(argvfoo));
    execv(loginprg, argvfoo);

    openlog("telnetd", LOG_PID | LOG_ODELAY, LOG_DAEMON);
    syslog(LOG_ERR, "%s: %m\n", loginprg);
    closelog();
    fatalperror(net, loginprg);
}

static void initarg(struct argv_stuff *avs) {
   /*
    * 10 entries and a null
    */
   avs->argmax = 11;
   avs->argv = malloc(sizeof(avs->argv[0]) * avs->argmax);
   if (avs->argv == NULL) {
      fprintf(stderr, "Out of memory\n");
      exit(1);
   }
   avs->argc = 0;
   avs->argv[0] = NULL;
}

static void addarg(struct argv_stuff *avs, const char *val) {
   if (avs->argc>=avs->argmax-1) {
       avs->argmax += 10;
       avs->argv = realloc(avs->argv, sizeof(avs->argv[0])*avs->argmax);
       if (avs->argv == NULL) {
	  fprintf(stderr, "Out of memory\n");
	  exit(1);
       }
   }

   avs->argv[avs->argc++] = val;
   avs->argv[avs->argc] = NULL;
}

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

    p = line + sizeof("/dev/") - 1;
    if (logout(p)) logwtmp(p, "", "");
#ifdef PARANOID_TTYS
    /*
     * dholland 16-Aug-96 chmod the tty when not in use
     * This will make it harder to attach unwanted stuff to it
     * (which is a security risk) but will break some programs.
     */
    chmod(line, 0600);
#else
    chmod(line, 0666);
#endif
    chown(line, 0, 0);
    *p = 'p';
    chmod(line, 0666);
    chown(line, 0, 0);
    shutdown(net, 2);
    exit(1);
}