/* pty_unicos.c - routines to allocate ptys - for CRAY UNICOS 5.1 and 6.0 */

/*

Original by: Don Libes, NIST, 2/6/90
Hacked for Unicos 5.1 by: Frank Terhaar-Yonkers, US EPA,  1/10/91
Hacked for Unicos 6.0 by: Pete TerMaat, pete@willow.cray.com, 3/27/91

Design and implementation of this program was paid for by U.S. tax
dollars.  Therefore it is public domain.  However, the author and NIST
would appreciate credit if this program or parts of it are used.

*/

#include "expect_cf.h"
#include <stdio.h>
#include <signal.h>

#if defined(SIGCLD) && !defined(SIGCHLD)
#define SIGCHLD SIGCLD
#endif

#ifdef HAVE_UNISTD_H
#include <unistd.h>
#else
extern int fork(), execl(), wait();
#endif
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <sys/file.h>
#ifdef HAVE_SYS_FCNTL_H
#  include <sys/fcntl.h>
#else
#  include <fcntl.h>
#endif
/*#if CRAY>=60*/
#if defined(HAVE_TERMIOS)
# include <sys/termios.h>
#else
# include <sys/termio.h>
/*#endif /* 60 */*/
#endif /* defined(HAVE_TERMIOS) */
#if CRAY>=70 && defined(_CRAY2)
#include <sys/session.h>
#endif /* 70 */
#include <sys/pty.h>
#include <pwd.h>
#include <utmp.h>
#include <signal.h>
#include "exp_tty_in.h"
#include "exp_rename.h"

#ifdef HAVE_SYSCONF_H
#include <sys/sysconfig.h>
#endif

void debuglog();

#ifndef TRUE
#define TRUE 1
#define FALSE 0
#endif

#ifndef MAXHOSTNAMELEN
#define MAXHOSTNAMELEN 64
#endif /* MAXHOSTNAMELEN */

static char	linep[] = "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0";
static char	linet[] = "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0";
static int	lowpty;
static int	highpty;
static int	realuid;
static int	realgid;
static int 	*ptys;
static char myname[32];
static char hostname[MAXHOSTNAMELEN];
char *exp_pty_slave_name;
char *exp_pty_error;

static void
pty_stty(s,name)
char *s;		/* args to stty */
char *name;		/* name of pty */
{
#define MAX_ARGLIST 10240
	char buf[MAX_ARGLIST];	/* overkill is easier */
	RETSIGTYPE (*old)();	/* save old sigalarm handler */

#ifdef STTY_READS_STDOUT
	sprintf(buf,"/bin/stty %s > %s",s,name);
#else
	sprintf(buf,"/bin/stty %s < %s",s,name);
#endif
	old = signal(SIGCHLD, SIG_DFL);
	system(buf);
	signal(SIGCHLD, old);	/* restore signal handler */
}

int exp_dev_tty;	/* file descriptor to /dev/tty or -1 if none */
static int knew_dev_tty;/* true if we had our hands on /dev/tty at any time */

#ifdef TIOCGWINSZ
static struct winsize winsize = {0, 0};
#endif
#if defined(TIOCGSIZE) && !defined(TIOCGWINSZ)
static struct ttysize winsize = {0, 0};
#endif

/*struct	termio exp_tty_original;*/
exp_tty exp_tty_original;

#define GET_TTYTYPE	0
#define SET_TTYTYPE	1
static void
ttytype(request,fd,ttycopy,ttyinit,s)
int request;
int fd;
		/* following are used only if request == SET_TTYTYPE */
int ttycopy;	/* true/false, copy from /dev/tty */
int ttyinit;	/* if true, initialize to sane state */
char *s;	/* stty args, used only if request == SET_TTYTYPE */
{
	if (request == GET_TTYTYPE) {
		if (-1 == ioctl(fd, TCGETA, (char *)&exp_tty_original)) {
			knew_dev_tty = FALSE;
			exp_dev_tty = -1;
		}
#ifdef TIOCGWINSZ
		ioctl(fd,TIOCGWINSZ,&winsize);
#endif
#if defined(TIOCGSIZE) && !defined(TIOCGWINSZ)
		ioctl(fd,TIOCGSIZE,&winsize);
#endif
	} else {	/* type == SET_TTYTYPE */
		if (ttycopy && knew_dev_tty) {
			(void) ioctl(fd, TCSETA, (char *)&exp_tty_current);
#ifdef TIOCSWINSZ
			ioctl(fd,TIOCSWINSZ,&winsize);
#endif
#if defined(TIOCSSIZE) && !defined(TIOCSWINSZ)
			ioctl(fd,TIOCGSIZE,&winsize);
#endif
		}

		if (ttyinit) {
			/* overlay parms originally supplied by Makefile */
			pty_stty(DFLT_STTY,linet);
		}

		/* lastly, give user chance to override any terminal parms */
		if (s) {
			pty_stty(s,linet);
		}
	}
}

void
exp_init_pty()
{
	int npty;
	char *myline;

	lowpty=0;
#ifdef _SC_CRAY_NPTY
	highpty=sysconf(_SC_CRAY_NPTY);
#else
	highpty=128;
#endif /* _SC_CRAY_NPTY */

	ptys = (int *) malloc(sizeof(int)*(highpty+1));
	if (ptys == NULL) {
		fprintf(stderr,"exp_init_pty:  couldn't allocate pty array\n");
		exit(1);
	}
	for (npty = lowpty;npty <= highpty;npty++)
		ptys[npty] = 0;

 	realuid=getuid();	/* get REAL uid */
 	realgid=getgid();	/* get REAL uid */

	exp_dev_tty = open("/dev/tty",O_RDWR);
	knew_dev_tty = (exp_dev_tty != -1);
	if (knew_dev_tty) ttytype(GET_TTYTYPE,exp_dev_tty,0,0,(char *)0);

	/*
	 * Acquire (as root) current user name and host.
	 */
	(void) cuserid(myname);
	(void) gethostname(hostname,sizeof(hostname));

	/*
	 * Set the real and effective userids to root using 'setuid'.  Then
	 * set the real and effective userids to the actual user using
	 * 'setreuid'.  This allows using 'seteuid' to go back and forth from
	 * root and the actual userid.  Don't ask me why it works.
	 */
	setuid(0);
	setreuid(realuid,realuid);
}

/* returns fd of master end of pseudotty */
int
getptymaster()
{
	struct stat sb;
	int master;
	int npty;

	exp_pty_error = 0;

	debuglog("getptymaster:  lowpty=%d  highpty=%d\n",lowpty,highpty);
	for (npty = lowpty; npty <= highpty; npty++) {
		if (seteuid(0) == -1) {		/* we need to be root! */
			debuglog("getptymaster:  seteuid root errno=%d\n",
				errno);
		}
		(void) sprintf(linep, "/dev/pty/%03d", npty);
		master = open(linep, O_RDWR);

		if (master < 0) {
			debuglog("getptymaster:  open linep=%s errno=%d\n",
				linep,errno);
			continue;
		}

		(void) sprintf(linet, "/dev/ttyp%03d", npty);
		if(stat(linet, &sb) < 0) {
			debuglog("getptymaster:  stat linet=%s errno=%d\n",
				linet,errno);
			(void) close(master);
			continue;
		}
		if (sb.st_uid || sb.st_gid || sb.st_mode != 0600) {
                        if (chown(linet, realuid, realgid) == -1) {
				debuglog("getptymaster:  chown linet=%s errno=%d\n",
					linet,errno);
			}
                        if (chmod(linet, 0600) == -1) {
				debuglog("getptymaster:  chmod linet=%s errno=%d\n",
					linet,errno);
			}
                        (void)close(master);
                        master = open(linep, 2);
                        if (master < 0) {
				debuglog("getptymaster:  reopen linep=%s errno=%d\n",
					linep,errno);
                                continue;
			}
                }
		if (seteuid(realuid) == -1) {	/* back to who we are! */
			debuglog("getptymaster:  seteuid user errno=%d\n",
				errno);
		}
		if (access(linet, R_OK|W_OK) != 0) {
			debuglog("getptymaster:  access linet=%s errno=%d\n",
				linet,errno);
			(void) close(master);
			continue;
		}
		debuglog("getptymaster:  allocated %s\n",linet);
		ptys[npty] = -1;
		exp_pty_slave_name = linet;
		return(master);
	}
	if (seteuid(realuid) == -1) {		/* back to who we are! */
		debuglog("getptymaster:  seteuid user errno=%d\n",errno);
	}
	return(-1);
}

/* see comment in pty_termios.c */
/*ARGSUSED*/
void
exp_slave_control(master,control)
int master;
int control;
{
}

int
getptyslave(ttycopy,ttyinit,stty_args)
int ttycopy;
int ttyinit;
char *stty_args;
{
	int slave;

	if (0 > (slave = open(linet, O_RDWR))) {
		debuglog("getptyslave:  open linet=%s errno=%d\n",linet,errno);
		return(-1);
	}

	/* sanity check - if slave not 0, skip rest of this and return */
	/* to what will later be detected as an error in caller */
	if (0 != slave) {
		debuglog("getptyslave:  slave fd not 0\n");
		 return(slave);
	}

	if (0 == slave) {
		/* if opened in a new process, slave will be 0 (and */
		/* ultimately, 1 and 2 as well) */

		/* duplicate 0 onto 1 and 2 to prepare for stty */
		fcntl(0,F_DUPFD,1);
		fcntl(0,F_DUPFD,2);
	}

	ttytype(SET_TTYTYPE,slave,ttycopy,ttyinit,stty_args);
	return(slave);
}

setptyutmp()
{
	struct utmp utmp;

	if (seteuid(0) == -1) {		/* Need to be root */
		debuglog("setptyutmp:  setuid root errno=%d\n",errno);
		return(-1);
	}
	(void) time(&utmp.ut_time);
	utmp.ut_type = USER_PROCESS;
	utmp.ut_pid = getpid();
	strncpy(utmp.ut_user,myname,sizeof(utmp.ut_user));
	strncpy(utmp.ut_host,hostname,sizeof(utmp.ut_host));
	strncpy(utmp.ut_line,linet+5,sizeof(utmp.ut_line));
	strncpy(utmp.ut_id,linet+8,sizeof(utmp.ut_id));
	if (pututline(&utmp) == NULL) {
		debuglog("setptyutmp:  pututline failed\n");
	}
	endutent();
	if (seteuid(realuid) == -1)
		debuglog("setptyutmp:  seteuid user errno=%d\n",errno);
	return(0);
}

setptypid(pid)
int pid;
{
        int npty;

        for (npty = lowpty; npty <= highpty; npty++) {
                if (ptys[npty] < 0) {
                        debuglog("setptypid:  ttyp%03d pid=%d\n",npty,pid);
                        ptys[npty] = pid;
                        break;
                }
        }
}

ttyp_reset()
{
        int npty;

        if (seteuid(0) == -1) {		/* we need to be root! */
                debuglog("ttyp_reset:  seteuid root errno=%d\n",errno);
        }
        for (npty = lowpty; npty <= highpty; npty++) {
                if (ptys[npty] <= 0)
                        continue;

                (void) sprintf(linet, "/dev/ttyp%03d", npty);
                debuglog("ttyp_reset:  resetting %s, killing %d\n",
			linet,ptys[npty]);
                if (chown(linet,0,0) == -1) {
                        debuglog("ttyp_reset: chown %s errno=%d\n",linet,errno);
                }
                if (chmod(linet, 0666) == -1) {
                        debuglog("ttyp_reset: chmod %s errno=%d\n",linet,errno);
                }
                resetptyutmp();
                if (kill(ptys[npty],SIGKILL) == -1) {
                        debuglog("ttyp_reset:  kill pid=%d errno=%d\n",
                                ptys[npty],errno);
                }
        }
        if (seteuid(realuid) == -1) {   /* Back to who we really are */
                debuglog("ttyp_reset:  seteuid user errno=%d\n",errno);
        }
}

resetptyutmp()
{
        struct utmp utmp;

        (void) setutent ();
        /* set up entry to search for */
        (void) strncpy(utmp.ut_id, linet + strlen(linet) - 4,
                 sizeof (utmp.ut_id));
        utmp.ut_type = USER_PROCESS;

        /* position to entry in utmp file */
        if(getutid(&utmp) == NULL) {
                debuglog("resetptyutmp:  no utmp entry for %s\n",linet);
                return(-1);     /* no utmp entry for this line ??? */
        }

        /* set up the new entry */
        strncpy(utmp.ut_name,"",sizeof(utmp.ut_name));
        strncpy(utmp.ut_host,"",sizeof(utmp.ut_host));
        time(&utmp.ut_time);
        utmp.ut_type = DEAD_PROCESS;
        utmp.ut_exit.e_exit = 0;

        /* write out the entry */
        pututline(&utmp);

        /* close the file */
        (void) endutent();
        return(0);
}