/*
 * Copyright (c) 1995 Ugen J.S.Antsilevich
 *
 * Redistribution and use in source forms, with and without modification,
 * are permitted provided that this entire comment appears intact.
 *
 * Redistribution in binary form may occur without any restrictions.
 * Obviously, it would be nice if you gave credit where credit is due
 * but requiring it would be too onerous.
 *
 * This software is provided ``AS IS'' without any warranties of any kind.
 *
 * Snoop stuff.
 */

#include "snp.h"

#if (defined NSNP) && (NSNP > 0)

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/ioctl.h>
#include <sys/ioctl_compat.h>		/* Oooh..We need O/NTTYDISC	*/
#include <sys/proc.h>
#define TTYDEFCHARS
#include <sys/tty.h>
#undef  TTYDEFCHARS
#include <sys/file.h>
#include <sys/conf.h>
#include <sys/uio.h>
#include <sys/kernel.h>
#include <sys/malloc.h>

#include <sys/snoop.h>



#ifdef ST_PTY
/*
 * This should be same as in "kern/tty_pty.c"
 */
#include "pty.h"

#if NPTY == 1
#undef NPTY
#define NPTY 	32
#endif

extern struct tty	pt_tty[];
#endif	/* ST_PTY */


#ifdef ST_SIO
/*
 * This should be same as "i386/isa/sio.c"
 */
#include "sio.h"

extern struct tty	sio_tty[];
#endif /* ST_SIO */


#ifdef ST_VTY
/*
 * This should match "i386/isa/sc.c"
 */
 
#if !defined(MAXCONS) 
#define MAXCONS 16 
#endif

extern struct tty	sccons[];
#endif 	/* ST_VTY */


/*
 * This is local structure to hold
 * data for all tty arrays we serve.
 */
typedef	struct tty	tty_arr[];
struct tty_tab {
	int		lt_max;
	tty_arr		*lt_tab;
};

static struct	tty_tab	tty_tabs[]={
#ifdef ST_PTY
	{ NPTY	,	&pt_tty    },
#else
	{ -1	,	NULL	  },
#endif
#ifdef ST_VTY
	{ MAXCONS,	&sccons    },
#else
	{ -1	,	NULL	  },
#endif
#ifdef	ST_SIO
	{ NSIO	,	&sio_tty	  }
#else
	{ -1	,	NULL	  }
#endif
};


#ifndef MIN
#define MIN(a,b) (((a)<(b))?(a):(b))
#endif


static struct snoop snoopsw[NSNP];

int
snpread(dev, uio, flag)
	dev_t dev;
	struct uio *uio;
	int flag;
{
	int unit = minor(dev),s;
	struct snoop *snp = &snoopsw[unit];
	int len,n,nblen,error = 0;
	caddr_t	from;
	char	*nbuf;
	
#ifdef DIAGNOSTIC
	if ((snp->snp_len+snp->snp_base)>snp->snp_blen)
		panic("snoop buffer error");
#endif
	if (snp->snp_unit==-1)
		return (EIO);

        snp->snp_flags &= ~SNOOP_RWAIT;

	do {
	 	if (snp->snp_len == 0) {
			if (snp->snp_flags & SNOOP_NBIO) {
				return EWOULDBLOCK;
			}
			snp->snp_flags|=SNOOP_RWAIT;
			tsleep((caddr_t)snp,(PZERO+1)|PCATCH,"snoopread",0);
		}
	} while (snp->snp_len == 0);

	n = uio->uio_resid;

	while  (snp->snp_len > 0 && uio->uio_resid > 0 && error == 0) {
		len = MIN(uio->uio_resid,snp->snp_len);
		from = (caddr_t)(snp->snp_buf+snp->snp_base);
		if (len == 0)
			break;

		error = uiomove(from,len,uio);
		snp->snp_base+=len;
		snp->snp_len-=len;
	}
	if (n)
		snp->snp_flags &= ~SNOOP_OFLOW;

	s=spltty();
	nblen=snp->snp_blen;
	if (((nblen/2)>=SNOOP_MINLEN) && (nblen/2)>=snp->snp_len) {
		while (((nblen/2)>=snp->snp_len) && ((nblen/2)>=SNOOP_MINLEN))
			nblen=nblen/2;
		if (nbuf=malloc(nblen,M_TTYS,M_NOWAIT)) {
			bcopy(snp->snp_buf+snp->snp_base,nbuf,snp->snp_len);
			free(snp->snp_buf,M_TTYS);
			snp->snp_buf=nbuf;
			snp->snp_blen=nblen;
			snp->snp_base=0;
		}
	}
	splx(s);

	return error;
}


int
snpin(snp,buf,n)
struct snoop	*snp;
char		*buf;
int		n;
{
	int		s_free,s_tail;
	int		s,len,nblen;
	caddr_t		from,to;
	char		*nbuf;
	struct tty_tab	*l_tty;
	struct tty	*tp;


	if (n == 0) 
		return 0;

#ifdef DIAGNOSTIC
	if (n < 0)
		panic("bad snoop char count");
#endif
	if (snp->snp_flags&SNOOP_OFLOW) {
	printf("Snoop: buffer overflow \n");
	/*
	 * On overflow we just repeat the standart 
	 * close procedure...yes , this is waste of space but..
 	 * Then next read from device will fail if one would
	 * recall he is snooping and retry...
	 */
	snp->snp_flags &= ~SNOOP_OPEN;
	snp->snp_base = 0;
	snp->snp_len = 0;
	snp->snp_blen=0;
	free(snp->snp_buf,M_TTYS);

	/*
	 * If line disc. changed we do not touch
	 * this pointer,SLIP/PPP will change it anyway.
	 */

	if (snp->snp_unit==-1) 
		goto oflow_notty;

	l_tty=&(tty_tabs[snp->snp_type]);
	tp=&((*l_tty->lt_tab)[snp->snp_unit]);

	if (tp->t_sc == snp && (tp->t_state&TS_SNOOP) &&
		(tp->t_line == OTTYDISC || tp->t_line == NTTYDISC)) {
		tp->t_sc = NULL;
		tp->t_state &=~TS_SNOOP;
	};
	snp->snp_unit=-1;

oflow_notty:
	selwakeup(&snp->snp_sel);
        snp->snp_sel.si_pid = 0;

	return (0);
}

	s_free = snp->snp_blen - ( snp->snp_len + snp->snp_base );
	s_tail = snp->snp_blen - snp->snp_len;


	if (n > s_free) {
		s=spltty();
		nblen=snp->snp_blen;
		while ((n > s_free) && ((nblen*2)<=SNOOP_MAXLEN)) {
			nblen=snp->snp_blen*2;
			s_free = nblen - ( snp->snp_len + snp->snp_base );
		}
		if ((n<=s_free) && (nbuf=malloc(nblen,M_TTYS,M_NOWAIT))) {
			bcopy(snp->snp_buf+snp->snp_base,nbuf,snp->snp_len);
			free(snp->snp_buf,M_TTYS);
			snp->snp_buf=nbuf;
			snp->snp_blen=nblen;
			snp->snp_base=0;
		} else {
			snp->snp_flags|=SNOOP_OFLOW;
			if (snp->snp_flags & SNOOP_RWAIT) {
                		snp->snp_flags &= ~SNOOP_RWAIT;
                		wakeup((caddr_t)snp);
        		}
			splx(s);
			return 0;
		}
		splx(s);
	}

	if (n > s_tail) {
		from=(caddr_t)(snp->snp_buf+snp->snp_base);
		to=(caddr_t)(snp->snp_buf);
		len=snp->snp_len;
		bcopy(from,to,len);
		snp->snp_base=0;
	}


	to=(caddr_t)(snp->snp_buf+snp->snp_base+snp->snp_len);
	bcopy(buf,to,n);
	snp->snp_len+=n;

	if (snp->snp_flags & SNOOP_RWAIT) {
               	snp->snp_flags &= ~SNOOP_RWAIT;
        	wakeup((caddr_t)snp);
        }

	selwakeup(&snp->snp_sel);
        snp->snp_sel.si_pid = 0;

	return n;
}

int
snpopen(dev, flag, mode, p)
	dev_t	dev;
	int	flag, mode;
	struct proc *p;
{
	struct snoop *snp;
	register int	unit, error;

	if (error = suser(p->p_ucred, &p->p_acflag))
		return (error);

	if ((unit = minor(dev)) >= NSNP)
		return (ENXIO);
	snp = &snoopsw[unit];
	if (snp->snp_flags & SNOOP_OPEN)
		return (ENXIO);
	snp->snp_flags |= SNOOP_OPEN;

	snp->snp_buf=malloc(SNOOP_MINLEN,M_TTYS,M_WAITOK);
	snp->snp_blen=SNOOP_MINLEN;
	snp->snp_base=0;
	snp->snp_len=0;

	/*
	 * unit == -1  is for inactive snoop
	 * devices.
	 */
	snp->snp_unit=-1;

	return (0);
}

int
snpclose(dev, flag)
	dev_t	dev;
	int	flag;
{
	register int	unit = minor(dev);
	struct snoop *snp = &snoopsw[unit];
	struct tty	*tp;
	struct tty_tab	*l_tty;

	snp->snp_flags &= ~SNOOP_OPEN;
	snp->snp_base = 0;
	snp->snp_len = 0;
	snp->snp_blen=0;
	free(snp->snp_buf,M_TTYS);

	/*
	 * If line disc. changed we do not touch
	 * this pointer,SLIP/PPP will change it anyway.
	 */

	if (snp->snp_unit==-1) 
		goto close_notty;

	l_tty=&tty_tabs[snp->snp_type];
	tp=&((*l_tty->lt_tab)[snp->snp_unit]);

	if (tp->t_sc == snp && (tp->t_state&TS_SNOOP) &&
		(tp->t_line == OTTYDISC || tp->t_line == NTTYDISC)) {
		tp->t_sc = NULL;
		tp->t_state &=~TS_SNOOP;
	};
	snp->snp_unit=-1;

close_notty:
	selwakeup(&snp->snp_sel);
        snp->snp_sel.si_pid = 0;

	return (0);
}




int
snpioctl(dev, cmd, data, flag)
	dev_t		dev;
	int		cmd;
	caddr_t		data;
	int		flag;
{
	int		unit = minor(dev),s;
	int		tunit,ttype;
	struct snoop 	*snp = &snoopsw[unit];
	struct tty   	*tp,*tpo;
	struct tty_tab	*l_tty,*l_otty;

	switch (cmd) {
	case SNPSTTY:
		tunit=((struct snptty *)data)->st_unit;
		ttype=((struct snptty *)data)->st_type;

		if (ttype < 0 || ttype > ST_MAXTYPE)
			return (EINVAL);

		l_tty = &tty_tabs[ttype];
		if (l_tty->lt_tab == NULL)
			return (EINVAL);

		if (tunit < 0 || tunit >= l_tty->lt_max)
			return (EINVAL);

		tp=&((*l_tty->lt_tab)[tunit]);

		if (tp->t_sc!=(caddr_t)snp && (tp->t_state&TS_SNOOP))
			return (EBUSY);

		if (tp->t_line!=OTTYDISC && tp->t_line!=NTTYDISC)
			return (EBUSY);

		s=spltty();
		if (snp->snp_unit != -1) {
			l_otty=&tty_tabs[snp->snp_type];
			tpo=&((*l_otty->lt_tab)[snp->snp_unit]);
			tpo->t_state &=~TS_SNOOP;
		}

		tp->t_sc=(caddr_t)snp;
		tp->t_state |= TS_SNOOP;
		snp->snp_unit = tunit;
		splx(s);

		break;
	case SNPGTTY:
		((struct snptty *)data)->st_unit = snp->snp_unit;
		((struct snptty *)data)->st_type = snp->snp_type;
		break;
		
	case FIONBIO:
		if (*(int *)data)
			snp->snp_flags |= SNOOP_NBIO;
		else
			snp->snp_flags &= ~SNOOP_NBIO;
		break;
	case FIOASYNC:
		if (*(int *)data)
			snp->snp_flags |= SNOOP_ASYNC;
		else
			snp->snp_flags &= ~SNOOP_ASYNC;
		break;
	case FIONREAD:
		s = spltty();
		if (snp->snp_unit!=-1)
			*(int *)data = snp->snp_len;
		else	
			*(int *)data = 0;
		splx(s);
		break;
	default:
		return (ENOTTY);
	}
	return (0);
}


int
snpselect(dev, rw, p)
	dev_t		dev;
	int		rw;
	struct proc	*p;
{
	int		unit = minor(dev), s;
	struct snoop 	*snp = &snoopsw[unit];

        if (rw != FREAD) {
                return 0;
	}

	if (snp->snp_len > 0) {
                return 1;
        }

	selrecord(p, &snp->snp_sel);
	return 0;
}

#endif