usr/src/uts/common/io/ldterm.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 * Copyright (c) 2014, Joyent, Inc.  All rights reserved.
 * Copyright 2018 OmniOS Community Edition (OmniOSce) Association.
 */

/* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
/* All Rights Reserved					*/

/*
 * University Copyright- Copyright (c) 1982, 1986, 1988
 * The Regents of the University of California
 * All Rights Reserved
 *
 * University Acknowledgment- Portions of this document are derived from
 * software developed by the University of California, Berkeley, and its
 * contributors.
 */

/*
 * Standard Streams Terminal Line Discipline module.
 */

#include <sys/param.h>
#include <sys/types.h>
#include <sys/termio.h>
#include <sys/stream.h>
#include <sys/conf.h>
#include <sys/stropts.h>
#include <sys/strsubr.h>
#include <sys/strsun.h>
#include <sys/strtty.h>
#include <sys/signal.h>
#include <sys/file.h>
#include <sys/errno.h>
#include <sys/debug.h>
#include <sys/cmn_err.h>
#include <sys/euc.h>
#include <sys/eucioctl.h>
#include <sys/csiioctl.h>
#include <sys/ptms.h>
#include <sys/ldterm.h>
#include <sys/cred.h>
#include <sys/ddi.h>
#include <sys/sunddi.h>
#include <sys/kmem.h>
#include <sys/modctl.h>

/* Time limit when draining during a close(9E) invoked by exit(2) */
/* Can be set to zero to emulate the old, broken behavior */
int ldterm_drain_limit = 15000000;

/*
 * Character types.
 */
#define	ORDINARY	0
#define	CONTROL		1
#define	BACKSPACE	2
#define	NEWLINE		3
#define	TAB		4
#define	VTAB		5
#define	RETURN		6

/*
 * The following for EUC handling:
 */
#define	T_SS2		7
#define	T_SS3		8

/*
 * Table indicating character classes to tty driver.  In particular,
 * if the class is ORDINARY, then the character needs no special
 * processing on output.
 *
 * Characters in the C1 set are all considered CONTROL; this will
 * work with terminals that properly use the ANSI/ISO extensions,
 * but might cause distress with terminals that put graphics in
 * the range 0200-0237.  On the other hand, characters in that
 * range cause even greater distress to other UNIX terminal drivers....
 */

static char typetab[256] = {
/* 000 */	CONTROL,	CONTROL,	CONTROL,	CONTROL,
/* 004 */	CONTROL,	CONTROL,	CONTROL,	CONTROL,
/* 010 */	BACKSPACE,	TAB,		NEWLINE,	CONTROL,
/* 014 */	VTAB,		RETURN,		CONTROL,	CONTROL,
/* 020 */	CONTROL,	CONTROL,	CONTROL,	CONTROL,
/* 024 */	CONTROL,	CONTROL,	CONTROL,	CONTROL,
/* 030 */	CONTROL,	CONTROL,	CONTROL,	CONTROL,
/* 034 */	CONTROL,	CONTROL,	CONTROL,	CONTROL,
/* 040 */	ORDINARY,	ORDINARY,	ORDINARY,	ORDINARY,
/* 044 */	ORDINARY,	ORDINARY,	ORDINARY,	ORDINARY,
/* 050 */	ORDINARY,	ORDINARY,	ORDINARY,	ORDINARY,
/* 054 */	ORDINARY,	ORDINARY,	ORDINARY,	ORDINARY,
/* 060 */	ORDINARY,	ORDINARY,	ORDINARY,	ORDINARY,
/* 064 */	ORDINARY,	ORDINARY,	ORDINARY,	ORDINARY,
/* 070 */	ORDINARY,	ORDINARY,	ORDINARY,	ORDINARY,
/* 074 */	ORDINARY,	ORDINARY,	ORDINARY,	ORDINARY,
/* 100 */	ORDINARY,	ORDINARY,	ORDINARY,	ORDINARY,
/* 104 */	ORDINARY,	ORDINARY,	ORDINARY,	ORDINARY,
/* 110 */	ORDINARY,	ORDINARY,	ORDINARY,	ORDINARY,
/* 114 */	ORDINARY,	ORDINARY,	ORDINARY,	ORDINARY,
/* 120 */	ORDINARY,	ORDINARY,	ORDINARY,	ORDINARY,
/* 124 */	ORDINARY,	ORDINARY,	ORDINARY,	ORDINARY,
/* 130 */	ORDINARY,	ORDINARY,	ORDINARY,	ORDINARY,
/* 134 */	ORDINARY,	ORDINARY,	ORDINARY,	ORDINARY,
/* 140 */	ORDINARY,	ORDINARY,	ORDINARY,	ORDINARY,
/* 144 */	ORDINARY,	ORDINARY,	ORDINARY,	ORDINARY,
/* 150 */	ORDINARY,	ORDINARY,	ORDINARY,	ORDINARY,
/* 154 */	ORDINARY,	ORDINARY,	ORDINARY,	ORDINARY,
/* 160 */	ORDINARY,	ORDINARY,	ORDINARY,	ORDINARY,
/* 164 */	ORDINARY,	ORDINARY,	ORDINARY,	ORDINARY,
/* 170 */	ORDINARY,	ORDINARY,	ORDINARY,	ORDINARY,
/* 174 */	ORDINARY,	ORDINARY,	ORDINARY,	CONTROL,
/* 200 */	CONTROL,	CONTROL,	CONTROL,	CONTROL,
/* 204 */	CONTROL,	CONTROL,	T_SS2,		T_SS3,
/* 210 */	CONTROL,	CONTROL,	CONTROL,	CONTROL,
/* 214 */	CONTROL,	CONTROL,	CONTROL,	CONTROL,
/* 220 */	CONTROL,	CONTROL,	CONTROL,	CONTROL,
/* 224 */	CONTROL,	CONTROL,	CONTROL,	CONTROL,
/* 230 */	CONTROL,	CONTROL,	CONTROL,	CONTROL,
/* 234 */	CONTROL,	CONTROL,	CONTROL,	CONTROL,
/* 240 */	ORDINARY,	ORDINARY,	ORDINARY,	ORDINARY,
/* 244 */	ORDINARY,	ORDINARY,	ORDINARY,	ORDINARY,
/* 250 */	ORDINARY,	ORDINARY,	ORDINARY,	ORDINARY,
/* 254 */	ORDINARY,	ORDINARY,	ORDINARY,	ORDINARY,
/* 260 */	ORDINARY,	ORDINARY,	ORDINARY,	ORDINARY,
/* 264 */	ORDINARY,	ORDINARY,	ORDINARY,	ORDINARY,
/* 270 */	ORDINARY,	ORDINARY,	ORDINARY,	ORDINARY,
/* 274 */	ORDINARY,	ORDINARY,	ORDINARY,	ORDINARY,
/* 300 */	ORDINARY,	ORDINARY,	ORDINARY,	ORDINARY,
/* 304 */	ORDINARY,	ORDINARY,	ORDINARY,	ORDINARY,
/* 310 */	ORDINARY,	ORDINARY,	ORDINARY,	ORDINARY,
/* 314 */	ORDINARY,	ORDINARY,	ORDINARY,	ORDINARY,
/* 320 */	ORDINARY,	ORDINARY,	ORDINARY,	ORDINARY,
/* 324 */	ORDINARY,	ORDINARY,	ORDINARY,	ORDINARY,
/* 330 */	ORDINARY,	ORDINARY,	ORDINARY,	ORDINARY,
/* 334 */	ORDINARY,	ORDINARY,	ORDINARY,	ORDINARY,
/* 340 */	ORDINARY,	ORDINARY,	ORDINARY,	ORDINARY,
/* 344 */	ORDINARY,	ORDINARY,	ORDINARY,	ORDINARY,
/* 350 */	ORDINARY,	ORDINARY,	ORDINARY,	ORDINARY,
/* 354 */	ORDINARY,	ORDINARY,	ORDINARY,	ORDINARY,
/* 360 */	ORDINARY,	ORDINARY,	ORDINARY,	ORDINARY,
/* 364 */	ORDINARY,	ORDINARY,	ORDINARY,	ORDINARY,
/* 370 */	ORDINARY,	ORDINARY,	ORDINARY,	ORDINARY,
/*
 * WARNING:  For EUC, 0xFF must be an ordinary character.  It is used with
 * single-byte EUC in some of the "ISO Latin Alphabet" codesets, and occupies
 * a screen position; in those ISO sets where that position isn't used, it
 * shouldn't make any difference.
 */
/* 374 */	ORDINARY,	ORDINARY,	ORDINARY,	ORDINARY,
};

/*
 * Translation table for output without OLCUC.  All ORDINARY-class characters
 * translate to themselves.  All other characters have a zero in the table,
 * which stops the copying.
 */
static unsigned char notrantab[256] = {
/* 000 */	0,	0,	0,	0,	0,	0,	0,	0,
/* 010 */	0,	0,	0,	0,	0,	0,	0,	0,
/* 020 */	0,	0,	0,	0,	0,	0,	0,	0,
/* 030 */	0,	0,	0,	0,	0,	0,	0,	0,
/* 040 */	' ',	'!',	'"',	'#',	'$',	'%',	'&',	'\'',
/* 050 */	'(',	')',	'*',	'+',	',',	'-',	'.',	'/',
/* 060 */	'0',	'1',	'2',	'3',	'4',	'5',	'6',	'7',
/* 070 */	'8',	'9',	':',	';',	'<',	'=',	'>',	'?',
/* 100 */	'@',	'A',	'B',	'C',	'D',	'E',	'F',	'G',
/* 110 */	'H',	'I',	'J',	'K',	'L',	'M',	'N',	'O',
/* 120 */	'P',	'Q',	'R',	'S',	'T',	'U',	'V',	'W',
/* 130 */	'X',	'Y',	'Z',	'[',	'\\',	']',	'^',	'_',
/* 140 */	'`',	'a',	'b',	'c',	'd',	'e',	'f',	'g',
/* 150 */	'h',	'i',	'j',	'k',	'l',	'm',	'n',	'o',
/* 160 */	'p',	'q',	'r',	's',	't',	'u',	'v',	'w',
/* 170 */	'x',	'y',	'z',	'{',	'|',	'}',	'~',	0,
/* 200 */	0,	0,	0,	0,	0,	0,	0,	0,
/* 210 */	0,	0,	0,	0,	0,	0,	0,	0,
/* 220 */	0,	0,	0,	0,	0,	0,	0,	0,
/* 230 */	0,	0,	0,	0,	0,	0,	0,	0,
/* 240 */	0240,	0241,	0242,	0243,	0244,	0245,	0246,	0247,
/* 250 */	0250,	0251,	0252,	0253,	0254,	0255,	0256,	0257,
/* 260 */	0260,	0261,	0262,	0263,	0264,	0265,	0266,	0267,
/* 270 */	0270,	0271,	0272,	0273,	0274,	0275,	0276,	0277,
/* 300 */	0300,	0301,	0302,	0303,	0304,	0305,	0306,	0307,
/* 310 */	0310,	0311,	0312,	0313,	0314,	0315,	0316,	0317,
/* 320 */	0320,	0321,	0322,	0323,	0324,	0325,	0326,	0327,
/* 330 */	0330,	0331,	0332,	0333,	0334,	0335,	0336,	0337,
/* 340 */	0340,	0341,	0342,	0343,	0344,	0345,	0346,	0347,
/* 350 */	0350,	0351,	0352,	0353,	0354,	0355,	0356,	0357,
/* 360 */	0360,	0361,	0362,	0363,	0364,	0365,	0366,	0367,
/*
 * WARNING: as for above ISO sets, \377 may be used.  Translate it to
 * itself.
 */
/* 370 */	0370,	0371,	0372,	0373,	0374,	0375,	0376,	0377,
};

/*
 * Translation table for output with OLCUC.  All ORDINARY-class characters
 * translate to themselves, except for lower-case letters which translate
 * to their upper-case equivalents.  All other characters have a zero in
 * the table, which stops the copying.
 */
static unsigned char lcuctab[256] = {
/* 000 */	0,	0,	0,	0,	0,	0,	0,	0,
/* 010 */	0,	0,	0,	0,	0,	0,	0,	0,
/* 020 */	0,	0,	0,	0,	0,	0,	0,	0,
/* 030 */	0,	0,	0,	0,	0,	0,	0,	0,
/* 040 */	' ',	'!',	'"',	'#',	'$',	'%',	'&',	'\'',
/* 050 */	'(',	')',	'*',	'+',	',',	'-',	'.',	'/',
/* 060 */	'0',	'1',	'2',	'3',	'4',	'5',	'6',	'7',
/* 070 */	'8',	'9',	':',	';',	'<',	'=',	'>',	'?',
/* 100 */	'@',	'A',	'B',	'C',	'D',	'E',	'F',	'G',
/* 110 */	'H',	'I',	'J',	'K',	'L',	'M',	'N',	'O',
/* 120 */	'P',	'Q',	'R',	'S',	'T',	'U',	'V',	'W',
/* 130 */	'X',	'Y',	'Z',	'[',	'\\',	']',	'^',	'_',
/* 140 */	'`',	'A',	'B',	'C',	'D',	'E',	'F',	'G',
/* 150 */	'H',	'I',	'J',	'K',	'L',	'M',	'N',	'O',
/* 160 */	'P',	'Q',	'R',	'S',	'T',	'U',	'V',	'W',
/* 170 */	'X',	'Y',	'Z',	'{',	'|',	'}',	'~',	0,
/* 200 */	0,	0,	0,	0,	0,	0,	0,	0,
/* 210 */	0,	0,	0,	0,	0,	0,	0,	0,
/* 220 */	0,	0,	0,	0,	0,	0,	0,	0,
/* 230 */	0,	0,	0,	0,	0,	0,	0,	0,
/* 240 */	0240,	0241,	0242,	0243,	0244,	0245,	0246,	0247,
/* 250 */	0250,	0251,	0252,	0253,	0254,	0255,	0256,	0257,
/* 260 */	0260,	0261,	0262,	0263,	0264,	0265,	0266,	0267,
/* 270 */	0270,	0271,	0272,	0273,	0274,	0275,	0276,	0277,
/* 300 */	0300,	0301,	0302,	0303,	0304,	0305,	0306,	0307,
/* 310 */	0310,	0311,	0312,	0313,	0314,	0315,	0316,	0317,
/* 320 */	0320,	0321,	0322,	0323,	0324,	0325,	0326,	0327,
/* 330 */	0330,	0331,	0332,	0333,	0334,	0335,	0336,	0337,
/* 340 */	0340,	0341,	0342,	0343,	0344,	0345,	0346,	0347,
/* 350 */	0350,	0351,	0352,	0353,	0354,	0355,	0356,	0357,
/* 360 */	0360,	0361,	0362,	0363,	0364,	0365,	0366,	0367,
/*
 * WARNING: as for above ISO sets, \377 may be used.  Translate it to
 * itself.
 */
/* 370 */	0370,	0371,	0372,	0373,	0374,	0375,	0376,	0377,
};

/*
 * Input mapping table -- if an entry is non-zero, and XCASE is set,
 * when the corresponding character is typed preceded by "\" the escape
 * sequence is replaced by the table value.  Mostly used for
 * upper-case only terminals.
 */
static char	imaptab[256] = {
/* 000 */	0,	0,	0,	0,	0,	0,	0,	0,
/* 010 */	0,	0,	0,	0,	0,	0,	0,	0,
/* 020 */	0,	0,	0,	0,	0,	0,	0,	0,
/* 030 */	0,	0,	0,	0,	0,	0,	0,	0,
/* 040 */	0,	'|',	0,	0,	0,	0,	0,	'`',
/* 050 */	'{',	'}',	0,	0,	0,	0,	0,	0,
/* 060 */	0,	0,	0,	0,	0,	0,	0,	0,
/* 070 */	0,	0,	0,	0,	0,	0,	0,	0,
/* 100 */	0,	0,	0,	0,	0,	0,	0,	0,
/* 110 */	0,	0,	0,	0,	0,	0,	0,	0,
/* 120 */	0,	0,	0,	0,	0,	0,	0,	0,
/* 130 */	0,	0,	0,	0,	'\\',	0,	'~',	0,
/* 140 */	0,	'A',	'B',	'C',	'D',	'E',	'F',	'G',
/* 150 */	'H',	'I',	'J',	'K',	'L',	'M',	'N',	'O',
/* 160 */	'P',	'Q',	'R',	'S',	'T',	'U',	'V',	'W',
/* 170 */	'X',	'Y',	'Z',	0,	0,	0,	0,	0,
/* 200-377 aren't mapped */
};

/*
 * Output mapping table -- if an entry is non-zero, and XCASE is set,
 * the corresponding character is printed as "\" followed by the table
 * value.  Mostly used for upper-case only terminals.
 */
static char	omaptab[256] = {
/* 000 */	0,	0,	0,	0,	0,	0,	0,	0,
/* 010 */	0,	0,	0,	0,	0,	0,	0,	0,
/* 020 */	0,	0,	0,	0,	0,	0,	0,	0,
/* 030 */	0,	0,	0,	0,	0,	0,	0,	0,
/* 040 */	0,	0,	0,	0,	0,	0,	0,	0,
/* 050 */	0,	0,	0,	0,	0,	0,	0,	0,
/* 060 */	0,	0,	0,	0,	0,	0,	0,	0,
/* 070 */	0,	0,	0,	0,	0,	0,	0,	0,
/* 100 */	0,	'A',	'B',	'C',	'D',	'E',	'F',	'G',
/* 110 */	'H',	'I',	'J',	'K',	'L',	'M',	'N',	'O',
/* 120 */	'P',	'Q',	'R',	'S',	'T',	'U',	'V',	'W',
/* 130 */	'X',	'Y',	'Z',	0,	0,	0,	0,	0,
/* 140 */	'\'',	0,	0,	0,	0,	0,	0,	0,
/* 150 */	0,	0,	0,	0,	0,	0,	0,	0,
/* 160 */	0,	0,	0,	0,	0,	0,	0,	0,
/* 170 */	0,	0,	0,	'(',	'!',	')',	'^',	0,
/* 200-377 aren't mapped */
};

/*
 * Translation table for TS_MEUC output without OLCUC.  All printing ASCII
 * characters translate to themselves.  All other _bytes_ have a zero in
 * the table, which stops the copying.  This and the following table exist
 * only so we can use the existing movtuc processing with or without OLCUC.
 * Maybe it speeds up something...because we can copy a block of characters
 * by only looking for zeros in the table.
 *
 * If we took the simple expedient of DISALLOWING "olcuc" with multi-byte
 * processing, we could rid ourselves of both these tables and save 512 bytes;
 * seriously, it doesn't make much sense to use olcuc with multi-byte, and
 * it will probably never be used.  Consideration should be given to disallowing
 * the combination TS_MEUC & OLCUC.
 */
static unsigned char enotrantab[256] = {
/* 000 */	0,	0,	0,	0,	0,	0,	0,	0,
/* 010 */	0,	0,	0,	0,	0,	0,	0,	0,
/* 020 */	0,	0,	0,	0,	0,	0,	0,	0,
/* 030 */	0,	0,	0,	0,	0,	0,	0,	0,
/* 040 */	' ',	'!',	'"',	'#',	'$',	'%',	'&',	'\'',
/* 050 */	'(',	')',	'*',	'+',	',',	'-',	'.',	'/',
/* 060 */	'0',	'1',	'2',	'3',	'4',	'5',	'6',	'7',
/* 070 */	'8',	'9',	':',	';',	'<',	'=',	'>',	'?',
/* 100 */	'@',	'A',	'B',	'C',	'D',	'E',	'F',	'G',
/* 110 */	'H',	'I',	'J',	'K',	'L',	'M',	'N',	'O',
/* 120 */	'P',	'Q',	'R',	'S',	'T',	'U',	'V',	'W',
/* 130 */	'X',	'Y',	'Z',	'[',	'\\',	']',	'^',	'_',
/* 140 */	'`',	'a',	'b',	'c',	'd',	'e',	'f',	'g',
/* 150 */	'h',	'i',	'j',	'k',	'l',	'm',	'n',	'o',
/* 160 */	'p',	'q',	'r',	's',	't',	'u',	'v',	'w',
/* 170 */	'x',	'y',	'z',	'{',	'|',	'}',	'~',	0,
/* 200 - 377 aren't mapped (they're stoppers). */
};

/*
 * Translation table for TS_MEUC output with OLCUC.  All printing ASCII
 * translate to themselves, except for lower-case letters which translate
 * to their upper-case equivalents.  All other bytes have a zero in
 * the table, which stops the copying.  Useless for ISO Latin Alphabet
 * translations, but *sigh* OLCUC is really only defined for ASCII anyway.
 * We only have this table so we can use the existing OLCUC processing with
 * TS_MEUC set (multi-byte mode).  Nobody would ever think of actually
 * _using_ it...would they?
 */
static unsigned char elcuctab[256] = {
/* 000 */	0,	0,	0,	0,	0,	0,	0,	0,
/* 010 */	0,	0,	0,	0,	0,	0,	0,	0,
/* 020 */	0,	0,	0,	0,	0,	0,	0,	0,
/* 030 */	0,	0,	0,	0,	0,	0,	0,	0,
/* 040 */	' ',	'!',	'"',	'#',	'$',	'%',	'&',	'\'',
/* 050 */	'(',	')',	'*',	'+',	',',	'-',	'.',	'/',
/* 060 */	'0',	'1',	'2',	'3',	'4',	'5',	'6',	'7',
/* 070 */	'8',	'9',	':',	';',	'<',	'=',	'>',	'?',
/* 100 */	'@',	'A',	'B',	'C',	'D',	'E',	'F',	'G',
/* 110 */	'H',	'I',	'J',	'K',	'L',	'M',	'N',	'O',
/* 120 */	'P',	'Q',	'R',	'S',	'T',	'U',	'V',	'W',
/* 130 */	'X',	'Y',	'Z',	'[',	'\\',	']',	'^',	'_',
/* 140 */	'`',	'A',	'B',	'C',	'D',	'E',	'F',	'G',
/* 150 */	'H',	'I',	'J',	'K',	'L',	'M',	'N',	'O',
/* 160 */	'P',	'Q',	'R',	'S',	'T',	'U',	'V',	'W',
/* 170 */	'X',	'Y',	'Z',	'{',	'|',	'}',	'~',	0,
/* 200 - 377 aren't mapped (they're stoppers). */
};

static struct streamtab ldtrinfo;

static struct fmodsw fsw = {
	"ldterm",
	&ldtrinfo,
	D_MTQPAIR | D_MP | _D_SINGLE_INSTANCE
};

static struct modlstrmod modlstrmod = {
	&mod_strmodops, "terminal line discipline", &fsw
};


static struct modlinkage modlinkage = {
	MODREV_1, &modlstrmod, NULL
};


int
_init(void)
{
	return (mod_install(&modlinkage));
}

int
_fini(void)
{
	return (mod_remove(&modlinkage));
}

int
_info(struct modinfo *modinfop)
{
	return (mod_info(&modlinkage, modinfop));
}


static int	ldtermopen(queue_t *, dev_t *, int, int, cred_t *);
static int	ldtermclose(queue_t *, int, cred_t *);
static void	ldtermrput(queue_t *, mblk_t *);
static void	ldtermrsrv(queue_t *);
static int	ldtermrmsg(queue_t *, mblk_t *);
static void	ldtermwput(queue_t *, mblk_t *);
static void	ldtermwsrv(queue_t *);
static int	ldtermwmsg(queue_t *, mblk_t *);
static mblk_t	*ldterm_docanon(unsigned char, mblk_t *, size_t, queue_t *,
				ldtermstd_state_t *, int *);
static int	ldterm_unget(ldtermstd_state_t *);
static void	ldterm_trim(ldtermstd_state_t *);
static void	ldterm_rubout(unsigned char, queue_t *, size_t,
				ldtermstd_state_t *);
static int	ldterm_tabcols(ldtermstd_state_t *);
static void	ldterm_erase(queue_t *, size_t, ldtermstd_state_t *);
static void	ldterm_werase(queue_t *, size_t, ldtermstd_state_t *);
static void	ldterm_kill(queue_t *, size_t, ldtermstd_state_t *);
static void	ldterm_reprint(queue_t *, size_t, ldtermstd_state_t *);
static mblk_t	*ldterm_dononcanon(mblk_t *, mblk_t *, size_t, queue_t *,
					ldtermstd_state_t *);
static int	ldterm_echo(unsigned char, queue_t *, size_t,
				ldtermstd_state_t *);
static void	ldterm_outchar(unsigned char, queue_t *, size_t,
				ldtermstd_state_t *);
static void	ldterm_outstring(unsigned char *, int, queue_t *, size_t,
					ldtermstd_state_t *tp);
static mblk_t	*newmsg(ldtermstd_state_t *);
static void	ldterm_msg_upstream(queue_t *, ldtermstd_state_t *);
static void	ldterm_wenable(void *);
static mblk_t	*ldterm_output_msg(queue_t *, mblk_t *, mblk_t **,
				ldtermstd_state_t *, size_t, int);
static void	ldterm_flush_output(unsigned char, queue_t *,
					ldtermstd_state_t *);
static void	ldterm_dosig(queue_t *, int, unsigned char, int, int);
static void	ldterm_do_ioctl(queue_t *, mblk_t *);
static int	chgstropts(struct termios *, ldtermstd_state_t *, queue_t *);
static void	ldterm_ioctl_reply(queue_t *, mblk_t *);
static void	vmin_satisfied(queue_t *, ldtermstd_state_t *, int);
static void	vmin_settimer(queue_t *);
static void	vmin_timed_out(void *);
static void	ldterm_adjust_modes(ldtermstd_state_t *);
static void	ldterm_eucwarn(ldtermstd_state_t *);
static void	cp_eucwioc(eucioc_t *, eucioc_t *, int);
static int	ldterm_codeset(uchar_t, uchar_t);

static void	ldterm_csi_erase(queue_t *, size_t, ldtermstd_state_t *);
static void	ldterm_csi_werase(queue_t *, size_t, ldtermstd_state_t *);

static uchar_t	ldterm_utf8_width(uchar_t *, int);

/* Codeset type specific methods for EUC, PCCS, and, UTF-8 codeset types. */
static int	__ldterm_dispwidth_euc(uchar_t, void *, int);
static int	__ldterm_memwidth_euc(uchar_t, void *);

static int	__ldterm_dispwidth_pccs(uchar_t, void *, int);
static int	__ldterm_memwidth_pccs(uchar_t, void *);

static int	__ldterm_dispwidth_utf8(uchar_t, void *, int);
static int	__ldterm_memwidth_utf8(uchar_t, void *);

static const ldterm_cs_methods_t cs_methods[LDTERM_CS_TYPE_MAX + 1] = {
	{
		NULL,
		NULL
	},
	{
		__ldterm_dispwidth_euc,
		__ldterm_memwidth_euc
	},
	{
		__ldterm_dispwidth_pccs,
		__ldterm_memwidth_pccs
	},
	{
		__ldterm_dispwidth_utf8,
		__ldterm_memwidth_utf8
	}
};

/*
 * The default codeset is presumably C locale's ISO 646 in EUC but
 * the data structure at below defined as the default codeset data also
 * support any single byte (EUC) locales.
 */
static const ldterm_cs_data_t default_cs_data = {
	LDTERM_DATA_VERSION,
	LDTERM_CS_TYPE_EUC,
	(uchar_t)0,
	(uchar_t)0,
	(char *)NULL,
	{
		'\0', '\0', '\0', '\0',
		'\0', '\0', '\0', '\0',
		'\0', '\0', '\0', '\0',
		'\0', '\0', '\0', '\0',
		'\0', '\0', '\0', '\0',
		'\0', '\0', '\0', '\0',
		'\0', '\0', '\0', '\0',
		'\0', '\0', '\0', '\0',
		'\0', '\0', '\0', '\0',
		'\0', '\0', '\0', '\0'
	}
};

/*
 * The following tables are from either u8_textprep.c or uconv.c at
 * usr/src/common/unicode/. The tables are used to figure out corresponding
 * UTF-8 character byte lengths and also the validity of given character bytes.
 */
extern const int8_t u8_number_of_bytes[];
extern const uchar_t u8_masks_tbl[];
extern const uint8_t u8_valid_min_2nd_byte[];
extern const uint8_t u8_valid_max_2nd_byte[];

/*
 * Unicode character width definition tables from uwidth.c:
 */
extern const ldterm_unicode_data_cell_t ldterm_ucode[][16384];

#ifdef LDDEBUG
int	ldterm_debug = 0;
#define	DEBUG1(a)	if (ldterm_debug == 1) printf a
#define	DEBUG2(a)	if (ldterm_debug >= 2) printf a	/* allocations */
#define	DEBUG3(a)	if (ldterm_debug >= 3) printf a	/* M_CTL Stuff */
#define	DEBUG4(a)	if (ldterm_debug >= 4) printf a	/* M_READ Stuff */
#define	DEBUG5(a)	if (ldterm_debug >= 5) printf a
#define	DEBUG6(a)	if (ldterm_debug >= 6) printf a
#define	DEBUG7(a)	if (ldterm_debug >= 7) printf a
#else
#define	DEBUG1(a)
#define	DEBUG2(a)
#define	DEBUG3(a)
#define	DEBUG4(a)
#define	DEBUG5(a)
#define	DEBUG6(a)
#define	DEBUG7(a)
#endif		/* LDDEBUG */


/*
 * Since most of the buffering occurs either at the stream head or in
 * the "message currently being assembled" buffer, we have a
 * relatively small input queue, so that blockages above us get
 * reflected fairly quickly to the module below us.  We also have a
 * small maximum packet size, since you can put a message of that
 * size on an empty queue no matter how much bigger than the high
 * water mark it is.
 */
static struct module_info ldtermmiinfo = {
	0x0bad,
	"ldterm",
	0,
	_TTY_BUFSIZ,
	_TTY_BUFSIZ,
	LOWAT
};


static struct qinit ldtermrinit = {
	(int (*)())ldtermrput,
	(int (*)())ldtermrsrv,
	ldtermopen,
	ldtermclose,
	NULL,
	&ldtermmiinfo
};


static struct module_info ldtermmoinfo = {
	0x0bad,
	"ldterm",
	0,
	INFPSZ,
	1,
	0
};


static struct qinit ldtermwinit = {
	(int (*)())ldtermwput,
	(int (*)())ldtermwsrv,
	ldtermopen,
	ldtermclose,
	NULL,
	&ldtermmoinfo
};


static struct streamtab ldtrinfo = {
	&ldtermrinit,
	&ldtermwinit,
	NULL,
	NULL
};

/*
 * Dummy qbufcall callback routine used by open and close.
 * The framework will wake up qwait_sig when we return from
 * this routine (as part of leaving the perimeters.)
 * (The framework enters the perimeters before calling the qbufcall() callback
 * and leaves the perimeters after the callback routine has executed. The
 * framework performs an implicit wakeup of any thread in qwait/qwait_sig
 * when it leaves the perimeter. See qwait(9E).)
 */
/* ARGSUSED */
static void
dummy_callback(void *arg)
{}


static mblk_t *
open_ioctl(queue_t *q, uint_t cmd)
{
	mblk_t *mp;
	bufcall_id_t id;
	int retv;

	while ((mp = mkiocb(cmd)) == NULL) {
		id = qbufcall(q, sizeof (struct iocblk), BPRI_MED,
		    dummy_callback, NULL);
		retv = qwait_sig(q);
		qunbufcall(q, id);
		if (retv == 0)
			break;
	}
	return (mp);
}

static mblk_t *
open_mblk(queue_t *q, size_t len)
{
	mblk_t *mp;
	bufcall_id_t id;
	int retv;

	while ((mp = allocb(len, BPRI_MED)) == NULL) {
		id = qbufcall(q, len, BPRI_MED, dummy_callback, NULL);
		retv = qwait_sig(q);
		qunbufcall(q, id);
		if (retv == 0)
			break;
	}
	return (mp);
}

/*
 * Line discipline open.
 */
/* ARGSUSED1 */
static int
ldtermopen(queue_t *q, dev_t *devp, int oflag, int sflag, cred_t *crp)
{
	ldtermstd_state_t *tp;
	mblk_t *bp, *qryp;
	int len;
	struct stroptions *strop;
	struct termios *termiosp;
	queue_t *wq;

	if (q->q_ptr != NULL) {
		return (0);	/* already attached */
	}

	tp = (ldtermstd_state_t *)kmem_zalloc(sizeof (ldtermstd_state_t),
	    KM_SLEEP);

	/*
	 * Get termios defaults.  These are stored as
	 * a property in the "options" node.
	 */
	if (ddi_getlongprop(DDI_DEV_T_ANY, ddi_root_node(), DDI_PROP_NOTPROM,
	    "ttymodes", (caddr_t)&termiosp, &len) == DDI_PROP_SUCCESS &&
	    len == sizeof (struct termios)) {
		tp->t_modes = *termiosp;
		tp->t_amodes = *termiosp;
		kmem_free(termiosp, len);
	} else {
		/*
		 * Gack!  Whine about it.
		 */
		cmn_err(CE_WARN, "ldterm: Couldn't get ttymodes property!");
	}
	bzero(&tp->t_dmodes, sizeof (struct termios));

	tp->t_state = 0;

	tp->t_line = 0;
	tp->t_col = 0;

	tp->t_rocount = 0;
	tp->t_rocol = 0;

	tp->t_message = NULL;
	tp->t_endmsg = NULL;
	tp->t_msglen = 0;
	tp->t_rd_request = 0;

	tp->t_echomp = NULL;
	tp->t_iocid = 0;
	tp->t_wbufcid = 0;
	tp->t_vtid = 0;

	q->q_ptr = (caddr_t)tp;
	WR(q)->q_ptr = (caddr_t)tp;
	/*
	 * The following for EUC and also non-EUC codesets:
	 */
	tp->t_codeset = tp->t_eucleft = tp->t_eucign = tp->t_scratch_len = 0;
	bzero(&tp->eucwioc, EUCSIZE);
	tp->eucwioc.eucw[0] = 1;	/* ASCII mem & screen width */
	tp->eucwioc.scrw[0] = 1;
	tp->t_maxeuc = 1;	/* the max len in bytes of an EUC char */
	tp->t_eucp = NULL;
	tp->t_eucp_mp = NULL;
	tp->t_eucwarn = 0;	/* no bad chars seen yet */

	tp->t_csdata = default_cs_data;
	tp->t_csmethods = cs_methods[LDTERM_CS_TYPE_EUC];

	qprocson(q);

	/*
	 * Find out if the module below us does canonicalization; if
	 * so, we won't do it ourselves.
	 */

	if ((qryp = open_ioctl(q, MC_CANONQUERY)) == NULL)
		goto open_abort;

	/*
	 * Reformulate as an M_CTL message. The actual data will
	 * be in the b_cont field.
	 */
	qryp->b_datap->db_type = M_CTL;
	wq = OTHERQ(q);
	putnext(wq, qryp);

	/* allocate a TCSBRK ioctl in case we'll need it on close */
	if ((qryp = open_ioctl(q, TCSBRK)) == NULL)
		goto open_abort;
	tp->t_drainmsg = qryp;
	if ((bp = open_mblk(q, sizeof (int))) == NULL)
		goto open_abort;
	qryp->b_cont = bp;

	/*
	 * Find out if the underlying driver supports proper POSIX close
	 * semantics.  If not, we'll have to approximate it using TCSBRK.  If
	 * it does, it will respond with MC_HAS_POSIX, and we'll catch that in
	 * the ldtermrput routine.
	 *
	 * When the ldterm_drain_limit tunable is set to zero, we behave the
	 * same as old ldterm: don't send this new message, and always use
	 * TCSBRK during close.
	 */
	if (ldterm_drain_limit != 0) {
		if ((qryp = open_ioctl(q, MC_POSIXQUERY)) == NULL)
			goto open_abort;
		qryp->b_datap->db_type = M_CTL;
		putnext(wq, qryp);
	}

	/* prepare to clear the water marks on close */
	if ((bp = open_mblk(q, sizeof (struct stroptions))) == NULL)
		goto open_abort;
	tp->t_closeopts = bp;

	/*
	 * Set the high-water and low-water marks on the stream head
	 * to values appropriate for a terminal.  Also set the "vmin"
	 * and "vtime" values to 1 and 0, turn on message-nondiscard
	 * mode (as we're in ICANON mode), and turn on "old-style
	 * NODELAY" mode.
	 */
	if ((bp = open_mblk(q, sizeof (struct stroptions))) == NULL)
		goto open_abort;
	strop = (struct stroptions *)bp->b_wptr;
	strop->so_flags = SO_READOPT|SO_HIWAT|SO_LOWAT|SO_NDELON|SO_ISTTY;
	strop->so_readopt = RMSGN;
	strop->so_hiwat = _TTY_BUFSIZ;
	strop->so_lowat = LOWAT;
	bp->b_wptr += sizeof (struct stroptions);
	bp->b_datap->db_type = M_SETOPTS;
	putnext(q, bp);

	return (0);		/* this can become a controlling TTY */

open_abort:
	qprocsoff(q);
	q->q_ptr = NULL;
	WR(q)->q_ptr = NULL;
	freemsg(tp->t_closeopts);
	freemsg(tp->t_drainmsg);
	/* Dump the state structure */
	kmem_free(tp, sizeof (ldtermstd_state_t));
	return (EINTR);
}

struct close_timer {
	timeout_id_t id;
	ldtermstd_state_t *tp;
};

static void
drain_timed_out(void *arg)
{
	struct close_timer *ctp = arg;

	ctp->id = 0;
	ctp->tp->t_state &= ~TS_IOCWAIT;
}

/* ARGSUSED2 */
static int
ldtermclose(queue_t *q, int cflag, cred_t *crp)
{
	ldtermstd_state_t *tp = (ldtermstd_state_t *)q->q_ptr;
	struct stroptions *strop;
	mblk_t *bp;
	struct close_timer cltimer;

	/*
	 * If we have an outstanding vmin timeout, cancel it.
	 */
	tp->t_state |= TS_CLOSE;
	if (tp->t_vtid != 0)
		(void) quntimeout(q, tp->t_vtid);
	tp->t_vtid = 0;

	/*
	 * Cancel outstanding qbufcall request.
	 */
	if (tp->t_wbufcid != 0)
		qunbufcall(q, tp->t_wbufcid);

	/*
	 * Reset the high-water and low-water marks on the stream
	 * head (?), turn on byte-stream mode, and turn off
	 * "old-style NODELAY" mode.
	 */
	bp = tp->t_closeopts;
	strop = (struct stroptions *)bp->b_wptr;
	strop->so_flags = SO_READOPT|SO_NDELOFF;
	strop->so_readopt = RNORM;
	bp->b_wptr += sizeof (struct stroptions);
	bp->b_datap->db_type = M_SETOPTS;
	putnext(q, bp);

	if (cflag & (FNDELAY|FNONBLOCK)) {
		freemsg(tp->t_drainmsg);
	} else if ((bp = tp->t_drainmsg) != NULL) {
		struct iocblk *iocb;

		/*
		 * If the driver isn't known to have POSIX close semantics,
		 * then we have to emulate this the old way.  This is done by
		 * sending down TCSBRK,1 to drain the output and waiting for
		 * the reply.
		 */
		iocb = (struct iocblk *)bp->b_rptr;
		iocb->ioc_count = sizeof (int);
		*(int *)bp->b_cont->b_rptr = 1;
		bp->b_cont->b_wptr += sizeof (int);
		tp->t_state |= TS_IOCWAIT;
		tp->t_iocid = iocb->ioc_id;
		if (!putq(WR(q), bp))
			putnext(WR(q), bp);

		/*
		 * If we're not able to receive signals at this point, then
		 * launch a timer.  This timer will prevent us from waiting
		 * forever for a signal that won't arrive.
		 */
		cltimer.id = 0;
		if (!ddi_can_receive_sig() && ldterm_drain_limit != 0) {
			cltimer.tp = tp;
			cltimer.id = qtimeout(q, drain_timed_out, &cltimer,
			    drv_usectohz(ldterm_drain_limit));
		}

		/*
		 * Note that the read side of ldterm and the qtimeout are
		 * protected by D_MTQPAIR, so no additional locking is needed
		 * here.
		 */
		while (tp->t_state & TS_IOCWAIT) {
			if (qwait_sig(q) == 0)
				break;
		}
		if (cltimer.id != 0)
			(void) quntimeout(q, cltimer.id);
	}

	/*
	 * From here to the end, the routine does not sleep and does not
	 * reference STREAMS, so it's guaranteed to run to completion.
	 */

	qprocsoff(q);

	freemsg(tp->t_message);
	freemsg(tp->t_eucp_mp);

	/* Dump the state structure, then unlink it */
	if (tp->t_csdata.locale_name != NULL)
		kmem_free(tp->t_csdata.locale_name,
		    strlen(tp->t_csdata.locale_name) + 1);
	kmem_free(tp, sizeof (ldtermstd_state_t));
	q->q_ptr = NULL;
	return (0);
}


/*
 * Put procedure for input from driver end of stream (read queue).
 */
static void
ldtermrput(queue_t *q, mblk_t *mp)
{
	ldtermstd_state_t *tp;
	unsigned char c;
	queue_t *wrq = WR(q);		/* write queue of ldterm mod */
	queue_t *nextq = q->q_next;	/* queue below us */
	mblk_t *bp;
	struct iocblk *qryp;
	unsigned char *readp;
	unsigned char *writep;
	struct termios *emodes;		/* effective modes set by driver */
	int dbtype;

	tp = (ldtermstd_state_t *)q->q_ptr;
	/*
	 * We received our ack from the driver saying there is nothing left to
	 * shovel out, so wake up the close routine.
	 */
	dbtype = DB_TYPE(mp);
	if ((dbtype == M_IOCACK || dbtype == M_IOCNAK) &&
	    (tp->t_state & (TS_CLOSE|TS_IOCWAIT)) == (TS_CLOSE|TS_IOCWAIT)) {
		struct iocblk *iocp = (struct iocblk *)mp->b_rptr;

		if (iocp->ioc_id == tp->t_iocid) {
			tp->t_state &= ~TS_IOCWAIT;
			freemsg(mp);
			return;
		}
	}

	switch (dbtype) {

	default:
		(void) putq(q, mp);
		return;

		/*
		 * Send these up unmolested
		 *
		 */
	case M_PCSIG:
	case M_SIG:
	case M_IOCNAK:

		putnext(q, mp);
		return;

	case M_IOCACK:

		ldterm_ioctl_reply(q, mp);
		return;

	case M_BREAK:

		/*
		 * Parity errors are sent up as M_BREAKS with single
		 * character data (formerly handled in the driver)
		 */
		if (mp->b_wptr - mp->b_rptr == 1) {
			/*
			 * IGNPAR	PARMRK		RESULT
			 * off		off		0
			 * off		on		3 byte sequence
			 * on		either		ignored
			 */
			if (!(tp->t_amodes.c_iflag & IGNPAR)) {
				mp->b_wptr = mp->b_rptr;
				if (tp->t_amodes.c_iflag & PARMRK) {
					unsigned char c;

					c = *mp->b_rptr;
					freemsg(mp);
					if ((mp = allocb(3, BPRI_HI)) == NULL) {
						cmn_err(CE_WARN,
						    "ldtermrput: no blocks");
						return;
					}
					mp->b_datap->db_type = M_DATA;
					*mp->b_wptr++ = (uchar_t)'\377';
					*mp->b_wptr++ = '\0';
					*mp->b_wptr++ = c;
					putnext(q, mp);
				} else {
					mp->b_datap->db_type = M_DATA;
					*mp->b_wptr++ = '\0';
					putnext(q, mp);
				}
			} else {
				freemsg(mp);
			}
			return;
		}
		/*
		 * We look at the apparent modes here instead of the
		 * effective modes. Effective modes cannot be used if
		 * IGNBRK, BRINT and PARMRK have been negotiated to
		 * be handled by the driver. Since M_BREAK should be
		 * sent upstream only if break processing was not
		 * already done, it should be ok to use the apparent
		 * modes.
		 */

		if (!(tp->t_amodes.c_iflag & IGNBRK)) {
			if (tp->t_amodes.c_iflag & BRKINT) {
				ldterm_dosig(q, SIGINT, '\0', M_PCSIG, FLUSHRW);
				freemsg(mp);
			} else if (tp->t_amodes.c_iflag & PARMRK) {
				/*
				 * Send '\377','\0', '\0'.
				 */
				freemsg(mp);
				if ((mp = allocb(3, BPRI_HI)) == NULL) {
					cmn_err(CE_WARN,
					    "ldtermrput: no blocks");
					return;
				}
				mp->b_datap->db_type = M_DATA;
				*mp->b_wptr++ = (uchar_t)'\377';
				*mp->b_wptr++ = '\0';
				*mp->b_wptr++ = '\0';
				putnext(q, mp);
			} else {
				/*
				 * Act as if a '\0' came in.
				 */
				freemsg(mp);
				if ((mp = allocb(1, BPRI_HI)) == NULL) {
					cmn_err(CE_WARN,
					    "ldtermrput: no blocks");
					return;
				}
				mp->b_datap->db_type = M_DATA;
				*mp->b_wptr++ = '\0';
				putnext(q, mp);
			}
		} else {
			freemsg(mp);
		}
		return;

	case M_CTL:
		DEBUG3(("ldtermrput: M_CTL received\n"));
		/*
		 * The M_CTL has been standardized to look like an
		 * M_IOCTL message.
		 */

		if ((mp->b_wptr - mp->b_rptr) != sizeof (struct iocblk)) {
			DEBUG3((
			    "Non standard M_CTL received by ldterm module\n"));
			/* May be for someone else; pass it on */
			putnext(q, mp);
			return;
		}
		qryp = (struct iocblk *)mp->b_rptr;

		switch (qryp->ioc_cmd) {

		case MC_PART_CANON:

			DEBUG3(("ldtermrput: M_CTL Query Reply\n"));
			if (!mp->b_cont) {
				DEBUG3(("No information in Query Message\n"));
				break;
			}
			if ((mp->b_cont->b_wptr - mp->b_cont->b_rptr) ==
			    sizeof (struct termios)) {
				DEBUG3(("ldtermrput: M_CTL GrandScheme\n"));
				/* elaborate turning off scheme */
				emodes = (struct termios *)mp->b_cont->b_rptr;
				bcopy(emodes, &tp->t_dmodes,
					sizeof (struct termios));
				ldterm_adjust_modes(tp);
				break;
			} else {
				DEBUG3(("Incorrect query replysize\n"));
				break;
			}

		case MC_NO_CANON:
			tp->t_state |= TS_NOCANON;
			/*
			 * Note: this is very nasty.  It's not clear
			 * what the right thing to do with a partial
			 * message is; We throw it out
			 */
			if (tp->t_message != NULL) {
				freemsg(tp->t_message);
				tp->t_message = NULL;
				tp->t_endmsg = NULL;
				tp->t_msglen = 0;
				tp->t_rocount = 0;
				tp->t_rocol = 0;
				if (tp->t_state & TS_MEUC) {
					ASSERT(tp->t_eucp_mp);
					tp->t_eucp = tp->t_eucp_mp->b_rptr;
					tp->t_codeset = 0;
					tp->t_eucleft = 0;
				}
			}
			break;

		case MC_DO_CANON:
			tp->t_state &= ~TS_NOCANON;
			break;

		case MC_HAS_POSIX:
			/* no longer any reason to drain from ldterm */
			if (ldterm_drain_limit != 0) {
				freemsg(tp->t_drainmsg);
				tp->t_drainmsg = NULL;
			}
			break;

		default:
			DEBUG3(("Unknown M_CTL Message\n"));
			break;
		}
		putnext(q, mp);	/* In case anyone else has to see it */
		return;

	case M_FLUSH:
		/*
		 * Flush everything we haven't looked at yet.
		 */

		if ((tp->t_state & TS_ISPTSTTY) && (*mp->b_rptr & FLUSHBAND))
			flushband(q, *(mp->b_rptr + 1), FLUSHDATA);
		else
			flushq(q, FLUSHDATA);

		/*
		 * Flush everything we have looked at.
		 */
		freemsg(tp->t_message);
		tp->t_message = NULL;
		tp->t_endmsg = NULL;
		tp->t_msglen = 0;
		tp->t_rocount = 0;
		tp->t_rocol = 0;
		if (tp->t_state & TS_MEUC) {	/* EUC multi-byte */
			ASSERT(tp->t_eucp_mp);
			tp->t_eucp = tp->t_eucp_mp->b_rptr;
		}
		putnext(q, mp);	/* pass it on */

		/*
		 * Relieve input flow control
		 */
		if ((tp->t_modes.c_iflag & IXOFF) &&
		    (tp->t_state & TS_TBLOCK) &&
		    !(tp->t_state & TS_IFBLOCK) && q->q_count <= TTXOLO) {
			tp->t_state &= ~TS_TBLOCK;
			(void) putnextctl(wrq, M_STARTI);
			DEBUG1(("M_STARTI down\n"));
		}
		return;

	case M_DATA:
		break;
	}
	(void) drv_setparm(SYSRAWC, msgdsize(mp));

	/*
	 * Flow control: send "start input" message if blocked and
	 * our queue is below its low water mark.
	 */
	if ((tp->t_modes.c_iflag & IXOFF) && (tp->t_state & TS_TBLOCK) &&
	    !(tp->t_state & TS_IFBLOCK) && q->q_count <= TTXOLO) {
		tp->t_state &= ~TS_TBLOCK;
		(void) putnextctl(wrq, M_STARTI);
		DEBUG1(("M_STARTI down\n"));
	}
	/*
	 * If somebody below us ("intelligent" communications
	 * board, pseudo-tty controlled by an editor) is doing
	 * canonicalization, don't scan it for special characters.
	 */
	if (tp->t_state & TS_NOCANON) {
		(void) putq(q, mp);
		return;
	}
	bp = mp;

	do {
		readp = bp->b_rptr;
		writep = readp;
		if (tp->t_modes.c_iflag & (INLCR|IGNCR|ICRNL|IUCLC|IXON) ||
		    tp->t_modes.c_lflag & (ISIG|ICANON)) {
			/*
			 * We're doing some sort of non-trivial
			 * processing of input; look at every
			 * character.
			 */
			while (readp < bp->b_wptr) {
				c = *readp++;

				if (tp->t_modes.c_iflag & ISTRIP)
					c &= 0177;

				/*
				 * First, check that this hasn't been
				 * escaped with the "literal next"
				 * character.
				 */
				if (tp->t_state & TS_PLNCH) {
					tp->t_state &= ~TS_PLNCH;
					tp->t_modes.c_lflag &= ~FLUSHO;
					*writep++ = c;
					continue;
				}
				/*
				 * Setting a special character to NUL
				 * disables it, so if this character
				 * is NUL, it should not be compared
				 * with any of the special characters.
				 * It should, however, restart frozen
				 * output if IXON and IXANY are set.
				 */
				if (c == _POSIX_VDISABLE) {
					if (tp->t_modes.c_iflag & IXON &&
					    tp->t_state & TS_TTSTOP &&
					    tp->t_modes.c_lflag & IEXTEN &&
					    tp->t_modes.c_iflag & IXANY) {
						tp->t_state &=
						    ~(TS_TTSTOP|TS_OFBLOCK);
						(void) putnextctl(wrq, M_START);
					}
					tp->t_modes.c_lflag &= ~FLUSHO;
					*writep++ = c;
					continue;
				}
				/*
				 * If stopped, start if you can; if
				 * running, stop if you must.
				 */
				if (tp->t_modes.c_iflag & IXON) {
					if (tp->t_state & TS_TTSTOP) {
						if (c ==
						    tp->t_modes.c_cc[VSTART] ||
						    (tp->t_modes.c_lflag &
						    IEXTEN &&
						    tp->t_modes.c_iflag &
						    IXANY)) {
							tp->t_state &=
							    ~(TS_TTSTOP |
							    TS_OFBLOCK);
							(void) putnextctl(wrq,
							    M_START);
						}
					} else {
						if (c ==
						    tp->t_modes.c_cc[VSTOP]) {
							tp->t_state |=
							    TS_TTSTOP;
							(void) putnextctl(wrq,
							    M_STOP);
						}
					}
					if (c == tp->t_modes.c_cc[VSTOP] ||
					    c == tp->t_modes.c_cc[VSTART])
						continue;
				}
				/*
				 * Check for "literal next" character
				 * and "flush output" character.
				 * Note that we omit checks for ISIG
				 * and ICANON, since the IEXTEN
				 * setting subsumes them.
				 */
				if (tp->t_modes.c_lflag & IEXTEN) {
					if (c == tp->t_modes.c_cc[VLNEXT]) {
						/*
						 * Remember that we saw a
						 * "literal next" while
						 * scanning input, but leave
						 * leave it in the message so
						 * that the service routine
						 * can see it too.
						 */
						tp->t_state |= TS_PLNCH;
						tp->t_modes.c_lflag &= ~FLUSHO;
						*writep++ = c;
						continue;
					}
					if (c == tp->t_modes.c_cc[VDISCARD]) {
						ldterm_flush_output(c, wrq, tp);
						continue;
					}
				}
				tp->t_modes.c_lflag &= ~FLUSHO;

				/*
				 * Check for signal-generating
				 * characters.
				 */
				if (tp->t_modes.c_lflag & ISIG) {
					if (c == tp->t_modes.c_cc[VINTR]) {
						ldterm_dosig(q, SIGINT, c,
						    M_PCSIG, FLUSHRW);
						continue;
					}
					if (c == tp->t_modes.c_cc[VQUIT]) {
						ldterm_dosig(q, SIGQUIT, c,
						    M_PCSIG, FLUSHRW);
						continue;
					}
					if (c == tp->t_modes.c_cc[VSWTCH]) {
						/*
						 * Ancient SXT support; discard
						 * character without action.
						 */
						continue;
					}
					if (c == tp->t_modes.c_cc[VSUSP]) {
						ldterm_dosig(q, SIGTSTP, c,
						    M_PCSIG, FLUSHRW);
						continue;
					}
					if ((tp->t_modes.c_lflag & IEXTEN) &&
					    (c == tp->t_modes.c_cc[VDSUSP])) {
						ldterm_dosig(q, SIGTSTP, c,
						    M_SIG, 0);
						continue;
					}

					/*
					 * Consumers do not expect the ^T to be
					 * echoed out when we generate a
					 * VSTATUS.
					 */
					if (c == tp->t_modes.c_cc[VSTATUS]) {
						ldterm_dosig(q, SIGINFO, '\0',
						    M_PCSIG, FLUSHRW);
						continue;
					}
				}
				/*
				 * Throw away CR if IGNCR set, or
				 * turn it into NL if ICRNL set.
				 */
				if (c == '\r') {
					if (tp->t_modes.c_iflag & IGNCR)
						continue;
					if (tp->t_modes.c_iflag & ICRNL)
						c = '\n';
				} else {
					/*
					 * Turn NL into CR if INLCR
					 * set.
					 */
					if (c == '\n' &&
					    tp->t_modes.c_iflag & INLCR)
						c = '\r';
				}

				/*
				 * Map upper case input to lower case
				 * if IUCLC flag set.
				 */
				if (tp->t_modes.c_iflag & IUCLC &&
				    c >= 'A' && c <= 'Z')
					c += 'a' - 'A';

				/*
				 * Put the possibly-transformed
				 * character back in the message.
				 */
				*writep++ = c;
			}

			/*
			 * If we didn't copy some characters because
			 * we were ignoring them, fix the size of the
			 * data block by adjusting the write pointer.
			 * XXX This may result in a zero-length
			 * block; will this cause anybody gastric
			 * distress?
			 */
			bp->b_wptr -= (readp - writep);
		} else {
			/*
			 * We won't be doing anything other than
			 * possibly stripping the input.
			 */
			if (tp->t_modes.c_iflag & ISTRIP) {
				while (readp < bp->b_wptr)
					*writep++ = *readp++ & 0177;
			}
			tp->t_modes.c_lflag &= ~FLUSHO;
		}

	} while ((bp = bp->b_cont) != NULL);	/* next block, if any */

	/*
	 * Queue the message for service procedure if the
	 * queue is not empty or canputnext() fails or
	 * tp->t_state & TS_RESCAN is true.
	 */

	if (q->q_first != NULL || !bcanputnext(q, mp->b_band) ||
	    (tp->t_state & TS_RESCAN))
		(void) putq(q, mp);
	else
		(void) ldtermrmsg(q, mp);

	/*
	 * Flow control: send "stop input" message if our queue is
	 * approaching its high-water mark. The message will be
	 * dropped on the floor in the service procedure, if we
	 * cannot ship it up and we have had it upto our neck!
	 *
	 * Set QWANTW to ensure that the read queue service procedure
	 * gets run when nextq empties up again, so that it can
	 * unstop the input.
	 */
	if ((tp->t_modes.c_iflag & IXOFF) && !(tp->t_state & TS_TBLOCK) &&
	    q->q_count >= TTXOHI) {
		mutex_enter(QLOCK(nextq));
		nextq->q_flag |= QWANTW;
		mutex_exit(QLOCK(nextq));
		tp->t_state |= TS_TBLOCK;
		(void) putnextctl(wrq, M_STOPI);
		DEBUG1(("M_STOPI down\n"));
	}
}


/*
 * Line discipline input server processing.  Erase/kill and escape
 * ('\') processing, gathering into messages, upper/lower case input
 * mapping.
 */
static void
ldtermrsrv(queue_t *q)
{
	ldtermstd_state_t *tp;
	mblk_t *mp;

	tp = (ldtermstd_state_t *)q->q_ptr;

	if (tp->t_state & TS_RESCAN) {
		/*
		 * Canonicalization was turned on or off. Put the
		 * message being assembled back in the input queue,
		 * so that we rescan it.
		 */
		if (tp->t_message != NULL) {
			DEBUG5(("RESCAN WAS SET; put back in q\n"));
			if (tp->t_msglen != 0)
				(void) putbq(q, tp->t_message);
			else
				freemsg(tp->t_message);
			tp->t_message = NULL;
			tp->t_endmsg = NULL;
			tp->t_msglen = 0;
		}
		if (tp->t_state & TS_MEUC) {
			ASSERT(tp->t_eucp_mp);
			tp->t_eucp = tp->t_eucp_mp->b_rptr;
			tp->t_codeset = 0;
			tp->t_eucleft = 0;
		}
		tp->t_state &= ~TS_RESCAN;
	}

	while ((mp = getq(q)) != NULL) {
		if (!ldtermrmsg(q, mp))
			break;
	}

	/*
	 * Flow control: send start message if blocked and our queue
	 * is below its low water mark.
	 */
	if ((tp->t_modes.c_iflag & IXOFF) && (tp->t_state & TS_TBLOCK) &&
	    !(tp->t_state & TS_IFBLOCK) && q->q_count <= TTXOLO) {
		tp->t_state &= ~TS_TBLOCK;
		(void) putctl(WR(q), M_STARTI);
	}
}

/*
 * This routine is called from both ldtermrput and ldtermrsrv to
 * do the actual work of dealing with mp. Return 1 on sucesss and
 * 0 on failure.
 */
static int
ldtermrmsg(queue_t *q, mblk_t *mp)
{
	unsigned char c;
	int dofree;
	int status = 1;
	size_t   ebsize;
	mblk_t *bp;
	mblk_t *bpt;
	ldtermstd_state_t *tp;

	bpt = NULL;

	tp = (ldtermstd_state_t *)q->q_ptr;

	if (mp->b_datap->db_type <= QPCTL && !bcanputnext(q, mp->b_band)) {
		/*
		 * Stream head is flow controlled. If echo is
		 * turned on, flush the read side or send a
		 * bell down the line to stop input and
		 * process the current message.
		 * Otherwise(putbq) the user will not see any
		 * response to to the typed input. Typically
		 * happens if there is no reader process.
		 * Note that you will loose the data in this
		 * case if the data is coming too fast. There
		 * is an assumption here that if ECHO is
		 * turned on its some user typing the data on
		 * a terminal and its not network.
		 */
		if (tp->t_modes.c_lflag & ECHO) {
			if ((tp->t_modes.c_iflag & IMAXBEL) &&
			    (tp->t_modes.c_lflag & ICANON)) {
				freemsg(mp);
				if (canputnext(WR(q)))
					ldterm_outchar(CTRL('g'), WR(q), 4, tp);
				status = 0;
				goto echo;
			} else {
				(void) putctl1(q, M_FLUSH, FLUSHR);
			}
		} else {
			(void) putbq(q, mp);
			status = 0;
			goto out;	/* read side is blocked */
		}
	}
	switch (mp->b_datap->db_type) {

	default:
		putnext(q, mp);	/* pass it on */
		goto out;

	case M_HANGUP:
		/*
		 * Flush everything we haven't looked at yet.
		 */
		flushq(q, FLUSHDATA);

		/*
		 * Flush everything we have looked at.
		 */
		freemsg(tp->t_message);
		tp->t_message = NULL;
		tp->t_endmsg = NULL;
		tp->t_msglen = 0;
		/*
		 * XXX  should we set read request
		 * tp->t_rd_request to NULL?
		 */
		tp->t_rocount = 0;	/* if it hasn't been typed */
		tp->t_rocol = 0;	/* it hasn't been echoed :-) */
		if (tp->t_state & TS_MEUC) {
			ASSERT(tp->t_eucp_mp);
			tp->t_eucp = tp->t_eucp_mp->b_rptr;
		}
		/*
		 * Restart output, since it's probably got
		 * nowhere to go anyway, and we're probably
		 * not going to see another ^Q for a while.
		 */
		if (tp->t_state & TS_TTSTOP) {
			tp->t_state &= ~(TS_TTSTOP|TS_OFBLOCK);
			(void) putnextctl(WR(q), M_START);
		}
		/*
		 * This message will travel up the read
		 * queue, flushing as it goes, get turned
		 * around at the stream head, and travel back
		 * down the write queue, flushing as it goes.
		 */
		(void) putnextctl1(q, M_FLUSH, FLUSHW);

		/*
		 * This message will travel down the write
		 * queue, flushing as it goes, get turned
		 * around at the driver, and travel back up
		 * the read queue, flushing as it goes.
		 */
		(void) putctl1(WR(q), M_FLUSH, FLUSHR);

		/*
		 * Now that that's done, we send a SIGCONT
		 * upstream, followed by the M_HANGUP.
		 */
		/* (void) putnextctl1(q, M_PCSIG, SIGCONT); */
		putnext(q, mp);
		goto out;

	case M_IOCACK:

		/*
		 * Augment whatever information the driver is
		 * returning  with the information we supply.
		 */
		ldterm_ioctl_reply(q, mp);
		goto out;

	case M_DATA:
		break;
	}

	/*
	 * This is an M_DATA message.
	 */

	/*
	 * If somebody below us ("intelligent" communications
	 * board, pseudo-tty controlled by an editor) is
	 * doing canonicalization, don't scan it for special
	 * characters.
	 */
	if (tp->t_state & TS_NOCANON) {
		putnext(q, mp);
		goto out;
	}
	bp = mp;

	if ((bpt = newmsg(tp)) != NULL) {
		mblk_t *bcont;

		do {
			ASSERT(bp->b_wptr >= bp->b_rptr);
			ebsize = bp->b_wptr - bp->b_rptr;
			if (ebsize > EBSIZE)
				ebsize = EBSIZE;
			bcont = bp->b_cont;
			if (CANON_MODE) {
				/*
				 * By default, free the message once processed
				 */
				dofree = 1;

				/*
				 * update sysinfo canch
				 * character. The value of
				 * canch may vary as compared
				 * to character tty
				 * implementation.
				 */
				while (bp->b_rptr < bp->b_wptr) {
					c = *bp->b_rptr++;
					if ((bpt = ldterm_docanon(c,
					    bpt, ebsize, q, tp, &dofree)) ==
					    NULL)
						break;
				}
				/*
				 * Release this block or put back on queue.
				 */
				if (dofree)
					freeb(bp);
				else {
					(void) putbq(q, bp);
					break;
				}
			} else
				bpt = ldterm_dononcanon(bp, bpt, ebsize, q, tp);
			if (bpt == NULL) {
				cmn_err(CE_WARN,
				    "ldtermrsrv: out of blocks");
				freemsg(bcont);
				break;
			}
		} while ((bp = bcont) != NULL);
	}
echo:
	/*
	 * Send whatever we echoed downstream.
	 */
	if (tp->t_echomp != NULL) {
		if (canputnext(WR(q)))
			putnext(WR(q), tp->t_echomp);
		else
			freemsg(tp->t_echomp);
		tp->t_echomp = NULL;
	}

out:
	return (status);
}


/*
 * Do canonical mode input; check whether this character is to be
 * treated as a special character - if so, check whether it's equal
 * to any of the special characters and handle it accordingly.
 * Otherwise, just add it to the current line.
 */
static mblk_t *
ldterm_docanon(uchar_t c, mblk_t *bpt, size_t ebsize, queue_t *q,
    ldtermstd_state_t *tp, int *dofreep)
{
	queue_t *wrq = WR(q);
	int i;

	/*
	 * If the previous character was the "literal next"
	 * character, treat this character as regular input.
	 */
	if (tp->t_state & TS_SLNCH)
		goto escaped;

	/*
	 * Setting a special character to NUL disables it, so if this
	 * character is NUL, it should not be compared with any of
	 * the special characters.
	 */
	if (c == _POSIX_VDISABLE) {
		tp->t_state &= ~TS_QUOT;
		goto escaped;
	}
	/*
	 * If this character is the literal next character, echo it
	 * as '^', backspace over it, and record that fact.
	 */
	if ((tp->t_modes.c_lflag & IEXTEN) && c == tp->t_modes.c_cc[VLNEXT]) {
		if (tp->t_modes.c_lflag & ECHO)
			ldterm_outstring((unsigned char *)"^\b", 2, wrq,
			    ebsize, tp);
		tp->t_state |= TS_SLNCH;
		goto out;
	}
	/*
	 * Check for the editing character. If the display width of
	 * the last byte at the canonical buffer is not one and also
	 * smaller than or equal to UNKNOWN_WIDTH, the character at
	 * the end of the buffer is a multi-byte and/or multi-column
	 * character.
	 */
	if (c == tp->t_modes.c_cc[VERASE] || c == tp->t_modes.c_cc[VERASE2]) {
		if (tp->t_state & TS_QUOT) {
			/*
			 * Get rid of the backslash, and put the
			 * erase character in its place.
			 */
			ldterm_erase(wrq, ebsize, tp);
			bpt = tp->t_endmsg;
			goto escaped;
		} else {
			if ((tp->t_state & TS_MEUC) && tp->t_msglen &&
			    (*(tp->t_eucp - 1) != 1 &&
			    *(tp->t_eucp - 1) <= UNKNOWN_WIDTH))
				ldterm_csi_erase(wrq, ebsize, tp);
			else
				ldterm_erase(wrq, ebsize, tp);
			bpt = tp->t_endmsg;
			goto out;
		}
	}
	if ((tp->t_modes.c_lflag & IEXTEN) && c == tp->t_modes.c_cc[VWERASE]) {
		/*
		 * Do "ASCII word" or "multibyte character token/chunk" erase.
		 */
		if (tp->t_state & TS_MEUC)
			ldterm_csi_werase(wrq, ebsize, tp);
		else
			ldterm_werase(wrq, ebsize, tp);
		bpt = tp->t_endmsg;
		goto out;
	}
	if (c == tp->t_modes.c_cc[VKILL]) {
		if (tp->t_state & TS_QUOT) {
			/*
			 * Get rid of the backslash, and put the kill
			 * character in its place.
			 */
			ldterm_erase(wrq, ebsize, tp);
			bpt = tp->t_endmsg;
			goto escaped;
		} else {
			ldterm_kill(wrq, ebsize, tp);
			bpt = tp->t_endmsg;
			goto out;
		}
	}
	if ((tp->t_modes.c_lflag & IEXTEN) && c == tp->t_modes.c_cc[VREPRINT]) {
		ldterm_reprint(wrq, ebsize, tp);
		goto out;
	}
	/*
	 * If the preceding character was a backslash: if the current
	 * character is an EOF, get rid of the backslash and treat
	 * the EOF as data; if we're in XCASE mode and the current
	 * character is part of a backslash-X escape sequence,
	 * process it; otherwise, just treat the current character
	 * normally.
	 */
	if (tp->t_state & TS_QUOT) {
		tp->t_state &= ~TS_QUOT;
		if (c == tp->t_modes.c_cc[VEOF]) {
			/*
			 * EOF character. Since it's escaped, get rid
			 * of the backslash and put the EOF character
			 * in its place.
			 */
			ldterm_erase(wrq, ebsize, tp);
			bpt = tp->t_endmsg;
		} else {
			/*
			 * If we're in XCASE mode, and the current
			 * character is part of a backslash-X
			 * sequence, get rid of the backslash and
			 * replace the current character with what
			 * that sequence maps to.
			 */
			if ((tp->t_modes.c_lflag & XCASE) &&
			    imaptab[c] != '\0') {
				ldterm_erase(wrq, ebsize, tp);
				bpt = tp->t_endmsg;
				c = imaptab[c];
			}
		}
	} else {
		/*
		 * Previous character wasn't backslash; check whether
		 * this was the EOF character.
		 */
		if (c == tp->t_modes.c_cc[VEOF]) {
			/*
			 * EOF character. Don't echo it unless
			 * ECHOCTL is set, don't stuff it in the
			 * current line, but send the line up the
			 * stream.
			 */
			if ((tp->t_modes.c_lflag & ECHOCTL) &&
			    (tp->t_modes.c_lflag & IEXTEN) &&
			    (tp->t_modes.c_lflag & ECHO)) {
				i = ldterm_echo(c, wrq, ebsize, tp);
				while (i > 0) {
					ldterm_outchar('\b', wrq, ebsize, tp);
					i--;
				}
			}
			bpt->b_datap->db_type = M_DATA;
			ldterm_msg_upstream(q, tp);
			if (!canputnext(q)) {
				bpt = NULL;
				*dofreep = 0;
			} else {
				bpt = newmsg(tp);
				*dofreep = 1;
			}
			goto out;
		}
	}

escaped:
	/*
	 * First, make sure we can fit one WHOLE multi-byte char in the
	 * buffer.  This is one place where we have overhead even if
	 * not in multi-byte mode; the overhead is subtracting
	 * tp->t_maxeuc from MAX_CANON before checking.
	 *
	 * Allows MAX_CANON bytes in the buffer before throwing awaying
	 * the the overflow of characters.
	 */
	if ((tp->t_msglen > ((_TTY_BUFSIZ + 1) - (int)tp->t_maxeuc)) &&
	    !((tp->t_state & TS_MEUC) && tp->t_eucleft)) {

		/*
		 * Byte will cause line to overflow, or the next EUC
		 * won't fit: Ring the bell or discard all input, and
		 * don't save the byte away.
		 */
		if (tp->t_modes.c_iflag & IMAXBEL) {
			if (canputnext(wrq))
				ldterm_outchar(CTRL('g'), wrq, ebsize, tp);
			goto out;
		} else {
			/*
			 * MAX_CANON processing. free everything in
			 * the current line and start with the
			 * current character as the first character.
			 */
			DEBUG7(("ldterm_docanon: MAX_CANON processing\n"));
			freemsg(tp->t_message);
			tp->t_message = NULL;
			tp->t_endmsg = NULL;
			tp->t_msglen = 0;
			tp->t_rocount = 0;	/* if it hasn't been type */
			tp->t_rocol = 0;	/* it hasn't been echoed :-) */
			if (tp->t_state & TS_MEUC) {
				ASSERT(tp->t_eucp_mp);
				tp->t_eucp = tp->t_eucp_mp->b_rptr;
			}
			tp->t_state &= ~TS_SLNCH;
			bpt = newmsg(tp);
		}
	}
	/*
	 * Add the character to the current line.
	 */
	if (bpt->b_wptr >= bpt->b_datap->db_lim) {
		/*
		 * No more room in this mblk; save this one away, and
		 * allocate a new one.
		 */
		bpt->b_datap->db_type = M_DATA;
		if ((bpt = allocb(IBSIZE, BPRI_MED)) == NULL)
			goto out;

		/*
		 * Chain the new one to the end of the old one, and
		 * mark it as the last block in the current line.
		 */
		tp->t_endmsg->b_cont = bpt;
		tp->t_endmsg = bpt;
	}
	*bpt->b_wptr++ = c;
	tp->t_msglen++;		/* message length in BYTES */

	/*
	 * In multi-byte mode, we have to keep track of where we are.
	 * The first bytes of multi-byte chars get the full count for the
	 * whole character.  We don't do any column calculations
	 * here, but we need the information for when we do. We could
	 * come across cases where we are getting garbage on the
	 * line, but we're in multi-byte mode.  In that case, we may
	 * see ASCII controls come in the middle of what should have been a
	 * multi-byte character.  Call ldterm_eucwarn...eventually, a
	 * warning message will be printed about it.
	 */
	if (tp->t_state & TS_MEUC) {
		if (tp->t_eucleft) {	/* if in a multi-byte char already */
			--tp->t_eucleft;
			*tp->t_eucp++ = 0;	/* is a subsequent byte */
			if (c < (uchar_t)0x20)
				ldterm_eucwarn(tp);
		} else { /* is the first byte of a multi-byte, or is ASCII */
			if (ISASCII(c)) {
				*tp->t_eucp++ =
				    tp->t_csmethods.ldterm_dispwidth(c,
				    (void *)tp, tp->t_modes.c_lflag & ECHOCTL);
				tp->t_codeset = 0;
			} else {
				*tp->t_eucp++ =
				    tp->t_csmethods.ldterm_dispwidth(c,
				    (void *)tp, tp->t_modes.c_lflag & ECHOCTL);
				tp->t_eucleft =
				    tp->t_csmethods.ldterm_memwidth(c,
				    (void *)tp) - 1;
				tp->t_codeset = ldterm_codeset(
				    tp->t_csdata.codeset_type, c);
			}
		}
	}
	/*
	 * AT&T is concerned about the following but we aren't since
	 * we have already shipped code that works.
	 *
	 * EOL2/XCASE should be conditioned with IEXTEN to be truly
	 * POSIX conformant. This is going to cause problems for
	 * pre-SVR4.0 programs that don't know about IEXTEN. Hence
	 * EOL2/IEXTEN is not conditioned with IEXTEN.
	 */
	if (!(tp->t_state & TS_SLNCH) &&
	    (c == '\n' || (c != '\0' && (c == tp->t_modes.c_cc[VEOL] ||
	    (c == tp->t_modes.c_cc[VEOL2]))))) {
		/*
		 * || ((tp->t_modes.c_lflag & IEXTEN) && c ==
		 * tp->t_modes.c_cc[VEOL2]))))) {
		 */
		/*
		 * It's a line-termination character; send the line
		 * up the stream.
		 */
		bpt->b_datap->db_type = M_DATA;
		ldterm_msg_upstream(q, tp);
		if (tp->t_state & TS_MEUC) {
			ASSERT(tp->t_eucp_mp);
			tp->t_eucp = tp->t_eucp_mp->b_rptr;
		}
		if ((bpt = newmsg(tp)) == NULL)
			goto out;
	} else {
		/*
		 * Character was escaped with LNEXT.
		 */
		if (tp->t_rocount++ == 0)
			tp->t_rocol = tp->t_col;
		tp->t_state &= ~(TS_SLNCH|TS_QUOT);
		/*
		 * If the current character is a single byte and single
		 * column character and it is the backslash character and
		 * IEXTEN, then the state will have TS_QUOT.
		 */
		if ((c == '\\') && (tp->t_modes.c_lflag & IEXTEN) &&
		    (!(tp->t_state & TS_MEUC) ||
		    ((tp->t_state & TS_MEUC) && (!tp->t_eucleft))))
			tp->t_state |= TS_QUOT;
	}

	/*
	 * Echo it.
	 */
	if (tp->t_state & TS_ERASE) {
		tp->t_state &= ~TS_ERASE;
		if (tp->t_modes.c_lflag & ECHO)
			ldterm_outchar('/', wrq, ebsize, tp);
	}
	if (tp->t_modes.c_lflag & ECHO)
		(void) ldterm_echo(c, wrq, ebsize, tp);
	else {
		/*
		 * Echo NL when ECHO turned off, if ECHONL flag is
		 * set.
		 */
		if (c == '\n' && (tp->t_modes.c_lflag & ECHONL))
			ldterm_outchar(c, wrq, ebsize, tp);
	}

out:

	return (bpt);
}


static int
ldterm_unget(ldtermstd_state_t *tp)
{
	mblk_t *bpt;

	if ((bpt = tp->t_endmsg) == NULL)
		return (-1);	/* no buffers */
	if (bpt->b_rptr == bpt->b_wptr)
		return (-1);	/* zero-length record */
	tp->t_msglen--;		/* one fewer character */
	return (*--bpt->b_wptr);
}


static void
ldterm_trim(ldtermstd_state_t *tp)
{
	mblk_t *bpt;
	mblk_t *bp;

	ASSERT(tp->t_endmsg);
	bpt = tp->t_endmsg;

	if (bpt->b_rptr == bpt->b_wptr) {
		/*
		 * This mblk is now empty. Find the previous mblk;
		 * throw this one away, unless it's the first one.
		 */
		bp = tp->t_message;
		if (bp != bpt) {
			while (bp->b_cont != bpt) {
				ASSERT(bp->b_cont);
				bp = bp->b_cont;
			}
			bp->b_cont = NULL;
			freeb(bpt);
			tp->t_endmsg = bp;	/* point to that mblk */
		}
	}
}


/*
 * Rubout one character from the current line being built for tp as
 * cleanly as possible.  q is the write queue for tp. Most of this
 * can't be applied to multi-byte processing.  We do our own thing
 * for that... See the "ldterm_eucerase" routine.  We never call
 * ldterm_rubout on a multi-byte or multi-column character.
 */
static void
ldterm_rubout(uchar_t c, queue_t *q, size_t ebsize, ldtermstd_state_t *tp)
{
	int tabcols;
	static unsigned char crtrubout[] = "\b \b\b \b";
#define	RUBOUT1	&crtrubout[3]	/* rub out one position */
#define	RUBOUT2	&crtrubout[0]	/* rub out two positions */

	if (!(tp->t_modes.c_lflag & ECHO))
		return;
	if (tp->t_modes.c_lflag & ECHOE) {
		/*
		 * "CRT rubout"; try erasing it from the screen.
		 */
		if (tp->t_rocount == 0) {
			/*
			 * After the character being erased was
			 * echoed, some data was written to the
			 * terminal; we can't erase it cleanly, so we
			 * just reprint the whole line as if the user
			 * had typed the reprint character.
			 */
			ldterm_reprint(q, ebsize, tp);
			return;
		} else {
			/*
			 * XXX what about escaped characters?
			 */
			switch (typetab[c]) {

			case ORDINARY:
				if ((tp->t_modes.c_lflag & XCASE) &&
				    omaptab[c])
					ldterm_outstring(RUBOUT1, 3, q, ebsize,
					    tp);
				ldterm_outstring(RUBOUT1, 3, q, ebsize, tp);
				break;

			case VTAB:
			case BACKSPACE:
			case CONTROL:
			case RETURN:
			case NEWLINE:
				if ((tp->t_modes.c_lflag & ECHOCTL) &&
				    (tp->t_modes.c_lflag & IEXTEN))
					ldterm_outstring(RUBOUT2, 6, q, ebsize,
					    tp);
				break;

			case TAB:
				if (tp->t_rocount < tp->t_msglen) {
					/*
					 * While the tab being erased was
					 * expanded, some data was written
					 * to the terminal; we can't erase
					 * it cleanly, so we just reprint
					 * the whole line as if the user
					 * had typed the reprint character.
					 */
					ldterm_reprint(q, ebsize, tp);
					return;
				}
				tabcols = ldterm_tabcols(tp);
				while (--tabcols >= 0)
					ldterm_outchar('\b', q, ebsize, tp);
				break;
			}
		}
	} else if ((tp->t_modes.c_lflag & ECHOPRT) &&
	    (tp->t_modes.c_lflag & IEXTEN)) {
		/*
		 * "Printing rubout"; echo it between \ and /.
		 */
		if (!(tp->t_state & TS_ERASE)) {
			ldterm_outchar('\\', q, ebsize, tp);
			tp->t_state |= TS_ERASE;
		}
		(void) ldterm_echo(c, q, ebsize, tp);
	} else
		(void) ldterm_echo(tp->t_modes.c_cc[VERASE], q, ebsize, tp);
	tp->t_rocount--;	/* we "unechoed" this character */
}


/*
 * Find the number of characters the tab we just deleted took up by
 * zipping through the current line and recomputing the column
 * number.
 */
static int
ldterm_tabcols(ldtermstd_state_t *tp)
{
	int col;
	int i;
	mblk_t *bp;
	unsigned char *readp, *endp;
	unsigned char c;
	uchar_t *startp;
	char errflg;
	uchar_t u8[LDTERM_CS_MAX_BYTE_LENGTH];

	col = tp->t_rocol;
	/*
	 * If we're doing multi-byte stuff, zip through the list of
	 * widths to figure out where we are (we've kept track in most
	 * cases).
	 */
	if (tp->t_state & TS_MEUC) {
		ASSERT(tp->t_eucp_mp);
		bp = tp->t_message;
		startp = bp->b_datap->db_base;
		readp = tp->t_eucp_mp->b_rptr;
		endp = tp->t_eucp;
		errflg = (char)0;
		while (readp < endp) {
			switch (*readp) {
			case EUC_TWIDTH:	/* it's a tab */
				col |= 07;	/* bump up */
				col++;
				break;
			case EUC_BSWIDTH:	/* backspace */
				if (col)
					col--;
				break;
			case EUC_NLWIDTH:	/* newline */
				if (tp->t_modes.c_oflag & ONLRET)
					col = 0;
				break;
			case EUC_CRWIDTH:	/* return */
				col = 0;
				break;
			case UNKNOWN_WIDTH:	/* UTF-8 unknown width */
				if (tp->t_csdata.codeset_type !=
				    LDTERM_CS_TYPE_UTF8 || errflg) {
					*readp = 1;
					col++;
					break;
				}
				/*
				 * Collect the current UTF-8 character bytes
				 * from (possibly multiple) data buffers so
				 * that we can figure out the display width.
				 */
				u8[0] = *startp;
				for (i = 1; (i < LDTERM_CS_MAX_BYTE_LENGTH) &&
				    (*(readp + i) == 0); i++) {
					startp++;
					if (startp >= bp->b_datap->db_lim) {
						if (bp->b_cont) {
							bp = bp->b_cont;
							startp =
							    bp->b_datap->
							    db_base;
						} else {
							*readp = 1;
							col++;
							break;
						}
					}
					u8[i] = *startp;
				}

				/* tp->t_eucp_mp contains wrong info?? */
				if (*readp == 1)
					break;

				*readp = ldterm_utf8_width(u8, i);

				col += *readp;
				readp += (i - 1);
				break;
			default:
				col += *readp;
				break;
			}
			++readp;
			++startp;
			if (startp >= bp->b_datap->db_lim) {
				if (bp->b_cont) {
					bp = bp->b_cont;
					startp = bp->b_datap->db_base;
				} else {
					/*
					 * This will happen only if
					 * tp->t_eucp_mp contains wrong
					 * display width info.
					 */
					errflg = (char)1;
					startp--;
				}
			}
		}
		goto eucout;	/* finished! */
	}
	bp = tp->t_message;
	do {
		readp = bp->b_rptr;
		while (readp < bp->b_wptr) {
			c = *readp++;
			if ((tp->t_modes.c_lflag & ECHOCTL) &&
			    (tp->t_modes.c_lflag & IEXTEN)) {
				if (c <= 037 && c != '\t' && c != '\n' ||
				    c == 0177) {
					col += 2;
					continue;
				}
			}
			/*
			 * Column position calculated here.
			 */
			switch (typetab[c]) {

				/*
				 * Ordinary characters; advance by
				 * one.
				 */
			case ORDINARY:
				col++;
				break;

				/*
				 * Non-printing characters; nothing
				 * happens.
				 */
			case CONTROL:
				break;

				/* Backspace */
			case BACKSPACE:
				if (col != 0)
					col--;
				break;

				/* Newline; column depends on flags. */
			case NEWLINE:
				if (tp->t_modes.c_oflag & ONLRET)
					col = 0;
				break;

				/* tab */
			case TAB:
				col |= 07;
				col++;
				break;

				/* vertical motion */
			case VTAB:
				break;

				/* carriage return */
			case RETURN:
				col = 0;
				break;
			}
		}
	} while ((bp = bp->b_cont) != NULL);	/* next block, if any */

	/*
	 * "col" is now the column number before the tab. "tp->t_col"
	 * is still the column number after the tab, since we haven't
	 * erased the tab yet. Thus "tp->t_col - col" is the number
	 * of positions the tab moved.
	 */
eucout:
	col = tp->t_col - col;
	if (col > 8)
		col = 8;	/* overflow screw */
	return (col);
}


/*
 * Erase a single character; We ONLY ONLY deal with ASCII or
 * single-column single-byte codeset character.  For multi-byte characters,
 * see "ldterm_csi_erase".
 */
static void
ldterm_erase(queue_t *q, size_t ebsize, ldtermstd_state_t *tp)
{
	int c;

	if ((c = ldterm_unget(tp)) != -1) {
		ldterm_rubout((unsigned char) c, q, ebsize, tp);
		ldterm_trim(tp);
		if (tp->t_state & TS_MEUC)
			--tp->t_eucp;
	}
}


/*
 * Erase an entire word, single-byte EUC only please.
 */
static void
ldterm_werase(queue_t *q, size_t ebsize, ldtermstd_state_t *tp)
{
	int c;

	/*
	 * Erase trailing white space, if any.
	 */
	while ((c = ldterm_unget(tp)) == ' ' || c == '\t') {
		ldterm_rubout((unsigned char) c, q, ebsize, tp);
		ldterm_trim(tp);
	}

	/*
	 * Erase non-white-space characters, if any.
	 */
	while (c != -1 && c != ' ' && c != '\t') {
		ldterm_rubout((unsigned char) c, q, ebsize, tp);
		ldterm_trim(tp);
		c = ldterm_unget(tp);
	}
	if (c != -1) {
		/*
		 * We removed one too many characters; put the last
		 * one back.
		 */
		tp->t_endmsg->b_wptr++;	/* put 'c' back */
		tp->t_msglen++;
	}
}


/*
 * ldterm_csi_werase - This is multi-byte equivalent of "word erase".
 * "Word erase" only makes sense in languages which space between words,
 * and it's presumptuous for us to attempt "word erase" when we don't
 * know anything about what's really going on.  It makes no sense for
 * many languages, as the criteria for defining words and tokens may
 * be completely different.
 *
 * In the TS_MEUC case (which is how we got here), we define a token to
 * be space- or tab-delimited, and erase one of them.  It helps to
 * have this for command lines, but it's otherwise useless for text
 * editing applications; you need more sophistication than we can
 * provide here.
 */
static void
ldterm_csi_werase(queue_t *q, size_t ebsize, ldtermstd_state_t *tp)
{
	int c, i;
	int len;
	uchar_t *ip;
	uchar_t	u8[LDTERM_CS_MAX_BYTE_LENGTH];
	uchar_t	u8_2[LDTERM_CS_MAX_BYTE_LENGTH];

	/*
	 * ip points to the width of the actual bytes.  t_eucp points
	 * one byte beyond, where the next thing will be inserted.
	 */
	ip = tp->t_eucp - 1;
	/*
	 * Erase trailing white space, if any.
	 */
	while ((c = ldterm_unget(tp)) == ' ' || c == '\t') {
		tp->t_eucp--;
		ldterm_rubout((unsigned char) c, q, ebsize, tp);
		ldterm_trim(tp);
		--ip;
	}

	/*
	 * Erase non-white-space characters, if any.  The outer loop
	 * bops through each byte in the buffer. Multi-byte is removed, as
	 * is ASCII, one byte at a time. The inner loop (for) is only
	 * executed for first bytes of multi-byte.  The inner loop erases
	 * the number of columns required for the multi-byte char.  We check
	 * for ASCII first, and ldterm_rubout knows about ASCII.
	 */
	len = 0;
	while (c != -1 && c != ' ' && c != '\t') {
		tp->t_eucp--;
		if (len < LDTERM_CS_MAX_BYTE_LENGTH) {
			u8[len++] = (uchar_t)c;
		}
		/*
		 * Unlike EUC, except the leading byte, some bytes of
		 * a non-EUC multi-byte characters are in the ASCII code
		 * range, esp., 0x41 ~ 0x7a. Thus, we cannot simply check
		 * ISASCII().
		 * Checking the (*ip == 1 || *ip == 2 || *ip > UNKNOWN_WIDTH)
		 * will ensure that it is a single byte character (even though
		 * it is on display width not byte length) and can be further
		 * checked whether it is an ASCII character or not.
		 *
		 * When ECHOCTL is on and 'c' is an ASCII control character,
		 * *ip == 2 happens.
		 */
		if ((*ip == 1 || *ip == 2 || *ip > UNKNOWN_WIDTH) &&
		    ISASCII(c)) {
			ldterm_rubout((unsigned char) c, q, ebsize, tp);
			len = 0;
		} else if (*ip) {
			if (*ip == UNKNOWN_WIDTH) {
				if (tp->t_csdata.codeset_type ==
				    LDTERM_CS_TYPE_UTF8) {
					for (i = 0; i < len; i++)
						u8_2[i] = u8[len - i - 1];
					*ip = ldterm_utf8_width(u8_2, len);
				} else {
					*ip = 1;
				}
			}
			/*
			 * erase for number of columns required for
			 * this multi-byte character. Hopefully, matches
			 * ldterm_dispwidth!
			 */
			for (i = 0; i < (int)*ip; i++)
				ldterm_rubout(' ', q, ebsize, tp);
			len = 0;
		}
		ldterm_trim(tp);
		--ip;
		c = ldterm_unget(tp);
	}
	if (c != -1) {
		/*
		 * We removed one too many characters; put the last
		 * one back.
		 */
		tp->t_endmsg->b_wptr++;	/* put 'c' back */
		tp->t_msglen++;
	}
}


/*
 * Kill an entire line, erasing each character one-by-one (if ECHOKE
 * is set) or just echoing the kill character, followed by a newline
 * (if ECHOK is set).  Multi-byte processing is included here.
 */

static void
ldterm_kill(queue_t *q, size_t ebsize, ldtermstd_state_t *tp)
{
	int c, i;
	int len;
	uchar_t *ip;
	uchar_t u8[LDTERM_CS_MAX_BYTE_LENGTH];
	uchar_t u8_2[LDTERM_CS_MAX_BYTE_LENGTH];

	if ((tp->t_modes.c_lflag & ECHOKE) &&
	    (tp->t_modes.c_lflag & IEXTEN) &&
	    (tp->t_msglen == tp->t_rocount)) {
		if (tp->t_state & TS_MEUC) {
			ip = tp->t_eucp - 1;
			/*
			 * This loop similar to "ldterm_csi_werase" above.
			 */
			len = 0;
			while ((c = ldterm_unget(tp)) != (-1)) {
				tp->t_eucp--;
				if (len < LDTERM_CS_MAX_BYTE_LENGTH) {
					u8[len++] = (uchar_t)c;
				}
				if ((*ip == 1 || *ip == 2 ||
				    *ip > UNKNOWN_WIDTH) && ISASCII(c)) {
					ldterm_rubout((unsigned char) c, q,
					    ebsize, tp);
					len = 0;
				} else if (*ip) {
					if (*ip == UNKNOWN_WIDTH) {
						if (tp->t_csdata.codeset_type
						    == LDTERM_CS_TYPE_UTF8) {
							for (i = 0; i < len;
							    i++)
								u8_2[i] =
								    u8[len-i-1];
							*ip = ldterm_utf8_width(
							    u8_2, len);
						} else {
							*ip = 1;
						}
					}
					for (i = 0; i < (int)*ip; i++)
						ldterm_rubout(' ', q, ebsize,
						    tp);
					len = 0;
				}
				ldterm_trim(tp);
				--ip;
			}
		} else {
			while ((c = ldterm_unget(tp)) != -1) {
				ldterm_rubout((unsigned char) c, q, ebsize, tp);
				ldterm_trim(tp);
			}
		}
	} else {
		(void)