BSD 4.4 Lite Kernel Sources

1 files changed, 1923 insertions, 0 deletions

diff --git a/sys/kern/tty.c b/sys/kern/tty.c
new file mode 100644
index 0000000..6cc7be2
--- /dev/null
+++ b/sys/kern/tty.c
@@ -0,0 +1,1923 @@
+/*-
+ * Copyright (c) 1982, 1986, 1990, 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ * (c) UNIX System Laboratories, Inc.
+ * All or some portions of this file are derived from material licensed
+ * to the University of California by American Telephone and Telegraph
+ * Co. or Unix System Laboratories, Inc. and are reproduced herein with
+ * the permission of UNIX System Laboratories, Inc.
+ *
+ * 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.
+ *
+ *	@(#)tty.c	8.8 (Berkeley) 1/21/94
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/ioctl.h>
+#include <sys/proc.h>
+#define	TTYDEFCHARS
+#include <sys/tty.h>
+#undef	TTYDEFCHARS
+#include <sys/file.h>
+#include <sys/conf.h>
+#include <sys/dkstat.h>
+#include <sys/uio.h>
+#include <sys/kernel.h>
+#include <sys/vnode.h>
+#include <sys/syslog.h>
+
+#include <vm/vm.h>
+
+static int	proc_compare __P((struct proc *p1, struct proc *p2));
+static int	ttnread __P((struct tty *));
+static void	ttyblock __P((struct tty *tp));
+static void	ttyecho __P((int, struct tty *tp));
+static void	ttyrubo __P((struct tty *, int));
+
+/* Symbolic sleep message strings. */
+char ttclos[]	= "ttycls";
+char ttopen[]	= "ttyopn";
+char ttybg[]	= "ttybg";
+char ttybuf[]	= "ttybuf";
+char ttyin[]	= "ttyin";
+char ttyout[]	= "ttyout";
+
+/*
+ * Table with character classes and parity. The 8th bit indicates parity,
+ * the 7th bit indicates the character is an alphameric or underscore (for
+ * ALTWERASE), and the low 6 bits indicate delay type.  If the low 6 bits
+ * are 0 then the character needs no special processing on output; classes
+ * other than 0 might be translated or (not currently) require delays.
+ */
+#define	E	0x00	/* Even parity. */
+#define	O	0x80	/* Odd parity. */
+#define	PARITY(c)	(char_type[c] & O)
+
+#define	ALPHA	0x40	/* Alpha or underscore. */
+#define	ISALPHA(c)	(char_type[(c) & TTY_CHARMASK] & ALPHA)
+
+#define	CCLASSMASK	0x3f
+#define	CCLASS(c)	(char_type[c] & CCLASSMASK)
+
+#define	BS	BACKSPACE
+#define	CC	CONTROL
+#define	CR	RETURN
+#define	NA	ORDINARY | ALPHA
+#define	NL	NEWLINE
+#define	NO	ORDINARY
+#define	TB	TAB
+#define	VT	VTAB
+
+char const char_type[] = {
+	E|CC, O|CC, O|CC, E|CC, O|CC, E|CC, E|CC, O|CC,	/* nul - bel */
+	O|BS, E|TB, E|NL, O|CC, E|VT, O|CR, O|CC, E|CC, /* bs - si */
+	O|CC, E|CC, E|CC, O|CC, E|CC, O|CC, O|CC, E|CC, /* dle - etb */
+	E|CC, O|CC, O|CC, E|CC, O|CC, E|CC, E|CC, O|CC, /* can - us */
+	O|NO, E|NO, E|NO, O|NO, E|NO, O|NO, O|NO, E|NO, /* sp - ' */
+	E|NO, O|NO, O|NO, E|NO, O|NO, E|NO, E|NO, O|NO, /* ( - / */
+	E|NA, O|NA, O|NA, E|NA, O|NA, E|NA, E|NA, O|NA, /* 0 - 7 */
+	O|NA, E|NA, E|NO, O|NO, E|NO, O|NO, O|NO, E|NO, /* 8 - ? */
+	O|NO, E|NA, E|NA, O|NA, E|NA, O|NA, O|NA, E|NA, /* @ - G */
+	E|NA, O|NA, O|NA, E|NA, O|NA, E|NA, E|NA, O|NA, /* H - O */
+	E|NA, O|NA, O|NA, E|NA, O|NA, E|NA, E|NA, O|NA, /* P - W */
+	O|NA, E|NA, E|NA, O|NO, E|NO, O|NO, O|NO, O|NA, /* X - _ */
+	E|NO, O|NA, O|NA, E|NA, O|NA, E|NA, E|NA, O|NA, /* ` - g */
+	O|NA, E|NA, E|NA, O|NA, E|NA, O|NA, O|NA, E|NA, /* h - o */
+	O|NA, E|NA, E|NA, O|NA, E|NA, O|NA, O|NA, E|NA, /* p - w */
+	E|NA, O|NA, O|NA, E|NO, O|NO, E|NO, E|NO, O|CC, /* x - del */
+	/*
+	 * Meta chars; should be settable per character set;
+	 * for now, treat them all as normal characters.
+	 */
+	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
+	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
+	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
+	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
+	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
+	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
+	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
+	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
+	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
+	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
+	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
+	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
+	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
+	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
+	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
+	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
+};
+#undef	BS
+#undef	CC
+#undef	CR
+#undef	NA
+#undef	NL
+#undef	NO
+#undef	TB
+#undef	VT
+
+/* Macros to clear/set/test flags. */
+#define	SET(t, f)	(t) |= (f)
+#define	CLR(t, f)	(t) &= ~(f)
+#define	ISSET(t, f)	((t) & (f))
+
+/*
+ * Initial open of tty, or (re)entry to standard tty line discipline.
+ */
+int
+ttyopen(device, tp)
+	dev_t device;
+	register struct tty *tp;
+{
+	int s;
+
+	s = spltty();
+	tp->t_dev = device;
+	if (!ISSET(tp->t_state, TS_ISOPEN)) {
+		SET(tp->t_state, TS_ISOPEN);
+		bzero(&tp->t_winsize, sizeof(tp->t_winsize));
+	}
+	CLR(tp->t_state, TS_WOPEN);
+	splx(s);
+	return (0);
+}
+
+/*
+ * Handle close() on a tty line: flush and set to initial state,
+ * bumping generation number so that pending read/write calls
+ * can detect recycling of the tty.
+ */
+int
+ttyclose(tp)
+	register struct tty *tp;
+{
+	extern struct tty *constty;	/* Temporary virtual console. */
+
+	if (constty == tp)
+		constty = NULL;
+
+	ttyflush(tp, FREAD | FWRITE);
+
+	tp->t_gen++;
+	tp->t_pgrp = NULL;
+	tp->t_session = NULL;
+	tp->t_state = 0;
+	return (0);
+}
+
+#define	FLUSHQ(q) {							\
+	if ((q)->c_cc)							\
+		ndflush(q, (q)->c_cc);					\
+}
+
+/* Is 'c' a line delimiter ("break" character)? */
+#define	TTBREAKC(c)							\
+	((c) == '\n' || ((c) == cc[VEOF] ||				\
+	(c) == cc[VEOL] || (c) == cc[VEOL2]) && (c) != _POSIX_VDISABLE)
+
+
+/*
+ * Process input of a single character received on a tty.
+ */
+int
+ttyinput(c, tp)
+	register int c;
+	register struct tty *tp;
+{
+	register int iflag, lflag;
+	register u_char *cc;
+	int i, err;
+
+	/*
+	 * If input is pending take it first.
+	 */
+	lflag = tp->t_lflag;
+	if (ISSET(lflag, PENDIN))
+		ttypend(tp);
+	/*
+	 * Gather stats.
+	 */
+	if (ISSET(lflag, ICANON)) {
+		++tk_cancc;
+		++tp->t_cancc;
+	} else {
+		++tk_rawcc;
+		++tp->t_rawcc;
+	}
+	++tk_nin;
+
+	/* Handle exceptional conditions (break, parity, framing). */
+	cc = tp->t_cc;
+	iflag = tp->t_iflag;
+	if (err = (ISSET(c, TTY_ERRORMASK))) {
+		CLR(c, TTY_ERRORMASK);
+		if (ISSET(err, TTY_FE) && !c) {	/* Break. */
+			if (ISSET(iflag, IGNBRK))
+				goto endcase;
+			else if (ISSET(iflag, BRKINT) &&
+			    ISSET(lflag, ISIG) &&
+			    (cc[VINTR] != _POSIX_VDISABLE))
+				c = cc[VINTR];
+			else if (ISSET(iflag, PARMRK))
+				goto parmrk;
+		} else if (ISSET(err, TTY_PE) &&
+		    ISSET(iflag, INPCK) || ISSET(err, TTY_FE)) {
+			if (ISSET(iflag, IGNPAR))
+				goto endcase;
+			else if (ISSET(iflag, PARMRK)) {
+parmrk:				(void)putc(0377 | TTY_QUOTE, &tp->t_rawq);
+				(void)putc(0 | TTY_QUOTE, &tp->t_rawq);
+				(void)putc(c | TTY_QUOTE, &tp->t_rawq);
+				goto endcase;
+			} else
+				c = 0;
+		}
+	}
+	/*
+	 * In tandem mode, check high water mark.
+	 */
+	if (ISSET(iflag, IXOFF))
+		ttyblock(tp);
+	if (!ISSET(tp->t_state, TS_TYPEN) && ISSET(iflag, ISTRIP))
+		CLR(c, 0x80);
+	if (!ISSET(lflag, EXTPROC)) {
+		/*
+		 * Check for literal nexting very first
+		 */
+		if (ISSET(tp->t_state, TS_LNCH)) {
+			SET(c, TTY_QUOTE);
+			CLR(tp->t_state, TS_LNCH);
+		}
+		/*
+		 * Scan for special characters.  This code
+		 * is really just a big case statement with
+		 * non-constant cases.  The bottom of the
+		 * case statement is labeled ``endcase'', so goto
+		 * it after a case match, or similar.
+		 */
+
+		/*
+		 * Control chars which aren't controlled
+		 * by ICANON, ISIG, or IXON.
+		 */
+		if (ISSET(lflag, IEXTEN)) {
+			if (CCEQ(cc[VLNEXT], c)) {
+				if (ISSET(lflag, ECHO)) {
+					if (ISSET(lflag, ECHOE)) {
+						(void)ttyoutput('^', tp);
+						(void)ttyoutput('\b', tp);
+					} else
+						ttyecho(c, tp);
+				}
+				SET(tp->t_state, TS_LNCH);
+				goto endcase;
+			}
+			if (CCEQ(cc[VDISCARD], c)) {
+				if (ISSET(lflag, FLUSHO))
+					CLR(tp->t_lflag, FLUSHO);
+				else {
+					ttyflush(tp, FWRITE);
+					ttyecho(c, tp);
+					if (tp->t_rawq.c_cc + tp->t_canq.c_cc)
+						ttyretype(tp);
+					SET(tp->t_lflag, FLUSHO);
+				}
+				goto startoutput;
+			}
+		}
+		/*
+		 * Signals.
+		 */
+		if (ISSET(lflag, ISIG)) {
+			if (CCEQ(cc[VINTR], c) || CCEQ(cc[VQUIT], c)) {
+				if (!ISSET(lflag, NOFLSH))
+					ttyflush(tp, FREAD | FWRITE);
+				ttyecho(c, tp);
+				pgsignal(tp->t_pgrp,
+				    CCEQ(cc[VINTR], c) ? SIGINT : SIGQUIT, 1);
+				goto endcase;
+			}
+			if (CCEQ(cc[VSUSP], c)) {
+				if (!ISSET(lflag, NOFLSH))
+					ttyflush(tp, FREAD);
+				ttyecho(c, tp);
+				pgsignal(tp->t_pgrp, SIGTSTP, 1);
+				goto endcase;
+			}
+		}
+		/*
+		 * Handle start/stop characters.
+		 */
+		if (ISSET(iflag, IXON)) {
+			if (CCEQ(cc[VSTOP], c)) {
+				if (!ISSET(tp->t_state, TS_TTSTOP)) {
+					SET(tp->t_state, TS_TTSTOP);
+#ifdef sun4c						/* XXX */
+					(*tp->t_stop)(tp, 0);
+#else
+					(*cdevsw[major(tp->t_dev)].d_stop)(tp,
+					   0);
+#endif
+					return (0);
+				}
+				if (!CCEQ(cc[VSTART], c))
+					return (0);
+				/*
+				 * if VSTART == VSTOP then toggle
+				 */
+				goto endcase;
+			}
+			if (CCEQ(cc[VSTART], c))
+				goto restartoutput;
+		}
+		/*
+		 * IGNCR, ICRNL, & INLCR
+		 */
+		if (c == '\r') {
+			if (ISSET(iflag, IGNCR))
+				goto endcase;
+			else if (ISSET(iflag, ICRNL))
+				c = '\n';
+		} else if (c == '\n' && ISSET(iflag, INLCR))
+			c = '\r';
+	}
+	if (!ISSET(tp->t_lflag, EXTPROC) && ISSET(lflag, ICANON)) {
+		/*
+		 * From here on down canonical mode character
+		 * processing takes place.
+		 */
+		/*
+		 * erase (^H / ^?)
+		 */
+		if (CCEQ(cc[VERASE], c)) {
+			if (tp->t_rawq.c_cc)
+				ttyrub(unputc(&tp->t_rawq), tp);
+			goto endcase;
+		}
+		/*
+		 * kill (^U)
+		 */
+		if (CCEQ(cc[VKILL], c)) {
+			if (ISSET(lflag, ECHOKE) &&
+			    tp->t_rawq.c_cc == tp->t_rocount &&
+			    !ISSET(lflag, ECHOPRT))
+				while (tp->t_rawq.c_cc)
+					ttyrub(unputc(&tp->t_rawq), tp);
+			else {
+				ttyecho(c, tp);
+				if (ISSET(lflag, ECHOK) ||
+				    ISSET(lflag, ECHOKE))
+					ttyecho('\n', tp);
+				FLUSHQ(&tp->t_rawq);
+				tp->t_rocount = 0;
+			}
+			CLR(tp->t_state, TS_LOCAL);
+			goto endcase;
+		}
+		/*
+		 * word erase (^W)
+		 */
+		if (CCEQ(cc[VWERASE], c)) {
+			int alt = ISSET(lflag, ALTWERASE);
+			int ctype;
+
+			/*
+			 * erase whitespace
+			 */
+			while ((c = unputc(&tp->t_rawq)) == ' ' || c == '\t')
+				ttyrub(c, tp);
+			if (c == -1)
+				goto endcase;
+			/*
+			 * erase last char of word and remember the
+			 * next chars type (for ALTWERASE)
+			 */
+			ttyrub(c, tp);
+			c = unputc(&tp->t_rawq);
+			if (c == -1)
+				goto endcase;
+			if (c == ' ' || c == '\t') {
+				(void)putc(c, &tp->t_rawq);
+				goto endcase;
+			}
+			ctype = ISALPHA(c);
+			/*
+			 * erase rest of word
+			 */
+			do {
+				ttyrub(c, tp);
+				c = unputc(&tp->t_rawq);
+				if (c == -1)
+					goto endcase;
+			} while (c != ' ' && c != '\t' &&
+			    (alt == 0 || ISALPHA(c) == ctype));
+			(void)putc(c, &tp->t_rawq);
+			goto endcase;
+		}
+		/*
+		 * reprint line (^R)
+		 */
+		if (CCEQ(cc[VREPRINT], c)) {
+			ttyretype(tp);
+			goto endcase;
+		}
+		/*
+		 * ^T - kernel info and generate SIGINFO
+		 */
+		if (CCEQ(cc[VSTATUS], c)) {
+			if (ISSET(lflag, ISIG))
+				pgsignal(tp->t_pgrp, SIGINFO, 1);
+			if (!ISSET(lflag, NOKERNINFO))
+				ttyinfo(tp);
+			goto endcase;
+		}
+	}
+	/*
+	 * Check for input buffer overflow
+	 */
+	if (tp->t_rawq.c_cc + tp->t_canq.c_cc >= TTYHOG) {
+		if (ISSET(iflag, IMAXBEL)) {
+			if (tp->t_outq.c_cc < tp->t_hiwat)
+				(void)ttyoutput(CTRL('g'), tp);
+		} else
+			ttyflush(tp, FREAD | FWRITE);
+		goto endcase;
+	}
+	/*
+	 * Put data char in q for user and
+	 * wakeup on seeing a line delimiter.
+	 */
+	if (putc(c, &tp->t_rawq) >= 0) {
+		if (!ISSET(lflag, ICANON)) {
+			ttwakeup(tp);
+			ttyecho(c, tp);
+			goto endcase;
+		}
+		if (TTBREAKC(c)) {
+			tp->t_rocount = 0;
+			catq(&tp->t_rawq, &tp->t_canq);
+			ttwakeup(tp);
+		} else if (tp->t_rocount++ == 0)
+			tp->t_rocol = tp->t_column;
+		if (ISSET(tp->t_state, TS_ERASE)) {
+			/*
+			 * end of prterase \.../
+			 */
+			CLR(tp->t_state, TS_ERASE);
+			(void)ttyoutput('/', tp);
+		}
+		i = tp->t_column;
+		ttyecho(c, tp);
+		if (CCEQ(cc[VEOF], c) && ISSET(lflag, ECHO)) {
+			/*
+			 * Place the cursor over the '^' of the ^D.
+			 */
+			i = min(2, tp->t_column - i);
+			while (i > 0) {
+				(void)ttyoutput('\b', tp);
+				i--;
+			}
+		}
+	}
+endcase:
+	/*
+	 * IXANY means allow any character to restart output.
+	 */
+	if (ISSET(tp->t_state, TS_TTSTOP) &&
+	    !ISSET(iflag, IXANY) && cc[VSTART] != cc[VSTOP])
+		return (0);
+restartoutput:
+	CLR(tp->t_lflag, FLUSHO);
+	CLR(tp->t_state, TS_TTSTOP);
+startoutput:
+	return (ttstart(tp));
+}
+
+/*
+ * Output a single character on a tty, doing output processing
+ * as needed (expanding tabs, newline processing, etc.).
+ * Returns < 0 if succeeds, otherwise returns char to resend.
+ * Must be recursive.
+ */
+int
+ttyoutput(c, tp)
+	register int c;
+	register struct tty *tp;
+{
+	register long oflag;
+	register int col, s;
+
+	oflag = tp->t_oflag;
+	if (!ISSET(oflag, OPOST)) {
+		if (ISSET(tp->t_lflag, FLUSHO))
+			return (-1);
+		if (putc(c, &tp->t_outq))
+			return (c);
+		tk_nout++;
+		tp->t_outcc++;
+		return (-1);
+	}
+	/*
+	 * Do tab expansion if OXTABS is set.  Special case if we external
+	 * processing, we don't do the tab expansion because we'll probably
+	 * get it wrong.  If tab expansion needs to be done, let it happen
+	 * externally.
+	 */
+	CLR(c, ~TTY_CHARMASK);
+	if (c == '\t' &&
+	    ISSET(oflag, OXTABS) && !ISSET(tp->t_lflag, EXTPROC)) {
+		c = 8 - (tp->t_column & 7);
+		if (!ISSET(tp->t_lflag, FLUSHO)) {
+			s = spltty();		/* Don't interrupt tabs. */
+			c -= b_to_q("        ", c, &tp->t_outq);
+			tk_nout += c;
+			tp->t_outcc += c;
+			splx(s);
+		}
+		tp->t_column += c;
+		return (c ? -1 : '\t');
+	}
+	if (c == CEOT && ISSET(oflag, ONOEOT))
+		return (-1);
+
+	/*
+	 * Newline translation: if ONLCR is set,
+	 * translate newline into "\r\n".
+	 */
+	if (c == '\n' && ISSET(tp->t_oflag, ONLCR)) {
+		tk_nout++;
+		tp->t_outcc++;
+		if (putc('\r', &tp->t_outq))
+			return (c);
+	}
+	tk_nout++;
+	tp->t_outcc++;
+	if (!ISSET(tp->t_lflag, FLUSHO) && putc(c, &tp->t_outq))
+		return (c);
+
+	col = tp->t_column;
+	switch (CCLASS(c)) {
+	case BACKSPACE:
+		if (col > 0)
+			--col;
+		break;
+	case CONTROL:
+		break;
+	case NEWLINE:
+	case RETURN:
+		col = 0;
+		break;
+	case ORDINARY:
+		++col;
+		break;
+	case TAB:
+		col = (col + 8) & ~7;
+		break;
+	}
+	tp->t_column = col;
+	return (-1);
+}
+
+/*
+ * Ioctls for all tty devices.  Called after line-discipline specific ioctl
+ * has been called to do discipline-specific functions and/or reject any
+ * of these ioctl commands.
+ */
+/* ARGSUSED */
+int
+ttioctl(tp, cmd, data, flag)
+	register struct tty *tp;
+	int cmd, flag;
+	void *data;
+{
+	extern struct tty *constty;	/* Temporary virtual console. */
+	extern int nlinesw;
+	register struct proc *p;
+	int s, error;
+
+	p = curproc;			/* XXX */
+
+	/* If the ioctl involves modification, hang if in the background. */
+	switch (cmd) {
+	case  TIOCFLUSH:
+	case  TIOCSETA:
+	case  TIOCSETD:
+	case  TIOCSETAF:
+	case  TIOCSETAW:
+#ifdef notdef
+	case  TIOCSPGRP:
+#endif
+	case  TIOCSTI:
+	case  TIOCSWINSZ:
+#if defined(COMPAT_43) || defined(COMPAT_SUNOS)
+	case  TIOCLBIC:
+	case  TIOCLBIS:
+	case  TIOCLSET:
+	case  TIOCSETC:
+	case OTIOCSETD:
+	case  TIOCSETN:
+	case  TIOCSETP:
+	case  TIOCSLTC:
+#endif
+		while (isbackground(curproc, tp) &&
+		    p->p_pgrp->pg_jobc && (p->p_flag & P_PPWAIT) == 0 &&
+		    (p->p_sigignore & sigmask(SIGTTOU)) == 0 &&
+		    (p->p_sigmask & sigmask(SIGTTOU)) == 0) {
+			pgsignal(p->p_pgrp, SIGTTOU, 1);
+			if (error = ttysleep(tp,
+			    &lbolt, TTOPRI | PCATCH, ttybg, 0))
+				return (error);
+		}
+		break;
+	}
+
+	switch (cmd) {			/* Process the ioctl. */
+	case FIOASYNC:			/* set/clear async i/o */
+		s = spltty();
+		if (*(int *)data)
+			SET(tp->t_state, TS_ASYNC);
+		else
+			CLR(tp->t_state, TS_ASYNC);
+		splx(s);
+		break;
+	case FIONBIO:			/* set/clear non-blocking i/o */
+		break;			/* XXX: delete. */
+	case FIONREAD:			/* get # bytes to read */
+		*(int *)data = ttnread(tp);
+		break;
+	case TIOCEXCL:			/* set exclusive use of tty */
+		s = spltty();
+		SET(tp->t_state, TS_XCLUDE);
+		splx(s);
+		break;
+	case TIOCFLUSH: {		/* flush buffers */
+		register int flags = *(int *)data;
+
+		if (flags == 0)
+			flags = FREAD | FWRITE;
+		else
+			flags &= FREAD | FWRITE;
+		ttyflush(tp, flags);
+		break;
+	}
+	case TIOCCONS:			/* become virtual console */
+		if (*(int *)data) {
+			if (constty && constty != tp &&
+			    ISSET(constty->t_state, TS_CARR_ON | TS_ISOPEN) ==
+			    (TS_CARR_ON | TS_ISOPEN))
+				return (EBUSY);
+#ifndef	UCONSOLE
+			if (error = suser(p->p_ucred, &p->p_acflag))
+				return (error);
+#endif
+			constty = tp;
+		} else if (tp == constty)
+			constty = NULL;
+		break;
+	case TIOCDRAIN:			/* wait till output drained */
+		if (error = ttywait(tp))
+			return (error);
+		break;
+	case TIOCGETA: {		/* get termios struct */
+		struct termios *t = (struct termios *)data;
+
+		bcopy(&tp->t_termios, t, sizeof(struct termios));
+		break;
+	}
+	case TIOCGETD:			/* get line discipline */
+		*(int *)data = tp->t_line;
+		break;
+	case TIOCGWINSZ:		/* get window size */
+		*(struct winsize *)data = tp->t_winsize;
+		break;
+	case TIOCGPGRP:			/* get pgrp of tty */
+		if (!isctty(p, tp))
+			return (ENOTTY);
+		*(int *)data = tp->t_pgrp ? tp->t_pgrp->pg_id : NO_PID;
+		break;
+#ifdef TIOCHPCL
+	case TIOCHPCL:			/* hang up on last close */
+		s = spltty();
+		SET(tp->t_cflag, HUPCL);
+		splx(s);
+		break;
+#endif
+	case TIOCNXCL:			/* reset exclusive use of tty */
+		s = spltty();
+		CLR(tp->t_state, TS_XCLUDE);
+		splx(s);
+		break;
+	case TIOCOUTQ:			/* output queue size */
+		*(int *)data = tp->t_outq.c_cc;
+		break;
+	case TIOCSETA:			/* set termios struct */
+	case TIOCSETAW:			/* drain output, set */
+	case TIOCSETAF: {		/* drn out, fls in, set */
+		register struct termios *t = (struct termios *)data;
+
+		s = spltty();
+		if (cmd == TIOCSETAW || cmd == TIOCSETAF) {
+			if (error = ttywait(tp)) {
+				splx(s);
+				return (error);
+			}
+			if (cmd == TIOCSETAF)
+				ttyflush(tp, FREAD);
+		}
+		if (!ISSET(t->c_cflag, CIGNORE)) {
+			/*
+			 * Set device hardware.
+			 */
+			if (tp->t_param && (error = (*tp->t_param)(tp, t))) {
+				splx(s);
+				return (error);
+			} else {
+				if (!ISSET(tp->t_state, TS_CARR_ON) &&
+				    ISSET(tp->t_cflag, CLOCAL) &&
+				    !ISSET(t->c_cflag, CLOCAL)) {
+					CLR(tp->t_state, TS_ISOPEN);
+					SET(tp->t_state, TS_WOPEN);
+					ttwakeup(tp);
+				}
+				tp->t_cflag = t->c_cflag;
+				tp->t_ispeed = t->c_ispeed;
+				tp->t_ospeed = t->c_ospeed;
+			}
+			ttsetwater(tp);
+		}
+		if (cmd != TIOCSETAF) {
+			if (ISSET(t->c_lflag, ICANON) !=
+			    ISSET(tp->t_lflag, ICANON))
+				if (ISSET(t->c_lflag, ICANON)) {
+					SET(tp->t_lflag, PENDIN);
+					ttwakeup(tp);
+				} else {
+					struct clist tq;
+
+					catq(&tp->t_rawq, &tp->t_canq);
+					tq = tp->t_rawq;
+					tp->t_rawq = tp->t_canq;
+					tp->t_canq = tq;
+					CLR(tp->t_lflag, PENDIN);
+				}
+		}
+		tp->t_iflag = t->c_iflag;
+		tp->t_oflag = t->c_oflag;
+		/*
+		 * Make the EXTPROC bit read only.
+		 */
+		if (ISSET(tp->t_lflag, EXTPROC))
+			SET(t->c_lflag, EXTPROC);
+		else
+			CLR(t->c_lflag, EXTPROC);
+		tp->t_lflag = t->c_lflag | ISSET(tp->t_lflag, PENDIN);
+		bcopy(t->c_cc, tp->t_cc, sizeof(t->c_cc));
+		splx(s);
+		break;
+	}
+	case TIOCSETD: {		/* set line discipline */
+		register int t = *(int *)data;
+		dev_t device = tp->t_dev;
+
+		if ((u_int)t >= nlinesw)
+			return (ENXIO);
+		if (t != tp->t_line) {
+			s = spltty();
+			(*linesw[tp->t_line].l_close)(tp, flag);
+			error = (*linesw[t].l_open)(device, tp);
+			if (error) {
+				(void)(*linesw[tp->t_line].l_open)(device, tp);
+				splx(s);
+				return (error);
+			}
+			tp->t_line = t;
+			splx(s);
+		}
+		break;
+	}
+	case TIOCSTART:			/* start output, like ^Q */
+		s = spltty();
+		if (ISSET(tp->t_state, TS_TTSTOP) ||
+		    ISSET(tp->t_lflag, FLUSHO)) {
+			CLR(tp->t_lflag, FLUSHO);
+			CLR(tp->t_state, TS_TTSTOP);
+			ttstart(tp);
+		}
+		splx(s);
+		break;
+	case TIOCSTI:			/* simulate terminal input */
+		if (p->p_ucred->cr_uid && (flag & FREAD) == 0)
+			return (EPERM);
+		if (p->p_ucred->cr_uid && !isctty(p, tp))
+			return (EACCES);
+		(*linesw[tp->t_line].l_rint)(*(u_char *)data, tp);
+		break;
+	case TIOCSTOP:			/* stop output, like ^S */
+		s = spltty();
+		if (!ISSET(tp->t_state, TS_TTSTOP)) {
+			SET(tp->t_state, TS_TTSTOP);
+#ifdef sun4c				/* XXX */
+			(*tp->t_stop)(tp, 0);
+#else
+			(*cdevsw[major(tp->t_dev)].d_stop)(tp, 0);
+#endif
+		}
+		splx(s);
+		break;
+	case TIOCSCTTY:			/* become controlling tty */
+		/* Session ctty vnode pointer set in vnode layer. */
+		if (!SESS_LEADER(p) ||
+		    (p->p_session->s_ttyvp || tp->t_session) &&
+		    (tp->t_session != p->p_session))
+			return (EPERM);
+		tp->t_session = p->p_session;
+		tp->t_pgrp = p->p_pgrp;
+		p->p_session->s_ttyp = tp;
+		p->p_flag |= P_CONTROLT;
+		break;
+	case TIOCSPGRP: {		/* set pgrp of tty */
+		register struct pgrp *pgrp = pgfind(*(int *)data);
+
+		if (!isctty(p, tp))
+			return (ENOTTY);
+		else if (pgrp == NULL || pgrp->pg_session != p->p_session)
+			return (EPERM);
+		tp->t_pgrp = pgrp;
+		break;
+	}
+	case TIOCSWINSZ:		/* set window size */
+		if (bcmp((caddr_t)&tp->t_winsize, data,
+		    sizeof (struct winsize))) {
+			tp->t_winsize = *(struct winsize *)data;
+			pgsignal(tp->t_pgrp, SIGWINCH, 1);
+		}
+		break;
+	default:
+#if defined(COMPAT_43) || defined(COMPAT_SUNOS)
+		return (ttcompat(tp, cmd, data, flag));
+#else
+		return (-1);
+#endif
+	}
+	return (0);
+}
+
+int
+ttselect(device, rw, p)
+	dev_t device;
+	int rw;
+	struct proc *p;
+{
+	register struct tty *tp;
+	int nread, s;
+
+	tp = &cdevsw[major(device)].d_ttys[minor(device)];
+
+	s = spltty();
+	switch (rw) {
+	case FREAD:
+		nread = ttnread(tp);
+		if (nread > 0 || !ISSET(tp->t_cflag, CLOCAL) &&
+		    !ISSET(tp->t_state, TS_CARR_ON))
+			goto win;
+		selrecord(p, &tp->t_rsel);
+		break;
+	case FWRITE:
+		if (tp->t_outq.c_cc <= tp->t_lowat) {
+win:			splx(s);
+			return (1);
+		}
+		selrecord(p, &tp->t_wsel);
+		break;
+	}
+	splx(s);
+	return (0);
+}
+
+static int
+ttnread(tp)
+	struct tty *tp;
+{
+	int nread;
+
+	if (ISSET(tp->t_lflag, PENDIN))
+		ttypend(tp);
+	nread = tp->t_canq.c_cc;
+	if (!ISSET(tp->t_lflag, ICANON))
+		nread += tp->t_rawq.c_cc;
+	return (nread);
+}
+
+/*
+ * Wait for output to drain.
+ */
+int
+ttywait(tp)
+	register struct tty *tp;
+{
+	int error, s;
+
+	error = 0;
+	s = spltty();
+	while ((tp->t_outq.c_cc || ISSET(tp->t_state, TS_BUSY)) &&
+	    (ISSET(tp->t_state, TS_CARR_ON) || ISSET(tp->t_cflag, CLOCAL))
+	    && tp->t_oproc) {
+		(*tp->t_oproc)(tp);
+		SET(tp->t_state, TS_ASLEEP);
+		if (error = ttysleep(tp,
+		    &tp->t_outq, TTOPRI | PCATCH, ttyout, 0))
+			break;
+	}
+	splx(s);
+	return (error);
+}
+
+/*
+ * Flush if successfully wait.
+ */
+int
+ttywflush(tp)
+	struct tty *tp;
+{
+	int error;
+
+	if ((error = ttywait(tp)) == 0)
+		ttyflush(tp, FREAD);
+	return (error);
+}
+
+/*
+ * Flush tty read and/or write queues, notifying anyone waiting.
+ */
+void
+ttyflush(tp, rw)
+	register struct tty *tp;
+	int rw;
+{
+	register int s;
+
+	s = spltty();
+	if (rw & FREAD) {
+		FLUSHQ(&tp->t_canq);
+		FLUSHQ(&tp->t_rawq);
+		tp->t_rocount = 0;
+		tp->t_rocol = 0;
+		CLR(tp->t_state, TS_LOCAL);
+		ttwakeup(tp);
+	}
+	if (rw & FWRITE) {
+		CLR(tp->t_state, TS_TTSTOP);
+#ifdef sun4c						/* XXX */
+		(*tp->t_stop)(tp, rw);
+#else
+		(*cdevsw[major(tp->t_dev)].d_stop)(tp, rw);
+#endif
+		FLUSHQ(&tp->t_outq);
+		wakeup((caddr_t)&tp->t_outq);
+		selwakeup(&tp->t_wsel);
+	}
+	splx(s);
+}
+
+/*
+ * Copy in the default termios characters.
+ */
+void
+ttychars(tp)
+	struct tty *tp;
+{
+
+	bcopy(ttydefchars, tp->t_cc, sizeof(ttydefchars));
+}
+
+/*
+ * Send stop character on input overflow.
+ */
+static void
+ttyblock(tp)
+	register struct tty *tp;
+{
+	register int total;
+
+	total = tp->t_rawq.c_cc + tp->t_canq.c_cc;
+	if (tp->t_rawq.c_cc > TTYHOG) {
+		ttyflush(tp, FREAD | FWRITE);
+		CLR(tp->t_state, TS_TBLOCK);
+	}
+	/*
+	 * Block further input iff: current input > threshold
+	 * AND input is available to user program.
+	 */
+	if (total >= TTYHOG / 2 &&
+	    !ISSET(tp->t_state, TS_TBLOCK) &&
+	    !ISSET(tp->t_lflag, ICANON) || tp->t_canq.c_cc > 0 &&
+	    tp->t_cc[VSTOP] != _POSIX_VDISABLE) {
+		if (putc(tp->t_cc[VSTOP], &tp->t_outq) == 0) {
+			SET(tp->t_state, TS_TBLOCK);
+			ttstart(tp);
+		}
+	}
+}
+
+void
+ttrstrt(tp_arg)
+	void *tp_arg;
+{
+	struct tty *tp;
+	int s;
+
+#ifdef DIAGNOSTIC
+	if (tp_arg == NULL)
+		panic("ttrstrt");
+#endif
+	tp = tp_arg;
+	s = spltty();
+
+	CLR(tp->t_state, TS_TIMEOUT);
+	ttstart(tp);
+
+	splx(s);
+}
+
+int
+ttstart(tp)
+	struct tty *tp;
+{
+
+	if (tp->t_oproc != NULL)	/* XXX: Kludge for pty. */
+		(*tp->t_oproc)(tp);
+	return (0);
+}
+
+/*
+ * "close" a line discipline
+ */
+int
+ttylclose(tp, flag)
+	struct tty *tp;
+	int flag;
+{
+
+	if (flag & IO_NDELAY)
+		ttyflush(tp, FREAD | FWRITE);
+	else
+		ttywflush(tp);
+	return (0);
+}
+
+/*
+ * Handle modem control transition on a tty.
+ * Flag indicates new state of carrier.
+ * Returns 0 if the line should be turned off, otherwise 1.
+ */
+int
+ttymodem(tp, flag)
+	register struct tty *tp;
+	int flag;
+{
+
+	if (!ISSET(tp->t_state, TS_WOPEN) && ISSET(tp->t_cflag, MDMBUF)) {
+		/*
+		 * MDMBUF: do flow control according to carrier flag
+		 */
+		if (flag) {
+			CLR(tp->t_state, TS_TTSTOP);
+			ttstart(tp);
+		} else if (!ISSET(tp->t_state, TS_TTSTOP)) {
+			SET(tp->t_state, TS_TTSTOP);
+#ifdef sun4c						/* XXX */
+			(*tp->t_stop)(tp, 0);
+#else
+			(*cdevsw[major(tp->t_dev)].d_stop)(tp, 0);
+#endif
+		}
+	} else if (flag == 0) {
+		/*
+		 * Lost carrier.
+		 */
+		CLR(tp->t_state, TS_CARR_ON);
+		if (ISSET(tp->t_state, TS_ISOPEN) &&
+		    !ISSET(tp->t_cflag, CLOCAL)) {
+			if (tp->t_session && tp->t_session->s_leader)
+				psignal(tp->t_session->s_leader, SIGHUP);
+			ttyflush(tp, FREAD | FWRITE);
+			return (0);
+		}
+	} else {
+		/*
+		 * Carrier now on.
+		 */
+		SET(tp->t_state, TS_CARR_ON);
+		ttwakeup(tp);
+	}
+	return (1);
+}
+
+/*
+ * Default modem control routine (for other line disciplines).
+ * Return argument flag, to turn off device on carrier drop.
+ */
+int
+nullmodem(tp, flag)
+	register struct tty *tp;
+	int flag;
+{
+
+	if (flag)
+		SET(tp->t_state, TS_CARR_ON);
+	else {
+		CLR(tp->t_state, TS_CARR_ON);
+		if (!ISSET(tp->t_cflag, CLOCAL)) {
+			if (tp->t_session && tp->t_session->s_leader)
+				psignal(tp->t_session->s_leader, SIGHUP);
+			return (0);
+		}
+	}
+	return (1);
+}
+
+/*
+ * Reinput pending characters after state switch
+ * call at spltty().
+ */
+void
+ttypend(tp)
+	register struct tty *tp;
+{
+	struct clist tq;
+	register c;
+
+	CLR(tp->t_lflag, PENDIN);
+	SET(tp->t_state, TS_TYPEN);
+	tq = tp->t_rawq;
+	tp->t_rawq.c_cc = 0;
+	tp->t_rawq.c_cf = tp->t_rawq.c_cl = 0;
+	while ((c = getc(&tq)) >= 0)
+		ttyinput(c, tp);
+	CLR(tp->t_state, TS_TYPEN);
+}
+
+/*
+ * Process a read call on a tty device.
+ */
+int
+ttread(tp, uio, flag)
+	register struct tty *tp;
+	struct uio *uio;
+	int flag;
+{
+	register struct clist *qp;
+	register int c;
+	register long lflag;
+	register u_char *cc = tp->t_cc;
+	register struct proc *p = curproc;
+	int s, first, error = 0;
+
+loop:	lflag = tp->t_lflag;
+	s = spltty();
+	/*
+	 * take pending input first
+	 */
+	if (ISSET(lflag, PENDIN))
+		ttypend(tp);
+	splx(s);
+
+	/*
+	 * Hang process if it's in the background.
+	 */
+	if (isbackground(p, tp)) {
+		if ((p->p_sigignore & sigmask(SIGTTIN)) ||
+		   (p->p_sigmask & sigmask(SIGTTIN)) ||
+		    p->p_flag & P_PPWAIT || p->p_pgrp->pg_jobc == 0)
+			return (EIO);
+		pgsignal(p->p_pgrp, SIGTTIN, 1);
+		if (error = ttysleep(tp, &lbolt, TTIPRI | PCATCH, ttybg, 0))
+			return (error);
+		goto loop;
+	}
+
+	/*
+	 * If canonical, use the canonical queue,
+	 * else use the raw queue.
+	 *
+	 * (should get rid of clists...)
+	 */
+	qp = ISSET(lflag, ICANON) ? &tp->t_canq : &tp->t_rawq;
+
+	/*
+	 * If there is no input, sleep on rawq
+	 * awaiting hardware receipt and notification.
+	 * If we have data, we don't need to check for carrier.
+	 */
+	s = spltty();
+	if (qp->c_cc <= 0) {
+		int carrier;
+
+		carrier = ISSET(tp->t_state, TS_CARR_ON) ||
+		    ISSET(tp->t_cflag, CLOCAL);
+		if (!carrier && ISSET(tp->t_state, TS_ISOPEN)) {
+			splx(s);
+			return (0);	/* EOF */
+		}
+		if (flag & IO_NDELAY) {
+			splx(s);
+			return (EWOULDBLOCK);
+		}
+		error = ttysleep(tp, &tp->t_rawq, TTIPRI | PCATCH,
+		    carrier ? ttyin : ttopen, 0);
+		splx(s);
+		if (error)
+			return (error);
+		goto loop;
+	}
+	splx(s);
+
+	/*
+	 * Input present, check for input mapping and processing.
+	 */
+	first = 1;
+	while ((c = getc(qp)) >= 0) {
+		/*
+		 * delayed suspend (^Y)
+		 */
+		if (CCEQ(cc[VDSUSP], c) && ISSET(lflag, ISIG)) {
+			pgsignal(tp->t_pgrp, SIGTSTP, 1);
+			if (first) {
+				if (error = ttysleep(tp,
+				    &lbolt, TTIPRI | PCATCH, ttybg, 0))
+					break;
+				goto loop;
+			}
+			break;
+		}
+		/*
+		 * Interpret EOF only in canonical mode.
+		 */
+		if (CCEQ(cc[VEOF], c) && ISSET(lflag, ICANON))
+			break;
+		/*
+		 * Give user character.
+		 */
+ 		error = ureadc(c, uio);
+		if (error)
+			break;
+ 		if (uio->uio_resid == 0)
+			break;
+		/*
+		 * In canonical mode check for a "break character"
+		 * marking the end of a "line of input".
+		 */
+		if (ISSET(lflag, ICANON) && TTBREAKC(c))
+			break;
+		first = 0;
+	}
+	/*
+	 * Look to unblock output now that (presumably)
+	 * the input queue has gone down.
+	 */
+	s = spltty();
+	if (ISSET(tp->t_state, TS_TBLOCK) && tp->t_rawq.c_cc < TTYHOG/5) {
+		if (cc[VSTART] != _POSIX_VDISABLE &&
+		    putc(cc[VSTART], &tp->t_outq) == 0) {
+			CLR(tp->t_state, TS_TBLOCK);
+			ttstart(tp);
+		}
+	}
+	splx(s);
+	return (error);
+}
+
+/*
+ * Check the output queue on tp for space for a kernel message (from uprintf
+ * or tprintf).  Allow some space over the normal hiwater mark so we don't
+ * lose messages due to normal flow control, but don't let the tty run amok.
+ * Sleeps here are not interruptible, but we return prematurely if new signals
+ * arrive.
+ */
+int
+ttycheckoutq(tp, wait)
+	register struct tty *tp;
+	int wait;
+{
+	int hiwat, s, oldsig;
+
+	hiwat = tp->t_hiwat;
+	s = spltty();
+	oldsig = wait ? curproc->p_siglist : 0;
+	if (tp->t_outq.c_cc > hiwat + 200)
+		while (tp->t_outq.c_cc > hiwat) {
+			ttstart(tp);
+			if (wait == 0 || curproc->p_siglist != oldsig) {
+				splx(s);
+				return (0);
+			}
+			timeout((void (*)__P((void *)))wakeup,
+			    (void *)&tp->t_outq, hz);
+			SET(tp->t_state, TS_ASLEEP);
+			sleep((caddr_t)&tp->t_outq, PZERO - 1);
+		}
+	splx(s);
+	return (1);
+}
+
+/*
+ * Process a write call on a tty device.
+ */
+int
+ttwrite(tp, uio, flag)
+	register struct tty *tp;
+	register struct uio *uio;
+	int flag;
+{
+	register char *cp;
+	register int cc, ce;
+	register struct proc *p;
+	int i, hiwat, cnt, error, s;
+	char obuf[OBUFSIZ];
+
+	hiwat = tp->t_hiwat;
+	cnt = uio->uio_resid;
+	error = 0;
+	cc = 0;
+loop:
+	s = spltty();
+	if (!ISSET(tp->t_state, TS_CARR_ON) &&
+	    !ISSET(tp->t_cflag, CLOCAL)) {
+		if (ISSET(tp->t_state, TS_ISOPEN)) {
+			splx(s);
+			return (EIO);
+		} else if (flag & IO_NDELAY) {
+			splx(s);
+			error = EWOULDBLOCK;
+			goto out;
+		} else {
+			/* Sleep awaiting carrier. */
+			error = ttysleep(tp,
+			    &tp->t_rawq, TTIPRI | PCATCH,ttopen, 0);
+			splx(s);
+			if (error)
+				goto out;
+			goto loop;
+		}
+	}
+	splx(s);
+	/*
+	 * Hang the process if it's in the background.
+	 */
+	p = curproc;
+	if (isbackground(p, tp) &&
+	    ISSET(tp->t_lflag, TOSTOP) && (p->p_flag & P_PPWAIT) == 0 &&
+	    (p->p_sigignore & sigmask(SIGTTOU)) == 0 &&
+	    (p->p_sigmask & sigmask(SIGTTOU)) == 0 &&
+	     p->p_pgrp->pg_jobc) {
+		pgsignal(p->p_pgrp, SIGTTOU, 1);
+		if (error = ttysleep(tp, &lbolt, TTIPRI | PCATCH, ttybg, 0))
+			goto out;
+		goto loop;
+	}
+	/*
+	 * Process the user's data in at most OBUFSIZ chunks.  Perform any
+	 * output translation.  Keep track of high water mark, sleep on
+	 * overflow awaiting device aid in acquiring new space.
+	 */
+	while (uio->uio_resid > 0 || cc > 0) {
+		if (ISSET(tp->t_lflag, FLUSHO)) {
+			uio->uio_resid = 0;
+			return (0);
+		}
+		if (tp->t_outq.c_cc > hiwat)
+			goto ovhiwat;
+		/*
+		 * Grab a hunk of data from the user, unless we have some
+		 * leftover from last time.
+		 */
+		if (cc == 0) {
+			cc = min(uio->uio_resid, OBUFSIZ);
+			cp = obuf;
+			error = uiomove(cp, cc, uio);
+			if (error) {
+				cc = 0;
+				break;
+			}
+		}
+		/*
+		 * If nothing fancy need be done, grab those characters we
+		 * can handle without any of ttyoutput's processing and
+		 * just transfer them to the output q.  For those chars
+		 * which require special processing (as indicated by the
+		 * bits in char_type), call ttyoutput.  After processing
+		 * a hunk of data, look for FLUSHO so ^O's will take effect
+		 * immediately.
+		 */
+		while (cc > 0) {
+			if (!ISSET(tp->t_oflag, OPOST))
+				ce = cc;
+			else {
+				ce = cc - scanc((u_int)cc, (u_char *)cp,
+				   (u_char *)char_type, CCLASSMASK);
+				/*
+				 * If ce is zero, then we're processing
+				 * a special character through ttyoutput.
+				 */
+				if (ce == 0) {
+					tp->t_rocount = 0;
+					if (ttyoutput(*cp, tp) >= 0) {
+						/* No Clists, wait a bit. */
+						ttstart(tp);
+						if (error = ttysleep(tp, &lbolt,
+						    TTOPRI | PCATCH, ttybuf, 0))
+							break;
+						goto loop;
+					}
+					cp++;
+					cc--;
+					if (ISSET(tp->t_lflag, FLUSHO) ||
+					    tp->t_outq.c_cc > hiwat)
+						goto ovhiwat;
+					continue;
+				}
+			}
+			/*
+			 * A bunch of normal characters have been found.
+			 * Transfer them en masse to the output queue and
+			 * continue processing at the top of the loop.
+			 * If there are any further characters in this
+			 * <= OBUFSIZ chunk, the first should be a character
+			 * requiring special handling by ttyoutput.
+			 */
+			tp->t_rocount = 0;
+			i = b_to_q(cp, ce, &tp->t_outq);
+			ce -= i;
+			tp->t_column += ce;
+			cp += ce, cc -= ce, tk_nout += ce;
+			tp->t_outcc += ce;
+			if (i > 0) {
+				/* No Clists, wait a bit. */
+				ttstart(tp);
+				if (error = ttysleep(tp,
+				    &lbolt, TTOPRI | PCATCH, ttybuf, 0))
+					break;
+				goto loop;
+			}
+			if (ISSET(tp->t_lflag, FLUSHO) ||
+			    tp->t_outq.c_cc > hiwat)
+				break;
+		}
+		ttstart(tp);
+	}
+out:
+	/*
+	 * If cc is nonzero, we leave the uio structure inconsistent, as the
+	 * offset and iov pointers have moved forward, but it doesn't matter
+	 * (the call will either return short or restart with a new uio).
+	 */
+	uio->uio_resid += cc;
+	return (error);
+
+ovhiwat:
+	ttstart(tp);
+	s = spltty();
+	/*
+	 * This can only occur if FLUSHO is set in t_lflag,
+	 * or if ttstart/oproc is synchronous (or very fast).
+	 */
+	if (tp->t_outq.c_cc <= hiwat) {
+		splx(s);
+		goto loop;
+	}
+	if (flag & IO_NDELAY) {
+		splx(s);
+		uio->uio_resid += cc;
+		return (uio->uio_resid == cnt ? EWOULDBLOCK : 0);
+	}
+	SET(tp->t_state, TS_ASLEEP);
+	error = ttysleep(tp, &tp->t_outq, TTOPRI | PCATCH, ttyout, 0);
+	splx(s);
+	if (error)
+		goto out;
+	goto loop;
+}
+
+/*
+ * Rubout one character from the rawq of tp
+ * as cleanly as possible.
+ */
+void
+ttyrub(c, tp)
+	register int c;
+	register struct tty *tp;
+{
+	register char *cp;
+	register int savecol;
+	int tabc, s;
+
+	if (!ISSET(tp->t_lflag, ECHO) || ISSET(tp->t_lflag, EXTPROC))
+		return;
+	CLR(tp->t_lflag, FLUSHO);
+	if (ISSET(tp->t_lflag, ECHOE)) {
+		if (tp->t_rocount == 0) {
+			/*
+			 * Screwed by ttwrite; retype
+			 */
+			ttyretype(tp);
+			return;
+		}
+		if (c == ('\t' | TTY_QUOTE) || c == ('\n' | TTY_QUOTE))
+			ttyrubo(tp, 2);
+		else {
+			CLR(c, ~TTY_CHARMASK);
+			switch (CCLASS(c)) {
+			case ORDINARY:
+				ttyrubo(tp, 1);
+				break;
+			case BACKSPACE:
+			case CONTROL:
+			case NEWLINE:
+			case RETURN:
+			case VTAB:
+				if (ISSET(tp->t_lflag, ECHOCTL))
+					ttyrubo(tp, 2);
+				break;
+			case TAB:
+				if (tp->t_rocount < tp->t_rawq.c_cc) {
+					ttyretype(tp);
+					return;
+				}
+				s = spltty();
+				savecol = tp->t_column;
+				SET(tp->t_state, TS_CNTTB);
+				SET(tp->t_lflag, FLUSHO);
+				tp->t_column = tp->t_rocol;
+				cp = tp->t_rawq.c_cf;
+				if (cp)
+					tabc = *cp;	/* XXX FIX NEXTC */
+				for (; cp; cp = nextc(&tp->t_rawq, cp, &tabc))
+					ttyecho(tabc, tp);
+				CLR(tp->t_lflag, FLUSHO);
+				CLR(tp->t_state, TS_CNTTB);
+				splx(s);
+
+				/* savecol will now be length of the tab. */
+				savecol -= tp->t_column;
+				tp->t_column += savecol;
+				if (savecol > 8)
+					savecol = 8;	/* overflow screw */
+				while (--savecol >= 0)
+					(void)ttyoutput('\b', tp);
+				break;
+			default:			/* XXX */
+#define	PANICSTR	"ttyrub: would panic c = %d, val = %d\n"
+				(void)printf(PANICSTR, c, CCLASS(c));
+#ifdef notdef
+				panic(PANICSTR, c, CCLASS(c));
+#endif
+			}
+		}
+	} else if (ISSET(tp->t_lflag, ECHOPRT)) {
+		if (!ISSET(tp->t_state, TS_ERASE)) {
+			SET(tp->t_state, TS_ERASE);
+			(void)ttyoutput('\\', tp);
+		}
+		ttyecho(c, tp);
+	} else
+		ttyecho(tp->t_cc[VERASE], tp);
+	--tp->t_rocount;
+}
+
+/*
+ * Back over cnt characters, erasing them.
+ */
+static void
+ttyrubo(tp, cnt)
+	register struct tty *tp;
+	int cnt;
+{
+
+	while (cnt-- > 0) {
+		(void)ttyoutput('\b', tp);
+		(void)ttyoutput(' ', tp);
+		(void)ttyoutput('\b', tp);
+	}
+}
+
+/*
+ * ttyretype --
+ *	Reprint the rawq line.  Note, it is assumed that c_cc has already
+ *	been checked.
+ */
+void
+ttyretype(tp)
+	register struct tty *tp;
+{
+	register char *cp;
+	int s, c;
+
+	/* Echo the reprint character. */
+	if (tp->t_cc[VREPRINT] != _POSIX_VDISABLE)
+		ttyecho(tp->t_cc[VREPRINT], tp);
+
+	(void)ttyoutput('\n', tp);
+
+	/*
+	 * XXX
+	 * FIX: NEXTC IS BROKEN - DOESN'T CHECK QUOTE
+	 * BIT OF FIRST CHAR.
+	 */
+	s = spltty();
+	for (cp = tp->t_canq.c_cf, c = (cp != NULL ? *cp : 0);
+	    cp != NULL; cp = nextc(&tp->t_canq, cp, &c))
+		ttyecho(c, tp);
+	for (cp = tp->t_rawq.c_cf, c = (cp != NULL ? *cp : 0);
+	    cp != NULL; cp = nextc(&tp->t_rawq, cp, &c))
+		ttyecho(c, tp);
+	CLR(tp->t_state, TS_ERASE);
+	splx(s);
+
+	tp->t_rocount = tp->t_rawq.c_cc;
+	tp->t_rocol = 0;
+}
+
+/*
+ * Echo a typed character to the terminal.
+ */
+static void
+ttyecho(c, tp)
+	register int c;
+	register struct tty *tp;
+{
+
+	if (!ISSET(tp->t_state, TS_CNTTB))
+		CLR(tp->t_lflag, FLUSHO);
+	if ((!ISSET(tp->t_lflag, ECHO) &&
+	    (!ISSET(tp->t_lflag, ECHONL) || c == '\n')) ||
+	    ISSET(tp->t_lflag, EXTPROC))
+		return;
+	if (ISSET(tp->t_lflag, ECHOCTL) &&
+	    (ISSET(c, TTY_CHARMASK) <= 037 && c != '\t' && c != '\n' ||
+	    ISSET(c, TTY_CHARMASK) == 0177)) {
+		(void)ttyoutput('^', tp);
+		CLR(c, ~TTY_CHARMASK);
+		if (c == 0177)
+			c = '?';
+		else
+			c += 'A' - 1;
+	}
+	(void)ttyoutput(c, tp);
+}
+
+/*
+ * Wake up any readers on a tty.
+ */
+void
+ttwakeup(tp)
+	register struct tty *tp;
+{
+
+	selwakeup(&tp->t_rsel);
+	if (ISSET(tp->t_state, TS_ASYNC))
+		pgsignal(tp->t_pgrp, SIGIO, 1);
+	wakeup((caddr_t)&tp->t_rawq);
+}
+
+/*
+ * Look up a code for a specified speed in a conversion table;
+ * used by drivers to map software speed values to hardware parameters.
+ */
+int
+ttspeedtab(speed, table)
+	int speed;
+	register struct speedtab *table;
+{
+
+	for ( ; table->sp_speed != -1; table++)
+		if (table->sp_speed == speed)
+			return (table->sp_code);
+	return (-1);
+}
+
+/*
+ * Set tty hi and low water marks.
+ *
+ * Try to arrange the dynamics so there's about one second
+ * from hi to low water.
+ *
+ */
+void
+ttsetwater(tp)
+	struct tty *tp;
+{
+	register int cps, x;
+
+#define CLAMP(x, h, l)	((x) > h ? h : ((x) < l) ? l : (x))
+
+	cps = tp->t_ospeed / 10;
+	tp->t_lowat = x = CLAMP(cps / 2, TTMAXLOWAT, TTMINLOWAT);
+	x += cps;
+	x = CLAMP(x, TTMAXHIWAT, TTMINHIWAT);
+	tp->t_hiwat = roundup(x, CBSIZE);
+#undef	CLAMP
+}
+
+/*
+ * Report on state of foreground process group.
+ */
+void
+ttyinfo(tp)
+	register struct tty *tp;
+{
+	register struct proc *p, *pick;
+	struct timeval utime, stime;
+	int tmp;
+
+	if (ttycheckoutq(tp,0) == 0)
+		return;
+
+	/* Print load average. */
+	tmp = (averunnable.ldavg[0] * 100 + FSCALE / 2) >> FSHIFT;
+	ttyprintf(tp, "load: %d.%02d ", tmp / 100, tmp % 100);
+
+	if (tp->t_session == NULL)
+		ttyprintf(tp, "not a controlling terminal\n");
+	else if (tp->t_pgrp == NULL)
+		ttyprintf(tp, "no foreground process group\n");
+	else if ((p = tp->t_pgrp->pg_mem) == NULL)
+		ttyprintf(tp, "empty foreground process group\n");
+	else {
+		/* Pick interesting process. */
+		for (pick = NULL; p != NULL; p = p->p_pgrpnxt)
+			if (proc_compare(pick, p))
+				pick = p;
+
+		ttyprintf(tp, " cmd: %s %d [%s] ", pick->p_comm, pick->p_pid,
+		    pick->p_stat == SRUN ? "running" :
+		    pick->p_wmesg ? pick->p_wmesg : "iowait");
+
+		calcru(pick, &utime, &stime, NULL);
+
+		/* Print user time. */
+		ttyprintf(tp, "%d.%02du ",
+		    utime.tv_sec, (utime.tv_usec + 5000) / 10000);
+
+		/* Print system time. */
+		ttyprintf(tp, "%d.%02ds ",
+		    stime.tv_sec, (stime.tv_usec + 5000) / 10000);
+
+#define	pgtok(a)	(((a) * NBPG) / 1024)
+		/* Print percentage cpu, resident set size. */
+		tmp = pick->p_pctcpu * 10000 + FSCALE / 2 >> FSHIFT;
+		ttyprintf(tp, "%d%% %dk\n",
+		    tmp / 100,
+		    pick->p_stat == SIDL || pick->p_stat == SZOMB ? 0 :
+#ifdef pmap_resident_count
+			pgtok(pmap_resident_count(&pick->p_vmspace->vm_pmap))
+#else
+			pgtok(pick->p_vmspace->vm_rssize)
+#endif
+			);
+	}
+	tp->t_rocount = 0;	/* so pending input will be retyped if BS */
+}
+
+/*
+ * Returns 1 if p2 is "better" than p1
+ *
+ * The algorithm for picking the "interesting" process is thus:
+ *
+ *	1) Only foreground processes are eligible - implied.
+ *	2) Runnable processes are favored over anything else.  The runner
+ *	   with the highest cpu utilization is picked (p_estcpu).  Ties are
+ *	   broken by picking the highest pid.
+ *	3) The sleeper with the shortest sleep time is next.  With ties,
+ *	   we pick out just "short-term" sleepers (P_SINTR == 0).
+ *	4) Further ties are broken by picking the highest pid.
+ */
+#define ISRUN(p)	(((p)->p_stat == SRUN) || ((p)->p_stat == SIDL))
+#define TESTAB(a, b)    ((a)<<1 | (b))
+#define ONLYA   2
+#define ONLYB   1
+#define BOTH    3
+
+static int
+proc_compare(p1, p2)
+	register struct proc *p1, *p2;
+{
+
+	if (p1 == NULL)
+		return (1);
+	/*
+	 * see if at least one of them is runnable
+	 */
+	switch (TESTAB(ISRUN(p1), ISRUN(p2))) {
+	case ONLYA:
+		return (0);
+	case ONLYB:
+		return (1);
+	case BOTH:
+		/*
+		 * tie - favor one with highest recent cpu utilization
+		 */
+		if (p2->p_estcpu > p1->p_estcpu)
+			return (1);
+		if (p1->p_estcpu > p2->p_estcpu)
+			return (0);
+		return (p2->p_pid > p1->p_pid);	/* tie - return highest pid */
+	}
+	/*
+ 	 * weed out zombies
+	 */
+	switch (TESTAB(p1->p_stat == SZOMB, p2->p_stat == SZOMB)) {
+	case ONLYA:
+		return (1);
+	case ONLYB:
+		return (0);
+	case BOTH:
+		return (p2->p_pid > p1->p_pid); /* tie - return highest pid */
+	}
+	/*
+	 * pick the one with the smallest sleep time
+	 */
+	if (p2->p_slptime > p1->p_slptime)
+		return (0);
+	if (p1->p_slptime > p2->p_slptime)
+		return (1);
+	/*
+	 * favor one sleeping in a non-interruptible sleep
+	 */
+	if (p1->p_flag & P_SINTR && (p2->p_flag & P_SINTR) == 0)
+		return (1);
+	if (p2->p_flag & P_SINTR && (p1->p_flag & P_SINTR) == 0)
+		return (0);
+	return (p2->p_pid > p1->p_pid);		/* tie - return highest pid */
+}
+
+/*
+ * Output char to tty; console putchar style.
+ */
+int
+tputchar(c, tp)
+	int c;
+	struct tty *tp;
+{
+	register int s;
+
+	s = spltty();
+	if (ISSET(tp->t_state,
+	    TS_CARR_ON | TS_ISOPEN) != (TS_CARR_ON | TS_ISOPEN)) {
+		splx(s);
+		return (-1);
+	}
+	if (c == '\n')
+		(void)ttyoutput('\r', tp);
+	(void)ttyoutput(c, tp);
+	ttstart(tp);
+	splx(s);
+	return (0);
+}
+
+/*
+ * Sleep on chan, returning ERESTART if tty changed while we napped and
+ * returning any errors (e.g. EINTR/ETIMEDOUT) reported by tsleep.  If
+ * the tty is revoked, restarting a pending call will redo validation done
+ * at the start of the call.
+ */
+int
+ttysleep(tp, chan, pri, wmesg, timo)
+	struct tty *tp;
+	void *chan;
+	int pri, timo;
+	char *wmesg;
+{
+	int error;
+	short gen;
+
+	gen = tp->t_gen;
+	if (error = tsleep(chan, pri, wmesg, timo))
+		return (error);
+	return (tp->t_gen == gen ? 0 : ERESTART);
+}