tty.c

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/*
 * Copyright (c) 1997-1998 University of Utah and the Flux Group.
 * All rights reserved.
 * 
 * This file is part of the Flux OSKit.  The OSKit is free software, also known
 * as "open source;" you can redistribute it and/or modify it under the terms
 * of the GNU General Public License (GPL), version 2, as published by the Free
 * Software Foundation (FSF).  To explore alternate licensing terms, contact
 * the University of Utah at [e-mail] or [phone].
 * 
 * The OSKit is distributed in the hope that it will be useful, but WITHOUT ANY
 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE.  See the GPL for more details.  You should have
 * received a copy of the GPL along with the OSKit; see the file COPYING.  If
 * not, write to the FSF, 59 Temple Place #330, Boston, MA 02111-1307, USA.
 */
/*-
 * 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
 * $\Id: tty.c,v 1.46.2.3 1996/01/03 17:59:21 davidg Exp $
 */

/*-
 * TODO:
 *	o Fix races for sending the start char in ttyflush().
 *	o Handle inter-byte timeout for "MIN > 0, TIME > 0" in ttyselect().
 *	  With luck, there will be MIN chars before select() returns().
 *	o Handle CLOCAL consistently for ptys.  Perhaps disallow setting it.
 *	o Don't allow input in TS_ZOMBIE case.  It would be visible through
 *	  FIONREAD.
 *	o Do the new sio locking stuff here and use it to avoid special
 *	  case for EXTPROC?
 *	o Lock PENDIN too?
 *	o Move EXTPROC and/or PENDIN to t_state?
 *	o Wrap most of ttioctl in spltty/splx.
 *	o Implement TIOCNOTTY or remove it from <sys/ioctl.h>.
 *	o Send STOP if IXOFF is toggled off while TS_TBLOCK is set.
 *	o Don't allow certain termios flags to affect disciplines other
 *	  than TTYDISC.  Cancel their effects before switch disciplines
 *	  and ignore them if they are set while we are in another
 *	  discipline.
 *	o Handle c_ispeed = 0 to c_ispeed = c_ospeed conversion here instead
 *	  of in drivers and fix drivers that write to tp->t_termios.
 *	o Check for TS_CARR_ON being set while everything is closed and not
 *	  waiting for carrier.  TS_CARR_ON isn't cleared if nothing is open,
 *	  so it would live until the next open even if carrier drops.
 *	o Restore TS_WOPEN since it is useful in pstat.  It must be cleared
 *	  only when _all_ openers leave open().
 */

#include "snp.h"

#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 <sys/signalvar.h>
#include <sys/resourcevar.h>
#include <sys/malloc.h>
#if NSNP > 0
#include <sys/snoop.h>
#endif

#include <vm/vm.h>

static int	proc_compare __P((struct proc *p1, struct proc *p2));
static int	ttnread __P((struct tty *tp));
static void	ttyecho __P((int c, struct tty *tp));
static int	ttyoutput __P((int c, register struct tty *tp));
static void	ttypend __P((struct tty *tp));
static void	ttyretype __P((struct tty *tp));
static void	ttyrub __P((int c, struct tty *tp));
static void	ttyrubo __P((struct tty *tp, int cnt));
static void	ttyunblock __P((struct tty *tp));

/*
 * 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))

/*
 * Input control starts when we would not be able to fit the maximum
 * contents of the ping-pong buffers and finishes when we would be able
 * to fit that much plus 1/8 more.
 */
#define	I_HIGH_WATER	(TTYHOG - 2 * 256)	/* XXX */
#define	I_LOW_WATER	((TTYHOG - 2 * 256) * 7 / 8)	/* XXX */

#undef MAX_INPUT		/* XXX wrong in <sys/syslimits.h> */
#define	MAX_INPUT	TTYHOG

/*
 * 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);
		if (ISSET(tp->t_cflag, CLOCAL))
			SET(tp->t_state, TS_CONNECTED);
		bzero(&tp->t_winsize, sizeof(tp->t_winsize));
	}

	/*
	 * Initialize or restore a cblock allocation policy suitable for
	 * the standard line discipline.
	 */
	clist_alloc_cblocks(&tp->t_canq, TTYHOG, 512);
	clist_alloc_cblocks(&tp->t_outq, TTMAXHIWAT + OBUFSIZ + 100,
			    TTMAXHIWAT + OBUFSIZ + 100);
	clist_alloc_cblocks(&tp->t_rawq, TTYHOG, TTYHOG);

	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.
 * XXX our caller should have done `spltty(); l_close(); ttyclose();'
 * and l_close() should have flushed, but we repeat the spltty() and
 * the flush in case there are buggy callers.
 */
int
ttyclose(tp)
	register struct tty *tp;
{
	int s;

	s = spltty();
	if (constty == tp)
		constty = NULL;

	ttyflush(tp, FREAD | FWRITE);
	clist_free_cblocks(&tp->t_canq);
	clist_free_cblocks(&tp->t_outq);
	clist_free_cblocks(&tp->t_rawq);

#if NSNP > 0
	if (ISSET(tp->t_state, TS_SNOOP) && tp->t_sc != NULL)
		snpdown((struct snoop *)tp->t_sc);
#endif

	tp->t_gen++;
	tp->t_line = TTYDISC;
	tp->t_pgrp = NULL;
	tp->t_session = NULL;
	tp->t_state = 0;
	splx(s);
	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 tcflag_t iflag, lflag;
	register cc_t *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;

	/*
	 * Block further input iff:
	 * current input > threshold AND input is available to user program
	 * AND input flow control is enabled and not yet invoked.
	 * The 3 is slop for PARMRK.
	 */
	iflag = tp->t_iflag;
	if (tp->t_rawq.c_cc + tp->t_canq.c_cc > I_HIGH_WATER - 3 &&
	    (!ISSET(lflag, ICANON) || tp->t_canq.c_cc != 0) &&
	    (ISSET(tp->t_cflag, CRTS_IFLOW) || ISSET(iflag, IXOFF)) &&
	    !ISSET(tp->t_state, TS_TBLOCK))
		ttyblock(tp);

	/* Handle exceptional conditions (break, parity, framing). */
	cc = tp->t_cc;
	err = (ISSET(c, TTY_ERRORMASK));
	if (err) {
		CLR(c, TTY_ERRORMASK);
		if (ISSET(err, TTY_BI)) { /* Break. */
			if (ISSET(iflag, IGNBRK))
				return (0);
			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))
				return (0);
			else if (ISSET(iflag, PARMRK)) {
parmrk:
				if (tp->t_rawq.c_cc + tp->t_canq.c_cc >
				    MAX_INPUT - 3)
					goto input_overflow;
				(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;
		}
	}

	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))
				return (0);
			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 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' &&
			    (!ISSET(lflag, ALTWERASE) || 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 >= MAX_INPUT) {
input_overflow:
		if (ISSET(iflag, IMAXBEL)) {
			if (tp->t_outq.c_cc < tp->t_hiwat)
				(void)ttyoutput(CTRL('g'), tp);
		}
		goto endcase;
	}

	if (   c == 0377 && ISSET(iflag, PARMRK) && !ISSET(iflag, ISTRIP)
	     && ISSET(iflag, IGNBRK|IGNPAR) != (IGNBRK|IGNPAR))
		(void)putc(0377 | TTY_QUOTE, &tp->t_rawq);

	/*
	 * 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 = imin(2, tp->t_column - i);
			while (i > 0) {
				(void)ttyoutput('\b', tp);