xnu-792.13.8.tar.gz

[apple/xnu.git] / osfmk / ddb / db_input.c

/*
 * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_OSREFERENCE_HEADER_START@
 * 
 * This file contains Original Code and/or Modifications of Original Code 
 * as defined in and that are subject to the Apple Public Source License 
 * Version 2.0 (the 'License'). You may not use this file except in 
 * compliance with the License.  The rights granted to you under the 
 * License may not be used to create, or enable the creation or 
 * redistribution of, unlawful or unlicensed copies of an Apple operating 
 * system, or to circumvent, violate, or enable the circumvention or 
 * violation of, any terms of an Apple operating system software license 
 * agreement.
 *
 * Please obtain a copy of the License at 
 * http://www.opensource.apple.com/apsl/ and read it before using this 
 * file.
 *
 * The Original Code and all software distributed under the License are 
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER 
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, 
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, 
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. 
 * Please see the License for the specific language governing rights and 
 * limitations under the License.
 *
 * @APPLE_LICENSE_OSREFERENCE_HEADER_END@
 */
/*
 * @OSF_COPYRIGHT@
 */
/*
 * HISTORY
 * 
 * Revision 1.1.1.1  1998/09/22 21:05:48  wsanchez
 * Import of Mac OS X kernel (~semeria)
 *
 * Revision 1.1.1.1  1998/03/07 02:26:09  wsanchez
 * Import of OSF Mach kernel (~mburg)
 *
 * Revision 1.3.10.2  1994/09/23  01:19:37  ezf
 * 	change marker to not FREE
 * 	[1994/09/22  21:10:05  ezf]
 *
 * Revision 1.3.10.1  1994/06/11  21:11:48  bolinger
 * 	Merge up to NMK17.2.
 * 	[1994/06/11  20:01:41  bolinger]
 * 
 * Revision 1.3.8.2  1994/02/11  14:21:41  paire
 * 	Added string.h header file for strlen declaration.
 * 	[94/02/09            paire]
 * 
 * Revision 1.3.8.1  1994/02/08  10:57:55  bernadat
 * 	Added db_auto_completion variable.
 * 	[93/08/17            paire]
 * 
 * 	Added support of symbol completion by typing '\t'.
 * 	[93/08/14            paire]
 * 	[94/02/07            bernadat]
 * 
 * Revision 1.3.2.4  1993/08/11  20:37:51  elliston
 * 	Add ANSI Prototypes.  CR #9523.
 * 	[1993/08/11  03:33:21  elliston]
 * 
 * Revision 1.3.2.3  1993/07/27  18:27:30  elliston
 * 	Add ANSI prototypes.  CR #9523.
 * 	[1993/07/27  18:12:01  elliston]
 * 
 * Revision 1.3.2.2  1993/06/09  02:20:13  gm
 * 	CR9176 - ANSI C violations: trailing tokens on CPP
 * 	directives, extra semicolons after decl_ ..., asm keywords
 * 	[1993/06/07  18:57:14  jeffc]
 * 
 * 	Added to OSF/1 R1.3 from NMK15.0.
 * 	[1993/06/02  20:56:26  jeffc]
 * 
 * Revision 1.3  1993/04/19  16:02:17  devrcs
 * 	Replaced ^R (redraw) with ^L [barbou@gr.osf.org]
 * 
 * 	Added ^R and ^S commands for history search commands
 * 	^U does not erase end of the line anymore. (only erases
 * 	from the beginning of the line to current position).
 * 	[barbou@gr.osf.org]
 * 
 * 	^C now erases the entire line. [barbou@gr.osf.org]
 * 	[92/12/03            bernadat]
 * 
 * 	Fixed history management: Do not store repeated typed
 * 	command. Null terminate current command in case it is a
 * 	substring of the last command.
 * 	[92/10/02            bernadat]
 * 
 * Revision 1.2  1992/11/25  01:04:24  robert
 * 	integrate changes for norma_14 below
 * 
 * 	Philippe Bernadat (bernadat) at gr.osf.org 02-Oct-92
 * 	Fixed history management: Do not store repeated typed
 * 	command. Null terminate current command in case it is a
 * 	substring of the last command.
 * 	[1992/11/20  00:56:07  robert]
 * 
 * 	integrate changes below for norma_14
 * 	[1992/11/13  19:21:34  robert]
 * 
 * Revision 1.1  1992/09/30  02:01:08  robert
 * 	Initial revision
 * 
 * $EndLog$
 */
/* CMU_HIST */
/*
 * Revision 2.7.3.2  92/09/15  17:14:26  jeffreyh
 * 	Fixed history code. (Only one char. out of 2 was checked to
 * 	compare to last command)
 * 	[barbou@gr.osf.org]
 * 
 * Revision 2.7.3.1  92/03/03  16:13:30  jeffreyh
 * 	Pick up changes from TRUNK
 * 	[92/02/26  10:59:36  jeffreyh]
 * 
 * Revision 2.8  92/02/19  15:07:44  elf
 * 	Added delete_line (Ctrl-U).
 * 	[92/02/17            kivinen]
 * 
 * 	Added command line history. Ctrl-P = previous, Ctrl-N = next. If
 * 	DB_HISTORY_SIZE is 0 then command history is disabled.
 * 	[92/02/17            kivinen]
 * 
 * Revision 2.7  91/10/09  16:00:03  af
 * 	 Revision 2.6.2.1  91/10/05  13:06:12  jeffreyh
 * 	 	Fixed incorrect db_lbuf_end setting.
 * 	 	[91/08/29            tak]
 * 
 * Revision 2.6.2.1  91/10/05  13:06:12  jeffreyh
 * 	Fixed incorrect db_lbuf_end setting.
 * 	[91/08/29            tak]
 * 
 * Revision 2.6  91/07/09  23:15:49  danner
 * 	Add include of machine/db_machdep.h to allow machine-specific
 * 	 overrides via defines.
 * 	[91/07/08            danner]
 *
 * Revision 2.5  91/05/14  15:34:03  mrt
 * 	Correcting copyright
 * 
 * Revision 2.4  91/02/14  14:41:53  mrt
 * 	Add input line editing.
 * 	[90/11/11            dbg]
 * 
 * Revision 2.3  91/02/05  17:06:32  mrt
 * 	Changed to new Mach copyright
 * 	[91/01/31  16:18:13  mrt]
 * 
 * Revision 2.2  90/08/27  21:51:03  dbg
 * 	Reduce lint.
 * 	[90/08/07            dbg]
 * 	Created.
 * 	[90/07/25            dbg]
 * 
 */
/* CMU_ENDHIST */
/* 
 * Mach Operating System
 * Copyright (c) 1991,1990 Carnegie Mellon University
 * All Rights Reserved.
 * 
 * Permission to use, copy, modify and distribute this software and its
 * documentation is hereby granted, provided that both the copyright
 * notice and this permission notice appear in all copies of the
 * software, derivative works or modified versions, and any portions
 * thereof, and that both notices appear in supporting documentation.
 * 
 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
 * 
 * Carnegie Mellon requests users of this software to return to
 * 
 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
 *  School of Computer Science
 *  Carnegie Mellon University
 *  Pittsburgh PA 15213-3890
 * 
 * any improvements or extensions that they make and grant Carnegie Mellon
 * the rights to redistribute these changes.
 */
/*
 */
/*
 *	Author: David B. Golub, Carnegie Mellon University
 *	Date:	7/90
 */

#include <string.h>
#include <mach/boolean.h>
#include <machine/db_machdep.h>
#include <kern/misc_protos.h>
#include <ddb/db_output.h>
#include <ddb/db_lex.h>
#include <ddb/db_command.h>
#include <ddb/db_input.h>
#include <ddb/db_sym.h>

#ifndef DB_HISTORY_SIZE
#define DB_HISTORY_SIZE 4000
#endif /* DB_HISTORY_SIZE */

/*
 * Character input and editing.
 */

/*
 * We don't track output position while editing input,
 * since input always ends with a new-line.  We just
 * reset the line position at the end.
 */
char *	db_lbuf_start;	/* start of input line buffer */
char *	db_lbuf_end;	/* end of input line buffer */
char *	db_lc;		/* current character */
char *	db_le;		/* one past last character */
int	db_completion;	/* number of incomplete symbols matched */
int	db_auto_completion = 10; /* number of line to display without asking */
#if DB_HISTORY_SIZE != 0
char    db_history[DB_HISTORY_SIZE];	/* start of history buffer */
int     db_history_size = DB_HISTORY_SIZE;/* size of history buffer */
char *  db_history_curr = db_history;	/* start of current line */
char *  db_history_last = db_history;	/* start of last line */
char *  db_history_prev = (char *) 0;	/* start of previous line */
int	db_hist_unmodified = 0;		/* unmodified line from history */
int	db_hist_search = 0;		/* are we in hist search mode ? */
char 	db_hist_search_string[DB_LEX_LINE_SIZE];/* the string to look for */
int	db_hist_ignore_dups = 0;	/* don't duplicate commands in hist */
#endif
	
#define	CTRL(c)		((c) & 0x1f)
#define	isspace(c)	((c) == ' ' || (c) == '\t')
#define	BLANK		' '
#define	BACKUP		'\b'



/* Prototypes for functions local to this file.  XXX -- should be static!
 */
void db_putstring(
	char	*s,
	int	count);

void db_putnchars(
	int	c,
	int	count);

void db_delete(
	int	n,
	int	bwd);

void db_delete_line(void);

boolean_t db_hist_substring(
	char	*string,
	char	*substring);

boolean_t db_inputchar(int c);

extern jmp_buf_t	*db_recover;

void
db_putstring(
	char	*s,
	int	count)
{
	while (--count >= 0)
	    cnputc(*s++);
}

void
db_putnchars(
	int	c,
	int	count)
{
	while (--count >= 0)
	    cnputc(c);
}

/*
 * Delete N characters, forward or backward
 */
#define	DEL_FWD		0
#define	DEL_BWD		1
void
db_delete(
	int	n,
	int	bwd)
{
	register char *p;

	if (bwd) {
	    db_lc -= n;
	    db_putnchars(BACKUP, n);
	}
	for (p = db_lc; p < db_le-n; p++) {
	    *p = *(p+n);
	    cnputc(*p);
	}
	db_putnchars(BLANK, n);
	db_putnchars(BACKUP, db_le - db_lc);
	db_le -= n;
}

void
db_delete_line(void)
{
	db_delete(db_le - db_lc, DEL_FWD);
	db_delete(db_lc - db_lbuf_start, DEL_BWD);
	db_le = db_lc = db_lbuf_start;
}

#if DB_HISTORY_SIZE != 0
#define INC_DB_CURR() \
    do { \
	     db_history_curr++; \
	     if (db_history_curr > \
		 db_history + db_history_size - 1) \
		     db_history_curr = db_history; \
       } while (0)
#define DEC_DB_CURR() \
    do { \
	     db_history_curr--; \
	     if (db_history_curr < db_history) \
		 db_history_curr = db_history + \
		 db_history_size - 1; \
       } while (0)
#endif
		
/* returs TRUE if "substring" is a substring of "string" */
boolean_t
db_hist_substring(
	char	*string,
	char	*substring)
{
	register char *cp1, *cp2;

	cp1 = string;
	while (*cp1)
		cp1++;
	cp2 = substring;
	while (*cp2)
		cp2++;

	while (cp2 > substring) {
		cp1--; cp2--;
	}
	
	while (cp1 >= string) {
		register char *cp3;

		cp2 = substring;
		cp3 = cp1;
		while (*cp2 && *cp2 == *cp3) {
			cp2++; cp3++;
		}
		if (*cp2 == '\0') {
			return TRUE;
		}
		cp1--;
	}
	return FALSE;
}

/* returns TRUE at end-of-line */
boolean_t
db_inputchar(int c)
{
	char *sym;
	char *start;
	char *restart;
	jmp_buf_t db_jmpbuf;
	jmp_buf_t *db_prev;
	char *p;
	int len;

	switch(db_completion) {
	case -1:
	    db_putchar('\n');
	    db_prev = db_recover;
	    if (_setjmp(db_recover = &db_jmpbuf) == 0 &&
		(c == 'y' || c == ' ' || c == '\t'))
		    db_print_completion(db_tok_string);
	    db_recover = db_prev;
	    db_completion = 0;
	    db_reset_more();
	    db_output_prompt();
	    if (db_le > db_lbuf_start) {
		    for (start = db_lbuf_start; start < db_le; start++)
			    db_putchar(*start);
		db_putnchars(BACKUP, db_le - db_lc);
	    }
	    return(FALSE);

	case 0:
	    break;

	default:
	    if (c == '\t') {
		db_printf("\nThere are %d possibilities. ", db_completion);
		db_printf("Do you really wish to see them all [n] ? ");
		db_force_whitespace();
		db_completion = -1;
		db_reset_more();
		return(FALSE);
	    }
	    db_completion = 0;
	    break;
	}

	switch (c) {
	    case '\t':
		/* symbol completion */
		if (db_lc == db_lbuf_start || db_auto_completion == 0)
		    break;
		if (db_le == db_lbuf_end) {
		    cnputc('\007');
		    break;
		}
		start = db_lc - 1;
		while (start >= db_lbuf_start &&
		       ((*start >= 'A' && *start <= 'Z') ||
			(*start >= 'a' && *start <= 'z') ||
			(*start >= '0' && *start <= '9') ||
			*start == '_' || *start == ':'))
		    start--;
		if (start == db_lc - 1)
		    break;
		if (start > db_lbuf_start && *start == '$') {
		    cnputc('\007');
		    break;
		}
		sym = db_tok_string;
		restart = ++start;
		do {
		    *sym++ = *start++;
		} while (start != db_lc &&
			 sym != db_tok_string + sizeof(db_tok_string));
		if (sym == db_tok_string + sizeof(db_tok_string)) {
		    cnputc('\007');
		    break;
		}
		*sym = '\0';
		db_completion = db_lookup_incomplete(db_tok_string,
						     sizeof(db_tok_string));
		if (db_completion == 0) {
		    /* symbol unknown */
		    cnputc('\007');
		    break;
		}

		len = strlen(db_tok_string) - (start - restart);
		if (db_completion == 1 &&
		    (db_le == db_lc ||
		     (db_le > db_lc) && *db_lc != ' '))
		    len++;
		for (p = db_le - 1; p >= db_lc; p--)
		    *(p + len) = *p;
		db_le += len;
		for (sym = &db_tok_string[start - restart];
		     *sym != '\0'; sym++)
		    *db_lc++ = *sym;

		if (db_completion == 1 || db_completion > db_auto_completion) {
		    for (sym = &db_tok_string[start - restart];
			 *sym != '\0'; sym++)
			cnputc(*sym);
		    if (db_completion == 1) {
			if (db_le == db_lc ||
			    (db_le > db_lc) && *db_lc != ' ') {
			    cnputc(' ');
			    *db_lc++ = ' ';
			}
			db_completion = 0;
		    }
		    db_putstring(db_lc, db_le - db_lc);
		    db_putnchars(BACKUP, db_le - db_lc);
		}

		if (db_completion > 1) {
		    cnputc('\007');
		    if (db_completion <= db_auto_completion) {
			db_putchar('\n');
			db_print_completion(db_tok_string);
			db_completion = 0;
			db_reset_more();
			db_output_prompt();
			if (db_le > db_lbuf_start) {
			    for (start = db_lbuf_start; start < db_le; start++)
				db_putchar(*start);
			    db_putnchars(BACKUP, db_le - db_lc);
			}
		    }
		}
		break;

	    case CTRL('b'):
		/* back up one character */
		if (db_lc > db_lbuf_start) {
		    cnputc(BACKUP);
		    db_lc--;
		}
		break;
	    case CTRL('f'):
		/* forward one character */
		if (db_lc < db_le) {
		    cnputc(*db_lc);
		    db_lc++;
		}
		break;
	    case CTRL('a'):
		/* beginning of line */
		while (db_lc > db_lbuf_start) {
		    cnputc(BACKUP);
		    db_lc--;
		}
		break;
	    case CTRL('e'):
		/* end of line */
		while (db_lc < db_le) {
		    cnputc(*db_lc);
		    db_lc++;
		}
		break;
	    case CTRL('h'):
	    case 0177:
		/* erase previous character */
		if (db_lc > db_lbuf_start)
		    db_delete(1, DEL_BWD);
		break;
	    case CTRL('d'):
		/* erase next character */
		if (db_lc < db_le)
		    db_delete(1, DEL_FWD);
		break;
	    case CTRL('k'):
		/* delete to end of line */
		if (db_lc < db_le)
		    db_delete(db_le - db_lc, DEL_FWD);
		break;
	    case CTRL('u'):
		/* delete to beginning of line */
		if (db_lc > db_lbuf_start)
		    db_delete(db_lc - db_lbuf_start, DEL_BWD);
		break;
	    case CTRL('t'):
		/* twiddle last 2 characters */
		if (db_lc >= db_lbuf_start + 2) {
		    c = db_lc[-2];
		    db_lc[-2] = db_lc[-1];
		    db_lc[-1] = c;
		    cnputc(BACKUP);
		    cnputc(BACKUP);
		    cnputc(db_lc[-2]);
		    cnputc(db_lc[-1]);
		}
		break;
	    case CTRL('c'):
	    case CTRL('g'):
		db_delete_line();
#if DB_HISTORY_SIZE != 0
		db_history_curr = db_history_last;
		if (c == CTRL('g') && db_hist_search) {
			char *p;
			for (p = db_hist_search_string, db_le = db_lbuf_start;
			     *p; ) {
				*db_le++ = *p++;
			}
			db_lc = db_le;
			*db_le = '\0';
			db_putstring(db_lbuf_start, db_le - db_lbuf_start);
		}
#endif
		break;
#if DB_HISTORY_SIZE != 0
	    case CTRL('r'):
		if (db_hist_search++ == 0) {
			/* starting an history lookup */
			register char *cp1, *cp2;
			for (cp1 = db_lbuf_start, cp2 = db_hist_search_string;
			     cp1 < db_le;
			     cp1++, cp2++)
				*cp2 = *cp1;
			*cp2 = '\0';
			db_hist_search++;
		}
		/* FALL THROUGH */
	    case CTRL('p'):
		{
		char * old_history_curr = db_history_curr;

		if (db_hist_unmodified++ == 0)
			db_hist_unmodified++;
	        DEC_DB_CURR();
	        while (db_history_curr != db_history_last) {
			DEC_DB_CURR();
			if (*db_history_curr == '\0') {
				INC_DB_CURR();
				if (db_hist_search <= 1) {
					if (*db_history_curr == '\0')
						cnputc('\007');
					else
						DEC_DB_CURR();
					break;
				}
				if (*db_history_curr == '\0') {
					cnputc('\007');
					db_history_curr = old_history_curr;
					DEC_DB_CURR();
					break;
				}
				if (db_history_curr != db_history_last &&
				    db_hist_substring(db_history_curr,
						      db_hist_search_string)) {
					DEC_DB_CURR();
					break;
				}
				DEC_DB_CURR();
			}
		}
		if (db_history_curr == db_history_last) {
			cnputc('\007');
			db_history_curr = old_history_curr;
		} else {
			register char *p;
			INC_DB_CURR();
			db_delete_line();
			for (p = db_history_curr, db_le = db_lbuf_start;
			     *p; ) {
				*db_le++ = *p++;
				if (p == db_history + db_history_size) {
					p = db_history;
				}
			}
			db_lc = db_le;
			*db_le = '\0';
			db_putstring(db_lbuf_start, db_le - db_lbuf_start);
		}
		break;
		}
	    case CTRL('s'):
		if (db_hist_search++ == 0) {
			/* starting an history lookup */
			register char *cp1, *cp2;
			for (cp1 = db_lbuf_start, cp2 = db_hist_search_string;
			     cp1 < db_le;
			     cp1++, cp2++)
				*cp2 = *cp1;
			*cp2 = '\0';
			db_hist_search++;
		}
		/* FALL THROUGH */
	    case CTRL('n'):
		{
		char *old_history_curr = db_history_curr;

		if (db_hist_unmodified++ == 0)
			db_hist_unmodified++;
	        while (db_history_curr != db_history_last) {
			if (*db_history_curr == '\0') {
				if (db_hist_search <= 1)
					break;
				INC_DB_CURR();
				if (db_history_curr != db_history_last &&
				    db_hist_substring(db_history_curr,
						      db_hist_search_string)) {
					DEC_DB_CURR();
					break;
				}
				DEC_DB_CURR();
			}
			INC_DB_CURR();
		}
		if (db_history_curr != db_history_last) {
			INC_DB_CURR();
			if (db_history_curr != db_history_last) {
				register char *p;
				db_delete_line();
				for (p = db_history_curr,
				     db_le = db_lbuf_start; *p;) {
					*db_le++ = *p++;
					if (p == db_history +
					    db_history_size) {
						p = db_history;
					}
				}
				db_lc = db_le;
				*db_le = '\0';
				db_putstring(db_lbuf_start,
					     db_le - db_lbuf_start);
			} else {
				cnputc('\007');
				db_history_curr = old_history_curr;
			}
		} else {
			cnputc('\007');
			db_history_curr = old_history_curr;
		}
		break;
		}
#endif
	    /* refresh the command line */
	    case CTRL('l'):
		db_putstring("^L\n", 3);
		if (db_le > db_lbuf_start) {
			db_putstring(db_lbuf_start, db_le - db_lbuf_start);
			db_putnchars(BACKUP, db_le - db_lc);
		}
		break;
	    case '\n':
	    case '\r':
#if DB_HISTORY_SIZE != 0
		/* Check if it same than previous line */
		if (db_history_prev) {
			register char *pp, *pc;

			/* Is it unmodified */
			for (p = db_history_prev, pc = db_lbuf_start;
			     pc != db_le && *p;) {
				if (*p != *pc)
				    break;
				if (++p == db_history + db_history_size) {
					p = db_history;
				}
				if (++pc == db_history + db_history_size) {
					pc = db_history;
				}
			}
			if (!*p && pc == db_le) {
				/* Repeted previous line, not saved */
				db_history_curr = db_history_last;
				*db_le++ = c;
				db_hist_search = 0;
				db_hist_unmodified = 0;
				return (TRUE);
			}
		}
		if (db_le != db_lbuf_start &&
		    (db_hist_unmodified == 0 || !db_hist_ignore_dups)) {
			db_history_prev = db_history_last;
			for (p = db_lbuf_start; p != db_le; p++) {
				*db_history_last++ = *p;
				if (db_history_last == db_history +
				    db_history_size) {
					db_history_last = db_history;
				}
			}
			*db_history_last++ = '\0';
		}
		db_history_curr = db_history_last;
#endif
		*db_le++ = c;
		db_hist_search = 0;
		db_hist_unmodified = 0;
		return (TRUE);
	    default:
		if (db_le == db_lbuf_end) {
		    cnputc('\007');
		}
		else if (c >= ' ' && c <= '~') {
		    for (p = db_le; p > db_lc; p--)
			*p = *(p-1);
		    *db_lc++ = c;
		    db_le++;
		    cnputc(c);
		    db_putstring(db_lc, db_le - db_lc);
		    db_putnchars(BACKUP, db_le - db_lc);
		}
		break;
	}
	if (db_hist_search)
		db_hist_search--;
	if (db_hist_unmodified)
		db_hist_unmodified--;
	return (FALSE);
}

int
db_readline(
	char *	lstart,
	int	lsize)
{
	db_force_whitespace();	/* synch output position */

	db_lbuf_start = lstart;
	db_lbuf_end   = lstart + lsize - 1;
	db_lc = lstart;
	db_le = lstart;

	while (!db_inputchar(cngetc()))
	    continue;

	db_putchar('\n');	/* synch output position */

	*db_le = 0;
	return (db_le - db_lbuf_start);
}

void
db_check_interrupt(void)
{
	register int	c;

	c = cnmaygetc();
	switch (c) {
	    case -1:		/* no character */
		return;

	    case CTRL('c'):
		db_error((char *)0);
		/*NOTREACHED*/

	    case CTRL('s'):
		do {
		    c = cnmaygetc();
		    if (c == CTRL('c'))
			db_error((char *)0);
		} while (c != CTRL('q'));
		break;

	    default:
		/* drop on floor */
		break;
	}
}