db_input.c revision 1.23 
1/*	$NetBSD: db_input.c,v 1.23 2009/03/07 22:02:17 ad Exp $	*/
2
3/*
4 * Mach Operating System
5 * Copyright (c) 1991,1990 Carnegie Mellon University
6 * All Rights Reserved.
7 *
8 * Permission to use, copy, modify and distribute this software and its
9 * documentation is hereby granted, provided that both the copyright
10 * notice and this permission notice appear in all copies of the
11 * software, derivative works or modified versions, and any portions
12 * thereof, and that both notices appear in supporting documentation.
13 *
14 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
15 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
16 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
17 *
18 * Carnegie Mellon requests users of this software to return to
19 *
20 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
21 *  School of Computer Science
22 *  Carnegie Mellon University
23 *  Pittsburgh PA 15213-3890
24 *
25 * any improvements or extensions that they make and grant Carnegie the
26 * rights to redistribute these changes.
27 *
28 *	Author: David B. Golub, Carnegie Mellon University
29 *	Date:	7/90
30 */
31
32#include <sys/cdefs.h>
33__KERNEL_RCSID(0, "$NetBSD: db_input.c,v 1.23 2009/03/07 22:02:17 ad Exp $");
34
35#ifdef _KERNEL_OPT
36#include "opt_ddbparam.h"
37#endif
38
39#include <sys/param.h>
40#include <sys/proc.h>
41#include <sys/cpu.h>
42
43#include <ddb/ddb.h>
44
45#include <dev/cons.h>
46
47#ifndef DDB_HISTORY_SIZE
48#define DDB_HISTORY_SIZE 0
49#endif /* DDB_HISTORY_SIZE */
50
51/*
52 * Character input and editing.
53 */
54
55/*
56 * We don't track output position while editing input,
57 * since input always ends with a new-line.  We just
58 * reset the line position at the end.
59 */
60static char    *db_lbuf_start;	/* start of input line buffer */
61static char    *db_lbuf_end;	/* end of input line buffer */
62static char    *db_lc;		/* current character */
63static char    *db_le;		/* one past last character */
64#if DDB_HISTORY_SIZE != 0
65static char	db_history[DDB_HISTORY_SIZE];	/* start of history buffer */
66static int	db_history_size = DDB_HISTORY_SIZE;/* size of history buffer */
67static char    *db_history_curr = db_history;	/* start of current line */
68static char    *db_history_last = db_history;	/* start of last line */
69static char    *db_history_prev = (char *) 0;	/* start of previous line */
70#endif
71
72
73#define	CTRL(c)		((c) & 0x1f)
74#define	isspace(c)	((c) == ' ' || (c) == '\t')
75#define	BLANK		' '
76#define	BACKUP		'\b'
77
78static int	cnmaygetc(void);
79static void	db_putstring(const char *, int);
80static void	db_putnchars(int, int);
81static void	db_delete(int, int);
82static void	db_delete_line(void);
83static int	db_inputchar(int);
84
85static void
86db_putstring(const char *s, int count)
87{
88
89	while (--count >= 0)
90		cnputc(*s++);
91}
92
93static void
94db_putnchars(int c, int count)
95{
96
97	while (--count >= 0)
98		cnputc(c);
99}
100
101/*
102 * Delete N characters, forward or backward
103 */
104#define	DEL_FWD		0
105#define	DEL_BWD		1
106static void
107db_delete(int n, int bwd)
108{
109	char *p;
110
111	if (bwd) {
112		db_lc -= n;
113		db_putnchars(BACKUP, n);
114	}
115	for (p = db_lc; p < db_le-n; p++) {
116		*p = *(p+n);
117		cnputc(*p);
118	}
119	db_putnchars(BLANK, n);
120	db_putnchars(BACKUP, db_le - db_lc);
121	db_le -= n;
122}
123
124static void
125db_delete_line(void)
126{
127
128	db_delete(db_le - db_lc, DEL_FWD);
129	db_delete(db_lc - db_lbuf_start, DEL_BWD);
130	db_le = db_lc = db_lbuf_start;
131}
132
133#if DDB_HISTORY_SIZE != 0
134#define INC_DB_CURR() \
135	do { \
136		 db_history_curr++; \
137		 if (db_history_curr > db_history + db_history_size - 1) \
138			 db_history_curr = db_history; \
139	} while (/*CONSTCOND*/ 0)
140#define DEC_DB_CURR() \
141	do { \
142		 db_history_curr--; \
143		 if (db_history_curr < db_history) \
144		     db_history_curr = db_history + \
145		     db_history_size - 1; \
146	} while (/*CONSTCOND*/ 0)
147#endif
148
149/* returns true at end-of-line */
150static int
151db_inputchar(int c)
152{
153	switch (c) {
154	case CTRL('b'):
155		/* back up one character */
156		if (db_lc > db_lbuf_start) {
157			cnputc(BACKUP);
158			db_lc--;
159		}
160		break;
161	case CTRL('f'):
162		/* forward one character */
163		if (db_lc < db_le) {
164			cnputc(*db_lc);
165			db_lc++;
166		}
167		break;
168	case CTRL('a'):
169		/* beginning of line */
170		while (db_lc > db_lbuf_start) {
171			cnputc(BACKUP);
172			db_lc--;
173		}
174		break;
175	case CTRL('e'):
176		/* end of line */
177		while (db_lc < db_le) {
178			cnputc(*db_lc);
179			db_lc++;
180		}
181		break;
182	case CTRL('h'):
183	case 0177:
184		/* erase previous character */
185		if (db_lc > db_lbuf_start)
186			db_delete(1, DEL_BWD);
187		break;
188	case CTRL('d'):
189		/* erase next character */
190		if (db_lc < db_le)
191			db_delete(1, DEL_FWD);
192		break;
193	case CTRL('k'):
194		/* delete to end of line */
195		if (db_lc < db_le)
196			db_delete(db_le - db_lc, DEL_FWD);
197		break;
198	case CTRL('u'):
199		/* delete line */
200		db_delete_line();
201		break;
202	case CTRL('t'):
203		/* twiddle last 2 characters */
204		if (db_lc >= db_lbuf_start + 1) {
205			if (db_lc < db_le) {
206				c = db_lc[-1];
207				db_lc[-1] = db_lc[0];
208				db_lc[0] = c;
209				cnputc(BACKUP);
210				cnputc(db_lc[-1]);
211				cnputc(db_lc[0]);
212				db_lc++;
213			} else if (db_lc >= db_lbuf_start + 2) {
214				c = db_lc[-2];
215				db_lc[-2] = db_lc[-1];
216				db_lc[-1] = c;
217				cnputc(BACKUP);
218				cnputc(BACKUP);
219				cnputc(db_lc[-2]);
220				cnputc(db_lc[-1]);
221			}
222		}
223		break;
224#if DDB_HISTORY_SIZE != 0
225	case CTRL('p'):
226		DEC_DB_CURR();
227		while (db_history_curr != db_history_last) {
228			DEC_DB_CURR();
229			if (*db_history_curr == '\0')
230				break;
231		}
232		db_delete_line();
233		if (db_history_curr == db_history_last) {
234			INC_DB_CURR();
235			db_le = db_lc = db_lbuf_start;
236		} else {
237			char *p;
238			INC_DB_CURR();
239			for (p = db_history_curr, db_le = db_lbuf_start;
240			     *p; ) {
241				*db_le++ = *p++;
242				if (p == db_history + db_history_size) {
243					p = db_history;
244				}
245			}
246			db_lc = db_le;
247		}
248		db_putstring(db_lbuf_start, db_le - db_lbuf_start);
249		break;
250	case CTRL('n'):
251		while (db_history_curr != db_history_last) {
252			if (*db_history_curr == '\0')
253				break;
254			INC_DB_CURR();
255		}
256		if (db_history_curr != db_history_last) {
257			INC_DB_CURR();
258			db_delete_line();
259			if (db_history_curr != db_history_last) {
260				char *p;
261				for (p = db_history_curr,
262				     db_le = db_lbuf_start; *p;) {
263					*db_le++ = *p++;
264					if (p == db_history +
265					    db_history_size) {
266						p = db_history;
267					}
268				}
269				db_lc = db_le;
270			}
271			db_putstring(db_lbuf_start, db_le - db_lbuf_start);
272		}
273		break;
274#endif
275	case CTRL('r'):
276		db_putstring("^R\n", 3);
277		if (db_le > db_lbuf_start) {
278			db_putstring(db_lbuf_start, db_le - db_lbuf_start);
279			db_putnchars(BACKUP, db_le - db_lc);
280		}
281		break;
282	case '\n':
283	case '\r':
284#if DDB_HISTORY_SIZE != 0
285		/* Check if it same than previous line */
286		if (db_history_curr == db_history_prev) {
287			char *pp, *pc;
288
289			/* Is it unmodified */
290			for (pp = db_history_prev, pc = db_lbuf_start;
291			     pc != db_le && *pp; pp++, pc++) {
292				if (*pp != *pc)
293					break;
294				if (++pp == db_history + db_history_size) {
295					pp = db_history;
296				}
297				if (++pc == db_history + db_history_size) {
298					pc = db_history;
299				}
300			}
301			if (!*pp && pc == db_le) {
302				/* Repeted previous line, not saved */
303				db_history_curr = db_history_last;
304				*db_le++ = c;
305				return (true);
306			}
307		}
308		if (db_le != db_lbuf_start) {
309			char *p;
310			db_history_prev = db_history_last;
311			for (p = db_lbuf_start; p != db_le; p++) {
312				*db_history_last++ = *p;
313				if (db_history_last == db_history +
314				    db_history_size) {
315					db_history_last = db_history;
316				}
317			}
318			*db_history_last++ = '\0';
319		}
320		db_history_curr = db_history_last;
321#endif
322		*db_le++ = c;
323		return (1);
324	default:
325		if (db_le == db_lbuf_end) {
326			cnputc('\007');
327		}
328		else if (c >= ' ' && c <= '~') {
329			char *p;
330
331			for (p = db_le; p > db_lc; p--)
332				*p = *(p-1);
333			*db_lc++ = c;
334			db_le++;
335			cnputc(c);
336			db_putstring(db_lc, db_le - db_lc);
337			db_putnchars(BACKUP, db_le - db_lc);
338		}
339		break;
340	}
341	return (0);
342}
343
344int
345db_readline(char *lstart, int lsize)
346{
347
348# ifdef MULTIPROCESSOR
349	db_printf("db{%ld}> ", (long)cpu_number());
350# else
351	db_printf("db> ");
352# endif
353	db_force_whitespace();	/* synch output position */
354
355	db_lbuf_start = lstart;
356	db_lbuf_end   = lstart + lsize;
357	db_lc = lstart;
358	db_le = lstart;
359
360	while (!db_inputchar(cngetc()))
361		continue;
362
363	db_putchar('\n');	/* synch output position */
364
365	*db_le = 0;
366	return (db_le - db_lbuf_start);
367}
368
369void
370db_check_interrupt(void)
371{
372	int	c;
373
374	c = cnmaygetc();
375	switch (c) {
376	case -1:		/* no character */
377		return;
378
379	case CTRL('c'):
380		db_error((char *)0);
381		/*NOTREACHED*/
382
383	case CTRL('s'):
384		do {
385			c = cnmaygetc();
386			if (c == CTRL('c')) {
387				db_error((char *)0);
388				/*NOTREACHED*/
389			}
390		} while (c != CTRL('q'));
391		break;
392
393	default:
394		/* drop on floor */
395		break;
396	}
397}
398
399static int
400cnmaygetc(void)
401{
402
403	return (-1);
404}
405