db_input.c revision 1.25 
1/*	$NetBSD: db_input.c,v 1.25 2010/08/31 07:12:55 enami 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 1.25 2010/08/31 07:12:55 enami 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 char    *db_history_curr = db_history;	/* start of current line */
67static char    *db_history_last = db_history;	/* start of last line */
68static char    *db_history_prev = (char *) 0;	/* start of previous line */
69#endif
70
71
72#define	CTRL(c)		((c) & 0x1f)
73#define	isspace(c)	((c) == ' ' || (c) == '\t')
74#define	BLANK		' '
75#define	BACKUP		'\b'
76
77static int	cnmaygetc(void);
78static void	db_putstring(const char *, int);
79static void	db_putnchars(int, int);
80static void	db_delete(int, int);
81static void	db_delete_line(void);
82static int	db_inputchar(int);
83
84static void
85db_putstring(const char *s, int count)
86{
87
88	while (--count >= 0)
89		cnputc(*s++);
90}
91
92static void
93db_putnchars(int c, int count)
94{
95
96	while (--count >= 0)
97		cnputc(c);
98}
99
100/*
101 * Delete N characters, forward or backward
102 */
103#define	DEL_FWD		0
104#define	DEL_BWD		1
105static void
106db_delete(int n, int bwd)
107{
108	char *p;
109
110	if (bwd) {
111		db_lc -= n;
112		db_putnchars(BACKUP, n);
113	}
114	for (p = db_lc; p < db_le-n; p++) {
115		*p = *(p+n);
116		cnputc(*p);
117	}
118	db_putnchars(BLANK, n);
119	db_putnchars(BACKUP, db_le - db_lc);
120	db_le -= n;
121}
122
123static void
124db_delete_line(void)
125{
126
127	db_delete(db_le - db_lc, DEL_FWD);
128	db_delete(db_lc - db_lbuf_start, DEL_BWD);
129	db_le = db_lc = db_lbuf_start;
130}
131
132#if DDB_HISTORY_SIZE != 0
133
134#define INC_DB_CURR() do {						\
135	++db_history_curr;						\
136	if (db_history_curr > db_history + DDB_HISTORY_SIZE - 1)	\
137		db_history_curr = db_history;				\
138    } while (0)
139#define DEC_DB_CURR() do {						\
140	--db_history_curr;						\
141	if (db_history_curr < db_history)				\
142		db_history_curr = db_history + DDB_HISTORY_SIZE - 1;	\
143    } while (0)
144#endif
145
146static inline void db_hist_put(int c)
147{
148	KASSERT(&db_history[0]  <= db_history_last);
149	KASSERT(db_history_last <= &db_history[DDB_HISTORY_SIZE-1]);
150
151	*db_history_last++ = c;
152
153	if (db_history_last > &db_history[DDB_HISTORY_SIZE-1])
154	    db_history_last = db_history;
155}
156
157
158/* returns true at end-of-line */
159static int
160db_inputchar(int c)
161{
162	switch (c) {
163	case CTRL('b'):
164		/* back up one character */
165		if (db_lc > db_lbuf_start) {
166			cnputc(BACKUP);
167			db_lc--;
168		}
169		break;
170	case CTRL('f'):
171		/* forward one character */
172		if (db_lc < db_le) {
173			cnputc(*db_lc);
174			db_lc++;
175		}
176		break;
177	case CTRL('a'):
178		/* beginning of line */
179		while (db_lc > db_lbuf_start) {
180			cnputc(BACKUP);
181			db_lc--;
182		}
183		break;
184	case CTRL('e'):
185		/* end of line */
186		while (db_lc < db_le) {
187			cnputc(*db_lc);
188			db_lc++;
189		}
190		break;
191	case CTRL('h'):
192	case 0177:
193		/* erase previous character */
194		if (db_lc > db_lbuf_start)
195			db_delete(1, DEL_BWD);
196		break;
197	case CTRL('d'):
198		/* erase next character */
199		if (db_lc < db_le)
200			db_delete(1, DEL_FWD);
201		break;
202	case CTRL('k'):
203		/* delete to end of line */
204		if (db_lc < db_le)
205			db_delete(db_le - db_lc, DEL_FWD);
206		break;
207	case CTRL('u'):
208		/* delete line */
209		db_delete_line();
210		break;
211	case CTRL('t'):
212		/* twiddle last 2 characters */
213		if (db_lc >= db_lbuf_start + 1) {
214			if (db_lc < db_le) {
215				c = db_lc[-1];
216				db_lc[-1] = db_lc[0];
217				db_lc[0] = c;
218				cnputc(BACKUP);
219				cnputc(db_lc[-1]);
220				cnputc(db_lc[0]);
221				db_lc++;
222			} else if (db_lc >= db_lbuf_start + 2) {
223				c = db_lc[-2];
224				db_lc[-2] = db_lc[-1];
225				db_lc[-1] = c;
226				cnputc(BACKUP);
227				cnputc(BACKUP);
228				cnputc(db_lc[-2]);
229				cnputc(db_lc[-1]);
230			}
231		}
232		break;
233#if DDB_HISTORY_SIZE != 0
234	case CTRL('p'):
235		DEC_DB_CURR();
236		while (db_history_curr != db_history_last) {
237			DEC_DB_CURR();
238			if (*db_history_curr == '\0')
239				break;
240		}
241		db_delete_line();
242		if (db_history_curr == db_history_last) {
243			INC_DB_CURR();
244			db_le = db_lc = db_lbuf_start;
245		} else {
246			char *p;
247			INC_DB_CURR();
248			for (p = db_history_curr, db_le = db_lbuf_start;
249			     *p; ) {
250				*db_le++ = *p++;
251				if (p >= db_history + DDB_HISTORY_SIZE) {
252					p = db_history;
253				}
254			}
255			db_lc = db_le;
256		}
257		db_putstring(db_lbuf_start, db_le - db_lbuf_start);
258		break;
259	case CTRL('n'):
260		while (db_history_curr != db_history_last) {
261			if (*db_history_curr == '\0')
262				break;
263			INC_DB_CURR();
264		}
265		if (db_history_curr != db_history_last) {
266			INC_DB_CURR();
267			db_delete_line();
268			if (db_history_curr != db_history_last) {
269				char *p;
270				for (p = db_history_curr,
271				     db_le = db_lbuf_start; *p;) {
272					*db_le++ = *p++;
273					if (p >= db_history + DDB_HISTORY_SIZE) {
274						p = db_history;
275					}
276				}
277				db_lc = db_le;
278			}
279			db_putstring(db_lbuf_start, db_le - db_lbuf_start);
280		}
281		break;
282#endif
283	case CTRL('r'):
284		db_putstring("^R\n", 3);
285		if (db_le > db_lbuf_start) {
286			db_putstring(db_lbuf_start, db_le - db_lbuf_start);
287			db_putnchars(BACKUP, db_le - db_lc);
288		}
289		break;
290	case '\n':
291	case '\r':
292#if DDB_HISTORY_SIZE != 0
293		/* Check if it same than previous line */
294		if (db_history_curr == db_history_prev) {
295			char *pp, *pc;
296
297			/* Is it unmodified */
298			for (pp = db_history_prev, pc = db_lbuf_start;
299			     pc != db_le && *pp; pp++, pc++) {
300				if (*pp != *pc)
301					break;
302				if (++pp >= db_history + DDB_HISTORY_SIZE) {
303					pp = db_history;
304				}
305				if (++pc >= db_history + DDB_HISTORY_SIZE) {
306					pc = db_history;
307				}
308			}
309			if (!*pp && pc == db_le) {
310				/* Repeted previous line, not saved */
311				db_history_curr = db_history_last;
312				*db_le++ = c;
313				return (true);
314			}
315		}
316		if (db_le != db_lbuf_start) {
317			char *p;
318
319			db_history_prev = db_history_last;
320
321			for (p = db_lbuf_start; p != db_le; ) {
322				db_hist_put(*p++);
323			}
324			db_hist_put(0);
325		}
326		db_history_curr = db_history_last;
327#endif
328		*db_le++ = c;
329		return (1);
330	default:
331		if (db_le == db_lbuf_end) {
332			cnputc('\007');
333		}
334		else if (c >= ' ' && c <= '~') {
335			char *p;
336
337			for (p = db_le; p > db_lc; p--)
338				*p = *(p-1);
339			*db_lc++ = c;
340			db_le++;
341			cnputc(c);
342			db_putstring(db_lc, db_le - db_lc);
343			db_putnchars(BACKUP, db_le - db_lc);
344		}
345		break;
346	}
347	return (0);
348}
349
350int
351db_readline(char *lstart, int lsize)
352{
353
354# ifdef MULTIPROCESSOR
355	db_printf("db{%ld}> ", (long)cpu_number());
356# else
357	db_printf("db> ");
358# endif
359	db_force_whitespace();	/* synch output position */
360
361	db_lbuf_start = lstart;
362	db_lbuf_end   = lstart + lsize;
363	db_lc = lstart;
364	db_le = lstart;
365
366	while (!db_inputchar(cngetc()))
367		continue;
368
369	db_putchar('\n');	/* synch output position */
370
371	*db_le = 0;
372	return (db_le - db_lbuf_start);
373}
374
375void
376db_check_interrupt(void)
377{
378	int	c;
379
380	c = cnmaygetc();
381	switch (c) {
382	case -1:		/* no character */
383		return;
384
385	case CTRL('c'):
386		db_error((char *)0);
387		/*NOTREACHED*/
388
389	case CTRL('s'):
390		do {
391			c = cnmaygetc();
392			if (c == CTRL('c')) {
393				db_error((char *)0);
394				/*NOTREACHED*/
395			}
396		} while (c != CTRL('q'));
397		break;
398
399	default:
400		/* drop on floor */
401		break;
402	}
403}
404
405static int
406cnmaygetc(void)
407{
408
409	return (-1);
410}
411