FreeBSD/Linux Kernel Cross Reference
sys/ddb/db_input.c
1 /*-
2 * SPDX-License-Identifier: MIT-CMU
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
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 /*
29 * Author: David B. Golub, Carnegie Mellon University
30 * Date: 7/90
31 */
32
33 #include <sys/cdefs.h>
34 __FBSDID("$FreeBSD$");
35
36 #include <sys/param.h>
37 #include <sys/systm.h>
38 #include <sys/cons.h>
39
40 #include <ddb/ddb.h>
41 #include <ddb/db_output.h>
42
43 /*
44 * Character input and editing.
45 */
46
47 /*
48 * We don't track output position while editing input,
49 * since input always ends with a new-line. We just
50 * reset the line position at the end.
51 */
52 static char * db_lbuf_start; /* start of input line buffer */
53 static char * db_lbuf_end; /* end of input line buffer */
54 static char * db_lc; /* current character */
55 static char * db_le; /* one past last character */
56
57 /*
58 * Simple input line history support.
59 */
60 static char db_lhistory[2048];
61 static int db_lhistlsize, db_lhistidx, db_lhistcur;
62 static int db_lhist_nlines;
63
64 #define CTRL(c) ((c) & 0x1f)
65 #define BLANK ' '
66 #define BACKUP '\b'
67
68 static int cnmaygetc(void);
69 static void db_delete(int n, int bwd);
70 static int db_inputchar(int c);
71 static void db_putnchars(int c, int count);
72 static void db_putstring(char *s, int count);
73
74 static void
75 db_putstring(s, count)
76 char *s;
77 int count;
78 {
79 while (--count >= 0)
80 cnputc(*s++);
81 }
82
83 static void
84 db_putnchars(c, count)
85 int c;
86 int count;
87 {
88 while (--count >= 0)
89 cnputc(c);
90 }
91
92 /*
93 * Delete N characters, forward or backward
94 */
95 #define DEL_FWD 0
96 #define DEL_BWD 1
97 static void
98 db_delete(n, bwd)
99 int n;
100 int bwd;
101 {
102 char *p;
103
104 if (bwd) {
105 db_lc -= n;
106 db_putnchars(BACKUP, n);
107 }
108 for (p = db_lc; p < db_le-n; p++) {
109 *p = *(p+n);
110 cnputc(*p);
111 }
112 db_putnchars(BLANK, n);
113 db_putnchars(BACKUP, db_le - db_lc);
114 db_le -= n;
115 }
116
117 /* returns true at end-of-line */
118 static int
119 db_inputchar(c)
120 int c;
121 {
122 static int escstate;
123
124 if (escstate == 1) {
125 /* ESC seen, look for [ or O */
126 if (c == '[' || c == 'O')
127 escstate++;
128 else
129 escstate = 0; /* re-init state machine */
130 return (0);
131 } else if (escstate == 2) {
132 escstate = 0;
133 /*
134 * If a valid cursor key has been found, translate
135 * into an emacs-style control key, and fall through.
136 * Otherwise, drop off.
137 */
138 switch (c) {
139 case 'A': /* up */
140 c = CTRL('p');
141 break;
142 case 'B': /* down */
143 c = CTRL('n');
144 break;
145 case 'C': /* right */
146 c = CTRL('f');
147 break;
148 case 'D': /* left */
149 c = CTRL('b');
150 break;
151 default:
152 return (0);
153 }
154 }
155
156 switch (c) {
157 case CTRL('['):
158 escstate = 1;
159 break;
160 case CTRL('b'):
161 /* back up one character */
162 if (db_lc > db_lbuf_start) {
163 cnputc(BACKUP);
164 db_lc--;
165 }
166 break;
167 case CTRL('f'):
168 /* forward one character */
169 if (db_lc < db_le) {
170 cnputc(*db_lc);
171 db_lc++;
172 }
173 break;
174 case CTRL('a'):
175 /* beginning of line */
176 while (db_lc > db_lbuf_start) {
177 cnputc(BACKUP);
178 db_lc--;
179 }
180 break;
181 case CTRL('e'):
182 /* end of line */
183 while (db_lc < db_le) {
184 cnputc(*db_lc);
185 db_lc++;
186 }
187 break;
188 case CTRL('h'):
189 case 0177:
190 /* erase previous character */
191 if (db_lc > db_lbuf_start)
192 db_delete(1, DEL_BWD);
193 break;
194 case CTRL('d'):
195 /* erase next character */
196 if (db_lc < db_le)
197 db_delete(1, DEL_FWD);
198 break;
199 case CTRL('u'):
200 case CTRL('c'):
201 /* kill entire line: */
202 /* at first, delete to beginning of line */
203 if (db_lc > db_lbuf_start)
204 db_delete(db_lc - db_lbuf_start, DEL_BWD);
205 /* FALLTHROUGH */
206 case CTRL('k'):
207 /* delete to end of line */
208 if (db_lc < db_le)
209 db_delete(db_le - db_lc, DEL_FWD);
210 break;
211 case CTRL('t'):
212 /* twiddle last 2 characters */
213 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 break;
223 case CTRL('w'):
224 /* erase previous word */
225 for (; db_lc > db_lbuf_start;) {
226 if (*(db_lc - 1) != ' ')
227 break;
228 db_delete(1, DEL_BWD);
229 }
230 for (; db_lc > db_lbuf_start;) {
231 if (*(db_lc - 1) == ' ')
232 break;
233 db_delete(1, DEL_BWD);
234 }
235 break;
236 case CTRL('r'):
237 db_putstring("^R\n", 3);
238 redraw:
239 if (db_le > db_lbuf_start) {
240 db_putstring(db_lbuf_start, db_le - db_lbuf_start);
241 db_putnchars(BACKUP, db_le - db_lc);
242 }
243 break;
244 case CTRL('p'):
245 /* Make previous history line the active one. */
246 if (db_lhistcur >= 0) {
247 bcopy(db_lhistory + db_lhistcur * db_lhistlsize,
248 db_lbuf_start, db_lhistlsize);
249 db_lhistcur--;
250 goto hist_redraw;
251 }
252 break;
253 case CTRL('n'):
254 /* Make next history line the active one. */
255 if (db_lhistcur < db_lhistidx - 1) {
256 db_lhistcur += 2;
257 bcopy(db_lhistory + db_lhistcur * db_lhistlsize,
258 db_lbuf_start, db_lhistlsize);
259 } else {
260 /*
261 * ^N through tail of history, reset the
262 * buffer to zero length.
263 */
264 *db_lbuf_start = '\0';
265 db_lhistcur = db_lhistidx;
266 }
267
268 hist_redraw:
269 db_putnchars(BACKUP, db_lc - db_lbuf_start);
270 db_putnchars(BLANK, db_le - db_lbuf_start);
271 db_putnchars(BACKUP, db_le - db_lbuf_start);
272 db_le = strchr(db_lbuf_start, '\0');
273 if (db_le[-1] == '\r' || db_le[-1] == '\n')
274 *--db_le = '\0';
275 db_lc = db_le;
276 goto redraw;
277
278 case -1:
279 /*
280 * eek! the console returned eof.
281 * probably that means we HAVE no console.. we should try bail
282 * XXX
283 */
284 c = '\r';
285 case '\n':
286 /* FALLTHROUGH */
287 case '\r':
288 *db_le++ = c;
289 return (1);
290 default:
291 if (db_le == db_lbuf_end) {
292 cnputc('\007');
293 }
294 else if (c >= ' ' && c <= '~') {
295 char *p;
296
297 for (p = db_le; p > db_lc; p--)
298 *p = *(p-1);
299 *db_lc++ = c;
300 db_le++;
301 cnputc(c);
302 db_putstring(db_lc, db_le - db_lc);
303 db_putnchars(BACKUP, db_le - db_lc);
304 }
305 break;
306 }
307 return (0);
308 }
309
310 static int
311 cnmaygetc()
312 {
313 return (-1);
314 }
315
316 int
317 db_readline(lstart, lsize)
318 char * lstart;
319 int lsize;
320 {
321
322 if (lsize < 2)
323 return (0);
324 if (lsize != db_lhistlsize) {
325 /*
326 * (Re)initialize input line history. Throw away any
327 * existing history.
328 */
329 db_lhist_nlines = sizeof(db_lhistory) / lsize;
330 db_lhistlsize = lsize;
331 db_lhistidx = -1;
332 }
333 db_lhistcur = db_lhistidx;
334
335 db_force_whitespace(); /* synch output position */
336
337 db_lbuf_start = lstart;
338 db_lbuf_end = lstart + lsize - 2; /* Will append NL and NUL. */
339 db_lc = lstart;
340 db_le = lstart;
341
342 while (!db_inputchar(cngetc()))
343 continue;
344
345 db_capture_write(lstart, db_le - db_lbuf_start);
346 db_printf("\n"); /* synch output position */
347 *db_le = 0;
348
349 if (db_le - db_lbuf_start > 1) {
350 /* Maintain input line history for non-empty lines. */
351 if (++db_lhistidx == db_lhist_nlines) {
352 /* Rotate history. */
353 bcopy(db_lhistory + db_lhistlsize, db_lhistory,
354 db_lhistlsize * (db_lhist_nlines - 1));
355 db_lhistidx--;
356 }
357 bcopy(lstart, db_lhistory + db_lhistidx * db_lhistlsize,
358 db_lhistlsize);
359 }
360
361 return (db_le - db_lbuf_start);
362 }
363
364 void
365 db_check_interrupt(void)
366 {
367 int c;
368
369 c = cnmaygetc();
370 switch (c) {
371 case -1: /* no character */
372 return;
373
374 case CTRL('c'):
375 db_error((char *)0);
376 /*NOTREACHED*/
377
378 case CTRL('s'):
379 do {
380 c = cnmaygetc();
381 if (c == CTRL('c'))
382 db_error((char *)0);
383 } while (c != CTRL('q'));
384 break;
385
386 default:
387 /* drop on floor */
388 break;
389 }
390 }
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