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 #include <sys/sysctl.h> 40 41 #include <ddb/ddb.h> 42 #include <ddb/db_output.h> 43 44 /* 45 * Character input and editing. 46 */ 47 48 /* 49 * We don't track output position while editing input, 50 * since input always ends with a new-line. We just 51 * reset the line position at the end. 52 */ 53 static char * db_lbuf_start; /* start of input line buffer */ 54 static char * db_lbuf_end; /* end of input line buffer */ 55 static char * db_lc; /* current character */ 56 static char * db_le; /* one past last character */ 57 58 /* 59 * Raw input buffer, processed only for certain control characters. 60 */ 61 #define DB_RAW_SIZE 512 62 static char db_raw[DB_RAW_SIZE]; 63 static u_int db_raw_pos; 64 static u_int db_raw_cnt; 65 static int db_raw_warned; 66 static int ddb_prioritize_control_input = 1; 67 SYSCTL_INT(_debug_ddb, OID_AUTO, prioritize_control_input, CTLFLAG_RWTUN, 68 &ddb_prioritize_control_input, 0, 69 "Drop input when the buffer fills in order to keep servicing ^C/^S/^Q"); 70 71 /* 72 * Simple input line history support. 73 */ 74 static char db_lhistory[2048]; 75 static int db_lhistlsize, db_lhistidx, db_lhistcur; 76 static int db_lhist_nlines; 77 78 #define CTRL(c) ((c) & 0x1f) 79 #define BLANK ' ' 80 #define BACKUP '\b' 81 82 static void db_delete(int n, int bwd); 83 static int db_inputchar(int c); 84 static void db_putnchars(int c, int count); 85 static void db_putstring(char *s, int count); 86 static int db_raw_pop(void); 87 static void db_raw_push(int); 88 static int db_raw_space(void); 89 90 static void 91 db_putstring(s, count) 92 char *s; 93 int count; 94 { 95 while (--count >= 0) 96 cnputc(*s++); 97 } 98 99 static void 100 db_putnchars(c, count) 101 int c; 102 int count; 103 { 104 while (--count >= 0) 105 cnputc(c); 106 } 107 108 /* 109 * Delete N characters, forward or backward 110 */ 111 #define DEL_FWD 0 112 #define DEL_BWD 1 113 static void 114 db_delete(n, bwd) 115 int n; 116 int bwd; 117 { 118 char *p; 119 120 if (bwd) { 121 db_lc -= n; 122 db_putnchars(BACKUP, n); 123 } 124 for (p = db_lc; p < db_le-n; p++) { 125 *p = *(p+n); 126 cnputc(*p); 127 } 128 db_putnchars(BLANK, n); 129 db_putnchars(BACKUP, db_le - db_lc); 130 db_le -= n; 131 } 132 133 /* returns true at end-of-line */ 134 static int 135 db_inputchar(c) 136 int c; 137 { 138 static int escstate; 139 140 if (escstate == 1) { 141 /* ESC seen, look for [ or O */ 142 if (c == '[' || c == 'O') 143 escstate++; 144 else 145 escstate = 0; /* re-init state machine */ 146 return (0); 147 } else if (escstate == 2) { 148 escstate = 0; 149 /* 150 * If a valid cursor key has been found, translate 151 * into an emacs-style control key, and fall through. 152 * Otherwise, drop off. 153 */ 154 switch (c) { 155 case 'A': /* up */ 156 c = CTRL('p'); 157 break; 158 case 'B': /* down */ 159 c = CTRL('n'); 160 break; 161 case 'C': /* right */ 162 c = CTRL('f'); 163 break; 164 case 'D': /* left */ 165 c = CTRL('b'); 166 break; 167 default: 168 return (0); 169 } 170 } 171 172 switch (c) { 173 case CTRL('['): 174 escstate = 1; 175 break; 176 case CTRL('b'): 177 /* back up one character */ 178 if (db_lc > db_lbuf_start) { 179 cnputc(BACKUP); 180 db_lc--; 181 } 182 break; 183 case CTRL('f'): 184 /* forward one character */ 185 if (db_lc < db_le) { 186 cnputc(*db_lc); 187 db_lc++; 188 } 189 break; 190 case CTRL('a'): 191 /* beginning of line */ 192 while (db_lc > db_lbuf_start) { 193 cnputc(BACKUP); 194 db_lc--; 195 } 196 break; 197 case CTRL('e'): 198 /* end of line */ 199 while (db_lc < db_le) { 200 cnputc(*db_lc); 201 db_lc++; 202 } 203 break; 204 case CTRL('h'): 205 case 0177: 206 /* erase previous character */ 207 if (db_lc > db_lbuf_start) 208 db_delete(1, DEL_BWD); 209 break; 210 case CTRL('d'): 211 /* erase next character */ 212 if (db_lc < db_le) 213 db_delete(1, DEL_FWD); 214 break; 215 case CTRL('u'): 216 case CTRL('c'): 217 /* kill entire line: */ 218 /* at first, delete to beginning of line */ 219 if (db_lc > db_lbuf_start) 220 db_delete(db_lc - db_lbuf_start, DEL_BWD); 221 /* FALLTHROUGH */ 222 case CTRL('k'): 223 /* delete to end of line */ 224 if (db_lc < db_le) 225 db_delete(db_le - db_lc, DEL_FWD); 226 break; 227 case CTRL('t'): 228 /* twiddle last 2 characters */ 229 if (db_lc >= db_lbuf_start + 2) { 230 c = db_lc[-2]; 231 db_lc[-2] = db_lc[-1]; 232 db_lc[-1] = c; 233 cnputc(BACKUP); 234 cnputc(BACKUP); 235 cnputc(db_lc[-2]); 236 cnputc(db_lc[-1]); 237 } 238 break; 239 case CTRL('w'): 240 /* erase previous word */ 241 for (; db_lc > db_lbuf_start;) { 242 if (*(db_lc - 1) != ' ') 243 break; 244 db_delete(1, DEL_BWD); 245 } 246 for (; db_lc > db_lbuf_start;) { 247 if (*(db_lc - 1) == ' ') 248 break; 249 db_delete(1, DEL_BWD); 250 } 251 break; 252 case CTRL('r'): 253 db_putstring("^R\n", 3); 254 redraw: 255 if (db_le > db_lbuf_start) { 256 db_putstring(db_lbuf_start, db_le - db_lbuf_start); 257 db_putnchars(BACKUP, db_le - db_lc); 258 } 259 break; 260 case CTRL('p'): 261 /* Make previous history line the active one. */ 262 if (db_lhistcur >= 0) { 263 bcopy(db_lhistory + db_lhistcur * db_lhistlsize, 264 db_lbuf_start, db_lhistlsize); 265 db_lhistcur--; 266 goto hist_redraw; 267 } 268 break; 269 case CTRL('n'): 270 /* Make next history line the active one. */ 271 if (db_lhistcur < db_lhistidx - 1) { 272 db_lhistcur += 2; 273 bcopy(db_lhistory + db_lhistcur * db_lhistlsize, 274 db_lbuf_start, db_lhistlsize); 275 } else { 276 /* 277 * ^N through tail of history, reset the 278 * buffer to zero length. 279 */ 280 *db_lbuf_start = '\0'; 281 db_lhistcur = db_lhistidx; 282 } 283 284 hist_redraw: 285 db_putnchars(BACKUP, db_lc - db_lbuf_start); 286 db_putnchars(BLANK, db_le - db_lbuf_start); 287 db_putnchars(BACKUP, db_le - db_lbuf_start); 288 db_le = strchr(db_lbuf_start, '\0'); 289 if (db_le[-1] == '\r' || db_le[-1] == '\n') 290 *--db_le = '\0'; 291 db_lc = db_le; 292 goto redraw; 293 294 case -1: 295 /* 296 * eek! the console returned eof. 297 * probably that means we HAVE no console.. we should try bail 298 * XXX 299 */ 300 c = '\r'; 301 case '\n': 302 /* FALLTHROUGH */ 303 case '\r': 304 *db_le++ = c; 305 return (1); 306 default: 307 if (db_le == db_lbuf_end) { 308 cnputc('\007'); 309 } 310 else if (c >= ' ' && c <= '~') { 311 char *p; 312 313 for (p = db_le; p > db_lc; p--) 314 *p = *(p-1); 315 *db_lc++ = c; 316 db_le++; 317 cnputc(c); 318 db_putstring(db_lc, db_le - db_lc); 319 db_putnchars(BACKUP, db_le - db_lc); 320 } 321 break; 322 } 323 return (0); 324 } 325 326 /* Get a character from the console, first checking the raw input buffer. */ 327 int 328 db_getc(void) 329 { 330 int c; 331 332 if (db_raw_cnt == 0) { 333 c = cngetc(); 334 } else { 335 c = db_raw_pop(); 336 if (c == '\r') 337 c = '\n'; 338 } 339 return (c); 340 } 341 342 /* Whether the raw input buffer has space to accept another character. */ 343 static int 344 db_raw_space(void) 345 { 346 347 return (db_raw_cnt < DB_RAW_SIZE); 348 } 349 350 /* Un-get a character from the console by buffering it. */ 351 static void 352 db_raw_push(int c) 353 { 354 355 if (!db_raw_space()) 356 db_error(NULL); 357 db_raw[(db_raw_pos + db_raw_cnt++) % DB_RAW_SIZE] = c; 358 } 359 360 /* Drain a character from the raw input buffer. */ 361 static int 362 db_raw_pop(void) 363 { 364 365 if (db_raw_cnt == 0) 366 return (-1); 367 db_raw_cnt--; 368 db_raw_warned = 0; 369 return (db_raw[db_raw_pos++ % DB_RAW_SIZE]); 370 } 371 372 int 373 db_readline(lstart, lsize) 374 char * lstart; 375 int lsize; 376 { 377 378 if (lsize < 2) 379 return (0); 380 if (lsize != db_lhistlsize) { 381 /* 382 * (Re)initialize input line history. Throw away any 383 * existing history. 384 */ 385 db_lhist_nlines = sizeof(db_lhistory) / lsize; 386 db_lhistlsize = lsize; 387 db_lhistidx = -1; 388 } 389 db_lhistcur = db_lhistidx; 390 391 db_force_whitespace(); /* synch output position */ 392 393 db_lbuf_start = lstart; 394 db_lbuf_end = lstart + lsize - 2; /* Will append NL and NUL. */ 395 db_lc = lstart; 396 db_le = lstart; 397 398 while (!db_inputchar(db_getc())) 399 continue; 400 401 db_capture_write(lstart, db_le - db_lbuf_start); 402 db_printf("\n"); /* synch output position */ 403 *db_le = 0; 404 405 if (db_le - db_lbuf_start > 1) { 406 /* Maintain input line history for non-empty lines. */ 407 if (++db_lhistidx == db_lhist_nlines) { 408 /* Rotate history. */ 409 bcopy(db_lhistory + db_lhistlsize, db_lhistory, 410 db_lhistlsize * (db_lhist_nlines - 1)); 411 db_lhistidx--; 412 } 413 bcopy(lstart, db_lhistory + db_lhistidx * db_lhistlsize, 414 db_lhistlsize); 415 } 416 417 return (db_le - db_lbuf_start); 418 } 419 420 static void 421 db_do_interrupt(const char *reason) 422 { 423 424 /* Do a pager quit too because some commands have jmpbuf handling. */ 425 db_disable_pager(); 426 db_pager_quit = 1; 427 db_error(reason); 428 } 429 430 void 431 db_check_interrupt(void) 432 { 433 int c; 434 435 /* 436 * Check console input for control characters. Non-control input is 437 * buffered. When buffer space is exhausted, either stop responding to 438 * control input or drop further non-control input on the floor. 439 */ 440 for (;;) { 441 if (!ddb_prioritize_control_input && !db_raw_space()) 442 return; 443 c = cncheckc(); 444 switch (c) { 445 case -1: /* no character */ 446 return; 447 448 case CTRL('c'): 449 db_do_interrupt("^C"); 450 /*NOTREACHED*/ 451 452 case CTRL('s'): 453 do { 454 c = cncheckc(); 455 if (c == CTRL('c')) 456 db_do_interrupt("^C"); 457 } while (c != CTRL('q')); 458 break; 459 460 default: 461 if (db_raw_space()) { 462 db_raw_push(c); 463 } else if (!db_raw_warned) { 464 db_raw_warned = 1; 465 db_printf("\n--Exceeded input buffer--\n"); 466 } 467 break; 468 } 469 } 470 } 471