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/param.h> 34 #include <sys/systm.h> 35 #include <sys/cons.h> 36 #include <sys/sysctl.h> 37 38 #include <ddb/ddb.h> 39 #include <ddb/db_output.h> 40 41 /* 42 * Character input and editing. 43 */ 44 45 /* 46 * We don't track output position while editing input, 47 * since input always ends with a new-line. We just 48 * reset the line position at the end. 49 */ 50 static char * db_lbuf_start; /* start of input line buffer */ 51 static char * db_lbuf_end; /* end of input line buffer */ 52 static char * db_lc; /* current character */ 53 static char * db_le; /* one past last character */ 54 55 /* 56 * Raw input buffer, processed only for certain control characters. 57 */ 58 #define DB_RAW_SIZE 512 59 static char db_raw[DB_RAW_SIZE]; 60 static u_int db_raw_pos; 61 static u_int db_raw_cnt; 62 static int db_raw_warned; 63 static int ddb_prioritize_control_input = 1; 64 SYSCTL_INT(_debug_ddb, OID_AUTO, prioritize_control_input, CTLFLAG_RWTUN, 65 &ddb_prioritize_control_input, 0, 66 "Drop input when the buffer fills in order to keep servicing ^C/^S/^Q"); 67 68 /* 69 * Simple input line history support. 70 */ 71 static char db_lhistory[2048]; 72 static int db_lhistlsize, db_lhistidx, db_lhistcur; 73 static int db_lhist_nlines; 74 75 #define CTRL(c) ((c) & 0x1f) 76 #define BLANK ' ' 77 #define BACKUP '\b' 78 79 static void db_delete(int n, int bwd); 80 static int db_inputchar(int c); 81 static void db_putnchars(int c, int count); 82 static void db_putstring(char *s, int count); 83 static int db_raw_pop(void); 84 static void db_raw_push(int); 85 static int db_raw_space(void); 86 87 static void 88 db_putstring(char *s, int count) 89 { 90 while (--count >= 0) 91 cnputc(*s++); 92 } 93 94 static void 95 db_putnchars(int c, int count) 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 1 106 static void 107 db_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 } 123 124 /* returns true at end-of-line */ 125 static int 126 db_inputchar(int c) 127 { 128 static int escstate; 129 130 if (escstate == 1) { 131 /* ESC seen, look for [ or O */ 132 if (c == '[' || c == 'O') 133 escstate++; 134 else 135 escstate = 0; /* re-init state machine */ 136 return (0); 137 } else if (escstate == 2) { 138 escstate = 0; 139 /* 140 * If a valid cursor key has been found, translate 141 * into an emacs-style control key, and fall through. 142 * Otherwise, drop off. 143 */ 144 switch (c) { 145 case 'A': /* up */ 146 c = CTRL('p'); 147 break; 148 case 'B': /* down */ 149 c = CTRL('n'); 150 break; 151 case 'C': /* right */ 152 c = CTRL('f'); 153 break; 154 case 'D': /* left */ 155 c = CTRL('b'); 156 break; 157 default: 158 return (0); 159 } 160 } 161 162 switch (c) { 163 case CTRL('['): 164 escstate = 1; 165 break; 166 case CTRL('b'): 167 /* back up one character */ 168 if (db_lc > db_lbuf_start) { 169 cnputc(BACKUP); 170 db_lc--; 171 } 172 break; 173 case CTRL('f'): 174 /* forward one character */ 175 if (db_lc < db_le) { 176 cnputc(*db_lc); 177 db_lc++; 178 } 179 break; 180 case CTRL('a'): 181 /* beginning of line */ 182 while (db_lc > db_lbuf_start) { 183 cnputc(BACKUP); 184 db_lc--; 185 } 186 break; 187 case CTRL('e'): 188 /* end of line */ 189 while (db_lc < db_le) { 190 cnputc(*db_lc); 191 db_lc++; 192 } 193 break; 194 case CTRL('h'): 195 case 0177: 196 /* erase previous character */ 197 if (db_lc > db_lbuf_start) 198 db_delete(1, DEL_BWD); 199 break; 200 case CTRL('d'): 201 /* erase next character */ 202 if (db_lc < db_le) 203 db_delete(1, DEL_FWD); 204 break; 205 case CTRL('u'): 206 case CTRL('c'): 207 /* kill entire line: */ 208 /* at first, delete to beginning of line */ 209 if (db_lc > db_lbuf_start) 210 db_delete(db_lc - db_lbuf_start, DEL_BWD); 211 /* FALLTHROUGH */ 212 case CTRL('k'): 213 /* delete to end of line */ 214 if (db_lc < db_le) 215 db_delete(db_le - db_lc, DEL_FWD); 216 break; 217 case CTRL('t'): 218 /* twiddle last 2 characters */ 219 if (db_lc >= db_lbuf_start + 2) { 220 c = db_lc[-2]; 221 db_lc[-2] = db_lc[-1]; 222 db_lc[-1] = c; 223 cnputc(BACKUP); 224 cnputc(BACKUP); 225 cnputc(db_lc[-2]); 226 cnputc(db_lc[-1]); 227 } 228 break; 229 case CTRL('w'): 230 /* erase previous word */ 231 for (; db_lc > db_lbuf_start;) { 232 if (*(db_lc - 1) != ' ') 233 break; 234 db_delete(1, DEL_BWD); 235 } 236 for (; db_lc > db_lbuf_start;) { 237 if (*(db_lc - 1) == ' ') 238 break; 239 db_delete(1, DEL_BWD); 240 } 241 break; 242 case CTRL('r'): 243 db_putstring("^R\n", 3); 244 redraw: 245 if (db_le > db_lbuf_start) { 246 db_putstring(db_lbuf_start, db_le - db_lbuf_start); 247 db_putnchars(BACKUP, db_le - db_lc); 248 } 249 break; 250 case CTRL('p'): 251 /* Make previous history line the active one. */ 252 if (db_lhistcur >= 0) { 253 bcopy(db_lhistory + db_lhistcur * db_lhistlsize, 254 db_lbuf_start, db_lhistlsize); 255 db_lhistcur--; 256 goto hist_redraw; 257 } 258 break; 259 case CTRL('n'): 260 /* Make next history line the active one. */ 261 if (db_lhistcur < db_lhistidx - 1) { 262 db_lhistcur += 2; 263 bcopy(db_lhistory + db_lhistcur * db_lhistlsize, 264 db_lbuf_start, db_lhistlsize); 265 } else { 266 /* 267 * ^N through tail of history, reset the 268 * buffer to zero length. 269 */ 270 *db_lbuf_start = '\0'; 271 db_lhistcur = db_lhistidx; 272 } 273 274 hist_redraw: 275 db_putnchars(BACKUP, db_lc - db_lbuf_start); 276 db_putnchars(BLANK, db_le - db_lbuf_start); 277 db_putnchars(BACKUP, db_le - db_lbuf_start); 278 db_le = strchr(db_lbuf_start, '\0'); 279 if (db_le[-1] == '\r' || db_le[-1] == '\n') 280 *--db_le = '\0'; 281 db_lc = db_le; 282 goto redraw; 283 284 case -1: 285 /* 286 * eek! the console returned eof. 287 * probably that means we HAVE no console.. we should try bail 288 * XXX 289 */ 290 c = '\r'; 291 case '\n': 292 /* FALLTHROUGH */ 293 case '\r': 294 *db_le++ = c; 295 return (1); 296 default: 297 if (db_le == db_lbuf_end) { 298 cnputc('\007'); 299 } 300 else if (c >= ' ' && c <= '~') { 301 char *p; 302 303 for (p = db_le; p > db_lc; p--) 304 *p = *(p-1); 305 *db_lc++ = c; 306 db_le++; 307 cnputc(c); 308 db_putstring(db_lc, db_le - db_lc); 309 db_putnchars(BACKUP, db_le - db_lc); 310 } 311 break; 312 } 313 return (0); 314 } 315 316 /* Get a character from the console, first checking the raw input buffer. */ 317 int 318 db_getc(void) 319 { 320 int c; 321 322 if (db_raw_cnt == 0) { 323 c = cngetc(); 324 } else { 325 c = db_raw_pop(); 326 if (c == '\r') 327 c = '\n'; 328 } 329 return (c); 330 } 331 332 /* Whether the raw input buffer has space to accept another character. */ 333 static int 334 db_raw_space(void) 335 { 336 337 return (db_raw_cnt < DB_RAW_SIZE); 338 } 339 340 /* Un-get a character from the console by buffering it. */ 341 static void 342 db_raw_push(int c) 343 { 344 345 if (!db_raw_space()) 346 db_error(NULL); 347 db_raw[(db_raw_pos + db_raw_cnt++) % DB_RAW_SIZE] = c; 348 } 349 350 /* Drain a character from the raw input buffer. */ 351 static int 352 db_raw_pop(void) 353 { 354 355 if (db_raw_cnt == 0) 356 return (-1); 357 db_raw_cnt--; 358 db_raw_warned = 0; 359 return (db_raw[db_raw_pos++ % DB_RAW_SIZE]); 360 } 361 362 int 363 db_readline(char *lstart, int lsize) 364 { 365 366 if (lsize < 2) 367 return (0); 368 if (lsize != db_lhistlsize) { 369 /* 370 * (Re)initialize input line history. Throw away any 371 * existing history. 372 */ 373 db_lhist_nlines = sizeof(db_lhistory) / lsize; 374 db_lhistlsize = lsize; 375 db_lhistidx = -1; 376 } 377 db_lhistcur = db_lhistidx; 378 379 db_force_whitespace(); /* synch output position */ 380 381 db_lbuf_start = lstart; 382 db_lbuf_end = lstart + lsize - 2; /* Will append NL and NUL. */ 383 db_lc = lstart; 384 db_le = lstart; 385 386 while (!db_inputchar(db_getc())) 387 continue; 388 389 db_capture_write(lstart, db_le - db_lbuf_start); 390 db_printf("\n"); /* synch output position */ 391 *db_le = 0; 392 393 if (db_le - db_lbuf_start > 1) { 394 /* Maintain input line history for non-empty lines. */ 395 if (++db_lhistidx == db_lhist_nlines) { 396 /* Rotate history. */ 397 bcopy(db_lhistory + db_lhistlsize, db_lhistory, 398 db_lhistlsize * (db_lhist_nlines - 1)); 399 db_lhistidx--; 400 } 401 bcopy(lstart, db_lhistory + db_lhistidx * db_lhistlsize, 402 db_lhistlsize); 403 } 404 405 return (db_le - db_lbuf_start); 406 } 407 408 static void 409 db_do_interrupt(const char *reason) 410 { 411 412 /* Do a pager quit too because some commands have jmpbuf handling. */ 413 db_disable_pager(); 414 db_pager_quit = 1; 415 db_error(reason); 416 } 417 418 void 419 db_check_interrupt(void) 420 { 421 int c; 422 423 /* 424 * Check console input for control characters. Non-control input is 425 * buffered. When buffer space is exhausted, either stop responding to 426 * control input or drop further non-control input on the floor. 427 */ 428 for (;;) { 429 if (!ddb_prioritize_control_input && !db_raw_space()) 430 return; 431 c = cncheckc(); 432 switch (c) { 433 case -1: /* no character */ 434 return; 435 436 case CTRL('c'): 437 db_do_interrupt("^C"); 438 /*NOTREACHED*/ 439 440 case CTRL('s'): 441 do { 442 c = cncheckc(); 443 if (c == CTRL('c')) 444 db_do_interrupt("^C"); 445 } while (c != CTRL('q')); 446 break; 447 448 default: 449 if (db_raw_space()) { 450 db_raw_push(c); 451 } else if (!db_raw_warned) { 452 db_raw_warned = 1; 453 db_printf("\n--Exceeded input buffer--\n"); 454 } 455 break; 456 } 457 } 458 } 459