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 #include <sys/param.h> 35 #include <sys/systm.h> 36 #include <sys/cons.h> 37 #include <sys/sysctl.h> 38 39 #include <ddb/ddb.h> 40 #include <ddb/db_output.h> 41 42 /* 43 * Character input and editing. 44 */ 45 46 /* 47 * We don't track output position while editing input, 48 * since input always ends with a new-line. We just 49 * reset the line position at the end. 50 */ 51 static char * db_lbuf_start; /* start of input line buffer */ 52 static char * db_lbuf_end; /* end of input line buffer */ 53 static char * db_lc; /* current character */ 54 static char * db_le; /* one past last character */ 55 56 /* 57 * Raw input buffer, processed only for certain control characters. 58 */ 59 #define DB_RAW_SIZE 512 60 static char db_raw[DB_RAW_SIZE]; 61 static u_int db_raw_pos; 62 static u_int db_raw_cnt; 63 static int db_raw_warned; 64 static int ddb_prioritize_control_input = 1; 65 SYSCTL_INT(_debug_ddb, OID_AUTO, prioritize_control_input, CTLFLAG_RWTUN, 66 &ddb_prioritize_control_input, 0, 67 "Drop input when the buffer fills in order to keep servicing ^C/^S/^Q"); 68 69 /* 70 * Simple input line history support. 71 */ 72 static char db_lhistory[2048]; 73 static int db_lhistlsize, db_lhistidx, db_lhistcur; 74 static int db_lhist_nlines; 75 76 #define CTRL(c) ((c) & 0x1f) 77 #define BLANK ' ' 78 #define BACKUP '\b' 79 80 static void db_delete(int n, int bwd); 81 static int db_inputchar(int c); 82 static void db_putnchars(int c, int count); 83 static void db_putstring(char *s, int count); 84 static int db_raw_pop(void); 85 static void db_raw_push(int); 86 static int db_raw_space(void); 87 88 static void 89 db_putstring(char *s, int count) 90 { 91 while (--count >= 0) 92 cnputc(*s++); 93 } 94 95 static void 96 db_putnchars(int c, int count) 97 { 98 while (--count >= 0) 99 cnputc(c); 100 } 101 102 /* 103 * Delete N characters, forward or backward 104 */ 105 #define DEL_FWD 0 106 #define DEL_BWD 1 107 static void 108 db_delete(int n, int bwd) 109 { 110 char *p; 111 112 if (bwd) { 113 db_lc -= n; 114 db_putnchars(BACKUP, n); 115 } 116 for (p = db_lc; p < db_le-n; p++) { 117 *p = *(p+n); 118 cnputc(*p); 119 } 120 db_putnchars(BLANK, n); 121 db_putnchars(BACKUP, db_le - db_lc); 122 db_le -= n; 123 } 124 125 /* returns true at end-of-line */ 126 static int 127 db_inputchar(int c) 128 { 129 static int escstate; 130 131 if (escstate == 1) { 132 /* ESC seen, look for [ or O */ 133 if (c == '[' || c == 'O') 134 escstate++; 135 else 136 escstate = 0; /* re-init state machine */ 137 return (0); 138 } else if (escstate == 2) { 139 escstate = 0; 140 /* 141 * If a valid cursor key has been found, translate 142 * into an emacs-style control key, and fall through. 143 * Otherwise, drop off. 144 */ 145 switch (c) { 146 case 'A': /* up */ 147 c = CTRL('p'); 148 break; 149 case 'B': /* down */ 150 c = CTRL('n'); 151 break; 152 case 'C': /* right */ 153 c = CTRL('f'); 154 break; 155 case 'D': /* left */ 156 c = CTRL('b'); 157 break; 158 default: 159 return (0); 160 } 161 } 162 163 switch (c) { 164 case CTRL('['): 165 escstate = 1; 166 break; 167 case CTRL('b'): 168 /* back up one character */ 169 if (db_lc > db_lbuf_start) { 170 cnputc(BACKUP); 171 db_lc--; 172 } 173 break; 174 case CTRL('f'): 175 /* forward one character */ 176 if (db_lc < db_le) { 177 cnputc(*db_lc); 178 db_lc++; 179 } 180 break; 181 case CTRL('a'): 182 /* beginning of line */ 183 while (db_lc > db_lbuf_start) { 184 cnputc(BACKUP); 185 db_lc--; 186 } 187 break; 188 case CTRL('e'): 189 /* end of line */ 190 while (db_lc < db_le) { 191 cnputc(*db_lc); 192 db_lc++; 193 } 194 break; 195 case CTRL('h'): 196 case 0177: 197 /* erase previous character */ 198 if (db_lc > db_lbuf_start) 199 db_delete(1, DEL_BWD); 200 break; 201 case CTRL('d'): 202 /* erase next character */ 203 if (db_lc < db_le) 204 db_delete(1, DEL_FWD); 205 break; 206 case CTRL('u'): 207 case CTRL('c'): 208 /* kill entire line: */ 209 /* at first, delete to beginning of line */ 210 if (db_lc > db_lbuf_start) 211 db_delete(db_lc - db_lbuf_start, DEL_BWD); 212 /* FALLTHROUGH */ 213 case CTRL('k'): 214 /* delete to end of line */ 215 if (db_lc < db_le) 216 db_delete(db_le - db_lc, DEL_FWD); 217 break; 218 case CTRL('t'): 219 /* twiddle last 2 characters */ 220 if (db_lc >= db_lbuf_start + 2) { 221 c = db_lc[-2]; 222 db_lc[-2] = db_lc[-1]; 223 db_lc[-1] = c; 224 cnputc(BACKUP); 225 cnputc(BACKUP); 226 cnputc(db_lc[-2]); 227 cnputc(db_lc[-1]); 228 } 229 break; 230 case CTRL('w'): 231 /* erase previous word */ 232 for (; db_lc > db_lbuf_start;) { 233 if (*(db_lc - 1) != ' ') 234 break; 235 db_delete(1, DEL_BWD); 236 } 237 for (; db_lc > db_lbuf_start;) { 238 if (*(db_lc - 1) == ' ') 239 break; 240 db_delete(1, DEL_BWD); 241 } 242 break; 243 case CTRL('r'): 244 db_putstring("^R\n", 3); 245 redraw: 246 if (db_le > db_lbuf_start) { 247 db_putstring(db_lbuf_start, db_le - db_lbuf_start); 248 db_putnchars(BACKUP, db_le - db_lc); 249 } 250 break; 251 case CTRL('p'): 252 /* Make previous history line the active one. */ 253 if (db_lhistcur >= 0) { 254 bcopy(db_lhistory + db_lhistcur * db_lhistlsize, 255 db_lbuf_start, db_lhistlsize); 256 db_lhistcur--; 257 goto hist_redraw; 258 } 259 break; 260 case CTRL('n'): 261 /* Make next history line the active one. */ 262 if (db_lhistcur < db_lhistidx - 1) { 263 db_lhistcur += 2; 264 bcopy(db_lhistory + db_lhistcur * db_lhistlsize, 265 db_lbuf_start, db_lhistlsize); 266 } else { 267 /* 268 * ^N through tail of history, reset the 269 * buffer to zero length. 270 */ 271 *db_lbuf_start = '\0'; 272 db_lhistcur = db_lhistidx; 273 } 274 275 hist_redraw: 276 db_putnchars(BACKUP, db_lc - db_lbuf_start); 277 db_putnchars(BLANK, db_le - db_lbuf_start); 278 db_putnchars(BACKUP, db_le - db_lbuf_start); 279 db_le = strchr(db_lbuf_start, '\0'); 280 if (db_le[-1] == '\r' || db_le[-1] == '\n') 281 *--db_le = '\0'; 282 db_lc = db_le; 283 goto redraw; 284 285 case -1: 286 /* 287 * eek! the console returned eof. 288 * probably that means we HAVE no console.. we should try bail 289 * XXX 290 */ 291 c = '\r'; 292 case '\n': 293 /* FALLTHROUGH */ 294 case '\r': 295 *db_le++ = c; 296 return (1); 297 default: 298 if (db_le == db_lbuf_end) { 299 cnputc('\007'); 300 } 301 else if (c >= ' ' && c <= '~') { 302 char *p; 303 304 for (p = db_le; p > db_lc; p--) 305 *p = *(p-1); 306 *db_lc++ = c; 307 db_le++; 308 cnputc(c); 309 db_putstring(db_lc, db_le - db_lc); 310 db_putnchars(BACKUP, db_le - db_lc); 311 } 312 break; 313 } 314 return (0); 315 } 316 317 /* Get a character from the console, first checking the raw input buffer. */ 318 int 319 db_getc(void) 320 { 321 int c; 322 323 if (db_raw_cnt == 0) { 324 c = cngetc(); 325 } else { 326 c = db_raw_pop(); 327 if (c == '\r') 328 c = '\n'; 329 } 330 return (c); 331 } 332 333 /* Whether the raw input buffer has space to accept another character. */ 334 static int 335 db_raw_space(void) 336 { 337 338 return (db_raw_cnt < DB_RAW_SIZE); 339 } 340 341 /* Un-get a character from the console by buffering it. */ 342 static void 343 db_raw_push(int c) 344 { 345 346 if (!db_raw_space()) 347 db_error(NULL); 348 db_raw[(db_raw_pos + db_raw_cnt++) % DB_RAW_SIZE] = c; 349 } 350 351 /* Drain a character from the raw input buffer. */ 352 static int 353 db_raw_pop(void) 354 { 355 356 if (db_raw_cnt == 0) 357 return (-1); 358 db_raw_cnt--; 359 db_raw_warned = 0; 360 return (db_raw[db_raw_pos++ % DB_RAW_SIZE]); 361 } 362 363 int 364 db_readline(char *lstart, int lsize) 365 { 366 367 if (lsize < 2) 368 return (0); 369 if (lsize != db_lhistlsize) { 370 /* 371 * (Re)initialize input line history. Throw away any 372 * existing history. 373 */ 374 db_lhist_nlines = sizeof(db_lhistory) / lsize; 375 db_lhistlsize = lsize; 376 db_lhistidx = -1; 377 } 378 db_lhistcur = db_lhistidx; 379 380 db_force_whitespace(); /* synch output position */ 381 382 db_lbuf_start = lstart; 383 db_lbuf_end = lstart + lsize - 2; /* Will append NL and NUL. */ 384 db_lc = lstart; 385 db_le = lstart; 386 387 while (!db_inputchar(db_getc())) 388 continue; 389 390 db_capture_write(lstart, db_le - db_lbuf_start); 391 db_printf("\n"); /* synch output position */ 392 *db_le = 0; 393 394 if (db_le - db_lbuf_start > 1) { 395 /* Maintain input line history for non-empty lines. */ 396 if (++db_lhistidx == db_lhist_nlines) { 397 /* Rotate history. */ 398 bcopy(db_lhistory + db_lhistlsize, db_lhistory, 399 db_lhistlsize * (db_lhist_nlines - 1)); 400 db_lhistidx--; 401 } 402 bcopy(lstart, db_lhistory + db_lhistidx * db_lhistlsize, 403 db_lhistlsize); 404 } 405 406 return (db_le - db_lbuf_start); 407 } 408 409 static void 410 db_do_interrupt(const char *reason) 411 { 412 413 /* Do a pager quit too because some commands have jmpbuf handling. */ 414 db_disable_pager(); 415 db_pager_quit = 1; 416 db_error(reason); 417 } 418 419 void 420 db_check_interrupt(void) 421 { 422 int c; 423 424 /* 425 * Check console input for control characters. Non-control input is 426 * buffered. When buffer space is exhausted, either stop responding to 427 * control input or drop further non-control input on the floor. 428 */ 429 for (;;) { 430 if (!ddb_prioritize_control_input && !db_raw_space()) 431 return; 432 c = cncheckc(); 433 switch (c) { 434 case -1: /* no character */ 435 return; 436 437 case CTRL('c'): 438 db_do_interrupt("^C"); 439 /*NOTREACHED*/ 440 441 case CTRL('s'): 442 do { 443 c = cncheckc(); 444 if (c == CTRL('c')) 445 db_do_interrupt("^C"); 446 } while (c != CTRL('q')); 447 break; 448 449 default: 450 if (db_raw_space()) { 451 db_raw_push(c); 452 } else if (!db_raw_warned) { 453 db_raw_warned = 1; 454 db_printf("\n--Exceeded input buffer--\n"); 455 } 456 break; 457 } 458 } 459 } 460