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