1 /* $OpenBSD: decode.c,v 1.3 2001/11/19 19:02:14 mpech Exp $ */ 2 3 /* 4 * Copyright (c) 1984,1985,1989,1994,1995 Mark Nudelman 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice in the documentation and/or other materials provided with 14 * the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY 17 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 19 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 22 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR 23 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 24 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE 25 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN 26 * IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29 30 /* 31 * Routines to decode user commands. 32 * 33 * This is all table driven. 34 * A command table is a sequence of command descriptors. 35 * Each command descriptor is a sequence of bytes with the following format: 36 * <c1><c2>...<cN><0><action> 37 * The characters c1,c2,...,cN are the command string; that is, 38 * the characters which the user must type. 39 * It is terminated by a null <0> byte. 40 * The byte after the null byte is the action code associated 41 * with the command string. 42 * If an action byte is OR-ed with A_EXTRA, this indicates 43 * that the option byte is followed by an extra string. 44 * 45 * There may be many command tables. 46 * The first (default) table is built-in. 47 * Other tables are read in from "lesskey" files. 48 * All the tables are linked together and are searched in order. 49 */ 50 51 #include "less.h" 52 #include "cmd.h" 53 #include "lesskey.h" 54 55 extern int erase_char, kill_char; 56 57 /* 58 * Command table is ordered roughly according to expected 59 * frequency of use, so the common commands are near the beginning. 60 */ 61 static unsigned char cmdtable[] = 62 { 63 '\r',0, A_F_LINE, 64 '\n',0, A_F_LINE, 65 'e',0, A_F_LINE, 66 'j',0, A_F_LINE, 67 CONTROL('E'),0, A_F_LINE, 68 CONTROL('N'),0, A_F_LINE, 69 'k',0, A_B_LINE, 70 'y',0, A_B_LINE, 71 CONTROL('Y'),0, A_B_LINE, 72 CONTROL('K'),0, A_B_LINE, 73 CONTROL('P'),0, A_B_LINE, 74 'J',0, A_FF_LINE, 75 'K',0, A_BF_LINE, 76 'Y',0, A_BF_LINE, 77 'd',0, A_F_SCROLL, 78 CONTROL('D'),0, A_F_SCROLL, 79 'u',0, A_B_SCROLL, 80 CONTROL('U'),0, A_B_SCROLL, 81 ' ',0, A_F_SCREEN, 82 'f',0, A_F_SCREEN, 83 CONTROL('F'),0, A_F_SCREEN, 84 CONTROL('V'),0, A_F_SCREEN, 85 'b',0, A_B_SCREEN, 86 CONTROL('B'),0, A_B_SCREEN, 87 ESC,'v',0, A_B_SCREEN, 88 'z',0, A_F_WINDOW, 89 'w',0, A_B_WINDOW, 90 'F',0, A_F_FOREVER, 91 'R',0, A_FREPAINT, 92 'r',0, A_REPAINT, 93 CONTROL('R'),0, A_REPAINT, 94 CONTROL('L'),0, A_REPAINT, 95 ESC,'u',0, A_UNDO_SEARCH, 96 'g',0, A_GOLINE, 97 '<',0, A_GOLINE, 98 ESC,'<',0, A_GOLINE, 99 'p',0, A_PERCENT, 100 '%',0, A_PERCENT, 101 '{',0, A_F_BRACKET|A_EXTRA, '{','}',0, 102 '}',0, A_B_BRACKET|A_EXTRA, '{','}',0, 103 '(',0, A_F_BRACKET|A_EXTRA, '(',')',0, 104 ')',0, A_B_BRACKET|A_EXTRA, '(',')',0, 105 '[',0, A_F_BRACKET|A_EXTRA, '[',']',0, 106 ']',0, A_B_BRACKET|A_EXTRA, '[',']',0, 107 ESC,CONTROL('F'),0, A_F_BRACKET, 108 ESC,CONTROL('B'),0, A_B_BRACKET, 109 'G',0, A_GOEND, 110 ESC,'>',0, A_GOEND, 111 '>',0, A_GOEND, 112 'P',0, A_GOPOS, 113 114 '0',0, A_DIGIT, 115 '1',0, A_DIGIT, 116 '2',0, A_DIGIT, 117 '3',0, A_DIGIT, 118 '4',0, A_DIGIT, 119 '5',0, A_DIGIT, 120 '6',0, A_DIGIT, 121 '7',0, A_DIGIT, 122 '8',0, A_DIGIT, 123 '9',0, A_DIGIT, 124 125 '=',0, A_STAT, 126 CONTROL('G'),0, A_STAT, 127 ':','f',0, A_STAT, 128 '/',0, A_F_SEARCH, 129 '?',0, A_B_SEARCH, 130 ESC,'/',0, A_F_SEARCH|A_EXTRA, '*',0, 131 ESC,'?',0, A_B_SEARCH|A_EXTRA, '*',0, 132 'n',0, A_AGAIN_SEARCH, 133 ESC,'n',0, A_T_AGAIN_SEARCH, 134 'N',0, A_REVERSE_SEARCH, 135 ESC,'N',0, A_T_REVERSE_SEARCH, 136 'm',0, A_SETMARK, 137 '\'',0, A_GOMARK, 138 CONTROL('X'),CONTROL('X'),0, A_GOMARK, 139 'E',0, A_EXAMINE, 140 ':','e',0, A_EXAMINE, 141 CONTROL('X'),CONTROL('V'),0, A_EXAMINE, 142 ':','n',0, A_NEXT_FILE, 143 ':','p',0, A_PREV_FILE, 144 ':','x',0, A_INDEX_FILE, 145 '-',0, A_OPT_TOGGLE, 146 ':','t',0, A_OPT_TOGGLE|A_EXTRA, 't',0, 147 's',0, A_OPT_TOGGLE|A_EXTRA, 'o',0, 148 '_',0, A_DISP_OPTION, 149 '|',0, A_PIPE, 150 'v',0, A_VISUAL, 151 '!',0, A_SHELL, 152 '+',0, A_FIRSTCMD, 153 154 'H',0, A_HELP, 155 'h',0, A_HELP, 156 'V',0, A_VERSION, 157 'q',0, A_QUIT, 158 ':','q',0, A_QUIT, 159 ':','Q',0, A_QUIT, 160 'Z','Z',0, A_QUIT 161 }; 162 163 static unsigned char edittable[] = 164 { 165 '\t',0, EC_F_COMPLETE, /* TAB */ 166 '\17',0, EC_B_COMPLETE, /* BACKTAB */ 167 '\14',0, EC_EXPAND, /* CTRL-L */ 168 CONTROL('V'),0, EC_LITERAL, /* BACKSLASH */ 169 CONTROL('A'),0, EC_LITERAL, /* BACKSLASH */ 170 ESC,'l',0, EC_RIGHT, /* ESC l */ 171 ESC,'h',0, EC_LEFT, /* ESC h */ 172 ESC,'b',0, EC_W_LEFT, /* ESC b */ 173 ESC,'w',0, EC_W_RIGHT, /* ESC w */ 174 ESC,'i',0, EC_INSERT, /* ESC i */ 175 ESC,'x',0, EC_DELETE, /* ESC x */ 176 ESC,'X',0, EC_W_DELETE, /* ESC X */ 177 ESC,'\b',0, EC_W_BACKSPACE, /* ESC BACKSPACE */ 178 ESC,'0',0, EC_HOME, /* ESC 0 */ 179 ESC,'$',0, EC_END, /* ESC $ */ 180 ESC,'k',0, EC_UP, /* ESC k */ 181 ESC,'j',0, EC_DOWN, /* ESC j */ 182 ESC,'\t',0, EC_B_COMPLETE /* ESC TAB */ 183 }; 184 185 /* 186 * Structure to support a list of command tables. 187 */ 188 struct tablelist 189 { 190 struct tablelist *t_next; 191 char *t_start; 192 char *t_end; 193 }; 194 195 /* 196 * List of command tables and list of line-edit tables. 197 */ 198 static struct tablelist *list_fcmd_tables = NULL; 199 static struct tablelist *list_ecmd_tables = NULL; 200 201 202 /* 203 * Initialize the command lists. 204 */ 205 public void 206 init_cmds() 207 { 208 /* 209 * Add the default command tables. 210 */ 211 add_fcmd_table((char*)cmdtable, sizeof(cmdtable)); 212 add_ecmd_table((char*)edittable, sizeof(edittable)); 213 get_editkeys(); 214 #if USERFILE 215 /* 216 * Try to add the tables in the standard lesskey file "$HOME/.less". 217 */ 218 add_hometable(); 219 #endif 220 } 221 222 /* 223 * 224 */ 225 static int 226 add_cmd_table(tlist, buf, len) 227 struct tablelist **tlist; 228 char *buf; 229 int len; 230 { 231 struct tablelist *t; 232 233 if (len == 0) 234 return (0); 235 /* 236 * Allocate a tablelist structure, initialize it, 237 * and link it into the list of tables. 238 */ 239 if ((t = (struct tablelist *) 240 calloc(1, sizeof(struct tablelist))) == NULL) 241 { 242 return (-1); 243 } 244 t->t_start = buf; 245 t->t_end = buf + len; 246 t->t_next = *tlist; 247 *tlist = t; 248 return (0); 249 } 250 251 /* 252 * Add a command table. 253 */ 254 public void 255 add_fcmd_table(buf, len) 256 char *buf; 257 int len; 258 { 259 if (add_cmd_table(&list_fcmd_tables, buf, len) < 0) 260 error("Warning: some commands disabled", NULL_PARG); 261 } 262 263 /* 264 * Add an editing command table. 265 */ 266 public void 267 add_ecmd_table(buf, len) 268 char *buf; 269 int len; 270 { 271 if (add_cmd_table(&list_ecmd_tables, buf, len) < 0) 272 error("Warning: some edit commands disabled", NULL_PARG); 273 } 274 275 /* 276 * Search a single command table for the command string in cmd. 277 */ 278 public int 279 cmd_search(cmd, table, endtable, sp) 280 char *cmd; 281 char *table; 282 char *endtable; 283 char **sp; 284 { 285 char *p; 286 char *q; 287 int a; 288 289 for (p = table, q = cmd; p < endtable; p++, q++) 290 { 291 if (*p == *q) 292 { 293 /* 294 * Current characters match. 295 * If we're at the end of the string, we've found it. 296 * Return the action code, which is the character 297 * after the null at the end of the string 298 * in the command table. 299 */ 300 if (*p == '\0') 301 { 302 a = *++p & 0377; 303 if (a == A_END_LIST) 304 { 305 /* 306 * We get here only if the original 307 * cmd string passed in was empty (""). 308 * I don't think that can happen, 309 * but just in case ... 310 */ 311 return (A_UINVALID); 312 } 313 /* 314 * Check for an "extra" string. 315 */ 316 if (a & A_EXTRA) 317 { 318 *sp = ++p; 319 a &= ~A_EXTRA; 320 } else 321 *sp = NULL; 322 return (a); 323 } 324 } else if (*q == '\0') 325 { 326 /* 327 * Hit the end of the user's command, 328 * but not the end of the string in the command table. 329 * The user's command is incomplete. 330 */ 331 return (A_PREFIX); 332 } else 333 { 334 /* 335 * Not a match. 336 * Skip ahead to the next command in the 337 * command table, and reset the pointer 338 * to the beginning of the user's command. 339 */ 340 if (*p == '\0' && p[1] == A_END_LIST) 341 { 342 /* 343 * A_END_LIST is a special marker that tells 344 * us to abort the cmd search. 345 */ 346 return (A_UINVALID); 347 } 348 while (*p++ != '\0') ; 349 if (*p & A_EXTRA) 350 while (*++p != '\0') ; 351 q = cmd-1; 352 } 353 } 354 /* 355 * No match found in the entire command table. 356 */ 357 return (A_INVALID); 358 } 359 360 /* 361 * Decode a command character and return the associated action. 362 * The "extra" string, if any, is returned in sp. 363 */ 364 static int 365 cmd_decode(tlist, cmd, sp) 366 struct tablelist *tlist; 367 char *cmd; 368 char **sp; 369 { 370 struct tablelist *t; 371 int action = A_INVALID; 372 373 /* 374 * Search thru all the command tables. 375 * Stop when we find an action which is not A_INVALID. 376 */ 377 for (t = tlist; t != NULL; t = t->t_next) 378 { 379 action = cmd_search(cmd, t->t_start, t->t_end, sp); 380 if (action != A_INVALID) 381 break; 382 } 383 return (action); 384 } 385 386 /* 387 * Decode a command from the cmdtables list. 388 */ 389 public int 390 fcmd_decode(cmd, sp) 391 char *cmd; 392 char **sp; 393 { 394 return (cmd_decode(list_fcmd_tables, cmd, sp)); 395 } 396 397 /* 398 * Decode a command from the edittables list. 399 */ 400 public int 401 ecmd_decode(cmd, sp) 402 char *cmd; 403 char **sp; 404 { 405 return (cmd_decode(list_ecmd_tables, cmd, sp)); 406 } 407 408 #if USERFILE 409 static int 410 gint(sp) 411 char **sp; 412 { 413 int n; 414 415 n = *(*sp)++; 416 n += *(*sp)++ * KRADIX; 417 return (n); 418 } 419 420 static int 421 old_lesskey(buf, len) 422 char *buf; 423 int len; 424 { 425 /* 426 * Old-style lesskey file. 427 * The file must end with either 428 * ...,cmd,0,action 429 * or ...,cmd,0,action|A_EXTRA,string,0 430 * So the last byte or the second to last byte must be zero. 431 */ 432 if (buf[len-1] != '\0' && buf[len-2] != '\0') 433 return (-1); 434 add_fcmd_table(buf, len); 435 return (0); 436 } 437 438 static int 439 new_lesskey(buf, len) 440 char *buf; 441 int len; 442 { 443 char *p; 444 int c; 445 int done; 446 int n; 447 448 /* 449 * New-style lesskey file. 450 * Extract the pieces. 451 */ 452 if (buf[len-3] != C0_END_LESSKEY_MAGIC || 453 buf[len-2] != C1_END_LESSKEY_MAGIC || 454 buf[len-1] != C2_END_LESSKEY_MAGIC) 455 return (-1); 456 p = buf + 4; 457 done = 0; 458 while (!done) 459 { 460 c = *p++; 461 switch (c) 462 { 463 case CMD_SECTION: 464 n = gint(&p); 465 add_fcmd_table(p, n); 466 p += n; 467 break; 468 case EDIT_SECTION: 469 n = gint(&p); 470 add_ecmd_table(p, n); 471 p += n; 472 break; 473 case END_SECTION: 474 done = 1; 475 break; 476 default: 477 free(buf); 478 return (-1); 479 } 480 } 481 return (0); 482 } 483 484 /* 485 * Set up a user command table, based on a "lesskey" file. 486 */ 487 public int 488 lesskey(filename) 489 char *filename; 490 { 491 char *buf; 492 POSITION len; 493 long n; 494 int f; 495 496 /* 497 * Try to open the lesskey file. 498 */ 499 f = open(filename, OPEN_READ); 500 if (f < 0) 501 return (1); 502 503 /* 504 * Read the file into a buffer. 505 * We first figure out the size of the file and allocate space for it. 506 * {{ Minimal error checking is done here. 507 * A garbage .less file will produce strange results. 508 * To avoid a large amount of error checking code here, we 509 * rely on the lesskey program to generate a good .less file. }} 510 */ 511 len = filesize(f); 512 if (len == NULL_POSITION || len < 3) 513 { 514 /* 515 * Bad file (valid file must have at least 3 chars). 516 */ 517 close(f); 518 return (-1); 519 } 520 if ((buf = (char *) calloc((int)len, sizeof(char))) == NULL) 521 { 522 close(f); 523 return (-1); 524 } 525 if (lseek(f, (off_t)0, 0) == BAD_LSEEK) 526 { 527 free(buf); 528 close(f); 529 return (-1); 530 } 531 n = read(f, buf, (unsigned int) len); 532 close(f); 533 if (n != len) 534 { 535 free(buf); 536 return (-1); 537 } 538 539 /* 540 * Figure out if this is an old-style (before version 241) 541 * or new-style lesskey file format. 542 */ 543 if (buf[0] != C0_LESSKEY_MAGIC || buf[1] != C1_LESSKEY_MAGIC || 544 buf[2] != C2_LESSKEY_MAGIC || buf[3] != C3_LESSKEY_MAGIC) 545 return (old_lesskey(buf, (int)len)); 546 return (new_lesskey(buf, (int)len)); 547 } 548 549 /* 550 * Add the standard lesskey file "$HOME/.less" 551 */ 552 public void 553 add_hometable() 554 { 555 char *filename; 556 PARG parg; 557 558 filename = homefile(LESSKEYFILE); 559 if (filename == NULL) 560 return; 561 if (lesskey(filename) < 0) 562 { 563 parg.p_string = filename; 564 error("Cannot use lesskey file \"%s\"", &parg); 565 } 566 free(filename); 567 } 568 #endif 569 570 /* 571 * See if a char is a special line-editing command. 572 */ 573 public int 574 editchar(c, flags) 575 int c; 576 int flags; 577 { 578 int action; 579 int nch; 580 char *s; 581 char usercmd[MAX_CMDLEN+1]; 582 583 /* 584 * An editing character could actually be a sequence of characters; 585 * for example, an escape sequence sent by pressing the uparrow key. 586 * To match the editing string, we use the command decoder 587 * but give it the edit-commands command table 588 * This table is constructed to match the user's keyboard. 589 */ 590 if (c == erase_char) 591 return (EC_BACKSPACE); 592 if (c == kill_char) 593 return (EC_LINEKILL); 594 595 /* 596 * Collect characters in a buffer. 597 * Start with the one we have, and get more if we need them. 598 */ 599 nch = 0; 600 do { 601 if (nch > 0) 602 c = getcc(); 603 usercmd[nch] = c; 604 usercmd[nch+1] = '\0'; 605 nch++; 606 action = ecmd_decode(usercmd, &s); 607 } while (action == A_PREFIX); 608 609 if (flags & EC_NOHISTORY) 610 { 611 /* 612 * The caller says there is no history list. 613 * Reject any history-manipulation action. 614 */ 615 switch (action) 616 { 617 case EC_UP: 618 case EC_DOWN: 619 action = A_INVALID; 620 break; 621 } 622 } 623 if (flags & EC_NOCOMPLETE) 624 { 625 /* 626 * The caller says we don't want any filename completion cmds. 627 * Reject them. 628 */ 629 switch (action) 630 { 631 case EC_F_COMPLETE: 632 case EC_B_COMPLETE: 633 case EC_EXPAND: 634 action = A_INVALID; 635 break; 636 } 637 } 638 if ((flags & EC_PEEK) || action == A_INVALID) 639 { 640 /* 641 * We're just peeking, or we didn't understand the command. 642 * Unget all the characters we read in the loop above. 643 * This does NOT include the original character that was 644 * passed in as a parameter. 645 */ 646 while (nch > 1) { 647 ungetcc(usercmd[--nch]); 648 } 649 } else 650 { 651 if (s != NULL) 652 ungetsc(s); 653 } 654 return action; 655 } 656 657