1 /*- 2 * Copyright (c) 1992 Diomidis Spinellis. 3 * Copyright (c) 1992, 1993 4 * The Regents of the University of California. All rights reserved. 5 * 6 * This code is derived from software contributed to Berkeley by 7 * Diomidis Spinellis of Imperial College, University of London. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. All advertising materials mentioning features or use of this software 18 * must display the following acknowledgement: 19 * This product includes software developed by the University of 20 * California, Berkeley and its contributors. 21 * 4. Neither the name of the University nor the names of its contributors 22 * may be used to endorse or promote products derived from this software 23 * without specific prior written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35 * SUCH DAMAGE. 36 */ 37 38 #ifndef lint 39 /* from: static char sccsid[] = "@(#)compile.c 8.1 (Berkeley) 6/6/93"; */ 40 static char *rcsid = "$Id: compile.c,v 1.11 1994/04/17 04:19:27 alm Exp $"; 41 #endif /* not lint */ 42 43 #include <sys/types.h> 44 #include <sys/stat.h> 45 46 #include <ctype.h> 47 #include <errno.h> 48 #include <fcntl.h> 49 #include <limits.h> 50 #include <regex.h> 51 #include <stdio.h> 52 #include <stdlib.h> 53 #include <string.h> 54 55 #include "defs.h" 56 #include "extern.h" 57 58 #define LHSZ 128 59 #define LHMASK (LHSZ - 1) 60 static struct labhash { 61 struct labhash *lh_next; 62 u_int lh_hash; 63 struct s_command *lh_cmd; 64 int lh_ref; 65 } *labels[LHSZ]; 66 67 static char *compile_addr __P((char *, struct s_addr *)); 68 static char *compile_ccl __P((char **, char *)); 69 static char *compile_delimited __P((char *, char *)); 70 static char *compile_flags __P((char *, struct s_subst *)); 71 static char *compile_re __P((char *, regex_t **)); 72 static char *compile_subst __P((char *, struct s_subst *)); 73 static char *compile_text __P((void)); 74 static char *compile_tr __P((char *, char **)); 75 static struct s_command 76 **compile_stream __P((char *, struct s_command **, char *)); 77 static char *duptoeol __P((char *, char *)); 78 static void enterlabel __P((struct s_command *)); 79 static struct s_command 80 *findlabel __P((char *)); 81 static void fixuplabel __P((struct s_command *, struct s_command *)); 82 static void uselabel __P((void)); 83 84 /* 85 * Command specification. This is used to drive the command parser. 86 */ 87 struct s_format { 88 char code; /* Command code */ 89 int naddr; /* Number of address args */ 90 enum e_args args; /* Argument type */ 91 }; 92 93 static struct s_format cmd_fmts[] = { 94 {'{', 2, GROUP}, 95 {'a', 1, TEXT}, 96 {'b', 2, BRANCH}, 97 {'c', 2, TEXT}, 98 {'d', 2, EMPTY}, 99 {'D', 2, EMPTY}, 100 {'g', 2, EMPTY}, 101 {'G', 2, EMPTY}, 102 {'h', 2, EMPTY}, 103 {'H', 2, EMPTY}, 104 {'i', 1, TEXT}, 105 {'l', 2, EMPTY}, 106 {'n', 2, EMPTY}, 107 {'N', 2, EMPTY}, 108 {'p', 2, EMPTY}, 109 {'P', 2, EMPTY}, 110 {'q', 1, EMPTY}, 111 {'r', 1, RFILE}, 112 {'s', 2, SUBST}, 113 {'t', 2, BRANCH}, 114 {'w', 2, WFILE}, 115 {'x', 2, EMPTY}, 116 {'y', 2, TR}, 117 {'!', 2, NONSEL}, 118 {':', 0, LABEL}, 119 {'#', 0, COMMENT}, 120 {'=', 1, EMPTY}, 121 {'\0', 0, COMMENT}, 122 }; 123 124 /* The compiled program. */ 125 struct s_command *prog; 126 127 /* 128 * Compile the program into prog. 129 * Initialise appends. 130 */ 131 void 132 compile() 133 { 134 *compile_stream(NULL, &prog, NULL) = NULL; 135 fixuplabel(prog, NULL); 136 uselabel(); 137 appends = xmalloc(sizeof(struct s_appends) * appendnum); 138 match = xmalloc((maxnsub + 1) * sizeof(regmatch_t)); 139 } 140 141 #define EATSPACE() do { \ 142 if (p) \ 143 while (*p && isascii(*p) && isspace(*p)) \ 144 p++; \ 145 } while (0) 146 147 static struct s_command ** 148 compile_stream(terminator, link, p) 149 char *terminator; 150 struct s_command **link; 151 register char *p; 152 { 153 static char lbuf[_POSIX2_LINE_MAX + 1]; /* To save stack */ 154 struct s_command *cmd, *cmd2; 155 struct s_format *fp; 156 int naddr; /* Number of addresses */ 157 158 if (p != NULL) 159 goto semicolon; 160 for (;;) { 161 if ((p = cu_fgets(lbuf, sizeof(lbuf))) == NULL) { 162 if (terminator != NULL) 163 err(COMPILE, "unexpected EOF (pending }'s)"); 164 return (link); 165 } 166 167 semicolon: EATSPACE(); 168 if (p && (*p == '#' || *p == '\0')) 169 continue; 170 if (*p == '}') { 171 if (terminator == NULL) 172 err(COMPILE, "unexpected }"); 173 return (link); 174 } 175 *link = cmd = xmalloc(sizeof(struct s_command)); 176 link = &cmd->next; 177 cmd->nonsel = cmd->inrange = 0; 178 /* First parse the addresses */ 179 naddr = 0; 180 cmd->a1 = cmd->a2 = NULL; 181 182 /* Valid characters to start an address */ 183 #define addrchar(c) (strchr("0123456789/\\$", (c))) 184 if (addrchar(*p)) { 185 naddr++; 186 cmd->a1 = xmalloc(sizeof(struct s_addr)); 187 p = compile_addr(p, cmd->a1); 188 EATSPACE(); /* EXTENSION */ 189 if (*p == ',') { 190 naddr++; 191 p++; 192 EATSPACE(); /* EXTENSION */ 193 cmd->a2 = xmalloc(sizeof(struct s_addr)); 194 p = compile_addr(p, cmd->a2); 195 } 196 } 197 198 nonsel: /* Now parse the command */ 199 EATSPACE(); 200 if (!*p) 201 err(COMPILE, "command expected"); 202 cmd->code = *p; 203 for (fp = cmd_fmts; fp->code; fp++) 204 if (fp->code == *p) 205 break; 206 if (!fp->code) 207 err(COMPILE, "invalid command code %c", *p); 208 if (naddr > fp->naddr) 209 err(COMPILE, 210 "command %c expects up to %d address(es), found %d", *p, fp->naddr, naddr); 211 switch (fp->args) { 212 case NONSEL: /* ! */ 213 cmd->nonsel = ! cmd->nonsel; 214 p++; 215 goto nonsel; 216 case GROUP: /* { */ 217 p++; 218 EATSPACE(); 219 if (!*p) 220 p = NULL; 221 cmd2 = xmalloc(sizeof(struct s_command)); 222 cmd2->code = '}'; 223 *compile_stream("}", &cmd->u.c, p) = cmd2; 224 cmd->next = cmd2; 225 link = &cmd2->next; 226 break; 227 case EMPTY: /* d D g G h H l n N p P q x = \0 */ 228 p++; 229 EATSPACE(); 230 if (*p == ';') { 231 p++; 232 link = &cmd->next; 233 goto semicolon; 234 } 235 if (*p) 236 err(COMPILE, 237 "extra characters at the end of %c command", cmd->code); 238 break; 239 case TEXT: /* a c i */ 240 p++; 241 EATSPACE(); 242 if (*p != '\\') 243 err(COMPILE, 244 "command %c expects \\ followed by text", cmd->code); 245 p++; 246 EATSPACE(); 247 if (*p) 248 err(COMPILE, 249 "extra characters after \\ at the end of %c command", cmd->code); 250 cmd->t = compile_text(); 251 break; 252 case COMMENT: /* \0 # */ 253 break; 254 case WFILE: /* w */ 255 p++; 256 EATSPACE(); 257 if (*p == '\0') 258 err(COMPILE, "filename expected"); 259 cmd->t = duptoeol(p, "w command"); 260 if (aflag) 261 cmd->u.fd = -1; 262 else if ((cmd->u.fd = open(p, 263 O_WRONLY|O_APPEND|O_CREAT|O_TRUNC, 264 DEFFILEMODE)) == -1) 265 err(FATAL, "%s: %s\n", p, strerror(errno)); 266 break; 267 case RFILE: /* r */ 268 p++; 269 EATSPACE(); 270 if (*p == '\0') 271 err(COMPILE, "filename expected"); 272 else 273 cmd->t = duptoeol(p, "read command"); 274 break; 275 case BRANCH: /* b t */ 276 p++; 277 EATSPACE(); 278 if (*p == '\0') 279 cmd->t = NULL; 280 else 281 cmd->t = duptoeol(p, "branch"); 282 break; 283 case LABEL: /* : */ 284 p++; 285 EATSPACE(); 286 cmd->t = duptoeol(p, "label"); 287 if (strlen(p) == 0) 288 err(COMPILE, "empty label"); 289 enterlabel(cmd); 290 break; 291 case SUBST: /* s */ 292 p++; 293 if (*p == '\0' || *p == '\\') 294 err(COMPILE, 295 "substitute pattern can not be delimited by newline or backslash"); 296 cmd->u.s = xmalloc(sizeof(struct s_subst)); 297 p = compile_re(p, &cmd->u.s->re); 298 if (p == NULL) 299 err(COMPILE, "unterminated substitute pattern"); 300 --p; 301 p = compile_subst(p, cmd->u.s); 302 p = compile_flags(p, cmd->u.s); 303 EATSPACE(); 304 if (*p == ';') { 305 p++; 306 link = &cmd->next; 307 goto semicolon; 308 } 309 break; 310 case TR: /* y */ 311 p++; 312 p = compile_tr(p, (char **)&cmd->u.y); 313 EATSPACE(); 314 if (*p == ';') { 315 p++; 316 link = &cmd->next; 317 goto semicolon; 318 } 319 if (*p) 320 err(COMPILE, 321 "extra text at the end of a transform command"); 322 break; 323 } 324 } 325 } 326 327 /* 328 * Get a delimited string. P points to the delimeter of the string; d points 329 * to a buffer area. Newline and delimiter escapes are processed; other 330 * escapes are ignored. 331 * 332 * Returns a pointer to the first character after the final delimiter or NULL 333 * in the case of a non-terminated string. The character array d is filled 334 * with the processed string. 335 */ 336 static char * 337 compile_delimited(p, d) 338 char *p, *d; 339 { 340 char c; 341 342 c = *p++; 343 if (c == '\0') 344 return (NULL); 345 else if (c == '\\') 346 err(COMPILE, "\\ can not be used as a string delimiter"); 347 else if (c == '\n') 348 err(COMPILE, "newline can not be used as a string delimiter"); 349 while (*p) { 350 if (*p == '[') { 351 if ((d = compile_ccl(&p, d)) == NULL) 352 err(COMPILE, "unbalanced brackets ([])"); 353 continue; 354 } else if (*p == '\\' && p[1] == '[') { 355 *d++ = *p++; 356 } else if (*p == '\\' && p[1] == c) 357 p++; 358 else if (*p == '\\' && p[1] == 'n') { 359 *d++ = '\n'; 360 p += 2; 361 continue; 362 } else if (*p == '\\' && p[1] == '\\') 363 *d++ = *p++; 364 else if (*p == c) { 365 *d = '\0'; 366 return (p + 1); 367 } 368 *d++ = *p++; 369 } 370 return (NULL); 371 } 372 373 374 /* compile_ccl: expand a POSIX character class */ 375 static char * 376 compile_ccl(sp, t) 377 char **sp; 378 char *t; 379 { 380 int c, d; 381 char *s = *sp; 382 383 *t++ = *s++; 384 if (*s == '^') 385 *t++ = *s++; 386 if (*s == ']') 387 *t++ = *s++; 388 for (; *s && (*t = *s) != ']'; s++, t++) 389 if (*s == '[' && ((d = *(s+1)) == '.' || d == ':' || d == '=')) { 390 *++t = *++s, t++, s++; 391 for (c = *s; (*t = *s) != ']' || c != d; s++, t++) 392 if ((c = *s) == '\0') 393 return NULL; 394 } else if (*s == '\\' && s[1] == 'n') 395 *t = '\n', s++; 396 return (*s == ']') ? *sp = ++s, ++t : NULL; 397 } 398 399 /* 400 * Get a regular expression. P points to the delimiter of the regular 401 * expression; repp points to the address of a regexp pointer. Newline 402 * and delimiter escapes are processed; other escapes are ignored. 403 * Returns a pointer to the first character after the final delimiter 404 * or NULL in the case of a non terminated regular expression. The regexp 405 * pointer is set to the compiled regular expression. 406 * Cflags are passed to regcomp. 407 */ 408 static char * 409 compile_re(p, repp) 410 char *p; 411 regex_t **repp; 412 { 413 int eval; 414 char re[_POSIX2_LINE_MAX + 1]; 415 416 p = compile_delimited(p, re); 417 if (p && strlen(re) == 0) { 418 *repp = NULL; 419 return (p); 420 } 421 *repp = xmalloc(sizeof(regex_t)); 422 if (p && (eval = regcomp(*repp, re, 0)) != 0) 423 err(COMPILE, "RE error: %s", strregerror(eval, *repp)); 424 if (maxnsub < (*repp)->re_nsub) 425 maxnsub = (*repp)->re_nsub; 426 return (p); 427 } 428 429 /* 430 * Compile the substitution string of a regular expression and set res to 431 * point to a saved copy of it. Nsub is the number of parenthesized regular 432 * expressions. 433 */ 434 static char * 435 compile_subst(p, s) 436 char *p; 437 struct s_subst *s; 438 { 439 static char lbuf[_POSIX2_LINE_MAX + 1]; 440 int asize, ref, size; 441 char c, *text, *op, *sp; 442 443 c = *p++; /* Terminator character */ 444 if (c == '\0') 445 return (NULL); 446 447 s->maxbref = 0; 448 s->linenum = linenum; 449 asize = 2 * _POSIX2_LINE_MAX + 1; 450 text = xmalloc(asize); 451 size = 0; 452 do { 453 op = sp = text + size; 454 for (; *p; p++) { 455 if (*p == '\\') { 456 p++; 457 if (strchr("123456789", *p) != NULL) { 458 *sp++ = '\\'; 459 ref = *p - '0'; 460 if (s->re != NULL && 461 ref > s->re->re_nsub) 462 err(COMPILE, 463 "\\%c not defined in the RE", *p); 464 if (s->maxbref < ref) 465 s->maxbref = ref; 466 } else if (*p == '&' || *p == '\\') 467 *sp++ = '\\'; 468 } else if (*p == c) { 469 p++; 470 *sp++ = '\0'; 471 size += sp - op; 472 s->new = xrealloc(text, size); 473 return (p); 474 } else if (*p == '\n') { 475 err(COMPILE, 476 "unescaped newline inside substitute pattern"); 477 /* NOTREACHED */ 478 } 479 *sp++ = *p; 480 } 481 size += sp - op; 482 if (asize - size < _POSIX2_LINE_MAX + 1) { 483 asize *= 2; 484 text = xmalloc(asize); 485 } 486 } while (cu_fgets(p = lbuf, sizeof(lbuf))); 487 err(COMPILE, "unterminated substitute in regular expression"); 488 /* NOTREACHED */ 489 } 490 491 /* 492 * Compile the flags of the s command 493 */ 494 static char * 495 compile_flags(p, s) 496 char *p; 497 struct s_subst *s; 498 { 499 int gn; /* True if we have seen g or n */ 500 char wfile[_POSIX2_LINE_MAX + 1], *q; 501 502 s->n = 1; /* Default */ 503 s->p = 0; 504 s->wfile = NULL; 505 s->wfd = -1; 506 for (gn = 0;;) { 507 EATSPACE(); /* EXTENSION */ 508 switch (*p) { 509 case 'g': 510 if (gn) 511 err(COMPILE, 512 "more than one number or 'g' in substitute flags"); 513 gn = 1; 514 s->n = 0; 515 break; 516 case '\0': 517 case '\n': 518 case ';': 519 return (p); 520 case 'p': 521 s->p = 1; 522 break; 523 case '1': case '2': case '3': 524 case '4': case '5': case '6': 525 case '7': case '8': case '9': 526 if (gn) 527 err(COMPILE, 528 "more than one number or 'g' in substitute flags"); 529 gn = 1; 530 /* XXX Check for overflow */ 531 s->n = (int)strtol(p, &p, 10); 532 break; 533 case 'w': 534 p++; 535 #ifdef HISTORIC_PRACTICE 536 if (*p != ' ') { 537 err(WARNING, "space missing before w wfile"); 538 return (p); 539 } 540 #endif 541 EATSPACE(); 542 q = wfile; 543 while (*p) { 544 if (*p == '\n') 545 break; 546 *q++ = *p++; 547 } 548 *q = '\0'; 549 if (q == wfile) 550 err(COMPILE, "no wfile specified"); 551 s->wfile = strdup(wfile); 552 if (!aflag && (s->wfd = open(wfile, 553 O_WRONLY|O_APPEND|O_CREAT|O_TRUNC, 554 DEFFILEMODE)) == -1) 555 err(FATAL, "%s: %s\n", wfile, strerror(errno)); 556 return (p); 557 default: 558 err(COMPILE, 559 "bad flag in substitute command: '%c'", *p); 560 break; 561 } 562 p++; 563 } 564 } 565 566 /* 567 * Compile a translation set of strings into a lookup table. 568 */ 569 static char * 570 compile_tr(p, transtab) 571 char *p; 572 char **transtab; 573 { 574 int i; 575 char *lt, *op, *np; 576 char old[_POSIX2_LINE_MAX + 1]; 577 char new[_POSIX2_LINE_MAX + 1]; 578 579 if (*p == '\0' || *p == '\\') 580 err(COMPILE, 581 "transform pattern can not be delimited by newline or backslash"); 582 p = compile_delimited(p, old); 583 if (p == NULL) { 584 err(COMPILE, "unterminated transform source string"); 585 return (NULL); 586 } 587 p = compile_delimited(--p, new); 588 if (p == NULL) { 589 err(COMPILE, "unterminated transform target string"); 590 return (NULL); 591 } 592 EATSPACE(); 593 if (strlen(new) != strlen(old)) { 594 err(COMPILE, "transform strings are not the same length"); 595 return (NULL); 596 } 597 /* We assume characters are 8 bits */ 598 lt = xmalloc(UCHAR_MAX); 599 for (i = 0; i <= UCHAR_MAX; i++) 600 lt[i] = (char)i; 601 for (op = old, np = new; *op; op++, np++) 602 lt[(u_char)*op] = *np; 603 *transtab = lt; 604 return (p); 605 } 606 607 /* 608 * Compile the text following an a or i command. 609 */ 610 static char * 611 compile_text() 612 { 613 int asize, size; 614 char *text, *p, *op, *s; 615 char lbuf[_POSIX2_LINE_MAX + 1]; 616 617 asize = 2 * _POSIX2_LINE_MAX + 1; 618 text = xmalloc(asize); 619 size = 0; 620 while (cu_fgets(lbuf, sizeof(lbuf))) { 621 op = s = text + size; 622 p = lbuf; 623 EATSPACE(); 624 for (; *p; p++) { 625 if (*p == '\\') 626 p++; 627 *s++ = *p; 628 } 629 size += s - op; 630 if (p[-2] != '\\') { 631 *s = '\0'; 632 break; 633 } 634 if (asize - size < _POSIX2_LINE_MAX + 1) { 635 asize *= 2; 636 text = xmalloc(asize); 637 } 638 } 639 return (xrealloc(text, size + 1)); 640 } 641 642 /* 643 * Get an address and return a pointer to the first character after 644 * it. Fill the structure pointed to according to the address. 645 */ 646 static char * 647 compile_addr(p, a) 648 char *p; 649 struct s_addr *a; 650 { 651 char *end; 652 653 switch (*p) { 654 case '\\': /* Context address */ 655 ++p; 656 /* FALLTHROUGH */ 657 case '/': /* Context address */ 658 p = compile_re(p, &a->u.r); 659 if (p == NULL) 660 err(COMPILE, "unterminated regular expression"); 661 a->type = AT_RE; 662 return (p); 663 664 case '$': /* Last line */ 665 a->type = AT_LAST; 666 return (p + 1); 667 /* Line number */ 668 case '0': case '1': case '2': case '3': case '4': 669 case '5': case '6': case '7': case '8': case '9': 670 a->type = AT_LINE; 671 a->u.l = strtol(p, &end, 10); 672 return (end); 673 default: 674 err(COMPILE, "expected context address"); 675 return (NULL); 676 } 677 } 678 679 /* 680 * duptoeol -- 681 * Return a copy of all the characters up to \n or \0. 682 */ 683 static char * 684 duptoeol(s, ctype) 685 register char *s; 686 char *ctype; 687 { 688 size_t len; 689 int ws; 690 char *start; 691 692 ws = 0; 693 for (start = s; *s != '\0' && *s != '\n'; ++s) 694 ws = isspace(*s); 695 *s = '\0'; 696 if (ws) 697 err(WARNING, "whitespace after %s", ctype); 698 len = s - start + 1; 699 return (memmove(xmalloc(len), start, len)); 700 } 701 702 /* 703 * Convert goto label names to addresses, and count a and r commands, in 704 * the given subset of the script. Free the memory used by labels in b 705 * and t commands (but not by :). 706 * 707 * TODO: Remove } nodes 708 */ 709 static void 710 fixuplabel(cp, end) 711 struct s_command *cp, *end; 712 { 713 714 for (; cp != end; cp = cp->next) 715 switch (cp->code) { 716 case 'a': 717 case 'r': 718 appendnum++; 719 break; 720 case 'b': 721 case 't': 722 /* Resolve branch target. */ 723 if (cp->t == NULL) { 724 cp->u.c = NULL; 725 break; 726 } 727 if ((cp->u.c = findlabel(cp->t)) == NULL) 728 err(COMPILE2, "undefined label '%s'", cp->t); 729 free(cp->t); 730 break; 731 case '{': 732 /* Do interior commands. */ 733 fixuplabel(cp->u.c, cp->next); 734 break; 735 } 736 } 737 738 /* 739 * Associate the given command label for later lookup. 740 */ 741 static void 742 enterlabel(cp) 743 struct s_command *cp; 744 { 745 register struct labhash **lhp, *lh; 746 register u_char *p; 747 register u_int h, c; 748 749 for (h = 0, p = (u_char *)cp->t; (c = *p) != 0; p++) 750 h = (h << 5) + h + c; 751 lhp = &labels[h & LHMASK]; 752 for (lh = *lhp; lh != NULL; lh = lh->lh_next) 753 if (lh->lh_hash == h && strcmp(cp->t, lh->lh_cmd->t) == 0) 754 err(COMPILE2, "duplicate label '%s'", cp->t); 755 lh = xmalloc(sizeof *lh); 756 lh->lh_next = *lhp; 757 lh->lh_hash = h; 758 lh->lh_cmd = cp; 759 lh->lh_ref = 0; 760 *lhp = lh; 761 } 762 763 /* 764 * Find the label contained in the command l in the command linked 765 * list cp. L is excluded from the search. Return NULL if not found. 766 */ 767 static struct s_command * 768 findlabel(name) 769 char *name; 770 { 771 register struct labhash *lh; 772 register u_char *p; 773 register u_int h, c; 774 775 for (h = 0, p = (u_char *)name; (c = *p) != 0; p++) 776 h = (h << 5) + h + c; 777 for (lh = labels[h & LHMASK]; lh != NULL; lh = lh->lh_next) { 778 if (lh->lh_hash == h && strcmp(name, lh->lh_cmd->t) == 0) { 779 lh->lh_ref = 1; 780 return (lh->lh_cmd); 781 } 782 } 783 return (NULL); 784 } 785 786 /* 787 * Warn about any unused labels. As a side effect, release the label hash 788 * table space. 789 */ 790 static void 791 uselabel() 792 { 793 register struct labhash *lh, *next; 794 register int i; 795 796 for (i = 0; i < LHSZ; i++) { 797 for (lh = labels[i]; lh != NULL; lh = next) { 798 next = lh->lh_next; 799 if (!lh->lh_ref) 800 err(WARNING, "unused label '%s'", 801 lh->lh_cmd->t); 802 free(lh); 803 } 804 } 805 } 806