1 /* $OpenBSD: compile.c,v 1.15 2003/06/10 22:20:50 deraadt Exp $ */ 2 3 /*- 4 * Copyright (c) 1992 Diomidis Spinellis. 5 * Copyright (c) 1992, 1993 6 * The Regents of the University of California. All rights reserved. 7 * 8 * This code is derived from software contributed to Berkeley by 9 * Diomidis Spinellis of Imperial College, University of London. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36 #ifndef lint 37 /* from: static char sccsid[] = "@(#)compile.c 8.2 (Berkeley) 4/28/95"; */ 38 static char *rcsid = "$OpenBSD: compile.c,v 1.15 2003/06/10 22:20:50 deraadt Exp $"; 39 #endif /* not lint */ 40 41 #include <sys/types.h> 42 #include <sys/stat.h> 43 44 #include <ctype.h> 45 #include <errno.h> 46 #include <fcntl.h> 47 #include <limits.h> 48 #include <regex.h> 49 #include <stdio.h> 50 #include <stdlib.h> 51 #include <string.h> 52 53 #include "defs.h" 54 #include "extern.h" 55 56 #define LHSZ 128 57 #define LHMASK (LHSZ - 1) 58 static struct labhash { 59 struct labhash *lh_next; 60 u_int lh_hash; 61 struct s_command *lh_cmd; 62 int lh_ref; 63 } *labels[LHSZ]; 64 65 static char *compile_addr(char *, struct s_addr *); 66 static char *compile_ccl(char **, char *); 67 static char *compile_delimited(char *, char *); 68 static char *compile_flags(char *, struct s_subst *); 69 static char *compile_re(char *, regex_t **); 70 static char *compile_subst(char *, struct s_subst *); 71 static char *compile_text(void); 72 static char *compile_tr(char *, char **); 73 static struct s_command 74 **compile_stream(struct s_command **); 75 static char *duptoeol(char *, char *); 76 static void enterlabel(struct s_command *); 77 static struct s_command 78 *findlabel(char *); 79 static void fixuplabel(struct s_command *, struct s_command *); 80 static void uselabel(void); 81 82 /* 83 * Command specification. This is used to drive the command parser. 84 */ 85 struct s_format { 86 char code; /* Command code */ 87 int naddr; /* Number of address args */ 88 enum e_args args; /* Argument type */ 89 }; 90 91 static struct s_format cmd_fmts[] = { 92 {'{', 2, GROUP}, 93 {'}', 0, ENDGROUP}, 94 {'a', 1, TEXT}, 95 {'b', 2, BRANCH}, 96 {'c', 2, TEXT}, 97 {'d', 2, EMPTY}, 98 {'D', 2, EMPTY}, 99 {'g', 2, EMPTY}, 100 {'G', 2, EMPTY}, 101 {'h', 2, EMPTY}, 102 {'H', 2, EMPTY}, 103 {'i', 1, TEXT}, 104 {'l', 2, EMPTY}, 105 {'n', 2, EMPTY}, 106 {'N', 2, EMPTY}, 107 {'p', 2, EMPTY}, 108 {'P', 2, EMPTY}, 109 {'q', 1, EMPTY}, 110 {'r', 1, RFILE}, 111 {'s', 2, SUBST}, 112 {'t', 2, BRANCH}, 113 {'w', 2, WFILE}, 114 {'x', 2, EMPTY}, 115 {'y', 2, TR}, 116 {'!', 2, NONSEL}, 117 {':', 0, LABEL}, 118 {'#', 0, COMMENT}, 119 {'=', 1, EMPTY}, 120 {'\0', 0, COMMENT}, 121 }; 122 123 /* The compiled program. */ 124 struct s_command *prog; 125 126 /* 127 * Compile the program into prog. 128 * Initialise appends. 129 */ 130 void 131 compile(void) 132 { 133 *compile_stream(&prog) = NULL; 134 fixuplabel(prog, NULL); 135 uselabel(); 136 appends = xmalloc(sizeof(struct s_appends) * appendnum); 137 match = xmalloc((maxnsub + 1) * sizeof(regmatch_t)); 138 } 139 140 #define EATSPACE() do { \ 141 if (p) \ 142 while (*p && isascii(*p) && isspace(*p)) \ 143 p++; \ 144 } while (0) 145 146 static struct s_command ** 147 compile_stream(struct s_command **link) 148 { 149 char *p; 150 static char lbuf[_POSIX2_LINE_MAX + 1]; /* To save stack */ 151 struct s_command *cmd, *cmd2, *stack; 152 struct s_format *fp; 153 int naddr; /* Number of addresses */ 154 155 stack = 0; 156 for (;;) { 157 if ((p = cu_fgets(lbuf, sizeof(lbuf))) == NULL) { 158 if (stack != 0) 159 err(COMPILE, "unexpected EOF (pending }'s)"); 160 return (link); 161 } 162 163 semicolon: EATSPACE(); 164 if (p && (*p == '#' || *p == '\0')) 165 continue; 166 *link = cmd = xmalloc(sizeof(struct s_command)); 167 link = &cmd->next; 168 cmd->nonsel = cmd->inrange = 0; 169 /* First parse the addresses */ 170 naddr = 0; 171 172 /* Valid characters to start an address */ 173 #define addrchar(c) (strchr("0123456789/\\$", (c))) 174 if (addrchar(*p)) { 175 naddr++; 176 cmd->a1 = xmalloc(sizeof(struct s_addr)); 177 p = compile_addr(p, cmd->a1); 178 EATSPACE(); /* EXTENSION */ 179 if (*p == ',') { 180 p++; 181 EATSPACE(); /* EXTENSION */ 182 naddr++; 183 cmd->a2 = xmalloc(sizeof(struct s_addr)); 184 p = compile_addr(p, cmd->a2); 185 EATSPACE(); 186 } else 187 cmd->a2 = 0; 188 } else 189 cmd->a1 = cmd->a2 = 0; 190 191 nonsel: /* Now parse the command */ 192 if (!*p) 193 err(COMPILE, "command expected"); 194 cmd->code = *p; 195 for (fp = cmd_fmts; fp->code; fp++) 196 if (fp->code == *p) 197 break; 198 if (!fp->code) 199 err(COMPILE, "invalid command code %c", *p); 200 if (naddr > fp->naddr) 201 err(COMPILE, 202 "command %c expects up to %d address(es), found %d", *p, fp->naddr, naddr); 203 switch (fp->args) { 204 case NONSEL: /* ! */ 205 p++; 206 EATSPACE(); 207 cmd->nonsel = ! cmd->nonsel; 208 goto nonsel; 209 case GROUP: /* { */ 210 p++; 211 EATSPACE(); 212 cmd->next = stack; 213 stack = cmd; 214 link = &cmd->u.c; 215 if (*p) 216 goto semicolon; 217 break; 218 case ENDGROUP: 219 /* 220 * Short-circuit command processing, since end of 221 * group is really just a noop. 222 */ 223 cmd->nonsel = 1; 224 if (stack == 0) 225 err(COMPILE, "unexpected }"); 226 cmd2 = stack; 227 stack = cmd2->next; 228 cmd2->next = cmd; 229 /*FALLTHROUGH*/ 230 case EMPTY: /* d D g G h H l n N p P q x = \0 */ 231 p++; 232 EATSPACE(); 233 if (*p == ';') { 234 p++; 235 link = &cmd->next; 236 goto semicolon; 237 } 238 if (*p) 239 err(COMPILE, 240 "extra characters at the end of %c command", cmd->code); 241 break; 242 case TEXT: /* a c i */ 243 p++; 244 EATSPACE(); 245 if (*p != '\\') 246 err(COMPILE, 247 "command %c expects \\ followed by text", cmd->code); 248 p++; 249 EATSPACE(); 250 if (*p) 251 err(COMPILE, 252 "extra characters after \\ at the end of %c command", cmd->code); 253 cmd->t = compile_text(); 254 break; 255 case COMMENT: /* \0 # */ 256 break; 257 case WFILE: /* w */ 258 p++; 259 EATSPACE(); 260 if (*p == '\0') 261 err(COMPILE, "filename expected"); 262 cmd->t = duptoeol(p, "w command"); 263 if (aflag) 264 cmd->u.fd = -1; 265 else if ((cmd->u.fd = open(p, 266 O_WRONLY|O_APPEND|O_CREAT|O_TRUNC, 267 DEFFILEMODE)) == -1) 268 err(FATAL, "%s: %s", p, strerror(errno)); 269 break; 270 case RFILE: /* r */ 271 p++; 272 EATSPACE(); 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(char *p, char *d) 338 { 339 char c; 340 341 c = *p++; 342 if (c == '\0') 343 return (NULL); 344 else if (c == '\\') 345 err(COMPILE, "\\ can not be used as a string delimiter"); 346 else if (c == '\n') 347 err(COMPILE, "newline can not be used as a string delimiter"); 348 while (*p) { 349 if (*p == '[') { 350 if ((d = compile_ccl(&p, d)) == NULL) 351 err(COMPILE, "unbalanced brackets ([])"); 352 continue; 353 } else if (*p == '\\' && p[1] == '[') { 354 *d++ = *p++; 355 } else if (*p == '\\' && p[1] == c) 356 p++; 357 else if (*p == '\\' && p[1] == 'n') { 358 *d++ = '\n'; 359 p += 2; 360 continue; 361 } else if (*p == '\\' && p[1] == '\\') 362 *d++ = *p++; 363 else if (*p == c) { 364 *d = '\0'; 365 return (p + 1); 366 } 367 *d++ = *p++; 368 } 369 return (NULL); 370 } 371 372 373 /* compile_ccl: expand a POSIX character class */ 374 static char * 375 compile_ccl(char **sp, char *t) 376 { 377 int c, d; 378 char *s = *sp; 379 380 *t++ = *s++; 381 if (*s == '^') 382 *t++ = *s++; 383 if (*s == ']') 384 *t++ = *s++; 385 for (; *s && (*t = *s) != ']'; s++, t++) 386 if (*s == '[' && ((d = *(s+1)) == '.' || d == ':' || d == '=')) { 387 *++t = *++s, t++, s++; 388 for (c = *s; (*t = *s) != ']' || c != d; s++, t++) 389 if ((c = *s) == '\0') 390 return NULL; 391 } else if (*s == '\\' && s[1] == 'n') 392 *t = '\n', s++; 393 return (*s == ']') ? *sp = ++s, ++t : NULL; 394 } 395 396 /* 397 * Get a regular expression. P points to the delimiter of the regular 398 * expression; repp points to the address of a regexp pointer. Newline 399 * and delimiter escapes are processed; other escapes are ignored. 400 * Returns a pointer to the first character after the final delimiter 401 * or NULL in the case of a non terminated regular expression. The regexp 402 * pointer is set to the compiled regular expression. 403 * Cflags are passed to regcomp. 404 */ 405 static char * 406 compile_re(char *p, regex_t **repp) 407 { 408 int eval; 409 char re[_POSIX2_LINE_MAX + 1]; 410 411 p = compile_delimited(p, re); 412 if (p && strlen(re) == 0) { 413 *repp = NULL; 414 return (p); 415 } 416 *repp = xmalloc(sizeof(regex_t)); 417 if (p && (eval = regcomp(*repp, re, 0)) != 0) 418 err(COMPILE, "RE error: %s", strregerror(eval, *repp)); 419 if (maxnsub < (*repp)->re_nsub) 420 maxnsub = (*repp)->re_nsub; 421 return (p); 422 } 423 424 /* 425 * Compile the substitution string of a regular expression and set res to 426 * point to a saved copy of it. Nsub is the number of parenthesized regular 427 * expressions. 428 */ 429 static char * 430 compile_subst(char *p, struct s_subst *s) 431 { 432 static char lbuf[_POSIX2_LINE_MAX + 1]; 433 int asize, ref, size; 434 char c, *text, *op, *sp; 435 436 c = *p++; /* Terminator character */ 437 if (c == '\0') 438 return (NULL); 439 440 s->maxbref = 0; 441 s->linenum = linenum; 442 asize = 2 * _POSIX2_LINE_MAX + 1; 443 text = xmalloc(asize); 444 size = 0; 445 do { 446 op = sp = text + size; 447 for (; *p; p++) { 448 if (*p == '\\') { 449 p++; 450 if (strchr("123456789", *p) != NULL) { 451 *sp++ = '\\'; 452 ref = *p - '0'; 453 if (s->re != NULL && 454 ref > s->re->re_nsub) 455 err(COMPILE, 456 "\\%c not defined in the RE", *p); 457 if (s->maxbref < ref) 458 s->maxbref = ref; 459 } else if (*p == '&' || *p == '\\') 460 *sp++ = '\\'; 461 } else if (*p == c) { 462 p++; 463 *sp++ = '\0'; 464 size += sp - op; 465 s->new = xrealloc(text, size); 466 return (p); 467 } else if (*p == '\n') { 468 err(COMPILE, 469 "unescaped newline inside substitute pattern"); 470 /* NOTREACHED */ 471 } 472 *sp++ = *p; 473 } 474 size += sp - op; 475 if (asize - size < _POSIX2_LINE_MAX + 1) { 476 asize *= 2; 477 text = xmalloc(asize); 478 } 479 } while (cu_fgets(p = lbuf, sizeof(lbuf))); 480 err(COMPILE, "unterminated substitute in regular expression"); 481 /* NOTREACHED */ 482 } 483 484 /* 485 * Compile the flags of the s command 486 */ 487 static char * 488 compile_flags(char *p, struct s_subst *s) 489 { 490 int gn; /* True if we have seen g or n */ 491 char wfile[_POSIX2_LINE_MAX + 1], *q; 492 493 s->n = 1; /* Default */ 494 s->p = 0; 495 s->wfile = NULL; 496 s->wfd = -1; 497 for (gn = 0;;) { 498 EATSPACE(); /* EXTENSION */ 499 switch (*p) { 500 case 'g': 501 if (gn) 502 err(COMPILE, 503 "more than one number or 'g' in substitute flags"); 504 gn = 1; 505 s->n = 0; 506 break; 507 case '\0': 508 case '\n': 509 case ';': 510 return (p); 511 case 'p': 512 s->p = 1; 513 break; 514 case '1': case '2': case '3': 515 case '4': case '5': case '6': 516 case '7': case '8': case '9': 517 if (gn) 518 err(COMPILE, 519 "more than one number or 'g' in substitute flags"); 520 gn = 1; 521 /* XXX Check for overflow */ 522 s->n = (int)strtol(p, &p, 10); 523 break; 524 case 'w': 525 p++; 526 #ifdef HISTORIC_PRACTICE 527 if (*p != ' ') { 528 err(WARNING, "space missing before w wfile"); 529 return (p); 530 } 531 #endif 532 EATSPACE(); 533 q = wfile; 534 while (*p) { 535 if (*p == '\n') 536 break; 537 *q++ = *p++; 538 } 539 *q = '\0'; 540 if (q == wfile) 541 err(COMPILE, "no wfile specified"); 542 s->wfile = strdup(wfile); 543 if (!aflag && (s->wfd = open(wfile, 544 O_WRONLY|O_APPEND|O_CREAT|O_TRUNC, 545 DEFFILEMODE)) == -1) 546 err(FATAL, "%s: %s", wfile, strerror(errno)); 547 return (p); 548 default: 549 err(COMPILE, 550 "bad flag in substitute command: '%c'", *p); 551 break; 552 } 553 p++; 554 } 555 } 556 557 /* 558 * Compile a translation set of strings into a lookup table. 559 */ 560 static char * 561 compile_tr(char *p, char **transtab) 562 { 563 int i; 564 char *lt, *op, *np; 565 char old[_POSIX2_LINE_MAX + 1]; 566 char new[_POSIX2_LINE_MAX + 1]; 567 568 if (*p == '\0' || *p == '\\') 569 err(COMPILE, 570 "transform pattern can not be delimited by newline or backslash"); 571 p = compile_delimited(p, old); 572 if (p == NULL) { 573 err(COMPILE, "unterminated transform source string"); 574 return (NULL); 575 } 576 p = compile_delimited(--p, new); 577 if (p == NULL) { 578 err(COMPILE, "unterminated transform target string"); 579 return (NULL); 580 } 581 EATSPACE(); 582 if (strlen(new) != strlen(old)) { 583 err(COMPILE, "transform strings are not the same length"); 584 return (NULL); 585 } 586 /* We assume characters are 8 bits */ 587 lt = xmalloc(UCHAR_MAX); 588 for (i = 0; i <= UCHAR_MAX; i++) 589 lt[i] = (char)i; 590 for (op = old, np = new; *op; op++, np++) 591 lt[(u_char)*op] = *np; 592 *transtab = lt; 593 return (p); 594 } 595 596 /* 597 * Compile the text following an a, c, or i command. 598 */ 599 static char * 600 compile_text(void) 601 { 602 int asize, esc_nl, size; 603 char *text, *p, *op, *s; 604 char lbuf[_POSIX2_LINE_MAX + 1]; 605 606 asize = 2 * _POSIX2_LINE_MAX + 1; 607 text = xmalloc(asize); 608 size = 0; 609 while (cu_fgets(lbuf, sizeof(lbuf))) { 610 op = s = text + size; 611 p = lbuf; 612 EATSPACE(); 613 for (esc_nl = 0; *p != '\0'; p++) { 614 if (*p == '\\' && p[1] != '\0' && *++p == '\n') 615 esc_nl = 1; 616 *s++ = *p; 617 } 618 size += s - op; 619 if (!esc_nl) { 620 *s = '\0'; 621 break; 622 } 623 if (asize - size < _POSIX2_LINE_MAX + 1) { 624 asize *= 2; 625 text = xmalloc(asize); 626 } 627 } 628 text[size] = '\0'; 629 return (xrealloc(text, size + 1)); 630 } 631 632 /* 633 * Get an address and return a pointer to the first character after 634 * it. Fill the structure pointed to according to the address. 635 */ 636 static char * 637 compile_addr(char *p, struct s_addr *a) 638 { 639 char *end; 640 641 switch (*p) { 642 case '\\': /* Context address */ 643 ++p; 644 /* FALLTHROUGH */ 645 case '/': /* Context address */ 646 p = compile_re(p, &a->u.r); 647 if (p == NULL) 648 err(COMPILE, "unterminated regular expression"); 649 a->type = AT_RE; 650 return (p); 651 652 case '$': /* Last line */ 653 a->type = AT_LAST; 654 return (p + 1); 655 /* Line number */ 656 case '0': case '1': case '2': case '3': case '4': 657 case '5': case '6': case '7': case '8': case '9': 658 a->type = AT_LINE; 659 a->u.l = strtoul(p, &end, 10); 660 return (end); 661 default: 662 err(COMPILE, "expected context address"); 663 return (NULL); 664 } 665 } 666 667 /* 668 * duptoeol -- 669 * Return a copy of all the characters up to \n or \0. 670 */ 671 static char * 672 duptoeol(char *s, char *ctype) 673 { 674 size_t len; 675 int ws; 676 char *start; 677 678 ws = 0; 679 for (start = s; *s != '\0' && *s != '\n'; ++s) 680 ws = isspace(*s); 681 *s = '\0'; 682 if (ws) 683 err(WARNING, "whitespace after %s", ctype); 684 len = s - start + 1; 685 return (memmove(xmalloc(len), start, len)); 686 } 687 688 /* 689 * Convert goto label names to addresses, and count a and r commands, in 690 * the given subset of the script. Free the memory used by labels in b 691 * and t commands (but not by :). 692 * 693 * TODO: Remove } nodes 694 */ 695 static void 696 fixuplabel(struct s_command *cp, struct s_command *end) 697 { 698 699 for (; cp != end; cp = cp->next) 700 switch (cp->code) { 701 case 'a': 702 case 'r': 703 appendnum++; 704 break; 705 case 'b': 706 case 't': 707 /* Resolve branch target. */ 708 if (cp->t == NULL) { 709 cp->u.c = NULL; 710 break; 711 } 712 if ((cp->u.c = findlabel(cp->t)) == NULL) 713 err(COMPILE2, "undefined label '%s'", cp->t); 714 free(cp->t); 715 break; 716 case '{': 717 /* Do interior commands. */ 718 fixuplabel(cp->u.c, cp->next); 719 break; 720 } 721 } 722 723 /* 724 * Associate the given command label for later lookup. 725 */ 726 static void 727 enterlabel(struct s_command *cp) 728 { 729 struct labhash **lhp, *lh; 730 u_char *p; 731 u_int h, c; 732 733 for (h = 0, p = (u_char *)cp->t; (c = *p) != 0; p++) 734 h = (h << 5) + h + c; 735 lhp = &labels[h & LHMASK]; 736 for (lh = *lhp; lh != NULL; lh = lh->lh_next) 737 if (lh->lh_hash == h && strcmp(cp->t, lh->lh_cmd->t) == 0) 738 err(COMPILE2, "duplicate label '%s'", cp->t); 739 lh = xmalloc(sizeof *lh); 740 lh->lh_next = *lhp; 741 lh->lh_hash = h; 742 lh->lh_cmd = cp; 743 lh->lh_ref = 0; 744 *lhp = lh; 745 } 746 747 /* 748 * Find the label contained in the command l in the command linked 749 * list cp. L is excluded from the search. Return NULL if not found. 750 */ 751 static struct s_command * 752 findlabel(char *name) 753 { 754 struct labhash *lh; 755 u_char *p; 756 u_int h, c; 757 758 for (h = 0, p = (u_char *)name; (c = *p) != 0; p++) 759 h = (h << 5) + h + c; 760 for (lh = labels[h & LHMASK]; lh != NULL; lh = lh->lh_next) { 761 if (lh->lh_hash == h && strcmp(name, lh->lh_cmd->t) == 0) { 762 lh->lh_ref = 1; 763 return (lh->lh_cmd); 764 } 765 } 766 return (NULL); 767 } 768 769 /* 770 * Warn about any unused labels. As a side effect, release the label hash 771 * table space. 772 */ 773 static void 774 uselabel(void) 775 { 776 struct labhash *lh, *next; 777 int i; 778 779 for (i = 0; i < LHSZ; i++) { 780 for (lh = labels[i]; lh != NULL; lh = next) { 781 next = lh->lh_next; 782 if (!lh->lh_ref) 783 err(WARNING, "unused label '%s'", 784 lh->lh_cmd->t); 785 free(lh); 786 } 787 } 788 } 789