1 /* $OpenBSD: compile.c,v 1.34 2010/11/15 20:26:00 millert 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 #include <sys/types.h> 37 #include <sys/stat.h> 38 39 #include <ctype.h> 40 #include <errno.h> 41 #include <fcntl.h> 42 #include <limits.h> 43 #include <regex.h> 44 #include <stdio.h> 45 #include <stdlib.h> 46 #include <string.h> 47 48 #include "defs.h" 49 #include "extern.h" 50 51 #define LHSZ 128 52 #define LHMASK (LHSZ - 1) 53 static struct labhash { 54 struct labhash *lh_next; 55 u_int lh_hash; 56 struct s_command *lh_cmd; 57 int lh_ref; 58 } *labels[LHSZ]; 59 60 static char *compile_addr(char *, struct s_addr *); 61 static char *compile_ccl(char **, char *); 62 static char *compile_delimited(char *, char *, int); 63 static char *compile_flags(char *, struct s_subst *); 64 static char *compile_re(char *, regex_t **); 65 static char *compile_subst(char *, struct s_subst *); 66 static char *compile_text(void); 67 static char *compile_tr(char *, char **); 68 static struct s_command 69 **compile_stream(struct s_command **); 70 static char *duptoeol(char *, char *, char **); 71 static void enterlabel(struct s_command *); 72 static struct s_command 73 *findlabel(char *); 74 static void fixuplabel(struct s_command *, struct s_command *); 75 static void uselabel(void); 76 77 /* 78 * Command specification. This is used to drive the command parser. 79 */ 80 struct s_format { 81 char code; /* Command code */ 82 int naddr; /* Number of address args */ 83 enum e_args args; /* Argument type */ 84 }; 85 86 static struct s_format cmd_fmts[] = { 87 {'{', 2, GROUP}, 88 {'}', 0, ENDGROUP}, 89 {'a', 1, TEXT}, 90 {'b', 2, BRANCH}, 91 {'c', 2, TEXT}, 92 {'d', 2, EMPTY}, 93 {'D', 2, EMPTY}, 94 {'g', 2, EMPTY}, 95 {'G', 2, EMPTY}, 96 {'h', 2, EMPTY}, 97 {'H', 2, EMPTY}, 98 {'i', 1, TEXT}, 99 {'l', 2, EMPTY}, 100 {'n', 2, EMPTY}, 101 {'N', 2, EMPTY}, 102 {'p', 2, EMPTY}, 103 {'P', 2, EMPTY}, 104 {'q', 1, EMPTY}, 105 {'r', 1, RFILE}, 106 {'s', 2, SUBST}, 107 {'t', 2, BRANCH}, 108 {'w', 2, WFILE}, 109 {'x', 2, EMPTY}, 110 {'y', 2, TR}, 111 {'!', 2, NONSEL}, 112 {':', 0, LABEL}, 113 {'#', 0, COMMENT}, 114 {'=', 1, EMPTY}, 115 {'\0', 0, COMMENT}, 116 }; 117 118 /* The compiled program. */ 119 struct s_command *prog; 120 121 /* 122 * Compile the program into prog. 123 * Initialise appends. 124 */ 125 void 126 compile(void) 127 { 128 *compile_stream(&prog) = NULL; 129 fixuplabel(prog, NULL); 130 uselabel(); 131 appends = xmalloc(sizeof(struct s_appends) * appendnum); 132 match = xmalloc((maxnsub + 1) * sizeof(regmatch_t)); 133 } 134 135 #define EATSPACE() do { \ 136 if (p) \ 137 while (isascii(*p) && isspace(*p)) \ 138 p++; \ 139 } while (0) 140 141 static struct s_command ** 142 compile_stream(struct s_command **link) 143 { 144 char *p; 145 static char *lbuf; /* To avoid excessive malloc calls */ 146 static size_t bufsize; 147 struct s_command *cmd, *cmd2, *stack; 148 struct s_format *fp; 149 int naddr; /* Number of addresses */ 150 151 stack = 0; 152 for (;;) { 153 if ((p = cu_fgets(&lbuf, &bufsize)) == NULL) { 154 if (stack != 0) 155 err(COMPILE, "unexpected EOF (pending }'s)"); 156 return (link); 157 } 158 159 semicolon: EATSPACE(); 160 if (*p == '#' || *p == '\0') 161 continue; 162 if (*p == ';') { 163 p++; 164 goto semicolon; 165 } 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 } 189 } else { 190 cmd->a1 = cmd->a2 = 0; 191 } 192 193 nonsel: /* Now parse the command */ 194 if (!*p) 195 err(COMPILE, "command expected"); 196 cmd->code = *p; 197 for (fp = cmd_fmts; fp->code; fp++) 198 if (fp->code == *p) 199 break; 200 if (!fp->code) 201 err(COMPILE, "invalid command code %c", *p); 202 if (naddr > fp->naddr) 203 err(COMPILE, 204 "command %c expects up to %d address(es), found %d", 205 *p, fp->naddr, naddr); 206 switch (fp->args) { 207 case NONSEL: /* ! */ 208 p++; 209 EATSPACE(); 210 cmd->nonsel = ! cmd->nonsel; 211 goto nonsel; 212 case GROUP: /* { */ 213 p++; 214 EATSPACE(); 215 cmd->next = stack; 216 stack = cmd; 217 link = &cmd->u.c; 218 if (*p) 219 goto semicolon; 220 break; 221 case ENDGROUP: 222 /* 223 * Short-circuit command processing, since end of 224 * group is really just a noop. 225 */ 226 cmd->nonsel = 1; 227 if (stack == 0) 228 err(COMPILE, "unexpected }"); 229 cmd2 = stack; 230 stack = cmd2->next; 231 cmd2->next = cmd; 232 /*FALLTHROUGH*/ 233 case EMPTY: /* d D g G h H l n N p P q x = \0 */ 234 p++; 235 EATSPACE(); 236 if (*p == ';') { 237 p++; 238 link = &cmd->next; 239 goto semicolon; 240 } 241 if (*p) 242 err(COMPILE, 243 "extra characters at the end of %c command", cmd->code); 244 break; 245 case TEXT: /* a c i */ 246 p++; 247 EATSPACE(); 248 if (*p != '\\') 249 err(COMPILE, "command %c expects \\ followed by" 250 " text", cmd->code); 251 p++; 252 EATSPACE(); 253 if (*p) 254 err(COMPILE, "extra characters after \\ at the" 255 " end of %c command", cmd->code); 256 cmd->t = compile_text(); 257 break; 258 case COMMENT: /* \0 # */ 259 break; 260 case WFILE: /* w */ 261 p++; 262 EATSPACE(); 263 if (*p == '\0') 264 err(COMPILE, "filename expected"); 265 cmd->t = duptoeol(p, "w command", NULL); 266 if (aflag) 267 cmd->u.fd = -1; 268 else if ((cmd->u.fd = open(p, 269 O_WRONLY|O_APPEND|O_CREAT|O_TRUNC, 270 DEFFILEMODE)) == -1) 271 err(FATAL, "%s: %s", p, strerror(errno)); 272 break; 273 case RFILE: /* r */ 274 p++; 275 EATSPACE(); 276 cmd->t = duptoeol(p, "read command", NULL); 277 break; 278 case BRANCH: /* b t */ 279 p++; 280 EATSPACE(); 281 if (*p == '\0') 282 cmd->t = NULL; 283 else 284 cmd->t = duptoeol(p, "branch", &p); 285 if (*p == ';') { 286 p++; 287 goto semicolon; 288 } 289 break; 290 case LABEL: /* : */ 291 p++; 292 EATSPACE(); 293 cmd->t = duptoeol(p, "label", &p); 294 if (strlen(cmd->t) == 0) 295 err(COMPILE, "empty label"); 296 enterlabel(cmd); 297 if (*p == ';') { 298 p++; 299 goto semicolon; 300 } 301 break; 302 case SUBST: /* s */ 303 p++; 304 if (*p == '\0' || *p == '\\') 305 err(COMPILE, "substitute pattern can not be" 306 " delimited by newline or backslash"); 307 cmd->u.s = xmalloc(sizeof(struct s_subst)); 308 p = compile_re(p, &cmd->u.s->re); 309 if (p == NULL) 310 err(COMPILE, "unterminated substitute pattern"); 311 --p; 312 p = compile_subst(p, cmd->u.s); 313 p = compile_flags(p, cmd->u.s); 314 EATSPACE(); 315 if (*p == ';') { 316 p++; 317 link = &cmd->next; 318 goto semicolon; 319 } 320 break; 321 case TR: /* y */ 322 p++; 323 p = compile_tr(p, (char **)&cmd->u.y); 324 EATSPACE(); 325 if (*p == ';') { 326 p++; 327 link = &cmd->next; 328 goto semicolon; 329 } 330 if (*p) 331 err(COMPILE, "extra text at the end of a" 332 " transform command"); 333 break; 334 } 335 } 336 } 337 338 /* 339 * Get a delimited string. P points to the delimeter of the string; d points 340 * to a buffer area. Newline and delimiter escapes are processed; other 341 * escapes are ignored. 342 * 343 * Returns a pointer to the first character after the final delimiter or NULL 344 * in the case of a non-terminated string. The character array d is filled 345 * with the processed string. 346 */ 347 static char * 348 compile_delimited(char *p, char *d, int is_tr) 349 { 350 char c; 351 352 c = *p++; 353 if (c == '\0') 354 return (NULL); 355 else if (c == '\\') 356 err(COMPILE, "\\ can not be used as a string delimiter"); 357 else if (c == '\n') 358 err(COMPILE, "newline can not be used as a string delimiter"); 359 while (*p) { 360 if (*p == '[' && *p != c) { 361 if ((d = compile_ccl(&p, d)) == NULL) 362 err(COMPILE, "unbalanced brackets ([])"); 363 continue; 364 } else if (*p == '\\' && p[1] == '[') { 365 *d++ = *p++; 366 } else if (*p == '\\' && p[1] == c) { 367 p++; 368 } else if (*p == '\\' && p[1] == 'n') { 369 *d++ = '\n'; 370 p += 2; 371 continue; 372 } else if (*p == '\\' && p[1] == '\\') { 373 if (is_tr) 374 p++; 375 else 376 *d++ = *p++; 377 } else if (*p == c) { 378 *d = '\0'; 379 return (p + 1); 380 } 381 *d++ = *p++; 382 } 383 return (NULL); 384 } 385 386 387 /* compile_ccl: expand a POSIX character class */ 388 static char * 389 compile_ccl(char **sp, char *t) 390 { 391 int c, d; 392 char *s = *sp; 393 394 *t++ = *s++; 395 if (*s == '^') 396 *t++ = *s++; 397 if (*s == ']') 398 *t++ = *s++; 399 for (; *s && (*t = *s) != ']'; s++, t++) 400 if (*s == '[' && ((d = *(s+1)) == '.' || d == ':' || d == '=')) { 401 *++t = *++s, t++, s++; 402 for (c = *s; (*t = *s) != ']' || c != d; s++, t++) 403 if ((c = *s) == '\0') 404 return NULL; 405 } else if (*s == '\\' && s[1] == 'n') { 406 *t = '\n'; 407 s++; 408 } 409 if (*s == ']') { 410 *sp = ++s; 411 return (++t); 412 } else { 413 return (NULL); 414 } 415 } 416 417 /* 418 * Get a regular expression. P points to the delimiter of the regular 419 * expression; repp points to the address of a regexp pointer. Newline 420 * and delimiter escapes are processed; other escapes are ignored. 421 * Returns a pointer to the first character after the final delimiter 422 * or NULL in the case of a non terminated regular expression. The regexp 423 * pointer is set to the compiled regular expression. 424 * Cflags are passed to regcomp. 425 */ 426 static char * 427 compile_re(char *p, regex_t **repp) 428 { 429 int eval; 430 char *re; 431 432 re = xmalloc(strlen(p) + 1); /* strlen(re) <= strlen(p) */ 433 p = compile_delimited(p, re, 0); 434 if (p && strlen(re) == 0) { 435 *repp = NULL; 436 free(re); 437 return (p); 438 } 439 *repp = xmalloc(sizeof(regex_t)); 440 if (p && (eval = regcomp(*repp, re, Eflag ? REG_EXTENDED : 0)) != 0) 441 err(COMPILE, "RE error: %s", strregerror(eval, *repp)); 442 if (maxnsub < (*repp)->re_nsub) 443 maxnsub = (*repp)->re_nsub; 444 free(re); 445 return (p); 446 } 447 448 /* 449 * Compile the substitution string of a regular expression and set res to 450 * point to a saved copy of it. Nsub is the number of parenthesized regular 451 * expressions. 452 */ 453 static char * 454 compile_subst(char *p, struct s_subst *s) 455 { 456 static char *lbuf; 457 static size_t bufsize; 458 int asize, ref, size; 459 char c, *text, *op, *sp; 460 int sawesc = 0; 461 462 c = *p++; /* Terminator character */ 463 if (c == '\0') 464 return (NULL); 465 466 s->maxbref = 0; 467 s->linenum = linenum; 468 text = NULL; 469 asize = size = 0; 470 do { 471 size_t len = ROUNDLEN(strlen(p) + 1); 472 if (asize - size < len) { 473 do { 474 asize += len; 475 } while (asize - size < len); 476 text = xrealloc(text, asize); 477 } 478 op = sp = text + size; 479 for (; *p; p++) { 480 if (*p == '\\' || sawesc) { 481 /* 482 * If this is a continuation from the last 483 * buffer, we won't have a character to 484 * skip over. 485 */ 486 if (sawesc) 487 sawesc = 0; 488 else 489 p++; 490 491 if (*p == '\0') { 492 /* 493 * This escaped character is continued 494 * in the next part of the line. Note 495 * this fact, then cause the loop to 496 * exit w/ normal EOL case and reenter 497 * above with the new buffer. 498 */ 499 sawesc = 1; 500 p--; 501 continue; 502 } else if (strchr("123456789", *p) != NULL) { 503 *sp++ = '\\'; 504 ref = *p - '0'; 505 if (s->re != NULL && 506 ref > s->re->re_nsub) 507 err(COMPILE, 508 "\\%c not defined in the RE", *p); 509 if (s->maxbref < ref) 510 s->maxbref = ref; 511 } else if (*p == '&' || *p == '\\') 512 *sp++ = '\\'; 513 } else if (*p == c) { 514 p++; 515 *sp++ = '\0'; 516 size += sp - op; 517 s->new = xrealloc(text, size); 518 return (p); 519 } else if (*p == '\n') { 520 err(COMPILE, 521 "unescaped newline inside substitute pattern"); 522 /* NOTREACHED */ 523 } 524 *sp++ = *p; 525 } 526 size += sp - op; 527 } while ((p = cu_fgets(&lbuf, &bufsize))); 528 err(COMPILE, "unterminated substitute in regular expression"); 529 /* NOTREACHED */ 530 } 531 532 /* 533 * Compile the flags of the s command 534 */ 535 static char * 536 compile_flags(char *p, struct s_subst *s) 537 { 538 int gn; /* True if we have seen g or n */ 539 long l; 540 char wfile[PATH_MAX], *q; 541 542 s->n = 1; /* Default */ 543 s->p = 0; 544 s->wfile = NULL; 545 s->wfd = -1; 546 for (gn = 0;;) { 547 EATSPACE(); /* EXTENSION */ 548 switch (*p) { 549 case 'g': 550 if (gn) 551 err(COMPILE, "more than one number or 'g' in" 552 " substitute flags"); 553 gn = 1; 554 s->n = 0; 555 break; 556 case '\0': 557 case '\n': 558 case ';': 559 return (p); 560 case 'p': 561 s->p = 1; 562 break; 563 case '1': case '2': case '3': 564 case '4': case '5': case '6': 565 case '7': case '8': case '9': 566 if (gn) 567 err(COMPILE, "more than one number or 'g' in" 568 " substitute flags"); 569 gn = 1; 570 l = strtol(p, &p, 10); 571 if (l <= 0 || l >= INT_MAX) 572 err(COMPILE, 573 "number in substitute flags out of range"); 574 s->n = (int)l; 575 continue; 576 case 'w': 577 p++; 578 #ifdef HISTORIC_PRACTICE 579 if (*p != ' ') { 580 err(WARNING, "space missing before w wfile"); 581 return (p); 582 } 583 #endif 584 EATSPACE(); 585 q = wfile; 586 while (*p) { 587 if (*p == '\n') 588 break; 589 *q++ = *p++; 590 } 591 *q = '\0'; 592 if (q == wfile) 593 err(COMPILE, "no wfile specified"); 594 s->wfile = strdup(wfile); 595 if (!aflag && (s->wfd = open(wfile, 596 O_WRONLY|O_APPEND|O_CREAT|O_TRUNC, 597 DEFFILEMODE)) == -1) 598 err(FATAL, "%s: %s", wfile, strerror(errno)); 599 return (p); 600 default: 601 err(COMPILE, 602 "bad flag in substitute command: '%c'", *p); 603 break; 604 } 605 p++; 606 } 607 } 608 609 /* 610 * Compile a translation set of strings into a lookup table. 611 */ 612 static char * 613 compile_tr(char *p, char **transtab) 614 { 615 int i; 616 char *lt, *op, *np; 617 char *old = NULL, *new = NULL; 618 619 if (*p == '\0' || *p == '\\') 620 err(COMPILE, 621 "transform pattern can not be delimited by newline or backslash"); 622 old = xmalloc(strlen(p) + 1); 623 p = compile_delimited(p, old, 1); 624 if (p == NULL) { 625 err(COMPILE, "unterminated transform source string"); 626 goto bad; 627 } 628 new = xmalloc(strlen(p) + 1); 629 p = compile_delimited(--p, new, 1); 630 if (p == NULL) { 631 err(COMPILE, "unterminated transform target string"); 632 goto bad; 633 } 634 EATSPACE(); 635 if (strlen(new) != strlen(old)) { 636 err(COMPILE, "transform strings are not the same length"); 637 goto bad; 638 } 639 /* We assume characters are 8 bits */ 640 lt = xmalloc(UCHAR_MAX + 1); 641 for (i = 0; i <= UCHAR_MAX; i++) 642 lt[i] = (char)i; 643 for (op = old, np = new; *op; op++, np++) 644 lt[(u_char)*op] = *np; 645 *transtab = lt; 646 free(old); 647 free(new); 648 return (p); 649 bad: 650 free(old); 651 free(new); 652 return (NULL); 653 } 654 655 /* 656 * Compile the text following an a, c, or i command. 657 */ 658 static char * 659 compile_text(void) 660 { 661 int asize, esc_nl, size; 662 char *lbuf, *text, *p, *op, *s; 663 size_t bufsize; 664 665 lbuf = text = NULL; 666 asize = size = 0; 667 while ((p = cu_fgets(&lbuf, &bufsize))) { 668 size_t len = ROUNDLEN(strlen(p) + 1); 669 if (asize - size < len) { 670 do { 671 asize += len; 672 } while (asize - size < len); 673 text = xrealloc(text, asize); 674 } 675 op = s = text + size; 676 for (esc_nl = 0; *p != '\0'; p++) { 677 if (*p == '\\' && p[1] != '\0' && *++p == '\n') 678 esc_nl = 1; 679 *s++ = *p; 680 } 681 size += s - op; 682 if (!esc_nl) { 683 *s = '\0'; 684 break; 685 } 686 } 687 free(lbuf); 688 text = xrealloc(text, size + 1); 689 text[size] = '\0'; 690 return (text); 691 } 692 693 /* 694 * Get an address and return a pointer to the first character after 695 * it. Fill the structure pointed to according to the address. 696 */ 697 static char * 698 compile_addr(char *p, struct s_addr *a) 699 { 700 char *end; 701 702 switch (*p) { 703 case '\\': /* Context address */ 704 ++p; 705 /* FALLTHROUGH */ 706 case '/': /* Context address */ 707 p = compile_re(p, &a->u.r); 708 if (p == NULL) 709 err(COMPILE, "unterminated regular expression"); 710 a->type = AT_RE; 711 return (p); 712 713 case '$': /* Last line */ 714 a->type = AT_LAST; 715 return (p + 1); 716 /* Line number */ 717 case '0': case '1': case '2': case '3': case '4': 718 case '5': case '6': case '7': case '8': case '9': 719 a->type = AT_LINE; 720 a->u.l = strtoul(p, &end, 10); 721 return (end); 722 default: 723 err(COMPILE, "expected context address"); 724 return (NULL); 725 } 726 } 727 728 /* 729 * duptoeol -- 730 * Return a copy of all the characters up to \n or \0. 731 */ 732 static char * 733 duptoeol(char *s, char *ctype, char **semi) 734 { 735 size_t len; 736 int ws; 737 char *start; 738 739 ws = 0; 740 if (semi) { 741 for (start = s; *s != '\0' && *s != '\n' && *s != ';'; ++s) 742 ws = isspace(*s); 743 } else { 744 for (start = s; *s != '\0' && *s != '\n'; ++s) 745 ws = isspace(*s); 746 *s = '\0'; 747 } 748 if (ws) 749 err(WARNING, "whitespace after %s", ctype); 750 len = s - start + 1; 751 if (semi) 752 *semi = s; 753 s = xmalloc(len); 754 strlcpy(s, start, len); 755 return (s); 756 } 757 758 /* 759 * Convert goto label names to addresses, and count a and r commands, in 760 * the given subset of the script. Free the memory used by labels in b 761 * and t commands (but not by :). 762 * 763 * TODO: Remove } nodes 764 */ 765 static void 766 fixuplabel(struct s_command *cp, struct s_command *end) 767 { 768 769 for (; cp != end; cp = cp->next) 770 switch (cp->code) { 771 case 'a': 772 case 'r': 773 appendnum++; 774 break; 775 case 'b': 776 case 't': 777 /* Resolve branch target. */ 778 if (cp->t == NULL) { 779 cp->u.c = NULL; 780 break; 781 } 782 if ((cp->u.c = findlabel(cp->t)) == NULL) 783 err(COMPILE2, "undefined label '%s'", cp->t); 784 free(cp->t); 785 break; 786 case '{': 787 /* Do interior commands. */ 788 fixuplabel(cp->u.c, cp->next); 789 break; 790 } 791 } 792 793 /* 794 * Associate the given command label for later lookup. 795 */ 796 static void 797 enterlabel(struct s_command *cp) 798 { 799 struct labhash **lhp, *lh; 800 u_char *p; 801 u_int h, c; 802 803 for (h = 0, p = (u_char *)cp->t; (c = *p) != 0; p++) 804 h = (h << 5) + h + c; 805 lhp = &labels[h & LHMASK]; 806 for (lh = *lhp; lh != NULL; lh = lh->lh_next) 807 if (lh->lh_hash == h && strcmp(cp->t, lh->lh_cmd->t) == 0) 808 err(COMPILE2, "duplicate label '%s'", cp->t); 809 lh = xmalloc(sizeof *lh); 810 lh->lh_next = *lhp; 811 lh->lh_hash = h; 812 lh->lh_cmd = cp; 813 lh->lh_ref = 0; 814 *lhp = lh; 815 } 816 817 /* 818 * Find the label contained in the command l in the command linked 819 * list cp. L is excluded from the search. Return NULL if not found. 820 */ 821 static struct s_command * 822 findlabel(char *name) 823 { 824 struct labhash *lh; 825 u_char *p; 826 u_int h, c; 827 828 for (h = 0, p = (u_char *)name; (c = *p) != 0; p++) 829 h = (h << 5) + h + c; 830 for (lh = labels[h & LHMASK]; lh != NULL; lh = lh->lh_next) { 831 if (lh->lh_hash == h && strcmp(name, lh->lh_cmd->t) == 0) { 832 lh->lh_ref = 1; 833 return (lh->lh_cmd); 834 } 835 } 836 return (NULL); 837 } 838 839 /* 840 * Warn about any unused labels. As a side effect, release the label hash 841 * table space. 842 */ 843 static void 844 uselabel(void) 845 { 846 struct labhash *lh, *next; 847 int i; 848 849 for (i = 0; i < LHSZ; i++) { 850 for (lh = labels[i]; lh != NULL; lh = next) { 851 next = lh->lh_next; 852 if (!lh->lh_ref) 853 err(WARNING, "unused label '%s'", 854 lh->lh_cmd->t); 855 free(lh); 856 } 857 } 858 } 859