1 /* $OpenBSD: compile.c,v 1.24 2007/03/20 03:50:39 tedu 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 const char rcsid[] = "$OpenBSD: compile.c,v 1.24 2007/03/20 03:50:39 tedu 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 *, 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 (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 == '\0') 165 continue; 166 if (*p == ';') { 167 p++; 168 goto semicolon; 169 } 170 *link = cmd = xmalloc(sizeof(struct s_command)); 171 link = &cmd->next; 172 cmd->nonsel = cmd->inrange = 0; 173 /* First parse the addresses */ 174 naddr = 0; 175 176 /* Valid characters to start an address */ 177 #define addrchar(c) (strchr("0123456789/\\$", (c))) 178 if (addrchar(*p)) { 179 naddr++; 180 cmd->a1 = xmalloc(sizeof(struct s_addr)); 181 p = compile_addr(p, cmd->a1); 182 EATSPACE(); /* EXTENSION */ 183 if (*p == ',') { 184 p++; 185 EATSPACE(); /* EXTENSION */ 186 naddr++; 187 cmd->a2 = xmalloc(sizeof(struct s_addr)); 188 p = compile_addr(p, cmd->a2); 189 EATSPACE(); 190 } else { 191 cmd->a2 = 0; 192 } 193 } else { 194 cmd->a1 = cmd->a2 = 0; 195 } 196 197 nonsel: /* Now parse the command */ 198 if (!*p) 199 err(COMPILE, "command expected"); 200 cmd->code = *p; 201 for (fp = cmd_fmts; fp->code; fp++) 202 if (fp->code == *p) 203 break; 204 if (!fp->code) 205 err(COMPILE, "invalid command code %c", *p); 206 if (naddr > fp->naddr) 207 err(COMPILE, 208 "command %c expects up to %d address(es), found %d", 209 *p, fp->naddr, naddr); 210 switch (fp->args) { 211 case NONSEL: /* ! */ 212 p++; 213 EATSPACE(); 214 cmd->nonsel = ! cmd->nonsel; 215 goto nonsel; 216 case GROUP: /* { */ 217 p++; 218 EATSPACE(); 219 cmd->next = stack; 220 stack = cmd; 221 link = &cmd->u.c; 222 if (*p) 223 goto semicolon; 224 break; 225 case ENDGROUP: 226 /* 227 * Short-circuit command processing, since end of 228 * group is really just a noop. 229 */ 230 cmd->nonsel = 1; 231 if (stack == 0) 232 err(COMPILE, "unexpected }"); 233 cmd2 = stack; 234 stack = cmd2->next; 235 cmd2->next = cmd; 236 /*FALLTHROUGH*/ 237 case EMPTY: /* d D g G h H l n N p P q x = \0 */ 238 p++; 239 EATSPACE(); 240 if (*p == ';') { 241 p++; 242 link = &cmd->next; 243 goto semicolon; 244 } 245 if (*p) 246 err(COMPILE, 247 "extra characters at the end of %c command", cmd->code); 248 break; 249 case TEXT: /* a c i */ 250 p++; 251 EATSPACE(); 252 if (*p != '\\') 253 err(COMPILE, "command %c expects \\ followed by" 254 " text", cmd->code); 255 p++; 256 EATSPACE(); 257 if (*p) 258 err(COMPILE, "extra characters after \\ at the" 259 " end of %c command", cmd->code); 260 cmd->t = compile_text(); 261 break; 262 case COMMENT: /* \0 # */ 263 break; 264 case WFILE: /* w */ 265 p++; 266 EATSPACE(); 267 if (*p == '\0') 268 err(COMPILE, "filename expected"); 269 cmd->t = duptoeol(p, "w command", NULL); 270 if (aflag) 271 cmd->u.fd = -1; 272 else if ((cmd->u.fd = open(p, 273 O_WRONLY|O_APPEND|O_CREAT|O_TRUNC, 274 DEFFILEMODE)) == -1) 275 err(FATAL, "%s: %s", p, strerror(errno)); 276 break; 277 case RFILE: /* r */ 278 p++; 279 EATSPACE(); 280 cmd->t = duptoeol(p, "read command", NULL); 281 break; 282 case BRANCH: /* b t */ 283 p++; 284 EATSPACE(); 285 if (*p == '\0') 286 cmd->t = NULL; 287 else 288 cmd->t = duptoeol(p, "branch", &p); 289 if (*p == ';') { 290 p++; 291 goto semicolon; 292 } 293 break; 294 case LABEL: /* : */ 295 p++; 296 EATSPACE(); 297 cmd->t = duptoeol(p, "label", &p); 298 if (strlen(cmd->t) == 0) 299 err(COMPILE, "empty label"); 300 enterlabel(cmd); 301 if (*p == ';') { 302 p++; 303 goto semicolon; 304 } 305 break; 306 case SUBST: /* s */ 307 p++; 308 if (*p == '\0' || *p == '\\') 309 err(COMPILE, "substitute pattern can not be" 310 " delimited by newline or backslash"); 311 cmd->u.s = xmalloc(sizeof(struct s_subst)); 312 p = compile_re(p, &cmd->u.s->re); 313 if (p == NULL) 314 err(COMPILE, "unterminated substitute pattern"); 315 --p; 316 p = compile_subst(p, cmd->u.s); 317 p = compile_flags(p, cmd->u.s); 318 EATSPACE(); 319 if (*p == ';') { 320 p++; 321 link = &cmd->next; 322 goto semicolon; 323 } 324 break; 325 case TR: /* y */ 326 p++; 327 p = compile_tr(p, (char **)&cmd->u.y); 328 EATSPACE(); 329 if (*p == ';') { 330 p++; 331 link = &cmd->next; 332 goto semicolon; 333 } 334 if (*p) 335 err(COMPILE, "extra text at the end of a" 336 " transform command"); 337 break; 338 } 339 } 340 } 341 342 /* 343 * Get a delimited string. P points to the delimeter of the string; d points 344 * to a buffer area. Newline and delimiter escapes are processed; other 345 * escapes are ignored. 346 * 347 * Returns a pointer to the first character after the final delimiter or NULL 348 * in the case of a non-terminated string. The character array d is filled 349 * with the processed string. 350 */ 351 static char * 352 compile_delimited(char *p, char *d) 353 { 354 char c; 355 356 c = *p++; 357 if (c == '\0') 358 return (NULL); 359 else if (c == '\\') 360 err(COMPILE, "\\ can not be used as a string delimiter"); 361 else if (c == '\n') 362 err(COMPILE, "newline can not be used as a string delimiter"); 363 while (*p) { 364 if (*p == '[') { 365 if ((d = compile_ccl(&p, d)) == NULL) 366 err(COMPILE, "unbalanced brackets ([])"); 367 continue; 368 } else if (*p == '\\' && p[1] == '[') { 369 *d++ = *p++; 370 } else if (*p == '\\' && p[1] == c) { 371 p++; 372 } else if (*p == '\\' && p[1] == 'n') { 373 *d++ = '\n'; 374 p += 2; 375 continue; 376 } else if (*p == '\\' && p[1] == '\\') { 377 *d++ = *p++; 378 } else if (*p == c) { 379 *d = '\0'; 380 return (p + 1); 381 } 382 *d++ = *p++; 383 } 384 return (NULL); 385 } 386 387 388 /* compile_ccl: expand a POSIX character class */ 389 static char * 390 compile_ccl(char **sp, char *t) 391 { 392 int c, d; 393 char *s = *sp; 394 395 *t++ = *s++; 396 if (*s == '^') 397 *t++ = *s++; 398 if (*s == ']') 399 *t++ = *s++; 400 for (; *s && (*t = *s) != ']'; s++, t++) 401 if (*s == '[' && ((d = *(s+1)) == '.' || d == ':' || d == '=')) { 402 *++t = *++s, t++, s++; 403 for (c = *s; (*t = *s) != ']' || c != d; s++, t++) 404 if ((c = *s) == '\0') 405 return NULL; 406 } else if (*s == '\\' && s[1] == 'n') { 407 *t = '\n'; 408 s++; 409 } 410 if (*s == ']') { 411 *sp = ++s; 412 return (++t); 413 } else { 414 return (NULL); 415 } 416 } 417 418 /* 419 * Get a regular expression. P points to the delimiter of the regular 420 * expression; repp points to the address of a regexp pointer. Newline 421 * and delimiter escapes are processed; other escapes are ignored. 422 * Returns a pointer to the first character after the final delimiter 423 * or NULL in the case of a non terminated regular expression. The regexp 424 * pointer is set to the compiled regular expression. 425 * Cflags are passed to regcomp. 426 */ 427 static char * 428 compile_re(char *p, regex_t **repp) 429 { 430 int eval; 431 char re[_POSIX2_LINE_MAX + 1]; 432 433 p = compile_delimited(p, re); 434 if (p && strlen(re) == 0) { 435 *repp = NULL; 436 return (p); 437 } 438 *repp = xmalloc(sizeof(regex_t)); 439 if (p && (eval = regcomp(*repp, re, 0)) != 0) 440 err(COMPILE, "RE error: %s", strregerror(eval, *repp)); 441 if (maxnsub < (*repp)->re_nsub) 442 maxnsub = (*repp)->re_nsub; 443 return (p); 444 } 445 446 /* 447 * Compile the substitution string of a regular expression and set res to 448 * point to a saved copy of it. Nsub is the number of parenthesized regular 449 * expressions. 450 */ 451 static char * 452 compile_subst(char *p, struct s_subst *s) 453 { 454 static char lbuf[_POSIX2_LINE_MAX + 1]; 455 int asize, ref, size; 456 char c, *text, *op, *sp; 457 int sawesc = 0; 458 459 c = *p++; /* Terminator character */ 460 if (c == '\0') 461 return (NULL); 462 463 s->maxbref = 0; 464 s->linenum = linenum; 465 asize = 2 * _POSIX2_LINE_MAX + 1; 466 text = xmalloc(asize); 467 size = 0; 468 do { 469 op = sp = text + size; 470 for (; *p; p++) { 471 if (*p == '\\' || sawesc) { 472 /* 473 * If this is a continuation from the last 474 * buffer, we won't have a character to 475 * skip over. 476 */ 477 if (sawesc) 478 sawesc = 0; 479 else 480 p++; 481 482 if (*p == '\0') { 483 /* 484 * This escaped character is continued 485 * in the next part of the line. Note 486 * this fact, then cause the loop to 487 * exit w/ normal EOL case and reenter 488 * above with the new buffer. 489 */ 490 sawesc = 1; 491 p--; 492 continue; 493 } else if (strchr("123456789", *p) != NULL) { 494 *sp++ = '\\'; 495 ref = *p - '0'; 496 if (s->re != NULL && 497 ref > s->re->re_nsub) 498 err(COMPILE, 499 "\\%c not defined in the RE", *p); 500 if (s->maxbref < ref) 501 s->maxbref = ref; 502 } else if (*p == '&' || *p == '\\') 503 *sp++ = '\\'; 504 } else if (*p == c) { 505 p++; 506 *sp++ = '\0'; 507 size += sp - op; 508 s->new = xrealloc(text, size); 509 return (p); 510 } else if (*p == '\n') { 511 err(COMPILE, 512 "unescaped newline inside substitute pattern"); 513 /* NOTREACHED */ 514 } 515 *sp++ = *p; 516 } 517 size += sp - op; 518 if (asize - size < _POSIX2_LINE_MAX + 1) { 519 asize *= 2; 520 text = xrealloc(text, asize); 521 } 522 } while (cu_fgets(p = lbuf, sizeof(lbuf))); 523 err(COMPILE, "unterminated substitute in regular expression"); 524 /* NOTREACHED */ 525 } 526 527 /* 528 * Compile the flags of the s command 529 */ 530 static char * 531 compile_flags(char *p, struct s_subst *s) 532 { 533 int gn; /* True if we have seen g or n */ 534 long l; 535 char wfile[_POSIX2_LINE_MAX + 1], *q; 536 537 s->n = 1; /* Default */ 538 s->p = 0; 539 s->wfile = NULL; 540 s->wfd = -1; 541 for (gn = 0;;) { 542 EATSPACE(); /* EXTENSION */ 543 switch (*p) { 544 case 'g': 545 if (gn) 546 err(COMPILE, "more than one number or 'g' in" 547 " substitute flags"); 548 gn = 1; 549 s->n = 0; 550 break; 551 case '\0': 552 case '\n': 553 case ';': 554 return (p); 555 case 'p': 556 s->p = 1; 557 break; 558 case '1': case '2': case '3': 559 case '4': case '5': case '6': 560 case '7': case '8': case '9': 561 if (gn) 562 err(COMPILE, "more than one number or 'g' in" 563 " substitute flags"); 564 gn = 1; 565 l = strtol(p, &p, 10); 566 if (l <= 0 || l >= INT_MAX) 567 err(COMPILE, 568 "number in substitute flags out of range"); 569 s->n = (int)l; 570 continue; 571 case 'w': 572 p++; 573 #ifdef HISTORIC_PRACTICE 574 if (*p != ' ') { 575 err(WARNING, "space missing before w wfile"); 576 return (p); 577 } 578 #endif 579 EATSPACE(); 580 q = wfile; 581 while (*p) { 582 if (*p == '\n') 583 break; 584 *q++ = *p++; 585 } 586 *q = '\0'; 587 if (q == wfile) 588 err(COMPILE, "no wfile specified"); 589 s->wfile = strdup(wfile); 590 if (!aflag && (s->wfd = open(wfile, 591 O_WRONLY|O_APPEND|O_CREAT|O_TRUNC, 592 DEFFILEMODE)) == -1) 593 err(FATAL, "%s: %s", wfile, strerror(errno)); 594 return (p); 595 default: 596 err(COMPILE, 597 "bad flag in substitute command: '%c'", *p); 598 break; 599 } 600 p++; 601 } 602 } 603 604 /* 605 * Compile a translation set of strings into a lookup table. 606 */ 607 static char * 608 compile_tr(char *p, char **transtab) 609 { 610 int i; 611 char *lt, *op, *np; 612 char old[_POSIX2_LINE_MAX + 1]; 613 char new[_POSIX2_LINE_MAX + 1]; 614 615 if (*p == '\0' || *p == '\\') 616 err(COMPILE, 617 "transform pattern can not be delimited by newline or backslash"); 618 p = compile_delimited(p, old); 619 if (p == NULL) { 620 err(COMPILE, "unterminated transform source string"); 621 return (NULL); 622 } 623 p = compile_delimited(--p, new); 624 if (p == NULL) { 625 err(COMPILE, "unterminated transform target string"); 626 return (NULL); 627 } 628 EATSPACE(); 629 if (strlen(new) != strlen(old)) { 630 err(COMPILE, "transform strings are not the same length"); 631 return (NULL); 632 } 633 /* We assume characters are 8 bits */ 634 lt = xmalloc(UCHAR_MAX + 1); 635 for (i = 0; i <= UCHAR_MAX; i++) 636 lt[i] = (char)i; 637 for (op = old, np = new; *op; op++, np++) 638 lt[(u_char)*op] = *np; 639 *transtab = lt; 640 return (p); 641 } 642 643 /* 644 * Compile the text following an a, c, or i command. 645 */ 646 static char * 647 compile_text(void) 648 { 649 int asize, esc_nl, size; 650 char *text, *p, *op, *s; 651 char lbuf[_POSIX2_LINE_MAX + 1]; 652 653 asize = 2 * _POSIX2_LINE_MAX + 1; 654 text = xmalloc(asize); 655 size = 0; 656 while (cu_fgets(lbuf, sizeof(lbuf))) { 657 op = s = text + size; 658 p = lbuf; 659 EATSPACE(); 660 for (esc_nl = 0; *p != '\0'; p++) { 661 if (*p == '\\' && p[1] != '\0' && *++p == '\n') 662 esc_nl = 1; 663 *s++ = *p; 664 } 665 size += s - op; 666 if (!esc_nl) { 667 *s = '\0'; 668 break; 669 } 670 if (asize - size < _POSIX2_LINE_MAX + 1) { 671 asize *= 2; 672 text = xmalloc(asize); 673 } 674 } 675 text[size] = '\0'; 676 return (xrealloc(text, size + 1)); 677 } 678 679 /* 680 * Get an address and return a pointer to the first character after 681 * it. Fill the structure pointed to according to the address. 682 */ 683 static char * 684 compile_addr(char *p, struct s_addr *a) 685 { 686 char *end; 687 688 switch (*p) { 689 case '\\': /* Context address */ 690 ++p; 691 /* FALLTHROUGH */ 692 case '/': /* Context address */ 693 p = compile_re(p, &a->u.r); 694 if (p == NULL) 695 err(COMPILE, "unterminated regular expression"); 696 a->type = AT_RE; 697 return (p); 698 699 case '$': /* Last line */ 700 a->type = AT_LAST; 701 return (p + 1); 702 /* Line number */ 703 case '0': case '1': case '2': case '3': case '4': 704 case '5': case '6': case '7': case '8': case '9': 705 a->type = AT_LINE; 706 a->u.l = strtoul(p, &end, 10); 707 return (end); 708 default: 709 err(COMPILE, "expected context address"); 710 return (NULL); 711 } 712 } 713 714 /* 715 * duptoeol -- 716 * Return a copy of all the characters up to \n or \0. 717 */ 718 static char * 719 duptoeol(char *s, char *ctype, char **semi) 720 { 721 size_t len; 722 int ws; 723 char *start; 724 725 ws = 0; 726 if (semi) { 727 for (start = s; *s != '\0' && *s != '\n' && *s != ';'; ++s) 728 ws = isspace(*s); 729 } else { 730 for (start = s; *s != '\0' && *s != '\n'; ++s) 731 ws = isspace(*s); 732 *s = '\0'; 733 } 734 if (ws) 735 err(WARNING, "whitespace after %s", ctype); 736 len = s - start + 1; 737 if (semi) 738 *semi = s; 739 s = xmalloc(len); 740 strlcpy(s, start, len); 741 return (s); 742 } 743 744 /* 745 * Convert goto label names to addresses, and count a and r commands, in 746 * the given subset of the script. Free the memory used by labels in b 747 * and t commands (but not by :). 748 * 749 * TODO: Remove } nodes 750 */ 751 static void 752 fixuplabel(struct s_command *cp, struct s_command *end) 753 { 754 755 for (; cp != end; cp = cp->next) 756 switch (cp->code) { 757 case 'a': 758 case 'r': 759 appendnum++; 760 break; 761 case 'b': 762 case 't': 763 /* Resolve branch target. */ 764 if (cp->t == NULL) { 765 cp->u.c = NULL; 766 break; 767 } 768 if ((cp->u.c = findlabel(cp->t)) == NULL) 769 err(COMPILE2, "undefined label '%s'", cp->t); 770 free(cp->t); 771 break; 772 case '{': 773 /* Do interior commands. */ 774 fixuplabel(cp->u.c, cp->next); 775 break; 776 } 777 } 778 779 /* 780 * Associate the given command label for later lookup. 781 */ 782 static void 783 enterlabel(struct s_command *cp) 784 { 785 struct labhash **lhp, *lh; 786 u_char *p; 787 u_int h, c; 788 789 for (h = 0, p = (u_char *)cp->t; (c = *p) != 0; p++) 790 h = (h << 5) + h + c; 791 lhp = &labels[h & LHMASK]; 792 for (lh = *lhp; lh != NULL; lh = lh->lh_next) 793 if (lh->lh_hash == h && strcmp(cp->t, lh->lh_cmd->t) == 0) 794 err(COMPILE2, "duplicate label '%s'", cp->t); 795 lh = xmalloc(sizeof *lh); 796 lh->lh_next = *lhp; 797 lh->lh_hash = h; 798 lh->lh_cmd = cp; 799 lh->lh_ref = 0; 800 *lhp = lh; 801 } 802 803 /* 804 * Find the label contained in the command l in the command linked 805 * list cp. L is excluded from the search. Return NULL if not found. 806 */ 807 static struct s_command * 808 findlabel(char *name) 809 { 810 struct labhash *lh; 811 u_char *p; 812 u_int h, c; 813 814 for (h = 0, p = (u_char *)name; (c = *p) != 0; p++) 815 h = (h << 5) + h + c; 816 for (lh = labels[h & LHMASK]; lh != NULL; lh = lh->lh_next) { 817 if (lh->lh_hash == h && strcmp(name, lh->lh_cmd->t) == 0) { 818 lh->lh_ref = 1; 819 return (lh->lh_cmd); 820 } 821 } 822 return (NULL); 823 } 824 825 /* 826 * Warn about any unused labels. As a side effect, release the label hash 827 * table space. 828 */ 829 static void 830 uselabel(void) 831 { 832 struct labhash *lh, *next; 833 int i; 834 835 for (i = 0; i < LHSZ; i++) { 836 for (lh = labels[i]; lh != NULL; lh = next) { 837 next = lh->lh_next; 838 if (!lh->lh_ref) 839 err(WARNING, "unused label '%s'", 840 lh->lh_cmd->t); 841 free(lh); 842 } 843 } 844 } 845