1 /* $OpenBSD: compile.c,v 1.53 2024/07/17 20:57:15 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 <err.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 *); 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 = xreallocarray(NULL, appendnum, sizeof(struct s_appends)); 132 match = xreallocarray(NULL, maxnsub + 1, sizeof(regmatch_t)); 133 } 134 135 #define EATSPACE() do { \ 136 if (p) \ 137 while (isascii((unsigned char)*p) && \ 138 isspace((unsigned char)*p)) \ 139 p++; \ 140 } while (0) 141 142 static struct s_command ** 143 compile_stream(struct s_command **link) 144 { 145 char *p; 146 static char *lbuf; /* To avoid excessive malloc calls */ 147 static size_t bufsize; 148 struct s_command *cmd, *cmd2, *stack; 149 struct s_format *fp; 150 int naddr; /* Number of addresses */ 151 152 stack = 0; 153 for (;;) { 154 if ((p = cu_getline(&lbuf, &bufsize)) == NULL) { 155 if (stack != 0) 156 error("unexpected EOF (pending }'s)"); 157 return (link); 158 } 159 160 semicolon: EATSPACE(); 161 if (*p == '#' || *p == '\0') 162 continue; 163 if (*p == ';') { 164 p++; 165 goto semicolon; 166 } 167 *link = cmd = xmalloc(sizeof(struct s_command)); 168 link = &cmd->next; 169 cmd->nonsel = cmd->inrange = 0; 170 /* First parse the addresses */ 171 naddr = 0; 172 173 /* Valid characters to start an address */ 174 #define addrchar(c) (strchr("0123456789/\\$", (c))) 175 if (addrchar(*p)) { 176 naddr++; 177 cmd->a1 = xmalloc(sizeof(struct s_addr)); 178 p = compile_addr(p, cmd->a1); 179 EATSPACE(); /* EXTENSION */ 180 if (*p == ',') { 181 p++; 182 EATSPACE(); /* EXTENSION */ 183 naddr++; 184 cmd->a2 = xmalloc(sizeof(struct s_addr)); 185 p = compile_addr(p, cmd->a2); 186 EATSPACE(); 187 } else { 188 cmd->a2 = 0; 189 } 190 } else { 191 cmd->a1 = cmd->a2 = 0; 192 } 193 194 nonsel: /* Now parse the command */ 195 if (!*p) 196 error("command expected"); 197 cmd->code = *p; 198 for (fp = cmd_fmts; fp->code; fp++) 199 if (fp->code == *p) 200 break; 201 if (!fp->code) 202 error("invalid command code %c", *p); 203 if (naddr > fp->naddr) 204 error("command %c expects up to %d address(es)," 205 " found %d", *p, fp->naddr, naddr); 206 switch (fp->args) { 207 case NONSEL: /* ! */ 208 p++; 209 EATSPACE(); 210 cmd->nonsel = 1; 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 error("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 error("extra characters at the end of %c" 243 " command", cmd->code); 244 break; 245 case TEXT: /* a c i */ 246 p++; 247 EATSPACE(); 248 if (*p != '\\') 249 error("command %c expects \\ followed by text", 250 cmd->code); 251 p++; 252 EATSPACE(); 253 if (*p) 254 error("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 error("filename expected"); 265 cmd->t = duptoeol(p, "w command", NULL); 266 if (aflag) { 267 cmd->u.fd = -1; 268 pledge_wpath = 1; 269 } 270 else if ((cmd->u.fd = open(p, 271 O_WRONLY|O_APPEND|O_CREAT|O_TRUNC, 272 DEFFILEMODE)) == -1) 273 err(1, "%s", p); 274 break; 275 case RFILE: /* r */ 276 pledge_rpath = 1; 277 p++; 278 EATSPACE(); 279 if (*p == '\0') 280 error("filename expected"); 281 cmd->t = duptoeol(p, "read command", NULL); 282 break; 283 case BRANCH: /* b t */ 284 p++; 285 EATSPACE(); 286 if (*p == '\0' || *p == ';') 287 cmd->t = NULL; 288 else 289 cmd->t = duptoeol(p, "branch", &p); 290 if (*p == ';') { 291 p++; 292 goto semicolon; 293 } 294 break; 295 case LABEL: /* : */ 296 p++; 297 EATSPACE(); 298 cmd->t = duptoeol(p, "label", &p); 299 if (strlen(cmd->t) == 0) 300 error("empty label"); 301 enterlabel(cmd); 302 if (*p == ';') { 303 p++; 304 goto semicolon; 305 } 306 break; 307 case SUBST: /* s */ 308 p++; 309 if (*p == '\0' || *p == '\\') 310 error("substitute pattern can not be" 311 " delimited by newline or backslash"); 312 cmd->u.s = xmalloc(sizeof(struct s_subst)); 313 p = compile_re(p, &cmd->u.s->re); 314 if (p == NULL) 315 error("unterminated substitute pattern"); 316 --p; 317 p = compile_subst(p, cmd->u.s); 318 p = compile_flags(p, cmd->u.s); 319 EATSPACE(); 320 if (*p == ';') { 321 p++; 322 link = &cmd->next; 323 goto semicolon; 324 } 325 break; 326 case TR: /* y */ 327 p++; 328 p = compile_tr(p, (char **)&cmd->u.y); 329 EATSPACE(); 330 if (*p == ';') { 331 p++; 332 link = &cmd->next; 333 goto semicolon; 334 } 335 if (*p) 336 error("extra text at the end of a" 337 " transform command"); 338 break; 339 } 340 } 341 } 342 343 /* 344 * Get a delimited string. P points to the delimiter of the string; d points 345 * to a buffer area. Newline and delimiter escapes are processed; other 346 * escapes are ignored. 347 * 348 * Returns a pointer to the first character after the final delimiter or NULL 349 * in the case of a non-terminated string. The character array d is filled 350 * with the processed string. 351 */ 352 static char * 353 compile_delimited(char *p, char *d) 354 { 355 char c; 356 357 c = *p++; 358 if (c == '\0') 359 return (NULL); 360 else if (c == '\\') 361 error("\\ can not be used as a string delimiter"); 362 else if (c == '\n') 363 error("newline can not be used as a string delimiter"); 364 365 while (p[0]) { 366 /* Unescaped delimiter: We are done. */ 367 if (p[0] == c) { 368 *d = '\0'; 369 return p + 1; 370 } 371 if (p[0] == '\\') { 372 /* Escaped delimiter: Skip the backslash. */ 373 if (p[1] == c) { 374 p++; 375 } else { 376 /* Backslash-n: Match linefeed. */ 377 if (p[1] == 'n') { 378 *d++ = '\n'; 379 p += 2; 380 /* Other escapes remain unchanged. */ 381 } else { 382 *d++ = *p++; 383 *d++ = *p++; 384 } 385 continue; 386 } 387 } 388 if (p[0] != '[') 389 *d++ = *p++; 390 /* 391 * Bracket expression: 392 * It may contain the delimiter without escaping. 393 */ 394 else if ((d = compile_ccl(&p, d)) == NULL) 395 error("unbalanced brackets ([])"); 396 } 397 return NULL; 398 } 399 400 401 /* compile_ccl: expand a POSIX character class */ 402 static char * 403 compile_ccl(char **sp, char *t) 404 { 405 int c, d; 406 char *s = *sp; 407 408 *t++ = *s++; 409 if (*s == '^') 410 *t++ = *s++; 411 if (*s == ']') 412 *t++ = *s++; 413 for (; *s && (*t = *s) != ']'; s++, t++) 414 if (*s == '[' && ((d = *(s+1)) == '.' || d == ':' || d == '=')) { 415 *++t = *++s, t++, s++; 416 for (c = *s; (*t = *s) != ']' || c != d; s++, t++) 417 if ((c = *s) == '\0') 418 return NULL; 419 } else if (*s == '\\' && s[1] == 'n') { 420 *t = '\n'; 421 s++; 422 } 423 if (*s == ']') { 424 *sp = ++s; 425 return (++t); 426 } else { 427 return (NULL); 428 } 429 } 430 431 /* 432 * Get a regular expression. P points to the delimiter of the regular 433 * expression; repp points to the address of a regexp pointer. Newline 434 * and delimiter escapes are processed; other escapes are ignored. 435 * Returns a pointer to the first character after the final delimiter 436 * or NULL in the case of a non terminated regular expression. The regexp 437 * pointer is set to the compiled regular expression. 438 * Cflags are passed to regcomp. 439 */ 440 static char * 441 compile_re(char *p, regex_t **repp) 442 { 443 int eval; 444 char *re; 445 446 re = xmalloc(strlen(p) + 1); /* strlen(re) <= strlen(p) */ 447 p = compile_delimited(p, re); 448 if (p && strlen(re) == 0) { 449 *repp = NULL; 450 free(re); 451 return (p); 452 } 453 *repp = xmalloc(sizeof(regex_t)); 454 if (p && (eval = regcomp(*repp, re, Eflag ? REG_EXTENDED : 0)) != 0) 455 error("RE error: %s", strregerror(eval, *repp)); 456 if (maxnsub < (*repp)->re_nsub) 457 maxnsub = (*repp)->re_nsub; 458 free(re); 459 return (p); 460 } 461 462 /* 463 * Compile the substitution string of a regular expression and set res to 464 * point to a saved copy of it. Nsub is the number of parenthesized regular 465 * expressions. 466 */ 467 static char * 468 compile_subst(char *p, struct s_subst *s) 469 { 470 static char *lbuf; 471 static size_t bufsize; 472 size_t asize, ref, size; 473 char c, *text, *op, *sp; 474 int sawesc = 0; 475 476 c = *p++; /* Terminator character */ 477 if (c == '\0') 478 return (NULL); 479 480 s->maxbref = 0; 481 s->linenum = linenum; 482 text = NULL; 483 asize = size = 0; 484 do { 485 size_t len = ROUNDLEN(strlen(p) + 1); 486 if (asize - size < len) { 487 do { 488 asize += len; 489 } while (asize - size < len); 490 text = xrealloc(text, asize); 491 } 492 op = sp = text + size; 493 for (; *p; p++) { 494 if (*p == '\\' || sawesc) { 495 /* 496 * If this is a continuation from the last 497 * buffer, we won't have a character to 498 * skip over. 499 */ 500 if (sawesc) 501 sawesc = 0; 502 else 503 p++; 504 505 if (*p == '\0') { 506 /* 507 * This escaped character is continued 508 * in the next part of the line. Note 509 * this fact, then cause the loop to 510 * exit w/ normal EOL case and reenter 511 * above with the new buffer. 512 */ 513 sawesc = 1; 514 p--; 515 continue; 516 } else if (strchr("123456789", *p) != NULL) { 517 *sp++ = '\\'; 518 ref = *p - '0'; 519 if (s->re != NULL && 520 ref > s->re->re_nsub) 521 error("\\%c not defined in the" 522 " RE", *p); 523 if (s->maxbref < ref) 524 s->maxbref = ref; 525 } else if (*p == '&' || *p == '\\') 526 *sp++ = '\\'; 527 } else if (*p == c) { 528 p++; 529 *sp++ = '\0'; 530 size += sp - op; 531 s->new = xrealloc(text, size); 532 return (p); 533 } else if (*p == '\n') { 534 error("unescaped newline inside substitute" 535 " pattern"); 536 } 537 *sp++ = *p; 538 } 539 size += sp - op; 540 } while ((p = cu_getline(&lbuf, &bufsize))); 541 error("unterminated substitute in regular expression"); 542 } 543 544 /* 545 * Compile the flags of the s command 546 */ 547 static char * 548 compile_flags(char *p, struct s_subst *s) 549 { 550 int gn; /* True if we have seen g or n */ 551 long l; 552 553 s->n = 1; /* Default */ 554 s->p = 0; 555 s->wfile = NULL; 556 s->wfd = -1; 557 for (gn = 0;;) { 558 EATSPACE(); /* EXTENSION */ 559 switch (*p) { 560 case 'g': 561 if (gn) 562 error("more than one number or 'g' in" 563 " substitute flags"); 564 gn = 1; 565 s->n = 0; 566 break; 567 case '\0': 568 case '\n': 569 case ';': 570 return (p); 571 case 'p': 572 s->p = 1; 573 break; 574 case '1': case '2': case '3': 575 case '4': case '5': case '6': 576 case '7': case '8': case '9': 577 if (gn) 578 error("more than one number or 'g' in" 579 " substitute flags"); 580 gn = 1; 581 l = strtol(p, &p, 10); 582 if (l <= 0 || l >= INT_MAX) 583 error("number in substitute flags out of" 584 " range"); 585 s->n = (int)l; 586 continue; 587 case 'w': 588 p++; 589 EATSPACE(); 590 if (*p == '\0') 591 error("filename expected"); 592 s->wfile = duptoeol(p, "s command w flag", NULL); 593 *p = '\0'; 594 if (aflag) 595 pledge_wpath = 1; 596 else if ((s->wfd = open(s->wfile, 597 O_WRONLY|O_APPEND|O_CREAT|O_TRUNC, 598 DEFFILEMODE)) == -1) 599 err(1, "%s", s->wfile); 600 return (p); 601 default: 602 error("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 *old, char **transtab) 614 { 615 int i; 616 char delimiter, check[UCHAR_MAX + 1]; 617 char *new, *end; 618 619 memset(check, 0, sizeof(check)); 620 delimiter = *old; 621 if (delimiter == '\\') 622 error("\\ can not be used as a string delimiter"); 623 else if (delimiter == '\n' || delimiter == '\0') 624 error("newline can not be used as a string delimiter"); 625 626 new = old++; 627 do { 628 if ((new = strchr(new + 1, delimiter)) == NULL) 629 error("unterminated transform source string"); 630 } while (*(new - 1) == '\\' && *(new -2) != '\\'); 631 *new = '\0'; 632 end = new++; 633 do { 634 if ((end = strchr(end + 1, delimiter)) == NULL) 635 error("unterminated transform target string"); 636 } while (*(end -1) == '\\' && *(end -2) != '\\'); 637 *end = '\0'; 638 639 /* We assume characters are 8 bits */ 640 *transtab = xmalloc(UCHAR_MAX + 1); 641 for (i = 0; i <= UCHAR_MAX; i++) 642 (*transtab)[i] = (char)i; 643 644 while (*old != '\0' && *new != '\0') { 645 if (*old == '\\') { 646 old++; 647 if (*old == 'n') 648 *old = '\n'; 649 else if (*old != delimiter && *old != '\\') 650 error("Unexpected character after backslash"); 651 } 652 if (*new == '\\') { 653 new++; 654 if (*new == 'n') 655 *new = '\n'; 656 else if (*new != delimiter && *new != '\\') 657 error("Unexpected character after backslash"); 658 } 659 if (check[(u_char) *old] == 1) 660 error("Repeated character in source string"); 661 check[(u_char) *old] = 1; 662 (*transtab)[(u_char) *old++] = *new++; 663 } 664 if (*old != '\0' || *new != '\0') 665 error("transform strings are not the same length"); 666 return end + 1; 667 } 668 669 /* 670 * Compile the text following an a, c, or i command. 671 */ 672 static char * 673 compile_text(void) 674 { 675 size_t asize, size, bufsize; 676 char *lbuf, *text, *p, *op, *s; 677 int esc_nl; 678 679 lbuf = text = NULL; 680 asize = size = 0; 681 while ((p = cu_getline(&lbuf, &bufsize))) { 682 size_t len = ROUNDLEN(strlen(p) + 1); 683 if (asize - size < len) { 684 do { 685 asize += len; 686 } while (asize - size < len); 687 text = xrealloc(text, asize); 688 } 689 op = s = text + size; 690 for (esc_nl = 0; *p != '\0'; p++) { 691 if (*p == '\\' && p[1] != '\0' && *++p == '\n') 692 esc_nl = 1; 693 *s++ = *p; 694 } 695 size += s - op; 696 if (!esc_nl) { 697 *s = '\0'; 698 break; 699 } 700 } 701 free(lbuf); 702 text = xrealloc(text, size + 1); 703 text[size] = '\0'; 704 return (text); 705 } 706 707 /* 708 * Get an address and return a pointer to the first character after 709 * it. Fill the structure pointed to according to the address. 710 */ 711 static char * 712 compile_addr(char *p, struct s_addr *a) 713 { 714 char *end; 715 716 switch (*p) { 717 case '\\': /* Context address */ 718 ++p; 719 /* FALLTHROUGH */ 720 case '/': /* Context address */ 721 p = compile_re(p, &a->u.r); 722 if (p == NULL) 723 error("unterminated regular expression"); 724 a->type = AT_RE; 725 return (p); 726 727 case '$': /* Last line */ 728 a->type = AT_LAST; 729 return (p + 1); 730 /* Line number */ 731 case '0': case '1': case '2': case '3': case '4': 732 case '5': case '6': case '7': case '8': case '9': 733 a->type = AT_LINE; 734 a->u.l = strtoul(p, &end, 10); 735 return (end); 736 default: 737 error("expected context address"); 738 return (NULL); 739 } 740 } 741 742 /* 743 * duptoeol -- 744 * Return a copy of all the characters up to \n or \0. 745 */ 746 static char * 747 duptoeol(char *s, char *ctype, char **semi) 748 { 749 size_t len; 750 int ws; 751 char *start; 752 753 ws = 0; 754 if (semi) { 755 for (start = s; *s != '\0' && *s != '\n' && *s != ';'; ++s) 756 ws = isspace((unsigned char)*s); 757 } else { 758 for (start = s; *s != '\0' && *s != '\n'; ++s) 759 ws = isspace((unsigned char)*s); 760 *s = '\0'; 761 } 762 if (ws) 763 warning("whitespace after %s", ctype); 764 len = s - start + 1; 765 if (semi) 766 *semi = s; 767 s = xmalloc(len); 768 strlcpy(s, start, len); 769 return (s); 770 } 771 772 /* 773 * Convert goto label names to addresses, and count a and r commands, in 774 * the given subset of the script. Free the memory used by labels in b 775 * and t commands (but not by :). 776 * 777 * TODO: Remove } nodes 778 */ 779 static void 780 fixuplabel(struct s_command *cp, struct s_command *end) 781 { 782 783 for (; cp != end; cp = cp->next) 784 switch (cp->code) { 785 case 'a': 786 case 'r': 787 appendnum++; 788 break; 789 case 'b': 790 case 't': 791 /* Resolve branch target. */ 792 if (cp->t == NULL) { 793 cp->u.c = NULL; 794 break; 795 } 796 if ((cp->u.c = findlabel(cp->t)) == NULL) 797 error("undefined label '%s'", cp->t); 798 free(cp->t); 799 break; 800 case '{': 801 /* Do interior commands. */ 802 fixuplabel(cp->u.c, cp->next); 803 break; 804 } 805 } 806 807 /* 808 * Associate the given command label for later lookup. 809 */ 810 static void 811 enterlabel(struct s_command *cp) 812 { 813 struct labhash **lhp, *lh; 814 u_char *p; 815 u_int h, c; 816 817 for (h = 0, p = (u_char *)cp->t; (c = *p) != 0; p++) 818 h = (h << 5) + h + c; 819 lhp = &labels[h & LHMASK]; 820 for (lh = *lhp; lh != NULL; lh = lh->lh_next) 821 if (lh->lh_hash == h && strcmp(cp->t, lh->lh_cmd->t) == 0) 822 error("duplicate label '%s'", cp->t); 823 lh = xmalloc(sizeof *lh); 824 lh->lh_next = *lhp; 825 lh->lh_hash = h; 826 lh->lh_cmd = cp; 827 lh->lh_ref = 0; 828 *lhp = lh; 829 } 830 831 /* 832 * Find the label contained in the command l in the command linked 833 * list cp. L is excluded from the search. Return NULL if not found. 834 */ 835 static struct s_command * 836 findlabel(char *name) 837 { 838 struct labhash *lh; 839 u_char *p; 840 u_int h, c; 841 842 for (h = 0, p = (u_char *)name; (c = *p) != 0; p++) 843 h = (h << 5) + h + c; 844 for (lh = labels[h & LHMASK]; lh != NULL; lh = lh->lh_next) { 845 if (lh->lh_hash == h && strcmp(name, lh->lh_cmd->t) == 0) { 846 lh->lh_ref = 1; 847 return (lh->lh_cmd); 848 } 849 } 850 return (NULL); 851 } 852 853 /* 854 * Warn about any unused labels. As a side effect, release the label hash 855 * table space. 856 */ 857 static void 858 uselabel(void) 859 { 860 struct labhash *lh, *next; 861 int i; 862 863 for (i = 0; i < LHSZ; i++) { 864 for (lh = labels[i]; lh != NULL; lh = next) { 865 next = lh->lh_next; 866 if (!lh->lh_ref) 867 warning("unused label '%s'", 868 lh->lh_cmd->t); 869 free(lh); 870 } 871 } 872 } 873