1 /* $OpenBSD: compile.c,v 1.41 2017/01/20 10:26:16 krw 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 = 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_fgets(&lbuf, &bufsize)) == NULL) { 155 if (stack != 0) 156 error(COMPILE, "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(COMPILE, "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(COMPILE, "invalid command code %c", *p); 203 if (naddr > fp->naddr) 204 error(COMPILE, 205 "command %c expects up to %d address(es), found %d", 206 *p, fp->naddr, naddr); 207 switch (fp->args) { 208 case NONSEL: /* ! */ 209 p++; 210 EATSPACE(); 211 cmd->nonsel = 1; 212 goto nonsel; 213 case GROUP: /* { */ 214 p++; 215 EATSPACE(); 216 cmd->next = stack; 217 stack = cmd; 218 link = &cmd->u.c; 219 if (*p) 220 goto semicolon; 221 break; 222 case ENDGROUP: 223 /* 224 * Short-circuit command processing, since end of 225 * group is really just a noop. 226 */ 227 cmd->nonsel = 1; 228 if (stack == 0) 229 error(COMPILE, "unexpected }"); 230 cmd2 = stack; 231 stack = cmd2->next; 232 cmd2->next = cmd; 233 /*FALLTHROUGH*/ 234 case EMPTY: /* d D g G h H l n N p P q x = \0 */ 235 p++; 236 EATSPACE(); 237 if (*p == ';') { 238 p++; 239 link = &cmd->next; 240 goto semicolon; 241 } 242 if (*p) 243 error(COMPILE, 244 "extra characters at the end of %c command", cmd->code); 245 break; 246 case TEXT: /* a c i */ 247 p++; 248 EATSPACE(); 249 if (*p != '\\') 250 error(COMPILE, "command %c expects \\ followed by" 251 " text", cmd->code); 252 p++; 253 EATSPACE(); 254 if (*p) 255 error(COMPILE, "extra characters after \\ at the" 256 " end of %c command", cmd->code); 257 cmd->t = compile_text(); 258 break; 259 case COMMENT: /* \0 # */ 260 break; 261 case WFILE: /* w */ 262 p++; 263 EATSPACE(); 264 if (*p == '\0') 265 error(COMPILE, "filename expected"); 266 cmd->t = duptoeol(p, "w command", NULL); 267 if (aflag) 268 cmd->u.fd = -1; 269 else if ((cmd->u.fd = open(p, 270 O_WRONLY|O_APPEND|O_CREAT|O_TRUNC, 271 DEFFILEMODE)) == -1) 272 error(FATAL, "%s: %s", p, strerror(errno)); 273 break; 274 case RFILE: /* r */ 275 p++; 276 EATSPACE(); 277 cmd->t = duptoeol(p, "read command", NULL); 278 break; 279 case BRANCH: /* b t */ 280 p++; 281 EATSPACE(); 282 if (*p == '\0') 283 cmd->t = NULL; 284 else 285 cmd->t = duptoeol(p, "branch", &p); 286 if (*p == ';') { 287 p++; 288 goto semicolon; 289 } 290 break; 291 case LABEL: /* : */ 292 p++; 293 EATSPACE(); 294 cmd->t = duptoeol(p, "label", &p); 295 if (strlen(cmd->t) == 0) 296 error(COMPILE, "empty label"); 297 enterlabel(cmd); 298 if (*p == ';') { 299 p++; 300 goto semicolon; 301 } 302 break; 303 case SUBST: /* s */ 304 p++; 305 if (*p == '\0' || *p == '\\') 306 error(COMPILE, "substitute pattern can not be" 307 " delimited by newline or backslash"); 308 cmd->u.s = xmalloc(sizeof(struct s_subst)); 309 p = compile_re(p, &cmd->u.s->re); 310 if (p == NULL) 311 error(COMPILE, "unterminated substitute pattern"); 312 --p; 313 p = compile_subst(p, cmd->u.s); 314 p = compile_flags(p, cmd->u.s); 315 EATSPACE(); 316 if (*p == ';') { 317 p++; 318 link = &cmd->next; 319 goto semicolon; 320 } 321 break; 322 case TR: /* y */ 323 p++; 324 p = compile_tr(p, (char **)&cmd->u.y); 325 EATSPACE(); 326 if (*p == ';') { 327 p++; 328 link = &cmd->next; 329 goto semicolon; 330 } 331 if (*p) 332 error(COMPILE, "extra text at the end of a" 333 " transform command"); 334 break; 335 } 336 } 337 } 338 339 /* 340 * Get a delimited string. P points to the delimeter of the string; d points 341 * to a buffer area. Newline and delimiter escapes are processed; other 342 * escapes are ignored. 343 * 344 * Returns a pointer to the first character after the final delimiter or NULL 345 * in the case of a non-terminated string. The character array d is filled 346 * with the processed string. 347 */ 348 static char * 349 compile_delimited(char *p, char *d, int is_tr) 350 { 351 char c; 352 353 c = *p++; 354 if (c == '\0') 355 return (NULL); 356 else if (c == '\\') 357 error(COMPILE, "\\ can not be used as a string delimiter"); 358 else if (c == '\n') 359 error(COMPILE, "newline can not be used as a string delimiter"); 360 while (*p) { 361 if (*p == '[' && *p != c) { 362 if ((d = compile_ccl(&p, d)) == NULL) 363 error(COMPILE, "unbalanced brackets ([])"); 364 continue; 365 } else if (*p == '\\' && p[1] == '[') { 366 *d++ = *p++; 367 } else if (*p == '\\' && p[1] == c) { 368 p++; 369 } else if (*p == '\\' && p[1] == 'n') { 370 *d++ = '\n'; 371 p += 2; 372 continue; 373 } else if (*p == '\\' && p[1] == '\\') { 374 if (is_tr) 375 p++; 376 else 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; 432 433 re = xmalloc(strlen(p) + 1); /* strlen(re) <= strlen(p) */ 434 p = compile_delimited(p, re, 0); 435 if (p && strlen(re) == 0) { 436 *repp = NULL; 437 free(re); 438 return (p); 439 } 440 *repp = xmalloc(sizeof(regex_t)); 441 if (p && (eval = regcomp(*repp, re, Eflag ? REG_EXTENDED : 0)) != 0) 442 error(COMPILE, "RE error: %s", strregerror(eval, *repp)); 443 if (maxnsub < (*repp)->re_nsub) 444 maxnsub = (*repp)->re_nsub; 445 free(re); 446 return (p); 447 } 448 449 /* 450 * Compile the substitution string of a regular expression and set res to 451 * point to a saved copy of it. Nsub is the number of parenthesized regular 452 * expressions. 453 */ 454 static char * 455 compile_subst(char *p, struct s_subst *s) 456 { 457 static char *lbuf; 458 static size_t bufsize; 459 int asize, ref, size; 460 char c, *text, *op, *sp; 461 int sawesc = 0; 462 463 c = *p++; /* Terminator character */ 464 if (c == '\0') 465 return (NULL); 466 467 s->maxbref = 0; 468 s->linenum = linenum; 469 text = NULL; 470 asize = size = 0; 471 do { 472 size_t len = ROUNDLEN(strlen(p) + 1); 473 if (asize - size < len) { 474 do { 475 asize += len; 476 } while (asize - size < len); 477 text = xrealloc(text, asize); 478 } 479 op = sp = text + size; 480 for (; *p; p++) { 481 if (*p == '\\' || sawesc) { 482 /* 483 * If this is a continuation from the last 484 * buffer, we won't have a character to 485 * skip over. 486 */ 487 if (sawesc) 488 sawesc = 0; 489 else 490 p++; 491 492 if (*p == '\0') { 493 /* 494 * This escaped character is continued 495 * in the next part of the line. Note 496 * this fact, then cause the loop to 497 * exit w/ normal EOL case and reenter 498 * above with the new buffer. 499 */ 500 sawesc = 1; 501 p--; 502 continue; 503 } else if (strchr("123456789", *p) != NULL) { 504 *sp++ = '\\'; 505 ref = *p - '0'; 506 if (s->re != NULL && 507 ref > s->re->re_nsub) 508 error(COMPILE, 509 "\\%c not defined in the RE", *p); 510 if (s->maxbref < ref) 511 s->maxbref = ref; 512 } else if (*p == '&' || *p == '\\') 513 *sp++ = '\\'; 514 } else if (*p == c) { 515 p++; 516 *sp++ = '\0'; 517 size += sp - op; 518 s->new = xrealloc(text, size); 519 return (p); 520 } else if (*p == '\n') { 521 error(COMPILE, 522 "unescaped newline inside substitute pattern"); 523 } 524 *sp++ = *p; 525 } 526 size += sp - op; 527 } while ((p = cu_fgets(&lbuf, &bufsize))); 528 error(COMPILE, "unterminated substitute in regular expression"); 529 } 530 531 /* 532 * Compile the flags of the s command 533 */ 534 static char * 535 compile_flags(char *p, struct s_subst *s) 536 { 537 int gn; /* True if we have seen g or n */ 538 long l; 539 char wfile[PATH_MAX], *q, *eq; 540 541 s->n = 1; /* Default */ 542 s->p = 0; 543 s->wfile = NULL; 544 s->wfd = -1; 545 for (gn = 0;;) { 546 EATSPACE(); /* EXTENSION */ 547 switch (*p) { 548 case 'g': 549 if (gn) 550 error(COMPILE, "more than one number or 'g' in" 551 " substitute flags"); 552 gn = 1; 553 s->n = 0; 554 break; 555 case '\0': 556 case '\n': 557 case ';': 558 return (p); 559 case 'p': 560 s->p = 1; 561 break; 562 case '1': case '2': case '3': 563 case '4': case '5': case '6': 564 case '7': case '8': case '9': 565 if (gn) 566 error(COMPILE, "more than one number or 'g' in" 567 " substitute flags"); 568 gn = 1; 569 l = strtol(p, &p, 10); 570 if (l <= 0 || l >= INT_MAX) 571 error(COMPILE, 572 "number in substitute flags out of range"); 573 s->n = (int)l; 574 continue; 575 case 'w': 576 p++; 577 #ifdef HISTORIC_PRACTICE 578 if (*p != ' ') { 579 warning("space missing before w wfile"); 580 return (p); 581 } 582 #endif 583 EATSPACE(); 584 q = wfile; 585 eq = wfile + sizeof(wfile) - 1; 586 while (*p) { 587 if (*p == '\n') 588 break; 589 if (q >= eq) 590 error(COMPILE, "wfile too long"); 591 *q++ = *p++; 592 } 593 *q = '\0'; 594 if (q == wfile) 595 error(COMPILE, "no wfile specified"); 596 s->wfile = strdup(wfile); 597 if (!aflag && (s->wfd = open(wfile, 598 O_WRONLY|O_APPEND|O_CREAT|O_TRUNC, 599 DEFFILEMODE)) == -1) 600 error(FATAL, "%s: %s", wfile, strerror(errno)); 601 return (p); 602 default: 603 error(COMPILE, 604 "bad flag in substitute command: '%c'", *p); 605 break; 606 } 607 p++; 608 } 609 } 610 611 /* 612 * Compile a translation set of strings into a lookup table. 613 */ 614 static char * 615 compile_tr(char *p, char **transtab) 616 { 617 int i; 618 char *lt, *op, *np; 619 char *old = NULL, *new = NULL; 620 621 if (*p == '\0' || *p == '\\') 622 error(COMPILE, 623 "transform pattern can not be delimited by newline or backslash"); 624 old = xmalloc(strlen(p) + 1); 625 p = compile_delimited(p, old, 1); 626 if (p == NULL) { 627 error(COMPILE, "unterminated transform source string"); 628 goto bad; 629 } 630 new = xmalloc(strlen(p) + 1); 631 p = compile_delimited(--p, new, 1); 632 if (p == NULL) { 633 error(COMPILE, "unterminated transform target string"); 634 goto bad; 635 } 636 EATSPACE(); 637 if (strlen(new) != strlen(old)) { 638 error(COMPILE, "transform strings are not the same length"); 639 goto bad; 640 } 641 /* We assume characters are 8 bits */ 642 lt = xmalloc(UCHAR_MAX + 1); 643 for (i = 0; i <= UCHAR_MAX; i++) 644 lt[i] = (char)i; 645 for (op = old, np = new; *op; op++, np++) 646 lt[(u_char)*op] = *np; 647 *transtab = lt; 648 free(old); 649 free(new); 650 return (p); 651 bad: 652 free(old); 653 free(new); 654 return (NULL); 655 } 656 657 /* 658 * Compile the text following an a, c, or i command. 659 */ 660 static char * 661 compile_text(void) 662 { 663 int asize, esc_nl, size; 664 char *lbuf, *text, *p, *op, *s; 665 size_t bufsize; 666 667 lbuf = text = NULL; 668 asize = size = 0; 669 while ((p = cu_fgets(&lbuf, &bufsize))) { 670 size_t len = ROUNDLEN(strlen(p) + 1); 671 if (asize - size < len) { 672 do { 673 asize += len; 674 } while (asize - size < len); 675 text = xrealloc(text, asize); 676 } 677 op = s = text + size; 678 for (esc_nl = 0; *p != '\0'; p++) { 679 if (*p == '\\' && p[1] != '\0' && *++p == '\n') 680 esc_nl = 1; 681 *s++ = *p; 682 } 683 size += s - op; 684 if (!esc_nl) { 685 *s = '\0'; 686 break; 687 } 688 } 689 free(lbuf); 690 text = xrealloc(text, size + 1); 691 text[size] = '\0'; 692 return (text); 693 } 694 695 /* 696 * Get an address and return a pointer to the first character after 697 * it. Fill the structure pointed to according to the address. 698 */ 699 static char * 700 compile_addr(char *p, struct s_addr *a) 701 { 702 char *end; 703 704 switch (*p) { 705 case '\\': /* Context address */ 706 ++p; 707 /* FALLTHROUGH */ 708 case '/': /* Context address */ 709 p = compile_re(p, &a->u.r); 710 if (p == NULL) 711 error(COMPILE, "unterminated regular expression"); 712 a->type = AT_RE; 713 return (p); 714 715 case '$': /* Last line */ 716 a->type = AT_LAST; 717 return (p + 1); 718 /* Line number */ 719 case '0': case '1': case '2': case '3': case '4': 720 case '5': case '6': case '7': case '8': case '9': 721 a->type = AT_LINE; 722 a->u.l = strtoul(p, &end, 10); 723 return (end); 724 default: 725 error(COMPILE, "expected context address"); 726 return (NULL); 727 } 728 } 729 730 /* 731 * duptoeol -- 732 * Return a copy of all the characters up to \n or \0. 733 */ 734 static char * 735 duptoeol(char *s, char *ctype, char **semi) 736 { 737 size_t len; 738 int ws; 739 char *start; 740 741 ws = 0; 742 if (semi) { 743 for (start = s; *s != '\0' && *s != '\n' && *s != ';'; ++s) 744 ws = isspace((unsigned char)*s); 745 } else { 746 for (start = s; *s != '\0' && *s != '\n'; ++s) 747 ws = isspace((unsigned char)*s); 748 *s = '\0'; 749 } 750 if (ws) 751 warning("whitespace after %s", ctype); 752 len = s - start + 1; 753 if (semi) 754 *semi = s; 755 s = xmalloc(len); 756 strlcpy(s, start, len); 757 return (s); 758 } 759 760 /* 761 * Convert goto label names to addresses, and count a and r commands, in 762 * the given subset of the script. Free the memory used by labels in b 763 * and t commands (but not by :). 764 * 765 * TODO: Remove } nodes 766 */ 767 static void 768 fixuplabel(struct s_command *cp, struct s_command *end) 769 { 770 771 for (; cp != end; cp = cp->next) 772 switch (cp->code) { 773 case 'a': 774 case 'r': 775 appendnum++; 776 break; 777 case 'b': 778 case 't': 779 /* Resolve branch target. */ 780 if (cp->t == NULL) { 781 cp->u.c = NULL; 782 break; 783 } 784 if ((cp->u.c = findlabel(cp->t)) == NULL) 785 error(COMPILE, "undefined label '%s'", cp->t); 786 free(cp->t); 787 break; 788 case '{': 789 /* Do interior commands. */ 790 fixuplabel(cp->u.c, cp->next); 791 break; 792 } 793 } 794 795 /* 796 * Associate the given command label for later lookup. 797 */ 798 static void 799 enterlabel(struct s_command *cp) 800 { 801 struct labhash **lhp, *lh; 802 u_char *p; 803 u_int h, c; 804 805 for (h = 0, p = (u_char *)cp->t; (c = *p) != 0; p++) 806 h = (h << 5) + h + c; 807 lhp = &labels[h & LHMASK]; 808 for (lh = *lhp; lh != NULL; lh = lh->lh_next) 809 if (lh->lh_hash == h && strcmp(cp->t, lh->lh_cmd->t) == 0) 810 error(COMPILE, "duplicate label '%s'", cp->t); 811 lh = xmalloc(sizeof *lh); 812 lh->lh_next = *lhp; 813 lh->lh_hash = h; 814 lh->lh_cmd = cp; 815 lh->lh_ref = 0; 816 *lhp = lh; 817 } 818 819 /* 820 * Find the label contained in the command l in the command linked 821 * list cp. L is excluded from the search. Return NULL if not found. 822 */ 823 static struct s_command * 824 findlabel(char *name) 825 { 826 struct labhash *lh; 827 u_char *p; 828 u_int h, c; 829 830 for (h = 0, p = (u_char *)name; (c = *p) != 0; p++) 831 h = (h << 5) + h + c; 832 for (lh = labels[h & LHMASK]; lh != NULL; lh = lh->lh_next) { 833 if (lh->lh_hash == h && strcmp(name, lh->lh_cmd->t) == 0) { 834 lh->lh_ref = 1; 835 return (lh->lh_cmd); 836 } 837 } 838 return (NULL); 839 } 840 841 /* 842 * Warn about any unused labels. As a side effect, release the label hash 843 * table space. 844 */ 845 static void 846 uselabel(void) 847 { 848 struct labhash *lh, *next; 849 int i; 850 851 for (i = 0; i < LHSZ; i++) { 852 for (lh = labels[i]; lh != NULL; lh = next) { 853 next = lh->lh_next; 854 if (!lh->lh_ref) 855 warning("unused label '%s'", 856 lh->lh_cmd->t); 857 free(lh); 858 } 859 } 860 } 861