1 /* $OpenBSD: compile.c,v 1.28 2008/10/16 16:34:32 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 #ifndef lint 37 /* from: static char sccsid[] = "@(#)compile.c 8.2 (Berkeley) 4/28/95"; */ 38 static const char rcsid[] = "$OpenBSD: compile.c,v 1.28 2008/10/16 16:34:32 millert 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; /* To avoid excessive malloc calls */ 151 static size_t bufsize; 152 struct s_command *cmd, *cmd2, *stack; 153 struct s_format *fp; 154 int naddr; /* Number of addresses */ 155 156 stack = 0; 157 for (;;) { 158 if ((p = cu_fgets(&lbuf, &bufsize)) == NULL) { 159 if (stack != 0) 160 err(COMPILE, "unexpected EOF (pending }'s)"); 161 return (link); 162 } 163 164 semicolon: EATSPACE(); 165 if (*p == '#' || *p == '\0') 166 continue; 167 if (*p == ';') { 168 p++; 169 goto semicolon; 170 } 171 *link = cmd = xmalloc(sizeof(struct s_command)); 172 link = &cmd->next; 173 cmd->nonsel = cmd->inrange = 0; 174 /* First parse the addresses */ 175 naddr = 0; 176 177 /* Valid characters to start an address */ 178 #define addrchar(c) (strchr("0123456789/\\$", (c))) 179 if (addrchar(*p)) { 180 naddr++; 181 cmd->a1 = xmalloc(sizeof(struct s_addr)); 182 p = compile_addr(p, cmd->a1); 183 EATSPACE(); /* EXTENSION */ 184 if (*p == ',') { 185 p++; 186 EATSPACE(); /* EXTENSION */ 187 naddr++; 188 cmd->a2 = xmalloc(sizeof(struct s_addr)); 189 p = compile_addr(p, cmd->a2); 190 EATSPACE(); 191 } else { 192 cmd->a2 = 0; 193 } 194 } else { 195 cmd->a1 = cmd->a2 = 0; 196 } 197 198 nonsel: /* Now parse the command */ 199 if (!*p) 200 err(COMPILE, "command expected"); 201 cmd->code = *p; 202 for (fp = cmd_fmts; fp->code; fp++) 203 if (fp->code == *p) 204 break; 205 if (!fp->code) 206 err(COMPILE, "invalid command code %c", *p); 207 if (naddr > fp->naddr) 208 err(COMPILE, 209 "command %c expects up to %d address(es), found %d", 210 *p, fp->naddr, naddr); 211 switch (fp->args) { 212 case NONSEL: /* ! */ 213 p++; 214 EATSPACE(); 215 cmd->nonsel = ! cmd->nonsel; 216 goto nonsel; 217 case GROUP: /* { */ 218 p++; 219 EATSPACE(); 220 cmd->next = stack; 221 stack = cmd; 222 link = &cmd->u.c; 223 if (*p) 224 goto semicolon; 225 break; 226 case ENDGROUP: 227 /* 228 * Short-circuit command processing, since end of 229 * group is really just a noop. 230 */ 231 cmd->nonsel = 1; 232 if (stack == 0) 233 err(COMPILE, "unexpected }"); 234 cmd2 = stack; 235 stack = cmd2->next; 236 cmd2->next = cmd; 237 /*FALLTHROUGH*/ 238 case EMPTY: /* d D g G h H l n N p P q x = \0 */ 239 p++; 240 EATSPACE(); 241 if (*p == ';') { 242 p++; 243 link = &cmd->next; 244 goto semicolon; 245 } 246 if (*p) 247 err(COMPILE, 248 "extra characters at the end of %c command", cmd->code); 249 break; 250 case TEXT: /* a c i */ 251 p++; 252 EATSPACE(); 253 if (*p != '\\') 254 err(COMPILE, "command %c expects \\ followed by" 255 " text", cmd->code); 256 p++; 257 EATSPACE(); 258 if (*p) 259 err(COMPILE, "extra characters after \\ at the" 260 " end of %c command", cmd->code); 261 cmd->t = compile_text(); 262 break; 263 case COMMENT: /* \0 # */ 264 break; 265 case WFILE: /* w */ 266 p++; 267 EATSPACE(); 268 if (*p == '\0') 269 err(COMPILE, "filename expected"); 270 cmd->t = duptoeol(p, "w command", NULL); 271 if (aflag) 272 cmd->u.fd = -1; 273 else if ((cmd->u.fd = open(p, 274 O_WRONLY|O_APPEND|O_CREAT|O_TRUNC, 275 DEFFILEMODE)) == -1) 276 err(FATAL, "%s: %s", p, strerror(errno)); 277 break; 278 case RFILE: /* r */ 279 p++; 280 EATSPACE(); 281 cmd->t = duptoeol(p, "read command", NULL); 282 break; 283 case BRANCH: /* b t */ 284 p++; 285 EATSPACE(); 286 if (*p == '\0') 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 err(COMPILE, "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 err(COMPILE, "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 err(COMPILE, "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 err(COMPILE, "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 delimeter 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 err(COMPILE, "\\ can not be used as a string delimiter"); 362 else if (c == '\n') 363 err(COMPILE, "newline can not be used as a string delimiter"); 364 while (*p) { 365 if (*p == '[') { 366 if ((d = compile_ccl(&p, d)) == NULL) 367 err(COMPILE, "unbalanced brackets ([])"); 368 continue; 369 } else if (*p == '\\' && p[1] == '[') { 370 *d++ = *p++; 371 } else if (*p == '\\' && p[1] == c) { 372 p++; 373 } else if (*p == '\\' && p[1] == 'n') { 374 *d++ = '\n'; 375 p += 2; 376 continue; 377 } else if (*p == '\\' && p[1] == '\\') { 378 *d++ = *p++; 379 } else if (*p == c) { 380 *d = '\0'; 381 return (p + 1); 382 } 383 *d++ = *p++; 384 } 385 return (NULL); 386 } 387 388 389 /* compile_ccl: expand a POSIX character class */ 390 static char * 391 compile_ccl(char **sp, char *t) 392 { 393 int c, d; 394 char *s = *sp; 395 396 *t++ = *s++; 397 if (*s == '^') 398 *t++ = *s++; 399 if (*s == ']') 400 *t++ = *s++; 401 for (; *s && (*t = *s) != ']'; s++, t++) 402 if (*s == '[' && ((d = *(s+1)) == '.' || d == ':' || d == '=')) { 403 *++t = *++s, t++, s++; 404 for (c = *s; (*t = *s) != ']' || c != d; s++, t++) 405 if ((c = *s) == '\0') 406 return NULL; 407 } else if (*s == '\\' && s[1] == 'n') { 408 *t = '\n'; 409 s++; 410 } 411 if (*s == ']') { 412 *sp = ++s; 413 return (++t); 414 } else { 415 return (NULL); 416 } 417 } 418 419 /* 420 * Get a regular expression. P points to the delimiter of the regular 421 * expression; repp points to the address of a regexp pointer. Newline 422 * and delimiter escapes are processed; other escapes are ignored. 423 * Returns a pointer to the first character after the final delimiter 424 * or NULL in the case of a non terminated regular expression. The regexp 425 * pointer is set to the compiled regular expression. 426 * Cflags are passed to regcomp. 427 */ 428 static char * 429 compile_re(char *p, regex_t **repp) 430 { 431 int eval; 432 char *re; 433 434 re = xmalloc(strlen(p) + 1); /* strlen(re) <= strlen(p) */ 435 p = compile_delimited(p, re); 436 if (p && strlen(re) == 0) { 437 *repp = NULL; 438 free(re); 439 return (p); 440 } 441 *repp = xmalloc(sizeof(regex_t)); 442 if (p && (eval = regcomp(*repp, re, 0)) != 0) 443 err(COMPILE, "RE error: %s", strregerror(eval, *repp)); 444 if (maxnsub < (*repp)->re_nsub) 445 maxnsub = (*repp)->re_nsub; 446 free(re); 447 return (p); 448 } 449 450 /* 451 * Compile the substitution string of a regular expression and set res to 452 * point to a saved copy of it. Nsub is the number of parenthesized regular 453 * expressions. 454 */ 455 static char * 456 compile_subst(char *p, struct s_subst *s) 457 { 458 static char *lbuf; 459 static size_t bufsize; 460 int asize, ref, size; 461 char c, *text, *op, *sp; 462 int sawesc = 0; 463 464 c = *p++; /* Terminator character */ 465 if (c == '\0') 466 return (NULL); 467 468 s->maxbref = 0; 469 s->linenum = linenum; 470 text = NULL; 471 asize = size = 0; 472 do { 473 size_t len = ROUNDLEN(strlen(p) + 1); 474 if (asize - size < len) { 475 do { 476 asize += len; 477 } while (asize - size < len); 478 text = xrealloc(text, asize); 479 } 480 op = sp = text + size; 481 for (; *p; p++) { 482 if (*p == '\\' || sawesc) { 483 /* 484 * If this is a continuation from the last 485 * buffer, we won't have a character to 486 * skip over. 487 */ 488 if (sawesc) 489 sawesc = 0; 490 else 491 p++; 492 493 if (*p == '\0') { 494 /* 495 * This escaped character is continued 496 * in the next part of the line. Note 497 * this fact, then cause the loop to 498 * exit w/ normal EOL case and reenter 499 * above with the new buffer. 500 */ 501 sawesc = 1; 502 p--; 503 continue; 504 } else if (strchr("123456789", *p) != NULL) { 505 *sp++ = '\\'; 506 ref = *p - '0'; 507 if (s->re != NULL && 508 ref > s->re->re_nsub) 509 err(COMPILE, 510 "\\%c not defined in the RE", *p); 511 if (s->maxbref < ref) 512 s->maxbref = ref; 513 } else if (*p == '&' || *p == '\\') 514 *sp++ = '\\'; 515 } else if (*p == c) { 516 p++; 517 *sp++ = '\0'; 518 size += sp - op; 519 s->new = xrealloc(text, size); 520 return (p); 521 } else if (*p == '\n') { 522 err(COMPILE, 523 "unescaped newline inside substitute pattern"); 524 /* NOTREACHED */ 525 } 526 *sp++ = *p; 527 } 528 size += sp - op; 529 } while ((p = cu_fgets(&lbuf, &bufsize))); 530 err(COMPILE, "unterminated substitute in regular expression"); 531 /* NOTREACHED */ 532 } 533 534 /* 535 * Compile the flags of the s command 536 */ 537 static char * 538 compile_flags(char *p, struct s_subst *s) 539 { 540 int gn; /* True if we have seen g or n */ 541 long l; 542 char wfile[PATH_MAX], *q; 543 544 s->n = 1; /* Default */ 545 s->p = 0; 546 s->wfile = NULL; 547 s->wfd = -1; 548 for (gn = 0;;) { 549 EATSPACE(); /* EXTENSION */ 550 switch (*p) { 551 case 'g': 552 if (gn) 553 err(COMPILE, "more than one number or 'g' in" 554 " substitute flags"); 555 gn = 1; 556 s->n = 0; 557 break; 558 case '\0': 559 case '\n': 560 case ';': 561 return (p); 562 case 'p': 563 s->p = 1; 564 break; 565 case '1': case '2': case '3': 566 case '4': case '5': case '6': 567 case '7': case '8': case '9': 568 if (gn) 569 err(COMPILE, "more than one number or 'g' in" 570 " substitute flags"); 571 gn = 1; 572 l = strtol(p, &p, 10); 573 if (l <= 0 || l >= INT_MAX) 574 err(COMPILE, 575 "number in substitute flags out of range"); 576 s->n = (int)l; 577 continue; 578 case 'w': 579 p++; 580 #ifdef HISTORIC_PRACTICE 581 if (*p != ' ') { 582 err(WARNING, "space missing before w wfile"); 583 return (p); 584 } 585 #endif 586 EATSPACE(); 587 q = wfile; 588 while (*p) { 589 if (*p == '\n') 590 break; 591 *q++ = *p++; 592 } 593 *q = '\0'; 594 if (q == wfile) 595 err(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 err(FATAL, "%s: %s", wfile, strerror(errno)); 601 return (p); 602 default: 603 err(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 err(COMPILE, 623 "transform pattern can not be delimited by newline or backslash"); 624 old = xmalloc(strlen(p) + 1); 625 p = compile_delimited(p, old); 626 if (p == NULL) { 627 err(COMPILE, "unterminated transform source string"); 628 goto bad; 629 } 630 new = xmalloc(strlen(p) + 1); 631 p = compile_delimited(--p, new); 632 if (p == NULL) { 633 err(COMPILE, "unterminated transform target string"); 634 goto bad; 635 } 636 EATSPACE(); 637 if (strlen(new) != strlen(old)) { 638 err(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 EATSPACE(); 679 for (esc_nl = 0; *p != '\0'; p++) { 680 if (*p == '\\' && p[1] != '\0' && *++p == '\n') 681 esc_nl = 1; 682 *s++ = *p; 683 } 684 size += s - op; 685 if (!esc_nl) { 686 *s = '\0'; 687 break; 688 } 689 } 690 free(lbuf); 691 text[size] = '\0'; 692 return (xrealloc(text, size + 1)); 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 err(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 err(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(*s); 745 } else { 746 for (start = s; *s != '\0' && *s != '\n'; ++s) 747 ws = isspace(*s); 748 *s = '\0'; 749 } 750 if (ws) 751 err(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 err(COMPILE2, "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 err(COMPILE2, "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 err(WARNING, "unused label '%s'", 856 lh->lh_cmd->t); 857 free(lh); 858 } 859 } 860 } 861