1 /* $OpenBSD: compile.c,v 1.42 2017/08/01 18:05:53 martijn 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 pledge_wpath = 1; 270 } 271 else if ((cmd->u.fd = open(p, 272 O_WRONLY|O_APPEND|O_CREAT|O_TRUNC, 273 DEFFILEMODE)) == -1) 274 error(FATAL, "%s: %s", p, strerror(errno)); 275 break; 276 case RFILE: /* r */ 277 pledge_rpath = 1; 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 error(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 error(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 error(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 error(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, int is_tr) 353 { 354 char c; 355 356 c = *p++; 357 if (c == '\0') 358 return (NULL); 359 else if (c == '\\') 360 error(COMPILE, "\\ can not be used as a string delimiter"); 361 else if (c == '\n') 362 error(COMPILE, "newline can not be used as a string delimiter"); 363 while (*p) { 364 if (*p == '[' && *p != c) { 365 if ((d = compile_ccl(&p, d)) == NULL) 366 error(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 if (is_tr) 378 p++; 379 else 380 *d++ = *p++; 381 } else if (*p == c) { 382 *d = '\0'; 383 return (p + 1); 384 } 385 *d++ = *p++; 386 } 387 return (NULL); 388 } 389 390 391 /* compile_ccl: expand a POSIX character class */ 392 static char * 393 compile_ccl(char **sp, char *t) 394 { 395 int c, d; 396 char *s = *sp; 397 398 *t++ = *s++; 399 if (*s == '^') 400 *t++ = *s++; 401 if (*s == ']') 402 *t++ = *s++; 403 for (; *s && (*t = *s) != ']'; s++, t++) 404 if (*s == '[' && ((d = *(s+1)) == '.' || d == ':' || d == '=')) { 405 *++t = *++s, t++, s++; 406 for (c = *s; (*t = *s) != ']' || c != d; s++, t++) 407 if ((c = *s) == '\0') 408 return NULL; 409 } else if (*s == '\\' && s[1] == 'n') { 410 *t = '\n'; 411 s++; 412 } 413 if (*s == ']') { 414 *sp = ++s; 415 return (++t); 416 } else { 417 return (NULL); 418 } 419 } 420 421 /* 422 * Get a regular expression. P points to the delimiter of the regular 423 * expression; repp points to the address of a regexp pointer. Newline 424 * and delimiter escapes are processed; other escapes are ignored. 425 * Returns a pointer to the first character after the final delimiter 426 * or NULL in the case of a non terminated regular expression. The regexp 427 * pointer is set to the compiled regular expression. 428 * Cflags are passed to regcomp. 429 */ 430 static char * 431 compile_re(char *p, regex_t **repp) 432 { 433 int eval; 434 char *re; 435 436 re = xmalloc(strlen(p) + 1); /* strlen(re) <= strlen(p) */ 437 p = compile_delimited(p, re, 0); 438 if (p && strlen(re) == 0) { 439 *repp = NULL; 440 free(re); 441 return (p); 442 } 443 *repp = xmalloc(sizeof(regex_t)); 444 if (p && (eval = regcomp(*repp, re, Eflag ? REG_EXTENDED : 0)) != 0) 445 error(COMPILE, "RE error: %s", strregerror(eval, *repp)); 446 if (maxnsub < (*repp)->re_nsub) 447 maxnsub = (*repp)->re_nsub; 448 free(re); 449 return (p); 450 } 451 452 /* 453 * Compile the substitution string of a regular expression and set res to 454 * point to a saved copy of it. Nsub is the number of parenthesized regular 455 * expressions. 456 */ 457 static char * 458 compile_subst(char *p, struct s_subst *s) 459 { 460 static char *lbuf; 461 static size_t bufsize; 462 int asize, ref, size; 463 char c, *text, *op, *sp; 464 int sawesc = 0; 465 466 c = *p++; /* Terminator character */ 467 if (c == '\0') 468 return (NULL); 469 470 s->maxbref = 0; 471 s->linenum = linenum; 472 text = NULL; 473 asize = size = 0; 474 do { 475 size_t len = ROUNDLEN(strlen(p) + 1); 476 if (asize - size < len) { 477 do { 478 asize += len; 479 } while (asize - size < len); 480 text = xrealloc(text, asize); 481 } 482 op = sp = text + size; 483 for (; *p; p++) { 484 if (*p == '\\' || sawesc) { 485 /* 486 * If this is a continuation from the last 487 * buffer, we won't have a character to 488 * skip over. 489 */ 490 if (sawesc) 491 sawesc = 0; 492 else 493 p++; 494 495 if (*p == '\0') { 496 /* 497 * This escaped character is continued 498 * in the next part of the line. Note 499 * this fact, then cause the loop to 500 * exit w/ normal EOL case and reenter 501 * above with the new buffer. 502 */ 503 sawesc = 1; 504 p--; 505 continue; 506 } else if (strchr("123456789", *p) != NULL) { 507 *sp++ = '\\'; 508 ref = *p - '0'; 509 if (s->re != NULL && 510 ref > s->re->re_nsub) 511 error(COMPILE, 512 "\\%c not defined in the RE", *p); 513 if (s->maxbref < ref) 514 s->maxbref = ref; 515 } else if (*p == '&' || *p == '\\') 516 *sp++ = '\\'; 517 } else if (*p == c) { 518 p++; 519 *sp++ = '\0'; 520 size += sp - op; 521 s->new = xrealloc(text, size); 522 return (p); 523 } else if (*p == '\n') { 524 error(COMPILE, 525 "unescaped newline inside substitute pattern"); 526 } 527 *sp++ = *p; 528 } 529 size += sp - op; 530 } while ((p = cu_fgets(&lbuf, &bufsize))); 531 error(COMPILE, "unterminated substitute in regular expression"); 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, *eq; 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 error(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 error(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 error(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 warning("space missing before w wfile"); 583 return (p); 584 } 585 #endif 586 EATSPACE(); 587 q = wfile; 588 eq = wfile + sizeof(wfile) - 1; 589 while (*p) { 590 if (*p == '\n') 591 break; 592 if (q >= eq) 593 error(COMPILE, "wfile too long"); 594 *q++ = *p++; 595 } 596 *q = '\0'; 597 if (q == wfile) 598 error(COMPILE, "no wfile specified"); 599 s->wfile = strdup(wfile); 600 if (aflag) 601 pledge_wpath = 1; 602 else if ((s->wfd = open(wfile, 603 O_WRONLY|O_APPEND|O_CREAT|O_TRUNC, 604 DEFFILEMODE)) == -1) 605 error(FATAL, "%s: %s", wfile, strerror(errno)); 606 return (p); 607 default: 608 error(COMPILE, 609 "bad flag in substitute command: '%c'", *p); 610 break; 611 } 612 p++; 613 } 614 } 615 616 /* 617 * Compile a translation set of strings into a lookup table. 618 */ 619 static char * 620 compile_tr(char *p, char **transtab) 621 { 622 int i; 623 char *lt, *op, *np; 624 char *old = NULL, *new = NULL; 625 626 if (*p == '\0' || *p == '\\') 627 error(COMPILE, 628 "transform pattern can not be delimited by newline or backslash"); 629 old = xmalloc(strlen(p) + 1); 630 p = compile_delimited(p, old, 1); 631 if (p == NULL) { 632 error(COMPILE, "unterminated transform source string"); 633 goto bad; 634 } 635 new = xmalloc(strlen(p) + 1); 636 p = compile_delimited(--p, new, 1); 637 if (p == NULL) { 638 error(COMPILE, "unterminated transform target string"); 639 goto bad; 640 } 641 EATSPACE(); 642 if (strlen(new) != strlen(old)) { 643 error(COMPILE, "transform strings are not the same length"); 644 goto bad; 645 } 646 /* We assume characters are 8 bits */ 647 lt = xmalloc(UCHAR_MAX + 1); 648 for (i = 0; i <= UCHAR_MAX; i++) 649 lt[i] = (char)i; 650 for (op = old, np = new; *op; op++, np++) 651 lt[(u_char)*op] = *np; 652 *transtab = lt; 653 free(old); 654 free(new); 655 return (p); 656 bad: 657 free(old); 658 free(new); 659 return (NULL); 660 } 661 662 /* 663 * Compile the text following an a, c, or i command. 664 */ 665 static char * 666 compile_text(void) 667 { 668 int asize, esc_nl, size; 669 char *lbuf, *text, *p, *op, *s; 670 size_t bufsize; 671 672 lbuf = text = NULL; 673 asize = size = 0; 674 while ((p = cu_fgets(&lbuf, &bufsize))) { 675 size_t len = ROUNDLEN(strlen(p) + 1); 676 if (asize - size < len) { 677 do { 678 asize += len; 679 } while (asize - size < len); 680 text = xrealloc(text, asize); 681 } 682 op = s = text + size; 683 for (esc_nl = 0; *p != '\0'; p++) { 684 if (*p == '\\' && p[1] != '\0' && *++p == '\n') 685 esc_nl = 1; 686 *s++ = *p; 687 } 688 size += s - op; 689 if (!esc_nl) { 690 *s = '\0'; 691 break; 692 } 693 } 694 free(lbuf); 695 text = xrealloc(text, size + 1); 696 text[size] = '\0'; 697 return (text); 698 } 699 700 /* 701 * Get an address and return a pointer to the first character after 702 * it. Fill the structure pointed to according to the address. 703 */ 704 static char * 705 compile_addr(char *p, struct s_addr *a) 706 { 707 char *end; 708 709 switch (*p) { 710 case '\\': /* Context address */ 711 ++p; 712 /* FALLTHROUGH */ 713 case '/': /* Context address */ 714 p = compile_re(p, &a->u.r); 715 if (p == NULL) 716 error(COMPILE, "unterminated regular expression"); 717 a->type = AT_RE; 718 return (p); 719 720 case '$': /* Last line */ 721 a->type = AT_LAST; 722 return (p + 1); 723 /* Line number */ 724 case '0': case '1': case '2': case '3': case '4': 725 case '5': case '6': case '7': case '8': case '9': 726 a->type = AT_LINE; 727 a->u.l = strtoul(p, &end, 10); 728 return (end); 729 default: 730 error(COMPILE, "expected context address"); 731 return (NULL); 732 } 733 } 734 735 /* 736 * duptoeol -- 737 * Return a copy of all the characters up to \n or \0. 738 */ 739 static char * 740 duptoeol(char *s, char *ctype, char **semi) 741 { 742 size_t len; 743 int ws; 744 char *start; 745 746 ws = 0; 747 if (semi) { 748 for (start = s; *s != '\0' && *s != '\n' && *s != ';'; ++s) 749 ws = isspace((unsigned char)*s); 750 } else { 751 for (start = s; *s != '\0' && *s != '\n'; ++s) 752 ws = isspace((unsigned char)*s); 753 *s = '\0'; 754 } 755 if (ws) 756 warning("whitespace after %s", ctype); 757 len = s - start + 1; 758 if (semi) 759 *semi = s; 760 s = xmalloc(len); 761 strlcpy(s, start, len); 762 return (s); 763 } 764 765 /* 766 * Convert goto label names to addresses, and count a and r commands, in 767 * the given subset of the script. Free the memory used by labels in b 768 * and t commands (but not by :). 769 * 770 * TODO: Remove } nodes 771 */ 772 static void 773 fixuplabel(struct s_command *cp, struct s_command *end) 774 { 775 776 for (; cp != end; cp = cp->next) 777 switch (cp->code) { 778 case 'a': 779 case 'r': 780 appendnum++; 781 break; 782 case 'b': 783 case 't': 784 /* Resolve branch target. */ 785 if (cp->t == NULL) { 786 cp->u.c = NULL; 787 break; 788 } 789 if ((cp->u.c = findlabel(cp->t)) == NULL) 790 error(COMPILE, "undefined label '%s'", cp->t); 791 free(cp->t); 792 break; 793 case '{': 794 /* Do interior commands. */ 795 fixuplabel(cp->u.c, cp->next); 796 break; 797 } 798 } 799 800 /* 801 * Associate the given command label for later lookup. 802 */ 803 static void 804 enterlabel(struct s_command *cp) 805 { 806 struct labhash **lhp, *lh; 807 u_char *p; 808 u_int h, c; 809 810 for (h = 0, p = (u_char *)cp->t; (c = *p) != 0; p++) 811 h = (h << 5) + h + c; 812 lhp = &labels[h & LHMASK]; 813 for (lh = *lhp; lh != NULL; lh = lh->lh_next) 814 if (lh->lh_hash == h && strcmp(cp->t, lh->lh_cmd->t) == 0) 815 error(COMPILE, "duplicate label '%s'", cp->t); 816 lh = xmalloc(sizeof *lh); 817 lh->lh_next = *lhp; 818 lh->lh_hash = h; 819 lh->lh_cmd = cp; 820 lh->lh_ref = 0; 821 *lhp = lh; 822 } 823 824 /* 825 * Find the label contained in the command l in the command linked 826 * list cp. L is excluded from the search. Return NULL if not found. 827 */ 828 static struct s_command * 829 findlabel(char *name) 830 { 831 struct labhash *lh; 832 u_char *p; 833 u_int h, c; 834 835 for (h = 0, p = (u_char *)name; (c = *p) != 0; p++) 836 h = (h << 5) + h + c; 837 for (lh = labels[h & LHMASK]; lh != NULL; lh = lh->lh_next) { 838 if (lh->lh_hash == h && strcmp(name, lh->lh_cmd->t) == 0) { 839 lh->lh_ref = 1; 840 return (lh->lh_cmd); 841 } 842 } 843 return (NULL); 844 } 845 846 /* 847 * Warn about any unused labels. As a side effect, release the label hash 848 * table space. 849 */ 850 static void 851 uselabel(void) 852 { 853 struct labhash *lh, *next; 854 int i; 855 856 for (i = 0; i < LHSZ; i++) { 857 for (lh = labels[i]; lh != NULL; lh = next) { 858 next = lh->lh_next; 859 if (!lh->lh_ref) 860 warning("unused label '%s'", 861 lh->lh_cmd->t); 862 free(lh); 863 } 864 } 865 } 866