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1.1 deraadt 1: /*-
2: * Copyright (c) 1992 Diomidis Spinellis.
3: * Copyright (c) 1992, 1993
4: * The Regents of the University of California. All rights reserved.
5: *
6: * This code is derived from software contributed to Berkeley by
7: * Diomidis Spinellis of Imperial College, University of London.
8: *
9: * Redistribution and use in source and binary forms, with or without
10: * modification, are permitted provided that the following conditions
11: * are met:
12: * 1. Redistributions of source code must retain the above copyright
13: * notice, this list of conditions and the following disclaimer.
14: * 2. Redistributions in binary form must reproduce the above copyright
15: * notice, this list of conditions and the following disclaimer in the
16: * documentation and/or other materials provided with the distribution.
17: * 3. All advertising materials mentioning features or use of this software
18: * must display the following acknowledgement:
19: * This product includes software developed by the University of
20: * California, Berkeley and its contributors.
21: * 4. Neither the name of the University nor the names of its contributors
22: * may be used to endorse or promote products derived from this software
23: * without specific prior written permission.
24: *
25: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
26: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
29: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35: * SUCH DAMAGE.
36: */
37:
38: #ifndef lint
39: /* from: static char sccsid[] = "@(#)compile.c 8.1 (Berkeley) 6/6/93"; */
40: static char *rcsid = "$Id: compile.c,v 1.14 1995/03/09 11:19:24 mycroft Exp $";
41: #endif /* not lint */
42:
43: #include <sys/types.h>
44: #include <sys/stat.h>
45:
46: #include <ctype.h>
47: #include <errno.h>
48: #include <fcntl.h>
49: #include <limits.h>
50: #include <regex.h>
51: #include <stdio.h>
52: #include <stdlib.h>
53: #include <string.h>
54:
55: #include "defs.h"
56: #include "extern.h"
57:
58: #define LHSZ 128
59: #define LHMASK (LHSZ - 1)
60: static struct labhash {
61: struct labhash *lh_next;
62: u_int lh_hash;
63: struct s_command *lh_cmd;
64: int lh_ref;
65: } *labels[LHSZ];
66:
67: static char *compile_addr __P((char *, struct s_addr *));
68: static char *compile_ccl __P((char **, char *));
69: static char *compile_delimited __P((char *, char *));
70: static char *compile_flags __P((char *, struct s_subst *));
71: static char *compile_re __P((char *, regex_t **));
72: static char *compile_subst __P((char *, struct s_subst *));
73: static char *compile_text __P((void));
74: static char *compile_tr __P((char *, char **));
75: static struct s_command
76: **compile_stream __P((struct s_command **));
77: static char *duptoeol __P((char *, char *));
78: static void enterlabel __P((struct s_command *));
79: static struct s_command
80: *findlabel __P((char *));
81: static void fixuplabel __P((struct s_command *, struct s_command *));
82: static void uselabel __P((void));
83:
84: /*
85: * Command specification. This is used to drive the command parser.
86: */
87: struct s_format {
88: char code; /* Command code */
89: int naddr; /* Number of address args */
90: enum e_args args; /* Argument type */
91: };
92:
93: static struct s_format cmd_fmts[] = {
94: {'{', 2, GROUP},
95: {'}', 0, ENDGROUP},
96: {'a', 1, TEXT},
97: {'b', 2, BRANCH},
98: {'c', 2, TEXT},
99: {'d', 2, EMPTY},
100: {'D', 2, EMPTY},
101: {'g', 2, EMPTY},
102: {'G', 2, EMPTY},
103: {'h', 2, EMPTY},
104: {'H', 2, EMPTY},
105: {'i', 1, TEXT},
106: {'l', 2, EMPTY},
107: {'n', 2, EMPTY},
108: {'N', 2, EMPTY},
109: {'p', 2, EMPTY},
110: {'P', 2, EMPTY},
111: {'q', 1, EMPTY},
112: {'r', 1, RFILE},
113: {'s', 2, SUBST},
114: {'t', 2, BRANCH},
115: {'w', 2, WFILE},
116: {'x', 2, EMPTY},
117: {'y', 2, TR},
118: {'!', 2, NONSEL},
119: {':', 0, LABEL},
120: {'#', 0, COMMENT},
121: {'=', 1, EMPTY},
122: {'\0', 0, COMMENT},
123: };
124:
125: /* The compiled program. */
126: struct s_command *prog;
127:
128: /*
129: * Compile the program into prog.
130: * Initialise appends.
131: */
132: void
133: compile()
134: {
135: *compile_stream(&prog) = NULL;
136: fixuplabel(prog, NULL);
137: uselabel();
138: appends = xmalloc(sizeof(struct s_appends) * appendnum);
139: match = xmalloc((maxnsub + 1) * sizeof(regmatch_t));
140: }
141:
142: #define EATSPACE() do { \
143: if (p) \
144: while (*p && isascii(*p) && isspace(*p)) \
145: p++; \
146: } while (0)
147:
148: static struct s_command **
149: compile_stream(link)
150: struct s_command **link;
151: {
152: register char *p;
153: static char lbuf[_POSIX2_LINE_MAX + 1]; /* To save stack */
154: struct s_command *cmd, *cmd2, *stack;
155: struct s_format *fp;
156: int naddr; /* Number of addresses */
157:
158: stack = 0;
159: for (;;) {
160: if ((p = cu_fgets(lbuf, sizeof(lbuf))) == NULL) {
161: if (stack != 0)
162: err(COMPILE, "unexpected EOF (pending }'s)");
163: return (link);
164: }
165:
166: semicolon: EATSPACE();
167: if (p && (*p == '#' || *p == '\0'))
168: continue;
169: *link = cmd = xmalloc(sizeof(struct s_command));
170: link = &cmd->next;
171: cmd->nonsel = cmd->inrange = 0;
172: /* First parse the addresses */
173: naddr = 0;
174:
175: /* Valid characters to start an address */
176: #define addrchar(c) (strchr("0123456789/\\$", (c)))
177: if (addrchar(*p)) {
178: naddr++;
179: cmd->a1 = xmalloc(sizeof(struct s_addr));
180: p = compile_addr(p, cmd->a1);
181: EATSPACE(); /* EXTENSION */
182: if (*p == ',') {
183: p++;
184: EATSPACE(); /* EXTENSION */
185: naddr++;
186: cmd->a2 = xmalloc(sizeof(struct s_addr));
187: p = compile_addr(p, cmd->a2);
188: EATSPACE();
189: } else
190: cmd->a2 = 0;
191: } else
192: cmd->a1 = cmd->a2 = 0;
193:
194: nonsel: /* Now parse the command */
195: if (!*p)
196: err(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: err(COMPILE, "invalid command code %c", *p);
203: if (naddr > fp->naddr)
204: err(COMPILE,
205: "command %c expects up to %d address(es), found %d", *p, fp->naddr, naddr);
206: switch (fp->args) {
207: case NONSEL: /* ! */
208: p++;
209: EATSPACE();
210: cmd->nonsel = ! cmd->nonsel;
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: err(COMPILE, "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: err(COMPILE,
243: "extra characters at the end of %c command", cmd->code);
244: break;
245: case TEXT: /* a c i */
246: p++;
247: EATSPACE();
248: if (*p != '\\')
249: err(COMPILE,
250: "command %c expects \\ followed by text", cmd->code);
251: p++;
252: EATSPACE();
253: if (*p)
254: err(COMPILE,
255: "extra characters after \\ at the 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: err(COMPILE, "filename expected");
265: cmd->t = duptoeol(p, "w command");
266: if (aflag)
267: cmd->u.fd = -1;
268: else if ((cmd->u.fd = open(p,
269: O_WRONLY|O_APPEND|O_CREAT|O_TRUNC,
270: DEFFILEMODE)) == -1)
271: err(FATAL, "%s: %s\n", p, strerror(errno));
272: break;
273: case RFILE: /* r */
274: p++;
275: EATSPACE();
276: if (*p == '\0')
277: err(COMPILE, "filename expected");
278: else
279: cmd->t = duptoeol(p, "read command");
280: break;
281: case BRANCH: /* b t */
282: p++;
283: EATSPACE();
284: if (*p == '\0')
285: cmd->t = NULL;
286: else
287: cmd->t = duptoeol(p, "branch");
288: break;
289: case LABEL: /* : */
290: p++;
291: EATSPACE();
292: cmd->t = duptoeol(p, "label");
293: if (strlen(p) == 0)
294: err(COMPILE, "empty label");
295: enterlabel(cmd);
296: break;
297: case SUBST: /* s */
298: p++;
299: if (*p == '\0' || *p == '\\')
300: err(COMPILE,
301: "substitute pattern can not be delimited by newline or backslash");
302: cmd->u.s = xmalloc(sizeof(struct s_subst));
303: p = compile_re(p, &cmd->u.s->re);
304: if (p == NULL)
305: err(COMPILE, "unterminated substitute pattern");
306: --p;
307: p = compile_subst(p, cmd->u.s);
308: p = compile_flags(p, cmd->u.s);
309: EATSPACE();
310: if (*p == ';') {
311: p++;
312: link = &cmd->next;
313: goto semicolon;
314: }
315: break;
316: case TR: /* y */
317: p++;
318: p = compile_tr(p, (char **)&cmd->u.y);
319: EATSPACE();
320: if (*p == ';') {
321: p++;
322: link = &cmd->next;
323: goto semicolon;
324: }
325: if (*p)
326: err(COMPILE,
327: "extra text at the end of a transform command");
328: break;
329: }
330: }
331: }
332:
333: /*
334: * Get a delimited string. P points to the delimeter of the string; d points
335: * to a buffer area. Newline and delimiter escapes are processed; other
336: * escapes are ignored.
337: *
338: * Returns a pointer to the first character after the final delimiter or NULL
339: * in the case of a non-terminated string. The character array d is filled
340: * with the processed string.
341: */
342: static char *
343: compile_delimited(p, d)
344: char *p, *d;
345: {
346: char c;
347:
348: c = *p++;
349: if (c == '\0')
350: return (NULL);
351: else if (c == '\\')
352: err(COMPILE, "\\ can not be used as a string delimiter");
353: else if (c == '\n')
354: err(COMPILE, "newline can not be used as a string delimiter");
355: while (*p) {
356: if (*p == '[') {
357: if ((d = compile_ccl(&p, d)) == NULL)
358: err(COMPILE, "unbalanced brackets ([])");
359: continue;
360: } else if (*p == '\\' && p[1] == '[') {
361: *d++ = *p++;
362: } else if (*p == '\\' && p[1] == c)
363: p++;
364: else if (*p == '\\' && p[1] == 'n') {
365: *d++ = '\n';
366: p += 2;
367: continue;
368: } else if (*p == '\\' && p[1] == '\\')
369: *d++ = *p++;
370: else if (*p == c) {
371: *d = '\0';
372: return (p + 1);
373: }
374: *d++ = *p++;
375: }
376: return (NULL);
377: }
378:
379:
380: /* compile_ccl: expand a POSIX character class */
381: static char *
382: compile_ccl(sp, t)
383: char **sp;
384: char *t;
385: {
386: int c, d;
387: char *s = *sp;
388:
389: *t++ = *s++;
390: if (*s == '^')
391: *t++ = *s++;
392: if (*s == ']')
393: *t++ = *s++;
394: for (; *s && (*t = *s) != ']'; s++, t++)
395: if (*s == '[' && ((d = *(s+1)) == '.' || d == ':' || d == '=')) {
396: *++t = *++s, t++, s++;
397: for (c = *s; (*t = *s) != ']' || c != d; s++, t++)
398: if ((c = *s) == '\0')
399: return NULL;
400: } else if (*s == '\\' && s[1] == 'n')
401: *t = '\n', s++;
402: return (*s == ']') ? *sp = ++s, ++t : NULL;
403: }
404:
405: /*
406: * Get a regular expression. P points to the delimiter of the regular
407: * expression; repp points to the address of a regexp pointer. Newline
408: * and delimiter escapes are processed; other escapes are ignored.
409: * Returns a pointer to the first character after the final delimiter
410: * or NULL in the case of a non terminated regular expression. The regexp
411: * pointer is set to the compiled regular expression.
412: * Cflags are passed to regcomp.
413: */
414: static char *
415: compile_re(p, repp)
416: char *p;
417: regex_t **repp;
418: {
419: int eval;
420: char re[_POSIX2_LINE_MAX + 1];
421:
422: p = compile_delimited(p, re);
423: if (p && strlen(re) == 0) {
424: *repp = NULL;
425: return (p);
426: }
427: *repp = xmalloc(sizeof(regex_t));
428: if (p && (eval = regcomp(*repp, re, 0)) != 0)
429: err(COMPILE, "RE error: %s", strregerror(eval, *repp));
430: if (maxnsub < (*repp)->re_nsub)
431: maxnsub = (*repp)->re_nsub;
432: return (p);
433: }
434:
435: /*
436: * Compile the substitution string of a regular expression and set res to
437: * point to a saved copy of it. Nsub is the number of parenthesized regular
438: * expressions.
439: */
440: static char *
441: compile_subst(p, s)
442: char *p;
443: struct s_subst *s;
444: {
445: static char lbuf[_POSIX2_LINE_MAX + 1];
446: int asize, ref, size;
447: char c, *text, *op, *sp;
448:
449: c = *p++; /* Terminator character */
450: if (c == '\0')
451: return (NULL);
452:
453: s->maxbref = 0;
454: s->linenum = linenum;
455: asize = 2 * _POSIX2_LINE_MAX + 1;
456: text = xmalloc(asize);
457: size = 0;
458: do {
459: op = sp = text + size;
460: for (; *p; p++) {
461: if (*p == '\\') {
462: p++;
463: if (strchr("123456789", *p) != NULL) {
464: *sp++ = '\\';
465: ref = *p - '0';
466: if (s->re != NULL &&
467: ref > s->re->re_nsub)
468: err(COMPILE,
469: "\\%c not defined in the RE", *p);
470: if (s->maxbref < ref)
471: s->maxbref = ref;
472: } else if (*p == '&' || *p == '\\')
473: *sp++ = '\\';
474: } else if (*p == c) {
475: p++;
476: *sp++ = '\0';
477: size += sp - op;
478: s->new = xrealloc(text, size);
479: return (p);
480: } else if (*p == '\n') {
481: err(COMPILE,
482: "unescaped newline inside substitute pattern");
483: /* NOTREACHED */
484: }
485: *sp++ = *p;
486: }
487: size += sp - op;
488: if (asize - size < _POSIX2_LINE_MAX + 1) {
489: asize *= 2;
490: text = xmalloc(asize);
491: }
492: } while (cu_fgets(p = lbuf, sizeof(lbuf)));
493: err(COMPILE, "unterminated substitute in regular expression");
494: /* NOTREACHED */
495: }
496:
497: /*
498: * Compile the flags of the s command
499: */
500: static char *
501: compile_flags(p, s)
502: char *p;
503: struct s_subst *s;
504: {
505: int gn; /* True if we have seen g or n */
506: char wfile[_POSIX2_LINE_MAX + 1], *q;
507:
508: s->n = 1; /* Default */
509: s->p = 0;
510: s->wfile = NULL;
511: s->wfd = -1;
512: for (gn = 0;;) {
513: EATSPACE(); /* EXTENSION */
514: switch (*p) {
515: case 'g':
516: if (gn)
517: err(COMPILE,
518: "more than one number or 'g' in substitute flags");
519: gn = 1;
520: s->n = 0;
521: break;
522: case '\0':
523: case '\n':
524: case ';':
525: return (p);
526: case 'p':
527: s->p = 1;
528: break;
529: case '1': case '2': case '3':
530: case '4': case '5': case '6':
531: case '7': case '8': case '9':
532: if (gn)
533: err(COMPILE,
534: "more than one number or 'g' in substitute flags");
535: gn = 1;
536: /* XXX Check for overflow */
537: s->n = (int)strtol(p, &p, 10);
538: break;
539: case 'w':
540: p++;
541: #ifdef HISTORIC_PRACTICE
542: if (*p != ' ') {
543: err(WARNING, "space missing before w wfile");
544: return (p);
545: }
546: #endif
547: EATSPACE();
548: q = wfile;
549: while (*p) {
550: if (*p == '\n')
551: break;
552: *q++ = *p++;
553: }
554: *q = '\0';
555: if (q == wfile)
556: err(COMPILE, "no wfile specified");
557: s->wfile = strdup(wfile);
558: if (!aflag && (s->wfd = open(wfile,
559: O_WRONLY|O_APPEND|O_CREAT|O_TRUNC,
560: DEFFILEMODE)) == -1)
561: err(FATAL, "%s: %s\n", wfile, strerror(errno));
562: return (p);
563: default:
564: err(COMPILE,
565: "bad flag in substitute command: '%c'", *p);
566: break;
567: }
568: p++;
569: }
570: }
571:
572: /*
573: * Compile a translation set of strings into a lookup table.
574: */
575: static char *
576: compile_tr(p, transtab)
577: char *p;
578: char **transtab;
579: {
580: int i;
581: char *lt, *op, *np;
582: char old[_POSIX2_LINE_MAX + 1];
583: char new[_POSIX2_LINE_MAX + 1];
584:
585: if (*p == '\0' || *p == '\\')
586: err(COMPILE,
587: "transform pattern can not be delimited by newline or backslash");
588: p = compile_delimited(p, old);
589: if (p == NULL) {
590: err(COMPILE, "unterminated transform source string");
591: return (NULL);
592: }
593: p = compile_delimited(--p, new);
594: if (p == NULL) {
595: err(COMPILE, "unterminated transform target string");
596: return (NULL);
597: }
598: EATSPACE();
599: if (strlen(new) != strlen(old)) {
600: err(COMPILE, "transform strings are not the same length");
601: return (NULL);
602: }
603: /* We assume characters are 8 bits */
604: lt = xmalloc(UCHAR_MAX);
605: for (i = 0; i <= UCHAR_MAX; i++)
606: lt[i] = (char)i;
607: for (op = old, np = new; *op; op++, np++)
608: lt[(u_char)*op] = *np;
609: *transtab = lt;
610: return (p);
611: }
612:
613: /*
614: * Compile the text following an a or i command.
615: */
616: static char *
617: compile_text()
618: {
619: int asize, size;
620: char *text, *p, *op, *s;
621: char lbuf[_POSIX2_LINE_MAX + 1];
622:
623: asize = 2 * _POSIX2_LINE_MAX + 1;
624: text = xmalloc(asize);
625: size = 0;
626: while (cu_fgets(lbuf, sizeof(lbuf))) {
627: op = s = text + size;
628: p = lbuf;
629: EATSPACE();
630: for (; *p; p++) {
631: if (*p == '\\')
632: p++;
633: *s++ = *p;
634: }
635: size += s - op;
636: if (p[-2] != '\\') {
637: *s = '\0';
638: break;
639: }
640: if (asize - size < _POSIX2_LINE_MAX + 1) {
641: asize *= 2;
642: text = xmalloc(asize);
643: }
644: }
645: return (xrealloc(text, size + 1));
646: }
647:
648: /*
649: * Get an address and return a pointer to the first character after
650: * it. Fill the structure pointed to according to the address.
651: */
652: static char *
653: compile_addr(p, a)
654: char *p;
655: struct s_addr *a;
656: {
657: char *end;
658:
659: switch (*p) {
660: case '\\': /* Context address */
661: ++p;
662: /* FALLTHROUGH */
663: case '/': /* Context address */
664: p = compile_re(p, &a->u.r);
665: if (p == NULL)
666: err(COMPILE, "unterminated regular expression");
667: a->type = AT_RE;
668: return (p);
669:
670: case '$': /* Last line */
671: a->type = AT_LAST;
672: return (p + 1);
673: /* Line number */
674: case '0': case '1': case '2': case '3': case '4':
675: case '5': case '6': case '7': case '8': case '9':
676: a->type = AT_LINE;
677: a->u.l = strtol(p, &end, 10);
678: return (end);
679: default:
680: err(COMPILE, "expected context address");
681: return (NULL);
682: }
683: }
684:
685: /*
686: * duptoeol --
687: * Return a copy of all the characters up to \n or \0.
688: */
689: static char *
690: duptoeol(s, ctype)
691: register char *s;
692: char *ctype;
693: {
694: size_t len;
695: int ws;
696: char *start;
697:
698: ws = 0;
699: for (start = s; *s != '\0' && *s != '\n'; ++s)
700: ws = isspace(*s);
701: *s = '\0';
702: if (ws)
703: err(WARNING, "whitespace after %s", ctype);
704: len = s - start + 1;
705: return (memmove(xmalloc(len), start, len));
706: }
707:
708: /*
709: * Convert goto label names to addresses, and count a and r commands, in
710: * the given subset of the script. Free the memory used by labels in b
711: * and t commands (but not by :).
712: *
713: * TODO: Remove } nodes
714: */
715: static void
716: fixuplabel(cp, end)
717: struct s_command *cp, *end;
718: {
719:
720: for (; cp != end; cp = cp->next)
721: switch (cp->code) {
722: case 'a':
723: case 'r':
724: appendnum++;
725: break;
726: case 'b':
727: case 't':
728: /* Resolve branch target. */
729: if (cp->t == NULL) {
730: cp->u.c = NULL;
731: break;
732: }
733: if ((cp->u.c = findlabel(cp->t)) == NULL)
734: err(COMPILE2, "undefined label '%s'", cp->t);
735: free(cp->t);
736: break;
737: case '{':
738: /* Do interior commands. */
739: fixuplabel(cp->u.c, cp->next);
740: break;
741: }
742: }
743:
744: /*
745: * Associate the given command label for later lookup.
746: */
747: static void
748: enterlabel(cp)
749: struct s_command *cp;
750: {
751: register struct labhash **lhp, *lh;
752: register u_char *p;
753: register u_int h, c;
754:
755: for (h = 0, p = (u_char *)cp->t; (c = *p) != 0; p++)
756: h = (h << 5) + h + c;
757: lhp = &labels[h & LHMASK];
758: for (lh = *lhp; lh != NULL; lh = lh->lh_next)
759: if (lh->lh_hash == h && strcmp(cp->t, lh->lh_cmd->t) == 0)
760: err(COMPILE2, "duplicate label '%s'", cp->t);
761: lh = xmalloc(sizeof *lh);
762: lh->lh_next = *lhp;
763: lh->lh_hash = h;
764: lh->lh_cmd = cp;
765: lh->lh_ref = 0;
766: *lhp = lh;
767: }
768:
769: /*
770: * Find the label contained in the command l in the command linked
771: * list cp. L is excluded from the search. Return NULL if not found.
772: */
773: static struct s_command *
774: findlabel(name)
775: char *name;
776: {
777: register struct labhash *lh;
778: register u_char *p;
779: register u_int h, c;
780:
781: for (h = 0, p = (u_char *)name; (c = *p) != 0; p++)
782: h = (h << 5) + h + c;
783: for (lh = labels[h & LHMASK]; lh != NULL; lh = lh->lh_next) {
784: if (lh->lh_hash == h && strcmp(name, lh->lh_cmd->t) == 0) {
785: lh->lh_ref = 1;
786: return (lh->lh_cmd);
787: }
788: }
789: return (NULL);
790: }
791:
792: /*
793: * Warn about any unused labels. As a side effect, release the label hash
794: * table space.
795: */
796: static void
797: uselabel()
798: {
799: register struct labhash *lh, *next;
800: register int i;
801:
802: for (i = 0; i < LHSZ; i++) {
803: for (lh = labels[i]; lh != NULL; lh = next) {
804: next = lh->lh_next;
805: if (!lh->lh_ref)
806: err(WARNING, "unused label '%s'",
807: lh->lh_cmd->t);
808: free(lh);
809: }
810: }
811: }