1 /*
2  * Copyright (c) 2019, 2020 Tracey Emery <tracey@openbsd.org>
3  * Copyright (c) 2004, 2005 Esben Norby <norby@openbsd.org>
4  * Copyright (c) 2004 Ryan McBride <mcbride@openbsd.org>
5  * Copyright (c) 2002, 2003, 2004 Henning Brauer <henning@openbsd.org>
6  * Copyright (c) 2001 Markus Friedl.  All rights reserved.
7  * Copyright (c) 2001 Daniel Hartmeier.  All rights reserved.
8  * Copyright (c) 2001 Theo de Raadt.  All rights reserved.
9  *
10  * Permission to use, copy, modify, and distribute this software for any
11  * purpose with or without fee is hereby granted, provided that the above
12  * copyright notice and this permission notice appear in all copies.
13  *
14  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
15  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
16  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
17  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
18  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
19  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
20  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
21  */
22 
23 %{
24 #include <sys/types.h>
25 #include <sys/queue.h>
26 #include <sys/socket.h>
27 #include <sys/stat.h>
28 
29 #include <netinet/in.h>
30 
31 #include <arpa/inet.h>
32 
33 #include <ctype.h>
34 #include <err.h>
35 #include <errno.h>
36 #include <event.h>
37 #include <ifaddrs.h>
38 #include <imsg.h>
39 #include <limits.h>
40 #include <stdarg.h>
41 #include <stdio.h>
42 #include <string.h>
43 #include <syslog.h>
44 #include <unistd.h>
45 
46 #include "got_error.h"
47 #include "gotweb.h"
48 
49 TAILQ_HEAD(files, file)		 files = TAILQ_HEAD_INITIALIZER(files);
50 static struct file {
51 	TAILQ_ENTRY(file)	 entry;
52 	FILE			*stream;
53 	char			*name;
54 	size_t	 		 ungetpos;
55 	size_t			 ungetsize;
56 	u_char			*ungetbuf;
57 	int			 eof_reached;
58 	int			 lineno;
59 } *file, *topfile;
60 static const struct got_error*	pushfile(struct file**, const char *);
61 int		 popfile(void);
62 int		 yyparse(void);
63 int		 yylex(void);
64 int		 yyerror(const char *, ...)
65     __attribute__((__format__ (printf, 1, 2)))
66     __attribute__((__nonnull__ (1)));
67 int		 kw_cmp(const void *, const void *);
68 int		 lookup(char *);
69 int		 igetc(void);
70 int		 lgetc(int);
71 void		 lungetc(int);
72 int		 findeol(void);
73 
74 TAILQ_HEAD(symhead, sym)	 symhead = TAILQ_HEAD_INITIALIZER(symhead);
75 struct sym {
76 	TAILQ_ENTRY(sym)	 entry;
77 	int			 used;
78 	int			 persist;
79 	char			*nam;
80 	char			*val;
81 };
82 
83 int	 symset(const char *, const char *, int);
84 char	*symget(const char *);
85 
86 const struct got_error* gerror = NULL;
87 struct gotweb_config		*gw_conf;
88 
89 typedef struct {
90 	union {
91 		int64_t		 number;
92 		char		*string;
93 	} v;
94 	int lineno;
95 } YYSTYPE;
96 
97 %}
98 
99 %token	GOT_WWW_PATH GOT_MAX_REPOS GOT_SITE_NAME GOT_SITE_OWNER GOT_SITE_LINK
100 %token	GOT_LOGO GOT_LOGO_URL GOT_SHOW_REPO_OWNER GOT_SHOW_REPO_AGE
101 %token	GOT_SHOW_REPO_DESCRIPTION GOT_MAX_REPOS_DISPLAY GOT_REPOS_PATH
102 %token	GOT_MAX_COMMITS_DISPLAY ON ERROR GOT_SHOW_SITE_OWNER
103 %token	GOT_SHOW_REPO_CLONEURL
104 %token	<v.string>	STRING
105 %token	<v.number>	NUMBER
106 %type	<v.number>	boolean
107 %%
108 
109 grammar		: /* empty */
110 		| grammar '\n'
111 		| grammar main '\n'
112 		;
113 
114 boolean		: STRING {
115 			if (strcasecmp($1, "true") == 0 ||
116 			    strcasecmp($1, "yes") == 0)
117 				$$ = 1;
118 			else if (strcasecmp($1, "false") == 0 ||
119 			    strcasecmp($1, "off") == 0 ||
120 			    strcasecmp($1, "no") == 0)
121 				$$ = 0;
122 			else {
123 				yyerror("invalid boolean value '%s'", $1);
124 				free($1);
125 				YYERROR;
126 			}
127 			free($1);
128 		}
129 		| ON { $$ = 1; }
130 		;
131 main		: GOT_REPOS_PATH STRING {
132 			gw_conf->got_repos_path = strdup($2);
133 			if (gw_conf->got_repos_path == NULL) {
134 				free($2);
135 				yyerror("strdup");
136 				YYERROR;
137 			}
138 			free($2);
139 		}
140 		| GOT_WWW_PATH STRING {
141 			gw_conf->got_www_path = strdup($2);
142 			if (gw_conf->got_www_path == NULL) {
143 				free($2);
144 				yyerror("strdup");
145 				YYERROR;
146 			}
147 			free($2);
148 		}
149 		| GOT_MAX_REPOS NUMBER {
150 			if ($2 > 0)
151 				gw_conf->got_max_repos = $2;
152 		}
153 		| GOT_SITE_NAME STRING {
154 			gw_conf->got_site_name = strdup($2);
155 			if (gw_conf->got_site_name == NULL) {
156 				free($2);
157 				yyerror("strdup");
158 				YYERROR;
159 			}
160 			free($2);
161 		}
162 		| GOT_SITE_OWNER STRING {
163 			gw_conf->got_site_owner = strdup($2);
164 			if (gw_conf->got_site_owner == NULL) {
165 				free($2);
166 				yyerror("strdup");
167 				YYERROR;
168 			}
169 			free($2);
170 		}
171 		| GOT_SITE_LINK STRING {
172 			gw_conf->got_site_link = strdup($2);
173 			if (gw_conf->got_site_link == NULL) {
174 				free($2);
175 				yyerror("strdup");
176 				YYERROR;
177 			}
178 			free($2);
179 		}
180 		| GOT_LOGO STRING {
181 			gw_conf->got_logo = strdup($2);
182 			if (gw_conf->got_logo== NULL) {
183 				free($2);
184 				yyerror("strdup");
185 				YYERROR;
186 			}
187 			free($2);
188 		}
189 		| GOT_LOGO_URL STRING {
190 			gw_conf->got_logo_url = strdup($2);
191 			if (gw_conf->got_logo_url== NULL) {
192 				free($2);
193 				yyerror("strdup");
194 				YYERROR;
195 			}
196 			free($2);
197 		}
198 		| GOT_SHOW_SITE_OWNER boolean {
199 			gw_conf->got_show_site_owner = $2;
200 		}
201 		| GOT_SHOW_REPO_OWNER boolean {
202 			gw_conf->got_show_repo_owner = $2;
203 		}
204 		| GOT_SHOW_REPO_AGE boolean {
205 			gw_conf->got_show_repo_age = $2;
206 		}
207 		| GOT_SHOW_REPO_DESCRIPTION boolean {
208 			gw_conf->got_show_repo_description = $2;
209 		}
210 		| GOT_SHOW_REPO_CLONEURL boolean {
211 			gw_conf->got_show_repo_cloneurl = $2;
212 		}
213 		| GOT_MAX_REPOS_DISPLAY NUMBER {
214 			if ($2 > 0)
215 				gw_conf->got_max_repos_display = $2;
216 		}
217 		| GOT_MAX_COMMITS_DISPLAY NUMBER {
218 			if ($2 > 0)
219 				gw_conf->got_max_commits_display = $2;
220 		}
221 		;
222 %%
223 
224 struct keywords {
225 	const char	*k_name;
226 	int		 k_val;
227 };
228 
229 int
230 yyerror(const char *fmt, ...)
231 {
232 	va_list		 ap;
233 	char		*msg;
234 	char		*err = NULL;
235 
236 	va_start(ap, fmt);
237 	if (vasprintf(&msg, fmt, ap) == -1) {
238 		gerror =  got_error_from_errno("vasprintf");
239 		return 0;
240 	}
241 	va_end(ap);
242 	if (asprintf(&err, "%s:%d: %s", file->name, yylval.lineno, msg) == -1) {
243 		gerror = got_error_from_errno("asprintf");
244 		return(0);
245 	}
246 	gerror = got_error_msg(GOT_ERR_PARSE_CONFIG, strdup(err));
247 	free(msg);
248 	free(err);
249 	return(0);
250 }
251 
252 int
253 kw_cmp(const void *k, const void *e)
254 {
255 	return (strcmp(k, ((const struct keywords *)e)->k_name));
256 }
257 
258 int
259 lookup(char *s)
260 {
261 	/* This has to be sorted always. */
262 	static const struct keywords keywords[] = {
263 		{ "got_logo",			GOT_LOGO },
264 		{ "got_logo_url",		GOT_LOGO_URL },
265 		{ "got_max_commits_display",	GOT_MAX_COMMITS_DISPLAY },
266 		{ "got_max_repos",		GOT_MAX_REPOS },
267 		{ "got_max_repos_display",	GOT_MAX_REPOS_DISPLAY },
268 		{ "got_repos_path",		GOT_REPOS_PATH },
269 		{ "got_show_repo_age",		GOT_SHOW_REPO_AGE },
270 		{ "got_show_repo_cloneurl",	GOT_SHOW_REPO_CLONEURL },
271 		{ "got_show_repo_description",	GOT_SHOW_REPO_DESCRIPTION },
272 		{ "got_show_repo_owner",	GOT_SHOW_REPO_OWNER },
273 		{ "got_show_site_owner",	GOT_SHOW_SITE_OWNER },
274 		{ "got_site_link",		GOT_SITE_LINK },
275 		{ "got_site_name",		GOT_SITE_NAME },
276 		{ "got_site_owner",		GOT_SITE_OWNER },
277 		{ "got_www_path",		GOT_WWW_PATH },
278 	};
279 	const struct keywords	*p;
280 
281 	p = bsearch(s, keywords, sizeof(keywords)/sizeof(keywords[0]),
282 	    sizeof(keywords[0]), kw_cmp);
283 
284 	if (p)
285 		return (p->k_val);
286 	else
287 		return (STRING);
288 }
289 
290 #define START_EXPAND	1
291 #define DONE_EXPAND	2
292 
293 static int	expanding;
294 
295 int
296 igetc(void)
297 {
298 	int	c;
299 
300 	while (1) {
301 		if (file->ungetpos > 0)
302 			c = file->ungetbuf[--file->ungetpos];
303 		else
304 			c = getc(file->stream);
305 
306 		if (c == START_EXPAND)
307 			expanding = 1;
308 		else if (c == DONE_EXPAND)
309 			expanding = 0;
310 		else
311 			break;
312 	}
313 	return (c);
314 }
315 
316 int
317 lgetc(int quotec)
318 {
319 	int		c, next;
320 
321 	if (quotec) {
322 		if ((c = igetc()) == EOF) {
323 			yyerror("reached end of file while parsing "
324 			    "quoted string");
325 			if (file == topfile || popfile() == EOF)
326 				return (EOF);
327 			return (quotec);
328 		}
329 		return (c);
330 	}
331 
332 	while ((c = igetc()) == '\\') {
333 		next = igetc();
334 		if (next != '\n') {
335 			c = next;
336 			break;
337 		}
338 		yylval.lineno = file->lineno;
339 		file->lineno++;
340 	}
341 
342 	if (c == EOF) {
343 		/*
344 		 * Fake EOL when hit EOF for the first time. This gets line
345 		 * count right if last line in included file is syntactically
346 		 * invalid and has no newline.
347 		 */
348 		if (file->eof_reached == 0) {
349 			file->eof_reached = 1;
350 			return ('\n');
351 		}
352 		while (c == EOF) {
353 			if (file == topfile || popfile() == EOF)
354 				return (EOF);
355 			c = igetc();
356 		}
357 	}
358 	return (c);
359 }
360 
361 void
362 lungetc(int c)
363 {
364 	if (c == EOF)
365 		return;
366 
367 	if (file->ungetpos >= file->ungetsize) {
368 		void *p = reallocarray(file->ungetbuf, file->ungetsize, 2);
369 		if (p == NULL)
370 			err(1, "%s", __func__);
371 		file->ungetbuf = p;
372 		file->ungetsize *= 2;
373 	}
374 	file->ungetbuf[file->ungetpos++] = c;
375 }
376 
377 int
378 findeol(void)
379 {
380 	int	c;
381 
382 	/* Skip to either EOF or the first real EOL. */
383 	while (1) {
384 		c = lgetc(0);
385 		if (c == '\n') {
386 			file->lineno++;
387 			break;
388 		}
389 		if (c == EOF)
390 			break;
391 	}
392 	return (ERROR);
393 }
394 
395 int
396 yylex(void)
397 {
398 	unsigned char	 buf[8096];
399 	unsigned char	*p, *val;
400 	int		 quotec, next, c;
401 	int		 token;
402 
403 top:
404 	p = buf;
405 	while ((c = lgetc(0)) == ' ' || c == '\t')
406 		; /* nothing */
407 
408 	yylval.lineno = file->lineno;
409 	if (c == '#')
410 		while ((c = lgetc(0)) != '\n' && c != EOF)
411 			; /* nothing */
412 	if (c == '$' && !expanding) {
413 		while (1) {
414 			if ((c = lgetc(0)) == EOF)
415 				return (0);
416 
417 			if (p + 1 >= buf + sizeof(buf) - 1) {
418 				yyerror("string too long");
419 				return (findeol());
420 			}
421 			if (isalnum(c) || c == '_') {
422 				*p++ = c;
423 				continue;
424 			}
425 			*p = '\0';
426 			lungetc(c);
427 			break;
428 		}
429 		val = symget(buf);
430 		if (val == NULL) {
431 			yyerror("macro '%s' not defined", buf);
432 			return (findeol());
433 		}
434 		p = val + strlen(val) - 1;
435 		lungetc(DONE_EXPAND);
436 		while (p >= val) {
437 			lungetc(*p);
438 			p--;
439 		}
440 		lungetc(START_EXPAND);
441 		goto top;
442 	}
443 
444 	switch (c) {
445 	case '\'':
446 	case '"':
447 		quotec = c;
448 		while (1) {
449 			if ((c = lgetc(quotec)) == EOF)
450 				return (0);
451 			if (c == '\n') {
452 				file->lineno++;
453 				continue;
454 			} else if (c == '\\') {
455 				if ((next = lgetc(quotec)) == EOF)
456 					return (0);
457 				if (next == quotec || c == ' ' || c == '\t')
458 					c = next;
459 				else if (next == '\n') {
460 					file->lineno++;
461 					continue;
462 				} else
463 					lungetc(next);
464 			} else if (c == quotec) {
465 				*p = '\0';
466 				break;
467 			} else if (c == '\0') {
468 				yyerror("syntax error");
469 				return (findeol());
470 			}
471 			if (p + 1 >= buf + sizeof(buf) - 1) {
472 				yyerror("string too long");
473 				return (findeol());
474 			}
475 			*p++ = c;
476 		}
477 		yylval.v.string = strdup(buf);
478 		if (yylval.v.string == NULL)
479 			err(1, "%s", __func__);
480 		return (STRING);
481 	}
482 
483 #define allowed_to_end_number(x) \
484 	(isspace(x) || x == ')' || x ==',' || x == '/' || x == '}' || x == '=')
485 
486 	if (c == '-' || isdigit(c)) {
487 		do {
488 			*p++ = c;
489 			if ((unsigned)(p-buf) >= sizeof(buf)) {
490 				yyerror("string too long");
491 				return (findeol());
492 			}
493 		} while ((c = lgetc(0)) != EOF && isdigit(c));
494 		lungetc(c);
495 		if (p == buf + 1 && buf[0] == '-')
496 			goto nodigits;
497 		if (c == EOF || allowed_to_end_number(c)) {
498 			const char *errstr = NULL;
499 
500 			*p = '\0';
501 			yylval.v.number = strtonum(buf, LLONG_MIN,
502 			    LLONG_MAX, &errstr);
503 			if (errstr) {
504 				yyerror("\"%s\" invalid number: %s",
505 				    buf, errstr);
506 				return (findeol());
507 			}
508 			return (NUMBER);
509 		} else {
510 nodigits:
511 			while (p > buf + 1)
512 				lungetc(*--p);
513 			c = *--p;
514 			if (c == '-')
515 				return (c);
516 		}
517 	}
518 
519 #define allowed_in_string(x) \
520 	(isalnum(x) || (ispunct(x) && x != '(' && x != ')' && \
521 	x != '{' && x != '}' && \
522 	x != '!' && x != '=' && x != '#' && \
523 	x != ','))
524 
525 	if (isalnum(c) || c == ':' || c == '_') {
526 		do {
527 			*p++ = c;
528 			if ((unsigned)(p-buf) >= sizeof(buf)) {
529 				yyerror("string too long");
530 				return (findeol());
531 			}
532 		} while ((c = lgetc(0)) != EOF && (allowed_in_string(c)));
533 		lungetc(c);
534 		*p = '\0';
535 		if ((token = lookup(buf)) == STRING)
536 			if ((yylval.v.string = strdup(buf)) == NULL)
537 				err(1, "%s", __func__);
538 		return (token);
539 	}
540 	if (c == '\n') {
541 		yylval.lineno = file->lineno;
542 		file->lineno++;
543 	}
544 	if (c == EOF)
545 		return (0);
546 	return (c);
547 }
548 
549 static const struct got_error*
550 pushfile(struct file **nfile, const char *name)
551 {
552 	const struct got_error* error = NULL;
553 
554 	if (((*nfile) = calloc(1, sizeof(struct file))) == NULL)
555 		return got_error_from_errno2(__func__, "calloc");
556 	if (((*nfile)->name = strdup(name)) == NULL) {
557 		free(nfile);
558 		return got_error_from_errno2(__func__, "strdup");
559 	}
560 	if (((*nfile)->stream = fopen((*nfile)->name, "r")) == NULL) {
561 		char *msg = NULL;
562 		if (asprintf(&msg, "%s", (*nfile)->name) == -1)
563 			return got_error_from_errno("asprintf");
564 		error = got_error_msg(GOT_ERR_NO_CONFIG_FILE, msg);
565 		free((*nfile)->name);
566 		free((*nfile));
567 		free(msg);
568 		return error;
569 	}
570 	(*nfile)->lineno = TAILQ_EMPTY(&files) ? 1 : 0;
571 	(*nfile)->ungetsize = 16;
572 	(*nfile)->ungetbuf = malloc((*nfile)->ungetsize);
573 	if ((*nfile)->ungetbuf == NULL) {
574 		fclose((*nfile)->stream);
575 		free((*nfile)->name);
576 		free((*nfile));
577 		return got_error_from_errno2(__func__, "malloc");
578 	}
579 	TAILQ_INSERT_TAIL(&files, (*nfile), entry);
580 	return error;
581 }
582 
583 int
584 popfile(void)
585 {
586 	struct file	*prev = NULL;
587 
588 	TAILQ_REMOVE(&files, file, entry);
589 	fclose(file->stream);
590 	free(file->name);
591 	free(file->ungetbuf);
592 	free(file);
593 	file = prev;
594 	return (file ? 0 : EOF);
595 }
596 
597 const struct got_error*
598 parse_gotweb_config(struct gotweb_config **gconf, const char *filename)
599 {
600 	gw_conf = malloc(sizeof(struct gotweb_config));
601 	if (gw_conf == NULL) {
602 		gerror = got_error_from_errno("malloc");
603 		goto done;
604 	}
605 	gw_conf->got_repos_path = strdup(D_GOTPATH);
606 	if (gw_conf->got_repos_path == NULL) {
607 		gerror = got_error_from_errno("strdup");
608 		goto done;
609 	}
610 	gw_conf->got_www_path = strdup(D_GOTWWW);
611 	if (gw_conf->got_www_path == NULL) {
612 		gerror = got_error_from_errno("strdup");
613 		goto done;
614 	}
615 	gw_conf->got_site_name = strdup(D_SITENAME);
616 	if (gw_conf->got_site_name == NULL) {
617 		gerror = got_error_from_errno("strdup");
618 		goto done;
619 	}
620 	gw_conf->got_site_owner = strdup(D_SITEOWNER);
621 	if (gw_conf->got_site_owner == NULL) {
622 		gerror = got_error_from_errno("strdup");
623 		goto done;
624 	}
625 	gw_conf->got_site_link = strdup(D_SITELINK);
626 	if (gw_conf->got_site_link == NULL) {
627 		gerror = got_error_from_errno("strdup");
628 		goto done;
629 	}
630 	gw_conf->got_logo = strdup(D_GOTLOGO);
631 	if (gw_conf->got_logo == NULL) {
632 		gerror = got_error_from_errno("strdup");
633 		goto done;
634 	}
635 	gw_conf->got_logo_url = strdup(D_GOTURL);
636 	if (gw_conf->got_logo_url == NULL) {
637 		gerror = got_error_from_errno("strdup");
638 		goto done;
639 	}
640 	gw_conf->got_show_site_owner = D_SHOWSOWNER;
641 	gw_conf->got_show_repo_owner = D_SHOWROWNER;
642 	gw_conf->got_show_repo_age = D_SHOWAGE;
643 	gw_conf->got_show_repo_description = D_SHOWDESC;
644 	gw_conf->got_show_repo_cloneurl = D_SHOWURL;
645 	gw_conf->got_max_repos = D_MAXREPO;
646 	gw_conf->got_max_repos_display = D_MAXREPODISP;
647 	gw_conf->got_max_commits_display = D_MAXCOMMITDISP;
648 
649 	/*
650 	 * We don't require that the gotweb config file exists
651 	 * So reset gerror if it doesn't exist and goto done.
652 	 */
653 	gerror = pushfile(&file, filename);
654 	if (gerror && gerror->code == GOT_ERR_NO_CONFIG_FILE) {
655 		gerror = NULL;
656 		goto done;
657 	} else if (gerror)
658 		return gerror;
659 	topfile = file;
660 
661 	yyparse();
662 	popfile();
663 done:
664 	*gconf = gw_conf;
665 	return gerror;
666 }
667 
668 int
669 symset(const char *nam, const char *val, int persist)
670 {
671 	struct sym	*sym;
672 
673 	TAILQ_FOREACH(sym, &symhead, entry) {
674 		if (strcmp(nam, sym->nam) == 0)
675 			break;
676 	}
677 
678 	if (sym != NULL) {
679 		if (sym->persist == 1)
680 			return (0);
681 		else {
682 			free(sym->nam);
683 			free(sym->val);
684 			TAILQ_REMOVE(&symhead, sym, entry);
685 			free(sym);
686 		}
687 	}
688 	if ((sym = calloc(1, sizeof(*sym))) == NULL)
689 		return (-1);
690 
691 	sym->nam = strdup(nam);
692 	if (sym->nam == NULL) {
693 		free(sym);
694 		return (-1);
695 	}
696 	sym->val = strdup(val);
697 	if (sym->val == NULL) {
698 		free(sym->nam);
699 		free(sym);
700 		return (-1);
701 	}
702 	sym->used = 0;
703 	sym->persist = persist;
704 	TAILQ_INSERT_TAIL(&symhead, sym, entry);
705 	return (0);
706 }
707 
708 int
709 cmdline_symset(char *s)
710 {
711 	char	*sym, *val;
712 	int	ret;
713 	size_t	len;
714 
715 	if ((val = strrchr(s, '=')) == NULL)
716 		return (-1);
717 
718 	len = strlen(s) - strlen(val) + 1;
719 	if ((sym = malloc(len)) == NULL)
720 		errx(1, "cmdline_symset: malloc");
721 
722 	strlcpy(sym, s, len);
723 
724 	ret = symset(sym, val + 1, 1);
725 	free(sym);
726 
727 	return (ret);
728 }
729 
730 char *
731 symget(const char *nam)
732 {
733 	struct sym	*sym;
734 
735 	TAILQ_FOREACH(sym, &symhead, entry) {
736 		if (strcmp(nam, sym->nam) == 0) {
737 			sym->used = 1;
738 			return (sym->val);
739 		}
740 	}
741 	return (NULL);
742 }