mansearch.c revision 1.50 
1/*	$OpenBSD: mansearch.c,v 1.50 2016/07/09 15:23:36 schwarze Exp $ */
2/*
3 * Copyright (c) 2012 Kristaps Dzonsons <kristaps@bsd.lv>
4 * Copyright (c) 2013, 2014, 2015 Ingo Schwarze <schwarze@openbsd.org>
5 *
6 * Permission to use, copy, modify, and distribute this software for any
7 * purpose with or without fee is hereby granted, provided that the above
8 * copyright notice and this permission notice appear in all copies.
9 *
10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHORS DISCLAIM ALL WARRANTIES
11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR
13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17 */
18
19#include <sys/mman.h>
20#include <sys/types.h>
21
22#include <assert.h>
23#include <err.h>
24#include <errno.h>
25#include <fcntl.h>
26#include <glob.h>
27#include <limits.h>
28#include <regex.h>
29#include <stdio.h>
30#include <stdint.h>
31#include <stddef.h>
32#include <stdlib.h>
33#include <string.h>
34#include <unistd.h>
35
36#include <sqlite3.h>
37
38#include "mandoc.h"
39#include "mandoc_aux.h"
40#include "mandoc_ohash.h"
41#include "manconf.h"
42#include "mansearch.h"
43
44extern int mansearch_keymax;
45extern const char *const mansearch_keynames[];
46
47#define	SQL_BIND_TEXT(_db, _s, _i, _v) \
48	do { if (SQLITE_OK != sqlite3_bind_text \
49		((_s), (_i)++, (_v), -1, SQLITE_STATIC)) \
50		errx((int)MANDOCLEVEL_SYSERR, "%s", sqlite3_errmsg((_db))); \
51	} while (0)
52#define	SQL_BIND_INT64(_db, _s, _i, _v) \
53	do { if (SQLITE_OK != sqlite3_bind_int64 \
54		((_s), (_i)++, (_v))) \
55		errx((int)MANDOCLEVEL_SYSERR, "%s", sqlite3_errmsg((_db))); \
56	} while (0)
57#define	SQL_BIND_BLOB(_db, _s, _i, _v) \
58	do { if (SQLITE_OK != sqlite3_bind_blob \
59		((_s), (_i)++, (&_v), sizeof(_v), SQLITE_STATIC)) \
60		errx((int)MANDOCLEVEL_SYSERR, "%s", sqlite3_errmsg((_db))); \
61	} while (0)
62
63struct	expr {
64	regex_t		 regexp;  /* compiled regexp, if applicable */
65	const char	*substr;  /* to search for, if applicable */
66	struct expr	*next;    /* next in sequence */
67	uint64_t	 bits;    /* type-mask */
68	int		 equal;   /* equality, not subsring match */
69	int		 open;    /* opening parentheses before */
70	int		 and;	  /* logical AND before */
71	int		 close;   /* closing parentheses after */
72};
73
74struct	match {
75	uint64_t	 pageid; /* identifier in database */
76	uint64_t	 bits; /* name type mask */
77	char		*desc; /* manual page description */
78	int		 form; /* bit field: formatted, zipped? */
79};
80
81static	void		 buildnames(const struct mansearch *,
82				struct manpage *, sqlite3 *,
83				sqlite3_stmt *, uint64_t,
84				const char *, int form);
85static	char		*buildoutput(sqlite3 *, sqlite3_stmt *,
86				 uint64_t, uint64_t);
87static	struct expr	*exprcomp(const struct mansearch *,
88				int, char *[]);
89static	void		 exprfree(struct expr *);
90static	struct expr	*exprterm(const struct mansearch *, char *, int);
91static	int		 manpage_compare(const void *, const void *);
92static	void		 sql_append(char **sql, size_t *sz,
93				const char *newstr, int count);
94static	void		 sql_match(sqlite3_context *context,
95				int argc, sqlite3_value **argv);
96static	void		 sql_regexp(sqlite3_context *context,
97				int argc, sqlite3_value **argv);
98static	char		*sql_statement(const struct expr *);
99
100
101int
102mansearch_setup(int start)
103{
104	static void	*pagecache;
105	int		 c;
106
107#define	PC_PAGESIZE	1280
108#define	PC_NUMPAGES	256
109
110	if (start) {
111		if (NULL != pagecache) {
112			warnx("pagecache already enabled");
113			return (int)MANDOCLEVEL_BADARG;
114		}
115
116		pagecache = mmap(NULL, PC_PAGESIZE * PC_NUMPAGES,
117		    PROT_READ | PROT_WRITE,
118		    MAP_SHARED | MAP_ANON, -1, 0);
119
120		if (MAP_FAILED == pagecache) {
121			warn("mmap");
122			pagecache = NULL;
123			return (int)MANDOCLEVEL_SYSERR;
124		}
125
126		c = sqlite3_config(SQLITE_CONFIG_PAGECACHE,
127		    pagecache, PC_PAGESIZE, PC_NUMPAGES);
128
129		if (SQLITE_OK == c)
130			return (int)MANDOCLEVEL_OK;
131
132		warnx("pagecache: %s", sqlite3_errstr(c));
133
134	} else if (NULL == pagecache) {
135		warnx("pagecache missing");
136		return (int)MANDOCLEVEL_BADARG;
137	}
138
139	if (-1 == munmap(pagecache, PC_PAGESIZE * PC_NUMPAGES)) {
140		warn("munmap");
141		pagecache = NULL;
142		return (int)MANDOCLEVEL_SYSERR;
143	}
144
145	pagecache = NULL;
146	return (int)MANDOCLEVEL_OK;
147}
148
149int
150mansearch(const struct mansearch *search,
151		const struct manpaths *paths,
152		int argc, char *argv[],
153		struct manpage **res, size_t *sz)
154{
155	int64_t		 pageid;
156	uint64_t	 outbit, iterbit;
157	char		 buf[PATH_MAX];
158	char		*sql;
159	struct manpage	*mpage;
160	struct expr	*e, *ep;
161	sqlite3		*db;
162	sqlite3_stmt	*s, *s2;
163	struct match	*mp;
164	struct ohash	 htab;
165	unsigned int	 idx;
166	size_t		 i, j, cur, maxres;
167	int		 c, chdir_status, getcwd_status, indexbit;
168
169	if (argc == 0 || (e = exprcomp(search, argc, argv)) == NULL) {
170		*sz = 0;
171		return 0;
172	}
173
174	cur = maxres = 0;
175	*res = NULL;
176
177	if (NULL != search->outkey) {
178		outbit = TYPE_Nd;
179		for (indexbit = 0, iterbit = 1;
180		     indexbit < mansearch_keymax;
181		     indexbit++, iterbit <<= 1) {
182			if (0 == strcasecmp(search->outkey,
183			    mansearch_keynames[indexbit])) {
184				outbit = iterbit;
185				break;
186			}
187		}
188	} else
189		outbit = 0;
190
191	/*
192	 * Remember the original working directory, if possible.
193	 * This will be needed if the second or a later directory
194	 * is given as a relative path.
195	 * Do not error out if the current directory is not
196	 * searchable: Maybe it won't be needed after all.
197	 */
198
199	if (getcwd(buf, PATH_MAX) == NULL) {
200		getcwd_status = 0;
201		(void)strlcpy(buf, strerror(errno), sizeof(buf));
202	} else
203		getcwd_status = 1;
204
205	sql = sql_statement(e);
206
207	/*
208	 * Loop over the directories (containing databases) for us to
209	 * search.
210	 * Don't let missing/bad databases/directories phase us.
211	 * In each, try to open the resident database and, if it opens,
212	 * scan it for our match expression.
213	 */
214
215	chdir_status = 0;
216	for (i = 0; i < paths->sz; i++) {
217		if (chdir_status && paths->paths[i][0] != '/') {
218			if ( ! getcwd_status) {
219				warnx("%s: getcwd: %s", paths->paths[i], buf);
220				continue;
221			} else if (chdir(buf) == -1) {
222				warn("%s", buf);
223				continue;
224			}
225		}
226		if (chdir(paths->paths[i]) == -1) {
227			warn("%s", paths->paths[i]);
228			continue;
229		}
230		chdir_status = 1;
231
232		c = sqlite3_open_v2(MANDOC_DB, &db,
233		    SQLITE_OPEN_READONLY, NULL);
234
235		if (SQLITE_OK != c) {
236			warn("%s/%s", paths->paths[i], MANDOC_DB);
237			sqlite3_close(db);
238			continue;
239		}
240
241		/*
242		 * Define the SQL functions for substring
243		 * and regular expression matching.
244		 */
245
246		c = sqlite3_create_function(db, "match", 2,
247		    SQLITE_UTF8 | SQLITE_DETERMINISTIC,
248		    NULL, sql_match, NULL, NULL);
249		assert(SQLITE_OK == c);
250		c = sqlite3_create_function(db, "regexp", 2,
251		    SQLITE_UTF8 | SQLITE_DETERMINISTIC,
252		    NULL, sql_regexp, NULL, NULL);
253		assert(SQLITE_OK == c);
254
255		j = 1;
256		c = sqlite3_prepare_v2(db, sql, -1, &s, NULL);
257		if (SQLITE_OK != c)
258			errx((int)MANDOCLEVEL_SYSERR,
259			    "%s", sqlite3_errmsg(db));
260
261		for (ep = e; NULL != ep; ep = ep->next) {
262			if (NULL == ep->substr) {
263				SQL_BIND_BLOB(db, s, j, ep->regexp);
264			} else
265				SQL_BIND_TEXT(db, s, j, ep->substr);
266			if (0 == ((TYPE_Nd | TYPE_Nm) & ep->bits))
267				SQL_BIND_INT64(db, s, j, ep->bits);
268		}
269
270		mandoc_ohash_init(&htab, 4, offsetof(struct match, pageid));
271
272		/*
273		 * Hash each entry on its [unique] document identifier.
274		 * This is a uint64_t.
275		 * Instead of using a hash function, simply convert the
276		 * uint64_t to a uint32_t, the hash value's type.
277		 * This gives good performance and preserves the
278		 * distribution of buckets in the table.
279		 */
280		while (SQLITE_ROW == (c = sqlite3_step(s))) {
281			pageid = sqlite3_column_int64(s, 2);
282			idx = ohash_lookup_memory(&htab,
283			    (char *)&pageid, sizeof(uint64_t),
284			    (uint32_t)pageid);
285
286			if (NULL != ohash_find(&htab, idx))
287				continue;
288
289			mp = mandoc_calloc(1, sizeof(struct match));
290			mp->pageid = pageid;
291			mp->form = sqlite3_column_int(s, 1);
292			mp->bits = sqlite3_column_int64(s, 3);
293			if (TYPE_Nd == outbit)
294				mp->desc = mandoc_strdup((const char *)
295				    sqlite3_column_text(s, 0));
296			ohash_insert(&htab, idx, mp);
297		}
298
299		if (SQLITE_DONE != c)
300			warnx("%s", sqlite3_errmsg(db));
301
302		sqlite3_finalize(s);
303
304		c = sqlite3_prepare_v2(db,
305		    "SELECT sec, arch, name, pageid FROM mlinks "
306		    "WHERE pageid=? ORDER BY sec, arch, name",
307		    -1, &s, NULL);
308		if (SQLITE_OK != c)
309			errx((int)MANDOCLEVEL_SYSERR,
310			    "%s", sqlite3_errmsg(db));
311
312		c = sqlite3_prepare_v2(db,
313		    "SELECT bits, key, pageid FROM keys "
314		    "WHERE pageid=? AND bits & ?",
315		    -1, &s2, NULL);
316		if (SQLITE_OK != c)
317			errx((int)MANDOCLEVEL_SYSERR,
318			    "%s", sqlite3_errmsg(db));
319
320		for (mp = ohash_first(&htab, &idx);
321				NULL != mp;
322				mp = ohash_next(&htab, &idx)) {
323			if (cur + 1 > maxres) {
324				maxres += 1024;
325				*res = mandoc_reallocarray(*res,
326				    maxres, sizeof(struct manpage));
327			}
328			mpage = *res + cur;
329			mpage->ipath = i;
330			mpage->bits = mp->bits;
331			mpage->sec = 10;
332			mpage->form = mp->form;
333			buildnames(search, mpage, db, s, mp->pageid,
334			    paths->paths[i], mp->form);
335			if (mpage->names != NULL) {
336				mpage->output = TYPE_Nd & outbit ?
337				    mp->desc : outbit ?
338				    buildoutput(db, s2, mp->pageid, outbit) :
339				    NULL;
340				cur++;
341			}
342			free(mp);
343		}
344
345		sqlite3_finalize(s);
346		sqlite3_finalize(s2);
347		sqlite3_close(db);
348		ohash_delete(&htab);
349
350		/*
351		 * In man(1) mode, prefer matches in earlier trees
352		 * over matches in later trees.
353		 */
354
355		if (cur && search->firstmatch)
356			break;
357	}
358	qsort(*res, cur, sizeof(struct manpage), manpage_compare);
359	if (chdir_status && getcwd_status && chdir(buf) == -1)
360		warn("%s", buf);
361	exprfree(e);
362	free(sql);
363	*sz = cur;
364	return 1;
365}
366
367void
368mansearch_free(struct manpage *res, size_t sz)
369{
370	size_t	 i;
371
372	for (i = 0; i < sz; i++) {
373		free(res[i].file);
374		free(res[i].names);
375		free(res[i].output);
376	}
377	free(res);
378}
379
380static int
381manpage_compare(const void *vp1, const void *vp2)
382{
383	const struct manpage	*mp1, *mp2;
384	int			 diff;
385
386	mp1 = vp1;
387	mp2 = vp2;
388	return (diff = mp2->bits - mp1->bits) ? diff :
389	    (diff = mp1->sec - mp2->sec) ? diff :
390	    strcasecmp(mp1->names, mp2->names);
391}
392
393static void
394buildnames(const struct mansearch *search, struct manpage *mpage,
395		sqlite3 *db, sqlite3_stmt *s,
396		uint64_t pageid, const char *path, int form)
397{
398	glob_t		 globinfo;
399	char		*firstname, *newnames, *prevsec, *prevarch;
400	const char	*oldnames, *sep1, *name, *sec, *sep2, *arch, *fsec;
401	size_t		 i;
402	int		 c, globres;
403
404	mpage->file = NULL;
405	mpage->names = NULL;
406	firstname = prevsec = prevarch = NULL;
407	i = 1;
408	SQL_BIND_INT64(db, s, i, pageid);
409	while (SQLITE_ROW == (c = sqlite3_step(s))) {
410
411		/* Decide whether we already have some names. */
412
413		if (NULL == mpage->names) {
414			oldnames = "";
415			sep1 = "";
416		} else {
417			oldnames = mpage->names;
418			sep1 = ", ";
419		}
420
421		/* Fetch the next name, rejecting sec/arch mismatches. */
422
423		sec = (const char *)sqlite3_column_text(s, 0);
424		if (search->sec != NULL && strcasecmp(sec, search->sec))
425			continue;
426		arch = (const char *)sqlite3_column_text(s, 1);
427		if (search->arch != NULL && *arch != '\0' &&
428		    strcasecmp(arch, search->arch))
429			continue;
430		name = (const char *)sqlite3_column_text(s, 2);
431
432		/* Remember the first section found. */
433
434		if (9 < mpage->sec && '1' <= *sec && '9' >= *sec)
435			mpage->sec = (*sec - '1') + 1;
436
437		/* If the section changed, append the old one. */
438
439		if (NULL != prevsec &&
440		    (strcmp(sec, prevsec) ||
441		     strcmp(arch, prevarch))) {
442			sep2 = '\0' == *prevarch ? "" : "/";
443			mandoc_asprintf(&newnames, "%s(%s%s%s)",
444			    oldnames, prevsec, sep2, prevarch);
445			free(mpage->names);
446			oldnames = mpage->names = newnames;
447			free(prevsec);
448			free(prevarch);
449			prevsec = prevarch = NULL;
450		}
451
452		/* Save the new section, to append it later. */
453
454		if (NULL == prevsec) {
455			prevsec = mandoc_strdup(sec);
456			prevarch = mandoc_strdup(arch);
457		}
458
459		/* Append the new name. */
460
461		mandoc_asprintf(&newnames, "%s%s%s",
462		    oldnames, sep1, name);
463		free(mpage->names);
464		mpage->names = newnames;
465
466		/* Also save the first file name encountered. */
467
468		if (mpage->file != NULL)
469			continue;
470
471		if (form & FORM_SRC) {
472			sep1 = "man";
473			fsec = sec;
474		} else {
475			sep1 = "cat";
476			fsec = "0";
477		}
478		sep2 = *arch == '\0' ? "" : "/";
479		mandoc_asprintf(&mpage->file, "%s/%s%s%s%s/%s.%s",
480		    path, sep1, sec, sep2, arch, name, fsec);
481		if (access(mpage->file, R_OK) != -1)
482			continue;
483
484		/* Handle unusual file name extensions. */
485
486		if (firstname == NULL)
487			firstname = mpage->file;
488		else
489			free(mpage->file);
490		mandoc_asprintf(&mpage->file, "%s/%s%s%s%s/%s.*",
491		    path, sep1, sec, sep2, arch, name);
492		globres = glob(mpage->file, 0, NULL, &globinfo);
493		free(mpage->file);
494		mpage->file = globres ? NULL :
495		    mandoc_strdup(*globinfo.gl_pathv);
496		globfree(&globinfo);
497	}
498	if (c != SQLITE_DONE)
499		warnx("%s", sqlite3_errmsg(db));
500	sqlite3_reset(s);
501
502	/* If none of the files is usable, use the first name. */
503
504	if (mpage->file == NULL)
505		mpage->file = firstname;
506	else if (mpage->file != firstname)
507		free(firstname);
508
509	/* Append one final section to the names. */
510
511	if (prevsec != NULL) {
512		sep2 = *prevarch == '\0' ? "" : "/";
513		mandoc_asprintf(&newnames, "%s(%s%s%s)",
514		    mpage->names, prevsec, sep2, prevarch);
515		free(mpage->names);
516		mpage->names = newnames;
517		free(prevsec);
518		free(prevarch);
519	}
520}
521
522static char *
523buildoutput(sqlite3 *db, sqlite3_stmt *s, uint64_t pageid, uint64_t outbit)
524{
525	char		*output, *newoutput;
526	const char	*oldoutput, *sep1, *data;
527	size_t		 i;
528	int		 c;
529
530	output = NULL;
531	i = 1;
532	SQL_BIND_INT64(db, s, i, pageid);
533	SQL_BIND_INT64(db, s, i, outbit);
534	while (SQLITE_ROW == (c = sqlite3_step(s))) {
535		if (NULL == output) {
536			oldoutput = "";
537			sep1 = "";
538		} else {
539			oldoutput = output;
540			sep1 = " # ";
541		}
542		data = (const char *)sqlite3_column_text(s, 1);
543		mandoc_asprintf(&newoutput, "%s%s%s",
544		    oldoutput, sep1, data);
545		free(output);
546		output = newoutput;
547	}
548	if (SQLITE_DONE != c)
549		warnx("%s", sqlite3_errmsg(db));
550	sqlite3_reset(s);
551	return output;
552}
553
554/*
555 * Implement substring match as an application-defined SQL function.
556 * Using the SQL LIKE or GLOB operators instead would be a bad idea
557 * because that would require escaping metacharacters in the string
558 * being searched for.
559 */
560static void
561sql_match(sqlite3_context *context, int argc, sqlite3_value **argv)
562{
563
564	assert(2 == argc);
565	sqlite3_result_int(context, NULL != strcasestr(
566	    (const char *)sqlite3_value_text(argv[1]),
567	    (const char *)sqlite3_value_text(argv[0])));
568}
569
570/*
571 * Implement regular expression match
572 * as an application-defined SQL function.
573 */
574static void
575sql_regexp(sqlite3_context *context, int argc, sqlite3_value **argv)
576{
577
578	assert(2 == argc);
579	sqlite3_result_int(context, !regexec(
580	    (regex_t *)sqlite3_value_blob(argv[0]),
581	    (const char *)sqlite3_value_text(argv[1]),
582	    0, NULL, 0));
583}
584
585static void
586sql_append(char **sql, size_t *sz, const char *newstr, int count)
587{
588	size_t		 newsz;
589
590	newsz = 1 < count ? (size_t)count : strlen(newstr);
591	*sql = mandoc_realloc(*sql, *sz + newsz + 1);
592	if (1 < count)
593		memset(*sql + *sz, *newstr, (size_t)count);
594	else
595		memcpy(*sql + *sz, newstr, newsz);
596	*sz += newsz;
597	(*sql)[*sz] = '\0';
598}
599
600/*
601 * Prepare the search SQL statement.
602 */
603static char *
604sql_statement(const struct expr *e)
605{
606	char		*sql;
607	size_t		 sz;
608	int		 needop;
609
610	sql = mandoc_strdup(e->equal ?
611	    "SELECT desc, form, pageid, bits "
612		"FROM mpages NATURAL JOIN names WHERE " :
613	    "SELECT desc, form, pageid, 0 FROM mpages WHERE ");
614	sz = strlen(sql);
615
616	for (needop = 0; NULL != e; e = e->next) {
617		if (e->and)
618			sql_append(&sql, &sz, " AND ", 1);
619		else if (needop)
620			sql_append(&sql, &sz, " OR ", 1);
621		if (e->open)
622			sql_append(&sql, &sz, "(", e->open);
623		sql_append(&sql, &sz,
624		    TYPE_Nd & e->bits
625		    ? (NULL == e->substr
626			? "desc REGEXP ?"
627			: "desc MATCH ?")
628		    : TYPE_Nm == e->bits
629		    ? (NULL == e->substr
630			? "pageid IN (SELECT pageid FROM names "
631			  "WHERE name REGEXP ?)"
632			: e->equal
633			? "name = ? "
634			: "pageid IN (SELECT pageid FROM names "
635			  "WHERE name MATCH ?)")
636		    : (NULL == e->substr
637			? "pageid IN (SELECT pageid FROM keys "
638			  "WHERE key REGEXP ? AND bits & ?)"
639			: "pageid IN (SELECT pageid FROM keys "
640			  "WHERE key MATCH ? AND bits & ?)"), 1);
641		if (e->close)
642			sql_append(&sql, &sz, ")", e->close);
643		needop = 1;
644	}
645
646	return sql;
647}
648
649/*
650 * Compile a set of string tokens into an expression.
651 * Tokens in "argv" are assumed to be individual expression atoms (e.g.,
652 * "(", "foo=bar", etc.).
653 */
654static struct expr *
655exprcomp(const struct mansearch *search, int argc, char *argv[])
656{
657	uint64_t	 mask;
658	int		 i, toopen, logic, igncase, toclose;
659	struct expr	*first, *prev, *cur, *next;
660
661	first = cur = NULL;
662	logic = igncase = toopen = toclose = 0;
663
664	for (i = 0; i < argc; i++) {
665		if (0 == strcmp("(", argv[i])) {
666			if (igncase)
667				goto fail;
668			toopen++;
669			toclose++;
670			continue;
671		} else if (0 == strcmp(")", argv[i])) {
672			if (toopen || logic || igncase || NULL == cur)
673				goto fail;
674			cur->close++;
675			if (0 > --toclose)
676				goto fail;
677			continue;
678		} else if (0 == strcmp("-a", argv[i])) {
679			if (toopen || logic || igncase || NULL == cur)
680				goto fail;
681			logic = 1;
682			continue;
683		} else if (0 == strcmp("-o", argv[i])) {
684			if (toopen || logic || igncase || NULL == cur)
685				goto fail;
686			logic = 2;
687			continue;
688		} else if (0 == strcmp("-i", argv[i])) {
689			if (igncase)
690				goto fail;
691			igncase = 1;
692			continue;
693		}
694		next = exprterm(search, argv[i], !igncase);
695		if (NULL == next)
696			goto fail;
697		if (NULL == first)
698			first = next;
699		else
700			cur->next = next;
701		prev = cur = next;
702
703		/*
704		 * Searching for descriptions must be split out
705		 * because they are stored in the mpages table,
706		 * not in the keys table.
707		 */
708
709		for (mask = TYPE_Nm; mask <= TYPE_Nd; mask <<= 1) {
710			if (mask & cur->bits && ~mask & cur->bits) {
711				next = mandoc_calloc(1,
712				    sizeof(struct expr));
713				memcpy(next, cur, sizeof(struct expr));
714				prev->open = 1;
715				cur->bits = mask;
716				cur->next = next;
717				cur = next;
718				cur->bits &= ~mask;
719			}
720		}
721		prev->and = (1 == logic);
722		prev->open += toopen;
723		if (cur != prev)
724			cur->close = 1;
725
726		toopen = logic = igncase = 0;
727	}
728	if ( ! (toopen || logic || igncase || toclose))
729		return first;
730
731fail:
732	if (NULL != first)
733		exprfree(first);
734	return NULL;
735}
736
737static struct expr *
738exprterm(const struct mansearch *search, char *buf, int cs)
739{
740	char		 errbuf[BUFSIZ];
741	struct expr	*e;
742	char		*key, *val;
743	uint64_t	 iterbit;
744	int		 i, irc;
745
746	if ('\0' == *buf)
747		return NULL;
748
749	e = mandoc_calloc(1, sizeof(struct expr));
750
751	if (search->argmode == ARG_NAME) {
752		e->bits = TYPE_Nm;
753		e->substr = buf;
754		e->equal = 1;
755		return e;
756	}
757
758	/*
759	 * Separate macro keys from search string.
760	 * If needed, request regular expression handling
761	 * by setting e->substr to NULL.
762	 */
763
764	if (search->argmode == ARG_WORD) {
765		e->bits = TYPE_Nm;
766		e->substr = NULL;
767		mandoc_asprintf(&val, "[[:<:]]%s[[:>:]]", buf);
768		cs = 0;
769	} else if ((val = strpbrk(buf, "=~")) == NULL) {
770		e->bits = TYPE_Nm | TYPE_Nd;
771		e->substr = buf;
772	} else {
773		if (val == buf)
774			e->bits = TYPE_Nm | TYPE_Nd;
775		if ('=' == *val)
776			e->substr = val + 1;
777		*val++ = '\0';
778		if (NULL != strstr(buf, "arch"))
779			cs = 0;
780	}
781
782	/* Compile regular expressions. */
783
784	if (NULL == e->substr) {
785		irc = regcomp(&e->regexp, val,
786		    REG_EXTENDED | REG_NOSUB | (cs ? 0 : REG_ICASE));
787		if (search->argmode == ARG_WORD)
788			free(val);
789		if (irc) {
790			regerror(irc, &e->regexp, errbuf, sizeof(errbuf));
791			warnx("regcomp: %s", errbuf);
792			free(e);
793			return NULL;
794		}
795	}
796
797	if (e->bits)
798		return e;
799
800	/*
801	 * Parse out all possible fields.
802	 * If the field doesn't resolve, bail.
803	 */
804
805	while (NULL != (key = strsep(&buf, ","))) {
806		if ('\0' == *key)
807			continue;
808		for (i = 0, iterbit = 1;
809		     i < mansearch_keymax;
810		     i++, iterbit <<= 1) {
811			if (0 == strcasecmp(key,
812			    mansearch_keynames[i])) {
813				e->bits |= iterbit;
814				break;
815			}
816		}
817		if (i == mansearch_keymax) {
818			if (strcasecmp(key, "any")) {
819				free(e);
820				return NULL;
821			}
822			e->bits |= ~0ULL;
823		}
824	}
825
826	return e;
827}
828
829static void
830exprfree(struct expr *p)
831{
832	struct expr	*pp;
833
834	while (NULL != p) {
835		pp = p->next;
836		free(p);
837		p = pp;
838	}
839}
840