1/*	$Id: mansearch.c,v 1.64 2016/01/08 15:02:54 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#include "config.h"
19
20#include <sys/mman.h>
21#include <sys/types.h>
22
23#include <assert.h>
24#if HAVE_ERR
25#include <err.h>
26#endif
27#include <errno.h>
28#include <fcntl.h>
29#include <getopt.h>
30#include <glob.h>
31#include <limits.h>
32#include <regex.h>
33#include <stdio.h>
34#include <stdint.h>
35#include <stddef.h>
36#include <stdlib.h>
37#include <string.h>
38#include <unistd.h>
39
40#include <sqlite3.h>
41#ifndef SQLITE_DETERMINISTIC
42#define SQLITE_DETERMINISTIC 0
43#endif
44
45#include "mandoc.h"
46#include "mandoc_aux.h"
47#include "mandoc_ohash.h"
48#include "manconf.h"
49#include "mansearch.h"
50
51extern int mansearch_keymax;
52extern const char *const mansearch_keynames[];
53
54#define	SQL_BIND_TEXT(_db, _s, _i, _v) \
55	do { if (SQLITE_OK != sqlite3_bind_text \
56		((_s), (_i)++, (_v), -1, SQLITE_STATIC)) \
57		errx((int)MANDOCLEVEL_SYSERR, "%s", sqlite3_errmsg((_db))); \
58	} while (0)
59#define	SQL_BIND_INT64(_db, _s, _i, _v) \
60	do { if (SQLITE_OK != sqlite3_bind_int64 \
61		((_s), (_i)++, (_v))) \
62		errx((int)MANDOCLEVEL_SYSERR, "%s", sqlite3_errmsg((_db))); \
63	} while (0)
64#define	SQL_BIND_BLOB(_db, _s, _i, _v) \
65	do { if (SQLITE_OK != sqlite3_bind_blob \
66		((_s), (_i)++, (&_v), sizeof(_v), SQLITE_STATIC)) \
67		errx((int)MANDOCLEVEL_SYSERR, "%s", sqlite3_errmsg((_db))); \
68	} while (0)
69
70struct	expr {
71	regex_t		 regexp;  /* compiled regexp, if applicable */
72	const char	*substr;  /* to search for, if applicable */
73	struct expr	*next;    /* next in sequence */
74	uint64_t	 bits;    /* type-mask */
75	int		 equal;   /* equality, not subsring match */
76	int		 open;    /* opening parentheses before */
77	int		 and;	  /* logical AND before */
78	int		 close;   /* closing parentheses after */
79};
80
81struct	match {
82	uint64_t	 pageid; /* identifier in database */
83	uint64_t	 bits; /* name type mask */
84	char		*desc; /* manual page description */
85	int		 form; /* bit field: formatted, zipped? */
86};
87
88static	void		 buildnames(const struct mansearch *,
89				struct manpage *, sqlite3 *,
90				sqlite3_stmt *, uint64_t,
91				const char *, int form);
92static	char		*buildoutput(sqlite3 *, sqlite3_stmt *,
93				 uint64_t, uint64_t);
94static	struct expr	*exprcomp(const struct mansearch *,
95				int, char *[]);
96static	void		 exprfree(struct expr *);
97static	struct expr	*exprterm(const struct mansearch *, char *, int);
98static	int		 manpage_compare(const void *, const void *);
99static	void		 sql_append(char **sql, size_t *sz,
100				const char *newstr, int count);
101static	void		 sql_match(sqlite3_context *context,
102				int argc, sqlite3_value **argv);
103static	void		 sql_regexp(sqlite3_context *context,
104				int argc, sqlite3_value **argv);
105static	char		*sql_statement(const struct expr *);
106
107
108int
109mansearch_setup(int start)
110{
111	static void	*pagecache;
112	int		 c;
113
114#define	PC_PAGESIZE	1280
115#define	PC_NUMPAGES	256
116
117	if (start) {
118		if (NULL != pagecache) {
119			warnx("pagecache already enabled");
120			return (int)MANDOCLEVEL_BADARG;
121		}
122
123		pagecache = mmap(NULL, PC_PAGESIZE * PC_NUMPAGES,
124		    PROT_READ | PROT_WRITE,
125		    MAP_SHARED | MAP_ANON, -1, 0);
126
127		if (MAP_FAILED == pagecache) {
128			warn("mmap");
129			pagecache = NULL;
130			return (int)MANDOCLEVEL_SYSERR;
131		}
132
133		c = sqlite3_config(SQLITE_CONFIG_PAGECACHE,
134		    pagecache, PC_PAGESIZE, PC_NUMPAGES);
135
136		if (SQLITE_OK == c)
137			return (int)MANDOCLEVEL_OK;
138
139		warnx("pagecache: %s", sqlite3_errstr(c));
140
141	} else if (NULL == pagecache) {
142		warnx("pagecache missing");
143		return (int)MANDOCLEVEL_BADARG;
144	}
145
146	if (-1 == munmap(pagecache, PC_PAGESIZE * PC_NUMPAGES)) {
147		warn("munmap");
148		pagecache = NULL;
149		return (int)MANDOCLEVEL_SYSERR;
150	}
151
152	pagecache = NULL;
153	return (int)MANDOCLEVEL_OK;
154}
155
156int
157mansearch(const struct mansearch *search,
158		const struct manpaths *paths,
159		int argc, char *argv[],
160		struct manpage **res, size_t *sz)
161{
162	int64_t		 pageid;
163	uint64_t	 outbit, iterbit;
164	char		 buf[PATH_MAX];
165	char		*sql;
166	struct manpage	*mpage;
167	struct expr	*e, *ep;
168	sqlite3		*db;
169	sqlite3_stmt	*s, *s2;
170	struct match	*mp;
171	struct ohash	 htab;
172	unsigned int	 idx;
173	size_t		 i, j, cur, maxres;
174	int		 c, chdir_status, getcwd_status, indexbit;
175
176	if (argc == 0 || (e = exprcomp(search, argc, argv)) == NULL) {
177		*sz = 0;
178		return 0;
179	}
180
181	cur = maxres = 0;
182	*res = NULL;
183
184	if (NULL != search->outkey) {
185		outbit = TYPE_Nd;
186		for (indexbit = 0, iterbit = 1;
187		     indexbit < mansearch_keymax;
188		     indexbit++, iterbit <<= 1) {
189			if (0 == strcasecmp(search->outkey,
190			    mansearch_keynames[indexbit])) {
191				outbit = iterbit;
192				break;
193			}
194		}
195	} else
196		outbit = 0;
197
198	/*
199	 * Remember the original working directory, if possible.
200	 * This will be needed if the second or a later directory
201	 * is given as a relative path.
202	 * Do not error out if the current directory is not
203	 * searchable: Maybe it won't be needed after all.
204	 */
205
206	if (getcwd(buf, PATH_MAX) == NULL) {
207		getcwd_status = 0;
208		(void)strlcpy(buf, strerror(errno), sizeof(buf));
209	} else
210		getcwd_status = 1;
211
212	sql = sql_statement(e);
213
214	/*
215	 * Loop over the directories (containing databases) for us to
216	 * search.
217	 * Don't let missing/bad databases/directories phase us.
218	 * In each, try to open the resident database and, if it opens,
219	 * scan it for our match expression.
220	 */
221
222	chdir_status = 0;
223	for (i = 0; i < paths->sz; i++) {
224		if (chdir_status && paths->paths[i][0] != '/') {
225			if ( ! getcwd_status) {
226				warnx("%s: getcwd: %s", paths->paths[i], buf);
227				continue;
228			} else if (chdir(buf) == -1) {
229				warn("%s", buf);
230				continue;
231			}
232		}
233		if (chdir(paths->paths[i]) == -1) {
234			warn("%s", paths->paths[i]);
235			continue;
236		}
237		chdir_status = 1;
238
239		c = sqlite3_open_v2(MANDOC_DB, &db,
240		    SQLITE_OPEN_READONLY, NULL);
241
242		if (SQLITE_OK != c) {
243			warn("%s/%s", paths->paths[i], MANDOC_DB);
244			sqlite3_close(db);
245			continue;
246		}
247
248		/*
249		 * Define the SQL functions for substring
250		 * and regular expression matching.
251		 */
252
253		c = sqlite3_create_function(db, "match", 2,
254		    SQLITE_UTF8 | SQLITE_DETERMINISTIC,
255		    NULL, sql_match, NULL, NULL);
256		assert(SQLITE_OK == c);
257		c = sqlite3_create_function(db, "regexp", 2,
258		    SQLITE_UTF8 | SQLITE_DETERMINISTIC,
259		    NULL, sql_regexp, NULL, NULL);
260		assert(SQLITE_OK == c);
261
262		j = 1;
263		c = sqlite3_prepare_v2(db, sql, -1, &s, NULL);
264		if (SQLITE_OK != c)
265			errx((int)MANDOCLEVEL_SYSERR,
266			    "%s", sqlite3_errmsg(db));
267
268		for (ep = e; NULL != ep; ep = ep->next) {
269			if (NULL == ep->substr) {
270				SQL_BIND_BLOB(db, s, j, ep->regexp);
271			} else
272				SQL_BIND_TEXT(db, s, j, ep->substr);
273			if (0 == ((TYPE_Nd | TYPE_Nm) & ep->bits))
274				SQL_BIND_INT64(db, s, j, ep->bits);
275		}
276
277		mandoc_ohash_init(&htab, 4, offsetof(struct match, pageid));
278
279		/*
280		 * Hash each entry on its [unique] document identifier.
281		 * This is a uint64_t.
282		 * Instead of using a hash function, simply convert the
283		 * uint64_t to a uint32_t, the hash value's type.
284		 * This gives good performance and preserves the
285		 * distribution of buckets in the table.
286		 */
287		while (SQLITE_ROW == (c = sqlite3_step(s))) {
288			pageid = sqlite3_column_int64(s, 2);
289			idx = ohash_lookup_memory(&htab,
290			    (char *)&pageid, sizeof(uint64_t),
291			    (uint32_t)pageid);
292
293			if (NULL != ohash_find(&htab, idx))
294				continue;
295
296			mp = mandoc_calloc(1, sizeof(struct match));
297			mp->pageid = pageid;
298			mp->form = sqlite3_column_int(s, 1);
299			mp->bits = sqlite3_column_int64(s, 3);
300			if (TYPE_Nd == outbit)
301				mp->desc = mandoc_strdup((const char *)
302				    sqlite3_column_text(s, 0));
303			ohash_insert(&htab, idx, mp);
304		}
305
306		if (SQLITE_DONE != c)
307			warnx("%s", sqlite3_errmsg(db));
308
309		sqlite3_finalize(s);
310
311		c = sqlite3_prepare_v2(db,
312		    "SELECT sec, arch, name, pageid FROM mlinks "
313		    "WHERE pageid=? ORDER BY sec, arch, name",
314		    -1, &s, NULL);
315		if (SQLITE_OK != c)
316			errx((int)MANDOCLEVEL_SYSERR,
317			    "%s", sqlite3_errmsg(db));
318
319		c = sqlite3_prepare_v2(db,
320		    "SELECT bits, key, pageid FROM keys "
321		    "WHERE pageid=? AND bits & ?",
322		    -1, &s2, NULL);
323		if (SQLITE_OK != c)
324			errx((int)MANDOCLEVEL_SYSERR,
325			    "%s", sqlite3_errmsg(db));
326
327		for (mp = ohash_first(&htab, &idx);
328				NULL != mp;
329				mp = ohash_next(&htab, &idx)) {
330			if (cur + 1 > maxres) {
331				maxres += 1024;
332				*res = mandoc_reallocarray(*res,
333				    maxres, sizeof(struct manpage));
334			}
335			mpage = *res + cur;
336			mpage->ipath = i;
337			mpage->bits = mp->bits;
338			mpage->sec = 10;
339			mpage->form = mp->form;
340			buildnames(search, mpage, db, s, mp->pageid,
341			    paths->paths[i], mp->form);
342			if (mpage->names != NULL) {
343				mpage->output = TYPE_Nd & outbit ?
344				    mp->desc : outbit ?
345				    buildoutput(db, s2, mp->pageid, outbit) :
346				    NULL;
347				cur++;
348			}
349			free(mp);
350		}
351
352		sqlite3_finalize(s);
353		sqlite3_finalize(s2);
354		sqlite3_close(db);
355		ohash_delete(&htab);
356
357		/*
358		 * In man(1) mode, prefer matches in earlier trees
359		 * over matches in later trees.
360		 */
361
362		if (cur && search->firstmatch)
363			break;
364	}
365	qsort(*res, cur, sizeof(struct manpage), manpage_compare);
366	if (chdir_status && getcwd_status && chdir(buf) == -1)
367		warn("%s", buf);
368	exprfree(e);
369	free(sql);
370	*sz = cur;
371	return 1;
372}
373
374void
375mansearch_free(struct manpage *res, size_t sz)
376{
377	size_t	 i;
378
379	for (i = 0; i < sz; i++) {
380		free(res[i].file);
381		free(res[i].names);
382		free(res[i].output);
383	}
384	free(res);
385}
386
387static int
388manpage_compare(const void *vp1, const void *vp2)
389{
390	const struct manpage	*mp1, *mp2;
391	int			 diff;
392
393	mp1 = vp1;
394	mp2 = vp2;
395	return (diff = mp2->bits - mp1->bits) ? diff :
396	    (diff = mp1->sec - mp2->sec) ? diff :
397	    strcasecmp(mp1->names, mp2->names);
398}
399
400static void
401buildnames(const struct mansearch *search, struct manpage *mpage,
402		sqlite3 *db, sqlite3_stmt *s,
403		uint64_t pageid, const char *path, int form)
404{
405	glob_t		 globinfo;
406	char		*firstname, *newnames, *prevsec, *prevarch;
407	const char	*oldnames, *sep1, *name, *sec, *sep2, *arch, *fsec;
408	size_t		 i;
409	int		 c, globres;
410
411	mpage->file = NULL;
412	mpage->names = NULL;
413	firstname = prevsec = prevarch = NULL;
414	i = 1;
415	SQL_BIND_INT64(db, s, i, pageid);
416	while (SQLITE_ROW == (c = sqlite3_step(s))) {
417
418		/* Decide whether we already have some names. */
419
420		if (NULL == mpage->names) {
421			oldnames = "";
422			sep1 = "";
423		} else {
424			oldnames = mpage->names;
425			sep1 = ", ";
426		}
427
428		/* Fetch the next name, rejecting sec/arch mismatches. */
429
430		sec = (const char *)sqlite3_column_text(s, 0);
431		if (search->sec != NULL && strcasecmp(sec, search->sec))
432			continue;
433		arch = (const char *)sqlite3_column_text(s, 1);
434		if (search->arch != NULL && *arch != '\0' &&
435		    strcasecmp(arch, search->arch))
436			continue;
437		name = (const char *)sqlite3_column_text(s, 2);
438
439		/* Remember the first section found. */
440
441		if (9 < mpage->sec && '1' <= *sec && '9' >= *sec)
442			mpage->sec = (*sec - '1') + 1;
443
444		/* If the section changed, append the old one. */
445
446		if (NULL != prevsec &&
447		    (strcmp(sec, prevsec) ||
448		     strcmp(arch, prevarch))) {
449			sep2 = '\0' == *prevarch ? "" : "/";
450			mandoc_asprintf(&newnames, "%s(%s%s%s)",
451			    oldnames, prevsec, sep2, prevarch);
452			free(mpage->names);
453			oldnames = mpage->names = newnames;
454			free(prevsec);
455			free(prevarch);
456			prevsec = prevarch = NULL;
457		}
458
459		/* Save the new section, to append it later. */
460
461		if (NULL == prevsec) {
462			prevsec = mandoc_strdup(sec);
463			prevarch = mandoc_strdup(arch);
464		}
465
466		/* Append the new name. */
467
468		mandoc_asprintf(&newnames, "%s%s%s",
469		    oldnames, sep1, name);
470		free(mpage->names);
471		mpage->names = newnames;
472
473		/* Also save the first file name encountered. */
474
475		if (mpage->file != NULL)
476			continue;
477
478		if (form & FORM_SRC) {
479			sep1 = "man";
480			fsec = sec;
481		} else {
482			sep1 = "cat";
483			fsec = "0";
484		}
485		sep2 = *arch == '\0' ? "" : "/";
486		mandoc_asprintf(&mpage->file, "%s/%s%s%s%s/%s.%s",
487		    path, sep1, sec, sep2, arch, name, fsec);
488		if (access(mpage->file, R_OK) != -1)
489			continue;
490
491		/* Handle unusual file name extensions. */
492
493		if (firstname == NULL)
494			firstname = mpage->file;
495		else
496			free(mpage->file);
497		mandoc_asprintf(&mpage->file, "%s/%s%s%s%s/%s.*",
498		    path, sep1, sec, sep2, arch, name);
499		globres = glob(mpage->file, 0, NULL, &globinfo);
500		free(mpage->file);
501		mpage->file = globres ? NULL :
502		    mandoc_strdup(*globinfo.gl_pathv);
503		globfree(&globinfo);
504	}
505	if (c != SQLITE_DONE)
506		warnx("%s", sqlite3_errmsg(db));
507	sqlite3_reset(s);
508
509	/* If none of the files is usable, use the first name. */
510
511	if (mpage->file == NULL)
512		mpage->file = firstname;
513	else if (mpage->file != firstname)
514		free(firstname);
515
516	/* Append one final section to the names. */
517
518	if (prevsec != NULL) {
519		sep2 = *prevarch == '\0' ? "" : "/";
520		mandoc_asprintf(&newnames, "%s(%s%s%s)",
521		    mpage->names, prevsec, sep2, prevarch);
522		free(mpage->names);
523		mpage->names = newnames;
524		free(prevsec);
525		free(prevarch);
526	}
527}
528
529static char *
530buildoutput(sqlite3 *db, sqlite3_stmt *s, uint64_t pageid, uint64_t outbit)
531{
532	char		*output, *newoutput;
533	const char	*oldoutput, *sep1, *data;
534	size_t		 i;
535	int		 c;
536
537	output = NULL;
538	i = 1;
539	SQL_BIND_INT64(db, s, i, pageid);
540	SQL_BIND_INT64(db, s, i, outbit);
541	while (SQLITE_ROW == (c = sqlite3_step(s))) {
542		if (NULL == output) {
543			oldoutput = "";
544			sep1 = "";
545		} else {
546			oldoutput = output;
547			sep1 = " # ";
548		}
549		data = (const char *)sqlite3_column_text(s, 1);
550		mandoc_asprintf(&newoutput, "%s%s%s",
551		    oldoutput, sep1, data);
552		free(output);
553		output = newoutput;
554	}
555	if (SQLITE_DONE != c)
556		warnx("%s", sqlite3_errmsg(db));
557	sqlite3_reset(s);
558	return output;
559}
560
561/*
562 * Implement substring match as an application-defined SQL function.
563 * Using the SQL LIKE or GLOB operators instead would be a bad idea
564 * because that would require escaping metacharacters in the string
565 * being searched for.
566 */
567static void
568sql_match(sqlite3_context *context, int argc, sqlite3_value **argv)
569{
570
571	assert(2 == argc);
572	sqlite3_result_int(context, NULL != strcasestr(
573	    (const char *)sqlite3_value_text(argv[1]),
574	    (const char *)sqlite3_value_text(argv[0])));
575}
576
577/*
578 * Implement regular expression match
579 * as an application-defined SQL function.
580 */
581static void
582sql_regexp(sqlite3_context *context, int argc, sqlite3_value **argv)
583{
584
585	assert(2 == argc);
586	sqlite3_result_int(context, !regexec(
587	    (regex_t *)sqlite3_value_blob(argv[0]),
588	    (const char *)sqlite3_value_text(argv[1]),
589	    0, NULL, 0));
590}
591
592static void
593sql_append(char **sql, size_t *sz, const char *newstr, int count)
594{
595	size_t		 newsz;
596
597	newsz = 1 < count ? (size_t)count : strlen(newstr);
598	*sql = mandoc_realloc(*sql, *sz + newsz + 1);
599	if (1 < count)
600		memset(*sql + *sz, *newstr, (size_t)count);
601	else
602		memcpy(*sql + *sz, newstr, newsz);
603	*sz += newsz;
604	(*sql)[*sz] = '\0';
605}
606
607/*
608 * Prepare the search SQL statement.
609 */
610static char *
611sql_statement(const struct expr *e)
612{
613	char		*sql;
614	size_t		 sz;
615	int		 needop;
616
617	sql = mandoc_strdup(e->equal ?
618	    "SELECT desc, form, pageid, bits "
619		"FROM mpages NATURAL JOIN names WHERE " :
620	    "SELECT desc, form, pageid, 0 FROM mpages WHERE ");
621	sz = strlen(sql);
622
623	for (needop = 0; NULL != e; e = e->next) {
624		if (e->and)
625			sql_append(&sql, &sz, " AND ", 1);
626		else if (needop)
627			sql_append(&sql, &sz, " OR ", 1);
628		if (e->open)
629			sql_append(&sql, &sz, "(", e->open);
630		sql_append(&sql, &sz,
631		    TYPE_Nd & e->bits
632		    ? (NULL == e->substr
633			? "desc REGEXP ?"
634			: "desc MATCH ?")
635		    : TYPE_Nm == e->bits
636		    ? (NULL == e->substr
637			? "pageid IN (SELECT pageid FROM names "
638			  "WHERE name REGEXP ?)"
639			: e->equal
640			? "name = ? "
641			: "pageid IN (SELECT pageid FROM names "
642			  "WHERE name MATCH ?)")
643		    : (NULL == e->substr
644			? "pageid IN (SELECT pageid FROM keys "
645			  "WHERE key REGEXP ? AND bits & ?)"
646			: "pageid IN (SELECT pageid FROM keys "
647			  "WHERE key MATCH ? AND bits & ?)"), 1);
648		if (e->close)
649			sql_append(&sql, &sz, ")", e->close);
650		needop = 1;
651	}
652
653	return sql;
654}
655
656/*
657 * Compile a set of string tokens into an expression.
658 * Tokens in "argv" are assumed to be individual expression atoms (e.g.,
659 * "(", "foo=bar", etc.).
660 */
661static struct expr *
662exprcomp(const struct mansearch *search, int argc, char *argv[])
663{
664	uint64_t	 mask;
665	int		 i, toopen, logic, igncase, toclose;
666	struct expr	*first, *prev, *cur, *next;
667
668	first = cur = NULL;
669	logic = igncase = toopen = toclose = 0;
670
671	for (i = 0; i < argc; i++) {
672		if (0 == strcmp("(", argv[i])) {
673			if (igncase)
674				goto fail;
675			toopen++;
676			toclose++;
677			continue;
678		} else if (0 == strcmp(")", argv[i])) {
679			if (toopen || logic || igncase || NULL == cur)
680				goto fail;
681			cur->close++;
682			if (0 > --toclose)
683				goto fail;
684			continue;
685		} else if (0 == strcmp("-a", argv[i])) {
686			if (toopen || logic || igncase || NULL == cur)
687				goto fail;
688			logic = 1;
689			continue;
690		} else if (0 == strcmp("-o", argv[i])) {
691			if (toopen || logic || igncase || NULL == cur)
692				goto fail;
693			logic = 2;
694			continue;
695		} else if (0 == strcmp("-i", argv[i])) {
696			if (igncase)
697				goto fail;
698			igncase = 1;
699			continue;
700		}
701		next = exprterm(search, argv[i], !igncase);
702		if (NULL == next)
703			goto fail;
704		if (NULL == first)
705			first = next;
706		else
707			cur->next = next;
708		prev = cur = next;
709
710		/*
711		 * Searching for descriptions must be split out
712		 * because they are stored in the mpages table,
713		 * not in the keys table.
714		 */
715
716		for (mask = TYPE_Nm; mask <= TYPE_Nd; mask <<= 1) {
717			if (mask & cur->bits && ~mask & cur->bits) {
718				next = mandoc_calloc(1,
719				    sizeof(struct expr));
720				memcpy(next, cur, sizeof(struct expr));
721				prev->open = 1;
722				cur->bits = mask;
723				cur->next = next;
724				cur = next;
725				cur->bits &= ~mask;
726			}
727		}
728		prev->and = (1 == logic);
729		prev->open += toopen;
730		if (cur != prev)
731			cur->close = 1;
732
733		toopen = logic = igncase = 0;
734	}
735	if ( ! (toopen || logic || igncase || toclose))
736		return first;
737
738fail:
739	if (NULL != first)
740		exprfree(first);
741	return NULL;
742}
743
744static struct expr *
745exprterm(const struct mansearch *search, char *buf, int cs)
746{
747	char		 errbuf[BUFSIZ];
748	struct expr	*e;
749	char		*key, *val;
750	uint64_t	 iterbit;
751	int		 i, irc;
752
753	if ('\0' == *buf)
754		return NULL;
755
756	e = mandoc_calloc(1, sizeof(struct expr));
757
758	if (search->argmode == ARG_NAME) {
759		e->bits = TYPE_Nm;
760		e->substr = buf;
761		e->equal = 1;
762		return e;
763	}
764
765	/*
766	 * Separate macro keys from search string.
767	 * If needed, request regular expression handling
768	 * by setting e->substr to NULL.
769	 */
770
771	if (search->argmode == ARG_WORD) {
772		e->bits = TYPE_Nm;
773		e->substr = NULL;
774#if HAVE_REWB_BSD
775		mandoc_asprintf(&val, "[[:<:]]%s[[:>:]]", buf);
776#elif HAVE_REWB_SYSV
777		mandoc_asprintf(&val, "\\<%s\\>", buf);
778#else
779		mandoc_asprintf(&val,
780		    "(^|[^a-zA-Z01-9_])%s([^a-zA-Z01-9_]|$)", buf);
781#endif
782		cs = 0;
783	} else if ((val = strpbrk(buf, "=~")) == NULL) {
784		e->bits = TYPE_Nm | TYPE_Nd;
785		e->substr = buf;
786	} else {
787		if (val == buf)
788			e->bits = TYPE_Nm | TYPE_Nd;
789		if ('=' == *val)
790			e->substr = val + 1;
791		*val++ = '\0';
792		if (NULL != strstr(buf, "arch"))
793			cs = 0;
794	}
795
796	/* Compile regular expressions. */
797
798	if (NULL == e->substr) {
799		irc = regcomp(&e->regexp, val,
800		    REG_EXTENDED | REG_NOSUB | (cs ? 0 : REG_ICASE));
801		if (search->argmode == ARG_WORD)
802			free(val);
803		if (irc) {
804			regerror(irc, &e->regexp, errbuf, sizeof(errbuf));
805			warnx("regcomp: %s", errbuf);
806			free(e);
807			return NULL;
808		}
809	}
810
811	if (e->bits)
812		return e;
813
814	/*
815	 * Parse out all possible fields.
816	 * If the field doesn't resolve, bail.
817	 */
818
819	while (NULL != (key = strsep(&buf, ","))) {
820		if ('\0' == *key)
821			continue;
822		for (i = 0, iterbit = 1;
823		     i < mansearch_keymax;
824		     i++, iterbit <<= 1) {
825			if (0 == strcasecmp(key,
826			    mansearch_keynames[i])) {
827				e->bits |= iterbit;
828				break;
829			}
830		}
831		if (i == mansearch_keymax) {
832			if (strcasecmp(key, "any")) {
833				free(e);
834				return NULL;
835			}
836			e->bits |= ~0ULL;
837		}
838	}
839
840	return e;
841}
842
843static void
844exprfree(struct expr *p)
845{
846	struct expr	*pp;
847
848	while (NULL != p) {
849		pp = p->next;
850		free(p);
851		p = pp;
852	}
853}
854