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Revision 1.45, Sun Aug 17 03:24:47 2014 UTC (9 years, 7 months ago) by schwarze
Branch: MAIN
Changes since 1.44: +29 -28 lines

Fully integrate apropos(1) into mandoc(1).
Switch the argmode on the progname, including man(1).
Provide -f and -k options to switch the argmode.
Store the argmode inside struct search, generalizing the flags.
Derive the deftype from the argmode when needed instead of storing it.
Store the outkey inside struct search instead of passing it alone.
While here, get rid of the trailing blanks in Makefile.depend.

/*	$Id: mansearch.c,v 1.45 2014/08/17 03:24:47 schwarze Exp $ */
/*
 * Copyright (c) 2012 Kristaps Dzonsons <kristaps@bsd.lv>
 * Copyright (c) 2013, 2014 Ingo Schwarze <schwarze@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
#include "config.h"

#include <sys/mman.h>
#include <sys/types.h>

#include <assert.h>
#include <fcntl.h>
#include <getopt.h>
#include <limits.h>
#include <regex.h>
#include <stdio.h>
#include <stdint.h>
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#if HAVE_OHASH
#include <ohash.h>
#else
#include "compat_ohash.h"
#endif
#include <sqlite3.h>
#ifndef SQLITE_DETERMINISTIC
#define SQLITE_DETERMINISTIC 0
#endif

#include "mandoc.h"
#include "mandoc_aux.h"
#include "manpath.h"
#include "mansearch.h"

extern int mansearch_keymax;
extern const char *const mansearch_keynames[];

#define	SQL_BIND_TEXT(_db, _s, _i, _v) \
	do { if (SQLITE_OK != sqlite3_bind_text \
		((_s), (_i)++, (_v), -1, SQLITE_STATIC)) \
		fprintf(stderr, "%s\n", sqlite3_errmsg((_db))); \
	} while (0)
#define	SQL_BIND_INT64(_db, _s, _i, _v) \
	do { if (SQLITE_OK != sqlite3_bind_int64 \
		((_s), (_i)++, (_v))) \
		fprintf(stderr, "%s\n", sqlite3_errmsg((_db))); \
	} while (0)
#define	SQL_BIND_BLOB(_db, _s, _i, _v) \
	do { if (SQLITE_OK != sqlite3_bind_blob \
		((_s), (_i)++, (&_v), sizeof(_v), SQLITE_STATIC)) \
		fprintf(stderr, "%s\n", sqlite3_errmsg((_db))); \
	} while (0)

struct	expr {
	regex_t		 regexp;  /* compiled regexp, if applicable */
	const char	*substr;  /* to search for, if applicable */
	struct expr	*next;    /* next in sequence */
	uint64_t	 bits;    /* type-mask */
	int		 equal;   /* equality, not subsring match */
	int		 open;    /* opening parentheses before */
	int		 and;	  /* logical AND before */
	int		 close;   /* closing parentheses after */
};

struct	match {
	uint64_t	 pageid; /* identifier in database */
	char		*desc; /* manual page description */
	int		 form; /* 0 == catpage */
};

static	void		 buildnames(struct manpage *, sqlite3 *,
				sqlite3_stmt *, uint64_t,
				const char *, int form);
static	char		*buildoutput(sqlite3 *, sqlite3_stmt *,
				 uint64_t, uint64_t);
static	void		*hash_alloc(size_t, void *);
static	void		 hash_free(void *, void *);
static	void		*hash_calloc(size_t, size_t, void *);
static	struct expr	*exprcomp(const struct mansearch *,
				int, char *[]);
static	void		 exprfree(struct expr *);
static	struct expr	*exprspec(struct expr *, uint64_t,
				 const char *, const char *);
static	struct expr	*exprterm(const struct mansearch *, char *, int);
static	int		 manpage_compare(const void *, const void *);
static	void		 sql_append(char **sql, size_t *sz,
				const char *newstr, int count);
static	void		 sql_match(sqlite3_context *context,
				int argc, sqlite3_value **argv);
static	void		 sql_regexp(sqlite3_context *context,
				int argc, sqlite3_value **argv);
static	char		*sql_statement(const struct expr *);


int
mansearch_setup(int start)
{
	static void	*pagecache;
	int		 c;

#define	PC_PAGESIZE	1280
#define	PC_NUMPAGES	256

	if (start) {
		if (NULL != pagecache) {
			fprintf(stderr, "pagecache already enabled\n");
			return((int)MANDOCLEVEL_BADARG);
		}

		pagecache = mmap(NULL, PC_PAGESIZE * PC_NUMPAGES,
		    PROT_READ | PROT_WRITE,
		    MAP_SHARED | MAP_ANON, -1, 0);

		if (MAP_FAILED == pagecache) {
			perror("mmap");
			pagecache = NULL;
			return((int)MANDOCLEVEL_SYSERR);
		}

		c = sqlite3_config(SQLITE_CONFIG_PAGECACHE,
		    pagecache, PC_PAGESIZE, PC_NUMPAGES);

		if (SQLITE_OK == c)
			return((int)MANDOCLEVEL_OK);

		fprintf(stderr, "pagecache: %s\n", sqlite3_errstr(c));

	} else if (NULL == pagecache) {
		fprintf(stderr, "pagecache missing\n");
		return((int)MANDOCLEVEL_BADARG);
	}

	if (-1 == munmap(pagecache, PC_PAGESIZE * PC_NUMPAGES)) {
		perror("munmap");
		pagecache = NULL;
		return((int)MANDOCLEVEL_SYSERR);
	}

	pagecache = NULL;
	return((int)MANDOCLEVEL_OK);
}

int
mansearch(const struct mansearch *search,
		const struct manpaths *paths,
		int argc, char *argv[],
		struct manpage **res, size_t *sz)
{
	int		 fd, rc, c, indexbit;
	int64_t		 pageid;
	uint64_t	 outbit, iterbit;
	char		 buf[PATH_MAX];
	char		*sql;
	struct manpage	*mpage;
	struct expr	*e, *ep;
	sqlite3		*db;
	sqlite3_stmt	*s, *s2;
	struct match	*mp;
	struct ohash_info info;
	struct ohash	 htab;
	unsigned int	 idx;
	size_t		 i, j, cur, maxres;

	info.calloc = hash_calloc;
	info.alloc = hash_alloc;
	info.free = hash_free;
	info.key_offset = offsetof(struct match, pageid);

	*sz = cur = maxres = 0;
	sql = NULL;
	*res = NULL;
	fd = -1;
	e = NULL;
	rc = 0;

	if (0 == argc)
		goto out;
	if (NULL == (e = exprcomp(search, argc, argv)))
		goto out;

	outbit = 0;
	if (NULL != search->outkey) {
		for (indexbit = 0, iterbit = 1;
		     indexbit < mansearch_keymax;
		     indexbit++, iterbit <<= 1) {
			if (0 == strcasecmp(search->outkey,
			    mansearch_keynames[indexbit])) {
				outbit = iterbit;
				break;
			}
		}
	}

	/*
	 * Save a descriptor to the current working directory.
	 * Since pathnames in the "paths" variable might be relative,
	 * and we'll be chdir()ing into them, we need to keep a handle
	 * on our current directory from which to start the chdir().
	 */

	if (NULL == getcwd(buf, PATH_MAX)) {
		perror("getcwd");
		goto out;
	} else if (-1 == (fd = open(buf, O_RDONLY, 0))) {
		perror(buf);
		goto out;
	}

	sql = sql_statement(e);

	/*
	 * Loop over the directories (containing databases) for us to
	 * search.
	 * Don't let missing/bad databases/directories phase us.
	 * In each, try to open the resident database and, if it opens,
	 * scan it for our match expression.
	 */

	for (i = 0; i < paths->sz; i++) {
		if (-1 == fchdir(fd)) {
			perror(buf);
			free(*res);
			break;
		} else if (-1 == chdir(paths->paths[i])) {
			perror(paths->paths[i]);
			continue;
		}

		c = sqlite3_open_v2(MANDOC_DB, &db,
		    SQLITE_OPEN_READONLY, NULL);

		if (SQLITE_OK != c) {
			perror(MANDOC_DB);
			sqlite3_close(db);
			continue;
		}

		/*
		 * Define the SQL functions for substring
		 * and regular expression matching.
		 */

		c = sqlite3_create_function(db, "match", 2,
		    SQLITE_UTF8 | SQLITE_DETERMINISTIC,
		    NULL, sql_match, NULL, NULL);
		assert(SQLITE_OK == c);
		c = sqlite3_create_function(db, "regexp", 2,
		    SQLITE_UTF8 | SQLITE_DETERMINISTIC,
		    NULL, sql_regexp, NULL, NULL);
		assert(SQLITE_OK == c);

		j = 1;
		c = sqlite3_prepare_v2(db, sql, -1, &s, NULL);
		if (SQLITE_OK != c)
			fprintf(stderr, "%s\n", sqlite3_errmsg(db));

		for (ep = e; NULL != ep; ep = ep->next) {
			if (NULL == ep->substr) {
				SQL_BIND_BLOB(db, s, j, ep->regexp);
			} else
				SQL_BIND_TEXT(db, s, j, ep->substr);
			if (0 == ((TYPE_Nd | TYPE_Nm) & ep->bits))
				SQL_BIND_INT64(db, s, j, ep->bits);
		}

		memset(&htab, 0, sizeof(struct ohash));
		ohash_init(&htab, 4, &info);

		/*
		 * Hash each entry on its [unique] document identifier.
		 * This is a uint64_t.
		 * Instead of using a hash function, simply convert the
		 * uint64_t to a uint32_t, the hash value's type.
		 * This gives good performance and preserves the
		 * distribution of buckets in the table.
		 */
		while (SQLITE_ROW == (c = sqlite3_step(s))) {
			pageid = sqlite3_column_int64(s, 2);
			idx = ohash_lookup_memory(&htab,
			    (char *)&pageid, sizeof(uint64_t),
			    (uint32_t)pageid);

			if (NULL != ohash_find(&htab, idx))
				continue;

			mp = mandoc_calloc(1, sizeof(struct match));
			mp->pageid = pageid;
			mp->form = sqlite3_column_int(s, 1);
			if (TYPE_Nd == outbit)
				mp->desc = mandoc_strdup((const char *)
				    sqlite3_column_text(s, 0));
			ohash_insert(&htab, idx, mp);
		}

		if (SQLITE_DONE != c)
			fprintf(stderr, "%s\n", sqlite3_errmsg(db));

		sqlite3_finalize(s);

		c = sqlite3_prepare_v2(db,
		    "SELECT sec, arch, name, pageid FROM mlinks "
		    "WHERE pageid=? ORDER BY sec, arch, name",
		    -1, &s, NULL);
		if (SQLITE_OK != c)
			fprintf(stderr, "%s\n", sqlite3_errmsg(db));

		c = sqlite3_prepare_v2(db,
		    "SELECT bits, key, pageid FROM keys "
		    "WHERE pageid=? AND bits & ?",
		    -1, &s2, NULL);
		if (SQLITE_OK != c)
			fprintf(stderr, "%s\n", sqlite3_errmsg(db));

		for (mp = ohash_first(&htab, &idx);
				NULL != mp;
				mp = ohash_next(&htab, &idx)) {
			if (cur + 1 > maxres) {
				maxres += 1024;
				*res = mandoc_reallocarray(*res,
				    maxres, sizeof(struct manpage));
			}
			mpage = *res + cur;
			mpage->sec = 10;
			mpage->form = mp->form;
			buildnames(mpage, db, s, mp->pageid,
			    paths->paths[i], mp->form);
			mpage->output = TYPE_Nd & outbit ?
			    mp->desc : outbit ?
			    buildoutput(db, s2, mp->pageid, outbit) : NULL;

			free(mp);
			cur++;
		}

		sqlite3_finalize(s);
		sqlite3_finalize(s2);
		sqlite3_close(db);
		ohash_delete(&htab);
	}
	qsort(*res, cur, sizeof(struct manpage), manpage_compare);
	rc = 1;
out:
	if (-1 != fd) {
		if (-1 == fchdir(fd))
			perror(buf);
		close(fd);
	}
	exprfree(e);
	free(sql);
	*sz = cur;
	return(rc);
}

void
mansearch_free(struct manpage *res, size_t sz)
{
	size_t	 i;

	for (i = 0; i < sz; i++) {
		free(res[i].file);
		free(res[i].names);
		free(res[i].output);
	}
	free(res);
}

static int
manpage_compare(const void *vp1, const void *vp2)
{
	const struct manpage	*mp1, *mp2;
	int			 diff;

	mp1 = vp1;
	mp2 = vp2;
	diff = mp1->sec - mp2->sec;
	return(diff ? diff : strcasecmp(mp1->names, mp2->names));
}

static void
buildnames(struct manpage *mpage, sqlite3 *db, sqlite3_stmt *s,
		uint64_t pageid, const char *path, int form)
{
	char		*newnames, *prevsec, *prevarch;
	const char	*oldnames, *sep1, *name, *sec, *sep2, *arch, *fsec;
	size_t		 i;
	int		 c;

	mpage->file = NULL;
	mpage->names = NULL;
	prevsec = prevarch = NULL;
	i = 1;
	SQL_BIND_INT64(db, s, i, pageid);
	while (SQLITE_ROW == (c = sqlite3_step(s))) {

		/* Decide whether we already have some names. */

		if (NULL == mpage->names) {
			oldnames = "";
			sep1 = "";
		} else {
			oldnames = mpage->names;
			sep1 = ", ";
		}

		/* Fetch the next name. */

		sec = (const char *)sqlite3_column_text(s, 0);
		arch = (const char *)sqlite3_column_text(s, 1);
		name = (const char *)sqlite3_column_text(s, 2);

		/* Remember the first section found. */

		if (9 < mpage->sec && '1' <= *sec && '9' >= *sec)
			mpage->sec = (*sec - '1') + 1;

		/* If the section changed, append the old one. */

		if (NULL != prevsec &&
		    (strcmp(sec, prevsec) ||
		     strcmp(arch, prevarch))) {
			sep2 = '\0' == *prevarch ? "" : "/";
			mandoc_asprintf(&newnames, "%s(%s%s%s)",
			    oldnames, prevsec, sep2, prevarch);
			free(mpage->names);
			oldnames = mpage->names = newnames;
			free(prevsec);
			free(prevarch);
			prevsec = prevarch = NULL;
		}

		/* Save the new section, to append it later. */

		if (NULL == prevsec) {
			prevsec = mandoc_strdup(sec);
			prevarch = mandoc_strdup(arch);
		}

		/* Append the new name. */

		mandoc_asprintf(&newnames, "%s%s%s",
		    oldnames, sep1, name);
		free(mpage->names);
		mpage->names = newnames;

		/* Also save the first file name encountered. */

		if (NULL != mpage->file)
			continue;

		if (form) {
			sep1 = "man";
			fsec = sec;
		} else {
			sep1 = "cat";
			fsec = "0";
		}
		sep2 = '\0' == *arch ? "" : "/";
		mandoc_asprintf(&mpage->file, "%s/%s%s%s%s/%s.%s",
		    path, sep1, sec, sep2, arch, name, fsec);
	}
	if (SQLITE_DONE != c)
		fprintf(stderr, "%s\n", sqlite3_errmsg(db));
	sqlite3_reset(s);

	/* Append one final section to the names. */

	if (NULL != prevsec) {
		sep2 = '\0' == *prevarch ? "" : "/";
		mandoc_asprintf(&newnames, "%s(%s%s%s)",
		    mpage->names, prevsec, sep2, prevarch);
		free(mpage->names);
		mpage->names = newnames;
		free(prevsec);
		free(prevarch);
	}
}

static char *
buildoutput(sqlite3 *db, sqlite3_stmt *s, uint64_t pageid, uint64_t outbit)
{
	char		*output, *newoutput;
	const char	*oldoutput, *sep1, *data;
	size_t		 i;
	int		 c;

	output = NULL;
	i = 1;
	SQL_BIND_INT64(db, s, i, pageid);
	SQL_BIND_INT64(db, s, i, outbit);
	while (SQLITE_ROW == (c = sqlite3_step(s))) {
		if (NULL == output) {
			oldoutput = "";
			sep1 = "";
		} else {
			oldoutput = output;
			sep1 = " # ";
		}
		data = (const char *)sqlite3_column_text(s, 1);
		mandoc_asprintf(&newoutput, "%s%s%s",
		    oldoutput, sep1, data);
		free(output);
		output = newoutput;
	}
	if (SQLITE_DONE != c)
		fprintf(stderr, "%s\n", sqlite3_errmsg(db));
	sqlite3_reset(s);
	return(output);
}

/*
 * Implement substring match as an application-defined SQL function.
 * Using the SQL LIKE or GLOB operators instead would be a bad idea
 * because that would require escaping metacharacters in the string
 * being searched for.
 */
static void
sql_match(sqlite3_context *context, int argc, sqlite3_value **argv)
{

	assert(2 == argc);
	sqlite3_result_int(context, NULL != strcasestr(
	    (const char *)sqlite3_value_text(argv[1]),
	    (const char *)sqlite3_value_text(argv[0])));
}

/*
 * Implement regular expression match
 * as an application-defined SQL function.
 */
static void
sql_regexp(sqlite3_context *context, int argc, sqlite3_value **argv)
{

	assert(2 == argc);
	sqlite3_result_int(context, !regexec(
	    (regex_t *)sqlite3_value_blob(argv[0]),
	    (const char *)sqlite3_value_text(argv[1]),
	    0, NULL, 0));
}

static void
sql_append(char **sql, size_t *sz, const char *newstr, int count)
{
	size_t		 newsz;

	newsz = 1 < count ? (size_t)count : strlen(newstr);
	*sql = mandoc_realloc(*sql, *sz + newsz + 1);
	if (1 < count)
		memset(*sql + *sz, *newstr, (size_t)count);
	else
		memcpy(*sql + *sz, newstr, newsz);
	*sz += newsz;
	(*sql)[*sz] = '\0';
}

/*
 * Prepare the search SQL statement.
 */
static char *
sql_statement(const struct expr *e)
{
	char		*sql;
	size_t		 sz;
	int		 needop;

	sql = mandoc_strdup(
	    "SELECT desc, form, pageid FROM mpages WHERE ");
	sz = strlen(sql);

	for (needop = 0; NULL != e; e = e->next) {
		if (e->and)
			sql_append(&sql, &sz, " AND ", 1);
		else if (needop)
			sql_append(&sql, &sz, " OR ", 1);
		if (e->open)
			sql_append(&sql, &sz, "(", e->open);
		sql_append(&sql, &sz,
		    TYPE_Nd & e->bits
		    ? (NULL == e->substr
			? "desc REGEXP ?"
			: "desc MATCH ?")
		    : TYPE_Nm == e->bits
		    ? (NULL == e->substr
			? "pageid IN (SELECT pageid FROM names "
			  "WHERE name REGEXP ?)"
			: e->equal
			? "pageid IN (SELECT pageid FROM names "
			  "WHERE name = ?)"
			: "pageid IN (SELECT pageid FROM names "
			  "WHERE name MATCH ?)")
		    : (NULL == e->substr
			? "pageid IN (SELECT pageid FROM keys "
			  "WHERE key REGEXP ? AND bits & ?)"
			: "pageid IN (SELECT pageid FROM keys "
			  "WHERE key MATCH ? AND bits & ?)"), 1);
		if (e->close)
			sql_append(&sql, &sz, ")", e->close);
		needop = 1;
	}

	return(sql);
}

/*
 * Compile a set of string tokens into an expression.
 * Tokens in "argv" are assumed to be individual expression atoms (e.g.,
 * "(", "foo=bar", etc.).
 */
static struct expr *
exprcomp(const struct mansearch *search, int argc, char *argv[])
{
	uint64_t	 mask;
	int		 i, toopen, logic, igncase, toclose;
	struct expr	*first, *prev, *cur, *next;

	first = cur = NULL;
	logic = igncase = toclose = 0;
	toopen = NULL != search->sec || NULL != search->arch;

	for (i = 0; i < argc; i++) {
		if (0 == strcmp("(", argv[i])) {
			if (igncase)
				goto fail;
			toopen++;
			toclose++;
			continue;
		} else if (0 == strcmp(")", argv[i])) {
			if (toopen || logic || igncase || NULL == cur)
				goto fail;
			cur->close++;
			if (0 > --toclose)
				goto fail;
			continue;
		} else if (0 == strcmp("-a", argv[i])) {
			if (toopen || logic || igncase || NULL == cur)
				goto fail;
			logic = 1;
			continue;
		} else if (0 == strcmp("-o", argv[i])) {
			if (toopen || logic || igncase || NULL == cur)
				goto fail;
			logic = 2;
			continue;
		} else if (0 == strcmp("-i", argv[i])) {
			if (igncase)
				goto fail;
			igncase = 1;
			continue;
		}
		next = exprterm(search, argv[i], !igncase);
		if (NULL == next)
			goto fail;
		if (NULL == first)
			first = next;
		else
			cur->next = next;
		prev = cur = next;

		/*
		 * Searching for descriptions must be split out
		 * because they are stored in the mpages table,
		 * not in the keys table.
		 */

		for (mask = TYPE_Nm; mask <= TYPE_Nd; mask <<= 1) {
			if (mask & cur->bits && ~mask & cur->bits) {
				next = mandoc_calloc(1,
				    sizeof(struct expr));
				memcpy(next, cur, sizeof(struct expr));
				prev->open = 1;
				cur->bits = mask;
				cur->next = next;
				cur = next;
				cur->bits &= ~mask;
			}
		}
		prev->and = (1 == logic);
		prev->open += toopen;
		if (cur != prev)
			cur->close = 1;

		toopen = logic = igncase = 0;
	}
	if (toopen || logic || igncase || toclose)
		goto fail;

	if (NULL != search->sec || NULL != search->arch)
		cur->close++;
	if (NULL != search->arch)
		cur = exprspec(cur, TYPE_arch, search->arch, "^(%s|any)$");
	if (NULL != search->sec)
		exprspec(cur, TYPE_sec, search->sec, "^%s$");

	return(first);

fail:
	if (NULL != first)
		exprfree(first);
	return(NULL);
}

static struct expr *
exprspec(struct expr *cur, uint64_t key, const char *value,
		const char *format)
{
	char	 errbuf[BUFSIZ];
	char	*cp;
	int	 irc;

	mandoc_asprintf(&cp, format, value);
	cur->next = mandoc_calloc(1, sizeof(struct expr));
	cur = cur->next;
	cur->and = 1;
	cur->bits = key;
	if (0 != (irc = regcomp(&cur->regexp, cp,
	    REG_EXTENDED | REG_NOSUB | REG_ICASE))) {
		regerror(irc, &cur->regexp, errbuf, sizeof(errbuf));
		fprintf(stderr, "regcomp: %s\n", errbuf);
		cur->substr = value;
	}
	free(cp);
	return(cur);
}

static struct expr *
exprterm(const struct mansearch *search, char *buf, int cs)
{
	char		 errbuf[BUFSIZ];
	struct expr	*e;
	char		*key, *val;
	uint64_t	 iterbit;
	int		 i, irc;

	if ('\0' == *buf)
		return(NULL);

	e = mandoc_calloc(1, sizeof(struct expr));

	if (search->argmode == ARG_NAME) {
		e->bits = TYPE_Nm;
		e->substr = buf;
		e->equal = 1;
		return(e);
	}

	/*
	 * Separate macro keys from search string.
	 * If needed, request regular expression handling
	 * by setting e->substr to NULL.
	 */

	if (search->argmode == ARG_WORD) {
		e->bits = TYPE_Nm;
		e->substr = NULL;
		mandoc_asprintf(&val, "[[:<:]]%s[[:>:]]", buf);
	} else if ((val = strpbrk(buf, "=~")) == NULL) {
		e->bits = TYPE_Nm | TYPE_Nd;
		e->substr = buf;
	} else {
		if (val == buf)
			e->bits = TYPE_Nm | TYPE_Nd;
		if ('=' == *val)
			e->substr = val + 1;
		*val++ = '\0';
		if (NULL != strstr(buf, "arch"))
			cs = 0;
	}

	/* Compile regular expressions. */

	if (NULL == e->substr) {
		irc = regcomp(&e->regexp, val,
		    REG_EXTENDED | REG_NOSUB | (cs ? 0 : REG_ICASE));
		if (search->argmode == ARG_WORD)
			free(val);
		if (irc) {
			regerror(irc, &e->regexp, errbuf, sizeof(errbuf));
			fprintf(stderr, "regcomp: %s\n", errbuf);
			free(e);
			return(NULL);
		}
	}

	if (e->bits)
		return(e);

	/*
	 * Parse out all possible fields.
	 * If the field doesn't resolve, bail.
	 */

	while (NULL != (key = strsep(&buf, ","))) {
		if ('\0' == *key)
			continue;
		for (i = 0, iterbit = 1;
		     i < mansearch_keymax;
		     i++, iterbit <<= 1) {
			if (0 == strcasecmp(key,
			    mansearch_keynames[i])) {
				e->bits |= iterbit;
				break;
			}
		}
		if (i == mansearch_keymax) {
			if (strcasecmp(key, "any")) {
				free(e);
				return(NULL);
			}
			e->bits |= ~0ULL;
		}
	}

	return(e);
}

static void
exprfree(struct expr *p)
{
	struct expr	*pp;

	while (NULL != p) {
		pp = p->next;
		free(p);
		p = pp;
	}
}

static void *
hash_calloc(size_t nmemb, size_t sz, void *arg)
{

	return(mandoc_calloc(nmemb, sz));
}

static void *
hash_alloc(size_t sz, void *arg)
{

	return(mandoc_malloc(sz));
}

static void
hash_free(void *p, void *arg)
{

	free(p);
}