/*	$NetBSD: src/lib/libc/locale/setlocale.c,v 1.47 2004/07/21 20:27:46 tshiozak Exp $	*/
/*	$DragonFly: src/lib/libc/locale/setlocale.c,v 1.3 2005/04/21 16:36:34 joerg Exp $ */

/*
 * Copyright (c) 1991, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Paul Borman at Krystal Technologies.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#define _CTYPE_PRIVATE

#include <sys/types.h>
#include <sys/localedef.h>
#include <sys/stat.h>
#include <assert.h>
#include <ctype.h>
#include <limits.h>
#include <locale.h>
#include <paths.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "collate.h"
#include "rune.h"
#include "rune_local.h"

#include "../citrus/citrus_namespace.h"
#include "../citrus/citrus_region.h"
#include "../citrus/citrus_lookup.h"
#include "../citrus/citrus_bcs.h"

#define _LOCALE_ALIAS_NAME	"locale.alias"
#define _LOCALE_SYM_FORCE	"/force"

static char	*currentlocale(void);
static void	revert_to_default(int);
static int	force_locale_enable(int);
static int	load_locale_sub(int, const char *, int);
static char	*loadlocale(int);
static const char *__get_locale_env(int);

static void	revert_collate(void);
static int	load_ctype(const char *);
static void	revert_ctype(void);
static int	load_messages(const char *);

static const struct  {
	const char *name;
	int (*load_function)(const char *);
	void (*revert_function)(void);
} categories[] = {
	{ "LC_ALL", NULL, NULL },
	{ "LC_COLLATE", __collate_load_tables, revert_collate },
	{ "LC_CTYPE", load_ctype, revert_ctype },
	{ "LC_MONETARY", NULL, NULL },
	{ "LC_NUMERIC", NULL, NULL },
	{ "LC_TIME", NULL, NULL },
	{ "LC_MESSAGES", load_messages, NULL }
};

/*
 * Current locales for each category
 */
static char current_categories[_LC_LAST][32] = {
	"C",
        "C",
        "C",
        "C",
        "C",
	"C",
        "C"
};

/*
 * The locales we are going to try and load
 */
static char new_categories[_LC_LAST][32];

static char current_locale_string[_LC_LAST * 33];
const char *_PathLocale;

static int
load_ctype(const char *locale)
{
	if (_xpg4_setrunelocale(locale))
		return(-1);
	if (__runetable_to_netbsd_ctype(locale)) {
		/* very unfortunate, but need to go to "C" locale */
		revert_ctype();
		return(-1);
	}

	return(0);
}

static void
revert_ctype(void)
{
	_xpg4_setrunelocale("C");
	__runetable_to_netbsd_ctype("C");
}

static void
revert_collate(void)
{
	__collate_load_tables("C");
}

static int
load_messages(const char *locale)
{
	char name[PATH_MAX];
	struct stat st;

	/*
	 * XXX we don't have LC_MESSAGES support yet,
	 * but catopen may use the value of LC_MESSAGES category.
	 * so return successfully if locale directory is present.
	 */
	snprintf(name, sizeof(name), "%s/%s", _PathLocale, locale);

	if (stat(name, &st) < 0)
		return(-1);
	if (!S_ISDIR(st.st_mode))
		return(-1);
	return(0);
}

char *
setlocale(int category, const char *locale)
{
	int i, loadlocale_success;
	size_t len;
	const char *env, *r;

	__mb_len_max_runtime = 32;

	if (issetugid() ||
	    (!_PathLocale && !(_PathLocale = getenv("PATH_LOCALE"))))
		_PathLocale = _PATH_LOCALE;

	if (category < 0 || category >= (int)__arysize(categories))
		return(NULL);

	if (locale == NULL)
		return(category ?
		    current_categories[category] : currentlocale());

	/*
	 * Default to the current locale for everything.
	 */
	for (i = 1; i < _LC_LAST; ++i)
		strlcpy(new_categories[i], current_categories[i],
			sizeof(new_categories[i]));

	/*
	 * Now go fill up new_categories from the locale argument
	 */
	if (*locale == '\0') {
		if (category == LC_ALL) {
			for (i = 1; i < _LC_LAST; ++i) {
				env = __get_locale_env(i);
				strlcpy(new_categories[i], env,
				    sizeof(new_categories[i]));
			}
		}
		else {
			env = __get_locale_env(category);
			strlcpy(new_categories[category], env,
				sizeof(new_categories[category]));
		}
	} else if (category) {
		strlcpy(new_categories[category], locale,
		        sizeof(new_categories[category]));
	} else {
		if ((r = strchr(locale, '/')) == 0) {
			for (i = 1; i < _LC_LAST; ++i) {
				strlcpy(new_categories[i], locale,
				        sizeof(new_categories[i]));
			}
		} else {
			for (i = 1;;) {
				_DIAGASSERT(*r == '/' || *r == 0);
				_DIAGASSERT(*locale != 0);
				if (*locale == '/')
					return(NULL);	/* invalid format. */
				len = r - locale;
				if (len + 1 > sizeof(new_categories[i]))
					return(NULL);	/* too long */
				memcpy(new_categories[i], locale, len);
				new_categories[i][len] = '\0';
				if (*r == 0)
					break;
				_DIAGASSERT(*r == '/');
				if (*(locale = ++r) == 0)
					/* slash followed by NUL */
					return(NULL);
				/* skip until NUL or '/' */
				while (*r && *r != '/')
					r++;
				if (++i == _LC_LAST)
					return(NULL);	/* too many slashes. */
			}
			if (i + 1 != _LC_LAST)
				return(NULL);	/* too few slashes. */
		}
	}

	if (category)
		return(loadlocale(category));

	loadlocale_success = 0;
	for (i = 1; i < _LC_LAST; ++i) {
		if (loadlocale(i) != NULL)
			loadlocale_success = 1;
	}

	/*
	 * If all categories failed, return NULL; we don't need to back
	 * changes off, since none happened.
	 */
	if (!loadlocale_success)
		return(NULL);

	return(currentlocale());
}

static char *
currentlocale(void)
{
	int i;

	strlcpy(current_locale_string, current_categories[1],
		sizeof(current_locale_string));

	for (i = 2; i < _LC_LAST; ++i)
		if (strcmp(current_categories[1], current_categories[i])) {
			snprintf(current_locale_string,
			    sizeof(current_locale_string), "%s/%s/%s/%s/%s/%s",
			    current_categories[1], current_categories[2],
			    current_categories[3], current_categories[4],
			    current_categories[5], current_categories[6]);
			break;
		}
	return(current_locale_string);
}

static void
revert_to_default(int category)
{
	_DIAGASSERT(category >= 0 && category < _LC_LAST);

	if (categories[category].revert_function != NULL)
		categories[category].revert_function();
}

static int
force_locale_enable(int category)
{
	revert_to_default(category);

	return(0);
}

static int
load_locale_sub(int category, const char *locname, int isspecial)
{
	char name[PATH_MAX];

	/* check for the default locales */
	if (!strcmp(new_categories[category], "C") ||
	    !strcmp(new_categories[category], "POSIX")) {
		revert_to_default(category);
		return(0);
	}

	/* check whether special symbol */
	if (isspecial && _bcs_strcasecmp(locname, _LOCALE_SYM_FORCE) == 0)
		return(force_locale_enable(category));

	/* sanity check */
	if (strchr(locname, '/') != NULL)
		return(-1);

	snprintf(name, sizeof(name), "%s/%s/%s", _PathLocale, locname,
		 categories[category].name);

	if (category > 0 && category < (int)__arysize(categories) &&
	    categories[category].load_function != NULL)
		return(categories[category].load_function(locname));

	return(0);
}

static char *
loadlocale(int category)
{
	char aliaspath[PATH_MAX], loccat[PATH_MAX], buf[PATH_MAX];
	const char *alias;

	_DIAGASSERT(0 < category && category < __arysize(categories));

	if (strcmp(new_categories[category], current_categories[category]) == 0)
		return(current_categories[category]);

	/* (1) non-aliased file */
	if (!load_locale_sub(category, new_categories[category], 0))
		goto success;

	/* (2) lookup locname/catname type alias */
	snprintf(aliaspath, sizeof(aliaspath), "%s/" _LOCALE_ALIAS_NAME,
		 _PathLocale);
	snprintf(loccat, sizeof(loccat), "%s/%s", new_categories[category],
		 categories[category].name);
	alias = _lookup_alias(aliaspath, loccat, buf, sizeof(buf),
			      _LOOKUP_CASE_SENSITIVE);
	if (!load_locale_sub(category, alias, 1))
		goto success;

	/* (3) lookup locname type alias */
	alias = _lookup_alias(aliaspath, new_categories[category],
			      buf, sizeof(buf), _LOOKUP_CASE_SENSITIVE);
	if (!load_locale_sub(category, alias, 1))
		goto success;

	return(NULL);

success:
	strlcpy(current_categories[category], new_categories[category],
		sizeof(current_categories[category]));
	return(current_categories[category]);
}

static const char *
__get_locale_env(int category)
{
	const char *env;

	_DIAGASSERT(category != LC_ALL);

	/* 1. check LC_ALL. */
	env = getenv(categories[0].name);

	/* 2. check LC_* */
	if (env == NULL || *env == '\0')
		env = getenv(categories[category].name);

	/* 3. check LANG */
	if (env == NULL || *env == '\0')
		env = getenv("LANG");

	/* 4. if none is set, fall to "C" */
	if (env == NULL || *env == '\0' || strchr(env, '/'))
		env = "C";

	return(env);
}