1/*	$OpenBSD: _get_locname.c,v 1.1 2017/09/05 03:16:13 schwarze Exp $ */
2/*
3 * Copyright (c) 2017 Ingo Schwarze <schwarze@openbsd.org>
4 *
5 * Permission to use, copy, modify, and distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 */
17
18#include <errno.h>
19#include <locale.h>
20#include <paths.h>
21#include <stdio.h>
22#include <stdlib.h>
23#include <string.h>
24
25#include "rune.h"
26#include "rune_local.h"
27
28/*
29 * Supplement the input with locale(1) variables from the
30 * environment, validate it, and initialize UTF-8 when needed.
31 * Return NULL on error, "" if unset (for LC_ALL only),
32 * or the name of the locale that takes effect.
33 */
34const char *
35_get_locname(int category, const char *locname)
36{
37	static const char *const catname[_LC_LAST - 1] = {
38		"LC_COLLATE",	"LC_CTYPE",	"LC_MONETARY",
39		"LC_NUMERIC",	"LC_TIME",	"LC_MESSAGES"
40	};
41
42	FILE		*fp;
43	const char	*cp;
44	int		 save_errno;
45
46	/* For empty input, inspect the environment. */
47	if (*locname == '\0')
48		locname = getenv("LC_ALL");
49
50	if (category != LC_ALL) {
51		if (locname == NULL || *locname == '\0')
52			locname = getenv(catname[category - 1]);
53		if (locname == NULL || *locname == '\0')
54			locname = getenv("LANG");
55	}
56
57	/*
58	 * If still empty, treat LC_ALL as unset, but
59	 * fall back to the default locale for other categories.
60	 */
61	if (locname == NULL || *locname == '\0')
62		locname = category == LC_ALL ? "" : "C";
63
64	/* Accept and ignore all language and territory prefixes. */
65	if ((cp = strrchr(locname, '.')) == NULL)
66		return locname;
67
68	/* Reject all encodings except ASCII and UTF-8. */
69	if (strcmp(cp + 1, "UTF-8") != 0)
70		return NULL;
71
72	/* Initialize the UTF-8 character encoding locale, if needed. */
73	if (_Utf8RuneLocale != NULL)
74		return locname;
75	save_errno = errno;
76	if ((fp = fopen(_PATH_LOCALE "/UTF-8/LC_CTYPE", "re")) != NULL) {
77		_Utf8RuneLocale = _Read_RuneMagi(fp);
78		fclose(fp);
79	}
80	errno = save_errno;
81	return _Utf8RuneLocale == NULL ? NULL : locname;
82}
83