/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
 * All rights reserved.
 *
 * 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 project 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 PROJECT 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 PROJECT 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.
 */

#include "namespace.h"
#include <netdb.h>
#if defined(NLS)
#include <nl_types.h>
#include <errno.h>
#include <limits.h>
#include <stdlib.h>
#include <string.h>
#include "reentrant.h"
#endif
#include "un-namespace.h"

/*
 * Entries EAI_ADDRFAMILY (1) and EAI_NODATA (7) were omitted from RFC 3493,
 * but are or may be used as extensions or in old code.
 */
static const char *const ai_errlist[] = {
	[0] =			"Success",
	[EAI_ADDRFAMILY] =	"Address family for hostname not supported",
	[EAI_AGAIN] =		"Name could not be resolved at this time",
	[EAI_BADFLAGS] =	"Flags parameter had an invalid value",
	[EAI_FAIL] =		"Non-recoverable failure in name resolution",
	[EAI_FAMILY] =		"Address family not recognized",
	[EAI_MEMORY] =		"Memory allocation failure",
	[EAI_NODATA] =		"No address associated with hostname",
	[EAI_NONAME] =		"Name does not resolve",
	[EAI_SERVICE] =		"Service was not recognized for socket type",
	[EAI_SOCKTYPE] =	"Intended socket type was not recognized",
	[EAI_SYSTEM] =		"System error returned in errno",
	[EAI_BADHINTS] =	"Invalid value for hints",
	[EAI_PROTOCOL] =	"Resolved protocol is unknown",
	[EAI_OVERFLOW] =	"Argument buffer overflow",
};

#if defined(NLS)
static char		gai_buf[NL_TEXTMAX];
static once_t		gai_init_once = ONCE_INITIALIZER;
static thread_key_t	gai_key;
static int		gai_keycreated = 0;

static void
gai_keycreate(void)
{
	gai_keycreated = thr_keycreate(&gai_key, free) == 0;
}
#endif

const char *
gai_strerror(int ecode)
{
#if defined(NLS)
	nl_catd catd;
	char *buf;
	int saved_errno;

	saved_errno = errno;
	if (thr_main() != 0)
		buf = gai_buf;
	else {
		if (thr_once(&gai_init_once, gai_keycreate) != 0 ||
		    !gai_keycreated)
			goto thr_err;
		if ((buf = thr_getspecific(gai_key)) == NULL) {
			if ((buf = malloc(sizeof(gai_buf))) == NULL)
				goto thr_err;
			if (thr_setspecific(gai_key, buf) != 0) {
				free(buf);
				goto thr_err;
			}
		}
	}

	catd = catopen("libc", NL_CAT_LOCALE);
	if (ecode > 0 && ecode < EAI_MAX)
		strlcpy(buf, catgets(catd, 3, ecode, ai_errlist[ecode]),
		    sizeof(gai_buf));
	else if (ecode == 0)
		strlcpy(buf, catgets(catd, 3, NL_MSGMAX - 1, "Success"),
		    sizeof(gai_buf));
	else
		strlcpy(buf, catgets(catd, 3, NL_MSGMAX, "Unknown error"),
		    sizeof(gai_buf));
	catclose(catd);
	errno = saved_errno;
	return (buf);

thr_err:
	errno = saved_errno;
#endif
	if (ecode >= 0 && ecode < EAI_MAX)
		return (ai_errlist[ecode]);
	return ("Unknown error");
}