/*
 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
 * Copyright (c) 1996-1999 by Internet Software Consortium.
 *
 * 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 ISC DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC 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.
 */

/*! \file
 * \brief
 * dns.c --- this is the top-level accessor function for the dns
 */

#include "port_before.h"

#include <stdlib.h>
#include <string.h>
#include <errno.h>

#include <sys/types.h>
#include <netinet/in.h>
#include <arpa/nameser.h>
#include <resolv.h>

#include <resolv.h>

#include <isc/memcluster.h>
#include <irs.h>

#include "port_after.h"

#include "irs_p.h"
#include "hesiod.h"
#include "dns_p.h"

/* forward */

static void             dns_close(struct irs_acc *);
static struct __res_state *     dns_res_get(struct irs_acc *);
static void             dns_res_set(struct irs_acc *, struct __res_state *,
                                void (*)(void *));

/* public */

struct irs_acc *
irs_dns_acc(const char *options) {
        struct irs_acc *acc;
        struct dns_p *dns;

        UNUSED(options);

        if (!(acc = memget(sizeof *acc))) {
                errno = ENOMEM;
                return (NULL);
        }
        memset(acc, 0x5e, sizeof *acc);
        if (!(dns = memget(sizeof *dns))) {
                errno = ENOMEM;
                memput(acc, sizeof *acc);
                return (NULL);
        }
        memset(dns, 0x5e, sizeof *dns);
        dns->res = NULL;
        dns->free_res = NULL;
        if (hesiod_init(&dns->hes_ctx) < 0) {
                /*
                 * We allow the dns accessor class to initialize
                 * despite hesiod failing to initialize correctly,
                 * since dns host queries don't depend on hesiod.
                 */
                dns->hes_ctx = NULL;
        }
        acc->private = dns;
#ifdef WANT_IRS_GR
        acc->gr_map = irs_dns_gr;
#else
        acc->gr_map = NULL;
#endif
#ifdef WANT_IRS_PW
        acc->pw_map = irs_dns_pw;
#else
        acc->pw_map = NULL;
#endif
        acc->sv_map = irs_dns_sv;
        acc->pr_map = irs_dns_pr;
        acc->ho_map = irs_dns_ho;
        acc->nw_map = irs_dns_nw;
        acc->ng_map = irs_nul_ng;
        acc->res_get = dns_res_get;
        acc->res_set = dns_res_set;
        acc->close = dns_close;
        return (acc);
}

/* methods */
static struct __res_state *
dns_res_get(struct irs_acc *this) {
        struct dns_p *dns = (struct dns_p *)this->private;

        if (dns->res == NULL) {
                struct __res_state *res;
                res = (struct __res_state *)malloc(sizeof *res);
                if (res == NULL)
                        return (NULL);
                memset(res, 0, sizeof *res);
                dns_res_set(this, res, free);
        }

        if ((dns->res->options & RES_INIT) == 0U &&
            res_ninit(dns->res) < 0)
                return (NULL);

        return (dns->res);
}

static void
dns_res_set(struct irs_acc *this, struct __res_state *res,
            void (*free_res)(void *)) {
        struct dns_p *dns = (struct dns_p *)this->private;

        if (dns->res && dns->free_res) {
                res_nclose(dns->res);
                (*dns->free_res)(dns->res);
        }
        dns->res = res;
        dns->free_res = free_res;
}

static void
dns_close(struct irs_acc *this) {
        struct dns_p *dns;

        dns = (struct dns_p *)this->private;
        if (dns->res && dns->free_res)
                (*dns->free_res)(dns->res);
        if (dns->hes_ctx)
                hesiod_end(dns->hes_ctx);
        memput(dns, sizeof *dns);
        memput(this, sizeof *this);
}