sdb/time/timedb.c

	timedb.c revision 0c27b3fe77ac1d5094ba3521e8142d9e7973133f
/*
 * Copyright (C) 2000, 2001, 2004, 2007, 2011, 2014, 2016  Internet Systems Consortium, Inc. ("ISC")
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 */

/* $Id: timedb.c,v 1.12 2011/10/11 23:46:45 tbox Exp $ */

/*
 * A simple database driver that enables the server to return the
 * current time in a DNS record.
 */

#include <config.h>

#include <string.h>
#include <stdio.h>
#include <time.h>

#include <isc/print.h>
#include <isc/result.h>
#include <isc/util.h>

#include <dns/sdb.h>

#include <named/globals.h>

#include "timedb.h"

static dns_sdbimplementation_t *timedb = NULL;

/*
 * This database operates on relative names.
 *
 * "time" and "@" return the time in a TXT record.
 * "clock" is a CNAME to "time"
 * "current" is a DNAME to "@" (try time.current.time)
 */
#ifdef DNS_CLIENTINFO_VERSION
static isc_result_t
timedb_lookup(const char *zone, const char *name, void *dbdata,
          dns_sdblookup_t *lookup, dns_clientinfomethods_t *methods,
          dns_clientinfo_t *clientinfo)
#else
static isc_result_t
timedb_lookup(const char *zone, const char *name, void *dbdata,
          dns_sdblookup_t *lookup)
#endif /* DNS_CLIENTINFO_VERSION */
{
    isc_result_t result;

    UNUSED(zone);
    UNUSED(dbdata);
#ifdef DNS_CLIENTINFO_VERSION
    UNUSED(methods);
    UNUSED(clientinfo);
#endif /* DNS_CLIENTINFO_VERSION */

    if (strcmp(name, "@") == 0 || strcmp(name, "time") == 0) {
        time_t now = time(NULL);
        char buf[100];
        int n;

        /*
         * Call ctime to create the string, put it in quotes, and
         * remove the trailing newline.
         */
        n = snprintf(buf, sizeof(buf), "\"%s", ctime(&now));
        if (n < 0)
            return (ISC_R_FAILURE);
        buf[n - 1] = '\"';
        result = dns_sdb_putrr(lookup, "txt", 1, buf);
        if (result != ISC_R_SUCCESS)
            return (ISC_R_FAILURE);
    } else if (strcmp(name, "clock") == 0) {
        result = dns_sdb_putrr(lookup, "cname", 1, "time");
        if (result != ISC_R_SUCCESS)
            return (ISC_R_FAILURE);
    } else if (strcmp(name, "current") == 0) {
        result = dns_sdb_putrr(lookup, "dname", 1, "@");
        if (result != ISC_R_SUCCESS)
            return (ISC_R_FAILURE);
    } else
        return (ISC_R_NOTFOUND);

    return (ISC_R_SUCCESS);
}

/*
 * lookup() does not return SOA or NS records, so authority() must be defined.
 */
static isc_result_t
timedb_authority(const char *zone, void *dbdata, dns_sdblookup_t *lookup) {
    isc_result_t result;

    UNUSED(zone);
    UNUSED(dbdata);

    result = dns_sdb_putsoa(lookup, "localhost.", "root.localhost.", 0);
    if (result != ISC_R_SUCCESS)
        return (ISC_R_FAILURE);

    result = dns_sdb_putrr(lookup, "ns", 86400, "ns1.localdomain.");
    if (result != ISC_R_SUCCESS)
        return (ISC_R_FAILURE);
    result = dns_sdb_putrr(lookup, "ns", 86400, "ns2.localdomain.");
    if (result != ISC_R_SUCCESS)
        return (ISC_R_FAILURE);

    return (ISC_R_SUCCESS);
}

/*
 * This zone does not support zone transfer, so allnodes() is NULL.  There
 * is no database specific data, so create() and destroy() are NULL.
 */
static dns_sdbmethods_t timedb_methods = {
    timedb_lookup,
    timedb_authority,
    NULL,   /* allnodes */
    NULL,   /* create */
    NULL,   /* destroy */
    NULL    /* lookup2 */
};

/*
 * Wrapper around dns_sdb_register().
 */
isc_result_t
timedb_init(void) {
    unsigned int flags;
    flags = DNS_SDBFLAG_RELATIVEOWNER | DNS_SDBFLAG_RELATIVERDATA;
    return (dns_sdb_register("time", &timedb_methods, NULL, flags,
                 ns_g_mctx, &timedb));
}

/*
 * Wrapper around dns_sdb_unregister().
 */
void
timedb_clear(void) {
    if (timedb != NULL)
        dns_sdb_unregister(&timedb);
}