isc/unix/stdtime.c

/*
 * Copyright (C) 1999-2001, 2004, 2005, 2007, 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: stdtime.c,v 1.19 2007/06/19 23:47:18 tbox Exp $ */

/*! \file */

#include <config.h>

#include <stddef.h> /* NULL */
#include <stdlib.h> /* NULL */
#include <syslog.h>

#include <sys/time.h>

#include <isc/stdtime.h>
#include <isc/util.h>

#ifndef ISC_FIX_TV_USEC
#define ISC_FIX_TV_USEC 1
#endif

#define US_PER_S 1000000

#if ISC_FIX_TV_USEC
static inline void
fix_tv_usec(struct timeval *tv) {
    isc_boolean_t fixed = ISC_FALSE;

    if (tv->tv_usec < 0) {
        fixed = ISC_TRUE;
        do {
            tv->tv_sec -= 1;
            tv->tv_usec += US_PER_S;
        } while (tv->tv_usec < 0);
    } else if (tv->tv_usec >= US_PER_S) {
        fixed = ISC_TRUE;
        do {
            tv->tv_sec += 1;
            tv->tv_usec -= US_PER_S;
        } while (tv->tv_usec >=US_PER_S);
    }
    /*
     * Call syslog directly as we are called from the logging functions.
     */
    if (fixed)
        (void)syslog(LOG_ERR, "gettimeofday returned bad tv_usec: corrected");
}
#endif

void
isc_stdtime_get(isc_stdtime_t *t) {
    struct timeval tv;

    /*
     * Set 't' to the number of seconds since 00:00:00 UTC, January 1,
     * 1970.
     */

    REQUIRE(t != NULL);

    RUNTIME_CHECK(gettimeofday(&tv, NULL) != -1);

#if ISC_FIX_TV_USEC
    fix_tv_usec(&tv);
    INSIST(tv.tv_usec >= 0);
#else
    INSIST(tv.tv_usec >= 0 && tv.tv_usec < US_PER_S);
#endif

    *t = (unsigned int)tv.tv_sec;
}