/*
 * Copyright (C) 2004, 2005, 2007  Internet Systems Consortium, Inc. ("ISC")
 * Copyright (C) 1999-2001  Internet Software Consortium.
 *
 * Permission to use, copy, modify, and/or 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.
 */

/* $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;
}