1/* $OpenBSD: gmt2local.c,v 1.7 2015/11/15 20:35:36 mmcc Exp $ */ 2 3/* 4 * Copyright (c) 1997 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that: (1) source code distributions 9 * retain the above copyright notice and this paragraph in its entirety, (2) 10 * distributions including binary code include the above copyright notice and 11 * this paragraph in its entirety in the documentation or other materials 12 * provided with the distribution, and (3) all advertising materials mentioning 13 * features or use of this software display the following acknowledgement: 14 * ``This product includes software developed by the University of California, 15 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of 16 * the University nor the names of its contributors may be used to endorse 17 * or promote products derived from this software without specific prior 18 * written permission. 19 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED 20 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF 21 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. 22 */ 23 24#include <sys/types.h> 25#include <sys/time.h> 26 27#include <stdio.h> 28#ifdef TIME_WITH_SYS_TIME 29#include <time.h> 30#endif 31 32#ifdef HAVE_OS_PROTO_H 33#include "os-proto.h" 34#endif 35 36#include "gmt2local.h" 37#include "privsep.h" 38 39/* 40 * Returns the difference between gmt and local time in seconds. 41 * Use gmtime() and localtime() to keep things simple. 42 */ 43int32_t 44gmt2local(time_t t) 45{ 46 int dt, dir; 47 struct tm *gmt, *loc; 48 struct tm sgmt; 49 50 if (t == 0) 51 t = time(NULL); 52 gmt = &sgmt; 53 *gmt = *gmtime(&t); 54 loc = priv_localtime(&t); 55 dt = (loc->tm_hour - gmt->tm_hour) * 60 * 60 + 56 (loc->tm_min - gmt->tm_min) * 60; 57 58 /* 59 * If the year or julian day is different, we span 00:00 GMT 60 * and must add or subtract a day. Check the year first to 61 * avoid problems when the julian day wraps. 62 */ 63 dir = loc->tm_year - gmt->tm_year; 64 if (dir == 0) 65 dir = loc->tm_yday - gmt->tm_yday; 66 dt += dir * 24 * 60 * 60; 67 68 return (dt); 69} 70