gnupg/jnlib/mischelp.c

89 lines
2.2 KiB
C

/* mischelp.c - Miscellaneous helper functions
* Copyright (C) 1998, 2000, 2001, 2006 Free Software Foundation, Inc.
*
* This file is part of JNLIB.
*
* JNLIB is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* JNLIB is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*/
#include <config.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include "libjnlib-config.h"
#include "mischelp.h"
/* A dummy function to prevent an empty compilation unit. Some
compilers bail out in this case. */
time_t
libjnlib_dummy_mischelp_func (void)
{
return time (NULL);
}
/*
timegm() is a GNU function that might not be available everywhere.
It's basically the inverse of gmtime() - you give it a struct tm,
and get back a time_t. It differs from mktime() in that it handles
the case where the struct tm is UTC and the local environment isn't.
Note, that this replacement implementaion is not thread-safe!
Some BSDs don't handle the putenv("foo") case properly, so we use
unsetenv if the platform has it to remove environment variables.
*/
#ifndef HAVE_TIMEGM
time_t
timegm (struct tm *tm)
{
time_t answer;
char *zone;
zone=getenv("TZ");
putenv("TZ=UTC");
tzset();
answer=mktime(tm);
if(zone)
{
static char *old_zone;
if (!old_zone)
{
old_zone = malloc(3+strlen(zone)+1);
if (old_zone)
{
strcpy(old_zone,"TZ=");
strcat(old_zone,zone);
}
}
if (old_zone)
putenv (old_zone);
}
else
#ifdef HAVE_UNSETENV
unsetenv("TZ");
#else
putenv("TZ");
#endif
tzset();
return answer;
}
#endif /*!HAVE_TIMEGM*/