From b72a75e993d60d50cb9ed067aaf83197b3b1c9e1 Mon Sep 17 00:00:00 2001
From: Sami Kerola
Date: Tue, 12 Jul 2016 22:21:10 +0100
Subject: lib: add timegm() portability function to lib/timeutils.c

Local timegm() is a replacement function in cases it is missing from libc
implementation.  Hopefully the replacement is never, or very rarely, used.

CC: Ruediger Meier <ruediger.meier@ga-group.nl>
Reviewed-by: J William Piggott <elseifthen@gmx.com>
Signed-off-by: Sami Kerola <kerolasa@iki.fi>
---
 configure.ac           |  1 +
 include/timeutils.h    |  4 ++++
 lib/timeutils.c        | 19 +++++++++++++++++++
 login-utils/utmpdump.c |  1 +
 4 files changed, 25 insertions(+)

diff --git a/configure.ac b/configure.ac
index 37599212c..2dc10e331 100644
--- a/configure.ac
+++ b/configure.ac
@@ -416,6 +416,7 @@ AC_CHECK_FUNCS([ \
 	strnlen \
 	sysconf \
 	sysinfo \
+	timegm \
 	usleep \
 	warn \
 	warnx \
diff --git a/include/timeutils.h b/include/timeutils.h
index 00d18200d..85fc228db 100644
--- a/include/timeutils.h
+++ b/include/timeutils.h
@@ -78,4 +78,8 @@ int time_is_thisyear(const time_t *t, struct timeval *now);
 
 int strtime_short(const time_t *t, struct timeval *now, int flags, char *buf, size_t bufsz);
 
+#ifndef HAVE_TIMEGM
+extern time_t timegm(struct tm *tm);
+#endif
+
 #endif /* UTIL_LINUX_TIME_UTIL_H */
diff --git a/lib/timeutils.c b/lib/timeutils.c
index ea5c0aad8..d38970c10 100644
--- a/lib/timeutils.c
+++ b/lib/timeutils.c
@@ -20,6 +20,7 @@
 
 #include <assert.h>
 #include <ctype.h>
+#include <stdlib.h>
 #include <string.h>
 #include <time.h>
 #include <sys/time.h>
@@ -460,6 +461,24 @@ int strtime_short(const time_t *t, struct timeval *now, int flags, char *buf, si
 	return rc <= 0 ? -1 : 0;
 }
 
+#ifndef HAVE_TIMEGM
+time_t timegm(struct tm *tm)
+{
+	const char *zone = getenv("TZ");
+	time_t ret;
+
+	setenv("TZ", "", 1);
+	tzset();
+	ret = mktime(tm);
+	if (zone)
+		setenv("TZ", zone, 1);
+	else
+		unsetenv("TZ");
+	tzset();
+	return ret;
+}
+#endif /* HAVE_TIMEGM */
+
 #ifdef TEST_PROGRAM_TIMEUTILS
 
 int main(int argc, char *argv[])
diff --git a/login-utils/utmpdump.c b/login-utils/utmpdump.c
index 91eb4fb55..8e4839346 100644
--- a/login-utils/utmpdump.c
+++ b/login-utils/utmpdump.c
@@ -45,6 +45,7 @@
 #include "timeutils.h"
 #include "xalloc.h"
 #include "closestream.h"
+#include "timeutils.h"
 
 static time_t strtotime(const char *s_time)
 {
-- 
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