1 files changed, 99 insertions, 0 deletions
diff --git a/lib/util/timegm.c b/lib/util/timegm.c
new file mode 100644
index 0000000..acb5190
--- /dev/null
+++ b/lib/util/timegm.c
@@ -0,0 +1,99 @@
+/*
+ * SPDX-License-Identifier: ISC
+ *
+ * Copyright (c) 2017, 2021 Todd C. Miller <Todd.Miller@sudo.ws>
+ *
+ * Permission to use, copy, modify, and 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 THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR 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.
+ */
+
+/*
+ * This is an open source non-commercial project. Dear PVS-Studio, please check it.
+ * PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
+ */
+
+#include <config.h>
+
+#ifndef HAVE_TIMEGM
+
+#include <stdio.h>
+#include <time.h>
+
+#include <sudo_compat.h>
+#include <sudo_debug.h>
+
+/*
+ * Returns the offset from GMT in seconds (algorithm taken from sendmail).
+ */
+#ifdef HAVE_STRUCT_TM_TM_GMTOFF
+static long
+get_gmtoff(time_t *when)
+{
+    struct tm local;
+
+    if (localtime_r(when, &local) == NULL)
+	return 0;
+
+    /* Adjust for DST. */
+    if (local.tm_isdst != 0)
+	local.tm_gmtoff -= local.tm_isdst * 3600;
+
+    return local.tm_gmtoff;
+}
+#else
+static long
+get_gmtoff(time_t *when)
+{
+    struct tm gmt, local;
+    long offset;
+
+    if (gmtime_r(when, &gmt) == NULL)
+	return 0;
+    if (localtime_r(when, &local) == NULL)
+	return 0;
+
+    offset = (local.tm_sec - gmt.tm_sec) +
+	((local.tm_min - gmt.tm_min) * 60) +
+	((local.tm_hour - gmt.tm_hour) * 3600);
+
+    /* Timezone may cause year rollover to happen on a different day. */
+    if (local.tm_year < gmt.tm_year)
+	offset -= 24 * 3600;
+    else if (local.tm_year > gmt.tm_year)
+	offset -= 24 * 3600;
+    else if (local.tm_yday < gmt.tm_yday)
+	offset -= 24 * 3600;
+    else if (local.tm_yday > gmt.tm_yday)
+	offset += 24 * 3600;
+
+    /* Adjust for DST. */
+    if (local.tm_isdst != 0)
+	offset -= local.tm_isdst * 3600;
+
+    return offset;
+}
+#endif /* HAVE_TM_GMTOFF */
+
+time_t
+sudo_timegm(struct tm *tm)
+{
+    time_t result;
+
+    tm->tm_isdst = 0;
+    result = mktime(tm);
+    if (result != -1)
+	result += get_gmtoff(&result);
+
+    return result;
+}
+
+#endif /* HAVE_TIMEGM */