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Diffstat (limited to 'src/usr.sbin/rdate/ntpleaps.h')
-rw-r--r-- | src/usr.sbin/rdate/ntpleaps.h | 73 |
1 files changed, 73 insertions, 0 deletions
diff --git a/src/usr.sbin/rdate/ntpleaps.h b/src/usr.sbin/rdate/ntpleaps.h new file mode 100644 index 0000000..30dda83 --- /dev/null +++ b/src/usr.sbin/rdate/ntpleaps.h @@ -0,0 +1,73 @@ +/* $OpenBSD: ntpleaps.h,v 1.4 2007/11/25 16:40:04 jmc Exp $ */ + +/* + * Copyright (c) 2002 Thorsten Glaser. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * - Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * - Redistributions in binary form must reproduce the above + * copyright notice, this list of conditions and the following + * disclaimer in the documentation and/or other materials provided + * with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS + * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE + * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, + * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; + * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER + * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN + * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + * + */ + +/* Leap second support for SNTP clients + * This header file and its corresponding C file provide generic + * ability for NTP or SNTP clients to correctly handle leap seconds + * by reading them from an always existing file and subtracting the + * leap seconds from the NTP return value before setting the posix + * clock. This is fairly portable between operating systems and may + * be used for patching other ntp clients, too. The tzfile used is: + * /usr/share/zoneinfo/right/UTC which is available on any unix-like + * platform with the Olson tz library, which is necessary to get real + * leap second zoneinfo files and userland support anyways. + */ + +#ifndef _NTPLEAPS_H +#define _NTPLEAPS_H + +/* Offset between struct timeval.tv_sec and a tai64_t */ +#define NTPLEAPS_OFFSET (4611686018427387914ULL) + +/* Hide this ugly value from programmes */ +#define SEC_TO_TAI64(s) (NTPLEAPS_OFFSET + (u_int64_t)(s)) +#define TAI64_TO_SEC(t) ((t) - NTPLEAPS_OFFSET) + +/* Initializes the leap second table. Does not need to be called + * before usage of the subtract function, but calls ntpleaps_read. + * returns 0 on success, -1 on error (displays a warning on stderr) + */ +int ntpleaps_init(void); + +/* Re-reads the leap second table, thus consuming quite much time. + * Ought to be called from within daemons at least once a month to + * ensure the in-memory table is always up-to-date. + * returns 0 on success, -1 on error (leap seconds will not be available) + */ +int ntpleaps_read(void); + +/* Subtracts leap seconds from the given value (converts NTP time + * to posix clock tick time. + * returns 0 on success, -1 on error (time is unchanged), 1 on leap second + */ +int ntpleaps_sub(u_int64_t *); + +#endif |