11da177e4SLinus Torvalds /* 21da177e4SLinus Torvalds * time.h - NTFS time conversion functions. Part of the Linux-NTFS project. 31da177e4SLinus Torvalds * 4d8ec785eSAnton Altaparmakov * Copyright (c) 2001-2005 Anton Altaparmakov 51da177e4SLinus Torvalds * 61da177e4SLinus Torvalds * This program/include file is free software; you can redistribute it and/or 71da177e4SLinus Torvalds * modify it under the terms of the GNU General Public License as published 81da177e4SLinus Torvalds * by the Free Software Foundation; either version 2 of the License, or 91da177e4SLinus Torvalds * (at your option) any later version. 101da177e4SLinus Torvalds * 111da177e4SLinus Torvalds * This program/include file is distributed in the hope that it will be 121da177e4SLinus Torvalds * useful, but WITHOUT ANY WARRANTY; without even the implied warranty 131da177e4SLinus Torvalds * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 141da177e4SLinus Torvalds * GNU General Public License for more details. 151da177e4SLinus Torvalds * 161da177e4SLinus Torvalds * You should have received a copy of the GNU General Public License 171da177e4SLinus Torvalds * along with this program (in the main directory of the Linux-NTFS 181da177e4SLinus Torvalds * distribution in the file COPYING); if not, write to the Free Software 191da177e4SLinus Torvalds * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 201da177e4SLinus Torvalds */ 211da177e4SLinus Torvalds 221da177e4SLinus Torvalds #ifndef _LINUX_NTFS_TIME_H 231da177e4SLinus Torvalds #define _LINUX_NTFS_TIME_H 241da177e4SLinus Torvalds 251da177e4SLinus Torvalds #include <linux/time.h> /* For current_kernel_time(). */ 261da177e4SLinus Torvalds #include <asm/div64.h> /* For do_div(). */ 271da177e4SLinus Torvalds 281da177e4SLinus Torvalds #include "endian.h" 291da177e4SLinus Torvalds 301da177e4SLinus Torvalds #define NTFS_TIME_OFFSET ((s64)(369 * 365 + 89) * 24 * 3600 * 10000000) 311da177e4SLinus Torvalds 321da177e4SLinus Torvalds /** 331da177e4SLinus Torvalds * utc2ntfs - convert Linux UTC time to NTFS time 341da177e4SLinus Torvalds * @ts: Linux UTC time to convert to NTFS time 351da177e4SLinus Torvalds * 361da177e4SLinus Torvalds * Convert the Linux UTC time @ts to its corresponding NTFS time and return 371da177e4SLinus Torvalds * that in little endian format. 381da177e4SLinus Torvalds * 391da177e4SLinus Torvalds * Linux stores time in a struct timespec consisting of a time_t (long at 401da177e4SLinus Torvalds * present) tv_sec and a long tv_nsec where tv_sec is the number of 1-second 411da177e4SLinus Torvalds * intervals since 1st January 1970, 00:00:00 UTC and tv_nsec is the number of 421da177e4SLinus Torvalds * 1-nano-second intervals since the value of tv_sec. 431da177e4SLinus Torvalds * 441da177e4SLinus Torvalds * NTFS uses Microsoft's standard time format which is stored in a s64 and is 451da177e4SLinus Torvalds * measured as the number of 100-nano-second intervals since 1st January 1601, 461da177e4SLinus Torvalds * 00:00:00 UTC. 471da177e4SLinus Torvalds */ 481da177e4SLinus Torvalds static inline sle64 utc2ntfs(const struct timespec ts) 491da177e4SLinus Torvalds { 501da177e4SLinus Torvalds /* 511da177e4SLinus Torvalds * Convert the seconds to 100ns intervals, add the nano-seconds 521da177e4SLinus Torvalds * converted to 100ns intervals, and then add the NTFS time offset. 531da177e4SLinus Torvalds */ 541da177e4SLinus Torvalds return cpu_to_sle64((s64)ts.tv_sec * 10000000 + ts.tv_nsec / 100 + 551da177e4SLinus Torvalds NTFS_TIME_OFFSET); 561da177e4SLinus Torvalds } 571da177e4SLinus Torvalds 581da177e4SLinus Torvalds /** 591da177e4SLinus Torvalds * get_current_ntfs_time - get the current time in little endian NTFS format 601da177e4SLinus Torvalds * 611da177e4SLinus Torvalds * Get the current time from the Linux kernel, convert it to its corresponding 621da177e4SLinus Torvalds * NTFS time and return that in little endian format. 631da177e4SLinus Torvalds */ 641da177e4SLinus Torvalds static inline sle64 get_current_ntfs_time(void) 651da177e4SLinus Torvalds { 661da177e4SLinus Torvalds return utc2ntfs(current_kernel_time()); 671da177e4SLinus Torvalds } 681da177e4SLinus Torvalds 691da177e4SLinus Torvalds /** 701da177e4SLinus Torvalds * ntfs2utc - convert NTFS time to Linux time 711da177e4SLinus Torvalds * @time: NTFS time (little endian) to convert to Linux UTC 721da177e4SLinus Torvalds * 731da177e4SLinus Torvalds * Convert the little endian NTFS time @time to its corresponding Linux UTC 741da177e4SLinus Torvalds * time and return that in cpu format. 751da177e4SLinus Torvalds * 761da177e4SLinus Torvalds * Linux stores time in a struct timespec consisting of a time_t (long at 771da177e4SLinus Torvalds * present) tv_sec and a long tv_nsec where tv_sec is the number of 1-second 781da177e4SLinus Torvalds * intervals since 1st January 1970, 00:00:00 UTC and tv_nsec is the number of 791da177e4SLinus Torvalds * 1-nano-second intervals since the value of tv_sec. 801da177e4SLinus Torvalds * 811da177e4SLinus Torvalds * NTFS uses Microsoft's standard time format which is stored in a s64 and is 821da177e4SLinus Torvalds * measured as the number of 100 nano-second intervals since 1st January 1601, 831da177e4SLinus Torvalds * 00:00:00 UTC. 841da177e4SLinus Torvalds */ 851da177e4SLinus Torvalds static inline struct timespec ntfs2utc(const sle64 time) 861da177e4SLinus Torvalds { 871da177e4SLinus Torvalds struct timespec ts; 881da177e4SLinus Torvalds 891da177e4SLinus Torvalds /* Subtract the NTFS time offset. */ 90d8ec785eSAnton Altaparmakov u64 t = (u64)(sle64_to_cpu(time) - NTFS_TIME_OFFSET); 911da177e4SLinus Torvalds /* 921da177e4SLinus Torvalds * Convert the time to 1-second intervals and the remainder to 931da177e4SLinus Torvalds * 1-nano-second intervals. 941da177e4SLinus Torvalds */ 951da177e4SLinus Torvalds ts.tv_nsec = do_div(t, 10000000) * 100; 961da177e4SLinus Torvalds ts.tv_sec = t; 971da177e4SLinus Torvalds return ts; 981da177e4SLinus Torvalds } 991da177e4SLinus Torvalds 1001da177e4SLinus Torvalds #endif /* _LINUX_NTFS_TIME_H */ 101