xref: /haiku/src/add-ons/kernel/file_systems/fat/bsd/kern/subr_clock.c (revision 909af08f4328301fbdef1ffb41f566c3b5bec0c7)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1988 University of Utah.
5  * Copyright (c) 1982, 1990, 1993
6  *	The Regents of the University of California.  All rights reserved.
7  *
8  * This code is derived from software contributed to Berkeley by
9  * the Systems Programming Group of the University of Utah Computer
10  * Science Department.
11  *
12  * Redistribution and use in source and binary forms, with or without
13  * modification, are permitted provided that the following conditions
14  * are met:
15  * 1. Redistributions of source code must retain the above copyright
16  *    notice, this list of conditions and the following disclaimer.
17  * 2. Redistributions in binary form must reproduce the above copyright
18  *    notice, this list of conditions and the following disclaimer in the
19  *    documentation and/or other materials provided with the distribution.
20  * 3. Neither the name of the University nor the names of its contributors
21  *    may be used to endorse or promote products derived from this software
22  *    without specific prior written permission.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34  * SUCH DAMAGE.
35  */
36 
37 
38 // Modified to support the Haiku FAT driver.
39 
40 #ifdef FS_SHELL
41 #include "fssh_api_wrapper.h"
42 #else
43 #include <real_time_clock.h>
44 #include <syscalls.h>
45 #include <time.h>
46 #endif
47 
48 #include "sys/param.h"
49 #include "sys/systm.h"
50 #include "sys/clock.h"
51 
52 
53 /*! @return The offset that will yield a UTC time_t when added to local time_t. Always returns 0 in
54 	fat_shell.
55 */
56 int
57 utc_offset(void)
58 {
59 #if defined USER
60 	time_t localTime;
61 	struct tm localTm;
62 	time(&localTime);
63 	localtime_r(&localTime, &localTm);
64 
65 	return localTm.tm_gmtoff * (-1);
66 #elif defined _KERNEL_MODE
67 	int32 offset;
68 	offset = get_timezone_offset();
69 
70 	return offset * (-1);
71 #endif
72 	return 0;
73 }
74