aboutsummaryrefslogtreecommitdiff
path: root/util-linux/hwclock.c
blob: 45959e7a19a4f9f3d40f4ca52c409fe9e6e305dc (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
/* vi: set sw=4 ts=4: */
/*
 * Mini hwclock implementation for busybox
 *
 * Copyright (C) 2002 Robert Griebl <griebl@gmx.de>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
*/


#include <sys/ioctl.h>
#include <sys/time.h>
#include <sys/utsname.h>
#include <ctype.h>
#include <fcntl.h>
#include <getopt.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <time.h>
#include <unistd.h>
#include "busybox.h"

/* Copied from linux/rtc.h to eliminate the kernel dependency */
struct linux_rtc_time {
	int tm_sec;
	int tm_min;
	int tm_hour;
	int tm_mday;
	int tm_mon;
	int tm_year;
	int tm_wday;
	int tm_yday;
	int tm_isdst;
};

#define RTC_SET_TIME   _IOW('p', 0x0a, struct linux_rtc_time) /* Set RTC time    */
#define RTC_RD_TIME    _IOR('p', 0x09, struct linux_rtc_time) /* Read RTC time   */

#ifdef CONFIG_FEATURE_HWCLOCK_LONGOPTIONS
# ifndef _GNU_SOURCE
#  define _GNU_SOURCE
# endif
#endif

static time_t read_rtc(int utc)
{
	int rtc;
	struct tm tm;
	char *oldtz = 0;
	time_t t = 0;

	if (( rtc = open ( "/dev/rtc", O_RDONLY )) < 0 ) {
		if (( rtc = open ( "/dev/misc/rtc", O_RDONLY )) < 0 )
			bb_perror_msg_and_die ( "Could not access RTC" );
	}
 	memset ( &tm, 0, sizeof( struct tm ));
	if ( ioctl ( rtc, RTC_RD_TIME, &tm ) < 0 )
		bb_perror_msg_and_die ( "Could not read time from RTC" );
	tm. tm_isdst = -1; // not known

	close ( rtc );

	if ( utc ) {
		oldtz = getenv ( "TZ" );
		setenv ( "TZ", "UTC 0", 1 );
		tzset ( );
	}

	t = mktime ( &tm );

	if ( utc ) {
		if ( oldtz )
			setenv ( "TZ", oldtz, 1 );
		else
			unsetenv ( "TZ" );
		tzset ( );
	}
	return t;
}

static void write_rtc(time_t t, int utc)
{
	int rtc;
	struct tm tm;

	if (( rtc = open ( "/dev/rtc", O_WRONLY )) < 0 ) {
		if (( rtc = open ( "/dev/misc/rtc", O_WRONLY )) < 0 )
			bb_perror_msg_and_die ( "Could not access RTC" );
	}

	tm = *( utc ? gmtime ( &t ) : localtime ( &t ));
	tm. tm_isdst = 0;

	if ( ioctl ( rtc, RTC_SET_TIME, &tm ) < 0 )
		bb_perror_msg_and_die ( "Could not set the RTC time" );

	close ( rtc );
}

static int show_clock(int utc)
{
	struct tm *ptm;
	time_t t;
	char buffer [64];

	t = read_rtc ( utc );
	ptm = localtime ( &t );  /* Sets 'tzname[]' */

	safe_strncpy ( buffer, ctime ( &t ), sizeof( buffer ));
	if ( buffer [0] )
		buffer [bb_strlen ( buffer ) - 1] = 0;

	//printf ( "%s  %.6f seconds %s\n", buffer, 0.0, utc ? "" : ( ptm-> tm_isdst ? tzname [1] : tzname [0] ));
	printf ( "%s  %.6f seconds\n", buffer, 0.0 );

	return 0;
}

static int to_sys_clock(int utc)
{
	struct timeval tv = { 0, 0 };
	const struct timezone tz = { timezone/60 - 60*daylight, 0 };

	tv. tv_sec = read_rtc ( utc );

	if ( settimeofday ( &tv, &tz ))
		bb_perror_msg_and_die ( "settimeofday() failed" );

	return 0;
}

static int from_sys_clock(int utc)
{
	struct timeval tv = { 0, 0 };
	struct timezone tz = { 0, 0 };

	if ( gettimeofday ( &tv, &tz ))
		bb_perror_msg_and_die ( "gettimeofday() failed" );

	write_rtc ( tv. tv_sec, utc );
	return 0;
}

#ifdef CONFIG_FEATURE_HWCLOCK_ADJTIME_FHS
# define ADJTIME_PATH "/var/lib/hwclock/adjtime"
#else
# define ADJTIME_PATH "/etc/adjtime"
#endif
static int check_utc(void)
{
	int utc = 0;
	FILE *f = fopen ( ADJTIME_PATH, "r" );

	if ( f ) {
		char buffer [128];

		while ( fgets ( buffer, sizeof( buffer ), f )) {
			int len = bb_strlen ( buffer );

			while ( len && isspace ( buffer [len - 1] ))
				len--;

			buffer [len] = 0;

			if ( strncmp ( buffer, "UTC", 3 ) == 0 ) {
				utc = 1;
				break;
			}
		}
		fclose ( f );
	}
	return utc;
}

#define HWCLOCK_OPT_LOCALTIME	0x01
#define HWCLOCK_OPT_UTC      	0x02
#define HWCLOCK_OPT_SHOW     	0x04
#define HWCLOCK_OPT_HCTOSYS  	0x08
#define HWCLOCK_OPT_SYSTOHC  	0x10

extern int hwclock_main ( int argc, char **argv )
{
	unsigned long opt;
	int utc;

#ifdef CONFIG_FEATURE_HWCLOCK_LONGOPTIONS
static const struct option hwclock_long_options[] = {
		{ "localtime", 0, 0, 'l' },
		{ "utc",       0, 0, 'u' },
		{ "show",      0, 0, 'r' },
		{ "hctosys",   0, 0, 's' },
		{ "systohc",   0, 0, 'w' },
		{ 0,           0, 0, 0 }
	};
	bb_applet_long_options = hwclock_long_options;
#endif

	bb_opt_complementally = "!r~ws:w~rs:s~wr:l~u:u~l";
	opt = bb_getopt_ulflags(argc, argv, "lursw");

	/* If -u or -l wasn't given check if we are using utc */
	if (opt & (HWCLOCK_OPT_UTC | HWCLOCK_OPT_LOCALTIME))
		utc = opt & HWCLOCK_OPT_UTC;
	else
		utc = check_utc();

	if (opt & HWCLOCK_OPT_HCTOSYS) {
		return to_sys_clock ( utc );
	}
	else if (opt & HWCLOCK_OPT_SYSTOHC) {
		return from_sys_clock ( utc );
	} else {
		/* default HWCLOCK_OPT_SHOW */
		return show_clock ( utc );
	}
}