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
|
/* vi: set sw=4 ts=4: */
/*
* Mini hwclock implementation for busybox
*
* Copyright (C) 2002 Robert Griebl <griebl@gmx.de>
*
* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
*/
#include "libbb.h"
/* After libbb.h, since it needs sys/types.h on some systems */
#include <sys/utsname.h>
#include "rtc_.h"
#if ENABLE_FEATURE_HWCLOCK_LONG_OPTIONS
# ifndef _GNU_SOURCE
# define _GNU_SOURCE
# endif
#endif
/* diff code is disabled: it's not sys/hw clock diff, it's some useless
* "time between hwclock was started and we saw CMOS tick" quantity.
* It's useless since hwclock is started at a random moment,
* thus the quantity is also random, useless. Showing 0.000000 does not
* deprive us from any useful info.
*
* SHOW_HWCLOCK_DIFF code in this file shows the difference between system
* and hw clock. It is useful, but not compatible with standard hwclock.
* Thus disabled.
*/
#define SHOW_HWCLOCK_DIFF 0
#if !SHOW_HWCLOCK_DIFF
# define read_rtc(pp_rtcname, sys_tv, utc) read_rtc(pp_rtcname, utc)
#endif
static time_t read_rtc(const char **pp_rtcname, struct timeval *sys_tv, int utc)
{
struct tm tm_time;
int fd;
fd = rtc_xopen(pp_rtcname, O_RDONLY);
rtc_read_tm(&tm_time, fd);
#if SHOW_HWCLOCK_DIFF
{
int before = tm_time.tm_sec;
while (1) {
rtc_read_tm(&tm_time, fd);
gettimeofday(sys_tv, NULL);
if (before != tm_time.tm_sec)
break;
}
}
#endif
if (ENABLE_FEATURE_CLEAN_UP)
close(fd);
return rtc_tm2time(&tm_time, utc);
}
static void show_clock(const char **pp_rtcname, int utc)
{
#if SHOW_HWCLOCK_DIFF
struct timeval sys_tv;
#endif
time_t t;
char *cp;
t = read_rtc(pp_rtcname, &sys_tv, utc);
cp = ctime(&t);
strchrnul(cp, '\n')[0] = '\0';
#if !SHOW_HWCLOCK_DIFF
printf("%s 0.000000 seconds\n", cp);
#else
{
long diff = sys_tv.tv_sec - t;
if (diff < 0 /*&& tv.tv_usec != 0*/) {
/* Why? */
/* diff >= 0 is ok: diff < 0, can't just use tv.tv_usec: */
/* 45.520820 43.520820 */
/* - 44.000000 - 45.000000 */
/* = 1.520820 = -1.479180, not -2.520820! */
diff++;
/* should be 1000000 - tv.tv_usec, but then we must check tv.tv_usec != 0 */
sys_tv.tv_usec = 999999 - sys_tv.tv_usec;
}
printf("%s %ld.%06lu seconds\n", cp, diff, (unsigned long)sys_tv.tv_usec);
}
#endif
}
static void to_sys_clock(const char **pp_rtcname, int utc)
{
struct timeval tv;
struct timezone tz;
tz.tz_minuteswest = timezone/60 - 60*daylight;
tz.tz_dsttime = 0;
tv.tv_sec = read_rtc(pp_rtcname, NULL, utc);
tv.tv_usec = 0;
if (settimeofday(&tv, &tz))
bb_perror_msg_and_die("settimeofday");
}
static void from_sys_clock(const char **pp_rtcname, int utc)
{
#define TWEAK_USEC 200
struct tm tm_time;
struct timeval tv;
unsigned adj = TWEAK_USEC;
int rtc = rtc_xopen(pp_rtcname, O_WRONLY);
/* Try to catch the moment when whole second is close */
while (1) {
unsigned rem_usec;
time_t t;
gettimeofday(&tv, NULL);
t = tv.tv_sec;
rem_usec = 1000000 - tv.tv_usec;
if (rem_usec < 1024) {
/* Less than 1ms to next second. Good enough */
small_rem:
t++;
}
/* Prepare tm */
if (utc)
gmtime_r(&t, &tm_time); /* may read /etc/xxx (it takes time) */
else
localtime_r(&t, &tm_time); /* same */
tm_time.tm_isdst = 0;
/* gmtime/localtime took some time, re-get cur time */
gettimeofday(&tv, NULL);
if (tv.tv_sec < t /* may happen if rem_usec was < 1024 */
|| (tv.tv_sec == t && tv.tv_usec < 1024)
) {
/* We are not too far into next second. Good. */
break;
}
adj += 32; /* 2^(10-5) = 2^5 = 32 iterations max */
if (adj >= 1024) {
/* Give up trying to sync */
break;
}
/* Try to sync up by sleeping */
rem_usec = 1000000 - tv.tv_usec;
if (rem_usec < 1024) {
goto small_rem; /* already close, don't sleep */
}
/* Need to sleep.
* Note that small adj on slow processors can make us
* to always overshoot tv.tv_usec < 1024 check on next
* iteration. That's why adj is increased on each iteration.
* This also allows it to be reused as a loop limiter.
*/
usleep(rem_usec - adj);
}
xioctl(rtc, RTC_SET_TIME, &tm_time);
/* Debug aid to find "good" TWEAK_USEC.
* Look for a value which makes tv_usec close to 999999 or 0.
* for 2.20GHz Intel Core 2: TWEAK_USEC ~= 200
*/
//bb_error_msg("tv.tv_usec:%d adj:%d", (int)tv.tv_usec, adj);
if (ENABLE_FEATURE_CLEAN_UP)
close(rtc);
}
#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
#define HWCLOCK_OPT_RTCFILE 0x20
int hwclock_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int hwclock_main(int argc UNUSED_PARAM, char **argv)
{
const char *rtcname = NULL;
unsigned opt;
int utc;
#if ENABLE_FEATURE_HWCLOCK_LONG_OPTIONS
static const char hwclock_longopts[] ALIGN1 =
"localtime\0" No_argument "l"
"utc\0" No_argument "u"
"show\0" No_argument "r"
"hctosys\0" No_argument "s"
"systohc\0" No_argument "w"
"file\0" Required_argument "f"
;
applet_long_options = hwclock_longopts;
#endif
opt_complementary = "r--ws:w--rs:s--wr:l--u:u--l";
opt = getopt32(argv, "lurswf:", &rtcname);
/* 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 = rtc_adjtime_is_utc();
if (opt & HWCLOCK_OPT_HCTOSYS)
to_sys_clock(&rtcname, utc);
else if (opt & HWCLOCK_OPT_SYSTOHC)
from_sys_clock(&rtcname, utc);
else
/* default HWCLOCK_OPT_SHOW */
show_clock(&rtcname, utc);
return 0;
}
|
