Diff of /trunk/mkinitrd-magellan/busybox/util-linux/hwclock.c

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	revision 983 by niro, Fri Apr 24 18:33:46 2009 UTC	revision 984 by niro, Sun May 30 11:32:42 2010 UTC
#	Line 7	Line 7
7	* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.	* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
8	*/	*/
9
	#include <sys/utsname.h>
10	#include "libbb.h"	#include "libbb.h"
11		/* After libbb.h, since it needs sys/types.h on some systems */
12		#include <sys/utsname.h>
13	#include "rtc_.h"	#include "rtc_.h"
14
15	#if ENABLE_FEATURE_HWCLOCK_LONG_OPTIONS	#if ENABLE_FEATURE_HWCLOCK_LONG_OPTIONS
#	Line 17	Line 18
18	# endif	# endif
19	#endif	#endif
20
	static const char *rtcname;
21
22	static time_t read_rtc(int utc)	/* diff code is disabled: it's not sys/hw clock diff, it's some useless
23		* "time between hwclock was started and we saw CMOS tick" quantity.
24		* It's useless since hwclock is started at a random moment,
25		* thus the quantity is also random, useless. Showing 0.000000 does not
26		* deprive us from any useful info.
27		*
28		* SHOW_HWCLOCK_DIFF code in this file shows the difference between system
29		* and hw clock. It is useful, but not compatible with standard hwclock.
30		* Thus disabled.
31		*/
32		#define SHOW_HWCLOCK_DIFF 0
33
34
35		#if !SHOW_HWCLOCK_DIFF
36		# define read_rtc(pp_rtcname, sys_tv, utc) read_rtc(pp_rtcname, utc)
37		#endif
38		static time_t read_rtc(const char **pp_rtcname, struct timeval *sys_tv, int utc)
39	{	{
40	time_t ret;	struct tm tm_time;
41	int fd;	int fd;
42
43	fd = rtc_xopen(&rtcname, O_RDONLY);	fd = rtc_xopen(pp_rtcname, O_RDONLY);
	ret = rtc_read_time(fd, utc);
	close(fd);
	return ret;
	}
44
45	static void write_rtc(time_t t, int utc)	rtc_read_tm(&tm_time, fd);
	{
	struct tm tm;
	int rtc = rtc_xopen(&rtcname, O_WRONLY);
46
47	tm = *(utc ? gmtime(&t) : localtime(&t));	#if SHOW_HWCLOCK_DIFF
48	tm.tm_isdst = 0;	{
49		int before = tm_time.tm_sec;
50		while (1) {
51		rtc_read_tm(&tm_time, fd);
52		gettimeofday(sys_tv, NULL);
53		if (before != tm_time.tm_sec)
54		break;
55		}
56		}
57		#endif
58
59	xioctl(rtc, RTC_SET_TIME, &tm);	if (ENABLE_FEATURE_CLEAN_UP)
60		close(fd);
61
62	close(rtc);	return rtc_tm2time(&tm_time, utc);
63	}	}
64
65	static void show_clock(int utc)	static void show_clock(const char **pp_rtcname, int utc)
66	{	{
67	//struct tm *ptm;	#if SHOW_HWCLOCK_DIFF
68		struct timeval sys_tv;
69		#endif
70	time_t t;	time_t t;
71	char *cp;	char *cp;
72
73	t = read_rtc(utc);	t = read_rtc(pp_rtcname, &sys_tv, utc);
	//ptm = localtime(&t);  /* Sets 'tzname[]' */
74	cp = ctime(&t);	cp = ctime(&t);
75	if (cp[0])	strchrnul(cp, '\n')[0] = '\0';
76	cp[strlen(cp) - 1] = '\0';	#if !SHOW_HWCLOCK_DIFF
	//printf("%s  %.6f seconds %s\n", cp, 0.0, utc ? "" : (ptm->tm_isdst ? tzname[1] : tzname[0]));
77	printf("%s  0.000000 seconds\n", cp);	printf("%s  0.000000 seconds\n", cp);
78		#else
79		{
80		long diff = sys_tv.tv_sec - t;
81		if (diff < 0 /*&& tv.tv_usec != 0*/) {
82		/* Why? */
83		/* diff >= 0 is ok:   diff < 0, can't just use tv.tv_usec: */
84		/*   45.520820          43.520820 */
85		/* - 44.000000        - 45.000000 */
86		/* =  1.520820        = -1.479180, not -2.520820! */
87		diff++;
88		/* should be 1000000 - tv.tv_usec, but then we must check tv.tv_usec != 0 */
89		sys_tv.tv_usec = 999999 - sys_tv.tv_usec;
90		}
91		printf("%s  %ld.%06lu seconds\n", cp, diff, (unsigned long)sys_tv.tv_usec);
92		}
93		#endif
94	}	}
95
96	static void to_sys_clock(int utc)	static void to_sys_clock(const char **pp_rtcname, int utc)
97	{	{
98	struct timeval tv;	struct timeval tv;
99	const struct timezone tz = { timezone/60 - 60*daylight, 0 };	struct timezone tz;
100
101		tz.tz_minuteswest = timezone/60 - 60*daylight;
102		tz.tz_dsttime = 0;
103
104	tv.tv_sec = read_rtc(utc);	tv.tv_sec = read_rtc(pp_rtcname, NULL, utc);
105	tv.tv_usec = 0;	tv.tv_usec = 0;
106	if (settimeofday(&tv, &tz))	if (settimeofday(&tv, &tz))
107	bb_perror_msg_and_die("settimeofday() failed");	bb_perror_msg_and_die("settimeofday");
108	}	}
109
110	static void from_sys_clock(int utc)	static void from_sys_clock(const char **pp_rtcname, int utc)
111	{	{
112		#define TWEAK_USEC 200
113		struct tm tm_time;
114	struct timeval tv;	struct timeval tv;
115		unsigned adj = TWEAK_USEC;
116		int rtc = rtc_xopen(pp_rtcname, O_WRONLY);
117
118		/* Try to catch the moment when whole second is close */
119		while (1) {
120		unsigned rem_usec;
121		time_t t;
122
123		gettimeofday(&tv, NULL);
124
125		t = tv.tv_sec;
126		rem_usec = 1000000 - tv.tv_usec;
127		if (rem_usec < 1024) {
128		/* Less than 1ms to next second. Good enough */
129		small_rem:
130		t++;
131		}
132
133		/* Prepare tm */
134		if (utc)
135		gmtime_r(&t, &tm_time); /* may read /etc/xxx (it takes time) */
136		else
137		localtime_r(&t, &tm_time); /* same */
138		tm_time.tm_isdst = 0;
139
140		/* gmtime/localtime took some time, re-get cur time */
141		gettimeofday(&tv, NULL);
142
143		if (tv.tv_sec < t /* may happen if rem_usec was < 1024 */
144		|| (tv.tv_sec == t && tv.tv_usec < 1024)
145		) {
146		/* We are not too far into next second. Good. */
147		break;
148		}
149		adj += 32; /* 2^(10-5) = 2^5 = 32 iterations max */
150		if (adj >= 1024) {
151		/* Give up trying to sync */
152		break;
153		}
154
155		/* Try to sync up by sleeping */
156		rem_usec = 1000000 - tv.tv_usec;
157		if (rem_usec < 1024) {
158		goto small_rem; /* already close, don't sleep */
159		}
160		/* Need to sleep.
161		* Note that small adj on slow processors can make us
162		* to always overshoot tv.tv_usec < 1024 check on next
163		* iteration. That's why adj is increased on each iteration.
164		* This also allows it to be reused as a loop limiter.
165		*/
166		usleep(rem_usec - adj);
167		}
168
169		xioctl(rtc, RTC_SET_TIME, &tm_time);
170
171		/* Debug aid to find "good" TWEAK_USEC.
172		* Look for a value which makes tv_usec close to 999999 or 0.
173		* for 2.20GHz Intel Core 2: TWEAK_USEC ~= 200
174		*/
175		//bb_error_msg("tv.tv_usec:%d adj:%d", (int)tv.tv_usec, adj);
176
177	gettimeofday(&tv, NULL);	if (ENABLE_FEATURE_CLEAN_UP)
178	//if (gettimeofday(&tv, NULL))	close(rtc);
	// bb_perror_msg_and_die("gettimeofday() failed");
	write_rtc(tv.tv_sec, utc);
179	}	}
180
181	#define HWCLOCK_OPT_LOCALTIME   0x01	#define HWCLOCK_OPT_LOCALTIME   0x01
#	Line 92  static void from_sys_clock(int utc)	Line 188  static void from_sys_clock(int utc)
188	int hwclock_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;	int hwclock_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
189	int hwclock_main(int argc UNUSED_PARAM, char **argv)	int hwclock_main(int argc UNUSED_PARAM, char **argv)
190	{	{
191		const char *rtcname = NULL;
192	unsigned opt;	unsigned opt;
193	int utc;	int utc;
194
#	Line 116  int hwclock_main(int argc UNUSED_PARAM,	Line 213  int hwclock_main(int argc UNUSED_PARAM,
213	utc = rtc_adjtime_is_utc();	utc = rtc_adjtime_is_utc();
214
215	if (opt & HWCLOCK_OPT_HCTOSYS)	if (opt & HWCLOCK_OPT_HCTOSYS)
216	to_sys_clock(utc);	to_sys_clock(&rtcname, utc);
217	else if (opt & HWCLOCK_OPT_SYSTOHC)	else if (opt & HWCLOCK_OPT_SYSTOHC)
218	from_sys_clock(utc);	from_sys_clock(&rtcname, utc);
219	else	else
220	/* default HWCLOCK_OPT_SHOW */	/* default HWCLOCK_OPT_SHOW */
221	show_clock(utc);	show_clock(&rtcname, utc);
222
223	return 0;	return 0;
224	}	}

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