busybox/util-linux/hwclock.c

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/* 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 <sys/ioctl.h>
#include <sys/utsname.h>
#include <getopt.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;
};
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#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 */
#if ENABLE_FEATURE_HWCLOCK_LONG_OPTIONS
# ifndef _GNU_SOURCE
# define _GNU_SOURCE
# endif
#endif
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static const char *rtcname;
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static int xopen_rtc(int flags)
{
int rtc;
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if (!rtcname) {
rtc = open("/dev/rtc", flags);
if (rtc >= 0)
return rtc;
rtc = open("/dev/rtc0", flags);
if (rtc >= 0)
return rtc;
rtcname = "/dev/misc/rtc";
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}
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return xopen(rtcname, flags);
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}
static time_t read_rtc(int utc)
{
struct tm tm;
char *oldtz = 0;
time_t t = 0;
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int rtc = xopen_rtc(O_RDONLY);
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memset(&tm, 0, sizeof(struct tm));
if (ioctl(rtc, RTC_RD_TIME, &tm) < 0 )
bb_perror_msg_and_die("cannot read time from RTC");
tm.tm_isdst = -1; /* not known */
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close(rtc);
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if (utc) {
oldtz = getenv("TZ");
setenv("TZ", "UTC 0", 1);
tzset();
}
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t = mktime(&tm);
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if (utc) {
if (oldtz)
setenv("TZ", oldtz, 1);
else
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unsetenv("TZ");
tzset();
}
return t;
}
static void write_rtc(time_t t, int utc)
{
struct tm tm;
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int rtc = xopen_rtc(O_WRONLY);
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tm = *(utc ? gmtime(&t) : localtime(&t));
tm.tm_isdst = 0;
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if (ioctl(rtc, RTC_SET_TIME, &tm) < 0)
bb_perror_msg_and_die("cannot set the RTC time");
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close(rtc);
}
static int show_clock(int utc)
{
struct tm *ptm;
time_t t;
RESERVE_CONFIG_BUFFER(buffer, 64);
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t = read_rtc(utc);
ptm = localtime(&t); /* Sets 'tzname[]' */
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safe_strncpy(buffer, ctime(&t), 64);
if (buffer[0])
buffer[strlen(buffer) - 1] = 0;
//printf("%s %.6f seconds %s\n", buffer, 0.0, utc ? "" : (ptm->tm_isdst ? tzname[1] : tzname[0]));
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printf( "%s %.6f seconds\n", buffer, 0.0);
RELEASE_CONFIG_BUFFER(buffer);
return 0;
}
static int to_sys_clock(int utc)
{
struct timeval tv = { 0, 0 };
const struct timezone tz = { timezone/60 - 60*daylight, 0 };
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tv.tv_sec = read_rtc(utc);
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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 };
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if (gettimeofday(&tv, &tz))
bb_perror_msg_and_die("gettimeofday() failed");
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write_rtc(tv.tv_sec, utc);
return 0;
}
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#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;
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FILE *f = fopen(ADJTIME_PATH, "r");
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if (f) {
RESERVE_CONFIG_BUFFER(buffer, 128);
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while (fgets(buffer, sizeof(buffer), f)) {
int len = strlen(buffer);
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while (len && isspace(buffer[len - 1]))
len--;
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buffer[len] = 0;
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if (strncmp(buffer, "UTC", 3) == 0 ) {
utc = 1;
break;
}
}
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fclose(f);
RELEASE_CONFIG_BUFFER(buffer);
}
return utc;
}
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#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
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#define HWCLOCK_OPT_RTCFILE 0x20
int hwclock_main(int argc, char **argv );
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int hwclock_main(int argc, char **argv )
{
unsigned opt;
int utc;
#if ENABLE_FEATURE_HWCLOCK_LONG_OPTIONS
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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' },
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{ "file", 1, 0, 'f' },
{ 0, 0, 0, 0 }
};
applet_long_options = hwclock_long_options;
#endif
opt_complementary = "?:r--ws:w--rs:s--wr:l--u:u--l";
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opt = getopt32(argc, argv, "lurswf:", &rtcname);
/* If -u or -l wasn't given check if we are using utc */
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if (opt & (HWCLOCK_OPT_UTC | HWCLOCK_OPT_LOCALTIME))
utc = opt & HWCLOCK_OPT_UTC;
else
utc = check_utc();
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if (opt & HWCLOCK_OPT_HCTOSYS) {
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return to_sys_clock(utc);
}
else if (opt & HWCLOCK_OPT_SYSTOHC) {
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return from_sys_clock(utc);
} else {
/* default HWCLOCK_OPT_SHOW */
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return show_clock(utc);
}
}