hush/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/utsname.h>
#include <getopt.h>
#include "libbb.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));
xioctl(rtc, RTC_RD_TIME, &tm);
tm.tm_isdst = -1; /* not known */
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close(rtc);
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if (utc) {
oldtz = getenv("TZ");
putenv((char*)"TZ=UTC0");
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tzset();
}
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t = mktime(&tm);
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if (utc) {
unsetenv("TZ");
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if (oldtz)
putenv(oldtz - 3);
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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;
xioctl(rtc, RTC_SET_TIME, &tm);
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close(rtc);
}
static void show_clock(int utc)
{
//struct tm *ptm;
time_t t;
char *cp;
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t = read_rtc(utc);
//ptm = localtime(&t); /* Sets 'tzname[]' */
cp = ctime(&t);
if (cp[0])
cp[strlen(cp) - 1] = '\0';
//printf("%s %.6f seconds %s\n", cp, 0.0, utc ? "" : (ptm->tm_isdst ? tzname[1] : tzname[0]));
printf("%s 0.000000 seconds\n", cp);
}
static void to_sys_clock(int utc)
{
struct timeval tv;
const struct timezone tz = { timezone/60 - 60*daylight, 0 };
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tv.tv_sec = read_rtc(utc);
tv.tv_usec = 0;
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if (settimeofday(&tv, &tz))
bb_perror_msg_and_die("settimeofday() failed");
}
static void from_sys_clock(int utc)
{
struct timeval tv;
gettimeofday(&tv, NULL);
//if (gettimeofday(&tv, NULL))
// bb_perror_msg_and_die("gettimeofday() failed");
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write_rtc(tv.tv_sec, utc);
}
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#if ENABLE_FEATURE_HWCLOCK_ADJTIME_FHS
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# 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;
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);
int hwclock_main(int argc, char **argv)
{
unsigned opt;
int utc;
#if ENABLE_FEATURE_HWCLOCK_LONG_OPTIONS
static const char hwclock_longopts[] ALIGN1 =
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"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"
;
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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 */
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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) {
to_sys_clock(utc);
return 0;
}
if (opt & HWCLOCK_OPT_SYSTOHC) {
from_sys_clock(utc);
return 0;
}
/* default HWCLOCK_OPT_SHOW */
show_clock(utc);
return 0;
}