busybox/util-linux/hwclock.c
2006-10-14 02:23:43 +00:00

219 lines
4.5 KiB
C

/* 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 <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 */
#if ENABLE_FEATURE_HWCLOCK_LONG_OPTIONS
# 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 ( "cannot access RTC" );
}
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 */
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 ( "cannot 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 ( "cannot set the RTC time" );
close ( rtc );
}
static int show_clock(int utc)
{
struct tm *ptm;
time_t t;
RESERVE_CONFIG_BUFFER(buffer, 64);
t = read_rtc ( utc );
ptm = localtime ( &t ); /* Sets 'tzname[]' */
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] ));
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 };
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 ) {
RESERVE_CONFIG_BUFFER(buffer, 128);
while ( fgets ( buffer, sizeof( buffer ), f )) {
int len = strlen ( buffer );
while ( len && isspace ( buffer [len - 1] ))
len--;
buffer [len] = 0;
if ( strncmp ( buffer, "UTC", 3 ) == 0 ) {
utc = 1;
break;
}
}
fclose ( f );
RELEASE_CONFIG_BUFFER(buffer);
}
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
int hwclock_main ( int argc, char **argv )
{
unsigned opt;
int utc;
#if ENABLE_FEATURE_HWCLOCK_LONG_OPTIONS
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 }
};
applet_long_options = hwclock_long_options;
#endif
opt_complementary = "?:r--ws:w--rs:s--wr:l--u:u--l";
opt = getopt32(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 );
}
}