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>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
#include <sys/utsname.h>
#include <stdlib.h>
#include <unistd.h>
#include <syslog.h>
#include <string.h>
#include <ctype.h>
#include <fcntl.h>
#include <sys/time.h>
#include <time.h>
#include <linux/rtc.h>
#include <sys/ioctl.h>
#include "busybox.h"
#ifdef CONFIG_FEATURE_HWCLOCK_LONGOPTIONS
# ifndef _GNU_SOURCE
# define _GNU_SOURCE
# endif
#endif
#include <getopt.h>
enum OpMode {
SHOW,
SYSTOHC,
HCTOSYS
};
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 )
perror_msg_and_die ( "Could not access RTC" );
}
memset ( &tm, 0, sizeof( struct tm ));
if ( ioctl ( rtc, RTC_RD_TIME, &tm ) < 0 )
perror_msg_and_die ( "Could not 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;
}
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 )
perror_msg_and_die ( "Could not access RTC" );
}
printf ( "1\n" );
tm = *( utc ? gmtime ( &t ) : localtime ( &t ));
tm. tm_isdst = 0;
printf ( "2\n") ;
if ( ioctl ( rtc, RTC_SET_TIME, &tm ) < 0 )
perror_msg_and_die ( "Could not set the RTC time" );
close ( rtc );
}
int show_clock ( int utc )
{
struct tm *ptm;
time_t t;
char buffer [64];
t = read_rtc ( utc );
ptm = localtime ( &t ); /* Sets 'tzname[]' */
safe_strncpy ( buffer, ctime ( &t ), sizeof( buffer ));
if ( buffer [0] )
buffer [xstrlen ( 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 );
return 0;
}
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 ))
perror_msg_and_die ( "settimeofday() failed" );
return 0;
}
int from_sys_clock ( int utc )
{
struct timeval tv = { 0, 0 };
struct timezone tz = { 0, 0 };
if ( gettimeofday ( &tv, &tz ))
perror_msg_and_die ( "gettimeofday() failed" );
write_rtc ( tv. tv_sec, utc );
return 0;
}
int check_utc ( void )
{
int utc = 0;
FILE *f = fopen ( "/etc/adjtime", "r" );
if ( f ) {
char buffer [128];
while ( fgets ( buffer, sizeof( buffer ), f )) {
int len = xstrlen ( buffer );
while ( len && isspace ( buffer [len - 1] ))
len--;
buffer [len] = 0;
if ( strncmp ( buffer, "UTC", 3 ) == 0 ) {
utc = 1;
break;
}
}
fclose ( f );
}
return utc;
}
extern int hwclock_main ( int argc, char **argv )
{
int opt;
enum OpMode mode = SHOW;
int utc = 0;
int utc_arg = 0;
#ifdef CONFIG_FEATURE_HWCLOCK_LONGOPTIONS
struct option long_options[] = {
{ "show", 0, 0, 'r' },
{ "utc", 0, 0, 'u' },
{ "localtime", 0, 0, 'l' },
{ "hctosys", 0, 0, 's' },
{ "systohc", 0, 0, 'w' },
{ 0, 0, 0, 0 }
};
while (( opt = getopt_long ( argc, argv, "rwsul", long_options, 0 )) != EOF ) {
#else
while (( opt = getopt ( argc, argv, "rwsul" )) != EOF ) {
#endif
switch ( opt ) {
case 'r':
mode = SHOW;
break;
case 'w':
mode = SYSTOHC;
break;
case 's':
mode = HCTOSYS;
break;
case 'u':
utc = 1;
utc_arg = 1;
break;
case 'l': // -l is not supported by the normal hwclock (only --localtime)
utc = 0;
utc_arg = 1;
break;
default:
show_usage();
break;
}
}
if ( !utc_arg )
utc = check_utc ( );
switch ( mode ) {
case SYSTOHC:
return from_sys_clock ( utc );
case HCTOSYS:
return to_sys_clock ( utc );
case SHOW:
default:
return show_clock ( utc );
}
}