source: MondoRescue/trunk/mindi-busybox/util-linux/hwclock.c@ 956

/* 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 ( "Could not access RTC" );
    }
    memset ( &tm, 0, sizeof( struct tm ));
    if ( ioctl ( rtc, RTC_RD_TIME, &tm ) < 0 )
        bb_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;
}

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 ( "Could not 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 ( "Could not 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 long 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 }
    };
    bb_applet_long_options = hwclock_long_options;
#endif

    bb_opt_complementally = "?:r--ws:w--rs:s--wr:l--u:u--l";
    opt = bb_getopt_ulflags(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 );
    }
}