Initial checkin of a very primitive hwclock replacement

1 files changed, 229 insertions, 0 deletions

diff --git a/util-linux/hwclock.c b/util-linux/hwclock.c
new file mode 100644
index 0000000..88222e6
--- /dev/null
+++ b/util-linux/hwclock.c
@@ -0,0 +1,229 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * really dumb hwclock implementation for busybox
+ * Copyright (C) 2002 Robert Griebl <griebl@gmx.de>
+ *
+ */
+
+
+#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 );	
+	}	
+}
+
+