ntp_util.c   [plain text]

/*
 * ntp_util.c - stuff I didn't have any other place for
 */

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif

#include "ntpd.h"
#include "ntp_io.h"
#include "ntp_unixtime.h"
#include "ntp_filegen.h"
#include "ntp_if.h"
#include "ntp_stdlib.h"

#include <stdio.h>
#include <ctype.h>
#include <sys/types.h>
#ifdef HAVE_SYS_IOCTL_H
# include <sys/ioctl.h>
#endif

#ifdef HAVE_IEEEFP_H
# include <ieeefp.h>
#endif
#ifdef HAVE_MATH_H
# include <math.h>
#endif

#ifdef  DOSYNCTODR
# if !defined(VMS)
#  include <sys/resource.h>
# endif /* VMS */
#endif

#if defined(VMS)
# include <descrip.h>
#endif /* VMS */

#include <vproc.h>
#include <sys/mman.h>		/* mmap */
#include <signal.h>

/*
 * This contains odds and ends.  Right now the only thing you'll find
 * in here is the hourly stats printer and some code to support
 * rereading the keys file, but I may eventually put other things in
 * here such as code to do something with the leap bits.
 */
/*
 * Name of the keys file
 */
static	char *key_file_name;

/*
 * The name of the drift_comp file and the temporary.
 */
static	char *stats_drift_file;
static  int drift_exists;
static	char *stats_temp_file;
int stats_write_period = 3600;	/* # of seconds between writes. */
double stats_write_tolerance = 0;
static double prev_drift_comp = 99999.;

/*
 * Statistics file stuff
 */
#ifndef NTP_VAR
# ifndef SYS_WINNT
#  define NTP_VAR "/var/NTP/"		/* NOTE the trailing '/' */
# else
#  define NTP_VAR "c:\\var\\ntp\\"		/* NOTE the trailing '\\' */
# endif /* SYS_WINNT */
#endif

#ifndef MAXPATHLEN
# define MAXPATHLEN 256
#endif

static	char statsdir[MAXPATHLEN] = NTP_VAR;

static FILEGEN peerstats;
static FILEGEN loopstats;
static FILEGEN clockstats;
static FILEGEN rawstats;
static FILEGEN sysstats;
#ifdef DEBUG_TIMING
static FILEGEN timingstats;
#endif
#ifdef OPENSSL
static FILEGEN cryptostats;
#endif /* OPENSSL */

/* derived from PM tool getsleep.c */
#include <mach/mach_port.h>
#include <mach/mach_interface.h>
#include <mach/mach_init.h>

#include <IOKit/pwr_mgt/IOPMLib.h>
#include <IOKit/pwr_mgt/IOPM.h>

static io_connect_t getFB(void) {
	static io_connect_t fb;
	
	if (!fb) {
		fb = IOPMFindPowerManagement(kIOMasterPortDefault);
	}
	return fb;
}

static unsigned long energy_saving(void) {
	IOReturn err;
	unsigned long min = 99;
	io_connect_t fb = getFB();

	if (fb) {
		err = IOPMGetAggressiveness( fb, kPMMinutesToSleep, &min);
		if (err == kIOReturnSuccess) {
			if (min > 0) {
				return min;
			} else {
				err = IOPMGetAggressiveness( fb, kPMMinutesToSpinDown, &min);
				if (err == kIOReturnSuccess) {
					return min;
				}
			}
		}
	}
	return 0;
}
/*
 * This controls whether stats are written to the fileset. Provided
 * so that ntpdc can turn off stats when the file system fills up. 
 */
int stats_control;

/*
 * Initial frequency offset later passed to the loopfilter.
 */
double	old_drift;

/*
 * init_util - initialize the utilities
 */
void
init_util(void)
{
	stats_drift_file = 0;
	stats_temp_file = 0;
	key_file_name = 0;

	filegen_register(&statsdir[0], "peerstats", &peerstats);

	filegen_register(&statsdir[0], "loopstats", &loopstats);

	filegen_register(&statsdir[0], "clockstats", &clockstats);

	filegen_register(&statsdir[0], "rawstats", &rawstats);

	filegen_register(&statsdir[0], "sysstats", &sysstats);

#ifdef OPENSSL
	filegen_register(&statsdir[0], "cryptostats", &cryptostats);
#endif /* OPENSSL */

#ifdef DEBUG_TIMING
	filegen_register(&statsdir[0], "timingstats", &timingstats);
#endif
}

int
save_drift_file(
	)
{
	FILE *fp;
	int rc = true;
	vproc_transaction_t vt;
	static off_t stats_size = 0;
	sigset_t sigterm, oset;

	sigemptyset(&sigterm);
	sigaddset(&sigterm, SIGTERM);
	sigprocmask(SIG_BLOCK, &sigterm, &oset);
	vt = vproc_transaction_begin(NULL);
	if (stats_drift_file != 0 && (!drift_exists || !energy_saving())) {
		if ((fp = fopen(stats_temp_file, "w")) == NULL) {
			msyslog(LOG_ERR, "can't open %s: %m",
			    stats_temp_file);
			rc = false;
			goto done;
		}
		stats_size = fprintf(fp, "%.3f\n", drift_comp * 1e6);
		(void)fclose(fp);
		/* atomic */
#ifdef SYS_WINNT
		(void) _unlink(stats_drift_file); /* rename semantics differ under NT */
#endif /* SYS_WINNT */

#ifndef NO_RENAME
		(void) rename(stats_temp_file, stats_drift_file);
#else
		/* we have no rename NFS of ftp in use*/
		if ((fp = fopen(stats_drift_file, "w")) == NULL) {
			msyslog(LOG_ERR, "can't open %s: %m",
			    stats_drift_file);
			rc = false;
		}

#endif
	        drift_exists++;
#if defined(VMS)
		/* PURGE */
		{
			$DESCRIPTOR(oldvers,";-1");
			struct dsc$descriptor driftdsc = {
				strlen(stats_drift_file),0,0,stats_drift_file };

			while(lib$delete_file(&oldvers,&driftdsc) & 1) ;
		}
#endif
	} else {
		/* use mmap */
		static void *mmap_addr;
		if (mmap_addr == 0) {
			int fd = open(stats_drift_file, O_RDWR);
			if (fd >= 0) {
				mmap_addr = mmap(0, getpagesize(), PROT_READ|PROT_WRITE, MAP_FILE|MAP_SHARED, fd, 0);
				if (mmap_addr == MAP_FAILED) {
					msyslog(LOG_ERR, "can't mmap %s: %m", stats_drift_file);
					mmap_addr = 0;
					rc = false;
				}
				close(fd);
			} else {
				msyslog(LOG_ERR, "can't open %s: %m", stats_drift_file);
				rc = false;
			}
		} else {
			off_t n = snprintf(mmap_addr, getpagesize(), "%.3f\n", drift_comp * 1e6);
			if (n != stats_size) {
				truncate(stats_drift_file, n);
				stats_size = n;
			}
		}
	}
done:
	vproc_transaction_end(NULL, vt);
	sigprocmask(SIG_SETMASK, &oset, NULL);
	return rc;
}

/*
 * hourly_stats - print some interesting stats
 */
void
write_stats(void)
{
#ifdef DOSYNCTODR
	struct timeval tv;
#if !defined(VMS)
	int prio_set;
#endif
#ifdef HAVE_GETCLOCK
        struct timespec ts;
#endif
	int o_prio;

	/*
	 * Sometimes having a Sun can be a drag.
	 *
	 * The kernel variable dosynctodr controls whether the system's
	 * soft clock is kept in sync with the battery clock. If it
	 * is zero, then the soft clock is not synced, and the battery
	 * clock is simply left to rot. That means that when the system
	 * reboots, the battery clock (which has probably gone wacky)
	 * sets the soft clock. That means ntpd starts off with a very
	 * confused idea of what time it is. It then takes a large
	 * amount of time to figure out just how wacky the battery clock
	 * has made things drift, etc, etc. The solution is to make the
	 * battery clock sync up to system time. The way to do THAT is
	 * to simply set the time of day to the current time of day, but
	 * as quickly as possible. This may, or may not be a sensible
	 * thing to do.
	 *
	 * CAVEAT: settimeofday() steps the sun clock by about 800 us,
	 *         so setting DOSYNCTODR seems a bad idea in the
	 *         case of us resolution
	 */

#if !defined(VMS)
	/* (prr) getpriority returns -1 on error, but -1 is also a valid
	 * return value (!), so instead we have to zero errno before the
	 * call and check it for non-zero afterwards.
	 */
	errno = 0;
	prio_set = 0;
	o_prio = getpriority(PRIO_PROCESS,0); /* Save setting */

	/*
	 * (prr) if getpriority succeeded, call setpriority to raise
	 * scheduling priority as high as possible.  If that succeeds
	 * as well, set the prio_set flag so we remember to reset
	 * priority to its previous value below.  Note that on Solaris
	 * 2.6 (and beyond?), both getpriority and setpriority will fail
	 * with ESRCH, because sched_setscheduler (called from main) put
	 * us in the real-time scheduling class which setpriority
	 * doesn't know about. Being in the real-time class is better
	 * than anything setpriority can do, anyhow, so this error is
	 * silently ignored.
	 */
	if ((errno == 0) && (setpriority(PRIO_PROCESS,0,-20) == 0))
		prio_set = 1;	/* overdrive */
#endif /* VMS */
#ifdef HAVE_GETCLOCK
        (void) getclock(TIMEOFDAY, &ts);
        tv.tv_sec = ts.tv_sec;
        tv.tv_usec = ts.tv_nsec / 1000;
#else /*  not HAVE_GETCLOCK */
	GETTIMEOFDAY(&tv,(struct timezone *)NULL);
#endif /* not HAVE_GETCLOCK */
	if (ntp_set_tod(&tv,(struct timezone *)NULL) != 0) {
		msyslog(LOG_ERR, "can't sync battery time: %m");
	}
#if !defined(VMS)
	if (prio_set)
		setpriority(PRIO_PROCESS, 0, o_prio); /* downshift */
#endif /* VMS */
#endif /* DOSYNCTODR */

	NLOG(NLOG_SYSSTATIST)
		msyslog(LOG_INFO,
		    "offset %.6f sec freq %.3f ppm error %.6f poll %d",
		    last_offset, drift_comp * 1e6, sys_jitter,
		    sys_poll);

	
	record_sys_stats();
	if ((u_long)(fabs(prev_drift_comp - drift_comp) * 1e9) <=
	    (u_long)(fabs(stats_write_tolerance * drift_comp) * 1e9)) {
	     return;
	}
	if (save_drift_file())
		prev_drift_comp = drift_comp;
}


/*
 * stats_config - configure the stats operation
 */
void
stats_config(
	int item,
	const char *invalue	/* only one type so far */
	)
{
	FILE *fp;
	const char *value;
	int len;

	/*
	 * Expand environment strings under Windows NT, since the
	 * command interpreter doesn't do this, the program must.
	 */
#ifdef SYS_WINNT
	char newvalue[MAX_PATH], parameter[MAX_PATH];

	if (!ExpandEnvironmentStrings(invalue, newvalue, MAX_PATH)) {
 		switch(item) {
		    case STATS_FREQ_FILE:
			strcpy(parameter,"STATS_FREQ_FILE");
			break;
		    case STATS_STATSDIR:
			strcpy(parameter,"STATS_STATSDIR");
			break;
		    case STATS_PID_FILE:
			strcpy(parameter,"STATS_PID_FILE");
			break;
		    default:
			strcpy(parameter,"UNKNOWN");
			break;
		}
		value = invalue;

		msyslog(LOG_ERR,
		    "ExpandEnvironmentStrings(%s) failed: %m\n", parameter);
	} else {
		value = newvalue;
	}
#else    
	value = invalue;
#endif /* SYS_WINNT */

	switch(item) {
	    case STATS_FREQ_FILE:
		if (stats_drift_file != 0) {
			(void) free(stats_drift_file);
			(void) free(stats_temp_file);
			stats_drift_file = 0;
			stats_temp_file = 0;
		}

		if (value == 0 || (len = strlen(value)) == 0)
		    break;

		stats_drift_file = (char*)emalloc((u_int)(len + 1));
#if !defined(VMS)
		stats_temp_file = (char*)emalloc((u_int)(len +
		    sizeof(".TEMP")));
#else
		stats_temp_file = (char*)emalloc((u_int)(len +
		    sizeof("-TEMP")));
#endif /* VMS */
		memmove(stats_drift_file, value, (unsigned)(len+1));
		memmove(stats_temp_file, value, (unsigned)len);
#if !defined(VMS)
		memmove(stats_temp_file + len, ".TEMP",
		    sizeof(".TEMP"));
#else
		memmove(stats_temp_file + len, "-TEMP",
		    sizeof("-TEMP"));
#endif /* VMS */

		/*
		 * Open drift file and read frequency. If the file is
		 * missing or contains errors, tell the loop to reset.
		 */
		if ((fp = fopen(stats_drift_file, "r")) == NULL) {
			old_drift = 1e9;
			break;
		}
		if (fscanf(fp, "%lf", &old_drift) != 1) {
			msyslog(LOG_ERR, "Frequency format error in %s", 
			    stats_drift_file);
			old_drift = 1e9;
			fclose(fp);
			break;
		}
		fclose(fp);
		drift_exists++;
		prev_drift_comp = old_drift / 1e6;
		msyslog(LOG_INFO,
		    "frequency initialized %.3f PPM from %s",
			old_drift, stats_drift_file);
		break;
	
	    case STATS_STATSDIR:
		if (strlen(value) >= sizeof(statsdir)) {
			msyslog(LOG_ERR,
			    "value for statsdir too long (>%d, sigh)",
			    (int)sizeof(statsdir)-1);
		} else {
			l_fp now;

			get_systime(&now);
			strcpy(statsdir,value);
			if(peerstats.prefix == &statsdir[0] &&
			    peerstats.fp != NULL) {
				fclose(peerstats.fp);
				peerstats.fp = NULL;
				filegen_setup(&peerstats, now.l_ui);
			}
			if(loopstats.prefix == &statsdir[0] &&
			    loopstats.fp != NULL) {
				fclose(loopstats.fp);
				loopstats.fp = NULL;
				filegen_setup(&loopstats, now.l_ui);
			}
			if(clockstats.prefix == &statsdir[0] &&
			    clockstats.fp != NULL) {
				fclose(clockstats.fp);
				clockstats.fp = NULL;
				filegen_setup(&clockstats, now.l_ui);
			}
			if(rawstats.prefix == &statsdir[0] &&
			    rawstats.fp != NULL) {
				fclose(rawstats.fp);
				rawstats.fp = NULL;
				filegen_setup(&rawstats, now.l_ui);
			}
			if(sysstats.prefix == &statsdir[0] &&
			    sysstats.fp != NULL) {
				fclose(sysstats.fp);
				sysstats.fp = NULL;
				filegen_setup(&sysstats, now.l_ui);
			}
#ifdef OPENSSL
			if(cryptostats.prefix == &statsdir[0] &&
			    cryptostats.fp != NULL) {
				fclose(cryptostats.fp);
				cryptostats.fp = NULL;
				filegen_setup(&cryptostats, now.l_ui);
			}
#endif /* OPENSSL */
		}
		break;

	    case STATS_PID_FILE:
		if ((fp = fopen(value, "w")) == NULL) {
			msyslog(LOG_ERR, "Can't open %s: %m", value);
			break;
		}
		fprintf(fp, "%d", (int) getpid());
		fclose(fp);;
		break;

	    default:
		/* oh well */
		break;
	}
}

/*
 * record_peer_stats - write peer statistics to file
 *
 * file format:
 * day (mjd)
 * time (s past UTC midnight)
 * peer (ip address)
 * peer status word (hex)
 * peer offset (s)
 * peer delay (s)
 * peer error bound (s)
 * peer error (s)
*/
void
record_peer_stats(
	struct sockaddr_storage *addr,
	int	status,
	double	offset,
	double	delay,
	double	dispersion,
	double	skew
	)
{
	l_fp	now;
	u_long	day;

	if (!stats_control)
		return;

	get_systime(&now);
	filegen_setup(&peerstats, now.l_ui);
	day = now.l_ui / 86400 + MJD_1900;
	now.l_ui %= 86400;
	if (peerstats.fp != NULL) {
		fprintf(peerstats.fp,
		    "%lu %s %s %x %.9f %.9f %.9f %.9f\n",
		    day, ulfptoa(&now, 3), stoa(addr), status, offset,
		    delay, dispersion, skew);
		fflush(peerstats.fp);
	}
}

/*
 * record_loop_stats - write loop filter statistics to file
 *
 * file format:
 * day (mjd)
 * time (s past midnight)
 * offset (s)
 * frequency (approx ppm)
 * time constant (log base 2)
 */
void
record_loop_stats(
	double	offset,
	double	freq,
	double	jitter,
	double	stability,
	int spoll
	)
{
	l_fp	now;
	u_long	day;

	if (!stats_control)
		return;

	get_systime(&now);
	filegen_setup(&loopstats, now.l_ui);
	day = now.l_ui / 86400 + MJD_1900;
	now.l_ui %= 86400;
	if (loopstats.fp != NULL) {
		fprintf(loopstats.fp, "%lu %s %.9f %.3f %.9f %.6f %d\n",
		    day, ulfptoa(&now, 3), offset, freq * 1e6, jitter,
		    stability * 1e6, spoll);
		fflush(loopstats.fp);
	}
}

/*
 * record_clock_stats - write clock statistics to file
 *
 * file format:
 * day (mjd)
 * time (s past midnight)
 * peer (ip address)
 * text message
 */
void
record_clock_stats(
	struct sockaddr_storage *addr,
	const char *text
	)
{
	l_fp	now;
	u_long	day;

	if (!stats_control)
		return;

	get_systime(&now);
	filegen_setup(&clockstats, now.l_ui);
	day = now.l_ui / 86400 + MJD_1900;
	now.l_ui %= 86400;
	if (clockstats.fp != NULL) {
		fprintf(clockstats.fp, "%lu %s %s %s\n",
		    day, ulfptoa(&now, 3), stoa(addr), text);
		fflush(clockstats.fp);
	}
}

/*
 * record_raw_stats - write raw timestamps to file
 *
 *
 * file format
 * time (s past midnight)
 * peer ip address
 * local ip address
 * t1 t2 t3 t4 timestamps
 */
void
record_raw_stats(
        struct sockaddr_storage *srcadr,
        struct sockaddr_storage *dstadr,
	l_fp	*t1,
	l_fp	*t2,
	l_fp	*t3,
	l_fp	*t4
	)
{
	l_fp	now;
	u_long	day;

	if (!stats_control)
		return;

	get_systime(&now);
	filegen_setup(&rawstats, now.l_ui);
	day = now.l_ui / 86400 + MJD_1900;
	now.l_ui %= 86400;
	if (rawstats.fp != NULL) {
                fprintf(rawstats.fp, "%lu %s %s %s %s %s %s %s\n",
			day, ulfptoa(&now, 3), stoa(srcadr), dstadr ? stoa(dstadr) : "-",
			ulfptoa(t1, 9), ulfptoa(t2, 9), ulfptoa(t3, 9),
			ulfptoa(t4, 9));
		fflush(rawstats.fp);
	}
}


/*
 * record_sys_stats - write system statistics to file
 *
 * file format
 * time (s past midnight)
 * time since startup (hr)
 * packets recieved
 * packets processed
 * current version
 * previous version
 * bad version
 * access denied
 * bad length or format
 * bad authentication
 * rate exceeded
 */
void
record_sys_stats(void)
{
	l_fp	now;
	u_long	day;

	if (!stats_control)
		return;

	get_systime(&now);
	filegen_setup(&sysstats, now.l_ui);
	day = now.l_ui / 86400 + MJD_1900;
	now.l_ui %= 86400;
	if (sysstats.fp != NULL) {
                fprintf(sysstats.fp,
		    "%lu %s %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu\n",
		    day, ulfptoa(&now, 3), sys_stattime / 3600,
		    sys_received, sys_processed, sys_newversionpkt,
		    sys_oldversionpkt, sys_unknownversion,
		    sys_restricted, sys_badlength, sys_badauth,
		    sys_limitrejected);
		fflush(sysstats.fp);
		proto_clr_stats();
	}
}


#ifdef OPENSSL
/*
 * record_crypto_stats - write crypto statistics to file
 *
 * file format:
 * day (mjd)
 * time (s past midnight)
 * peer (ip address)
 * text message
 */
void
record_crypto_stats(
	struct sockaddr_storage *addr,
	const char *text
	)
{
	l_fp	now;
	u_long	day;

	if (!stats_control)
		return;

	get_systime(&now);
	filegen_setup(&cryptostats, now.l_ui);
	day = now.l_ui / 86400 + MJD_1900;
	now.l_ui %= 86400;
	if (cryptostats.fp != NULL) {
		if (addr == NULL)
			fprintf(cryptostats.fp, "%lu %s %s\n",
			    day, ulfptoa(&now, 3), text);
		else
			fprintf(cryptostats.fp, "%lu %s %s %s\n",
			    day, ulfptoa(&now, 3), stoa(addr), text);
		fflush(cryptostats.fp);
	}
}
#endif /* OPENSSL */

#ifdef DEBUG_TIMING
/*
 * record_crypto_stats - write crypto statistics to file
 *
 * file format:
 * day (mjd)
 * time (s past midnight)
 * text message
 */
void
record_timing_stats(
	const char *text
	)
{
	static unsigned int flshcnt;
	l_fp	now;
	u_long	day;

	if (!stats_control)
		return;

	get_systime(&now);
	filegen_setup(&timingstats, now.l_ui);
	day = now.l_ui / 86400 + MJD_1900;
	now.l_ui %= 86400;
	if (timingstats.fp != NULL) {
		fprintf(timingstats.fp, "%lu %s %s\n",
			    day, lfptoa(&now, 3), text);
		if (++flshcnt % 100 == 0)
			fflush(timingstats.fp);
	}
}
#endif
/*
 * getauthkeys - read the authentication keys from the specified file
 */
void
getauthkeys(
	const char *keyfile
	)
{
	int len;

	len = strlen(keyfile);
	if (len == 0)
		return;
	
	if (key_file_name != 0) {
		if (len > (int)strlen(key_file_name)) {
			(void) free(key_file_name);
			key_file_name = 0;
		}
	}

	if (key_file_name == 0) {
#ifndef SYS_WINNT
		key_file_name = (char*)emalloc((u_int) (len + 1));
#else
		key_file_name = (char*)emalloc((u_int)  (MAXPATHLEN));
#endif
	}
#ifndef SYS_WINNT
 	memmove(key_file_name, keyfile, (unsigned)(len+1));
#else
	if (!ExpandEnvironmentStrings(keyfile, key_file_name, MAXPATHLEN)) 
	{
		msyslog(LOG_ERR,
		    "ExpandEnvironmentStrings(KEY_FILE) failed: %m\n");
	}
#endif /* SYS_WINNT */

	authreadkeys(key_file_name);
}


/*
 * rereadkeys - read the authentication key file over again.
 */
void
rereadkeys(void)
{
	if (key_file_name != 0)
	    authreadkeys(key_file_name);
}

/*
 * sock_hash - hash an sockaddr_storage structure
 */
int
sock_hash(
	struct sockaddr_storage *addr
	)
{
	int hashVal;
	int i;
	int len;
	char *ch;

	hashVal = 0;
	len = 0;
	/*
	 * We can't just hash the whole thing because there are hidden
	 * fields in sockaddr_in6 that might be filled in by recvfrom(),
	 * so just use the family, port and address.
	 */
	ch = (char *)&addr->ss_family;
	hashVal = 37 * hashVal + (int)*ch;
	if (sizeof(addr->ss_family) > 1) {
		ch++;
		hashVal = 37 * hashVal + (int)*ch;
	}
	switch(addr->ss_family) {
	case AF_INET:
		ch = (char *)&((struct sockaddr_in *)addr)->sin_addr;
		len = sizeof(struct in_addr);
		break;
	case AF_INET6:
		ch = (char *)&((struct sockaddr_in6 *)addr)->sin6_addr;
		len = sizeof(struct in6_addr);
		break;
	}

	for (i = 0; i < len ; i++)
		hashVal = 37 * hashVal + (int)*(ch + i);

	hashVal = hashVal % 128;  /* % MON_HASH_SIZE hardcoded */

	if (hashVal < 0)
		hashVal += 128;

	return hashVal;
}

#if notyet
/*
 * ntp_exit - document explicitly that ntpd has exited
 */
void
ntp_exit(int retval)
{
  msyslog(LOG_ERR, "EXITING with return code %d", retval);
  exit(retval);
}
#endif

#define kMaxUUIDLen 37

/* Did we wake up since last check? Use SL API */
/* for Leopard could trigger off changes to kern.waketime */
int awoke(void)
{
    static char sleepwakeuuid[kMaxUUIDLen];
    int rc = 0;
    io_service_t service = IORegistryEntryFromPath(kIOMasterPortDefault, 
						   kIOPowerPlane ":/IOPowerConnection/IOPMrootDomain");
    CFStringRef uuidString = IORegistryEntryCreateCFProperty(
	    service,
	    CFSTR(kIOPMSleepWakeUUIDKey),
	    kCFAllocatorDefault, 0);
    if (uuidString) {
	    char newuuid[kMaxUUIDLen];
	    CFStringGetCString(uuidString, newuuid, sizeof(newuuid), 
			       kCFStringEncodingUTF8);
	    rc = strncasecmp(newuuid, sleepwakeuuid, sizeof(newuuid));
	    if (rc) {
		    strlcpy(sleepwakeuuid, newuuid, sizeof(sleepwakeuuid));
	    }
	    CFRelease(uuidString);
    }
    IOObjectRelease(service);
    return rc;
}