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authorScott James Remnant2009-03-04 18:10:43 +0100
committerKarel Zak2009-03-10 13:27:49 +0100
commit88a3372e88c4ccd2714c3d95ef4719140436214a (patch)
tree50ef4dec2a50ab7fbd753289925bc3e2d61c2188 /hwclock
parentcal: determine the first day of week from the locale (diff)
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hwclock: add --systz option to set system clock from itself
Since the system clock time is already set from the hardware clock by the kernel (when compiled with CONFIG_RTC_HCTOSYS), there's no particular need to read the hardware clock again. This option sets the system clock using itself as a reference if the hardware clock was in local time. The resulting system clock time is in UTC, with the kernel timezone set to the difference. [kzak@redhat.com: - fix the condition that controls read_adjtime() call] Signed-off-by: Scott James Remnant <scott@ubuntu.com> Signed-off-by: Karel Zak <kzak@redhat.com>
Diffstat (limited to 'hwclock')
-rw-r--r--hwclock/hwclock.819
-rw-r--r--hwclock/hwclock.c109
2 files changed, 120 insertions, 8 deletions
diff --git a/hwclock/hwclock.8 b/hwclock/hwclock.8
index 31eda21f3..7f0c53d94 100644
--- a/hwclock/hwclock.8
+++ b/hwclock/hwclock.8
@@ -54,6 +54,25 @@ This is a good option to use in one of the system startup scripts.
.B \-w, \-\-systohc
Set the Hardware Clock to the current System Time.
.TP
+.B \-\-systz
+Reset the System Time based on the current timezone.
+
+Also set the kernel's timezone value to the local timezone
+as indicated by the TZ environment variable and/or
+.IR /usr/share/zoneinfo ,
+as
+.BR tzset (3)
+would interpret them.
+The obsolete tz_dsttime field of the kernel's timezone value is set
+to DST_NONE. (For details on what this field used to mean, see
+.BR settimeofday (2).)
+
+This is an alternate option to
+.B \-\-hctosys
+that does not read the hardware clock, and may be used in system startup
+scripts for recent 2.6 kernels where you know the System Time contains
+the Hardware Clock time.
+.TP
.B \-\-adjust
Add or subtract time from the Hardware Clock to account for systematic
drift since the last time the clock was set or adjusted. See discussion
diff --git a/hwclock/hwclock.c b/hwclock/hwclock.c
index 2749c0fc7..11c606ddf 100644
--- a/hwclock/hwclock.c
+++ b/hwclock/hwclock.c
@@ -753,6 +753,82 @@ set_system_clock(const bool hclock_valid, const time_t newtime,
}
+static int
+set_system_clock_timezone(const bool testing) {
+/*----------------------------------------------------------------------------
+ Reset the System Clock from local time to UTC, based on its current
+ value and the timezone.
+
+ Also set the kernel time zone value to the value indicated by the
+ TZ environment variable and/or /usr/lib/zoneinfo/, interpreted as
+ tzset() would interpret them.
+
+ If 'testing' is true, don't actually update anything -- just say we
+ would have.
+-----------------------------------------------------------------------------*/
+ int retcode;
+ struct timeval tv;
+ struct tm *broken;
+ int minuteswest;
+ int rc;
+
+ gettimeofday(&tv, NULL);
+ if (debug) {
+ struct tm broken_time;
+ char ctime_now[200];
+
+ broken_time = *gmtime(&tv.tv_sec);
+ strftime(ctime_now, sizeof(ctime_now), "%Y/%m/%d %H:%M:%S", &broken_time);
+ printf(_("Current system time: %ld = %s\n"), (long) tv.tv_sec, ctime_now);
+ }
+
+ broken = localtime(&tv.tv_sec);
+#ifdef HAVE_TM_GMTOFF
+ minuteswest = -broken->tm_gmtoff/60; /* GNU extension */
+#else
+ minuteswest = timezone/60;
+ if (broken->tm_isdst)
+ minuteswest -= 60;
+#endif
+
+ gettimeofday(&tv, NULL);
+ tv.tv_sec += minuteswest * 60;
+
+ if (debug) {
+ struct tm broken_time;
+ char ctime_now[200];
+
+ broken_time = *gmtime(&tv.tv_sec);
+ strftime(ctime_now, sizeof(ctime_now), "%Y/%m/%d %H:%M:%S", &broken_time);
+
+ printf(_("Calling settimeofday:\n"));
+ printf(_("\tUTC: %s\n"), ctime_now);
+ printf(_("\ttv.tv_sec = %ld, tv.tv_usec = %ld\n"),
+ (long) tv.tv_sec, (long) tv.tv_usec);
+ printf(_("\ttz.tz_minuteswest = %d\n"), minuteswest);
+ }
+ if (testing) {
+ printf(_("Not setting system clock because running in test mode.\n"));
+ retcode = 0;
+ } else {
+ const struct timezone tz = { minuteswest, 0 };
+
+ rc = settimeofday(&tv, &tz);
+ if (rc) {
+ if (errno == EPERM) {
+ fprintf(stderr,
+ _("Must be superuser to set system clock.\n"));
+ retcode = EX_NOPERM;
+ } else {
+ outsyserr(_("settimeofday() failed"));
+ retcode = 1;
+ }
+ } else retcode = 0;
+ }
+ return retcode;
+}
+
+
static void
adjust_drift_factor(struct adjtime *adjtime_p,
const time_t nowtime,
@@ -1045,7 +1121,7 @@ determine_clock_access_method(const bool user_requests_ISA) {
static int
manipulate_clock(const bool show, const bool adjust, const bool noadjfile,
const bool set, const time_t set_time,
- const bool hctosys, const bool systohc,
+ const bool hctosys, const bool systohc, const bool systz,
const struct timeval startup_time,
const bool utc, const bool local_opt,
const bool testing) {
@@ -1099,7 +1175,7 @@ manipulate_clock(const bool show, const bool adjust, const bool noadjfile,
Defined only if hclock_valid is true.
*/
- if (show || adjust || hctosys || !noadjfile) {
+ if (show || adjust || hctosys || (!noadjfile && !systz)) {
/* data from HW-clock are required */
rc = synchronize_to_clock_tick();
if (rc && rc != 2) /* 2= synchronization timeout */
@@ -1143,6 +1219,16 @@ manipulate_clock(const bool show, const bool adjust, const bool noadjfile,
printf(_("Unable to set system clock.\n"));
return rc;
}
+ } else if (systz) {
+ if (!universal) {
+ rc = set_system_clock_timezone(testing);
+ if (rc) {
+ printf(_("Unable to set system clock.\n"));
+ return rc;
+ }
+ } else if (debug) {
+ printf(_("Clock in UTC, not changed.\n"));
+ }
}
if (!noadjfile)
save_adjtime(adjtime, testing);
@@ -1232,6 +1318,7 @@ usage( const char *fmt, ... ) {
" --set set the rtc to the time given with --date\n"
" -s | --hctosys set the system time from the hardware clock\n"
" -w | --systohc set the hardware clock to the current system time\n"
+ " --systz set the system time based on the current timezone\n"
" --adjust adjust the rtc to account for systematic drift since\n"
" the clock was last set or adjusted\n"
" --getepoch print out the kernel's hardware clock epoch value\n"
@@ -1305,6 +1392,7 @@ static const struct option longopts[] = {
{ "epoch", 1, 0, 137 },
{ "rtc", 1, 0, 'f' },
{ "adjfile", 1, 0, 138 },
+ { "systz", 0, 0, 139 },
{ NULL, 0, 0, 0 }
};
@@ -1330,7 +1418,7 @@ main(int argc, char **argv) {
/* Variables set by various options; show may also be set later */
/* The options debug, badyear and epoch_option are global */
- bool show, set, systohc, hctosys, adjust, getepoch, setepoch;
+ bool show, set, systohc, hctosys, systz, adjust, getepoch, setepoch;
bool utc, testing, local_opt, noadjfile, directisa;
bool ARCconsole, Jensen, SRM, funky_toy;
char *date_opt;
@@ -1360,7 +1448,7 @@ main(int argc, char **argv) {
textdomain(PACKAGE);
/* Set option defaults */
- show = set = systohc = hctosys = adjust = noadjfile = FALSE;
+ show = set = systohc = hctosys = systz = adjust = noadjfile = FALSE;
getepoch = setepoch = utc = local_opt = testing = debug = FALSE;
ARCconsole = Jensen = SRM = funky_toy = directisa = badyear = FALSE;
date_opt = NULL;
@@ -1433,6 +1521,9 @@ main(int argc, char **argv) {
case 138:
adj_file_name = optarg; /* --adjfile */
break;
+ case 139:
+ systz = TRUE; /* --systz */
+ break;
case 'f':
rtc_dev_name = optarg; /* --rtc */
break;
@@ -1464,7 +1555,8 @@ main(int argc, char **argv) {
MYNAME, argc);
}
- if (show + set + systohc + hctosys + adjust + getepoch + setepoch > 1){
+ if (show + set + systohc + hctosys + systz + adjust + getepoch
+ + setepoch > 1){
fprintf(stderr, _("You have specified multiple functions.\n"
"You can only perform one function "
"at a time.\n"));
@@ -1515,7 +1607,8 @@ main(int argc, char **argv) {
}
}
- if (!(show | set | systohc | hctosys | adjust | getepoch | setepoch))
+ if (!(show | set | systohc | hctosys | systz | adjust | getepoch
+ | setepoch))
show = 1; /* default to show */
@@ -1528,7 +1621,7 @@ main(int argc, char **argv) {
_("Sorry, only the superuser can change "
"the Hardware Clock.\n"));
permitted = FALSE;
- } else if (hctosys) {
+ } else if (systz || hctosys) {
fprintf(stderr,
_("Sorry, only the superuser can change "
"the System Clock.\n"));
@@ -1565,7 +1658,7 @@ main(int argc, char **argv) {
}
rc = manipulate_clock(show, adjust, noadjfile, set, set_time,
- hctosys, systohc, startup_time, utc,
+ hctosys, systohc, systz, startup_time, utc,
local_opt, testing);
hwclock_exit(rc);
return rc; /* Not reached */