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set boot time from monotonic time (#19444)

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utmp: calculate boot timestamp from monotonic timestamp instead of realtime timestamp
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caoxia2008cxx 2021-04-29 17:05:01 +08:00 committed by GitHub
parent bf8a5f6473
commit f813b62316
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1 changed files with 11 additions and 4 deletions
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15
src/update-utmp/update-utmp.c
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@ -44,7 +44,7 @@ static void context_clear(Context *c) {
#endif
}
static usec_t get_startup_time(Context *c) {
static usec_t get_startup_monotonic_time(Context *c) {
_cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
usec_t t = 0;
int r;
@ -56,7 +56,7 @@ static usec_t get_startup_time(Context *c) {
"org.freedesktop.systemd1",
"/org/freedesktop/systemd1",
"org.freedesktop.systemd1.Manager",
"UserspaceTimestamp",
"UserspaceTimestampMonotonic",
&error,
't', &t);
if (r < 0) {
@ -115,6 +115,7 @@ static int get_current_runlevel(Context *c) {
static int on_reboot(Context *c) {
int r = 0, q;
usec_t t;
usec_t boottime;
assert(c);
@ -130,9 +131,15 @@ static int on_reboot(Context *c) {
/* If this call fails it will return 0, which
* utmp_put_reboot() will then fix to the current time */
t = get_startup_time(c);
t = get_startup_monotonic_time(c);
boottime = map_clock_usec(t, CLOCK_MONOTONIC, CLOCK_REALTIME);
/* We query the recorded monotonic time here (instead of the system clock CLOCK_REALTIME),
* even though we actually want the system clock time. That's because there's a likely
* chance that the system clock wasn't set right during early boot. By manually converting
* the monotonic clock to the system clock here we can compensate
* for incorrectly set clocks during early boot. */
q = utmp_put_reboot(t);
q = utmp_put_reboot(boottime);
if (q < 0)
r = log_error_errno(q, "Failed to write utmp record: %m");