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timesyncd: when updating timestamp file, use best time we know, instead of system clock

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We adjust the system clock slowly after all, even if we know a more
accurate time. Use the accurate time for the timestamp.
This commit is contained in:
Lennart Poettering 2022-03-18 16:50:59 +01:00
parent 87057128e6
commit 1f129b7fb7
1 changed files with 17 additions and 5 deletions
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22
src/timesync/timesyncd-manager.c
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@ -29,6 +29,7 @@
#include "time-util.h"
#include "timesyncd-conf.h"
#include "timesyncd-manager.h"
#include "user-util.h"
#include "util.h"
#ifndef ADJ_SETOFFSET
@ -60,7 +61,7 @@ static int manager_arm_timer(Manager *m, usec_t next);
static int manager_clock_watch_setup(Manager *m);
static int manager_listen_setup(Manager *m);
static void manager_listen_stop(Manager *m);
static int manager_save_time_and_rearm(Manager *m);
static int manager_save_time_and_rearm(Manager *m, usec_t t);
static double ntp_ts_short_to_d(const struct ntp_ts_short *ts) {
return be16toh(ts->sec) + (be16toh(ts->frac) / 65536.0);
@ -411,6 +412,7 @@ static int manager_receive_response(sd_event_source *source, int fd, uint32_t re
.msg_namelen = sizeof(server_addr),
};
struct timespec *recv_time = NULL;
triple_timestamp dts;
ssize_t len;
double origin, receive, trans, dest, delay, offset, root_distance;
bool spike;
@ -564,12 +566,18 @@ static int manager_receive_response(sd_event_source *source, int fd, uint32_t re
m->samples_jitter, spike ? " spike" : "",
m->poll_interval_usec / USEC_PER_SEC);
/* Get current monotonic/realtime clocks immediately before adjusting the latter */
triple_timestamp_get(&dts);
if (!spike) {
/* Fix up our idea of the time. */
dts.realtime = (usec_t) (dts.realtime + offset * USEC_PER_SEC);
r = manager_adjust_clock(m, offset, leap_sec);
if (r < 0)
log_error_errno(r, "Failed to call clock_adjtime(): %m");
(void) manager_save_time_and_rearm(m);
(void) manager_save_time_and_rearm(m, dts.realtime);
/* If touch fails, there isn't much we can do. Maybe it'll work next time. */
(void) touch("/run/systemd/timesync/synchronized");
@ -1124,7 +1132,7 @@ static int manager_save_time_handler(sd_event_source *s, uint64_t usec, void *us
assert(m);
(void) manager_save_time_and_rearm(m);
(void) manager_save_time_and_rearm(m, USEC_INFINITY);
return 0;
}
@ -1152,12 +1160,16 @@ int manager_setup_save_time_event(Manager *m) {
return 0;
}
static int manager_save_time_and_rearm(Manager *m) {
static int manager_save_time_and_rearm(Manager *m, usec_t t) {
int r;
assert(m);
r = touch(CLOCK_FILE);
/* Updates the timestamp file to the specified time. If 't' is USEC_INFINITY uses the current system
* clock, but otherwise uses the specified timestamp. Note that whenever we acquire an NTP sync the
* specified timestamp value might be more accurate than the system clock, since the latter is
* subject to slow adjustments. */
r = touch_file(CLOCK_FILE, false, t, UID_INVALID, GID_INVALID, MODE_INVALID);
if (r < 0)
log_debug_errno(r, "Failed to update " CLOCK_FILE ", ignoring: %m");