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/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include <sys/stat.h>
#include <sys/time.h>
#include "sd-messages.h"
#include "clock-util.h"
#include "clock-warp.h"
#include "errno-util.h"
int clock_reset_timewarp(void) {
static const struct timezone tz = {
.tz_minuteswest = 0,
.tz_dsttime = 0, /* DST_NONE */
};
/* The very first call to settimeofday() does time warp magic. Do a dummy call here, so the time
* warping is sealed and all later calls behave as expected. */
return RET_NERRNO(settimeofday(NULL, &tz));
}
void clock_apply_epoch(bool allow_backwards) {
usec_t epoch_usec = 0, timesyncd_usec = 0;
struct stat st;
int r;
r = RET_NERRNO(stat(TIMESYNCD_CLOCK_FILE, &st));
if (r >= 0)
epoch_usec = timespec_load(&st.st_mtim);
else if (r != -ENOENT)
log_warning_errno(r, "Could not stat %s, ignoring: %m", TIMESYNCD_CLOCK_FILE);
r = RET_NERRNO(stat(EPOCH_CLOCK_FILE, &st));
if (r >= 0)
timesyncd_usec = timespec_load(&st.st_mtim);
else if (r != -ENOENT)
log_warning_errno(r, "Could not stat %s, ignoring: %m", EPOCH_CLOCK_FILE);
epoch_usec = MAX3(epoch_usec,
timesyncd_usec,
(usec_t) TIME_EPOCH * USEC_PER_SEC);
if (epoch_usec == 0) /* Weird, but may happen if mtimes were reset to 0 during compilation. */
return log_debug("Clock epoch is 0, skipping clock adjustment.");
usec_t now_usec = now(CLOCK_REALTIME);
bool advance;
if (now_usec < epoch_usec)
advance = true;
else if (CLOCK_VALID_RANGE_USEC_MAX > 0 &&
now_usec > usec_add(epoch_usec, CLOCK_VALID_RANGE_USEC_MAX) &&
allow_backwards)
advance = false;
else
return; /* Nothing to do. */
r = RET_NERRNO(clock_settime(CLOCK_REALTIME, TIMESPEC_STORE(epoch_usec)));
if (r < 0) {
if (advance)
return (void) log_error_errno(r, "Current system time is before epoch, but cannot correct: %m");
else
return (void) log_error_errno(r, "Current system time is further ahead than %s after epoch, but cannot correct: %m",
FORMAT_TIMESPAN(CLOCK_VALID_RANGE_USEC_MAX, USEC_PER_DAY));
}
const char *from =
epoch_usec == (usec_t) TIME_EPOCH * USEC_PER_SEC ? "built-in epoch" :
epoch_usec == timesyncd_usec ? "timestamp on "TIMESYNCD_CLOCK_FILE :
"timestamp on "EPOCH_CLOCK_FILE;
if (advance)
log_struct(LOG_INFO,
"MESSAGE_ID=" SD_MESSAGE_TIME_BUMP_STR,
"REALTIME_USEC=" USEC_FMT, epoch_usec,
"DIRECTION=forwards",
LOG_MESSAGE("System time advanced to %s: %s",
from,
FORMAT_TIMESTAMP(epoch_usec)));
else
log_struct(LOG_INFO,
"MESSAGE_ID=" SD_MESSAGE_TIME_BUMP_STR,
"REALTIME_USEC=" USEC_FMT, epoch_usec,
"DIRECTION=backwards",
LOG_MESSAGE("System time was further ahead than %s after %s, clock reset to %s",
FORMAT_TIMESPAN(CLOCK_VALID_RANGE_USEC_MAX, USEC_PER_DAY),
from,
FORMAT_TIMESTAMP(epoch_usec)));
}
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