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authorKay Sievers <kay@vrfy.org>2014-05-22 21:31:46 +0900
committerKay Sievers <kay@vrfy.org>2014-05-24 08:04:56 +0800
commitd636d376796ec61c1c14fa619c80d4ac62e08a19 (patch)
treedd32fcbe307c6defcf36e18890ce20810e951607
parentc38dfac9ed6c1c3beb3dd88ebf82a13d1e561ff8 (diff)
timesyncd: only update stamp file when we are synchronized
Create initial stamp file with compiled-in time to prevent bootups with clocks in the future from storing invalid timestamps. At shutdown, only update the timestamp if we got an authoritative time to store.
-rw-r--r--src/shared/clock-util.c2
-rw-r--r--src/timesync/timesyncd.c124
-rw-r--r--src/timesync/timesyncd.h1
-rw-r--r--units/systemd-timesyncd.service.in2
4 files changed, 56 insertions, 73 deletions
diff --git a/src/shared/clock-util.c b/src/shared/clock-util.c
index 15535732f7..4f31c10b81 100644
--- a/src/shared/clock-util.c
+++ b/src/shared/clock-util.c
@@ -145,7 +145,7 @@ int clock_reset_timezone(void) {
/*
* The very first time we set the kernel's timezone, it will warp
* the clock. Do a dummy call here, so the time warping is sealed
- * and we set only the timezone with next call.
+ * and we set only the timezone with the next call.
*/
if (settimeofday(tv_null, &tz) < 0)
return -errno;
diff --git a/src/timesync/timesyncd.c b/src/timesync/timesyncd.c
index 13cdef7708..b28beadd31 100644
--- a/src/timesync/timesyncd.c
+++ b/src/timesync/timesyncd.c
@@ -52,6 +52,7 @@
#include "sd-network.h"
#include "event-util.h"
#include "network-util.h"
+#include "clock-util.h"
#include "capability.h"
#include "mkdir.h"
#include "timesyncd.h"
@@ -135,9 +136,27 @@ static int manager_clock_watch_setup(Manager *m);
static int manager_connect(Manager *m);
static void manager_disconnect(Manager *m);
-static int load_clock(uid_t uid, gid_t gid) {
- usec_t nt = TIME_EPOCH * USEC_PER_SEC, ct;
+static double ntp_ts_to_d(const struct ntp_ts *ts) {
+ return be32toh(ts->sec) + ((double)be32toh(ts->frac) / UINT_MAX);
+}
+
+static double ts_to_d(const struct timespec *ts) {
+ return ts->tv_sec + (1.0e-9 * ts->tv_nsec);
+}
+
+static double tv_to_d(const struct timeval *tv) {
+ return tv->tv_sec + (1.0e-6 * tv->tv_usec);
+}
+
+static double square(double d) {
+ return d * d;
+}
+
+static int load_clock_timestamp(uid_t uid, gid_t gid) {
_cleanup_close_ int fd = -1;
+ usec_t min = TIME_EPOCH * USEC_PER_SEC;
+ usec_t ct;
+ int r;
/* Let's try to make sure that the clock is always
* monotonically increasing, by saving the clock whenever we
@@ -146,83 +165,43 @@ static int load_clock(uid_t uid, gid_t gid) {
* systems lacking a battery backed RTC. We also will adjust
* the time to at least the build time of systemd. */
- mkdir_p("/var/lib/systemd", 0755);
-
- /* First, we try to create the clock file if it doesn't exist yet */
- fd = open("/var/lib/systemd/clock", O_RDWR|O_CLOEXEC|O_EXCL, 0644);
- if (fd < 0) {
-
- fd = open("/var/lib/systemd/clock", O_RDWR|O_CLOEXEC|O_CREAT, 0644);
- if (fd < 0) {
- log_error("Failed to create /var/lib/systemd/clock: %m");
- return -errno;
- }
-
- } else {
+ fd = open("/var/lib/systemd/clock", O_RDWR|O_CLOEXEC, 0644);
+ if (fd >= 0) {
struct stat st;
- usec_t ft;
-
- if (fstat(fd, &st) < 0) {
- log_error("fstat() failed: %m");
- return -errno;
+ usec_t stamp;
+
+ /* check if the recorded time is later than the compiled-in one */
+ r = fstat(fd, &st);
+ if (r >= 0) {
+ stamp = timespec_load(&st.st_mtim);
+ if (stamp > min)
+ min = stamp;
}
- ft = timespec_load(&st.st_mtim);
- if (ft > nt)
- nt = ft;
- }
+ /* Try to fix the access mode, so that we can still
+ touch the file after dropping priviliges */
+ fchmod(fd, 0644);
+ fchown(fd, uid, gid);
+
+ } else
+ /* create stamp file with the compiled-in date */
+ touch_file("/var/lib/systemd/clock", true, min, uid, gid, 0644);
ct = now(CLOCK_REALTIME);
- if (nt > ct) {
+ if (ct < min) {
struct timespec ts;
- log_info("System clock time unset or jumped backwards, restoring.");
-
- if (clock_settime(CLOCK_REALTIME, timespec_store(&ts, nt)) < 0)
- log_error("Failed to restore system clock: %m");
- }
-
- /* Try to fix the access mode, so that we can still
- touch the file after dropping priviliges */
- fchmod(fd, 0644);
- fchown(fd, uid, gid);
+ char date[FORMAT_TIMESTAMP_MAX];
- return 0;
-}
-
-static int save_clock(void) {
-
- static const struct timespec ts[2] = {
- { .tv_sec = 0, .tv_nsec = UTIME_NOW },
- { .tv_sec = 0, .tv_nsec = UTIME_NOW },
- };
-
- int r;
+ log_info("System clock time unset or jumped backwards, restoring from recorded timestamp: %s",
+ format_timestamp(date, sizeof(date), min));
- r = utimensat(-1, "/var/lib/systemd/clock", ts, AT_SYMLINK_NOFOLLOW);
- if (r < 0) {
- log_warning("Failed to touch /var/lib/systemd/clock: %m");
- return -errno;
+ if (clock_settime(CLOCK_REALTIME, timespec_store(&ts, min)) < 0)
+ log_error("Failed to restore system clock: %m");
}
return 0;
}
-static double ntp_ts_to_d(const struct ntp_ts *ts) {
- return be32toh(ts->sec) + ((double)be32toh(ts->frac) / UINT_MAX);
-}
-
-static double ts_to_d(const struct timespec *ts) {
- return ts->tv_sec + (1.0e-9 * ts->tv_nsec);
-}
-
-static double tv_to_d(const struct timeval *tv) {
- return tv->tv_sec + (1.0e-6 * tv->tv_usec);
-}
-
-static double square(double d) {
- return d * d;
-}
-
static int manager_timeout(sd_event_source *source, usec_t usec, void *userdata) {
_cleanup_free_ char *pretty = NULL;
Manager *m = userdata;
@@ -446,12 +425,11 @@ static int manager_adjust_clock(Manager *m, double offset, int leap_sec) {
}
r = clock_adjtime(CLOCK_REALTIME, &tmx);
-
- save_clock();
-
if (r < 0)
return r;
+ touch("/var/lib/systemd/clock");
+
m->drift_ppm = tmx.freq / 65536;
log_debug(" status : %04i %s\n"
@@ -744,6 +722,7 @@ static int manager_receive_response(sd_event_source *source, int fd, uint32_t re
m->poll_interval_usec / USEC_PER_SEC);
if (!spike) {
+ m->sync = true;
r = manager_adjust_clock(m, offset, leap_sec);
if (r < 0)
log_error("Failed to call clock_adjtime(): %m");
@@ -1308,7 +1287,7 @@ int main(int argc, char *argv[]) {
return r;
}
- r = load_clock(uid, gid);
+ r = load_clock_timestamp(uid, gid);
if (r < 0)
goto out;
@@ -1349,7 +1328,10 @@ int main(int argc, char *argv[]) {
}
sd_event_get_exit_code(m->event, &r);
- save_clock();
+
+ /* if we got an authoritative time, store it in the file system */
+ if (m->sync)
+ touch("/var/lib/systemd/clock");
out:
sd_notify(false, "STATUS=Shutting down...");
diff --git a/src/timesync/timesyncd.h b/src/timesync/timesyncd.h
index 471d4b0a12..4afe4b9f5b 100644
--- a/src/timesync/timesyncd.h
+++ b/src/timesync/timesyncd.h
@@ -84,6 +84,7 @@ struct Manager {
/* last change */
bool jumped;
+ bool sync;
int drift_ppm;
/* watch for time changes */
diff --git a/units/systemd-timesyncd.service.in b/units/systemd-timesyncd.service.in
index af91d63670..cbde3ff67a 100644
--- a/units/systemd-timesyncd.service.in
+++ b/units/systemd-timesyncd.service.in
@@ -20,7 +20,7 @@ Type=notify
Restart=always
RestartSec=0
ExecStart=@rootlibexecdir@/systemd-timesyncd
-CapabilityBoundingSet=CAP_SYS_TIME CAP_SETUID CAP_SETGID CAP_SETPCAP CAP_CHOWN CAP_DAC_OVERRIDE
+CapabilityBoundingSet=CAP_SYS_TIME CAP_SETUID CAP_SETGID CAP_SETPCAP CAP_CHOWN CAP_DAC_OVERRIDE CAP_FOWNER
PrivateTmp=yes
PrivateDevices=yes
WatchdogSec=1min