From d636d376796ec61c1c14fa619c80d4ac62e08a19 Mon Sep 17 00:00:00 2001 From: Kay Sievers Date: Thu, 22 May 2014 21:31:46 +0900 Subject: [PATCH] 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. --- src/shared/clock-util.c | 2 +- src/timesync/timesyncd.c | 124 ++++++++++++----------------- src/timesync/timesyncd.h | 1 + units/systemd-timesyncd.service.in | 2 +- 4 files changed, 56 insertions(+), 73 deletions(-) diff --git a/src/shared/clock-util.c b/src/shared/clock-util.c index 15535732f..4f31c10b8 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 13cdef770..b28beadd3 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 471d4b0a1..4afe4b9f5 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 af91d6367..cbde3ff67 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 -- 2.30.2