diff options
Diffstat (limited to 'src/systemd-timesyncd/timesyncd.c')
| -rw-r--r-- | src/systemd-timesyncd/timesyncd.c | 165 |
1 files changed, 165 insertions, 0 deletions
diff --git a/src/systemd-timesyncd/timesyncd.c b/src/systemd-timesyncd/timesyncd.c new file mode 100644 index 0000000000..047f455d18 --- /dev/null +++ b/src/systemd-timesyncd/timesyncd.c @@ -0,0 +1,165 @@ +/*** + This file is part of systemd. + + Copyright 2014 Kay Sievers, Lennart Poettering + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include <systemd/sd-daemon.h> +#include <systemd/sd-event.h> + +#include "sd-network/network-util.h" +#include "systemd-basic/capability-util.h" +#include "systemd-basic/clock-util.h" +#include "systemd-basic/fd-util.h" +#include "systemd-basic/fs-util.h" +#include "systemd-basic/signal-util.h" +#include "systemd-basic/user-util.h" + +#include "timesyncd-conf.h" +#include "timesyncd-manager.h" + +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 + * have a new NTP time, or when we shut down, and restoring it + * when we start again. This is particularly helpful on + * systems lacking a battery backed RTC. We also will adjust + * the time to at least the build time of systemd. */ + + fd = open("/var/lib/systemd/clock", O_RDWR|O_CLOEXEC, 0644); + if (fd >= 0) { + struct stat st; + 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; + } + + /* Try to fix the access mode, so that we can still + touch the file after dropping priviliges */ + (void) fchmod(fd, 0644); + (void) fchown(fd, uid, gid); + + } else + /* create stamp file with the compiled-in date */ + (void) touch_file("/var/lib/systemd/clock", true, min, uid, gid, 0644); + + ct = now(CLOCK_REALTIME); + if (ct < min) { + struct timespec ts; + char date[FORMAT_TIMESTAMP_MAX]; + + log_info("System clock time unset or jumped backwards, restoring from recorded timestamp: %s", + format_timestamp(date, sizeof(date), min)); + + if (clock_settime(CLOCK_REALTIME, timespec_store(&ts, min)) < 0) + log_error_errno(errno, "Failed to restore system clock: %m"); + } + + return 0; +} + +int main(int argc, char *argv[]) { + _cleanup_(manager_freep) Manager *m = NULL; + const char *user = "systemd-timesync"; + uid_t uid; + gid_t gid; + int r; + + log_set_target(LOG_TARGET_AUTO); + log_set_facility(LOG_CRON); + log_parse_environment(); + log_open(); + + umask(0022); + + if (argc != 1) { + log_error("This program does not take arguments."); + r = -EINVAL; + goto finish; + } + + r = get_user_creds(&user, &uid, &gid, NULL, NULL); + if (r < 0) { + log_error_errno(r, "Cannot resolve user name %s: %m", user); + goto finish; + } + + r = load_clock_timestamp(uid, gid); + if (r < 0) + goto finish; + + r = drop_privileges(uid, gid, (1ULL << CAP_SYS_TIME)); + if (r < 0) + goto finish; + + assert_se(sigprocmask_many(SIG_BLOCK, NULL, SIGTERM, SIGINT, -1) >= 0); + + r = manager_new(&m); + if (r < 0) { + log_error_errno(r, "Failed to allocate manager: %m"); + goto finish; + } + + if (clock_is_localtime(NULL) > 0) { + log_info("The system is configured to read the RTC time in the local time zone. " + "This mode can not be fully supported. All system time to RTC updates are disabled."); + m->rtc_local_time = true; + } + + r = manager_parse_config_file(m); + if (r < 0) + log_warning_errno(r, "Failed to parse configuration file: %m"); + + log_debug("systemd-timesyncd running as pid " PID_FMT, getpid()); + sd_notify(false, + "READY=1\n" + "STATUS=Daemon is running"); + + if (network_is_online()) { + r = manager_connect(m); + if (r < 0) + goto finish; + } + + r = sd_event_loop(m->event); + if (r < 0) { + log_error_errno(r, "Failed to run event loop: %m"); + goto finish; + } + + /* if we got an authoritative time, store it in the file system */ + if (m->sync) + (void) touch("/var/lib/systemd/clock"); + + sd_event_get_exit_code(m->event, &r); + +finish: + sd_notify(false, + "STOPPING=1\n" + "STATUS=Shutting down..."); + + return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS; +} |