/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ /*** 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 "sd-event.h" #include "sd-daemon.h" #include "capability.h" #include "clock-util.h" #include "network-util.h" #include "timesyncd-manager.h" #include "timesyncd-conf.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 */ 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 (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; /* We need one process for ourselves, plus one thread for the asynchronous resolver */ if (setrlimit(RLIMIT_NPROC, &RLIMIT_MAKE_CONST(2)) < 0) log_warning_errno(errno, "Failed to lower RLIMIT_NPROC to 2: %m"); assert_se(sigprocmask_many(SIG_BLOCK, 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() > 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 %lu", (unsigned long) 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) 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; }