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-rw-r--r--src/libbasic/clock-util.c160
1 files changed, 160 insertions, 0 deletions
diff --git a/src/libbasic/clock-util.c b/src/libbasic/clock-util.c
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+++ b/src/libbasic/clock-util.c
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+/***
+ This file is part of systemd.
+
+ Copyright 2010-2012 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 <errno.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <stdbool.h>
+#include <time.h>
+#include <linux/rtc.h>
+#include <stdio.h>
+#include <sys/ioctl.h>
+#include <sys/time.h>
+
+#include "clock-util.h"
+#include "fd-util.h"
+#include "macro.h"
+#include "string-util.h"
+#include "util.h"
+
+int clock_get_hwclock(struct tm *tm) {
+ _cleanup_close_ int fd = -1;
+
+ assert(tm);
+
+ fd = open("/dev/rtc", O_RDONLY|O_CLOEXEC);
+ if (fd < 0)
+ return -errno;
+
+ /* This leaves the timezone fields of struct tm
+ * uninitialized! */
+ if (ioctl(fd, RTC_RD_TIME, tm) < 0)
+ return -errno;
+
+ /* We don't know daylight saving, so we reset this in order not
+ * to confuse mktime(). */
+ tm->tm_isdst = -1;
+
+ return 0;
+}
+
+int clock_set_hwclock(const struct tm *tm) {
+ _cleanup_close_ int fd = -1;
+
+ assert(tm);
+
+ fd = open("/dev/rtc", O_RDONLY|O_CLOEXEC);
+ if (fd < 0)
+ return -errno;
+
+ if (ioctl(fd, RTC_SET_TIME, tm) < 0)
+ return -errno;
+
+ return 0;
+}
+
+int clock_is_localtime(void) {
+ _cleanup_fclose_ FILE *f;
+
+ /*
+ * The third line of adjtime is "UTC" or "LOCAL" or nothing.
+ * # /etc/adjtime
+ * 0.0 0 0
+ * 0
+ * UTC
+ */
+ f = fopen("/etc/adjtime", "re");
+ if (f) {
+ char line[LINE_MAX];
+ bool b;
+
+ b = fgets(line, sizeof(line), f) &&
+ fgets(line, sizeof(line), f) &&
+ fgets(line, sizeof(line), f);
+ if (!b)
+ return -EIO;
+
+ truncate_nl(line);
+ return streq(line, "LOCAL");
+
+ } else if (errno != ENOENT)
+ return -errno;
+
+ return 0;
+}
+
+int clock_set_timezone(int *min) {
+ const struct timeval *tv_null = NULL;
+ struct timespec ts;
+ struct tm *tm;
+ int minutesdelta;
+ struct timezone tz;
+
+ assert_se(clock_gettime(CLOCK_REALTIME, &ts) == 0);
+ assert_se(tm = localtime(&ts.tv_sec));
+ minutesdelta = tm->tm_gmtoff / 60;
+
+ tz.tz_minuteswest = -minutesdelta;
+ tz.tz_dsttime = 0; /* DST_NONE */
+
+ /*
+ * If the RTC does not run in UTC but in local time, the very first
+ * call to settimeofday() will set the kernel's timezone and will warp the
+ * system clock, so that it runs in UTC instead of the local time we
+ * have read from the RTC.
+ */
+ if (settimeofday(tv_null, &tz) < 0)
+ return negative_errno();
+
+ if (min)
+ *min = minutesdelta;
+ return 0;
+}
+
+int clock_reset_timewarp(void) {
+ const struct timeval *tv_null = NULL;
+ struct timezone tz;
+
+ tz.tz_minuteswest = 0;
+ tz.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.
+ */
+ if (settimeofday(tv_null, &tz) < 0)
+ return -errno;
+
+ return 0;
+}
+
+#define TIME_EPOCH_USEC ((usec_t) TIME_EPOCH * USEC_PER_SEC)
+
+int clock_apply_epoch(void) {
+ struct timespec ts;
+
+ if (now(CLOCK_REALTIME) >= TIME_EPOCH_USEC)
+ return 0;
+
+ if (clock_settime(CLOCK_REALTIME, timespec_store(&ts, TIME_EPOCH_USEC)) < 0)
+ return -errno;
+
+ return 1;
+}