diff options
Diffstat (limited to 'src/libsystemd-basic/src/clock-util.c')
| -rw-r--r-- | src/libsystemd-basic/src/clock-util.c | 166 |
1 files changed, 166 insertions, 0 deletions
diff --git a/src/libsystemd-basic/src/clock-util.c b/src/libsystemd-basic/src/clock-util.c new file mode 100644 index 0000000000..959af6c569 --- /dev/null +++ b/src/libsystemd-basic/src/clock-util.c @@ -0,0 +1,166 @@ +/*** + 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 <stdio.h> +#include <sys/ioctl.h> +#include <sys/time.h> +#include <time.h> + +#include <linux/rtc.h> + +#include "systemd-basic/clock-util.h" +#include "systemd-basic/fd-util.h" +#include "systemd-basic/macro.h" +#include "systemd-basic/string-util.h" +#include "systemd-basic/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(const char* adjtime_path) { + _cleanup_fclose_ FILE *f; + + if (adjtime_path == NULL) + adjtime_path = "/etc/adjtime"; + + /* + * The third line of adjtime is "UTC" or "LOCAL" or nothing. + * # /etc/adjtime + * 0.0 0 0 + * 0 + * UTC + */ + f = fopen(adjtime_path, "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) + /* less than three lines -> default to UTC */ + return 0; + + truncate_nl(line); + return streq(line, "LOCAL"); + + } else if (errno != ENOENT) + return -errno; + + /* adjtime not present -> default to UTC */ + 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; +} |