diff options
Diffstat (limited to 'src/shared/clock-util.c')
| -rw-r--r-- | src/shared/clock-util.c | 154 |
1 files changed, 154 insertions, 0 deletions
diff --git a/src/shared/clock-util.c b/src/shared/clock-util.c new file mode 100644 index 0000000000..15535732f7 --- /dev/null +++ b/src/shared/clock-util.c @@ -0,0 +1,154 @@ +/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ + +/*** + 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 <assert.h> +#include <string.h> +#include <unistd.h> +#include <errno.h> +#include <stdlib.h> +#include <signal.h> +#include <stdio.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <fcntl.h> +#include <sys/ioctl.h> +#include <stdarg.h> +#include <ctype.h> +#include <sys/prctl.h> +#include <sys/time.h> +#include <linux/rtc.h> + +#include "macro.h" +#include "util.h" +#include "log.h" +#include "strv.h" +#include "clock-util.h" +#include "fileio.h" + +int clock_get_time(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_time(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 hardware clock does not run in UTC, but in local time: + * The very first time we set the kernel's timezone, it will warp + * the clock so that it runs in UTC instead of local time. + */ + if (settimeofday(tv_null, &tz) < 0) + return -errno; + if (min) + *min = minutesdelta; + return 0; +} + +int clock_reset_timezone(void) { + const struct timeval *tv_null = NULL; + struct timezone tz; + + tz.tz_minuteswest = 0; + tz.tz_dsttime = 0; /* DST_NONE*/ + + /* + * 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. + */ + if (settimeofday(tv_null, &tz) < 0) + return -errno; + + return 0; +} |