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/*-*- 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 "hwclock.h"
#include "fileio.h"
static int rtc_open(int flags) {
int fd;
DIR *d;
/*
* Some "chaotic platforms" have multiple RTCs and we need to
* find the "system RTC", which is in some setups /dev/rtc1.
*
* First, we try to find the RTC which has hctosys=1 set. If we
* don't find any we just take the first RTC that exists at all,
* then try to open /dev/rtc0.
*/
d = opendir("/sys/class/rtc");
if (!d)
goto fallback;
for (;;) {
char *p, *v;
struct dirent *de;
union dirent_storage buf;
int r;
r = readdir_r(d, &buf.de, &de);
if (r != 0)
goto fallback;
if (!de)
goto fallback;
if (ignore_file(de->d_name))
continue;
p = strjoin("/sys/class/rtc/", de->d_name, "/hctosys", NULL);
if (!p) {
closedir(d);
return -ENOMEM;
}
r = read_one_line_file(p, &v);
free(p);
if (r < 0)
continue;
r = parse_boolean(v);
free(v);
if (r <= 0)
continue;
p = strappend("/dev/", de->d_name);
if (!p) {
closedir(d);
return -ENOMEM;
}
fd = open(p, flags);
free(p);
if (fd >= 0) {
closedir(d);
return fd;
}
}
fallback:
if (d)
closedir(d);
fd = open("/dev/rtc0", flags);
if (fd < 0)
return -errno;
return fd;
}
int hwclock_get_time(struct tm *tm) {
int fd;
int err = 0;
assert(tm);
fd = rtc_open(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)
err = -errno;
/* We don't know daylight saving, so we reset this in order not
* to confused mktime(). */
tm->tm_isdst = -1;
close_nointr_nofail(fd);
return err;
}
int hwclock_set_time(const struct tm *tm) {
int fd;
int err = 0;
assert(tm);
fd = rtc_open(O_RDONLY|O_CLOEXEC);
if (fd < 0)
return -errno;
if (ioctl(fd, RTC_SET_TIME, tm) < 0)
err = -errno;
close_nointr_nofail(fd);
return err;
}
int hwclock_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 hwclock_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 hwclock_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 time zone with next call.
*/
if (settimeofday(tv_null, &tz) < 0)
return -errno;
return 0;
}
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