Systemd/src/shared/clock-util.c
Zbigniew Jędrzejewski-Szmek d284b82b3e Move various files that don't need to be in basic/ to shared/
This doesn't have much effect on the final build, because we link libbasic.a
into libsystemd-shared.so, so in the end, all the object built from basic/
end up in libsystemd-shared. And when the static library is linked into binaries,
any objects that are included in it but are not used are trimmed. Hence, the
size of output artifacts doesn't change:

$ du -sb /var/tmp/inst*
54181861	/var/tmp/inst1    (old)
54207441	/var/tmp/inst1s   (old split-usr)
54182477	/var/tmp/inst2    (new)
54208041	/var/tmp/inst2s   (new split-usr)

(The negligible change in size is because libsystemd-shared.so is bigger
by a few hundred bytes. I guess it's because symbols are named differently
or something like that.)

The effect is on the build process, in particular partial builds. This change
effectively moves the requirements on some build steps toward the leaves of the
dependency tree. Two effects:
- when building items that do not depend on libsystemd-shared, we
  build less stuff for libbasic.a (which wouldn't be used anyway,
  so it's a net win).
- when building items that do depend on libshared, we reduce libbasic.a as a
  synchronization point, possibly allowing better parallelism.

Method:
1. copy list of .h files from src/basic/meson.build to /tmp/basic
2. $ for i in $(grep '.h$' /tmp/basic); do echo $i; git --no-pager grep "include \"$i\"" src/basic/ 'src/lib*' 'src/nss-*' 'src/journal/sd-journal.c' |grep -v "${i%.h}.c";echo ;done | less
2018-11-20 07:27:37 +01:00

158 lines
4.1 KiB
C

/* SPDX-License-Identifier: LGPL-2.1+ */
#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 "alloc-util.h"
#include "clock-util.h"
#include "fd-util.h"
#include "fileio.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(const char* adjtime_path) {
_cleanup_fclose_ FILE *f;
int r;
if (!adjtime_path)
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) {
_cleanup_free_ char *line = NULL;
unsigned i;
for (i = 0; i < 2; i++) { /* skip the first two lines */
r = read_line(f, LONG_LINE_MAX, NULL);
if (r < 0)
return r;
if (r == 0)
return false; /* less than three lines → default to UTC */
}
r = read_line(f, LONG_LINE_MAX, &line);
if (r < 0)
return r;
if (r == 0)
return false; /* less than three lines → default to UTC */
return streq(line, "LOCAL");
} else if (errno != ENOENT)
return -errno;
/* adjtime not present → default to UTC */
return false;
}
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(localtime_r(&ts.tv_sec, &tm));
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;
}