From b750101eb236130cf056c675997decbac904cc49 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 17:35:18 +0200 Subject: Adding upstream version 252.22. Signed-off-by: Daniel Baumann --- src/shared/clock-util.c | 167 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 167 insertions(+) create mode 100644 src/shared/clock-util.c (limited to 'src/shared/clock-util.c') diff --git a/src/shared/clock-util.c b/src/shared/clock-util.c new file mode 100644 index 0000000..a4c00d7 --- /dev/null +++ b/src/shared/clock-util.c @@ -0,0 +1,167 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "alloc-util.h" +#include "clock-util.h" +#include "errno-util.h" +#include "fd-util.h" +#include "fileio.h" +#include "macro.h" +#include "string-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; + + return RET_NERRNO(ioctl(fd, RTC_SET_TIME, tm)); +} + +int clock_is_localtime(const char* adjtime_path) { + _cleanup_fclose_ FILE *f = NULL; + 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 *ret_minutesdelta) { + 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 = (struct timezone) { + .tz_minuteswest = -minutesdelta, + .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(NULL, &tz) < 0) + return -errno; + + if (ret_minutesdelta) + *ret_minutesdelta = minutesdelta; + + return 0; +} + +int clock_reset_timewarp(void) { + static const struct timezone tz = { + .tz_minuteswest = 0, + .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. */ + return RET_NERRNO(settimeofday(NULL, &tz)); +} + +#define EPOCH_FILE "/usr/lib/clock-epoch" + +int clock_apply_epoch(ClockChangeDirection *ret_attempted_change) { + usec_t epoch_usec, now_usec; + struct stat st; + + /* NB: we update *ret_attempted_change in *all* cases, both + * on success and failure, to indicate what we intended to do! */ + + assert(ret_attempted_change); + + if (stat(EPOCH_FILE, &st) < 0) { + if (errno != ENOENT) + log_warning_errno(errno, "Cannot stat " EPOCH_FILE ": %m"); + + epoch_usec = (usec_t) TIME_EPOCH * USEC_PER_SEC; + } else + epoch_usec = timespec_load(&st.st_mtim); + + now_usec = now(CLOCK_REALTIME); + if (now_usec < epoch_usec) + *ret_attempted_change = CLOCK_CHANGE_FORWARD; + else if (CLOCK_VALID_RANGE_USEC_MAX > 0 && now_usec > usec_add(epoch_usec, CLOCK_VALID_RANGE_USEC_MAX)) + *ret_attempted_change = CLOCK_CHANGE_BACKWARD; + else { + *ret_attempted_change = CLOCK_CHANGE_NOOP; + return 0; + } + + if (clock_settime(CLOCK_REALTIME, TIMESPEC_STORE(epoch_usec)) < 0) + return -errno; + + return 1; +} -- cgit v1.2.3