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- // Copyright (c) 2012 The Chromium Authors. All rights reserved.
- // Use of this source code is governed by a BSD-style license that can be
- // found in the LICENSE file.
- #include <stdint.h>
- #include <sys/time.h>
- #include <time.h>
- #include "base/time/time.h"
- #include "build/build_config.h"
- #if BUILDFLAG(IS_ANDROID) && !defined(__LP64__)
- #include <time64.h>
- #endif
- #include <unistd.h>
- #include <limits>
- #include "base/no_destructor.h"
- #include "base/numerics/safe_math.h"
- #include "base/synchronization/lock.h"
- #include "build/build_config.h"
- #include "build/chromecast_buildflags.h"
- #if BUILDFLAG(IS_NACL)
- #include "base/os_compat_nacl.h"
- #endif
- namespace {
- // This prevents a crash on traversing the environment global and looking up
- // the 'TZ' variable in libc. See: crbug.com/390567.
- base::Lock* GetSysTimeToTimeStructLock() {
- static base::NoDestructor<base::Lock> lock;
- return lock.get();
- }
- // Define a system-specific SysTime that wraps either to a time_t or
- // a time64_t depending on the host system, and associated convertion.
- // See crbug.com/162007
- #if BUILDFLAG(IS_ANDROID) && !defined(__LP64__)
- typedef time64_t SysTime;
- SysTime SysTimeFromTimeStruct(struct tm* timestruct, bool is_local) {
- base::AutoLock locked(*GetSysTimeToTimeStructLock());
- if (is_local)
- return mktime64(timestruct);
- else
- return timegm64(timestruct);
- }
- void SysTimeToTimeStruct(SysTime t, struct tm* timestruct, bool is_local) {
- base::AutoLock locked(*GetSysTimeToTimeStructLock());
- if (is_local)
- localtime64_r(&t, timestruct);
- else
- gmtime64_r(&t, timestruct);
- }
- #elif BUILDFLAG(IS_AIX)
- // The function timegm is not available on AIX.
- time_t aix_timegm(struct tm* tm) {
- time_t ret;
- char* tz;
- tz = getenv("TZ");
- if (tz) {
- tz = strdup(tz);
- }
- setenv("TZ", "GMT0", 1);
- tzset();
- ret = mktime(tm);
- if (tz) {
- setenv("TZ", tz, 1);
- free(tz);
- } else {
- unsetenv("TZ");
- }
- tzset();
- return ret;
- }
- typedef time_t SysTime;
- SysTime SysTimeFromTimeStruct(struct tm* timestruct, bool is_local) {
- base::AutoLock locked(*GetSysTimeToTimeStructLock());
- if (is_local)
- return mktime(timestruct);
- else
- return aix_timegm(timestruct);
- }
- void SysTimeToTimeStruct(SysTime t, struct tm* timestruct, bool is_local) {
- base::AutoLock locked(*GetSysTimeToTimeStructLock());
- if (is_local)
- localtime_r(&t, timestruct);
- else
- gmtime_r(&t, timestruct);
- }
- #else // MacOS (and iOS 64-bit), Linux/ChromeOS, or any other POSIX-compliant.
- typedef time_t SysTime;
- SysTime SysTimeFromTimeStruct(struct tm* timestruct, bool is_local) {
- base::AutoLock locked(*GetSysTimeToTimeStructLock());
- return is_local ? mktime(timestruct) : timegm(timestruct);
- }
- void SysTimeToTimeStruct(SysTime t, struct tm* timestruct, bool is_local) {
- base::AutoLock locked(*GetSysTimeToTimeStructLock());
- if (is_local)
- localtime_r(&t, timestruct);
- else
- gmtime_r(&t, timestruct);
- }
- #endif // BUILDFLAG(IS_ANDROID) && !defined(__LP64__)
- } // namespace
- namespace base {
- void Time::Explode(bool is_local, Exploded* exploded) const {
- const int64_t millis_since_unix_epoch =
- ToRoundedDownMillisecondsSinceUnixEpoch();
- // For systems with a Y2038 problem, use ICU as the Explode() implementation.
- if (sizeof(SysTime) < 8) {
- // TODO(b/167763382) Find an alternate solution for Chromecast devices, since
- // adding the icui18n dep significantly increases the binary size.
- #if !BUILDFLAG(IS_CASTOS) && !BUILDFLAG(IS_CAST_ANDROID)
- ExplodeUsingIcu(millis_since_unix_epoch, is_local, exploded);
- return;
- #endif // !BUILDFLAG(IS_CASTOS) && !BUILDFLAG(IS_CAST_ANDROID)
- }
- // Split the |millis_since_unix_epoch| into separate seconds and millisecond
- // components because the platform calendar-explode operates at one-second
- // granularity.
- SysTime seconds = millis_since_unix_epoch / Time::kMillisecondsPerSecond;
- int64_t millisecond = millis_since_unix_epoch % Time::kMillisecondsPerSecond;
- if (millisecond < 0) {
- // Make the the |millisecond| component positive, within the range [0,999],
- // by transferring 1000 ms from |seconds|.
- --seconds;
- millisecond += Time::kMillisecondsPerSecond;
- }
- struct tm timestruct;
- SysTimeToTimeStruct(seconds, ×truct, is_local);
- exploded->year = timestruct.tm_year + 1900;
- exploded->month = timestruct.tm_mon + 1;
- exploded->day_of_week = timestruct.tm_wday;
- exploded->day_of_month = timestruct.tm_mday;
- exploded->hour = timestruct.tm_hour;
- exploded->minute = timestruct.tm_min;
- exploded->second = timestruct.tm_sec;
- exploded->millisecond = static_cast<int>(millisecond);
- }
- // static
- bool Time::FromExploded(bool is_local, const Exploded& exploded, Time* time) {
- CheckedNumeric<int> month = exploded.month;
- month--;
- CheckedNumeric<int> year = exploded.year;
- year -= 1900;
- if (!month.IsValid() || !year.IsValid()) {
- *time = Time(0);
- return false;
- }
- struct tm timestruct;
- timestruct.tm_sec = exploded.second;
- timestruct.tm_min = exploded.minute;
- timestruct.tm_hour = exploded.hour;
- timestruct.tm_mday = exploded.day_of_month;
- timestruct.tm_mon = month.ValueOrDie();
- timestruct.tm_year = year.ValueOrDie();
- timestruct.tm_wday = exploded.day_of_week; // mktime/timegm ignore this
- timestruct.tm_yday = 0; // mktime/timegm ignore this
- timestruct.tm_isdst = -1; // attempt to figure it out
- #if !BUILDFLAG(IS_NACL) && !BUILDFLAG(IS_SOLARIS) && !BUILDFLAG(IS_AIX)
- timestruct.tm_gmtoff = 0; // not a POSIX field, so mktime/timegm ignore
- timestruct.tm_zone = nullptr; // not a POSIX field, so mktime/timegm ignore
- #endif
- int64_t seconds;
- // Certain exploded dates do not really exist due to daylight saving times,
- // and this causes mktime() to return implementation-defined values when
- // tm_isdst is set to -1. On Android, the function will return -1, while the
- // C libraries of other platforms typically return a liberally-chosen value.
- // Handling this requires the special code below.
- // SysTimeFromTimeStruct() modifies the input structure, save current value.
- struct tm timestruct0 = timestruct;
- seconds = SysTimeFromTimeStruct(×truct, is_local);
- if (seconds == -1) {
- // Get the time values with tm_isdst == 0 and 1, then select the closest one
- // to UTC 00:00:00 that isn't -1.
- timestruct = timestruct0;
- timestruct.tm_isdst = 0;
- int64_t seconds_isdst0 = SysTimeFromTimeStruct(×truct, is_local);
- timestruct = timestruct0;
- timestruct.tm_isdst = 1;
- int64_t seconds_isdst1 = SysTimeFromTimeStruct(×truct, is_local);
- // seconds_isdst0 or seconds_isdst1 can be -1 for some timezones.
- // E.g. "CLST" (Chile Summer Time) returns -1 for 'tm_isdt == 1'.
- if (seconds_isdst0 < 0)
- seconds = seconds_isdst1;
- else if (seconds_isdst1 < 0)
- seconds = seconds_isdst0;
- else
- seconds = std::min(seconds_isdst0, seconds_isdst1);
- }
- // Handle overflow. Clamping the range to what mktime and timegm might
- // return is the best that can be done here. It's not ideal, but it's better
- // than failing here or ignoring the overflow case and treating each time
- // overflow as one second prior to the epoch.
- int64_t milliseconds = 0;
- if (seconds == -1 && (exploded.year < 1969 || exploded.year > 1970)) {
- // If exploded.year is 1969 or 1970, take -1 as correct, with the
- // time indicating 1 second prior to the epoch. (1970 is allowed to handle
- // time zone and DST offsets.) Otherwise, return the most future or past
- // time representable. Assumes the time_t epoch is 1970-01-01 00:00:00 UTC.
- //
- // The minimum and maximum representible times that mktime and timegm could
- // return are used here instead of values outside that range to allow for
- // proper round-tripping between exploded and counter-type time
- // representations in the presence of possible truncation to time_t by
- // division and use with other functions that accept time_t.
- //
- // When representing the most distant time in the future, add in an extra
- // 999ms to avoid the time being less than any other possible value that
- // this function can return.
- // On Android, SysTime is int64_t, special care must be taken to avoid
- // overflows.
- const int64_t min_seconds = (sizeof(SysTime) < sizeof(int64_t))
- ? std::numeric_limits<SysTime>::min()
- : std::numeric_limits<int32_t>::min();
- const int64_t max_seconds = (sizeof(SysTime) < sizeof(int64_t))
- ? std::numeric_limits<SysTime>::max()
- : std::numeric_limits<int32_t>::max();
- if (exploded.year < 1969) {
- milliseconds = min_seconds * kMillisecondsPerSecond;
- } else {
- milliseconds = max_seconds * kMillisecondsPerSecond;
- milliseconds += (kMillisecondsPerSecond - 1);
- }
- } else {
- CheckedNumeric<int64_t> checked_millis = seconds;
- checked_millis *= kMillisecondsPerSecond;
- checked_millis += exploded.millisecond;
- if (!checked_millis.IsValid()) {
- *time = Time(0);
- return false;
- }
- milliseconds = checked_millis.ValueOrDie();
- }
- Time converted_time;
- if (!FromMillisecondsSinceUnixEpoch(milliseconds, &converted_time)) {
- *time = base::Time(0);
- return false;
- }
- // If |exploded.day_of_month| is set to 31 on a 28-30 day month, it will
- // return the first day of the next month. Thus round-trip the time and
- // compare the initial |exploded| with |utc_to_exploded| time.
- Time::Exploded to_exploded;
- if (!is_local)
- converted_time.UTCExplode(&to_exploded);
- else
- converted_time.LocalExplode(&to_exploded);
- if (ExplodedMostlyEquals(to_exploded, exploded)) {
- *time = converted_time;
- return true;
- }
- *time = Time(0);
- return false;
- }
- } // namespace base
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