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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* vim: set ts=8 sts=2 et sw=2 tw=80:
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
#include "vm/DateTime.h"
#if JS_HAS_INTL_API
# include "mozilla/intl/ICU4CGlue.h"
# include "mozilla/intl/TimeZone.h"
#endif
#include "mozilla/ScopeExit.h"
#include "mozilla/Span.h"
#include "mozilla/TextUtils.h"
#include <algorithm>
#include <cstdlib>
#include <cstring>
#include <iterator>
#include <string_view>
#include <time.h>
#if !defined(XP_WIN)
# include <limits.h>
# include <unistd.h>
#endif /* !defined(XP_WIN) */
#if JS_HAS_INTL_API
# include "builtin/intl/FormatBuffer.h"
#endif
#include "js/AllocPolicy.h"
#include "js/Date.h"
#include "js/GCAPI.h"
#include "js/Utility.h"
#include "js/Vector.h"
#include "threading/ExclusiveData.h"
#include "util/Text.h"
#include "vm/MutexIDs.h"
#include "vm/Realm.h"
static bool ComputeLocalTime(time_t local, struct tm* ptm) {
// Neither localtime_s nor localtime_r are required to act as if tzset has
// been called, therefore we need to explicitly call it to ensure any time
// zone changes are correctly picked up.
#if defined(_WIN32)
_tzset();
return localtime_s(ptm, &local) == 0;
#elif defined(HAVE_LOCALTIME_R)
# ifndef __wasi__
tzset();
# endif
return localtime_r(&local, ptm);
#else
struct tm* otm = localtime(&local);
if (!otm) {
return false;
}
*ptm = *otm;
return true;
#endif
}
static bool ComputeUTCTime(time_t t, struct tm* ptm) {
#if defined(_WIN32)
return gmtime_s(ptm, &t) == 0;
#elif defined(HAVE_GMTIME_R)
return gmtime_r(&t, ptm);
#else
struct tm* otm = gmtime(&t);
if (!otm) {
return false;
}
*ptm = *otm;
return true;
#endif
}
/*
* Compute the offset in seconds from the current UTC time to the current local
* standard time (i.e. not including any offset due to DST).
*
* Examples:
*
* Suppose we are in California, USA on January 1, 2013 at 04:00 PST (UTC-8, no
* DST in effect), corresponding to 12:00 UTC. This function would then return
* -8 * SecondsPerHour, or -28800.
*
* Or suppose we are in Berlin, Germany on July 1, 2013 at 17:00 CEST (UTC+2,
* DST in effect), corresponding to 15:00 UTC. This function would then return
* +1 * SecondsPerHour, or +3600.
*/
static int32_t UTCToLocalStandardOffsetSeconds() {
using js::SecondsPerDay;
using js::SecondsPerHour;
using js::SecondsPerMinute;
// Get the current time.
time_t currentMaybeWithDST = time(nullptr);
if (currentMaybeWithDST == time_t(-1)) {
return 0;
}
// Break down the current time into its (locally-valued, maybe with DST)
// components.
struct tm local;
if (!ComputeLocalTime(currentMaybeWithDST, &local)) {
return 0;
}
// Compute a |time_t| corresponding to |local| interpreted without DST.
time_t currentNoDST;
if (local.tm_isdst == 0) {
// If |local| wasn't DST, we can use the same time.
currentNoDST = currentMaybeWithDST;
} else {
// If |local| respected DST, we need a time broken down into components
// ignoring DST. Turn off DST in the broken-down time. Create a fresh
// copy of |local|, because mktime() will reset tm_isdst = 1 and will
// adjust tm_hour and tm_hour accordingly.
struct tm localNoDST = local;
localNoDST.tm_isdst = 0;
// Compute a |time_t t| corresponding to the broken-down time with DST
// off. This has boundary-condition issues (for about the duration of
// a DST offset) near the time a location moves to a different time
// zone. But 1) errors will be transient; 2) locations rarely change
// time zone; and 3) in the absence of an API that provides the time
// zone offset directly, this may be the best we can do.
currentNoDST = mktime(&localNoDST);
if (currentNoDST == time_t(-1)) {
return 0;
}
}
// Break down the time corresponding to the no-DST |local| into UTC-based
// components.
struct tm utc;
if (!ComputeUTCTime(currentNoDST, &utc)) {
return 0;
}
// Finally, compare the seconds-based components of the local non-DST
// representation and the UTC representation to determine the actual
// difference.
int utc_secs = utc.tm_hour * SecondsPerHour + utc.tm_min * SecondsPerMinute;
int local_secs =
local.tm_hour * SecondsPerHour + local.tm_min * SecondsPerMinute;
// Same-day? Just subtract the seconds counts.
if (utc.tm_mday == local.tm_mday) {
return local_secs - utc_secs;
}
// If we have more UTC seconds, move local seconds into the UTC seconds'
// frame of reference and then subtract.
if (utc_secs > local_secs) {
return (SecondsPerDay + local_secs) - utc_secs;
}
// Otherwise we have more local seconds, so move the UTC seconds into the
// local seconds' frame of reference and then subtract.
return local_secs - (utc_secs + SecondsPerDay);
}
void js::DateTimeInfo::internalResetTimeZone(ResetTimeZoneMode mode) {
#if JS_HAS_INTL_API
MOZ_ASSERT(!timeZoneOverride_, "only valid for default instance");
#endif
// Nothing to do when an update request is already enqueued.
if (timeZoneStatus_ == TimeZoneStatus::NeedsUpdate) {
return;
}
// Mark the state as needing an update, but defer the actual update until it's
// actually needed to delay any system calls to the last possible moment. This
// is beneficial when this method is called during start-up, because it avoids
// main-thread I/O blocking the process.
if (mode == ResetTimeZoneMode::ResetEvenIfOffsetUnchanged) {
timeZoneStatus_ = TimeZoneStatus::NeedsUpdate;
} else {
timeZoneStatus_ = TimeZoneStatus::UpdateIfChanged;
}
}
void js::DateTimeInfo::resetState() {
dstRange_.reset();
#if JS_HAS_INTL_API
utcRange_.reset();
localRange_.reset();
{
// Tell the analysis the |pFree| function pointer called by uprv_free
// cannot GC.
JS::AutoSuppressGCAnalysis nogc;
timeZone_ = nullptr;
}
timeZoneId_ = nullptr;
standardName_ = nullptr;
daylightSavingsName_ = nullptr;
#endif /* JS_HAS_INTL_API */
}
#if JS_HAS_INTL_API
void js::DateTimeInfo::updateTimeZoneOverride(
RefPtr<JS::TimeZoneString> timeZone) {
MOZ_RELEASE_ASSERT(timeZoneOverride_, "can't change default instance");
MOZ_ASSERT(timeZone);
// Reset state when time zone override changed.
if (std::strcmp(timeZoneOverride_->chars(), timeZone->chars()) != 0) {
timeZoneOverride_ = timeZone;
// Reuse the |utcToLocalStandardOffsetSeconds_| as the cache key.
utcToLocalStandardOffsetSeconds_++;
resetState();
}
}
#endif
void js::DateTimeInfo::updateTimeZone() {
MOZ_ASSERT(timeZoneStatus_ != TimeZoneStatus::Valid);
#if JS_HAS_INTL_API
MOZ_ASSERT(!timeZoneOverride_, "only valid for default instance");
#endif
bool updateIfChanged = timeZoneStatus_ == TimeZoneStatus::UpdateIfChanged;
timeZoneStatus_ = TimeZoneStatus::Valid;
/*
* The difference between local standard time and UTC will never change for
* a given time zone.
*/
int32_t newOffset = UTCToLocalStandardOffsetSeconds();
if (updateIfChanged && newOffset == utcToLocalStandardOffsetSeconds_) {
return;
}
utcToLocalStandardOffsetSeconds_ = newOffset;
resetState();
// Propagate the time zone change to ICU, too.
{
// Tell the analysis calling into ICU cannot GC.
JS::AutoSuppressGCAnalysis nogc;
internalResyncICUDefaultTimeZone();
}
}
js::DateTimeInfo::DateTimeInfo() {
// Set the time zone status into the invalid state, so we compute the actual
// defaults on first access. We don't yet want to initialize neither <ctime>
// nor ICU's time zone classes, because that may cause I/O operations slowing
// down the JS engine initialization, which we're currently in the middle of.
timeZoneStatus_ = TimeZoneStatus::NeedsUpdate;
}
#if JS_HAS_INTL_API
js::DateTimeInfo::DateTimeInfo(RefPtr<JS::TimeZoneString> timeZone)
: utcToLocalStandardOffsetSeconds_(SecondsPerDay),
timeZoneOverride_(timeZone) {
MOZ_ASSERT(timeZone);
// |utcToLocalStandardOffsetSeconds_| is initialized to |SecondsPerDay| to
// ensure it's larger than any valid time zone offset as computed by
// |UTCToLocalStandardOffsetSeconds()|.
// Manually reset all internal state, because |updateTimeZone| is never called
// when a time zone override is used.
resetState();
}
#endif
js::DateTimeInfo::~DateTimeInfo() = default;
int64_t js::DateTimeInfo::toClampedSeconds(int64_t milliseconds) {
int64_t seconds = milliseconds / msPerSecond;
int64_t millis = milliseconds % msPerSecond;
// Round towards the start of time.
if (millis < 0) {
seconds -= 1;
}
if (seconds > MaxTimeT) {
seconds = MaxTimeT;
} else if (seconds < MinTimeT) {
/* Go ahead a day to make localtime work (does not work with 0). */
seconds = MinTimeT + SecondsPerDay;
}
return seconds;
}
int32_t js::DateTimeInfo::computeDSTOffsetMilliseconds(int64_t utcSeconds) {
MOZ_ASSERT(utcSeconds >= MinTimeT);
MOZ_ASSERT(utcSeconds <= MaxTimeT);
#if JS_HAS_INTL_API
int64_t utcMilliseconds = utcSeconds * msPerSecond;
return timeZone()->GetDSTOffsetMs(utcMilliseconds).unwrapOr(0);
#else
struct tm tm;
if (!ComputeLocalTime(static_cast<time_t>(utcSeconds), &tm)) {
return 0;
}
// NB: The offset isn't computed correctly when the standard local offset
// at |utcSeconds| is different from |utcToLocalStandardOffsetSeconds|.
int32_t dayoff =
int32_t((utcSeconds + utcToLocalStandardOffsetSeconds_) % SecondsPerDay);
int32_t tmoff = tm.tm_sec + (tm.tm_min * SecondsPerMinute) +
(tm.tm_hour * SecondsPerHour);
int32_t diff = tmoff - dayoff;
if (diff < 0) {
diff += SecondsPerDay;
} else if (uint32_t(diff) >= SecondsPerDay) {
diff -= SecondsPerDay;
}
return diff * int32_t(msPerSecond);
#endif /* JS_HAS_INTL_API */
}
int32_t js::DateTimeInfo::internalGetDSTOffsetMilliseconds(
int64_t utcMilliseconds) {
int64_t utcSeconds = toClampedSeconds(utcMilliseconds);
return getOrComputeValue(dstRange_, utcSeconds,
&DateTimeInfo::computeDSTOffsetMilliseconds);
}
int32_t js::DateTimeInfo::getOrComputeValue(RangeCache& range, int64_t seconds,
ComputeFn compute) {
range.sanityCheck();
auto checkSanity =
mozilla::MakeScopeExit([&range]() { range.sanityCheck(); });
// NB: Be aware of the initial range values when making changes to this
// code: the first call to this method, with those initial range
// values, must result in a cache miss.
MOZ_ASSERT(seconds != INT64_MIN);
if (range.startSeconds <= seconds && seconds <= range.endSeconds) {
return range.offsetMilliseconds;
}
if (range.oldStartSeconds <= seconds && seconds <= range.oldEndSeconds) {
return range.oldOffsetMilliseconds;
}
range.oldOffsetMilliseconds = range.offsetMilliseconds;
range.oldStartSeconds = range.startSeconds;
range.oldEndSeconds = range.endSeconds;
if (range.startSeconds <= seconds) {
int64_t newEndSeconds =
std::min({range.endSeconds + RangeExpansionAmount, MaxTimeT});
if (newEndSeconds >= seconds) {
int32_t endOffsetMilliseconds = (this->*compute)(newEndSeconds);
if (endOffsetMilliseconds == range.offsetMilliseconds) {
range.endSeconds = newEndSeconds;
return range.offsetMilliseconds;
}
range.offsetMilliseconds = (this->*compute)(seconds);
if (range.offsetMilliseconds == endOffsetMilliseconds) {
range.startSeconds = seconds;
range.endSeconds = newEndSeconds;
} else {
range.endSeconds = seconds;
}
return range.offsetMilliseconds;
}
range.offsetMilliseconds = (this->*compute)(seconds);
range.startSeconds = range.endSeconds = seconds;
return range.offsetMilliseconds;
}
int64_t newStartSeconds =
std::max<int64_t>({range.startSeconds - RangeExpansionAmount, MinTimeT});
if (newStartSeconds <= seconds) {
int32_t startOffsetMilliseconds = (this->*compute)(newStartSeconds);
if (startOffsetMilliseconds == range.offsetMilliseconds) {
range.startSeconds = newStartSeconds;
return range.offsetMilliseconds;
}
range.offsetMilliseconds = (this->*compute)(seconds);
if (range.offsetMilliseconds == startOffsetMilliseconds) {
range.startSeconds = newStartSeconds;
range.endSeconds = seconds;
} else {
range.startSeconds = seconds;
}
return range.offsetMilliseconds;
}
range.startSeconds = range.endSeconds = seconds;
range.offsetMilliseconds = (this->*compute)(seconds);
return range.offsetMilliseconds;
}
void js::DateTimeInfo::RangeCache::reset() {
// The initial range values are carefully chosen to result in a cache miss
// on first use given the range of possible values. Be careful to keep
// these values and the caching algorithm in sync!
offsetMilliseconds = 0;
startSeconds = endSeconds = INT64_MIN;
oldOffsetMilliseconds = 0;
oldStartSeconds = oldEndSeconds = INT64_MIN;
sanityCheck();
}
void js::DateTimeInfo::RangeCache::sanityCheck() {
auto assertRange = [](int64_t start, int64_t end) {
MOZ_ASSERT(start <= end);
MOZ_ASSERT_IF(start == INT64_MIN, end == INT64_MIN);
MOZ_ASSERT_IF(end == INT64_MIN, start == INT64_MIN);
MOZ_ASSERT_IF(start != INT64_MIN, start >= MinTimeT && end >= MinTimeT);
MOZ_ASSERT_IF(start != INT64_MIN, start <= MaxTimeT && end <= MaxTimeT);
};
assertRange(startSeconds, endSeconds);
assertRange(oldStartSeconds, oldEndSeconds);
}
#if JS_HAS_INTL_API
int32_t js::DateTimeInfo::computeUTCOffsetMilliseconds(int64_t localSeconds) {
MOZ_ASSERT(localSeconds >= MinTimeT);
MOZ_ASSERT(localSeconds <= MaxTimeT);
int64_t localMilliseconds = localSeconds * msPerSecond;
return timeZone()->GetUTCOffsetMs(localMilliseconds).unwrapOr(0);
}
int32_t js::DateTimeInfo::computeLocalOffsetMilliseconds(int64_t utcSeconds) {
MOZ_ASSERT(utcSeconds >= MinTimeT);
MOZ_ASSERT(utcSeconds <= MaxTimeT);
UDate utcMilliseconds = UDate(utcSeconds * msPerSecond);
return timeZone()->GetOffsetMs(utcMilliseconds).unwrapOr(0);
}
int32_t js::DateTimeInfo::internalGetOffsetMilliseconds(int64_t milliseconds,
TimeZoneOffset offset) {
int64_t seconds = toClampedSeconds(milliseconds);
return offset == TimeZoneOffset::UTC
? getOrComputeValue(localRange_, seconds,
&DateTimeInfo::computeLocalOffsetMilliseconds)
: getOrComputeValue(utcRange_, seconds,
&DateTimeInfo::computeUTCOffsetMilliseconds);
}
bool js::DateTimeInfo::internalTimeZoneDisplayName(
TimeZoneDisplayNameVector& result, int64_t utcMilliseconds,
const char* locale) {
MOZ_ASSERT(locale != nullptr);
// Clear any previously cached names when the default locale changed.
if (!locale_ || std::strcmp(locale_.get(), locale) != 0) {
locale_ = DuplicateString(locale);
if (!locale_) {
return false;
}
standardName_.reset();
daylightSavingsName_.reset();
}
using DaylightSavings = mozilla::intl::TimeZone::DaylightSavings;
auto daylightSavings = internalGetDSTOffsetMilliseconds(utcMilliseconds) != 0
? DaylightSavings::Yes
: DaylightSavings::No;
JS::UniqueTwoByteChars& cachedName = (daylightSavings == DaylightSavings::Yes)
? daylightSavingsName_
: standardName_;
if (!cachedName) {
// Retrieve the display name for the given locale.
intl::FormatBuffer<char16_t, 0, js::SystemAllocPolicy> buffer;
if (timeZone()->GetDisplayName(locale, daylightSavings, buffer).isErr()) {
return false;
}
cachedName = buffer.extractStringZ();
if (!cachedName) {
return false;
}
}
return result.append(cachedName.get(), js_strlen(cachedName.get()));
}
static JS::UniqueChars DeflateString(mozilla::Span<const char16_t> chars) {
MOZ_ASSERT(mozilla::IsAscii(chars));
size_t length = chars.size();
JS::UniqueChars result(js_pod_malloc<char>(length + 1));
if (!result) {
return nullptr;
}
for (size_t i = 0; i < length; i++) {
result[i] = chars[i];
}
result[length] = '\0';
return result;
}
bool js::DateTimeInfo::internalTimeZoneId(TimeZoneIdentifierVector& result) {
if (!timeZoneId_) {
intl::FormatBuffer<char16_t,
mozilla::intl::TimeZone::TimeZoneIdentifierLength,
js::SystemAllocPolicy>
buffer;
if (timeZone()->GetId(buffer).isErr()) {
return false;
}
// ICU returns the time zone identifier as UTF-16, deflate to ASCII.
timeZoneId_ = DeflateString(buffer);
if (!timeZoneId_) {
return false;
}
}
return result.append(timeZoneId_.get(), js_strlen(timeZoneId_.get()));
}
mozilla::intl::TimeZone* js::DateTimeInfo::timeZone() {
if (!timeZone_) {
mozilla::Maybe<mozilla::Span<const char>> timeZoneOverride;
if (timeZoneOverride_) {
timeZoneOverride =
mozilla::Some(mozilla::MakeStringSpan(timeZoneOverride_->chars()));
}
auto timeZone = mozilla::intl::TimeZone::TryCreate(timeZoneOverride);
// If a time zone override was specified, but couldn't be resolved to a
// valid time zone, then we ignore the override request and instead use the
// system default time zone.
if (timeZone.isErr() && timeZoneOverride_) {
timeZone = mozilla::intl::TimeZone::TryCreate();
}
// Creating the default time zone should never fail. If it should fail
// nonetheless for some reason, just crash because we don't have a way to
// propagate any errors.
MOZ_RELEASE_ASSERT(timeZone.isOk());
timeZone_ = timeZone.unwrap();
MOZ_ASSERT(timeZone_);
}
return timeZone_.get();
}
#endif /* JS_HAS_INTL_API */
/* static */ js::ExclusiveData<js::DateTimeInfo>* js::DateTimeInfo::instance;
bool js::InitDateTimeState() {
MOZ_ASSERT(!DateTimeInfo::instance, "we should be initializing only once");
DateTimeInfo::instance =
js_new<ExclusiveData<DateTimeInfo>>(mutexid::DateTimeInfoMutex);
return DateTimeInfo::instance;
}
/* static */
void js::FinishDateTimeState() {
js_delete(DateTimeInfo::instance);
DateTimeInfo::instance = nullptr;
}
void js::ResetTimeZoneInternal(ResetTimeZoneMode mode) {
js::DateTimeInfo::resetTimeZone(mode);
}
JS_PUBLIC_API void JS::ResetTimeZone() {
js::ResetTimeZoneInternal(js::ResetTimeZoneMode::ResetEvenIfOffsetUnchanged);
}
#if JS_HAS_INTL_API
# if defined(XP_WIN)
static bool IsOlsonCompatibleWindowsTimeZoneId(std::string_view tz) {
// ICU ignores the TZ environment variable on Windows and instead directly
// invokes Win API functions to retrieve the current time zone. But since
// we're still using the POSIX-derived localtime_s() function on Windows
// and localtime_s() does return a time zone adjusted value based on the
// TZ environment variable, we need to manually adjust the default ICU
// time zone if TZ is set.
//
// Windows supports the following format for TZ: tzn[+|-]hh[:mm[:ss]][dzn]
// where "tzn" is the time zone name for standard time, the time zone
// offset is positive for time zones west of GMT, and "dzn" is the
// optional time zone name when daylight savings are observed. Daylight
// savings are always based on the U.S. daylight saving rules, that means
// for example it's not possible to use "TZ=CET-1CEST" to select the IANA
// time zone "CET".
//
// When comparing this restricted format for TZ to all IANA time zone
// names, the following time zones are in the intersection of what's
// supported by Windows and is also a valid IANA time zone identifier.
//
// Even though the time zone offset is marked as mandatory on MSDN, it
// appears it defaults to zero when omitted. This in turn means we can
// also allow the time zone identifiers "UCT", "UTC", and "GMT".
static const char* const allowedIds[] = {
// From tzdata's "northamerica" file:
"EST5EDT",
"CST6CDT",
"MST7MDT",
"PST8PDT",
// From tzdata's "backward" file:
"GMT+0",
"GMT-0",
"GMT0",
"UCT",
"UTC",
// From tzdata's "etcetera" file:
"GMT",
};
for (const auto& allowedId : allowedIds) {
if (tz == allowedId) {
return true;
}
}
return false;
}
# else
static std::string_view TZContainsAbsolutePath(std::string_view tzVar) {
// A TZ environment variable may be an absolute path. The path
// format of TZ may begin with a colon. (ICU handles relative paths.)
if (tzVar.length() > 1 && tzVar[0] == ':' && tzVar[1] == '/') {
return tzVar.substr(1);
}
if (tzVar.length() > 0 && tzVar[0] == '/') {
return tzVar;
}
return {};
}
/**
* Reject the input if it doesn't match the time zone id pattern or legacy time
* zone names.
*
*/
static bool IsTimeZoneId(std::string_view timeZone) {
size_t timeZoneLen = timeZone.length();
if (timeZoneLen == 0) {
return false;
}
for (size_t i = 0; i < timeZoneLen; i++) {
char c = timeZone[i];
// According to theory.html, '.' is allowed in time zone ids, but the
// accompanying zic.c file doesn't allow it. Assume the source file is
// correct and disallow '.' here, too.
if (mozilla::IsAsciiAlphanumeric(c) || c == '_' || c == '-' || c == '+') {
continue;
}
// Reject leading, trailing, or consecutive '/' characters.
if (c == '/' && i > 0 && i + 1 < timeZoneLen && timeZone[i + 1] != '/') {
continue;
}
return false;
}
return true;
}
/**
* Given a presumptive path |tz| to a zoneinfo time zone file
* (e.g. /etc/localtime), attempt to compute the time zone encoded by that
* path by repeatedly resolving symlinks until a path containing "/zoneinfo/"
* followed by time zone looking components is found. If a symlink is broken,
* symlink-following recurs too deeply, non time zone looking components are
* encountered, or some other error is encountered, then the |result| buffer is
* left empty.
*
* If |result| is set to a non-empty string, it's only guaranteed to have
* certain syntactic validity. It might not actually *be* a time zone name.
*
* If there's an (OOM) error, |false| is returned.
*/
static bool ReadTimeZoneLink(std::string_view tz,
js::TimeZoneIdentifierVector& result) {
MOZ_ASSERT(!tz.empty());
MOZ_ASSERT(result.empty());
// The resolved link name can have different paths depending on the OS.
// Follow ICU and only search for "/zoneinfo/"; see $ICU/common/putil.cpp.
static constexpr char ZoneInfoPath[] = "/zoneinfo/";
constexpr size_t ZoneInfoPathLength = js_strlen(ZoneInfoPath);
// Stop following symlinks after a fixed depth, because some common time
// zones are stored in files whose name doesn't match an Olson time zone
// name. For example on Ubuntu, "/usr/share/zoneinfo/America/New_York" is a
// symlink to "/usr/share/zoneinfo/posixrules" and "posixrules" is not an
// Olson time zone name.
// Four hops should be a reasonable limit for most use cases.
constexpr uint32_t FollowDepthLimit = 4;
# ifdef PATH_MAX
constexpr size_t PathMax = PATH_MAX;
# else
constexpr size_t PathMax = 4096;
# endif
static_assert(PathMax > 0, "PathMax should be larger than zero");
char linkName[PathMax];
constexpr size_t linkNameLen =
std::size(linkName) - 1; // -1 to null-terminate.
// Return if the TZ value is too large.
if (tz.length() > linkNameLen) {
return true;
}
tz.copy(linkName, tz.length());
linkName[tz.length()] = '\0';
char linkTarget[PathMax];
constexpr size_t linkTargetLen =
std::size(linkTarget) - 1; // -1 to null-terminate.
uint32_t depth = 0;
// Search until we find "/zoneinfo/" in the link name.
const char* timeZoneWithZoneInfo;
while (!(timeZoneWithZoneInfo = std::strstr(linkName, ZoneInfoPath))) {
// Return if the symlink nesting is too deep.
if (++depth > FollowDepthLimit) {
return true;
}
// Return on error or if the result was truncated.
ssize_t slen = readlink(linkName, linkTarget, linkTargetLen);
if (slen < 0 || size_t(slen) >= linkTargetLen) {
return true;
}
// Ensure linkTarget is null-terminated. (readlink may not necessarily
// null-terminate the string.)
size_t len = size_t(slen);
linkTarget[len] = '\0';
// If the target is absolute, continue with that.
if (linkTarget[0] == '/') {
std::strcpy(linkName, linkTarget);
continue;
}
// If the target is relative, it must be resolved against either the
// directory the link was in, or against the current working directory.
char* separator = std::strrchr(linkName, '/');
// If the link name is just something like "foo", resolve linkTarget
// against the current working directory.
if (!separator) {
std::strcpy(linkName, linkTarget);
continue;
}
// Remove everything after the final path separator in linkName.
separator[1] = '\0';
// Return if the concatenated path name is too large.
if (std::strlen(linkName) + len > linkNameLen) {
return true;
}
// Keep it simple and just concatenate the path names.
std::strcat(linkName, linkTarget);
}
std::string_view timeZone(timeZoneWithZoneInfo + ZoneInfoPathLength);
if (!IsTimeZoneId(timeZone)) {
return true;
}
return result.append(timeZone.data(), timeZone.length());
}
# endif /* defined(XP_WIN) */
#endif /* JS_HAS_INTL_API */
void js::DateTimeInfo::internalResyncICUDefaultTimeZone() {
#if JS_HAS_INTL_API
if (const char* tzenv = std::getenv("TZ")) {
std::string_view tz(tzenv);
mozilla::Span<const char> tzid;
# if defined(XP_WIN)
// If TZ is set and its value is valid under Windows' and IANA's time zone
// identifier rules, update the ICU default time zone to use this value.
if (IsOlsonCompatibleWindowsTimeZoneId(tz)) {
tzid = mozilla::Span(tz.data(), tz.length());
} else {
// If |tz| isn't a supported time zone identifier, use the default Windows
// time zone for ICU.
}
# else
// The TZ environment variable allows both absolute and relative paths,
// optionally beginning with a colon (':'). (Relative paths, without the
// colon, are just Olson time zone names.) We need to handle absolute paths
// ourselves, including handling that they might be symlinks.
TimeZoneIdentifierVector tzidVector;
std::string_view tzlink = TZContainsAbsolutePath(tz);
if (!tzlink.empty()) {
if (!ReadTimeZoneLink(tzlink, tzidVector)) {
// Ignore OOM.
return;
}
tzid = tzidVector;
}
# ifdef ANDROID
// ICU ignores the TZ environment variable on Android. If it doesn't contain
// an absolute path, try to parse it as a time zone name.
else if (IsTimeZoneId(tz)) {
tzid = mozilla::Span(tz.data(), tz.length());
}
# endif
# endif /* defined(XP_WIN) */
if (!tzid.empty()) {
auto result = mozilla::intl::TimeZone::SetDefaultTimeZone(tzid);
if (result.isErr()) {
// Intentionally ignore any errors, because we don't have a good way to
// report errors from this function.
return;
}
// Return if the default time zone was successfully updated.
if (result.unwrap()) {
return;
}
// If SetDefaultTimeZone() succeeded, but the default time zone wasn't
// changed, proceed to set the default time zone from the host time zone.
}
}
// Intentionally ignore any errors, because we don't have a good way to report
// errors from this function.
(void)mozilla::intl::TimeZone::SetDefaultTimeZoneFromHostTimeZone();
#endif
}