Revert "time: add runtime sanity check"

This reverts commit 3c2e16b.

Author: MarcoFalke

src/kernel/checks.cpp

@@ -6,7 +6,6 @@
 
 #include <key.h>
 #include <random.h>
-#include <util/time.h>
 #include <util/translation.h>
 
 #include <memory>
@@ -23,10 +22,6 @@ util::Result<void> SanityChecks(const Context&)
         return util::Error{Untranslated("OS cryptographic RNG sanity check failure. Aborting.")};
     }
 
-    if (!ChronoSanityCheck()) {
-        return util::Error{Untranslated("Clock epoch mismatch. Aborting.")};
-    }
-
     return {};
 }
 

src/test/sanity_tests.cpp

@@ -4,7 +4,6 @@
 
 #include <key.h>
 #include <test/util/setup_common.h>
-#include <util/time.h>
 
 #include <boost/test/unit_test.hpp>
 
@@ -13,7 +12,6 @@ BOOST_FIXTURE_TEST_SUITE(sanity_tests, BasicTestingSetup)
 BOOST_AUTO_TEST_CASE(basic_sanity)
 {
   BOOST_CHECK_MESSAGE(ECC_InitSanityCheck() == true, "secp256k1 sanity test");
-  BOOST_CHECK_MESSAGE(ChronoSanityCheck() == true, "chrono epoch test");
 }
 
 BOOST_AUTO_TEST_SUITE_END()

src/util/time.cpp

@@ -24,49 +24,6 @@ void UninterruptibleSleep(const std::chrono::microseconds& n) { std::this_thread
 
 static std::atomic<int64_t> nMockTime(0); //!< For testing
 
-bool ChronoSanityCheck()
-{
-    // std::chrono::system_clock.time_since_epoch and time_t(0) are not guaranteed
-    // to use the Unix epoch timestamp, prior to C++20, but in practice they almost
-    // certainly will. Any differing behavior will be assumed to be an error, unless
-    // certain platforms prove to consistently deviate, at which point we'll cope
-    // with it by adding offsets.
-
-    // Create a new clock from time_t(0) and make sure that it represents 0
-    // seconds from the system_clock's time_since_epoch. Then convert that back
-    // to a time_t and verify that it's the same as before.
-    const time_t time_t_epoch{};
-    auto clock = std::chrono::system_clock::from_time_t(time_t_epoch);
-    if (std::chrono::duration_cast<std::chrono::seconds>(clock.time_since_epoch()).count() != 0) {
-        return false;
-    }
-
-    time_t time_val = std::chrono::system_clock::to_time_t(clock);
-    if (time_val != time_t_epoch) {
-        return false;
-    }
-
-    // Check that the above zero time is actually equal to the known unix timestamp.
-    struct tm epoch;
-#ifdef HAVE_GMTIME_R
-    if (gmtime_r(&time_val, &epoch) == nullptr) {
-#else
-    if (gmtime_s(&epoch, &time_val) != 0) {
-#endif
-        return false;
-    }
-
-    if ((epoch.tm_sec != 0)  ||
-       (epoch.tm_min  != 0)  ||
-       (epoch.tm_hour != 0)  ||
-       (epoch.tm_mday != 1)  ||
-       (epoch.tm_mon  != 0)  ||
-       (epoch.tm_year != 70)) {
-        return false;
-    }
-    return true;
-}
-
 NodeClock::time_point NodeClock::now() noexcept
 {
     const std::chrono::seconds mocktime{nMockTime.load(std::memory_order_relaxed)};

src/util/time.h

@@ -116,7 +116,4 @@ struct timeval MillisToTimeval(int64_t nTimeout);
  */
 struct timeval MillisToTimeval(std::chrono::milliseconds ms);
 
-/** Sanity check epoch match normal Unix epoch */
-bool ChronoSanityCheck();
-
 #endif // BITCOIN_UTIL_TIME_H