fix the year 2038 problem in getDateTime

The existing codes cast uint64_t into time_t which is int32_t in
most 32-bit systems. It results overflow if the timestamp is larger
than INT_MAX.
time_t will be 64 bits in future releases of glibc. See
https://sourceware.org/bugzilla/show_bug.cgi?id=28182.

This change workarounds the year 2038 problem via boost's ptime.
std::chrono doesn't help since it is still 32 bits.

Tested on QEMU.
Example output for certificate:
{
  "Name": "HTTPS Certificate",
  "Subject": null,
  "ValidNotAfter": "2106-01-28T20:40:31Z",
  "ValidNotBefore": "2106-02-06T18:28:16Z"
}
Previously, the format is like "1969-12-31T12:00:00+00:00". Note
that the ending "+00:00" is the time zone, not ms.

Tested the schema on QEMU. No new Redfish Service Validator errors.

Signed-off-by: Nan Zhou <nanzhoumails@gmail.com>
Signed-off-by: Ed Tanous <edtanous@google.com>
Change-Id: I8ef0bee3d724184d96253c23f3919447828d3f82

1 files changed, 2 insertions, 4 deletions

diff --git a/redfish-core/lib/metric_report.hpp b/redfish-core/lib/metric_report.hpp
index c959495408..5ecab776b7 100644
--- a/redfish-core/lib/metric_report.hpp
+++ b/redfish-core/lib/metric_report.hpp
@@ -26,8 +26,7 @@ inline nlohmann::json toMetricValues(const Readings& readings)
             {"MetricId", id},
             {"MetricProperty", metadata},
             {"MetricValue", std::to_string(sensorValue)},
-            {"Timestamp",
-             crow::utility::getDateTime(static_cast<time_t>(timestamp))},
+            {"Timestamp", crow::utility::getDateTimeUint(timestamp)},
         });
     }
 
@@ -53,8 +52,7 @@ inline bool fillReport(nlohmann::json& json, const std::string& id,
     }
 
     const auto& [timestamp, readings] = *timestampReadings;
-    json["Timestamp"] =
-        crow::utility::getDateTime(static_cast<time_t>(timestamp));
+    json["Timestamp"] = crow::utility::getDateTimeUint(timestamp);
     json["MetricValues"] = toMetricValues(readings);
     return true;
 }