Implement ManagerDiagnosticData/ServiceRootUptimeSeconds

This property was added in Redfish 2022.2 to denote how long this
service has been up and available.

This implementation opts to go to systemd to get the bmcweb service
uptime rather than track it through internal process state, given that
systemd already has an API that tracks the bmcweb uptime, and bmcweb
attempts to keep as little state as possible.  Given that we already
have helper functions that give durations in milliseconds precision,
this patchset opts to keep the millisecond granularity, rather than
dropping to microsecond precision of the systemd API.  There are no use
cases that would require microsecond precision, so this patchset opts
for lower complexity.

Tested:
Redfish service validator passes.

GET /redfish/v1/Managers/bmc/ManagerDiagnosticData
Returns a ServiceRootUptime property.  Value matches systemctl status
bmcweb.
systemctl restart bmcweb, causes counter to reset.

Signed-off-by: Ed Tanous <edtanous@google.com>
Change-Id: Ie1b82c5150f3374faf0ce376402eba410e59891d

1 files changed, 50 insertions, 1 deletions

diff --git a/redfish-core/lib/manager_diagnostic_data.hpp b/redfish-core/lib/manager_diagnostic_data.hpp
index 66fc661131..14b75feaf1 100644
--- a/redfish-core/lib/manager_diagnostic_data.hpp
+++ b/redfish-core/lib/manager_diagnostic_data.hpp
@@ -9,12 +9,59 @@
 #include "routing.hpp"
 
 #include <nlohmann/json.hpp>
+#include <sdbusplus/asio/property.hpp>
 
 #include <string>
 
 namespace redfish
 {
 
+inline void
+    afterGetManagerStartTime(const std::shared_ptr<bmcweb::AsyncResp>& aResp,
+                             const boost::system::error_code& ec,
+                             uint64_t bmcwebResetTime)
+{
+    if (ec)
+    {
+        // Not all servers will be running in systemd, so ignore the error.
+        return;
+    }
+    using std::chrono::steady_clock;
+
+    std::chrono::duration<steady_clock::rep, std::micro> usReset{
+        bmcwebResetTime};
+    steady_clock::time_point resetTime{usReset};
+
+    steady_clock::time_point now = steady_clock::now();
+
+    steady_clock::duration runTime = now - resetTime;
+
+    if (runTime < steady_clock::duration::zero())
+    {
+        BMCWEB_LOG_CRITICAL << "Uptime was negative????";
+        messages::internalError(aResp->res);
+        return;
+    }
+
+    // Floor to the closest millisecond
+    using Milli = std::chrono::duration<steady_clock::rep, std::milli>;
+    Milli milli = std::chrono::floor<Milli>(runTime);
+
+    using SecondsFloat = std::chrono::duration<double>;
+    SecondsFloat sec = std::chrono::duration_cast<SecondsFloat>(milli);
+
+    aResp->res.jsonValue["ServiceRootUptimeSeconds"] = sec.count();
+}
+
+inline void
+    managerGetServiceRootUptime(const std::shared_ptr<bmcweb::AsyncResp>& aResp)
+{
+    sdbusplus::asio::getProperty<uint64_t>(
+        *crow::connections::systemBus, "org.freedesktop.systemd1",
+        "/org/freedesktop/systemd1/unit/bmcweb_2eservice",
+        "org.freedesktop.systemd1.Unit", "ActiveEnterTimestampMonotonic",
+        std::bind_front(afterGetManagerStartTime, aResp));
+}
 /**
  * handleManagerDiagnosticData supports ManagerDiagnosticData.
  * It retrieves BMC health information from various DBus resources and returns
@@ -29,11 +76,13 @@ inline void handleManagerDiagnosticDataGet(
         return;
     }
     asyncResp->res.jsonValue["@odata.type"] =
-        "#ManagerDiagnosticData.v1_0_0.ManagerDiagnosticData";
+        "#ManagerDiagnosticData.v1_2_0.ManagerDiagnosticData";
     asyncResp->res.jsonValue["@odata.id"] =
         "/redfish/v1/Managers/bmc/ManagerDiagnosticData";
     asyncResp->res.jsonValue["Id"] = "ManagerDiagnosticData";
     asyncResp->res.jsonValue["Name"] = "Manager Diagnostic Data";
+
+    managerGetServiceRootUptime(asyncResp);
 }
 
 inline void requestRoutesManagerDiagnosticData(App& app)