Configure event log name and fallback on failure to read (oshi#1045)

MR-Os1 · Nov 14, 2019 · 9325493 · 9325493
1 parent 6823af1
commit 9325493
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Showing 2 changed files with 73 additions and 19 deletions.
diff --git a/oshi-core/src/main/java/oshi/software/os/windows/WindowsOperatingSystem.java b/oshi-core/src/main/java/oshi/software/os/windows/WindowsOperatingSystem.java
@@ -26,6 +26,7 @@
 import static oshi.software.os.OSService.State.OTHER;
 import static oshi.software.os.OSService.State.RUNNING;
 import static oshi.software.os.OSService.State.STOPPED;
+import static oshi.util.Memoizer.memoize;
 
 import java.io.File;
 import java.util.ArrayList;
@@ -36,6 +37,8 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
+import java.util.concurrent.TimeUnit;
+import java.util.function.Supplier;
 
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -86,6 +89,7 @@
 import oshi.software.os.OSService;
 import oshi.software.os.OSService.State;
 import oshi.software.os.OperatingSystem;
+import oshi.util.GlobalConfig;
 import oshi.util.ParseUtil;
 import oshi.util.platform.windows.PerfCounterQuery;
 import oshi.util.platform.windows.PerfCounterWildcardQuery;
@@ -100,6 +104,12 @@ public class WindowsOperatingSystem extends AbstractOperatingSystem {
     private static final boolean IS_VISTA_OR_GREATER = VersionHelpers.IsWindowsVistaOrGreater();
     private static final boolean IS_WINDOWS7_OR_GREATER = VersionHelpers.IsWindows7OrGreater();
 
+    /**
+     * Windows event log name
+     */
+    private static Supplier<String> systemLog = memoize(WindowsOperatingSystem::querySystemLog,
+            TimeUnit.HOURS.toNanos(1));
+
     private static final long BOOTTIME = querySystemBootTime();
 
     private static final HkeyPerformanceData HKEY_PERFORMANCE_DATA;
@@ -639,30 +649,41 @@ public long getSystemBootTime() {
     }
 
     private static long querySystemBootTime() {
-        // Get the most recent boot event (ID 12) from the Event log. If Windows "Fast
-        // Startup" is enabled we may not see event 12, so also check for most recent ID
-        // 6005 (Event log startup) as a reasonably close backup.
-        long event6005Time = 0L;
-        EventLogIterator iter = new EventLogIterator(null, "System", WinNT.EVENTLOG_BACKWARDS_READ);
-        while (iter.hasNext()) {
-            EventLogRecord record = iter.next();
-            if (record.getStatusCode() == 12) {
-                // Event 12 is system boot. We want this value unless we find two 6005 events
-                // first (may occur with Fast Boot)
-                return record.getRecord().TimeGenerated.longValue();
-            } else if (record.getStatusCode() == 6005) {
-                // If we already found one, this means we've found a second one without finding
-                // an event 12. Return the latest one.
+        String eventLog = systemLog.get();
+        if (eventLog != null) {
+            try {
+                EventLogIterator iter = new EventLogIterator(null, eventLog, WinNT.EVENTLOG_BACKWARDS_READ);
+                // Get the most recent boot event (ID 12) from the Event log. If Windows "Fast
+                // Startup" is enabled we may not see event 12, so also check for most recent ID
+                // 6005 (Event log startup) as a reasonably close backup.
+                long event6005Time = 0L;
+                while (iter.hasNext()) {
+                    EventLogRecord record = iter.next();
+                    if (record.getStatusCode() == 12) {
+                        // Event 12 is system boot. We want this value unless we find two 6005 events
+                        // first (may occur with Fast Boot)
+                        return record.getRecord().TimeGenerated.longValue();
+                    } else if (record.getStatusCode() == 6005) {
+                        // If we already found one, this means we've found a second one without finding
+                        // an event 12. Return the latest one.
+                        if (event6005Time > 0) {
+                            return event6005Time;
+                        }
+                        // First 6005; tentatively assign
+                        event6005Time = record.getRecord().TimeGenerated.longValue();
+                    }
+                }
+                // Only one 6005 found, return
                 if (event6005Time > 0) {
                     return event6005Time;
                 }
-                // First 6005; tentatively assign
-                event6005Time = record.getRecord().TimeGenerated.longValue();
+            } catch (Win32Exception e) {
+                LOG.warn("Can't open event log \"{}\".", eventLog);
             }
         }
-        // If we get this far, event log reading has failed. Subtract up time from
-        // current time as a reasonable proxy.
-        return event6005Time > 0 ? event6005Time : System.currentTimeMillis() / 1000L - querySystemUptime();
+        // If we get this far, event log reading has failed, either from no log or no
+        // startup times. Subtract up time from current time as a reasonable proxy.
+        return System.currentTimeMillis() / 1000L - querySystemUptime();
     }
 
     @Override
@@ -728,6 +749,22 @@ public OSService[] getServices() {
         }
     }
 
+    private static String querySystemLog() {
+        String systemLog = GlobalConfig.get("oshi.os.windows.eventlog", "System");
+        if (systemLog.isEmpty()) {
+            // Use faster boot time approximation
+            return null;
+        }
+        // Check whether it works
+        HANDLE h = Advapi32.INSTANCE.OpenEventLog(null, systemLog);
+        if (h == null) {
+            LOG.warn("Unable to open configured system Event log \"{}\". Calculating boot time from uptime.",
+                    systemLog);
+            return null;
+        }
+        return systemLog;
+    }
+
     enum OSVersionProperty {
         Version, ProductType, BuildNumber, CSDVersion, SuiteMask;
     }

diff --git a/oshi-core/src/main/resources/oshi.properties b/oshi-core/src/main/resources/oshi.properties
@@ -29,6 +29,23 @@ oshi.util.proc.path=/proc
 # Default is -1, no timeout
 oshi.util.wmi.timeout=-1
 
+# The name of the System event log containing bootup event IDs 12 and 6005. If a 
+# non-empty invalid log name is specified, the name "Application" will be used.
+#
+# This is used for a one-time calculation of system boot time that should be
+# consistent across process runs regardless of sleep/hibernate cycles, at 
+# the small cost of ~250ms latency reading upon WindowsOperatingSystem
+# initialization. 
+#
+# If the specified log is the empty string, or doesn't contain a bootup event,
+# boot time will be calculated by subtracting up time from current time. This 
+# may vary by up to a millisecond between program executions and does not 
+# properly account for sleep/hibernate cycles, but is fast and may be preferred 
+# if only approximate boot time is desired.
+#
+# Default is System
+oshi.os.windows.eventlog=System
+
 # Memoizer default expiration in milliseconds (return values will be cached this long)
 # Must be positive (negative value will never refresh)
 # Should be less than 1 second