EventLogger.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / cdf / src / WCF / SMDiagnostics / System / ServiceModel / Diagnostics / EventLogger.cs / 1305376 / EventLogger.cs
                        

                        
                            //------------------------------------------------------------ 
// Copyright (c) Microsoft Corporation.  All rights reserved.
//-----------------------------------------------------------

namespace System.ServiceModel.Diagnostics 
{
    using System.Collections.Generic; 
    using System.Diagnostics; 
    using System.Globalization;
    using System.Runtime; 
    using System.Runtime.CompilerServices;
    using System.Runtime.Diagnostics;
    using System.Runtime.InteropServices;
    using System.Runtime.Versioning; 
    using System.Security;
    using System.Security.Permissions; 
    using System.Security.Principal; 
    using System.Text;
 

    class EventLogger
    {
        [Fx.Tag.SecurityNote(Miscellaneous = "RequiresReview - In PT log no more than 5 events.")] 
        internal const int MaxEventLogsInPT = 5;
 
        DiagnosticTrace diagnosticTrace; 

        [Fx.Tag.SecurityNote(Critical = "Protect the string that defines the event source name.", 
            Safe = "It demands UnmanagedCode=true so PT cannot call.")]
        [SecurityCritical]
        string eventLogSourceName;
 
        bool isInPatialTrust = false;
 
        EventLogger() 
        {
            isInPatialTrust = IsInPartialTrust(); 
        }

        [Obsolete("For SMDiagnostics.dll use only. Call DiagnosticUtility.EventLog instead")]
        internal EventLogger(string eventLogSourceName, object diagnosticTrace) 
        {
            try 
            { 
                this.diagnosticTrace = (DiagnosticTrace)diagnosticTrace;
                //set diagnostics trace prior to calling SafeSetLogSourceName 
                if (canLogEvent)
                {
                    SafeSetLogSourceName(eventLogSourceName);
                } 
            }
            catch (SecurityException) 
            { 
                // running in PT, do not try to log events anymore
                canLogEvent = false; 
                // not throwing exception on purpose
            }
        }
 
        [Fx.Tag.SecurityNote(Critical = "Protect the string that defines the event source name.",
            Safe = "It demands UnmanagedCode=true so PT cannot call.")] 
        [SecuritySafeCritical] 
        [SecurityPermission(SecurityAction.Demand, UnmanagedCode = true)]
        void SafeSetLogSourceName(string eventLogSourceName) 
        {
            this.eventLogSourceName = eventLogSourceName;
        }
 
        [Fx.Tag.SecurityNote(Critical = "Sets event source name.")]
        [SecurityCritical] 
        void SetLogSourceName(string eventLogSourceName, object diagnosticTrace) 
        {
            this.eventLogSourceName = eventLogSourceName; 
            this.diagnosticTrace = (DiagnosticTrace)diagnosticTrace;
        }

        [Fx.Tag.SecurityNote(Critical = "Unsafe method to create event logger (sets the event source name).")] 
        [SecurityCritical]
        internal static EventLogger UnsafeCreateEventLogger(string eventLogSourceName, object diagnosticTrace) 
        { 
            EventLogger logger = new EventLogger();
            logger.SetLogSourceName(eventLogSourceName, diagnosticTrace); 
            return logger;
        }

        bool IsInPartialTrust() 
        {
            bool retval = false; 
            try 
            {
                using (Process process = Process.GetCurrentProcess()) 
                {
                    retval = string.IsNullOrEmpty(process.ProcessName);
                }
            } 
            catch (SecurityException)
            { 
                // we are just testing, ignore exception 
                retval = true;
            } 

            return retval;
        }
 

        // Converts incompatible serverity enumeration TraceEventType into EventLogEntryType 
        static EventLogEntryType EventLogEntryTypeFromEventType(TraceEventType type) 
        {
            EventLogEntryType retval = EventLogEntryType.Information; 
            switch (type)
            {
                case TraceEventType.Critical:
                case TraceEventType.Error: 
                    retval = EventLogEntryType.Error;
                    break; 
                case TraceEventType.Warning: 
                    retval = EventLogEntryType.Warning;
                    break; 
            }
            return retval;
        }
 
        static bool canLogEvent = true;
 
        internal void LogEvent(TraceEventType type, EventLogCategory category, EventLogEventId eventId, bool shouldTrace, params string[] values) 
        {
            if (canLogEvent) 
            {
                try
                {
                    SafeLogEvent(type, category, eventId, shouldTrace, values); 
                }
                catch (SecurityException ex) 
                { 
                    // running in PT, do not try to log events anymore
                    canLogEvent = false; 

                    // not throwing exception on purpose
                    if (shouldTrace && this.diagnosticTrace != null)
                    { 
                        this.diagnosticTrace.TraceEvent(TraceEventType.Warning, DiagnosticsTraceCode.TraceHandledException, DiagnosticTrace.GenerateMsdnTraceCode("System.ServiceModel.Diagnostics", "TraceHandledException"), TraceSR.GetString(TraceSR.TraceHandledException), null, ex, null);
                    } 
                } 
            }
        } 

        [Fx.Tag.SecurityNote(Critical = "Logs event to the event log by calling unsafe method.",
            Safe = "Demands the same permission that is asserted by the unsafe method.")]
        [SecuritySafeCritical] 
        [SecurityPermission(SecurityAction.Demand, UnmanagedCode = true)]
        internal void SafeLogEvent(TraceEventType type, EventLogCategory category, EventLogEventId eventId, bool shouldTrace, params string[] values) 
        { 

            UnsafeLogEvent(type, category, eventId, shouldTrace, values); 
        }

        [SecurityCritical]
        static int logCountForPT; 

#pragma warning disable 56500, 56523 
        [Fx.Tag.SecurityNote(Critical = "Logs event to the event log and asserts Unmanaged code.")] 
        [SecurityCritical]
        internal void UnsafeLogEvent(TraceEventType type, EventLogCategory category, EventLogEventId eventId, bool shouldTrace, params string[] values) 
        {
            if (logCountForPT < MaxEventLogsInPT)
            {
                try 
                {
                    // Vista introduces a new limitation:  a much smaller max 
                    // event log entry size that we need to track.  All strings cannot 
                    // exceed 31839 characters in length when totalled together.
                    // Choose a max length of 25600 characters (25k) to allow for 
                    // buffer since this max length may be reduced without warning.
                    const int MaxEventLogEntryLength = 25600;

                    int eventLogEntryLength = 0; 

                    string[] logValues = new string[values.Length + 2]; 
                    for (int i = 0; i < values.Length; ++i) 
                    {
                        string stringValue = values[i]; 
                        if (!string.IsNullOrEmpty(stringValue))
                        {
                            stringValue = NormalizeEventLogParameter(stringValue);
                        } 
                        else
                        { 
                            stringValue = String.Empty; 
                        }
 
                        logValues[i] = stringValue;
                        eventLogEntryLength += stringValue.Length + 1;
                    }
 
                    string normalizedProcessName = NormalizeEventLogParameter(UnsafeGetProcessName());
                    logValues[logValues.Length - 2] = normalizedProcessName; 
                    eventLogEntryLength += (normalizedProcessName.Length + 1); 

                    string invariantProcessId = UnsafeGetProcessId().ToString(CultureInfo.InvariantCulture); 
                    logValues[logValues.Length - 1] = invariantProcessId;
                    eventLogEntryLength += (invariantProcessId.Length + 1);

                    // If current event log entry length is greater than max length 
                    // need to truncate to max length.  This probably means that we
                    // have a very long exception and stack trace in our parameter 
                    // strings.  Truncate each string by MaxEventLogEntryLength 
                    // divided by number of strings in the entry.
                    // Truncation algorithm is overly aggressive by design to 
                    // simplify the code change due to Product Cycle timing.
                    if (eventLogEntryLength > MaxEventLogEntryLength)
                    {
                        // logValues.Length is always > 0 (minimum value = 2) 
                        // Subtract one to insure string ends in '\0'
                        int truncationLength = (MaxEventLogEntryLength / logValues.Length) - 1; 
 
                        for (int i = 0; i < logValues.Length; i++)
                        { 
                            if (logValues[i].Length > truncationLength)
                            {
                                logValues[i] = logValues[i].Substring(0, truncationLength);
                            } 
                        }
                    } 
 
                    SecurityIdentifier sid = WindowsIdentity.GetCurrent().User;
                    byte[] sidBA = new byte[sid.BinaryLength]; 
                    sid.GetBinaryForm(sidBA, 0);
                    IntPtr[] stringRoots = new IntPtr[logValues.Length];
                    GCHandle stringsRootHandle = new GCHandle();
                    GCHandle[] stringHandles = null; 

                    try 
                    { 
                        stringsRootHandle = GCHandle.Alloc(stringRoots, GCHandleType.Pinned);
                        stringHandles = new GCHandle[logValues.Length]; 
                        for (int strIndex = 0; strIndex < logValues.Length; strIndex++)
                        {
                            stringHandles[strIndex] = GCHandle.Alloc(logValues[strIndex], GCHandleType.Pinned);
                            stringRoots[strIndex] = stringHandles[strIndex].AddrOfPinnedObject(); 
                        }
                        UnsafeWriteEventLog(type, category, eventId, logValues, sidBA, stringsRootHandle); 
                    } 
                    finally
                    { 
                        if (stringsRootHandle.AddrOfPinnedObject() != IntPtr.Zero)
                        {
                            stringsRootHandle.Free();
                        } 
                        if (stringHandles != null)
                        { 
                            foreach (GCHandle gcHandle in stringHandles) 
                            {
                                if (gcHandle != null) 
                                {
                                    gcHandle.Free();
                                }
                            } 
                        }
                    } 
                    if (shouldTrace && this.diagnosticTrace != null) 
                    {
                        const int RequiredValueCount = 4; 
                        Dictionary eventValues = new Dictionary(logValues.Length + RequiredValueCount);
                        eventValues["CategoryID.Name"] = category.ToString();
                        eventValues["CategoryID.Value"] = ((uint)category).ToString(CultureInfo.InvariantCulture);
                        eventValues["InstanceID.Name"] = eventId.ToString(); 
                        eventValues["InstanceID.Value"] = ((uint)eventId).ToString(CultureInfo.InvariantCulture);
                        for (int i = 0; i < values.Length; ++i) 
                        { 
                            eventValues.Add("Value" + i.ToString(CultureInfo.InvariantCulture), values[i] == null ? string.Empty : System.Runtime.Diagnostics.DiagnosticTrace.XmlEncode(values[i]));
                        } 
                        this.diagnosticTrace.TraceEvent(type,
                            DiagnosticsTraceCode.EventLog, DiagnosticTrace.GenerateMsdnTraceCode("System.ServiceModel.Diagnostics", "EventLog"),
                            TraceSR.GetString(TraceSR.TraceCodeEventLog),
                            new DictionaryTraceRecord(eventValues), null, null); 
                    }
                } 
                catch (Exception e) 
                {
                    if (Fx.IsFatal(e)) 
                    {
                        throw;
                    }
                    // If not fatal, just eat the exception 
                }
                // In PT, we only limit 5 event logging per session 
                if (isInPatialTrust) 
                {
                    logCountForPT++; 
                }
            }
        }
 
        [SecurityCritical]
        [SecurityPermission(SecurityAction.Assert, UnmanagedCode = true)] 
        [ResourceConsumption(ResourceScope.Machine)] 
        private void UnsafeWriteEventLog(TraceEventType type, EventLogCategory category, EventLogEventId eventId, string[] logValues, byte[] sidBA, GCHandle stringsRootHandle)
        { 
            using (SafeEventLogWriteHandle handle = SafeEventLogWriteHandle.RegisterEventSource(null, this.eventLogSourceName))
            {
                if (handle != null)
                { 
                    HandleRef data = new HandleRef(handle, stringsRootHandle.AddrOfPinnedObject());
                    NativeMethods.ReportEvent( 
                         handle, 
                         (ushort)EventLogEntryTypeFromEventType(type),
                         (ushort)category, 
                         (uint)eventId,
                         sidBA,
                         (ushort)logValues.Length,
                         0, 
                         data,
                         null); 
                } 
            }
        } 
#pragma warning restore 56500, 56523

        [SecurityCritical]
        [SecurityPermission(SecurityAction.Assert, UnmanagedCode = true)] 
        [MethodImpl(MethodImplOptions.NoInlining)]
        private string UnsafeGetProcessName() 
        { 
            string retval = null;
            using (Process process = Process.GetCurrentProcess()) 
            {
                retval = process.ProcessName;
            }
            return retval; 
        }
 
        [SecurityCritical] 
        [SecurityPermission(SecurityAction.Assert, UnmanagedCode = true)]
        [MethodImpl(MethodImplOptions.NoInlining)] 
        private int UnsafeGetProcessId()
        {
            int retval = -1;
            using (Process process = Process.GetCurrentProcess()) 
            {
                retval = process.Id; 
            } 
            return retval;
        } 

        internal void LogEvent(TraceEventType type, EventLogCategory category, EventLogEventId eventId, params string[] values)
        {
            this.LogEvent(type, category, eventId, true, values); 
        }
 
        internal static string NormalizeEventLogParameter(string param) 
        {
            if (param.IndexOf('%') < 0) 
            {
                return param;
            }
 
            StringBuilder str = null;
            int len = param.Length; 
            for (int i = 0; i < len; ++i) 
            {
                char c = param[i]; 

                // Not '%'
                if (c != '%')
                { 
                    if (str != null) str.Append(c);
                    continue; 
                } 

                // Last char 
                if ((i + 1) >= len)
                {
                    if (str != null) str.Append(c);
                    continue; 
                }
 
                // Next char is not number 
                if (param[i + 1] < '0' || param[i + 1] > '9')
                { 
                    if (str != null) str.Append(c);
                    continue;
                }
 
                // initialize str builder
                if (str == null) 
                { 
                    str = new StringBuilder(len + 2);
                    for (int j = 0; j < i; ++j) 
                    {
                        str.Append(param[j]);
                    }
                } 
                str.Append(c);
                str.Append(' '); 
            } 

            return str != null ? str.ToString() : param; 
        }
    }
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.

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