CompressedStack.cs source code in C# .NET

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Code:

                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / clr / src / BCL / System / Threading / CompressedStack.cs / 1305376 / CompressedStack.cs
                        

                        
                            // ==++== 
//
//   Copyright (c) Microsoft Corporation.  All rights reserved.
//
// ==--== 
/*==============================================================================
** 
** Class: CompressedStack 
**
** [....] 
** [....]
**
** Purpose: Managed wrapper for the security stack compression implementation
** 
=============================================================================*/
 
namespace System.Threading 
{
    using System.Security; 
    using System.Security.Permissions;
    using System.Runtime.InteropServices;
    using System.Runtime.CompilerServices;
#if FEATURE_CORRUPTING_EXCEPTIONS 
    using System.Runtime.ExceptionServices;
#endif // FEATURE_CORRUPTING_EXCEPTIONS 
    using System.Runtime.ConstrainedExecution; 
    using System.Runtime.Versioning;
    using System.Reflection; 
    using System.Collections;
    using System.Threading;
    using System.Runtime.Serialization;
    using System.Diagnostics.Contracts; 

 
    internal struct CompressedStackSwitcher: IDisposable 
    {
        internal CompressedStack curr_CS; 
        internal CompressedStack prev_CS;
        internal IntPtr prev_ADStack;

 
        public override bool Equals(Object obj)
        { 
            if (obj == null || !(obj is CompressedStackSwitcher)) 
                return false;
            CompressedStackSwitcher sw = (CompressedStackSwitcher)obj; 
            return (this.curr_CS == sw.curr_CS && this.prev_CS == sw.prev_CS && this.prev_ADStack == sw.prev_ADStack);
        }

        public override int GetHashCode() 
        {
            return ToString().GetHashCode(); 
        } 

        public static bool operator ==(CompressedStackSwitcher c1, CompressedStackSwitcher c2) 
        {
            return c1.Equals(c2);
        }
 
        public static bool operator !=(CompressedStackSwitcher c1, CompressedStackSwitcher c2)
        { 
            return !c1.Equals(c2); 
        }
 
        [System.Security.SecuritySafeCritical] // overrides public transparent member
        public void Dispose()
        {
            Undo(); 
        }
 
        [System.Security.SecurityCritical]  // auto-generated 
        [ReliabilityContract(Consistency.WillNotCorruptState, Cer.MayFail)]
#if FEATURE_CORRUPTING_EXCEPTIONS 
        [HandleProcessCorruptedStateExceptions] //
#endif // FEATURE_CORRUPTING_EXCEPTIONS
        internal bool UndoNoThrow()
        { 
            try
            { 
                Undo(); 
            }
            catch 
            {
                return false;
            }
            return true; 
        }
 
 
        [System.Security.SecurityCritical]  // auto-generated
        [ReliabilityContract(Consistency.WillNotCorruptState, Cer.MayFail)] 
        public void Undo()
        {
            if (curr_CS == null && prev_CS == null)
                return; 
            if (prev_ADStack != (IntPtr)0)
                CompressedStack.RestoreAppDomainStack(prev_ADStack); 
            CompressedStack.SetCompressedStackThread(prev_CS); 

            prev_CS = null; 
            curr_CS = null;
            prev_ADStack = (IntPtr)0;
        }
    } 

     [System.Security.SecurityCritical]  // auto-generated 
     internal class SafeCompressedStackHandle : SafeHandle 
     {
        public SafeCompressedStackHandle() : base(IntPtr.Zero, true) 
        {
        }

        public override bool IsInvalid { 
            [System.Security.SecurityCritical]
            get { return handle == IntPtr.Zero; } 
        } 

        [System.Security.SecurityCritical] 
        override protected bool ReleaseHandle()
        {
            CompressedStack.DestroyDelayedCompressedStack(handle);
            handle = IntPtr.Zero; 
            return true;
        } 
     } 

 

     [Serializable]
    public sealed class CompressedStack:ISerializable
    { 

        private PermissionListSet m_pls; 
        [System.Security.SecurityCritical /*auto-generated*/] 
        private SafeCompressedStackHandle m_csHandle;
 

        internal PermissionListSet PLS
        {
            get 
            {
                return m_pls; 
            } 
        }
 
        [System.Security.SecurityCritical]  // auto-generated
        internal CompressedStack( SafeCompressedStackHandle csHandle )
        {
            m_csHandle = csHandle; 
        }
 
        [System.Security.SecurityCritical]  // auto-generated 
        private CompressedStack(SafeCompressedStackHandle csHandle, PermissionListSet pls)
        { 
            this.m_csHandle = csHandle;
            this.m_pls = pls;
        }
 
        [System.Security.SecurityCritical]  // auto-generated_required
        public void GetObjectData(SerializationInfo info, StreamingContext context) 
        { 
            if (info==null)
                throw new ArgumentNullException("info"); 
            Contract.EndContractBlock();
            CompleteConstruction(null);
            info.AddValue("PLS", this.m_pls);
        } 

        private CompressedStack(SerializationInfo info, StreamingContext context) 
        { 
            this.m_pls = (PermissionListSet)info.GetValue("PLS", typeof(PermissionListSet));
        } 

        internal SafeCompressedStackHandle CompressedStackHandle
        {
            [System.Security.SecurityCritical]  // auto-generated 
            [ReliabilityContract(Consistency.WillNotCorruptState, Cer.Success)]
            get 
            { 
                return m_csHandle;
            } 
            [System.Security.SecurityCritical]  // auto-generated
            [ReliabilityContract(Consistency.WillNotCorruptState, Cer.Success)]
            private set
            { 
                m_csHandle = value;
            } 
        } 

        [System.Security.SecurityCritical]  // auto-generated_required 
        [MethodImplAttribute(MethodImplOptions.NoInlining)] // Methods containing StackCrawlMark local var has to be marked non-inlineable
        public static CompressedStack GetCompressedStack()
        {
            // This is a Capture() 
            StackCrawlMark stackMark = StackCrawlMark.LookForMyCaller;
            return CompressedStack.GetCompressedStack(ref stackMark); 
        } 

        [System.Security.SecurityCritical]  // auto-generated 
        internal static CompressedStack GetCompressedStack(ref StackCrawlMark stackMark)
        {
            CompressedStack cs;
            CompressedStack innerCS = null; 
            if (CodeAccessSecurityEngine.QuickCheckForAllDemands())
            { 
                cs = new CompressedStack(null); 
            }
            else if (CodeAccessSecurityEngine.AllDomainsHomogeneousWithNoStackModifiers()) 
            {
                // if all AppDomains on the stack are homogeneous, we don't need to walk the stack
                // however, we do need to capture the AppDomain stack.
                cs = new CompressedStack(GetDelayedCompressedStack(ref stackMark, false)); 
                cs.m_pls = PermissionListSet.CreateCompressedState_HG();
            } 
            else 
            {
                // regular stackwalking case 
                // We want this to complete without ThreadAborts - if we're in a multiple AD callstack and an intermediate AD gets unloaded,
                // preventing TAs here prevents a race condition where a SafeCompressedStackHandle is created to a DCS belonging to an AD that's
                // gone away
                cs = new CompressedStack(null); 
                RuntimeHelpers.PrepareConstrainedRegions();
                try 
                { 
                    // Empty try block to ensure no ThreadAborts in the finally block
                } 
                finally
                {

                    cs.CompressedStackHandle = GetDelayedCompressedStack(ref stackMark, true); 
                    if (cs.CompressedStackHandle != null && IsImmediateCompletionCandidate(cs.CompressedStackHandle, out innerCS))
                    { 
                        try 
                        {
                            cs.CompleteConstruction(innerCS); 
                        }
                        finally
                        {
                            DestroyDCSList(cs.CompressedStackHandle); 
                        }
                    } 
                } 
            }
            return cs; 
        }

        [System.Security.SecuritySafeCritical]  // auto-generated
        [MethodImplAttribute(MethodImplOptions.NoInlining)] // Methods containing StackCrawlMark local var has to be marked non-inlineable 
        public static CompressedStack Capture()
        { 
            StackCrawlMark stackMark = StackCrawlMark.LookForMyCaller; 
            return GetCompressedStack(ref stackMark);
        } 

        // This method is special from a security perspective - the VM will not allow a stack walk to
        // continue past the call to CompressedStack.Run.  If you change the signature to this method, or
        // provide an alternate way to do a CompressedStack.Run make sure to update 
        // SecurityStackWalk::IsSpecialRunFrame in the VM to search for the new method.
        [System.Security.SecurityCritical]  // auto-generated_required 
        [DynamicSecurityMethodAttribute()] 
        public static void Run(CompressedStack compressedStack, ContextCallback callback, Object state)
        { 

            if (compressedStack == null )
            {
                throw new ArgumentException(Environment.GetResourceString("Arg_NamedParamNull"),"compressedStack"); 
            }
            Contract.EndContractBlock(); 
            if (cleanupCode == null) 
            {
                tryCode = new RuntimeHelpers.TryCode(runTryCode); 
                cleanupCode = new RuntimeHelpers.CleanupCode(runFinallyCode);
            }

            CompressedStackRunData runData = new CompressedStackRunData(compressedStack, callback, state); 
            RuntimeHelpers.ExecuteCodeWithGuaranteedCleanup(tryCode, cleanupCode, runData);
        } 
 
        internal class CompressedStackRunData
        { 
            internal CompressedStack cs;
            internal ContextCallback callBack;
            internal Object state;
            internal CompressedStackSwitcher cssw; 
            internal CompressedStackRunData(CompressedStack cs, ContextCallback cb, Object state)
            { 
                this.cs = cs; 
                this.callBack = cb;
                this.state = state; 
                this.cssw = new CompressedStackSwitcher();
            }
        }
        [System.Security.SecurityCritical]  // auto-generated 
        static internal void runTryCode(Object userData)
        { 
            CompressedStackRunData rData = (CompressedStackRunData) userData; 
            rData.cssw = SetCompressedStack(rData.cs, GetCompressedStackThread());
            rData.callBack(rData.state); 

        }

        [System.Security.SecurityCritical]  // auto-generated 
        [PrePrepareMethod]
        static internal void runFinallyCode(Object userData, bool exceptionThrown) 
        { 
            CompressedStackRunData rData = (CompressedStackRunData) userData;
            rData.cssw.Undo(); 
        }

        static internal RuntimeHelpers.TryCode tryCode;
        static internal RuntimeHelpers.CleanupCode cleanupCode; 

 
        [System.Security.SecurityCritical]  // auto-generated 
#if FEATURE_CORRUPTING_EXCEPTIONS
        [HandleProcessCorruptedStateExceptions] // 
#endif // FEATURE_CORRUPTING_EXCEPTIONS
        internal static CompressedStackSwitcher SetCompressedStack(CompressedStack cs, CompressedStack prevCS)
        {
            CompressedStackSwitcher cssw = new CompressedStackSwitcher(); 
            RuntimeHelpers.PrepareConstrainedRegions();
            try 
            { 
                // Order is important in this block.
                // Also, we dont want any THreadAborts happening when we try to set it 
                RuntimeHelpers.PrepareConstrainedRegions();
                try
                {
                    // Empty try block to ensure no ThreadAborts in the finally block 
                }
                finally 
                { 
                    // SetCompressedStackThread can throw - only if it suceeds we shd update the switcher and overrides
                    SetCompressedStackThread(cs); 
                    cssw.prev_CS = prevCS;
                    cssw.curr_CS = cs;
                    cssw.prev_ADStack = SetAppDomainStack(cs);
                } 
            }
            catch 
            { 
                cssw.UndoNoThrow();
                throw; // throw the original exception 
            }
            return cssw;
        }
 

        [System.Security.SecuritySafeCritical]  // auto-generated 
        [ComVisible(false)] 
        public CompressedStack CreateCopy()
        { 
            return new CompressedStack(this.m_csHandle, this.m_pls);
        }

        [System.Security.SecurityCritical]  // auto-generated 
        [ReliabilityContract(Consistency.WillNotCorruptState, Cer.Success)]
        internal static IntPtr SetAppDomainStack(CompressedStack cs) 
        { 
            //Update the AD Stack on the thread and return the previous AD Stack
            return Thread.CurrentThread.SetAppDomainStack((cs == null ? null:cs.CompressedStackHandle)); 
        }


        [System.Security.SecurityCritical]  // auto-generated 
        [ReliabilityContract(Consistency.WillNotCorruptState, Cer.Success)]
        internal static void RestoreAppDomainStack(IntPtr appDomainStack) 
        { 
            Thread.CurrentThread.RestoreAppDomainStack(appDomainStack); //Restore the previous AD Stack
        } 
        internal static CompressedStack GetCompressedStackThread()
        {
            ExecutionContext ec = Thread.CurrentThread.GetExecutionContextNoCreate();
            if (ec != null && ec.SecurityContext != null) 
                return ec.SecurityContext.CompressedStack;
            return null; 
        } 
        [ReliabilityContract(Consistency.WillNotCorruptState, Cer.MayFail)]
        internal static void SetCompressedStackThread(CompressedStack cs) 
        {
            ExecutionContext ec = Thread.CurrentThread.ExecutionContext;
            if (ec.SecurityContext != null)
                ec.SecurityContext.CompressedStack = cs; 
            else if (cs != null)
            { 
                SecurityContext sc = new SecurityContext(); 
                sc.CompressedStack = cs;
                ec.SecurityContext = sc; 
            }
        }

 
        [System.Security.SecurityCritical]  // auto-generated
        internal bool CheckDemand(CodeAccessPermission demand, PermissionToken permToken, RuntimeMethodHandleInternal rmh) 
        { 
            CompleteConstruction(null);
 
            if (PLS == null)
                return SecurityRuntime.StackHalt;
            else
                return PLS.CheckDemand(demand, permToken, rmh); 

        } 
 
        [System.Security.SecurityCritical]  // auto-generated
        internal bool CheckSetDemand(PermissionSet pset , RuntimeMethodHandleInternal rmh) 
        {
            CompleteConstruction(null);

            if (PLS == null) 
                return SecurityRuntime.StackHalt;
            else 
                return PLS.CheckSetDemand(pset, rmh); 
        }
 
        /// 
        ///     Demand which succeeds if either a set of special permissions or a permission set is granted
        ///     to the call stack
        ///  
        /// set of flags to check (See PermissionType)
        /// alternate permission set to check 
        [System.Security.SecurityCritical]  // auto-generated 
        internal void DemandFlagsOrGrantSet(int flags, PermissionSet grantSet)
        { 
            CompleteConstruction(null);
            if (PLS == null)
                return;
 
            PLS.DemandFlagsOrGrantSet(flags, grantSet);
        } 
 
        [System.Security.SecurityCritical]  // auto-generated
        internal void GetZoneAndOrigin(ArrayList zoneList, ArrayList originList, PermissionToken zoneToken, PermissionToken originToken) 
        {
            CompleteConstruction(null);
            if (PLS != null)
                PLS.GetZoneAndOrigin(zoneList,originList,zoneToken,originToken); 
            return;
        } 
 
        [System.Security.SecurityCritical]  // auto-generated
        [ReliabilityContract(Consistency.WillNotCorruptState, Cer.MayFail)] 
        internal void CompleteConstruction(CompressedStack innerCS)
        {
            if (PLS != null)
                return; 
            PermissionListSet pls = PermissionListSet.CreateCompressedState(this, innerCS);
            lock (this) 
            { 
                if (PLS == null)
                    m_pls = pls; 
            }
        }
        [System.Security.SecurityCritical]  // auto-generated
        [ResourceExposure(ResourceScope.None)] 
        [MethodImplAttribute(MethodImplOptions.InternalCall)]
        [ReliabilityContract(Consistency.WillNotCorruptState, Cer.MayFail)] 
        internal extern static SafeCompressedStackHandle GetDelayedCompressedStack(ref StackCrawlMark stackMark, 
                                                                                   bool walkStack);
 
        [System.Security.SecurityCritical]  // auto-generated
        [ResourceExposure(ResourceScope.None)]
        [MethodImplAttribute(MethodImplOptions.InternalCall)]
        internal extern static void DestroyDelayedCompressedStack( IntPtr unmanagedCompressedStack ); 

    [System.Security.SecurityCritical]  // auto-generated 
    [ResourceExposure(ResourceScope.None)] 
        [MethodImplAttribute(MethodImplOptions.InternalCall)]
        [ReliabilityContract(Consistency.WillNotCorruptState, Cer.Success)] 
        internal extern static void DestroyDCSList( SafeCompressedStackHandle compressedStack );


        [System.Security.SecurityCritical]  // auto-generated 
        [ResourceExposure(ResourceScope.None)]
        [MethodImplAttribute(MethodImplOptions.InternalCall)] 
        internal extern static int GetDCSCount(SafeCompressedStackHandle compressedStack); 

        [System.Security.SecurityCritical]  // auto-generated 
        [ResourceExposure(ResourceScope.None)]
        [MethodImplAttribute(MethodImplOptions.InternalCall)]
        [ReliabilityContract(Consistency.WillNotCorruptState, Cer.Success)]
        internal extern static bool IsImmediateCompletionCandidate(SafeCompressedStackHandle compressedStack, out CompressedStack innerCS); 

        [System.Security.SecurityCritical]  // auto-generated 
        [ResourceExposure(ResourceScope.None)] 
        [MethodImplAttribute(MethodImplOptions.InternalCall)]
        internal extern static DomainCompressedStack GetDomainCompressedStack(SafeCompressedStackHandle compressedStack, int index); 

        [System.Security.SecurityCritical]  // auto-generated
        [ResourceExposure(ResourceScope.None)]
        [MethodImplAttribute(MethodImplOptions.InternalCall)] 
        internal extern static void GetHomogeneousPLS(PermissionListSet hgPLS);
 
 
    }
 
    //*********************************************************
    // New Implementation of CompressedStack creation/demand eval - NewCompressedStack/DomainCompressedStack
    //*********************************************************
    [Serializable] 
    internal sealed class DomainCompressedStack
    { 
        // Managed equivalent of DomainCompressedStack - used to perform demand evaluation 
        private PermissionListSet m_pls;
        // Did we terminate construction on this DCS and therefore, should we terminate construction on the rest of the CS? 
        private bool m_bHaltConstruction;


        // CompresedStack interacts with this class purely through the three properties marked internal 
        // Zone, Origin, AGRList.
        internal PermissionListSet PLS 
        { 
            get
            { 
                 return m_pls;
            }
        }
 
        internal bool ConstructionHalted
        { 
            get 
            {
                 return m_bHaltConstruction; 
            }
        }

 

        // Called from the VM only. 
        [System.Security.SecurityCritical]  // auto-generated 
        private static DomainCompressedStack CreateManagedObject(IntPtr unmanagedDCS)
        { 
            DomainCompressedStack newDCS = new DomainCompressedStack();
            newDCS.m_pls = PermissionListSet.CreateCompressedState(unmanagedDCS, out newDCS.m_bHaltConstruction);
            // return the created object
            return newDCS; 
        }
 
        [System.Security.SecurityCritical]  // auto-generated 
        [ResourceExposure(ResourceScope.None)]
        [MethodImplAttribute(MethodImplOptions.InternalCall)] 
        internal extern static int GetDescCount(IntPtr dcs);

        [System.Security.SecurityCritical]  // auto-generated
        [ResourceExposure(ResourceScope.None)] 
        [MethodImplAttribute(MethodImplOptions.InternalCall)]
        internal extern static void GetDomainPermissionSets(IntPtr dcs, out PermissionSet granted, out PermissionSet refused); 
 
        // returns true if the descriptor is a FrameSecurityDescriptor
        [System.Security.SecurityCritical]  // auto-generated 
        [ResourceExposure(ResourceScope.None)]
        [MethodImplAttribute(MethodImplOptions.InternalCall)]
        internal extern static bool GetDescriptorInfo(IntPtr dcs, int index, out PermissionSet granted, out PermissionSet refused, out Assembly assembly, out FrameSecurityDescriptor fsd);
 
        [System.Security.SecurityCritical]  // auto-generated
        [ResourceExposure(ResourceScope.None)] 
        [MethodImplAttribute(MethodImplOptions.InternalCall)] 
        internal extern static bool IgnoreDomain(IntPtr dcs);
    } 

}

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

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