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8983ce95a2
Pipes can be created with invalid characters in their names (such as `|`). This results in an exception being thrown when those files are accessed via standard API calls such as `Directory.GetFiles`. Other processes might create these pipes and inadvertently prevent XenCenter from starting altogether. Signed-off-by: Danilo Del Busso <danilo.delbusso@cloud.com>
456 lines
20 KiB
C#
456 lines
20 KiB
C#
/* Copyright (c) Cloud Software Group, Inc.
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*
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* Redistribution and use in source and binary forms,
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* with or without modification, are permitted provided
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* that the following conditions are met:
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*
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* * Redistributions of source code must retain the above
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* copyright notice, this list of conditions and the
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* following disclaimer.
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* * Redistributions in binary form must reproduce the above
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* copyright notice, this list of conditions and the
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* following disclaimer in the documentation and/or other
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* materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
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* CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
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* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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using System;
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using System.ComponentModel;
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using System.IO;
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using System.Linq;
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using System.Runtime.InteropServices;
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using System.Text;
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using System.Threading;
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namespace XenCenterLib
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{
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public class NamedPipes
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{
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[Flags]
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public enum FileAccess : uint
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{
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GenericRead = 0x80000000,
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GenericWrite = 0x40000000,
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GenericExecute = 0x20000000,
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GenericAll = 0x10000000
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}
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[Flags]
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public enum FileShare : uint
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{
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None = 0x00000000,
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/// <summary>
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/// Enables subsequent open operations on an object to request read access.
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/// Otherwise, other processes cannot open the object if they request read access.
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/// If this flag is not specified, but the object has been opened for read access, the function fails.
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/// </summary>
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Read = 0x00000001,
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/// <summary>
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/// Enables subsequent open operations on an object to request write access.
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/// Otherwise, other processes cannot open the object if they request write access.
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/// If this flag is not specified, but the object has been opened for write access, the function fails.
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/// </summary>
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Write = 0x00000002,
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/// <summary>
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/// Enables subsequent open operations on an object to request delete access.
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/// Otherwise, other processes cannot open the object if they request delete access.
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/// If this flag is not specified, but the object has been opened for delete access, the function fails.
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/// </summary>
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Delete = 0x00000004
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}
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public enum FileMode : uint
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{
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/// <summary>
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/// Creates a new file. The function fails if a specified file exists.
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/// </summary>
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CreateNew = 1,
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/// <summary>
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/// Creates a new file, always.
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/// If a file exists, the function overwrites the file, clears the existing attributes, combines the specified file attributes,
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/// and flags with FILE_ATTRIBUTE_ARCHIVE, but does not set the security descriptor that the SECURITY_ATTRIBUTES structure specifies.
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/// </summary>
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CreateAlways = 2,
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/// <summary>
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/// Opens a file. The function fails if the file does not exist.
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/// </summary>
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OpenExisting = 3,
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/// <summary>
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/// Opens a file, always.
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/// If a file does not exist, the function creates a file as if dwCreationDisposition is CREATE_NEW.
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/// </summary>
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OpenAlways = 4,
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/// <summary>
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/// Opens a file and truncates it so that its size is 0 (zero) bytes. The function fails if the file does not exist.
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/// The calling process must open the file with the GENERIC_WRITE access right.
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/// </summary>
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TruncateExisting = 5
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}
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[Flags]
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public enum FileAttributes : uint
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{
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Readonly = 0x00000001,
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Hidden = 0x00000002,
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System = 0x00000004,
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Directory = 0x00000010,
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Archive = 0x00000020,
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Device = 0x00000040,
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Normal = 0x00000080,
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Temporary = 0x00000100,
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SparseFile = 0x00000200,
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ReparsePoint = 0x00000400,
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Compressed = 0x00000800,
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Offline = 0x00001000,
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NotContentIndexed = 0x00002000,
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Encrypted = 0x00004000,
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Write_Through = 0x80000000,
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Overlapped = 0x40000000,
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NoBuffering = 0x20000000,
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RandomAccess = 0x10000000,
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SequentialScan = 0x08000000,
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DeleteOnClose = 0x04000000,
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BackupSemantics = 0x02000000,
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PosixSemantics = 0x01000000,
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OpenReparsePoint = 0x00200000,
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OpenNoRecall = 0x00100000,
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FirstPipeInstance = 0x00080000
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}
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/// <summary>
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/// Duplex pipe access.
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/// </summary>
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private const uint PIPE_ACCESS_DUPLEX = 0x00000003;
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/// <summary>
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/// Pipe blocking mode.
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/// </summary>
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private const uint PIPE_WAIT = 0x00000000;
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/// <summary>
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/// Pipe read mode of type Message.
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/// </summary>
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private const uint PIPE_READMODE_MESSAGE = 0x00000002;
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/// <summary>
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/// Message pipe type.
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/// </summary>
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private const uint PIPE_TYPE_MESSAGE = 0x00000004;
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/// <summary>
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/// Unlimited server pipe instances.
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/// </summary>
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private const uint PIPE_UNLIMITED_INSTANCES = 255;
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/// <summary>
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/// Waits indefinitely when connecting to a pipe.
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/// </summary>
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private const uint NMPWAIT_WAIT_FOREVER = 0xffffffff;
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/// <summary>
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/// Invalid operating system handle.
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/// </summary>
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private const int INVALID_HANDLE_VALUE = -1;
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/// <summary>
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/// More data is available.
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/// </summary>
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private const int ERROR_MORE_DATA = 234;
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/// <summary>
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/// There is a process on other end of the pipe.
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/// </summary>
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private const int ERROR_PIPE_CONNECTED = 535;
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[DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
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private static extern IntPtr CreateNamedPipe(String pipeName, uint openMode, uint pipeMode,
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uint maxInstances, uint outputBufferSize, uint inputBufferSize, uint timeoutInterval,
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IntPtr pipeSecurityDescriptor);
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/// <summary>
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/// Enables a named pipe server process to wait for a client
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/// process to connect to an instance of a named pipe.
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/// </summary>
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/// <param name="hHandle">Handle to the server end of a named pipe instance.</param>
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/// <param name="lpOverlapped">Pointer to an
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/// <see cref="AppModule.NamedPipes.Overlapped">Overlapped</see> object.</param>
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/// <returns>If the function succeeds, the return value is nonzero.</returns>
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[DllImport("kernel32.dll", SetLastError = true)]
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[return: MarshalAs(UnmanagedType.Bool)]
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private static extern bool ConnectNamedPipe(IntPtr namedPipeHandle, ref NativeOverlapped overlapped);
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/// <summary>
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/// Disconnects the server end of a named pipe instance from a client process.
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/// </summary>
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/// <param name="hHandle">Handle to an instance of a named pipe.</param>
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/// <returns>If the function succeeds, the return value is nonzero.</returns>
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[DllImport("kernel32.dll", SetLastError = true)]
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[return: MarshalAs(UnmanagedType.Bool)]
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private static extern bool DisconnectNamedPipe(IntPtr hHandle);
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/// <summary>
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/// Reads data from a file, starting at the position indicated by the file pointer.
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/// </summary>
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/// <param name="hHandle">Handle to the file to be read.</param>
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/// <param name="lpBuffer">Pointer to the buffer that receives the data read from the file.</param>
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/// <param name="nNumberOfBytesToRead">Number of bytes to be read from the file.</param>
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/// <param name="lpNumberOfBytesRead">Pointer to the variable that receives the number of bytes read.</param>
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/// <param name="lpOverlapped">Pointer to an
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/// <see cref="AppModule.NamedPipes.Overlapped">Overlapped</see> object.</param>
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/// <returns>The ReadFile function returns when one of the following
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/// conditions is met: a write operation completes on the write end of
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/// the pipe, the number of bytes requested has been read, or an error occurs.</returns>
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[DllImport("kernel32.dll", SetLastError = true)]
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[return: MarshalAs(UnmanagedType.Bool)]
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private static extern bool ReadFile(IntPtr fileHandle, [Out] byte[] dataBuffer, uint nNumberOfBytesToRead,
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out uint lpNumberOfBytesRead, [In] ref NativeOverlapped overlapped);
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[DllImport("kernel32.dll", SetLastError = true)]
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private static extern bool WriteFile(IntPtr fileHandle, [Out] byte[] dataBuffer, uint nNumberOfBytesToWrite,
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out uint lpNumberOfBytesWritten, [In] ref NativeOverlapped overlapped);
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[DllImport("kernel32.dll", SetLastError = true)]
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private static extern bool PeekNamedPipe(IntPtr handle, [Out] byte[] buffer, uint nBufferSize,
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out uint bytesRead, out uint bytesAvail, out uint BytesLeftThisMessage);
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[DllImport("kernel32.dll")]
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private static extern bool CallNamedPipe(string lpNamedPipeName, byte[] lpInBuffer,
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uint nInBufferSize, [Out] byte[] lpOutBuffer, uint nOutBufferSize,
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out uint lpBytesRead, uint nTimeOut);
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[DllImport("kernel32.dll", SetLastError = true)]
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[return: MarshalAs(UnmanagedType.Bool)]
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private static extern bool CloseHandle(IntPtr hObject);
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private const string STOP_LISTENING_MSG = "stop-listening-on-pipe";
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private const uint PIPE_CALL_TIMEOUT = 30 * 1000; //30sec
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public class Pipe
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{
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private static readonly log4net.ILog log = log4net.LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType);
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private readonly IntPtr Handle;
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private Thread pipeThread;
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private readonly string pipePath;
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private volatile bool run;
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public event Action<string> Read;
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public Pipe(string path)
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{
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pipePath = path;
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Handle = CreateNamedPipe(pipePath, PIPE_ACCESS_DUPLEX,
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PIPE_TYPE_MESSAGE | PIPE_READMODE_MESSAGE | PIPE_WAIT,
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PIPE_UNLIMITED_INSTANCES, 512, 512, NMPWAIT_WAIT_FOREVER, IntPtr.Zero);
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if (Handle.ToInt32() == INVALID_HANDLE_VALUE)
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log.Error($"Creating named pipe {path} failed.", new Win32Exception());
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else
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log.Info($"Successfully created named pipe '{path}'.");
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}
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public static bool ExistsPipe(string pipePath)
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{
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log.Debug($"Checking {pipePath} exists");
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// CA-382850: We iterate manually in order to catch ArgumentExceptions
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// when listing files. Pipes can be created with invalid characters in
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// their names. This throws exception when those files are accessed.
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// Other processes might create these pipes and inadvertently prevent
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// XenCenter from starting
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var e = Directory.EnumerateFiles(@"\\.\pipe\");
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using (var enumerator = e.GetEnumerator())
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{
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while (true)
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{
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try
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{
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if (!enumerator.MoveNext())
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{
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break;
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}
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if (enumerator.Current != null && enumerator.Current.Contains(pipePath))
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{
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return true;
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}
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}
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catch (ArgumentException)
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{
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// ignore, the pipe's name contains invalid characters
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}
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}
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}
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return false;
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}
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/// <summary>
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/// Send a message to the pipe with the given path. May block for up to PIPE_CALL_TIMEOUT milliseconds.
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/// </summary>
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public static void SendMessageToPipe(string pipePath, string message)
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{
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byte[] msg = Encoding.Unicode.GetBytes(message);
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byte[] rcv = Array.Empty<byte>();
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var success = CallNamedPipe(pipePath, msg, (uint)msg.Length, rcv, (uint)rcv.Length, out _, PIPE_CALL_TIMEOUT);
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if (success)
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log.Debug($"Message successfully forwarded to {pipePath})");
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else
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log.Error($"Failed to forward message to {pipePath} with native error code {new Win32Exception().NativeErrorCode}");
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}
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/// <summary>
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/// Starts reading from this pipe on a new background thread. This call returns immediately.
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/// Whenever data is read from the pipe, the Read event is fired.
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/// </summary>
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public void BeginRead()
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{
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if (pipeThread == null)
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{
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run = true;
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pipeThread = new Thread(BackgroundPipeThread) { Name = "Named pipe thread", IsBackground = true };
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pipeThread.Start();
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}
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}
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/// <summary>
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/// Stops reading from this pipe. May block for up to PIPE_CALL_TIMEOUT milliseconds.
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/// </summary>
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public void EndRead()
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{
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SendMessageToPipe(pipePath, STOP_LISTENING_MSG);
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}
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private void BackgroundPipeThread()
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{
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while (run)
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{
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try
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{
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NativeOverlapped overlapped = new NativeOverlapped();
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if (!ConnectNamedPipe(Handle, ref overlapped))
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{
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Win32Exception exn = new Win32Exception();
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if (exn.NativeErrorCode == ERROR_PIPE_CONNECTED)
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log.Debug("A remote process has already connected to the named pipe since we called CreateNamedPipe.");
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else
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throw new Win32Exception("ConnectNamedPipe failed", exn);
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}
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ProcessPipeMessage();
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if (!DisconnectNamedPipe(Handle))
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throw new Win32Exception("DisconnectNamedPipe failed", new Win32Exception());
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}
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catch (Exception exn)
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{
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log.Error("Error in named pipe thread.", exn);
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// Sanity: pause after errors to prevent massive log spamming/CPU drain
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// in the event of an infinite error loop
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Thread.Sleep(1000);
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}
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}
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// Close pipe handle to destroy it
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if (CloseHandle(Handle))
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log.Debug("Closed NamedPipe handle");
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else
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log.Warn("CloseHandle() in NamedPipes failed", new Win32Exception());
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log.Debug("NamedPipe thread exited");
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}
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private void ProcessPipeMessage()
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{
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NativeOverlapped overlapped = new NativeOverlapped();
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byte[] readMessage;
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using (MemoryStream ms = new MemoryStream())
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{
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while (true)
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{
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// Loop as follows:
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// Peek at the pipe to see how much data is available
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// Read the data and append it to the buffer
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// If we get ERROR_MORE_DATA, repeat
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// First peek into the pipe to see how much data is waiting.
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byte[] peekBuf = Array.Empty<byte>();
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if (!PeekNamedPipe(Handle, peekBuf, (uint)peekBuf.Length, out var bytesRead, out var bytesAvailable, out var bytesLeft))
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{
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throw new Win32Exception(
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string.Format("PeekNamedPipe failed. bytesRead={0} bytesAvailable={1} bytesLeft={2}",
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bytesRead, bytesAvailable, bytesLeft),
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new Win32Exception());
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}
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// Sanity check: throw away message if it is > 1 MB
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if (ms.Length + bytesLeft > 1024 * 1024)
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{
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throw new Exception("Indecently large message sent into named pipe: rejecting.");
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}
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// Now allocate a buffer of the correct size and read in the message.
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byte[] readBuf = new byte[bytesAvailable];
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if (!ReadFile(Handle, readBuf, (uint)readBuf.Length, out bytesRead, ref overlapped))
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{
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Win32Exception exn = new Win32Exception();
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if (exn.NativeErrorCode == ERROR_MORE_DATA)
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{
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// The peek may have looked into the pipe before the write operation
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// had completed, and so reported a message size before the whole
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// message was sent. In this case we need to go round the loop again
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// with a larger buffer.
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ms.Write(readBuf, 0, (int)bytesRead);
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continue;
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}
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throw new Win32Exception($"ReadFile failed. readBuf.Length={readBuf.Length} bytesRead={bytesRead}", exn);
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}
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ms.Write(readBuf, 0, (int)bytesRead);
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break;
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}
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readMessage = ms.ToArray();
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}
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// Now perform a zero-byte write. This causes the CallNamedPipe call to
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// return successfully in the splash screen.
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byte[] toWrite = Array.Empty<byte>();
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if (!WriteFile(Handle, toWrite, (uint)toWrite.Length, out var bytesWritten, ref overlapped))
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{
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throw new Win32Exception($"WriteFile failed. toWrite.Length={toWrite.Length} bytesWritten={bytesWritten}", new Win32Exception());
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}
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var message = Encoding.Unicode.GetString(readMessage);
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if (message == STOP_LISTENING_MSG)
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{
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log.Debug("NamedPipe thread was told to stop listening");
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run = false;
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return;
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}
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// Now inform any listeners of the received data.
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Read?.Invoke(message);
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}
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}
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}
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}
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