xenadmin/XenCenterLib/NamedPipes.cs
Konstantina Chremmou abf4ae3f35 CP-36392 pt.1: Removed unused using directives.
Signed-off-by: Konstantina Chremmou <konstantina.chremmou@citrix.com>
2021-04-07 10:04:47 +01:00

445 lines
19 KiB
C#

/* Copyright (c) Citrix Systems, Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms,
* with or without modification, are permitted provided
* that the following conditions are met:
*
* * Redistributions of source code must retain the above
* copyright notice, this list of conditions and the
* following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the
* following disclaimer in the documentation and/or other
* materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
* CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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*/
using System;
using System.ComponentModel;
using System.IO;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading;
namespace XenCenterLib
{
public class NamedPipes
{
[Flags]
public enum FileAccess : uint
{
GenericRead = 0x80000000,
GenericWrite = 0x40000000,
GenericExecute = 0x20000000,
GenericAll = 0x10000000
}
[Flags]
public enum FileShare : uint
{
None = 0x00000000,
/// <summary>
/// Enables subsequent open operations on an object to request read access.
/// Otherwise, other processes cannot open the object if they request read access.
/// If this flag is not specified, but the object has been opened for read access, the function fails.
/// </summary>
Read = 0x00000001,
/// <summary>
/// Enables subsequent open operations on an object to request write access.
/// Otherwise, other processes cannot open the object if they request write access.
/// If this flag is not specified, but the object has been opened for write access, the function fails.
/// </summary>
Write = 0x00000002,
/// <summary>
/// Enables subsequent open operations on an object to request delete access.
/// Otherwise, other processes cannot open the object if they request delete access.
/// If this flag is not specified, but the object has been opened for delete access, the function fails.
/// </summary>
Delete = 0x00000004
}
public enum FileMode : uint
{
/// <summary>
/// Creates a new file. The function fails if a specified file exists.
/// </summary>
CreateNew = 1,
/// <summary>
/// Creates a new file, always.
/// If a file exists, the function overwrites the file, clears the existing attributes, combines the specified file attributes,
/// and flags with FILE_ATTRIBUTE_ARCHIVE, but does not set the security descriptor that the SECURITY_ATTRIBUTES structure specifies.
/// </summary>
CreateAlways = 2,
/// <summary>
/// Opens a file. The function fails if the file does not exist.
/// </summary>
OpenExisting = 3,
/// <summary>
/// Opens a file, always.
/// If a file does not exist, the function creates a file as if dwCreationDisposition is CREATE_NEW.
/// </summary>
OpenAlways = 4,
/// <summary>
/// Opens a file and truncates it so that its size is 0 (zero) bytes. The function fails if the file does not exist.
/// The calling process must open the file with the GENERIC_WRITE access right.
/// </summary>
TruncateExisting = 5
}
[Flags]
public enum FileAttributes : uint
{
Readonly = 0x00000001,
Hidden = 0x00000002,
System = 0x00000004,
Directory = 0x00000010,
Archive = 0x00000020,
Device = 0x00000040,
Normal = 0x00000080,
Temporary = 0x00000100,
SparseFile = 0x00000200,
ReparsePoint = 0x00000400,
Compressed = 0x00000800,
Offline = 0x00001000,
NotContentIndexed = 0x00002000,
Encrypted = 0x00004000,
Write_Through = 0x80000000,
Overlapped = 0x40000000,
NoBuffering = 0x20000000,
RandomAccess = 0x10000000,
SequentialScan = 0x08000000,
DeleteOnClose = 0x04000000,
BackupSemantics = 0x02000000,
PosixSemantics = 0x01000000,
OpenReparsePoint = 0x00200000,
OpenNoRecall = 0x00100000,
FirstPipeInstance = 0x00080000
}
/// <summary>
/// Duplex pipe access.
/// </summary>
private const uint PIPE_ACCESS_DUPLEX = 0x00000003;
/// <summary>
/// Pipe blocking mode.
/// </summary>
private const uint PIPE_WAIT = 0x00000000;
/// <summary>
/// Pipe read mode of type Message.
/// </summary>
private const uint PIPE_READMODE_MESSAGE = 0x00000002;
/// <summary>
/// Message pipe type.
/// </summary>
private const uint PIPE_TYPE_MESSAGE = 0x00000004;
/// <summary>
/// Unlimited server pipe instances.
/// </summary>
private const uint PIPE_UNLIMITED_INSTANCES = 255;
/// <summary>
/// Waits indefinitely when connecting to a pipe.
/// </summary>
private const uint NMPWAIT_WAIT_FOREVER = 0xffffffff;
/// <summary>
/// Invalid operating system handle.
/// </summary>
private const int INVALID_HANDLE_VALUE = -1;
/// <summary>
/// More data is available.
/// </summary>
private const int ERROR_MORE_DATA = 234;
/// <summary>
/// There is a process on other end of the pipe.
/// </summary>
private const int ERROR_PIPE_CONNECTED = 535;
[DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
private static extern IntPtr CreateNamedPipe(String pipeName, uint openMode, uint pipeMode,
uint maxInstances, uint outputBufferSize, uint inputBufferSize, uint timeoutInterval,
IntPtr pipeSecurityDescriptor);
/// <summary>
/// Enables a named pipe server process to wait for a client
/// process to connect to an instance of a named pipe.
/// </summary>
/// <param name="hHandle">Handle to the server end of a named pipe instance.</param>
/// <param name="lpOverlapped">Pointer to an
/// <see cref="AppModule.NamedPipes.Overlapped">Overlapped</see> object.</param>
/// <returns>If the function succeeds, the return value is nonzero.</returns>
[DllImport("kernel32.dll", SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
private static extern bool ConnectNamedPipe(IntPtr namedPipeHandle, ref NativeOverlapped overlapped);
/// <summary>
/// Disconnects the server end of a named pipe instance from a client process.
/// </summary>
/// <param name="hHandle">Handle to an instance of a named pipe.</param>
/// <returns>If the function succeeds, the return value is nonzero.</returns>
[DllImport("kernel32.dll", SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
private static extern bool DisconnectNamedPipe(IntPtr hHandle);
/// <summary>
/// Reads data from a file, starting at the position indicated by the file pointer.
/// </summary>
/// <param name="hHandle">Handle to the file to be read.</param>
/// <param name="lpBuffer">Pointer to the buffer that receives the data read from the file.</param>
/// <param name="nNumberOfBytesToRead">Number of bytes to be read from the file.</param>
/// <param name="lpNumberOfBytesRead">Pointer to the variable that receives the number of bytes read.</param>
/// <param name="lpOverlapped">Pointer to an
/// <see cref="AppModule.NamedPipes.Overlapped">Overlapped</see> object.</param>
/// <returns>The ReadFile function returns when one of the following
/// conditions is met: a write operation completes on the write end of
/// the pipe, the number of bytes requested has been read, or an error occurs.</returns>
[DllImport("kernel32.dll", SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
private static extern bool ReadFile(IntPtr fileHandle, [Out] byte[] dataBuffer, uint nNumberOfBytesToRead,
out uint lpNumberOfBytesRead, [In] ref NativeOverlapped overlapped);
[DllImport("kernel32.dll", SetLastError = true)]
private static extern bool WriteFile(IntPtr fileHandle, [Out] byte[] dataBuffer, uint nNumberOfBytesToWrite,
out uint lpNumberOfBytesWritten, [In] ref NativeOverlapped overlapped);
[DllImport("kernel32.dll", SetLastError = true)]
private static extern bool PeekNamedPipe(IntPtr handle, [Out] byte[] buffer, uint nBufferSize,
out uint bytesRead, out uint bytesAvail, out uint BytesLeftThisMessage);
[DllImport("kernel32.dll")]
private static extern bool CallNamedPipe(string lpNamedPipeName, byte[] lpInBuffer,
uint nInBufferSize, [Out] byte[] lpOutBuffer, uint nOutBufferSize,
out uint lpBytesRead, uint nTimeOut);
[DllImport("kernel32.dll", SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
private static extern bool CloseHandle(IntPtr hObject);
private const string STOP_LISTENING_MSG = "stop-listening-on-pipe";
public class Pipe
{
private static readonly log4net.ILog log = log4net.LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType);
public readonly IntPtr Handle;
public EventHandler<PipeReadEventArgs> Read;
private Thread pipeThread;
private readonly string pipePath;
private volatile bool run;
/// <exception cref="Win32Exception">If creating the pipe failed for any reason.</exception>
public Pipe(string path)
{
this.pipePath = path;
Handle = CreateNamedPipe(pipePath, PIPE_ACCESS_DUPLEX,
PIPE_TYPE_MESSAGE | PIPE_READMODE_MESSAGE | PIPE_WAIT,
PIPE_UNLIMITED_INSTANCES, 512, 512, NMPWAIT_WAIT_FOREVER, IntPtr.Zero);
if (Handle.ToInt32() == INVALID_HANDLE_VALUE)
{
// Throw last win32 exception
throw new Win32Exception();
}
}
/// <summary>
/// Starts reading from this pipe on a new background thread. This call returns immediately.
/// Whenever data is read from the pipe, the Read event is fired.
/// </summary>
public void BeginRead()
{
if (pipeThread == null)
{
run = true;
pipeThread = new Thread((ThreadStart)BackgroundPipeThread);
pipeThread.Name = "Named pipe thread";
pipeThread.IsBackground = true;
pipeThread.Start();
}
}
/// <summary>
/// May block for up to 30 seconds.
/// </summary>
public void Disconnect()
{
// Now connect to our own NamedPipe and sent a disconnect message
if (pipeThread != null)
{
byte[] msg = Encoding.UTF8.GetBytes(STOP_LISTENING_MSG);
byte[] rcv = new byte[0];
UInt32 bytesRead;
UInt32 timeout = 30 * 1000;
CallNamedPipe(pipePath, msg, (UInt32)msg.Length, rcv, (UInt32)rcv.Length, out bytesRead, timeout);
}
}
private void BackgroundPipeThread()
{
while (run)
{
try
{
NativeOverlapped overlapped = new NativeOverlapped();
if (!ConnectNamedPipe(Handle, ref overlapped))
{
Win32Exception exn = new Win32Exception();
if (exn.NativeErrorCode == ERROR_PIPE_CONNECTED)
{
// This is OK. It simply means a remote process has connected to the
// named pipe since we did the CreateNamedPipe.
}
else
{
throw new Win32Exception("ConnectNamedPipe failed", exn);
}
}
ProcessPipeMessage();
if (!DisconnectNamedPipe(Handle))
{
throw new Win32Exception("DisconnectNamedPipe failed", new Win32Exception());
}
}
catch (Exception exn)
{
log.Error("Error in named pipe thread.", exn);
// Sanity: pause after errors to prevent massive log spamming/CPU drain
// in the event of an infinite error loop
Thread.Sleep(1000);
}
}
// Close pipe handle to destroy it
if (CloseHandle(Handle))
log.Debug("Closed NamedPipe handle");
else
log.Warn("CloseHandle() in NamedPipes failed", new Win32Exception());
log.Debug("NamedPipe thread exited");
}
private void ProcessPipeMessage()
{
NativeOverlapped overlapped = new NativeOverlapped();
byte[] readMessage;
using (MemoryStream ms = new MemoryStream())
{
while (true)
{
// Loop as follows:
// Peek at the pipe to see how much data is available
// Read the data and append it to the buffer
// If we get ERROR_MORE_DATA, repeat
UInt32 bytesRead, bytesAvailable, bytesLeft;
// First peek into the pipe to see how much data is waiting.
byte[] peekBuf = new byte[0];
if (!PeekNamedPipe(Handle, peekBuf, (UInt32)peekBuf.Length, out bytesRead, out bytesAvailable, out bytesLeft))
{
throw new Win32Exception(
string.Format("PeekNamedPipe failed. bytesRead={0} bytesAvailable={1} bytesLeft={2}",
bytesRead, bytesAvailable, bytesLeft),
new Win32Exception());
}
// Sanity check: throw away message if it is > 1 MB
if (ms.Length + bytesLeft > 1024 * 1024)
{
throw new Exception("Indecently large message sent into named pipe: rejecting.");
}
// Now allocate a buffer of the correct size and read in the message.
byte[] readBuf = new byte[bytesAvailable];
if (!ReadFile(Handle, readBuf, (UInt32)readBuf.Length, out bytesRead, ref overlapped))
{
Win32Exception exn = new Win32Exception();
if (exn.NativeErrorCode == ERROR_MORE_DATA)
{
// The peek may have looked into the pipe before the write operation
// had completed, and so reported a message size before the whole
// message was sent. In this case we need to go round the loop again
// with a larger buffer.
ms.Write(readBuf, 0, (int)bytesRead);
continue;
}
else
{
throw new Win32Exception(
string.Format("ReadFile failed. readBuf.Length={0} bytesRead={1}",
readBuf.Length, bytesRead), exn);
}
}
else
{
ms.Write(readBuf, 0, (int)bytesRead);
break;
}
}
readMessage = ms.ToArray();
}
// Now perform a zero-byte write. This causes the CallNamedPipe call to
// return successfully in the splash screen.
UInt32 bytesWritten;
byte[] toWrite = new byte[0];
if (!WriteFile(Handle, toWrite, (UInt32)toWrite.Length, out bytesWritten, ref overlapped))
{
throw new Win32Exception(
string.Format("WriteFile failed. toWrite.Length={0} bytesWritten={1}",
toWrite.Length, bytesWritten),
new Win32Exception());
}
PipeReadEventArgs e = new PipeReadEventArgs(readMessage);
if (e.Message == STOP_LISTENING_MSG)
{
log.Debug("NamedPipe thread was told to stop listening");
run = false;
return;
}
// Now inform any listeners of the received data.
if (Read != null)
{
Read(null, e);
}
}
}
public class PipeReadEventArgs : EventArgs
{
public readonly string Message;
public PipeReadEventArgs(byte[] bytes)
{
Message = Encoding.Unicode.GetString(bytes);
}
}
}
}