Procedimiento para usar canalizaciones con nombre para la comunicación de red entre procesos

Artículo
01/02/2024

Las canalizaciones con nombre permiten la comunicación entre procesos entre un servidor de canalización y uno o varios clientes de canalización. Proporcionan más funcionalidad que las canalizaciones anónimas, que permiten la comunicación entre procesos en un equipo local. Las canalizaciones con nombre admiten la comunicación dúplex completa a través de una red y varias instancias de servidor, la comunicación mediante mensajes y la suplantación de clientes, que permite a los procesos que se conectan utilizar su propio conjunto de permisos en servidores remotos.

Importante

.NET en Linux usa sockets de dominio de Unix (UDS) para la implementación de estas API.

Para implementar canalizaciones con nombre, use las clases NamedPipeServerStream y NamedPipeClientStream.

Ejemplo 1

En el siguiente ejemplo se muestra cómo crear una canalización con nombre mediante la clase NamedPipeServerStream. En este ejemplo, el proceso de servidor crea cuatro subprocesos. Cada subproceso puede aceptar una conexión de cliente. A continuación, el proceso de cliente conectado proporciona un nombre de archivo al servidor. Si el cliente tiene los permisos necesarios, el proceso de servidor abre el archivo y envía su contenido de vuelta al cliente.

#using <System.Core.dll>

using namespace System;
using namespace System::IO;
using namespace System::IO::Pipes;
using namespace System::Text;
using namespace System::Threading;

// Defines the data protocol for reading and writing strings on our stream
public ref class StreamString
{
private:
    Stream^ ioStream;
    UnicodeEncoding^ streamEncoding;

public:
    StreamString(Stream^ ioStream)
    {
        this->ioStream = ioStream;
        streamEncoding = gcnew UnicodeEncoding();
    }

    String^ ReadString()
    {
        int len;

        len = ioStream->ReadByte() * 256;
        len += ioStream->ReadByte();
        array<Byte>^ inBuffer = gcnew array<Byte>(len);
        ioStream->Read(inBuffer, 0, len);

        return streamEncoding->GetString(inBuffer);
    }

    int WriteString(String^ outString)
    {
        array<Byte>^ outBuffer = streamEncoding->GetBytes(outString);
        int len = outBuffer->Length;
        if (len > UInt16::MaxValue)
        {
            len = (int)UInt16::MaxValue;
        }
        ioStream->WriteByte((Byte)(len / 256));
        ioStream->WriteByte((Byte)(len & 255));
        ioStream->Write(outBuffer, 0, len);
        ioStream->Flush();

        return outBuffer->Length + 2;
    }
};

// Contains the method executed in the context of the impersonated user
public ref class ReadFileToStream
{
private:
    String^ fn;
    StreamString ^ss;

public:
    ReadFileToStream(StreamString^ str, String^ filename)
    {
        fn = filename;
        ss = str;
    }

    void Start()
    {
        String^ contents = File::ReadAllText(fn);
        ss->WriteString(contents);
    }
};

public ref class PipeServer
{
private:
    static int numThreads = 4;

public:
    static void Main()
    {
        int i;
        array<Thread^>^ servers = gcnew array<Thread^>(numThreads);

        Console::WriteLine("\n*** Named pipe server stream with impersonation example ***\n");
        Console::WriteLine("Waiting for client connect...\n");
        for (i = 0; i < numThreads; i++)
        {
            servers[i] = gcnew Thread(gcnew ThreadStart(&ServerThread));
            servers[i]->Start();
        }
        Thread::Sleep(250);
        while (i > 0)
        {
            for (int j = 0; j < numThreads; j++)
            {
                if (servers[j] != nullptr)
                {
                    if (servers[j]->Join(250))
                    {
                        Console::WriteLine("Server thread[{0}] finished.", servers[j]->ManagedThreadId);
                        servers[j] = nullptr;
                        i--;    // decrement the thread watch count
                    }
                }
            }
        }
        Console::WriteLine("\nServer threads exhausted, exiting.");
    }

private:
    static void ServerThread()
    {
        NamedPipeServerStream^ pipeServer =
            gcnew NamedPipeServerStream("testpipe", PipeDirection::InOut, numThreads);

        int threadId = Thread::CurrentThread->ManagedThreadId;

        // Wait for a client to connect
        pipeServer->WaitForConnection();

        Console::WriteLine("Client connected on thread[{0}].", threadId);
        try
        {
            // Read the request from the client. Once the client has
            // written to the pipe its security token will be available.

            StreamString^ ss = gcnew StreamString(pipeServer);

            // Verify our identity to the connected client using a
            // string that the client anticipates.

            ss->WriteString("I am the one true server!");
            String^ filename = ss->ReadString();

            // Read in the contents of the file while impersonating the client.
            ReadFileToStream^ fileReader = gcnew ReadFileToStream(ss, filename);

            // Display the name of the user we are impersonating.
            Console::WriteLine("Reading file: {0} on thread[{1}] as user: {2}.",
                filename, threadId, pipeServer->GetImpersonationUserName());
            pipeServer->RunAsClient(gcnew PipeStreamImpersonationWorker(fileReader, &ReadFileToStream::Start));
        }
        // Catch the IOException that is raised if the pipe is broken
        // or disconnected.
        catch (IOException^ e)
        {
            Console::WriteLine("ERROR: {0}", e->Message);
        }
        pipeServer->Close();
    }
};

int main()
{
    PipeServer::Main();
}

using System;
using System.IO;
using System.IO.Pipes;
using System.Text;
using System.Threading;

public class PipeServer
{
    private static int numThreads = 4;

    public static void Main()
    {
        int i;
        Thread?[] servers = new Thread[numThreads];

        Console.WriteLine("\n*** Named pipe server stream with impersonation example ***\n");
        Console.WriteLine("Waiting for client connect...\n");
        for (i = 0; i < numThreads; i++)
        {
            servers[i] = new Thread(ServerThread);
            servers[i]?.Start();
        }
        Thread.Sleep(250);
        while (i > 0)
        {
            for (int j = 0; j < numThreads; j++)
            {
                if (servers[j] != null)
                {
                    if (servers[j]!.Join(250))
                    {
                        Console.WriteLine("Server thread[{0}] finished.", servers[j]!.ManagedThreadId);
                        servers[j] = null;
                        i--;    // decrement the thread watch count
                    }
                }
            }
        }
        Console.WriteLine("\nServer threads exhausted, exiting.");
    }

    private static void ServerThread(object? data)
    {
        NamedPipeServerStream pipeServer =
            new NamedPipeServerStream("testpipe", PipeDirection.InOut, numThreads);

        int threadId = Thread.CurrentThread.ManagedThreadId;

        // Wait for a client to connect
        pipeServer.WaitForConnection();

        Console.WriteLine("Client connected on thread[{0}].", threadId);
        try
        {
            // Read the request from the client. Once the client has
            // written to the pipe its security token will be available.

            StreamString ss = new StreamString(pipeServer);

            // Verify our identity to the connected client using a
            // string that the client anticipates.

            ss.WriteString("I am the one true server!");
            string filename = ss.ReadString();

            // Read in the contents of the file while impersonating the client.
            ReadFileToStream fileReader = new ReadFileToStream(ss, filename);

            // Display the name of the user we are impersonating.
            Console.WriteLine("Reading file: {0} on thread[{1}] as user: {2}.",
                filename, threadId, pipeServer.GetImpersonationUserName());
            pipeServer.RunAsClient(fileReader.Start);
        }
        // Catch the IOException that is raised if the pipe is broken
        // or disconnected.
        catch (IOException e)
        {
            Console.WriteLine("ERROR: {0}", e.Message);
        }
        pipeServer.Close();
    }
}

// Defines the data protocol for reading and writing strings on our stream
public class StreamString
{
    private Stream ioStream;
    private UnicodeEncoding streamEncoding;

    public StreamString(Stream ioStream)
    {
        this.ioStream = ioStream;
        streamEncoding = new UnicodeEncoding();
    }

    public string ReadString()
    {
        int len = 0;

        len = ioStream.ReadByte() * 256;
        len += ioStream.ReadByte();
        byte[] inBuffer = new byte[len];
        ioStream.Read(inBuffer, 0, len);

        return streamEncoding.GetString(inBuffer);
    }

    public int WriteString(string outString)
    {
        byte[] outBuffer = streamEncoding.GetBytes(outString);
        int len = outBuffer.Length;
        if (len > UInt16.MaxValue)
        {
            len = (int)UInt16.MaxValue;
        }
        ioStream.WriteByte((byte)(len / 256));
        ioStream.WriteByte((byte)(len & 255));
        ioStream.Write(outBuffer, 0, len);
        ioStream.Flush();

        return outBuffer.Length + 2;
    }
}

// Contains the method executed in the context of the impersonated user
public class ReadFileToStream
{
    private string fn;
    private StreamString ss;

    public ReadFileToStream(StreamString str, string filename)
    {
        fn = filename;
        ss = str;
    }

    public void Start()
    {
        string contents = File.ReadAllText(fn);
        ss.WriteString(contents);
    }
}

Imports System.IO
Imports System.IO.Pipes
Imports System.Text
Imports System.Threading

Public Class PipeServer
    Private Shared numThreads As Integer = 4

    Public Shared Sub Main()
        Dim i As Integer
        Dim servers(numThreads) As Thread

        Console.WriteLine(vbCrLf + "*** Named pipe server stream with impersonation example ***" + vbCrLf)
        Console.WriteLine("Waiting for client connect..." + vbCrLf)
        For i = 0 To numThreads - 1
            servers(i) = New Thread(AddressOf ServerThread)
            servers(i).Start()
        Next i
        Thread.Sleep(250)
        While i > 0
            For j As Integer = 0 To numThreads - 1
                If Not (servers(j) Is Nothing) Then
                    If servers(j).Join(250) Then
                        Console.WriteLine("Server thread[{0}] finished.", servers(j).ManagedThreadId)
                        servers(j) = Nothing
                        i -= 1    ' decrement the thread watch count
                    End If
                End If
            Next j
        End While
        Console.WriteLine(vbCrLf + "Server threads exhausted, exiting.")
    End Sub

    Private Shared Sub ServerThread(data As Object)
        Dim pipeServer As New _
            NamedPipeServerStream("testpipe", PipeDirection.InOut, numThreads)

        Dim threadId As Integer = Thread.CurrentThread.ManagedThreadId

        ' Wait for a client to connect
        pipeServer.WaitForConnection()

        Console.WriteLine("Client connected on thread[{0}].", threadId)
        Try
            ' Read the request from the client. Once the client has
            ' written to the pipe its security token will be available.

            Dim ss As new StreamString(pipeServer)

            ' Verify our identity to the connected client using a
            ' string that the client anticipates.

            ss.WriteString("I am the one true server!")
            Dim filename As String = ss.ReadString()

            ' Read in the contents of the file while impersonating the client.
            Dim fileReader As New ReadFileToStream(ss, filename)

            ' Display the name of the user we are impersonating.
            Console.WriteLine("Reading file: {0} on thread[{1}] as user: {2}.",
                filename, threadId, pipeServer.GetImpersonationUserName())
            pipeServer.RunAsClient(AddressOf fileReader.Start)
            ' Catch the IOException that is raised if the pipe is broken
            ' or disconnected.
        Catch e As IOException
            Console.WriteLine("ERROR: {0}", e.Message)
        End Try
        pipeServer.Close()
    End Sub
End Class

' Defines the data protocol for reading and writing strings on our stream
Public Class StreamString
    Private ioStream As Stream
    Private streamEncoding As UnicodeEncoding

    Public Sub New(ioStream As Stream)
        Me.ioStream = ioStream
        streamEncoding = New UnicodeEncoding(False, False)
    End Sub

    Public Function ReadString() As String
        Dim len As Integer = 0
        len = CType(ioStream.ReadByte(), Integer) * 256
        len += CType(ioStream.ReadByte(), Integer)
        Dim inBuffer As Array = Array.CreateInstance(GetType(Byte), len)
        ioStream.Read(inBuffer, 0, len)

        Return streamEncoding.GetString(CType(inBuffer, Byte()))
    End Function

    Public Function WriteString(outString As String) As Integer
        Dim outBuffer() As Byte = streamEncoding.GetBytes(outString)
        Dim len As Integer = outBuffer.Length
        If len > UInt16.MaxValue Then
            len = CType(UInt16.MaxValue, Integer)
        End If
        ioStream.WriteByte(CType(len \ 256, Byte))
        ioStream.WriteByte(CType(len And 255, Byte))
        ioStream.Write(outBuffer, 0, outBuffer.Length)
        ioStream.Flush()

        Return outBuffer.Length + 2
    End Function
End Class

' Contains the method executed in the context of the impersonated user
Public Class ReadFileToStream
    Private fn As String
    Private ss As StreamString

    Public Sub New(str As StreamString, filename As String)
        fn = filename
        ss = str
    End Sub

    Public Sub Start()
        Dim contents As String = File.ReadAllText(fn)
        ss.WriteString(contents)
    End Sub
End Class

Ejemplo 2

En el ejemplo siguiente se muestra el proceso de cliente, que utiliza la clase NamedPipeClientStream. El cliente se conecta al proceso de servidor y envía un nombre de archivo al servidor. En el ejemplo, se utiliza la suplantación, por lo que la identidad que ejecuta la aplicación cliente debe tener permiso de acceso al archivo. A continuación, el servidor devuelve el contenido del archivo al cliente. El contenido del archivo se muestra en la consola.

using System;
using System.Diagnostics;
using System.IO;
using System.IO.Pipes;
using System.Security.Principal;
using System.Text;
using System.Threading;

public class PipeClient
{
    private static int numClients = 4;

    public static void Main(string[] args)
    {
        if (args.Length > 0)
        {
            if (args[0] == "spawnclient")
            {
                var pipeClient =
                    new NamedPipeClientStream(".", "testpipe",
                        PipeDirection.InOut, PipeOptions.None,
                        TokenImpersonationLevel.Impersonation);

                Console.WriteLine("Connecting to server...\n");
                pipeClient.Connect();

                var ss = new StreamString(pipeClient);
                // Validate the server's signature string.
                if (ss.ReadString() == "I am the one true server!")
                {
                    // The client security token is sent with the first write.
                    // Send the name of the file whose contents are returned
                    // by the server.
                    ss.WriteString("c:\\textfile.txt");

                    // Print the file to the screen.
                    Console.Write(ss.ReadString());
                }
                else
                {
                    Console.WriteLine("Server could not be verified.");
                }
                pipeClient.Close();
                // Give the client process some time to display results before exiting.
                Thread.Sleep(4000);
            }
        }
        else
        {
            Console.WriteLine("\n*** Named pipe client stream with impersonation example ***\n");
            StartClients();
        }
    }

    // Helper function to create pipe client processes
    private static void StartClients()
    {
        string currentProcessName = Environment.CommandLine;

        // Remove extra characters when launched from Visual Studio
        currentProcessName = currentProcessName.Trim('"', ' ');

        currentProcessName = Path.ChangeExtension(currentProcessName, ".exe");
        Process?[] plist = new Process?[numClients];

        Console.WriteLine("Spawning client processes...\n");

        if (currentProcessName.Contains(Environment.CurrentDirectory))
        {
            currentProcessName = currentProcessName.Replace(Environment.CurrentDirectory, String.Empty);
        }

        // Remove extra characters when launched from Visual Studio
        currentProcessName = currentProcessName.Replace("\\", String.Empty);
        currentProcessName = currentProcessName.Replace("\"", String.Empty);

        int i;
        for (i = 0; i < numClients; i++)
        {
            // Start 'this' program but spawn a named pipe client.
            plist[i] = Process.Start(currentProcessName, "spawnclient");
        }
        while (i > 0)
        {
            for (int j = 0; j < numClients; j++)
            {
                if (plist[j] != null)
                {
                    if (plist[j]!.HasExited)
                    {
                        Console.WriteLine($"Client process[{plist[j]?.Id}] has exited.");
                        plist[j] = null;
                        i--;    // decrement the process watch count
                    }
                    else
                    {
                        Thread.Sleep(250);
                    }
                }
            }
        }
        Console.WriteLine("\nClient processes finished, exiting.");
    }
}

// Defines the data protocol for reading and writing strings on our stream.
public class StreamString
{
    private Stream ioStream;
    private UnicodeEncoding streamEncoding;

    public StreamString(Stream ioStream)
    {
        this.ioStream = ioStream;
        streamEncoding = new UnicodeEncoding();
    }

    public string ReadString()
    {
        int len;
        len = ioStream.ReadByte() * 256;
        len += ioStream.ReadByte();
        var inBuffer = new byte[len];
        ioStream.Read(inBuffer, 0, len);

        return streamEncoding.GetString(inBuffer);
    }

    public int WriteString(string outString)
    {
        byte[] outBuffer = streamEncoding.GetBytes(outString);
        int len = outBuffer.Length;
        if (len > UInt16.MaxValue)
        {
            len = (int)UInt16.MaxValue;
        }
        ioStream.WriteByte((byte)(len / 256));
        ioStream.WriteByte((byte)(len & 255));
        ioStream.Write(outBuffer, 0, len);
        ioStream.Flush();

        return outBuffer.Length + 2;
    }
}

Imports System.Diagnostics
Imports System.IO
Imports System.IO.Pipes
Imports System.Security.Principal
Imports System.Text
Imports System.Threading

Public Class PipeClient
    Private Shared numClients As Integer = 4

    Public Shared Sub Main(args() As String)
        If args.Length > 0 Then
            If args(0) = "spawnclient" Then
                Dim pipeClient As New NamedPipeClientStream( _
                    ".", "testpipe", _
                    PipeDirection.InOut, PipeOptions.None, _
                    TokenImpersonationLevel.Impersonation)

                Console.WriteLine("Connecting to server..." + vbCrLf)
                pipeClient.Connect()

                Dim ss As New StreamString(pipeClient)
                ' Validate the server's signature string.
                If ss.ReadString() = "I am the one true server!" Then
                    ' The client security token is sent with the first write.
                    ' Send the name of the file whose contents are returned
                    ' by the server.
                    ss.WriteString("c:\textfile.txt")

                    ' Print the file to the screen.
                    Console.Write(ss.ReadString())
                Else
                    Console.WriteLine("Server could not be verified.")
                End If
                pipeClient.Close()
                ' Give the client process some time to display results before exiting.
                Thread.Sleep(4000)
            End If
        Else
            Console.WriteLine(vbCrLf + "*** Named pipe client stream with impersonation example ***" + vbCrLf)
            StartClients()
        End If
    End Sub

    ' Helper function to create pipe client processes
    Private Shared Sub StartClients()
        Dim currentProcessName As String = Environment.CommandLine
        Dim plist(numClients - 1) As Process

        Console.WriteLine("Spawning client processes..." + vbCrLf)

        If currentProcessName.Contains(Environment.CurrentDirectory) Then
            currentProcessName = currentProcessName.Replace(Environment.CurrentDirectory, String.Empty)
        End If

        ' Remove extra characters when launched from Visual Studio.
        currentProcessName = currentProcessName.Replace("\", String.Empty)
        currentProcessName = currentProcessName.Replace("""", String.Empty)

        ' Change extension for .NET Core "dotnet run" returns the DLL, not the host exe.
        currentProcessName = Path.ChangeExtension(currentProcessName, ".exe")

        Dim i As Integer
        For i = 0 To numClients - 1
            ' Start 'this' program but spawn a named pipe client.
            plist(i) = Process.Start(currentProcessName, "spawnclient")
        Next
        While i > 0
            For j As Integer = 0 To numClients - 1
                If plist(j) IsNot Nothing Then
                    If plist(j).HasExited Then
                        Console.WriteLine($"Client process[{plist(j).Id}] has exited.")
                        plist(j) = Nothing
                        i -= 1    ' decrement the process watch count
                    Else
                        Thread.Sleep(250)
                    End If
                End If
            Next
        End While
        Console.WriteLine(vbCrLf + "Client processes finished, exiting.")
    End Sub
End Class

' Defines the data protocol for reading and writing strings on our stream
Public Class StreamString
    Private ioStream As Stream
    Private streamEncoding As UnicodeEncoding

    Public Sub New(ioStream As Stream)
        Me.ioStream = ioStream
        streamEncoding = New UnicodeEncoding(False, False)
    End Sub

    Public Function ReadString() As String
        Dim len As Integer = 0
        len = CType(ioStream.ReadByte(), Integer) * 256
        len += CType(ioStream.ReadByte(), Integer)
        Dim inBuffer As Array = Array.CreateInstance(GetType(Byte), len)
        ioStream.Read(inBuffer, 0, len)

        Return streamEncoding.GetString(CType(inBuffer, Byte()))
    End Function

    Public Function WriteString(outString As String) As Integer
        Dim outBuffer As Byte() = streamEncoding.GetBytes(outString)
        Dim len As Integer = outBuffer.Length
        If len > UInt16.MaxValue Then
            len = CType(UInt16.MaxValue, Integer)
        End If
        ioStream.WriteByte(CType(len \ 256, Byte))
        ioStream.WriteByte(CType(len And 255, Byte))
        ioStream.Write(outBuffer, 0, outBuffer.Length)
        ioStream.Flush()

        Return outBuffer.Length + 2
    End Function
End Class

Programación sólida

Los procesos de servidor y cliente de este ejemplo están diseñados para ejecutarse en el mismo equipo, por lo que el nombre del servidor proporcionado al objeto NamedPipeClientStream es ".". Si los procesos de servidor y cliente estuvieran en equipos independientes, "." se reemplazaría por el nombre de red del equipo que ejecuta el proceso de servidor.

Vea también

TokenImpersonationLevel
GetImpersonationUserName
Pipes (Operaciones de canalización de .NET Framework)
Cómo: Usar canalizaciones anónimas para la comunicación local entre procesos

Compartir a través de

Procedimiento para usar canalizaciones con nombre para la comunicación de red entre procesos

Ejemplo 1

Ejemplo 2

Programación sólida

Vea también

Recursos adicionales