135 lines
4.2 KiB
Plaintext
135 lines
4.2 KiB
Plaintext
// ----------------------------------------------------------------------------
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//
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// Copyright (c) Microsoft Corporation. All rights reserved.
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//
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// ----------------------------------------------------------------------------
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namespace Microsoft.Singularity.Security
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{
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using System;
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using System.Collections;
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using System.Threading;
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using Microsoft.SingSharp;
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using Microsoft.Contracts;
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using Microsoft.Singularity.Channels;
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using Microsoft.Singularity.Directory;
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/// <summary>
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/// A <code>ChannelPool</code> maintains a pool of open channels.
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/// (to the security service). It should be possible to parameterize this
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/// class for general use.
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/// </summary>
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internal class ChannelPool
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{
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#if POOLED
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const int POOL_CAPACITY = 10;
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#else
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const int POOL_CAPACITY = 1;
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#endif
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/// <summary>
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/// The unused channels
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/// </summary>
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TRef<SecurityDiagnosticsContract.Imp, SecurityDiagnosticsContract.ReadyState>[]! trefs;
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int capacity = POOL_CAPACITY;
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int nalloc = 0;
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int navail = 0;
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/// <summary>
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/// Synchronization token
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/// </summary>
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object token;
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bool disposed;
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public ChannelPool()
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{
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int i;
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trefs = new TRef<SecurityDiagnosticsContract.Imp, SecurityDiagnosticsContract.ReadyState>[capacity];
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token = new object();
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disposed = false;
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}
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// opens a connection to the security service
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private static SecurityDiagnosticsContract.Imp OpenChannel()
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{
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SecurityDiagnosticsContract.Imp! imp;
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SecurityDiagnosticsContract.Exp! exp;
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SecurityDiagnosticsContract.NewChannel(out imp, out exp);
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// open a channel to the nameservice
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DirectoryServiceContract.Imp ns = DirectoryService.NewClientEndpoint();
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// try to bind
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ns.SendBind(Bitter.FromString2(SecurityDiagnosticsContract.ModuleName), exp);
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switch receive {
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case ns.AckBind():
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break;
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case ns.NakBind(rejected, error):
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delete imp;
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delete rejected;
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delete ns;
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return null;
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}
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delete ns;
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imp.RecvReady();
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return imp;
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}
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/// <summary>
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/// Returns a free channel. Blocks if none is available.
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/// </summary>
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public SecurityDiagnosticsContract.Imp! Acquire()
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{
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lock (token) {
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// wait if no channel is available
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while (true) {
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if (navail != 0) {
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navail--;
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return ((!)trefs[navail]).Acquire();
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}
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if (nalloc < capacity) {
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SecurityDiagnosticsContract.Imp imp = OpenChannel();
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if (imp != null) {
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trefs[nalloc] = new
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TRef<SecurityDiagnosticsContract.Imp, SecurityDiagnosticsContract.ReadyState>
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(imp);
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return ((!)trefs[nalloc++]).Acquire();
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}
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}
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Monitor.Wait(token);
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}
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}
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}
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/// <summary>
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/// Releases a channel
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/// </summary>
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public void Release([Claims]SecurityDiagnosticsContract.Imp! imp)
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{
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lock (token) {
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((!)trefs[navail++]).Release(imp);
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Monitor.PulseAll(token);
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}
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}
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/// <summary>
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/// Closes the channels
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/// </summary>
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public void Dispose()
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{
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lock (token) {
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if (!disposed) {
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int i;
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for (i = 0; i < navail; i++) {
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SecurityDiagnosticsContract.Imp! imp = ((!)trefs[i]).Acquire();
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delete imp;
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}
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disposed = true;
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}
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}
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}
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}
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}
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