在C＃中使用Global Mutex有什么好的模式？

互斥类很容易被误解，而全局互斥更是如此。

创build全局互斥锁时使用什么好的安全模式？

一个会工作的

• 不pipe我的机器在哪个区域
• 保证正确释放互斥锁
• 如果互斥量未被获取，则可选地不永久挂起
• 处理其他进程放弃互斥体的情况

Answer 1

我想确定这是在那里，因为这是很难得到正确的：

using System.Runtime.InteropServices; //GuidAttribute using System.Reflection; //Assembly using System.Threading; //Mutex using System.Security.AccessControl; //MutexAccessRule using System.Security.Principal; //SecurityIdentifier static void Main(string[] args) { // get application GUID as defined in AssemblyInfo.cs string appGuid = ((GuidAttribute)Assembly.GetExecutingAssembly(). GetCustomAttributes(typeof(GuidAttribute), false). GetValue(0)).Value.ToString(); // unique id for global mutex - Global prefix means it is global to the machine string mutexId = string.Format( "Global\\{{{0}}}", appGuid ); // Need a place to store a return value in Mutex() constructor call bool createdNew; // edited by Jeremy Wiebe to add example of setting up security for multi-user usage // edited by 'Marc' to work also on localized systems (don't use just "Everyone") var allowEveryoneRule = new MutexAccessRule( new SecurityIdentifier( WellKnownSidType.WorldSid , null) , MutexRights.FullControl , AccessControlType.Allow ); var securitySettings = new MutexSecurity(); securitySettings.AddAccessRule(allowEveryoneRule); // edited by MasonGZhwiti to prevent race condition on security settings via VanNguyen using (var mutex = new Mutex(false, mutexId, out createdNew, securitySettings)) { // edited by acidzombie24 var hasHandle = false; try { try { // note, you may want to time out here instead of waiting forever // edited by acidzombie24 // mutex.WaitOne(Timeout.Infinite, false); hasHandle = mutex.WaitOne(5000, false); if (hasHandle == false) throw new TimeoutException("Timeout waiting for exclusive access"); } catch (AbandonedMutexException) { // Log the fact that the mutex was abandoned in another process, // it will still get acquired hasHandle = true; } // Perform your work here. } finally { // edited by acidzombie24, added if statement if(hasHandle) mutex.ReleaseMutex(); } } } 

Answer 2

使用接受的答案，我创build了一个帮助器类，以便您可以像使用Lock语句一样使用它。 只是想我会分享。

使用：

 using (new SingleGlobalInstance(1000)) //1000ms timeout on global lock { //Only 1 of these runs at a time RunSomeStuff(); } 

和助手类：

 class SingleGlobalInstance : IDisposable { //edit by user "jitbit" - renamed private fields to "_" public bool _hasHandle = false; Mutex _mutex; private void InitMutex() { string appGuid = ((GuidAttribute)Assembly.GetExecutingAssembly().GetCustomAttributes(typeof(GuidAttribute), false).GetValue(0)).Value.ToString(); string mutexId = string.Format("Global\\{{{0}}}", appGuid); _mutex = new Mutex(false, mutexId); var allowEveryoneRule = new MutexAccessRule(new SecurityIdentifier(WellKnownSidType.WorldSid, null), MutexRights.FullControl, AccessControlType.Allow); var securitySettings = new MutexSecurity(); securitySettings.AddAccessRule(allowEveryoneRule); _mutex.SetAccessControl(securitySettings); } public SingleGlobalInstance(int timeOut) { InitMutex(); try { if(timeOut < 0) _hasHandle = _mutex.WaitOne(Timeout.Infinite, false); else _hasHandle = _mutex.WaitOne(timeOut, false); if (_hasHandle == false) throw new TimeoutException("Timeout waiting for exclusive access on SingleInstance"); } catch (AbandonedMutexException) { _hasHandle = true; } } public void Dispose() { if (_mutex != null) { if (_hasHandle) _mutex.ReleaseMutex(); _mutex.Close(); } } } 

Answer 3

互斥体和WinApi CreateMutex（）都不适用于我。

另一种解决scheme：

 static class Program { [STAThread] static void Main() { if (SingleApplicationDetector.IsRunning()) { return; } Application.Run(new MainForm()); SingleApplicationDetector.Close(); } } 

和SingleApplicationDetector ：

 using System; using System.Reflection; using System.Runtime.InteropServices; using System.Security.AccessControl; using System.Threading; public static class SingleApplicationDetector { public static bool IsRunning() { string guid = ((GuidAttribute)Assembly.GetExecutingAssembly().GetCustomAttributes(typeof(GuidAttribute), false).GetValue(0)).Value.ToString(); var semaphoreName = @"Global\" + guid; try { __semaphore = Semaphore.OpenExisting(semaphoreName, SemaphoreRights.Synchronize); Close(); return true; } catch (Exception ex) { __semaphore = new Semaphore(0, 1, semaphoreName); return false; } } public static void Close() { if (__semaphore != null) { __semaphore.Close(); __semaphore = null; } } private static Semaphore __semaphore; } 

使用Semaphore而不是Mutex的原因：

互斥体类强制线程标识，所以互斥体只能由获取它的线程释放。 相比之下，Semaphore类不强制执行线程标识。

<< System.Threading.Mutex

参考： Semaphore.OpenExisting（）

Answer 4

在两个不同的用户同时运行的两个进程试图同时初始化互斥量的时候，在接受的答案中有一个竞争条件。 在第一个进程初始化互斥量之后，如果第二个进程在第一个进程将访问规则设置给所有人之前尝试初始化互斥量，则第二个进程将抛出未经授权的exception。

请参阅下面的更正答案：

 using System.Runtime.InteropServices; //GuidAttribute using System.Reflection; //Assembly using System.Threading; //Mutex using System.Security.AccessControl; //MutexAccessRule using System.Security.Principal; //SecurityIdentifier static void Main(string[] args) { // get application GUID as defined in AssemblyInfo.cs string appGuid = ((GuidAttribute)Assembly.GetExecutingAssembly().GetCustomAttributes(typeof(GuidAttribute), false).GetValue(0)).Value.ToString(); // unique id for global mutex - Global prefix means it is global to the machine string mutexId = string.Format( "Global\\{{{0}}}", appGuid ); bool createdNew; // edited by Jeremy Wiebe to add example of setting up security for multi-user usage // edited by 'Marc' to work also on localized systems (don't use just "Everyone") var allowEveryoneRule = new MutexAccessRule(new SecurityIdentifier(WellKnownSidType.WorldSid, null), MutexRights.FullControl, AccessControlType.Allow); var securitySettings = new MutexSecurity(); securitySettings.AddAccessRule(allowEveryoneRule); using (var mutex = new Mutex(false, mutexId, out createdNew, securitySettings)) { // edited by acidzombie24 var hasHandle = false; try { try { // note, you may want to time out here instead of waiting forever // edited by acidzombie24 // mutex.WaitOne(Timeout.Infinite, false); hasHandle = mutex.WaitOne(5000, false); if (hasHandle == false) throw new TimeoutException("Timeout waiting for exclusive access"); } catch (AbandonedMutexException) { // Log the fact the mutex was abandoned in another process, it will still get aquired hasHandle = true; } // Perform your work here. } finally { // edited by acidzombie24, added if statemnet if(hasHandle) mutex.ReleaseMutex(); } } } 

Answer 5

如果另一个实例已经在运行，此示例将在5秒后退出。

 // unique id for global mutex - Global prefix means it is global to the machine const string mutex_id = "Global\\{B1E7934A-F688-417f-8FCB-65C3985E9E27}"; static void Main(string[] args) { using (var mutex = new Mutex(false, mutex_id)) { try { try { if (!mutex.WaitOne(TimeSpan.FromSeconds(5), false)) { Console.WriteLine("Another instance of this program is running"); Environment.Exit(0); } } catch (AbandonedMutexException) { // Log the fact the mutex was abandoned in another process, it will still get aquired } // Perform your work here. } finally { mutex.ReleaseMutex(); } } }