From f4b2406d6aaced06edbeed9449bbb194add7b177 Mon Sep 17 00:00:00 2001 From: AlexOne Date: Fri, 14 May 2021 11:19:27 +0800 Subject: [PATCH] fix: DGuiApplicationHelper::setSingleInstance start multiple instances MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 用脚本启动实例，会发生单实例的程序启动多个实例的情况。 Log: Bug: https://pms.uniontech.com/zentao/bug-view-69284.html Change-Id: I935bc04b8c6c49df994d774370a68bc72d9a0f42 (cherry picked from commit 88e0b51da793d3d8b9d48c8515ddf1bf71814860) --- src/kernel/dguiapplicationhelper.cpp | 247 +++++++++++++++++++++++++++ 1 file changed, 247 insertions(+) diff --git a/src/kernel/dguiapplicationhelper.cpp b/src/kernel/dguiapplicationhelper.cpp index a7a4224b..f771ffd7 100644 --- a/src/kernel/dguiapplicationhelper.cpp +++ b/src/kernel/dguiapplicationhelper.cpp @@ -22,6 +22,7 @@ #include "private/dguiapplicationhelper_p.h" #include "dplatformhandle.h" +#include #include #include #include @@ -31,6 +32,7 @@ #include #include #include +#include #include @@ -40,6 +42,244 @@ DGUI_BEGIN_NAMESPACE +#ifdef QT_DEBUG +Q_LOGGING_CATEGORY(dgAppHelper, "dtk.dguihelper") +#else +Q_LOGGING_CATEGORY(dgAppHelper, "dtk.dguihelper", QtInfoMsg) +#endif + +#ifdef Q_OS_LINUX +class DInstanceGuard { +public: + static bool guard(const QString &name); + static void enterCriticalSection(); + static void leaveCriticalSection(); + + class DCriticalHolder { + public: + DCriticalHolder() { + DInstanceGuard::enterCriticalSection(); + } + ~DCriticalHolder() { + DInstanceGuard::leaveCriticalSection(); + } + }; + +private: + static bool setInstanceName(const QString &name); + static void shmInit(); + static void destroy(); + static void errorExitIf(bool cond, QStringView reason); + + struct SharedVarables { + pid_t pid[2]; + pthread_mutex_t mutex[2]; + + struct { + pid_t criticalProcessPid; + pthread_mutex_t criticalSectionMtx; + } CriticalSection; + }; + + static DInstanceGuard * s_pSelf; + static QString s_name; + + static int s_shmId; + static key_t s_shmKey; + + static QVector s_procIdPath; + static SharedVarables * s_pShm; + static int s_nLock; + +private: + DInstanceGuard(); + ~DInstanceGuard() = default; + DInstanceGuard(const DInstanceGuard &) = delete; + DInstanceGuard &operator=(const DInstanceGuard &) = delete; + DInstanceGuard(DInstanceGuard &&) = delete; + DInstanceGuard &operator=(DInstanceGuard &&) = delete; +}; + +DInstanceGuard * DInstanceGuard::s_pSelf = nullptr; +QString DInstanceGuard::s_name; + +int DInstanceGuard::s_shmId = 0; +key_t DInstanceGuard::s_shmKey = 0; + +QVector DInstanceGuard::s_procIdPath; +DInstanceGuard::SharedVarables * DInstanceGuard::s_pShm = nullptr; +int DInstanceGuard::s_nLock = -1; + +/*! + \internal DInstanceGuard::DInstanceGuard 构造 DInstanceGuard 实例并初始化 + + 需要预先传入 name 实例名，相同实例名的实例在系统中只能同时存在最好两个。锁是对两个 + pid 的保护，获取到锁才能改写 pid，最终是根据 pid 来判断当前有几个进程、应该启动几个 + 进程。传入的 name 应该按照 Session 或 Scope 做区分，比如同一个用户连接多个 + VNC、同一台主机登陆多个用户。 + */ +DInstanceGuard::DInstanceGuard() +{ + for (int i = 0; i < 2 && s_nLock == -1; ++i) { + if (pthread_mutex_trylock(&s_pShm->mutex[i]) != 0) { + continue; + } + s_nLock = i; + s_pShm->pid[i] = getpid(); + std::atexit(destroy); + } + QString criticalProc = QString("/proc/%1").arg(s_pShm->CriticalSection.criticalProcessPid); + if (s_pShm->CriticalSection.criticalProcessPid && !QFile(criticalProc).exists()) { + pthread_mutex_unlock(&s_pShm->CriticalSection.criticalSectionMtx); + } + + errorExitIf(s_nLock == -1, u"Has two instance running."); +} + +/*! + \internal DInstanceGuard::shmInit() 初始化共享内存 + + 对共享内存进行初始化，存放进程级别的互斥锁、记录进程的 pid。 +*/ +void DInstanceGuard::shmInit() +{ + s_shmKey = qHash(s_name); + s_procIdPath.resize(2); + + pthread_mutexattr_t mutexSharedAttr[2] = {}; + for (int i = 0; i < 2; ++i) { + pthread_mutexattr_setpshared(&mutexSharedAttr[i], PTHREAD_PROCESS_SHARED); + pthread_mutexattr_settype(&mutexSharedAttr[i], PTHREAD_MUTEX_RECURSIVE_NP); + } + + // 获取共享内存，如果不存在则创建并初始化 + bool clearFlag = false; + s_shmId = shmget(s_shmKey, 0, 0666 | IPC_CREAT); + if (s_shmId == -1) { + s_shmId = shmget(s_shmKey, sizeof(SharedVarables), 0666 | IPC_CREAT); + errorExitIf(s_shmId < 0, u"Create share memory failed."); + clearFlag = true; + } + s_pShm = static_cast(shmat(s_shmId, nullptr, 0)); + errorExitIf(!s_pShm, u"Attach share memory failed."); + if (clearFlag) memset(s_pShm, 0, sizeof(SharedVarables)); + + // 对已退出/新创建的进程的锁进行重新初始化，防止　mutex 内部错误 + for (int i = 0; i < 2; ++i) { + s_procIdPath[i] = QString("/proc/%1").arg(s_pShm->pid[i]); + if (s_pShm->pid[i] && !QFile(s_procIdPath[i]).exists()) { + pthread_mutex_destroy(&s_pShm->mutex[i]); + pthread_mutex_init(&s_pShm->mutex[i], &mutexSharedAttr[i]); + s_pShm->pid[i] = 0; + } + pthread_mutexattr_destroy(&mutexSharedAttr[i]); + } + + // 对临界区锁的有效性进行检测，重新初始化 + QString criticalProcPath = QString("/proc/%1").arg(s_pShm->CriticalSection.criticalProcessPid); + if (!s_pShm->CriticalSection.criticalProcessPid || !QFile(criticalProcPath).exists()) { + // Critical section init + pthread_mutexattr_t criticalMtxSharedAttr = {}; + pthread_mutexattr_setpshared(&criticalMtxSharedAttr, PTHREAD_PROCESS_SHARED); + pthread_mutexattr_settype(&criticalMtxSharedAttr, PTHREAD_MUTEX_RECURSIVE_NP); + pthread_mutex_init(&s_pShm->CriticalSection.criticalSectionMtx, &criticalMtxSharedAttr); + pthread_mutexattr_destroy(&criticalMtxSharedAttr); + } +} + +/*! + \fn DInstanceGuard::setInstanceName(const QString &name) 设置实例名 + + 根据实例名初始化对应的共享内存 +*/ +bool DInstanceGuard::setInstanceName(const QString &name) +{ + errorExitIf(name.isEmpty(), u"Set instance name error..."); + if (!s_name.isEmpty()) { + qCWarning(dgAppHelper, "Set instance name failed. already has a name..."); + return false; + } + s_name = name; + + return true; +} + +/*! + \fn DInstanceGuard::guard 创建 DInstanceGuard 实例 + + 传入 name 实例名，确保和当前 name 相同的实例在系统中只能同时存在不超过两个，确保后续可以完成后者到 + 前者的通信过程，最终只保留一个实例。负责完成 DGuiApplicationHelper::setSingleInstance 中的 + 第一阶段。 + */ +bool DInstanceGuard::guard(const QString &name) +{ + static std::once_flag initFlag; + bool retValue = false; + std::call_once(initFlag, [name, &retValue] { + retValue = setInstanceName(name); + shmInit(); + s_pSelf = s_pSelf ? s_pSelf : new DInstanceGuard(); + }); + + return retValue; +} + +/*! + \internal DInstanceGuard::destroy() 销毁共享内存 + + 只有在程序正常退出的时候由 atexit 的注册来调用。即使异常退出也不会对下次执行造成影响。 + */ +void DInstanceGuard::destroy() +{ + if (!s_pSelf) { + return; + } + + bool shmRelease = false; + int anotherProc = !s_nLock; + if (!QFile(s_procIdPath[anotherProc]).exists()) { + shmRelease = true; + pthread_mutex_unlock(&s_pShm->mutex[anotherProc]); + } + pthread_mutex_unlock(&s_pShm->mutex[s_nLock]); + if (s_pShm->CriticalSection.criticalProcessPid == getpid()) { + s_pShm->CriticalSection.criticalProcessPid = 0; + pthread_mutex_unlock(&s_pShm->CriticalSection.criticalSectionMtx); + } + if (shmRelease) { + shmctl(s_shmId, IPC_RMID, nullptr); + } + + delete s_pSelf; + s_pSelf = nullptr; +} + +/*! + \fn void DInstanceGuard::enterCriticalSection() + + 进入临界区。 按 Guard 传入的 name 进行代码段的保护。不能单独使用，必须先调用 Guard。 + 不能用于同一进程内的多线程。根据实例名的 scope，最大可提供系统级的保护。 + 确保 DGuiApplicationHelper::setSingleInstance 中的第二阶段正确执行。 +*/ +void DInstanceGuard::enterCriticalSection() { + errorExitIf(s_name.isEmpty() || !s_pSelf, u"Enter critical section failed. must set instance name first."); + if (pthread_mutex_lock(&s_pShm->CriticalSection.criticalSectionMtx) == 0) { + s_pShm->CriticalSection.criticalProcessPid = getpid(); + } +} + +void DInstanceGuard::leaveCriticalSection() { + pthread_mutex_unlock(&s_pShm->CriticalSection.criticalSectionMtx); +} + +void DInstanceGuard::errorExitIf(bool cond, QStringView reason) { + if (cond) { + qCWarning(dgAppHelper) << reason << " should exit program."; + qFatal("Error: DInstanceGuard::errorExitIf."); + } +} +#endif + Q_GLOBAL_STATIC(QLocalServer, _d_singleServer) static quint8 _d_singleServerVersion = 1; @@ -935,6 +1175,13 @@ bool DGuiApplicationHelper::setSingleInstance(const QString &key, DGuiApplicatio socket_key += key; +#ifdef Q_OS_LINUX + if (!DInstanceGuard::guard(socket_key)) { + return false; + } + DInstanceGuard::DCriticalHolder holder; +#endif + // 通知别的实例 QLocalSocket socket; socket.connectToServer(socket_key);