| Message ID | 20190818011329.14499-14-laurent.pinchart@ideasonboard.com |
|---|---|
| State | Accepted |
| Headers | show |
| Series |
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| Related | show |
On Sun, Aug 18, 2019 at 04:13:28AM +0300, Laurent Pinchart wrote: > The CameraManager class is not supposed to be instantiated multiple > times, which led to a singleton implementation. This requires a global > instance of the CameraManager, which is destroyed when the global > destructors are executed. > > Relying on global instances causes issues with cleanup, as the order in > which the global destructors are run can't be controlled. In particular, > the Android camera HAL implementation ends up destroying the > CameraHalManager after the CameraManager, which leads to use-after-free > problems. > > To solve this, remove the CameraManager::instance() method and make the > CameraManager class instantiable directly. Multiple instances are still > not allowed, and this is enforced by storing the instance pointer > internally to be checked when an instance is created. > > Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> > --- > include/libcamera/camera_manager.h | 12 ++++---- > src/android/camera_hal_manager.cpp | 5 +++- > src/cam/main.cpp | 8 ++++- > src/libcamera/camera_manager.cpp | 36 ++++++++++------------- > src/qcam/main.cpp | 4 ++- > test/camera/camera_test.cpp | 3 +- > test/controls/control_list.cpp | 3 +- > test/list-cameras.cpp | 11 +++---- > test/pipeline/ipu3/ipu3_pipeline_test.cpp | 3 +- > 9 files changed, 48 insertions(+), 37 deletions(-) > [snip] > > +CameraManager *CameraManager::self_ = nullptr; > + > CameraManager::CameraManager() > : enumerator_(nullptr) > { > + if (self_) > + LOG(Camera, Fatal) > + << "Multiple CameraManager objects are not allowed"; > + > + self_ = this; This is a very weak guarantee that the CameraManager would not be created twice... I was wondering, our previous singleton implementation was based on lazy evaluation, by returning a statically allocated CameraManager instance: CameraManager *CameraManager::instance() { static CameraManager manager; return &manager; } This mean it gets deleted at program termination time causing the issue you're here trying to solve. What if the make the manager creation dynamic instead and provide a static destructor method, that applications could call to guarantee the manager is deleted at the right time? Would something like this work in your opinion? diff --git a/include/libcamera/camera_manager.h b/include/libcamera/camera_manager.h index ff7d4c7c6745..a29a24f5e37a 100644 --- a/include/libcamera/camera_manager.h +++ b/include/libcamera/camera_manager.h @@ -33,6 +33,7 @@ public: void removeCamera(Camera *camera); static CameraManager *instance(); + static void destroy(); static const std::string &version() { return version_; } void setEventDispatcher(std::unique_ptr<EventDispatcher> dispatcher); @@ -49,6 +50,8 @@ private: std::vector<std::shared_ptr<Camera>> cameras_; static const std::string version_; + + static CameraManager *manager_; }; } /* namespace libcamera */ diff --git a/src/libcamera/camera_manager.cpp b/src/libcamera/camera_manager.cpp index 4a880684c5cb..ed175ccc5860 100644 --- a/src/libcamera/camera_manager.cpp +++ b/src/libcamera/camera_manager.cpp @@ -26,6 +26,8 @@ namespace libcamera { LOG_DEFINE_CATEGORY(Camera) +CameraManager *CameraManager::manager_ = nullptr; + /** * \class CameraManager * \brief Provide access and manage all cameras in the system @@ -223,8 +225,16 @@ void CameraManager::removeCamera(Camera *camera) */ CameraManager *CameraManager::instance() { - static CameraManager manager; - return &manager; + if (!manager_) + manager_ = new CameraManager(); + + return manager_; +} + +void CameraManager::destroy() +{ + delete manager_; + manager_ = nullptr; } /** Thanks j > } > > CameraManager::~CameraManager() > { > + self_ = nullptr; > } > > /** > @@ -212,21 +223,6 @@ void CameraManager::removeCamera(Camera *camera) > } > } > > -/** > - * \brief Retrieve the camera manager instance > - * > - * The CameraManager is a singleton and can't be constructed manually. This > - * function shall instead be used to retrieve the single global instance of the > - * manager. > - * > - * \return The camera manager instance > - */ > -CameraManager *CameraManager::instance() > -{ > - static CameraManager manager; > - return &manager; > -} > - > /** > * \fn const std::string &CameraManager::version() > * \brief Retrieve the libcamera version string > diff --git a/src/qcam/main.cpp b/src/qcam/main.cpp > index 05d3b77e9edb..a7ff5c52663b 100644 > --- a/src/qcam/main.cpp > +++ b/src/qcam/main.cpp > @@ -63,7 +63,7 @@ int main(int argc, char **argv) > sigaction(SIGINT, &sa, nullptr); > > std::unique_ptr<EventDispatcher> dispatcher(new QtEventDispatcher()); > - CameraManager *cm = CameraManager::instance(); > + CameraManager *cm = new CameraManager(); > cm->setEventDispatcher(std::move(dispatcher)); > > ret = cm->start(); > @@ -79,5 +79,7 @@ int main(int argc, char **argv) > delete mainWindow; > > cm->stop(); > + delete cm; > + > return ret; > } > diff --git a/test/camera/camera_test.cpp b/test/camera/camera_test.cpp > index 24ff5fe0c64d..0e105414bf46 100644 > --- a/test/camera/camera_test.cpp > +++ b/test/camera/camera_test.cpp > @@ -14,7 +14,7 @@ using namespace std; > > int CameraTest::init() > { > - cm_ = CameraManager::instance(); > + cm_ = new CameraManager(); > > if (cm_->start()) { > cout << "Failed to start camera manager" << endl; > @@ -44,4 +44,5 @@ void CameraTest::cleanup() > } > > cm_->stop(); > + delete cm_; > }; > diff --git a/test/controls/control_list.cpp b/test/controls/control_list.cpp > index c834edc352f5..f1d79ff8fcfd 100644 > --- a/test/controls/control_list.cpp > +++ b/test/controls/control_list.cpp > @@ -21,7 +21,7 @@ class ControlListTest : public Test > protected: > int init() > { > - cm_ = CameraManager::instance(); > + cm_ = new CameraManager(); > > if (cm_->start()) { > cout << "Failed to start camera manager" << endl; > @@ -203,6 +203,7 @@ protected: > } > > cm_->stop(); > + delete cm_; > } > > private: > diff --git a/test/list-cameras.cpp b/test/list-cameras.cpp > index 070cbf2be977..55551d7e7e10 100644 > --- a/test/list-cameras.cpp > +++ b/test/list-cameras.cpp > @@ -20,8 +20,8 @@ class ListTest : public Test > protected: > int init() > { > - cm = CameraManager::instance(); > - cm->start(); > + cm_ = new CameraManager(); > + cm_->start(); > > return 0; > } > @@ -30,7 +30,7 @@ protected: > { > unsigned int count = 0; > > - for (const std::shared_ptr<Camera> &camera : cm->cameras()) { > + for (const std::shared_ptr<Camera> &camera : cm_->cameras()) { > cout << "- " << camera->name() << endl; > count++; > } > @@ -40,11 +40,12 @@ protected: > > void cleanup() > { > - cm->stop(); > + cm_->stop(); > + delete cm_; > } > > private: > - CameraManager *cm; > + CameraManager *cm_; > }; > > TEST_REGISTER(ListTest) > diff --git a/test/pipeline/ipu3/ipu3_pipeline_test.cpp b/test/pipeline/ipu3/ipu3_pipeline_test.cpp > index 1d4cc4d4950b..8bfcd609a071 100644 > --- a/test/pipeline/ipu3/ipu3_pipeline_test.cpp > +++ b/test/pipeline/ipu3/ipu3_pipeline_test.cpp > @@ -92,7 +92,7 @@ int IPU3PipelineTest::init() > > enumerator.reset(nullptr); > > - cameraManager_ = CameraManager::instance(); > + cameraManager_ = new CameraManager(); > ret = cameraManager_->start(); > if (ret) { > cerr << "Failed to start the CameraManager" << endl; > @@ -120,6 +120,7 @@ int IPU3PipelineTest::run() > void IPU3PipelineTest::cleanup() > { > cameraManager_->stop(); > + delete cameraManager_; > } > > TEST_REGISTER(IPU3PipelineTest) > -- > Regards, > > Laurent Pinchart > > _______________________________________________ > libcamera-devel mailing list > libcamera-devel@lists.libcamera.org > https://lists.libcamera.org/listinfo/libcamera-devel
Hi Jacopo, On Mon, Aug 19, 2019 at 10:40:00AM +0200, Jacopo Mondi wrote: > On Sun, Aug 18, 2019 at 04:13:28AM +0300, Laurent Pinchart wrote: > > The CameraManager class is not supposed to be instantiated multiple > > times, which led to a singleton implementation. This requires a global > > instance of the CameraManager, which is destroyed when the global > > destructors are executed. > > > > Relying on global instances causes issues with cleanup, as the order in > > which the global destructors are run can't be controlled. In particular, > > the Android camera HAL implementation ends up destroying the > > CameraHalManager after the CameraManager, which leads to use-after-free > > problems. > > > > To solve this, remove the CameraManager::instance() method and make the > > CameraManager class instantiable directly. Multiple instances are still > > not allowed, and this is enforced by storing the instance pointer > > internally to be checked when an instance is created. > > > > Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> > > --- > > include/libcamera/camera_manager.h | 12 ++++---- > > src/android/camera_hal_manager.cpp | 5 +++- > > src/cam/main.cpp | 8 ++++- > > src/libcamera/camera_manager.cpp | 36 ++++++++++------------- > > src/qcam/main.cpp | 4 ++- > > test/camera/camera_test.cpp | 3 +- > > test/controls/control_list.cpp | 3 +- > > test/list-cameras.cpp | 11 +++---- > > test/pipeline/ipu3/ipu3_pipeline_test.cpp | 3 +- > > 9 files changed, 48 insertions(+), 37 deletions(-) > > [snip] > > > +CameraManager *CameraManager::self_ = nullptr; > > + > > CameraManager::CameraManager() > > : enumerator_(nullptr) > > { > > + if (self_) > > + LOG(Camera, Fatal) > > + << "Multiple CameraManager objects are not allowed"; > > + > > + self_ = this; > > This is a very weak guarantee that the CameraManager would not be > created twice... Note that a fatal error message causes an std::abort() (in all builds, including release builds), so it's not *that* weak :-) > I was wondering, our previous singleton implementation was based on > lazy evaluation, by returning a statically allocated CameraManager instance: > > CameraManager *CameraManager::instance() > { > static CameraManager manager; > return &manager; > } > > This mean it gets deleted at program termination time causing the > issue you're here trying to solve. > > What if the make the manager creation dynamic instead and provide a > static destructor method, that applications could call to guarantee > the manager is deleted at the right time? > > Would something like this work in your opinion? I've considered various options when working on this patch. What I don't like about an explicit destroy() method like proposed below is that it breaks the symmetry between construction and destruction. The instance() method dilutes the responsibility of creating the camera manager instance (the first call creates it, and the callers don't know if they're the first caller or not, which is the main purpose of a singleton), but requires giving the responsibility for deleting the instance to one particular actor in the system. I think it would be best to give the responsibility to create and destroy the camera manager explicitly. This being said, if that ends up being helpful, we could restore the instance() method but simply make it return self_. The method would thus return nullptr before the camera manager instance is constructed, or after it gets deleted. For now we don't have a need for that so I've simply dropped the instance() method. > diff --git a/include/libcamera/camera_manager.h b/include/libcamera/camera_manager.h > index ff7d4c7c6745..a29a24f5e37a 100644 > --- a/include/libcamera/camera_manager.h > +++ b/include/libcamera/camera_manager.h > @@ -33,6 +33,7 @@ public: > void removeCamera(Camera *camera); > > static CameraManager *instance(); > + static void destroy(); > static const std::string &version() { return version_; } > > void setEventDispatcher(std::unique_ptr<EventDispatcher> dispatcher); > @@ -49,6 +50,8 @@ private: > std::vector<std::shared_ptr<Camera>> cameras_; > > static const std::string version_; > + > + static CameraManager *manager_; > }; > > } /* namespace libcamera */ > diff --git a/src/libcamera/camera_manager.cpp b/src/libcamera/camera_manager.cpp > index 4a880684c5cb..ed175ccc5860 100644 > --- a/src/libcamera/camera_manager.cpp > +++ b/src/libcamera/camera_manager.cpp > @@ -26,6 +26,8 @@ namespace libcamera { > > LOG_DEFINE_CATEGORY(Camera) > > +CameraManager *CameraManager::manager_ = nullptr; > + > /** > * \class CameraManager > * \brief Provide access and manage all cameras in the system > @@ -223,8 +225,16 @@ void CameraManager::removeCamera(Camera *camera) > */ > CameraManager *CameraManager::instance() > { > - static CameraManager manager; > - return &manager; > + if (!manager_) > + manager_ = new CameraManager(); > + > + return manager_; > +} > + > +void CameraManager::destroy() > +{ > + delete manager_; > + manager_ = nullptr; > } > > /** > > > } > > > > CameraManager::~CameraManager() > > { > > + self_ = nullptr; > > } > > > > /** > > @@ -212,21 +223,6 @@ void CameraManager::removeCamera(Camera *camera) > > } > > } > > > > -/** > > - * \brief Retrieve the camera manager instance > > - * > > - * The CameraManager is a singleton and can't be constructed manually. This > > - * function shall instead be used to retrieve the single global instance of the > > - * manager. > > - * > > - * \return The camera manager instance > > - */ > > -CameraManager *CameraManager::instance() > > -{ > > - static CameraManager manager; > > - return &manager; > > -} > > - > > /** > > * \fn const std::string &CameraManager::version() > > * \brief Retrieve the libcamera version string > > diff --git a/src/qcam/main.cpp b/src/qcam/main.cpp > > index 05d3b77e9edb..a7ff5c52663b 100644 > > --- a/src/qcam/main.cpp > > +++ b/src/qcam/main.cpp > > @@ -63,7 +63,7 @@ int main(int argc, char **argv) > > sigaction(SIGINT, &sa, nullptr); > > > > std::unique_ptr<EventDispatcher> dispatcher(new QtEventDispatcher()); > > - CameraManager *cm = CameraManager::instance(); > > + CameraManager *cm = new CameraManager(); > > cm->setEventDispatcher(std::move(dispatcher)); > > > > ret = cm->start(); > > @@ -79,5 +79,7 @@ int main(int argc, char **argv) > > delete mainWindow; > > > > cm->stop(); > > + delete cm; > > + > > return ret; > > } > > diff --git a/test/camera/camera_test.cpp b/test/camera/camera_test.cpp > > index 24ff5fe0c64d..0e105414bf46 100644 > > --- a/test/camera/camera_test.cpp > > +++ b/test/camera/camera_test.cpp > > @@ -14,7 +14,7 @@ using namespace std; > > > > int CameraTest::init() > > { > > - cm_ = CameraManager::instance(); > > + cm_ = new CameraManager(); > > > > if (cm_->start()) { > > cout << "Failed to start camera manager" << endl; > > @@ -44,4 +44,5 @@ void CameraTest::cleanup() > > } > > > > cm_->stop(); > > + delete cm_; > > }; > > diff --git a/test/controls/control_list.cpp b/test/controls/control_list.cpp > > index c834edc352f5..f1d79ff8fcfd 100644 > > --- a/test/controls/control_list.cpp > > +++ b/test/controls/control_list.cpp > > @@ -21,7 +21,7 @@ class ControlListTest : public Test > > protected: > > int init() > > { > > - cm_ = CameraManager::instance(); > > + cm_ = new CameraManager(); > > > > if (cm_->start()) { > > cout << "Failed to start camera manager" << endl; > > @@ -203,6 +203,7 @@ protected: > > } > > > > cm_->stop(); > > + delete cm_; > > } > > > > private: > > diff --git a/test/list-cameras.cpp b/test/list-cameras.cpp > > index 070cbf2be977..55551d7e7e10 100644 > > --- a/test/list-cameras.cpp > > +++ b/test/list-cameras.cpp > > @@ -20,8 +20,8 @@ class ListTest : public Test > > protected: > > int init() > > { > > - cm = CameraManager::instance(); > > - cm->start(); > > + cm_ = new CameraManager(); > > + cm_->start(); > > > > return 0; > > } > > @@ -30,7 +30,7 @@ protected: > > { > > unsigned int count = 0; > > > > - for (const std::shared_ptr<Camera> &camera : cm->cameras()) { > > + for (const std::shared_ptr<Camera> &camera : cm_->cameras()) { > > cout << "- " << camera->name() << endl; > > count++; > > } > > @@ -40,11 +40,12 @@ protected: > > > > void cleanup() > > { > > - cm->stop(); > > + cm_->stop(); > > + delete cm_; > > } > > > > private: > > - CameraManager *cm; > > + CameraManager *cm_; > > }; > > > > TEST_REGISTER(ListTest) > > diff --git a/test/pipeline/ipu3/ipu3_pipeline_test.cpp b/test/pipeline/ipu3/ipu3_pipeline_test.cpp > > index 1d4cc4d4950b..8bfcd609a071 100644 > > --- a/test/pipeline/ipu3/ipu3_pipeline_test.cpp > > +++ b/test/pipeline/ipu3/ipu3_pipeline_test.cpp > > @@ -92,7 +92,7 @@ int IPU3PipelineTest::init() > > > > enumerator.reset(nullptr); > > > > - cameraManager_ = CameraManager::instance(); > > + cameraManager_ = new CameraManager(); > > ret = cameraManager_->start(); > > if (ret) { > > cerr << "Failed to start the CameraManager" << endl; > > @@ -120,6 +120,7 @@ int IPU3PipelineTest::run() > > void IPU3PipelineTest::cleanup() > > { > > cameraManager_->stop(); > > + delete cameraManager_; > > } > > > > TEST_REGISTER(IPU3PipelineTest)
Hi Laurent, On Mon, Aug 19, 2019 at 06:37:52PM +0300, Laurent Pinchart wrote: > Hi Jacopo, > > On Mon, Aug 19, 2019 at 10:40:00AM +0200, Jacopo Mondi wrote: > > On Sun, Aug 18, 2019 at 04:13:28AM +0300, Laurent Pinchart wrote: > > > The CameraManager class is not supposed to be instantiated multiple > > > times, which led to a singleton implementation. This requires a global > > > instance of the CameraManager, which is destroyed when the global > > > destructors are executed. > > > > > > Relying on global instances causes issues with cleanup, as the order in > > > which the global destructors are run can't be controlled. In particular, > > > the Android camera HAL implementation ends up destroying the > > > CameraHalManager after the CameraManager, which leads to use-after-free > > > problems. > > > > > > To solve this, remove the CameraManager::instance() method and make the > > > CameraManager class instantiable directly. Multiple instances are still > > > not allowed, and this is enforced by storing the instance pointer > > > internally to be checked when an instance is created. > > > > > > Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> > > > --- > > > include/libcamera/camera_manager.h | 12 ++++---- > > > src/android/camera_hal_manager.cpp | 5 +++- > > > src/cam/main.cpp | 8 ++++- > > > src/libcamera/camera_manager.cpp | 36 ++++++++++------------- > > > src/qcam/main.cpp | 4 ++- > > > test/camera/camera_test.cpp | 3 +- > > > test/controls/control_list.cpp | 3 +- > > > test/list-cameras.cpp | 11 +++---- > > > test/pipeline/ipu3/ipu3_pipeline_test.cpp | 3 +- > > > 9 files changed, 48 insertions(+), 37 deletions(-) > > > > [snip] > > > > > +CameraManager *CameraManager::self_ = nullptr; > > > + > > > CameraManager::CameraManager() > > > : enumerator_(nullptr) > > > { > > > + if (self_) > > > + LOG(Camera, Fatal) > > > + << "Multiple CameraManager objects are not allowed"; > > > + > > > + self_ = this; > > > > This is a very weak guarantee that the CameraManager would not be > > created twice... > > Note that a fatal error message causes an std::abort() (in all builds, > including release builds), so it's not *that* weak :-) > Oh I see, I thought it applied to debug builds only (and I initially missed it was "Fatal") > > I was wondering, our previous singleton implementation was based on > > lazy evaluation, by returning a statically allocated CameraManager instance: > > > > CameraManager *CameraManager::instance() > > { > > static CameraManager manager; > > return &manager; > > } > > > > This mean it gets deleted at program termination time causing the > > issue you're here trying to solve. > > > > What if the make the manager creation dynamic instead and provide a > > static destructor method, that applications could call to guarantee > > the manager is deleted at the right time? > > > > Would something like this work in your opinion? > > I've considered various options when working on this patch. What I don't > like about an explicit destroy() method like proposed below is that it > breaks the symmetry between construction and destruction. The instance() > method dilutes the responsibility of creating the camera manager > instance (the first call creates it, and the callers don't know if > they're the first caller or not, which is the main purpose of a > singleton), but requires giving the responsibility for deleting the > instance to one particular actor in the system. I think it would be best > to give the responsibility to create and destroy the camera manager > explicitly. I understand, and it would probably create a more confused API to deal with. > > This being said, if that ends up being helpful, we could restore the > instance() method but simply make it return self_. The method would thus > return nullptr before the camera manager instance is constructed, or > after it gets deleted. For now we don't have a need for that so I've > simply dropped the instance() method. > As long as application instantiating multiple camera manager instance are loudly notified (and crashing is loud enough), I'm fine with this approach. Reviewed-by: Jacopo Mondi <jacopo@jmondi.org> Thanks j > > diff --git a/include/libcamera/camera_manager.h b/include/libcamera/camera_manager.h > > index ff7d4c7c6745..a29a24f5e37a 100644 > > --- a/include/libcamera/camera_manager.h > > +++ b/include/libcamera/camera_manager.h > > @@ -33,6 +33,7 @@ public: > > void removeCamera(Camera *camera); > > > > static CameraManager *instance(); > > + static void destroy(); > > static const std::string &version() { return version_; } > > > > void setEventDispatcher(std::unique_ptr<EventDispatcher> dispatcher); > > @@ -49,6 +50,8 @@ private: > > std::vector<std::shared_ptr<Camera>> cameras_; > > > > static const std::string version_; > > + > > + static CameraManager *manager_; > > }; > > > > } /* namespace libcamera */ > > diff --git a/src/libcamera/camera_manager.cpp b/src/libcamera/camera_manager.cpp > > index 4a880684c5cb..ed175ccc5860 100644 > > --- a/src/libcamera/camera_manager.cpp > > +++ b/src/libcamera/camera_manager.cpp > > @@ -26,6 +26,8 @@ namespace libcamera { > > > > LOG_DEFINE_CATEGORY(Camera) > > > > +CameraManager *CameraManager::manager_ = nullptr; > > + > > /** > > * \class CameraManager > > * \brief Provide access and manage all cameras in the system > > @@ -223,8 +225,16 @@ void CameraManager::removeCamera(Camera *camera) > > */ > > CameraManager *CameraManager::instance() > > { > > - static CameraManager manager; > > - return &manager; > > + if (!manager_) > > + manager_ = new CameraManager(); > > + > > + return manager_; > > +} > > + > > +void CameraManager::destroy() > > +{ > > + delete manager_; > > + manager_ = nullptr; > > } > > > > /** > > > > > } > > > > > > CameraManager::~CameraManager() > > > { > > > + self_ = nullptr; > > > } > > > > > > /** > > > @@ -212,21 +223,6 @@ void CameraManager::removeCamera(Camera *camera) > > > } > > > } > > > > > > -/** > > > - * \brief Retrieve the camera manager instance > > > - * > > > - * The CameraManager is a singleton and can't be constructed manually. This > > > - * function shall instead be used to retrieve the single global instance of the > > > - * manager. > > > - * > > > - * \return The camera manager instance > > > - */ > > > -CameraManager *CameraManager::instance() > > > -{ > > > - static CameraManager manager; > > > - return &manager; > > > -} > > > - > > > /** > > > * \fn const std::string &CameraManager::version() > > > * \brief Retrieve the libcamera version string > > > diff --git a/src/qcam/main.cpp b/src/qcam/main.cpp > > > index 05d3b77e9edb..a7ff5c52663b 100644 > > > --- a/src/qcam/main.cpp > > > +++ b/src/qcam/main.cpp > > > @@ -63,7 +63,7 @@ int main(int argc, char **argv) > > > sigaction(SIGINT, &sa, nullptr); > > > > > > std::unique_ptr<EventDispatcher> dispatcher(new QtEventDispatcher()); > > > - CameraManager *cm = CameraManager::instance(); > > > + CameraManager *cm = new CameraManager(); > > > cm->setEventDispatcher(std::move(dispatcher)); > > > > > > ret = cm->start(); > > > @@ -79,5 +79,7 @@ int main(int argc, char **argv) > > > delete mainWindow; > > > > > > cm->stop(); > > > + delete cm; > > > + > > > return ret; > > > } > > > diff --git a/test/camera/camera_test.cpp b/test/camera/camera_test.cpp > > > index 24ff5fe0c64d..0e105414bf46 100644 > > > --- a/test/camera/camera_test.cpp > > > +++ b/test/camera/camera_test.cpp > > > @@ -14,7 +14,7 @@ using namespace std; > > > > > > int CameraTest::init() > > > { > > > - cm_ = CameraManager::instance(); > > > + cm_ = new CameraManager(); > > > > > > if (cm_->start()) { > > > cout << "Failed to start camera manager" << endl; > > > @@ -44,4 +44,5 @@ void CameraTest::cleanup() > > > } > > > > > > cm_->stop(); > > > + delete cm_; > > > }; > > > diff --git a/test/controls/control_list.cpp b/test/controls/control_list.cpp > > > index c834edc352f5..f1d79ff8fcfd 100644 > > > --- a/test/controls/control_list.cpp > > > +++ b/test/controls/control_list.cpp > > > @@ -21,7 +21,7 @@ class ControlListTest : public Test > > > protected: > > > int init() > > > { > > > - cm_ = CameraManager::instance(); > > > + cm_ = new CameraManager(); > > > > > > if (cm_->start()) { > > > cout << "Failed to start camera manager" << endl; > > > @@ -203,6 +203,7 @@ protected: > > > } > > > > > > cm_->stop(); > > > + delete cm_; > > > } > > > > > > private: > > > diff --git a/test/list-cameras.cpp b/test/list-cameras.cpp > > > index 070cbf2be977..55551d7e7e10 100644 > > > --- a/test/list-cameras.cpp > > > +++ b/test/list-cameras.cpp > > > @@ -20,8 +20,8 @@ class ListTest : public Test > > > protected: > > > int init() > > > { > > > - cm = CameraManager::instance(); > > > - cm->start(); > > > + cm_ = new CameraManager(); > > > + cm_->start(); > > > > > > return 0; > > > } > > > @@ -30,7 +30,7 @@ protected: > > > { > > > unsigned int count = 0; > > > > > > - for (const std::shared_ptr<Camera> &camera : cm->cameras()) { > > > + for (const std::shared_ptr<Camera> &camera : cm_->cameras()) { > > > cout << "- " << camera->name() << endl; > > > count++; > > > } > > > @@ -40,11 +40,12 @@ protected: > > > > > > void cleanup() > > > { > > > - cm->stop(); > > > + cm_->stop(); > > > + delete cm_; > > > } > > > > > > private: > > > - CameraManager *cm; > > > + CameraManager *cm_; > > > }; > > > > > > TEST_REGISTER(ListTest) > > > diff --git a/test/pipeline/ipu3/ipu3_pipeline_test.cpp b/test/pipeline/ipu3/ipu3_pipeline_test.cpp > > > index 1d4cc4d4950b..8bfcd609a071 100644 > > > --- a/test/pipeline/ipu3/ipu3_pipeline_test.cpp > > > +++ b/test/pipeline/ipu3/ipu3_pipeline_test.cpp > > > @@ -92,7 +92,7 @@ int IPU3PipelineTest::init() > > > > > > enumerator.reset(nullptr); > > > > > > - cameraManager_ = CameraManager::instance(); > > > + cameraManager_ = new CameraManager(); > > > ret = cameraManager_->start(); > > > if (ret) { > > > cerr << "Failed to start the CameraManager" << endl; > > > @@ -120,6 +120,7 @@ int IPU3PipelineTest::run() > > > void IPU3PipelineTest::cleanup() > > > { > > > cameraManager_->stop(); > > > + delete cameraManager_; > > > } > > > > > > TEST_REGISTER(IPU3PipelineTest) > > -- > Regards, > > Laurent Pinchart
diff --git a/include/libcamera/camera_manager.h b/include/libcamera/camera_manager.h index ff7d4c7c6745..8331898c4219 100644 --- a/include/libcamera/camera_manager.h +++ b/include/libcamera/camera_manager.h @@ -23,6 +23,11 @@ class PipelineHandler; class CameraManager : public Object { public: + CameraManager(); + CameraManager(const CameraManager &) = delete; + CameraManager &operator=(const CameraManager &) = delete; + ~CameraManager(); + int start(); void stop(); @@ -32,23 +37,18 @@ public: void addCamera(std::shared_ptr<Camera> camera); void removeCamera(Camera *camera); - static CameraManager *instance(); static const std::string &version() { return version_; } void setEventDispatcher(std::unique_ptr<EventDispatcher> dispatcher); EventDispatcher *eventDispatcher(); private: - CameraManager(); - CameraManager(const CameraManager &) = delete; - CameraManager &operator=(const CameraManager &) = delete; - ~CameraManager(); - std::unique_ptr<DeviceEnumerator> enumerator_; std::vector<std::shared_ptr<PipelineHandler>> pipes_; std::vector<std::shared_ptr<Camera>> cameras_; static const std::string version_; + static CameraManager *self_; }; } /* namespace libcamera */ diff --git a/src/android/camera_hal_manager.cpp b/src/android/camera_hal_manager.cpp index cf981720bca4..22f0323b3ff0 100644 --- a/src/android/camera_hal_manager.cpp +++ b/src/android/camera_hal_manager.cpp @@ -59,7 +59,7 @@ void CameraHalManager::run() * order to bind them to the camera HAL manager thread that * executes the event dispatcher. */ - cameraManager_ = libcamera::CameraManager::instance(); + cameraManager_ = new CameraManager(); int ret = cameraManager_->start(); if (ret) { @@ -93,7 +93,10 @@ void CameraHalManager::run() /* Clean up the resources we have allocated. */ proxies_.clear(); + cameraManager_->stop(); + delete cameraManager_; + cameraManager_ = nullptr; } CameraProxy *CameraHalManager::open(unsigned int id, diff --git a/src/cam/main.cpp b/src/cam/main.cpp index 77bb20e9622e..9d99f5587cbb 100644 --- a/src/cam/main.cpp +++ b/src/cam/main.cpp @@ -23,6 +23,7 @@ class CamApp { public: CamApp(); + ~CamApp(); static CamApp *instance(); @@ -54,6 +55,11 @@ CamApp::CamApp() CamApp::app_ = this; } +CamApp::~CamApp() +{ + delete cm_; +} + CamApp *CamApp::instance() { return CamApp::app_; @@ -67,7 +73,7 @@ int CamApp::init(int argc, char **argv) if (ret < 0) return ret; - cm_ = CameraManager::instance(); + cm_ = new CameraManager(); ret = cm_->start(); if (ret) { diff --git a/src/libcamera/camera_manager.cpp b/src/libcamera/camera_manager.cpp index 4a880684c5cb..12cb5a0be859 100644 --- a/src/libcamera/camera_manager.cpp +++ b/src/libcamera/camera_manager.cpp @@ -35,11 +35,14 @@ LOG_DEFINE_CATEGORY(Camera) * in the system to applications. The manager owns all Camera objects and * handles hot-plugging and hot-unplugging to manage the lifetime of cameras. * - * To interact with libcamera, an application retrieves the camera manager - * instance with CameraManager::instance(). The manager is initially stopped, - * and shall be configured before being started. In particular a custom event - * dispatcher shall be installed if needed with - * CameraManager::setEventDispatcher(). + * To interact with libcamera, an application starts by creating a camera + * manager instance. Only a single instance of the camera manager may exist at + * a time. Attempting to create a second instance without first deleting the + * existing instance results in undefined behaviour. + * + * The manager is initially stopped, and shall be configured before being + * started. In particular a custom event dispatcher shall be installed if + * needed with CameraManager::setEventDispatcher(). * * Once the camera manager is configured, it shall be started with start(). * This will enumerate all the cameras present in the system, which can then be @@ -56,13 +59,21 @@ LOG_DEFINE_CATEGORY(Camera) * removed due to hot-unplug. */ +CameraManager *CameraManager::self_ = nullptr; + CameraManager::CameraManager() : enumerator_(nullptr) { + if (self_) + LOG(Camera, Fatal) + << "Multiple CameraManager objects are not allowed"; + + self_ = this; } CameraManager::~CameraManager() { + self_ = nullptr; } /** @@ -212,21 +223,6 @@ void CameraManager::removeCamera(Camera *camera) } } -/** - * \brief Retrieve the camera manager instance - * - * The CameraManager is a singleton and can't be constructed manually. This - * function shall instead be used to retrieve the single global instance of the - * manager. - * - * \return The camera manager instance - */ -CameraManager *CameraManager::instance() -{ - static CameraManager manager; - return &manager; -} - /** * \fn const std::string &CameraManager::version() * \brief Retrieve the libcamera version string diff --git a/src/qcam/main.cpp b/src/qcam/main.cpp index 05d3b77e9edb..a7ff5c52663b 100644 --- a/src/qcam/main.cpp +++ b/src/qcam/main.cpp @@ -63,7 +63,7 @@ int main(int argc, char **argv) sigaction(SIGINT, &sa, nullptr); std::unique_ptr<EventDispatcher> dispatcher(new QtEventDispatcher()); - CameraManager *cm = CameraManager::instance(); + CameraManager *cm = new CameraManager(); cm->setEventDispatcher(std::move(dispatcher)); ret = cm->start(); @@ -79,5 +79,7 @@ int main(int argc, char **argv) delete mainWindow; cm->stop(); + delete cm; + return ret; } diff --git a/test/camera/camera_test.cpp b/test/camera/camera_test.cpp index 24ff5fe0c64d..0e105414bf46 100644 --- a/test/camera/camera_test.cpp +++ b/test/camera/camera_test.cpp @@ -14,7 +14,7 @@ using namespace std; int CameraTest::init() { - cm_ = CameraManager::instance(); + cm_ = new CameraManager(); if (cm_->start()) { cout << "Failed to start camera manager" << endl; @@ -44,4 +44,5 @@ void CameraTest::cleanup() } cm_->stop(); + delete cm_; }; diff --git a/test/controls/control_list.cpp b/test/controls/control_list.cpp index c834edc352f5..f1d79ff8fcfd 100644 --- a/test/controls/control_list.cpp +++ b/test/controls/control_list.cpp @@ -21,7 +21,7 @@ class ControlListTest : public Test protected: int init() { - cm_ = CameraManager::instance(); + cm_ = new CameraManager(); if (cm_->start()) { cout << "Failed to start camera manager" << endl; @@ -203,6 +203,7 @@ protected: } cm_->stop(); + delete cm_; } private: diff --git a/test/list-cameras.cpp b/test/list-cameras.cpp index 070cbf2be977..55551d7e7e10 100644 --- a/test/list-cameras.cpp +++ b/test/list-cameras.cpp @@ -20,8 +20,8 @@ class ListTest : public Test protected: int init() { - cm = CameraManager::instance(); - cm->start(); + cm_ = new CameraManager(); + cm_->start(); return 0; } @@ -30,7 +30,7 @@ protected: { unsigned int count = 0; - for (const std::shared_ptr<Camera> &camera : cm->cameras()) { + for (const std::shared_ptr<Camera> &camera : cm_->cameras()) { cout << "- " << camera->name() << endl; count++; } @@ -40,11 +40,12 @@ protected: void cleanup() { - cm->stop(); + cm_->stop(); + delete cm_; } private: - CameraManager *cm; + CameraManager *cm_; }; TEST_REGISTER(ListTest) diff --git a/test/pipeline/ipu3/ipu3_pipeline_test.cpp b/test/pipeline/ipu3/ipu3_pipeline_test.cpp index 1d4cc4d4950b..8bfcd609a071 100644 --- a/test/pipeline/ipu3/ipu3_pipeline_test.cpp +++ b/test/pipeline/ipu3/ipu3_pipeline_test.cpp @@ -92,7 +92,7 @@ int IPU3PipelineTest::init() enumerator.reset(nullptr); - cameraManager_ = CameraManager::instance(); + cameraManager_ = new CameraManager(); ret = cameraManager_->start(); if (ret) { cerr << "Failed to start the CameraManager" << endl; @@ -120,6 +120,7 @@ int IPU3PipelineTest::run() void IPU3PipelineTest::cleanup() { cameraManager_->stop(); + delete cameraManager_; } TEST_REGISTER(IPU3PipelineTest)
The CameraManager class is not supposed to be instantiated multiple times, which led to a singleton implementation. This requires a global instance of the CameraManager, which is destroyed when the global destructors are executed. Relying on global instances causes issues with cleanup, as the order in which the global destructors are run can't be controlled. In particular, the Android camera HAL implementation ends up destroying the CameraHalManager after the CameraManager, which leads to use-after-free problems. To solve this, remove the CameraManager::instance() method and make the CameraManager class instantiable directly. Multiple instances are still not allowed, and this is enforced by storing the instance pointer internally to be checked when an instance is created. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> --- include/libcamera/camera_manager.h | 12 ++++---- src/android/camera_hal_manager.cpp | 5 +++- src/cam/main.cpp | 8 ++++- src/libcamera/camera_manager.cpp | 36 ++++++++++------------- src/qcam/main.cpp | 4 ++- test/camera/camera_test.cpp | 3 +- test/controls/control_list.cpp | 3 +- test/list-cameras.cpp | 11 +++---- test/pipeline/ipu3/ipu3_pipeline_test.cpp | 3 +- 9 files changed, 48 insertions(+), 37 deletions(-)