From d505bd5360cc1681ae639c19cc48bdd28d24d9f7 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Barnab=C3=A1s=20P=C5=91cze?= Date: Thu, 6 Feb 2025 15:59:42 +0100 Subject: libcamera: camera_manager: Do not emit signals while holding lock MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Both `CameraManager::Private::{add,remove}Camera()` emit the `camera{Added,Removed}` signals, respectively, while holding the lock protecting the list of cameras. This is problematic because if a callback tries to call `cameras()`, then the same (non-recursive) lock would be locked again. Furthermore, there is no real need to hold the lock while user code is running, so release the lock as soon as possible. Signed-off-by: Barnabás Pőcze Reviewed-by: Harvey Yang Reviewed-by: Laurent Pinchart Reviewed-by: Kieran Bingham --- src/libcamera/camera_manager.cpp | 44 +++++++++++++++++++++------------------- 1 file changed, 23 insertions(+), 21 deletions(-) (limited to 'src') diff --git a/src/libcamera/camera_manager.cpp b/src/libcamera/camera_manager.cpp index 87e6717e..400109f1 100644 --- a/src/libcamera/camera_manager.cpp +++ b/src/libcamera/camera_manager.cpp @@ -202,24 +202,24 @@ void CameraManager::Private::addCamera(std::shared_ptr camera) { ASSERT(Thread::current() == this); - MutexLocker locker(mutex_); + { + MutexLocker locker(mutex_); - for (const std::shared_ptr &c : cameras_) { - if (c->id() == camera->id()) { - LOG(Camera, Fatal) - << "Trying to register a camera with a duplicated ID '" - << camera->id() << "'"; - return; + for (const std::shared_ptr &c : cameras_) { + if (c->id() == camera->id()) { + LOG(Camera, Fatal) + << "Trying to register a camera with a duplicated ID '" + << camera->id() << "'"; + return; + } } - } - cameras_.push_back(std::move(camera)); - - unsigned int index = cameras_.size() - 1; + cameras_.push_back(camera); + } /* Report the addition to the public signal */ CameraManager *const o = LIBCAMERA_O_PTR(); - o->cameraAdded.emit(cameras_[index]); + o->cameraAdded.emit(camera); } /** @@ -236,20 +236,22 @@ void CameraManager::Private::removeCamera(std::shared_ptr camera) { ASSERT(Thread::current() == this); - MutexLocker locker(mutex_); + { + MutexLocker locker(mutex_); - auto iter = std::find_if(cameras_.begin(), cameras_.end(), - [camera](std::shared_ptr &c) { - return c.get() == camera.get(); - }); - if (iter == cameras_.end()) - return; + auto iter = std::find_if(cameras_.begin(), cameras_.end(), + [camera](std::shared_ptr &c) { + return c.get() == camera.get(); + }); + if (iter == cameras_.end()) + return; + + cameras_.erase(iter); + } LOG(Camera, Debug) << "Unregistering camera '" << camera->id() << "'"; - cameras_.erase(iter); - /* Report the removal to the public signal */ CameraManager *const o = LIBCAMERA_O_PTR(); o->cameraRemoved.emit(camera); -- cgit v1.2.1