[libcamera-devel] [PATCH v2 1/7] IPAManager: make IPAManager lifetime explicitly managed

[Paul Elder]

If any ipa_context instances are destroyed after the IPAManager is
destroyed, then a segfault will occur, since the modules have been
unloaded by the IPAManager and the context function pointers have been
freed.

Fix this by making the lifetime of the IPAManager explicit, and make the
CameraManager construct and deconstruct (automatically, via a unique
pointer) the IPAManager.

Also update the IPA interface test to do the construction and
deconstruction of the IPAManager, as it does not use the CameraManager.

Signed-off-by: Paul Elder <paul.elder at ideasonboard.com>

---
Changes in v2: Move the IPAManager instance into
	       CameraManager::Private from CameraManager
---
 include/libcamera/camera_manager.h       |  1 -
 include/libcamera/internal/ipa_manager.h |  6 ++++--
 src/libcamera/camera_manager.cpp         |  3 +++
 src/libcamera/ipa_manager.cpp            | 20 ++++++++++++++++++--
 test/ipa/ipa_interface_test.cpp          |  5 +++++
 5 files changed, 30 insertions(+), 5 deletions(-)

diff --git a/include/libcamera/camera_manager.h b/include/libcamera/camera_manager.h
index 079f848a..00658a70 100644
--- a/include/libcamera/camera_manager.h
+++ b/include/libcamera/camera_manager.h
@@ -18,7 +18,6 @@ namespace libcamera {
 
 class Camera;
 class EventDispatcher;
-
 class CameraManager : public Object
 {
 public:
diff --git a/include/libcamera/internal/ipa_manager.h b/include/libcamera/internal/ipa_manager.h
index 16d74291..43f700d3 100644
--- a/include/libcamera/internal/ipa_manager.h
+++ b/include/libcamera/internal/ipa_manager.h
@@ -22,6 +22,9 @@ namespace libcamera {
 class IPAManager
 {
 public:
+	IPAManager();
+	~IPAManager();
+
 	static IPAManager *instance();
 
 	std::unique_ptr<IPAProxy> createIPA(PipelineHandler *pipe,
@@ -29,8 +32,7 @@ public:
 					    uint32_t minVersion);
 
 private:
-	IPAManager();
-	~IPAManager();
+	static IPAManager *self_;
 
 	void parseDir(const char *libDir, unsigned int maxDepth,
 		      std::vector<std::string> &files);
diff --git a/src/libcamera/camera_manager.cpp b/src/libcamera/camera_manager.cpp
index 849377ad..da806fa7 100644
--- a/src/libcamera/camera_manager.cpp
+++ b/src/libcamera/camera_manager.cpp
@@ -15,6 +15,7 @@
 
 #include "libcamera/internal/device_enumerator.h"
 #include "libcamera/internal/event_dispatcher_poll.h"
+#include "libcamera/internal/ipa_manager.h"
 #include "libcamera/internal/log.h"
 #include "libcamera/internal/pipeline_handler.h"
 #include "libcamera/internal/thread.h"
@@ -63,6 +64,8 @@ private:
 
 	std::vector<std::shared_ptr<PipelineHandler>> pipes_;
 	std::unique_ptr<DeviceEnumerator> enumerator_;
+
+	IPAManager ipaManager_;
 };
 
 CameraManager::Private::Private(CameraManager *cm)
diff --git a/src/libcamera/ipa_manager.cpp b/src/libcamera/ipa_manager.cpp
index 505cf610..abb681a3 100644
--- a/src/libcamera/ipa_manager.cpp
+++ b/src/libcamera/ipa_manager.cpp
@@ -93,8 +93,21 @@ LOG_DEFINE_CATEGORY(IPAManager)
  * plain C API, or to transmit the data to the isolated process through IPC.
  */
 
+IPAManager *IPAManager::self_ = nullptr;
+
+/**
+ * \brief Construct an IPAManager instance
+ *
+ * The IPAManager class is meant to only be instantiated once, by the
+ * CameraManager. Pipeline handlers shall use the instance() function to access
+ * the IPAManager instance.
+ */
 IPAManager::IPAManager()
 {
+	if (self_)
+		LOG(IPAManager, Fatal)
+			<< "Multiple IPAManager objects are not allowed";
+
 	unsigned int ipaCount = 0;
 
 	/* User-specified paths take precedence. */
@@ -134,12 +147,16 @@ IPAManager::IPAManager()
 	if (!ipaCount)
 		LOG(IPAManager, Warning)
 			<< "No IPA found in '" IPA_MODULE_DIR "'";
+
+	self_ = this;
 }
 
 IPAManager::~IPAManager()
 {
 	for (IPAModule *module : modules_)
 		delete module;
+
+	self_ = nullptr;
 }
 
 /**
@@ -153,8 +170,7 @@ IPAManager::~IPAManager()
  */
 IPAManager *IPAManager::instance()
 {
-	static IPAManager ipaManager;
-	return &ipaManager;
+	return self_;
 }
 
 /**
diff --git a/test/ipa/ipa_interface_test.cpp b/test/ipa/ipa_interface_test.cpp
index 2f02af49..153493ba 100644
--- a/test/ipa/ipa_interface_test.cpp
+++ b/test/ipa/ipa_interface_test.cpp
@@ -39,11 +39,15 @@ public:
 	~IPAInterfaceTest()
 	{
 		delete notifier_;
+		ipa_.reset();
+		ipaManager_.reset();
 	}
 
 protected:
 	int init() override
 	{
+		ipaManager_ = make_unique<IPAManager>();
+
 		/* Create a pipeline handler for vimc. */
 		std::vector<PipelineHandlerFactory *> &factories =
 			PipelineHandlerFactory::factories();
@@ -161,6 +165,7 @@ private:
 
 	std::shared_ptr<PipelineHandler> pipe_;
 	std::unique_ptr<IPAProxy> ipa_;
+	std::unique_ptr<IPAManager> ipaManager_;
 	enum IPAOperationCode trace_;
 	EventNotifier *notifier_;
 	int fd_;
-- 
2.20.1