libcamera: Don't ignore the return value of read() and write()

The glibc read() and write() functions are defined with the
__warn_unused_result__ attribute when using FORTIFY_SOURCE. Don't ignore
their return value.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

2 files changed, 26 insertions, 4 deletions

diff --git a/src/libcamera/event_dispatcher_poll.cpp b/src/libcamera/event_dispatcher_poll.cpp
index 1f0f352a..0ff99fce 100644
--- a/src/libcamera/event_dispatcher_poll.cpp
+++ b/src/libcamera/event_dispatcher_poll.cpp
@@ -162,7 +162,14 @@ void EventDispatcherPoll::processEvents()
 void EventDispatcherPoll::interrupt()
 {
 	uint64_t value = 1;
-	write(eventfd_, &value, sizeof(value));
+	ssize_t ret = write(eventfd_, &value, sizeof(value));
+	if (ret != sizeof(value)) {
+		if (ret < 0)
+			ret = -errno;
+		LOG(Event, Error)
+			<< "Failed to interrupt event dispatcher ("
+			<< ret << ")";
+	}
 }
 
 short EventDispatcherPoll::EventNotifierSetPoll::events() const
@@ -214,7 +221,13 @@ void EventDispatcherPoll::processInterrupt(const struct pollfd &pfd)
 		return;
 
 	uint64_t value;
-	read(eventfd_, &value, sizeof(value));
+	ssize_t ret = read(eventfd_, &value, sizeof(value));
+	if (ret != sizeof(value)) {
+		if (ret < 0)
+			ret = -errno;
+		LOG(Event, Error)
+			<< "Failed to process interrupt (" << ret << ")";
+	}
 }
 
 void EventDispatcherPoll::processNotifiers(const std::vector<struct pollfd> &pollfds)
diff --git a/test/event.cpp b/test/event.cpp
index 52bc0c7e..9bd87615 100644
--- a/test/event.cpp
+++ b/test/event.cpp
@@ -38,6 +38,7 @@ protected:
 		EventDispatcher *dispatcher = CameraManager::instance()->eventDispatcher();
 		std::string data("H2G2");
 		Timer timeout;
+		ssize_t ret;
 
 		EventNotifier readNotifier(pipefd_[0], EventNotifier::Read);
 		readNotifier.activated.connect(this, &EventTest::readReady);
@@ -46,7 +47,11 @@ protected:
 		memset(data_, 0, sizeof(data_));
 		size_ = 0;
 
-		write(pipefd_[1], data.data(), data.size());
+		ret = write(pipefd_[1], data.data(), data.size());
+		if (ret < 0) {
+			cout << "Pipe write failed" << endl;
+			return TestFail;
+		}
 
 		timeout.start(100);
 		dispatcher->processEvents();
@@ -73,7 +78,11 @@ protected:
 		notified_ = false;
 		readNotifier.setEnabled(false);
 
-		write(pipefd_[1], data.data(), data.size());
+		ret = write(pipefd_[1], data.data(), data.size());
+		if (ret < 0) {
+			cout << "Pipe write failed" << endl;
+			return TestFail;
+		}
 
 		timeout.start(100);
 		dispatcher->processEvents();