v4l2: V4L2CameraProxy: Take V4L2CameraFile as argument for intercepted calls

Prepare for using the V4L2CameraFile as a container for file-specific
information in the V4L2 compatibility layer by making it a required
argument for all V4L2CameraProxy calls that are directed from
V4L2CompatManager, which are intercepted via LD_PRELOAD. Change
V4L2CameraFile accordingly.

Also change V4L2CompatManager accordingly. Instead of keeping a map of
file descriptors to V4L2CameraProxy instances, we keep a map of
V4L2CameraFile instances to V4L2CameraProxy instances. When the
proxy methods are called, feed the file as a parameter.

The dup function is also modified, in that it is removed from
V4L2CameraProxy, and is handled completely in V4L2CompatManager, as a
map from file descriptors to V4L2CameraFile instances.

Signed-off-by: Paul Elder <paul.elder@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

5 files changed, 88 insertions, 106 deletions

diff --git a/src/v4l2/v4l2_camera_file.cpp b/src/v4l2/v4l2_camera_file.cpp
index d3232ab2..a07679b5 100644
--- a/src/v4l2/v4l2_camera_file.cpp
+++ b/src/v4l2/v4l2_camera_file.cpp
@@ -17,10 +17,10 @@ V4L2CameraFile::V4L2CameraFile(int efd, bool nonBlocking, V4L2CameraProxy *proxy
 	: proxy_(proxy), nonBlocking_(nonBlocking), efd_(efd),
 	  priority_(V4L2_PRIORITY_DEFAULT)
 {
-	proxy_->open(nonBlocking);
+	proxy_->open(this);
 }
 
 V4L2CameraFile::~V4L2CameraFile()
 {
-	proxy_->close();
+	proxy_->close(this);
 }
diff --git a/src/v4l2/v4l2_camera_proxy.cpp b/src/v4l2/v4l2_camera_proxy.cpp
index 86b87e37..301f1c08 100644
--- a/src/v4l2/v4l2_camera_proxy.cpp
+++ b/src/v4l2/v4l2_camera_proxy.cpp
@@ -23,6 +23,7 @@
 #include "libcamera/internal/utils.h"
 
 #include "v4l2_camera.h"
+#include "v4l2_camera_file.h"
 #include "v4l2_compat_manager.h"
 
 #define KERNEL_VERSION(a, b, c) (((a) << 16) + ((b) << 8) + (c))
@@ -39,9 +40,9 @@ V4L2CameraProxy::V4L2CameraProxy(unsigned int index,
 	querycap(camera);
 }
 
-int V4L2CameraProxy::open(bool nonBlocking)
+int V4L2CameraProxy::open(V4L2CameraFile *file)
 {
-	LOG(V4L2Compat, Debug) << "Servicing open";
+	LOG(V4L2Compat, Debug) << "Servicing open fd = " << file->efd();
 
 	int ret = vcam_->open();
 	if (ret < 0) {
@@ -49,8 +50,6 @@ int V4L2CameraProxy::open(bool nonBlocking)
 		return -1;
 	}
 
-	nonBlocking_ = nonBlocking;
-
 	vcam_->getStreamConfig(&streamConfig_);
 	setFmtFromConfig(streamConfig_);
 	sizeimage_ = calculateSizeImage(streamConfig_);
@@ -60,14 +59,10 @@ int V4L2CameraProxy::open(bool nonBlocking)
 	return 0;
 }
 
-void V4L2CameraProxy::dup()
+void V4L2CameraProxy::close(V4L2CameraFile *file)
 {
-	refcount_++;
-}
+	LOG(V4L2Compat, Debug) << "Servicing close fd = " << file->efd();
 
-void V4L2CameraProxy::close()
-{
-	LOG(V4L2Compat, Debug) << "Servicing close";
 
 	if (--refcount_ > 0)
 		return;
@@ -221,9 +216,9 @@ int V4L2CameraProxy::vidioc_querycap(struct v4l2_capability *arg)
 	return 0;
 }
 
-int V4L2CameraProxy::vidioc_enum_fmt(struct v4l2_fmtdesc *arg)
+int V4L2CameraProxy::vidioc_enum_fmt(V4L2CameraFile *file, struct v4l2_fmtdesc *arg)
 {
-	LOG(V4L2Compat, Debug) << "Servicing vidioc_enum_fmt";
+	LOG(V4L2Compat, Debug) << "Servicing vidioc_enum_fmt fd = " << file->efd();
 
 	if (!validateBufferType(arg->type) ||
 	    arg->index >= streamConfig_.formats().pixelformats().size())
@@ -237,9 +232,9 @@ int V4L2CameraProxy::vidioc_enum_fmt(struct v4l2_fmtdesc *arg)
 	return 0;
 }
 
-int V4L2CameraProxy::vidioc_g_fmt(struct v4l2_format *arg)
+int V4L2CameraProxy::vidioc_g_fmt(V4L2CameraFile *file, struct v4l2_format *arg)
 {
-	LOG(V4L2Compat, Debug) << "Servicing vidioc_g_fmt";
+	LOG(V4L2Compat, Debug) << "Servicing vidioc_g_fmt fd = " << file->efd();
 
 	if (!validateBufferType(arg->type))
 		return -EINVAL;
@@ -275,9 +270,9 @@ void V4L2CameraProxy::tryFormat(struct v4l2_format *arg)
 	arg->fmt.pix.colorspace   = V4L2_COLORSPACE_SRGB;
 }
 
-int V4L2CameraProxy::vidioc_s_fmt(struct v4l2_format *arg)
+int V4L2CameraProxy::vidioc_s_fmt(V4L2CameraFile *file, struct v4l2_format *arg)
 {
-	LOG(V4L2Compat, Debug) << "Servicing vidioc_s_fmt";
+	LOG(V4L2Compat, Debug) << "Servicing vidioc_s_fmt fd = " << file->efd();
 
 	if (!validateBufferType(arg->type))
 		return -EINVAL;
@@ -302,9 +297,9 @@ int V4L2CameraProxy::vidioc_s_fmt(struct v4l2_format *arg)
 	return 0;
 }
 
-int V4L2CameraProxy::vidioc_try_fmt(struct v4l2_format *arg)
+int V4L2CameraProxy::vidioc_try_fmt(V4L2CameraFile *file, struct v4l2_format *arg)
 {
-	LOG(V4L2Compat, Debug) << "Servicing vidioc_try_fmt";
+	LOG(V4L2Compat, Debug) << "Servicing vidioc_try_fmt fd = " << file->efd();
 
 	if (!validateBufferType(arg->type))
 		return -EINVAL;
@@ -329,11 +324,9 @@ int V4L2CameraProxy::freeBuffers()
 	return 0;
 }
 
-int V4L2CameraProxy::vidioc_reqbufs(struct v4l2_requestbuffers *arg)
+int V4L2CameraProxy::vidioc_reqbufs(V4L2CameraFile *file, struct v4l2_requestbuffers *arg)
 {
-	int ret;
-
-	LOG(V4L2Compat, Debug) << "Servicing vidioc_reqbufs";
+	LOG(V4L2Compat, Debug) << "Servicing vidioc_reqbufs fd = " << file->efd();
 
 	if (!validateBufferType(arg->type) ||
 	    !validateMemoryType(arg->memory))
@@ -347,9 +340,9 @@ int V4L2CameraProxy::vidioc_reqbufs(struct v4l2_requestbuffers *arg)
 		return freeBuffers();
 
 	Size size(curV4L2Format_.fmt.pix.width, curV4L2Format_.fmt.pix.height);
-	ret = vcam_->configure(&streamConfig_, size,
-			       v4l2ToDrm(curV4L2Format_.fmt.pix.pixelformat),
-			       arg->count);
+	int ret = vcam_->configure(&streamConfig_, size,
+				   v4l2ToDrm(curV4L2Format_.fmt.pix.pixelformat),
+				   arg->count);
 	if (ret < 0)
 		return -EINVAL;
 
@@ -396,9 +389,9 @@ int V4L2CameraProxy::vidioc_reqbufs(struct v4l2_requestbuffers *arg)
 	return 0;
 }
 
-int V4L2CameraProxy::vidioc_querybuf(struct v4l2_buffer *arg)
+int V4L2CameraProxy::vidioc_querybuf(V4L2CameraFile *file, struct v4l2_buffer *arg)
 {
-	LOG(V4L2Compat, Debug) << "Servicing vidioc_querybuf";
+	LOG(V4L2Compat, Debug) << "Servicing vidioc_querybuf fd = " << file->efd();
 
 	if (!validateBufferType(arg->type) ||
 	    arg->index >= bufferCount_)
@@ -411,10 +404,10 @@ int V4L2CameraProxy::vidioc_querybuf(struct v4l2_buffer *arg)
 	return 0;
 }
 
-int V4L2CameraProxy::vidioc_qbuf(struct v4l2_buffer *arg)
+int V4L2CameraProxy::vidioc_qbuf(V4L2CameraFile *file, struct v4l2_buffer *arg)
 {
 	LOG(V4L2Compat, Debug) << "Servicing vidioc_qbuf, index = "
-			       << arg->index;
+			       << arg->index << " fd = " << file->efd();
 
 	if (!validateBufferType(arg->type) ||
 	    !validateMemoryType(arg->memory) ||
@@ -431,15 +424,15 @@ int V4L2CameraProxy::vidioc_qbuf(struct v4l2_buffer *arg)
 	return ret;
 }
 
-int V4L2CameraProxy::vidioc_dqbuf(struct v4l2_buffer *arg)
+int V4L2CameraProxy::vidioc_dqbuf(V4L2CameraFile *file, struct v4l2_buffer *arg)
 {
-	LOG(V4L2Compat, Debug) << "Servicing vidioc_dqbuf";
+	LOG(V4L2Compat, Debug) << "Servicing vidioc_dqbuf fd = " << file->efd();
 
 	if (!validateBufferType(arg->type) ||
 	    !validateMemoryType(arg->memory))
 		return -EINVAL;
 
-	if (!nonBlocking_)
+	if (!file->nonBlocking())
 		vcam_->bufferSema_.acquire();
 	else if (!vcam_->bufferSema_.tryAcquire())
 		return -EAGAIN;
@@ -455,16 +448,16 @@ int V4L2CameraProxy::vidioc_dqbuf(struct v4l2_buffer *arg)
 	currentBuf_ = (currentBuf_ + 1) % bufferCount_;
 
 	uint64_t data;
-	int ret = ::read(efd_, &data, sizeof(data));
+	int ret = ::read(file->efd(), &data, sizeof(data));
 	if (ret != sizeof(data))
 		LOG(V4L2Compat, Error) << "Failed to clear eventfd POLLIN";
 
 	return 0;
 }
 
-int V4L2CameraProxy::vidioc_streamon(int *arg)
+int V4L2CameraProxy::vidioc_streamon(V4L2CameraFile *file, int *arg)
 {
-	LOG(V4L2Compat, Debug) << "Servicing vidioc_streamon";
+	LOG(V4L2Compat, Debug) << "Servicing vidioc_streamon fd = " << file->efd();
 
 	if (!validateBufferType(*arg))
 		return -EINVAL;
@@ -474,9 +467,9 @@ int V4L2CameraProxy::vidioc_streamon(int *arg)
 	return vcam_->streamOn();
 }
 
-int V4L2CameraProxy::vidioc_streamoff(int *arg)
+int V4L2CameraProxy::vidioc_streamoff(V4L2CameraFile *file, int *arg)
 {
-	LOG(V4L2Compat, Debug) << "Servicing vidioc_streamoff";
+	LOG(V4L2Compat, Debug) << "Servicing vidioc_streamoff fd = " << file->efd();
 
 	if (!validateBufferType(*arg))
 		return -EINVAL;
@@ -489,7 +482,7 @@ int V4L2CameraProxy::vidioc_streamoff(int *arg)
 	return ret;
 }
 
-int V4L2CameraProxy::ioctl(unsigned long request, void *arg)
+int V4L2CameraProxy::ioctl(V4L2CameraFile *file, unsigned long request, void *arg)
 {
 	int ret;
 	switch (request) {
@@ -497,34 +490,34 @@ int V4L2CameraProxy::ioctl(unsigned long request, void *arg)
 		ret = vidioc_querycap(static_cast<struct v4l2_capability *>(arg));
 		break;
 	case VIDIOC_ENUM_FMT:
-		ret = vidioc_enum_fmt(static_cast<struct v4l2_fmtdesc *>(arg));
+		ret = vidioc_enum_fmt(file, static_cast<struct v4l2_fmtdesc *>(arg));
 		break;
 	case VIDIOC_G_FMT:
-		ret = vidioc_g_fmt(static_cast<struct v4l2_format *>(arg));
+		ret = vidioc_g_fmt(file, static_cast<struct v4l2_format *>(arg));
 		break;
 	case VIDIOC_S_FMT:
-		ret = vidioc_s_fmt(static_cast<struct v4l2_format *>(arg));
+		ret = vidioc_s_fmt(file, static_cast<struct v4l2_format *>(arg));
 		break;
 	case VIDIOC_TRY_FMT:
-		ret = vidioc_try_fmt(static_cast<struct v4l2_format *>(arg));
+		ret = vidioc_try_fmt(file, static_cast<struct v4l2_format *>(arg));
 		break;
 	case VIDIOC_REQBUFS:
-		ret = vidioc_reqbufs(static_cast<struct v4l2_requestbuffers *>(arg));
+		ret = vidioc_reqbufs(file, static_cast<struct v4l2_requestbuffers *>(arg));
 		break;
 	case VIDIOC_QUERYBUF:
-		ret = vidioc_querybuf(static_cast<struct v4l2_buffer *>(arg));
+		ret = vidioc_querybuf(file, static_cast<struct v4l2_buffer *>(arg));
 		break;
 	case VIDIOC_QBUF:
-		ret = vidioc_qbuf(static_cast<struct v4l2_buffer *>(arg));
+		ret = vidioc_qbuf(file, static_cast<struct v4l2_buffer *>(arg));
 		break;
 	case VIDIOC_DQBUF:
-		ret = vidioc_dqbuf(static_cast<struct v4l2_buffer *>(arg));
+		ret = vidioc_dqbuf(file, static_cast<struct v4l2_buffer *>(arg));
 		break;
 	case VIDIOC_STREAMON:
-		ret = vidioc_streamon(static_cast<int *>(arg));
+		ret = vidioc_streamon(file, static_cast<int *>(arg));
 		break;
 	case VIDIOC_STREAMOFF:
-		ret = vidioc_streamoff(static_cast<int *>(arg));
+		ret = vidioc_streamoff(file, static_cast<int *>(arg));
 		break;
 	default:
 		ret = -ENOTTY;
diff --git a/src/v4l2/v4l2_camera_proxy.h b/src/v4l2/v4l2_camera_proxy.h
index 27d3e507..b2197ef8 100644
--- a/src/v4l2/v4l2_camera_proxy.h
+++ b/src/v4l2/v4l2_camera_proxy.h
@@ -21,20 +21,20 @@
 
 using namespace libcamera;
 
+class V4L2CameraFile;
+
 class V4L2CameraProxy
 {
 public:
 	V4L2CameraProxy(unsigned int index, std::shared_ptr<Camera> camera);
 
-	int open(bool nonBlocking);
-	void dup();
-	void close();
+	int open(V4L2CameraFile *file);
+	void close(V4L2CameraFile *file);
 	void *mmap(void *addr, size_t length, int prot, int flags, off64_t offset);
 	int munmap(void *addr, size_t length);
 
-	int ioctl(unsigned long request, void *arg);
-
 	void bind(int fd);
+	int ioctl(V4L2CameraFile *file, unsigned long request, void *arg);
 
 private:
 	bool validateBufferType(uint32_t type);
@@ -47,16 +47,16 @@ private:
 	int freeBuffers();
 
 	int vidioc_querycap(struct v4l2_capability *arg);
-	int vidioc_enum_fmt(struct v4l2_fmtdesc *arg);
-	int vidioc_g_fmt(struct v4l2_format *arg);
-	int vidioc_s_fmt(struct v4l2_format *arg);
-	int vidioc_try_fmt(struct v4l2_format *arg);
-	int vidioc_reqbufs(struct v4l2_requestbuffers *arg);
-	int vidioc_querybuf(struct v4l2_buffer *arg);
-	int vidioc_qbuf(struct v4l2_buffer *arg);
-	int vidioc_dqbuf(struct v4l2_buffer *arg);
-	int vidioc_streamon(int *arg);
-	int vidioc_streamoff(int *arg);
+	int vidioc_enum_fmt(V4L2CameraFile *file, struct v4l2_fmtdesc *arg);
+	int vidioc_g_fmt(V4L2CameraFile *file, struct v4l2_format *arg);
+	int vidioc_s_fmt(V4L2CameraFile *file, struct v4l2_format *arg);
+	int vidioc_try_fmt(V4L2CameraFile *file, struct v4l2_format *arg);
+	int vidioc_reqbufs(V4L2CameraFile *file, struct v4l2_requestbuffers *arg);
+	int vidioc_querybuf(V4L2CameraFile *file, struct v4l2_buffer *arg);
+	int vidioc_qbuf(V4L2CameraFile *file, struct v4l2_buffer *arg);
+	int vidioc_dqbuf(V4L2CameraFile *file, struct v4l2_buffer *arg);
+	int vidioc_streamon(V4L2CameraFile *file, int *arg);
+	int vidioc_streamoff(V4L2CameraFile *file, int *arg);
 
 	static unsigned int bplMultiplier(uint32_t format);
 	static unsigned int imageSize(uint32_t format, unsigned int width,
@@ -67,7 +67,6 @@ private:
 
 	unsigned int refcount_;
 	unsigned int index_;
-	bool nonBlocking_;
 
 	struct v4l2_format curV4L2Format_;
 	StreamConfiguration streamConfig_;
diff --git a/src/v4l2/v4l2_compat_manager.cpp b/src/v4l2/v4l2_compat_manager.cpp
index 8da33164..90c0f012 100644
--- a/src/v4l2/v4l2_compat_manager.cpp
+++ b/src/v4l2/v4l2_compat_manager.cpp
@@ -24,6 +24,8 @@
 
 #include "libcamera/internal/log.h"
 
+#include "v4l2_camera_file.h"
+
 using namespace libcamera;
 
 LOG_DEFINE_CATEGORY(V4L2Compat)
@@ -49,7 +51,7 @@ V4L2CompatManager::V4L2CompatManager()
 
 V4L2CompatManager::~V4L2CompatManager()
 {
-	devices_.clear();
+	files_.clear();
 	mmaps_.clear();
 
 	if (cm_) {
@@ -95,13 +97,13 @@ V4L2CompatManager *V4L2CompatManager::instance()
 	return &instance;
 }
 
-V4L2CameraProxy *V4L2CompatManager::getProxy(int fd)
+std::shared_ptr<V4L2CameraFile> V4L2CompatManager::cameraFile(int fd)
 {
-	auto device = devices_.find(fd);
-	if (device == devices_.end())
+	auto file = files_.find(fd);
+	if (file == files_.end())
 		return nullptr;
 
-	return device->second;
+	return file->second;
 }
 
 int V4L2CompatManager::getCameraIndex(int fd)
@@ -148,25 +150,14 @@ int V4L2CompatManager::openat(int dirfd, const char *path, int oflag, mode_t mod
 
 	fops_.close(fd);
 
-	unsigned int camera_index = static_cast<unsigned int>(ret);
-
-	V4L2CameraProxy *proxy = proxies_[camera_index].get();
-	ret = proxy->open(oflag & O_NONBLOCK);
-	if (ret < 0)
-		return ret;
-
 	int efd = eventfd(0, EFD_SEMAPHORE |
 			     ((oflag & O_CLOEXEC) ? EFD_CLOEXEC : 0) |
 			     ((oflag & O_NONBLOCK) ? EFD_NONBLOCK : 0));
-	if (efd < 0) {
-		int err = errno;
-		proxy->close();
-		errno = err;
+	if (efd < 0)
 		return efd;
-	}
 
-	proxy->bind(efd);
-	devices_.emplace(efd, proxy);
+	V4L2CameraProxy *proxy = proxies_[ret].get();
+	files_.emplace(efd, std::make_shared<V4L2CameraFile>(efd, oflag & O_NONBLOCK, proxy));
 
 	return efd;
 }
@@ -177,40 +168,39 @@ int V4L2CompatManager::dup(int oldfd)
 	if (newfd < 0)
 		return newfd;
 
-	auto device = devices_.find(oldfd);
-	if (device != devices_.end()) {
-		V4L2CameraProxy *proxy = device->second;
-		devices_[newfd] = proxy;
-		proxy->dup();
-	}
+	auto file = files_.find(oldfd);
+	if (file != files_.end())
+		files_[newfd] = file->second;
 
 	return newfd;
 }
 
 int V4L2CompatManager::close(int fd)
 {
-	V4L2CameraProxy *proxy = getProxy(fd);
-	if (proxy) {
-		proxy->close();
-		devices_.erase(fd);
-		return 0;
-	}
+	auto file = files_.find(fd);
+	if (file != files_.end())
+		files_.erase(file);
 
+	/* We still need to close the eventfd. */
 	return fops_.close(fd);
 }
 
 void *V4L2CompatManager::mmap(void *addr, size_t length, int prot, int flags,
 			      int fd, off64_t offset)
 {
-	V4L2CameraProxy *proxy = getProxy(fd);
-	if (!proxy)
+	std::shared_ptr<V4L2CameraFile> file = cameraFile(fd);
+	if (!file)
 		return fops_.mmap(addr, length, prot, flags, fd, offset);
 
-	void *map = proxy->mmap(addr, length, prot, flags, offset);
+	void *map = file->proxy()->mmap(addr, length, prot, flags, offset);
 	if (map == MAP_FAILED)
 		return map;
 
-	mmaps_[map] = proxy;
+	/*
+	 * Map to V4L2CameraProxy directly to prevent adding more references
+	 * to V4L2CameraFile.
+	 */
+	mmaps_[map] = file->proxy();
 	return map;
 }
 
@@ -233,9 +223,9 @@ int V4L2CompatManager::munmap(void *addr, size_t length)
 
 int V4L2CompatManager::ioctl(int fd, unsigned long request, void *arg)
 {
-	V4L2CameraProxy *proxy = getProxy(fd);
-	if (!proxy)
+	std::shared_ptr<V4L2CameraFile> file = cameraFile(fd);
+	if (!file)
 		return fops_.ioctl(fd, request, arg);
 
-	return proxy->ioctl(request, arg);
+	return file->proxy()->ioctl(file.get(), request, arg);
 }
diff --git a/src/v4l2/v4l2_compat_manager.h b/src/v4l2/v4l2_compat_manager.h
index 3d4e512e..bc548ab2 100644
--- a/src/v4l2/v4l2_compat_manager.h
+++ b/src/v4l2/v4l2_compat_manager.h
@@ -44,7 +44,6 @@ public:
 
 	static V4L2CompatManager *instance();
 
-	V4L2CameraProxy *getProxy(int fd);
 	const FileOperations &fops() const { return fops_; }
 
 	int openat(int dirfd, const char *path, int oflag, mode_t mode);
@@ -62,13 +61,14 @@ private:
 
 	int start();
 	int getCameraIndex(int fd);
+	std::shared_ptr<V4L2CameraFile> cameraFile(int fd);
 
 	FileOperations fops_;
 
 	CameraManager *cm_;
 
 	std::vector<std::unique_ptr<V4L2CameraProxy>> proxies_;
-	std::map<int, V4L2CameraProxy *> devices_;
+	std::map<int, std::shared_ptr<V4L2CameraFile>> files_;
 	std::map<void *, V4L2CameraProxy *> mmaps_;
 };