Fix AppFuse JNI. (2153e822) · Commits · e / os / android_frameworks_base

packages/MtpDocumentsProvider/jni/com_android_mtp_AppFuse.cpp

+106 −75

Original line number	Diff line number	Diff line
		@@ -34,27 +34,33 @@

		namespace {

		// Maximum number of bytes to write in one request.
		// The numbers came from sdcard.c.
		// Maximum number of bytes to write/read in one request/one reply.
		constexpr size_t MAX_WRITE = 256 * 1024;
		constexpr size_t MAX_READ = 128 * 1024;

		constexpr size_t NUM_MAX_HANDLES = 1024;

		// Largest possible request.
		// The request size is bounded by the maximum size of a FUSE_WRITE request
		// because it has the largest possible data payload.
		constexpr size_t MAX_REQUEST_SIZE = sizeof(struct fuse_in_header) +
		sizeof(struct fuse_write_in) + MAX_WRITE;
		sizeof(struct fuse_write_in) + std::max(MAX_WRITE, MAX_READ);

		static jclass app_fuse_class;
		static jmethodID app_fuse_get_file_size;
		static jmethodID app_fuse_get_object_bytes;

		// NOTE:
		// FuseRequest and FuseResponse shares the same buffer to save memory usage, so the handlers must
		// not access input buffer after writing data to output buffer.
		struct FuseRequest {
		char buffer[MAX_REQUEST_SIZE];
		FuseRequest() {}
		const struct fuse_in_header& header() const {
		return (const struct fuse_in_header) buffer;
		}
		const void* data() const {
		void* data() {
		return (buffer + sizeof(struct fuse_in_header));
		}
		size_t data_length() const {
		@@ -62,6 +68,26 @@ struct FuseRequest {
		}
		};

		template<typename T>
		class FuseResponse {
		size_t size_;
		T* const buffer_;
		public:
		FuseResponse(void* buffer) : size_(0), buffer_(static_cast<T*>(buffer)) {}

		void prepare_buffer(size_t size = sizeof(T)) {
		memset(buffer_, 0, size);
		size_ = size;
		}

		void set_size(size_t size) {
		size_ = size;
		}

		size_t size() const { return size_; }
		T* data() const { return buffer_; }
		};

		class ScopedFd {
		int mFd;

		@@ -76,7 +102,7 @@ public:
		};

		/**
		* The class is used to access AppFuse class in Java from fuse handlers.
		* Fuse implementation consists of handlers parsing FUSE commands.
		*/
		class AppFuse {
		JNIEnv* env_;
		@@ -90,9 +116,9 @@ public:
		AppFuse(JNIEnv* env, jobject self) :
		env_(env), self_(self), handle_counter_(0) {}

		bool handle_fuse_request(int fd, const FuseRequest& req) {
		ALOGV("Request op=%d", req.header().opcode);
		switch (req.header().opcode) {
		bool handle_fuse_request(int fd, FuseRequest* req) {
		ALOGV("Request op=%d", req->header().opcode);
		switch (req->header().opcode) {
		// TODO: Handle more operations that are enough to provide seekable
		// FD.
		case FUSE_LOOKUP:
		@@ -110,20 +136,20 @@ public:
		invoke_handler(fd, req, &AppFuse::handle_fuse_open);
		return true;
		case FUSE_READ:
		invoke_handler(fd, req, &AppFuse::handle_fuse_read, 8192);
		invoke_handler(fd, req, &AppFuse::handle_fuse_read);
		return true;
		case FUSE_RELEASE:
		invoke_handler(fd, req, &AppFuse::handle_fuse_release, 0);
		invoke_handler(fd, req, &AppFuse::handle_fuse_release);
		return true;
		case FUSE_FLUSH:
		invoke_handler(fd, req, &AppFuse::handle_fuse_flush, 0);
		invoke_handler(fd, req, &AppFuse::handle_fuse_flush);
		return true;
		default: {
		ALOGV("NOTIMPL op=%d uniq=%" PRIx64 " nid=%" PRIx64 "\n",
		req.header().opcode,
		req.header().unique,
		req.header().nodeid);
		fuse_reply(fd, req.header().unique, -ENOSYS, NULL, 0);
		req->header().opcode,
		req->header().unique,
		req->header().nodeid);
		fuse_reply(fd, req->header().unique, -ENOSYS, NULL, 0);
		return true;
		}
		}
		@@ -132,8 +158,7 @@ public:
		private:
		int handle_fuse_lookup(const fuse_in_header& header,
		const char* name,
		fuse_entry_out* out,
		uint32_t* /unused/) {
		FuseResponse<fuse_entry_out>* out) {
		if (header.nodeid != 1) {
		return -ENOENT;
		}
		@@ -148,19 +173,19 @@ private:
		return -ENOENT;
		}

		out->nodeid = n;
		out->attr_valid = 10;
		out->entry_valid = 10;
		out->attr.ino = n;
		out->attr.mode = S_IFREG \| 0777;
		out->attr.size = size;
		out->prepare_buffer();
		out->data()->nodeid = n;
		out->data()->attr_valid = 10;
		out->data()->entry_valid = 10;
		out->data()->attr.ino = n;
		out->data()->attr.mode = S_IFREG \| 0777;
		out->data()->attr.size = size;
		return 0;
		}

		int handle_fuse_init(const fuse_in_header&,
		const fuse_init_in* in,
		fuse_init_out* out,
		uint32_t* reply_size) {
		FuseResponse<fuse_init_out>* out) {
		// Kernel 2.6.16 is the first stable kernel with struct fuse_init_out
		// defined (fuse version 7.6). The structure is the same from 7.6 through
		// 7.22. Beginning with 7.23, the structure increased in size and added
		@@ -172,50 +197,58 @@ private:
		return -1;
		}

		// Before writing \|out\|, we need to copy data from \|in\|.
		const uint32_t minor = in->minor;
		const uint32_t max_readahead = in->max_readahead;

		// We limit ourselves to 15 because we don't handle BATCH_FORGET yet
		out->minor = std::min(in->minor, 15u);
		size_t response_size = sizeof(fuse_init_out);
		#if defined(FUSE_COMPAT_22_INIT_OUT_SIZE)
		// FUSE_KERNEL_VERSION >= 23.

		// If the kernel only works on minor revs older than or equal to 22,
		// then use the older structure size since this code only uses the 7.22
		// version of the structure.
		if (in->minor <= 22) {
		*reply_size = FUSE_COMPAT_22_INIT_OUT_SIZE;
		if (minor <= 22) {
		response_size = FUSE_COMPAT_22_INIT_OUT_SIZE;
		}
		#else
		// Don't drop this line to prevent an 'unused' compile error.
		*reply_size = sizeof(fuse_init_out);
		#endif

		out->major = FUSE_KERNEL_VERSION;
		out->max_readahead = in->max_readahead;
		out->flags = FUSE_ATOMIC_O_TRUNC \| FUSE_BIG_WRITES;
		out->max_background = 32;
		out->congestion_threshold = 32;
		out->max_write = MAX_WRITE;
		out->prepare_buffer(response_size);
		out->data()->major = FUSE_KERNEL_VERSION;
		out->data()->minor = std::min(minor, 15u);
		out->data()->max_readahead = max_readahead;
		out->data()->flags = FUSE_ATOMIC_O_TRUNC \| FUSE_BIG_WRITES;
		out->data()->max_background = 32;
		out->data()->congestion_threshold = 32;
		out->data()->max_write = MAX_WRITE;

		return 0;
		}

		int handle_fuse_getattr(const fuse_in_header& header,
		const fuse_getattr_in* /* in */,
		fuse_attr_out* out,
		uint32_t* /unused/) {
		if (header.nodeid != 1) {
		FuseResponse<fuse_attr_out>* out) {
		out->prepare_buffer();
		out->data()->attr_valid = 10;
		out->data()->attr.ino = header.nodeid;
		if (header.nodeid == 1) {
		out->data()->attr.mode = S_IFDIR \| 0777;
		out->data()->attr.size = 0;
		} else {
		int64_t size = get_file_size(header.nodeid);
		if (size < 0) {
		return -ENOENT;
		}
		out->attr_valid = 1000 * 60 * 10;
		out->attr.ino = header.nodeid;
		out->attr.mode = S_IFDIR \| 0777;
		out->attr.size = 0;
		out->data()->attr.mode = S_IFREG \| 0777;
		out->data()->attr.size = size;
		}

		return 0;
		}

		int handle_fuse_open(const fuse_in_header& header,
		const fuse_open_in* /* in */,
		fuse_open_out* out,
		uint32_t* /unused/) {
		FuseResponse<fuse_open_out>* out) {
		if (handles_.size() >= NUM_MAX_HANDLES) {
		// Too many open files.
		return -EMFILE;
		@@ -224,68 +257,66 @@ private:
		do {
		handle = handle_counter_++;
		} while (handles_.count(handle) != 0);

		handles_.insert(std::make_pair(handle, header.nodeid));
		out->fh = handle;

		out->prepare_buffer();
		out->data()->fh = handle;
		return 0;
		}

		int handle_fuse_read(const fuse_in_header& /* header */,
		const fuse_read_in* in,
		void* out,
		uint32_t* reply_size) {
		FuseResponse<void>* out) {
		if (in->size > MAX_READ) {
		return -EINVAL;
		}
		const std::map<uint32_t, uint64_t>::iterator it = handles_.find(in->fh);
		if (it == handles_.end()) {
		return -EBADF;
		}
		const int64_t result = get_object_bytes(
		it->second,
		in->offset,
		in->size,
		out);
		uint64_t offset = in->offset;
		uint32_t size = in->size;

		// Overwrite the size after writing data.
		out->prepare_buffer(0);
		const int64_t result = get_object_bytes(it->second, offset, size, out->data());
		if (result < 0) {
		return -EIO;
		}
		*reply_size = static_cast<size_t>(result);
		out->set_size(result);
		return 0;
		}

		int handle_fuse_release(const fuse_in_header& /* header */,
		const fuse_release_in* in,
		void* /* out */,
		uint32_t* /* reply_size */) {
		FuseResponse<void>* /* out */) {
		handles_.erase(in->fh);
		return 0;
		}

		int handle_fuse_flush(const fuse_in_header& /* header */,
		const void* /* in */,
		void* /* out */,
		uint32_t* /* reply_size */) {
		FuseResponse<void>* /* out */) {
		return 0;
		}

		template <typename T, typename S>
		void invoke_handler(int fd,
		const FuseRequest& request,
		FuseRequest* request,
		int (AppFuse::*handler)(const fuse_in_header&,
		const T*,
		S*,
		uint32_t*),
		uint32_t reply_size = sizeof(S)) {
		char reply_data[reply_size];
		memset(reply_data, 0, reply_size);
		FuseResponse<S>*)) {
		FuseResponse<S> response(request->data());
		const int reply_code = (this->*handler)(
		request.header(),
		static_cast<const T*>(request.data()),
		reinterpret_cast<S*>(reply_data),
		&reply_size);
		request->header(),
		static_cast<const T*>(request->data()),
		&response);
		fuse_reply(
		fd,
		request.header().unique,
		request->header().unique,
		reply_code,
		reply_data,
		reply_size);
		request->data(),
		response.size());
		}

		int64_t get_file_size(int inode) {
		@@ -378,7 +409,7 @@ jboolean com_android_mtp_AppFuse_start_app_fuse_loop(
		continue;
		}

		if (!appfuse.handle_fuse_request(fd, request)) {
		if (!appfuse.handle_fuse_request(fd, &request)) {
		return JNI_TRUE;
		}
		}