1 files changed, 338 insertions, 0 deletions
diff --git a/mtp/ffs/MtpFfsCompatHandle.cpp b/mtp/ffs/MtpFfsCompatHandle.cpp
new file mode 100644
index 000000000..4027d601c
--- /dev/null
+++ b/mtp/ffs/MtpFfsCompatHandle.cpp
@@ -0,0 +1,338 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *		http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <android-base/logging.h>
+#include <android-base/properties.h>
+#include <dirent.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <linux/usb/ch9.h>
+#include <linux/usb/functionfs.h>
+#include <mutex>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/endian.h>
+#include <sys/ioctl.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include "PosixAsyncIO.h"
+#include "MtpFfsCompatHandle.h"
+#include "mtp.h"
+
+#define FUNCTIONFS_ENDPOINT_ALLOC		_IOR('g', 231, __u32)
+
+namespace {
+
+// Must be divisible by all max packet size values
+constexpr int MAX_FILE_CHUNK_SIZE = 3145728;
+
+// Safe values since some devices cannot handle large DMAs
+// To get good performance, override these with
+// higher values per device using the properties
+// sys.usb.ffs.max_read and sys.usb.ffs.max_write
+constexpr int USB_FFS_MAX_WRITE = MTP_BUFFER_SIZE;
+constexpr int USB_FFS_MAX_READ = MTP_BUFFER_SIZE;
+
+static_assert(USB_FFS_MAX_WRITE > 0, "Max r/w values must be > 0!");
+static_assert(USB_FFS_MAX_READ > 0, "Max r/w values must be > 0!");
+
+constexpr unsigned int MAX_MTP_FILE_SIZE = 0xFFFFFFFF;
+
+constexpr size_t ENDPOINT_ALLOC_RETRIES = 10;
+
+} // anonymous namespace
+
+
+MtpFfsCompatHandle::MtpFfsCompatHandle(int controlFd) :
+	MtpFfsHandle(controlFd),
+	mMaxWrite(USB_FFS_MAX_WRITE),
+	mMaxRead(USB_FFS_MAX_READ) {}
+
+MtpFfsCompatHandle::~MtpFfsCompatHandle() {}
+
+int MtpFfsCompatHandle::writeHandle(int fd, const void* data, size_t len) {
+	int ret = 0;
+	const char* buf = static_cast<const char*>(data);
+	while (len > 0) {
+		int write_len = std::min(mMaxWrite, len);
+		int n = TEMP_FAILURE_RETRY(::write(fd, buf, write_len));
+
+		if (n < 0) {
+			PLOG(ERROR) << "write ERROR: fd = " << fd << ", n = " << n;
+			return -1;
+		} else if (n < write_len) {
+			errno = EIO;
+			PLOG(ERROR) << "less written than expected";
+			return -1;
+		}
+		buf += n;
+		len -= n;
+		ret += n;
+	}
+	return ret;
+}
+
+int MtpFfsCompatHandle::readHandle(int fd, void* data, size_t len) {
+	int ret = 0;
+	char* buf = static_cast<char*>(data);
+	while (len > 0) {
+		int read_len = std::min(mMaxRead, len);
+		int n = TEMP_FAILURE_RETRY(::read(fd, buf, read_len));
+		if (n < 0) {
+			PLOG(ERROR) << "read ERROR: fd = " << fd << ", n = " << n;
+			return -1;
+		}
+		ret += n;
+		if (n < read_len) // done reading early
+			break;
+		buf += n;
+		len -= n;
+	}
+	return ret;
+}
+
+int MtpFfsCompatHandle::start(bool ptp) {
+	if (!openEndpoints(ptp))
+		return -1;
+
+	for (unsigned i = 0; i < NUM_IO_BUFS; i++) {
+		mIobuf[i].bufs.resize(MAX_FILE_CHUNK_SIZE);
+		posix_madvise(mIobuf[i].bufs.data(), MAX_FILE_CHUNK_SIZE,
+				POSIX_MADV_SEQUENTIAL | POSIX_MADV_WILLNEED);
+	}
+
+	// Get device specific r/w size
+	mMaxWrite = android::base::GetIntProperty("sys.usb.ffs.max_write", USB_FFS_MAX_WRITE);
+	mMaxRead = android::base::GetIntProperty("sys.usb.ffs.max_read", USB_FFS_MAX_READ);
+
+	size_t attempts = 0;
+	while (mMaxWrite >= USB_FFS_MAX_WRITE && mMaxRead >= USB_FFS_MAX_READ &&
+			attempts < ENDPOINT_ALLOC_RETRIES) {
+		// If larger contiguous chunks of memory aren't available, attempt to try
+		// smaller allocations.
+		if (ioctl(mBulkIn, FUNCTIONFS_ENDPOINT_ALLOC, static_cast<__u32>(mMaxWrite)) ||
+			ioctl(mBulkOut, FUNCTIONFS_ENDPOINT_ALLOC, static_cast<__u32>(mMaxRead))) {
+			if (errno == ENODEV) {
+				// Driver hasn't enabled endpoints yet.
+				std::this_thread::sleep_for(std::chrono::milliseconds(100));
+				attempts += 1;
+				continue;
+			}
+			mMaxWrite /= 2;
+			mMaxRead /=2;
+		} else {
+			return 0;
+		}
+	}
+	// Try to start MtpServer anyway, with the smallest max r/w values
+	mMaxWrite = USB_FFS_MAX_WRITE;
+	mMaxRead = USB_FFS_MAX_READ;
+	PLOG(ERROR) << "Functionfs could not allocate any memory!";
+	return 0;
+}
+
+int MtpFfsCompatHandle::read(void* data, size_t len) {
+	return readHandle(mBulkOut, data, len);
+}
+
+int MtpFfsCompatHandle::write(const void* data, size_t len) {
+	return writeHandle(mBulkIn, data, len);
+}
+
+int MtpFfsCompatHandle::receiveFile(mtp_file_range mfr, bool zero_packet) {
+	// When receiving files, the incoming length is given in 32 bits.
+	// A >4G file is given as 0xFFFFFFFF
+	uint32_t file_length = mfr.length;
+	uint64_t offset = mfr.offset;
+	int packet_size = getPacketSize(mBulkOut);
+
+	unsigned char *data = mIobuf[0].bufs.data();
+	unsigned char *data2 = mIobuf[1].bufs.data();
+
+	struct aiocb aio;
+	aio.aio_fildes = mfr.fd;
+	aio.aio_buf = nullptr;
+	struct aiocb *aiol[] = {&aio};
+	int ret = -1;
+	size_t length;
+	bool read = false;
+	bool write = false;
+
+	posix_fadvise(mfr.fd, 0, 0, POSIX_FADV_SEQUENTIAL | POSIX_FADV_NOREUSE);
+
+	// Break down the file into pieces that fit in buffers
+	while (file_length > 0 || write) {
+		if (file_length > 0) {
+			length = std::min(static_cast<uint32_t>(MAX_FILE_CHUNK_SIZE), file_length);
+
+			// Read data from USB, handle errors after waiting for write thread.
+			ret = readHandle(mBulkOut, data, length);
+
+			if (file_length != MAX_MTP_FILE_SIZE && ret < static_cast<int>(length)) {
+				ret = -1;
+				errno = EIO;
+			}
+			read = true;
+		}
+
+		if (write) {
+			// get the return status of the last write request
+			aio_suspend(aiol, 1, nullptr);
+
+			int written = aio_return(&aio);
+			if (written == -1) {
+				errno = aio_error(&aio);
+				return -1;
+			}
+			if (static_cast<size_t>(written) < aio.aio_nbytes) {
+				errno = EIO;
+				return -1;
+			}
+			write = false;
+		}
+
+		// If there was an error reading above
+		if (ret == -1) {
+			return -1;
+		}
+
+		if (read) {
+			if (file_length == MAX_MTP_FILE_SIZE) {
+				// For larger files, receive until a short packet is received.
+				if (static_cast<size_t>(ret) < length) {
+					file_length = 0;
+				}
+			} else {
+				file_length -= ret;
+			}
+			// Enqueue a new write request
+			aio_prepare(&aio, data, length, offset);
+			aio_write(&aio);
+
+			offset += ret;
+			std::swap(data, data2);
+
+			write = true;
+			read = false;
+		}
+	}
+	// Receive an empty packet if size is a multiple of the endpoint size.
+	if (ret % packet_size == 0 || zero_packet) {
+		if (TEMP_FAILURE_RETRY(::read(mBulkOut, data, packet_size)) != 0) {
+			return -1;
+		}
+	}
+	return 0;
+}
+
+int MtpFfsCompatHandle::sendFile(mtp_file_range mfr) {
+	uint64_t file_length = mfr.length;
+	uint32_t given_length = std::min(static_cast<uint64_t>(MAX_MTP_FILE_SIZE),
+			file_length + sizeof(mtp_data_header));
+	uint64_t offset = mfr.offset;
+	int packet_size = getPacketSize(mBulkIn);
+
+	// If file_length is larger than a size_t, truncating would produce the wrong comparison.
+	// Instead, promote the left side to 64 bits, then truncate the small result.
+	int init_read_len = std::min(
+			static_cast<uint64_t>(packet_size - sizeof(mtp_data_header)), file_length);
+
+	unsigned char *data = mIobuf[0].bufs.data();
+	unsigned char *data2 = mIobuf[1].bufs.data();
+
+	posix_fadvise(mfr.fd, 0, 0, POSIX_FADV_SEQUENTIAL | POSIX_FADV_NOREUSE);
+
+	struct aiocb aio;
+	aio.aio_fildes = mfr.fd;
+	struct aiocb *aiol[] = {&aio};
+	int ret, length;
+	int error = 0;
+	bool read = false;
+	bool write = false;
+
+	// Send the header data
+	mtp_data_header *header = reinterpret_cast<mtp_data_header*>(data);
+	header->length = htole32(given_length);
+	header->type = htole16(2); /* data packet */
+	header->command = htole16(mfr.command);
+	header->transaction_id = htole32(mfr.transaction_id);
+
+	// Some hosts don't support header/data separation even though MTP allows it
+	// Handle by filling first packet with initial file data
+	if (TEMP_FAILURE_RETRY(pread(mfr.fd, reinterpret_cast<char*>(data) +
+					sizeof(mtp_data_header), init_read_len, offset))
+			!= init_read_len) return -1;
+	if (writeHandle(mBulkIn, data, sizeof(mtp_data_header) + init_read_len) == -1) return -1;
+	file_length -= init_read_len;
+	offset += init_read_len;
+	ret = init_read_len + sizeof(mtp_data_header);
+
+	// Break down the file into pieces that fit in buffers
+	while (file_length > 0) {
+		if (read) {
+			// Wait for the previous read to finish
+			aio_suspend(aiol, 1, nullptr);
+			ret = aio_return(&aio);
+			if (ret == -1) {
+				errno = aio_error(&aio);
+				return -1;
+			}
+			if (static_cast<size_t>(ret) < aio.aio_nbytes) {
+				errno = EIO;
+				return -1;
+			}
+
+			file_length -= ret;
+			offset += ret;
+			std::swap(data, data2);
+			read = false;
+			write = true;
+		}
+
+		if (error == -1) {
+			return -1;
+		}
+
+		if (file_length > 0) {
+			length = std::min(static_cast<uint64_t>(MAX_FILE_CHUNK_SIZE), file_length);
+			// Queue up another read
+			aio_prepare(&aio, data, length, offset);
+			aio_read(&aio);
+			read = true;
+		}
+
+		if (write) {
+			if (writeHandle(mBulkIn, data2, ret) == -1) {
+				error = -1;
+			}
+			write = false;
+		}
+	}
+
+	if (ret % packet_size == 0) {
+		// If the last packet wasn't short, send a final empty packet
+		if (TEMP_FAILURE_RETRY(::write(mBulkIn, data, 0)) != 0) {
+			return -1;
+		}
+	}
+
+	return 0;
+}
+