path: root/mtp/ffs/MtpDataPacket.cpp

/*
 * Copyright (C) 2010 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.
 */

#define LOG_TAG "MtpDataPacket"

#include "MtpDataPacket.h"

#include <algorithm>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <sys/types.h>
#include <usbhost/usbhost.h>
#include "MtpStringBuffer.h"
#include "IMtpHandle.h"
#include "MtpDebug.h"

namespace {
// Reads the exact |count| bytes from |fd| to |buf|.
// Returns |count| if it succeed to read the bytes. Otherwise returns -1. If it reaches EOF, the
// function regards it as an error.
ssize_t readExactBytes(int fd, void* buf, size_t count) {
	if (count > SSIZE_MAX) {
		return -1;
	}
	size_t read_count = 0;
	while (read_count < count) {
		int result = read(fd, static_cast<int8_t*>(buf) + read_count, count - read_count);
		// Assume that EOF is error.
		if (result <= 0) {
			return -1;
		}
		read_count += result;
	}
	return read_count == count ? count : -1;
}
}  // namespace

MtpDataPacket::MtpDataPacket()
	:	MtpPacket(MTP_BUFFER_SIZE),   // MAX_USBFS_BUFFER_SIZE
		mOffset(MTP_CONTAINER_HEADER_SIZE)
{
}

MtpDataPacket::~MtpDataPacket() {
}

void MtpDataPacket::reset() {
	MtpPacket::reset();
	mOffset = MTP_CONTAINER_HEADER_SIZE;
}

void MtpDataPacket::setOperationCode(MtpOperationCode code) {
	MtpPacket::putUInt16(MTP_CONTAINER_CODE_OFFSET, code);
}

void MtpDataPacket::setTransactionID(MtpTransactionID id) {
	MtpPacket::putUInt32(MTP_CONTAINER_TRANSACTION_ID_OFFSET, id);
}

bool MtpDataPacket::getUInt8(uint8_t& value) {
	if (mPacketSize - mOffset < sizeof(value))
		return false;
	value = mBuffer[mOffset++];
	return true;
}

bool MtpDataPacket::getUInt16(uint16_t& value) {
	if (mPacketSize - mOffset < sizeof(value))
		return false;
	int offset = mOffset;
	value = (uint16_t)mBuffer[offset] | ((uint16_t)mBuffer[offset + 1] << 8);
	mOffset += sizeof(value);
	return true;
}

bool MtpDataPacket::getUInt32(uint32_t& value) {
	if (mPacketSize - mOffset < sizeof(value))
		return false;
	int offset = mOffset;
	value = (uint32_t)mBuffer[offset] | ((uint32_t)mBuffer[offset + 1] << 8) |
		   ((uint32_t)mBuffer[offset + 2] << 16)  | ((uint32_t)mBuffer[offset + 3] << 24);
	mOffset += sizeof(value);
	return true;
}

bool MtpDataPacket::getUInt64(uint64_t& value) {
	if (mPacketSize - mOffset < sizeof(value))
		return false;
	int offset = mOffset;
	value = (uint64_t)mBuffer[offset] | ((uint64_t)mBuffer[offset + 1] << 8) |
		   ((uint64_t)mBuffer[offset + 2] << 16) | ((uint64_t)mBuffer[offset + 3] << 24) |
		   ((uint64_t)mBuffer[offset + 4] << 32) | ((uint64_t)mBuffer[offset + 5] << 40) |
		   ((uint64_t)mBuffer[offset + 6] << 48)  | ((uint64_t)mBuffer[offset + 7] << 56);
	mOffset += sizeof(value);
	return true;
}

bool MtpDataPacket::getUInt128(uint128_t& value) {
	return getUInt32(value[0]) && getUInt32(value[1]) && getUInt32(value[2]) && getUInt32(value[3]);
}

bool MtpDataPacket::getString(MtpStringBuffer& string)
{
	return string.readFromPacket(this);
}

Int8List* MtpDataPacket::getAInt8() {
	uint32_t count;
	if (!getUInt32(count))
		return NULL;
	Int8List* result = new Int8List;
	for (uint32_t i = 0; i < count; i++) {
		int8_t value;
		if (!getInt8(value)) {
			delete result;
			return NULL;
		}
		result->push_back(value);
	}
	return result;
}

UInt8List* MtpDataPacket::getAUInt8() {
	uint32_t count;
	if (!getUInt32(count))
		return NULL;
	UInt8List* result = new UInt8List;
	for (uint32_t i = 0; i < count; i++) {
		uint8_t value;
		if (!getUInt8(value)) {
			delete result;
			return NULL;
		}
		result->push_back(value);
	}
	return result;
}

Int16List* MtpDataPacket::getAInt16() {
	uint32_t count;
	if (!getUInt32(count))
		return NULL;
	Int16List* result = new Int16List;
	for (uint32_t i = 0; i < count; i++) {
		int16_t value;
		if (!getInt16(value)) {
			delete result;
			return NULL;
		}
		result->push_back(value);
	}
	return result;
}

UInt16List* MtpDataPacket::getAUInt16() {
	uint32_t count;
	if (!getUInt32(count))
		return NULL;
	UInt16List* result = new UInt16List;
	for (uint32_t i = 0; i < count; i++) {
		uint16_t value;
		if (!getUInt16(value)) {
			delete result;
			return NULL;
		}
		result->push_back(value);
	}
	return result;
}

Int32List* MtpDataPacket::getAInt32() {
	uint32_t count;
	if (!getUInt32(count))
		return NULL;
	Int32List* result = new Int32List;
	for (uint32_t i = 0; i < count; i++) {
		int32_t value;
		if (!getInt32(value)) {
			delete result;
			return NULL;
		}
		result->push_back(value);
	}
	return result;
}

UInt32List* MtpDataPacket::getAUInt32() {
	uint32_t count;
	if (!getUInt32(count))
		return NULL;
	UInt32List* result = new UInt32List;
	for (uint32_t i = 0; i < count; i++) {
		uint32_t value;
		if (!getUInt32(value)) {
			delete result;
			return NULL;
		}
		result->push_back(value);
	}
	return result;
}

Int64List* MtpDataPacket::getAInt64() {
	uint32_t count;
	if (!getUInt32(count))
		return NULL;
	Int64List* result = new Int64List;
	for (uint32_t i = 0; i < count; i++) {
		int64_t value;
		if (!getInt64(value)) {
			delete result;
			return NULL;
		}
		result->push_back(value);
	}
	return result;
}

UInt64List* MtpDataPacket::getAUInt64() {
	uint32_t count;
	if (!getUInt32(count))
		return NULL;
	UInt64List* result = new UInt64List;
	for (uint32_t i = 0; i < count; i++) {
		uint64_t value;
		if (!getUInt64(value)) {
			delete result;
			return NULL;
		}
		result->push_back(value);
	}
	return result;
}

void MtpDataPacket::putInt8(int8_t value) {
	allocate(mOffset + 1);
	mBuffer[mOffset++] = (uint8_t)value;
	if (mPacketSize < mOffset)
		mPacketSize = mOffset;
}

void MtpDataPacket::putUInt8(uint8_t value) {
	allocate(mOffset + 1);
	mBuffer[mOffset++] = (uint8_t)value;
	if (mPacketSize < mOffset)
		mPacketSize = mOffset;
}

void MtpDataPacket::putInt16(int16_t value) {
	allocate(mOffset + 2);
	mBuffer[mOffset++] = (uint8_t)(value & 0xFF);
	mBuffer[mOffset++] = (uint8_t)((value >> 8) & 0xFF);
	if (mPacketSize < mOffset)
		mPacketSize = mOffset;
}

void MtpDataPacket::putUInt16(uint16_t value) {
	allocate(mOffset + 2);
	mBuffer[mOffset++] = (uint8_t)(value & 0xFF);
	mBuffer[mOffset++] = (uint8_t)((value >> 8) & 0xFF);
	if (mPacketSize < mOffset)
		mPacketSize = mOffset;
}

void MtpDataPacket::putInt32(int32_t value) {
	allocate(mOffset + 4);
	mBuffer[mOffset++] = (uint8_t)(value & 0xFF);
	mBuffer[mOffset++] = (uint8_t)((value >> 8) & 0xFF);
	mBuffer[mOffset++] = (uint8_t)((value >> 16) & 0xFF);
	mBuffer[mOffset++] = (uint8_t)((value >> 24) & 0xFF);
	if (mPacketSize < mOffset)
		mPacketSize = mOffset;
}

void MtpDataPacket::putUInt32(uint32_t value) {
	allocate(mOffset + 4);
	mBuffer[mOffset++] = (uint8_t)(value & 0xFF);
	mBuffer[mOffset++] = (uint8_t)((value >> 8) & 0xFF);
	mBuffer[mOffset++] = (uint8_t)((value >> 16) & 0xFF);
	mBuffer[mOffset++] = (uint8_t)((value >> 24) & 0xFF);
	if (mPacketSize < mOffset)
		mPacketSize = mOffset;
}

void MtpDataPacket::putInt64(int64_t value) {
	allocate(mOffset + 8);
	mBuffer[mOffset++] = (uint8_t)(value & 0xFF);
	mBuffer[mOffset++] = (uint8_t)((value >> 8) & 0xFF);
	mBuffer[mOffset++] = (uint8_t)((value >> 16) & 0xFF);
	mBuffer[mOffset++] = (uint8_t)((value >> 24) & 0xFF);
	mBuffer[mOffset++] = (uint8_t)((value >> 32) & 0xFF);
	mBuffer[mOffset++] = (uint8_t)((value >> 40) & 0xFF);
	mBuffer[mOffset++] = (uint8_t)((value >> 48) & 0xFF);
	mBuffer[mOffset++] = (uint8_t)((value >> 56) & 0xFF);
	if (mPacketSize < mOffset)
		mPacketSize = mOffset;
}

void MtpDataPacket::putUInt64(uint64_t value) {
	allocate(mOffset + 8);
	mBuffer[mOffset++] = (uint8_t)(value & 0xFF);
	mBuffer[mOffset++] = (uint8_t)((value >> 8) & 0xFF);
	mBuffer[mOffset++] = (uint8_t)((value >> 16) & 0xFF);
	mBuffer[mOffset++] = (uint8_t)((value >> 24) & 0xFF);
	mBuffer[mOffset++] = (uint8_t)((value >> 32) & 0xFF);
	mBuffer[mOffset++] = (uint8_t)((value >> 40) & 0xFF);
	mBuffer[mOffset++] = (uint8_t)((value >> 48) & 0xFF);
	mBuffer[mOffset++] = (uint8_t)((value >> 56) & 0xFF);
	if (mPacketSize < mOffset)
		mPacketSize = mOffset;
}

void MtpDataPacket::putInt128(const int128_t& value) {
	putInt32(value[0]);
	putInt32(value[1]);
	putInt32(value[2]);
	putInt32(value[3]);
}

void MtpDataPacket::putUInt128(const uint128_t& value) {
	putUInt32(value[0]);
	putUInt32(value[1]);
	putUInt32(value[2]);
	putUInt32(value[3]);
}

void MtpDataPacket::putInt128(int64_t value) {
	putInt64(value);
	putInt64(value < 0 ? -1 : 0);
}

void MtpDataPacket::putUInt128(uint64_t value) {
	putUInt64(value);
	putUInt64(0);
}

void MtpDataPacket::putAInt8(const int8_t* values, int count) {
	putUInt32(count);
	for (int i = 0; i < count; i++)
		putInt8(*values++);
}

void MtpDataPacket::putAUInt8(const uint8_t* values, int count) {
	putUInt32(count);
	for (int i = 0; i < count; i++)
		putUInt8(*values++);
}

void MtpDataPacket::putAInt16(const int16_t* values, int count) {
	putUInt32(count);
	for (int i = 0; i < count; i++)
		putInt16(*values++);
}

void MtpDataPacket::putAUInt16(const uint16_t* values, int count) {
	putUInt32(count);
	for (int i = 0; i < count; i++)
		putUInt16(*values++);
}

void MtpDataPacket::putAUInt16(const UInt16List* values) {
	size_t count = (values ? values->size() : 0);
	putUInt32(count);
	for (size_t i = 0; i < count; i++)
		putUInt16((*values)[i]);
}

void MtpDataPacket::putAInt32(const int32_t* values, int count) {
	putUInt32(count);
	for (int i = 0; i < count; i++)
		putInt32(*values++);
}

void MtpDataPacket::putAUInt32(const uint32_t* values, int count) {
	putUInt32(count);
	for (int i = 0; i < count; i++)
		putUInt32(*values++);
}

void MtpDataPacket::putAUInt32(const UInt32List* list) {
	if (!list) {
		putEmptyArray();
	} else {
		size_t size = list->size();
		putUInt32(size);
		for (size_t i = 0; i < size; i++)
			putUInt32((*list)[i]);
	}
}

void MtpDataPacket::putAInt64(const int64_t* values, int count) {
	putUInt32(count);
	for (int i = 0; i < count; i++)
		putInt64(*values++);
}

void MtpDataPacket::putAUInt64(const uint64_t* values, int count) {
	putUInt32(count);
	for (int i = 0; i < count; i++)
		putUInt64(*values++);
}

void MtpDataPacket::putString(const MtpStringBuffer& string) {
	string.writeToPacket(this);
}

void MtpDataPacket::putString(const char* s) {
	MtpStringBuffer string(s);
	string.writeToPacket(this);
}

void MtpDataPacket::putString(const uint16_t* string) {
	int count = 0;
	for (int i = 0; i <= MTP_STRING_MAX_CHARACTER_NUMBER; i++) {
		if (string[i])
			count++;
		else
			break;
	}
	putUInt8(count > 0 ? count + 1 : 0);
	for (int i = 0; i < count; i++)
		putUInt16(string[i]);
	// only terminate with zero if string is not empty
	if (count > 0)
		putUInt16(0);
}

#ifdef MTP_DEVICE
int MtpDataPacket::read(IMtpHandle *h) {
	int ret = h->read(mBuffer, MTP_BUFFER_SIZE);
	if (ret < MTP_CONTAINER_HEADER_SIZE)
		return -1;
	mPacketSize = ret;
	mOffset = MTP_CONTAINER_HEADER_SIZE;
	return ret;
}

int MtpDataPacket::write(IMtpHandle *h) {
	MtpPacket::putUInt32(MTP_CONTAINER_LENGTH_OFFSET, mPacketSize);
	MtpPacket::putUInt16(MTP_CONTAINER_TYPE_OFFSET, MTP_CONTAINER_TYPE_DATA);
	int ret = h->write(mBuffer, mPacketSize);
	return (ret < 0 ? ret : 0);
}

int MtpDataPacket::writeData(IMtpHandle *h, void* data, uint32_t length) {
	allocate(length + MTP_CONTAINER_HEADER_SIZE);
	memcpy(mBuffer + MTP_CONTAINER_HEADER_SIZE, data, length);
	length += MTP_CONTAINER_HEADER_SIZE;
	MtpPacket::putUInt32(MTP_CONTAINER_LENGTH_OFFSET, length);
	MtpPacket::putUInt16(MTP_CONTAINER_TYPE_OFFSET, MTP_CONTAINER_TYPE_DATA);
	int ret = h->write(mBuffer, length);
	return (ret < 0 ? ret : 0);
}

#endif // MTP_DEVICE

#ifdef MTP_HOST
int MtpDataPacket::read(struct usb_request *request) {
	// first read the header
	request->buffer = mBuffer;
	request->buffer_length = mBufferSize;
	int length = transfer(request);
	if (length >= MTP_CONTAINER_HEADER_SIZE) {
		// look at the length field to see if the data spans multiple packets
		uint32_t totalLength = MtpPacket::getUInt32(MTP_CONTAINER_LENGTH_OFFSET);
		allocate(totalLength);
		while (totalLength > static_cast<uint32_t>(length)) {
			request->buffer = mBuffer + length;
			request->buffer_length = totalLength - length;
			int ret = transfer(request);
			if (ret >= 0)
				length += ret;
			else {
				length = ret;
				break;
			}
		}
	}
	if (length >= 0)
		mPacketSize = length;
	return length;
}

int MtpDataPacket::readData(struct usb_request *request, void* buffer, int length) {
	int read = 0;
	while (read < length) {
		request->buffer = (char *)buffer + read;
		request->buffer_length = length - read;
		int ret = transfer(request);
		if (ret < 0) {
			return ret;
		}
		read += ret;
	}
	return read;
}

// Queue a read request.  Call readDataWait to wait for result
int MtpDataPacket::readDataAsync(struct usb_request *req) {
	if (usb_request_queue(req)) {
		MTPE("usb_endpoint_queue failed, errno: %d", errno);
		return -1;
	}
	return 0;
}

// Wait for result of readDataAsync
int MtpDataPacket::readDataWait(struct usb_device *device) {
	struct usb_request *req = usb_request_wait(device, -1);
	return (req ? req->actual_length : -1);
}

int MtpDataPacket::readDataHeader(struct usb_request *request) {
	request->buffer = mBuffer;
	request->buffer_length = request->max_packet_size;
	int length = transfer(request);
	if (length >= 0)
		mPacketSize = length;
	return length;
}

int MtpDataPacket::write(struct usb_request *request, UrbPacketDivisionMode divisionMode) {
	if (mPacketSize < MTP_CONTAINER_HEADER_SIZE || mPacketSize > MTP_BUFFER_SIZE) {
		MTPE("Illegal packet size.");
		return -1;
	}

	MtpPacket::putUInt32(MTP_CONTAINER_LENGTH_OFFSET, mPacketSize);
	MtpPacket::putUInt16(MTP_CONTAINER_TYPE_OFFSET, MTP_CONTAINER_TYPE_DATA);

	size_t processedBytes = 0;
	while (processedBytes < mPacketSize) {
		const size_t write_size =
				processedBytes == 0 && divisionMode == FIRST_PACKET_ONLY_HEADER ?
						MTP_CONTAINER_HEADER_SIZE : mPacketSize - processedBytes;
		request->buffer = mBuffer + processedBytes;
		request->buffer_length = write_size;
		const int result = transfer(request);
		if (result < 0) {
			MTPE("Failed to write bytes to the device.");
			return -1;
		}
		processedBytes += result;
	}

	return processedBytes == mPacketSize ? processedBytes : -1;
}

int MtpDataPacket::write(struct usb_request *request,
						 UrbPacketDivisionMode divisionMode,
						 int fd,
						 size_t payloadSize) {
	// Obtain the greatest multiple of minimum packet size that is not greater than
	// MTP_BUFFER_SIZE.
	if (request->max_packet_size <= 0) {
		MTPE("Cannot determine bulk transfer size due to illegal max packet size %d.",
			  request->max_packet_size);
		return -1;
	}
	const size_t maxBulkTransferSize =
			MTP_BUFFER_SIZE - (MTP_BUFFER_SIZE % request->max_packet_size);
	const size_t containerLength = payloadSize + MTP_CONTAINER_HEADER_SIZE;
	size_t processedBytes = 0;
	bool readError = false;

	// Bind the packet with given request.
	request->buffer = mBuffer;
	allocate(maxBulkTransferSize);

	while (processedBytes < containerLength) {
		size_t bulkTransferSize = 0;

		// prepare header.
		const bool headerSent = processedBytes != 0;
		if (!headerSent) {
			MtpPacket::putUInt32(MTP_CONTAINER_LENGTH_OFFSET, containerLength);
			MtpPacket::putUInt16(MTP_CONTAINER_TYPE_OFFSET, MTP_CONTAINER_TYPE_DATA);
			bulkTransferSize += MTP_CONTAINER_HEADER_SIZE;
		}

		// Prepare payload.
		if (headerSent || divisionMode == FIRST_PACKET_HAS_PAYLOAD) {
			const size_t processedPayloadBytes =
					headerSent ? processedBytes - MTP_CONTAINER_HEADER_SIZE : 0;
			const size_t maxRead = payloadSize - processedPayloadBytes;
			const size_t maxWrite = maxBulkTransferSize - bulkTransferSize;
			const size_t bulkTransferPayloadSize = std::min(maxRead, maxWrite);
			// prepare payload.
			if (!readError) {
				const ssize_t result = readExactBytes(
						fd,
						mBuffer + bulkTransferSize,
						bulkTransferPayloadSize);
				if (result < 0) {
					MTPE("Found an error while reading data from FD. Send 0 data instead.");
					readError = true;
				}
			}
			if (readError) {
				memset(mBuffer + bulkTransferSize, 0, bulkTransferPayloadSize);
			}
			bulkTransferSize += bulkTransferPayloadSize;
		}

		// Bulk transfer.
		mPacketSize = bulkTransferSize;
		request->buffer_length = bulkTransferSize;
		const int result = transfer(request);
		if (result != static_cast<ssize_t>(bulkTransferSize)) {
			// Cannot recover writing error.
			MTPE("Found an error while write data to MtpDevice.");
			return -1;
		}

		// Update variables.
		processedBytes += bulkTransferSize;
	}

	return readError ? -1 : processedBytes;
}

#endif // MTP_HOST

void* MtpDataPacket::getData(int* outLength) const {
	int length = mPacketSize - MTP_CONTAINER_HEADER_SIZE;
	if (length > 0) {
		void* result = malloc(length);
		if (result) {
			memcpy(result, mBuffer + MTP_CONTAINER_HEADER_SIZE, length);
			*outLength = length;
			return result;
		}
	}
	*outLength = 0;
	return NULL;
}