path: root/Source/WebKit2/Platform/CoreIPC/mac/ConnectionMac.cpp

/*
 * Copyright (C) 2010 Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "Connection.h"

#include "CoreIPCMessageKinds.h"
#include "MachPort.h"
#include "MachUtilities.h"
#include "RunLoop.h"
#include <mach/vm_map.h>

using namespace std;

namespace CoreIPC {

static const size_t inlineMessageMaxSize = 4096;

enum {
    MessageBodyIsOOL = 1 << 31
};
    
void Connection::platformInvalidate()
{
    if (!m_isConnected)
        return;

    m_isConnected = false;

    ASSERT(m_sendPort);
    ASSERT(m_receivePort);

    // Unregister our ports.
    m_connectionQueue.unregisterMachPortEventHandler(m_sendPort);
    m_sendPort = MACH_PORT_NULL;

    m_connectionQueue.unregisterMachPortEventHandler(m_receivePort);
    m_receivePort = MACH_PORT_NULL;

    if (m_exceptionPort) {
        m_connectionQueue.unregisterMachPortEventHandler(m_exceptionPort);
        m_exceptionPort = MACH_PORT_NULL;
    }
}

void Connection::platformInitialize(Identifier identifier)
{
    m_exceptionPort = MACH_PORT_NULL;

    if (m_isServer) {
        m_receivePort = identifier;
        m_sendPort = MACH_PORT_NULL;
    } else {
        m_receivePort = MACH_PORT_NULL;
        m_sendPort = identifier;
    }
}

bool Connection::open()
{
    if (m_isServer) {
        ASSERT(m_receivePort);
        ASSERT(!m_sendPort);
        
    } else {
        ASSERT(!m_receivePort);
        ASSERT(m_sendPort);

        // Create the receive port.
        mach_port_allocate(mach_task_self(), MACH_PORT_RIGHT_RECEIVE, &m_receivePort);

        m_isConnected = true;
        
        // Send the initialize message, which contains a send right for the server to use.
        send(CoreIPCMessage::InitializeConnection, 0, MachPort(m_receivePort, MACH_MSG_TYPE_MAKE_SEND));

        // Set the dead name handler for our send port.
        initializeDeadNameSource();
    }
    
    // Change the message queue length for the receive port.
    setMachPortQueueLength(m_receivePort, MACH_PORT_QLIMIT_LARGE);

    // Register the data available handler.
    m_connectionQueue.registerMachPortEventHandler(m_receivePort, WorkQueue::MachPortDataAvailable, WorkItem::create(this, &Connection::receiveSourceEventHandler));

    // If we have an exception port, register the data available handler and send over the port to the other end.
    if (m_exceptionPort) {
        m_connectionQueue.registerMachPortEventHandler(m_exceptionPort, WorkQueue::MachPortDataAvailable, WorkItem::create(this, &Connection::exceptionSourceEventHandler));

        send(CoreIPCMessage::SetExceptionPort, 0, MachPort(m_exceptionPort, MACH_MSG_TYPE_MAKE_SEND));
    }

    return true;
}

static inline size_t machMessageSize(size_t bodySize, size_t numberOfPortDescriptors = 0, size_t numberOfOOLMemoryDescriptors = 0)
{
    size_t size = sizeof(mach_msg_header_t) + bodySize;
    if (numberOfPortDescriptors || numberOfOOLMemoryDescriptors) {
        size += sizeof(mach_msg_body_t);
        if (numberOfPortDescriptors)
            size += (numberOfPortDescriptors * sizeof(mach_msg_port_descriptor_t));
        if (numberOfOOLMemoryDescriptors)
            size += (numberOfOOLMemoryDescriptors * sizeof(mach_msg_ool_ports_descriptor_t));
    }
    return round_msg(size);
}

bool Connection::platformCanSendOutgoingMessages() const
{
    return true;
}

bool Connection::sendOutgoingMessage(MessageID messageID, PassOwnPtr<ArgumentEncoder> arguments)
{
    Vector<Attachment> attachments = arguments->releaseAttachments();
    
    size_t numberOfPortDescriptors = 0;
    size_t numberOfOOLMemoryDescriptors = 0;
    for (size_t i = 0; i < attachments.size(); ++i) {
        Attachment::Type type = attachments[i].type();
        if (type == Attachment::MachPortType)
            numberOfPortDescriptors++;
        else if (type == Attachment::MachOOLMemoryType)
            numberOfOOLMemoryDescriptors++;
    }
    
    size_t messageSize = machMessageSize(arguments->bufferSize(), numberOfPortDescriptors, numberOfOOLMemoryDescriptors);
    char buffer[inlineMessageMaxSize];

    bool messageBodyIsOOL = false;
    if (messageSize > sizeof(buffer)) {
        messageBodyIsOOL = true;

        attachments.append(Attachment(arguments->buffer(), arguments->bufferSize(), MACH_MSG_VIRTUAL_COPY, false));
        numberOfOOLMemoryDescriptors++;
        messageSize = machMessageSize(0, numberOfPortDescriptors, numberOfOOLMemoryDescriptors);
    }

    bool isComplex = (numberOfPortDescriptors + numberOfOOLMemoryDescriptors > 0);

    mach_msg_header_t* header = reinterpret_cast<mach_msg_header_t*>(&buffer);
    header->msgh_bits = isComplex ? MACH_MSGH_BITS(MACH_MSG_TYPE_COPY_SEND | MACH_MSGH_BITS_COMPLEX, 0) : MACH_MSGH_BITS(MACH_MSG_TYPE_COPY_SEND, 0);
    header->msgh_size = messageSize;
    header->msgh_remote_port = m_sendPort;
    header->msgh_local_port = MACH_PORT_NULL;
    header->msgh_id = messageID.toInt();
    if (messageBodyIsOOL)
        header->msgh_id |= MessageBodyIsOOL;

    uint8_t* messageData;

    if (isComplex) {
        mach_msg_body_t* body = reinterpret_cast<mach_msg_body_t*>(header + 1);
        body->msgh_descriptor_count = numberOfPortDescriptors + numberOfOOLMemoryDescriptors;

        uint8_t* descriptorData = reinterpret_cast<uint8_t*>(body + 1);
        for (size_t i = 0; i < attachments.size(); ++i) {
            Attachment attachment = attachments[i];

            mach_msg_descriptor_t* descriptor = reinterpret_cast<mach_msg_descriptor_t*>(descriptorData);
            switch (attachment.type()) {
            case Attachment::MachPortType:
                descriptor->port.name = attachment.port();
                descriptor->port.disposition = attachment.disposition();
                descriptor->port.type = MACH_MSG_PORT_DESCRIPTOR;            

                descriptorData += sizeof(mach_msg_port_descriptor_t);
                break;
            case Attachment::MachOOLMemoryType:
                descriptor->out_of_line.address = attachment.address();
                descriptor->out_of_line.size = attachment.size();
                descriptor->out_of_line.copy = attachment.copyOptions();
                descriptor->out_of_line.deallocate = attachment.deallocate();
                descriptor->out_of_line.type = MACH_MSG_OOL_DESCRIPTOR;            

                descriptorData += sizeof(mach_msg_ool_descriptor_t);
                break;
            default:
                ASSERT_NOT_REACHED();
            }
        }

        messageData = descriptorData;
    } else
        messageData = (uint8_t*)(header + 1);

    // Copy the data if it is not being sent out-of-line.
    if (!messageBodyIsOOL)
        memcpy(messageData, arguments->buffer(), arguments->bufferSize());

    ASSERT(m_sendPort);
    
    // Send the message.
    kern_return_t kr = mach_msg(header, MACH_SEND_MSG, messageSize, 0, MACH_PORT_NULL, MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL);
    if (kr != KERN_SUCCESS) {
        // FIXME: What should we do here?
    }

    return true;
}

void Connection::initializeDeadNameSource()
{
    m_connectionQueue.registerMachPortEventHandler(m_sendPort, WorkQueue::MachPortDeadNameNotification, WorkItem::create(this, &Connection::connectionDidClose));
}

static PassOwnPtr<ArgumentDecoder> createArgumentDecoder(mach_msg_header_t* header)
{
    if (!(header->msgh_bits & MACH_MSGH_BITS_COMPLEX)) {
        // We have a simple message.
        size_t bodySize = header->msgh_size - sizeof(mach_msg_header_t);
        uint8_t* body = reinterpret_cast<uint8_t*>(header + 1);
        
        return adoptPtr(new ArgumentDecoder(body, bodySize));
    }

    bool messageBodyIsOOL = header->msgh_id & MessageBodyIsOOL;

    mach_msg_body_t* body = reinterpret_cast<mach_msg_body_t*>(header + 1);
    mach_msg_size_t numDescriptors = body->msgh_descriptor_count;
    ASSERT(numDescriptors);

    // Build attachment list
    Deque<Attachment> attachments;
    uint8_t* descriptorData = reinterpret_cast<uint8_t*>(body + 1);

    // If the message body was sent out-of-line, don't treat the last descriptor
    // as an attachment, since it is really the message body.
    if (messageBodyIsOOL)
        --numDescriptors;

    for (mach_msg_size_t i = 0; i < numDescriptors; ++i) {
        mach_msg_descriptor_t* descriptor = reinterpret_cast<mach_msg_descriptor_t*>(descriptorData);

        switch (descriptor->type.type) {
        case MACH_MSG_PORT_DESCRIPTOR:
            attachments.append(Attachment(descriptor->port.name, descriptor->port.disposition));
            descriptorData += sizeof(mach_msg_port_descriptor_t);
            break;
        case MACH_MSG_OOL_DESCRIPTOR:
            attachments.append(Attachment(descriptor->out_of_line.address, descriptor->out_of_line.size,
                                          descriptor->out_of_line.copy, descriptor->out_of_line.deallocate));
            descriptorData += sizeof(mach_msg_ool_descriptor_t);
            break;
        default:
            ASSERT(false && "Unhandled descriptor type");
        }
    }

    if (messageBodyIsOOL) {
        mach_msg_descriptor_t* descriptor = reinterpret_cast<mach_msg_descriptor_t*>(descriptorData);
        ASSERT(descriptor->type.type == MACH_MSG_OOL_DESCRIPTOR);
        Attachment messageBodyAttachment(descriptor->out_of_line.address, descriptor->out_of_line.size,
                                         descriptor->out_of_line.copy, descriptor->out_of_line.deallocate);

        uint8_t* messageBody = static_cast<uint8_t*>(messageBodyAttachment.address());
        size_t messageBodySize = messageBodyAttachment.size();

        ArgumentDecoder* argumentDecoder;

        if (attachments.isEmpty())
            argumentDecoder = new ArgumentDecoder(messageBody, messageBodySize);
        else
            argumentDecoder = new ArgumentDecoder(messageBody, messageBodySize, attachments);

        vm_deallocate(mach_task_self(), reinterpret_cast<vm_address_t>(messageBodyAttachment.address()), messageBodyAttachment.size());

        return adoptPtr(argumentDecoder);
    }

    uint8_t* messageBody = descriptorData;
    size_t messageBodySize = header->msgh_size - (descriptorData - reinterpret_cast<uint8_t*>(header));

    return adoptPtr(new ArgumentDecoder(messageBody, messageBodySize, attachments));
}

// The receive buffer size should always include the maximum trailer size.
static const size_t receiveBufferSize = inlineMessageMaxSize + MAX_TRAILER_SIZE;
typedef Vector<char, receiveBufferSize> ReceiveBuffer;

static mach_msg_header_t* readFromMachPort(mach_port_t machPort, ReceiveBuffer& buffer)
{
    buffer.resize(receiveBufferSize);

    mach_msg_header_t* header = reinterpret_cast<mach_msg_header_t*>(buffer.data());
    kern_return_t kr = mach_msg(header, MACH_RCV_MSG | MACH_RCV_LARGE | MACH_RCV_TIMEOUT, 0, buffer.size(), machPort, 0, MACH_PORT_NULL);
    if (kr == MACH_RCV_TIMED_OUT)
        return 0;

    if (kr == MACH_RCV_TOO_LARGE) {
        // The message was too large, resize the buffer and try again.
        buffer.resize(header->msgh_size + MAX_TRAILER_SIZE);
        header = reinterpret_cast<mach_msg_header_t*>(buffer.data());
        
        kr = mach_msg(header, MACH_RCV_MSG | MACH_RCV_LARGE | MACH_RCV_TIMEOUT, 0, buffer.size(), machPort, 0, MACH_PORT_NULL);
        ASSERT(kr != MACH_RCV_TOO_LARGE);
    }

    if (kr != MACH_MSG_SUCCESS) {
        ASSERT_NOT_REACHED();
        return 0;
    }

    return header;
}

void Connection::receiveSourceEventHandler()
{
    ReceiveBuffer buffer;

    mach_msg_header_t* header = readFromMachPort(m_receivePort, buffer);
    if (!header)
        return;

    MessageID messageID = MessageID::fromInt(header->msgh_id);
    OwnPtr<ArgumentDecoder> arguments = createArgumentDecoder(header);
    ASSERT(arguments);

    if (messageID == MessageID(CoreIPCMessage::InitializeConnection)) {
        ASSERT(m_isServer);
        ASSERT(!m_isConnected);
        ASSERT(!m_sendPort);

        MachPort port;
        if (!arguments->decode(port)) {
            // FIXME: Disconnect.
            return;
        }

        m_sendPort = port.port();
        
        // Set the dead name source if needed.
        if (m_sendPort)
            initializeDeadNameSource();
        
        m_isConnected = true;

        // Send any pending outgoing messages.
        sendOutgoingMessages();
        
        return;
    }

    if (messageID == MessageID(CoreIPCMessage::SetExceptionPort)) {
        MachPort exceptionPort;
        if (!arguments->decode(exceptionPort))
            return;

        setMachExceptionPort(exceptionPort.port());
        return;
    }

    processIncomingMessage(messageID, arguments.release());
}    

void Connection::exceptionSourceEventHandler()
{
    ReceiveBuffer buffer;

    mach_msg_header_t* header = readFromMachPort(m_exceptionPort, buffer);
    if (!header)
        return;

    // We've read the exception message. Now send it on to the real exception port.

    // The remote port should have a send once right.
    ASSERT(MACH_MSGH_BITS_REMOTE(header->msgh_bits) == MACH_MSG_TYPE_MOVE_SEND_ONCE);

    // Now get the real exception port.
    mach_port_t exceptionPort = machExceptionPort();

    // First, get the complex bit from the source message.
    mach_msg_bits_t messageBits = header->msgh_bits & MACH_MSGH_BITS_COMPLEX;
    messageBits |= MACH_MSGH_BITS(MACH_MSG_TYPE_COPY_SEND, MACH_MSG_TYPE_MOVE_SEND_ONCE);

    header->msgh_bits = messageBits;
    header->msgh_local_port = header->msgh_remote_port;
    header->msgh_remote_port = exceptionPort;

    // Now send along the message.
    kern_return_t kr = mach_msg(header, MACH_SEND_MSG, header->msgh_size, 0, MACH_PORT_NULL, MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL);
    if (kr != KERN_SUCCESS) {
        LOG_ERROR("Failed to send message to real exception port, error %x", kr);
        ASSERT_NOT_REACHED();
    }

    connectionDidClose();
}

void Connection::setShouldCloseConnectionOnMachExceptions()
{
    ASSERT(m_exceptionPort == MACH_PORT_NULL);

    if (mach_port_allocate(mach_task_self(), MACH_PORT_RIGHT_RECEIVE, &m_exceptionPort) != KERN_SUCCESS)
        ASSERT_NOT_REACHED();

    if (mach_port_insert_right(mach_task_self(), m_exceptionPort, m_exceptionPort, MACH_MSG_TYPE_MAKE_SEND) != KERN_SUCCESS)
        ASSERT_NOT_REACHED();
}

} // namespace CoreIPC