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      1 /*
      2  * Copyright (C) 2010 Apple Inc. All rights reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions
      6  * are met:
      7  * 1. Redistributions of source code must retain the above copyright
      8  *    notice, this list of conditions and the following disclaimer.
      9  * 2. Redistributions in binary form must reproduce the above copyright
     10  *    notice, this list of conditions and the following disclaimer in the
     11  *    documentation and/or other materials provided with the distribution.
     12  *
     13  * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
     14  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
     15  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     16  * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
     17  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     18  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     19  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     20  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     21  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     22  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
     23  * THE POSSIBILITY OF SUCH DAMAGE.
     24  */
     25 
     26 #include "config.h"
     27 #include "SharedMemory.h"
     28 
     29 #include "ArgumentDecoder.h"
     30 #include "ArgumentEncoder.h"
     31 #include "Arguments.h"
     32 #include "MachPort.h"
     33 #include <mach/mach_port.h>
     34 #include <mach/mach_vm.h>
     35 #include <mach/vm_map.h>
     36 #include <wtf/RefPtr.h>
     37 
     38 namespace WebKit {
     39 
     40 SharedMemory::Handle::Handle()
     41     : m_port(MACH_PORT_NULL)
     42     , m_size(0)
     43 {
     44 }
     45 
     46 SharedMemory::Handle::~Handle()
     47 {
     48     if (m_port)
     49         mach_port_deallocate(mach_task_self(), m_port);
     50 }
     51 
     52 bool SharedMemory::Handle::isNull() const
     53 {
     54     return !m_port;
     55 }
     56 
     57 void SharedMemory::Handle::encode(CoreIPC::ArgumentEncoder* encoder) const
     58 {
     59     encoder->encodeUInt64(m_size);
     60     encoder->encode(CoreIPC::MachPort(m_port, MACH_MSG_TYPE_MOVE_SEND));
     61     m_port = MACH_PORT_NULL;
     62 }
     63 
     64 bool SharedMemory::Handle::decode(CoreIPC::ArgumentDecoder* decoder, Handle& handle)
     65 {
     66     ASSERT(!handle.m_port);
     67     ASSERT(!handle.m_size);
     68 
     69     uint64_t size;
     70     if (!decoder->decodeUInt64(size))
     71         return false;
     72 
     73     CoreIPC::MachPort machPort;
     74     if (!decoder->decode(CoreIPC::Out(machPort)))
     75         return false;
     76 
     77     handle.m_size = size;
     78     handle.m_port = machPort.port();
     79     return true;
     80 }
     81 
     82 static inline void* toPointer(mach_vm_address_t address)
     83 {
     84     return reinterpret_cast<void*>(static_cast<uintptr_t>(address));
     85 }
     86 
     87 static inline mach_vm_address_t toVMAddress(void* pointer)
     88 {
     89     return static_cast<mach_vm_address_t>(reinterpret_cast<uintptr_t>(pointer));
     90 }
     91 
     92 PassRefPtr<SharedMemory> SharedMemory::create(size_t size)
     93 {
     94     ASSERT(size);
     95 
     96     mach_vm_address_t address;
     97     kern_return_t kr = mach_vm_allocate(mach_task_self(), &address, round_page(size), VM_FLAGS_ANYWHERE);
     98     if (kr != KERN_SUCCESS)
     99         return 0;
    100 
    101     // Create a Mach port that represents the shared memory.
    102     mach_port_t port;
    103     memory_object_size_t memoryObjectSize = round_page(size);
    104     kr = mach_make_memory_entry_64(mach_task_self(), &memoryObjectSize, address, VM_PROT_DEFAULT, &port, MACH_PORT_NULL);
    105 
    106     if (kr != KERN_SUCCESS) {
    107         mach_vm_deallocate(mach_task_self(), address, round_page(size));
    108         return 0;
    109     }
    110 
    111     ASSERT(memoryObjectSize >= round_page(size));
    112 
    113     RefPtr<SharedMemory> sharedMemory(adoptRef(new SharedMemory));
    114     sharedMemory->m_size = size;
    115     sharedMemory->m_data = toPointer(address);
    116     sharedMemory->m_port = port;
    117 
    118     return sharedMemory.release();
    119 }
    120 
    121 static inline vm_prot_t machProtection(SharedMemory::Protection protection)
    122 {
    123     switch (protection) {
    124     case SharedMemory::ReadOnly:
    125         return VM_PROT_READ;
    126     case SharedMemory::ReadWrite:
    127         return VM_PROT_READ | VM_PROT_WRITE;
    128     }
    129 
    130     ASSERT_NOT_REACHED();
    131     return VM_PROT_NONE;
    132 }
    133 
    134 PassRefPtr<SharedMemory> SharedMemory::create(const Handle& handle, Protection protection)
    135 {
    136     if (handle.isNull())
    137         return 0;
    138 
    139     // Map the memory.
    140     vm_prot_t vmProtection = machProtection(protection);
    141     mach_vm_address_t mappedAddress = 0;
    142     kern_return_t kr = mach_vm_map(mach_task_self(), &mappedAddress, handle.m_size, 0, VM_FLAGS_ANYWHERE, handle.m_port, 0, false, vmProtection, vmProtection, VM_INHERIT_NONE);
    143     if (kr != KERN_SUCCESS)
    144         return 0;
    145 
    146     RefPtr<SharedMemory> sharedMemory(adoptRef(new SharedMemory));
    147     sharedMemory->m_size = handle.m_size;
    148     sharedMemory->m_data = toPointer(mappedAddress);
    149     sharedMemory->m_port = MACH_PORT_NULL;
    150 
    151     return sharedMemory.release();
    152 }
    153 
    154 SharedMemory::~SharedMemory()
    155 {
    156     if (m_data) {
    157         kern_return_t kr = mach_vm_deallocate(mach_task_self(), toVMAddress(m_data), round_page(m_size));
    158         ASSERT_UNUSED(kr, kr == KERN_SUCCESS);
    159     }
    160 
    161     if (m_port) {
    162         kern_return_t kr = mach_port_deallocate(mach_task_self(), m_port);
    163         ASSERT_UNUSED(kr, kr == KERN_SUCCESS);
    164     }
    165 }
    166 
    167 bool SharedMemory::createHandle(Handle& handle, Protection protection)
    168 {
    169     ASSERT(!handle.m_port);
    170     ASSERT(!handle.m_size);
    171 
    172     mach_vm_address_t address = toVMAddress(m_data);
    173     memory_object_size_t size = round_page(m_size);
    174 
    175     mach_port_t port;
    176 
    177     if (protection == ReadWrite && m_port) {
    178         // Just re-use the port we have.
    179         port = m_port;
    180         if (mach_port_mod_refs(mach_task_self(), port, MACH_PORT_RIGHT_SEND, 1) != KERN_SUCCESS)
    181             return false;
    182     } else {
    183         // Create a mach port that represents the shared memory.
    184         kern_return_t kr = mach_make_memory_entry_64(mach_task_self(), &size, address, machProtection(protection), &port, MACH_PORT_NULL);
    185         if (kr != KERN_SUCCESS)
    186             return false;
    187 
    188         ASSERT(size >= round_page(m_size));
    189     }
    190 
    191     handle.m_port = port;
    192     handle.m_size = size;
    193 
    194     return true;
    195 }
    196 
    197 unsigned SharedMemory::systemPageSize()
    198 {
    199     return vm_page_size;
    200 }
    201 
    202 } // namespace WebKit
    203