pjs/ipc/glue/SharedMemorySysV.h

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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* vim: sw=2 ts=8 et :
*/
/* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (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.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is Mozilla IPC.
*
* The Initial Developer of the Original Code is
* The Mozilla Foundation
* Portions created by the Initial Developer are Copyright (C) 2010
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
#ifndef mozilla_ipc_SharedMemorySysV_h
#define mozilla_ipc_SharedMemorySysV_h
#ifdef OS_LINUX
// SysV shared memory isn't available on Windows, but we define the
// following macro so that #ifdefs are clearer (compared to #ifdef
// OS_LINUX).
#define MOZ_HAVE_SHAREDMEMORYSYSV
#include "SharedMemory.h"
#include "nsDebug.h"
#include <errno.h>
#include <fcntl.h>
#include <string.h>
#include <sys/ipc.h>
#include <sys/shm.h>
//
// This is a low-level wrapper around platform shared memory. Don't
// use it directly; use Shmem allocated through IPDL interfaces.
//
namespace mozilla {
namespace ipc {
class SharedMemorySysV : public SharedMemory
{
public:
typedef int Handle;
SharedMemorySysV() :
mHandle(-1),
mData(nsnull),
mSize(0)
{
}
SharedMemorySysV(Handle aHandle) :
mHandle(aHandle),
mData(nsnull),
mSize(0)
{
}
virtual ~SharedMemorySysV()
{
shmdt(mData);
mHandle = -1;
mData = nsnull;
mSize = 0;
}
NS_OVERRIDE
virtual bool Create(size_t aNbytes)
{
int id = shmget(IPC_PRIVATE, aNbytes, IPC_CREAT | 0600);
if (id == -1)
return false;
mHandle = id;
if (!Map(aNbytes))
return false;
return true;
}
NS_OVERRIDE
virtual bool Map(size_t nBytes)
{
// already mapped
if (mData)
return true;
if (!IsHandleValid(mHandle))
return false;
void* mem = shmat(mHandle, nsnull, 0);
if (mem == (void*) -1) {
char warning[256];
snprintf(warning, sizeof(warning)-1,
"shmat(): %s (%d)\n", strerror(errno), errno);
NS_WARNING(warning);
return false;
}
// Mark the handle as deleted so that, should this process go away, the
// segment is cleaned up.
shmctl(mHandle, IPC_RMID, 0);
mData = mem;
mSize = nBytes;
#ifdef NS_DEBUG
struct shmid_ds info;
if (shmctl(mHandle, IPC_STAT, &info) < 0)
return false;
NS_ABORT_IF_FALSE(nBytes <= info.shm_segsz,
"Segment doesn't have enough space!");
#endif
return true;
}
NS_OVERRIDE
virtual size_t Size() const
{
return mSize;
}
NS_OVERRIDE
virtual void* memory() const
{
return mData;
}
NS_OVERRIDE
virtual SharedMemoryType Type() const
{
return TYPE_SYSV;
}
Handle GetHandle() const
{
NS_ABORT_IF_FALSE(IsHandleValid(mHandle), "invalid handle");
return mHandle;
}
static Handle NULLHandle()
{
return -1;
}
static bool IsHandleValid(Handle aHandle)
{
return aHandle != -1;
}
private:
Handle mHandle;
void* mData;
size_t mSize;
};
} // namespace ipc
} // namespace mozilla
#endif // OS_LINUX
#endif // ifndef mozilla_ipc_SharedMemorySysV_h