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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* vim: sw=2 ts=8 et :
*/
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef mozilla_ipc_SharedMemorySysV_h
#define mozilla_ipc_SharedMemorySysV_h
#if (defined(OS_LINUX) && !defined(ANDROID)) || defined(OS_BSD)
// 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 <stdio.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(nullptr)
{
}
SharedMemorySysV(Handle aHandle) :
mHandle(aHandle),
mData(nullptr)
{
}
virtual ~SharedMemorySysV()
{
shmdt(mData);
mHandle = -1;
mData = nullptr;
}
virtual bool Create(size_t aNbytes) MOZ_OVERRIDE
{
int id = shmget(IPC_PRIVATE, aNbytes, IPC_CREAT | 0600);
if (id == -1)
return false;
mHandle = id;
mAllocSize = aNbytes;
Created(aNbytes);
return Map(aNbytes);
}
virtual bool Map(size_t nBytes) MOZ_OVERRIDE
{
// already mapped
if (mData)
return true;
if (!IsHandleValid(mHandle))
return false;
void* mem = shmat(mHandle, nullptr, 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;
#ifdef 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
Mapped(nBytes);
return true;
}
virtual void* memory() const MOZ_OVERRIDE
{
return mData;
}
virtual SharedMemoryType Type() const MOZ_OVERRIDE
{
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;
};
} // namespace ipc
} // namespace mozilla
#endif // OS_LINUX
#endif // ifndef mozilla_ipc_SharedMemorySysV_h
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