public PosixPageFileBackedMemoryMapPager(string file, long?initialFileSize = null)
{
var instanceId = Interlocked.Increment(ref _counter);
_file = "/" + Syscall.getpid() + "-" + instanceId + "-" + file;
_fd = Rt.shm_open(_file, OpenFlags.O_RDWR | OpenFlags.O_CREAT, (int)FilePermissions.ALLPERMS);
if (_fd == -1)
{
PosixHelper.ThrowLastError(Marshal.GetLastWin32Error());
}
SysPageSize = Syscall.sysconf(SysconfName._SC_PAGESIZE);
if (initialFileSize.HasValue)
{
_totalAllocationSize = NearestSizeToPageSize(initialFileSize.Value);
}
_totalAllocationSize = NearestSizeToPageSize(_totalAllocationSize);
var result = Syscall.ftruncate(_fd, _totalAllocationSize);
if (result != 0)
{
PosixHelper.ThrowLastError(result);
}
NumberOfAllocatedPages = _totalAllocationSize / PageSize;
PagerState.Release();
PagerState = CreatePagerState();
}
public PosixMemoryMapPager(string file, long?initialFileSize = null)
{
_file = file;
//todo, do we need O_SYNC here?
//todo, ALLPERMS ?
_fd = Syscall.open(file, OpenFlags.O_RDWR | OpenFlags.O_CREAT | OpenFlags.O_SYNC,
FilePermissions.ALLPERMS);
if (_fd == -1)
{
PosixHelper.ThrowLastError(Marshal.GetLastWin32Error());
}
SysPageSize = Syscall.sysconf(SysconfName._SC_PAGESIZE);
_totalAllocationSize = GetFileSize();
if (_totalAllocationSize == 0 && initialFileSize.HasValue)
{
_totalAllocationSize = NearestSizeToPageSize(initialFileSize.Value);
}
if (_totalAllocationSize == 0 || _totalAllocationSize % SysPageSize != 0)
{
_totalAllocationSize = NearestSizeToPageSize(_totalAllocationSize);
var result = Syscall.ftruncate(_fd, _totalAllocationSize);
if (result != 0)
{
PosixHelper.ThrowLastError(result);
}
}
NumberOfAllocatedPages = _totalAllocationSize / PageSize;
PagerState.Release();
PagerState = CreatePagerState();
}
public override void AllocateMorePages(Transaction tx, long newLength)
{
ThrowObjectDisposedIfNeeded();
var newLengthAfterAdjustment = NearestSizeToPageSize(newLength);
if (newLengthAfterAdjustment < _totalAllocationSize)
{
throw new ArgumentException("Cannot set the length to less than the current length");
}
if (newLengthAfterAdjustment == _totalAllocationSize)
{
return;
}
var allocationSize = newLengthAfterAdjustment - _totalAllocationSize;
Syscall.ftruncate(_fd, (_totalAllocationSize + allocationSize));
if (TryAllocateMoreContinuousPages(allocationSize) == false)
{
PagerState newPagerState = CreatePagerState();
if (newPagerState == null)
{
var errorMessage = string.Format(
"Unable to allocate more pages - unsuccessfully tried to allocate continuous block of virtual memory with size = {0:##,###;;0} bytes",
(_totalAllocationSize + allocationSize));
throw new OutOfMemoryException(errorMessage);
}
newPagerState.DebugVerify(newLengthAfterAdjustment);
if (tx != null)
{
newPagerState.AddRef();
tx.AddPagerState(newPagerState);
}
var tmp = PagerState;
PagerState = newPagerState;
tmp.Release(); //replacing the pager state --> so one less reference for it
}
_totalAllocationSize += allocationSize;
NumberOfAllocatedPages = _totalAllocationSize / PageSize;
}
public void Truncate(long size)
{
var result = Syscall.ftruncate(_fd, (IntPtr)size);
if (result == -1)
{
var err = Marshal.GetLastWin32Error();
Syscall.ThrowLastError(err, "when truncating " + _filename);
}
result = Syscall.FSync(_fd);
if (result == -1)
{
var err = Marshal.GetLastWin32Error();
Syscall.ThrowLastError(err, "when fsycning " + _filename);
}
if (Syscall.CheckSyncDirectoryAllowed(_filename.FullPath) && Syscall.SyncDirectory(_filename.FullPath) == -1)
{
var err = Marshal.GetLastWin32Error();
Syscall.ThrowLastError(err, "when syncing dir for " + _filename);
}
}
