private MemoryMappedFile(SafeMemoryMappedFileHandle handle)
{
Debug.Assert(handle != null && !handle.IsClosed && !handle.IsInvalid, "handle is null, closed, or invalid");
_handle = handle;
_leaveOpen = true; // No FileStream to dispose of in this case.
}
private static Microsoft.Win32.SafeHandles.SafeMemoryMappedFileHandle CreateCore(SafeFileHandle fileHandle, string mapName, HandleInheritability inheritability, MemoryMappedFileSecurity memoryMappedFileSecurity, MemoryMappedFileAccess access, MemoryMappedFileOptions options, long capacity)
{
Microsoft.Win32.SafeHandles.SafeMemoryMappedFileHandle handle = null;
object obj2;
Microsoft.Win32.UnsafeNativeMethods.SECURITY_ATTRIBUTES lpAttributes = GetSecAttrs(inheritability, memoryMappedFileSecurity, out obj2);
int dwMaximumSizeLow = (int)(((ulong)capacity) & 0xffffffffL);
int dwMaximumSizeHigh = (int)(capacity >> 0x20);
try
{
handle = Microsoft.Win32.UnsafeNativeMethods.CreateFileMapping(fileHandle, lpAttributes, GetPageAccess(access) | options, dwMaximumSizeHigh, dwMaximumSizeLow, mapName);
int errorCode = Marshal.GetLastWin32Error();
if (!handle.IsInvalid && (errorCode == 0xb7))
{
handle.Dispose();
System.IO.__Error.WinIOError(errorCode, string.Empty);
return(handle);
}
if (handle.IsInvalid)
{
System.IO.__Error.WinIOError(errorCode, string.Empty);
}
}
finally
{
if (obj2 != null)
{
((GCHandle)obj2).Free();
}
}
return(handle);
}
private static FileStream CreateSharedBackingObject(
Interop.libc.MemoryMappedProtections protections, long capacity,
out string mapName, out SafeMemoryMappedFileHandle.FileStreamSource fileStreamSource)
{
// The POSIX shared memory object name must begin with '/'. After that we just want something short and unique.
mapName = "/" + MemoryMapObjectFilePrefix + Guid.NewGuid().ToString("N");
fileStreamSource = SafeMemoryMappedFileHandle.FileStreamSource.ManufacturedSharedMemory;
// Determine the flags to use when creating the shared memory object
Interop.libc.OpenFlags flags = (protections & Interop.libc.MemoryMappedProtections.PROT_WRITE) != 0 ?
Interop.libc.OpenFlags.O_RDWR :
Interop.libc.OpenFlags.O_RDONLY;
flags |= Interop.libc.OpenFlags.O_CREAT | Interop.libc.OpenFlags.O_EXCL; // CreateNew
// Determine the permissions with which to create the file
Interop.libc.Permissions perms = default(Interop.libc.Permissions);
if ((protections & Interop.libc.MemoryMappedProtections.PROT_READ) != 0)
perms |= Interop.libc.Permissions.S_IRUSR;
if ((protections & Interop.libc.MemoryMappedProtections.PROT_WRITE) != 0)
perms |= Interop.libc.Permissions.S_IWUSR;
if ((protections & Interop.libc.MemoryMappedProtections.PROT_EXEC) != 0)
perms |= Interop.libc.Permissions.S_IXUSR;
// Create the shared memory object. Then enlarge it to the requested capacity.
int fd;
Interop.CheckIo(fd = Interop.libc.shm_open(mapName, flags, (int)perms), mapName);
SafeFileHandle fileHandle = new SafeFileHandle((IntPtr)fd, ownsHandle: true);
// Wrap the handle in a stream and return it.
var fs = new FileStream(fileHandle, TranslateProtectionsToFileAccess(protections));
fs.SetLength(capacity);
return fs;
}
public static MemoryMappedFile CreateFromFile(string path, FileMode mode, string mapName, long capacity, MemoryMappedFileAccess access)
{
if (path == null)
{
throw new ArgumentNullException("path");
}
if ((mapName != null) && (mapName.Length == 0))
{
throw new ArgumentException(System.SR.GetString("Argument_MapNameEmptyString"));
}
if (capacity < 0L)
{
throw new ArgumentOutOfRangeException("capacity", System.SR.GetString("ArgumentOutOfRange_PositiveOrDefaultCapacityRequired"));
}
if ((access < MemoryMappedFileAccess.ReadWrite) || (access > MemoryMappedFileAccess.ReadWriteExecute))
{
throw new ArgumentOutOfRangeException("access");
}
if (mode == FileMode.Append)
{
throw new ArgumentException(System.SR.GetString("Argument_NewMMFAppendModeNotAllowed"), "mode");
}
if (access == MemoryMappedFileAccess.Write)
{
throw new ArgumentException(System.SR.GetString("Argument_NewMMFWriteAccessNotAllowed"), "access");
}
bool existed = File.Exists(path);
FileStream fileStream = new FileStream(path, mode, GetFileStreamFileSystemRights(access), FileShare.None, 0x1000, FileOptions.None);
if ((capacity == 0L) && (fileStream.Length == 0L))
{
CleanupFile(fileStream, existed, path);
throw new ArgumentException(System.SR.GetString("Argument_EmptyFile"));
}
if ((access == MemoryMappedFileAccess.Read) && (capacity > fileStream.Length))
{
CleanupFile(fileStream, existed, path);
throw new ArgumentException(System.SR.GetString("Argument_ReadAccessWithLargeCapacity"));
}
if (capacity == 0L)
{
capacity = fileStream.Length;
}
if (fileStream.Length > capacity)
{
CleanupFile(fileStream, existed, path);
throw new ArgumentOutOfRangeException("capacity", System.SR.GetString("ArgumentOutOfRange_CapacityGEFileSizeRequired"));
}
Microsoft.Win32.SafeHandles.SafeMemoryMappedFileHandle handle = null;
try
{
handle = CreateCore(fileStream.SafeFileHandle, mapName, HandleInheritability.None, null, access, MemoryMappedFileOptions.None, capacity);
}
catch
{
CleanupFile(fileStream, existed, path);
throw;
}
return(new MemoryMappedFile(handle, fileStream, false));
}
private MemoryMappedFile(SafeMemoryMappedFileHandle handle, FileStream fileStream, bool leaveOpen) {
Debug.Assert(handle != null && !handle.IsClosed && !handle.IsInvalid, "handle is null, closed, or invalid");
Debug.Assert(fileStream != null, "fileStream is null");
_handle = handle;
_fileStream = fileStream;
_leaveOpen = leaveOpen;
}
public static SafeMemoryMappedViewHandle MapViewOfFile(
SafeMemoryMappedFileHandle hFileMappingObject,
int desiredAccess,
long fileOffset,
UIntPtr numberOfBytesToMap)
{
return Interop.mincore.MapViewOfFileFromApp(hFileMappingObject, desiredAccess, fileOffset, numberOfBytesToMap);
}
private MemoryMappedFile(SafeMemoryMappedFileHandle handle)
{
Debug.Assert(handle != null);
Debug.Assert(!handle.IsClosed);
Debug.Assert(!handle.IsInvalid);
_handle = handle;
_leaveOpen = true; // No FileStream to dispose of in this case.
}
private MemoryMappedFile(SafeMemoryMappedFileHandle handle, FileStream fileStream, bool leaveOpen)
{
Debug.Assert(handle != null);
Debug.Assert(!handle.IsClosed);
Debug.Assert(!handle.IsInvalid);
Debug.Assert(fileStream != null);
_handle = handle;
_fileStream = fileStream;
_leaveOpen = leaveOpen;
}
public static SafeMemoryMappedViewHandle MapViewOfFile(
SafeMemoryMappedFileHandle hFileMappingObject,
int desiredAccess,
long fileOffset,
UIntPtr numberOfBytesToMap)
{
// split the long into two ints
int offsetHigh, offsetLow;
SplitLong(fileOffset, out offsetHigh, out offsetLow);
return Interop.Kernel32.MapViewOfFile(hFileMappingObject, desiredAccess, offsetHigh, offsetLow, numberOfBytesToMap);
}
internal static MemoryMappedView CreateView(SafeMemoryMappedFileHandle memMappedFileHandle, MemoryMappedFileAccess access, long offset, long size)
{
ulong num3;
ulong num = (ulong) (offset % ((long) MemoryMappedFile.GetSystemPageAllocationGranularity()));
ulong num2 = ((ulong) offset) - num;
if (size != 0L)
{
num3 = ((ulong) size) + num;
}
else
{
num3 = 0L;
}
if ((IntPtr.Size == 4) && (num3 > 0xffffffffL))
{
throw new ArgumentOutOfRangeException("size", System.SR.GetString("ArgumentOutOfRange_CapacityLargerThanLogicalAddressSpaceNotAllowed"));
}
Microsoft.Win32.UnsafeNativeMethods.MEMORYSTATUSEX lpBuffer = new Microsoft.Win32.UnsafeNativeMethods.MEMORYSTATUSEX();
Microsoft.Win32.UnsafeNativeMethods.GlobalMemoryStatusEx(lpBuffer);
ulong ullTotalVirtual = lpBuffer.ullTotalVirtual;
if (num3 >= ullTotalVirtual)
{
throw new IOException(System.SR.GetString("IO_NotEnoughMemory"));
}
uint dwFileOffsetLow = (uint) (num2 & 0xffffffffL);
uint dwFileOffsetHigh = (uint) (num2 >> 0x20);
SafeMemoryMappedViewHandle address = Microsoft.Win32.UnsafeNativeMethods.MapViewOfFile(memMappedFileHandle, MemoryMappedFile.GetFileMapAccess(access), dwFileOffsetHigh, dwFileOffsetLow, new UIntPtr(num3));
if (address.IsInvalid)
{
System.IO.__Error.WinIOError(Marshal.GetLastWin32Error(), string.Empty);
}
Microsoft.Win32.UnsafeNativeMethods.MEMORY_BASIC_INFORMATION buffer = new Microsoft.Win32.UnsafeNativeMethods.MEMORY_BASIC_INFORMATION();
Microsoft.Win32.UnsafeNativeMethods.VirtualQuery(address, ref buffer, (IntPtr) Marshal.SizeOf(buffer));
ulong regionSize = (ulong) buffer.RegionSize;
if ((buffer.State & 0x2000) != 0)
{
Microsoft.Win32.UnsafeNativeMethods.VirtualAlloc(address, (UIntPtr) regionSize, 0x1000, MemoryMappedFile.GetPageAccess(access));
int errorCode = Marshal.GetLastWin32Error();
if (address.IsInvalid)
{
System.IO.__Error.WinIOError(errorCode, string.Empty);
}
}
if (size == 0L)
{
size = (long) (regionSize - num);
}
address.Initialize(((ulong) size) + num);
return new MemoryMappedView(address, (long) num, size, access);
}
private static Microsoft.Win32.SafeHandles.SafeMemoryMappedFileHandle OpenCore(string mapName, HandleInheritability inheritability, int desiredAccessRights, bool createOrOpen)
{
Microsoft.Win32.SafeHandles.SafeMemoryMappedFileHandle handle = Microsoft.Win32.UnsafeNativeMethods.OpenFileMapping(desiredAccessRights, (inheritability & HandleInheritability.Inheritable) != HandleInheritability.None, mapName);
int errorCode = Marshal.GetLastWin32Error();
if (handle.IsInvalid)
{
if (createOrOpen && (errorCode == 2))
{
throw new ArgumentException(System.SR.GetString("Argument_NewMMFWriteAccessNotAllowed"), "access");
}
System.IO.__Error.WinIOError(errorCode, string.Empty);
}
return(handle);
}
private static FileStream CreateSharedBackingObject(
Interop.libc.MemoryMappedProtections protections, long capacity,
out string mapName, out SafeMemoryMappedFileHandle.FileStreamSource fileHandleSource)
{
mapName = MemoryMapObjectFilePrefix + Guid.NewGuid().ToString("N") + ".tmp";
fileHandleSource = SafeMemoryMappedFileHandle.FileStreamSource.ManufacturedFile;
FileAccess access =
(protections & (Interop.libc.MemoryMappedProtections.PROT_READ | Interop.libc.MemoryMappedProtections.PROT_WRITE)) != 0 ? FileAccess.ReadWrite :
(protections & (Interop.libc.MemoryMappedProtections.PROT_WRITE)) != 0 ? FileAccess.Write :
FileAccess.Read;
const int DefaultBufferSize = 0x1000;
var fs = new FileStream(Path.Combine(Path.GetTempPath(), mapName),
FileMode.CreateNew, TranslateProtectionsToFileAccess(protections), FileShare.ReadWrite,
DefaultBufferSize, FileOptions.DeleteOnClose);
fs.SetLength(capacity);
return fs;
}
private MemoryMappedFile(Microsoft.Win32.SafeHandles.SafeMemoryMappedFileHandle handle, FileStream fileStream, bool leaveOpen)
{
this._handle = handle;
this._fileStream = fileStream;
this._leaveOpen = leaveOpen;
}
private MemoryMappedFile(Microsoft.Win32.SafeHandles.SafeMemoryMappedFileHandle handle)
{
this._handle = handle;
this._leaveOpen = true;
}
internal static extern SafeMemoryMappedViewHandle MapViewOfFile(
SafeMemoryMappedFileHandle hFileMappingObject,
int dwDesiredAccess,
int dwFileOffsetHigh,
int dwFileOffsetLow,
UIntPtr dwNumberOfBytesToMap);
internal static extern int GetFileSize(SafeMemoryMappedFileHandle hFile, out int highSize);
internal static int GetFileSize (SafeMemoryMappedFileHandle hFile, out int highSize)
{
highSize = Int32.MaxValue;
return Int32.MaxValue;
}
internal unsafe static MemoryMappedView CreateView(SafeMemoryMappedFileHandle memMappedFileHandle,
MemoryMappedFileAccess access, Int64 offset, Int64 size) {
// MapViewOfFile can only create views that start at a multiple of the system memory allocation
// granularity. We decided to hide this restriction form the user by creating larger views than the
// user requested and hiding the parts that the user did not request. extraMemNeeded is the amount of
// extra memory we allocate before the start of the requested view. MapViewOfFile will also round the
// capacity of the view to the nearest multiple of the system page size. Once again, we hide this
// from the user by preventing them from writing to any memory that they did not request.
ulong extraMemNeeded = (ulong)offset % (ulong)MemoryMappedFile.GetSystemPageAllocationGranularity();
// newOffset takes into account the fact that we have some extra memory allocated before the requested view
ulong newOffset = (ulong)offset - extraMemNeeded;
Debug.Assert(newOffset >= 0, "newOffset = (offset - extraMemNeeded) < 0");
// determine size to pass to MapViewOfFile
ulong nativeSize;
if (size != MemoryMappedFile.DefaultSize) {
nativeSize = (ulong)size + (ulong)extraMemNeeded;
}
else {
nativeSize = 0;
}
if (IntPtr.Size == 4 && nativeSize > UInt32.MaxValue) {
throw new ArgumentOutOfRangeException("size", SR.GetString(SR.ArgumentOutOfRange_CapacityLargerThanLogicalAddressSpaceNotAllowed));
}
// if request is >= than total virtual, then MapViewOfFile will fail with meaningless error message
// "the parameter is incorrect"; this provides better error message in advance
UnsafeNativeMethods.MEMORYSTATUSEX memStatus = new UnsafeNativeMethods.MEMORYSTATUSEX();
bool result = UnsafeNativeMethods.GlobalMemoryStatusEx(ref memStatus);
ulong totalVirtual = memStatus.ullTotalVirtual;
if (nativeSize >= totalVirtual) {
throw new IOException(SR.GetString(SR.IO_NotEnoughMemory));
}
// split the Int64 into two ints
uint offsetLow = (uint)(newOffset & 0x00000000FFFFFFFFL);
uint offsetHigh = (uint)(newOffset >> 32);
// create the view
SafeMemoryMappedViewHandle viewHandle = UnsafeNativeMethods.MapViewOfFile(memMappedFileHandle,
MemoryMappedFile.GetFileMapAccess(access), offsetHigh, offsetLow, new UIntPtr(nativeSize));
if (viewHandle.IsInvalid) {
__Error.WinIOError(Marshal.GetLastWin32Error(), String.Empty);
}
// Query the view for its size and allocation type
UnsafeNativeMethods.MEMORY_BASIC_INFORMATION viewInfo = new UnsafeNativeMethods.MEMORY_BASIC_INFORMATION();
UnsafeNativeMethods.VirtualQuery(viewHandle, ref viewInfo, (IntPtr)Marshal.SizeOf(viewInfo));
ulong viewSize = (ulong)viewInfo.RegionSize;
// Allocate the pages if we were using the MemoryMappedFileOptions.DelayAllocatePages option
// OR check if the allocated view size is smaller than the expected native size
// If multiple overlapping views are created over the file mapping object, the pages in a given region
// could have different attributes(MEM_RESERVE OR MEM_COMMIT) as MapViewOfFile preserves coherence between
// views created on a mapping object backed by same file.
// In which case, the viewSize will be smaller than nativeSize required and viewState could be MEM_COMMIT
// but more pages may need to be committed in the region.
// This is because, VirtualQuery function(that internally invokes VirtualQueryEx function) returns the attributes
// and size of the region of pages with matching attributes starting from base address.
// VirtualQueryEx: http://msdn.microsoft.com/en-us/library/windows/desktop/aa366907(v=vs.85).aspx
if (((viewInfo.State & UnsafeNativeMethods.MEM_RESERVE) != 0) || (viewSize < nativeSize)) {
ulong allocSize = (nativeSize == 0) ? viewSize : nativeSize;
IntPtr tempHandle = UnsafeNativeMethods.VirtualAlloc(viewHandle, (UIntPtr)allocSize, UnsafeNativeMethods.MEM_COMMIT,
MemoryMappedFile.GetPageAccess(access));
int lastError = Marshal.GetLastWin32Error();
// The following is commented out for backward compatibility.
// Previously releases failed to check for this error so introducing this check
// could cause new/different exceptions in existing code paths.
// if (tempHandle == IntPtr.Zero) {
// __Error.WinIOError(lastError, String.Empty);
// }
// again query the view for its new size
viewInfo = new UnsafeNativeMethods.MEMORY_BASIC_INFORMATION();
UnsafeNativeMethods.VirtualQuery(viewHandle, ref viewInfo, (IntPtr)Marshal.SizeOf(viewInfo));
viewSize = (ulong)viewInfo.RegionSize;
}
// if the user specified DefaultSize as the size, we need to get the actual size
if (size == MemoryMappedFile.DefaultSize) {
size = (Int64)(viewSize - extraMemNeeded);
}
else {
Debug.Assert(viewSize >= (ulong)size, "viewSize < size");
}
viewHandle.Initialize((ulong)size + extraMemNeeded);
MemoryMappedView mmv = new MemoryMappedView(viewHandle, (long)extraMemNeeded, size, access);
return mmv;
}
private MemoryMappedFile(SafeMemoryMappedFileHandle handle)
{
this._handle = handle;
}
internal static MemoryMappedView CreateView(SafeMemoryMappedFileHandle safeMemoryMappedFileHandle, MemoryMappedFileAccess access, long offset, long size)
{
// http://msdn.microsoft.com/en-us/library/windows/desktop/aa366548(v=vs.85).aspx
UnsafeNativeMethods.SYSTEM_INFO info = new UnsafeNativeMethods.SYSTEM_INFO();
UnsafeNativeMethods.GetSystemInfo(ref info);
// To calculate where to start the file mapping, round down the
// offset of the data into the memory-mapped file to the nearest multiple of the
// system allocation granularity.
long fileMapStart = (offset / info.dwAllocationGranularity) * info.dwAllocationGranularity;
// How large will the file mapping object be?
long mapViewSize = (offset % info.dwAllocationGranularity) + size;
// The data of interest is not necessarily at the beginning of the
// view, so determine how far into the view to set the pointer.
long viewDelta = offset - fileMapStart;
SafeMemoryMappedViewHandle safeHandle = UnsafeNativeMethods.MapViewOfFile(safeMemoryMappedFileHandle, access.ToMapViewFileAccess(), (ulong)fileMapStart, new UIntPtr((ulong)mapViewSize));
var lastWin32Error = Marshal.GetLastWin32Error();
if (safeHandle.IsInvalid)
{
if (lastWin32Error == UnsafeNativeMethods.ERROR_FILE_NOT_FOUND)
throw new FileNotFoundException();
throw new System.IO.IOException(UnsafeNativeMethods.GetMessage(lastWin32Error));
}
return new MemoryMappedView(safeHandle, viewDelta, size);
}
public unsafe static MemoryMappedView CreateView(SafeMemoryMappedFileHandle memMappedFileHandle,
MemoryMappedFileAccess access, long offset, long size)
{
// MapViewOfFile can only create views that start at a multiple of the system memory allocation
// granularity. We decided to hide this restriction form the user by creating larger views than the
// user requested and hiding the parts that the user did not request. extraMemNeeded is the amount of
// extra memory we allocate before the start of the requested view. MapViewOfFile will also round the
// capacity of the view to the nearest multiple of the system page size. Once again, we hide this
// from the user by preventing them from writing to any memory that they did not request.
ulong nativeSize, extraMemNeeded, newOffset;
ValidateSizeAndOffset(
size, offset, GetSystemPageAllocationGranularity(),
out nativeSize, out extraMemNeeded, out newOffset);
// if request is >= than total virtual, then MapViewOfFile will fail with meaningless error message
// "the parameter is incorrect"; this provides better error message in advance
Interop.MEMORYSTATUSEX memStatus;
memStatus.dwLength = (uint)sizeof(Interop.MEMORYSTATUSEX);
Interop.mincore.GlobalMemoryStatusEx(out memStatus);
ulong totalVirtual = memStatus.ullTotalVirtual;
if (nativeSize >= totalVirtual)
{
throw new IOException(SR.IO_NotEnoughMemory);
}
// split the long into two ints
int offsetLow = unchecked((int)(newOffset & 0x00000000FFFFFFFFL));
int offsetHigh = unchecked((int)(newOffset >> 32));
// create the view
SafeMemoryMappedViewHandle viewHandle = Interop.mincore.MapViewOfFile(memMappedFileHandle,
(int)MemoryMappedFile.GetFileMapAccess(access), offsetHigh, offsetLow, new UIntPtr(nativeSize));
if (viewHandle.IsInvalid)
{
throw Win32Marshal.GetExceptionForLastWin32Error();
}
// Query the view for its size and allocation type
Interop.MEMORY_BASIC_INFORMATION viewInfo = new Interop.MEMORY_BASIC_INFORMATION();
Interop.mincore.VirtualQuery(viewHandle, ref viewInfo, (UIntPtr)Marshal.SizeOf(viewInfo));
ulong viewSize = (ulong)viewInfo.RegionSize;
// Allocate the pages if we were using the MemoryMappedFileOptions.DelayAllocatePages option
// OR check if the allocated view size is smaller than the expected native size
// If multiple overlapping views are created over the file mapping object, the pages in a given region
// could have different attributes(MEM_RESERVE OR MEM_COMMIT) as MapViewOfFile preserves coherence between
// views created on a mapping object backed by same file.
// In which case, the viewSize will be smaller than nativeSize required and viewState could be MEM_COMMIT
// but more pages may need to be committed in the region.
// This is because, VirtualQuery function(that internally invokes VirtualQueryEx function) returns the attributes
// and size of the region of pages with matching attributes starting from base address.
// VirtualQueryEx: http://msdn.microsoft.com/en-us/library/windows/desktop/aa366907(v=vs.85).aspx
if (((viewInfo.State & Interop.MEM_RESERVE) != 0) || (viewSize < nativeSize))
{
IntPtr tempHandle = Interop.mincore.VirtualAlloc(viewHandle, (UIntPtr)nativeSize, Interop.MEM_COMMIT,
MemoryMappedFile.GetPageAccess(access));
int lastError = Marshal.GetLastWin32Error();
if (viewHandle.IsInvalid)
{
throw Win32Marshal.GetExceptionForWin32Error(lastError);
}
// again query the view for its new size
viewInfo = new Interop.MEMORY_BASIC_INFORMATION();
Interop.mincore.VirtualQuery(viewHandle, ref viewInfo, (UIntPtr)Marshal.SizeOf(viewInfo));
viewSize = (ulong)viewInfo.RegionSize;
}
// if the user specified DefaultSize as the size, we need to get the actual size
if (size == MemoryMappedFile.DefaultSize)
{
size = (long)(viewSize - extraMemNeeded);
}
else
{
Debug.Assert(viewSize >= (ulong)size, "viewSize < size");
}
viewHandle.Initialize((ulong)size + extraMemNeeded);
return new MemoryMappedView(viewHandle, (long)extraMemNeeded, size, access);
}
public unsafe static MemoryMappedView CreateView(
SafeMemoryMappedFileHandle memMappedFileHandle, MemoryMappedFileAccess access,
long requestedOffset, long requestedSize)
{
// If the requested size is either the default or if it's larger than the capacity
// of the mapped file, reset it to be the capacity set when creating the mapped file.
if (requestedSize == MemoryMappedFile.DefaultSize || requestedSize > memMappedFileHandle._capacity)
{
requestedSize = memMappedFileHandle._capacity;
}
Debug.Assert(requestedSize > 0);
// mmap can only create views that start at a multiple of the page size. As on Windows,
// we hide this restriction form the user by creating larger views than the user requested and hiding the parts
// that the user did not request. extraMemNeeded is the amount of extra memory we allocate before the start of the
// requested view. (mmap may round up the actual length such that it is also page-aligned; we hide that by using
// the right size and not extending the size to be page-aligned.)
ulong nativeSize, extraMemNeeded, nativeOffset;
ValidateSizeAndOffset(
requestedSize, requestedOffset, Interop.libc.sysconf(Interop.libc.SysConfNames._SC_PAGESIZE),
out nativeSize, out extraMemNeeded, out nativeOffset);
bool gotRefOnHandle = false;
try
{
// Determine whether to create the pages as private or as shared; the former is used for copy-on-write.
Interop.libc.MemoryMappedFlags flags = (memMappedFileHandle._access == MemoryMappedFileAccess.CopyOnWrite) ?
Interop.libc.MemoryMappedFlags.MAP_PRIVATE :
Interop.libc.MemoryMappedFlags.MAP_SHARED;
// If we have a file handle, get the file descriptor from it. If the handle is null,
// we'll use an anonymous backing store for the map.
int fd;
if (memMappedFileHandle._fileHandle != null)
{
// Get the file descriptor from the SafeFileHandle
memMappedFileHandle._fileHandle.DangerousAddRef(ref gotRefOnHandle);
Debug.Assert(gotRefOnHandle);
fd = (int)memMappedFileHandle._fileHandle.DangerousGetHandle();
Debug.Assert(fd >= 0);
}
else
{
Debug.Assert(!gotRefOnHandle);
fd = -1;
flags |= Interop.libc.MemoryMappedFlags.MAP_ANONYMOUS;
}
// Nothing to do for options.DelayAllocatePages, since we're only creating the map
// with mmap when creating the view.
// Intersect the permissions from the creation of the MMF and the MMV.
Interop.libc.MemoryMappedProtections prot = GetProtections(memMappedFileHandle._access);
prot &= GetProtections(access);
if (prot == 0)
{
throw new ArgumentOutOfRangeException("access");
}
// Create the map
IntPtr addr = Interop.libc.mmap(
IntPtr.Zero, // don't specify an address; let the system choose one
(IntPtr)nativeSize, // specify the rounded-size we computed so as to page align; size + extraMemNeeded
prot,
flags,
fd, // mmap adds a ref count to the fd, so there's no need to dup it.
(long)nativeOffset); // specify the rounded-offset we computed so as to page align; offset - extraMemNeeded
if ((long)addr < 0)
{
throw Interop.GetExceptionForIoErrno(Marshal.GetLastWin32Error());
}
// Based on the HandleInheritability, try to prevent the memory-mapped region
// from being inherited by a forked process
if (memMappedFileHandle._inheritability == HandleInheritability.None)
{
int adviseResult = Interop.libc.madvise(addr, (IntPtr)nativeSize, Interop.libc.MemoryMappedAdvice.MADV_DONTFORK);
Debug.Assert(adviseResult == 0); // In release, ignore failures from advise; it's just a hint, anyway.
}
// Create and return the view handle
var viewHandle = new SafeMemoryMappedViewHandle(addr, ownsHandle: true);
viewHandle.Initialize(nativeSize);
return new MemoryMappedView(
viewHandle,
(long)extraMemNeeded, // the view points to offset - extraMemNeeded, so we need to shift back by extraMemNeeded
requestedSize, // only allow access to the actual size requested
access);
}
finally
{
if (gotRefOnHandle)
{
memMappedFileHandle._fileHandle.DangerousRelease();
}
}
}
private Win32MemoryMappedFile(FileStream fs, SafeMemoryMappedFileHandle handle, ulong size)
{
Contract.Requires(fs != null && handle != null && !handle.IsInvalid && !handle.IsClosed);
m_mapHandle = handle;
m_file = fs;
m_size = size;
// verify that it fits on 32 bit OS...
if (IntPtr.Size == 4 && size > uint.MaxValue)
{ // won't work with 32-bit pointers
throw new InvalidOperationException("Memory mapped file size is too big to be opened on a 32-bit system.");
}
// verifiy that it will fit in the virtual address space of the process
var totalVirtual = UnsafeNativeMethods.GetTotalVirtualAddressSpaceSize();
if (size > totalVirtual)
{
throw new InvalidOperationException("Memory mapped file size is too big to fit in the current process virtual address space");
}
SafeMemoryMappedViewHandle view = null;
byte* baseAddress = null;
try
{
view = UnsafeNativeMethods.MapViewOfFile(m_mapHandle, UnsafeNativeMethods.FileMapAccess.FileMapRead, 0, 0, new UIntPtr(size));
if (view.IsInvalid) throw Marshal.GetExceptionForHR(Marshal.GetHRForLastWin32Error());
view.Initialize(size);
m_viewHandle = view;
view.AcquirePointer(ref baseAddress);
m_baseAddress = baseAddress;
}
catch
{
if (baseAddress != null) view.ReleasePointer();
if (view != null) view.Dispose();
m_file = null;
m_viewHandle = null;
m_mapHandle = null;
m_baseAddress = null;
throw;
}
}
/*
[SecurityCritical, DllImport("kernel32.dll", SetLastError=true, ExactSpelling=true)]
internal static extern SafeMemoryMappedViewHandle MapViewOfFile(SafeMemoryMappedFileHandle handle, int dwDesiredAccess, uint dwFileOffsetHigh, uint dwFileOffsetLow, UIntPtr dwNumberOfBytesToMap);
[SecurityCritical, DllImport("kernel32.dll", CharSet=CharSet.Auto, SetLastError=true)]
internal static extern SafeMemoryMappedFileHandle OpenFileMapping(int dwDesiredAccess, [MarshalAs(UnmanagedType.Bool)] bool bInheritHandle, string lpName);
[SecurityCritical, DllImport("advapi32.dll", CharSet=CharSet.Unicode, SetLastError=true, ExactSpelling=true)]
internal static extern unsafe PerfCounterSetInstanceStruct* PerfCreateInstance([In] SafePerfProviderHandle hProvider, [In] ref Guid CounterSetGuid, [In] string szInstanceName, [In] uint dwInstance);
[SecurityCritical, DllImport("advapi32.dll", CharSet=CharSet.Unicode, ExactSpelling=true)]
internal static extern unsafe uint PerfDeleteInstance([In] SafePerfProviderHandle hProvider, [In] PerfCounterSetInstanceStruct* InstanceBlock);
[SecurityCritical, DllImport("advapi32.dll", CharSet=CharSet.Unicode, ExactSpelling=true)]
internal static extern unsafe int PerfSetCounterRefValue([In] SafePerfProviderHandle hProvider, [In] PerfCounterSetInstanceStruct* pInstance, [In] int CounterId, [In] void* lpAddr);
[SecurityCritical, DllImport("advapi32.dll", CharSet=CharSet.Unicode, ExactSpelling=true)]
internal static extern unsafe uint PerfSetCounterSetInfo([In] SafePerfProviderHandle hProvider, [In, Out] PerfCounterSetInfoStruct* pTemplate, [In] uint dwTemplateSize);
[SecurityCritical, DllImport("advapi32.dll", CharSet=CharSet.Unicode, ExactSpelling=true)]
internal static extern uint PerfStartProvider([In] ref Guid ProviderGuid, [In] PERFLIBREQUEST ControlCallback, out SafePerfProviderHandle phProvider);
[SecurityCritical, DllImport("advapi32.dll", CharSet=CharSet.Unicode, ExactSpelling=true)]
internal static extern uint PerfStopProvider([In] IntPtr hProvider);
[SecurityCritical, DllImport("kernel32.dll", SetLastError=true)]
internal static extern unsafe int ReadFile(SafePipeHandle handle, byte* bytes, int numBytesToRead, IntPtr numBytesRead_mustBeZero, NativeOverlapped* overlapped);
[SecurityCritical, DllImport("kernel32.dll", SetLastError=true)]
internal static extern unsafe int ReadFile(SafePipeHandle handle, byte* bytes, int numBytesToRead, out int numBytesRead, IntPtr mustBeZero);
[return: MarshalAs(UnmanagedType.Bool)]
[SecurityCritical, ReliabilityContract(Consistency.WillNotCorruptState, Cer.MayFail), DllImport("advapi32.dll", SetLastError=true)]
internal static extern bool RevertToSelf();
*/
internal static SafeMemoryMappedViewHandle MapViewOfFile (SafeMemoryMappedFileHandle handle, int dwDesiredAccess, uint dwFileOffsetHigh, uint dwFileOffsetLow, UIntPtr dwNumberOfBytesToMap)
{
return null;
}
private static Microsoft.Win32.SafeHandles.SafeMemoryMappedFileHandle CreateOrOpenCore(SafeFileHandle fileHandle, string mapName, HandleInheritability inheritability, MemoryMappedFileSecurity memoryMappedFileSecurity, MemoryMappedFileAccess access, MemoryMappedFileOptions options, long capacity)
{
Microsoft.Win32.SafeHandles.SafeMemoryMappedFileHandle handle = null;
object obj2;
Microsoft.Win32.UnsafeNativeMethods.SECURITY_ATTRIBUTES lpAttributes = GetSecAttrs(inheritability, memoryMappedFileSecurity, out obj2);
int dwMaximumSizeLow = (int)(((ulong)capacity) & 0xffffffffL);
int dwMaximumSizeHigh = (int)(capacity >> 0x20);
try
{
int num3 = 14;
int millisecondsTimeout = 0;
while (num3 > 0)
{
handle = Microsoft.Win32.UnsafeNativeMethods.CreateFileMapping(fileHandle, lpAttributes, GetPageAccess(access) | options, dwMaximumSizeHigh, dwMaximumSizeLow, mapName);
int errorCode = Marshal.GetLastWin32Error();
if (!handle.IsInvalid)
{
break;
}
if (errorCode != 5)
{
System.IO.__Error.WinIOError(errorCode, string.Empty);
}
handle.SetHandleAsInvalid();
handle = Microsoft.Win32.UnsafeNativeMethods.OpenFileMapping(GetFileMapAccess(access), (inheritability & HandleInheritability.Inheritable) != HandleInheritability.None, mapName);
int num6 = Marshal.GetLastWin32Error();
if (!handle.IsInvalid)
{
break;
}
if (num6 != 2)
{
System.IO.__Error.WinIOError(num6, string.Empty);
}
num3--;
if (millisecondsTimeout == 0)
{
millisecondsTimeout = 10;
}
else
{
Thread.Sleep(millisecondsTimeout);
millisecondsTimeout *= 2;
}
}
if ((handle == null) || handle.IsInvalid)
{
throw new InvalidOperationException(System.SR.GetString("InvalidOperation_CantCreateFileMapping"));
}
return(handle);
}
finally
{
if (obj2 != null)
{
((GCHandle)obj2).Free();
}
}
return(handle);
}
void Dispose(bool disposeManagedResources)
{
if (this._handle != null && !this._handle.IsClosed)
{
this._handle.Dispose();
this._handle = null;
}
}
internal static extern SafeMemoryMappedViewHandle MapViewOfFileFromApp(
SafeMemoryMappedFileHandle hFileMappingObject,
int DesiredAccess,
long FileOffset,
UIntPtr NumberOfBytesToMap);
internal static SafeMemoryMappedViewHandle MapViewOfFile(SafeMemoryMappedFileHandle hFileMappingObject, FileMapAccess dwDesiredAccess, ulong ddFileOffset, UIntPtr dwNumberofBytesToMap)
{
uint hi = (UInt32)(ddFileOffset / UInt32.MaxValue);
uint lo = (UInt32)(ddFileOffset % UInt32.MaxValue);
return MapViewOfFile(hFileMappingObject, dwDesiredAccess, hi, lo, dwNumberofBytesToMap);
}
public unsafe static MemoryMappedView CreateView(
SafeMemoryMappedFileHandle memMappedFileHandle, MemoryMappedFileAccess access,
long requestedOffset, long requestedSize)
{
if (requestedOffset > memMappedFileHandle._capacity)
{
throw new ArgumentOutOfRangeException("offset");
}
if (requestedSize > MaxProcessAddressSpace)
{
throw new IOException(SR.ArgumentOutOfRange_CapacityLargerThanLogicalAddressSpaceNotAllowed);
}
if (requestedOffset + requestedSize > memMappedFileHandle._capacity)
{
throw new UnauthorizedAccessException();
}
if (memMappedFileHandle.IsClosed)
{
throw new ObjectDisposedException(typeof(MemoryMappedFile).Name);
}
if (requestedSize == MemoryMappedFile.DefaultSize)
{
requestedSize = memMappedFileHandle._capacity - requestedOffset;
}
// mmap can only create views that start at a multiple of the page size. As on Windows,
// we hide this restriction form the user by creating larger views than the user requested and hiding the parts
// that the user did not request. extraMemNeeded is the amount of extra memory we allocate before the start of the
// requested view. (mmap may round up the actual length such that it is also page-aligned; we hide that by using
// the right size and not extending the size to be page-aligned.)
ulong nativeSize;
long extraMemNeeded, nativeOffset;
long pageSize = Interop.Sys.SysConf(Interop.Sys.SysConfName._SC_PAGESIZE);
Debug.Assert(pageSize > 0);
ValidateSizeAndOffset(
requestedSize, requestedOffset, pageSize,
out nativeSize, out extraMemNeeded, out nativeOffset);
// Determine whether to create the pages as private or as shared; the former is used for copy-on-write.
Interop.Sys.MemoryMappedFlags flags =
(memMappedFileHandle._access == MemoryMappedFileAccess.CopyOnWrite || access == MemoryMappedFileAccess.CopyOnWrite) ?
Interop.Sys.MemoryMappedFlags.MAP_PRIVATE :
Interop.Sys.MemoryMappedFlags.MAP_SHARED;
// If we have a file handle, get the file descriptor from it. If the handle is null,
// we'll use an anonymous backing store for the map.
SafeFileHandle fd;
if (memMappedFileHandle._fileStream != null)
{
// Get the file descriptor from the SafeFileHandle
fd = memMappedFileHandle._fileStream.SafeFileHandle;
Debug.Assert(!fd.IsInvalid);
}
else
{
fd = new SafeFileHandle(new IntPtr(-1), false);
flags |= Interop.Sys.MemoryMappedFlags.MAP_ANONYMOUS;
}
// Nothing to do for options.DelayAllocatePages, since we're only creating the map
// with mmap when creating the view.
// Verify that the requested view permissions don't exceed the map's permissions
Interop.Sys.MemoryMappedProtections viewProtForVerification = GetProtections(access, forVerification: true);
Interop.Sys.MemoryMappedProtections mapProtForVerification = GetProtections(memMappedFileHandle._access, forVerification: true);
if ((viewProtForVerification & mapProtForVerification) != viewProtForVerification)
{
throw new UnauthorizedAccessException();
}
// viewProtections is strictly less than mapProtections, so use viewProtections for actually creating the map.
Interop.Sys.MemoryMappedProtections viewProtForCreation = GetProtections(access, forVerification: false);
// Create the map
IntPtr addr = IntPtr.Zero;
if (nativeSize > 0)
{
addr = Interop.Sys.MMap(
IntPtr.Zero, // don't specify an address; let the system choose one
nativeSize, // specify the rounded-size we computed so as to page align; size + extraMemNeeded
viewProtForCreation,
flags,
fd, // mmap adds a ref count to the fd, so there's no need to dup it.
nativeOffset); // specify the rounded-offset we computed so as to page align; offset - extraMemNeeded
}
else
{
// There are some corner cases where the .NET API allows the requested size to be zero, e.g. the caller is
// creating a map at the end of the capacity. We can't pass 0 to mmap, as that'll fail with EINVAL, nor can
// we create a map that extends beyond the end of the underlying file, as that'll fail on some platforms at the
// time of the map's creation. Instead, since there's no data to be read/written, it doesn't actually matter
// what backs the view, so we just create an anonymous mapping.
addr = Interop.Sys.MMap(
IntPtr.Zero,
1, // any length that's greater than zero will suffice
viewProtForCreation,
flags | Interop.Sys.MemoryMappedFlags.MAP_ANONYMOUS,
new SafeFileHandle(new IntPtr(-1), false), // ignore the actual fd even if there was one
0);
requestedSize = 0;
extraMemNeeded = 0;
}
if (addr == IntPtr.Zero) // note that shim uses null pointer, not non-null MAP_FAILED sentinel
{
throw Interop.GetExceptionForIoErrno(Interop.Sys.GetLastErrorInfo());
}
// Based on the HandleInheritability, try to prevent the memory-mapped region
// from being inherited by a forked process
if (memMappedFileHandle._inheritability == HandleInheritability.None)
{
DisableForkingIfPossible(addr, nativeSize);
}
// Create and return the view handle
var viewHandle = new SafeMemoryMappedViewHandle(addr, ownsHandle: true);
viewHandle.Initialize((ulong)nativeSize);
return new MemoryMappedView(
viewHandle,
extraMemNeeded, // the view points to offset - extraMemNeeded, so we need to shift back by extraMemNeeded
requestedSize, // only allow access to the actual size requested
access);
}
public static extern SafeMemoryMappedViewHandle MapViewOfFile(SafeMemoryMappedFileHandle handle, FileMapAccess dwDesiredAccess, uint dwFileOffsetHigh, uint dwFileOffsetLow, UIntPtr dwNumberOfBytesToMap);
internal static SafeMemoryMappedFileHandle CreateFileMapping(SafeFileHandle hFile, SECURITY_ATTRIBUTES lpAttributes, int fProtect, int dwMaximumSizeHigh, int dwMaximumSizeLow, string lpName)
{
var handle = new SafeMemoryMappedFileHandle(hFile.DangerousGetHandle (), false);
return handle;
}
internal unsafe static MemoryMappedView CreateView(SafeMemoryMappedFileHandle memMappedFileHandle,
MemoryMappedFileAccess access, Int64 offset, Int64 size) {
// MapViewOfFile can only create views that start at a multiple of the system memory allocation
// granularity. We decided to hide this restriction form the user by creating larger views than the
// user requested and hiding the parts that the user did not request. extraMemNeeded is the amount of
// extra memory we allocate before the start of the requested view. MapViewOfFile will also round the
// capacity of the view to the nearest multiple of the system page size. Once again, we hide this
// from the user by preventing them from writing to any memory that they did not request.
ulong extraMemNeeded = (ulong)offset % (ulong)MemoryMappedFile.GetSystemPageAllocationGranularity();
// newOffset takes into account the fact that we have some extra memory allocated before the requested view
ulong newOffset = (ulong)offset - extraMemNeeded;
Debug.Assert(newOffset >= 0, "newOffset = (offset - extraMemNeeded) < 0");
// determine size to pass to MapViewOfFile
ulong nativeSize;
if (size != MemoryMappedFile.DefaultSize) {
nativeSize = (ulong)size + (ulong)extraMemNeeded;
}
else {
nativeSize = 0;
}
if (IntPtr.Size == 4 && nativeSize > UInt32.MaxValue) {
throw new ArgumentOutOfRangeException("size", SR.GetString(SR.ArgumentOutOfRange_CapacityLargerThanLogicalAddressSpaceNotAllowed));
}
// if request is >= than total virtual, then MapViewOfFile will fail with meaningless error message
// "the parameter is incorrect"; this provides better error message in advance
UnsafeNativeMethods.MEMORYSTATUSEX memStatus = new UnsafeNativeMethods.MEMORYSTATUSEX();
bool result = UnsafeNativeMethods.GlobalMemoryStatusEx(memStatus);
ulong totalVirtual = memStatus.ullTotalVirtual;
if (nativeSize >= totalVirtual) {
throw new IOException(SR.GetString(SR.IO_NotEnoughMemory));
}
// split the Int64 into two ints
uint offsetLow = (uint)(newOffset & 0x00000000FFFFFFFFL);
uint offsetHigh = (uint)(newOffset >> 32);
// create the view
SafeMemoryMappedViewHandle viewHandle = UnsafeNativeMethods.MapViewOfFile(memMappedFileHandle,
MemoryMappedFile.GetFileMapAccess(access), offsetHigh, offsetLow, new UIntPtr(nativeSize));
if (viewHandle.IsInvalid) {
__Error.WinIOError(Marshal.GetLastWin32Error(), String.Empty);
}
// Query the view for its size and allocation type
UnsafeNativeMethods.MEMORY_BASIC_INFORMATION viewInfo = new UnsafeNativeMethods.MEMORY_BASIC_INFORMATION();
UnsafeNativeMethods.VirtualQuery(viewHandle, ref viewInfo, (IntPtr)Marshal.SizeOf(viewInfo));
ulong viewSize = (ulong)viewInfo.RegionSize;
// allocate the pages if we were using the MemoryMappedFileOptions.DelayAllocatePages option
if ((viewInfo.State & UnsafeNativeMethods.MEM_RESERVE) != 0) {
IntPtr tempHandle = UnsafeNativeMethods.VirtualAlloc(viewHandle, (UIntPtr)viewSize, UnsafeNativeMethods.MEM_COMMIT,
MemoryMappedFile.GetPageAccess(access));
int lastError = Marshal.GetLastWin32Error();
if (viewHandle.IsInvalid) {
__Error.WinIOError(lastError, String.Empty);
}
}
// if the user specified DefaultSize as the size, we need to get the actual size
if (size == MemoryMappedFile.DefaultSize) {
size = (Int64)(viewSize - extraMemNeeded);
}
else {
Debug.Assert(viewSize >= (ulong)size, "viewSize < size");
}
viewHandle.Initialize((ulong)size + extraMemNeeded);
MemoryMappedView mmv = new MemoryMappedView(viewHandle, (long)extraMemNeeded, size, access);
return mmv;
}
public static extern SafeMemoryMappedViewHandle MapViewOfFile(
SafeMemoryMappedFileHandle hFileMappingObject,
Kernel32.FileMapAccess dwDesiredAccess,
uint dwFileOffsetHigh,
uint dwFileOffsetLow,
IntPtr dwNumberOfBytesToMap);
