mcs/class/referencesource/System.Data/System/Data/Common/SafeNativeMethods.cs

   1 //------------------------------------------------------------------------------
   2 // <copyright file="SafeNativeMethods.cs" company="Microsoft">
   3 //      Copyright (c) Microsoft Corporation.  All rights reserved.
   4 // </copyright>
   5 // <owner current="true" primary="true">Microsoft</owner>
   6 // <owner current="true" primary="false">Microsoft</owner>
   7 // <owner current="true" primary="false">Microsoft</owner>
   8 //------------------------------------------------------------------------------
   9
  10 using System;
  11 using System.Runtime.CompilerServices;
  12 using System.Runtime.InteropServices;
  13 using System.Security;
  14 using System.Security.Permissions;
  15 using System.Text;
  16 using System.Threading;
  17 using System.Runtime.ConstrainedExecution;
  18 using System.Runtime.Versioning;
  19
  20 namespace System.Data.Common {
  21
  22     [SuppressUnmanagedCodeSecurityAttribute()]
  23     internal static class SafeNativeMethods {
  24
  25         [DllImport(ExternDll.Ole32, SetLastError=false)]
  26         [ReliabilityContract(Consistency.WillNotCorruptState, Cer.MayFail)]
  27         [ResourceExposure(ResourceScope.None)]
  28         static internal extern IntPtr CoTaskMemAlloc(IntPtr cb);
  29
  30         [DllImport(ExternDll.Ole32, SetLastError=false)]
  31         [ReliabilityContract(Consistency.WillNotCorruptState, Cer.Success)]
  32         [ResourceExposure(ResourceScope.None)]
  33         static internal extern void CoTaskMemFree(IntPtr handle);
  34
  35         [DllImport(ExternDll.Kernel32, CharSet=CharSet.Unicode, PreserveSig=true)]
  36         [ResourceExposure(ResourceScope.None)]
  37         static internal extern int GetUserDefaultLCID();
  38
  39         [DllImport(ExternDll.Kernel32, PreserveSig=true)]
  40         [ReliabilityContract(Consistency.WillNotCorruptState, Cer.Success)]
  41         [ResourceExposure(ResourceScope.None)]
  42         static internal extern void ZeroMemory(IntPtr dest, IntPtr length);
  43
  44         // <WARNING>
  45         // Using the int versions of the Increment() and Decrement() methods is correct.
  46         // Please check \fx\src\Data\System\Data\Odbc\OdbcHandle.cs for the memory layout.
  47         // </WARNING>
  48
  49         // <NDPWHIDBEY 18133>
  50         // The following casting operations require these three methods to be unsafe.  This is
  51         // a workaround for this issue to meet the M1 exit criteria.  We need to revisit this in M2.
  52
  53         [ReliabilityContract(Consistency.WillNotCorruptState, Cer.MayFail)]
  54         static internal unsafe IntPtr InterlockedExchangePointer(
  55                 IntPtr lpAddress,
  56                 IntPtr lpValue)
  57         {
  58             IntPtr  previousPtr;
  59             IntPtr  actualPtr = *(IntPtr *)lpAddress.ToPointer();
  60
  61             do {
  62                 previousPtr = actualPtr;
  63                 actualPtr   = Interlocked.CompareExchange(ref *(IntPtr *)lpAddress.ToPointer(), lpValue, previousPtr);
  64             }
  65             while (actualPtr != previousPtr);
  66
  67             return actualPtr;
  68         }
  69
  70         // http://msdn.microsoft.com/library/default.asp?url=/library/en-us/sysinfo/base/getcomputernameex.asp
  71         [DllImport(ExternDll.Kernel32, CharSet = CharSet.Unicode, EntryPoint="GetComputerNameExW", SetLastError=true)]
  72         [ResourceExposure(ResourceScope.None)]
  73         static internal extern int GetComputerNameEx(int nameType, StringBuilder nameBuffer, ref int bufferSize);
  74
  75         [DllImport(ExternDll.Kernel32, CharSet=System.Runtime.InteropServices.CharSet.Auto)]
  76         [ResourceExposure(ResourceScope.Process)]
  77         static internal extern int GetCurrentProcessId();
  78
  79         [DllImport(ExternDll.Kernel32, CharSet=CharSet.Auto, BestFitMapping=false, ThrowOnUnmappableChar=true)]
  80 //        [DllImport(ExternDll.Kernel32, CharSet=CharSet.Auto)]
  81         [ResourceExposure(ResourceScope.Process)]
  82         static internal extern IntPtr GetModuleHandle([MarshalAs(UnmanagedType.LPTStr), In] string moduleName/*lpctstr*/);
  83
  84         [DllImport(ExternDll.Kernel32, CharSet = CharSet.Ansi, BestFitMapping = false, ThrowOnUnmappableChar = true, SetLastError = true)]
  85 //        [DllImport(ExternDll.Kernel32, CharSet=CharSet.Ansi)]
  86         [ResourceExposure(ResourceScope.None)]
  87         static internal extern IntPtr GetProcAddress(IntPtr HModule, [MarshalAs(UnmanagedType.LPStr), In] string funcName/*lpcstr*/);
  88
  89         [DllImport(ExternDll.Kernel32, SetLastError=true)]
  90         [ReliabilityContract(Consistency.WillNotCorruptState, Cer.MayFail)]
  91         [ResourceExposure(ResourceScope.None)]
  92         static internal extern IntPtr LocalAlloc(int flags, IntPtr countOfBytes);
  93
  94         [DllImport(ExternDll.Kernel32, SetLastError=true)]
  95         [ReliabilityContract(Consistency.WillNotCorruptState, Cer.Success)]
  96         [ResourceExposure(ResourceScope.None)]
  97         static internal extern IntPtr LocalFree(IntPtr handle);
  98
  99         [DllImport(ExternDll.Oleaut32, CharSet=CharSet.Unicode)]
 100         [ReliabilityContract(Consistency.WillNotCorruptState, Cer.MayFail)]
 101         [ResourceExposure(ResourceScope.None)]
 102         internal static extern IntPtr SysAllocStringLen(String src, int len);  // BSTR
 103
 104         [DllImport(ExternDll.Oleaut32)]
 105         [ReliabilityContract(Consistency.WillNotCorruptState, Cer.Success)]
 106         [ResourceExposure(ResourceScope.None)]
 107         internal static extern void SysFreeString(IntPtr bstr);
 108
 109         // only using this to clear existing error info with null
 110         [DllImport(ExternDll.Oleaut32, CharSet=CharSet.Unicode, PreserveSig=false)]
 111         // TLS values are preserved between threads, need to check that we use this API to clear the error state only.
 112         [ResourceExposure(ResourceScope.Process)]
 113         static private extern void SetErrorInfo(Int32 dwReserved, IntPtr pIErrorInfo);
 114
 115         [DllImport(ExternDll.Kernel32, SetLastError=true)]
 116         [ReliabilityContract(Consistency.WillNotCorruptState, Cer.MayFail)]
 117         [ResourceExposure(ResourceScope.Machine)]
 118         static internal extern int ReleaseSemaphore(IntPtr handle, int releaseCount, IntPtr previousCount);
 119
 120         [DllImport(ExternDll.Kernel32, SetLastError=true)]
 121         [ReliabilityContract(Consistency.WillNotCorruptState, Cer.MayFail)]
 122         [ResourceExposure(ResourceScope.None)]
 123         static internal extern int WaitForMultipleObjectsEx(uint nCount, IntPtr lpHandles, bool bWaitAll, uint dwMilliseconds, bool bAlertable);
 124
 125         [DllImport(ExternDll.Kernel32/*, SetLastError=true*/)]
 126         [ReliabilityContract(Consistency.WillNotCorruptState, Cer.MayFail)]
 127         [ResourceExposure(ResourceScope.None)]
 128         static internal extern int WaitForSingleObjectEx(IntPtr lpHandles, uint dwMilliseconds, bool bAlertable);
 129
 130         [DllImport(ExternDll.Ole32, PreserveSig=false)]
 131         [ReliabilityContract(Consistency.WillNotCorruptState, Cer.Success)]
 132         [ResourceExposure(ResourceScope.None)]
 133         static internal extern void PropVariantClear(IntPtr pObject);
 134
 135         [DllImport(ExternDll.Oleaut32, PreserveSig=false)]
 136         [ReliabilityContract(Consistency.WillNotCorruptState, Cer.Success)]
 137         [ResourceExposure(ResourceScope.None)]
 138         static internal extern void VariantClear(IntPtr pObject);
 139
 140         sealed internal class Wrapper {
 141
 142             private Wrapper() { }
 143
 144             // SxS: clearing error information is considered safe
 145             [ResourceExposure(ResourceScope.None)]
 146             [ResourceConsumption(ResourceScope.Process, ResourceScope.Process)]
 147             static internal void ClearErrorInfo() { // MDAC 68199
 148                 SafeNativeMethods.SetErrorInfo(0, ADP.PtrZero);
 149             }
 150         }
 151
 152
 153     }
 154 }