Question

我需要在C＃中读取消息表资源。

我基本上试图将此问题的答案中的代码移植到C＃：Listing message IDs and symbolic names stored in a resource-only library (DLL) using Win32 API

我的问题是我无法正确编组MESSAGE_RESOURCE_DATA和MESSAGE_RESOURCE_BLOCK结构，这些结构的定义如下（<winnt.h>中）：

typedef struct _MESSAGE_RESOURCE_BLOCK {
    DWORD LowId;
    DWORD HighId;
    DWORD OffsetToEntries;
} MESSAGE_RESOURCE_BLOCK, *PMESSAGE_RESOURCE_BLOCK;

typedef struct _MESSAGE_RESOURCE_DATA {
    DWORD NumberOfBlocks;
    MESSAGE_RESOURCE_BLOCK Blocks[ 1 ];
} MESSAGE_RESOURCE_DATA, *PMESSAGE_RESOURCE_DATA;

在MESSAGE_RESOURCE_DATA中，NumberOfBlocks是MESSAGE_RESOURCE_BLOCK数组中Blocks条目的数量（即使它被声明为具有单个元素的数组）。

由于我不知道在编译时数组的大小，我试图编组结构声明Blocks作为指针，然后像这样使用Marshal.PtrToStructure：

using System;
using System.Runtime.InteropServices;

[StructLayout(LayoutKind.Sequential)]
struct MESSAGE_RESOURCE_BLOCK {
    public IntPtr LowId;
    public IntPtr HighId;
    public IntPtr OffsetToEntries;
}

[StructLayout(LayoutKind.Sequential)]
struct MESSAGE_RESOURCE_DATA {
    public IntPtr NumberOfBlocks;
    public IntPtr Blocks;
}

class Program {

    [DllImport("kernel32.dll", SetLastError = true)]
    static extern IntPtr LoadLibrary(string fileName);

    [DllImport("kernel32.dll", SetLastError = true)]
    static extern IntPtr FindResource(IntPtr hModule, int lpID, int lpType);

    [DllImport("kernel32.dll", SetLastError = true)]
    public static extern IntPtr LoadResource(IntPtr hModule, IntPtr hResInfo);

    [DllImport("kernel32.dll")]
    public static extern IntPtr LockResource(IntPtr hResData);

    static void Main(string[] args) {
        const int RT_MESSAGETABLE = 11;
        IntPtr hModule = LoadLibrary(@"C:\WINDOWS\system32\msobjs.dll");
        IntPtr msgTableInfo = FindResource(hModule, 1, RT_MESSAGETABLE);
        IntPtr msgTable = LoadResource(hModule, msgTableInfo);
        var data = Marshal.PtrToStructure<MESSAGE_RESOURCE_DATA>(LockResource(msgTable));
        int blockSize = Marshal.SizeOf<MESSAGE_RESOURCE_BLOCK>();
        for (int i = 0; i < data.NumberOfBlocks.ToInt32(); i++) {
            IntPtr blockPtr = IntPtr.Add(data.Blocks, blockSize * i);
            // the following line causes an access violation
            var block = Marshal.PtrToStructure<MESSAGE_RESOURCE_BLOCK>(blockPtr);
        }
    }
}

然而，这不起作用，我收到了访问冲突错误。

我如何编组这样的结构？

Answer 1

你并不接近，这些结构不包含IntPtr。 DWORD是一个32位整数。资源格式中使用的可变长度结构在C＃中非常笨拙，没有合适的方式来声明它们。最好的办法是使用Marshal.ReadXxx（）来读取字段。

唯一仍然有用的结构声明是：

[StructLayout(LayoutKind.Sequential)]
struct MESSAGE_RESOURCE_BLOCK {
    public int LowId;
    public int HighId;
    public int OffsetToEntries;
}

然后你就这样把它搞砸了：

static void Main(string[] args) {
    const int RT_MESSAGETABLE = 11;
    IntPtr hModule = LoadLibrary(@"C:\WINDOWS\system32\msobjs.dll");
    IntPtr msgTableInfo = FindResource(hModule, 1, RT_MESSAGETABLE);
    IntPtr msgTable = LoadResource(hModule, msgTableInfo);
    IntPtr memTable = LockResource(msgTable);

    int numberOfBlocks = Marshal.ReadInt32(memTable);
    IntPtr blockPtr = IntPtr.Add(memTable, 4);
    int blockSize = Marshal.SizeOf<MESSAGE_RESOURCE_BLOCK>();

    for (int i = 0; i < numberOfBlocks; i++) {
        var block = Marshal.PtrToStructure<MESSAGE_RESOURCE_BLOCK>(blockPtr);
        IntPtr entryPtr = IntPtr.Add(memTable, block.OffsetToEntries);

        for (int id = block.LowId; id <= block.HighId; id++) {
            var length = Marshal.ReadInt16(entryPtr);
            var flags = Marshal.ReadInt16(entryPtr, 2);
            var textPtr = IntPtr.Add(entryPtr, 4);
            var text = "Bad flags??";
            if (flags == 0) {
                text = Marshal.PtrToStringAnsi(textPtr);
            }
            else if (flags == 1) {
                text = Marshal.PtrToStringUni(textPtr);
            }
            text = text.Replace("\r\n", "");
            Console.WriteLine("{0} : {1}", id, text);
            entryPtr = IntPtr.Add(entryPtr, length);
        }
        blockPtr = IntPtr.Add(blockPtr, blockSize);
    }
}

32位和64位模式下的输出：

279 : Undefined Access (no effect) Bit 7
1536 : Unused message ID
1537 : DELETE
1538 : READ_CONTROL
1539 : WRITE_DAC
1540 : WRITE_OWNER
1541 : SYNCHRONIZE
1542 : ACCESS_SYS_SEC
1543 : MAX_ALLOWED
1552 : Unknown specific access (bit 0)
1553 : Unknown specific access (bit 1)
1554 : Unknown specific access (bit 2)
1555 : Unknown specific access (bit 3)
1556 : Unknown specific access (bit 4)
1557 : Unknown specific access (bit 5)
...etc...

请记住，当您使用抖动强制在32位模式下运行程序时，您将不会读取您认为的文件。文件系统重定向器将让您读取C：\ WINDOWS \ SysWow64 \ msobjs.dll。

对消息表资源进行封送

1 个答案: