Ring3层 UNICODE_STRING

今天写驱动用到UNICODE_STRING，就在Ring3层抠了一些源代码，学习一下，不多说了上代码了

 #pragma once

 #include <windows.h>
 #include <iostream>
 using namespace std;
 #define BUFFER_SIZE 0x400
 typedef struct _UNICODE_STRING
 {
     USHORT Length;
     USHORT MaximumLength;
     PWCHAR Buffer;
 }UNICODE_STRING,*PUNICODE_STRING;

 /************************************************************************/
 /* 初始化                                                               */
 /************************************************************************/
 void Sub_1();
 VOID
 RtlInitUnicodeString(
     OUT PUNICODE_STRING DestinationString,
     IN PCWSTR SourceString OPTIONAL);//微软源代码

 void Sub_2();
 void Sub_3();
 void Sub_4();
 VOID
 RtlCopyUnicodeString(
     OUT PUNICODE_STRING DestinationString,
     IN PUNICODE_STRING SourceString OPTIONAL);//微软源代码
 VOID
 RtlFreeUnicodeString(
     IN OUT PUNICODE_STRING UnicodeString);     //微软源代码

 #include "UnicodeString(User).h"
 int main()
 {
     Sub_1();
     Sub_2();
     Sub_3();
     Sub_4();
     printf("Input AnyKey To Exit\r\n");
     getchar();

     return ;
 }

 void Sub_1()
 {
     //常量指针直接灌上去
     UNICODE_STRING v1;
     RtlInitUnicodeString(&v1, L"HelloWorld");
     printf("%Z\r\n", &v1);
 }
 //Windows源代码
 VOID
 RtlInitUnicodeString(
     OUT PUNICODE_STRING DestinationString,
     IN PCWSTR SourceString OPTIONAL)
 {
     USHORT Length = ;
      DestinationString->Length = ;
      DestinationString->Buffer = (PWCHAR)SourceString;

      if (SourceString!=NULL)
      {
          while (*SourceString++)//源地址头
          {
              Length += sizeof(*SourceString);
              DestinationString->Length = Length;
              DestinationString->MaximumLength = Length + sizeof(UNICODE_NULL);
          }
      }
      else
      {
          DestinationString->Length = ;
          DestinationString->MaximumLength = ;
      }

 }
 void Sub_2()
 {
     //栈区内存通过缓存区灌上去
     UNICODE_STRING v1;
     WCHAR BufferData[] = L"HelloWorld";
     v1.Buffer = BufferData;
     v1.Length = wcslen(BufferData) * sizeof(WCHAR);
     v1.MaximumLength = (wcslen(BufferData) + ) * sizeof(WCHAR);
     printf("%Z\r\n", &v1);
 }
 void Sub_3()
 {
     //堆区内存通过动态申请
     UNICODE_STRING v1;
     WCHAR BufferData[] = L"HelloWorld";

     v1.Length = wcslen(BufferData) * sizeof(WCHAR);
     v1.MaximumLength = (wcslen(BufferData) + ) * sizeof(WCHAR);
     v1.Buffer = (WCHAR*)malloc(v1.MaximumLength);
     RtlZeroMemory(v1.Buffer, v1.MaximumLength);
     RtlCopyMemory(v1.Buffer, BufferData, v1.Length);

     printf("%Z\r\n", &v1);
     if (v1.Buffer != NULL)
     {
         free(v1.Buffer);
         v1.Buffer = NULL;
         v1.Length = v1.MaximumLength = ;
     }
 }

 void Sub_4()
 {

     UNICODE_STRING SourceString;
     RtlInitUnicodeString(&SourceString, L"HelloWorld");
     UNICODE_STRING DestinationString = {  };

     DestinationString.Buffer = (PWSTR)malloc(BUFFER_SIZE);
     DestinationString.MaximumLength = BUFFER_SIZE;

     RtlCopyUnicodeString(&DestinationString, &SourceString);

     printf("SourceString:%wZ\n", &SourceString);
     printf("DestinationString:%wZ\n", &DestinationString);

     RtlFreeUnicodeString(&DestinationString);
 }

 VOID
 RtlCopyUnicodeString(
     OUT PUNICODE_STRING DestinationString,
     IN PUNICODE_STRING SourceString OPTIONAL
 )
 {
     WCHAR *v1, *v2;
     ULONG SourceStringLength = ;
     if (SourceString != NULL)
     {

         v1 = DestinationString->Buffer;
         v2 = SourceString->Buffer;
         SourceStringLength = SourceString->Length;
         if ((USHORT)SourceStringLength > DestinationString->MaximumLength) //这个UHORT转换挺重要不然gg
         {
             SourceStringLength = DestinationString->MaximumLength;//一个是目标长度小于源目标
         }

         DestinationString->Length = (USHORT)SourceStringLength;

         RtlCopyMemory(v1, v2, SourceStringLength);

         if (DestinationString->Length < DestinationString->MaximumLength)
         {
             v1[SourceStringLength / sizeof(WCHAR)] = UNICODE_NULL;//清空操作
             //或者v2[SourceStringLength] = UNICODE_NULL;//清空操作
         }
     }
     else
     {
         DestinationString->Length = ;
         DestinationString->MaximumLength = ;
     }
     return;
 }

 VOID
 RtlFreeUnicodeString(
     IN OUT PUNICODE_STRING UnicodeString
     )
 {

     if (UnicodeString->Buffer)
     {
         free(UnicodeString->Buffer);
         memset( UnicodeString, , sizeof( *UnicodeString ) );
     }
 }