我想做个虚拟驱动器,很底层的问题,不是FileDisk,类似Subst

我不是要像FileDisk一样,在硬盘中写一个文件做映射,而是要您Windows自带的Subst命令一样,把一个文件夹虚拟成另外的样子,不需要在硬盘中建立专用虚拟文件的,大家帮我出出主义吧,类似Subst的文件夹虚拟和重映射,但比Subst更为复杂的是,我的需求是把多个物理的文件或文件夹"拼"在一个虚拟文件夹下,所以DefineDosDevice是没办法做到的,是不是得自己写驱动啊?应该怎么实现,有没有类似的代码下载???


[编辑 -  6/10/04 by  redbirdli]

我不是要像FileDisk一样,在硬盘中写一个文件做映射,而是要您Windows自带的Subst命令一样,把一个文件夹虚拟成另外的样子,不需要在硬盘中建立专用虚拟文件的,大家帮我出出主义吧,类似Subst的文件夹虚拟和重映射,应该怎么实现,有没有类似的代码下载

可以用创建符号链接（Symbol Link）来实现Subst的功能。
Driver里面可以用IoCreateSymbolicLink；
如果是应用程序，可用DefineDosDevice（这个我没试过）。

查了一下，发现MSDN中有DefineDosDevice的例子。

/*
DLEDIT  -- Drive Letter Assignment Editor

Platforms:
   This program requires Windows 2000 or later.

Command-line syntax:
   DLEDIT <drive letter> <NT device name>      -- Adds a drive letter
   DLEDIT -r <drive letter>                    -- Removes a drive letter

Command-line examples:

   If E: refers to the CD-ROM drive, use the following commands to
   make F: point to the CD-ROM drive instead.

   DLEDIT -r E:\
   DLEDIT F:\ \Device\CdRom0

*****************************************************************
WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING  

   This program will change drive letter assignments, and the    
   changes persist through reboots. Do not remove drive letters  
   of your hard disks if you do not have this program on floppy  
   disk or you might not be able to access your hard disks again!
*****************************************************************
*/

#define _WIN32_WINNT 0x0500

#include <windows.h>
#include <stdio.h>

#if defined (DEBUG)
   static void DebugPrint (LPCSTR pszMsg, DWORD dwErr);
   #define DEBUG_PRINT(pszMsg, dwErr) DebugPrint(pszMsg, dwErr)
#else
   #define DEBUG_PRINT(pszMsg, dwErr) NULL
#endif

#pragma warning (disable : 4800)

void PrintHelp (LPCSTR pszAppName);

/*--------------------------------------------------------------------
The main function is the main routine. It parses the command-line
arguments and either removes or adds a drive letter.

Parameters
   argc
      Count of the command-line arguments
   argv
      Array of pointers to the individual command-line arguments

--------------------------------------------------------------------*/
void main (int argc, char **argv)
{
   char * pszDriveLetter,
        * pszNTDevice,
        * pszOptions;

   char szUniqueVolumeName[MAX_PATH];
   char szDriveLetterAndSlash[4];
   char szDriveLetter[3];

   bool  fRemoveDriveLetter;
   bool  fResult;

   if (argc != 3)
   {
      PrintHelp(argv[0]);
      return;
   }

   // Use the command line to see if user wants to add or remove the
   // drive letter. Do this by looking for the -r option.

   fRemoveDriveLetter = !lstrcmpi (argv[1], "-r");

   if (fRemoveDriveLetter)
   {
      // User wants to remove the drive letter. Command line should
      // be: dl -r <drive letter>

      pszOptions       = argv[1];
      pszDriveLetter   = argv[2];
      pszNTDevice      = NULL;
   }
   else
   {
      // User wants to add a drive letter. Command line should be:
      // dl <drive letter> <NT device name>

      pszOptions       = NULL;
      pszDriveLetter   = argv[1];
      pszNTDevice      = argv[2];
   }

   // GetVolumeNameForVolumeMountPoint, SetVolumeMountPoint, and
   // DeleteVolumeMountPoint require drive letters to have a trailing
   // backslash. However, DefineDosDevice requires that the trailing
   // backslash be absent. So, we'll use:
   //
   //    szDriveLetterAndSlash     for the mount point APIs
   //    szDriveLetter             for DefineDosDevice
   //
   // This way, we can accept command lines that use a: or a:\
   // for drive letters without writing back to the original command-
   // line argument.

   szDriveLetter[0] = pszDriveLetter[0];
   szDriveLetter[1] = ':';
   szDriveLetter[2] = '\0';

   szDriveLetterAndSlash[0] = pszDriveLetter[0];
   szDriveLetterAndSlash[1] = ':';
   szDriveLetterAndSlash[2] = '\\';
   szDriveLetterAndSlash[3] = '\0';

   // Now add or remove the drive letter.

   if (fRemoveDriveLetter)
   {
      fResult = DeleteVolumeMountPoint (szDriveLetterAndSlash);

      if (!fResult)
         printf("error %lu: couldn't remove %s\n",
                GetLastError(), szDriveLetterAndSlash);
   }
   else
   {
      // To add a drive letter that persists through reboots, use
      // SetVolumeMountPoint. This requires the unique volume name of
      // the device to which the new drive letter will refer. To get
      // the unique volume name, use GetVolumeNameForVolumeMountPoint;
      // it requires the drive letter to already exist. So, we first
      // define the drive letter as a symbolic link to the device
      // name. After we have the unique volume name the new drive
      // letter will point to, we must delete the symbolic link
      // because the mount manager allows only one reference to a
      // device at a time (the new one to be added).

      fResult = DefineDosDevice (DDD_RAW_TARGET_PATH, szDriveLetter,
                                 pszNTDevice);

      if (fResult)
      {
          // If GetVolumeNameForVolumeMountPoint fails, then
          // SetVolumeMountPoint will also fail. However, we must call
          // DefineDosDevice to remove the temporary symbolic link.
          // Therefore, set szUniqueVolume to a known empty string.

         if (!GetVolumeNameForVolumeMountPoint (szDriveLetterAndSlash,
                  szUniqueVolumeName,
                  MAX_PATH))
         {
            DEBUG_PRINT("GetVolumeNameForVolumeMountPoint failed",
                        GetLastError());
            szUniqueVolumeName[0] = '\0';
         }

         fResult = DefineDosDevice (
                      DDD_RAW_TARGET_PATH|DDD_REMOVE_DEFINITION|
                      DDD_EXACT_MATCH_ON_REMOVE, szDriveLetter,
                      pszNTDevice);

         if (!fResult)
            DEBUG_PRINT("DefineDosDevice failed", GetLastError());

         fResult = SetVolumeMountPoint (szDriveLetterAndSlash,
                        szUniqueVolumeName);

         if (!fResult)
            printf ("error %lu: could not add %s\n", GetLastError(),
                    szDriveLetterAndSlash);
      }
   }
}

/*-------------------------------------------------------------------
The PrintHelp function prints the command-line usage help.

Parameters
   pszAppName
      The name of the executable. Used in displaying the help.

-------------------------------------------------------------------*/
void PrintHelp (LPCSTR pszAppName)
{
   printf("Adds/removes a drive letter assignment for a device.\n\n");
   printf("Usage: %s <Drive> <Device name>   add a drive letter\n", pszAppName);
   printf("       %s -r <Drive>              remove a drive letter\n\n", pszAppName);
   printf("Example: %s e:\\ \\Device\\CdRom0\n", pszAppName);
   printf("         %s -r e:\\\n", pszAppName);
}

#if defined (DEBUG)
/*--------------------------------------------------------------------
The DebugPrint function prints a string to STDOUT.

Parameters
   pszMsg
      The string to be printed to STDOUT.
   dwErr
      The error code; usually obtained from GetLastError. If dwErr is
      zero, no error code is added to the error string. If dwErr is
      nonzero, the error code will be printed in the error string.
--------------------------------------------------------------------*/
void DebugPrint (LPCSTR pszMsg, DWORD dwErr)
{
   if (dwErr)
      printf("%s: %lu\n", pszMsg, dwErr);
   else
      printf("%s\n", pszMsg);
}
#endif

When building this sample program, use the following makefile.

APPVER = 5.0
TARGETOS = WINNT

!include <win32.mak>

PROJ = DLEDIT

all: $(PROJ).exe

PROJ_OBJS = dledit.obj

.cpp.obj:
    $(cc) $(cdebug) $(cflags) $(cvars) $<

$(PROJ).exe: $(PROJ_OBJS)
    $(link) $(ldebug) $(conlflags)\
    $(PROJ_OBJS) \
    -out:$(PROJ).exe \
    $(conlibs)

clean:
    del *.bak
    del *.opt
    del *.pdb
    del *.obj

cleaner: clean
    del *.exe

一次居然贴不完！ :(

   szDriveLetterAndSlash[0] = pszDriveLetter[0];
   szDriveLetterAndSlash[1] = ':';
   szDriveLetterAndSlash[2] = '\\';
   szDriveLetterAndSlash[3] = '\0';

   // Now add or remove the drive letter.

   if (fRemoveDriveLetter)
   {
      fResult = DeleteVolumeMountPoint (szDriveLetterAndSlash);

      if (!fResult)
         printf("error %lu: couldn't remove %s\n",
                GetLastError(), szDriveLetterAndSlash);
   }
   else
   {
      // To add a drive letter that persists through reboots, use
      // SetVolumeMountPoint. This requires the unique volume name of
      // the device to which the new drive letter will refer. To get
      // the unique volume name, use GetVolumeNameForVolumeMountPoint;
      // it requires the drive letter to already exist. So, we first
      // define the drive letter as a symbolic link to the device
      // name. After we have the unique volume name the new drive
      // letter will point to, we must delete the symbolic link
      // because the mount manager allows only one reference to a
      // device at a time (the new one to be added).

      fResult = DefineDosDevice (DDD_RAW_TARGET_PATH, szDriveLetter,
                                 pszNTDevice);

      if (fResult)
      {
          // If GetVolumeNameForVolumeMountPoint fails, then
          // SetVolumeMountPoint will also fail. However, we must call
          // DefineDosDevice to remove the temporary symbolic link.
          // Therefore, set szUniqueVolume to a known empty string.

         if (!GetVolumeNameForVolumeMountPoint (szDriveLetterAndSlash,
                  szUniqueVolumeName,
                  MAX_PATH))
         {
            DEBUG_PRINT("GetVolumeNameForVolumeMountPoint failed",
                        GetLastError());
            szUniqueVolumeName[0] = '\0';
         }

         fResult = DefineDosDevice (
                      DDD_RAW_TARGET_PATH|DDD_REMOVE_DEFINITION|
                      DDD_EXACT_MATCH_ON_REMOVE, szDriveLetter,
                      pszNTDevice);

         if (!fResult)
            DEBUG_PRINT("DefineDosDevice failed", GetLastError());

         fResult = SetVolumeMountPoint (szDriveLetterAndSlash,
                        szUniqueVolumeName);

         if (!fResult)
            printf ("error %lu: could not add %s\n", GetLastError(),
                    szDriveLetterAndSlash);
      }
   }
}

/*-------------------------------------------------------------------
The PrintHelp function prints the command-line usage help.

Parameters
   pszAppName
      The name of the executable. Used in displaying the help.

-------------------------------------------------------------------*/
void PrintHelp (LPCSTR pszAppName)
{
   printf("Adds/removes a drive letter assignment for a device.\n\n");
   printf("Usage: %s <Drive> <Device name>   add a drive letter\n", pszAppName);
   printf("       %s -r <Drive>              remove a drive letter\n\n", pszAppName);
   printf("Example: %s e:\\ \\Device\\CdRom0\n", pszAppName);
   printf("         %s -r e:\\\n", pszAppName);
}

#if defined (DEBUG)
/*--------------------------------------------------------------------
The DebugPrint function prints a string to STDOUT.

Parameters
   pszMsg
      The string to be printed to STDOUT.
   dwErr
      The error code; usually obtained from GetLastError. If dwErr is
      zero, no error code is added to the error string. If dwErr is
      nonzero, the error code will be printed in the error string.
--------------------------------------------------------------------*/
void DebugPrint (LPCSTR pszMsg, DWORD dwErr)
{
   if (dwErr)
      printf("%s: %lu\n", pszMsg, dwErr);
   else
      printf("%s\n", pszMsg);
}
#endif

反斜杠居然显示不出来，论坛程序有BUG！ :mad:

还是自己到MSDN中搜索一下DefineDosDevice吧

老大,谢谢你的回复,但我的问题可能更为复杂,如何能把两个不同的物理目录进行虚拟合并,使他们看起来在同一个虚拟文件夹下呢?
但比Subst更为复杂的是,我的需求是把多个物理的文件或文件夹"拼"在一个虚拟文件夹下,所以DefineDosDevice是没办法做到的,是不是得自己写驱动啊?应该怎么实现,有没有类似的代码下载???


[编辑 -  6/10/04 by  redbirdli]