Dokan(Windows FUSE)学习笔记

1.      Dokan Library 简介

Dokan Library 帮助程序员在windows系统下轻松建立用户级文件系统，不需要写设备驱动，其与FUSE（Linux user mode file system）类似。

2.      Dokan原理

Dokan Library包含以下部分：
- user-mode library (dokan.dll)  LGPL
- driver (dokan.sys)             LGPL
- control program (dokanctl.exe) MIT
- mount service (mouter.exe)     MIT
- samples (mirror.c)             MIT

dokan.sys是内核态文件系统驱动，当此驱动安装之后，就可以创建自己的文件系统了。而我们创建文件系统（实现Dokan库的API）的程序称为文件系统程序。这时，程序提出的文件操作请求（例如CreateFile, ReadFile, WriteFile）就会送到Windows I/O subsystem (内核中运行)，后者会继续将请求送到dokan.sys。文件系统程序可以利用dokan.dll提供的函数将我们的回调函数（操作实现函数）注册到dokan.sys中，后者会在收到请求之后调用这些我们提供的函数。回调函数的结果会送回提出请求的程序。（可参见图一）

dokan.sys 相当于一个运行在内核态的代理，作为提出请求的程序和我们实现各种操作的文件系统程序的桥梁。至此，我们程序员就可以在用户态轻松的创建调试文件系统程序，大大提高了开发效率。

Dokan流程图

图一

3.      创建文件系统

与FUSE类似，我们的文件系统程序需要实现一个结构体中的各个操作DOKAN_OPERATIONS（声明在dokan.h中），然后该结构体作为参数调用DokanMain挂载文件系统。这些函数的参数与Windows APIs 一致，但必须做到线程安全，因为有可能有多个线程调用。

这些函数有个典型的调用顺序：
1. CreateFile(OpenDirectory, CreateFile)
2. Other functions
3. Cleanup
4. CloseFile

file creation functions (OpenDirectory, CreateFile,…)总是在file access operations (listing directory, reading file attributes, …)之前调用。当文件被CloseFile Windows API关闭时，Cleanup程序总是被dokan.sys调用。

返回值为0时表示操作成功。

每个函数的最后一个参数是DOKAN_FILE_INFO structure

<table border="0" cellpadding="0" cellspacing="0" style="margin-top: 0px !important; margin-right: 0px !important; margin-bottom: 0px !important; margin-left: 0px !important; padding-top: 0px !important; padding-right: 0px !important; padding-bottom: 0px !important; padding-left: 0px !important; border-bottom-width: 0px !important; border-bottom-style: solid; border-bottom-color: rgb(217, 217, 217); border-left-width: 0px !important; border-left-style: solid; border-left-color: rgb(217, 217, 217); border-top-left-radius: 0px 0px !important; border-top-right-radius: 0px 0px !important; border-bottom-right-radius: 0px 0px !important; border-bottom-left-radius: 0px 0px !important; background-image: none !important; background-attachment: initial !important; background-origin: initial !important; background-clip: initial !important; background-color: initial !important; border-top-width: 0px !important; border-right-width: 0px !important; border-style: initial !important; border-color: initial !important; 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padding-left: 0px !important; text-align: left !important; border-top-width: 0px !important; border-top-style: solid; border-top-color: rgb(217, 217, 217); border-right-width: 0px !important; border-right-style: solid; border-right-color: rgb(217, 217, 217); border-top-left-radius: 0px 0px !important; border-top-right-radius: 0px 0px !important; border-bottom-right-radius: 0px 0px !important; border-bottom-left-radius: 0px 0px !important; background-image: none !important; background-attachment: initial !important; background-origin: initial !important; background-clip: initial !important; background-color: initial !important; border-bottom-width: 0px !important; border-left-width: 0px !important; border-style: initial !important; border-color: initial !important; bottom: auto !important; float: none !important; height: auto !important; left: auto !important; line-height: 1.1em !important; outline-width: 0px !important; outline-style: initial !important; outline-color: initial !important; overflow-x: visible !important; overflow-y: visible !important; position: static !important; right: auto !important; top: auto !important; vertical-align: baseline !important; width: auto !important; box-sizing: content-box !important; font-family: Consolas, 'Bitstream Vera Sans Mono', 'Courier New', Courier, monospace !important; font-weight: normal !important; font-style: normal !important; font-size: 1em !important; min-height: inherit !important; color: rgb(175, 175, 175) !important; background-position: initial initial !important; background-repeat: initial initial !important; ">123456<td style="margin-top: 0px !important; margin-right: 0px !important; margin-bottom: 0px !important; margin-left: 0px !important; padding-top: 0px !important; padding-right: 0px !important; padding-bottom: 0px !important; padding-left: 0px !important; text-align: left !important; border-top-width: 0px !important; border-top-style: solid; border-top-color: rgb(217, 217, 217); border-right-width: 0px !important; border-right-style: solid; border-right-color: rgb(217, 217, 217); border-top-left-radius: 0px 0px !important; border-top-right-radius: 0px 0px !important; border-bottom-right-radius: 0px 0px !important; border-bottom-left-radius: 0px 0px !important; background-image: none !important; background-attachment: initial !important; background-origin: initial !important; background-clip: initial !important; background-color: initial !important; border-bottom-width: 0px !important; border-left-width: 0px !important; border-style: initial !important; border-color: initial !important; bottom: auto !important; float: none !important; height: auto !important; left: auto !important; line-height: 1.1em !important; outline-width: 0px !important; outline-style: initial !important; outline-color: initial !important; overflow-x: visible !important; overflow-y: visible !important; position: static !important; right: auto !important; top: auto !important; vertical-align: baseline !important; width: 855px; box-sizing: content-box !important; font-family: Consolas, 'Bitstream Vera Sans Mono', 'Courier New', Courier, monospace !important; font-weight: normal !important; font-style: normal !important; font-size: 1em !important; min-height: inherit !important; background-position: initial initial !important; background-repeat: initial initial !important; ">typedefstruct_DOKAN_FILE_INFO {ULONG64Context;     //文件系统程序维护，可作为文件句柄ULONG64DokanContext;  //Dokan Library维护ULONG   ProcessId;   //操作IDBOOL    IsDirectory;  //目录= TRUE} DOKAN_FILE_INFO, *PDOKAN_FILE_INFO;

每一个文件句柄都与一个DOKAN_FILE_INFO struct对应。该结构创建在文件被CreateFile系统调用打开时，回收在文件被CloseFile系统调用关闭时。

下面是几个操作的声明：

<table border="0" cellpadding="0" cellspacing="0" style="margin-top: 0px !important; margin-right: 0px !important; margin-bottom: 0px !important; margin-left: 0px !important; padding-top: 0px !important; padding-right: 0px !important; padding-bottom: 0px !important; padding-left: 0px !important; border-bottom-width: 0px !important; border-bottom-style: solid; border-bottom-color: rgb(217, 217, 217); border-left-width: 0px !important; border-left-style: solid; border-left-color: rgb(217, 217, 217); border-top-left-radius: 0px 0px !important; border-top-right-radius: 0px 0px !important; border-bottom-right-radius: 0px 0px !important; border-bottom-left-radius: 0px 0px !important; background-image: none !important; background-attachment: initial !important; background-origin: initial !important; background-clip: initial !important; background-color: initial !important; border-top-width: 0px !important; border-right-width: 0px !important; border-style: initial !important; border-color: initial !important; 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padding-left: 0px !important; text-align: left !important; border-top-width: 0px !important; border-top-style: solid; border-top-color: rgb(217, 217, 217); border-right-width: 0px !important; border-right-style: solid; border-right-color: rgb(217, 217, 217); border-top-left-radius: 0px 0px !important; border-top-right-radius: 0px 0px !important; border-bottom-right-radius: 0px 0px !important; border-bottom-left-radius: 0px 0px !important; background-image: none !important; background-attachment: initial !important; background-origin: initial !important; background-clip: initial !important; background-color: initial !important; border-bottom-width: 0px !important; border-left-width: 0px !important; border-style: initial !important; border-color: initial !important; bottom: auto !important; float: none !important; height: auto !important; left: auto !important; line-height: 1.1em !important; outline-width: 0px !important; outline-style: initial !important; outline-color: initial !important; overflow-x: visible !important; overflow-y: visible !important; position: static !important; right: auto !important; top: auto !important; vertical-align: baseline !important; width: auto !important; box-sizing: content-box !important; font-family: Consolas, 'Bitstream Vera Sans Mono', 'Courier New', Courier, monospace !important; font-weight: normal !important; font-style: normal !important; font-size: 1em !important; min-height: inherit !important; color: rgb(175, 175, 175) !important; background-position: initial initial !important; background-repeat: initial initial !important; ">12345678910111213141516171819202122232425<td style="margin-top: 0px !important; margin-right: 0px !important; margin-bottom: 0px !important; margin-left: 0px !important; padding-top: 0px !important; padding-right: 0px !important; padding-bottom: 0px !important; padding-left: 0px !important; text-align: left !important; border-top-width: 0px !important; border-top-style: solid; border-top-color: rgb(217, 217, 217); border-right-width: 0px !important; border-right-style: solid; border-right-color: rgb(217, 217, 217); border-top-left-radius: 0px 0px !important; border-top-right-radius: 0px 0px !important; border-bottom-right-radius: 0px 0px !important; border-bottom-left-radius: 0px 0px !important; background-image: none !important; background-attachment: initial !important; background-origin: initial !important; background-clip: initial !important; background-color: initial !important; border-bottom-width: 0px !important; border-left-width: 0px !important; border-style: initial !important; border-color: initial !important; bottom: auto !important; float: none !important; height: auto !important; left: auto !important; line-height: 1.1em !important; outline-width: 0px !important; outline-style: initial !important; outline-color: initial !important; overflow-x: visible !important; overflow-y: visible !important; position: static !important; right: auto !important; top: auto !important; vertical-align: baseline !important; width: 846px; box-sizing: content-box !important; font-family: Consolas, 'Bitstream Vera Sans Mono', 'Courier New', Courier, monospace !important; font-weight: normal !important; font-style: normal !important; font-size: 1em !important; min-height: inherit !important; background-position: initial initial !important; background-repeat: initial initial !important; ">int(*CreateFile) ( LPCWSTR,      // FileName DWORD,        // DesiredAccess DWORD,        // ShareMode DWORD,        // CreationDisposition DWORD,        // FlagsAndAttributes PDOKAN_FILE_INFO); int(*OpenDirectory) ( LPCWSTR,          // FileName PDOKAN_FILE_INFO); int(*CreateDirectory) ( LPCWSTR,          // FileName PDOKAN_FILE_INFO); //注意设置IsDirectory = TRUE<table border="0" cellpadding="0" cellspacing="0" style="margin-top: 0px !important; margin-right: 0px !important; margin-bottom: 0px !important; margin-left: 0px !important; padding-top: 0px !important; padding-right: 0px !important; padding-bottom: 0px !important; padding-left: 0px !important; border-bottom-width: 0px !important; border-bottom-style: solid; border-bottom-color: rgb(217, 217, 217); border-left-width: 0px !important; border-left-style: solid; border-left-color: rgb(217, 217, 217); border-top-left-radius: 0px 0px !important; border-top-right-radius: 0px 0px !important; border-bottom-right-radius: 0px 0px !important; border-bottom-left-radius: 0px 0px !important; background-image: none !important; background-attachment: initial !important; background-origin: initial !important; background-clip: initial !important; background-color: initial !important; border-top-width: 0px !important; border-right-width: 0px !important; border-style: initial !important; border-color: initial !important; bottom: auto !important; float: none !important; height: auto !important; left: auto !important; line-height: 1.1em !important; outline-width: 0px !important; outline-style: initial !important; outline-color: initial !important; overflow-x: visible !important; overflow-y: visible !important; position: static !important; right: auto !important; text-align: left !important; top: auto !important; vertical-align: baseline !important; width: 998px; box-sizing: content-box !important; font-family: Consolas, 'Bitstream Vera Sans Mono', 'Courier New', Courier, monospace !important; font-weight: normal !important; font-style: normal !important; font-size: 1em !important; min-height: inherit !important; background-position: initial initial !important; background-repeat: initial initial !important; "><td style="margin-top: 0px !important; margin-right: 0px !important; margin-bottom: 0px !important; margin-left: 0px !important; padding-top: 0px !important; padding-right: 0px !important; padding-bottom: 0px !important; padding-left: 0px !important; text-align: left !important; border-top-width: 0px !important; border-top-style: solid; border-top-color: rgb(217, 217, 217); border-right-width: 0px !important; border-right-style: solid; border-right-color: rgb(217, 217, 217); border-top-left-radius: 0px 0px !important; border-top-right-radius: 0px 0px !important; border-bottom-right-radius: 0px 0px !important; border-bottom-left-radius: 0px 0px !important; background-image: none !important; background-attachment: initial !important; background-origin: initial !important; background-clip: initial !important; background-color: initial !important; border-bottom-width: 0px !important; border-left-width: 0px !important; border-style: initial !important; border-color: initial !important; bottom: auto !important; float: none !important; height: auto !important; left: auto !important; line-height: 1.1em !important; outline-width: 0px !important; outline-style: initial !important; outline-color: initial !important; overflow-x: visible !important; overflow-y: visible !important; position: static !important; right: auto !important; top: auto !important; vertical-align: baseline !important; width: auto !important; box-sizing: content-box !important; font-family: Consolas, 'Bitstream Vera Sans Mono', 'Courier New', Courier, monospace !important; font-weight: normal !important; font-style: normal !important; font-size: 1em !important; min-height: inherit !important; color: rgb(175, 175, 175) !important; background-position: initial initial !important; background-repeat: initial initial !important; ">12345678910111213141516171819202122232425262728293031323334<td style="margin-top: 0px !important; margin-right: 0px !important; margin-bottom: 0px !important; margin-left: 0px !important; padding-top: 0px !important; padding-right: 0px !important; padding-bottom: 0px !important; padding-left: 0px !important; text-align: left !important; border-top-width: 0px !important; border-top-style: solid; border-top-color: rgb(217, 217, 217); border-right-width: 0px !important; border-right-style: solid; border-right-color: rgb(217, 217, 217); border-top-left-radius: 0px 0px !important; border-top-right-radius: 0px 0px !important; border-bottom-right-radius: 0px 0px !important; border-bottom-left-radius: 0px 0px !important; background-image: none !important; background-attachment: initial !important; background-origin: initial !important; background-clip: initial !important; background-color: initial !important; border-bottom-width: 0px !important; border-left-width: 0px !important; border-style: initial !important; border-color: initial !important; bottom: auto !important; float: none !important; height: auto !important; left: auto !important; line-height: 1.1em !important; outline-width: 0px !important; outline-style: initial !important; outline-color: initial !important; overflow-x: visible !important; overflow-y: visible !important; position: static !important; right: auto !important; top: auto !important; vertical-align: baseline !important; width: 953px; box-sizing: content-box !important; font-family: Consolas, 'Bitstream Vera Sans Mono', 'Courier New', Courier, monospace !important; font-weight: normal !important; font-style: normal !important; font-size: 1em !important; min-height: inherit !important; background-position: initial initial !important; background-repeat: initial initial !important; ">//CloseHandle ( Windows API)执行之后调用，如果文件句柄在//CreateFile中创建，应该在此释放，而不是在CloseFile。//如果用户在内存中缓存了文件，调用Cleanup之后还有可能调用读写//操作。int(*Cleanup) ( LPCWSTR,      // FileName PDOKAN_FILE_INFO); //如果用户调用CloseHandle后再打开相同文件，CreateFile之前可能//不会再调用CloseFile，这可能会出共享错误。int(*CloseFile) ( LPCWSTR,      // FileName PDOKAN_FILE_INFO); int(*FindFiles) ( LPCWSTR,           // PathName PFillFindData,     // call this function with PWIN32_FIND_DATAW PDOKAN_FILE_INFO); //  (see PFillFindData definition) // You should implement either FindFires or FindFilesWithPattern int(*FindFilesWithPattern) ( LPCWSTR,           // PathName LPCWSTR,           // SearchPattern PFillFindData,     // call this function with PWIN32_FIND_DATAW PDOKAN_FILE_INFO);

上面两个函数是回应列目录项操作请求的。对每一个目录项，文件系统程序都会调用函数FillFindData( &win32FindDataw,  DokanFileInfo )。由于Windows的shell对于模式匹配不支持，文件系统程序就要执行通配模式。当文件系统程序实现FindFiles，DokanLibrary会自动添加通配模式，我们也可以自己实现FindFilesWithPattern来加以控制。DokanIsNameInExpression (dokan.dll)函数就是用来实现模式匹配的。

4.      挂载

前面已经提到，可以调用DokanMain函数来挂载文件系统。该程序会阻塞到文件系统被卸载。

我们的文件系统要做两件事，一是为Dokan运行库填写DokanOptions，二是填写带各个操作函数指针的DokanOperations作为DokanMain的参数。

<table border="0" cellpadding="0" cellspacing="0" style="margin-top: 0px !important; margin-right: 0px !important; margin-bottom: 0px !important; margin-left: 0px !important; padding-top: 0px !important; padding-right: 0px !important; padding-bottom: 0px !important; padding-left: 0px !important; border-bottom-width: 0px !important; border-bottom-style: solid; border-bottom-color: rgb(217, 217, 217); border-left-width: 0px !important; border-left-style: solid; border-left-color: rgb(217, 217, 217); border-top-left-radius: 0px 0px !important; border-top-right-radius: 0px 0px !important; border-bottom-right-radius: 0px 0px !important; border-bottom-left-radius: 0px 0px !important; background-image: none !important; background-attachment: initial !important; background-origin: initial !important; background-clip: initial !important; background-color: initial !important; border-top-width: 0px !important; border-right-width: 0px !important; border-style: initial !important; border-color: initial !important; bottom: auto !important; float: none !important; height: auto !important; left: auto !important; line-height: 1.1em !important; outline-width: 0px !important; outline-style: initial !important; outline-color: initial !important; overflow-x: visible !important; overflow-y: visible !important; position: static !important; right: auto !important; text-align: left !important; top: auto !important; vertical-align: baseline !important; width: 891px; box-sizing: content-box !important; font-family: Consolas, 'Bitstream Vera Sans Mono', 'Courier New', Courier, monospace !important; font-weight: normal !important; font-style: normal !important; font-size: 1em !important; min-height: inherit !important; background-position: initial initial !important; background-repeat: initial initial !important; "><td style="margin-top: 0px !important; margin-right: 0px !important; margin-bottom: 0px !important; margin-left: 0px !important; padding-top: 0px !important; padding-right: 0px !important; padding-bottom: 0px !important; padding-left: 0px !important; text-align: left !important; border-top-width: 0px !important; border-top-style: solid; border-top-color: rgb(217, 217, 217); border-right-width: 0px !important; border-right-style: solid; border-right-color: rgb(217, 217, 217); border-top-left-radius: 0px 0px !important; border-top-right-radius: 0px 0px !important; border-bottom-right-radius: 0px 0px !important; border-bottom-left-radius: 0px 0px !important; background-image: none !important; background-attachment: initial !important; background-origin: initial !important; background-clip: initial !important; background-color: initial !important; border-bottom-width: 0px !important; border-left-width: 0px !important; border-style: initial !important; border-color: initial !important; bottom: auto !important; float: none !important; height: auto !important; left: auto !important; line-height: 1.1em !important; outline-width: 0px !important; outline-style: initial !important; outline-color: initial !important; overflow-x: visible !important; overflow-y: visible !important; position: static !important; right: auto !important; top: auto !important; vertical-align: baseline !important; width: auto !important; box-sizing: content-box !important; font-family: Consolas, 'Bitstream Vera Sans Mono', 'Courier New', Courier, monospace !important; font-weight: normal !important; font-style: normal !important; font-size: 1em !important; min-height: inherit !important; color: rgb(175, 175, 175) !important; background-position: initial initial !important; background-repeat: initial initial !important; ">123456789101112131415161718192021<td style="margin-top: 0px !important; margin-right: 0px !important; margin-bottom: 0px !important; margin-left: 0px !important; padding-top: 0px !important; padding-right: 0px !important; padding-bottom: 0px !important; padding-left: 0px !important; text-align: left !important; border-top-width: 0px !important; border-top-style: solid; border-top-color: rgb(217, 217, 217); border-right-width: 0px !important; border-right-style: solid; border-right-color: rgb(217, 217, 217); border-top-left-radius: 0px 0px !important; border-top-right-radius: 0px 0px !important; border-bottom-right-radius: 0px 0px !important; border-bottom-left-radius: 0px 0px !important; background-image: none !important; background-attachment: initial !important; background-origin: initial !important; background-clip: initial !important; background-color: initial !important; border-bottom-width: 0px !important; border-left-width: 0px !important; border-style: initial !important; border-color: initial !important; bottom: auto !important; float: none !important; height: auto !important; left: auto !important; line-height: 1.1em !important; outline-width: 0px !important; outline-style: initial !important; outline-color: initial !important; overflow-x: visible !important; overflow-y: visible !important; position: static !important; right: auto !important; top: auto !important; vertical-align: baseline !important; width: 846px; box-sizing: content-box !important; font-family: Consolas, 'Bitstream Vera Sans Mono', 'Courier New', Courier, monospace !important; font-weight: normal !important; font-style: normal !important; font-size: 1em !important; min-height: inherit !important; background-position: initial initial !important; background-repeat: initial initial !important; ">intDOKANAPI DokanMain( PDOKAN_OPTIONS    DokanOptions, PDOKAN_OPERATIONS DokanOperations); typedefstruct_DOKAN_OPTIONS { USHORT  Version;  // Supported Dokan Version, ex. "530" (Dokan ver 0.5.3) ULONG   ThreadCount;  // number of threads to be used ULONG   Options;      // combination of DOKAN_OPTIONS_* ULONG64GlobalContext;  // FileSystem can use this variable LPCWSTRMountPoint;     // mount point "M:\" (drive letter) or // "C:\mount\dokan" (path in NTFS) } DOKAN_OPTIONS, *PDOKAN_OPTIONS;5.      卸载

调用 DokanUnmount进行文件系统的卸载。用户也可以使用 DokanCtl 像这样进行卸载:

> dokanctl.exe /u DriveLetter