一般，我們獲取SD ID是通過2種方法（實際上市一回事，只不過是形式上不同而已），一是CreateFile(L"DSK2:", ...); 再DeviceIoControl(hFile, IOCTL_DISK_GET_STORAGEID, NULL, 0, &storeID, MAX_PAT,&dwBytesRead, NULL); 這是一種比較常用的方法，很好用，得到的結果也很正確；第二種方法就是CreateFile(L"//StorageCard//VOL:", ...); 再DeviceIoControl(hFile, IOCTL_DISK_GET_STORAGEID, NULL, 0, &storeID, MAX_PAT,&dwBytesRead, NULL); 這也是我今天要說的方法，在wince5.0 中這個運行的很好，沒有錯誤，但到了wince6.0中這個方法就不行了，CreateFile 可以得到句柄，但是DeviceIoControl 就不行了, Why? 是DeviceIoControl 有問題還是CreateFile 有問題？所以我們就不得去找微軟的代碼了，可微軟文件系統的代碼也沒有全部給出來，DeviceIoControl 沒有找到實際的執行流程，如果誰知道的話，麻煩告訴我一聲！找CreateFile, 根據vcleaner 的提示，找到D:/WINCE600/PRIVATE/WINCEOS/COREOS/STORAGE/FSDMGR 目錄下的volumeapi.cpp文件，找到 FSDMGR_CreateFileW 函數，我加了打印語句，CreateFile(L"//StorageCard//VOL:", ...); 的確是調用了這個函數，而CreateFile(L"DSK2:", ...); 沒有調用這個函數，所以說應該是CreateFile出了問題！仔細分析這個函數，感覺創建句柄的時候的確有點問題，它創建的是一個文件類型句柄，不是一個Device 類型句柄，所以調用DeviceIoControl 會失敗，以下是我修改後的代碼：
EXTERN_C HANDLE FSDMGR_CreateFileW (MountedVolume_t* pVolume, HANDLE hProcess,
const WCHAR* pPathName, DWORD Access, DWORD ShareMode,
SECURITY_ATTRIBUTES* pSecurityAttributes, DWORD Create,
DWORD FlagsAndAttributes, HANDLE hTemplate,
PSECURITY_DESCRIPTOR pSecurityDescriptor, DWORD SecurityDescriptorSize)
{
HANDLE h = INVALID_HANDLE_VALUE;
SECURITY_ATTRIBUTES SecurityAttributes;
DEBUGCHK (!pSecurityAttributes);
if (pSecurityDescriptor) {
SecurityAttributes.nLength = sizeof (SECURITY_ATTRIBUTES);
SecurityAttributes.lpSecurityDescriptor = pSecurityDescriptor;
SecurityAttributes.bInheritHandle = FALSE;
pSecurityAttributes = &SecurityAttributes;
}
LRESULT lResult = pVolume->EnterWithWait ();
if (ERROR_SUCCESS == lResult) {
// Get the topmost file system object associated with the volume.
// If another filter is hooked between now and the time we call
// create file, we'll still use this one. This file system object
// will be referenced by the handle object.
FileSystem_t* pFileSystem = pVolume->GetFileSystem ();
DWORD Attributes = 0;
if (OPEN_EXISTING != Create) {
// If not trying to open an existing file, there is the
// possibility that we will create a new one. In order to
// properly generate notifications we need to detect whether or
// not the file already exists using GetFileAttributes.
Attributes = pFileSystem->GetFileAttributesW (pPathName);
}
HANDLE hInt = pFileSystem->CreateFileW (hProcess, pPathName, Access,
ShareMode, pSecurityAttributes, Create,
FlagsAndAttributes, hTemplate);
if (INVALID_HANDLE_VALUE != hInt) {
// The file system succeeded creating/opening the file, so
// allocate an FileSystemHandle_t object and associate it with the
// MountedVolume_t object.
// Indicate whether or not this is a console or psuedo-device
// handle when creating the FileSystemHandle_t object. This will dictate
// how notifications are performed on the handle.
DWORD HandleType = FileSystemHandle_t::HDL_FILE; //Hugo
//DWORD HandleType = FileSystemHandle_t::HDL_FILE | FileSystemHandle_t::HDL_PSUEDO;
if (IsPsuedoDeviceName(pPathName))
{
HandleType |= FileSystemHandle_t::HDL_PSUEDO;
}
if (IsConsoleName (pPathName)) {
HandleType |= FileSystemHandle_t::HDL_CONSOLE;
}
//RETAILMSG(1, (L"Hugo CreateFile:AllocFileHandle /r/n "));
// Allocte a new handle object to track this item.
h = pVolume->AllocFileHandle (reinterpret_cast<DWORD> (hInt),
HandleType, pFileSystem, pPathName, Access);
if (INVALID_HANDLE_VALUE != h) {
// Perform notifications only when the handle is for a real file,
// not a pseudo device handle or console handle. Devices and streams
// shouldn't ever generate notifications.
//if (FileSystemHandle_t::HDL_FILE == HandleType && hugo
//!IsPsuedoDeviceName (pPathName)) {
if (FileSystemHandle_t::HDL_FILE == HandleType ) {
// Successfully opened the file. Perform file notifications
// as required.
if (INVALID_FILE_ATTRIBUTES == Attributes) {
// The file did not previously exist; notify that it has
// been added.
pVolume->NotifyPathChange (pPathName, FALSE, FILE_ACTION_ADDED);
} else if ((CREATE_ALWAYS == Create) ||
(TRUNCATE_EXISTING == Create)) {
// The file previously existed but is being re-created or
// truncated so notify that it has changed.
pVolume->NotifyPathChange (pPathName, FALSE, FILE_ACTION_MODIFIED);
}
}
} else {
// Failed to allocate a handle object, so close the handle
// that was returned by the file system.
pFileSystem->CloseFile (reinterpret_cast<DWORD> (hInt));
}
} else if (pPathName && (wcsicmp (pPathName, L"//VOL:") == 0)) {
// TODO: Privilege check for raw disk i/o. This requires more privilege than file i/o.
// Clear error code set by the FSD when it failed to open VOL: on its own.
SetLastError (ERROR_SUCCESS);
// We failed to open the file, but if it is VOL: special case this
// and allow direct partition access.
h = pVolume->AllocFileHandle (reinterpret_cast<DWORD> (hInt),
FileSystemHandle_t::HDL_PSUEDO, pFileSystem, pPathName, Access);
}
pVolume->Exit ();
} else {
SetLastError (lResult);
}
return h;
}
上面紅色的是我添加的（注意我屏蔽的那行代碼，開始我沒加下面if 語句，就加了屏蔽的那行代碼，系統跑不起來，有誰能告訴我why?）,這樣就OK,一切正常，sd id 也可以正確的讀出來了!不知道vcleaner 跟微軟確認的怎麼樣了，這是不是wince6 的bug?