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// this file almost totally copied from MSDN
#include <windows.h>
#include <stdio.h>
#include <winioctl.h>
#define LOCK_TIMEOUT 3000 // 10 Seconds
#define LOCK_RETRIES 20
static HANDLE OpenVolume(TCHAR cDriveLetter)
{
HANDLE hVolume;
UINT uDriveType;
wchar_t szVolumeName[8] = {0};
wchar_t szRootName[5] = {0};
DWORD dwAccessFlags = 0;
wsprintf(szRootName, L"%c:\\", cDriveLetter);
uDriveType = GetDriveType(szRootName);
switch(uDriveType) {
case DRIVE_REMOVABLE:
dwAccessFlags = GENERIC_READ | GENERIC_WRITE;
break;
case DRIVE_CDROM:
dwAccessFlags = GENERIC_READ;
break;
default:
printf("Cannot eject. Drive type is incorrect.\n");
return INVALID_HANDLE_VALUE;
}
wsprintf(szVolumeName, L"\\\\.\\%c:", cDriveLetter);
hVolume = CreateFile( szVolumeName,
dwAccessFlags,
FILE_SHARE_READ | FILE_SHARE_WRITE,
NULL,
OPEN_EXISTING,
0,
NULL );
if (hVolume == INVALID_HANDLE_VALUE)
printf("CreateFile error %d\n", GetLastError());
return hVolume;
}
static BOOL CloseVolume(HANDLE hVolume)
{
return CloseHandle(hVolume);
}
static BOOL LockVolume(HANDLE hVolume)
{
DWORD dwBytesReturned;
DWORD dwSleepAmount;
int nTryCount;
dwSleepAmount = LOCK_TIMEOUT / LOCK_RETRIES;
// Do this in a loop until a timeout period has expired
for (nTryCount = 0; nTryCount < LOCK_RETRIES; nTryCount++) {
if (DeviceIoControl(hVolume,
FSCTL_LOCK_VOLUME,
NULL, 0,
NULL, 0,
&dwBytesReturned,
NULL))
return TRUE;
Sleep(dwSleepAmount);
}
return FALSE;
}
static BOOL DismountVolume(HANDLE hVolume)
{
DWORD dwBytesReturned;
return DeviceIoControl( hVolume,
FSCTL_DISMOUNT_VOLUME,
NULL, 0,
NULL, 0,
&dwBytesReturned,
NULL);
}
static BOOL PreventRemovalOfVolume(HANDLE hVolume, BOOL fPreventRemoval)
{
DWORD dwBytesReturned;
PREVENT_MEDIA_REMOVAL PMRBuffer;
PMRBuffer.PreventMediaRemoval = fPreventRemoval;
return DeviceIoControl( hVolume,
IOCTL_STORAGE_MEDIA_REMOVAL,
&PMRBuffer, sizeof(PREVENT_MEDIA_REMOVAL),
NULL, 0,
&dwBytesReturned,
NULL);
}
static int AutoEjectVolume(HANDLE hVolume)
{
DWORD dwBytesReturned;
return DeviceIoControl( hVolume,
IOCTL_STORAGE_EJECT_MEDIA,
NULL, 0,
NULL, 0,
&dwBytesReturned,
NULL);
}
BOOL EjectVolume(TCHAR cDriveLetter)
{
HANDLE hVolume;
BOOL fAutoEject = FALSE;
hVolume = OpenVolume(cDriveLetter);
if (hVolume == INVALID_HANDLE_VALUE)
return FALSE;
// Lock and dismount the volume.
if (LockVolume(hVolume) && DismountVolume(hVolume)) {
// Set prevent removal to false and eject the volume.
if (PreventRemovalOfVolume(hVolume, FALSE) && AutoEjectVolume(hVolume))
fAutoEject = TRUE;
}
// Close the volume so other processes can use the drive.
if (!CloseVolume(hVolume))
return FALSE;
if (fAutoEject) return TRUE;
else return FALSE;
}
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