Sometimes you would like to know if the tray of your CD/DVD/Bluray drive is open, closed and if a media is inserted. The following example shows how to archive that with C++. The return codes of the function GetDriveStatus() are:
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1 2 3 4 |
-1 DRIVE_NOT_READY 0 DRIVE_CLOSED_NO_MEDIA 1 DRIVE_OPEN 2 DRIVE_CLOSED_MEDIA_PRESENT |
And now the example:
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//** Defines taken from ntddscsi.h in MS Windows DDK CD #define SCSI_IOCTL_DATA_OUT 0 //Give data to SCSI device (e.g. for writing) #define SCSI_IOCTL_DATA_IN 1 //Get data from SCSI device (e.g. for reading) #define SCSI_IOCTL_DATA_UNSPECIFIED 2 //No data (e.g. for ejecting) #define MAX_SENSE_LEN 18 //Sense data max length #define IOCTL_SCSI_PASS_THROUGH_DIRECT 0x4D014 typedef struct _SCSI_PASS_THROUGH_DIRECT { USHORT Length; UCHAR ScsiStatus; UCHAR PathId; UCHAR TargetId; UCHAR Lun; UCHAR CdbLength; UCHAR SenseInfoLength; UCHAR DataIn; ULONG DataTransferLength; ULONG TimeOutValue; PVOID DataBuffer; ULONG SenseInfoOffset; UCHAR Cdb[16]; }SCSI_PASS_THROUGH_DIRECT, *PSCSI_PASS_THROUGH_DIRECT; typedef struct _SCSI_PASS_THROUGH_DIRECT_AND_SENSE_BUFFER { SCSI_PASS_THROUGH_DIRECT sptd; UCHAR SenseBuf[MAX_SENSE_LEN]; }T_SPDT_SBUF; int GetDriveStatus(const CStdString &strPath, bool bStatusEx) { HANDLE hDevice; // handle to the drive to be examined int iResult; // results flag ULONG ulChanges=0; DWORD dwBytesReturned; T_SPDT_SBUF sptd_sb; //SCSI Pass Through Direct variable. byte DataBuf[8]; //Buffer for holding data to/from drive. CLog::Log(LOGDEBUG, __FUNCTION__": Requesting status for drive %s.", strPath.c_str()); hDevice = CreateFile( strPath.c_str(), // drive 0, // no access to the drive FILE_SHARE_READ, // share mode NULL, // default security attributes OPEN_EXISTING, // disposition FILE_ATTRIBUTE_READONLY, // file attributes NULL); if (hDevice == INVALID_HANDLE_VALUE) // cannot open the drive { CLog::Log(LOGERROR, __FUNCTION__": Failed to CreateFile for %s.", strPath.c_str()); return -1; } CLog::Log(LOGDEBUG, __FUNCTION__": Requesting media status for drive %s.", strPath.c_str()); iResult = DeviceIoControl((HANDLE) hDevice, // handle to device IOCTL_STORAGE_CHECK_VERIFY2, // dwIoControlCode NULL, // lpInBuffer 0, // nInBufferSize &ulChanges, // lpOutBuffer sizeof(ULONG), // nOutBufferSize &dwBytesReturned , // number of bytes returned NULL ); // OVERLAPPED structure CloseHandle(hDevice); if(iResult == 1) return 2; // don't request the tray status as we often doesn't need it if(!bStatusEx) return 0; hDevice = CreateFile( strPath.c_str(), GENERIC_READ | GENERIC_WRITE, FILE_SHARE_READ | FILE_SHARE_WRITE, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_READONLY, NULL); if (hDevice == INVALID_HANDLE_VALUE) { CLog::Log(LOGERROR, __FUNCTION__": Failed to CreateFile2 for %s.", strPath.c_str()); return -1; } sptd_sb.sptd.Length=sizeof(SCSI_PASS_THROUGH_DIRECT); sptd_sb.sptd.PathId=0; sptd_sb.sptd.TargetId=0; sptd_sb.sptd.Lun=0; sptd_sb.sptd.CdbLength=10; sptd_sb.sptd.SenseInfoLength=MAX_SENSE_LEN; sptd_sb.sptd.DataIn=SCSI_IOCTL_DATA_IN; sptd_sb.sptd.DataTransferLength=sizeof(DataBuf); sptd_sb.sptd.TimeOutValue=2; sptd_sb.sptd.DataBuffer=(PVOID)&(DataBuf); sptd_sb.sptd.SenseInfoOffset=sizeof(SCSI_PASS_THROUGH_DIRECT); sptd_sb.sptd.Cdb[0]=0x4a; sptd_sb.sptd.Cdb[1]=1; sptd_sb.sptd.Cdb[2]=0; sptd_sb.sptd.Cdb[3]=0; sptd_sb.sptd.Cdb[4]=0x10; sptd_sb.sptd.Cdb[5]=0; sptd_sb.sptd.Cdb[6]=0; sptd_sb.sptd.Cdb[7]=0; sptd_sb.sptd.Cdb[8]=8; sptd_sb.sptd.Cdb[9]=0; sptd_sb.sptd.Cdb[10]=0; sptd_sb.sptd.Cdb[11]=0; sptd_sb.sptd.Cdb[12]=0; sptd_sb.sptd.Cdb[13]=0; sptd_sb.sptd.Cdb[14]=0; sptd_sb.sptd.Cdb[15]=0; ZeroMemory(DataBuf, 8); ZeroMemory(sptd_sb.SenseBuf, MAX_SENSE_LEN); //Send the command to drive CLog::Log(LOGDEBUG, __FUNCTION__": Requesting tray status for drive %s.", strPath.c_str()); iResult = DeviceIoControl((HANDLE) hDevice, IOCTL_SCSI_PASS_THROUGH_DIRECT, (PVOID)&sptd_sb, (DWORD)sizeof(sptd_sb), (PVOID)&sptd_sb, (DWORD)sizeof(sptd_sb), &dwBytesReturned, NULL); CloseHandle(hDevice); if(iResult) { if(DataBuf[5] == 0) // tray close return 0; else if(DataBuf[5] == 1) // tray open return 1; else return 2; // tray closed, media present } CLog::Log(LOGERROR, __FUNCTION__": Could not determine tray status %d", GetLastError()); return -1; } |
We first check in line 57 with IOCTL_STORAGE_CHECK_VERIFY2 if we have a media in our drive. If this returns 1 we have a medium loaded and we can early return and save another call to DeviceIoControl().
In line 123 we finally request the tray status with a IOCTL_SCSI_PASS_THROUGH_DIRECT call.