Question

I’m trying to call SetupDiGetDriverInfoDetail from a C# application. The call fails and the win32 error I get back is 0x6F8 (“The supplied user buffer is not valid for the requested operation.”). Up to this point I have been able to call other setupdi functions with success so I think the problem is with the way that I marshal either the function or SP_DRVINFO_DETAIL_DATA struct.

I’m not sure, but I think the problem may be with the HardwareID member of the SP_DRVINFO_DETAIL_DATA struct. I’ve tried specifying the HardwareID as different types (ex. a byte array and allocating the buffer before setting the size and calling the function), but always the same error. If anyone has any experience with this call or has any pointers, I would appreciate the help.

Below is my structure definition, function import and code snippet. In this version I use a fixed size HardwareID buffer. I’ve also tried specifying a buffer size of 1 expecting an “buffer too small” error, but I always get the “invalid buffer” error.

    [DllImport("setupapi.dll", SetLastError = true)]
    internal static extern Int32 SetupDiGetDriverInfoDetail(
        IntPtr DeviceInfoSet,
        SP_DEVINFO_DATA DeviceInfoData,
        SP_DRVINFO_DATA DriverInfoData,
        ref SP_DRVINFO_DETAIL_DATA DriverInfoDetailData,
        Int32 DriverInfoDetailDataSize,
        ref Int32 RequiredSize);


    [StructLayout(LayoutKind.Sequential, Pack = 1)]
    internal struct SP_DRVINFO_DETAIL_DATA
    {
        public Int32 cbSize;
        public System.Runtime.InteropServices.ComTypes.FILETIME InfDate;
        public Int32 CompatIDsOffset;
        public Int32 CompatIDsLength;
        public IntPtr Reserved;
        [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 256)]
        public String SectionName;
        [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 256)]
        public String InfFileName;
        [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 256)]
        public String DrvDescription;
        [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 256)]
        public String HardwareID;
    };

SetupApiWrapper.SP_DRVINFO_DETAIL_DATA DriverInfoDetailData = new SetupApiWrapper.SP_DRVINFO_DETAIL_DATA();
DriverInfoDetailData.cbSize = Marshal.SizeOf(DriverInfoDetailData);

result = SetupApiWrapper.SetupDiGetDriverInfoDetail(
                            DevInfo,
                            DeviceInfoData,
                            DriverInfoData,
                            ref DriverInfoDetailData,
                            DriverInfoDetailData.cbSize,
                            ref reqSize);

Answer 1

oAlthough I agree that the error code seems unexpected, I think the problem is that cbSize should be set to sizeof(SP_DRVINFO_DETAIL_DATA) (that’s the proper C sizeof, not Marshal.SizeOf on your p/invoke structure.)

A quick test with a two line C program gives:

ANSI 797
UNICODE 1570

For the two proper sizeof values (you need to work out which one you need yourself…)

In contrast Marshal.SizeOf(typeof(SP_DRVINFO_DETAIL_DATA)) for your structure gives 1048 as a length.

I think you need to get that lined up before you go any further.

I suspect that it might be that the buffer-too-small error is returned if DriverInfoDetailDataSize is too small, but the invalid-buffer error is returned if cbSize is wrong.

The help for SetupDiGetDriverInfoDetail is also explicit that cbSize and DriverInfoDetailDataSize are not supposed to be the same value (because ANYSIZE_ARRAY is just defined as 1 as a placeholder), so you should not expect to get Marshal.SizeOf to work correctly with your deliberately oversized structure.

Additional correction:

Your InfFilename member is also the wrong length – a structure which exactly matches the structure from SETUPAPI.H is:

    [StructLayout(LayoutKind.Sequential, Pack = 1, CharSet=CharSet.Unicode)]
    internal struct SP_DRVINFO_DETAIL_DATA
    {
        public Int32 cbSize;
        public System.Runtime.InteropServices.ComTypes.FILETIME InfDate;
        public Int32 CompatIDsOffset;
        public Int32 CompatIDsLength;
        public IntPtr Reserved;
        [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 256)]
        public String SectionName;
        [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 260)]
        public String InfFileName;
        [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 256)]
        public String DrvDescription;
        [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 1)]
        public String HardwareID;
    };

This gives the correct lengths, both in the ANSI and UNICODE versions. However, you don’t want to use this as-is, because you need HardwareID to be longer, so you’ll have to adjust the length of that and then live with Marshal.SizeOf giving the wrong value for plugging directly into cbSize.