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133 lines
3.8 KiB
C
133 lines
3.8 KiB
C
/*
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* PROJECT: ReactOS Sound System "MME Buddy" Library
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* LICENSE: GPL - See COPYING in the top level directory
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* FILE: lib/drivers/sound/mmebuddy/kernel.c
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*
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* PURPOSE: Routines assisting with device I/O between user-mode and
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* kernel-mode.
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*
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* PROGRAMMERS: Andrew Greenwood (silverblade@reactos.org)
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*/
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#include "precomp.h"
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/*
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Wraps around CreateFile in order to provide a simpler interface tailored
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towards sound driver support code. This simply takes a device path and
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opens the device in either read-only mode, or read/write mode (depending on
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the ReadOnly parameter).
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If the device is opened in read/write mode, it is opened for overlapped I/O.
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*/
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MMRESULT
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OpenKernelSoundDeviceByName(
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IN PWSTR DevicePath,
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IN BOOLEAN ReadOnly,
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OUT PHANDLE Handle)
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{
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DWORD AccessRights;
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VALIDATE_MMSYS_PARAMETER( DevicePath );
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VALIDATE_MMSYS_PARAMETER( Handle );
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AccessRights = ReadOnly ? GENERIC_READ : GENERIC_READ | GENERIC_WRITE;
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SND_TRACE(L"OpenKernelSoundDeviceByName: %wS\n", DevicePath);
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*Handle = CreateFile(DevicePath,
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AccessRights,
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FILE_SHARE_WRITE, /* FIXME? Should be read also? */
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NULL,
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OPEN_EXISTING,
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ReadOnly ? 0 : FILE_FLAG_OVERLAPPED,
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NULL);
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if ( *Handle == INVALID_HANDLE_VALUE )
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{
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SND_ERR(L"CreateFile filed - winerror %d\n", GetLastError());
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return Win32ErrorToMmResult(GetLastError());
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}
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return MMSYSERR_NOERROR;
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}
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/*
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Just a wrapped around CloseHandle.
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*/
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MMRESULT
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CloseKernelSoundDevice(
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IN HANDLE Handle)
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{
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VALIDATE_MMSYS_PARAMETER( Handle );
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CloseHandle(Handle);
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return MMSYSERR_NOERROR;
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}
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/*
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This is a wrapper around DeviceIoControl which provides control over
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instantiated sound devices. It waits for I/O to complete (since an
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instantiated sound device is opened in overlapped mode, this is necessary).
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*/
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MMRESULT
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SyncOverlappedDeviceIoControl(
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IN HANDLE Handle,
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IN DWORD IoControlCode,
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IN LPVOID InBuffer,
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IN DWORD InBufferSize,
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OUT LPVOID OutBuffer,
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IN DWORD OutBufferSize,
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OUT LPDWORD BytesTransferred OPTIONAL)
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{
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OVERLAPPED Overlapped;
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BOOLEAN IoResult;
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DWORD Transferred;
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/* Overlapped I/O is done here - this is used for waiting for completion */
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ZeroMemory(&Overlapped, sizeof(OVERLAPPED));
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Overlapped.hEvent = CreateEvent(NULL, FALSE, FALSE, NULL);
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if ( ! Overlapped.hEvent )
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return Win32ErrorToMmResult(GetLastError());
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/* Talk to the device */
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IoResult = DeviceIoControl(Handle,
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IoControlCode,
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InBuffer,
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InBufferSize,
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OutBuffer,
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OutBufferSize,
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NULL,
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&Overlapped);
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/* If failure occurs, make sure it's not just due to the overlapped I/O */
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if ( ! IoResult )
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{
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if ( GetLastError() != ERROR_IO_PENDING )
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{
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CloseHandle(Overlapped.hEvent);
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return Win32ErrorToMmResult(GetLastError());
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}
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}
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/* Wait for the I/O to complete */
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IoResult = GetOverlappedResult(Handle,
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&Overlapped,
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&Transferred,
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TRUE);
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/* Don't need this any more */
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CloseHandle(Overlapped.hEvent);
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if ( ! IoResult )
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return Win32ErrorToMmResult(GetLastError());
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SND_TRACE(L"Transferred %d bytes in Sync overlapped I/O\n", Transferred);
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if ( BytesTransferred )
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*BytesTransferred = Transferred;
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return MMSYSERR_NOERROR;
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}
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