Virus Scan Engine API

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This topic describes the API that is required for building a compliant Virus Scan Engine (VSE) for scanning and cleaning documents in Windows SharePoint Services 3.0. For a general introduction to the VSE and its requirements, see Overview: Virus Scan Engine API Implementation.

IMso_VirusScanner Interface

The following table describes the methods that are provided by the IMso_VirusScanner interface.

Remarks

The host application instantiates an IMso_VirusScanner object and performs the following tasks:

• Instantiates the virus scanner as an INPROC_SERVER in a free-threaded apartment.

• Calls the Initialize method prior to calling any other method.

• Ensures that there are no outstanding Scan requests prior to calling Release.

• Makes simultaneous calls to Scan or Clean from multiple threads after the Initialize method has completed and before calling Release.

The compliant scanner is an instance of the IMso_VirusScanner interface and performs the following tasks:

• All initialization and resource allocation through the Initialize method.

• NO calls to any operating system APIs with uncertain completion time during scanning or cleaning. Examples include, but are not limited to, file I/O and registry manipulation.

Initialize Method

Performs all per-instance initialization of the scanner and returns information about the current IMso_VirusScanner instance.

Syntax

STDMETHOD Initialize (
      BSTR *pbstrProduct,
      DWORD *pdwProductVersion
);

Parameters

Return Value

Success: Returns S_OK if initialization succeeds.

Failure: Returns an error code.

Remarks

This method must be called once per IMso_VirusScanner instance, immediately after the instance is created, and before any calls to the Scan or Clean method.

Scan Method

Scans content and returns infection status and virus information if available.

Syntax

STDMETHOD Scan (
      ILockBytes *pilb,
      DWORD *pdwStatus,
      BSTR *pbstrVirusInfo
);

Parameters

The host frees the returned value by using the SysFreeString function.

Return Value

Success: Returns S_OK if the operation completed successfully and the pdwStatus and pbstrVirusInfo parameters contain valid information.

Failure: Returns an error code.

Remarks

The host calls this method from several threads simultaneously. The scanner is expected to perform requests simultaneously without internal serialization of the requests.

Clean Method

Attempts to remove the virus infection from the content.

Syntax

STDMETHOD Clean (
      ILockBytes *pilbInput,
      ILockBytes *pilbOutput,
      DWORD *pdwStatus,
      BSTR *pbstrVirusInfo
);

Parameters

The host frees the returned value by using the SysFreeString function.

Return Value

Success: Returns S_OK if the operation completed successfully and the pdwStatus, wzVirusInfo, and pilbOutput parameters contain valid information.

Remarks

The host calls this method from several threads simultaneously. The scanner is expected to perform requests simultaneously without internal serialization of requests.

ILockBytes Interface

The ILockBytes interface is exposed to allow the vendor to extract extra information about the file, which can include the file name, file type, file size, and so on. For a complete description of this interface on MSDN, see ILockBytes.

Syntax

typedef struct tagSTATSTG {
      LPWSTR pwcsName;
      DWORD type;
      ULARGE_INTEGER cbSize;
      FILETIME mtime;
      FILETIME ctime;
      FILETIME atime;
      DWORD grfMode;
      DWORD grfLocksSupported;
      CLSID clsid;
      DWORD grfStateBits;
      DWORD reserved;
} STATSTG;

Members