Re: [ros-dev] [ros-diffs] [hbelusca] 74619: [USETUP]: filesup module: - Add a NtPathToDiskPartComponents helper, that takes in input a fully qualified NT path to a file on hard disk, e.g.: \Device\Harddisk1\Partition2\foo\b...

[Thomas Faber]

On 2017-05-22 01:45, [e-mail] wrote:
> +BOOLEAN
> +NtPathToDiskPartComponents(
> IN PCWSTR NtPath,
> OUT PULONG pDiskNumber,
> OUT PULONG pPartNumber,
> OUT PCWSTR* PathComponent OPTIONAL)
>
> +{
> ULONG DiskNumber, PartNumber;
> PCWSTR Path;
> *pDiskNumber = 0;
> *pPartNumber = 0;
> if (PathComponent) *PathComponent = NULL;
> Path = NtPath;
> if (_wcsnicmp(Path, L"\Device\Harddisk", 16) != 0)
> {
>    /* The NT path doesn't start with the prefix string, thus it cannot be a hard disk device path */
>    DPRINT1("'%S' : Not a possible hard disk device.\n", NtPath);
>    return FALSE;
> }
> Path += 16;

Avoiding these magic numbers would be nice.
Options include:
* static string à la
  static const WCHAR DeviceHarddiskPath[] = L"\Device\Harddisk";
  _wcsnicmp(Path, DeviceHarddiskPath, ARRAYSIZE(DeviceHarddiskPath) - 1)
* simply using wcslen(L"\Device\Harddisk") (which should get optimized)
* making a "starts with" function
* using RtlPrefixUnicodeString
> @@ -593,6 +705,31 @@
>       {
>           DPRINT1("Failed to open file %wZ, Status 0x%08lx\n", &Name, Status);
>           return Status;
> }
> if (FileSize)
> {
>    /* Query the file size */
>    FILE_STANDARD_INFORMATION FileInfo;
>    Status = NtQueryInformationFile(*FileHandle,
>                                    &IoStatusBlock,
>                                    &FileInfo,
>                                    sizeof(FileInfo),
>                                    FileStandardInformation);
>    if (!NT_SUCCESS(Status))
>    {
>        DPRINT("NtQueryInformationFile() failed (Status %lx)\n", Status);
>        NtClose(*FileHandle);
>        *FileHandle = NULL;
>        return Status;
>    }
>    if (FileInfo.EndOfFile.HighPart != 0)
>        DPRINT1("WARNING!! The file %wZ is too large!\n", Name);

Did you mean &Name?

[Hermès BÉLUSCA-MAÏTO]

Hi,
> > if (_wcsnicmp(Path, L"\Device\Harddisk", 16) != 0)
> > {
> >    /* The NT path doesn't start with the prefix string, thus it cannot be a hard disk device path */
> >    DPRINT1("'%S' : Not a possible hard disk device.\n", NtPath);
> >    return FALSE;
> > }
> > Path += 16;
> Avoiding these magic numbers would be nice.
> Options include:
> static string à la
> static const WCHAR DeviceHarddiskPath[] = L"\Device\Harddisk";
> _wcsnicmp(Path, DeviceHarddiskPath, ARRAYSIZE(DeviceHarddiskPath) - 1)
> simply using wcslen(L"\Device\Harddisk") (which should get optimized)
> making a "starts with" function
> using RtlPrefixUnicodeString

Yes, I may choose the RtlPrefix one but these options are better.
> >    if (FileInfo.EndOfFile.HighPart != 0)
> >        DPRINT1("WARNING!! The file %wZ is too large!\n", Name);
> Did you mean &Name?

Correct