Welcome to the Lounge

Sander Rossel wrote:

Ugh, horrible! We have an automated Jenkins build

raddevus wrote:

So I'm just curious. Does anyone know how this can even work? How can Visual Studio and/or Android Studio continue to work when the files they are attempting to create are too long?

Quote:

ERROR_INVALID_NAME

123 (0x7B)

The filename, directory name, or volume label syntax is incorrect.

Quote:

In the ANSI version of this function, the name is limited to MAX_PATH characters. To extend this limit to 32,767 wide characters, call the Unicode version of the function and prepend //?/ to the path. For more information, see Naming Files, Paths, and Namespaces.

Quote:

The shell and the file system have different requirements. It is possible to create a path with the Windows API that the shell user interface is not able to interpret properly.

raddevus wrote:

Well, that's probably because you have no experience developing apps.

Randor wrote:

You do realize that you are on a forum with old MSFT engineers from the operating systems group right in the CP Lounge?

Randor wrote:

The CreateFileW[^] function can absolutely create files with paths greater than MAX_PATH.

Output

3/8/2017 8:31:59 AM
Failed!
HRESULT: -2147024773 Error: 123
Seems to work..

[DllImport("kernel32.dll", SetLastError=true, CharSet=CharSet.Auto)]
public static extern SafeFileHandle CreateFileW(
   String lpFileName,
   EFileAccess dwDesiredAccess,
   EFileShare dwShareMode,
   IntPtr lpSecurityAttributes,
   ECreationDisposition dwCreationDisposition,
   EFileAttributes dwFlagsAndAttributes,
   IntPtr hTemplateFile);
   
    
   [DllImport("user32.dll", CharSet=CharSet.Auto)]
    static extern int MessageBoxW(IntPtr hWnd, String text, String caption, int options);

   
void Main()
{
	
	 MessageBoxW(IntPtr.Zero, @"\\?\c:\users\<username>\temp\superlongfilenameand1234567890thisoneisgoingintherecordbooks1234567890andwillprobablytoastthisentire1234567890thingandiwonderwhatitisgoing1234567890todowhenilookatthefiletest1234567890ThisIsGoingToGoOnForALongLongLongLongLongTimeIthink123456789012345678901234567890123456789012345678901234567890_2017_03_10_2.txt", "Caption", 0);
	
	Console.WriteLine(DateTime.Now);
	
	SafeFileHandle sfh = CreateFileW(@"\\?\c:\users\<username>\temp\superlongfilenameand1234567890thisoneisgoingintherecordbooks1234567890andwillprobablytoastthisentire1234567890thingandiwonderwhatitisgoing1234567890todowhenilookatthefiletest1234567890ThisIsGoingToGoOnForALongLongLongLongLongTimeIthink123456789012345678901234567890123456789012345678901234567890_2017_03_10_2.txt", 
		EFileAccess.GenericWrite, EFileShare.Read, 
		IntPtr.Zero, ECreationDisposition.CreateAlways,
		EFileAttributes.Archive, IntPtr.Zero);
	if (sfh.IsInvalid ){
		Console.WriteLine("Failed!");
		int HRESULT = Marshal.GetHRForLastWin32Error();
		int ERRORVAL = Marshal.GetLastWin32Error();
		Console.WriteLine(String.Format("HRESULT: {0} Error: {1}",HRESULT, ERRORVAL));
	}
	else{
		Console.WriteLine("Seems to work..");
	}
	sfh = CreateFileW(@"\\?\C:\Users\<username>\temp\notlongName_2017_03_11_2.txt", 
	EFileAccess.GenericWrite, EFileShare.Read, 
		IntPtr.Zero, ECreationDisposition.CreateAlways,
		EFileAttributes.Archive, IntPtr.Zero);
	if (sfh.IsInvalid ){
		Console.WriteLine("Failed!");
		int HRESULT = Marshal.GetHRForLastWin32Error();
		int ERRORVAL = Marshal.GetLastWin32Error();
		Console.WriteLine(String.Format("HRESULT: {0} Error: {1}",HRESULT, ERRORVAL));
	}
	else{
		Console.WriteLine("Seems to work..");
	}
}

public enum EFileAccess : uint
    {
        //
        // Standart Section
        //

        AccessSystemSecurity = 0x1000000,   // AccessSystemAcl access type
        MaximumAllowed = 0x2000000,     // MaximumAllowed access type

        Delete = 0x10000,
        ReadControl = 0x20000,
        WriteDAC = 0x40000,
        WriteOwner = 0x80000,
        Synchronize = 0x100000,

        StandardRightsRequired = 0xF0000,
        StandardRightsRead = ReadControl,
        StandardRightsWrite = ReadControl,
        StandardRightsExecute = ReadControl,
        StandardRightsAll = 0x1F0000,
        SpecificRightsAll = 0xFFFF,

        FILE_READ_DATA = 0x0001,        // file & pipe
        FILE_LIST_DIRECTORY = 0x0001,       // directory
        FILE_WRITE_DATA = 0x0002,       // file & pipe
        FILE_ADD_FILE = 0x0002,         // directory
        FILE_APPEND_DATA = 0x0004,      // file
        FILE_ADD_SUBDIRECTORY = 0x0004,     // directory
        FILE_CREATE_PIPE_INSTANCE = 0x0004, // named pipe
        FILE_READ_EA = 0x0008,          // file & directory
        FILE_WRITE_EA = 0x0010,         // file & directory
        FILE_EXECUTE = 0x0020,          // file
        FILE_TRAVERSE = 0x0020,         // directory
        FILE_DELETE_CHILD = 0x0040,     // directory
        FILE_READ_ATTRIBUTES = 0x0080,      // all
        FILE_WRITE_ATTRIBUTES = 0x0100,     // all

        //
        // Generic Section
        //

        GenericRead = 0x80000000,
        GenericWrite = 0x40000000,
        GenericExecute = 0x20000000,
        GenericAll = 0x10000000,

        SPECIFIC_RIGHTS_ALL = 0x00FFFF,
        FILE_ALL_ACCESS =
        StandardRightsRequired |
        Synchronize | 
        0x1FF,

        FILE_GENERIC_READ =
        StandardRightsRead |
        FILE_READ_DATA |
        FILE_READ_ATTRIBUTES |
        FILE_READ_EA |
        Synchronize,

        FILE_GENERIC_WRITE =
        StandardRightsWrite |
        FILE_WRITE_DATA |
        FILE_WRITE_ATTRIBUTES |
        FILE_WRITE_EA |
        FILE_APPEND_DATA |
        Synchronize,

        FILE_GENERIC_EXECUTE = 
        StandardRightsExecute |
          FILE_READ_ATTRIBUTES |
          FILE_EXECUTE |
          Synchronize
    }
	
	[Flags]
public enum EFileAttributes : uint
{
   Readonly         = 0x00000001,
   Hidden           = 0x00000002,
   System           = 0x00000004,
   Directory        = 0x00000010,
   Archive          = 0x00000020,
   Device           = 0x00000040,
   Normal           = 0x00000080,
   Temporary        = 0x00000100,
   SparseFile       = 0x00000200,
   ReparsePoint     = 0x00000400,
   Compressed       = 0x00000800,
   Offline          = 0x00001000,
   NotContentIndexed= 0x00002000,
   Encrypted        = 0x00004000,
   Write_Through    = 0x80000000,
   Overlapped       = 0x40000000,
   NoBuffering      = 0x20000000,
   RandomAccess     = 0x10000000,
   SequentialScan   = 0x08000000,
   DeleteOnClose    = 0x04000000,
   BackupSemantics  = 0x02000000,
   PosixSemantics   = 0x01000000,
   OpenReparsePoint = 0x00200000,
   OpenNoRecall     = 0x00100000,
   FirstPipeInstance= 0x00080000
}

[Flags]
public enum EFileShare : uint
{
   /// <summary>
   /// 
   /// </summary>
   None = 0x00000000,
   /// <summary>
   /// Enables subsequent open operations on an object to request read access. 
   /// Otherwise, other processes cannot open the object if they request read access. 
   /// If this flag is not specified, but the object has been opened for read access, the function fails.
   /// </summary>
   Read = 0x00000001,
   /// <summary>
   /// Enables subsequent open operations on an object to request write access. 
   /// Otherwise, other processes cannot open the object if they request write access. 
   /// If this flag is not specified, but the object has been opened for write access, the function fails.
   /// </summary>
   Write = 0x00000002,
   /// <summary>
   /// Enables subsequent open operations on an object to request delete access. 
   /// Otherwise, other processes cannot open the object if they request delete access.
   /// If this flag is not specified, but the object has been opened for delete access, the function fails.
   /// </summary>
   Delete = 0x00000004
}

public enum ECreationDisposition : uint
{
   /// <summary>
   /// Creates a new file. The function fails if a specified file exists.
   /// </summary>
   New = 1,
   /// <summary>
   /// Creates a new file, always. 
   /// If a file exists, the function overwrites the file, clears the existing attributes, combines the specified file attributes, 
   /// and flags with FILE_ATTRIBUTE_ARCHIVE, but does not set the security descriptor that the SECURITY_ATTRIBUTES structure specifies.
   /// </summary>
   CreateAlways = 2,
   /// <summary>
   /// Opens a file. The function fails if the file does not exist. 
   /// </summary>
   OpenExisting = 3,
   /// <summary>
   /// Opens a file, always. 
   /// If a file does not exist, the function creates a file as if dwCreationDisposition is CREATE_NEW.
   /// </summary>
   OpenAlways = 4,
   /// <summary>
   /// Opens a file and truncates it so that its size is 0 (zero) bytes. The function fails if the file does not exist.
   /// The calling process must open the file with the GENERIC_WRITE access right. 
   /// </summary>
   TruncateExisting = 5
}

raddevus wrote:

What Do You Think?Can you explain this?

Randor wrote:

1.) You are using some invalid/reserved characters in your path. The < and > are reserved characters.

\\?\c:\users\<username>\temp\superlongfilenameand1234567890thisoneisgoingintherecordbooks1234567890andwillprobablytoastthisentire1234567890thingandiwonderwhatitisgoing1234567890todowhenilookatthefiletest1234567890ThisIsGoingToGoOnForALongLongLongLongLongTimeIthink123456789012345678901234567890123456789012345678901234567890_2017_03_10_2.txt

Randor wrote:

2.) You are incorrectly assuming that you can make a really long directory entry of 32,767 characters.

Randor wrote:

3.) You are mistakenly attempting to create directories with the CreateFile Function[^]

raddevus wrote:

Finally, I actually am following those rules. Do you have any other ideas?

Randor wrote:

Wow, you wrote a disk monitoring application but did not know about NTFS filename limits? How is that even possible? Are you a .NET coder or something?

Randor wrote:

You could always create files longer than MAX_PATH ... even on Windows NT 4 all you do is prefix them with the "\\?\"

Quote:

lpFileName [in]
The name of the file or device to be created or opened. You may use either forward slashes (/) or backslashes (\) in this name.
In the ANSI version of this function, the name is limited to MAX_PATH characters. To extend this limit to 32,767 wide characters, call the Unicode version of the function and prepend "\\?\" to the path.

raddevus wrote:

Plus read the exact wording on lpFileName (not path) at the Microsoft docs:

Quote:

lpFileName [in]The name of the file or device to be created or opened. You may use either forward slashes (/) or backslashes (\) in this name.In the ANSI version of this function, the name is limited to MAX_PATH characters. To extend this limit to 32,767 wide characters, call the Unicode version of the function and prepend "\\?\" to the path.

Randor wrote:

I can see why this is unclear. Keep in mind that you can use CreateFile to open COM ports and various other devices.

\\?\C:\Users\<username>\temp\12345678901234567890\12345678901234567890\12345678901234567890\12345678901234567890\12345678901234567890\12345678901234567890\12345678901234567890\12345678901234567890\12345678901234567890\12345678901234567890\abcdefghijklmnopqrstuvwxzy1234abcdefghijklmnopqrstuv\X_abcdefghijklmnopqrstuvwxyz1234abcdefghijklmnopqrstuvwxyz1234abcdefghijklmnopqrstuvwxyz1234abcdefghijklmnopqrstuvwxyz1234abcdefghijklmnopqrstuvwxyz1234abcdefghijklmnopqrstuvwxyz1234abcdefghijklmnopqrstuvwxyz1234abcdefghijklmnopqrstuvwxyz1234_X\Y_abcdefghijklmnopqrstuvwxyz1234abcdefghijklmnopqrstuvwxyz1234abcdefghijklmnopqrstuvwxyz1234abcdefghijklmnopqrstuvwxyz1234abcdefghijklmnopqrstuvwxyz1234abcdefghijklmnopqrstuvwxyz1234abcdefghijklmnopqrstuvwxyz1234abcdefghijklmnopqrstuvwxyz1234_Y/superlongfilenamean12henilookatthefiletest1234567890ThisIsGoingToGoOnForALongLongLongLongLongTimeIthink1234567890123456789012superlongfilenamean12henilookatthefiletest1234567890ThisIsGoingToGoOnForALongLon345678901234567890123456789012345_2017_03_10_3.txt

C:\Users\ROGER~1.DEU\temp\123456~1\123456~1\123456~1\123456~1\123456~1\123456~1\123456~1\123456~1\123456~1\123456~1\ABCDEF~1\X_ABCD~1\Y_ABCD~1

raddevus wrote:

Explorer won't let me copy the path out though -- ends up using the tilde names like:

C:\Users\ROGER~1.DEU\temp\123456~1\123456~1\123456~1\123456~1\123456~1\123456~1\123456~1\123456~1\123456~1\123456~1\ABCDEF~1\X_ABCD~1\Y_ABCD~1