cklutz/lockcheck

Uses platform APIs to find processes locking one or multiple files (Windows - Restart Manager or NTDLL)

lockcheck's Issues

Check against working directories of all running processes

I've learned an interesting thing today:

you can't delete a directory which is a working directory of some running process on Windows. So if you get Access Denied when trying to delete a directory, check for a running process whose current directory is it.

We should consider extending LockCheck to iterate over running processes and check if there's a process whose current directory is the one we're asking about (or a subdirectory thereof).

Windows NtDll.cs requires `FILE_FLAG_BACKUP_SEMANTICS` for directories

Current behaviour

GetLockingProcessInfos with LockManagerFeatures.UseLowLevelApi does not work if the path is a directory on windows.
The simplest example is getting the locks of a directory that is the working directory of a cmd/powershell window.

Environment info

Windows 10 x64 on .NET 7

Possible solution

I've found this line from the documentation:
https://learn.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-createfilea

Flag	Meaning
FILE_FLAG_BACKUP_SEMANTICS 0x02000000	You must set this flag to obtain a handle to a directory. A directory handle can be passed to some functions instead of a file handle. For more information, see the Remarks section.

And then later in the same docs:

To open a directory using CreateFile, specify the FILE_FLAG_BACKUP_SEMANTICS flag as part of dwFlagsAndAttributes. Appropriate security checks still apply when this flag is used without SE_BACKUP_NAME and SE_RESTORE_NAME privileges.

So I think we should be using this flag if the path is a directory 👍

Other notes

I would be interested to know how this compares to the approach mentioned by @KirillOsenkov in #6. The only case I can think of is that it would also be able to find locks on children of the directory, whereas this approach would not. Finding the lock of a child of a directory seems to be outside the scope of this library though.

Additionally, Restart Manager seems to not support finding locks on directories. Seems like another problem, but I thought I would mention it here.

I am interested in fixing it here because I'm currently using my fork of LockCheck in https://github.com/domsleee/ForceOps. For directories, I am currently just using NtDll (with UseLowLevelApi).