[Bug 56647] New: ntdll-Junction_Points prevent rustup from correctly installing a toolchain

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=56647

Bug ID: 56647
           Summary: ntdll-Junction_Points prevent rustup from correctly
                    installing a toolchain
           Product: Wine-staging
           Version: 9.8
          Hardware: x86-64
               URL: https://rustup.rs/
                OS: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: -unknown
          Assignee: [e-mail]
          Reporter: [e-mail]
                CC: [e-mail], [e-mail]
      Distribution: ArchLinux

Created attachment 76423
  --> https://bugs.winehq.org/attachment.cgi?id=76423
return STATUS_NOT_A_REPARSE_POINT instead of STATUS_INVALID_PARAMETER

Hi.
With the recent rustup 1.27.0 using wine-staging  with the
ntdll-Junction_Points patches, the toolchain installation doesn't complete
properly, failing to write to the settings.toml under the prefix home .rustup
directory info.

A bug with the same root cause is also present on rustup 1.26.0 where while the
installation was completing properly, it was failing to remove the
.rustup/tmp/* directories, causing issues with subsequent installations.

Both bugs express the same behavioral pattern with few differences. I
investigated the directory bug firstly, so I will detail this, and confirmed
that the problem and the expected solution are the same.

Rustup (or one of it's dependency managing files) get the handle of the
temporary directory using CreateFileW and then checking if it's a reparse point
using DeviceIoControl with FSCTL_GET_REPARSE_POINT.
The directories (and the file) aren't reparse points at all, so the readlink
fails returining EINVAL.
This EINVAL is then mapped to an NT_STATUS using errno_to_status that map
EINVAL to STATUS_INVALID_PARAMETER. 
However this mapping is incorrect for FSCTL_GET_REPARSE_POINT as in this case
applications that handle this case  like rustup try to handle this case by
epxecting STATUS_NOT_A_REPARSE_POINT.

Returning STATUS_NOT_A_REPARSE_POINT in this case allow rustup to work (both
versions )

Attaching a patch to show the change in the file.c code (and restored also the
out_buffer check)