Significant remote file system improvements

[matt335672]

• Reimplemented inode store in separate module chansrv_xfs.[hc]
• Allowed atimes and mtimes to be written to Windows side
• Mapped directory/file user write bit to (inverted) Windows FILE_ATTRIBUTE_READONLY bit
• Mapped file user execute bit to Windows FILE_ATTRIBUTE_SYSTEM bit
• Implemented improved security for remotely mounted drives (see man sesman.ini)
• Implemented USB device removal, allowing hot-plug/remove of memory sticks
• Fixed pagefile.sys (etc) breaking Ubuntu file browser
• Fixed write offset bug
• Allowed renaming of open files
• Improved reported error codes
• Fixed various memory leaks
• Removed hardcoded buffer sizes where appropriate
• Addressed valgrind/memcheck errors related to struct fuse_file_info pointers.

This improves the remote filesystem support to a point where it can even be used to support an XRDP build, although it is necessary to disable PAM support for this, as instfiles/pam.d/mkpamrules creates a soft-link which isn't supported. I used the following commands on an Ubuntu 18.04 LTS system with the XRDP 0.9.11 release tarball:-

cd ~/thinclient_drives/C\:/Users/mjb/Documents/
tar xf ~/xrdp-0.9.11.tar.gz
cd xrdp-0.9.11
./configure --enable-pixman --enable-fuse --disable-pam
make

There are a lot of code changes here. I've tried to simplify the code where possible to make it easier to follow. A lot of private stuff has been moved out of devredir.h into other places. primarily the new includes ms-erref.h, ms-fscc.h, ms-rdpefs.h and ms-smb2.h. The separate inode store in chansrv_xfs.c is significantly faster than the previous inode store, and removes a lot of complications from the code paths in chansrv_fuse.c.

[metalefty]

Brilliant! You really make lots of contributions on drive redirection. I trust your QA. Let's ship it to the next v0.9.12 release.

[matt335672]

Thanks for vote of confidence!

I've got a question for you. I've created four new includes ms-erref.h, ms-fscc.h, ms-rdpefs.h and ms-smb2.h in the chansrv directory containing definitions from the relevant MS docs. I did this to remove unnecessary definitions from devredir.h.

These includes could be merged with common/xrdp_constants.h, or alternatively some of the constants in common/xrdp_constants.h could be moved out to new files common/ms-rdpbcgr.h and common/ms-rdpegdi.h to slim it down a bit. It's just a bit of tidying up.

Let me know which you prefer and I'll put a separate PR together after Xmas.

[metalefty]

The latter plan sounds tidy and clear which constants come from which MS document for me.
+1 to the latter.