Name: Flávio Cruz

Email: flaviocruz at gmail dot com

Some Hurd stuff

And code: cl-hurd

Summer session

Creating an extensible translator library in lisp using the mig generated stubs.

What's done

• The library for writing translators is mostly written.
• This library is intended to implement virtual filesystems. Examples are: translators were data is located in a local file (like zipfs, tarfs, rarfs, ...), single file translators (that do content filtering, output of a command, etc), network based filesystems (ftpfs, httpfs, ...), proxy filesystems (like hostmux, usermux, etc..)
• It's possible to specialize the basic translator library and implement new translator classes. This is done using CLOS.
• There is a tree-translator class that makes the managing of a node tree very easy, doing all the work for us, through a simple directory API and implementing the directory callbacks for us.
• There is a simple example (something like zipfs) translator that can expose the directories and file contents of a ZIP file.
• More translator examples include:
  • /dev/null translator.
  • /dev/zero translator.
  • translator that creates a symlink node.
  • tmpfs like translator.
  • a translator that does proxying between clients and the underlying translator returning all data in upper-case.
  • a translator that watches for changes in a file describing the file system structure.
  • an IRC translator.
  • a categorizer translator: creates a virtual directory containing files listed in a file, each file is categorized with a script. For example, a script can output the music author (in an mp3 file) and then all files will be categorized by author.
• Translator options (manipulated through fsysopts) have a simple and easy to use API.
• All the Mach port manipulation API is available.
• It's possible to send and receive messages. Simple example:

  (let* ((spec-mixed (make-message-spec :fields '(:string :integer :char :string :integer :real)))
         (msg-mixed (make-message :spec spec-mixed))
         (port (port-allocate :right-receive)))
    (send-message msg-mixed :remote port :data (list "abc" 42 #\b "cba" 314 3.14))
    (receive-message msg-mixed :source port) ; This returns T on success.
    (get-message msg-mixed))) ; Returns '("abc" 42 #\b "cba" 314 3.14)

• New message types (like :string, :integer) can be implemented, providing a powerful extension mechanism.
• Creation of symlinks and symlink path resolution.
• Creation of character/block devices, fifos and sockets.
• Patch that opens stdin + stdout to /dev/null.
• Project has been separated into 5 ASDF installable systems:
  • hurd-common
  • mach
  • hurd
  • hurd-translator
  • tree-translator
• Test cases are now written.

What needs to be done

• Fix fsys-getroot (block happens in trivfs based translators, when they do RPC's to me when I call fsys_getroot to them) and fetch-root (for passive translators).
• Make the library multithreaded (blocked by the pthread conversion project and the unavailable thread support in CLISP)
• Use the socket stubs?
• More documentation

Project dependencies

• CLISP
• CFFI (apt-get installable)
• Flexi streams (apt-get installable)
• Trivial garbage (not in debian repositories)
• cl-zip (only needed for the zip translator)
• cl-irc (for the irc translator)

To do

Documentation

• Manually Bootstrapping a Translator

Translation

• Translate the Hurd website to Portuguese?

Completed tasks

Patches

• http://alioth.debian.org/tracker/index.php?group_id=30628&atid=410472
  • libsvg patch accepted.
• Adapted glibc patch (http://www.schwinge.homeip.net/~thomas/tmp/glibc-patches/0009-2007-07-22-version-of-init-first.c_vs.GCC4.1.patch.patch)
  • http://opensvn.csie.org/leic/hurd/patches/glibc-init-first.patch
• Patch to remove some GNUMach IPC warnings and minor cleanup:
  • http://opensvn.csie.org/leic/hurd/patches/gnumach-ipc-warnings.patch
• Website patches that correct some encountered typos:
  • http://opensvn.csie.org/leic/hurd/patches/hurd-talk-typo.patch

Documentation read

• GNU/Hurd User's Guide, an introduction to the important concepts and software of the GNU system, written for new users, AKA "GNUbies."
• Towards a New Strategy of OS Design, an architectural overview by Thomas Bushnell, BSG.
• The Hurd, a presentation by Marcus Brinkmann.
• The Hurd Hacking Guide.
• The GNU Mach Reference Manual
• The GNU Hurd Reference Manual
• The Unofficial GNU Mach IPC beginner's guide
• Mach IPC without MIG
• CFFI User's Manual

Before selection

• Uptime program in C and Lisp using CFFI.
• Hello translator.

Misc

Lisp implementations that run on Hurd

• Clisp
• ECL
• ?