Merge branch 'master' of flubber:~hurd-web/hurd-web

7 files changed, 1920 insertions, 805 deletions

diff --git a/user/jkoenig/d-i.mdwn b/user/jkoenig/d-i.mdwn
new file mode 100644
index 00000000..0b9f9f7d
--- /dev/null
+++ b/user/jkoenig/d-i.mdwn
@@ -0,0 +1,358 @@
+[[!meta copyright="Copyright © 2010 Free Software Foundation, Inc."]]
+
+[[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable
+id="license" text="Permission is granted to copy, distribute and/or modify this
+document under the terms of the GNU Free Documentation License, Version 1.2 or
+any later version published by the Free Software Foundation; with no Invariant
+Sections, no Front-Cover Texts, and no Back-Cover Texts.  A copy of the license
+is included in the section entitled [[GNU Free Documentation
+License|/fdl]]."]]"""]]
+
+## Hurd Debian-Installer
+
+My [proposal](http://wiki.debian.org/SummerOfCode2010/HurdDebianInstaller/JeremieKoenig)
+to work on porting d-i on Hurd
+as a [Google Summer of Code](http://code.google.com/soc/) student
+has been accepted by the Debian project.
+
+I will be keeping track of my progress on this page.
+
+### Links
+
+  * [Modified packages](http://jk.fr.eu.org/debian/unstable)
+  * [Latest images](http://jk.fr.eu.org/debian/hurd-installer)
+  * [Debian bugs](http://bugs.debian.org/cgi-bin/pkgreport.cgi?users=jk@jk.fr.eu.org&tag=gsoc2010)
+  * [BusyBox port](http://lists.debian.org/debian-bsd/2010/05/msg00048.html)
+  * [GNU Mach initrd](http://lists.gnu.org/archive/html/bug-hurd/2010-06/msg00047.html)
+
+### Roadmap
+
+* **mach**: initrd support
+    * (./) preliminary patch posted and self-built (2010-06-12)
+    * adjustments will be needed (postponed)
+    * consider the alternatives discussed on bug-hurd (postponed)
+
+* **glibc**: fix `mkdir("/")` which returned `EINVAL`
+    * (./) eglibc 2.11.2-1 includes a quick fix by youpi (2010-06-15)
+    * (./) more complete patch posted to bug-hurd,
+      since other calls return incorrect errors under some circumstances
+      (2010-06-16)
+    * more work on it will be needed to make it fix the whole thing
+      (postponed)
+
+* (./) **partman** (2010-06-23)
+    * (./) add hurd-i386 to
+      `partman-partitioning/lib/disk-label.sh`
+      (2010-06-16, commited by youpi on 2010-06-23)
+    * (./) short-circuit
+      `partman-basicfilesystems/init.d/kernelmodules_basicfilesystems`
+      (2010-06-16)
+    * (./) partman-auto recipes:
+      make the default filesystem os-dependent
+      when it has not been preseeded (ie. the *seen* flag is clear)
+    * (./) force 4k blocks and 128 bytes inodes
+    * (./) submit patches to bugs.debian.org
+      ([[!debbug 586870]] and [[!debbug 586871]])
+    * (./) rebuild with responsible version numbers and upload to my repository
+
+* (./) **libparted** (2010-06-23)
+    * (./) fix device paths ([[!debbug 586696]])
+    * (./) fix crash on exit for part:* stores ([[!debbug 586682]])
+
+* **hurd-udeb** (2010-06-23)
+    * (./) rebuild with the hack suggested by youpi for qemu network configuration
+    * (./) fix mount to accept `-o defaults`
+    * cleanup, ask youpi to commit
+
+* reloading the partition table (2010-06-25)
+    * User-space part stores
+        * (./) hurd-udeb now uses `part:N:device:X` for partition devices
+          (2010-06-23)
+        * (./) it also provides /lib/partman/commit.d/??hurd\_reloadpart,
+          which basically does `settrans -ag /dev/[hs]d*`.
+          (2010-06-24)
+    * Kernel-based partition devices
+        * (./) Mach's drivers from Linux support reloading partitions.
+          With help from youpi this has been made available through a
+          device\_set\_status() call.
+        * (./) make libparted use it
+        * Reminder:
+          I should file a bug against libparted with the patch sometime.
+
+* (./) The `/servers/exec` issue (2010-06-26)
+    * Due to /servers being inexistant,
+      the bootstrap ext2fs could not register the initial exec server,
+      meaning that non-bootstrap filesystems used a different one
+      (started from the passive translator),
+      which for some reason died on shell scripts, making them stall.
+    * Adding the `/servers` directory to hurd-udeb fixed it,
+      as well as the /hurd/proc issue
+      (failed to be run by init the first time around).
+    * Reminder: report the non-bootstrap exec servers failure on scripts.
+
+* (./) **base-installer**: (2010-06-26)
+    * Work around non-existant /proc/mounts.
+    * Firmlink /servers into /target after debootstrap
+      to make the network available.
+
+* (./) **grub-installer**
+    * (./) add hurd support (2010-06-27)
+    * /!\ grub-legacy still needs to be tested
+    * submit changes as a Debian bug
+
+**Milestone (2010-06-28):
+installer kindof works, with documented manual intervention required**
+
+* (./) Sort out the situation with dev node creation (2010-07-07):
+    * Devices and servers used to be set up by debootstrap;
+      the hurd package would add some missing nodes.
+    * New strategy implemented in hurd and debootstrap:
+        * debootstrap uses active firmlinks into the host system
+          for the target system's /dev and /servers.
+        * the hurd package now include a `setup-translators` script,
+          which is used to register the passive translators by the installer's
+          `/libexec/runsystem` and hurd's postinst script.
+
+* **busybox**: submit upstream and to [[!debbug 323670]]
+  (waiting for upstream to review)
+    * (./) I have mentioned my work on the upstream mailing list,
+    * (./) merge the recent changes from upstream,
+      notably to the build system.
+      (2010-06-23)
+    * (./) ask upstream for review and merge
+      (2010-06-25)
+    * (./) sent as patches as requested
+      (2010-07-08)
+    * (./) backport any additional changes onto the debian branch
+    * (./) hijack [[!debbug 323670]] and submit my patches
+
+* **aptitude**:
+    * Currently broken on hurd-i386:
+      [[!debpkg gtest]] fails to build because of a segfault in one of the test
+      cases, [[!debpkg google-mock]] and hence [[!debpkg aptitude]] are missing
+      it as a build-dep.
+      The older package is not installable anymore because it's linked against
+      an older version of libept, which has been removed.
+    * (./) I bypassed the tests and uploaded the 3 packages to my repository
+      (2010-07-08)
+    * The segfault will have to be sorted out. (postponed)
+
+* (./) "Fix" the swap situation. (2010-07-08)
+    * The device\_close() libstore patch
+      had the unfortunate effect of making swapon fail,
+      since the device it activates has to be kept open.
+    * add options for MAKEDEV and setup-devices
+      to use the libparted stores
+    * disable youpi's patch
+    * make partman-basicfilesystems re-create the device
+      as a kernel partition, which is needed for swapon
+
+* (./) netcfg-static: port to hurd (2010-07-09)
+    * There was some amount of hurd support already
+      (namely, activating the interface by replacing the socket translator)
+    * However, this code started an active translator with
+      di\_exec\_shell\_log("settrans -a ...),
+      which stalled as a consequence of it capturing libdi's pipe
+      as its standard output.
+    * Network devices must be probed by trying to open Mach devices
+      with predetermined names (currently eth%d, wl%d),
+      because getifaddrs() does not seem to work on Hurd.
+    * /!\ netcfg, and configuring the installed system, postponed.
+
+* **procps** 3.2.7-11 (current hurd-i386 version) has [[!debbug 546888]]
+    * (./) Submit [[!debbug 588677]] and upload the result to my repository.
+      (2010-07-11)
+
+* (./) Set up a Debian mirror with modified packages for installation
+    * the [mirror](http://jk.fr.eu.org/debian/hurd-install/mirror)
+      is now up and running (2010-07-06)
+    * hacked the image build script to include its public key in
+      debian-archive-keyring at image build time (2010-07-08)
+    * Apparently debootstrap does not handle multiple versions very well.
+      Fix by using dpkg-scan{package,sources} rather than apt-ftparchive
+      to create index files.
+      (2010-07-10)
+    * Use the override files from ftp.debian.org,
+      to avoid debootstrap grabbing inappropriate packages.
+    * Changed them to make [[!debpkg ifupdown]],
+      [[!debpkg dhcp3-client]] and [[!debpkg dhcp3-client]] priority extra,
+      because they're uninstallable at the moment.
+      (2010-07-12)
+
+* (./) Put together a "jk-archive-keyring" package,
+  so that the mirror is authenticated in the target system as well.
+  (2010-07-12)
+
+* (./) Fix grub for user-space partitions (2010-07-16)
+    * grub-probe detects the whole device rather than the partition
+      as the device behind /boot/grub.
+      Consequently, grub-install fails.
+    * One approach would be to replace /dev/hd* by kernel devices
+      for file systems as well as for swap partitions.
+      > {X} this makes the installer crash,
+      > possibly due to cache coherency issue between hdX and hdXsY.
+
+    * (./) GRUB2 kern/emu/getroot.c
+      [patched](http://lists.gnu.org/archive/html/bug-hurd/2010-07/msg00059.html)
+      to support part stores.
+
+* (./) Fix finish-install to skip `finish-install.d/90console` on Hurd
+  (2010-07-17)
+
+* (./) Avoid starting unnecessary /dev translators in a burst (2010-07-20)
+  * Use debootstrap use the extracted /usr/lib/hurd/setup-translators
+    to create device and server nodes in /target,
+    then firmlink the whole /target/dev and /target/servers
+    to the outer system.
+  * Make hurd.postinst not touch them on initial install.
+
+* (./) Fix mach-defpager for file and part stores on larger devices
+  * Use DEVICE\_GET\_RECORDS instead of DEVICE\_GET\_SIZE, which overflows an int
+    (2010-07-22)
+
+**Milestone (2010-07-22):
+installer works but it's still somewhat ugly and broken**
+
+* (./) Ship the UTF-8 font for the hurd console
+  (2010-07-22)
+  * Upload a version of bogl with youpi's patch for Hurd.
+    (see [[!debbug 589987]])
+  * Fix the hurd console for fonts with 16 pixels wide glyphs
+    (ie. handle the 8-wide glyph in there correclty)
+  * Support double-width glyphs (2010-07-24)
+  * (./) However the reduced font can't be loaded yet,
+    so make installer/build/Makefile
+    ship the whole `/usr/src/unifont.bgf`
+    as `/usr/share/hurd/vga-system.bgf`.
+
+* (./) Make the installer used the extended capabilities of the Hurd console
+  (2010-07-23)
+  * Set an UTF-8 locale in `/lib/debian-installer.d/S41term-hurd`.
+  * localechooser: set the language display level to 3
+    when using the hurd console.
+
+* (./) **busybox**: cross-platform package uploaded to experimental
+  (2010-08-03?)
+  * Aurelien Jarno updated the packaging to busybox 1.17.1,
+    fixed a whole lot of bugs,
+    and uploaded a new package with both our changes;
+  * most patches adopted upstream, and included in the new package;
+  * (u)mount/swaponoff ported to kFreeBSD;
+  * per-OS configuration overrides.
+
+* (./) Update custom packages to the latest versions
+  and send updated patches to the BTS
+  (2010-08-11)
+    * updated partman-base to choose a default filesystem in debian/rules
+      rather than at runtime,
+      as suggested by Aurelien Jarno in [[!debbug 586870]]
+    * patch submitted for debian-installer-utils
+      ([[!debbug 592684]]).
+    * patch submitted for locale-chooser
+      ([[!debbug 592690]]).
+    * debootstrap, grub-installer and finish-install not yet submitted,
+      since the details may still change.
+
+* (./) **partman-target**: fix fstab creation
+  (2010-08-11)
+  * See [[!debbug 592671]]
+  * debian/rules: set `partman/mount_style` to `traditional` on Hurd.
+  * finish.d/create\_fstab\_header: add a Hurd case.
+
+* (./) **rootskel**: FTBFS on Hurd and other quirks
+  (to be fixed very soon)
+
+* **d-i/installer/build**: (expected soon)
+    * publish the patch I use
+    * sort out the changes suitable for inclusion
+      and ask youpi and/or debian-boot@l.d.o to commit them
+
+* call for testing and fix the bugs
+
+* Bug in setup-translators/MAKEDEV:
+  permissions are broken for nodes re-created through `MAKEDEV -k`,
+  because MAKEDEV's chmod/chown reaches the pre-existing translator
+    * Maybe settrans could be made to accept -o/--owner and
+      -p/--perm, to set the permissions for the underlying node?
+
+* (./) Silence the "no kernel" warning somehow.
+
+* Investigate the wget/libc/pfinet/whatever bug which corrupts Packages.gz,
+  see the IRC log for 2010-07-23, around 1am UTC+0200 
+
+* Try to resolve problems with udebs which are uninstallable on hurd-i386,
+  such as installation-locale and partman-whatever.
+
+* Provide `/proc/cmdline -> 2/cmdline`, or something.
+
+* Prepare a NMU for genext2fs (which is orphaned),
+  and ask youpi to sponsor the upload.
+
+* **busybox**: port 
+    * fix stty/stat/ipcs on kFreeBSD,
+    * generally port more stuff,
+    * *ip* is needed (maybe) for network configuration,
+    * *mount*, *swaponoff* can be from hurd-udeb for now,
+      though the kFreeBSD people will need them
+
+* **partman**: further adjustments
+    * partman-base: handle /dev/hd?s* in lib/base.h
+    * hide irrelevant mount options? (sync, relatime)
+
+* Network configuration on the installed system.
+  This includes porting ifupdown and isc-dhcp-client,
+  which are currently uninstallable on hurd-i386.
+* Also, better DHCP support during and after installation
+
+* improve the [initrd situation](FIXME: link to bug-hurd post):
+  ajust the ramdisk support in Mach,
+  use tmpfs if possible.
+
+* mklibs{,-copy}:
+  test library reduction,
+  make it copy the ld.so -> ld.so.1 symlink.
+
+* (./) hurd console fonts
+
+**Milestone (expected 2010-07-19):
+it works great and it's beautiful**
+
+* test, fix, document
+* support more types of installation images
+* give a shot at the graphical installer if time permits
+* integrate wireless drivers with netcfg
+* see how [[zhengda]]'s work on DDE could be integrated
+* etc..
+
+### Mostly done
+
+#### Week 1 (2010-05-24)
+
+* genext2fs: patches submitted, [[!debbug 562999]]
+  which add support for all block sizes and choosing them at runtime.
+* busybox: started porting the upstream and Debian package to Hurd and FreeBSD
+* rebuilding hurd-udeb from the pkg-hurd version
+  and adding a ld.so link to the initrd
+  fixes the exec translator crashing on startup.
+  (BTW would there be a mean to detect this from the libdiskfs bootstrap code
+  and report it ?)
+
+#### Week 2 (2010-05-31 to 2010-06-06)
+
+* *busybox*: patches [posted](http://lists.debian.org/debian-bsd/2010/05/msg00048.html).
+* *libdebian-installer4*: [[!debbug 584538]]
+* started working on mach initrd support
+* the installation images could boot into the main-menu
+  with the following changes:
+      * rebuild hurd-udeb from with the latest pkg-hurd patches
+      * use busybox from my osports-debian branch (see link above)
+      * tweak the d-i image build scripts
+      * the symlink /lib/ld.so -> ld.so.1 needs to be created somehow
+        (youpi mentionned it being the job of libc0.3-udeb I think)
+      * fix the poll() issue in libdebian-installer
+        (patch to be submitted soon),
+        also there is some hurd doxygen short-circuiting stuff
+        there which does not apply any more and prevents is to build.
+      * feed the initrd as a hard drive in qemu
+        (with some more space added to avoid it from becoming full)
+
diff --git a/user/jkoenig/gsoc2011_proposal.mdwn b/user/jkoenig/gsoc2011_proposal.mdwn
index 4052f455..9840f14f 100644
--- a/user/jkoenig/gsoc2011_proposal.mdwn
+++ b/user/jkoenig/gsoc2011_proposal.mdwn
@@ -1,628 +1,12 @@
+[[!meta copyright="Copyright © 2010 Free Software Foundation, Inc."]]
 
-# Java for Hurd (and vice versa)
+[[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable
+id="license" text="Permission is granted to copy, distribute and/or modify this
+document under the terms of the GNU Free Documentation License, Version 1.2 or
+any later version published by the Free Software Foundation; with no Invariant
+Sections, no Front-Cover Texts, and no Back-Cover Texts.  A copy of the license
+is included in the section entitled [[GNU Free Documentation
+License|/fdl]]."]]"""]]
 
-Contact information:
-
-  * Full name: Jérémie Koenig
-  * Email: jk@jk.fr.eu.org
-  * IRC: jkoenig on Freenode and OFTC
-
-## Introductions
-
-I am a first year M.Sc. student
-in Computer Science at University of Strasbourg (France).
-My interests include capability-based security,
-programming languages and formal methods
-(in particular, object-capability languages and proof-carrying code).
-
-### Proposal summary
-
-This project would consist in improving Java support on Hurd.
-The first part would consist in
-fixing bugs and porting Java-related packages.
-The second part would consist in
-creating low-level Java bindings for the Hurd interfaces,
-as well as libraries to make translator development easier.
-
-### Previous involvement
-
-I started contributing to Hurd last summer,
-during which I participated to Google Summer of Code
-as a student for the Debian project.
-I worked on porting Debian-Installer to Hurd.
-This project was mostly a success,
-although we still have to use a special mirror for installation
-with a few modified packages
-and tweaked priorities
-to work around some uninstallable packages
-with Priority: standard.
-
-Shortly afterwards,
-I rewrote the procfs translator
-to fix some issues with memory leaks,
-make it more reliable,
-and improve compatibility with Linux-based tools
-such as `procps` or `htop`.
-
-Although I have not had as much time
-as I would have liked to dedicate to the Hurd
-since that time,
-I have continued to maintain the mirror in question,
-and I have started to work
-on implementing POSIX threads signal semantics in glibc.
-
-### Project-related skills and interests
-
-I have used Java mostly for university assignments.
-This includes non-trivial projects
-using threads and distributed programming frameworks
-such as Java RMI or CORBA.
-I have also used it to experiment with
-Google App Engine
-(web applications)
-and Google Web Toolkit
-(a compiler from Java to Javascript which helps with AJAX code),
-and I have some limited experience with JNI
-(the Java Native Interface, to link Java with C code).
-
-My knowledge of the Hurd and Debian GNU/Hurd is reasonable,
-as the Debian-Installer and procfs projects
-gave me the opportunity to fiddle with many parts of the system.
-
-Initially,
-I started working on this project because I wanted to use
-[Joe-E](http://code.google.com/p/joe-e/)
-(a subset of Java)
-to investigate the potential
-[[applications of object-capability languages|objcap]]
-in a Hurd context.
-I also believe that improving Java support on Hurd
-would be an important milestone.
-
-### Organisational matters
-
-I am subscribed to bug-hurd@g.o and
-I do have a permanent internet connexion.
-
-I would be able to attend the regular IRC meetings,
-and otherwise communicate with my mentor
-through any means they would prefer
-(though I expect email and IRC would be the most practical).
-Since I'm already familiar with the Hurd,
-I don't expect I would require too much time from them.
-
-My exams end on May 20 so I would be able to start coding
-right at the beginning of the GSoC period.
-Next year's term would probably begin around September 15,
-so that would not be an issue either.
-I expect I would work around 40 hours per week,
-and my waking hours would be flexible.
-
-I don't have any other plans for the summer
-and would not make any if my project were to be accepted.
-
-Full disclosure:
-I also submitted a proposal to the Jikes RVM project
-(which is a research-oriented Java Virtual Machine,
-itself written in Java)
-for implementing a new garbage collector into the MMTk subsystem.
-
-## Improve Java support
-
-### Justification
-
-Java is a popular language and platform used by many desktop and web
-applications (mostly on the server side). As a consequence, competitive Java
-support is important for any general-purpose operating system.
-Better Java support would also be a prerequisite
-for the second part of my proposal.
-
-### Current situation
-
-Java is currently supported on Hurd with the GNU Java suite:
-
-   * [GCJ](http://gcc.gnu.org/java/),
-     the GNU Compiler for Java, is part of GCC and can compile Java
-     source code to Java bytecode, and both source code and bytecode to
-     native code;
-   * libgcj is the implementation of the Java runtime which GCJ uses.
-     It is based on [GNU Classpath](http://www.gnu.org/software/classpath/).
-     It includes a bytecode interpreter which enables
-     Java applications compiled to native code to dynamically load and execute
-     Java bytecode from class files.
-   * The gij command is a wrapper around the above-mentioned virtual machine
-     functionality of libgcj and can be used as a replacement for the java
-     command.
-
-However, GCJ does not work flawlessly on Hurd.r
-For instance, some parts of libgcj relies on
-the POSIX threads signal semantics, which are not yet implemented.
-In particular, this makes ant hang waiting for child processes,
-which makes some packages fail to build on Hurd
-(“ant” is the “make” of the Java world).
-
-### Tasks
-
-   * **Finish implementing POSIX thread semantics** in glibc (high priority).
-     According to POSIX, signal dispositions should be global to a process,
-     while signal blocking masks should be thread-specific. Signals sent to the
-     process as a whole are to be delivered to any thread which does not block
-     them. By contrast, Hurd has per-thread signal dispositions and signals
-     sent to a process are delivered to the main thread only. I have been
-     working on refactoring the glibc signal code and implementing the POSIX
-     semantics as a per-thread option. However, due to lack of time I have not
-     yet been able to test and debug my code properly. Finishing this work
-     would be my first task.
-   * **Fix further problems with GCJ on Hurd** (high priority). While I’m not
-     aware of any other problems with GCJ at the moment, I suspect some might
-     turn up as I progress with the other tasks. Fixing these problems would
-     also be a high-priority task.
-   * **Port OpenJDK 6** (medium priority). While GCJ is fine, it is not yet
-     100% complete. It is also slower than OpenJDK on architectures where a
-     just-in-time compiler is available. Porting OpenJDK would therefore
-     improve Java support on Hurd in scope and quality. Besides, it would also
-     be a good way to test GCJ, which is used for bootstrapping by the Debian
-     OpenJDK packages. Also note that OpenJDK 6 is now the default Java
-     Runtime Environment on all released Linux-based Debian architectures;
-     bringing Hurd in line with this would probably be a good thing.
-   * **Port Eclipse and other Java applications** (low priority). Eclipse is a
-     popular, state-of-the-art IDE and tool suite used for Java and other
-     languages. It is a dependency of the Joe-E verifier (see part 3 of this
-     proposal). Porting Eclipse would be a good opportunity to test GCJ and
-     OpenJDK.
-
-### Deliverables
-
-  * The glibc pthreads patch and any other fixes on the Hurd side
-    would be submitted upstream
-  * Patches against Debian source packages
-    required to make them build on Hurd would be submitted
-    to the [Debian bug tracking system](http://bugs.debian.org/).
-
-
-## Create Java bindings for the Hurd interfaces
-
-### Justification
-
-Java is used for many applications and often taught to
-introduce object-oriented programming. The fact that Java is a
-garbage-collected language makes it easier to use, especially for the less
-experienced programmers. Besides, its object-oriented nature is a
-natural fit for the capability-based design of Hurd.
-The JVM is also used as a target for many other languages,
-all of which would benefit from the access provided by these bindings.
-
-Advantages over other garbage-collected, object-oriented languages include
-performance, type safety and the possibility to compile a Java translator to
-native code and
-[link it statically](http://gcc.gnu.org/wiki/Statically_linking_libgcj)
-using GCJ, should anyone want to use a
-translator written in Java for booting.
-Note that Java is
-[being](http://www.linuxjournal.com/article/8757)
-[used](http://oss.readytalk.com/avian/)
-in this manner for embedded development.
-Since GCJ can take bytecode as its input,
-this expect this possibility would apply to any JVM-based language.
-
-Java bindings would lower the bar for newcomers
-to begin experimenting with what makes Hurd unique
-without being faced right away with the complexity of
-low-level systems programming.
-
-### Tasks summary
-
-  * Implement Java bindings for Mach
-  * Implement a libports-like library for Java
-  * Modify MIG to output Java code
-  * Implement libfoofs-like Java libraries
-
-### Design principles
-
-The principles I would use to guide the design
-of these Java bindings would be the following ones:
-
-  * The system should be hooked into at a low level,
-    to ensure that Java is a "first class citizen"
-    as far as the access to the Hurd's interfaces is concerned.
-  * At the same time, the memory safety of Java should be maintained
-    and extended to Mach primitives such as port names and
-    out-of-line memory regions.
-  * Higher-level interfaces should be provided as well
-    in order to make translator development
-    as easy as possible.
-  * A minimum amount of JNI code (ie. C code) should be used.
-    Most of the system should be built using Java itself
-    on top of a few low-level primitives.
-  * Hurd objects would map to Java objects.
-  * Using the same interfaces,
-    objects corresponding to local ports would be accessed directly,
-    and remote objects would be accessed over IPC.
-
-One approach used previously to interface programming languages with the Hurd
-has been to create bindings for helper libraries such as libtrivfs. Instead,
-for Java I would like to take a lower-level approach by providing access to
-Mach primitives and extending MIG to generate Java code from the interface
-description files.
-
-This approach would be initially more involved, and would introduces several
-issues related to overcoming the "impedance mismatch" between Java and Mach.
-However, once an initial implementation is done it would be easier to maintain
-in the long run and we would be able to provide Java bindings for a large
-percentage of the Hurd’s interfaces.
-
-### Bindings for Mach system calls
-
-In this low-level approach, my intention is to enable Java code to use Mach
-system calls (in particular, mach_msg) more or less directly. This would
-ensure full access to the system from Java code, but it raises a number of
-issues:
-
-  * the Java code must be able to manipulate Mach-level entities, such as port
-    rights or page-aligned buffers mapped outside of the garbage-collected
-    heap (for out-of-line transfers);
-  * putting together IPC messages requires control of the low-level
-    representation of data.
-
-In order to address these concerns, classes would be encapsulating these
-low-level entities so that they can be referenced through normal, safe objects
-from standard Java code. Bindings for Mach system calls can then be provided
-in terms of these classes. Their implementation would use C code through the
-Java Native Interface (JNI).
-
-More specifically, this functionality would be provided by the `org.gnu.mach`
-package, which would contain at least the following classes:
-
-  * `MachPort` would encapsulate a `mach_port_t`. (Some of) its constructors
-    would act as an interface for the `mach_port_allocate()` system call.
-    `MachPort` objects would also be instantiated from other parts of the JNI
-    C code to represent port rights received through IPC. The `deallocate()`
-    method would call `mach_port_deallocate()` and replace the encapsulated
-    port name with `MACH_PORT_DEAD`. We would recommend that users call it
-    when a port is no longer used, but the finalizer would also deallocate the
-    port when the `MachPort` object is garbage collected.
-  * `Buffer` would represent a page-aligned buffer allocated outside of the
-    Java heap, to be transferred (or having been received) as out-of-line
-    memory. The JNI code would would provide methods to read and write data at
-    an arbitrary offset (but within bounds) and would use `vm_allocate()` and
-    `vm_deallocate()` in the same spirit as for `MachPort` objects.
-  * `Message` would allow Java code to put together Mach messages. The
-    constructor would allocate a `byte[]` member array of a given size.
-    Additional methods would be provided to fill in or query the information
-    in the message header and additional data items, including `MachPort` and
-    `Buffer` objects which would be translated to the corresponding port names
-    and out-of-line pointers.
-    A global map from port names to the corresponding `MachPort` object
-    would probably be needed to ensure that there is a one-to-one
-    correspondence.
-  * `Syscall` would provide static JNI methods for performing system calls not
-    covered by the above classes, such as `mach_msg()` or
-    `mach_thread_self()`.  These methods would accept or return `MachPort`,
-    `Buffer` and `Message` objects when appropriate. The associated C code
-    would access the contents of such objects directly in order to perform the
-    required unsafe operations, such as constructing `MachPort` and `Buffer`
-    objects directly from port names and C pointers.
-
-Note that careful consideration should be given to the interfaces of these
-classes to avoid “safety leaks” which would compromise the safety guarantees
-provided by Java. Potential problematic scenarios include the following
-examples:
-
-  * It must not be possible to write an integer at some position in a
-    `Message` object, and to read it back as a `MachPort` or `Buffer` object,
-    since this would allow unsafe access to arbitrary memory addresses and
-    mach port names.
-  * Providing the `mach_task_self()` system call would also provide access to
-    arbitrary addresses and ports by using the `vm_*` family of RPC operations
-    with the returned `MachPort` object. This means that the relevant task
-    operations should be provided by the `Syscall` class instead.
-
-Finally, access should be provided to the initial ports and file descriptors
-in `_hurd_ports` and provided by the `getdport()` function,
-for instance through static methods such as
-`getCRDir()`, `getCWDir()`, `getProc()`, ... in a dedicated class such as
-`org.gnu.hurd.InitPorts`.
-
-A realistic example of code based on such interfaces would be:
-
-    import org.gnu.mach.MsgType;
-    import org.gnu.mach.MachPort;
-    import org.gnu.mach.Buffer;
-    import org.gnu.mach.Message;
-    import org.gnu.mach.Syscall;
-    import org.gnu.hurd.InitPorts;
-
-    public class Hello
-    {   
-       public static main(String argv[])
-           /* Parent class for all Mach-related exceptions */
-           throws org.gnu.mach.MachException
-       {   
-           /* Allocate a reply port */
-           MachPort reply = new MachPort();
-
-           /* Allocate an out-of-line buffer */
-           Buffer data = new Buffer(MsgType.CHAR, 13);
-           data.writeString(0, "Hello, World!");
-
-           /* Craft an io_write message */
-           Message msg = new Message(1024);
-           msg.setRemotePort(InitPorts.getdport(1));
-           msg.setLocalPort(reply, Message.Type.MAKE_SEND_ONCE);
-           msg.setId(21000);
-           msg.addBuffer(data);
-
-           /* Make the call, MACH_MSG_SEND | MACH_MSG_RECEIVE */
-           Syscall.machMsg(msg, true, true, reply);
-
-           /* Extract the returned value */
-           msg.assertId(21100);
-           int retCode = msg.readInt(0);
-           int amount = msg.readInt(1);
-       }
-    }
-
-Should this paradigm prove insufficient,
-more ideas could be borrowed from the
-[`org.vmmagic`](http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.151.5253&rep=rep1&type=pdf)
-package used by [Jikes RVM](http://jikesrvm.org/),
-a research Java virtual machine itself written in Java.
-
-### Generating Java stubs with MIG
-
-Once the basic machinery is in place to interface with Mach, Java programs
-have more or less equal access to the system functionality without resorting
-to more JNI code. However, as illustrated above, this access is far from
-convenient.
-
-As a solution I would modify MIG to add the option to output Java code. MIG
-would emit a Java interface, a client class able to implement the interface
-given a Mach port send right, an a server class which would be able to handle
-incoming messages. The class diagram below, although it is by no means
-complete or exempt of any problem, illustrates the general idea:
-
-[[gsoc2011_classes.png]]
-
-This structure is somewhat reminiscent of
-[Java RMI](http://en.wikipedia.org/wiki/Java_remote_method_invocation)
-or similar systems,
-which aim to provide more or less transparent access to remote objects.
-The exact way the Java code would be generated still needs to be determined,
-but basically:
-
-  * An interface, corresponding to the header files generated by MIG, would
-    enumerate the operations listed in a given .defs files. Method names would
-    be transformed to adhere to Java conventions (for instance,
-    `some_random_identifier` would become `someRandomIdentifier`).
-  * A user class, corresponding to the `*User.c` files,
-    would implement this interface by doing RPC over a given MachPort object.
-  * A server class, corresponding to `*Server.c`, would be able to handle
-    incoming messages using a user-provided implementation of the interface.
-    (Possibly, a skeleton class providing methods which would raise
-    `NotImplementedException`s would be provided as well.
-    Users would derive from this class and override the relevant methods.
-    This would allow them not to implement some operations,
-    and would avoid pre-existing code from breaking when new operations are
-    introduced.)
-
-In order to help with the implementation of servers, some kind of library
-would be needed to associate Mach receive rights with server objects and to
-handle incoming messages on dedicated threads, in the spirit of libports.
-This would probably require support for port sets at the level of the Mach
-primitives described in the previous section.
-
-When possible, operations involving the transmission of send rights
-of some kind would be expressed in terms of the MIG-generated interfaces
-instead of `MachPort` objects.
-Upon reception of a send right,
-a `FooUser` object would be created
-and associated with the corresponding `MachPort` object.
-If the received send right corresponds to a local port
-to which a server object has been associated,
-this object would be used instead.
-This way,
-subsequent operations on the received send right
-would be handled as direct method calls
-instead of going through RPC mechanisms.
-
-Some issues will still need to be solved regarding how MIG will convert
-interface description files to Java interfaces. For instance:
-
-  * `.defs` files are not explicitly associated with a type. For instance in
-    the example above, MIG would have to somehow infer that io_t corresponds
-    to `this` in the `Io` interface.
-  * More generally, a correspondence between MIG and Java types would have
-    to be determined. Ideally this would be automated and not hardcoded
-    too much.
-  * Initially, reply port parameters would be ignored. However they may be
-    needed for some applications.
-
-So the details would need to be flushed out during the community bonding
-period and as the implementation progresses. However I’m confident that a
-satisfactory solution can be designed.
-
-Using these new features, the example above could be rewritten as:
-
-    import org.gnu.hurd.InitPorts;
-    import org.gnu.hurd.Io;
-    import org.gnu.hurd.IoUser;
-
-    class Hello {
-       static void main(String argv[]) throws ...
-       {
-           Io stdout = new IoUser(InitPorts.getdport(1));
-           String hello = “Hello, World!\n”;
-
-           int amount = stdout.write(hello.getBytes(), -1);
-
-           /* (A retCode corresponding to an error
-               would be signalled as an exception.) */
-       }
-    }
-
-An example of server implementation would be:
-
-    import org.gnu.hurd.Io;
-    import java.util.Arrays;
-
-    class HelloIo implements Io {
-       final byte[] contents = “Hello, World!\n”.getBytes();
-
-       int write(byte[] data, int offset) {
-           return SOME_ERROR_CODE;
-       }
-
-       byte[] read(int offset, int amount) {
-           return Arrays.copyOfRange(contents, offset,
-                                     offset + amount - 1);
-       }
-
-       /* ... */
-    }
-
-A new server object could then be created with `new IoServer(new HelloIo())`,
-and associated with some receive right at the level of the ports management
-library.
-
-### Base classes for common types of translators
-
-Once MIG can target Java code, and a libports equivalent is available,
-creating new translators in Java would be greatly facilitated. However,
-we would probably want to introduce basic implementations of file system
-translators in the spirit of libtrivfs or libnetfs. They could take the form
-of base classes implementing the relevant MIG-generated interfaces which
-would then be derived by users,
-or could define a simpler interface
-which would then be used by adapter classes
-to implement the required ones.
-
-I would draw inspiration from libtrivfs and libnetfs
-to design and implement similar solutions for Java.
-
-### Deliverables
-
-  * A hurd-java package would contain the Java code developed
-    in the context of this project.
-  * The Java code would be documented using javadoc
-    and a tutorial for writing translators would be written as well.
-  * Modifications to MIG would be submitted upstream,
-    or a patched MIG package would be made available.
-
-The Java libraries resulting from this work,
-including any MIG support classes
-as well as the class files built from the MIG-generated code
-for the Mach and Hurd interface definition files,
-would be provided as single `hurd-java` package for
-Debian GNU/Hurd.
-This package would be separate from both Hurd and Mach,
-so as not to impose unreasonable build dependencies on them.
-
-I expect I would be able to act as its maintainer in the foreseeable future, 
-either as an individual or as a part of the Hurd team.
-Hopefully,
-my code would be claimed by the Hurd project as their own,
-and consequently the modifications to MIG
-(which would at least conceptually depend on the Mach Java package)
-could be integrated upstream.
-
-Since by design,
-the Java code would use only a small number of stable interfaces,
-it would not be subject to excessive amounts of bitrot.
-Consequently,
-maintenance would primarily consist in
-fixing bugs as they are reported,
-and adding new features as they are requested.
-A large number of such requests
-would mean the package is useful,
-so I expect that the overall amount of work
-would be correlated with the willingness of more people
-to help with maintenance
-should I become overwhelmed or get hit by a bus.
-
-
-## Timeline
-
-The dates listed are deadlines for the associated tasks.
-
-  * *Community bonding period.*
-    Discuss, refine and complete the design of the Java bindings
-    (in particular the MIG and "libports" parts)
-  * *May 23.*
-    Coding starts.
-  * *May 30.*
-    Finish implementing pthread signal semantics.
-  * *June 5.*
-    Port OpenJDK
-  * *June 12.*
-    Fix the remaining problems with GCJ and/or OpenJDK,
-    possibly port Eclipse or other big Java packages.
-  * *June 19.*
-    Create the bindings for Mach.
-  * *June 26.*
-    Work on some kind of basic Java libports
-    to handle receive rights.
-  * *July 3.*
-    Test, write some documentation and examples.
-  * *July 17 (two weeks).*
-    Add the Java target to MIG.
-  * *July 24.*
-    Test, write some documentation and examples.
-  * *August 7 (two weeks).*
-    Implement a modular libfoofs to help with translator development.
-    Try to write a basic but non-trivial translator
-    to evaluate the performance and ease of use of the result,
-    rectify any rough edges this would uncover.
-  * *August 22. (last two weeks)*
-    Polish the code and packaging,
-    finish writing the documentation.
-
-
-## Conclusion
-
-This project is arguably ambitious.
-However, I have been thinking about it for some time now
-and I'm confident I would be able to accomplish most of it.
-
-In the event multiple language bindings projects
-would be accepted,
-some work could probably be done in common.
-In particular,
-[ArneBab](http://www.bddebian.com/~hurd-web/community/weblogs/ArneBab/2011-04-06-application-pyhurd/)
-seems to favor a low-level approach for his Python bindings as I do for Java,
-and I would be happy to discuss API design and coordinate MIG changes with him.
-I would also have an extra month after the end of the GSoC period
-before I go back to school,
-which I would be able to use to finish the project
-if there is some remaining work.
-(Last year's rewrite of procfs was done during this period.)
-
-As for the project's benefits,
-I believe that good support for Java
-is a must-have for the Hurd.
-Java bindings would also further the Hurd's agenda
-of user freedom by extending this freedom to more people:
-I expect the set of developers
-who would be able to write Java code against a well-written libfoofs
-is much larger than
-those who master the intricacies of low-level systems C programming.
-From a more strategic point of view,
-this would also help recruit new contributors
-by providing an easier path to learning the inner workings of the Hurd.
-
-Further developments
-which would build on the results of this project
-include my planned [[experiment with Joe-E|objcap]]
-(which I would possibly take on as a university project next year).
-Another possibility would be to reimplement some parts
-of the Java standard library
-directly in terms of the Hurd interfaces
-instead of using the POSIX ones through glibc.
-This would possibly improve the performance
-of some Java applications (though probably not by much),
-and would otherwise be a good project
-for someone trying to get acquainted with Hurd.
-
-Overall, I believe this project would be fun, interesting and useful.
-I hope that you will share this sentiment
-and give me the opportunity to spend another summer working on Hurd.
+This page has moved [[here|java]].
 
diff --git a/user/jkoenig/gsoc2011_proposal/discussion.mdwn b/user/jkoenig/gsoc2011_proposal/discussion.mdwn
deleted file mode 100644
index 0131d8d5..00000000
--- a/user/jkoenig/gsoc2011_proposal/discussion.mdwn
+++ /dev/null
@@ -1,180 +0,0 @@
-[[!meta copyright="Copyright © 2011 Free Software Foundation, Inc."]]
-
-[[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable
-id="license" text="Permission is granted to copy, distribute and/or modify this
-document under the terms of the GNU Free Documentation License, Version 1.2 or
-any later version published by the Free Software Foundation; with no Invariant
-Sections, no Front-Cover Texts, and no Back-Cover Texts.  A copy of the license
-is included in the section entitled [[GNU Free Documentation
-License|/fdl]]."]]"""]]
-
-Some [[tschwinge]] comments regarding your proposal.  Which is very good, if I
-may say so again!  :-)
-
-Of course, everyone is invited to contribute here!
-
-I want to give the following methodology a try, instead of only having
-email/IRC discussions -- for the latter are again and again showing a tendency
-to be dumped and deposited into their respective archives, and be forgotten
-there.  Of course, email/IRC discussions have their usefulness too, so we're
-not going to replace them totally.  For example, for conducting discussions
-with a bunch of people (who may not even be following these pages here), email
-(or, as applicable, the even more interactive IRC) will still be the medium of
-choice.  (And then, the executive summary should be posted here, or
-incorporated into your proposal.)
-
-Also, if you disagree with this suggested procedure right away, or at some
-later point begin to feel that this thing doesn't work out, or simply takes too
-much time (I don't think so: writing emails takes time, too), just say so, and
-we can reconsider.
-
-Of course, as this wiki is a passive medium rather than an active one as IRC
-and email are, it is fine to send notices like: *I have updated the wiki page,
-please have a look*.
-
-One idea is that your proposal evolves alongside with the ongoing work, and
-represents (in more or less detail) what has been done and what will be done.
-Also, we can hopefully use parts of it for documentation purposes, or as
-recipes for similar work (enabling other programming languages on the Hurd, for
-example).
-
-For this, I suggest the following procedure: as applicable, you can either
-address any comments in here (for example, if they're wrong :-), or if they
-require further discussion; think: *email discussion*), or you can address them
-directly in your propoal and remove the comments from here at the same time
-(think: *bug fix*).
-
-Generally, you can assume that for things I didn't comment on (within some
-reasonable timeframe/upon asking me again) that I'm fine with them.  Otherwise,
-I might say: *I don't like this as is, but I'll need more time to think about
-it.*
-
-There is also a possibility that parts of your proposal will be split off; in
-cases where we think they're valuable to follow, but not at this time.  (As you
-know, your proposal is not really a trivial one, so it may just be too much for
-one person's summer.)  Such bits could be moved to [[open_issues]] pages,
-either new ones or existing ones, as applicable.
-
-
-# POSIX Threads Signal Semantics
-
-  * Great!  [[tschwinge]] had a brief look, and should have a deeper one.
-
-  * If [[jkoenig]] thinks it's mature enough: should ask Samuel to test this
-    (that is, only the refactoring patches for starters?) on the buildds.
-
-  * Then: should ask Roland to review.
-
-  * Documentations bits should probably be moved to [[glibc/signal]].
-
-
-## libthreads (cthreads) Integration
-
-  * [[tschwinge]] suggests to leave them as-is?
-
-
-## [[libpthread]] integration
-
-  * To be done.
-
-
-# Java
-
-  * [[tschwinge]] has to read about RMI and CORBA.
-
-
-# Joe-E
-
-  * For later.
-
-
-# GCJ
-
-  * [[tschwinge]] has the feeling that Java in GCC (that is, GCJ) is mostly
-    dead?  (True?)
-
-  * Thus perhaps not too much effort should be spent with it.
-
-    If the POSIX threads signal semantics makes it going, then great, otherwise
-    we should get a feeling what else is missing.
-
-
-# OpenJDK
-
-  * All in all, [[tschwinge]] has the feeling that a working OpenJDK will be
-    more useful/powerful than GCJ.
-
-  * We need to get a feeling how difficult such an OS port will be.
-
-  * [[jkoenig]] suggests OpenJDK 6 -- should we directly go for version 7
-    instead?
-
-      * What are the differences (regarding the OS port) between the two
-        versions?  Or this there something even more recent to be worked upon,
-        for new OS ports?
-
-          * Perhaps the different versions' OS port specific stuff is not at
-            all very different, so that both v6 and v7 could be done?
-
-  * They seem to have a rather heavy-weight process for such projects: confer
-    <http://mail.openjdk.java.net/pipermail/announce/2011-January/000092.html>,
-    for example.  Do we need this, too?
-
-
-# Eclipse
-
-OK for testing -- but I'd very much hope that it *just works* as soon as we
-provide the required Java platform.
-
-
-# Java Bindings
-
-
-## Design Principles
-
-  * Generally ack.
-
-
-### MIG
-
-  * Hacking [[microkernel/mach/MIG]] shouldn't be too difficult.
-
-      * (Unless you want to make MIG's own code (that is, not the generated
-        code, but MIG itself) look a bit more nice, too.)  ;-)
-
-  * There are also alternatives to MIG.  If there is interest, the following
-    could be considered:
-
-      * FLICK ([[!GNU_Savannah_task 5723]]).  [[tschwinge]] has no idea yet if
-        there would be any benefits over MIG, like better modularity (for the
-        backends)?  If we feel like it, we could spend a little bit of time on
-        this.
-
-      * For [[microkernel/Viengoos]], Neal has written a RPC stub generator
-        entirely in C Preprocessor macros.  While this is obviously not
-        directly applicable, perhaps we can get some ideas from it.
-
-      * Anything else that would be worth having a look at?  (What are other
-        microkernels using?)
-
-
-### `mach_msg`
-
-  * Seems like the right approach to [[tschwinge]], but hasn't digested all the
-    pecularities yet.  Will definitely need more time.
-
-
-# GSoC Site Discussion
-
-  * Discussion items from
-    <http://www.google-melange.com/gsoc/proposal/review/google/gsoc2011/jkoenig/1>
-    should be copied here:
-
-      * technical bits (obviously);
-
-      * also the *why do we want Java bindings* reasoning;
-
-      * CLISP findings should also be documented somewhere permanently.
-
-          * We should probaby open up a *languages for Hurd* section on the web
-            pages ([[!taglink open_issue_documentation]]).
diff --git a/user/jkoenig/java.mdwn b/user/jkoenig/java.mdwn
new file mode 100644
index 00000000..700f9c4e
--- /dev/null
+++ b/user/jkoenig/java.mdwn
@@ -0,0 +1,321 @@
+[[!meta copyright="Copyright © 2011 Free Software Foundation, Inc."]]
+
+[[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable
+id="license" text="Permission is granted to copy, distribute and/or modify this
+document under the terms of the GNU Free Documentation License, Version 1.2 or
+any later version published by the Free Software Foundation; with no Invariant
+Sections, no Front-Cover Texts, and no Back-Cover Texts.  A copy of the license
+is included in the section entitled [[GNU Free Documentation
+License|/fdl]]."]]"""]]
+
+# Improve Java on Hurd (GSoC 2011)
+
+
+## Description
+
+The project consists in improving Java support on Hurd.
+This includes porting OpenJDK,
+creating low-level Java bindings for Mach and Hurd,
+as well as creating Java libraries to help with translator development.
+
+For details, see my original [[proposal]].
+
+
+## Current status
+
+Feeling slightly behind schedule; but project is very ambitious, which has been
+known from the beginning, and there is great progress, so there is no problem.
+--[[tschwinge]], 2011-06-29.
+
+[[tschwinge]] will be on vacations in China starting July 26th, will have
+Internet access intermittently, but not regularely.  We'll have to figure out
+some scheme.
+
+
+### Apt repository
+
+Modified Debian packages are available in this repository:
+
+    deb http://jk.fr.eu.org/debian experimental/
+    deb-src http://jk.fr.eu.org/debian experimental/
+
+
+### Glibc signal code improvements
+
+2011-06-29:
+Patches were submitted to `libc-alpha`
+which implement global signal dispositions and `SA_SIGINFO`.
+My latest code is available on
+[github](http://github.com/jeremie-koenig/glibc/commits/master-beware-rebase),
+and modified Debian packages
+are available in my apt repository.
+
+One question is how the new symbols introduced by my patches
+should be handled.
+Weak symbols turned out to be impractical,
+so I'm currently considering using a Debian-specific
+symbol version in the interim period (`GLIBC_2.13_DEBIAN_8` so far).
+The ultimate symbol version to be used will depend on
+the time at which the patches get integrated upstream
+(most likely `GLIBC_2.15`),
+at which point we will alias the interim version
+to the new one in debian packages.
+
+I have modified libc0.3 to include a `deb-symbols(5)` file
+(alternatively see <http://wiki.debian.org/Projects/ImprovedDpkgShlibdeps>)
+so that we get an accurate libc dependency in `hurd` and other packages
+when the symbols in question are pulled in.
+
+[[hurd/libthreads]] (cthreads library) will not be changed.  There's no reason
+why its behavior should change, whereas for [[libpthread]] it's needed for
+conformance.  Patches posted on 2011-05-25, but there's a more recent one in
+the modified hurd package (adds `_hurd_sigstate_delete` and removes the weak
+symbols).
+
+Another issue which came up with OpenJDK is the expansion
+by the dynamic linker of `$ORIGIN` in the `RPATH` header,
+see below.
+
+#### Plans
+
+The patches are pending review and inclusion upstream.
+As soon as we reach an agreement wrt. the new interfaces
+(in particular wrt. the value of `SA_SIGINFO`),
+the patches will be applied to the Debian libc packages
+for broader testing.
+
+
+##### Open Items
+
+  * Test patches: in progress, [[jkoenig]], Svante.  More volunteers welcome,
+    of course.
+
+    > There's an issue with gdb,
+    > namely signals lose their "untracedness" when they go
+    > through the global sigstate's pending mask,
+    > so gdb spins intercepting a signal and trying to deliver it.
+    > [Patch](http://github.com/jeremie-koenig/glibc/commit/3ecb990e9d08d5f75adc40b738b35a1802cc0943).
+
+  * If [[jkoenig]] thinks it's mature enough: should ask
+    [[Samuel|samuelthibault]] to test these patches on the buildds.
+
+    > There's a risk that a dependency on my patched libc
+    > might be pulled in while building packages
+    > (in particular hurd)
+    > --[[jkoenig]] 2011-06-22
+
+      * Waiting on ABI finalization ([!] Roland).
+
+          * Which numeric values to use for `SA_SIGINFO` (and `SA_NOCLDWAIT`)?
+
+            > Staying in sync with BSD seems the most logical approach,
+            > so I have defined it to 0x40. --[[jkoenig]] 2011-06-29
+
+  * Get patches reviewed (Roland?), and integrated into official sources: [!]
+    [[tschwinge]].
+
+    > [[samuelthibault]] reviewed the patches and pointed out a couple of
+    > issues which I'm currently working on:
+    >
+    >   * Slight behaviour change with respect to forgetting blocked ignored
+    >     signals. POSIX is flexible in this regard but I guess we could retain
+    >     them instead of the current behaviour.
+    >   * Sigstate accessors could be made extern inline functions.
+    >     I suggest we postpone this.
+    >   * Incorrect changes for `msg_{get,set}_init_int(INIT_SIGMASK)`
+    >   * Some comments which can be improved.
+    >
+    > Once these are fixed we can probably test the patches in Debian.
+    >
+    > --[[jk]] 2011-07-06
+
+  * Documentations bits (from here, the initial [[proposal]], and elsewhere)
+    should probably be
+    moved either into the appropriate glibc or Hurd documentation
+    files/reference manuals, or to [[glibc/signal]].
+
+  * `SA_SIGINFO` patch is based on [[Samuel|samuelthibault]]'s earlier work.
+    Thus, have him review the new patch?
+
+  * `SA_SIGINFO` patch has a few TODOs w.r.t. protocol changes for missing
+    information, and for FPU state.  Providing even incomplete information is
+    an improvement on the current status.  The question is, whether
+    applications rely on this information in any hard way if `SA_SIGINFO` is
+    available?
+
+      * We could possibly rename certain fields in `struct siginfo`, say
+        `si_pid_not_implemented`, to ensure compilation failures for programs
+        which use them.  Or perhaps a linker warning is possible.
+
+      * The FPU state is not included in the `ucontext_t` passed to the signal
+        handler.  On the other hand, `ucontext_t` is actually being somewhat
+        deprecated: the functions to restore it are no longer in POSIX.
+        `thread_get_state`() should return this information, in case we decide
+        to fill the gap, and there might be existing glibc wrappers, too.
+
+  * Perhaps have a look at `SA_NOCLDWAIT`.
+
+
+### Port OpenJDK
+
+As suggested by [[tschwinge]], I have targeted OpenJDK 7 at first.
+I don't expect it will be too hard to backport my patches to OpenJDK 6.
+I have succeeded in building a working JIT-less ("zero") version,
+although the dynamic linker issue must be worked around.
+Porting Hotspot (the original just-in-time compiler of OpenJDK)
+should not be too hard.
+If that fails we can fall back on Shark
+(a portable alternative JIT which uses LLVM).
+
+Complexity of porting HotSpot: probably low.  The complex things should be
+arch- rather than OS-specific.  Not many Linux-specific interfaces used.
+Garbage collection/memory management, etc. and/or most of other Linux-specific
+interfaces are already dealt with for the zero build.
+
+The dynamic linker issue is as follows.
+An executable-specific search path can be provided in the ELF RPATH header.
+RPATH directories can include the special string `$ORIGIN`,
+which is to be expanded to the directory the executable was loaded from.
+OpenJDK's `java` command uses this feature to locate
+the right `libjli.so` at runtime.
+However,
+on Hurd this information is not available to the dynamic linker
+and as a consequence RPATH components which include `$ORIGIN`
+are silently discarded.
+
+This can be worked around by defining
+the `LD_ORIGIN_PATH` environment variable.
+(which have I used to build and test OpenJDK so far.)
+
+#### Plans
+
+I intend to fix the RPATH issue
+by building on [[pochu]]'s `file_exec_file_name()`
+[patches](http://lists.gnu.org/archive/html/bug-hurd/2010-08/msg00023.html).
+
+I have succeeded in building a Hotspot-enabled `libjvm.so`,
+although the current toolchain issues
+([[toolchain/ELFOSABI_GNU]]; 2011-07-03: fix committed in binutils)
+have so far prevented me from testing it.
+
+> It turns out the build fails later on in `hotspot/agent`
+> because Hurd lack a `libthread_db.so`.
+> Also, a Shark version builds, but the result does not work so far.
+>
+> In other news, Damien Raude-Morvan is
+> [working on a kFreeBSD version](http://lists.debian.org/debian-java/2011/06/msg00124.html),
+> so I intend to merge my current patches with his.
+>
+> --[[jkoenig]] 2011-06-29
+
+##### Upstream Submission
+
+On 2011-07-15, *gnu_andrew* talked to us in the #hurd channel (freenode IRC),
+who is a maintainer of IcedTea.  He's supportive of the porting approach, and
+is willing to review and integrate small patches for individual issues (rather
+than some huge patchset).  Send patches to <distro-pkg-dev@openjdk.java.net>.
+
+##### Open Items
+
+  * [!] [[tschwinge]] to have a look at [[pochu]]'s `file_exec_file_name()`
+    patches, whether it's generally the right idea.
+
+      * Assuming it is, continue with getting `$ORIGIN` working.
+
+  * `libthread_db.so` issue.  Likely, the Serviceability Agent is used by jdb
+    and the like only, so for now the goal should be to lose some functionality
+    by removing/avoiding this dependency.
+
+  * [[java-access-bridge]] (not critical; JVM appears to work without)
+
+  * They seem to have a rather heavy-weight process for such projects: confer
+    <http://mail.openjdk.java.net/pipermail/announce/2011-January/000092.html>,
+    for example.  Do we need this, too?
+
+    > Probably not.
+    > My current approach (and Damien's wrt. the kFreeBSD patches)
+    > is to add preprocessor directives in the Linux code
+    > to make it more portable.
+    > --[[jkoenig]] 2011-06-29
+
+  * Eclipse
+
+    OK for testing -- but I'd very much hope that it *just works* as soon as we
+    provide the required Java platform.  But it may perhaps have some
+    Linux-specifics (needlessly?) in its basement.  Is it available for Debian
+    GNU/kFreeBSD already?
+
+
+### Java bindings for Mach
+
+The code is at <http://github.com/jeremie-koenig/hurd-java>.
+
+[[tschwinge]]'s notes for building with...
+
+  * GCJ installed (due to the current Debian multilib confusion):
+
+        $ tmp1=/usr/lib/gcc/i486-gnu/4.6 tmp2=/usr/lib/i386-gnu/gcc/i486-gnu/4.6 LIBRARY_PATH=$tmp2 COMPILER_PATH=$tmp1:$tmp2 C_INCLUDE_PATH=$tmp1/include make
+
+  * OpenJDK installed (to have it find the shared library, and the jni.h header
+    file):
+
+        $ jdk=/usr/lib/jvm/java-7-openjdk LD_LIBRARY_PATH=$jdk/jre/lib/i386/jli C_INCLUDE_PATH=$jdk/include make
+
+Doxygen-generated documentation is available at
+<http://jk.fr.eu.org/hurd-java/doc/html/>; or run `make doc` yourself.
+
+
+#### Plans
+
+(just started.)
+
+
+##### Open Items
+
+  * [[tschwinge]] has to read about RMI and CORBA.
+
+  * MIG
+
+      * Hacking [[microkernel/mach/MIG]] shouldn't be too difficult.
+
+          * (Unless you want to make MIG's own code (that is, not the generated
+            code, but MIG itself) look a bit more nice, too.)  ;-)
+
+      * There are also alternatives to MIG.  If there is interest, the following
+        could be considered:
+
+          * FLICK ([[!GNU_Savannah_task 5723]]).  [[tschwinge]] has no idea yet if
+            there would be any benefits over MIG, like better modularity (for the
+            backends)?  If we feel like it, we could spend a little bit of time on
+            this.
+
+          * For [[microkernel/Viengoos]], Neal has written a RPC stub generator
+            entirely in C Preprocessor macros.  While this is obviously not
+            directly applicable, perhaps we can get some ideas from it.
+
+          * Anything else that would be worth having a look at?  (What are other
+            microkernels using?)
+
+  * `mach_msg`
+
+      * Seems like the right approach to [[tschwinge]], but he hasn't digested
+        all the pecularities yet.  Will definitely need more time.
+
+
+## Postponed
+
+Might get back to these as time/interest permits.
+
+
+### GCJ
+
+  * [[tschwinge]] has the feeling that Java in GCC (that is, GCJ) is mostly
+    dead?  (True?)
+
+  * Thus perhaps not too much effort should be spent with it.
+
+    If the POSIX threads signal semantics makes it going, then great, otherwise
+    we should get a feeling what else is missing.
+
+
+### Joe-E.
diff --git a/user/jkoenig/java/discussion.mdwn b/user/jkoenig/java/discussion.mdwn
new file mode 100644
index 00000000..f16d7678
--- /dev/null
+++ b/user/jkoenig/java/discussion.mdwn
@@ -0,0 +1,526 @@
+[[!meta copyright="Copyright © 2011 Free Software Foundation, Inc."]]
+
+[[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable
+id="license" text="Permission is granted to copy, distribute and/or modify this
+document under the terms of the GNU Free Documentation License, Version 1.2 or
+any later version published by the Free Software Foundation; with no Invariant
+Sections, no Front-Cover Texts, and no Back-Cover Texts.  A copy of the license
+is included in the section entitled [[GNU Free Documentation
+License|/fdl]]."]]"""]]
+
+[[!toc]]
+
+
+# General
+
+Some [[tschwinge]] comments regarding your proposal.  Which is very good, if I
+may say so again!  :-)
+
+Of course, everyone is invited to contribute here!
+
+I want to give the following methodology a try, instead of only having
+email/IRC discussions -- for the latter are again and again showing a tendency
+to be dumped and deposited into their respective archives, and be forgotten
+there.  Of course, email/IRC discussions have their usefulness too, so we're
+not going to replace them totally.  For example, for conducting discussions
+with a bunch of people (who may not even be following these pages here), email
+(or, as applicable, the even more interactive IRC) will still be the medium of
+choice.  (And then, the executive summary should be posted here, or
+incorporated into your proposal.)
+
+Also, if you disagree with this suggested procedure right away, or at some
+later point begin to feel that this thing doesn't work out, or simply takes too
+much time (I don't think so: writing emails takes time, too), just say so, and
+we can reconsider.
+
+Of course, as this wiki is a passive medium rather than an active one as IRC
+and email are, it is fine to send notices like: *I have updated the wiki page,
+please have a look*.
+
+One idea is that your proposal evolves alongside with the ongoing work, and
+represents (in more or less detail) what has been done and what will be done.
+Also, we can hopefully use parts of it for documentation purposes, or as
+recipes for similar work (enabling other programming languages on the Hurd, for
+example).
+
+For this, I suggest the following procedure: as applicable, you can either
+address any comments in here (for example, if they're wrong :-), or if they
+require further discussion; think: *email discussion*), or you can address them
+directly in your propoal and remove the comments from here at the same time
+(think: *bug fix*).
+
+Generally, you can assume that for things I didn't comment on (within some
+reasonable timeframe/upon asking me again) that I'm fine with them.  Otherwise,
+I might say: *I don't like this as is, but I'll need more time to think about
+it.*
+
+There is also a possibility that parts of your proposal will be split off; in
+cases where we think they're valuable to follow, but not at this time.  (As you
+know, your proposal is not really a trivial one, so it may just be too much for
+one person's summer.)  Such bits could be moved to [[open_issues]] pages,
+either new ones or existing ones, as applicable.
+
+
+# GSoC Site Discussion
+
+  * Discussion items from
+    <http://www.google-melange.com/gsoc/proposal/review/google/gsoc2011/jkoenig/1>
+    should be copied here:
+
+      * technical bits (obviously);
+
+      * also the *why do we want Java bindings* reasoning;
+
+      * CLISP findings should also be documented somewhere permanently.
+
+          * We should probaby open up a *languages for Hurd* section on the web
+            pages ([[!taglink open_issue_documentation]]).
+
+
+# IRC, freenode, #hurd, 2011-07-13
+
+[[!tag open_issue_documentation]]
+
+    <jkoenig> Yes, I guess so. Maybe start investigating mig because it may
+      have repercussions on what the best approach would be for some aspects of
+      the Mach bindings.
+    <tschwinge> I still think that making MIG emit Java code is not too
+      difficult, once you have the required Java infrastructure (like what
+      you're writing at the moment).
+    <tschwinge> On the other hand, if there's another approach that you'd like
+      to use, I'm not trying to force using MIG.
+    <braunr> i still have a problem understanding your approach
+    <braunr> at which level are your bindings located ?
+    <jkoenig> I expect mig it will be the easiest route, but of course possibly
+      it won't.
+    <tschwinge> jkoenig: Yeah, be give some high-level to low-level overview?
+    <jkoenig> ok, so
+    <jkoenig> at the very core, low-level, we have a very thin amount of JNI
+      code to access (proper) system calls.
+    <jkoenig> by "proper" I mean things like mach_task_self, mach_msg and
+      mach_reply_port, which are actually system calls rather than RPCs to the
+      kernel.
+    <braunr> right
+    <jkoenig> at this level, we manipulate port names as integers, and the
+      message buffers for mach_msg are raw ByteBuffers (from the java.nio
+      package)
+    <jkoenig> actually, so-called /direct/ ByteBuffers, which are backed by
+      memory allocated outside of the Java heap, rather than as a byte[] array
+    <jkoenig> we can retreive the pointer from the JNI code and use the buffer
+      directly.
+    <jkoenig> (so, good for performance and it's also portable.)
+    <braunr> ok
+    <braunr> i'm more interested in the higher level bindings :)
+    <jkoenig> ok so, higher up.
+    <jkoenig> design goal from my proposal: "the memory safety of Java should
+      be maintained and extended to Mach primitives such as port names and
+      out-of-line memory regions"
+    <jkoenig> so integer port names are not "safe" in the sense that they can
+      be forged and misused in all kinds of way
+    <jkoenig> which is why I have a layer of Java code whose job is to wrap
+      this kind of low-level Mach stuff into safe abstractions
+    <jkoenig> and ideally the user should only use these safe abstractions.
+    <tschwinge> (Not to restrict the programmer, but to help him write correct
+      code.)
+    <jkoenig> right.
+    <braunr> so you can't use mach RPCs directly
+    <jkoenig> tschwinge, also to actually restrict them, in a Joe-E /
+      object-capability context, but that's not the primary concern right now
+      ;-)
+    <braunr> or you force your wrappers to have these abstractions as input
+    <jkoenig> braunr, well, actually at this level you still have Mach RPC
+    <jkoenig> but for instance, port names are encapsulated into "MachPort"
+      objects which ensure they are handled correcly
+    <tschwinge> As I understand it, you use these abstractions to prepare a
+      usual mach_msg message, and then invoke mach_msg.
+    <braunr> ok
+    <jkoenig> and message buffers are wrapped into "MachMsg" objects which both
+      help you write the messages into the ByteBuffer and prevent you from
+      doing funky stuff
+    <jkoenig> and ensure the ports which you send/receive/pseudo-receive after
+      an error/... are deallocated as required, etc.
+    <braunr> what's the interface to use IPC ?
+    <tschwinge> Is MIG doing that, too, I think?  (And antrik once found some
+      error there, which is still to be reviewed...)
+    <jkoenig> braunr, so basically as a user you would be free to use either
+      one of these layers, or to use MIG-generated classes which would
+      construct and exchange messages for you using the second (safe) layer.
+    <braunr> ok, let's just finish with the low level layer before going
+      further please
+    <jkoenig> tschwinge, MIG does some type checking on the received message
+      and saves you the trouble of constructing/parsing them yourself, but I'm
+      not sure about how mach_msg errors are handled
+    <braunr> what are the main methods of MachMsg for example ?
+    <jkoenig> braunr, you may want to have a look at
+      http://jk.fr.eu.org/hurd-java/doc/html/classorg_1_1gnu_1_1mach_1_1MachMsg.html
+    <braunr> right, sorry
+    <braunr> grabbed the code at work and forgot here
+    <jkoenig> and also
+      https://github.com/jeremie-koenig/hurd-java/blob/master/HelloMach.java
+      which uses it
+    <jkoenig> but roughly, you'd use setRemotePort, setLocalPort, setId to
+      write your message's header
+    <jkoenig> then use one of the putFoo() methods to add data items to the
+      message
+    <braunr> ok, the mapping with the low level C interface is very clear
+    <braunr> that's good for me
+    <jkoenig> the putFoo() methods would write the appropriate type
+      descriptors, then the actual data.
+    <braunr> we can go on with the MiG part if you want :)
+    <jkoenig> right,
+    <jkoenig> so here you may want to look at the UML class diagram from
+      http://www.bddebian.com/~hurd-web/user/jkoenig/java/proposal/
+    <jkoenig> so in the C case, mig generates 3 files
+    <jkoenig> a header file which has the prototypes of the mig-generated
+      stubs,
+    <jkoenig> a *User.c which has their actual implementation
+    <jkoenig> and a *Server.c which handles demultiplexing the incoming
+      messages and helps with implementing servers.
+    <jkoenig> so we would do something along these lines, more or less:
+    <jkoenig> mig would generate the code for a Java interface in lieu of the
+      *.h file.
+    <jkoenig> a generated FooUser class would implement this interface by doing
+      RPC
+    <jkoenig> (so basically you would pass a MachPort object to the
+      constructor, and then you could use the resulting object to do RPC with
+      whatever is on the other end)
+    <jkoenig> and the generated FooServer class would do the opposite,
+    <braunr> ok
+    <braunr> issues with threads ?
+    <jkoenig> you would pass an object implementing the Foo interface to the
+      constructor,
+    <braunr> i'm guessing the demux part may have to create threads, right ?
+    <jkoenig> and the resulting object would handle messages by using the
+      object you passed.
+    <jkoenig> braunr, right, so that would be more a libports kind of code,
+    <braunr> the libports-like library, i see
+    <jkoenig> to which you could pass Server objects (for instance the
+      FooServer above), and it would handle incoming messages.
+    <braunr> how is message content mapped to a java interface ?
+    <jkoenig> this would be determined from the .defs files and MIG would
+      generate the appropriate code, hopefully.
+    <braunr> so the demux part would handle rpc integer identifiers ?
+    <jkoenig> right.
+    <braunr> but hm
+    <jkoenig> also mapping .defs files to Java interfaces might prove to be
+      tricky. data types conversion and all
+    <antrik> tschwinge: my mamory is rather hazy. IIRC the issue was that the
+      MIG-generated stubs deallocate out-of-line port arrays after the
+      implementation returns, before returning to the dispatcher
+    <braunr> i'll just overlook this specific implementation detail
+    <jkoenig> but we could use some annotation-based system if we need to
+      provide more information to generate the java code.
+    <antrik> but the Hurd (or rather glibc) RPC handling also automatically
+      deallocates everything if an error occurs
+    <antrik> so I changed the MIG code to deallocate only when no error occurs
+    <braunr> jkoenig: ok, we'll talk about that when there is more progress and
+      you have a better view of the problem
+    <antrik> at that time I was pretty sure that this is a correctly working
+      solution, but it always seemed questionable conceptually... however, I
+      wasn't able to come up with a better one, and nobody else commented on it
+    <braunr> antrik: shouldn't the hurd be changed not to deallocate something
+      it didn't allocate in the first place ?
+    <antrik> braunr: no, the server has to deallocate stuff before returning to
+      the client. the request message is destroyed before returning the reply.
+    <tschwinge> jkoenig, braunr: That's what I had in mind where MIG might be a
+      bit awkward.  Then we can indeed either add annotations to the .defs
+      files, or reproduce them in some other format.  That's some work, but
+      it's mostly a one-time work.
+    <tschwinge> After all, the RPC interface is a binary one, and there may be
+      more than one API for creating these messages, etc.
+    <antrik> jkoenig: actually, at least in the Hurd, server-side and
+      client-side headers are separate -- so MIG actually creates four files
+    <jkoenig> tschwinge, wrt to annotations I was more thinking about Java
+      ones, such as: @MIGDefsFile("mach/task.defs") @MIGCType("task_t") public
+      interface Task { }
+    <jkoenig> antrik, oh, ok, it makes sense.
+    <braunr> jkoenig: anything else ?
+    <jkoenig> braunr, nothing that I can think of
+    <braunr> ok
+    <antrik> tschwinge: I think it would be a *very* bad idea to introduce
+      redundancy regarding RPC definitions
+    <braunr> thanks for the tour :)
+    <antrik> (the _request.defs/_reply.defs mess is bad enough...)
+    <jkoenig> did I speak about the "Unsafe" pseudo-exception? that's
+      interesting :-)
+    <tschwinge> jkoenig: Also, virtual memory abstractions?
+    <braunr> jkoenig: you didn't
+    <tschwinge> antrik: Well, then we could create some other super-format.
+      But that's just a detail IMO.
+    <jkoenig> ok, so wrt virtual memory, a page we received can be wrapped with
+      some JNI help into a (direct) ByteBuffer object.
+    <jkoenig> deallocating sent pages will be tricky, though.
+    <tschwinge> antrik: To put it this way: for me the .defs files are just one
+      way of expressing the RPC interfaces' contracts.  (At the same time, they
+      happen to be the actual reference for these, too.  But the specification
+      itself could just as well be a textual one.) 
+    <jkoenig> on approach I've been thinking about would be to "wrap" the
+      ByteBuffer object into an object which has the sole reference to it, so
+      that when it's deallocated the reference can be replaced with "null", and
+      further attempts to access the buffer would throw exceptions.
+    <braunr> sounds reasonable
+    <jkoenig> but that's still in flux in my head, we may end up needing our
+      own implementation of ByteBuffer-like objects.
+    <tschwinge> The problem being that there is no mechanism to ``revoke'' an
+      object once a reference to it has been shared.
+    <jkoenig> right.
+    <tschwinge> A wrapper is one possibility indeed.
+    <antrik> tschwinge: they are called interface *definitions* for a reason
+      :-)
+    <tschwinge> This is a very similar problem as with capabilities when there
+      is no revoke operation for these, too.
+    <tschwinge> antrik: Yes, because they define MIG's input.  :-P
+    <tschwinge> Isn't that what is called a membrane in the capability world?
+    <antrik> I do not say that we have to consider the format of the .defs to
+      be set in stone; but I do insist on using a canonical machine-parsable
+      source for all language bindings
+    <tschwinge> attenuation
+    <jkoenig> tschwinge, you mean the revokable proxy contruct ? (It's the same
+      principle indeed)
+    <tschwinge>     A common design pattern in object-capability systems: given
+      one reference of an object, create another reference for a proxy object
+      with certain security restrictions, such as only permitting read-only
+      access or allowing revocation. The proxy object performs security checks
+      on messages that it receives and passes on any that are allowed. Deep
+      attenuation refers to the case where the same attenuation is applied
+      transitively to any
+    <tschwinge>     objects obtained via the original attenuated object,
+      typically by use of a "membrane".
+    <tschwinge> http://en.wikipedia.org/wiki/Object-capability_model
+    <tschwinge> Yes.
+    <tschwinge> Good.  I understood something.  ;-)
+    <tschwinge> antrik: OKAY!  :-P
+    <tschwinge> jkoenig: And hopefully the JVM will optimize away all the
+      additional indirection...  :-D
+    <tschwinge> jkoenig: Is there anything more to say about the VM layer?
+    <jkoenig> tschwinge, "hopefully", yes :-)
+    <tschwinge> Like, the data that I'm sharing -- is it untyped, isn't it?
+    <jkoenig> tschwinge, you mean that within the received/sent pages ?
+    <tschwinge> Yes.
+    <tschwinge> But that'S how it is, indeed.
+    <jkoenig> well actually the type descriptor should indicate what they
+      contain.
+    <tschwinge> I cannot trust anything I receive from externally.
+    <jkoenig> it's most often used for MACH_MSG_TYPE_CHAR items I guess, and it
+      will be type checked when retreive
+    <tschwinge> Yeah, and that then just *is* arbitrary data, like a block read
+      from a disk file.
+    <jkoenig> you would have something like: ByteBuffer
+      MachMsg.getBuffer(MachMsg.Type expected), and MachMsg would check the
+      type descriptor against that which you specified
+    <tschwinge> Or a packet transmitted over the network.
+    <tschwinge> OK, yes.
+    <antrik> jkoenig: in theory ints should be used quite often too. the whole
+      purpose of the type descriptors is to allow byte order swapping when
+      messages are passed between hosts with different architecture...
+    <jkoenig> tschwinge, right, except for out-of-line port arrays, which need
+      to be handled differently obviously.
+    <antrik> (which is totally irrelevat for our purposes -- especially since
+      the actual network IPC code doesn't exist anymore ;-) )
+    <jkoenig> antrik, oh, interesting
+    <tschwinge> Yes, that was one original idea.
+    <jkoenig> actually my litmus test for what the bindings should be, is you
+      should be able to implement such a proxy in Java :-)
+    <tschwinge> antrik: And hey, you now have processors that can switch
+      between different modes during runtime...  :-)
+    <jkoenig> (although arguably that's a little bit ambitious)
+    <braunr> tschwinge: there should be bits in page tables to indicate the
+      endianness to use on a page .. :)
+    <tschwinge> Hehe!
+    <tschwinge> jkoenig: Don't worry -- you're already known for ambitious
+      projects.  One more can't hurt.
+    <jkoenig> Also, actually the word size is not something that I've been able
+      to abstract so far, so I'll be hardcoding little-endian 32 bits for now.
+    <braunr> why is that ?
+    <antrik> some of the Hurd RPC break the idea anyways BTW
+    <jkoenig> the org.vmmagic package (from Jikes RVM and JNode) could help
+      with that, but GCJ does not support it unfortunately (not sure about
+      OpenJDK)
+    <jkoenig> braunr, Java does not allow us to define new unboxed types
+    <braunr> jkoenig: does it have its own definition of the word size ?
+    <jkoenig> braunr, nope.
+    <jkoenig> (although, maybe, and also we could use JNI to query it)
+    <braunr> even if virtual, i'd expect a machine to have such a defnition
+    <jkoenig> braunr, maybe it has, but basically in Java nothing depends on
+      the word size
+    <jkoenig> 'int' is 32 bits, 'long' is 64 and that's it.
+    <braunr> oh right, i remember most types are fixed size, right ?
+    <jkoenig> right.
+    <braunr> if not all
+    <jkoenig> now Jikes RVM's "org.vmmagic" provides an interface to defined
+      new unboxed types which can depend on the actual word size, but Jikes RVM
+      is its own JVM so obviously they can use and provide whatever extensions
+      they need :-)
+    <jkoenig> (but maybe they've implemented them in OpenJDK for bootstrap
+      purposes, I'm not sure)
+    <tschwinge> I'm missing this detail: where does the word size come into
+      play here?
+    <jkoenig> anyway, I _could_ indiscriminately use 'long' for port names, and
+      sparkle the code with word size tests but that would be very clumsy
+    <braunr> jkoenig: port names are actually ints :/
+    <jkoenig> tschwinge, the actual format of the message header and type
+      descriptors, for instance.
+    <braunr> jkoenig: ok, got your point
+    <jkoenig> braunr, by 'long' I mean 64-bits integers (which they are on
+      64-bits machines I think?)
+    <braunr> :)
+    <braunr> jkoenig: port names are as large as the word size
+    <braunr> but in C at least, they're int, not long
+    <braunr> it doesn't change many things, but you get lots of warnings if you
+      try with a long :)
+    <tschwinge> What is the reason that port names are an
+      architecture-dependent word size's width, and not simply 32 bit?
+    <jkoenig> "4 billions of port names should be enough for everyone" :-)
+    <braunr> tschwinge: an optimization is to use them as pointers in the
+      kernel
+    <antrik> tschwinge: the machine's native word size is what it can process
+      most efficiently, and what should be used for most normal
+      operations... it makes sense to define stuff as int, except for network
+      communication
+    <tschwinge> jkoenig: Well, yeah, but if you want to communicate with a
+      peer, you have to agree on the maximum number anyway (not for port names,
+      though, which are local).
+    <braunr> antrik: int isn't the word size everywhere
+    <braunr> antrik: the most common type matching the word size is long, at
+      least on ILP32/LP64 data models
+    <antrik> braunr: that's just because some idiots assumed int would always
+      be 32 bits, and consequently when 64 architectures came up the compiler
+      guys chickened out ;-)
+    <braunr> without int, you wouldn't have a 32 bits type
+    <antrik> that's not true for all architectures and/or operating systems
+      though AFAIK
+    <braunr> or a 16 bits one
+    <braunr> antrik: windows guys got even more scared, so windows 64 is LLP64
+    <antrik> BTW, I haven't checked, but it's quite possible that 32 bit
+      numbers are actually preferable even on AMD64...
+    <tschwinge> jkoenig: So, back on track.  :-)
+    <tschwinge> jkoenig: You didn't find anything yet in Mach's VM interfaces
+      as well a MemoryObject, etc., that can't be used/implemented in the Java
+      world?
+    <braunr> antrik: they consume less memory, but don't have much effect on
+      performance
+    <jkoenig> tschwinge, once we have the basic system calls and the
+      corresponding abstractions in place, I don't think anything else
+      fundamentally problematic could possibly show up
+    <antrik> braunr: if you really *need* a type of a certain bit size, you
+      should use stdint types. so not having a 16 or 32 bit type in the
+      short/int/long canon is *not* an excuse
+    <tschwinge> jkoenig: That speaks for the Mach designers!
+    <braunr> antrik: right
+    <jkoenig> tschwinge, on trick is that for instance, mach_task_self would
+      still be unsafe even if it returned a nicely wrapped Task object, because
+      you could still wreck your own address space and threads with it. So we
+      would need the "attenuation" pattern mentionned above to provide a safe
+      one.
+    <jkoenig> (which would disallow thinks such as the port/thread/vm calls)
+    <braunr> jkoenig: you mentioned the unsafe pseudo exception earlier
+    <jkoenig> braunr, right, so the issue is with distinguishing safe from
+      unsafe methods
+    <antrik> braunr: BTW, the Windows guys actually broke a lot of stuff by
+      fixing long at 32 bits -- this way long doesn't match size_t and pointer
+      types anymore, which was an assumption that was true for pretty much any
+      system so far...
+    <tschwinge> jkoenig: Yes.  (And again hope for the JVM to optim...)
+    <braunr> antrik: that's right :)
+    <braunr> antrik: that's LLP64
+    <braunr> antrik: long long and pointers
+    <jkoenig> braunr, so basically the idea is that unsafe methods are declared
+      as "throws Unsafe"
+    <jkoenig> the effect is that if you use such a method you must either
+      "throw Unsafe" yourself,
+    <jkoenig> or if you're building a safe abstraction on top of Unsafe
+      methods, you'll "catch" the "exception" in question to tell the compiler
+      that it's okay.
+    <jkoenig> it's more or less inspired from the "semantic regimes" idea from
+      the org.vmmagic paper which is referenced in my original proposal,
+    <jkoenig> only implementing by hijacking the exception checking machinery,
+      which has a behaviour similar to what we want.
+    <braunr> ok
+    <braunr> but hmm this seems pretty normal, what's the tricky part ? :)
+    <tschwinge> braunr: The idea is that the programmer explicitly has to
+      acknowledge if he'S using an unsafe interface.
+    <braunr> tschwinge: sounds pretty normal too
+    <jkoenig> braunr, the trick is that you would not usually declare
+      exceptions which are never actually thrown (and actually since the
+      compiler does not know it's never thrown, I need to work around it in a
+      few places)
+    <braunr> oh, ok
+    <braunr> jkoenig: that's interesting indeed
+    <jkoenig> braunr, the org.vmmagic paper provides an example which uses some
+      annotations called @UncheckedMemoryAccess and @AssertSafe to the same
+      effect (which is kind of cleaner), but it would be a headache to
+      implement without help from the compiler I think (as far as I can tell
+      the annotation processor would have to inspect the bytecode)
+    <braunr> but hm
+    <braunr> what's the true problem about this ?
+    <jkoenig> (the paper advocates "high-level low-level programming" and is a
+      very interesting read I think,
+      http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.151.5253&rep=rep1&type=pdf,
+      for what it's worth)
+    <braunr> what's wrong if you just declare your methods unsafe and don't
+      alter anything else ?
+    <tschwinge> Yes, I read it and it is interesting.  Unfortunately, it seems
+      I forgot most of it again...
+    <jkoenig> braunr, declare? alter?
+    <jkoenig> you mean just tag them with an annotation?
+    <braunr> just stating a method "throws Unsafe"
+    <jkoenig> braunr, well some compiler will output a warning because they can
+      tell there's no way the method is going to throw such an exception.
+    <jkoenig> and then some other compiler will complain that my
+      @SuppressWarnings("unused") does not serve any purpose to them :-)
+    <jkoenig> also, when initializing final fields, I need to work around the
+      fact that the compiler thinks "Unsafe" might be thrown.
+    <jkoenig> see for instance MachPort.DEAD
+    <braunr> jkoenig: ok
+    <jkoenig> braunr, but I'm more than willing to accept this in exchange for
+      a clear, compiler-enforced materialization of the border between safe an
+      unsafe code.
+    <jkoenig> actually another question I have is the amount of static typing I
+      should add to the safe version, for instance should I subclass MachPort
+      into MachSendRight, MachReceiveRight and so on. I don't want to depart
+      from the C inteface too much but it could be useful.
+    <braunr> jkoenig: can't answer that :)
+    <braunr> jkoenig: keep them in mind for later i think
+    <tschwinge> jkoenig: What's the safety concern w.r.t. having MachPort (not)
+      final?
+    <jkoenig> tschwinge, actually I'm partly wrong in that we only need name()
+      and a couple other methods to be final
+    <tschwinge> jkoenig: That's what I was thinking.  :-)
+    <tschwinge> I though I'm missing something here.
+    <jkoenig> tschwinge, the idea is that the user (ie., the adversary :-)
+      could extend MachPort and inject their own fake port name into messages
+    <jkoenig> by overriding name() or clear()
+    <tschwinge> Yeah, but if these are final, that's not possible.
+    <jkoenig> right.
+    <tschwinge> And that *should* be enough, I think.
+    <tschwinge> Unless I'm missing something.
+    <jkoenig> I don't think so. Also I hope it is, because as mentionned above
+      there might be some value in subclassing MachPort.
+    <tschwinge> Yep.
+    <jkoenig> incidentally, declaring the class or the method final will allow
+      the JVM to inline them I think.
+    <tschwinge> It will help the JVM, yes.  It can also figure that out without
+      final, though.  (And may have to de-optimize the code again in case there
+      are additional classes loaded during run-time.)
+    <tschwinge> jkoenig: The reference counting in MachPort.  I think I'm
+      beginning to understand this.
+    <jkoenig> oh ok
+    <jkoenig> tschwinge, yes the javadoc is maybe a bit obscure so far.
+    <jkoenig> but basically you don't want the port name you acquire to become
+      invalid before you're done using it.
+    <tschwinge> But how is this different from the C world?
+    <jkoenig> here my goal is to provide some guarantees if you use only safe
+      methods
+    <jkoenig> like, you can't forge a port name and things like that
+    <jkoenig> so basically it should never be possible to include an invalid
+      port name in a message if you use only safe methods.
+    <tschwinge> Ah, I see!
+    <tschwinge> Now that does make sense.
+    <jkoenig> but the mechanism in itself is similar to the Hurd port cells and
+      user_link structures
+    <tschwinge> It's again ``only'' helping the programmer.
+    <jkoenig> right, no object-capability ulterior motives :-)
+    <jkoenig> another assumption which the javadoc does not state yet it that
+      basically there should be exactly one MachPort object for each mach-level
+      port name reference (in the sense of mach_port_mod_refs)
+    <tschwinge> Yes, I figured out that bit.
diff --git a/user/jkoenig/java/java-access-bridge.mdwn b/user/jkoenig/java/java-access-bridge.mdwn
new file mode 100644
index 00000000..6f860709
--- /dev/null
+++ b/user/jkoenig/java/java-access-bridge.mdwn
@@ -0,0 +1,78 @@
+[[!meta copyright="Copyright © 2011 Free Software Foundation, Inc."]]
+
+[[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable
+id="license" text="Permission is granted to copy, distribute and/or modify this
+document under the terms of the GNU Free Documentation License, Version 1.2 or
+any later version published by the Free Software Foundation; with no Invariant
+Sections, no Front-Cover Texts, and no Back-Cover Texts.  A copy of the license
+is included in the section entitled [[GNU Free Documentation
+License|/fdl]]."]]"""]]
+
+[[!tag open_issue_porting]]
+
+Debian's *openjdk-7-jre* package depends on *libaccess-bridge-java-jni* (source
+package: *java-access-bridge*).
+
+The latter one has *openjdk-6-jdk* as a build dependency, but that can be
+hacked around:
+
+    # ln -s java-7-openjdk /usr/lib/jvm/java-6-openjdk
+
+Trying to build it:
+
+    $ LD_LIBRARY_PATH=/usr/lib/jvm/java-7-openjdk/jre/lib/i386/jli dpkg-buildpackage -b -uc -d
+    [...]
+    make[3]: Entering directory `/media/erich/home/thomas/tmp/libaccess-bridge-java-jni/java-access-bridge-1.26.2/idlgen'
+    /usr/lib/jvm/java-6-openjdk/bin/idlj \
+                    -pkgPrefix Bonobo org.GNOME \
+                    -pkgPrefix Accessibility org.GNOME \
+                    -emitAll -i /usr/share/idl/bonobo-activation-2.0 -i /usr/share/idl/at-spi-1.0 -i /usr/share/idl/bonobo-2.0 \
+                    -fallTie /usr/share/idl/at-spi-1.0/Accessibility.idl
+    /usr/share/idl/at-spi-1.0/Accessibility_Collection.idl (line 66):  WARNING: Identifier `object' collides with a keyword; use an escaped identifier to ensure future compatibility.
+            boolean isAncestorOf (in Accessible object);
+                                         ^
+    /usr/share/idl/at-spi-1.0/Accessibility_Component.idl (line 83):  WARNING: Identifier `Component' collides with a keyword; use an escaped identifier to ensure future compatibility.
+      interface Component : Bonobo::Unknown {
+                ^
+    Exception in thread "main" java.lang.AssertionError: Platform not recognized
+            at sun.nio.fs.DefaultFileSystemProvider.create(DefaultFileSystemProvider.java:71)
+            at java.nio.file.FileSystems$DefaultFileSystemHolder.getDefaultProvider(FileSystems.java:108)
+            at java.nio.file.FileSystems$DefaultFileSystemHolder.access$000(FileSystems.java:89)
+            at java.nio.file.FileSystems$DefaultFileSystemHolder$1.run(FileSystems.java:98)
+            at java.nio.file.FileSystems$DefaultFileSystemHolder$1.run(FileSystems.java:96)
+            at java.security.AccessController.doPrivileged(Native Method)
+            at java.nio.file.FileSystems$DefaultFileSystemHolder.defaultFileSystem(FileSystems.java:95)
+            at java.nio.file.FileSystems$DefaultFileSystemHolder.<clinit>(FileSystems.java:90)
+            at java.nio.file.FileSystems.getDefault(FileSystems.java:176)
+            at sun.util.calendar.ZoneInfoFile$1.run(ZoneInfoFile.java:489)
+            at sun.util.calendar.ZoneInfoFile$1.run(ZoneInfoFile.java:480)
+            at java.security.AccessController.doPrivileged(Native Method)
+            at sun.util.calendar.ZoneInfoFile.<clinit>(ZoneInfoFile.java:479)
+            at sun.util.calendar.ZoneInfo.getTimeZone(ZoneInfo.java:658)
+            at java.util.TimeZone.getTimeZone(TimeZone.java:559)
+            at java.util.TimeZone.setDefaultZone(TimeZone.java:656)
+            at java.util.TimeZone.getDefaultRef(TimeZone.java:623)
+            at java.util.TimeZone.getDefault(TimeZone.java:610)
+            at java.text.SimpleDateFormat.initializeCalendar(SimpleDateFormat.java:682)
+            at java.text.SimpleDateFormat.<init>(SimpleDateFormat.java:619)
+            at java.text.DateFormat.get(DateFormat.java:772)
+            at java.text.DateFormat.getDateTimeInstance(DateFormat.java:547)
+            at com.sun.tools.corba.se.idl.toJavaPortable.Util.writeProlog(Util.java:1139)
+            at com.sun.tools.corba.se.idl.toJavaPortable.Skeleton.writeHeading(Skeleton.java:145)
+            at com.sun.tools.corba.se.idl.toJavaPortable.Skeleton.generate(Skeleton.java:102)
+            at com.sun.tools.corba.se.idl.toJavaPortable.InterfaceGen.generateSkeleton(InterfaceGen.java:159)
+            at com.sun.tools.corba.se.idl.toJavaPortable.InterfaceGen.generate(InterfaceGen.java:108)
+            at com.sun.tools.corba.se.idl.InterfaceEntry.generate(InterfaceEntry.java:110)
+            at com.sun.tools.corba.se.idl.toJavaPortable.ModuleGen.generate(ModuleGen.java:75)
+            at com.sun.tools.corba.se.idl.ModuleEntry.generate(ModuleEntry.java:83)
+            at com.sun.tools.corba.se.idl.Compile.generate(Compile.java:324)
+            at com.sun.tools.corba.se.idl.toJavaPortable.Compile.start(Compile.java:169)
+            at com.sun.tools.corba.se.idl.toJavaPortable.Compile.main(Compile.java:146)
+    make[3]: *** [org/GNOME/Accessibility/Accessible.java] Error 1
+    make[3]: Leaving directory `/media/erich/home/thomas/tmp/libaccess-bridge-java-jni/java-access-bridge-1.26.2/idlgen'
+    make[2]: *** [all-recursive] Error 1
+    make[2]: Leaving directory `/media/erich/home/thomas/tmp/libaccess-bridge-java-jni/java-access-bridge-1.26.2/idlgen'
+    make[1]: *** [all-recursive] Error 1
+    make[1]: Leaving directory `/media/erich/home/thomas/tmp/libaccess-bridge-java-jni/java-access-bridge-1.26.2'
+    make: *** [debian/stamp-makefile-build] Error 2
+    dpkg-buildpackage: error: debian/rules build gave error exit status 2
diff --git a/user/jkoenig/java/proposal.mdwn b/user/jkoenig/java/proposal.mdwn
new file mode 100644
index 00000000..4052f455
--- /dev/null
+++ b/user/jkoenig/java/proposal.mdwn
@@ -0,0 +1,628 @@
+
+# Java for Hurd (and vice versa)
+
+Contact information:
+
+  * Full name: Jérémie Koenig
+  * Email: jk@jk.fr.eu.org
+  * IRC: jkoenig on Freenode and OFTC
+
+## Introductions
+
+I am a first year M.Sc. student
+in Computer Science at University of Strasbourg (France).
+My interests include capability-based security,
+programming languages and formal methods
+(in particular, object-capability languages and proof-carrying code).
+
+### Proposal summary
+
+This project would consist in improving Java support on Hurd.
+The first part would consist in
+fixing bugs and porting Java-related packages.
+The second part would consist in
+creating low-level Java bindings for the Hurd interfaces,
+as well as libraries to make translator development easier.
+
+### Previous involvement
+
+I started contributing to Hurd last summer,
+during which I participated to Google Summer of Code
+as a student for the Debian project.
+I worked on porting Debian-Installer to Hurd.
+This project was mostly a success,
+although we still have to use a special mirror for installation
+with a few modified packages
+and tweaked priorities
+to work around some uninstallable packages
+with Priority: standard.
+
+Shortly afterwards,
+I rewrote the procfs translator
+to fix some issues with memory leaks,
+make it more reliable,
+and improve compatibility with Linux-based tools
+such as `procps` or `htop`.
+
+Although I have not had as much time
+as I would have liked to dedicate to the Hurd
+since that time,
+I have continued to maintain the mirror in question,
+and I have started to work
+on implementing POSIX threads signal semantics in glibc.
+
+### Project-related skills and interests
+
+I have used Java mostly for university assignments.
+This includes non-trivial projects
+using threads and distributed programming frameworks
+such as Java RMI or CORBA.
+I have also used it to experiment with
+Google App Engine
+(web applications)
+and Google Web Toolkit
+(a compiler from Java to Javascript which helps with AJAX code),
+and I have some limited experience with JNI
+(the Java Native Interface, to link Java with C code).
+
+My knowledge of the Hurd and Debian GNU/Hurd is reasonable,
+as the Debian-Installer and procfs projects
+gave me the opportunity to fiddle with many parts of the system.
+
+Initially,
+I started working on this project because I wanted to use
+[Joe-E](http://code.google.com/p/joe-e/)
+(a subset of Java)
+to investigate the potential
+[[applications of object-capability languages|objcap]]
+in a Hurd context.
+I also believe that improving Java support on Hurd
+would be an important milestone.
+
+### Organisational matters
+
+I am subscribed to bug-hurd@g.o and
+I do have a permanent internet connexion.
+
+I would be able to attend the regular IRC meetings,
+and otherwise communicate with my mentor
+through any means they would prefer
+(though I expect email and IRC would be the most practical).
+Since I'm already familiar with the Hurd,
+I don't expect I would require too much time from them.
+
+My exams end on May 20 so I would be able to start coding
+right at the beginning of the GSoC period.
+Next year's term would probably begin around September 15,
+so that would not be an issue either.
+I expect I would work around 40 hours per week,
+and my waking hours would be flexible.
+
+I don't have any other plans for the summer
+and would not make any if my project were to be accepted.
+
+Full disclosure:
+I also submitted a proposal to the Jikes RVM project
+(which is a research-oriented Java Virtual Machine,
+itself written in Java)
+for implementing a new garbage collector into the MMTk subsystem.
+
+## Improve Java support
+
+### Justification
+
+Java is a popular language and platform used by many desktop and web
+applications (mostly on the server side). As a consequence, competitive Java
+support is important for any general-purpose operating system.
+Better Java support would also be a prerequisite
+for the second part of my proposal.
+
+### Current situation
+
+Java is currently supported on Hurd with the GNU Java suite:
+
+   * [GCJ](http://gcc.gnu.org/java/),
+     the GNU Compiler for Java, is part of GCC and can compile Java
+     source code to Java bytecode, and both source code and bytecode to
+     native code;
+   * libgcj is the implementation of the Java runtime which GCJ uses.
+     It is based on [GNU Classpath](http://www.gnu.org/software/classpath/).
+     It includes a bytecode interpreter which enables
+     Java applications compiled to native code to dynamically load and execute
+     Java bytecode from class files.
+   * The gij command is a wrapper around the above-mentioned virtual machine
+     functionality of libgcj and can be used as a replacement for the java
+     command.
+
+However, GCJ does not work flawlessly on Hurd.r
+For instance, some parts of libgcj relies on
+the POSIX threads signal semantics, which are not yet implemented.
+In particular, this makes ant hang waiting for child processes,
+which makes some packages fail to build on Hurd
+(“ant” is the “make” of the Java world).
+
+### Tasks
+
+   * **Finish implementing POSIX thread semantics** in glibc (high priority).
+     According to POSIX, signal dispositions should be global to a process,
+     while signal blocking masks should be thread-specific. Signals sent to the
+     process as a whole are to be delivered to any thread which does not block
+     them. By contrast, Hurd has per-thread signal dispositions and signals
+     sent to a process are delivered to the main thread only. I have been
+     working on refactoring the glibc signal code and implementing the POSIX
+     semantics as a per-thread option. However, due to lack of time I have not
+     yet been able to test and debug my code properly. Finishing this work
+     would be my first task.
+   * **Fix further problems with GCJ on Hurd** (high priority). While I’m not
+     aware of any other problems with GCJ at the moment, I suspect some might
+     turn up as I progress with the other tasks. Fixing these problems would
+     also be a high-priority task.
+   * **Port OpenJDK 6** (medium priority). While GCJ is fine, it is not yet
+     100% complete. It is also slower than OpenJDK on architectures where a
+     just-in-time compiler is available. Porting OpenJDK would therefore
+     improve Java support on Hurd in scope and quality. Besides, it would also
+     be a good way to test GCJ, which is used for bootstrapping by the Debian
+     OpenJDK packages. Also note that OpenJDK 6 is now the default Java
+     Runtime Environment on all released Linux-based Debian architectures;
+     bringing Hurd in line with this would probably be a good thing.
+   * **Port Eclipse and other Java applications** (low priority). Eclipse is a
+     popular, state-of-the-art IDE and tool suite used for Java and other
+     languages. It is a dependency of the Joe-E verifier (see part 3 of this
+     proposal). Porting Eclipse would be a good opportunity to test GCJ and
+     OpenJDK.
+
+### Deliverables
+
+  * The glibc pthreads patch and any other fixes on the Hurd side
+    would be submitted upstream
+  * Patches against Debian source packages
+    required to make them build on Hurd would be submitted
+    to the [Debian bug tracking system](http://bugs.debian.org/).
+
+
+## Create Java bindings for the Hurd interfaces
+
+### Justification
+
+Java is used for many applications and often taught to
+introduce object-oriented programming. The fact that Java is a
+garbage-collected language makes it easier to use, especially for the less
+experienced programmers. Besides, its object-oriented nature is a
+natural fit for the capability-based design of Hurd.
+The JVM is also used as a target for many other languages,
+all of which would benefit from the access provided by these bindings.
+
+Advantages over other garbage-collected, object-oriented languages include
+performance, type safety and the possibility to compile a Java translator to
+native code and
+[link it statically](http://gcc.gnu.org/wiki/Statically_linking_libgcj)
+using GCJ, should anyone want to use a
+translator written in Java for booting.
+Note that Java is
+[being](http://www.linuxjournal.com/article/8757)
+[used](http://oss.readytalk.com/avian/)
+in this manner for embedded development.
+Since GCJ can take bytecode as its input,
+this expect this possibility would apply to any JVM-based language.
+
+Java bindings would lower the bar for newcomers
+to begin experimenting with what makes Hurd unique
+without being faced right away with the complexity of
+low-level systems programming.
+
+### Tasks summary
+
+  * Implement Java bindings for Mach
+  * Implement a libports-like library for Java
+  * Modify MIG to output Java code
+  * Implement libfoofs-like Java libraries
+
+### Design principles
+
+The principles I would use to guide the design
+of these Java bindings would be the following ones:
+
+  * The system should be hooked into at a low level,
+    to ensure that Java is a "first class citizen"
+    as far as the access to the Hurd's interfaces is concerned.
+  * At the same time, the memory safety of Java should be maintained
+    and extended to Mach primitives such as port names and
+    out-of-line memory regions.
+  * Higher-level interfaces should be provided as well
+    in order to make translator development
+    as easy as possible.
+  * A minimum amount of JNI code (ie. C code) should be used.
+    Most of the system should be built using Java itself
+    on top of a few low-level primitives.
+  * Hurd objects would map to Java objects.
+  * Using the same interfaces,
+    objects corresponding to local ports would be accessed directly,
+    and remote objects would be accessed over IPC.
+
+One approach used previously to interface programming languages with the Hurd
+has been to create bindings for helper libraries such as libtrivfs. Instead,
+for Java I would like to take a lower-level approach by providing access to
+Mach primitives and extending MIG to generate Java code from the interface
+description files.
+
+This approach would be initially more involved, and would introduces several
+issues related to overcoming the "impedance mismatch" between Java and Mach.
+However, once an initial implementation is done it would be easier to maintain
+in the long run and we would be able to provide Java bindings for a large
+percentage of the Hurd’s interfaces.
+
+### Bindings for Mach system calls
+
+In this low-level approach, my intention is to enable Java code to use Mach
+system calls (in particular, mach_msg) more or less directly. This would
+ensure full access to the system from Java code, but it raises a number of
+issues:
+
+  * the Java code must be able to manipulate Mach-level entities, such as port
+    rights or page-aligned buffers mapped outside of the garbage-collected
+    heap (for out-of-line transfers);
+  * putting together IPC messages requires control of the low-level
+    representation of data.
+
+In order to address these concerns, classes would be encapsulating these
+low-level entities so that they can be referenced through normal, safe objects
+from standard Java code. Bindings for Mach system calls can then be provided
+in terms of these classes. Their implementation would use C code through the
+Java Native Interface (JNI).
+
+More specifically, this functionality would be provided by the `org.gnu.mach`
+package, which would contain at least the following classes:
+
+  * `MachPort` would encapsulate a `mach_port_t`. (Some of) its constructors
+    would act as an interface for the `mach_port_allocate()` system call.
+    `MachPort` objects would also be instantiated from other parts of the JNI
+    C code to represent port rights received through IPC. The `deallocate()`
+    method would call `mach_port_deallocate()` and replace the encapsulated
+    port name with `MACH_PORT_DEAD`. We would recommend that users call it
+    when a port is no longer used, but the finalizer would also deallocate the
+    port when the `MachPort` object is garbage collected.
+  * `Buffer` would represent a page-aligned buffer allocated outside of the
+    Java heap, to be transferred (or having been received) as out-of-line
+    memory. The JNI code would would provide methods to read and write data at
+    an arbitrary offset (but within bounds) and would use `vm_allocate()` and
+    `vm_deallocate()` in the same spirit as for `MachPort` objects.
+  * `Message` would allow Java code to put together Mach messages. The
+    constructor would allocate a `byte[]` member array of a given size.
+    Additional methods would be provided to fill in or query the information
+    in the message header and additional data items, including `MachPort` and
+    `Buffer` objects which would be translated to the corresponding port names
+    and out-of-line pointers.
+    A global map from port names to the corresponding `MachPort` object
+    would probably be needed to ensure that there is a one-to-one
+    correspondence.
+  * `Syscall` would provide static JNI methods for performing system calls not
+    covered by the above classes, such as `mach_msg()` or
+    `mach_thread_self()`.  These methods would accept or return `MachPort`,
+    `Buffer` and `Message` objects when appropriate. The associated C code
+    would access the contents of such objects directly in order to perform the
+    required unsafe operations, such as constructing `MachPort` and `Buffer`
+    objects directly from port names and C pointers.
+
+Note that careful consideration should be given to the interfaces of these
+classes to avoid “safety leaks” which would compromise the safety guarantees
+provided by Java. Potential problematic scenarios include the following
+examples:
+
+  * It must not be possible to write an integer at some position in a
+    `Message` object, and to read it back as a `MachPort` or `Buffer` object,
+    since this would allow unsafe access to arbitrary memory addresses and
+    mach port names.
+  * Providing the `mach_task_self()` system call would also provide access to
+    arbitrary addresses and ports by using the `vm_*` family of RPC operations
+    with the returned `MachPort` object. This means that the relevant task
+    operations should be provided by the `Syscall` class instead.
+
+Finally, access should be provided to the initial ports and file descriptors
+in `_hurd_ports` and provided by the `getdport()` function,
+for instance through static methods such as
+`getCRDir()`, `getCWDir()`, `getProc()`, ... in a dedicated class such as
+`org.gnu.hurd.InitPorts`.
+
+A realistic example of code based on such interfaces would be:
+
+    import org.gnu.mach.MsgType;
+    import org.gnu.mach.MachPort;
+    import org.gnu.mach.Buffer;
+    import org.gnu.mach.Message;
+    import org.gnu.mach.Syscall;
+    import org.gnu.hurd.InitPorts;
+
+    public class Hello
+    {   
+       public static main(String argv[])
+           /* Parent class for all Mach-related exceptions */
+           throws org.gnu.mach.MachException
+       {   
+           /* Allocate a reply port */
+           MachPort reply = new MachPort();
+
+           /* Allocate an out-of-line buffer */
+           Buffer data = new Buffer(MsgType.CHAR, 13);
+           data.writeString(0, "Hello, World!");
+
+           /* Craft an io_write message */
+           Message msg = new Message(1024);
+           msg.setRemotePort(InitPorts.getdport(1));
+           msg.setLocalPort(reply, Message.Type.MAKE_SEND_ONCE);
+           msg.setId(21000);
+           msg.addBuffer(data);
+
+           /* Make the call, MACH_MSG_SEND | MACH_MSG_RECEIVE */
+           Syscall.machMsg(msg, true, true, reply);
+
+           /* Extract the returned value */
+           msg.assertId(21100);
+           int retCode = msg.readInt(0);
+           int amount = msg.readInt(1);
+       }
+    }
+
+Should this paradigm prove insufficient,
+more ideas could be borrowed from the
+[`org.vmmagic`](http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.151.5253&rep=rep1&type=pdf)
+package used by [Jikes RVM](http://jikesrvm.org/),
+a research Java virtual machine itself written in Java.
+
+### Generating Java stubs with MIG
+
+Once the basic machinery is in place to interface with Mach, Java programs
+have more or less equal access to the system functionality without resorting
+to more JNI code. However, as illustrated above, this access is far from
+convenient.
+
+As a solution I would modify MIG to add the option to output Java code. MIG
+would emit a Java interface, a client class able to implement the interface
+given a Mach port send right, an a server class which would be able to handle
+incoming messages. The class diagram below, although it is by no means
+complete or exempt of any problem, illustrates the general idea:
+
+[[gsoc2011_classes.png]]
+
+This structure is somewhat reminiscent of
+[Java RMI](http://en.wikipedia.org/wiki/Java_remote_method_invocation)
+or similar systems,
+which aim to provide more or less transparent access to remote objects.
+The exact way the Java code would be generated still needs to be determined,
+but basically:
+
+  * An interface, corresponding to the header files generated by MIG, would
+    enumerate the operations listed in a given .defs files. Method names would
+    be transformed to adhere to Java conventions (for instance,
+    `some_random_identifier` would become `someRandomIdentifier`).
+  * A user class, corresponding to the `*User.c` files,
+    would implement this interface by doing RPC over a given MachPort object.
+  * A server class, corresponding to `*Server.c`, would be able to handle
+    incoming messages using a user-provided implementation of the interface.
+    (Possibly, a skeleton class providing methods which would raise
+    `NotImplementedException`s would be provided as well.
+    Users would derive from this class and override the relevant methods.
+    This would allow them not to implement some operations,
+    and would avoid pre-existing code from breaking when new operations are
+    introduced.)
+
+In order to help with the implementation of servers, some kind of library
+would be needed to associate Mach receive rights with server objects and to
+handle incoming messages on dedicated threads, in the spirit of libports.
+This would probably require support for port sets at the level of the Mach
+primitives described in the previous section.
+
+When possible, operations involving the transmission of send rights
+of some kind would be expressed in terms of the MIG-generated interfaces
+instead of `MachPort` objects.
+Upon reception of a send right,
+a `FooUser` object would be created
+and associated with the corresponding `MachPort` object.
+If the received send right corresponds to a local port
+to which a server object has been associated,
+this object would be used instead.
+This way,
+subsequent operations on the received send right
+would be handled as direct method calls
+instead of going through RPC mechanisms.
+
+Some issues will still need to be solved regarding how MIG will convert
+interface description files to Java interfaces. For instance:
+
+  * `.defs` files are not explicitly associated with a type. For instance in
+    the example above, MIG would have to somehow infer that io_t corresponds
+    to `this` in the `Io` interface.
+  * More generally, a correspondence between MIG and Java types would have
+    to be determined. Ideally this would be automated and not hardcoded
+    too much.
+  * Initially, reply port parameters would be ignored. However they may be
+    needed for some applications.
+
+So the details would need to be flushed out during the community bonding
+period and as the implementation progresses. However I’m confident that a
+satisfactory solution can be designed.
+
+Using these new features, the example above could be rewritten as:
+
+    import org.gnu.hurd.InitPorts;
+    import org.gnu.hurd.Io;
+    import org.gnu.hurd.IoUser;
+
+    class Hello {
+       static void main(String argv[]) throws ...
+       {
+           Io stdout = new IoUser(InitPorts.getdport(1));
+           String hello = “Hello, World!\n”;
+
+           int amount = stdout.write(hello.getBytes(), -1);
+
+           /* (A retCode corresponding to an error
+               would be signalled as an exception.) */
+       }
+    }
+
+An example of server implementation would be:
+
+    import org.gnu.hurd.Io;
+    import java.util.Arrays;
+
+    class HelloIo implements Io {
+       final byte[] contents = “Hello, World!\n”.getBytes();
+
+       int write(byte[] data, int offset) {
+           return SOME_ERROR_CODE;
+       }
+
+       byte[] read(int offset, int amount) {
+           return Arrays.copyOfRange(contents, offset,
+                                     offset + amount - 1);
+       }
+
+       /* ... */
+    }
+
+A new server object could then be created with `new IoServer(new HelloIo())`,
+and associated with some receive right at the level of the ports management
+library.
+
+### Base classes for common types of translators
+
+Once MIG can target Java code, and a libports equivalent is available,
+creating new translators in Java would be greatly facilitated. However,
+we would probably want to introduce basic implementations of file system
+translators in the spirit of libtrivfs or libnetfs. They could take the form
+of base classes implementing the relevant MIG-generated interfaces which
+would then be derived by users,
+or could define a simpler interface
+which would then be used by adapter classes
+to implement the required ones.
+
+I would draw inspiration from libtrivfs and libnetfs
+to design and implement similar solutions for Java.
+
+### Deliverables
+
+  * A hurd-java package would contain the Java code developed
+    in the context of this project.
+  * The Java code would be documented using javadoc
+    and a tutorial for writing translators would be written as well.
+  * Modifications to MIG would be submitted upstream,
+    or a patched MIG package would be made available.
+
+The Java libraries resulting from this work,
+including any MIG support classes
+as well as the class files built from the MIG-generated code
+for the Mach and Hurd interface definition files,
+would be provided as single `hurd-java` package for
+Debian GNU/Hurd.
+This package would be separate from both Hurd and Mach,
+so as not to impose unreasonable build dependencies on them.
+
+I expect I would be able to act as its maintainer in the foreseeable future, 
+either as an individual or as a part of the Hurd team.
+Hopefully,
+my code would be claimed by the Hurd project as their own,
+and consequently the modifications to MIG
+(which would at least conceptually depend on the Mach Java package)
+could be integrated upstream.
+
+Since by design,
+the Java code would use only a small number of stable interfaces,
+it would not be subject to excessive amounts of bitrot.
+Consequently,
+maintenance would primarily consist in
+fixing bugs as they are reported,
+and adding new features as they are requested.
+A large number of such requests
+would mean the package is useful,
+so I expect that the overall amount of work
+would be correlated with the willingness of more people
+to help with maintenance
+should I become overwhelmed or get hit by a bus.
+
+
+## Timeline
+
+The dates listed are deadlines for the associated tasks.
+
+  * *Community bonding period.*
+    Discuss, refine and complete the design of the Java bindings
+    (in particular the MIG and "libports" parts)
+  * *May 23.*
+    Coding starts.
+  * *May 30.*
+    Finish implementing pthread signal semantics.
+  * *June 5.*
+    Port OpenJDK
+  * *June 12.*
+    Fix the remaining problems with GCJ and/or OpenJDK,
+    possibly port Eclipse or other big Java packages.
+  * *June 19.*
+    Create the bindings for Mach.
+  * *June 26.*
+    Work on some kind of basic Java libports
+    to handle receive rights.
+  * *July 3.*
+    Test, write some documentation and examples.
+  * *July 17 (two weeks).*
+    Add the Java target to MIG.
+  * *July 24.*
+    Test, write some documentation and examples.
+  * *August 7 (two weeks).*
+    Implement a modular libfoofs to help with translator development.
+    Try to write a basic but non-trivial translator
+    to evaluate the performance and ease of use of the result,
+    rectify any rough edges this would uncover.
+  * *August 22. (last two weeks)*
+    Polish the code and packaging,
+    finish writing the documentation.
+
+
+## Conclusion
+
+This project is arguably ambitious.
+However, I have been thinking about it for some time now
+and I'm confident I would be able to accomplish most of it.
+
+In the event multiple language bindings projects
+would be accepted,
+some work could probably be done in common.
+In particular,
+[ArneBab](http://www.bddebian.com/~hurd-web/community/weblogs/ArneBab/2011-04-06-application-pyhurd/)
+seems to favor a low-level approach for his Python bindings as I do for Java,
+and I would be happy to discuss API design and coordinate MIG changes with him.
+I would also have an extra month after the end of the GSoC period
+before I go back to school,
+which I would be able to use to finish the project
+if there is some remaining work.
+(Last year's rewrite of procfs was done during this period.)
+
+As for the project's benefits,
+I believe that good support for Java
+is a must-have for the Hurd.
+Java bindings would also further the Hurd's agenda
+of user freedom by extending this freedom to more people:
+I expect the set of developers
+who would be able to write Java code against a well-written libfoofs
+is much larger than
+those who master the intricacies of low-level systems C programming.
+From a more strategic point of view,
+this would also help recruit new contributors
+by providing an easier path to learning the inner workings of the Hurd.
+
+Further developments
+which would build on the results of this project
+include my planned [[experiment with Joe-E|objcap]]
+(which I would possibly take on as a university project next year).
+Another possibility would be to reimplement some parts
+of the Java standard library
+directly in terms of the Hurd interfaces
+instead of using the POSIX ones through glibc.
+This would possibly improve the performance
+of some Java applications (though probably not by much),
+and would otherwise be a good project
+for someone trying to get acquainted with Hurd.
+
+Overall, I believe this project would be fun, interesting and useful.
+I hope that you will share this sentiment
+and give me the opportunity to spend another summer working on Hurd.
+