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+[[!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_classes.dia b/user/jkoenig/gsoc2011_classes.dia
new file mode 100644
index 00000000..1aa3ef6c
--- /dev/null
+++ b/user/jkoenig/gsoc2011_classes.dia
@@ -0,0 +1,2227 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<dia:diagram xmlns:dia="http://www.lysator.liu.se/~alla/dia/">
+ <dia:diagramdata>
+ <dia:attribute name="background">
+ <dia:color val="#ffffff"/>
+ </dia:attribute>
+ <dia:attribute name="pagebreak">
+ <dia:color val="#000099"/>
+ </dia:attribute>
+ <dia:attribute name="paper">
+ <dia:composite type="paper">
+ <dia:attribute name="name">
+ <dia:string>#A4#</dia:string>
+ </dia:attribute>
+ <dia:attribute name="tmargin">
+ <dia:real val="2.8222000598907471"/>
+ </dia:attribute>
+ <dia:attribute name="bmargin">
+ <dia:real val="2.8222000598907471"/>
+ </dia:attribute>
+ <dia:attribute name="lmargin">
+ <dia:real val="2.8222000598907471"/>
+ </dia:attribute>
+ <dia:attribute name="rmargin">
+ <dia:real val="2.8222000598907471"/>
+ </dia:attribute>
+ <dia:attribute name="is_portrait">
+ <dia:boolean val="true"/>
+ </dia:attribute>
+ <dia:attribute name="scaling">
+ <dia:real val="1"/>
+ </dia:attribute>
+ <dia:attribute name="fitto">
+ <dia:boolean val="false"/>
+ </dia:attribute>
+ </dia:composite>
+ </dia:attribute>
+ <dia:attribute name="grid">
+ <dia:composite type="grid">
+ <dia:attribute name="width_x">
+ <dia:real val="1"/>
+ </dia:attribute>
+ <dia:attribute name="width_y">
+ <dia:real val="1"/>
+ </dia:attribute>
+ <dia:attribute name="visible_x">
+ <dia:int val="1"/>
+ </dia:attribute>
+ <dia:attribute name="visible_y">
+ <dia:int val="1"/>
+ </dia:attribute>
+ <dia:composite type="color"/>
+ </dia:composite>
+ </dia:attribute>
+ <dia:attribute name="color">
+ <dia:color val="#d8e5e5"/>
+ </dia:attribute>
+ <dia:attribute name="guides">
+ <dia:composite type="guides">
+ <dia:attribute name="hguides"/>
+ <dia:attribute name="vguides"/>
+ </dia:composite>
+ </dia:attribute>
+ </dia:diagramdata>
+ <dia:layer name="Arrière-plan" visible="true" active="true">
+ <dia:group>
+ <dia:object type="UML - LargePackage" version="0" id="O0">
+ <dia:attribute name="obj_pos">
+ <dia:point val="43.3541,9.67669"/>
+ </dia:attribute>
+ <dia:attribute name="obj_bb">
+ <dia:rectangle val="43.3041,8.62669;62.3869,21.8152"/>
+ </dia:attribute>
+ <dia:attribute name="meta">
+ <dia:composite type="dict"/>
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+ <dia:attribute name="elem_corner">
+ <dia:point val="43.3541,9.67669"/>
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+ <dia:attribute name="elem_width">
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+ <dia:attribute name="line_width">
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+ <dia:color val="#ffffff"/>
+ </dia:attribute>
+ <dia:attribute name="text_colour">
+ <dia:color val="#000000"/>
+ </dia:attribute>
+ <dia:attribute name="stereotype">
+ <dia:string>##</dia:string>
+ </dia:attribute>
+ <dia:attribute name="name">
+ <dia:string>#User-defined classes#</dia:string>
+ </dia:attribute>
+ </dia:object>
+ <dia:object type="UML - Class" version="0" id="O1">
+ <dia:attribute name="obj_pos">
+ <dia:point val="46.0492,12.9799"/>
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+ <dia:rectangle val="45.9992,12.9299;60.4592,18.4299"/>
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+ <dia:attribute name="elem_corner">
+ <dia:point val="46.0492,12.9799"/>
+ </dia:attribute>
+ <dia:attribute name="elem_width">
+ <dia:real val="14.359999999999999"/>
+ </dia:attribute>
+ <dia:attribute name="elem_height">
+ <dia:real val="5.4000000000000004"/>
+ </dia:attribute>
+ <dia:attribute name="name">
+ <dia:string>#HelloIo#</dia:string>
+ </dia:attribute>
+ <dia:attribute name="stereotype">
+ <dia:string>##</dia:string>
+ </dia:attribute>
+ <dia:attribute name="comment">
+ <dia:string>#Implements a file which always contains "Hello, World!\n"#</dia:string>
+ </dia:attribute>
+ <dia:attribute name="abstract">
+ <dia:boolean val="false"/>
+ </dia:attribute>
+ <dia:attribute name="suppress_attributes">
+ <dia:boolean val="false"/>
+ </dia:attribute>
+ <dia:attribute name="suppress_operations">
+ <dia:boolean val="false"/>
+ </dia:attribute>
+ <dia:attribute name="visible_attributes">
+ <dia:boolean val="false"/>
+ </dia:attribute>
+ <dia:attribute name="visible_operations">
+ <dia:boolean val="true"/>
+ </dia:attribute>
+ <dia:attribute name="visible_comments">
+ <dia:boolean val="true"/>
+ </dia:attribute>
+ <dia:attribute name="wrap_operations">
+ <dia:boolean val="true"/>
+ </dia:attribute>
+ <dia:attribute name="wrap_after_char">
+ <dia:int val="40"/>
+ </dia:attribute>
+ <dia:attribute name="comment_line_length">
+ <dia:int val="40"/>
+ </dia:attribute>
+ <dia:attribute name="comment_tagging">
+ <dia:boolean val="false"/>
+ </dia:attribute>
+ <dia:attribute name="line_width">
+ <dia:real val="0.10000000000000001"/>
+ </dia:attribute>
+ <dia:attribute name="line_color">
+ <dia:color val="#000000"/>
+ </dia:attribute>
+ <dia:attribute name="fill_color">
+ <dia:color val="#ffffff"/>
+ </dia:attribute>
+ <dia:attribute name="text_color">
+ <dia:color val="#000000"/>
+ </dia:attribute>
+ <dia:attribute name="normal_font">
+ <dia:font family="monospace" style="0" name="Courier"/>
+ </dia:attribute>
+ <dia:attribute name="abstract_font">
+ <dia:font family="monospace" style="88" name="Courier-BoldOblique"/>
+ </dia:attribute>
+ <dia:attribute name="polymorphic_font">
+ <dia:font family="monospace" style="8" name="Courier-Oblique"/>
+ </dia:attribute>
+ <dia:attribute name="classname_font">
+ <dia:font family="sans" style="80" name="Helvetica-Bold"/>
+ </dia:attribute>
+ <dia:attribute name="abstract_classname_font">
+ <dia:font family="sans" style="88" name="Helvetica-BoldOblique"/>
+ </dia:attribute>
+ <dia:attribute name="comment_font">
+ <dia:font family="sans" style="8" name="Helvetica-Oblique"/>
+ </dia:attribute>
+ <dia:attribute name="normal_font_height">
+ <dia:real val="0.80000000000000004"/>
+ </dia:attribute>
+ <dia:attribute name="polymorphic_font_height">
+ <dia:real val="0.80000000000000004"/>
+ </dia:attribute>
+ <dia:attribute name="abstract_font_height">
+ <dia:real val="0.80000000000000004"/>
+ </dia:attribute>
+ <dia:attribute name="classname_font_height">
+ <dia:real val="1"/>
+ </dia:attribute>
+ <dia:attribute name="abstract_classname_font_height">
+ <dia:real val="1"/>
+ </dia:attribute>
+ <dia:attribute name="comment_font_height">
+ <dia:real val="0.69999999999999996"/>
+ </dia:attribute>
+ <dia:attribute name="attributes"/>
+ <dia:attribute name="operations">
+ <dia:composite type="umloperation">
+ <dia:attribute name="name">
+ <dia:string>#write#</dia:string>
+ </dia:attribute>
+ <dia:attribute name="stereotype">
+ <dia:string>##</dia:string>
+ </dia:attribute>
+ <dia:attribute name="type">
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+ </dia:attribute>
+ <dia:attribute name="attributes"/>
+ <dia:attribute name="operations">
+ <dia:composite type="umloperation">
+ <dia:attribute name="name">
+ <dia:string>#handle#</dia:string>
+ </dia:attribute>
+ <dia:attribute name="stereotype">
+ <dia:string>##</dia:string>
+ </dia:attribute>
+ <dia:attribute name="type">
+ <dia:string>#Message#</dia:string>
+ </dia:attribute>
+ <dia:attribute name="visibility">
+ <dia:enum val="0"/>
+ </dia:attribute>
+ <dia:attribute name="comment">
+ <dia:string>##</dia:string>
+ </dia:attribute>
+ <dia:attribute name="abstract">
+ <dia:boolean val="false"/>
+ </dia:attribute>
+ <dia:attribute name="inheritance_type">
+ <dia:enum val="2"/>
+ </dia:attribute>
+ <dia:attribute name="query">
+ <dia:boolean val="false"/>
+ </dia:attribute>
+ <dia:attribute name="class_scope">
+ <dia:boolean val="false"/>
+ </dia:attribute>
+ <dia:attribute name="parameters">
+ <dia:composite type="umlparameter">
+ <dia:attribute name="name">
+ <dia:string>#msg#</dia:string>
+ </dia:attribute>
+ <dia:attribute name="type">
+ <dia:string>#Message#</dia:string>
+ </dia:attribute>
+ <dia:attribute name="value">
+ <dia:string>##</dia:string>
+ </dia:attribute>
+ <dia:attribute name="comment">
+ <dia:string>##</dia:string>
+ </dia:attribute>
+ <dia:attribute name="kind">
+ <dia:enum val="0"/>
+ </dia:attribute>
+ </dia:composite>
+ </dia:attribute>
+ </dia:composite>
+ </dia:attribute>
+ <dia:attribute name="template">
+ <dia:boolean val="false"/>
+ </dia:attribute>
+ <dia:attribute name="templates"/>
+ </dia:object>
+ <dia:object type="UML - Class" version="0" id="O11">
+ <dia:attribute name="obj_pos">
+ <dia:point val="4.78285,12.2997"/>
+ </dia:attribute>
+ <dia:attribute name="obj_bb">
+ <dia:rectangle val="4.73285,12.2497;16.4978,15.5497"/>
+ </dia:attribute>
+ <dia:attribute name="elem_corner">
+ <dia:point val="4.78285,12.2997"/>
+ </dia:attribute>
+ <dia:attribute name="elem_width">
+ <dia:real val="11.664999999999999"/>
+ </dia:attribute>
+ <dia:attribute name="elem_height">
+ <dia:real val="3.2000000000000002"/>
+ </dia:attribute>
+ <dia:attribute name="name">
+ <dia:string>#Demux#</dia:string>
+ </dia:attribute>
+ <dia:attribute name="stereotype">
+ <dia:string>##</dia:string>
+ </dia:attribute>
+ <dia:attribute name="comment">
+ <dia:string>##</dia:string>
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+ <dia:attribute name="abstract">
+ <dia:boolean val="false"/>
+ </dia:attribute>
+ <dia:attribute name="suppress_attributes">
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+ <dia:attribute name="suppress_operations">
+ <dia:boolean val="false"/>
+ </dia:attribute>
+ <dia:attribute name="visible_attributes">
+ <dia:boolean val="false"/>
+ </dia:attribute>
+ <dia:attribute name="visible_operations">
+ <dia:boolean val="true"/>
+ </dia:attribute>
+ <dia:attribute name="visible_comments">
+ <dia:boolean val="false"/>
+ </dia:attribute>
+ <dia:attribute name="wrap_operations">
+ <dia:boolean val="true"/>
+ </dia:attribute>
+ <dia:attribute name="wrap_after_char">
+ <dia:int val="40"/>
+ </dia:attribute>
+ <dia:attribute name="comment_line_length">
+ <dia:int val="17"/>
+ </dia:attribute>
+ <dia:attribute name="comment_tagging">
+ <dia:boolean val="false"/>
+ </dia:attribute>
+ <dia:attribute name="line_width">
+ <dia:real val="0.10000000000000001"/>
+ </dia:attribute>
+ <dia:attribute name="line_color">
+ <dia:color val="#000000"/>
+ </dia:attribute>
+ <dia:attribute name="fill_color">
+ <dia:color val="#ffffff"/>
+ </dia:attribute>
+ <dia:attribute name="text_color">
+ <dia:color val="#000000"/>
+ </dia:attribute>
+ <dia:attribute name="normal_font">
+ <dia:font family="monospace" style="0" name="Courier"/>
+ </dia:attribute>
+ <dia:attribute name="abstract_font">
+ <dia:font family="monospace" style="88" name="Courier-BoldOblique"/>
+ </dia:attribute>
+ <dia:attribute name="polymorphic_font">
+ <dia:font family="monospace" style="8" name="Courier-Oblique"/>
+ </dia:attribute>
+ <dia:attribute name="classname_font">
+ <dia:font family="sans" style="80" name="Helvetica-Bold"/>
+ </dia:attribute>
+ <dia:attribute name="abstract_classname_font">
+ <dia:font family="sans" style="88" name="Helvetica-BoldOblique"/>
+ </dia:attribute>
+ <dia:attribute name="comment_font">
+ <dia:font family="sans" style="8" name="Helvetica-Oblique"/>
+ </dia:attribute>
+ <dia:attribute name="normal_font_height">
+ <dia:real val="0.80000000000000004"/>
+ </dia:attribute>
+ <dia:attribute name="polymorphic_font_height">
+ <dia:real val="0.80000000000000004"/>
+ </dia:attribute>
+ <dia:attribute name="abstract_font_height">
+ <dia:real val="0.80000000000000004"/>
+ </dia:attribute>
+ <dia:attribute name="classname_font_height">
+ <dia:real val="1"/>
+ </dia:attribute>
+ <dia:attribute name="abstract_classname_font_height">
+ <dia:real val="1"/>
+ </dia:attribute>
+ <dia:attribute name="comment_font_height">
+ <dia:real val="0.69999999999999996"/>
+ </dia:attribute>
+ <dia:attribute name="attributes"/>
+ <dia:attribute name="operations">
+ <dia:composite type="umloperation">
+ <dia:attribute name="name">
+ <dia:string>#addServer#</dia:string>
+ </dia:attribute>
+ <dia:attribute name="stereotype">
+ <dia:string>##</dia:string>
+ </dia:attribute>
+ <dia:attribute name="type">
+ <dia:string>##</dia:string>
+ </dia:attribute>
+ <dia:attribute name="visibility">
+ <dia:enum val="0"/>
+ </dia:attribute>
+ <dia:attribute name="comment">
+ <dia:string>##</dia:string>
+ </dia:attribute>
+ <dia:attribute name="abstract">
+ <dia:boolean val="false"/>
+ </dia:attribute>
+ <dia:attribute name="inheritance_type">
+ <dia:enum val="2"/>
+ </dia:attribute>
+ <dia:attribute name="query">
+ <dia:boolean val="false"/>
+ </dia:attribute>
+ <dia:attribute name="class_scope">
+ <dia:boolean val="false"/>
+ </dia:attribute>
+ <dia:attribute name="parameters">
+ <dia:composite type="umlparameter">
+ <dia:attribute name="name">
+ <dia:string>#s#</dia:string>
+ </dia:attribute>
+ <dia:attribute name="type">
+ <dia:string>#Server#</dia:string>
+ </dia:attribute>
+ <dia:attribute name="value">
+ <dia:string>##</dia:string>
+ </dia:attribute>
+ <dia:attribute name="comment">
+ <dia:string>##</dia:string>
+ </dia:attribute>
+ <dia:attribute name="kind">
+ <dia:enum val="0"/>
+ </dia:attribute>
+ </dia:composite>
+ </dia:attribute>
+ </dia:composite>
+ <dia:composite type="umloperation">
+ <dia:attribute name="name">
+ <dia:string>#handle#</dia:string>
+ </dia:attribute>
+ <dia:attribute name="stereotype">
+ <dia:string>##</dia:string>
+ </dia:attribute>
+ <dia:attribute name="type">
+ <dia:string>#Message#</dia:string>
+ </dia:attribute>
+ <dia:attribute name="visibility">
+ <dia:enum val="0"/>
+ </dia:attribute>
+ <dia:attribute name="comment">
+ <dia:string>##</dia:string>
+ </dia:attribute>
+ <dia:attribute name="abstract">
+ <dia:boolean val="false"/>
+ </dia:attribute>
+ <dia:attribute name="inheritance_type">
+ <dia:enum val="2"/>
+ </dia:attribute>
+ <dia:attribute name="query">
+ <dia:boolean val="false"/>
+ </dia:attribute>
+ <dia:attribute name="class_scope">
+ <dia:boolean val="false"/>
+ </dia:attribute>
+ <dia:attribute name="parameters">
+ <dia:composite type="umlparameter">
+ <dia:attribute name="name">
+ <dia:string>#msg#</dia:string>
+ </dia:attribute>
+ <dia:attribute name="type">
+ <dia:string>#Message#</dia:string>
+ </dia:attribute>
+ <dia:attribute name="value">
+ <dia:string>##</dia:string>
+ </dia:attribute>
+ <dia:attribute name="comment">
+ <dia:string>##</dia:string>
+ </dia:attribute>
+ <dia:attribute name="kind">
+ <dia:enum val="0"/>
+ </dia:attribute>
+ </dia:composite>
+ </dia:attribute>
+ </dia:composite>
+ </dia:attribute>
+ <dia:attribute name="template">
+ <dia:boolean val="false"/>
+ </dia:attribute>
+ <dia:attribute name="templates"/>
+ <dia:childnode parent="O9"/>
+ </dia:object>
+ <dia:object type="UML - Association" version="2" id="O12">
+ <dia:attribute name="name">
+ <dia:string>##</dia:string>
+ </dia:attribute>
+ <dia:attribute name="direction">
+ <dia:enum val="1"/>
+ </dia:attribute>
+ <dia:attribute name="show_direction">
+ <dia:boolean val="false"/>
+ </dia:attribute>
+ <dia:attribute name="assoc_type">
+ <dia:enum val="1"/>
+ </dia:attribute>
+ <dia:attribute name="role_a">
+ <dia:string>##</dia:string>
+ </dia:attribute>
+ <dia:attribute name="multipicity_a">
+ <dia:string>##</dia:string>
+ </dia:attribute>
+ <dia:attribute name="visibility_a">
+ <dia:enum val="3"/>
+ </dia:attribute>
+ <dia:attribute name="show_arrow_a">
+ <dia:boolean val="false"/>
+ </dia:attribute>
+ <dia:attribute name="role_b">
+ <dia:string>##</dia:string>
+ </dia:attribute>
+ <dia:attribute name="multipicity_b">
+ <dia:string>##</dia:string>
+ </dia:attribute>
+ <dia:attribute name="visibility_b">
+ <dia:enum val="3"/>
+ </dia:attribute>
+ <dia:attribute name="show_arrow_b">
+ <dia:boolean val="false"/>
+ </dia:attribute>
+ <dia:attribute name="obj_pos">
+ <dia:point val="4.78285,12.9997"/>
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+ <dia:attribute name="obj_bb">
+ <dia:rectangle val="2.75192,6.54761;5.53285,14.5997"/>
+ </dia:attribute>
+ <dia:attribute name="meta">
+ <dia:composite type="dict"/>
+ </dia:attribute>
+ <dia:attribute name="orth_points">
+ <dia:point val="4.78285,12.9997"/>
+ <dia:point val="2.80192,12.9997"/>
+ <dia:point val="2.80192,6.59761"/>
+ <dia:point val="4.78285,6.59761"/>
+ </dia:attribute>
+ <dia:attribute name="orth_orient">
+ <dia:enum val="0"/>
+ <dia:enum val="1"/>
+ <dia:enum val="0"/>
+ </dia:attribute>
+ <dia:attribute name="orth_autoroute">
+ <dia:boolean val="false"/>
+ </dia:attribute>
+ <dia:attribute name="text_colour">
+ <dia:color val="#000000"/>
+ </dia:attribute>
+ <dia:attribute name="line_colour">
+ <dia:color val="#000000"/>
+ </dia:attribute>
+ <dia:connections>
+ <dia:connection handle="0" to="O11" connection="3"/>
+ <dia:connection handle="1" to="O10" connection="3"/>
+ </dia:connections>
+ <dia:childnode parent="O9"/>
+ </dia:object>
+ <dia:object type="UML - Note" version="0" id="O13">
+ <dia:attribute name="obj_pos">
+ <dia:point val="5.16035,19.1017"/>
+ </dia:attribute>
+ <dia:attribute name="obj_bb">
+ <dia:rectangle val="5.11035,19.0517;16.1203,22.4517"/>
+ </dia:attribute>
+ <dia:attribute name="meta">
+ <dia:composite type="dict"/>
+ </dia:attribute>
+ <dia:attribute name="elem_corner">
+ <dia:point val="5.16035,19.1017"/>
+ </dia:attribute>
+ <dia:attribute name="elem_width">
+ <dia:real val="10.91"/>
+ </dia:attribute>
+ <dia:attribute name="elem_height">
+ <dia:real val="3.3000000000000003"/>
+ </dia:attribute>
+ <dia:attribute name="line_width">
+ <dia:real val="0.10000000000000001"/>
+ </dia:attribute>
+ <dia:attribute name="line_colour">
+ <dia:color val="#000000"/>
+ </dia:attribute>
+ <dia:attribute name="fill_colour">
+ <dia:color val="#ffffff"/>
+ </dia:attribute>
+ <dia:attribute name="text">
+ <dia:composite type="text">
+ <dia:attribute name="string">
+ <dia:string>#Plus some kind of port set
+support and a way to start
+a server thread.#</dia:string>
+ </dia:attribute>
+ <dia:attribute name="font">
+ <dia:font family="monospace" style="0" name="Courier"/>
+ </dia:attribute>
+ <dia:attribute name="height">
+ <dia:real val="0.80000000000000004"/>
+ </dia:attribute>
+ <dia:attribute name="pos">
+ <dia:point val="5.51035,20.3467"/>
+ </dia:attribute>
+ <dia:attribute name="color">
+ <dia:color val="#000000"/>
+ </dia:attribute>
+ <dia:attribute name="alignment">
+ <dia:enum val="0"/>
+ </dia:attribute>
+ </dia:composite>
+ </dia:attribute>
+ <dia:childnode parent="O9"/>
+ </dia:object>
+ <dia:object type="UML - Realizes" version="1" id="O14">
+ <dia:attribute name="obj_pos">
+ <dia:point val="10.6153,8.74801"/>
+ </dia:attribute>
+ <dia:attribute name="obj_bb">
+ <dia:rectangle val="10.5653,8.74801;10.7153,12.32"/>
+ </dia:attribute>
+ <dia:attribute name="meta">
+ <dia:composite type="dict"/>
+ </dia:attribute>
+ <dia:attribute name="orth_points">
+ <dia:point val="10.6153,8.74801"/>
+ <dia:point val="10.6153,8.74801"/>
+ <dia:point val="10.6153,12.2493"/>
+ <dia:point val="10.6153,12.2493"/>
+ </dia:attribute>
+ <dia:attribute name="orth_orient">
+ <dia:enum val="0"/>
+ <dia:enum val="1"/>
+ <dia:enum val="0"/>
+ </dia:attribute>
+ <dia:attribute name="orth_autoroute">
+ <dia:boolean val="true"/>
+ </dia:attribute>
+ <dia:attribute name="line_colour">
+ <dia:color val="#000000"/>
+ </dia:attribute>
+ <dia:attribute name="text_colour">
+ <dia:color val="#000000"/>
+ </dia:attribute>
+ <dia:attribute name="name">
+ <dia:string>##</dia:string>
+ </dia:attribute>
+ <dia:attribute name="stereotype">
+ <dia:string>##</dia:string>
+ </dia:attribute>
+ <dia:connections>
+ <dia:connection handle="0" to="O10" connection="10"/>
+ <dia:connection handle="1" to="O11" connection="12"/>
+ </dia:connections>
+ <dia:childnode parent="O9"/>
+ </dia:object>
+ </dia:group>
+ <dia:object type="UML - Note" version="0" id="O15">
+ <dia:attribute name="obj_pos">
+ <dia:point val="29.2528,-4.64872"/>
+ </dia:attribute>
+ <dia:attribute name="obj_bb">
+ <dia:rectangle val="29.2028,-4.69872;32.8978,-2.89872"/>
+ </dia:attribute>
+ <dia:attribute name="meta">
+ <dia:composite type="dict"/>
+ </dia:attribute>
+ <dia:attribute name="elem_corner">
+ <dia:point val="29.2528,-4.64872"/>
+ </dia:attribute>
+ <dia:attribute name="elem_width">
+ <dia:real val="3.5949999999999998"/>
+ </dia:attribute>
+ <dia:attribute name="elem_height">
+ <dia:real val="1.7"/>
+ </dia:attribute>
+ <dia:attribute name="line_width">
+ <dia:real val="0.10000000000000001"/>
+ </dia:attribute>
+ <dia:attribute name="line_colour">
+ <dia:color val="#000000"/>
+ </dia:attribute>
+ <dia:attribute name="fill_colour">
+ <dia:color val="#ffffff"/>
+ </dia:attribute>
+ <dia:attribute name="text">
+ <dia:composite type="text">
+ <dia:attribute name="string">
+ <dia:string>#io.defs#</dia:string>
+ </dia:attribute>
+ <dia:attribute name="font">
+ <dia:font family="monospace" style="0" name="Courier"/>
+ </dia:attribute>
+ <dia:attribute name="height">
+ <dia:real val="0.80000000000000004"/>
+ </dia:attribute>
+ <dia:attribute name="pos">
+ <dia:point val="29.6028,-3.40372"/>
+ </dia:attribute>
+ <dia:attribute name="color">
+ <dia:color val="#000000"/>
+ </dia:attribute>
+ <dia:attribute name="alignment">
+ <dia:enum val="0"/>
+ </dia:attribute>
+ </dia:composite>
+ </dia:attribute>
+ </dia:object>
+ <dia:object type="UML - Dependency" version="1" id="O16">
+ <dia:attribute name="obj_pos">
+ <dia:point val="31.0503,-2.94872"/>
+ </dia:attribute>
+ <dia:attribute name="obj_bb">
+ <dia:rectangle val="31.0003,-2.94872;32.3053,1.26212"/>
+ </dia:attribute>
+ <dia:attribute name="meta">
+ <dia:composite type="dict"/>
+ </dia:attribute>
+ <dia:attribute name="orth_points">
+ <dia:point val="31.0503,-2.94872"/>
+ <dia:point val="31.0503,-2.94872"/>
+ <dia:point val="31.0503,1.19141"/>
+ <dia:point val="31.0503,1.19141"/>
+ </dia:attribute>
+ <dia:attribute name="orth_orient">
+ <dia:enum val="0"/>
+ <dia:enum val="1"/>
+ <dia:enum val="0"/>
+ </dia:attribute>
+ <dia:attribute name="orth_autoroute">
+ <dia:boolean val="true"/>
+ </dia:attribute>
+ <dia:attribute name="text_colour">
+ <dia:color val="#000000"/>
+ </dia:attribute>
+ <dia:attribute name="line_colour">
+ <dia:color val="#000000"/>
+ </dia:attribute>
+ <dia:attribute name="name">
+ <dia:string>#mig#</dia:string>
+ </dia:attribute>
+ <dia:attribute name="stereotype">
+ <dia:string>##</dia:string>
+ </dia:attribute>
+ <dia:attribute name="draw_arrow">
+ <dia:boolean val="true"/>
+ </dia:attribute>
+ <dia:connections>
+ <dia:connection handle="0" to="O15" connection="6"/>
+ <dia:connection handle="1" to="O2" connection="1"/>
+ </dia:connections>
+ </dia:object>
+ <dia:object type="UML - Realizes" version="1" id="O17">
+ <dia:attribute name="obj_pos">
+ <dia:point val="38.6094,14.4231"/>
+ </dia:attribute>
+ <dia:attribute name="obj_bb">
+ <dia:rectangle val="38.5594,13.5731;46.0992,16.0015"/>
+ </dia:attribute>
+ <dia:attribute name="meta">
+ <dia:composite type="dict"/>
+ </dia:attribute>
+ <dia:attribute name="orth_points">
+ <dia:point val="38.6094,14.4231"/>
+ <dia:point val="42.3293,14.4231"/>
+ <dia:point val="42.3293,14.3799"/>
+ <dia:point val="46.0492,14.3799"/>
+ </dia:attribute>
+ <dia:attribute name="orth_orient">
+ <dia:enum val="0"/>
+ <dia:enum val="1"/>
+ <dia:enum val="0"/>
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+ <dia:attribute name="orth_autoroute">
+ <dia:boolean val="true"/>
+ </dia:attribute>
+ <dia:attribute name="line_colour">
+ <dia:color val="#000000"/>
+ </dia:attribute>
+ <dia:attribute name="text_colour">
+ <dia:color val="#000000"/>
+ </dia:attribute>
+ <dia:attribute name="name">
+ <dia:string>##</dia:string>
+ </dia:attribute>
+ <dia:attribute name="stereotype">
+ <dia:string>##</dia:string>
+ </dia:attribute>
+ <dia:connections>
+ <dia:connection handle="0" to="O4" connection="4"/>
+ <dia:connection handle="1" to="O1" connection="3"/>
+ </dia:connections>
+ </dia:object>
+ <dia:object type="UML - Realizes" version="1" id="O18">
+ <dia:attribute name="obj_pos">
+ <dia:point val="16.4478,6.59761"/>
+ </dia:attribute>
+ <dia:attribute name="obj_bb">
+ <dia:rectangle val="16.3978,5.74761;24.9476,8.17255"/>
+ </dia:attribute>
+ <dia:attribute name="meta">
+ <dia:composite type="dict"/>
+ </dia:attribute>
+ <dia:attribute name="orth_points">
+ <dia:point val="16.4478,6.59761"/>
+ <dia:point val="20.4657,6.59761"/>
+ <dia:point val="20.4657,6.54749"/>
+ <dia:point val="24.8976,6.54749"/>
+ </dia:attribute>
+ <dia:attribute name="orth_orient">
+ <dia:enum val="0"/>
+ <dia:enum val="1"/>
+ <dia:enum val="0"/>
+ </dia:attribute>
+ <dia:attribute name="orth_autoroute">
+ <dia:boolean val="false"/>
+ </dia:attribute>
+ <dia:attribute name="line_colour">
+ <dia:color val="#000000"/>
+ </dia:attribute>
+ <dia:attribute name="text_colour">
+ <dia:color val="#000000"/>
+ </dia:attribute>
+ <dia:attribute name="name">
+ <dia:string>##</dia:string>
+ </dia:attribute>
+ <dia:attribute name="stereotype">
+ <dia:string>##</dia:string>
+ </dia:attribute>
+ <dia:connections>
+ <dia:connection handle="0" to="O10" connection="4"/>
+ <dia:connection handle="1" to="O3" connection="3"/>
+ </dia:connections>
+ </dia:object>
+ </dia:layer>
+</dia:diagram>
diff --git a/user/jkoenig/gsoc2011_classes.png b/user/jkoenig/gsoc2011_classes.png
new file mode 100644
index 00000000..7149b813
--- /dev/null
+++ b/user/jkoenig/gsoc2011_classes.png
Binary files differ
diff --git a/user/jkoenig/gsoc2011_proposal.mdwn b/user/jkoenig/gsoc2011_proposal.mdwn
new file mode 100644
index 00000000..9840f14f
--- /dev/null
+++ b/user/jkoenig/gsoc2011_proposal.mdwn
@@ -0,0 +1,12 @@
+[[!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]]."]]"""]]
+
+This page has moved [[here|java]].
+
diff --git a/user/jkoenig/java.mdwn b/user/jkoenig/java.mdwn
new file mode 100644
index 00000000..e5d288cc
--- /dev/null
+++ b/user/jkoenig/java.mdwn
@@ -0,0 +1,511 @@
+[[!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 stable_URL]]
+
+
+# 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.
+
+
+### 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.
+
+2011-07-20:
+The patches were reviewed by Samuel Thibault.
+Samuel pointed out a couple of issues
+and I beleive I have addressed all of them (fixes posted).
+I'm in the process of publishing updated libc and hurd packages;
+provided those work as expected,
+the next step would be to get these changes into Debian.
+
+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).
+
+IRC, freenode, #hurd, 2011-07-27:
+
+ < jkoenig> the glibc patches are pending review and inclusion in Debian (I
+ think youpi wants to check my latest additions before we go ahead with
+ that)
+ < jkoenig> when it's in Debian and the sky does not fall, I intend to
+ resubmit a full series to libc-alpha for inclusion upstream.
+
+IRC, freenode, #hurd, 2011-08-24:
+
+ < youpi> jkoenig: I'll probably commit your siginfo/globalsig patches soon
+ < youpi> I'm building the ant package atm, seems to proceed great
+ < jkoenig> youpi, great!
+
+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.
+
+ IRC, freenode, #hurd, 2011-08-20:
+
+ < youpi> jkoenig: I was considering renaming the fields of siginfo
+ < youpi> to catch applications which need those which we haven't
+ yet
+ < jkoenig> youpi, makes sense AFAICT
+ < youpi> one issue we'll get is some application which previously
+ built without SA_SIGINFO, and will now want some information
+ we're not yet able to provide
+ < youpi> but at least we'll know
+ < jkoenig> youpi, yes it would still be better than having them
+ crash at runtime because of it
+
+ IRC, freenode, #hurd, 2011-08-21:
+
+ < youpi> jkoenig: actually we need the fields for waitid
+
+ * 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.)
+
+IRC, freenode, #hurd, 2011-07-27:
+
+ < jkoenig> if you have the latest hurd/libc in my repository, you should be
+ able to run /usr/lib/jvm/java-7-openjdk/bin/java without defining
+ LD_ORIGIN_PATH manually
+ < braunr> java: error while loading shared libraries: libjli.so: cannot
+ open shared object file: No such file or directory
+ < jkoenig> braunr, this one is expected, it's the symlink problem.
+ < braunr> oh ok
+ < jkoenig> (ie. thus far, if java is accessed as /usr/bin/java, the ld
+ origin ends up as /usr/bin)
+
+ < jkoenig> *sigh*... it seems I'm going to have to reimplement realpath()
+ in elf/dl-origin.c.
+ < braunr> why ?
+ < jkoenig> using it from there results in duplicate symbols when linking
+ elf/librtld.map.o
+ < braunr> from where ?
+ < braunr> dl-origin ?
+ < jkoenig> apparently this part of the code uses a different allocator
+ (elf/dl-minimal.c)
+ < braunr> oh
+ < braunr> depndency issues ?
+ < braunr> or bootstrapping ones ?
+ < jkoenig> http://paste.debian.net/124310/
+ < jkoenig> dl-origin is what provides the $ORIGIN value for RPATH (now
+ sysdeps/mach/hurd/dl-origin.c, in our case)
+ < braunr> but what's the problem ?
+ < braunr> what prevents you from using the existing implementation ?
+ < jkoenig> you mean copy-and-paste the code ? Well I'll end up doing that I
+ guess... not that it feels right.
+ < braunr> not really
+ < braunr> link against what provides it
+ < braunr> i'm really not familiar with glibc :/
+ < jkoenig> also I'd like to understand what's happening precisely before I
+ resort to such blasphemy :-)
+ < braunr> :)
+ < jkoenig> maybe I could make {file,exec,_hurd}_exec_file_name()
+ canonicalize it instead.
+ < jkoenig> for some reason it does not feel right, though.
+ < braunr> why ?
+ < jkoenig> I'm not sure, loss of information maybe?
+ < jkoenig> (that I ran /usr/bin/java as opposed to /usr/lib/jvm/...)
+ < braunr> i guess you should explain the issue more clearly, i feel like
+ there is something i'm really missing :/
+ < braunr> but it can wait
+ < jkoenig> that ld.so actually needs the canonical file name to substitute
+ $ORIGIN is its own problem, not that of exec or _hurd_exec_file_name..
+ < jkoenig> Ok, so.. Initially the shell (indirectly) runs
+ _hurd_exec_file_name(..., "/usr/bin/java", ...), which then calls
+ file_exec_file_name() on the file in question, passing it its own
+ filename
+ < jkoenig> which is transmitted to exec_exec_file_name()
+ < jkoenig> (until now it's all pochu's patch)
+ < jkoenig> which then makes it available to the newly created process
+ through exec_startup_get_info_2() (my own addition)
+ < braunr> oh
+ < braunr> wasn't it available before oO ?
+ < jkoenig> no, exec only has access to a port to the executable file.
+ < braunr> how was argv[0] handled then ?
+ < jkoenig> argv[0] is handled like any other argument
+ < braunr> ok, so the file path is duplicated ?
+ < jkoenig> the shell (or whomever calls _hurd_exec) provide whatever they
+ want.
+ < braunr> ok
+ < jkoenig> well argv[0] is not necessarily the file path (at least not the
+ full path)
+ < braunr> right
+ < jkoenig> so exec() does some guesswork with $PATH but obviously that's
+ limited.
+ < braunr> so what you changed is that get_info_2 now receives a canonical
+ path ?
+ < jkoenig> right
+ < jkoenig> (or whatever was specified to _hurd_exec_file_name(), for this
+ reason and others we shouldn't use it for setuid programs.)
+ < jkoenig> well, not a canonical path. A path. (hence the problem)
+ < braunr> ok
+ < jkoenig> now both the filesystem and exec might run under another root so
+ they're not an option for canonicalization
+ < jkoenig> _hurd_exec_file_name (in libc) might be a better spot.
+ < braunr> resolution from the client, yes
+
+IRC, freenode, #hurd, 2011-08-03:
+
+ < jkoenig> so my RPATH patches are polished and built, and I'll post them
+ soon, is the good news
+
+IRC, freenode, #hurd, 2011-08-17:
+
+ < jkoenig> also fixed a fakeroot-induced deadlock in my dl-origin patches
+ (namely, under fakeroot, realpath() uses a socket (through stat), so we
+ need to use it when _hurd_dtable_lock is not held)
+ < jkoenig> also I'll post my dl-origin patches shortly
+ < youpi> dl-origin is about the environment variable that java needs,
+ right?
+ < jkoenig> about the environment variable it shouldn't need, yes :-)
+ < youpi> ah :)
+ < youpi> but ok, I vaguely remember what that refers to
+ < jkoenig> $LD_ORIGIN_PATH is used as an override (much like
+ LD_LIBRARY_PATH), but ideally ld.so uses whatever directory the loaded
+ binary is from.
+ < youpi> ok
+ < jkoenig> (as a substitution for $ORIGIN in RPATH)
+
+
+#### 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
+
+IRC, freenode, #hurd, 2011-08-03:
+
+ < jkoenig> and I'm battleing to update my OpenJDK patches to b147, and
+ merge the with the kFreeBSD ones.
+ < braunr> b147 ?
+ < jkoenig> but that thing is seriously huge and touches about everything,
+ so it's taking more time than I'd have hoped
+ < jkoenig> braunr, the latest release of IcedTea / OpenJDK 7 and the
+ current Debian version (in experimental of course)
+ < braunr> ok
+ < jkoenig> I'm trying to make this clean so that hopefully we can get them
+ integrated at some level of upstream (probably IcedTea, at least at
+ first)
+
+IRC, freenode, #hurd, 2011-08-10:
+
+ < jkoenig> well actually I've finished merging my patches with the freebsd
+ ones, and updating them to the new openjdk-7,
+ < jkoenig> but now a new version of both is out :-P
+
+
+##### 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)
+
+ * IRC, freenode, #hurd, 2011-07-27:
+
+ < jkoenig> there's a bug with java.nio when running javadoc, you might
+ run into it.
+
+ * [[`SCM_CREDENTIALS`|open_issues/sendmsg/scm_creds]]
+
+ IRC, freenode, #hurd, 2011-08-03:
+
+ < jkoenig> wrt. peer credentials, openjdk also uses file modes for
+ security, and my guess is that it's sufficient, at least on Hurd, so
+ I've reduced my priority for this at least in the meantime
+
+ * 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.
+
+IRC, freenode, #hurd, 2011-07-27:
+
+ < jkoenig> I need to be able to read/write individual data items from
+ messages, in order to implement deallocation correctly, so I'm working on
+ that when I'm waiting for things to build, but it's not my primary focus
+ right now.
+
+IRC, freenode, #hurd, 2011-08-17:
+
+ < jkoenig> so, weekly status report: I have made some progress on the java
+ bindings, I hope to have a safe version mach_msg soon, after which I can
+ begin experimenting with mig.
+
+
+#### 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..352f6d62
--- /dev/null
+++ b/user/jkoenig/java/discussion.mdwn
@@ -0,0 +1,559 @@
+[[!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]]).
+
+
+# Java Native Interface (JNI)
+
+ * <http://en.wikipedia.org/wiki/Java_Native_Interface>
+ * <http://download.oracle.com/javase/7/docs/technotes/guides/jni/>
+ * <http://java.sun.com/products/jdk/faq/jnifaq.html>
+ * <http://java.sun.com/docs/books/jni/>
+
+
+## Java Native Access (JNA)
+
+ * <http://jna.java.net/>
+ * <https://github.com/twall/jna#readme>
+
+This is a different approach, and *while some attention is paid to performance,
+correctness and ease of use take priority*.
+
+As we plan on only having a few native methods (for invoking `mach_msg`,
+essentially), JNA is probably the wrong approach: portability and ease of use
+is not important, but performance is.
+
+## Compiled Native Interface (CNI)
+
+ * <http://gcc.gnu.org/onlinedocs/gcj/About-CNI.html>
+ * <http://per.bothner.com/papers/UsenixJVM01/CNI01.pdf>
+
+Probably faster than JNI, but only usable with GCJ.
+
+> Given that we have very few JNI calls,
+> it might be interesting to take a "dual" approach
+> if CNI actually improves performance
+> when compiling to native code.
+> --[[jkoenig]] 2011-07-20
+
+# 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..57c87068
--- /dev/null
+++ b/user/jkoenig/java/java-access-bridge.mdwn
@@ -0,0 +1,92 @@
+[[!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
+
+
+IRC, freenode, #hurd, 2011-08-10:
+
+ < jkoenig> and with my latest fix (hardwire os.name as "Linux"),
+ java-access-bridge actually built \o/
+ < youpi> I wouldn't call it a "fix" :)
+ < jkoenig> true, but pretty much everything assumes we're either solaris,
+ linux or windows :-/
+ < jkoenig> also we're actually using the Linux code which it is used to
+ select throughout the JDK
+ < jkoenig> if it's any consolation, os.version stays "GNU-Mach
+ 1.3.99/Hurd-0.3" :-)
+ < youpi> ideally it should simply be changed to "GNU"
diff --git a/user/jkoenig/java/proposal.mdwn b/user/jkoenig/java/proposal.mdwn
new file mode 100644
index 00000000..feb7e9dc
--- /dev/null
+++ b/user/jkoenig/java/proposal.mdwn
@@ -0,0 +1,629 @@
+[[!tag stable_URL]]
+
+# 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.
+
diff --git a/user/jkoenig/objcap.mdwn b/user/jkoenig/objcap.mdwn
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+
+# Potential applications of object-capability languages
+
+The work discussed is this last part would have
+fewer immediate benefits for the Hurd project
+and has more of a research orientation.
+It is also unlikely that there would be any time remaining
+to work on it at the end of the summer.
+(Though it could work as some kind of reward
+if I somehow managed to do a prefect job of all the rest
+within the allocated time :-) ).
+As a consequence,
+I don't really consider this a part of my application.
+
+This being said,
+to some extent the project discussed here
+will informed the way I design the Java bindings,
+since it depends on them
+and I intend to work on this at some point in the future.
+I also believe it touches on some interesting ideas,
+and a Summer of Code application is probably
+as good an occasion as any to discuss them.
+
+### Justification
+
+The primary advantage of multi-server operating systems is the ability to
+break what used to be the kernel into small pieces which can be isolated
+from each others. This makes sense from an engineering perspective, as
+smaller components can be swapped with different implementations and reduce
+the impact of bugs.
+A capability-based approach also ensures that the
+authority wielded by components is clear and reduced to the minimum required
+for them to function.
+These properties are crucial to the Hurd's agenda of user freedom,
+since in order to allow them to plug their own code into the system
+[FIXME: développer]
+
+However, this flexibility has a cost. In a system where the isolation of
+components relies on running them inside different address spaces,
+communication between them must be done through IPC calls.
+This introduces a trade-off between the size of the modules
+and performance as well as practicality,
+which imposes a limit to the granularity with which the system
+can be decomposed and the principle of least authority applied
+(to the code within a given process, a Mach port is ambient authority).
+
+Another issue is that of the threading structure of the system as a whole.
+In systems based on a monolithic kernel, user threads execute the kernel
+code themselves, which is then intrinsically concurrent. By contrast, in a
+system based on a “client-server” paradigm, each server must be explicitly
+multi-threaded if it is to serve requests concurrently.
+
+### Object-capability languages
+
+An object-capability language is an object-oriented language which is
+restricted enough so that object references are themselves capabilities.
+
+One such language is Joe-E (FIXME: lien),
+which is an object-capability subset of Java:
+global state and static methods are mostly forbidden;
+careful white-listing of the objects and methods
+provided by the Java standard library
+ensures that compliant code cannot not access ambient autority.
+Ways in which object references can be transferred
+are restricted to the most obvious ones
+(for instance, exceptions are carefully restricted).
+
+As a result, untrusted Joe-E code can be executed without any further
+isolation and its autority can be controlled by carefully limiting the
+object references which are passed to it.
+This would allow to load and execute translators written in Joe-E
+in a single address space.
+
+### Bundling translators into a single process
+
+[mechanisme pour transmettre le code Joe-E
+et les port initiaux au serveur]
+[émulation des différentes tâches]
+
+### Challenges and further work
+
+[proof-carrying code / typed assembly,
+resource accounting (passer en revue la conception de Viengoos?)]
+
+
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