perl on android

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diff --git a/src/SW/perl-on-android/.gitignore b/src/SW/perl-on-android/.gitignore
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+/document.en.du.xml
+/document.it.du.xml
diff --git a/src/SW/perl-on-android/document.en.rest.txt b/src/SW/perl-on-android/document.en.rest.txt
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+=========================
+Compiling Perl on Android
+=========================
+:CreationDate: 2012-09-01 09:19:00
+:Id: SW/perl-on-android
+:tags: - software
+       - perl
+
+
+At `YAPC::EU 2013`_, I only had my Asus TF101, and I wanted to play
+with some of the modules that the speakers were talking about.
+
+The Google-provided "Perl for Android" (part of the `Android Scripting
+Environment`_) is nearly useless, since you don't get the whole Perl
+core, the CPAN shell does not work, and you don't have a compiler for
+XS modules.
+
+Another option would be to cross-compile from a normal computer, but
+apart from the fact that I did not another computer with me, you still
+would not be able to install XS modules directly from the
+cross-compiled Perl.
+
+So I did what any self-respecting programmer would do: tried to build
+my own. I haven't yet managed to completely build the Perl
+distribution, but I have come some way, and I thought that it would be
+nice to write things down.
+
+Prerequisites
+=============
+
+First of all, you need root access on your device: we have to create
+filesystems, change owners and permissions, mount images.
+
+Then, you need quite some RAM, storage, and processor. I wouldn't try
+it on a phone or a low-powered tablet.
+
+Finally, you need ``busybox``: the bare-bones command line tools
+shipped with most Android images are so limited that not even the very
+conservative Perl ``Configure`` can use them. You'll want to execute
+this (or something similar) to get ``busybox`` binaries in preference
+to the built-in ones::
+
+ export PATH=/system/xbin:$PATH
+
+Preparations
+============
+
+We need a native compiler. I found a well-built ``gcc`` on a wiki
+about ``R``:
+http://rwiki.sciviews.org/doku.php?id=getting-started:installation:android
+
+Get the two ``gcc`` tarballs.
+
+We're going to build a filesystem image, mount it via the loopback
+device, and install everything there: this way, the image can be moved
+between devices (we'll make sure everything is as relocatable as
+possible). I stored everything under ``/data/media/native`` (I created
+that directory). ``/data/media`` is, on my device, the actual store
+that is exposed (via a sort of bind-mount) as ``/sdcard``, with the
+difference that the latter has ``noexec``, the former doesn't.
+
+We want a rather large image, let's say 3 GB. I tried to make a sparse
+file with ``dd if=/dev/zero of=native.e2.diskimg bs=1024 seek=3000000
+count=1`` but it failed. I ended up creating two smaller files and
+concatenating them. Then::
+
+ # cd /data/media/native
+
+ # mke2fs -f native.e2.diskimg
+
+ # cat >  /data/media/native/start <<EOF
+ #!/xbin/ash
+ export PATH=/system/xbin:$PATH
+ BASE="$(dirname "$(readlink -f "$0")")"
+ DEST=/Removable
+ if [[ -d $DEST/fs/bin ]]; then
+    true
+ else
+    mkdir -p $DEST/fs
+    mount -o loop -t ext2 $BASE/native.e2.diskimg $DEST/fs
+ fi
+ echo PATH=\"$DEST/fs/bin:/system/xbin:$PATH\"
+ echo LD_LIBRARY_PATH=\"$DEST/fs/lib\"
+ EOF
+
+ # cat >  /data/media/native/stop <<EOF
+ #!/xbin/ash
+ export PATH=/system/xbin:$PATH
+ BASE="$(dirname "$(readlink -f "$0")")"
+ DEST=/Removable
+ if [[ -d $DEST/fs/bin ]]; then
+    umount $DEST/fs
+ else
+    true
+ fi
+ EOF
+
+ # chmod +x start stop
+
+Let's mount the (still empty) image (as a normal user, not ``root``)::
+
+ $ eval $(su -c /data/media/native/start)
+
+and fill it up::
+
+ # cd /Removable/fs
+ # bzcat2 $wherever/android_gcc_r2a.tar.bz2|tar xvf -
+ # bzcat2 $wherever/android_gcc_supplement.tar.bz2|tar xvf -
+
+(my ``tar`` does not understand ``bzip``-ed archives, so I had to
+decompress them separately)
+
+We need some temporary directories::
+
+ # mkdir -p /Removable/fs/tmp
+ # chown root:root /Removable/fs/tmp
+ # chmod 1777 /Removable/fs/tmp
+
+My shell (the built-in ``/bin/sh``) needs a temporary space under
+``/sqlite_stmt_journals`` for its "here-docs", but my image did not
+mount it, so I had to do it manually::
+
+ # mkdir /sqlite_stmt_journals
+ # mount -t tmpfs none /sqlite_stmt_journals
+
+My installation also lacked a ``true`` binary, which is needed by lots
+of makefiles. I created it this way::
+
+ # cat > /Removable/bin/true <<EOF
+ #!/bin/sh
+ EOF
+ # chmod +x /Removable/bin/true
+
+Building ``perl``
+=================
+
+From here on, we can run as a normal user.
+
+Get a ``perl`` source tarball, and expand it::
+
+ $ cd /Removable/fs/tmp
+ $ tar zxf $perl_tarball
+ $ cd perl-*
+
+We're now ready to build::
+
+ $ BASE=/Removable/fs ./Configure -de -Dprefix=$BASE \
+   -Duserelocatableinc -Dcc=gcc -Dlibpth=$BASE/lib
+
+At the end of the configuration (which should run without errors),
+you'll still not be able to just run ``make``: we have to edit a few
+files.
+
+First, in ``perl.h``, just before ``# endif /* !USE_LOCALE_NUMERIC
+*/``, add this line::
+
+ #define IN_LOCALE_COMPILETIME 0
+
+In the source file for ``Cwd``, we have to tell it to look for the
+``pwd`` binary all over the ``$PATH``, or at least in
+``/system/xbin/pwd``, otherwise it won't find it, and return empty
+strings.
+
+In the source file for ``Errno``, we have to add
+``/Removable/fs/include`` to the list of places where it looks for
+``errno.h``. It should probably ask the compiler for the search list,
+but different compilers do it differently, and it's a mess anyway.
+
+Now, running ``make`` should build ``miniperl``, some core libraries,
+``perl``, some more libraries, and fail as soon as ``XSLoader`` is
+needed. I'm still investigating this.
+
+Future work
+===========
+
+- get to the end of the build
+- package the image and make it available
+- submit patches to reduce the need to muck about with paths and
+  headers
+
+.. _`YAPC::EU 2013`: http://act.yapc.eu/ye2012/
+.. _`Android Scripting Environment`: http://code.google.com/p/android-scripting/
+
diff --git a/src/SW/perl-on-android/du2html.xsl b/src/SW/perl-on-android/du2html.xsl
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+../../../templates/du2html.xsl
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