perlandroid

PERLANDROID(1)         Perl Programmers Reference Guide         PERLANDROID(1)

NAME
       perlandroid - Perl under Android

SYNOPSIS
       The first portions of this documents contains instructions to cross-
       compile Perl for Android 2.0 and later, using the binaries provided by
       Google.  The latter portion describes how to build perl native using
       one of the toolchains available on the Play Store.

DESCRIPTION
       This document describes how to set up your host environment when
       attempting to build Perl for Android.

Cross-compilation
       These instructions assume an Unixish build environment on your host
       system; they've been tested on Linux and OS X, and may work on Cygwin
       and MSYS.  While Google also provides an NDK for Windows, these steps
       won't work native there, although it may be possible to cross-compile
       through different means.

       If your host system's architecture is 32 bits, remember to change the
       "x86_64"'s below to "x86"'s.  On a similar vein, the examples below use
       the 4.8 toolchain; if you want to use something older or newer (for
       example, the 4.4.3 toolchain included in the 8th revision of the NDK),
       just change those to the relevant version.

   Get the Android Native Development Kit (NDK)
       You can download the NDK from
       <https://developer.android.com/tools/sdk/ndk/index.html>.  You'll want
       the normal, non-legacy version.

   Determine the architecture you'll be cross-compiling for
       There's three possible options: arm-linux-androideabi for ARM, mipsel-
       linux-android for MIPS, and simply x86 for x86.  As of 2014, most
       Android devices run on ARM, so that is generally a safe bet.

       With those two in hand, you should add

         $ANDROID_NDK/toolchains/$TARGETARCH-4.8/prebuilt/`uname | tr '[A-Z]' '[a-z]'`-x86_64/bin

       to your "PATH", where $ANDROID_NDK is the location where you unpacked
       the NDK, and $TARGETARCH is your target's architecture.

   Set up a standalone toolchain
       This creates a working sysroot that we can feed to Configure later.

           $ export ANDROID_TOOLCHAIN=/tmp/my-toolchain-$TARGETARCH
           $ export SYSROOT=$ANDROID_TOOLCHAIN/sysroot
           $ $ANDROID_NDK/build/tools/make-standalone-toolchain.sh \
                   --platform=android-9 \
                   --install-dir=$ANDROID_TOOLCHAIN \
                   --system=`uname | tr '[A-Z]' '[a-z]'`-x86_64 \
                   --toolchain=$TARGETARCH-4.8

   adb or ssh?
       adb is the Android Debug Bridge.  For our purposes, it's basically a
       way of establishing an ssh connection to an Android device without
       having to install anything on the device itself, as long as the device
       is either on the same local network as the host, or it is connected to
       the host through USB.

       Perl can be cross-compiled using either adb or a normal ssh connection;
       in general, if you can connect your device to the host using a USB
       port, or if you don't feel like installing an sshd app on your device,
       you may want to use adb, although you may be forced to switch to ssh if
       your device is not rooted and you're unlucky -- more on that later.
       Alternatively, if you're cross-compiling to an emulator, you'll have to
       use adb.

       adb

       To use adb, download the Android SDK from
       <https://developer.android.com/sdk/index.html>.  The "SDK Tools Only"
       version should suffice -- if you downloaded the ADT Bundle, you can
       find the sdk under $ADT_BUNDLE/sdk/.

       Add $ANDROID_SDK/platform-tools to your "PATH", which should give you
       access to adb.  You'll now have to find your device's name using "adb
       devices", and later pass that to Configure through
       "-Dtargethost=$DEVICE".

       However, before calling Configure, you need to check if using adb is a
       viable choice in the first place.  Because Android doesn't have a /tmp,
       nor does it allow executables in the sdcard, we need to find somewhere
       in the device for Configure to put some files in, as well as for the
       tests to run in. If your device is rooted, then you're good.  Try
       running these:

           $ export TARGETDIR=/mnt/asec/perl
           $ adb -s $DEVICE shell "echo sh -c '\"mkdir $TARGETDIR\"' | su --"

       Which will create the directory we need, and you can move on to the
       next step.  /mnt/asec is mounted as a tmpfs in Android, but it's only
       accessible to root.

       If your device is not rooted, you may still be in luck. Try running
       this:

           $ export TARGETDIR=/data/local/tmp/perl
           $ adb -s $DEVICE shell "mkdir $TARGETDIR"

       If the command works, you can move to the next step, but beware: You'll
       have to remove the directory from the device once you are done!  Unlike
       /mnt/asec, /data/local/tmp may not get automatically garbage collected
       once you shut off the phone.

       If neither of those work, then you can't use adb to cross-compile to
       your device.  Either try rooting it, or go for the ssh route.

       ssh

       To use ssh, you'll need to install and run a sshd app and set it up
       properly.  There are several paid and free apps that do this rather
       easily, so you should be able to spot one on the store.  Remember that
       Perl requires a passwordless connection, so set up a public key.

       Note that several apps spew crap to stderr every time you connect,
       which can throw off Configure.  You may need to monkeypatch the part of
       Configure that creates "run-ssh" to have it discard stderr.

       Since you're using ssh, you'll have to pass some extra arguments to
       Configure:

         -Dtargetrun=ssh -Dtargethost=$TARGETHOST -Dtargetuser=$TARGETUSER -Dtargetport=$TARGETPORT

   Configure and beyond
       With all of the previous done, you're now ready to call Configure.

       If using adb, a "basic" Configure line will look like this:

         $ ./Configure -des -Dusedevel -Dusecrosscompile -Dtargetrun=adb \
             -Dcc=$TARGETARCH-gcc   \
             -Dsysroot=$SYSROOT     \
             -Dtargetdir=$TARGETDIR \
             -Dtargethost=$DEVICE

       If using ssh, it's not too different -- we just change targetrun to
       ssh, and pass in targetuser and targetport.  It ends up looking like
       this:

         $ ./Configure -des -Dusedevel -Dusecrosscompile -Dtargetrun=ssh \
             -Dcc=$TARGETARCH-gcc        \
             -Dsysroot=$SYSROOT          \
             -Dtargetdir=$TARGETDIR      \
             -Dtargethost="$TARGETHOST"  \
             -Dtargetuser=$TARGETUSER    \
             -Dtargetport=$TARGETPORT

       Now you're ready to run "make" and "make test"!

       As a final word of warning, if you're using adb, "make test" may appear
       to hang; this is because it doesn't output anything until it finishes
       running all tests.  You can check its progress by logging into the
       device, moving to $TARGETDIR, and looking at the file output.stdout.

       Notes

       o   If you are targetting x86 Android, you will have to change
           "$TARGETARCH-gcc" to "i686-linux-android-gcc".

       o   On some older low-end devices -- think early 2.2 era -- some tests,
           particularly t/re/uniprops.t, may crash the phone, causing it to
           turn itself off once, and then back on again.

Native Builds
       While Google doesn't provide a native toolchain for Android, you can
       still get one from the Play Store; for example, there's the CCTools app
       which you can get for free.  Keep in mind that you want a full
       toolchain; some apps tend to default to installing only a barebones
       version without some important utilities, like ar or nm.

       Once you have the toolchain set up properly, the only remaining hurdle
       is actually locating where in the device it was installed in.  For
       example, CCTools installs its toolchain in
       /data/data/com.pdaxrom.cctools/root/cctools.  With the path in hand,
       compiling perl is little more than:

        export SYSROOT=<location of the native toolchain>
        export LD_LIBRARY_PATH="$SYSROOT/lib:`pwd`:`pwd`/lib:`pwd`/lib/auto:$LD_LIBRARY_PATH"
        sh Configure -des -Dsysroot=$SYSROOT -Alibpth="/system/lib /vendor/lib"

AUTHOR
       Brian Fraser <fraserbn@gmail.com>

perl v5.30.0                      2023-11-23                    PERLANDROID(1)