Cross Compile RSync ARM

Mon, 15 Aug 2016 15:44:05 -0400

As always, feel free to ask. // Sherlock

Motivation

I got some issues about compile seafile to android, so instead of doing so, I start to figure out some other synchronize workflow. Rsync is one of the most mature synchronization solution. So I made the decision on planting rsync to android.

Pre-work

Rsync is a sync program with delta sync feature and based on SSH connection. So all we need to do is SSH support and cross compile tool-chain. Similar to what I mentioned in previews blog, Android NDK and environment export need to be done before compilation. To enable normally use of compiled program, we need to make android support SSH. My solution is just install SSHDroid from Google Play Store.

Cross-Compile Rsync

Running following script to build rsync. It will generate a executable file named rsync in the root directory.

$ ./configure --build=${BUILD_SYS} --host=${TOOLCHAIN}
$ make

Push RSync to Android.

After installing SSHDroid, we can now push our arm-version-rsync to target machine.

$ adb push rsync /data/local/tmp
$ adb shell

$ cd /data/data/berserker.android.apps.sshdroid/dropbear
$ mv ../../../local/tmp/rsync .

Run Rsync with argument

Now we can easily use rsync in android shell. Similar to what we use on PC.

$ ./rsync -e "./ssh" {target-data} {target-location}:{target-directory}

References

Build Rsync for Android

Cross Compile Seafile to ARM

Sat, 30 Jul 2016 14:02:34 -0400

Motivation

This project is working for delta sync from mobile to server. Currently, there’s no mobile program/solution has supporting to delta sync(Include Dropbox/ Goggle Drive). But the truth is that almost every pc version sync program can work as delta sync properly or not. So in this article, I’ll provide a workbench for cross compilation and evaluation. And finally come up with a reason of how to port better incremental synchronize solution on mobile platform.

Pre-work

Basically, I used the native android compilation tool-chains, Android NDK, as working tools. Due to my working situation, I use a Nvidia Shield Tablet as target device. As Zengwen said in his blog, newest updated NDK might has some issue which can influence compilation progress. So you can find other version of NDK once you have some problems. Based on what Zengwen’s blog mentioned, we can write following useful system environment and export in terminal.

Prerequisites

$ sudo apt-get install build-essential
$ sudo apt-get install pkg-config automake autoconf libtool

Link with standalone tool-chains

In order to build standalone tool-chains, we need first to export following system environment. After doing that, we can use following command to build a standalone tool-chains from downloaded NDK.

$ ${NDK}/build/tools/make-standalone-toolchain.sh \
    --toolchain=arm-linux-androideabi-4.9 \
    --stl=gnustl \
    --arch=arm \
    --ndk-dir=/home/moslab/Android/android-ndk-r12b \
    --package-dir=/home/moslab/Android \
    --install-dir=/home/moslab/Android/android-ndk-toolchain \
    --platform=android-22

Original System Environment Configuration

[TODO]-> I will fix this part later.

# Android NDK sources and standalone toolchain is put here
export DEV=~/Android/

# All the built binaries, libs and their header will be installed here
export PREFIX=/opt/android

# Don't mix up .pc files from your host and build target
export PKG_CONFIG_PATH=${PREFIX}/lib/pkgconfig

# GCC for Android version to use
# 4.9 is the only available version since NDK r11!
export GCC_VER=4.9

# The building system we are using (Linux x86_64)
export BUILD_SYS=x86_64-linux-gnu

# Set Android target API level
export ANDROID_API=22

# Set Android target arch
export ANDROID_ARCH=arm

# Set Android target name, according to Table 2 in
# https://developer.android.com/ndk/guides/standalone_toolchain.html
export ANDROID_TARGET=armv7-none-linux-androideabi

# The cross-compile toolchain we use
export TOOLCHAIN=arm-linux-androideabi

# This is a symlink pointing to the real Android NDK r12b
export NDK=${DEV}/android-ndk

# The path of standalone NDK toolchain
# Refer to https://developer.android.com/ndk/guides/standalone_toolchain.html
export NDK_TOOLCHAIN=${DEV}/android-ndk-toolchain

# this one is the absolute, prebuilt path
export SYSROOT=${NDK}/platforms/android-${ANDROID_API}/arch-${ANDROID_ARCH}

# this one is the absolute, prebuilt path
export CROSS_PREFIX=${NDK}/toolchains/${TOOLCHAIN}-${GCC_VER}/prebuilt/linux-x86_64/bin/${TOOLCHAIN}

# Non-exhaustive lists of compiler + binutils
export AR=${CROSS_PREFIX}-ar
export AS=${CROSS_PREFIX}-as
export LD=${CROSS_PREFIX}-ld
export NM=${CROSS_PREFIX}-nm
export CC=${CROSS_PREFIX}-gcc
export CXX=${CROSS_PREFIX}-g++
export CPP=${CROSS_PREFIX}-cpp
export CXXCPP=${CROSS_PREFIX}-cpp
export STRIP=${CROSS_PREFIX}-strip
export RANLIB=${CROSS_PREFIX}-ranlib
export STRINGS=${CROSS_PREFIX}-strings

# Set build flags
# Refer to https://developer.android.com/ndk/guides/standalone_toolchain.html
export PATH=$PATH:${PREFIX}/bin:${PREFIX}/lib
export CFLAGS="--sysroot=${SYSROOT} -I${SYSROOT}/usr/include -I${PREFIX}/include -fPIE -DANDROID -Wno-multichar"
export CXXFLAGS=${CFLAGS}
export CPPFLAGS="--sysroot=${SYSROOT} -I${SYSROOT}/usr/include -I${NDK_TOOLCHAIN}/include/c++/ -DANDROID -DNO_XMALLOC -mandroid"
export LIBS="-lc -lstdc++ -ld"
export LDFLAGS="-Wl,-rpath-link=-I${SYSROOT}/usr/lib -L${SYSROOT}/usr/lib -L${PREFIX}/lib -L${NDK_TOOLCHAIN}/lib"

Compile Process

To compile seafile, we should compile ccnet and libsearpc first. As for these two projects, they all have their own dependencies, so we must follow some order to run the compilation.

Cross Compile on Mil años de solitario

Cross Compile RSync ARM

Motivation

Pre-work

Cross-Compile Rsync

Push RSync to Android.

Run Rsync with argument

References

Cross Compile Seafile to ARM

Motivation

Pre-work

Prerequisites

Link with standalone tool-chains

Original System Environment Configuration

Compile Process

libsearpc

glib

libiconv

libffi

gettext

libjasson

ccnet

libuuid

seafile

Preferences