Cross-compile tools for Ingenic T20

• Main Repository for Low-Level Development
• Setup build environment (Ubuntu / Debian)
  • Install required dependencies
  • Use already prepared Docker image
  • Install some pre-requisites in Docker environment
  • Cross-compile ncurses library
    • 1. Download ncurses
    • 2. Create a build script
    • 3. Execute the build script
  • Download, extract source code for required tools and cross-compile
    • 1. Nano
    • 1. Htop

The Ingenic T20 video SoC is used by quite a lot of Chinese IP cameras. One notable example is Xiaomi Dafang, which is capable of streaming 1080p video in H.264 format and includes pan/tilt motors. This camera is great for hacking, because it runs Linux and installing custom firmware is quite easy: https://github.com/EliasKotlyar/Xiaomi-Dafang-Hacks. Once custom firmware is installed, you can gain SSH access and execute commands on the camera itself, or you can edit the configuration files directly from within the running system. The default editor shipped with the custom firmware is vi, which to be honest is quite a challenge to be used effectively. I personally prefer the nano editor, so following is a log of the steps that I did in order to cross-compile a binary, that can be executed on Ingenic T20 CPUs.

Main Repository for Low-Level Development

Clone this repository using following command:

git clone --recurse-submodules git@github.com:Dafang-Hacks/Main.git

Setup build environment (Ubuntu / Debian)

Install required dependencies

sudo apt install build-essential git gcc-mips-linux-gnu autoconf libtool cmake

Use already prepared Docker image

mkdir ~/dafang
cd ~/dafang
docker run --rm -ti -v $(pwd):/root/ daviey/dafang-cross-compile:latest
git clone --recurse-submodules https://github.com/Dafang-Hacks/Main.git
cd Main

Install some pre-requisites in Docker environment

apt update
apt install nano wget

Cross-compile ncurses library

Shared library ncurses is required by some text-based tools and editors like nano, htop etc. In order to build these tools, first step is cross-compiling the ncurses library:

1. Download ncurses

Download the source archive for ncurses-6.1 into the Main directory:

wget https://ftp.gnu.org/gnu/ncurses/ncurses-6.1.tar.gz
tar xvf ncurses-6.1

2. Create a build script

Create a file with name ‘compile-ncurses.sh’ and the following contents:

#!/usr/bin/env bash
cd ncurses-6.1
TOOLCHAIN=$(pwd)/../toolchain/bin
INSTALLPATH=$(pwd)/..
CROSS_COMPILE=$TOOLCHAIN/mips-linux-gnu-
make clean
export CC=${CROSS_COMPILE}gcc
export CFLAGS="-muclibc -O3"
export CPPFLAGS="-muclibc -O3"
export LDFLAGS="-muclibc -O3"

./autogen.sh
./configure --host=mips-linux-gnu --disable-database --disable-db-install --with-fallbacks=vt100,vt102,vt300,screen,xterm,xterm-256color,tmux-256color,screen-256color --without-manpages --without-normal --without-progs --without-debug --without-test --enable-widec --prefix=${INSTALLPATH}/_install

make
make install
cd ..

Make the script executable with:

chmod +x compile-ncurses.sh

Note the argument values of the –with-fallbacks option of the configure script: these will be the terminal emulators available to nano or other ncurses-based tools (like htop). The default configuration is xterm, but if you like colours support, you can configure another one, e.g.:

TERM=tmux-256color

3. Execute the build script

./compile-ncurses.sh

If the build completes successfully, ncurses headers and libraries files will be available in /root/Main/_install directory.

Download, extract source code for required tools and cross-compile

1. Nano

wget https://www.nano-editor.org/dist/v4/nano-4.3.tar.gz
tar xvf nano-4.3.tar.gz

Create a file with name ‘compile-nano.sh’ and the following contents:

#!/usr/bin/env bash
export INSTALLPATH="$(pwd)/_install"
TOOLCHAIN=$(pwd)/toolchain/bin
CROSS_COMPILE=$TOOLCHAIN/mips-linux-gnu-
export CC=${CROSS_COMPILE}gcc
export CXX=${CROSS_COMPILE}cpp
export LD=${CROSS_COMPILE}ld
export CFLAGS="-muclibc -O2 -static"
export CPPFLAGS="-muclibc -O2 -I${INSTALLPATH}/include -I${INSTALLPATH}/include/ncursesw"
export LDFLAGS="-muclibc -O2 -L${INSTALLPATH}/lib"

cd nano-4.3

./configure --prefix=${INSTALLPATH} --host=mipsel-linux --enable-utf8 --enable-nls --enable-color --enable-multibuffer --enable-nanorc

# Last known good configuration:
#./configure --prefix=/root/Main/_install --host=mipsel-linux --enable-utf8 --disable-nls --enable-color --enable-extra --enable-multibuffer --enable-nanorc

make -j4
make install

Make the script executable with:

chmod +x compile-nano.sh

Execute the build script:

./compile-nano.sh

If everything went fine, the cross-compiled executable will be available here:

/root/Main/_install/bin/nano

1. Htop

wget https://hisham.hm/htop/releases/2.2.0/htop-2.2.0.tar.gz
tar xvf htop-2.2.0.tar.gz

Create a file with name ‘compile-htop.sh’ and the following contents:

#!/usr/bin/env bash
export INSTALLPATH="$(pwd)/_install"
TOOLCHAIN=$(pwd)/toolchain/bin
CROSS_COMPILE=$TOOLCHAIN/mips-linux-gnu-
export CC=${CROSS_COMPILE}gcc
export CXX=${CROSS_COMPILE}cpp
export LD=${CROSS_COMPILE}ld
export CFLAGS="-muclibc -O2 -static"
export CPPFLAGS="-muclibc -O2 -I${INSTALLPATH}/include -I${INSTALLPATH}/include/ncursesw"
export LDFLAGS="-muclibc -O2 -L${INSTALLPATH}/lib"

cd htop-2.2.0

./configure --prefix=${INSTALLPATH} --host=mipsel-linux

make -j4
make install

Make the script executable with:

chmod +x compile-nano.sh

Execute the build script:

./compile-nano.sh

If everything went fine, the cross-compiled executable will be available here:

/root/Main/_install/bin/htop

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