Compilation on Android

Radare2 can be cross-compiled for other architectures/systems as well, like Android.

Prerequisites

• Python 3

• Meson

• Ninja

• Git

• Android NDK

Step-by-step

Download and extract the Android NDK

Download the Android NDK from the official site and extract it somewhere on your system (e.g. /tmp/android-ndk)

Make

Specify NDK base path

$ echo NDK=/tmp/android-ndk  > ~/.r2androidrc

Compile + create tar.gz + push it to connected android device

./sys/android-build.sh arm64-static

You can build for different architectures by changing the argument to ./sys/android-build.sh. Run the script without any argument to see the accepted values.

Meson

Create a cross-file for meson

Meson needs a configuration file that describes the cross compilation environment (e.g. meson-android.ini). You can adjust it as necessary, but something like the following should be a good starting point:

[binaries]
c       = '/tmp/android-ndk/toolchains/llvm/prebuilt/linux-x86_64/bin/aarch64-linux-android28-clang'
cpp     = '/tmp/android-ndk/toolchains/llvm/prebuilt/linux-x86_64/bin/aarch64-linux-android28-clang++'
ar      = '/tmp/android-ndk/toolchains/llvm/prebuilt/linux-x86_64/bin/aarch64-linux-android-ar'
as      = '/tmp/android-ndk/toolchains/llvm/prebuilt/linux-x86_64/bin/aarch64-linux-android-as'
ranlib  = '/tmp/android-ndk/toolchains/llvm/prebuilt/linux-x86_64/bin/aarch64-linux-android-ranlib'
ld      = '/tmp/android-ndk/toolchains/llvm/prebuilt/linux-x86_64/bin/aarch64-linux-android-ld'
strip   = '/tmp/android-ndk/toolchains/llvm/prebuilt/linux-x86_64/bin/aarch64-linux-android-strip'
pkgconfig = 'false'

[properties]
sys_root = '/tmp/android-ndk/sysroot'

[host_machine]
system = 'android'
cpu_family = 'arm'
cpu = 'aarch64'
endian = 'little'

Compile with meson + ninja

Now setup the build directory with meson as usual:

$ CFLAGS="-static" LDFLAGS="-static" meson --default-library static --prefix=/tmp/android-dir -Dblob=true build --cross-file ./meson-android.ini

A bit of explanation about all the options:

• CFLAGS="-static", LDFLAGS="-static", --default-library static: this

  ensure that libraries and binaries are statically compiled, so you do not need

  to properly set LD_* environment variables in your Android environment to make

  it find the right libraries. Binaries have everything they need inside.

• -Dblob=true: it tells meson to compile just one binary with all the needed

  code for running radare2, rabin2, rasm2, etc. and creates symbolic links to

  those names. This avoids creating many statically compiled large binaries and

  just create one that provides all features. You will still have rabin2,

  rasm2, rax2, etc. but they are just symlinks to radare2.

• --cross-file ./meson-android.ini: it describes how to compile radare2 for Android

Then compile and install the project:

$ ninja -C build
$ ninja -C build install

Move files to your android device and enjoy

At this point you can copy the generated files in /tmp/android-dir to your Android device and running radare2 from it. For example:

$ cd /tmp && tar -cvf radare2-android.tar.gz android-dir
$ adb push radare2-android.tar.gz /data/local/tmp
$ adb shell
DEVICE:/ $ cd /data/local/tmp
DEVICE:/data/local/tmp $ tar xvf radare2-android.tar.gz
DEVICE:/data/local/tmp $ ./android-dir/bin/radare2
Usage: r2 [-ACdfLMnNqStuvwzX] [-P patch] [-p prj] [-a arch] [-b bits] [-i file]
          [-s addr] [-B baddr] [-m maddr] [-c cmd] [-e k=v] file|pid|-|--|=