Android Cross-Compilation Build System

Copyright (C) 2025, Christian "kimocoder" Bremvaag
Version: 1.0.0

A unified, modular build system for cross-compiling network security, wireless tools and debug to Android (ARM64/ARM32).

Overview

This build system provides a clean, maintainable architecture for building native Android binaries for both ARM64 and ARM32 architectures. Key features:

Multi-architecture support: Build for ARM64 (aarch64) and ARM32 (armv7a) simultaneously or individually
Automatic dependency resolution: Dependencies are built automatically in the correct order
Version management: Built-in update checking and upgrade functionality
ADB integration: Push built tools directly to Android devices

Core Components

build.sh: Main orchestration script with dependency management, multi-arch support, and comprehensive cleaning
build-env.sh: Environment configuration for NDK paths, compiler toolchain, and global flags
build-{tool}.sh: Individual tool-specific build scripts
tools.conf: Declarative tool manifest defining tools, versions, and dependencies
build.conf: Build configuration (symlink to build-arm64.conf or build-arm.conf)

Quick Start

Prerequisites

Android NDK - Tested with NDK r23+ (API 29+)
Build tools: wget, tar, make, autotools, cmake, gcc
Python tools (for some libraries): meson, ninja

Setup

# Set NDK path
export ANDROID_NDK_HOME=/path/to/android-ndk

# List available tools
./build.sh list

# Build all tools for both architectures
./build.sh build

# Build for specific architecture
./build.sh build --arch arm64    # 64-bit only
./build.sh build --arch arm      # 32-bit only

# Build specific tools (dependencies auto-built)
./build.sh build iw tcpdump

# Check build status
./build.sh status

# Clean all build artifacts
./build.sh clean

# Push to Android device
./build.sh push iw tcpdump

Architecture

Directory Structure

.
├── build.sh                   # Main orchestrator
├── build-env.sh              # Environment configuration (in scripts/)
├── scripts/                  # Tool-specific build scripts
│   ├── build-env.sh          # Environment configuration
│   ├── build-libnl3.sh
│   ├── build-libpcap.sh
│   ├── build-openssl.sh
│   ├── build-aircrack-ng.sh
│   ├── build-reaver.sh
│   ├── build-mdk4.sh
│   ├── verify-artifacts.sh   # Artifact verification
│   ├── verify-tool-scripts.sh # Tool script validation
│   ├── fix-tls-alignment.py  # TLS alignment fix for ARM64
│   └── ... (all tool scripts)
├── tools.conf                # Tool manifest
├── build.conf                # Build configuration
├── src/                      # Source code
├── build/                    # Build artifacts (temporary)
├── out/                      # Final output
│   └── aarch64-linux-android/
│       ├── libnl3/
│       ├── libpcap/
│       ├── openssl/
│       ├── aircrack-ng/
│       ├── reaver/
│       ├── mdk4/
│       ├── hcxdumptool/
│       ├── hcxtools/
│       ├── nmap/
│       ├── iw/
│       └── ... (all tools)
├── logs/                     # Build logs
└── patches/                  # Patch files

Dependency Graph

Core Libraries (no dependencies):
  libnl3, libpcap, libcap, libnet, libmnl, openssl, ifaddrs, radiotap
  zlib, c-ares, libffi, pcre2, libintl-lite, libxml2, libgpg-error, libgcrypt, glib2

Wireless Tools:
  libnl3 ──────┬─→ mdk4 (also needs libpcap)
               └─→ aircrack-ng (also needs libpcap, libnet, openssl)
  
  libpcap ─────┬─→ tcpdump
               ├─→ tshark (also needs glib2, zlib, c-ares, libgcrypt, pcre2, libxml2, libintl-lite, libnl3)
               ├─→ aircrack-ng (also needs libnet, openssl, libnl3)
               ├─→ reaver (also needs libnl3)
               ├─→ hcxdumptool (also needs openssl, ifaddrs)
               └─→ hcxtools (also needs openssl)
  
  openssl ─────┬─→ aircrack-ng
               ├─→ hcxdumptool
               └─→ hcxtools

Network Tools:
  libnl3 ──────→ iw
  libmnl ──────┬─→ iproute2
               └─→ ethtool
  nmap, rfkill, net-tools (no dependencies)

Utilities:
  busybox, nano, strace, curl, pixiewps, macchanger, qca-monitor, wireless-tools (no dependencies)

Usage

Build Commands

# Build all tools in dependency order
./build.sh build

# Build specific tools (with dependencies)
./build.sh build iw libpcap

# Build for specific architecture
./build.sh build --arch arm64           # 64-bit ARM only
./build.sh build --arch arm             # 32-bit ARM only
./build.sh build --arch both            # Both architectures (default)

# Clean all artifacts (removes build dirs, tarballs, .o files)
./build.sh clean

# Clean specific tool
./build.sh clean iw

# Rebuild (clean + build)
./build.sh rebuild

# List available tools
./build.sh list

# Show build status
./build.sh status

# Check for updates
./build.sh update

# Upgrade to latest version
./build.sh upgrade

# Push tools to Android device via ADB
./build.sh push iw tcpdump

# Show help
./build.sh help

Verbose Output

# Enable verbose logging
VERBOSE=1 ./build.sh build

# Or use flag
./build.sh -v build

Parallel Jobs

# Control number of parallel build jobs
PARALLEL_JOBS=4 ./build.sh build

Source Management

Local Sources Priority

All build scripts prioritize local sources in src/ directory before downloading:

Check existing build - If already extracted in scripts/build/TOOL/src/, use it
Check local source - If src/TOOL/ exists, copy it to build directory
Download fallback - Only download if local source not found

This ensures:

✅ Your patches and modifications are preserved
✅ No bandwidth wasted on re-downloading
✅ Sources can be committed to git
✅ Offline building when sources are present

Populating Local Sources

After first build, copy sources to src/ for future use:

# Build once (downloads sources)
./build.sh build curl

# Copy to local source directory
cp -r scripts/build/curl/src/curl-src src/curl

# Clean and rebuild (now uses local source)
./build.sh clean curl
./build.sh build curl  # Uses src/curl

Configuration

tools.conf

Defines all available tools and their properties:

# Format: TOOL_NAME|VERSION|DEPENDENCIES|CONFIGURE_OPTS|PATCHES|BUILD_TYPE|IS_LIBRARY
libnl3|3.7.0||--disable-cli --disable-pthreads|libnl-android-in_addr.patch|autotools|yes
iw|5.16|libnl3|--disable-cli|iw-android.patch|make|no

build.conf

Symlink to architecture-specific configuration:

build-arm64.conf - ARM64 (aarch64-linux-android)
build-arm.conf - ARM32 (armv7a-linux-androideabi)

Customizes build behavior:

# Global settings
PARALLEL_JOBS=$(nproc)
VERBOSE=0
LOG_DIR=logs

# Target configuration
TARGET_ARCH=arm64
TARGET_TRIPLE=aarch64-linux-android
API_LEVEL=29

# Per-tool overrides
TOOL_CFLAGS_libnl3="-O2 -fPIC -D_GNU_SOURCE"

Tool Build Scripts

Each tool has a dedicated build script following this pattern:

#!/bin/bash
set -euo pipefail

# Source environment
source ./build-env.sh

# Tool configuration
TOOL_NAME="example"
TOOL_DEPS=("dependency1" "dependency2")

# Verify dependencies
for dep in "${TOOL_DEPS[@]}"; do
  if [ ! -f "$PREFIX/$dep/.built" ]; then
    echo "ERROR: Dependency $dep not built"
    exit 1
  fi
done

# Download, configure, build, install
# ... build steps ...

# Create marker file
touch "$PREFIX/$TOOL_NAME/.built"

Key Features

Dependency verification: Checks that all dependencies are built before building
Logging: All output logged to timestamped files in logs/
Artifact verification: Verifies output files exist and are valid
Error handling: Exits with non-zero status on failure
Environment isolation: All configuration from build-env.sh

Verification

Verify Artifacts

# Verify built artifacts
./scripts/verify-artifacts.sh libnl3 libpcap iw

Checks:

Output directories exist
Libraries are valid ELF binaries
Headers are readable
Executables are for correct architecture

Verify Tool Scripts

# Verify tool scripts follow conventions
./scripts/verify-tool-scripts.sh

Checks:

Scripts source build-env.sh
No hardcoded NDK paths
Uses environment variables for toolchain

Output Structure

Each tool installs to: out/aarch64-linux-android/{tool_name}/

out/aarch64-linux-android/libnl3/
├── lib/
│   ├── libnl-3.a
│   ├── libnl-3.so
│   ├── libnl-genl-3.a
│   └── libnl-genl-3.so
├── include/
│   └── libnl3/
│       ├── netlink/
│       └── netlink/genl/
├── bin/
└── .built (marker file)

Extensibility

Adding a new tool is simple:

Add source to src/TOOL/ directory (or let it download)

Create scripts/build-{tool}.sh following the template:

#!/bin/bash
set -euo pipefail
source "$(dirname "${BASH_SOURCE[0]}")/build-env.sh"

TOOL_NAME="mytool"
TOOL_VERSION="1.0"
TOOL_DEPS=("dependency1")

# Check for local source first
if [ -d "$SCRIPT_DIR/../src/mytool" ] && [ ! -d "$SRC_DIR/mytool-src" ]; then
  log "Using local source..."
  cp -r "$SCRIPT_DIR/../src/mytool" "$SRC_DIR/mytool-src"
elif [ ! -d "$SRC_DIR/mytool-src" ]; then
  # Download logic here
fi

# Build, install, create .built marker

Add entry to tools.conf:

mytool|1.0|dependency1|--enable-static|mytool.patch|autotools|no

Run ./build.sh build mytool

The main build script automatically discovers and integrates new tools.

ARM64 TLS Alignment

Android Bionic on ARM64 requires TLS (Thread-Local Storage) segments to be aligned to 64 bytes. Some tools built with older toolchains may have 8-byte alignment, causing this error:

error: executable's TLS segment is underaligned: alignment is 8, needs to be at least 64

The build system automatically fixes this for ARM64 binaries using scripts/fix-tls-alignment.py, which patches the ELF headers to set proper alignment. This is applied automatically during the build process for affected tools like:

iproute2 (ip, tc, ss, etc.)
net-tools (ifconfig, netstat, route, arp, etc.)
ethtool
wireless-tools (iwconfig, iwlist, iwspy, etc.)

No manual intervention is required - the fix is integrated into the build scripts.

Troubleshooting

NDK Not Found

export ANDROID_NDK_HOME=/path/to/android-ndk
./build.sh build

Build Fails

Check the log file:

tail -f logs/build-{tool}-*.log

Dependency Issues

Verify dependency order:

./build.sh list

Rebuild dependencies:

./build.sh rebuild libnl3

TLS Alignment Errors on ARM64

If you see TLS alignment errors, the automatic fix may have failed. Manually apply it:

python3 scripts/fix-tls-alignment.py path/to/binary

Environment Variables

Variable	Default	Description
ANDROID_NDK_HOME	(required)	Path to Android NDK
TARGET_TRIPLE	aarch64-linux-android	Target architecture triple
API_LEVEL	29	Android API level
PARALLEL_JOBS	$(nproc)	Number of parallel build jobs
VERBOSE	0	Enable verbose output (0 or 1)
KEEP_SOURCES	1	Keep downloaded sources after build
KEEP_BUILD_DIRS	0	Keep build directories after build
LOG_DIR	logs	Directory for build logs

Build Logs

All build output is logged to logs/build-{tool}-{timestamp}.log

View recent logs:

ls -lt logs/ | head -10
tail -f logs/build-libnl3-*.log

Supported Tools

Core Libraries

Tool	Version	Dependencies	Type
libnl3	3.7.0	-	autotools
libpcap	1.10.1	-	autotools
libcap	2.66	-	autotools
libnet	1.2.0	-	autotools
libmnl	1.0.5	-	autotools
openssl	3.x	-	make
ifaddrs	master	-	make
radiotap	master	-	make

Wireless Security Tools

Tool	Version	Dependencies	Type	Description
aircrack-ng	1.7	libnet, libpcap, openssl	autotools	WiFi security suite (9 tools)
reaver	1.6.6	libpcap, libnl3	autotools	WPS PIN cracking + wash scanner
mdk4	master	libpcap, libnl3	make	WiFi testing and attack tool
hcxdumptool	7.0.1	libpcap, openssl, ifaddrs	make	WiFi packet capture for hashcat
hcxtools	7.0.1	libpcap, openssl	make	Hash conversion tools (6 tools)
pixiewps	1.4.2	-	autotools	WPS Pixie Dust attack
macchanger	1.7.0	-	autotools	MAC address spoofing
wireless-tools	30.pre9	-	make	Classic wireless tools (iwconfig, iwlist, iwspy, etc.)
qca-monitor	master	-	make	Qualcomm monitor mode enabler

Network Tools

Tool	Version	Dependencies	Type	Description
nmap	7.93	-	autotools	Network scanner + ncat + nping
tcpdump	4.99.1	libpcap	autotools	Network packet analyzer
tshark	4.0.0	libpcap, glib2, zlib, c-ares, libgcrypt, pcre2, libxml2, libintl-lite, libnl3	cmake	Wireshark terminal-based packet analyzer
iw	5.16	libnl3	make	Wireless configuration utility
rfkill	1.0	-	make	Tool to enable/disable wireless devices
iproute2	6.1.0	libmnl	make	Advanced routing and network configuration (ip, tc, ss, etc.)
net-tools	2.10	-	make	Classic network tools (ifconfig, netstat, route, arp, etc.)
ethtool	6.15	libmnl	autotools	Ethernet interface configuration and tuning

Utilities

Tool	Version	Dependencies	Type	Description
busybox	1.38.0	-	make	Multi-call binary with Unix utilities
nano	8.7	ncurses	autotools	Text editor
strace	6.12	-	autotools	System call tracer for debugging
curl	8.0.0	-	autotools	URL transfer tool

Total: 30 tools/libraries successfully building for Android ARM64 (aarch64), API 21+

Development

Adding Patches

Place patch files in patches/ directory

Reference in tools.conf:

tool_name|version|deps|opts|patch-file.patch|type|is_library

Patches are applied after source preparation (local or downloaded)

Customizing Flags

Edit architecture-specific config files:

# build-arm64.conf or build-arm.conf
TOOL_CFLAGS_mytool="-O3 -march=armv8-a"
TOOL_LDFLAGS_mytool="-Wl,-rpath,\$ORIGIN"

Version Management

# Check for updates
./build.sh update

# Upgrade to latest version
./build.sh upgrade

The system pulls from the git repository and updates the version file.

Files Excluded from Git

The .gitignore file excludes:

Build artifacts (build/, out/, logs/)
Downloaded tarballs (*.tar.gz, *.tar.xz, etc.)
Object files and libraries (*.o, *.a, *.so)
CMake and autotools artifacts
Test directories
Backup files

This keeps the repository clean and focused on source code and build scripts.

Contributing

When contributing:

Place modified sources in src/TOOL/ directory
Update build scripts to check local sources first
Document any new dependencies in tools.conf
Test on both ARM64 and ARM32 architectures
Update README.md with new features

License

This build system is provided as-is for cross-compiling Android tools.

Name		Name	Last commit message	Last commit date
Latest commit History 44 Commits
.github		.github
patches		patches
scripts		scripts
src		src
.dockerignore		.dockerignore
.gitignore		.gitignore
Dockerfile		Dockerfile
LICENSE		LICENSE
README.md		README.md
build-arm.conf		build-arm.conf
build-arm64.conf		build-arm64.conf
build.conf		build.conf
build.sh		build.sh
docker-build.sh		docker-build.sh
docker-compose.yml		docker-compose.yml
tools.conf		tools.conf
version		version

License

kimocoder/kali-nethunter-tools

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Android Cross-Compilation Build System

Overview

Core Components

Quick Start

Prerequisites

Setup

Architecture

Directory Structure

Dependency Graph

Usage

Build Commands

Verbose Output

Parallel Jobs

Source Management

Local Sources Priority

Populating Local Sources

Configuration

tools.conf

build.conf

Tool Build Scripts

Key Features

Verification

Verify Artifacts

Verify Tool Scripts

Output Structure

Extensibility

ARM64 TLS Alignment

Troubleshooting

NDK Not Found

Build Fails

Dependency Issues

TLS Alignment Errors on ARM64

Environment Variables

Build Logs

Supported Tools

Core Libraries

Wireless Security Tools

Network Tools

Utilities

Development

Adding Patches

Customizing Flags

Version Management

Files Excluded from Git

Contributing

License

References

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