> ## Documentation Index
> Fetch the complete documentation index at: https://openclawonandroid.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Architecture

> How OCA bridges Android's Bionic libc and the glibc-based Node.js ecosystem.

## The Core Problem

Android uses **Bionic libc** — a stripped-down libc optimized for mobile. Most Linux binaries (including the official Node.js release) are compiled against **GNU glibc**, which is incompatible with Bionic.

Standard workarounds:

* **Proot/chroot**: Runs a full Linux distro, heavy overhead
* **Termux Node.js build**: Compiled against Bionic, but npm native modules often fail
* **OCA's approach**: Use `glibc-runner` to inject the real glibc linker at exec-time — no VM, no overhead

***

## Layer Diagram

```
┌─────────────────────────────────────────────────────┐
│                  Android (Bionic libc)               │
├─────────────────────────────────────────────────────┤
│            Termux ($PREFIX = /data/data/             │
│                 com.termux/files/usr/)               │
├─────────────────────────────────────────────────────┤
│  glibc-runner (pkg: glibc-runner)                    │
│  └─ $PREFIX/glibc/lib/ld-linux-aarch64.so.1         │
│     └─ bridges: glibc ↔ Bionic kernel calls         │
├─────────────────────────────────────────────────────┤
│  Node.js v24 linux-arm64 (official tarball)          │
│  └─ ~/.oca/node/bin/node  (grun wrapper)             │
│     └─ ~/.oca/node/bin/node.real  (actual binary)    │
├─────────────────────────────────────────────────────┤
│  OpenClaw Gateway (npm package)                      │
│  ├─ clawdhub  (skill manager)                        │
│  ├─ AI CLIs   (Qwen, Claude, Gemini, Codex)         │
│  └─ oca CLI   (management wrapper)                   │
└─────────────────────────────────────────────────────┘
```

***

## Key Components

### glibc-runner (`grun`)

The `glibc-runner` Termux package provides a launcher that executes binaries with the real glibc dynamic linker. The OCA `node` wrapper calls:

```bash theme={null}
exec "$PREFIX/bin/grun" "$(dirname "$0")/node.real" "$@"
```

### glibc-compat.js

A Node.js preload script that polyfills Android-specific limitations:

* `os.cpus()` — Android 12+ restricts CPU topology access
* `os.networkInterfaces()` — may panic on restricted kernels

### DNS Fix

Android 12+ removed `/etc/resolv.conf`. OCA writes `$PREFIX/glibc/etc/resolv.conf`:

```
nameserver 8.8.8.8
nameserver 1.1.1.1
```

***

## File Structure

```
~/.oca/
├── node/
│   └── bin/
│       ├── node          ← grun wrapper script
│       ├── node.real     ← actual Node.js binary
│       ├── npm
│       └── npx
├── patches/
│   ├── glibc-compat.js   ← os.cpus / networkInterfaces polyfill
│   └── argon2-stub.js    ← argon2 native module stub
├── platforms/
│   └── openclaw/
└── .platform             ← "openclaw" marker
```

CLI tools:

```
$PREFIX/bin/oca          ← OCA management CLI
$PREFIX/bin/ocaupdate    ← Update shortcut
```