System Services

SerenityOS uses a modern service-oriented architecture with a robust Inter-Process Communication (IPC) system. Each service runs as a separate process, providing isolation and stability.

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Core System Services

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WindowServer

The display server responsible for managing all graphical output and user interaction.

Key Responsibilities

• Window management and composition
• Input event distribution (mouse, keyboard, touch)
• Display output and rendering coordination
• Desktop environment and taskbar integration
• Window decorations and themes
• Cursor management

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LoginServer

Manages user authentication and session initialization. Features:

• User login and authentication
• Session creation and management
• Graphical login interface
• User switching capabilities
• Integration with the security subsystem

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SystemServer

The init system responsible for starting and managing system services.

• Service lifecycle management
• Dependency resolution
• Service socket management
• Automatic service respawning
• System startup orchestration

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Audio & Multimedia Services

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AudioServer

Capabilities:

• Multi-client audio mixing
• Sample rate conversion
• Volume control and normalization
• Multiple audio format support (WAV, MP3, FLAC)
• Per-application audio routing
• Low-latency audio processing

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ImageDecoder

Sandboxed image decoding service for security and stability.

Supported Formats

• PNG (Portable Network Graphics)
• JPEG (Joint Photographic Experts Group)
• GIF (Graphics Interchange Format)
• BMP (Bitmap)
• ICO (Icon)
• PBM/PGM/PPM (Portable Anymap)
• QOI (Quite OK Image)
• TGA (Targa)
• And more

Security Features:

• Each decode operation runs in a fresh process
• Strong sandboxing with pledge() and unveil()
• Memory-safe decoding implementations
• Automatic cleanup on completion

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Network Services

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RequestServer

Handles all outgoing network requests for web content and other applications. Supported Protocols:

• HTTP/1.1
• HTTPS (TLS 1.2, 1.3)
• Gemini
• File protocol

Features:

• Connection pooling and reuse
• Cookie management
• Proxy support
• Content negotiation
• Download management

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LookupServer

System-wide DNS resolver with caching capabilities.

• DNS query handling (A, AAAA, CNAME, MX, etc.)
• Local hosts file resolution
• Query caching for performance
• Multiple nameserver support
• DNSSEC validation (in development)

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TelnetServer

Provides telnet server functionality for remote terminal access.

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Web Services

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WebContent

Sandboxed web rendering process that powers the Browser application.

Architecture Details

Each browser tab runs in its own WebContent process for isolation:

• HTML/CSS rendering engine (LibWeb)
• JavaScript execution (LibJS)
• WebAssembly support
• DOM manipulation
• Canvas and SVG rendering

Communicates only through:

• RequestServer for network access
• ImageDecoder for image processing
• IPC with the Browser process

Security:

• Per-tab process isolation
• Unprivileged user execution
• Strict pledge() and unveil() restrictions
• No direct network or filesystem access

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WebWorker

Handles Web Worker threads for background JavaScript execution in web pages.

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WebDriver

Implements the WebDriver protocol for automated browser testing.

• Browser automation support
• Testing framework integration
• Selenium-compatible API
• Automated UI testing capabilities

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Storage & Data Services

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SQLServer

Embedded SQL database service for applications requiring structured data storage. Features:

• SQL query execution
• Transaction support
• Multi-client access
• Data persistence
• Query optimization

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FileSystemAccessServer

Mediates file system access with security controls.

• File picker integration
• Permission management
• Sandboxed file access
• Secure file operations
• User consent workflows

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ConfigServer

Centralized configuration management service.

• System-wide settings storage
• Per-application configuration
• Configuration change notifications
• Atomic configuration updates
• Default value management

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Desktop Services

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Taskbar

Provides the system taskbar and task switching functionality.

• Application launcher
• Running application indicators
• System tray integration
• Clock display
• Quick settings access
• Workspace switching

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NotificationServer

System notification management and display.

• Desktop notifications
• Notification queuing
• Priority management
• Action buttons support
• Do Not Disturb mode
• Notification history

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Clipboard

System-wide clipboard management for cut, copy, and paste operations.

• Text and image clipboard support
• Multiple MIME type handling
• Clipboard history (optional)
• Inter-application data transfer

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Utility Services

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CrashDaemon

Automatically handles application crashes.

• Crash detection and logging
• Core dump generation
• Stack trace collection
• Crash reporter integration
• Debugging information preservation

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LaunchServer

Application launcher and file association manager.

• File type associations
• Default application handling
• URL protocol handlers
• Application spawning
• Desktop entry management

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ChessEngine

Dedicated chess engine service for the Chess application.

• Chess move calculation
• AI opponent logic
• Position evaluation
• Game state management

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SpiceAgent

Integration with QEMU/SPICE for enhanced virtualization support.

• Clipboard sharing with host
• Display resolution synchronization
• File transfer capabilities
• Enhanced input handling

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DeviceMapper

Manages device node creation and device events.

• Dynamic device node creation
• Device hotplug handling
• Permission management
• Device enumeration

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NetworkServer

Network interface and routing management.

• Network interface configuration
• Route table management
• Network status monitoring
• Connection state tracking

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KeyboardPreferenceLoader

Loads and applies keyboard preferences at system startup.

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FileOperation

Handles long-running file operations in the background.

• Copy/move operations
• Progress tracking
• Cancellation support
• Error handling

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EchoServer

Simple echo server for testing and development purposes.

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Service Communication

All services are designed with the following principles:

• Isolation: Each service runs in its own process
• Sandboxing: Services use pledge() and unveil() for security
• Privilege Separation: Services run with minimal required privileges
• Failure Isolation: Service crashes don’t affect other services
• Clean IPC: Type-safe communication through generated IPC interfaces

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Service Management

Services are managed by SystemServer, which reads configuration from service definition files. Services can be:

• Started automatically at boot
• Started on-demand via socket activation
• Configured with dependencies
• Automatically restarted on failure
• Monitored for health and performance