🚨 Emergency Management System

A multithreaded emergency dispatching system written in C (C11), implementing message queues, concurrency control, and digital-twin responders.

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📌 Overview

This project simulates a real-time emergency management platform where emergencies are received, queued, prioritized, and assigned to available responders.

The system is composed of multiple modules (dispatcher, queue, responders, logger...) and relies on:

• C11 threads (thrd_t)
• POSIX message queues
• Mutexes (mtx_t)
• Priority-based emergency scheduling
• Separate threads for responders returning from missions

The goal is to reproduce realistic emergency handling: reception, prioritization, assignment, mission duration, and responder return.

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🧩 Features

✔ Emergency Reception

Incoming emergencies are sent through a POSIX message queue and handled asynchronously by the system.

✔ Priority Queue

Emergencies are stored in a priority queue, ordered by:

1. Severity
2. Timestamp (FIFO within same severity)

✔ Dispatcher Module

A dedicated dispatcher thread:

• Monitors the priority queue
• Assigns emergencies to available responders (digital twins)
• Spawns mission threads to simulate real-world timing
• Logs every relevant event

✔ Responders (Digital Twins)

Each responder:

• Can handle one emergency at a time
• Has a dedicated thread simulating mission duration
• Returns asynchronously, notifying the dispatcher of availability

✔ Logging System

Every event (enqueue, dequeue, assignment, completion…) is recorded through a centralized logger.

✔ Clean Resource Management

• Proper initialization and destruction of mutexes
• Graceful shutdown
• dispatcher_destroy() correctly releases resources

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🏛 Architecture

               ╔═══════════════════════╗
               ║      Emergency        ║
               ║       Sender          ║
               ╚═══════════════════════╝
                          │
                          ▼
            ╔══════════════════════════════╗
            ║     POSIX Message Queue      ║
            ╚══════════════════════════════╝
                          │
                          ▼
            ╔══════════════════════════════╗
            ║        Emergency Receiver    ║
            ╚══════════════════════════════╝
                          │
                          ▼
            ╔══════════════════════════════╗
            ║        Priority Queue        ║
            ║ (protected by a mutex lock)  ║
            ╚══════════════════════════════╝
                          │
                          ▼
            ╔══════════════════════════════╗
            ║          Dispatcher          ║
            ║    (thread + queue mutex)    ║
            ╚══════════════════════════════╝
                          │
          assigns emergencies to available units
                          │
                          ▼
╔════════════════════╗          ╔════════════════════╗
║    Responder #1    ║   ...    ║    Responder #N    ║
║ (thread: mission)  ║          ║ (thread: mission)  ║
╚════════════════════╝          ╚════════════════════╝

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🗂 Project Structure

/src

├── dispatcher.c / dispatcher.h

├── emergency.c / emergency.h

├── queue.c / queue.h

├── responder.c / responder.h

├── logger.c / logger.h

├── utils.c / utils.h

├── main.c

• dispatcher/ → core scheduling logic, mutex-protected queue, responder assignment
• queue/ → priority queue implementation
• responder/ → thread routines for emergency missions
• logger/ → thread-safe logging
• main.c → initialization, configuration, startup and shutdown

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⚙️ Build & Run

🔧 Requirements

• GCC or Clang
• POSIX-compliant environment (Linux, macOS)
• Make

▶ Compile

make

▶ Run

./emergency_system

▶ Example Output

[INFO] Emergency received: ID=42, PRIORITY=3
[INFO] Added to priority queue
[INFO] Dispatcher assigning emergency 42 to Responder #2
[INFO] Responder #2 started mission (duration: 12s)
[INFO] Responder #2 returned from mission

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🧠 Core Concepts Demonstrated

-Concurrency and synchronization

-Thread lifecycle management

-Message-passing via POSIX MQ

-Priority-based scheduling

-Realistic simulation of time-based processes

-Modular design and clean architecture

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👤 Author

Alessandro Han

Computer Science, University of Pisa

LinkedIn: https://www.linkedin.com/in/alessandro-han-b87391223/