https://github.com/mbdanielcrespo/minitalk
Inter-process communication (IPC) using UNIX signals project. It involves creating a client-server system where the client sends messages to the server by encoding characters bit-by-bit using SIGUSR1 and SIGUSR2 signals.
https://github.com/mbdanielcrespo/minitalk
bitwise-operators getpid ipc kill pause signal-processing sigusr1 sigusr2 unix
Last synced: 6 months ago
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Inter-process communication (IPC) using UNIX signals project. It involves creating a client-server system where the client sends messages to the server by encoding characters bit-by-bit using SIGUSR1 and SIGUSR2 signals.
- Host: GitHub
- URL: https://github.com/mbdanielcrespo/minitalk
- Owner: mbdanielcrespo
- Created: 2023-10-10T13:29:23.000Z (over 2 years ago)
- Default Branch: main
- Last Pushed: 2025-04-17T10:54:43.000Z (11 months ago)
- Last Synced: 2025-05-21T08:19:01.821Z (10 months ago)
- Topics: bitwise-operators, getpid, ipc, kill, pause, signal-processing, sigusr1, sigusr2, unix
- Language: C
- Homepage:
- Size: 236 KB
- Stars: 0
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
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README
# 📡 minitalk
## 📝 Introduction
**minitalk** is a 42 School project focused on creating a small data exchange program using UNIX signals. The project consists of a client and server that communicate using only SIGUSR1 and SIGUSR2 signals.
> "A simple but powerful implementation of inter-process communication using signals."
The goal is to transmit any string from a client program to a server program using only UNIX signals as the communication method.
## 🎯 Project Objectives
- Implement a communication protocol using only UNIX signals
- Create a client that can send messages to a server
- Create a server that can receive and display messages
- Handle the transmission of strings of any length
- Implement proper error handling and signal management
- Learn about processes, signals, and bitwise operations
## 🧩 Project Structure
The project consists of three main components:
```
minitalk/
├── inc/
│ └── minitalk.h # Header file with prototypes and includes
├── src/
│ ├── client.c # Client implementation
│ └── server.c # Server implementation
└── Makefile # Compilation instructions
```
## 🛠️ Implementation Details
### **minitalk.h**
The header file includes:
- Standard library includes
- Custom function prototypes
- Wait time definition for signal transmission
- Utility function declarations
### **client.c**
The client program sends messages to the server:
| Function | Description |
|----------|-------------|
| **pid_error** | Validates command line arguments and PID format |
| **send_ch_by_bit** | Sends a single character by breaking it into 8 bits |
| **send_len_by_bit** | Sends string length as 32 bits to prepare the server |
| **main** | Parses arguments and orchestrates the message transmission |
### **server.c**
The server program receives and displays messages from clients:
| Function | Description |
|----------|-------------|
| **recive_len** | Reconstructs the length of the incoming message from bits |
| **recive_str** | Reconstructs characters from bits and builds the final string |
| **recive_client_data** | Signal handler that processes incoming signals |
| **main** | Displays PID, sets up signal handlers, and waits for client connections |
## 💡 Communication Protocol
1. **Connection Establishment**:
- Server starts and displays its PID
- Client uses the server's PID to target signal transmission
2. **Message Transmission**:
- Client first sends the string length (32 bits) to the server
- Server allocates memory based on the received length
- Client sends each character of the string (8 bits per character)
- Server reconstructs each character and builds the complete message
3. **Bit Encoding**:
- SIGUSR1 represents bit value 1
- SIGUSR2 represents bit value 0
- Bits are sent sequentially with a delay between signals
## 🔍 Key Features
- Binary data transmission using only two signals
- Support for messages of any length
- Error handling for invalid PIDs
- Memory management for received strings
- Bitwise operations for encoding/decoding messages
## 🧠 Skills Developed
- Process management and inter-process communication
- Signal handling in UNIX systems
- Bitwise operations and binary data manipulation
- Memory management
- Protocol design and implementation
---
### 📊 Project Stats
| Metric | Value |
|--------|-------|
| Final Score | 80/100 |
| Lines of Code | ~150 |
| Signal Types | 2 (SIGUSR1, SIGUSR2) |
