Minitalk

Minitalk is a small data exchange program developed as part of the 42 School curriculum. It implements a communication channel between a client and a server using UNIX signals.

📝 Description

The purpose of this project is to create a communication program in C. The program consists of a server and a client. The server launches first and prints its PID. The client then takes the server's PID and a string as arguments, and sends the string to the server. The server receives the string and prints it.

The communication is achieved solely using two UNIX signals: SIGUSR1 and SIGUSR2.

✨ Features

Mandatory Part

• Server:
  • Starts and prints its PID.
  • Waits for incoming signals.
  • Decodes the received signals into characters and prints the string.
• Client:
  • Takes the server's PID and a string as arguments.
  • Converts the string into a series of signals.
  • Sends the signals to the server.
• Communication:
  • Uses SIGUSR1 to represent a 1 bit.
  • Uses SIGUSR2 to represent a 0 bit.
  • Supports Unicode characters.

Bonus Part

• Acknowledgement: The server sends a signal back to the client to confirm that the message has been fully received.
• Unicode Support: Fully supports standard and extended ASCII characters (already implicit in the mandatory part but explicitly handled).

🛠️ Compilation

To compile the project, run the following command in the root directory:

make

This will generate two executables: server and client.

To compile the bonus version (with message acknowledgement), run:

make bonus

This will generate server_bonus and client_bonus.

🚀 Usage

1. Start the Server

First, run the server. It will print its PID and wait for messages.

./server

Output:

Pid: 12345

2. Run the Client

Open a new terminal window and run the client with the server's PID and the message you want to send.

./client 12345 "Hello, Minitalk!"

The server will print:

Hello, Minitalk!

Bonus Usage

If you compiled with make bonus:

1. Start the bonus server:

   ./server_bonus

2. Run the bonus client:

   ./client_bonus <PID> "Hello, Bonus!"

   The client will receive a confirmation signal and print:

   Message confirmed by server!
   

⚙️ Technical Details

• The communication relies on bitwise operations.
• Each character is broken down into 8 bits.
• The client iterates through each bit of every character in the string.
• SIGUSR1 is sent if the bit is 1.
• SIGUSR2 is sent if the bit is 0.
• The server reconstructs the character bit by bit. Once 8 bits are received, it prints the character and resets the bit counter.
• usleep is used to ensure the server has enough time to process each signal.

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Developed by sdadak for 42 Istanbul.