SOchain - Transaction Simulator with SOT Token

Introduction

SOchain is a C-based application designed to simulate a transaction system for a cryptocurrency token called SOT (SO Token). The system incorporates operating system concepts such as process management, shared memory, process synchronization (with semaphores), signals, alarms, and file I/O.

This project was developed as part of the Operating Systems course at the Faculty of Sciences, University of Lisbon.

Project Structure

The project follows this directory structure:

SOCHAIN/
|-- bin/                # Executable files
|-- inc/                # Header files (.h)
|-- obj/                # Object files (.o)
|-- src/                # Source code files (.c)
|-- makefile            # Compilation script
|-- README.md           # This document
|-- args.txt            # Input arguments file
|-- settings.txt        # Settings file (log, stats, period)

Compilation

To manage the project, use the following commands:

• Compile the project: make all
• Compile only: make
• Clean compiled files: make clean
• Recompile from scratch: make re

Execution

Phase 2: Run the program using:

./bin/SOchain args.txt settings.txt

Where:

• args.txt contains, line by line:
  1. Initial balance for each wallet (init_balance)
  2. Number of wallets (n_wallets)
  3. Number of servers (n_servers)
  4. Buffer size (buff_size)
  5. Maximum number of transactions (max_txs)
• settings.txt contains, line by line:
  1. Log file name (e.g., log.txt)
  2. Statistics file name (e.g., stats.txt)
  3. Period for periodic statistics print (in seconds, use 0 to disable)

Example args.txt:

100.0
2
2
10
50

Example settings.txt:

log.txt
stats.txt
5

Example Run

./bin/SOchain args.txt settings.txt

Functionality

The program provides an interactive menu for managing transactions:

• bal <id>: Check the balance of a specific wallet.
• trx <src_id> <dest_id> <amount>: Create a transaction from one wallet to another.
• rcp <id>: Retrieve the receipt of a transaction.
• stat: Display the current state of the system.
• help: Show the list of available commands.
• end: Terminate the SOchain execution.

New Features in Phase 2

• Synchronization: All access to shared memory is protected by semaphores (producer/consumer model).
• File Input: Arguments are read from args.txt and settings from settings.txt.
• Logging: All user operations are logged to the file specified in settings.txt with timestamps.
• Periodic Statistics: If the period in settings.txt is greater than 0, the system prints the status of all transactions periodically.
• Signal Handling: The program handles SIGINT (CTRL+C) to terminate gracefully, releasing all resources.
• Statistics File: On termination, final statistics are written to the file specified in settings.txt.

Main Modules

• main.c/h: Manages process creation and user interaction.
• process.c/h: Handles process creation and termination.
• memory.c/h: Manages dynamic and shared memory allocation.
• wallet.c/h: Signs transactions and forwards them to servers.
• server.c/h: Validates, processes, and records transactions.
• synchronization.c/h: Implements semaphores for synchronization.
• clog.c/h: Handles logging of user operations.
• csettings.c/h: Reads configuration files.
• ctime.c/h: Manages timestamps for transactions.
• csignal.c/h: Handles signals and alarms.
• cstats.c/h: Handles statistics output.

Testing

To test the program:

1. Compile:

   make

2. Prepare input files: Edit src/args.txt and src/settings.txt as shown above.
3. Run:

   ./bin/SOchain src/args.txt src/settings.txt

4. Interact: Use the commands (bal, trx, rcp, stat, help, end) as described above.
5. Check outputs:
   • Log file (e.g., log.txt) for operation history.
   • Statistics file (e.g., stats.txt) for final stats.
   • Periodic statistics on the terminal if enabled.
6. Test signals: Press CTRL+C to ensure the program terminates gracefully and writes statistics.

Authors

Grupo 40

• Rodrigo Frutuoso - 61865
• Simão Alexandre - 61874
• Tiago Leite - 61863

Notes

• The project was developed and tested in a Linux environment.
• All synchronization, logging, and signal handling are implemented in this phase.

License

This project is for academic purposes only and should not be used for commercial applications.