File Synchronization System (FSS)

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📌 TL;DR

A Linux-based file synchronization system implemented in C.
Uses multi-process architecture, pipes, inotify, and low-level file operations to keep directories in sync.
Developed as part of a university systems programming course, demonstrating strong skills in system-level programming, concurrency, and IPC.

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🚀 Features

• Multi-process architecture (fork, exec)
• Inter-process communication with pipes & signals
• Real-time directory monitoring using inotify
• Initial + incremental synchronization across directories
• Console interface with commands (add, shutdown)
• Logging system for manager and console
• Detailed execution & error reports

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🛠️ Technologies & Skills Demonstrated

• C programming (Linux, system-level)
• Concurrency & Process Management
• Event-driven programming (inotify, poll)
• Data structures (linked list for sync state tracking)
• Low-level file I/O (open, read, write, unlink)
• Build automation with Makefile

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📂 Project Structure

hw/
├── fss_manager/       # Core manager process
│   ├── config_file    # User-defined configuration (required)
│   ├── manager_log    # Manager log file
│   └── ...
├── fss_console/       # Command-line console interface
│   └── console_log    # Console log file
├── worker/            # Worker process handling sync operations
├── Makefile           # Build automation
└── ...

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⚙️ Installation & Usage

1. Compile

make all
# or
make

2. Run

Open two terminals:

Terminal 1 (Manager):

make run_fss_manager

Terminal 2 (Console):

make run_fss_console

⚠️ Important Notes:

• config_file must be inside the fss_manager directory.
• All source_dir and target_dir paths should be relative to fss_manager.
  • Example: ../source_dir ../target_dir if outside, or just source_dir if inside.
• To change arguments, edit the Makefile.

3. Console Commands

add <source_dir> -> <target_dir>
shutdown

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📖 Implementation Details

Manager

• Reads configuration and spawns workers for synchronization.
• Tracks sync state with a linked list (sync_info_mem_store) keyed by:
  • Watch descriptor (inotify)
  • Folder name
  • Worker PID
• Handles pipes, signals, and logging.
• Runs two phases: initial sync, then incremental monitoring via inotify.

Console

• Accepts user commands and communicates via named pipes.
• Supports add and shutdown.
• Maintains a log file for all activity.

Worker

• Handles file copy, delete, and modify using low-level system calls.
• Produces execution reports and error logs.
• Supports full directory sync and single-file operations.

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📌 Known Limitations

• Console log output incomplete.
• No .sh wrapper provided.
• Some commands parsed but not fully executed.
• add may behave differently depending on the environment.
• Logging not fully consistent across components.

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🔮 Future Improvements

• Add more console commands (remove, modify).
• Improve error handling and logging.
• Provide shell scripts for easier execution.
• Enhance cross-system stability.

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🎓 Academic Context

This project was developed for a university systems programming course, demonstrating proficiency in:

• Linux system-level programming
• Process & resource management
• Inter-process communication (IPC)
• Real-time file synchronization

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