Simple Web Server

This program was designed for and designed on FreeBSD 14.1. It is the group project from the class CS631 Advanced Programming in the Unix Enviroment as taught by Jan Schaumann. The objective of this assignemnt is to write a simple web server that speaks a limited version of HTTP/1.0 as defined in RFC1945. For more inforamtion on the specific of the assignment, please visit the assigment page.

This program is made simply for me to learn more about interprocess communication and sockets.

Assignment Goals

The objective of this assignment is to write a simple web server that speaks a limited version of HTTP/1.0 as defined in RFC1945. Your program should behave as one would expect from a regular system daemon. That is, it should detach from the controlling terminal and run in the background, accept multiple simultaneous connections, not generate any messages on stdout unless in debugging mode etc.

Important: This is not a production server. It has limited functionality, probable bugs and security issues. It is purely made for educational purposes. It is not recommended that you use it exposed to the internet.

Building the Program

To build the program, run cmake in the main directory of the program. Ensure you have cmake installed on your system.

To build the program, follow these steps:

1. Navigate to the main directory of the program.
2. Run the following commands:

$ ./setup.sh

The setup file will run the Makefile, as well as create several files and subdirectories. The files will be a mix of HTML files, CGI scripts, and text files.

.
├── cgi-bin
│   ├── guestBook.c
│   ├── guestBook.cgi
│   ├── helloWorld.c
│   └── helloWorld.cgi
├── cgi-data
├── index.html
├── simple_server
├── subNoIndex
│   ├── test1.txt
│   └── test2.txt
└── subWithIndex
    └── index.html

Should you wish to only build the server instead run the command:

make

To remove the only object files after compiling the binary run the following command

make clean-obj

To remove all files created during the make process including the binary run the following

make clean

If the application is built on another *nix machine it is recommended that the code be reviewed for any library or system calls that may need to be refactored.

Running the Program

./simple_server [option] [path] ...

Replace [options] with any applicable flags and [path] with the options below. One started the server will run and provide requested files through a web browser, cURL or even telnet.

−c dir Allow execution of CGIs from the given directory.

−d Enter debugging mode. That is, do not daemonize, only accept one connection at a time and enable logging to stdout.

−i address Bind to the given IPv4 or IPv6 address. If not provided, Simple_Server will listen on all IPv4 and IPv6 addresses on this host.

−l file Log all requests to the given file. See LOGGING for details.

−p port Listen on the given port. If not provided, Simple_Server will listen on port 8080.

Once the server is running it can be accessed in a browser with http://localhost:[portnumber]. If using the setup script, the server will load the index.html file in the directory.

Closing the application

Simple_server is designed to run as a daemon and will be inaccessable from the terminal unless the -d flag has been enabled.

To close the application while running as a daemon you will need to kill the process using the process ID. The process ID can be found using the sockstat command and grepping the respective port number.

$ ./simple_server 
$ sockstat | grep 8080
jholloway simple_server 31863 3   tcp4   *:8080                *:*
jholloway simple_server 31863 4   tcp6   *:8080                *:*
$ kill 31863

Memory Management

This program has been carefully developed to handle memory management correctly, ensuring no memory leaks. Valgrind was used extensively to check for and fix any memory issues.

Use of AI Tools (Claude)

This project makes use of Claude, an AI assistant, in a specific and limited capacity for educational purposes. It's important to understand the role Claude plays in this development process:

What Claude IS used for:

• Makefile Revisions: Original Makefile has been improved upon for expediency as documentation, formatting, etc. options have increased.
• Code review and analysis: Identifying potential bugs, security vulnerabilities, and performance issues
• Documentation assistance: Helping to structure and improve documentation
• Educational guidance: Providing explanations of systems programming concepts and best practices
• Performance analysis: Helping interpret profiling data and benchmark results
• Linter scripting: assistance in ensuring cppcheck follows BSD coding standards over Google standards
• Formatting: Assisted in writing a .clang-format file to ensure code style follows BSD coding styles

What Claude is NOT used for:

• Code generation: All code in this repository is human-written
• Implementation: Problem-solving and coding decisions are made independently
• Shortcuts: Claude does not write solutions or complete assignments

Educational Philosophy

The goal is to use AI as a knowledgeable tutor and code reviewer, similar to how one might work with a senior engineer or teaching assistant. All code remains my own work, for better and worse. The AI serves as an additional layer of review and learning support, not as a replacement for understanding the underlying systems programming concepts.

This approach ensures:

• Deep learning of systems programming fundamentals
• Ownership of all implementation decisions
• Authentic problem-solving experience
• Professional-quality code review practices

For more details about my educational philosophy and approach to using AI tools in learning systems programming, please see my blog post: Benchmarking and Rebuilding an Old Web Server - Part 1