Assignments on Linux System Calls (Difficulty Level: Beginner)

Here are assignments related to each category of Linux system calls to help understand their usage and functionality. These exercises will also give you practical experience with interacting with Linux system calls from user space.

1. Process Management

Assignment:

• Task: Write a C program that:

• Creates a child process using fork().

• In the child process, call execve() to run a command (e.g., ls or pwd).

• In the parent process, wait for the child to finish using wait().

• Print the process IDs of both the parent and the child.

Objective: Understand process creation, execution, and synchronization between parent and child processes.

2. File Operations

Assignment:

• Task: Write a C program that:

• Opens a file (you can create a new text file or use an existing one) with open().

• Writes some data to the file using write().

• Reads the data from the file using read().

• Closes the file using close().

Objective: Learn how to open, write, read, and close files using system calls.

3. Memory Management

Assignment:

• Task: Write a C program that:

• Allocates a memory region using mmap() and maps a file into memory.

• Modify the content of the mapped file.

• Unmaps the file using munmap().

Objective: Understand memory mapping and the mapping/unmapping process.

4. Signal Handling

Assignment:

• Task: Write a C program that:

• Creates a signal handler using signal() to catch SIGINT (Ctrl+C).

• Prints a message whenever SIGINT is received.

• In the main function, use sleep() and wait for the signal.

Objective: Learn how to handle signals and write signal handlers.

5. Inter-Process Communication (IPC)

Assignment:

• Task: Write a C program that:

• Creates a pipe using pipe().

• Forks a child process.

• The parent sends a message to the child process through the pipe using write().

• The child receives the message using read() and prints it.

Objective: Understand basic IPC using pipes.

6. Networking

Assignment:

• Task: Write a C program that:

• Creates a server and client using socket().

• The server binds to a port and listens for incoming connections.

• The client connects to the server and sends a message.

• The server receives the message and sends a response back to the client.

• Both server and client close the socket after communication.

Objective: Get hands-on experience with socket programming and basic client-server communication.

7. File System Management

Assignment:

• Task: Write a C program that:

• Creates a new directory using mkdir().

• Changes the current working directory to the new directory using chdir().

• Verifies the current directory using getcwd().

• Deletes the directory using rmdir().

Objective: Understand basic file system management system calls like directory creation and removal.

8. User and Group Management

Assignment:

• Task: Write a C program that:

• Uses getuid() and getgid() to get the user and group IDs of the current process.

• Changes the user ID and group ID using setuid() and setgid() (for this, your program may need to run as a superuser).

• Prints the new user and group IDs.

Objective: Learn how user and group management system calls work.

9. Time Management

Assignment:

• Task: Write a C program that:

• Prints the current time using time() or gettimeofday().

• Makes the process sleep for 2 seconds using sleep() or nanosleep().

• Prints the current time again and calculates the difference.

Objective: Understand time-based system calls and how to work with time in Linux.

10. Filesystem and Disk Operations

Assignment:

• Task: Write a C program that:

• Creates a file and writes some data into it.

• Calls fsync() to ensure data is written to disk.

• Verifies that data is synced correctly by checking the contents before and after the fsync() call.

Objective: Learn about file synchronization using fsync().

Bonus Challenge:

Assignment:

• Task: Create a simple Linux shell that:

• Reads user input as a command.

• Uses fork() to create a child process.

• Uses execve() to run the command entered by the user.

• The shell should continue to prompt the user for commands until exit is typed.

Objective: Combine various system calls like fork(), execve(), wait(), etc., into a practical project that mimics a basic shell.

Conclusion:

Each assignment is designed to focus on one aspect of system calls in Linux, from process management to networking, file operations, memory management, and signal handling. Completing these exercises will deepen your understanding of how user-space programs interact with the kernel through system calls. You can extend these assignments or modify them to explore more advanced use cases and features.