system-programming/exercises

🗂️ Exercise Index – Linux System Programming

This is an organized list of all exercises completed so far, including a brief description and links to related resources or files.

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📁 mycp

Description: A simple file copy utility implemented in C using low-level system calls (open, read, write, close).

• 📄 README
• 📂 Directory: mycp/
• ✅ Features:
  • Error handling via perror and errno
  • Safe loop with EINTR handling
  • Proper resource cleanup
  • Integrated unit tests and Valgrind checks

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🌳 tree

Description: A basic reimplementation of the Unix tree utility that recursively lists directories and files.

• 📄 README
• 📂 Directory: tree/
• ✅ Features:
  • Recursive traversal using opendir and readdir
  • Directory depth display
  • Unit tests with mocks for directory structure
  • Scripted test automation with Valgrind integration

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🐚 run_scripts

Description: A simple C program that sequentially executes one or more bash scripts, printing each script’s exit status.

• 📄 README
• 📂 Directory: run_scripts/
• ✅ Features:
  • Uses fork() and execlp() to run each script in a child process
  • Waits for each child to finish before executing the next
  • Reports normal exit code or termination by signal
  • Includes example test scripts and memory checks with Valgrind
  • Makefile with targets: build, run, test, valgrind, and clean

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📥 downloader

Description: A multi-threaded simulated file downloader implemented in C using POSIX threads (pthreads).

• 📄 README
• 📂 Directory: downloader/
• ✅ Features:
  • Each thread simulates downloading a file by printing periodic progress updates
  • Synchronization using pthread APIs
  • Demonstrates creation, execution, and joining of threads
  • Makefile included with standard targets

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🧠 memory_analyzer

Description: A simple memory analyzer that allocates memory blocks of different sizes and prints current memory usage.

• 📄 README
• 📂 Directory: mem_analyzer/
• ✅ Features:
  • Allocates blocks using malloc and frees them after measurement
  • Reports current memory usage via /proc/self/status
  • Minimal implementation aligned with the exercise objectives
  • Makefile included with standard targets

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🚦 signal_handler

Description: A C program demonstrating robust signal handling for SIGINT and SIGUSR1 using sigaction with SA_SIGINFO.

• 📄 README
• 📂 Directory: signal_handler/
• ✅ Features:
  • Handles SIGINT up to three times before exiting
  • Handles SIGUSR1 with a simple message
  • Masks signals during handler execution to avoid reentrancy issues
  • Includes comments and clear separation of handler logic
  • Makefile included with standard targets

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🔧 Tooling & Automation

Shared tools and scripts used across projects:

• Makefile with:
  • Targets for build, test, valgrind, and clean
• Shell script for automated tests: run_tests.sh
• Valgrind memory check reports generated automatically