Game Syscalls Flashcards

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Students with: open(), read(), close() step forward in order.

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The program should create a directory named "Hunt1", create a file called "treasures.dat" inside it, write a welcome message, and handle errors at every step.

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1. 1. creat or open

2. 2. fstat

3. 3.write

4. 4. close

5. 5. perror for all of them

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LEVEL 2

A program needs to create a folder, create a file inside it, read some data, and close it.

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Expected calls: mkdir(), open(), read(), close()

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LEVEL 3
Inside Directory Dir1, create a file and write to it the text "Hello", read the message from the same file. If any step fails, an error should be printed.

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Expected calls: mkdir(), open() or creat(), write(), close(), open(), read(), close(), perror() for each.

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LEVEL 4

The program should check if "entry" is a regular file. In case it is, it reads from it 4 bytes. The read content is written at the end (be careful here) to a newly created file2.txt. In case is a directory, it must be renamed it. In case it is a symbolic link, it removes the link.

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1. lstat() — Check metadata of entry

2. S_ISREG — Evaluate st_mode to ensure it's a regular file

3. open() — Open entry in read-only mode

4. read() — Read 4 bytes from file1.txt

5. close() — Close file1.txt

6. creat() or open()— Open file2.txt in write or create mode

7. lseek() - for writing at the end

8. write() — Write the 4 bytes read into file2.txt

9. close() — Close file2.txt

10. S_ISDIR() + rename()

11. S_ISLNK + unlink()

perror() — Should step in any time an error occurs

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LEVEL 5

Create a directory called Hunt1, add a treasure file and a log file, and create a symbolic link to the log file. At the end, remove the directory.

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• ✅ mkdir() — Create the Hunt1 directory

• ✅ open() — Open (or create) Hunt1/treasures.dat with O_CREAT

• ✅ close() — Close the treasures file

• ✅ open() — Open (or create) Hunt1/logged_hunt with O_CREAT

• ✅ close() — Close the log file

• ✅ symlink() — Create symbolic link from Hunt1/logged_hunt to logged_hunt-Hunt1 in the root directory

• rmdir() -

• 🔁 perror() — May appear after any step to report an error if one occurs (e.g., directory already exists)

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LEVEL 6

You are given a file name.
The program should:

1. Check whether the path is a symbolic link

2. If it is, remove its link to the target file.

3. Check whether is a regular file, in which case we delete the file.

4. Check whether is a directory, in which case we delete it.

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✅ Required System Calls & Macros (in execution order)

StepFunction/MacroPurpose1️⃣lstat()Get file metadata without following symlinks2️⃣S_ISLNK()Check if it's a symbolic link3️⃣unlink()Remove symbolic link

✔️ At this point, if it was a symlink, the job is done.
Otherwise, continue:

StepFunction/MacroPurpose4️⃣stat()Get metadata by following symlinks (e.g., if it points to a real file)5️⃣S_ISREG()Check if it’s a regular file6️⃣unlink()Delete regular file

StepFunction/MacroPurpose7️⃣S_ISDIR()Check if it’s a directory8️⃣rmdir()Remove the directory (if empty)

🔁 perror() is used for error handling in any failure (e.g., file not found, permission denied)