0x16. C - Simple Shell
C
Group project
Syscall
By: Julien Barbier
Weight: 10
Project to be done in teams of 2 people (your team: Mfumu Mabunda, Olaoluwa Anigboro-Napoleon)
Project over - took place from Nov 2, 2022 6:00 AM to Nov 17, 2022 6:00 AM
An auto review will be launched at the deadline
In a nutshell…
Contribution: 100.0%
Auto QA review: 0.0/55 mandatory & 0.0/76 optional
Altogether: 0.0%
Mandatory: 0.0%
Optional: 0.0%
Contribution: 100.0%
Calculation: 100.0% * (0.0% + (0.0% * 0.0%) ) == 0.0%
Challenge #3 has started!
Concepts
For this project, we expect you to look at these concepts:
Everything you need to know to start coding your own shell
Approaching a Project
Background Context
Write a simple UNIX command interpreter.
^ “The Gates of Shell”, by Spencer Cheng, featuring Julien Barbier
Resources
Read or watch:
Unix shell
Thompson shell
Ken Thompson
Everything you need to know to start coding your own shell concept page
man or help:
sh (Run sh as well)
Learning Objectives
At the end of this project, you are expected to be able to explain to anyone, without the help of Google:
General
Who designed and implemented the original Unix operating system
Who wrote the first version of the UNIX shell
Who invented the B programming language (the direct predecessor to the C programming language)
Who is Ken Thompson
How does a shell work
What is a pid and a ppid
How to manipulate the environment of the current process
What is the difference between a function and a system call
How to create processes
What are the three prototypes of main
How does the shell use the PATH to find the programs
How to execute another program with the execve system call
How to suspend the execution of a process until one of its children terminates
What is EOF / “end-of-file”?
Copyright - Plagiarism
You are tasked to come up with solutions for the tasks below yourself to meet with the above learning objectives.
You will not be able to meet the objectives of this or any following project by copying and pasting someone else’s work.
You are not allowed to publish any content of this project.
Any form of plagiarism is strictly forbidden and will result in removal from the program.
Requirements
General
Allowed editors: vi, vim, emacs
All your files will be compiled on Ubuntu 20.04 LTS using gcc, using the options -Wall -Werror -Wextra -pedantic -std=gnu89
All your files should end with a new line
A README.md file, at the root of the folder of the project is mandatory
Your code should use the Betty style. It will be checked using betty-style.pl and betty-doc.pl
Your shell should not have any memory leaks
No more than 5 functions per file
All your header files should be include guarded
Use system calls only when you need to (why?)
Write a README with the description of your project
You should have an AUTHORS file at the root of your repository, listing all individuals having contributed content to the repository. Format, see Docker
GitHub
*There should be one project repository per group. If you and your partner have a repository with the same name in both your accounts, you risk a 0% score. Add your partner as a collaborator. *
More Info
Output
Unless specified otherwise, your program must have the exact same output as sh (/bin/sh) as well as the exact same error output.
The only difference is when you print an error, the name of the program must be equivalent to your argv[0] (See below)
Example of error with sh:
$ echo "qwerty" | /bin/sh
/bin/sh: 1: qwerty: not found
$ echo "qwerty" | /bin/../bin/sh
/bin/../bin/sh: 1: qwerty: not found
$
Same error with your program hsh:
$ echo "qwerty" | ./hsh
./hsh: 1: qwerty: not found
$ echo "qwerty" | ./././hsh
./././hsh: 1: qwerty: not found
$