Lab Assignment--System Calls for I/0

Lab Code

   wget www.labs.cs.uregina.ca/330/SystemCall_IO/Lab7.zip
   unzip Lab7.zip

Exercise Description

The idea of this exercise is to communicate between a child and a parent using a shared file that the user will specify.

Your program will require the name of the file to be sent as a command line argument (argv[1])

A skeleton algorithm is provided below:

1. Check that the number of command line arguments is 2. If it isn't, produce an error message. Note: you cannot use perror here.
    
2. Use fork to produce a child and parent
• Child will:
• open the file for writing (make sure to use the "create" flag and permissions for the user to read and write)
• check for errors on opening and use perror to describe the error.
• read from standard input (until end of file,ie., you type CTRL-D)
• write to the file
• when done, close the file
• Parent will:
• wait for the child
• open the file for reading
• check for errors on opening and use perror to describe the error.
• write a message that you are in the parent
• read from the file (until end of file)
• write to standard output
• when done, close the file

Don't forget to handle the error situation

Deliverables

Submit 2 files to URCourses

1. Your Code
2. Script containing the following commands (executable is called myIO):
   1. ls -l (Goal: show that no .txt files exist aside from your script file)
   2. ./myIO (Result: error message-not enough arguments)
   3. ./myIO file.txt (Result: no errors; gets input from the keyboard until you type CTRL-D; and creates file.txt with contents of what you typed)
   4. ls -l (Goal: show that file.txt has been created)
   5. cat file.txt (Goal: display the contents of the output file)
   6. ./myIO /file.txt (Result: two error messages - (1) permission denied on creating and (2) no such file when opening for reading- on file.txt in the root directory)

Notes

• Do not create a zip file
• Submission is on UR Courses
• Submit your own work
• Please properly indent your work. I will deduct marks for ziggy-zaggy code.
• Be mindful that your assignment is due two hours before the start of your next lab