Unix Systems Programming: Lab 4

README

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2. Before starting, please reviews lecture4 note carefully, for each part of lab, there is also specified reading assignment;
3. Please pay attention to "DELIVERABLES" instruction in each part;
4. Turn the lab assignment in by email to the grader by the due date.

LAB 4

1. Signal Handling
   

   
   Write a signal handler that catches the CTRL-C (SIGINT signal 2) and SIGUSR1 (signal 10) signals.   Your process should not by default exit on CTRL-C back to your shell.  You may want to look on the BLP example on signals, or Chapter 6 of Molay's text if you're using that.  The following requirements apply:
   
   
2. You should accumulate the handling of CTRL-C in the handler.  That is to say, you should have a variable counter accumulate each time the handler is called, and print out the current count in the handler.  For instance, if you've hit CTRL-C 6 times, your handler should print out something to the effect of "You've pressed Ctrl-C 6 times.  Aren't you getting the message that I'm invulnerable?"  
3. Your program should accept a command line argument that specifies the MAXSTOPS allowed, after which, Ctrl-C is handled in the default way (i.e., the program terminates).  So if the user passes in '10' on the command line, the program prints out it's message above the first 9 times, but the 10th time CTRL-C is pressed, the default action applies (program termination).
   
4. You should print out a message that states that your program received the SIGUSR1 signal when it is handled.  You should be able to issue a kill command to send your program the SIGUSR1 signal, and have that signal handled properly (by printing out a receipt notification) and then continue to function and handle subsequent CTRL-C and SIGUSR1 signals.

Please following these steps to finish this part smoothly:

• Read "signal" session in Chapter 11 of BLP textbook or in Chapter 6 of Molay's text.
• Read and understand the example code first.
• Understand that handling SIGUSR1 is one of the most primitive forms of interprocess communication in Unix (i.e., you are communicating with another process).

DELIVERABLES: your source file(s) (e.g., my_sig.c), a makefile, and a README as described in the submission faq

MARKS DISTRIBUTION

1. Excercise 1:
• 5.5 points: code that compiles, executes, and handles SIGINT as in point 4.1


• 5.5 points: correct accumulation of signal counts as in point 4.2


• 5.5 points: correct handling of MAXSTOPS argument as in point 4.3


• 5.5 points: correct handling of SIGUSR1 as in point 4.4
• 3 points: proper submission according to submission guidelines 



Total Marks: 25

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Atilla Soner Balkir