Operating Systems 2021F: Assignment 2 - Revision history

Soma at 14:03, 14 October 2021

2021-10-14T14:03:24Z

← Older revision		Revision as of 14:03, 14 October 2021
Line 202:		Line 202:
	echo "Blastoff!"		echo "Blastoff!"
	</syntaxhighlight>		</syntaxhighlight>

			==Solutions==

			[https://homeostasis.scs.carleton.ca/~soma/os-2021f/solutions/assign2-sol.txt Assignment 2 solutions]

Soma: /* Questions */

2021-10-12T14:35:57Z

Questions

← Older revision		Revision as of 14:35, 12 October 2021
Line 33:		Line 33:

	# [2] If we read from /dev/null, what data do we get? How can you verify this?		# [2] If we read from /dev/null, what data do we get? How can you verify this?
	# [2] 3000capture requires commands to be fully qualified pathnames. How can you modify 3000capture so that if a command doesn't ~~have~~ a / ~~in it~~, 3000capture searches the current PATH to find the right program? If PATH isn't defined it should search a default set of directories.		# [2] 3000capture requires commands to be fully qualified pathnames. How can you modify 3000capture so that if a command doesn't start with a /, 3000capture searches the current PATH to find the right program? If PATH isn't defined it should search a default set of directories.
	# [2] What is the purpose of the fflush() call in parent() at line 36? Why isn't it needed elsewhere in parent()?		# [2] What is the purpose of the fflush() call in parent() at line 36? Why isn't it needed elsewhere in parent()?
	# [2] How could you fix 3000capture so it sends its output to the file specified by the CAPTURE environment variable? If there is no CAPTURE environment variable, it should use the same default as it does currently.		# [2] How could you fix 3000capture so it sends its output to the file specified by the CAPTURE environment variable? If there is no CAPTURE environment variable, it should use the same default as it does currently.

Soma: /* Questions */

2021-10-10T20:24:53Z

Questions

← Older revision		Revision as of 20:24, 10 October 2021
Line 44:		Line 44:
	#* Sends a SIGTERM signal to its child		#* Sends a SIGTERM signal to its child
	#* Waits at least one second		#* Waits at least one second
	#* If the child has terminated, it reports ~~"Child successfully~~ terminated ~~with status %d" (with %d being the status)~~		#* If the child has terminated, it reports how the child has terminated, whether from a signal or whether it returned normally.
	#* If the child has not terminated, it reports "Child still running, aborting." and exits with a return value of -10.		#* If the child has not terminated, it reports "Child still running, aborting." and exits with a return value of -10.

Soma: /* Questions */

2021-10-10T18:11:50Z

Questions

← Older revision		Revision as of 18:11, 10 October 2021
Line 43:		Line 43:
	#* Prints "SIGUSR1 received, shutting down."		#* Prints "SIGUSR1 received, shutting down."
	#* Sends a SIGTERM signal to its child		#* Sends a SIGTERM signal to its child
	#* Waits one second		#* Waits at least one second
	#* If the child has terminated, it reports "Child successfully terminated with status %d" (with %d being the status)		#* If the child has terminated, it reports "Child successfully terminated with status %d" (with %d being the status)
	#* If the child has not terminated, it reports "Child still running, aborting." and exits with a return value of -10.		#* If the child has not terminated, it reports "Child still running, aborting." and exits with a return value of -10.

Soma at 16:37, 8 October 2021

2021-10-08T16:37:59Z

← Older revision		Revision as of 16:37, 8 October 2021
Line 1:		Line 1:
	~~'''This assignment is not yet finalized.'''~~

	Please submit the answers to the following questions via Brightspace by October 14, 2021 by 10 AM. There are 20 points in 9 questions.		Please submit the answers to the following questions via Brightspace by October 14, 2021 by 10 AM. There are 20 points in 9 questions.

Soma at 04:58, 7 October 2021

2021-10-07T04:58:05Z

← Older revision		Revision as of 04:58, 7 October 2021
Line 1:		Line 1:
	'''This assignment is ~~still being developed~~.'''		'''This assignment is not yet finalized.'''

			Please submit the answers to the following questions via Brightspace by October 14, 2021 by 10 AM. There are 20 points in 9 questions.

			Submit your answers as a plain text file following [https://homeostasis.scs.carleton.ca/~soma/os-2021f/templates/comp3000-a2-template.txt this template]. Name your answer file "<username>-comp3000-assign2.txt" (where username is your MyCarletonOne username).

			'''Your answers will be parsed by a script in order to help with grading so please preserve the format of the template.''' Make sure the file remains a plain text file! No other formats will be accepted.

			Don't forget to include what outside resources you used to complete each of your answers, including other students, man pages, and web resources. You do not need to list help from the instructor, TA, or information found in the textbook.

	==Getting Started==		==Getting Started==

Soma: /* Questions */

2021-10-07T04:53:58Z

Questions

← Older revision		Revision as of 04:53, 7 October 2021
Line 32:		Line 32:
	# [2] How many processes does countdown.sh create, and how many executables does it run? How can you verify this using bpftrace?		# [2] How many processes does countdown.sh create, and how many executables does it run? How can you verify this using bpftrace?
	# [2] What is child_exited used for? Why is it needed?		# [2] What is child_exited used for? Why is it needed?
			# [2] How can you create a shell script that sends a SIGTERM signal to whatever process that ran it (its parent)? What happens when you run 3000capture on it?
			# [2] How can you verify that the shell script from the previous question is actually sending the right signal using bpftrace?
	# [4] How could you change 3000capture so that when it receives a SIGUSR1 signal it		# [4] How could you change 3000capture so that when it receives a SIGUSR1 signal it
	#* Prints "SIGUSR1 received, shutting down."		#* Prints "SIGUSR1 received, shutting down."

Soma: /* Questions */

2021-10-07T04:49:44Z

Questions

← Older revision		Revision as of 04:49, 7 October 2021
Line 32:		Line 32:
	# [2] How many processes does countdown.sh create, and how many executables does it run? How can you verify this using bpftrace?		# [2] How many processes does countdown.sh create, and how many executables does it run? How can you verify this using bpftrace?
	# [2] What is child_exited used for? Why is it needed?		# [2] What is child_exited used for? Why is it needed?
			# [4] How could you change 3000capture so that when it receives a SIGUSR1 signal it
			#* Prints "SIGUSR1 received, shutting down."
			#* Sends a SIGTERM signal to its child
			#* Waits one second
			#* If the child has terminated, it reports "Child successfully terminated with status %d" (with %d being the status)
			#* If the child has not terminated, it reports "Child still running, aborting." and exits with a return value of -10.

	==Code==		==Code==

Soma: /* Questions */

2021-10-07T04:43:27Z

Questions

← Older revision		Revision as of 04:43, 7 October 2021
Line 31:		Line 31:
	# [2] How could you fix 3000capture so it sends its output to the file specified by the CAPTURE environment variable? If there is no CAPTURE environment variable, it should use the same default as it does currently.		# [2] How could you fix 3000capture so it sends its output to the file specified by the CAPTURE environment variable? If there is no CAPTURE environment variable, it should use the same default as it does currently.
	# [2] How many processes does countdown.sh create, and how many executables does it run? How can you verify this using bpftrace?		# [2] How many processes does countdown.sh create, and how many executables does it run? How can you verify this using bpftrace?
			# [2] What is child_exited used for? Why is it needed?

	==Code==		==Code==

Soma: /* Questions */

2021-10-07T04:42:13Z

Questions

← Older revision		Revision as of 04:42, 7 October 2021
Line 27:		Line 27:

	# [2] If we read from /dev/null, what data do we get? How can you verify this?		# [2] If we read from /dev/null, what data do we get? How can you verify this?
	# [2] 3000capture requires commands to be		# [2] 3000capture requires commands to be fully qualified pathnames. How can you modify 3000capture so that if a command doesn't have a / in it, 3000capture searches the current PATH to find the right program? If PATH isn't defined it should search a default set of directories.
	# [2] What is the purpose of the fflush() call in parent() at line 36? Why isn't it needed elsewhere in parent()?		# [2] What is the purpose of the fflush() call in parent() at line 36? Why isn't it needed elsewhere in parent()?
	# [2] How could you fix 3000capture so it sends its output to the file specified by the CAPTURE environment variable? If there is no CAPTURE environment variable, it should use the same default as it does currently.		# [2] How could you fix 3000capture so it sends its output to the file specified by the CAPTURE environment variable? If there is no CAPTURE environment variable, it should use the same default as it does currently.
			# [2] How many processes does countdown.sh create, and how many executables does it run? How can you verify this using bpftrace?

	==Code==		==Code==