Operating Systems 2017F: Tutorial 6 - Revision history

Soma at 21:35, 12 November 2017

2017-11-12T21:35:01Z

← Older revision		Revision as of 21:35, 12 November 2017
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	In this tutorial you will be running and modifying [http://homeostasis.scs.carleton.ca/~soma/os-2017f/code/lec16/newgetpid.zip newgetpid.c] from [[Operating Systems 2017F Lecture 16\|Lecture 16]]. You will likely want to look at the Linux kernel source, particularly [http://elixir.free-electrons.com/linux/v4.4.88/source/kernel/sys.c kernel/sys.c].		In this tutorial you will be running and modifying [http://homeostasis.scs.carleton.ca/~soma/os-2017f/code/lec16/newgetpid.zip newgetpid.c] from [[Operating Systems 2017F Lecture 16\|Lecture 16]]. You will likely want to look at the Linux kernel source, particularly [http://elixir.free-electrons.com/linux/v4.4.83/source/kernel/sys.c kernel/sys.c].

	==Tasks==		==Tasks==
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	#* Add a write method by adding a write operation to the file operations struct. Write operations have the same prototype as read operations, except the buffer is marked constant (because it shouldn't be modified).		#* Add a write method by adding a write operation to the file operations struct. Write operations have the same prototype as read operations, except the buffer is marked constant (because it shouldn't be modified).
	#* Convert the written text to an integer and store in a global variable (to the module).		#* Convert the written text to an integer and store in a global variable (to the module).
	#* Find the right task struct. See the implementation of the [http://elixir.free-electrons.com/linux/v4.4.88/source/kernel/signal.c#L2855 kill system call], and how it [http://elixir.free-electrons.com/linux/v4.4.88/source/kernel/signal.c#L1388 looks up the pid struct] and then [http://elixir.free-electrons.com/linux/v4.4.88/source/kernel/signal.c#L1303 gets the right task struct using that pid struct].		#* Find the right task struct. See the implementation of the [http://elixir.free-electrons.com/linux/v4.4.83/source/kernel/signal.c#L2855 kill system call], and how it [http://elixir.free-electrons.com/linux/v4.4.83/source/kernel/signal.c#L1388 looks up the pid struct] and then [http://elixir.free-electrons.com/linux/v4.4.83/source/kernel/signal.c#L1303 gets the right task struct using that pid struct].
	#* After returning info on the selected process, further calls should return info on the current process. You can do this by setting the global process ID to 0 and checking this value, using the current task if it is zero.		#* After returning info on the selected process, further calls should return info on the current process. You can do this by setting the global process ID to 0 and checking this value, using the current task if it is zero.

Soma: /* Tasks */

2017-11-12T21:32:03Z

Tasks

← Older revision		Revision as of 21:32, 12 November 2017
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	#* Add a write method by adding a write operation to the file operations struct. Write operations have the same prototype as read operations, except the buffer is marked constant (because it shouldn't be modified).		#* Add a write method by adding a write operation to the file operations struct. Write operations have the same prototype as read operations, except the buffer is marked constant (because it shouldn't be modified).
	#* Convert the written text to an integer and store in a global variable (to the module).		#* Convert the written text to an integer and store in a global variable (to the module).
	#* Find the right task struct. See the implementation of the[http://elixir.free-electrons.com/linux/v4.4.88/source/kernel/signal.c#L2855 kill system call], and how it [http://elixir.free-electrons.com/linux/v4.4.88/source/kernel/signal.c#L1388 looks up the pid struct] and then [http://elixir.free-electrons.com/linux/v4.4.88/source/kernel/signal.c#L1303 gets the right task struct using that pid struct].		#* Find the right task struct. See the implementation of the [http://elixir.free-electrons.com/linux/v4.4.88/source/kernel/signal.c#L2855 kill system call], and how it [http://elixir.free-electrons.com/linux/v4.4.88/source/kernel/signal.c#L1388 looks up the pid struct] and then [http://elixir.free-electrons.com/linux/v4.4.88/source/kernel/signal.c#L1303 gets the right task struct using that pid struct].
	#* After returning info on the selected process, further calls should return info on the current process. You can do this by setting the global process ID to 0 and checking this value, using the current task if it is zero.		#* After returning info on the selected process, further calls should return info on the current process. You can do this by setting the global process ID to 0 and checking this value, using the current task if it is zero.

Soma at 21:31, 12 November 2017

2017-11-12T21:31:49Z

← Older revision		Revision as of 21:31, 12 November 2017
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	# Make /dev/describe output the calling process's parent ID (ppid), user ID (uid), group ID (gid), effective user ID (euid), and effective group ID (egid).		# Make /dev/describe output the calling process's parent ID (ppid), user ID (uid), group ID (gid), effective user ID (euid), and effective group ID (egid).
	# '''(Advanced)''' Modify /dev/describe so that if you write a process ID to it, it will output the information on the provided process. To make this work, you'll need to:		# '''(Advanced)''' Modify /dev/describe so that if you write a process ID to it, it will output the information on the provided process. To make this work, you'll need to:
	## Find the right task struct ~~following~~ the implementation of the [http://elixir.free-electrons.com/linux/v4.4.88/source/kernel/signal.c#L2855 kill system call], and how it [http://elixir.free-electrons.com/linux/v4.4.88/source/kernel/signal.c#L1388 looks up the pid struct] and then [http://elixir.free-electrons.com/linux/v4.4.88/~~ident~~/~~kill_pid_info kill_pid_info() iterates through~~ the task ~~list~~].		#* Add a write method by adding a write operation to the file operations struct. Write operations have the same prototype as read operations, except the buffer is marked constant (because it shouldn't be modified).
			#* Convert the written text to an integer and store in a global variable (to the module).
			#* Find the right task struct. See the implementation of the[http://elixir.free-electrons.com/linux/v4.4.88/source/kernel/signal.c#L2855 kill system call], and how it [http://elixir.free-electrons.com/linux/v4.4.88/source/kernel/signal.c#L1388 looks up the pid struct] and then [http://elixir.free-electrons.com/linux/v4.4.88/source/kernel/signal.c#L1303 gets the right task struct using that pid struct].
			#* After returning info on the selected process, further calls should return info on the current process. You can do this by setting the global process ID to 0 and checking this value, using the current task if it is zero.

Soma at 21:21, 12 November 2017

2017-11-12T21:21:42Z

← Older revision		Revision as of 21:21, 12 November 2017
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	In this tutorial you will be running and modifying [http://homeostasis.scs.carleton.ca/~soma/os-2017f/code/lec16/newgetpid.zip newgetpid.c] from [[Operating Systems 2017F Lecture 16\|Lecture 16]].		In this tutorial you will be running and modifying [http://homeostasis.scs.carleton.ca/~soma/os-2017f/code/lec16/newgetpid.zip newgetpid.c] from [[Operating Systems 2017F Lecture 16\|Lecture 16]]. You will likely want to look at the Linux kernel source, particularly [http://elixir.free-electrons.com/linux/v4.4.88/source/kernel/sys.c kernel/sys.c].

			==Tasks==

			# Build and run newgetpid.c as demonstrated in Lecture 16 and as we did in the previous tutorial.
			# What type is "current"? How can you figure this out?
			# Modify newgetpid.c so that it creates a device file /dev/describe rather than /dev/newgetpid.
			# Make /dev/describe output the calling process's parent ID (ppid), user ID (uid), group ID (gid), effective user ID (euid), and effective group ID (egid).
			# '''(Advanced)''' Modify /dev/describe so that if you write a process ID to it, it will output the information on the provided process. To make this work, you'll need to:
			## Find the right task struct following the implementation of the [http://elixir.free-electrons.com/linux/v4.4.88/source/kernel/signal.c#L2855 kill system call], and how it [http://elixir.free-electrons.com/linux/v4.4.88/source/kernel/signal.c#L1388 looks up the pid struct] and then [http://elixir.free-electrons.com/linux/v4.4.88/ident/kill_pid_info kill_pid_info() iterates through the task list].

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2017-11-12T21:03:40Z

Created page with "In this tutorial you will be running and modifying [http://homeostasis.scs.carleton.ca/~soma/os-2017f/code/lec16/newgetpid.zip newgetpid.c] from Operating Systems 2017F Lect..."

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In this tutorial you will be running and modifying [http://homeostasis.scs.carleton.ca/~soma/os-2017f/code/lec16/newgetpid.zip newgetpid.c] from [[Operating Systems 2017F Lecture 16|Lecture 16]].