ajain13 / Character-Device

A kernel level pipe, as a miscellaneous character device, to exchange strings between user level processes. This is a classical producer consumer problem. The device maintains a FIFO queue that can contain a configurable number of strings. Several concurrent user level processes can read and write to the character device.

TEAMMATES DETAILS:

1. NAME : ABHISHEK JAIN
2. Name : PRADYUMNA KAUSHIK

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FILES INCLUDED IN THE TARBALL (excluding README):

1. Kernel-module code :  my_device_driver.c
				- Character device.

2. User-space code    :  my_producer.c
				- User-space code to infinitely write string (take from command line) to the character device.
			
			 my_consumer.c
				- User-space code to infinitely read string (length taken from command line) from the character device.


3. Compilation files  :  Makefile
				- Compiles Kernel-module code and the User-space code.

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KERNEL VERSION USED :

LINUX KERNEL 4.4.3

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COMPILATION AND EXECUTION INSTRUCTIONS: 1. Compilation : Type the following command,

			make

			-ignoring the warnings
	
2. Inserting module : Type the following command,
	
			sudo insmod my_device_driver.ko buffer_size=<size> device_name=my_misc_device string_char_count=<length of string>

			-buffer_size : size (number of strings) of buffer.
			-device_name : name of character device.
			-string_char_count : length of string in buffer.

3. Execute producer and consumer : Type the following commands on as many different terminals as needed,
			
			sudo ./my_producer.o <string> <length of string>
			sudo ./my_consumer.o <number of characters to read>

4. To stop execution : Type <Ctrl-C>

5. Remove module : Type the following command,

			sudo rmmod my_device_driver

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REFERENCES :

1. https://www.google.com/search?q=module_param&oq=module_param+&aqs=chrome..69i57j69i59j0l4.5935j0j7&sourceid=chrome&es_sm=122&ie=UTF-8

2. http://www.tldp.org/LDP/lkmpg/2.6/html/x323.html

3. http://www.makelinux.net/ldd3/chp-2-sect-8

4. http://www.makelinux.net/books/lkd2/ch16lev1sec6

5. https://www.fsl.cs.sunysb.edu/kernel-api/re256.html

6. https://www.fsl.cs.sunysb.edu/kernel-api/ch05s03.html

7. http://stackoverflow.com/questions/23433936/return-value-of-copy-from-user

8. http://www.makelinux.net/ldd3/chp-5-sect-3

9. http://lxr.free-electrons.com/ident?i=down_interruptible

10. http://comments.gmane.org/gmane.linux.kernel.kernelnewbies/45479

11. http://stackoverflow.com/questions/13291353/iso-c90-forbids-mixed-declarations-and-code-in-c

12. http://stackoverflow.com/questions/26678924/why-is-there-an-incompatible-pointer-type-warning

13. https://www.freebsd.org/cgi/man.cgi?query=kthread&sektion=9

14. http://www.thegeekstuff.com/2012/05/c-mutex-examples/

15. http://stackoverflow.com/questions/5558921/concurrency-a-monitor-that-implements-semaphores

16. http://www.thegeekstuff.com/2013/07/write-linux-kernel-module/

17. http://www.nxp.com/files/32bit/doc/app_note/AN2744.pdf?fsrch=1

18. http://tuxthink.blogspot.com/2011/02/kernel-thread-creation-1.html

19. http://stackoverflow.com/questions/5280693/kernel-thread-implementation

20. http://stackoverflow.com/questions/27581747/pthread-vs-kthread-in-linux-kernel-v2-6

21. http://forums.fedoraforum.org/showthread.php?t=157804

22. http://www.makelinux.net/books/lkd2/ch16lev1sec6

23. http://www.tldp.org/LDP/lkmpg/2.6/html/x323.html

24. https://www.google.com/search?q=module_param+for+char*&oq=module_param+for+char*&aqs=chrome..69i57j0l3.4174j0j7&sourceid=chrome&es_sm=122&ie=UTF-8

25. http://www.makelinux.net/books/lkd2/ch18lev1sec3

26. https://www.kernel.org/doc/htmldocs/kernel-api/API-misc-register.html

27. http://www.cs.binghamton.edu/~kartik/cs550/slides/kernel_modules.pdf

28. http://www.cs.binghamton.edu/~kartik/cs550/hw3.html

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