CS 180 - Assignment #5

This assignment is not difficult (they never are), but there are a lot of things going on here. If you want things to go smoothly, I highly recommend that you create a makefile for this project. There are several files that need to be built, and if you insist on doing it the hard way, one-at-a-time by-hand, you will most certainly get confused. The 10 minutes or so that you spend creating the makefile will pay-off in a very short time.

Information

• Handout
• memmgr.h (Text) This is the interface.
• driver-sample-s.c (Text) This is a sample driver to help you get started testing. (Static linking, not shared objects.) This driver is just to be used to get your memory manager working. I will be grading your assignment using the shared object version below.
• Command line to compile the program (statically-linked):

  gcc -O -g -Wall -Wextra -Werror -ansi -pedantic driver-sample-s.c memmgr.c -o memmgr
  

• To run the program, type this at the command line:

  ./memmgr X Y
  

  where X is the test number to run and Y is the value for the policy used to find an available block of memory. A value of 0 means first-fit and a value of 1 (or any non-zero value) means best-fit. The default is to run all tests using the first-fit policy. This flag only applies to the last 4 tests. See the driver for details.

  To detect memory errors and leaks, run it under valgrind like this:

  valgrind -q --leak-check=full --show-reachable=yes --tool=memcheck ./memmgr X Y
  

  replace X with the test number to run and Y with the policy.

• Refer to the diagrams from the Memory lecture for a refresher.

• Sample outputs:
  1. test_alloc1 (diagram, source)
  2. test_alloc2 (diagram, source)
  3. test_alloc3 (diagram, source)
  4. test_alloc4 (diagram, source)
  5. test_alloc5 (diagram, source)
  6. test_alloc6 (diagram, source)

  7. test_dealloc1 (diagram, source)
  8. test_dealloc2 (diagram, source)
  9. test_dealloc3 (diagram, source)
  10. test_dealloc4 (diagram, source)
  11. test_dealloc5 (diagram, source)

  12. test_ada1ff (first-fit)
  13. test_ada1bf (best-fit)
  14. test_ada2ff (first-fit)
  15. test_ada2bf (best-fit)

  16. All tests (first-fit)
  17. All tests (best-fit)

• Sample stress driver #1   HTML   Text

• Sample stress driver #2   HTML   Text

• Sample stress outputs:
1. Stress1 (first-fit)
   
2. Stress1 (first-fit, verbose)
   
3. Stress1 (best-fit)
   
4. Stress1 (best-fit, verbose)
   
5. Stress2 (first-fit)
   
6. Stress2 (best-fit)
   
• Using the dot tool from the Graphviz package:

dot -T graphic-type -o output-file input-file

For example, assume you have the graph definition in a text file named graph.txt and you want to create a PNG file called graph.png. This is the command:

dot -T png -o graph.png graph.txt

Shared Library

• Command lines to compile and link your memory manager into a shared library:

  gcc -O -g -Wall -Wextra -Werror -ansi -pedantic -fPIC -c memmgr.c -o memmgr.o
  gcc -shared memmgr.o -o libmemmgr.so
  

• shared.h (Text) This is some helper stuff. You need to implement two functions: load_library and get_functions that are prototyped in the header file.
• Command line to compile the shared.c code:

  gcc -O -g -Wall -Wextra -Werror -ansi -pedantic -c shared.c -o shared.o
  

  A note about the dlsym library function: Because the dlsym function can return NULL as a valid value of a requested symbol, it is not always safe to assume that a NULL value being returned is an indication of an error. However, for our purposes (and with the way we're implementing things), a NULL value will indicate an error condition. So, if the return from dlsym is NULL, you will return FAILURE immediately. (DO NOT call dlerror as that will mess things up when the driver calls it.)

• driver-sample-d.c (Text) This is a sample driver that expects shared objects.
• Command line to compile and link the driver with the shared library:

  gcc -O -g -Wall -Wextra -ansi -pedantic -Werror driver-sample-d.c shared.o -o memmgr-d -ldl
  

  Be aware that I will be running/grading your assignment based on the shared object version. The static version above was just for you to get a working memory manager. So, if you got the static version working, but not the shared object version, you will receive a failing grade for the assignment.

• Using script

You need to capture your shell session that shows various things like compiling and running the program, using diff to make sure your output is correct and running with valgrind and then running Doxygen. After you've finished coding and testing everything and are sure everything is correct, use the script command to make a text file of your session. From the bash shell in the directory you've setup to test with, run these commands: (You'll need a proper Doxygen config file called Doxyfile for the doxygen command to work.)

script
date
uptime
echo FIRSTNAME LASTNAME
pwd
whoami
uname -a
cat /proc/cpuinfo
cat /proc/meminfo
gcc -O -g -Wall -Wextra -Werror -ansi -pedantic -fPIC -c memmgr.c -o memmgr.o
gcc -shared memmgr.o -o libmemmgr.so
gcc -O -g -Wall -Wextra -Werror -ansi -pedantic -c shared.c -o shared.o
gcc -O -g -Wall -Wextra -ansi -pedantic -Werror driver-sample-d.c shared.o -o memmgr-d -ldl
./memmgr-d 2 0 | tee output.txt
diff --strip-trailing-cr output.txt output-alloc2.txt
valgrind -q --leak-check=full --show-reachable=yes --tool=memcheck ./memmgr > /dev/null
doxygen
ls -al html/

Then, press Ctrl-D to end the script session. A file named typescript was created with all of the commands and output. Replace FIRSTNAME and LASTNAME with your real first name and last name. This is how you get your name in the typescript file. Consult the man pages if you want more information on script.