COM 1204 Object-Oriented Design - Summer 2001 - Electronic Handins

Professor Futrelle -- College of Computer Science, Northeastern U., Boston, MA

(Updated Monday 6/18/2001)


You should check your mail at least once a day or you may miss important course announcements.

Secure Unix directories: A simple strategy to keep your files secure is to create a unix directory which is executable, "x", but not readable, "r" and within it, typically in your webspace (your .www directory), you can prevent people from accessing even the most common files, e.g., index.html. But when you give us the full URL we can access your HTML and source code and executable files in these directories.

Below, I go through steps needed to create such a structure and place a file in the innermost directory, index.txt.

[denali: ~] > cd .www
[denali: ~/.www] > mkdir my-com1204
[denali: ~/.www] > cd  my-com1204
[denali: ~/.www/my-com1204] > mkdir secure1
[denali: ~/.www/my-com1204] > chmod  go-r secure1
[denali: ~/.www/my-com1204] > cd secure1
[denali: ~/.www/my-com1204/secure1] > mkdir  8ghbk5
[denali: ~/.www/my-com1204/secure1] > cd 8ghbk5/
[denali: ~/.www/my-com1204/secure1/8ghbk5] > cat > index.txt
This is a "hidden" file.
[denali: ~/.www/my-com1204/secure1/8ghbk5] > ls
[denali: ~/.www/my-com1204/secure1/8ghbk5] > ls -l
total 0
-rw-r--r--   1 futrelle faculty       23 Jun 12 04:51 index.txt
[denali: ~/.www/my-com1204/secure1/8ghbk5] > cd ../..
[denali: ~/.www/my-com1204] > cd ..
[denali: ~/.www] > ls -lR my-com1204/
total 8
drwx--x--x   3 futrelle faculty     4096 Jun 12 04:50 secure1/

total 8
drwxr-xr-x   2 futrelle faculty     4096 Jun 12 04:51 8ghbk5/

total 0
-rw-r--r--   1 futrelle faculty       23 Jun 12 04:51 index.txt
[denali: ~/.www] >

The above file can be accessed through the URL
but only a person who knows this full URL could ever access this file, since if they tried to get a directory listing for it, the missing read permission would block them.

If you want us to be able to compile and run your code in your inner directory, add write permission to the directory.

Your email Subject: lines must be in the following form, as an example:

J. Lando 012-99-3333 COM1204 Assignment 3

Your mail must contain a collection or URLs such as the one above, starting with "http:" and NOT ending with any punctuation. Or it can contain a single URL pointing to a web page your create that has the links. In either arrangement, by clicking on your URLs we can immediately see your work.

If you would rather keep your source and compiled files elsewhere, set up a secure directory there and send us its location in the following required form, as an example:

cd ~jlando/a2/7bhm3nj/

By pasting this command into our shell we can immediately go to that directory.

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