Alcor... CGI programs


You may run CGI programs on Alcor. Please remember that you are held entirely responsible for the results of any CGI programs you install.

Users may run CGI programs on Alcor only through the intermediary of cgiwrap, a program which ensures that your programs run as your user ID, and thus have access only to those files your account can access.

To install and invoke your CGI program, you need to:

  1. Make a subdirectory called "cgi-bin" under your www subdirectory.

  2. Place your CGI scripts and programs in this cgi-bin subdirectory. (Your program may be a symbolic link to another executable, if you like.)

  3. Make sure your CGI scripts are executable by your own account; it is not necessary that they be readable or executable to anyone else, since they will run with your user ID.

  4. Make sure that all the programs and facilities used by your program are available under the chroot environment; check in /public/usr/bin and /public/local/paths. If you need a program that is not available, post a request to the newsgroup concordia.dept.iits.help (but please be aware that there's no guarantee that your request will be fulfilled).

  5. You may now invoke the program with the url:

    /cgi-bin/cgiwrap/~your_acct/yourscript

Some additional notes:

It is important to be aware of security issues surrounding CGI programs. By installing a CGI program in the web area of your account (i.e., in your www/cgi-bin directory), you are permitting anyone on the Internet to run that program on Alcor, with the privileges of your account. If you make (or the author of the script you install makes) a programming error which creates a security hole, anyone on the Internet may be able to execute arbitrary commands on Alcor (under the chroot), with the privileges of your account. You are responsible for such activities, so practice safe CGI programming.

Here are a few documents on CGI security:

If you know how to program, you can read the crash introduction to CGI called CGI Made Really Easy. A more complete reference on CGI programming is the CGI programming FAQ.

Finally, we have made available the CGI.pm perl module.


Copyright, © 2003, Concordia University, (IITS).
Author: Anne Bennett
Credits: (none)
Maintained by: webdoc@alcor.concordia.ca
Last update: 1998/06/19 -- Dana Echtner

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