CSCI A348/548 Lecture Notes Four Fall 2000

You may already have a web server, installed following the notes from the first lecture, with a welcome page. We have installed the web server, made the necessary changes to the configuration files and started the web server. Today we want to revisit installation and configuration of Apache because we want to make sure all is very clear. We also review the issues related to starting and stopping the server and introduce a way to start the server automatically (if necessary) to protect it from system reboots. This also counts as a Unix review, to a certain extent.

1. Announcements

You are encouraged to work on assignments together, you'll get to know each other so that you can work on the projects in teams. Also make sure you know of and make good use of the class newsgroup, located at: ac.csci.a348

2. Installation of Apache

Apache should be installed in your directory and the relevant directory structure should be like this:

/u/username/httpd/                    # directory 
/u/username/httpd/httpd               # file 
                 /conf/               # directory
                 /conf/httpd.conf     # file 
                      /srm.conf       # file 
                      /access_conf    # file 
                 /htdocs/             # directory
                 /htdocs/index.html   # file 
                 /cgi-bin/            # directory 
                 /logs/               # directory
                 /logs/access_log     # file 
                 /logs/error_log      # file 
                 /logs/httpd.pid      # file 

Here's a quick description of these files and directories.

/u/username/httpd/

This is the ServerRoot directory.

This file is the actual web server. You need to restart your server every time you make a change to one of your configuration files.

This directory contains configuration files.

This is the server's main configuration file.

This is the server resource configuration file.

This is the global access control file.

This is the DocumentRoot directory.

This is the server's welcome page.

This is the CGI scripts directory.

This directory contains log files.

The accesses to your site are logged here.

The server logs here any errors that hit has to report.

This file contains the process id of the server.

In what follows please use your username instead of dgerman, and your port number for 10000. The file below is the one for the following assignment:

• username - dgerman
• port assigned - 10000

burrowww.cs.indiana.edu% diff httpd.conf httpd.conf-dist
32c32
< Port 10000
---
> Port 80
52c52
< User dgerman
---
> User nobody
58c58
< ServerAdmin dgerman@indiana.edu
---
> ServerAdmin you@your.address
66c66
< ServerRoot /u/dgerman/httpd  
---
> ServerRoot @@ServerRoot@@
127c127
< LockFile /tmp/apache.lockfile.dgerman
---
> #LockFile logs/accept.lock
185,186c185,186
< MinSpareServers 1  
< MaxSpareServers 3 
---
> MinSpareServers 5
> MaxSpareServers 10
190c190
< StartServers 1 
---
> StartServers 5
burrowww.cs.indiana.edu% 

So we change:

• Port
• User
• ServerAdmin
• ServerRoot
• LockFile
• MinSpareServers
MaxSpareServers
• StartServers

Please use your username instead of dgerman.

burrowww.cs.indiana.edu% diff srm.conf srm.conf-dist  
15c15
< DocumentRoot /u/dgerman/httpd/htdocs
---
> DocumentRoot @@ServerRoot@@/htdocs
20c20
< UserDir httpd/htdocs  
---
> UserDir public_html
143c143
< Alias /icons/ /u/dgerman/httpd/icons/
---
> Alias /icons/ @@ServerRoot@@/icons/
148c148
< ScriptAlias /cgi-bin/ /u/dgerman/httpd/cgi-bin/
---
> #ScriptAlias /cgi-bin/ @@ServerRoot@@/cgi-bin/
burrowww.cs.indiana.edu% 

• DocumentRoot
• UserDir
• Alias /icons/
• ScriptAlias /cgi-bin/

Please use your username instead of dgerman.

burrowww.cs.indiana.edu% diff access.conf access.conf-dist
28c28
< <Directory /u/dgerman/httpd/htdocs>
---
> <Directory @@ServerRoot@@/htdocs>
54c54
< <Directory /u/dgerman/httpd/cgi-bin>
---
> <Directory @@ServerRoot@@/cgi-bin>
burrowww.cs.indiana.edu%

• the document root, and
• the cgi-bin directory.

If your server is not running already you need to login into burrowww and type the following command:

/u/dgerman/httpd/httpd -d /u/dgerman/httpd

If your server is already running you won't be able to start the server with the command above. See restarting the server below.

To check if your server is running or not use:

/usr/bin/ps -ef | grep httpd | grep username

5. Stopping the server

This can be done with:

kill -TERM `cat /u/username/httpd/logs/httpd.pid`

If the file does not exist you should find the pid of the server (as described before) and use

kill -TERM pid

6. Restarting the server

kill -HUP `cat /u/username/httpd/logs/httpd.pid`

8. Log files

Significant events, such as starting, stopping, restarting, and errors in general are recorded in

@@ServerRoot@@/logs/error.log

@@ServerRoot@@/logs/access.log contains a log of all calls to your server.

7. Protecting the server from machine reboots

Use starthttpd (written by Steve Kinzler) to start and stop the server.

Copy it into your bin directory:

cp /u/dgerman/bin/starthttpd /u/username/bin/starthttpd-template
cp /u/username/bin/starthttpd-template /u/username/bin/starthttpd

Then use the editor of your choice to change the script for your account such that the differences are like this:

burrowww.cs.indiana.edu% diff starthttpd starthttpd-template
11c11
< basecmd="/u/dgerman/httpd/httpd -d $httpd"
---
> basecmd="/u/username/httpd/httpd -d $httpd"
burrowww.cs.indiana.edu%

burrowww.cs.indiana.edu% crontab -e
burrowww.cs.indiana.edu% crontab -l
0 6 * * * /u/dgerman/bin/starthttpd 
burrowww.cs.indiana.edu%

#!/usr/bin/perl

open(AB, $ARGV[0]); 
while ($x = <AB>) {
  print "Read: ", $x; 
  ($uname, $pword) = split(/:/, $x); 
  chop($pword); 
  $pairs{$uname} = $pword; 
}
close(AB); 

@m = keys %pairs; 
foreach $k (@m) {
   print $k, "\n"; 
} 

while ($user = <STDIN>) {
  chop($user); 
  if ($user =~ /^quit$/i) { exit; } 
  print "(", $user, ")\n";
  if ($pairs{$user}) {
    print "Yes, ", $user, " appears in the list.\n";
  } else {
    print "No, I don't see ", $user, "\n"; 
  } 
}