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This tutorial describes how you can install Apache2 with mod_fcgid and PHP5 on Fedora 13. mod_fcgid is a compatible alternative to the older mod_fastcgi. It lets you execute PHP scripts with the permissions of their owners instead of the Apache user.

1 Preliminary Note

I'm using a Fedora 13 server in this tutorial with the hostname server1.example.com and the IP address 192.168.0.100.

I will create two Apache vhosts in this tutorial, www.example1.com and www.example2.com, to demonstrate the usage of mod_fcgid.

Before we start, make sure that SELinux is disabled. Open /etc/selinux/config...

vi /etc/selinux/config

... and set SELINUX to disabled:

# This file controls the state of SELinux on the system.
# SELINUX= can take one of these three values:
#     enforcing - SELinux security policy is enforced.
#     permissive - SELinux prints warnings instead of enforcing.
#     disabled - No SELinux policy is loaded.
SELINUX=disabled
# SELINUXTYPE= can take one of these two values:
#     targeted - Targeted processes are protected,
#     mls - Multi Level Security protection.
SELINUXTYPE=targeted

Run

setenforce 0

... for the change to take effect.

2 Installing Apache2/mod_fcgi/PHP5

We can install Apache2, mod_fcgid, and PHP5 as follows:

yum install httpd mod_fcgid php-cli

If Apache2 was already installed with PHP5 as an Apache module, disable the PHP5 module now - open /etc/httpd/conf.d/php.conf...

vi /etc/httpd/conf.d/php.conf

... and comment out everything in that file:

#
# PHP is an HTML-embedded scripting language which attempts to make it
# easy for developers to write dynamically generated webpages.
#
#<IfModule prefork.c>
#  LoadModule php5_module modules/libphp5.so
#</IfModule>
#<IfModule worker.c>
#  LoadModule php5_module modules/libphp5-zts.so
#</IfModule>
#
# Cause the PHP interpreter to handle files with a .php extension.
#
#AddHandler php5-script .php
#AddType text/html .php
#
# Add index.php to the list of files that will be served as directory
# indexes.
#
#DirectoryIndex index.php
#
# Uncomment the following line to allow PHP to pretty-print .phps
# files as PHP source code:
#
#AddType application/x-httpd-php-source .phps

Then we create the system startup links for Apache and start it:

chkconfig --levels 235 httpd on
/etc/init.d/httpd restart

Next we open /etc/php.ini...

vi /etc/php.ini

... and uncomment the line cgi.fix_pathinfo = 1:

[...]
; cgi.fix_pathinfo provides *real* PATH_INFO/PATH_TRANSLATED support for CGI.  PHP's
; previous behaviour was to set PATH_TRANSLATED to SCRIPT_FILENAME, and to not grok
; what PATH_INFO is.  For more information on PATH_INFO, see the cgi specs.  Setting
; this to 1 will cause PHP CGI to fix its paths to conform to the spec.  A setting
; of zero causes PHP to behave as before.  Default is 1.  You should fix your scripts
; to use SCRIPT_FILENAME rather than PATH_TRANSLATED.
; http://www.php.net/manual/en/ini.core.php#ini.cgi.fix-pathinfo
cgi.fix_pathinfo=1
[...]

Open /etc/httpd/conf.d/fcgid.conf...

vi /etc/httpd/conf.d/fcgid.conf

... and add the line PHP_Fix_Pathinfo_Enable 1 (unlike in previous Fedora versions, on 13 this line must not go into a <VirtualHost> section because then you would get this error: PHP_Fix_Pathinfo_Enable cannot occur within <VirtualHost> section):

# This is the Apache server configuration file for providing FastCGI support
# through mod_fcgid
#
# Documentation is available at
# http://httpd.apache.org/mod_fcgid/mod/mod_fcgid.html
LoadModule fcgid_module modules/mod_fcgid.so
# Use FastCGI to process .fcg .fcgi & .fpl scripts
AddHandler fcgid-script fcg fcgi fpl
# Sane place to put sockets and shared memory file
FcgidIPCDir /var/run/mod_fcgid
FcgidProcessTableFile /var/run/mod_fcgid/fcgid_shm
PHP_Fix_Pathinfo_Enable 1

Then reload Apache:

/etc/init.d/httpd reload

3 Creating Vhosts For www.example1.com And www.example2.com

I will now create two vhosts, www.example1.com (with the document root /var/www/web1/web) and www.example2.com (with the document root/var/www/web2/web). www.example1.com will be owned by the user and group web1, and www.example2.com by the user and group web2.

First we create the users and groups:

groupadd web1
groupadd web2
useradd -s /bin/false -d /var/www/web1 -m -g web1 web1
useradd -s /bin/false -d /var/www/web2 -m -g web2 web2
chmod 755 /var/www/web1
chmod 755 /var/www/web2

Then we create the document roots and make them owned by the users/groups web1 resp. web2:

mkdir -p /var/www/web1/web
chown web1:web1 /var/www/web1/web
mkdir -p /var/www/web2/web
chown web2:web2 /var/www/web2/web

We will run PHP using suExec; suExec's document root is /var/www, as the following command shows:

/usr/sbin/suexec -V

[root@server1 ~]# /usr/sbin/suexec -V
 -D AP_DOC_ROOT="/var/www"
 -D AP_GID_MIN=100
 -D AP_HTTPD_USER="apache"
 -D AP_LOG_EXEC="/var/log/httpd/suexec.log"
 -D AP_SAFE_PATH="/usr/local/bin:/usr/bin:/bin"
 -D AP_UID_MIN=500
 -D AP_USERDIR_SUFFIX="public_html"
[root@server1 ~]#

Therefore we cannot call the PHP binary (/usr/bin/php-cgi) directly because it is located outside suExec's document root. As suExec does not allow symlinks, the only way to solve the problem is to create a wrapper script for each web site in a subdirectory of /var/www; the wrapper script will then call the PHP binary/usr/bin/php-cgi. The wrapper script must be owned by the user and group of each web site, therefore we need one wrapper script for each web site. I'm going to create the wrapper scripts in subdirectories of /var/www/php-fcgi-scripts, e.g. /var/www/php-fcgi-scripts/web1 and /var/www/php-fcgi-scripts/web2.

mkdir -p /var/www/php-fcgi-scripts/web1
mkdir -p /var/www/php-fcgi-scripts/web2

vi /var/www/php-fcgi-scripts/web1/php-fcgi-starter

#!/bin/sh
PHPRC=/etc/
export PHPRC
export PHP_FCGI_MAX_REQUESTS=5000
export PHP_FCGI_CHILDREN=8
exec /usr/bin/php-cgi

vi /var/www/php-fcgi-scripts/web2/php-fcgi-starter

#!/bin/sh
PHPRC=/etc/
export PHPRC
export PHP_FCGI_MAX_REQUESTS=5000
export PHP_FCGI_CHILDREN=8
exec /usr/bin/php-cgi

The PHPRC line contains the directory where the php.ini file is located (i.e., /etc/ translates to /etc/php.ini). PHP_FCGI_MAX_REQUESTS is the maximum number of requests before an fcgid process is stopped and a new one is launched. PHP_FCGI_CHILDREN defines the number of PHP children that will be launched.

The php-fcgi-starter scripts must be executable, and they (and the directories they are in) must be owned by the web site's user and group:

chmod 755 /var/www/php-fcgi-scripts/web1/php-fcgi-starter
chmod 755 /var/www/php-fcgi-scripts/web2/php-fcgi-starter
chown -R web1:web1 /var/www/php-fcgi-scripts/web1
chown -R web2:web2 /var/www/php-fcgi-scripts/web2

Now we create the Apache vhosts for www.example1.com and www.example2.com. Add the following two vhosts at the end of /etc/httpd/conf/httpd.conf:

vi /etc/httpd/conf/httpd.conf

[...]
NameVirtualHost *:80
<VirtualHost *:80>
  ServerName www.example1.com
  ServerAlias example1.com
  ServerAdmin webmaster@example1.com
  DocumentRoot /var/www/web1/web/
  <IfModule mod_fcgid.c>
    SuexecUserGroup web1 web1
    <Directory /var/www/web1/web/>
      Options +ExecCGI
      AllowOverride All
      AddHandler fcgid-script .php
      FCGIWrapper /var/www/php-fcgi-scripts/web1/php-fcgi-starter .php
      Order allow,deny
      Allow from all
    </Directory>
  </IfModule>
  # ErrorLog /var/log/apache2/error.log
  # CustomLog /var/log/apache2/access.log combined
  ServerSignature Off
</VirtualHost>
<VirtualHost *:80>
  ServerName www.example2.com
  ServerAlias example2.com
  ServerAdmin webmaster@example2.com
  DocumentRoot /var/www/web2/web/
  <IfModule mod_fcgid.c>
    SuexecUserGroup web2 web2
    <Directory /var/www/web2/web/>
      Options +ExecCGI
      AllowOverride All
      AddHandler fcgid-script .php
      FCGIWrapper /var/www/php-fcgi-scripts/web2/php-fcgi-starter .php
      Order allow,deny
      Allow from all
    </Directory>
  </IfModule>
  # ErrorLog /var/log/apache2/error.log
  # CustomLog /var/log/apache2/access.log combined
  ServerSignature Off
</VirtualHost>

Make sure you fill in the right paths (and the correct user and group in the SuexecUserGroup lines).

Reload Apache afterwards:

/etc/init.d/httpd reload

4 Testing

Now we create a small PHP test file, for example in the www.example1.com web site...

vi /var/www/web1/web/info.php

<?php
phpinfo();
?>

... and call that file in a browser (http://www.example1.com/info.php). If all goes well, the output should look similar to this, and you should see CGI/FastCGI in the Server API line:

5 Custom php.ini for Each Web Site

Because each web site has its own php-fcgi-starter wrapper script, it is possible to define different php.ini files for different web sites. To demonstrate this, I will copy the default php.ini (/etc/php.ini) to the /var/www/web2/ directory and make www.example2.com use the php.ini from the /var/www/web2/ directory:

cp /etc/php.ini /var/www/web2/
chown web2:web2 /var/www/web2/php.ini

(You can now modify /var/www/web2/php.ini to your likings.)

Then we open /var/www/php-fcgi-scripts/web2/php-fcgi-starter...

vi /var/www/php-fcgi-scripts/web2/php-fcgi-starter

... and put /var/www/web2/ in the PHPRC line:

#!/bin/sh
PHPRC=/var/www/web2/
export PHPRC
export PHP_FCGI_MAX_REQUESTS=5000
export PHP_FCGI_CHILDREN=8
exec /usr/bin/php-cgi

Reload Apache afterwards:

/etc/init.d/httpd reload

Create a new phpinfo(); file for www.example2.com...

vi /var/www/web2/web/info.php

<?php
phpinfo();
?>

... and call it in a browser (http://www.example2.com/info.php). The Loaded Configuration File line should now show /var/www/web2/php.ini:

6 Changing Single PHP Configuration Settings

Instead of passing a whole new php.ini file to your web site, you can as well change single PHP configuration settings in the php-fcgi-starter wrapper script (or use a combination of both) by adding the -d switch to the PHP executable. For example, if I want to disable magic_quotes_gpc for the web sitewww.example2.com, I'd do it as follows:

vi /var/www/php-fcgi-scripts/web2/php-fcgi-starter

#!/bin/sh
PHPRC=/etc/
export PHPRC
export PHP_FCGI_MAX_REQUESTS=5000
export PHP_FCGI_CHILDREN=8
exec /usr/bin/php-cgi -d magic_quotes_gpc=off

Reload Apache afterwards:

/etc/init.d/httpd reload

Then call the info.php script again in a browser (http://www.example2.com/info.php) and search for the magic_quotes_gpc line - it should show Off now:

7 Links

• mod_fcgid: http://fastcgi.coremail.cn/
• Apache: http://httpd.apache.org/
• PHP: http://www.php.net/
• Fedora: http://fedoraproject.org/