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Apache The Definitive Guide, 3rd EditionApache: The Definitive GuideSearch this book

2.6. Shared Objects

If you are using the DSO mechanism, you need quite a lot of stuff in your Config file.

2.6.1. Shared Objects Under Unix

In Apache v1.3 the order of these directives is important, so it is probably easiest to generate the list by doing an "out of the box" build using the flag --enable-shared=max. You will find /usr/etc/httpd/httpd.conf.default: copy the list from it into your own Config file, and edit it as you need.

LoadModule env_module         libexec/mod_env.so
LoadModule config_log_module  libexec/mod_log_config.so
LoadModule mime_module        libexec/mod_mime.so
LoadModule negotiation_module libexec/mod_negotiation.so
LoadModule status_module      libexec/mod_status.so
LoadModule includes_module    libexec/mod_include.so
LoadModule autoindex_module   libexec/mod_autoindex.so
LoadModule dir_module         libexec/mod_dir.so
LoadModule cgi_module         libexec/mod_cgi.so
LoadModule asis_module        libexec/mod_asis.so
LoadModule imap_module        libexec/mod_imap.so
LoadModule action_module      libexec/mod_actions.so
LoadModule userdir_module     libexec/mod_userdir.so
LoadModule alias_module       libexec/mod_alias.so
LoadModule access_module      libexec/mod_access.so
LoadModule auth_module        libexec/mod_auth.so
LoadModule setenvif_module    libexec/mod_setenvif.so

#  Reconstruction of the complete module list from all available modules
#  (static and shared ones) to achieve correct module execution order.
#  [WHENEVER YOU CHANGE THE LOADMODULE SECTION ABOVE UPDATE THIS, TOO]
ClearModuleList
AddModule mod_env.c
AddModule mod_log_config.c
AddModule mod_mime.c
AddModule mod_negotiation.c
AddModule mod_status.c
AddModule mod_include.c
AddModule mod_autoindex.c
AddModule mod_dir.c
AddModule mod_cgi.c
AddModule mod_asis.c
AddModule mod_imap.c
AddModule mod_actions.c
AddModule mod_userdir.c
AddModule mod_alias.c
AddModule mod_access.c
AddModule mod_auth.c
AddModule mod_so.c
AddModule mod_setenvif.c

Notice that the list comes in three parts: LoadModules, then ClearModuleList, followed by AddModules to activate the ones you want. As we said earlier, it is all rather cumbersome and easy to get wrong. You might want put the list in a separate file and then Include it (see later in this section). If you have left out a shared module that is required by a directive in your Config file, you will get a clear indication in an error message as Apache loads. For instance, if you use the directive ErrorLog without doing what is necessary for the module mod_log_config, this will trigger a runtime error message.

2.6.1.1. LoadModule

The LoadModule directive links in the object file or library filename and adds the module structure named module to the list of active modules.

LoadModule module filename
server config
mod_so 

module is the name of the external variable of type module in the file and is listed as the Module Identifier in the module documentation. For example (Unix, and for Windows as of Apache 1.3.15):

LoadModule status_module modules/mod_status.so 

For example (Windows prior to Apache 1.3.15, and some third party modules):

LoadModule foo_module modules/ApacheModuleFoo.dll

2.6.2. Shared Modules Under Win32

Note that all modules bundled with the Apache Win32 binary distribution were renamed as of Apache Version 1.3.15.

Win32 Apache modules are often distributed with the old style names, or even a name such as libfoo.dll. Whatever the name of the module, the LoadModule directive requires the exact filename.

2.6.2.1. LoadFile

The LoadFile directive links in the named object files or libraries when the server is started or restarted; this is used to load additional code that may be required for some modules to work.

LoadFile filename [filename] ...
server config
Mod_so

filename is either an absolute path or relative to ServerRoot.

2.6.2.2. ClearModuleList

This directive clears the list of active modules.

ClearModuleList
server config
 Abolished in Apache v2

It is assumed that the list will then be repopulated using the AddModule directive.

2.6.2.3. AddModule

The server can have modules compiled in that are not actively in use. This directive can be used to enable the use of those modules.

AddModule module [module] ...
server config 
Mod_so

The server comes with a preloaded list of active modules; this list can be cleared with the ClearModuleList directive.



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