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Apache HTTP Server Version 2.0
Manual Page: apxs
NAME
apxs - APache eXtenSion tool
SYNOPSIS
apxs -g [ -S name=value ] -n modname
apxs -q [ -S name=value ] query ...
apxs -c [ -S name=value ] [ -o dsofile ] [ -I incdir ] [ -D
name=value ] [ -L libdir ] [ -l libname ] [ -Wc,compiler-
flags ] [ -Wl,linker-flags ] files ...
apxs -i [ -S name=value ] [ -n modname ] [ -a ] [ -A ] dso-
file ...
apxs -e [ -S name=value ] [ -n modname ] [ -a ] [ -A ] dso-
file ...
DESCRIPTION
apxs is a tool for building and installing extension modules
for the Apache HyperText Transfer Protocol (HTTP) server.
This is achieved by building a dynamic shared object (DSO)
from one or more source or object files which then can be
loaded into the Apache server under runtime via the LoadMo-
dule directive from mod_so.
So to use this extension mechanism your platform has to sup-
port the DSO feature and your Apache httpd binary has to be
built with the mod_so module. The apxs tool automatically
complains if this is not the case. You can check this your-
self by manually running the command
$ httpd -l
The module mod_so should be part of the displayed list. If
these requirements are fulfilled you can easily extend your
Apache server's functionality by installing your own modules
with the DSO mechanism by the help of this apxs tool:
$ apxs -i -a -c mod_foo.c
gcc -fpic -DSHARED_MODULE -I/path/to/apache/include -c mod_foo.c
ld -Bshareable -o mod_foo.so mod_foo.o
cp mod_foo.so /path/to/apache/modules/mod_foo.so
chmod 755 /path/to/apache/modules/mod_foo.so
[activating module `foo' in /path/to/apache/etc/httpd.conf]
$ apachectl restart
/path/to/apache/sbin/apachectl restart: httpd not running, trying to start
[Tue Mar 31 11:27:55 1998] [debug] mod_so.c(303): loaded module foo_module
/path/to/apache/sbin/apachectl restart: httpd started
$ _
The arguments files can be any C source file (.c), a object
file (.o) or even a library archive (.a). The apxs tool
automatically recognizes these extensions and automatically
used the C source files for compilation while just using the
object and archive files for the linking phase. But when
using such pre-compiled objects make sure they are compiled
for position independent code (PIC) to be able to use them
for a dynamically loaded shared object. For instance with
GCC you always just have to use -fpic. For other C com-
pilers consult its manual page or at watch for the flags
apxs uses to compile the object files.
For more details about DSO support in Apache read the docu-
mentation of mod_so or perhaps even read the
src/modules/standard/mod_so.c source file.
OPTIONS
Common options:
-n modname This explicitly sets the module name for the -i
(install) and -g (template generation) option.
Use this to explicitly specify the module name.
For option -g this is required, for option -i
the apxs tool tries to determine the name from
the source or (as a fallback) at least by guess-
ing it from the filename.
Query options:
-q Performs a query for apxs's knowledge about cer-
tain settings. The query parameters can be one
or more of the following strings:
CC TARGET
CFLAGS SBINDIR
CFLAGS_SHLIB INCLUDEDIR
LD_SHLIB LIBEXECDIR
LDFLAGS_SHLIB SYSCONFDIR
LIBS_SHLIB
Use this for manually determining settings. For
instance use
INC=-I`apxs -q INCLUDEDIR`
inside your own Makefiles if you need manual
access to Apache's C header files.
Configuration options:
-S name=value
This option changes the apxs settings described
above.
Template Generation options:
-g This generates a subdirectory name (see option
-n) and there two files: A sample module source
file named mod_name.c which can be used as a
template for creating your own modules or as a
quick start for playing with the APXS mechanism.
And a corresponding Makefile for even easier
build and installing of this module.
DSO compilation options:
-c This indicates the compilation operation. It
first compiles the C source files (.c) of files
into corresponding object files (.o) and then
builds a dynamically shared object in dsofile by
linking these object files plus the remaining
object files (.o and .a) of files If no -o
option is specified the output file is guessed
from the first filename in files and thus usu-
ally defaults to mod_name.so
-o dsofile Explicitly specifies the filename of the created
dynamically shared object. If not specified and
the name cannot be guessed from the files list,
the fallback name mod_unknown.so is used.
-D name=value
This option is directly passed through to the
compilation command(s). Use this to add your
own defines to the build process.
-I incdir This option is directly passed through to the
compilation command(s). Use this to add your
own include directories to search to the build
process.
-L libdir This option is directly passed through to the
linker command. Use this to add your own
library directories to search to the build pro-
cess.
-l libname This option is directly passed through to the
linker command. Use this to add your own
libraries to search to the build process.
-Wc,compiler-flags
This option passes compiler-flags as additional
flags to the compiler command. Use this to add
local compiler-specific options.
-Wl,linker-flags
This option passes linker-flags as additional
flags to the linker command. Use this to add
local linker-specific options.
DSO installation and configuration options:
-i This indicates the installation operation and
installs one or more dynamically shared objects
into the server's modules directory.
-a This activates the module by automatically
adding a corresponding LoadModule line to
Apache's httpd.conf configuration file, or by
enabling it if it already exists.
-A Same as option -a but the created LoadModule
directive is prefixed with a hash sign (#), i.e.
the module is just prepared for later activation
but initially disabled.
-e This indicates the editing operation, which can
be used with the -a and -A options similarly to
the -i operation to edit Apache's httpd.conf
configuration file without attempting to install
the module.
EXAMPLES
Assume you have an Apache module named mod_foo.c available
which should extend Apache's server functionality. To accom-
plish this you first have to compile the C source into a
shared object suitable for loading into the Apache server
under runtime via the following command:
$ apxs -c mod_foo.c
gcc -fpic -DSHARED_MODULE -I/path/to/apache/include -c mod_foo.c
ld -Bshareable -o mod_foo.so mod_foo.o
$ _
Then you have to update the Apache configuration by making
sure a LoadModule directive is present to load this shared
object. To simplify this step apxs provides an automatic way
to install the shared object in its "modules" directory and
updating the httpd.conf file accordingly. This can be
achieved by running:
$ apxs -i -a mod_foo.c
cp mod_foo.so /path/to/apache/modules/mod_foo.so
chmod 755 /path/to/apache/modules/mod_foo.so
[activating module `foo' in /path/to/apache/etc/httpd.conf]
$ _
This way a line named
LoadModule foo_module modules/mod_foo.so
is added to the configuration file if still not present. If
you want to have this disabled per default use the -A
option, i.e.
$ apxs -i -A mod_foo.c
For a quick test of the APXS mechanism you can create a sam-
ple Apache module template plus a corresponding Makefile
via:
$ apxs -g -n foo
Creating [DIR] foo
Creating [FILE] foo/Makefile
Creating [FILE] foo/mod_foo.c
$ _
Then you can immediately compile this sample module into a
shared object and load it into the Apache server:
$ cd foo
$ make all reload
apxs -c mod_foo.c
gcc -fpic -DSHARED_MODULE -I/path/to/apache/include -c mod_foo.c
ld -Bshareable -o mod_foo.so mod_foo.o
apxs -i -a -n "foo" mod_foo.so
cp mod_foo.so /path/to/apache/modules/mod_foo.so
chmod 755 /path/to/apache/modules/mod_foo.so
[activating module `foo' in /path/to/apache/etc/httpd.conf]
apachectl restart
/path/to/apache/sbin/apachectl restart: httpd not running, trying to start
[Tue Mar 31 11:27:55 1998] [debug] mod_so.c(303): loaded module foo_module
/path/to/apache/sbin/apachectl restart: httpd started
$ _
You can even use apxs to compile complex modules outside the
Apache source tree, like PHP3:
$ cd php3
$ ./configure --with-shared-apache=../apache-1.3
$ apxs -c -o libphp3.so mod_php3.c libmodphp3-so.a
gcc -fpic -DSHARED_MODULE -I/tmp/apache/include -c mod_php3.c
ld -Bshareable -o libphp3.so mod_php3.o libmodphp3-so.a
$ _
because apxs automatically recognized C source files and
object files. Only C source files are compiled while
remaining object files are used for the linking phase.
SEE ALSO
apachectl(1), httpd(8).
Apache HTTP Server Version 2.0
