APXS(8)apxsAPXS(8)NAMEapxs - APache eXtenSion tool
SYNOPSISapxs-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,com-
piler-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 ...
SUMMARYapxs is a tool for building and installing extension mod-
ules 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 LoadModule directive from mod_so.
So to use this extension mechanism your platform has to
support the DSO feature and your Apache httpd binary has
to be built with the mod_so module. The apxs tool automat-
ically complains if this is not the case. You can check
this yourself 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 auto-
matically 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 compilers 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 doc-
umentation of mod_so or perhaps even read the src/mod-
ules/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 deter-
mine the name from the source or (as a fall-
back) at least by guessing it from the file-
name.
QUERY OPTIONS
-q Performs a query for apxs's knowledge about
certain settings. The query parameters can
be one or more of the following strings: CC,
CFLAGS, CFLAGS_SHLIB, INCLUDEDIR, LD_SHLIB,
LDFLAGS_SHLIB, LIBEXECDIR, LIBS_SHLIB,
SBINDIR, SYSCONFDIR, TARGET. .PP Use this
for manually determining settings. For
instance use .nf INC=-I`apxs -q INCLUDEDIR`
.fi .PP 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 file-
name in files and thus usually 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
process.
-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 addi-
tional flags to the compiler command. Use
this to add local compiler-specific options.
-Wl,linker-flags
This option passes linker-flags as addi-
tional 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 simi-
larly 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
accomplish 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" direc-
tory 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
sample Apache module template plus a corresponding Make-
file 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.
Apache HTTP Server 2003-04-29 APXS(8)
