8:apxs2
From Linux Man Pages
apxs - APache eXtenSion tool
Contents |
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,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 ...
SUMMARY
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 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 automatically 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 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 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 documentation 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
determine the name from the source or (as a fallback) at least by guessing it from the filename.
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
INC=-I`apxs -q INCLUDEDIR` .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 corre-
sponding 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 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 additional flags to the libtool --mode=compile command. Use this to
add local compiler-specific options.
-Wl,linker-flags
This option passes linker-flags as additional flags to the libtool --mode=link 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
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
/path/to/libtool --mode=compile gcc ... -c mod_foo.c
/path/to/libtool --mode=link gcc ... -o mod_foo.la mod_foo.slo
$ _
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.la
/path/to/instdso.sh mod_foo.la /path/to/apache/modules
/path/to/libtool --mode=install cp mod_foo.la /path/to/apache/modules
...
chmod 755 /path/to/apache/modules/mod_foo.so
[activating module `foo' in /path/to/apache/conf/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/modules.mk
Creating [FILE] foo/mod_foo.c
Creating [FILE] foo/.deps
$ _
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
/path/to/libtool --mode=compile gcc ... -c mod_foo.c
/path/to/libtool --mode=link gcc ... -o mod_foo.la mod_foo.slo
apxs -i -a -n "foo" mod_foo.la
/path/to/instdso.sh mod_foo.la /path/to/apache/modules
/path/to/libtool --mode=install cp mod_foo.la /path/to/apache/modules
...
chmod 755 /path/to/apache/modules/mod_foo.so
[activating module `foo' in /path/to/apache/conf/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
$ _