path: root/usr.sbin/httpd/src/support/apxs.8

.\"	$OpenBSD: apxs.8,v 1.12 2004/12/07 15:48:57 jmc Exp $
.\"
.\" ====================================================================
.\" The Apache Software License, Version 1.1
.\"
.\" Copyright (c) 2000-2003 The Apache Software Foundation.  All rights
.\" reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\"
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\"
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in
.\"    the documentation and/or other materials provided with the
.\"    distribution.
.\"
.\" 3. The end-user documentation included with the redistribution,
.\"    if any, must include the following acknowledgment:
.\"       "This product includes software developed by the
.\"        Apache Software Foundation (http://www.apache.org/)."
.\"    Alternately, this acknowledgment may appear in the software itself,
.\"    if and wherever such third-party acknowledgments normally appear.
.\"
.\" 4. The names "Apache" and "Apache Software Foundation" must
.\"    not be used to endorse or promote products derived from this
.\"    software without prior written permission. For written
.\"    permission, please contact apache@apache.org.
.\"
.\" 5. Products derived from this software may not be called "Apache",
.\"    nor may "Apache" appear in their name, without prior written
.\"    permission of the Apache Software Foundation.
.\"
.\" THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
.\" WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
.\" DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
.\" ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
.\" SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
.\" LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
.\" USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
.\" ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
.\" OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
.\" OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\" ====================================================================
.\"
.\" This software consists of voluntary contributions made by many
.\" individuals on behalf of the Apache Software Foundation.  For more
.\" information on the Apache Software Foundation, please see
.\" <http://www.apache.org/>.
.\"
.\" Portions of this software are based upon public domain software
.\" originally written at the National Center for Supercomputing Applications,
.\" University of Illinois, Urbana-Champaign.
.\"
.Dd December 7, 2004
.Dt APXS 8
.Os
.Sh NAME
.Nm apxs
.Nd APache eXtenSion tool
.Sh SYNOPSIS
.Nm
.Bk -words
.Fl c
.Xo
.Oo Fl D
.Ar variable Ns Oo = Ns Ar value Oc Oc
.Xc
.Op Fl I Ar incdir
.Op Fl L Ar libdir
.Op Fl l Ar libname
.No \ \&\ \& Op Fl o Ar dsofile
.Xo
.Oo Fl S
.Ar variable Ns = Ns Ar value Oc
.Xc
.Op Fl Wc , Ns Ar compiler-flags
.No \ \&\ \& Op Fl Wl , Ns Ar linker-flags
.Ar file ...
.Ek
.Nm
.Fl e
.Op Fl Aa
.Op Fl n Ar name
.Xo
.Oo Fl S
.Ar variable Ns = Ns Ar value Oc
.Xc
.Ar dsofile ...
.Nm
.Fl g
.Xo
.Oo Fl S
.Ar variable Ns = Ns Ar value Oc
.Xc
.Fl n Ar name
.Nm
.Fl i
.Op Fl Aa
.Op Fl n Ar name
.Xo
.Oo Fl S
.Ar variable Ns = Ns Ar value Oc
.Xc
.Ar dsofile ...
.Nm
.Fl q
.Xo
.Oo Fl S
.Ar variable Ns = Ns Ar value Oc
.Xc
.Ar query ...
.Sh DESCRIPTION
.Nm
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 can then be loaded into
.Xr httpd 8
at runtime via the
.Ic LoadModule
directive from
.Ic mod_so .
So to use this extension mechanism,
your platform has to support the DSO feature and your
.Xr httpd 8
binary has to be built with the
.Ic mod_so
module.
The
.Nm
tool automatically complains if this is not the case.
You can check this yourself by manually running the command
.Pp
.Dl $ httpd -l
.Pp
The module
.Ic 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,
with the help of the
.Nm
tool:
.Bd -literal -offset indent
$ 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/libexec/mod_foo.so
chmod 755 /path/to/apache/libexec/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
$ _
.Ed
.Pp
The argument
.Ar file
can be any C source file (.c),
an object file (.o),
or even a library archive (.a).
The
.Nm
tool automatically recognizes these extensions and automatically uses the C
source files for compilation,
whereas it just uses 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 DSO.
For instance, with GCC you just have to always use
.Fl fpic .
For other
C compilers, please consult their manual
pages or watch for the flags
.Nm
uses to compile the object files.
.Pp
For more details about DSO support in Apache,
first read the background information about DSO in
.Pa htdocs/manual/dso.html ,
then read the documentation of
.Ic mod_so .
.Pp
The options are as follows:
.Bl -tag -width Ds
.It Fl A
Same as the
.Fl a
option but the created
.Ic LoadModule
directive is prefixed with a hash sign (#),
i.e. the module is just prepared for later activation but initially disabled.
.It Fl a
This activates the module by automatically adding a corresponding
.Ic LoadModule
line to Apache's httpd.conf configuration file,
or by enabling it if it already exists.
.It Fl c
This indicates the compilation operation.
It first compiles the C source files (.c) of
.Ar file ...\&
into corresponding object files (.o) and then builds a DSO in
.Ar dsofile
by linking these object files plus the remaining object files (.o and .a) of
.Ar file ...
If no
.Fl o
option is specified,
the output file is guessed from the first filename in
.Ar file ...\&
and thus usually defaults to
.Ar mod_name.so
.It Xo
.Fl D
.Ar variable Ns Op = Ns Ar value
.Xc
This option is directly passed through to the compilation command(s).
Use this to add your own defines to the build process.
.It Fl e
This indicates the editing operation, which can be used with the
.Fl a
and
.Fl A
options similarly to the
.Fl i
operation to edit Apache's httpd.conf configuration file,
without attempting to install the module.
.It Fl g
This generates a subdirectory
.Ar name
(see the
.Fl n
option)
and two files:
a sample module source file named
.Pa mod_name.c
which can be used as a template for creating your own modules or
as a quick start for playing with the
.Nm
mechanism,
and a corresponding
.Pa Makefile
for even easier building and installing of this module.
.It Fl I Ar 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.
.It Fl i
This indicates the installation operation and installs one or more
DSOs into the server's
.Ar libexec
directory.
.It Fl L Ar 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.
.It Fl l Ar libname
This option is directly passed through to the linker command.
Use this to add your own libraries to search to the build process.
.It Fl n Ar name
This explicitly sets the module name for the
.Fl i
(install)
and
.Fl g
(template generation) option.
Use this to explicitly specify the module name.
For option
.Fl g
this is required;
for option
.Fl i ,
.Nm
tries to determine the name from the source or (as a fallback) at least
by guessing it from the filename.
.It Fl o Ar dsofile
Explicitly specifies the filename of the created DSO file.
If not specified and the name cannot be guessed from the
.Ar file ...\&
list,
the fallback name
.Ar mod_unknown.so
is used.
.It Fl q
Performs a query for
.Nm apxs Ns 's
knowledge about certain settings.
The
.Ar query
parameters can be one or more of the following variable names:
.Bd -literal -offset indent
CC              TARGET
CFLAGS          SBINDIR
CFLAGS_SHLIB    INCLUDEDIR
LD_SHLIB        LIBEXECDIR
LDFLAGS_SHLIB   SYSCONFDIR
LIBS_SHLIB      PREFIX
.Ed
.Pp
Use this for manually determining settings.
For instance,
use the following inside your own Makefiles if you need manual access
to Apache's C header files:
.Pp
.Dl INC=-I`apxs -q INCLUDEDIR`
.It Fl S Ar variable Ns = Ns Ar value
This option changes the
.Nm
settings described above.
.It Fl Wc , Ns Ar compiler-flags
This option passes
.Ar compiler-flags
as additional flags to the compiler command.
Use this to add local compiler-specific options.
.It Fl Wl , Ns Ar linker-flags
This option passes
.Ar linker-flags
as additional flags to the linker command.
Use this to add local linker-specific options.
.El
.Sh EXAMPLES
Assume you have an Apache module named
.Dq mod_foo.c
available which should extend Apache's server functionality.
To accomplish this you first have to compile
the C source into a DSO suitable for loading into the Apache server
under runtime via the following command:
.Bd -literal -offset indent
$ 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
$ _
.Ed
.Pp
Then you have to update the Apache configuration by making sure a
.Ic LoadModule
directive is present to load this DSO.
To simplify this step,
.Nm
provides an automatic way to install the DSO in the
.Dq libexec
directory and updating the httpd.conf file accordingly.
This can be achieved by running:
.Bd -literal -offset indent
$ apxs -i -a mod_foo.c
cp mod_foo.so /path/to/apache/libexec/mod_foo.so
chmod 755 /path/to/apache/libexec/mod_foo.so
[activating module `foo' in /path/to/apache/etc/httpd.conf]
$ _
.Ed
.Pp
This way a line named
.Pp
.Dl LoadModule foo_module libexec/mod_foo.so
.Pp
is added to the configuration file, if still not present.
If you want this operation to be disabled, use the
.Fl A
option, i.e.
.Pp
.Dl $ apxs -i -A mod_foo.c
.Pp
For a quick test of the
.Nm
mechanism you can create a sample Apache module
template plus a corresponding
.Ar Makefile
via:
.Bd -literal -offset indent
$ apxs -g -n foo
Creating [DIR]  foo
Creating [FILE] foo/Makefile
Creating [FILE] foo/mod_foo.c
$ _
.Ed
.Pp
Then you can immediately compile this sample module into a DSO and
load it into the Apache server:
.Bd -literal -offset indent
$ 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/libexec/mod_foo.so
chmod 755 /path/to/apache/libexec/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
$ _
.Ed
.Pp
You can even use
.Nm
to compile complex modules outside the Apache source tree, like PHP3, because
.Nm
automatically recognizes C source files and object files.
.Bd -literal -offset indent
$ 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
$ _
.Ed
.Pp
Only C source files are compiled,
while remaining object files are used for the linking phase.
.Sh SEE ALSO
.Xr apachectl 1 ,
.Xr httpd 8