OpenBSD-4.6/usr.sbin/httpd/src/support/apxs.8
.\" $OpenBSD: apxs.8,v 1.15 2007/05/31 19:20:24 jmc Exp $
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.Dd $Mdocdate: May 31 2007 $
.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,
.Xr httpd 8 .
This is achieved by building a
Dynamic Shared Object (DSO)
from one or more source or object files
which can then be loaded into httpd at runtime via the
.Ic LoadModule
directive from
.Ic mod_so .
To use this extension mechanism,
your platform has to support the DSO feature
and the httpd binary has to be built with the
.Ic mod_so
module.
The
.Nm
tool automatically complains if this is not the case.
Check by manually running the following command:
.Pp
.Dl $ httpd -l
.Pp
The module
.Ic mod_so
should be part of the displayed list.
If these requirements are fulfilled,
httpd's functionality can be extended by
installing modules with the DSO mechanism,
with the help of the
.Nm
tool:
.Bd -literal -offset indent
# apxs -i -a -c mod_foo.c
cc -O2 -pipe -DDEV_RANDOM=/dev/arandom -DMOD_SSL=208116 -DEAPI -DUSE_EXPAT -I../lib/expat-lite -DUSE_SETUSERCONTEXT -fPIC -DSHARED_MODULE -I/usr/lib/apache/include -c mod_foo.c
[activating module `foo' in /var/www/conf/httpd.conf]
cp mod_foo.so /usr/lib/apache/modules/mod_foo.so
chmod 755 /usr/lib/apache/modules/mod_foo.so
cp /var/www/conf/httpd.conf /var/www/conf/httpd.conf.bak
cp /var/www/conf/httpd.conf.new /var/www/conf/httpd.conf
rm /var/www/conf/httpd.conf.new
# apachectl restart
/usr/sbin/apachectl restart: httpd not running, trying to start
/usr/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
.Xr cc 1
just 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
Compile.
This option 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
.No mod_ Ns Ar name Ns \&.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
Edit.
This option can be used with the
.Fl a
and
.Fl A
options to edit the
configuration file,
.Pa /var/www/conf/httpd.conf ,
without attempting to install the module.
.It Fl g
Template generation.
This option generates a subdirectory
.Ar name
(see the
.Fl n
option)
and two files:
a sample module source file named
.No mod_ Ns Ar name Ns \&.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
Install.
This option 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
Query.
This option 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.
This option may be specified multiple times
in order to pass multiple flags.
.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.
This option may be specified multiple times
in order to pass multiple flags.
.El
.Sh EXAMPLES
Assume you have a module named
.Dq mod_foo.c
available which should extend httpd's functionality.
To accomplish this,
first compile the C source into a DSO
suitable for loading into httpd at runtime via the following command:
.Bd -literal -offset indent
# apxs -c mod_foo.c
cc -O2 -pipe -DDEV_RANDOM=/dev/arandom -DMOD_SSL=208116 -DEAPI -DUSE_EXPAT -I../lib/expat-lite -DUSE_SETUSERCONTEXT -fPIC -DSHARED_MODULE -I/usr/lib/apache/include -c mod_foo.c
cc -shared -fPIC -DSHARED_MODULE -o mod_foo.so mod_foo.o
.Ed
.Pp
Then a
.Ic LoadModule
directive has to be added to httpd's configuration file to load the DSO.
To simplify this step,
.Nm
provides an automatic way to install the DSO in the
.Dq libexec
directory and update the httpd.conf file accordingly.
This can be achieved by running the following:
.Bd -literal -offset indent
$ apxs -i -a mod_foo.so
[activating module `foo' in /var/www/conf/httpd.conf]
cp mod_foo.so /usr/lib/apache/modules/mod_foo.so
chmod 755 /usr/lib/apache/modules/mod_foo.so
cp /var/www/conf/httpd.conf /var/www/conf/httpd.conf.bak
cp /var/www/conf/httpd.conf.new /var/www/conf/httpd.conf
rm /var/www/conf/httpd.conf.new
.Ed
.Pp
This way a line such as the following
is added to the configuration file:
.Pp
.Dl LoadModule foo_module /usr/lib/apache/modules/mod_foo.so
.Pp
If you want the module added to the configuration file
without it being enabled,
use the
.Fl A
option instead:
.Pp
.Dl $ apxs -i -A mod_foo.so
.Pp
For a quick test of the
.Nm
mechanism,
create a sample 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
The sample module can then be immediately compiled into a DSO
and loaded into the httpd server:
.Bd -literal -offset indent
$ cd foo
$ make all reload
apxs -c mod_foo.c
cc -O2 -pipe -DDEV_RANDOM=/dev/arandom -DMOD_SSL=208116 -DEAPI -DUSE_EXPAT -I../lib/expat-lite -DUSE_SETUSERCONTEXT -fPIC -DSHARED_MODULE -I/usr/lib/apache/include -c mod_foo.c
cc -shared -fPIC -DSHARED_MODULE -o mod_foo.so mod_foo.o
apxs -i -a -n 'foo' mod_foo.so
[activating module `foo' in /var/www/conf/httpd.conf]
cp mod_foo.so /usr/lib/apache/modules/mod_foo.so
chmod 755 /usr/lib/apache/modules/mod_foo.so
cp /var/www/conf/httpd.conf /var/www/conf/httpd.conf.bak
cp /var/www/conf/httpd.conf.new /var/www/conf/httpd.conf
rm /var/www/conf/httpd.conf.new
apachectl restart
/usr/sbin/apachectl restart: httpd not running, trying to start
/usr/sbin/apachectl restart: httpd started
.Ed
.Pp
.Nm
can even be used to compile complex modules
outside the httpd 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 cc 1 ,
.Xr apachectl 8 ,
.Xr httpd 8