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Apache HTTP Server Version 1.3
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NAME
apxs - APache eXtenSion tool
SYNOPSIS
apxs -g [ -S variable=value ] -n name
apxs -q [ -S variable=value ] query ...
apxs -c [ -S variable=value ] [ -o dsofile ] [ -I incdir ] [
-D variable[=value] ] [ -L libdir ] [ -l libname ] [
-Wc,compiler-flags ] [ -Wl,linker-flags ] files ...
apxs -i [ -S variable=value ] [ -n name ] [ -a ] [ -A ] dso-
file ...
apxs -e [ -S variable=value ] [ -n name ] [ -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
support the DSO feature and your Apache httpd binary has to
be built with the mod_so module. The apxs tool automati-
cally 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/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
$ _
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
uses the C source files for compilation while 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 always just have to use
-fpic. For other C compilers please consult its manual page
or watch for the flags apxs uses to compile the object
files.
For more details about DSO support in Apache, first read the
background information about DSO in htdocs/manual/dso.html,
then read the documentation of mod_so.
OPTIONS
Common options:
-n name 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 variable names:
CC TARGET
CFLAGS SBINDIR
CFLAGS_SHLIB INCLUDEDIR
LD_SHLIB LIBEXECDIR
LDFLAGS_SHLIB SYSCONFDIR
LIBS_SHLIB PREFIX
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 variable=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
building 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 DSO 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
DSO file. If not specified and the name cannot
be guessed from the files list, the fallback
name mod_unknown.so is used.
-D variable[=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 DSOs into the server's
libexec 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 DSO
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 DSO. To
simplify this step apxs provides an automatic way to install
the DSO in the "libexec" directory and updating the
httpd.conf file accordingly. This can be achieved by run-
ning:
$ 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]
$ _
This way a line named
LoadModule foo_module libexec/mod_foo.so
is added to the configuration file if still not present. If
you want to have this operation to be disabled, 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
DSO 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/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
$ _
You can even use apxs to compile complex modules outside the
Apache source tree, like PHP3, because apxs automatically
recognized C source files and object files.
$ 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
$ _
Only C source files are compiled while remaining object
files are used for the linking phase.
SEE ALSO
apachectl(1), httpd(8).
