Chapter 8. Modules

Some subsystems in samba use different backends. These backends can be either statically linked in to samba or available as a plugin. A subsystem should have a function that allows a module to register itself. For example, @@ -11,7 +11,7 @@ NTSTATUS smb_register_passdb(int version, const char *name, pdb_init_function in

This function will be called by the initialisation function of the module to register itself. -

Static modules

The modules system compiles a list of initialisation functions for the static modules of each subsystem. This is a define. For example, it is here currently (from include/config.h): @@ -21,7 +21,7 @@ it is here currently (from include/config.h):

These functions should be called before the subsystem is used. That should be done when the subsystem is initialised or first used. -

Shared modules

If a subsystem needs a certain backend, it should check if it has already been registered. If the backend hasn't been registered already, the subsystem should call smb_probe_module(char *subsystem, char *backend). @@ -31,7 +31,7 @@ is a slash, smb_probe_module() tries to load the module from the absolute path specified in 'backend'.

After smb_probe_module() has been executed, the subsystem should check again if the module has been registered. -

Writing modules

Each module has an initialisation function. For modules that are included with samba this name is 'subsystem_backend_init'. For external modules (that will never be built-in, but only available as a module) this name is always 'init_module'. (In the case of modules included with samba, the configure system will add a #define subsystem_backend_init() init_module()). The prototype for these functions is: @@ -46,7 +46,7 @@ smb_register_passdb(PASSDB_INTERFACE_VERSION, "ldapsam", pdb_init_ldapsam); smb_register_passdb(PASSDB_INTERFACE_VERSION, "ldapsam_nua", pdb_init_ldapsam_nua); return NT_STATUS_OK; } -

Static/Shared selection in configure.in

Some macros in configure.in generate the various defines and substs that are necessary for the system to work correct. All modules that should be built by default have to be added to the variable 'default_modules'. @@ -64,7 +64,7 @@ be replaced with the names of the plugins to build.

You must make sure all .c files that contain defines that can be changed by ./configure are rebuilded in the 'modules_clean' make target. Practically, this means all c files that contain static_init_subsystem; calls need to be rebuilded. -

Note

There currently also is a configure.in command called SMB_MODULE_PROVIVES(). This is used for modules that register multiple things. It should not be used as probing will most likely disappear in the future.

Prev	Up	Next
Chapter 7. Contributing code	Home	Part III. Samba Subsystems

-- cgit v1.2.3