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/*
* plugin.h: plugin handling
*
* Copyright (c) 2011 Cisco and/or its affiliates.
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef __included_plugin_h__
#define __included_plugin_h__
#include <vlib/vlib.h>
#include <vlib/unix/unix.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
/*
* vlib plugin scheme
*
* Almost anything which can be made to work in a vlib unix
* application will also work in a vlib plugin.
*
* The elf-section magic which registers static objects
* works so long as plugins are preset when the vlib unix process
* starts. But wait: there's more...
*
* If an application calls vlib_load_new_plugins() -- possibly after
* changing vlib_plugin_main.plugin_path / vlib_plugin_main.plugin_name_filter,
* -- new plugins will be loaded. That, in turn, allows considerable
* flexibility in terms of adding feature code or fixing bugs without
* requiring the data-plane process to restart.
*
* When the plugin mechanism loads a plugin, it uses dlsym to locate
* and call the plugin's function vlib_plugin_register() if it exists.
* A plugin which expects to be loaded after the vlib application
* starts uses this callback to modify the application. If vlib_plugin_register
* returns non-zero, the plugin mechanism dlclose()'s the plugin.
*
* Applications control the plugin search path and name filter by
* declaring the variables vlib_plugin_path and vlib_plugin_name_filter.
* libvlib_unix.la supplies weak references for these symbols which
* effectively disable the scheme. In order for the elf-section magic to
* work, static plugins must be loaded at the earliest possible moment.
*
* An application can change these parameters at any time and call
* vlib_load_new_plugins().
*/
typedef struct
{
u8 *name;
struct stat file_info;
void *handle;
} plugin_info_t;
typedef struct
{
/* loaded plugin info */
plugin_info_t *plugin_info;
uword *plugin_by_name_hash;
/* path and name filter */
u8 *plugin_path;
u8 *plugin_name_filter;
/* handoff structure get callback */
void *handoff_structure_get_cb;
/* usual */
vlib_main_t *vlib_main;
} plugin_main_t;
plugin_main_t vlib_plugin_main;
int vlib_plugin_early_init (vlib_main_t * vm);
int vlib_load_new_plugins (plugin_main_t * pm, int from_early_init);
#endif /* __included_plugin_h__ */
/*
* fd.io coding-style-patch-verification: ON
*
* Local Variables:
* eval: (c-set-style "gnu")
* End:
*/
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