1 /*
2 * SysDB - src/include/core/plugin.h
3 * Copyright (C) 2012 Sebastian 'tokkee' Harl <sh@tokkee.org>
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
17 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
18 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR
19 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
20 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
21 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
22 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
23 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
24 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
25 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
28 #ifndef SDB_CORE_PLUGIN_H
29 #define SDB_CORE_PLUGIN_H 1
31 #include "sysdb.h"
32 #include "core/object.h"
33 #include "core/time.h"
35 #include "liboconfig/oconfig.h"
37 #ifdef __cplusplus
38 extern "C" {
39 #endif
41 typedef struct {
42 sdb_time_t interval;
43 } sdb_plugin_ctx_t;
44 #define SDB_PLUGIN_CTX_INIT { 0 }
46 struct sdb_plugin_info;
47 typedef struct sdb_plugin_info sdb_plugin_info_t;
49 /* this should be used in the header of a plugin to avoid
50 * missing prototype warnings/errors for the plugin init
51 * function */
52 #define SDB_PLUGIN_MAGIC \
53 int sdb_module_init(sdb_plugin_info_t *info);
55 typedef struct {
56 _Bool do_loop;
57 sdb_time_t default_interval;
58 } sdb_plugin_loop_t;
59 #define SDB_PLUGIN_LOOP_INIT { 1, 0 }
61 /*
62 * sdb_plugin_load:
63 * Load (any type of) plugin by loading the shared object file and calling the
64 * sdb_module_init function.
65 */
66 int
67 sdb_plugin_load(const char *name);
69 /*
70 * sdb_plugin_set_info:
71 * Fill in the fields of the sdb_plugin_info_t object passed to the
72 * sdb_module_init function. This information is used to identify the plugin
73 * and also to provide additional information to the user.
74 */
75 enum {
76 SDB_PLUGIN_INFO_NAME, /* plugin name: string */
77 SDB_PLUGIN_INFO_DESC, /* plugin description: string */
78 SDB_PLUGIN_INFO_COPYRIGHT, /* plugin copyright: string */
79 SDB_PLUGIN_INFO_LICENSE, /* plugin license: string */
80 SDB_PLUGIN_INFO_VERSION, /* libsysdb version: integer */
81 SDB_PLUGIN_INFO_PLUGIN_VERSION /* plugin version: integer */
82 };
84 int
85 sdb_plugin_set_info(sdb_plugin_info_t *info, int type, ...);
87 /*
88 * plugin callback functions
89 */
91 typedef int (*sdb_plugin_config_cb)(oconfig_item_t *ci);
92 typedef int (*sdb_plugin_init_cb)(sdb_object_t *user_data);
93 typedef int (*sdb_plugin_collector_cb)(sdb_object_t *user_data);
94 typedef int (*sdb_plugin_shutdown_cb)(sdb_object_t *user_data);
95 typedef int (*sdb_plugin_log_cb)(int prio, const char *msg,
96 sdb_object_t *user_data);
98 /*
99 * sdb_plugin_register_config:
100 * Register a "config" function. This will be used to pass on the
101 * configuration for a plugin. The plugin has to make sure that the function
102 * can be called multiple times in order to process multiple <Plugin> blocks
103 * specified in the configuration file(s).
104 *
105 * Returns:
106 * - 0 on success
107 * - a negative value else
108 */
109 int
110 sdb_plugin_register_config(const char *name, sdb_plugin_config_cb callback);
112 /*
113 * sdb_plugin_register_init:
114 * Register an "init" function. All "init" functions will be called after
115 * finishing the config parsing and before starting any other work. The
116 * functions will be called in the same order as they have been registered,
117 * that is, functions of different plugins will be called in the same order as
118 * the appropriate "Load" statements in the config file.
119 *
120 * If the "init" function returns a non-zero value, *all* callbacks of the
121 * plugin will be unloaded.
122 *
123 * Arguments:
124 * - user_data: If specified, this will be passed on to each call of the
125 * callback. The function will take ownership of the object, that is,
126 * increment the reference count by one. In case the caller does not longer
127 * use the object for other purposes, it should thus deref it.
128 *
129 * Returns:
130 * - 0 on success
131 * - a negative value else
132 */
133 int
134 sdb_plugin_register_init(const char *name, sdb_plugin_init_cb callback,
135 sdb_object_t *user_data);
137 /*
138 * sdb_plugin_register_collector:
139 * Register a "collector" function. This is where a backend is doing its main
140 * work. This function will be called whenever an update of a backend has been
141 * requested (either by regular interval or by user request). The backend
142 * should then query the appropriate data-source and submit all values to the
143 * core.
144 *
145 * Arguments:
146 * - interval: Specifies the regular interval at which to update the backend.
147 * If this is NULL, global settings will be used.
148 * - user_data: If specified, this will be passed on to each call of the
149 * callback. The function will take ownership of the object, that is,
150 * increment the reference count by one. In case the caller does not longer
151 * use the object for other purposes, it should thus deref it.
152 *
153 * Returns:
154 * - 0 on success
155 * - a negative value else
156 */
157 int
158 sdb_plugin_register_collector(const char *name,
159 sdb_plugin_collector_cb callback,
160 const sdb_time_t *interval, sdb_object_t *user_data);
162 /*
163 * sdb_plugin_register_shutdown:
164 * Register a "shutdown" function to be called after stopping all update
165 * processes and before shutting down the daemon.
166 *
167 * Arguments:
168 * - user_data: If specified, this will be passed on to each call of the
169 * callback. The function will take ownership of the object, that is,
170 * increment the reference count by one. In case the caller does not longer
171 * use the object for other purposes, it should thus deref it.
172 */
173 int
174 sdb_plugin_register_shutdown(const char *name,
175 sdb_plugin_shutdown_cb callback,
176 sdb_object_t *user_data);
178 /*
179 * sdb_plugin_register_log:
180 * Register a "log" function to be called whenever logging is to be done.
181 *
182 * Arguments:
183 * - user_data: If specified, this will be passed on to each call of the
184 * callback. The function will take ownership of the object, that is,
185 * increment the reference count by one. In case the caller does not longer
186 * use the object for other purposes, it should thus deref it.
187 */
188 int
189 sdb_plugin_register_log(const char *name, sdb_plugin_log_cb callback,
190 sdb_object_t *user_data);
192 /*
193 * sdb_plugin_get_ctx, sdb_plugin_set_ctx:
194 * The plugin context defines a set of settings that are available whenever a
195 * plugin has been called. It may be used to pass around various information
196 * between the different component of the library without having each and
197 * every plugin care about it.
198 */
199 sdb_plugin_ctx_t
200 sdb_plugin_get_ctx(void);
201 sdb_plugin_ctx_t
202 sdb_plugin_set_ctx(sdb_plugin_ctx_t ctx);
204 /*
205 * sdb_plugin_configure:
206 * Configure the plugin called 'name' (according to the registered config
207 * callback) using the config tree 'ci'.
208 *
209 * Returns:
210 * - 0 on success
211 * - a negative value else
212 */
213 int
214 sdb_plugin_configure(const char *name, oconfig_item_t *ci);
216 /*
217 * sdb_plugin_init_all:
218 * Initialize all plugins using their registered "init" function.
219 */
220 int
221 sdb_plugin_init_all(void);
223 /*
224 * sdb_plugin_collector_loop:
225 * Loop until loop->do_loop is false, calling the next collector function on
226 * each iteration and once its next update interval is passed.
227 *
228 * Returns:
229 * - 0 on success
230 * - a negative value else
231 */
232 int
233 sdb_plugin_collector_loop(sdb_plugin_loop_t *loop);
235 /*
236 * sdb_plugin_log:
237 * Log the specified message using all registered log callbacks. The message
238 * will be logged with the specified priority.
239 */
240 int
241 sdb_plugin_log(int prio, const char *msg);
243 #ifdef __cplusplus
244 } /* extern "C" */
245 #endif
247 #endif /* ! SDB_CORE_PLUGIN_H */
249 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */