3d938807f61d2c1098dae31429157946b908b2f8
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 #include <stdarg.h>
39 #ifdef __cplusplus
40 extern "C" {
41 #endif
43 typedef struct {
44 sdb_time_t interval;
45 } sdb_plugin_ctx_t;
46 #define SDB_PLUGIN_CTX_INIT { 0 }
48 struct sdb_plugin_info;
49 typedef struct sdb_plugin_info sdb_plugin_info_t;
51 /* this should be used in the header of a plugin to avoid
52 * missing prototype warnings/errors for the plugin init
53 * function */
54 #define SDB_PLUGIN_MAGIC \
55 int sdb_module_init(sdb_plugin_info_t *info)
57 typedef struct {
58 _Bool do_loop;
59 sdb_time_t default_interval;
60 } sdb_plugin_loop_t;
61 #define SDB_PLUGIN_LOOP_INIT { 1, 0 }
63 /*
64 * sdb_plugin_load:
65 * Load (any type of) plugin by loading the shared object file and calling the
66 * sdb_module_init function. If specified, 'plugin_ctx' fine-tunes the
67 * behavior of the plugin. If specified, the plugin will be looked up in
68 * 'basedir', else it defaults to the package libdir.
69 */
70 int
71 sdb_plugin_load(const char *basedir, const char *name,
72 const sdb_plugin_ctx_t *plugin_ctx);
74 /*
75 * sdb_plugin_set_info:
76 * Fill in the fields of the sdb_plugin_info_t object passed to the
77 * sdb_module_init function. This information is used to identify the plugin
78 * and also to provide additional information to the user.
79 */
80 enum {
81 SDB_PLUGIN_INFO_DESC, /* plugin description: string */
82 SDB_PLUGIN_INFO_COPYRIGHT, /* plugin copyright: string */
83 SDB_PLUGIN_INFO_LICENSE, /* plugin license: string */
84 SDB_PLUGIN_INFO_VERSION, /* libsysdb version: integer */
85 SDB_PLUGIN_INFO_PLUGIN_VERSION /* plugin version: integer */
86 };
88 int
89 sdb_plugin_set_info(sdb_plugin_info_t *info, int type, ...);
91 /*
92 * plugin callback functions:
93 * See the description of the respective register function for what arguments
94 * the callbacks expect.
95 *
96 * The specified name of callback functions is prepended with the plugin name
97 * before being registered with the core.
98 */
100 typedef int (*sdb_plugin_config_cb)(oconfig_item_t *ci);
101 typedef int (*sdb_plugin_init_cb)(sdb_object_t *user_data);
102 typedef int (*sdb_plugin_collector_cb)(sdb_object_t *user_data);
103 typedef char *(*sdb_plugin_cname_cb)(const char *name,
104 sdb_object_t *user_data);
105 typedef int (*sdb_plugin_shutdown_cb)(sdb_object_t *user_data);
106 typedef int (*sdb_plugin_log_cb)(int prio, const char *msg,
107 sdb_object_t *user_data);
109 /*
110 * sdb_plugin_register_config:
111 * Register a "config" function. This will be used to pass on the
112 * configuration for a plugin. The plugin has to make sure that the function
113 * can be called multiple times in order to process multiple <Plugin> blocks
114 * specified in the configuration file(s).
115 *
116 * Returns:
117 * - 0 on success
118 * - a negative value else
119 */
120 int
121 sdb_plugin_register_config(sdb_plugin_config_cb callback);
123 /*
124 * sdb_plugin_register_init:
125 * Register an "init" function. All "init" functions will be called after
126 * finishing the config parsing and before starting any other work. The
127 * functions will be called in the same order as they have been registered,
128 * that is, functions of different plugins will be called in the same order as
129 * the appropriate "Load" statements in the config file.
130 *
131 * If the "init" function returns a non-zero value, *all* callbacks of the
132 * plugin will be unloaded.
133 *
134 * Arguments:
135 * - user_data: If specified, this will be passed on to each call of the
136 * callback. The function will take ownership of the object, that is,
137 * increment the reference count by one. In case the caller does not longer
138 * use the object for other purposes, it should thus deref it.
139 *
140 * Returns:
141 * - 0 on success
142 * - a negative value else
143 */
144 int
145 sdb_plugin_register_init(const char *name, sdb_plugin_init_cb callback,
146 sdb_object_t *user_data);
148 /*
149 * sdb_plugin_register_collector:
150 * Register a "collector" function. This is where a backend is doing its main
151 * work. This function will be called whenever an update of a backend has been
152 * requested (either by regular interval or by user request). The backend
153 * should then query the appropriate data-source and submit all values to the
154 * core.
155 *
156 * Arguments:
157 * - interval: Specifies the regular interval at which to update the backend.
158 * If this is NULL, global settings will be used.
159 * - user_data: If specified, this will be passed on to each call of the
160 * callback. The function will take ownership of the object, that is,
161 * increment the reference count by one. In case the caller does not longer
162 * use the object for other purposes, it should thus deref it.
163 *
164 * Returns:
165 * - 0 on success
166 * - a negative value else
167 */
168 int
169 sdb_plugin_register_collector(const char *name,
170 sdb_plugin_collector_cb callback,
171 const sdb_time_t *interval, sdb_object_t *user_data);
173 /*
174 * sdb_plugin_register_cname:
175 * Register a "cname" (canonicalize name) function. This type of function is
176 * called whenever a host is stored. It accepts the hostname and returns a
177 * canonicalized hostname which will then be used to actually store the host.
178 * If multiple such callbacks are registered, each one of them will be called
179 * in the order they have been registered, each one receiving the result of
180 * the previous callback. If the function returns NULL, the original hostname
181 * is not changed. Any other value has to be dynamically allocated. It will be
182 * freed later on by the core.
183 *
184 * Returns:
185 * - 0 on success
186 * - a negative value else
187 */
188 int
189 sdb_plugin_register_cname(const char *name, sdb_plugin_cname_cb callback,
190 sdb_object_t *user_data);
192 /*
193 * sdb_plugin_register_shutdown:
194 * Register a "shutdown" function to be called after stopping all update
195 * processes and before shutting down the daemon.
196 *
197 * Arguments:
198 * - user_data: If specified, this will be passed on to each call of the
199 * callback. The function will take ownership of the object, that is,
200 * increment the reference count by one. In case the caller does not longer
201 * use the object for other purposes, it should thus deref it.
202 */
203 int
204 sdb_plugin_register_shutdown(const char *name,
205 sdb_plugin_shutdown_cb callback,
206 sdb_object_t *user_data);
208 /*
209 * sdb_plugin_register_log:
210 * Register a "log" function to be called whenever logging is to be done.
211 *
212 * Arguments:
213 * - user_data: If specified, this will be passed on to each call of the
214 * callback. The function will take ownership of the object, that is,
215 * increment the reference count by one. In case the caller does not longer
216 * use the object for other purposes, it should thus deref it.
217 */
218 int
219 sdb_plugin_register_log(const char *name, sdb_plugin_log_cb callback,
220 sdb_object_t *user_data);
222 /*
223 * sdb_plugin_get_ctx, sdb_plugin_set_ctx:
224 * The plugin context defines a set of settings that are available whenever a
225 * plugin has been called. It may be used to pass around various information
226 * between the different component of the library without having each and
227 * every plugin care about it.
228 *
229 * If non-NULL, sdb_plugin_set_ctx stores the previous context in the location
230 * pointed to by 'old'.
231 */
232 sdb_plugin_ctx_t
233 sdb_plugin_get_ctx(void);
234 int
235 sdb_plugin_set_ctx(sdb_plugin_ctx_t ctx, sdb_plugin_ctx_t *old);
237 /*
238 * sdb_plugin_configure:
239 * Configure the plugin called 'name' using the config tree 'ci'. The plugin
240 * name is the same as the one used when loading the plugin.
241 *
242 * Returns:
243 * - 0 on success
244 * - a negative value else
245 */
246 int
247 sdb_plugin_configure(const char *name, oconfig_item_t *ci);
249 /*
250 * sdb_plugin_reconfigure_init, sdb_plugin_reconfigure_finish:
251 * Reconfigure all plugins. This happens in multiple steps: first, call
252 * sdb_plugin_reconfigure_init to deconfigure all plugins by calling their
253 * config callbacks with a NULL config tree and unregistering all callbacks.
254 * Then, sdb_plugin_configure and other functions may be used to provide the
255 * new configuration or load new plugins. For all plugins which were already
256 * loaded before, sdb_module_init will be called with a NULL argument when
257 * reloading them.
258 * Finally, sdb_plugin_reconfigure_finish will clean up leftover pieces, like
259 * unloading plugins which are no longer in use.
260 *
261 * Returns:
262 * - 0 on success
263 * - a negative value else
264 */
265 int
266 sdb_plugin_reconfigure_init(void);
267 int
268 sdb_plugin_reconfigure_finish(void);
270 /*
271 * sdb_plugin_init_all:
272 * Initialize all plugins using their registered "init" function.
273 *
274 * Returns:
275 * The number of failed initializations.
276 */
277 int
278 sdb_plugin_init_all(void);
280 /*
281 * sdb_plugin_shutdown_all:
282 * Shutdown all plugins using their registered "shutdown" function.
283 *
284 * Returns:
285 * The number of failed shutdowns.
286 */
287 int
288 sdb_plugin_shutdown_all(void);
290 /*
291 * sdb_plugin_collector_loop:
292 * Loop until loop->do_loop is false, calling the next collector function on
293 * each iteration and once its next update interval is passed.
294 *
295 * Returns:
296 * - 0 on success
297 * - a negative value else
298 */
299 int
300 sdb_plugin_collector_loop(sdb_plugin_loop_t *loop);
302 /*
303 * sdb_plugin_cname:
304 * Returns the canonicalized hostname. The given hostname argument has to
305 * point to dynamically allocated memory and might be freed by the function.
306 * The return value will also be dynamically allocated (but it might be
307 * unchanged) and has to be freed by the caller.
308 */
309 char *
310 sdb_plugin_cname(char *hostname);
312 /*
313 * sdb_plugin_log:
314 * Log the specified message using all registered log callbacks. The message
315 * will be logged with the specified priority.
316 */
317 int
318 sdb_plugin_log(int prio, const char *msg);
320 /*
321 * sdb_plugin_logf:
322 * Log a formatted message. See sdb_plugin_log for more information.
323 */
324 int
325 sdb_plugin_vlogf(int prio, const char *fmt, va_list ap);
326 int
327 sdb_plugin_logf(int prio, const char *fmt, ...);
329 #ifdef __cplusplus
330 } /* extern "C" */
331 #endif
333 #endif /* ! SDB_CORE_PLUGIN_H */
335 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */