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_NAME, /* plugin name: string */
82 SDB_PLUGIN_INFO_DESC, /* plugin description: string */
83 SDB_PLUGIN_INFO_COPYRIGHT, /* plugin copyright: string */
84 SDB_PLUGIN_INFO_LICENSE, /* plugin license: string */
85 SDB_PLUGIN_INFO_VERSION, /* libsysdb version: integer */
86 SDB_PLUGIN_INFO_PLUGIN_VERSION /* plugin version: integer */
87 };
89 int
90 sdb_plugin_set_info(sdb_plugin_info_t *info, int type, ...);
92 /*
93 * plugin callback functions:
94 * See the description of the respective register function for what arguments
95 * the callbacks expect.
96 */
98 typedef int (*sdb_plugin_config_cb)(oconfig_item_t *ci);
99 typedef int (*sdb_plugin_init_cb)(sdb_object_t *user_data);
100 typedef int (*sdb_plugin_collector_cb)(sdb_object_t *user_data);
101 typedef char *(*sdb_plugin_cname_cb)(const char *name,
102 sdb_object_t *user_data);
103 typedef int (*sdb_plugin_shutdown_cb)(sdb_object_t *user_data);
104 typedef int (*sdb_plugin_log_cb)(int prio, const char *msg,
105 sdb_object_t *user_data);
107 /*
108 * sdb_plugin_register_config:
109 * Register a "config" function. This will be used to pass on the
110 * configuration for a plugin. The plugin has to make sure that the function
111 * can be called multiple times in order to process multiple <Plugin> blocks
112 * specified in the configuration file(s).
113 *
114 * Returns:
115 * - 0 on success
116 * - a negative value else
117 */
118 int
119 sdb_plugin_register_config(const char *name, sdb_plugin_config_cb callback);
121 /*
122 * sdb_plugin_register_init:
123 * Register an "init" function. All "init" functions will be called after
124 * finishing the config parsing and before starting any other work. The
125 * functions will be called in the same order as they have been registered,
126 * that is, functions of different plugins will be called in the same order as
127 * the appropriate "Load" statements in the config file.
128 *
129 * If the "init" function returns a non-zero value, *all* callbacks of the
130 * plugin will be unloaded.
131 *
132 * Arguments:
133 * - user_data: If specified, this will be passed on to each call of the
134 * callback. The function will take ownership of the object, that is,
135 * increment the reference count by one. In case the caller does not longer
136 * use the object for other purposes, it should thus deref it.
137 *
138 * Returns:
139 * - 0 on success
140 * - a negative value else
141 */
142 int
143 sdb_plugin_register_init(const char *name, sdb_plugin_init_cb callback,
144 sdb_object_t *user_data);
146 /*
147 * sdb_plugin_register_collector:
148 * Register a "collector" function. This is where a backend is doing its main
149 * work. This function will be called whenever an update of a backend has been
150 * requested (either by regular interval or by user request). The backend
151 * should then query the appropriate data-source and submit all values to the
152 * core.
153 *
154 * Arguments:
155 * - interval: Specifies the regular interval at which to update the backend.
156 * If this is NULL, global settings will be used.
157 * - user_data: If specified, this will be passed on to each call of the
158 * callback. The function will take ownership of the object, that is,
159 * increment the reference count by one. In case the caller does not longer
160 * use the object for other purposes, it should thus deref it.
161 *
162 * Returns:
163 * - 0 on success
164 * - a negative value else
165 */
166 int
167 sdb_plugin_register_collector(const char *name,
168 sdb_plugin_collector_cb callback,
169 const sdb_time_t *interval, sdb_object_t *user_data);
171 /*
172 * sdb_plugin_register_cname:
173 * Register a "cname" (canonicalize name) function. This type of function is
174 * called whenever a host is stored. It accepts the hostname and returns a
175 * canonicalized hostname which will then be used to actually store the host.
176 * If multiple such callbacks are registered, each one of them will be called
177 * in the order they have been registered, each one receiving the result of
178 * the previous callback. If the function returns NULL, the original hostname
179 * is not changed. Any other value has to be dynamically allocated. It will be
180 * freed later on by the core.
181 *
182 * Returns:
183 * - 0 on success
184 * - a negative value else
185 */
186 int
187 sdb_plugin_register_cname(const char *name, sdb_plugin_cname_cb callback,
188 sdb_object_t *user_data);
190 /*
191 * sdb_plugin_register_shutdown:
192 * Register a "shutdown" function to be called after stopping all update
193 * processes and before shutting down the daemon.
194 *
195 * Arguments:
196 * - user_data: If specified, this will be passed on to each call of the
197 * callback. The function will take ownership of the object, that is,
198 * increment the reference count by one. In case the caller does not longer
199 * use the object for other purposes, it should thus deref it.
200 */
201 int
202 sdb_plugin_register_shutdown(const char *name,
203 sdb_plugin_shutdown_cb callback,
204 sdb_object_t *user_data);
206 /*
207 * sdb_plugin_register_log:
208 * Register a "log" function to be called whenever logging is to be done.
209 *
210 * Arguments:
211 * - user_data: If specified, this will be passed on to each call of the
212 * callback. The function will take ownership of the object, that is,
213 * increment the reference count by one. In case the caller does not longer
214 * use the object for other purposes, it should thus deref it.
215 */
216 int
217 sdb_plugin_register_log(const char *name, sdb_plugin_log_cb callback,
218 sdb_object_t *user_data);
220 /*
221 * sdb_plugin_get_ctx, sdb_plugin_set_ctx:
222 * The plugin context defines a set of settings that are available whenever a
223 * plugin has been called. It may be used to pass around various information
224 * between the different component of the library without having each and
225 * every plugin care about it.
226 *
227 * If non-NULL, sdb_plugin_set_ctx stores the previous context in the location
228 * pointed to be 'old'.
229 */
230 sdb_plugin_ctx_t
231 sdb_plugin_get_ctx(void);
232 int
233 sdb_plugin_set_ctx(sdb_plugin_ctx_t ctx, sdb_plugin_ctx_t *old);
235 /*
236 * sdb_plugin_configure:
237 * Configure the plugin called 'name' (according to the registered config
238 * callback) using the config tree 'ci'.
239 *
240 * Returns:
241 * - 0 on success
242 * - a negative value else
243 */
244 int
245 sdb_plugin_configure(const char *name, oconfig_item_t *ci);
247 /*
248 * sdb_plugin_reconfigure_init, sdb_plugin_reconfigure_finish:
249 * Reconfigure all plugins. This happens in multiple steps: first, call
250 * sdb_plugin_reconfigure_init to deconfigure all plugins by calling their
251 * config callbacks with a NULL config tree and unregistering all callbacks.
252 * Then, sdb_plugin_configure and other functions may be used to provide the
253 * new configuration or load new plugins. For all plugins which were already
254 * loaded before, sdb_module_init will be called with a NULL argument when
255 * reloading them.
256 * Finally, sdb_plugin_reconfigure_finish will clean up leftover pieces, like
257 * unloading plugins which are no longer in use.
258 *
259 * Returns:
260 * - 0 on success
261 * - a negative value else
262 */
263 int
264 sdb_plugin_reconfigure_init(void);
265 int
266 sdb_plugin_reconfigure_finish(void);
268 /*
269 * sdb_plugin_init_all:
270 * Initialize all plugins using their registered "init" function.
271 *
272 * Returns:
273 * The number of failed initializations.
274 */
275 int
276 sdb_plugin_init_all(void);
278 /*
279 * sdb_plugin_shutdown_all:
280 * Shutdown all plugins using their registered "shutdown" function.
281 *
282 * Returns:
283 * The number of failed shutdowns.
284 */
285 int
286 sdb_plugin_shutdown_all(void);
288 /*
289 * sdb_plugin_collector_loop:
290 * Loop until loop->do_loop is false, calling the next collector function on
291 * each iteration and once its next update interval is passed.
292 *
293 * Returns:
294 * - 0 on success
295 * - a negative value else
296 */
297 int
298 sdb_plugin_collector_loop(sdb_plugin_loop_t *loop);
300 /*
301 * sdb_plugin_cname:
302 * Returns the canonicalized hostname. The given hostname argument has to
303 * point to dynamically allocated memory and might be freed by the function.
304 * The return value will also be dynamically allocated (but it might be
305 * unchanged) and has to be freed by the caller.
306 */
307 char *
308 sdb_plugin_cname(char *hostname);
310 /*
311 * sdb_plugin_log:
312 * Log the specified message using all registered log callbacks. The message
313 * will be logged with the specified priority.
314 */
315 int
316 sdb_plugin_log(int prio, const char *msg);
318 /*
319 * sdb_plugin_logf:
320 * Log a formatted message. See sdb_plugin_log for more information.
321 */
322 int
323 sdb_plugin_vlogf(int prio, const char *fmt, va_list ap);
324 int
325 sdb_plugin_logf(int prio, const char *fmt, ...);
327 #ifdef __cplusplus
328 } /* extern "C" */
329 #endif
331 #endif /* ! SDB_CORE_PLUGIN_H */
333 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */