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.
67 */
68 int
69 sdb_plugin_load(const char *name);
71 /*
72 * sdb_plugin_set_info:
73 * Fill in the fields of the sdb_plugin_info_t object passed to the
74 * sdb_module_init function. This information is used to identify the plugin
75 * and also to provide additional information to the user.
76 */
77 enum {
78 SDB_PLUGIN_INFO_NAME, /* plugin name: string */
79 SDB_PLUGIN_INFO_DESC, /* plugin description: string */
80 SDB_PLUGIN_INFO_COPYRIGHT, /* plugin copyright: string */
81 SDB_PLUGIN_INFO_LICENSE, /* plugin license: string */
82 SDB_PLUGIN_INFO_VERSION, /* libsysdb version: integer */
83 SDB_PLUGIN_INFO_PLUGIN_VERSION /* plugin version: integer */
84 };
86 int
87 sdb_plugin_set_info(sdb_plugin_info_t *info, int type, ...);
89 /*
90 * plugin callback functions:
91 * See the description of the respective register function for what arguments
92 * the callbacks expect.
93 */
95 typedef int (*sdb_plugin_config_cb)(oconfig_item_t *ci);
96 typedef int (*sdb_plugin_init_cb)(sdb_object_t *user_data);
97 typedef int (*sdb_plugin_collector_cb)(sdb_object_t *user_data);
98 typedef char *(*sdb_plugin_cname_cb)(const char *name,
99 sdb_object_t *user_data);
100 typedef int (*sdb_plugin_shutdown_cb)(sdb_object_t *user_data);
101 typedef int (*sdb_plugin_log_cb)(int prio, const char *msg,
102 sdb_object_t *user_data);
104 /*
105 * sdb_plugin_register_config:
106 * Register a "config" function. This will be used to pass on the
107 * configuration for a plugin. The plugin has to make sure that the function
108 * can be called multiple times in order to process multiple <Plugin> blocks
109 * specified in the configuration file(s).
110 *
111 * Returns:
112 * - 0 on success
113 * - a negative value else
114 */
115 int
116 sdb_plugin_register_config(const char *name, sdb_plugin_config_cb callback);
118 /*
119 * sdb_plugin_register_init:
120 * Register an "init" function. All "init" functions will be called after
121 * finishing the config parsing and before starting any other work. The
122 * functions will be called in the same order as they have been registered,
123 * that is, functions of different plugins will be called in the same order as
124 * the appropriate "Load" statements in the config file.
125 *
126 * If the "init" function returns a non-zero value, *all* callbacks of the
127 * plugin will be unloaded.
128 *
129 * Arguments:
130 * - user_data: If specified, this will be passed on to each call of the
131 * callback. The function will take ownership of the object, that is,
132 * increment the reference count by one. In case the caller does not longer
133 * use the object for other purposes, it should thus deref it.
134 *
135 * Returns:
136 * - 0 on success
137 * - a negative value else
138 */
139 int
140 sdb_plugin_register_init(const char *name, sdb_plugin_init_cb callback,
141 sdb_object_t *user_data);
143 /*
144 * sdb_plugin_register_collector:
145 * Register a "collector" function. This is where a backend is doing its main
146 * work. This function will be called whenever an update of a backend has been
147 * requested (either by regular interval or by user request). The backend
148 * should then query the appropriate data-source and submit all values to the
149 * core.
150 *
151 * Arguments:
152 * - interval: Specifies the regular interval at which to update the backend.
153 * If this is NULL, global settings will be used.
154 * - user_data: If specified, this will be passed on to each call of the
155 * callback. The function will take ownership of the object, that is,
156 * increment the reference count by one. In case the caller does not longer
157 * use the object for other purposes, it should thus deref it.
158 *
159 * Returns:
160 * - 0 on success
161 * - a negative value else
162 */
163 int
164 sdb_plugin_register_collector(const char *name,
165 sdb_plugin_collector_cb callback,
166 const sdb_time_t *interval, sdb_object_t *user_data);
168 /*
169 * sdb_plugin_register_cname:
170 * Register a "cname" (canonicalize name) function. This type of function is
171 * called whenever a host is stored. It accepts the hostname and returns a
172 * canonicalized hostname which will then be used to actually store the host.
173 * If multiple such callbacks are registered, each one of them will be called
174 * in the order they have been registered, each one receiving the result of
175 * the previous callback. If the function returns NULL, the original hostname
176 * is not changed. Any other value has to be dynamically allocated. It will be
177 * freed later on by the core.
178 *
179 * Returns:
180 * - 0 on success
181 * - a negative value else
182 */
183 int
184 sdb_plugin_register_cname(const char *name, sdb_plugin_cname_cb callback,
185 sdb_object_t *user_data);
187 /*
188 * sdb_plugin_register_shutdown:
189 * Register a "shutdown" function to be called after stopping all update
190 * processes and before shutting down the daemon.
191 *
192 * Arguments:
193 * - user_data: If specified, this will be passed on to each call of the
194 * callback. The function will take ownership of the object, that is,
195 * increment the reference count by one. In case the caller does not longer
196 * use the object for other purposes, it should thus deref it.
197 */
198 int
199 sdb_plugin_register_shutdown(const char *name,
200 sdb_plugin_shutdown_cb callback,
201 sdb_object_t *user_data);
203 /*
204 * sdb_plugin_register_log:
205 * Register a "log" function to be called whenever logging is to be done.
206 *
207 * Arguments:
208 * - user_data: If specified, this will be passed on to each call of the
209 * callback. The function will take ownership of the object, that is,
210 * increment the reference count by one. In case the caller does not longer
211 * use the object for other purposes, it should thus deref it.
212 */
213 int
214 sdb_plugin_register_log(const char *name, sdb_plugin_log_cb callback,
215 sdb_object_t *user_data);
217 /*
218 * sdb_plugin_get_ctx, sdb_plugin_set_ctx:
219 * The plugin context defines a set of settings that are available whenever a
220 * plugin has been called. It may be used to pass around various information
221 * between the different component of the library without having each and
222 * every plugin care about it.
223 */
224 sdb_plugin_ctx_t
225 sdb_plugin_get_ctx(void);
226 sdb_plugin_ctx_t
227 sdb_plugin_set_ctx(sdb_plugin_ctx_t ctx);
229 /*
230 * sdb_plugin_configure:
231 * Configure the plugin called 'name' (according to the registered config
232 * callback) using the config tree 'ci'.
233 *
234 * Returns:
235 * - 0 on success
236 * - a negative value else
237 */
238 int
239 sdb_plugin_configure(const char *name, oconfig_item_t *ci);
241 /*
242 * sdb_plugin_init_all:
243 * Initialize all plugins using their registered "init" function.
244 */
245 int
246 sdb_plugin_init_all(void);
248 /*
249 * sdb_plugin_collector_loop:
250 * Loop until loop->do_loop is false, calling the next collector function on
251 * each iteration and once its next update interval is passed.
252 *
253 * Returns:
254 * - 0 on success
255 * - a negative value else
256 */
257 int
258 sdb_plugin_collector_loop(sdb_plugin_loop_t *loop);
260 /*
261 * sdb_plugin_cname:
262 * Returns the canonicalized hostname. The given hostname argument has to
263 * point to dynamically allocated memory and might be freed by the function.
264 * The return value will also be dynamically allocated (but it might be
265 * unchanged) and has to be freed by the caller.
266 */
267 char *
268 sdb_plugin_cname(char *hostname);
270 /*
271 * sdb_plugin_log:
272 * Log the specified message using all registered log callbacks. The message
273 * will be logged with the specified priority.
274 */
275 int
276 sdb_plugin_log(int prio, const char *msg);
278 /*
279 * sdb_plugin_logf:
280 * Log a formatted message. See sdb_plugin_log for more information.
281 */
282 int
283 sdb_plugin_vlogf(int prio, const char *fmt, va_list ap);
284 int
285 sdb_plugin_logf(int prio, const char *fmt, ...);
287 #ifdef __cplusplus
288 } /* extern "C" */
289 #endif
291 #endif /* ! SDB_CORE_PLUGIN_H */
293 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */