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.
68 */
69 int
70 sdb_plugin_load(const char *name, const sdb_plugin_ctx_t *plugin_ctx);
72 /*
73 * sdb_plugin_set_info:
74 * Fill in the fields of the sdb_plugin_info_t object passed to the
75 * sdb_module_init function. This information is used to identify the plugin
76 * and also to provide additional information to the user.
77 */
78 enum {
79 SDB_PLUGIN_INFO_NAME, /* plugin name: string */
80 SDB_PLUGIN_INFO_DESC, /* plugin description: string */
81 SDB_PLUGIN_INFO_COPYRIGHT, /* plugin copyright: string */
82 SDB_PLUGIN_INFO_LICENSE, /* plugin license: string */
83 SDB_PLUGIN_INFO_VERSION, /* libsysdb version: integer */
84 SDB_PLUGIN_INFO_PLUGIN_VERSION /* plugin version: integer */
85 };
87 int
88 sdb_plugin_set_info(sdb_plugin_info_t *info, int type, ...);
90 /*
91 * plugin callback functions:
92 * See the description of the respective register function for what arguments
93 * the callbacks expect.
94 */
96 typedef int (*sdb_plugin_config_cb)(oconfig_item_t *ci);
97 typedef int (*sdb_plugin_init_cb)(sdb_object_t *user_data);
98 typedef int (*sdb_plugin_collector_cb)(sdb_object_t *user_data);
99 typedef char *(*sdb_plugin_cname_cb)(const char *name,
100 sdb_object_t *user_data);
101 typedef int (*sdb_plugin_shutdown_cb)(sdb_object_t *user_data);
102 typedef int (*sdb_plugin_log_cb)(int prio, const char *msg,
103 sdb_object_t *user_data);
105 /*
106 * sdb_plugin_register_config:
107 * Register a "config" function. This will be used to pass on the
108 * configuration for a plugin. The plugin has to make sure that the function
109 * can be called multiple times in order to process multiple <Plugin> blocks
110 * specified in the configuration file(s).
111 *
112 * Returns:
113 * - 0 on success
114 * - a negative value else
115 */
116 int
117 sdb_plugin_register_config(const char *name, sdb_plugin_config_cb callback);
119 /*
120 * sdb_plugin_register_init:
121 * Register an "init" function. All "init" functions will be called after
122 * finishing the config parsing and before starting any other work. The
123 * functions will be called in the same order as they have been registered,
124 * that is, functions of different plugins will be called in the same order as
125 * the appropriate "Load" statements in the config file.
126 *
127 * If the "init" function returns a non-zero value, *all* callbacks of the
128 * plugin will be unloaded.
129 *
130 * Arguments:
131 * - user_data: If specified, this will be passed on to each call of the
132 * callback. The function will take ownership of the object, that is,
133 * increment the reference count by one. In case the caller does not longer
134 * use the object for other purposes, it should thus deref it.
135 *
136 * Returns:
137 * - 0 on success
138 * - a negative value else
139 */
140 int
141 sdb_plugin_register_init(const char *name, sdb_plugin_init_cb callback,
142 sdb_object_t *user_data);
144 /*
145 * sdb_plugin_register_collector:
146 * Register a "collector" function. This is where a backend is doing its main
147 * work. This function will be called whenever an update of a backend has been
148 * requested (either by regular interval or by user request). The backend
149 * should then query the appropriate data-source and submit all values to the
150 * core.
151 *
152 * Arguments:
153 * - interval: Specifies the regular interval at which to update the backend.
154 * If this is NULL, global settings will be used.
155 * - user_data: If specified, this will be passed on to each call of the
156 * callback. The function will take ownership of the object, that is,
157 * increment the reference count by one. In case the caller does not longer
158 * use the object for other purposes, it should thus deref it.
159 *
160 * Returns:
161 * - 0 on success
162 * - a negative value else
163 */
164 int
165 sdb_plugin_register_collector(const char *name,
166 sdb_plugin_collector_cb callback,
167 const sdb_time_t *interval, sdb_object_t *user_data);
169 /*
170 * sdb_plugin_register_cname:
171 * Register a "cname" (canonicalize name) function. This type of function is
172 * called whenever a host is stored. It accepts the hostname and returns a
173 * canonicalized hostname which will then be used to actually store the host.
174 * If multiple such callbacks are registered, each one of them will be called
175 * in the order they have been registered, each one receiving the result of
176 * the previous callback. If the function returns NULL, the original hostname
177 * is not changed. Any other value has to be dynamically allocated. It will be
178 * freed later on by the core.
179 *
180 * Returns:
181 * - 0 on success
182 * - a negative value else
183 */
184 int
185 sdb_plugin_register_cname(const char *name, sdb_plugin_cname_cb callback,
186 sdb_object_t *user_data);
188 /*
189 * sdb_plugin_register_shutdown:
190 * Register a "shutdown" function to be called after stopping all update
191 * processes and before shutting down the daemon.
192 *
193 * Arguments:
194 * - user_data: If specified, this will be passed on to each call of the
195 * callback. The function will take ownership of the object, that is,
196 * increment the reference count by one. In case the caller does not longer
197 * use the object for other purposes, it should thus deref it.
198 */
199 int
200 sdb_plugin_register_shutdown(const char *name,
201 sdb_plugin_shutdown_cb callback,
202 sdb_object_t *user_data);
204 /*
205 * sdb_plugin_register_log:
206 * Register a "log" function to be called whenever logging is to be done.
207 *
208 * Arguments:
209 * - user_data: If specified, this will be passed on to each call of the
210 * callback. The function will take ownership of the object, that is,
211 * increment the reference count by one. In case the caller does not longer
212 * use the object for other purposes, it should thus deref it.
213 */
214 int
215 sdb_plugin_register_log(const char *name, sdb_plugin_log_cb callback,
216 sdb_object_t *user_data);
218 /*
219 * sdb_plugin_get_ctx, sdb_plugin_set_ctx:
220 * The plugin context defines a set of settings that are available whenever a
221 * plugin has been called. It may be used to pass around various information
222 * between the different component of the library without having each and
223 * every plugin care about it.
224 *
225 * If non-NULL, sdb_plugin_set_ctx stores the previous context in the location
226 * pointed to be 'old'.
227 */
228 sdb_plugin_ctx_t
229 sdb_plugin_get_ctx(void);
230 int
231 sdb_plugin_set_ctx(sdb_plugin_ctx_t ctx, sdb_plugin_ctx_t *old);
233 /*
234 * sdb_plugin_configure:
235 * Configure the plugin called 'name' (according to the registered config
236 * callback) using the config tree 'ci'.
237 *
238 * Returns:
239 * - 0 on success
240 * - a negative value else
241 */
242 int
243 sdb_plugin_configure(const char *name, oconfig_item_t *ci);
245 /*
246 * sdb_plugin_init_all:
247 * Initialize all plugins using their registered "init" function.
248 *
249 * Returns:
250 * The number of failed initializations.
251 */
252 int
253 sdb_plugin_init_all(void);
255 /*
256 * sdb_plugin_collector_loop:
257 * Loop until loop->do_loop is false, calling the next collector function on
258 * each iteration and once its next update interval is passed.
259 *
260 * Returns:
261 * - 0 on success
262 * - a negative value else
263 */
264 int
265 sdb_plugin_collector_loop(sdb_plugin_loop_t *loop);
267 /*
268 * sdb_plugin_cname:
269 * Returns the canonicalized hostname. The given hostname argument has to
270 * point to dynamically allocated memory and might be freed by the function.
271 * The return value will also be dynamically allocated (but it might be
272 * unchanged) and has to be freed by the caller.
273 */
274 char *
275 sdb_plugin_cname(char *hostname);
277 /*
278 * sdb_plugin_log:
279 * Log the specified message using all registered log callbacks. The message
280 * will be logged with the specified priority.
281 */
282 int
283 sdb_plugin_log(int prio, const char *msg);
285 /*
286 * sdb_plugin_logf:
287 * Log a formatted message. See sdb_plugin_log for more information.
288 */
289 int
290 sdb_plugin_vlogf(int prio, const char *fmt, va_list ap);
291 int
292 sdb_plugin_logf(int prio, const char *fmt, ...);
294 #ifdef __cplusplus
295 } /* extern "C" */
296 #endif
298 #endif /* ! SDB_CORE_PLUGIN_H */
300 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */