1 /**
2 * collectd - src/plugin.c
3 * Copyright (C) 2005 Florian octo Forster
4 *
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License as published by the
7 * Free Software Foundation; either version 2 of the License, or (at your
8 * option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License along
16 * with this program; if not, write to the Free Software Foundation, Inc.,
17 * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
18 *
19 * Authors:
20 * Florian octo Forster <octo at verplant.org>
21 **/
23 #include "collectd.h"
25 #include <ltdl.h>
27 #include "plugin.h"
28 #include "multicast.h"
30 typedef struct plugin
31 {
32 char *type;
33 void (*init) (void);
34 void (*read) (void);
35 void (*write) (char *host, char *inst, char *val);
36 struct plugin *next;
37 } plugin_t;
39 static plugin_t *first_plugin = NULL;
41 #ifdef HAVE_LIBRRD
42 extern int operating_mode;
43 #endif
45 static char *plugindir = NULL;
47 char *plugin_get_dir (void)
48 {
49 if (plugindir == NULL)
50 return (PLUGINDIR);
51 else
52 return (plugindir);
53 }
55 void plugin_set_dir (const char *dir)
56 {
57 if (plugindir != NULL)
58 free (plugindir);
60 if (dir == NULL)
61 plugindir = NULL;
62 else if ((plugindir = strdup (dir)) == NULL)
63 syslog (LOG_ERR, "strdup: %s", strerror (errno));
64 }
66 /*
67 * Returns the number of plugins registered
68 */
69 int plugin_count (void)
70 {
71 int i;
72 plugin_t *p;
74 for (i = 0, p = first_plugin; p != NULL; p = p->next)
75 i++;
77 return (i);
78 }
80 /*
81 * Returns the plugins with the type `type' or NULL if it's not found.
82 */
83 plugin_t *plugin_search (const char *type)
84 {
85 plugin_t *ret;
87 if (type == NULL)
88 return (NULL);
90 for (ret = first_plugin; ret != NULL; ret = ret->next)
91 if (strcmp (ret->type, type) == 0)
92 break;
94 return (ret);
95 }
97 /*
98 * Returns true if the plugin is loaded (i.e. `exists') and false otherwise.
99 * This is used in `configfile.c' to skip sections that are not needed..
100 */
101 int plugin_exists (char *type)
102 {
103 if (plugin_search (type) == NULL)
104 return (0);
105 else
106 return (1);
107 }
109 /*
110 * (Try to) load the shared object `file'. Won't complain if it isn't a shared
111 * object, but it will bitch about a shared object not having a
112 * ``module_register'' symbol..
113 */
114 int plugin_load_file (char *file)
115 {
116 lt_dlhandle dlh;
117 void (*reg_handle) (void);
119 lt_dlinit ();
120 lt_dlerror (); /* clear errors */
122 if ((dlh = lt_dlopen (file)) == NULL)
123 return (1);
125 if ((reg_handle = lt_dlsym (dlh, "module_register")) == NULL)
126 {
127 syslog (LOG_WARNING, "Couldn't find symbol ``module_register'' in ``%s'': %s\n",
128 file, lt_dlerror ());
129 lt_dlclose (dlh);
130 return (-1);
131 }
133 (*reg_handle) ();
135 return (0);
136 }
138 #define BUFSIZE 512
139 int plugin_load (const char *type)
140 {
141 DIR *dh;
142 char *dir;
143 char filename[BUFSIZE];
144 char typename[BUFSIZE];
145 int typename_len;
146 int ret;
147 struct stat statbuf;
148 struct dirent *de;
150 dir = plugin_get_dir ();
151 ret = 1;
153 /* don't load twice */
154 if (plugin_search (type) != NULL)
155 return (0);
157 /* `cpu' should not match `cpufreq'. To solve this we add `.so' to the
158 * type when matching the filename */
159 if (snprintf (typename, BUFSIZE, "%s.so", type) >= BUFSIZE)
160 {
161 syslog (LOG_WARNING, "snprintf: truncated: `%s.so'", type);
162 return (-1);
163 }
164 typename_len = strlen (typename);
166 if ((dh = opendir (dir)) == NULL)
167 {
168 syslog (LOG_ERR, "opendir (%s): %s", dir, strerror (errno));
169 return (-1);
170 }
172 while ((de = readdir (dh)) != NULL)
173 {
174 if (strncasecmp (de->d_name, typename, typename_len))
175 continue;
177 if (snprintf (filename, BUFSIZE, "%s/%s", dir, de->d_name) >= BUFSIZE)
178 {
179 syslog (LOG_WARNING, "snprintf: truncated: `%s/%s'", dir, de->d_name);
180 continue;
181 }
183 if (lstat (filename, &statbuf) == -1)
184 {
185 syslog (LOG_WARNING, "stat %s: %s", filename, strerror (errno));
186 continue;
187 }
188 else if (!S_ISREG (statbuf.st_mode))
189 {
190 /* don't follow symlinks */
191 continue;
192 }
194 if (plugin_load_file (filename) == 0)
195 {
196 /* success */
197 ret = 0;
198 break;
199 }
200 }
202 closedir (dh);
204 return (ret);
205 }
207 /*
208 * (Try to) load all plugins in `dir'. Returns the number of loaded plugins..
209 */
210 int plugin_load_all (char *dir)
211 {
212 DIR *dh;
213 struct dirent *de;
214 char filename[BUFSIZE];
215 struct stat statbuf;
217 if (dir == NULL)
218 dir = plugin_get_dir ();
219 else
220 plugin_set_dir (dir);
222 if ((dh = opendir (dir)) == NULL)
223 {
224 syslog (LOG_ERR, "opendir (%s): %s", dir, strerror (errno));
225 return (0);
226 }
228 while ((de = readdir (dh)) != NULL)
229 {
230 if (snprintf (filename, BUFSIZE, "%s/%s", dir, de->d_name) >= BUFSIZE)
231 {
232 syslog (LOG_WARNING, "snprintf: truncated: %s/%s", dir, de->d_name);
233 continue;
234 }
236 if (lstat (filename, &statbuf) == -1)
237 {
238 syslog (LOG_WARNING, "stat %s: %s", filename, strerror (errno));
239 continue;
240 }
241 else if (!S_ISREG (statbuf.st_mode))
242 {
243 continue;
244 }
246 plugin_load_file (filename);
247 }
249 closedir (dh);
251 return (plugin_count ());
252 }
253 #undef BUFSIZE
255 /*
256 * Call `init' on all plugins (if given)
257 */
258 void plugin_init_all (void)
259 {
260 plugin_t *p;
262 for (p = first_plugin; p != NULL; p = p->next)
263 if (p->init != NULL)
264 (*p->init) ();
265 }
267 /*
268 * Call `read' on all plugins (if given)
269 */
270 void plugin_read_all (void)
271 {
272 plugin_t *p;
274 for (p = first_plugin; p != NULL; p = p->next)
275 if (p->read != NULL)
276 (*p->read) ();
277 }
279 /*
280 * Add plugin to the linked list of registered plugins.
281 */
282 void plugin_register (char *type,
283 void (*init) (void),
284 void (*read) (void),
285 void (*write) (char *, char *, char *))
286 {
287 plugin_t *p;
289 if (plugin_search (type) != NULL)
290 return;
292 #ifdef HAVE_LIBRRD
293 if ((operating_mode == MODE_LOCAL) || (operating_mode == MODE_CLIENT))
294 #endif
295 if ((init != NULL) && (read == NULL))
296 syslog (LOG_NOTICE, "Plugin `%s' doesn't provide a read function.", type);
298 if ((p = (plugin_t *) malloc (sizeof (plugin_t))) == NULL)
299 return;
301 if ((p->type = strdup (type)) == NULL)
302 {
303 free (p);
304 return;
305 }
307 p->init = init;
308 p->read = read;
309 p->write = write;
311 p->next = first_plugin;
312 first_plugin = p;
313 }
315 /*
316 * Send received data back to the plugin/module which will append DS
317 * definitions and pass it on to ``rrd_update_file''.
318 */
319 #ifdef HAVE_LIBRRD
320 void plugin_write (char *host, char *type, char *inst, char *val)
321 {
322 plugin_t *p;
324 if ((p = plugin_search (type)) == NULL)
325 return;
327 if (p->write == NULL)
328 return;
330 (*p->write) (host, inst, val);
331 }
332 #endif /* HAVE_LIBRRD */
334 /*
335 * Receive data from the plugin/module and get it somehow to ``plugin_write'':
336 * Either using ``multicast_send'' (when in network/client mode) or call it
337 * directly (in local mode).
338 */
339 void plugin_submit (char *type, char *inst, char *val)
340 {
341 #ifdef HAVE_LIBRRD
342 if (operating_mode == MODE_LOCAL)
343 plugin_write (NULL, type, inst, val);
344 else if (operating_mode == MODE_CLIENT)
345 multicast_send (type, inst, val);
346 else /* operating_mode == MODE_SERVER */
347 syslog (LOG_ERR, "WTF is the server doing in ``plugin_submit''?!?\n");
348 #else
349 multicast_send (type, inst, val);
350 #endif
351 }