a249cf7688b5f7b8c375cf0e34118e6642724b2a
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 /*
46 * Returns the number of plugins registered
47 */
48 int plugin_count (void)
49 {
50 int i;
51 plugin_t *p;
53 for (i = 0, p = first_plugin; p != NULL; p = p->next)
54 i++;
56 return (i);
57 }
59 /*
60 * Returns the plugins with the type `type' or NULL if it's not found.
61 */
62 plugin_t *plugin_search (char *type)
63 {
64 plugin_t *ret;
66 if (type == NULL)
67 return (NULL);
69 for (ret = first_plugin; ret != NULL; ret = ret->next)
70 if (strcmp (ret->type, type) == 0)
71 break;
73 return (ret);
74 }
76 /*
77 * Returns true if the plugin is loaded (i.e. `exists') and false otherwise.
78 * This is used in `configfile.c' to skip sections that are not needed..
79 */
80 bool plugin_exists (char *type)
81 {
82 if (plugin_search (type) == NULL)
83 return (false);
84 else
85 return (true);
86 }
88 /*
89 * (Try to) load the shared object `name'. Won't complain if it isn't a shared
90 * object, but it will bitch about a shared object not having a
91 * ``module_register'' symbol..
92 */
93 void plugin_load (char *name)
94 {
95 lt_dlhandle dlh;
96 void (*reg_handle) (void);
98 lt_dlinit ();
99 lt_dlerror (); /* clear errors */
101 if ((dlh = lt_dlopen (name)) == NULL)
102 return;
104 if ((reg_handle = lt_dlsym (dlh, "module_register")) == NULL)
105 {
106 syslog (LOG_WARNING, "Couldn't find symbol ``module_register'' in ``%s'': %s\n",
107 name, lt_dlerror ());
108 lt_dlclose (dlh);
109 return;
110 }
112 (*reg_handle) ();
113 }
115 /*
116 * (Try to) load all plugins in `dir'. Returns the number of loaded plugins..
117 */
118 #define BUFSIZE 512
119 int plugin_load_all (char *dir)
120 {
121 DIR *dh;
122 struct dirent *de;
123 char filename[BUFSIZE];
124 struct stat statbuf;
126 if (dir == NULL)
127 dir = PLUGINDIR;
129 if ((dh = opendir (dir)) == NULL)
130 {
131 fprintf (stderr, "Error: Cannot read plugin directory `%s'\n", dir);
132 return (0);
133 }
135 while ((de = readdir (dh)) != NULL)
136 {
137 if (snprintf (filename, BUFSIZE, "%s/%s", dir, de->d_name) >= BUFSIZE)
138 continue;
140 if (lstat (filename, &statbuf) == -1)
141 {
142 syslog (LOG_WARNING, "stat %s: %s", filename, strerror (errno));
143 continue;
144 }
145 else if (!S_ISREG (statbuf.st_mode))
146 {
147 continue;
148 }
150 plugin_load (filename);
151 }
153 closedir (dh);
155 return (plugin_count ());
156 }
157 #undef BUFSIZE
159 /*
160 * Call `init' on all plugins (if given)
161 */
162 void plugin_init_all (void)
163 {
164 plugin_t *p;
166 for (p = first_plugin; p != NULL; p = p->next)
167 if (p->init != NULL)
168 (*p->init) ();
169 }
171 /*
172 * Call `read' on all plugins (if given)
173 */
174 void plugin_read_all (void)
175 {
176 plugin_t *p;
178 for (p = first_plugin; p != NULL; p = p->next)
179 if (p->read != NULL)
180 (*p->read) ();
181 }
183 /*
184 * Add plugin to the linked list of registered plugins.
185 */
186 void plugin_register (char *type,
187 void (*init) (void),
188 void (*read) (void),
189 void (*write) (char *, char *, char *))
190 {
191 plugin_t *p;
193 if (plugin_search (type) != NULL)
194 return;
196 if ((p = (plugin_t *) malloc (sizeof (plugin_t))) == NULL)
197 return;
199 if ((p->type = strdup (type)) == NULL)
200 {
201 free (p);
202 return;
203 }
205 p->init = init;
206 p->read = read;
207 p->write = write;
209 p->next = first_plugin;
210 first_plugin = p;
211 }
213 /*
214 * Send received data back to the plugin/module which will append DS
215 * definitions and pass it on to ``rrd_update_file''.
216 */
217 #ifdef HAVE_LIBRRD
218 void plugin_write (char *host, char *type, char *inst, char *val)
219 {
220 plugin_t *p;
222 if ((p = plugin_search (type)) == NULL)
223 return;
225 if (p->write == NULL)
226 return;
228 (*p->write) (host, inst, val);
229 }
230 #endif /* HAVE_LIBRRD */
232 /*
233 * Receive data from the plugin/module and get it somehow to ``plugin_write'':
234 * Either using ``multicast_send'' (when in network/client mode) or call it
235 * directly (in local mode).
236 */
237 void plugin_submit (char *type, char *inst, char *val)
238 {
239 #ifdef HAVE_LIBRRD
240 if (operating_mode == MODE_LOCAL)
241 plugin_write (NULL, type, inst, val);
242 else if (operating_mode == MODE_CLIENT)
243 multicast_send (type, inst, val);
244 else /* operating_mode == MODE_SERVER */
245 syslog (LOG_ERR, "WTF is the server doing in ``plugin_submit''?!?\n");
246 #else
247 multicast_send (type, inst, val);
248 #endif
249 }