36cea0fb4b4618826cdb7e13af49f4f1b9f6daca
1 /*
2 * users.c
3 *
4 * users plugin for collectd
5 *
6 * This plugin collects the number of users currently logged into the system.
7 *
8 * Written by Sebastian Harl <sh@tokkee.org>
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; either version 2 of the License, or
13 * (at your option) any later version.
14 *
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
23 */
25 #include "users.h"
27 #if COLLECT_USERS
28 #define MODULE_NAME "users"
30 #include "plugin.h"
31 #include "common.h"
33 #include <utmpx.h>
35 static char *rrd_file = "users.rrd";
37 static char *ds_def[] = {
38 "DS:users:GAUGE:25:0:65535",
39 NULL
40 };
41 static int ds_num = 1;
43 extern time_t curtime;
45 void users_init(void)
46 {
47 /* we have nothing to do here :-) */
48 return;
49 }
51 void users_read(void)
52 {
53 unsigned int users = 0;
54 struct utmpx *entry = NULL;
56 /* according to the *utent(3) man page none of the functions sets errno in
57 * case of an error, so we cannot do any error-checking here */
58 setutxent();
60 while (NULL != (entry = getutxent()))
61 if (USER_PROCESS == entry->ut_type)
62 ++users;
63 endutxent();
65 users_submit(users);
66 return;
67 }
69 /* I don't like this temporary macro definition - well it's used everywhere
70 * else in the collectd-sources, so I will just stick with it... */
71 #define BUFSIZE 256
72 void users_submit(users)
73 unsigned int users;
74 {
75 char buf[BUFSIZE] = "";
77 if (snprintf(buf, BUFSIZE, "%u:%u",
78 (unsigned int)curtime,
79 users) >= BUFSIZE)
80 return;
82 plugin_submit(MODULE_NAME, NULL, buf);
83 return;
84 }
85 #undef BUFSIZE
87 void users_write(host, inst, val)
88 char *host;
89 char *inst;
90 char *val;
91 {
92 rrd_update_file(host, rrd_file, val, ds_def, ds_num);
93 return;
94 }
96 void module_register(void)
97 {
98 plugin_register(MODULE_NAME, users_init, users_read, users_write);
99 return;
100 }
102 #undef MODULE_NAME
103 #endif /* COLLECT_USERS */