1 /**
2 * collectd - src/entropy.c
3 * Copyright (C) 2007 Florian octo Forster
4 *
5 * Permission is hereby granted, free of charge, to any person obtaining a
6 * copy of this software and associated documentation files (the "Software"),
7 * to deal in the Software without restriction, including without limitation
8 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
9 * and/or sell copies of the Software, and to permit persons to whom the
10 * Software is furnished to do so, subject to the following conditions:
11 *
12 * The above copyright notice and this permission notice shall be included in
13 * all copies or substantial portions of the Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
18 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
21 * DEALINGS IN THE SOFTWARE.
22 *
23 * Authors:
24 * Florian octo Forster <octo at collectd.org>
25 **/
27 #include "collectd.h"
29 #include "common.h"
30 #include "plugin.h"
32 #if !KERNEL_LINUX
33 #error "No applicable input method."
34 #endif
36 #define ENTROPY_FILE "/proc/sys/kernel/random/entropy_avail"
38 static void entropy_submit(double entropy) {
39 value_t values[1];
40 value_list_t vl = VALUE_LIST_INIT;
42 values[0].gauge = entropy;
44 vl.values = values;
45 vl.values_len = 1;
46 sstrncpy(vl.host, hostname_g, sizeof(vl.host));
47 sstrncpy(vl.plugin, "entropy", sizeof(vl.plugin));
48 sstrncpy(vl.type, "entropy", sizeof(vl.type));
50 plugin_dispatch_values(&vl);
51 }
53 static int entropy_read(void) {
54 double entropy;
55 FILE *fh;
56 char buffer[64];
58 fh = fopen(ENTROPY_FILE, "r");
59 if (fh == NULL)
60 return (-1);
62 if (fgets(buffer, sizeof(buffer), fh) == NULL) {
63 fclose(fh);
64 return (-1);
65 }
66 fclose(fh);
68 entropy = atof(buffer);
70 if (entropy > 0.0)
71 entropy_submit(entropy);
73 return (0);
74 }
76 void module_register(void) {
77 plugin_register_read("entropy", entropy_read);
78 } /* void module_register */