1 /**
2 * collectd - src/match_hashed.c
3 * Copyright (C) 2009 Florian 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 Forster <octo at collectd.org>
25 **/
27 #include "collectd.h"
29 #include "common.h"
30 #include "filter_chain.h"
32 /*
33 * private data types
34 */
35 struct mh_hash_match_s
36 {
37 uint32_t match;
38 uint32_t total;
39 };
40 typedef struct mh_hash_match_s mh_hash_match_t;
42 struct mh_match_s;
43 typedef struct mh_match_s mh_match_t;
44 struct mh_match_s
45 {
46 mh_hash_match_t *matches;
47 size_t matches_num;
48 };
50 /*
51 * internal helper functions
52 */
53 static int mh_config_match (const oconfig_item_t *ci, /* {{{ */
54 mh_match_t *m)
55 {
56 mh_hash_match_t *tmp;
58 if ((ci->values_num != 2)
59 || (ci->values[0].type != OCONFIG_TYPE_NUMBER)
60 || (ci->values[1].type != OCONFIG_TYPE_NUMBER))
61 {
62 ERROR ("hashed match: The `Match' option requires "
63 "exactly two numeric arguments.");
64 return (-1);
65 }
67 if ((ci->values[0].value.number < 0)
68 || (ci->values[1].value.number < 0))
69 {
70 ERROR ("hashed match: The arguments of the `Match' "
71 "option must be positive.");
72 return (-1);
73 }
75 tmp = realloc (m->matches, sizeof (*tmp) * (m->matches_num + 1));
76 if (tmp == NULL)
77 {
78 ERROR ("hashed match: realloc failed.");
79 return (-1);
80 }
81 m->matches = tmp;
82 tmp = m->matches + m->matches_num;
84 tmp->match = (uint32_t) (ci->values[0].value.number + .5);
85 tmp->total = (uint32_t) (ci->values[1].value.number + .5);
87 if (tmp->match >= tmp->total)
88 {
89 ERROR ("hashed match: The first argument of the `Match' option "
90 "must be smaller than the second argument.");
91 return (-1);
92 }
93 assert (tmp->total != 0);
95 m->matches_num++;
96 return (0);
97 } /* }}} int mh_config_match */
99 static int mh_create (const oconfig_item_t *ci, void **user_data) /* {{{ */
100 {
101 mh_match_t *m;
103 m = calloc (1, sizeof (*m));
104 if (m == NULL)
105 {
106 ERROR ("mh_create: calloc failed.");
107 return (-ENOMEM);
108 }
110 for (int i = 0; i < ci->children_num; i++)
111 {
112 oconfig_item_t *child = ci->children + i;
114 if (strcasecmp ("Match", child->key) == 0)
115 mh_config_match (child, m);
116 else
117 ERROR ("hashed match: No such config option: %s", child->key);
118 }
120 if (m->matches_num == 0)
121 {
122 sfree (m->matches);
123 sfree (m);
124 ERROR ("hashed match: No matches were configured. Not creating match.");
125 return (-1);
126 }
128 *user_data = m;
129 return (0);
130 } /* }}} int mh_create */
132 static int mh_destroy (void **user_data) /* {{{ */
133 {
134 mh_match_t *mh;
136 if ((user_data == NULL) || (*user_data == NULL))
137 return (0);
139 mh = *user_data;
140 sfree (mh->matches);
141 sfree (mh);
143 return (0);
144 } /* }}} int mh_destroy */
146 static int mh_match (const data_set_t __attribute__((unused)) *ds, /* {{{ */
147 const value_list_t *vl,
148 notification_meta_t __attribute__((unused)) **meta, void **user_data)
149 {
150 mh_match_t *m;
151 uint32_t hash_val;
153 if ((user_data == NULL) || (*user_data == NULL))
154 return (-1);
156 m = *user_data;
158 hash_val = 0;
160 for (const char *host_ptr = vl->host; *host_ptr != 0; host_ptr++)
161 {
162 /* 2184401929 is some appropriately sized prime number. */
163 hash_val = (hash_val * UINT32_C (2184401929)) + ((uint32_t) *host_ptr);
164 }
165 DEBUG ("hashed match: host = %s; hash_val = %"PRIu32";", vl->host, hash_val);
167 for (size_t i = 0; i < m->matches_num; i++)
168 if ((hash_val % m->matches[i].total) == m->matches[i].match)
169 return (FC_MATCH_MATCHES);
171 return (FC_MATCH_NO_MATCH);
172 } /* }}} int mh_match */
174 void module_register (void)
175 {
176 match_proc_t mproc = { 0 };
178 mproc.create = mh_create;
179 mproc.destroy = mh_destroy;
180 mproc.match = mh_match;
181 fc_register_match ("hashed", mproc);
182 } /* module_register */
184 /* vim: set sw=2 sts=2 tw=78 et fdm=marker : */