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"
28 #include "common.h"
29 #include "filter_chain.h"
31 /*
32 * private data types
33 */
34 struct mh_hash_match_s
35 {
36 uint32_t match;
37 uint32_t total;
38 };
39 typedef struct mh_hash_match_s mh_hash_match_t;
41 struct mh_match_s;
42 typedef struct mh_match_s mh_match_t;
43 struct mh_match_s
44 {
45 mh_hash_match_t *matches;
46 size_t matches_num;
47 };
49 /*
50 * internal helper functions
51 */
52 static int mh_config_match (const oconfig_item_t *ci, /* {{{ */
53 mh_match_t *m)
54 {
55 mh_hash_match_t *tmp;
57 if ((ci->values_num != 2)
58 || (ci->values[0].type != OCONFIG_TYPE_NUMBER)
59 || (ci->values[1].type != OCONFIG_TYPE_NUMBER))
60 {
61 ERROR ("hashed match: The `Match' option requires "
62 "exactly two numeric arguments.");
63 return (-1);
64 }
66 if ((ci->values[0].value.number < 0)
67 || (ci->values[1].value.number < 0))
68 {
69 ERROR ("hashed match: The arguments of the `Match' "
70 "option must be positive.");
71 return (-1);
72 }
74 tmp = realloc (m->matches, sizeof (*tmp) * (m->matches_num + 1));
75 if (tmp == NULL)
76 {
77 ERROR ("hashed match: realloc failed.");
78 return (-1);
79 }
80 m->matches = tmp;
81 tmp = m->matches + m->matches_num;
83 tmp->match = (uint32_t) (ci->values[0].value.number + .5);
84 tmp->total = (uint32_t) (ci->values[1].value.number + .5);
86 if (tmp->match >= tmp->total)
87 {
88 ERROR ("hashed match: The first argument of the `Match' option "
89 "must be smaller than the second argument.");
90 return (-1);
91 }
92 assert (tmp->total != 0);
94 m->matches_num++;
95 return (0);
96 } /* }}} int mh_config_match */
98 static int mh_create (const oconfig_item_t *ci, void **user_data) /* {{{ */
99 {
100 mh_match_t *m;
101 int i;
103 m = calloc (1, sizeof (*m));
104 if (m == NULL)
105 {
106 ERROR ("mh_create: calloc failed.");
107 return (-ENOMEM);
108 }
110 for (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;
152 const char *host_ptr;
153 size_t i;
155 if ((user_data == NULL) || (*user_data == NULL))
156 return (-1);
158 m = *user_data;
160 hash_val = 0;
162 for (host_ptr = vl->host; *host_ptr != 0; host_ptr++)
163 {
164 /* 2184401929 is some appropriately sized prime number. */
165 hash_val = (hash_val * UINT32_C (2184401929)) + ((uint32_t) *host_ptr);
166 }
167 DEBUG ("hashed match: host = %s; hash_val = %"PRIu32";", vl->host, hash_val);
169 for (i = 0; i < m->matches_num; i++)
170 if ((hash_val % m->matches[i].total) == m->matches[i].match)
171 return (FC_MATCH_MATCHES);
173 return (FC_MATCH_NO_MATCH);
174 } /* }}} int mh_match */
176 void module_register (void)
177 {
178 match_proc_t mproc;
180 memset (&mproc, 0, sizeof (mproc));
181 mproc.create = mh_create;
182 mproc.destroy = mh_destroy;
183 mproc.match = mh_match;
184 fc_register_match ("hashed", mproc);
185 } /* module_register */
187 /* vim: set sw=2 sts=2 tw=78 et fdm=marker : */