d980f58605c1750d3451d7647b3f50fdbd5f03ee
1 /**
2 * collectd - src/utils_fbhash.c
3 * Copyright (C) 2009 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"
28 #include "plugin.h"
30 #include "utils_fbhash.h"
31 #include "utils_avltree.h"
33 struct fbhash_s
34 {
35 char *filename;
36 time_t mtime;
38 pthread_mutex_t lock;
39 c_avl_tree_t *tree;
40 };
42 /*
43 * Private functions
44 */
45 static void fbh_free_tree (c_avl_tree_t *tree) /* {{{ */
46 {
47 int status;
49 if (tree == NULL)
50 return;
52 while (42)
53 {
54 char *key = NULL;
55 char *value = NULL;
57 status = c_avl_pick (tree, (void *) &key, (void *) &value);
58 if (status != 0)
59 break;
61 free (key);
62 free (value);
63 }
65 c_avl_destroy (tree);
66 } /* }}} void fbh_free_tree */
68 static int fbh_read_file (fbhash_t *h) /* {{{ */
69 {
70 FILE *fh;
71 char buffer[4096];
72 struct flock fl = { 0 };
73 c_avl_tree_t *tree;
74 int status;
76 fh = fopen (h->filename, "r");
77 if (fh == NULL)
78 return (-1);
80 fl.l_type = F_RDLCK;
81 fl.l_whence = SEEK_SET;
82 /* TODO: Lock file? -> fcntl */
84 status = fcntl (fileno (fh), F_SETLK, &fl);
85 if (status != 0)
86 {
87 fclose (fh);
88 return (-1);
89 }
91 tree = c_avl_create ((int (*) (const void *, const void *)) strcmp);
92 if (tree == NULL)
93 {
94 fclose (fh);
95 return (-1);
96 }
98 /* Read `fh' into `tree' */
99 while (fgets (buffer, sizeof (buffer), fh) != NULL) /* {{{ */
100 {
101 size_t len;
102 char *key;
103 char *value;
105 char *key_copy;
106 char *value_copy;
108 buffer[sizeof (buffer) - 1] = 0;
109 len = strlen (buffer);
111 /* Remove trailing newline characters. */
112 while ((len > 0)
113 && ((buffer[len - 1] == '\n') || (buffer[len - 1] == '\r')))
114 {
115 len--;
116 buffer[len] = 0;
117 }
119 /* Seek first non-space character */
120 key = buffer;
121 while ((*key != 0) && isspace ((int) *key))
122 key++;
124 /* Skip empty lines and comments */
125 if ((key[0] == 0) || (key[0] == '#'))
126 continue;
128 /* Seek first colon */
129 value = strchr (key, ':');
130 if (value == NULL)
131 continue;
133 /* Null-terminate `key'. */
134 *value = 0;
135 value++;
137 /* Skip leading whitespace */
138 while ((*value != 0) && isspace ((int) *value))
139 value++;
141 /* Skip lines without value */
142 if (value[0] == 0)
143 continue;
145 key_copy = strdup (key);
146 value_copy = strdup (value);
148 if ((key_copy == NULL) || (value_copy == NULL))
149 {
150 free (key_copy);
151 free (value_copy);
152 continue;
153 }
155 status = c_avl_insert (tree, key_copy, value_copy);
156 if (status != 0)
157 {
158 free (key_copy);
159 free (value_copy);
160 continue;
161 }
163 DEBUG ("utils_fbhash: fbh_read_file: key = %s; value = %s;",
164 key, value);
165 } /* }}} while (fgets) */
167 fclose (fh);
169 fbh_free_tree (h->tree);
170 h->tree = tree;
172 return (0);
173 } /* }}} int fbh_read_file */
175 static int fbh_check_file (fbhash_t *h) /* {{{ */
176 {
177 struct stat statbuf = { 0 };
178 int status;
180 status = stat (h->filename, &statbuf);
181 if (status != 0)
182 return (-1);
184 if (h->mtime >= statbuf.st_mtime)
185 return (0);
187 status = fbh_read_file (h);
188 if (status == 0)
189 h->mtime = statbuf.st_mtime;
191 return (status);
192 } /* }}} int fbh_check_file */
194 /*
195 * Public functions
196 */
197 fbhash_t *fbh_create (const char *file) /* {{{ */
198 {
199 fbhash_t *h;
200 int status;
202 if (file == NULL)
203 return (NULL);
205 h = calloc (1, sizeof (*h));
206 if (h == NULL)
207 return (NULL);
209 h->filename = strdup (file);
210 if (h->filename == NULL)
211 {
212 free (h);
213 return (NULL);
214 }
216 h->mtime = 0;
217 pthread_mutex_init (&h->lock, /* attr = */ NULL);
219 status = fbh_check_file (h);
220 if (status != 0)
221 {
222 fbh_destroy (h);
223 free (h);
224 return (NULL);
225 }
227 return (h);
228 } /* }}} fbhash_t *fbh_create */
230 void fbh_destroy (fbhash_t *h) /* {{{ */
231 {
232 if (h == NULL)
233 return;
235 pthread_mutex_destroy (&h->lock);
236 free (h->filename);
237 fbh_free_tree (h->tree);
238 } /* }}} void fbh_destroy */
240 char *fbh_get (fbhash_t *h, const char *key) /* {{{ */
241 {
242 char *value;
243 char *value_copy;
244 int status;
246 if ((h == NULL) || (key == NULL))
247 return (NULL);
249 value = NULL;
250 value_copy = NULL;
252 pthread_mutex_lock (&h->lock);
254 /* TODO: Checking this every time may be a bit much..? */
255 fbh_check_file (h);
257 status = c_avl_get (h->tree, key, (void *) &value);
258 if (status == 0)
259 {
260 assert (value != NULL);
261 value_copy = strdup (value);
262 }
264 pthread_mutex_unlock (&h->lock);
266 return (value_copy);
267 } /* }}} char *fbh_get */
269 /* vim: set sw=2 sts=2 et fdm=marker : */