1 /* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
2 /* dbus-resources.c Resource tracking/limits
3 *
4 * Copyright (C) 2003 Red Hat Inc.
5 *
6 * Licensed under the Academic Free License version 2.1
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 *
22 */
23
24 #include <config.h>
25 #include <dbus/dbus-resources.h>
26 #include <dbus/dbus-internals.h>
27
28 /**
29 * @defgroup DBusResources Resource limits related code
30 * @ingroup DBusInternals
31 * @brief DBusCounter and other stuff related to resource limits
32 *
33 * Types and functions related to tracking resource limits,
34 * such as the maximum amount of memory/unix fds a connection can use
35 * for messages, etc.
36 */
37
38 /**
39 * @defgroup DBusResourcesInternals Resource limits implementation details
40 * @ingroup DBusInternals
41 * @brief Resource limits implementation details
42 *
43 * Implementation details of resource limits code.
44 *
45 * @{
46 */
47
48 /**
49 * @brief Internals of DBusCounter.
50 *
51 * DBusCounter internals. DBusCounter is an opaque object, it must be
52 * used via accessor functions.
53 */
54 struct DBusCounter
55 {
56 int refcount; /**< reference count */
57
58 long size_value; /**< current size counter value */
59 long unix_fd_value; /**< current unix fd counter value */
60
61 long notify_size_guard_value; /**< call notify function when crossing this size value */
62 long notify_unix_fd_guard_value; /**< call notify function when crossing this unix fd value */
63
64 DBusCounterNotifyFunction notify_function; /**< notify function */
65 void *notify_data; /**< data for notify function */
66 };
67
68 /** @} */ /* end of resource limits internals docs */
69
70 /**
71 * @addtogroup DBusResources
72 * @{
73 */
74
75 /**
76 * Creates a new DBusCounter. DBusCounter is used
77 * to count usage of some resource such as memory.
78 *
79 * @returns new counter or #NULL on failure
80 */
81 DBusCounter*
_dbus_counter_new(void)82 _dbus_counter_new (void)
83 {
84 DBusCounter *counter;
85
86 counter = dbus_new (DBusCounter, 1);
87 if (counter == NULL)
88 return NULL;
89
90 counter->refcount = 1;
91 counter->size_value = 0;
92 counter->unix_fd_value = 0;
93
94 counter->notify_size_guard_value = 0;
95 counter->notify_unix_fd_guard_value = 0;
96 counter->notify_function = NULL;
97 counter->notify_data = NULL;
98
99 return counter;
100 }
101
102 /**
103 * Increments refcount of the counter
104 *
105 * @param counter the counter
106 * @returns the counter
107 */
108 DBusCounter *
_dbus_counter_ref(DBusCounter * counter)109 _dbus_counter_ref (DBusCounter *counter)
110 {
111 _dbus_assert (counter->refcount > 0);
112
113 counter->refcount += 1;
114
115 return counter;
116 }
117
118 /**
119 * Decrements refcount of the counter and possibly
120 * finalizes the counter.
121 *
122 * @param counter the counter
123 */
124 void
_dbus_counter_unref(DBusCounter * counter)125 _dbus_counter_unref (DBusCounter *counter)
126 {
127 _dbus_assert (counter->refcount > 0);
128
129 counter->refcount -= 1;
130
131 if (counter->refcount == 0)
132 {
133
134 dbus_free (counter);
135 }
136 }
137
138 /**
139 * Adjusts the value of the size counter by the given
140 * delta which may be positive or negative.
141 * Calls the notify function from _dbus_counter_set_notify()
142 * if that function has been specified.
143 *
144 * @param counter the counter
145 * @param delta value to add to the size counter's current value
146 */
147 void
_dbus_counter_adjust_size(DBusCounter * counter,long delta)148 _dbus_counter_adjust_size (DBusCounter *counter,
149 long delta)
150 {
151 long old = counter->size_value;
152
153 counter->size_value += delta;
154
155 #if 0
156 _dbus_verbose ("Adjusting counter %ld by %ld = %ld\n",
157 old, delta, counter->size_value);
158 #endif
159
160 if (counter->notify_function != NULL &&
161 ((old < counter->notify_size_guard_value &&
162 counter->size_value >= counter->notify_size_guard_value) ||
163 (old >= counter->notify_size_guard_value &&
164 counter->size_value < counter->notify_size_guard_value)))
165 (* counter->notify_function) (counter, counter->notify_data);
166 }
167
168 /**
169 * Adjusts the value of the unix fd counter by the given
170 * delta which may be positive or negative.
171 * Calls the notify function from _dbus_counter_set_notify()
172 * if that function has been specified.
173 *
174 * @param counter the counter
175 * @param delta value to add to the unix fds counter's current value
176 */
177 void
_dbus_counter_adjust_unix_fd(DBusCounter * counter,long delta)178 _dbus_counter_adjust_unix_fd (DBusCounter *counter,
179 long delta)
180 {
181 long old = counter->unix_fd_value;
182
183 counter->unix_fd_value += delta;
184
185 #if 0
186 _dbus_verbose ("Adjusting counter %ld by %ld = %ld\n",
187 old, delta, counter->unix_fd_value);
188 #endif
189
190 if (counter->notify_function != NULL &&
191 ((old < counter->notify_unix_fd_guard_value &&
192 counter->unix_fd_value >= counter->notify_unix_fd_guard_value) ||
193 (old >= counter->notify_unix_fd_guard_value &&
194 counter->unix_fd_value < counter->notify_unix_fd_guard_value)))
195 (* counter->notify_function) (counter, counter->notify_data);
196 }
197
198 /**
199 * Gets the current value of the size counter.
200 *
201 * @param counter the counter
202 * @returns its current size value
203 */
204 long
_dbus_counter_get_size_value(DBusCounter * counter)205 _dbus_counter_get_size_value (DBusCounter *counter)
206 {
207 return counter->size_value;
208 }
209
210 /**
211 * Gets the current value of the unix fd counter.
212 *
213 * @param counter the counter
214 * @returns its current unix fd value
215 */
216 long
_dbus_counter_get_unix_fd_value(DBusCounter * counter)217 _dbus_counter_get_unix_fd_value (DBusCounter *counter)
218 {
219 return counter->unix_fd_value;
220 }
221
222 /**
223 * Sets the notify function for this counter; the notify function is
224 * called whenever the counter's values cross the guard values in
225 * either direction (moving up, or moving down).
226 *
227 * @param counter the counter
228 * @param size_guard_value the value we're notified if the size counter crosses
229 * @param unix_fd_guard_value the value we're notified if the unix fd counter crosses
230 * @param function function to call in order to notify
231 * @param user_data data to pass to the function
232 */
233 void
_dbus_counter_set_notify(DBusCounter * counter,long size_guard_value,long unix_fd_guard_value,DBusCounterNotifyFunction function,void * user_data)234 _dbus_counter_set_notify (DBusCounter *counter,
235 long size_guard_value,
236 long unix_fd_guard_value,
237 DBusCounterNotifyFunction function,
238 void *user_data)
239 {
240 counter->notify_size_guard_value = size_guard_value;
241 counter->notify_unix_fd_guard_value = unix_fd_guard_value;
242 counter->notify_function = function;
243 counter->notify_data = user_data;
244 }
245
246 /** @} */ /* end of resource limits exported API */
247