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20263082 LP |
1 | /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ |
2 | ||
3 | /*** | |
4 | This file is part of systemd. | |
5 | ||
6 | Copyright 2011 Lennart Poettering | |
7 | ||
8 | systemd is free software; you can redistribute it and/or modify it | |
5430f7f2 LP |
9 | under the terms of the GNU Lesser General Public License as published by |
10 | the Free Software Foundation; either version 2.1 of the License, or | |
20263082 LP |
11 | (at your option) any later version. |
12 | ||
13 | systemd is distributed in the hope that it will be useful, but | |
14 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
5430f7f2 | 16 | Lesser General Public License for more details. |
20263082 | 17 | |
5430f7f2 | 18 | You should have received a copy of the GNU Lesser General Public License |
20263082 LP |
19 | along with systemd; If not, see <http://www.gnu.org/licenses/>. |
20 | ***/ | |
21 | ||
22 | #include <stdbool.h> | |
23 | #include <assert.h> | |
24 | #include <sys/epoll.h> | |
25 | #include <string.h> | |
26 | #include <errno.h> | |
27 | #include <sys/timerfd.h> | |
28 | #include <unistd.h> | |
29 | ||
30 | #include "dbus-loop.h" | |
31 | #include "dbus-common.h" | |
32 | #include "util.h" | |
33 | ||
34 | /* Minimal implementation of the dbus loop which integrates all dbus | |
35 | * events into a single epoll fd which we can triviall integrate with | |
36 | * other loops. Note that this is not used in the main systemd daemon | |
37 | * since we run a more elaborate mainloop there. */ | |
38 | ||
39 | typedef struct EpollData { | |
40 | int fd; | |
41 | void *object; | |
42 | bool is_timeout:1; | |
43 | bool fd_is_dupped:1; | |
44 | } EpollData; | |
45 | ||
46 | static dbus_bool_t add_watch(DBusWatch *watch, void *data) { | |
7fd1b19b | 47 | _cleanup_free_ EpollData *e = NULL; |
2f9f5aa0 | 48 | struct epoll_event ev = {}; |
20263082 LP |
49 | |
50 | assert(watch); | |
51 | ||
52 | e = new0(EpollData, 1); | |
53 | if (!e) | |
54 | return FALSE; | |
55 | ||
56 | e->fd = dbus_watch_get_unix_fd(watch); | |
57 | e->object = watch; | |
58 | e->is_timeout = false; | |
59 | ||
20263082 | 60 | ev.events = bus_flags_to_events(watch); |
2f9f5aa0 | 61 | ev.data.ptr = e; |
20263082 LP |
62 | |
63 | if (epoll_ctl(PTR_TO_INT(data), EPOLL_CTL_ADD, e->fd, &ev) < 0) { | |
64 | ||
e62d8c39 | 65 | if (errno != EEXIST) |
20263082 | 66 | return FALSE; |
20263082 LP |
67 | |
68 | /* Hmm, bloody D-Bus creates multiple watches on the | |
69 | * same fd. epoll() does not like that. As a dirty | |
70 | * hack we simply dup() the fd and hence get a second | |
71 | * one we can safely add to the epoll(). */ | |
72 | ||
73 | e->fd = dup(e->fd); | |
e62d8c39 | 74 | if (e->fd < 0) |
20263082 | 75 | return FALSE; |
20263082 LP |
76 | |
77 | if (epoll_ctl(PTR_TO_INT(data), EPOLL_CTL_ADD, e->fd, &ev) < 0) { | |
78 | close_nointr_nofail(e->fd); | |
20263082 LP |
79 | return FALSE; |
80 | } | |
81 | ||
82 | e->fd_is_dupped = true; | |
83 | } | |
84 | ||
85 | dbus_watch_set_data(watch, e, NULL); | |
e62d8c39 | 86 | e = NULL; /* prevent freeing */ |
20263082 LP |
87 | |
88 | return TRUE; | |
89 | } | |
90 | ||
91 | static void remove_watch(DBusWatch *watch, void *data) { | |
7fd1b19b | 92 | _cleanup_free_ EpollData *e = NULL; |
20263082 LP |
93 | |
94 | assert(watch); | |
95 | ||
96 | e = dbus_watch_get_data(watch); | |
97 | if (!e) | |
98 | return; | |
99 | ||
100 | assert_se(epoll_ctl(PTR_TO_INT(data), EPOLL_CTL_DEL, e->fd, NULL) >= 0); | |
101 | ||
102 | if (e->fd_is_dupped) | |
103 | close_nointr_nofail(e->fd); | |
20263082 LP |
104 | } |
105 | ||
106 | static void toggle_watch(DBusWatch *watch, void *data) { | |
107 | EpollData *e; | |
b92bea5d | 108 | struct epoll_event ev = {}; |
20263082 LP |
109 | |
110 | assert(watch); | |
111 | ||
112 | e = dbus_watch_get_data(watch); | |
113 | if (!e) | |
114 | return; | |
115 | ||
20263082 | 116 | ev.data.ptr = e; |
b92bea5d | 117 | ev.events = bus_flags_to_events(watch); |
20263082 LP |
118 | |
119 | assert_se(epoll_ctl(PTR_TO_INT(data), EPOLL_CTL_MOD, e->fd, &ev) == 0); | |
120 | } | |
121 | ||
122 | static int timeout_arm(EpollData *e) { | |
b92bea5d | 123 | struct itimerspec its = {}; |
20263082 LP |
124 | |
125 | assert(e); | |
126 | assert(e->is_timeout); | |
127 | ||
20263082 LP |
128 | if (dbus_timeout_get_enabled(e->object)) { |
129 | timespec_store(&its.it_value, dbus_timeout_get_interval(e->object) * USEC_PER_MSEC); | |
130 | its.it_interval = its.it_value; | |
131 | } | |
132 | ||
133 | if (timerfd_settime(e->fd, 0, &its, NULL) < 0) | |
134 | return -errno; | |
135 | ||
136 | return 0; | |
137 | } | |
138 | ||
139 | static dbus_bool_t add_timeout(DBusTimeout *timeout, void *data) { | |
140 | EpollData *e; | |
b92bea5d | 141 | struct epoll_event ev = {}; |
20263082 LP |
142 | |
143 | assert(timeout); | |
144 | ||
145 | e = new0(EpollData, 1); | |
146 | if (!e) | |
147 | return FALSE; | |
148 | ||
149 | e->fd = timerfd_create(CLOCK_MONOTONIC, TFD_NONBLOCK|TFD_CLOEXEC); | |
150 | if (e->fd < 0) | |
151 | goto fail; | |
152 | ||
153 | e->object = timeout; | |
154 | e->is_timeout = true; | |
155 | ||
156 | if (timeout_arm(e) < 0) | |
157 | goto fail; | |
158 | ||
20263082 LP |
159 | ev.events = EPOLLIN; |
160 | ev.data.ptr = e; | |
161 | ||
162 | if (epoll_ctl(PTR_TO_INT(data), EPOLL_CTL_ADD, e->fd, &ev) < 0) | |
163 | goto fail; | |
164 | ||
165 | dbus_timeout_set_data(timeout, e, NULL); | |
166 | ||
167 | return TRUE; | |
168 | ||
169 | fail: | |
170 | if (e->fd >= 0) | |
171 | close_nointr_nofail(e->fd); | |
172 | ||
173 | free(e); | |
174 | return FALSE; | |
175 | } | |
176 | ||
177 | static void remove_timeout(DBusTimeout *timeout, void *data) { | |
7fd1b19b | 178 | _cleanup_free_ EpollData *e = NULL; |
20263082 LP |
179 | |
180 | assert(timeout); | |
181 | ||
182 | e = dbus_timeout_get_data(timeout); | |
183 | if (!e) | |
184 | return; | |
185 | ||
186 | assert_se(epoll_ctl(PTR_TO_INT(data), EPOLL_CTL_DEL, e->fd, NULL) >= 0); | |
187 | close_nointr_nofail(e->fd); | |
20263082 LP |
188 | } |
189 | ||
190 | static void toggle_timeout(DBusTimeout *timeout, void *data) { | |
191 | EpollData *e; | |
192 | int r; | |
193 | ||
194 | assert(timeout); | |
195 | ||
196 | e = dbus_timeout_get_data(timeout); | |
197 | if (!e) | |
198 | return; | |
199 | ||
200 | r = timeout_arm(e); | |
201 | if (r < 0) | |
202 | log_error("Failed to rearm timer: %s", strerror(-r)); | |
203 | } | |
204 | ||
205 | int bus_loop_open(DBusConnection *c) { | |
206 | int fd; | |
207 | ||
208 | assert(c); | |
209 | ||
210 | fd = epoll_create1(EPOLL_CLOEXEC); | |
211 | if (fd < 0) | |
212 | return -errno; | |
213 | ||
214 | if (!dbus_connection_set_watch_functions(c, add_watch, remove_watch, toggle_watch, INT_TO_PTR(fd), NULL) || | |
215 | !dbus_connection_set_timeout_functions(c, add_timeout, remove_timeout, toggle_timeout, INT_TO_PTR(fd), NULL)) { | |
216 | close_nointr_nofail(fd); | |
217 | return -ENOMEM; | |
218 | } | |
219 | ||
220 | return fd; | |
221 | } | |
222 | ||
223 | int bus_loop_dispatch(int fd) { | |
224 | int n; | |
b92bea5d | 225 | struct epoll_event event = {}; |
20263082 LP |
226 | EpollData *d; |
227 | ||
228 | assert(fd >= 0); | |
229 | ||
20263082 LP |
230 | n = epoll_wait(fd, &event, 1, 0); |
231 | if (n < 0) | |
232 | return errno == EAGAIN || errno == EINTR ? 0 : -errno; | |
233 | ||
234 | assert_se(d = event.data.ptr); | |
235 | ||
236 | if (d->is_timeout) { | |
237 | DBusTimeout *t = d->object; | |
238 | ||
239 | if (dbus_timeout_get_enabled(t)) | |
240 | dbus_timeout_handle(t); | |
241 | } else { | |
242 | DBusWatch *w = d->object; | |
243 | ||
244 | if (dbus_watch_get_enabled(w)) | |
245 | dbus_watch_handle(w, bus_events_to_flags(event.events)); | |
246 | } | |
247 | ||
248 | return 0; | |
249 | } |