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/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2011 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <stdbool.h>
#include <assert.h>
#include <sys/epoll.h>
#include <string.h>
#include <errno.h>
#include <sys/timerfd.h>
#include <unistd.h>
#include "dbus-loop.h"
#include "dbus-common.h"
#include "util.h"
/* Minimal implementation of the dbus loop which integrates all dbus
* events into a single epoll fd which we can triviall integrate with
* other loops. Note that this is not used in the main systemd daemon
* since we run a more elaborate mainloop there. */
typedef struct EpollData {
int fd;
void *object;
bool is_timeout:1;
bool fd_is_dupped:1;
} EpollData;
static dbus_bool_t add_watch(DBusWatch *watch, void *data) {
EpollData _cleanup_free_ *e = NULL;
struct epoll_event ev;
assert(watch);
e = new0(EpollData, 1);
if (!e)
return FALSE;
e->fd = dbus_watch_get_unix_fd(watch);
e->object = watch;
e->is_timeout = false;
zero(ev);
ev.events = bus_flags_to_events(watch);
ev.data.ptr = e;
if (epoll_ctl(PTR_TO_INT(data), EPOLL_CTL_ADD, e->fd, &ev) < 0) {
if (errno != EEXIST)
return FALSE;
/* Hmm, bloody D-Bus creates multiple watches on the
* same fd. epoll() does not like that. As a dirty
* hack we simply dup() the fd and hence get a second
* one we can safely add to the epoll(). */
e->fd = dup(e->fd);
if (e->fd < 0)
return FALSE;
if (epoll_ctl(PTR_TO_INT(data), EPOLL_CTL_ADD, e->fd, &ev) < 0) {
close_nointr_nofail(e->fd);
return FALSE;
}
e->fd_is_dupped = true;
}
dbus_watch_set_data(watch, e, NULL);
e = NULL; /* prevent freeing */
return TRUE;
}
static void remove_watch(DBusWatch *watch, void *data) {
EpollData _cleanup_free_ *e = NULL;
assert(watch);
e = dbus_watch_get_data(watch);
if (!e)
return;
assert_se(epoll_ctl(PTR_TO_INT(data), EPOLL_CTL_DEL, e->fd, NULL) >= 0);
if (e->fd_is_dupped)
close_nointr_nofail(e->fd);
}
static void toggle_watch(DBusWatch *watch, void *data) {
EpollData *e;
struct epoll_event ev;
assert(watch);
e = dbus_watch_get_data(watch);
if (!e)
return;
zero(ev);
ev.events = bus_flags_to_events(watch);
ev.data.ptr = e;
assert_se(epoll_ctl(PTR_TO_INT(data), EPOLL_CTL_MOD, e->fd, &ev) == 0);
}
static int timeout_arm(EpollData *e) {
struct itimerspec its;
assert(e);
assert(e->is_timeout);
zero(its);
if (dbus_timeout_get_enabled(e->object)) {
timespec_store(&its.it_value, dbus_timeout_get_interval(e->object) * USEC_PER_MSEC);
its.it_interval = its.it_value;
}
if (timerfd_settime(e->fd, 0, &its, NULL) < 0)
return -errno;
return 0;
}
static dbus_bool_t add_timeout(DBusTimeout *timeout, void *data) {
EpollData *e;
struct epoll_event ev;
assert(timeout);
e = new0(EpollData, 1);
if (!e)
return FALSE;
e->fd = timerfd_create(CLOCK_MONOTONIC, TFD_NONBLOCK|TFD_CLOEXEC);
if (e->fd < 0)
goto fail;
e->object = timeout;
e->is_timeout = true;
if (timeout_arm(e) < 0)
goto fail;
zero(ev);
ev.events = EPOLLIN;
ev.data.ptr = e;
if (epoll_ctl(PTR_TO_INT(data), EPOLL_CTL_ADD, e->fd, &ev) < 0)
goto fail;
dbus_timeout_set_data(timeout, e, NULL);
return TRUE;
fail:
if (e->fd >= 0)
close_nointr_nofail(e->fd);
free(e);
return FALSE;
}
static void remove_timeout(DBusTimeout *timeout, void *data) {
EpollData _cleanup_free_ *e = NULL;
assert(timeout);
e = dbus_timeout_get_data(timeout);
if (!e)
return;
assert_se(epoll_ctl(PTR_TO_INT(data), EPOLL_CTL_DEL, e->fd, NULL) >= 0);
close_nointr_nofail(e->fd);
}
static void toggle_timeout(DBusTimeout *timeout, void *data) {
EpollData *e;
int r;
assert(timeout);
e = dbus_timeout_get_data(timeout);
if (!e)
return;
r = timeout_arm(e);
if (r < 0)
log_error("Failed to rearm timer: %s", strerror(-r));
}
int bus_loop_open(DBusConnection *c) {
int fd;
assert(c);
fd = epoll_create1(EPOLL_CLOEXEC);
if (fd < 0)
return -errno;
if (!dbus_connection_set_watch_functions(c, add_watch, remove_watch, toggle_watch, INT_TO_PTR(fd), NULL) ||
!dbus_connection_set_timeout_functions(c, add_timeout, remove_timeout, toggle_timeout, INT_TO_PTR(fd), NULL)) {
close_nointr_nofail(fd);
return -ENOMEM;
}
return fd;
}
int bus_loop_dispatch(int fd) {
int n;
struct epoll_event event;
EpollData *d;
assert(fd >= 0);
zero(event);
n = epoll_wait(fd, &event, 1, 0);
if (n < 0)
return errno == EAGAIN || errno == EINTR ? 0 : -errno;
assert_se(d = event.data.ptr);
if (d->is_timeout) {
DBusTimeout *t = d->object;
if (dbus_timeout_get_enabled(t))
dbus_timeout_handle(t);
} else {
DBusWatch *w = d->object;
if (dbus_watch_get_enabled(w))
dbus_watch_handle(w, bus_events_to_flags(event.events));
}
return 0;
}
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