diff options
Diffstat (limited to 'src/shared/dbus-loop.c')
| -rw-r--r-- | src/shared/dbus-loop.c | 263 |
1 files changed, 263 insertions, 0 deletions
diff --git a/src/shared/dbus-loop.c b/src/shared/dbus-loop.c new file mode 100644 index 0000000000..da0a00443a --- /dev/null +++ b/src/shared/dbus-loop.c @@ -0,0 +1,263 @@ +/*-*- 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 *e; + 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) { + free(e); + 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) { + free(e); + return FALSE; + } + + if (epoll_ctl(PTR_TO_INT(data), EPOLL_CTL_ADD, e->fd, &ev) < 0) { + close_nointr_nofail(e->fd); + free(e); + return FALSE; + } + + e->fd_is_dupped = true; + } + + dbus_watch_set_data(watch, e, NULL); + + return TRUE; +} + +static void remove_watch(DBusWatch *watch, void *data) { + EpollData *e; + + 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); + + free(e); +} + +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 *e; + + 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); + free(e); +} + +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; +} |