summaryrefslogtreecommitdiff
path: root/src/libsystemd/sd-event/sd-event.c
diff options
context:
space:
mode:
Diffstat (limited to 'src/libsystemd/sd-event/sd-event.c')
-rw-r--r--src/libsystemd/sd-event/sd-event.c430
1 files changed, 292 insertions, 138 deletions
diff --git a/src/libsystemd/sd-event/sd-event.c b/src/libsystemd/sd-event/sd-event.c
index c419be820a..838ee4d454 100644
--- a/src/libsystemd/sd-event/sd-event.c
+++ b/src/libsystemd/sd-event/sd-event.c
@@ -56,9 +56,22 @@ typedef enum EventSourceType {
_SOURCE_EVENT_SOURCE_TYPE_INVALID = -1
} EventSourceType;
+/* All objects we use in epoll events start with this value, so that
+ * we know how to dispatch it */
+typedef enum WakeupType {
+ WAKEUP_NONE,
+ WAKEUP_EVENT_SOURCE,
+ WAKEUP_CLOCK_DATA,
+ WAKEUP_SIGNAL_DATA,
+ _WAKEUP_TYPE_MAX,
+ _WAKEUP_TYPE_INVALID = -1,
+} WakeupType;
+
#define EVENT_SOURCE_IS_TIME(t) IN_SET((t), SOURCE_TIME_REALTIME, SOURCE_TIME_BOOTTIME, SOURCE_TIME_MONOTONIC, SOURCE_TIME_REALTIME_ALARM, SOURCE_TIME_BOOTTIME_ALARM)
struct sd_event_source {
+ WakeupType wakeup;
+
unsigned n_ref;
sd_event *event;
@@ -120,6 +133,7 @@ struct sd_event_source {
};
struct clock_data {
+ WakeupType wakeup;
int fd;
/* For all clocks we maintain two priority queues each, one
@@ -136,11 +150,23 @@ struct clock_data {
bool needs_rearm:1;
};
+struct signal_data {
+ WakeupType wakeup;
+
+ /* For each priority we maintain one signal fd, so that we
+ * only have to dequeue a single event per priority at a
+ * time. */
+
+ int fd;
+ int64_t priority;
+ sigset_t sigset;
+ sd_event_source *current;
+};
+
struct sd_event {
unsigned n_ref;
int epoll_fd;
- int signal_fd;
int watchdog_fd;
Prioq *pending;
@@ -157,8 +183,8 @@ struct sd_event {
usec_t perturb;
- sigset_t sigset;
- sd_event_source **signal_sources;
+ sd_event_source **signal_sources; /* indexed by signal number */
+ Hashmap *signal_data; /* indexed by priority */
Hashmap *child_sources;
unsigned n_enabled_child_sources;
@@ -355,6 +381,7 @@ static int exit_prioq_compare(const void *a, const void *b) {
static void free_clock_data(struct clock_data *d) {
assert(d);
+ assert(d->wakeup == WAKEUP_CLOCK_DATA);
safe_close(d->fd);
prioq_free(d->earliest);
@@ -378,7 +405,6 @@ static void event_free(sd_event *e) {
*(e->default_event_ptr) = NULL;
safe_close(e->epoll_fd);
- safe_close(e->signal_fd);
safe_close(e->watchdog_fd);
free_clock_data(&e->realtime);
@@ -392,6 +418,7 @@ static void event_free(sd_event *e) {
prioq_free(e->exit);
free(e->signal_sources);
+ hashmap_free(e->signal_data);
hashmap_free(e->child_sources);
set_free(e->post_sources);
@@ -409,13 +436,12 @@ _public_ int sd_event_new(sd_event** ret) {
return -ENOMEM;
e->n_ref = 1;
- e->signal_fd = e->watchdog_fd = e->epoll_fd = e->realtime.fd = e->boottime.fd = e->monotonic.fd = e->realtime_alarm.fd = e->boottime_alarm.fd = -1;
+ e->watchdog_fd = e->epoll_fd = e->realtime.fd = e->boottime.fd = e->monotonic.fd = e->realtime_alarm.fd = e->boottime_alarm.fd = -1;
e->realtime.next = e->boottime.next = e->monotonic.next = e->realtime_alarm.next = e->boottime_alarm.next = USEC_INFINITY;
+ e->realtime.wakeup = e->boottime.wakeup = e->monotonic.wakeup = e->realtime_alarm.wakeup = e->boottime_alarm.wakeup = WAKEUP_CLOCK_DATA;
e->original_pid = getpid();
e->perturb = USEC_INFINITY;
- assert_se(sigemptyset(&e->sigset) == 0);
-
e->pending = prioq_new(pending_prioq_compare);
if (!e->pending) {
r = -ENOMEM;
@@ -509,7 +535,6 @@ static int source_io_register(
r = epoll_ctl(s->event->epoll_fd, EPOLL_CTL_MOD, s->io.fd, &ev);
else
r = epoll_ctl(s->event->epoll_fd, EPOLL_CTL_ADD, s->io.fd, &ev);
-
if (r < 0)
return -errno;
@@ -591,45 +616,171 @@ static struct clock_data* event_get_clock_data(sd_event *e, EventSourceType t) {
}
}
-static bool need_signal(sd_event *e, int signal) {
- return (e->signal_sources && e->signal_sources[signal] &&
- e->signal_sources[signal]->enabled != SD_EVENT_OFF)
- ||
- (signal == SIGCHLD &&
- e->n_enabled_child_sources > 0);
-}
+static int event_make_signal_data(
+ sd_event *e,
+ int sig,
+ struct signal_data **ret) {
-static int event_update_signal_fd(sd_event *e) {
struct epoll_event ev = {};
- bool add_to_epoll;
+ struct signal_data *d;
+ bool added = false;
+ sigset_t ss_copy;
+ int64_t priority;
int r;
assert(e);
if (event_pid_changed(e))
- return 0;
+ return -ECHILD;
- add_to_epoll = e->signal_fd < 0;
+ if (e->signal_sources && e->signal_sources[sig])
+ priority = e->signal_sources[sig]->priority;
+ else
+ priority = 0;
- r = signalfd(e->signal_fd, &e->sigset, SFD_NONBLOCK|SFD_CLOEXEC);
- if (r < 0)
- return -errno;
+ d = hashmap_get(e->signal_data, &priority);
+ if (d) {
+ if (sigismember(&d->sigset, sig) > 0) {
+ if (ret)
+ *ret = d;
+ return 0;
+ }
+ } else {
+ r = hashmap_ensure_allocated(&e->signal_data, &uint64_hash_ops);
+ if (r < 0)
+ return r;
+
+ d = new0(struct signal_data, 1);
+ if (!d)
+ return -ENOMEM;
+
+ d->wakeup = WAKEUP_SIGNAL_DATA;
+ d->fd = -1;
+ d->priority = priority;
+
+ r = hashmap_put(e->signal_data, &d->priority, d);
+ if (r < 0)
+ return r;
- e->signal_fd = r;
+ added = true;
+ }
+
+ ss_copy = d->sigset;
+ assert_se(sigaddset(&ss_copy, sig) >= 0);
+
+ r = signalfd(d->fd, &ss_copy, SFD_NONBLOCK|SFD_CLOEXEC);
+ if (r < 0) {
+ r = -errno;
+ goto fail;
+ }
+
+ d->sigset = ss_copy;
- if (!add_to_epoll)
+ if (d->fd >= 0) {
+ if (ret)
+ *ret = d;
return 0;
+ }
+
+ d->fd = r;
ev.events = EPOLLIN;
- ev.data.ptr = INT_TO_PTR(SOURCE_SIGNAL);
+ ev.data.ptr = d;
- r = epoll_ctl(e->epoll_fd, EPOLL_CTL_ADD, e->signal_fd, &ev);
- if (r < 0) {
- e->signal_fd = safe_close(e->signal_fd);
- return -errno;
+ r = epoll_ctl(e->epoll_fd, EPOLL_CTL_ADD, d->fd, &ev);
+ if (r < 0) {
+ r = -errno;
+ goto fail;
}
+ if (ret)
+ *ret = d;
+
return 0;
+
+fail:
+ if (added) {
+ d->fd = safe_close(d->fd);
+ hashmap_remove(e->signal_data, &d->priority);
+ free(d);
+ }
+
+ return r;
+}
+
+static void event_unmask_signal_data(sd_event *e, struct signal_data *d, int sig) {
+ assert(e);
+ assert(d);
+
+ /* Turns off the specified signal in the signal data
+ * object. If the signal mask of the object becomes empty that
+ * way removes it. */
+
+ if (sigismember(&d->sigset, sig) == 0)
+ return;
+
+ assert_se(sigdelset(&d->sigset, sig) >= 0);
+
+ if (sigisemptyset(&d->sigset)) {
+
+ /* If all the mask is all-zero we can get rid of the structure */
+ hashmap_remove(e->signal_data, &d->priority);
+ assert(!d->current);
+ safe_close(d->fd);
+ free(d);
+ return;
+ }
+
+ assert(d->fd >= 0);
+
+ if (signalfd(d->fd, &d->sigset, SFD_NONBLOCK|SFD_CLOEXEC) < 0)
+ log_debug_errno(errno, "Failed to unset signal bit, ignoring: %m");
+}
+
+static void event_gc_signal_data(sd_event *e, const int64_t *priority, int sig) {
+ struct signal_data *d;
+ static const int64_t zero_priority = 0;
+
+ assert(e);
+
+ /* Rechecks if the specified signal is still something we are
+ * interested in. If not, we'll unmask it, and possibly drop
+ * the signalfd for it. */
+
+ if (sig == SIGCHLD &&
+ e->n_enabled_child_sources > 0)
+ return;
+
+ if (e->signal_sources &&
+ e->signal_sources[sig] &&
+ e->signal_sources[sig]->enabled != SD_EVENT_OFF)
+ return;
+
+ /*
+ * The specified signal might be enabled in three different queues:
+ *
+ * 1) the one that belongs to the priority passed (if it is non-NULL)
+ * 2) the one that belongs to the priority of the event source of the signal (if there is one)
+ * 3) the 0 priority (to cover the SIGCHLD case)
+ *
+ * Hence, let's remove it from all three here.
+ */
+
+ if (priority) {
+ d = hashmap_get(e->signal_data, priority);
+ if (d)
+ event_unmask_signal_data(e, d, sig);
+ }
+
+ if (e->signal_sources && e->signal_sources[sig]) {
+ d = hashmap_get(e->signal_data, &e->signal_sources[sig]->priority);
+ if (d)
+ event_unmask_signal_data(e, d, sig);
+ }
+
+ d = hashmap_get(e->signal_data, &zero_priority);
+ if (d)
+ event_unmask_signal_data(e, d, sig);
}
static void source_disconnect(sd_event_source *s) {
@@ -668,17 +819,11 @@ static void source_disconnect(sd_event_source *s) {
case SOURCE_SIGNAL:
if (s->signal.sig > 0) {
+
if (s->event->signal_sources)
s->event->signal_sources[s->signal.sig] = NULL;
- /* If the signal was on and now it is off... */
- if (s->enabled != SD_EVENT_OFF && !need_signal(s->event, s->signal.sig)) {
- assert_se(sigdelset(&s->event->sigset, s->signal.sig) == 0);
-
- (void) event_update_signal_fd(s->event);
- /* If disabling failed, we might get a spurious event,
- * but otherwise nothing bad should happen. */
- }
+ event_gc_signal_data(s->event, &s->priority, s->signal.sig);
}
break;
@@ -688,18 +833,10 @@ static void source_disconnect(sd_event_source *s) {
if (s->enabled != SD_EVENT_OFF) {
assert(s->event->n_enabled_child_sources > 0);
s->event->n_enabled_child_sources--;
-
- /* We know the signal was on, if it is off now... */
- if (!need_signal(s->event, SIGCHLD)) {
- assert_se(sigdelset(&s->event->sigset, SIGCHLD) == 0);
-
- (void) event_update_signal_fd(s->event);
- /* If disabling failed, we might get a spurious event,
- * but otherwise nothing bad should happen. */
- }
}
- hashmap_remove(s->event->child_sources, INT_TO_PTR(s->child.pid));
+ (void) hashmap_remove(s->event->child_sources, INT_TO_PTR(s->child.pid));
+ event_gc_signal_data(s->event, &s->priority, SIGCHLD);
}
break;
@@ -778,6 +915,14 @@ static int source_set_pending(sd_event_source *s, bool b) {
d->needs_rearm = true;
}
+ if (s->type == SOURCE_SIGNAL && !b) {
+ struct signal_data *d;
+
+ d = hashmap_get(s->event->signal_data, &s->priority);
+ if (d && d->current == s)
+ d->current = NULL;
+ }
+
return 0;
}
@@ -827,6 +972,7 @@ _public_ int sd_event_add_io(
if (!s)
return -ENOMEM;
+ s->wakeup = WAKEUP_EVENT_SOURCE;
s->io.fd = fd;
s->io.events = events;
s->io.callback = callback;
@@ -883,7 +1029,7 @@ static int event_setup_timer_fd(
return -errno;
ev.events = EPOLLIN;
- ev.data.ptr = INT_TO_PTR(clock_to_event_source_type(clock));
+ ev.data.ptr = d;
r = epoll_ctl(e->epoll_fd, EPOLL_CTL_ADD, fd, &ev);
if (r < 0) {
@@ -993,9 +1139,9 @@ _public_ int sd_event_add_signal(
void *userdata) {
sd_event_source *s;
+ struct signal_data *d;
sigset_t ss;
int r;
- bool previous;
assert_return(e, -EINVAL);
assert_return(sig > 0, -EINVAL);
@@ -1020,8 +1166,6 @@ _public_ int sd_event_add_signal(
} else if (e->signal_sources[sig])
return -EBUSY;
- previous = need_signal(e, sig);
-
s = source_new(e, !ret, SOURCE_SIGNAL);
if (!s)
return -ENOMEM;
@@ -1033,14 +1177,10 @@ _public_ int sd_event_add_signal(
e->signal_sources[sig] = s;
- if (!previous) {
- assert_se(sigaddset(&e->sigset, sig) == 0);
-
- r = event_update_signal_fd(e);
- if (r < 0) {
- source_free(s);
- return r;
- }
+ r = event_make_signal_data(e, sig, &d);
+ if (r < 0) {
+ source_free(s);
+ return r;
}
/* Use the signal name as description for the event source by default */
@@ -1062,7 +1202,6 @@ _public_ int sd_event_add_child(
sd_event_source *s;
int r;
- bool previous;
assert_return(e, -EINVAL);
assert_return(pid > 1, -EINVAL);
@@ -1079,8 +1218,6 @@ _public_ int sd_event_add_child(
if (hashmap_contains(e->child_sources, INT_TO_PTR(pid)))
return -EBUSY;
- previous = need_signal(e, SIGCHLD);
-
s = source_new(e, !ret, SOURCE_CHILD);
if (!s)
return -ENOMEM;
@@ -1099,14 +1236,11 @@ _public_ int sd_event_add_child(
e->n_enabled_child_sources ++;
- if (!previous) {
- assert_se(sigaddset(&e->sigset, SIGCHLD) == 0);
-
- r = event_update_signal_fd(e);
- if (r < 0) {
- source_free(s);
- return r;
- }
+ r = event_make_signal_data(e, SIGCHLD, NULL);
+ if (r < 0) {
+ e->n_enabled_child_sources--;
+ source_free(s);
+ return r;
}
e->need_process_child = true;
@@ -1406,6 +1540,8 @@ _public_ int sd_event_source_get_priority(sd_event_source *s, int64_t *priority)
}
_public_ int sd_event_source_set_priority(sd_event_source *s, int64_t priority) {
+ int r;
+
assert_return(s, -EINVAL);
assert_return(s->event->state != SD_EVENT_FINISHED, -ESTALE);
assert_return(!event_pid_changed(s->event), -ECHILD);
@@ -1413,7 +1549,25 @@ _public_ int sd_event_source_set_priority(sd_event_source *s, int64_t priority)
if (s->priority == priority)
return 0;
- s->priority = priority;
+ if (s->type == SOURCE_SIGNAL && s->enabled != SD_EVENT_OFF) {
+ struct signal_data *old, *d;
+
+ /* Move us from the signalfd belonging to the old
+ * priority to the signalfd of the new priority */
+
+ assert_se(old = hashmap_get(s->event->signal_data, &s->priority));
+
+ s->priority = priority;
+
+ r = event_make_signal_data(s->event, s->signal.sig, &d);
+ if (r < 0) {
+ s->priority = old->priority;
+ return r;
+ }
+
+ event_unmask_signal_data(s->event, old, s->signal.sig);
+ } else
+ s->priority = priority;
if (s->pending)
prioq_reshuffle(s->event->pending, s, &s->pending_index);
@@ -1478,34 +1632,18 @@ _public_ int sd_event_source_set_enabled(sd_event_source *s, int m) {
}
case SOURCE_SIGNAL:
- assert(need_signal(s->event, s->signal.sig));
-
s->enabled = m;
- if (!need_signal(s->event, s->signal.sig)) {
- assert_se(sigdelset(&s->event->sigset, s->signal.sig) == 0);
-
- (void) event_update_signal_fd(s->event);
- /* If disabling failed, we might get a spurious event,
- * but otherwise nothing bad should happen. */
- }
-
+ event_gc_signal_data(s->event, &s->priority, s->signal.sig);
break;
case SOURCE_CHILD:
- assert(need_signal(s->event, SIGCHLD));
-
s->enabled = m;
assert(s->event->n_enabled_child_sources > 0);
s->event->n_enabled_child_sources--;
- if (!need_signal(s->event, SIGCHLD)) {
- assert_se(sigdelset(&s->event->sigset, SIGCHLD) == 0);
-
- (void) event_update_signal_fd(s->event);
- }
-
+ event_gc_signal_data(s->event, &s->priority, SIGCHLD);
break;
case SOURCE_EXIT:
@@ -1551,37 +1689,33 @@ _public_ int sd_event_source_set_enabled(sd_event_source *s, int m) {
}
case SOURCE_SIGNAL:
- /* Check status before enabling. */
- if (!need_signal(s->event, s->signal.sig)) {
- assert_se(sigaddset(&s->event->sigset, s->signal.sig) == 0);
-
- r = event_update_signal_fd(s->event);
- if (r < 0) {
- s->enabled = SD_EVENT_OFF;
- return r;
- }
- }
s->enabled = m;
+
+ r = event_make_signal_data(s->event, s->signal.sig, NULL);
+ if (r < 0) {
+ s->enabled = SD_EVENT_OFF;
+ event_gc_signal_data(s->event, &s->priority, s->signal.sig);
+ return r;
+ }
+
break;
case SOURCE_CHILD:
- /* Check status before enabling. */
- if (s->enabled == SD_EVENT_OFF) {
- if (!need_signal(s->event, SIGCHLD)) {
- assert_se(sigaddset(&s->event->sigset, s->signal.sig) == 0);
-
- r = event_update_signal_fd(s->event);
- if (r < 0) {
- s->enabled = SD_EVENT_OFF;
- return r;
- }
- }
+ if (s->enabled == SD_EVENT_OFF)
s->event->n_enabled_child_sources++;
- }
s->enabled = m;
+
+ r = event_make_signal_data(s->event, s->signal.sig, SIGCHLD);
+ if (r < 0) {
+ s->enabled = SD_EVENT_OFF;
+ s->event->n_enabled_child_sources--;
+ event_gc_signal_data(s->event, &s->priority, SIGCHLD);
+ return r;
+ }
+
break;
case SOURCE_EXIT:
@@ -2025,20 +2159,35 @@ static int process_child(sd_event *e) {
return 0;
}
-static int process_signal(sd_event *e, uint32_t events) {
+static int process_signal(sd_event *e, struct signal_data *d, uint32_t events) {
bool read_one = false;
int r;
assert(e);
-
assert_return(events == EPOLLIN, -EIO);
+ /* If there's a signal queued on this priority and SIGCHLD is
+ on this priority too, then make sure to recheck the
+ children we watch. This is because we only ever dequeue
+ the first signal per priority, and if we dequeue one, and
+ SIGCHLD might be enqueued later we wouldn't know, but we
+ might have higher priority children we care about hence we
+ need to check that explicitly. */
+
+ if (sigismember(&d->sigset, SIGCHLD))
+ e->need_process_child = true;
+
+ /* If there's already an event source pending for this
+ * priority we don't read another */
+ if (d->current)
+ return 0;
+
for (;;) {
struct signalfd_siginfo si;
ssize_t n;
sd_event_source *s = NULL;
- n = read(e->signal_fd, &si, sizeof(si));
+ n = read(d->fd, &si, sizeof(si));
if (n < 0) {
if (errno == EAGAIN || errno == EINTR)
return read_one;
@@ -2053,24 +2202,21 @@ static int process_signal(sd_event *e, uint32_t events) {
read_one = true;
- if (si.ssi_signo == SIGCHLD) {
- r = process_child(e);
- if (r < 0)
- return r;
- if (r > 0)
- continue;
- }
-
if (e->signal_sources)
s = e->signal_sources[si.ssi_signo];
-
if (!s)
continue;
+ if (s->pending)
+ continue;
s->signal.siginfo = si;
+ d->current = s;
+
r = source_set_pending(s, true);
if (r < 0)
return r;
+
+ return 1;
}
}
@@ -2388,23 +2534,31 @@ _public_ int sd_event_wait(sd_event *e, uint64_t timeout) {
for (i = 0; i < m; i++) {
- if (ev_queue[i].data.ptr == INT_TO_PTR(SOURCE_TIME_REALTIME))
- r = flush_timer(e, e->realtime.fd, ev_queue[i].events, &e->realtime.next);
- else if (ev_queue[i].data.ptr == INT_TO_PTR(SOURCE_TIME_BOOTTIME))
- r = flush_timer(e, e->boottime.fd, ev_queue[i].events, &e->boottime.next);
- else if (ev_queue[i].data.ptr == INT_TO_PTR(SOURCE_TIME_MONOTONIC))
- r = flush_timer(e, e->monotonic.fd, ev_queue[i].events, &e->monotonic.next);
- else if (ev_queue[i].data.ptr == INT_TO_PTR(SOURCE_TIME_REALTIME_ALARM))
- r = flush_timer(e, e->realtime_alarm.fd, ev_queue[i].events, &e->realtime_alarm.next);
- else if (ev_queue[i].data.ptr == INT_TO_PTR(SOURCE_TIME_BOOTTIME_ALARM))
- r = flush_timer(e, e->boottime_alarm.fd, ev_queue[i].events, &e->boottime_alarm.next);
- else if (ev_queue[i].data.ptr == INT_TO_PTR(SOURCE_SIGNAL))
- r = process_signal(e, ev_queue[i].events);
- else if (ev_queue[i].data.ptr == INT_TO_PTR(SOURCE_WATCHDOG))
+ if (ev_queue[i].data.ptr == INT_TO_PTR(SOURCE_WATCHDOG))
r = flush_timer(e, e->watchdog_fd, ev_queue[i].events, NULL);
- else
- r = process_io(e, ev_queue[i].data.ptr, ev_queue[i].events);
+ else {
+ WakeupType *t = ev_queue[i].data.ptr;
+
+ switch (*t) {
+
+ case WAKEUP_EVENT_SOURCE:
+ r = process_io(e, ev_queue[i].data.ptr, ev_queue[i].events);
+ break;
+ case WAKEUP_CLOCK_DATA: {
+ struct clock_data *d = ev_queue[i].data.ptr;
+ r = flush_timer(e, d->fd, ev_queue[i].events, &d->next);
+ break;
+ }
+
+ case WAKEUP_SIGNAL_DATA:
+ r = process_signal(e, ev_queue[i].data.ptr, ev_queue[i].events);
+ break;
+
+ default:
+ assert_not_reached("Invalid wake-up pointer");
+ }
+ }
if (r < 0)
goto finish;
}
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-11-27 10:27:55 +0000