./move.sh

1 files changed, 2887 insertions, 0 deletions

diff --git a/src/libsystemd/libsystemd-internal/sd-event/sd-event.c b/src/libsystemd/libsystemd-internal/sd-event/sd-event.c
new file mode 100644
index 0000000000..0fec8d71b2
--- /dev/null
+++ b/src/libsystemd/libsystemd-internal/sd-event/sd-event.c
@@ -0,0 +1,2887 @@
+/***
+  This file is part of systemd.
+
+  Copyright 2013 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 <sys/epoll.h>
+#include <sys/timerfd.h>
+#include <sys/wait.h>
+
+#include <systemd/sd-daemon.h>
+#include <systemd/sd-event.h>
+#include <systemd/sd-id128.h>
+
+#include "alloc-util.h"
+#include "fd-util.h"
+#include "hashmap.h"
+#include "list.h"
+#include "macro.h"
+#include "missing.h"
+#include "prioq.h"
+#include "process-util.h"
+#include "set.h"
+#include "signal-util.h"
+#include "string-table.h"
+#include "string-util.h"
+#include "time-util.h"
+#include "util.h"
+
+#define DEFAULT_ACCURACY_USEC (250 * USEC_PER_MSEC)
+
+typedef enum EventSourceType {
+        SOURCE_IO,
+        SOURCE_TIME_REALTIME,
+        SOURCE_TIME_BOOTTIME,
+        SOURCE_TIME_MONOTONIC,
+        SOURCE_TIME_REALTIME_ALARM,
+        SOURCE_TIME_BOOTTIME_ALARM,
+        SOURCE_SIGNAL,
+        SOURCE_CHILD,
+        SOURCE_DEFER,
+        SOURCE_POST,
+        SOURCE_EXIT,
+        SOURCE_WATCHDOG,
+        _SOURCE_EVENT_SOURCE_TYPE_MAX,
+        _SOURCE_EVENT_SOURCE_TYPE_INVALID = -1
+} EventSourceType;
+
+static const char* const event_source_type_table[_SOURCE_EVENT_SOURCE_TYPE_MAX] = {
+        [SOURCE_IO] = "io",
+        [SOURCE_TIME_REALTIME] = "realtime",
+        [SOURCE_TIME_BOOTTIME] = "bootime",
+        [SOURCE_TIME_MONOTONIC] = "monotonic",
+        [SOURCE_TIME_REALTIME_ALARM] = "realtime-alarm",
+        [SOURCE_TIME_BOOTTIME_ALARM] = "boottime-alarm",
+        [SOURCE_SIGNAL] = "signal",
+        [SOURCE_CHILD] = "child",
+        [SOURCE_DEFER] = "defer",
+        [SOURCE_POST] = "post",
+        [SOURCE_EXIT] = "exit",
+        [SOURCE_WATCHDOG] = "watchdog",
+};
+
+DEFINE_PRIVATE_STRING_TABLE_LOOKUP_TO_STRING(event_source_type, int);
+
+/* 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;
+        void *userdata;
+        sd_event_handler_t prepare;
+
+        char *description;
+
+        EventSourceType type:5;
+        int enabled:3;
+        bool pending:1;
+        bool dispatching:1;
+        bool floating:1;
+
+        int64_t priority;
+        unsigned pending_index;
+        unsigned prepare_index;
+        unsigned pending_iteration;
+        unsigned prepare_iteration;
+
+        LIST_FIELDS(sd_event_source, sources);
+
+        union {
+                struct {
+                        sd_event_io_handler_t callback;
+                        int fd;
+                        uint32_t events;
+                        uint32_t revents;
+                        bool registered:1;
+                } io;
+                struct {
+                        sd_event_time_handler_t callback;
+                        usec_t next, accuracy;
+                        unsigned earliest_index;
+                        unsigned latest_index;
+                } time;
+                struct {
+                        sd_event_signal_handler_t callback;
+                        struct signalfd_siginfo siginfo;
+                        int sig;
+                } signal;
+                struct {
+                        sd_event_child_handler_t callback;
+                        siginfo_t siginfo;
+                        pid_t pid;
+                        int options;
+                } child;
+                struct {
+                        sd_event_handler_t callback;
+                } defer;
+                struct {
+                        sd_event_handler_t callback;
+                } post;
+                struct {
+                        sd_event_handler_t callback;
+                        unsigned prioq_index;
+                } exit;
+        };
+};
+
+struct clock_data {
+        WakeupType wakeup;
+        int fd;
+
+        /* For all clocks we maintain two priority queues each, one
+         * ordered for the earliest times the events may be
+         * dispatched, and one ordered by the latest times they must
+         * have been dispatched. The range between the top entries in
+         * the two prioqs is the time window we can freely schedule
+         * wakeups in */
+
+        Prioq *earliest;
+        Prioq *latest;
+        usec_t next;
+
+        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 watchdog_fd;
+
+        Prioq *pending;
+        Prioq *prepare;
+
+        /* timerfd_create() only supports these five clocks so far. We
+         * can add support for more clocks when the kernel learns to
+         * deal with them, too. */
+        struct clock_data realtime;
+        struct clock_data boottime;
+        struct clock_data monotonic;
+        struct clock_data realtime_alarm;
+        struct clock_data boottime_alarm;
+
+        usec_t perturb;
+
+        sd_event_source **signal_sources; /* indexed by signal number */
+        Hashmap *signal_data; /* indexed by priority */
+
+        Hashmap *child_sources;
+        unsigned n_enabled_child_sources;
+
+        Set *post_sources;
+
+        Prioq *exit;
+
+        pid_t original_pid;
+
+        unsigned iteration;
+        dual_timestamp timestamp;
+        usec_t timestamp_boottime;
+        int state;
+
+        bool exit_requested:1;
+        bool need_process_child:1;
+        bool watchdog:1;
+        bool profile_delays:1;
+
+        int exit_code;
+
+        pid_t tid;
+        sd_event **default_event_ptr;
+
+        usec_t watchdog_last, watchdog_period;
+
+        unsigned n_sources;
+
+        LIST_HEAD(sd_event_source, sources);
+
+        usec_t last_run, last_log;
+        unsigned delays[sizeof(usec_t) * 8];
+};
+
+static void source_disconnect(sd_event_source *s);
+
+static int pending_prioq_compare(const void *a, const void *b) {
+        const sd_event_source *x = a, *y = b;
+
+        assert(x->pending);
+        assert(y->pending);
+
+        /* Enabled ones first */
+        if (x->enabled != SD_EVENT_OFF && y->enabled == SD_EVENT_OFF)
+                return -1;
+        if (x->enabled == SD_EVENT_OFF && y->enabled != SD_EVENT_OFF)
+                return 1;
+
+        /* Lower priority values first */
+        if (x->priority < y->priority)
+                return -1;
+        if (x->priority > y->priority)
+                return 1;
+
+        /* Older entries first */
+        if (x->pending_iteration < y->pending_iteration)
+                return -1;
+        if (x->pending_iteration > y->pending_iteration)
+                return 1;
+
+        return 0;
+}
+
+static int prepare_prioq_compare(const void *a, const void *b) {
+        const sd_event_source *x = a, *y = b;
+
+        assert(x->prepare);
+        assert(y->prepare);
+
+        /* Enabled ones first */
+        if (x->enabled != SD_EVENT_OFF && y->enabled == SD_EVENT_OFF)
+                return -1;
+        if (x->enabled == SD_EVENT_OFF && y->enabled != SD_EVENT_OFF)
+                return 1;
+
+        /* Move most recently prepared ones last, so that we can stop
+         * preparing as soon as we hit one that has already been
+         * prepared in the current iteration */
+        if (x->prepare_iteration < y->prepare_iteration)
+                return -1;
+        if (x->prepare_iteration > y->prepare_iteration)
+                return 1;
+
+        /* Lower priority values first */
+        if (x->priority < y->priority)
+                return -1;
+        if (x->priority > y->priority)
+                return 1;
+
+        return 0;
+}
+
+static int earliest_time_prioq_compare(const void *a, const void *b) {
+        const sd_event_source *x = a, *y = b;
+
+        assert(EVENT_SOURCE_IS_TIME(x->type));
+        assert(x->type == y->type);
+
+        /* Enabled ones first */
+        if (x->enabled != SD_EVENT_OFF && y->enabled == SD_EVENT_OFF)
+                return -1;
+        if (x->enabled == SD_EVENT_OFF && y->enabled != SD_EVENT_OFF)
+                return 1;
+
+        /* Move the pending ones to the end */
+        if (!x->pending && y->pending)
+                return -1;
+        if (x->pending && !y->pending)
+                return 1;
+
+        /* Order by time */
+        if (x->time.next < y->time.next)
+                return -1;
+        if (x->time.next > y->time.next)
+                return 1;
+
+        return 0;
+}
+
+static usec_t time_event_source_latest(const sd_event_source *s) {
+        return usec_add(s->time.next, s->time.accuracy);
+}
+
+static int latest_time_prioq_compare(const void *a, const void *b) {
+        const sd_event_source *x = a, *y = b;
+
+        assert(EVENT_SOURCE_IS_TIME(x->type));
+        assert(x->type == y->type);
+
+        /* Enabled ones first */
+        if (x->enabled != SD_EVENT_OFF && y->enabled == SD_EVENT_OFF)
+                return -1;
+        if (x->enabled == SD_EVENT_OFF && y->enabled != SD_EVENT_OFF)
+                return 1;
+
+        /* Move the pending ones to the end */
+        if (!x->pending && y->pending)
+                return -1;
+        if (x->pending && !y->pending)
+                return 1;
+
+        /* Order by time */
+        if (time_event_source_latest(x) < time_event_source_latest(y))
+                return -1;
+        if (time_event_source_latest(x) > time_event_source_latest(y))
+                return 1;
+
+        return 0;
+}
+
+static int exit_prioq_compare(const void *a, const void *b) {
+        const sd_event_source *x = a, *y = b;
+
+        assert(x->type == SOURCE_EXIT);
+        assert(y->type == SOURCE_EXIT);
+
+        /* Enabled ones first */
+        if (x->enabled != SD_EVENT_OFF && y->enabled == SD_EVENT_OFF)
+                return -1;
+        if (x->enabled == SD_EVENT_OFF && y->enabled != SD_EVENT_OFF)
+                return 1;
+
+        /* Lower priority values first */
+        if (x->priority < y->priority)
+                return -1;
+        if (x->priority > y->priority)
+                return 1;
+
+        return 0;
+}
+
+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);
+        prioq_free(d->latest);
+}
+
+static void event_free(sd_event *e) {
+        sd_event_source *s;
+
+        assert(e);
+
+        while ((s = e->sources)) {
+                assert(s->floating);
+                source_disconnect(s);
+                sd_event_source_unref(s);
+        }
+
+        assert(e->n_sources == 0);
+
+        if (e->default_event_ptr)
+                *(e->default_event_ptr) = NULL;
+
+        safe_close(e->epoll_fd);
+        safe_close(e->watchdog_fd);
+
+        free_clock_data(&e->realtime);
+        free_clock_data(&e->boottime);
+        free_clock_data(&e->monotonic);
+        free_clock_data(&e->realtime_alarm);
+        free_clock_data(&e->boottime_alarm);
+
+        prioq_free(e->pending);
+        prioq_free(e->prepare);
+        prioq_free(e->exit);
+
+        free(e->signal_sources);
+        hashmap_free(e->signal_data);
+
+        hashmap_free(e->child_sources);
+        set_free(e->post_sources);
+        free(e);
+}
+
+_public_ int sd_event_new(sd_event** ret) {
+        sd_event *e;
+        int r;
+
+        assert_return(ret, -EINVAL);
+
+        e = new0(sd_event, 1);
+        if (!e)
+                return -ENOMEM;
+
+        e->n_ref = 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;
+
+        r = prioq_ensure_allocated(&e->pending, pending_prioq_compare);
+        if (r < 0)
+                goto fail;
+
+        e->epoll_fd = epoll_create1(EPOLL_CLOEXEC);
+        if (e->epoll_fd < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        if (secure_getenv("SD_EVENT_PROFILE_DELAYS")) {
+                log_debug("Event loop profiling enabled. Logarithmic histogram of event loop iterations in the range 2^0 ... 2^63 us will be logged every 5s.");
+                e->profile_delays = true;
+        }
+
+        *ret = e;
+        return 0;
+
+fail:
+        event_free(e);
+        return r;
+}
+
+_public_ sd_event* sd_event_ref(sd_event *e) {
+
+        if (!e)
+                return NULL;
+
+        assert(e->n_ref >= 1);
+        e->n_ref++;
+
+        return e;
+}
+
+_public_ sd_event* sd_event_unref(sd_event *e) {
+
+        if (!e)
+                return NULL;
+
+        assert(e->n_ref >= 1);
+        e->n_ref--;
+
+        if (e->n_ref <= 0)
+                event_free(e);
+
+        return NULL;
+}
+
+static bool event_pid_changed(sd_event *e) {
+        assert(e);
+
+        /* We don't support people creating an event loop and keeping
+         * it around over a fork(). Let's complain. */
+
+        return e->original_pid != getpid();
+}
+
+static void source_io_unregister(sd_event_source *s) {
+        int r;
+
+        assert(s);
+        assert(s->type == SOURCE_IO);
+
+        if (event_pid_changed(s->event))
+                return;
+
+        if (!s->io.registered)
+                return;
+
+        r = epoll_ctl(s->event->epoll_fd, EPOLL_CTL_DEL, s->io.fd, NULL);
+        if (r < 0)
+                log_debug_errno(errno, "Failed to remove source %s (type %s) from epoll: %m",
+                                strna(s->description), event_source_type_to_string(s->type));
+
+        s->io.registered = false;
+}
+
+static int source_io_register(
+                sd_event_source *s,
+                int enabled,
+                uint32_t events) {
+
+        struct epoll_event ev = {};
+        int r;
+
+        assert(s);
+        assert(s->type == SOURCE_IO);
+        assert(enabled != SD_EVENT_OFF);
+
+        ev.events = events;
+        ev.data.ptr = s;
+
+        if (enabled == SD_EVENT_ONESHOT)
+                ev.events |= EPOLLONESHOT;
+
+        if (s->io.registered)
+                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;
+
+        s->io.registered = true;
+
+        return 0;
+}
+
+static clockid_t event_source_type_to_clock(EventSourceType t) {
+
+        switch (t) {
+
+        case SOURCE_TIME_REALTIME:
+                return CLOCK_REALTIME;
+
+        case SOURCE_TIME_BOOTTIME:
+                return CLOCK_BOOTTIME;
+
+        case SOURCE_TIME_MONOTONIC:
+                return CLOCK_MONOTONIC;
+
+        case SOURCE_TIME_REALTIME_ALARM:
+                return CLOCK_REALTIME_ALARM;
+
+        case SOURCE_TIME_BOOTTIME_ALARM:
+                return CLOCK_BOOTTIME_ALARM;
+
+        default:
+                return (clockid_t) -1;
+        }
+}
+
+static EventSourceType clock_to_event_source_type(clockid_t clock) {
+
+        switch (clock) {
+
+        case CLOCK_REALTIME:
+                return SOURCE_TIME_REALTIME;
+
+        case CLOCK_BOOTTIME:
+                return SOURCE_TIME_BOOTTIME;
+
+        case CLOCK_MONOTONIC:
+                return SOURCE_TIME_MONOTONIC;
+
+        case CLOCK_REALTIME_ALARM:
+                return SOURCE_TIME_REALTIME_ALARM;
+
+        case CLOCK_BOOTTIME_ALARM:
+                return SOURCE_TIME_BOOTTIME_ALARM;
+
+        default:
+                return _SOURCE_EVENT_SOURCE_TYPE_INVALID;
+        }
+}
+
+static struct clock_data* event_get_clock_data(sd_event *e, EventSourceType t) {
+        assert(e);
+
+        switch (t) {
+
+        case SOURCE_TIME_REALTIME:
+                return &e->realtime;
+
+        case SOURCE_TIME_BOOTTIME:
+                return &e->boottime;
+
+        case SOURCE_TIME_MONOTONIC:
+                return &e->monotonic;
+
+        case SOURCE_TIME_REALTIME_ALARM:
+                return &e->realtime_alarm;
+
+        case SOURCE_TIME_BOOTTIME_ALARM:
+                return &e->boottime_alarm;
+
+        default:
+                return NULL;
+        }
+}
+
+static int event_make_signal_data(
+                sd_event *e,
+                int sig,
+                struct signal_data **ret) {
+
+        struct epoll_event ev = {};
+        struct signal_data *d;
+        bool added = false;
+        sigset_t ss_copy;
+        int64_t priority;
+        int r;
+
+        assert(e);
+
+        if (event_pid_changed(e))
+                return -ECHILD;
+
+        if (e->signal_sources && e->signal_sources[sig])
+                priority = e->signal_sources[sig]->priority;
+        else
+                priority = 0;
+
+        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) {
+                        free(d);
+                        return 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 (d->fd >= 0) {
+                if (ret)
+                        *ret = d;
+                return 0;
+        }
+
+        d->fd = r;
+
+        ev.events = EPOLLIN;
+        ev.data.ptr = d;
+
+        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) {
+        sd_event *event;
+
+        assert(s);
+
+        if (!s->event)
+                return;
+
+        assert(s->event->n_sources > 0);
+
+        switch (s->type) {
+
+        case SOURCE_IO:
+                if (s->io.fd >= 0)
+                        source_io_unregister(s);
+
+                break;
+
+        case SOURCE_TIME_REALTIME:
+        case SOURCE_TIME_BOOTTIME:
+        case SOURCE_TIME_MONOTONIC:
+        case SOURCE_TIME_REALTIME_ALARM:
+        case SOURCE_TIME_BOOTTIME_ALARM: {
+                struct clock_data *d;
+
+                d = event_get_clock_data(s->event, s->type);
+                assert(d);
+
+                prioq_remove(d->earliest, s, &s->time.earliest_index);
+                prioq_remove(d->latest, s, &s->time.latest_index);
+                d->needs_rearm = true;
+                break;
+        }
+
+        case SOURCE_SIGNAL:
+                if (s->signal.sig > 0) {
+
+                        if (s->event->signal_sources)
+                                s->event->signal_sources[s->signal.sig] = NULL;
+
+                        event_gc_signal_data(s->event, &s->priority, s->signal.sig);
+                }
+
+                break;
+
+        case SOURCE_CHILD:
+                if (s->child.pid > 0) {
+                        if (s->enabled != SD_EVENT_OFF) {
+                                assert(s->event->n_enabled_child_sources > 0);
+                                s->event->n_enabled_child_sources--;
+                        }
+
+                        (void) hashmap_remove(s->event->child_sources, PID_TO_PTR(s->child.pid));
+                        event_gc_signal_data(s->event, &s->priority, SIGCHLD);
+                }
+
+                break;
+
+        case SOURCE_DEFER:
+                /* nothing */
+                break;
+
+        case SOURCE_POST:
+                set_remove(s->event->post_sources, s);
+                break;
+
+        case SOURCE_EXIT:
+                prioq_remove(s->event->exit, s, &s->exit.prioq_index);
+                break;
+
+        default:
+                assert_not_reached("Wut? I shouldn't exist.");
+        }
+
+        if (s->pending)
+                prioq_remove(s->event->pending, s, &s->pending_index);
+
+        if (s->prepare)
+                prioq_remove(s->event->prepare, s, &s->prepare_index);
+
+        event = s->event;
+
+        s->type = _SOURCE_EVENT_SOURCE_TYPE_INVALID;
+        s->event = NULL;
+        LIST_REMOVE(sources, event->sources, s);
+        event->n_sources--;
+
+        if (!s->floating)
+                sd_event_unref(event);
+}
+
+static void source_free(sd_event_source *s) {
+        assert(s);
+
+        source_disconnect(s);
+        free(s->description);
+        free(s);
+}
+
+static int source_set_pending(sd_event_source *s, bool b) {
+        int r;
+
+        assert(s);
+        assert(s->type != SOURCE_EXIT);
+
+        if (s->pending == b)
+                return 0;
+
+        s->pending = b;
+
+        if (b) {
+                s->pending_iteration = s->event->iteration;
+
+                r = prioq_put(s->event->pending, s, &s->pending_index);
+                if (r < 0) {
+                        s->pending = false;
+                        return r;
+                }
+        } else
+                assert_se(prioq_remove(s->event->pending, s, &s->pending_index));
+
+        if (EVENT_SOURCE_IS_TIME(s->type)) {
+                struct clock_data *d;
+
+                d = event_get_clock_data(s->event, s->type);
+                assert(d);
+
+                prioq_reshuffle(d->earliest, s, &s->time.earliest_index);
+                prioq_reshuffle(d->latest, s, &s->time.latest_index);
+                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;
+}
+
+static sd_event_source *source_new(sd_event *e, bool floating, EventSourceType type) {
+        sd_event_source *s;
+
+        assert(e);
+
+        s = new0(sd_event_source, 1);
+        if (!s)
+                return NULL;
+
+        s->n_ref = 1;
+        s->event = e;
+        s->floating = floating;
+        s->type = type;
+        s->pending_index = s->prepare_index = PRIOQ_IDX_NULL;
+
+        if (!floating)
+                sd_event_ref(e);
+
+        LIST_PREPEND(sources, e->sources, s);
+        e->n_sources ++;
+
+        return s;
+}
+
+_public_ int sd_event_add_io(
+                sd_event *e,
+                sd_event_source **ret,
+                int fd,
+                uint32_t events,
+                sd_event_io_handler_t callback,
+                void *userdata) {
+
+        sd_event_source *s;
+        int r;
+
+        assert_return(e, -EINVAL);
+        assert_return(fd >= 0, -EBADF);
+        assert_return(!(events & ~(EPOLLIN|EPOLLOUT|EPOLLRDHUP|EPOLLPRI|EPOLLERR|EPOLLHUP|EPOLLET)), -EINVAL);
+        assert_return(callback, -EINVAL);
+        assert_return(e->state != SD_EVENT_FINISHED, -ESTALE);
+        assert_return(!event_pid_changed(e), -ECHILD);
+
+        s = source_new(e, !ret, SOURCE_IO);
+        if (!s)
+                return -ENOMEM;
+
+        s->wakeup = WAKEUP_EVENT_SOURCE;
+        s->io.fd = fd;
+        s->io.events = events;
+        s->io.callback = callback;
+        s->userdata = userdata;
+        s->enabled = SD_EVENT_ON;
+
+        r = source_io_register(s, s->enabled, events);
+        if (r < 0) {
+                source_free(s);
+                return r;
+        }
+
+        if (ret)
+                *ret = s;
+
+        return 0;
+}
+
+static void initialize_perturb(sd_event *e) {
+        sd_id128_t bootid = {};
+
+        /* When we sleep for longer, we try to realign the wakeup to
+           the same time wihtin each minute/second/250ms, so that
+           events all across the system can be coalesced into a single
+           CPU wakeup. However, let's take some system-specific
+           randomness for this value, so that in a network of systems
+           with synced clocks timer events are distributed a
+           bit. Here, we calculate a perturbation usec offset from the
+           boot ID. */
+
+        if (_likely_(e->perturb != USEC_INFINITY))
+                return;
+
+        if (sd_id128_get_boot(&bootid) >= 0)
+                e->perturb = (bootid.qwords[0] ^ bootid.qwords[1]) % USEC_PER_MINUTE;
+}
+
+static int event_setup_timer_fd(
+                sd_event *e,
+                struct clock_data *d,
+                clockid_t clock) {
+
+        struct epoll_event ev = {};
+        int r, fd;
+
+        assert(e);
+        assert(d);
+
+        if (_likely_(d->fd >= 0))
+                return 0;
+
+        fd = timerfd_create(clock, TFD_NONBLOCK|TFD_CLOEXEC);
+        if (fd < 0)
+                return -errno;
+
+        ev.events = EPOLLIN;
+        ev.data.ptr = d;
+
+        r = epoll_ctl(e->epoll_fd, EPOLL_CTL_ADD, fd, &ev);
+        if (r < 0) {
+                safe_close(fd);
+                return -errno;
+        }
+
+        d->fd = fd;
+        return 0;
+}
+
+static int time_exit_callback(sd_event_source *s, uint64_t usec, void *userdata) {
+        assert(s);
+
+        return sd_event_exit(sd_event_source_get_event(s), PTR_TO_INT(userdata));
+}
+
+_public_ int sd_event_add_time(
+                sd_event *e,
+                sd_event_source **ret,
+                clockid_t clock,
+                uint64_t usec,
+                uint64_t accuracy,
+                sd_event_time_handler_t callback,
+                void *userdata) {
+
+        EventSourceType type;
+        sd_event_source *s;
+        struct clock_data *d;
+        int r;
+
+        assert_return(e, -EINVAL);
+        assert_return(accuracy != (uint64_t) -1, -EINVAL);
+        assert_return(e->state != SD_EVENT_FINISHED, -ESTALE);
+        assert_return(!event_pid_changed(e), -ECHILD);
+
+        if (!callback)
+                callback = time_exit_callback;
+
+        type = clock_to_event_source_type(clock);
+        assert_return(type >= 0, -EOPNOTSUPP);
+
+        d = event_get_clock_data(e, type);
+        assert(d);
+
+        r = prioq_ensure_allocated(&d->earliest, earliest_time_prioq_compare);
+        if (r < 0)
+                return r;
+
+        r = prioq_ensure_allocated(&d->latest, latest_time_prioq_compare);
+        if (r < 0)
+                return r;
+
+        if (d->fd < 0) {
+                r = event_setup_timer_fd(e, d, clock);
+                if (r < 0)
+                        return r;
+        }
+
+        s = source_new(e, !ret, type);
+        if (!s)
+                return -ENOMEM;
+
+        s->time.next = usec;
+        s->time.accuracy = accuracy == 0 ? DEFAULT_ACCURACY_USEC : accuracy;
+        s->time.callback = callback;
+        s->time.earliest_index = s->time.latest_index = PRIOQ_IDX_NULL;
+        s->userdata = userdata;
+        s->enabled = SD_EVENT_ONESHOT;
+
+        d->needs_rearm = true;
+
+        r = prioq_put(d->earliest, s, &s->time.earliest_index);
+        if (r < 0)
+                goto fail;
+
+        r = prioq_put(d->latest, s, &s->time.latest_index);
+        if (r < 0)
+                goto fail;
+
+        if (ret)
+                *ret = s;
+
+        return 0;
+
+fail:
+        source_free(s);
+        return r;
+}
+
+static int signal_exit_callback(sd_event_source *s, const struct signalfd_siginfo *si, void *userdata) {
+        assert(s);
+
+        return sd_event_exit(sd_event_source_get_event(s), PTR_TO_INT(userdata));
+}
+
+_public_ int sd_event_add_signal(
+                sd_event *e,
+                sd_event_source **ret,
+                int sig,
+                sd_event_signal_handler_t callback,
+                void *userdata) {
+
+        sd_event_source *s;
+        struct signal_data *d;
+        sigset_t ss;
+        int r;
+
+        assert_return(e, -EINVAL);
+        assert_return(sig > 0, -EINVAL);
+        assert_return(sig < _NSIG, -EINVAL);
+        assert_return(e->state != SD_EVENT_FINISHED, -ESTALE);
+        assert_return(!event_pid_changed(e), -ECHILD);
+
+        if (!callback)
+                callback = signal_exit_callback;
+
+        r = pthread_sigmask(SIG_SETMASK, NULL, &ss);
+        if (r != 0)
+                return -r;
+
+        if (!sigismember(&ss, sig))
+                return -EBUSY;
+
+        if (!e->signal_sources) {
+                e->signal_sources = new0(sd_event_source*, _NSIG);
+                if (!e->signal_sources)
+                        return -ENOMEM;
+        } else if (e->signal_sources[sig])
+                return -EBUSY;
+
+        s = source_new(e, !ret, SOURCE_SIGNAL);
+        if (!s)
+                return -ENOMEM;
+
+        s->signal.sig = sig;
+        s->signal.callback = callback;
+        s->userdata = userdata;
+        s->enabled = SD_EVENT_ON;
+
+        e->signal_sources[sig] = s;
+
+        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 */
+        (void) sd_event_source_set_description(s, signal_to_string(sig));
+
+        if (ret)
+                *ret = s;
+
+        return 0;
+}
+
+_public_ int sd_event_add_child(
+                sd_event *e,
+                sd_event_source **ret,
+                pid_t pid,
+                int options,
+                sd_event_child_handler_t callback,
+                void *userdata) {
+
+        sd_event_source *s;
+        int r;
+
+        assert_return(e, -EINVAL);
+        assert_return(pid > 1, -EINVAL);
+        assert_return(!(options & ~(WEXITED|WSTOPPED|WCONTINUED)), -EINVAL);
+        assert_return(options != 0, -EINVAL);
+        assert_return(callback, -EINVAL);
+        assert_return(e->state != SD_EVENT_FINISHED, -ESTALE);
+        assert_return(!event_pid_changed(e), -ECHILD);
+
+        r = hashmap_ensure_allocated(&e->child_sources, NULL);
+        if (r < 0)
+                return r;
+
+        if (hashmap_contains(e->child_sources, PID_TO_PTR(pid)))
+                return -EBUSY;
+
+        s = source_new(e, !ret, SOURCE_CHILD);
+        if (!s)
+                return -ENOMEM;
+
+        s->child.pid = pid;
+        s->child.options = options;
+        s->child.callback = callback;
+        s->userdata = userdata;
+        s->enabled = SD_EVENT_ONESHOT;
+
+        r = hashmap_put(e->child_sources, PID_TO_PTR(pid), s);
+        if (r < 0) {
+                source_free(s);
+                return r;
+        }
+
+        e->n_enabled_child_sources ++;
+
+        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;
+
+        if (ret)
+                *ret = s;
+
+        return 0;
+}
+
+_public_ int sd_event_add_defer(
+                sd_event *e,
+                sd_event_source **ret,
+                sd_event_handler_t callback,
+                void *userdata) {
+
+        sd_event_source *s;
+        int r;
+
+        assert_return(e, -EINVAL);
+        assert_return(callback, -EINVAL);
+        assert_return(e->state != SD_EVENT_FINISHED, -ESTALE);
+        assert_return(!event_pid_changed(e), -ECHILD);
+
+        s = source_new(e, !ret, SOURCE_DEFER);
+        if (!s)
+                return -ENOMEM;
+
+        s->defer.callback = callback;
+        s->userdata = userdata;
+        s->enabled = SD_EVENT_ONESHOT;
+
+        r = source_set_pending(s, true);
+        if (r < 0) {
+                source_free(s);
+                return r;
+        }
+
+        if (ret)
+                *ret = s;
+
+        return 0;
+}
+
+_public_ int sd_event_add_post(
+                sd_event *e,
+                sd_event_source **ret,
+                sd_event_handler_t callback,
+                void *userdata) {
+
+        sd_event_source *s;
+        int r;
+
+        assert_return(e, -EINVAL);
+        assert_return(callback, -EINVAL);
+        assert_return(e->state != SD_EVENT_FINISHED, -ESTALE);
+        assert_return(!event_pid_changed(e), -ECHILD);
+
+        r = set_ensure_allocated(&e->post_sources, NULL);
+        if (r < 0)
+                return r;
+
+        s = source_new(e, !ret, SOURCE_POST);
+        if (!s)
+                return -ENOMEM;
+
+        s->post.callback = callback;
+        s->userdata = userdata;
+        s->enabled = SD_EVENT_ON;
+
+        r = set_put(e->post_sources, s);
+        if (r < 0) {
+                source_free(s);
+                return r;
+        }
+
+        if (ret)
+                *ret = s;
+
+        return 0;
+}
+
+_public_ int sd_event_add_exit(
+                sd_event *e,
+                sd_event_source **ret,
+                sd_event_handler_t callback,
+                void *userdata) {
+
+        sd_event_source *s;
+        int r;
+
+        assert_return(e, -EINVAL);
+        assert_return(callback, -EINVAL);
+        assert_return(e->state != SD_EVENT_FINISHED, -ESTALE);
+        assert_return(!event_pid_changed(e), -ECHILD);
+
+        r = prioq_ensure_allocated(&e->exit, exit_prioq_compare);
+        if (r < 0)
+                return r;
+
+        s = source_new(e, !ret, SOURCE_EXIT);
+        if (!s)
+                return -ENOMEM;
+
+        s->exit.callback = callback;
+        s->userdata = userdata;
+        s->exit.prioq_index = PRIOQ_IDX_NULL;
+        s->enabled = SD_EVENT_ONESHOT;
+
+        r = prioq_put(s->event->exit, s, &s->exit.prioq_index);
+        if (r < 0) {
+                source_free(s);
+                return r;
+        }
+
+        if (ret)
+                *ret = s;
+
+        return 0;
+}
+
+_public_ sd_event_source* sd_event_source_ref(sd_event_source *s) {
+
+        if (!s)
+                return NULL;
+
+        assert(s->n_ref >= 1);
+        s->n_ref++;
+
+        return s;
+}
+
+_public_ sd_event_source* sd_event_source_unref(sd_event_source *s) {
+
+        if (!s)
+                return NULL;
+
+        assert(s->n_ref >= 1);
+        s->n_ref--;
+
+        if (s->n_ref <= 0) {
+                /* Here's a special hack: when we are called from a
+                 * dispatch handler we won't free the event source
+                 * immediately, but we will detach the fd from the
+                 * epoll. This way it is safe for the caller to unref
+                 * the event source and immediately close the fd, but
+                 * we still retain a valid event source object after
+                 * the callback. */
+
+                if (s->dispatching) {
+                        if (s->type == SOURCE_IO)
+                                source_io_unregister(s);
+
+                        source_disconnect(s);
+                } else
+                        source_free(s);
+        }
+
+        return NULL;
+}
+
+_public_ int sd_event_source_set_description(sd_event_source *s, const char *description) {
+        assert_return(s, -EINVAL);
+        assert_return(!event_pid_changed(s->event), -ECHILD);
+
+        return free_and_strdup(&s->description, description);
+}
+
+_public_ int sd_event_source_get_description(sd_event_source *s, const char **description) {
+        assert_return(s, -EINVAL);
+        assert_return(description, -EINVAL);
+        assert_return(s->description, -ENXIO);
+        assert_return(!event_pid_changed(s->event), -ECHILD);
+
+        *description = s->description;
+        return 0;
+}
+
+_public_ sd_event *sd_event_source_get_event(sd_event_source *s) {
+        assert_return(s, NULL);
+
+        return s->event;
+}
+
+_public_ int sd_event_source_get_pending(sd_event_source *s) {
+        assert_return(s, -EINVAL);
+        assert_return(s->type != SOURCE_EXIT, -EDOM);
+        assert_return(s->event->state != SD_EVENT_FINISHED, -ESTALE);
+        assert_return(!event_pid_changed(s->event), -ECHILD);
+
+        return s->pending;
+}
+
+_public_ int sd_event_source_get_io_fd(sd_event_source *s) {
+        assert_return(s, -EINVAL);
+        assert_return(s->type == SOURCE_IO, -EDOM);
+        assert_return(!event_pid_changed(s->event), -ECHILD);
+
+        return s->io.fd;
+}
+
+_public_ int sd_event_source_set_io_fd(sd_event_source *s, int fd) {
+        int r;
+
+        assert_return(s, -EINVAL);
+        assert_return(fd >= 0, -EBADF);
+        assert_return(s->type == SOURCE_IO, -EDOM);
+        assert_return(!event_pid_changed(s->event), -ECHILD);
+
+        if (s->io.fd == fd)
+                return 0;
+
+        if (s->enabled == SD_EVENT_OFF) {
+                s->io.fd = fd;
+                s->io.registered = false;
+        } else {
+                int saved_fd;
+
+                saved_fd = s->io.fd;
+                assert(s->io.registered);
+
+                s->io.fd = fd;
+                s->io.registered = false;
+
+                r = source_io_register(s, s->enabled, s->io.events);
+                if (r < 0) {
+                        s->io.fd = saved_fd;
+                        s->io.registered = true;
+                        return r;
+                }
+
+                epoll_ctl(s->event->epoll_fd, EPOLL_CTL_DEL, saved_fd, NULL);
+        }
+
+        return 0;
+}
+
+_public_ int sd_event_source_get_io_events(sd_event_source *s, uint32_t* events) {
+        assert_return(s, -EINVAL);
+        assert_return(events, -EINVAL);
+        assert_return(s->type == SOURCE_IO, -EDOM);
+        assert_return(!event_pid_changed(s->event), -ECHILD);
+
+        *events = s->io.events;
+        return 0;
+}
+
+_public_ int sd_event_source_set_io_events(sd_event_source *s, uint32_t events) {
+        int r;
+
+        assert_return(s, -EINVAL);
+        assert_return(s->type == SOURCE_IO, -EDOM);
+        assert_return(!(events & ~(EPOLLIN|EPOLLOUT|EPOLLRDHUP|EPOLLPRI|EPOLLERR|EPOLLHUP|EPOLLET)), -EINVAL);
+        assert_return(s->event->state != SD_EVENT_FINISHED, -ESTALE);
+        assert_return(!event_pid_changed(s->event), -ECHILD);
+
+        /* edge-triggered updates are never skipped, so we can reset edges */
+        if (s->io.events == events && !(events & EPOLLET))
+                return 0;
+
+        if (s->enabled != SD_EVENT_OFF) {
+                r = source_io_register(s, s->enabled, events);
+                if (r < 0)
+                        return r;
+        }
+
+        s->io.events = events;
+        source_set_pending(s, false);
+
+        return 0;
+}
+
+_public_ int sd_event_source_get_io_revents(sd_event_source *s, uint32_t* revents) {
+        assert_return(s, -EINVAL);
+        assert_return(revents, -EINVAL);
+        assert_return(s->type == SOURCE_IO, -EDOM);
+        assert_return(s->pending, -ENODATA);
+        assert_return(!event_pid_changed(s->event), -ECHILD);
+
+        *revents = s->io.revents;
+        return 0;
+}
+
+_public_ int sd_event_source_get_signal(sd_event_source *s) {
+        assert_return(s, -EINVAL);
+        assert_return(s->type == SOURCE_SIGNAL, -EDOM);
+        assert_return(!event_pid_changed(s->event), -ECHILD);
+
+        return s->signal.sig;
+}
+
+_public_ int sd_event_source_get_priority(sd_event_source *s, int64_t *priority) {
+        assert_return(s, -EINVAL);
+        assert_return(!event_pid_changed(s->event), -ECHILD);
+
+        return s->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);
+
+        if (s->priority == priority)
+                return 0;
+
+        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);
+
+        if (s->prepare)
+                prioq_reshuffle(s->event->prepare, s, &s->prepare_index);
+
+        if (s->type == SOURCE_EXIT)
+                prioq_reshuffle(s->event->exit, s, &s->exit.prioq_index);
+
+        return 0;
+}
+
+_public_ int sd_event_source_get_enabled(sd_event_source *s, int *m) {
+        assert_return(s, -EINVAL);
+        assert_return(m, -EINVAL);
+        assert_return(!event_pid_changed(s->event), -ECHILD);
+
+        *m = s->enabled;
+        return 0;
+}
+
+_public_ int sd_event_source_set_enabled(sd_event_source *s, int m) {
+        int r;
+
+        assert_return(s, -EINVAL);
+        assert_return(m == SD_EVENT_OFF || m == SD_EVENT_ON || m == SD_EVENT_ONESHOT, -EINVAL);
+        assert_return(!event_pid_changed(s->event), -ECHILD);
+
+        /* If we are dead anyway, we are fine with turning off
+         * sources, but everything else needs to fail. */
+        if (s->event->state == SD_EVENT_FINISHED)
+                return m == SD_EVENT_OFF ? 0 : -ESTALE;
+
+        if (s->enabled == m)
+                return 0;
+
+        if (m == SD_EVENT_OFF) {
+
+                switch (s->type) {
+
+                case SOURCE_IO:
+                        source_io_unregister(s);
+                        s->enabled = m;
+                        break;
+
+                case SOURCE_TIME_REALTIME:
+                case SOURCE_TIME_BOOTTIME:
+                case SOURCE_TIME_MONOTONIC:
+                case SOURCE_TIME_REALTIME_ALARM:
+                case SOURCE_TIME_BOOTTIME_ALARM: {
+                        struct clock_data *d;
+
+                        s->enabled = m;
+                        d = event_get_clock_data(s->event, s->type);
+                        assert(d);
+
+                        prioq_reshuffle(d->earliest, s, &s->time.earliest_index);
+                        prioq_reshuffle(d->latest, s, &s->time.latest_index);
+                        d->needs_rearm = true;
+                        break;
+                }
+
+                case SOURCE_SIGNAL:
+                        s->enabled = m;
+
+                        event_gc_signal_data(s->event, &s->priority, s->signal.sig);
+                        break;
+
+                case SOURCE_CHILD:
+                        s->enabled = m;
+
+                        assert(s->event->n_enabled_child_sources > 0);
+                        s->event->n_enabled_child_sources--;
+
+                        event_gc_signal_data(s->event, &s->priority, SIGCHLD);
+                        break;
+
+                case SOURCE_EXIT:
+                        s->enabled = m;
+                        prioq_reshuffle(s->event->exit, s, &s->exit.prioq_index);
+                        break;
+
+                case SOURCE_DEFER:
+                case SOURCE_POST:
+                        s->enabled = m;
+                        break;
+
+                default:
+                        assert_not_reached("Wut? I shouldn't exist.");
+                }
+
+        } else {
+                switch (s->type) {
+
+                case SOURCE_IO:
+                        r = source_io_register(s, m, s->io.events);
+                        if (r < 0)
+                                return r;
+
+                        s->enabled = m;
+                        break;
+
+                case SOURCE_TIME_REALTIME:
+                case SOURCE_TIME_BOOTTIME:
+                case SOURCE_TIME_MONOTONIC:
+                case SOURCE_TIME_REALTIME_ALARM:
+                case SOURCE_TIME_BOOTTIME_ALARM: {
+                        struct clock_data *d;
+
+                        s->enabled = m;
+                        d = event_get_clock_data(s->event, s->type);
+                        assert(d);
+
+                        prioq_reshuffle(d->earliest, s, &s->time.earliest_index);
+                        prioq_reshuffle(d->latest, s, &s->time.latest_index);
+                        d->needs_rearm = true;
+                        break;
+                }
+
+                case SOURCE_SIGNAL:
+
+                        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:
+
+                        if (s->enabled == SD_EVENT_OFF)
+                                s->event->n_enabled_child_sources++;
+
+                        s->enabled = m;
+
+                        r = event_make_signal_data(s->event, SIGCHLD, NULL);
+                        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:
+                        s->enabled = m;
+                        prioq_reshuffle(s->event->exit, s, &s->exit.prioq_index);
+                        break;
+
+                case SOURCE_DEFER:
+                case SOURCE_POST:
+                        s->enabled = m;
+                        break;
+
+                default:
+                        assert_not_reached("Wut? I shouldn't exist.");
+                }
+        }
+
+        if (s->pending)
+                prioq_reshuffle(s->event->pending, s, &s->pending_index);
+
+        if (s->prepare)
+                prioq_reshuffle(s->event->prepare, s, &s->prepare_index);
+
+        return 0;
+}
+
+_public_ int sd_event_source_get_time(sd_event_source *s, uint64_t *usec) {
+        assert_return(s, -EINVAL);
+        assert_return(usec, -EINVAL);
+        assert_return(EVENT_SOURCE_IS_TIME(s->type), -EDOM);
+        assert_return(!event_pid_changed(s->event), -ECHILD);
+
+        *usec = s->time.next;
+        return 0;
+}
+
+_public_ int sd_event_source_set_time(sd_event_source *s, uint64_t usec) {
+        struct clock_data *d;
+
+        assert_return(s, -EINVAL);
+        assert_return(EVENT_SOURCE_IS_TIME(s->type), -EDOM);
+        assert_return(s->event->state != SD_EVENT_FINISHED, -ESTALE);
+        assert_return(!event_pid_changed(s->event), -ECHILD);
+
+        s->time.next = usec;
+
+        source_set_pending(s, false);
+
+        d = event_get_clock_data(s->event, s->type);
+        assert(d);
+
+        prioq_reshuffle(d->earliest, s, &s->time.earliest_index);
+        prioq_reshuffle(d->latest, s, &s->time.latest_index);
+        d->needs_rearm = true;
+
+        return 0;
+}
+
+_public_ int sd_event_source_get_time_accuracy(sd_event_source *s, uint64_t *usec) {
+        assert_return(s, -EINVAL);
+        assert_return(usec, -EINVAL);
+        assert_return(EVENT_SOURCE_IS_TIME(s->type), -EDOM);
+        assert_return(!event_pid_changed(s->event), -ECHILD);
+
+        *usec = s->time.accuracy;
+        return 0;
+}
+
+_public_ int sd_event_source_set_time_accuracy(sd_event_source *s, uint64_t usec) {
+        struct clock_data *d;
+
+        assert_return(s, -EINVAL);
+        assert_return(usec != (uint64_t) -1, -EINVAL);
+        assert_return(EVENT_SOURCE_IS_TIME(s->type), -EDOM);
+        assert_return(s->event->state != SD_EVENT_FINISHED, -ESTALE);
+        assert_return(!event_pid_changed(s->event), -ECHILD);
+
+        if (usec == 0)
+                usec = DEFAULT_ACCURACY_USEC;
+
+        s->time.accuracy = usec;
+
+        source_set_pending(s, false);
+
+        d = event_get_clock_data(s->event, s->type);
+        assert(d);
+
+        prioq_reshuffle(d->latest, s, &s->time.latest_index);
+        d->needs_rearm = true;
+
+        return 0;
+}
+
+_public_ int sd_event_source_get_time_clock(sd_event_source *s, clockid_t *clock) {
+        assert_return(s, -EINVAL);
+        assert_return(clock, -EINVAL);
+        assert_return(EVENT_SOURCE_IS_TIME(s->type), -EDOM);
+        assert_return(!event_pid_changed(s->event), -ECHILD);
+
+        *clock = event_source_type_to_clock(s->type);
+        return 0;
+}
+
+_public_ int sd_event_source_get_child_pid(sd_event_source *s, pid_t *pid) {
+        assert_return(s, -EINVAL);
+        assert_return(pid, -EINVAL);
+        assert_return(s->type == SOURCE_CHILD, -EDOM);
+        assert_return(!event_pid_changed(s->event), -ECHILD);
+
+        *pid = s->child.pid;
+        return 0;
+}
+
+_public_ int sd_event_source_set_prepare(sd_event_source *s, sd_event_handler_t callback) {
+        int r;
+
+        assert_return(s, -EINVAL);
+        assert_return(s->type != SOURCE_EXIT, -EDOM);
+        assert_return(s->event->state != SD_EVENT_FINISHED, -ESTALE);
+        assert_return(!event_pid_changed(s->event), -ECHILD);
+
+        if (s->prepare == callback)
+                return 0;
+
+        if (callback && s->prepare) {
+                s->prepare = callback;
+                return 0;
+        }
+
+        r = prioq_ensure_allocated(&s->event->prepare, prepare_prioq_compare);
+        if (r < 0)
+                return r;
+
+        s->prepare = callback;
+
+        if (callback) {
+                r = prioq_put(s->event->prepare, s, &s->prepare_index);
+                if (r < 0)
+                        return r;
+        } else
+                prioq_remove(s->event->prepare, s, &s->prepare_index);
+
+        return 0;
+}
+
+_public_ void* sd_event_source_get_userdata(sd_event_source *s) {
+        assert_return(s, NULL);
+
+        return s->userdata;
+}
+
+_public_ void *sd_event_source_set_userdata(sd_event_source *s, void *userdata) {
+        void *ret;
+
+        assert_return(s, NULL);
+
+        ret = s->userdata;
+        s->userdata = userdata;
+
+        return ret;
+}
+
+static usec_t sleep_between(sd_event *e, usec_t a, usec_t b) {
+        usec_t c;
+        assert(e);
+        assert(a <= b);
+
+        if (a <= 0)
+                return 0;
+        if (a >= USEC_INFINITY)
+                return USEC_INFINITY;
+
+        if (b <= a + 1)
+                return a;
+
+        initialize_perturb(e);
+
+        /*
+          Find a good time to wake up again between times a and b. We
+          have two goals here:
+
+          a) We want to wake up as seldom as possible, hence prefer
+             later times over earlier times.
+
+          b) But if we have to wake up, then let's make sure to
+             dispatch as much as possible on the entire system.
+
+          We implement this by waking up everywhere at the same time
+          within any given minute if we can, synchronised via the
+          perturbation value determined from the boot ID. If we can't,
+          then we try to find the same spot in every 10s, then 1s and
+          then 250ms step. Otherwise, we pick the last possible time
+          to wake up.
+        */
+
+        c = (b / USEC_PER_MINUTE) * USEC_PER_MINUTE + e->perturb;
+        if (c >= b) {
+                if (_unlikely_(c < USEC_PER_MINUTE))
+                        return b;
+
+                c -= USEC_PER_MINUTE;
+        }
+
+        if (c >= a)
+                return c;
+
+        c = (b / (USEC_PER_SEC*10)) * (USEC_PER_SEC*10) + (e->perturb % (USEC_PER_SEC*10));
+        if (c >= b) {
+                if (_unlikely_(c < USEC_PER_SEC*10))
+                        return b;
+
+                c -= USEC_PER_SEC*10;
+        }
+
+        if (c >= a)
+                return c;
+
+        c = (b / USEC_PER_SEC) * USEC_PER_SEC + (e->perturb % USEC_PER_SEC);
+        if (c >= b) {
+                if (_unlikely_(c < USEC_PER_SEC))
+                        return b;
+
+                c -= USEC_PER_SEC;
+        }
+
+        if (c >= a)
+                return c;
+
+        c = (b / (USEC_PER_MSEC*250)) * (USEC_PER_MSEC*250) + (e->perturb % (USEC_PER_MSEC*250));
+        if (c >= b) {
+                if (_unlikely_(c < USEC_PER_MSEC*250))
+                        return b;
+
+                c -= USEC_PER_MSEC*250;
+        }
+
+        if (c >= a)
+                return c;
+
+        return b;
+}
+
+static int event_arm_timer(
+                sd_event *e,
+                struct clock_data *d) {
+
+        struct itimerspec its = {};
+        sd_event_source *a, *b;
+        usec_t t;
+        int r;
+
+        assert(e);
+        assert(d);
+
+        if (!d->needs_rearm)
+                return 0;
+        else
+                d->needs_rearm = false;
+
+        a = prioq_peek(d->earliest);
+        if (!a || a->enabled == SD_EVENT_OFF || a->time.next == USEC_INFINITY) {
+
+                if (d->fd < 0)
+                        return 0;
+
+                if (d->next == USEC_INFINITY)
+                        return 0;
+
+                /* disarm */
+                r = timerfd_settime(d->fd, TFD_TIMER_ABSTIME, &its, NULL);
+                if (r < 0)
+                        return r;
+
+                d->next = USEC_INFINITY;
+                return 0;
+        }
+
+        b = prioq_peek(d->latest);
+        assert_se(b && b->enabled != SD_EVENT_OFF);
+
+        t = sleep_between(e, a->time.next, time_event_source_latest(b));
+        if (d->next == t)
+                return 0;
+
+        assert_se(d->fd >= 0);
+
+        if (t == 0) {
+                /* We don' want to disarm here, just mean some time looooong ago. */
+                its.it_value.tv_sec = 0;
+                its.it_value.tv_nsec = 1;
+        } else
+                timespec_store(&its.it_value, t);
+
+        r = timerfd_settime(d->fd, TFD_TIMER_ABSTIME, &its, NULL);
+        if (r < 0)
+                return -errno;
+
+        d->next = t;
+        return 0;
+}
+
+static int process_io(sd_event *e, sd_event_source *s, uint32_t revents) {
+        assert(e);
+        assert(s);
+        assert(s->type == SOURCE_IO);
+
+        /* If the event source was already pending, we just OR in the
+         * new revents, otherwise we reset the value. The ORing is
+         * necessary to handle EPOLLONESHOT events properly where
+         * readability might happen independently of writability, and
+         * we need to keep track of both */
+
+        if (s->pending)
+                s->io.revents |= revents;
+        else
+                s->io.revents = revents;
+
+        return source_set_pending(s, true);
+}
+
+static int flush_timer(sd_event *e, int fd, uint32_t events, usec_t *next) {
+        uint64_t x;
+        ssize_t ss;
+
+        assert(e);
+        assert(fd >= 0);
+
+        assert_return(events == EPOLLIN, -EIO);
+
+        ss = read(fd, &x, sizeof(x));
+        if (ss < 0) {
+                if (errno == EAGAIN || errno == EINTR)
+                        return 0;
+
+                return -errno;
+        }
+
+        if (_unlikely_(ss != sizeof(x)))
+                return -EIO;
+
+        if (next)
+                *next = USEC_INFINITY;
+
+        return 0;
+}
+
+static int process_timer(
+                sd_event *e,
+                usec_t n,
+                struct clock_data *d) {
+
+        sd_event_source *s;
+        int r;
+
+        assert(e);
+        assert(d);
+
+        for (;;) {
+                s = prioq_peek(d->earliest);
+                if (!s ||
+                    s->time.next > n ||
+                    s->enabled == SD_EVENT_OFF ||
+                    s->pending)
+                        break;
+
+                r = source_set_pending(s, true);
+                if (r < 0)
+                        return r;
+
+                prioq_reshuffle(d->earliest, s, &s->time.earliest_index);
+                prioq_reshuffle(d->latest, s, &s->time.latest_index);
+                d->needs_rearm = true;
+        }
+
+        return 0;
+}
+
+static int process_child(sd_event *e) {
+        sd_event_source *s;
+        Iterator i;
+        int r;
+
+        assert(e);
+
+        e->need_process_child = false;
+
+        /*
+           So, this is ugly. We iteratively invoke waitid() with P_PID
+           + WNOHANG for each PID we wait for, instead of using
+           P_ALL. This is because we only want to get child
+           information of very specific child processes, and not all
+           of them. We might not have processed the SIGCHLD even of a
+           previous invocation and we don't want to maintain a
+           unbounded *per-child* event queue, hence we really don't
+           want anything flushed out of the kernel's queue that we
+           don't care about. Since this is O(n) this means that if you
+           have a lot of processes you probably want to handle SIGCHLD
+           yourself.
+
+           We do not reap the children here (by using WNOWAIT), this
+           is only done after the event source is dispatched so that
+           the callback still sees the process as a zombie.
+        */
+
+        HASHMAP_FOREACH(s, e->child_sources, i) {
+                assert(s->type == SOURCE_CHILD);
+
+                if (s->pending)
+                        continue;
+
+                if (s->enabled == SD_EVENT_OFF)
+                        continue;
+
+                zero(s->child.siginfo);
+                r = waitid(P_PID, s->child.pid, &s->child.siginfo,
+                           WNOHANG | (s->child.options & WEXITED ? WNOWAIT : 0) | s->child.options);
+                if (r < 0)
+                        return -errno;
+
+                if (s->child.siginfo.si_pid != 0) {
+                        bool zombie =
+                                s->child.siginfo.si_code == CLD_EXITED ||
+                                s->child.siginfo.si_code == CLD_KILLED ||
+                                s->child.siginfo.si_code == CLD_DUMPED;
+
+                        if (!zombie && (s->child.options & WEXITED)) {
+                                /* If the child isn't dead then let's
+                                 * immediately remove the state change
+                                 * from the queue, since there's no
+                                 * benefit in leaving it queued */
+
+                                assert(s->child.options & (WSTOPPED|WCONTINUED));
+                                waitid(P_PID, s->child.pid, &s->child.siginfo, WNOHANG|(s->child.options & (WSTOPPED|WCONTINUED)));
+                        }
+
+                        r = source_set_pending(s, true);
+                        if (r < 0)
+                                return r;
+                }
+        }
+
+        return 0;
+}
+
+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(d->fd, &si, sizeof(si));
+                if (n < 0) {
+                        if (errno == EAGAIN || errno == EINTR)
+                                return read_one;
+
+                        return -errno;
+                }
+
+                if (_unlikely_(n != sizeof(si)))
+                        return -EIO;
+
+                assert(si.ssi_signo < _NSIG);
+
+                read_one = true;
+
+                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;
+        }
+}
+
+static int source_dispatch(sd_event_source *s) {
+        int r = 0;
+
+        assert(s);
+        assert(s->pending || s->type == SOURCE_EXIT);
+
+        if (s->type != SOURCE_DEFER && s->type != SOURCE_EXIT) {
+                r = source_set_pending(s, false);
+                if (r < 0)
+                        return r;
+        }
+
+        if (s->type != SOURCE_POST) {
+                sd_event_source *z;
+                Iterator i;
+
+                /* If we execute a non-post source, let's mark all
+                 * post sources as pending */
+
+                SET_FOREACH(z, s->event->post_sources, i) {
+                        if (z->enabled == SD_EVENT_OFF)
+                                continue;
+
+                        r = source_set_pending(z, true);
+                        if (r < 0)
+                                return r;
+                }
+        }
+
+        if (s->enabled == SD_EVENT_ONESHOT) {
+                r = sd_event_source_set_enabled(s, SD_EVENT_OFF);
+                if (r < 0)
+                        return r;
+        }
+
+        s->dispatching = true;
+
+        switch (s->type) {
+
+        case SOURCE_IO:
+                r = s->io.callback(s, s->io.fd, s->io.revents, s->userdata);
+                break;
+
+        case SOURCE_TIME_REALTIME:
+        case SOURCE_TIME_BOOTTIME:
+        case SOURCE_TIME_MONOTONIC:
+        case SOURCE_TIME_REALTIME_ALARM:
+        case SOURCE_TIME_BOOTTIME_ALARM:
+                r = s->time.callback(s, s->time.next, s->userdata);
+                break;
+
+        case SOURCE_SIGNAL:
+                r = s->signal.callback(s, &s->signal.siginfo, s->userdata);
+                break;
+
+        case SOURCE_CHILD: {
+                bool zombie;
+
+                zombie = s->child.siginfo.si_code == CLD_EXITED ||
+                         s->child.siginfo.si_code == CLD_KILLED ||
+                         s->child.siginfo.si_code == CLD_DUMPED;
+
+                r = s->child.callback(s, &s->child.siginfo, s->userdata);
+
+                /* Now, reap the PID for good. */
+                if (zombie)
+                        waitid(P_PID, s->child.pid, &s->child.siginfo, WNOHANG|WEXITED);
+
+                break;
+        }
+
+        case SOURCE_DEFER:
+                r = s->defer.callback(s, s->userdata);
+                break;
+
+        case SOURCE_POST:
+                r = s->post.callback(s, s->userdata);
+                break;
+
+        case SOURCE_EXIT:
+                r = s->exit.callback(s, s->userdata);
+                break;
+
+        case SOURCE_WATCHDOG:
+        case _SOURCE_EVENT_SOURCE_TYPE_MAX:
+        case _SOURCE_EVENT_SOURCE_TYPE_INVALID:
+                assert_not_reached("Wut? I shouldn't exist.");
+        }
+
+        s->dispatching = false;
+
+        if (r < 0)
+                log_debug_errno(r, "Event source %s (type %s) returned error, disabling: %m",
+                                strna(s->description), event_source_type_to_string(s->type));
+
+        if (s->n_ref == 0)
+                source_free(s);
+        else if (r < 0)
+                sd_event_source_set_enabled(s, SD_EVENT_OFF);
+
+        return 1;
+}
+
+static int event_prepare(sd_event *e) {
+        int r;
+
+        assert(e);
+
+        for (;;) {
+                sd_event_source *s;
+
+                s = prioq_peek(e->prepare);
+                if (!s || s->prepare_iteration == e->iteration || s->enabled == SD_EVENT_OFF)
+                        break;
+
+                s->prepare_iteration = e->iteration;
+                r = prioq_reshuffle(e->prepare, s, &s->prepare_index);
+                if (r < 0)
+                        return r;
+
+                assert(s->prepare);
+
+                s->dispatching = true;
+                r = s->prepare(s, s->userdata);
+                s->dispatching = false;
+
+                if (r < 0)
+                        log_debug_errno(r, "Prepare callback of event source %s (type %s) returned error, disabling: %m",
+                                        strna(s->description), event_source_type_to_string(s->type));
+
+                if (s->n_ref == 0)
+                        source_free(s);
+                else if (r < 0)
+                        sd_event_source_set_enabled(s, SD_EVENT_OFF);
+        }
+
+        return 0;
+}
+
+static int dispatch_exit(sd_event *e) {
+        sd_event_source *p;
+        int r;
+
+        assert(e);
+
+        p = prioq_peek(e->exit);
+        if (!p || p->enabled == SD_EVENT_OFF) {
+                e->state = SD_EVENT_FINISHED;
+                return 0;
+        }
+
+        sd_event_ref(e);
+        e->iteration++;
+        e->state = SD_EVENT_EXITING;
+
+        r = source_dispatch(p);
+
+        e->state = SD_EVENT_INITIAL;
+        sd_event_unref(e);
+
+        return r;
+}
+
+static sd_event_source* event_next_pending(sd_event *e) {
+        sd_event_source *p;
+
+        assert(e);
+
+        p = prioq_peek(e->pending);
+        if (!p)
+                return NULL;
+
+        if (p->enabled == SD_EVENT_OFF)
+                return NULL;
+
+        return p;
+}
+
+static int arm_watchdog(sd_event *e) {
+        struct itimerspec its = {};
+        usec_t t;
+        int r;
+
+        assert(e);
+        assert(e->watchdog_fd >= 0);
+
+        t = sleep_between(e,
+                          e->watchdog_last + (e->watchdog_period / 2),
+                          e->watchdog_last + (e->watchdog_period * 3 / 4));
+
+        timespec_store(&its.it_value, t);
+
+        /* Make sure we never set the watchdog to 0, which tells the
+         * kernel to disable it. */
+        if (its.it_value.tv_sec == 0 && its.it_value.tv_nsec == 0)
+                its.it_value.tv_nsec = 1;
+
+        r = timerfd_settime(e->watchdog_fd, TFD_TIMER_ABSTIME, &its, NULL);
+        if (r < 0)
+                return -errno;
+
+        return 0;
+}
+
+static int process_watchdog(sd_event *e) {
+        assert(e);
+
+        if (!e->watchdog)
+                return 0;
+
+        /* Don't notify watchdog too often */
+        if (e->watchdog_last + e->watchdog_period / 4 > e->timestamp.monotonic)
+                return 0;
+
+        sd_notify(false, "WATCHDOG=1");
+        e->watchdog_last = e->timestamp.monotonic;
+
+        return arm_watchdog(e);
+}
+
+_public_ int sd_event_prepare(sd_event *e) {
+        int r;
+
+        assert_return(e, -EINVAL);
+        assert_return(!event_pid_changed(e), -ECHILD);
+        assert_return(e->state != SD_EVENT_FINISHED, -ESTALE);
+        assert_return(e->state == SD_EVENT_INITIAL, -EBUSY);
+
+        if (e->exit_requested)
+                goto pending;
+
+        e->iteration++;
+
+        e->state = SD_EVENT_PREPARING;
+        r = event_prepare(e);
+        e->state = SD_EVENT_INITIAL;
+        if (r < 0)
+                return r;
+
+        r = event_arm_timer(e, &e->realtime);
+        if (r < 0)
+                return r;
+
+        r = event_arm_timer(e, &e->boottime);
+        if (r < 0)
+                return r;
+
+        r = event_arm_timer(e, &e->monotonic);
+        if (r < 0)
+                return r;
+
+        r = event_arm_timer(e, &e->realtime_alarm);
+        if (r < 0)
+                return r;
+
+        r = event_arm_timer(e, &e->boottime_alarm);
+        if (r < 0)
+                return r;
+
+        if (event_next_pending(e) || e->need_process_child)
+                goto pending;
+
+        e->state = SD_EVENT_ARMED;
+
+        return 0;
+
+pending:
+        e->state = SD_EVENT_ARMED;
+        r = sd_event_wait(e, 0);
+        if (r == 0)
+                e->state = SD_EVENT_ARMED;
+
+        return r;
+}
+
+_public_ int sd_event_wait(sd_event *e, uint64_t timeout) {
+        struct epoll_event *ev_queue;
+        unsigned ev_queue_max;
+        int r, m, i;
+
+        assert_return(e, -EINVAL);
+        assert_return(!event_pid_changed(e), -ECHILD);
+        assert_return(e->state != SD_EVENT_FINISHED, -ESTALE);
+        assert_return(e->state == SD_EVENT_ARMED, -EBUSY);
+
+        if (e->exit_requested) {
+                e->state = SD_EVENT_PENDING;
+                return 1;
+        }
+
+        ev_queue_max = MAX(e->n_sources, 1u);
+        ev_queue = newa(struct epoll_event, ev_queue_max);
+
+        m = epoll_wait(e->epoll_fd, ev_queue, ev_queue_max,
+                       timeout == (uint64_t) -1 ? -1 : (int) ((timeout + USEC_PER_MSEC - 1) / USEC_PER_MSEC));
+        if (m < 0) {
+                if (errno == EINTR) {
+                        e->state = SD_EVENT_PENDING;
+                        return 1;
+                }
+
+                r = -errno;
+                goto finish;
+        }
+
+        dual_timestamp_get(&e->timestamp);
+        e->timestamp_boottime = now(CLOCK_BOOTTIME);
+
+        for (i = 0; i < m; i++) {
+
+                if (ev_queue[i].data.ptr == INT_TO_PTR(SOURCE_WATCHDOG))
+                        r = flush_timer(e, e->watchdog_fd, ev_queue[i].events, NULL);
+                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;
+        }
+
+        r = process_watchdog(e);
+        if (r < 0)
+                goto finish;
+
+        r = process_timer(e, e->timestamp.realtime, &e->realtime);
+        if (r < 0)
+                goto finish;
+
+        r = process_timer(e, e->timestamp_boottime, &e->boottime);
+        if (r < 0)
+                goto finish;
+
+        r = process_timer(e, e->timestamp.monotonic, &e->monotonic);
+        if (r < 0)
+                goto finish;
+
+        r = process_timer(e, e->timestamp.realtime, &e->realtime_alarm);
+        if (r < 0)
+                goto finish;
+
+        r = process_timer(e, e->timestamp_boottime, &e->boottime_alarm);
+        if (r < 0)
+                goto finish;
+
+        if (e->need_process_child) {
+                r = process_child(e);
+                if (r < 0)
+                        goto finish;
+        }
+
+        if (event_next_pending(e)) {
+                e->state = SD_EVENT_PENDING;
+
+                return 1;
+        }
+
+        r = 0;
+
+finish:
+        e->state = SD_EVENT_INITIAL;
+
+        return r;
+}
+
+_public_ int sd_event_dispatch(sd_event *e) {
+        sd_event_source *p;
+        int r;
+
+        assert_return(e, -EINVAL);
+        assert_return(!event_pid_changed(e), -ECHILD);
+        assert_return(e->state != SD_EVENT_FINISHED, -ESTALE);
+        assert_return(e->state == SD_EVENT_PENDING, -EBUSY);
+
+        if (e->exit_requested)
+                return dispatch_exit(e);
+
+        p = event_next_pending(e);
+        if (p) {
+                sd_event_ref(e);
+
+                e->state = SD_EVENT_RUNNING;
+                r = source_dispatch(p);
+                e->state = SD_EVENT_INITIAL;
+
+                sd_event_unref(e);
+
+                return r;
+        }
+
+        e->state = SD_EVENT_INITIAL;
+
+        return 1;
+}
+
+static void event_log_delays(sd_event *e) {
+        char b[ELEMENTSOF(e->delays) * DECIMAL_STR_MAX(unsigned) + 1];
+        unsigned i;
+        int o;
+
+        for (i = o = 0; i < ELEMENTSOF(e->delays); i++) {
+                o += snprintf(&b[o], sizeof(b) - o, "%u ", e->delays[i]);
+                e->delays[i] = 0;
+        }
+        log_debug("Event loop iterations: %.*s", o, b);
+}
+
+_public_ int sd_event_run(sd_event *e, uint64_t timeout) {
+        int r;
+
+        assert_return(e, -EINVAL);
+        assert_return(!event_pid_changed(e), -ECHILD);
+        assert_return(e->state != SD_EVENT_FINISHED, -ESTALE);
+        assert_return(e->state == SD_EVENT_INITIAL, -EBUSY);
+
+        if (e->profile_delays && e->last_run) {
+                usec_t this_run;
+                unsigned l;
+
+                this_run = now(CLOCK_MONOTONIC);
+
+                l = u64log2(this_run - e->last_run);
+                assert(l < sizeof(e->delays));
+                e->delays[l]++;
+
+                if (this_run - e->last_log >= 5*USEC_PER_SEC) {
+                        event_log_delays(e);
+                        e->last_log = this_run;
+                }
+        }
+
+        r = sd_event_prepare(e);
+        if (r == 0)
+                /* There was nothing? Then wait... */
+                r = sd_event_wait(e, timeout);
+
+        if (e->profile_delays)
+                e->last_run = now(CLOCK_MONOTONIC);
+
+        if (r > 0) {
+                /* There's something now, then let's dispatch it */
+                r = sd_event_dispatch(e);
+                if (r < 0)
+                        return r;
+
+                return 1;
+        }
+
+        return r;
+}
+
+_public_ int sd_event_loop(sd_event *e) {
+        int r;
+
+        assert_return(e, -EINVAL);
+        assert_return(!event_pid_changed(e), -ECHILD);
+        assert_return(e->state == SD_EVENT_INITIAL, -EBUSY);
+
+        sd_event_ref(e);
+
+        while (e->state != SD_EVENT_FINISHED) {
+                r = sd_event_run(e, (uint64_t) -1);
+                if (r < 0)
+                        goto finish;
+        }
+
+        r = e->exit_code;
+
+finish:
+        sd_event_unref(e);
+        return r;
+}
+
+_public_ int sd_event_get_fd(sd_event *e) {
+
+        assert_return(e, -EINVAL);
+        assert_return(!event_pid_changed(e), -ECHILD);
+
+        return e->epoll_fd;
+}
+
+_public_ int sd_event_get_state(sd_event *e) {
+        assert_return(e, -EINVAL);
+        assert_return(!event_pid_changed(e), -ECHILD);
+
+        return e->state;
+}
+
+_public_ int sd_event_get_exit_code(sd_event *e, int *code) {
+        assert_return(e, -EINVAL);
+        assert_return(code, -EINVAL);
+        assert_return(!event_pid_changed(e), -ECHILD);
+
+        if (!e->exit_requested)
+                return -ENODATA;
+
+        *code = e->exit_code;
+        return 0;
+}
+
+_public_ int sd_event_exit(sd_event *e, int code) {
+        assert_return(e, -EINVAL);
+        assert_return(e->state != SD_EVENT_FINISHED, -ESTALE);
+        assert_return(!event_pid_changed(e), -ECHILD);
+
+        e->exit_requested = true;
+        e->exit_code = code;
+
+        return 0;
+}
+
+_public_ int sd_event_now(sd_event *e, clockid_t clock, uint64_t *usec) {
+        assert_return(e, -EINVAL);
+        assert_return(usec, -EINVAL);
+        assert_return(!event_pid_changed(e), -ECHILD);
+        assert_return(IN_SET(clock,
+                             CLOCK_REALTIME,
+                             CLOCK_REALTIME_ALARM,
+                             CLOCK_MONOTONIC,
+                             CLOCK_BOOTTIME,
+                             CLOCK_BOOTTIME_ALARM), -EOPNOTSUPP);
+
+        if (!dual_timestamp_is_set(&e->timestamp)) {
+                /* Implicitly fall back to now() if we never ran
+                 * before and thus have no cached time. */
+                *usec = now(clock);
+                return 1;
+        }
+
+        switch (clock) {
+
+        case CLOCK_REALTIME:
+        case CLOCK_REALTIME_ALARM:
+                *usec = e->timestamp.realtime;
+                break;
+
+        case CLOCK_MONOTONIC:
+                *usec = e->timestamp.monotonic;
+                break;
+
+        default:
+                *usec = e->timestamp_boottime;
+                break;
+        }
+
+        return 0;
+}
+
+_public_ int sd_event_default(sd_event **ret) {
+
+        static thread_local sd_event *default_event = NULL;
+        sd_event *e = NULL;
+        int r;
+
+        if (!ret)
+                return !!default_event;
+
+        if (default_event) {
+                *ret = sd_event_ref(default_event);
+                return 0;
+        }
+
+        r = sd_event_new(&e);
+        if (r < 0)
+                return r;
+
+        e->default_event_ptr = &default_event;
+        e->tid = gettid();
+        default_event = e;
+
+        *ret = e;
+        return 1;
+}
+
+_public_ int sd_event_get_tid(sd_event *e, pid_t *tid) {
+        assert_return(e, -EINVAL);
+        assert_return(tid, -EINVAL);
+        assert_return(!event_pid_changed(e), -ECHILD);
+
+        if (e->tid != 0) {
+                *tid = e->tid;
+                return 0;
+        }
+
+        return -ENXIO;
+}
+
+_public_ int sd_event_set_watchdog(sd_event *e, int b) {
+        int r;
+
+        assert_return(e, -EINVAL);
+        assert_return(!event_pid_changed(e), -ECHILD);
+
+        if (e->watchdog == !!b)
+                return e->watchdog;
+
+        if (b) {
+                struct epoll_event ev = {};
+
+                r = sd_watchdog_enabled(false, &e->watchdog_period);
+                if (r <= 0)
+                        return r;
+
+                /* Issue first ping immediately */
+                sd_notify(false, "WATCHDOG=1");
+                e->watchdog_last = now(CLOCK_MONOTONIC);
+
+                e->watchdog_fd = timerfd_create(CLOCK_MONOTONIC, TFD_NONBLOCK|TFD_CLOEXEC);
+                if (e->watchdog_fd < 0)
+                        return -errno;
+
+                r = arm_watchdog(e);
+                if (r < 0)
+                        goto fail;
+
+                ev.events = EPOLLIN;
+                ev.data.ptr = INT_TO_PTR(SOURCE_WATCHDOG);
+
+                r = epoll_ctl(e->epoll_fd, EPOLL_CTL_ADD, e->watchdog_fd, &ev);
+                if (r < 0) {
+                        r = -errno;
+                        goto fail;
+                }
+
+        } else {
+                if (e->watchdog_fd >= 0) {
+                        epoll_ctl(e->epoll_fd, EPOLL_CTL_DEL, e->watchdog_fd, NULL);
+                        e->watchdog_fd = safe_close(e->watchdog_fd);
+                }
+        }
+
+        e->watchdog = !!b;
+        return e->watchdog;
+
+fail:
+        e->watchdog_fd = safe_close(e->watchdog_fd);
+        return r;
+}
+
+_public_ int sd_event_get_watchdog(sd_event *e) {
+        assert_return(e, -EINVAL);
+        assert_return(!event_pid_changed(e), -ECHILD);
+
+        return e->watchdog;
+}