--- /dev/null
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+ 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 <pthread.h>
+
+#include "sd-id128.h"
+#include "sd-daemon.h"
+#include "macro.h"
+#include "prioq.h"
+#include "hashmap.h"
+#include "util.h"
+#include "time-util.h"
+#include "missing.h"
+
+#include "sd-event.h"
+
+#define EPOLL_QUEUE_MAX 512U
+#define DEFAULT_ACCURACY_USEC (250 * USEC_PER_MSEC)
+
+typedef enum EventSourceType {
+ SOURCE_IO,
+ SOURCE_MONOTONIC,
+ SOURCE_REALTIME,
+ SOURCE_SIGNAL,
+ SOURCE_CHILD,
+ SOURCE_DEFER,
+ SOURCE_EXIT,
+ SOURCE_WATCHDOG
+} EventSourceType;
+
+struct sd_event_source {
+ unsigned n_ref;
+
+ sd_event *event;
+ void *userdata;
+ sd_event_handler_t prepare;
+
+ EventSourceType type:4;
+ int enabled:3;
+ bool pending:1;
+ bool dispatching:1;
+
+ int priority;
+ unsigned pending_index;
+ unsigned prepare_index;
+ unsigned pending_iteration;
+ unsigned prepare_iteration;
+
+ 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;
+ unsigned prioq_index;
+ } exit;
+ };
+};
+
+struct sd_event {
+ unsigned n_ref;
+
+ int epoll_fd;
+ int signal_fd;
+ int realtime_fd;
+ int monotonic_fd;
+ int watchdog_fd;
+
+ Prioq *pending;
+ Prioq *prepare;
+
+ /* For both 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 *monotonic_earliest;
+ Prioq *monotonic_latest;
+ Prioq *realtime_earliest;
+ Prioq *realtime_latest;
+
+ usec_t realtime_next, monotonic_next;
+ usec_t perturb;
+
+ sigset_t sigset;
+ sd_event_source **signal_sources;
+
+ Hashmap *child_sources;
+ unsigned n_enabled_child_sources;
+
+ Prioq *exit;
+
+ pid_t original_pid;
+
+ unsigned iteration;
+ dual_timestamp timestamp;
+ int state;
+
+ bool exit_requested:1;
+ bool need_process_child:1;
+ bool watchdog:1;
+
+ int exit_code;
+
+ pid_t tid;
+ sd_event **default_event_ptr;
+
+ usec_t watchdog_last, watchdog_period;
+
+ unsigned n_sources;
+};
+
+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;
+
+ /* Stability for the rest */
+ if (x < y)
+ return -1;
+ if (x > y)
+ 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);
+
+ /* 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;
+
+ /* 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;
+
+ /* Stability for the rest */
+ if (x < y)
+ return -1;
+ if (x > y)
+ 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(x->type == SOURCE_MONOTONIC || x->type == SOURCE_REALTIME);
+ assert(y->type == SOURCE_MONOTONIC || y->type == SOURCE_REALTIME);
+
+ /* 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;
+
+ /* Stability for the rest */
+ if (x < y)
+ return -1;
+ if (x > y)
+ return 1;
+
+ return 0;
+}
+
+static int latest_time_prioq_compare(const void *a, const void *b) {
+ const sd_event_source *x = a, *y = b;
+
+ assert((x->type == SOURCE_MONOTONIC && y->type == SOURCE_MONOTONIC) ||
+ (x->type == SOURCE_REALTIME && y->type == SOURCE_REALTIME));
+
+ /* 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 + x->time.accuracy < y->time.next + y->time.accuracy)
+ return -1;
+ if (x->time.next + x->time.accuracy > y->time.next + y->time.accuracy)
+ return 1;
+
+ /* Stability for the rest */
+ if (x < y)
+ return -1;
+ if (x > 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;
+
+ /* Stability for the rest */
+ if (x < y)
+ return -1;
+ if (x > y)
+ return 1;
+
+ return 0;
+}
+
+static void event_free(sd_event *e) {
+ assert(e);
+ assert(e->n_sources == 0);
+
+ if (e->default_event_ptr)
+ *(e->default_event_ptr) = NULL;
+
+ if (e->epoll_fd >= 0)
+ close_nointr_nofail(e->epoll_fd);
+
+ if (e->signal_fd >= 0)
+ close_nointr_nofail(e->signal_fd);
+
+ if (e->realtime_fd >= 0)
+ close_nointr_nofail(e->realtime_fd);
+
+ if (e->monotonic_fd >= 0)
+ close_nointr_nofail(e->monotonic_fd);
+
+ if (e->watchdog_fd >= 0)
+ close_nointr_nofail(e->watchdog_fd);
+
+ prioq_free(e->pending);
+ prioq_free(e->prepare);
+ prioq_free(e->monotonic_earliest);
+ prioq_free(e->monotonic_latest);
+ prioq_free(e->realtime_earliest);
+ prioq_free(e->realtime_latest);
+ prioq_free(e->exit);
+
+ free(e->signal_sources);
+
+ hashmap_free(e->child_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->signal_fd = e->realtime_fd = e->monotonic_fd = e->watchdog_fd = e->epoll_fd = -1;
+ e->realtime_next = e->monotonic_next = (usec_t) -1;
+ e->original_pid = getpid();
+
+ assert_se(sigemptyset(&e->sigset) == 0);
+
+ e->pending = prioq_new(pending_prioq_compare);
+ if (!e->pending) {
+ r = -ENOMEM;
+ goto fail;
+ }
+
+ e->epoll_fd = epoll_create1(EPOLL_CLOEXEC);
+ if (e->epoll_fd < 0) {
+ r = -errno;
+ goto fail;
+ }
+
+ *ret = e;
+ return 0;
+
+fail:
+ event_free(e);
+ return r;
+}
+
+_public_ sd_event* sd_event_ref(sd_event *e) {
+ assert_return(e, 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 am event loop and keeping
+ * it around over a fork(). Let's complain. */
+
+ return e->original_pid != getpid();
+}
+
+static int source_io_unregister(sd_event_source *s) {
+ int r;
+
+ assert(s);
+ assert(s->type == SOURCE_IO);
+
+ if (!s->io.registered)
+ return 0;
+
+ r = epoll_ctl(s->event->epoll_fd, EPOLL_CTL_DEL, s->io.fd, NULL);
+ if (r < 0)
+ return -errno;
+
+ s->io.registered = false;
+ return 0;
+}
+
+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 void source_free(sd_event_source *s) {
+ assert(s);
+
+ if (s->event) {
+ assert(s->event->n_sources > 0);
+
+ switch (s->type) {
+
+ case SOURCE_IO:
+ if (s->io.fd >= 0)
+ source_io_unregister(s);
+
+ break;
+
+ case SOURCE_MONOTONIC:
+ prioq_remove(s->event->monotonic_earliest, s, &s->time.earliest_index);
+ prioq_remove(s->event->monotonic_latest, s, &s->time.latest_index);
+ break;
+
+ case SOURCE_REALTIME:
+ prioq_remove(s->event->realtime_earliest, s, &s->time.earliest_index);
+ prioq_remove(s->event->realtime_latest, s, &s->time.latest_index);
+ break;
+
+ case SOURCE_SIGNAL:
+ if (s->signal.sig > 0) {
+ if (s->signal.sig != SIGCHLD || s->event->n_enabled_child_sources == 0)
+ assert_se(sigdelset(&s->event->sigset, s->signal.sig) == 0);
+
+ if (s->event->signal_sources)
+ s->event->signal_sources[s->signal.sig] = NULL;
+ }
+
+ 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--;
+ }
+
+ if (!s->event->signal_sources || !s->event->signal_sources[SIGCHLD])
+ assert_se(sigdelset(&s->event->sigset, SIGCHLD) == 0);
+
+ hashmap_remove(s->event->child_sources, INT_TO_PTR(s->child.pid));
+ }
+
+ break;
+
+ case SOURCE_DEFER:
+ /* nothing */
+ break;
+
+ case SOURCE_EXIT:
+ prioq_remove(s->event->exit, s, &s->exit.prioq_index);
+ break;
+
+ case SOURCE_WATCHDOG:
+ 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);
+
+ s->event->n_sources--;
+ sd_event_unref(s->event);
+ }
+
+ 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 (s->type == SOURCE_REALTIME) {
+ prioq_reshuffle(s->event->realtime_earliest, s, &s->time.earliest_index);
+ prioq_reshuffle(s->event->realtime_latest, s, &s->time.latest_index);
+ } else if (s->type == SOURCE_MONOTONIC) {
+ prioq_reshuffle(s->event->monotonic_earliest, s, &s->time.earliest_index);
+ prioq_reshuffle(s->event->monotonic_latest, s, &s->time.latest_index);
+ }
+
+ return 0;
+}
+
+static sd_event_source *source_new(sd_event *e, EventSourceType type) {
+ sd_event_source *s;
+
+ assert(e);
+
+ s = new0(sd_event_source, 1);
+ if (!s)
+ return NULL;
+
+ s->n_ref = 1;
+ s->event = sd_event_ref(e);
+ s->type = type;
+ s->pending_index = s->prepare_index = PRIOQ_IDX_NULL;
+
+ e->n_sources ++;
+
+ return s;
+}
+
+_public_ int sd_event_add_io(
+ sd_event *e,
+ int fd,
+ uint32_t events,
+ sd_event_io_handler_t callback,
+ void *userdata,
+ sd_event_source **ret) {
+
+ sd_event_source *s;
+ int r;
+
+ assert_return(e, -EINVAL);
+ assert_return(fd >= 0, -EINVAL);
+ assert_return(!(events & ~(EPOLLIN|EPOLLOUT|EPOLLRDHUP|EPOLLPRI|EPOLLERR|EPOLLHUP|EPOLLET)), -EINVAL);
+ assert_return(callback, -EINVAL);
+ assert_return(ret, -EINVAL);
+ assert_return(e->state != SD_EVENT_FINISHED, -ESTALE);
+ assert_return(!event_pid_changed(e), -ECHILD);
+
+ s = source_new(e, SOURCE_IO);
+ if (!s)
+ return -ENOMEM;
+
+ 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 -errno;
+ }
+
+ *ret = s;
+ return 0;
+}
+
+static int event_setup_timer_fd(
+ sd_event *e,
+ EventSourceType type,
+ int *timer_fd,
+ clockid_t id) {
+
+ struct epoll_event ev = {};
+ int r, fd;
+ sd_id128_t bootid;
+
+ assert(e);
+ assert(timer_fd);
+
+ if (_likely_(*timer_fd >= 0))
+ return 0;
+
+ fd = timerfd_create(id, TFD_NONBLOCK|TFD_CLOEXEC);
+ if (fd < 0)
+ return -errno;
+
+ ev.events = EPOLLIN;
+ ev.data.ptr = INT_TO_PTR(type);
+
+ r = epoll_ctl(e->epoll_fd, EPOLL_CTL_ADD, fd, &ev);
+ if (r < 0) {
+ close_nointr_nofail(fd);
+ return -errno;
+ }
+
+ /* 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 (sd_id128_get_boot(&bootid) >= 0)
+ e->perturb = (bootid.qwords[0] ^ bootid.qwords[1]) % USEC_PER_MINUTE;
+
+ *timer_fd = fd;
+ return 0;
+}
+
+static int event_add_time_internal(
+ sd_event *e,
+ EventSourceType type,
+ int *timer_fd,
+ clockid_t id,
+ Prioq **earliest,
+ Prioq **latest,
+ uint64_t usec,
+ uint64_t accuracy,
+ sd_event_time_handler_t callback,
+ void *userdata,
+ sd_event_source **ret) {
+
+ sd_event_source *s;
+ int r;
+
+ assert_return(e, -EINVAL);
+ assert_return(callback, -EINVAL);
+ assert_return(ret, -EINVAL);
+ assert_return(usec != (uint64_t) -1, -EINVAL);
+ assert_return(accuracy != (uint64_t) -1, -EINVAL);
+ assert_return(e->state != SD_EVENT_FINISHED, -ESTALE);
+ assert_return(!event_pid_changed(e), -ECHILD);
+
+ assert(timer_fd);
+ assert(earliest);
+ assert(latest);
+
+ if (!*earliest) {
+ *earliest = prioq_new(earliest_time_prioq_compare);
+ if (!*earliest)
+ return -ENOMEM;
+ }
+
+ if (!*latest) {
+ *latest = prioq_new(latest_time_prioq_compare);
+ if (!*latest)
+ return -ENOMEM;
+ }
+
+ if (*timer_fd < 0) {
+ r = event_setup_timer_fd(e, type, timer_fd, id);
+ if (r < 0)
+ return r;
+ }
+
+ s = source_new(e, 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;
+
+ r = prioq_put(*earliest, s, &s->time.earliest_index);
+ if (r < 0)
+ goto fail;
+
+ r = prioq_put(*latest, s, &s->time.latest_index);
+ if (r < 0)
+ goto fail;
+
+ *ret = s;
+ return 0;
+
+fail:
+ source_free(s);
+ return r;
+}
+
+_public_ int sd_event_add_monotonic(sd_event *e,
+ uint64_t usec,
+ uint64_t accuracy,
+ sd_event_time_handler_t callback,
+ void *userdata,
+ sd_event_source **ret) {
+
+ return event_add_time_internal(e, SOURCE_MONOTONIC, &e->monotonic_fd, CLOCK_MONOTONIC, &e->monotonic_earliest, &e->monotonic_latest, usec, accuracy, callback, userdata, ret);
+}
+
+_public_ int sd_event_add_realtime(sd_event *e,
+ uint64_t usec,
+ uint64_t accuracy,
+ sd_event_time_handler_t callback,
+ void *userdata,
+ sd_event_source **ret) {
+
+ return event_add_time_internal(e, SOURCE_REALTIME, &e->realtime_fd, CLOCK_REALTIME, &e->realtime_earliest, &e->monotonic_latest, usec, accuracy, callback, userdata, ret);
+}
+
+static int event_update_signal_fd(sd_event *e) {
+ struct epoll_event ev = {};
+ bool add_to_epoll;
+ int r;
+
+ assert(e);
+
+ add_to_epoll = e->signal_fd < 0;
+
+ r = signalfd(e->signal_fd, &e->sigset, SFD_NONBLOCK|SFD_CLOEXEC);
+ if (r < 0)
+ return -errno;
+
+ e->signal_fd = r;
+
+ if (!add_to_epoll)
+ return 0;
+
+ ev.events = EPOLLIN;
+ ev.data.ptr = INT_TO_PTR(SOURCE_SIGNAL);
+
+ r = epoll_ctl(e->epoll_fd, EPOLL_CTL_ADD, e->signal_fd, &ev);
+ if (r < 0) {
+ close_nointr_nofail(e->signal_fd);
+ e->signal_fd = -1;
+
+ return -errno;
+ }
+
+ return 0;
+}
+
+_public_ int sd_event_add_signal(
+ sd_event *e,
+ int sig,
+ sd_event_signal_handler_t callback,
+ void *userdata,
+ sd_event_source **ret) {
+
+ sd_event_source *s;
+ sigset_t ss;
+ int r;
+
+ assert_return(e, -EINVAL);
+ assert_return(sig > 0, -EINVAL);
+ assert_return(sig < _NSIG, -EINVAL);
+ assert_return(callback, -EINVAL);
+ assert_return(ret, -EINVAL);
+ assert_return(e->state != SD_EVENT_FINISHED, -ESTALE);
+ assert_return(!event_pid_changed(e), -ECHILD);
+
+ r = pthread_sigmask(SIG_SETMASK, NULL, &ss);
+ if (r < 0)
+ return -errno;
+
+ 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, 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;
+ assert_se(sigaddset(&e->sigset, sig) == 0);
+
+ if (sig != SIGCHLD || e->n_enabled_child_sources == 0) {
+ r = event_update_signal_fd(e);
+ if (r < 0) {
+ source_free(s);
+ return r;
+ }
+ }
+
+ *ret = s;
+ return 0;
+}
+
+_public_ int sd_event_add_child(
+ sd_event *e,
+ pid_t pid,
+ int options,
+ sd_event_child_handler_t callback,
+ void *userdata,
+ sd_event_source **ret) {
+
+ 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(ret, -EINVAL);
+ assert_return(e->state != SD_EVENT_FINISHED, -ESTALE);
+ assert_return(!event_pid_changed(e), -ECHILD);
+
+ r = hashmap_ensure_allocated(&e->child_sources, trivial_hash_func, trivial_compare_func);
+ if (r < 0)
+ return r;
+
+ if (hashmap_contains(e->child_sources, INT_TO_PTR(pid)))
+ return -EBUSY;
+
+ s = source_new(e, 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, INT_TO_PTR(pid), s);
+ if (r < 0) {
+ source_free(s);
+ return r;
+ }
+
+ e->n_enabled_child_sources ++;
+
+ assert_se(sigaddset(&e->sigset, SIGCHLD) == 0);
+
+ if (!e->signal_sources || !e->signal_sources[SIGCHLD]) {
+ r = event_update_signal_fd(e);
+ if (r < 0) {
+ source_free(s);
+ return -errno;
+ }
+ }
+
+ e->need_process_child = true;
+
+ *ret = s;
+ return 0;
+}
+
+_public_ int sd_event_add_defer(
+ sd_event *e,
+ sd_event_handler_t callback,
+ void *userdata,
+ sd_event_source **ret) {
+
+ sd_event_source *s;
+ int r;
+
+ assert_return(e, -EINVAL);
+ assert_return(callback, -EINVAL);
+ assert_return(ret, -EINVAL);
+ assert_return(e->state != SD_EVENT_FINISHED, -ESTALE);
+ assert_return(!event_pid_changed(e), -ECHILD);
+
+ s = source_new(e, 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;
+ }
+
+ *ret = s;
+ return 0;
+}
+
+_public_ int sd_event_add_exit(
+ sd_event *e,
+ sd_event_handler_t callback,
+ void *userdata,
+ sd_event_source **ret) {
+
+ sd_event_source *s;
+ int r;
+
+ assert_return(e, -EINVAL);
+ assert_return(callback, -EINVAL);
+ assert_return(ret, -EINVAL);
+ assert_return(e->state != SD_EVENT_FINISHED, -ESTALE);
+ assert_return(!event_pid_changed(e), -ECHILD);
+
+ if (!e->exit) {
+ e->exit = prioq_new(exit_prioq_compare);
+ if (!e->exit)
+ return -ENOMEM;
+ }
+
+ s = source_new(e, 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;
+ }
+
+ *ret = s;
+ return 0;
+}
+
+_public_ sd_event_source* sd_event_source_ref(sd_event_source *s) {
+ assert_return(s, 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);
+ } else
+ source_free(s);
+ }
+
+ return NULL;
+}
+
+_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, -EINVAL);
+ 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);
+
+ if (s->io.events == events)
+ 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, int *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, int priority) {
+ 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;
+
+ 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(s->event->state != SD_EVENT_FINISHED, -ESTALE);
+ assert_return(!event_pid_changed(s->event), -ECHILD);
+
+ if (s->enabled == m)
+ return 0;
+
+ if (m == SD_EVENT_OFF) {
+
+ switch (s->type) {
+
+ case SOURCE_IO:
+ r = source_io_unregister(s);
+ if (r < 0)
+ return r;
+
+ s->enabled = m;
+ break;
+
+ case SOURCE_MONOTONIC:
+ s->enabled = m;
+ prioq_reshuffle(s->event->monotonic_earliest, s, &s->time.earliest_index);
+ prioq_reshuffle(s->event->monotonic_latest, s, &s->time.latest_index);
+ break;
+
+ case SOURCE_REALTIME:
+ s->enabled = m;
+ prioq_reshuffle(s->event->realtime_earliest, s, &s->time.earliest_index);
+ prioq_reshuffle(s->event->realtime_latest, s, &s->time.latest_index);
+ break;
+
+ case SOURCE_SIGNAL:
+ s->enabled = m;
+ if (s->signal.sig != SIGCHLD || s->event->n_enabled_child_sources == 0) {
+ assert_se(sigdelset(&s->event->sigset, s->signal.sig) == 0);
+ event_update_signal_fd(s->event);
+ }
+
+ break;
+
+ case SOURCE_CHILD:
+ s->enabled = m;
+
+ assert(s->event->n_enabled_child_sources > 0);
+ s->event->n_enabled_child_sources--;
+
+ if (!s->event->signal_sources || !s->event->signal_sources[SIGCHLD]) {
+ assert_se(sigdelset(&s->event->sigset, SIGCHLD) == 0);
+ event_update_signal_fd(s->event);
+ }
+
+ break;
+
+ case SOURCE_EXIT:
+ s->enabled = m;
+ prioq_reshuffle(s->event->exit, s, &s->exit.prioq_index);
+ break;
+
+ case SOURCE_DEFER:
+ s->enabled = m;
+ break;
+
+ case SOURCE_WATCHDOG:
+ 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_MONOTONIC:
+ s->enabled = m;
+ prioq_reshuffle(s->event->monotonic_earliest, s, &s->time.earliest_index);
+ prioq_reshuffle(s->event->monotonic_latest, s, &s->time.latest_index);
+ break;
+
+ case SOURCE_REALTIME:
+ s->enabled = m;
+ prioq_reshuffle(s->event->realtime_earliest, s, &s->time.earliest_index);
+ prioq_reshuffle(s->event->realtime_latest, s, &s->time.latest_index);
+ break;
+
+ case SOURCE_SIGNAL:
+ s->enabled = m;
+
+ if (s->signal.sig != SIGCHLD || s->event->n_enabled_child_sources == 0) {
+ assert_se(sigaddset(&s->event->sigset, s->signal.sig) == 0);
+ event_update_signal_fd(s->event);
+ }
+ break;
+
+ case SOURCE_CHILD:
+ s->enabled = m;
+
+ if (s->enabled == SD_EVENT_OFF) {
+ s->event->n_enabled_child_sources++;
+
+ if (!s->event->signal_sources || !s->event->signal_sources[SIGCHLD]) {
+ assert_se(sigaddset(&s->event->sigset, SIGCHLD) == 0);
+ event_update_signal_fd(s->event);
+ }
+ }
+ break;
+
+ case SOURCE_EXIT:
+ s->enabled = m;
+ prioq_reshuffle(s->event->exit, s, &s->exit.prioq_index);
+ break;
+
+ case SOURCE_DEFER:
+ s->enabled = m;
+ break;
+
+ case SOURCE_WATCHDOG:
+ 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(s->type == SOURCE_REALTIME || s->type == SOURCE_MONOTONIC, -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) {
+ assert_return(s, -EINVAL);
+ assert_return(usec != (uint64_t) -1, -EINVAL);
+ assert_return(s->type == SOURCE_REALTIME || s->type == SOURCE_MONOTONIC, -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);
+
+ if (s->type == SOURCE_REALTIME) {
+ prioq_reshuffle(s->event->realtime_earliest, s, &s->time.earliest_index);
+ prioq_reshuffle(s->event->realtime_latest, s, &s->time.latest_index);
+ } else {
+ prioq_reshuffle(s->event->monotonic_earliest, s, &s->time.earliest_index);
+ prioq_reshuffle(s->event->monotonic_latest, s, &s->time.latest_index);
+ }
+
+ 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(s->type == SOURCE_REALTIME || s->type == SOURCE_MONOTONIC, -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) {
+ assert_return(s, -EINVAL);
+ assert_return(usec != (uint64_t) -1, -EINVAL);
+ assert_return(s->type == SOURCE_REALTIME || s->type == SOURCE_MONOTONIC, -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);
+
+ if (s->type == SOURCE_REALTIME)
+ prioq_reshuffle(s->event->realtime_latest, s, &s->time.latest_index);
+ else
+ prioq_reshuffle(s->event->monotonic_latest, s, &s->time.latest_index);
+
+ 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 (b <= a + 1)
+ return a;
+
+ /*
+ 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,
+ int timer_fd,
+ Prioq *earliest,
+ Prioq *latest,
+ usec_t *next) {
+
+ struct itimerspec its = {};
+ sd_event_source *a, *b;
+ usec_t t;
+ int r;
+
+ assert(e);
+ assert(next);
+
+ a = prioq_peek(earliest);
+ if (!a || a->enabled == SD_EVENT_OFF) {
+
+ if (timer_fd < 0)
+ return 0;
+
+ if (*next == (usec_t) -1)
+ return 0;
+
+ /* disarm */
+ r = timerfd_settime(timer_fd, TFD_TIMER_ABSTIME, &its, NULL);
+ if (r < 0)
+ return r;
+
+ *next = (usec_t) -1;
+
+ return 0;
+ }
+
+ b = prioq_peek(latest);
+ assert_se(b && b->enabled != SD_EVENT_OFF);
+
+ t = sleep_between(e, a->time.next, b->time.next + b->time.accuracy);
+ if (*next == t)
+ return 0;
+
+ assert_se(timer_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(timer_fd, TFD_TIMER_ABSTIME, &its, NULL);
+ if (r < 0)
+ return -errno;
+
+ *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_t) -1;
+
+ return 0;
+}
+
+static int process_timer(
+ sd_event *e,
+ usec_t n,
+ Prioq *earliest,
+ Prioq *latest) {
+
+ sd_event_source *s;
+ int r;
+
+ assert(e);
+
+ for (;;) {
+ s = prioq_peek(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(earliest, s, &s->time.earliest_index);
+ prioq_reshuffle(latest, s, &s->time.latest_index);
+ }
+
+ 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, uint32_t events) {
+ bool read_one = false;
+ int r;
+
+ assert(e);
+ assert(e->signal_sources);
+
+ assert_return(events == EPOLLIN, -EIO);
+
+ for (;;) {
+ struct signalfd_siginfo si;
+ ssize_t ss;
+ sd_event_source *s;
+
+ ss = read(e->signal_fd, &si, sizeof(si));
+ if (ss < 0) {
+ if (errno == EAGAIN || errno == EINTR)
+ return read_one;
+
+ return -errno;
+ }
+
+ if (_unlikely_(ss != sizeof(si)))
+ return -EIO;
+
+ read_one = true;
+
+ s = e->signal_sources[si.ssi_signo];
+ if (si.ssi_signo == SIGCHLD) {
+ r = process_child(e);
+ if (r < 0)
+ return r;
+ if (r > 0 || !s)
+ continue;
+ } else
+ if (!s)
+ return -EIO;
+
+ s->signal.siginfo = si;
+ r = source_set_pending(s, true);
+ if (r < 0)
+ return r;
+ }
+
+ return 0;
+}
+
+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->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_MONOTONIC:
+ r = s->time.callback(s, s->time.next, s->userdata);
+ break;
+
+ case SOURCE_REALTIME:
+ 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_EXIT:
+ r = s->exit.callback(s, s->userdata);
+ break;
+
+ case SOURCE_WATCHDOG:
+ assert_not_reached("Wut? I shouldn't exist.");
+ }
+
+ s->dispatching = false;
+
+ if (r < 0)
+ log_debug("Event source %p returned error, disabling: %s", s, strerror(-r));
+
+ 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("Prepare callback of event source %p returned error, disabling: %s", s, strerror(-r));
+
+ 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_PASSIVE;
+ 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);
+
+ 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_run(sd_event *e, uint64_t timeout) {
+ struct epoll_event *ev_queue;
+ unsigned ev_queue_max;
+ sd_event_source *p;
+ int r, i, m;
+
+ 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_PASSIVE, -EBUSY);
+
+ if (e->exit_requested)
+ return dispatch_exit(e);
+
+ sd_event_ref(e);
+ e->iteration++;
+ e->state = SD_EVENT_RUNNING;
+
+ r = event_prepare(e);
+ if (r < 0)
+ goto finish;
+
+ r = event_arm_timer(e, e->monotonic_fd, e->monotonic_earliest, e->monotonic_latest, &e->monotonic_next);
+ if (r < 0)
+ goto finish;
+
+ r = event_arm_timer(e, e->realtime_fd, e->realtime_earliest, e->realtime_latest, &e->realtime_next);
+ if (r < 0)
+ goto finish;
+
+ if (event_next_pending(e) || e->need_process_child)
+ timeout = 0;
+ ev_queue_max = CLAMP(e->n_sources, 1U, EPOLL_QUEUE_MAX);
+ 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) {
+ r = errno == EAGAIN || errno == EINTR ? 1 : -errno;
+ goto finish;
+ }
+
+ dual_timestamp_get(&e->timestamp);
+
+ for (i = 0; i < m; i++) {
+
+ if (ev_queue[i].data.ptr == INT_TO_PTR(SOURCE_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_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_SIGNAL))
+ r = process_signal(e, ev_queue[i].events);
+ else 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);
+
+ if (r < 0)
+ goto finish;
+ }
+
+ r = process_watchdog(e);
+ if (r < 0)
+ goto finish;
+
+ r = process_timer(e, e->timestamp.monotonic, e->monotonic_earliest, e->monotonic_latest);
+ if (r < 0)
+ goto finish;
+
+ r = process_timer(e, e->timestamp.realtime, e->realtime_earliest, e->realtime_latest);
+ if (r < 0)
+ goto finish;
+
+ if (e->need_process_child) {
+ r = process_child(e);
+ if (r < 0)
+ goto finish;
+ }
+
+ p = event_next_pending(e);
+ if (!p) {
+ r = 1;
+ goto finish;
+ }
+
+ r = source_dispatch(p);
+
+finish:
+ e->state = SD_EVENT_PASSIVE;
+ sd_event_unref(e);
+
+ 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_PASSIVE, -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_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_get_now_realtime(sd_event *e, uint64_t *usec) {
+ assert_return(e, -EINVAL);
+ assert_return(usec, -EINVAL);
+ assert_return(dual_timestamp_is_set(&e->timestamp), -ENODATA);
+ assert_return(!event_pid_changed(e), -ECHILD);
+
+ *usec = e->timestamp.realtime;
+ return 0;
+}
+
+_public_ int sd_event_get_now_monotonic(sd_event *e, uint64_t *usec) {
+ assert_return(e, -EINVAL);
+ assert_return(usec, -EINVAL);
+ assert_return(dual_timestamp_is_set(&e->timestamp), -ENODATA);
+ assert_return(!event_pid_changed(e), -ECHILD);
+
+ *usec = e->timestamp.monotonic;
+ return 0;
+}
+
+_public_ int sd_event_default(sd_event **ret) {
+
+ static thread_local sd_event *default_event = NULL;
+ sd_event *e;
+ 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);
+ close_nointr_nofail(e->watchdog_fd);
+ e->watchdog_fd = -1;
+ }
+ }
+
+ e->watchdog = !!b;
+ return e->watchdog;
+
+fail:
+ close_nointr_nofail(e->watchdog_fd);
+ e->watchdog_fd = -1;
+ 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;
+}
~ianmdlvl / elogind.git / blobdiff