From ddfde737b546c17e54182028153aa7f7e78804e3 Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Fri, 23 Oct 2020 21:21:58 +0200 Subject: [PATCH] sd-event: split out enable and disable codepaths from sd_event_source_set_enabled() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit So far half of sd_event_source_set_enabled() was doing enabling, the other half was doing disabling. Let's split that into two separate calls. (This also adds a new shortcut to sd_event_source_set_enabled(): if the caller toggles between "ON" and "ONESHOT" we'll now shortcut this, since the event source is already enabled in that case and shall remain enabled.) This heavily borrows and is inspired from Michal Sekletár's #17284 refactoring. --- src/libsystemd/sd-event/sd-event.c | 305 +++++++++++++++-------------- 1 file changed, 159 insertions(+), 146 deletions(-) diff --git a/src/libsystemd/sd-event/sd-event.c b/src/libsystemd/sd-event/sd-event.c index 69032661da..50ee29ae97 100644 --- a/src/libsystemd/sd-event/sd-event.c +++ b/src/libsystemd/sd-event/sd-event.c @@ -2252,6 +2252,152 @@ _public_ int sd_event_source_get_enabled(sd_event_source *s, int *m) { return s->enabled != SD_EVENT_OFF; } +static int event_source_disable(sd_event_source *s) { + int r; + + assert(s); + assert(s->enabled != SD_EVENT_OFF); + + /* Unset the pending flag when this event source is disabled */ + if (!IN_SET(s->type, SOURCE_DEFER, SOURCE_EXIT)) { + r = source_set_pending(s, false); + if (r < 0) + return r; + } + + s->enabled = SD_EVENT_OFF; + + switch (s->type) { + + case SOURCE_IO: + 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: + event_source_time_prioq_reshuffle(s); + break; + + case SOURCE_SIGNAL: + event_gc_signal_data(s->event, &s->priority, s->signal.sig); + break; + + case SOURCE_CHILD: + assert(s->event->n_enabled_child_sources > 0); + s->event->n_enabled_child_sources--; + + if (EVENT_SOURCE_WATCH_PIDFD(s)) + source_child_pidfd_unregister(s); + else + event_gc_signal_data(s->event, &s->priority, SIGCHLD); + break; + + case SOURCE_EXIT: + prioq_reshuffle(s->event->exit, s, &s->exit.prioq_index); + break; + + case SOURCE_DEFER: + case SOURCE_POST: + case SOURCE_INOTIFY: + break; + + default: + assert_not_reached("Wut? I shouldn't exist."); + } + + return 0; +} + +static int event_source_enable(sd_event_source *s, int m) { + int r; + + assert(s); + assert(IN_SET(m, SD_EVENT_ON, SD_EVENT_ONESHOT)); + assert(s->enabled == SD_EVENT_OFF); + + /* Unset the pending flag when this event source is enabled */ + if (!IN_SET(s->type, SOURCE_DEFER, SOURCE_EXIT)) { + r = source_set_pending(s, false); + if (r < 0) + return r; + } + + s->enabled = m; + + switch (s->type) { + + case SOURCE_IO: + r = source_io_register(s, m, s->io.events); + if (r < 0) { + s->enabled = SD_EVENT_OFF; + return r; + } + + break; + + case SOURCE_TIME_REALTIME: + case SOURCE_TIME_BOOTTIME: + case SOURCE_TIME_MONOTONIC: + case SOURCE_TIME_REALTIME_ALARM: + case SOURCE_TIME_BOOTTIME_ALARM: + event_source_time_prioq_reshuffle(s); + break; + + case SOURCE_SIGNAL: + 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: + s->event->n_enabled_child_sources++; + + if (EVENT_SOURCE_WATCH_PIDFD(s)) { + /* yes, we have pidfd */ + + r = source_child_pidfd_register(s, s->enabled); + if (r < 0) { + s->enabled = SD_EVENT_OFF; + s->event->n_enabled_child_sources--; + return r; + } + } else { + /* no pidfd, or something other to watch for than WEXITED */ + + 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: + prioq_reshuffle(s->event->exit, s, &s->exit.prioq_index); + break; + + case SOURCE_DEFER: + case SOURCE_POST: + case SOURCE_INOTIFY: + break; + + default: + assert_not_reached("Wut? I shouldn't exist."); + } + + return 0; +} + _public_ int sd_event_source_set_enabled(sd_event_source *s, int m) { int r; @@ -2259,162 +2405,29 @@ _public_ int sd_event_source_set_enabled(sd_event_source *s, int m) { assert_return(IN_SET(m, SD_EVENT_OFF, SD_EVENT_ON, 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 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) + if (s->enabled == m) /* No change? */ return 0; - if (m == SD_EVENT_OFF) { - - /* Unset the pending flag when this event source is disabled */ - if (!IN_SET(s->type, SOURCE_DEFER, SOURCE_EXIT)) { - r = source_set_pending(s, false); - if (r < 0) - return r; + if (m == SD_EVENT_OFF) + r = event_source_disable(s); + else { + if (s->enabled != SD_EVENT_OFF) { + /* Switching from "on" to "oneshot" or back? If that's the case, we can take a shortcut, the + * event source is already enabled after all. */ + s->enabled = m; + return 0; } - 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: - s->enabled = m; - event_source_time_prioq_reshuffle(s); - 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--; - - if (EVENT_SOURCE_WATCH_PIDFD(s)) - source_child_pidfd_unregister(s); - else - 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: - case SOURCE_INOTIFY: - s->enabled = m; - break; - - default: - assert_not_reached("Wut? I shouldn't exist."); - } - - } else { - - /* Unset the pending flag when this event source is enabled */ - if (s->enabled == SD_EVENT_OFF && !IN_SET(s->type, SOURCE_DEFER, SOURCE_EXIT)) { - r = source_set_pending(s, false); - if (r < 0) - return r; - } - - 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: - s->enabled = m; - event_source_time_prioq_reshuffle(s); - 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; - - if (EVENT_SOURCE_WATCH_PIDFD(s)) { - /* yes, we have pidfd */ - - r = source_child_pidfd_register(s, s->enabled); - if (r < 0) { - s->enabled = SD_EVENT_OFF; - s->event->n_enabled_child_sources--; - return r; - } - } else { - /* no pidfd, or something other to watch for than WEXITED */ - - 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: - case SOURCE_INOTIFY: - s->enabled = m; - break; - - default: - assert_not_reached("Wut? I shouldn't exist."); - } + r = event_source_enable(s, m); } + if (r < 0) + return r; event_source_pp_prioq_reshuffle(s); - return 0; }