event: add ability to change fd of an active event source

diff --git a/src/libsystemd-bus/sd-event.c b/src/libsystemd-bus/sd-event.c
index 65ee12d5ff5b7abd155e7cbed3794275e648a989..2b75c6ae9cb759478d65c6f07e414645cfdcf8e1 100644 (file)
--- a/src/libsystemd-bus/sd-event.c
+++ b/src/libsystemd-bus/sd-event.c
@@ -1036,6 +1036,42 @@ _public_ int sd_event_source_get_io_fd(sd_event_source *s) {
         return s->io.fd;
 }
 
         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);
 _public_ int sd_event_source_get_io_events(sd_event_source *s, uint32_t* events) {
         assert_return(s, -EINVAL);
         assert_return(events, -EINVAL);

diff --git a/src/systemd/sd-event.h b/src/systemd/sd-event.h
index cf949be97dfa51d439a2854ef2b885b6dfd90e28..4c1fbf2c33f7c8db31347c8b66ba398d5d9f790f 100644 (file)
--- a/src/systemd/sd-event.h
+++ b/src/systemd/sd-event.h
@@ -108,6 +108,7 @@ int sd_event_source_set_enabled(sd_event_source *s, int enabled);
 void* sd_event_source_get_userdata(sd_event_source *s);
 void* sd_event_source_set_userdata(sd_event_source *s, void *userdata);
 int sd_event_source_get_io_fd(sd_event_source *s);
 void* sd_event_source_get_userdata(sd_event_source *s);
 void* sd_event_source_set_userdata(sd_event_source *s, void *userdata);
 int sd_event_source_get_io_fd(sd_event_source *s);

+int sd_event_source_set_io_fd(sd_event_source *s, int fd);

 int sd_event_source_get_io_events(sd_event_source *s, uint32_t* events);
 int sd_event_source_set_io_events(sd_event_source *s, uint32_t events);
 int sd_event_source_get_io_revents(sd_event_source *s, uint32_t* revents);
 int sd_event_source_get_io_events(sd_event_source *s, uint32_t* events);
 int sd_event_source_set_io_events(sd_event_source *s, uint32_t events);
 int sd_event_source_get_io_revents(sd_event_source *s, uint32_t* revents);