event: add sd_event_source_get_child_pid() call to query the PID of a child event source

1 files changed, 10 insertions, 0 deletions

diff --git a/src/libsystemd-bus/sd-event.c b/src/libsystemd-bus/sd-event.c
index 3094d9e297..482e3bb8a5 100644
--- a/src/libsystemd-bus/sd-event.c
+++ b/src/libsystemd-bus/sd-event.c
@@ -1297,6 +1297,16 @@ int sd_event_source_get_time_accuracy(sd_event_source *s, uint64_t *usec) {
         return 0;
 }
 
+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;
+}
+
 int sd_event_source_set_prepare(sd_event_source *s, sd_prepare_handler_t callback) {
         int r;