+_public_ int sd_event_source_get_child_pidfd(sd_event_source *s) {
+ assert_return(s, -EINVAL);
+ assert_return(s->type == SOURCE_CHILD, -EDOM);
+ assert_return(!event_pid_changed(s->event), -ECHILD);
+
+ if (s->child.pidfd < 0)
+ return -EOPNOTSUPP;
+
+ return s->child.pidfd;
+}
+
+_public_ int sd_event_source_send_child_signal(sd_event_source *s, int sig, const siginfo_t *si, unsigned flags) {
+ assert_return(s, -EINVAL);
+ assert_return(s->type == SOURCE_CHILD, -EDOM);
+ assert_return(!event_pid_changed(s->event), -ECHILD);
+ assert_return(SIGNAL_VALID(sig), -EINVAL);
+
+ /* If we already have seen indication the process exited refuse sending a signal early. This way we
+ * can be sure we don't accidentally kill the wrong process on PID reuse when pidfds are not
+ * available. */
+ if (s->child.exited)
+ return -ESRCH;
+
+ if (s->child.pidfd >= 0) {
+ siginfo_t copy;
+
+ /* pidfd_send_signal() changes the siginfo_t argument. This is weird, let's hence copy the
+ * structure here */
+ if (si)
+ copy = *si;
+
+ if (pidfd_send_signal(s->child.pidfd, sig, si ? © : NULL, 0) < 0) {
+ /* Let's propagate the error only if the system call is not implemented or prohibited */
+ if (!ERRNO_IS_NOT_SUPPORTED(errno) && !ERRNO_IS_PRIVILEGE(errno))
+ return -errno;
+ } else
+ return 0;
+ }
+
+ /* Flags are only supported for pidfd_send_signal(), not for rt_sigqueueinfo(), hence let's refuse
+ * this here. */
+ if (flags != 0)
+ return -EOPNOTSUPP;
+
+ if (si) {
+ /* We use rt_sigqueueinfo() only if siginfo_t is specified. */
+ siginfo_t copy = *si;
+
+ if (rt_sigqueueinfo(s->child.pid, sig, ©) < 0)
+ return -errno;
+ } else if (kill(s->child.pid, sig) < 0)
+ return -errno;
+
+ return 0;
+}
+
+_public_ int sd_event_source_get_child_pidfd_own(sd_event_source *s) {
+ assert_return(s, -EINVAL);
+ assert_return(s->type == SOURCE_CHILD, -EDOM);
+
+ if (s->child.pidfd < 0)
+ return -EOPNOTSUPP;
+
+ return s->child.pidfd_owned;
+}
+
+_public_ int sd_event_source_set_child_pidfd_own(sd_event_source *s, int own) {
+ assert_return(s, -EINVAL);
+ assert_return(s->type == SOURCE_CHILD, -EDOM);
+
+ if (s->child.pidfd < 0)
+ return -EOPNOTSUPP;
+
+ s->child.pidfd_owned = own;
+ return 0;
+}
+
+_public_ int sd_event_source_get_child_process_own(sd_event_source *s) {
+ assert_return(s, -EINVAL);
+ assert_return(s->type == SOURCE_CHILD, -EDOM);
+
+ return s->child.process_owned;
+}
+
+_public_ int sd_event_source_set_child_process_own(sd_event_source *s, int own) {
+ assert_return(s, -EINVAL);
+ assert_return(s->type == SOURCE_CHILD, -EDOM);
+
+ s->child.process_owned = own;
+ return 0;
+}
+