s3:smbd: let smbd/nmbd/winbindd child processes terminate if the parent process died.

This applies to all child processes making use of reinit_after_fork().
It is implemented by establishing a pipe between parent and child.
The child watches for EOF on the read end of the pipe, indidcating
an exited parent.

Pair-Programmed-With: Stefan Metzmacher <metze@samba.org>

1 files changed, 13 insertions, 0 deletions

diff --git a/source3/smbd/server.c b/source3/smbd/server.c
index aa3da1f743..851b4608a7 100644
--- a/source3/smbd/server.c
+++ b/source3/smbd/server.c
@@ -57,6 +57,8 @@ struct smbd_parent_context {
 	/* the list of current child processes */
 	struct smbd_child_pid *children;
 	size_t num_children;
+	/* pipe for detecting death of parent process in child: */
+	int child_pipe[2];
 
 	struct timed_event *cleanup_te;
 };
@@ -1231,6 +1233,17 @@ extern void build_options(bool screen);
 		exit(1);
 	}
 
+	/*
+	 * Do not initialize the parent-child-pipe before becoming
+	 * a daemon: this is used to detect a died parent in the child
+	 * process.
+	 */
+	status = init_before_fork();
+	if (!NT_STATUS_IS_OK(status)) {
+		DEBUG(0, ("init_before_fork failed: %s\n", nt_errstr(status)));
+		exit(1);
+	}
+
 	smbd_server_conn->msg_ctx = msg_ctx;
 
 	parent = talloc_zero(ev_ctx, struct smbd_parent_context);