s3/smbd: add cleanupd_init_send()/recv()

Previously, without this patch, if cleanupd died for whatever reason, it
would be restarted from smbd. However, if cleanupd initialization
failed and it exitted again, there would be no child entry in smbd for
it and it wouldn't be attempted to restart it again.

This patch adds async send/recv methods for starting cleanupd that will
reschedule restart attempt every second in case initilisation failed.

Bug: https://bugzilla.samba.org/show_bug.cgi?id=12022

Signed-off-by: Ralph Boehme <slow@samba.org>
Reviewed-by: Volker Lendecke <vl@samba.org>

1 files changed, 105 insertions, 3 deletions

diff --git a/source3/smbd/server.c b/source3/smbd/server.c
index 9e3c652e16e..a2ac77e638a 100644
--- a/source3/smbd/server.c
+++ b/source3/smbd/server.c
@@ -542,6 +542,89 @@ static void cleanupd_stopped(struct tevent_req *req)
 	DBG_WARNING("cleanupd stopped: %s\n", nt_errstr(status));
 }
 
+static void cleanupd_init_trigger(struct tevent_req *req);
+
+struct cleanup_init_state {
+	bool ok;
+	struct tevent_context *ev;
+	struct messaging_context *msg;
+	struct server_id *ppid;
+};
+
+static struct tevent_req *cleanupd_init_send(struct tevent_context *ev,
+					     TALLOC_CTX *mem_ctx,
+					     struct messaging_context *msg,
+					     struct server_id *ppid)
+{
+	struct tevent_req *req = NULL;
+	struct tevent_req *subreq = NULL;
+	struct cleanup_init_state *state = NULL;
+
+	req = tevent_req_create(mem_ctx, &state, struct cleanup_init_state);
+	if (req == NULL) {
+		return NULL;
+	}
+
+	*state = (struct cleanup_init_state) {
+		.msg = msg,
+		.ev = ev,
+		.ppid = ppid
+	};
+
+	subreq = tevent_wakeup_send(req, ev, tevent_timeval_current_ofs(0, 0));
+	if (tevent_req_nomem(subreq, req)) {
+		return tevent_req_post(req, ev);
+	}
+
+	tevent_req_set_callback(subreq, cleanupd_init_trigger, req);
+	return req;
+}
+
+static void cleanupd_init_trigger(struct tevent_req *subreq)
+{
+	struct tevent_req *req = tevent_req_callback_data(
+		subreq, struct tevent_req);
+	struct cleanup_init_state *state = tevent_req_data(
+		req, struct cleanup_init_state);
+	bool ok;
+
+	DBG_NOTICE("Triggering cleanupd startup\n");
+
+	ok = tevent_wakeup_recv(subreq);
+	TALLOC_FREE(subreq);
+	if (!ok) {
+		tevent_req_error(req, ENOMEM);
+		return;
+	}
+
+	state->ok = cleanupd_init(state->msg, false, state->ppid);
+	if (state->ok) {
+		DBG_WARNING("cleanupd restarted\n");
+		tevent_req_done(req);
+		return;
+	}
+
+	DBG_NOTICE("cleanupd startup failed, rescheduling\n");
+
+	subreq = tevent_wakeup_send(req, state->ev,
+				    tevent_timeval_current_ofs(1, 0));
+	if (tevent_req_nomem(subreq, req)) {
+		DBG_ERR("scheduling cleanupd restart failed, giving up\n");
+		return;
+	}
+
+	tevent_req_set_callback(subreq, cleanupd_init_trigger, req);
+	return;
+}
+
+static bool cleanupd_init_recv(struct tevent_req *req)
+{
+	struct cleanup_init_state *state = tevent_req_data(
+		req, struct cleanup_init_state);
+
+	return state->ok;
+}
+
 /*
   at most every smbd:cleanuptime seconds (default 20), we scan the BRL
   and locking database for entries to cleanup. As a side effect this
@@ -568,6 +651,18 @@ static void cleanup_timeout_fn(struct tevent_context *event_ctx,
 			   MSG_SMB_UNLOCK, NULL, 0);
 }
 
+static void cleanupd_started(struct tevent_req *req)
+{
+	bool ok;
+
+	ok = cleanupd_init_recv(req);
+	TALLOC_FREE(req);
+	if (!ok) {
+		DBG_ERR("Failed to restart cleanupd, giving up\n");
+		return;
+	}
+}
+
 static void remove_child_pid(struct smbd_parent_context *parent,
 			     pid_t pid,
 			     bool unclean_shutdown)
@@ -593,13 +688,20 @@ static void remove_child_pid(struct smbd_parent_context *parent,
 	}
 
 	if (pid == procid_to_pid(&parent->cleanupd)) {
-		bool ok;
+		struct tevent_req *req;
+
+		server_id_set_disconnected(&parent->cleanupd);
 
 		DBG_WARNING("Restarting cleanupd\n");
-		ok = cleanupd_init(parent->msg_ctx, false, &parent->cleanupd);
-		if (!ok) {
+		req = cleanupd_init_send(messaging_tevent_context(parent->msg_ctx),
+					 parent,
+					 parent->msg_ctx,
+					 &parent->cleanupd);
+		if (req == NULL) {
 			DBG_ERR("Failed to restart cleanupd\n");
+			return;
 		}
+		tevent_req_set_callback(req, cleanupd_started, parent);
 		return;
 	}