s3-prefork: Fix code to retire children

We have to be more careful when retiring children. We cannot stop
accepting connections as soon as the server tells us to quit because if
max_children is reached and we still have clients connected, the server will
not be able to spawn new children until one exits. And children will not exit
until all the clients closed the connections. So we keep operating past our
recall until we have 0 connections.
Also do not try to recall children that still have >= 1 clients connected, they
couldn't anyway.
Also use messaging to warn children and not SIGHUP.

Signed-off-by: Andreas Schneider <asn@samba.org>
Signed-off-by: Simo Sorce <idra@samba.org>

3 files changed, 16 insertions, 11 deletions

diff --git a/source3/lib/server_prefork.c b/source3/lib/server_prefork.c
index bcb5e0f19e..016f65c5c3 100644
--- a/source3/lib/server_prefork.c
+++ b/source3/lib/server_prefork.c
@@ -240,9 +240,11 @@ static int prefork_sort_oldest(const void *ap, const void *bp)
 	return -1;
 }
 
-int prefork_retire_children(struct prefork_pool *pfp,
+int prefork_retire_children(struct messaging_context *msg_ctx,
+			    struct prefork_pool *pfp,
 			    int num_children, time_t age_limit)
 {
+	const DATA_BLOB ping = data_blob_null;
 	time_t now = time(NULL);
 	struct prefork_oldest *oldest;
 	int i, j;
@@ -267,13 +269,15 @@ int prefork_retire_children(struct prefork_pool *pfp,
 		prefork_sort_oldest);
 
 	for (i = 0, j = 0; i < pfp->pool_size && j < num_children; i++) {
-		if ((pfp->pool[i].status == PF_WORKER_ALIVE ||
-		     pfp->pool[i].status == PF_WORKER_ACCEPTING) &&
-		    pfp->pool[i].started <= age_limit) {
+		if (((pfp->pool[i].status == PF_WORKER_ALIVE) &&
+		     (pfp->pool[i].num_clients < 1)) &&
+		    (pfp->pool[i].started <= age_limit)) {
 			/* tell the child it's time to give up */
 			DEBUG(5, ("Retiring pid %d!\n", pfp->pool[i].pid));
 			pfp->pool[i].cmds = PF_SRV_MSG_EXIT;
-			kill(pfp->pool[i].pid, SIGHUP);
+			messaging_send(msg_ctx,
+					pid_to_procid(pfp->pool[i].pid),
+					MSG_PREFORK_PARENT_EVENT, &ping);
 			j++;
 		}
 	}
@@ -581,12 +585,11 @@ static void prefork_listen_accept_handler(struct tevent_context *ev,
 	req = ctx->req;
 	state = tevent_req_data(ctx->req, struct pf_listen_state);
 
-	if (state->pf->cmds == PF_SRV_MSG_EXIT) {
+	if ((state->pf->cmds == PF_SRV_MSG_EXIT) &&
+	    (state->pf->num_clients <= 0)) {
 		/* We have been asked to exit, so drop here and the next
 		 * child will pick it up */
-		if (state->pf->num_clients <= 0) {
-			state->pf->status = PF_WORKER_EXITING;
-		}
+		state->pf->status = PF_WORKER_EXITING;
 		state->error = EINTR;
 		goto done;
 	}
diff --git a/source3/lib/server_prefork.h b/source3/lib/server_prefork.h
index 17491536ff..1d203e6317 100644
--- a/source3/lib/server_prefork.h
+++ b/source3/lib/server_prefork.h
@@ -152,6 +152,7 @@ int prefork_add_children(struct tevent_context *ev_ctx,
 /**
 * @brief Commands a number of children to stop and exit
 *
+* @param msg_ctx	The messaging context.
 * @param pfp		The pool.
 * @param num_children	The number of children we need to retire.
 * @param age_limit	The minimum age a child has been active to be
@@ -165,7 +166,8 @@ int prefork_add_children(struct tevent_context *ev_ctx,
 *	If all the available children are too young or are busy then it
 *	is possible that none will be asked to stop.
 */
-int prefork_retire_children(struct prefork_pool *pfp,
+int prefork_retire_children(struct messaging_context *msg_ctx,
+			    struct prefork_pool *pfp,
 			    int num_children, time_t age_limit);
 /**
 * @brief Count the number of children
diff --git a/source3/lib/server_prefork_util.c b/source3/lib/server_prefork_util.c
index 01c7994f60..3e14015c81 100644
--- a/source3/lib/server_prefork_util.c
+++ b/source3/lib/server_prefork_util.c
@@ -102,7 +102,7 @@ void pfh_manage_pool(struct tevent_context *ev_ctx,
 			n = total - cfg->min_children;
 		}
 		if (n >= 0) {
-			prefork_retire_children(pool, n,
+			prefork_retire_children(msg_ctx, pool, n,
 						now - cfg->child_min_life);
 		}
 	}