s3-prefork: Provide a cleanup function

This way the parent doesn't need to know how to handle dead children and
keeps all of that within the prefork abstraction.

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

3 files changed, 25 insertions, 28 deletions

diff --git a/source3/lib/server_prefork.c b/source3/lib/server_prefork.c
index 211a54b95b..ef76a55486 100644
--- a/source3/lib/server_prefork.c
+++ b/source3/lib/server_prefork.c
@@ -291,29 +291,37 @@ int prefork_count_active_children(struct prefork_pool *pfp, int *total)
 	return a;
 }
 
-/* to be used to finally mark a children as dead, so that it's slot can
- * be reused */
-bool prefork_mark_pid_dead(struct prefork_pool *pfp, pid_t pid)
+void prefork_cleanup_loop(struct prefork_pool *pfp)
 {
+	int status;
+	pid_t pid;
 	int i;
 
+	/* TODO: should we use a process group id wait instead of looping ? */
 	for (i = 0; i < pfp->pool_size; i++) {
-		if (pfp->pool[i].pid == pid) {
+		if (pfp->pool[i].status == PF_WORKER_NONE ||
+		    pfp->pool[i].pid == 0) {
+			continue;
+		}
+
+		pid = sys_waitpid(pfp->pool[i].pid, &status, WNOHANG);
+		if (pid > 0) {
+
 			if (pfp->pool[i].status != PF_WORKER_EXITING) {
-				DEBUG(2, ("pid %d terminated abnormally!\n",
-					  (int)pid));
+				DEBUG(3, ("Child (%d) terminated abnormally:"
+					  " %d\n", (int)pid, status));
+			} else {
+				DEBUG(10, ("Child (%d) terminated with status:"
+					   " %d\n", (int)pid, status));
 			}
 
 			/* reset all fields,
 			 * this makes status = PF_WORK_NONE */
 			memset(&pfp->pool[i], 0,
 				sizeof(struct pf_worker_data));
-
-			return true;
 		}
 	}
 
-	return false;
 }
 
 void prefork_increase_allowed_clients(struct prefork_pool *pfp, int max)
diff --git a/source3/lib/server_prefork.h b/source3/lib/server_prefork.h
index f5c86b4043..f4d03ccca1 100644
--- a/source3/lib/server_prefork.h
+++ b/source3/lib/server_prefork.h
@@ -160,18 +160,14 @@ int prefork_retire_children(struct prefork_pool *pfp,
 * @return The number of children actually serving clients
 */
 int prefork_count_active_children(struct prefork_pool *pfp, int *total);
+
 /**
-* @brief Mark a child structure as free, based on the dead child pid.
-*	 This function is called when the parent gets back notice a child
-*	 has died through waitpid. It is critical to call this function
-*	 when children are reaped so that memory slots can be freed.
+* @brief Perform cleanups, like waiting (WNOHANG) dead children.
+*	 MUST be called regularly from the parent main loop.
 *
 * @param pfp	The pool.
-* @param pid	The child pid.
-*
-* @return True if the slot was clared. False if the pid is not listed.
 */
-bool prefork_mark_pid_dead(struct prefork_pool *pfp, pid_t pid);
+void prefork_cleanup_loop(struct prefork_pool *pfp);
 
 /**
 * @brief Inform all children that they are allowed to accept 'max' clients
diff --git a/source3/printing/spoolssd.c b/source3/printing/spoolssd.c
index 25223c94c5..27704dab3c 100644
--- a/source3/printing/spoolssd.c
+++ b/source3/printing/spoolssd.c
@@ -524,23 +524,16 @@ static void spoolssd_sig_chld_handler(struct tevent_context *ev_ctx,
 				      void *siginfo, void *pvt)
 {
 	struct prefork_pool *pfp;
-	pid_t pid;
-	int status;
-	bool ok;
 	int active, total;
 	int n, r;
 
 	pfp = talloc_get_type_abort(pvt, struct prefork_pool);
 
-	while ((pid = sys_waitpid(-1, &status, WNOHANG)) > 0) {
-		ok = prefork_mark_pid_dead(pfp, pid);
-		if (!ok) {
-			DEBUG(1, ("Pid %d was not found in children pool!\n",
-				  (int)pid));
-		}
-	}
+	/* run the cleanup function to make sure all dead children are
+	 * properly and timely retired. */
+	prefork_cleanup_loop(pfp);
 
-	/* now check we do not descent below the minimum */
+	/* now check we do not descend below the minimum */
 	active = prefork_count_active_children(pfp, &total);
 
 	n = 0;