From: Tatsuo Ishii <ishii@sraoss.co.jp>
Date: Sun, 17 Sep 2023 11:45:46 +0000 (+0900)
Subject: Fix hung up in pcp_exit_handler of pcp child main.
X-Git-Tag: V4_5_0_BETA1~22
X-Git-Url: http://git.postgresql.org/gitweb/static/help.php?a=commitdiff_plain;h=2ee501190928f149f67dcb537855071091e27caa;p=pgpool2.git

Fix hung up in pcp_exit_handler of pcp child main.

pcp_exit_handler is responsible for waiting for exiting pcp child
process. I suspect it is hung up in the wait loop in regression test
001.

https://www.pgpool.net/pipermail/pgpool-hackers/2023-September/004397.html

So I changed it so that it uses waitpid(2) with WNOHANG option.
---

diff --git a/src/pcp_con/pcp_child.c b/src/pcp_con/pcp_child.c
index 363b6bd30..b1d921141 100644
--- a/src/pcp_con/pcp_child.c
+++ b/src/pcp_con/pcp_child.c
@@ -406,6 +406,7 @@ static RETSIGTYPE
 pcp_exit_handler(int sig)
 {
 	pid_t		wpid;
+	ListCell   *lc;
 
 	POOL_SETMASK(&AuthBlockSig);
 
@@ -420,15 +421,17 @@ pcp_exit_handler(int sig)
 
 	POOL_SETMASK(&UnBlockSig);
 
-	if (list_length(pcp_worker_children) > 0)
+	foreach(lc, pcp_worker_children)
 	{
+		int		pid;
+
 		do
 		{
-			wpid = wait(NULL);
-		} while (wpid > 0 || (wpid == -1 && errno == EINTR));
-
-		list_free(pcp_worker_children);
+			wpid = (pid_t) lfirst_int(lc);
+			pid = waitpid(wpid, NULL, WNOHANG);
+		} while (pid == -1 && errno == EINTR);
 	}
+
 	pcp_worker_children = NULL;
 
 	exit(0);