From 35f8ab70be58c726fec4b0156cd9ec880462482a Mon Sep 17 00:00:00 2001
From: Eitan Adler <eadler@FreeBSD.org>
Date: Wed, 30 May 2012 03:55:44 +0000
Subject: [PATCH] Fix likely race condition if wait_child() is interrupted by
 sigchild()

PR:		bin/102834
Submitted by:	Andreas Longwitz <longwitz@incore.de>
Approved by:	cperciva
MFC after:	2 weeks
---
 usr.bin/mail/popen.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/usr.bin/mail/popen.c b/usr.bin/mail/popen.c
index 18bf7e5a3aa5..c4d17461e48d 100644
--- a/usr.bin/mail/popen.c
+++ b/usr.bin/mail/popen.c
@@ -336,12 +336,14 @@ int
 wait_child(int pid)
 {
 	sigset_t nset, oset;
-	struct child *cp = findchild(pid);
+	struct child *cp;
 
 	(void)sigemptyset(&nset);
 	(void)sigaddset(&nset, SIGCHLD);
 	(void)sigprocmask(SIG_BLOCK, &nset, &oset);	
 
+	cp = findchild(pid);
+
 	while (!cp->done)
 		(void)sigsuspend(&oset);
 	wait_status = cp->status;