From 2839760066e578e449ebc8b3d71297b9f79a8c99 Mon Sep 17 00:00:00 2001
From: cinap_lenrek <cinap_lenrek@felloff.net>
Date: Sat, 8 Sep 2018 14:49:00 +0200
Subject: [PATCH] rc: fix Xpipefd unbalancing the redir stack

Xpipefd wants the pipe descriptor to be closed in turfredir(), so
it pushes the redirection, but this breaks Xpopredir after normal
redirection. so we shuffle the Xpipefd redir to the bottom of the
stack.
---
 sys/src/cmd/rc/exec.c     | 15 +++++++++++++++
 sys/src/cmd/rc/fns.h      |  1 +
 sys/src/cmd/rc/havefork.c |  3 ++-
 3 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/sys/src/cmd/rc/exec.c b/sys/src/cmd/rc/exec.c
index 10cb76935..4400e45bc 100644
--- a/sys/src/cmd/rc/exec.c
+++ b/sys/src/cmd/rc/exec.c
@@ -123,6 +123,21 @@ pushredir(int type, int from, int to)
 	runq->redir = rp;
 }
 
+void
+shuffleredir(void)
+{
+	redir **rr, *rp;
+
+	rp = runq->redir;
+	if(rp==0)
+		return;
+	runq->redir = rp->next;
+	rp->next = runq->startredir;
+	for(rr = &runq->redir; *rr != rp->next; rr = &((*rr)->next))
+		;
+	*rr = rp;
+}
+
 var*
 newvar(char *name, var *next)
 {
diff --git a/sys/src/cmd/rc/fns.h b/sys/src/cmd/rc/fns.h
index 1afe9ce38..e06265f65 100644
--- a/sys/src/cmd/rc/fns.h
+++ b/sys/src/cmd/rc/fns.h
@@ -55,6 +55,7 @@ void	readhere(void);
 word*	searchpath(char*);
 void	setstatus(char*);
 void	setvar(char*, word*);
+void	shuffleredir(void);
 void	skipnl(void);
 void	start(code*, int, var*);
 int	truestatus(void);
diff --git a/sys/src/cmd/rc/havefork.c b/sys/src/cmd/rc/havefork.c
index ad5a80298..86d6c91f6 100644
--- a/sys/src/cmd/rc/havefork.c
+++ b/sys/src/cmd/rc/havefork.c
@@ -185,7 +185,8 @@ Xpipefd(void)
 	default:
 		addwaitpid(pid);
 		close(sidefd);
-		pushredir(ROPEN, mainfd, mainfd);	/* isn't this a noop? */
+		pushredir(ROPEN, mainfd, mainfd);
+		shuffleredir();	/* shuffle redir to bottom of stack for turfredir() */
 		strcpy(name, Fdprefix);
 		inttoascii(name+strlen(name), mainfd);
 		pushword(name);