From b139273d483ad58287481cdfd60a131b95405a3f Mon Sep 17 00:00:00 2001
From: David du Colombier <0intro@gmail.com>
Date: Thu, 21 Jun 1990 00:00:00 +0000
Subject: [PATCH] Plan 9 from Bell Labs 1990-06-21

---
 gnot/dat.h     |  2 +-
 gnot/devpipe.c | 15 +++++-----
 gnot/stream.c  | 74 ++++++++++++++++++++++++--------------------------
 3 files changed, 45 insertions(+), 46 deletions(-)

diff --git a/gnot/dat.h b/gnot/dat.h
index c33f5f950d4b3cd494303e775b2c10c5fd0e4843..4876d16ad1cc98371a6a032b5eb13cd5d5e0978e 100644
--- a/gnot/dat.h
+++ b/gnot/dat.h
@@ -327,7 +327,7 @@ struct Proc
 	ulong	pc;			/* DEBUG only */
 };
 
-#define	NERR	10
+#define	NERR	15
 #define	NNOTE	5
 #define	NFD	100
 struct User
diff --git a/gnot/devpipe.c b/gnot/devpipe.c
index e14f44c0e06dfa5cf93b85171a3c8b9a0c4c3fb1..9df787e1136966acee0ec6085c347c853074a742 100644
--- a/gnot/devpipe.c
+++ b/gnot/devpipe.c
@@ -70,8 +70,10 @@ pipeclone(Chan *c, Chan *nc)
 	 *  up the inuse count of each stream to reflect the
 	 *  pointer from the other stream.
 	 */
-	streamenter(c->stream);
-	streamenter(nc->stream);
+	if(streamenter(c->stream)<0)
+		panic("pipeattach");
+	if(streamenter(nc->stream)<0)
+		panic("pipeattach");
 	return nc;
 }
 
@@ -131,6 +133,7 @@ pipeclose(Chan *c)
 	}
 	streamclose(c);		/* close this stream */
 	streamexit(other, 0);	/* release stream for other half of pipe */
+	poperror();
 }
 
 long
@@ -206,9 +209,7 @@ pipestclose(Queue *q)
 	 *  send a hangup
 	 */
 	q = q->other;
-	if(q->next){
-		bp = allocb(0);
-		bp->type = M_HANGUP;
-		pipeiput(q->next, bp);
-	}
+	bp = allocb(0);
+	bp->type = M_HANGUP;
+	PUTNEXT(q, bp);
 }
diff --git a/gnot/stream.c b/gnot/stream.c
index c14e4a2e02269df5f9a59119b360e0954d29db3c..16ddce2349703f3d938511bb5ec88292e632f8ea 100644
--- a/gnot/stream.c
+++ b/gnot/stream.c
@@ -531,8 +531,12 @@ prepend(Block *bp, int n)
 void
 nullput(Queue *q, Block *bp)
 {
-	freeb(bp);
-	error(0, Ehungup);
+	if(bp->type == M_HANGUP)
+		freeb(bp);
+	else {
+		freeb(bp);
+		error(0, Ehungup);
+	}
 }
 
 /*
@@ -757,21 +761,17 @@ streamexit(Stream *s, int locked)
 
 	if(!locked)
 		lock(s);
-	s->inuse--;
-	if(s->inuse != 0){
-		if(!locked)
-			unlock(s);
-		return;
-	}
-
-	/*
-	 *  ascend the stream freeing the queues
-	 */
-	for(q = s->devq; q; q = nq){
-		nq = q->next;
-		freeq(q);
+	if(s->inuse == 1){
+		/*
+		 *  ascend the stream freeing the queues
+		 */
+		for(q = s->devq; q; q = nq){
+			nq = q->next;
+			freeq(q);
+		}
+		s->id = s->dev = s->type = 0;
 	}
-	s->id = s->dev = s->type = 0;
+	s->inuse--;
 	if(!locked)
 		unlock(s);
 }
@@ -797,29 +797,27 @@ streamclose(Chan *c)
 	 *  decrement the reference count
 	 */
 	lock(s);
-	if(s->opens != 1){
-		s->opens--;
-		unlock(c->stream);
-		return;
-	}
-
-	/*
-	 *  descend the stream closing the queues
-	 */
-	for(q = s->procq; q; q = q->next){
-		if(q->info->close)
-			(*q->info->close)(q->other);
-		if(q == s->devq->other)
-			break;
-	}
-
-	/*
-	 *  ascend the stream flushing the queues
-	 */
-	for(q = s->devq; q; q = nq){
-		nq = q->next;
-		flushq(q);
+	if(s->opens == 1){
+		/*
+		 *  descend the stream closing the queues
+		 */
+		for(q = s->procq; q; q = q->next){
+			if(q->info->close)
+				(*q->info->close)(q->other);
+			/* this may be 2 streams joined device end to device end */
+			if(q == s->devq->other)
+				break;
+		}
+	
+		/*
+		 *  ascend the stream flushing the queues
+		 */
+		for(q = s->devq; q; q = nq){
+			nq = q->next;
+			flushq(q);
+		}
 	}
+	s->opens--;
 
 	/*
 	 *  leave it and free it