From 2d905c846029d1aefcede24d112af26f653a3f2e Mon Sep 17 00:00:00 2001
From: David du Colombier <0intro@gmail.com>
Date: Sat, 25 Apr 1998 00:00:00 +0000
Subject: [PATCH] Plan 9 from Bell Labs 1998-04-25

---
 port/devproc.c | 20 ++++++++++++++++++--
 port/proc.c    |  2 ++
 2 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/port/devproc.c b/port/devproc.c
index 52d5dd24ebbf1ea93341200fecbe2ada2b5f4f01..0e4a0960907c6ba2fdc2845b6507a80003d88ea9 100644
--- a/port/devproc.c
+++ b/port/devproc.c
@@ -246,11 +246,23 @@ procwstat(Chan *c, char *db)
 }
 
 static int
-procfds(Fgrp *f, char *va, int count, long offset)
+procfds(Proc *p, char *va, int count, long offset)
 {
+	Fgrp *f;
 	Chan *c;
 	int n, i;
 
+	f = p->fgrp;
+	if(f == nil)
+		return 0;
+	if(waserror()){
+		unlock(f);
+		qunlock(&p->debug);
+		nexterror();
+	}
+
+	qlock(&p->debug);
+	lock(f);
 	n = 0;
 	for(i = 0; i <= f->maxfd; i++) {
 		c = f->fd[i];
@@ -273,6 +285,10 @@ procfds(Fgrp *f, char *va, int count, long offset)
 				n = 0;
 		}
 	}
+	unlock(f);
+	qunlock(&p->debug);
+	poperror();
+
 	return n;
 }
 
@@ -519,7 +535,7 @@ procread(Chan *c, void *va, long n, vlong off)
 	case Qnoteid:
 		return readnum(offset, va, n, p->noteid, NUMSIZE);
 	case Qfd:
-		return procfds(p->fgrp, va, n, offset);
+		return procfds(p, va, n, offset);
 	}
 	error(Egreg);
 	return 0;		/* not reached */
diff --git a/port/proc.c b/port/proc.c
index 4203f6c831f9524d4111a8291f3e9ed1418dee90..3d07bc34382a01503bc8fcb961862d1c04500fac 100644
--- a/port/proc.c
+++ b/port/proc.c
@@ -648,9 +648,11 @@ pexit(char *exitstr, int freemem)
 	up->alarm = 0;
 
 	if(up->fgrp){
+		qlock(&up->debug);
 		fgrp = up->fgrp;
 		up->fgrp = nil;
 		closefgrp(fgrp);
+		qunlock(&up->debug);
 	}
 	if(up->egrp)
 		closeegrp(up->egrp);