From 88fb928a041ef64948920d393c641bd378b0fcc8 Mon Sep 17 00:00:00 2001
From: David du Colombier <0intro@gmail.com>
Date: Sat, 6 Dec 1997 00:00:00 +0000
Subject: [PATCH] Plan 9 from Bell Labs 1997-12-06

---
 port/devdraw.c | 2 +-
 port/devproc.c | 4 ++++
 port/error.h   | 2 +-
 3 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/port/devdraw.c b/port/devdraw.c
index d0e1d729b24ff6f3dc325c35d0426cb15f305bd1..ee03b3328f37be20ac20bccd4c81b4c66c66ea96 100644
--- a/port/devdraw.c
+++ b/port/devdraw.c
@@ -1531,9 +1531,9 @@ drawmesg(Client *client, void *av, int n)
 			drawrectangle(&r, a+5);
 			if(!rectinrect(r, i->r))
 				error(Ereadoutside);
-			free(client->readdata);
 			c = bytesperline(r, i->ldepth);
 			c *= Dy(r);
+			free(client->readdata);
 			client->readdata = mallocz(c, 0);
 			if(client->readdata == nil)
 				error("readimage malloc failed");
diff --git a/port/devproc.c b/port/devproc.c
index b92b3563e602c52a64db2ccf017751ec730b2165..6da95711a946c6c8afe474c68e9a9206b879e859 100644
--- a/port/devproc.c
+++ b/port/devproc.c
@@ -361,6 +361,8 @@ procread(Chan *c, void *va, long n, ulong offset)
 		rptr = (uchar*)&p->fpsave;
 		rsize = sizeof(FPsave);
 	regread:
+		if(rptr == 0)
+			error(Enoreg);
 		if(offset >= rsize)
 			return 0;
 		if(offset+n > rsize)
@@ -566,6 +568,8 @@ procwrite(Chan *c, void *va, long n, ulong offset)
 			return 0;
 		if(offset+n > sizeof(Ureg))
 			n = sizeof(Ureg) - offset;
+		if(p->dbgreg == 0)
+			error(Enoreg);
 		setregisters(p->dbgreg, (char*)(p->dbgreg)+offset, va, n);
 		break;
 
diff --git a/port/error.h b/port/error.h
index b5191837b7a7b86108d47e8c0419e285b6113429..6f123a2ea6f36214654a0c496b5a01753272e3b3 100644
--- a/port/error.h
+++ b/port/error.h
@@ -51,6 +51,6 @@ extern char Esoverlap[];	/* segments overlap */
 extern char Emouseset[];	/* mouse type already set */
 extern char Erecover[];		/* failed to recover fd */
 extern char Eshort[];		/* i/o count too small */
-extern char Enobitstore[];	/* out of screen memory */
 extern char Egreg[];		/* ken scheduled it */
 extern char Ebadspec[];		/* bad attach specifier */
+extern char Enoreg[];		/* process has no saved registers */