From 16784a2e45937c6d4df5fe21c0838f8a7dfeb0a7 Mon Sep 17 00:00:00 2001
From: cinap_lenrek <cinap_lenrek@felloff.net>
Date: Sun, 12 Jan 2020 00:07:27 +0100
Subject: devdraw: fix topnwindows() panic when images are not windows (thanks
 aiju)

Crashes drawterm and native:

#include <u.h>
#include <libc.h>
#include <draw.h>

void
main(int argc, char **argv)
{
 	initdraw(nil, nil, nil);

 	Image *a[] = {screen, display->black};

 	topnwindows(a, nelem(a));
 	flushimage(display, 1);
}
---
 sys/src/9/port/devdraw.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/sys/src/9/port/devdraw.c b/sys/src/9/port/devdraw.c
index c9b8be2e3..259d6ddf3 100644
--- a/sys/src/9/port/devdraw.c
+++ b/sys/src/9/port/devdraw.c
@@ -2022,13 +2022,13 @@ drawmesg(Client *client, void *av, int n)
 				free(lp);
 				nexterror();
 			}
-			for(j=0; j<nw; j++)
+			for(j=0; j<nw; j++){
 				lp[j] = drawimage(client, a+1+1+2+j*4);
-			if(lp[0]->layer == 0)
-				error("images are not windows");
-			for(j=1; j<nw; j++)
+				if(lp[j]->layer == 0)
+					error("images are not windows");
 				if(lp[j]->layer->screen != lp[0]->layer->screen)
 					error("images not on same screen");
+			}
 			if(a[1])
 				memltofrontn(lp, nw);
 			else
-- 
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