diff -Nru /n/sources/plan9/sys/src/libdraw/event.c /sys/src/libdraw/event.c
--- /n/sources/plan9/sys/src/libdraw/event.c	Fri May  9 22:00:25 2008
+++ /sys/src/libdraw/event.c	Sun Nov  6 00:00:00 2016
@@ -434,7 +434,7 @@
 	char buf[2*12+2];
 	int n;
 
-	n = sprint(buf, "m%d %d", pt.x, pt.y);
+	n = snprint(buf, sizeof buf, "m%d %d", pt.x, pt.y);
 	write(mousefd, buf, n);
 }
 
diff -Nru /n/sources/plan9/sys/src/libdraw/init.c /sys/src/libdraw/init.c
--- /n/sources/plan9/sys/src/libdraw/init.c	Fri Jan 25 18:36:15 2013
+++ /sys/src/libdraw/init.c	Sun Nov  6 00:00:00 2016
@@ -220,7 +220,7 @@
 	if(t == nil)
 		return nil;
 
-	sprint(buf, "%s/draw/new", dev);
+	snprint(buf, sizeof buf, "%s/draw/new", dev);
 	ctlfd = open(buf, ORDWR|OCEXEC);
 	if(ctlfd < 0){
 		if(bind("#i", dev, MAFTER) < 0){
@@ -244,11 +244,11 @@
 	isnew = 0;
 	if(n < NINFO)	/* this will do for now, we need something better here */
 		isnew = 1;
-	sprint(buf, "%s/draw/%d/data", dev, atoi(info+0*12));
+	snprint(buf, sizeof buf, "%s/draw/%d/data", dev, atoi(info+0*12));
 	datafd = open(buf, ORDWR|OCEXEC);
 	if(datafd < 0)
 		goto Error2;
-	sprint(buf, "%s/draw/%d/refresh", dev, atoi(info+0*12));
+	snprint(buf, sizeof buf, "%s/draw/%d/refresh", dev, atoi(info+0*12));
 	reffd = open(buf, OREAD|OCEXEC);
 	if(reffd < 0){
     Error3:
diff -Nru /n/sources/plan9/sys/src/libdraw/keyboard.c /sys/src/libdraw/keyboard.c
--- /n/sources/plan9/sys/src/libdraw/keyboard.c	Mon Sep  2 12:34:51 2002
+++ /sys/src/libdraw/keyboard.c	Sun Nov  6 00:00:00 2016
@@ -59,6 +59,7 @@
 Keyboardctl*
 initkeyboard(char *file)
 {
+	int nb;
 	Keyboardctl *kc;
 	char *t;
 
@@ -69,13 +70,14 @@
 		file = "/dev/cons";
 	kc->file = strdup(file);
 	kc->consfd = open(file, ORDWR|OCEXEC);
-	t = malloc(strlen(file)+16);
+	nb = strlen(file)+16;
+	t = malloc(nb);
 	if(kc->consfd<0 || t==nil){
 Error1:
 		free(kc);
 		return nil;
 	}
-	sprint(t, "%sctl", file);
+	snprint(t, nb, "%sctl", file);
 	kc->ctlfd = open(t, OWRITE|OCEXEC);
 	if(kc->ctlfd < 0){
 		fprint(2, "initkeyboard: can't open %s: %r\n", t);
diff -Nru /n/sources/plan9/sys/src/libdraw/readcolmap.c /sys/src/libdraw/readcolmap.c
--- /n/sources/plan9/sys/src/libdraw/readcolmap.c	Thu Feb 28 20:24:37 2002
+++ /sys/src/libdraw/readcolmap.c	Sun Nov  6 00:00:00 2016
@@ -26,7 +26,7 @@
 
 	USED(screen);
 
-	sprint(buf, "/dev/draw/%d/colormap", d->dirno);
+	snprint(buf, sizeof buf, "/dev/draw/%d/colormap", d->dirno);
 	b = Bopen(buf, OREAD);
 	if(b == 0)
 		drawerror(d, "rdcolmap: can't open colormap device");
diff -Nru /n/sources/plan9/sys/src/libdraw/writecolmap.c /sys/src/libdraw/writecolmap.c
--- /n/sources/plan9/sys/src/libdraw/writecolmap.c	Fri Apr 13 22:11:10 2007
+++ /sys/src/libdraw/writecolmap.c	Sun Nov  6 00:00:00 2016
@@ -15,7 +15,7 @@
 	char buf[64], *t;
 	ulong r, g, b;
 
-	sprint(buf, "/dev/draw/%d/colormap", d->dirno);
+	snprint(buf, sizeof buf, "/dev/draw/%d/colormap", d->dirno);
 	fd = open(buf, OWRITE);
 	if(fd < 0)
 		drawerror(d, "writecolmap: open colormap failed");
diff -Nru /n/sources/plan9/sys/src/libdraw/writeimage.c /sys/src/libdraw/writeimage.c
--- /n/sources/plan9/sys/src/libdraw/writeimage.c	Thu Feb 28 20:24:37 2002
+++ /sys/src/libdraw/writeimage.c	Sun Nov  6 00:00:00 2016
@@ -66,7 +66,7 @@
 		if(nb != dy*bpl)
 			goto ErrOut;
 	}
-	sprint(hdr, "compressed\n%11s %11d %11d %11d %11d ",
+	snprint(hdr, sizeof hdr, "compressed\n%11s %11d %11d %11d %11d ",
 		chantostr(cbuf, i->chan), r.min.x, r.min.y, r.max.x, r.max.y);
 	if(write(fd, hdr, 11+5*12) != 11+5*12)
 		goto ErrOut;
@@ -172,7 +172,7 @@
 		if(loutp == outbuf)
 			goto ErrOut;
 		n = loutp-outbuf;
-		sprint(hdr, "%11d %11ld ", r.max.y, n);
+		snprint(hdr, sizeof hdr, "%11d %11ld ", r.max.y, n);
 		write(fd, hdr, 2*12);
 		write(fd, outbuf, n);
 		r.min.y = r.max.y;
diff -Nru /n/sources/plan9/sys/src/libdraw/writesubfont.c /sys/src/libdraw/writesubfont.c
--- /n/sources/plan9/sys/src/libdraw/writesubfont.c	Sun Dec 12 01:22:05 1999
+++ /sys/src/libdraw/writesubfont.c	Sun Nov  6 00:00:00 2016
@@ -27,7 +27,7 @@
 	uchar *data;
 	int nb;
 
-	sprint(hdr, "%11d %11d %11d ", f->n, f->height, f->ascent);
+	snprint(hdr, sizeof hdr, "%11d %11d %11d ", f->n, f->height, f->ascent);
 	if(write(fd, hdr, 3*12) != 3*12){
    Err:
 		werrstr("writesubfont: bad write: %r");