From 319e625be0ec5d78b063308332056bed0299c2c9 Mon Sep 17 00:00:00 2001
From: Ori Bernstein <ori@eigenstate.org>
Date: Thu, 28 Jan 2021 18:07:48 -0800
Subject: [PATCH] screenlock: use initdisplay(2), top the window (thanks stuart
 morrow)

Screenlock should use libdraw(2) to init the display
and create the window, instead of looking at the screen
file directly. Also, to prevent new windows from popping
up over screenlock, bring it to the top periodically.
---
 sys/src/cmd/screenlock.c | 37 +++++++++++++++++++++++++------------
 1 file changed, 25 insertions(+), 12 deletions(-)

diff --git a/sys/src/cmd/screenlock.c b/sys/src/cmd/screenlock.c
index 8e3e48de8..9ac9fa064 100644
--- a/sys/src/cmd/screenlock.c
+++ b/sys/src/cmd/screenlock.c
@@ -17,6 +17,7 @@ usage(void)
 	exits("usage");
 }
 
+/* ^D, Delete, Enter, Backspace, ^U */
 void
 readline(char *buf, int nbuf)
 {
@@ -115,28 +116,39 @@ grabmouse(void*)
 	}
 }
 
+void
+top(void*)
+{
+	int fd;
+
+	if((fd = open("/dev/wctl", OWRITE)) < 0)
+		return;
+
+	for(;;){
+		write(fd, "current", 7);
+		sleep(500);
+	}
+}
+
 void
 lockscreen(void)
 {
-	enum { Nfld = 5, Fldlen = 12, Cursorlen = 2*4 + 2*2*16, };
+	enum { Cursorlen = 2*4 + 2*2*16 };
 	char *s;
-	char buf[Nfld*Fldlen], *flds[Nfld], newcmd[128], cbuf[Cursorlen];
+	char newcmd[128], cbuf[Cursorlen];
 	int fd, dx, dy;
 	Image *i;
 	Point p;
 	Rectangle r;
 	Tm *tm;
 
-	if((fd = open("/dev/screen", OREAD)) < 0)
-		sysfatal("can't open /dev/screen: %r");
-	if(read(fd, buf, Nfld*Fldlen) != Nfld*Fldlen)
-		sysfatal("can't read /dev/screen: %r");
-	close(fd);
-	buf[sizeof buf-1] = 0;
-	if(tokenize(buf, flds, Nfld) != Nfld)
-		sysfatal("can't tokenize /dev/screen header");
-	snprint(newcmd, sizeof newcmd, "-r %s %s %s %s",
-		flds[1], flds[2], flds[3], flds[4]);
+	display = initdisplay(nil, nil, nil);
+	if(display == nil)
+		sysfatal("can't open /dev/draw: %r");
+	r = display->image->r;
+	snprint(newcmd, sizeof newcmd, "-r %d %d %d %d",
+		r.min.x, r.min.y, r.max.x, r.max.y);
+	closedisplay(display);
 
 	newwindow(newcmd);
 	if((fd = open("/dev/consctl", OWRITE)) >= 0)
@@ -179,6 +191,7 @@ lockscreen(void)
 	flushimage(display, 1);
 
 	/* screen is now open and covered.  grab mouse and hold on tight */
+	procrfork(top, nil, 8*1024, RFFDG);
 	procrfork(grabmouse, nil, 8*1024, RFFDG);
 	procrfork(blanker, nil, 8*1024, RFFDG);