[dev] [slock] [PATCH] Add option to show the password on the screen

From: David Phillips <david_AT_sighup.nz>
Date: Sat, 1 Apr 2017 17:41:39 +1300

With slock's current behaviour, the user can become frustrated when they
suspect that they have made a typo in their password and are unable to
remember how many times to hit the backspace key to correct it. This patch
adds a configuration option for such users (I'm sure we've all been there)
so that their password is shown on the screen as they are entering it into
slock. Thusly, they can see whether they have made a mistake or typo entering
their password and can easily correct it.

---
 config.def.h |  7 +++++++
 slock.c      | 23 +++++++++++++++++++++--
 2 files changed, 28 insertions(+), 2 deletions(-)
diff --git a/config.def.h b/config.def.h
index 9855e21..f250db7 100644
--- a/config.def.h
+++ b/config.def.h
_AT_@ -2,11 +2,18 @@
 static const char *user  = "nobody";
 static const char *group = "nogroup";
 
+/* font used to display password */
+static const char *fontname = "9x15";
+
 static const char *colorname[NUMCOLS] = {
 	[INIT] =   "black",     /* after initialization */
 	[INPUT] =  "#005577",   /* during input */
 	[FAILED] = "#CC3333",   /* wrong password */
+	[TEXT] = "black",       /* password on screen */
 };
 
 /* treat a cleared input like a wrong password (color) */
 static const int failonclear = 1;
+
+/* show the password on the screen as it is typed */
+static const int showpassword = 1;
diff --git a/slock.c b/slock.c
index d55eb3d..49133fa 100644
--- a/slock.c
+++ b/slock.c
_AT_@ -23,17 +23,20 @@
 #include "util.h"
 
 char *argv0;
+XFontStruct *font;
 
 enum {
 	INIT,
 	INPUT,
 	FAILED,
+	TEXT,
 	NUMCOLS
 };
 
 struct lock {
 	int screen;
 	Window root, win;
+	GC gc;
 	Pixmap pmap;
 	unsigned long colors[NUMCOLS];
 };
_AT_@ -130,7 +133,7 @@ readpw(Display *dpy, struct xrandr *rr, struct lock **locks, int nscreens,
 {
 	XRRScreenChangeNotifyEvent *rre;
 	char buf[32], passwd[256], *inputhash;
-	int num, screen, running, failure, oldc;
+	int num, screen, running, failure, oldc, tw, dpyw, dpyh;
 	unsigned int len, color;
 	KeySym ksym;
 	XEvent ev;
_AT_@ -187,13 +190,24 @@ readpw(Display *dpy, struct xrandr *rr, struct lock **locks, int nscreens,
 				}
 				break;
 			}
+			tw = XTextWidth(font, passwd, len);
 			color = len ? INPUT : ((failure || failonclear) ? FAILED : INIT);
-			if (running && oldc != color) {
+			if (running && (showpassword || (!showpassword && oldc != color))) {
 				for (screen = 0; screen < nscreens; screen++) {
 					XSetWindowBackground(dpy,
 					                     locks[screen]->win,
 					                     locks[screen]->colors[color]);
 					XClearWindow(dpy, locks[screen]->win);
+					if (showpassword) {
+						XSetForeground(dpy, locks[screen]->gc,
+									   locks[screen]->colors[TEXT]);
+						dpyw = DisplayWidth(dpy, locks[screen]->screen);
+						dpyh = DisplayHeight(dpy, locks[screen]->screen);
+						XDrawString(dpy, locks[screen]->win,
+									locks[screen]->gc,
+									(dpyw-tw)/2, dpyh/2,
+									passwd, len);
+					}
 				}
 				oldc = color;
 			}
_AT_@ -255,6 +269,7 @@ lockscreen(Display *dpy, struct xrandr *rr, int screen)
 	invisible = XCreatePixmapCursor(dpy, lock->pmap, lock->pmap,
 	                                &color, &color, 0, 0);
 	XDefineCursor(dpy, lock->win, invisible);
+	lock->gc = XCreateGC(dpy, lock->win, 0, NULL);
 
 	/* Try to grab mouse pointer *and* keyboard for 600ms, else fail the lock */
 	for (i = 0, ptgrab = kbgrab = -1; i < 6; i++) {
_AT_@ -358,6 +373,10 @@ main(int argc, char **argv) {
 	/* check for Xrandr support */
 	rr.active = XRRQueryExtension(dpy, &rr.evbase, &rr.errbase);
 
+	/* load font ready for drawing */
+	if (NULL == (font = XLoadQueryFont(dpy, fontname)))
+		die("Failed to load font\n");
+
 	/* get number of screens in display "dpy" and blank them */
 	nscreens = ScreenCount(dpy);
 	if (!(locks = calloc(nscreens, sizeof(struct lock *))))
-- 
2.12.0

Received on Sat Apr 01 2017 - 06:41:39 CEST