Exit as soon as possible on input grabbing error

We want to know at once if slock failed or not to lock the screen, not
seing a black screen for a whole second (or two) and then die.
Thanks to ^7heo for reporting this.

diff --git a/slock.c b/slock.c
index 210d5c8..dd32374 100644 (file)
--- a/slock.c
+++ b/slock.c
@@ -222,7 +222,6 @@ static Lock *
 lockscreen(Display *dpy, int screen)
 {
        char curs[] = {0, 0, 0, 0, 0, 0, 0, 0};
-       unsigned int len;
        int i;
        Lock *lock;
        XColor color, dummy;
@@ -249,34 +248,31 @@ lockscreen(Display *dpy, int screen)
        lock->pmap = XCreateBitmapFromData(dpy, lock->win, curs, 8, 8);
        invisible = XCreatePixmapCursor(dpy, lock->pmap, lock->pmap, &color, &color, 0, 0);
        XDefineCursor(dpy, lock->win, invisible);
-       XMapRaised(dpy, lock->win);
-       if (rr)
-               XRRSelectInput(dpy, lock->win, RRScreenChangeNotifyMask);
 
        /* Try to grab mouse pointer *and* keyboard, else fail the lock */
-       for (len = 1000; len; len--) {
-               if (XGrabPointer(dpy, lock->root, False, ButtonPressMask | ButtonReleaseMask | PointerMotionMask,
-                   GrabModeAsync, GrabModeAsync, None, invisible, CurrentTime) == GrabSuccess)
-                       break;
-               usleep(1000);
-       }
-       if (!len) {
+       if (XGrabPointer(dpy, lock->root, False, ButtonPressMask |
+           ButtonReleaseMask | PointerMotionMask, GrabModeAsync, GrabModeAsync,
+           None, invisible, CurrentTime) != GrabSuccess) {
                fprintf(stderr, "slock: unable to grab mouse pointer for screen %d\n", screen);
-       } else {
-               for (len = 1000; len; len--) {
-                       if (XGrabKeyboard(dpy, lock->root, True, GrabModeAsync, GrabModeAsync, CurrentTime) == GrabSuccess) {
-                               /* everything fine, we grabbed both inputs */
-                               XSelectInput(dpy, lock->root, SubstructureNotifyMask);
-                               return lock;
-                       }
-                       usleep(1000);
-               }
+               running = 0;
+               unlockscreen(dpy, lock);
+               return NULL;
+       }
+
+       if (XGrabKeyboard(dpy, lock->root, True, GrabModeAsync, GrabModeAsync,
+           CurrentTime) != GrabSuccess) {
                fprintf(stderr, "slock: unable to grab keyboard for screen %d\n", screen);
+               running = 0;
+               unlockscreen(dpy, lock);
+               return NULL;
        }
-       /* grabbing one of the inputs failed */
-       running = 0;
-       unlockscreen(dpy, lock);
-       return NULL;
+
+       XMapRaised(dpy, lock->win);
+       if (rr)
+               XRRSelectInput(dpy, lock->win, RRScreenChangeNotifyMask);
+
+       XSelectInput(dpy, lock->root, SubstructureNotifyMask);
+       return lock;
 }
 
 static void