error messages on grab failure

1 files changed, 16 insertions, 14 deletions

diff --git a/slock.c b/slock.c
index d2c3729..df2d3c6 100644
--- a/slock.c
+++ b/slock.c
@@ -230,7 +230,7 @@ lockscreen(Display *dpy, int screen)
         XSetWindowAttributes wa;
         Cursor invisible;
 
-        if (dpy == NULL || screen < 0 || !(lock = malloc(sizeof(Lock))))
+        if (!running || dpy == NULL || screen < 0 || !(lock = malloc(sizeof(Lock))))
                 return NULL;
 
         lock->screen = screen;
@@ -253,29 +253,31 @@ lockscreen(Display *dpy, int screen)
         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 (running && len) {
+        if (!len) {
+                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)
-                                break;
+                        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);
                 }
+                fprintf(stderr, "slock: unable to grab keyboard for screen %d\n", screen);
         }
-
-        running &= (len > 0);
-        if (!running) {
-                unlockscreen(dpy, lock);
-                lock = NULL;
-        } else {
-                XSelectInput(dpy, lock->root, SubstructureNotifyMask);
-        }
-
-        return lock;
+        /* grabbing one of the inputs failed */
+        running = 0;
+        unlockscreen(dpy, lock);
+        return NULL;
 }
 
 static void