+#define OLD_KEY_MAX 0x1ff
+static int handle_eviocgbit(struct input_dev *dev, unsigned int cmd, void __user *p, int compat_mode)
+{
+ static unsigned long keymax_warn_time;
+ unsigned long *bits;
+ int len;
+
+ switch (_IOC_NR(cmd) & EV_MAX) {
+
+ case 0: bits = dev->evbit; len = EV_MAX; break;
+ case EV_KEY: bits = dev->keybit; len = KEY_MAX; break;
+ case EV_REL: bits = dev->relbit; len = REL_MAX; break;
+ case EV_ABS: bits = dev->absbit; len = ABS_MAX; break;
+ case EV_MSC: bits = dev->mscbit; len = MSC_MAX; break;
+ case EV_LED: bits = dev->ledbit; len = LED_MAX; break;
+ case EV_SND: bits = dev->sndbit; len = SND_MAX; break;
+ case EV_FF: bits = dev->ffbit; len = FF_MAX; break;
+ case EV_SW: bits = dev->swbit; len = SW_MAX; break;
+ default: return -EINVAL;
+ }
+
+ /*
+ * Work around bugs in userspace programs that like to do
+ * EVIOCGBIT(EV_KEY, KEY_MAX) and not realize that 'len'
+ * should be in bytes, not in bits.
+ */
+ if ((_IOC_NR(cmd) & EV_MAX) == EV_KEY && _IOC_SIZE(cmd) == OLD_KEY_MAX) {
+ len = OLD_KEY_MAX;
+ if (printk_timed_ratelimit(&keymax_warn_time, 10 * 1000))
+ printk(KERN_WARNING
+ "evdev.c(EVIOCGBIT): Suspicious buffer size %u, "
+ "limiting output to %zu bytes. See "
+ "http://userweb.kernel.org/~dtor/eviocgbit-bug.html\n",
+ OLD_KEY_MAX,
+ BITS_TO_LONGS(OLD_KEY_MAX) * sizeof(long));
+ }
+
+ return bits_to_user(bits, len, _IOC_SIZE(cmd), p, compat_mode);
+}
+#undef OLD_KEY_MAX
+