From 8a18f80a372874da930e0ec22c4c6865a0268eb0 Mon Sep 17 00:00:00 2001
From: "Dmitry V. Levin" <ldv@altlinux.org>
Date: Fri, 27 May 2016 00:40:10 +0000
Subject: [PATCH] evdev.c: reorder ioctl command checks

Change the order of ioctl command cheks to match the kernel:
1st, check for fixed-number fixed-length commands,
2nd, check for fixed-number variable-length commands,
3rd, check for multi-number fixed-length commands,
4thm check for multi-number variable-length commands.

* evdev.c (evdev_read_ioctl, evdev_write_ioctl): Reorder
ioctl command checks.
---
 evdev.c | 120 +++++++++++++++++++++++++++++---------------------------
 1 file changed, 63 insertions(+), 57 deletions(-)

diff --git a/evdev.c b/evdev.c
index dd068a86..dda8f54e 100644
--- a/evdev.c
+++ b/evdev.c
@@ -308,59 +308,12 @@ repeat_ioctl(struct tcb *tcp, long arg)
 # endif /* EVIOCGREP || EVIOCSREP */
 
 static int
-evdev_read_ioctl(struct tcb *tcp, const unsigned int code, long arg)
+evdev_read_ioctl(struct tcb *tcp, const unsigned int code, const long arg)
 {
 	if (syserror(tcp))
 		return 0;
 
-	if ((_IOC_NR(code) & ~EV_MAX) == _IOC_NR(EVIOCGBIT(0, 0))) {
-		switch (_IOC_NR(code) - 0x20) {
-			case EV_SYN:
-				return decode_bitset(tcp, arg, evdev_sync,
-						SYN_MAX, "SYN_???");
-			case EV_KEY:
-				return decode_bitset(tcp, arg, evdev_keycode,
-						KEY_MAX, "KEY_???");
-			case EV_REL:
-				return decode_bitset(tcp, arg, evdev_relative_axes,
-						REL_MAX, "REL_???");
-			case EV_ABS:
-				return decode_bitset(tcp, arg,
-						evdev_abs, ABS_MAX, "ABS_???");
-			case EV_MSC:
-				return decode_bitset(tcp, arg,
-						evdev_misc, MSC_MAX, "MSC_???");
-# ifdef EV_SW
-			case EV_SW:
-				return decode_bitset(tcp, arg,
-						evdev_switch, SW_MAX, "SW_???");
-# endif
-			case EV_LED:
-				return decode_bitset(tcp, arg,
-						evdev_leds, LED_MAX, "LED_???");
-			case EV_SND:
-				return decode_bitset(tcp, arg,
-						evdev_snd, SND_MAX, "SND_???");
-			case EV_REP:
-				return decode_bitset(tcp, arg, evdev_autorepeat,
-						REP_MAX, "REP_???");
-			case EV_FF:
-				return decode_bitset(tcp, arg, evdev_ff_types,
-						FF_MAX, "FF_???");
-			case EV_PWR:
-				printnum_int(tcp, arg, "%d");
-				return 1;
-			case EV_FF_STATUS:
-				return decode_bitset(tcp, arg, evdev_ff_status,
-						FF_STATUS_MAX, "FF_STATUS_???");
-			default:
-				return 0;
-		}
-	}
-
-	if ((_IOC_NR(code) & ~ABS_MAX) == _IOC_NR(EVIOCGABS(0)))
-		return abs_ioctl(tcp, arg);
-
+	/* fixed-number fixed-length commands */
 	switch (code) {
 		case EVIOCGVERSION:
 			tprints(", ");
@@ -384,6 +337,7 @@ evdev_read_ioctl(struct tcb *tcp, const unsigned int code, long arg)
 # endif
 	}
 
+	/* fixed-number variable-length commands */
 	switch (_IOC_NR(code)) {
 # ifdef EVIOCGMTSLOTS
 		case _IOC_NR(EVIOCGMTSLOTS(0)):
@@ -414,17 +368,65 @@ evdev_read_ioctl(struct tcb *tcp, const unsigned int code, long arg)
 		case _IOC_NR(EVIOCGLED(0)):
 			return decode_bitset(tcp, arg,
 					evdev_leds, LED_MAX, "LED_???");
-		default:
-			return 0;
 	}
+
+	/* multi-number fixed-length commands */
+	if ((_IOC_NR(code) & ~ABS_MAX) == _IOC_NR(EVIOCGABS(0)))
+		return abs_ioctl(tcp, arg);
+
+	/* multi-number variable-length commands */
+	if ((_IOC_NR(code) & ~EV_MAX) == _IOC_NR(EVIOCGBIT(0, 0))) {
+		switch (_IOC_NR(code) - 0x20) {
+			case EV_SYN:
+				return decode_bitset(tcp, arg, evdev_sync,
+						SYN_MAX, "SYN_???");
+			case EV_KEY:
+				return decode_bitset(tcp, arg, evdev_keycode,
+						KEY_MAX, "KEY_???");
+			case EV_REL:
+				return decode_bitset(tcp, arg, evdev_relative_axes,
+						REL_MAX, "REL_???");
+			case EV_ABS:
+				return decode_bitset(tcp, arg,
+						evdev_abs, ABS_MAX, "ABS_???");
+			case EV_MSC:
+				return decode_bitset(tcp, arg,
+						evdev_misc, MSC_MAX, "MSC_???");
+# ifdef EV_SW
+			case EV_SW:
+				return decode_bitset(tcp, arg,
+						evdev_switch, SW_MAX, "SW_???");
+# endif
+			case EV_LED:
+				return decode_bitset(tcp, arg,
+						evdev_leds, LED_MAX, "LED_???");
+			case EV_SND:
+				return decode_bitset(tcp, arg,
+						evdev_snd, SND_MAX, "SND_???");
+			case EV_REP:
+				return decode_bitset(tcp, arg, evdev_autorepeat,
+						REP_MAX, "REP_???");
+			case EV_FF:
+				return decode_bitset(tcp, arg, evdev_ff_types,
+						FF_MAX, "FF_???");
+			case EV_PWR:
+				printnum_int(tcp, arg, "%d");
+				return 1;
+			case EV_FF_STATUS:
+				return decode_bitset(tcp, arg, evdev_ff_status,
+						FF_STATUS_MAX, "FF_STATUS_???");
+			default:
+				return 0;
+		}
+	}
+
+	return 0;
 }
 
 static int
-evdev_write_ioctl(struct tcb *tcp, const unsigned int code, long arg)
+evdev_write_ioctl(struct tcb *tcp, const unsigned int code, const long arg)
 {
-	if ((_IOC_NR(code) & ~ABS_MAX) == _IOC_NR(EVIOCSABS(0)))
-		return abs_ioctl(tcp, arg);
-
+	/* fixed-number fixed-length commands */
 	switch (code) {
 # ifdef EVIOCSREP
 		case EVIOCSREP:
@@ -449,9 +451,13 @@ evdev_write_ioctl(struct tcb *tcp, const unsigned int code, long arg)
 			tprints(", ");
 			printnum_int(tcp, arg, "%u");
 			return 1;
-		default:
-			return 0;
 	}
+
+	/* multi-number fixed-length commands */
+	if ((_IOC_NR(code) & ~ABS_MAX) == _IOC_NR(EVIOCSABS(0)))
+		return abs_ioctl(tcp, arg);
+
+	return 0;
 }
 
 int
-- 
2.50.1