Fixed bug #853
Ludwig Nussel 2009-10-18 05:34:18 PDT
src/joystick/linux/SDL_sysjoystick.c has some problems:
- test_bit() might break with strict aliasing
- test_bit() assumes array is Uint32 but its actually "unsigned long"
on 64bit systems sizeof(long) != sizeof(Uint32).
- the keybit array is too small
- the arrays are unitialized so the number of
detected buttons is quite random
--- a/src/joystick/linux/SDL_sysjoystick.c Sat Oct 17 17:35:48 2009 +0000
+++ b/src/joystick/linux/SDL_sysjoystick.c Sun Oct 18 16:14:57 2009 +0000
@@ -374,13 +374,14 @@
#if SDL_INPUT_LINUXEV
#define test_bit(nr, addr) \
- (((1UL << ((nr) & 31)) & (((const Uint32 *) addr)[(nr) >> 5])) != 0)
+ (((1UL << ((nr) % (sizeof(long) * 8))) & ((addr)[(nr) / (sizeof(long) * 8)])) != 0)
+#define NBITS(x) ((((x)-1)/(sizeof(long) * 8))+1)
static int EV_IsJoystick(int fd)
{
- unsigned long evbit[40];
- unsigned long keybit[40];
- unsigned long absbit[40];
+ unsigned long evbit[NBITS(EV_MAX)] = { 0 };
+ unsigned long keybit[NBITS(KEY_MAX)] = { 0 };
+ unsigned long absbit[NBITS(ABS_MAX)] = { 0 };
if ( (ioctl(fd, EVIOCGBIT(0, sizeof(evbit)), evbit) < 0) ||
(ioctl(fd, EVIOCGBIT(EV_KEY, sizeof(keybit)), keybit) < 0) ||
@@ -661,9 +662,9 @@
static SDL_bool EV_ConfigJoystick(SDL_Joystick *joystick, int fd)
{
int i, t;
- unsigned long keybit[40];
- unsigned long absbit[40];
- unsigned long relbit[40];
+ unsigned long keybit[NBITS(KEY_MAX)] = { 0 };
+ unsigned long absbit[NBITS(ABS_MAX)] = { 0 };
+ unsigned long relbit[NBITS(REL_MAX)] = { 0 };
/* See if this device uses the new unified event API */
if ( (ioctl(fd, EVIOCGBIT(EV_KEY, sizeof(keybit)), keybit) >= 0) &&