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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
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slouken committed Oct 18, 2009
1 parent 61fb281 commit 5873d7712a6083309aafbb1357102ed336ec2688
Showing with 8 additions and 7 deletions.
  1. +8 −7 src/joystick/linux/SDL_sysjoystick.c
@@ -374,13 +374,14 @@ static void LogicalSuffix(int logicalno, char* namebuf, int len)

#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 JS_ConfigJoystick(SDL_Joystick *joystick, int fd)
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) &&

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