Presence of game pad causes segmentation fault (and proposed fix)

[jtdaugherty]

I am experiencing a segmentation fault inside of GLFW version 3.1.2. All that is required to trigger this for me is to:

• Connect one of my game pads (http://www.amazon.com/Buffalo-Classic-USB-Gamepad-PC/dp/B002B9XB0E)
• Call glfwInit()

I believe the problem is that src/cocoa_joystick.m line 280 is not checking for a possible NULL return value from IOHIDDeviceGetProperty. Then NULL is passed to CFStringGetCString which crashes. I've found reports of other applications crashing with this symptom when NULL is passed to that function. When I unplug the game pad, glfwInit() runs successfully.

I'd submit a pull request but I can't test this first since I can't get glfw3 to link on my machine.

For completeness, here is the call stack:

Process 3963 stopped
* thread #1: tid = 0x890a, 0x00007fff8b29587c CoreFoundation`CFStringGetCString + 44, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0x0)
    frame #0: 0x00007fff8b29587c CoreFoundation`CFStringGetCString + 44
CoreFoundation`CFStringGetCString:
->  0x7fff8b29587c <+44>: movq   (%r12), %rax
    0x7fff8b295880 <+48>: testq  %rax, %rax
    0x7fff8b295883 <+51>: je     0x7fff8b2958c4            ; <+116>
    0x7fff8b295885 <+53>: leaq   -0x13d4bba4(%rip), %rcx   ; __CFConstantStringClassReferencePtr
(lldb) bt
* thread #1: tid = 0x890a, 0x00007fff8b29587c CoreFoundation`CFStringGetCString + 44, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0x0)
  * frame #0: 0x00007fff8b29587c CoreFoundation`CFStringGetCString + 44
    frame #1: 0x0000000100011f86 libglfw3.3.dylib`matchCallback + 148
    frame #2: 0x00007fff8a848c21 IOKit`__IOHIDManagerDeviceApplier + 153
    frame #3: 0x00007fff8b2c0372 CoreFoundation`__CFSetApplyFunction_block_invoke + 18
    frame #4: 0x00007fff8b2a4f80 CoreFoundation`CFBasicHashApply + 128
    frame #5: 0x00007fff8b2c030a CoreFoundation`CFSetApplyFunction + 186
    frame #6: 0x00007fff8a849e86 IOKit`__IOHIDManagerInitialEnumCallback + 58
    frame #7: 0x00007fff8b2e15c1 CoreFoundation`__CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 17
    frame #8: 0x00007fff8b2d341c CoreFoundation`__CFRunLoopDoSources0 + 556
    frame #9: 0x00007fff8b2d293f CoreFoundation`__CFRunLoopRun + 927
    frame #10: 0x00007fff8b2d2338 CoreFoundation`CFRunLoopRunSpecific + 296
    frame #11: 0x000000010000e63d libglfw3.3.dylib`_glfwPlatformInit + 1287
    frame #12: 0x000000010000bcf2 libglfw3.3.dylib`glfwInit + 42
    frame #13: 0x0000000100002268 t2`main + 2776
    frame #14: 0x00007fff92d2b5ad libdyld.dylib`start + 1

[elmindreda]

This should be fixed by #701.

[jtdaugherty]

Thank you!