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Uses SDL_UDEV for Linux joystick hotplugging
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@gabomdq
gabomdq committed Oct 1, 2013
1 parent 69a4351 commit 57e0931
Showing 1 changed file with 81 additions and 244 deletions.
325 changes: 81 additions & 244 deletions src/joystick/linux/SDL_sysjoystick.c
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Expand Up @@ -52,124 +52,13 @@
#define SYN_DROPPED 3
#endif

/*
* !!! FIXME: move all the udev stuff to src/core/linux, so I can reuse it
* !!! FIXME: for audio hardware disconnects.
*/
#ifdef HAVE_LIBUDEV_H
#define SDL_USE_LIBUDEV 1
#include "SDL_loadso.h"
#include <libudev.h>
#include <sys/time.h>
#include <sys/types.h>

/* we never link directly to libudev. */
/* !!! FIXME: can we generalize this? ALSA, etc, do the same things. */
static const char *udev_library = "libudev.so.0";
static void *udev_handle = NULL;

/* !!! FIXME: this is kinda ugly. */
static SDL_bool
load_udev_sym(const char *fn, void **addr)
{
*addr = SDL_LoadFunction(udev_handle, fn);
if (*addr == NULL) {
/* Don't call SDL_SetError(): SDL_LoadFunction already did. */
return SDL_FALSE;
}

return SDL_TRUE;
}

/* libudev entry points... */
static const char *(*UDEV_udev_device_get_action)(struct udev_device *) = NULL;
static const char *(*UDEV_udev_device_get_devnode)(struct udev_device *) = NULL;
static const char *(*UDEV_udev_device_get_property_value)(struct udev_device *, const char *) = NULL;
static struct udev_device *(*UDEV_udev_device_new_from_syspath)(struct udev *, const char *) = NULL;
static void (*UDEV_udev_device_unref)(struct udev_device *) = NULL;
static int (*UDEV_udev_enumerate_add_match_property)(struct udev_enumerate *, const char *, const char *) = NULL;
static int (*UDEV_udev_enumerate_add_match_subsystem)(struct udev_enumerate *, const char *) = NULL;
static struct udev_list_entry *(*UDEV_udev_enumerate_get_list_entry)(struct udev_enumerate *) = NULL;
static struct udev_enumerate *(*UDEV_udev_enumerate_new)(struct udev *) = NULL;
static int (*UDEV_udev_enumerate_scan_devices)(struct udev_enumerate *) = NULL;
static void (*UDEV_udev_enumerate_unref)(struct udev_enumerate *) = NULL;
static const char *(*UDEV_udev_list_entry_get_name)(struct udev_list_entry *) = NULL;
static struct udev_list_entry *(*UDEV_udev_list_entry_get_next)(struct udev_list_entry *) = NULL;
static int (*UDEV_udev_monitor_enable_receiving)(struct udev_monitor *) = NULL;
static int (*UDEV_udev_monitor_filter_add_match_subsystem_devtype)(struct udev_monitor *, const char *, const char *) = NULL;
static int (*UDEV_udev_monitor_get_fd)(struct udev_monitor *) = NULL;
static struct udev_monitor *(*UDEV_udev_monitor_new_from_netlink)(struct udev *, const char *) = NULL;
static struct udev_device *(*UDEV_udev_monitor_receive_device)(struct udev_monitor *) = NULL;
static void (*UDEV_udev_monitor_unref)(struct udev_monitor *) = NULL;
static struct udev *(*UDEV_udev_new)(void) = NULL;
static void (*UDEV_udev_unref)(struct udev *) = NULL;
#include "../../core/linux/SDL_udev.h"

static int
load_udev_syms(void)
{
/* cast funcs to char* first, to please GCC's strict aliasing rules. */
#define SDL_UDEV_SYM(x) \
if (!load_udev_sym(#x, (void **) (char *) &UDEV_##x)) return -1

SDL_UDEV_SYM(udev_device_get_action);
SDL_UDEV_SYM(udev_device_get_devnode);
SDL_UDEV_SYM(udev_device_get_property_value);
SDL_UDEV_SYM(udev_device_new_from_syspath);
SDL_UDEV_SYM(udev_device_unref);
SDL_UDEV_SYM(udev_enumerate_add_match_property);
SDL_UDEV_SYM(udev_enumerate_add_match_subsystem);
SDL_UDEV_SYM(udev_enumerate_get_list_entry);
SDL_UDEV_SYM(udev_enumerate_new);
SDL_UDEV_SYM(udev_enumerate_scan_devices);
SDL_UDEV_SYM(udev_enumerate_unref);
SDL_UDEV_SYM(udev_list_entry_get_name);
SDL_UDEV_SYM(udev_list_entry_get_next);
SDL_UDEV_SYM(udev_monitor_enable_receiving);
SDL_UDEV_SYM(udev_monitor_filter_add_match_subsystem_devtype);
SDL_UDEV_SYM(udev_monitor_get_fd);
SDL_UDEV_SYM(udev_monitor_new_from_netlink);
SDL_UDEV_SYM(udev_monitor_receive_device);
SDL_UDEV_SYM(udev_monitor_unref);
SDL_UDEV_SYM(udev_new);
SDL_UDEV_SYM(udev_unref);

#undef SDL_UDEV_SYM

return 0;
}

static void
UnloadUDEVLibrary(void)
{
if (udev_handle != NULL) {
SDL_UnloadObject(udev_handle);
udev_handle = NULL;
}
}

static int
LoadUDEVLibrary(void)
{
int retval = 0;
if (udev_handle == NULL) {
udev_handle = SDL_LoadObject(udev_library);
if (udev_handle == NULL) {
retval = -1;
/* Don't call SDL_SetError(): SDL_LoadObject already did. */
} else {
retval = load_udev_syms();
if (retval < 0) {
UnloadUDEVLibrary();
}
}
}

return retval;
}

static struct udev *udev = NULL;
static struct udev_monitor *udev_mon = NULL;
#endif
static int MaybeAddDevice(const char *path);
#if SDL_USE_LIBUDEV
static int MaybeRemoveDevice(const char *path);
void joystick_udev_callback(SDL_UDEV_deviceevent udev_type, SDL_UDEV_deviceclass udev_class, const char *devpath);
#endif /* SDL_USE_LIBUDEV */


/* A linked list of available joysticks */
Expand Down Expand Up @@ -246,6 +135,62 @@ IsJoystick(int fd, char *namebuf, const size_t namebuflen, SDL_JoystickGUID *gui
return 1;
}

#if SDL_USE_LIBUDEV
void joystick_udev_callback(SDL_UDEV_deviceevent udev_type, SDL_UDEV_deviceclass udev_class, const char *devpath)
{
int instance;

if (devpath == NULL || udev_class != SDL_UDEV_DEVICE_JOYSTICK) {
return;
}

switch( udev_type )
{
case SDL_UDEV_DEVICEADDED:
instance = MaybeAddDevice(devpath);
if (instance != -1) {
/* !!! FIXME: Move this to an SDL_PrivateJoyDeviceAdded() function? */
#if !SDL_EVENTS_DISABLED
SDL_Event event;
event.type = SDL_JOYDEVICEADDED;

if (SDL_GetEventState(event.type) == SDL_ENABLE) {
event.jdevice.which = instance;
if ( (SDL_EventOK == NULL) ||
(*SDL_EventOK) (SDL_EventOKParam, &event) ) {
SDL_PushEvent(&event);
}
}
#endif /* !SDL_EVENTS_DISABLED */
}
break;

case SDL_UDEV_DEVICEREMOVED:
instance = MaybeRemoveDevice(devpath);
if (instance != -1) {
/* !!! FIXME: Move this to an SDL_PrivateJoyDeviceRemoved() function? */
#if !SDL_EVENTS_DISABLED
SDL_Event event;
event.type = SDL_JOYDEVICEREMOVED;

if (SDL_GetEventState(event.type) == SDL_ENABLE) {
event.jdevice.which = instance;
if ( (SDL_EventOK == NULL) ||
(*SDL_EventOK) (SDL_EventOKParam, &event) ) {
SDL_PushEvent(&event);
}
}
#endif /* !SDL_EVENTS_DISABLED */
}
break;

default:
break;
}

}
#endif /* SDL_USE_LIBUDEV */


/* !!! FIXME: I would love to dump this code and use libudev instead. */
static int
Expand Down Expand Up @@ -380,40 +325,19 @@ JoystickInitWithoutUdev(void)
static int
JoystickInitWithUdev(void)
{
struct udev_enumerate *enumerate = NULL;
struct udev_list_entry *devs = NULL;
struct udev_list_entry *item = NULL;

SDL_assert(udev == NULL);
udev = UDEV_udev_new();
if (udev == NULL) {
return SDL_SetError("udev_new() failed");
}

udev_mon = UDEV_udev_monitor_new_from_netlink(udev, "udev");
if (udev_mon != NULL) { /* okay if it's NULL, we just lose hotplugging. */
UDEV_udev_monitor_filter_add_match_subsystem_devtype(udev_mon,
"input", NULL);
UDEV_udev_monitor_enable_receiving(udev_mon);
}

enumerate = UDEV_udev_enumerate_new(udev);
if (enumerate == NULL) {
return SDL_SetError("udev_enumerate_new() failed");
if (SDL_UDEV_Init() < 0) {
return SDL_SetError("Could not initialize UDEV");
}

UDEV_udev_enumerate_add_match_subsystem(enumerate, "input");
UDEV_udev_enumerate_add_match_property(enumerate, "ID_INPUT_JOYSTICK", "1");
UDEV_udev_enumerate_scan_devices(enumerate);
devs = UDEV_udev_enumerate_get_list_entry(enumerate);
for (item = devs; item; item = UDEV_udev_list_entry_get_next(item)) {
const char *path = UDEV_udev_list_entry_get_name(item);
struct udev_device *dev = UDEV_udev_device_new_from_syspath(udev, path);
MaybeAddDevice(UDEV_udev_device_get_devnode(dev));
UDEV_udev_device_unref(dev);
/* Set up the udev callback */
if ( SDL_UDEV_AddCallback(joystick_udev_callback) < 0) {
SDL_UDEV_Quit();
return SDL_SetError("Could not set up joystick <-> udev callback");
}

UDEV_udev_enumerate_unref(enumerate);

/* Force a scan to build the initial device list */
SDL_UDEV_Scan();

return numjoysticks;
}
Expand All @@ -439,9 +363,7 @@ SDL_SYS_JoystickInit(void)
}

#if SDL_USE_LIBUDEV
if (LoadUDEVLibrary() == 0) { /* okay if this fails, FOR NOW. */
return JoystickInitWithUdev();
}
return JoystickInitWithUdev();
#endif

return JoystickInitWithoutUdev();
Expand All @@ -452,99 +374,21 @@ int SDL_SYS_NumJoysticks()
return numjoysticks;
}

static SDL_bool
HotplugUpdateAvailable(void)
{
#if SDL_USE_LIBUDEV
if (udev_mon != NULL) {
const int fd = UDEV_udev_monitor_get_fd(udev_mon);
fd_set fds;
struct timeval tv;

FD_ZERO(&fds);
FD_SET(fd, &fds);
tv.tv_sec = 0;
tv.tv_usec = 0;
if ((select(fd+1, &fds, NULL, NULL, &tv) > 0) && (FD_ISSET(fd, &fds))) {
return SDL_TRUE;
}
}
#endif

return SDL_FALSE;
}

void SDL_SYS_JoystickDetect()
{
#if SDL_USE_LIBUDEV
struct udev_device *dev = NULL;
const char *devnode = NULL;
const char *action = NULL;
const char *val = NULL;

while (HotplugUpdateAvailable()) {
dev = UDEV_udev_monitor_receive_device(udev_mon);
if (dev == NULL) {
break;
}
val = UDEV_udev_device_get_property_value(dev, "ID_INPUT_JOYSTICK");
if ((!val) || (SDL_strcmp(val, "1") != 0)) {
continue;
}

action = UDEV_udev_device_get_action(dev);
devnode = UDEV_udev_device_get_devnode(dev);

if (SDL_strcmp(action, "add") == 0) {
const int device_index = MaybeAddDevice(devnode);
if (device_index != -1) {
/* !!! FIXME: Move this to an SDL_PrivateJoyDeviceAdded() function? */
#if !SDL_EVENTS_DISABLED
SDL_Event event;
event.type = SDL_JOYDEVICEADDED;

if (SDL_GetEventState(event.type) == SDL_ENABLE) {
event.jdevice.which = device_index;
if ( (SDL_EventOK == NULL) ||
(*SDL_EventOK) (SDL_EventOKParam, &event) ) {
SDL_PushEvent(&event);
}
}
#endif /* !SDL_EVENTS_DISABLED */
}
} else if (SDL_strcmp(action, "remove") == 0) {
const int inst = MaybeRemoveDevice(devnode);
if (inst != -1) {
/* !!! FIXME: Move this to an SDL_PrivateJoyDeviceRemoved() function? */
#if !SDL_EVENTS_DISABLED
SDL_Event event;
event.type = SDL_JOYDEVICEREMOVED;

if (SDL_GetEventState(event.type) == SDL_ENABLE) {
event.jdevice.which = inst;
if ( (SDL_EventOK == NULL) ||
(*SDL_EventOK) (SDL_EventOKParam, &event) ) {
SDL_PushEvent(&event);
}
}
#endif /* !SDL_EVENTS_DISABLED */
}
}
UDEV_udev_device_unref(dev);
}
SDL_UDEV_Poll();
#endif

}

SDL_bool SDL_SYS_JoystickNeedsPolling()
{
/*
* This results in a select() call, so technically we're polling to
* decide if we should poll, but I think this function is here because
* Windows has to do an enormous amount of work to detect new sticks,
* whereas libudev just needs to see if there's more data available on
* a socket...so this should be acceptable, I hope.
*/
return HotplugUpdateAvailable();
#if SDL_USE_LIBUDEV
return SDL_TRUE;
#endif

return SDL_FALSE;
}

static SDL_joylist_item *
Expand Down Expand Up @@ -1011,15 +855,8 @@ SDL_SYS_JoystickQuit(void)
instance_counter = 0;

#if SDL_USE_LIBUDEV
if (udev_mon != NULL) {
UDEV_udev_monitor_unref(udev_mon);
udev_mon = NULL;
}
if (udev != NULL) {
UDEV_udev_unref(udev);
udev = NULL;
}
UnloadUDEVLibrary();
SDL_UDEV_DelCallback(joystick_udev_callback);
SDL_UDEV_Quit();
#endif
}

Expand Down

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