ref: 8d296f03850a2b981a90a6a62bb3663bd9effd4f
dir: /external/glfw/src/linux_joystick.c/
//========================================================================
// GLFW 3.3 Linux - www.glfw.org
//------------------------------------------------------------------------
// Copyright (c) 2002-2006 Marcus Geelnard
// Copyright (c) 2006-2017 Camilla Löwy <elmindreda@glfw.org>
//
// This software is provided 'as-is', without any express or implied
// warranty. In no event will the authors be held liable for any damages
// arising from the use of this software.
//
// Permission is granted to anyone to use this software for any purpose,
// including commercial applications, and to alter it and redistribute it
// freely, subject to the following restrictions:
//
// 1. The origin of this software must not be misrepresented; you must not
// claim that you wrote the original software. If you use this software
// in a product, an acknowledgment in the product documentation would
// be appreciated but is not required.
//
// 2. Altered source versions must be plainly marked as such, and must not
// be misrepresented as being the original software.
//
// 3. This notice may not be removed or altered from any source
// distribution.
//
//========================================================================
// It is fine to use C99 in this file because it will not be built with VS
//========================================================================
#include "internal.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/inotify.h>
#include <fcntl.h>
#include <errno.h>
#include <dirent.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#ifndef SYN_DROPPED // < v2.6.39 kernel headers
// Workaround for CentOS-6, which is supported till 2020-11-30, but still on v2.6.32
#define SYN_DROPPED 3
#endif
// Apply an EV_KEY event to the specified joystick
//
static void handleKeyEvent(_GLFWjoystick* js, int code, int value)
{
_glfwInputJoystickButton(js,
js->linjs.keyMap[code - BTN_MISC],
value ? GLFW_PRESS : GLFW_RELEASE);
}
// Apply an EV_ABS event to the specified joystick
//
static void handleAbsEvent(_GLFWjoystick* js, int code, int value)
{
const int index = js->linjs.absMap[code];
if (code >= ABS_HAT0X && code <= ABS_HAT3Y)
{
static const char stateMap[3][3] =
{
{ GLFW_HAT_CENTERED, GLFW_HAT_UP, GLFW_HAT_DOWN },
{ GLFW_HAT_LEFT, GLFW_HAT_LEFT_UP, GLFW_HAT_LEFT_DOWN },
{ GLFW_HAT_RIGHT, GLFW_HAT_RIGHT_UP, GLFW_HAT_RIGHT_DOWN },
};
const int hat = (code - ABS_HAT0X) / 2;
const int axis = (code - ABS_HAT0X) % 2;
int* state = js->linjs.hats[hat];
// NOTE: Looking at several input drivers, it seems all hat events use
// -1 for left / up, 0 for centered and 1 for right / down
if (value == 0)
state[axis] = 0;
else if (value < 0)
state[axis] = 1;
else if (value > 0)
state[axis] = 2;
_glfwInputJoystickHat(js, index, stateMap[state[0]][state[1]]);
}
else
{
const struct input_absinfo* info = &js->linjs.absInfo[code];
float normalized = value;
const int range = info->maximum - info->minimum;
if (range)
{
// Normalize to 0.0 -> 1.0
normalized = (normalized - info->minimum) / range;
// Normalize to -1.0 -> 1.0
normalized = normalized * 2.0f - 1.0f;
}
_glfwInputJoystickAxis(js, index, normalized);
}
}
// Poll state of absolute axes
//
static void pollAbsState(_GLFWjoystick* js)
{
for (int code = 0; code < ABS_CNT; code++)
{
if (js->linjs.absMap[code] < 0)
continue;
struct input_absinfo* info = &js->linjs.absInfo[code];
if (ioctl(js->linjs.fd, EVIOCGABS(code), info) < 0)
continue;
handleAbsEvent(js, code, info->value);
}
}
#define isBitSet(bit, arr) (arr[(bit) / 8] & (1 << ((bit) % 8)))
// Attempt to open the specified joystick device
//
static GLFWbool openJoystickDevice(const char* path)
{
for (int jid = 0; jid <= GLFW_JOYSTICK_LAST; jid++)
{
if (!_glfw.joysticks[jid].present)
continue;
if (strcmp(_glfw.joysticks[jid].linjs.path, path) == 0)
return GLFW_FALSE;
}
_GLFWjoystickLinux linjs = {0};
linjs.fd = open(path, O_RDONLY | O_NONBLOCK);
if (linjs.fd == -1)
return GLFW_FALSE;
char evBits[(EV_CNT + 7) / 8] = {0};
char keyBits[(KEY_CNT + 7) / 8] = {0};
char absBits[(ABS_CNT + 7) / 8] = {0};
struct input_id id;
if (ioctl(linjs.fd, EVIOCGBIT(0, sizeof(evBits)), evBits) < 0 ||
ioctl(linjs.fd, EVIOCGBIT(EV_KEY, sizeof(keyBits)), keyBits) < 0 ||
ioctl(linjs.fd, EVIOCGBIT(EV_ABS, sizeof(absBits)), absBits) < 0 ||
ioctl(linjs.fd, EVIOCGID, &id) < 0)
{
_glfwInputError(GLFW_PLATFORM_ERROR,
"Linux: Failed to query input device: %s",
strerror(errno));
close(linjs.fd);
return GLFW_FALSE;
}
// Ensure this device supports the events expected of a joystick
if (!isBitSet(EV_KEY, evBits) || !isBitSet(EV_ABS, evBits))
{
close(linjs.fd);
return GLFW_FALSE;
}
char name[256] = "";
if (ioctl(linjs.fd, EVIOCGNAME(sizeof(name)), name) < 0)
strncpy(name, "Unknown", sizeof(name));
char guid[33] = "";
// Generate a joystick GUID that matches the SDL 2.0.5+ one
if (id.vendor && id.product && id.version)
{
sprintf(guid, "%02x%02x0000%02x%02x0000%02x%02x0000%02x%02x0000",
id.bustype & 0xff, id.bustype >> 8,
id.vendor & 0xff, id.vendor >> 8,
id.product & 0xff, id.product >> 8,
id.version & 0xff, id.version >> 8);
}
else
{
sprintf(guid, "%02x%02x0000%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x00",
id.bustype & 0xff, id.bustype >> 8,
name[0], name[1], name[2], name[3],
name[4], name[5], name[6], name[7],
name[8], name[9], name[10]);
}
int axisCount = 0, buttonCount = 0, hatCount = 0;
for (int code = BTN_MISC; code < KEY_CNT; code++)
{
if (!isBitSet(code, keyBits))
continue;
linjs.keyMap[code - BTN_MISC] = buttonCount;
buttonCount++;
}
for (int code = 0; code < ABS_CNT; code++)
{
linjs.absMap[code] = -1;
if (!isBitSet(code, absBits))
continue;
if (code >= ABS_HAT0X && code <= ABS_HAT3Y)
{
linjs.absMap[code] = hatCount;
hatCount++;
// Skip the Y axis
code++;
}
else
{
if (ioctl(linjs.fd, EVIOCGABS(code), &linjs.absInfo[code]) < 0)
continue;
linjs.absMap[code] = axisCount;
axisCount++;
}
}
_GLFWjoystick* js =
_glfwAllocJoystick(name, guid, axisCount, buttonCount, hatCount);
if (!js)
{
close(linjs.fd);
return GLFW_FALSE;
}
strncpy(linjs.path, path, sizeof(linjs.path) - 1);
memcpy(&js->linjs, &linjs, sizeof(linjs));
pollAbsState(js);
_glfwInputJoystick(js, GLFW_CONNECTED);
return GLFW_TRUE;
}
#undef isBitSet
// Frees all resources associated with the specified joystick
//
static void closeJoystick(_GLFWjoystick* js)
{
close(js->linjs.fd);
_glfwFreeJoystick(js);
_glfwInputJoystick(js, GLFW_DISCONNECTED);
}
// Lexically compare joysticks by name; used by qsort
//
static int compareJoysticks(const void* fp, const void* sp)
{
const _GLFWjoystick* fj = fp;
const _GLFWjoystick* sj = sp;
return strcmp(fj->linjs.path, sj->linjs.path);
}
//////////////////////////////////////////////////////////////////////////
////// GLFW internal API //////
//////////////////////////////////////////////////////////////////////////
// Initialize joystick interface
//
GLFWbool _glfwInitJoysticksLinux(void)
{
const char* dirname = "/dev/input";
_glfw.linjs.inotify = inotify_init1(IN_NONBLOCK | IN_CLOEXEC);
if (_glfw.linjs.inotify > 0)
{
// HACK: Register for IN_ATTRIB to get notified when udev is done
// This works well in practice but the true way is libudev
_glfw.linjs.watch = inotify_add_watch(_glfw.linjs.inotify,
dirname,
IN_CREATE | IN_ATTRIB | IN_DELETE);
}
// Continue without device connection notifications if inotify fails
if (regcomp(&_glfw.linjs.regex, "^event[0-9]\\+$", 0) != 0)
{
_glfwInputError(GLFW_PLATFORM_ERROR, "Linux: Failed to compile regex");
return GLFW_FALSE;
}
int count = 0;
DIR* dir = opendir(dirname);
if (dir)
{
struct dirent* entry;
while ((entry = readdir(dir)))
{
regmatch_t match;
if (regexec(&_glfw.linjs.regex, entry->d_name, 1, &match, 0) != 0)
continue;
char path[PATH_MAX];
snprintf(path, sizeof(path), "%s/%s", dirname, entry->d_name);
if (openJoystickDevice(path))
count++;
}
closedir(dir);
}
// Continue with no joysticks if enumeration fails
qsort(_glfw.joysticks, count, sizeof(_GLFWjoystick), compareJoysticks);
return GLFW_TRUE;
}
// Close all opened joystick handles
//
void _glfwTerminateJoysticksLinux(void)
{
int jid;
for (jid = 0; jid <= GLFW_JOYSTICK_LAST; jid++)
{
_GLFWjoystick* js = _glfw.joysticks + jid;
if (js->present)
closeJoystick(js);
}
regfree(&_glfw.linjs.regex);
if (_glfw.linjs.inotify > 0)
{
if (_glfw.linjs.watch > 0)
inotify_rm_watch(_glfw.linjs.inotify, _glfw.linjs.watch);
close(_glfw.linjs.inotify);
}
}
void _glfwDetectJoystickConnectionLinux(void)
{
if (_glfw.linjs.inotify <= 0)
return;
ssize_t offset = 0;
char buffer[16384];
const ssize_t size = read(_glfw.linjs.inotify, buffer, sizeof(buffer));
while (size > offset)
{
regmatch_t match;
const struct inotify_event* e = (struct inotify_event*) (buffer + offset);
offset += sizeof(struct inotify_event) + e->len;
if (regexec(&_glfw.linjs.regex, e->name, 1, &match, 0) != 0)
continue;
char path[PATH_MAX];
snprintf(path, sizeof(path), "/dev/input/%s", e->name);
if (e->mask & (IN_CREATE | IN_ATTRIB))
openJoystickDevice(path);
else if (e->mask & IN_DELETE)
{
for (int jid = 0; jid <= GLFW_JOYSTICK_LAST; jid++)
{
if (strcmp(_glfw.joysticks[jid].linjs.path, path) == 0)
{
closeJoystick(_glfw.joysticks + jid);
break;
}
}
}
}
}
//////////////////////////////////////////////////////////////////////////
////// GLFW platform API //////
//////////////////////////////////////////////////////////////////////////
int _glfwPlatformPollJoystick(_GLFWjoystick* js, int mode)
{
// Read all queued events (non-blocking)
for (;;)
{
struct input_event e;
errno = 0;
if (read(js->linjs.fd, &e, sizeof(e)) < 0)
{
// Reset the joystick slot if the device was disconnected
if (errno == ENODEV)
closeJoystick(js);
break;
}
if (e.type == EV_SYN)
{
if (e.code == SYN_DROPPED)
_glfw.linjs.dropped = GLFW_TRUE;
else if (e.code == SYN_REPORT)
{
_glfw.linjs.dropped = GLFW_FALSE;
pollAbsState(js);
}
}
if (_glfw.linjs.dropped)
continue;
if (e.type == EV_KEY)
handleKeyEvent(js, e.code, e.value);
else if (e.type == EV_ABS)
handleAbsEvent(js, e.code, e.value);
}
return js->present;
}
void _glfwPlatformUpdateGamepadGUID(char* guid)
{
}