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cpputils / deps / glfw / src / linux_joystick.c
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1//========================================================================
2// GLFW 3.3 Linux - www.glfw.org
3//------------------------------------------------------------------------
4// Copyright (c) 2002-2006 Marcus Geelnard
5// Copyright (c) 2006-2017 Camilla Löwy <elmindreda@glfw.org>
6//
7// This software is provided 'as-is', without any express or implied
8// warranty. In no event will the authors be held liable for any damages
9// arising from the use of this software.
10//
11// Permission is granted to anyone to use this software for any purpose,
12// including commercial applications, and to alter it and redistribute it
13// freely, subject to the following restrictions:
14//
15// 1. The origin of this software must not be misrepresented; you must not
16// claim that you wrote the original software. If you use this software
17// in a product, an acknowledgment in the product documentation would
18// be appreciated but is not required.
19//
20// 2. Altered source versions must be plainly marked as such, and must not
21// be misrepresented as being the original software.
22//
23// 3. This notice may not be removed or altered from any source
24// distribution.
25//
26//========================================================================
27// It is fine to use C99 in this file because it will not be built with VS
28//========================================================================
29
30#include "internal.h"
31
32#include <sys/types.h>
33#include <sys/stat.h>
34#include <sys/inotify.h>
35#include <fcntl.h>
36#include <errno.h>
37#include <dirent.h>
38#include <stdio.h>
39#include <stdlib.h>
40#include <string.h>
41#include <unistd.h>
42
43#ifndef SYN_DROPPED // < v2.6.39 kernel headers
44// Workaround for CentOS-6, which is supported till 2020-11-30, but still on v2.6.32
45#define SYN_DROPPED 3
46#endif
47
48// Apply an EV_KEY event to the specified joystick
49//
50static void handleKeyEvent(_GLFWjoystick* js, int code, int value)
51{
52 _glfwInputJoystickButton(js,
53 js->linjs.keyMap[code - BTN_MISC],
54 value ? GLFW_PRESS : GLFW_RELEASE);
55}
56
57// Apply an EV_ABS event to the specified joystick
58//
59static void handleAbsEvent(_GLFWjoystick* js, int code, int value)
60{
61 const int index = js->linjs.absMap[code];
62
63 if (code >= ABS_HAT0X && code <= ABS_HAT3Y)
64 {
65 static const char stateMap[3][3] =
66 {
67 { GLFW_HAT_CENTERED, GLFW_HAT_UP, GLFW_HAT_DOWN },
68 { GLFW_HAT_LEFT, GLFW_HAT_LEFT_UP, GLFW_HAT_LEFT_DOWN },
69 { GLFW_HAT_RIGHT, GLFW_HAT_RIGHT_UP, GLFW_HAT_RIGHT_DOWN },
70 };
71
72 const int hat = (code - ABS_HAT0X) / 2;
73 const int axis = (code - ABS_HAT0X) % 2;
74 int* state = js->linjs.hats[hat];
75
76 // NOTE: Looking at several input drivers, it seems all hat events use
77 // -1 for left / up, 0 for centered and 1 for right / down
78 if (value == 0)
79 state[axis] = 0;
80 else if (value < 0)
81 state[axis] = 1;
82 else if (value > 0)
83 state[axis] = 2;
84
85 _glfwInputJoystickHat(js, index, stateMap[state[0]][state[1]]);
86 }
87 else
88 {
89 const struct input_absinfo* info = &js->linjs.absInfo[code];
90 float normalized = value;
91
92 const int range = info->maximum - info->minimum;
93 if (range)
94 {
95 // Normalize to 0.0 -> 1.0
96 normalized = (normalized - info->minimum) / range;
97 // Normalize to -1.0 -> 1.0
98 normalized = normalized * 2.0f - 1.0f;
99 }
100
101 _glfwInputJoystickAxis(js, index, normalized);
102 }
103}
104
105// Poll state of absolute axes
106//
107static void pollAbsState(_GLFWjoystick* js)
108{
109 for (int code = 0; code < ABS_CNT; code++)
110 {
111 if (js->linjs.absMap[code] < 0)
112 continue;
113
114 struct input_absinfo* info = &js->linjs.absInfo[code];
115
116 if (ioctl(js->linjs.fd, EVIOCGABS(code), info) < 0)
117 continue;
118
119 handleAbsEvent(js, code, info->value);
120 }
121}
122
123#define isBitSet(bit, arr) (arr[(bit) / 8] & (1 << ((bit) % 8)))
124
125// Attempt to open the specified joystick device
126//
127static GLFWbool openJoystickDevice(const char* path)
128{
129 for (int jid = 0; jid <= GLFW_JOYSTICK_LAST; jid++)
130 {
131 if (!_glfw.joysticks[jid].present)
132 continue;
133 if (strcmp(_glfw.joysticks[jid].linjs.path, path) == 0)
134 return GLFW_FALSE;
135 }
136
137 _GLFWjoystickLinux linjs = {0};
138 linjs.fd = open(path, O_RDONLY | O_NONBLOCK);
139 if (linjs.fd == -1)
140 return GLFW_FALSE;
141
142 char evBits[(EV_CNT + 7) / 8] = {0};
143 char keyBits[(KEY_CNT + 7) / 8] = {0};
144 char absBits[(ABS_CNT + 7) / 8] = {0};
145 struct input_id id;
146
147 if (ioctl(linjs.fd, EVIOCGBIT(0, sizeof(evBits)), evBits) < 0 ||
148 ioctl(linjs.fd, EVIOCGBIT(EV_KEY, sizeof(keyBits)), keyBits) < 0 ||
149 ioctl(linjs.fd, EVIOCGBIT(EV_ABS, sizeof(absBits)), absBits) < 0 ||
150 ioctl(linjs.fd, EVIOCGID, &id) < 0)
151 {
152 _glfwInputError(GLFW_PLATFORM_ERROR,
153 "Linux: Failed to query input device: %s",
154 strerror(errno));
155 close(linjs.fd);
156 return GLFW_FALSE;
157 }
158
159 // Ensure this device supports the events expected of a joystick
160 if (!isBitSet(EV_KEY, evBits) || !isBitSet(EV_ABS, evBits))
161 {
162 close(linjs.fd);
163 return GLFW_FALSE;
164 }
165
166 char name[256] = "";
167
168 if (ioctl(linjs.fd, EVIOCGNAME(sizeof(name)), name) < 0)
169 strncpy(name, "Unknown", sizeof(name));
170
171 char guid[33] = "";
172
173 // Generate a joystick GUID that matches the SDL 2.0.5+ one
174 if (id.vendor && id.product && id.version)
175 {
176 sprintf(guid, "%02x%02x0000%02x%02x0000%02x%02x0000%02x%02x0000",
177 id.bustype & 0xff, id.bustype >> 8,
178 id.vendor & 0xff, id.vendor >> 8,
179 id.product & 0xff, id.product >> 8,
180 id.version & 0xff, id.version >> 8);
181 }
182 else
183 {
184 sprintf(guid, "%02x%02x0000%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x00",
185 id.bustype & 0xff, id.bustype >> 8,
186 name[0], name[1], name[2], name[3],
187 name[4], name[5], name[6], name[7],
188 name[8], name[9], name[10]);
189 }
190
191 int axisCount = 0, buttonCount = 0, hatCount = 0;
192
193 for (int code = BTN_MISC; code < KEY_CNT; code++)
194 {
195 if (!isBitSet(code, keyBits))
196 continue;
197
198 linjs.keyMap[code - BTN_MISC] = buttonCount;
199 buttonCount++;
200 }
201
202 for (int code = 0; code < ABS_CNT; code++)
203 {
204 linjs.absMap[code] = -1;
205 if (!isBitSet(code, absBits))
206 continue;
207
208 if (code >= ABS_HAT0X && code <= ABS_HAT3Y)
209 {
210 linjs.absMap[code] = hatCount;
211 hatCount++;
212 // Skip the Y axis
213 code++;
214 }
215 else
216 {
217 if (ioctl(linjs.fd, EVIOCGABS(code), &linjs.absInfo[code]) < 0)
218 continue;
219
220 linjs.absMap[code] = axisCount;
221 axisCount++;
222 }
223 }
224
225 _GLFWjoystick* js =
226 _glfwAllocJoystick(name, guid, axisCount, buttonCount, hatCount);
227 if (!js)
228 {
229 close(linjs.fd);
230 return GLFW_FALSE;
231 }
232
233 strncpy(linjs.path, path, sizeof(linjs.path) - 1);
234 memcpy(&js->linjs, &linjs, sizeof(linjs));
235
236 pollAbsState(js);
237
238 _glfwInputJoystick(js, GLFW_CONNECTED);
239 return GLFW_TRUE;
240}
241
242#undef isBitSet
243
244// Frees all resources associated with the specified joystick
245//
246static void closeJoystick(_GLFWjoystick* js)
247{
248 close(js->linjs.fd);
249 _glfwFreeJoystick(js);
250 _glfwInputJoystick(js, GLFW_DISCONNECTED);
251}
252
253// Lexically compare joysticks by name; used by qsort
254//
255static int compareJoysticks(const void* fp, const void* sp)
256{
257 const _GLFWjoystick* fj = fp;
258 const _GLFWjoystick* sj = sp;
259 return strcmp(fj->linjs.path, sj->linjs.path);
260}
261
262
263//////////////////////////////////////////////////////////////////////////
264////// GLFW internal API //////
265//////////////////////////////////////////////////////////////////////////
266
267// Initialize joystick interface
268//
269GLFWbool _glfwInitJoysticksLinux(void)
270{
271 const char* dirname = "/dev/input";
272
273 _glfw.linjs.inotify = inotify_init1(IN_NONBLOCK | IN_CLOEXEC);
274 if (_glfw.linjs.inotify > 0)
275 {
276 // HACK: Register for IN_ATTRIB to get notified when udev is done
277 // This works well in practice but the true way is libudev
278
279 _glfw.linjs.watch = inotify_add_watch(_glfw.linjs.inotify,
280 dirname,
281 IN_CREATE | IN_ATTRIB | IN_DELETE);
282 }
283
284 // Continue without device connection notifications if inotify fails
285
286 if (regcomp(&_glfw.linjs.regex, "^event[0-9]\\+$", 0) != 0)
287 {
288 _glfwInputError(GLFW_PLATFORM_ERROR, "Linux: Failed to compile regex");
289 return GLFW_FALSE;
290 }
291
292 int count = 0;
293
294 DIR* dir = opendir(dirname);
295 if (dir)
296 {
297 struct dirent* entry;
298
299 while ((entry = readdir(dir)))
300 {
301 regmatch_t match;
302
303 if (regexec(&_glfw.linjs.regex, entry->d_name, 1, &match, 0) != 0)
304 continue;
305
306 char path[PATH_MAX];
307
308 snprintf(path, sizeof(path), "%s/%s", dirname, entry->d_name);
309
310 if (openJoystickDevice(path))
311 count++;
312 }
313
314 closedir(dir);
315 }
316
317 // Continue with no joysticks if enumeration fails
318
319 qsort(_glfw.joysticks, count, sizeof(_GLFWjoystick), compareJoysticks);
320 return GLFW_TRUE;
321}
322
323// Close all opened joystick handles
324//
325void _glfwTerminateJoysticksLinux(void)
326{
327 int jid;
328
329 for (jid = 0; jid <= GLFW_JOYSTICK_LAST; jid++)
330 {
331 _GLFWjoystick* js = _glfw.joysticks + jid;
332 if (js->present)
333 closeJoystick(js);
334 }
335
336 regfree(&_glfw.linjs.regex);
337
338 if (_glfw.linjs.inotify > 0)
339 {
340 if (_glfw.linjs.watch > 0)
341 inotify_rm_watch(_glfw.linjs.inotify, _glfw.linjs.watch);
342
343 close(_glfw.linjs.inotify);
344 }
345}
346
347void _glfwDetectJoystickConnectionLinux(void)
348{
349 if (_glfw.linjs.inotify <= 0)
350 return;
351
352 ssize_t offset = 0;
353 char buffer[16384];
354 const ssize_t size = read(_glfw.linjs.inotify, buffer, sizeof(buffer));
355
356 while (size > offset)
357 {
358 regmatch_t match;
359 const struct inotify_event* e = (struct inotify_event*) (buffer + offset);
360
361 offset += sizeof(struct inotify_event) + e->len;
362
363 if (regexec(&_glfw.linjs.regex, e->name, 1, &match, 0) != 0)
364 continue;
365
366 char path[PATH_MAX];
367 snprintf(path, sizeof(path), "/dev/input/%s", e->name);
368
369 if (e->mask & (IN_CREATE | IN_ATTRIB))
370 openJoystickDevice(path);
371 else if (e->mask & IN_DELETE)
372 {
373 for (int jid = 0; jid <= GLFW_JOYSTICK_LAST; jid++)
374 {
375 if (strcmp(_glfw.joysticks[jid].linjs.path, path) == 0)
376 {
377 closeJoystick(_glfw.joysticks + jid);
378 break;
379 }
380 }
381 }
382 }
383}
384
385
386//////////////////////////////////////////////////////////////////////////
387////// GLFW platform API //////
388//////////////////////////////////////////////////////////////////////////
389
390int _glfwPlatformPollJoystick(_GLFWjoystick* js, int mode)
391{
392 // Read all queued events (non-blocking)
393 for (;;)
394 {
395 struct input_event e;
396
397 errno = 0;
398 if (read(js->linjs.fd, &e, sizeof(e)) < 0)
399 {
400 // Reset the joystick slot if the device was disconnected
401 if (errno == ENODEV)
402 closeJoystick(js);
403
404 break;
405 }
406
407 if (e.type == EV_SYN)
408 {
409 if (e.code == SYN_DROPPED)
410 _glfw.linjs.dropped = GLFW_TRUE;
411 else if (e.code == SYN_REPORT)
412 {
413 _glfw.linjs.dropped = GLFW_FALSE;
414 pollAbsState(js);
415 }
416 }
417
418 if (_glfw.linjs.dropped)
419 continue;
420
421 if (e.type == EV_KEY)
422 handleKeyEvent(js, e.code, e.value);
423 else if (e.type == EV_ABS)
424 handleAbsEvent(js, e.code, e.value);
425 }
426
427 return js->present;
428}
429
430void _glfwPlatformUpdateGamepadGUID(char* guid)
431{
432}
433