1/*	$NetBSD: parse.c,v 1.11 2000/09/24 02:19:54 augustss Exp $	*/
2
3/*
4 * Copyright (c) 1999, 2001 Lennart Augustsson <augustss@netbsd.org>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29#include <sys/cdefs.h>
30__FBSDID("$FreeBSD: stable/11/lib/libusbhid/parse.c 361919 2020-06-08 09:33:37Z hselasky $");
31
32#include <assert.h>
33#include <stdlib.h>
34#include <string.h>
35#include <sys/time.h>
36
37#include <dev/usb/usb.h>
38#include <dev/usb/usbhid.h>
39
40#include "usbhid.h"
41#include "usbvar.h"
42
43#define	MAXUSAGE 100
44#define	MAXPUSH 4
45#define	MAXID 64
46#define	ITEMTYPES 3
47
48struct hid_pos_data {
49	int32_t rid;
50	uint32_t pos[ITEMTYPES];
51};
52
53struct hid_data {
54	const uint8_t *start;
55	const uint8_t *end;
56	const uint8_t *p;
57	struct hid_item cur[MAXPUSH];
58	struct hid_pos_data last_pos[MAXID];
59	uint32_t pos[ITEMTYPES];
60	int32_t usages_min[MAXUSAGE];
61	int32_t usages_max[MAXUSAGE];
62	int32_t usage_last;	/* last seen usage */
63	uint32_t loc_size;	/* last seen size */
64	uint32_t loc_count;	/* last seen count */
65	uint8_t	kindset;	/* we have 5 kinds so 8 bits are enough */
66	uint8_t	pushlevel;	/* current pushlevel */
67	uint8_t	ncount;		/* end usage item count */
68	uint8_t icount;		/* current usage item count */
69	uint8_t	nusage;		/* end "usages_min/max" index */
70	uint8_t	iusage;		/* current "usages_min/max" index */
71	uint8_t ousage;		/* current "usages_min/max" offset */
72	uint8_t	susage;		/* usage set flags */
73	int32_t	reportid;	/* requested report ID */
74};
75
76/*------------------------------------------------------------------------*
77 *	hid_clear_local
78 *------------------------------------------------------------------------*/
79static void
80hid_clear_local(hid_item_t *c)
81{
82
83	c->usage = 0;
84	c->usage_minimum = 0;
85	c->usage_maximum = 0;
86	c->designator_index = 0;
87	c->designator_minimum = 0;
88	c->designator_maximum = 0;
89	c->string_index = 0;
90	c->string_minimum = 0;
91	c->string_maximum = 0;
92	c->set_delimiter = 0;
93}
94
95static void
96hid_switch_rid(struct hid_data *s, struct hid_item *c, int32_t next_rID)
97{
98	uint8_t i, j;
99
100	/* check for same report ID - optimise */
101
102	if (c->report_ID == next_rID)
103		return;
104
105	/* save current position for current rID */
106
107	if (c->report_ID == 0) {
108		i = 0;
109	} else {
110		for (i = 1; i != MAXID; i++) {
111			if (s->last_pos[i].rid == c->report_ID)
112				break;
113			if (s->last_pos[i].rid == 0)
114				break;
115		}
116	}
117	if (i != MAXID) {
118		s->last_pos[i].rid = c->report_ID;
119		for (j = 0; j < ITEMTYPES; j++)
120			s->last_pos[i].pos[j] = s->pos[j];
121	}
122
123	/* store next report ID */
124
125	c->report_ID = next_rID;
126
127	/* lookup last position for next rID */
128
129	if (next_rID == 0) {
130		i = 0;
131	} else {
132		for (i = 1; i != MAXID; i++) {
133			if (s->last_pos[i].rid == next_rID)
134				break;
135			if (s->last_pos[i].rid == 0)
136				break;
137		}
138	}
139	if (i != MAXID) {
140		s->last_pos[i].rid = next_rID;
141		for (j = 0; j < ITEMTYPES; j++)
142			s->pos[j] = s->last_pos[i].pos[j];
143	} else {
144		for (j = 0; j < ITEMTYPES; j++)
145			s->pos[j] = 0;	/* Out of RID entries. */
146	}
147}
148
149/*------------------------------------------------------------------------*
150 *	hid_start_parse
151 *------------------------------------------------------------------------*/
152hid_data_t
153hid_start_parse(report_desc_t d, int kindset, int id)
154{
155	struct hid_data *s;
156
157	s = malloc(sizeof *s);
158	memset(s, 0, sizeof *s);
159	s->start = s->p = d->data;
160	s->end = d->data + d->size;
161	s->kindset = kindset;
162	s->reportid = id;
163	return (s);
164}
165
166/*------------------------------------------------------------------------*
167 *	hid_end_parse
168 *------------------------------------------------------------------------*/
169void
170hid_end_parse(hid_data_t s)
171{
172
173	if (s == NULL)
174		return;
175
176	free(s);
177}
178
179/*------------------------------------------------------------------------*
180 *	get byte from HID descriptor
181 *------------------------------------------------------------------------*/
182static uint8_t
183hid_get_byte(struct hid_data *s, const uint16_t wSize)
184{
185	const uint8_t *ptr;
186	uint8_t retval;
187
188	ptr = s->p;
189
190	/* check if end is reached */
191	if (ptr == s->end)
192		return (0);
193
194	/* read out a byte */
195	retval = *ptr;
196
197	/* check if data pointer can be advanced by "wSize" bytes */
198	if ((s->end - ptr) < wSize)
199		ptr = s->end;
200	else
201		ptr += wSize;
202
203	/* update pointer */
204	s->p = ptr;
205
206	return (retval);
207}
208
209/*------------------------------------------------------------------------*
210 *	hid_get_item
211 *------------------------------------------------------------------------*/
212static int
213hid_get_item_raw(hid_data_t s, hid_item_t *h)
214{
215	hid_item_t *c;
216	unsigned int bTag, bType, bSize;
217	int32_t mask;
218	int32_t dval;
219
220	if (s == NULL)
221		return (0);
222
223	c = &s->cur[s->pushlevel];
224
225 top:
226	/* check if there is an array of items */
227	if (s->icount < s->ncount) {
228		/* get current usage */
229		if (s->iusage < s->nusage) {
230			dval = s->usages_min[s->iusage] + s->ousage;
231			c->usage = dval;
232			s->usage_last = dval;
233			if (dval == s->usages_max[s->iusage]) {
234				s->iusage ++;
235				s->ousage = 0;
236			} else {
237				s->ousage ++;
238			}
239		} else {
240			/* Using last usage */
241			dval = s->usage_last;
242		}
243		s->icount ++;
244		/*
245		 * Only copy HID item, increment position and return
246		 * if correct kindset!
247		 */
248		if (s->kindset & (1 << c->kind)) {
249			*h = *c;
250			h->pos = s->pos[c->kind];
251			s->pos[c->kind] += c->report_size * c->report_count;
252			return (1);
253		}
254	}
255
256	/* reset state variables */
257	s->icount = 0;
258	s->ncount = 0;
259	s->iusage = 0;
260	s->nusage = 0;
261	s->susage = 0;
262	s->ousage = 0;
263	hid_clear_local(c);
264
265	/* get next item */
266	while (s->p != s->end) {
267
268		bSize = hid_get_byte(s, 1);
269		if (bSize == 0xfe) {
270			/* long item */
271			bSize = hid_get_byte(s, 1);
272			bSize |= hid_get_byte(s, 1) << 8;
273			bTag = hid_get_byte(s, 1);
274			bType = 0xff;	/* XXX what should it be */
275		} else {
276			/* short item */
277			bTag = bSize >> 4;
278			bType = (bSize >> 2) & 3;
279			bSize &= 3;
280			if (bSize == 3)
281				bSize = 4;
282		}
283
284		switch(bSize) {
285		case 0:
286			dval = 0;
287			mask = 0;
288			break;
289		case 1:
290			dval = (int8_t)hid_get_byte(s, 1);
291			mask = 0xFF;
292			break;
293		case 2:
294			dval = hid_get_byte(s, 1);
295			dval |= hid_get_byte(s, 1) << 8;
296			dval = (int16_t)dval;
297			mask = 0xFFFF;
298			break;
299		case 4:
300			dval = hid_get_byte(s, 1);
301			dval |= hid_get_byte(s, 1) << 8;
302			dval |= hid_get_byte(s, 1) << 16;
303			dval |= hid_get_byte(s, 1) << 24;
304			mask = 0xFFFFFFFF;
305			break;
306		default:
307			dval = hid_get_byte(s, bSize);
308			continue;
309		}
310
311		switch (bType) {
312		case 0:		/* Main */
313			switch (bTag) {
314			case 8:	/* Input */
315				c->kind = hid_input;
316				c->flags = dval;
317		ret:
318				c->report_count = s->loc_count;
319				c->report_size = s->loc_size;
320
321				if (c->flags & HIO_VARIABLE) {
322					/* range check usage count */
323					if (c->report_count > 255) {
324						s->ncount = 255;
325					} else
326						s->ncount = c->report_count;
327
328					/*
329					 * The "top" loop will return
330					 * one and one item:
331					 */
332					c->report_count = 1;
333					c->usage_minimum = 0;
334					c->usage_maximum = 0;
335				} else {
336					s->ncount = 1;
337				}
338				goto top;
339
340			case 9:	/* Output */
341				c->kind = hid_output;
342				c->flags = dval;
343				goto ret;
344			case 10:	/* Collection */
345				c->kind = hid_collection;
346				c->collection = dval;
347				c->collevel++;
348				c->usage = s->usage_last;
349				*h = *c;
350				return (1);
351			case 11:	/* Feature */
352				c->kind = hid_feature;
353				c->flags = dval;
354				goto ret;
355			case 12:	/* End collection */
356				c->kind = hid_endcollection;
357				if (c->collevel == 0) {
358					/* Invalid end collection. */
359					return (0);
360				}
361				c->collevel--;
362				*h = *c;
363				return (1);
364			default:
365				break;
366			}
367			break;
368
369		case 1:		/* Global */
370			switch (bTag) {
371			case 0:
372				c->_usage_page = dval << 16;
373				break;
374			case 1:
375				c->logical_minimum = dval;
376				break;
377			case 2:
378				c->logical_maximum = dval;
379				break;
380			case 3:
381				c->physical_minimum = dval;
382				break;
383			case 4:
384				c->physical_maximum = dval;
385				break;
386			case 5:
387				c->unit_exponent = dval;
388				break;
389			case 6:
390				c->unit = dval;
391				break;
392			case 7:
393				/* mask because value is unsigned */
394				s->loc_size = dval & mask;
395				break;
396			case 8:
397				hid_switch_rid(s, c, dval & mask);
398				break;
399			case 9:
400				/* mask because value is unsigned */
401				s->loc_count = dval & mask;
402				break;
403			case 10:	/* Push */
404				/* stop parsing, if invalid push level */
405				if ((s->pushlevel + 1) >= MAXPUSH)
406					return (0);
407				s->pushlevel ++;
408				s->cur[s->pushlevel] = *c;
409				/* store size and count */
410				c->report_size = s->loc_size;
411				c->report_count = s->loc_count;
412				/* update current item pointer */
413				c = &s->cur[s->pushlevel];
414				break;
415			case 11:	/* Pop */
416				/* stop parsing, if invalid push level */
417				if (s->pushlevel == 0)
418					return (0);
419				s->pushlevel --;
420				c = &s->cur[s->pushlevel];
421				/* restore size and count */
422				s->loc_size = c->report_size;
423				s->loc_count = c->report_count;
424				c->report_size = 0;
425				c->report_count = 0;
426				break;
427			default:
428				break;
429			}
430			break;
431		case 2:		/* Local */
432			switch (bTag) {
433			case 0:
434				if (bSize != 4)
435					dval = (dval & mask) | c->_usage_page;
436
437				/* set last usage, in case of a collection */
438				s->usage_last = dval;
439
440				if (s->nusage < MAXUSAGE) {
441					s->usages_min[s->nusage] = dval;
442					s->usages_max[s->nusage] = dval;
443					s->nusage ++;
444				}
445				/* else XXX */
446
447				/* clear any pending usage sets */
448				s->susage = 0;
449				break;
450			case 1:
451				s->susage |= 1;
452
453				if (bSize != 4)
454					dval = (dval & mask) | c->_usage_page;
455				c->usage_minimum = dval;
456
457				goto check_set;
458			case 2:
459				s->susage |= 2;
460
461				if (bSize != 4)
462					dval = (dval & mask) | c->_usage_page;
463				c->usage_maximum = dval;
464
465			check_set:
466				if (s->susage != 3)
467					break;
468
469				/* sanity check */
470				if ((s->nusage < MAXUSAGE) &&
471				    (c->usage_minimum <= c->usage_maximum)) {
472					/* add usage range */
473					s->usages_min[s->nusage] =
474					    c->usage_minimum;
475					s->usages_max[s->nusage] =
476					    c->usage_maximum;
477					s->nusage ++;
478				}
479				/* else XXX */
480
481				s->susage = 0;
482				break;
483			case 3:
484				c->designator_index = dval;
485				break;
486			case 4:
487				c->designator_minimum = dval;
488				break;
489			case 5:
490				c->designator_maximum = dval;
491				break;
492			case 7:
493				c->string_index = dval;
494				break;
495			case 8:
496				c->string_minimum = dval;
497				break;
498			case 9:
499				c->string_maximum = dval;
500				break;
501			case 10:
502				c->set_delimiter = dval;
503				break;
504			default:
505				break;
506			}
507			break;
508		default:
509			break;
510		}
511	}
512	return (0);
513}
514
515int
516hid_get_item(hid_data_t s, hid_item_t *h)
517{
518	int r;
519
520	for (;;) {
521		r = hid_get_item_raw(s, h);
522		if (r <= 0 || s->reportid == -1 || h->report_ID == s->reportid)
523			break;
524	}
525	return (r);
526}
527
528int
529hid_report_size(report_desc_t r, enum hid_kind k, int id)
530{
531	struct hid_data *d;
532	struct hid_item h;
533	uint32_t temp;
534	uint32_t hpos;
535	uint32_t lpos;
536	int report_id = 0;
537
538	hpos = 0;
539	lpos = 0xFFFFFFFF;
540
541	memset(&h, 0, sizeof h);
542	for (d = hid_start_parse(r, 1 << k, id); hid_get_item(d, &h); ) {
543		if (h.kind == k) {
544			/* compute minimum */
545			if (lpos > h.pos)
546				lpos = h.pos;
547			/* compute end position */
548			temp = h.pos + (h.report_size * h.report_count);
549			/* compute maximum */
550			if (hpos < temp)
551				hpos = temp;
552			if (h.report_ID != 0)
553				report_id = 1;
554		}
555	}
556	hid_end_parse(d);
557
558	/* safety check - can happen in case of currupt descriptors */
559	if (lpos > hpos)
560		temp = 0;
561	else
562		temp = hpos - lpos;
563
564	/* return length in bytes rounded up */
565	return ((temp + 7) / 8 + report_id);
566}
567
568int
569hid_locate(report_desc_t desc, unsigned int u, enum hid_kind k,
570	   hid_item_t *h, int id)
571{
572	struct hid_data *d;
573
574	for (d = hid_start_parse(desc, 1 << k, id); hid_get_item(d, h); ) {
575		if (h->kind == k && !(h->flags & HIO_CONST) && h->usage == u) {
576			hid_end_parse(d);
577			return (1);
578		}
579	}
580	hid_end_parse(d);
581	h->report_size = 0;
582	return (0);
583}
584