xref: /src/lib/libusbhid/parse.c

/*	$NetBSD: parse.c,v 1.11 2020/04/04 21:26:16 fox Exp $	*/

/*
 * Copyright (c) 1999, 2001 Lennart Augustsson <augustss (at) NetBSD.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>
__RCSID("$NetBSD: parse.c,v 1.11 2020/04/04 21:26:16 fox Exp $");

#include <assert.h>
#include <stdlib.h>
#include <string.h>
#include <sys/time.h>

#include <dev/usb/usb.h>
#include <dev/hid/hid.h>

#include "usbhid.h"
#include "usbvar.h"

#define MAXUSAGE 100
struct hid_data {
	u_char *start;
	u_char *end;
	u_char *p;
	hid_item_t cur;
	unsigned int usages[MAXUSAGE];
	int nusage;
	int minset;
	int logminsize;
	int phyminsize;
	int multi;
	int multimax;
	int kindset;
	int reportid;

	/*
	 * The start of collection item has no report ID set, so save
	 * it until we know the ID.
	 */
	hid_item_t savedcoll;
	u_char hassavedcoll;
	/*
	 * Absolute data position (bits) for input/output/feature.
	 *  Assumes that hid_input, hid_output and hid_feature have
	 *  values 0, 1 and 2.
	 */
	unsigned int kindpos[3];
};

static int min(int x, int y) { return x < y ? x : y; }

static int hid_get_item_raw(hid_data_t s, hid_item_t *h);

static void
hid_clear_local(hid_item_t *c)
{

	_DIAGASSERT(c != NULL);

	c->usage = 0;
	c->usage_minimum = 0;
	c->usage_maximum = 0;
	c->designator_index = 0;
	c->designator_minimum = 0;
	c->designator_maximum = 0;
	c->string_index = 0;
	c->string_minimum = 0;
	c->string_maximum = 0;
	c->set_delimiter = 0;
}

hid_data_t
hid_start_parse(report_desc_t d, int kindset, int id)
{
	struct hid_data *s;

	_DIAGASSERT(d != NULL);

	s = malloc(sizeof *s);
	memset(s, 0, sizeof *s);
	s->start = s->p = d->data;
	s->end = d->data + d->size;
	s->kindset = kindset;
	s->reportid = id;
	s->hassavedcoll = 0;
	return (s);
}

void
hid_end_parse(hid_data_t s)
{

	_DIAGASSERT(s != NULL);

	while (s->cur.next) {
		hid_item_t *hi = s->cur.next->next;
		free(s->cur.next);
		s->cur.next = hi;
	}
	free(s);
}

int
hid_get_item(hid_data_t s, hid_item_t *h)
{
	int r;

	for (;;) {
		r = hid_get_item_raw(s, h);
		if (r <= 0)
			break;
		if (h->report_ID == s->reportid || s->reportid == -1)
			break;
	}
	return (r);
}

#define REPORT_SAVED_COLL \
	do { \
		if (s->hassavedcoll) { \
			*h = s->savedcoll; \
			h->report_ID = c->report_ID; \
			s->hassavedcoll = 0; \
			return (1); \
		} \
	} while(/*LINTED*/ 0)

static int
hid_get_item_raw(hid_data_t s, hid_item_t *h)
{
	hid_item_t *c;
	unsigned int bTag = 0, bType = 0, bSize;
	unsigned char *data;
	int dval;
	unsigned char *p;
	hid_item_t *hi;
	hid_item_t nc;
	int i;
	hid_kind_t retkind;

	_DIAGASSERT(s != NULL);
	_DIAGASSERT(h != NULL);

	c = &s->cur;

 top:
	if (s->multimax) {
		REPORT_SAVED_COLL;
		if (c->logical_minimum >= c->logical_maximum) {
			if (s->logminsize == 1)
				c->logical_minimum =(int8_t)c->logical_minimum;
			else if (s->logminsize == 2)
				c->logical_minimum =(int16_t)c->logical_minimum;
		}
		if (c->physical_minimum >= c->physical_maximum) {
			if (s->phyminsize == 1)
				c->physical_minimum =
					(int8_t)c->physical_minimum;
			else if (s->phyminsize == 2)
				c->physical_minimum =
					(int16_t)c->physical_minimum;
		}
		if (s->multi < s->multimax) {
			c->usage = s->usages[min(s->multi, s->nusage-1)];
			s->multi++;
			*h = *c;
			/*
			 * 'multimax' is only non-zero if the current
                         *  item kind is input/output/feature
			 */
			h->pos = s->kindpos[c->kind];
			s->kindpos[c->kind] += c->report_size;
			h->next = 0;
			return (1);
		} else {
			c->report_count = s->multimax;
			s->multimax = 0;
			s->nusage = 0;
			hid_clear_local(c);
		}
	}
	for (;;) {
		p = s->p;
		if (p >= s->end)
			return (0);

		bSize = *p++;
		if (bSize == 0xfe) {
			/* long item */
			bSize = *p++;
			bSize |= *p++ << 8;
			bTag = *p++;
			data = p;
			p += bSize;
		} else {
			/* short item */
			bTag = bSize >> 4;
			bType = (bSize >> 2) & 3;
			bSize &= 3;
			if (bSize == 3) bSize = 4;
			data = p;
			p += bSize;
		}
		s->p = p;
		/*
		 * The spec is unclear if the data is signed or unsigned.
		 */
		switch(bSize) {
		case 0:
			dval = 0;
			break;
		case 1:
			dval = /*(int8_t)*/*data++;
			break;
		case 2:
			dval = *data++;
			dval |= *data++ << 8;
			break;
		case 4:
			dval = *data++;
			dval |= *data++ << 8;
			dval |= *data++ << 16;
			dval |= ((uint32_t)*data++) << 24;
			break;
		default:
			return (-1);
		}

		switch (bType) {
		case 0:			/* Main */
			switch (bTag) {
			case 8:		/* Input */
				retkind = hid_input;
			ret:
				if (!(s->kindset & (1 << retkind))) {
					/* Drop the items of this kind */
					s->nusage = 0;
					continue;
				}
				c->kind = retkind;
				c->flags = dval;
				if (c->flags & HIO_VARIABLE) {
					s->multimax = c->report_count;
					s->multi = 0;
					c->report_count = 1;
					if (s->minset) {
						for (i = c->usage_minimum;
						     i <= c->usage_maximum;
						     i++) {
							s->usages[s->nusage] = i;
							if (s->nusage < MAXUSAGE-1)
								s->nusage++;
						}
						c->usage_minimum = 0;
						c->usage_maximum = 0;
						s->minset = 0;
					}
					goto top;
				} else {
					if (s->minset)
						c->usage = c->usage_minimum;
					*h = *c;
					h->next = 0;
					h->pos = s->kindpos[c->kind];
					s->kindpos[c->kind] +=
					    c->report_size * c->report_count;
					hid_clear_local(c);
					s->minset = 0;
					return (1);
				}
			case 9:		/* Output */
				retkind = hid_output;
				goto ret;
			case 10:	/* Collection */
				c->kind = hid_collection;
				c->collection = dval;
				c->collevel++;
				nc = *c;
				hid_clear_local(c);
				/*c->report_ID = NO_REPORT_ID;*/
				s->nusage = 0;
				if (s->hassavedcoll) {
					*h = s->savedcoll;
					h->report_ID = nc.report_ID;
					s->savedcoll = nc;
					return (1);
				} else {
					s->hassavedcoll = 1;
					s->savedcoll = nc;
				}
				break;
			case 11:	/* Feature */
				retkind = hid_feature;
				goto ret;
			case 12:	/* End collection */
				REPORT_SAVED_COLL;
				c->kind = hid_endcollection;
				c->collevel--;
				*h = *c;
				/*hid_clear_local(c);*/
				s->nusage = 0;
				return (1);
			default:
				return (-2);
			}
			break;

		case 1:		/* Global */
			switch (bTag) {
			case 0:
				c->_usage_page = dval << 16;
				break;
			case 1:
				c->logical_minimum = dval;
				s->logminsize = bSize;
				break;
			case 2:
				c->logical_maximum = dval;
				break;
			case 3:
				c->physical_minimum = dval;
				s->phyminsize = bSize;
				break;
			case 4:
				c->physical_maximum = dval;
				break;
			case 5:
				if ( dval > 7 && dval < 0x10)
					c->unit_exponent = -16 + dval;
				else
					c->unit_exponent = dval;
				break;
			case 6:
				c->unit = dval;
				break;
			case 7:
				c->report_size = dval;
				break;
			case 8:
				c->report_ID = dval;
				s->kindpos[hid_input] =
				    s->kindpos[hid_output] =
				    s->kindpos[hid_feature] = 0;
				break;
			case 9:
				c->report_count = dval;
				break;
			case 10: /* Push */
				hi = malloc(sizeof *hi);
				*hi = s->cur;
				c->next = hi;
				break;
			case 11: /* Pop */
				hi = c->next;
				if (hi == NULL)
					break;
				s->cur = *hi;
				free(hi);
				break;
			default:
				return (-3);
			}
			break;
		case 2:		/* Local */
			switch (bTag) {
			case 0:
				c->usage = c->_usage_page | dval;
				if (s->nusage < MAXUSAGE)
					s->usages[s->nusage++] = c->usage;
				/* else XXX */
				break;
			case 1:
				s->minset = 1;
				c->usage_minimum = c->_usage_page | dval;
				break;
			case 2:
				c->usage_maximum = c->_usage_page | dval;
				break;
			case 3:
				c->designator_index = dval;
				break;
			case 4:
				c->designator_minimum = dval;
				break;
			case 5:
				c->designator_maximum = dval;
				break;
			case 7:
				c->string_index = dval;
				break;
			case 8:
				c->string_minimum = dval;
				break;
			case 9:
				c->string_maximum = dval;
				break;
			case 10:
				c->set_delimiter = dval;
				break;
			default:
				return (-4);
			}
			break;
		default:
			return (-5);
		}
	}
}

int
hid_report_size(report_desc_t r, enum hid_kind k, int id)
{
	struct hid_data *d;
	hid_item_t h;
	int size;

	_DIAGASSERT(r != NULL);

	memset(&h, 0, sizeof h);
	size = 0;
	for (d = hid_start_parse(r, 1<<k, id); hid_get_item(d, &h); ) {
		if (h.report_ID == id && h.kind == k) {
			size = d->kindpos[k];
		}
	}
	hid_end_parse(d);
	return ((size + 7) / 8);
}

int
hid_locate(report_desc_t desc, unsigned int u, enum hid_kind k,
	   hid_item_t *h, int id)
{
	hid_data_t d;

	_DIAGASSERT(desc != NULL);
	_DIAGASSERT(h != NULL);

	for (d = hid_start_parse(desc, 1<<k, id); hid_get_item(d, h); ) {
		if (h->kind == k && !(h->flags & HIO_CONST) && h->usage == u) {
			hid_end_parse(d);
			return (1);
		}
	}
	hid_end_parse(d);
	h->report_size = 0;
	return (0);
}