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hid.c
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hid.c
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/*******************************************************
HIDAPI - Multi-Platform library for
communication with HID devices.
Alan Ott
Signal 11 Software
libusb/hidapi Team
Copyright 2022, All Rights Reserved.
At the discretion of the user of this library,
this software may be licensed under the terms of the
GNU General Public License v3, a BSD-Style license, or the
original HIDAPI license as outlined in the LICENSE.txt,
LICENSE-gpl3.txt, LICENSE-bsd.txt, and LICENSE-orig.txt
files located at the root of the source distribution.
These files may also be found in the public source
code repository located at:
https://github.com/libusb/hidapi .
********************************************************/
#define _GNU_SOURCE /* needed for wcsdup() before glibc 2.10 */
/* C */
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <ctype.h>
#include <locale.h>
#include <errno.h>
/* Unix */
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <sys/utsname.h>
#include <fcntl.h>
#include <pthread.h>
#include <wchar.h>
/* GNU / LibUSB */
#include <libusb.h>
#if !defined(__ANDROID__) && !defined(NO_ICONV)
#include <iconv.h>
#ifndef ICONV_CONST
#define ICONV_CONST
#endif
#endif
#include "hidapi_libusb.h"
#if defined(__ANDROID__) && __ANDROID_API__ < __ANDROID_API_N__
/* Barrier implementation because Android/Bionic don't have pthread_barrier.
This implementation came from Brent Priddy and was posted on
StackOverflow. It is used with his permission. */
typedef int pthread_barrierattr_t;
typedef struct pthread_barrier {
pthread_mutex_t mutex;
pthread_cond_t cond;
int count;
int trip_count;
} pthread_barrier_t;
static int pthread_barrier_init(pthread_barrier_t *barrier, const pthread_barrierattr_t *attr, unsigned int count)
{
if(count == 0) {
errno = EINVAL;
return -1;
}
if(pthread_mutex_init(&barrier->mutex, 0) < 0) {
return -1;
}
if(pthread_cond_init(&barrier->cond, 0) < 0) {
pthread_mutex_destroy(&barrier->mutex);
return -1;
}
barrier->trip_count = count;
barrier->count = 0;
return 0;
}
static int pthread_barrier_destroy(pthread_barrier_t *barrier)
{
pthread_cond_destroy(&barrier->cond);
pthread_mutex_destroy(&barrier->mutex);
return 0;
}
static int pthread_barrier_wait(pthread_barrier_t *barrier)
{
pthread_mutex_lock(&barrier->mutex);
++(barrier->count);
if(barrier->count >= barrier->trip_count)
{
barrier->count = 0;
pthread_cond_broadcast(&barrier->cond);
pthread_mutex_unlock(&barrier->mutex);
return 1;
}
else
{
pthread_cond_wait(&barrier->cond, &(barrier->mutex));
pthread_mutex_unlock(&barrier->mutex);
return 0;
}
}
#endif
#ifdef __cplusplus
extern "C" {
#endif
#ifdef DEBUG_PRINTF
#define LOG(...) fprintf(stderr, __VA_ARGS__)
#else
#define LOG(...) do {} while (0)
#endif
#ifndef __FreeBSD__
#define DETACH_KERNEL_DRIVER
#endif
/* Uncomment to enable the retrieval of Usage and Usage Page in
hid_enumerate(). Warning, on platforms different from FreeBSD
this is very invasive as it requires the detach
and re-attach of the kernel driver. See comments inside hid_enumerate().
libusb HIDAPI programs are encouraged to use the interface number
instead to differentiate between interfaces on a composite HID device. */
/*#define INVASIVE_GET_USAGE*/
/* Linked List of input reports received from the device. */
struct input_report {
uint8_t *data;
size_t len;
struct input_report *next;
};
struct hid_device_ {
/* Handle to the actual device. */
libusb_device_handle *device_handle;
/* USB Configuration Number of the device */
int config_number;
/* The interface number of the HID */
int interface;
uint16_t report_descriptor_size;
/* Endpoint information */
int input_endpoint;
int output_endpoint;
int input_ep_max_packet_size;
/* Indexes of Strings */
int manufacturer_index;
int product_index;
int serial_index;
struct hid_device_info* device_info;
/* Whether blocking reads are used */
int blocking; /* boolean */
/* Read thread objects */
pthread_t thread;
pthread_mutex_t mutex; /* Protects input_reports */
pthread_cond_t condition;
pthread_barrier_t barrier; /* Ensures correct startup sequence */
int shutdown_thread;
int transfer_loop_finished;
struct libusb_transfer *transfer;
/* List of received input reports. */
struct input_report *input_reports;
/* Was kernel driver detached by libusb */
#ifdef DETACH_KERNEL_DRIVER
int is_driver_detached;
#endif
};
static struct hid_api_version api_version = {
.major = HID_API_VERSION_MAJOR,
.minor = HID_API_VERSION_MINOR,
.patch = HID_API_VERSION_PATCH
};
static libusb_context *usb_context = NULL;
uint16_t get_usb_code_for_current_locale(void);
static int return_data(hid_device *dev, unsigned char *data, size_t length);
static hid_device *new_hid_device(void)
{
hid_device *dev = (hid_device*) calloc(1, sizeof(hid_device));
dev->blocking = 1;
pthread_mutex_init(&dev->mutex, NULL);
pthread_cond_init(&dev->condition, NULL);
pthread_barrier_init(&dev->barrier, NULL, 2);
return dev;
}
static void free_hid_device(hid_device *dev)
{
/* Clean up the thread objects */
pthread_barrier_destroy(&dev->barrier);
pthread_cond_destroy(&dev->condition);
pthread_mutex_destroy(&dev->mutex);
hid_free_enumeration(dev->device_info);
/* Free the device itself */
free(dev);
}
#if 0
/*TODO: Implement this function on hidapi/libusb.. */
static void register_error(hid_device *dev, const char *op)
{
}
#endif
/* Get bytes from a HID Report Descriptor.
Only call with a num_bytes of 0, 1, 2, or 4. */
static uint32_t get_bytes(uint8_t *rpt, size_t len, size_t num_bytes, size_t cur)
{
/* Return if there aren't enough bytes. */
if (cur + num_bytes >= len)
return 0;
if (num_bytes == 0)
return 0;
else if (num_bytes == 1) {
return rpt[cur+1];
}
else if (num_bytes == 2) {
return (rpt[cur+2] * 256 + rpt[cur+1]);
}
else if (num_bytes == 4) {
return (rpt[cur+4] * 0x01000000 +
rpt[cur+3] * 0x00010000 +
rpt[cur+2] * 0x00000100 +
rpt[cur+1] * 0x00000001);
}
else
return 0;
}
/* Retrieves the device's Usage Page and Usage from the report
descriptor. The algorithm is simple, as it just returns the first
Usage and Usage Page that it finds in the descriptor.
The return value is 0 on success and -1 on failure. */
static int get_usage(uint8_t *report_descriptor, size_t size,
unsigned short *usage_page, unsigned short *usage)
{
unsigned int i = 0;
int size_code;
int data_len, key_size;
int usage_found = 0, usage_page_found = 0;
while (i < size) {
int key = report_descriptor[i];
int key_cmd = key & 0xfc;
//printf("key: %02hhx\n", key);
if ((key & 0xf0) == 0xf0) {
/* This is a Long Item. The next byte contains the
length of the data section (value) for this key.
See the HID specification, version 1.11, section
6.2.2.3, titled "Long Items." */
if (i+1 < size)
data_len = report_descriptor[i+1];
else
data_len = 0; /* malformed report */
key_size = 3;
}
else {
/* This is a Short Item. The bottom two bits of the
key contain the size code for the data section
(value) for this key. Refer to the HID
specification, version 1.11, section 6.2.2.2,
titled "Short Items." */
size_code = key & 0x3;
switch (size_code) {
case 0:
case 1:
case 2:
data_len = size_code;
break;
case 3:
data_len = 4;
break;
default:
/* Can't ever happen since size_code is & 0x3 */
data_len = 0;
break;
};
key_size = 1;
}
if (key_cmd == 0x4) {
*usage_page = get_bytes(report_descriptor, size, data_len, i);
usage_page_found = 1;
//printf("Usage Page: %x\n", (uint32_t)*usage_page);
}
if (key_cmd == 0x8) {
*usage = get_bytes(report_descriptor, size, data_len, i);
usage_found = 1;
//printf("Usage: %x\n", (uint32_t)*usage);
}
if (usage_page_found && usage_found)
return 0; /* success */
/* Skip over this key and it's associated data */
i += data_len + key_size;
}
return -1; /* failure */
}
#if defined(__FreeBSD__) && __FreeBSD__ < 10
/* The libusb version included in FreeBSD < 10 doesn't have this function. In
mainline libusb, it's inlined in libusb.h. This function will bear a striking
resemblance to that one, because there's about one way to code it.
Note that the data parameter is Unicode in UTF-16LE encoding.
Return value is the number of bytes in data, or LIBUSB_ERROR_*.
*/
static inline int libusb_get_string_descriptor(libusb_device_handle *dev,
uint8_t descriptor_index, uint16_t lang_id,
unsigned char *data, int length)
{
return libusb_control_transfer(dev,
LIBUSB_ENDPOINT_IN | 0x0, /* Endpoint 0 IN */
LIBUSB_REQUEST_GET_DESCRIPTOR,
(LIBUSB_DT_STRING << 8) | descriptor_index,
lang_id, data, (uint16_t) length, 1000);
}
#endif
/* Get the first language the device says it reports. This comes from
USB string #0. */
static uint16_t get_first_language(libusb_device_handle *dev)
{
uint16_t buf[32];
int len;
/* Get the string from libusb. */
len = libusb_get_string_descriptor(dev,
0x0, /* String ID */
0x0, /* Language */
(unsigned char*)buf,
sizeof(buf));
if (len < 4)
return 0x0;
return buf[1]; /* First two bytes are len and descriptor type. */
}
static int is_language_supported(libusb_device_handle *dev, uint16_t lang)
{
uint16_t buf[32];
int len;
int i;
/* Get the string from libusb. */
len = libusb_get_string_descriptor(dev,
0x0, /* String ID */
0x0, /* Language */
(unsigned char*)buf,
sizeof(buf));
if (len < 4)
return 0x0;
len /= 2; /* language IDs are two-bytes each. */
/* Start at index 1 because there are two bytes of protocol data. */
for (i = 1; i < len; i++) {
if (buf[i] == lang)
return 1;
}
return 0;
}
/* This function returns a newly allocated wide string containing the USB
device string numbered by the index. The returned string must be freed
by using free(). */
static wchar_t *get_usb_string(libusb_device_handle *dev, uint8_t idx)
{
char buf[512];
int len;
wchar_t *str = NULL;
#if !defined(__ANDROID__) && !defined(NO_ICONV) /* we don't use iconv on Android, or when it is explicitly disabled */
wchar_t wbuf[256];
/* iconv variables */
iconv_t ic;
size_t inbytes;
size_t outbytes;
size_t res;
ICONV_CONST char *inptr;
char *outptr;
#endif
/* Determine which language to use. */
uint16_t lang;
lang = get_usb_code_for_current_locale();
if (!is_language_supported(dev, lang))
lang = get_first_language(dev);
/* Get the string from libusb. */
len = libusb_get_string_descriptor(dev,
idx,
lang,
(unsigned char*)buf,
sizeof(buf));
if (len < 2) /* we always skip first 2 bytes */
return NULL;
#if defined(__ANDROID__) || defined(NO_ICONV)
/* Bionic does not have iconv support nor wcsdup() function, so it
has to be done manually. The following code will only work for
code points that can be represented as a single UTF-16 character,
and will incorrectly convert any code points which require more
than one UTF-16 character.
Skip over the first character (2-bytes). */
len -= 2;
str = (wchar_t*) malloc((len / 2 + 1) * sizeof(wchar_t));
int i;
for (i = 0; i < len / 2; i++) {
str[i] = buf[i * 2 + 2] | (buf[i * 2 + 3] << 8);
}
str[len / 2] = 0x00000000;
#else
/* buf does not need to be explicitly NULL-terminated because
it is only passed into iconv() which does not need it. */
/* Initialize iconv. */
ic = iconv_open("WCHAR_T", "UTF-16LE");
if (ic == (iconv_t)-1) {
LOG("iconv_open() failed\n");
return NULL;
}
/* Convert to native wchar_t (UTF-32 on glibc/BSD systems).
Skip the first character (2-bytes). */
inptr = buf+2;
inbytes = len-2;
outptr = (char*) wbuf;
outbytes = sizeof(wbuf);
res = iconv(ic, &inptr, &inbytes, &outptr, &outbytes);
if (res == (size_t)-1) {
LOG("iconv() failed\n");
goto err;
}
/* Write the terminating NULL. */
wbuf[sizeof(wbuf)/sizeof(wbuf[0])-1] = 0x00000000;
if (outbytes >= sizeof(wbuf[0]))
*((wchar_t*)outptr) = 0x00000000;
/* Allocate and copy the string. */
str = wcsdup(wbuf);
err:
iconv_close(ic);
#endif
return str;
}
/**
Max length of the result: "000-000.000.000.000.000.000.000:000.000" (39 chars).
64 is used for simplicity/alignment.
*/
static void get_path(char (*result)[64], libusb_device *dev, int config_number, int interface_number)
{
char *str = *result;
/* Note that USB3 port count limit is 7; use 8 here for alignment */
uint8_t port_numbers[8] = {0, 0, 0, 0, 0, 0, 0, 0};
int num_ports = libusb_get_port_numbers(dev, port_numbers, 8);
if (num_ports > 0) {
int n = snprintf(str, sizeof("000-000"), "%u-%u", libusb_get_bus_number(dev), port_numbers[0]);
for (uint8_t i = 1; i < num_ports; i++) {
n += snprintf(&str[n], sizeof(".000"), ".%u", port_numbers[i]);
}
n += snprintf(&str[n], sizeof(":000.000"), ":%u.%u", (uint8_t)config_number, (uint8_t)interface_number);
str[n] = '\0';
} else {
/* Likely impossible, but check: USB3.0 specs limit number of ports to 7 and buffer size here is 8 */
if (num_ports == LIBUSB_ERROR_OVERFLOW) {
LOG("make_path() failed. buffer overflow error\n");
} else {
LOG("make_path() failed. unknown error\n");
}
str[0] = '\0';
}
}
static char *make_path(libusb_device *dev, int config_number, int interface_number)
{
char str[64];
get_path(&str, dev, config_number, interface_number);
return strdup(str);
}
HID_API_EXPORT const struct hid_api_version* HID_API_CALL hid_version(void)
{
return &api_version;
}
HID_API_EXPORT const char* HID_API_CALL hid_version_str(void)
{
return HID_API_VERSION_STR;
}
int HID_API_EXPORT hid_init(void)
{
if (!usb_context) {
const char *locale;
/* Init Libusb */
if (libusb_init(&usb_context))
return -1;
/* Set the locale if it's not set. */
locale = setlocale(LC_CTYPE, NULL);
if (!locale)
setlocale(LC_CTYPE, "");
}
return 0;
}
int HID_API_EXPORT hid_exit(void)
{
if (usb_context) {
libusb_exit(usb_context);
usb_context = NULL;
}
return 0;
}
static int hid_get_report_descriptor_libusb(libusb_device_handle *handle, int interface_num, uint16_t expected_report_descriptor_size, unsigned char *buf, size_t buf_size)
{
unsigned char tmp[HID_API_MAX_REPORT_DESCRIPTOR_SIZE];
if (expected_report_descriptor_size > HID_API_MAX_REPORT_DESCRIPTOR_SIZE)
expected_report_descriptor_size = HID_API_MAX_REPORT_DESCRIPTOR_SIZE;
/* Get the HID Report Descriptor.
See USB HID Specificatin, sectin 7.1.1
*/
int res = libusb_control_transfer(handle, LIBUSB_ENDPOINT_IN|LIBUSB_RECIPIENT_INTERFACE, LIBUSB_REQUEST_GET_DESCRIPTOR, (LIBUSB_DT_REPORT << 8), interface_num, tmp, expected_report_descriptor_size, 5000);
if (res < 0) {
LOG("libusb_control_transfer() for getting the HID Report descriptor failed with %d: %s\n", res, libusb_error_name(res));
return -1;
}
if (res > (int)buf_size)
res = (int)buf_size;
memcpy(buf, tmp, (size_t)res);
return res;
}
/**
* Requires an opened device with *claimed interface*.
*/
static void fill_device_info_usage(struct hid_device_info *cur_dev, libusb_device_handle *handle, int interface_num, uint16_t expected_report_descriptor_size)
{
unsigned char hid_report_descriptor[HID_API_MAX_REPORT_DESCRIPTOR_SIZE];
unsigned short page = 0, usage = 0;
int res = hid_get_report_descriptor_libusb(handle, interface_num, expected_report_descriptor_size, hid_report_descriptor, sizeof(hid_report_descriptor));
if (res >= 0) {
/* Parse the usage and usage page
out of the report descriptor. */
get_usage(hid_report_descriptor, res, &page, &usage);
}
cur_dev->usage_page = page;
cur_dev->usage = usage;
}
#ifdef INVASIVE_GET_USAGE
static void invasive_fill_device_info_usage(struct hid_device_info *cur_dev, libusb_device_handle *handle, int interface_num, uint16_t report_descriptor_size)
{
int res = 0;
#ifdef DETACH_KERNEL_DRIVER
int detached = 0;
/* Usage Page and Usage */
res = libusb_kernel_driver_active(handle, interface_num);
if (res == 1) {
res = libusb_detach_kernel_driver(handle, interface_num);
if (res < 0)
LOG("Couldn't detach kernel driver, even though a kernel driver was attached.\n");
else
detached = 1;
}
#endif
res = libusb_claim_interface(handle, interface_num);
if (res >= 0) {
fill_device_info_usage(cur_dev, handle, interface_num, report_descriptor_size);
/* Release the interface */
res = libusb_release_interface(handle, interface_num);
if (res < 0)
LOG("Can't release the interface.\n");
}
else
LOG("Can't claim interface: (%d) %s\n", res, libusb_error_name(res));
#ifdef DETACH_KERNEL_DRIVER
/* Re-attach kernel driver if necessary. */
if (detached) {
res = libusb_attach_kernel_driver(handle, interface_num);
if (res < 0)
LOG("Couldn't re-attach kernel driver.\n");
}
#endif
}
#endif /* INVASIVE_GET_USAGE */
/**
* Create and fill up most of hid_device_info fields.
* usage_page/usage is not filled up.
*/
static struct hid_device_info * create_device_info_for_device(libusb_device *device, libusb_device_handle *handle, struct libusb_device_descriptor *desc, int config_number, int interface_num)
{
struct hid_device_info *cur_dev = calloc(1, sizeof(struct hid_device_info));
if (cur_dev == NULL) {
return NULL;
}
/* VID/PID */
cur_dev->vendor_id = desc->idVendor;
cur_dev->product_id = desc->idProduct;
cur_dev->release_number = desc->bcdDevice;
cur_dev->interface_number = interface_num;
cur_dev->bus_type = HID_API_BUS_USB;
cur_dev->path = make_path(device, config_number, interface_num);
if (!handle) {
return cur_dev;
}
if (desc->iSerialNumber > 0)
cur_dev->serial_number = get_usb_string(handle, desc->iSerialNumber);
/* Manufacturer and Product strings */
if (desc->iManufacturer > 0)
cur_dev->manufacturer_string = get_usb_string(handle, desc->iManufacturer);
if (desc->iProduct > 0)
cur_dev->product_string = get_usb_string(handle, desc->iProduct);
return cur_dev;
}
static uint16_t get_report_descriptor_size_from_interface_descriptors(const struct libusb_interface_descriptor *intf_desc)
{
int i = 0;
int found_hid_report_descriptor = 0;
uint16_t result = HID_API_MAX_REPORT_DESCRIPTOR_SIZE;
const unsigned char *extra = intf_desc->extra;
int extra_length = intf_desc->extra_length;
/*
"extra" contains a HID descriptor
See section 6.2.1 of HID 1.1 specification.
*/
while (extra_length >= 2) { /* Descriptor header: bLength/bDescriptorType */
if (extra[1] == LIBUSB_DT_HID) { /* bDescriptorType */
if (extra_length < 6) {
LOG("Broken HID descriptor: not enough data\n");
break;
}
unsigned char bNumDescriptors = extra[5];
if (extra_length < (6 + 3 * bNumDescriptors)) {
LOG("Broken HID descriptor: not enough data for Report metadata\n");
break;
}
for (i = 0; i < bNumDescriptors; i++) {
if (extra[6 + 3 * i] == LIBUSB_DT_REPORT) {
result = (uint16_t)extra[6 + 3 * i + 2] << 8 | extra[6 + 3 * i + 1];
found_hid_report_descriptor = 1;
break;
}
}
if (!found_hid_report_descriptor) {
/* We expect to find exactly 1 HID descriptor (LIBUSB_DT_HID)
which should contain exactly one HID Report Descriptor metadata (LIBUSB_DT_REPORT). */
LOG("Broken HID descriptor: missing Report descriptor\n");
}
break;
}
if (extra[0] == 0) { /* bLength */
LOG("Broken HID Interface descriptors: zero-sized descriptor\n");
break;
}
/* Iterate over to the next Descriptor */
extra_length -= extra[0];
extra += extra[0];
}
return result;
}
struct hid_device_info HID_API_EXPORT *hid_enumerate(unsigned short vendor_id, unsigned short product_id)
{
libusb_device **devs;
libusb_device *dev;
libusb_device_handle *handle = NULL;
ssize_t num_devs;
int i = 0;
struct hid_device_info *root = NULL; /* return object */
struct hid_device_info *cur_dev = NULL;
if(hid_init() < 0)
return NULL;
num_devs = libusb_get_device_list(usb_context, &devs);
if (num_devs < 0)
return NULL;
while ((dev = devs[i++]) != NULL) {
struct libusb_device_descriptor desc;
struct libusb_config_descriptor *conf_desc = NULL;
int j, k;
int res = libusb_get_device_descriptor(dev, &desc);
unsigned short dev_vid = desc.idVendor;
unsigned short dev_pid = desc.idProduct;
if ((vendor_id != 0x0 && vendor_id != dev_vid) ||
(product_id != 0x0 && product_id != dev_pid)) {
continue;
}
res = libusb_get_active_config_descriptor(dev, &conf_desc);
if (res < 0)
libusb_get_config_descriptor(dev, 0, &conf_desc);
if (conf_desc) {
for (j = 0; j < conf_desc->bNumInterfaces; j++) {
const struct libusb_interface *intf = &conf_desc->interface[j];
for (k = 0; k < intf->num_altsetting; k++) {
const struct libusb_interface_descriptor *intf_desc;
intf_desc = &intf->altsetting[k];
if (intf_desc->bInterfaceClass == LIBUSB_CLASS_HID) {
struct hid_device_info *tmp;
res = libusb_open(dev, &handle);
#ifdef __ANDROID__
if (handle) {
/* There is (a potential) libusb Android backend, in which
device descriptor is not accurate up until the device is opened.
https://github.com/libusb/libusb/pull/874#discussion_r632801373
A workaround is to re-read the descriptor again.
Even if it is not going to be accepted into libusb master,
having it here won't do any harm, since reading the device descriptor
is as cheap as copy 18 bytes of data. */
libusb_get_device_descriptor(dev, &desc);
}
#endif
tmp = create_device_info_for_device(dev, handle, &desc, conf_desc->bConfigurationValue, intf_desc->bInterfaceNumber);
if (tmp) {
#ifdef INVASIVE_GET_USAGE
/* TODO: have a runtime check for this section. */
/*
This section is removed because it is too
invasive on the system. Getting a Usage Page
and Usage requires parsing the HID Report
descriptor. Getting a HID Report descriptor
involves claiming the interface. Claiming the
interface involves detaching the kernel driver.
Detaching the kernel driver is hard on the system
because it will unclaim interfaces (if another
app has them claimed) and the re-attachment of
the driver will sometimes change /dev entry names.
It is for these reasons that this section is
optional. For composite devices, use the interface
field in the hid_device_info struct to distinguish
between interfaces. */
if (handle) {
uint16_t report_descriptor_size = get_report_descriptor_size_from_interface_descriptors(intf_desc);
invasive_fill_device_info_usage(tmp, handle, intf_desc->bInterfaceNumber, report_descriptor_size);
}
#endif /* INVASIVE_GET_USAGE */
if (cur_dev) {
cur_dev->next = tmp;
}
else {
root = tmp;
}
cur_dev = tmp;
}
if (res >= 0) {
libusb_close(handle);
handle = NULL;
}
}
} /* altsettings */
} /* interfaces */
libusb_free_config_descriptor(conf_desc);
}
}
libusb_free_device_list(devs, 1);
return root;
}
void HID_API_EXPORT hid_free_enumeration(struct hid_device_info *devs)
{
struct hid_device_info *d = devs;
while (d) {
struct hid_device_info *next = d->next;
free(d->path);
free(d->serial_number);
free(d->manufacturer_string);
free(d->product_string);
free(d);
d = next;
}
}
hid_device * hid_open(unsigned short vendor_id, unsigned short product_id, const wchar_t *serial_number)
{
struct hid_device_info *devs, *cur_dev;
const char *path_to_open = NULL;
hid_device *handle = NULL;
devs = hid_enumerate(vendor_id, product_id);
cur_dev = devs;
while (cur_dev) {
if (cur_dev->vendor_id == vendor_id &&
cur_dev->product_id == product_id) {
if (serial_number) {
if (cur_dev->serial_number &&
wcscmp(serial_number, cur_dev->serial_number) == 0) {
path_to_open = cur_dev->path;
break;
}
}
else {
path_to_open = cur_dev->path;
break;
}
}
cur_dev = cur_dev->next;
}
if (path_to_open) {
/* Open the device */
handle = hid_open_path(path_to_open);
}
hid_free_enumeration(devs);
return handle;
}
static void read_callback(struct libusb_transfer *transfer)
{
hid_device *dev = transfer->user_data;
int res;
if (transfer->status == LIBUSB_TRANSFER_COMPLETED) {
struct input_report *rpt = (struct input_report*) malloc(sizeof(*rpt));
rpt->data = (uint8_t*) malloc(transfer->actual_length);
memcpy(rpt->data, transfer->buffer, transfer->actual_length);
rpt->len = transfer->actual_length;
rpt->next = NULL;
pthread_mutex_lock(&dev->mutex);
/* Attach the new report object to the end of the list. */
if (dev->input_reports == NULL) {
/* The list is empty. Put it at the root. */
dev->input_reports = rpt;
pthread_cond_signal(&dev->condition);
}
else {
/* Find the end of the list and attach. */
struct input_report *cur = dev->input_reports;
int num_queued = 0;
while (cur->next != NULL) {
cur = cur->next;
num_queued++;
}
cur->next = rpt;
/* Pop one off if we've reached 30 in the queue. This
way we don't grow forever if the user never reads
anything from the device. */
if (num_queued > 30) {
return_data(dev, NULL, 0);
}
}
pthread_mutex_unlock(&dev->mutex);
}
else if (transfer->status == LIBUSB_TRANSFER_CANCELLED) {
dev->shutdown_thread = 1;
}
else if (transfer->status == LIBUSB_TRANSFER_NO_DEVICE) {
dev->shutdown_thread = 1;
}
else if (transfer->status == LIBUSB_TRANSFER_TIMED_OUT) {
//LOG("Timeout (normal)\n");
}
else {
LOG("Unknown transfer code: %d\n", transfer->status);
}
if (dev->shutdown_thread) {
dev->transfer_loop_finished = 1;
return;
}
/* Re-submit the transfer object. */
res = libusb_submit_transfer(transfer);
if (res != 0) {
LOG("Unable to submit URB: (%d) %s\n", res, libusb_error_name(res));
dev->shutdown_thread = 1;
dev->transfer_loop_finished = 1;
}
}
static void *read_thread(void *param)
{
int res;
hid_device *dev = param;
uint8_t *buf;
const size_t length = dev->input_ep_max_packet_size;
/* Set up the transfer object. */
buf = (uint8_t*) malloc(length);
dev->transfer = libusb_alloc_transfer(0);
libusb_fill_interrupt_transfer(dev->transfer,
dev->device_handle,
dev->input_endpoint,
buf,
length,
read_callback,
dev,
5000/*timeout*/);
/* Make the first submission. Further submissions are made
from inside read_callback() */
res = libusb_submit_transfer(dev->transfer);
if(res < 0) {
LOG("libusb_submit_transfer failed: %d %s. Stopping read_thread from running\n", res, libusb_error_name(res));
dev->shutdown_thread = 1;
dev->transfer_loop_finished = 1;
}
/* Notify the main thread that the read thread is up and running. */
pthread_barrier_wait(&dev->barrier);