diff --git a/src/hidapi/libusb/hid.c b/src/hidapi/libusb/hid.c index d6b73801c7..9bec8e2e83 100644 --- a/src/hidapi/libusb/hid.c +++ b/src/hidapi/libusb/hid.c @@ -259,8 +259,16 @@ static int get_usage(uint8_t *report_descriptor, size_t size, //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; + if (data_len == 4) { /* Usages 5.5 / Usage Page 6.2.2.7 */ + *usage_page = get_bytes(report_descriptor, size, 2, i + 2); + usage_page_found = 1; + *usage = get_bytes(report_descriptor, size, 2, i); + usage_found = 1; + } + else { + *usage = get_bytes(report_descriptor, size, data_len, i); + usage_found = 1; + } //printf("Usage: %x\n", (uint32_t)*usage); } diff --git a/src/hidapi/linux/hid.c b/src/hidapi/linux/hid.c index 50f85f3b3f..507a2b1f76 100644 --- a/src/hidapi/linux/hid.c +++ b/src/hidapi/linux/hid.c @@ -206,7 +206,7 @@ static wchar_t *copy_udev_string(struct udev_device *dev, const char *udev_name) * Returns 1 if successful, 0 if an invalid key * Sets data_len and key_size when successful */ -static int get_hid_item_size(__u8 *report_descriptor, unsigned int pos, __u32 size, int *data_len, int *key_size) +static int get_hid_item_size(const __u8 *report_descriptor, __u32 size, unsigned int pos, int *data_len, int *key_size) { int key = report_descriptor[pos]; int size_code; @@ -262,7 +262,7 @@ static int get_hid_item_size(__u8 *report_descriptor, unsigned int pos, __u32 si * Get bytes from a HID Report Descriptor. * Only call with a num_bytes of 0, 1, 2, or 4. */ -static __u32 get_hid_report_bytes(__u8 *rpt, size_t len, size_t num_bytes, size_t cur) +static __u32 get_hid_report_bytes(const __u8 *rpt, size_t len, size_t num_bytes, size_t cur) { /* Return if there aren't enough bytes. */ if (cur + num_bytes >= len) @@ -285,6 +285,60 @@ static __u32 get_hid_report_bytes(__u8 *rpt, size_t len, size_t num_bytes, size_ return 0; } +/* + * Iterates until the end of a Collection. + * Assumes that *pos is exactly at the beginning of a Collection. + * Skips all nested Collection, i.e. iterates until the end of current level Collection. + * + * The return value is non-0 when an end of current Collection is found, + * 0 when error is occured (broken Descriptor, end of a Collection is found before its begin, + * or no Collection is found at all). + */ +static int hid_iterate_over_collection(const __u8 *report_descriptor, __u32 size, unsigned int *pos, int *data_len, int *key_size) +{ + int collection_level = 0; + + while (*pos < size) { + int key = report_descriptor[*pos]; + int key_cmd = key & 0xfc; + + /* Determine data_len and key_size */ + if (!get_hid_item_size(report_descriptor, size, *pos, data_len, key_size)) + return 0; /* malformed report */ + + switch (key_cmd) { + case 0xa0: /* Collection 6.2.2.4 (Main) */ + collection_level++; + break; + case 0xc0: /* End Collection 6.2.2.4 (Main) */ + collection_level--; + break; + } + + if (collection_level < 0) { + /* Broken descriptor or someone is using this function wrong, + * i.e. should be called exactly at the collection start */ + return 0; + } + + if (collection_level == 0) { + /* Found it! + * Also possible when called not at the collection start, but should not happen if used correctly */ + return 1; + } + + *pos += *data_len + *key_size; + } + + return 0; /* Did not find the end of a Collection */ +} + +struct hid_usage_iterator { + unsigned int pos; + int usage_page_found; + unsigned short usage_page; +}; + /* * Retrieves the device's Usage Page and Usage from the report descriptor. * The algorithm returns the current Usage Page/Usage pair whenever a new @@ -302,63 +356,64 @@ static __u32 get_hid_report_bytes(__u8 *rpt, size_t len, size_t num_bytes, size_ * 1 when finished processing descriptor. * -1 on a malformed report. */ -static int get_next_hid_usage(__u8 *report_descriptor, __u32 size, unsigned int *pos, unsigned short *usage_page, unsigned short *usage) +static int get_next_hid_usage(const __u8 *report_descriptor, __u32 size, struct hid_usage_iterator *ctx, unsigned short *usage_page, unsigned short *usage) { int data_len, key_size; - int initial = *pos == 0; /* Used to handle case where no top-level application collection is defined */ - int usage_pair_ready = 0; + int initial = ctx->pos == 0; /* Used to handle case where no top-level application collection is defined */ - /* Usage is a Local Item, it must be set before each Main Item (Collection) before a pair is returned */ int usage_found = 0; - while (*pos < size) { - int key = report_descriptor[*pos]; + while (ctx->pos < size) { + int key = report_descriptor[ctx->pos]; int key_cmd = key & 0xfc; /* Determine data_len and key_size */ - if (!get_hid_item_size(report_descriptor, *pos, size, &data_len, &key_size)) + if (!get_hid_item_size(report_descriptor, size, ctx->pos, &data_len, &key_size)) return -1; /* malformed report */ switch (key_cmd) { case 0x4: /* Usage Page 6.2.2.7 (Global) */ - *usage_page = get_hid_report_bytes(report_descriptor, size, data_len, *pos); + ctx->usage_page = get_hid_report_bytes(report_descriptor, size, data_len, ctx->pos); + ctx->usage_page_found = 1; break; case 0x8: /* Usage 6.2.2.8 (Local) */ - *usage = get_hid_report_bytes(report_descriptor, size, data_len, *pos); - usage_found = 1; + if (data_len == 4) { /* Usages 5.5 / Usage Page 6.2.2.7 */ + ctx->usage_page = get_hid_report_bytes(report_descriptor, size, 2, ctx->pos + 2); + ctx->usage_page_found = 1; + *usage = get_hid_report_bytes(report_descriptor, size, 2, ctx->pos); + usage_found = 1; + } + else { + *usage = get_hid_report_bytes(report_descriptor, size, data_len, ctx->pos); + usage_found = 1; + } break; case 0xa0: /* Collection 6.2.2.4 (Main) */ - /* A Usage Item (Local) must be found for the pair to be valid */ - if (usage_found) - usage_pair_ready = 1; + if (!hid_iterate_over_collection(report_descriptor, size, &ctx->pos, &data_len, &key_size)) { + return -1; + } - /* Usage is a Local Item, unset it */ - usage_found = 0; - break; + /* A pair is valid - to be reported when Collection is found */ + if (usage_found && ctx->usage_page_found) { + *usage_page = ctx->usage_page; + return 0; + } - case 0x80: /* Input 6.2.2.4 (Main) */ - case 0x90: /* Output 6.2.2.4 (Main) */ - case 0xb0: /* Feature 6.2.2.4 (Main) */ - case 0xc0: /* End Collection 6.2.2.4 (Main) */ - /* Usage is a Local Item, unset it */ - usage_found = 0; break; } /* Skip over this key and its associated data */ - *pos += data_len + key_size; - - /* Return usage pair */ - if (usage_pair_ready) - return 0; + ctx->pos += data_len + key_size; } /* If no top-level application collection is found and usage page/usage pair is found, pair is valid https://docs.microsoft.com/en-us/windows-hardware/drivers/hid/top-level-collections */ - if (initial && usage_found) - return 0; /* success */ + if (initial && usage_found && ctx->usage_page_found) { + *usage_page = ctx->usage_page; + return 0; /* success */ + } return 1; /* finished processing */ } @@ -804,12 +859,14 @@ static struct hid_device_info * create_device_info_for_device(struct udev_device result = get_hid_report_descriptor_from_sysfs(sysfs_path, &report_desc); if (result >= 0) { unsigned short page = 0, usage = 0; - unsigned int pos = 0; + struct hid_usage_iterator usage_iterator; + memset(&usage_iterator, 0, sizeof(usage_iterator)); + /* * Parse the first usage and usage page * out of the report descriptor. */ - if (!get_next_hid_usage(report_desc.value, report_desc.size, &pos, &page, &usage)) { + if (!get_next_hid_usage(report_desc.value, report_desc.size, &usage_iterator, &page, &usage)) { cur_dev->usage_page = page; cur_dev->usage = usage; } @@ -818,7 +875,7 @@ static struct hid_device_info * create_device_info_for_device(struct udev_device * Parse any additional usage and usage pages * out of the report descriptor. */ - while (!get_next_hid_usage(report_desc.value, report_desc.size, &pos, &page, &usage)) { + while (!get_next_hid_usage(report_desc.value, report_desc.size, &usage_iterator, &page, &usage)) { /* Create new record for additional usage pairs */ struct hid_device_info *tmp = (struct hid_device_info*) calloc(1, sizeof(struct hid_device_info)); struct hid_device_info *prev_dev = cur_dev; @@ -980,9 +1037,10 @@ struct hid_device_info HID_API_EXPORT *hid_enumerate(unsigned short vendor_id, struct hidraw_report_descriptor report_desc; unsigned short page = 0, usage = 0; - unsigned int pos = 0; if (get_hid_report_descriptor_from_sysfs(sysfs_path, &report_desc) >= 0) { - get_next_hid_usage(report_desc.value, report_desc.size, &pos, &page, &usage); + struct hid_usage_iterator usage_iterator; + memset(&usage_iterator, 0, sizeof(usage_iterator)); + get_next_hid_usage(report_desc.value, report_desc.size, &usage_iterator, &page, &usage); } if (HIDAPI_IGNORE_DEVICE(bus_type, dev_vid, dev_pid, page, usage)) { continue;