Skip to content

libusb backend: stabilize device path, superseeds: #117 #291

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 1 commit into from
Jul 3, 2021
Merged

libusb backend: stabilize device path, superseeds: #117 #291

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
34 changes: 24 additions & 10 deletions libusb/hid.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -484,15 +484,29 @@ static wchar_t *get_usb_string(libusb_device_handle *dev, uint8_t idx)
return str;
}

static char *make_path(libusb_device *dev, int interface_number)
static char *make_path(libusb_device *dev, int interface_number, int config_number)
{
char str[64];
snprintf(str, sizeof(str), "%04x:%04x:%02x",
libusb_get_bus_number(dev),
libusb_get_device_address(dev),
interface_number);
str[sizeof(str)-1] = '\0';

char str[64]; /* max length "000-000.000.000.000.000.000.000:000.000" */
/* 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 {
/* 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';
}
return strdup(str);
}

Expand Down Expand Up @@ -590,7 +604,7 @@ struct hid_device_info HID_API_EXPORT *hid_enumerate(unsigned short vendor_id,

/* Fill out the record */
cur_dev->next = NULL;
cur_dev->path = make_path(dev, interface_num);
cur_dev->path = make_path(dev, interface_num, conf_desc->bConfigurationValue);

res = libusb_open(dev, &handle);

Expand Down Expand Up @@ -926,7 +940,7 @@ hid_device * HID_API_EXPORT hid_open_path(const char *path)
const struct libusb_interface_descriptor *intf_desc;
intf_desc = &intf->altsetting[k];
if (intf_desc->bInterfaceClass == LIBUSB_CLASS_HID) {
char *dev_path = make_path(usb_dev, intf_desc->bInterfaceNumber);
char *dev_path = make_path(usb_dev, intf_desc->bInterfaceNumber, conf_desc->bConfigurationValue);
if (!strcmp(dev_path, path)) {
/* Matched Paths. Open this device */

Expand Down