drivers/libusb0.c: libusb_open(): try to re-fetch curDevice->Vendor, …

…Product, Serial if NULL, after claiming it by other criteria [networkupstools#2562]

Signed-off-by: Jim Klimov <[email protected]>

drivers/libusb0.c

@@ -542,6 +542,58 @@ static int libusb_open(usb_dev_handle **udevp,
 
 			nut_usb_set_altinterface(udev);
 
+			/* If libusb failed to identify the device strings earlier,
+			 * can we do that after claiming the interface? Just try...
+			 * Note that we succeeded so far, meaning these strings were
+			 * not among matching criteria. But they can be important for
+			 * our drivers (e.g. per-model tweaks) and pretty reporting
+			 * of certain `device.*` and/or `ups.*` data points.
+			 */
+			if (!curDevice->Vendor) {
+				retries = MAX_RETRY;
+				while (retries > 0) {
+					ret = usb_get_string_simple(udev, dev->descriptor.iManufacturer,
+						string, sizeof(string));
+					if (ret > 0) {
+						curDevice->Vendor = xstrdup(string);
+						break;
+					}
+					retries--;
+					upsdebugx(1, "%s get iManufacturer failed, retrying...", __func__);
+				}
+				upsdebugx(2, "- Manufacturer: %s", curDevice->Vendor ? curDevice->Vendor : "unknown");
+			}
+
+			if (!curDevice->Product) {
+				retries = MAX_RETRY;
+				while (retries > 0) {
+					ret = usb_get_string_simple(udev, dev->descriptor.iProduct,
+						string, sizeof(string));
+					if (ret > 0) {
+						curDevice->Product = xstrdup(string);
+						break;
+					}
+					retries--;
+					upsdebugx(1, "%s get iProduct failed, retrying...", __func__);
+				}
+				upsdebugx(2, "- Product: %s", curDevice->Product ? curDevice->Product : "unknown");
+			}
+
+			if (!curDevice->Serial) {
+				retries = MAX_RETRY;
+				while (retries > 0) {
+					ret = usb_get_string_simple(udev, dev->descriptor.iSerialNumber,
+						string, sizeof(string));
+					if (ret > 0) {
+						curDevice->Serial = xstrdup(string);
+						break;
+					}
+					retries--;
+					upsdebugx(1, "%s get iSerialNumber failed, retrying...", __func__);
+				}
+				upsdebugx(2, "- Serial Number: %s", curDevice->Serial ? curDevice->Serial : "unknown");
+			}
+
 			/* Did the driver provide a callback method for any further
 			 * device acceptance checks (e.g. when same ID is supported
 			 * by several sub-drivers, differing by vendor/model strings)?