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windows: Use correct serial number for composite devices
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Fetch the serial number from the interface's parent device, as it
contains the correct serial number on its HWID.
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danielstuart14 committed Nov 27, 2023
1 parent 14ab9c9 commit 9c79b57
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Showing 2 changed files with 62 additions and 14 deletions.
4 changes: 3 additions & 1 deletion CHANGELOG.md
Original file line number Diff line number Diff line change
Expand Up @@ -17,7 +17,9 @@ project adheres to [Semantic Versioning](https://semver.org/).
[#130](https://github.com/serialport/serialport-rs/pull/130)

### Fixed

* Fixes a bug on Windows where composite devices would show a incorrect serial
number.
[#141](https://github.com/serialport/serialport-rs/pull/141)
* Fixes a bug on Linux without udev where `available_ports()` returned wrong
device file paths.
[#122](https://github.com/serialport/serialport-rs/pull/122)
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72 changes: 59 additions & 13 deletions src/windows/enumerate.rs
Original file line number Diff line number Diff line change
Expand Up @@ -5,6 +5,7 @@ use regex::Regex;
use winapi::shared::guiddef::*;
use winapi::shared::minwindef::*;
use winapi::shared::winerror::*;
use winapi::um::cfgmgr32::*;
use winapi::um::cguid::GUID_NULL;
use winapi::um::errhandlingapi::GetLastError;
use winapi::um::setupapi::*;
Expand Down Expand Up @@ -83,22 +84,33 @@ fn get_ports_guids() -> Result<Vec<GUID>> {
/// information if the hardware ID can be parsed correctly. The manufacturer
/// and product names cannot be determined from the HWID string, so those are
/// set as None.
///
/// For composite USB devices, the HWID string will be for the interface. In
/// this case, the parent HWID string must be provided so that the correct
/// serial number can be determined.
///
/// Some HWID examples are:
/// - MicroPython pyboard: USB\VID_F055&PID_9802\385435603432
/// - BlackMagic GDB Server: USB\VID_1D50&PID_6018&MI_00\6&A694CA9&0&0000
/// - BlackMagic UART port: USB\VID_1D50&PID_6018&MI_02\6&A694CA9&0&0002
/// - FTDI Serial Adapter: FTDIBUS\VID_0403+PID_6001+A702TB52A\0000
fn parse_usb_port_info(hardware_id: &str) -> Option<UsbPortInfo> {
fn parse_usb_port_info(hardware_id: &str, parent_hardware_id: Option<&str>) -> Option<UsbPortInfo> {
let re = Regex::new(concat!(
r"VID_(?P<vid>[[:xdigit:]]{4})",
r"[&+]PID_(?P<pid>[[:xdigit:]]{4})",
r"(?:[&+]MI_(?P<iid>[[:xdigit:]]{2})){0,1}",
r"([\\+](?P<serial>[\w&]+))?"
r"([\\+](?P<serial>\w+))?"
))
.unwrap();

let caps = re.captures(hardware_id)?;
let mut caps = re.captures(hardware_id)?;

let interface = caps.name("iid").and_then(|m| u8::from_str_radix(m.as_str(), 16).ok());

if let Some(_) = interface {
// If this is a composite device, we need to parse the parent's HWID to get the correct information.
caps = re.captures(parent_hardware_id?)?;
}

Some(UsbPortInfo {
vid: u16::from_str_radix(&caps[1], 16).ok()?,
Expand All @@ -114,9 +126,7 @@ fn parse_usb_port_info(hardware_id: &str) -> Option<UsbPortInfo> {
manufacturer: None,
product: None,
#[cfg(feature = "usbportinfo-interface")]
interface: caps
.name("iid")
.and_then(|m| u8::from_str_radix(m.as_str(), 16).ok()),
interface: interface,
})
}

Expand Down Expand Up @@ -183,6 +193,41 @@ struct PortDevice {
}

impl PortDevice {
// Retrieves the device instance id string associated with this device's parent.
// This is useful for determining the serial number of a composite USB device.
fn parent_instance_id(&mut self) -> Option<String> {
let mut result_buf = [0i8; MAX_PATH];
let mut parent_device_instance_id = 0;

let res = unsafe {
CM_Get_Parent(&mut parent_device_instance_id, self.devinfo_data.DevInst, 0)
};
if res == CR_SUCCESS {
let res = unsafe {
CM_Get_Device_IDA(
parent_device_instance_id,
result_buf.as_mut_ptr(),
(result_buf.len() - 1) as ULONG,
0,
)
};

if res == CR_SUCCESS {
let end_of_buffer = result_buf.len() - 1;
result_buf[end_of_buffer] = 0;
Some(unsafe {
CStr::from_ptr(result_buf.as_ptr())
.to_string_lossy()
.into_owned()
})
} else {
None
}
} else {
None
}
}

// Retrieves the device instance id string associated with this device. Some examples of
// instance id strings are:
// MicroPython Board: USB\VID_F055&PID_9802\385435603432
Expand Down Expand Up @@ -254,8 +299,9 @@ impl PortDevice {
// Determines the port_type for this device, and if it's a USB port populate the various fields.
pub fn port_type(&mut self) -> SerialPortType {
self.instance_id()
.and_then(|s| parse_usb_port_info(&s))
.map(|mut info| {
.map(|s| (s, self.parent_instance_id())) // Get parent instance id if it exists.
.and_then(|(d, p)| parse_usb_port_info(&d, p.as_deref()))
.map(|mut info: UsbPortInfo| {
info.manufacturer = self.property(SPDRP_MFG);
info.product = self.property(SPDRP_FRIENDLYNAME);
SerialPortType::UsbPort(info)
Expand Down Expand Up @@ -326,17 +372,17 @@ pub fn available_ports() -> Result<Vec<SerialPortInfo>> {
#[test]
fn test_parsing_usb_port_information() {
let bm_uart_hwid = r"USB\VID_1D50&PID_6018&MI_02\6&A694CA9&0&0000";
let info = parse_usb_port_info(bm_uart_hwid).unwrap();
let bm_parent_hwid = r"USB\VID_1D50&PID_6018\85A12F01";
let info = parse_usb_port_info(bm_uart_hwid, Some(bm_parent_hwid)).unwrap();

assert_eq!(info.vid, 0x1D50);
assert_eq!(info.pid, 0x6018);
// FIXME: The 'serial number' as reported by the HWID likely needs some review
assert_eq!(info.serial_number, Some("A694CA9".to_string()));
assert_eq!(info.serial_number, Some("85A12F01".to_string()));
#[cfg(feature = "usbportinfo-interface")]
assert_eq!(info.interface, Some(2));

let ftdi_serial_hwid = r"FTDIBUS\VID_0403+PID_6001+A702TB52A\0000";
let info = parse_usb_port_info(ftdi_serial_hwid).unwrap();
let info = parse_usb_port_info(ftdi_serial_hwid, None).unwrap();

assert_eq!(info.vid, 0x0403);
assert_eq!(info.pid, 0x6001);
Expand All @@ -345,7 +391,7 @@ fn test_parsing_usb_port_information() {
assert_eq!(info.interface, None);

let pyboard_hwid = r"USB\VID_F055&PID_9802\385435603432";
let info = parse_usb_port_info(pyboard_hwid).unwrap();
let info = parse_usb_port_info(pyboard_hwid, None).unwrap();

assert_eq!(info.vid, 0xF055);
assert_eq!(info.pid, 0x9802);
Expand Down

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