Initial commit

src/hid_linux.rs

@@ -0,0 +1,86 @@
+// This file is part of ctap, a Rust implementation of the FIDO2 protocol.
+// Copyright (c) Ariën Holthuizen <contact@ardaxi.com>
+// Licensed under the Apache License, Version 2.0, <LICENSE-APACHE or
+// http://apache.org/licenses/LICENSE-2.0> or the MIT license <LICENSE-MIT or
+// http://opensource.org/licenses/MIT>, at your option. This file may not be
+// copied, modified, or distributed except according to those terms.
+use std::io;
+use std::fs;
+use std::path::PathBuf;
+use byteorder::{ByteOrder, LittleEndian};
+pub use super::hid_common::*;
+
+static REPORT_DESCRIPTOR_KEY_MASK: u8 = 0xfc;
+static LONG_ITEM_ENCODING: u8 = 0xfe;
+static USAGE_PAGE: u8 = 0x04;
+static USAGE: u8 = 0x08;
+static REPORT_SIZE: u8 = 0x74;
+
+pub fn enumerate() -> io::Result<Vec<DeviceInfo>> {
+    fs::read_dir("/sys/class/hidraw")?
+        .filter_map(|entry| entry.ok())
+        .map(|entry| path_to_device(&entry.path()))
+        .collect()
+}
+
+fn path_to_device(path: &PathBuf) -> io::Result<DeviceInfo> {
+    let mut rd_path = path.clone();
+    rd_path.push("device/report_descriptor");
+    let rd = fs::read(rd_path)?;
+    let mut usage_page: u16 = 0;
+    let mut usage: u16 = 0;
+    let mut report_size: u16 = 0;
+    let mut pos: usize = 0;
+
+    while pos < rd.len() {
+        let key = rd[pos];
+        let mut key_size: usize = 1;
+        let mut size: u8;
+
+        if key == LONG_ITEM_ENCODING {
+            key_size = 3;
+            size = rd[pos + 1];
+        } else {
+            size = key & 0x03;
+
+            if size == 0x03 {
+                size = 0x04
+            }
+        }
+
+        if key & REPORT_DESCRIPTOR_KEY_MASK == USAGE_PAGE {
+            if size != 2 {
+                usage_page = u16::from(rd[pos + 1])
+            } else {
+                usage_page = LittleEndian::read_u16(&rd[(pos + 1)..(pos + 1 + (size as usize))]);
+            }
+        }
+
+        if key & REPORT_DESCRIPTOR_KEY_MASK == USAGE {
+            if size != 2 {
+                usage = u16::from(rd[pos + 1])
+            } else {
+                usage = LittleEndian::read_u16(&rd[(pos + 1)..(pos + 1 + (size as usize))]);
+            }
+        }
+
+        if key & REPORT_DESCRIPTOR_KEY_MASK == REPORT_SIZE {
+            if size != 2 {
+                report_size = u16::from(rd[pos + 1])
+            } else {
+                report_size = LittleEndian::read_u16(&rd[(pos + 1)..(pos + 1 + (size as usize))]);
+            }
+        }
+
+        pos = pos + key_size + size as usize;
+    }
+
+    let mut device_path = PathBuf::from("/dev");
+    device_path.push(path.file_name().unwrap());
+
+    Ok(DeviceInfo {
+        path: device_path,
+        usage_page,
+        usage,
+    })
+}