2 files changed, 220 insertions, 0 deletions
diff --git a/dom/webauthn/libudev-sys/Cargo.toml b/dom/webauthn/libudev-sys/Cargo.toml
new file mode 100644
index 0000000000..b438a56927
--- /dev/null
+++ b/dom/webauthn/libudev-sys/Cargo.toml
@@ -0,0 +1,38 @@
+# This is a fork of libudev-sys that dynamically loads its symbols with
+# dlopen when they are first used. This continues a precedent established
+# by Firefox's gamepad APIs to minimize the footprint of features when they
+# aren't being used. Specifically, this avoids the cost of dynamically linking
+# in libudev at process startup.
+#
+# "-sys" crates are a convention in the rust ecosystem for "a simple header
+# for a C library that Rust code can use to build a richer and safer API on
+# top of". In this case, libudev-sys is used by the [libudev crate].
+#
+# As of this writing, this hack is being used by the [authenticator-rs] crate,
+# which uses the libudev crate.
+#
+# The libudev crate assumes libudev is being dynamically linked in, and
+# checks if its symbols are null before intializing anything else, so that
+# you can use it to detect if libudev is installed and gracefully
+# disable gamepads or whatever else if it's not.
+#
+# If we're missing any symbols the libudev crate needs, then rust will give
+# us a compilation error. It's not a problem if we export additional symbols.
+#
+# So while this is a bit of a weird hack, it works pretty robustly, and this
+# crate is basically just a header for libudev so it's not a particularly
+# significant maintenance burden.
+#
+# authenticator-rs: https://github.com/mozilla/authenticator-rs
+# libudev crate: https://crates.io/crates/libudev
+
+[package]
+name = "libudev-sys"
+version = "0.1.3"
+authors = ["Tim Taubert <ttaubert@mozilla.com>"]
+description = "FFI bindings to libudev"
+license = "MPL-2.0"
+
+[dependencies]
+lazy_static = "1.0"
+libc = "0.2"
diff --git a/dom/webauthn/libudev-sys/src/lib.rs b/dom/webauthn/libudev-sys/src/lib.rs
new file mode 100644
index 0000000000..a08234a4c6
--- /dev/null
+++ b/dom/webauthn/libudev-sys/src/lib.rs
@@ -0,0 +1,182 @@
+/* -*- Mode: rust; rust-indent-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#![allow(non_camel_case_types)]
+#![allow(non_upper_case_globals)]
+
+#[macro_use]
+extern crate lazy_static;
+extern crate libc;
+
+use libc::{c_void,c_int,c_char,c_ulonglong,dev_t};
+use libc::{RTLD_GLOBAL,RTLD_LAZY,RTLD_NOLOAD};
+use libc::{dlopen,dlclose,dlsym};
+use std::ffi::CString;
+use std::{marker,mem,ops,ptr};
+
+#[repr(C)]
+pub struct udev {
+  __private: c_void
+}
+
+#[repr(C)]
+pub struct udev_list_entry {
+  __private: c_void
+}
+
+#[repr(C)]
+pub struct udev_device {
+  __private: c_void
+}
+
+#[repr(C)]
+pub struct udev_monitor {
+  __private: c_void
+}
+
+#[repr(C)]
+pub struct udev_enumerate {
+  __private: c_void
+}
+
+macro_rules! ifnull {
+  ($a:expr, $b:expr) => {
+    if $a.is_null() { $b } else { $a }
+  }
+}
+
+struct Library(*mut c_void);
+
+impl Library {
+  fn open(name: &'static str) -> Library {
+    let flags = RTLD_LAZY | RTLD_GLOBAL;
+    let flags_noload = flags | RTLD_NOLOAD;
+    let name = CString::new(name).unwrap();
+    let name = name.as_ptr();
+
+    Library(unsafe {
+      ifnull!(dlopen(name, flags_noload), dlopen(name, flags))
+    })
+  }
+
+  fn get(&self, name: &'static str) -> *mut c_void {
+    let name = CString::new(name).unwrap();
+    unsafe { dlsym(self.0, name.as_ptr()) }
+  }
+}
+
+impl Drop for Library {
+  fn drop(&mut self) {
+    unsafe { dlclose(self.0); }
+  }
+}
+
+unsafe impl Sync for Library {}
+unsafe impl Send for Library {}
+
+lazy_static! {
+  static ref LIBRARY: Library = {
+    Library::open("libudev.so.1")
+  };
+}
+
+pub struct Symbol<T> {
+  ptr: *mut c_void,
+  pd: marker::PhantomData<T>
+}
+
+impl<T> Symbol<T> {
+  fn new(ptr: *mut c_void) -> Self {
+    let default = Self::default as *mut c_void;
+    Self { ptr: ifnull!(ptr, default), pd: marker::PhantomData }
+  }
+
+  // This is the default symbol, used whenever dlopen() fails.
+  // Users of this library are expected to check whether udev_new() returns
+  // a nullptr, and if so they MUST NOT call any other exported functions.
+  extern "C" fn default() -> *mut c_void {
+    ptr::null_mut()
+  }
+}
+
+impl<T> ops::Deref for Symbol<T> {
+  type Target = T;
+
+  fn deref(&self) -> &T {
+    unsafe { mem::transmute(&self.ptr) }
+  }
+}
+
+unsafe impl<T: Sync + Send> Sync for Symbol<T> {}
+unsafe impl<T: Sync + Send> Send for Symbol<T> {}
+
+macro_rules! define {
+  ($name:ident, $type:ty) => {
+    lazy_static! {
+      pub static ref $name : Symbol<$type> = {
+        Symbol::new(LIBRARY.get(stringify!($name)))
+      };
+    }
+  };
+}
+
+// udev
+define!(udev_new, extern "C" fn () -> *mut udev);
+define!(udev_unref, extern "C" fn (*mut udev) -> *mut udev);
+
+// udev_list
+define!(udev_list_entry_get_next, extern "C" fn (*mut udev_list_entry) -> *mut udev_list_entry);
+define!(udev_list_entry_get_name, extern "C" fn (*mut udev_list_entry) -> *const c_char);
+define!(udev_list_entry_get_value, extern "C" fn (*mut udev_list_entry) -> *const c_char);
+
+// udev_device
+define!(udev_device_ref, extern "C" fn (*mut udev_device) -> *mut udev_device);
+define!(udev_device_unref, extern "C" fn (*mut udev_device) -> *mut udev_device);
+define!(udev_device_new_from_syspath, extern "C" fn (*mut udev, *const c_char) -> *mut udev_device);
+define!(udev_device_get_parent, extern "C" fn (*mut udev_device) -> *mut udev_device);
+define!(udev_device_get_devpath, extern "C" fn (*mut udev_device) -> *const c_char);
+define!(udev_device_get_subsystem, extern "C" fn (*mut udev_device) -> *const c_char);
+define!(udev_device_get_devtype, extern "C" fn (*mut udev_device) -> *const c_char);
+define!(udev_device_get_syspath, extern "C" fn (*mut udev_device) -> *const c_char);
+define!(udev_device_get_sysname, extern "C" fn (*mut udev_device) -> *const c_char);
+define!(udev_device_get_sysnum, extern "C" fn (*mut udev_device) -> *const c_char);
+define!(udev_device_get_devnode, extern "C" fn (*mut udev_device) -> *const c_char);
+define!(udev_device_get_is_initialized, extern "C" fn (*mut udev_device) -> c_int);
+define!(udev_device_get_properties_list_entry, extern "C" fn (*mut udev_device) -> *mut udev_list_entry);
+define!(udev_device_get_property_value, extern "C" fn (*mut udev_device, *const c_char) -> *const c_char);
+define!(udev_device_get_driver, extern "C" fn (*mut udev_device) -> *const c_char);
+define!(udev_device_get_devnum, extern "C" fn (*mut udev_device) -> dev_t);
+define!(udev_device_get_action, extern "C" fn (*mut udev_device) -> *const c_char);
+define!(udev_device_get_sysattr_value, extern "C" fn (*mut udev_device, *const c_char) -> *const c_char);
+define!(udev_device_set_sysattr_value, extern "C" fn (*mut udev_device, *const c_char, *mut c_char) -> c_int);
+define!(udev_device_get_sysattr_list_entry, extern "C" fn (*mut udev_device) -> *mut udev_list_entry);
+define!(udev_device_get_seqnum, extern "C" fn (*mut udev_device) -> c_ulonglong);
+
+// udev_monitor
+define!(udev_monitor_ref, extern "C" fn (*mut udev_monitor) -> *mut udev_monitor);
+define!(udev_monitor_unref, extern "C" fn (*mut udev_monitor) -> *mut udev_monitor);
+define!(udev_monitor_new_from_netlink, extern "C" fn (*mut udev, *const c_char) -> *mut udev_monitor);
+define!(udev_monitor_enable_receiving, extern "C" fn (*mut udev_monitor) -> c_int);
+define!(udev_monitor_get_fd, extern "C" fn (*mut udev_monitor) -> c_int);
+define!(udev_monitor_receive_device, extern "C" fn (*mut udev_monitor) -> *mut udev_device);
+define!(udev_monitor_filter_add_match_subsystem_devtype, extern "C" fn (*mut udev_monitor, *const c_char, *const c_char) -> c_int);
+define!(udev_monitor_filter_add_match_tag, extern "C" fn (*mut udev_monitor, *const c_char) -> c_int);
+define!(udev_monitor_filter_remove, extern "C" fn (*mut udev_monitor) -> c_int);
+
+// udev_enumerate
+define!(udev_enumerate_unref, extern "C" fn (*mut udev_enumerate) -> *mut udev_enumerate);
+define!(udev_enumerate_new, extern "C" fn (*mut udev) -> *mut udev_enumerate);
+define!(udev_enumerate_add_match_subsystem, extern "C" fn (*mut udev_enumerate, *const c_char) -> c_int);
+define!(udev_enumerate_add_nomatch_subsystem, extern "C" fn (*mut udev_enumerate, *const c_char) -> c_int);
+define!(udev_enumerate_add_match_sysattr, extern "C" fn (*mut udev_enumerate, *const c_char, *const c_char) -> c_int);
+define!(udev_enumerate_add_nomatch_sysattr, extern "C" fn (*mut udev_enumerate, *const c_char, *const c_char) -> c_int);
+define!(udev_enumerate_add_match_property, extern "C" fn (*mut udev_enumerate, *const c_char, *const c_char) -> c_int);
+define!(udev_enumerate_add_match_tag, extern "C" fn (*mut udev_enumerate, *const c_char) -> c_int);
+define!(udev_enumerate_add_match_parent, extern "C" fn (*mut udev_enumerate, *mut udev_device) -> c_int);
+define!(udev_enumerate_add_match_is_initialized, extern "C" fn (*mut udev_enumerate) -> c_int);
+define!(udev_enumerate_add_match_sysname, extern "C" fn (*mut udev_enumerate, *const c_char) -> c_int);
+define!(udev_enumerate_add_syspath, extern "C" fn (*mut udev_enumerate, *const c_char) -> c_int);
+define!(udev_enumerate_scan_devices, extern "C" fn (*mut udev_enumerate) -> c_int);
+define!(udev_enumerate_get_list_entry, extern "C" fn (*mut udev_enumerate) -> *mut udev_list_entry);