Implement creating an Idevice with a file descriptor

cpp/include/idevice++/idevice.hpp

@@ -32,6 +32,7 @@ using IdevicePtr = std::unique_ptr<IdeviceHandle, FnDeleter<IdeviceHandle, idevi
 class Idevice {
   public:
     static Result<Idevice, FfiError> create(IdeviceSocketHandle* socket, const std::string& label);
+    static Result<Idevice, FfiError> from_fd(int fd, const std::string& label);
 
     static Result<Idevice, FfiError>
     create_tcp(const sockaddr* addr, socklen_t addr_len, const std::string& label);

cpp/src/idevice.cpp

@@ -13,6 +13,15 @@ Result<Idevice, FfiError> Idevice::create(IdeviceSocketHandle* socket, const std
     return Ok(Idevice(h));
 }
 
+Result<Idevice, FfiError> Idevice::from_fd(int fd, const std::string& label) {
+    IdeviceHandle* h = nullptr;
+    FfiError       e(idevice_from_fd(fd, label.c_str(), &h));
+    if (e) {
+        return Err(e);
+    }
+    return Ok(Idevice(h));
+}
+
 Result<Idevice, FfiError>
 Idevice::create_tcp(const sockaddr* addr, socklen_t addr_len, const std::string& label) {
     IdeviceHandle* h = nullptr;

ffi/src/lib.rs

@@ -48,6 +48,7 @@ use idevice::{Idevice, IdeviceSocket, ReadWrite};
 use once_cell::sync::Lazy;
 use std::{
     ffi::{CStr, CString, c_char},
+    os::fd::FromRawFd,
     ptr::null_mut,
 };
 use tokio::runtime::{self, Runtime};
@@ -122,6 +123,46 @@ pub unsafe extern "C" fn idevice_new(
     null_mut()
 }
 
+/// Creates an Idevice object from a socket file descriptor
+///
+/// # Safety
+/// The socket FD must be valid.
+/// The pointers must be valid and non-null.
+#[unsafe(no_mangle)]
+pub unsafe extern "C" fn idevice_from_fd(
+    fd: i32,
+    label: *const c_char,
+    idevice: *mut *mut IdeviceHandle,
+) -> *mut IdeviceFfiError {
+    if label.is_null() || idevice.is_null() || fd == 0 {
+        return ffi_err!(IdeviceError::FfiInvalidArg);
+    }
+
+    // Get socket ownership
+    let fd = unsafe { libc::dup(fd) };
+    let socket = unsafe { std::net::TcpStream::from_raw_fd(fd) };
+    if let Err(e) = socket.set_nonblocking(true) {
+        return ffi_err!(e);
+    }
+    let socket = match RUNTIME.block_on(async move { tokio::net::TcpStream::from_std(socket) }) {
+        Ok(s) => s,
+        Err(e) => return ffi_err!(e),
+    };
+
+    // Convert C string to Rust string
+    let c_str = match unsafe { CStr::from_ptr(label).to_str() } {
+        Ok(s) => s,
+        Err(_) => return ffi_err!(IdeviceError::FfiInvalidString),
+    };
+
+    // Create new Idevice instance
+    let dev = Idevice::new(Box::new(socket), c_str);
+    let boxed = Box::new(IdeviceHandle(dev));
+    unsafe { *idevice = Box::into_raw(boxed) };
+
+    null_mut()
+}
+
 /// Creates a new Idevice connection
 ///
 /// # Arguments