feat(cliprdr): add a Linux clipboard backend

crates/ironrdp-client/src/lib.rs

@@ -12,7 +12,7 @@ pub mod output_channel;
 pub mod rail;
 pub mod rdp;
 
-#[cfg(all(windows, feature = "clipboard"))]
+#[cfg(all(any(windows, target_os = "linux"), feature = "clipboard"))]
 mod clipboard;
 
 mod ws;

crates/ironrdp-client/src/rdp.rs

@@ -790,14 +790,21 @@ impl RdpClient {
         // ── Clipboard initialisation (compile-time gated) ─────────────────────
         //
         // On Windows the WinClipboard object must outlive the entire connection loop, so we
-        // keep it alive via `_win_clipboard`.  On non-Windows a StubClipboard backend is used
-        // and its ownership can be released immediately after the factory is extracted.
+        // keep it alive via `_win_clipboard`; the same goes for LinuxClipboard and
+        // `_linux_clipboard`. Elsewhere a StubClipboard backend is used and its ownership can be
+        // released immediately after the factory is extracted.
         #[cfg(all(windows, feature = "clipboard"))]
         #[expect(
             clippy::collection_is_never_read,
             reason = "binding owns the Windows clipboard so it stays alive for the connection's lifetime"
         )]
         let _win_clipboard;
+        #[cfg(all(target_os = "linux", feature = "clipboard"))]
+        #[expect(
+            clippy::collection_is_never_read,
+            reason = "binding owns the Linux clipboard so it stays alive for the connection's lifetime"
+        )]
+        let mut _linux_clipboard = None;
 
         #[cfg(feature = "clipboard")]
         let cliprdr_factory: Option<Box<dyn CliprdrBackendFactory + Send>>;
@@ -852,7 +859,25 @@ impl RdpClient {
                         }
                     }
 
-                    #[cfg(not(windows))]
+                    #[cfg(target_os = "linux")]
+                    {
+                        use crate::clipboard::ClientClipboardMessageProxy;
+                        use ironrdp_cliprdr_native::{LinuxClipboard, StubClipboard};
+                        match LinuxClipboard::new(ClientClipboardMessageProxy::new(self.input_event_sender.clone())) {
+                            Ok(clipboard) => {
+                                cliprdr_factory = Some(clipboard.backend_factory());
+                                _linux_clipboard = Some(clipboard);
+                            }
+                            Err(error) => {
+                                // Without a desktop clipboard there is nothing to bridge, and the
+                                // session is still useful, so this is not a connection failure.
+                                warn!(%error, "OS clipboard unavailable; clipboard redirection is off for this session");
+                                cliprdr_factory = Some(StubClipboard::new().backend_factory());
+                            }
+                        }
+                    }
+
+                    #[cfg(not(any(windows, target_os = "linux")))]
                     {
                         use ironrdp_cliprdr_native::StubClipboard;
                         let stub = StubClipboard::new();

crates/ironrdp-cliprdr-native/Cargo.toml

@@ -12,6 +12,10 @@ authors.workspace = true
 keywords.workspace = true
 categories.workspace = true
 
+[features]
+# Exposes internals to the integration tests in ironrdp-testsuite-core.
+__test = ["dep:visibility"]
+
 [lib]
 doctest = false
 test = false
@@ -21,6 +25,15 @@ ironrdp-cliprdr = { path = "../ironrdp-cliprdr", version = "0.7" } # public
 ironrdp-core = { path = "../ironrdp-core", version = "0.2" }
 tracing = { version = "0.1", features = ["log"] }
 
+[target.'cfg(target_os = "linux")'.dependencies]
+nix = { version = "0.31", features = ["fs", "poll"] }
+visibility = { version = "0.1", optional = true }
+wayland-client = "0.31"
+wayland-protocols = { version = "0.32", features = ["client", "staging"] }
+wayland-protocols-wlr = { version = "0.3", features = ["client"] }
+x11rb = { version = "0.13", features = ["xfixes"] }
+ironrdp-cliprdr-format = { path = "../ironrdp-cliprdr-format", version = "0.2" }
+
 [target.'cfg(windows)'.dependencies]
 windows = { version = "0.62", features = [
     "Win32_Foundation",

crates/ironrdp-cliprdr-native/README.md

@@ -1,7 +1,35 @@
 # IronRDP CLIPRDR native backends
 
-Native CLIPRDR backend implementations. Currently only Windows is supported.
+Native CLIPRDR backend implementations: Windows (`WinClipboard`) and Linux desktops over X11 and Wayland (`LinuxClipboard`, text and images).
 
 This crate is part of the [IronRDP] project.
 
 [IronRDP]: https://github.com/Devolutions/IronRDP
+
+## Linux
+
+`LinuxClipboard` uses the shared `data_control` client for Wayland compositors offering `ext-data-control-v1` or `wlr-data-control-unstable-v1`.
+When data-control is unavailable, including on GNOME, it falls back to X11/XWayland through XFixes and selection ownership.
+A desktop without either clipboard service uses the client's stub backend.
+
+Both backends react to selection changes and advertise remote formats without fetching their contents.
+Text (`CF_UNICODETEXT`) and images (`CF_DIB`/`CF_DIBV5`, converted to/from PNG by `ironrdp-cliprdr-format`) are requested only when an application pastes.
+Local clipboard content is read only when the peer requests it.
+File clipboard transfer and HTML are not supported.
+
+Only one Format Data Request is outstanding at a time, because responses do not identify their request.
+A paste times out after five seconds, but its outstanding request is retained until the late response is drained.
+If the peer never replies, new remote pastes fail until the clipboard channel is reinitialized; this prevents stale content from being mistaken for a newer copy.
+Selection changes cancel older paste waiters, and the existing `ironrdp_cliprdr::loop_detector` detects content echoed by clipboard managers.
+
+The clipboard workers bound data transfers and pending pastes.
+X11 transfers use INCR for large content and separate requestor windows so late selection responses cannot complete newer reads.
+
+State-machine tests run in the normal CI suite with `cargo test -p ironrdp-testsuite-core cliprdr_native`.
+Three additional integration tests require a dedicated X11 display; the interoperability test also requires `xclip`:
+
+```sh
+DISPLAY=:N cargo test -p ironrdp-testsuite-core cliprdr_native::linux::x11_ -- --ignored --test-threads=1
+```
+
+Use a private display such as Xvfb for these tests, because they replace its clipboard selection.