From c9879f770245813ae8c4ea81d49ebb306379fe80 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Kr=C3=B6ning?=
 <martin.kroening@eonerc.rwth-aachen.de>
Date: Tue, 4 Mar 2025 19:07:42 +0100
Subject: [PATCH] feat(fd): implement `fcntl(F_GETFL)`

---
 src/fd/mod.rs          |  5 +++++
 src/fd/socket/tcp.rs   | 14 ++++++++++++++
 src/fd/socket/udp.rs   | 14 ++++++++++++++
 src/fd/socket/vsock.rs | 14 ++++++++++++++
 src/syscalls/mod.rs    | 12 ++++++++++++
 5 files changed, 59 insertions(+)

diff --git a/src/fd/mod.rs b/src/fd/mod.rs
index e366f66a88..f44e232c68 100644
--- a/src/fd/mod.rs
+++ b/src/fd/mod.rs
@@ -253,6 +253,11 @@ pub(crate) trait ObjectInterface: Sync + Send + core::fmt::Debug {
 		Err(io::Error::ENOSYS)
 	}
 
+	/// Returns the file status flags.
+	async fn status_flags(&self) -> io::Result<StatusFlags> {
+		Err(io::Error::ENOSYS)
+	}
+
 	/// Sets the file status flags.
 	async fn set_status_flags(&self, _status_flags: StatusFlags) -> io::Result<()> {
 		Err(io::Error::ENOSYS)
diff --git a/src/fd/socket/tcp.rs b/src/fd/socket/tcp.rs
index 401a8f0006..86a9983fb8 100644
--- a/src/fd/socket/tcp.rs
+++ b/src/fd/socket/tcp.rs
@@ -434,6 +434,16 @@ impl Socket {
 		}
 	}
 
+	async fn status_flags(&self) -> io::Result<fd::StatusFlags> {
+		let status_flags = if self.is_nonblocking {
+			fd::StatusFlags::O_NONBLOCK
+		} else {
+			fd::StatusFlags::empty()
+		};
+
+		Ok(status_flags)
+	}
+
 	async fn set_status_flags(&mut self, status_flags: fd::StatusFlags) -> io::Result<()> {
 		self.is_nonblocking = status_flags.contains(fd::StatusFlags::O_NONBLOCK);
 		Ok(())
@@ -502,6 +512,10 @@ impl ObjectInterface for async_lock::RwLock<Socket> {
 		self.read().await.shutdown(how).await
 	}
 
+	async fn status_flags(&self) -> io::Result<fd::StatusFlags> {
+		self.read().await.status_flags().await
+	}
+
 	async fn set_status_flags(&self, status_flags: fd::StatusFlags) -> io::Result<()> {
 		self.write().await.set_status_flags(status_flags).await
 	}
diff --git a/src/fd/socket/udp.rs b/src/fd/socket/udp.rs
index 836d763f16..b770cc3fb2 100644
--- a/src/fd/socket/udp.rs
+++ b/src/fd/socket/udp.rs
@@ -215,6 +215,16 @@ impl Socket {
 		}
 	}
 
+	async fn status_flags(&self) -> io::Result<fd::StatusFlags> {
+		let status_flags = if self.nonblocking {
+			fd::StatusFlags::O_NONBLOCK
+		} else {
+			fd::StatusFlags::empty()
+		};
+
+		Ok(status_flags)
+	}
+
 	async fn set_status_flags(&mut self, status_flags: fd::StatusFlags) -> io::Result<()> {
 		self.nonblocking = status_flags.contains(fd::StatusFlags::O_NONBLOCK);
 		Ok(())
@@ -258,6 +268,10 @@ impl ObjectInterface for async_lock::RwLock<Socket> {
 		self.read().await.write(buf).await
 	}
 
+	async fn status_flags(&self) -> io::Result<fd::StatusFlags> {
+		self.read().await.status_flags().await
+	}
+
 	async fn set_status_flags(&self, status_flags: fd::StatusFlags) -> io::Result<()> {
 		self.write().await.set_status_flags(status_flags).await
 	}
diff --git a/src/fd/socket/vsock.rs b/src/fd/socket/vsock.rs
index e2f68a3430..bb7cd5e85d 100644
--- a/src/fd/socket/vsock.rs
+++ b/src/fd/socket/vsock.rs
@@ -296,6 +296,16 @@ impl Socket {
 		Ok(())
 	}
 
+	async fn status_flags(&self) -> io::Result<fd::StatusFlags> {
+		let status_flags = if self.is_nonblocking {
+			fd::StatusFlags::O_NONBLOCK
+		} else {
+			fd::StatusFlags::empty()
+		};
+
+		Ok(status_flags)
+	}
+
 	async fn set_status_flags(&mut self, status_flags: fd::StatusFlags) -> io::Result<()> {
 		self.is_nonblocking = status_flags.contains(fd::StatusFlags::O_NONBLOCK);
 		Ok(())
@@ -450,6 +460,10 @@ impl ObjectInterface for async_lock::RwLock<Socket> {
 		self.read().await.shutdown(how).await
 	}
 
+	async fn status_flags(&self) -> io::Result<fd::StatusFlags> {
+		self.read().await.status_flags().await
+	}
+
 	async fn set_status_flags(&self, status_flags: fd::StatusFlags) -> io::Result<()> {
 		self.write().await.set_status_flags(status_flags).await
 	}
diff --git a/src/syscalls/mod.rs b/src/syscalls/mod.rs
index 4c58609534..b2154c809c 100644
--- a/src/syscalls/mod.rs
+++ b/src/syscalls/mod.rs
@@ -537,11 +537,23 @@ pub unsafe extern "C" fn sys_ioctl(
 #[unsafe(no_mangle)]
 pub extern "C" fn sys_fcntl(fd: i32, cmd: i32, arg: i32) -> i32 {
 	const F_SETFD: i32 = 2;
+	const F_GETFL: i32 = 3;
 	const F_SETFL: i32 = 4;
 	const FD_CLOEXEC: i32 = 1;
 
 	if cmd == F_SETFD && arg == FD_CLOEXEC {
 		0
+	} else if cmd == F_GETFL {
+		let obj = get_object(fd);
+		obj.map_or_else(
+			|e| -num::ToPrimitive::to_i32(&e).unwrap(),
+			|v| {
+				block_on((*v).status_flags(), None).map_or_else(
+					|e| -num::ToPrimitive::to_i32(&e).unwrap(),
+					|status_flags| status_flags.bits(),
+				)
+			},
+		)
 	} else if cmd == F_SETFL {
 		let obj = get_object(fd);
 		obj.map_or_else(