Merge pull request #1570 from stlankes/dup2

add syscalls corresponding to dup2 and isatty

src/fd/mod.rs

@@ -256,6 +256,11 @@ pub(crate) trait ObjectInterface: Sync + Send + core::fmt::Debug {
 	async fn ioctl(&self, _cmd: IoCtl, _value: bool) -> io::Result<()> {
 		Err(io::Error::ENOSYS)
 	}
+
+	/// `isatty` returns `true` for a terminal device
+	async fn isatty(&self) -> io::Result<bool> {
+		Ok(false)
+	}
 }
 
 pub(crate) fn read(fd: FileDescriptor, buf: &mut [u8]) -> io::Result<usize> {
@@ -379,6 +384,15 @@ pub(crate) fn dup_object(fd: FileDescriptor) -> io::Result<FileDescriptor> {
 	block_on(core_scheduler().dup_object(fd), None)
 }
 
+pub(crate) fn dup_object2(fd1: FileDescriptor, fd2: FileDescriptor) -> io::Result<FileDescriptor> {
+	block_on(core_scheduler().dup_object2(fd1, fd2), None)
+}
+
 pub(crate) fn remove_object(fd: FileDescriptor) -> io::Result<Arc<dyn ObjectInterface>> {
 	block_on(core_scheduler().remove_object(fd), None)
 }
+
+pub(crate) fn isatty(fd: FileDescriptor) -> io::Result<bool> {
+	let obj = get_object(fd)?;
+	block_on(obj.isatty(), None)
+}

src/fd/stdio.rs

@@ -53,6 +53,10 @@ impl ObjectInterface for GenericStdin {
 		})
 		.await
 	}
+
+	async fn isatty(&self) -> io::Result<bool> {
+		Ok(true)
+	}
 }
 
 impl GenericStdin {
@@ -75,6 +79,10 @@ impl ObjectInterface for GenericStdout {
 		CONSOLE.lock().write(buf);
 		Ok(buf.len())
 	}
+
+	async fn isatty(&self) -> io::Result<bool> {
+		Ok(true)
+	}
 }
 
 impl GenericStdout {
@@ -97,6 +105,10 @@ impl ObjectInterface for GenericStderr {
 		CONSOLE.lock().write(buf);
 		Ok(buf.len())
 	}
+
+	async fn isatty(&self) -> io::Result<bool> {
+		Ok(true)
+	}
 }
 
 impl GenericStderr {
@@ -108,7 +120,12 @@ impl GenericStderr {
 #[derive(Debug)]
 pub struct UhyveStdin;
 
-impl ObjectInterface for UhyveStdin {}
+#[async_trait]
+impl ObjectInterface for UhyveStdin {
+	async fn isatty(&self) -> io::Result<bool> {
+		Ok(true)
+	}
+}
 
 impl UhyveStdin {
 	pub const fn new() -> Self {
@@ -136,6 +153,10 @@ impl ObjectInterface for UhyveStdout {
 
 		Ok(write_params.len)
 	}
+
+	async fn isatty(&self) -> io::Result<bool> {
+		Ok(true)
+	}
 }
 
 impl UhyveStdout {
@@ -164,6 +185,10 @@ impl ObjectInterface for UhyveStderr {
 
 		Ok(write_params.len)
 	}
+
+	async fn isatty(&self) -> io::Result<bool> {
+		Ok(true)
+	}
 }
 
 impl UhyveStderr {

src/scheduler/mod.rs

@@ -572,6 +572,28 @@ impl PerCoreScheduler {
 		.await
 	}
 
+	pub async fn dup_object2(
+		&self,
+		fd1: FileDescriptor,
+		fd2: FileDescriptor,
+	) -> io::Result<FileDescriptor> {
+		future::poll_fn(|cx| {
+			without_interrupts(|| {
+				let borrowed = self.current_task.borrow();
+				let mut pinned_obj = core::pin::pin!(borrowed.object_map.write());
+				let mut guard = ready!(pinned_obj.as_mut().poll(cx));
+				let obj = guard.get(&fd1).cloned().ok_or(io::Error::EBADF)?;
+
+				if guard.try_insert(fd2, obj).is_err() {
+					Ready(Err(io::Error::EMFILE))
+				} else {
+					Ready(Ok(fd2))
+				}
+			})
+		})
+		.await
+	}
+
 	/// Remove a IO interface, which is named by the file descriptor
 	pub async fn remove_object(&self, fd: FileDescriptor) -> io::Result<Arc<dyn ObjectInterface>> {
 		future::poll_fn(|cx| {

src/syscalls/mod.rs

@@ -22,7 +22,7 @@ pub use self::timer::*;
 use crate::executor::block_on;
 use crate::fd::{
 	AccessPermission, EventFlags, FileDescriptor, IoCtl, OpenOption, PollFd, dup_object,
-	get_object, remove_object,
+	dup_object2, get_object, isatty, remove_object,
 };
 use crate::fs::{self, FileAttr};
 #[cfg(all(target_os = "none", not(feature = "common-os")))]
@@ -634,6 +634,27 @@ pub extern "C" fn sys_dup(fd: i32) -> i32 {
 	dup_object(fd).unwrap_or_else(|e| -num::ToPrimitive::to_i32(&e).unwrap())
 }
 
+#[hermit_macro::system]
+#[unsafe(no_mangle)]
+pub extern "C" fn sys_dup2(fd1: i32, fd2: i32) -> i32 {
+	dup_object2(fd1, fd2).unwrap_or_else(|e| -num::ToPrimitive::to_i32(&e).unwrap())
+}
+
+#[hermit_macro::system]
+#[unsafe(no_mangle)]
+pub extern "C" fn sys_isatty(fd: i32) -> i32 {
+	match isatty(fd) {
+		Err(e) => -num::ToPrimitive::to_i32(&e).unwrap(),
+		Ok(v) => {
+			if v {
+				1
+			} else {
+				0
+			}
+		}
+	}
+}
+
 #[hermit_macro::system]
 #[unsafe(no_mangle)]
 pub unsafe extern "C" fn sys_poll(fds: *mut PollFd, nfds: usize, timeout: i32) -> i32 {