Auto merge of #136780 - joboet:move_pal_stdio, r=Amanieu

std: move stdio to `sys`

As per #117276, this moves the platform definitions of `Stdout` and friends into `sys`. This PR also unifies the UNIX and Hermit implementations and moves the `__rust_print_err` function needed by libunwind on SGX into the dedicated module for such helper functions.

1 files changed, 106 insertions, 0 deletions

diff --git a/library/std/src/sys/stdio/unix.rs b/library/std/src/sys/stdio/unix.rs
new file mode 100644
index 00000000000..8d133857c59
--- /dev/null
+++ b/library/std/src/sys/stdio/unix.rs
@@ -0,0 +1,106 @@
+#[cfg(target_os = "hermit")]
+use hermit_abi::{EBADF, STDERR_FILENO, STDIN_FILENO, STDOUT_FILENO};
+#[cfg(target_family = "unix")]
+use libc::{EBADF, STDERR_FILENO, STDIN_FILENO, STDOUT_FILENO};
+
+#[cfg(target_family = "unix")]
+use crate::io::BorrowedCursor;
+use crate::io::{self, IoSlice, IoSliceMut};
+use crate::mem::ManuallyDrop;
+#[cfg(target_os = "hermit")]
+use crate::os::hermit::io::FromRawFd;
+#[cfg(target_family = "unix")]
+use crate::os::unix::io::FromRawFd;
+use crate::sys::fd::FileDesc;
+
+pub struct Stdin(());
+pub struct Stdout(());
+pub struct Stderr(());
+
+impl Stdin {
+    pub const fn new() -> Stdin {
+        Stdin(())
+    }
+}
+
+impl io::Read for Stdin {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        unsafe { ManuallyDrop::new(FileDesc::from_raw_fd(STDIN_FILENO)).read(buf) }
+    }
+
+    #[cfg(not(target_os = "hermit"))]
+    fn read_buf(&mut self, buf: BorrowedCursor<'_>) -> io::Result<()> {
+        unsafe { ManuallyDrop::new(FileDesc::from_raw_fd(STDIN_FILENO)).read_buf(buf) }
+    }
+
+    fn read_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> io::Result<usize> {
+        unsafe { ManuallyDrop::new(FileDesc::from_raw_fd(STDIN_FILENO)).read_vectored(bufs) }
+    }
+
+    #[inline]
+    fn is_read_vectored(&self) -> bool {
+        true
+    }
+}
+
+impl Stdout {
+    pub const fn new() -> Stdout {
+        Stdout(())
+    }
+}
+
+impl io::Write for Stdout {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        unsafe { ManuallyDrop::new(FileDesc::from_raw_fd(STDOUT_FILENO)).write(buf) }
+    }
+
+    fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> io::Result<usize> {
+        unsafe { ManuallyDrop::new(FileDesc::from_raw_fd(STDOUT_FILENO)).write_vectored(bufs) }
+    }
+
+    #[inline]
+    fn is_write_vectored(&self) -> bool {
+        true
+    }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> {
+        Ok(())
+    }
+}
+
+impl Stderr {
+    pub const fn new() -> Stderr {
+        Stderr(())
+    }
+}
+
+impl io::Write for Stderr {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        unsafe { ManuallyDrop::new(FileDesc::from_raw_fd(STDERR_FILENO)).write(buf) }
+    }
+
+    fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> io::Result<usize> {
+        unsafe { ManuallyDrop::new(FileDesc::from_raw_fd(STDERR_FILENO)).write_vectored(bufs) }
+    }
+
+    #[inline]
+    fn is_write_vectored(&self) -> bool {
+        true
+    }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> {
+        Ok(())
+    }
+}
+
+pub fn is_ebadf(err: &io::Error) -> bool {
+    err.raw_os_error() == Some(EBADF as i32)
+}
+
+pub const STDIN_BUF_SIZE: usize = crate::sys::io::DEFAULT_BUF_SIZE;
+
+pub fn panic_output() -> Option<impl io::Write> {
+    Some(Stderr::new())
+}