[miri] make closing stdio file descriptions noops

std supports redirecting stdio file descriptors.

src/tools/miri/src/shims/files.rs

@@ -249,6 +249,15 @@ impl FileDescription for io::Stdin {
         finish.call(ecx, result)
     }
 
+    fn destroy<'tcx>(
+        self,
+        _self_id: FdId,
+        _communicate_allowed: bool,
+        _ecx: &mut MiriInterpCx<'tcx>,
+    ) -> InterpResult<'tcx, io::Result<()>> {
+        interp_ok(Ok(()))
+    }
+
     fn is_tty(&self, communicate_allowed: bool) -> bool {
         communicate_allowed && self.is_terminal()
     }
@@ -279,6 +288,15 @@ impl FileDescription for io::Stdout {
         finish.call(ecx, result)
     }
 
+    fn destroy<'tcx>(
+        self,
+        _self_id: FdId,
+        _communicate_allowed: bool,
+        _ecx: &mut MiriInterpCx<'tcx>,
+    ) -> InterpResult<'tcx, io::Result<()>> {
+        interp_ok(Ok(()))
+    }
+
     fn is_tty(&self, communicate_allowed: bool) -> bool {
         communicate_allowed && self.is_terminal()
     }
@@ -289,6 +307,15 @@ impl FileDescription for io::Stderr {
         "stderr"
     }
 
+    fn destroy<'tcx>(
+        self,
+        _self_id: FdId,
+        _communicate_allowed: bool,
+        _ecx: &mut MiriInterpCx<'tcx>,
+    ) -> InterpResult<'tcx, io::Result<()>> {
+        interp_ok(Ok(()))
+    }
+
     fn write<'tcx>(
         self: FileDescriptionRef<Self>,
         _communicate_allowed: bool,
@@ -436,6 +463,15 @@ impl FileDescription for NullOutput {
         // We just don't write anything, but report to the user that we did.
         finish.call(ecx, Ok(len))
     }
+
+    fn destroy<'tcx>(
+        self,
+        _self_id: FdId,
+        _communicate_allowed: bool,
+        _ecx: &mut MiriInterpCx<'tcx>,
+    ) -> InterpResult<'tcx, io::Result<()>> {
+        interp_ok(Ok(()))
+    }
 }
 
 /// Internal type of a file-descriptor - this is what [`FdTable`] expects

src/tools/miri/tests/pass-dep/libc/libc-fs.rs

@@ -48,6 +48,7 @@ fn main() {
     test_nofollow_not_symlink();
     #[cfg(target_os = "macos")]
     test_ioctl();
+    test_close_stdout();
 }
 
 fn test_file_open_unix_allow_two_args() {
@@ -579,3 +580,11 @@ fn test_ioctl() {
         assert_eq!(libc::ioctl(fd, libc::FIOCLEX), 0);
     }
 }
+
+fn test_close_stdout() {
+    // This is std library UB, but that's not relevant since we're
+    // only interacting with libc here.
+    unsafe {
+        libc::close(1);
+    }
+}