1 files changed, 42 insertions, 0 deletions
diff --git a/library/std/src/sys/sgx/abi/panic.rs b/library/std/src/sys/sgx/abi/panic.rs
new file mode 100644
index 00000000000..229b3b3291f
--- /dev/null
+++ b/library/std/src/sys/sgx/abi/panic.rs
@@ -0,0 +1,42 @@
+use super::usercalls::alloc::UserRef;
+use crate::cmp;
+use crate::io::{self, Write};
+use crate::mem;
+
+extern "C" {
+    fn take_debug_panic_buf_ptr() -> *mut u8;
+    static DEBUG: u8;
+}
+
+pub(crate) struct SgxPanicOutput(Option<&'static mut UserRef<[u8]>>);
+
+fn empty_user_slice() -> &'static mut UserRef<[u8]> {
+    unsafe { UserRef::from_raw_parts_mut(1 as *mut u8, 0) }
+}
+
+impl SgxPanicOutput {
+    pub(crate) fn new() -> Option<Self> {
+        if unsafe { DEBUG == 0 } { None } else { Some(SgxPanicOutput(None)) }
+    }
+
+    fn init(&mut self) -> &mut &'static mut UserRef<[u8]> {
+        self.0.get_or_insert_with(|| unsafe {
+            let ptr = take_debug_panic_buf_ptr();
+            if ptr.is_null() { empty_user_slice() } else { UserRef::from_raw_parts_mut(ptr, 1024) }
+        })
+    }
+}
+
+impl Write for SgxPanicOutput {
+    fn write(&mut self, src: &[u8]) -> io::Result<usize> {
+        let dst = mem::replace(self.init(), empty_user_slice());
+        let written = cmp::min(src.len(), dst.len());
+        dst[..written].copy_from_enclave(&src[..written]);
+        self.0 = Some(&mut dst[written..]);
+        Ok(written)
+    }
+
+    fn flush(&mut self) -> io::Result<()> {
+        Ok(())
+    }
+}