1 files changed, 54 insertions, 0 deletions
diff --git a/library/std/src/os/uefi/env.rs b/library/std/src/os/uefi/env.rs
new file mode 100644
index 00000000000..479ff5f6975
--- /dev/null
+++ b/library/std/src/os/uefi/env.rs
@@ -0,0 +1,54 @@
+//! UEFI-specific extensions to the primitives in `std::env` module
+
+use crate::ffi::c_void;
+use crate::ptr::NonNull;
+use crate::sync::atomic::{AtomicPtr, Ordering};
+use crate::sync::OnceLock;
+
+// Position 0 = SystemTable
+// Position 1 = ImageHandle
+static GLOBALS: OnceLock<(AtomicPtr<c_void>, AtomicPtr<c_void>)> = OnceLock::new();
+
+/// Initializes the global System Table and Image Handle pointers.
+///
+/// The standard library requires access to the UEFI System Table and the Application Image Handle
+/// to operate. Those are provided to UEFI Applications via their application entry point. By
+/// calling `init_globals()`, those pointers are retained by the standard library for future use.
+/// The pointers are never exposed to any entity outside of this application and it is guaranteed
+/// that, once the application exited, these pointers are never dereferenced again.
+///
+/// Callers are required to ensure the pointers are valid for the entire lifetime of this
+/// application. In particular, UEFI Boot Services must not be exited while an application with the
+/// standard library is loaded.
+///
+/// This function must not be called more than once.
+#[unstable(feature = "uefi_std", issue = "100499")]
+pub unsafe fn init_globals(handle: NonNull<c_void>, system_table: NonNull<c_void>) {
+    GLOBALS.set((AtomicPtr::new(system_table.as_ptr()), AtomicPtr::new(handle.as_ptr()))).unwrap()
+}
+
+/// Get the SystemTable Pointer.
+/// Note: This function panics if the System Table and Image Handle is Not initialized
+#[unstable(feature = "uefi_std", issue = "100499")]
+pub fn system_table() -> NonNull<c_void> {
+    try_system_table().unwrap()
+}
+
+/// Get the SystemHandle Pointer.
+/// Note: This function panics if the System Table and Image Handle is Not initialized
+#[unstable(feature = "uefi_std", issue = "100499")]
+pub fn image_handle() -> NonNull<c_void> {
+    try_image_handle().unwrap()
+}
+
+/// Get the SystemTable Pointer.
+/// This function is mostly intended for places where panic is not an option
+pub(crate) fn try_system_table() -> Option<NonNull<crate::ffi::c_void>> {
+    NonNull::new(GLOBALS.get()?.0.load(Ordering::Acquire))
+}
+
+/// Get the SystemHandle Pointer.
+/// This function is mostly intended for places where panic is not an option
+pub(crate) fn try_image_handle() -> Option<NonNull<crate::ffi::c_void>> {
+    NonNull::new(GLOBALS.get()?.1.load(Ordering::Acquire))
+}