proto/media: add LoadFile2Protocol

https://uefi.org/specs/UEFI/2.10/13_Protocols_Media_Access.html#load-file-2-protocol

Author: RaitoBezarius

uefi/src/proto/media/load_file.rs

@@ -0,0 +1,86 @@
+//! Load file support protocols.
+
+#[cfg(feature = "alloc")]
+use alloc::vec::Vec;
+
+use crate::proto::device_path::{FfiDevicePath, DevicePath};
+use crate::proto::unsafe_protocol;
+use crate::{Result, Status};
+use core::ffi::c_void;
+use core::ptr;
+
+/// The UEFI LoadFile2 protocol.
+///
+/// This protocol has a single method to load a file according to some
+/// device path.
+///
+/// This interface is implemented by many devices, e.g. network and filesystems.
+#[derive(Debug)]
+#[repr(C)]
+#[unsafe_protocol("4006c0c1-fcb3-403e-996d-4a6c8724e06d")]
+pub struct LoadFile2Protocol {
+    load_file: unsafe extern "efiapi" fn(
+        this: &mut LoadFile2Protocol,
+        file_path: *const FfiDevicePath,
+        boot_policy: bool,
+        buffer_size: *mut usize,
+        buffer: *mut c_void,
+    ) -> Status,
+}
+
+impl LoadFile2Protocol {
+    /// Load file addressed by provided device path
+    pub fn load_file(&mut self,
+        file_path: &DevicePath,
+        boot_policy: bool,
+        buffer_size: &mut usize,
+        buffer: *mut c_void
+    ) -> Status {
+        unsafe {
+            (self.load_file)(self,
+                file_path.as_ffi_ptr(),
+                boot_policy,
+                buffer_size as *mut usize,
+                buffer
+            )
+        }
+    }
+
+    #[cfg(feature = "alloc")]
+    /// Load file addressed by the provided device path.
+    pub fn load_file_in_heap(&mut self,
+        file_path: &DevicePath,
+        boot_policy: bool,
+    ) -> Result<Vec<u8>> {
+        let mut buffer_size: usize = 0;
+        let mut status: Status;
+        unsafe {
+            status = (self.load_file)(self,
+                file_path.as_ffi_ptr(),
+                boot_policy,
+                ptr::addr_of_mut!(buffer_size),
+                ptr::null_mut()
+            );
+        }
+
+        if status.is_error() {
+            return Err(status.into());
+        }
+
+        let mut buffer: Vec<u8> = Vec::with_capacity(buffer_size);
+        unsafe {
+            status = (self.load_file)(self,
+                file_path.as_ffi_ptr(),
+                boot_policy,
+                ptr::addr_of_mut!(buffer_size),
+                buffer.as_mut_ptr() as *mut c_void
+            );
+        }
+
+        if status.is_error() {
+            return Err(status.into());
+        }
+
+        Ok(buffer)
+    }
+}

uefi/src/proto/media/mod.rs

@@ -10,3 +10,4 @@ pub mod block;
 pub mod disk;
 pub mod fs;
 pub mod partition;
+pub mod load_file;