Move uefi-exts into core as an optional feature

Author: GabrielMajeri

Cargo.toml

@@ -1,10 +1,14 @@
 [package]
 name = "uefi"
-version = "0.3.1"
+version = "0.3.2"
 authors = ["Gabriel Majeri <[email protected]>"]
 readme = "README.md"
 edition = "2018"
-exclude = ["uefi-test-runner/**"]
+exclude = [
+    "uefi-macros/**",
+    "uefi-services/**",
+    "uefi-test-runner/**",
+]
 description = "Safe and easy-to-use wrapper for building UEFI apps"
 repository = "https://github.com/rust-osdev/uefi-rs"
 keywords = ["uefi", "efi"]
@@ -19,6 +23,7 @@ is-it-maintained-open-issues = { repository = "rust-osdev/uefi-rs" }
 [features]
 default = []
 alloc = []
+exts = []
 logger = []
 
 [dependencies]
@@ -29,7 +34,6 @@ uefi-macros = "0.2.1"
 
 [workspace]
 members = [
-    "uefi-exts",
     "uefi-macros",
     "uefi-services",
     "uefi-test-runner",

README.md

@@ -44,9 +44,8 @@ This project contains multiple sub-crates:
   - `logger`: logging implementation for the standard [log] crate.
     - Prints output to console.
     - No buffering is done: this is not a high-performance logger.
-
-- `uefi-exts`: extension traits providing utility functions for common patterns.
-  - Requires the `alloc` crate (either enable the `alloc` optional feature or your own custom allocator).
+  - `exts`: extensions providing utility functions for common patterns.
+    - Requires the `alloc` crate (either enable the `alloc` optional feature or your own custom allocator).
 
 - `uefi-macros`: procedural macros that are used to derive some traits in `uefi`.
 

uefi-exts/src/lib.rs renamed to src/exts.rs

@@ -1,28 +1,16 @@
 //! Utility functions for the most common UEFI patterns.
-//!
-//! This crate simply exports some extension traits
-//! which add utility functions to various UEFI objects.
 
-#![no_std]
-#![feature(alloc_layout_extra, allocator_api)]
-
-extern crate alloc;
-
-mod boot;
-mod file;
-
-pub use self::boot::BootServicesExt;
-pub use self::file::FileExt;
-
-use alloc::{
+use alloc_api::{
     alloc::{handle_alloc_error, Alloc, Global, Layout},
     boxed::Box,
 };
 use core::slice;
 
 /// Creates a boxed byte buffer using the standard allocator
+///
 /// # Panics
-/// Calls handle_alloc_error if the layout has a size of zero or allocation fails.
+///
+/// Calls `handle_alloc_error` if the layout has a size of zero or allocation fails.
 pub fn allocate_buffer(layout: Layout) -> Box<[u8]> {
     if layout.size() == 0 {
         handle_alloc_error(layout);

src/lib.rs

@@ -23,13 +23,18 @@
 //! For example, a PC with no network card might not contain a network driver,
 //! therefore all the network protocols will be unavailable.
 
+#![cfg_attr(feature = "exts", feature(allocator_api, alloc_layout_extra))]
 #![feature(optin_builtin_traits)]
 #![feature(try_trait)]
 #![no_std]
 // Enable some additional warnings and lints.
 #![warn(missing_docs, unused)]
 #![deny(clippy::all)]
 
+// `uefi-exts` requires access to memory allocation APIs.
+#[cfg(feature = "exts")]
+extern crate alloc as alloc_api;
+
 #[macro_use]
 pub mod data_types;
 pub use self::data_types::{unsafe_guid, Identify};
@@ -47,5 +52,8 @@ pub mod prelude;
 #[cfg(feature = "alloc")]
 pub mod alloc;
 
+#[cfg(feature = "exts")]
+pub mod exts;
+
 #[cfg(feature = "logger")]
 pub mod logger;

src/proto/media/file/mod.rs

@@ -12,6 +12,8 @@ mod regular;
 
 use crate::prelude::*;
 use crate::{CStr16, Char16, Guid, Result, Status};
+#[cfg(feature = "exts")]
+use alloc_api::{alloc::Layout, boxed::Box};
 use bitflags::bitflags;
 use core::ffi::c_void;
 use core::mem;
@@ -168,6 +170,47 @@ pub trait File: Sized {
     fn flush(&mut self) -> Result {
         (self.imp().flush)(self.imp()).into()
     }
+
+    #[cfg(feature = "exts")]
+    /// Get the dynamically allocated info for a file
+    fn get_boxed_info<Info: FileProtocolInfo + ?Sized>(&mut self) -> Result<Box<Info>> {
+        // Initially try get_info with an empty array, this should always fail
+        // as all Info types at least need room for a null-terminator.
+        let size = match self
+            .get_info::<Info>(&mut [])
+            .expect_error("zero sized get_info unexpectedly succeeded")
+            .split()
+        {
+            (s, None) => return Err(s.into()),
+            (_, Some(size)) => size,
+        };
+
+        // We add trailing padding because the size of a rust structure must
+        // always be a multiple of alignment.
+        let layout = Layout::from_size_align(size, Info::alignment())
+            .unwrap()
+            .pad_to_align()
+            .unwrap();
+        let mut buffer = crate::exts::allocate_buffer(layout);
+        let buffer_start = buffer.as_ptr();
+
+        let info = self
+            .get_info(&mut buffer)
+            .discard_errdata()?
+            .map(|info_ref| {
+                // This operation is safe because info uses the exact memory
+                // of the provied buffer (so no memory is leaked), and the box
+                // is created if and only if buffer is leaked (so no memory can
+                // ever be freed twice).
+
+                assert_eq!(mem::size_of_val(info_ref), layout.size());
+                assert_eq!(info_ref as *const Info as *const u8, buffer_start);
+                unsafe { Box::from_raw(info_ref as *mut _) }
+            });
+        mem::forget(buffer);
+
+        Ok(info)
+    }
 }
 
 // Internal File helper methods to access the funciton pointer table.

src/table/boot.rs

@@ -4,6 +4,8 @@ use super::Header;
 use crate::data_types::Align;
 use crate::proto::Protocol;
 use crate::{Event, Guid, Handle, Result, Status};
+#[cfg(feature = "exts")]
+use alloc_api::vec::Vec;
 use bitflags::bitflags;
 use core::cell::UnsafeCell;
 use core::ffi::c_void;
@@ -485,6 +487,38 @@ impl BootServices {
     }
 }
 
+#[cfg(feature = "exts")]
+impl BootServices {
+    /// Returns all the handles implementing a certain protocol.
+    pub fn find_handles<P: Protocol>(&self) -> Result<Vec<Handle>> {
+        // Search by protocol.
+        let search_type = SearchType::from_proto::<P>();
+
+        // Determine how much we need to allocate.
+        let (status1, buffer_size) = self.locate_handle(search_type, None)?.split();
+
+        // Allocate a large enough buffer.
+        let mut buffer = Vec::with_capacity(buffer_size);
+
+        unsafe {
+            buffer.set_len(buffer_size);
+        }
+
+        // Perform the search.
+        let (status2, buffer_size) = self.locate_handle(search_type, Some(&mut buffer))?.split();
+
+        // Once the vector has been filled, update its size.
+        unsafe {
+            buffer.set_len(buffer_size);
+        }
+
+        // Emit output, with warnings
+        status1
+            .into_with_val(|| buffer)
+            .map(|completion| completion.with_status(status2))
+    }
+}
+
 impl super::Table for BootServices {
     const SIGNATURE: u64 = 0x5652_4553_544f_4f42;
 }

uefi-exts/Cargo.toml

@@ -6,9 +6,8 @@ publish = false
 edition = "2018"
 
 [dependencies]
-uefi = { path = ".." }
+uefi = { path = "..", features = ['exts'] }
 uefi-services = { path = "../uefi-services" }
-uefi-exts = { path = "../uefi-exts" }
 
 log = { version = "0.4.8", default-features = false }
 

uefi-exts/src/boot.rs

@@ -1,5 +1,4 @@
 use uefi::prelude::*;
-use uefi_exts::BootServicesExt;
 
 use uefi::proto;