Rollup merge of rust-lang#123196 - Ayush1325:uefi-process, r=joboet

Add Process support for UEFI

UEFI does not have an actual process. However, it does provide methods to launch and execute another UEFI image. Having process support is important since it is possible to run rust test suit using `Command::output` and is the first step towards being able to run it for UEFI.

Here is an overview of how the support is implemented.

- We create a copy of the SystemTable. This is required since at least OVMF seems to crash if the original system table is modified.
- Stdout and Stderr pipe works by registering a new `simple_text_output` Protocol and pointing the child system table to use those.
- `Stdio::Inherit` just points the console to the current running image console which seems to work with even 3 levels of process.
- `spawn` is left unimplemented since it does not make sense for UEFI architecture. Additionally, since rust-lang#105458 was merged, the `spawn` and `output` implementations are completely independent.

library/std/Cargo.toml

@@ -56,7 +56,7 @@ hermit-abi = { version = "0.4.0", features = ['rustc-dep-of-std'], public = true
 wasi = { version = "0.11.0", features = ['rustc-dep-of-std'], default-features = false }
 
 [target.'cfg(target_os = "uefi")'.dependencies]
-r-efi = { version = "4.2.0", features = ['rustc-dep-of-std'] }
+r-efi = { version = "4.5.0", features = ['rustc-dep-of-std'] }
 r-efi-alloc = { version = "1.0.0", features = ['rustc-dep-of-std'] }
 
 [features]

library/std/src/lib.rs

@@ -293,6 +293,7 @@
 #![feature(doc_masked)]
 #![feature(doc_notable_trait)]
 #![feature(dropck_eyepatch)]
+#![feature(extended_varargs_abi_support)]
 #![feature(f128)]
 #![feature(f16)]
 #![feature(if_let_guard)]

library/std/src/sys/pal/uefi/helpers.rs

@@ -12,15 +12,21 @@
 use r_efi::efi::{self, Guid};
 use r_efi::protocols::{device_path, device_path_to_text};
 
-use crate::ffi::OsString;
+use crate::ffi::{OsStr, OsString};
 use crate::io::{self, const_io_error};
 use crate::mem::{size_of, MaybeUninit};
-use crate::os::uefi::{self, env::boot_services, ffi::OsStringExt};
+use crate::os::uefi::{self, env::boot_services, ffi::OsStrExt, ffi::OsStringExt};
 use crate::ptr::NonNull;
 use crate::slice;
 use crate::sync::atomic::{AtomicPtr, Ordering};
 use crate::sys_common::wstr::WStrUnits;
 
+type BootInstallMultipleProtocolInterfaces =
+    unsafe extern "efiapi" fn(_: *mut r_efi::efi::Handle, _: ...) -> r_efi::efi::Status;
+
+type BootUninstallMultipleProtocolInterfaces =
+    unsafe extern "efiapi" fn(_: r_efi::efi::Handle, _: ...) -> r_efi::efi::Status;
+
 const BOOT_SERVICES_UNAVAILABLE: io::Error =
     const_io_error!(io::ErrorKind::Other, "Boot Services are no longer available");
 
@@ -221,3 +227,192 @@ pub(crate) fn runtime_services() -> Option<NonNull<r_efi::efi::RuntimeServices>>
     let runtime_services = unsafe { (*system_table.as_ptr()).runtime_services };
     NonNull::new(runtime_services)
 }
+
+pub(crate) struct DevicePath(NonNull<r_efi::protocols::device_path::Protocol>);
+
+impl DevicePath {
+    pub(crate) fn from_text(p: &OsStr) -> io::Result<Self> {
+        fn inner(
+            p: &OsStr,
+            protocol: NonNull<r_efi::protocols::device_path_from_text::Protocol>,
+        ) -> io::Result<DevicePath> {
+            let path_vec = p.encode_wide().chain(Some(0)).collect::<Vec<u16>>();
+            if path_vec[..path_vec.len() - 1].contains(&0) {
+                return Err(const_io_error!(
+                    io::ErrorKind::InvalidInput,
+                    "strings passed to UEFI cannot contain NULs",
+                ));
+            }
+
+            let path =
+                unsafe { ((*protocol.as_ptr()).convert_text_to_device_path)(path_vec.as_ptr()) };
+
+            NonNull::new(path).map(DevicePath).ok_or_else(|| {
+                const_io_error!(io::ErrorKind::InvalidFilename, "Invalid Device Path")
+            })
+        }
+
+        static LAST_VALID_HANDLE: AtomicPtr<crate::ffi::c_void> =
+            AtomicPtr::new(crate::ptr::null_mut());
+
+        if let Some(handle) = NonNull::new(LAST_VALID_HANDLE.load(Ordering::Acquire)) {
+            if let Ok(protocol) = open_protocol::<r_efi::protocols::device_path_from_text::Protocol>(
+                handle,
+                r_efi::protocols::device_path_from_text::PROTOCOL_GUID,
+            ) {
+                return inner(p, protocol);
+            }
+        }
+
+        let handles = locate_handles(r_efi::protocols::device_path_from_text::PROTOCOL_GUID)?;
+        for handle in handles {
+            if let Ok(protocol) = open_protocol::<r_efi::protocols::device_path_from_text::Protocol>(
+                handle,
+                r_efi::protocols::device_path_from_text::PROTOCOL_GUID,
+            ) {
+                LAST_VALID_HANDLE.store(handle.as_ptr(), Ordering::Release);
+                return inner(p, protocol);
+            }
+        }
+
+        io::Result::Err(const_io_error!(
+            io::ErrorKind::NotFound,
+            "DevicePathFromText Protocol not found"
+        ))
+    }
+
+    pub(crate) fn as_ptr(&self) -> *mut r_efi::protocols::device_path::Protocol {
+        self.0.as_ptr()
+    }
+}
+
+impl Drop for DevicePath {
+    fn drop(&mut self) {
+        if let Some(bt) = boot_services() {
+            let bt: NonNull<r_efi::efi::BootServices> = bt.cast();
+            unsafe {
+                ((*bt.as_ptr()).free_pool)(self.0.as_ptr() as *mut crate::ffi::c_void);
+            }
+        }
+    }
+}
+
+pub(crate) struct OwnedProtocol<T> {
+    guid: r_efi::efi::Guid,
+    handle: NonNull<crate::ffi::c_void>,
+    protocol: *mut T,
+}
+
+impl<T> OwnedProtocol<T> {
+    // FIXME: Consider using unsafe trait for matching protocol with guid
+    pub(crate) unsafe fn create(protocol: T, mut guid: r_efi::efi::Guid) -> io::Result<Self> {
+        let bt: NonNull<r_efi::efi::BootServices> =
+            boot_services().ok_or(BOOT_SERVICES_UNAVAILABLE)?.cast();
+        let protocol: *mut T = Box::into_raw(Box::new(protocol));
+        let mut handle: r_efi::efi::Handle = crate::ptr::null_mut();
+
+        // FIXME: Move into r-efi once extended_varargs_abi_support is stablized
+        let func: BootInstallMultipleProtocolInterfaces =
+            unsafe { crate::mem::transmute((*bt.as_ptr()).install_multiple_protocol_interfaces) };
+
+        let r = unsafe {
+            func(
+                &mut handle,
+                &mut guid as *mut _ as *mut crate::ffi::c_void,
+                protocol as *mut crate::ffi::c_void,
+                crate::ptr::null_mut() as *mut crate::ffi::c_void,
+            )
+        };
+
+        if r.is_error() {
+            drop(unsafe { Box::from_raw(protocol) });
+            return Err(crate::io::Error::from_raw_os_error(r.as_usize()));
+        };
+
+        let handle = NonNull::new(handle)
+            .ok_or(io::const_io_error!(io::ErrorKind::Uncategorized, "found null handle"))?;
+
+        Ok(Self { guid, handle, protocol })
+    }
+
+    pub(crate) fn handle(&self) -> NonNull<crate::ffi::c_void> {
+        self.handle
+    }
+}
+
+impl<T> Drop for OwnedProtocol<T> {
+    fn drop(&mut self) {
+        // Do not deallocate a runtime protocol
+        if let Some(bt) = boot_services() {
+            let bt: NonNull<r_efi::efi::BootServices> = bt.cast();
+            // FIXME: Move into r-efi once extended_varargs_abi_support is stablized
+            let func: BootUninstallMultipleProtocolInterfaces = unsafe {
+                crate::mem::transmute((*bt.as_ptr()).uninstall_multiple_protocol_interfaces)
+            };
+            let status = unsafe {
+                func(
+                    self.handle.as_ptr(),
+                    &mut self.guid as *mut _ as *mut crate::ffi::c_void,
+                    self.protocol as *mut crate::ffi::c_void,
+                    crate::ptr::null_mut() as *mut crate::ffi::c_void,
+                )
+            };
+
+            // Leak the protocol in case uninstall fails
+            if status == r_efi::efi::Status::SUCCESS {
+                let _ = unsafe { Box::from_raw(self.protocol) };
+            }
+        }
+    }
+}
+
+impl<T> AsRef<T> for OwnedProtocol<T> {
+    fn as_ref(&self) -> &T {
+        unsafe { self.protocol.as_ref().unwrap() }
+    }
+}
+
+pub(crate) struct OwnedTable<T> {
+    layout: crate::alloc::Layout,
+    ptr: *mut T,
+}
+
+impl<T> OwnedTable<T> {
+    pub(crate) fn from_table_header(hdr: &r_efi::efi::TableHeader) -> Self {
+        let header_size = hdr.header_size as usize;
+        let layout = crate::alloc::Layout::from_size_align(header_size, 8).unwrap();
+        let ptr = unsafe { crate::alloc::alloc(layout) as *mut T };
+        Self { layout, ptr }
+    }
+
+    pub(crate) const fn as_ptr(&self) -> *const T {
+        self.ptr
+    }
+
+    pub(crate) const fn as_mut_ptr(&self) -> *mut T {
+        self.ptr
+    }
+}
+
+impl OwnedTable<r_efi::efi::SystemTable> {
+    pub(crate) fn from_table(tbl: *const r_efi::efi::SystemTable) -> Self {
+        let hdr = unsafe { (*tbl).hdr };
+
+        let owned_tbl = Self::from_table_header(&hdr);
+        unsafe {
+            crate::ptr::copy_nonoverlapping(
+                tbl as *const u8,
+                owned_tbl.as_mut_ptr() as *mut u8,
+                hdr.header_size as usize,
+            )
+        };
+
+        owned_tbl
+    }
+}
+
+impl<T> Drop for OwnedTable<T> {
+    fn drop(&mut self) {
+        unsafe { crate::alloc::dealloc(self.ptr as *mut u8, self.layout) };
+    }
+}

library/std/src/sys/pal/uefi/mod.rs

@@ -25,7 +25,6 @@ pub mod net;
 pub mod os;
 #[path = "../unsupported/pipe.rs"]
 pub mod pipe;
-#[path = "../unsupported/process.rs"]
 pub mod process;
 pub mod stdio;
 pub mod thread;