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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,120 @@ | ||
| //! Implementation for UEFI using EFI_RNG_PROTOCOL | ||
| use crate::Error; | ||
| use core::{ | ||
| mem::MaybeUninit, | ||
| ptr::{self, null_mut, NonNull}, | ||
| sync::atomic::{AtomicPtr, Ordering::Relaxed}, | ||
| }; | ||
| use r_efi::{ | ||
| efi::{BootServices, Handle}, | ||
| protocols::rng, | ||
| }; | ||
|
|
||
| extern crate std; | ||
|
|
||
| pub use crate::util::{inner_u32, inner_u64}; | ||
|
|
||
| #[cfg(not(target_os = "uefi"))] | ||
| compile_error!("`efi_rng` backend can be enabled only for UEFI targets!"); | ||
|
|
||
| static RNG_PROTOCOL: AtomicPtr<rng::Protocol> = AtomicPtr::new(null_mut()); | ||
|
|
||
| fn init() -> Result<NonNull<rng::Protocol>, Error> { | ||
| const HANDLE_SIZE: usize = size_of::<Handle>(); | ||
|
|
||
| let boot_services = std::os::uefi::env::boot_services() | ||
| .ok_or(Error::BOOT_SERVICES_UNAVAILABLE)? | ||
| .cast::<BootServices>(); | ||
|
|
||
| let mut handles = [ptr::null_mut(); 16]; | ||
| // `locate_handle` operates with length in bytes | ||
| let mut buf_size = handles.len() * HANDLE_SIZE; | ||
| let mut guid = rng::PROTOCOL_GUID; | ||
| let ret = unsafe { | ||
| ((*boot_services.as_ptr()).locate_handle)( | ||
| r_efi::efi::BY_PROTOCOL, | ||
| &mut guid, | ||
| null_mut(), | ||
| &mut buf_size, | ||
| handles.as_mut_ptr(), | ||
| ) | ||
| }; | ||
|
|
||
| if ret.is_error() { | ||
| return Err(Error::TEMP_EFI_ERROR); | ||
| } | ||
|
|
||
| let handles_len = buf_size / HANDLE_SIZE; | ||
| let handles = handles.get(..handles_len).ok_or(Error::UNEXPECTED)?; | ||
|
|
||
| let system_handle = std::os::uefi::env::image_handle(); | ||
| for &handle in handles { | ||
| let mut protocol: MaybeUninit<*mut rng::Protocol> = MaybeUninit::uninit(); | ||
|
|
||
| let mut protocol_guid = rng::PROTOCOL_GUID; | ||
| let ret = unsafe { | ||
| ((*boot_services.as_ptr()).open_protocol)( | ||
| handle, | ||
| &mut protocol_guid, | ||
| protocol.as_mut_ptr().cast(), | ||
| system_handle.as_ptr(), | ||
| ptr::null_mut(), | ||
| r_efi::system::OPEN_PROTOCOL_GET_PROTOCOL, | ||
| ) | ||
| }; | ||
|
|
||
| let protocol = if ret.is_error() { | ||
| continue; | ||
| } else { | ||
| let protocol = unsafe { protocol.assume_init() }; | ||
| NonNull::new(protocol).ok_or(Error::UNEXPECTED)? | ||
| }; | ||
|
|
||
| // Try to use the acquired protocol handle | ||
| let mut buf = [0u8; 8]; | ||
| let ret = unsafe { | ||
| ((*protocol.as_ptr()).get_rng)( | ||
| protocol.as_ptr(), | ||
| ptr::null_mut(), | ||
| buf.len(), | ||
| buf.as_mut_ptr(), | ||
| ) | ||
| }; | ||
|
|
||
| if ret.is_error() { | ||
| continue; | ||
| } | ||
|
|
||
| RNG_PROTOCOL.store(protocol.as_ptr(), Relaxed); | ||
| return Ok(protocol); | ||
| } | ||
| Err(Error::NO_RNG_HANDLE) | ||
| } | ||
|
|
||
| pub fn fill_inner(dest: &mut [MaybeUninit<u8>]) -> Result<(), Error> { | ||
| let protocol = match NonNull::new(RNG_PROTOCOL.load(Relaxed)) { | ||
| Some(p) => p, | ||
| None => init()?, | ||
| }; | ||
|
|
||
| let ret = unsafe { | ||
| ((*protocol.as_ptr()).get_rng)( | ||
| protocol.as_ptr(), | ||
| ptr::null_mut(), | ||
| dest.len(), | ||
| dest.as_mut_ptr().cast::<u8>(), | ||
| ) | ||
| }; | ||
|
|
||
| if ret.is_error() { | ||
| Err(Error::TEMP_EFI_ERROR) | ||
| } else { | ||
| Ok(()) | ||
| } | ||
| } | ||
|
|
||
| impl Error { | ||
| pub(crate) const BOOT_SERVICES_UNAVAILABLE: Error = Self::new_internal(10); | ||
| pub(crate) const NO_RNG_HANDLE: Error = Self::new_internal(11); | ||
| pub(crate) const TEMP_EFI_ERROR: Error = Self::new_internal(12); | ||
| } |
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