diff --git a/library/std/src/sys/pal/uefi/helpers.rs b/library/std/src/sys/pal/uefi/helpers.rs index 7504a0f7ad7..dccc137d6f5 100644 --- a/library/std/src/sys/pal/uefi/helpers.rs +++ b/library/std/src/sys/pal/uefi/helpers.rs @@ -14,10 +14,12 @@ use r_efi::protocols::{device_path, device_path_to_text, shell}; use crate::ffi::{OsStr, OsString}; use crate::io::{self, const_error}; +use crate::marker::PhantomData; use crate::mem::{MaybeUninit, size_of}; use crate::os::uefi::env::boot_services; use crate::os::uefi::ffi::{OsStrExt, OsStringExt}; use crate::os::uefi::{self}; +use crate::path::Path; use crate::ptr::NonNull; use crate::slice; use crate::sync::atomic::{AtomicPtr, Ordering}; @@ -278,6 +280,10 @@ impl OwnedDevicePath { pub(crate) const fn as_ptr(&self) -> *mut r_efi::protocols::device_path::Protocol { self.0.as_ptr() } + + pub(crate) const fn borrow<'a>(&'a self) -> BorrowedDevicePath<'a> { + BorrowedDevicePath::new(self.0) + } } impl Drop for OwnedDevicePath { @@ -293,13 +299,37 @@ impl Drop for OwnedDevicePath { impl crate::fmt::Debug for OwnedDevicePath { fn fmt(&self, f: &mut crate::fmt::Formatter<'_>) -> crate::fmt::Result { - match device_path_to_text(self.0) { + match self.borrow().to_text() { Ok(p) => p.fmt(f), Err(_) => f.debug_struct("OwnedDevicePath").finish_non_exhaustive(), } } } +pub(crate) struct BorrowedDevicePath<'a> { + protocol: NonNull, + phantom: PhantomData<&'a r_efi::protocols::device_path::Protocol>, +} + +impl<'a> BorrowedDevicePath<'a> { + pub(crate) const fn new(protocol: NonNull) -> Self { + Self { protocol, phantom: PhantomData } + } + + pub(crate) fn to_text(&self) -> io::Result { + device_path_to_text(self.protocol) + } +} + +impl<'a> crate::fmt::Debug for BorrowedDevicePath<'a> { + fn fmt(&self, f: &mut crate::fmt::Formatter<'_>) -> crate::fmt::Result { + match self.to_text() { + Ok(p) => p.fmt(f), + Err(_) => f.debug_struct("BorrowedDevicePath").finish_non_exhaustive(), + } + } +} + pub(crate) struct OwnedProtocol { guid: r_efi::efi::Guid, handle: NonNull, @@ -452,3 +482,21 @@ pub(crate) fn open_shell() -> Option> { None } + +/// Get device path protocol associated with shell mapping. +/// +/// returns None in case no such mapping is exists +pub(crate) fn get_device_path_from_map(map: &Path) -> io::Result> { + let shell = + open_shell().ok_or(io::const_error!(io::ErrorKind::NotFound, "UEFI Shell not found"))?; + let mut path = os_string_to_raw(map.as_os_str()) + .ok_or(io::const_error!(io::ErrorKind::InvalidFilename, "Invalid UEFI shell mapping"))?; + + // The Device Path Protocol pointer returned by UEFI shell is owned by the shell and is not + // freed throughout it's lifetime. So it has a 'static lifetime. + let protocol = unsafe { ((*shell.as_ptr()).get_device_path_from_map)(path.as_mut_ptr()) }; + let protocol = NonNull::new(protocol) + .ok_or(io::const_error!(io::ErrorKind::NotFound, "UEFI Shell mapping not found"))?; + + Ok(BorrowedDevicePath::new(protocol)) +} diff --git a/library/std/src/sys/path/mod.rs b/library/std/src/sys/path/mod.rs index 24a94ec7828..1fa4e80d678 100644 --- a/library/std/src/sys/path/mod.rs +++ b/library/std/src/sys/path/mod.rs @@ -5,12 +5,12 @@ cfg_if::cfg_if! { } else if #[cfg(all(target_vendor = "fortanix", target_env = "sgx"))] { mod sgx; pub use sgx::*; - } else if #[cfg(any( - target_os = "uefi", - target_os = "solid_asp3", - ))] { + } else if #[cfg(target_os = "solid_asp3")] { mod unsupported_backslash; pub use unsupported_backslash::*; + } else if #[cfg(target_os = "uefi")] { + mod uefi; + pub use uefi::*; } else { mod unix; pub use unix::*; diff --git a/library/std/src/sys/path/uefi.rs b/library/std/src/sys/path/uefi.rs new file mode 100644 index 00000000000..a3f4a3bfe1b --- /dev/null +++ b/library/std/src/sys/path/uefi.rs @@ -0,0 +1,105 @@ +#![forbid(unsafe_op_in_unsafe_fn)] +use crate::ffi::OsStr; +use crate::io; +use crate::path::{Path, PathBuf, Prefix}; +use crate::sys::{helpers, unsupported_err}; + +const FORWARD_SLASH: u8 = b'/'; +const COLON: u8 = b':'; + +#[inline] +pub fn is_sep_byte(b: u8) -> bool { + b == b'\\' +} + +#[inline] +pub fn is_verbatim_sep(b: u8) -> bool { + b == b'\\' +} + +pub fn parse_prefix(_: &OsStr) -> Option> { + None +} + +pub const MAIN_SEP_STR: &str = "\\"; +pub const MAIN_SEP: char = '\\'; + +/// UEFI paths can be of 4 types: +/// +/// 1. Absolute Shell Path: Uses shell mappings (eg: `FS0:`). Does not exist if UEFI shell not present. +/// It can be identified with `:`. +/// Eg: FS0:\abc\run.efi +/// +/// 2. Absolute Device Path: this is what we want +/// It can be identified with `/`. +/// Eg: PciRoot(0x0)/Pci(0x1,0x1)/Ata(Secondary,Slave,0x0)/\abc\run.efi +/// +/// 3: Relative root: path relative to the current volume. +/// It will start with `\`. +/// Eg: \abc\run.efi +/// +/// 4: Relative +/// Eg: run.efi +/// +/// The algorithm is mostly taken from edk2 UEFI shell implementation and is +/// somewhat simple. Check for the path type in order. +/// +/// The volume mapping in Absolute Shell Path (not the rest of the path) can be converted to Device +/// Path Protocol using `EFI_SHELL->GetDevicePathFromMap`. The rest of the path (Relative root +/// path), can just be appended to the remaining path. +/// +/// For Relative root, we get the current volume (either in Shell Mapping, or Device Path Protocol +/// form) and join it with the relative root path. We then recurse the function to resolve the Shell +/// Mapping if present. +/// +/// For Relative paths, we use the current working directory to construct +/// the new path and recurse the function to resolve the Shell mapping if present. +/// +/// Finally, at the end, we get the 2nd form, i.e. Absolute Device Path, which can be used in the +/// normal UEFI APIs such as file, process, etc. +/// Eg: PciRoot(0x0)/Pci(0x1,0x1)/Ata(Secondary,Slave,0x0)/\abc\run.efi +pub(crate) fn absolute(path: &Path) -> io::Result { + // Absolute Shell Path + if path.as_os_str().as_encoded_bytes().contains(&COLON) { + let mut path_components = path.components(); + // Since path is not empty, it has at least one Component + let prefix = path_components.next().unwrap(); + + let dev_path = helpers::get_device_path_from_map(prefix.as_ref())?; + let mut dev_path_text = dev_path.to_text().map_err(|_| unsupported_err())?; + + // UEFI Shell does not seem to end device path with `/` + if *dev_path_text.as_encoded_bytes().last().unwrap() != FORWARD_SLASH { + dev_path_text.push("/"); + } + + let mut ans = PathBuf::from(dev_path_text); + ans.push(path_components); + + return Ok(ans); + } + + // Absolute Device Path + if path.as_os_str().as_encoded_bytes().contains(&FORWARD_SLASH) { + return Ok(path.to_path_buf()); + } + + // cur_dir() always returns something + let cur_dir = crate::env::current_dir().unwrap(); + let mut path_components = path.components(); + + // Relative Root + if path_components.next().unwrap() == crate::path::Component::RootDir { + let mut ans = PathBuf::new(); + ans.push(cur_dir.components().next().unwrap()); + ans.push(path_components); + return absolute(&ans); + } + + absolute(&cur_dir.join(path)) +} + +pub(crate) fn is_absolute(path: &Path) -> bool { + let temp = path.as_os_str().as_encoded_bytes(); + temp.contains(&COLON) || temp.contains(&FORWARD_SLASH) +}