elf_loader 0.17.0

A no_std-friendly ELF loader and runtime linker for Rust.
Documentation 
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#[cfg(feature = "object")]
use crate::RelocReason;
#[cfg(feature = "object")]
use crate::memory::VmAddr;

/// Result of a relocation hook.
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub enum HandleResult {
    /// The handler did not process this relocation.
    Unhandled,
    /// The handler processed this relocation.
    Handled,
}

impl HandleResult {
    /// Returns whether the handler left the relocation for the next stage.
    #[inline]
    pub const fn is_unhandled(self) -> bool {
        matches!(self, Self::Unhandled)
    }
}

/// A wrapper type for raw values written into relocation slots.
///
/// Address-like relocation results use [`VmAddr`]; this type keeps plain
/// integer payloads distinct from unchecked writes.
#[must_use = "relocation arithmetic returns a new value"]
#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
#[repr(transparent)]
pub(crate) struct RelocValue<T>(T);

#[cfg(feature = "object")]
pub(crate) type RelocSWord32 = RelocValue<i32>;

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub(crate) enum RelocationValueFormula {
    Absolute,
    RelativeToPlace,
}

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub(crate) enum RelocationValueKind {
    None,
    Address(RelocationValueFormula),
    Word32(RelocationValueFormula),
    SWord32(RelocationValueFormula),
}

impl<T> RelocValue<T> {
    #[inline]
    pub(crate) const fn new(val: T) -> Self {
        Self(val)
    }

    #[inline]
    pub(crate) fn into_inner(self) -> T {
        self.0
    }
}

impl RelocationValueFormula {
    #[inline]
    pub(crate) fn compute(self, target: usize, addend: isize, place: usize) -> i128 {
        let target = target as i128;
        let addend = addend as i128;
        let place = place as i128;

        match self {
            RelocationValueFormula::Absolute => target + addend,
            RelocationValueFormula::RelativeToPlace => target + addend - place,
        }
    }
}

#[cfg(feature = "object")]
impl VmAddr {
    #[inline]
    pub(crate) fn try_into_sword32(self) -> core::result::Result<RelocSWord32, RelocReason> {
        i32::try_from(self.get() as isize)
            .map(RelocValue::new)
            .map_err(|_| RelocReason::IntConversionOutOfRange)
    }
}

#[cfg(feature = "object")]
impl RelocSWord32 {
    #[inline]
    pub(crate) const fn to_ne_bytes(self) -> [u8; 4] {
        self.0.to_ne_bytes()
    }
}