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use alloc::fmt;
use alloc::vec::Vec;
use core::fmt::Debug;
use core::slice;
use crate::elf;
use crate::endian::{self, Endianness};
use crate::pod::Pod;
use crate::read::{
self, Error, ReadRef, Relocation, RelocationEncoding, RelocationKind, RelocationTarget,
SectionIndex, SymbolIndex,
};
use super::{ElfFile, FileHeader, SectionHeader, SectionTable};
/// A mapping from section index to associated relocation sections.
#[derive(Debug)]
pub struct RelocationSections {
relocations: Vec<usize>,
}
impl RelocationSections {
/// Create a new mapping using the section table.
///
/// Skips relocation sections that do not use the given symbol table section.
pub fn parse<'data, Elf: FileHeader, R: ReadRef<'data>>(
endian: Elf::Endian,
sections: &SectionTable<'data, Elf, R>,
symbol_section: SectionIndex,
) -> read::Result<Self> {
let mut relocations = vec![0; sections.len()];
for (index, section) in sections.iter().enumerate().rev() {
let sh_type = section.sh_type(endian);
if sh_type == elf::SHT_REL || sh_type == elf::SHT_RELA {
// The symbol indices used in relocations must be for the symbol table
// we are expecting to use.
let sh_link = SectionIndex(section.sh_link(endian) as usize);
if sh_link != symbol_section {
continue;
}
let sh_info = section.sh_info(endian) as usize;
if sh_info == 0 {
// Skip dynamic relocations.
continue;
}
if sh_info >= relocations.len() {
return Err(Error("Invalid ELF sh_info for relocation section"));
}
// Handle multiple relocation sections by chaining them.
let next = relocations[sh_info];
relocations[sh_info] = index;
relocations[index] = next;
}
}
Ok(Self { relocations })
}
/// Given a section index, return the section index of the associated relocation section.
///
/// This may also be called with a relocation section index, and it will return the
/// next associated relocation section.
pub fn get(&self, index: usize) -> Option<usize> {
self.relocations.get(index).cloned().filter(|x| *x != 0)
}
}
pub(super) enum ElfRelaIterator<'data, Elf: FileHeader> {
Rel(slice::Iter<'data, Elf::Rel>),
Rela(slice::Iter<'data, Elf::Rela>),
}
impl<'data, Elf: FileHeader> ElfRelaIterator<'data, Elf> {
fn is_rel(&self) -> bool {
match self {
ElfRelaIterator::Rel(_) => true,
ElfRelaIterator::Rela(_) => false,
}
}
}
impl<'data, Elf: FileHeader> Iterator for ElfRelaIterator<'data, Elf> {
type Item = Elf::Rela;
fn next(&mut self) -> Option<Self::Item> {
match self {
ElfRelaIterator::Rel(ref mut i) => i.next().cloned().map(Self::Item::from),
ElfRelaIterator::Rela(ref mut i) => i.next().cloned(),
}
}
}
/// An iterator over the dynamic relocations for an `ElfFile32`.
pub type ElfDynamicRelocationIterator32<'data, 'file, Endian = Endianness, R = &'data [u8]> =
ElfDynamicRelocationIterator<'data, 'file, elf::FileHeader32<Endian>, R>;
/// An iterator over the dynamic relocations for an `ElfFile64`.
pub type ElfDynamicRelocationIterator64<'data, 'file, Endian = Endianness, R = &'data [u8]> =
ElfDynamicRelocationIterator<'data, 'file, elf::FileHeader64<Endian>, R>;
/// An iterator over the dynamic relocations for an `ElfFile`.
pub struct ElfDynamicRelocationIterator<'data, 'file, Elf, R = &'data [u8]>
where
Elf: FileHeader,
R: ReadRef<'data>,
{
/// The current relocation section index.
pub(super) section_index: SectionIndex,
pub(super) file: &'file ElfFile<'data, Elf, R>,
pub(super) relocations: Option<ElfRelaIterator<'data, Elf>>,
}
impl<'data, 'file, Elf, R> Iterator for ElfDynamicRelocationIterator<'data, 'file, Elf, R>
where
Elf: FileHeader,
R: ReadRef<'data>,
{
type Item = (u64, Relocation);
fn next(&mut self) -> Option<Self::Item> {
let endian = self.file.endian;
loop {
if let Some(ref mut relocations) = self.relocations {
if let Some(reloc) = relocations.next() {
let relocation =
parse_relocation(self.file.header, endian, reloc, relocations.is_rel());
return Some((reloc.r_offset(endian).into(), relocation));
}
self.relocations = None;
}
let section = self.file.sections.section(self.section_index).ok()?;
self.section_index.0 += 1;
let sh_link = SectionIndex(section.sh_link(endian) as usize);
if sh_link != self.file.dynamic_symbols.section() {
continue;
}
match section.sh_type(endian) {
elf::SHT_REL => {
if let Ok(relocations) = section.data_as_array(endian, self.file.data) {
self.relocations = Some(ElfRelaIterator::Rel(relocations.iter()));
}
}
elf::SHT_RELA => {
if let Ok(relocations) = section.data_as_array(endian, self.file.data) {
self.relocations = Some(ElfRelaIterator::Rela(relocations.iter()));
}
}
_ => {}
}
}
}
}
impl<'data, 'file, Elf, R> fmt::Debug for ElfDynamicRelocationIterator<'data, 'file, Elf, R>
where
Elf: FileHeader,
R: ReadRef<'data>,
{
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_struct("ElfDynamicRelocationIterator").finish()
}
}
/// An iterator over the relocations for an `ElfSection32`.
pub type ElfSectionRelocationIterator32<'data, 'file, Endian = Endianness, R = &'data [u8]> =
ElfSectionRelocationIterator<'data, 'file, elf::FileHeader32<Endian>, R>;
/// An iterator over the relocations for an `ElfSection64`.
pub type ElfSectionRelocationIterator64<'data, 'file, Endian = Endianness, R = &'data [u8]> =
ElfSectionRelocationIterator<'data, 'file, elf::FileHeader64<Endian>, R>;
/// An iterator over the relocations for an `ElfSection`.
pub struct ElfSectionRelocationIterator<'data, 'file, Elf, R = &'data [u8]>
where
Elf: FileHeader,
R: ReadRef<'data>,
{
/// The current pointer in the chain of relocation sections.
pub(super) section_index: SectionIndex,
pub(super) file: &'file ElfFile<'data, Elf, R>,
pub(super) relocations: Option<ElfRelaIterator<'data, Elf>>,
}
impl<'data, 'file, Elf, R> Iterator for ElfSectionRelocationIterator<'data, 'file, Elf, R>
where
Elf: FileHeader,
R: ReadRef<'data>,
{
type Item = (u64, Relocation);
fn next(&mut self) -> Option<Self::Item> {
let endian = self.file.endian;
loop {
if let Some(ref mut relocations) = self.relocations {
if let Some(reloc) = relocations.next() {
let relocation =
parse_relocation(self.file.header, endian, reloc, relocations.is_rel());
return Some((reloc.r_offset(endian).into(), relocation));
}
self.relocations = None;
}
self.section_index = SectionIndex(self.file.relocations.get(self.section_index.0)?);
// The construction of RelocationSections ensures section_index is valid.
let section = self.file.sections.section(self.section_index).unwrap();
match section.sh_type(endian) {
elf::SHT_REL => {
if let Ok(relocations) = section.data_as_array(endian, self.file.data) {
self.relocations = Some(ElfRelaIterator::Rel(relocations.iter()));
}
}
elf::SHT_RELA => {
if let Ok(relocations) = section.data_as_array(endian, self.file.data) {
self.relocations = Some(ElfRelaIterator::Rela(relocations.iter()));
}
}
_ => {}
}
}
}
}
impl<'data, 'file, Elf, R> fmt::Debug for ElfSectionRelocationIterator<'data, 'file, Elf, R>
where
Elf: FileHeader,
R: ReadRef<'data>,
{
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_struct("ElfSectionRelocationIterator").finish()
}
}
fn parse_relocation<Elf: FileHeader>(
header: &Elf,
endian: Elf::Endian,
reloc: Elf::Rela,
implicit_addend: bool,
) -> Relocation {
let mut encoding = RelocationEncoding::Generic;
let is_mips64el = header.is_mips64el(endian);
let (kind, size) = match header.e_machine(endian) {
elf::EM_AARCH64 => {
if header.is_type_64() {
match reloc.r_type(endian, false) {
elf::R_AARCH64_ABS64 => (RelocationKind::Absolute, 64),
elf::R_AARCH64_ABS32 => (RelocationKind::Absolute, 32),
elf::R_AARCH64_ABS16 => (RelocationKind::Absolute, 16),
elf::R_AARCH64_PREL64 => (RelocationKind::Relative, 64),
elf::R_AARCH64_PREL32 => (RelocationKind::Relative, 32),
elf::R_AARCH64_PREL16 => (RelocationKind::Relative, 16),
elf::R_AARCH64_CALL26 => {
encoding = RelocationEncoding::AArch64Call;
(RelocationKind::PltRelative, 26)
}
r_type => (RelocationKind::Elf(r_type), 0),
}
} else {
match reloc.r_type(endian, false) {
elf::R_AARCH64_P32_ABS32 => (RelocationKind::Absolute, 32),
r_type => (RelocationKind::Elf(r_type), 0),
}
}
}
elf::EM_ARM => match reloc.r_type(endian, false) {
elf::R_ARM_ABS32 => (RelocationKind::Absolute, 32),
r_type => (RelocationKind::Elf(r_type), 0),
},
elf::EM_AVR => match reloc.r_type(endian, false) {
elf::R_AVR_32 => (RelocationKind::Absolute, 32),
elf::R_AVR_16 => (RelocationKind::Absolute, 16),
r_type => (RelocationKind::Elf(r_type), 0),
},
elf::EM_BPF => match reloc.r_type(endian, false) {
elf::R_BPF_64_64 => (RelocationKind::Absolute, 64),
elf::R_BPF_64_32 => (RelocationKind::Absolute, 32),
r_type => (RelocationKind::Elf(r_type), 0),
},
elf::EM_CSKY => match reloc.r_type(endian, false) {
elf::R_CKCORE_ADDR32 => (RelocationKind::Absolute, 32),
elf::R_CKCORE_PCREL32 => (RelocationKind::Relative, 32),
r_type => (RelocationKind::Elf(r_type), 0),
},
elf::EM_386 => match reloc.r_type(endian, false) {
elf::R_386_32 => (RelocationKind::Absolute, 32),
elf::R_386_PC32 => (RelocationKind::Relative, 32),
elf::R_386_GOT32 => (RelocationKind::Got, 32),
elf::R_386_PLT32 => (RelocationKind::PltRelative, 32),
elf::R_386_GOTOFF => (RelocationKind::GotBaseOffset, 32),
elf::R_386_GOTPC => (RelocationKind::GotBaseRelative, 32),
elf::R_386_16 => (RelocationKind::Absolute, 16),
elf::R_386_PC16 => (RelocationKind::Relative, 16),
elf::R_386_8 => (RelocationKind::Absolute, 8),
elf::R_386_PC8 => (RelocationKind::Relative, 8),
r_type => (RelocationKind::Elf(r_type), 0),
},
elf::EM_X86_64 => match reloc.r_type(endian, false) {
elf::R_X86_64_64 => (RelocationKind::Absolute, 64),
elf::R_X86_64_PC32 => (RelocationKind::Relative, 32),
elf::R_X86_64_GOT32 => (RelocationKind::Got, 32),
elf::R_X86_64_PLT32 => (RelocationKind::PltRelative, 32),
elf::R_X86_64_GOTPCREL => (RelocationKind::GotRelative, 32),
elf::R_X86_64_32 => (RelocationKind::Absolute, 32),
elf::R_X86_64_32S => {
encoding = RelocationEncoding::X86Signed;
(RelocationKind::Absolute, 32)
}
elf::R_X86_64_16 => (RelocationKind::Absolute, 16),
elf::R_X86_64_PC16 => (RelocationKind::Relative, 16),
elf::R_X86_64_8 => (RelocationKind::Absolute, 8),
elf::R_X86_64_PC8 => (RelocationKind::Relative, 8),
r_type => (RelocationKind::Elf(r_type), 0),
},
elf::EM_HEXAGON => match reloc.r_type(endian, false) {
elf::R_HEX_32 => (RelocationKind::Absolute, 32),
r_type => (RelocationKind::Elf(r_type), 0),
},
elf::EM_LOONGARCH => match reloc.r_type(endian, false) {
elf::R_LARCH_32 => (RelocationKind::Absolute, 32),
elf::R_LARCH_64 => (RelocationKind::Absolute, 64),
elf::R_LARCH_32_PCREL => (RelocationKind::Relative, 32),
elf::R_LARCH_B16 => {
encoding = RelocationEncoding::LoongArchBranch;
(RelocationKind::Relative, 16)
}
elf::R_LARCH_B21 => {
encoding = RelocationEncoding::LoongArchBranch;
(RelocationKind::Relative, 21)
}
elf::R_LARCH_B26 => {
encoding = RelocationEncoding::LoongArchBranch;
(RelocationKind::Relative, 26)
}
r_type => (RelocationKind::Elf(r_type), 0),
},
elf::EM_MIPS => match reloc.r_type(endian, is_mips64el) {
elf::R_MIPS_16 => (RelocationKind::Absolute, 16),
elf::R_MIPS_32 => (RelocationKind::Absolute, 32),
elf::R_MIPS_64 => (RelocationKind::Absolute, 64),
r_type => (RelocationKind::Elf(r_type), 0),
},
elf::EM_MSP430 => match reloc.r_type(endian, false) {
elf::R_MSP430_32 => (RelocationKind::Absolute, 32),
elf::R_MSP430_16_BYTE => (RelocationKind::Absolute, 16),
r_type => (RelocationKind::Elf(r_type), 0),
},
elf::EM_PPC => match reloc.r_type(endian, false) {
elf::R_PPC_ADDR32 => (RelocationKind::Absolute, 32),
r_type => (RelocationKind::Elf(r_type), 0),
},
elf::EM_PPC64 => match reloc.r_type(endian, false) {
elf::R_PPC64_ADDR32 => (RelocationKind::Absolute, 32),
elf::R_PPC64_ADDR64 => (RelocationKind::Absolute, 64),
r_type => (RelocationKind::Elf(r_type), 0),
},
elf::EM_RISCV => match reloc.r_type(endian, false) {
elf::R_RISCV_32 => (RelocationKind::Absolute, 32),
elf::R_RISCV_64 => (RelocationKind::Absolute, 64),
r_type => (RelocationKind::Elf(r_type), 0),
},
elf::EM_S390 => match reloc.r_type(endian, false) {
elf::R_390_8 => (RelocationKind::Absolute, 8),
elf::R_390_16 => (RelocationKind::Absolute, 16),
elf::R_390_32 => (RelocationKind::Absolute, 32),
elf::R_390_64 => (RelocationKind::Absolute, 64),
elf::R_390_PC16 => (RelocationKind::Relative, 16),
elf::R_390_PC32 => (RelocationKind::Relative, 32),
elf::R_390_PC64 => (RelocationKind::Relative, 64),
elf::R_390_PC16DBL => {
encoding = RelocationEncoding::S390xDbl;
(RelocationKind::Relative, 16)
}
elf::R_390_PC32DBL => {
encoding = RelocationEncoding::S390xDbl;
(RelocationKind::Relative, 32)
}
elf::R_390_PLT16DBL => {
encoding = RelocationEncoding::S390xDbl;
(RelocationKind::PltRelative, 16)
}
elf::R_390_PLT32DBL => {
encoding = RelocationEncoding::S390xDbl;
(RelocationKind::PltRelative, 32)
}
elf::R_390_GOT16 => (RelocationKind::Got, 16),
elf::R_390_GOT32 => (RelocationKind::Got, 32),
elf::R_390_GOT64 => (RelocationKind::Got, 64),
elf::R_390_GOTENT => {
encoding = RelocationEncoding::S390xDbl;
(RelocationKind::GotRelative, 32)
}
elf::R_390_GOTOFF16 => (RelocationKind::GotBaseOffset, 16),
elf::R_390_GOTOFF32 => (RelocationKind::GotBaseOffset, 32),
elf::R_390_GOTOFF64 => (RelocationKind::GotBaseOffset, 64),
elf::R_390_GOTPC => (RelocationKind::GotBaseRelative, 64),
elf::R_390_GOTPCDBL => {
encoding = RelocationEncoding::S390xDbl;
(RelocationKind::GotBaseRelative, 32)
}
r_type => (RelocationKind::Elf(r_type), 0),
},
elf::EM_SBF => match reloc.r_type(endian, false) {
elf::R_SBF_64_64 => (RelocationKind::Absolute, 64),
elf::R_SBF_64_32 => (RelocationKind::Absolute, 32),
r_type => (RelocationKind::Elf(r_type), 0),
},
elf::EM_SPARC | elf::EM_SPARC32PLUS | elf::EM_SPARCV9 => {
match reloc.r_type(endian, false) {
elf::R_SPARC_32 | elf::R_SPARC_UA32 => (RelocationKind::Absolute, 32),
elf::R_SPARC_64 | elf::R_SPARC_UA64 => (RelocationKind::Absolute, 64),
r_type => (RelocationKind::Elf(r_type), 0),
}
}
elf::EM_XTENSA => match reloc.r_type(endian, false) {
elf::R_XTENSA_32 => (RelocationKind::Absolute, 32),
elf::R_XTENSA_32_PCREL => (RelocationKind::Relative, 32),
r_type => (RelocationKind::Elf(r_type), 0),
},
_ => (RelocationKind::Elf(reloc.r_type(endian, false)), 0),
};
let sym = reloc.r_sym(endian, is_mips64el) as usize;
let target = if sym == 0 {
RelocationTarget::Absolute
} else {
RelocationTarget::Symbol(SymbolIndex(sym))
};
Relocation {
kind,
encoding,
size,
target,
addend: reloc.r_addend(endian).into(),
implicit_addend,
}
}
/// A trait for generic access to `Rel32` and `Rel64`.
#[allow(missing_docs)]
pub trait Rel: Debug + Pod + Clone {
type Word: Into<u64>;
type Sword: Into<i64>;
type Endian: endian::Endian;
fn r_offset(&self, endian: Self::Endian) -> Self::Word;
fn r_info(&self, endian: Self::Endian) -> Self::Word;
fn r_sym(&self, endian: Self::Endian) -> u32;
fn r_type(&self, endian: Self::Endian) -> u32;
}
impl<Endian: endian::Endian> Rel for elf::Rel32<Endian> {
type Word = u32;
type Sword = i32;
type Endian = Endian;
#[inline]
fn r_offset(&self, endian: Self::Endian) -> Self::Word {
self.r_offset.get(endian)
}
#[inline]
fn r_info(&self, endian: Self::Endian) -> Self::Word {
self.r_info.get(endian)
}
#[inline]
fn r_sym(&self, endian: Self::Endian) -> u32 {
self.r_sym(endian)
}
#[inline]
fn r_type(&self, endian: Self::Endian) -> u32 {
self.r_type(endian)
}
}
impl<Endian: endian::Endian> Rel for elf::Rel64<Endian> {
type Word = u64;
type Sword = i64;
type Endian = Endian;
#[inline]
fn r_offset(&self, endian: Self::Endian) -> Self::Word {
self.r_offset.get(endian)
}
#[inline]
fn r_info(&self, endian: Self::Endian) -> Self::Word {
self.r_info.get(endian)
}
#[inline]
fn r_sym(&self, endian: Self::Endian) -> u32 {
self.r_sym(endian)
}
#[inline]
fn r_type(&self, endian: Self::Endian) -> u32 {
self.r_type(endian)
}
}
/// A trait for generic access to `Rela32` and `Rela64`.
#[allow(missing_docs)]
pub trait Rela: Debug + Pod + Clone {
type Word: Into<u64>;
type Sword: Into<i64>;
type Endian: endian::Endian;
fn r_offset(&self, endian: Self::Endian) -> Self::Word;
fn r_info(&self, endian: Self::Endian, is_mips64el: bool) -> Self::Word;
fn r_addend(&self, endian: Self::Endian) -> Self::Sword;
fn r_sym(&self, endian: Self::Endian, is_mips64el: bool) -> u32;
fn r_type(&self, endian: Self::Endian, is_mips64el: bool) -> u32;
}
impl<Endian: endian::Endian> Rela for elf::Rela32<Endian> {
type Word = u32;
type Sword = i32;
type Endian = Endian;
#[inline]
fn r_offset(&self, endian: Self::Endian) -> Self::Word {
self.r_offset.get(endian)
}
#[inline]
fn r_info(&self, endian: Self::Endian, _is_mips64el: bool) -> Self::Word {
self.r_info.get(endian)
}
#[inline]
fn r_addend(&self, endian: Self::Endian) -> Self::Sword {
self.r_addend.get(endian)
}
#[inline]
fn r_sym(&self, endian: Self::Endian, _is_mips64el: bool) -> u32 {
self.r_sym(endian)
}
#[inline]
fn r_type(&self, endian: Self::Endian, _is_mips64el: bool) -> u32 {
self.r_type(endian)
}
}
impl<Endian: endian::Endian> Rela for elf::Rela64<Endian> {
type Word = u64;
type Sword = i64;
type Endian = Endian;
#[inline]
fn r_offset(&self, endian: Self::Endian) -> Self::Word {
self.r_offset.get(endian)
}
#[inline]
fn r_info(&self, endian: Self::Endian, is_mips64el: bool) -> Self::Word {
self.get_r_info(endian, is_mips64el)
}
#[inline]
fn r_addend(&self, endian: Self::Endian) -> Self::Sword {
self.r_addend.get(endian)
}
#[inline]
fn r_sym(&self, endian: Self::Endian, is_mips64el: bool) -> u32 {
self.r_sym(endian, is_mips64el)
}
#[inline]
fn r_type(&self, endian: Self::Endian, is_mips64el: bool) -> u32 {
self.r_type(endian, is_mips64el)
}
}