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use alloc::vec::Vec;
use core::fmt::Debug;
use core::{mem, str};
use crate::read::{
self, Architecture, ComdatKind, Error, Export, FileFlags, Import, NoDynamicRelocationIterator,
Object, ObjectComdat, ObjectKind, ObjectMap, ObjectSection, ReadError, ReadRef, Result,
SectionIndex, SymbolIndex,
};
use crate::{endian, macho, BigEndian, ByteString, Endian, Endianness, Pod};
use super::{
DyldCacheImage, LoadCommandIterator, MachOSection, MachOSectionInternal, MachOSectionIterator,
MachOSegment, MachOSegmentInternal, MachOSegmentIterator, MachOSymbol, MachOSymbolIterator,
MachOSymbolTable, Nlist, Section, Segment, SymbolTable,
};
/// A 32-bit Mach-O object file.
pub type MachOFile32<'data, Endian = Endianness, R = &'data [u8]> =
MachOFile<'data, macho::MachHeader32<Endian>, R>;
/// A 64-bit Mach-O object file.
pub type MachOFile64<'data, Endian = Endianness, R = &'data [u8]> =
MachOFile<'data, macho::MachHeader64<Endian>, R>;
/// A partially parsed Mach-O file.
///
/// Most of the functionality of this type is provided by the `Object` trait implementation.
#[derive(Debug)]
pub struct MachOFile<'data, Mach, R = &'data [u8]>
where
Mach: MachHeader,
R: ReadRef<'data>,
{
pub(super) endian: Mach::Endian,
pub(super) data: R,
pub(super) header_offset: u64,
pub(super) header: &'data Mach,
pub(super) segments: Vec<MachOSegmentInternal<'data, Mach, R>>,
pub(super) sections: Vec<MachOSectionInternal<'data, Mach>>,
pub(super) symbols: SymbolTable<'data, Mach, R>,
}
impl<'data, Mach, R> MachOFile<'data, Mach, R>
where
Mach: MachHeader,
R: ReadRef<'data>,
{
/// Parse the raw Mach-O file data.
pub fn parse(data: R) -> Result<Self> {
let header = Mach::parse(data, 0)?;
let endian = header.endian()?;
// Build a list of segments and sections to make some operations more efficient.
let mut segments = Vec::new();
let mut sections = Vec::new();
let mut symbols = SymbolTable::default();
if let Ok(mut commands) = header.load_commands(endian, data, 0) {
while let Ok(Some(command)) = commands.next() {
if let Some((segment, section_data)) = Mach::Segment::from_command(command)? {
let segment_index = segments.len();
segments.push(MachOSegmentInternal { segment, data });
for section in segment.sections(endian, section_data)? {
let index = SectionIndex(sections.len() + 1);
sections.push(MachOSectionInternal::parse(index, segment_index, section));
}
} else if let Some(symtab) = command.symtab()? {
symbols = symtab.symbols(endian, data)?;
}
}
}
Ok(MachOFile {
endian,
data,
header_offset: 0,
header,
segments,
sections,
symbols,
})
}
/// Parse the Mach-O file for the given image from the dyld shared cache.
/// This will read different sections from different subcaches, if necessary.
pub fn parse_dyld_cache_image<'cache, E: Endian>(
image: &DyldCacheImage<'data, 'cache, E, R>,
) -> Result<Self> {
let (data, header_offset) = image.image_data_and_offset()?;
let header = Mach::parse(data, header_offset)?;
let endian = header.endian()?;
// Build a list of sections to make some operations more efficient.
// Also build a list of segments, because we need to remember which ReadRef
// to read each section's data from. Only the DyldCache knows this information,
// and we won't have access to it once we've exited this function.
let mut segments = Vec::new();
let mut sections = Vec::new();
let mut linkedit_data: Option<R> = None;
let mut symtab = None;
if let Ok(mut commands) = header.load_commands(endian, data, header_offset) {
while let Ok(Some(command)) = commands.next() {
if let Some((segment, section_data)) = Mach::Segment::from_command(command)? {
// Each segment can be stored in a different subcache. Get the segment's
// address and look it up in the cache mappings, to find the correct cache data.
let addr = segment.vmaddr(endian).into();
let (data, _offset) = image
.cache
.data_and_offset_for_address(addr)
.read_error("Could not find segment data in dyld shared cache")?;
if segment.name() == macho::SEG_LINKEDIT.as_bytes() {
linkedit_data = Some(data);
}
let segment_index = segments.len();
segments.push(MachOSegmentInternal { segment, data });
for section in segment.sections(endian, section_data)? {
let index = SectionIndex(sections.len() + 1);
sections.push(MachOSectionInternal::parse(index, segment_index, section));
}
} else if let Some(st) = command.symtab()? {
symtab = Some(st);
}
}
}
// The symbols are found in the __LINKEDIT segment, so make sure to read them from the
// correct subcache.
let symbols = match (symtab, linkedit_data) {
(Some(symtab), Some(linkedit_data)) => symtab.symbols(endian, linkedit_data)?,
_ => SymbolTable::default(),
};
Ok(MachOFile {
endian,
data,
header_offset,
header,
segments,
sections,
symbols,
})
}
/// Return the section at the given index.
#[inline]
pub(super) fn section_internal(
&self,
index: SectionIndex,
) -> Result<&MachOSectionInternal<'data, Mach>> {
index
.0
.checked_sub(1)
.and_then(|index| self.sections.get(index))
.read_error("Invalid Mach-O section index")
}
pub(super) fn segment_internal(
&self,
index: usize,
) -> Result<&MachOSegmentInternal<'data, Mach, R>> {
self.segments
.get(index)
.read_error("Invalid Mach-O segment index")
}
}
impl<'data, Mach, R> read::private::Sealed for MachOFile<'data, Mach, R>
where
Mach: MachHeader,
R: ReadRef<'data>,
{
}
impl<'data, 'file, Mach, R> Object<'data, 'file> for MachOFile<'data, Mach, R>
where
'data: 'file,
Mach: MachHeader,
R: 'file + ReadRef<'data>,
{
type Segment = MachOSegment<'data, 'file, Mach, R>;
type SegmentIterator = MachOSegmentIterator<'data, 'file, Mach, R>;
type Section = MachOSection<'data, 'file, Mach, R>;
type SectionIterator = MachOSectionIterator<'data, 'file, Mach, R>;
type Comdat = MachOComdat<'data, 'file, Mach, R>;
type ComdatIterator = MachOComdatIterator<'data, 'file, Mach, R>;
type Symbol = MachOSymbol<'data, 'file, Mach, R>;
type SymbolIterator = MachOSymbolIterator<'data, 'file, Mach, R>;
type SymbolTable = MachOSymbolTable<'data, 'file, Mach, R>;
type DynamicRelocationIterator = NoDynamicRelocationIterator;
fn architecture(&self) -> Architecture {
match self.header.cputype(self.endian) {
macho::CPU_TYPE_ARM => Architecture::Arm,
macho::CPU_TYPE_ARM64 => Architecture::Aarch64,
macho::CPU_TYPE_ARM64_32 => Architecture::Aarch64_Ilp32,
macho::CPU_TYPE_X86 => Architecture::I386,
macho::CPU_TYPE_X86_64 => Architecture::X86_64,
macho::CPU_TYPE_MIPS => Architecture::Mips,
macho::CPU_TYPE_POWERPC => Architecture::PowerPc,
macho::CPU_TYPE_POWERPC64 => Architecture::PowerPc64,
_ => Architecture::Unknown,
}
}
#[inline]
fn is_little_endian(&self) -> bool {
self.header.is_little_endian()
}
#[inline]
fn is_64(&self) -> bool {
self.header.is_type_64()
}
fn kind(&self) -> ObjectKind {
match self.header.filetype(self.endian) {
macho::MH_OBJECT => ObjectKind::Relocatable,
macho::MH_EXECUTE => ObjectKind::Executable,
macho::MH_CORE => ObjectKind::Core,
macho::MH_DYLIB => ObjectKind::Dynamic,
_ => ObjectKind::Unknown,
}
}
fn segments(&'file self) -> MachOSegmentIterator<'data, 'file, Mach, R> {
MachOSegmentIterator {
file: self,
iter: self.segments.iter(),
}
}
fn section_by_name_bytes(
&'file self,
section_name: &[u8],
) -> Option<MachOSection<'data, 'file, Mach, R>> {
// Translate the "." prefix to the "__" prefix used by OSX/Mach-O, eg
// ".debug_info" to "__debug_info", and limit to 16 bytes total.
let system_name = if section_name.starts_with(b".") {
if section_name.len() > 15 {
Some(§ion_name[1..15])
} else {
Some(§ion_name[1..])
}
} else {
None
};
let cmp_section_name = |section: &MachOSection<'data, 'file, Mach, R>| {
section
.name_bytes()
.map(|name| {
section_name == name
|| system_name
.filter(|system_name| {
name.starts_with(b"__") && name[2..] == **system_name
})
.is_some()
})
.unwrap_or(false)
};
self.sections().find(cmp_section_name)
}
fn section_by_index(
&'file self,
index: SectionIndex,
) -> Result<MachOSection<'data, 'file, Mach, R>> {
let internal = *self.section_internal(index)?;
Ok(MachOSection {
file: self,
internal,
})
}
fn sections(&'file self) -> MachOSectionIterator<'data, 'file, Mach, R> {
MachOSectionIterator {
file: self,
iter: self.sections.iter(),
}
}
fn comdats(&'file self) -> MachOComdatIterator<'data, 'file, Mach, R> {
MachOComdatIterator { file: self }
}
fn symbol_by_index(
&'file self,
index: SymbolIndex,
) -> Result<MachOSymbol<'data, 'file, Mach, R>> {
let nlist = self.symbols.symbol(index.0)?;
MachOSymbol::new(self, index, nlist).read_error("Unsupported Mach-O symbol index")
}
fn symbols(&'file self) -> MachOSymbolIterator<'data, 'file, Mach, R> {
MachOSymbolIterator {
file: self,
index: 0,
}
}
#[inline]
fn symbol_table(&'file self) -> Option<MachOSymbolTable<'data, 'file, Mach, R>> {
Some(MachOSymbolTable { file: self })
}
fn dynamic_symbols(&'file self) -> MachOSymbolIterator<'data, 'file, Mach, R> {
MachOSymbolIterator {
file: self,
index: self.symbols.len(),
}
}
#[inline]
fn dynamic_symbol_table(&'file self) -> Option<MachOSymbolTable<'data, 'file, Mach, R>> {
None
}
fn object_map(&'file self) -> ObjectMap<'data> {
self.symbols.object_map(self.endian)
}
fn imports(&self) -> Result<Vec<Import<'data>>> {
let mut dysymtab = None;
let mut libraries = Vec::new();
let twolevel = self.header.flags(self.endian) & macho::MH_TWOLEVEL != 0;
if twolevel {
libraries.push(&[][..]);
}
let mut commands = self
.header
.load_commands(self.endian, self.data, self.header_offset)?;
while let Some(command) = commands.next()? {
if let Some(command) = command.dysymtab()? {
dysymtab = Some(command);
}
if twolevel {
if let Some(dylib) = command.dylib()? {
libraries.push(command.string(self.endian, dylib.dylib.name)?);
}
}
}
let mut imports = Vec::new();
if let Some(dysymtab) = dysymtab {
let index = dysymtab.iundefsym.get(self.endian) as usize;
let number = dysymtab.nundefsym.get(self.endian) as usize;
for i in index..(index.wrapping_add(number)) {
let symbol = self.symbols.symbol(i)?;
let name = symbol.name(self.endian, self.symbols.strings())?;
let library = if twolevel {
libraries
.get(symbol.library_ordinal(self.endian) as usize)
.copied()
.read_error("Invalid Mach-O symbol library ordinal")?
} else {
&[]
};
imports.push(Import {
name: ByteString(name),
library: ByteString(library),
});
}
}
Ok(imports)
}
fn exports(&self) -> Result<Vec<Export<'data>>> {
let mut dysymtab = None;
let mut commands = self
.header
.load_commands(self.endian, self.data, self.header_offset)?;
while let Some(command) = commands.next()? {
if let Some(command) = command.dysymtab()? {
dysymtab = Some(command);
break;
}
}
let mut exports = Vec::new();
if let Some(dysymtab) = dysymtab {
let index = dysymtab.iextdefsym.get(self.endian) as usize;
let number = dysymtab.nextdefsym.get(self.endian) as usize;
for i in index..(index.wrapping_add(number)) {
let symbol = self.symbols.symbol(i)?;
let name = symbol.name(self.endian, self.symbols.strings())?;
let address = symbol.n_value(self.endian).into();
exports.push(Export {
name: ByteString(name),
address,
});
}
}
Ok(exports)
}
#[inline]
fn dynamic_relocations(&'file self) -> Option<NoDynamicRelocationIterator> {
None
}
fn has_debug_symbols(&self) -> bool {
self.section_by_name(".debug_info").is_some()
}
fn mach_uuid(&self) -> Result<Option<[u8; 16]>> {
self.header.uuid(self.endian, self.data, self.header_offset)
}
fn relative_address_base(&self) -> u64 {
0
}
fn entry(&self) -> u64 {
if let Ok(mut commands) =
self.header
.load_commands(self.endian, self.data, self.header_offset)
{
while let Ok(Some(command)) = commands.next() {
if let Ok(Some(command)) = command.entry_point() {
return command.entryoff.get(self.endian);
}
}
}
0
}
fn flags(&self) -> FileFlags {
FileFlags::MachO {
flags: self.header.flags(self.endian),
}
}
}
/// An iterator over the COMDAT section groups of a `MachOFile64`.
pub type MachOComdatIterator32<'data, 'file, Endian = Endianness, R = &'data [u8]> =
MachOComdatIterator<'data, 'file, macho::MachHeader32<Endian>, R>;
/// An iterator over the COMDAT section groups of a `MachOFile64`.
pub type MachOComdatIterator64<'data, 'file, Endian = Endianness, R = &'data [u8]> =
MachOComdatIterator<'data, 'file, macho::MachHeader64<Endian>, R>;
/// An iterator over the COMDAT section groups of a `MachOFile`.
#[derive(Debug)]
pub struct MachOComdatIterator<'data, 'file, Mach, R = &'data [u8]>
where
Mach: MachHeader,
R: ReadRef<'data>,
{
#[allow(unused)]
file: &'file MachOFile<'data, Mach, R>,
}
impl<'data, 'file, Mach, R> Iterator for MachOComdatIterator<'data, 'file, Mach, R>
where
Mach: MachHeader,
R: ReadRef<'data>,
{
type Item = MachOComdat<'data, 'file, Mach, R>;
#[inline]
fn next(&mut self) -> Option<Self::Item> {
None
}
}
/// A COMDAT section group of a `MachOFile32`.
pub type MachOComdat32<'data, 'file, Endian = Endianness, R = &'data [u8]> =
MachOComdat<'data, 'file, macho::MachHeader32<Endian>, R>;
/// A COMDAT section group of a `MachOFile64`.
pub type MachOComdat64<'data, 'file, Endian = Endianness, R = &'data [u8]> =
MachOComdat<'data, 'file, macho::MachHeader64<Endian>, R>;
/// A COMDAT section group of a `MachOFile`.
#[derive(Debug)]
pub struct MachOComdat<'data, 'file, Mach, R = &'data [u8]>
where
Mach: MachHeader,
R: ReadRef<'data>,
{
#[allow(unused)]
file: &'file MachOFile<'data, Mach, R>,
}
impl<'data, 'file, Mach, R> read::private::Sealed for MachOComdat<'data, 'file, Mach, R>
where
Mach: MachHeader,
R: ReadRef<'data>,
{
}
impl<'data, 'file, Mach, R> ObjectComdat<'data> for MachOComdat<'data, 'file, Mach, R>
where
Mach: MachHeader,
R: ReadRef<'data>,
{
type SectionIterator = MachOComdatSectionIterator<'data, 'file, Mach, R>;
#[inline]
fn kind(&self) -> ComdatKind {
unreachable!();
}
#[inline]
fn symbol(&self) -> SymbolIndex {
unreachable!();
}
#[inline]
fn name_bytes(&self) -> Result<&[u8]> {
unreachable!();
}
#[inline]
fn name(&self) -> Result<&str> {
unreachable!();
}
#[inline]
fn sections(&self) -> Self::SectionIterator {
unreachable!();
}
}
/// An iterator over the sections in a COMDAT section group of a `MachOFile32`.
pub type MachOComdatSectionIterator32<'data, 'file, Endian = Endianness, R = &'data [u8]> =
MachOComdatSectionIterator<'data, 'file, macho::MachHeader32<Endian>, R>;
/// An iterator over the sections in a COMDAT section group of a `MachOFile64`.
pub type MachOComdatSectionIterator64<'data, 'file, Endian = Endianness, R = &'data [u8]> =
MachOComdatSectionIterator<'data, 'file, macho::MachHeader64<Endian>, R>;
/// An iterator over the sections in a COMDAT section group of a `MachOFile`.
#[derive(Debug)]
pub struct MachOComdatSectionIterator<'data, 'file, Mach, R = &'data [u8]>
where
Mach: MachHeader,
R: ReadRef<'data>,
{
#[allow(unused)]
file: &'file MachOFile<'data, Mach, R>,
}
impl<'data, 'file, Mach, R> Iterator for MachOComdatSectionIterator<'data, 'file, Mach, R>
where
Mach: MachHeader,
R: ReadRef<'data>,
{
type Item = SectionIndex;
fn next(&mut self) -> Option<Self::Item> {
None
}
}
/// A trait for generic access to `MachHeader32` and `MachHeader64`.
#[allow(missing_docs)]
pub trait MachHeader: Debug + Pod {
type Word: Into<u64>;
type Endian: endian::Endian;
type Segment: Segment<Endian = Self::Endian, Section = Self::Section>;
type Section: Section<Endian = Self::Endian>;
type Nlist: Nlist<Endian = Self::Endian>;
/// Return true if this type is a 64-bit header.
///
/// This is a property of the type, not a value in the header data.
fn is_type_64(&self) -> bool;
/// Return true if the `magic` field signifies big-endian.
fn is_big_endian(&self) -> bool;
/// Return true if the `magic` field signifies little-endian.
fn is_little_endian(&self) -> bool;
fn magic(&self) -> u32;
fn cputype(&self, endian: Self::Endian) -> u32;
fn cpusubtype(&self, endian: Self::Endian) -> u32;
fn filetype(&self, endian: Self::Endian) -> u32;
fn ncmds(&self, endian: Self::Endian) -> u32;
fn sizeofcmds(&self, endian: Self::Endian) -> u32;
fn flags(&self, endian: Self::Endian) -> u32;
// Provided methods.
/// Read the file header.
///
/// Also checks that the magic field in the file header is a supported format.
fn parse<'data, R: ReadRef<'data>>(data: R, offset: u64) -> read::Result<&'data Self> {
let header = data
.read_at::<Self>(offset)
.read_error("Invalid Mach-O header size or alignment")?;
if !header.is_supported() {
return Err(Error("Unsupported Mach-O header"));
}
Ok(header)
}
fn is_supported(&self) -> bool {
self.is_little_endian() || self.is_big_endian()
}
fn endian(&self) -> Result<Self::Endian> {
Self::Endian::from_big_endian(self.is_big_endian()).read_error("Unsupported Mach-O endian")
}
fn load_commands<'data, R: ReadRef<'data>>(
&self,
endian: Self::Endian,
data: R,
header_offset: u64,
) -> Result<LoadCommandIterator<'data, Self::Endian>> {
let data = data
.read_bytes_at(
header_offset + mem::size_of::<Self>() as u64,
self.sizeofcmds(endian).into(),
)
.read_error("Invalid Mach-O load command table size")?;
Ok(LoadCommandIterator::new(endian, data, self.ncmds(endian)))
}
/// Return the UUID from the `LC_UUID` load command, if one is present.
fn uuid<'data, R: ReadRef<'data>>(
&self,
endian: Self::Endian,
data: R,
header_offset: u64,
) -> Result<Option<[u8; 16]>> {
let mut commands = self.load_commands(endian, data, header_offset)?;
while let Some(command) = commands.next()? {
if let Ok(Some(uuid)) = command.uuid() {
return Ok(Some(uuid.uuid));
}
}
Ok(None)
}
}
impl<Endian: endian::Endian> MachHeader for macho::MachHeader32<Endian> {
type Word = u32;
type Endian = Endian;
type Segment = macho::SegmentCommand32<Endian>;
type Section = macho::Section32<Endian>;
type Nlist = macho::Nlist32<Endian>;
fn is_type_64(&self) -> bool {
false
}
fn is_big_endian(&self) -> bool {
self.magic() == macho::MH_MAGIC
}
fn is_little_endian(&self) -> bool {
self.magic() == macho::MH_CIGAM
}
fn magic(&self) -> u32 {
self.magic.get(BigEndian)
}
fn cputype(&self, endian: Self::Endian) -> u32 {
self.cputype.get(endian)
}
fn cpusubtype(&self, endian: Self::Endian) -> u32 {
self.cpusubtype.get(endian)
}
fn filetype(&self, endian: Self::Endian) -> u32 {
self.filetype.get(endian)
}
fn ncmds(&self, endian: Self::Endian) -> u32 {
self.ncmds.get(endian)
}
fn sizeofcmds(&self, endian: Self::Endian) -> u32 {
self.sizeofcmds.get(endian)
}
fn flags(&self, endian: Self::Endian) -> u32 {
self.flags.get(endian)
}
}
impl<Endian: endian::Endian> MachHeader for macho::MachHeader64<Endian> {
type Word = u64;
type Endian = Endian;
type Segment = macho::SegmentCommand64<Endian>;
type Section = macho::Section64<Endian>;
type Nlist = macho::Nlist64<Endian>;
fn is_type_64(&self) -> bool {
true
}
fn is_big_endian(&self) -> bool {
self.magic() == macho::MH_MAGIC_64
}
fn is_little_endian(&self) -> bool {
self.magic() == macho::MH_CIGAM_64
}
fn magic(&self) -> u32 {
self.magic.get(BigEndian)
}
fn cputype(&self, endian: Self::Endian) -> u32 {
self.cputype.get(endian)
}
fn cpusubtype(&self, endian: Self::Endian) -> u32 {
self.cpusubtype.get(endian)
}
fn filetype(&self, endian: Self::Endian) -> u32 {
self.filetype.get(endian)
}
fn ncmds(&self, endian: Self::Endian) -> u32 {
self.ncmds.get(endian)
}
fn sizeofcmds(&self, endian: Self::Endian) -> u32 {
self.sizeofcmds.get(endian)
}
fn flags(&self, endian: Self::Endian) -> u32 {
self.flags.get(endian)
}
}