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use alloc::vec::Vec;
use core::fmt::Debug;
use core::{fmt, slice, str};
use crate::endian::{self, Endianness};
use crate::macho;
use crate::pod::Pod;
use crate::read::util::StringTable;
use crate::read::{
self, ObjectMap, ObjectMapEntry, ObjectMapFile, ObjectSymbol, ObjectSymbolTable, ReadError,
ReadRef, Result, SectionIndex, SectionKind, SymbolFlags, SymbolIndex, SymbolKind, SymbolMap,
SymbolMapEntry, SymbolScope, SymbolSection,
};
use super::{MachHeader, MachOFile};
/// A table of symbol entries in a Mach-O file.
///
/// Also includes the string table used for the symbol names.
///
/// Returned by [`macho::SymtabCommand::symbols`].
#[derive(Debug, Clone, Copy)]
pub struct SymbolTable<'data, Mach: MachHeader, R = &'data [u8]>
where
R: ReadRef<'data>,
{
symbols: &'data [Mach::Nlist],
strings: StringTable<'data, R>,
}
impl<'data, Mach: MachHeader, R: ReadRef<'data>> Default for SymbolTable<'data, Mach, R> {
fn default() -> Self {
SymbolTable {
symbols: &[],
strings: Default::default(),
}
}
}
impl<'data, Mach: MachHeader, R: ReadRef<'data>> SymbolTable<'data, Mach, R> {
#[inline]
pub(super) fn new(symbols: &'data [Mach::Nlist], strings: StringTable<'data, R>) -> Self {
SymbolTable { symbols, strings }
}
/// Return the string table used for the symbol names.
#[inline]
pub fn strings(&self) -> StringTable<'data, R> {
self.strings
}
/// Iterate over the symbols.
#[inline]
pub fn iter(&self) -> slice::Iter<'data, Mach::Nlist> {
self.symbols.iter()
}
/// Return true if the symbol table is empty.
#[inline]
pub fn is_empty(&self) -> bool {
self.symbols.is_empty()
}
/// The number of symbols.
#[inline]
pub fn len(&self) -> usize {
self.symbols.len()
}
/// Return the symbol at the given index.
pub fn symbol(&self, index: SymbolIndex) -> Result<&'data Mach::Nlist> {
self.symbols
.get(index.0)
.read_error("Invalid Mach-O symbol index")
}
/// Construct a map from addresses to a user-defined map entry.
pub fn map<Entry: SymbolMapEntry, F: Fn(&'data Mach::Nlist) -> Option<Entry>>(
&self,
f: F,
) -> SymbolMap<Entry> {
let mut symbols = Vec::new();
for nlist in self.symbols {
if !nlist.is_definition() {
continue;
}
if let Some(entry) = f(nlist) {
symbols.push(entry);
}
}
SymbolMap::new(symbols)
}
/// Construct a map from addresses to symbol names and object file names.
pub fn object_map(&self, endian: Mach::Endian) -> ObjectMap<'data> {
let mut symbols = Vec::new();
let mut objects = Vec::new();
let mut object = None;
let mut current_function = None;
// Each module starts with one or two N_SO symbols (path, or directory + filename)
// and one N_OSO symbol. The module is terminated by an empty N_SO symbol.
for nlist in self.symbols {
let n_type = nlist.n_type();
if n_type & macho::N_STAB == 0 {
continue;
}
// TODO: includes variables too (N_GSYM, N_STSYM). These may need to get their
// address from regular symbols though.
match n_type {
macho::N_SO => {
object = None;
}
macho::N_OSO => {
object = None;
if let Ok(name) = nlist.name(endian, self.strings) {
if !name.is_empty() {
object = Some(objects.len());
// `N_OSO` symbol names can be either `/path/to/object.o`
// or `/path/to/archive.a(object.o)`.
let (path, member) = name
.split_last()
.and_then(|(last, head)| {
if *last != b')' {
return None;
}
let index = head.iter().position(|&x| x == b'(')?;
let (archive, rest) = head.split_at(index);
Some((archive, Some(&rest[1..])))
})
.unwrap_or((name, None));
objects.push(ObjectMapFile::new(path, member));
}
}
}
macho::N_FUN => {
if let Ok(name) = nlist.name(endian, self.strings) {
if !name.is_empty() {
current_function = Some((name, nlist.n_value(endian).into()))
} else if let Some((name, address)) = current_function.take() {
if let Some(object) = object {
symbols.push(ObjectMapEntry {
address,
size: nlist.n_value(endian).into(),
name,
object,
});
}
}
}
}
_ => {}
}
}
ObjectMap {
symbols: SymbolMap::new(symbols),
objects,
}
}
}
/// A symbol table in a [`MachOFile32`](super::MachOFile32).
pub type MachOSymbolTable32<'data, 'file, Endian = Endianness, R = &'data [u8]> =
MachOSymbolTable<'data, 'file, macho::MachHeader32<Endian>, R>;
/// A symbol table in a [`MachOFile64`](super::MachOFile64).
pub type MachOSymbolTable64<'data, 'file, Endian = Endianness, R = &'data [u8]> =
MachOSymbolTable<'data, 'file, macho::MachHeader64<Endian>, R>;
/// A symbol table in a [`MachOFile`].
#[derive(Debug, Clone, Copy)]
pub struct MachOSymbolTable<'data, 'file, Mach, R = &'data [u8]>
where
Mach: MachHeader,
R: ReadRef<'data>,
{
pub(super) file: &'file MachOFile<'data, Mach, R>,
}
impl<'data, 'file, Mach, R> read::private::Sealed for MachOSymbolTable<'data, 'file, Mach, R>
where
Mach: MachHeader,
R: ReadRef<'data>,
{
}
impl<'data, 'file, Mach, R> ObjectSymbolTable<'data> for MachOSymbolTable<'data, 'file, Mach, R>
where
Mach: MachHeader,
R: ReadRef<'data>,
{
type Symbol = MachOSymbol<'data, 'file, Mach, R>;
type SymbolIterator = MachOSymbolIterator<'data, 'file, Mach, R>;
fn symbols(&self) -> Self::SymbolIterator {
MachOSymbolIterator::new(self.file)
}
fn symbol_by_index(&self, index: SymbolIndex) -> Result<Self::Symbol> {
let nlist = self.file.symbols.symbol(index)?;
MachOSymbol::new(self.file, index, nlist).read_error("Unsupported Mach-O symbol index")
}
}
/// An iterator for the symbols in a [`MachOFile32`](super::MachOFile32).
pub type MachOSymbolIterator32<'data, 'file, Endian = Endianness, R = &'data [u8]> =
MachOSymbolIterator<'data, 'file, macho::MachHeader32<Endian>, R>;
/// An iterator for the symbols in a [`MachOFile64`](super::MachOFile64).
pub type MachOSymbolIterator64<'data, 'file, Endian = Endianness, R = &'data [u8]> =
MachOSymbolIterator<'data, 'file, macho::MachHeader64<Endian>, R>;
/// An iterator for the symbols in a [`MachOFile`].
pub struct MachOSymbolIterator<'data, 'file, Mach, R = &'data [u8]>
where
Mach: MachHeader,
R: ReadRef<'data>,
{
file: &'file MachOFile<'data, Mach, R>,
index: SymbolIndex,
}
impl<'data, 'file, Mach, R> MachOSymbolIterator<'data, 'file, Mach, R>
where
Mach: MachHeader,
R: ReadRef<'data>,
{
pub(super) fn new(file: &'file MachOFile<'data, Mach, R>) -> Self {
MachOSymbolIterator {
file,
index: SymbolIndex(0),
}
}
pub(super) fn empty(file: &'file MachOFile<'data, Mach, R>) -> Self {
MachOSymbolIterator {
file,
index: SymbolIndex(file.symbols.len()),
}
}
}
impl<'data, 'file, Mach, R> fmt::Debug for MachOSymbolIterator<'data, 'file, Mach, R>
where
Mach: MachHeader,
R: ReadRef<'data>,
{
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_struct("MachOSymbolIterator").finish()
}
}
impl<'data, 'file, Mach, R> Iterator for MachOSymbolIterator<'data, 'file, Mach, R>
where
Mach: MachHeader,
R: ReadRef<'data>,
{
type Item = MachOSymbol<'data, 'file, Mach, R>;
fn next(&mut self) -> Option<Self::Item> {
loop {
let index = self.index;
let nlist = self.file.symbols.symbols.get(index.0)?;
self.index.0 += 1;
if let Some(symbol) = MachOSymbol::new(self.file, index, nlist) {
return Some(symbol);
}
}
}
}
/// A symbol in a [`MachOFile32`](super::MachOFile32).
pub type MachOSymbol32<'data, 'file, Endian = Endianness, R = &'data [u8]> =
MachOSymbol<'data, 'file, macho::MachHeader32<Endian>, R>;
/// A symbol in a [`MachOFile64`](super::MachOFile64).
pub type MachOSymbol64<'data, 'file, Endian = Endianness, R = &'data [u8]> =
MachOSymbol<'data, 'file, macho::MachHeader64<Endian>, R>;
/// A symbol in a [`MachOFile`].
///
/// Most functionality is provided by the [`ObjectSymbol`] trait implementation.
#[derive(Debug, Clone, Copy)]
pub struct MachOSymbol<'data, 'file, Mach, R = &'data [u8]>
where
Mach: MachHeader,
R: ReadRef<'data>,
{
file: &'file MachOFile<'data, Mach, R>,
index: SymbolIndex,
nlist: &'data Mach::Nlist,
}
impl<'data, 'file, Mach, R> MachOSymbol<'data, 'file, Mach, R>
where
Mach: MachHeader,
R: ReadRef<'data>,
{
pub(super) fn new(
file: &'file MachOFile<'data, Mach, R>,
index: SymbolIndex,
nlist: &'data Mach::Nlist,
) -> Option<Self> {
if nlist.n_type() & macho::N_STAB != 0 {
return None;
}
Some(MachOSymbol { file, index, nlist })
}
/// Get the Mach-O file containing this symbol.
pub fn macho_file(&self) -> &'file MachOFile<'data, Mach, R> {
self.file
}
/// Get the raw Mach-O symbol structure.
pub fn macho_symbol(&self) -> &'data Mach::Nlist {
self.nlist
}
}
impl<'data, 'file, Mach, R> read::private::Sealed for MachOSymbol<'data, 'file, Mach, R>
where
Mach: MachHeader,
R: ReadRef<'data>,
{
}
impl<'data, 'file, Mach, R> ObjectSymbol<'data> for MachOSymbol<'data, 'file, Mach, R>
where
Mach: MachHeader,
R: ReadRef<'data>,
{
#[inline]
fn index(&self) -> SymbolIndex {
self.index
}
fn name_bytes(&self) -> Result<&'data [u8]> {
self.nlist.name(self.file.endian, self.file.symbols.strings)
}
fn name(&self) -> Result<&'data str> {
let name = self.name_bytes()?;
str::from_utf8(name)
.ok()
.read_error("Non UTF-8 Mach-O symbol name")
}
#[inline]
fn address(&self) -> u64 {
self.nlist.n_value(self.file.endian).into()
}
#[inline]
fn size(&self) -> u64 {
0
}
fn kind(&self) -> SymbolKind {
self.section()
.index()
.and_then(|index| self.file.section_internal(index).ok())
.map(|section| match section.kind {
SectionKind::Text => SymbolKind::Text,
SectionKind::Data
| SectionKind::ReadOnlyData
| SectionKind::ReadOnlyString
| SectionKind::UninitializedData
| SectionKind::Common => SymbolKind::Data,
SectionKind::Tls | SectionKind::UninitializedTls | SectionKind::TlsVariables => {
SymbolKind::Tls
}
_ => SymbolKind::Unknown,
})
.unwrap_or(SymbolKind::Unknown)
}
fn section(&self) -> SymbolSection {
match self.nlist.n_type() & macho::N_TYPE {
macho::N_UNDF => SymbolSection::Undefined,
macho::N_ABS => SymbolSection::Absolute,
macho::N_SECT => {
let n_sect = self.nlist.n_sect();
if n_sect != 0 {
SymbolSection::Section(SectionIndex(n_sect as usize))
} else {
SymbolSection::Unknown
}
}
_ => SymbolSection::Unknown,
}
}
#[inline]
fn is_undefined(&self) -> bool {
self.nlist.n_type() & macho::N_TYPE == macho::N_UNDF
}
#[inline]
fn is_definition(&self) -> bool {
self.nlist.is_definition()
}
#[inline]
fn is_common(&self) -> bool {
// Mach-O common symbols are based on section, not symbol
false
}
#[inline]
fn is_weak(&self) -> bool {
self.nlist.n_desc(self.file.endian) & (macho::N_WEAK_REF | macho::N_WEAK_DEF) != 0
}
fn scope(&self) -> SymbolScope {
let n_type = self.nlist.n_type();
if n_type & macho::N_TYPE == macho::N_UNDF {
SymbolScope::Unknown
} else if n_type & macho::N_EXT == 0 {
SymbolScope::Compilation
} else if n_type & macho::N_PEXT != 0 {
SymbolScope::Linkage
} else {
SymbolScope::Dynamic
}
}
#[inline]
fn is_global(&self) -> bool {
self.scope() != SymbolScope::Compilation
}
#[inline]
fn is_local(&self) -> bool {
self.scope() == SymbolScope::Compilation
}
#[inline]
fn flags(&self) -> SymbolFlags<SectionIndex, SymbolIndex> {
let n_desc = self.nlist.n_desc(self.file.endian);
SymbolFlags::MachO { n_desc }
}
}
/// A trait for generic access to [`macho::Nlist32`] and [`macho::Nlist64`].
#[allow(missing_docs)]
pub trait Nlist: Debug + Pod {
type Word: Into<u64>;
type Endian: endian::Endian;
fn n_strx(&self, endian: Self::Endian) -> u32;
fn n_type(&self) -> u8;
fn n_sect(&self) -> u8;
fn n_desc(&self, endian: Self::Endian) -> u16;
fn n_value(&self, endian: Self::Endian) -> Self::Word;
fn name<'data, R: ReadRef<'data>>(
&self,
endian: Self::Endian,
strings: StringTable<'data, R>,
) -> Result<&'data [u8]> {
strings
.get(self.n_strx(endian))
.read_error("Invalid Mach-O symbol name offset")
}
/// Return true if this is a STAB symbol.
///
/// This determines the meaning of the `n_type` field.
fn is_stab(&self) -> bool {
self.n_type() & macho::N_STAB != 0
}
/// Return true if this is an undefined symbol.
fn is_undefined(&self) -> bool {
let n_type = self.n_type();
n_type & macho::N_STAB == 0 && n_type & macho::N_TYPE == macho::N_UNDF
}
/// Return true if the symbol is a definition of a function or data object.
fn is_definition(&self) -> bool {
let n_type = self.n_type();
n_type & macho::N_STAB == 0 && n_type & macho::N_TYPE == macho::N_SECT
}
/// Return the library ordinal.
///
/// This is either a 1-based index into the dylib load commands,
/// or a special ordinal.
#[inline]
fn library_ordinal(&self, endian: Self::Endian) -> u8 {
(self.n_desc(endian) >> 8) as u8
}
}
impl<Endian: endian::Endian> Nlist for macho::Nlist32<Endian> {
type Word = u32;
type Endian = Endian;
fn n_strx(&self, endian: Self::Endian) -> u32 {
self.n_strx.get(endian)
}
fn n_type(&self) -> u8 {
self.n_type
}
fn n_sect(&self) -> u8 {
self.n_sect
}
fn n_desc(&self, endian: Self::Endian) -> u16 {
self.n_desc.get(endian)
}
fn n_value(&self, endian: Self::Endian) -> Self::Word {
self.n_value.get(endian)
}
}
impl<Endian: endian::Endian> Nlist for macho::Nlist64<Endian> {
type Word = u64;
type Endian = Endian;
fn n_strx(&self, endian: Self::Endian) -> u32 {
self.n_strx.get(endian)
}
fn n_type(&self) -> u8 {
self.n_type
}
fn n_sect(&self) -> u8 {
self.n_sect
}
fn n_desc(&self, endian: Self::Endian) -> u16 {
self.n_desc.get(endian)
}
fn n_value(&self, endian: Self::Endian) -> Self::Word {
self.n_value.get(endian)
}
}