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use alloc::fmt;
use alloc::vec::Vec;
use core::fmt::Debug;
use core::slice;
use core::str;
use crate::endian::{self, Endianness};
use crate::pod::Pod;
use crate::read::util::StringTable;
use crate::read::{
self, ObjectSymbol, ObjectSymbolTable, ReadError, ReadRef, SectionIndex, SymbolFlags,
SymbolIndex, SymbolKind, SymbolMap, SymbolMapEntry, SymbolScope, SymbolSection,
};
use crate::{elf, U32};
use super::{FileHeader, SectionHeader, SectionTable};
/// A table of symbol entries in an ELF file.
///
/// Also includes the string table used for the symbol names.
#[derive(Debug, Clone, Copy)]
pub struct SymbolTable<'data, Elf: FileHeader, R = &'data [u8]>
where
R: ReadRef<'data>,
{
section: SectionIndex,
string_section: SectionIndex,
shndx_section: SectionIndex,
symbols: &'data [Elf::Sym],
strings: StringTable<'data, R>,
shndx: &'data [U32<Elf::Endian>],
}
impl<'data, Elf: FileHeader, R: ReadRef<'data>> Default for SymbolTable<'data, Elf, R> {
fn default() -> Self {
SymbolTable {
section: SectionIndex(0),
string_section: SectionIndex(0),
shndx_section: SectionIndex(0),
symbols: &[],
strings: Default::default(),
shndx: &[],
}
}
}
impl<'data, Elf: FileHeader, R: ReadRef<'data>> SymbolTable<'data, Elf, R> {
/// Parse the given symbol table section.
pub fn parse(
endian: Elf::Endian,
data: R,
sections: &SectionTable<'data, Elf, R>,
section_index: SectionIndex,
section: &Elf::SectionHeader,
) -> read::Result<SymbolTable<'data, Elf, R>> {
debug_assert!(
section.sh_type(endian) == elf::SHT_DYNSYM
|| section.sh_type(endian) == elf::SHT_SYMTAB
);
let symbols = section
.data_as_array(endian, data)
.read_error("Invalid ELF symbol table data")?;
let link = SectionIndex(section.sh_link(endian) as usize);
let strings = sections.strings(endian, data, link)?;
let mut shndx_section = SectionIndex(0);
let mut shndx = &[][..];
for (i, s) in sections.iter().enumerate() {
if s.sh_type(endian) == elf::SHT_SYMTAB_SHNDX
&& s.sh_link(endian) as usize == section_index.0
{
shndx_section = SectionIndex(i);
shndx = s
.data_as_array(endian, data)
.read_error("Invalid ELF symtab_shndx data")?;
}
}
Ok(SymbolTable {
section: section_index,
string_section: link,
symbols,
strings,
shndx,
shndx_section,
})
}
/// Return the section index of this symbol table.
#[inline]
pub fn section(&self) -> SectionIndex {
self.section
}
/// Return the section index of the shndx table.
#[inline]
pub fn shndx_section(&self) -> SectionIndex {
self.shndx_section
}
/// Return the section index of the linked string table.
#[inline]
pub fn string_section(&self) -> SectionIndex {
self.string_section
}
/// Return the string table used for the symbol names.
#[inline]
pub fn strings(&self) -> StringTable<'data, R> {
self.strings
}
/// Return the symbol table.
#[inline]
pub fn symbols(&self) -> &'data [Elf::Sym] {
self.symbols
}
/// Iterate over the symbols.
#[inline]
pub fn iter(&self) -> slice::Iter<'data, Elf::Sym> {
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: usize) -> read::Result<&'data Elf::Sym> {
self.symbols
.get(index)
.read_error("Invalid ELF symbol index")
}
/// Return the extended section index for the given symbol if present.
#[inline]
pub fn shndx(&self, endian: Elf::Endian, index: usize) -> Option<u32> {
self.shndx.get(index).map(|x| x.get(endian))
}
/// Return the section index for the given symbol.
///
/// This uses the extended section index if present.
pub fn symbol_section(
&self,
endian: Elf::Endian,
symbol: &'data Elf::Sym,
index: usize,
) -> read::Result<Option<SectionIndex>> {
match symbol.st_shndx(endian) {
elf::SHN_UNDEF => Ok(None),
elf::SHN_XINDEX => self
.shndx(endian, index)
.read_error("Missing ELF symbol extended index")
.map(|index| Some(SectionIndex(index as usize))),
shndx if shndx < elf::SHN_LORESERVE => Ok(Some(SectionIndex(shndx.into()))),
_ => Ok(None),
}
}
/// Return the symbol name for the given symbol.
pub fn symbol_name(
&self,
endian: Elf::Endian,
symbol: &'data Elf::Sym,
) -> read::Result<&'data [u8]> {
symbol.name(endian, self.strings)
}
/// Construct a map from addresses to a user-defined map entry.
pub fn map<Entry: SymbolMapEntry, F: Fn(&'data Elf::Sym) -> Option<Entry>>(
&self,
endian: Elf::Endian,
f: F,
) -> SymbolMap<Entry> {
let mut symbols = Vec::with_capacity(self.symbols.len());
for symbol in self.symbols {
if !symbol.is_definition(endian) {
continue;
}
if let Some(entry) = f(symbol) {
symbols.push(entry);
}
}
SymbolMap::new(symbols)
}
}
/// A symbol table of an `ElfFile32`.
pub type ElfSymbolTable32<'data, 'file, Endian = Endianness, R = &'data [u8]> =
ElfSymbolTable<'data, 'file, elf::FileHeader32<Endian>, R>;
/// A symbol table of an `ElfFile32`.
pub type ElfSymbolTable64<'data, 'file, Endian = Endianness, R = &'data [u8]> =
ElfSymbolTable<'data, 'file, elf::FileHeader64<Endian>, R>;
/// A symbol table of an `ElfFile`.
#[derive(Debug, Clone, Copy)]
pub struct ElfSymbolTable<'data, 'file, Elf, R = &'data [u8]>
where
Elf: FileHeader,
R: ReadRef<'data>,
{
pub(super) endian: Elf::Endian,
pub(super) symbols: &'file SymbolTable<'data, Elf, R>,
}
impl<'data, 'file, Elf: FileHeader, R: ReadRef<'data>> read::private::Sealed
for ElfSymbolTable<'data, 'file, Elf, R>
{
}
impl<'data, 'file, Elf: FileHeader, R: ReadRef<'data>> ObjectSymbolTable<'data>
for ElfSymbolTable<'data, 'file, Elf, R>
{
type Symbol = ElfSymbol<'data, 'file, Elf, R>;
type SymbolIterator = ElfSymbolIterator<'data, 'file, Elf, R>;
fn symbols(&self) -> Self::SymbolIterator {
ElfSymbolIterator {
endian: self.endian,
symbols: self.symbols,
index: 0,
}
}
fn symbol_by_index(&self, index: SymbolIndex) -> read::Result<Self::Symbol> {
let symbol = self.symbols.symbol(index.0)?;
Ok(ElfSymbol {
endian: self.endian,
symbols: self.symbols,
index,
symbol,
})
}
}
/// An iterator over the symbols of an `ElfFile32`.
pub type ElfSymbolIterator32<'data, 'file, Endian = Endianness, R = &'data [u8]> =
ElfSymbolIterator<'data, 'file, elf::FileHeader32<Endian>, R>;
/// An iterator over the symbols of an `ElfFile64`.
pub type ElfSymbolIterator64<'data, 'file, Endian = Endianness, R = &'data [u8]> =
ElfSymbolIterator<'data, 'file, elf::FileHeader64<Endian>, R>;
/// An iterator over the symbols of an `ElfFile`.
pub struct ElfSymbolIterator<'data, 'file, Elf, R = &'data [u8]>
where
Elf: FileHeader,
R: ReadRef<'data>,
{
pub(super) endian: Elf::Endian,
pub(super) symbols: &'file SymbolTable<'data, Elf, R>,
pub(super) index: usize,
}
impl<'data, 'file, Elf: FileHeader, R: ReadRef<'data>> fmt::Debug
for ElfSymbolIterator<'data, 'file, Elf, R>
{
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_struct("ElfSymbolIterator").finish()
}
}
impl<'data, 'file, Elf: FileHeader, R: ReadRef<'data>> Iterator
for ElfSymbolIterator<'data, 'file, Elf, R>
{
type Item = ElfSymbol<'data, 'file, Elf, R>;
fn next(&mut self) -> Option<Self::Item> {
let index = self.index;
let symbol = self.symbols.symbols.get(index)?;
self.index += 1;
Some(ElfSymbol {
endian: self.endian,
symbols: self.symbols,
index: SymbolIndex(index),
symbol,
})
}
}
/// A symbol of an `ElfFile32`.
pub type ElfSymbol32<'data, 'file, Endian = Endianness, R = &'data [u8]> =
ElfSymbol<'data, 'file, elf::FileHeader32<Endian>, R>;
/// A symbol of an `ElfFile64`.
pub type ElfSymbol64<'data, 'file, Endian = Endianness, R = &'data [u8]> =
ElfSymbol<'data, 'file, elf::FileHeader64<Endian>, R>;
/// A symbol of an `ElfFile`.
#[derive(Debug, Clone, Copy)]
pub struct ElfSymbol<'data, 'file, Elf, R = &'data [u8]>
where
Elf: FileHeader,
R: ReadRef<'data>,
{
pub(super) endian: Elf::Endian,
pub(super) symbols: &'file SymbolTable<'data, Elf, R>,
pub(super) index: SymbolIndex,
pub(super) symbol: &'data Elf::Sym,
}
impl<'data, 'file, Elf: FileHeader, R: ReadRef<'data>> ElfSymbol<'data, 'file, Elf, R> {
/// Return a reference to the raw symbol structure.
#[inline]
pub fn raw_symbol(&self) -> &'data Elf::Sym {
self.symbol
}
}
impl<'data, 'file, Elf: FileHeader, R: ReadRef<'data>> read::private::Sealed
for ElfSymbol<'data, 'file, Elf, R>
{
}
impl<'data, 'file, Elf: FileHeader, R: ReadRef<'data>> ObjectSymbol<'data>
for ElfSymbol<'data, 'file, Elf, R>
{
#[inline]
fn index(&self) -> SymbolIndex {
self.index
}
fn name_bytes(&self) -> read::Result<&'data [u8]> {
self.symbol.name(self.endian, self.symbols.strings())
}
fn name(&self) -> read::Result<&'data str> {
let name = self.name_bytes()?;
str::from_utf8(name)
.ok()
.read_error("Non UTF-8 ELF symbol name")
}
#[inline]
fn address(&self) -> u64 {
self.symbol.st_value(self.endian).into()
}
#[inline]
fn size(&self) -> u64 {
self.symbol.st_size(self.endian).into()
}
fn kind(&self) -> SymbolKind {
match self.symbol.st_type() {
elf::STT_NOTYPE if self.index.0 == 0 => SymbolKind::Null,
elf::STT_NOTYPE => SymbolKind::Label,
elf::STT_OBJECT | elf::STT_COMMON => SymbolKind::Data,
elf::STT_FUNC | elf::STT_GNU_IFUNC => SymbolKind::Text,
elf::STT_SECTION => SymbolKind::Section,
elf::STT_FILE => SymbolKind::File,
elf::STT_TLS => SymbolKind::Tls,
_ => SymbolKind::Unknown,
}
}
fn section(&self) -> SymbolSection {
match self.symbol.st_shndx(self.endian) {
elf::SHN_UNDEF => SymbolSection::Undefined,
elf::SHN_ABS => {
if self.symbol.st_type() == elf::STT_FILE {
SymbolSection::None
} else {
SymbolSection::Absolute
}
}
elf::SHN_COMMON => SymbolSection::Common,
elf::SHN_XINDEX => match self.symbols.shndx(self.endian, self.index.0) {
Some(index) => SymbolSection::Section(SectionIndex(index as usize)),
None => SymbolSection::Unknown,
},
index if index < elf::SHN_LORESERVE => {
SymbolSection::Section(SectionIndex(index as usize))
}
_ => SymbolSection::Unknown,
}
}
#[inline]
fn is_undefined(&self) -> bool {
self.symbol.st_shndx(self.endian) == elf::SHN_UNDEF
}
#[inline]
fn is_definition(&self) -> bool {
self.symbol.is_definition(self.endian)
}
#[inline]
fn is_common(&self) -> bool {
self.symbol.st_shndx(self.endian) == elf::SHN_COMMON
}
#[inline]
fn is_weak(&self) -> bool {
self.symbol.st_bind() == elf::STB_WEAK
}
fn scope(&self) -> SymbolScope {
if self.symbol.st_shndx(self.endian) == elf::SHN_UNDEF {
SymbolScope::Unknown
} else {
match self.symbol.st_bind() {
elf::STB_LOCAL => SymbolScope::Compilation,
elf::STB_GLOBAL | elf::STB_WEAK => {
if self.symbol.st_visibility() == elf::STV_HIDDEN {
SymbolScope::Linkage
} else {
SymbolScope::Dynamic
}
}
_ => SymbolScope::Unknown,
}
}
}
#[inline]
fn is_global(&self) -> bool {
self.symbol.st_bind() != elf::STB_LOCAL
}
#[inline]
fn is_local(&self) -> bool {
self.symbol.st_bind() == elf::STB_LOCAL
}
#[inline]
fn flags(&self) -> SymbolFlags<SectionIndex, SymbolIndex> {
SymbolFlags::Elf {
st_info: self.symbol.st_info(),
st_other: self.symbol.st_other(),
}
}
}
/// A trait for generic access to `Sym32` and `Sym64`.
#[allow(missing_docs)]
pub trait Sym: Debug + Pod {
type Word: Into<u64>;
type Endian: endian::Endian;
fn st_name(&self, endian: Self::Endian) -> u32;
fn st_info(&self) -> u8;
fn st_bind(&self) -> u8;
fn st_type(&self) -> u8;
fn st_other(&self) -> u8;
fn st_visibility(&self) -> u8;
fn st_shndx(&self, endian: Self::Endian) -> u16;
fn st_value(&self, endian: Self::Endian) -> Self::Word;
fn st_size(&self, endian: Self::Endian) -> Self::Word;
/// Parse the symbol name from the string table.
fn name<'data, R: ReadRef<'data>>(
&self,
endian: Self::Endian,
strings: StringTable<'data, R>,
) -> read::Result<&'data [u8]> {
strings
.get(self.st_name(endian))
.read_error("Invalid ELF symbol name offset")
}
/// Return true if the symbol is undefined.
#[inline]
fn is_undefined(&self, endian: Self::Endian) -> bool {
self.st_shndx(endian) == elf::SHN_UNDEF
}
/// Return true if the symbol is a definition of a function or data object.
fn is_definition(&self, endian: Self::Endian) -> bool {
let st_type = self.st_type();
(st_type == elf::STT_NOTYPE || st_type == elf::STT_FUNC || st_type == elf::STT_OBJECT)
&& self.st_shndx(endian) != elf::SHN_UNDEF
}
}
impl<Endian: endian::Endian> Sym for elf::Sym32<Endian> {
type Word = u32;
type Endian = Endian;
#[inline]
fn st_name(&self, endian: Self::Endian) -> u32 {
self.st_name.get(endian)
}
#[inline]
fn st_info(&self) -> u8 {
self.st_info
}
#[inline]
fn st_bind(&self) -> u8 {
self.st_bind()
}
#[inline]
fn st_type(&self) -> u8 {
self.st_type()
}
#[inline]
fn st_other(&self) -> u8 {
self.st_other
}
#[inline]
fn st_visibility(&self) -> u8 {
self.st_visibility()
}
#[inline]
fn st_shndx(&self, endian: Self::Endian) -> u16 {
self.st_shndx.get(endian)
}
#[inline]
fn st_value(&self, endian: Self::Endian) -> Self::Word {
self.st_value.get(endian)
}
#[inline]
fn st_size(&self, endian: Self::Endian) -> Self::Word {
self.st_size.get(endian)
}
}
impl<Endian: endian::Endian> Sym for elf::Sym64<Endian> {
type Word = u64;
type Endian = Endian;
#[inline]
fn st_name(&self, endian: Self::Endian) -> u32 {
self.st_name.get(endian)
}
#[inline]
fn st_info(&self) -> u8 {
self.st_info
}
#[inline]
fn st_bind(&self) -> u8 {
self.st_bind()
}
#[inline]
fn st_type(&self) -> u8 {
self.st_type()
}
#[inline]
fn st_other(&self) -> u8 {
self.st_other
}
#[inline]
fn st_visibility(&self) -> u8 {
self.st_visibility()
}
#[inline]
fn st_shndx(&self, endian: Self::Endian) -> u16 {
self.st_shndx.get(endian)
}
#[inline]
fn st_value(&self, endian: Self::Endian) -> Self::Word {
self.st_value.get(endian)
}
#[inline]
fn st_size(&self, endian: Self::Endian) -> Self::Word {
self.st_size.get(endian)
}
}