diff options
Diffstat (limited to 'third_party/rust/object/src/read/elf/symbol.rs')
-rw-r--r-- | third_party/rust/object/src/read/elf/symbol.rs | 585 |
1 files changed, 585 insertions, 0 deletions
diff --git a/third_party/rust/object/src/read/elf/symbol.rs b/third_party/rust/object/src/read/elf/symbol.rs new file mode 100644 index 0000000000..ee5aa37f19 --- /dev/null +++ b/third_party/rust/object/src/read/elf/symbol.rs @@ -0,0 +1,585 @@ +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) + } +} |