diff options
Diffstat (limited to 'third_party/rust/object/src/read/macho/symbol.rs')
| -rw-r--r-- | third_party/rust/object/src/read/macho/symbol.rs | 488 |
1 files changed, 488 insertions, 0 deletions
diff --git a/third_party/rust/object/src/read/macho/symbol.rs b/third_party/rust/object/src/read/macho/symbol.rs new file mode 100644 index 0000000000..e102c5d0b6 --- /dev/null +++ b/third_party/rust/object/src/read/macho/symbol.rs @@ -0,0 +1,488 @@ +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, 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. +#[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: usize) -> Result<&'data Mach::Nlist> { + self.symbols + .get(index) + .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()); + objects.push(name); + } + } + } + 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, + } + } +} + +/// An iterator over the symbols of a `MachOFile32`. +pub type MachOSymbolTable32<'data, 'file, Endian = Endianness, R = &'data [u8]> = + MachOSymbolTable<'data, 'file, macho::MachHeader32<Endian>, R>; +/// An iterator over the symbols of a `MachOFile64`. +pub type MachOSymbolTable64<'data, 'file, Endian = Endianness, R = &'data [u8]> = + MachOSymbolTable<'data, 'file, macho::MachHeader64<Endian>, R>; + +/// A symbol table of 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 { + file: self.file, + index: 0, + } + } + + fn symbol_by_index(&self, index: SymbolIndex) -> Result<Self::Symbol> { + let nlist = self.file.symbols.symbol(index.0)?; + MachOSymbol::new(self.file, index, nlist).read_error("Unsupported Mach-O symbol index") + } +} + +/// An iterator over the symbols of a `MachOFile32`. +pub type MachOSymbolIterator32<'data, 'file, Endian = Endianness, R = &'data [u8]> = + MachOSymbolIterator<'data, 'file, macho::MachHeader32<Endian>, R>; +/// An iterator over the symbols of a `MachOFile64`. +pub type MachOSymbolIterator64<'data, 'file, Endian = Endianness, R = &'data [u8]> = + MachOSymbolIterator<'data, 'file, macho::MachHeader64<Endian>, R>; + +/// An iterator over the symbols of a `MachOFile`. +pub struct MachOSymbolIterator<'data, 'file, Mach, R = &'data [u8]> +where + Mach: MachHeader, + R: ReadRef<'data>, +{ + pub(super) file: &'file MachOFile<'data, Mach, R>, + pub(super) index: usize, +} + +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)?; + self.index += 1; + if let Some(symbol) = MachOSymbol::new(self.file, SymbolIndex(index), nlist) { + return Some(symbol); + } + } + } +} + +/// A symbol of a `MachOFile32`. +pub type MachOSymbol32<'data, 'file, Endian = Endianness, R = &'data [u8]> = + MachOSymbol<'data, 'file, macho::MachHeader32<Endian>, R>; +/// A symbol of a `MachOFile64`. +pub type MachOSymbol64<'data, 'file, Endian = Endianness, R = &'data [u8]> = + MachOSymbol<'data, 'file, macho::MachHeader64<Endian>, R>; + +/// A symbol of a `MachOFile`. +#[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 }) + } +} + +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> { + let n_desc = self.nlist.n_desc(self.file.endian); + SymbolFlags::MachO { n_desc } + } +} + +/// A trait for generic access to `Nlist32` and `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_UNDF + } + + /// 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) + } +} |