diff options
Diffstat (limited to 'third_party/rust/object/src/read/coff/import.rs')
-rw-r--r-- | third_party/rust/object/src/read/coff/import.rs | 209 |
1 files changed, 209 insertions, 0 deletions
diff --git a/third_party/rust/object/src/read/coff/import.rs b/third_party/rust/object/src/read/coff/import.rs new file mode 100644 index 0000000000..d635e7592a --- /dev/null +++ b/third_party/rust/object/src/read/coff/import.rs @@ -0,0 +1,209 @@ +//! Support for reading short import files. +//! +//! These are used by some Windows linkers as a more compact way to describe +//! dynamically imported symbols. + +use crate::read::{Architecture, Error, ReadError, ReadRef, Result}; +use crate::{pe, ByteString, Bytes, LittleEndian as LE}; + +/// A Windows short form description of a symbol to import. +/// +/// Used in Windows import libraries to provide a mapping from +/// a symbol name to a DLL export. This is not an object file. +#[derive(Debug, Clone)] +pub struct ImportFile<'data> { + header: &'data pe::ImportObjectHeader, + kind: ImportType, + dll: ByteString<'data>, + symbol: ByteString<'data>, + import: Option<ByteString<'data>>, +} + +impl<'data> ImportFile<'data> { + /// Parse it. + pub fn parse<R: ReadRef<'data>>(data: R) -> Result<Self> { + let mut offset = 0; + let header = pe::ImportObjectHeader::parse(data, &mut offset)?; + let data = header.parse_data(data, &mut offset)?; + + // Unmangles a name by removing a `?`, `@` or `_` prefix. + fn strip_prefix(s: &[u8]) -> &[u8] { + match s.split_first() { + Some((b, rest)) if [b'?', b'@', b'_'].contains(b) => rest, + _ => s, + } + } + Ok(Self { + header, + dll: data.dll, + symbol: data.symbol, + kind: match header.import_type() { + pe::IMPORT_OBJECT_CODE => ImportType::Code, + pe::IMPORT_OBJECT_DATA => ImportType::Data, + pe::IMPORT_OBJECT_CONST => ImportType::Const, + _ => return Err(Error("Invalid COFF import library import type")), + }, + import: match header.name_type() { + pe::IMPORT_OBJECT_ORDINAL => None, + pe::IMPORT_OBJECT_NAME => Some(data.symbol()), + pe::IMPORT_OBJECT_NAME_NO_PREFIX => Some(strip_prefix(data.symbol())), + pe::IMPORT_OBJECT_NAME_UNDECORATE => Some( + strip_prefix(data.symbol()) + .split(|&b| b == b'@') + .next() + .unwrap(), + ), + pe::IMPORT_OBJECT_NAME_EXPORTAS => data.export(), + _ => return Err(Error("Unknown COFF import library name type")), + } + .map(ByteString), + }) + } + + /// Get the machine type. + pub fn architecture(&self) -> Architecture { + match self.header.machine.get(LE) { + pe::IMAGE_FILE_MACHINE_ARMNT => Architecture::Arm, + pe::IMAGE_FILE_MACHINE_ARM64 => Architecture::Aarch64, + pe::IMAGE_FILE_MACHINE_I386 => Architecture::I386, + pe::IMAGE_FILE_MACHINE_AMD64 => Architecture::X86_64, + _ => Architecture::Unknown, + } + } + + /// The public symbol name. + pub fn symbol(&self) -> &'data [u8] { + self.symbol.0 + } + + /// The name of the DLL to import the symbol from. + pub fn dll(&self) -> &'data [u8] { + self.dll.0 + } + + /// The name exported from the DLL. + pub fn import(&self) -> ImportName<'data> { + match self.import { + Some(name) => ImportName::Name(name.0), + None => ImportName::Ordinal(self.header.ordinal_or_hint.get(LE)), + } + } + + /// The type of import. Usually either a function or data. + pub fn import_type(&self) -> ImportType { + self.kind + } +} + +/// The name or ordinal to import from a DLL. +#[derive(Debug, Clone, Copy, PartialEq, Eq)] +pub enum ImportName<'data> { + /// Import by ordinal. Ordinarily this is a 1-based index. + Ordinal(u16), + /// Import by name. + Name(&'data [u8]), +} + +/// The kind of import symbol. +#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)] +pub enum ImportType { + /// An executable code symbol. + Code, + /// A data symbol. + Data, + /// A constant value. + Const, +} + +impl pe::ImportObjectHeader { + /// Read the short import header. + /// + /// Also checks that the signature and version are valid. + /// Directly following this header will be the string data. + pub fn parse<'data, R: ReadRef<'data>>(data: R, offset: &mut u64) -> Result<&'data Self> { + let header = data + .read::<pe::ImportObjectHeader>(offset) + .read_error("Invalid COFF import library header size")?; + if header.sig1.get(LE) != 0 || header.sig2.get(LE) != pe::IMPORT_OBJECT_HDR_SIG2 { + Err(Error("Invalid COFF import library header")) + } else if header.version.get(LE) != 0 { + Err(Error("Unknown COFF import library header version")) + } else { + Ok(header) + } + } + + /// Parse the data following the header. + pub fn parse_data<'data, R: ReadRef<'data>>( + &self, + data: R, + offset: &mut u64, + ) -> Result<ImportObjectData<'data>> { + let mut data = Bytes( + data.read_bytes(offset, u64::from(self.size_of_data.get(LE))) + .read_error("Invalid COFF import library data size")?, + ); + let symbol = data + .read_string() + .map(ByteString) + .read_error("Could not read COFF import library symbol name")?; + let dll = data + .read_string() + .map(ByteString) + .read_error("Could not read COFF import library DLL name")?; + let export = if self.name_type() == pe::IMPORT_OBJECT_NAME_EXPORTAS { + data.read_string() + .map(ByteString) + .map(Some) + .read_error("Could not read COFF import library export name")? + } else { + None + }; + Ok(ImportObjectData { + symbol, + dll, + export, + }) + } + + /// The type of import. + /// + /// This is one of the `IMPORT_OBJECT_*` constants. + pub fn import_type(&self) -> u16 { + self.name_type.get(LE) & pe::IMPORT_OBJECT_TYPE_MASK + } + + /// The type of import name. + /// + /// This is one of the `IMPORT_OBJECT_*` constants. + pub fn name_type(&self) -> u16 { + (self.name_type.get(LE) >> pe::IMPORT_OBJECT_NAME_SHIFT) & pe::IMPORT_OBJECT_NAME_MASK + } +} + +/// The data following `ImportObjectHeader`. +#[derive(Debug, Clone)] +pub struct ImportObjectData<'data> { + symbol: ByteString<'data>, + dll: ByteString<'data>, + export: Option<ByteString<'data>>, +} + +impl<'data> ImportObjectData<'data> { + /// The public symbol name. + pub fn symbol(&self) -> &'data [u8] { + self.symbol.0 + } + + /// The name of the DLL to import the symbol from. + pub fn dll(&self) -> &'data [u8] { + self.dll.0 + } + + /// The name exported from the DLL. + /// + /// This is only set if the name is not derived from the symbol name. + pub fn export(&self) -> Option<&'data [u8]> { + self.export.map(|export| export.0) + } +} |