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#[macro_use] extern crate bitflags; extern crate cesu8; #[macro_use] pub mod error; pub mod attributes; pub mod constant_pool; use std::borrow::Cow; use std::ops::Deref; use std::rc::Rc; pub use crate::error::ParseError; use crate::attributes::{AttributeData, AttributeInfo, read_attributes}; use crate::constant_pool::{ConstantPoolEntry, ConstantPoolIter, read_constant_pool, read_cp_utf8, read_cp_classinfo, read_cp_classinfo_opt}; pub(crate) fn read_u1(bytes: &[u8], ix: &mut usize) -> Result<u8, ParseError> { if bytes.len() < *ix + 1 { fail!("Unexpected end of stream reading u1 at index {}", *ix); } let result = bytes[*ix]; *ix += 1; Ok(result) } pub(crate) fn read_u2(bytes: &[u8], ix: &mut usize) -> Result<u16, ParseError> { if bytes.len() < *ix + 2 { fail!("Unexpected end of stream reading u2 at index {}", *ix); } let result = ((bytes[*ix + 0] as u16) << 8) | ((bytes[*ix + 1] as u16)); *ix += 2; Ok(result) } pub(crate) fn read_u4(bytes: &[u8], ix: &mut usize) -> Result<u32, ParseError> { if bytes.len() < *ix + 4 { fail!("Unexpected end of stream reading u4 at index {}", *ix); } let result = ((bytes[*ix + 0] as u32) << 24) | ((bytes[*ix + 1] as u32) << 16) | ((bytes[*ix + 2] as u32) << 8) | ((bytes[*ix + 3] as u32)); *ix += 4; Ok(result) } pub(crate) fn read_u8(bytes: &[u8], ix: &mut usize) -> Result<u64, ParseError> { if bytes.len() < *ix + 8 { fail!("Unexpected end of stream reading u8 at index {}", *ix); } let result = ((bytes[*ix + 0] as u64) << 56) | ((bytes[*ix + 1] as u64) << 48) | ((bytes[*ix + 2] as u64) << 40) | ((bytes[*ix + 3] as u64) << 32) | ((bytes[*ix + 4] as u64) << 24) | ((bytes[*ix + 5] as u64) << 16) | ((bytes[*ix + 6] as u64) << 8) | ((bytes[*ix + 7] as u64)); *ix += 8; Ok(result) } fn read_interfaces<'a>(bytes: &'a [u8], ix: &mut usize, pool: &[Rc<ConstantPoolEntry<'a>>]) -> Result<Vec<Cow<'a, str>>, ParseError> { let count = read_u2(bytes, ix)?; let mut interfaces = Vec::with_capacity(count.into()); for i in 0..count { interfaces.push(read_cp_classinfo(bytes, ix, pool).map_err(|e| err!(e, "interface {}", i))?); } Ok(interfaces) } bitflags! { pub struct AccessFlags: u16 { const PUBLIC = 0x0001; const PRIVATE = 0x0002; const PROTECTED = 0x0004; const STATIC = 0x0008; const FINAL = 0x0010; const SUPER = 0x0020; const SYNCHRONIZED = 0x0020; const OPEN = 0x0020; const TRANSITIVE = 0x0020; const VOLATILE = 0x0040; const BRIDGE = 0x0040; const STATIC_PHASE = 0x0040; const TRANSIENT = 0x0080; const VARARGS = 0x0080; const NATIVE = 0x0100; const INTERFACE = 0x0200; const ABSTRACT = 0x0400; const STRICT = 0x0800; const SYNTHETIC = 0x1000; const ANNOTATION = 0x2000; const ENUM = 0x4000; const MANDATED = 0x8000; const MODULE = 0x8000; } } bitflags! { pub struct FieldAccessFlags: u16 { const PUBLIC = AccessFlags::PUBLIC.bits(); const PRIVATE = AccessFlags::PRIVATE.bits(); const PROTECTED = AccessFlags::PROTECTED.bits(); const STATIC = AccessFlags::STATIC.bits(); const FINAL = AccessFlags::FINAL.bits(); const VOLATILE = AccessFlags::VOLATILE.bits(); const TRANSIENT = AccessFlags::TRANSIENT.bits(); const SYNTHETIC = AccessFlags::SYNTHETIC.bits(); const ENUM = AccessFlags::ENUM.bits(); } } #[derive(Debug)] pub struct FieldInfo<'a> { pub access_flags: FieldAccessFlags, pub name: Cow<'a, str>, pub descriptor: Cow<'a, str>, pub attributes: Vec<AttributeInfo<'a>>, } fn read_fields<'a>(bytes: &'a [u8], ix: &mut usize, pool: &[Rc<ConstantPoolEntry<'a>>]) -> Result<Vec<FieldInfo<'a>>, ParseError> { let count = read_u2(bytes, ix)?; let mut fields = Vec::with_capacity(count.into()); for i in 0..count { let access_flags = FieldAccessFlags::from_bits_truncate(read_u2(bytes, ix)?); let name = read_cp_utf8(bytes, ix, pool).map_err(|e| err!(e, "name of class field {}", i))?; let descriptor = read_cp_utf8(bytes, ix, pool).map_err(|e| err!(e, "descriptor of class field {}", i))?; let attributes = read_attributes(bytes, ix, pool).map_err(|e| err!(e, "class field {}", i))?; fields.push(FieldInfo { access_flags, name, descriptor, attributes, }); } Ok(fields) } bitflags! { pub struct MethodAccessFlags: u16 { const PUBLIC = AccessFlags::PUBLIC.bits(); const PRIVATE = AccessFlags::PRIVATE.bits(); const PROTECTED = AccessFlags::PROTECTED.bits(); const STATIC = AccessFlags::STATIC.bits(); const FINAL = AccessFlags::FINAL.bits(); const SYNCHRONIZED = AccessFlags::SYNCHRONIZED.bits(); const BRIDGE = AccessFlags::BRIDGE.bits(); const VARARGS = AccessFlags::VARARGS.bits(); const NATIVE = AccessFlags::NATIVE.bits(); const ABSTRACT = AccessFlags::ABSTRACT.bits(); const STRICT = AccessFlags::STRICT.bits(); const SYNTHETIC = AccessFlags::SYNTHETIC.bits(); } } #[derive(Debug)] pub struct MethodInfo<'a> { pub access_flags: MethodAccessFlags, pub name: Cow<'a, str>, pub descriptor: Cow<'a, str>, pub attributes: Vec<AttributeInfo<'a>>, } fn read_methods<'a>(bytes: &'a [u8], ix: &mut usize, pool: &[Rc<ConstantPoolEntry<'a>>]) -> Result<Vec<MethodInfo<'a>>, ParseError> { let count = read_u2(bytes, ix)?; let mut methods = Vec::with_capacity(count.into()); for i in 0..count { let access_flags = MethodAccessFlags::from_bits_truncate(read_u2(bytes, ix)?); let name = read_cp_utf8(bytes, ix, pool).map_err(|e| err!(e, "name of class method {}", i))?; let descriptor = read_cp_utf8(bytes, ix, pool).map_err(|e| err!(e, "descriptor of class method {}", i))?; let attributes = read_attributes(bytes, ix, pool).map_err(|e| err!(e, "class method {}", i))?; methods.push(MethodInfo { access_flags, name, descriptor, attributes, }); } Ok(methods) } bitflags! { pub struct ClassAccessFlags: u16 { const PUBLIC = AccessFlags::PUBLIC.bits(); const FINAL = AccessFlags::FINAL.bits(); const SUPER = AccessFlags::SUPER.bits(); const INTERFACE = AccessFlags::INTERFACE.bits(); const ABSTRACT = AccessFlags::ABSTRACT.bits(); const SYNTHETIC = AccessFlags::SYNTHETIC.bits(); const ANNOTATION = AccessFlags::ANNOTATION.bits(); const ENUM = AccessFlags::ENUM.bits(); const MODULE = AccessFlags::MODULE.bits(); } } fn validate_bootstrap_methods<'a>(pool: &[Rc<ConstantPoolEntry<'a>>], attributes: &[AttributeInfo<'a>]) -> Result<(), ParseError> { for cp_entry in pool { match cp_entry.deref() { ConstantPoolEntry::Dynamic(x, _) | ConstantPoolEntry::InvokeDynamic(x, _) => { let mut found = 0; for attr in attributes { match &attr.data { AttributeData::BootstrapMethods(methods) => { found += 1; if usize::from(*x) >= methods.len() { fail!("Constant pool item contained invalid index into BootstrapMethods class attribute"); } } _ => continue, } } if found != 1 { fail!("Found unexpected number of BootstrapMethods attributes in class; found {}, expected 1", found); } } _ => continue, }; } Ok(()) } #[derive(Debug)] pub struct ClassFile<'a> { pub major_version: u16, pub minor_version: u16, constant_pool: Vec<Rc<ConstantPoolEntry<'a>>>, pub access_flags: ClassAccessFlags, pub this_class: Cow<'a, str>, pub super_class: Option<Cow<'a, str>>, pub interfaces: Vec<Cow<'a, str>>, pub fields: Vec<FieldInfo<'a>>, pub methods: Vec<MethodInfo<'a>>, pub attributes: Vec<AttributeInfo<'a>>, } impl<'a> ClassFile<'a> { pub fn constantpool_iter(&'a self) -> ConstantPoolIter<'a> { ConstantPoolIter::new(&self.constant_pool) } } pub fn parse_class<'a>(raw_bytes: &'a [u8]) -> Result<ClassFile<'a>, ParseError> { let mut ix = 0; if read_u4(raw_bytes, &mut ix)? != 0xCAFEBABE { fail!("Unexpected magic header"); } let minor_version = read_u2(raw_bytes, &mut ix)?; let major_version = read_u2(raw_bytes, &mut ix)?; let constant_pool = read_constant_pool(raw_bytes, &mut ix, major_version)?; let access_flags = ClassAccessFlags::from_bits_truncate(read_u2(raw_bytes, &mut ix)?); let is_module = access_flags.contains(ClassAccessFlags::MODULE); if is_module { if major_version < 53 { fail!("Found invalid MODULE class access flag on class file of major version {}", major_version); } if access_flags != ClassAccessFlags::MODULE { fail!("Found invalid class access flags {:?}; no other flags should be set with MODULE", access_flags); } } let this_class = read_cp_classinfo(raw_bytes, &mut ix, &constant_pool).map_err(|e| err!(e, "this_class"))?; let super_class = read_cp_classinfo_opt(raw_bytes, &mut ix, &constant_pool).map_err(|e| err!(e, "super_class"))?; let interfaces = read_interfaces(raw_bytes, &mut ix, &constant_pool)?; let fields = read_fields(raw_bytes, &mut ix, &constant_pool)?; let methods = read_methods(raw_bytes, &mut ix, &constant_pool)?; let attributes = read_attributes(raw_bytes, &mut ix, &constant_pool).map_err(|e| err!(e, "class"))?; if is_module { if super_class.is_some() { fail!("Found non-empty super_class {}; expected none for module", super_class.unwrap()); } if interfaces.len() != 0 { fail!("Found {} interfaces; expected 0 for module", interfaces.len()); } if fields.len() != 0 { fail!("Found {} fields; expected 0 for module", fields.len()); } if methods.len() != 0 { fail!("Found {} methods; expected 0 for module", methods.len()); } } validate_bootstrap_methods(&constant_pool, &attributes)?; let class_file = ClassFile { major_version, minor_version, constant_pool, access_flags, this_class, super_class, interfaces, fields, methods, attributes, }; Ok(class_file) }