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Use separate base address structs for .eh_frame and .eh_frame_hdr #351

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Jan 7, 2019
Merged

Use separate base address structs for .eh_frame and .eh_frame_hdr #351

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446c0b9
Use separate base address structs for .eh_frame and .eh_frame_hdr
philipc Jan 3, 2019
4aafcd8
read/cfi: change size_of tests to be an upper bound
philipc Jan 3, 2019
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25 changes: 20 additions & 5 deletions benches/bench.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -519,7 +519,10 @@ mod cfi {
let eh_frame = read_section("eh_frame");
let eh_frame = EhFrame::new(&eh_frame, LittleEndian);

let bases = BaseAddresses::default().set_cfi(0).set_data(0).set_text(0);
let bases = BaseAddresses::default()
.set_eh_frame(0)
.set_got(0)
.set_text(0);

b.iter(|| {
let mut entries = eh_frame.entries(&bases);
Expand All @@ -534,7 +537,10 @@ mod cfi {
let eh_frame = read_section("eh_frame");
let eh_frame = EhFrame::new(&eh_frame, LittleEndian);

let bases = BaseAddresses::default().set_cfi(0).set_data(0).set_text(0);
let bases = BaseAddresses::default()
.set_eh_frame(0)
.set_got(0)
.set_text(0);

b.iter(|| {
let mut entries = eh_frame.entries(&bases);
Expand All @@ -559,7 +565,10 @@ mod cfi {
let eh_frame = read_section("eh_frame");
let eh_frame = EhFrame::new(&eh_frame, LittleEndian);

let bases = BaseAddresses::default().set_cfi(0).set_data(0).set_text(0);
let bases = BaseAddresses::default()
.set_eh_frame(0)
.set_got(0)
.set_text(0);

b.iter(|| {
let mut entries = eh_frame.entries(&bases);
Expand Down Expand Up @@ -594,7 +603,10 @@ mod cfi {
let eh_frame = read_section("eh_frame");
let eh_frame = EhFrame::new(&eh_frame, LittleEndian);

let bases = BaseAddresses::default().set_cfi(0).set_data(0).set_text(0);
let bases = BaseAddresses::default()
.set_eh_frame(0)
.set_got(0)
.set_text(0);

let mut ctx = Some(UninitializedUnwindContext::new());

Expand Down Expand Up @@ -639,7 +651,10 @@ mod cfi {
fn get_fde_with_longest_cfi_instructions<R: Reader>(
eh_frame: &EhFrame<R>,
) -> FrameDescriptionEntry<EhFrame<R>, R, R::Offset> {
let bases = BaseAddresses::default().set_cfi(0).set_data(0).set_text(0);
let bases = BaseAddresses::default()
.set_eh_frame(0)
.set_got(0)
.set_text(0);

let mut longest: Option<(usize, FrameDescriptionEntry<_, _, _>)> = None;

Expand Down
5 changes: 3 additions & 2 deletions examples/dwarfdump.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -629,9 +629,10 @@ fn dump_eh_frame<R: Reader, W: Write>(
// TODO: when grabbing section contents in `dump_file`, we should also grab
// these addresses.
let bases = gimli::BaseAddresses::default()
.set_cfi(0)
.set_eh_frame_hdr(0)
.set_eh_frame(0)
.set_text(0)
.set_data(0);
.set_got(0);

let mut cies = HashMap::new();

Expand Down
160 changes: 104 additions & 56 deletions src/read/cfi.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -135,19 +135,29 @@ impl<R: Reader> EhFrameHdr<R> {
return Err(Error::UnknownVersion(u64::from(version)));
}

let eh_frame_ptr_enc = DwEhPe(reader.read_u8()?);
let fde_count_enc = DwEhPe(reader.read_u8()?);
let table_enc = DwEhPe(reader.read_u8()?);
let eh_frame_ptr_enc = parse_pointer_encoding(&mut reader)?;
let fde_count_enc = parse_pointer_encoding(&mut reader)?;
let table_enc = parse_pointer_encoding(&mut reader)?;

// Omitting this pointer is not valid (defeats the purpose of .eh_frame_hdr entirely)
if eh_frame_ptr_enc == constants::DW_EH_PE_omit {
return Err(Error::UnexpectedNull);
}

let eh_frame_ptr =
parse_encoded_pointer(eh_frame_ptr_enc, bases, address_size, &self.0, &mut reader)?;
let fde_count =
parse_encoded_pointer(fde_count_enc, bases, address_size, &self.0, &mut reader)?;
let eh_frame_ptr = parse_encoded_pointer(
eh_frame_ptr_enc,
&bases.eh_frame_hdr,
address_size,
&self.0,
&mut reader,
)?;
let fde_count = parse_encoded_pointer(
fde_count_enc,
&bases.eh_frame_hdr,
address_size,
&self.0,
&mut reader,
)?;
let fde_count = match fde_count {
Pointer::Direct(c) => c,
Pointer::Indirect(_) => return Err(Error::UnsupportedPointerEncoding),
Expand Down Expand Up @@ -238,7 +248,7 @@ impl<'a, R: Reader + 'a> EhHdrTable<'a, R> {

let pivot = parse_encoded_pointer(
self.hdr.table_enc,
bases,
&bases.eh_frame_hdr,
self.hdr.address_size,
&self.hdr.section,
&mut reader,
Expand Down Expand Up @@ -268,7 +278,7 @@ impl<'a, R: Reader + 'a> EhHdrTable<'a, R> {

parse_encoded_pointer(
self.hdr.table_enc,
bases,
&bases.eh_frame_hdr,
self.hdr.address_size,
&self.hdr.section,
&mut reader,
Expand All @@ -289,10 +299,6 @@ impl<'a, R: Reader + 'a> EhHdrTable<'a, R> {
/// # let eh_frame: EhFrame<EndianRcSlice<NativeEndian>> = unreachable!();
/// # let eh_frame_hdr: ParsedEhFrameHdr<EndianRcSlice<NativeEndian>> = unimplemented!();
/// # let addr = 0;
/// # let address_of_cfi_section_in_memory = unimplemented!();
/// # let address_of_text_section_in_memory = unimplemented!();
/// # let address_of_data_section_in_memory = unimplemented!();
/// # let address_of_the_start_of_current_func = unimplemented!();
/// # let bases = unimplemented!();
/// let table = eh_frame_hdr.table().unwrap();
/// let fde = table.lookup_and_parse(addr, &bases, eh_frame.clone(),
Expand Down Expand Up @@ -567,10 +573,10 @@ pub trait UnwindSection<R: Reader>: Clone + Debug + _UnwindSectionPrivate<R> {
/// // base address isn't provided and a pointer is found that is relative to
/// // it, we will return an `Err`.
/// # let address_of_text_section_in_memory = unimplemented!();
/// # let address_of_data_section_in_memory = unimplemented!();
/// # let address_of_got_section_in_memory = unimplemented!();
/// let bases = BaseAddresses::default()
/// .set_text(address_of_text_section_in_memory)
/// .set_data(address_of_data_section_in_memory);
/// .set_got(address_of_got_section_in_memory);
///
/// let (unwind_info, ctx) = eh_frame.unwind_info_for_address(&bases, ctx, address)
/// .map_err(|(err, ctx)| {
Expand Down Expand Up @@ -774,55 +780,83 @@ impl<R: Reader> UnwindSection<R> for EhFrame<R> {
/// use gimli::BaseAddresses;
///
/// # fn foo() {
/// # let address_of_cfi_section_in_memory = unimplemented!();
/// # let address_of_eh_frame_hdr_section_in_memory = unimplemented!();
/// # let address_of_eh_frame_section_in_memory = unimplemented!();
/// # let address_of_text_section_in_memory = unimplemented!();
/// # let address_of_data_section_in_memory = unimplemented!();
/// # let address_of_got_section_in_memory = unimplemented!();
/// # let address_of_the_start_of_current_func = unimplemented!();
/// let bases = BaseAddresses::default()
/// .set_cfi(address_of_cfi_section_in_memory)
/// .set_eh_frame_hdr(address_of_eh_frame_hdr_section_in_memory)
/// .set_eh_frame(address_of_eh_frame_section_in_memory)
/// .set_text(address_of_text_section_in_memory)
/// .set_data(address_of_data_section_in_memory);
/// .set_got(address_of_got_section_in_memory);
/// # let _ = bases;
/// # }
/// ```
#[derive(Clone, Default, Debug, PartialEq, Eq)]
pub struct BaseAddresses {
/// The address of the current CFI unwind section (`.eh_frame` or
/// `.debug_frame`) in memory.
pub cfi: Option<u64>,
/// The base addresses to use for pointers in the `.eh_frame_hdr` section.
pub eh_frame_hdr: SectionBaseAddresses,

/// The base addresses to use for pointers in the `.eh_frame` section.
pub eh_frame: SectionBaseAddresses,
}

/// Optional base addresses for the relative `DW_EH_PE_*` encoded pointers
/// in a particular section.
///
/// See `BaseAddresses` for methods that are helpful in setting these addresses.
#[derive(Clone, Default, Debug, PartialEq, Eq)]
pub struct SectionBaseAddresses {
/// The address of the section containing the pointer.
pub section: Option<u64>,

/// The address of the `.text` section in memory.
/// The base address for text relative pointers.
/// This is generally the address of the `.text` section.
pub text: Option<u64>,

/// The address of the `.data` section in memory.
/// The base address for data relative pointers.
///
/// For pointers in the `.eh_frame_hdr` section, this is the address
/// of the `.eh_frame_hdr` section
///
/// For pointers in the `.eh_frame` section, this is generally the
/// global pointer, such as the address of the `.got` section.
pub data: Option<u64>,

// Unlike the others, the function base is managed internally to the parser
// as we enter and exit FDE parsing.
#[doc(hidden)]
#[allow(missing_docs)]
pub func: RefCell<Option<u64>>,
pub(crate) func: RefCell<Option<u64>>,
}

impl BaseAddresses {
/// Set the CFI section base address.
/// Set the `.eh_frame_hdr` section base address.
#[inline]
pub fn set_eh_frame_hdr(mut self, addr: u64) -> Self {
self.eh_frame_hdr.section = Some(addr);
self.eh_frame_hdr.data = Some(addr);
self
}

/// Set the `.eh_frame` section base address.
#[inline]
pub fn set_cfi(mut self, addr: u64) -> Self {
self.cfi = Some(addr);
pub fn set_eh_frame(mut self, addr: u64) -> Self {
self.eh_frame.section = Some(addr);
self
}

/// Set the `.text` section base address.
#[inline]
pub fn set_text(mut self, addr: u64) -> Self {
self.text = Some(addr);
self.eh_frame_hdr.text = Some(addr);
self.eh_frame.text = Some(addr);
self
}

/// Set the `.data` section base address.
/// Set the `.got` section base address.
#[inline]
pub fn set_data(mut self, addr: u64) -> Self {
self.data = Some(addr);
pub fn set_got(mut self, addr: u64) -> Self {
self.eh_frame.data = Some(addr);
self
}
}
Expand All @@ -845,15 +879,17 @@ impl BaseAddresses {
/// # let read_eh_frame_somehow = || unimplemented!();
/// let eh_frame = EhFrame::new(read_eh_frame_somehow(), NativeEndian);
///
/// # let address_of_cfi_section_in_memory = unimplemented!();
/// # let address_of_eh_frame_hdr_section_in_memory = unimplemented!();
/// # let address_of_eh_frame_section_in_memory = unimplemented!();
/// # let address_of_text_section_in_memory = unimplemented!();
/// # let address_of_data_section_in_memory = unimplemented!();
/// # let address_of_got_section_in_memory = unimplemented!();
/// # let address_of_the_start_of_current_func = unimplemented!();
/// // Provide base addresses for relative pointers.
/// let bases = BaseAddresses::default()
/// .set_cfi(address_of_cfi_section_in_memory)
/// .set_eh_frame_hdr(address_of_eh_frame_hdr_section_in_memory)
/// .set_eh_frame(address_of_eh_frame_section_in_memory)
/// .set_text(address_of_text_section_in_memory)
/// .set_data(address_of_data_section_in_memory);
/// .set_got(address_of_got_section_in_memory);
///
/// let mut entries = eh_frame.entries(&bases);
///
Expand Down Expand Up @@ -889,7 +925,7 @@ where

// Clear any function relative base address, if one was set when parsing
// the last entry.
self.bases.func.borrow_mut().take();
self.bases.eh_frame.func.borrow_mut().take();

match parse_cfi_entry(self.bases, self.section.clone(), &mut self.input) {
Err(e) => {
Expand Down Expand Up @@ -1099,7 +1135,7 @@ impl Augmentation {
let encoding = parse_pointer_encoding(rest)?;
let personality = parse_encoded_pointer(
encoding,
bases,
&bases.eh_frame,
address_size,
section.section(),
rest,
Expand Down Expand Up @@ -1147,8 +1183,13 @@ impl AugmentationData {
let rest = &mut input.split(aug_data_len)?;
let mut augmentation_data = AugmentationData::default();
if let Some(encoding) = augmentation.lsda {
let lsda =
parse_encoded_pointer(encoding, bases, address_size, section.section(), rest)?;
let lsda = parse_encoded_pointer(
encoding,
&bases.eh_frame,
address_size,
section.section(),
rest,
)?;
augmentation_data.lsda = Some(lsda);
}
Ok(augmentation_data)
Expand Down Expand Up @@ -1497,7 +1538,7 @@ where
F: FnMut(Section::Offset) -> Result<CommonInformationEntry<Section, R, R::Offset>>,
{
{
let mut func = bases.func.borrow_mut();
let mut func = bases.eh_frame.func.borrow_mut();
let offset = rest.offset_from(section.section());
*func = Some(offset.into_u64());
}
Expand Down Expand Up @@ -1548,8 +1589,13 @@ where
) -> Result<(u64, u64)> {
let encoding = cie.augmentation().and_then(|a| a.fde_address_encoding);
if let Some(encoding) = encoding {
let initial_address =
parse_encoded_pointer(encoding, bases, cie.address_size, section.section(), input)?;
let initial_address = parse_encoded_pointer(
encoding,
&bases.eh_frame,
cie.address_size,
section.section(),
input,
)?;

// Ignore indirection.
let initial_address = initial_address.into();
Expand All @@ -1558,7 +1604,7 @@ where
// data format bits from the encoding.
let address_range = parse_encoded_pointer(
encoding.format(),
bases,
&bases.eh_frame,
cie.address_size,
section.section(),
input,
Expand Down Expand Up @@ -6406,21 +6452,23 @@ mod tests {
#[cfg(target_pointer_width = "64")]
fn size_of_unwind_ctx() {
use std::mem;
assert_eq!(
mem::size_of::<
UnwindContext<EhFrame<EndianSlice<NativeEndian>>, EndianSlice<NativeEndian>>,
>(),
5416
);
let size = mem::size_of::<
UnwindContext<EhFrame<EndianSlice<NativeEndian>>, EndianSlice<NativeEndian>>,
>();
let max_size = 5416;
if size > max_size {
assert_eq!(size, max_size);
}
}

#[test]
#[cfg(target_pointer_width = "64")]
fn size_of_register_rule_map() {
use std::mem;
assert_eq!(
mem::size_of::<RegisterRuleMap<EndianSlice<NativeEndian>>>(),
1040
);
let size = mem::size_of::<RegisterRuleMap<EndianSlice<NativeEndian>>>();
let max_size = 1040;
if size > max_size {
assert_eq!(size, max_size);
}
}
}
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