From 698f8c2f01ea549d77d7dc3338a12e04c11057b9 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Wed, 17 Apr 2024 14:02:58 +0200 Subject: Adding upstream version 1.64.0+dfsg1. Signed-off-by: Daniel Baumann --- library/backtrace/src/symbolize/gimli/macho.rs | 324 +++++++++++++++++++++++++ 1 file changed, 324 insertions(+) create mode 100644 library/backtrace/src/symbolize/gimli/macho.rs (limited to 'library/backtrace/src/symbolize/gimli/macho.rs') diff --git a/library/backtrace/src/symbolize/gimli/macho.rs b/library/backtrace/src/symbolize/gimli/macho.rs new file mode 100644 index 000000000..ec5673843 --- /dev/null +++ b/library/backtrace/src/symbolize/gimli/macho.rs @@ -0,0 +1,324 @@ +use super::{Box, Context, Mapping, Path, Stash, Vec}; +use core::convert::TryInto; +use object::macho; +use object::read::macho::{MachHeader, Nlist, Section, Segment as _}; +use object::{Bytes, NativeEndian}; + +#[cfg(target_pointer_width = "32")] +type Mach = object::macho::MachHeader32; +#[cfg(target_pointer_width = "64")] +type Mach = object::macho::MachHeader64; +type MachSegment = ::Segment; +type MachSection = ::Section; +type MachNlist = ::Nlist; + +impl Mapping { + // The loading path for OSX is is so different we just have a completely + // different implementation of the function here. On OSX we need to go + // probing the filesystem for a bunch of files. + pub fn new(path: &Path) -> Option { + // First up we need to load the unique UUID which is stored in the macho + // header of the file we're reading, specified at `path`. + let map = super::mmap(path)?; + let (macho, data) = find_header(&map)?; + let endian = macho.endian().ok()?; + let uuid = macho.uuid(endian, data, 0).ok()?; + + // Next we need to look for a `*.dSYM` file. For now we just probe the + // containing directory and look around for something that matches + // `*.dSYM`. Once it's found we root through the dwarf resources that it + // contains and try to find a macho file which has a matching UUID as + // the one of our own file. If we find a match that's the dwarf file we + // want to return. + if let Some(uuid) = uuid { + if let Some(parent) = path.parent() { + if let Some(mapping) = Mapping::load_dsym(parent, uuid) { + return Some(mapping); + } + } + } + + // Looks like nothing matched our UUID, so let's at least return our own + // file. This should have the symbol table for at least some + // symbolication purposes. + Mapping::mk(map, |data, stash| { + let (macho, data) = find_header(data)?; + let endian = macho.endian().ok()?; + let obj = Object::parse(macho, endian, data)?; + Context::new(stash, obj, None) + }) + } + + fn load_dsym(dir: &Path, uuid: [u8; 16]) -> Option { + for entry in dir.read_dir().ok()? { + let entry = entry.ok()?; + let filename = match entry.file_name().into_string() { + Ok(name) => name, + Err(_) => continue, + }; + if !filename.ends_with(".dSYM") { + continue; + } + let candidates = entry.path().join("Contents/Resources/DWARF"); + if let Some(mapping) = Mapping::try_dsym_candidate(&candidates, uuid) { + return Some(mapping); + } + } + None + } + + fn try_dsym_candidate(dir: &Path, uuid: [u8; 16]) -> Option { + // Look for files in the `DWARF` directory which have a matching uuid to + // the original object file. If we find one then we found the debug + // information. + for entry in dir.read_dir().ok()? { + let entry = entry.ok()?; + let map = super::mmap(&entry.path())?; + let candidate = Mapping::mk(map, |data, stash| { + let (macho, data) = find_header(data)?; + let endian = macho.endian().ok()?; + let entry_uuid = macho.uuid(endian, data, 0).ok()??; + if entry_uuid != uuid { + return None; + } + let obj = Object::parse(macho, endian, data)?; + Context::new(stash, obj, None) + }); + if let Some(candidate) = candidate { + return Some(candidate); + } + } + + None + } +} + +fn find_header(data: &'_ [u8]) -> Option<(&'_ Mach, &'_ [u8])> { + use object::endian::BigEndian; + + let desired_cpu = || { + if cfg!(target_arch = "x86") { + Some(macho::CPU_TYPE_X86) + } else if cfg!(target_arch = "x86_64") { + Some(macho::CPU_TYPE_X86_64) + } else if cfg!(target_arch = "arm") { + Some(macho::CPU_TYPE_ARM) + } else if cfg!(target_arch = "aarch64") { + Some(macho::CPU_TYPE_ARM64) + } else { + None + } + }; + + let mut data = Bytes(data); + match data + .clone() + .read::>() + .ok()? + .get(NativeEndian) + { + macho::MH_MAGIC_64 | macho::MH_CIGAM_64 | macho::MH_MAGIC | macho::MH_CIGAM => {} + + macho::FAT_MAGIC | macho::FAT_CIGAM => { + let mut header_data = data; + let endian = BigEndian; + let header = header_data.read::().ok()?; + let nfat = header.nfat_arch.get(endian); + let arch = (0..nfat) + .filter_map(|_| header_data.read::().ok()) + .find(|arch| desired_cpu() == Some(arch.cputype.get(endian)))?; + let offset = arch.offset.get(endian); + let size = arch.size.get(endian); + data = data + .read_bytes_at(offset.try_into().ok()?, size.try_into().ok()?) + .ok()?; + } + + macho::FAT_MAGIC_64 | macho::FAT_CIGAM_64 => { + let mut header_data = data; + let endian = BigEndian; + let header = header_data.read::().ok()?; + let nfat = header.nfat_arch.get(endian); + let arch = (0..nfat) + .filter_map(|_| header_data.read::().ok()) + .find(|arch| desired_cpu() == Some(arch.cputype.get(endian)))?; + let offset = arch.offset.get(endian); + let size = arch.size.get(endian); + data = data + .read_bytes_at(offset.try_into().ok()?, size.try_into().ok()?) + .ok()?; + } + + _ => return None, + } + + Mach::parse(data.0, 0).ok().map(|h| (h, data.0)) +} + +// This is used both for executables/libraries and source object files. +pub struct Object<'a> { + endian: NativeEndian, + data: &'a [u8], + dwarf: Option<&'a [MachSection]>, + syms: Vec<(&'a [u8], u64)>, + syms_sort_by_name: bool, + // Only set for executables/libraries, and not the source object files. + object_map: Option>, + // The outer Option is for lazy loading, and the inner Option allows load errors to be cached. + object_mappings: Box<[Option>]>, +} + +impl<'a> Object<'a> { + fn parse(mach: &'a Mach, endian: NativeEndian, data: &'a [u8]) -> Option> { + let is_object = mach.filetype(endian) == object::macho::MH_OBJECT; + let mut dwarf = None; + let mut syms = Vec::new(); + let mut syms_sort_by_name = false; + let mut commands = mach.load_commands(endian, data, 0).ok()?; + let mut object_map = None; + let mut object_mappings = Vec::new(); + while let Ok(Some(command)) = commands.next() { + if let Some((segment, section_data)) = MachSegment::from_command(command).ok()? { + // Object files should have all sections in a single unnamed segment load command. + if segment.name() == b"__DWARF" || (is_object && segment.name() == b"") { + dwarf = segment.sections(endian, section_data).ok(); + } + } else if let Some(symtab) = command.symtab().ok()? { + let symbols = symtab.symbols::(endian, data).ok()?; + syms = symbols + .iter() + .filter_map(|nlist: &MachNlist| { + let name = nlist.name(endian, symbols.strings()).ok()?; + if name.len() > 0 && nlist.is_definition() { + Some((name, u64::from(nlist.n_value(endian)))) + } else { + None + } + }) + .collect(); + if is_object { + // We never search object file symbols by address. + // Instead, we already know the symbol name from the executable, and we + // need to search by name to find the matching symbol in the object file. + syms.sort_unstable_by_key(|(name, _)| *name); + syms_sort_by_name = true; + } else { + syms.sort_unstable_by_key(|(_, addr)| *addr); + let map = symbols.object_map(endian); + object_mappings.resize_with(map.objects().len(), || None); + object_map = Some(map); + } + } + } + + Some(Object { + endian, + data, + dwarf, + syms, + syms_sort_by_name, + object_map, + object_mappings: object_mappings.into_boxed_slice(), + }) + } + + pub fn section(&self, _: &Stash, name: &str) -> Option<&'a [u8]> { + let name = name.as_bytes(); + let dwarf = self.dwarf?; + let section = dwarf.into_iter().find(|section| { + let section_name = section.name(); + section_name == name || { + section_name.starts_with(b"__") + && name.starts_with(b".") + && §ion_name[2..] == &name[1..] + } + })?; + Some(section.data(self.endian, self.data).ok()?) + } + + pub fn search_symtab<'b>(&'b self, addr: u64) -> Option<&'b [u8]> { + debug_assert!(!self.syms_sort_by_name); + let i = match self.syms.binary_search_by_key(&addr, |(_, addr)| *addr) { + Ok(i) => i, + Err(i) => i.checked_sub(1)?, + }; + let (sym, _addr) = self.syms.get(i)?; + Some(sym) + } + + /// Try to load a context for an object file. + /// + /// If dsymutil was not run, then the DWARF may be found in the source object files. + pub(super) fn search_object_map<'b>(&'b mut self, addr: u64) -> Option<(&Context<'b>, u64)> { + // `object_map` contains a map from addresses to symbols and object paths. + // Look up the address and get a mapping for the object. + let object_map = self.object_map.as_ref()?; + let symbol = object_map.get(addr)?; + let object_index = symbol.object_index(); + let mapping = self.object_mappings.get_mut(object_index)?; + if mapping.is_none() { + // No cached mapping, so create it. + *mapping = Some(object_mapping(object_map.objects().get(object_index)?)); + } + let cx: &'b Context<'static> = &mapping.as_ref()?.as_ref()?.cx; + // Don't leak the `'static` lifetime, make sure it's scoped to just ourselves. + let cx = unsafe { core::mem::transmute::<&'b Context<'static>, &'b Context<'b>>(cx) }; + + // We must translate the address in order to be able to look it up + // in the DWARF in the object file. + debug_assert!(cx.object.syms.is_empty() || cx.object.syms_sort_by_name); + let i = cx + .object + .syms + .binary_search_by_key(&symbol.name(), |(name, _)| *name) + .ok()?; + let object_symbol = cx.object.syms.get(i)?; + let object_addr = addr + .wrapping_sub(symbol.address()) + .wrapping_add(object_symbol.1); + Some((cx, object_addr)) + } +} + +fn object_mapping(path: &[u8]) -> Option { + use super::mystd::ffi::OsStr; + use super::mystd::os::unix::prelude::*; + + let map; + + // `N_OSO` symbol names can be either `/path/to/object.o` or `/path/to/archive.a(object.o)`. + let member_name = if let Some((archive_path, member_name)) = split_archive_path(path) { + map = super::mmap(Path::new(OsStr::from_bytes(archive_path)))?; + Some(member_name) + } else { + map = super::mmap(Path::new(OsStr::from_bytes(path)))?; + None + }; + Mapping::mk(map, |data, stash| { + let data = match member_name { + Some(member_name) => { + let archive = object::read::archive::ArchiveFile::parse(data).ok()?; + let member = archive + .members() + .filter_map(Result::ok) + .find(|m| m.name() == member_name)?; + member.data(data).ok()? + } + None => data, + }; + let (macho, data) = find_header(data)?; + let endian = macho.endian().ok()?; + let obj = Object::parse(macho, endian, data)?; + Context::new(stash, obj, None) + }) +} + +fn split_archive_path(path: &[u8]) -> Option<(&[u8], &[u8])> { + let (last, path) = path.split_last()?; + if *last != b')' { + return None; + } + let index = path.iter().position(|&x| x == b'(')?; + let (archive, rest) = path.split_at(index); + Some((archive, &rest[1..])) +} -- cgit v1.2.3