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/*
* Copyright (c) 2020, Linus Groh <linusg@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/LexicalPath.h>
#include <AK/MappedFile.h>
#include <AK/Platform.h>
#include <AK/StringBuilder.h>
#include <AK/Types.h>
#include <LibCore/File.h>
#include <LibCoredump/Backtrace.h>
#include <LibCoredump/Reader.h>
#include <LibELF/Core.h>
#include <LibELF/Image.h>
namespace Coredump {
ELFObjectInfo const* Backtrace::object_info_for_region(ELF::Core::MemoryRegionInfo const& region)
{
auto path = region.object_name();
if (!path.starts_with('/') && Core::File::looks_like_shared_library(path))
path = LexicalPath::join("/usr/lib", path).string();
auto maybe_ptr = m_debug_info_cache.get(path);
if (maybe_ptr.has_value())
return *maybe_ptr;
if (!Core::File::exists(path))
return nullptr;
auto file_or_error = MappedFile::map(path);
if (file_or_error.is_error())
return nullptr;
auto image = make<ELF::Image>(file_or_error.value()->bytes());
auto& image_reference = *image;
auto info = make<ELFObjectInfo>(file_or_error.release_value(), make<Debug::DebugInfo>(image_reference), move(image));
auto* info_ptr = info.ptr();
m_debug_info_cache.set(path, move(info));
return info_ptr;
}
Backtrace::Backtrace(const Reader& coredump, const ELF::Core::ThreadInfo& thread_info, Function<void(size_t, size_t)> on_progress)
: m_thread_info(move(thread_info))
{
#if ARCH(I386)
auto* start_bp = (FlatPtr*)m_thread_info.regs.ebp;
auto* start_ip = (FlatPtr*)m_thread_info.regs.eip;
#else
auto* start_bp = (FlatPtr*)m_thread_info.regs.rbp;
auto* start_ip = (FlatPtr*)m_thread_info.regs.rip;
#endif
// In order to provide progress updates, we first have to walk the
// call stack to determine how many frames it has.
size_t frame_count = 0;
{
auto* bp = start_bp;
auto* ip = start_ip;
while (bp && ip) {
++frame_count;
auto next_ip = coredump.peek_memory((FlatPtr)(bp + 1));
auto next_bp = coredump.peek_memory((FlatPtr)(bp));
if (!next_ip.has_value() || !next_bp.has_value())
break;
ip = (FlatPtr*)next_ip.value();
bp = (FlatPtr*)next_bp.value();
}
}
auto* bp = start_bp;
auto* ip = start_ip;
size_t frame_index = 0;
while (bp && ip) {
// We use eip - 1 because the return address from a function frame
// is the instruction that comes after the 'call' instruction.
// However, because the first frame represents the faulting
// instruction rather than the return address we don't subtract
// 1 there.
VERIFY((FlatPtr)ip > 0);
add_entry(coredump, (FlatPtr)ip - ((frame_index == 0) ? 0 : 1));
if (on_progress)
on_progress(frame_index, frame_count);
++frame_index;
auto next_ip = coredump.peek_memory((FlatPtr)(bp + 1));
auto next_bp = coredump.peek_memory((FlatPtr)(bp));
if (!next_ip.has_value() || !next_bp.has_value())
break;
ip = (FlatPtr*)next_ip.value();
bp = (FlatPtr*)next_bp.value();
}
}
Backtrace::~Backtrace()
{
}
void Backtrace::add_entry(const Reader& coredump, FlatPtr ip)
{
auto* ip_region = coredump.region_containing((FlatPtr)ip);
if (!ip_region) {
m_entries.append({ ip, {}, {}, {} });
return;
}
auto object_name = ip_region->object_name();
// Only skip addresses coming from Loader.so if the faulting instruction is not in Loader.so
if (object_name == "Loader.so") {
if (m_skip_loader_so)
return;
} else {
m_skip_loader_so = true;
}
// We need to find the first region for the object, just in case
// the PT_LOAD header for the .text segment isn't the first one
// in the object file.
auto region = coredump.first_region_for_object(object_name);
auto* object_info = object_info_for_region(*region);
if (!object_info)
return;
auto function_name = object_info->debug_info->elf().symbolicate(ip - region->region_start);
auto source_position = object_info->debug_info->get_source_position_with_inlines(ip - region->region_start);
m_entries.append({ ip, object_name, function_name, source_position });
}
String Backtrace::Entry::to_string(bool color) const
{
StringBuilder builder;
builder.appendff("{:p}: ", eip);
if (object_name.is_empty()) {
builder.append("???");
return builder.build();
}
builder.appendff("[{}] {}", object_name, function_name.is_empty() ? "???" : function_name);
builder.append(" (");
Vector<Debug::DebugInfo::SourcePosition> source_positions;
for (auto& position : source_position_with_inlines.inline_chain) {
if (!source_positions.contains_slow(position))
source_positions.append(position);
}
if (source_position_with_inlines.source_position.has_value() && !source_positions.contains_slow(source_position_with_inlines.source_position.value())) {
source_positions.insert(0, source_position_with_inlines.source_position.value());
}
for (size_t i = 0; i < source_positions.size(); ++i) {
auto& position = source_positions[i];
auto fmt = color ? "\033[34;1m{}\033[0m:{}" : "{}:{}";
builder.appendff(fmt, LexicalPath::basename(position.file_path), position.line_number);
if (i != source_positions.size() - 1) {
builder.append(" => ");
}
}
builder.append(")");
return builder.build();
}
}
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