platform_system_core/libunwindstack/DwarfEhFrameWithHdr.h
Christopher Ferris 4ca98e18a4 Fix potential bad info in eh_frame_hdr.
Due to a bug, an elf can have FDEs with a length of zero, while still
having another FDE for the same pc with a non-zero length. The
eh_frame_hdr can sometimes point to the zero length FDE, but it should
have pointed to the non-zero length FDE. In order to fix this, if the
eh_frame_hdr points at the zero length FDE then try and find the real FDE
directly from eh_frame.

The change cleans up and removes unused variables from DwarfEhFrameWithHdr
and changes the objects so that all of the DwarfSection objects and
DwarfEhFrameWithHdr object inherit from the same class.

Add new unit tests to verify this functionality.

Bug: 142483624

Test: Unit tests all pass.
Change-Id: I128a916e3ba378931de7d44ee15e57e24d4073df
2019-10-29 18:39:30 -07:00

86 lines
2.5 KiB
C++

/*
* Copyright (C) 2016 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef _LIBUNWINDSTACK_DWARF_EH_FRAME_WITH_HDR_H
#define _LIBUNWINDSTACK_DWARF_EH_FRAME_WITH_HDR_H
#include <stdint.h>
#include <unordered_map>
#include <unwindstack/DwarfSection.h>
namespace unwindstack {
// Forward declarations.
class Memory;
template <typename AddressType>
class DwarfEhFrameWithHdr : public DwarfSectionImpl<AddressType> {
public:
// Add these so that the protected members of DwarfSectionImpl
// can be accessed without needing a this->.
using DwarfSectionImpl<AddressType>::memory_;
using DwarfSectionImpl<AddressType>::last_error_;
struct FdeInfo {
AddressType pc;
uint64_t offset;
};
DwarfEhFrameWithHdr(Memory* memory) : DwarfSectionImpl<AddressType>(memory) {}
virtual ~DwarfEhFrameWithHdr() = default;
uint64_t GetCieOffsetFromFde32(uint32_t pointer) override {
return memory_.cur_offset() - pointer - 4;
}
uint64_t GetCieOffsetFromFde64(uint64_t pointer) override {
return memory_.cur_offset() - pointer - 8;
}
uint64_t AdjustPcFromFde(uint64_t pc) override {
// The eh_frame uses relative pcs.
return pc + memory_.cur_offset() - 4;
}
bool EhFrameInit(uint64_t offset, uint64_t size, int64_t section_bias);
bool Init(uint64_t offset, uint64_t size, int64_t section_bias) override;
const DwarfFde* GetFdeFromPc(uint64_t pc) override;
bool GetFdeOffsetFromPc(uint64_t pc, uint64_t* fde_offset);
const FdeInfo* GetFdeInfoFromIndex(size_t index);
void GetFdes(std::vector<const DwarfFde*>* fdes) override;
protected:
uint8_t version_ = 0;
uint8_t table_encoding_ = 0;
size_t table_entry_size_ = 0;
uint64_t hdr_entries_offset_ = 0;
uint64_t hdr_entries_data_offset_ = 0;
uint64_t hdr_section_bias_ = 0;
uint64_t fde_count_ = 0;
std::unordered_map<uint64_t, FdeInfo> fde_info_;
};
} // namespace unwindstack
#endif // _LIBUNWINDSTACK_DWARF_EH_FRAME_WITH_HDR_H