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Commit c9dee84d authored by Christopher Ferris's avatar Christopher Ferris
Browse files

Add support for only a .eh_frame. 

Static executables only have a .eh_frame section and no .eh_frame_hdr
section. Add support for this by rearranging the class hierarchy and
creating a DwarfEhFrameWithHdr class and a DwarfEhFrame class to handle
the different cases.

Add new unit tests for DwarfEhFrame and for the new functionality.

Bug: 68820189

Test: Passes new unit tests, unwinds static executables.
Change-Id: I63d7cb8c52a686e96579a2266e18c0d06bbb6e63
parent 1e0b9672

libunwindstack/Android.bp

+2 −2
Original line number Diff line number Diff line
@@ -48,8 +48,7 @@ cc_library { 
    srcs: [

        "ArmExidx.cpp",

        "DwarfCfa.cpp",

        "DwarfDebugFrame.cpp",

        "DwarfEhFrame.cpp",

        "DwarfEhFrameWithHdr.cpp",

        "DwarfMemory.cpp",

        "DwarfOp.cpp",

        "DwarfSection.cpp",
@@ -106,6 +105,7 @@ cc_test { 
        "tests/DwarfCfaTest.cpp",

        "tests/DwarfDebugFrameTest.cpp",

        "tests/DwarfEhFrameTest.cpp",

        "tests/DwarfEhFrameWithHdrTest.cpp",

        "tests/DwarfMemoryTest.cpp",

        "tests/DwarfOpLogTest.cpp",

        "tests/DwarfOpTest.cpp",

libunwindstack/DwarfDebugFrame.cpp

deleted100644 → 0
+0 −316
Original line number Diff line number Diff line 
/*

 * Copyright (C) 2017 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.

 */



#include <stdint.h>

#include <stdlib.h>



#include <algorithm>



#include <unwindstack/DwarfStructs.h>

#include <unwindstack/Memory.h>



#include "DwarfDebugFrame.h"

#include "DwarfEncoding.h"

#include "DwarfError.h"



namespace unwindstack {



template <typename AddressType>

bool DwarfDebugFrame<AddressType>::Init(uint64_t offset, uint64_t size) {

  offset_ = offset;

  end_offset_ = offset + size;



  memory_.clear_func_offset();

  memory_.clear_text_offset();

  memory_.set_data_offset(offset);

  memory_.set_cur_offset(offset);



  return CreateSortedFdeList();

}



template <typename AddressType>

bool DwarfDebugFrame<AddressType>::GetCieInfo(uint8_t* segment_size, uint8_t* encoding) {

  uint8_t version;

  if (!memory_.ReadBytes(&version, 1)) {

    last_error_ = DWARF_ERROR_MEMORY_INVALID;

    return false;

  }

  // Read the augmentation string.

  std::vector<char> aug_string;

  char aug_value;

  bool get_encoding = false;

  do {

    if (!memory_.ReadBytes(&aug_value, 1)) {

      last_error_ = DWARF_ERROR_MEMORY_INVALID;

      return false;

    }

    if (aug_value == 'R') {

      get_encoding = true;

    }

    aug_string.push_back(aug_value);

  } while (aug_value != '\0');



  if (version == 4) {

    // Skip the Address Size field.

    memory_.set_cur_offset(memory_.cur_offset() + 1);



    // Read the segment size.

    if (!memory_.ReadBytes(segment_size, 1)) {

      last_error_ = DWARF_ERROR_MEMORY_INVALID;

      return false;

    }

  } else {

    *segment_size = 0;

  }



  if (aug_string[0] != 'z' || !get_encoding) {

    // No encoding

    return true;

  }



  // Skip code alignment factor

  uint8_t value;

  do {

    if (!memory_.ReadBytes(&value, 1)) {

      last_error_ = DWARF_ERROR_MEMORY_INVALID;

      return false;

    }

  } while (value & 0x80);



  // Skip data alignment factor

  do {

    if (!memory_.ReadBytes(&value, 1)) {

      last_error_ = DWARF_ERROR_MEMORY_INVALID;

      return false;

    }

  } while (value & 0x80);



  if (version == 1) {

    // Skip return address register.

    memory_.set_cur_offset(memory_.cur_offset() + 1);

  } else {

    // Skip return address register.

    do {

      if (!memory_.ReadBytes(&value, 1)) {

        last_error_ = DWARF_ERROR_MEMORY_INVALID;

        return false;

      }

    } while (value & 0x80);

  }



  // Skip the augmentation length.

  do {

    if (!memory_.ReadBytes(&value, 1)) {

      last_error_ = DWARF_ERROR_MEMORY_INVALID;

      return false;

    }

  } while (value & 0x80);



  for (size_t i = 1; i < aug_string.size(); i++) {

    if (aug_string[i] == 'R') {

      if (!memory_.ReadBytes(encoding, 1)) {

        last_error_ = DWARF_ERROR_MEMORY_INVALID;

        return false;

      }

      // Got the encoding, that's all we are looking for.

      return true;

    } else if (aug_string[i] == 'L') {

      memory_.set_cur_offset(memory_.cur_offset() + 1);

    } else if (aug_string[i] == 'P') {

      uint8_t encoding;

      if (!memory_.ReadBytes(&encoding, 1)) {

        last_error_ = DWARF_ERROR_MEMORY_INVALID;

        return false;

      }

      uint64_t value;

      if (!memory_.template ReadEncodedValue<AddressType>(encoding, &value)) {

        last_error_ = DWARF_ERROR_MEMORY_INVALID;

        return false;

      }

    }

  }



  // It should be impossible to get here.

  abort();

}



template <typename AddressType>

bool DwarfDebugFrame<AddressType>::AddFdeInfo(uint64_t entry_offset, uint8_t segment_size,

                                              uint8_t encoding) {

  if (segment_size != 0) {

    memory_.set_cur_offset(memory_.cur_offset() + 1);

  }



  uint64_t start;

  if (!memory_.template ReadEncodedValue<AddressType>(encoding & 0xf, &start)) {

    last_error_ = DWARF_ERROR_MEMORY_INVALID;

    return false;

  }



  uint64_t length;

  if (!memory_.template ReadEncodedValue<AddressType>(encoding & 0xf, &length)) {

    last_error_ = DWARF_ERROR_MEMORY_INVALID;

    return false;

  }

  if (length != 0) {

    fdes_.emplace_back(entry_offset, start, length);

  }



  return true;

}



template <typename AddressType>

bool DwarfDebugFrame<AddressType>::CreateSortedFdeList() {

  memory_.set_cur_offset(offset_);



  // Loop through all of the entries and read just enough to create

  // a sorted list of pcs.

  // This code assumes that first comes the cie, then the fdes that

  // it applies to.

  uint64_t cie_offset = 0;

  uint8_t address_encoding;

  uint8_t segment_size;

  while (memory_.cur_offset() < end_offset_) {

    uint64_t cur_entry_offset = memory_.cur_offset();



    // Figure out the entry length and type.

    uint32_t value32;

    if (!memory_.ReadBytes(&value32, sizeof(value32))) {

      last_error_ = DWARF_ERROR_MEMORY_INVALID;

      return false;

    }



    uint64_t next_entry_offset;

    if (value32 == static_cast<uint32_t>(-1)) {

      uint64_t value64;

      if (!memory_.ReadBytes(&value64, sizeof(value64))) {

        last_error_ = DWARF_ERROR_MEMORY_INVALID;

        return false;

      }

      next_entry_offset = memory_.cur_offset() + value64;



      // Read the Cie Id of a Cie or the pointer of the Fde.

      if (!memory_.ReadBytes(&value64, sizeof(value64))) {

        last_error_ = DWARF_ERROR_MEMORY_INVALID;

        return false;

      }



      if (value64 == static_cast<uint64_t>(-1)) {

        // Cie 64 bit

        address_encoding = DW_EH_PE_sdata8;

        if (!GetCieInfo(&segment_size, &address_encoding)) {

          return false;

        }

        cie_offset = cur_entry_offset;

      } else {

        if (offset_ + value64 != cie_offset) {

          // This means that this Fde is not following the Cie.

          last_error_ = DWARF_ERROR_ILLEGAL_VALUE;

          return false;

        }



        // Fde 64 bit

        if (!AddFdeInfo(cur_entry_offset, segment_size, address_encoding)) {

          return false;

        }

      }

    } else {

      next_entry_offset = memory_.cur_offset() + value32;



      // Read the Cie Id of a Cie or the pointer of the Fde.

      if (!memory_.ReadBytes(&value32, sizeof(value32))) {

        last_error_ = DWARF_ERROR_MEMORY_INVALID;

        return false;

      }



      if (value32 == static_cast<uint32_t>(-1)) {

        // Cie 32 bit

        address_encoding = DW_EH_PE_sdata4;

        if (!GetCieInfo(&segment_size, &address_encoding)) {

          return false;

        }

        cie_offset = cur_entry_offset;

      } else {

        if (offset_ + value32 != cie_offset) {

          // This means that this Fde is not following the Cie.

          last_error_ = DWARF_ERROR_ILLEGAL_VALUE;

          return false;

        }



        // Fde 32 bit

        if (!AddFdeInfo(cur_entry_offset, segment_size, address_encoding)) {

          return false;

        }

      }

    }



    if (next_entry_offset < memory_.cur_offset()) {

      // This indicates some kind of corruption, or malformed section data.

      last_error_ = DWARF_ERROR_ILLEGAL_VALUE;

      return false;

    }

    memory_.set_cur_offset(next_entry_offset);

  }



  // Sort the entries.

  std::sort(fdes_.begin(), fdes_.end(), [](const FdeInfo& a, const FdeInfo& b) {

    if (a.start == b.start) return a.end < b.end;

    return a.start < b.start;

  });



  fde_count_ = fdes_.size();



  return true;

}



template <typename AddressType>

bool DwarfDebugFrame<AddressType>::GetFdeOffsetFromPc(uint64_t pc, uint64_t* fde_offset) {

  if (fde_count_ == 0) {

    return false;

  }



  size_t first = 0;

  size_t last = fde_count_;

  while (first < last) {

    size_t current = (first + last) / 2;

    const FdeInfo* info = &fdes_[current];

    if (pc >= info->start && pc <= info->end) {

      *fde_offset = info->offset;

      return true;

    }



    if (pc < info->start) {

      last = current;

    } else {

      first = current + 1;

    }

  }

  return false;

}



template <typename AddressType>

const DwarfFde* DwarfDebugFrame<AddressType>::GetFdeFromIndex(size_t index) {

  if (index >= fdes_.size()) {

    return nullptr;

  }

  return this->GetFdeFromOffset(fdes_[index].offset);

}



// Explicitly instantiate DwarfDebugFrame.

template class DwarfDebugFrame<uint32_t>;

template class DwarfDebugFrame<uint64_t>;



}  // namespace unwindstack

libunwindstack/DwarfDebugFrame.h

+10 −40
Original line number Diff line number Diff line
@@ -28,51 +28,21 @@ namespace unwindstack { 
template <typename AddressType>

class DwarfDebugFrame : 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>::fde_count_;

  using DwarfSectionImpl<AddressType>::last_error_;



  struct FdeInfo {

    FdeInfo(uint64_t offset, uint64_t start, uint64_t length)

        : offset(offset), start(start), end(start + length) {}



    uint64_t offset;

    AddressType start;

    AddressType end;

  };



  DwarfDebugFrame(Memory* memory) : DwarfSectionImpl<AddressType>(memory) {}

  DwarfDebugFrame(Memory* memory) : DwarfSectionImpl<AddressType>(memory) {

    this->cie32_value_ = static_cast<uint32_t>(-1);

    this->cie64_value_ = static_cast<uint64_t>(-1);

  }

  virtual ~DwarfDebugFrame() = default;



  bool Init(uint64_t offset, uint64_t size) override;



  bool GetFdeOffsetFromPc(uint64_t pc, uint64_t* fde_offset) override;



  const DwarfFde* GetFdeFromIndex(size_t index) override;



  bool IsCie32(uint32_t value32) override { return value32 == static_cast<uint32_t>(-1); }

  uint64_t GetCieOffsetFromFde32(uint32_t pointer) override {

    return this->entries_offset_ + pointer;

  }



  bool IsCie64(uint64_t value64) override { return value64 == static_cast<uint64_t>(-1); }



  uint64_t GetCieOffsetFromFde32(uint32_t pointer) override { return offset_ + pointer; }



  uint64_t GetCieOffsetFromFde64(uint64_t pointer) override { return offset_ + pointer; }

  uint64_t GetCieOffsetFromFde64(uint64_t pointer) override {

    return this->entries_offset_ + pointer;

  }



  uint64_t AdjustPcFromFde(uint64_t pc) override { return pc; }



  bool GetCieInfo(uint8_t* segment_size, uint8_t* encoding);



  bool AddFdeInfo(uint64_t entry_offset, uint8_t segment_size, uint8_t encoding);



  bool CreateSortedFdeList();



 protected:

  uint64_t offset_;

  uint64_t end_offset_;



  std::vector<FdeInfo> fdes_;

};



}  // namespace unwindstack

libunwindstack/DwarfEhFrame.h

+5 −49
Original line number Diff line number Diff line
@@ -20,74 +20,30 @@ 
#include <stdint.h>



#include <unwindstack/DwarfSection.h>

#include <unwindstack/Memory.h>



namespace unwindstack {



// Forward declarations.

class Memory;



template <typename AddressType>

class DwarfEhFrame : 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>::fde_count_;

  using DwarfSectionImpl<AddressType>::last_error_;



  struct FdeInfo {

    AddressType pc;

    uint64_t offset;

  };



  DwarfEhFrame(Memory* memory) : DwarfSectionImpl<AddressType>(memory) {}

  virtual ~DwarfEhFrame() = default;



  bool Init(uint64_t offset, uint64_t size) override;



  bool GetFdeOffsetFromPc(uint64_t pc, uint64_t* fde_offset) override;



  const DwarfFde* GetFdeFromIndex(size_t index) override;



  bool IsCie32(uint32_t value32) override { return value32 == 0; }



  bool IsCie64(uint64_t value64) override { return value64 == 0; }



  uint64_t GetCieOffsetFromFde32(uint32_t pointer) override {

    return memory_.cur_offset() - pointer - 4;

    return this->memory_.cur_offset() - pointer - 4;

  }



  uint64_t GetCieOffsetFromFde64(uint64_t pointer) override {

    return memory_.cur_offset() - pointer - 8;

    return this->memory_.cur_offset() - pointer - 8;

  }



  uint64_t AdjustPcFromFde(uint64_t pc) override {

    // The eh_frame uses relative pcs.

    return pc + memory_.cur_offset();

    return pc + this->memory_.cur_offset();

  }



  const FdeInfo* GetFdeInfoFromIndex(size_t index);



  bool GetFdeOffsetSequential(uint64_t pc, uint64_t* fde_offset);



  bool GetFdeOffsetBinary(uint64_t pc, uint64_t* fde_offset, uint64_t total_entries);



 protected:

  uint8_t version_;

  uint8_t ptr_encoding_;

  uint8_t table_encoding_;

  size_t table_entry_size_;



  uint64_t ptr_offset_;



  uint64_t entries_offset_;

  uint64_t entries_end_;

  uint64_t entries_data_offset_;

  uint64_t cur_entries_offset_ = 0;



  std::unordered_map<uint64_t, FdeInfo> fde_info_;

};



}  // namespace unwindstack



#endif  // _LIBUNWINDSTACK_DWARF_EH_FRAME_H
 
#endif  // _LIBUNWINDSTACK_DWARF_EH_FRAME_WITH_HDR_H

libunwindstack/DwarfEhFrame.cpp→libunwindstack/DwarfEhFrameWithHdr.cpp

+12 −12
Original line number Diff line number Diff line
@@ -20,13 +20,13 @@ 
#include <unwindstack/Memory.h>



#include "Check.h"

#include "DwarfEhFrame.h"

#include "DwarfEhFrameWithHdr.h"

#include "DwarfError.h"



namespace unwindstack {



template <typename AddressType>

bool DwarfEhFrame<AddressType>::Init(uint64_t offset, uint64_t size) {

bool DwarfEhFrameWithHdr<AddressType>::Init(uint64_t offset, uint64_t size) {

  uint8_t data[4];



  memory_.clear_func_offset();
@@ -73,7 +73,7 @@ bool DwarfEhFrame<AddressType>::Init(uint64_t offset, uint64_t size) { 
}



template <typename AddressType>

const DwarfFde* DwarfEhFrame<AddressType>::GetFdeFromIndex(size_t index) {

const DwarfFde* DwarfEhFrameWithHdr<AddressType>::GetFdeFromIndex(size_t index) {

  const FdeInfo* info = GetFdeInfoFromIndex(index);

  if (info == nullptr) {

    return nullptr;
@@ -82,8 +82,8 @@ const DwarfFde* DwarfEhFrame<AddressType>::GetFdeFromIndex(size_t index) { 
}



template <typename AddressType>

const typename DwarfEhFrame<AddressType>::FdeInfo* DwarfEhFrame<AddressType>::GetFdeInfoFromIndex(

    size_t index) {

const typename DwarfEhFrameWithHdr<AddressType>::FdeInfo*

DwarfEhFrameWithHdr<AddressType>::GetFdeInfoFromIndex(size_t index) {

  auto entry = fde_info_.find(index);

  if (entry != fde_info_.end()) {

    return &fde_info_[index];
@@ -105,7 +105,7 @@ const typename DwarfEhFrame<AddressType>::FdeInfo* DwarfEhFrame<AddressType>::Ge 
}



template <typename AddressType>

bool DwarfEhFrame<AddressType>::GetFdeOffsetBinary(uint64_t pc, uint64_t* fde_offset,

bool DwarfEhFrameWithHdr<AddressType>::GetFdeOffsetBinary(uint64_t pc, uint64_t* fde_offset,

                                                          uint64_t total_entries) {

  CHECK(fde_count_ > 0);

  CHECK(total_entries <= fde_count_);
@@ -134,7 +134,7 @@ bool DwarfEhFrame<AddressType>::GetFdeOffsetBinary(uint64_t pc, uint64_t* fde_of 
}



template <typename AddressType>

bool DwarfEhFrame<AddressType>::GetFdeOffsetSequential(uint64_t pc, uint64_t* fde_offset) {

bool DwarfEhFrameWithHdr<AddressType>::GetFdeOffsetSequential(uint64_t pc, uint64_t* fde_offset) {

  CHECK(fde_count_ != 0);

  last_error_ = DWARF_ERROR_NONE;

  // We can do a binary search if the pc is in the range of the elements
@@ -196,7 +196,7 @@ bool DwarfEhFrame<AddressType>::GetFdeOffsetSequential(uint64_t pc, uint64_t* fd 
}



template <typename AddressType>

bool DwarfEhFrame<AddressType>::GetFdeOffsetFromPc(uint64_t pc, uint64_t* fde_offset) {

bool DwarfEhFrameWithHdr<AddressType>::GetFdeOffsetFromPc(uint64_t pc, uint64_t* fde_offset) {

  if (fde_count_ == 0) {

    return false;

  }
@@ -210,8 +210,8 @@ bool DwarfEhFrame<AddressType>::GetFdeOffsetFromPc(uint64_t pc, uint64_t* fde_of 
  }

}



// Explicitly instantiate DwarfEhFrame.

template class DwarfEhFrame<uint32_t>;

template class DwarfEhFrame<uint64_t>;

// Explicitly instantiate DwarfEhFrameWithHdr

template class DwarfEhFrameWithHdr<uint32_t>;

template class DwarfEhFrameWithHdr<uint64_t>;



}  // namespace unwindstack