libunwindstack/DwarfDebugFrame.cpp - android_system_core - Gitiles

 /*
  * 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 "DwarfDebugFrame.h"
 #include "DwarfMemory.h"
 #include "DwarfSection.h"
 #include "DwarfStructs.h"
 #include "Memory.h"

 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>;
	/*
	* 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 "DwarfDebugFrame.h"
	#include "DwarfMemory.h"
	#include "DwarfSection.h"
	#include "DwarfStructs.h"
	#include "Memory.h"

	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>;