/*
 * Copyright (C) 2011 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 "oat.h"

#include <string.h>

#include "android-base/stringprintf.h"

#include "arch/instruction_set.h"
#include "arch/instruction_set_features.h"
#include "base/bit_utils.h"
#include "base/strlcpy.h"

namespace art {

using android::base::StringPrintf;

constexpr uint8_t OatHeader::kOatMagic[4];
constexpr uint8_t OatHeader::kOatVersion[4];
constexpr const char OatHeader::kTrueValue[];
constexpr const char OatHeader::kFalseValue[];

static size_t ComputeOatHeaderSize(const SafeMap<std::string, std::string>* variable_data) {
  size_t estimate = 0U;
  if (variable_data != nullptr) {
    SafeMap<std::string, std::string>::const_iterator it = variable_data->begin();
    SafeMap<std::string, std::string>::const_iterator end = variable_data->end();
    for ( ; it != end; ++it) {
      estimate += it->first.length() + 1;
      estimate += it->second.length() + 1;
    }
  }
  return sizeof(OatHeader) + estimate;
}

OatHeader* OatHeader::Create(InstructionSet instruction_set,
                             const InstructionSetFeatures* instruction_set_features,
                             uint32_t dex_file_count,
                             const SafeMap<std::string, std::string>* variable_data) {
  // Estimate size of optional data.
  size_t needed_size = ComputeOatHeaderSize(variable_data);

  // Reserve enough memory.
  void* memory = operator new (needed_size);

  // Create the OatHeader in-place.
  return new (memory) OatHeader(instruction_set,
                                instruction_set_features,
                                dex_file_count,
                                variable_data);
}

OatHeader::OatHeader(InstructionSet instruction_set,
                     const InstructionSetFeatures* instruction_set_features,
                     uint32_t dex_file_count,
                     const SafeMap<std::string, std::string>* variable_data)
    : oat_checksum_(0u),
      instruction_set_(instruction_set),
      instruction_set_features_bitmap_(instruction_set_features->AsBitmap()),
      dex_file_count_(dex_file_count),
      oat_dex_files_offset_(0),
      executable_offset_(0),
      jni_dlsym_lookup_offset_(0),
      quick_generic_jni_trampoline_offset_(0),
      quick_imt_conflict_trampoline_offset_(0),
      quick_resolution_trampoline_offset_(0),
      quick_to_interpreter_bridge_offset_(0) {
  // Don't want asserts in header as they would be checked in each file that includes it. But the
  // fields are private, so we check inside a method.
  static_assert(sizeof(magic_) == sizeof(kOatMagic),
                "Oat magic and magic_ have different lengths.");
  static_assert(sizeof(version_) == sizeof(kOatVersion),
                "Oat version and version_ have different lengths.");

  memcpy(magic_, kOatMagic, sizeof(kOatMagic));
  memcpy(version_, kOatVersion, sizeof(kOatVersion));

  CHECK_NE(instruction_set, InstructionSet::kNone);

  // Flatten the map. Will also update variable_size_data_size_.
  Flatten(variable_data);
}

bool OatHeader::IsValid() const {
  if (memcmp(magic_, kOatMagic, sizeof(kOatMagic)) != 0) {
    return false;
  }
  if (memcmp(version_, kOatVersion, sizeof(kOatVersion)) != 0) {
    return false;
  }
  if (!IsAligned<kPageSize>(executable_offset_)) {
    return false;
  }
  if (!IsValidInstructionSet(instruction_set_)) {
    return false;
  }
  return true;
}

std::string OatHeader::GetValidationErrorMessage() const {
  if (memcmp(magic_, kOatMagic, sizeof(kOatMagic)) != 0) {
    static_assert(sizeof(kOatMagic) == 4, "kOatMagic has unexpected length");
    return StringPrintf("Invalid oat magic, expected 0x%x%x%x%x, got 0x%x%x%x%x.",
                        kOatMagic[0], kOatMagic[1], kOatMagic[2], kOatMagic[3],
                        magic_[0], magic_[1], magic_[2], magic_[3]);
  }
  if (memcmp(version_, kOatVersion, sizeof(kOatVersion)) != 0) {
    static_assert(sizeof(kOatVersion) == 4, "kOatVersion has unexpected length");
    return StringPrintf("Invalid oat version, expected 0x%x%x%x%x, got 0x%x%x%x%x.",
                        kOatVersion[0], kOatVersion[1], kOatVersion[2], kOatVersion[3],
                        version_[0], version_[1], version_[2], version_[3]);
  }
  if (!IsAligned<kPageSize>(executable_offset_)) {
    return "Executable offset not page-aligned.";
  }
  if (!IsValidInstructionSet(instruction_set_)) {
    return StringPrintf("Invalid instruction set, %d.", static_cast<int>(instruction_set_));
  }
  return "";
}

const char* OatHeader::GetMagic() const {
  CHECK(IsValid());
  return reinterpret_cast<const char*>(magic_);
}

uint32_t OatHeader::GetChecksum() const {
  CHECK(IsValid());
  return oat_checksum_;
}

void OatHeader::SetChecksum(uint32_t oat_checksum) {
  oat_checksum_ = oat_checksum;
}

InstructionSet OatHeader::GetInstructionSet() const {
  CHECK(IsValid());
  return instruction_set_;
}

uint32_t OatHeader::GetInstructionSetFeaturesBitmap() const {
  CHECK(IsValid());
  return instruction_set_features_bitmap_;
}

uint32_t OatHeader::GetOatDexFilesOffset() const {
  DCHECK(IsValid());
  DCHECK_GT(oat_dex_files_offset_, sizeof(OatHeader));
  return oat_dex_files_offset_;
}

void OatHeader::SetOatDexFilesOffset(uint32_t oat_dex_files_offset) {
  DCHECK_GT(oat_dex_files_offset, sizeof(OatHeader));
  DCHECK(IsValid());
  DCHECK_EQ(oat_dex_files_offset_, 0u);

  oat_dex_files_offset_ = oat_dex_files_offset;
}

uint32_t OatHeader::GetExecutableOffset() const {
  DCHECK(IsValid());
  DCHECK_ALIGNED(executable_offset_, kPageSize);
  CHECK_GT(executable_offset_, sizeof(OatHeader));
  return executable_offset_;
}

void OatHeader::SetExecutableOffset(uint32_t executable_offset) {
  DCHECK_ALIGNED(executable_offset, kPageSize);
  CHECK_GT(executable_offset, sizeof(OatHeader));
  DCHECK(IsValid());
  DCHECK_EQ(executable_offset_, 0U);

  executable_offset_ = executable_offset;
}

static const void* GetTrampoline(const OatHeader& header, uint32_t offset) {
  return (offset != 0u) ? reinterpret_cast<const uint8_t*>(&header) + offset : nullptr;
}

const void* OatHeader::GetJniDlsymLookup() const {
  return GetTrampoline(*this, GetJniDlsymLookupOffset());
}

uint32_t OatHeader::GetJniDlsymLookupOffset() const {
  DCHECK(IsValid());
  return jni_dlsym_lookup_offset_;
}

void OatHeader::SetJniDlsymLookupOffset(uint32_t offset) {
  DCHECK(IsValid());
  DCHECK_EQ(jni_dlsym_lookup_offset_, 0U) << offset;

  jni_dlsym_lookup_offset_ = offset;
}

const void* OatHeader::GetQuickGenericJniTrampoline() const {
  return GetTrampoline(*this, GetQuickGenericJniTrampolineOffset());
}

uint32_t OatHeader::GetQuickGenericJniTrampolineOffset() const {
  DCHECK(IsValid());
  CHECK_GE(quick_generic_jni_trampoline_offset_, jni_dlsym_lookup_offset_);
  return quick_generic_jni_trampoline_offset_;
}

void OatHeader::SetQuickGenericJniTrampolineOffset(uint32_t offset) {
  CHECK(offset == 0 || offset >= jni_dlsym_lookup_offset_);
  DCHECK(IsValid());
  DCHECK_EQ(quick_generic_jni_trampoline_offset_, 0U) << offset;

  quick_generic_jni_trampoline_offset_ = offset;
}

const void* OatHeader::GetQuickImtConflictTrampoline() const {
  return GetTrampoline(*this, GetQuickImtConflictTrampolineOffset());
}

uint32_t OatHeader::GetQuickImtConflictTrampolineOffset() const {
  DCHECK(IsValid());
  CHECK_GE(quick_imt_conflict_trampoline_offset_, quick_generic_jni_trampoline_offset_);
  return quick_imt_conflict_trampoline_offset_;
}

void OatHeader::SetQuickImtConflictTrampolineOffset(uint32_t offset) {
  CHECK(offset == 0 || offset >= quick_generic_jni_trampoline_offset_);
  DCHECK(IsValid());
  DCHECK_EQ(quick_imt_conflict_trampoline_offset_, 0U) << offset;

  quick_imt_conflict_trampoline_offset_ = offset;
}

const void* OatHeader::GetQuickResolutionTrampoline() const {
  return GetTrampoline(*this, GetQuickResolutionTrampolineOffset());
}

uint32_t OatHeader::GetQuickResolutionTrampolineOffset() const {
  DCHECK(IsValid());
  CHECK_GE(quick_resolution_trampoline_offset_, quick_imt_conflict_trampoline_offset_);
  return quick_resolution_trampoline_offset_;
}

void OatHeader::SetQuickResolutionTrampolineOffset(uint32_t offset) {
  CHECK(offset == 0 || offset >= quick_imt_conflict_trampoline_offset_);
  DCHECK(IsValid());
  DCHECK_EQ(quick_resolution_trampoline_offset_, 0U) << offset;

  quick_resolution_trampoline_offset_ = offset;
}

const void* OatHeader::GetQuickToInterpreterBridge() const {
  return GetTrampoline(*this, GetQuickToInterpreterBridgeOffset());
}

uint32_t OatHeader::GetQuickToInterpreterBridgeOffset() const {
  DCHECK(IsValid());
  CHECK_GE(quick_to_interpreter_bridge_offset_, quick_resolution_trampoline_offset_);
  return quick_to_interpreter_bridge_offset_;
}

void OatHeader::SetQuickToInterpreterBridgeOffset(uint32_t offset) {
  CHECK(offset == 0 || offset >= quick_resolution_trampoline_offset_);
  DCHECK(IsValid());
  DCHECK_EQ(quick_to_interpreter_bridge_offset_, 0U) << offset;

  quick_to_interpreter_bridge_offset_ = offset;
}

uint32_t OatHeader::GetKeyValueStoreSize() const {
  CHECK(IsValid());
  return key_value_store_size_;
}

const uint8_t* OatHeader::GetKeyValueStore() const {
  CHECK(IsValid());
  return key_value_store_;
}

// Advance start until it is either end or \0.
static const char* ParseString(const char* start, const char* end) {
  while (start < end && *start != 0) {
    start++;
  }
  return start;
}

const char* OatHeader::GetStoreValueByKey(const char* key) const {
  const char* ptr = reinterpret_cast<const char*>(&key_value_store_);
  const char* end = ptr + key_value_store_size_;

  while (ptr < end) {
    // Scan for a closing zero.
    const char* str_end = ParseString(ptr, end);
    if (str_end < end) {
      if (strcmp(key, ptr) == 0) {
        // Same as key. Check if value is OK.
        if (ParseString(str_end + 1, end) < end) {
          return str_end + 1;
        }
      } else {
        // Different from key. Advance over the value.
        ptr = ParseString(str_end + 1, end) + 1;
      }
    } else {
      break;
    }
  }
  // Not found.
  return nullptr;
}

bool OatHeader::GetStoreKeyValuePairByIndex(size_t index, const char** key,
                                            const char** value) const {
  const char* ptr = reinterpret_cast<const char*>(&key_value_store_);
  const char* end = ptr + key_value_store_size_;
  ssize_t counter = static_cast<ssize_t>(index);

  while (ptr < end && counter >= 0) {
    // Scan for a closing zero.
    const char* str_end = ParseString(ptr, end);
    if (str_end < end) {
      const char* maybe_key = ptr;
      ptr = ParseString(str_end + 1, end) + 1;
      if (ptr <= end) {
        if (counter == 0) {
          *key = maybe_key;
          *value = str_end + 1;
          return true;
        } else {
          counter--;
        }
      } else {
        return false;
      }
    } else {
      break;
    }
  }
  // Not found.
  return false;
}

size_t OatHeader::GetHeaderSize() const {
  return sizeof(OatHeader) + key_value_store_size_;
}

bool OatHeader::IsDebuggable() const {
  return IsKeyEnabled(OatHeader::kDebuggableKey);
}

bool OatHeader::IsConcurrentCopying() const {
  return IsKeyEnabled(OatHeader::kConcurrentCopying);
}

bool OatHeader::IsNativeDebuggable() const {
  return IsKeyEnabled(OatHeader::kNativeDebuggableKey);
}

CompilerFilter::Filter OatHeader::GetCompilerFilter() const {
  CompilerFilter::Filter filter;
  const char* key_value = GetStoreValueByKey(kCompilerFilter);
  CHECK(key_value != nullptr) << "compiler-filter not found in oat header";
  CHECK(CompilerFilter::ParseCompilerFilter(key_value, &filter))
      << "Invalid compiler-filter in oat header: " << key_value;
  return filter;
}

bool OatHeader::KeyHasValue(const char* key, const char* value, size_t value_size) const {
  const char* key_value = GetStoreValueByKey(key);
  return (key_value != nullptr && strncmp(key_value, value, value_size) == 0);
}

bool OatHeader::IsKeyEnabled(const char* key) const {
  return KeyHasValue(key, kTrueValue, sizeof(kTrueValue));
}

void OatHeader::Flatten(const SafeMap<std::string, std::string>* key_value_store) {
  char* data_ptr = reinterpret_cast<char*>(&key_value_store_);
  if (key_value_store != nullptr) {
    SafeMap<std::string, std::string>::const_iterator it = key_value_store->begin();
    SafeMap<std::string, std::string>::const_iterator end = key_value_store->end();
    for ( ; it != end; ++it) {
      strlcpy(data_ptr, it->first.c_str(), it->first.length() + 1);
      data_ptr += it->first.length() + 1;
      strlcpy(data_ptr, it->second.c_str(), it->second.length() + 1);
      data_ptr += it->second.length() + 1;
    }
  }
  key_value_store_size_ = data_ptr - reinterpret_cast<char*>(&key_value_store_);
}

OatMethodOffsets::OatMethodOffsets(uint32_t code_offset) : code_offset_(code_offset) {
}

OatMethodOffsets::~OatMethodOffsets() {}

}  // namespace art