openjdkjvmti/ti_redefine.h

/* Copyright (C) 2016 The Android Open Source Project
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This file implements interfaces from the file jvmti.h. This implementation
 * is licensed under the same terms as the file jvmti.h.  The
 * copyright and license information for the file jvmti.h follows.
 *
 * Copyright (c) 2003, 2011, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * under the terms of the GNU General Public License version 2 only, as
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 * particular file as subject to the "Classpath" exception as provided
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 * version 2 for more details (a copy is included in the LICENSE file that
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#ifndef ART_OPENJDKJVMTI_TI_REDEFINE_H_
#define ART_OPENJDKJVMTI_TI_REDEFINE_H_

#include <functional>
#include <string>

#include <jni.h>

#include "art_field.h"
#include "art_jvmti.h"
#include "base/array_ref.h"
#include "base/globals.h"
#include "dex/dex_file.h"
#include "dex/dex_file_structs.h"
#include "jni/jni_env_ext-inl.h"
#include "jvmti.h"
#include "mirror/array.h"
#include "mirror/class.h"
#include "mirror/dex_cache.h"
#include "obj_ptr.h"

namespace art {
namespace dex {
struct ClassDef;
}  // namespace dex
}  // namespace art

namespace openjdkjvmti {

class ArtClassDefinition;
class RedefinitionDataHolder;
class RedefinitionDataIter;

enum class RedefinitionType {
  kStructural,
  kNormal,
};

// Class that can redefine a single class's methods.
class Redefiner {
 public:
  // Redefine the given classes with the given dex data. Note this function does not take ownership
  // of the dex_data pointers. It is not used after this call however and may be freed if desired.
  // The caller is responsible for freeing it. The runtime makes its own copy of the data. This
  // function does not call the transformation events.
  static jvmtiError RedefineClassesDirect(ArtJvmTiEnv* env,
                                          art::Runtime* runtime,
                                          art::Thread* self,
                                          const std::vector<ArtClassDefinition>& definitions,
                                          RedefinitionType type,
                                          /*out*/std::string* error_msg);

  // Redefine the given classes with the given dex data. Note this function does not take ownership
  // of the dex_data pointers. It is not used after this call however and may be freed if desired.
  // The caller is responsible for freeing it. The runtime makes its own copy of the data.
  static jvmtiError RedefineClasses(jvmtiEnv* env,
                                    jint class_count,
                                    const jvmtiClassDefinition* definitions);

  static jvmtiError IsModifiableClass(jvmtiEnv* env, jclass klass, jboolean* is_redefinable);
  static jvmtiError IsStructurallyModifiableClass(jvmtiEnv* env,
                                                  jclass klass,
                                                  jboolean* is_redefinable);

  static art::MemMap MoveDataToMemMap(const std::string& original_location,
                                      art::ArrayRef<const unsigned char> data,
                                      std::string* error_msg);

  // Helper for checking if redefinition/retransformation is allowed.
  template<RedefinitionType kType = RedefinitionType::kNormal>
  static jvmtiError GetClassRedefinitionError(jclass klass, /*out*/std::string* error_msg)
      REQUIRES(!art::Locks::mutator_lock_);

  static jvmtiError StructurallyRedefineClassDirect(jvmtiEnv* env,
                                                    jclass klass,
                                                    const unsigned char* data,
                                                    jint data_size);

 private:
  class ClassRedefinition {
   public:
    ClassRedefinition(Redefiner* driver,
                      jclass klass,
                      const art::DexFile* redefined_dex_file,
                      const char* class_sig,
                      art::ArrayRef<const unsigned char> orig_dex_file)
      REQUIRES_SHARED(art::Locks::mutator_lock_);

    // NO_THREAD_SAFETY_ANALYSIS so we can unlock the class in the destructor.
    ~ClassRedefinition() NO_THREAD_SAFETY_ANALYSIS;

    // Move constructor so we can put these into a vector.
    ClassRedefinition(ClassRedefinition&& other)
        : driver_(other.driver_),
          klass_(other.klass_),
          dex_file_(std::move(other.dex_file_)),
          class_sig_(std::move(other.class_sig_)),
          original_dex_file_(other.original_dex_file_) {
      other.driver_ = nullptr;
    }

    art::ObjPtr<art::mirror::Class> GetMirrorClass() REQUIRES_SHARED(art::Locks::mutator_lock_);
    art::ObjPtr<art::mirror::ClassLoader> GetClassLoader()
        REQUIRES_SHARED(art::Locks::mutator_lock_);

    const art::DexFile& GetDexFile() {
      return *dex_file_;
    }

    art::mirror::DexCache* CreateNewDexCache(art::Handle<art::mirror::ClassLoader> loader)
        REQUIRES_SHARED(art::Locks::mutator_lock_);

    // This may return nullptr with a OOME pending if allocation fails.
    art::mirror::Object* AllocateOrGetOriginalDexFile()
        REQUIRES_SHARED(art::Locks::mutator_lock_);

    void RecordFailure(jvmtiError e, const std::string& err) {
      driver_->RecordFailure(e, class_sig_, err);
    }

    bool FinishRemainingAllocations(/*out*/RedefinitionDataIter* cur_data)
        REQUIRES_SHARED(art::Locks::mutator_lock_);

    bool AllocateAndRememberNewDexFileCookie(
        art::Handle<art::mirror::ClassLoader> source_class_loader,
        art::Handle<art::mirror::Object> dex_file_obj,
        /*out*/RedefinitionDataIter* cur_data)
          REQUIRES_SHARED(art::Locks::mutator_lock_);

    void FindAndAllocateObsoleteMethods(art::ObjPtr<art::mirror::Class> art_klass)
        REQUIRES(art::Locks::mutator_lock_);

    art::ObjPtr<art::mirror::Class> AllocateNewClassObject(art::Handle<art::mirror::DexCache> cache)
        REQUIRES_SHARED(art::Locks::mutator_lock_);

    uint32_t GetNewClassSize(bool with_embedded_tables, art::Handle<art::mirror::Class> old_class)
        REQUIRES_SHARED(art::Locks::mutator_lock_);

    // Checks that the dex file contains only the single expected class and that the top-level class
    // data has not been modified in an incompatible manner.
    bool CheckClass() REQUIRES_SHARED(art::Locks::mutator_lock_);

    // Checks that the contained class can be successfully verified.
    bool CheckVerification(const RedefinitionDataIter& holder)
        REQUIRES_SHARED(art::Locks::mutator_lock_);

    // Preallocates all needed allocations in klass so that we can pause execution safely.
    bool EnsureClassAllocationsFinished(/*out*/RedefinitionDataIter* data)
        REQUIRES_SHARED(art::Locks::mutator_lock_);

    // This will check that no constraints are violated (more than 1 class in dex file, any changes
    // in number/declaration of methods & fields, changes in access flags, etc.)
    bool CheckRedefinitionIsValid() REQUIRES_SHARED(art::Locks::mutator_lock_);

    // Checks that the class can even be redefined.
    bool CheckRedefinable() REQUIRES_SHARED(art::Locks::mutator_lock_);

    // Checks that the dex file does not add/remove methods, or change their modifiers or types in
    // illegal ways.
    bool CheckMethods() REQUIRES_SHARED(art::Locks::mutator_lock_);

    // Checks that the dex file does not modify fields types or modifiers in illegal ways.
    bool CheckFields() REQUIRES_SHARED(art::Locks::mutator_lock_);

    // Temporary check that a class undergoing structural redefinition has no instances. This
    // requirement will be removed in time.
    void UpdateJavaDexFile(art::ObjPtr<art::mirror::Object> java_dex_file,
                           art::ObjPtr<art::mirror::LongArray> new_cookie)
        REQUIRES(art::Locks::mutator_lock_);

    void UpdateFields(art::ObjPtr<art::mirror::Class> mclass)
        REQUIRES(art::Locks::mutator_lock_);

    void UpdateMethods(art::ObjPtr<art::mirror::Class> mclass,
                       const art::dex::ClassDef& class_def)
        REQUIRES(art::Locks::mutator_lock_);

    void UpdateClass(const RedefinitionDataIter& cur_data)
        REQUIRES(art::Locks::mutator_lock_);

    void ReverifyClass(const RedefinitionDataIter& cur_data)
        REQUIRES(art::Locks::mutator_lock_);

    void CollectNewFieldAndMethodMappings(const RedefinitionDataIter& data,
                                          std::map<art::ArtMethod*, art::ArtMethod*>* method_map,
                                          std::map<art::ArtField*, art::ArtField*>* field_map)
        REQUIRES(art::Locks::mutator_lock_);

    void RestoreObsoleteMethodMapsIfUnneeded(const RedefinitionDataIter* cur_data)
        REQUIRES(art::Locks::mutator_lock_);

    void ReleaseDexFile() REQUIRES_SHARED(art::Locks::mutator_lock_);

    void UnregisterBreakpoints() REQUIRES_SHARED(art::Locks::mutator_lock_);
    // This should be done with all threads suspended.
    void UnregisterJvmtiBreakpoints() REQUIRES_SHARED(art::Locks::mutator_lock_);

    void RecordNewMethodAdded();
    void RecordNewFieldAdded();

   private:
    bool IsStructuralRedefinition() const {
      DCHECK(!(added_fields_ || added_methods_) || driver_->IsStructuralRedefinition())
          << "added_fields_: " << added_fields_ << " added_methods_: " << added_methods_
          << " driver_->IsStructuralRedefinition(): " << driver_->IsStructuralRedefinition();
      return driver_->IsStructuralRedefinition() && (added_fields_ || added_methods_);
    }

    void UpdateClassStructurally(const RedefinitionDataIter& cur_data)
        REQUIRES(art::Locks::mutator_lock_);

    void UpdateClassInPlace(const RedefinitionDataIter& cur_data)
        REQUIRES(art::Locks::mutator_lock_);

    Redefiner* driver_;
    jclass klass_;
    std::unique_ptr<const art::DexFile> dex_file_;
    std::string class_sig_;
    art::ArrayRef<const unsigned char> original_dex_file_;

    bool added_fields_ = false;
    bool added_methods_ = false;

    // Does the class need to be reverified due to verification soft-fails possibly forcing
    // interpreter or lock-counting?
    bool needs_reverify_ = false;
  };

  ArtJvmTiEnv* env_;
  jvmtiError result_;
  art::Runtime* runtime_;
  art::Thread* self_;
  RedefinitionType type_;
  std::vector<ClassRedefinition> redefinitions_;
  // Kept as a jclass since we have weird run-state changes that make keeping it around as a
  // mirror::Class difficult and confusing.
  std::string* error_msg_;

  Redefiner(ArtJvmTiEnv* env,
            art::Runtime* runtime,
            art::Thread* self,
            RedefinitionType type,
            std::string* error_msg)
      : env_(env),
        result_(ERR(INTERNAL)),
        runtime_(runtime),
        self_(self),
        type_(type),
        redefinitions_(),
        error_msg_(error_msg) { }

  jvmtiError AddRedefinition(ArtJvmTiEnv* env, const ArtClassDefinition& def)
      REQUIRES_SHARED(art::Locks::mutator_lock_);

  template<RedefinitionType kType = RedefinitionType::kNormal>
  static jvmtiError IsModifiableClassGeneric(jvmtiEnv* env, jclass klass, jboolean* is_redefinable);

  template<RedefinitionType kType = RedefinitionType::kNormal>
  static jvmtiError GetClassRedefinitionError(art::Handle<art::mirror::Class> klass,
                                              /*out*/std::string* error_msg)
      REQUIRES_SHARED(art::Locks::mutator_lock_);

  jvmtiError Run() REQUIRES_SHARED(art::Locks::mutator_lock_);

  bool CheckAllRedefinitionAreValid() REQUIRES_SHARED(art::Locks::mutator_lock_);
  bool CheckAllClassesAreVerified(RedefinitionDataHolder& holder)
      REQUIRES_SHARED(art::Locks::mutator_lock_);
  bool EnsureAllClassAllocationsFinished(RedefinitionDataHolder& holder)
      REQUIRES_SHARED(art::Locks::mutator_lock_);
  bool FinishAllRemainingAllocations(RedefinitionDataHolder& holder)
      REQUIRES_SHARED(art::Locks::mutator_lock_);
  void ReleaseAllDexFiles() REQUIRES_SHARED(art::Locks::mutator_lock_);
  void ReverifyClasses(RedefinitionDataHolder& holder) REQUIRES(art::Locks::mutator_lock_);
  void UnregisterAllBreakpoints() REQUIRES_SHARED(art::Locks::mutator_lock_);
  // Restores the old obsolete methods maps if it turns out they weren't needed (ie there were no
  // new obsolete methods).
  void RestoreObsoleteMethodMapsIfUnneeded(RedefinitionDataHolder& holder)
      REQUIRES(art::Locks::mutator_lock_);

  bool IsStructuralRedefinition() const {
    return type_ == RedefinitionType::kStructural;
  }

  void RecordFailure(jvmtiError result, const std::string& class_sig, const std::string& error_msg);
  void RecordFailure(jvmtiError result, const std::string& error_msg) {
    RecordFailure(result, "NO CLASS", error_msg);
  }

  friend struct CallbackCtx;
  friend class RedefinitionDataHolder;
  friend class RedefinitionDataIter;
};

}  // namespace openjdkjvmti

#endif  // ART_OPENJDKJVMTI_TI_REDEFINE_H_