patchoat.h revision 6eb6a39bdcf669655190d40d20f8d2e663b262f4 
1/*
2 * Copyright (C) 2014 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#ifndef ART_PATCHOAT_PATCHOAT_H_
18#define ART_PATCHOAT_PATCHOAT_H_
19
20#include "arch/instruction_set.h"
21#include "base/macros.h"
22#include "base/mutex.h"
23#include "elf_file.h"
24#include "elf_utils.h"
25#include "gc/accounting/space_bitmap.h"
26#include "gc/space/image_space.h"
27#include "gc/heap.h"
28#include "os.h"
29#include "runtime.h"
30
31namespace art {
32
33class ArtMethod;
34class ImageHeader;
35class OatHeader;
36
37namespace mirror {
38class Object;
39class PointerArray;
40class Reference;
41class Class;
42}  // namespace mirror
43
44class PatchOat {
45 public:
46  // Patch only the oat file
47  static bool Patch(File* oat_in, off_t delta, File* oat_out, TimingLogger* timings,
48                    bool output_oat_opened_from_fd,  // Was this using --oatput-oat-fd ?
49                    bool new_oat_out);               // Output oat was a new file created by us?
50
51  // Patch only the image (art file)
52  static bool Patch(const std::string& art_location, off_t delta, File* art_out, InstructionSet isa,
53                    TimingLogger* timings);
54
55  // Patch both the image and the oat file
56  static bool Patch(const std::string& art_location,
57                    off_t delta,
58                    const std::string& output_directory,
59                    InstructionSet isa,
60                    TimingLogger* timings);
61
62  ~PatchOat() {}
63  PatchOat(PatchOat&&) = default;
64
65 private:
66  // Takes ownership only of the ElfFile. All other pointers are only borrowed.
67  PatchOat(ElfFile* oat_file, off_t delta, TimingLogger* timings)
68      : oat_file_(oat_file), image_(nullptr), bitmap_(nullptr), heap_(nullptr), delta_(delta),
69        isa_(kNone), space_map_(nullptr), timings_(timings) {}
70  PatchOat(InstructionSet isa, MemMap* image, gc::accounting::ContinuousSpaceBitmap* bitmap,
71           MemMap* heap, off_t delta, TimingLogger* timings)
72      : image_(image), bitmap_(bitmap), heap_(heap),
73        delta_(delta), isa_(isa), space_map_(nullptr), timings_(timings) {}
74  PatchOat(InstructionSet isa, ElfFile* oat_file, MemMap* image,
75           gc::accounting::ContinuousSpaceBitmap* bitmap, MemMap* heap, off_t delta,
76           std::map<gc::space::ImageSpace*, std::unique_ptr<MemMap>>* map, TimingLogger* timings)
77      : oat_file_(oat_file), image_(image), bitmap_(bitmap), heap_(heap),
78        delta_(delta), isa_(isa), space_map_(map), timings_(timings) {}
79
80  // Was the .art image at image_path made with --compile-pic ?
81  static bool IsImagePic(const ImageHeader& image_header, const std::string& image_path);
82
83  enum MaybePic {
84      NOT_PIC,            // Code not pic. Patch as usual.
85      PIC,                // Code was pic. Create symlink; skip OAT patching.
86      ERROR_OAT_FILE,     // Failed to symlink oat file
87      ERROR_FIRST = ERROR_OAT_FILE,
88  };
89
90  // Was the .oat image at oat_in made with --compile-pic ?
91  static MaybePic IsOatPic(const ElfFile* oat_in);
92
93  // Attempt to replace the file with a symlink
94  // Returns false if it fails
95  static bool ReplaceOatFileWithSymlink(const std::string& input_oat_filename,
96                                        const std::string& output_oat_filename,
97                                        bool output_oat_opened_from_fd,
98                                        bool new_oat_out);  // Output oat was newly created?
99
100  static void BitmapCallback(mirror::Object* obj, void* arg)
101      SHARED_REQUIRES(Locks::mutator_lock_) {
102    reinterpret_cast<PatchOat*>(arg)->VisitObject(obj);
103  }
104
105  void VisitObject(mirror::Object* obj)
106      SHARED_REQUIRES(Locks::mutator_lock_);
107  void FixupMethod(ArtMethod* object, ArtMethod* copy)
108      SHARED_REQUIRES(Locks::mutator_lock_);
109  bool InHeap(mirror::Object*);
110
111  // Patches oat in place, modifying the oat_file given to the constructor.
112  bool PatchElf();
113  template <typename ElfFileImpl>
114  bool PatchElf(ElfFileImpl* oat_file);
115  template <typename ElfFileImpl>
116  bool PatchOatHeader(ElfFileImpl* oat_file);
117
118  bool PatchImage(bool primary_image) SHARED_REQUIRES(Locks::mutator_lock_);
119  void PatchArtFields(const ImageHeader* image_header) SHARED_REQUIRES(Locks::mutator_lock_);
120  void PatchArtMethods(const ImageHeader* image_header) SHARED_REQUIRES(Locks::mutator_lock_);
121  void PatchInternedStrings(const ImageHeader* image_header)
122      SHARED_REQUIRES(Locks::mutator_lock_);
123  void PatchClassTable(const ImageHeader* image_header)
124      SHARED_REQUIRES(Locks::mutator_lock_);
125  void PatchDexFileArrays(mirror::ObjectArray<mirror::Object>* img_roots)
126      SHARED_REQUIRES(Locks::mutator_lock_);
127
128  bool WriteElf(File* out);
129  bool WriteImage(File* out);
130
131  template <typename T>
132  T* RelocatedCopyOf(T* obj) const {
133    if (obj == nullptr) {
134      return nullptr;
135    }
136    DCHECK_GT(reinterpret_cast<uintptr_t>(obj), reinterpret_cast<uintptr_t>(heap_->Begin()));
137    DCHECK_LT(reinterpret_cast<uintptr_t>(obj), reinterpret_cast<uintptr_t>(heap_->End()));
138    uintptr_t heap_off =
139        reinterpret_cast<uintptr_t>(obj) - reinterpret_cast<uintptr_t>(heap_->Begin());
140    DCHECK_LT(heap_off, image_->Size());
141    return reinterpret_cast<T*>(image_->Begin() + heap_off);
142  }
143
144  template <typename T>
145  T* RelocatedCopyOfFollowImages(T* obj) const {
146    if (obj == nullptr) {
147      return nullptr;
148    }
149    // Find ImageSpace this belongs to.
150    auto image_spaces = Runtime::Current()->GetHeap()->GetBootImageSpaces();
151    for (gc::space::ImageSpace* image_space : image_spaces) {
152      if (image_space->Contains(obj)) {
153        uintptr_t heap_off = reinterpret_cast<uintptr_t>(obj) -
154                             reinterpret_cast<uintptr_t>(image_space->GetMemMap()->Begin());
155        return reinterpret_cast<T*>(space_map_->find(image_space)->second->Begin() + heap_off);
156      }
157    }
158    LOG(FATAL) << "Did not find object in boot image space " << obj;
159    UNREACHABLE();
160  }
161
162  template <typename T>
163  T* RelocatedAddressOfPointer(T* obj) const {
164    if (obj == nullptr) {
165      return obj;
166    }
167    auto ret = reinterpret_cast<uintptr_t>(obj) + delta_;
168    // Trim off high bits in case negative relocation with 64 bit patchoat.
169    if (InstructionSetPointerSize(isa_) == sizeof(uint32_t)) {
170      ret = static_cast<uintptr_t>(static_cast<uint32_t>(ret));
171    }
172    return reinterpret_cast<T*>(ret);
173  }
174
175  template <typename T>
176  T RelocatedAddressOfIntPointer(T obj) const {
177    if (obj == 0) {
178      return obj;
179    }
180    T ret = obj + delta_;
181    // Trim off high bits in case negative relocation with 64 bit patchoat.
182    if (InstructionSetPointerSize(isa_) == 4) {
183      ret = static_cast<T>(static_cast<uint32_t>(ret));
184    }
185    return ret;
186  }
187
188  // Walks through the old image and patches the mmap'd copy of it to the new offset. It does not
189  // change the heap.
190  class PatchVisitor {
191  public:
192    PatchVisitor(PatchOat* patcher, mirror::Object* copy) : patcher_(patcher), copy_(copy) {}
193    ~PatchVisitor() {}
194    void operator() (mirror::Object* obj, MemberOffset off, bool b) const
195        REQUIRES(Locks::mutator_lock_, Locks::heap_bitmap_lock_);
196    // For reference classes.
197    void operator() (mirror::Class* cls, mirror::Reference* ref) const
198        REQUIRES(Locks::mutator_lock_, Locks::heap_bitmap_lock_);
199    // TODO: Consider using these for updating native class roots?
200    void VisitRootIfNonNull(mirror::CompressedReference<mirror::Object>* root ATTRIBUTE_UNUSED)
201        const {}
202    void VisitRoot(mirror::CompressedReference<mirror::Object>* root ATTRIBUTE_UNUSED) const {}
203
204  private:
205    PatchOat* const patcher_;
206    mirror::Object* const copy_;
207  };
208
209  // The elf file we are patching.
210  std::unique_ptr<ElfFile> oat_file_;
211  // A mmap of the image we are patching. This is modified.
212  const MemMap* const image_;
213  // The bitmap over the image within the heap we are patching. This is not modified.
214  gc::accounting::ContinuousSpaceBitmap* const bitmap_;
215  // The heap we are patching. This is not modified.
216  const MemMap* const heap_;
217  // The amount we are changing the offset by.
218  const off_t delta_;
219  // Active instruction set, used to know the entrypoint size.
220  const InstructionSet isa_;
221
222  const std::map<gc::space::ImageSpace*, std::unique_ptr<MemMap>>* space_map_;
223
224  TimingLogger* timings_;
225
226  friend class FixupRootVisitor;
227  friend class RelocatedPointerVisitor;
228  friend class PatchOatArtFieldVisitor;
229  friend class PatchOatArtMethodVisitor;
230  DISALLOW_IMPLICIT_CONSTRUCTORS(PatchOat);
231};
232
233}  // namespace art
234#endif  // ART_PATCHOAT_PATCHOAT_H_
235