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      1 /*
      2  * Copyright (C) 2015 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 SIMPLE_PERF_RECORD_FILE_H_
     18 #define SIMPLE_PERF_RECORD_FILE_H_
     19 
     20 #include <stdio.h>
     21 #include <memory>
     22 #include <string>
     23 #include <vector>
     24 
     25 #include <base/macros.h>
     26 
     27 #include "perf_event.h"
     28 #include "record.h"
     29 #include "record_file_format.h"
     30 
     31 class EventFd;
     32 
     33 // RecordFileWriter writes to a perf record file, like perf.data.
     34 class RecordFileWriter {
     35  public:
     36   static std::unique_ptr<RecordFileWriter> CreateInstance(
     37       const std::string& filename, const perf_event_attr& event_attr,
     38       const std::vector<std::unique_ptr<EventFd>>& event_fds);
     39 
     40   ~RecordFileWriter();
     41 
     42   bool WriteData(const void* buf, size_t len);
     43 
     44   bool WriteData(const std::vector<char>& data) {
     45     return WriteData(data.data(), data.size());
     46   }
     47 
     48   // Use MmapRecords and SampleRecords in record file to conclude which modules/files were executing
     49   // at sample times.
     50   bool GetHitModules(std::vector<std::string>* hit_kernel_modules,
     51                      std::vector<std::string>* hit_user_files);
     52 
     53   bool WriteFeatureHeader(size_t feature_count);
     54   bool WriteBuildIdFeature(const std::vector<BuildIdRecord>& build_id_records);
     55 
     56   // Normally, Close() should be called after writing. But if something
     57   // wrong happens and we need to finish in advance, the destructor
     58   // will take care of calling Close().
     59   bool Close();
     60 
     61  private:
     62   RecordFileWriter(const std::string& filename, FILE* fp);
     63   bool WriteAttrSection(const perf_event_attr& event_attr,
     64                         const std::vector<std::unique_ptr<EventFd>>& event_fds);
     65   void GetHitModulesInBuffer(const char* p, const char* end,
     66                              std::vector<std::string>* hit_kernel_modules,
     67                              std::vector<std::string>* hit_user_files);
     68   bool WriteFileHeader();
     69   bool Write(const void* buf, size_t len);
     70 
     71   const std::string filename_;
     72   FILE* record_fp_;
     73 
     74   perf_event_attr event_attr_;
     75   uint64_t attr_section_offset_;
     76   uint64_t attr_section_size_;
     77   uint64_t data_section_offset_;
     78   uint64_t data_section_size_;
     79 
     80   std::vector<int> features_;
     81   int feature_count_;
     82   int current_feature_index_;
     83 
     84   DISALLOW_COPY_AND_ASSIGN(RecordFileWriter);
     85 };
     86 
     87 // RecordFileReader read contents from a perf record file, like perf.data.
     88 class RecordFileReader {
     89  public:
     90   static std::unique_ptr<RecordFileReader> CreateInstance(const std::string& filename);
     91 
     92   ~RecordFileReader();
     93 
     94   const PerfFileFormat::FileHeader* FileHeader();
     95   std::vector<const PerfFileFormat::FileAttr*> AttrSection();
     96   std::vector<uint64_t> IdsForAttr(const PerfFileFormat::FileAttr* attr);
     97   std::vector<std::unique_ptr<const Record>> DataSection();
     98   std::vector<PerfFileFormat::SectionDesc> FeatureSectionDescriptors();
     99   const char* DataAtOffset(uint64_t offset) {
    100     return mmap_addr_ + offset;
    101   }
    102   bool Close();
    103 
    104  private:
    105   RecordFileReader(const std::string& filename, int fd);
    106   bool MmapFile();
    107 
    108   const std::string filename_;
    109   int record_fd_;
    110 
    111   const char* mmap_addr_;
    112   size_t mmap_len_;
    113 
    114   DISALLOW_COPY_AND_ASSIGN(RecordFileReader);
    115 };
    116 
    117 #endif  // SIMPLE_PERF_RECORD_FILE_H_
    118