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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_READ_ELF_H_
     18 #define SIMPLE_PERF_READ_ELF_H_
     19 
     20 #include <functional>
     21 #include <ostream>
     22 #include <string>
     23 #include "build_id.h"
     24 
     25 // Read ELF functions are called in different situations, so it is hard to
     26 // decide whether to report error or not. So read ELF functions don't report
     27 // error when something wrong happens, instead they return ElfStatus, which
     28 // identifies different errors met while reading elf file.
     29 enum ElfStatus {
     30   NO_ERROR,
     31   FILE_NOT_FOUND,
     32   READ_FAILED,
     33   FILE_MALFORMED,
     34   NO_SYMBOL_TABLE,
     35   NO_BUILD_ID,
     36   BUILD_ID_MISMATCH,
     37   SECTION_NOT_FOUND,
     38 };
     39 
     40 std::ostream& operator<<(std::ostream& os, const ElfStatus& status);
     41 
     42 ElfStatus GetBuildIdFromNoteFile(const std::string& filename, BuildId* build_id);
     43 ElfStatus GetBuildIdFromElfFile(const std::string& filename, BuildId* build_id);
     44 ElfStatus GetBuildIdFromEmbeddedElfFile(const std::string& filename, uint64_t file_offset,
     45                                         uint32_t file_size, BuildId* build_id);
     46 
     47 // The symbol prefix used to indicate that the symbol belongs to android linker.
     48 static const std::string linker_prefix = "__dl_";
     49 
     50 struct ElfFileSymbol {
     51   uint64_t vaddr;
     52   uint64_t len;
     53   bool is_func;
     54   bool is_label;
     55   bool is_in_text_section;
     56   std::string name;
     57 
     58   ElfFileSymbol() : vaddr(0), len(0), is_func(false), is_label(false), is_in_text_section(false) {
     59   }
     60 };
     61 
     62 ElfStatus ParseSymbolsFromElfFile(const std::string& filename,
     63                                   const BuildId& expected_build_id,
     64                                   const std::function<void(const ElfFileSymbol&)>& callback);
     65 ElfStatus ParseSymbolsFromEmbeddedElfFile(const std::string& filename, uint64_t file_offset,
     66                                           uint32_t file_size, const BuildId& expected_build_id,
     67                                           const std::function<void(const ElfFileSymbol&)>& callback);
     68 
     69 ElfStatus ReadMinExecutableVirtualAddressFromElfFile(const std::string& filename,
     70                                                      const BuildId& expected_build_id,
     71                                                      uint64_t* min_addr);
     72 
     73 ElfStatus ReadSectionFromElfFile(const std::string& filename, const std::string& section_name,
     74                                  std::string* content);
     75 
     76 // Expose the following functions for unit tests.
     77 bool IsArmMappingSymbol(const char* name);
     78 ElfStatus IsValidElfFile(int fd);
     79 ElfStatus IsValidElfPath(const std::string& filename);
     80 bool GetBuildIdFromNoteSection(const char* section, size_t section_size, BuildId* build_id);
     81 
     82 #endif  // SIMPLE_PERF_READ_ELF_H_
     83