Source/cmELF.h

   1 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
   2    file Copyright.txt or https://cmake.org/licensing for details.  */
   3 #pragma once
   4
   5 #include "cmConfigure.h" // IWYU pragma: keep
   6
   7 #include <cstdint>
   8 #include <iosfwd>
   9 #include <memory>
  10 #include <string>
  11 #include <utility>
  12 #include <vector>
  13
  14 class cmELFInternal;
  15
  16 /** \class cmELF
  17  * \brief Executable and Link Format (ELF) parser.
  18  */
  19 class cmELF
  20 {
  21 public:
  22   /** Construct with the name of the ELF input file to parse.  */
  23   cmELF(const char* fname);
  24
  25   /** Destruct.   */
  26   ~cmELF();
  27
  28   cmELF(const cmELF&) = delete;
  29   cmELF& operator=(const cmELF&) = delete;
  30
  31   /** Get the error message if any.  */
  32   std::string const& GetErrorMessage() const { return this->ErrorMessage; }
  33
  34   /** Boolean conversion.  True if the ELF file is valid.  */
  35   explicit operator bool() const { return this->Valid(); }
  36
  37   /** Enumeration of ELF file types.  */
  38   enum FileType
  39   {
  40     FileTypeInvalid,
  41     FileTypeRelocatableObject,
  42     FileTypeExecutable,
  43     FileTypeSharedLibrary,
  44     FileTypeCore,
  45     FileTypeSpecificOS,
  46     FileTypeSpecificProc
  47   };
  48
  49   /** Represent string table entries.  */
  50   struct StringEntry
  51   {
  52     // The string value itself.
  53     std::string Value;
  54
  55     // The position in the file at which the string appears.
  56     unsigned long Position;
  57
  58     // The size of the string table entry.  This includes the space
  59     // allocated for one or more null terminators.
  60     unsigned long Size;
  61
  62     // The index of the section entry referencing the string.
  63     int IndexInSection;
  64   };
  65
  66   /** Represent entire dynamic section header */
  67   using DynamicEntryList = std::vector<std::pair<long, unsigned long>>;
  68
  69   /** Get the type of the file opened.  */
  70   FileType GetFileType() const;
  71
  72   /** Get the machine of the file opened.  */
  73   std::uint16_t GetMachine() const;
  74
  75   /** Get the number of ELF sections present.  */
  76   unsigned int GetNumberOfSections() const;
  77
  78   /** Get the position of a DYNAMIC section header entry.  Returns
  79       zero on error.  */
  80   unsigned long GetDynamicEntryPosition(int index) const;
  81
  82   /** Get a copy of all the DYNAMIC section header entries.
  83       Returns an empty vector on error */
  84   DynamicEntryList GetDynamicEntries() const;
  85
  86   /** Encodes a DYNAMIC section header entry list into a char vector according
  87       to the type of ELF file this is */
  88   std::vector<char> EncodeDynamicEntries(
  89     const DynamicEntryList& entries) const;
  90
  91   /** Get the SONAME field if any.  */
  92   bool GetSOName(std::string& soname);
  93   StringEntry const* GetSOName();
  94
  95   /** Get the RPATH field if any.  */
  96   StringEntry const* GetRPath();
  97
  98   /** Get the RUNPATH field if any.  */
  99   StringEntry const* GetRunPath();
 100
 101   /** Returns true if the ELF file targets a MIPS CPU.  */
 102   bool IsMIPS() const;
 103
 104   /** Print human-readable information about the ELF file.  */
 105   void PrintInfo(std::ostream& os) const;
 106
 107   /** Interesting dynamic tags.
 108       If the tag is 0, it does not exist in the host ELF implementation */
 109   static const long TagRPath, TagRunPath, TagMipsRldMapRel;
 110
 111 private:
 112   friend class cmELFInternal;
 113   bool Valid() const;
 114   std::unique_ptr<cmELFInternal> Internal;
 115   std::string ErrorMessage;
 116 };