1  // Copyright 2011 Google LLC
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 28  
 29  // elf_core_dump.h: Define the google_breakpad::ElfCoreDump class, which
 30  // encapsulates an ELF core dump file mapped into memory.
 31  
 32  #ifndef COMMON_LINUX_ELF_CORE_DUMP_H_
 33  #define COMMON_LINUX_ELF_CORE_DUMP_H_
 34  
 35  #include <elf.h>
 36  #include <limits.h>
 37  #include <link.h>
 38  #include <stddef.h>
 39  
 40  #include "common/memory_range.h"
 41  
 42  namespace google_breakpad {
 43  
 44  // A class encapsulating an ELF core dump file mapped into memory, which
 45  // provides methods for accessing program headers and the note section.
 46  class ElfCoreDump {
 47   public:
 48    // ELF types based on the native word size.
 49    typedef ElfW(Ehdr) Ehdr;
 50    typedef ElfW(Nhdr) Nhdr;
 51    typedef ElfW(Phdr) Phdr;
 52    typedef ElfW(Word) Word;
 53    typedef ElfW(Addr) Addr;
 54  #if ULONG_MAX == 0xffffffff
 55    static const int kClass = ELFCLASS32;
 56  #elif ULONG_MAX == 0xffffffffffffffff
 57    static const int kClass = ELFCLASS64;
 58  #else
 59  #error "Unsupported word size for ElfCoreDump."
 60  #endif
 61  
 62    // A class encapsulating the note content in a core dump, which provides
 63    // methods for accessing the name and description of a note.
 64    class Note {
 65     public:
 66      Note();
 67  
 68      // Constructor that takes the note content from |content|.
 69      explicit Note(const MemoryRange& content);
 70  
 71      // Returns true if this note is valid, i,e. a note header is found in
 72      // |content_|, or false otherwise.
 73      bool IsValid() const;
 74  
 75      // Returns the note header, or NULL if no note header is found in
 76      // |content_|.
 77      const Nhdr* GetHeader() const;
 78  
 79      // Returns the note type, or 0 if no note header is found in |content_|.
 80      Word GetType() const;
 81  
 82      // Returns a memory range covering the note name, or an empty range
 83      // if no valid note name is found in |content_|.
 84      MemoryRange GetName() const;
 85  
 86      // Returns a memory range covering the note description, or an empty
 87      // range if no valid note description is found in |content_|.
 88      MemoryRange GetDescription() const;
 89  
 90      // Returns the note following this note, or an empty note if no valid
 91      // note is found after this note.
 92      Note GetNextNote() const;
 93  
 94     private:
 95      // Returns the size in bytes round up to the word alignment, specified
 96      // for the note section, of a given size in bytes.
 97      static size_t AlignedSize(size_t size);
 98  
 99      // Note content.
100      MemoryRange content_;
101    };
102  
103    ElfCoreDump();
104  
105    // Constructor that takes the core dump content from |content|.
106    explicit ElfCoreDump(const MemoryRange& content);
107  
108    ~ElfCoreDump();
109  
110    // Sets the core dump content to |content|.
111    void SetContent(const MemoryRange& content);
112  
113    // Returns true if a valid ELF header in the core dump, or false otherwise.
114    bool IsValid() const;
115  
116    // Returns the ELF header in the core dump, or NULL if no ELF header
117    // is found in |content_|.
118    const Ehdr* GetHeader() const;
119  
120    // Returns the |index|-th program header in the core dump, or NULL if no
121    // ELF header is found in |content_| or |index| is out of bounds.
122    const Phdr* GetProgramHeader(unsigned index) const;
123  
124    // Returns the first program header of |type| in the core dump, or NULL if
125    // no ELF header is found in |content_| or no program header of |type| is
126    // found.
127    const Phdr* GetFirstProgramHeaderOfType(Word type) const;
128  
129    // Returns the number of program headers in the core dump, or 0 if no
130    // ELF header is found in |content_|.
131    unsigned GetProgramHeaderCount() const;
132  
133    // Copies |length| bytes of data starting at |virtual_address| in the core
134    // dump to |buffer|. |buffer| should be a valid pointer to a buffer of at
135    // least |length| bytes. Returns true if the data to be copied is found in
136    // the core dump, or false otherwise.
137    bool CopyData(void* buffer, Addr virtual_address, size_t length);
138  
139    // Returns the first note found in the note section of the core dump, or
140    // an empty note if no note is found.
141    Note GetFirstNote() const;
142  
143    // Sets the mem fd.
144    void SetProcMem(const int fd);
145  
146   private:
147    // Core dump content.
148    MemoryRange content_;
149  
150    // Descriptor for /proc/<pid>/mem.
151    int proc_mem_fd_;
152  };
153  
154  }  // namespace google_breakpad
155  
156  #endif  // COMMON_LINUX_ELF_CORE_DUMP_H_