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      1 // Copyright (c) 2011, Google Inc.
      2 // All rights reserved.
      3 //
      4 // Redistribution and use in source and binary forms, with or without
      5 // modification, are permitted provided that the following conditions are
      6 // met:
      7 //
      8 //     * Redistributions of source code must retain the above copyright
      9 // notice, this list of conditions and the following disclaimer.
     10 //     * Redistributions in binary form must reproduce the above
     11 // copyright notice, this list of conditions and the following disclaimer
     12 // in the documentation and/or other materials provided with the
     13 // distribution.
     14 //     * Neither the name of Google Inc. nor the names of its
     15 // contributors may be used to endorse or promote products derived from
     16 // this software without specific prior written permission.
     17 //
     18 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     19 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     20 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     21 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     22 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     23 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     24 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     25 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     26 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     27 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     28 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     29 
     30 // elf_core_dump.h: Define the google_breakpad::ElfCoreDump class, which
     31 // encapsulates an ELF core dump file mapped into memory.
     32 
     33 #ifndef COMMON_LINUX_ELF_CORE_DUMP_H_
     34 #define COMMON_LINUX_ELF_CORE_DUMP_H_
     35 
     36 #include <elf.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 value of __WORDSIZE.
     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 __WORDSIZE == 32
     55   static const int kClass = ELFCLASS32;
     56 #elif __WORDSIZE == 64
     57   static const int kClass = ELFCLASS64;
     58 #else
     59 #error "Unsupported __WORDSIZE 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   // Sets the core dump content to |content|.
    109   void SetContent(const MemoryRange& content);
    110 
    111   // Returns true if a valid ELF header in the core dump, or false otherwise.
    112   bool IsValid() const;
    113 
    114   // Returns the ELF header in the core dump, or NULL if no ELF header
    115   // is found in |content_|.
    116   const Ehdr* GetHeader() const;
    117 
    118   // Returns the |index|-th program header in the core dump, or NULL if no
    119   // ELF header is found in |content_| or |index| is out of bounds.
    120   const Phdr* GetProgramHeader(unsigned index) const;
    121 
    122   // Returns the first program header of |type| in the core dump, or NULL if
    123   // no ELF header is found in |content_| or no program header of |type| is
    124   // found.
    125   const Phdr* GetFirstProgramHeaderOfType(Word type) const;
    126 
    127   // Returns the number of program headers in the core dump, or 0 if no
    128   // ELF header is found in |content_|.
    129   unsigned GetProgramHeaderCount() const;
    130 
    131   // Copies |length| bytes of data starting at |virtual_address| in the core
    132   // dump to |buffer|. |buffer| should be a valid pointer to a buffer of at
    133   // least |length| bytes. Returns true if the data to be copied is found in
    134   // the core dump, or false otherwise.
    135   bool CopyData(void* buffer, Addr virtual_address, size_t length);
    136 
    137   // Returns the first note found in the note section of the core dump, or
    138   // an empty note if no note is found.
    139   Note GetFirstNote() const;
    140 
    141  private:
    142   // Core dump content.
    143   MemoryRange content_;
    144 };
    145 
    146 }  // namespace google_breakpad
    147 
    148 #endif  // COMMON_LINUX_ELF_CORE_DUMP_H_
    149