Add support for Linux memory mapping stream and remove ELF header usage

src/google_breakpad/processor/minidump.h

Index: src/google_breakpad/processor/minidump.h
===================================================================
--- src/google_breakpad/processor/minidump.h	(revision 1474)
+++ src/google_breakpad/processor/minidump.h	(working copy)
@@ -852,7 +852,100 @@
   uint32_t info_count_;
 };
 
+// MinidumpLinuxMaps wraps information about a single mapped memory region
+// from /proc/self/maps.
+class MinidumpLinuxMaps : public MinidumpObject {
+ public:
+  virtual ~MinidumpLinuxMaps();
 
+  // The memory address of the base of the mapped region.
+  uint64_t GetBase() const { return valid_ ? base_address_ : 0; }
+  // The size of the mapped region.
+  uint64_t GetSize() const { return valid_ ? region_size_ : 0; }
+
+  // The permissions of the mapped region.
+  bool IsReadable() const { return valid_ ? is_readable_ : false; }
+  bool IsWriteable() const { return valid_ ? is_writeable_ : false; }
+  bool IsExecutable() const { return valid_ ? is_executable_ : false; }
+  bool IsShared() const { return valid_ ? is_shared_ : false; }
+
+  // The offset of the mapped region.
+  uint64_t GetOffset() const { return valid_ ? offset_ : 0; }
+
+  // The major device number.
+  uint8_t GetMajorDevice() const { return valid_ ? major_device_ : 0; }
+  // The minor device number.
+  uint8_t GetMinorDevice() const { return valid_ ? minor_device_ : 0; }
+
+  // The inode of the mapped region.
+  uint32_t GetInode() const { return valid_ ? inode_ : 0; }
+
+  // The pathname of the mapped region.
+  const string GetPathname() const { return valid_ ? pathname_ : NULL; }
+
+  // Print the contents of this mapping.
+  void Print();
+
+ private:
+  // These objects are managed by MinidumpLinuxMapsList.
+  friend class MinidumpLinuxMapsList;
+
+  explicit MinidumpLinuxMaps(Minidump *minidump);

[ivanpe, 2015/07/23 01:17:12]

Please, document who should own the memory for the passed in pointer?

[liuandrew, 2015/07/24 23:25:35]

Done.

+
+  // Read data about a single mapping from /proc/self/maps and load the data
+  // into this object. The input vector is in the same format as a line from
+  // /proc/self/maps.
+  bool Read(vector<char> *data);

[ivanpe, 2015/07/23 01:17:12]

Is this an input parameter?  Passing as const vector<char>& is preferred.

[liuandrew, 2015/07/24 23:25:35]

Removed method.

+
+  // Instance variables.

[ivanpe, 2015/07/23 01:17:12]

This comment is not very useful.  Please, comment the individual members or
maybe just provide an URL to a place where these fields are already documented.

[liuandrew, 2015/07/24 23:25:35]

Removed these instance variables.

+  uint64_t base_address_;
+  uint64_t region_size_;
+  bool is_readable_;
+  bool is_writeable_;
+  bool is_executable_;
+  bool is_shared_;
+  uint64_t offset_;
+  uint8_t major_device_;
+  uint8_t minor_device_;
+  uint32_t inode_;
+  string pathname_;
+  vector<char> *raw_linux_maps_;
+};

[ivanpe, 2015/07/23 01:17:12]

DISALLOW_COPY_AND_ASSIGN(MinidumpLinuxMaps);

[liuandrew, 2015/07/24 23:25:35]

Why do I need this? What does it do? The other classes in this file do not have
it.

[ivanpe, 2015/07/27 18:12:42]

If you do not want to support copy/move operations on your type, you should
explicitly disable them using = delete or DISALLOW_COPY_AND_ASSIGN.

https://google-styleguide.googlecode.com/svn/trunk/cppguide.html#Copyable_Mov...

[liuandrew, 2015/07/27 23:09:26]

Done.

+
+// MinidumpLinuxMapsList corresponds to the Linux-exclusive MD_LINUX_MAPS
+// stream, which contains the contents of /prod/self/maps, which contains
+// the mapped memory regions and their access permissions.
+class MinidumpLinuxMapsList : public MinidumpStream {
+ public:
+  virtual ~MinidumpLinuxMapsList();
+
+  // Get mapping at the given memory address.
+  const MinidumpLinuxMaps *GetLinuxMapsForAddress(uint64_t address) const;

[ivanpe, 2015/07/23 01:17:12]

Please, document who owns the memory for the returned pointer (caller or
callee)!

[liuandrew, 2015/07/24 23:25:36]

Done.

+  // Get mapping at the given index.
+  const MinidumpLinuxMaps *GetLinuxMapsAtIndex(unsigned int index) const;

[ivanpe, 2015/07/23 01:17:12]

Please, document who owns the memory for the returned pointer (caller or
callee)!

[liuandrew, 2015/07/24 23:25:35]

Done.

+
+  // Print the contents of /proc/self/maps to stdout.
+  void Print();
+
+ private:
+  friend class Minidump;
+
+  typedef vector<MinidumpLinuxMaps *> MinidumpLinuxMappings;
+
+  static const uint32_t kStreamType = MD_LINUX_MAPS;
+
+  explicit MinidumpLinuxMapsList(Minidump *minidump);

[ivanpe, 2015/07/23 01:17:12]

Again, please, describe who owns the passed in pointer.

[liuandrew, 2015/07/24 23:25:35]

Done.

+
+  // Read and load the contents of the process mapping data.
+  // The stream should have data in the form of /proc/self/maps.
+  bool Read(uint32_t expected_size);

[ivanpe, 2015/07/23 01:17:12]

Please, document return value?  What happens when the expected size is different
from the actual one?

[liuandrew, 2015/07/24 23:25:36]

Done.

+
+  // Instance variables.

[ivanpe, 2015/07/23 01:17:12]

Please, document the individual members instead.

[liuandrew, 2015/07/24 23:25:35]

Done.

+  MinidumpLinuxMappings *maps_;
+  uint32_t maps_count_;
+  vector<char> raw_linux_maps_list_;
+};

[ivanpe, 2015/07/23 01:17:12]

DISALLOW_COPY_AND_ASSIGN(MinidumpLinuxMapsList);

[liuandrew, 2015/07/24 23:25:35]

See response for similar comment.

[ivanpe, 2015/07/27 18:12:41]

Please, take a look at my other response.  Thanks.

[liuandrew, 2015/07/27 23:09:26]

Done.

+
 // Minidump is the user's interface to a minidump file.  It wraps MDRawHeader
 // and provides access to the minidump's top-level stream directory.
 class Minidump {
@@ -912,6 +1005,9 @@
   virtual MinidumpBreakpadInfo* GetBreakpadInfo();
   virtual MinidumpMemoryInfoList* GetMemoryInfoList();
 
+  // The next method also calls GetStream, but is exclusive for Linux dumps.
+  virtual MinidumpLinuxMapsList *GetLinuxMapsList();
+
   // The next set of methods are provided for users who wish to access
   // data in minidump files directly, while leveraging the rest of
   // this class and related classes to handle the basic minidump