Implement core dump to minidump conversion.

This patch is part of a bigger patch that helps merging the breakpad code
with the modified version in Chromium OS.

Specifically, this patch makes the following changes:
1. Turn the LinuxDumper class into a base class and move ptrace related
   code into a new derived class, LinuxPtraceDumper.
2. Add a LinuxCoreDumper class, which is derived from LinuxDumper, to
   extract information from a crashed process via a core dump file instead
   of ptrace.
3. Add a WriteMinidumpFromCore function to
     src/client/linux/minidump_writer/minidump_writer.h,
   which uses LinuxCoreDumper to extract information from a core dump file.
4. Add a core2md utility, which simply wraps WriteMinidumpFromCore, for
   converting a core dump to a minidump.

BUG=455
TEST=Tested the following:
1. Build on 32-bit and 64-bit Linux with gcc 4.4.3 and gcc 4.6.
2. Build on Mac OS X 10.6.8 with gcc 4.2 and clang 3.0 (with latest gmock).
3. All unit tests pass.
4. Run Chromium OS tests to test core2md.
Review URL: http://breakpad.appspot.com/343001

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@905 4c0a9323-5329-0410-9bdc-e9ce6186880e

1 files changed, 122 insertions, 0 deletions

diff --git a/src/client/linux/minidump_writer/linux_core_dumper.h b/src/client/linux/minidump_writer/linux_core_dumper.h
new file mode 100644
index 00000000..edb9e738
--- /dev/null
+++ b/src/client/linux/minidump_writer/linux_core_dumper.h
@@ -0,0 +1,122 @@
+// Copyright (c) 2012, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// linux_core_dumper.h: Define the google_breakpad::LinuxCoreDumper
+// class, which is derived from google_breakpad::LinuxDumper to extract
+// information from a crashed process via its core dump and proc files.
+
+#ifndef CLIENT_LINUX_MINIDUMP_WRITER_LINUX_CORE_DUMPER_H_
+#define CLIENT_LINUX_MINIDUMP_WRITER_LINUX_CORE_DUMPER_H_
+
+#include "client/linux/minidump_writer/linux_dumper.h"
+#include "common/linux/elf_core_dump.h"
+#include "common/linux/memory_mapped_file.h"
+
+namespace google_breakpad {
+
+class LinuxCoreDumper : public LinuxDumper {
+ public:
+  // Constructs a dumper for extracting information of a given process
+  // with a process ID of |pid| via its core dump file at |core_path| and
+  // its proc files at |procfs_path|. If |procfs_path| is a copy of
+  // /proc/<pid>, it should contain the following files:
+  //     auxv, cmdline, environ, exe, maps, status
+  LinuxCoreDumper(pid_t pid, const char* core_path, const char* procfs_path);
+
+  // Implements LinuxDumper::BuildProcPath().
+  // Builds a proc path for a certain pid for a node (/proc/<pid>/<node>).
+  // |path| is a character array of at least NAME_MAX bytes to return the
+  // result.|node| is the final node without any slashes. Return true on
+  // success.
+  //
+  // As this dumper performs a post-mortem dump and makes use of a copy
+  // of the proc files of the crashed process, this derived method does
+  // not actually make use of |pid| and always returns a subpath of
+  // |procfs_path_| regardless of whether |pid| corresponds to the main
+  // process or a thread of the process, i.e. assuming both the main process
+  // and its threads have the following proc files with the same content:
+  //     auxv, cmdline, environ, exe, maps, status
+  virtual bool BuildProcPath(char* path, pid_t pid, const char* node) const;
+
+  // Implements LinuxDumper::CopyFromProcess().
+  // Copies content of |length| bytes from a given process |child|,
+  // starting from |src|, into |dest|. This method extracts the content
+  // the core dump and fills |dest| with a sequence of marker bytes
+  // if the expected data is not found in the core dump.
+  virtual void CopyFromProcess(void* dest, pid_t child, const void* src,
+                               size_t length);
+
+  // Implements LinuxDumper::GetThreadInfoByIndex().
+  // Reads information about the |index|-th thread of |threads_|.
+  // Returns true on success. One must have called |ThreadsSuspend| first.
+  virtual bool GetThreadInfoByIndex(size_t index, ThreadInfo* info);
+
+  // Implements LinuxDumper::IsPostMortem().
+  // Always returns true to indicate that this dumper performs a
+  // post-mortem dump of a crashed process via a core dump file.
+  virtual bool IsPostMortem() const;
+
+  // Implements LinuxDumper::ThreadsSuspend().
+  // As the dumper performs a post-mortem dump via a core dump file,
+  // there is no threads to suspend. This method does nothing and
+  // always returns true.
+  virtual bool ThreadsSuspend();
+
+  // Implements LinuxDumper::ThreadsResume().
+  // As the dumper performs a post-mortem dump via a core dump file,
+  // there is no threads to resume. This method does nothing and
+  // always returns true.
+  virtual bool ThreadsResume();
+
+ protected:
+  // Implements LinuxDumper::EnumerateThreads().
+  // Enumerates all threads of the given process into |threads_|.
+  virtual bool EnumerateThreads();
+
+ private:
+  // Path of the core dump file.
+  const char* core_path_;
+
+  // Path of the directory containing the proc files of the given process,
+  // which is usually a copy of /proc/<pid>.
+  const char* procfs_path_;
+
+  // Memory-mapped core dump file at |core_path_|.
+  MemoryMappedFile mapped_core_file_;
+
+  // Content of the core dump file.
+  ElfCoreDump core_;
+
+  // Thread info found in the core dump file.
+  wasteful_vector<ThreadInfo> thread_infos_;
+};
+
+}  // namespace google_breakpad
+
+#endif  // CLIENT_LINUX_HANDLER_LINUX_CORE_DUMPER_H_