Add utilities for processing Linux core dump files.

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. Add an ElfCoreDump class for processing Linux core dump files, which will
   later be used to implement the core dump to minidump conversion.
2. Add a CrashGenerator class for generating a crash with a core dump file
   for testing the functionalities of ElfCoreDump.
3. Move some utility functions for reading/writing files to file_utils.h.

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.
Review URL: http://breakpad.appspot.com/337001

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@900 4c0a9323-5329-0410-9bdc-e9ce6186880e

1 files changed, 108 insertions, 0 deletions

diff --git a/src/common/linux/tests/crash_generator.h b/src/common/linux/tests/crash_generator.h
new file mode 100644
index 00000000..c88a8920
--- /dev/null
+++ b/src/common/linux/tests/crash_generator.h
@@ -0,0 +1,108 @@
+// Copyright (c) 2011, 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.
+
+// crash_generator.h: Define the google_breakpad::CrashGenerator class,
+// which is used to generate a crash (and a core dump file) for testing.
+
+#ifndef COMMON_LINUX_TESTS_CRASH_GENERATOR_H_
+#define COMMON_LINUX_TESTS_CRASH_GENERATOR_H_
+
+#include <sys/resource.h>
+
+#include <string>
+
+#include "common/tests/auto_tempdir.h"
+
+namespace google_breakpad {
+
+// A utility class for generating a crash (and a core dump file) for
+// testing. It creates a child process with the specified number of
+// threads, which is then termainated by the specified signal. A core
+// dump file is expected to be created upon the termination of the child
+// process, which can then be used for testing code that processes core
+// dump files.
+class CrashGenerator {
+ public:
+  CrashGenerator();
+
+  ~CrashGenerator();
+
+  // Returns true if a core dump file named 'core' will be generated in
+  // the current directory for a test that produces a crash by checking
+  // if /proc/sys/kernel/core_pattern has the default value 'core'.
+  bool HasDefaultCorePattern() const;
+
+  // Sets the maximum size of core dump file (both the soft and hard limit)
+  // to |limit| bytes. Returns true on success.
+  bool SetCoreFileSizeLimit(rlim_t limit) const;
+
+  // Returns the expected path of the core dump file.
+  std::string GetCoreFilePath() const;
+
+  // Creates a crash (and a core dump file) by creating a child process with
+  // |num_threads| threads, and the terminating the child process by sending
+  // a signal with number |crash_signal| to the |crash_thread|-th thread.
+  // Returns true on success.
+  bool CreateChildCrash(unsigned num_threads, unsigned crash_thread,
+                        int crash_signal);
+
+  // Creates |num_threads| threads in the child process.
+  void CreateThreadsInChildProcess(unsigned num_threads);
+
+  // Returns the thread ID of the |index|-th thread in the child process.
+  // This method does not validate |index|.
+  pid_t GetThreadId(unsigned index) const;
+
+ private:
+  // Creates a shared memory of |memory_size| bytes for communicating thread
+  // IDs between the parent and child process. Returns true on success.
+  bool MapSharedMemory(size_t memory_size);
+
+  // Releases any shared memory created by MapSharedMemory(). Returns true on
+  // success.
+  bool UnmapSharedMemory();
+
+  // Returns the pointer to the thread ID of the |index|-th thread in the child
+  // process. This method does not validate |index|.
+  pid_t* GetThreadIdPointer(unsigned index);
+
+  // Temporary directory in which a core file is generated.
+  AutoTempDir temp_dir_;
+
+  // Shared memory for communicating thread IDs between the parent and
+  // child process.
+  void* shared_memory_;
+
+  // Number of bytes mapped for |shared_memory_|.
+  size_t shared_memory_size_;
+};
+
+}  // namespace google_breakpad
+
+#endif  // COMMON_LINUX_TESTS_CRASH_GENERATOR_H_