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

src/common/tests/auto_tempdir.h

@@ -59,9 +59,9 @@ class AutoTempDir {
     DeleteRecursively(path_);
   }
 
- const std::string& path() {
-   return path_;
- }
+  const std::string& path() const {
+    return path_;
+  }
 
  private:
   void DeleteRecursively(const std::string& path) {

src/common/tests/file_utils.cc

@@ -0,0 +1,97 @@
+// 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.
+
+// file_utils.cc: Implement utility functions for file manipulation.
+// See file_utils.h for details.
+
+#include <fcntl.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "common/linux/eintr_wrapper.h"
+#include "common/tests/file_utils.h"
+
+namespace google_breakpad {
+
+bool ReadFile(const char* path, void* buffer, ssize_t* buffer_size) {
+  int fd = HANDLE_EINTR(open(path, O_RDONLY));
+  if (fd == -1) {
+    perror("open");
+    return false;
+  }
+
+  bool ok = true;
+  if (buffer && buffer_size && *buffer_size > 0) {
+    memset(buffer, 0, sizeof(*buffer_size));
+    *buffer_size = HANDLE_EINTR(read(fd, buffer, *buffer_size));
+    if (*buffer_size == -1) {
+      perror("read");
+      ok = false;
+    }
+  }
+  if (HANDLE_EINTR(close(fd)) == -1) {
+    perror("close");
+    ok = false;
+  }
+  return ok;
+}
+
+bool WriteFile(const char* path, const void* buffer, size_t buffer_size) {
+  int fd = HANDLE_EINTR(open(path, O_CREAT | O_TRUNC | O_WRONLY, S_IRWXU));
+  if (fd == -1) {
+    perror("open");
+    return false;
+  }
+
+  bool ok = true;
+  if (buffer) {
+    size_t bytes_written_total = 0;
+    ssize_t bytes_written_partial = 0;
+    const char* data = reinterpret_cast<const char*>(buffer);
+    while (bytes_written_total < buffer_size) {
+      bytes_written_partial =
+          HANDLE_EINTR(write(fd, data + bytes_written_total,
+                             buffer_size - bytes_written_total));
+      if (bytes_written_partial < 0) {
+        perror("write");
+        ok = false;
+        break;
+      }
+      bytes_written_total += bytes_written_partial;
+    }
+  }
+  if (HANDLE_EINTR(close(fd)) == -1) {
+    perror("close");
+    ok = false;
+  }
+  return ok;
+}
+
+}  // namespace google_breakpad

src/common/tests/file_utils.h

@@ -0,0 +1,49 @@
+// 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.
+
+// file_utils.h: Define utility functions for file manipulation, which
+// are used for testing.
+
+#ifndef COMMON_TESTS_FILE_UTILS_H_
+#define COMMON_TESTS_FILE_UTILS_H_
+
+namespace google_breakpad {
+
+// Reads the content of a file at |path| into |buffer|. |buffer_size| specifies
+// the size of |buffer| in bytes and returns the number of bytes read from the
+// file on success. Returns true on success.
+bool ReadFile(const char* path, void* buffer, ssize_t* buffer_size);
+
+// Writes |buffer_size| bytes of the content in |buffer| to a file at |path|.
+// Returns true on success.
+bool WriteFile(const char* path, const void* buffer, size_t buffer_size);
+
+}  // namespace google_breakpad
+
+#endif  // COMMON_TESTS_FILE_UTILS_H_