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, 117 insertions, 0 deletions

diff --git a/src/client/linux/minidump_writer/linux_core_dumper_unittest.cc b/src/client/linux/minidump_writer/linux_core_dumper_unittest.cc
new file mode 100644
index 00000000..e335413b
--- /dev/null
+++ b/src/client/linux/minidump_writer/linux_core_dumper_unittest.cc
@@ -0,0 +1,117 @@
+// 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_unittest.cc:
+// Unit tests for google_breakpad::LinuxCoreDumoer.
+
+#include "breakpad_googletest_includes.h"
+#include "client/linux/minidump_writer/linux_core_dumper.h"
+#include "common/linux/tests/crash_generator.h"
+
+using std::string;
+using namespace google_breakpad;
+
+TEST(LinuxCoreDumperTest, BuildProcPath) {
+  const pid_t pid = getpid();
+  const char procfs_path[] = "/procfs_copy";
+  LinuxCoreDumper dumper(getpid(), "core_file", procfs_path);
+
+  char maps_path[NAME_MAX] = "";
+  char maps_path_expected[NAME_MAX];
+  snprintf(maps_path_expected, sizeof(maps_path_expected),
+           "%s/maps", procfs_path);
+  EXPECT_TRUE(dumper.BuildProcPath(maps_path, pid, "maps"));
+  EXPECT_STREQ(maps_path_expected, maps_path);
+
+  EXPECT_FALSE(dumper.BuildProcPath(NULL, pid, "maps"));
+  EXPECT_FALSE(dumper.BuildProcPath(maps_path, pid, ""));
+  EXPECT_FALSE(dumper.BuildProcPath(maps_path, pid, NULL));
+
+  char long_node[NAME_MAX];
+  size_t long_node_len = NAME_MAX - strlen(procfs_path) - 1;
+  memset(long_node, 'a', long_node_len);
+  long_node[long_node_len] = '\0';
+  EXPECT_FALSE(dumper.BuildProcPath(maps_path, pid, long_node));
+}
+
+TEST(LinuxCoreDumperTest, VerifyDumpWithMultipleThreads) {
+  CrashGenerator crash_generator;
+  if (!crash_generator.HasDefaultCorePattern()) {
+    fprintf(stderr, "LinuxCoreDumperTest.VerifyDumpWithMultipleThreads test"
+            "is skipped due to non-default core pattern\n");
+    return;
+  }
+
+  const unsigned kNumOfThreads = 3;
+  const unsigned kCrashThread = 1;
+  const int kCrashSignal = SIGABRT;
+  pid_t child_pid;
+  // TODO(benchan): Revert to use ASSERT_TRUE once the flakiness in
+  // CrashGenerator is identified and fixed.
+  if (!crash_generator.CreateChildCrash(kNumOfThreads, kCrashThread,
+                                        kCrashSignal, &child_pid)) {
+    fprintf(stderr, "LinuxCoreDumperTest.VerifyDumpWithMultipleThreads test"
+            "is skipped due to no core dump generated\n");
+    return;
+  }
+
+  pid_t pid = getpid();
+  const char* core_file = crash_generator.GetCoreFilePath().c_str();
+
+  // Since CrashGenerator::CreateChildCrash() simply crashed a fork of
+  // this process, we expect that those proc files, which are used by
+  // LinuxCoreDumper, of crashed child process have the same content of
+  // this process. So we simply pass the proc files of this process to
+  // LinuxCoreDumper.
+  char procfs_path[NAME_MAX];
+  snprintf(procfs_path, NAME_MAX, "/proc/%d", pid);
+
+  LinuxCoreDumper dumper(child_pid, core_file, procfs_path);
+  dumper.Init();
+
+  EXPECT_TRUE(dumper.IsPostMortem());
+
+  // These are no-ops and should always return true.
+  EXPECT_TRUE(dumper.ThreadsSuspend());
+  EXPECT_TRUE(dumper.ThreadsResume());
+
+  // LinuxCoreDumper cannot determine the crash address and thus it always
+  // sets the crash address to 0.
+  EXPECT_EQ(0, dumper.crash_address());
+  EXPECT_EQ(kCrashSignal, dumper.crash_signal());
+  EXPECT_EQ(crash_generator.GetThreadId(kCrashThread),
+            dumper.crash_thread());
+
+  EXPECT_EQ(kNumOfThreads, dumper.threads().size());
+  for (unsigned i = 0; i < kNumOfThreads; ++i) {
+    ThreadInfo info;
+    EXPECT_TRUE(dumper.GetThreadInfoByIndex(i, &info));
+    EXPECT_EQ(getpid(), info.ppid);
+  }
+}