Adding a SW reporter component updater

chrome/browser/component_updater/sw_reporter_component_installer_win.cc

+// Copyright (c) 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/browser/component_updater/sw_reporter_component_installer_win.h"
+
+#include <string>
+#include <vector>
+
+#include "base/base_paths.h"
+#include "base/bind.h"
+#include "base/bind_helpers.h"
+#include "base/command_line.h"
+#include "base/file_util.h"
+#include "base/files/file_enumerator.h"
+#include "base/files/file_path.h"
+#include "base/logging.h"
+#include "base/metrics/histogram.h"
+#include "base/metrics/sparse_histogram.h"
+#include "base/path_service.h"
+#include "base/prefs/pref_registry_simple.h"
+#include "base/prefs/pref_service.h"
+#include "base/process/kill.h"
+#include "base/process/launch.h"
+#include "base/task_runner_util.h"
+#include "base/threading/worker_pool.h"
+#include "base/values.h"
+#include "base/win/registry.h"
+#include "chrome/browser/browser_process.h"
+#include "chrome/browser/component_updater/component_updater_service.h"
+#include "chrome/common/chrome_paths.h"
+#include "chrome/common/pref_names.h"
+#include "content/public/browser/browser_thread.h"
+
+using content::BrowserThread;
+
+namespace component_updater {
+
+namespace {
+
+// These values are used to send UMA information and are replicated in the
+// histograms.xml file, so the order MUST NOT CHANGE.
+enum SwReporterUmaValue {
+  SW_REPORTER_START_DOWNLOAD = 0,
+  SW_REPORTER_RETRYING_DOWNLOAD,
+  SW_REPORTER_RETRIED_TOO_MANY_DOWNLOADS,
+  SW_REPORTER_START_EXECUTION,
+  SW_REPORTER_RETRYING_EXECUTION,
+  SW_REPORTER_RETRIED_TOO_MANY_EXECUTIONS,
+  SW_REPORTER_COMPONENT_UPDATE_ERROR,
+  SW_REPORTER_MAX,
+};
+
+// The maximum number of times to retry a download on startup.
+const int kMaxRetry = 7;
+
+// CRX hash. The extension id is: gkmgaooipdjhmangpemjhigmamcehddo.
+// hashlib.sha256().update(open(".crx").read()[16:16+294]).digest().

[cpu_(ooo_6.6-7.5), 2014/06/18 01:58:36]

a comment with python in a c++ file, we must go deeper : )

[MAD, 2014/06/18 14:49:53]

Yeah, it took me a while to figure out how these values were generated, I
couldn't find any documentation anywhere about it, so I thought I would add
some... :-)

+const uint8 kSha2Hash[] = {0x6a, 0xc6, 0x0e, 0xe8, 0xf3, 0x97, 0xc0, 0xd6,
+                           0xf4, 0xc9, 0x78, 0x6c, 0x0c, 0x24, 0x73, 0x3e,
+                           0x05, 0xa5, 0x62, 0x4b, 0x2e, 0xc7, 0xb7, 0x1c,
+                           0x5f, 0xea, 0xf0, 0x88, 0xf6, 0x97, 0x9b, 0xc7};
+
+const char kSwReporterManifestName[] = "Software Reporter Tool";
+
+const base::FilePath::CharType kSwReporterExeName[] =
+    FILE_PATH_LITERAL("software_reporter_tool.exe");
+const base::FilePath::CharType kSwReporterBaseDirectory[] =
+    FILE_PATH_LITERAL("SwReporter");
+
+// If we don't have a SwReporter component, this is the version we claim.
+const char kNullVersion[] = "0.0.0.0";
+
+// Where to fetch the reporter exit code in the registry.
+const wchar_t kSoftwareRemovalToolRegistryKey[] =
+    L"Software\\Google\\Software Removal Tool";
+const wchar_t kExitCodeRegistryValueName[] = L"ExitCode";
+
+void ReportSwReporterStep(SwReporterUmaValue value) {
+  UMA_HISTOGRAM_ENUMERATION(
+      "ComponentUpdater.SwReporterStep", value, SW_REPORTER_MAX);
+}
+
+// This function is called on the UI thread to report the SwReporter exit code
+// and then to clear it from the registry as well as clear the execution state
+// from the local state.
+void ReportAndClearSwReporterExitCode(int exit_code) {
+  UMA_HISTOGRAM_SPARSE_SLOWLY("ComponentUpdater.SwReporterExitCode", exit_code);
+
+  base::win::RegKey srt_key(
+      HKEY_CURRENT_USER, kSoftwareRemovalToolRegistryKey, KEY_WRITE);
+  srt_key.DeleteValue(kExitCodeRegistryValueName);
+
+  // Now that we are done we can reset the try count.
+  g_browser_process->local_state()->SetInteger(
+      prefs::kSwReporterComponentExecuteTryCount, 0);
+}
+
+// This function is called from a worker thread to wait for the SwReporter to
+// complete and then collect it's exit code.
+int WaitForProcessTermination(base::ProcessHandle process_handle) {
+  int exit_code = -1;
+  bool success = base::WaitForExitCode(process_handle, &exit_code);
+  DCHECK(success);
+  ::CloseHandle(process_handle);
+  process_handle = NULL;
+  return exit_code;
+}
+
+void MaybeExecuteReporter(const base::FilePath& new_version_path,
+                          PrefService* prefs) {
+  // If we get here without a register or an execute try count, this means that
+  // the component have been silently updated to a new version, so we don't want
+  // to execute.
+  int execute_try_count =
+      prefs->GetInteger(prefs::kSwReporterComponentExecuteTryCount);
+  if (execute_try_count == 0 &&
+      prefs->GetInteger(prefs::kSwReporterComponentRegisterTryCount) == 0) {
+    return;
+  }
+
+  // We're done with the registration so clear the number of retries,
+  prefs->SetInteger(prefs::kSwReporterComponentRegisterTryCount, 0);
+
+  ReportSwReporterStep(execute_try_count ? SW_REPORTER_RETRYING_EXECUTION
+                                         : SW_REPORTER_START_EXECUTION);
+  prefs->SetInteger(prefs::kSwReporterComponentExecuteTryCount,
+                    execute_try_count + 1);
+
+  // Installation is done. Now execute the reporter.
+  base::CommandLine reporter_command_line(
+      new_version_path.Append(kSwReporterExeName));
+  base::ProcessHandle scan_reporter_process = NULL;
+  bool success = base::LaunchProcess(
+      reporter_command_line, base::LaunchOptions(), &scan_reporter_process);
+  if (success) {
+    success = base::PostTaskAndReplyWithResult(
+        base::WorkerPool::GetTaskRunner(true),
+        FROM_HERE,
+        base::Bind(&WaitForProcessTermination, scan_reporter_process),
+        base::Bind(&ReportAndClearSwReporterExitCode));
+    // WaitForProcessTermination will close the handle.
+    scan_reporter_process = NULL;
+  } else {
+    NOTREACHED() << "Could not execute from " << new_version_path.value();
+  }
+}
+
+// The base directory on windows looks like:
+// <profile>\AppData\Local\Google\Chrome\User Data\SwReporter\.
+base::FilePath GetSwReporterBaseDirectory() {
+  base::FilePath result;
+  PathService::Get(chrome::DIR_USER_DATA, &result);
+  return result.Append(kSwReporterBaseDirectory);
+}
+
+// SwReporter has version encoded in the path itself so we need to enumerate the
+// directories to find the full path. On success it returns something like:
+// <profile>\AppData\Local\Google\Chrome\User Data\SwReporter\1.0.1.5\.
+bool GetLatestSwReporterDirectory(base::FilePath* latest_version_path,
+                                  Version* latest_version,
+                                  std::vector<base::FilePath>* older_dirs) {
+  base::FilePath base_dir = GetSwReporterBaseDirectory();
+  bool found = false;
+  base::FileEnumerator file_enumerator(
+      base_dir, false, base::FileEnumerator::DIRECTORIES);
+  for (base::FilePath path = file_enumerator.Next(); !path.value().empty();
+       path = file_enumerator.Next()) {
+    Version version(path.BaseName().MaybeAsASCII());
+    if (!version.IsValid())
+      continue;
+    if (version.CompareTo(*latest_version) > 0 &&
+        base::PathExists(path.Append(kSwReporterExeName))) {
+      if (found && older_dirs)
+        older_dirs->push_back(*latest_version_path);
+      *latest_version = version;
+      *latest_version_path = path;
+      found = true;
+    } else {
+      if (older_dirs)
+        older_dirs->push_back(path);
+    }
+  }
+  return found;
+}
+
+class SwReporterComponentInstaller : public ComponentInstaller {
+ public:
+  explicit SwReporterComponentInstaller(const Version& version,
+                                        PrefService* prefs);
+  virtual ~SwReporterComponentInstaller() {}
+
+  // ComponentInstaller overrides.
+  virtual void OnUpdateError(int error) OVERRIDE;
+  virtual bool Install(const base::DictionaryValue& manifest,
+                       const base::FilePath& unpack_path) OVERRIDE;
+  virtual bool GetInstalledFile(const std::string& file,
+                                base::FilePath* installed_file) OVERRIDE;
+
+ private:
+  Version current_version_;
+  PrefService* prefs_;
+};
+
+SwReporterComponentInstaller::SwReporterComponentInstaller(
+    const Version& version,
+    PrefService* prefs)
+    : current_version_(version), prefs_(prefs) {
+  DCHECK(version.IsValid());
+  DCHECK(prefs_);
+}
+
+void SwReporterComponentInstaller::OnUpdateError(int error) {
+  ReportSwReporterStep(SW_REPORTER_COMPONENT_UPDATE_ERROR);
+  NOTREACHED() << "SwReporter update error: " << error;
+}
+
+bool SwReporterComponentInstaller::Install(
+    const base::DictionaryValue& manifest,
+    const base::FilePath& unpack_path) {
+  std::string name;
+  manifest.GetStringASCII("name", &name);
+  if (name != kSwReporterManifestName)
+    return false;
+
+  std::string proposed_version;
+  manifest.GetStringASCII("version", &proposed_version);
+  Version new_version(proposed_version.c_str());
+  if (!new_version.IsValid())
+    return false;
+
+  base::FilePath sw_reporter_path(GetSwReporterBaseDirectory());
+  base::FilePath new_version_path(
+      sw_reporter_path.AppendASCII(proposed_version));
+  if (current_version_.CompareTo(new_version) < 0) {
+    // If the latest version identified is current_version_, then
+    // new_version_path should not exist.
+    DCHECK(!base::PathExists(new_version_path));
+    if (!base::PathExists(unpack_path.Append(kSwReporterExeName)) ||
+        !base::Move(unpack_path, new_version_path)) {
+      PLOG(ERROR) << "Couldn't move files to new_version_path.\n"
+                  << unpack_path.value() << " -> " << new_version_path.value();
+      return false;
+    }
+  } else {
+    // We should never get an older version than the current one.
+    DCHECK(current_version_.CompareTo(new_version) == 0);
+    if (!base::PathExists(new_version_path.Append(kSwReporterExeName))) {
+      PLOG(INFO) << "existing version_path doesn't contain file.";
+      return false;
+    }
+  }
+
+  // Installation is over, now check if we have a pending execution.
+  BrowserThread::PostTask(

[cpu_(ooo_6.6-7.5), 2014/06/18 01:58:36]

in general this is kind of weird, I would expect to see a call to shellexecute
or createproces s from this thread.

Also, are we calling createprocess from the UI thread? if so please don't.

[MAD, 2014/06/18 14:49:53]

We use base::LaunchProcess, I was surprised that it didn't complain that I was
calling it from the UI thread... Moved it to the worker thread...

+      BrowserThread::UI,
+      FROM_HERE,
+      base::Bind(&MaybeExecuteReporter, new_version_path, prefs_));
+  return true;
+}
+
+bool SwReporterComponentInstaller::GetInstalledFile(
+    const std::string& file,
+    base::FilePath* installed_file) {
+  return false;
+}
+
+// Complete the registration of the component on the UI thread...
+void RegisterSwReporterComponent(ComponentUpdateService* cus,
+                                 const Version& version,
+                                 PrefService* prefs) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+
+  CrxComponent SwReporter;
+  SwReporter.name = "SwReporter";
+  SwReporter.installer = new SwReporterComponentInstaller(version, prefs);
+  SwReporter.version = version;
+  SwReporter.pk_hash.assign(kSha2Hash, &kSha2Hash[sizeof(kSha2Hash)]);
+  if (cus->RegisterComponent(SwReporter) == ComponentUpdateService::kError)
+    NOTREACHED() << "SwReporter component registration fail";
+}
+
+// Check if there already is a version of SwReporter installed, and if so
+// register it.
+void ExecuteSwReporterComponentOnFileThread(ComponentUpdateService* cus,
+                                            PrefService* prefs) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
+  base::FilePath base_dir = GetSwReporterBaseDirectory();
+  if (!base::PathExists(base_dir)) {
+    if (!base::CreateDirectory(base_dir)) {
+      NOTREACHED() << "Could not create SwReporter directory.";

[cpu_(ooo_6.6-7.5), 2014/06/18 01:58:36]

I would like to see a bunch of NOTREACHED gone and instead the set of UMA values
expanded to conver these cases. If you agree please review all of them in this
file.

[MAD, 2014/06/18 14:49:53]

Done.

+      return;
+    }
+  }
+
+  base::FilePath latest_version_path;
+  Version latest_version(kNullVersion);

[cpu_(ooo_6.6-7.5), 2014/06/18 01:58:36]

this is the only use of kNullVersion, feel free to remove the constant up there.
Its a nit anyhow.

[MAD, 2014/06/18 14:49:53]

Done.

+  std::vector<base::FilePath> older_dirs;
+  if (!GetLatestSwReporterDirectory(
+          &latest_version_path, &latest_version, &older_dirs)) {
+    BrowserThread::PostTask(
+        BrowserThread::UI,
+        FROM_HERE,
+        base::Bind(&RegisterSwReporterComponent, cus, latest_version, prefs));
+  } else {
+    BrowserThread::PostTask(
+        BrowserThread::UI,
+        FROM_HERE,
+        base::Bind(&MaybeExecuteReporter, latest_version_path, prefs));
+  }
+  // Remove older versions of SwReporter.

[cpu_(ooo_6.6-7.5), 2014/06/18 01:58:36]

Consider firing this deletion on the threadpool or in the file thread with a
delay, you can for example attempt to remove only one older version.

In other words this function has too many responsibilities. Definitely executing
is only one of them.

[MAD, 2014/06/18 14:49:53]

This code is gone now..

Note that this was inpired from the code that updates the SwiftShader component,
I wonder if the SiwftShader component should be fixed?

+  for (std::vector<base::FilePath>::iterator iter = older_dirs.begin();
+       iter != older_dirs.end();
+       ++iter) {
+    base::DeleteFile(*iter, true);

[cpu_(ooo_6.6-7.5), 2014/06/18 01:58:36]

funny enough, this delete is probably going to fail more often than the other
notreached or logged ones.

[MAD, 2014/06/18 14:49:53]

That code is gone now...

+  }
+}
+
+}  // namespace
+
+void ExecuteSwReporterComponent(ComponentUpdateService* cus,
+                                PrefService* prefs) {
+  int tries = prefs->GetInteger(prefs::kSwReporterComponentRegisterTryCount);
+  if (tries > kMaxRetry) {
+    ReportSwReporterStep(SW_REPORTER_RETRIED_TOO_MANY_DOWNLOADS);
+    // Let's forget about this attempt.
+    prefs->SetInteger(prefs::kSwReporterComponentRegisterTryCount, 0);
+    return;
+  }

[cpu_(ooo_6.6-7.5), 2014/06/18 01:58:36]

I am confused about the usage of Maybe in the function names, like this one
seems to not execute anything in 328.

If maybe remove the maybes since many of them maybe don't do the deed or maybe
you want to be maybe-consistent. I mean many chrome functions are in the maybe
category but we don't name them like that.

[MAD, 2014/06/18 14:49:53]

Done.

+
+  ReportSwReporterStep(tries ? SW_REPORTER_RETRYING_DOWNLOAD
+                             : SW_REPORTER_START_DOWNLOAD);
+  prefs->SetInteger(prefs::kSwReporterComponentRegisterTryCount, tries + 1);
+  BrowserThread::PostTask(
+      BrowserThread::FILE,
+      FROM_HERE,
+      base::Bind(&ExecuteSwReporterComponentOnFileThread, cus, prefs));
+}
+
+void MaybeExecuteSwReporterComponent(ComponentUpdateService* cus,
+                                     PrefService* prefs) {
+  // Only register if we have a pending registration / execution.
+  if (prefs->GetInteger(prefs::kSwReporterComponentRegisterTryCount) == 0) {
+    if (prefs->GetInteger(prefs::kSwReporterComponentExecuteTryCount) == 0)
+      return;
+    // We have a pending execution, let's check if it completed or not.
+    base::win::RegKey srt_key(
+        HKEY_CURRENT_USER, kSoftwareRemovalToolRegistryKey, KEY_READ);
+    DWORD exit_code = -1;
+    if (srt_key.Valid() &&
+        srt_key.ReadValueDW(kExitCodeRegistryValueName, &exit_code) ==
+            ERROR_SUCCESS) {
+      ReportAndClearSwReporterExitCode(exit_code);
+      return;
+    }
+
+    // If it didn't complete, let's make sure we didn't go beyond the maximum
+    // retry count yet.
+    if (prefs->GetInteger(prefs::kSwReporterComponentExecuteTryCount) >
+        kMaxRetry) {
+      ReportSwReporterStep(SW_REPORTER_RETRIED_TOO_MANY_EXECUTIONS);
+      // Let's forget about this attempt.
+      prefs->SetInteger(prefs::kSwReporterComponentExecuteTryCount, 0);
+      return;
+    }
+  }
+
+  ExecuteSwReporterComponent(cus, prefs);
+}
+
+void RegisterPrefsForSwReporterComponent(PrefRegistrySimple* registry) {
+  registry->RegisterIntegerPref(prefs::kSwReporterComponentRegisterTryCount, 0);
+  registry->RegisterIntegerPref(prefs::kSwReporterComponentExecuteTryCount, 0);
+}
+
+}  // namespace component_updater