Pulling user experiment code from BrowserDistribution to a new class.

chrome/installer/util/user_experiment.cc

+// Copyright 2013 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/installer/util/user_experiment.h"
+
+#include <sddl.h>
+#include <wtsapi32.h>
+#include <vector>
+
+#include "base/command_line.h"
+#include "base/file_path.h"
+#include "base/process_util.h"
+#include "base/rand_util.h"
+#include "base/string_split.h"
+#include "base/string_util.h"
+#include "base/strings/string_number_conversions.h"
+#include "base/utf_string_conversions.h"
+#include "base/version.h"
+#include "base/win/windows_version.h"
+#include "chrome/common/attrition_experiments.h"
+#include "chrome/common/chrome_result_codes.h"
+#include "chrome/common/chrome_switches.h"
+#include "chrome/installer/util/browser_distribution.h"
+#include "chrome/installer/util/google_update_constants.h"
+#include "chrome/installer/util/google_update_settings.h"
+#include "chrome/installer/util/install_util.h"
+#include "chrome/installer/util/product.h"
+#include "content/public/common/result_codes.h"
+
+#pragma comment(lib, "wtsapi32.lib")
+
+namespace installer {
+
+namespace {
+
+const wchar_t kChromeGuid[] = L"{8A69D345-D564-463c-AFF1-A69D9E530F96}";

[grt (UTC plus 2), 2013/02/22 16:47:56]

this and the next three constants appear to be unused.

[huangs, 2013/02/22 20:32:37]

Yes, missed a spot.  Deleted.

+const wchar_t kBrowserAppId[] = L"Chrome";
+const wchar_t kCommandExecuteImplUuid[] =
+    L"{5C65F4B0-3651-4514-B207-D10CB699B14B}";
+
+// The following strings are the possible outcomes of the toast experiment
+// as recorded in the |client| field.
+const wchar_t kToastExpControlGroup[] =        L"01";
+const wchar_t kToastExpCancelGroup[] =         L"02";
+const wchar_t kToastExpUninstallGroup[] =      L"04";
+const wchar_t kToastExpTriesOkGroup[] =        L"18";
+const wchar_t kToastExpTriesErrorGroup[] =     L"28";
+const wchar_t kToastActiveGroup[] =            L"40";
+const wchar_t kToastUDDirFailure[] =           L"40";
+const wchar_t kToastExpBaseGroup[] =           L"80";
+
+// Substitute the locale parameter in uninstall URL with whatever
+// Google Update tells us is the locale. In case we fail to find
+// the locale, we use US English.
+string16 LocalizeUrl(const wchar_t* url) {
+  string16 language;
+  if (!GoogleUpdateSettings::GetLanguage(&language))
+    language = L"en-US";  // Default to US English.
+  return ReplaceStringPlaceholders(url, language.c_str(), NULL);
+}
+
+string16 GetWelcomeBackUrl() {
+  const wchar_t kWelcomeUrl[] = L"http://www.google.com/chrome/intl/$1/"
+                                L"welcomeback-new.html";
+  return LocalizeUrl(kWelcomeUrl);
+}
+
+// Converts FILETIME to hours. FILETIME times are absolute times in
+// 100 nanosecond units. For example 5:30 pm of June 15, 2009 is 3580464.
+int FileTimeToHours(const FILETIME& time) {
+  const ULONGLONG k100sNanoSecsToHours = 10000000LL * 60 * 60;
+  ULARGE_INTEGER uli = {time.dwLowDateTime, time.dwHighDateTime};
+  return static_cast<int>(uli.QuadPart / k100sNanoSecsToHours);
+}
+
+// Returns the directory last write time in hours since January 1, 1601.
+// Returns -1 if there was an error retrieving the directory time.
+int GetDirectoryWriteTimeInHours(const wchar_t* path) {
+  // To open a directory you need to pass FILE_FLAG_BACKUP_SEMANTICS.
+  DWORD share = FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE;
+  HANDLE file = ::CreateFileW(path, 0, share, NULL, OPEN_EXISTING,

[grt (UTC plus 2), 2013/02/22 16:47:56]

use base::win::ScopedHandle and remove calls to CloseHandle below

[huangs, 2013/02/22 20:32:37]

Done.

+                              FILE_FLAG_BACKUP_SEMANTICS, NULL);
+  if (INVALID_HANDLE_VALUE == file)
+    return -1;
+  FILETIME time;
+  if (!::GetFileTime(file, NULL, NULL, &time)) {
+    ::CloseHandle(file);
+    return -1;
+  }
+
+  ::CloseHandle(file);
+  return FileTimeToHours(time);
+}
+
+// Returns the directory last-write time age in hours, relative to current
+// time, so if it returns 14 it means that the directory was last written 14
+// hours ago. Returns -1 if there was an error retrieving the directory.
+int GetDirectoryWriteAgeInHours(const wchar_t* path) {
+  int dir_time = GetDirectoryWriteTimeInHours(path);
+  if (dir_time < 0)
+    return dir_time;
+  FILETIME time;
+  GetSystemTimeAsFileTime(&time);
+  int now_time = FileTimeToHours(time);
+  if (dir_time >= now_time)
+    return 0;
+  return (now_time - dir_time);
+}
+
+// Launches setup.exe (located at |setup_path|) with |cmd_line|.
+// If system_level_toast is true, appends --system-level-toast.
+// If handle to experiment result key was given at startup, re-add it.
+// Does not wait for the process to terminate.
+// |cmd_line| may be modified as a result of this call.
+bool LaunchSetup(CommandLine* cmd_line,
+                 const installer::Product& product,
+                 bool system_level_toast) {
+  const CommandLine& current_cmd_line = *CommandLine::ForCurrentProcess();
+
+  // Propagate --verbose-logging to the invoked setup.exe.
+  if (current_cmd_line.HasSwitch(installer::switches::kVerboseLogging))
+    cmd_line->AppendSwitch(installer::switches::kVerboseLogging);
+
+  // Pass along product-specific options.
+  product.AppendProductFlags(cmd_line);
+
+  // Re-add the system level toast flag.
+  if (system_level_toast) {
+    cmd_line->AppendSwitch(installer::switches::kSystemLevel);
+    cmd_line->AppendSwitch(installer::switches::kSystemLevelToast);
+
+    // Re-add the toast result key. We need to do this because Setup running as
+    // system passes the key to Setup running as user, but that child process
+    // does not perform the actual toasting, it launches another Setup (as user)
+    // to do so. That is the process that needs the key.
+    std::string key(installer::switches::kToastResultsKey);
+    std::string toast_key = current_cmd_line.GetSwitchValueASCII(key);
+    if (!toast_key.empty()) {
+      cmd_line->AppendSwitchASCII(key, toast_key);
+
+      // Use handle inheritance to make sure the duplicated toast results key
+      // gets inherited by the child process.
+      base::LaunchOptions options;
+      options.inherit_handles = true;
+      return base::LaunchProcess(*cmd_line, options, NULL);
+    }
+  }
+
+  return base::LaunchProcess(*cmd_line, base::LaunchOptions(), NULL);
+}
+
+// For System level installs, setup.exe lives in the system temp, which
+// is normally c:\windows\temp. In many cases files inside this folder
+// are not accessible for execution by regular user accounts.
+// This function changes the permissions so that any authenticated user
+// can launch |exe| later on. This function should only be called if the
+// code is running at the system level.
+bool FixDACLsForExecute(const base::FilePath& exe) {
+  // The general strategy to is to add an ACE to the exe DACL the quick
+  // and dirty way: a) read the DACL b) convert it to sddl string c) add the
+  // new ACE to the string d) convert sddl string back to DACL and finally
+  // e) write new dacl.
+  char buff[1024];
+  DWORD len = sizeof(buff);
+  PSECURITY_DESCRIPTOR sd = reinterpret_cast<PSECURITY_DESCRIPTOR>(buff);
+  if (!::GetFileSecurityW(exe.value().c_str(), DACL_SECURITY_INFORMATION,
+                          sd, len, &len)) {
+    return false;
+  }
+  wchar_t* sddl = 0;
+  if (!::ConvertSecurityDescriptorToStringSecurityDescriptorW(sd,
+      SDDL_REVISION_1, DACL_SECURITY_INFORMATION, &sddl, NULL))
+    return false;
+  string16 new_sddl(sddl);
+  ::LocalFree(sddl);
+  sd = NULL;
+  // See MSDN for the  security descriptor definition language (SDDL) syntax,
+  // in our case we add "A;" generic read 'GR' and generic execute 'GX' for
+  // the nt\authenticated_users 'AU' group, that becomes:
+  const wchar_t kAllowACE[] = L"(A;;GRGX;;;AU)";
+  // We should check that there are no special ACES for the group we
+  // are interested, which is nt\authenticated_users.
+  if (string16::npos != new_sddl.find(L";AU)"))
+    return false;
+  // Specific ACEs (not inherited) need to go to the front. It is ok if we
+  // are the very first one.
+  size_t pos_insert = new_sddl.find(L"(");
+  if (string16::npos == pos_insert)
+    return false;
+  // All good, time to change the dacl.
+  new_sddl.insert(pos_insert, kAllowACE);
+  if (!::ConvertStringSecurityDescriptorToSecurityDescriptorW(new_sddl.c_str(),
+      SDDL_REVISION_1, &sd, NULL))
+    return false;
+  bool rv = ::SetFileSecurityW(exe.value().c_str(), DACL_SECURITY_INFORMATION,
+                               sd) == TRUE;
+  ::LocalFree(sd);
+  return rv;
+}
+
+// This function launches setup as the currently logged-in interactive
+// user that is the user whose logon session is attached to winsta0\default.
+// It assumes that currently we are running as SYSTEM in a non-interactive
+// windowstation.
+// The function fails if there is no interactive session active, basically
+// the computer is on but nobody has logged in locally.
+// Remote Desktop sessions do not count as interactive sessions; running this
+// method as a user logged in via remote desktop will do nothing.
+bool LaunchSetupAsConsoleUser(const base::FilePath& setup_path,
+                              const installer::Product& product,
+                              const std::string& flag) {
+  CommandLine cmd_line(setup_path);
+  cmd_line.AppendSwitch(flag);
+
+  // Pass along product-specific options.
+  product.AppendProductFlags(&cmd_line);
+
+  // Convey to the invoked setup.exe that it's operating on a system-level
+  // installation.
+  cmd_line.AppendSwitch(installer::switches::kSystemLevel);
+
+  // Propagate --verbose-logging to the invoked setup.exe.
+  if (CommandLine::ForCurrentProcess()->HasSwitch(
+          installer::switches::kVerboseLogging)) {
+    cmd_line.AppendSwitch(installer::switches::kVerboseLogging);
+  }
+
+  // Get the Google Update results key, and pass it on the command line to
+  // the child process.
+  int key = GoogleUpdateSettings::DuplicateGoogleUpdateSystemClientKey();
+  cmd_line.AppendSwitchASCII(installer::switches::kToastResultsKey,
+                             base::IntToString(key));
+
+  if (base::win::GetVersion() > base::win::VERSION_XP) {
+    // Make sure that in Vista and Above we have the proper DACLs so
+    // the interactive user can launch it.
+    if (!FixDACLsForExecute(setup_path))
+      NOTREACHED();
+  }
+
+  DWORD console_id = ::WTSGetActiveConsoleSessionId();
+  if (console_id == 0xFFFFFFFF) {
+    PLOG(ERROR) << __FUNCTION__ << " failed to get active session id";
+    return false;
+  }
+  HANDLE user_token;
+  if (!::WTSQueryUserToken(console_id, &user_token)) {
+    PLOG(ERROR) << __FUNCTION__ << " failed to get user token for console_id "
+                << console_id;
+    return false;
+  }
+  // Note: Handle inheritance must be true in order for the child process to be
+  // able to use the duplicated handle above (Google Update results).
+  base::LaunchOptions options;
+  options.as_user = user_token;
+  options.inherit_handles = true;
+  options.empty_desktop_name = true;
+  VLOG(1) << __FUNCTION__ << " launching " << cmd_line.GetCommandLineString();
+  bool launched = base::LaunchProcess(cmd_line, options, NULL);
+  ::CloseHandle(user_token);
+  VLOG(1) << __FUNCTION__ << "   result: " << launched;
+  return launched;
+}
+
+// A helper function that writes to HKLM if the handle was passed through the
+// command line, but HKCU otherwise. |experiment_group| is the value to write
+// and |last_write| is used when writing to HKLM to determine whether to close
+// the handle when done.
+void SetClient(const string16& experiment_group, bool last_write) {
+  static int reg_key_handle = -1;
+  if (reg_key_handle == -1) {
+    // If a specific Toast Results key handle (presumably to our HKLM key) was
+    // passed in to the command line (such as for system level installs), we use
+    // it. Otherwise, we write to the key under HKCU.
+    const CommandLine& cmd_line = *CommandLine::ForCurrentProcess();
+    if (cmd_line.HasSwitch(installer::switches::kToastResultsKey)) {
+      // Get the handle to the key under HKLM.
+      base::StringToInt(cmd_line.GetSwitchValueASCII(
+          installer::switches::kToastResultsKey).c_str(),
+          &reg_key_handle);
+    } else {
+      reg_key_handle = 0;
+    }
+  }
+
+  if (reg_key_handle) {
+    // Use it to write the experiment results.
+    GoogleUpdateSettings::WriteGoogleUpdateSystemClientKey(
+        reg_key_handle, google_update::kRegClientField, experiment_group);
+    if (last_write)
+      CloseHandle((HANDLE) reg_key_handle);
+  } else {
+    // Write to HKCU.
+    GoogleUpdateSettings::SetClient(experiment_group);
+  }
+}
+
+}  // namespace
+
+UserExperiment::UserExperiment() {}
+
+// static
+bool UserExperiment::CreateExperimentDetails(
+    UserExperiment::ExperimentDetails* experiment,
+    int flavor) {
+  struct FlavorDetails {
+    int heading_id;
+    int flags;
+  };
+  // Maximum number of experiment flavors we support.
+  static const int kMax = 4;
+  // This struct determines which experiment flavors we show for each locale and
+  // brand.
+  //
+  // Plugin infobar experiment:
+  // The experiment in 2011 used PIxx codes.
+  //
+  // Inactive user toast experiment:
+  // The experiment in Dec 2009 used TGxx and THxx.
+  // The experiment in Feb 2010 used TKxx and TLxx.
+  // The experiment in Apr 2010 used TMxx and TNxx.
+  // The experiment in Oct 2010 used TVxx TWxx TXxx TYxx.
+  // The experiment in Feb 2011 used SJxx SKxx SLxx SMxx.
+  // The experiment in Mar 2012 used ZAxx ZBxx ZCxx.
+  // The experiment in Jan 2013 uses DAxx.
+  using namespace attrition_experiments;
+
+  static const struct UserExperimentSpecs {
+    const wchar_t* locale;  // Locale to show this experiment for (* for all).
+    const wchar_t* brands;  // Brand codes show this experiment for (* for all).
+    int control_group;      // Size of the control group, in percentages.
+    const wchar_t* prefix;  // The two letter experiment code. The second letter
+                            // will be incremented with the flavor.
+    FlavorDetails flavors[kMax];
+  } kExperiments[] = {
+    // The first match from top to bottom is used so this list should be ordered
+    // most-specific rule first.
+    { L"*", L"GGRV",  // All locales, GGRV is enterprise.
+      0,              // 0 percent control group.
+      L"EA",          // Experiment is EAxx, EBxx, etc.
+      // No flavors means no experiment.
+      { { 0, 0 },
+        { 0, 0 },
+        { 0, 0 },
+        { 0, 0 }
+      }
+    },
+    { L"*", L"*",     // All locales, all brands.
+      5,              // 5 percent control group.
+      L"DA",          // Experiment is DAxx.
+      // One single flavor.
+      { { IDS_TRY_TOAST_HEADING3, kMakeDefault },
+        { 0, 0 },
+        { 0, 0 },
+        { 0, 0 }
+      }
+    }
+  };
+
+  string16 locale;
+  GoogleUpdateSettings::GetLanguage(&locale);
+  if (locale.empty() || (locale == ASCIIToWide("en")))
+    locale = ASCIIToWide("en-US");
+
+  string16 brand;
+  if (!GoogleUpdateSettings::GetBrand(&brand))
+    brand = ASCIIToWide("");  // Could still be viable for catch-all rules.
+
+  for (int i = 0; i < arraysize(kExperiments); ++i) {
+    if (kExperiments[i].locale != locale &&
+        kExperiments[i].locale != ASCIIToWide("*"))
+      continue;
+
+    std::vector<string16> brand_codes;
+    base::SplitString(kExperiments[i].brands, L',', &brand_codes);
+    if (brand_codes.empty())
+      return false;
+    for (std::vector<string16>::iterator it = brand_codes.begin();
+         it != brand_codes.end(); ++it) {
+      if (*it != brand && *it != L"*")
+        continue;
+      // We have found our match.
+      const UserExperimentSpecs& match = kExperiments[i];
+      // Find out how many flavors we have. Zero means no experiment.
+      int num_flavors = 0;
+      while (match.flavors[num_flavors].heading_id) { ++num_flavors; }
+      if (!num_flavors)
+        return false;
+
+      if (flavor < 0)
+        flavor = base::RandInt(0, num_flavors - 1);
+      experiment->flavor = flavor;
+      experiment->heading = match.flavors[flavor].heading_id;
+      experiment->control_group = match.control_group;
+      const wchar_t prefix[] = { match.prefix[0], match.prefix[1] + flavor, 0 };
+      experiment->prefix = prefix;
+      experiment->flags = match.flavors[flavor].flags;
+      return true;
+    }
+  }
+
+  return false;
+}
+
+// Currently we only have one experiment: the inactive user toast. Which only
+// applies for users doing upgrades.
+
+// static
+// There are three scenarios when this function is called:
+// 1- Is a per-user-install and it updated: perform the experiment
+// 2- Is a system-install and it updated : relaunch as the interactive user
+// 3- It has been re-launched from the #2 case. In this case we enter
+//    this function with |system_install| true and a REENTRY_SYS_UPDATE status.
+void UserExperiment::LaunchUserExperiment(const base::FilePath& setup_path,
+                                          installer::InstallStatus status,
+                                          const Version& version,
+                                          const installer::Product& product,
+                                          bool system_level) {
+  VLOG(1) << "LaunchUserExperiment status: " << status << " product: "
+          << product.distribution()->GetAppShortCutName()
+          << " system_level: " << system_level;
+
+  if (system_level) {
+    if (installer::NEW_VERSION_UPDATED == status) {
+      // We need to relaunch as the interactive user.
+      LaunchSetupAsConsoleUser(setup_path, product,
+                               installer::switches::kSystemLevelToast);
+      return;
+    }
+  } else {
+    if ((installer::NEW_VERSION_UPDATED != status) &&
+        (installer::REENTRY_SYS_UPDATE != status)) {
+      // We are not updating or in re-launch. Exit.
+      return;
+    }
+  }
+
+  // The |flavor| value ends up being processed by TryChromeDialogView to show
+  // different experiments.
+  ExperimentDetails experiment;
+  if (!CreateExperimentDetails(&experiment, -1)) {
+    VLOG(1) << "Failed to get experiment details.";
+    return;
+  }
+  int flavor = experiment.flavor;
+  string16 base_group = experiment.prefix;
+
+  string16 brand;
+  if (GoogleUpdateSettings::GetBrand(&brand) && (brand == L"CHXX")) {
+    // Testing only: the user automatically qualifies for the experiment.
+    VLOG(1) << "Experiment qualification bypass";
+  } else {
+    // Check that the user was not already drafted in this experiment.
+    string16 client;
+    GoogleUpdateSettings::GetClient(&client);
+    if (client.size() > 2) {
+      if (base_group == client.substr(0, 2)) {
+        VLOG(1) << "User already participated in this experiment";
+        return;
+      }
+    }
+    // Check browser usage inactivity by the age of the last-write time of the
+    // most recently-used chrome user data directory.
+    std::vector<base::FilePath> user_data_dirs;
+    product.GetUserDataPaths(&user_data_dirs);
+    int dir_age_hours = -1;
+    for (size_t i = 0; i < user_data_dirs.size(); ++i) {
+      int this_age = GetDirectoryWriteAgeInHours(
+          user_data_dirs[i].value().c_str());
+      if (this_age >= 0 && (dir_age_hours < 0 || this_age < dir_age_hours))
+        dir_age_hours = this_age;
+    }
+
+    const bool experiment_enabled = false;
+    const int kThirtyDays = 30 * 24;
+
+    if (!experiment_enabled) {
+      VLOG(1) << "Toast experiment is disabled.";
+      return;
+    } else if (dir_age_hours < 0) {
+      // This means that we failed to find the user data dir. The most likely
+      // cause is that this user has not ever used chrome at all which can
+      // happen in a system-level install.
+      SetClient(base_group + kToastUDDirFailure, true);
+      return;
+    } else if (dir_age_hours < kThirtyDays) {
+      // An active user, so it does not qualify.
+      VLOG(1) << "Chrome used in last " << dir_age_hours << " hours";
+      SetClient(base_group + kToastActiveGroup, true);
+      return;
+    }
+    // Check to see if this user belongs to the control group.
+    double control_group = 1.0 * (100 - experiment.control_group) / 100;
+    if (base::RandDouble() > control_group) {
+      SetClient(base_group + kToastExpControlGroup, true);
+      VLOG(1) << "User is control group";
+      return;
+    }
+  }
+
+  VLOG(1) << "User drafted for toast experiment " << flavor;
+  SetClient(base_group + kToastExpBaseGroup, false);
+  // User level: The experiment needs to be performed in a different process
+  // because google_update expects the upgrade process to be quick and nimble.
+  // System level: We have already been relaunched, so we don't need to be
+  // quick, but we relaunch to follow the exact same codepath.
+  CommandLine cmd_line(setup_path);
+  cmd_line.AppendSwitchASCII(installer::switches::kInactiveUserToast,
+                             base::IntToString(flavor));
+  cmd_line.AppendSwitchASCII(installer::switches::kExperimentGroup,
+                             WideToASCII(base_group));
+  LaunchSetup(&cmd_line, product, system_level);
+}
+
+// static
+// User qualifies for the experiment. To test, use --try-chrome-again=|flavor|
+// as a parameter to chrome.exe.
+void UserExperiment::InactiveUserToastExperiment(
+    BrowserDistribution* dist,
+    int flavor,
+    const string16& experiment_group,
+    const installer::Product& installation,
+    const base::FilePath& application_path) {
+  // Add the 'welcome back' url for chrome to show.
+  CommandLine options(CommandLine::NO_PROGRAM);
+  options.AppendSwitchNative(::switches::kTryChromeAgain,
+      base::IntToString16(flavor));
+  // Prepend the url with a space.
+  string16 url(GetWelcomeBackUrl());
+  options.AppendArg("--");
+  options.AppendArgNative(url);
+  // The command line should now have the url added as:
+  // "chrome.exe -- <url>"
+  DCHECK_NE(string16::npos,
+      options.GetCommandLineString().find(L" -- " + url));
+
+  // Launch chrome now. It will show the toast UI.
+  int32 exit_code = 0;
+  if (!installation.LaunchChromeAndWait(application_path, options, &exit_code))
+    return;
+
+  // The chrome process has exited, figure out what happened.
+  const wchar_t* outcome = NULL;
+  switch (exit_code) {
+    case content::RESULT_CODE_NORMAL_EXIT:
+      outcome = kToastExpTriesOkGroup;
+      break;
+    case chrome::RESULT_CODE_NORMAL_EXIT_CANCEL:
+      outcome = kToastExpCancelGroup;
+      break;
+    case chrome::RESULT_CODE_NORMAL_EXIT_EXP2:
+      outcome = kToastExpUninstallGroup;
+      break;
+    default:
+      outcome = kToastExpTriesErrorGroup;
+  };
+  // Write to the |client| key for the last time.
+  SetClient(experiment_group + outcome, true);
+
+  if (outcome != kToastExpUninstallGroup)
+    return;
+  // The user wants to uninstall. This is a best effort operation. Note that
+  // we waited for chrome to exit so the uninstall would not detect chrome
+  // running.
+  bool system_level_toast = CommandLine::ForCurrentProcess()->HasSwitch(
+      installer::switches::kSystemLevelToast);
+
+  CommandLine cmd(InstallUtil::GetChromeUninstallCmd(system_level_toast,
+                                                     dist->GetType()));
+  base::LaunchProcess(cmd, base::LaunchOptions(), NULL);
+}
+
+}  // namespace installer