Home | History | Annotate | Download | only in app 
      1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #include <windows.h>
      6 #include <shlwapi.h>
      7 
      8 #include "base/command_line.h"
      9 #include "base/compiler_specific.h"
     10 #include "base/debug/trace_event.h"
     11 #include "base/environment.h"
     12 #include "base/file_version_info.h"
     13 #include "base/lazy_instance.h"
     14 #include "base/logging.h"
     15 #include "base/memory/scoped_ptr.h"
     16 #include "base/rand_util.h"  // For PreRead experiment.
     17 #include "base/sha1.h"  // For PreRead experiment.
     18 #include "base/strings/string16.h"
     19 #include "base/strings/string_util.h"
     20 #include "base/strings/stringprintf.h"
     21 #include "base/strings/utf_string_conversions.h"
     22 #include "base/version.h"
     23 #include "base/win/windows_version.h"
     24 #include "chrome/app/chrome_breakpad_client.h"
     25 #include "chrome/app/client_util.h"
     26 #include "chrome/app/image_pre_reader_win.h"
     27 #include "chrome/common/chrome_constants.h"
     28 #include "chrome/common/chrome_result_codes.h"
     29 #include "chrome/common/chrome_switches.h"
     30 #include "chrome/common/env_vars.h"
     31 #include "chrome/installer/util/google_update_constants.h"
     32 #include "chrome/installer/util/google_update_settings.h"
     33 #include "chrome/installer/util/install_util.h"
     34 #include "chrome/installer/util/util_constants.h"
     35 #include "components/breakpad/app/breakpad_client.h"
     36 #include "components/breakpad/app/breakpad_win.h"
     37 #include "content/public/app/startup_helper_win.h"
     38 #include "sandbox/win/src/sandbox.h"
     39 
     40 namespace {
     41 // The entry point signature of chrome.dll.
     42 typedef int (*DLL_MAIN)(HINSTANCE, sandbox::SandboxInterfaceInfo*);
     43 
     44 typedef void (*RelaunchChromeBrowserWithNewCommandLineIfNeededFunc)();
     45 
     46 base::LazyInstance<chrome::ChromeBreakpadClient>::Leaky
     47     g_chrome_breakpad_client = LAZY_INSTANCE_INITIALIZER;
     48 
     49 // Returns true if the build date for this module precedes the expiry date
     50 // for the pre-read experiment.
     51 bool PreReadExperimentIsActive() {
     52   const int kPreReadExpiryYear = 2014;
     53   const int kPreReadExpiryMonth = 7;
     54   const int kPreReadExpiryDay = 1;
     55   const char kBuildTimeStr[] = __DATE__ " " __TIME__;
     56 
     57   // Get the timestamp of the build.
     58   base::Time build_time;
     59   bool result = base::Time::FromString(kBuildTimeStr, &build_time);
     60   DCHECK(result);
     61 
     62   // Get the timestamp at which the experiment expires.
     63   base::Time::Exploded exploded = {0};
     64   exploded.year = kPreReadExpiryYear;
     65   exploded.month = kPreReadExpiryMonth;
     66   exploded.day_of_month = kPreReadExpiryDay;
     67   base::Time expiration_time = base::Time::FromLocalExploded(exploded);
     68 
     69   // Return true if the build time predates the expiration time..
     70   return build_time < expiration_time;
     71 }
     72 
     73 // Get random unit values, i.e., in the range (0, 1), denoting a die-toss for
     74 // being in an experiment population and experimental group thereof.
     75 void GetPreReadPopulationAndGroup(double* population, double* group) {
     76   // By default we use the metrics id for the user as stable pseudo-random
     77   // input to a hash.
     78   std::string metrics_id;
     79   GoogleUpdateSettings::GetMetricsId(&metrics_id);
     80 
     81   // If this user has not metrics id, we fall back to a purely random value
     82   // per browser session.
     83   const size_t kLength = 16;
     84   std::string random_value(metrics_id.empty() ? base::RandBytesAsString(kLength)
     85                                               : metrics_id);
     86 
     87   // To interpret the value as a random number we hash it and read the first 8
     88   // bytes of the hash as a unit-interval representing a die-toss for being in
     89   // the experiment population and the second 8 bytes as a die-toss for being
     90   // in various experiment groups.
     91   unsigned char sha1_hash[base::kSHA1Length];
     92   base::SHA1HashBytes(
     93       reinterpret_cast<const unsigned char*>(random_value.c_str()),
     94       random_value.size() * sizeof(random_value[0]),
     95       sha1_hash);
     96   COMPILE_ASSERT(2 * sizeof(uint64) < sizeof(sha1_hash), need_more_data);
     97   const uint64* random_bits = reinterpret_cast<uint64*>(&sha1_hash[0]);
     98 
     99   // Convert the bits into unit-intervals and return.
    100   *population = base::BitsToOpenEndedUnitInterval(random_bits[0]);
    101   *group = base::BitsToOpenEndedUnitInterval(random_bits[1]);
    102 }
    103 
    104 // Gets the amount of pre-read to use as well as the experiment group in which
    105 // the user falls.
    106 size_t InitPreReadPercentage() {
    107   // By default use the old behaviour: read 100%.
    108   const int kDefaultPercentage = 100;
    109   const char kDefaultFormatStr[] = "%d-pct-default";
    110   const char kControlFormatStr[] = "%d-pct-control";
    111   const char kGroupFormatStr[] = "%d-pct";
    112 
    113   COMPILE_ASSERT(kDefaultPercentage <= 100, default_percentage_too_large);
    114   COMPILE_ASSERT(kDefaultPercentage % 5 == 0, default_percentage_not_mult_5);
    115 
    116   // Roll the dice to determine if this user is in the experiment and if so,
    117   // in which experimental group.
    118   double population = 0.0;
    119   double group = 0.0;
    120   GetPreReadPopulationAndGroup(&population, &group);
    121 
    122   // We limit experiment populations to 1% of the Stable and 10% of each of
    123   // the other channels.
    124   const base::string16 channel(GoogleUpdateSettings::GetChromeChannel(
    125       GoogleUpdateSettings::IsSystemInstall()));
    126   double threshold = (channel == installer::kChromeChannelStable) ? 0.01 : 0.10;
    127 
    128   // If the experiment has expired use the default pre-read level. Otherwise,
    129   // those not in the experiment population also use the default pre-read level.
    130   size_t value = kDefaultPercentage;
    131   const char* format_str = kDefaultFormatStr;
    132   if (PreReadExperimentIsActive() && (population <= threshold)) {
    133     // We divide the experiment population into groups pre-reading at 5 percent
    134     // increments in the range [0, 100].
    135     value = static_cast<size_t>(group * 21.0) * 5;
    136     DCHECK_LE(value, 100u);
    137     DCHECK_EQ(0u, value % 5);
    138     format_str =
    139         (value == kDefaultPercentage) ? kControlFormatStr : kGroupFormatStr;
    140   }
    141 
    142   // Generate the group name corresponding to this percentage value.
    143   std::string group_name;
    144   base::SStringPrintf(&group_name, format_str, value);
    145 
    146   // Persist the group name to the environment so that it can be used for
    147   // reporting.
    148   scoped_ptr<base::Environment> env(base::Environment::Create());
    149   env->SetVar(chrome::kPreReadEnvironmentVariable, group_name);
    150 
    151   // Return the percentage value to be used.
    152   return value;
    153 }
    154 
    155 // Expects that |dir| has a trailing backslash. |dir| is modified so it
    156 // contains the full path that was tried. Caller must check for the return
    157 // value not being null to determine if this path contains a valid dll.
    158 HMODULE LoadModuleWithDirectory(base::string16* dir,
    159                                 const wchar_t* dll_name,
    160                                 bool pre_read) {
    161   ::SetCurrentDirectoryW(dir->c_str());
    162   dir->append(dll_name);
    163 
    164   if (pre_read) {
    165 #if !defined(WIN_DISABLE_PREREAD)
    166     // We pre-read the binary to warm the memory caches (fewer hard faults to
    167     // page parts of the binary in).
    168     const size_t kStepSize = 1024 * 1024;
    169     size_t percentage = InitPreReadPercentage();
    170     ImagePreReader::PartialPreReadImage(dir->c_str(), percentage, kStepSize);
    171 #endif
    172   }
    173 
    174   return ::LoadLibraryExW(dir->c_str(), NULL,
    175                           LOAD_WITH_ALTERED_SEARCH_PATH);
    176 }
    177 
    178 void RecordDidRun(const base::string16& dll_path) {
    179   bool system_level = !InstallUtil::IsPerUserInstall(dll_path.c_str());
    180   GoogleUpdateSettings::UpdateDidRunState(true, system_level);
    181 }
    182 
    183 void ClearDidRun(const base::string16& dll_path) {
    184   bool system_level = !InstallUtil::IsPerUserInstall(dll_path.c_str());
    185   GoogleUpdateSettings::UpdateDidRunState(false, system_level);
    186 }
    187 
    188 bool InMetroMode() {
    189   return (wcsstr(
    190       ::GetCommandLineW(), L" -ServerName:DefaultBrowserServer") != NULL);
    191 }
    192 
    193 typedef int (*InitMetro)();
    194 
    195 }  // namespace
    196 
    197 base::string16 GetExecutablePath() {
    198   wchar_t path[MAX_PATH];
    199   ::GetModuleFileNameW(NULL, path, MAX_PATH);
    200   if (!::PathRemoveFileSpecW(path))
    201     return base::string16();
    202   base::string16 exe_path(path);
    203   return exe_path.append(1, L'\\');
    204 }
    205 
    206 base::string16 GetCurrentModuleVersion() {
    207   scoped_ptr<FileVersionInfo> file_version_info(
    208       FileVersionInfo::CreateFileVersionInfoForCurrentModule());
    209   if (file_version_info.get()) {
    210     base::string16 version_string(file_version_info->file_version());
    211     if (Version(base::UTF16ToASCII(version_string)).IsValid())
    212       return version_string;
    213   }
    214   return base::string16();
    215 }
    216 
    217 //=============================================================================
    218 
    219 MainDllLoader::MainDllLoader()
    220   : dll_(NULL), metro_mode_(InMetroMode()) {
    221 }
    222 
    223 MainDllLoader::~MainDllLoader() {
    224 }
    225 
    226 // Loading chrome is an interesting affair. First we try loading from the
    227 // current directory to support run-what-you-compile and other development
    228 // scenarios.
    229 // If that fails then we look at the version resource in the current
    230 // module. This is the expected path for chrome.exe browser instances in an
    231 // installed build.
    232 HMODULE MainDllLoader::Load(base::string16* version,
    233                             base::string16* out_file) {
    234   const base::string16 executable_dir(GetExecutablePath());
    235   *out_file = executable_dir;
    236 
    237   const wchar_t* dll_name = metro_mode_ ?
    238       installer::kChromeMetroDll :
    239 #if !defined(CHROME_MULTIPLE_DLL)
    240       installer::kChromeDll;
    241 #else
    242       (process_type_ == "service")  || process_type_.empty() ?
    243           installer::kChromeDll :
    244           installer::kChromeChildDll;
    245 #endif
    246   const bool pre_read = !metro_mode_;
    247   HMODULE dll = LoadModuleWithDirectory(out_file, dll_name, pre_read);
    248   if (!dll) {
    249     base::string16 version_string(GetCurrentModuleVersion());
    250     if (version_string.empty()) {
    251       LOG(ERROR) << "No valid Chrome version found";
    252       return NULL;
    253     }
    254     *out_file = executable_dir;
    255     *version = version_string;
    256     out_file->append(version_string).append(1, L'\\');
    257     dll = LoadModuleWithDirectory(out_file, dll_name, pre_read);
    258     if (!dll) {
    259       PLOG(ERROR) << "Failed to load Chrome DLL from " << *out_file;
    260       return NULL;
    261     }
    262   }
    263 
    264   DCHECK(dll);
    265   return dll;
    266 }
    267 
    268 // Launching is a matter of loading the right dll, setting the CHROME_VERSION
    269 // environment variable and just calling the entry point. Derived classes can
    270 // add custom code in the OnBeforeLaunch callback.
    271 int MainDllLoader::Launch(HINSTANCE instance) {
    272   const CommandLine& cmd_line = *CommandLine::ForCurrentProcess();
    273   process_type_ = cmd_line.GetSwitchValueASCII(switches::kProcessType);
    274 
    275   base::string16 version;
    276   base::string16 file;
    277 
    278   if (metro_mode_) {
    279     HMODULE metro_dll = Load(&version, &file);
    280     if (!metro_dll)
    281       return chrome::RESULT_CODE_MISSING_DATA;
    282 
    283     InitMetro chrome_metro_main =
    284         reinterpret_cast<InitMetro>(::GetProcAddress(metro_dll, "InitMetro"));
    285     return chrome_metro_main();
    286   }
    287 
    288   // Initialize the sandbox services.
    289   sandbox::SandboxInterfaceInfo sandbox_info = {0};
    290   content::InitializeSandboxInfo(&sandbox_info);
    291 
    292   breakpad::SetBreakpadClient(g_chrome_breakpad_client.Pointer());
    293   bool exit_now = true;
    294   if (process_type_.empty()) {
    295     if (breakpad::ShowRestartDialogIfCrashed(&exit_now)) {
    296       // We restarted because of a previous crash. Ask user if we should
    297       // Relaunch. Only for the browser process. See crbug.com/132119.
    298       if (exit_now)
    299         return content::RESULT_CODE_NORMAL_EXIT;
    300     }
    301   }
    302   breakpad::InitCrashReporter(process_type_);
    303 
    304   dll_ = Load(&version, &file);
    305   if (!dll_)
    306     return chrome::RESULT_CODE_MISSING_DATA;
    307 
    308   scoped_ptr<base::Environment> env(base::Environment::Create());
    309   env->SetVar(chrome::kChromeVersionEnvVar, base::WideToUTF8(version));
    310 
    311   OnBeforeLaunch(file);
    312   DLL_MAIN chrome_main =
    313       reinterpret_cast<DLL_MAIN>(::GetProcAddress(dll_, "ChromeMain"));
    314   int rc = chrome_main(instance, &sandbox_info);
    315   return OnBeforeExit(rc, file);
    316 }
    317 
    318 void MainDllLoader::RelaunchChromeBrowserWithNewCommandLineIfNeeded() {
    319   if (!dll_)
    320     return;
    321 
    322   RelaunchChromeBrowserWithNewCommandLineIfNeededFunc relaunch_function =
    323       reinterpret_cast<RelaunchChromeBrowserWithNewCommandLineIfNeededFunc>(
    324           ::GetProcAddress(dll_,
    325                            "RelaunchChromeBrowserWithNewCommandLineIfNeeded"));
    326   if (!relaunch_function) {
    327     LOG(ERROR) << "Could not find exported function "
    328                << "RelaunchChromeBrowserWithNewCommandLineIfNeeded";
    329   } else {
    330     relaunch_function();
    331   }
    332 }
    333 
    334 //=============================================================================
    335 
    336 class ChromeDllLoader : public MainDllLoader {
    337  protected:
    338   virtual void OnBeforeLaunch(const base::string16& dll_path) {
    339     RecordDidRun(dll_path);
    340   }
    341 
    342   virtual int OnBeforeExit(int return_code, const base::string16& dll_path) {
    343     // NORMAL_EXIT_CANCEL is used for experiments when the user cancels
    344     // so we need to reset the did_run signal so omaha does not count
    345     // this run as active usage.
    346     if (chrome::RESULT_CODE_NORMAL_EXIT_CANCEL == return_code) {
    347       ClearDidRun(dll_path);
    348     }
    349     return return_code;
    350   }
    351 };
    352 
    353 //=============================================================================
    354 
    355 class ChromiumDllLoader : public MainDllLoader {
    356  protected:
    357   virtual void OnBeforeLaunch(const base::string16& dll_path) OVERRIDE {
    358   }
    359   virtual int OnBeforeExit(int return_code,
    360                            const base::string16& dll_path) OVERRIDE {
    361     return return_code;
    362   }
    363 };
    364 
    365 MainDllLoader* MakeMainDllLoader() {
    366 #if defined(GOOGLE_CHROME_BUILD)
    367   return new ChromeDllLoader();
    368 #else
    369   return new ChromiumDllLoader();
    370 #endif
    371 }
    372