Make Crashpad use the user data dir, rather than always default location

chrome/install_static/policy_path_parser.cc

-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Copyright 2016 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/policy/policy_path_parser.h"
+#include "chrome/install_static/policy_path_parser.h"
 
 #include <shlobj.h>
 #include <stddef.h>
 #include <wtsapi32.h>
 
 #include <memory>
 
-#include "base/macros.h"
-#include "base/strings/utf_string_conversions.h"
-#include "base/win/registry.h"
-#include "chrome/common/chrome_switches.h"
-#include "components/policy/policy_constants.h"
-
 namespace {
 
-// Checks if the key exists in the given hive and expands any string variables.
-bool LoadUserDataDirPolicyFromRegistry(HKEY hive,
-                                       const char* key_name_str,
-                                       base::FilePath* dir) {
-  base::string16 value;
-  base::string16 key_name(base::ASCIIToUTF16(key_name_str));
-  base::win::RegKey key(hive, policy::kRegistryChromePolicyKey, KEY_READ);
-  if (key.ReadValue(key_name.c_str(), &value) == ERROR_SUCCESS) {
-    *dir = base::FilePath(policy::path_parser::ExpandPathVariables(value));
-    return true;
-  }
-  return false;
-}
-
 const WCHAR* kMachineNamePolicyVarName = L"${machine_name}";
 const WCHAR* kUserNamePolicyVarName = L"${user_name}";
 const WCHAR* kWinDocumentsFolderVarName = L"${documents}";
 const WCHAR* kWinLocalAppDataFolderVarName = L"${local_app_data}";
 const WCHAR* kWinRoamingAppDataFolderVarName = L"${roaming_app_data}";
 const WCHAR* kWinProfileFolderVarName = L"${profile}";
 const WCHAR* kWinProgramDataFolderVarName = L"${global_app_data}";
 const WCHAR* kWinProgramFilesFolderVarName = L"${program_files}";
 const WCHAR* kWinWindowsFolderVarName = L"${windows}";
 const WCHAR* kWinClientName = L"${client_name}";
@@ skipping 10 matching lines @@
     { kWinProgramFilesFolderVarName,   CSIDL_PROGRAM_FILES},
     { kWinProgramDataFolderVarName,    CSIDL_COMMON_APPDATA},
     { kWinProfileFolderVarName,        CSIDL_PROFILE},
     { kWinLocalAppDataFolderVarName,   CSIDL_LOCAL_APPDATA},
     { kWinRoamingAppDataFolderVarName, CSIDL_APPDATA},
     { kWinDocumentsFolderVarName,      CSIDL_PERSONAL}
 };
 
 }  // namespace
 
-namespace policy {
+namespace install_static {
 
-namespace path_parser {
+template <class T, size_t N>
+constexpr size_t arraysize(const T (&array)[N]) {

[grt (UTC plus 2), 2016/11/16 13:24:52]

use _countof from stdlib.h instead of this

[scottmg, 2016/11/16 21:01:18]

Done.

+  return N;
+}
 
 // Replaces all variable occurances in the policy string with the respective
 // system settings values.
-base::FilePath::StringType ExpandPathVariables(
-    const base::FilePath::StringType& untranslated_string) {
-  base::FilePath::StringType result(untranslated_string);
+// Note that this uses GetProcAddress to load DLLs that cannot be loaded before
+// the blacklist in the DllMain of chrome_elf has been applied. This function
+// should only be used after DllMain() has run.

[grt (UTC plus 2), 2016/11/16 13:24:52]

wdyt of adding something to enforce this? the first thing that comes to mind is
an "EnablePathExpansion();" call at the end of DllMain that sets some state that
is assert()ed on here.

[scottmg, 2016/11/16 21:01:18]

I think it's OK without that because it'll be pretty obvious because it'll
deadlock on the LoadLibrary().

+std::wstring ExpandPathVariables(
+    const std::wstring& untranslated_string) {
+  std::wstring result(untranslated_string);
   if (result.length() == 0)
     return result;
   // Sanitize quotes in case of any around the whole string.
   if (result.length() > 1 &&
       ((result.front() == L'"' && result.back() == L'"') ||
        (result.front() == L'\'' && result.back() == L'\''))) {
     // Strip first and last char which should be matching quotes now.
     result = result.substr(1, result.length() - 2);

[grt (UTC plus 2), 2016/11/16 13:24:52]

i would think that
    result.pop_back();
    result.erase(0, 1);
would be less wasteful. if you want to keep it on one line:
    result.erase(0, 1).pop_back();

[scottmg, 2016/11/16 21:01:18]

Maybe a little... I admit I only moved this code, I didn't read it.

   }
+  static auto sh_get_special_folder_path =
+      reinterpret_cast<decltype(::SHGetSpecialFolderPath)*>(GetProcAddress(
+          LoadLibrary(L"shell32.dll"), "SHGetSpecialFolderPathW"));

[grt (UTC plus 2), 2016/11/16 13:24:52]

no matching calls to FreeLibrary for any of these. is this intentional? it seems
bad.

[scottmg, 2016/11/16 21:01:18]

I thought about that. But cpu@ always implied unloading a DLL was like casting a
hex on yourself.

But done. Four wrappers seemed like too many, so I overdid it a template
instead.

   // First translate all path variables we recognize.
   for (size_t i = 0; i < arraysize(win_folder_mapping); ++i) {
     size_t position = result.find(win_folder_mapping[i].name);
     if (position != std::wstring::npos) {
       WCHAR path[MAX_PATH];
-      ::SHGetSpecialFolderPath(0, path, win_folder_mapping[i].id, false);
+      sh_get_special_folder_path(0, path, win_folder_mapping[i].id, false);
       std::wstring path_string(path);
       result.replace(position, wcslen(win_folder_mapping[i].name), path_string);
     }
   }
   // Next translate other windows specific variables.
+  static auto get_user_name = reinterpret_cast<decltype(::GetUserName)*>(
+      GetProcAddress(LoadLibrary(L"advapi32.dll"), "GetUserNameW"));
   size_t position = result.find(kUserNamePolicyVarName);
   if (position != std::wstring::npos) {
     DWORD return_length = 0;
-    ::GetUserName(NULL, &return_length);
+    get_user_name(NULL, &return_length);
     if (return_length != 0) {
       std::unique_ptr<WCHAR[]> username(new WCHAR[return_length]);
-      ::GetUserName(username.get(), &return_length);
+      get_user_name(username.get(), &return_length);
       std::wstring username_string(username.get());
       result.replace(position, wcslen(kUserNamePolicyVarName), username_string);
     }
   }
   position = result.find(kMachineNamePolicyVarName);
   if (position != std::wstring::npos) {
     DWORD return_length = 0;
     ::GetComputerNameEx(ComputerNamePhysicalDnsHostname, NULL, &return_length);
     if (return_length != 0) {
       std::unique_ptr<WCHAR[]> machinename(new WCHAR[return_length]);
       ::GetComputerNameEx(ComputerNamePhysicalDnsHostname,
                           machinename.get(), &return_length);
       std::wstring machinename_string(machinename.get());
       result.replace(
           position, wcslen(kMachineNamePolicyVarName), machinename_string);
     }
   }
+  static auto wts_query_session_information =
+      reinterpret_cast<decltype(::WTSQuerySessionInformation)*>(GetProcAddress(
+          LoadLibrary(L"wtsapi32.dll"), "WTSQuerySessionInformationW"));
+  static auto wts_free_memory = reinterpret_cast<decltype(::WTSFreeMemory)*>(
+      GetProcAddress(LoadLibrary(L"wtsapi32.dll"), "WTSFreeMemory"));
   position = result.find(kWinClientName);
   if (position != std::wstring::npos) {
     LPWSTR buffer = NULL;
     DWORD buffer_length = 0;
-    if (::WTSQuerySessionInformation(WTS_CURRENT_SERVER, WTS_CURRENT_SESSION,
-                                     WTSClientName,
-                                     &buffer, &buffer_length)) {
+    if (wts_query_session_information(WTS_CURRENT_SERVER, WTS_CURRENT_SESSION,
+                                      WTSClientName, &buffer, &buffer_length)) {
       std::wstring clientname_string(buffer);
       result.replace(position, wcslen(kWinClientName), clientname_string);
-      ::WTSFreeMemory(buffer);
+      wts_free_memory(buffer);
     }
   }
   position = result.find(kWinSessionName);
   if (position != std::wstring::npos) {
     LPWSTR buffer = NULL;
     DWORD buffer_length = 0;
-    if (::WTSQuerySessionInformation(WTS_CURRENT_SERVER, WTS_CURRENT_SESSION,
-                                     WTSWinStationName,
-                                     &buffer, &buffer_length)) {
+    if (wts_query_session_information(WTS_CURRENT_SERVER, WTS_CURRENT_SESSION,
+                                      WTSWinStationName, &buffer,
+                                      &buffer_length)) {
       std::wstring sessionname_string(buffer);
       result.replace(position, wcslen(kWinSessionName), sessionname_string);
-      ::WTSFreeMemory(buffer);
+      wts_free_memory(buffer);
     }
   }
   // TODO(pastarmovj): Consider reorganizing this code once there are even more
   // variables to be supported. The search for the var and its replacement can
   // be extracted as common functionality.
 
   return result;
 }
 
-void CheckUserDataDirPolicy(base::FilePath* user_data_dir) {
-  DCHECK(user_data_dir);
-  // Policy from the HKLM hive has precedence over HKCU.
-  if (!LoadUserDataDirPolicyFromRegistry(HKEY_LOCAL_MACHINE, key::kUserDataDir,
-                                         user_data_dir)) {
-    LoadUserDataDirPolicyFromRegistry(HKEY_CURRENT_USER, key::kUserDataDir,
-                                      user_data_dir);
-  }
-}
-
-void CheckDiskCacheDirPolicy(base::FilePath* disk_cache_dir) {
-  DCHECK(disk_cache_dir);
-  if (!LoadUserDataDirPolicyFromRegistry(HKEY_LOCAL_MACHINE, key::kDiskCacheDir,
-                                         disk_cache_dir)) {
-    LoadUserDataDirPolicyFromRegistry(HKEY_CURRENT_USER, key::kDiskCacheDir,
-                                      disk_cache_dir);
-  }
-}
-
-}  // namespace path_parser
-
-}  // namespace policy
+}  // namespace install_static