Prototype fix for version shear across updates.

chrome/browser/first_run/upgrade_util_win.cc

 // Copyright (c) 2012 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/first_run/upgrade_util.h"
 
 #include <windows.h>
+#include <psapi.h>
 #include <shellapi.h>
 
 #include <algorithm>
 #include <string>
 
 #include "base/base_paths.h"
 #include "base/command_line.h"
 #include "base/environment.h"
 #include "base/file_util.h"
 #include "base/files/file_path.h"
@@ skipping 98 matching lines @@
                           const RelaunchMode& relaunch_mode) {
   scoped_ptr<base::Environment> env(base::Environment::Create());
   std::string version_str;
 
   // Get the version variable and remove it from the environment.
   if (env->GetVar(chrome::kChromeVersionEnvVar, &version_str))
     env->UnSetVar(chrome::kChromeVersionEnvVar);
   else
     version_str.clear();
 
+

[grt (UTC plus 2), 2014/05/09 16:53:08]

nit: remove extra newline

[robertshield, 2014/05/15 16:49:35]

Done.

+  CommandLine chrome_exe_command_line = command_line;
+  base::FilePath current_exe_path(command_line.GetProgram().DirName());

[grt (UTC plus 2), 2014/05/09 16:53:08]

i'm not sure about this. i recently fixed a bugaboo in the installer where the
current command line was being used similarly, and it turned out that due to
ambiguities in the way command lines are generated and parsed at the various
layers (cmd.exe, win32, base::CommandLine), base::CommandLine::GetProgram()
would return only the first "part" of program paths that contained spaces. the
fix was to use base::PathService::Get(base::FILE_EXE, ...) instead.

[robertshield, 2014/05/15 16:49:35]

Done.

+  current_exe_path = current_exe_path.Append(installer::kChromeExe);
+  chrome_exe_command_line.SetProgram(current_exe_path);
+
   if (base::win::GetVersion() < base::win::VERSION_WIN8)
-    return base::LaunchProcess(command_line, base::LaunchOptions(), NULL);
+    return base::LaunchProcess(chrome_exe_command_line,
+                               base::LaunchOptions(), NULL);
 
   // On Windows 8 we always use the delegate_execute for re-launching chrome.
   //
   // Pass this Chrome's Start Menu shortcut path to the relauncher so it can
   // re-activate chrome via ShellExecute.
   base::FilePath chrome_exe;
   if (!PathService::Get(base::FILE_EXE, &chrome_exe)) {
     NOTREACHED();
     return false;
   }
@@ skipping 101 matching lines @@
         if (exit_code == installer::RENAME_SUCCESSFUL)
           return true;
       }
     }
   }
 
   // Rename didn't work so try to rename by calling Google Update
   return InvokeGoogleUpdateForRename();
 }
 
+bool IsRunningOldChrome() {
+  // This figures out the actual file name that the section containing the
+  // mapped exe refers to. This is used instead of GetModuleFileName because the
+  // .exe may have been renamed out from under us while we've been running which
+  // GetModuleFileName won't notice.
+  wchar_t mapped_file_name[MAX_PATH * 2] = {};
+  DWORD returned_chars =

[grt (UTC plus 2), 2014/05/09 16:53:08]

since returned_chars isn't really used, how about:
  if (!::GetMappedFileName(...)) {
    return false;
  }
  base::FilePath file_name(base::FilePath(mapped_file_name).BaseName());
  return base::FilePath::CompareEqualIgnoreCase(file_name.value(),
                                                installer::kChromeOldExe);

[robertshield, 2014/05/15 16:49:35]

Done.

+      ::GetMappedFileName(::GetCurrentProcess(),
+                          reinterpret_cast<void*>(::GetModuleHandle(NULL)),
+                          mapped_file_name,
+                          MAX_PATH * 2);

[grt (UTC plus 2), 2014/05/09 16:53:08]

arraysize(mapped_file_name)

[robertshield, 2014/05/15 16:49:35]

Done.

+  if (returned_chars != 0) {
+    base::FilePath file_name(base::FilePath(mapped_file_name).BaseName());
+    if (base::FilePath::CompareEqualIgnoreCase(file_name.value(),
+                                               installer::kChromeOldExe)) {
+      return true;
+    }
+  }
+  return false;
+}
+
 bool DoUpgradeTasks(const CommandLine& command_line) {
   // The DelegateExecute verb handler finalizes pending in-use updates for
   // metro mode launches, as Chrome cannot be gracefully relaunched when
   // running in this mode.
   if (base::win::IsMetroProcess())
     return false;
-  if (!SwapNewChromeExeIfPresent())
+  if (!SwapNewChromeExeIfPresent() && !IsRunningOldChrome())
     return false;
   // At this point the chrome.exe has been swapped with the new one.
   if (!RelaunchChromeBrowser(command_line)) {
     // The re-launch fails. Feel free to panic now.
     NOTREACHED();
   }
   return true;
 }
 
 }  // namespace upgrade_util