Add support for Flash Player Component updates on Linux

chrome/browser/component_updater/pepper_flash_component_installer.cc

Index: chrome/browser/component_updater/pepper_flash_component_installer.cc
diff --git a/chrome/browser/component_updater/pepper_flash_component_installer.cc b/chrome/browser/component_updater/pepper_flash_component_installer.cc
index 2ebbb31854080d51bc574bc9aebdb89ad23aa79e..c9dc6ca04f61a7d59a374975dc8aae04bf69ab62 100644
--- a/chrome/browser/component_updater/pepper_flash_component_installer.cc
+++ b/chrome/browser/component_updater/pepper_flash_component_installer.cc
@@ -13,8 +13,11 @@
 #include "base/files/file_enumerator.h"
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
+#include "base/files/important_file_writer.h"

[rickyz (no longer on Chrome), 2015/07/31 00:13:56]

Are these still used in this file?

[Greg K, 2015/08/04 00:21:16]

Done.

+#include "base/files/memory_mapped_file.h"
 #include "base/logging.h"
 #include "base/path_service.h"
+#include "base/stl_util.h"
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
@@ -25,6 +28,7 @@
 #include "chrome/common/chrome_constants.h"
 #include "chrome/common/chrome_paths.h"
 #include "chrome/common/chrome_switches.h"
+#include "chrome/common/component_flash_hint_file.h"
 #include "chrome/common/pepper_flash.h"
 #include "chrome/common/ppapi_utils.h"
 #include "components/component_updater/component_updater_service.h"
@@ -33,6 +37,7 @@
 #include "content/public/browser/plugin_service.h"
 #include "content/public/common/content_constants.h"
 #include "content/public/common/pepper_plugin_info.h"
+#include "crypto/sha2.h"
 #include "flapper_version.h"  // In SHARED_INTERMEDIATE_DIR.  NOLINT
 #include "ppapi/shared_impl/ppapi_permissions.h"
 
@@ -43,7 +48,7 @@ namespace component_updater {
 
 namespace {
 
-#if defined(GOOGLE_CHROME_BUILD) && !defined(OS_LINUX)
+#if defined(GOOGLE_CHROME_BUILD)
 // CRX hash. The extension id is: mimojjlkmoijpicakmndhoigimigcmbb.
 const uint8_t kSha2Hash[] = {0xc8, 0xce, 0x99, 0xba, 0xce, 0x89, 0xf8, 0x20,
                              0xac, 0xd3, 0x7e, 0x86, 0x8c, 0x86, 0x2c, 0x11,
@@ -53,7 +58,7 @@ const uint8_t kSha2Hash[] = {0xc8, 0xce, 0x99, 0xba, 0xce, 0x89, 0xf8, 0x20,
 // If we don't have a Pepper Flash component, this is the version we claim.
 const char kNullVersion[] = "0.0.0.0";
 
-#endif  // defined(GOOGLE_CHROME_BUILD) && !defined(OS_LINUX)
+#endif  // defined(GOOGLE_CHROME_BUILD)
 
 // The base directory on Windows looks like:
 // <profile>\AppData\Local\Google\Chrome\User Data\PepperFlash\.
@@ -63,7 +68,7 @@ base::FilePath GetPepperFlashBaseDirectory() {
   return result;
 }
 
-#if defined(GOOGLE_CHROME_BUILD) && !defined(OS_LINUX)
+#if defined(GOOGLE_CHROME_BUILD)
 // Pepper Flash plugins have the version encoded in the path itself
 // so we need to enumerate the directories to find the full path.
 // On success, |latest_dir| returns something like:
@@ -99,8 +104,9 @@ bool GetPepperFlashDirectory(base::FilePath* latest_dir,
   }
   return found;
 }
-#endif  // defined(GOOGLE_CHROME_BUILD) && !defined(OS_LINUX)
+#endif  // defined(GOOGLE_CHROME_BUILD)
 
+#if !defined(OS_LINUX) || defined(GOOGLE_CHROME_BUILD)
 bool MakePepperFlashPluginInfo(const base::FilePath& flash_path,
                                const Version& flash_version,
                                bool out_of_process,
@@ -177,6 +183,7 @@ void RegisterPepperFlashWithChrome(const base::FilePath& path,
       plugin_info.ToWebPluginInfo(), true);
   PluginService::GetInstance()->RefreshPlugins();
 }
+#endif  // !defined(OS_LINUX) || defined(GOOGLE_CHROME_BUILD)
 
 }  // namespace
 
@@ -219,24 +226,47 @@ bool PepperFlashComponentInstaller::Install(
     return false;
   if (current_version_.CompareTo(version) > 0)
     return false;
-  if (!base::PathExists(unpack_path.Append(chrome::kPepperFlashPluginFilename)))
+  base::FilePath unpacked_plugin =
+      unpack_path.Append(chrome::kPepperFlashPluginFilename);
+  if (!base::PathExists(unpacked_plugin))
     return false;
   // Passed the basic tests. Time to install it.
   base::FilePath path =
       GetPepperFlashBaseDirectory().AppendASCII(version.GetString());
   if (base::PathExists(path))
     return false;
+  current_version_ = version;
+
+#if defined(OS_LINUX)
+  // Populate the component updated flash hint file so that the zygote can
+  // locate and preload the latest version of flash.
+  base::FilePath flash_path = path.Append(chrome::kPepperFlashPluginFilename);
+  chrome::ComponentFlashHintFile hint_file;
+  if (!hint_file.RecordFlashUpdate(unpacked_plugin, flash_path,

[rickyz (no longer on Chrome), 2015/07/31 00:13:56]

I'd probably prefer to write the new flash library first, then record the
update, the rationale being that the way it currently is, if the process dies
between the move and the revert, the next chrome launch will fall back to the
bundled version (as opposed to the previously component update version).

If the write/record were switched, then the only negative consequence would be
an unused copy of flash sitting in the directory, which seems slightly less bad
to me (though you'd probably also have to handle the target existing in the
move).

[Greg K, 2015/08/04 00:21:17]

It's a valid point. As you say, I will need to make sure the installer can deal
with the pre-existing directory the next time around if it attempts to retry the
installation. Otherwise, if the hint file cannot be written out, the install
will permanently fail.

+                                   version.GetString()))
+    return false;
+
+  if (!base::Move(unpack_path, path)) {
+    // If the install failed, try to put the previous hint file back.
+    if (!hint_file.Revert())
+      LOG(WARNING) << "Could not move updated component flash into place, and "
+                      "failed to revert the component flash hint file.";
+    return false;
+  }
+#else
   if (!base::Move(unpack_path, path))
     return false;
+  path = path.Append(chrome::kPepperFlashPluginFilename);
   // Installation is done. Now tell the rest of chrome. Both the path service
-  // and to the plugin service.
-  current_version_ = version;
+  // and to the plugin service. On Linux, a restart is required to use the new
+  // Flash version, so we do not do this.
   PathService::Override(chrome::DIR_PEPPER_FLASH_PLUGIN, path);
   path = path.Append(chrome::kPepperFlashPluginFilename);
   BrowserThread::PostTask(
       BrowserThread::UI,
       FROM_HERE,
       base::Bind(&RegisterPepperFlashWithChrome, path, version));
+#endif  // !defined(OS_LINUX)
   return true;
 }
 
@@ -254,7 +284,7 @@ bool PepperFlashComponentInstaller::Uninstall() {
 
 namespace {
 
-#if defined(GOOGLE_CHROME_BUILD) && !defined(OS_LINUX)
+#if defined(GOOGLE_CHROME_BUILD)
 void FinishPepperFlashUpdateRegistration(ComponentUpdateService* cus,
                                          const Version& version) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
@@ -311,12 +341,12 @@ void StartPepperFlashUpdateRegistration(ComponentUpdateService* cus) {
     base::DeleteFile(*iter, true);
   }
 }
-#endif  // defined(GOOGLE_CHROME_BUILD) && !defined(OS_LINUX)
+#endif  // defined(GOOGLE_CHROME_BUILD)
 
 }  // namespace
 
 void RegisterPepperFlashComponent(ComponentUpdateService* cus) {
-#if defined(GOOGLE_CHROME_BUILD) && !defined(OS_LINUX)
+#if defined(GOOGLE_CHROME_BUILD)
   // Component updated flash supersedes bundled flash therefore if that one
   // is disabled then this one should never install.
   base::CommandLine* cmd_line = base::CommandLine::ForCurrentProcess();