commit 690810b2a0c45b6e4c0c2257c6e7c189cf3bba25
author Alex Deymo <deymo@google.com> Tue Jan 19 16:11:40 2016 -0800
committer Alex Deymo <deymo@google.com> Tue Jan 19 16:16:50 2016 -0800
tree a3e3a1fa840a930cf82b9a7b7cac754e7efbd460
parent e78e3fb71d9b1586482aa43514c0d6625c0ae197

update_engine_client: Prevent hanging the client.

We can't call QuitWithExitCode() from the OnInit() method. This CL
delays the flag processing until the initialization of the daemon is
done.

Other minor linter changes included in this CL.

Bug: None
TEST=`update_engine_client --status` works.

Change-Id: I495397015b5d31dcd2cc9e8de52b8e607c5bd7c7

update_engine_client.cc

diff --git a/update_engine_client.cc b/update_engine_client.cc
index f062813..b94ee61 100644
--- a/update_engine_client.cc
+++ b/update_engine_client.cc
@@ -34,11 +34,11 @@
 #include "update_engine/update_status.h"
 #include "update_status_utils.h"
 
+using chromeos_update_engine::UpdateStatusToString;
 using std::string;
 using std::unique_ptr;
 using std::vector;
 using update_engine::UpdateStatus;
-using chromeos_update_engine::UpdateStatusToString;
 
 namespace {
 
@@ -65,14 +65,16 @@
       return 1;
     }
 
-    ret = ProcessFlags();
-    if (ret != kContinueRunning) QuitWithExitCode(ret);
-
+    // We can't call QuitWithExitCode from OnInit(), so we delay the execution
+    // of the ProcessFlags method after the Daemon initialization is done.
+    base::MessageLoop::current()->PostTask(
+        FROM_HERE,
+        base::Bind(&UpdateEngineClient::ProcessFlagsAndExit,
+                   base::Unretained(this)));
     return EX_OK;
   }
 
  private:
-
   // Show the status of the update engine in stdout.
   bool ShowStatus();
 
@@ -81,9 +83,13 @@
   int GetNeedReboot();
 
   // Main method that parses and triggers all the actions based on the passed
-  // flags.
+  // flags. Returns the exit code of the program of kContinueRunning if it
+  // should not exit.
   int ProcessFlags();
 
+  // Processes the flags and exits the program accordingly.
+  void ProcessFlagsAndExit();
+
   // Copy of argc and argv passed to main().
   int argc_;
   char** argv_;
@@ -116,9 +122,10 @@
  public:
   ~WatchingStatusUpdateHandler() override = default;
 
-  void HandleStatusUpdate(int64_t last_checked_time, double progress,
+  void HandleStatusUpdate(int64_t last_checked_time,
+                          double progress,
                           UpdateStatus current_operation,
-                          const std::string& new_version,
+                          const string& new_version,
                           int64_t new_size) override;
 };
 
@@ -176,13 +183,15 @@
 
 class UpdateWaitHandler : public ExitingStatusUpdateHandler {
  public:
-  UpdateWaitHandler(bool exit_on_error) : exit_on_error_(exit_on_error) {}
+  explicit UpdateWaitHandler(bool exit_on_error)
+      : exit_on_error_(exit_on_error) {}
 
   ~UpdateWaitHandler() override = default;
 
-  void HandleStatusUpdate(int64_t last_checked_time, double progress,
+  void HandleStatusUpdate(int64_t last_checked_time,
+                          double progress,
                           UpdateStatus current_operation,
-                          const std::string& new_version,
+                          const string& new_version,
                           int64_t new_size) override;
 
  private:
@@ -259,7 +268,7 @@
   brillo::FlagHelper::Init(argc_, argv_, "Chromium OS Update Engine Client");
 
   // Ensure there are no positional arguments.
-  const std::vector<string> positional_args =
+  const vector<string> positional_args =
       base::CommandLine::ForCurrentProcess()->GetArgs();
   if (!positional_args.empty()) {
     LOG(ERROR) << "Found a positional argument '" << positional_args.front()
@@ -503,6 +512,12 @@
   return 0;
 }
 
+void UpdateEngineClient::ProcessFlagsAndExit() {
+  int ret = ProcessFlags();
+  if (ret != kContinueRunning)
+    QuitWithExitCode(ret);
+}
+
 }  // namespace
 
 int main(int argc, char** argv) {