Added histograms on process singleton create when remote process exists and we cannot notify it

chrome/browser/process_singleton_posix.cc

 // Copyright 2014 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.
 
 // On Linux, when the user tries to launch a second copy of chrome, we check
 // for a socket in the user's profile directory.  If the socket file is open we
 // send a message to the first chrome browser process with the current
 // directory and second process command line flags.  The second process then
 // exits.
 //
@@ skipping 93 matching lines @@
 using content::BrowserThread;
 
 namespace {
 
 // Timeout for the current browser process to respond. 20 seconds should be
 // enough.
 const int kTimeoutInSeconds = 20;
 // Number of retries to notify the browser. 20 retries over 20 seconds = 1 try
 // per second.
 const int kRetryAttempts = 20;
-static bool g_disable_prompt;
 const char kStartToken[] = "START";
 const char kACKToken[] = "ACK";
 const char kShutdownToken[] = "SHUTDOWN";
 const char kTokenDelimiter = '\0';
 const int kMaxMessageLength = 32 * 1024;
 const int kMaxACKMessageLength = arraysize(kShutdownToken) - 1;
 
 const char kLockDelimiter = '-';
 
+bool g_disable_prompt = false;
+bool g_skip_is_chrome_process_check = false;
+
 // Set the close-on-exec bit on a file descriptor.
 // Returns 0 on success, -1 on failure.
 int SetCloseOnExec(int fd) {
   int flags = fcntl(fd, F_GETFD, 0);
   if (-1 == flags)
     return flags;
   if (flags & FD_CLOEXEC)
     return 0;
   return fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
 }
@@ skipping 197 matching lines @@
   return true;
 #endif
 
   NOTREACHED();
   return false;
 }
 
 bool IsChromeProcess(pid_t pid) {
   base::FilePath other_chrome_path(base::GetProcessExecutablePath(pid));
   return (!other_chrome_path.empty() &&
-          other_chrome_path.BaseName() ==
-          base::FilePath(chrome::kBrowserProcessExecutableName));
+          (g_skip_is_chrome_process_check ||
+           other_chrome_path.BaseName() ==
+               base::FilePath(chrome::kBrowserProcessExecutableName)));
 }
 
 // A helper class to hold onto a socket.
 class ScopedSocket {
  public:
   ScopedSocket() : fd_(-1) { Reset(); }
   ~ScopedSocket() { Close(); }
   int fd() { return fd_; }
   void Reset() {
     Close();
@@ skipping 104 matching lines @@
   // version has run.
   if (!base::DeleteFile(lock_path, false)) {
     PLOG(ERROR) << "Could not delete old singleton lock.";
     return false;
   }
 
   return SymlinkPath(symlink_content, lock_path);
 }
 #endif  // defined(OS_MACOSX)
 
+void SendRemoteProcessInteractionResultHistogram(
+    ProcessSingleton::RemoteProcessInteractionResult result) {
+  UMA_HISTOGRAM_ENUMERATION(
+      "Chrome.ProcessSingleton.RemoteProcessInteractionResult", result,
+      ProcessSingleton::REMOTE_PROCESS_INTERACTION_RESULT_COUNT);
+}
+
+void SendRemoteHungProcessTerminateReasonHistogram(
+    ProcessSingleton::RemoteHungProcessTerminateReason reason) {
+  UMA_HISTOGRAM_ENUMERATION(
+      "Chrome.ProcessSingleton.RemoteHungProcessTerminateReason", reason,
+      ProcessSingleton::REMOTE_HUNG_PROCESS_TERMINATE_REASON_COUNT);
+}
+
 }  // namespace
 
 ///////////////////////////////////////////////////////////////////////////////
 // ProcessSingleton::LinuxWatcher
 // A helper class for a Linux specific implementation of the process singleton.
 // This class sets up a listener on the singleton socket and handles parsing
 // messages that come in on the singleton socket.
 class ProcessSingleton::LinuxWatcher
     : public base::RefCountedThreadSafe<ProcessSingleton::LinuxWatcher,
                                         BrowserThread::DeleteOnIOThread> {
@@ skipping 292 matching lines @@
     std::string hostname;
     int pid;
     if (!ParseLockPath(lock_path_, &hostname, &pid)) {
       // No lockfile exists.
       return PROCESS_NONE;
     }
 
     if (hostname.empty()) {
       // Invalid lockfile.
       UnlinkPath(lock_path_);
+      SendRemoteProcessInteractionResultHistogram(INVALID_LOCK_FILE);
       return PROCESS_NONE;
     }
 
     if (hostname != net::GetHostName() && !IsChromeProcess(pid)) {
       // Locked by process on another host. If the user selected to unlock
       // the profile, try to continue; otherwise quit.
       if (DisplayProfileInUseError(lock_path_, hostname, pid)) {
         UnlinkPath(lock_path_);
+        SendRemoteProcessInteractionResultHistogram(PROFILE_UNLOCKED);
         return PROCESS_NONE;
       }
       return PROFILE_IN_USE;
     }
 
     if (!IsChromeProcess(pid)) {
       // Orphaned lockfile (no process with pid, or non-chrome process.)
       UnlinkPath(lock_path_);
+      SendRemoteProcessInteractionResultHistogram(ORPHANED_LOCK_FILE);
       return PROCESS_NONE;
     }
 
     if (IsSameChromeInstance(pid)) {
       // Orphaned lockfile (pid is part of same chrome instance we are, even
       // though we haven't tried to create a lockfile yet).
       UnlinkPath(lock_path_);
+      SendRemoteProcessInteractionResultHistogram(SAME_BROWSER_INSTANCE);
       return PROCESS_NONE;
     }
 
     if (retries == retry_attempts) {
       // Retries failed.  Kill the unresponsive chrome process and continue.
       if (!kill_unresponsive || !KillProcessByLockPath())
         return PROFILE_IN_USE;
+      SendRemoteHungProcessTerminateReasonHistogram(NOTIFY_ATTEMPTS_EXCEEDED);
       return PROCESS_NONE;
     }
 
     base::PlatformThread::Sleep(sleep_interval);
   }
 
   timeval socket_timeout = TimeDeltaToTimeVal(timeout);
   setsockopt(socket.fd(),
              SOL_SOCKET,
              SO_SNDTIMEO,
@@ skipping 15 matching lines @@
       it != argv.end(); ++it) {
     to_send.push_back(kTokenDelimiter);
     to_send.append(*it);
   }
 
   // Send the message
   if (!WriteToSocket(socket.fd(), to_send.data(), to_send.length())) {
     // Try to kill the other process, because it might have been dead.
     if (!kill_unresponsive || !KillProcessByLockPath())
       return PROFILE_IN_USE;
+    SendRemoteHungProcessTerminateReasonHistogram(SOCKET_WRITE_FAILED);
     return PROCESS_NONE;
   }
 
   if (shutdown(socket.fd(), SHUT_WR) < 0)
     PLOG(ERROR) << "shutdown() failed";
 
   // Read ACK message from the other process. It might be blocked for a certain
   // timeout, to make sure the other process has enough time to return ACK.
   char buf[kMaxACKMessageLength + 1];
   ssize_t len = ReadFromSocket(socket.fd(), buf, kMaxACKMessageLength, timeout);
 
   // Failed to read ACK, the other process might have been frozen.
   if (len <= 0) {
     if (!kill_unresponsive || !KillProcessByLockPath())
       return PROFILE_IN_USE;
+    SendRemoteHungProcessTerminateReasonHistogram(SOCKET_READ_FAILED);
     return PROCESS_NONE;
   }
 
   buf[len] = '\0';
   if (strncmp(buf, kShutdownToken, arraysize(kShutdownToken) - 1) == 0) {
     // The other process is shutting down, it's safe to start a new process.
+    SendRemoteProcessInteractionResultHistogram(REMOTE_PROCESS_SHUTTING_DOWN);
     return PROCESS_NONE;
   } else if (strncmp(buf, kACKToken, arraysize(kACKToken) - 1) == 0) {
 #if defined(TOOLKIT_VIEWS) && defined(OS_LINUX) && !defined(OS_CHROMEOS)
     // Likely NULL in unit tests.
     views::LinuxUI* linux_ui = views::LinuxUI::instance();
     if (linux_ui)
       linux_ui->NotifyWindowManagerStartupComplete();
 #endif
 
     // Assume the other process is handling the request.
@@ skipping 63 matching lines @@
 
 void ProcessSingleton::OverrideKillCallbackForTesting(
     const base::Callback<void(int)>& callback) {
   kill_callback_ = callback;
 }
 
 void ProcessSingleton::DisablePromptForTesting() {
   g_disable_prompt = true;
 }
 
+void ProcessSingleton::SkipIsChromeProcessCheckForTesting(bool skip) {
+  g_skip_is_chrome_process_check = skip;
+}
+
 bool ProcessSingleton::Create() {
   int sock;
   sockaddr_un addr;
 
   // The symlink lock is pointed to the hostname and process id, so other
   // processes can find it out.
   base::FilePath symlink_content(base::StringPrintf(
       "%s%c%u",
       net::GetHostName().c_str(),
       kLockDelimiter,
@@ skipping 92 matching lines @@
   }
   return true;
 }
 
 bool ProcessSingleton::KillProcessByLockPath() {
   std::string hostname;
   int pid;
   ParseLockPath(lock_path_, &hostname, &pid);
 
   if (!hostname.empty() && hostname != net::GetHostName()) {
-    return DisplayProfileInUseError(lock_path_, hostname, pid);
+    bool res = DisplayProfileInUseError(lock_path_, hostname, pid);
+    if (res)
+      SendRemoteProcessInteractionResultHistogram(PROFILE_UNLOCKED_BEFORE_KILL);
+    return res;
   }
   UnlinkPath(lock_path_);
 
-  if (IsSameChromeInstance(pid))
+  if (IsSameChromeInstance(pid)) {
+    SendRemoteProcessInteractionResultHistogram(
+        SAME_BROWSER_INSTANCE_BEFORE_KILL);
     return true;
+  }
 
   if (pid > 0) {
     kill_callback_.Run(pid);
     return true;
   }
 
+  SendRemoteProcessInteractionResultHistogram(FAILED_TO_EXTRACT_PID);
+
   LOG(ERROR) << "Failed to extract pid from path: " << lock_path_.value();
   return true;
 }
 
 void ProcessSingleton::KillProcess(int pid) {
   // TODO(james.su@gmail.com): Is SIGKILL ok?
   int rv = kill(static_cast<base::ProcessHandle>(pid), SIGKILL);
   // ESRCH = No Such Process (can happen if the other process is already in
   // progress of shutting down and finishes before we try to kill it).
   DCHECK(rv == 0 || errno == ESRCH) << "Error killing process: "
                                     << base::safe_strerror(errno);
+
+  int error_code = (rv == 0) ? 0 : errno;
+  UMA_HISTOGRAM_SPARSE_SLOWLY(
+      "Chrome.ProcessSingleton.TerminateProcessErrorCode.Posix", error_code);
+
+  RemoteProcessInteractionResult action = TERMINATE_SUCCEEDED;
+  if (rv != 0) {
+    switch (error_code) {
+      case ESRCH:
+        action = REMOTE_PROCESS_NOT_FOUND;
+        break;
+      case EPERM:
+        action = TERMINATE_NOT_ENOUGH_PERMISSIONS;
+        break;
+      default:
+        action = TERMINATE_FAILED;
+        break;
+    }
+  }
+  SendRemoteProcessInteractionResultHistogram(action);
 }