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

chrome/browser/process_singleton_posix.cc

Index: chrome/browser/process_singleton_posix.cc
diff --git a/chrome/browser/process_singleton_posix.cc b/chrome/browser/process_singleton_posix.cc
index f8786c67e6404c2678b65f8c0b16da815ce02d74..cf234d0a71e0aeb79d1f8dec98195eb2e65baf98 100644
--- a/chrome/browser/process_singleton_posix.cc
+++ b/chrome/browser/process_singleton_posix.cc
@@ -464,6 +464,20 @@ bool ReplaceOldSingletonLock(const base::FilePath& symlink_content,
 }
 #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
 
 ///////////////////////////////////////////////////////////////////////////////
@@ -776,6 +790,7 @@ ProcessSingleton::NotifyResult ProcessSingleton::NotifyOtherProcessWithTimeout(
     if (hostname.empty()) {
       // Invalid lockfile.
       UnlinkPath(lock_path_);
+      SendRemoteProcessInteractionResultHistogram(INVALID_LOCK_FILE);
       return PROCESS_NONE;
     }
 
@@ -784,6 +799,7 @@ ProcessSingleton::NotifyResult ProcessSingleton::NotifyOtherProcessWithTimeout(
       // 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;
@@ -792,6 +808,7 @@ ProcessSingleton::NotifyResult ProcessSingleton::NotifyOtherProcessWithTimeout(
     if (!IsChromeProcess(pid)) {
       // Orphaned lockfile (no process with pid, or non-chrome process.)
       UnlinkPath(lock_path_);
+      SendRemoteProcessInteractionResultHistogram(ORPHANED_LOCK_FILE);
       return PROCESS_NONE;
     }
 
@@ -799,6 +816,7 @@ ProcessSingleton::NotifyResult ProcessSingleton::NotifyOtherProcessWithTimeout(
       // 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;
     }
 
@@ -806,6 +824,7 @@ ProcessSingleton::NotifyResult ProcessSingleton::NotifyOtherProcessWithTimeout(
       // Retries failed.  Kill the unresponsive chrome process and continue.
       if (!kill_unresponsive || !KillProcessByLockPath())
         return PROFILE_IN_USE;
+      SendRemoteHungProcessTerminateReasonHistogram(NOTIFY_ATTEMPTS_EXCEEDED);
       return PROCESS_NONE;
     }
 
@@ -841,6 +860,7 @@ ProcessSingleton::NotifyResult ProcessSingleton::NotifyOtherProcessWithTimeout(
     // 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;
   }
 
@@ -856,12 +876,14 @@ ProcessSingleton::NotifyResult ProcessSingleton::NotifyOtherProcessWithTimeout(
   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)
@@ -1057,18 +1079,25 @@ bool ProcessSingleton::KillProcessByLockPath() {
   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);

[gab, 2017/05/12 18:40:59]

Feels wrong to share histogram for two different code paths (here and above)?

[Alexey Seren, 2017/05/15 08:40:48]

Acknowledged.

+    return res;
   }
   UnlinkPath(lock_path_);
 
-  if (IsSameChromeInstance(pid))
+  if (IsSameChromeInstance(pid)) {
+    SendRemoteProcessInteractionResultHistogram(SAME_BROWSER_INSTANCE);

[gab, 2017/05/12 18:40:59]

ditto

[Alexey Seren, 2017/05/15 08:40:48]

Acknowledged.

     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;
 }
@@ -1080,4 +1109,24 @@ void ProcessSingleton::KillProcess(int pid) {
   // 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);
 }