safer calls to IsProcessRunning (#131)

* safer calls to IsProcessRunning to handle cases where we can't check status of processes

2 files changed, 63 insertions, 16 deletions

diff --git a/src/zenserver/main.cpp b/src/zenserver/main.cpp
index 93516f5fd..25a5d5cf5 100644
--- a/src/zenserver/main.cpp
+++ b/src/zenserver/main.cpp
@@ -109,12 +109,27 @@ ZenEntryPoint::Run()
 		{
 			if (m_ServerOptions.OwnerPid)
 			{
-				if (!IsProcessRunning(m_ServerOptions.OwnerPid))
+				std::error_code Ec;
+				if (!IsProcessRunning(m_ServerOptions.OwnerPid, Ec))
 				{
-					ZEN_WARN("Sponsor owner pid {} is no longer running, will not add sponsor to process listening to port {} (pid: {})",
-							 m_ServerOptions.OwnerPid,
-							 m_ServerOptions.BasePort,
-							 Entry->Pid.load());
+					if (Ec)
+					{
+						ZEN_WARN(
+							"Sponsor owner pid {} can not be checked for running state, reason: '{}'. Will not add sponsor to process "
+							"listening to port {} (pid: {})",
+							m_ServerOptions.OwnerPid,
+							Ec.message(),
+							m_ServerOptions.BasePort,
+							Entry->Pid.load());
+					}
+					else
+					{
+						ZEN_WARN(
+							"Sponsor owner pid {} is no longer running, will not add sponsor to process listening to port {} (pid: {})",
+							m_ServerOptions.OwnerPid,
+							m_ServerOptions.BasePort,
+							Entry->Pid.load());
+					}
 					std::exit(1);
 				}
 				ZEN_INFO(
diff --git a/src/zenutil/zenserverprocess.cpp b/src/zenutil/zenserverprocess.cpp
index 84544bac8..29d590d00 100644
--- a/src/zenutil/zenserverprocess.cpp
+++ b/src/zenutil/zenserverprocess.cpp
@@ -249,7 +249,8 @@ ZenServerState::Lookup(int DesiredListenPort) const
 		{
 			if (DesiredListenPort == 0 || (EntryPort == DesiredListenPort))
 			{
-				if (IsProcessRunning(m_Data[i].Pid))
+				std::error_code _;
+				if (IsProcessRunning(m_Data[i].Pid, _))
 				{
 					return &m_Data[i];
 				}
@@ -270,7 +271,8 @@ ZenServerState::LookupByEffectivePort(int Port) const
 		{
 			if (EntryPort == Port)
 			{
-				if (IsProcessRunning(m_Data[i].Pid))
+				std::error_code _;
+				if (IsProcessRunning(m_Data[i].Pid, _))
 				{
 					return &m_Data[i];
 				}
@@ -337,11 +339,21 @@ ZenServerState::Sweep()
 
 		if (Entry.DesiredListenPort)
 		{
-			if (Entry.Pid != 0 && IsProcessRunning(Entry.Pid) == false)
+			std::error_code ErrorCode;
+			if (Entry.Pid != 0 && IsProcessRunning(Entry.Pid, ErrorCode) == false)
 			{
-				ZEN_DEBUG("Sweep - pid {} not running, reclaiming entry (port {})", Entry.Pid.load(), Entry.DesiredListenPort.load());
-
-				Entry.Reset();
+				if (ErrorCode)
+				{
+					ZEN_WARN("Sweep - can not determine running state for pid {}, skipping entry (port {}). Reason: '{}'",
+							 Entry.Pid.load(),
+							 Entry.DesiredListenPort.load(),
+							 ErrorCode.message());
+				}
+				else
+				{
+					ZEN_DEBUG("Sweep - pid {} not running, reclaiming entry (port {})", Entry.Pid.load(), Entry.DesiredListenPort.load());
+					Entry.Reset();
+				}
 			}
 		}
 	}
@@ -361,9 +373,20 @@ ZenServerState::Snapshot(std::function<void(const ZenServerEntry&)>&& Callback)
 
 		if (Entry.Pid != 0 && Entry.DesiredListenPort)
 		{
-			if (IsProcessRunning(Entry.Pid.load()))
+			std::error_code ErrorCode;
+			if (IsProcessRunning(Entry.Pid.load(), ErrorCode))
 			{
-				Callback(Entry);
+				if (ErrorCode)
+				{
+					ZEN_WARN("Snapshot - can not determine running state for pid {}, skipping entry (port {}). Reason: '{}'",
+							 Entry.Pid.load(),
+							 Entry.DesiredListenPort.load(),
+							 ErrorCode.message());
+				}
+				else
+				{
+					Callback(Entry);
+				}
 			}
 		}
 	}
@@ -415,7 +438,8 @@ ZenServerState::ZenServerEntry::AddSponsorProcess(uint32_t PidToAdd, uint64_t Ti
 			{
 				return false;
 			}
-			if (!IsProcessRunning(ServerPid))
+			std::error_code _;
+			if (!IsProcessRunning(ServerPid, _))
 			{
 				return false;
 			}
@@ -995,9 +1019,17 @@ ValidateLockFileInfo(const LockFileInfo& Info, std::string& OutReason)
 		OutReason = fmt::format("process ({}) is invalid", Info.Pid);
 		return false;
 	}
-	if (!IsProcessRunning(Info.Pid))
+	std::error_code ErrorCode;
+	if (!IsProcessRunning(Info.Pid, ErrorCode))
 	{
-		OutReason = fmt::format("process ({}) is not running", Info.Pid);
+		if (ErrorCode)
+		{
+			OutReason = fmt::format("process ({}) can not be checked. Reason: '{}'", Info.Pid, ErrorCode.message());
+		}
+		else
+		{
+			OutReason = fmt::format("process ({}) is not running", Info.Pid);
+		}
 		return false;
 	}
 	if (Info.SessionId == Oid::Zero)