Allow ZenMap to fallback to local shared memory when running non elevated.

1 files changed, 22 insertions, 0 deletions

diff --git a/zenutil/zenserverprocess.cpp b/zenutil/zenserverprocess.cpp
index 4098954a8..b43e86f00 100644
--- a/zenutil/zenserverprocess.cpp
+++ b/zenutil/zenserverprocess.cpp
@@ -89,11 +89,19 @@ ZenServerState::Initialize()
 {
 	// TODO: there's a small chance of a race here, this logic could be tightened up with a mutex to
 	//		 ensure only a single process at a time creates the mapping
+	// TODO: the fallback to Local instead of Global has a flaw where if you start a non-elevated instance
+	//		 first then start an elevated instance second you'll have the first instance with a local
+	//		 mapping and the second instance with a global mapping.  This kind of elevated/non-elevated
+	//		 shouldn't be common, but handling for it should be improved in the future.
 
 	if (HANDLE hMap = OpenFileMapping(FILE_MAP_ALL_ACCESS, FALSE, L"Global\\ZenMap"))
 	{
 		m_hMapFile = hMap;
 	}
+	else if (HANDLE hMap = OpenFileMapping(FILE_MAP_ALL_ACCESS, FALSE, L"Local\\ZenMap"))
+	{
+		m_hMapFile = hMap;
+	}
 	else
 	{
 		// Security attributes to enable any user to access state
@@ -108,6 +116,16 @@ ZenServerState::Initialize()
 
 		if (hMap == NULL)
 		{
+			hMap = CreateFileMapping(INVALID_HANDLE_VALUE,						// use paging file
+									 Attrs.Attributes(),						// allow anyone to access
+									 PAGE_READWRITE,							// read/write access
+									 0,											// maximum object size (high-order DWORD)
+									 m_MaxEntryCount * sizeof(ZenServerEntry),	// maximum object size (low-order DWORD)
+									 L"Local\\ZenMap");						// name of mapping object
+		}
+
+		if (hMap == NULL)
+		{
 			ThrowLastError("Could not open or create file mapping object for Zen server state");
 		}
 
@@ -136,6 +154,10 @@ ZenServerState::InitializeReadOnly()
 	{
 		m_hMapFile = hMap;
 	}
+	else if (HANDLE hMap = OpenFileMapping(FILE_MAP_ALL_ACCESS, FALSE, L"Local\\ZenMap"))
+	{
+		m_hMapFile = hMap;
+	}
 	else
 	{
 		return false;