[PATCH 2/4] msi: Protect communication with the custom action server with a critical section.

[Zebediah Figura]

Signed-off-by: Zebediah Figura 
---
Avoids a potential though unlikely race whereby an asynchronous custom action
receives the wrong thread handle.

dlls/msi/custom.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/dlls/msi/custom.c b/dlls/msi/custom.c
index a9bb81f..9418b42 100644
--- a/dlls/msi/custom.c
+++ b/dlls/msi/custom.c
@@ -683,6 +683,8 @@ static DWORD WINAPI custom_client_thread(void *arg)
         pipe = info->package->custom_server_64_pipe;
     }

+    EnterCriticalSection(&msi_custom_action_cs);
+
     if (!WriteFile(pipe, &info->guid, sizeof(info->guid), &size, NULL) ||
         size != sizeof(info->guid))
     {
@@ -695,6 +697,8 @@ static DWORD WINAPI custom_client_thread(void *arg)
         return GetLastError();
     }

+    LeaveCriticalSection(&msi_custom_action_cs);
+
     if (DuplicateHandle(process, (HANDLE)(DWORD_PTR)thread64, GetCurrentProcess(),
         &thread, 0, FALSE, DUPLICATE_SAME_ACCESS | DUPLICATE_CLOSE_SOURCE))
     {