From bf6d09a87853614062c56b54e86d44ee0a9f7549 Mon Sep 17 00:00:00 2001
From: Leonid Yuriev <leo@yuriev.ru>
Date: Mon, 9 Dec 2019 10:59:57 +0300
Subject: [PATCH] mdbx-windows: use manual-reset events to avoid non-atomic
 races.

Change-Id: I93b9f114c7c1a205dba18dcc363cf4ba8a27d7e0
---
 src/elements/core.c | 26 +++++++++++++++++---------
 src/elements/osal.c |  9 ++++++---
 2 files changed, 23 insertions(+), 12 deletions(-)

diff --git a/src/elements/core.c b/src/elements/core.c
index cc78f558..5ad296a1 100644
--- a/src/elements/core.c
+++ b/src/elements/core.c
@@ -13851,22 +13851,26 @@ static THREAD_RESULT __cold THREAD_CALL mdbx_env_copythr(void *arg) {
   mdbx_copy *my = arg;
   uint8_t *ptr;
   int toggle = 0;
-  int rc;
 
   mdbx_condmutex_lock(&my->mc_condmutex);
   while (!my->mc_error) {
-    while (!my->mc_new)
-      mdbx_condmutex_wait(&my->mc_condmutex);
+    while (!my->mc_new && !my->mc_error) {
+      int err = mdbx_condmutex_wait(&my->mc_condmutex);
+      if (err != MDBX_SUCCESS) {
+        my->mc_error = err;
+        goto bailout;
+      }
+    }
     if (my->mc_new == 0 + MDBX_EOF) /* 0 buffers, just EOF */
       break;
     size_t wsize = my->mc_wlen[toggle];
     ptr = my->mc_wbuf[toggle];
   again:
     if (wsize > 0 && !my->mc_error) {
-      rc = mdbx_write(my->mc_fd, ptr, wsize);
-      if (rc != MDBX_SUCCESS) {
-        my->mc_error = rc;
-        break;
+      int err = mdbx_write(my->mc_fd, ptr, wsize);
+      if (err != MDBX_SUCCESS) {
+        my->mc_error = err;
+        goto bailout;
       }
     }
 
@@ -13883,6 +13887,7 @@ static THREAD_RESULT __cold THREAD_CALL mdbx_env_copythr(void *arg) {
     my->mc_new--;
     mdbx_condmutex_signal(&my->mc_condmutex);
   }
+bailout:
   mdbx_condmutex_unlock(&my->mc_condmutex);
   return (THREAD_RESULT)0;
 }
@@ -13895,8 +13900,11 @@ static int __cold mdbx_env_cthr_toggle(mdbx_copy *my, int adjust) {
   mdbx_condmutex_lock(&my->mc_condmutex);
   my->mc_new += (short)adjust;
   mdbx_condmutex_signal(&my->mc_condmutex);
-  while (my->mc_new & 2) /* both buffers in use */
-    mdbx_condmutex_wait(&my->mc_condmutex);
+  while (!my->mc_error && (my->mc_new & 2) /* both buffers in use */) {
+    int err = mdbx_condmutex_wait(&my->mc_condmutex);
+    if (err != MDBX_SUCCESS)
+      my->mc_error = err;
+  }
   mdbx_condmutex_unlock(&my->mc_condmutex);
 
   my->mc_toggle ^= (adjust & 1);
diff --git a/src/elements/osal.c b/src/elements/osal.c
index e16c9537..49866799 100644
--- a/src/elements/osal.c
+++ b/src/elements/osal.c
@@ -371,11 +371,11 @@ MDBX_INTERNAL_FUNC int mdbx_condmutex_init(mdbx_condmutex_t *condmutex) {
 #if defined(_WIN32) || defined(_WIN64)
   int rc = MDBX_SUCCESS;
   condmutex->event = NULL;
-  condmutex->mutex = CreateMutex(NULL, FALSE, NULL);
+  condmutex->mutex = CreateMutexW(NULL, FALSE, NULL);
   if (!condmutex->mutex)
     return GetLastError();
 
-  condmutex->event = CreateEvent(NULL, FALSE, FALSE, NULL);
+  condmutex->event = CreateEventW(NULL, TRUE, FALSE, NULL);
   if (!condmutex->event) {
     rc = GetLastError();
     (void)CloseHandle(condmutex->mutex);
@@ -459,8 +459,11 @@ MDBX_INTERNAL_FUNC int mdbx_condmutex_wait(mdbx_condmutex_t *condmutex) {
 #if defined(_WIN32) || defined(_WIN64)
   DWORD code =
       SignalObjectAndWait(condmutex->mutex, condmutex->event, INFINITE, FALSE);
-  if (code == WAIT_OBJECT_0)
+  if (code == WAIT_OBJECT_0) {
     code = WaitForSingleObject(condmutex->mutex, INFINITE);
+    if (code == WAIT_OBJECT_0)
+      return ResetEvent(condmutex->event) ? MDBX_SUCCESS : GetLastError();
+  }
   return waitstatus2errcode(code);
 #else
   return pthread_cond_wait(&condmutex->cond, &condmutex->mutex);