libmdbx:

- fix for a possible crash after database compaction;
- merge with master

19 files changed, 531 insertions, 257 deletions

diff --git a/libs/libmdbx/src/README.md b/libs/libmdbx/src/README.md
index 7c07de316e..a2a6ab7ac3 100644
--- a/libs/libmdbx/src/README.md
+++ b/libs/libmdbx/src/README.md
@@ -32,7 +32,12 @@ libmdbx
    6. [Asynchronous lazy data flushing](https://sites.fas.harvard.edu/~cs265/papers/kathuria-2008.pdf) to disk(s);
    7. etc...
 
-Don't miss [Java Native Interface](https://github.com/castortech/mdbxjni) by [Castor Technologies](https://castortech.com/).
+Don't miss libmdbx for other runtimes.
+
+| Runtime  | GitHub | Author |
+| ------------- | ------------- | ------------- |
+| JVM   | [mdbxjni](https://github.com/castortech/mdbxjni) | [Castor Technologies](https://castortech.com/) |
+| .NET  | [mdbx.NET](https://github.com/wangjia184/mdbx.NET)  | [Jerry Wang](https://github.com/wangjia184) |
 
 -----
 
diff --git a/libs/libmdbx/src/dll.vcxproj b/libs/libmdbx/src/dll.vcxproj
index 746de67bd9..812e1e65a8 100644
--- a/libs/libmdbx/src/dll.vcxproj
+++ b/libs/libmdbx/src/dll.vcxproj
@@ -73,6 +73,7 @@
     <TargetName>mdbx</TargetName>
     <OutDir>$(SolutionDir)$(Platform)\$(Configuration)\</OutDir>
     <IntDir>$(SolutionDir)$(Platform)\$(Configuration)\$(ProjectName)\</IntDir>
+    <CustomBuildBeforeTargets>PreLinkEvent</CustomBuildBeforeTargets>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
     <LinkIncremental>false</LinkIncremental>
@@ -80,22 +81,25 @@
     <TargetName>mdbx</TargetName>
     <OutDir>$(SolutionDir)$(Platform)\$(Configuration)\</OutDir>
     <IntDir>$(SolutionDir)$(Platform)\$(Configuration)\$(ProjectName)\</IntDir>
+    <CustomBuildBeforeTargets>PreLinkEvent</CustomBuildBeforeTargets>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">
     <LinkIncremental>true</LinkIncremental>
     <TargetName>mdbx</TargetName>
     <OutDir>$(SolutionDir)$(Platform)\$(Configuration)\</OutDir>
     <IntDir>$(SolutionDir)$(Platform)\$(Configuration)\$(ProjectName)\</IntDir>
+    <CustomBuildBeforeTargets>PreLinkEvent</CustomBuildBeforeTargets>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'">
     <LinkIncremental>false</LinkIncremental>
     <TargetName>mdbx</TargetName>
     <OutDir>$(SolutionDir)$(Platform)\$(Configuration)\</OutDir>
     <IntDir>$(SolutionDir)$(Platform)\$(Configuration)\$(ProjectName)\</IntDir>
+    <CustomBuildBeforeTargets>PreLinkEvent</CustomBuildBeforeTargets>
   </PropertyGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
     <ClCompile>
-      <PreprocessorDefinitions>WIN32;_DEBUG;_WINDOWS;_USRDLL;LIBMDBX_EXPORTS;%(PreprocessorDefinitions);MDBX_DEBUG=1</PreprocessorDefinitions>
+      <PreprocessorDefinitions>WIN32;_DEBUG;_WINDOWS;_USRDLL;LIBMDBX_EXPORTS;MDBX_BUILD_DLL;MDBX_AVOID_CRT;%(PreprocessorDefinitions);MDBX_DEBUG=1</PreprocessorDefinitions>
       <RuntimeLibrary>MultiThreadedDebugDLL</RuntimeLibrary>
       <WarningLevel>EnableAllWarnings</WarningLevel>
       <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
@@ -107,11 +111,18 @@
       <TargetMachine>MachineX86</TargetMachine>
       <GenerateDebugInformation>true</GenerateDebugInformation>
       <SubSystem>Windows</SubSystem>
+      <AdditionalDependencies>ntdll.lib;$(IntermediateOutputPath)mdbx_ntdll_extra.lib;kernel32.lib;advapi32.lib;%(AdditionalDependencies)</AdditionalDependencies>
     </Link>
+    <CustomBuildStep>
+      <Message>Generate fake-library mdbx_ntdll_extra.lib for $(PlatformTarget)</Message>
+      <Outputs>$(IntermediateOutputPath)mdbx_ntdll_extra.lib</Outputs>
+      <Inputs>$(ProjectDir)src/ntdll.def</Inputs>
+      <Command>lib.exe /def:%(Inputs) /out:%(Outputs) /machine:$(PlatformTarget)</Command>
+    </CustomBuildStep>
   </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
     <ClCompile>
-      <PreprocessorDefinitions>WIN32;NDEBUG;_WINDOWS;_USRDLL;LIBMDBX_EXPORTS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <PreprocessorDefinitions>WIN32;NDEBUG;_WINDOWS;_USRDLL;LIBMDBX_EXPORTS;MDBX_BUILD_DLL;MDBX_AVOID_CRT;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <RuntimeLibrary>MultiThreadedDLL</RuntimeLibrary>
       <WarningLevel>EnableAllWarnings</WarningLevel>
       <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
@@ -122,6 +133,9 @@
       <FavorSizeOrSpeed>Size</FavorSizeOrSpeed>
       <OmitFramePointers>true</OmitFramePointers>
       <WholeProgramOptimization>true</WholeProgramOptimization>
+      <FunctionLevelLinking>true</FunctionLevelLinking>
+      <BufferSecurityCheck>false</BufferSecurityCheck>
+      <AssemblerOutput>All</AssemblerOutput>
     </ClCompile>
     <Link>
       <TargetMachine>MachineX86</TargetMachine>
@@ -130,7 +144,15 @@
       <EnableCOMDATFolding>true</EnableCOMDATFolding>
       <OptimizeReferences>true</OptimizeReferences>
       <LinkTimeCodeGeneration>UseLinkTimeCodeGeneration</LinkTimeCodeGeneration>
+      <AdditionalDependencies>ntdll.lib;$(IntermediateOutputPath)mdbx_ntdll_extra.lib;kernel32.lib;advapi32.lib;%(AdditionalDependencies)</AdditionalDependencies>
+      <IgnoreAllDefaultLibraries>true</IgnoreAllDefaultLibraries>
     </Link>
+    <CustomBuildStep>
+      <Message>Generate fake-library mdbx_ntdll_extra.lib for $(PlatformTarget)</Message>
+      <Outputs>$(IntermediateOutputPath)mdbx_ntdll_extra.lib</Outputs>
+      <Inputs>$(ProjectDir)src/ntdll.def</Inputs>
+      <Command>lib.exe /def:%(Inputs) /out:%(Outputs) /machine:$(PlatformTarget)</Command>
+    </CustomBuildStep>
   </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">
     <ClCompile>
@@ -140,15 +162,24 @@
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">
     <ClCompile>
       <WarningLevel>EnableAllWarnings</WarningLevel>
-      <PreprocessorDefinitions>WIN64;_DEBUG;_WINDOWS;_USRDLL;LIBMDBX_EXPORTS;%(PreprocessorDefinitions);MDBX_DEBUG=1</PreprocessorDefinitions>
+      <PreprocessorDefinitions>WIN64;_DEBUG;_WINDOWS;_USRDLL;LIBMDBX_EXPORTS;MDBX_BUILD_DLL;MDBX_AVOID_CRT;%(PreprocessorDefinitions);MDBX_DEBUG=1</PreprocessorDefinitions>
       <RuntimeLibrary>MultiThreadedDebugDLL</RuntimeLibrary>
       <StringPooling>true</StringPooling>
       <TreatWarningAsError>true</TreatWarningAsError>
     </ClCompile>
+    <Link>
+      <AdditionalDependencies>ntdll.lib;$(IntermediateOutputPath)mdbx_ntdll_extra.lib;kernel32.lib;advapi32.lib;%(AdditionalDependencies)</AdditionalDependencies>
+    </Link>
+    <CustomBuildStep>
+      <Message>Generate fake-library mdbx_ntdll_extra.lib for $(PlatformTarget)</Message>
+      <Outputs>$(IntermediateOutputPath)mdbx_ntdll_extra.lib</Outputs>
+      <Inputs>$(ProjectDir)src/ntdll.def</Inputs>
+      <Command>lib.exe /def:%(Inputs) /out:%(Outputs) /machine:$(PlatformTarget)</Command>
+    </CustomBuildStep>
   </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'">
     <ClCompile>
-      <PreprocessorDefinitions>WIN64;NDEBUG;_WINDOWS;_USRDLL;LIBMDBX_EXPORTS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <PreprocessorDefinitions>WIN64;NDEBUG;_WINDOWS;_USRDLL;LIBMDBX_EXPORTS;MDBX_BUILD_DLL;MDBX_AVOID_CRT;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <RuntimeLibrary>MultiThreadedDLL</RuntimeLibrary>
       <StringPooling>true</StringPooling>
       <Optimization>Full</Optimization>
@@ -158,10 +189,21 @@
       <OmitFramePointers>true</OmitFramePointers>
       <WholeProgramOptimization>true</WholeProgramOptimization>
       <WarningLevel>EnableAllWarnings</WarningLevel>
+      <FunctionLevelLinking>true</FunctionLevelLinking>
+      <BufferSecurityCheck>false</BufferSecurityCheck>
+      <AssemblerOutput>All</AssemblerOutput>
     </ClCompile>
     <Link>
       <LinkTimeCodeGeneration>UseLinkTimeCodeGeneration</LinkTimeCodeGeneration>
+      <AdditionalDependencies>ntdll.lib;$(IntermediateOutputPath)mdbx_ntdll_extra.lib;kernel32.lib;advapi32.lib;%(AdditionalDependencies)</AdditionalDependencies>
+      <IgnoreAllDefaultLibraries>true</IgnoreAllDefaultLibraries>
     </Link>
+    <CustomBuildStep>
+      <Message>Generate fake-library mdbx_ntdll_extra.lib for $(PlatformTarget)</Message>
+      <Outputs>$(IntermediateOutputPath)mdbx_ntdll_extra.lib</Outputs>
+      <Inputs>$(ProjectDir)src/ntdll.def</Inputs>
+      <Command>lib.exe /def:%(Inputs) /out:%(Outputs) /machine:$(PlatformTarget)</Command>
+    </CustomBuildStep>
   </ItemDefinitionGroup>
   <ItemGroup>
     <ClCompile Include="src\lck-windows.c" />
diff --git a/libs/libmdbx/src/mdbx.h b/libs/libmdbx/src/mdbx.h
index 283f595df6..120d6847e4 100644
--- a/libs/libmdbx/src/mdbx.h
+++ b/libs/libmdbx/src/mdbx.h
@@ -212,6 +212,7 @@ extern LIBMDBX_API const mdbx_version_info mdbx_version;
 extern LIBMDBX_API const mdbx_build_info mdbx_build;
 
 #if defined(_WIN32) || defined(_WIN64)
+#ifndef MDBX_BUILD_DLL
 
 /* Dll initialization callback for ability to dynamically load MDBX DLL by
  * LoadLibrary() on Windows versions before Windows Vista. This function MUST be
@@ -227,6 +228,7 @@ extern LIBMDBX_API const mdbx_build_info mdbx_build;
 void LIBMDBX_API NTAPI mdbx_dll_callback(PVOID module, DWORD reason,
                                          PVOID reserved);
 #endif /* MDBX_CONFIG_MANUAL_TLS_CALLBACK */
+#endif /* MDBX_BUILD_DLL */
 #endif /* Windows */
 
 /* The name of the lock file in the DB environment */
diff --git a/libs/libmdbx/src/src/bits.h b/libs/libmdbx/src/src/bits.h
index d1c27bc5ab..3d3e392180 100644
--- a/libs/libmdbx/src/src/bits.h
+++ b/libs/libmdbx/src/src/bits.h
@@ -476,10 +476,10 @@ typedef struct MDBX_lockinfo {
    (uint16_t)(MDBX_LOCKINFO_WHOLE_SIZE + MDBX_CACHELINE_SIZE - 1))
 
 #define MDBX_DATA_MAGIC ((MDBX_MAGIC << 8) + MDBX_DATA_VERSION)
-#define MDBX_DATA_DEBUG ((MDBX_MAGIC << 8) + 255)
+#define MDBX_DATA_MAGIC_DEVEL ((MDBX_MAGIC << 8) + 255)
 
 #define MDBX_LOCK_MAGIC ((MDBX_MAGIC << 8) + MDBX_LOCK_VERSION)
-#define MDBX_LOCK_DEBUG ((MDBX_MAGIC << 8) + 255)
+#define MDBX_LOCK_MAGIC_DEVEL ((MDBX_MAGIC << 8) + 255)
 
 #ifndef MDBX_ASSUME_MALLOC_OVERHEAD
 #define MDBX_ASSUME_MALLOC_OVERHEAD (sizeof(void *) * 2u)
@@ -870,6 +870,9 @@ void mdbx_panic(const char *fmt, ...)
 #endif /* NDEBUG */
 #endif /* MDBX_DEBUG */
 
+LIBMDBX_API void mdbx_assert_fail(const MDBX_env *env, const char *msg,
+                                  const char *func, int line);
+
 #define mdbx_print(fmt, ...)                                                   \
   mdbx_debug_log(MDBX_DBG_PRINT, NULL, 0, fmt, ##__VA_ARGS__)
 
@@ -969,6 +972,9 @@ void mdbx_panic(const char *fmt, ...)
 /* assert(3) variant in transaction context */
 #define mdbx_tassert(txn, expr) mdbx_assert((txn)->mt_env, expr)
 
+#undef assert
+#define assert(expr) mdbx_assert(NULL, expr)
+
 /*----------------------------------------------------------------------------*/
 /* Internal prototypes */
 
diff --git a/libs/libmdbx/src/src/lck-posix.c b/libs/libmdbx/src/src/lck-posix.c
index 0aa9d85078..9743955311 100644
--- a/libs/libmdbx/src/src/lck-posix.c
+++ b/libs/libmdbx/src/src/lck-posix.c
@@ -126,7 +126,8 @@ int mdbx_rpid_check(MDBX_env *env, mdbx_pid_t pid) {
 
 /*---------------------------------------------------------------------------*/
 
-static int mdbx_mutex_failed(MDBX_env *env, pthread_mutex_t *mutex, int rc);
+static int mdbx_mutex_failed(MDBX_env *env, pthread_mutex_t *mutex,
+                             const int rc);
 
 int __cold mdbx_lck_init(MDBX_env *env) {
   pthread_mutexattr_t ma;
@@ -297,9 +298,10 @@ int __cold mdbx_lck_seize(MDBX_env *env) {
 #endif
 
 static int __cold mdbx_mutex_failed(MDBX_env *env, pthread_mutex_t *mutex,
-                                    int rc) {
+                                    const int err) {
+  int rc = err;
 #if MDBX_USE_ROBUST
-  if (rc == EOWNERDEAD) {
+  if (err == EOWNERDEAD) {
     /* We own the mutex. Clean up after dead previous owner. */
 
     int rlocked = (env->me_lck && mutex == &env->me_lck->mti_rmutex);
@@ -331,10 +333,8 @@ static int __cold mdbx_mutex_failed(MDBX_env *env, pthread_mutex_t *mutex,
   }
 #endif /* MDBX_USE_ROBUST */
 
-  mdbx_error("mutex (un)lock failed, %s", mdbx_strerror(rc));
-  if (rc != EDEADLK) {
+  mdbx_error("mutex (un)lock failed, %s", mdbx_strerror(err));
+  if (rc != EDEADLK)
     env->me_flags |= MDBX_FATAL_ERROR;
-    rc = MDBX_PANIC;
-  }
   return rc;
 }
diff --git a/libs/libmdbx/src/src/lck-windows.c b/libs/libmdbx/src/src/lck-windows.c
index 7da0755916..c019a6d547 100644
--- a/libs/libmdbx/src/src/lck-windows.c
+++ b/libs/libmdbx/src/src/lck-windows.c
@@ -26,11 +26,29 @@
 
 static void mdbx_winnt_import(void);
 
+#ifdef MDBX_BUILD_DLL
+/* DEBUG/CHECKED builds still require MSVC's CRT for runtime checks.
+ *
+ * Therefore we don't define dll's entry point for debug/checked builds by MSVC.
+ * In this case MSVC's will automatically use DllMainCRTStartup() from CRT
+ * library, which also automatically call DllMain() from our mdbx.dll
+ *
+ * On the other side, for RELEASE builds
+ * we explicitly define DllMain() as the entry point and don't linking with
+ * any CRT libraries (IgnoreAllDefaultLibraries = Yes). */
+#if !defined(_MSC_VER) || defined(NDEBUG)
+#pragma comment(linker, "/ENTRY:DllMain")
+#endif
+
+BOOL APIENTRY DllMain(HANDLE module, DWORD reason, LPVOID reserved)
+#else
 #if !MDBX_CONFIG_MANUAL_TLS_CALLBACK
 static
 #endif /* !MDBX_CONFIG_MANUAL_TLS_CALLBACK */
     void NTAPI
-    mdbx_dll_callback(PVOID module, DWORD reason, PVOID reserved) {
+    mdbx_dll_callback(PVOID module, DWORD reason, PVOID reserved)
+#endif /* MDBX_BUILD_DLL */
+{
   (void)reserved;
   switch (reason) {
   case DLL_PROCESS_ATTACH:
@@ -47,9 +65,12 @@ static
     mdbx_rthc_thread_dtor(module);
     break;
   }
+#ifdef MDBX_BUILD_DLL
+  return TRUE;
+#endif
 }
 
-#if !MDBX_CONFIG_MANUAL_TLS_CALLBACK
+#if !defined(MDBX_BUILD_DLL) && !MDBX_CONFIG_MANUAL_TLS_CALLBACK
 /* *INDENT-OFF* */
 /* clang-format off */
 #if defined(_MSC_VER)
@@ -87,7 +108,7 @@ static
 #endif
 /* *INDENT-ON* */
 /* clang-format on */
-#endif /* !MDBX_CONFIG_MANUAL_TLS_CALLBACK */
+#endif /* !defined(MDBX_BUILD_DLL) && !MDBX_CONFIG_MANUAL_TLS_CALLBACK */
 
 /*----------------------------------------------------------------------------*/
 
@@ -191,12 +212,12 @@ static int suspend_and_append(mdbx_handle_array_t **array,
                               const DWORD ThreadId) {
   const unsigned limit = (*array)->limit;
   if ((*array)->count == limit) {
-    void *ptr = realloc((limit > ARRAY_LENGTH((*array)->handles))
-                            ? *array
-                            : /* don't free initial array on the stack */ NULL,
-                        sizeof(mdbx_handle_array_t) +
-                            sizeof(HANDLE) *
-                                (limit * 2 - ARRAY_LENGTH((*array)->handles)));
+    void *ptr = mdbx_realloc(
+        (limit > ARRAY_LENGTH((*array)->handles))
+            ? *array
+            : /* don't free initial array on the stack */ NULL,
+        sizeof(mdbx_handle_array_t) +
+            sizeof(HANDLE) * (limit * 2 - ARRAY_LENGTH((*array)->handles)));
     if (!ptr)
       return MDBX_ENOMEM;
     if (limit == ARRAY_LENGTH((*array)->handles))
@@ -205,12 +226,19 @@ static int suspend_and_append(mdbx_handle_array_t **array,
     (*array)->limit = limit * 2;
   }
 
-  HANDLE hThread = OpenThread(THREAD_SUSPEND_RESUME, FALSE, ThreadId);
+  HANDLE hThread = OpenThread(THREAD_SUSPEND_RESUME | THREAD_QUERY_INFORMATION,
+                              FALSE, ThreadId);
   if (hThread == NULL)
     return GetLastError();
+
   if (SuspendThread(hThread) == -1) {
+    int err = GetLastError();
+    DWORD ExitCode;
+    if (err == /* workaround for Win10 UCRT bug */ ERROR_ACCESS_DENIED ||
+        !GetExitCodeThread(hThread, &ExitCode) || ExitCode != STILL_ACTIVE)
+      err = MDBX_SUCCESS;
     CloseHandle(hThread);
-    return GetLastError();
+    return err;
   }
 
   (*array)->handles[(*array)->count++] = hThread;
@@ -295,9 +323,15 @@ int mdbx_suspend_threads_before_remap(MDBX_env *env,
 int mdbx_resume_threads_after_remap(mdbx_handle_array_t *array) {
   int rc = MDBX_SUCCESS;
   for (unsigned i = 0; i < array->count; ++i) {
-    if (ResumeThread(array->handles[i]) == -1)
-      rc = GetLastError();
-    CloseHandle(array->handles[i]);
+    const HANDLE hThread = array->handles[i];
+    if (ResumeThread(hThread) == -1) {
+      const int err = GetLastError();
+      DWORD ExitCode;
+      if (err != /* workaround for Win10 UCRT bug */ ERROR_ACCESS_DENIED &&
+          GetExitCodeThread(hThread, &ExitCode) && ExitCode == STILL_ACTIVE)
+        rc = err;
+    }
+    CloseHandle(hThread);
   }
   return rc;
 }
diff --git a/libs/libmdbx/src/src/mdbx.c b/libs/libmdbx/src/src/mdbx.c
index 0d06f1a191..b0111895bf 100644
--- a/libs/libmdbx/src/src/mdbx.c
+++ b/libs/libmdbx/src/src/mdbx.c
@@ -1,4 +1,4 @@
-/*
+/*
  * Copyright 2015-2018 Leonid Yuriev <leo@yuriev.ru>
  * and other libmdbx authors: please see AUTHORS file.
  * All rights reserved.
@@ -40,9 +40,6 @@
 /*----------------------------------------------------------------------------*/
 /* Internal inlines */
 
-#undef assert
-#define assert(expr) mdbx_assert(NULL, expr)
-
 static __inline bool mdbx_is_power2(size_t x) { return (x & (x - 1)) == 0; }
 
 static __inline size_t mdbx_roundup2(size_t value, size_t granularity) {
@@ -531,7 +528,7 @@ __cold void mdbx_rthc_global_dtor(void) {
 
   rthc_limit = rthc_count = 0;
   if (rthc_table != rthc_table_static)
-    free(rthc_table);
+    mdbx_free(rthc_table);
   rthc_table = nullptr;
   mdbx_rthc_unlock();
 
@@ -560,8 +557,8 @@ __cold int mdbx_rthc_alloc(mdbx_thread_key_t *key, MDBX_reader *begin,
              rthc_limit);
   if (rthc_count == rthc_limit) {
     rthc_entry_t *new_table =
-        realloc((rthc_table == rthc_table_static) ? nullptr : rthc_table,
-                sizeof(rthc_entry_t) * rthc_limit * 2);
+        mdbx_realloc((rthc_table == rthc_table_static) ? nullptr : rthc_table,
+                     sizeof(rthc_entry_t) * rthc_limit * 2);
     if (new_table == nullptr) {
       rc = MDBX_ENOMEM;
       goto bailout;
@@ -609,7 +606,7 @@ __cold void mdbx_rthc_remove(const mdbx_thread_key_t key) {
       if (--rthc_count > 0)
         rthc_table[i] = rthc_table[rthc_count];
       else if (rthc_table != rthc_table_static) {
-        free(rthc_table);
+        mdbx_free(rthc_table);
         rthc_table = rthc_table_static;
         rthc_limit = RTHC_INITIAL_LIMIT;
       }
@@ -641,7 +638,7 @@ static __inline pgno_t bytes2pnl(const size_t bytes) {
 
 static MDBX_PNL mdbx_pnl_alloc(size_t size) {
   const size_t bytes = pnl2bytes(size);
-  MDBX_PNL pl = malloc(bytes);
+  MDBX_PNL pl = mdbx_malloc(bytes);
   if (likely(pl)) {
 #if __GLIBC_PREREQ(2, 12)
     const size_t bytes = malloc_usable_size(pl);
@@ -656,7 +653,7 @@ static MDBX_PNL mdbx_pnl_alloc(size_t size) {
 
 static void mdbx_pnl_free(MDBX_PNL pl) {
   if (likely(pl))
-    free(pl - 1);
+    mdbx_free(pl - 1);
 }
 
 /* Shrink the PNL to the default size if it has grown larger */
@@ -668,7 +665,7 @@ static void mdbx_pnl_shrink(MDBX_PNL *ppl) {
   if (unlikely(MDBX_PNL_ALLOCLEN(*ppl) >
                MDBX_PNL_INITIAL + MDBX_CACHELINE_SIZE / sizeof(pgno_t))) {
     const size_t bytes = pnl2bytes(MDBX_PNL_INITIAL);
-    MDBX_PNL pl = realloc(*ppl - 1, bytes);
+    MDBX_PNL pl = mdbx_realloc(*ppl - 1, bytes);
     if (likely(pl)) {
 #if __GLIBC_PREREQ(2, 12)
       const size_t bytes = malloc_usable_size(pl);
@@ -694,7 +691,7 @@ static int mdbx_pnl_reserve(MDBX_PNL *ppl, const size_t wanna) {
                           ? wanna + wanna - allocated
                           : MDBX_PNL_MAX;
   const size_t bytes = pnl2bytes(size);
-  MDBX_PNL pl = realloc(*ppl - 1, bytes);
+  MDBX_PNL pl = mdbx_realloc(*ppl - 1, bytes);
   if (likely(pl)) {
 #if __GLIBC_PREREQ(2, 12)
     const size_t bytes = malloc_usable_size(pl);
@@ -935,7 +932,7 @@ static __inline size_t bytes2txl(const size_t bytes) {
 
 static MDBX_TXL mdbx_txl_alloc(void) {
   const size_t bytes = txl2bytes(MDBX_TXL_INITIAL);
-  MDBX_TXL tl = malloc(bytes);
+  MDBX_TXL tl = mdbx_malloc(bytes);
   if (likely(tl)) {
 #if __GLIBC_PREREQ(2, 12)
     const size_t bytes = malloc_usable_size(tl);
@@ -950,7 +947,7 @@ static MDBX_TXL mdbx_txl_alloc(void) {
 
 static void mdbx_txl_free(MDBX_TXL tl) {
   if (likely(tl))
-    free(tl - 1);
+    mdbx_free(tl - 1);
 }
 
 static int mdbx_txl_reserve(MDBX_TXL *ptl, const size_t wanna) {
@@ -967,7 +964,7 @@ static int mdbx_txl_reserve(MDBX_TXL *ptl, const size_t wanna) {
                           ? wanna + wanna - allocated
                           : MDBX_TXL_MAX;
   const size_t bytes = txl2bytes(size);
-  MDBX_TXL tl = realloc(*ptl - 1, bytes);
+  MDBX_TXL tl = mdbx_realloc(*ptl - 1, bytes);
   if (likely(tl)) {
 #if __GLIBC_PREREQ(2, 12)
     const size_t bytes = malloc_usable_size(tl);
@@ -1328,7 +1325,7 @@ const char *__cold mdbx_strerror_r(int errnum, char *buf, size_t buflen) {
   if (!msg) {
     if (!buflen || buflen > INT_MAX)
       return NULL;
-#ifdef _MSC_VER
+#if defined(_WIN32) || defined(_WIN64)
     size_t size = FormatMessageA(
         FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS, NULL,
         errnum, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), buf, (DWORD)buflen,
@@ -1357,7 +1354,7 @@ const char *__cold mdbx_strerror_r(int errnum, char *buf, size_t buflen) {
 const char *__cold mdbx_strerror(int errnum) {
   const char *msg = __mdbx_strerr(errnum);
   if (!msg) {
-#ifdef _MSC_VER
+#if defined(_WIN32) || defined(_WIN64)
     static char buffer[1024];
     size_t size = FormatMessageA(
         FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS, NULL,
@@ -1389,6 +1386,28 @@ void __cold mdbx_debug_log(int type, const char *function, int line,
   if (mdbx_debug_logger)
     mdbx_debug_logger(type, function, line, fmt, args);
   else {
+#if defined(_WIN32) || defined(_WIN64)
+    if (IsDebuggerPresent()) {
+      int prefix_len = 0;
+      char *prefix = nullptr;
+      if (function && line > 0)
+        prefix_len = mdbx_asprintf(&prefix, "%s:%d ", function, line);
+      else if (function)
+        prefix_len = mdbx_asprintf(&prefix, "%s: ", function);
+      else if (line > 0)
+        prefix_len = mdbx_asprintf(&prefix, "%d: ", line);
+      if (prefix_len > 0 && prefix) {
+        OutputDebugStringA(prefix);
+        mdbx_free(prefix);
+      }
+      char *msg = nullptr;
+      int msg_len = mdbx_vasprintf(&msg, fmt, args);
+      if (msg_len > 0 && msg) {
+        OutputDebugStringA(msg);
+        mdbx_free(msg);
+      }
+    }
+#else
     if (function && line > 0)
       fprintf(stderr, "%s:%d ", function, line);
     else if (function)
@@ -1397,6 +1416,7 @@ void __cold mdbx_debug_log(int type, const char *function, int line,
       fprintf(stderr, "%d: ", line);
     vfprintf(stderr, fmt, args);
     fflush(stderr);
+#endif
   }
   va_end(args);
 }
@@ -1577,7 +1597,7 @@ static MDBX_page *mdbx_page_malloc(MDBX_txn *txn, unsigned num) {
     env->me_dpages = np->mp_next;
   } else {
     size = pgno2bytes(env, num);
-    np = malloc(size);
+    np = mdbx_malloc(size);
     if (unlikely(!np)) {
       txn->mt_flags |= MDBX_TXN_ERROR;
       return np;
@@ -1615,7 +1635,7 @@ static void mdbx_dpage_free(MDBX_env *env, MDBX_page *dp, unsigned pages) {
   } else {
     /* large pages just get freed directly */
     VALGRIND_MEMPOOL_FREE(env, dp);
-    free(dp);
+    mdbx_free(dp);
   }
 }
 
@@ -1639,7 +1659,9 @@ static size_t bytes_align2os_bytes(const MDBX_env *env, size_t bytes) {
 
 static void __cold mdbx_kill_page(MDBX_env *env, MDBX_page *mp) {
   const size_t len = env->me_psize - PAGEHDRSZ;
-  void *ptr = (env->me_flags & MDBX_WRITEMAP) ? &mp->mp_data : alloca(len);
+  void *ptr = (env->me_flags & MDBX_WRITEMAP)
+                  ? &mp->mp_data
+                  : (void *)((uint8_t *)env->me_pbuf + env->me_psize);
   memset(ptr, 0x6F /* 'o', 111 */, len);
   if (ptr != &mp->mp_data)
     (void)mdbx_pwrite(env->me_fd, ptr, len,
@@ -2273,18 +2295,20 @@ bailout:
             VALGRIND_CREATE_BLOCK(env->me_map, env->me_mapsize, "mdbx");
     }
 #endif
-  } else if (rc != MDBX_RESULT_TRUE) {
-    mdbx_error("failed resize datafile/mapping: "
-               "present %" PRIuPTR " -> %" PRIuPTR ", "
-               "limit %" PRIuPTR " -> %" PRIuPTR ", errcode %d",
-               env->me_dbgeo.now, size_bytes, env->me_dbgeo.upper, limit_bytes,
-               rc);
   } else {
-    mdbx_notice("unable resize datafile/mapping: "
-                "present %" PRIuPTR " -> %" PRIuPTR ", "
-                "limit %" PRIuPTR " -> %" PRIuPTR ", errcode %d",
-                env->me_dbgeo.now, size_bytes, env->me_dbgeo.upper, limit_bytes,
-                rc);
+    if (rc != MDBX_RESULT_TRUE) {
+      mdbx_error("failed resize datafile/mapping: "
+                 "present %" PRIuPTR " -> %" PRIuPTR ", "
+                 "limit %" PRIuPTR " -> %" PRIuPTR ", errcode %d",
+                 env->me_dbgeo.now, size_bytes, env->me_dbgeo.upper,
+                 limit_bytes, rc);
+    } else {
+      mdbx_notice("unable resize datafile/mapping: "
+                  "present %" PRIuPTR " -> %" PRIuPTR ", "
+                  "limit %" PRIuPTR " -> %" PRIuPTR ", errcode %d",
+                  env->me_dbgeo.now, size_bytes, env->me_dbgeo.upper,
+                  limit_bytes, rc);
+    }
     if (!env->me_dxb_mmap.address) {
       env->me_flags |= MDBX_FATAL_ERROR;
       if (env->me_txn)
@@ -2299,7 +2323,7 @@ bailout:
   if (suspended) {
     err = mdbx_resume_threads_after_remap(suspended);
     if (suspended != &array_onstack)
-      free(suspended);
+      mdbx_free(suspended);
   }
 #else
   int err = mdbx_fastmutex_release(&env->me_remap_guard);
@@ -3025,7 +3049,7 @@ static int mdbx_cursor_shadow(MDBX_txn *src, MDBX_txn *dst) {
       if (mc->mc_xcursor)
         size += sizeof(MDBX_xcursor);
       for (; mc; mc = bk->mc_next) {
-        bk = malloc(size);
+        bk = mdbx_malloc(size);
         if (unlikely(!bk))
           return MDBX_ENOMEM;
         *bk = *mc;
@@ -3082,11 +3106,11 @@ static void mdbx_cursors_eot(MDBX_txn *txn, unsigned merge) {
             *mx = *(MDBX_xcursor *)(bk + 1);
         }
         bk->mc_signature = 0;
-        free(bk);
+        mdbx_free(bk);
       }
       if (stage == MDBX_MC_WAIT4EOT) {
         mc->mc_signature = 0;
-        free(mc);
+        mdbx_free(mc);
       } else {
         mc->mc_signature = MDBX_MC_READY4CLOSE;
         mc->mc_flags = 0 /* reset C_UNTRACK */;
@@ -3139,6 +3163,16 @@ static int mdbx_txn_renew0(MDBX_txn *txn, unsigned flags) {
       rc = mdbx_rdt_lock(env);
       if (unlikely(MDBX_IS_ERROR(rc)))
         return rc;
+      if (unlikely(env->me_flags & MDBX_FATAL_ERROR)) {
+        mdbx_rdt_unlock(env);
+        return MDBX_PANIC;
+      }
+#if defined(_WIN32) || defined(_WIN64)
+      if (unlikely(!env->me_map)) {
+        mdbx_rdt_unlock(env);
+        return MDBX_EPERM;
+      }
+#endif /* Windows */
       rc = MDBX_SUCCESS;
 
       if (unlikely(env->me_live_reader != env->me_pid)) {
@@ -3237,6 +3271,16 @@ static int mdbx_txn_renew0(MDBX_txn *txn, unsigned flags) {
     rc = mdbx_txn_lock(env, F_ISSET(flags, MDBX_TRYTXN));
     if (unlikely(rc))
       return rc;
+    if (unlikely(env->me_flags & MDBX_FATAL_ERROR)) {
+      mdbx_txn_unlock(env);
+      return MDBX_PANIC;
+    }
+#if defined(_WIN32) || defined(_WIN64)
+    if (unlikely(!env->me_map)) {
+      mdbx_txn_unlock(env);
+      return MDBX_EPERM;
+    }
+#endif /* Windows */
 
     mdbx_jitter4testing(false);
     MDBX_meta *meta = mdbx_meta_head(env);
@@ -3296,8 +3340,11 @@ static int mdbx_txn_renew0(MDBX_txn *txn, unsigned flags) {
         goto bailout;
       }
       rc = mdbx_mapresize(env, txn->mt_end_pgno, upper_pgno);
-      if (rc != MDBX_SUCCESS)
+      if (rc != MDBX_SUCCESS) {
+        if (rc == MDBX_RESULT_TRUE)
+          rc = MDBX_MAP_RESIZED;
         goto bailout;
+      }
     }
     txn->mt_owner = mdbx_thread_self();
     return MDBX_SUCCESS;
@@ -3345,6 +3392,7 @@ int mdbx_txn_begin(MDBX_env *env, MDBX_txn *parent, unsigned flags,
   if (unlikely(!env || !ret))
     return MDBX_EINVAL;
 
+  *ret = NULL;
   if (unlikely(env->me_signature != MDBX_ME_SIGNATURE))
     return MDBX_EBADSIGN;
 
@@ -3354,8 +3402,12 @@ int mdbx_txn_begin(MDBX_env *env, MDBX_txn *parent, unsigned flags,
   if (unlikely(env->me_flags & MDBX_FATAL_ERROR))
     return MDBX_PANIC;
 
+#if !defined(_WIN32) && !defined(_WIN64)
+  /* Don't check env->me_map until lock to avoid race with re-mapping for
+   * shrinking */
   if (unlikely(!env->me_map))
     return MDBX_EPERM;
+#endif /* Windows */
 
   flags &= MDBX_TXN_BEGIN_FLAGS;
   flags |= env->me_flags & MDBX_WRITEMAP;
@@ -3366,16 +3418,21 @@ int mdbx_txn_begin(MDBX_env *env, MDBX_txn *parent, unsigned flags,
 
   if (parent) {
     if (unlikely(parent->mt_signature != MDBX_MT_SIGNATURE))
-      return MDBX_EINVAL;
+      return MDBX_EBADSIGN;
 
     if (unlikely(parent->mt_owner != mdbx_thread_self()))
       return MDBX_THREAD_MISMATCH;
 
+#if defined(_WIN32) || defined(_WIN64)
+    if (unlikely(!env->me_map))
+      return MDBX_EPERM;
+#endif /* Windows */
+
     /* Nested transactions: Max 1 child, write txns only, no writemap */
     flags |= parent->mt_flags;
-    if (unlikely(flags & (MDBX_RDONLY | MDBX_WRITEMAP | MDBX_TXN_BLOCKED))) {
+    if (unlikely(flags & (MDBX_RDONLY | MDBX_WRITEMAP | MDBX_TXN_BLOCKED)))
       return (parent->mt_flags & MDBX_TXN_RDONLY) ? MDBX_EINVAL : MDBX_BAD_TXN;
-    }
+
     /* Child txns save MDBX_pgstate and use own copy of cursors */
     size = env->me_maxdbs * (sizeof(MDBX_db) + sizeof(MDBX_cursor *) + 1);
     size += tsize = sizeof(MDBX_ntxn);
@@ -3392,7 +3449,7 @@ int mdbx_txn_begin(MDBX_env *env, MDBX_txn *parent, unsigned flags,
       return MDBX_BUSY;
     goto renew;
   }
-  if (unlikely((txn = malloc(size)) == NULL)) {
+  if (unlikely((txn = mdbx_malloc(size)) == NULL)) {
     mdbx_debug("calloc: %s", "failed");
     return MDBX_ENOMEM;
   }
@@ -3407,11 +3464,12 @@ int mdbx_txn_begin(MDBX_env *env, MDBX_txn *parent, unsigned flags,
     unsigned i;
     txn->mt_cursors = (MDBX_cursor **)(txn->mt_dbs + env->me_maxdbs);
     txn->mt_dbiseqs = parent->mt_dbiseqs;
-    txn->mt_rw_dirtylist = malloc(sizeof(MDBX_DP) * (MDBX_DPL_TXNFULL + 1));
+    txn->mt_rw_dirtylist =
+        mdbx_malloc(sizeof(MDBX_DP) * (MDBX_DPL_TXNFULL + 1));
     if (!txn->mt_rw_dirtylist ||
         !(txn->mt_befree_pages = mdbx_pnl_alloc(MDBX_PNL_INITIAL))) {
-      free(txn->mt_rw_dirtylist);
-      free(txn);
+      mdbx_free(txn->mt_rw_dirtylist);
+      mdbx_free(txn);
       return MDBX_ENOMEM;
     }
     txn->mt_txnid = parent->mt_txnid;
@@ -3452,10 +3510,12 @@ int mdbx_txn_begin(MDBX_env *env, MDBX_txn *parent, unsigned flags,
     rc = mdbx_txn_renew0(txn, flags);
   }
 
-  if (unlikely(rc)) {
+  if (unlikely(rc != MDBX_SUCCESS)) {
     if (txn != env->me_txn0)
-      free(txn);
+      mdbx_free(txn);
   } else {
+    mdbx_assert(env,
+                (txn->mt_flags & ~(MDBX_TXN_RDONLY | MDBX_TXN_WRITEMAP)) == 0);
     txn->mt_signature = MDBX_MT_SIGNATURE;
     *ret = txn;
     mdbx_debug("begin txn %" PRIaTXN "%c %p on env %p, root page %" PRIaPGNO
@@ -3516,7 +3576,7 @@ static void mdbx_dbis_update(MDBX_txn *txn, int keep) {
           mdbx_assert(env, env->me_dbflags[i] == 0);
           env->me_dbiseqs[i]++;
           env->me_dbxs[i].md_name.iov_base = NULL;
-          free(ptr);
+          mdbx_free(ptr);
         }
       }
     }
@@ -3601,7 +3661,7 @@ static int mdbx_txn_end(MDBX_txn *txn, unsigned mode) {
       env->me_pgstate = ((MDBX_ntxn *)txn)->mnt_pgstate;
       mdbx_pnl_free(txn->mt_befree_pages);
       mdbx_pnl_free(txn->mt_spill_pages);
-      free(txn->mt_rw_dirtylist);
+      mdbx_free(txn->mt_rw_dirtylist);
     }
 
     mdbx_pnl_free(pghead);
@@ -3610,7 +3670,7 @@ static int mdbx_txn_end(MDBX_txn *txn, unsigned mode) {
   mdbx_assert(env, txn == env->me_txn0 || txn->mt_owner == 0);
   if ((mode & MDBX_END_FREE) != 0 && txn != env->me_txn0) {
     txn->mt_signature = 0;
-    free(txn);
+    mdbx_free(txn);
   }
 
   return MDBX_SUCCESS;
@@ -3646,7 +3706,7 @@ int mdbx_txn_abort(MDBX_txn *txn) {
   if (unlikely(txn->mt_signature != MDBX_MT_SIGNATURE))
     return MDBX_EBADSIGN;
 
-  if (unlikely(txn->mt_owner && txn->mt_owner != mdbx_thread_self()))
+  if (unlikely(txn->mt_owner != mdbx_thread_self()))
     return MDBX_THREAD_MISMATCH;
 
   if (F_ISSET(txn->mt_flags, MDBX_TXN_RDONLY))
@@ -4498,7 +4558,7 @@ static int mdbx_page_flush(MDBX_txn *txn, pgno_t keep) {
         /* Write previous page(s) */
         rc = mdbx_pwritev(env->me_fd, iov, n, wpos, wsize);
         if (unlikely(rc != MDBX_SUCCESS)) {
-          mdbx_debug("Write error: %s", strerror(rc));
+          mdbx_debug("Write error: %s", mdbx_strerror(rc));
           return rc;
         }
         n = 0;
@@ -4691,7 +4751,7 @@ int mdbx_txn_commit(MDBX_txn *txn) {
         pn >>= 1;
         y = mdbx_dpl_search(dst, pn);
         if (y <= dst->length && dst[y].pgno == pn) {
-          free(dst[y].ptr);
+          mdbx_free(dst[y].ptr);
           while (y < dst->length) {
             dst[y] = dst[y + 1];
             y++;
@@ -4726,11 +4786,11 @@ int mdbx_txn_commit(MDBX_txn *txn) {
       while (yp < dst[x].pgno)
         dst[i--] = dst[x--];
       if (yp == dst[x].pgno)
-        free(dst[x--].ptr);
+        mdbx_free(dst[x--].ptr);
     }
     mdbx_tassert(txn, i == x);
     dst->length = len;
-    free(txn->mt_rw_dirtylist);
+    mdbx_free(txn->mt_rw_dirtylist);
     parent->mt_dirtyroom = txn->mt_dirtyroom;
     if (txn->mt_spill_pages) {
       if (parent->mt_spill_pages) {
@@ -4754,7 +4814,7 @@ int mdbx_txn_commit(MDBX_txn *txn) {
     parent->mt_child = NULL;
     mdbx_pnl_free(((MDBX_ntxn *)txn)->mnt_pgstate.mf_reclaimed_pglist);
     txn->mt_signature = 0;
-    free(txn);
+    mdbx_free(txn);
     return rc;
   }
 
@@ -4836,8 +4896,10 @@ int mdbx_txn_commit(MDBX_txn *txn) {
     rc = mdbx_sync_locked(
         env, env->me_flags | txn->mt_flags | MDBX_SHRINK_ALLOWED, &meta);
   }
-  if (unlikely(rc != MDBX_SUCCESS))
+  if (unlikely(rc != MDBX_SUCCESS)) {
+    env->me_flags |= MDBX_FATAL_ERROR;
     goto fail;
+  }
 
   if (likely(env->me_lck))
     env->me_lck->mti_readers_refresh_flag = false;
@@ -4905,7 +4967,8 @@ static int __cold mdbx_read_header(MDBX_env *env, MDBX_meta *meta,
       mdbx_info("meta[%u] was updated, re-read it", meta_number);
     }
 
-    if (page.mp_meta.mm_magic_and_version != MDBX_DATA_MAGIC && page.mp_meta.mm_magic_and_version != MDBX_DATA_DEBUG) {
+    if (page.mp_meta.mm_magic_and_version != MDBX_DATA_MAGIC &&
+        page.mp_meta.mm_magic_and_version != MDBX_DATA_MAGIC_DEVEL) {
       mdbx_error("meta[%u] has invalid magic/version %" PRIx64, meta_number,
                  page.mp_meta.mm_magic_and_version);
       return ((page.mp_meta.mm_magic_and_version >> 8) != MDBX_MAGIC)
@@ -5466,7 +5529,7 @@ static void __cold mdbx_setup_pagesize(MDBX_env *env, const size_t pagesize) {
 }
 
 int __cold mdbx_env_create(MDBX_env **penv) {
-  MDBX_env *env = calloc(1, sizeof(MDBX_env));
+  MDBX_env *env = mdbx_calloc(1, sizeof(MDBX_env));
   if (!env)
     return MDBX_ENOMEM;
 
@@ -5513,7 +5576,7 @@ int __cold mdbx_env_create(MDBX_env **penv) {
   return MDBX_SUCCESS;
 
 bailout:
-  free(env);
+  mdbx_free(env);
   *penv = nullptr;
   return rc;
 }
@@ -5867,13 +5930,13 @@ static int __cold mdbx_setup_dxb(MDBX_env *env, int lck_rc) {
         return err;
     }
 
-    void *buffer = calloc(NUM_METAS, env->me_psize);
+    void *buffer = mdbx_calloc(NUM_METAS, env->me_psize);
     if (!buffer)
       return MDBX_ENOMEM;
 
     meta = mdbx_init_metas(env, buffer)->mp_meta;
     err = mdbx_pwrite(env->me_fd, buffer, env->me_psize * NUM_METAS, 0);
-    free(buffer);
+    mdbx_free(buffer);
     if (unlikely(err != MDBX_SUCCESS))
       return err;
 
@@ -6168,9 +6231,7 @@ static int __cold mdbx_setup_lck(MDBX_env *env, char *lck_pathname,
   mdbx_assert(env, env->me_fd != INVALID_HANDLE_VALUE);
   mdbx_assert(env, env->me_lfd == INVALID_HANDLE_VALUE);
 
-  const int open_flags =
-      (env->me_flags & MDBX_EXCLUSIVE) ? O_RDWR : O_RDWR | O_CREAT;
-  int err = mdbx_openfile(lck_pathname, open_flags, mode, &env->me_lfd,
+  int err = mdbx_openfile(lck_pathname, O_RDWR | O_CREAT, mode, &env->me_lfd,
                           (env->me_flags & MDBX_EXCLUSIVE) ? true : false);
   if (err != MDBX_SUCCESS) {
     if (!(err == MDBX_ENOFILE && (env->me_flags & MDBX_EXCLUSIVE)) &&
@@ -6277,7 +6338,8 @@ static int __cold mdbx_setup_lck(MDBX_env *env, char *lck_pathname,
     env->me_lck->mti_magic_and_version = MDBX_LOCK_MAGIC;
     env->me_lck->mti_os_and_format = MDBX_LOCK_FORMAT;
   } else {
-    if (env->me_lck->mti_magic_and_version != MDBX_LOCK_MAGIC && env->me_lck->mti_magic_and_version != MDBX_LOCK_DEBUG) {
+    if (env->me_lck->mti_magic_and_version != MDBX_LOCK_MAGIC &&
+        env->me_lck->mti_magic_and_version != MDBX_LOCK_MAGIC_DEVEL) {
       mdbx_error("lock region has invalid magic/version");
       return ((env->me_lck->mti_magic_and_version >> 8) != MDBX_MAGIC)
                  ? MDBX_INVALID
@@ -6333,7 +6395,7 @@ int __cold mdbx_env_open(MDBX_env *env, const char *path, unsigned flags,
   } else {
     len_full = len + sizeof(MDBX_LOCKNAME) + len + sizeof(MDBX_DATANAME);
   }
-  char *lck_pathname = malloc(len_full);
+  char *lck_pathname = mdbx_malloc(len_full);
   if (!lck_pathname)
     return MDBX_ENOMEM;
 
@@ -6357,7 +6419,8 @@ int __cold mdbx_env_open(MDBX_env *env, const char *path, unsigned flags,
                MDBX_COALESCE | MDBX_LIFORECLAIM | MDBX_NOMEMINIT);
   } else {
     if (!((env->me_free_pgs = mdbx_pnl_alloc(MDBX_PNL_INITIAL)) &&
-          (env->me_dirtylist = calloc(MDBX_DPL_TXNFULL + 1, sizeof(MDBX_DP)))))
+          (env->me_dirtylist =
+               mdbx_calloc(MDBX_DPL_TXNFULL + 1, sizeof(MDBX_DP)))))
       rc = MDBX_ENOMEM;
   }
 
@@ -6367,9 +6430,9 @@ int __cold mdbx_env_open(MDBX_env *env, const char *path, unsigned flags,
     goto bailout;
 
   env->me_path = mdbx_strdup(path);
-  env->me_dbxs = calloc(env->me_maxdbs, sizeof(MDBX_dbx));
-  env->me_dbflags = calloc(env->me_maxdbs, sizeof(env->me_dbflags[0]));
-  env->me_dbiseqs = calloc(env->me_maxdbs, sizeof(env->me_dbiseqs[0]));
+  env->me_dbxs = mdbx_calloc(env->me_maxdbs, sizeof(MDBX_dbx));
+  env->me_dbflags = mdbx_calloc(env->me_maxdbs, sizeof(env->me_dbflags[0]));
+  env->me_dbiseqs = mdbx_calloc(env->me_maxdbs, sizeof(env->me_dbiseqs[0]));
   if (!(env->me_dbxs && env->me_path && env->me_dbflags && env->me_dbiseqs)) {
     rc = MDBX_ENOMEM;
     goto bailout;
@@ -6448,7 +6511,8 @@ int __cold mdbx_env_open(MDBX_env *env, const char *path, unsigned flags,
         size =
             tsize + env->me_maxdbs * (sizeof(MDBX_db) + sizeof(MDBX_cursor *) +
                                       sizeof(unsigned) + 1);
-    if ((env->me_pbuf = calloc(1, env->me_psize)) && (txn = calloc(1, size))) {
+    if ((env->me_pbuf = mdbx_calloc(2, env->me_psize)) &&
+        (txn = mdbx_calloc(1, size))) {
       txn->mt_dbs = (MDBX_db *)((char *)txn + tsize);
       txn->mt_cursors = (MDBX_cursor **)(txn->mt_dbs + env->me_maxdbs);
       txn->mt_dbiseqs = (unsigned *)(txn->mt_cursors + env->me_maxdbs);
@@ -6486,7 +6550,7 @@ bailout:
     mdbx_env_close0(env);
     env->me_flags = saved_me_flags | MDBX_FATAL_ERROR;
   }
-  free(lck_pathname);
+  mdbx_free(lck_pathname);
   return rc;
 }
 
@@ -6499,18 +6563,18 @@ static void __cold mdbx_env_close0(MDBX_env *env) {
   /* Doing this here since me_dbxs may not exist during mdbx_env_close */
   if (env->me_dbxs) {
     for (unsigned i = env->me_maxdbs; --i >= CORE_DBS;)
-      free(env->me_dbxs[i].md_name.iov_base);
-    free(env->me_dbxs);
+      mdbx_free(env->me_dbxs[i].md_name.iov_base);
+    mdbx_free(env->me_dbxs);
   }
 
-  free(env->me_pbuf);
-  free(env->me_dbiseqs);
-  free(env->me_dbflags);
-  free(env->me_path);
-  free(env->me_dirtylist);
+  mdbx_free(env->me_pbuf);
+  mdbx_free(env->me_dbiseqs);
+  mdbx_free(env->me_dbflags);
+  mdbx_free(env->me_path);
+  mdbx_free(env->me_dirtylist);
   if (env->me_txn0) {
     mdbx_txl_free(env->me_txn0->mt_lifo_reclaimed);
-    free(env->me_txn0);
+    mdbx_free(env->me_txn0);
   }
   mdbx_pnl_free(env->me_free_pgs);
 
@@ -6578,7 +6642,7 @@ int __cold mdbx_env_close_ex(MDBX_env *env, int dont_sync) {
     ASAN_UNPOISON_MEMORY_REGION(&dp->mp_next, sizeof(dp->mp_next));
     VALGRIND_MAKE_MEM_DEFINED(&dp->mp_next, sizeof(dp->mp_next));
     env->me_dpages = dp->mp_next;
-    free(dp);
+    mdbx_free(dp);
   }
 
   mdbx_env_close0(env);
@@ -6595,7 +6659,7 @@ int __cold mdbx_env_close_ex(MDBX_env *env, int dont_sync) {
 
   env->me_pid = 0;
   env->me_signature = 0;
-  free(env);
+  mdbx_free(env);
 
   return rc;
 }
@@ -6927,13 +6991,20 @@ mapped:
   p = pgno2page(env, pgno);
 
 done:
-  if (unlikely(p->mp_pgno != pgno))
+  if (unlikely(p->mp_pgno != pgno)) {
+    mdbx_error("mismatch pgno %" PRIaPGNO " (actual) != %" PRIaPGNO
+               " (expected)",
+               p->mp_pgno, pgno);
     return MDBX_CORRUPTED;
+  }
 
   if (unlikely(p->mp_upper < p->mp_lower ||
                PAGEHDRSZ + p->mp_upper > env->me_psize) &&
-      !IS_OVERFLOW(p))
+      !IS_OVERFLOW(p)) {
+    mdbx_error("invalid page lower(%u)/upper(%u), pg-limit %u", p->mp_lower,
+               p->mp_upper, env->me_psize - PAGEHDRSZ);
     return MDBX_CORRUPTED;
+  }
   /* TODO: more checks here, including p->mp_validator */
 
   *ret = p;
@@ -9393,10 +9464,10 @@ int mdbx_cursor_open(MDBX_txn *txn, MDBX_dbi dbi, MDBX_cursor **ret) {
                           : sizeof(MDBX_cursor);
 
   MDBX_cursor *mc;
-  if (likely((mc = malloc(size)) != NULL)) {
+  if (likely((mc = mdbx_malloc(size)) != NULL)) {
     int rc = mdbx_cursor_init(mc, txn, dbi);
     if (unlikely(rc != MDBX_SUCCESS)) {
-      free(mc);
+      mdbx_free(mc);
       return rc;
     }
     if (txn->mt_cursors) {
@@ -9508,7 +9579,7 @@ void mdbx_cursor_close(MDBX_cursor *mc) {
           *prev = mc->mc_next;
       }
       mc->mc_signature = 0;
-      free(mc);
+      mdbx_free(mc);
     } else {
       /* cursor closed before nested txn ends */
       mdbx_cassert(mc, mc->mc_signature == MDBX_MC_SIGNATURE);
@@ -11248,7 +11319,7 @@ static int __cold mdbx_env_cwalk(mdbx_copy *my, pgno_t *pg, int flags) {
     return rc;
 
   /* Make cursor pages writable */
-  buf = ptr = malloc(pgno2bytes(my->mc_env, mc.mc_snum));
+  buf = ptr = mdbx_malloc(pgno2bytes(my->mc_env, mc.mc_snum));
   if (buf == NULL)
     return MDBX_ENOMEM;
 
@@ -11373,7 +11444,7 @@ static int __cold mdbx_env_cwalk(mdbx_copy *my, pgno_t *pg, int flags) {
     }
   }
 done:
-  free(buf);
+  mdbx_free(buf);
   return rc;
 }
 
@@ -11545,7 +11616,7 @@ int __cold mdbx_env_copy(MDBX_env *env, const char *dest_path, unsigned flags) {
   } else {
     size_t len = strlen(dest_path);
     len += sizeof(MDBX_DATANAME);
-    dxb_pathname = malloc(len);
+    dxb_pathname = mdbx_malloc(len);
     if (!dxb_pathname)
       return MDBX_ENOMEM;
     sprintf(dxb_pathname, "%s" MDBX_DATANAME, dest_path);
@@ -11578,7 +11649,7 @@ int __cold mdbx_env_copy(MDBX_env *env, const char *dest_path, unsigned flags) {
   }
 
   if (dxb_pathname != dest_path)
-    free(dxb_pathname);
+    mdbx_free(dxb_pathname);
 
   return rc;
 }
@@ -11897,7 +11968,7 @@ int mdbx_dbi_open_ex(MDBX_txn *txn, const char *table_name, unsigned user_flags,
 
   int err = mdbx_fastmutex_acquire(&env->me_dbi_lock);
   if (unlikely(err != MDBX_SUCCESS)) {
-    free(namedup);
+    mdbx_free(namedup);
     return err;
   }
 
@@ -11961,7 +12032,7 @@ int mdbx_dbi_open_ex(MDBX_txn *txn, const char *table_name, unsigned user_flags,
   if (unlikely(rc != MDBX_SUCCESS)) {
     mdbx_tassert(txn, (dbflag & DB_CREAT) == 0);
   bailout:
-    free(namedup);
+    mdbx_free(namedup);
   } else {
     txn->mt_dbiseqs[slot] = (env->me_dbiseqs[slot] += 1);
     txn->mt_dbflags[slot] = (uint8_t)dbflag;
@@ -12032,7 +12103,7 @@ static int mdbx_dbi_close_locked(MDBX_env *env, MDBX_dbi dbi) {
   mdbx_compiler_barrier();
   env->me_dbiseqs[dbi]++;
   env->me_dbxs[dbi].md_name.iov_base = NULL;
-  free(ptr);
+  mdbx_free(ptr);
   return MDBX_SUCCESS;
 }
 
@@ -12391,7 +12462,14 @@ int __cold mdbx_reader_check0(MDBX_env *env, int rdt_locked, int *dead) {
   }
 
   const unsigned snap_nreaders = lck->mti_numreaders;
-  mdbx_pid_t *pids = alloca((snap_nreaders + 1) * sizeof(mdbx_pid_t));
+  mdbx_pid_t pidsbuf_onstask[142];
+  mdbx_pid_t *const pids =
+      (snap_nreaders < ARRAY_LENGTH(pidsbuf_onstask))
+          ? pidsbuf_onstask
+          : mdbx_malloc((snap_nreaders + 1) * sizeof(mdbx_pid_t));
+  if (unlikely(!pids))
+    return MDBX_ENOMEM;
+
   pids[0] = 0;
 
   int rc = MDBX_SUCCESS, count = 0;
@@ -12457,6 +12535,9 @@ int __cold mdbx_reader_check0(MDBX_env *env, int rdt_locked, int *dead) {
   if (rdt_locked < 0)
     mdbx_rdt_unlock(env);
 
+  if (pids != pidsbuf_onstask)
+    mdbx_free(pids);
+
   if (dead)
     *dead = count;
   return rc;
@@ -12747,9 +12828,20 @@ static int __cold mdbx_env_walk(mdbx_walk_ctx_t *ctx, const char *dbi,
 
       MDBX_db db;
       memcpy(&db, NODEDATA(node), sizeof(db));
-      char *name = memcpy(alloca(namelen + 1), NODEKEY(node), namelen);
-      name[namelen] = 0;
-      rc = mdbx_env_walk(ctx, name, db.md_root, deep + 1);
+
+      char namebuf_onstask[142];
+      char *const name = (namelen < sizeof(namebuf_onstask))
+                             ? namebuf_onstask
+                             : mdbx_malloc(namelen + 1);
+      if (name) {
+        memcpy(name, NODEKEY(node), namelen);
+        name[namelen] = 0;
+        rc = mdbx_env_walk(ctx, name, db.md_root, deep + 1);
+        if (name != namebuf_onstask)
+          mdbx_free(name);
+      } else {
+        rc = MDBX_ENOMEM;
+      }
     } break;
 
     case F_SUBDATA | F_DUPDATA /* dupsorted sub-tree */: {
@@ -13276,6 +13368,14 @@ int mdbx_dbi_sequence(MDBX_txn *txn, MDBX_dbi dbi, uint64_t *result,
   if (unlikely(TXN_DBI_CHANGED(txn, dbi)))
     return MDBX_BAD_DBI;
 
+  if (unlikely(txn->mt_dbflags[dbi] & DB_STALE)) {
+    MDBX_cursor_couple cx;
+    /* Stale, must read the DB's root. cursor_init does it for us. */
+    int rc = mdbx_cursor_init(&cx.outer, txn, dbi);
+    if (unlikely(rc != MDBX_SUCCESS))
+      return rc;
+  }
+
   MDBX_db *dbs = &txn->mt_dbs[dbi];
   if (likely(result))
     *result = dbs->md_seq;
diff --git a/libs/libmdbx/src/src/osal.c b/libs/libmdbx/src/src/osal.c
index 738a179465..b39eea4be8 100644
--- a/libs/libmdbx/src/src/osal.c
+++ b/libs/libmdbx/src/src/osal.c
@@ -53,6 +53,9 @@ static int ntstatus2errcode(NTSTATUS status) {
  * declare them here. Using these APIs also means we must link to
  * ntdll.dll, which is not linked by default in user code. */
 #pragma comment(lib, "ntdll.lib")
+#ifdef MDBX_AVOID_CRT
+#pragma comment(lib, "mdbx_ntdll_extra.lib")
+#endif
 
 extern NTSTATUS NTAPI NtCreateSection(
     OUT PHANDLE SectionHandle, IN ACCESS_MASK DesiredAccess,
@@ -137,6 +140,15 @@ typedef struct _FILE_PROVIDER_EXTERNAL_INFO_V1 {
 #define STATUS_INVALID_DEVICE_REQUEST ((NTSTATUS)0xC0000010L)
 #endif
 
+#ifndef FILE_DEVICE_FILE_SYSTEM
+#define FILE_DEVICE_FILE_SYSTEM 0x00000009
+#endif
+
+#ifndef FSCTL_GET_EXTERNAL_BACKING
+#define FSCTL_GET_EXTERNAL_BACKING                                             \
+  CTL_CODE(FILE_DEVICE_FILE_SYSTEM, 196, METHOD_BUFFERED, FILE_ANY_ACCESS)
+#endif
+
 #endif /* _WIN32 || _WIN64 */
 
 /*----------------------------------------------------------------------------*/
@@ -145,13 +157,8 @@ typedef struct _FILE_PROVIDER_EXTERNAL_INFO_V1 {
 /* Prototype should match libc runtime. ISO POSIX (2003) & LSB 3.1 */
 __nothrow __noreturn void __assert_fail(const char *assertion, const char *file,
                                         unsigned line, const char *function);
-#else
-__extern_C __declspec(dllimport) void __cdecl _assert(char const *message,
-                                                      char const *filename,
-                                                      unsigned line);
 #endif /* _MSC_VER */
 
-#ifndef mdbx_assert_fail
 void __cold mdbx_assert_fail(const MDBX_env *env, const char *msg,
                              const char *func, int line) {
 #if MDBX_DEBUG
@@ -165,49 +172,57 @@ void __cold mdbx_assert_fail(const MDBX_env *env, const char *msg,
 
   if (mdbx_debug_logger)
     mdbx_debug_log(MDBX_DBG_ASSERT, func, line, "assert: %s\n", msg);
-#ifndef _MSC_VER
-  __assert_fail(msg, "mdbx", line, func);
+  else {
+#if defined(_WIN32) || defined(_WIN64)
+    char *message = nullptr;
+    const int num = mdbx_asprintf(&message, "\r\nMDBX-ASSERTION: %s, %s:%u",
+                                  msg, func ? func : "unknown", line);
+    if (num < 1 || !message)
+      message = "<troubles with assertion-message preparation>";
+    OutputDebugStringA(message);
+    if (IsDebuggerPresent())
+      DebugBreak();
 #else
-  _assert(msg, func, line);
-#endif /* _MSC_VER */
+    __assert_fail(msg, "mdbx", line, func);
+#endif
+  }
+
+#if defined(_WIN32) || defined(_WIN64)
+  FatalExit(ERROR_UNHANDLED_ERROR);
+#else
+  abort();
+#endif
 }
-#endif /* mdbx_assert_fail */
 
 __cold void mdbx_panic(const char *fmt, ...) {
   va_list ap;
   va_start(ap, fmt);
-#ifdef _MSC_VER
-  if (IsDebuggerPresent()) {
-    OutputDebugStringA("\r\n" FIXME "\r\n");
-    FatalExit(ERROR_UNHANDLED_ERROR);
-  }
-#elif _XOPEN_SOURCE >= 700 || _POSIX_C_SOURCE >= 200809L ||                    \
-    (__GLIBC_PREREQ(1, 0) && !__GLIBC_PREREQ(2, 10) && defined(_GNU_SOURCE))
-  vdprintf(STDERR_FILENO, fmt, ap);
-#else
-#error FIXME
-#endif
+
+  char *message = nullptr;
+  const int num = mdbx_vasprintf(&message, fmt, ap);
   va_end(ap);
+  if (num < 1 || !message)
+    message = "<troubles with panic-message preparation>";
+
+#if defined(_WIN32) || defined(_WIN64)
+  OutputDebugStringA("\r\nMDBX-PANIC: ");
+  OutputDebugStringA(message);
+  if (IsDebuggerPresent())
+    DebugBreak();
+  FatalExit(ERROR_UNHANDLED_ERROR);
+#else
+  __assert_fail(message, "mdbx", 0, "panic");
   abort();
+#endif
 }
 
 /*----------------------------------------------------------------------------*/
 
-#ifndef mdbx_asprintf
-int mdbx_asprintf(char **strp, const char *fmt, ...) {
-  va_list ap, ones;
-
-  va_start(ap, fmt);
+#ifndef mdbx_vasprintf
+int mdbx_vasprintf(char **strp, const char *fmt, va_list ap) {
+  va_list ones;
   va_copy(ones, ap);
-#ifdef _MSC_VER
-  int needed = _vscprintf(fmt, ap);
-#elif defined(vsnprintf) || defined(_BSD_SOURCE) || _XOPEN_SOURCE >= 500 ||    \
-    defined(_ISOC99_SOURCE) || _POSIX_C_SOURCE >= 200112L
   int needed = vsnprintf(nullptr, 0, fmt, ap);
-#else
-#error FIXME
-#endif
-  va_end(ap);
 
   if (unlikely(needed < 0 || needed >= INT_MAX)) {
     *strp = nullptr;
@@ -215,34 +230,44 @@ int mdbx_asprintf(char **strp, const char *fmt, ...) {
     return needed;
   }
 
-  *strp = malloc(needed + 1);
+  *strp = mdbx_malloc(needed + 1);
   if (unlikely(*strp == nullptr)) {
     va_end(ones);
+#if defined(_WIN32) || defined(_WIN64)
     SetLastError(MDBX_ENOMEM);
+#else
+    errno = MDBX_ENOMEM;
+#endif
     return -1;
   }
 
-#if defined(vsnprintf) || defined(_BSD_SOURCE) || _XOPEN_SOURCE >= 500 ||      \
-    defined(_ISOC99_SOURCE) || _POSIX_C_SOURCE >= 200112L
   int actual = vsnprintf(*strp, needed + 1, fmt, ones);
-#else
-#error FIXME
-#endif
   va_end(ones);
 
   assert(actual == needed);
   if (unlikely(actual < 0)) {
-    free(*strp);
+    mdbx_free(*strp);
     *strp = nullptr;
   }
   return actual;
 }
+#endif /* mdbx_vasprintf */
+
+#ifndef mdbx_asprintf
+int mdbx_asprintf(char **strp, const char *fmt, ...) {
+  va_list ap;
+  va_start(ap, fmt);
+  int rc = mdbx_vasprintf(strp, fmt, ap);
+  va_end(ap);
+  return rc;
+}
 #endif /* mdbx_asprintf */
 
 #ifndef mdbx_memalign_alloc
 int mdbx_memalign_alloc(size_t alignment, size_t bytes, void **result) {
-#if _MSC_VER
-  *result = _aligned_malloc(bytes, alignment);
+#if defined(_WIN32) || defined(_WIN64)
+  (void)alignment;
+  *result = VirtualAlloc(NULL, bytes, MEM_COMMIT | MEM_RESERVE, PAGE_READWRITE);
   return *result ? MDBX_SUCCESS : MDBX_ENOMEM /* ERROR_OUTOFMEMORY */;
 #elif __GLIBC_PREREQ(2, 16) || __STDC_VERSION__ >= 201112L
   *result = memalign(alignment, bytes);
@@ -258,14 +283,26 @@ int mdbx_memalign_alloc(size_t alignment, size_t bytes, void **result) {
 
 #ifndef mdbx_memalign_free
 void mdbx_memalign_free(void *ptr) {
-#if _MSC_VER
-  _aligned_free(ptr);
+#if defined(_WIN32) || defined(_WIN64)
+  VirtualFree(ptr, 0, MEM_RELEASE);
 #else
-  free(ptr);
+  mdbx_free(ptr);
 #endif
 }
 #endif /* mdbx_memalign_free */
 
+#ifndef mdbx_strdup
+char *mdbx_strdup(const char *str) {
+  if (!str)
+    return NULL;
+  size_t bytes = strlen(str) + 1;
+  char *dup = mdbx_malloc(bytes);
+  if (dup)
+    memcpy(dup, str, bytes);
+  return dup;
+}
+#endif /* mdbx_strdup */
+
 /*----------------------------------------------------------------------------*/
 
 int mdbx_condmutex_init(mdbx_condmutex_t *condmutex) {
@@ -797,33 +834,47 @@ int mdbx_check4nonlocal(mdbx_filehandle_t handle, int flags) {
   }
 
   if (mdbx_GetVolumeInformationByHandleW && mdbx_GetFinalPathNameByHandleW) {
-    WCHAR PathBuffer[INT16_MAX];
+    WCHAR *PathBuffer = mdbx_malloc(sizeof(WCHAR) * INT16_MAX);
+    if (!PathBuffer)
+      return MDBX_ENOMEM;
+
+    int rc = MDBX_SUCCESS;
     DWORD VolumeSerialNumber, FileSystemFlags;
     if (!mdbx_GetVolumeInformationByHandleW(handle, PathBuffer, INT16_MAX,
                                             &VolumeSerialNumber, NULL,
-                                            &FileSystemFlags, NULL, 0))
-      return GetLastError();
+                                            &FileSystemFlags, NULL, 0)) {
+      rc = GetLastError();
+      goto bailout;
+    }
 
     if ((flags & MDBX_RDONLY) == 0) {
-      if (FileSystemFlags & (FILE_SEQUENTIAL_WRITE_ONCE |
-                             FILE_READ_ONLY_VOLUME | FILE_VOLUME_IS_COMPRESSED))
-        return ERROR_REMOTE_STORAGE_MEDIA_ERROR;
+      if (FileSystemFlags &
+          (FILE_SEQUENTIAL_WRITE_ONCE | FILE_READ_ONLY_VOLUME |
+           FILE_VOLUME_IS_COMPRESSED)) {
+        rc = ERROR_REMOTE_STORAGE_MEDIA_ERROR;
+        goto bailout;
+      }
     }
 
     if (!mdbx_GetFinalPathNameByHandleW(handle, PathBuffer, INT16_MAX,
-                                        FILE_NAME_NORMALIZED | VOLUME_NAME_NT))
-      return GetLastError();
+                                        FILE_NAME_NORMALIZED |
+                                            VOLUME_NAME_NT)) {
+      rc = GetLastError();
+      goto bailout;
+    }
 
     if (_wcsnicmp(PathBuffer, L"\\Device\\Mup\\", 12) == 0) {
-      if (!(flags & MDBX_EXCLUSIVE))
-        return ERROR_REMOTE_STORAGE_MEDIA_ERROR;
+      if (!(flags & MDBX_EXCLUSIVE)) {
+        rc = ERROR_REMOTE_STORAGE_MEDIA_ERROR;
+        goto bailout;
+      }
     } else if (mdbx_GetFinalPathNameByHandleW(handle, PathBuffer, INT16_MAX,
                                               FILE_NAME_NORMALIZED |
                                                   VOLUME_NAME_DOS)) {
       UINT DriveType = GetDriveTypeW(PathBuffer);
       if (DriveType == DRIVE_NO_ROOT_DIR &&
-          wcsncmp(PathBuffer, L"\\\\?\\", 4) == 0 &&
-          wcsncmp(PathBuffer + 5, L":\\", 2) == 0) {
+          _wcsnicmp(PathBuffer, L"\\\\?\\", 4) == 0 &&
+          _wcsnicmp(PathBuffer + 5, L":\\", 2) == 0) {
         PathBuffer[7] = 0;
         DriveType = GetDriveTypeW(PathBuffer + 4);
       }
@@ -837,7 +888,7 @@ int mdbx_check4nonlocal(mdbx_filehandle_t handle, int flags) {
       case DRIVE_REMOTE:
       default:
         if (!(flags & MDBX_EXCLUSIVE))
-          return ERROR_REMOTE_STORAGE_MEDIA_ERROR;
+          rc = ERROR_REMOTE_STORAGE_MEDIA_ERROR;
       // fall through
       case DRIVE_REMOVABLE:
       case DRIVE_FIXED:
@@ -845,6 +896,9 @@ int mdbx_check4nonlocal(mdbx_filehandle_t handle, int flags) {
         break;
       }
     }
+  bailout:
+    mdbx_free(PathBuffer);
+    return rc;
   }
 #else
   (void)handle;
@@ -1019,11 +1073,11 @@ int mdbx_mresize(int flags, mdbx_mmap_t *map, size_t size, size_t limit) {
                                    &ReservedSize, MEM_RESERVE, PAGE_NOACCESS);
   if (!NT_SUCCESS(status)) {
     ReservedAddress = NULL;
-    if (status != /* STATUS_CONFLICTING_ADDRESSES */ 0xC0000018 ||
-        limit == map->length)
+    if (status != /* STATUS_CONFLICTING_ADDRESSES */ 0xC0000018)
       goto bailout_ntstatus /* no way to recovery */;
 
-    /* assume we can change base address if mapping size changed */
+    /* assume we can change base address if mapping size changed or prev address
+     * couldn't be used */
     map->address = NULL;
   }
 
@@ -1080,8 +1134,8 @@ retry_mapview:;
 
   if (!NT_SUCCESS(status)) {
     if (status == /* STATUS_CONFLICTING_ADDRESSES */ 0xC0000018 &&
-        map->address && limit != map->length) {
-      /* try remap at another base address, but only if the limit is changing */
+        map->address) {
+      /* try remap at another base address */
       map->address = NULL;
       goto retry_mapview;
     }
diff --git a/libs/libmdbx/src/src/osal.h b/libs/libmdbx/src/src/osal.h
index 065128103e..50416d960c 100644
--- a/libs/libmdbx/src/src/osal.h
+++ b/libs/libmdbx/src/src/osal.h
@@ -28,10 +28,16 @@
 #pragma warning(disable : 4577) /* 'noexcept' used with no exception handling  \
                                  * mode specified; termination on exception is \
                                  * not guaranteed. Specify /EHsc */
+#endif                          /* _MSC_VER (warnings) */
+
+#if defined(_WIN32) || defined(_WIN64)
 #if !defined(_CRT_SECURE_NO_WARNINGS)
 #define _CRT_SECURE_NO_WARNINGS
 #endif
-#endif /* _MSC_VER (warnings) */
+#if !defined(_NO_CRT_STDIO_INLINE) && defined(MDBX_BUILD_DLL)
+#define _NO_CRT_STDIO_INLINE
+#endif
+#endif /* Windows */
 
 /*----------------------------------------------------------------------------*/
 /* C99 includes */
@@ -84,7 +90,47 @@ typedef struct {
   HANDLE event;
 } mdbx_condmutex_t;
 typedef CRITICAL_SECTION mdbx_fastmutex_t;
+
+#ifdef MDBX_AVOID_CRT
+#ifndef mdbx_malloc
+static inline void *mdbx_malloc(size_t bytes) {
+  return LocalAlloc(LMEM_FIXED, bytes);
+}
+#endif /* mdbx_malloc */
+
+#ifndef mdbx_calloc
+static inline void *mdbx_calloc(size_t nelem, size_t size) {
+  return LocalAlloc(LMEM_FIXED | LMEM_ZEROINIT, nelem * size);
+}
+#endif /* mdbx_calloc */
+
+#ifndef mdbx_realloc
+static inline void *mdbx_realloc(void *ptr, size_t bytes) {
+  return LocalReAlloc(ptr, bytes, LMEM_MOVEABLE);
+}
+#endif /* mdbx_realloc */
+
+#ifndef mdbx_free
+#define mdbx_free LocalFree
+#endif /* mdbx_free */
 #else
+#define mdbx_malloc malloc
+#define mdbx_calloc calloc
+#define mdbx_realloc realloc
+#define mdbx_free free
+#define mdbx_strdup _strdup
+#endif /* MDBX_AVOID_CRT */
+
+#ifndef snprintf
+#define snprintf _snprintf /* ntdll */
+#endif
+
+#ifndef vsnprintf
+#define vsnprintf _vsnprintf /* ntdll */
+#endif
+
+#else /*----------------------------------------------------------------------*/
+
 #include <pthread.h>
 #include <signal.h>
 #include <sys/file.h>
@@ -103,6 +149,11 @@ typedef struct {
   pthread_cond_t cond;
 } mdbx_condmutex_t;
 typedef pthread_mutex_t mdbx_fastmutex_t;
+#define mdbx_malloc malloc
+#define mdbx_calloc calloc
+#define mdbx_realloc realloc
+#define mdbx_free free
+#define mdbx_strdup strdup
 #endif /* Platform */
 
 /* *INDENT-OFF* */
@@ -379,36 +430,14 @@ static __inline void mdbx_invalidate_cache(void *addr, size_t nbytes) {
 /*----------------------------------------------------------------------------*/
 /* libc compatibility stuff */
 
-#ifndef mdbx_assert_fail
-void mdbx_assert_fail(const MDBX_env *env, const char *msg, const char *func,
-                      int line);
-#endif /* mdbx_assert_fail */
-
 #if __GLIBC_PREREQ(2, 1)
 #define mdbx_asprintf asprintf
+#define mdbx_vasprintf vasprintf
 #else
-int mdbx_asprintf(char **strp, const char *fmt, ...);
-#endif
-
-#ifdef _MSC_VER
-
-#ifndef snprintf
-#define snprintf(buffer, buffer_size, format, ...)                             \
-  _snprintf_s(buffer, buffer_size, _TRUNCATE, format, __VA_ARGS__)
-#endif /* snprintf */
-
-#ifndef vsnprintf
-#define vsnprintf(buffer, buffer_size, format, args)                           \
-  _vsnprintf_s(buffer, buffer_size, _TRUNCATE, format, args)
-#endif /* vsnprintf */
-
-#ifdef _ASSERTE
-#undef assert
-#define assert _ASSERTE
+__printf_args(2, 3) int mdbx_asprintf(char **strp, const char *fmt, ...);
+int mdbx_vasprintf(char **strp, const char *fmt, va_list ap);
 #endif
 
-#endif /* _MSC_VER */
-
 /*----------------------------------------------------------------------------*/
 /* OS abstraction layer stuff */
 
@@ -428,13 +457,9 @@ static __inline size_t mdbx_syspagesize(void) {
 #endif
 }
 
-static __inline char *mdbx_strdup(const char *str) {
-#ifdef _MSC_VER
-  return _strdup(str);
-#else
-  return strdup(str);
+#ifndef mdbx_strdup
+LIBMDBX_API char *mdbx_strdup(const char *str);
 #endif
-}
 
 static __inline int mdbx_get_errno(void) {
 #if defined(_WIN32) || defined(_WIN64)
@@ -445,8 +470,12 @@ static __inline int mdbx_get_errno(void) {
   return rc;
 }
 
+#ifndef mdbx_memalign_alloc
 int mdbx_memalign_alloc(size_t alignment, size_t bytes, void **result);
+#endif
+#ifndef mdbx_memalign_free
 void mdbx_memalign_free(void *ptr);
+#endif
 
 int mdbx_condmutex_init(mdbx_condmutex_t *condmutex);
 int mdbx_condmutex_lock(mdbx_condmutex_t *condmutex);
@@ -564,14 +593,12 @@ int mdbx_rpid_set(MDBX_env *env);
 int mdbx_rpid_clear(MDBX_env *env);
 
 #if defined(_WIN32) || defined(_WIN64)
-typedef struct MDBX_srwlock {
-  union {
-    struct {
-      long volatile readerCount;
-      long volatile writerCount;
-    };
-    RTL_SRWLOCK native;
+typedef union MDBX_srwlock {
+  struct {
+    long volatile readerCount;
+    long volatile writerCount;
   };
+  RTL_SRWLOCK native;
 } MDBX_srwlock;
 
 typedef void(WINAPI *MDBX_srwlock_function)(MDBX_srwlock *);
@@ -652,6 +679,7 @@ static __inline uint32_t mdbx_atomic_add32(volatile uint32_t *p, uint32_t v) {
   return __sync_fetch_and_add(p, v);
 #else
 #ifdef _MSC_VER
+  STATIC_ASSERT(sizeof(volatile long) == sizeof(volatile uint32_t));
   return _InterlockedExchangeAdd((volatile long *)p, v);
 #endif
 #ifdef __APPLE__
@@ -692,7 +720,8 @@ static __inline bool mdbx_atomic_compare_and_swap32(volatile uint32_t *p,
   return __sync_bool_compare_and_swap(p, c, v);
 #else
 #ifdef _MSC_VER
-  return c == _InterlockedCompareExchange((volatile long*)p, v, c);
+  STATIC_ASSERT(sizeof(volatile long) == sizeof(volatile uint32_t));
+  return c == _InterlockedCompareExchange((volatile long *)p, v, c);
 #endif
 #ifdef __APPLE__
   return c == OSAtomicCompareAndSwap32Barrier(c, v, (volatile int32_t *)p);
diff --git a/libs/libmdbx/src/src/tools/mdbx_chk.c b/libs/libmdbx/src/src/tools/mdbx_chk.c
index ddaff0ab4b..6614bdb219 100644
--- a/libs/libmdbx/src/src/tools/mdbx_chk.c
+++ b/libs/libmdbx/src/src/tools/mdbx_chk.c
@@ -1,4 +1,4 @@
-/* mdbx_chk.c - memory-mapped database check tool */
+/* mdbx_chk.c - memory-mapped database check tool */
 
 /*
  * Copyright 2015-2018 Leonid Yuriev <leo@yuriev.ru>
@@ -141,12 +141,12 @@ static void
 static void pagemap_cleanup(void) {
   for (int i = CORE_DBS; ++i < MAX_DBI;) {
     if (walk.dbi[i].name) {
-      free((void *)walk.dbi[i].name);
+      mdbx_free((void *)walk.dbi[i].name);
       walk.dbi[i].name = NULL;
     }
   }
 
-  free(walk.pagemap);
+  mdbx_free(walk.pagemap);
   walk.pagemap = NULL;
 }
 
@@ -164,7 +164,7 @@ static walk_dbi_t *pagemap_lookup_dbi(const char *dbi_name, bool silent) {
       return NULL;
   }
 
-  dbi->name = strdup(dbi_name);
+  dbi->name = mdbx_strdup(dbi_name);
   if (verbose > 1 && !silent) {
     print(" - found '%s' area\n", dbi_name);
     fflush(NULL);
@@ -190,7 +190,7 @@ static void
         break;
 
     if (!p) {
-      p = calloc(1, sizeof(*p));
+      p = mdbx_calloc(1, sizeof(*p));
       p->caption = msg;
       p->pr_next = problems_list;
       problems_list = p;
@@ -233,7 +233,7 @@ static uint64_t problems_pop(struct problem *list) {
       count += problems_list->count;
       print("%s%s (%" PRIu64 ")", i ? ", " : "", problems_list->caption,
             problems_list->count);
-      free(problems_list);
+      mdbx_free(problems_list);
       problems_list = p;
     }
     print("\n");
@@ -497,13 +497,13 @@ static int handle_maindb(const uint64_t record_number, const MDBX_val *key,
       return handle_userdb(record_number, key, data);
   }
 
-  name = malloc(key->iov_len + 1);
+  name = mdbx_malloc(key->iov_len + 1);
   memcpy(name, key->iov_base, key->iov_len);
   name[key->iov_len] = '\0';
   userdb_count++;
 
   rc = process_db(~0u, name, handle_userdb, false);
-  free(name);
+  mdbx_free(name);
   if (rc != MDBX_INCOMPATIBLE)
     return rc;
 
@@ -1093,7 +1093,7 @@ int main(int argc, char *argv[]) {
 
     print("Traversal b-tree by txn#%" PRIaTXN "...\n", txn->mt_txnid);
     fflush(NULL);
-    walk.pagemap = calloc((size_t)lastpgno, sizeof(*walk.pagemap));
+    walk.pagemap = mdbx_calloc((size_t)lastpgno, sizeof(*walk.pagemap));
     if (!walk.pagemap) {
       rc = errno ? errno : MDBX_ENOMEM;
       error("calloc failed, error %d %s\n", rc, mdbx_strerror(rc));
diff --git a/libs/libmdbx/src/src/tools/mdbx_chk.vcxproj b/libs/libmdbx/src/src/tools/mdbx_chk.vcxproj
index d4cc420d36..e6c2686286 100644
--- a/libs/libmdbx/src/src/tools/mdbx_chk.vcxproj
+++ b/libs/libmdbx/src/src/tools/mdbx_chk.vcxproj
@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <Project DefaultTargets="Build" ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <ItemGroup Label="ProjectConfigurations">
     <ProjectConfiguration Include="Debug|Win32">
diff --git a/libs/libmdbx/src/src/tools/mdbx_copy.vcxproj b/libs/libmdbx/src/src/tools/mdbx_copy.vcxproj
index 6910060fcb..d47513c204 100644
--- a/libs/libmdbx/src/src/tools/mdbx_copy.vcxproj
+++ b/libs/libmdbx/src/src/tools/mdbx_copy.vcxproj
@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <Project DefaultTargets="Build" ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <ItemGroup Label="ProjectConfigurations">
     <ProjectConfiguration Include="Debug|Win32">
diff --git a/libs/libmdbx/src/src/tools/mdbx_dump.c b/libs/libmdbx/src/src/tools/mdbx_dump.c
index c854e0ad15..d16215622e 100644
--- a/libs/libmdbx/src/src/tools/mdbx_dump.c
+++ b/libs/libmdbx/src/src/tools/mdbx_dump.c
@@ -203,7 +203,8 @@ int main(int argc, char *argv[]) {
       break;
     case 'f':
       if (freopen(optarg, "w", stdout) == NULL) {
-        fprintf(stderr, "%s: %s: reopen: %s\n", prog, optarg, strerror(errno));
+        fprintf(stderr, "%s: %s: reopen: %s\n", prog, optarg,
+                mdbx_strerror(errno));
         exit(EXIT_FAILURE);
       }
       break;
@@ -292,7 +293,7 @@ int main(int argc, char *argv[]) {
       if (memchr(key.iov_base, '\0', key.iov_len))
         continue;
       count++;
-      str = malloc(key.iov_len + 1);
+      str = mdbx_malloc(key.iov_len + 1);
       memcpy(str, key.iov_base, key.iov_len);
       str[key.iov_len] = '\0';
       rc = mdbx_dbi_open(txn, str, 0, &db2);
@@ -307,7 +308,7 @@ int main(int argc, char *argv[]) {
         }
         mdbx_dbi_close(env, db2);
       }
-      free(str);
+      mdbx_free(str);
       if (rc)
         continue;
     }
diff --git a/libs/libmdbx/src/src/tools/mdbx_dump.vcxproj b/libs/libmdbx/src/src/tools/mdbx_dump.vcxproj
index b44eb19328..6978a2c22d 100644
--- a/libs/libmdbx/src/src/tools/mdbx_dump.vcxproj
+++ b/libs/libmdbx/src/src/tools/mdbx_dump.vcxproj
@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <Project DefaultTargets="Build" ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <ItemGroup Label="ProjectConfigurations">
     <ProjectConfiguration Include="Debug|Win32">
diff --git a/libs/libmdbx/src/src/tools/mdbx_load.c b/libs/libmdbx/src/src/tools/mdbx_load.c
index a18b50c491..697e3e166f 100644
--- a/libs/libmdbx/src/src/tools/mdbx_load.c
+++ b/libs/libmdbx/src/src/tools/mdbx_load.c
@@ -110,8 +110,8 @@ static void readhdr(void) {
       if (ptr)
         *ptr = '\0';
       if (subname)
-        free(subname);
-      subname = strdup((char *)dbuf.iov_base + STRLENOF("database="));
+        mdbx_free(subname);
+      subname = mdbx_strdup((char *)dbuf.iov_base + STRLENOF("database="));
     } else if (!strncmp(dbuf.iov_base, "type=", STRLENOF("type="))) {
       if (strncmp((char *)dbuf.iov_base + STRLENOF("type="), "btree",
                   STRLENOF("btree"))) {
@@ -237,7 +237,7 @@ static int readline(MDBX_val *out, MDBX_val *buf) {
 
   /* Is buffer too short? */
   while (c1[len - 1] != '\n') {
-    buf->iov_base = realloc(buf->iov_base, buf->iov_len * 2);
+    buf->iov_base = mdbx_realloc(buf->iov_base, buf->iov_len * 2);
     if (!buf->iov_base) {
       Eof = 1;
       fprintf(stderr, "%s: line %" PRIiSIZE ": out of memory, line too long\n",
@@ -340,7 +340,8 @@ int main(int argc, char *argv[]) {
       break;
     case 'f':
       if (freopen(optarg, "r", stdin) == NULL) {
-        fprintf(stderr, "%s: %s: reopen: %s\n", prog, optarg, strerror(errno));
+        fprintf(stderr, "%s: %s: reopen: %s\n", prog, optarg,
+                mdbx_strerror(errno));
         exit(EXIT_FAILURE);
       }
       break;
@@ -348,7 +349,7 @@ int main(int argc, char *argv[]) {
       envflags |= MDBX_NOSUBDIR;
       break;
     case 's':
-      subname = strdup(optarg);
+      subname = mdbx_strdup(optarg);
       break;
     case 'N':
       putflags = MDBX_NOOVERWRITE | MDBX_NODUPDATA;
@@ -378,7 +379,7 @@ int main(int argc, char *argv[]) {
 #endif /* !WINDOWS */
 
   dbuf.iov_len = 4096;
-  dbuf.iov_base = malloc(dbuf.iov_len);
+  dbuf.iov_base = mdbx_malloc(dbuf.iov_len);
 
   if (!(mode & NOHDR))
     readhdr();
@@ -418,7 +419,7 @@ int main(int argc, char *argv[]) {
   }
 
   kbuf.iov_len = mdbx_env_get_maxkeysize(env) * 2 + 2;
-  kbuf.iov_base = malloc(kbuf.iov_len);
+  kbuf.iov_base = mdbx_malloc(kbuf.iov_len);
 
   while (!Eof) {
     if (user_break) {
diff --git a/libs/libmdbx/src/src/tools/mdbx_load.vcxproj b/libs/libmdbx/src/src/tools/mdbx_load.vcxproj
index 6af6cc457c..05a100fc64 100644
--- a/libs/libmdbx/src/src/tools/mdbx_load.vcxproj
+++ b/libs/libmdbx/src/src/tools/mdbx_load.vcxproj
@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <Project DefaultTargets="Build" ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <ItemGroup Label="ProjectConfigurations">
     <ProjectConfiguration Include="Debug|Win32">
diff --git a/libs/libmdbx/src/src/tools/mdbx_stat.c b/libs/libmdbx/src/src/tools/mdbx_stat.c
index a219b9ec0e..95a6cdd23c 100644
--- a/libs/libmdbx/src/src/tools/mdbx_stat.c
+++ b/libs/libmdbx/src/src/tools/mdbx_stat.c
@@ -356,13 +356,13 @@ int main(int argc, char *argv[]) {
       MDBX_dbi db2;
       if (memchr(key.iov_base, '\0', key.iov_len))
         continue;
-      str = malloc(key.iov_len + 1);
+      str = mdbx_malloc(key.iov_len + 1);
       memcpy(str, key.iov_base, key.iov_len);
       str[key.iov_len] = '\0';
       rc = mdbx_dbi_open(txn, str, 0, &db2);
       if (rc == MDBX_SUCCESS)
         printf("Status of %s\n", str);
-      free(str);
+      mdbx_free(str);
       if (rc)
         continue;
       rc = mdbx_dbi_stat(txn, db2, &mst, sizeof(mst));
diff --git a/libs/libmdbx/src/src/tools/mdbx_stat.vcxproj b/libs/libmdbx/src/src/tools/mdbx_stat.vcxproj
index 1adcefde89..4027491d39 100644
--- a/libs/libmdbx/src/src/tools/mdbx_stat.vcxproj
+++ b/libs/libmdbx/src/src/tools/mdbx_stat.vcxproj
@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <Project DefaultTargets="Build" ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <ItemGroup Label="ProjectConfigurations">
     <ProjectConfiguration Include="Debug|Win32">
diff --git a/libs/libmdbx/src/src/tools/wingetopt.c b/libs/libmdbx/src/src/tools/wingetopt.c
index 6ed6dc3cc8..7feb223fc1 100644
--- a/libs/libmdbx/src/src/tools/wingetopt.c
+++ b/libs/libmdbx/src/src/tools/wingetopt.c
@@ -55,7 +55,7 @@ char *optarg;
 int getopt(int argc, char *const argv[], const char *opts) {
   static int sp = 1;
   int c;
-  char *cp;
+  const char *cp;
 
   if (sp == 1) {
     if (optind >= argc || argv[optind][0] != '-' || argv[optind][1] == '\0')
@@ -66,7 +66,7 @@ int getopt(int argc, char *const argv[], const char *opts) {
     }
   }
   optopt = c = argv[optind][sp];
-  if (c == ':' || (cp = (char *)strchr(opts, c)) == NULL) {
+  if (c == ':' || (cp = strchr(opts, c)) == NULL) {
     ERR(": illegal option -- ", c);
     if (argv[optind][++sp] == '\0') {
       optind++;